National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 221821
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
221 PM EDT WED MAY 22 2013

.SYNOPSIS...
A COLD FRONT CROSSES LATE TONIGHT...FOLLOWED BY ANOTHER LATE
THURSDAY.  UPPER LOW CROSSES EARLY FRIDAY...FOLLOWED BY HIGH
PRESSURE...WITH COOLER AND DRIER AIR...FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --
TRACKING ANOTHER MID LVL WAVE MOVING NE ACROSS CENTRAL OH/KY AS
UPR TROF DROPS DOWN INTO UPR MS VALLEY. MOST OF HI RES
MDLS...RUC...AND NAM SEEM TO HAVE A GRASP ON THIS FEATURE AS IT
HEADS ACROSS CWA INTO THIS AFTN. USED LLVL MOISTURE CONVERGENCE
COUPLED WITH MID LVL LIFT ALONG WITH CURRENT SATELLITE TRENDS FOR
TIMING. CAP OVER AREA ERODING CURRENTLY JUST AS THIS FEATURE WILL
BE MOVING INTO W AND S ZONES. AS SUCH BEGIN TO RAMP UP POPS ACROSS
PORTIONS OF NE KY AND W LOWLANDS NEXT HR OR TWO...OVER TO KANAWHA
VALLEY BY 20Z...WITH LKLY POPS...WITH SCT WORDING UP TO THAT
POINT. NOT SURE HOW MUCH DEVELOPMENT REACHES INTO SE OH OR ALONG
OH RVR UP N. THUS HAVE ONLY LOW POPS THERE INITIALLY. OTHER AREA
OF CONVECTIVE INITIALIZATION ACROSS MUCH E RIDGES OF MTNS DOWN TO
SW VA AIDED WITH SOME SE UPSLOPE FLOW. IN FACT MDLS INDICATE THIS
CONVECTION MAY TRY TO COME OFF THE RIDGES TOWARD I79 CORRIDOR TO
COINCIDE WITH CONVECTIVE BAND MOVING THRU KANAWHA VALLEY.
THUS...HAVE SOME CAT POPS IN THIS AREA BY 21Z. MAY SEE A LULL W
ZONES ONCE THIS MOVES THRU UNTIL COLD FRONT APPROACHES BY 00Z AS
BL TRIES TO STABILIZE. QUESTION THEN BECOMES HOW ACTIVE IS FRONT
AS IT MOVES THRU TONIGHT. THINK SE OH STANDS TO SEE GREATEST
COVERAGE OF FRONTAL PCPN SHOULD AFTN ACTIVITY STAY MOSTLY E AND S
OF THEM. WILL ROLL WITH MDL CONSENSUS WITH LKLY POPS SLOWLY
SLIDING E OVERNIGHT WITH FRONT. GRADUALLY DECREASE THUNDER AS
WELL. SFC FRONT BECOMES RATHER DIFFUSE AND HARD TO FIND OVERNIGHT.
SOME LOW STRATUS EXPECTED WITH BOUNDARY OVERNIGHT IN ADDITION TO E
SLOPES. THIS MAY MITIGATE DENSE FG. HOWEVER...ACROSS W ZONES MAY
SEE SOME PARTIAL CLEARING WHICH MAY ALLOW FOR SOME LATE FG TO SET
IN.

SPC CONT SLIGHT RISK OVER MUCH OF AREA FOR THIS AFTN/EVE. MDL
SOUNDINGS LOOK SIMILAR TO YESTERDAY. SHOULD SEE SOME DECENT ML CAPE
ACROSS THE AREA WITH SLIGHTLY BETTER FLOW ALOFT COMPARED TO
YESTERDAY. THINK WIND IS GREATEST CONCERN AGAIN TDY WITH DOWNDRAFT
CAPE AND SFC-H7 DELTA THETA VALUES INDICATIVE OF DAMAGING WIND
POTENTIAL. FRZ LVL LOOKS TO BE ARND 12K WITH WETBULB HEIGHTS CLOSER
TO 10K...SO CANT RULE OUT SOME LARGER HAIL. CODED UP THE STRONG
ATTRIBUTES IN WX GRIDS FOR THIS AFTN.

PWATS ARND 1.5 AGAIN TDY BUT STORM MOTION/SPEED MAY MITIGATE
WATERN CONCERNS IN SOGGY COAL FIELDS/SW VA/MTNS. WILL MONITOR
TRENDS THOUGH SHOULD RIDGE TOPS GET GOING EARLY.

UPR TROF TRACKS E ON THU WITH POTENTIAL SECONDARY FRONT AS WELL.
MAY SEE A COUPLE BANDS OF PCPN MOVE THRU WITH SOME LULLS IN
INBETWEEN...ESPECIALLY IN MORNING. SFC INSTABILITY A LITTLE LOW
BUT STEEPENING LAPSE RATES MAY BRING A SMALL HAIL CONCERN IN THE
AFTN.

