Area Forecast Discussion
Issued by NWS Sterling, 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 KLWX 300119
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
919 PM EDT SAT AUG 29 2015

.SYNOPSIS...
HIGH PRESSURE REMAINS OVER THE REGION THROUGH THE MIDDLE OF THE
WEEK BEFORE WEAKENING LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
HIGH CLOUDS DISSIPATING/MOVING OUT OF THE AREA THIS EVENING.
MOSTLY CLEAR CONDITIONS BY LATE TONIGHT. HOWEVER...HIGHER SFC
MOISTURE COMPARED TO YESTERDAY WILL RESULT IN A WARMER NIGHT...
LOWS IN THE 60S XCPT L70S IN THE CITIES AND ALONG THE BAY. LGT
FOG LIKELY IN SHELTERED VALLEYS AND PORTIONS OF THE PIEDMONT.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
SUNDAY SAME STORY DIFFERENT DAY - HIGH PRES RMNS OVR THE AREA.
HIGHS 85-90. LOW CHC OF RW/TRW TMRW...ESPECIALLY OVR THE
MTNS...BUT AT THIS TIME OF YR UPR LVL WIND FIELD IS GNRLY PRETTY
LGT...AS IS THE CASE SUNDAY. HENCE SVR THREAT IS NIL.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
BY SUNDAY NIGHT...TROUGH IN THE NORTHERN STREAM INVOF THE EASTERN
GREAT LAKES WILL PROVIDE THE WEAKNESS FOR THE CLOSED LOW WHICH HAS
BEEN RESIDING ON THE CENTRAL GULF COAST TO LIFT NE. WHILE DIURNAL
CONVECTION OVER THE HIGH TERRAIN WILL BEGIN TO WEAKEN DURING THE
EVENING...HAD TO CONTINUE LOW END POPS THROUGH THE NIGHT AS THE
TROUGH APPROACHES FROM THE SOUTHWEST. LOWS WILL BE IN THE 60S WITH
LOWER 70S E OF I-95.

THERE ARE SOME SLIGHT TIMING DIFFERENCES...BUT THE TROUGH SHOULD
LIFT ACROSS THE AREA DURING THE MORNING TO MIDDAY HOURS...SHEARING
OUT AS IT INTERACTS WITH THE NORTHERN STREAM. AT THE
MINIMUM...MONDAY WILL BE A MOSTLY CLOUDY INTERRUPTION TO OUR HIGH
PRESSURE-DOMINATED WEATHER PATTERN. LOW LEVEL MOISTURE AND FORCING
WILL BE POOR...BUT ELECTED TO LEAVE AT LEAST SLIGHT CHANCE POPS
ACROSS THE ENTIRE AREA. THUNDER CHANCES WILL BE MINIMAL WITH THIS
FEATURE. ALSO SHADED HIGH TEMPERATURES A LITTLE LOWER DUE TO THE
CLOUDS...MAINLY IN THE MID 80S.

LATE SUMMER PATTERN RESUMES MONDAY NIGHT INTO TUESDAY...AND IF
ANYTHING...MID/UPPER RIDGING WILL BUILD FURTHER OVER THE EASTERN
CONUS. THIS WILL MEAN RISING TEMPERATURES...WITH MANY AREAS NEAR OR
ABOVE 90 FOR HIGHS. WITHOUT A PROMINENT TRIGGER PRESENT AND POOR MID-
LEVEL LAPSE RATES...ANY DIURNAL CONVECTION WILL BE CONFINED TO THE
MOUNTAINS.

TUE NGT-SAT: HIGH PRES WILL MOSTLY DOMINATE CONDITIONS DURING
THIS PERIOD...WITH SOME UPPER LEVEL SHORTWAVES THAT WILL MOVE
THROUGH OR NEAR OUR AREA. 00Z ECMWF KEEPS OUR CWA DRIER THAN THE
12Z GFS...WITH BOTH MODELS BRINGING PRECIP OVER OR NEAR OUR CWA
NEXT SAT. KEPT A CHANCE OF SHOWERS AND TSTMS DURING THE LATE
AFTN/ERLY EVE EACH DAY BUT MAJORITY OF TIME WL BE DRY. TEMPS WILL
BE FIVE TO TEN DEGREES ABOVE NORMAL FOR ERLY SEPT.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
VFR CONDS XPCTD TNGT AND SUN. MVFR VSBYS LIKELY AT CHO/MRB...MIFG
AT IAD.

UPPER DISTURBANCE PASSES OVER SUNDAY NIGHT-MONDAY...BUT VFR
CONDITIONS SHOULD PREVAIL AND ANY ISOLATED SHOWER SHOULD BE LIGHT.
TUESDAY MORNING WILL PROBABLY REPRESENT THE BETTER OPPORTUNITY FOR
MORNING BR AT MRB/CHO AS SKIES CLEAR. ANY DIURNAL STORMS TUESDAY
AFTERNOON LIKELY STAY WEST OF TERMINALS.

&&

.MARINE...
SLY CHANNELING SURGE WITH GUSTS TO 20 KT CURRENTLY OVER CNTRL AND
NRN MD BAY WATERS WILL CONTINUE TO LIFT NORTH THROUGH THE REST OF
THE EVENING. MARINE WEATHER STATEMENT FOR THESE GUSTS THROUGH
10PM.

TROUGH OF LOW PRESSURE TO THE NORTH WILL TIGHTEN THE PRESSURE
GRADIENT SUNDAY EVENING...AND WHEN COMBINED WITH SOUTHERLY
CHANNELING THERE COULD BE A BRIEF WINDOW FOR SCA CONDITIONS. HOWEVER
HAVE LIMITED FORECAST TO 15 KT FOR NOW DUE TO LOW CONFIDENCE.
WESTERLY FLOW 5-10 KT MONDAY WILL BECOME LIGHTER AND MORE VARIABLE
MONDAY NIGHT AND TUESDAY AS HIGH PRESSURE IS REESTABLISHED.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
UPDATE...JACKSON
PREVIOUS...WOODY!/ADS/IMR


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