Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/05/12


AREA FORECAST DISCUSSION
NWS PUEBLO CO
1104 PM MDT THU AUG 2 2012 .AVIATION... VFR CONDITIONS EXPECTED AT ALL 3 TAF SITES...KCOS...KPUB AND KALS NEXT 24H. THERE WILL BE A SLIGHT CHANCE OF THUNDER DURING THE LATE AFTERNOON/EARLY EVENING BUT PROBABILITY TOO LOW TO MENTION EXPLICITLY IN TAF PRODUCTS ATTM. && .PREV DISCUSSION... /ISSUED 328 PM MDT THU AUG 2 2012/ SHORT TERM... (TONIGHT AND FRIDAY) THE MONSOON MOISTURE PLUME REMAINS OVER THE AREA WITH SHOWERS AND THUNDERSTORMS OVER AND NEAR THE MOUNTAINS EARLY THIS AFTERNOON. THE MODELS ARE SHOWING THE CONVECTIVE ACTIVITY SPREADING ACRS THE PLAINS LATE THIS AFTERNOON THROUGH THE EVENING HOURS...IN ASSOCIATION WITH A WEAK DISTURBANCE WORKING ITS WAY EAST ACRS SOUTHERN CO. THE HRRR SHOWS A BAND OF PCPN COMING OFF THE MTS BY 00Z...MOVING EASTWARD ACRS THE PLAINS AND EXITING CO BY 04Z. THE NSSL 4KM WRF IS VERY SIMILAR. BASED ON THESE HIGH RES MODELS WL GO AHEAD AND END PCPN CHANCES IN THE FORECAST BY MIDNIGHT...HOWEVER BOTH THE NAM AND GFS KEEP CHANCES FOR PCPN OVR THE FAR SERN PLAINS THROUGH THE NIGHT AND INTO FRI MORNING. THERE IS THE POTENTIAL FOR HEAVY RAIN TODAY UNDER SOME OF THE STRONGER STORMS...WITH THE WALDO CANYON BURN SCARS BEING THE MOST VULNERABLE IF HEAVY RAIN DEVELOPS OVR THAT AREA. ON FRI THE BULK OF THE MONSOON MOISTURE WILL BE OVR SOUTHERN PORTIONS OF THE FORECAST AREA...AS AN UPR TROF OVR THE NRN ROCKIES FLATTENS THE RIDGE OVR OUR AREA. THUS THE BEST CHANCES FOR CONVECTIVE ACTIVITY SHOULD OCCUR OVR THE SRN HALF OF THE CWA. THE GFS HAS LITTLE IN THE WAY OF PCPN COVERAGE FOR FRI AFTERNOON...WHILE THE NAM HAS A LITTLE MORE COVERAGE OVER THE FAR SOUTHEAST PLAINS...THE SANGRES AND THE EASTERN SAN JUANS. HIGH TEMPS ON FRIDAY SHOULD BE A FEW DEGREES ABOVE NORMAL IN MOST LOCATIONS. LONG TERM... (FRIDAY NIGHT THROUGH THURSDAY) LONGER TERM METEOROLOGICAL ISSUES CONTINUE TO BE POPS AND TEMPERATURES. LATEST COMPUTER SOLUTIONS INDICATE THAT STRONG UPPER RIDGE CENTERED OVER NORTHWESTERN TEXAS AT 00Z SATURDAY WILL BEGIN TO PUSH WEST INTO NEW MEXICO BY LATER SUNDAY BEFORE BECOMING CENTERED NEAR THE 4-CORNERS REGION BY NEXT TUESDAY. IN ADDITION...HEALTHY NORTHERLY SURGE IS PROJECTED TO PUSH ACROSS EASTERN SECTIONS OF THE FORECAST DISTRICT BY SATURDAY MORNING. ENOUGH ATMOSPHERIC MOISTURE IS EXPECTED TO REMAIN AVAILABLE OVER THE FORECAST DISTRICT AND COMBINE WITH OCCASIONAL UPPER WAVES AND THE DAILY HEATING CYCLE/SURFACE BOUNDARIES TO ALLOW DAILY ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM ACTIVITY...ESPECIALLY OVER THE HIGHER TERRAIN REGIONS. SOME OF THE STRONGER THUNDERSTORMS ARE EXPECTED TO PRODUCE PERIODS OF LOCALLY HEAVY RAINFALL CAPABLE OF PRODUCING LOCALIZED FLASH FLOODING ISSUES...ESPECIALLY IF A STORM DIRECTLY IMPACTS BURN SCAR AREAS...SUCH AS THE WALDO BURN SCAR. IN ADDITION...THE STRONGER STORMS WILL ALSO BE CAPABLE OF PRODUCING HAZARDOUS LIGHTNING...HAIL AND GUSTY WINDS. FINALLY...BELOW SEASONAL MAXIMUM TEMPERATURES SHOULD BE NOTED IN THE WAKE OF THE STRONG NORTHERLY SURGE SATURDAY(ESPECIALLY EASTERN SECTIONS) WITH MAXIMUM TEMPERATURES THEN REBOUNDING TO ABOVE EARLY AUGUST SEASONAL AVERAGES NEXT WEEK. AVIATION... KALS...KCOS AND KPUB WILL HAVE VFR CONDITIONS MOST OF THE TIME DURING THE NEXT 24 HRS. THERE WILL BE A CHANCE FOR SHOWERS AND THUNDERSTORMS AT OR IN THE VCNTY OF THE TAF SITES THROUGH AROUND 03Z. THUNDERSTORMS COULD BRING BRIEF MVFR CONDITIONS TO THE TAF SITES. OUTFLOW WINDS COULD ALSO BRING WIND GUSTS UP TO 45 KTS. ON FRIDAY AFTERNOON WE COULD SEE SOME THUNDERSTORMS IN THE VCNTY OF THE TAF SITES AFTER 20Z...BUT CONFIDENCE IS LOW. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 34/34
AREA FORECAST DISCUSSION
NWS NEW YORK NY
158 PM EDT FRI AUG 3 2012 .SYNOPSIS... HIGH PRESSURE WILL MAINLY INFLUENCE THE WEATHER ACROSS THE TRI-STATE REGION THROUGH SATURDAY AS THE BERMUDA HIGH STRENGTHENS OFF THE EASTERN SEABOARD. A COLD FRONT WILL SLOWLY WORK ITS WAY ACROSS THE REGION SUNDAY THROUGH MONDAY. HIGH PRESSURE RETURNS ON TUESDAY...THEN A SERIES OF FRONTAL BOUNDARIES WILL IMPACT THE AREA FOR THE MIDDLE OF THE NEW WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WARM TO HOT TEMPS...HIGH DEW POINTS IN THE 70S HAVE RESULTED IN SFC BASED CAPES AROUND 3K TO 4K J/KG ACROSS LONG ISLAND. ISOLATED SHOWERS AND TSTMS COULD CONTINUE TO FORM ON THE SEA BREEZE BOUNDARY...AND THE MAIN FORMATION SHOULD BE ACROSS THE INTERIOR AS THE AFTERNOON PROGRESSES. THE OTHER TRIGGER WILL BE DIFFERENTIAL HEATING DRIVEN BY THE HILLS NORTH AND WEST OF NYC. A MODERATELY UNSTABLE...WEAKLY SHEARED ENVIRONMENT COULD PRODUCE A FEW PULSE STORMS. WARMING HEIGHTS ALOFT AND AN ONSHORE FLOW WILL PRODUCE HOT AND HUMID CONDITIONS ACROSS THE FORECAST AREA. HEAT INDEX VALUES ALREADY AROUND 95 FOR NYC...BUT THERE IS ONLY LOW CONFIDENCE FOR THE TWO CONSECUTIVE DAYS NEEDED TO ISSUE A HEAT ADVISORY. THIS BEING AUGUST AND WITH SEVERAL HEAT WAVES UNDER OUR BELT...PREFERRED TO HOLD OFF AT THIS TIME WITH ONLY MARGINAL VALUES. TEMPS RANGING FROM THE MID TO UPPER 80S AT THE COAST...TO 90 TO 95 NYC METRO AND THE INTERIOR. THERE IS MODERATE RISK OF RIP CURRENTS TODAY AT THE OCEAN BEACHES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... WARM...MUGGY CONDITIONS WILL CONTINUE TONIGHT INTO SATURDAY WITH A NEAR CARBON COPY OF TODAY. THE FLOW LOOKS TO BE MORE S/SE WHICH SHOULD ALLOW FOR MORE OF A MARINE INFLUENCE INLAND. THIS WILL ALLOW FOR SLIGHTLY COOLER HIGHS ON SAT...BUT HIGHER DEW POINTS... RESULTING IN PRETTY MUCH A WASH. 594 DM HEIGHTS ASSOC WITH THE SUB TROP HIGH OFF THE EAST COAST BUILD WESTWARD ON SAT. THUS...ANOTHER WARM DAY ALOFT...WHICH SHOULD PRETTY MUCH PUT A LID ON ANY WIDESPREAD CONVECTION. SHOULD BE SIMILAR TO FRIDAY WITH JUST A SLIGHT CHC ACROSS THE INTERIOR. ONCE AGAIN USED A BLEND OF MET/MAV MOS. TEMPS ARE ABOUT 4 TO 8 DEGREES ABOVE NORMAL WITH RESPECT TO BOTH HIGHS AND LOWS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THE REGION WILL BE IN A SUB-TROPICAL REGIME THROUGH MUCH OF THE PERIOD WITH PERSISTENT WESTERN ATLANTIC RIDGING AND HUDSONS BAY TROUGHING. A SHARP NORTHERN STREAM SHORTWAVE WILL TRACK THROUGH THE GREAT LAKES ON SATURDAY NIGHT INTO SUNDAY...AND THEN WEAKEN AS IT LIFTS THROUGH NEW ENGLAND SUN NIGHT INTO MONDAY. AT THE SURFACE...A COLD FRONT WILL TRACK EAST THROUGH THE GREAT LAKES ON SAT NIGHT INTO SUNDAY...WITH AN ASSOCIATED WARM FRONT LIFTING THROUGH THE REGION SUNDAY MORNING AND PRE-FRONTAL TROUGH APPROACHING LATE SUNDAY. THE COLD FRONT ITSELF CROSSES THROUGH THE REGION ON MONDAY. ANY CONVECTION SHOULD GRADUALLY DISSIPATE SATURDAY EVENING WITH WANING INSTABILITY. OTHERWISE...ISOLATED SHRA/TSRA POTENTIAL OVERNIGHT WITH MODELS HINTING AT LEAD SHORTWAVE ENERGY LIFTING THROUGH AND MARGINAL INSTABILITY. A FEW SHOWERS/ISOLATED TSTMS POSSIBLE WITH THE WARM FRONTAL PASSAGE SUNDAY MORNING AS LLJ BEGINS TO STRENGTHEN. INCREASING CHANCE OF THUNDERSTORMS LATE SUNDAY INTO SUNDAY NIGHT WITH FALLING HEIGHTS AHEAD OF THE APPROACHING SHORTWAVE TROUGH AND APPROACHING PRE-FRONTAL TROUGH. UNCERTAINTY EXISTS ON COVERAGE OF STORMS ON SUNDAY AFTERNOON/EARLY SUNDAY EVENING...AS IT DEPENDS ON HOW FAR EAST THE PRE-FRONTAL TROUGH MAKES IT DURING THE AFTERNOON/EARLY EVENING. IF THE PRE- FRONTAL TROUGH CAN WORK INTO WESTERN PORTIONS OF THE REGION BY LATE IN THE DAY...THIS COULD ACT AS A FOCUS FOR AN ORGANIZED LINE OF STRONG TO SEVERE CONVECTION WITH A DAMAGING WIND THREAT. IF THE PRE-FRONTAL TROUGH REMAIN WEST OF THE AREA...CONVECTION WILL LIKELY BE MORE SCATTERED AND FOCUSED ALONG SEABREEZE BOUNDARIES...HIGHER ELEVATIONS AND OUTFLOW BOUNDARIES IN A LOW CIN ENVIRONMENT. IN THIS CASE...A FEW STRONG TO SEVERE STORMS ARE POSSIBLE WITH MODERATE TO HIGH INSTABILITY AND INCREASING LOW LEVEL WINDS/SHEAR. OVERRIDING THREAT WITH ANY STORMS WILL LIKELY BE TORRENTIAL DOWNPOURS AND POTENTIAL FOR LOCALIZED FLASH FLOODING WITH BACK BUILDING BASED ON THE LOW/MID LEVELS WINDS. INCREASING POTENTIAL FOR HEAVY SHOWERS/THUNDERSTORMS SUNDAY NIGHT CONTINUING INTO MONDAY MORNING WITH SHORTWAVE APPROACH AND PRE-FRONTAL TROUGH/COLD FRONT ENTERING AND CROSSING THE REGION. SEVERE THREAT WILL DIMINISH SUNDAY EVENING...BUT STRONG STORMS POSSIBLE DUE TO STRONG LOW-LEVEL WINDS. MAIN THREAT THOUGH SHOULD BE FLOODING SUNDAY NIGHT INTO MONDAY MORNING WITH PWATS INCREASING TO 2.25 TO 2.5 INCHES AND TRAINING POTENTIAL AS LO/MID LEVEL WINDS NEARLY ALIGN WITH THE FRONT. COLD FRONT PUSHES THROUGH THE REGION THROUGH MONDAY MORNING/AFTERNOON...WITH SHOWER/TSTM THREAT TAPERING FROM W TO E. GRADUAL DRYING CONDITIONS EXPECTED IN THE WAKE OF THE FRONT MON AFTERNOON/NIGHT. HIGH PRES OVER THE AREA WILL RESULT IN A PLEASANT DAY ON TUESDAY...WITH PARTLY CLOUDY SKIES...LIGHT NORTH WINDS TURNING SOUTH WITH AFTERNOON SEA BREEZES...AND TEMPS TOPPING OFF IN THE MID 80S. UNSETTLED WEATHER RETURNS ON WEDNESDAY AS STATIONARY FRONT SOUTH OF THE REGION LIFTS BACK NORTH AS A WARM FRONT...THEN A COLD FRONT SWINGS THROUGH ON THURSDAY. TEMPS WILL BE NEAR TO SLIGHTLY ABOVE NORMAL DURING THE PERIOD. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... A WEAK PRESSURE PATTERN WILL REMAIN OVER THE REGION THROUGH THE TAF PERIOD WITH MAINLY VFR EXPECTED. THE ONLY EXCEPTION WILL BE SOME EARLY MORNING MVFR OR IFR FOG. ANY SUB-VFR CIGS ARE EXPECTED TO IMPROVE TO VFR BY 13Z-15Z. AN ISOLATED THUNDERSTORM IS POSSIBLE AT ANY TIME FROM THIS AFTERNOON INTO THE EARLY EVENING. ANY ADDITIONAL DEVELOPMENT WOULD LIKELY BE ALONG THE SEA BREEZE CONVERGENCE OVER LONG ISLAND OR ACROSS THE LOWER HUDSON VALLEY. HRRR KEEPS LOOKING TO BRING SOME ACTIVITY ACROSS THE LOWER HUDSON VALLEY AND WESTERN NJ ACROSS NYC LATER THIS AFTERNOON HOWEVER STILL NOT CONFIDENT ENOUGH CONFIDENCE TO INCLUDE ANY ACTIVITY IN THE TAFS. CIRRUS STREAKING EASTWARD ACROSS PA ATTM MAY ALSO HELP TO INHIBIT ADDITIONAL CU DEVELOPMENT IN THE IMMEDIATE VICINTY OF THE TERMINALS. WINDS ARE GENERALLY SW UNDER 10 KT THROUGH THE PERIOD. DURING THE AFTERNOON...SEA BREEZES ARE EXPECTED TO SHIFT WINDS MORE SOUTHERLY AND INCREASE SLIGHTLY. WINDS WILL BECOME LIGHT AND VARIABLE ONCE AGAIN TONIGHT. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: FORECAST ON TRACK. NO UNSCHEDULED AMENDMENTS ANTICIPATED. KLGA FCSTER COMMENTS: FORECAST ON TRACK. NO UNSCHEDULED AMENDMENTS ANTICIPATED. KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEABREEZE WIND SHIFTS. KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEABREEZE WIND SHIFTS. KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEABREEZE WIND SHIFTS. KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEABREEZE WIND SHIFTS. ALSO NEARBY ISOLATED SHOWERS MAY REQUIRE AMENDMENTS IF THEY PASS NEAR THE AIRPORT. OUTLOOK FOR 18Z SAT THROUGH WED... .SAT...CHC VSBYS BELOW 6SM IN BR EARLY AM...ESPECIALLY OUTLYING TERMINALS. ISOLD/SCT TSTMS POSSIBLE LATE AFTN/EVE. .SUN...GUSTY S WINDS....MAINLY IN THE AFTERNOON. LATE DAY TSTMS POSSIBLE WITH AN APPROACHING COLD FRONT. .MON...MORNING SUB-VFR POSSIBLE IN TSRA/SHRA...THEN IMPROVING. .TUE/WED...VFR. && .MARINE... SOUTHERLY FLOW TO AROUND 10 KT CONTINUES INTO SATURDAY AS HIGH PRESSURE REMAINS OVER THE ATLANTIC. SUB SCA CONDITIONS ARE EXPECTED...WITH LOCAL ENHANCEMENT TO WINDS DURING THE AFTERNOON AND EVENING DUE TO SEA BREEZES. SUB-SCA CONDS CONTINUE SATURDAY NIGHT INTO SUNDAY MORNING...THEN THE SOUTHERLY PRES GRADIENT INCREASES LATE SUNDAY THROUGH MONDAY MORNING...RESULTING IN 25 KT WIND GUSTS...MAINLY ON THE OCEAN WATERS...AND OCEAN SEAS BUILDING TO 5-7 FT. WINDS ARE EXPECTED TO DIMINISH FROM W TO E MONDAY MORNING...BUT OCEAN SEAS WILL LIKELY TAKES UNTIL MONDAY NIGHT TO FALL BELOW SCA LEVELS. COLD FRONT MOVES THROUGH THE WATERS SUNDAY NIGHT. THUNDERSTORMS WILL BE CAPABLE OF HEAVY RAIN...RESULTING IN DIMINISHED VSBYS...AND THUNDERSTORM WIND GUSTS EXCEEDING 34 KT. SUB-SCA CONDS THEN EXPECTED MONDAY NIGHT THROUGH THE MIDDLE OF THE WEEK. && .HYDROLOGY... ISOLATED THUNDERSTORMS DURING THE DAYTIME COULD RESULT IN LOCAL NUISANCE URBAN/POOR DRAINAGE FLOODING TODAY AND SATURDAY. PRIMARY AREA OF CONCERN IS TO THE NORTH AND WEST OF NYC. THUNDERSTORMS WILL BE CAPABLE OF TORRENTIAL RAINS SUNDAY AFTERNOON INTO MONDAY MORNING. URBAN AND POOR DRAINAGE FLOODING WILL BE A THREAT WITH ANY CONVECTION...WITH A THREAT FOR FLASH FLOODING FROM BACK BUILDING OR TRAINING STORMS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...NV/DW NEAR TERM...DW/PW SHORT TERM...DW LONG TERM...NV AVIATION...IRD MARINE...NV/DW/PW HYDROLOGY...NV/DW
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
927 PM EDT SAT AUG 4 2012 .UPDATE 2... SHOWERS AND THUNDERSTORMS HAVE ENDED OVER THE LAND AREAS OF SOUTH FLORIDA THIS EVENING...AS SHOWERS AND THUNDERSTORMS WERE DEVELOPING OVER THE ATLANTIC AND GULF WATERS. THE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER BOTH THE ATLANTIC AND GULF WATERS TONIGHT...AS A TROUGH OF LOW PRESSURE WILL REMAIN NEARLY STATIONARY OVER SOUTH FLORIDA. HOWEVER...THE LAND AREAS OF SOUTH FLORIDA SHOULD REMAIN DRY TONIGHT DUE TO THE STABLE CONDITIONS. SO WILL REMOVE THE POPS OVER OVER THE LAND AREAS OF SOUTH FLORIDA TONIGHT...EXCEPT FOR THE EAST COAST METRO AREAS WHERE THE POPS WILL REMAIN AROUND 20 PERCENT WHERE A FEW SHOWERS AND THUNDERSTORMS COULD WORK INTO THIS AREA FROM THE ATLANTIC WATERS. THE GULF AND ATLANTIC WATERS WILL CONTINUE TO SEE 20 TO 30 PERCENT POPS TONIGHT. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES AREA PLANNED FOR THE EVENING UPDATE. && .UPDATE 2...54/BNB .PREV DISCUSSION... /ISSUED 752 PM EDT SAT AUG 4 2012/ AVIATION... FOR THE SHORT TERM...TERMINAL KAPF HAS VCTS WITH BRIEF PERIODS OF SUB-VFR CONDITIONS POSSIBLE OVER THE NEXT HOUR OR SO WITH OCCURRENCE OF SHOWERS OR A THUNDERSTORM. FOR THE EAST COAST TERMINALS...THERE ARE LINGERING SHOWERS IN VICINITY OF TERMINALS KFLL...KOPF...KMIA AND KTMB WITH MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALTHOUGH A BRIEF SHOWER IS POSSIBLE OVER THE NEXT HOUR OR SO. THERE ARE LINGERING BOUNDARIES ACROSS THE PENINSULA WHICH COULD START NEW CONVECTION...BUT MAINLY EXPECT CONVECTION TO START SUBSIDING WITH MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS AFTER 02Z. && 60 PREV DISCUSSION... /ISSUED 741 PM EDT SAT AUG 4 2012/ UPDATE... THE SHOWERS AND THUNDERSTORMS HAVE SHIFTED INTO THE WESTERN AREAS OF SOUTH FLORIDA EARLY THIS EVENING WHERE BEST INSTABILITY IS LOCATED. SO HAVE INCREASED THE POPS FOR THE WESTERN AREAS...AND REDUCED THE POPS OVER THE EASTERN AREAS OF THE CWA FOR REST OF THE EVENING HOURS. && UPDATE...54/BNB PREV DISCUSSION... /ISSUED 154 PM EDT SAT AUG 4 2012/ SHORT TERM...(TONIGHT-MONDAY NIGHT) THE LATEST SURFACE ANALYSIS SHOWED A TROUGH EXTENDING SOUTH OF A WEAK LOW PRESSURE AREA CENTERED ALONG IT NORTHWEST OF THE BAHAMAS OR EAST SOUTHEAST OF FT PIERCE. LIGHT WNW FLOW ACROSS THE LOCAL AREA TO ITS SOUTHWEST COMBINED WITH THE ATLANTIC SEA BREEZE HAS ALREADY LED TO A FEW SHOWERS DEVELOPING ALONG IT OVER PALM BEACH COUNTY NEAR THE COAST AND FARTHER SOUTH ALONG THE EAST COAST AREAS. LOCAL WRF AND HRRR MODEL REFLECTIVITIES SEEM TO BE INITIALIZING WELL WITH THIS PATTERN AND GENERALLY INDICATE THIS ACTIVITY INCREASING IN COVERAGE THROUGH THE COURSE OF THE AFTERNOON TODAY AS THE ATL SEA BREEZE CONTINUES TO MAKE ITS PUSH INLAND. THIS COMBINED WITH THE ACTIVITY FROM YESTERDAY COULD GENERATE MORE FLOODING CONCERNS DEPENDING ON WHERE THE HEAVIEST ACTIVITY BECOMES CONCENTRATED AS THE DAY PROGRESSES. THE MORNING UPPER AIR SOUNDING AT MIAMI ALONG WITH THE LATEST SATELLITE DERIVED 500 MB TEMPERATURES INDICATE A MORE STABLE ENVIRONMENT COMPARED TO YESTERDAY AND WITH THE BEST INSTABILITY OR COOLER MID /UPPER-LEVEL AIR NOW TO THE WEST OF THE FL PENINSULA CLOSER TO THE BROAD UPPER LOW CENTER OVER THE GULF OF MEXICO. THEREFORE...THE MAIN IMPACTS FROM ANY STRONG STORMS THAT DO DEVELOP SHOULD REMAIN SUB-SEVERE AND MAINLY ASSOCIATED WITH STRONG WIND GUSTS UP TO 50 MPH. THE LATEST NUMERICAL MODEL GUIDANCE HAS INITIALIZED WELL WITH THIS SURFACE TROUGH AND LOW JUST EAST OF THE LOCAL AREA AND GENERALLY INDICATES THIS FEATURE CONTINUING WESTWARD OVER SOUTH FLORIDA THROUGH TONIGHT...THEN WEST OF THE FL PENINSULA SUNDAY THROUGH MONDAY. IN ITS WAKE...MOIST SOUTHEAST FLOW WILL BE EXPECTED AS THE AFOREMENTIONED SURFACE TROUGH/UPPER LOW CONTINUES WEST AND AWAY FROM THE FL PENINSULA AND ERNESTO CONTINUES ITS WESTWARD TRACK ACROSS THE CARIBBEAN SEA AND PASSES THE LOCAL AREA TO THE SOUTH SUNDAY THROUGH MONDAY NIGHT. MODERATE EAST AND SOUTHEAST FLOW THROUGH THE LOW LEVELS DUE TO A SLIGHTLY ENHANCED GRADIENT BETWEEN ERNESTO TO THE SOUTH AND THE SUBTROPICAL RIDGE TO THE NORTH COMBINED WITH PRECIPITABLE WATER VALUES AROUND THE TWO INCH MARK WILL KEEP THE RAIN CHANCES IN THE FORECAST THROUGH THE PERIOD. LONG TERM (TUESDAY-FRIDAY)... ATLANTIC HIGH PRESSURE WILL BUILD INTO SOUTH FL BEGINNING TUE AND LASTING THROUGH THE WORK WEEK WITH DRIER AIR MOVING IN FROM THE EAST. PWATS LOWER TO AROUND 1.5 INCHES WED-THU...WITH EVEN A LITTLE BIT OF HAZE FROM SAHARAN DUST POSSIBLY MOVING IN MID WEEK. WITH THE EASTERLY FLOW IN PLACE...SHOWERS/TSTMS THAT DEVELOP DURING THIS TIME SHOULD HAVE THE BEST CHANCE OF FORMING OVER THE INLAND AND WESTERN LOCATIONS EACH AFTERNOON. MOISTURE BEGINS TO INCREASE ACROSS THE AREA BY FRI. MARINE... A TROUGH EXTENDING SOUTH OF A WEAK LOW PRESSURE AREA CENTERED NORTH OF THE BAHAMAS OR EAST SOUTHEAST OF CAPE CANAVERAL IS FORECAST TO TRACK WEST AND NORTHWEST ACROSS THE FLORIDA PENINSULA THROUGH TONIGHT. SCATTERED SHOWER AND STORMS ASSOCIATED WITH THIS FEATURE WILL LEAD TO PERIODS WITH REDUCED VISIBILITIES ALONG WITH LOCALLY HIGHER WINDS AND SEAS...ESPECIALLY ACROSS THE ATLANTIC WATERS. SUNDAY THROUGH THE MID WEEK PERIOD...MODERATE EASTERLY WINDS AND SEAS WILL BE ANTICIPATED AS TROPICAL STORM ERNESTO PASSES SOUTH OF THE MARINE AREA ACROSS THE CARIBBEAN SEA. FOR THE LATEST INFORMATION REGARDING ERNESTO...REFER TO THE LATEST FORECASTS AND ADVISORIES ISSUED BY THE NATIONAL HURRICANE CENTER. FIRE WEATHER... NO CONCERNS THROUGH THE WEEKEND AND INTO THE UPCOMING WEEK AS PLENTY OF MOISTURE AND RAIN CHANCES REMAIN IN THE FORECAST.SOME DRIER AIR WITH MODERATE EASTERLY FLOW APPEARS POSSIBLE THROUGH THE MID-WEEK PERIOD. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 88 79 88 / 20 60 40 60 FORT LAUDERDALE 79 90 80 89 / 20 60 40 60 MIAMI 78 89 79 89 / 20 60 40 60 NAPLES 76 92 76 90 / 50 50 40 60 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS MIAMI FL
