FXUS61 KRLX 070936
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
436 AM EST MON DEC 7 2009
.SYNOPSIS...
WEAK FRONT WITH LIMITED MOISTURE TODAY. WARM FRONTAL PRECIPITATION
TUESDAY AFTERNOON AND NIGHT. STRENGTHENING LOW PRESSURE LIFTS
NORTHEAST INTO GREAT LAKES WEDNESDAY WITH FRONT PASSING.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE THIS MORNING AS A
SHORTWAVE...CURRENTLY MOVING INTO IL...APPROACHES THE REGION. THIS
SHORTWAVE...AND ASSOCIATED WEAK FRONTAL BOUNDARY...HAS GENERATED
LIGHT SNOW SHOWERS ACROSS MUCH OF CENTRAL IL OVERNIGHT...WITH RAIN
IN KY AND AREAS SOUTH. THIS SHORTWAVE WILL SHEAR APART AS IT MOVES
INTO THE OHIO VALLEY THIS MORNING...WITH MOISTURE BECOMING LIMITED
AS IT DOES SO. MODEL SOUNDINGS INDICATE PRECIPITATION IN THE FORM OF
RAIN ACROSS MOST OF THE FORECAST AREA TODAY...EXCEPT FOR A BRIEF
PERIOD OF SNOW SHOWERS OR A RAIN/SNOW MIX THIS MORNING OVER SE
OHIO...BEFORE CHANGING TO ALL RAIN LATER THIS MORNING. MOUNTAIN
ZONES WILL SEE SNOW OR A RAIN/SNOW MIX AT ELEVATIONS ABOVE 2000
FEET...CHANGING TO ALL SNOW LATER IN THE EVENING. WITH OVERALL LACK
OF DEEP MOISTURE...ANY PRECIPITATION THAT DOES OCCUR WILL BE
LIGHT...GENERALLY LESS THAN A TENTH OF AN INCH. PRECIPITATION WILL
TAPER OFF ACROSS THE CWA TONIGHT AS THE SHORTWAVE AND ASSOCIATED
FRONTAL BOUNDARY CONTINUE TO MOVE EAST. HOWEVER...A FEW UPSLOPE
SHOWERS WILL CONTINUE TO PERSIST TONIGHT OVER THE HIGHER
TERRAIN...IN THE WESTERLY FLOW ALOFT.
TUESDAY MORNING LOW TEMPS A BIT TRICKY TO FORECAST FOR AS AMOUNT OF
CLEARING WILL BE SOMEWHAT OF A DETERMINING FACTOR...BUT THINKING
ENOUGH CLOUD COVER SHOULD BE STREAMING IN IN ADVANCE OF THE NEXT
SYSTEM...IN ADDITION TO GOOD SOUTHWESTERLY FLOW...TO NOT ALLOW FOR
TOO GREAT OF A DIP IN TEMPERATURE. HAVE KEPT LOW TEMPS GENERALLY IN
THE UPPER 20 TO LOWER 30 FORECAST RANGE AS A RESULT. SEVERAL OF THE
MODELS ALSO INDICATE SOME LIGHT PATCHY FOG FORMING TOMORROW MORNING.
THIS CERTAINLY IS NOT OUT OF THE QUESTION CONSIDERING THE MOIST
BOUNDARY LAYER FROM RECENT SNOWFALL...AND WILL DEPEND ON THE AMOUNT
OF CLEARING.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
STRONG SHORT WAVE TROUGH THAT DIGS INTO NEVADA TODAY IS THE WEATHER
STORY THIS PERIOD. MODELS APPEAR A BIT FASTER WITH ITS APPROACH TO
FCST AREA TUE. PRECIPITATION SHOULD BREAK OUT AND SPREAD ACROSS
THE AREA QUICKLY TUE IN RESPONSE TO STRONG WARM ADVECTION /
ISENTROPIC LIFT COUPLED WITH GOOD UPPER LEVEL DIVERGENCE.
PRECIPITATION CONTINUES WELL INTO TUE NT UNTIL OCCLUSION SWEEPS
THROUGH EARLY WED MORNING.
COLD AIR DAMMING PER STRONG AGEOSTROPHIC FLOW IN THE SYNOPTIC SCALE
SE FLOW REGIME AHEAD OF THE SYSTEM WILL LIKELY LEAD TO FREEZING RAIN
ON THE EASTERN MOUNTAIN SLOPES FOR A TIME LATE TUE AND TUE EVE.
THE POTENTIAL FOR THIS IS A BIT LIMITED BY THE ITS AFTERNOON
ARRIVAL. IT APPEARS THIS MAY BE AN ADVISORY LEVEL EVENT AT BEST.
IN THE STRONG PRESSURE GRADIENT...STRONG WINDS ARE LIKELY TUE NIGHT
THAT MAY REQUIRE AN ADVISORY FOR GUSTS INTO THE 40S ON THE RIDGES
AND OVERTOP OF THE LOW LEVEL COLD AIR TRAPPED IN THE MOUNTAIN
VALLEYS. WILL HAVE TO WATCH THIS INTO WED MORNING WHEN OCCLUSION
PROVIDES MUCH BETTER MIXING AND DOWNWARD MOMENTUM TRANSPORT BEFORE
50KT H85 FLOW ABATES WED AFTN.
