FXUS61 KILN 302336
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
636 PM EST MON NOV 30 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN SOUTH OF THE REGION OVERNIGHT...
REMAINING IN PLACE THROUGH TUESDAY. ON WEDNESDAY...AN AREA OF LOW
PRESSURE WILL MOVE INTO THE OHIO VALLEY FROM THE SOUTH.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW LEVEL MOISTURE WILL SLOWLY WORK ITS WAY EAST OF THE REGION
OVERNIGHT. CLOUDS ARE STARTING TO SCATTER OUT A LITTLE BIT
ALREADY. SURFACE HIGH PRESSURE WILL BUILD IN FROM THE
WEST...BECOMING CENTERED TO THE SOUTH OF THE ILN CWA.
JUST A DEGREE OR TWO ABOVE GUIDANCE CONSENSUS FOR LOWS OVERNIGHT...
WITH WINDS STAYING UP AND A FEW CLOUDS DEPARTING THE REGION.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
NOT MUCH TO SPEAK OF ON TUESDAY...WITH HIGH PRESSURE TO THE SOUTH
AND SOME MODEST SOUTHWESTERLY FLOW. CLOSE TO GUIDANCE FOR HIGHS.
AN AREA OF LOW PRESSURE DEVELOPING NEAR THE GULF COAST WILL BE THE
MAIN CONCERN FOR THIS PERIOD OF THE FORECAST. A SHARP 500MB TROUGH
WILL PULL A LOW UP THE MISSISSIPPI RIVER AND THEN INTO THE OHIO
VALLEY BY WEDNESDAY NIGHT. MODEL TIMING HAS COME INTO PRETTY GOOD
AGREEMENT...WITH DIFFERENCES MAINLY IN PLACEMENT. THE NAM IS
FURTHEST WEST...BRINGING THE LOW UP THROUGH INDIANA...WHILE THE
GFS AND ECMWF TAKE IT FURTHER EAST INTO PENNSYLVANIA. THE GEM IS A
GOOD COMPROMISE OF THE TWO AND GENERALLY STUCK CLOSE TO IT.
HAVE INCLUDED SOME PRETTY HIGH POPS...WITH THE BEST CHANCE FOR
GOOD RAINFALL COMING IN THE STRONG ISENTROPIC LIFT AHEAD OF THE
LOW. LINGERING MOISTURE WILL LEAD FOR A CHANCE OF MORE SPOTTY
SHOWERS CONTINUING THROUGH WEDNESDAY NIGHT INTO THURSDAY MORNING.
TEMPS ON WEDNESDAY NIGHT WERE A BIT TRICKY WITH A NON-DIURNAL
CURVE IN THE FORECAST. GOOD AGREEMENT ON A SURGE OF HIGHER THETA-E
AIR RIDING AT LEAST INTO THE SOUTHWEST CORNER OF THE FORECAST
AREA...AND SURFACE TEMPERATURES IN THIS AREA MAY PEAK OUT AFTER
SUNSET. AFTERWARDS...THE COLD FRONT WILL PUSH THROUGH BY SUNRISE
THURSDAY...LEADING TO SHARPLY FALLING TEMPERATURES WITH COLD
ADVECTION.
BECAUSE OF THE COLD ADVECTION...PROFILES LOOK COLD ENOUGH FOR A
TRANSITION TO SNOW IN THE WESTERN PORTION OF THE FORECAST AREA.
WITH ONLY SPOTTY PRECIPITATION AROUND AT THAT TIME...DO NOT EXPECT
APPRECIABLE ACCUMULATIONS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
LATEST MODELS A BIT WARMER WITH SYSTEM TO MOVE THROUGH MIDWEEK. GFS
AND ECMWF SIMILAR WITH LOCATION OF SURFACE LOW ACROSS NY STATE BY
12Z THU MORNING. GFS CONTINUES TO BE MORE PROGRESSIVE WITH MOVEMENT
OF UPPER LEVEL TROF THU AND FRI THAN ECMWF. FORECAST WILL TREND
TOWARD SLOWER ECMWF. DEEP UPPER LEVEL TROF WILL SETTLE INTO THE
GREAT LAKES ON THU. FORECAST AREA WILL SEE CHANCE OF SNOW SHOWERS IN
THE MORNING WITH A CHANCE OF SEEING SOME RAIN SHOWERS FOR A BRIEF
PERIOD IN THE AFTERNOON BEFORE CHANGING BACK TO A CHANCE OF SNOW
SHOWERS. ANY SCATTERED SNOW SHOWERS WILL END LATE FRI AFTERNOON. AS
SURFACE RIDGING WILL BUILD INTO THE OHIO VALLEY.
MODEL SOLUTIONS SHOW A LARGE DIVERGENCE THIS WEEKEND WITH ECMWF
MAINTAINING THE UPPER LOW OVER THE GREAT LAKES WHILE THE GFS IS MORE
PROGRESSIVE. WILL FOLLOW SOLUTION CLOSER TO ECMWF WITH CONTINUED
COLD TEMPERATURES. TEMPERATURES IN THE EXTENDED PERIOD MAY BE SOME
OF THE COLDEST SO FAR THIS YEAR. AT THIS TIME...WILL KEEP DRY
CONDITIONS AFTER FRIDAY. HOWEVER...FORECAST AREA MAY SEE A FEW
SHOWERS SAT OR SUN IF THE SLOWER ECMWF TRACK OF THE UPPER LOW
VERIFIES.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL REMAIN ACROSS THE REGION THROUGH THE TAF PERIOD.
VFR CONDITIONS CAN BE EXPECTED.
OUTLOOK...MVFR/IFR CIGS/VSBYS POSSIBLE WITH PRECIPITATION WEDNESDAY
NIGHT INTO THURSDAY. MVFR CIGS POSSIBLE ON FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...PARKER
AVIATION...HICKMAN
