Issued by NWS Grand Rapids, MI
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000 FXUS63 KGRR 291535 AFDGRR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1135 AM EDT WED OCT 29 2008 LATEST UPDATE...SYNOPSIS/SHORT TERM... .SYNOPSIS...(1135 AM EDT WED OCT 29 2008) CLOUDS WILL PERSIST THROUGH MUCH OF THE AFTERNOON WITH HIGH TEMPERATURES IN THE 40S. AS HIGH PRESSURE BUILDS IN OVER THE NEXT FEW DAYS...TEMPERATURES WILL WARM UP. A WEAK COLD FRONT WILL PASS THROUGH ON HALLOWEEN...BUT FAIR WEATHER SHOULD PREVAIL WITH HIGHS AROUND 60 DEGREES. && .SHORT TERM...(1135 AM EDT WED OCT 29 2008) (TODAY THROUGH FRIDAY) MADE SOME TWEAKS TO CLOUD COVER AND WINDS. MODEL AND OBSERVED SOUNDINGS...AS WELL AS SATELLITE IMAGERY...SHOW POTENTIAL FOR STRATUS DECK TO HANG ON MUCH OF THE AFTERNOON. SOUNDINGS HAVE STRONG INVERSION AROUND 800 TO 700 MB WHICH IS PROGGED TO HANG ON THROUGH THE AFTERNOON...SO LITTLE IN THE WAY OF MIXING WILL BE POSSIBLE. LAKE SUPERIOR CONNECTION IN NW FLOW IS ALSO PROVIDING ENOUGH MOISTURE TO KEEP SOUTHWEST LOWER MICHIGAN IN THE CLOUDS FOR A WHILE. SO WENT MOSTLY CLOUDY FOR THE REST OF THE DAY AND DECREASED THE WIND GUSTS A BIT DUE TO THE LACK OF DEEP MIXING. REST OF PREVIOUS FORECAST DISCUSSION FOLLOWS. A SURFACE RIDGE SETTLES IN TONIGHT. THE WINDS WILL DECOUPLE EARLY TONIGHT AND TEMPS WILL QUICKLY DROP BELOW FREEZING. HOWEVER...A LIGHT SOUTHERLY WIND SHOULD DEVELOP AFTER MIDNIGHT WHICH SHOULD HOLD TEMPS NEARLY STEADY FOR THE REMAINDER OF THE OVERNIGHT PERIOD. LOWS SHOULD BOTTOM OUT FROM 25 TO 30 IN MOST LOCALES. WE WILL BE MUCH WARMER THURSDAY AND THURSDAY NIGHT WITH ABOVE NORMAL TEMPS AS SSW WINDS PULL IN AN AIR MASS FROM THE SOUTHERN PLAINS. HIGHS WILL BE WELL INTO THE 50S WITH LOWS MAINLY IN THE 40S. THE MODELS ARE IN VERY GOOD AGREEMENT SHOWING A WEAK COLD FRONT DROPPING ACROSS THE UPPER MIDWEST AND INTO LOWER MICHIGAN BY LATE IN THE DAY. THE CHANCES OF PCPN WILL NOT BE ZERO AS THERE IS A SLIGHT WEAKNESS IN THE INSTABILITY. HOWEVER...THE FRONT WILL LACK MOISTURE AND THE INSTABILITY APPEARS TOO BORDERLINE TO ADD POPS TO THE NORTHERN CWA. WITH THE FRONT NOT MOVING IN UNTIL CLOSE TO EVENING WE WILL BE ABLE TO WARM INTO THE 60 TO 65 DEGREE RANGE. && .LONG TERM...(344 AM EDT WED OCT 29 2008) (FRIDAY NIGHT THROUGH TUESDAY) SHALLOW COLD AIR ADVECTION ARRIVES FRIDAY EVENING AND LASTS INTO SATURDAY. THE NORTHEASTERLY FLOW WILL DRAW DOWN A STABLE AIRMASS FROM ONTARIO. LIMITED MIXING HEIGHTS ON SATURDAY SHOULD KEEP OUR TEMPERATURES SLIGHTLY BELOW NORMAL. TROUGHING DEVELOPS IN THE WRN U.S. FOR SUN INTO TUE...AND THAT WILL LEAD TO RIDGING EAST OF THE ROCKIES. THE DEVELOPING SOUTHERLY FLOW WILL WARM UP OUR TEMPERATURES...TO WELL ABOVE NORMAL LEVELS. AS FOR RAIN...WILL NEED TO MONITOR SUN EVENING WITH A WARM FRONT LIFTING THROUGH THE REGION. THE RECENT RUN OF THE HI RES EURO SHOWS A RATHER MOIST PROFILE WITH THE FRONT. THE GFS IS CONSIDERABLY DRIER. AT THIS POINT I WILL MAINTAIN A DRY FORECAST. && .MARINE...(344 AM EDT WED OCT 29 2008) BRISK NORTHWEST WINDS WILL CONTINUE TODAY KEEPING THE LAKE CHURNED UP. THE WINDS AND WAVES WILL DIMINISH THIS EVENING AS THE SURFACE RIDGE MOVES IN. HAVE EXTENDED THE SMALL CRAFT ADVISORY BY A FEW HOURS TO ACCOUNT FOR THE DELAYED REACTION IN THE WAVES ACTION SUBSIDING. THIS BREAK IN LOWER WAVES WILL ONLY LAST ABOUT 12 HOURS AS SOUTHERLY WINDS ON THE BACKSIDE OF THE HIGH BEGIN TO STIR UP THE LAKE ONCE AGAIN BY THURSDAY AFTERNOON. IN FACT IT APPEARS THAT WINDS MAY APPROACH GALE FORCE ACROSS CENTRAL LAKE MICHIGAN BY MID AFTERNOON INTO EARLY THURSDAY NIGHT. && .AVIATION...(744 AM EDT WED OCT 29 2008) A VFR CLOUD DECK WILL SPREAD SOUTHWARD THROUGH THE REGION BY 13Z AND PERSIST ACROSS THE AREA THROUGH 18Z. WINDS ARE EXPECTED TO BECOME GUSTY BY NOON. SKIES WILL CLEAR FROM WEST TO EAST THIS EVENING AS THE UPPER LOW PULLS AWAY. && .HYDROLOGY...(1135 AM EDT WED OCT 29 2008) RIVERS SHOULD CONTINUE TO REMAIN STEADY OR SLOWLY FALL AS NO SIGNIFICANT PRECIPITATION IS EXPECTED OVER THE NEXT FEW DAYS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY IN EFFECT THROUGH THIS EVENING FROM ST. JOSEPH TO MANISTEE. && $$ SYNOPSIS: OSTUNO SHORT TERM: OSTUNO LONG TERM: MJS MARINE: JK AVIATION: MJS HYDROLOGY: OSTUNO
