Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 301045
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
645 AM EDT TUE JUN 30 2015

.SYNOPSIS...
LOW PRESSURE WILL SLIDE NORTHEAST ACROSS THE EASTERN GREAT LAKES
TODAY...WITH THE ASSOCIATED COLD FRONT APPROACHING THE AREA FROM
THE NORTHWEST LATE THIS AFTERNOON INTO TONIGHT. THE FRONT WILL
STALL ACROSS THE REGION WEDNESDAY THROUGH SATURDAY...WITH LOW
PRESSURE TRACKING ALONG THE FRONT LATER THURSDAY AFTERNOON INTO
THURSDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE CURRENT UPPER AIR ANALYSIS SHOWS A TROUGH OVER THE GREAT LAKES
REGION...WITH A RIDGE CENTERED OVER THE SUBTROPICAL WRN ATLANTIC.
AT THE SURFACE...A BROAD AREA OF LOW PRESSURE IS SITUATED OVER THE
GREAT LAKES...WITH A COLD FRONT TRAILING BACK THROUGH THE OHIO
VALLEY. THE PRIMARY TROUGH AXIS WILL LIFT ACROSS THE ERN GREAT
LAKES TODAY...WITH A SHORTWAVE TROUGH APPROACHING FROM THE W BY
LATER THIS AFTERNOON. MEANWHILE...THE SURFACE LOW WILL LIFT
THROUGH THE ERN LAKES AS WELL...WITH THE COLD FRONT APPROACHING
FROM THE NW. A PRE-FRONTAL TROUGH DEVELOPS OVER THE REGION TODAY
WITH STRONG DIABATIC HEATING...AND THIS WILL BECOME THE FOCAL
POINT FOR ISO-SCT CONVECTION LATER TODAY INTO THIS EVENING.
EFFECTIVE SHEAR VALUES ARE PROGGED TO REACH 30-40KT BY LATE THIS
AFTERNOON INTO THIS EVENING COINCIDING WITH THE APPROACH OF THE
SHORTWAVE TROUGH. INSTABILITY IS MORE MARGINAL (MLCAPE OF
1000-1500 J/KG) WHEN COMPARED TO THE EVENTS OF JUN 20/25. OVERALL
STORM STRUCTURE SHOULD BE LESS ORGANIZED THAN THOSE EVENTS...BUT A
THREAT OF DAMAGING WIND GUSTS STILL EXISTS BASED ON THE STRENGTH
OF THE SHEAR IN A REGION OF STEEP LOW-LEVEL LAPSE RATES AND A
WELL-MIXED BL.

THE DAY SHOULD BEGIN SUNNY ACROSS THE REGION...BEFORE BECOMING
PARTLY TO MOSTLY CLOUDY LATE THIS AFTERNOON INTO THE EVENING.
HIGHS ARE EXPECTED TO REACH THE UPPER 80S TO LOW 90S. POPS THEN
TAPER OFF AFTER MIDNIGHT WITH PARTIAL CLEAR LATE (ESPECIALLY W).
LOWS TONIGHT ARE FORECAST TO RANGE FROM THE UPPER 60S TO MID 70S.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
THE FRONTAL BOUNDARY SETTLES IMMEDIATELY N OF THE REGION
WEDNESDAY. OVERALL...THERE IS LITTLE FORCING...SO ONLY A ~20% POP
IS FORECAST FOR MOST OF THE AREA...WITH THE EXCEPTION OF ~30%
CLOSER TO THE COAST WHERE LOW-LEVEL MOISTURE WILL BE SOMEWHAT
HIGHER. HIGHS ARE FORECAST TO ONCE AGAIN REACH THE UPPER 80S TO
LOW 90S. PARTLY CLOUDY CONDITIONS ARE EXPECTED WEDNESDAY NIGHT
WITH LOWS IN THE UPPER 60S TO LOW 70S.

