FXUS61 KAKQ 150244
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
944 PM EST MON DEC 14 2009
.SYNOPSIS...
HIGH PRESSURE MOVES OFF THE COAST TONIGHT. A QUICK MOVING COLD
FRONT CROSSES THE REGION DURING TUESDAY. HIGH PRESSURE AND MUCH
COLDER AIR BUILDS INTO THE AREA WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATED 941 PM...
BIGGEST FCST CONCERN FOR THE OVERNIGHT PERIOD WILL BE WITH
DIAGNOSING THE DENSE FOG THREAT...AS PER PREVIOUS DISCUSSION. MANY
LOCALES OVER SERN VA/NERN NC HAD VSBYS GO DOWN AOB 1/4 MILE A
LITTLE EARLIER THIS EVENING...HOWEVER OF LATE VSBYS HAVE COME UP A
BIT IN LIGHT OF SOME INCREASING HIGH CLOUDS PER IR LOOPS ALONG
WITH A LITTLE MORE STIRRING IN THE BNDRY LAYER (AS SFC WINDS VEER
FROM SE TO MORE S AND SW).
FOR THE OVERNIGHT...CONTINUE TO EXPECT RESIDUAL STRATUS LAYER TO
EXPAND OVER FCST AREA...AT LEAST IN THE SHORT TERM. INCREASING
WRLY FLOW IN THE LOWER LEVELS (WSW OFF THE SFC) WILL PROBABLY TEND
TO SHRINK/FURTHER SHALLOW THE STRATUS...HOWEVER AT THIS POINT FEEL
THE LOW CLOUD COVER WILL BE TOUGH TO DISLODGE ALTOGETHER. THE CURRENT
THINKING IS TO MAINTAIN A CLOUDY OR MSTLY CLOUDY FCST WITH AREAS OF
FOG...AS CONTNIUE TO EXPECT LESS DENSE FOG COVERAGE DURING THE
OVERNIGHT HOURS WHILE THE LOWER AND UPPER CLOUD LAYERS EXPAND.
TEMPS WILL REMAIN FAIRLY STEADY OVERNIGHT...PROBABLY RISE A COUPLE
OF DEGREES LATE WITH A LITTLE MORE BNDRY LAYER MIXING (SW/WSW
FLOW).
PREVIOUS (AFTERNOON) DISCUSSION FOLLOWS BELOW...
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
COLD FRNT WILL CROSS THE AREA DURING TUE...WITH WEAK LO PRES
TRACKING THRU THE SE STATES AND OFF THE CST. MODELS ARE STILL
CONSISTENT IN KEEPING BULK OF DEEPER MOIST ASSOC WITH THE LO PRES
AREA PASSING BY S OF THE FA. SO...HAVE CONFINED SLGT OR SML CHC
FOR SHRAS OVR EXTRM SE VA AND NE NC. LO LVL CAA WILL BE DELAYED ON
TUE...RESULTING IN A MILDER DAY (FOR MID DEC)...WITH HI TEMPS FM
THE UPR 50S TO LWR 60S UNDR PRTLY SNY TO CLDY SKY.
LLVL CAA ARRIVES IN ERNEST TUE NGT THRU WED...WITH A PERIOD OF
GUSTY NNW WNDS (LASTING SVRL HRS LNGR NEAR THE CST THAN INLAND)...
AND A CLR OR MSTLY CLR SKY. MIN TEMPS IN THE UPR 20S TO NEAR 40
TUE NGT...AND HI TEMPS ON WED IN THE LWR TO MID 40S.
THE CNTR OF THE SFC HI BLDS OVR THE REGION THRU THU...MAINTAINING
CHILLY/DRY WX. LOWS WED NGT RANGING THRU THE 20S TO NEAR 30...AND
MAX TEMPS ON THU RANGING THRU THE 40S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRS OVR THE NRN STATES KEEPS DRY AND SEASONABLY COLD CNDTNS
FRI & SAT. HIGHS 45-50. LOWS IN THE 20S TO NR 30.
