612 FXUS61 KRLX 160218 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1017 PM EDT THU MAR 15 2012 .SYNOPSIS... UPPER LEVEL DISTURBANCES WITH SHOWERS TONIGHT INTO SUNDAY. HIGH PRESSURE EARLY NEXT WEEK WITH MILD TEMPERATURES. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 1015 PM UPDATE...LINE OF STORMS MOVING IN FROM THE WEST HAS WEAKENED AND NEARLY STALLED WHILE TRYING TO CROSS THE WV/KY BORDER. UPDATED TO INCLUDE SOME HIGHER POPS IN OUR EXTREME WESTERN AND SOUTHWESTERN ZONES TO ACCOUNT FOR THIS...BUT DID NOT CARRY VERY FAR INTO WV DUE TO LITTLE TO NO MOVEMENT. ALSO UPDATED TEMPS BASED ON CURRENT OBS. LOWERED LOWS IN MOUNTAINS A BIT DUE TO READINGS ALREADY AT OR BELOW FORECAST LOWS...AND RAISED THE THE TRI-STATE AREAS LOWS A COUPLE DEGREES DUE TO MORE CLOUDS. PREVIOUS DISCUSSION... PRIMARY FORECAST CONCERN FOR THE NEAR TERM CONTINUES TO BE CHANCES OF PERIODIC SHOWERS/THUNDERSTORMS ACROSS THE AREA AND SUBSEQUENT HYDRO CONCERNS. AS OF 18Z CURRENT BATCH OF SHOWERS AND THUNDERSTORMS PRIMARILY ACROSS SOUTHERN AND WESTERN PARTS OF THE FORECAST AREA SHOULD CONTINUE MOVING TO THE EAST/SOUTHEAST. STORMS MAY CONTINUE TO BE STRONG TO MARGINALLY SEVERE THROUGH ABOUT 21Z BEFORE WEAKER SHEAR MOVES OVER THE AREA. IN ITS WAKE ADDITIONAL DEVELOPMENT IS FORMING ACROSS WESTERN KENTUCKY ASSOCIATED WITH THE NEXT SHORTWAVE MOVING EAST/NORTHEAST THROUGH THE MEAN FLOW. IN SHORT...THERE SHOULD BE A BRIEF LULL IN PRECIP COVERAGE AND INTENSITY THIS EVENING AND POSSIBLY INTO THE EARLY OVERNIGHT HOURS BEFORE THE NEXT ROUND MAKES IN INTO THE AREA BETWEEN 06Z-09Z. WEAKER SHEAR OVERNIGHT WILL ALSO INCREASE WITH THE APPROACH OF THE SHORTWAVE TO AROUND 25KTS. MUCAPE ALSO INCREASES AS WELL BETWEEN 09Z-12Z WITH VALUES OF AROUND 500J-600J AS WELL. THOUGH SHEAR ISN/T IMPRESSIVE...ITS OBVIOUSLY CLOSE ENOUGH TO KEEP AN EYE ON WITH REGARD TO SEVERE POTENTIAL. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... LOOKING MORE LIKE A MAY OR JUNE TYPE PATTERN THAN A MID MARCH WEATHER PATTERN FOR THE MIDDLE OHIO VALLEY. LONG WAVE PATTERN HINTS AT RIDGING IN THE LOWER RESOLUTION PROGS...BUT EXAMINATION OF THE 12KM NAM CONTINUES TO DEPICT NUMEROUS SHORTWAVE TROUGHS EMBEDDED IN THE LARGE SCALE FLOW. SAME GOES WITH THE VORTICITY FIELDS. FOR FRIDAY...VERTICAL PROFILES EXHIBIT SIGNIFICANT INSTABILITY...AIDED BY DEWPOINTS APPROACHING 60F OVER THE WESTERN ZONES. WILL ALSO BE SATURATED THROUGH THE EQUILIBRIUM LEVEL...WITH MODEST CAPE...BUT EXISTING UPWARD THROUGH THE COLUMN PAST 300MB. PRECIPITABLE WATER VALUES WILL REMAIN BETWEEN 1.00 AND 1.25 INCHES...A RATHER HIGH WATER CONTENT GIVEN THE TIME OF YEAR. NOT HELPING MATTERS IS THE LACK OF VEGETATION TO ABSORB SOME OF THE RAINFALL...AND WITH THE GROUND SATURATED IN THE WESTERN HALF OF THE CWA FROM THE ACTION ONGOING TODAY...RUNOFF WILL CONTINUE TO BE A PROBLEM. MAY NEED TO LEAVE THE FLASH FLOOD WATCH FOR AN EXTENDED PERIOD OF TIME...BUT WILL LET THE EVENING SHIFT ULTIMATELY MAKE THAT DECISION. BOTTOM LINE...TOMORROW LOOKS A LOT LIKE TODAY IN TERMS OF THE SYNOPTIC SET UP...AND DO NOT HAVE ANY REASON TO THINK MULTIPLE ROUNDS OF THUNDERSTORMS WILL NOT OCCUR. INTO THE WEEKEND...CANNOT STABILIZE THE ATMOSPHERE...ALTHOUGH SATURDAY WILL HAVE SOME DRY AIR INTRUSION ABOVE 600MB. SO WHILE MORE SHOWERS AND STORMS ARE POSSIBLE...THE PRECIPITABLE WATER VALUES SHOULD COME DOWN A BIT. THE RIDGE ALOFT WILL BE CENTERED JUST TO THE