Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 130554
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
154 AM EDT SUN JUL 13 2014

.SYNOPSIS...
MORE HUMID SOUTHWEST FLOW DEVELOPS OVERNIGHT INTO SUNDAY. CONVECTION
DEVELOPS IN OHIO VALLEY SUNDAY AND LINGERS ON MONDAY. STRONG COLD
FRONT EARLY TUESDAY. UNSEASONABLY COOL WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /THROUGH TODAY/...
145 AM UPDATE...
SLOWED ONSET OF POPS A BIT SUN MORNING...OTHERWISE FCST ON TRACK.

PREV DISCN...
A BIT MORE OPTIMISTIC ON CLOUDS OVERNIGHT...COVER WITH PATCHES OF
MOSTLY MID DECK CLOUDS. SO THE MOON SHOULD STILL BE EVIDENT.

INCREASING LOW LEVEL FLOW IN THE OHIO VALLEY. FOR EXAMPLE 925 MB
FLOW AROUND 10 KNOTS AT 00Z THIS EVENING...SHOULD BE 20 KNOTS AFTER
06Z.  SO TEMPERATURES WILL NOT DROP MUCH.  MANY URBAN AREAS AROUND
70 DEGREES FOR A MINIMUM IN THE WEST.

WITH THAT LOW LEVEL FLOW STILL INCREASING ON SUNDAY...INCREASED OUR
SURFACE WINDS WITH GUSTS NEAR 20 KNOTS.  HAVE WINDS INCREASING
QUICKLY AROUND 12-15Z.

CERTAINLY NOT YOUR TYPICAL DOG DAY MID JULY PATTERN. LOTS OF UPPER
LEVEL DIVERGENCE DOWN THE OHIO RIVER SUNDAY AFTERNOON TO THE SOUTH
OF THE 250 MB JET OVER THE GREAT LAKES.  SO SIMILAR TO TUESDAY THIS
CONVECTION HAS DYNAMICS...NOT THE TYPICAL MID SUMMER
HEATING/BUOYANCY ETC.  THOUGH FLOW AROUND 850 MB LOOKS TO BE SETTING
UP FOR ABOUT 30 KNOTS...A BIT WEAKER THAN THIS PAST TUESDAY.

STILL PICTURING THE CONVECTION TO DEVELOP SW DURING THE LATE DAY AND
INTO THE EVENING INTO THE MOST UNSTABLE AIR OVER THE LOWER OHIO
VALLEY.   LOW LEVEL INFLOW MAY BE PARALLEL TO THAT DEVELOPMENT...
WHICH MAY HINDER INFLOW TO STORMS FURTHER NORTHEAST...UP THE LINKS
IN THE CONVECTIVE CHAIN.

INCLUDED DOWNPOURS AND GUSTY WINDS IN THE GRIDDED HOURLY FORECAST.
OF COURSE MANY SOUTHERN COUNTIES COULD USE SOME RAIN.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
AN UNUSUALLY STRONG AND HIGH AMPLITUDE UPPER TROUGH WILL PUSH A COLD
FRONT ACROSS THE AREA MONDAY NIGHT AND TUESDAY MORNING. WITH
CONTINUED MODEL DIFFERENCES ON TIMING OF THE COLD FRONT...FOLLOWED
HPC THINKING...WHICH PUSHES THE COLD FRONT ACROSS TUESDAY MORNING.
MODELS ARE PERSISTENT ON TWO ORGANIZED BANDS OF CONVECTION WITH THIS
UPPER TROUGH.

FIRST BAND OF CONVECTION WILL LIKELY DROP EAST SOUTHEAST LATER
SUNDAY AND SUNDAY NIGHT AHEAD OF A LEAD SHORT WAVE...WELL OUT AHEAD
OF THE COLD FRONT. WILL TAKE A BLEND OF THE MODELS FOR
TIMING...WHICH BRINGS THE LEADING EDGE INTO SOUTHEAST OHIO SUNDAY
AFTERNOON AND DOWN ACROSS MUCH OF THE AREA SUNDAY NIGHT BEFORE
WEAKENING. VERY WARM AND HUMID AIR ACCOMPANYING THE SHORT
WAVE...WILL BRING A CHANCE OF SEVERE STORMS MAINLY SOUTHEAST OHIO
SUNDAY AFTERNOON AND
EVENING.