MODELS CONT TO DISAGREE WITH JUST HOW FAR N MSTR FROM YET ANTHR
SRN STREAM GULF COAST LOW GETS. GFS MORE PROGRESSIVE AND NRN STREAM
DOMINATED WITH FIRST SYSTM SLIDING S OF RGN WITH A SCND LOW DVLPNG
ALONG CAROLINA COAST SATURDAY NITE AND SUN. ECMWF HAS A MUCH MORE
AMPLIFIED SYSTM ALONG THE COAST WITH SCND S/W NRGY TRYING TO PHASE
WITH FIRST ONE. HPC GUID FOLLOWS MORE OF A GFS TREND WITH CHC POPS
SAT NITE/SUN ACROSS SE VA/NE NC. THIS SCENARIO WUD KEEP TMPS WRM
ENUF TO SPRT A LIQUID EVENT ALONG THE COAST. HIGHS THIS WKEND M40S
TO L50S SE. LOWS IN THE 30S TO L40S SE. WILL NOT STRAY FROM THESE
TRENDS UNTIL CONFIDENCE GETS A BIT HIGHER.
COLDER AND DRYER AIR MOVES IN BEHIND THIS SYSTM MON. HIGHS U30-M40S.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
MOIST LAYER BELOW 1K FT IS RESULTING IN STRATUS ACROSS SE VA AND NE
NC. THE MAIN PRODUCER OF LIFR VSBYS WILL LIKELY BE STRATUS LOWERING
TO NEAR THE GROUND AND CEILINGS ARE LOWERING QUICKLY IN VICINITY OF
PHF AND ORF. ECG WAS ALREADY VLIFR AT TAF ISSUANCE. RIC AND SBY WILL
LIKELY SEE SIMILAR CONDS LATER. ONE THING TO CONSIDER WILL BE STRONG
BOUNDARY LAYER WINDS IN THE ORDER OF 40 KTS AT 950MB. THIS WILL
LIMIT THE DEPTH OF THE STRATUS AND HELP DISSIPATE THE FOG IN THE
MRNG A LITTLE QUICKER.
A COLD FRONT WILL CROSS THE AREA TUE WITH ONLY A SLGT CHC OF PCPN
OVER SE AREAS (NOT MENTIONED IN THE TAFS). VFR CONDS WILL TAKE OVER
BY LATE TUE MRNG. WINDS WILL TURN TO W/NW DURING THE DAY TUE.
WINDS WILL INCR OUT OF THE N/NW TUE NIGHT AND WED. VFR CONDS SHOULD
CONTINUE INTO FRI. NE WINDS TO THE N OF A WEAK LOW PRESSURE SYSTEM
MAY BRING LOWER CEILINGS TO THE AREA BY LATE SAT.
&&
.MARINE...
NO FLAGS IN SHORT TERM AS RETURN S-SW FLOW SETS UP AS HIGH PRS MOVES
OFFSHORE. STRNG CAA PROGGED BEHIND CDFRNT TUE NIGHT THRU WED AFTRN.
WILL HOIST SCA'S FOR THIS TIME FRAME AS NW WNDS BECOME GUSTY UP TO
30 KTS. WNDS DMNSH WED NITE WITH A GNRL N-NW FLOW AOB SCA LVLS THU
THRU FRI. HIGH PRS BUILDS IN FROM THE N SAT. WNDS TURN MORE N-NE AND
BEGIN TO INCRS AS P-GRDNT INCRS BTWN THIS HIGH AND DVLPNG LOW OFF
THE CAROLINA COAST BY SAT NITE.
&&
.HYDROLOGY...
RIVER FLOOD WARNINGS (FOR MINOR FLOODING) ARE NOW IN EFFECT FOR
THE APPOMATTOX RIVER BASIN (FARMVILLE...MATTOAX...AND MATOACA)...
AS WELL AS FRANKLIN...SEBRELL...AND LAWRENCEVILLE IN THE CHOWAN
BASIN. PLEASE REFER TO THE LATEST FLSAKQ FOR FURTHER DETAILS.
NEW INFORMATION: RICHMOND (WESTHAM) CAME CLOSE TO MINOR FLOODING
EARLIER THIS EVENING...PEAKING AT 11.87 FT (FLOOD STAGE IS 12).
RECENT GAGE DATA SHOWS A DECLINING TREND...THUS NO FLOODING IS
EXPECTED.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM TUESDAY TO 6 PM EST WEDNESDAY
FOR ANZ630>633-650-652-654-656-658.
&&
$$
SYNOPSIS...BKH
NEAR TERM...BKH
SHORT TERM...TMG
LONG TERM...MPR
AVIATION...LSA
MARINE...MPR
HYDROLOGY...AKQ