752 PM EDT SAT AUG 4 2012 .AVIATION... FOR THE SHORT TERM...TERMINAL KAPF HAS VCTS WITH BRIEF PERIODS OF SUB-VFR CONDITIONS POSSIBLE OVER THE NEXT HOUR OR SO WITH OCCURRENCE OF SHOWERS OR A THUNDERSTORM. FOR THE EAST COAST TERMINALS...THERE ARE LINGERING SHOWERS IN VICINITY OF TERMINALS KFLL...KOPF...KMIA AND KTMB WITH MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALTHOUGH A BRIEF SHOWER IS POSSIBLE OVER THE NEXT HOUR OR SO. THERE ARE LINGERING BOUNDARIES ACROSS THE PENINSULA WHICH COULD START NEW CONVECTION...BUT MAINLY EXPECT CONVECTION TO START SUBSIDING WITH MAINLY VFR CONDITIONS EXPECTED TO PREVAIL ALL TERMINALS AFTER 02Z. 60 && .PREV DISCUSSION... /ISSUED 741 PM EDT SAT AUG 4 2012/ UPDATE... THE SHOWERS AND THUNDERSTORMS HAVE SHIFTED INTO THE WESTERN AREAS OF SOUTH FLORIDA EARLY THIS EVENING WHERE BEST INSTABILITY IS LOCATED. SO HAVE INCREASED THE POPS FOR THE WESTERN AREAS...AND REDUCED THE POPS OVER THE EASTERN AREAS OF THE CWA FOR REST OF THE EVENING HOURS. UPDATE...54/BNB PREV DISCUSSION... /ISSUED 154 PM EDT SAT AUG 4 2012/ SHORT TERM...(TONIGHT-MONDAY NIGHT) THE LATEST SURFACE ANALYSIS SHOWED A TROUGH EXTENDING SOUTH OF A WEAK LOW PRESSURE AREA CENTERED ALONG IT NORTHWEST OF THE BAHAMAS OR EAST SOUTHEAST OF FT PIERCE. LIGHT WNW FLOW ACROSS THE LOCAL AREA TO ITS SOUTHWEST COMBINED WITH THE ATLANTIC SEA BREEZE HAS ALREADY LED TO A FEW SHOWERS DEVELOPING ALONG IT OVER PALM BEACH COUNTY NEAR THE COAST AND FARTHER SOUTH ALONG THE EAST COAST AREAS. LOCAL WRF AND HRRR MODEL REFLECTIVITIES SEEM TO BE INITIALIZING WELL WITH THIS PATTERN AND GENERALLY INDICATE THIS ACTIVITY INCREASING IN COVERAGE THROUGH THE COURSE OF THE AFTERNOON TODAY AS THE ATL SEA BREEZE CONTINUES TO MAKE ITS PUSH INLAND. THIS COMBINED WITH THE ACTIVITY FROM YESTERDAY COULD GENERATE MORE FLOODING CONCERNS DEPENDING ON WHERE THE HEAVIEST ACTIVITY BECOMES CONCENTRATED AS THE DAY PROGRESSES. THE MORNING UPPER AIR SOUNDING AT MIAMI ALONG WITH THE LATEST SATELLITE DERIVED 500 MB TEMPERATURES INDICATE A MORE STABLE ENVIRONMENT COMPARED TO YESTERDAY AND WITH THE BEST INSTABILITY OR COOLER MID /UPPER-LEVEL AIR NOW TO THE WEST OF THE FL PENINSULA CLOSER TO THE BROAD UPPER LOW CENTER OVER THE GULF OF MEXICO. THEREFORE...THE MAIN IMPACTS FROM ANY STRONG STORMS THAT DO DEVELOP SHOULD REMAIN SUB-SEVERE AND MAINLY ASSOCIATED WITH STRONG WIND GUSTS UP TO 50 MPH. THE LATEST NUMERICAL MODEL GUIDANCE HAS INITIALIZED WELL WITH THIS SURFACE TROUGH AND LOW JUST EAST OF THE LOCAL AREA AND GENERALLY INDICATES THIS FEATURE CONTINUING WESTWARD OVER SOUTH FLORIDA THROUGH TONIGHT...THEN WEST OF THE FL PENINSULA SUNDAY THROUGH MONDAY. IN ITS WAKE...MOIST SOUTHEAST FLOW WILL BE EXPECTED AS THE AFOREMENTIONED SURFACE TROUGH/UPPER LOW CONTINUES WEST AND AWAY FROM THE FL PENINSULA AND ERNESTO CONTINUES ITS WESTWARD TRACK ACROSS THE CARIBBEAN SEA AND PASSES THE LOCAL AREA TO THE SOUTH SUNDAY THROUGH MONDAY NIGHT. MODERATE EAST AND SOUTHEAST FLOW THROUGH THE LOW LEVELS DUE TO A SLIGHTLY ENHANCED GRADIENT BETWEEN ERNESTO TO THE SOUTH AND THE SUBTROPICAL RIDGE TO THE NORTH COMBINED WITH PRECIPITABLE WATER VALUES AROUND THE TWO INCH MARK WILL KEEP THE RAIN CHANCES IN THE FORECAST THROUGH THE PERIOD. LONG TERM (TUESDAY-FRIDAY)... ATLANTIC HIGH PRESSURE WILL BUILD INTO SOUTH FL BEGINNING TUE AND LASTING THROUGH THE WORK WEEK WITH DRIER AIR MOVING IN FROM THE EAST. PWATS LOWER TO AROUND 1.5 INCHES WED-THU...WITH EVEN A LITTLE BIT OF HAZE FROM SAHARAN DUST POSSIBLY MOVING IN MID WEEK. WITH THE EASTERLY FLOW IN PLACE...SHOWERS/TSTMS THAT DEVELOP DURING THIS TIME SHOULD HAVE THE BEST CHANCE OF FORMING OVER THE INLAND AND WESTERN LOCATIONS EACH AFTERNOON. MOISTURE BEGINS TO INCREASE ACROSS THE AREA BY FRI. MARINE... A TROUGH EXTENDING SOUTH OF A WEAK LOW PRESSURE AREA CENTERED NORTH OF THE BAHAMAS OR EAST SOUTHEAST OF CAPE CANAVERAL IS FORECAST TO TRACK WEST AND NORTHWEST ACROSS THE FLORIDA PENINSULA THROUGH TONIGHT. SCATTERED SHOWER AND STORMS ASSOCIATED WITH THIS FEATURE WILL LEAD TO PERIODS WITH REDUCED VISIBILITIES ALONG WITH LOCALLY HIGHER WINDS AND SEAS...ESPECIALLY ACROSS THE ATLANTIC WATERS. SUNDAY THROUGH THE MID WEEK PERIOD...MODERATE EASTERLY WINDS AND SEAS WILL BE ANTICIPATED AS TROPICAL STORM ERNESTO PASSES SOUTH OF THE MARINE AREA ACROSS THE CARIBBEAN SEA. FOR THE LATEST INFORMATION REGARDING ERNESTO...REFER TO THE LATEST FORECASTS AND ADVISORIES ISSUED BY THE NATIONAL HURRICANE CENTER. FIRE WEATHER... NO CONCERNS THROUGH THE WEEKEND AND INTO THE UPCOMING WEEK AS PLENTY OF MOISTURE AND RAIN CHANCES REMAIN IN THE FORECAST.SOME DRIER AIR WITH MODERATE EASTERLY FLOW APPEARS POSSIBLE THROUGH THE MID-WEEK PERIOD. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 88 79 88 / 20 60 40 60 FORT LAUDERDALE 79 90 80 89 / 20 60 40 60 MIAMI 78 89 79 89 / 20 60 40 60 NAPLES 76 92 76 90 / 50 50 40 60 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
741 PM EDT SAT AUG 4 2012 .UPDATE... THE SHOWERS AND THUNDERSTORMS HAVE SHIFTED INTO THE WESTERN AREAS OF SOUTH FLORIDA EARLY THIS EVENING WHERE BEST INSTABILITY IS LOCATED. SO HAVE INCREASED THE POPS FOR THE WESTERN AREAS...AND REDUCED THE POPS OVER THE EASTERN AREAS OF THE CWA FOR REST OF THE EVENING HOURS. && .UPDATE...54/BNB .PREV DISCUSSION... /ISSUED 154 PM EDT SAT AUG 4 2012/ SHORT TERM...(TONIGHT-MONDAY NIGHT) THE LATEST SURFACE ANALYSIS SHOWED A TROUGH EXTENDING SOUTH OF A WEAK LOW PRESSURE AREA CENTERED ALONG IT NORTHWEST OF THE BAHAMAS OR EAST SOUTHEAST OF FT PIERCE. LIGHT WNW FLOW ACROSS THE LOCAL AREA TO ITS SOUTHWEST COMBINED WITH THE ATLANTIC SEA BREEZE HAS ALREADY LED TO A FEW SHOWERS DEVELOPING ALONG IT OVER PALM BEACH COUNTY NEAR THE COAST AND FARTHER SOUTH ALONG THE EAST COAST AREAS. LOCAL WRF AND HRRR MODEL REFLECTIVITIES SEEM TO BE INITIALIZING WELL WITH THIS PATTERN AND GENERALLY INDICATE THIS ACTIVITY INCREASING IN COVERAGE THROUGH THE COURSE OF THE AFTERNOON TODAY AS THE ATL SEA BREEZE CONTINUES TO MAKE ITS PUSH INLAND. THIS COMBINED WITH THE ACTIVITY FROM YESTERDAY COULD GENERATE MORE FLOODING CONCERNS DEPENDING ON WHERE THE HEAVIEST ACTIVITY BECOMES CONCENTRATED AS THE DAY PROGRESSES. THE MORNING UPPER AIR SOUNDING AT MIAMI ALONG WITH THE LATEST SATELLITE DERIVED 500 MB TEMPERATURES INDICATE A MORE STABLE ENVIRONMENT COMPARED TO YESTERDAY AND WITH THE BEST INSTABILITY OR COOLER MID /UPPER-LEVEL AIR NOW TO THE WEST OF THE FL PENINSULA CLOSER TO THE BROAD UPPER LOW CENTER OVER THE GULF OF MEXICO. THEREFORE...THE MAIN IMPACTS FROM ANY STRONG STORMS THAT DO DEVELOP SHOULD REMAIN SUB-SEVERE AND MAINLY ASSOCIATED WITH STRONG WIND GUSTS UP TO 50 MPH. THE LATEST NUMERICAL MODEL GUIDANCE HAS INITIALIZED WELL WITH THIS SURFACE TROUGH AND LOW JUST EAST OF THE LOCAL AREA AND GENERALLY INDICATES THIS FEATURE CONTINUING WESTWARD OVER SOUTH FLORIDA THROUGH TONIGHT...THEN WEST OF THE FL PENINSULA SUNDAY THROUGH MONDAY. IN ITS WAKE...MOIST SOUTHEAST FLOW WILL BE EXPECTED AS THE AFOREMENTIONED SURFACE TROUGH/UPPER LOW CONTINUES WEST AND AWAY FROM THE FL PENINSULA AND ERNESTO CONTINUES ITS WESTWARD TRACK ACROSS THE CARIBBEAN SEA AND PASSES THE LOCAL AREA TO THE SOUTH SUNDAY THROUGH MONDAY NIGHT. MODERATE EAST AND SOUTHEAST FLOW THROUGH THE LOW LEVELS DUE TO A SLIGHTLY ENHANCED GRADIENT BETWEEN ERNESTO TO THE SOUTH AND THE SUBTROPICAL RIDGE TO THE NORTH COMBINED WITH PRECIPITABLE WATER VALUES AROUND THE TWO INCH MARK WILL KEEP THE RAIN CHANCES IN THE FORECAST THROUGH THE PERIOD. LONG TERM (TUESDAY-FRIDAY)... ATLANTIC HIGH PRESSURE WILL BUILD INTO SOUTH FL BEGINNING TUE AND LASTING THROUGH THE WORK WEEK WITH DRIER AIR MOVING IN FROM THE EAST. PWATS LOWER TO AROUND 1.5 INCHES WED-THU...WITH EVEN A LITTLE BIT OF HAZE FROM SAHARAN DUST POSSIBLY MOVING IN MID WEEK. WITH THE EASTERLY FLOW IN PLACE...SHOWERS/TSTMS THAT DEVELOP DURING THIS TIME SHOULD HAVE THE BEST CHANCE OF FORMING OVER THE INLAND AND WESTERN LOCATIONS EACH AFTERNOON. MOISTURE BEGINS TO INCREASE ACROSS THE AREA BY FRI. MARINE... A TROUGH EXTENDING SOUTH OF A WEAK LOW PRESSURE AREA CENTERED NORTH OF THE BAHAMAS OR EAST SOUTHEAST OF CAPE CANAVERAL IS FORECAST TO TRACK WEST AND NORTHWEST ACROSS THE FLORIDA PENINSULA THROUGH TONIGHT. SCATTERED SHOWER AND STORMS ASSOCIATED WITH THIS FEATURE WILL LEAD TO PERIODS WITH REDUCED VISIBILITIES ALONG WITH LOCALLY HIGHER WINDS AND SEAS...ESPECIALLY ACROSS THE ATLANTIC WATERS. SUNDAY THROUGH THE MID WEEK PERIOD...MODERATE EASTERLY WINDS AND SEAS WILL BE ANTICIPATED AS TROPICAL STORM ERNESTO PASSES SOUTH OF THE MARINE AREA ACROSS THE CARIBBEAN SEA. FOR THE LATEST INFORMATION REGARDING ERNESTO...REFER TO THE LATEST FORECASTS AND ADVISORIES ISSUED BY THE NATIONAL HURRICANE CENTER. FIRE WEATHER... NO CONCERNS THROUGH THE WEEKEND AND INTO THE UPCOMING WEEK AS PLENTY OF MOISTURE AND RAIN CHANCES REMAIN IN THE FORECAST.SOME DRIER AIR WITH MODERATE EASTERLY FLOW APPEARS POSSIBLE THROUGH THE MID-WEEK PERIOD. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 88 79 88 / 20 60 40 60 FORT LAUDERDALE 79 90 80 89 / 20 60 40 60 MIAMI 78 89 79 89 / 20 60 40 60 NAPLES 76 92 76 90 / 50 50 40 60 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
