####018002740#### FXUS63 KIND 080451 AFDIND AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 1150 AM EST SUN FEB 8 2009 .AVIATION...DISCUSSION FOR 06Z TAFS. SURFACE COLD FRONT WILL CROSS INDIANA DURING THE FIRST SIX HOURS OF THE TAF AND WINDS WILL SHIFT TO NORHTWEST BY AROUND 10-12Z. UPSTREAM CONDITIONS SHOW MVFR CIGS THAT WILL ARRIVE BY THAT TIME AS WELL. HOWEVER THIS SHOULD BE SHORT LIVED AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT AND BRINGS VFR SKIES AND LIGHT WINDS FOR THE REST OF THE TAF PERIOD AFTER 15Z SUNDAY. && .PREVIOUS DISCUSSION... FCST ISSUES REMAIN TEMPS AND PRECIP CHCS/AMOUNTS INTO NEXT WEEK. 18Z SFC MAP SHOWS 998MB SFC LOW ACROSS ONTARIO WITH A COLD FRONT DEVELOPING ACROSS IA/KS. LOW LEVEL LIFT AND MOISTURE ADVECTION HAS LEAD TO STRATUS ACROSS PARTS OF CENTRAL IN TODAY WHILE CLEAR SKIES WERE OCCURRING ACROSS CENTRAL IL IN THE WARM SECTOR. SFC DEWPOINTS UPSTREAM ACROSS MO REMAIN IN THE LOWER 50S. PREFER A BLEND OF MOS TEMPS IN THE NEAR/FIRST 48HRS GIVEN COLD BIAS OF BUFKIT FCST SOUNDING TEMPS. TONIGHT...SHALLOW LIFT AND MOISTURE ADVECTION MAY LEAD TO AREAS OF DZ OR SCT LIGHT SHOWERS AHEAD OF THE FRONT. LIFT IS SHALLOW SO WE WILL UNDERCUT MOS POPS TONIGHT. AIR TEMPS WILL REMAIN MILD UNTIL THE FRONT PASSES AFTER 06Z WHEN TEMPS SHOULD DROP BACK INTO THE 30S. WILL NOT INCLUDE FOG AT THIS POINT GIVEN LOW CLDS THAT SHOULD PERSIST AHEAD OF THE FRONT. SUN...ANY EARLY CLOUDS SHOULD GIVE WAY TO SUN BY MIDDAY AS A 1030MB HIGH SHIFTS OUT OF THE NORTHERN ROCKIES INTO THE MS VALLEY. AT THIS POINT WE WILL KEEP HIGHS A BLEND OF THE COLDER MET AND WARMER MAV MOS TEMPS WITH SOME REMAINING SNOW COVER AND NE WINDS. SUN NIGHT-MON...DRY CONDS WILL PERSIST WITH ALL MODELS NOW SLOWING THE FIRST SYSTEM DOWN AND THIS TREND MAKES SENSE GIVEN THAT THE LOW IS CUTOFF ACROSS THE SW. HIGHS MON SHOULD AGAIN BE MILD BUT WILL KEEP HIGHS NEAR THE COOLER GUIDANCE WITH EXPECTED INCREASE IN CLDS. FIRST WAVE OF PRECIP IS STILL EXPECTED LATE MON NIGHT INTO TUES WHEN AROUND 0.25 TO 0.75 OF AN INCH IS FCST BY MODELS TO FALL. THE 12Z GFS CONTINUES TO FCST A STRONGER SYSTEM TO APPROACH THE AREA TUES NIGHT WITH MORE WIDESPREAD RAIN EXPECTED THROUGH WEDS. ECMWF AND GFS ENSEMBLE FCST THE LOW WITH THIS STRONGER SECOND SYSTEM TO TRACK JUST NW OF THE CWA WEDS HOWEVER THIS IS STILL TOO FAR OUT TO CALL SO WE CANNOT CALL THE LOCATION OF THE HEAVIEST RAINS THIS FAR OUT BUT IT STILL APPEARS THAT MOST AREAS WILL RECEIVE ANOTHER 1 TO 2 INCHES WITH THE SECOND STORM. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...JAS AVIATION...JOHNSON ####018004293#### FXUS63 KGRR 080453 AFDGRR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1153 PM EST SAT FEB 7 2009 LATEST UPDATE...AVIATION... .SYNOPSIS...(327 PM EST SAT FEB 7 2009) A COLD FRONT WILL MOVE THROUGH TONIGHT AND HIGH PRESSURE WILL BRING FAIR AND COOLER WEATHER FOR SUNDAY. THE FAIR WEATHER WILL PERSIST INTO MONDAY BUT LOW PRESSURE WILL BRING SOME RAIN FOR MONDAY NIGHT. A STRONGER LOW PRESSURE CENTER WILL ARRIVE FOR WEDNESDAY NIGHT AND BRING SOME HEAVY RAIN...CHANGING TO SNOW BEFORE IT ENDS ON THURSDAY. && .SHORT TERM...