FXUS61 KRLX 301816
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
104 PM EST MON NOV 30 2009
.SYNOPSIS...
PRECIPITATION AND FRONT MOVE EAST. HIGH PRESSURE RETURNS LATER
TONIGHT AND TUESDAY. LOW PRESSURE PASSES THURSDAY MORNING. COLDER
THURSDAY NIGHT AND FRIDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
SURFACE PRECIPITATION AND FRONT MOVING EAST WITH CONSISTENCY IN THE
MODELS. UPPER TROUGH WILL MOVE ACROSS THE FORECAST AREA BY AROUND
06Z. POSITION OF HIGH BUILDING INTO THE REGION AND MORE WESTERLY
ORIENTATION OF UPPER FLOW WILL MEAN CLEARING RATHER THEN THE NORMAL
WINTER NORTHWEST FLOW CLOUDINESS. AS COLD AIR COMES IN THE RAIN WILL
BRIEFLY SWITCH TO SNOW SHOWERS IN THE MOUNTAINS BEFORE SWITCHING
OVER BUT ANY ACCUMULATIONS WILL BE LIGHT IN THE HIGHER ELEVATIONS.
HIGH WILL MEAN CLEAR SKIES FOR TUESDAY.
&&
.SHORT TERM /TUESDAY NIGHT 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 MONDAY/...
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 /18Z MONDAY THROUGH SATURDAY/...
MVFR CONDITIONS WITH POST FRONTAL MOISTURE INTO THIS EVENING. LOCAL
IFR IN SHOWERS. AFTER UPPER TROUGH PASSES EAST OF FORECAST AREA
DURING THE NIGHT AND HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST...CONDITIONS WILL IMPROVE TO VFR REMAINING THAT WAY
TUESDAY.
AFTER 18Z TUESDAY...
IFR POSSIBLE IN RAIN WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...AAR
NEAR TERM...AAR
SHORT TERM...ARJ
LONG TERM...KTB
AVIATION...AAR