200 PM EDT FRI AUG 3 2012 .SYNOPSIS)... 18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS THE FLORIDA PENINSULA CONTINUES TO RESIDE UNDERNEATH A SUBTLE WEAKNESS IN THE HEIGHT FIELDS TO THE EAST OF AN IMPRESSIVE AND DOMINANT UPPER LEVEL RIDGE ACROSS THE SOUTHERN PLAINS. THIS UPPER RIDGE IS ACTUALLY ONE OF THE MORE VISUALLY IMPRESSIVE ANTICYCLONES ON WV IMAGERY THAT THIS FORECASTER HAS SEEN...WITH A VERY SYMMETRIC LOOK OF DRY AIR/SUPPRESSION AT ITS CORE AND RINGED BY A MID/UPPER LEVEL MOISTURE BELT. AT THE SURFACE...THE SUBTROPICAL RIDGE AXIS HAS SHIFTED NORTHWARD OVER THE PAST 24 HOURS AND IS NOW ALIGNED OVER THE NORTHERN FL PENINSULA/NE GULF OF MEXICO. ROTATING AROUND THE SOUTHERN PERIPHERY OF THIS RIDGE WE FIND A RATHER WELL DEFINED INVERTED TROUGH/TROPICAL WAVE FEATURES CROSSING THE BAHAMAS AND APPROACHING THE FL EAST COAST. && .SHORT TERM (THIS EVENING THROUGH SUNDAY NIGHT)... LATE AFTERNOON/EVENING...THE CURRENT THINKING ON THE MOST LIKELY CONVECTIVE CYCLE THROUGH THE EVENING IS FOR ISOLATED-WDLY SCT SHOWERS/STORMS EARLY/MID AFTERNOON MOVING SLOWLY INLAND FROM THE I-75 CORRIDOR. THEREAFTER...WITH THE APPROACH OF THE SURFACE WAVE FROM THE EAST...WILL SEE OUR 1000-700MB FLOW TRANSITION TO A MORE EASTERLY DIRECTION. THIS SYNOPTIC INFLUENCE SHOULD HELP PROPEL THE EAST COAST SEA-BREEZE ACROSS THE PENINSULA BY EARLY EVENING. THE INTERACTION OF BOTH SEA-BREEZES SHOULD BE GREATEST FROM TAMPA BAY SOUTHWARD WHERE A SECOND ROUND OF CONVECTION MAY ACTUALLY PUSH BACK TOWARD THE WEST COAST WITH TIME. MID-LEVEL CONVECTIVE POTENTIAL IS ACTUALLY VERY FAVORABLE FOR DEEP CONVECTION WITH THETAE VALUES IN THE LOWER 330S. OUR LOCAL HIRES GUIDANCE ALONG WITH SEVERAL OF THE NATIONAL HI-RES MEMBERS ARE SHOWING SOMETHING SIMILAR TO THIS SCENARIO. REST OF THE OVERNIGHT...DEVELOPING EASTERLY FLOW WILL PUSH ANY LINGERING CONVECTION OFFSHORE ALLOWING FOR A MOSTLY DRY OVERNIGHT PERIOD AFTER 02-03Z. NOT IMPOSSIBLE THAT A FEW SHOWERS MOVING ASHORE ALONG THE FL EAST COAST WITHIN THE EASTERLY FLOW COULD REACH FAR EASTERN PORTIONS OF THE AREA...HOWEVER MOST OF THIS ACTIVITY SHOULD DISSIPATE SHORTLY AFTER MOVING INLAND. SATURDAY/SATURDAY NIGHT... TROUGH/WAVE PASSES OVER THE CENTRAL/SOUTHERN PENINSULA AND REACHES THE WESTERN COAST BY EARLY EVENING. THE COMBINATION OF INCREASING COLUMN MOISTURE AND ENHANCED LOW LEVEL FOCUS ASSOCIATED WITH THIS FEATURE IS LIKELY TO RESULT IN A GOOD COVERAGE OF SHOWERS/STORMS DURING THE AFTERNOON/EVENING HOURS. CURRENT GRIDS SHOWING 40-50% POPS NORTH OF TAMPA BAY AND LIKELY 60% POPS FURTHER SOUTH. THE EASTERLY FLOW SHOULD ALSO HELP KEEP THE MAIN CONVECTIVE AXIS FROM MOVING INLAND AND AWAY FROM THE COAST. THEREFORE...WILL KEEP EQUAL CHANCES FOR RAIN THROUGH THE AFTERNOON FOR BOTH COASTAL AND INLAND ZONES. TEMPERATURES WILL BE HIGHLY DEPENDENT ON JUST HOW FAST THE CONVECTION GETS ACTIVE. DO ANTICIPATE QUITE A BIT OF DEBRIS CLOUD COVER BY THE END OF THE DAY. WILL ALLOW TEMPS TO REACH THE LOWER 90S FOR MOST LOCATIONS...HOWEVER ACTUAL HIGHS MAY BE A BIT LOWER. EVENING SHOWER AND STORMS WILL MIGRATE BACK OFFSHORE WITHIN THE EASTERLY FLOW BY THE LATER EVENING HOURS. MOST INLAND LOCATIONS WILL SEE A DRY OVERNIGHT PERIOD...WHILE PLENTY OF SHOWERS/STORMS ARE LIKELY TO BE ONGOING OVER THE COASTAL WATERS. ONE THING TO MENTION...AND ONE POTENTIAL ISSUE WITH THE FORECAST WOULD BE IF THE NAM SOLUTION WERE TO VERIFY. THE NAM IS CONSOLIDATING THE SURFACE WAVE MORE AS IT APPROACHES THE EAST COAST AND ACTUALLY CLOSING OFF A LOW. THIS PATTERN SLOWS THE OVERALL PROGRESS AND MOISTURE INFLUX. THE RESULT WOULD A DRIER FORECAST...ESPECIALLY SINCE THE LACK OF EASTERLY FLOW WOULD LESSEN THE OVERALL CONVERGENCE. AT THIS TIME...THIS SOLUTION IS AN OUTLIER AND WAS NOT CONSIDERED WITH THIS FORECAST PACKAGE. IT IS HARD TO ARGUE WITH A GUIDANCE CONSENSUS WHICH INCLUDES THE GFS/ECMWF/CMC AND SREF. SUNDAY...ANOTHER ACTIVE CONVECTIVE DAY APPEARS ON TAP. THE MAIN AXIS OF THE TROPICAL WAVE WILL HAVE MOVED OFFSHORE INTO THE EASTERN GULF...HOWEVER STILL SOME ENHANCED FOCUS AND A MOIST COLUMN WILL KEEP THE ATMOSPHERE FAVORABLE FOR DEEP CONVECTION. A 1000-700MB LOW LEVEL FLOW WILL ALSO KEEP THE BEST LOW LEVEL CONVERGENCE ALIGNED WITH THE WEST COAST SEA-BREEZE. OVERALL WE ARE NOT ANTICIPATING A WASHOUT OF A WEEKEND...BUT THOSE WITH OUTDOOR PLANS THE NEXT COUPLE OF DAYS SHOULD PREPARE FOR AT LEAST SOME RAINFALL. && .LONG TERM (MONDAY-THURSDAY)... AN U/L RIDGE WILL PERSIST OVER THE ATLANTIC EXTENDING OVER THE SOUTHERN PLAINS THROUGH THE PERIOD. SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC WITH THE RIDGE AXIS NORTH OF FLORIDA WILL ALSO PERSIST THROUGH THE PERIOD. EASTERLY BOUNDARY LAYER FLOW WILL HOLD THE WEST COAST SEA BREEZE NEAR THE COAST WITH AFTERNOON BOUNDARY COLLISIONS OVER WEST CENTRAL AND SOUTHWEST FLORIDA. DEEP TROPICAL MOISTURE OVER THE REGION WILL ALLOW NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP MONDAY AND TUESDAY AFTERNOONS. A FEW PULSE SEVERE STORMS ARE POSSIBLE EACH DAY. WILL HAVE TO MONITOR PROGRESS OF TROPICAL STORM ERNESTO NEAR THE WINDWARD ISLANDS AS CURRENT FORECAST TRACKS THE STORM INTO THE WESTERN CARIBBEAN TUESDAY AND WEDNESDAY. SUBSIDENCE AROUND THE PERIPHERY OF THE TROPICAL SYSTEM WILL INCREASE OVER THE FORECAST AREA WEDNESDAY AND THURSDAY WITH DECREASING AREAL COVERAGE OF AFTERNOON THUNDERSTORMS WITH INCREASING DAYTIME TEMPERATURES. DEPENDING ON STRENGTH OF ERNESTO...STRONG SUBSIDENCE AND EASTERLY BOUNDARY LAYER FLOW ACROSS WEST CENTRAL FLORIDA COULD ALLOW AFTERNOON TEMPERATURES TO CLIMB INTO THE MID 90S IN MANY AREAS WEDNESDAY AND THURSDAY. && .AVIATION... HIGHER CONFIDENCE NOW IN THUNDERSTORM ACTIVITY IMPACTING PGD..FMY...RSW AND LAL TAF SITES. TPA...PIE AND SRQ MAY SEE IMPACTS LATER IN THE AFTERNOON OR EVEN INTO THE EARLY EVENING AS EAST COAST ACTIVITY PUSHES WESTWARD. VFR OVERNIGHT AND THROUGH MID-DAY SATURDAY. && .MARINE... THE SUBTROPICAL RIDGE AXIS WILL CONTINUE TO MIGRATE NORTHWARD IN RESPONSE TO THE APPROACH OF A TROPICAL WAVE FROM THE EAST. THIS TROUGH WILL CROSS THE FL PENINSULA INTO THE SOUTHEAST GULF OF MEXICO TONIGHT AND SATURDAY AND THEN REMAIN OVER THE CENTRAL AND EASTERN GULF THROUGH THE REMAINDER OF THE WEEKEND. WINDS WILL BECOME MORE EASTERLY WITH TIME AND ARE GENERALLY EXPECTED TO REMAIN BELOW HEADLINE CRITERIA...HOWEVER THE PRESENCE OF THE SURFACE TROUGH WILL LIKELY INCREASE THE COVERAGE OF SHOWERS AND STORMS OVER THE FORECAST WATERS. && .FIRE WEATHER... AN INFLUX OF LOW LEVEL MOISTURE ASSOCIATED WITH A PASSING TROPICAL WAVE WILL KEEP RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS INTO THE EARLY PORTION OF NEXT WEEK...ALONG WITH DECENT CHANCES FOR MAINLY AFTERNOON AND EVENING SHOWERS AND STORMS. && .PRELIMINARY POINT TEMPS/POPS... TPA 77 92 77 91 / 30 50 20 50 FMY 76 93 76 93 / 30 60 30 50 GIF 74 94 75 94 / 30 50 20 50 SRQ 75 93 75 92 / 30 60 20 50 BKV 71 93 74 92 / 30 50 20 50 SPG 79 92 79 91 / 30 50 20 50 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA AVIATION...JILLSON LONG TERM...OGLESBY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1055 AM EDT FRI AUG 3 2012 .UPDATE (REST OF TODAY)... 14Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS THE FLORIDA PENINSULA CONTINUES TO RESIDE UNDERNEATH A SUBTLE WEAKNESS IN THE HEIGHT FIELDS TO THE EAST OF AN IMPRESSIVE AND DOMINANT UPPER LEVEL RIDGE ACROSS THE SOUTHERN PLAINS. THIS UPPER RIDGE IS ACTUALLY ONE OF THE MORE VISUALLY IMPRESSIVE ANTICYCLONES ON WV IMAGERY THAT THIS FORECASTER HAS SEEN...WITH A VERY SYMMETRIC LOOK OF DRY AIR/SUPPRESSION AT ITS CORE AND RINGED BY A MID/UPPER LEVEL MOISTURE BELT. LOOKING AT THE LARGER PICTURE...THE MAIN NORTHERN STREAM FLOW IS HELD BY THIS RIDGE UP ALONG THE U.S/CANADIAN BORDER. AN IMPRESSIVE DISTURBANCE WITHIN THIS FLOW IS CURRENTLY DROPPING OUT OF THE CANADIAN ROCKIES INTO THE HIGH PLAINS. THIS ENERGY WILL LIKELY BE THE FOCUS FOR A ROUND OF STRONG/SEVERE STORMS ACROSS THE HIGH PLAINS STATES LATER TODAY. AT THE SURFACE...THE SUBTROPICAL RIDGE AXIS HAS SHIFTED NORTHWARD OVER THE PAST 24 HOURS AND IS NOW ALIGNED OVER THE NORTHERN FL PENINSULA/NE GULF OF MEXICO. ROTATING AROUND THE SOUTHERN PERIPHERY OF THIS RIDGE WE FIND A RATHER WELL DEFINED INVERTED TROUGH/TROPICAL WAVE FEATURES CROSSING THE BAHAMAS AND APPROACHING THE FL EAST COAST. THIS FEATURE IS THE FOCUS FOR QUITE A BIT OF CONVECTION TO THE EAST OF FLORIDA...BUT SO FAR HAS NOT MOVES FAR ENOUGH WEST TO SIGNIFICANTLY INFLUENCE THE CONVECTIVE POTENTIAL FOR OUR REGION. MOSTLY SUNNY SKIES HAVE BEEN RULE ACROSS THE FL WEST COAST THIS MORNING. THIS NEAR MAX OF INSOLATION HAS ALLOWED TEMPS TO QUICKLY WARM INTO THE MID/UPPER 80S...AND WE ARE JUST ABOUT AT THE POINT TO INITIATE THE SEA-BREEZE. WILL SEE A SCT CU FIELD BEGIN DEVELOPING WITH THIS SEA-BREEZE WITHIN THE NEXT HOUR OR 2...ALONG WITH A FEW ISOLATED SHOWERS. THE CURRENT THINKING ON THE MOST LIKELY CONVECTIVE CYCLE FOR THE REMAINDER OF THE DAY WILL BE FOR ISOLATED-WDLY SCT SHOWERS/STORMS EARLY THIS AFTERNOON WHICH WILL MIGRATE INLAND FROM THE I-75 CORRIDOR. THEREAFTER...WITH THE APPROACH OF THE SURFACE WAVE FROM THE EAST...WILL SEE OUR 1000-700MB FLOW TRANSITION TO A MORE EASTERLY DIRECTION. THIS SYNOPTIC INFLUENCE SHOULD HELP PROPEL THE EAST COAST SEA-BREEZE ACROSS THE PENINSULA BY LATE AFTERNOON/EARLY EVENING. THE INTERACTION OF BOTH SEA-BREEZES SHOULD BE GREATEST FROM TAMPA BAY SOUTHWARD WHERE A SECOND ROUND OF CONVECTION MAY ACTUALLY PUSH BACK TOWARD THE WEST COAST WITH TIME. MID-LEVEL CONVECTIVE POTENTIAL IS ACTUALLY VERY FAVORABLE FOR DEEP CONVECTION WITH THETAE VALUES IN THE LOWER 330S. OUR LOCAL HIRES GUIDANCE ALONG WITH SEVERAL OF THE NATIONAL HI-RES MEMBERS ARE SHOWING SOMETHING SIMILAR TO THIS SCENARIO. && .PREVIOUS DISCUSSION (TONIGHT THROUGH SUNDAY)... THE TROUGHINESS ALOFT CONTINUES TO WEAKEN AS IT SLIDES WEST OVER THE GULF AS THE UPPER RIDGE IN THE ATLANTIC BEGIN TO BUILD SOUTHWESTWARD TODAY. THE SURFACE RIDGE AXIS LIFTS UP INTO NORTHERN FL AS THE TROPICAL WAVE APPROACHES THE EAST FL COAST. ON SAT - THE UPPER RIDGE SPREADS OVER FL AS THE SURFACE RIDGE AXIS MOVES INTO SOUTHERN GA WITH THE TROPICAL WAVES CROSSING THE STATE TO THE WEST COAST. FOR SUN - BOTH THE UPPER AND SURFACE RIDGES PIVOT NORTH... TO THE SE U,S. COAST AS THE WAVE SLIDES OUT OVER THE GULF. THE SW AND WEST LOW LEVEL FLOW OF THE PAST FEW DAYS WILL GIVE WAY TO SOUTHEAST AND THEN EASTERLY FLOW AS THE RIDGE AXIS MOVES NORTH AND THE WAVE CROSSES THE AREA. THE PREVAILING LOW LEVEL FLOW THEN BACKS TO SE SUN AS THE RIDGE CONTINUES NORTH AND THE WAVE MOVES AWAY. THE FLOW