Sunday, March 24, 2013

Powerful Winter Storm moving through Ohio Valley

Saturday, March 9, 2013

Spring Ahead: SET YOUR CLOCKS

Spring ahead!


http://www.marketwatch.com/story/daylight-saving-time-starts-sunday-in-us-2013-03-09?link=MW_home_latest_news

Upper Mississippi Valley Region Flooding Potential

WX UNIT DISCUSSION 03/09/2013 1900Z

FOR OFFICIAL INFORMATION SEE WWW.WEATHER.GOV 

FOR SEVERE THUNDERSTORM AND TORNADO THREATS SEE WWW.SPC.NOAA.GOV FOR AREAS ACROSS THE CENTRAL PLAINS SOUTHWARD INTO EASTERN TEXAS MOVING EASTWARD TONIGHT

DISCUSSION FOR WI AND ADJOINING STATES

HEAVY RAIN AND FLOODING POTENTIAL MOVING IN TONIGHT AND SUNDAY

UPPER FLOW DEFINED BY LARGE TROUGH REGIME MOVING W TO E ACROSS NOAM.  ONE SHORTWAVE ACROSS SCNTRAL CANADA INTO THE NERN HIGH PLAINS OF MONTANA SPLIT FROM A VERY LARGE TROUGH ALONG THE SWRN CONUS AND SOUTHERN PLAINS STATES.  THE VERY LARGE TROUGH HAS A STRONG SPEED MAX THAT DRAPES AROUND IT FROM SRN CAL INTO NRM MEXICO THAT TURNS NEWD ACROSS TX INTO CENTRAL PLAIN/MID MISS VALLEY REGION AND NOW ENTERING THE UPPER MISS VALLEY.   RIDGING NOTED MAINLY EAST OF MISS RIVER VALLEY.

STRG SFC LOW AT 998 MB DVLPNG OVER SWRN KS NEAR DDC WITH INVERTED TROUGH EXTNDG NE INTO MN TO NEAR INL.  

STRG SRLY LOW/MID LEVEL FLOW WITH GOOD GULF MOISTURE TRANSPORT SPREADING NWWD.  FORCING AND LAPSE RATES ALL LOOK GOOD FOR SVR WX SEE WWW.SPC.NOAA.GOV FOR DETAILS.

WI AND SURROUNDING AREAS:

RAIN NOW SPREADING NEWRD INCLDING SOME EMBEDDED TSTMS ACROSS MISSOURI VALLEY WITH STG WAA REGIME WILL BRING IN AREA OF STEADY RAIN SOMETIMES MODERATE AND OCCASIONALLY HEAVY TONIGHT ACROSS ENTIRE REGION.  WITH CURRENT SNOW PACK THE LAST TWO DAYS HAVE BEEN SLIGHTLY MILD DURING DIURNAL HEATING THERE IS A POTENTIAL FOR SIGNIFICANT FLOODING.

SURPRISED THERE ARE NO FLOOD WATCHES OUT FOR WISCONSIN IOWA, PTNS OF SERN MN, AND NRN IL WHERE THERE IS AMPLE SNOW COVER ESPECIALLY IN THE RIVER FLOOD PRONE REGIONS.  AT LEAST RIVER FLOOD ADVISORIES SHOULD BE POSTED ON THIS.  

I MAY OR MAY NOT COVER THIS ANYMORE SO REVERT TO WWW.WEATHER.GOV FOR MORE INFO AND BE ALERT FOR FLASH FLOODING IN HEAVY RAIN TONIGHT AND SUNDAY IF YOU ARE IN A LOW LYING OR FLOOD PRONE AREA.  

WX UNIT


Friday, March 8, 2013

Thursday, March 7, 2013

WX UNIT DISCUSSION 03/07/2013 2200Z

FOR OFFICIAL NWS WX DATA SEE WWW.WEATHER.GOV

BRIEF DISCUSSION FOR WI AND SURROUNDING REGION:

SPRING AND WINTER BOTH IN THE AIR

UPSTREAM UPPER AIR ANALYSIS AND MODEL CONSENSUS PUTS WISCONSIN ON THE BORDER OF RAIN AND SNOW FOR THE NEXT COUPLE OF WEEKS.  COLD AIR IS TRYING TO STAY AROUND AND THE SUBSTANTIAL SNOW COVER CAN AID THIS IF STRONG WAA HOLDS BACK.  

