Area Forecast Discussion
Issued by NWS Wakefield, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KAKQ 281405
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
905 AM EST SUN DEC 28 2014

.SYNOPSIS...
COLD FRONT APPROACHES FROM THE WEST TODAY. LOW PRESSURE OVER THE
GULF STATES WILL LIFT ALONG THE FRONT TODAY...REACHING THE LOCAL
AREA THIS AFTERNOON. THE FRONT STALLS OFFSHORE TONIGHT AS ANOTHER
AREA OF LOW PRESSURE LIFTS INTO THE CAROLINAS TONIGHT INTO MONDAY
MORNING. THE FRONT REMAINS JUST OFFSHORE TUESDAY AS HIGH PRESSURE
SLOWLY BUILDS IN FROM THE WEST.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
9AM UPDATE...HAVE LOWERED POPS EVEN FURTHER THROUGH 18Z BASED UPON
LATEST RADAR TRENDS...WHICH SUGGEST NO WIDESPREAD RAINFALL UNTIL
THIS AFTERNOON. SOME ADJUSTMENTS HAVE ALSO BEEN MADE TO HOURLY
TEMPS...AND MAX TEMPS OVER THE WATER.

7 AM UPDATE...QUICK UPDATE TO FORECAST TO TREND POPS DOWNWARD
TODAY. LATEST GUIDANCE COMING IN SLIGHTLY DRIER THAN PREVIOUS
RUNS. LOW LEVEL SWLY FLOW AND WEAK FORCING ALOFT THUS FAR HAS BEEN
SLOW TO SATURATE THE LOWEST LEVELS...SO EXPECT PRECIP TO HOLD OFF
UNTIL MID-LATE MORNING. REGIONAL MOSAIC DEPICTS ECHOES OVER CNTRL
NC...BUT OBS STILL INDICATING CLOUD COVER AOA 12K FT AGL.
HOWEVER...UPSTREAM CLOUDS HAVE BEGUN TO LOWER OVER SC. WILL
CONTINUE TO MONITOR TRENDS AND ADJUST ACCORDINGLY.

PREV DISCUSSION...
PER LATEST WATER VAPOR IMAGERY...RIDGE AXIS HAS PUSHED OFFSHORE
WITH MOISTURE STREAMING NEWD FROM THE SRN PLAINS AND WRN GULF OF
MEX IN DEEP SWLY FLOW. LATEST BLENDED PRECIP WATER DEPICTS BROAD
AREA OF 200 PCT OF NORMAL PRECIP WATER STREAMING ALONG THE
APPALACHIANS INTO SE CANADA. UPSTREAM TROUGH AND ASSOCIATED COLD
FRONT OVER THE CNTRL CONUS WILL CONTINUE TO PROGRESS EWD THIS
MORNING AS AN AREA OF LOW PRESSURE STRENGTHENS OVER THE LOWER MS
VALLEY. ASSOCIATED AREA OF PRECIP HAS SPREAD INTO THE TN VALLEY
THIS MORNING...WITH CONVECTION OBSERVED OVER THE GULF STATES.
SUBSIDENCE STILL WINNING OUT OVER THE LOCAL AREA WITH DEWPOINT
DEPRESSIONS OF 10-15 DEGS. FIRST IN A SERIES OF UPPER WAVES FROM
THE DEAMPLIFYING TROUGH OVER THE CNTRL CONUS LIFTS INTO THE REGION
THIS MORNING. STRONG JET STREAK (180+ KT) DEVELOPS OVER THE GREAT
LAKES/OH VALLEY...WHICH IN TANDEM WITH SHORTWAVE ENERGY WILL
RESULT IN UVM OVER THE LOCAL AREA THIS MORNING. LOW LEVELS REMAIN
DRY THRU EARLY MORNING...BUT UVM AND INCREASING MOISTURE WILL
RESULT IN THE LOW LEVELS SATURATING THIS MORNING. AS THE LOW LIFTS
NEWD ALONG THE SFC FRONT...ISENTROPIC LIFT INCREASES. WITH ALL
THAT SAID...THE RESULT WILL BE LIGHT RAIN SPREADING INTO THE
REGION THIS MORNING AND THIS AFTERNOON. THE EXCEPTION WILL BE IN
THE SE WHERE PRECIP WILL BE MORE SCATTERED IN NATURE. SFC LOW
LIFTS ALONG THE FRONT INTO THE REGION THIS AFTERNOON AS THE FIRST
WAVE OF PRECIP EXITS THE COAST. WILL HOLD ONTO CATEGORICAL POPS
ACROSS THE NE LATE TODAY...BUT THE REST OF THE AREA WILL LIKELY
SEE A LULL. HOWEVER...ABUNDANT LOW LEVEL MOISTURE AND THE UPPER
JET WILL RESULT IN ADDITIONAL DRIZZLE/LIGHT RAIN. RAINFALL TOTALS
TODAY WILL BE RATHER LIGHT...GENERALLY LESS THAN ONE QUARTER OF AN
INCH.