WILL BE LIGHT ENOUGH FOR SEA BREEZE CIRCULATIONS EACH DAY...HOWEVER THE MORE EASTERLY FLOW SAT WILL KEEP THE SEA BREEZE CLOSE TO THE COAST. THE ATMOSPHERE MOISTENS WITH PWAT VALES RUNNING OVER 2 INCHES THROUGH THE WEEKEND. THE FORECAST WILL BE TYPICAL FOR EARLY AUGUST. THE MOIST AIR MASS...SEA BREEZE CONVERGENCE...AND DAY TIME HEATING WILL RESULT IN ISOLATED BECOMING SCATTERED CONVECTION DURING THE DAY THAT LINGERS INTO THE EVENING. EXCEPT SUN WILL SEE NUMEROUS STORMS OVER COASTAL LOCATIONS DUE TO A MORE ROBUST SEA BREEZE. THIS PATTERN FAVORS A FEW STORMS BECOMING STRONG WITH THE GREATEST THREAT WIND. TEMPERATURES WILL RUN JUST ABOVE NORMAL ALTHOUGH THE HIGHS WILL DIP A DEGREE OR TWO BETWEEN THIS AFTERNOON AND SUN. && .AVIATION... MAINLY VFR TODAY WITH JUST ISOLATED TO WIDELY SCATTERED STORMS AROUND AFTER 15Z. CONFIDENCE IN COVERAGE AND TIMING TOO LOW TO INCLUDE TEMPO GROUPS AT THIS TIME. && .MARINE... SOUTH AND SW WINDS WITH AN AFTERNOON SEA BREEZE FOR TODAY WILL SHIFT TO SE AND EAST FOR THE WEEKEND AND EARLY NEXT WEEK...BUT WITH A SEA BREEZE NEAR THE COAST IN THE AFTERNOONS. WITH WIND SPEEDS OF 10 KT OR LESS THE MAIN MARINE HAZARD WILL BE ISOLATED TO SCATTERED THUNDERSTORMS. && .PRELIMINARY POINT TEMPS/POPS... TPA 92 77 92 76 / 40 20 40 30 FMY 93 75 92 75 / 40 20 50 30 GIF 94 74 93 74 / 40 30 50 20 SRQ 92 75 92 75 / 40 20 40 30 BKV 93 71 92 72 / 30 20 40 30 SPG 91 79 91 76 / 30 20 40 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE...MROCZKA AVIATION...JILLSON PREVIOUS DISCUSSION...RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
912 PM CDT SAT AUG 4 2012 .DISCUSSION... ISSUED 900 PM CDT SAT AUG 4 2012 HI RES MODELS ARE STILL INDICATING WE SHOULD SEE SOME STORM DEVELOPMENT ALONG THE COLD FRONT LATE THIS EVENING AND AFTER MIDNIGHT. INSTABILITY PARAMS CONTINUE TO LOOK FAVORABLE FOR STORMS AHEAD OF THE FRONT EVEN INTO CENTRAL AND SOUTHEAST IL. WE WILL CONTINUE WITH AT LEAST HIGH CHANCE POPS...ALTHOUGH WE MAY PULL BACK ON THE LIKELY POPS...OR DIMINISH THE COVERAGE OF LIKELY POPS. CAN NOT RULE OUT A FEW STRONG STORMS WITH DAMAGING WINDS POSSIBLE. STORMS IN EAST CENTRAL MISSOURI HAVE REACHED SEVERE LEVELS AND THEY ARE APPROACHING SW ILLINOIS. THEIR PROGRESSION WOULD MOSTLY LIKELY HAVE THEM AFFECTING OUR SOUTHEASTERN COUNTIES. VARIABLE CLOUD COVER THE REST OF THE NIGHT...COUPLED WITH COLDER AIR LAGGING WELL BEHIND THE COLD FRONT...SHOULD SET THE STAGE FOR LOWS TO REMAIN IN THE UPPER 60S TO LOW 70S. DRY AND NOT AS HOT FOR SUNDAY...WITH SUNDAY NIGHTS LOWS DIPPING INTO THE 50S. MAIN UPDATES WERE TO THE POP AND WEATHER GRIDS. UPDATED INFO WILL BE AVAIL SHORTLY. SHIMON && .AVIATION... ISSUED 659 PM CDT SAT AUG 4 2012...FOR THE 00Z TAFS THE COLD FRONT IS STILL PROGRESSING INTO CENTRAL IL FROM THE NW. AT 23Z IT EXTENDED FROM COLUMBIA MO TO NEAR GALESBURG. THE MORE ACTIVE PORTION OF THE FRONT WAS IN MISSOURI AND FAR NE OKLAHOMA. SOME INSTABILITY STILL RESIDES IN OUR COUNTIES...BUT NOT AS FAVORABLE FOR SEVERE AS FARTHER SOUTHWEST. THE HRRR MODEL INDICATES SOME STORMS WILL DEVELOP FM SW TO NE ALONG THE I-55 CORRIDOR AND SLIDE EAST. SPI/DEC/CMI WILL HAVE THE BEST CHANCES OF BEING AFFECTED BY THOSE STORMS. CAN NOT RULE OUT SOME BREAKS IN THE LINE, SO WE DECIDED TO ONLY USE VCSH THIS EVENING FOR NOW. WINDS HAVE SHIFTED NORTH AT THE TERMINAL SITES DUE TO THE OUTFLOW FROM THE STORMS NORTH OF I-74 LATE THIS AFTERNOON. WINDS MAY RETURN TO SW FOR A TIME AHEAD OF THE FRONT. FROPA SHOULD OCCUR THIS EVENING BETWEEN 02Z AT PIA THROUGH 06Z AT CMI. WINDS WILL INCREASE TO 12-14KT FROM THE NORTH TOMORROW AS HIGH PRESSURE BUILDS INTO THE AREA BEHIND THE FRONT. IFR VIS AND CIGS WILL BE POSSIBLE IF ANY STORMS AFFECT ONE OF THE TERMINALS. WILL UPDATE AS THE LINE OF STORMS DEVELOPS ALONG THE FRONT THIS EVENING. SHIMON && .PREV DISCUSSION... ISSUED 341 PM CDT SAT AUG 4 2012 COLD FRONT HAS BEEN MOVING A BIT QUICKER TOWARD THE CWA...AND WAS LOCATED FROM NEAR THE QUAD CITIES SOUTHWEST TO NEAR KANSAS CITY. WELL-DEFINED MESOSCALE VORTEX FROM CONVECTION IN IOWA HELPED TO DEVELOPED AN MCS WHICH HAS BEEN ROLLING ACROSS THE NORTHERN THIRD OF ILLINOIS THIS AFTERNOON. SOME OF THE SOUTHERN FRINGES CONTINUE TO PUSH ACROSS AREAS FROM CANTON EAST TO EL PASO AT MID AFTERNOON. INSTABILITY OVER THE AREA PEAKED EARLY THIS AFTERNOON WITH CAPES AROUND 4000 J/KG...BUT SPC MESO-ANALYSIS HAS BEEN SHOWING SOME DECREASE IN CAPES AND INCREASE IN CAPPING ALOFT. HOWEVER...STILL QUITE A BIT OF INSTABILITY AVAILABLE FROM SOUTHERN MISSOURI NORTHEAST INTO EAST CENTRAL ILLINOIS. LATEST NAM AND HRRR SHOW DEVELOPMENT OCCURRING IN THESE AREAS OVER THE NEXT COUPLE HOURS. WILL MAINTAIN LIKELY POPS OVER A LARGE PART OF THE CWA THIS EVENING...THEN LIMIT THEM TO 40-50 PERCENT AFTER MIDNIGHT ACROSS THE EAST CENTRAL AND SOUTHEAST CWA. ANY LINGERING RAIN ACROSS THE FAR SOUTHEAST WILL LIKELY BE ENDING BEFORE SUNRISE. LITTLE CHANGE MADE TO THE REMAINDER OF THE FORECAST. BRIEF COOL DOWN WILL BE NOTED EARLY THIS WEEK AS HIGH PRESSURE DRIFTS EAST ACROSS THE AREA. A SLOW WARMING TREND WILL BRING TEMPERATURES BACK TO NEAR 90 MUCH OF THE REMAINDER OF THE WEEK...WITH HOTTER WEATHER KNOCKING ON THE DOOR AS WE REMAIN ON THE FRINGE OF THE UPPER RIDGING ACROSS THE WESTERN HALF OF THE NATION. MAIN FEATURE OF CONCERN IN THE LONG RANGE IS ON THURSDAY AND FRIDAY...WHEN A PIECE OF ENERGY DROPS SOUTHEAST OUT OF THE CANADIAN PRAIRIES. GFS AND ECMWF NOT TOO FAR APART WITH THE TRACK OF THIS SHORTWAVE OVER THE GREAT LAKES...BUT THE GFS IS MORE AGGRESSIVE WITH BRINGING RAIN CHANCES ALL THE WAY SOUTH ACROSS ILLINOIS. WILL KEEP SOME SLIGHT CHANCES IN THE GRIDS THURSDAY AND THURSDAY NIGHT...BUT WILL LEAN MORE TOWARD THE ECMWF WITH ITS ODDS OF DRY WEATHER. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
659 PM CDT SAT AUG 4 2012 .DISCUSSION... ISSUED 341 PM CDT SAT AUG 4 2012 COLD FRONT HAS BEEN MOVING A BIT QUICKER TOWARD THE CWA...AND WAS LOCATED FROM NEAR THE QUAD CITIES SOUTHWEST TO NEAR KANSAS CITY. WELL-DEFINED MESOSCALE VORTEX FROM CONVECTION IN IOWA HELPED TO DEVELOPED AN MCS WHICH HAS BEEN ROLLING ACROSS THE NORTHERN THIRD OF ILLINOIS THIS AFTERNOON. SOME OF THE SOUTHERN FRINGES CONTINUE TO PUSH ACROSS AREAS FROM CANTON EAST TO EL PASO AT MID AFTERNOON. INSTABILITY OVER THE AREA PEAKED EARLY THIS AFTERNOON WITH CAPES AROUND 4000 J/KG...BUT SPC MESO-ANALYSIS HAS BEEN SHOWING SOME DECREASE IN CAPES AND INCREASE IN CAPPING ALOFT. HOWEVER...STILL QUITE A BIT OF INSTABILITY AVAILABLE FROM SOUTHERN MISSOURI NORTHEAST INTO EAST CENTRAL ILLINOIS. LATEST NAM AND HRRR SHOW DEVELOPMENT OCCURRING IN THESE AREAS OVER THE NEXT COUPLE HOURS. WILL MAINTAIN LIKELY POPS OVER A LARGE PART OF THE CWA THIS EVENING...THEN LIMIT THEM TO 40-50 PERCENT AFTER MIDNIGHT ACROSS THE EAST CENTRAL AND SOUTHEAST CWA. ANY LINGERING RAIN ACROSS THE FAR SOUTHEAST WILL LIKELY BE ENDING BEFORE SUNRISE. LITTLE CHANGE MADE TO THE REMAINDER OF THE FORECAST. BRIEF COOL DOWN WILL BE NOTED EARLY THIS WEEK AS HIGH PRESSURE DRIFTS EAST ACROSS THE AREA. A SLOW WARMING TREND WILL BRING TEMPERATURES BACK TO NEAR 90 MUCH OF THE REMAINDER OF THE WEEK...WITH HOTTER WEATHER KNOCKING ON THE DOOR AS WE REMAIN ON THE FRINGE OF THE UPPER RIDGING ACROSS THE WESTERN HALF OF THE NATION. MAIN FEATURE OF CONCERN IN THE LONG RANGE IS ON THURSDAY AND FRIDAY...WHEN A PIECE OF ENERGY DROPS SOUTHEAST OUT OF THE CANADIAN PRAIRIES. GFS AND ECMWF NOT TOO FAR APART WITH THE TRACK OF THIS SHORTWAVE OVER THE GREAT LAKES...BUT THE GFS IS MORE AGGRESSIVE WITH BRINGING RAIN CHANCES ALL THE WAY SOUTH ACROSS ILLINOIS. WILL KEEP SOME SLIGHT CHANCES IN THE GRIDS THURSDAY AND THURSDAY NIGHT...BUT WILL LEAN MORE TOWARD THE ECMWF WITH ITS ODDS OF DRY WEATHER. GEELHART && .AVIATION... ISSUED 659 PM CDT SAT AUG 4 2012...FOR THE 00Z TAFS THE COLD FRONT IS STILL PROGRESSING INTO CENTRAL IL FROM THE NW. AT 23Z IT EXTENDED FROM COLUMBIA MO TO NEAR GALESBURG. THE MORE ACTIVE PORTION OF THE FRONT WAS IN MISSOURI AND FAR NE OKLAHOMA. SOME INSTABILITY STILL RESIDES IN OUR COUNTIES...BUT NOT AS FAVORABLE FOR SEVERE AS FARTHER SOUTHWEST. THE HRRR MODEL INDICATES SOME STORMS WILL DEVELOP FM SW TO NE ALONG THE I-55 CORRIDOR AND SLIDE EAST. SPI/DEC/CMI WILL HAVE THE BEST CHANCES OF BEING AFFECTED BY THOSE STORMS. CAN NOT RULE OUT SOME BREAKS IN THE LINE, SO WE DECIDED TO ONLY USE VCSH THIS EVENING FOR NOW. WINDS HAVE SHIFTED NORTH AT THE TERMINAL SITES DUE TO THE OUTFLOW FROM THE STORMS NORTH OF I-74 LATE THIS AFTERNOON. WINDS MAY RETURN TO SW FOR A TIME AHEAD OF THE FRONT. FROPA SHOULD OCCUR THIS EVENING BETWEEN 02Z AT PIA THROUGH 06Z AT CMI. WINDS WILL INCREASE TO 12-14KT FROM THE NORTH TOMORROW AS HIGH PRESSURE BUILDS INTO THE AREA BEHIND THE FRONT. IFR VIS AND CIGS WILL BE POSSIBLE IF ANY STORMS AFFECT ONE OF THE TERMINALS. WILL UPDATE AS THE LINE OF STORMS DEVELOPS ALONG THE FRONT THIS EVENING. SHIMON && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
