000
FXUS61 KRNK 061104
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
604 AM EST TUE JAN 6 2009
.SYNOPSIS...
HIGH PRESSURE IS GOING TO SLIDE SOUTH INTO THE BLUE RIDGE
TODAY...WHILE A FRONT REMAINS NEARLY STATIONARY ACROSS NORTH
CAROLINA. LOW PRESSURE OVER THE GULF COAST STATES WILL TRACK NORTH
INTO THE EASTERN KENTUCKY TODAY...THEN LIFT NORTH INTO THE EASTERN
OHIO VALLEY TONIGHT...BRING THE WARM FRONT THROUGH THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
RAINFALL IS WIDESPREAD ACROSS THE FORECAST AREA...AND EXPECT
CATEGORICAL POPS THROUGH THE PERIOD. MESONET OBS DEPICTING
FREEZING TEMPS STILL NORTH OF THE AREA ALONG THE BLUE RIDGE EAST
OF STAUNTON. THE FREEZING RAIN POTENTIAL IS LOOKING LESS
LIKELY...AS TEMPS HAVE STAYED WARMER THAN MODELS HAVE DEPICTED.
HIGH PRESSURE IS OVER THE DELMARVA AREA...AND THE COOLER TEMPS ARE
SLOWLY SINKING SWWD. WILL KEEP THE ADVISORY GOING AS IS...AS SOME
OF THE BLUE RIDGE...AND HIGHLANDS WEST INTO NE GREENBRIER COULD
SEE A PERIOD OF ICE MAINLY LATE THIS MORNING THROUGH THE
AFTERNOON. HAVE CUT BACK ON ICE AMOUNTS TO AROUND OR LESS THAN A
TENTH OF AN INCH. HEAVIER RAINFALL RATES EXPECTED SHOULD KEEP THE
GROUND WARM DUE TO LATENT HEAT RELEASE...AND ANY ICE ACCUMULATION
WOULD MAINLY BE CONFINED TO METAL OBJECTS OR TREE BRANCHES.
ISOLATED BRIDGES NORTH OF HSP OR ALONG THE BLUE RIDGE PARKWAY IN
AMHERST MAY GET ICED OVER. FOR TEMPS...BASICALLY RAN CLOSE TO THE
LAMP DATA...WITH ADJUSTMENTS DOWN IN THE NORTH TO ACCOUNT FOR
COLDER SHALLOW AIR SEEPING IN.
THE REST OF THE AREA WILL SEE RAIN ALL DAY. GOOD LIFT ALONG THE
WARM FRONT WITH INCREASING SW FLOW WILL BRING ELEVATED CONVECTION
THE NC PIEDMONT INTO SOUTHSIDE VA THIS AFTERNOON/EARLY EVENING.
THE GFS IS BULLISH WITH 8H WINDS AROUND 70+ KNOTS TONIGHT WHILE
THE NAM IS MORE AROUND 50-60 KNOTS...AND IS HOLDING ONTO THE WEDGE
LONGER. EXPECT THE WEDGE TO ERODE ONCE THE LOW MOVES NORTH INTO
THE MID ATLANTIC...BUT THAT DOESNT LOOK TO OCCUR UNTIL WED.
NONETHELESS WARMER AIR AND HEAVIER RAINFALL WILL SCOUR OUT ANY
FREEZING TEMPS IN THE NORTH...SO LOOK FOR SLOWLY RISING TEMPS
TONIGHT.
FLOOD WATCH THROUGH WEDNESDAY AS TWO SLUGS OF MOISTURE TO BRING
2-4 INCHES TODAY-WEDNESDAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
SECONDARY WAVE WILL PASS TO THE NW EARLY WED WITH THE TRAILING COLD
FRONT WORKING THRU THE REGION FROM WEST TO EAST BY LATE IN THE DAY.
EXPECT BAND OF HEAVIEST PREFRONTAL SHRA TO BE OVER THE WESTERN ZONES
WED MORNING...THEN TRANSLATING EAST THRU THE WEDGE BY EARLY
AFTERNOON. GOOD LIFT IN ASSOCIATION WITH THE LEADING EDGE OF THE
UPPER TROF SPELLS POSSIBLY ANOTHER BRIEF ROUND OF HEAVY RAIN ESPCLY
WEST WHICH ON TOP OF EARLIER RAIN COULD CAUSE FLOODING PROBLEMS.
