Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 170531
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
131 AM EDT SUN AUG 17 2014

.SYNOPSIS...
HIGH PRESSURE EXITS EARLY TONIGHT. FRONTAL SYSTEM MEANDERS NEAR THE
AREA SUNDAY/MONDAY. LOW PRESSURE CROSSES MONDAY NIGHT. WEAK DISTURBANCES
KEEP BOUNDARY NEARBY...AND WEATHER UNSETTLED...THROUGH WORK WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
1010 PM UPDATE...BASED ON 00Z NAM...HRRR...RAP...RAISED POPS
ACROSS SW IN RESPONSE TO AREA OF LIGHT SHOWERS MOVING INTO EASTERN
KY. STILL EXPECT PRECIP TO DEVELOP ACROSS THE NORTH AS ENTRY
REGION OF UPPER LEVEL JET STREAKS MOVE OVER EARLY SUNDAY MORNING.

PREVIOUS DISCUSSION...
A TALE OF TWO STREAMS.

A DIFFICULT FORECAST THROUGH SUNDAY AS OUR AREA WILL BE ON THE EDGE
OF TWO STREAMS OF FLOW ALOFT. ONE STREAM IS THE NORTHWEST FLOW
AROUND A DEEP EASTERN CANADIAN UPPER LOW AND THE OTHER IS A MORE
WESTERLY FLOW ORIGINATING FROM THE PACIFIC. WITHIN THE NORTHERN
STREAM IS A VIGOROUS SHORT WAVE AND COOL FRONT TO ROTATE SOUTHEAST
THROUGH NEW ENGLAND. WHILE THIS FRONTAL SYSTEM WILL NOT REACH OUR
AREA...MODELS DO SHOW A JET STREAK DROPPING DOWN WITH THIS
SYSTEM...PUTTING THE NORTHERN PART OF OUR AREA IN THE RIGHT ENTRANCE
REGION OF THIS JET LATE TONIGHT AND EARLY SUNDAY. AT THE SAME
TIME...WITHIN THE MORE SOUTHERN STREAM OF WESTERLY FLOW ALOFT IS A
VIGOROUS UPPER LOW OVER THE MID MISSISSIPPI VALLEY SLOWLY MOVING
EASTWARD. MODELS SHOW DEEP MOISTURE FROM THE UPPER LOW WILL PUSH
EAST ACROSS THE AREA LATER TONIGHT AND SUNDAY WITH PW`S ABOVE 1.5
INCHES. THERE IS A TIME LATE TONIGHT AND EARLY SUNDAY WHERE THE
UPPER JET AND DEEP MOISTURE INTERACT...MAINLY ACROSS THE
NORTHEASTERN THIRD OF THE AREA. HOWEVER...THE MODELS ARE VERY
DIFFERENT AND CHANGEABLE ON THE QPF FIELDS SO THAT THE BEST WAY TO
HANDLE THIS UNCERTAINTY FOR NOW IS TO RANGE FROM HIGH CHANCE NORTH
TO NO POPS FAR SOUTH. DURING SUNDAY...WITH A MOIST AND INCREASINGLY
UNSTABLE ATMOSPHERE OVER THE AREA...WILL INCLUDE CHANCE POPS
EVERYWHERE FOR THE AFTERNOON...BUT AGAIN DIFFICULT TO PINPOINT BEST
CHANCE GIVEN LACK OF UPPER/LOW LEVEL FOCUS MECHANISM AND QUITE A FEW
CLOUDS. TEMPERATURES WILL GET BACK INTO THE 80S SUNDAY...AS SOME
BREAKS IN THE CLOUDS ARE EXPECTED...AND IT WILL FEEL MORE HUMID. ANY
POTENTIAL WATER PROBLEMS WOULD LIKELY BE AFTER THIS TIME
PERIOD...BUT THIS IS ALSO UNCERTAIN. THUS...NO FLOOD WATCHES AT THIS
TIME...WILL CONTINUE MENTION IN HAZARDOUS WEATHER PRODUCT.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FIRST WAVE OF MANY SYSTEMS ARRIVE ALBEIT IT IS A BIT OF A SPLIT
SYSTEM. REGARDLESS POP CHANCES INCREASE INTO MONDAY MORNING BEFORE
PEAKING MONDAY EVENING. LATEST GFS ENSEMBLES HAVE BACKED OFF A BIT
ON THE 06Z TUE PERIOD...BUT BROADEN OUT THE TIME SPAN OF WHICH
PRECIP OCCURS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
RIGHT ON THE HEELS OF THE MON/TUE SYSTEM ANOTHER SYSTEM ARRIVES ON
WEDNESDAY MORNING...LUCKILY THE ENERGY QUICKLY LIFTS TO THE NORTH
LEAVING DRIBBLES AND DRABS FOR MOST OF WEDNESDAY.

ON THURSDAY YET ANOTHER SYSTEM ARRIVES...BUT BY THIS TIME JUST BROAD
BRUSHED AREA WITH HIGHER POPS AS TIMING IS LIKELY THROWN OUT THE
WINDOW BY THIS TIME IN SUCH AN ACTIVE PATTERN. MODELS CONTINUE TO
INDICATE MORE IMPULSES STREAMING THROUGH BY NEXT WEEKEND.

RIDGING FINALLY STARTS TO BUILD NEXT SUNDAY.

&&

.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS THIS EVENING...ALTHOUGH PATCHY MVFR/IFR FOG
CANNOT BE COMPLETELY RULED OUT...GENERALLY AFTER 08Z IN SHELTERED
RIVER VALLEYS. OTHERWISE...CLOUDS WILL CONTINUE TO THICKEN AND
LOWER AS A SERIES OF DISTURBANCES MOVE INTO THE REGION. EXPECT
SHOWERS AND THUNDERSTORMS TO DEVELOP...MAINLY AFTER 15Z...CREATING
BRIEF MVFR CONDITIONS. OUTSIDE OF SHOWERS/STORMS...EXPECTING
MAINLY VFR CONDITIONS WITH LIGHT SURFACE WINDS. BULK OF CONVECTIVE
ACTIVITY SHOULD WANE AFTER 03Z.

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING/DENSITY OF FOG DEVELOPMENT SATURDAY
NIGHT/SUNDAY MORNING MAY VARY FROM FORECAST. TIMING OF
SHOWERS/THUNDERSTORMS COULD VARY FROM FORECAST.

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 08/17/14
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    M    M    M    M    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    M    M    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    M    M    L    L    L    L    M    M    M    M    M
PKB CONSISTENCY  H    H    H    H    M    M    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 06Z MONDAY...
IFR POSSIBLE SUNDAY NIGHT THROUGH MONDAY IN SHOWERS AND
THUNDERSTORMS...AND IN POST RAIN STRATUS AND FOG MONDAY NIGHT INTO
TUESDAY MORNING.

&&

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

&&

$$
SYNOPSIS...JMV/JW
NEAR TERM...JMV/MZ
SHORT TERM...JW
LONG TERM...JW
AVIATION...SL







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