AP-NC--ROA-NC NW Area Forecast Discussion, NC

000

FXUS61 KRNK 151106

AFDRNK

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE BLACKSBURG VA

706 AM EDT WED JUL 15 2015

.SYNOPSIS...

A WEAK COLD FRONT WILL CROSS THE REGION FROM THE NORTHWEST TODAY

BEFORE PASSING OFFSHORE THIS EVENING. HIGH PRESSURE FOLLOWING THE

FRONT WILL BUILD NORTH OF THE REGION LATER TODAY...REACHING THE

MID ATLANTIC COAST THURSDAY NIGHT INTO FRIDAY. THIS SHOULD BRING

SOMEWHAT COOLER AND LESS HUMID AIR TODAY AND TONIGHT...BEFORE

MOISTURE RETURNS BY THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...

AS OF 225 AM EDT WEDNESDAY...

QUIET WEATHER TO FINALLY RETURN OVER THE NEXT 24 HOURS AS THE

STRONG UPPER TROUGH ACROSS THE MID ATLANTIC SWINGS BY TO THE EAST

THIS MORNING ALLOWING THE TRAILING SURFACE COLD FRONT TO CROSS THE

REGION BY LATER THIS AFTERNOON. THIS SHOULD ALLOW DRIER AIR ALOFT

BACK ACROSS THE UPPER MIDWEST TO ADVECT EAST INTO THE AREA THROUGH

THE DAY WHILE SURFACE HIGH PRESSURE BUILDS OFF TO THE NORTH.

HOWEVER MODELS SUGGEST THAT THE BOUNDARY LAYER WILL BE SLOW TO DRY

GIVEN UPSLOPE NW FLOW BEHIND THE FRONT OVER THE NW...AND LINGERING

DEEPER MOISTURE JUST TO THE EAST UNDER THE UPPER COLD POOL. THIS

ALONG WITH HEATING OF THE VERY MOIST SURFACE MAY BE ENOUGH TO POP

ISOLATED SHRA/TSRA ESPCLY FAR EASTERN SECTIONS AND PERHAPS WEST

AFTER EARLY RESIDUAL SPOTTY SHOWERS END THIS MORNING. EXPECT LESS

COVERAGE IN BETWEEN GIVEN NW FLOW ALONG AND OFF THE BLUE RIDGE SO

BASICALLY GOING WITH A SHOTGUN/SCATTERED 20-30 POP SCENARIO MOST

AREAS EXCEPT LESS SOUTHERN SECTIONS AND IN THE IMMEDIATE LEE OF

THE RIDGES. CLOUDS ALSO TRICKY ALONG WITH TEMPS AS POTENTIAL FOR

CU TO FILL BACK IN WITH INITIAL HEATING DESPITE DRYING ALOFT AND

THEN ERODE LATER WITH DRY ENTRAINMENT FROM MIXING/SUBSIDENCE. THUS

TRENDED WITH MORE CLOUDS FAR WEST AND OVER THE NE...WHILE LEANING

TEMPS A LITTLE MORE TOWARD THE COOLER MAV MOS OUTSIDE OF THE SE

GIVEN DECENT JULY COOL ADVECTION WEST ON GUSTY WESTERLY WINDS...AND

POSSIBLY MORE CLOUDS AT TIMES.

APPEARS DRY WEATHER WILL PREVAIL OVERNIGHT BUT CLOUDS REMAIN AN ISSUE

AS THE LOW LEVEL FLOW TURNS MORE NE AROUND THE HIGH TO THE NORTH LATE.

WITH THE HIGH CENTERED SO FAR NORTH...WONT BE ABLE TO KEEP DEWPOINTS

QUITE AS LOW AS EARLIER EXPECTED GIVEN WEAK DRY ADVECTION WHICH MAY

ALSO ALLOW TRAPPED STRATO-CU TO FILL BACK IN ESPCLY ALONG THE MOUNTAINS

OVERNIGHT. THINK THE TYPICAL NAM MOIST BIAS AGAIN IN PLAY BUT COULD SEE

ENOUGH TO GO PC BUT WITHOUT POPS OVERALL. BUMPED UP LOWS A FEW DEGREES

MOST SPOTS PER LINGERING MOISTURE AND SOME CLOUDS. THIS SHOULD KEEP

MOST IN THE MID/UPPER 60S FOR LOWS WITH ONLY THE DEEPER VALLEYS SEEING

ANY UPPER 50S TO LOWER 60S UNLESS SKIES STAY CLEAR IN SPOTS LONGER.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...

AS OF 250 AM EDT WEDNESDAY...