PRECIP BECOMES LIGHTER AND MORE SCATTERED FROM WEST TO EAST BY LATER
WED AFTERNOON...BEFORE MUCH COLDER AIR ARRIVES WED EVENING. THUS
UPPED POPS SOME DURING WED...THEN CUT BACK LATE WED INTO WED NIGHT
ESPCLY EAST AS DOWNSLOPE KICKS IN. WITH SURFACE TEMPS LOOKING A BIT
WARMER UNTIL THE UPPER COLD POOL ROTATES EAST WED EVENING...SLOWED
DOWN CHANGE TO SNOW WESTERN SLOPES A BIT UNTIL MAINLY WED
NIGHT...THEN BOOSTED COVERAGE SOME THRU MIDDAY THU WHEN STRONGER
WAVE KICKS THRU UNDER THE 5H UPPER SYSTEM. MORE WESTERLY FLOW AND
CHANGEABLE DEPTHS TO LOW LEVEL MOISTURE LIKELY TO LIMIT TOTALS BUT
THINKING A 1-3 INCH TYPE EVENT WESTERN SLOPES WITH PERHAPS MORE
WESTERN GREENBRIER SO WILL KEEP HWO MENTION. OTRW MAINLY DRY/PC
EAST WED NIGHT-THU NIGHT WITH ONLY SCTD FLURRIES ELSW OVER THE
WEST EAST OF THE PRIME UPSLOPE LOCATIONS. BEST WIND GRADIENT
APPEARS AS THE COLD ADVECTION INCREASES BEHIND THE FRONT WED NIGHT
INTO EARLY THU WITH 85H JET OF 35-40 KTS. HOWEVER BETTER PRES RISES
LIKELY TO PASS TO THE NORTH WHICH SHOULD LIMIT SPEEDS...WITH BEST
WIND ADVISORY POTENTIAL ACROSS THE NORTH WHERE THE JET WILL BE
STRONGEST.
TEMPS WILL BE TRICKY ON WED AS MAY SEE READINGS JUMP A BIT AS THE
FRONT SCOURS THE WEDGE OUT BEFORE READINGS FALL OVER THE WEST IN THE
AFTERNOON. OTRW RUNNING WITH A BLEND OF ENSEMBLE 40S AND LOW/MID 50S
FOR HIGHS. COLD ADVECTION BEST IN THE WEST WED NIGHT AND THEN NW
SECTIONS THU WHERE CLOUDS/-SHSN SHOULD KEEP MOST BELOW FREEZING.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ON FRIDAY...HIGH PRESSURE WILL MOVE FAIRLY QUICKLY ACROSS THE
REGION. THE RESULT WILL BE A PRECIPITATION FREE DAY. BY FRIDAY
EVENING...THE HIGH WILL BE EAST OF THE REGION...AND WE WILL START TO
GET ON RETURN FLOW SOUTHERLY TRAJECTORY SIDE OF THE FEATURE. HELPING
TO FUEL A RETURN TO SOUTHERLY AND MOIST FLOW WILL BE AN AREA OF
LOW PRESSURE ADVANCING TOWARDS THE REGION FROM THE MID MISSISSIPPI
RIVER VALLEY. TOWARDS DAYBREAK SATURDAY...ISENTROPIC FLOW ASSOCIATED
WITH THE SYSTEMS ASSOCIATED WARM FRONT WILL BE MOVING INTO WESTERN
PARTS OF THE REGION. COVERAGE WILL CONTINUE TO INCREASE DURING THE
MORNING ON SATURDAY AS THE SURFACE LOW PASSES TO OUR NORTH AND ITS
ASSOCIATED COLD FRONT MOVES THROUGH THE AREA. WITH COLD AIR AT THE
SURFACE IN PLACE...AND THE WARM FRONT ACROSS THE AREA FRIDAY
NIGHT...WE WILL NEED TO WATCH FOR THE POTENTIAL OF A WINTRY MIX IN
THE WEST LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING. WITH
SATURDAY AFTERNOON TEMPERATURES EXPECTED TO BE IN THE UPPER 30S TO
NEAR 50 DEGREES...MOST AREAS WILL TRANSITION TO RAIN SHOWERS.
SATURDAY NIGHT INTO SUNDAY A REINFORCING SHOT OF UPSTREAM ENERGY
HEADS INTO THE REGION ALONG WITH REINFORCING COLDER AIR. THE RESULT
WILL BE A CONTINUATION OF SCATTERED SNOW/RAIN SHOWERS ACROSS THE
AREA...WITH DECREASING COVERAGE DURING THE DAY SUNDAY...WITH THE SE
WV MOUNTAINS KEEPING THE SNOW SHOWERS THE LONGEST.
