Area Forecast Discussion
Issued by NWS Charleston, WV

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354
FXUS61 KRLX 280555
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
155 AM EDT THU APR 28 2016

.SYNOPSIS...
FRONT STALLED NORTHERN KENTUCKY TO CENTRAL WEST VIRGINIA LIFTS
BACK NORTH OVERNIGHT...THEN WAFFLES BACK/FORTH IN OUR VICINITY
THROUGH FRIDAY...PROVIDING ROUNDS OF SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH TODAY/...
UPDATE...
TWEAKED POP GRIDS A BIT...KEEPING HIGHER POPS ACROSS THE SOUTH
THIS EVENING ALONG AND SOUTH OF STALLED FRONTAL BOUNDARY. KEEPING
AN EYE ON TRENDS/PRECIPITATION AMOUNTS THIS EVENING. OFFICE
RECEIVED ABOUT 0.25 INCHES IN A 15-20 MINUTE PERIOD THIS EVENING.
A BIT CONCERNED ABOUT COUNTIES TO OUR NORTH AND EAST THIS EVENING
AND OVERNIGHT...WHERE HEAVIER RAINS FELL YESTERDAY. WILL CONTINUE
TO MONITOR...AND ISSUE ANY WATER HEADLINES AS DEEM NECESSARY.

PREVIOUS DISCUSSION FOLLOWS...
AS OF 18Z...STALLED SHALLOW SURFACE FRONT NEAR HTS-CRW TO N OF
BKW. DIFFICULT POP AND QPF FORECAST TO SAY THE LEAST. NOT ENOUGH
CONFIDENCE...AT 18Z...TO GO WITH ANY WIDESPREAD FLASH FLOOD WATCH
OVERNIGHT. DO NOT EXPECT CONVECTION TO ALIGN WITH THE FLOW LIKE
YESTERDAY...BUT STILL HAVE LOCALIZED PROBLEMS. SO IF THESE
DOWNPOURS HIT THE WETTER AREAS FROM LAST NIGHT...COULD SEE
FLOODING. WE WILL CONTINUE TO MONITOR FOR ANY POSSIBLE FFA FOR
TONIGHT.

WILL INSERT SOME HEAVY RAIN FOR OVERNIGHT...AS PRECIPITABLE WATER
INCREASES TO AROUND 1.25 TO 1.5 INCHES...BEFORE TRENDING DOWN AGAIN
LATE THURSDAY.

THINKING SCATTERED CONVECTION DEVELOPS THIS AFTERNOON NEAR THE FRONT
AND SOUTH.  THEN THE MID LEVEL DISTURBANCE APPROACHES 00Z TO 06Z
WITH STEERING FLOW AND LOW LEVEL FLOW BACKING AHEAD OF IT.  12Z MODEL
SOLUTIONS SEEM A BIT SLOW...COMPARED TO THE 18Z RADAR...LIFTING THE
DISTURBANCE NORTHEAST.

SO MORE DEVELOPMENT OVERNIGHT FROM SOUTHWEST TO NORTHEAST...ESPECIALLY
IN THE OHIO VALLEY COUNTIES.

WILL BASE FORECAST ON THE FRONT LIFTING TOWARD THE ROUTE 50 CORRIDOR
BY 12Z THURSDAY.  AS A RESULT...WILL INCREASE MAX TEMPERATURE A BIT
IN THE NORTH ON THURSDAY...BUT A SHARP GRADIENT AS YOU VENTURE
FURTHER NORTH.  HAVE POPS DECREASING IN THE MORNING AS THE MID LEVEL
SUPPORT PULLS NORTH.