EAST NORTHEAST INTO SOUTHERN PENNSYLVANIA AND THE DELMARVA...AND SHOULD EXERT A SMALL AMOUNT OF INFLUENCE KEEPING THE NORTHERN ZONES DRIER. LIKELY WILL NOT HAVE A FAR ENOUGH REACH TO AFFECT THE SOUTHERN AND WESTERN ZONES WHERE THE CHANCES FOR CONVECTION ARE BETTER. AS A RESULT...HAVE LOWER POPS OVERALL...WITH CHANCE IN THE SOUTHERN MOUNTAINS. SUNDAY...MAY SEE ANOTHER SLIGHT UPTICK IN OVERALL ACTIVITY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... UNSETTLED WEATHER TO CONTINUE IN THE LONG TERM...ESPECIALLY EARLY ON AS SEVERAL UPPER LEVEL DISTURBANCES CONTINUE TO MOVE THROUGH THE REGION. PLENTY OF MOISTURE WILL CONTINUE TO BE IN PLACE ACROSS THE AREA...WITH PW VALUES CONTINUING TO BE OVER AN INCH...OR ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. THIS MAY CONTINUE TO LEAD TO WATER ISSUES ACROSS THE CWA...AND WILL HAVE TO CONTINUE TO BE MONITORED. THERE MAY BE A BRIEF BREAK IN THE PRECIPITATION MID WEEK AS UPPER LEVEL RIDGING TRIES TO TAKE HOLD ACROSS THE EASTERN U.S....HOWEVER...ANY DRYING WILL BE SHORT LIVED AS BOTH GFS AND ECMWF ARE IN AGREEMENT OF A CUTOFF LOW FORMING TO OUR SOUTH AND WEST....THAT WILL CONTINUE TO PUSH MOISTURE NORTHWARD INTO OUR AREA TOWARDS THE END OF THE LONG TERM PERIOD. AS A RESULT...COULD SEE ANOTHER SOAKER OF A SITUATION...AND DEPENDING ON HOW THE WEEK SHAPES UP...POSSIBLE CONTINUED WATER PROBLEMS. ELECTED TO FOLLOW HPC THINKING IN THE LONG TERM...MAINLY KEEPING SLIGHT CHANCE POPS DUE TO UNCERTAINTY. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... KIND OF A MIXED BAG OF WEATHER GOING ON FOR THE TAF PERIOD. FIRST CONCERN IS STRONG THUNDERSTORMS MOVING IN FROM THE WEST...EXPECT THESE TO IMPACT KHTS BEFORE 02Z WITH THE POSSIBILITY OF GUSTY WINDS AND SMALL HAIL...WILL HANDLE THIS WITH A TEMPO. THESE STORMS SHOULD WEAKEN AS THEY MOVE EAST...SO LITTLE TO ANY IMPACT FROM THEM TO OTHER TAF SITES. NEXT CONCERN FOR TONIGHT IS DEVELOPMENT OF FOG. WITH A GOOD AMOUNT OF GROUND MOISTURE AVAILABLE FROM TODAYS RAIN...ANY BREAKS IN THE CLOUDS COULD GET THE FOG GOING. WITH THAT SAID...CLOUDS SHOULD BE INCREASING OVERNIGHT. LAV PROBABILITIES DO SHOW AT LEAST A CHANCE OF MVFR VISIBILITIES WITH FOG...SO TRIED TO TIME SOME MVFR FOG INTO TAFS BASED ON PRECIP AND SKY TRENDS. MORE SHOWERS ARE EXPECTED ON FRIDAY...BRINGING PERIODS OF MVFR. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: TIMING OF MVFR DUE TO SHOWERS AND FOG MAY DIFFER. COULD SEE DENSE FOG DEVELOP IN FOG PRONE AREAS TONIGHT IF CLOUDS DO NOT INCREASE. 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 FRI 03/16/12 UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09 CRW CONSISTENCY H H H H H H M L M M H H HTS CONSISTENCY H M M M M M M M H H H H BKW CONSISTENCY H H H H H H H M H H H H EKN CONSISTENCY H H H H H H M M M M H H PKB CONSISTENCY H H H H H L M L H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 00Z SATURDAY... FOG IS POSSIBLE EARLY SATURDAY MORNING...SOME OF IT COULD BE DENSE. MAY ALSO SEE BRIEF DROPS INTO IFR IN HEAVIER SHOWERS AND THUNDERSTORMS THROUGH SATURDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR WVZ005>010- 013>019-024>030-033>039. OH...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR OHZ066-067-075- 076-083>087. KY...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR KYZ101>103-105. VA...NONE. && $$ SYNOPSIS...MZ/50/SL/26 NEAR TERM...MZ/50 SHORT TERM...26 LONG TERM...SL AVIATION...MZ