FOR THURSDAY AND FRIDAY...UPPER LEVEL RIDGING OVER THE WESTERN GULF

STATES WILL GRADUALLY EXPAND EASTWARD THROUGH THE END OF THE

WORKWEEK...RESULTING IN BUILDING 500MB HEIGHTS FOR THE MID ATLANTIC

REGION. COMBINE THIS WITH HIGH PRESSURE IN THE LOW LEVELS SHIFTING

FROM THE EASTERN GREAT LAKES ON THURSDAY...ACROSS NEW ENGLAND AND

OUT TO SEA ON FRIDAY...AND WE CAN EXPECT ANY SHOWER AND THUNDERSTORM

ACTIVITY TO REMAIN ISOLATED TO WIDELY SCATTERED...DISORGANIZED...

AND DRIVEN STRICTLY BY DAYTIME HEATING. ANY RAINFALL WHICH DOES FORM

WILL NOT LINGER LONG PAST SUNSET. EAST NORTHEASTERLY WINDFLOW AROUND

THE HIGH WILL KEEP AFTERNOON HIGHS ON THURSDAY RANGING FROM THE LOW

80S/A FEW UPPER 70S ACROSS THE MOUNTAINS...TO THE MID 80S ACROSS THE

PIEDMONT. WINDS WILL SHIFT SOUTHERLY BY FRIDAY AFTERNOON AS THE HIGH

EXITS THE AREA...ALLOWING TEMPERATURES TO BE 3 TO 5 DEGREES WARMER

AREAWIDE.

SHOWER AND THUNDERSTORM CHANCES WILL INCREASE AGAIN ON SATURDAY AS A

COLD FRONT SINKS SOUTHWARD FROM THE GREAT LAKES. SHOWERS AND

THUNDERSTORM ACTIVITY IS EXPECTED TO BE PULSEY IN NATURE...HOWEVER

STRONGER HEATING AND HIGHER DEWPOINTS AS MOISTURE POOLS SOUTH OF THE

BOUNDARY WILL SUPPORT INCREASED INSTABILITY...MAKING FOR A SLIGHTLY

BETTER CHANCE THAT ONE OR TWO STORMS WILL INTENSIFY TO SEVERE LEVELS

DURING THE AFTERNOON AND EVENING. MOST RAINFALL WILL FADE AFTER

SUNSET WITH THE LOSS OF HEATING...ALTHOUGH CANNOT COMPLETELY RULE

OUT A FEW SHOWERS LINGERING SATURDAY NIGHT. EXPECT HIGHS TO RANGE

FROM THE MID 80S WEST...TO THE LOW 90S EAST.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...

AS OF 130 PM EDT TUESDAY...

DURING THIS PORTION OF THE FORECAST WE WILL RETURN TO A WETTER

PATTERN...ONE NOT TOO UNLIKE WHAT HAS BEEN THE NORM FOR THE FIRST

HALF OF JULY. THE NORTHERN JET WILL PLAY A GREATER ROLE IN OUR

WEATHER PATTERN...BRINGING SHORTWAVE AFTER SHORTWAVE ACROSS THE TOP

OF THE UPPER RIDGE AXIS. THIS WILL HAVE THE AFFECT OF RETROGRADING

THE CENTER OF THE RIDGE BACK TO THE MIDDLE MISSISSIPPI VALLEY WITH

NORTHWEST FLOW AGAIN THE DOMINANT STEERING FLOW ACROSS OUR REGION.

LOOK FOR A RETURN OF DAILY SHOWERS AND THUNDERSTORMS. SOME TIME

PERIODS WILL HAVE A GREATER COVERAGE WITH THE POTENTIAL FOR

THUNDERSTORM COMPLEXES TO AGAIN HEAD INTO OR THROUGH THE REGION.

WHILE TIMING WILL LIKELY CHANGE...THE LATEST GUIDANCE OFFERS A

SOLUTION OF TUESDAY OR TUESDAY NIGHT AS THE MOST LIKELY TIME FRAME

FOR THESE.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...

AS OF 640 AM EDT WEDNESDAY...

MVFR TO IFR CONDITIONS PREVAIL ACROSS THE WESTERN FAR WESTERN

SITES EARLY THIS MORNING ASSOCIATED WITH THE COMBINATION OF

UPSLOPE LOW CLOUDS AND THE UPPER COOL POOL PASSING TO THE NORTH.

