Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 271300 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 900 AM EDT MON APR 27 2015 .SYNOPSIS... CHILLY NORTH FLOW TODAY WITH A MID/UPPER LEVEL DISTURBANCE PASSING LATE TODAY. DRY TUESDAY. MOISTURE CREEPS NORTH WEDNESDAY FROM WEAKENING SOUTHERN SYSTEM. NORTHERN TROF SWEEPS THROUGH THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... 9 AM UPDATE...TWEAKED SKY GRIDS. OTHERWISE...NO SIGNIFICANT CHANGES WERE NECESSARY. WITH FREEZING LEVELS AROUND 3500-4000 FEET...ANY SHOWER THIS AFTERNOON COULD HAVE SOME GRAUPEL WITH IT...ALONG WITH THE POSSIBILITY OF HIGHER ELEVATION SNOW SHOWERS. PREVIOUS DISCUSSION FOLLOWS... HAVE A COUPLE 500MB RIPPLES AND VORT MAXES TO FOCUS ON FOR THIS NEAR TERM PERIOD. THE FIRST IS EVIDENT BY CLOUDS IN OHIO AND EASTERN KENTUCKY. DO NOT EXPECT MUCH MORE THAN SOME CLOUDS WITH THIS ONE AS IT PASSES THIS MORNING DUE TO DRY AIR IN PLACE. THE SECOND FEATURE HAS SOME ASSOCIATED SHOWERS OVER LAKE HURON AND EASTERN MICHIGAN. EXPECT THIS FEATURE TO ROTATE ACROSS CWA THIS AFTERNOON AND EVENING. HAVE SHOWERS WITH THIS...WITH THE BEST CHANCE ACROSS THE NORTHEAST QUADRANT OF THE FORECAST AREA FROM 18Z TO 00Z. 850MB TEMPS ACROSS THE NORTHEAST WILL BE NEAR ZERO...AND EVEN DROPPING BELOW ZERO LATE THIS EVENING. BECAUSE OF THIS...HAVE SNOW SHOWERS ABOVE 3500 FT...WITH EVEN A DUSTING TO HALF INCH OF ACCUMULATION AT THE HIGHEST ELEVATIONS. TODAY WILL BE ANOTHER COOL DAY. MINIMAL CHANGES MADE TO THE FORECAST HIGHS. ALSO EXPECT A DECENT NORTHERLY BREEZE TODAY...WITH GUSTS OF 10-20 KTS ACROSS LOWER ELEVATIONS AND 20-30 KTS IN THE MOUNTAINS. SOMEWHAT UNCERTAIN HOW QUICKLY CLOUDS WILL SCATTER OUT TONIGHT...WHICH MAKES THE LOW TEMPERATURE DIFFICULT. ONLY MADE INSIGNIFICANT CHANGES TO PREVIOUS NUMBERS USING A CONSENSUS BLEND. THIS STILL KEEPS UP ON THE UPPER END OF THE FROST RANGE...SO HAVE SOME PATCHY FROST IN THE FORECAST. NOT CONFIDENT ENOUGH IN WIDESPREAD DAMAGING FROST TO ISSUE AN ADVISORY BUT WILL CONTINUE MENTION IN THE HWO. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... A STRANGE MID/UPPER LEVEL PATTERN AS MID/UPPER LOW LINGERS OFF NORTHEAST COAST. OVERALL...A RATHER WEAK LOW LEVEL FLOW IN OUR VICINITY. ANOTHER SOUTHERN MID LEVEL DISTURBANCE WEAKENS AS IT LIFTS TOWARD SOUTHERN COUNTIES ON WEDNESDAY. WILL NOT BE TOO EAGER MOVING CHANCE POPS INTO OUR NORTHERN COUNTIES...BUT DID INCREASE POPS TOWARD LKLY IN THE BKW VCNTY ON SOUTH INTO SW VIRGINIA WEDNESDAY AFTERNOON. THE ONLY SOLUTION I SAW THAT KEPT IT TOTALLY BONE DRY WAS THE CANADIAN. MEANWHILE...THE NOTABLE CHANGE FROM YESTERDAY IS THE NORTHERN STREAM DISTURBANCE DROPPING SOUTH FROM WESTERN ONTARIO ON WEDNESDAY. 