-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 150811
AFDRLX

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

.SYNOPSIS...
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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.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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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 EXPECTED TO PRECLUDE ANY
MEASURABLE PRECIP. HOWEVER AFTER 06Z THE NEXT S/W TROUGH BEGINS TO
PUSH THROUGH 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.
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&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
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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.
-- End Changed Discussion --

&&

.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 /08Z SATURDAY THROUGH WEDNESDAY/...
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06Z SATURDAY THROUGH 06Z SUNDAY...
RIVER VALLEY FOG AND BR OVERNIGHT AND EARLY THIS MORNING WILL
RAPIDLY BURN OFF BY 12Z-13Z WITH VFR CONDITIONS PREVAILING FOR THE
REMAINDER OF THE VALID PERIOD. MOSTLY SUNNY SKIES TODAY WILL
GRADUALLY 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.


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

FORECAST CONFIDENCE...MEDIUM.

ALTERNATE SCENARIOS: TIMING AND LOCATION OF IFR FOG 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                    SAT 06/15/13
UTC 1HRLY       08   09   10   11   12   13   14   15   16   17   18   19
EDT 1HRLY       04   05   06   07   08   09   10   11   12   13   14   15
CRW CONSISTENCY  L    L    L    L    M    H    H    H    H    H    H    H
HTS CONSISTENCY  L    L    L    M    M    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    L    L    L    H    H    H    H    H    H    H
PKB CONSISTENCY  L    L    L    H    M    H    H    H    H    H    H    H
CKB CONSISTENCY  L    L    L    M    H    H    H    H    H    H    H    H

AFTER 06Z 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...JMV/50/SL
SHORT TERM...ARJ
LONG TERM...FB
AVIATION...50