MESO: Mesoscale Discussion 0145

ACUS11 KWNS 260420
SWOMCD
SPC MCD 260420
MNZ000-SDZ000-NDZ000-MTZ000-WYZ000-261015-

MESOSCALE DISCUSSION 0145
NWS STORM PREDICTION CENTER NORMAN OK
1020 PM CST WED FEB 25 2009

AREAS AFFECTED...SRN ND/NRN AND CENTRAL SD

CONCERNING...HEAVY SNOW

VALID 260420Z - 261015Z

SNOW WILL CONTINUE TO INCREASE/SPREAD ENEWD ACROSS THE DISCUSSION
AREA OVER THE NEXT SEVERAL HOURS...WITH RATES EXPECTED TO REACH
2"/HR. LOCALLY.

LATEST WV IMAGERY SHOWS A STRENGTHENING CIRCULATION CENTER ALOFT NOW
SHIFTING ENEWD ACROSS NERN WY...WITH RAPIDLY INCREASING ASCENT
IMPLIED INTO WRN SD AND VICINITY AS CLOUD TOPS COOL IN CONJUNCTION
WITH THIS FEATURE.

AT THE SURFACE...COLD AIR CONTINUES TO SLOWLY SPREAD SWD EVIDENT BY
SURFACE HIGH PRESSURE RIDGE OVER RED RIVER VALLEY...WHILE ABOVE THE
COLD LAYER A LOW-LEVEL JET CONTINUES TO INCREASE -- WITH GLD VWP NOW
SHOWING 55-60 KT SLY FLOW AT H85. AS ISENTROPIC LIFT/QG ASCENT
STRENGTHEN OVER THE NEXT FEW HOURS...AIDED BY COUPLED JET STRUCTURE
AT UPPER LEVELS WHICH WILL TRAVERSE THIS REGION EARLY THIS
AM...EXPECT SNOWFALL COVERAGE TO EXPAND AND SNOW RATES TO INCREASE.
RATES EXCEEDING 1" PER HOUR ARE ANTICIPATED ACROSS THE DISCUSSION
AREA AND WILL LIKELY REACH 2"/HR. LOCALLY IN A ZONE LIKELY CENTERED
ALONG THE ND/SD BORDER. THE HEAVIEST SNOW MAY AT TIMES BE
CONVECTIVELY ENHANCED -- MAINLY OVER SRN PORTIONS OF THE AREA NEAR
THE NOSE OF THE LLJ. THE HEAVIEST PRECIPITATION WILL SHIFT EWD WITH
TIME...ENDING FROM W-E ACROSS NWRN SD AND SHIFTING INTO NERN SD/SERN
ND THROUGH SUNRISE...IN CONJUNCTION WITH THE PROGRESSIVE UPPER
FEATURE.

..GOSS/SMITH.. 02/26/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.

ATTN...WFO...MPX...FGF...FSD...ABR...BIS...UNR...BYZ...

LAT...LON 43950268 44100335 44460400 45200430 45620390 46760199
47149941 47049691 46839613 46249554 45639558 44959603
44299720 43949904 43900125 43950268

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.