00Z MODEL CONSENSUS IS TO DROP THIS DISTURBANCE A BIT FURTHER WEST INTO THE MID/UPPER OHIO VALLEY ON THURSDAY. AS A RESULT...HAD TO INCREASE POPS ON THURSDAY AND LINGER THE HIGHER POPS LONGER INTO THURSDAY EVENING. SEEMS TO BE THE APPROPRIATE WAY TO END THE WET MONTH OF APRIL. THOUGH WITH PRECIPITABLE WATER BELOW AN INCH...NO WATER CONCERNS WITH THESE SYSTEMS. EVEN LINGERED CHANCE POPS UNTIL FRIDAY MORNING OVER THE MOUNTAIN COUNTIES. NO MENTION OF THUNDER THROUGH THIS TIME FRAME. LOWERED MAXIMUM TEMPERATURE A BIT IN OUR SOUTH ON WEDNESDAY...BUT NOT A STRONG UPSLOPE FLOW THIS TIME AROUND. THINKING MAXIMUM TEMPERATURE ON WEDNESDAY MAY ACTUALLY BE WARMER NORTH OF CRW THAN SOUTH OF CRW...BASED ON LESS CLOUDS AND DRIER. ALSO STARTED TO LOWER MAXIMUM TEMPERATURE ON THURSDAY BASED ON INCREASE CHANCES OF SHOWERS. && .LONG TERM /FRIDAY THROUGH SUNDAY/... YET ANOTHER BATTLE BETWEEN THE NORTHERN AND SOUTHERN STREAMS EARLY IN THIS PERIOD...BEFORE THE NORTHERN STREAM TAKES OVER. THERE ARE MODEL DIFFERENCES IN HOW FAR NORTH A SOUTHERN STREAM UPPER LOW FROM THE SOUTHERN PLAINS STATES GETS INGESTED INTO THE AMPLIFYING NORTHERN STREAM UPPER TROUGH...WHICH DROPS DOWN THROUGH THE GREAT LAKES WEDNESDAY NIGHT AND THURSDAY. THE TREND IS FOR A MORE NORTHWARD TRACK OF THE SOUTHERN SYSTEM IN THE GFS AND EURO MODELS BEFORE GETTING KICKED OUT OFF THE CAROLINAS. THIS SCENARIO WILL BRING RAIN WITH LIKELY POPS TO THE SOUTHERN AND CENTRAL MOUNTAINS WEDNESDAY NIGHT AND THURSDAY...WITH POPS TAPERING OFF SLIGHT CHANCE OVER PARTS OF SOUTHEAST OHIO AND NORTHWESTERN WEST VIRGINIA...ALONG WITH COOLER THAN NORMAL TEMPERATURES. BY THURSDAY NIGHT...WITH THE SOUTHERN SYSTEM HAVING MOVED EAST OF THE AREA...WILL LEAVE JUST A LOW CHANCE FOR A BIT OF UPSLOPE RAIN SHOWERS IN THE NORTHERN MOUNTAINS AS CANADIAN HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. WILL NOT PUT ANY SNOW IN AT THIS POINT...BUT THIS CANNOT BE RULED OUT FOR THE HIGHEST ELEVATIONS. THEREAFTER...DRY NORTHWEST FLOW ALOFT AND SURFACE CANADIAN HIGH PRESSURE WILL BRING COOLER THAN NORMAL TEMPERATURES FRIDAY INTO THE WEEKEND...BUT NO EXTREMES. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... VFR IS EXPECTED THROUGH THIS MORNING. AN UPPER LEVEL WAVE WILL PASS THROUGH THIS AFTERNOON...WITH SOME RAIN SHOWERS POSSIBLE. MAINLY ACROSS THE NORTHEAST. ALSO HAVE SOME MVFR CIGS AT EKN AND BKW TONIGHT IN THE N TO NW FLOW BEHIND THIS FEATURE. NORTH WINDS WILL BECOME GUSTY THIS AFTERNOON...WITH GUSTS OF 15-25 KTS...BEFORE DECREASING AGAIN TONIGHT. THINK ENOUGH FLOW AND SOME CLOUDS WILL KEEP FOG AT BAY TONIGHT...ALTHOUGH SOME GUIDANCE DOES SUGGEST RIVER FOG FORMATION. WILL HAVE TO KEEP TRACK OF HOW QUICKLY CLOUDS SCATTER OUT OVERNIGHT. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: HIGH. ALTERNATE SCENARIOS: MAY GET BRIEF MVFR CIGS AT EKN EARLY THIS MORNING. MAY GET RIVER VALLEY FOG TONIGHT IF SKIES CLEAR. 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 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 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 M 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 TUESDAY... NO WIDESPREAD IFR CONDITIONS EXPECTED. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ/SL SHORT TERM...KTB LONG TERM...26 AVIATION...MZ

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