332 PM CDT FRI AUG 3 2012 .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... FOCUS THROUGHOUT THE SHORT/MID RANGE WILL BE ON SYSTEM MOVING THROUGH THE REGION TONIGHT THROUGH SATURDAY NIGHT...AND ASSOCIATED COLD FRONT DROPPING THROUGH THE STATE. INITIALLY LINGERING ACTIVITY FROM EARLIER TODAY TO THE NORTHWEST HAS JUST DIMINISHED IN THE PAST FEW HOURS ACROSS NORTHWEST IOWA ASSOCIATED WITH SOME WEAK ENERGY ALOFT PUSHING OUT AHEAD OF THE MAIN WAVE. HRRR ADVERTISES SOME REDEVELOPMENT ACROSS THE NORTH CENTRAL CWA WITH THIS ENERGY...AND HAVE A FEW WEAK CELLS POPPING JUST TO THE NE OF THE CWA. ALSO HAVE DECENT CU FIELD EXTENDING BACK INTO THE CWA...WITH ANOTHER CU FIELD SITUATED ACROSS THE EXTREME SOUTHERN CWA NORTH OF ONGOING MCS THAT HAS BEEN IN PLACE ACROSS MO ALL DAY. THEREFORE HAVE SOME SLIGHT CHANCE POPS IN THE NORTH AND SOUTH THROUGH THE REMAINDER OF THE AFTERNOON HOURS WITH SPC MESODATA SUGGESTING SUFFICIENT INSTABILITY IN PLACE AND DECENT SHEAR ACROSS THE NORTH. THEREFORE AN ISOLATED SEVERE STORM CANNOT BE RULED EITHER ACROSS THE NORTH WITH ANY ACTIVITY THAT MAY DEVELOP. OTHERWISE GREATER CHANCE FOR PRECIPITATION/CONVECTION LATER TONIGHT AS STORMS CONTINUE TO DEVELOP IN VICINITY OF THE SFC FRONT SITUATED ACROSS CENTRAL SD INTO CENTRAL NE. AS THE MAIN UPPER WAVE PUSHES EAST ACROSS THE DAKOTAS AND INTO MINNESOTA SATURDAY...ASSOCIATED COLD FRONT WILL SWEEP ACROSS THE STATE...WITH SHOWERS AND THUNDERSTORMS EXPECTED TO BE ONGOING ACROSS THE NORTHWESTERN CWA SATURDAY MORNING AND CONTINUING TO TRACK EASTWARD SLOWLY DIMINISHING WITH TIME. FRONT WILL THEN PUSH INTO THE EASTERN CWA IN THE AFTERNOON HOURS...WITH REDEVELOPMENT EXPECTED BY LATE AFTERNOON ALONG THE FRONT...WITH THE FRONT EXITING THE CWA BY EARLY TO LATE EVENING AS THE UPPER SYSTEM TRACKS INTO THE GREAT LAKES REGION. THEREFORE HAVE GREATEST POPS FOR SATURDAY ACROSS THE CWA...WITH BEST CHANCE OF WIDER SPREAD PRECIPITATION AS THE AREA HAS SEEN IN A FEW WEEKS. MUCH COOLER AIR MOVING IN BEHIND THE FRONT...WITH H85 TEMPS DROPPING INTO THE LOWER TEENS TO MID TEENS CELSIUS ALOFT. THEREFORE MAX TEMPS TO BE COOLER IN AREAS BEHIND THE FRONT SATURDAY...WITH MANY SITES NOT MAKING IT OUT OF THE 70S ACROSS NORTHWESTERN IOWA AND MUCH COOLER CONDITIONS ACROSS THE ENTIRE STATE FOR SUNDAY. HIGHS SUNDAY EXPECTED TO TOP OUT IN THE 70S NORTH TO MID 80S SOUTH...WITH A QUICK CHANGE TO RETURN FLOW MONDAY AND MID 80S TO 90S WITH DRY CONDITIONS SUNDAY INTO MONDAY. ANOTHER WEAK SHORTWAVE DROPS DOWN THROUGH THE REGION MONDAY NIGHT IN NORTHWEST FLOW PATTERN ALOFT. THEREFORE COULD SEE A CHANCE FOR SOME NOCTURNAL THUNDERSTORMS MONDAY NIGHT ACROSS MUCH OF THE CWA. .LONG TERM /TUESDAY THROUGH FRIDAY/... BOTH GFS AND EURO NOW INDICATE BROAD NORTHWEST FLOW INTO NEXT WEEK AS UPPER RIDGING RETROGRADES INTO THE ROCKIES. THIS SHOULD DO A COUPLE OF THIS FOR IOWA...FIRST TEMPERATURES WILL LIKELY REMAIN COOLER DURING THE NEXT WEEK THAN WHAT PREVIOUS FORECASTS HAD GOING. READINGS ARE EXPECTED TO BE CLOSE TO NORMAL OR SLIGHTLY ABOVE BUT NOT THE 10 TO 15 DEGREE DEPARTURES WE SAW DURING MUCH OF JULY. SECOND...THE THREAT OF PRECIPITATION SHOULD BE GREATER AS WEAK SHORTWAVES IN THE FLOW DROP INTO THE MIDWEST. THE MAIN PROBLEM WITH THESE IS MORE OF A TIMING ISSUE AS IS OFTEN TYPICAL IN NORTHWEST FLOW. THESE CONDITIONS WILL CERTAINLY PROVIDE SOME RELIEF FROM THE INTENSIFYING DROUGHT WITH BOTH MODELS INDICATING THE NORTHWEST FLOW CONTINUING BEYOND THE FORECAST PERIOD. && .AVIATION...03/18Z INCREASING CLOUDS EXPECTED THROUGHOUT THE PERIOD...MAINLY HIGH CLOUDS IN THE CRITICAL TAF PERIOD AS UPPER LEVEL SYSTEM SLIDES EASTWARD THROUGH THE DAKOTAS INTO MINNESOTA. AN ASSOCIATED COLD FRONT WILL SWEEP THROUGH THE STATE SATURDAY INTO JUST BEYOND THE CURRENT TAF PERIOD ALLOWING WINDS TO SHIFT AROUND TO THE NORTHWEST BEHIND THE FRONT. THIS SYSTEM WILL ALSO BRING CHANCES FOR THUNDERSTORMS TO THE AREA...WITH THE GREATEST CERTAINTY AT KFOD AND KMCW AT THIS TIME THROUGH 18Z SATURDAY. THEREFORE HAVE HIGHLIGHTED WITH A VCSH AWAITING FURTHER REFINEMENT AS THE SYSTEM APPROACHES. GREATER CHANCES FOR EASTERN/SOUTHERN TAF SITES FOR PRECIP JUST BEYOND THE CURRENT TAF PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...MJB LONG TERM...COGIL AVIATION...MJB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1215 PM CDT FRI AUG 3 2012 .SHORT TERM /TODAY/... MOST IMMEDIATE CONCERN INVOLVES FATE OF SMALL MCS ALONG SD/NE BORDER. CLUSTER IS ELEVATED...MOST LIKELY ALONG 310K ISENT SURFACE...WITHIN STRONG MLCIN. RAP SUGGESTS MOISTURE TRANSPORT AND CONVERGENCE ALONG THIS SURFACE WILL MAINTAIN ITSELF TO OUR WEST WITH LITTLE MOVEMENT INTO THE MORNING SO WILL LEAVE OUR FORECAST DRY TODAY. RECENT UPSTREAM DEVELOPMENT SUPPORTS THIS SCENARIO AS WELL. NONE OF THE EXPLICIT OR PARAMETERIZED MODEL GUIDANCE SUGGESTS THIS WILL MAINTAIN ITSELF EASTWARD INTO IA EITHER. NEXT CONCERN WILL BE TEMPS. FORECAST SOUNDINGS AND LOW LEVEL TEMP CHANGE FROM YESTERDAY SUGGEST HIGHS MAY BE A FEW DEGREES WARMER WHICH MAKES SENSE AS LOW LEVEL WINDS SLOWLY VEER AND INCREASE SLIGHTLY. TRIMMING A FEW DEGREES OFF THE OFTEN OVERAGGRESSIVE TOO SUPER ADIABATIC NAM SUGGESTS HIGHS IN THE MID/UPPER 90S. LOWERING DEWPOINTS WITH MIXING THIS AFTERNOON WILL KEEP HEAT INDICES PLUS/MINUS A FEW DEGREES OF THE ACTUAL TEMPERATURE. .LONG TERM /TONIGHT THROUGH THURSDAY/... MODELS ARE A LITTLE SLOWER WITH THE SHORTWAVE TONIGHT ALSO THE BEST FORCING. AS A RESULT A BACKED OFF ON POPS THIS EVENING AND ON AREAL EXTENT OF POPS OVERNIGHT. UPPER TROUGH AND SURFACE COLD FRONT MOVE THROUGH MOST OF CENTRAL IOWA DURING THE MORNING INTO EARLY AFTERNOON. WHILE THE SYSTEM IS DYNAMIC...IT MOVES THROUGH MUCH OF THE CWA BEFORE PEAK HEATING SO THE BEST INSTABILITY WON/T BE REALIZED UNTIL THE SYSTEM IS MOSTLY EAST OF THE CWA. THE INTERESTING THING TO FORECAST FOR SATURDAY WILL BE TEMPS. SOUNDINGS SHOW THE DAYS HIGHS OCCURRING AROUND 18Z THEN BEGINNING TO FALL OFF. CLOUDS/PRECIP WILL IMPACT THE CWA AND THERE WILL LIKELY BE A PRETTY BIG THERMAL GRADIENT ACROSS THE STATE WITH MID 70S NORTHWEST AND MID 90S SOUTHEAST. SUNDAY WILL SEEM LIKE FALL WITH HIGHS IN THE 70S AND 80S. THIS WILL BE SHORT LIVED HOWEVER AS THE UPPER RIDGE REBUILDS OVER THE WEST EARLY NEXT WEEK. WHILE TEMPS ARE FORECAST TO WARM BACK UP INTO THE 80S AND 90S...IT WILL NOT BE AS WARM AS IT HAS BEEN. NUMEROUS SHORTWAVES WILL RIDE ATOP THE RIDGE ACROSS IOWA BUT TIMING AND STRENGTH OF THESE WAVES LEAVES THE POP FORECAST DIFFICULT AT BEST. MODELS DIFFER ON INTENSITY AND TIMING BUT IN THE TUESDAY NIGHT/WEDNESDAY TIMEFRAME ONE WAVE LOOKS LIKE IT WILL AFFECT THE WESTERN PORTION OF THE FORECAST AREA. ANOTHER STRONGER WAVE MOVES IN LATE IN THE EXTENDED...AROUND FRIDAY/FRIDAY NIGHT. POPS WERE HIT HARDEST DURING THIS TIME BUT WITH MODEL DISCREPANCIES AND WEAKER WAVES IN BETWEEN THE AFOREMENTIONED DAYS...I DID NOT FEEL SLIGHT POPS WERE WARRANTED. HOWEVER...AS RESOLUTION BECOMES BETTER...WE WILL LIKELY SEE OTHER PERIODS OF PRECIP DURING THE EXTENDED. && .AVIATION...03/18Z INCREASING CLOUDS EXPECTED THROUGHOUT THE PERIOD...MAINLY HIGH CLOUDS IN THE CRITICAL TAF PERIOD AS UPPER LEVEL SYSTEM SLIDES EASTWARD THROUGH THE DAKOTAS INTO MINNESOTA. AN ASSOCIATED COLD FRONT WILL SWEEP THROUGH THE STATE SATURDAY INTO JUST BEYOND THE CURRENT TAF PERIOD ALLOWING WINDS TO SHIFT AROUND TO THE NORTHWEST BEHIND THE FRONT. THIS SYSTEM WILL ALSO BRING CHANCES FOR THUNDERSTORMS TO THE AREA...WITH THE GREATEST CERTAINTY AT KFOD AND KMCW AT THIS TIME THROUGH 18Z SATURDAY. THEREFORE HAVE HIGHLIGHTED WITH A VCSH AWAITING FURTHER REFINEMENT AS THE SYSTEM APPROACHES. GREATER CHANCES FOR EASTERN/SOUTHERN TAF SITES FOR PRECIP JUST BEYOND THE CURRENT TAF PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...BSS LONG TERM...FAB AVIATION...MJB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
630 AM CDT FRI AUG 3 2012 .SHORT TERM /TODAY/... MOST IMMEDIATE CONCERN INVOLVES FATE OF SMALL MCS ALONG SD/NE BORDER. CLUSTER IS ELEVATED...MOST LIKELY ALONG 310K ISENT SURFACE...WITHIN STRONG MLCIN. RAP SUGGESTS MOISTURE TRANSPORT AND CONVERGENCE ALONG THIS SURFACE WILL MAINTAIN ITSELF TO OUR WEST WITH LITTLE MOVEMENT INTO THE MORNING SO WILL LEAVE OUR FORECAST DRY TODAY. RECENT UPSTREAM DEVELOPMENT SUPPORTS THIS SCENARIO AS WELL. NONE OF THE EXPLICIT OR PARAMETERIZED MODEL GUIDANCE SUGGESTS THIS WILL MAINTAIN ITSELF EASTWARD INTO IA EITHER. NEXT CONCERN WILL BE TEMPS. FORECAST SOUNDINGS AND LOW LEVEL TEMP CHANGE FROM YESTERDAY SUGGEST HIGHS MAY BE A FEW DEGREES WARMER WHICH MAKES SENSE AS LOW LEVEL WINDS SLOWLY VEER AND INCREASE SLIGHTLY. TRIMMING A FEW DEGREES OFF THE OFTEN OVERAGGRESSIVE TOO SUPER ADIABATIC NAM SUGGESTS HIGHS IN THE MID/UPPER 90S. LOWERING DEWPOINTS WITH MIXING THIS AFTERNOON WILL KEEP HEAT INDICES PLUS/MINUS A FEW DEGREES OF THE ACTUAL TEMPERATURE. .LONG TERM /TONIGHT THROUGH THURSDAY/... MODELS ARE A LITTLE SLOWER WITH THE SHORTWAVE TONIGHT ALSO THE BEST FORCING. AS A RESULT A BACKED OFF ON POPS THIS EVENING AND ON AREAL EXTENT OF POPS OVERNIGHT. UPPER TROUGH AND SURFACE COLD FRONT MOVE THROUGH MOST OF CENTRAL IOWA DURING THE MORNING INTO EARLY AFTERNOON. WHILE THE SYSTEM IS DYNAMIC...IT MOVES THROUGH MUCH OF THE CWA BEFORE PEAK HEATING SO THE BEST INSTABILITY WON/T BE REALIZED UNTIL THE SYSTEM IS MOSTLY EAST OF THE CWA. THE INTERESTING THING TO FORECAST FOR SATURDAY WILL BE TEMPS. SOUNDINGS SHOW THE DAYS HIGHS OCCURRING AROUND 18Z THEN BEGINNING TO FALL OFF. CLOUDS/PRECIP WILL IMPACT THE CWA AND THERE WILL LIKELY BE A PRETTY BIG THERMAL GRADIENT ACROSS THE STATE WITH MID 70S NORTHWEST AND MID 90S SOUTHEAST. SUNDAY WILL SEEM LIKE FALL WITH HIGHS IN THE 70S AND 80S. THIS WILL BE SHORT LIVED HOWEVER AS THE UPPER RIDGE REBUILDS OVER THE WEST EARLY NEXT WEEK. WHILE TEMPS ARE FORECAST TO WARM BACK UP INTO THE 80S AND 90S...IT WILL NOT BE AS WARM AS IT HAS BEEN. NUMEROUS SHORTWAVES WILL RIDE ATOP THE RIDGE ACROSS IOWA BUT TIMING AND STRENGTH OF THESE WAVES LEAVES THE POP FORECAST DIFFICULT AT BEST. MODELS DIFFER ON INTENSITY AND TIMING BUT IN THE TUESDAY NIGHT/WEDNESDAY TIMEFRAME ONE WAVE LOOKS LIKE IT WILL AFFECT THE WESTERN PORTION OF THE FORECAST AREA. ANOTHER STRONGER WAVE MOVES IN LATE IN THE EXTENDED...AROUND FRIDAY/FRIDAY NIGHT. POPS WERE HIT HARDEST DURING THIS TIME BUT WITH MODEL DISCREPANCIES AND WEAKER WAVES IN BETWEEN THE AFOREMENTIONED DAYS...I DID NOT FEEL SLIGHT POPS WERE WARRANTED. HOWEVER...AS RESOLUTION BECOMES BETTER...WE WILL LIKELY SEE OTHER PERIODS OF PRECIP DURING THE EXTENDED. && .AVIATION...03/12Z VFR CONDITIONS EXPECTED THROUGH MUCH OF THE PERIOD WITH NOTHING MORE THAN SCT-BKN MID CLOUDS AT BEST. ONLY OTHER CONCERN WOULD BE THE POSSIBILITY OF CONVECTION AFFECTING NORTH AND WEST SITES /KFOD/KMCW/ EARLY SAT MORNING. CONFIDENCE IN THIS OCCURRENCE...TIMING AND LOCATION...AS WELL AS POTENTIAL THUNDER AND/OR LOWER CATEGORY CONDITIONS...ARE TOO LOW TO ADDRESS AT THIS TIME. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/AVIATION...BSS LONG TERM...FAB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