A LARGE POLAR VORTEX/GYRE IS LOCKED IN NORTH OF HUDSON BAY THAT COVERS MUCH OF CANADA.  A VERY COLD CORE REMAINS WITH THIS BUT IT DOES RETROGRADE WEST IN ABOUT A WEEK FROM NOW PERHAPS ALLOWING FOR MORE SOUTHERLY VECTORS TO TAKE OVER.  

A LARGE RIDGE ACROSS THE CONUS RIGHT NOW WILL GIVE WAY TO A LARGE AMPLIFIED TROUGH MOVING INTO THE GREAT PLAINS FOR SUNDAY AND EWWD ON MONDAY.  LOOKS LIKE THE RAIN/SNOW LINE IS RIGHT ON TOP OF WI FOR THIS.  

PRECIP WILL START ALREADY ON FRI WITH WAA AHEAD OF IT WITH A BAROCLINC ZONE AND OVERRUNNING PCPN PROBABLY FREEZING RAIN OR A LIGHT MIX.  

HAVE TO WATCH THE WARM AIR CLOSE WHICH COULD CAUSE RAPID SNOW MELT AND AREA LAKES ARE ALREADY EXPERIENCING THIS TODAY SOON TO BECOME UNSAFE FOR RECREATIONAL ACTIVITY.  

IT'S GOING TO BE ANOTHER WEEK OR TWO WHERE WINTER DOES TRY TO STICK AROUND AND EVEN THE NCEP MODELS PREDICTING BELOW NORM TEMPS BUT THE WARM AIR TO THE WEST AND SOUTHWEST NEEDS TO BE MONITORED CLOSELY SHOULD IT NUDGE INTO HERE WITH CLEAR SKIES.

WE COULD EASILY SEE A SITUATION WHERE IL IS IN THE 60'S AND WITH LACK OF CLOUD COVER A RAPID SNOW MELT PICKS UP.  WATCHING A POSSIBLE RAIN EVENT FOR SUNDAY WHICH COULD CAUSE PROBLEMS WITH THAT. 

KEEP UP WITH THE FORECAST.

WX UNIT

Tuesday, March 5, 2013

WX UNIT DISCUSSION 03/05/2013 2310Z

FOR OFFICIAL INFO SEE WWW.WEATHER.GOV

SPECIAL DISCUSSION....SERN AND ECNTRL WI....

NOTABLE QG FORCING WITH PERSISTENT WARM MOIST SERLY 800 TO 650MB FLOW DRIVING NWWD ACROSS SRN LK MICH CONTINUING TO ENHANCE SOME LOCALIZED HEAVIER SNOW BANDS EMBEDDED IN THE ONGOING AREA OF LIGHT SNOW.  

ONE PARTICULAR HEAVIER BAND OF SNOW HAS DEVELOPED ACROSS PTNS OF MILWAUKEE, OZAUKEE, WAUKESHA, WASHINGTON, DODGE COUNTY, FOND DU LAC, CALUMET AND WINNEBAGO COUNTIES.  A STRONG RADAR RETURN AT 2350Z IS NOTED NOW OVER MUCH OF WASHINGTON COUNTY MOVING WWD.

SOME OF THESE HEAVIER SNOW SQUALLS THAT HAVE RECENTLY DEVELOPED COULD ADD AN ADDTL 2 TO 4 INCHES IN SOME LOCATIONS BUT IN GENERAL ONLY AN INCH OR LESS IS EXPECTED ELSEWHERE.  

WILL WATCH THE MOVEMENT OF THESE SQUALLS AS THEY COULD EXPAND WWD INTO GREEN LAKE AND COLUMBIA COUNTIES WITH THE THREAT OF ADDTL ACCUMULATION THERE ALSO. 

SOME AREAS OF BLOWING AND DRIFTING ALSO LIKELY TONIGHT. 

SEE MXK WARNINGS AND ADVISORIES AT WWW.CRH.NOAA.GOV/MKX

WX UNIT

 


WX UNIT DISCUSSION 03/05/2013 2000Z

SRN WI AND NRN IL AND SURROUNDING AREAS:

FOR NWS OFFICIAL INFORMATION SEE WWW.WEATHER.GOV

...UPDATE FOR WEAKENING TRENDS...

