823
FXUS61 KRLX 071838
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
238 PM EDT TUE JUL 7 2020
SYNOPSIS
HEAT PERSISTS WITH MAINLY DIURNALLY DRIVEN CONVECTION. A COLD
FRONT BREAKS THE HEAT THIS WEEKEND.
NEAR TERM /THROUGH WEDNESDAY/
AS OF 225 PM TUESDAY...
THE HEAT WAVE CONTINUES. AN UPPER LEVEL SHORT WAVE TROUGH, OR
WEAKNESS, WAS HELPING TO FOCUS CONVECTION OVER THE MIDDLE OHIO
VALLEY THIS AFTERNOON. WHILE THAT CONVECTION WILL NOT MAKE IT
EAST OF THE OHIO RIVER, INSTABILITY BUILDING TO 2-3 KJ/KG AND
LIGHT AND VARIABLE FLOW THROUGH THE COLUMN SPELL PULSE POP-UP
SLOW MOVERS WITH HIGH RAINFALL RATES GIVEN PW VALUES OF 1.7-1.8
IN, A LITTLE LESS OVER CENTRAL WV. CONVECTION WAS ALSO BEGINNING
TO FIRE OVER THE HIGHER MOUNTAINOUS TERRAIN ON THE ELEVATED
HEAT SOURCE EFFECT THERE.
RIVER VALLEY FOG IS MOST LIKELY TO FORM OVERNIGHT TONIGHT WHERE
RAIN OCCURS THIS AFTERNOON OR EVENING.
RIDGING MAY BUILD A BIT TO THE NORTH WEDNESDAY AS A REX BLOCK
DEVELOPS, WITH UPPER LEVEL LOW PRESSURE TO THE SOUTH. THIS MAY
HOLD DOWN CONVECTION A BIT, AND THE FORECAST IS FOR SCATTERED
CONVECTION OVER THE HIGHER TERRAIN AND ISOLATED CONVECTION
ELSEWHERE.
CENTRAL GUIDANCE REFLECTS A PERSISTENCE FORECAST FOR
TEMPERATURES AND DEW POINTS, WHICH SPELLS APPARENT TEMPERATURES
IN THE MID AND UPPER 90S THIS AND WEDNESDAY AFTERNOON, WITH 100
NOT OUT OF REACH FOR HOTTER URBAN AREAS.
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/
AS OF 239 PM TUESDAY...
THE UPPER LEVEL PATTERN BEGINS TO TRANSITION INTO A REX BLOCK
ORIENTATION WEDNESDAY NIGHT INTO THURSDAY WITH A MID LEVEL RIDGE
ACROSS THE NORTHEAST US AND A COASTAL LOW MOVING NORTHWARD ALONG THE
MID-ATLANTIC COASTAL AREAS. THIS PATTERN SHOULD SUPPORT A
CONTINUATION OF THE WARM AND HUMID CONDITIONS ACROSS OUR AREA WITH
TEMPERATURES AROUND TEN DEGREES ABOVE NORMAL. IN ADDITION, SCATTERED
CONVECTION WILL BE POSSIBLE ACROSS THE AREA DURING PEAK HEATING IN
THE AFTERNOON AND EVENING HOURS ON THURSDAY GIVEN THE WARM AND HUMID
AIRMASS IN PLACE. WITH LITTLE TO NO SHEAR AND A LACK OF UPPER
SUPPORT, ANY ACTIVITY IS EXPECTED TO BE PULSE CONVECTION WITH A MAIN
THREAT FOR LOCALLY HEAVY DOWNPOURS AS PWATS ARE EXPECTED TO EXCEED
1.75 INCHES. WHILE CONVECTIVE COVERAGE SHOULD BE SOMEWHAT LIMITED ON
THURSDAY DUE TO LACK OF FORCING, PRECIPITATION COVERAGE IS EXPECTED
TO INCREASE ON FRIDAY AS AN UPPER LEVEL TROUGH AND ASSOCIATED
FRONTAL BOUNDARY APPROACHES THE REGION. THUS, WILL LEAVE WIDESPREAD
HIGH CHANCE POPS IN THE FORECAST FOR NOW, BUT WOULDN'T BE SURPRISED
IF LIKELY POPS GETS INTRODUCED INTO SUBSEQUENT FORECASTS.