INHERITED TEMPS OVERALL LOOKED RATHER GOOD AND ONLY NEEDED SOME
MINOR TWEAKS. SHOULD BE COOLER TOMORROW AS UPR HEIGHTS FALL.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
UNSETTLED WEATHER CONTINUES ON THURSDAY...AND PART OF FRIDAY...AS
UPPER TROUGH AND SURFACE COLD FRONT SWEEP ACROSS THE REGION. THIS
WILL KEEP A CHANCE FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR
THE START OF THE SHORT TERM PERIOD. STILL COULD BE SOME STORMS ON
THURSDAY THAT MAY CONTAIN SOME STRONGER WIND GUSTS AS THERE WILL
STILL BE MODERATE WINDS ALOFT...BUT OVERALL INSTABILITY IS
WEAK...AND SO SEVERE RISK IS LOW.

DRIER...COOLER...NORTHWESTERLY FLOW PATTERN WILL TAKE HOLD FOR
FRIDAY THROUGH SATURDAY AS THE UPPER TROUGH PUSHES EAST. DID ELECT
TO LOWER TEMPS SLIGHTLY DURING THIS PERIOD...PARTICULARLY SATURDAY
MORNING...AS GOOD CLEARING...LIGHT SURFACE WINDS EXPECTED AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. MAY BE SOME FOG DEVELOPMENT
ESPECIALLY SATURDAY MORNING UNDER THESE CONDITIONS.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
HAVE GENERALLY FOLLOWED WPC THINKING FOR THIS PORTION OF THE
FORECAST.

HIGH PRESSURE WILL BE IN CONTROL OF THE WEATHER ACROSS THE AREA INTO
SUNDAY NIGHT.  HOWEVER...MODELS SUGGEST A FEW WEAK MID-LEVEL
SHORTWAVE MAY MOVE SOUTHEAST.  BELIEVE AREA SHOULD REMAIN DRY...WITH
A FEW MORE CLOUDS BEGINNING SATURDAY NIGHT

A WARM FRONT WILL THEN DEVELOP AND APPROACH THE REGION ON MONDAY. AS
A RESULT...THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY AND
TUESDAY...MAINLY DURING THE AFTERNOON AND EVENING HOURS.

TEMPERATURES ON SATURDAY SHOULD BE NEAR NORMAL WITH DAYTIME HIGHS IN
THE 70S ACROSS THE LOWLANDS...WITH 60S ACROSS THE HIGHER
ELEVATIONS.  AS THE HIGH PUSHES EAST ON SUNDAY...EXPECT TEMPERATURES
TO WARM TO SLIGHTLY ABOVE NORMAL VALUES MONDAY AND TUESDAY.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
MTN SHRA/TSRA THRU AFTN AIDED BY HEATING AND SE LLVL FLOW. HAVE
TEMPO GROUPS IN FOR MTN SITES FOR IFR VSBY IN CONVECTION.

ELSEWHERE...SCT CONVECTION INCREASING IN COVERAGE THRU AFTN AS A
MID LVL IMPULSE MOVES THRU WITH GREATEST INCREASE PEGGED C
LOWLANDS AND POINTS E. PUT SOME TEMPO GROUPS FOR KCRW WHERE
GREATEST COFIDENCE LIES. SOME DAMAGING WIND GUSTS POSSIBLE IN ANY
STRONGER CONVECTION WHICH WILL HAVE TO BE MONITORED FOR TAFS.
MAXIMIZED COVERAGE ARND 21Z HERE. WILL THEN FOLLOW COLD FRONT
TRAVERSING ACROSS AFTER 00Z FROM W WITH ANOTHER BAND OF SHRA AND
POTENTIAL TSRA WITH BRIEF IFR VSBY POSSIBLE. EXPECT LOW STRATUS TO
DEVELOP OVERNIGHT...SCT OUT ACROSS W BY 12Z. FG TRICKY TONIGHT AND
HIGHLY DEPENDANT ON WHERE IT RA AND ANY STRATUS. FOR NOW...HAVE
GENERAL MVFR VSBY MOST TAF SITES. SHOULD IT CLR OUT W LATE...THEN
SOME PREDAWN DENSE FG MAY DEVELOP FOR KHTS/KPKB.

ANY STRATUS AND/OR FG WILL LIFT BY 13Z WITH LOW END VFR BASED CU
LATE MORNING ON. UPR TROF CROSSES TOMORROW WITH INCREASE ONCE
AGAIN IN SHRA ACTIVITY AND POSSIBLY SOME TSRA.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z
THURSDAY...

FORECAST CONFIDENCE...MEDIUM TO HIGH.

ALTERNATE SCENARIOS: TIMING AND DEGREE OF FLIGHT RESTRICTIONS DUE TO
CONVECTION THIS AFTERNOON AND TONIGHT COULD VARY...AS WELL AS TIMING
AND EXTENT OF DENSE VALLEY FOG OVERNIGHT TONIGHT.

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.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
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    M
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    M
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    M

AFTER 18Z THURSDAY...
IFR CONDITIONS POSSIBLE IN EARLY SATURDAY MORNING.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...ARJ/30
NEAR TERM...30
SHORT TERM...SL
LONG TERM...JSH
AVIATION...30