PRECIP AND ABUNDANT CLOUD COVER WILL PREVENT TEMPS FROM REACHING
THEIR FULL POTENTIAL...WARMING INTO THE MID-UPPER 50S (8 TO 12
DEGS OVER MILD MORNING LOWS). WHERE PRECIP IS DELAYED IN THE
SE...TEMPS EXPECTED TO WARM INTO THE LOW 60S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
COLD FRONT CROSSES THE REGION THIS EVENING...BUT STALLS OFF THE
COAST IN DEEP LAYER SWLY FLOW. SRN PORTION OF THE FRONT STALLS
OVER THE SE COASTAL PLAIN. MOISTURE REMAINS IN PLACE AS THE NEXT
SHORTWAVE DEAMPLIFIES AND LIFTS INTO THE REGION. HEIGHT FALLS WILL
PRODUCE ANOTHER WAVE OF LOW PRESSURE ALONG THE FRONT OVER THE
SE...LIFTING ALONG THE FRONT INTO THE CAROLINAS MON MORNING.
INCREASING ISENTROPIC LIFT IN TANDEM WITH THE RIGHT ENTRANCE
REGION OF THE STRONG UPPER JET AND SHORTWAVE ENERGY WILL AGAIN
RESULT IN WIDESPREAD PRECIP. HAVE BUMPED POPS UP TO CATEGORICAL
AFTER MIDNIGHT TONIGHT INTO MONDAY MORNING ACROSS MUCH OF THE
LOCAL AREA AS MODELS HAVE COME INTO GOOD AGREEMENT. FRONT FINALLY
PUSHES OFFSHORE MON MORNING WITH CATEGORICAL POPS CONFINED TO THE
SE MON MORNING. BUFR SOUNDINGS INDICATE LOW LEVELS WILL REMAIN
SATURATED THRU THE DAY MON AS SWLY FLOW ALOFT PREVAILS. WEAK
PERTURBATIONS IN THE FLOW ALOFT WILL RESULT IN ADDITIONAL CHANCES
FOR LIGHT RAIN/DRIZZLE MON AFTERNOON. ABUNDANT CLOUD COVER
PERSISTS. TOTAL QPF THRU MONDAY WILL RANGE FROM NEARLY ONE INCH IN
THE WEST TO HALF AN INCH IN THE EAST.

TEMPS DROP OFF THIS EVENING INTO THE MID-UPPER 40S NE TO LOW 50S
SE...BEFORE LEVELING OFF THRU THE OVERNIGHT. BEST CAA ARRIVES LATE
TONIGHT WITH LOWS EXPECTED IN THE LOW-MID 40S. CAA CONTINUES THRU
THE DAY MON WITH TEMPS ONLY WARMING A FEW DEGS MON. HIGHS
GENERALLY IN THE MID-UPPER 40S.