LONG TERM /SATURDAY THROUGH TUESDAY/
AS OF 239 PM TUESDAY...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE ONGOING ACROSS THE AREA
AT THE START OF THE LONG TERM PERIOD AS THE AFOREMENTIONED FRONTAL
BOUNDARY PUSHES THROUGH. PRECIPITATION COVERAGE SHOULD DECREASE BY
SATURDAY NIGHT AS THE UPPER TROUGH AND FRONTAL BOUNDARY PUSH EAST OF
THE AREA, BUT SHOWERS AND STORMS STILL APPEAR TO BE POSSIBLE ON
SUNDAY AS ADDITIONAL SHORTWAVE ENERGY MOVES INTO THE REGION. BY
EARLY NEXT WEEK, CONDITIONS ARE EXPECTED TO REMAIN UNSETTLED AS
MODELS SUGGEST THAT A CLOSED UPPER LOW MAY DEVELOP NEAR OR OVER THE
REGION MONDAY INTO TUESDAY. OTHERWISE, TEMPERATURES WILL BE
SLIGHTLY COOLER THIS WEEKEND FOLLOWING THE FRONTAL PASSAGE, BUT
STILL WILL REMAIN JUST ABOVE NORMAL THROUGH THE END OF THE LONG
TERM PERIOD.
AVIATION /19Z TUESDAY THROUGH SUNDAY/
AS OF 225 PM TUESDAY...
HEAT WAVE PATTERN CONTINUES, WITH DIURNALLY DRIVEN CONVECTION
AGAIN THIS AFTERNOON. CONVECTION WAS ALREADY FIRING IN SOUTHEAST
OHIO, AND SHOULD FIRE OVER THE HIGHER MOUNTAINOUS TERRAIN AS
WELL.
VALLEY FOG TONIGHT IS MOST LIKELY TO FORM IN AREAS THAT GET
RAIN THIS AFTERNOON OR EVENING. ANY FOG THAT DOES FORM IS
LIKELY TO BURN OFF BY OR SHORTLY AFTER 12Z WEDNESDAY, WITH
DIURNALLY DRIVEN CONVECTION ONCE AGAIN WEDNESDAY AFTERNOON.
SURFACE FLOW WILL REMAIN LIGHT AND VARIABLE. LIGHT SOUTHERLY
FLOW ALOFT BECOMES LIGHT AND VARIABLE AS WELL THIS AFTERNOON,
AND THEN LIGHT NORTHEAST ON WEDNESDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: AMENDMENTS MAY BE NEEDED FOR DIRECT
THUNDERSTORM IMPACTS THIS AFTERNOON OR EVENING. FOG FORMATION
MAY VARY OVERNIGHT, ESPECIALLY WHERE RAIN OCCURS.
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 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 18Z WEDNESDAY...
IFR POSSIBLE WITH VALLEY FOG IN THE LATE NIGHT/EARLY MORNING
HOURS EACH DAY EXCEPT AT BKW, ESPECIALLY IF RAIN FALLS AT THE
TERMINAL IN DAYTIME SHOWERS/STORMS. BRIEF IFR POSSIBLE IN
THUNDERSTORMS DURING THE AFTERNOON AND EVENING HOURS EACH DAY.
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON
INTO SATURDAY NIGHT, AND IN FOG OR STRATUS OVERNIGHT SATURDAY
NIGHT INTO SUNDAY MORNING.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
SYNOPSIS...TRM/RG
NEAR TERM...TRM
SHORT TERM...RG
LONG TERM...RG
AVIATION...TRM
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