WILL CONTINUE MENTION OF BOTH HAZARDS ONGOING IN THE HWO AS WELL AS
THEIR RESPECTIVE IMPACTS IN THE RWS.
A MUCH COLDER WEATHER REGIME FOLLOWS IN THE WAKE OF THIS STRONG
SYSTEM THROUGH THE BALANCE OF THIS PERIOD WITH THE COLD AIR ARRIVING
WED. UPSLOPE RAIN SHOWERS WED WILL GO TO SNOW SHOWERS BY LATE IN
THE DAY THAT THEN CONTINUE INTO THURSDAY. DRIER AIR SHOULD TAKE
HOLD THURSDAY NIGHT.
LIKE THE LOW SIDE OF GUIDANCE IN THE STABLE DECEMBER REGIME FOR
HIGHS TUE. TEMPERATURES WILL BE NON DIURNAL TUE NIGHT AND WED AS IT
WARMS IN ADVANCE OF THE SYSTEM TUE NT AND THEN COOLS BACK DOWN WED
AFTN. THE MEX DID NOT APPEAR TO BE PICKING UP ON MUCH LOWER
TEMPERATURES ITS SOURCE MODEL SUGGESTS FOR THU AND THU NT.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
STRONG LOW PRESSURE LIFTS RAPIDLY THRU THE GREAT LAKES AND NEW
ENGLAND AT THE START OF THE PERIOD. STRONG COLD ADVECTION RAPIDLY
OVERSPREADS THE ENTIRE AREA WEDNESDAY EVENING...WITH ANY RAIN
SHOWERS CHANGING TO SNOW SHOWERS. DO NOT EXPECT MUCH OF A POST
FRONTAL WRAPAROUND SNOW EVENT OR EVEN A SIGNIFICANT UPSLOPE EVENT
WEDNESDAY NIGHT. FLOW AROUND THE DEPARTING LOW REMAINS MORE WESTERLY
WITH DEEPER MOISTURE REMAINING TO OUR NORTH. THUS...EXPECT LITTLE OR
NO SNOW ACCUMULATION IN MOST OF THE LOWLANDS...WHILE GENERALLY
LIGHT SNOW ACCUMULATIONS ARE EXPECTED IN THE NORTHERN AND CENTRAL
MOUNTAINS. THE BIGGER FACTOR WEDNESDAY NIGHT MAY BE THE GUSTY WEST
WINDS IN THE TIGHT PRESSURE GRADIENT AROUND THE LOW...ESPECIALLY
OVER SOUTHEAST OHIO AND THE HIGHER ELEVATIONS OF THE NORTHERN
MOUNTAINS. GOING A BIT COLDER THAN MOS GUIDANCE...GIVEN THE STRONG
850/950MB COLD ADVECTION.
FOR THURSDAY...HIGH PRESSURE BUILDS IN WITH LINGERING MOUNTAIN SNOW
SHOWERS RAPIDLY ENDING...WITH DECREASING CLOUDS IN THE WEST. HIGH
PRESSURE OVER THE AREA THURSDAY NIGHT WITH IDEAL RADIATIONAL
COOLING...AGAIN GOING BELOW GUIDANCE TEMP MINS.
ANOTHER MUCH WEAKER SYSTEM IN THE STRONG WESTERLY FLOW IS PROGGED TO
PASS SOUTH OF OUR AREA AROUND THE BEGINNING OF THE WEEKEND. GOING
WITH THE FASTER AND MORE SUPPRESSED GFS...WHICH MAY GIVE THE AREA A
LIGHT RAIN OR SNOW EVENT LATER FRIDAY NIGHT INTO SATURDAY
MORNING.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
06Z MONDAY THROUGH 06Z TUESDAY...
MAINLY VFR CONDITIONS EXPECTED TONIGHT WITH ONLY SCATTERED TO BROKEN
HIGH CLOUDS. SOME PATCHY MVFR FOG IS POSSIBLE...ESPECIALLY NEAR
KEKN...BUT NO WIDESPREAD RESTRICTIONS TO VSBY ARE EXPECTED. VFR
CONDITIONS WILL CONTINUE ON MONDAY...ALTHOUGH CEILINGS WILL THICKEN
AND LOWER AS A WEAK FRONT APPROACHES THE REGION. THIS WILL GENERATE
LIGHT RAIN SHOWERS ON MONDAY...CHANGING TO SNOW OR A RAIN/SNOW MIX
AFTER 21Z...MAINLY OVER THE HIGHER TERRAIN. LIGHT SE SURFACE WINDS
WILL VEER DURING THE DAY MONDAY AS THE WEAK FRONTAL BOUNDARY
APPROACHES THE REGION. MODERATE TO STRONG WESTERLY WINDS ALOFT.
AFTER 06Z TUESDAY...
IFR IN MOSTLY RAIN LATE TUESDAY INTO WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...SL/TRM
NEAR TERM...SL
SHORT TERM...TRM
LONG TERM...JMV
AVIATION...SL