WEAKENING TRENDS OBSERVED NOW ON THE SNOW ACRS SRN WI AND NRN IL EXCEPT FOR THE IMMIDIATE CHICAGO METRO AREA AND UP TOWARD MILWAUKEE.  RADAR RETURNS SEEM MORE ROBUST THAN ACTUAL INTENSITY OF SNOW AS LOW LVL WRM AIR ADVECTION WRAPPED IN AND CAUSED SOME LOW LEVEL FOG MIXED IN WITH SNOW REDUCING SFC VIS.   1/4 TO 3/4 MILS VSBLTY REPORTS MADE IT SEEM AS IF SNOW WAS HEAVIER BUT ACCUMS OVER 4 AND 5 INCHES ARE HARD TO FIND.  SHOULD SEE NWS REDUCE WARNINGS TO ADVISORY CRITERA OR EVEN CANCELLED ALTOGETHER AS ONLY AN INCH OR LESS CAN BE EXPECTED JUST ABOUT EVERYWHERE.  THERE MAY BE SOME ISOLATED BANDS THAT PRODUCED SOME ADDTL ACCUM BUT IT IS RAPIDLY WASHING OUT NOW.

UPSTREAM HIGH PRESSURE MOVES IN AND IT COULD GET COLD AROUND HERE THE NEXT COUPLE OF NIGHTS IF WE CAN CLEAR OUT THE OVERCAST.  NEXT SYSTEM SWINGS UP THROUGH THE CENTRAL PLAINS FOR FRIDAY AND SATURDAY AND IT LOOKS LIKE A PANHANDLE HOOK.  COULD BE A WARM RAINY SYSTEM WITH AMPLE MOISTURE AND CAUSE SOME FLOODING CONCERNS COUPLED WITH MELTING SNOW. 

SPRING IS ALMOST IN THE AIR NOW.

STORM CHASER DAVID CASPER, WX UNIT   Current Regional Radar (REFRESH FOR UPDATE)...

Woman Rides Out EF4 Tornado

Winter Storm Saturn In Progress

Are we naming WINTER STORMS now?
Is the next one upstream Jupiter?


Perhaps we will name SUPERCELLS and TORNADOES next?

...developing...

WX UNIT UPDATE 03/05/2013 1200Z

DISCUSSION FOR SRN WI NRN IL AND VCNTY:

FOR OFFICIAL INFORMATION SEE WWW.WEATHER.GOV

UPDATE/REVISIONS:

HAVE ADJUSTED MY SNOW ACCUMS DUE TO A BACKDOOR PUSH OF DRY COLD AIR ACRS NERN WI UNDERCUTTING THE PCPN AS IT DRIFTS NORTH.  DEW POINTS IN THE TEENS NOTED FROM MANY REPORTING STATIONS ACRS NE HALF OF WI AND CIGS AT MSN AT OVC055 AND MKE OVC038 RIGHT NOW NOT DROPPING MUCH.  THINKING HVST SNOW ACCUMS WILL CERTAINL REMAIN S AND W OF EAU TO DLL TO UNU TO MKE LN WITH A GENERAL 4 TO 8 INCHES OF ACCUM LIKELY.  LESS AMTS TO THE N AND E OF THIS LINE BUT WILL WATCH DODGE, WASHINGTON, OZAUKEE, FOND DU LAC, AND SHEBOYGAN COUNTIES, PERHAPS A PORTION OF GREEN LAKE FOR THE USUAL PERSISTENT DEFORMATION ZONE WHICH COULD BE ENHANCED BY LAKE EFFECT FOR A BRIEF TIME LTR THIS AFTN.

ARX CWA MAY END UP WITH A BIT HIGHER AMTS RIGHT ALG THE MISS RVR BECAUSE OF THE PREVIOUS PERSISTENT SNOW BAND IN THAT REGION. 

SNOW SHOULD BE GONE BY EVE TODAY AND A PEEK AT THE AFTN SUN PRIOR TO SUNSET IS ENTIRELY POSSIBLE LATER ON IN SOME AREAS.

COLUMBIA, SAUK, ADAMS, GREEN LAKE AND MARQUETTE COUNTIES WILL PROBABLY GET AROUND 3 TO 5 INCH TOTALS. 

MORE UNCERTAINTY:  
HAVE CONSIDERED BROAD BRUSHING THIS EVENT WITH SNOW S OF LINE FROM EAU TO STE TO OSH TO SBM WITH A GENERAL 4 TO 8 INCH POSSIBLE SNOWFALL WITH HIGHER AMOUNTS ALNG AND S OF A LN FROM EAU TO BCK TO DLL TO UNU TO MKE POSSIBLE.  IT'S HARD TO SAY.  BUT I'M NOT THE ONE WHO HAS TO MAKE THE FINAL CUT FORECASTS SO I'M GOING TO DO WHAT I DO BEST---MONITORING. ;-) 

THIS REALLY LOOKS LIKE IT'S GOING TO POUND RFD OVER TO ORD MDW AND THE ENTIRE CHICAGO METRO AREA EASTWARD TOWARD SBN AND TOL.

