-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 151435
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1035 AM EDT SAT JUN 15 2013

.SYNOPSIS...
HIGH PRESSURE BUILDS TODAY. UPPER LEVEL SHORTWAVES COULD PRODUCE
AFTERNOON AND EVENING STORMS SUNDAY. A COLD FRONT CROSSES SUNDAY
NIGHT INTO MONDAY. ANOTHER STRONG SHORTWAVE PASSES TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
FORECAST IS GENERALLY ON TRACK. HOWEVER...MADE SOME TWEAKS TO
HOURLY TEMPS...WINDS AND SKY FOR TODAY TO REFLECT CURRENT TRENDS
AND LATEST GUIDANCE.

630 AM UPDATE...
ONLY CHANGE WAS TO BUMP UP SKY COVER A LITTLE TO REFLECT SOME THIN
HIGH CLOUDS TODAY...WITH HIGH CLOUDS BEGINNING TO STREAM OVERHEAD
FROM THE DECAYING MCV WELL TO THE WEST.

PREVIOUS DISCUSSION...
ALL IN ALL A VERY PLEASANT DAY IS IN STORE FOR THE AREA. SFC HIGH
PRESSURE CURRENTLY LOCATED OVER THE AREA WILL CONTINUE OFF TO THE
SOUTHEAST WITH VERY LIGHT WEST/SOUTHWEST WINDS. FLOW ALOFT BECOMES
INCREASINGLY ZONAL AS UPPER RIDGE OVER THE MIDWEST BREAKS DOWN.
06Z RADAR AND SATELLITE IMAGERY SHOWING A MCV CURRENTLY
PROGRESSING E/SE-WARD OVER IOWA. VORT MAX WITH THIS FEATURE IS
PROGGED TO BE OVER WESTERN OHIO BY 00Z SUN. THIS FEATURE EXPECTED
TO ONLY YIELD AN INCREASE IN HIGH AND MID LEVEL CLOUDS LATE THIS
AFTERNOON AND EARLY EVENING ACROSS THE NORTHWEST ZONES WITH DRY
LLVLS AND A STOUT NEAR-ISOTHERMAL LAYER CAP ABOVE 800MB...WHICH
PREV FCST HAD A GOOD HANDLE ON. INHERITED MAX TEMPS IN THE
LOWER/MID 80S STILL ON TRACK.

00Z SUN-06Z SUN THE FIRST VORT MAX BRUSHES BY THE NORTHERN PART OF
THE FORECAST AREA WITH LITTLE FANFARE FOR AFOREMENTIONED REASONS.
VORT MAX HELPS TO ERODE THE 800MB CAP. DECENT SATURATION 700MB-500MB
WITH VERY LOW AMOUNTS OF ELEVATED INSTABILITY COULD FEASIBLY BE
ENOUGH TO SQUEEZE OUT SOME SPRINKLES ACROSS THE FAR NORTHERN
ZONES...BUT AGAIN DRY AIR BELOW 700MB AND STORM SPEED AROUND 20KTS
EXPECTED TO PRECLUDE ANY MEASURABLE PRECIP. HOWEVER AFTER 06Z THE
NEXT S/W TROUGH BEGINS TO PUSH INTO THE MID-OHIO VALLEY. CONSENSUS OF
MODEL OUTPUT STILL HAS THE TROUGH AXIS WELL WEST OVER NW OHIO/SW
INDIANA AT END OF NEAR-TERM 12Z SUN WITH ACCOMPANYING SFC FRONT
ALSO NW OHIO WESTWARD TOWARDS NORTHERN INDIANA. DEEPER LLVL
MOISTURE NOT ARRIVING UNTIL 12Z SUN AND AFTER. WITH SFC FRONT AND
S/W TROUGH STILL WELL WEST OVERNIGHT AND NO REAL OTHER
IDENTIFIABLE CONVECTIVE TRIGGER...DECIDED TO KEEP POPS RELATIVELY
LOW DURING THE OVERNIGHT PERIOD. WENT ABOVE GUIDANCE ON MINS AND
NUDGED TEMPS UPWARD JUST A BIT TO REFLECT WARM ADVECTION AFTER 06Z
ACROSS THE WEST AND A DECENT CLOUD COVER ACROSS THE AREA...WITH
LOW/MID 60S EXPECTED FOR THE LOWLANDS.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
THE NAM SHOWS ZONAL FLOW AND A SERIES OF VORT MAXES ACROSS THE AREA
EARLY SUNDAY...THE SECOND STRONGEST BY 18Z SUNDAY. THE GFS IS MUCH
WEAKER WITH THIS VORT MAX. THE GFS/ECMWF/CMC AND NAM SUGGEST GOOD
CONFIDENCE ON PCPN IN THEIR QPF FIELDS.