335 AM CDT FRI AUG 3 2012 .SHORT TERM /TODAY/... MOST IMMEDIATE CONCERN INVOLVES FATE OF SMALL MCS ALONG SD/NE BORDER. CLUSTER IS ELEVATED...MOST LIKELY ALONG 310K ISENT SURFACE...WITHIN STRONG MLCIN. RAP SUGGESTS MOISTURE TRANSPORT AND CONVERGENCE ALONG THIS SURFACE WILL MAINTAIN ITSELF TO OUR WEST WITH LITTLE MOVEMENT INTO THE MORNING SO WILL LEAVE OUR FORECAST DRY TODAY. RECENT UPSTREAM DEVELOPMENT SUPPORTS THIS SCENARIO AS WELL. NONE OF THE EXPLICIT OR PARAMETERIZED MODEL GUIDANCE SUGGESTS THIS WILL MAINTAIN ITSELF EASTWARD INTO IA EITHER. NEXT CONCERN WILL BE TEMPS. FORECAST SOUNDINGS AND LOW LEVEL TEMP CHANGE FROM YESTERDAY SUGGEST HIGHS MAY BE A FEW DEGREES WARMER WHICH MAKES SENSE AS LOW LEVEL WINDS SLOWLY VEER AND INCREASE SLIGHTLY. TRIMMING A FEW DEGREES OFF THE OFTEN OVERAGGRESSIVE TOO SUPER ADIABATIC NAM SUGGESTS HIGHS IN THE MID/UPPER 90S. LOWERING DEWPOINTS WITH MIXING THIS AFTERNOON WILL KEEP HEAT INDICES PLUS/MINUS A FEW DEGREES OF THE ACTUAL TEMPERATURE. .LONG TERM /TONIGHT THROUGH THURSDAY/... MODELS ARE A LITTLE SLOWER WITH THE SHORTWAVE TONIGHT ALSO THE BEST FORCING. AS A RESULT A BACKED OFF ON POPS THIS EVENING AND ON AREAL EXTENT OF POPS OVERNIGHT. UPPER TROUGH AND SURFACE COLD FRONT MOVE THROUGH MOST OF CENTRAL IOWA DURING THE MORNING INTO EARLY AFTERNOON. WHILE THE SYSTEM IS DYNAMIC...IT MOVES THROUGH MUCH OF THE CWA BEFORE PEAK HEATING SO THE BEST INSTABILITY WON/T BE REALIZED UNTIL THE SYSTEM IS MOSTLY EAST OF THE CWA. THE INTERESTING THING TO FORECAST FOR SATURDAY WILL BE TEMPS. SOUNDINGS SHOW THE DAYS HIGHS OCCURRING AROUND 18Z THEN BEGINNING TO FALL OFF. CLOUDS/PRECIP WILL IMPACT THE CWA AND THERE WILL LIKELY BE A PRETTY BIG THERMAL GRADIENT ACROSS THE STATE WITH MID 70S NORTHWEST AND MID 90S SOUTHEAST. SUNDAY WILL SEEM LIKE FALL WITH HIGHS IN THE 70S AND 80S. THIS WILL BE SHORT LIVED HOWEVER AS THE UPPER RIDGE REBUILDS OVER THE WEST EARLY NEXT WEEK. WHILE TEMPS ARE FORECAST TO WARM BACK UP INTO THE 80S AND 90S...IT WILL NOT BE AS WARM AS IT HAS BEEN. NUMEROUS SHORTWAVES WILL RIDE ATOP THE RIDGE ACROSS IOWA BUT TIMING AND STRENGTH OF THESE WAVES LEAVES THE POP FORECAST DIFFICULT AT BEST. MODELS DIFFER ON INTENSITY AND TIMING BUT IN THE TUESDAY NIGHT/WEDNESDAY TIMEFRAME ONE WAVE LOOKS LIKE IT WILL AFFECT THE WESTERN PORTION OF THE FORECAST AREA. ANOTHER STRONGER WAVE MOVES IN LATE IN THE EXTENDED...AROUND FRIDAY/FRIDAY NIGHT. POPS WERE HIT HARDEST DURING THIS TIME BUT WITH MODEL DISCREPANCIES AND WEAKER WAVES IN BETWEEN THE AFOREMENTIONED DAYS...I DID NOT FEEL SLIGHT POPS WERE WARRANTED. HOWEVER...AS RESOLUTION BECOMES BETTER...WE WILL LIKELY SEE OTHER PERIODS OF PRECIP DURING THE EXTENDED. && .AVIATION...03/06Z LOCALIZED SHOWERS AND THUNDERSTORMS STILL LINGERING OVER NORTHEAST IA. LOW POTENTIAL FOR THIS ACTIVITY TO REACH KALO AND IS NOT MENTIONED IN THE FORECAST. REMAINDER OF THE FORECAST WILL CONSIST OF LIGHT NORTHEAST TO EAST WINDS TONIGHT BECOMING SOUTHEAST ON FRIDAY UNDER VFR CONDITIONS. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...BSS LONG TERM...FAB AVIATION...BSS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1153 AM MDT FRI AUG 3 2012 .UPDATE... ISSUED AT 1145 AM MDT FRI AUG 3 2012 JUST COMPLETED ANOTHER UPDATE. MAIN THING WAS TO REFINE THE THUNDERSTORM AREA THIS AFTERNOON. RIGHT NOW IT LOOKS LIKE THE EASTERN PORTION OF THE FORECAST AREA MAY REMAIN CAPPED. HOWEVER...THERE IS AN OLD OUTFLOW BOUNDARY IN THAT AREA. SURFACE TROUGH HAS SET UP IN THE WESTERN PORTION OF THE AREA WHERE THE LEAST CAP IS. PLAN ON ADJUSTING TONIGHTS AND TOMORROWS PRECIPITATION. OTHERWISE TODAYS MAXES LOOK GOOD. UPDATE ISSUED AT 856 AM MDT FRI AUG 3 2012 JUST COMPLETED AN UPDATE. FIRST THING WAS TO ADJUST THE CLOUD COVER DOWN TO NEXT TO NOTHING THIS MORNING. MAIN CHANGE WAS FOR THE WINDS...MAINLY FOR TONIGHT AND TOMORROW. OUTFLOW BOUNDARY OR WEAK FRONT OVER THE EASTERN OF THE AREA SHOULD PULL AWAY. THE RUC AND NAM CATCHING THIS PLUS THE LOCATION OF THE INCOMING FRONT. RUC AND ESPECIALLY NAM WAS CATCHING THE SURFACE LOW AND TROUGH POSITION FROM WESTERN NEBRASKA INTO EASTERN COLORADO THE BEST AND WAS THE FARTHEST SOUTH WITH IT. SO WENT AHEAD AND ADJUSTED WINDS WITH THE NAM. NAM BRINGS THE FRONT IN A LITTLE FASTER AND CONSIDERING WHAT AM SEEING WITH THE INITIAL SURFACE AND UPPER AIR ANALYSIS THIS MORNING...THIS LOOKS VERY REASONABLE. FRONT PUSHES INTO THE EXTREME NORTHWEST PORTION OF THE AREA AT 06Z AND THEN THROUGH THE REST OF THE AREA BY 12Z. CONSIDERING THE COLD AIR AM SEEING WITH THIS SYSTEM...THE PRESSURE GRADIENT AND RATHER HIGH 3 HOUR PRESSURE RISES BEHIND...INCREASED THE WINDS BEHIND THE FRONT. COULD GET WINDY FOR A FEW HOURS BEHIND THE FRONT. AM GETTING MIXED SIGNALS ON WHERE THE THUNDERSTORMS ARE GOING TO DEVELOP THIS AFTERNOON. HRRR IS DEVELOPING STORMS IN THE FAR EAST WITH THE RUC AND NAM DEVELOPING STORMS NEAR THE TROUGH NEAR/OVER THE WESTERN PORTION OF OUR AREA. CURRENT GRIDS CAPTURE BOTH OF THESE SCENARIOS FOR AND WILL LEAVE AS IS FOR NOW. PLAN ON LEAVING MAXES AS IS FOR NOW AS WELL. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 200 AM MDT FRI AUG 3 2012 IT APPEARS THAT WEATHER DISTURBANCE CURRENTLY GENERATING THUNDERSTORMS IN NORTHERN NEW MEXICO WILL EMERGE OVER THE SOUTHERN PORTION OF THE FORECAST AREA BY NOON TODAY THEN INCREASE IN COVERAGE OVER AREAS GENERALLY EAST OF THE CO/KS BORDER BY THE END OF THE DAY. THIS AREA OF PRECIPITATION SHOULD MOVE EAST BY MIDNIGHT TONIGHT WITH ANOTHER CHANCE ACROSS THE AREA AFTER MIDNIGHT AS A COLD FRONT MOVES THROUGH. THIS AREA OF PRECIP WILL MOVE SOUTHEAST DURING THE DAY SATURDAY AND BY THE END OF THE DAY BE NEAR ARE SOUTHERN/SOUTHEASTERN FORECAST AREA OR SLIGHTLY OUTSIDE OF IT. SATURDAY NIGHT THROUGH SUNDAY NIGHT WILL BE DRY AS THE MOISTURE SOURCE AND ANY FORCING REMAIN SOUTH AND WEST OF THE AREA. HIGH TEMPERATURES TODAY IN THE 90S WITH AROUND 102 IN THE HILL CITY AREA. ON SATURDAY NOTICEABLY COOLER TEMPERATURES IN THE MID 70S NEAR FLAGLER TO MID 80S NEAR HILL CITY WITH GUSTY NORTH TO NORTHEAST WINDS. SLIGHTLY WARMER AND CLOSE TO NORMAL ON SUNDAY WITH UPPER 80S TO MID 90S. WITH HIGH PRESSURE OVERHEAD SATURDAY NIGHT LOW TEMPERATURES SHOULD DROP INTO THE LOW TO MID 50S. RECORD OR NEAR RECORD LOW TEMPERATURES ARE POSSIBLE IN HILL CITY (54 IN 1974)...YUMA (50)...AND COLBY (51). .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 200 AM MDT FRI AUG 3 2012 PRECIPITATION CHANCES RETURN TO THE AREA MONDAY NIGHT THROUGH WEDNESDAY NIGHT AS WEATHER DISTURBANCES WITHIN MONSOONAL MOISTURE MOVE ACROSS THE AREA. THURSDAY APPEARS TO BE DRY. HIGH TEMPERATURES THROUGH THE PERIOD GENERALLY IN THE 90S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1145 AM MDT FRI AUG 3 2012 LOOKS LIKE THUNDERSTORMS WILL NOT AFFECT EITHER TAF SITE UNTIL THE EVENING HOURS. WITH THE STORMS...IT LOOKS LIKE CONDITIONS WILL REMAIN VFR UNLESS A STRONG STORM COMES OVER THE TOP OF THEM. THESE STORMS WILL BE IN ADVANCE OF A STRONG COLD FRONT WHICH SHOULD LOOKS TO MOVE THROUGH BOTH SITES IN THE 06Z TO 08Z TIME FRAME WITH VERY GUSTY NORTHERLY WINDS EXPECTED. BEHIND THE FRONT IT IS LOOKING MORE LIKELY THAT MVFR CEILINGS WILL OCCUR. AFTER THE MAIN PUSH OF THE FRONT IS THROUGH PRECIPITATION AND CLOUDS SHOULD END QUICKLY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...99 LONG TERM...99 AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS WICHITA KS