WATCH THE RADAR FOR YOUR BEST GUESS SCENARIO:
Current Regional Radar (REFRESH FOR UPDATE)...




STORM CHASER CASPER WX UNIT

WX UNIT DISCUSSION 03/05/2013 1030Z

UNUSUALLY DISORGANIZED WEATHER AND DIFFICULT FORECAST NOW BECOMING BETTER REALIZED:

THE COMPUTER MODELS ARE NOT AIDING FORECASTERS

WX UNIT DISCUSSION FOR WI AND ADJOINING STATES:

This is one of those times you have to chuck the models no matter how wonderful you may think they are and quite honestly I'm not going to even peek at one.  In fact when I look at data I look at the basics:
  • WINDS ALOFT
  • SURFACE DATA
  • RADAR
  • TRENDS
  • SATELLITE TRENDS
  • NATIONAL COMPOSITE TRENDS
  • RUC ANALYSIS (WELL I'M FORCED TO DO THIS ONE)
Actually I'm kind of a dinosaur when it comes to this stuff because I think the name RUC was changed to RAP but that doesn't matter right now and I still believe rain showers and snow showers should be written as RW and SW instead of the NEW WORLD ORDER METAR FORMATS WHICH I CANNOT STAND.  Thank you very much.

This complicated weather system that has been changing it's shape over the last 24 hours is making a slower progression eastward and has proven to be a forecast pest so far and also proves the importance of really knowing your weather. As the saying goes, "Weathermen are the only ones that can be wrong and still keep their job."  Well I wasn't even wrong and wasn't able to keep mine---but that's another story.

This shortwave has very impressively amplified now across the nation's mid section and is funneling in a very notable cold air mass behind it with gusty winds driving south across the Great Plains deep into Texas.   A strong surface cold front runs from eastern Texas through the ARKLATEX region northeastward into a strengthening area low pressure area now taking shape just west of Memphis.  From this low a well defined inverted trough has formed north westward into eastern Iowa and then further northwestward into the eastern Dakotas where another are of low pressure is now morphing into that inverted trough.  

This system is tapping the Gulf moisture flow now and it looks like GAME ON for a MAJOR WINTER STORM EVENT that is likely to produce some incredible amounts of snow and SEVERE WINTER CONDITIONS including all modes of severe weather from winter storm and blizzard conditions to freezing rain, sleet, rain, severe thunderstorms and even some possible isolated tornadoes.  This is also creating setup for major flooding given more upstream storms are expected by mid March with a market warming trend and above normal precipitation which could induce major flooding in a week or so.   Any warming trend coupled with large amounts of rain on top of what this storm will lay down for snow accumulation is certain to cause some flooding concerns.  

For now this remains a difficult forecast to pinpoint the exact location of heavy snow and mark the areas where the usual 1-3, 4-6, 6-10, or 8-14 inch snowfalls will occur.  Ongoing area of light snow with some scattered heavier snow bands that has persisted over the last 18 hours in the upper Mississippi valley region and upper Midwest continues to persist in an area of forcing just east of the inverted trough across much of Minnesota, eastern Iowa, northeastern Missouri and western Illinois now moving into extreme western Wisconsin.  This area prompted the onset of Winter Storm Watches and Warnings on Sunday and produced some impressive snow amounts across North Dakota with areas receiving on the order of generally 6 to 15 inches of snow depending on location.  Across Minnesota and Iowa this has been generally a 2 to 6 inch accumulations.  

This storm system concerns me since it has not been as progressive as I initially expected it to be.  For starters it looked like an Alberta Clipper type system would merge into sort of a western type system but downstream and off the east coast an UPPER ATMOSPHERIC BLOCKING PATTERN with a retrograding cyclone of the coast of New Brunswick seems to have been holding the progressive flow back a bit.  The southern stream has become well pronounced now at H500 and above and is rifling a strong jet stream west to east across the south half of the continental United States.   This has cause a real brain teaser of a forecast pest as it had the makings of each of the four main types of winter low pressure systems that would usually affect this region.  They are:

1)  The Alberta Clipper
2)  The western type low
3)  The Panhandle Hook
4)  The Lower Mississippi Type low

This system initially gave a blend of everything but for now we will get on with the discussion and expected track of this storm below:

KEEP IN MIND THERE IS ANOTHER STORM UPSTREAM OFF THE WEST COAST THAT NEEDS WATCHING FOR LATER THIS WEEK AND NEXT.