ALTHOUGH THE NAM IS NOTORIOUS FOR OVERESTIMATING DEWPOINTS AND SFC
CAPE IN THE SHORT TERM...IT SHOWS PW NEAR 1.72 INCHES...SFC CAPE
AROUND 1400 J/KG AND DEEP LAYERED SHEAR EXCEEDING 35 KNOTS.
HELICITY MAXIMUM AROUND 120 M2/S2 PER NCEP...AND 60 PERCENT
PROBABILITY OF 200 M2/S2 PER THE SREF ARE NOT IMPRESSIVE.
HODOGRAPHS SHOW UNIDIRECTIONAL SHEAR WITH EQUILIBRIUM LEVELS
AROUND 35 KFEET. SREF SUPERCELL COMPOSITE PARAMETER SHOWS 50
BULLS EYE AT NORTHWEST SECTIONS OF RLX...BETWEEN WV...OH...AND PA
BY 18Z SUNDAY.

THESE CONDITIONS COULD PRODUCE STRONG THUNDERSTORMS...AND PERHAPS
DAMAGING WINDS OF WATER PROBLEMS DEPENDING ON TRAINING OVER THE
SAME AREAS.

FOR MONDAY...THE COLD FRONT PUSHES PCPN TO OUR SOUTHEAST AND
MEANDERS OVER EXTREME SOUTHWEST VA THRU EARLY MONDAY...FOR A
RELATIVELY DRIER DAY.

YET...A SFC LOW PRESSURE SYSTEM DROPS FROM THE GREAT
LAKES...SOUTHEAST INTO SOUTHEAST OH AND WV TUESDAY. THE NAM SHOWS
PC AROUND 1.5 INCHES AND SFC CAPE EXCEEDING 2600 J/KG WITH SFC
DEWPOINTS GREATER THAN 65F. ALTHOUGH NAM COULD BE OVERESTIMATING
DEWPOINTS...BELIEVE IN LOCALLY MAXIMUM FOR THE BEST CAPE TO ALIGN
WEST TO EAST ACROSS SOUTHEAST OH AND WEST VIRGINIA LATE MONDAY
EVENING...BUT UPPER LEVEL SUPPORT DOEST NOT ARRIVE UNTIL NEXT
SHORTWAVE AT H5 06Z TUESDAY. WILL KEEP MONITORING THE UNSETTLED
CONDITIONS MONDAY AND TUESDAY FOR THE LATEST INFORMATION.

PREVIOUS TEMPERATURES LOOKS GOOD...WITH H850 TEMPERATURES AROUND
13C...AND MOISTURE FROM EXPECTED RAINFALL...LEFT THEM SLIGHTLY
HIGHER THAN LATEST MET/MAV NUMBERS THROUGH TUESDAY.

ADJUSTED POPS TO HIGH LIKELY ACCORDING TO THE MOST UNSTABLE AREAS
AND TIMING OF UPPER LEVEL DISTURBANCES MONDAY AND TUESDAY. ADDED
POSSIBLE SEVERE MAINLY FROM HIGHEST CAPE...NORTHERN HALF OF CWA.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
THE UPPER LEVEL FLOW SLOWLY TURNS MORE SOUTHWESTERLY ON TUESDAY AS A
LOW PRESSURE SYSTEM MOVES ACROSS CANADA WITH A TRAILING WEAK COLD
FRONT THROUGH THE FORECAST AREA.  WILL HAVE TO CONTINUE TO MONITOR
MONDAY AND TUESDAY FOR POTENTIAL HYDRO ISSUES.  BY WEDNESDAY HIGH
PRESSURE BEGINS TO BUILD OVER THE CENTRAL UNITED STATES.  THIS WILL
PROVIDE SOME DRYING FOR THE FORECAST AREA.  STILL EXPECT MOISTURE TO
LINGER SO HAVE NOT REMOVED POPS ENTIRELY.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
12Z SATURDAY THROUGH 12Z SUNDAY...
WIDESPREAD SUB-IFR VIS IN RIVER VALLEY FOG EARLY THIS MORNING
WILL RAPIDLY BURN OFF IN THE NEXT HOUR OR TWO...WITH VFR
CONDITIONS PREVAILING FOR THE REMAINDER OF THE VALID PERIOD.
MOSTLY SUNNY SKIES TODAY WILL GIVE WAY TO INCREASING HIGH AND MID
LEVEL CLOUDS DURING THE LATE AFTERNOON AND EVENING TIME FRAME FROM
NORTHWEST TO SOUTHEAST AS THE NEXT DISTURBANCE APPROACHES THE
AREA. WINDS WILL REMAIN LIGHT TODAY FROM THE WEST AND GRADUALLY
SHIFT TO THE SOUTH BY END OF PERIOD WITH SFC LOW PRESSURE TO THE
WEST. THOUGH PATCHY RIVER VALLEY FOG IS POSSIBLE IN THE FAVORED
LOCATIONS TONIGHT...CLOUD COVER AND A STRONGER BOUNDARY LAYER WIND
AFTER 06Z SHOULD KEEP VIS RESTRICTIONS TO A MINIMUM.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...

FORECAST CONFIDENCE...HIGH.

ALTERNATE SCENARIOS: SCATTERING/LIFTING OF LIFR FOG MAY VARY
SLIGHTLY THIS MORNING.

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       14   15   16   17   18   19   20   21   22   23   00   01
EDT 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
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    H    H    H    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 12Z SUNDAY...
IFR POSSIBLE SUNDAY AND MONDAY IN SHOWERS AND STORMS.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...ARJ/50
NEAR TERM...JSH/50
SHORT TERM...ARJ
LONG TERM...FB
AVIATION...50