THE COLD AIR AT THE SURFACE WILL STAY IN PLACE SUNDAY NIGHT INTO
MONDAY. WE WILL START TO SEE SOME WARM AIR ADVECTION ALOFT BY THE
AFTERNOON MONDAY AS SURFACE LOW PRESSURE MOVES INTO THE LOWER OHIO
VALLEY AND WINDS AHEAD OF IT BECOME MORE SOUTHWEST AND START TO TAP
INTO SOME GULF COAST MOISTURE TO STREAM OUR WAY. LIGHT RAIN OR LIGHT
SNOW WILL BE POSSIBLE IN THE WEST MONDAY AFTERNOON THANKS TO THIS
MOISTURE ADVECTION.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
THE APPROACH OF THE NEXT SIGNIFICANT WEATHER SYSTEM TODAY AND
TONIGHT WILL RESULT IN ANOTHER PROLONGED PERIOD OF IFR TO LIFR
CONDITIONS...ALONG WITH WIDESPREAD CONTINUOUS RAIN...WITH FREEZING
RAIN POSSIBLE NORTHEAST OF KLWB AND NORTHWEST OF KLYH IN THE BLUE
RIDGE/HIGHLANDS. TAF SITES ARE EXPECTED TO SEE ONLY LIQUID RAIN
THRU THE EVENT.
WILL KEEP THE TAF SITES DOWN...ALTHOUGH CANNOT RULE OUT SOME
IMPROVEMENTS IN THE LOWER CIGS...ESPECIALLY AT BLF THRU LATE IN
THE DAY TODAY.
ARRIVAL OF A STRONG COLD FRONT WILL ALLOW FOR CONDITIONS TO
IMPROVE BACK TO VFR EAST OF THE BLUE RIDGE ON WEDNESDAY AS STRONG
DOWNSLOPE WINDS TAKE OVER. FURTHER WEST...UPSLOPE CLOUDS AND POST
FRONTAL SNOW SHOWERS SHOULD ASSURE THAT MVFR TO IFR WEATHER
CONTINUE ACROSS SOUTHEASTERN WEST VIRGINIA TERMINAL FORECAST
POINTS WELL INTO THURSDAY NIGHT. WEAK HIGH PRESSURE BUILDS IN
FRIDAY BRINGING A RETURN TO VFR FOLLOWED BY ANOTHER COLD FRONT SAT
WHICH COULD BRING BRIEF MVFR CONDITIONS IN -RA/-SN SHOWERS BY SAT
AFTERNOON.
&&
.HYDROLOGY...
FLOOD WATCH FOR THE SOUTHWEST MOUNTAINS...AND THE NC/VA FOOTHILLS
EAST ALONG THE DAN RIVER BASIN THROUGH WEDNESDAY. LOOKING AT 2 TO
4 INCHES POSSIBLE...WITH THE MOUNTAINS GETTING THE BEST SLUG OF
MOISTURE THROUGH TONIGHT...AND OUT EAST TONIGHT INTO WEDNESDAY
MORNING. MAIN CONCERN WILL BE FOR SMALL STREAMS IN THE MOUNTAINS
AND ADJACENT FOOTHILLS FLOODING DURING THE RAIN EVENT...FOLLOWED
BY MAIN STEM FLOODING ALONG THE DAN RIVER AT THE END OF THE RAIN EVENT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FREEZING RAIN ADVISORY UNTIL 9 PM EST THIS EVENING FOR VAZ019-
020-024-035.
FLOOD WATCH THROUGH WEDNESDAY MORNING FOR VAZ007-009-010-012-
015>017.
FLOOD WATCH THROUGH WEDNESDAY AFTERNOON FOR VAZ032-033-043-044-
058.
NC...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NCZ001-002-018.
FLOOD WATCH THROUGH WEDNESDAY AFTERNOON FOR NCZ003-019.
WV...FREEZING RAIN ADVISORY UNTIL 9 PM EST THIS EVENING FOR WVZ045.
FLOOD WATCH THROUGH WEDNESDAY MORNING FOR WVZ042.
&&
$$
SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...JH/KM
LONG TERM...DS
AVIATION...JH/JS/WP
HYDROLOGY...