(327 PM EST SAT FEB 7 2009) (TONIGHT THROUGH MONDAY NIGHT) DRY COLD FRONT COMES THROUGH TONIGHT AND BUBBLE SFC HIGH BRINGS A NICE DAY ON SUNDAY...ALTHOUGH TEMPS WILL BE ABOUT TEN DEGREES COOLER THAN TODAY. SFC HIGH MOVES EAST ON MONDAY...BUT MODEL TRENDS SUGGEST ANY PRECIP WILL HOLD OFF UNTIL MONDAY EVENING. DROPPED POPS FOR MONDAY AFTERNOON. SFC LOW TRACKS WELL WEST OF LOWER MICHIGAN...BUT DEEP MOISTURE AND ISENTROPIC ASCENT WILL ALLOW FOR SOME RAIN MONDAY NIGHT. QPF WITH THIS SYSTEM SHOULD BE RELATIVELY LIGHT. && .LONG TERM...(327 PM EST SAT FEB 7 2009) (TUESDAY THROUGH SATURDAY) AN ACTIVE WEATHER PATTERN IS SHAPING UP NEXT WEEK. WINTER IS CERTAINLY GOING TO HANG ON BUT WE/RE GOING TO BE EXPERIENCING WARM AIR INTRUSIONS TOO. TUESDAY LOOKS WARM IN SOUTHWEST FLOW AHEAD OF ANOTHER LOW THAT WILL DEVELOP IN THE PLAINS AND MOVE NORTHEAST. BOTH THE ECMWF AND GFS TAKE THE LOW INTO LOWER MICHIGAN WEDNESDAY. THAT WILL MEAN RAIN FOR THE REGION. BUFKIT SHOWS OVER 2 INCHES OF RAIN FALLING DURING THE MIDDLE OF THE WEEK. THAT MUCH RAIN WOULD LIKELY RESULT IN SOME FLOODING ACROSS THE REGION...ALTHOUGH LIKELY NOT AS BAD AS THE FLOODING DURING THE END OF DECEMBER. THE REASON IS THAT WE/LL HAVE A FEW DAYS OF WARM WEATHER LEADING UP TO IT AND PROBABLY WON/T MELT A FOOT OF SNOW IN A DAY LIKE WE DID IN DECEMBER. THUS THERE WILL BE MORE TIME FOR THE SNOW TO RUN OFF. IT/S SOMETHING WE/LL CONTINUE TO KEEP AN EYE ON. THUNDER MAY BE A POSSIBILITY TOO AHEAD OF THE LOW AS ELEVATED LI/S FALL TO AROUND 0C AND THETA-E DECREASES WITH HEIGHT. COOLER AIR...NOT ARCTIC...WILL MOVE BACK IN FOLLOWING THE RAIN ON WEDNESDAY. SOME LIGHT SNOW CAN BE EXPECTED ON THE BACK SIDE OF THE PCPN SHIELD. HOWEVER...H8 TEMPS DON/T LOOK LIKE THEY WILL BE COLD ENOUGH FOR LAKE EFFECT SNOW TO DEVELOP. DRY WX IS EXPECTED THEN THROUGH SATURDAY. THE ONLY CONCERN THERE IS LATE FRIDAY INTO SATURDAY. ECMWF/GFS BOTH SHOW A LOW MOVING EAST ACROSS THE OHIO VALLEY. THE GFS HAS TRENDED NORTH WITH THIS LOW. IF THE TREND CONTINUES...WE MAY NEED TO ADD SNOW TO THE GRIDS FOR SATURDAY. && .AVIATION...(1153 PM EST SAT FEB 7 2009) A COLD FRONT IS SAGGING SOUTH THROUGH SOUTHWEST LOWER MICHIGAN TONIGHT...WITH AN AREA OF MVFR CEILINGS BEHIND THE FRONT. THE AREA OF MVFR CEILINGS CONTINUES TO SLIDE SOUTH...STRETCHING FROM ABOUT WHITEHALL TO MOUNT PLEASANT AT 05Z. THE LOWER CEILINGS WILL GRADUALLY FILTER INTO ALL OF THE TAF SITES THROUGH 12Z OR SO. MODELS SCOUR OUT THE LOW CLOUDS FAIRLY QUICK ON SUNDAY MORNING...WITH VFR CONDITIONS PREVAILING THE REMAINDER OF THE TAF VALID TIME THROUGH 06Z TOMORROW NIGHT. LIGHT FOG IS NOT OUT OF THE QUESTION LATE TONIGHT...BUT OPTED TO JUST INCLUDE A 6SM AND HAZE AT THIS POINT. STILL FEEL THE WINDS JUST OFF THE SURFACE WILL PRECLUDE MUCH IN THE WAY OF FOG FORMATION. && .HYDROLOGY...(327 PM EST SAT FEB 7 2009) RIVERS WILL BE RISING DUE TO RUNOFF FROM THE EXTENSIVE SNOWMELT TODAY. THE GOOD NEWS IS THAT MOST OF THE SNOWPACK WILL BE GONE BY THE TIME IT ACTUALLY RAINS ON MONDAY NIGHT AND AGAIN WEDNESDAY. THIS WILL PRODUCE EXTENDED HIGH FLOWS ON AREA RIVERS BUT NOT THE VERY RAPID AND SHARP CRESTS THAT OCCURRED WITH THE RAIN AND SNOWMELT ON DECEMBER 27TH. HEAVY RAIN POTENTIAL EXISTS FOR WEDNESDAY NIGHT. THIS WOULD INCREASE ALREADY HIGH FLOWS AND CAUSE PROBLEMS WITH ICE JAM FLOODING. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS: OSTUNO SHORT TERM: OSTUNO LONG TERM: 93 AVIATION: DUKE HYDROLOGY: OSTUNO