000
FXUS61 KCLE 280425
AFDCLE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
1125 PM EST MON DEC 27 2010
.SYNOPSIS...
HIGH PRESSURE OVER THE LOWER OHIO VALLEY WILL MOVE TO THE
SOUTHEAST STATES AND BECOME NEARLY STATIONARY WHICH WILL GRADUALLY
BRING WARMER AIR INTO THE AREA.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW LEVEL FLOW IS BACKING AND QUITE A BIT OF SHEAR IN THE BOUNDARY
LAYER NOW MOVING IN FROM THE WEST. WARM ADVECTION IS INCREASING AS
WELL. THE REMAINING FLURRIES ACROSS EXTREME NE OH/NW PA WILL END
OVERNIGHT. DIFFERENTIAL ADVECTION ALOFT WILL CONTINUE TO BRING
PATCHES OF MID/HIGH CLOUDS ESPECIALLY ACROSS NE OH/NW PA. WILL NOT
REALLY BE ABLE TO DEPICT THE CLOUD COVER VERY WELL IN THE GRAPHICS
AND WILL SIMPLY COVER IT WITH "VARIABLE CLOUDINESS" IN THE ZONE
FORECAST. THE GUIDANCE AND CURRENT FORECAST IS A LITTLE STRONG
WITH THE ACTUAL WIND BUT WE WILL PROBABLY NOT GO CALM OVERNIGHT
EXCEPT FOR PROTECTED AREAS DOWN TOWARD ROUTE 30 ON SOUTH...SO
TEMPERATURES WILL NOT BOTTOM OUT AS LOW AS THEY COULD
GO. THAT BEING SAID...THEY WILL BE COLDER THAN THE CURRENT
FORECAST BY A FEW DEGREES. WILL USE A RANGE OF 10 TO 15 FOR MOST
AREAS AS A GOOD BALLPARK ESTIMATE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
A WARMING TREND IS EXPECTED DURING THIS PERIOD AS THE SURFACE
RIDGE BECOMES STATIONARY OVER THE MID ATLANTIC STATES AS THE UPPER
AIR PATTERN CHANGES TO RIDGING IN THE EAST. GENERALLY FAIR UNTIL
PERHAPS LATE WEDNESDAY NIGHT AND THURSDAY WHEN A WEAK SHORT WAVE
ALOFT MAY SPREAD SOME LIGHT PRECIPITATION INTO THE WESTERN
COUNTIES. LIGHT FREEZING RAIN IS POSSIBLE LATE WEDNESDAY NIGHT BUT
CONFIDENCE IS LOW NOW SO WE WILL NOT MENTION IT IN THE FORECAST.
TEMPERATURES WILL RISE ABOVE FREEZING FOR THURSDAY SO ANY
PRECIPITATION WILL BE LIQUID AT THAT TIME.
HAVE USED MAV GUIDANCE WITH SOME LOWERING OF TEMPERATURES TO REFLECT
SHALLOW INVERSION CURRENTLY IN PLACE ACROSS THE MIDWEST ALONG WITH
SNOW COVER.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE EXTENDED PERIOD BEGINS FRIDAY WITH THE ECMWF AND GFS IN
REASONABLY GOOD AGREEMENT. MODELS SHOW AN UPPER RIDGE ACROSS THE
EASTERN THIRD OF THE NATION WITH A LARGE SURFACE HIGH CENTERED ALONG
THE NC/VA COAST. DEEP SOUTHERLY FLOW OFF THE GULF OF MEXICO THROUGH
THE MISSISSIPPI VALLEY INTO THE OHIO VALLEY. MODELS DIFFER A BIT ON
MID LEVEL RH BUT SINCE THE AREA WILL BE SOLIDLY WITHIN THE WARM
SECTOR WOULD EXPECT AT LEAST PEEKS OF SUNSHINE. WITH THE DEEP MOIST
FLOW HOWEVER THAT WILL NOT LAST SO FRIDAY NIGHT WENT TO 100% CLOUDS
AS A STRONG COLD FRONT APPROACHES. DEEP MOISTURE MOVES IN FRIDAY
NIGHT AND WITH TEMPS EVEN AT 850MB WELL ABOVE 00Z WILL GO WITH RAIN
AND LIKELY POPS. THIS WILL LAST INTO SATURDAY PRE FRONT. THE FRONT
WILL MOVE THROUGH THE AREA SATURDAY MORNING AND EARLY AFTERNOON.
POST FRONT SATURDAY EVENING DRY AIR...SUBSIDENCE AND SURFACE RIDGING
MOVE IN SO HAVE WENT WITH A 6 HOUR PERIOD OF DRY CONDITIONS. AS
SATURDAY NIGHT WEARS ON HOWEVER COLDER AIR WILL FILL IN ACROSS THE
AREA. WINDS ACROSS THE LAKE WILL BE WSW AND BY SUNDAY MORNING COULD
BEGIN TO SEE SNOW SHOWERS OFF THE LAKE INTO NERN OHIO AND NWRN PA.
GFS COLDER THAN THE ECMWF HERE AT THIS TIME AT -12C AT 850 VC -7C
OVER THE LAKE. WILL CONTINUE SNOW SHOWERS SUNDAY AND SUNDAY NIGHT
OFF THE LAKE INTO THE SNOW BELT. DRY ELSEWHERE. TEMPS WELL ABOVE
NORMAL TO START BUT END UP NEAR NORMAL BY MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
CLEARING HAS PROGRESSED TO NEARLY THE OH/PA BORDER. BUT...AS
FEARED...AN AREA OF IFR STRATUS CONTINUES TO MOVE TOWARD THE AREA
FROM THE WEST AND SW. WILL TRY TO TIME THESE CLOUDS ACROSS THE
AREA OVERNIGHT AS IT DOESN'T LOOK LIKE IT WILL DISSIPATE. STILL
EXPECTING SW FLOW TO PICK UP AGAIN TOWARD MORNING. AS THAT
HAPPENS...ENOUGH MIXING WILL OCCUR TO START TO CAUSE THE CIGS TO
LIFT AND DISSIPATE. MOST AREAS SHOULD BE VFR BY MIDDAY TUESDAY AND
IT IS POSSIBLE THAT WESTERN AREAS COULD BE VFR BY 12Z.
OUTLOOK...NON VFR POSSIBLE THURSDAY NIGHT THROUGH EARLY SATURDAY.
&&
.MARINE...
SMALL CRAFT CONDITIONS WILL CONTINUE INTO WEDNESDAY. AS THE DEEP
COASTAL LOW PULLS AWAY AND HIGH PRESSURE WORKS ITS WAY INTO THE OHIO
VALLEY...WINDS ACROSS LAKE ERIE WILL SWITCH FROM NORTHWEST TO WEST
AND SOUTHWEST BY TUESDAY. THE GRADIENT THOUGH WILL STILL BE SOMEWHAT
TIGHT TONIGHT AND TOMORROW SO WINDS TO 30 KNOTS WILL BE POSSIBLE.
AFTER THAT A DIMINISHING TREND AS A RIDGE BECOMES ESTABLISHED
SOUTHEAST OF THE LAKE. THIS WILL PROVIDE FOR A PROLONGED PERIOD OF
SOUTHERLY FLOW FROM WEDNESDAY NIGHT INTO FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST WEDNESDAY FOR LEZ144>149.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KOSARIK
SHORT TERM...REL
LONG TERM...TK
AVIATION...KUBINA
MARINE...OUDEMAN
