FXUS63 KMKX 262127
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
327 PM CST THU NOV 26 2009
.SHORT TERM...
TONIGHT...FORECAST CONFIDENCE: HIGH
UPPER LOW AND CORRESPONDING OCCLUDED SFC LOW WILL CONTINUE TO MOVE
OFF TO THE NORTHEAST TONIGHT. CLOUDS WILL BE SLOW TO SCATTER OUT.
GFS AND NAM HANG ON TO 925MB HIGH RH OVER THE SOUTHEAST UNTIL AFTER
09Z. 925MB TEMPS AROUND -4C TONIGHT WITH VERY LITTLE INVERSION
SPELL OUT MIN TEMPS AROUND 25F. CLOUDS SLOWER TO SCATTER OVER THE
EAST SHOULD KEEP TEMPS A LITTLE MORE MODERATE BUT NONETHELESS
RIGHT AROUND FREEZING. IT WILL FEEL COLD TONIGHT SINCE THE TEMPS
HAVE BEEN SO MILD LATELY...BUT THEY ARE ACTUALLY RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR.
FRIDAY...FORECAST CONFIDENCE: HIGH
UPPER LEVEL SHORTWAVE ROUNDING THE TOP OF THE RIDGE OVER MONTANA AND
APPARENT ON WATER VAPOR IMAGERY COULD CAUSE A FEW HIGHER CLOUDS TO
TREK OVER THE REGION ON FRI. WEAK SOUTHERLY WINDS WILL KICK IN AND
925MB TEMPS WILL BE ON THE RISE IN THE AFTERNOON WITH THE RETURN
FLOW AROUND THE SFC HIGH...SO HIGH TEMPS SHOULD BE IN THE LOWER 40S.
AGAIN...RIGHT AROUND CLIMATOLOGICAL AVERAGE.
925MB TEMPS WILL RISE ANOTHER 3 TO 4C OVERNIGHT FRI NIGHT. LOW TEMPS
TRICKY SINCE SKIES WILL BE MOSTLY CLEAR...BUT WARM AIR WILL STILL BE
ADVECTING ALOFT. GOOD INVERSION EXPECTED OVER THE LAND.
SATURDAY...FORECAST CONFIDENCE: HIGH
THIS SHOULD BE A VERY NICE DAY UNDER THE UPPER LEVEL RIDGE AND FAIRLY
ZONAL FLOW AT 500MB. MODEL SNDGS SHOW MIXING UP TO AROUND 925MB WITH
SOME POSSIBLE AFTERNOON WARM AIR ADVECTION CLOUDS AND DRY AIR
ALOFT. WITH 925MB TEMPS AROUND 4C...STRAIGHT MIXING DOWN WOULD
GIVE A HIGH BETWEEN 50 AND 54F. WENT WITH STRAIGHT MODEL
GUIDANCE...WHICH WAS A LITTLE ON THE CONSERVATIVE SIDE...KEEPING
HIGHS IN THE UPPER 40S TO RIGHT AROUND 50.
.LONG TERM...
SATURDAY NIGHT THROUGH SUNDAY NIGHT...FORECAST CONFIDENCE: LOW
UPPER DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF THE JET...AS
WELL AS WEAK SHORTWAVE ENERGY AHEAD OF THE MAIN 500MB SHORTWAVE
SWINGING ACROSS THE NORTHERN BORDER OF THE COUNTRY...MAKES THE FCST
A LITTLE TRICKY FOR THIS TIME PERIOD. THESE FEATURES COULD PRODUCE
ENOUGH INSTABILITY TO WARRANT THE MENTION OF SPRINKLES OR FLURRIES
OVER MUCH OF THE CWA.
THE GFS AND ECMWF BOTH GENERATE A SFC LOW WITH A FRONT STRETCHING
FROM LAKE HURON DOWN THROUGH SOUTHERN IL AND INTO TEXAS ON SUN.
GIVEN THE PLACEMENT OF THE FRONT JUST TO THE SOUTHEAST OF OUR CWA
BORDER AND THE UNCERTAINTY IN THE FCST...WENT WITH SCHC POPS IN THE
FAR SOUTHEAST CWA FOR SUN AND SUN NIGHT. KEPT PRECIP TYPE A RAIN-
SNOW MIX SINCE 925MB TEMPS WILL BE AROUND -2C AND SFC TEMPS FCST
AROUND THE FREEZING MARK IN THE AREA OF PRECIP.
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE: MEDIUM
SFC LOW AND FRONT WILL MOVE OFF TO THE EAST AND HIGH PRESSURE WILL
MOVE INTO THE REGION. HIGH TEMPS WILL BE COOLER IN THE UPPER 30S AND
CLOUDS COULD LINGER OVERHEAD FROM UPPER LEVEL SHORTWAVE ENERGY.
MODELS DIVERGE IN SOLUTIONS IN THE EXTENDED. BOTH SHOW A POTENT
500MB SHORTWAVE TRACKING ACROSS THE US/CANADIAN BORDER WHICH
GENERATE A SFC LOW JUST AHEAD OF IT. THE GFS IS MORE PROGRESSIVE
THAN THE ECMWF. HOWEVER...BOTH SCENARIOS KEEP THE LOW FAR ENOUGH
NORTH SO THAT SOUTHERN WI REMAINS IN THE DRY SECTOR OF THE LOW
PRESSURE SYSTEM THROUGH WED.
THURSDAY...FORECAST CONFIDENCE: LOW
THE 12Z ECMWF MODEL BRINGS A SFC LOW NORTH OUT OF THE GULF AND
MERGES IT WITH A SFC LOW TRACKING ACROSS THE US/CANADIAN BORDER
RIGHT OVER OHIO ON THURSDAY. THIS WOULD PUT SOUTHEAST WI ON THE
OUTER FRINGE FOR PRECIP...SNOW...WITH THE SYSTEM. MEANWHILE...THE
GFS KEEPS THE SYSTEMS SEPARATE AND NOTHING WOULD HAPPEN IN
SOUTHERN WI. WILL HAVE TO WAIT AND SEE WHAT THE NEXT MODEL RUN
DOES...
&&
.AVIATION...NORTHWEST WIND GUSTS TO 25 KNOTS SHOULD GRADUALLY
SUBSIDE BY 02Z FRIDAY...AS LOW LEVEL WINDS WEAKEN. AREA OF MVFR
CEILINGS TO GRADUALLY RISE TO VFR AND BECOME SCATTERED BETWEEN 05Z
TO 07Z FRIDAY ACROSS TAF SITES. HIGH PRESSURE MOVING SOUTH OF
WISCONSIN WILL THEN BRING VFR CONDITIONS THROUGH FRIDAY...WITH SOME
MID TO HIGH CLOUDS.
&&
.MARINE...SMALL CRAFT ADVISORY CONTINUES THROUGH 10Z FRIDAY. GOOD
MIXING IN THE LOW LEVELS WILL CONTINUE TO BRING FREQUENT 25 KNOT
WIND GUSTS TO THE NEARSHORE WATERS DURING THIS TIME. SURFACE
PRESSURE GRADIENT WEAKENS LATER TONIGHT...WHICH SHOULD ALLOW WINDS
TO FALL BELOW SMALL CRAFT ADVISORY CRITERIA. HIGH WAVES OF 3 TO 6
FEET SHOULD BE CONFINED TO THE OPEN WATERS WITH THE OFFSHORE FLOW.
THESE WAVES WILL SUBSIDE WITH THE WEAKENING WINDS LATER TONIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CST FRIDAY FOR LMZ643>646.
&&
$$
SHORT/LONG TERM...13/MRC
AVIATION/MARINE...08/WOOD