THE NEXT SHORTWAVE CROSSES THE LOWER MO VALLEY INTO THE OH VALLEY
MON NIGHT-TUES MORNING. FLOW ALOFT BECOMES WLY...USHERING IN DRIER
AIR. HOWEVER...ONSHORE FLOW/SFC RIDGING OVER THE LOCAL AREA KEEPS
LOW LEVEL MOISTURE LOCKED IN PLACE. CLOUDY CONDITIONS WILL
PERSIST. SHORTWAVE AND STRONG WINDS ALOFT WILL RESULT IN UPSLOPE
PRECIP OVER THE CNTRL APPALACHIANS. THE FRONT WILL ALSO REMAIN
STALLED JUST OFFSHORE. WILL FOCUS LOW END CHANCE POPS ACROSS THE
PIEDMONT AND IN THE SE. DETERMINISTIC MODELS AND ENSEMBLE GUIDANCE
PROVIDING A WIDE RANGE OF TEMPS EARLY TUES MORNING...WITH THE NAM
BEING THE COLDEST. HOWEVER...THE NAM REMAINS AN OUTLIER...SO HAVE
TRENDED TOWARD GFS/ECMWF GUIDANCE. THE RESULT IS MOSTLY LIQUID
PRECIP OVER THE NW. WILL NEED TO MONITOR FUTURE TRENDS TO
DETERMINE THERMAL PROFILE. EVEN IF SNOW IS ABLE TO
FALL...ANTICIPATE LITTLE IF ANY ACCUMULATION ATTM. LOWS IN THE
MID-UPPER 30S. TEMPS ONLY REBOUND INTO THE LOW-MID 40S UNDER
ONGOING CAA.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GFS/ECMWF REMAIN IN GOOD AGREEMENT TUESDAY NIGHT THROUGH THE
DAYTIME HOURS ON FRIDAY WITH REGARD TO OVERALL PATTERN. A COLD
ZONAL FLOW WILL PREVAIL ALOFT ACROSS THE REGION
WEDNESDAY/THURSDAY...WITH HIGH PRESSURE BUILDING INTO AND ACROSS
THE AREA. WEATHER IS EXPECTED TO BE DRY WITH TEMPERATURES AT OR
SLIGHTLY BELOW NORMAL FOR LATE DECEMBER. LOW TEMPS TUESDAY NIGHT
AND WEDNESDAY NIGHT AROUND 25-30 DEGREES...A BIT WARMER NEAR THE
COAST. LOWS THURSDAY NIGHT IN THE UPPER 20S NW TO THE LOW-MID
30S SE...WITH MIN TEMPS EXPECTED TO OCCUR BEFORE 06Z...AS CLOUDS
INCREASE OVERNIGHT. HIGH TEMPS TUESDAY THROUGH THURSDAY IN THE
40S...AND IN THE 40S ALL AREAS FRIDAY (EXCEPT SE VA/NE NC WHERE
50S LOOK LIKELY).

GFS/ECMWF CONTINUE TO DIVERGE FROM NEXT FRIDAY NIGHT THROUGH
SATURDAY NIGHT WITH REGARD TO TIMING OF LOW PRESSURE AND ASSOCIATED
COMPLEX FRONTAL SYSTEM. GFS REMAINS 12-18 HOURS FASTER THAN
ECMWF WHICH DEVELOPS A WAVE ALONG THE FRONT SATURDAY
NIGHT...DELAYING THE FRONTAL PASSAGE UNTIL SUNDAY. REGARDLESS...
FRIDAY NIGHT INTO SATURDAY NIGHT NEXT WEEK LOOKS TO BE UNSETTLED
WITH CLOUDS AND SHOWERS. HOWEVER...TEMPERATURES WILL WARM TO
ABOVE NORMAL ON SATURDAY WITH MANY AREAS POTENTIALLY IN THE 60S.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
VFR CONDS PREVAIL AS OF 12Z THIS MORNING...A FEW SPOTTY LIGHT
SHOWERS POSSIBLE LATE THIS MORNING OVER SE VA/NE NC BUT OVERALL
DRY WX SHOULD PERSIST. SW WINDS 10-15 KT THROUGH 18Z OR SO WITH
CIGS MAINLY 5-10 K FT. LATER TODAY...SHOULD SEE RAIN BECOME A BIT
MORE WIDESPREAD ALTHOUGH CIGS ARE STILL EXPECTED TO STAY ABOVE 3 K
FT. WINDS SHIFT TO THE NNW AND THEN THE NNE BETWEEN 00-06Z AND
THIS IS WHEN CIGS/VSBYS ARE EXPECTED TO DETERIORATE AS MUCH COLDER
AIR AND LOW LEVEL MOISTURE ADVECTS INTO THE REGION. WENT WITH IFR
CONDITIONS ALL SITES AT SOME POINT AFTER 06Z/MON. WINDS WILL
BECOME SOMEWHAT GUSTY NEAR THE COAST.