SECOND BAND OF CONVECTION WILL BE ALONG AND AHEAD OF THE COLD FRONT
FROM LATER MONDAY INTO EARLY TUESDAY. THIS LEAVES MUCH OF MONDAY FOR
THE ATMOSPHERE TO RECOVER FROM PREVIOUS CONVECTION...ALTHOUGH THERE
WILL BE STORMS SCATTERED ABOUT IN THE CONTINUED VERY WARM AND HUMID
AIR. WITH BETTER UPPER SUPPORT AND THE FRONT...SOME OF THESE STORMS
LATER MONDAY AND MONDAY NIGHT MAY BE SEVERE. CONVECTION ENDS FROM
WEST TO EAST TUESDAY MORNING AS THE FRONT EXITS...WITH MUCH COOLER
AND DRIER CANADIAN HIGH PRESSURE BUILDING IN.

TEMPERATURES WELL INTO THE 80S WITH LOTS OF HUMIDITY MONDAY WILL BE
REPLACED BY TEMPERATURES NOT GETTING OUT OF THE 70S TUESDAY IN THE
DRIER CANADIAN AIR.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY WILL BE DRY AND COOL UNDER CANADIAN HIGH PRESSURE.
THIS WILL CONTINUE TO BE THE RULE OVER MOST OF OUR AREA FOR THE
LATER PORTION OF THE WEEK. HOWEVER...THERE WILL BE A WARMING TREND
BACK INTO THE 80S WITH INCREASING HUMIDITIES BY THURSDAY...AS THE
SURFACE HIGH SHIFTS EAST AND SOUTHEASTERLY FLOW BRINGS LOW LEVEL
MOISTURE BACK. THUS...THERE WILL ALSO BE JUST A SMALL CHANCE OF A
SHOWER OR STORM FOR THE END OF THE WEEK PERIOD IN THE
MOUNTAINS...AIDED BY UPSLOPE COMPONENT OF THE FLOW.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AN APPROACHING COLD FRONT WILL IMPACT THE ARA WITH NUMEROUS
THUNDERSTORMS THIS PERIOD.

INCREASING MID-LEVEL CLOUD WILL PREVENT FOG FOR THE MOST PART
OVERNIGHT...WITH BRIEF IFR POSSIBLE AT EKN.

SHOWERS AND THUNDERSTORMS WILL INCREASE IN AREA COVERAGE FROM NW TO
SE MIDDAY AND AFTERNOON SUNDAY.  BY LATE IN THE DAY...THEY WILL
BECOME NUMEROUS ACROSS THE MIDDLE OHIO VALLEY...WHERE STRONG TO
DAMAGING THUNDERSTORM WIND GUSTS ARE POSSIBLE.  THIS ACTIVITY WILL
SLOWLY WORK SEWD INTO THE CENTRAL APPALACHIANS ON SUNDAY NT.  THE
STORMS MAY WEAKEN A BIT AFTER SUNSET...BUT WILL GENERALLY REMAIN
STRONG INTO THE NT.

BY LATE SUNDAY NT...MVFR TO IFR CONDITIONS DURING AND AFTER THE
SHOWERS AND THUNDERSTORMS WILL BECOME COMMON.  IFR OR WORSE WILL
OCCUR RIGHT UNDER ANY THUNDERSTORM SUNDAY AFTERNOON AND NT.

LIGHT S SFC FLOW OVERNIGHT WILL BECOME SW...FRESHEN AND BECOME A BIT
GUSTY ON SUNDAY AND THEN DIMINISH A BIT SUN NT.  LIGHT SW FLOW ALOFT
OVERNIGHT WILL BECOME MODERATE W TO SW FOR SUNDAY AND SUNDAY NT.
THE THUNDERSTORMS SUNDAY AFTERNOON AND NT CAN BRING DOWN THIS
MOMENTUM ALOFT TO PRODUCE STRONG TO DAMAGING WIND GUSTS.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...

FORECAST CONFIDENCE: MEDIUM TO HIGH.

ALTERNATE SCENARIOS: FOG OVERNIGHT MAY VARY A BIT.  TIMING OF SUNDAY
AFTERNOON AND EVENING CONVECTION COULD VARY.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

DATE                              SUN 07/13/14
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    L    L    L    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 06Z MONDAY...
IFR IN ROUNDS OF STRONG THUNDERSTORMS OVERNIGHT SUNDAY NIGHT THROUGH
MONDAY EVENING...WITH POSSIBLE OVERNIGHT FOG WHERE RAIN FALLS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...KTB/TRM/JMV/26
NEAR TERM...KTB/TRM
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...TRM





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