I'M GOING TO ABBREVIATE THE REST OF THIS TO SAVE TIME:

STRG WELL AMPLIFIED SWAVE NOW IN CENTRAL US AS YESTERDAY'S NRN STREAM NOW MERGED WITH SRN BRANCH UPR FLOW.  SFC LOW J W OF MEM AROUND 1007MB AND WATCHING WITH GREAT INTEREST TO SEE IF THIS WILL FALL BELOW 1000MB DURING NEXT 6 HOURS.  STRGR JET MAXES ARE IN SRN TX AND ALSO THE WRN HIGH PLAINS DIVING S ALG WRN PERIPHRY OF TROUGH.  

LOOKS LIKE A LARGE SCALE SNOWFALL WILL DUMP ALONG AND N OF STORM TRACK AS MEM LOW MOVES SLOLY NEWD INTO OH VLY RGN AND THEN PROBABLY EWWD INTO THE DELMARVA.  HPC TRACK SHOWN BELOW LOOKS ACCURATE ENOUGH GIVEN CURRENT DYNAMICS:
CLICK TO ENLARGE
NEED TO MENTION IMPRESSIVE INVERTED TROUGH AND NOTABLE MOISTURE FETCH WHICH WILL WRAP AROUND THE NRN PERIPHRY OF STRM SYS TO CAUSE ADVISORY CRITERIA SNW ALG AND N OF HVY SNOW DEFORMATION ZONE LIKELY TO CAUSE ADDTL SHORT TERM FCST  ADJUSTMENTS AS THE SYSTM UNFOLDS ACROSS ALL OF WI AND INTO LOWER MICH.

LOOKS LIKE THE STORM SYS IS GOING TO RAKE SRN WI, NRN IL, SRN LK MICH, IN, OH, SRN LWR MICH, EWWRD WITH IMPRESSIVE HVY SNOW ON THE ORDER OF 6-12 INCHES MAKING TRAVEL HAZARDOUS.  IT MAY MOVE SLOW WHICH COULD CAUSE SOME AMTS TO BE AMENDED TO HIGHER ACCUMS AS THIS SYTEM MOVES E ESPECIALLY IN THE HIGHER APPALACH MTN AREAS AND EWWD.  KEEP UP WITH THE FORECAST.

UPSTREAM IS ANOTHER MAJOR CONCERN WITH NEXT SYS MVG ONSHORE ALG U.S. WEST COAST.  WILL DISCUSS THIS FURTHER IN NEXT DISCUSSION.

PRESENT THOUGHT IS HVST SNOW IN WI HERE WILL REMAIN SO OF A LINE FROM MSN TO MKE BUT DOES NOT DIMINISH THE POTENTIAL OF SOME ISOLD HIGHER AMTS N OF THIS LINE.  I'LL CALL 6-10 SO OF A LNR MSN MKE LINE and 4-6 INCHES N OF THIS LINE.   RFD TO ORD AND EVEN ENW AND RAC COULD GET SOME 12+ INCHES.  MIGHT HAVE TO ADJUST THE LINE FROM SAY MSN TO UNU TO SBM IF LOW TRACKS FURTHER N.  
ALL INTERESTS SHOULD KEEP UP WITH THE FORECAST ON THIS ONE AND PLAN TRAVEL SAFETY ACCORDINGLY.  

FOR OFFICIAL INFORMATION SEE WWW.WEATHER.GOV 

STORM CHASER CASPER WX UNIT




Monday, March 4, 2013

Computer Models Do Most Forecasting Today

Today we have a blend of many COMPUTER MODELS that do all the forecasting and forecasters decide which one they like or they average them out to come up with a best guess scenario for storm systems.   They have proven to be quite accurate tools for the trade however when it comes to severe weather such as supercell thunderstorms, tornadoes and flooding that will always need the storm chaser, storm tracker, or weather spotters.  

Although it seems the technology seeks to replace man I prefer real people to spot and report tornadoes and various other severe thunderstorm criteria including flooding, hail, wind damage, etc.  NEXRAD RADAR improvements have come a long way and are very helpful and there is less excuse today for people to not know what is going on weather-wise: 



...developing...

