FXUS61 KRNK 261132
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
632 AM EST SAT DEC 26 2009
.SYNOPSIS...
LOW PRESSURE WAS OFF THE NORTH CAROLINA COAST EARLY THIS MORNING.
THE STRONG LOW IN THE MIDWEST WAS CENTERED OVER SOUTHERN IOWA.
THE COASTAL LOW WILL MOVE NORTH TOWARD NEW JERSEY TODAY WHILE THE
MID WEST LOW TRACKS TOWARD LAKE MICHIGAN. COLDER HIGH PRESSURE
WILL SLOWLY BUILD INTO THE MID ATLANTIC SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
FOG WAS WIDESPREAD ACROSS THE FORECAST AREA EARLY THIS MORNING.
VISIBILITIES STILL VARIED FROM AROUND 4 MILES TO ONE QUARTER MILE
SO NO DENSE FOG ADVISORY NEEDED AT THIS TIME.
LIGHT PRECIPITATION HAS NEARLY ENDED OVER THE FORECAST AREA. HAVE
CUT BACK THE REMAINING PROBABILITY OF PRECIPITATION FOR THIS
MORNING.
MODELS ARE ERODING THE MOISTURE IN THE ATMOSPHERE FROM THE TOP
DOWN AND CLEARING THE CLOUDS FROM SOUTHWEST TO NORTHEAST. ONLY
MINOR ADJUSTMENT TO CLOUD COVER FOR TODAY. TOOK A BLEND OF MAV/MET
GUIDANCE FOR HIGHS TODAY AND LOWS TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
COLD FRONT WILL CONTINUE PUSHING EAST OVER THE ATLANTIC AS SURFACE
RIDGING NOSES IN FROM THE SOUTHWEST INTO OUR REGION. COLDER DRIER
AIR WILL FILTER FROM THE WEST ACROSS THE REGION WITH 850H
TEMPERATURES BELOW 0 DEGREES C THROUGH MONDAY NIGHT. THE COLDEST AIR
PUNCHES IN WITH -12 DEGREES C AT 850H IN SOUTHEASTERN WEST VIRGINIA
SUNDAY NIGHT.
HIGH TEMPERATURES SUNDAY WILL RANGE FROM THE MID 30S WEST OF THE
BLUE RIDGE MOUNTAINS TO NEAR 50 DEGREES IN THE PIEDMONT. WITH COLD
AIR ADVECTION IN COMBINATION WITH THE CLOUDS THINNING...LOW
TEMPERATURES WILL DROP INTO THE UPPER TEENS TO LOWER 20S IN THE
MOUNTAINS WITH MID 20S EAST SUNDAY NIGHT.
A DISTURBANCE WILL APPROACH THE AREA SUNDAY NIGHT AND PIVOT THROUGH
ON MONDAY. RAISED POPS IN THE WEST LATE MONDAY AND MONDAY NIGHT
BEHIND WAVE AND WITH VEERING OF THE WIND TO FAVORABLE TRAJECTORY.
ALSO 850H WINDS INCREASE TO 40 TO 45 KNOTS MONDAY IN WHICH THE
RIDGETOPS COULD GUST TO 20 TO 25 MPH MONDAY MORNING AND LAST THROUGH
THE DAY. HIGH PRESSURE WILL SLIDE EAST ACROSS THE REGION ON TUESDAY.
PLAYED TEMPERATURES ON TUESDAY CLOSE TO MOSGUIDE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
MID-WEEK PERIOD LOOKS TRANQUIL WITH SURFACE HIGH PRESSURE CENTERED
ACROSS THE MID-MISSISSIPPI VALLEY EARLY TUESDAY SLIDING EAST TO THE
MID-ATLANTIC BY WEDNESDAY. CORE OF THE COLDEST AIR REMAINS WELL TO
THE NORTH ACROSS NORTHERN NEW ENGLAND BUT WITH CLEAR SKIES AND H85
TEMPS -2 TO -6C SHOULD SEE SEASONABLY CHILLY TEMPS TUE AND WED
MORNINGS...GENERALLY UPPER TEENS WEST TO MID-20S EAST. HIGHS ALSO
NEAR TO SLIGHTLY BLO LATE DEC NORMALS RANGING FROM LOW 30S NW TO
MID-40S SE.
