FXUS61 KRLX 301033
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
533 AM EST MON NOV 30 2009

.SYNOPSIS...
COLD FRONT BRINGS RAIN SHOWERS TODAY...ENDING AS SNOW SHOWERS LATER 
TONIGHT. HIGH PRESSURE RETURNS TUESDAY.  LOW PRESSURE PASSES 
THURSDAY MORNING. COLDER THURSDAY NIGHT AND FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
LARGE SHIELD OF RAIN MOVING AHEAD OF AND ALONG A COLD FRONT TO THE 
NORTHWEST OF THE CWA WILL BRING STEADY LIGHT SHOWERS FOR THE BULK OF 
THE MORNING...AND WILL CLEAR NORTHWEST TO SOUTHEAST AS THE MORNING 
AND EARLY AFTERNOON PROGRESSES. ANTICIPATING A SHARP GRADIENT TO THE 
POPS ON THE BACK SIDE OF THE FRONT...AND THE CWA SHOULD CLEAR 
QUICKLY WITH THE SPEEDY EXIT OF THE BOUNDARY. THE UPPER LEVEL TROUGH 
FOLLOWS THIS AFTERNOON AND EVENING AS A BRIEF PERIOD OF NORTHWEST 
FLOW SETS UP. WITH POST FRONTAL PRECIPITATION OCCURRING IN THE 
HIGHER ELEVATIONS...TEMPERATURES WILL DROP...WITH AN EVENTUAL CHANGE 
OVER TO LIGHT SNOW ABOVE 2000FT. WILL NOT BE EXPECTING CONSEQUENTIAL 
ACCUMULATIONS. AS THE LOW LEVEL MOISTURE ERODES SLOWLY IN THE 
MOUNTAINS...THE WESTERN LOWLANDS WILL BECOME CLEAR OVERNIGHT. COULD 
SEE MID LEVEL CLOUDS SKIRT THE NORTHERN ZONES AFTER 00Z TUESDAY.

NON DIURNAL TEMPERATURE REGIME IN PLACE WITH THE COLD FRONT 
TODAY...AND WILL GENERALLY EXPERIENCE THE MAX TEMPERATURE SHORTLY 
AFTER DAWN. PINPOINTING THIS TIMING IS DIFFICULT...AND HELD THE MAX 
FOR THREE HOURS DURING THE MORNING. WITH PASSAGE OF THE COLD 
FRONT...THE AFOREMENTIONED TURN TO A NORTHWEST SURFACE FLOW WILL 
SLOWLY DROP TEMPERATURES ALL THE WAY INTO THE OVERNIGHT.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
SFC HIGH PRESSURE PROVIDES DRY WEATHER THROUGH TUESDAY NIGHT. PLENTY 
OF SUNSHINE WILL BRING MILD TEMPERATURES DURING THE DAY...BUT NEAR 
FREEZING TEMPERATURES TUE NIGHT INTO WED MORNING DUE TO RADIATIONAL 
COOLING. WENT WITH THE BIAS CORRECTED SREF FOR TEMPS THRU TUE NIGHT. 

A LOW PRESSURE SYSTEM DEVELOPS ALONG THE GULF OF MEXICO STATES 
WED...TRACKING NORTH NORTHEAST INTO THE TN VALLEY. THE GFS AND SREF 
HAVE SIMILAR TIMING OF THE ONSET OF PCPN REACHING SOUTHERN WV BY WED 
12Z...SPREADING NORTHEAST WITH TWO AREAS OF MAX PCPN...ONE ALONG THE 
EASTERN MOUNTAINS...THE OTHER ALONG SOUTHEAST OH. THE NAM AND ECMWF 
LAG ABOUT 6-12 HOURS...WITH BULK OF PCPN TARGETING SOUTHEAST OH AND 
LESS PCPN ACROSS THE EASTERN MOUNTAINS. ADJUSTED CATEGORICAL POPS 
WED NIGHT. 

MODELS SHOW MODERATE TO STRONG SOUTHERLY FLOW AT H8. THIS IMPLIES 
STRONG WARM ADVECTION PERHAPS NOT HANDLED WELL BY MODELS. 
THEREFORE...DECIDED TO GO FEW DEGREES WARMER THAN GUIDANCE FOR HIGH 
TEMPERATURES ON WED. IN ADDITION...INCREASE WIND GUSTS ON WED 
AFTERNOON AND NIGHT PER MOST MODELS SHOWING H8 WIND FROM 50 TO 70 
KNOTS. ALTHOUGH FLOW LOOKS UPGLIDING IN ISENTROPIC SFC...KEPT 
HIGHEST WIND GUSTS ALONG THE WESTERN SLOPES AND HIGHER RIDGES.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE STRONG WAVE MAY GO WEST OF THE MOUNTAINS THURSDAY MORNING. WILL 
BASE THIS FORECAST WITH HPC THINKING THAT THE RECENT RUNS GFS RUNS 
THROUGH 12Z WERE ON THE FAST SIDE OF THE ENVELOPE.  WILL GO ABOUT 6 
HOURS SLOWER FOR OUR DETERMINISTIC HOURLY GRAPHICS.

DESPITE THE SIGNIFICANT SE FLOW INTO OUR UPSLOPE...DO NOT THINK IT 
WILL BE COLD ENOUGH FOR ANY MIXED PCPN WEDNESDAY NIGHT.  HAVE ALL 
RAIN THEN.  DID INCREASE THE SURFACE WINDS FOR AOA 2000 FEET 
WEDNESDAY NIGHT.

WITH THAT TIMING...HAVE TEMPERATURES FALLING WEDNESDAY 
EVENING...THEN LEVELING OFF AND RISING DURING THE PREDAWN...THEN 
FALLING THURSDAY AFTERNOON.  SO A NONDIURNAL FOR BOTH WEDNESDAY 
NIGHT AND AGAIN ON THURSDAY.  HAVE THE RAIN CHANGING TO SNOW SHOWERS
THURSDAY AFTERNOON.  

WITH THE 500 MB TROF STILL HOLDING BACK OVER THE MIDWEST...TO OUR 
WEST...AND THE 850 THERMAL TROF STILL TO OUR WEST...WENT 
BELOW/COLDER THAN HPC GUIDANCE TEMPERATURES FOR FRIDAY INTO 
SATURDAY.  HAVE POPS HIGHER THAN HPC FOR UPSLOPE SNOW SHOWERS 
THURSDAY NIGHT INTO FRIDAY. ALSO...LOW LEVEL MOISTURE MAY ALSO 
LINGER LONGER...INTO SATURDAY...SO STILL HAVE SOME 20 POPS LINGERING 
IN MANY AREAS.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
MVFR DOMINATING...AND WILL BE MET WITH BRIEF IFR WITH CEILINGS
DROPPING PERIODICALLY AS RAIN SHIELD CONTINUES TO ADVECT IN FROM
THE SOUTHWEST. VFR CEILINGS RETURN GENERALLY AFTER 21Z...WITH
NORTHWEST FLOW TAKING HOLD AT THE SURFACE BEHIND THE COLD FRONT.
LOW LEVEL MOISTURE DISSIPATES OVERNIGHT.

AFTER 12Z TUESDAY...
IFR POSSIBLE IN RAIN WEDNESDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...26/ARJ
NEAR TERM...26
SHORT TERM...ARJ
LONG TERM...KTB
AVIATION...26