WX UNIT DISCUSSION 03/04/2013 0730Z

Monitoring Winter Weather Development Across Central United States

WX UNIT DISCUSSION and FORECAST TRENDS:  MAINLY WISCONSIN AND ADJOINING STATES

SEE FOR www.weather.gov FOR LATEST WATCHES, WARNINGS, AND ADVISORIES and "OFFICIAL" INFORMATION....

THE FOLLOWING IS "UNOFFICIAL"...

Progressive and broad upper level flow across the continental United States is becoming more zonal with time as the trough in the eastern half from earlier today is progressing eastward and the upper level ridge breaks down in the central United States.   A broad based split flow regime is now across the Rocky Mountain region moving into the Great Plains with a strong broad zonal flow of around 100KT coming in off the Pacific Ocean across southern California and the Great Basin into the southern Plains of Texas and Oklahoma.  The northern stream is wrapping around a vortex positioned along the U.S. and Canada border over norther Montana, southwestern Saskatchewan and southeastern Alberta.  Shortwave flow associated with this vortex noted from the western Dakotas westward into Idaho and then arcing northwestward across Washington State into the offshore region of British Columbia.  The shortwave has not amplified much but gives the appearance of a slight positive tile while the upper ridge from earlier today has flattened a bit at the H500/H300 levels.  

At the surface there is a broad area of cyclogenesis orientated north to south along the eastern high plains now drifting more into the central Plains from the panhandles of Texas and Oklahoma northward across western Nebraska and into the western Dakotas and eastern Montana.  Three primary areas of low pressure with the strongest noted between Enid, Oklahoma and Gage, Oklahoma, another in extreme northwestern Nebraska around Alliance and the third low located in western North Dakota.  

The southern low exhibits a trough extending southward into Mexico while the Nebraska low is exhibiting a trough extending northward through the other lowest pressure plot in western North Dakota with the trough turning northwest from there into northeastern Montana.  The Nebraska low exhibits another trough line from near Alliance (AIA) southwestward into southeastern Wyoming and then westward into the Casper, Wyoming (CPR) area.  Between the Nebraska surface trough and the North Dakota and northeastern Montana troughs there is a pronounced ridge of high pressure from western South Dakota westward along the Wyoming and Montana border which then curves northwestward across the Rocky Mountain range or western Montana northwestward into British Columbia.

Strong isobaric gradient from the surface to mid levels with the shortwave across western Montana where strong winds have been noted across central and western portions of Montana today.  Those strong winds started as a quasi-Chinook wind event earlier today with some compressive warming noted earlier for a time in Montana but have been undercut now by a colder core of air wrapping around the Montana vortex.   Still some fairly strong winds noted at several stations including at Billings (BIL), Livingston (LVM),  Lewistown (LWT),  Great Falls (GTF), Helena (HLN), Butte (BTM), Havre (HVR), Cut Bank (CTB), and Bozeman (BZN) areas with some gusts into the 35 to 40 MPH range.  Strong winds also noted across southeastern Alberta and southern Saskatchewan.   

All these ingredients are making for a very difficult forecast as the system exhibits a winter storm potential but the target snow area will be difficult to determine.  Apart from using any model consensus my earlier discussion is right on target as this system is a blend of not only an Alberta Clipper system but also a Western Type Low and even some shades of a Panhandle Hook.  Let me explain this below:

It should also be noted that this system has a narrow band of H850 to H700 frontogenetic forcing going on along and juxtaposed with the entire Missouri River Valley Region from the STL area northwestward though Iowa, southwestern Minnesota and into the Dakotas.   This boundary is the primary focus for the development of a wintery mix of precipitation that is ongoing at the moment in a narrow band extending across central Iowa, southwestern Minnesota, northeastern South Dakota and into North Dakota and northeastern Montana.  