BOTH GFS/ECMWF TRY TO DEVELOP LOW PRESSURE ALONG THE GULF COAST
BY EARLY THU AS HIGH PRESSURE DEPARTS THE EAST COAST AND A SHORT-
WAVE ROUNDS THE BASE OF THE LONG-WAVE TROUGH CENTERED SOMEWHERE IN
THE CENTRAL CONUS. THE LATEST RUNS...12Z GFS AND 00Z EC...BOTH
PRODUCE AN INVERTED TROUGH ALONG THE SOUTHEAST COAST BY LATER THU
AND THEN WEAK LOW PRESSURE OFF THE CAROLINA COAST. WEAK LOW
PRESSURE ALONG THE COAST IS ALSO SHOWN BY NEARLY ALL THE GFS
ENSEMBLES WITH THE BULK OF THE PRECIPITATION SOUTHEAST OF THE
FORECAST AREA. HOWEVER THE GENERAL PATTERN REMAINS SOMEWHAT
FAVORABLE FOR MORE SIGNIFICANT COASTAL DEVELOPMENT LATE IN THE
WEEK AND RUN TO RUN MODEL FLUCTUATIONS ARE TO BE EXPECTED IN
FUTURE. FOR NOW HAVE SIMPLY MAINTAINED SLIGHT CHANCE OR CHANCE
POPS FROM EARLY THURSDAY THROUGH THE END OF THIS FORECAST CYCLE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
CONDITIONS MAY FLUCTUATE BETWEEN VLIRF AND MVFR CEILINGS AND
VISIBILITIES THIS MORNING. THE AIR MASS WILL CONTINUE TO DRY OUT
TODAY. AT 14-16Z...CEILINGS AND VISIBILITIES WILL IMPROVE TO VFR
AND REMAIN THAT WAY FOR THE REST OF THE DAY.
ON SUNDAY NIGHT THROUGH MONDAY NIGHT AN UPPER TROF WILL BRING
COLDER AIR BACK INTO THE REGION WITH UPSLOPE LOW LEVEL WINDS IN
THE MOUNTAINS. SNOW SHOWERS ARE EXPECTED IN BLF AND LWB WHICH WILL
RESULT IN MVFR TO OCCASIONALLY IFR CEILINGS AND VISIBILITIES. AT
THIS TIME SNOWFALL AMOUNTS ARE EXPECTED TO REMAIN LIGHT.
EAST OF THE BLUE RIDGE WILL BE VFR INTO WEDNESDAY.
&&
.HYDROLOGY...
STILL GETTING SOME RISES ALONG THE ROANOKE RIVER UPSTREAM OF
WALNUT STREET. HOWEVER...ONLY EXPECTING THE ROANOKE RIVER AT
WALNUT ST TO GET JUST ABOVE THE ACTION STAGE OF 6 FEET BY
DAWN...AS MAIN PRECIP FELL DOWNSTREAM AND SOUTH OF THE AREA.
THE MAIN CHANGE WAS TO INCREASE THE RISE AT SOUTH BOSTON AND
PACES. PACES LOOKS TO REACH CLOSE TO FLOOD STAGE SATURDAY
AFTN...WHILE SOUTH BOSTON FLOODS BUT REMAINS BELOW THE MODERATE
FLOOD CATEGORY OF 25 FEET.
THE JAMES RIVER WILL ALSO HAVE WITHIN BANK RISES. THIS WILL BRING
HOLCOMB ROCK CLOSE TO CAUTION STAGE AND BREMO BLUFF JUST BELOW
FLOOD STAGE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KK
LONG TERM...PC
AVIATION...AMS/JJ/WP
HYDROLOGY...AMS