EXPECT THESE CIGS TO PERSIST THROUGH MUCH OF THE MORNING WITH

ISOLATED LIGHT SHOWERS OR SPRINKLES ALSO POSSIBLE MAINLY AROUND

KBLF/KLWB THROUGH MID MORNING. OTRW SHOULD SEE OVERALL VFR PREVAIL

FROM KROA EAST THROUGH MIDDAY WHILE CLOUDS SLOWLY ERODE AND LIFT

OVER THE WEST WITH HEATING.

ALSO A WEAK COLD FRONT WILL CROSS THE REGION DURING THE DAY WITH

DRYING TAKING PLACE ALOFT WHILE THE LOWER LEVELS REMAIN A LITTLE

MORE MOIST AS HIGH PRESSURE BUILDS TO THE NORTH AND TURNS THE FLOW

MORE NORTH/NE LATE. THIS MAY KEEP SOME DEGREE OF CLOUD COVER

EITHER IN PLACE OR REDEVELOPING UNDER THE PASSING UPPER SYSTEM TO

THE NE OUT EAST...AND WITH UPSLOPE OVER THE WEST. MAY ALSO TAKE

UNTIL AFTERNOON FOR SPOTS LIKE KBLF TO BOUNCE BACK TO VFR GIVEN

THE WIDESPREAD STRATO-CU ATTM AND THEN FILLING IN OUT EAST WITH

HEATING. SHOWER COVERAGE LOOKS TOO SPOTTY TO INCLUDE MENTION SO

LEAVING OUT FOR NOW. OTRW APPEARS ALL LOCATIONS SHOULD IMPROVE TO

A SCTD-BKN 3-5K LAYER THIS AFTERNOON AT THIS POINT.

LOW CONFIDENCE WITH CLOUDS AND POSSIBLE FOG OVERNIGHT AS GUIDANCE

SHOWING STRATO-CU FILLING IN UNDER LIGHT MAINLY EASTERLY FLOW JUST

ABOVE THE SURFACE. THIS COULD ALLOW FOR MORE IN THE WAY OF MVFR

CIGS WITH POSSIBLE MVFR IN FOG IF CLOUDS ARE LESS. THINK WITH ANY

CLEARING LATE THAT KLWB WILL LIKELY DROP TO LIFR IN FOG/STRATUS

WITH PATCHY IFR/MVFR FOG POSSIBLE AT KBCB...AND PERHAPS KBLF WITH

RENEWED UPSLOPE FLOW. KLYH/KROA COULD ALSO LOWER TO MVFR IN LOWER

STRATO-CU CIGS AFTER MIDNIGHT WITH KDAN STAYING MOSTLY VFR OUTSIDE

OF ANY PATCHY FOG.

EXTENDED AVIATION DISCUSSION...

SHOULD RETURN TO VFR THURSDAY INTO FRIDAY AS LOW LEVEL MOISTURE

MIXES OUT AND A MORE SOUTHERLY TRAJECTORY DEVELOPS. CANNOT RULE

OUT SOME WIDELY SCATTERED AFTERNOON AND EVENING SHOWERS...BUT NOT

EXPECTING ANYTHING ORGANIZED FOR THE LATER HALF OF THE WEEK.

WITH OPPORTUNITY FOR CLEARING TO TAKE PLACE AT NIGHT...WILL HAVE

SOME MORNING FOG/LOW CLOUDS ISSUES IN THE MOUNTAIN VALLEYS...AND

GROUND FOG FOR THE LOW LYING AREAS OF THE FOOTHILLS AND PIEDMONT.

OVERALL CONDITIONS HOWEVER SHOULD BE MAINLY VFR.

THE CHANCE OF SHOWERS AND THUNDERSTORMS RETURNS TO THE REGION ON

SATURDAY AND SUNDAY. MVFR CONDITIONS ARE POSSIBLE WITH ANY OF THE

STORMS. OTHERWISE VFR CEILINGS AND VISIBILITIES ARE EXPECTED.

&&

.EQUIPMENT...

AS OF 1000 AM EDT TUESDAY...

NOAA WEATHER RADIO STATION WXM72 IN HINTON WEST VIRGINIA...

OPERATING ON A FREQUENCY OF 162.425 MEGAHERTZ...IS EXPERIENCING

INTERMITTENT OUTAGES. TECHNICIANS ARE ADDRESSING THE PROBLEM.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...

VA...NONE.

NC...NONE.

WV...NONE.

&&

$$

SYNOPSIS...JH

NEAR TERM...JH

SHORT TERM...NF

LONG TERM...DS

AVIATION...AMS/JH/PM/WP

EQUIPMENT...

Delivered by Weather Underground Inc. Wed Jul 15 2015 7:07AM EDT