000
FXUS63 KGRB 272105
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
305 PM CST MON DEC 27 2010
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE IMAGERY SHOW SURFACE HIGH PRESSURE
SLIDING SOUTH OVER THE SOUTHERN MISSISSIPPI VALLEY THIS AFTERNOON.
LOW STRATUS HAS COMPLETELY DISSIPATED OVER N-C WISCONSIN AND THE
LAST GASPS ARE HANGING ON OVER E-C WISCONSIN. THIS STRATUS WILL
DISSIPATE IN ANOTHER HOUR OR TWO. LOOKING UPSTREAM...SEE LOW
PRESSURE MOVING OVER NORTHERN LAKE WINNIPEG WITH A WARM FRONT
EXTENDING SOUTHWARD OVER THE RED RIVER VALLEY. ONLY POCKETS OF LOW
STRATUS MOVING OVER NORTHERN MINNESOTA AHEAD OF THE WARM FRONT.
FARTHER WEST...SEE A COMPACT SHORTWAVE SPINNING INTO NW NORTH DAKOTA
AND ANOTHER WEAKER WAVE OVER NEBRASKA/KANSAS. CLOUD TRENDS AND
TEMPS WILL BE THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS.
TONIGHT...THE STRONG SHORTWAVE OVER NE MONTANA WILL RIDE ALONG THE
US-CANADIAN BORDER TO THE BOUNDARY WATERS OF MINNESOTA. ALONG WITH
A SHORTWAVE MOVING OVER THE SOUTHERN MISSOURI VALLEY...THIS WILL
FORCE SURFACE HIGH PRESSURE TO SLIDE INTO THE SE CONUS. AHEAD OF
THE SHORTWAVE TO OUR NW...WILL SEE A WEAKISH 850MB WARM FRONT/TROUGH
FEATURE CROSS THE REGION LATE IN THE EVENING INTO THE OVERNIGHT.
THIS TROUGH WILL ADVECT MOISTURE IN THE 925-850MB LAYER WHILE THE
BL COOLS TONIGHT...WHICH SUGGESTS THAT LOW STRATUS HAS POTENTIAL TO
RE-DEVELOP. JUST POCKETS OF LOW STRATUS UPSTREAM OVER NORTHERN
MINNESOTA SO CONFIDENCE ISNT HIGH THAT STRATUS WILL REDEVELOP ACROSS
THE AREA. BETTER CHANCES WILL RESIDE ACROSS THE NORTH OVER THE
HIGHER TERRAIN. WILL THROW SCT COVERAGE INTO THE FORECAST ALTHOUGH
SKIES WILL START OUT CLEAR/MOSTLY CLEAR THIS EVENING. A TIGHTENING
PRESSURE GRADIENT WILL KEEP TEMPS UP REGARDLESS IF CLOUDS REFORM AND
INHERITED LOWS IN THE TEENS APPEAR GOOD.
TUESDAY...MAIN ENERGY FROM THE NORTHERN STREAM SHORTWAVE WILL LIFT
NE INTO ONTARIO WHILE THE TAIL END OF THE SHORTWAVE MOVES INTO NORTHERN
WISCONSIN. WILL NOT SEE ANY MOISTURE IN THE MID TO UPPER LEVELS
WITH THIS WAVE...SO DO NOT SEE ANY REAL THREAT OF PRECIP. LOW LEVEL
TROUGH WILL HAVE RAPIDLY PUSHED EAST OF THE AREA BY THE START OF THE
MORNING AND THERE MAY BE SOME RESIDUAL LOW STRATUS HANGING AROUND.
IF THERE IS...SEE THESE CLOUDS RAPIDLY DISSIPATING SIMILAR TO
TODAY. SO THINK WILL SEE MOSTLY SUNNY TO PARTLY CLOUDY SKIES FOR
THE AFTERNOON. SHALLOW ARCTIC AIRMASS WILL KEEP TEMPS IN THE 20S
HOWEVER.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT SUNDAY.
RAPID TRANSITION FROM BENIGN ZONAL FLOW MID-WEEK TO HIGHLY
AMPLIFIED PATTERN BY THE END OF THE WORK WEEK...WITH STORM SYSTEM
FORECAST TO IMPACT THE WESTERN GREAT LAKES REGION NEW YEARS EVE
INTO NEWS YEARS DAY.
LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO SETTLE OVER THE SOUTHEAST
U.S. TUESDAY NIGHT INTO WEDNESDAY. RATHER TRANQUIL CONDITIONS
THROUGH WEDNESDAY AS SOUTHWESTERLY FLOW GRADUALLY INCREASES ACROSS
THE PLAINS AND THE WESTERN GREAT LAKES. TEMPERATURES SHOULD BEGIN
TO REBOUND CLOSER TO THE FREEZING MARK ON WEDNESDAY UNDER PARTLY
CLOUDY SKIES.
THEN MAIN STORM SYSTEM GETS ORGANIZED OVER THE PLAINS DURING THE
DAY ON THURSDAY IN RESPONSE SHORTWAVE ENERGY DIGGING SOUTHEAST
ACROSS THE SOUTHWEST U.S. MODELS SEEM TO BE A TAD SLOWER ON
INITIAL SURGE OF MOISTURE INTO THE STATE WEDNESDAY NIGHT. BACKED
OFF SLIGHTLY ON ONSET OF LIGHT PRECIPTATION TO PRIMARILY AFTER
MIDNIGHT. STILL APPEARS BOUNDARY LAYER WILL BE COLD ENOUGH FOR
INITIAL PRECIPITATION TO BE IN THE FORM OF LIGHT FREEZING DRIZZLE
OR PERHAPS SOME LIGHT FREEZING RAIN. FORCING STILL RATHER WEAK
THUS EMPHASIS ON LIGHT QPF AMOUNTS INITIALLY. AS PREVIOUSLY ADVERTIZED
INCREASING SOUTHERLY FLOW DURING THE DAY ON THURSDAY SHOULD ALLOW
LIGHT FREEZING PRECIP TO QUICKLY TRANSITION TO MAINLY LIGHT RAIN
BY MIDDAY THURSDAY. STILL APPEARS THAT BEST FORCING AND HEAVIEST
PRECIPITATION WILL OCCUR FRIDAY NIGHT AS SURFACE LOW TRACKS NNE
ACROSS WESTERN WISCONSIN AND ASSOCIATED FROPA SWEEPS ACROSS THE
FORECAST AREA. STRONG CAA BEHIND THE FROPA WILL LEAD TO RAPIDLY
FALLING TEMPERATURES AFTER MIDNIGHT FRIDAY INTO EARLY SATURDAY
MORNING. POTENTIAL EXISTS FOR RAPID FREEZING OF RESIDUAL MOISTURE
FROM PREVIOUS RAINFALL AND MELTING SNOW ON AREA ROADS LATE NEW
YEARS EVE INTO NEW YEARS DAY. LATER SHIFTS SHOULD BE ABLE TO
GET A BETTER HANDLE ON TIMING OF FROPA AND ASSOCIATED CAA. LOOKS
LIKE A BLUSTERY AND COLD DAY NEW YEARS DAY WITH GUSTY WESTERLY
WINDS AND STEADY OR SLOWLY FALLING TEMPERATURES THROUGHOUT THE
DAY.
&&
.AVIATION...ANOTHER CHALLENGING CLOUD FORECAST OVER THE NEXT 24
HOURS AS SHALLOW ARCTIC AIRMASS NEVER REALLY LEAVES THE REGION.
CLEARING SKIES THIS AFTERNOON WILL LEAVE VFR CONDITIONS IN PLACE
THROUGH MUCH OF THE EVENING. HOWEVER...WILL SEE A WEAK WARM FRONT
ALOFT CROSS THE AREA TONIGHT WHILE THE SHALLOW BL COOLS. AS THIS
OCCURS...MOISTURE ADVECTION JUST ABOVE THE INVERSION MAY LEAD TO
RE-DEVELOPMENT OF LOW STRATUS. TRIED TO INDICATE THIS POSSIBILITY
IN THE TAFS BY PORTRAYING SCT LOW CLOUDS...BUT NOT CONFIDENT ENOUGH
TO ADD BKN IFR/MVFR CONDITIONS TO THE TAFS AT THIS TIME. WARMER LOW
LEVEL AIR ARRIVES TOMORROW MORNING AND BELIEVE AND LOW CLOUDS WILL
QUICKLY DISSIPATE BY THE END OF THE TAF PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/ESB