MORE INSTABILITY DEVELOPS ON THURSDAY AFTERNOON...COMPARED TO
TODAY...OVER CENTRAL AND SOUTHERN COUNTIES DESPITE THE LOWER
PRECIPITABLE WATER.  SO DIURNAL CONVECTION SHOULD REFIRE...WITH
POSSIBLE SEVERE.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
ALL MODELS SHOW A FINAL WAVE SLIDING THROUGH THURSDAY NIGHT ALONG
THE SURFACE BOUNDARY THAT HAS BEEN LINGERING IN THE REGION MOST OF
THE WEEK. INCREASED POPS TO LIKELY ACROSS THE NORTH WITH THIS. THE
HIGHER RESOLUTION OF THE NAM EVEN SHOWS A DECENT VORT MAX CROSSING
DURING THIS TIME. OTHERWISE...PRECIPITATION TAPERS OFF FROM WEST TO
EAST LATE THURSDAY NIGHT INTO FRIDAY...LINGERING THE LONGEST ACROSS
THE MOUNTAINOUS COUNTIES OF WV. SO...MUCH OF FRIDAY THROUGH FRIDAY
NIGHT LOOKS DRY...BEFORE MOISTURE BEGINS TO INCREASE AGAIN SATURDAY
AS A SURFACE LOW MOVES THROUGH THE SOUTHERN PLAINS. SPED UP POPS
WITH THIS FEATURE PRETTY GOOD...AND MAY EVEN STILL BE A LITTLE SLOW
BASED ON 12Z MODEL RUNS. MINIMAL CHANGES MADE TO TEMPERATURE
FORECAST. BIGGEST CHANGE WAS TO GO A COUPLE DEGREES WARMER FRIDAY
NIGHT WITH CLOUDS ALREADY ON THE INCREASE BY THE PREDAWN HOURS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
UNSETTLED WEATHER IS LIKELY TO START THE PERIOD AS YET ANOTHER
SOUTHERN STREAM WAVE PUSHES IN. THIS IS LIKELY TO BRING ANOTHER
COPIOUS ROUND OF SHOWERS AND THUNDERSTORMS TO THE AREA...AS
SURFACE LOW PRESSURE TRACKS THROUGH THE AREA ON SUNDAY. THE LOW IS
ONLY PROGGED TO BE NEAR STANDARD ATMOSPHERE MSLP...BUT DECENT
MOISTURE INFLOW ON 40 KTS MID LEVEL FLOW...AND UPPER DIVERGENCE
COULD LEAD TO STRONG THUNDERSTORMS AND POSSIBLE EXCESSIVE
RAINFALL.

MODELS CONCUR ON THE WEATHER SETTLING DOWN EARLY NEXT WEEK...AS
THE NORTHERN STREAM DOMINATES...SENDING CANADIAN HIGH PRESSURE
THROUGH THE MIDDLE OHIO VALLEY AND CENTRAL APPALACHIANS. WAS A
BIT LEERY IN TRENDING DRIER INTO THE MIDDLE OF NEXT WEEK...AND
THE 12Z ECMWF SURE ENOUGH THROWS A MONKEY WRENCH BACK INTO THE
FORECAST...WITH YET ANOTHER SOUTHERN STREAM WAVE ON TUESDAY...AND
THE NORTHERN STREAM NOT BECOMING A FACTOR UNTIL LATE IN THE
PERIOD.

TEMPERATURES CLOSE TO THE LATEST GUIDANCE AND BLENDS...A LITTLE
LOWER ESPECIALLY ON LOWS EARLY TO MID WEEK...OTHERWISE CLOSE TO
PREVIOUS PACKAGE. HOWEVER...MODEL VARIATION ON THE POSITION OF THE
FRONT AND WAVES ALONG IT COULD LEAD TO LARGE BUST POTENTIAL.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
DECAYING LINE OF THUNDERSTORMS NOW PUSHING INTO THE NORTHEAST
KENTUCKY REGION TOWARDS HTS...AND A LEADING BATCH OF SHOWERS AND
THUNDERSTORMS MOVING NORTHEASTWARD FROM SOUTHEAST KENTUCKY INTO
THE COAL FIELDS TOWARDS CRW.

CRW...THINKING IS THAT AN OUTFLOW BOUNDARY VISIBLE ON RADAR
IMAGERY AHEAD OF THE AFOREMENTIONED SHOWERS/STORMS WILL BRING THE
VISIBILITIES FROM IFR TO MVFR WITH A MODEST 5 TO 10 KT
WIND...LIKELY OUT OF THE SOUTHWEST SHORTLY AFTER 06Z. ONLY USING
VCTS GIVEN THE OVERALL DECAYING NATURE OF THE CONVECTION TONIGHT.

OVERALL...THE CONVECTIVE TREND CONTINUES TODAY...BUT THE BETTER
FORCING PUSHES NORTH OF THE AREA BY THIS EVENING...TAKING THE
HIGHEST CHANCES OF SHOWERS AND THUNDERSTORMS WITH IT.

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

FORECAST CONFIDENCE: LOW.

ALTERNATE SCENARIOS: TIMING OF CONVECTION...AND ASSOCIATED
RESTRICTIONS COULD VARY FROM CURRENT 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                              THU 04/28/16
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  M    M    M    M    M    M    M    M    M    M    M    H
HTS CONSISTENCY  L    L    L    M    M    L    L    M    M    M    H    H
BKW CONSISTENCY  H    H    H    H    H    M    M    M    M    M    M    H
EKN CONSISTENCY  M    L    L    L    L    L    L    L    L    M    M    M
PKB CONSISTENCY  H    H    H    H    M    M    M    M    M    M    M    M
CKB CONSISTENCY  M    M    M    M    M    M    L    L    M    M    M    M

AFTER 06Z FRIDAY...
IFR POSSIBLE IN ROUNDS OF SHOWERS AND THUNDERSTORMS THURSDAY NIGHT
INTO FRIDAY. IFR POSSIBLE SATURDAY INTO SUNDAY WITH ADDITIONAL
ROUNDS OF SHOWERS AND THUNDERSTORMS.

&&

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

&&

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



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