008 
FXUS61 KRNK 211944
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
244 PM EST SAT NOV 21 2009

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ACROSS THE AREA TONIGHT. LOW PRESSURE
DEVELOPING ACROSS THE GULF COAST STATES WILL IMPACT OUR WEATHER
SUNDAY WHILE HIGH PRESSURE WEDGES DOWN FROM THE NORTHEAST.

&&

.NEAR TERM /THROUGH SUNDAY/...
SFC HIGH PRESSURE OVER OUR REGION THIS AFTERNOON WILL SHIFT EAST 
TONIGHT INTO SUNDAY. A LOW PRESSURE CENTER WILL MOVE EAST ALONG THE 
GULF COAST...THEN NORTH ALONG THE CAROLINA COAST SUNDAY THROUGH 
MONDAY. MODELS CONTINUED THE TREND OF SLOWING THE ONSET OF PCPN 
ASSOCIATED WITH DEVELOPING WEDGE AND CYCLOGENESIS OVER THE NORTHERN 
GULF. LEANED POPS TOWARDS A GFS/SREF BLEND.

USED GEM/GFS FOR CLOUD COVER TONIGHT AND SUNDAY. SATELLITE LOOP 
SHOWED HIGH CLOUDS THINNING THIS AFTERNOON ACROSS OUR AREA. 
HOWEVER...CLOUD COVER WILL INCREASE TONIGHT ESPECIALLY ACROSS THE 
SOUTH LATE.  LIGHT FLOW WILL BECOME EAST TO SOUTHEAST TONIGHT. 
PLAYED LOWS TONIGHT CLOSE TO MOS...DROPPED A COUPLE DEGREES FROM 
PREVIOUS FORECAST DUE TO SLOWER ARRIVAL OF CLOUDS. HIGH TEMPERATURES 
ARE TRICKY FOR SUNDAY WITH DELAYED ONSET OF PCPN AND THICKER CLOUD 
COVER IN COMPARISON TO SATURDAY. WENT WITH ADJMAVBC FOR HIGH 
TEMPERATURES ON SUNDAY.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
THE TREND OF THE GUIDANCE TO SLOW THE PRECIPITATION ASSOCIATED WITH 
THE COASTAL LOW WILL CONTINUE INTO SUNDAY NIGHT. HAVE MADE 
ADJUSTMENTS TO THE POPS THAT REFLECT A SLOWER TIMING OF THE HIGHER 
POPS INTO THE AREA...HOWEVER HAVE MAINTAINED ROUGHLY THE SAME 
ORIENTATION OF THOSE POPS WITH THE HIGHEST PERCENTAGE ACROSS THE 
SOUTHEAST PART OF THE FORECAST AREA. HAVE CONTINUED THE TREND OF A 
SLOWER EXITING SYSTEM MONDAY INTO EARLY TUESDAY. AS SUCH...HAVE 
INCREASED POPS ON MONDAY INTO MONDAY NIGHT AS COMPARED TO EARLIER 
NUMBERS.

A STRONG...COOL...RAIN FED WEDGE WILL DEVELOP BY MONDAY...AND LAST 
THROUGH AT LEAST TUESDAY. AS SUCH...HAVE GONE WITH FORECAST HIGH 
TEMPERATURES BOTH MONDAY AND TUESDAY LOWER THAN GUIDANCE. BY LATE 
TUESDAY...BUT MORE ESPECIALLY TUESDAY NIGHT...WE WILL SEE A 
TRANSITION TO ISOLATED TO SCATTERED CONVECTIVE PRECIPITATION IN 
ADVANCE OF AN APPROACHING COLD FRONT. WILL HAVE ISOLATED SHOWERS IN 
THE WEST TUESDAY AFTERNOON...BUT INCREASING COVERAGE OF SHOWERS FROM 
WEST TO EAST ON TUESDAY NIGHT...BUT NOTHING HIGHER THAN CHANCE POPS 
AT THIS TIME.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
ECMWF HAS A SURFACE AND UPPER LEVEL LOW OVER THE MIDWEST
APPROACHING THE REGION WEDNESDAY NIGHT INTO THURSDAY MORNING. THE
LOW PUSHES NORTHEAST OVER THE GREAT LAKES WITH MOST OF THE ENERGY
FOLLOWING AND SLIDING NORTH OF THE FORECAST AREA. HAVE CHANCE POPS
IN THE NORTHERN AND CENTRAL PORTIONS OF THE COUNTY WARNING AREA
AND TAPERING OFF FROM THE SOUTHEAST TO NORTHWEST THROUGH FRIDAY.
AGAIN WITH TEMPERATURES AND 1000-850MB...850-700MB THICKNESSES
LOWERING TO NEAR FREEZING...SOME LIGHT SNOW CAN BE MIXED IN WITH
THE RAIN ESPECIALLY IN THE HIGHER ELEVATIONS WEST OF THE BLUE
RIDGE THURSDAY NIGHT. 

MAX TEMPERATURES WILL START COOLING DOWN INTO THE LOW TO MID 40S
IN THE WEST TO LOW 50S IN THE PIEDMONT AREAS OF VA/NC.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. EXPECT 
VFR CONDITIONS THROUGH THE PERIOD WITH CIRRUS/CS CI GS.

LOW PRESSURE WILL SLIDE NORTHEAST FROM THE GULF COAST STATES INTO THE
SOUTHEAST COASTAL AREA BY TUESDAY. LOOK FOR LOWERING CI GS DURING
THE DAY SUNDAY WITH RAINFALL EXPECTED AT THE TAF SITES BY LATE 
SUNDAY. MODELS SEEM TO BE SLOWING THE RAIN START TIMES DOWN...SO
WITH THAT IN MIND WE MAY NOT SEE SUB VFR CONDITIONS UNTIL SUNDAY
NIGHT INTO MONDAY.

TUESDAY WILL FEATURE IMPROVING CONDITIONS AS THE AFC LOW TRACKS
NORTHEAST UP THE EASTERN SEABOARD WITH HIGH PRESSURE BUILDING OVER
THE MID ATLANTIC FOR MID WEEK.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...WP
NEAR TERM...KK
SHORT TERM...DS
LONG TERM...REB
AVIATION...KK/WP