OUTLOOK...STEADY RAIN/NNE WINDS AND IFR CONDITIONS SHOULD CONTINUE
MON. A LULL IN THE PRECIP IS EXPECTED MONDAY AFTN/EVENING. LOW
PRESSURE MOVING ALONG THE FRONT TO THE SOUTH WILL BRING ANOTHER
ROUND OF RAIN AND PSBL IFR CONDS MONDAY NIGHT INTO TUESDAY. VFR
AND DRY WEATHER ARE EXPECTED WEDNESDAY AND THURSDAY.

&&

.MARINE...
SW FLOW AVERAGING 10-15 KT THIS MORNING (EVEN A TAD HIGHER THROUGH
15Z)...WILL TEND TO DIMINISH TO 5-10 KT LATER TODAY AS A COLD
FRONT MOVES CLOSER TO THE AREA AND THE PRESSURE GRADIENT WEAKENS.
SEAS AVG 2-3 FT TODAY...WITH BAY WAVES 1-2 FT.

WHILE THIS FRONT IS NOT PARTICULARLY STRONG...EXPECT ENOUGH OF A NNE
SURGE IN IT`S WAKE LATE TONIGHT/EARLY MON TO RAISE SCA HEADLINES FOR
THE LOWER/MIDDLE BAY FOR WINDS TO 20 KT. GRADIENT WEAKENS BY MON
AFTN SO ENDED THE SCA ATTM FOR NOW. DID NOT RAISE HEADLINES FOR THE
COASTAL WATERS BUT EXPECT SEAS TO BUILD TO AROUND 5 FT FOR WATERS S
OF CAPE CHARLES LIGHT IN N/NE 20 KT WINDS DURING THE DAY MON (3RD
PERIOD). NEXT SHIFT MAY NEED TO ADD THESE ADDITIONAL HEADLINES.
FOLLOWING CLOSER TO A GFS/ECMWF/CMC BLEND FOR WINDS (NAM AN OUTLIER
AT DEVELOPING A MUCH STRONGER SFC LOW TUE/TUE NIGHT. THIS CONSENSUS
SOLUTION STILL SUPPORTS WINDS TO INCREASE BACK TO 15-25 KT FOR MOST
OF THE REGION LATE MON NIGHT/TUE WITH SEAS BUILDING TO 5-7 FT ACRS
SOUTHERN COASTAL WATERS...AND 3-4 FT IN THE LOWER BAY. SFC HIGH
PRESSURE SLOWLY BUILDS INTO THE AREA BY MIDWEEK...WITH WINDS/SEAS
DIMINISHING TUE NIGHT/WED.

&&

.EQUIPMENT...
KDOX 88D RADAR IS EXPECTED TO BE OUT OF SERVICE THROUGH AT LEAST
WED 12/31. SEE FTMDOX (FREE TEXT MESSAGE) FOR DETAILS.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO NOON EST MONDAY FOR ANZ631-
     632-634.

&&

$$
SYNOPSIS...SAM
NEAR TERM...SAM/WRS
SHORT TERM...SAM
LONG TERM...WRS
AVIATION...LKB
MARINE...LKB
EQUIPMENT...





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.