I want to point out the strongest surface low right now in northwestern Oklahoma because it has some strong surface features for this time of year but is in a very dry air mass lacking anything but a trace of Gulf Moisture transport even at the H925 and H850 levels.   From the surface low that is to the wast of Enid, Oklahoma (END) centered right around Gage, Oklahoma (GAG) is a dryline/dry-wedge to the south-southwest along with some impressive temperature contrasts surrounding this low and very little moisture flux being transported northward.  Strong winds are also noted down in this region as this low center intensifies around 997MB.  I'm going to plot this rather that explain it below.  As you can see this is so far nothing but a dry windy system with some dew point density and temperature boundaries that are wrapping around this system:
CLICK TO ENLARGE

Could it be that this southern branch will actually take over and form an impressive storm for the eastern United States for late Monday and into Tuesday?  It appears worth watching to me to see how this unfolds over the next 12 to 18 hour period. I could continue to go into all manner of details on this but I'm going to hold off an submit to COMPLETELY SHORT TERM MONITORING OF THIS PARTICULAR SYSTEM.  All manner of lengthy discussion is not worth the time as this does not appear to be a dangerous winter storm however it will cause the usual travel difficulty with considerable snow and the blowing and drifting attributes.  

Meanwhile we have this boundary to contend with in the Missouri Valley Region producing an area of light snow and some mixed precipitation right now but it does not appear to be too intense save for a few stronger isolated snow bands.  The heaviest activity is noted right in the Des Moines, Iowa (DSM) vicinity and in east central North Dakota:
From here and based on the trends I don't see a major snow producer given the fact that the dynamics of this system have lost some moisture now until it moves east of the Mississippi River and can tap into some Gulf moisture but with lack of southerly flow at the moment it seems the southern branch of this storm will remain a dry windy event and the northern branch will be an aggressive Clipper like system with about a 4 to 6 inch variety snow event in a narrow configuration with some localized higher amounts possible in a few counties across portions of North Dakota, Minnesota, and Iowa during the next 12 hour period.  The caviat comes late Monday however depending on the speed of this Montana shortwave and how it transitions into the southern stream and also if it can realize some increased moisture transport from the Gulf of Mexico.  More information on this will be forthcoming tomorrow afternoon when a better look at data and trends is realized. 

How this system progresses and redevelops in the mid-Mississippi Valley and Ohio Valley could spell some considerable higher snow amounts for places like Milwaukee (MKE), Chicago (ORD, MDW), Rockford (RFD), South Bend (SBN), Toledo (TOL), Fort Wayne (FWA) and Indianapolis (IND) eastward. 

For now KEEP UP WITH THE FORECAST especially across areas such as NORTHERN ILLINOIS, SOUTHERN WISCONSIN and eastward as this system needs to be monitored for redevelopment across the mid-Mississippi and Ohio Valley areas late Monday and early Tuesday.  

CASPER/MOEN  THE WEATHER UNIT.COM

 

Sunday, March 3, 2013

WX UNIT DISCUSSION Sunday March 3, 2013

REGIONAL 1200Z  MAR 3, 2013 SYNOPSIS for WISCONSIN and ADJOINING STATES:

(Hi guys I know I haven't done this in a while.  I'll do this one in plain language instead of the usual abbreviations.  Some readers that aren't into weather don't understand the other format but I won't do this very often so those who don't like it might have to learn the other and get with the program.  I guess I'm getting the itch for severe weather season so this is my way of warming up the brain cells again so I can get away from The News UNIT a bit.)

A relatively strong winter storm system is expected to develop for the upper Mississippi valley, upper Midwest region, the mid Missouri Valley region and portions of the northern Great Plains Monday through late Tuesday. 

Currently a shortwave is evident via water vapor imagery over southwestern Canada with a surface area of low pressure developing over southern Alberta, Canada.  The latest satellite and upper level synopsis shows a large upper level trough across the eastern Continental United States and pronounced ridging across the western half of the United States.  

A narrow stretch of meridional high pressure is noted from central Ontario, Canada to the Gulf Coast which runs the entire length of the Mississippi River Valley with weak ridging noted from Wisconsin northward where overnight temperatures have dropped below zero Fahrenheit across much of central and northern Wisconsin.

Snowfall across much of the region is rather thick with amounts in many areas which will be difficult to erode as warm air advection approaches from the west over the next 18 to 24 hours and ends up keeping the surface freezing level generally west of the Mississippi River save for a few hours this afternoon under sunny skies and peak insolation.  

The next storm system is peculiar in that my initial thoughts were here comes an Alberta Clipper system however upon further observation there is a copious amount of maritime moisture fetch noted at H700 and a rather robust vorticity max noted moving in on the upper ridge along the northwestern U.S. and southwestern Canadian border region.  Also some strong orographic lift was noted on water vapor imagery along the higher mountain range in western Montana northwestward into southeastern British Columbia.   This lift along with ample moisture flow at mid and upper levels is causing considerable cloudiness to spill over from the northern Rockies into the northern and central Plains states with some spotty precipitation indicated on NEXRAD composites but mainly virga for now as moisture has not saturated the column yet with this next event.
 
