[MCD] SWOMCD

Thu Dec 7 00:39:27 UTC 2006

ACUS11 KWNS 070040
SWOMCD
SPC MCD 070040 
MIZ000-070615-

MESOSCALE DISCUSSION 2272
NWS STORM PREDICTION CENTER NORMAN OK
0640 PM CST WED DEC 06 2006

AREAS AFFECTED...UPPER PENINSULA OF MICHIGAN

CONCERNING...HEAVY SNOW 

VALID 070040Z - 070615Z

BANDS OF LAKE EFFECT SNOW ARE LIKELY TO INCREASE ACROSS PORTIONS OF
THE U.P. OF MICHIGAN BY LATE TONIGHT. LOCALIZED SNOW RATES OF 2
IN/HR OR GREATER WILL BE POSSIBLE ACROSS ALGER/WESTERN
SCHOOLCRAFT/FAR EASTERN MARQUETTE/DELTA COUNTIES...ESPECIALLY
TOWARD/AFTER 06Z.

IN THE WAKE OF THE SURFACE COLD FRONT/PASSING MID LEVEL
TROUGH...INCREASING CYCLONIC FLOW AND OFF-LAKE SUPERIOR TRAJECTORIES
COUPLED WITH UPSLOPE/FRICTIONAL CONVERGENCE WILL FAVOR INCREASINGLY
ORGANIZED LAKE EFFECT SNOW THROUGH THE NIGHT ACROSS THE EAST CENTRAL
U.P. OF MICHIGAN. RECENT TAMDAR SOUNDINGS FROM NEAR MARQUETTE DEPICT
AN INVERSION HEIGHT AROUND 2.5 KM/750 MB EARLY THIS EVENING...WITH
850 MB TEMPS AROUND -19 C. INCREASINGLY COLD AIR ALOFT WILL FAVOR
STRONG LAKE-DRIVEN INSTABILITY OFF OF LAKE SUPERIOR...WITH 850 MB
DELTA-T VALUES AROUND 25 C. ONLY MODEST DIRECTIONAL SHEAR IN THE
BOUNDARY LAYER PER TAMDAR DATA/MARQUETTE WSR-88D VWP DATA WILL
SUPPORT THE GRADUAL EVOLUTION/INTENSIFICATION OF SEVERAL LAKE EFFECT
BANDS...WITH SOME POTENTIAL FOR CONSOLIDATION OVERNIGHT. LATEST
RUC/4KM WRF-NMM GUIDANCE SUGGESTS INTENSIFICATION OF SNOW RATES
TOWARD/AFTER 06Z...ESPECIALLY ACROSS ALGER AND SCHOOLCRAFT COUNTIES
INCLUDING HIGHWAYS 28/94. HIGH SNOW-TO-LIQUID WATER EQUIVALENTS WILL
FURTHER PROMOTE POTENTIAL FOR 2 IN/HR OR GREATER SNOW RATES.

..GUYER.. 12/07/2006

...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...MQT...

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