THE FRONT SAGS S INTO THE REGION BY THURSDAY.
MEANWHILE...SHORTWAVE ENERGY IS EXPECTED TO TRACK INTO THE CENTRAL
APPALACHIANS BY AFTERNOON. THE 00Z/30 NAM IS THE QUICKEST...WHILE
THE 00/30 GFS/ECMWF/CMC LAG THE ENERGY TO THE W UNTIL AFTERNOON.
AT THIS TIME...THE LATER CONSENSUS SOLUTION HAS BEEN
FAVORED...WITH ONLY 20-30% POPS FORECAST IN THE MORNING...BEFORE
BRINGING 40-50% INTO WRN PORTIONS BY LATER IN THE AFTERNOON...WITH
30-40% FARTHER E. HIGH TEMPERATURES ARE EXPECTED TO RANGE FROM THE
LOW/MID 80S N...TO AROUND 90 SE WITH THE FRONT OVER THE REGION.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNSETTLED CONDITIONS SEEN THRU THE PERIOD AS A FRONTAL BOUNDARY
BECOMES STALLED ACROSS THE REGION WITH SEVERAL S/W`S DROPPING SE
IN THE OVERALL NW FLOW. TIMING OF ANY S/W (OR CONVECTIVE COMPLEX)
RATHER PROBLEMATIC ATTM...SO WILL CARRY THE POPS THROUGH THE 12
HOUR PERIOD VERSUS TRYING TO GO WITH A MORE DIURNAL PATTERN. SOME
CONSENSUS HAS DEVELOPED WITH RESPECT TO A SHORTWAVE TROUGH
TRACKING ACROSS THE REGION THU NIGHT/EARLY FRI. THERE IS A
POTENTIAL FOR HEAVY RAINFALL WITH THIS SYSTEM. A BROAD 50% POP IS
FORECAST AT THIS TIME THU NIGHT/EARLY FRI...BEFORE TAPERING TO
30-40%. THEN BASICALLY 30-40% FOR THE REST OF THE PERIOD EXCEPT
SUNDAY WHERE THE LATEST DATA IS HINTING AT A SOMEWHAT DRIER DAY
(20-30 POP).

TEMPS COOLEST FRI GIVEN WIDESPREAD CLOUD COVERAGE AND PCPN CHCS.
HIGHS IN THE 80S. BOUNDARY LOCATION WILL PLAY A ROLE IN TEMPS
FOR THE REST OF THE PERIOD...BUT MODEL TRENDS ARE FOR THE WARM
FRONT TO EVENTUALLY LIFT NORTH OF THE FA PLACING REGION IN A
MORE HUMID AIRMASS. THUS...HIGHS EACH DAY IN THE M80S-L90S.
LOWS THURSDAY NIGHT U60S-L70S. OTHERWISE...LOWS IN THE 70S.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
VFR THRU THE 12Z TAF PERIOD. SFC HI PRES REMAINS OFFSHORE TDA
WITH SLY FLOW DEVELOPING ACROSS THE MID ATLC. COULD SEE SOME GUSTS
UP TO ~20 KT THIS AFTN WITH MAINLY JUST MID/HI CLOUDS EXPECTED.
SHRAS/TSTMS ARE PSBL THIS AFTN/EVENG ESPECIALLY AT RIC/SBY...BUT
CHANCE IS TOO LO TO INCLUDE IN THE TAFS ATTM.

OUTLOOK...A FRNTAL SYSTM SLOWLY APPROACHES FM THE W DURING THE
REST OF THE WEEK. MAINLY VFR CONDS WILL PREVAIL. THERE WILL BE
CHANCES FOR AFTN/EVENG SHRAS/TSTMS EACH DAY WITH THE HIGHEST
CHANCES ON THU AND FRI WITH THE FRNT IN THE VICINITY.

&&

.MARINE...
HI PRES REMAINS OFFSHORE TDA AS LO PRES TRAVERSES THE GREAT LAKES
REGION. BETWEEN THESE TWO FEATURES...SLY FLOW WILL INCREASE THRU THE
DAY ACROSS THE MID ATLC. MARGINAL SCA REMAINS IN EFFECT FOR THE BAY
STARTING MIDDAY AS THE PRESSURE GRADIENT INCREASES...WITH WINDS
STAYING SUB-SCA OVER THE RIVERS/SOUND/CSTL WTRS. THE SCA ENDS
TNGT...WITH WEAKER SLY/SWLY FLOW (10-15 KT) EXPECTED FOR WED AHEAD
OF AN APPROACHING COLD FRNT. THE FRNT DROPS INTO THE AREA FM THE NW
ON THU...WITH WINDS BCMG LIGHT AND VRB THU AND FRI AS THE FRNT
STALLS OVER THE REGION. WAVES AVG 1-2 FT AND SEAS AVG 2-4 FT THRU
THE WEEK. SEAS MAY COME CLOSE TO 5 FT OVER NRN WTRS AT TIMES.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 AM EDT
     WEDNESDAY FOR ANZ630>632-634.

&&

$$
SYNOPSIS...AJZ/MAM
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...AJZ/MPR
AVIATION...MAS
MARINE...MAS



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