I haven't looked at any models but I did glance at a forecast discussion out of the MKX office and saw the Winter Storm Watches and advisories starting to light up from North Dakota southeastward into the Corn Belt region.  I think it's a bit hasty for a Winter Storm Warning across North Dakota and will only mention that with the understanding that forecasters in that region have their own reasons for that as my focus is primarily on Wisconsin and adjoining states.

While this is not the usual WX UNIT discussion I'll consider this a preliminary discussion of observations as I see them happening right now at 1200Z Sunday.  

One more observation I have not mentioned is a rather strong surface trough of low pressure that runs along the lee of the Rockies from eastern New Mexico northward through eastern Colorado and into easten Wyoming.  

Although my initial impressions were perhaps forecasters are expecting a strong clipper system this could reorganize into a potent western type low with a storm track from around KAIA in western Nebraska eastward as it seems there is some initial weak cyclogenesis already in process there.

Further trends will be monitored from here and I will give my detailed forecast later today after reviewing satellite and upper air trends along with the usual peek at the GFS and NAM as I'm a bit old fashioned in forecasting the weather.  Unfortunately things are so model based today we basically forecast from these models and are forced into RUC analysis and all the computer soundings during the height of the storms.  

Either way this system needs to be watched for these primary reasons:
1) The upper level flow is strong 
2) There is a strong vorticity max that is impinging on the western U.S. ridge
3) Unusually strong cyclogenesis already occurring (but will reorganize later on)
4) Copious amount of maritime moisture unlike the usual expectations
5) Large amount of snow cover across Midwest and northern Plains along with deep snow cover from the eastern Dakotas across Minnesota and into much of Wisconsin and inland Lakes well frozen with ice as much as 1 to 2 feet thick in some locations.  

I will also note that there is a chance at a reasonable mild day if the cloudiness can hold off through peak heating and a good day for outdoor activities with no real windy conditions expected across much of the region.

It's still somewhat of a toss up whether this is going to be an Alberta Clipper type system or a Western Type Low.  It may be a blend of both.  

As usual--KEEP UP WITH THE FORECAST

Storm Chaser, David Casper, The WX UNIT

ADDITIONAL COMMENTS:  I see I haven't mentioned snow amounts but I will say I am impressed with the forecasters calling for 4 to 8 and 6 to 10 which immediately got my attention.  I'll be covering this in greater detail later on.  Have a good one!  Don't over cook the books on this too soon. :-) 

Also want to add here that the only reason I looked at the charts today was because I got up here with NO DEGREES on the thermometer and thought "When is it going to warm up?" so I first checked the H500 and then thought O good a ridge.  Then I glanced at the other levels and things immediately looked dicey.  I then spun a 48 hour water vapor of NOAM and I was hooked like fish on this one when I saw that flow to the west.  Yikes!  Winter isn't over yet. 

And one more thing for those of you running the HAARP and NEXRAD transmitters to enhance this storm...yea right?  :-)  Of course I'm kidding.  You don't think I'm a conspiracy nut job do you?

EXTENDED OUTLOOK THOUGHTS:

I just can't quit today:  If that GFS is right this looks like a clipper to be albeit a strong one.  I see NCEP and HPC really have some handsome looking charts now in greater detail than before.  Nice.  Makes the storm look pretty doesn't it?  LSE is going to get pounded and Chicago could get hit quite hard.  Too soon to call but there's a lot of red on the charts:

This is not good folks!  If we get the snowfall like this from this one we have a major warming trend in the middle of the month and what looks like one of the stronger spring cyclones I've seen coming around the 13th.  This could spell some major epic springtime flooding problems that need to be discussed for various rivers and tributaries.  Hopefully this one ends up stacking as a big dry windy cyclone but the H850 PW is rather intense.  Could be some long track supercells to the south.

People need to be aware that we could really have a serious springtime flooding problem on our hands.  Definitely keep up with the forecast if you live in a FLOOD PRONE AREA.

Any questions on your region feel free to ask below in the COMMENT section.  I don't charge for forecasting--yet. :-)
If this is a CLIPPER SYSTEM this is one of the strongest CLIPPER SYSTEMS for snowfall amounts I have ever seen in my life.  My doubt meter just went up a bit.  

...developing...