1219 PM CDT FRI AUG 3 2012 .AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MCV OVER EASTERN KS WILL CONTINUE TO MOVE EASTWARD INTO MISSOURI LATER THIS AFTERNOON...WITH SHOWERS/T-STORMS DIMINISHING IN SOUTHEAST KS. FLOW WILL BECOME LIGHT SOUTH-SOUTHEASTERLY TONIGHT AHEAD OF APPROACHING COLD FRONT. ALTHOUGH MODELS WERE IN GOOD AGREEMENT ON FRONTAL TIMING...USED THE NAM FOR ITS STRONGER WIND GUSTS FROM NORTH BEHIND FROPA. FRONT SHOULD MOVE THROUGH CENTRAL KS SATURDAY MORNING...AND SOUTH CENTRAL AND SOUTHEAST KS SATURDAY PM/EVE. THUNDERSTORMS...AT LEAST A SCATTERED LINEAR COVERAGE...APPEAR POSSIBLE WITH THE FRONTAL PASSAGE PARTICULARLY SATURDAY PM/EVE AS STRONG HEATING DEVELOPS AHEAD OF IT. JMC && .PREV DISCUSSION... /ISSUED 659 AM CDT FRI AUG 3 2012/ AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MCV FROM EARLIER CONVECTION ACROSS WEST CENTRAL KANSAS CONTINUES TO SPIN OVER CENTRAL KANSAS BRINGING LIGHT RAIN SHOWERS TO KRSL AND KSLN. ADDITIONAL ACTIVITY WAS DEVELOPING OVER NORTHERN OKLAHOMA AND MAY DRIFT TOWARD KCNU DURING THE MORNING HOURS. EVEN WITH THE PRECIPITATION...VFR IS EXPECTED TO PREVAIL. WIND GUSTS HAVE DIMINISHED WITH LIGHT SOUTHEAST WINDS EXPECTED TO PREVAIL AS A WARM FRONT LIFTS NORTHWARD INTO SOUTHERN KANSAS THIS AFTERNOON. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY REDEVELOP ALONG AND NORTH OF THE FRONT THIS AFTERNOON AND TONIGHT. MWM PREV DISCUSSION... /ISSUED 322 AM CDT FRI AUG 3 2012/ DISCUSSION... MAIN FORECAST CHALLENGE WILL BE PRECIP TRENDS OVER THE NEXT 24 HOURS. SYNOPSIS: STRONG UPPER SHORTWAVE IS CURRENTLY APPROACHING THE NORTHERN ROCKIES. MEANWHILE WATER VAPOR IMAGERY SHOWS THE DIRTY MONSOONAL FLOW SPILLING MOISTURE OVER THE ROCKIES AND INTO THE HIGH PLAINS. AT THE SURFACE THE FRONT IS LOCATED FROM EXTREME SOUTHEAST KS TO NEAR ENID OK. TODAY-TONIGHT: STORMS DEVELOPED AROUND MIDNIGHT OVER SE KS IN AREA OF ISENTROPIC LIFT ALONG THE 315K SURFACE. THE STORMS THEN FILLED BACK TO THE WEST WHERE THE NAM SHOWED THE CAPPING THE WEAKEST ABOVE 850MB. MEANWHILE THE MCS THAT DEVELOPED OVER EASTERN CO THU EVENING IS STILL HOLDING TOGETHER AS IT PASSES JUST NORTH OF DDC. CURRENT THINKING IS THAT IT WILL FOLLOW THE WEAKEST CAPPING WHICH WOULD TAKE IT NORTH OF HIGHWAY 400. WHILE WE DO FEEL IT WILL EXHIBIT AN OVERALL DECREASE IN INTENSITY AND COVERAGE...DO THINK IT WILL AT LEAST HOLD TOGETHER LONG ENOUGH TO AFFECT THE WESTERN PORTION OF THE FORECAST AREA. EVEN IF THIS MCS DOES DIMINISH AS IT PASSES ACROSS THE FORECAST AREA...IT WILL STILL PLAY HAVOC WITH TEMPS AND THE TIMING OF THE FRONT. AT THIS POINT FEEL THE SHORT TERM MODELS MAYBE A BIT TOO AGGRESSIVE IN LIFTING THE FRONT NORTH TODAY. WILL THEREFORE BACK-OFF TEMPS A COUPLE DEGREES NORTH OF HIGHWAY 400. DO NOT HAVE ENOUGH CONFIDENCE TO ADD OR REMOVE COUNTIES FROM THE CURRENT HEADLINE...SO WILL LEAVE ALONE FOR NOW. THE COLD FRONT WILL START ITS JOURNEY ACROSS THE CENTRAL PLAINS TONIGHT. BUY MIDNIGHT IT IS EXPECTED TO STRETCH FROM EASTERN NEBRASKA INTO EXTREME NORTHWEST KS...WITH THIS FEATURE ENTERING THE NW FRINGES OF THE FORECAST AREA TOWARD SUNRISE. SCT CONVECTION SHOULD DEVELOP SOUTH OF THE FRONT OVER CENTRAL AND EASTERN KS AS MOISTURE TRANSPORT IN THE 850-700MB LEVEL INCREASES. SAT-SUN: BY SUNRISE SAT THE COLD FRONT IS EXPECTED TO STRETCH FROM NORTHEAST KS INTO WEST-CENTRAL KS. WITH LACK OF STRONG/DEEP CONVERGENCE ALONG THE FRONT...WOULD NOT BE SURPRISED TO SEE THE MORE WIDESPREAD PRECIP BEHIND THE FRONT WHERE THE BETTER UPPER DYNAMICS WILL BE SITUATED. WHILE CONFIDENCE IS HIGH THAT THERE WILL BE SOME SCATTERED ACTIVITY NEAR THE FRONT AS IT PUSHES SOUTH ON SAT...HAVE LOW CONFIDENCE ON HOW WIDESPREAD IT WILL BE. WITH SURFACE WINDS VEERING OUT AHEAD OF THE FRONT...FEEL TEMPS COULD REALLY SOAR ACROSS SOUTH CENTRAL AND ESPECIALLY SOUTHEAST KS. WOULD NOT BE SURPRISED TO SEE A FEW LOCATIONS PUSH 110-111 ALONG THE KS-OK BORDER. WILL LET THE DAY SHIFT MAKE THE CALL...BUT WOULD NOT BE SURPRISED IF THE CURRENT HEAT HEADLINE WOULD NEED TO BE EXTENDED ANOTHER DAY. BY SUNSET ON SAT THE FRONT SHOULD STRETCH ALONG THE KS-OK BORDER WITH SOME SHOWERS AND STORMS ALONG AND JUST BEHIND THE FRONT. CONFIDENCE IS HIGH THAT BY SUN MORNING THE PRECIP WILL BE SOUTH OF THE FORECAST AREA. MON-THU: THROUGH THESE EXTENDED PERIODS THE UPPER RIDGE IS EXPECTED TO SHIFT SLIGHTLY WEST WHICH WILL ALLOW THE FORECAST AREA TO REMAIN IN WEAK DIFFLUENCE ALOFT. IN ADDITION BOTH THE ECMWF AND GFS ARE TRACKING SOME SHORTWAVE ENERGY OUT OF THE NORTHERN ROCKIES AND ACROSS THE MISSOURI VALLEY ON TUE NIGHT THROUGH WED. WILL KEEP SOME SMALL PRECIP CHANCES FOR TUE NIGHT INTO WED WITH THE THINKING THAT THE BEST CHANCES WOULD BE CLOSER TO THE UPPER DYNAMICS OVER NORTHEAST KS. AS FAR AS TEMPS GO THROUGH THESE PERIODS...THEY WILL NOT BE AS EXTREME AS SOUTHERN KS HAS SEEN OVER THE LAST SEVERAL DAYS...BUT WILL STILL BE ABOVE NORMAL. LAWSON AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU BOUNDARY HAS STARTED ITS SLOW MIGRATION NORTHWARD EVIDENCED BY INCREASED THETA-E CONVERGENCE AND WINDS VEERING TO THE SOUTHEAST IN NORTHERN OKLAHOMA. FURTHER PROOF OF THIS IS THE SHOWERS WITH ISOLATED THUNDER FORMING OVER SOUTHEAST KANSAS AND BUILDING TOWARDS SOUTH CENTRAL KANSAS. LATEST HRRR GUIDANCE HAS THIS CONVECTION LINGERING FROM HUT TO ICT AND CNU THROUGH ABOUT 12-13Z. THE FOCUS SHIFTS TO FRIDAY AFTERNOON WHERE A VORT LOBE IS PROGGED TO MOVE OFF THE HIGH PLAINS. THIS MAY SPARK OFF SOME SHOWERS AND STORMS NEAR RSL AND SLN TOWARDS THE END OF THE TAF PERIOD. SINCE CONFIDENCE ON DEVELOPMENT AND TIMING ISN`T TOO GREAT...HAVE DECIDED TO LEAVE MENTION OF SHRA AND VCTS OUT FOR THOSE AREAS FOR THE MOMENT. ARL && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 102 79 100 69 / 30 20 30 40 HUTCHINSON 100 76 96 66 / 40 20 30 30 NEWTON 101 77 97 66 / 30 20 30 30 ELDORADO 102 78 99 68 / 40 20 30 40 WINFIELD-KWLD 106 80 106 71 / 40 20 30 40 RUSSELL 99 73 89 63 / 40 40 30 10 GREAT BEND 99 74 91 65 / 50 30 30 10 SALINA 100 75 91 64 / 50 30 30 20 MCPHERSON 100 75 95 65 / 50 20 30 20 COFFEYVILLE 108 80 106 71 / 50 10 20 40 CHANUTE 102 78 103 70 / 50 10 20 40 IOLA 101 78 101 69 / 50 10 20 40 PARSONS-KPPF 104 79 105 71 / 50 10 20 40 && .ICT WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 9 PM CDT THIS EVENING FOR KSZ069- 082-083-091>096-098>100. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
909 AM MDT FRI AUG 3 2012 .UPDATE... ISSUED AT 856 AM MDT FRI AUG 3 2012 JUST COMPLETED AN UPDATE. FIRST THING WAS TO ADJUST THE CLOUD COVER DOWN TO NEXT TO NOTHING THIS MORNING. MAIN CHANGE WAS FOR THE WINDS...MAINLY FOR TONIGHT AND TOMORROW. OUTFLOW BOUNDARY OR WEAK FRONT OVER THE EASTERN OF THE AREA SHOULD PULL AWAY. THE RUC AND NAM CATCHING THIS PLUS THE LOCATION OF THE INCOMING FRONT. RUC AND ESPECIALLY NAM WAS CATCHING THE SURFACE LOW AND TROUGH POSITION FROM WESTERN NEBRASKA INTO EASTERN COLORADO THE BEST AND WAS THE FARTHEST SOUTH WITH IT. SO WENT AHEAD AND ADJUSTED WINDS WITH THE NAM. NAM BRINGS THE FRONT IN A LITTLE FASTER AND CONSIDERING WHAT AM SEEING WITH THE INITIAL SURFACE AND UPPER AIR ANALYSIS THIS MORNING...THIS LOOKS VERY REASONABLE. FRONT PUSHES INTO THE EXTREME NORTHWEST PORTION OF THE AREA AT 06Z AND THEN THROUGH THE REST OF THE AREA BY 12Z. CONSIDERING THE COLD AIR AM SEEING WITH THIS SYSTEM...THE PRESSURE GRADIENT AND RATHER HIGH 3 HOUR PRESSURE RISES BEHIND...INCREASED THE WINDS BEHIND THE FRONT. COULD GET WINDY FOR A FEW HOURS BEHIND THE FRONT. AM GETTING MIXED SIGNALS ON WHERE THE THUNDERSTORMS ARE GOING TO DEVELOP THIS AFTERNOON. HRRR IS DEVELOPING STORMS IN THE FAR EAST WITH THE RUC AND NAM DEVELOPING STORMS NEAR THE TROUGH NEAR/OVER THE WESTERN PORTION OF OUR AREA. CURRENT GRIDS CAPTURE BOTH OF THESE SCENARIOS FOR AND WILL LEAVE AS IS FOR NOW. PLAN ON LEAVING MAXES AS IS FOR NOW AS WELL. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 200 AM MDT FRI AUG 3 2012 IT APPEARS THAT WEATHER DISTURBANCE CURRENTLY GENERATING THUNDERSTORMS IN NORTHERN NEW MEXICO WILL EMERGE OVER THE SOUTHERN PORTION OF THE FORECAST AREA BY NOON TODAY THEN INCREASE IN COVERAGE OVER AREAS GENERALLY EAST OF THE CO/KS BORDER BY THE END OF THE DAY. THIS AREA OF PRECIPITATION SHOULD MOVE EAST BY MIDNIGHT TONIGHT WITH ANOTHER CHANCE ACROSS THE AREA AFTER MIDNIGHT AS A COLD FRONT MOVES THROUGH. THIS AREA OF PRECIP WILL MOVE SOUTHEAST DURING THE DAY SATURDAY AND BY THE END OF THE DAY BE NEAR ARE SOUTHERN/SOUTHEASTERN FORECAST AREA OR SLIGHTLY OUTSIDE OF IT. SATURDAY NIGHT THROUGH SUNDAY NIGHT WILL BE DRY AS THE MOISTURE SOURCE AND ANY FORCING REMAIN SOUTH AND WEST OF THE AREA. HIGH TEMPERATURES TODAY IN THE 90S WITH AROUND 102 IN THE HILL CITY AREA. ON SATURDAY NOTICEABLY COOLER TEMPERATURES IN THE MID 70S NEAR FLAGLER TO MID 80S NEAR HILL CITY WITH GUSTY NORTH TO NORTHEAST WINDS. SLIGHTLY WARMER AND CLOSE TO NORMAL ON SUNDAY WITH UPPER 80S TO MID 90S. WITH HIGH PRESSURE OVERHEAD SATURDAY NIGHT LOW TEMPERATURES SHOULD DROP INTO THE LOW TO MID 50S. RECORD OR NEAR RECORD LOW TEMPERATURES ARE POSSIBLE IN HILL CITY (54 IN 1974)...YUMA (50)...AND COLBY (51). .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 200 AM MDT FRI AUG 3 2012 PRECIPITATION CHANCES RETURN TO THE AREA MONDAY NIGHT THROUGH WEDNESDAY NIGHT AS WEATHER DISTURBANCES WITHIN MONSOONAL MOISTURE MOVE ACROSS THE AREA. THURSDAY APPEARS TO BE DRY. HIGH TEMPERATURES THROUGH THE PERIOD GENERALLY IN THE 90S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 145 AM MDT FRI AUG 3 2012 VFR CONDITIONS EXPECTED AT KGLD THROUGH 00Z. FROM 00Z TO 12Z VFR PREVAILING BUT COULD DROP INTO MVFR RANGE FOR CIGS/VIS SHOULD A THUNDERSTORM MOVE OVER THE TERMINAL. AFTER 09Z MAY SEE SOME POST FRONTAL STRATUS AND REDUCED CIGS FOR A BRIEF PERIOD. TOO FAR OUT RIGHT NOW TO INCLUDE IN TAF. FOR KMCK VFR ALSO EXPECTED THROUGH THE DAY WITH INCREASING CHANCE TO LOWER INTO MVFR RANGE BY 00Z AND CONTINUING THROUGH 12Z AS THUNDERSTORM COVERAGE INCREASES OVER THE AREA. HERE TOO STRATUS MAY REDUCE CIGS IN THE 7-10Z TIMEFRAME. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...99 LONG TERM...99 AVIATION...99
AREA FORECAST DISCUSSION
NWS WICHITA KS
659 AM CDT FRI AUG 3 2012 .AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MCV FROM EARLIER CONVECTION ACROSS WEST CENTRAL KANSAS CONTINUES TO SPIN OVER CENTRAL KANSAS BRINGING LIGHT RAIN SHOWERS TO KRSL AND KSLN. ADDITIONAL ACTIVITY WAS DEVELOPING OVER NORTHERN OKLAHOMA AND MAY DRIFT TOWARD KCNU DURING THE MORNING HOURS. EVEN WITH THE PRECIPITATION...VFR IS EXPECTED TO PREVAIL. WIND GUSTS HAVE DIMINISHED WITH LIGHT SOUTHEAST WINDS EXPECTED TO PREVAIL AS A WARM FRONT LIFTS NORTHWARD INTO SOUTHERN KANSAS THIS AFTERNOON. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY REDEVELOP ALONG AND NORTH OF THE FRONT THIS AFTERNOON AND TONIGHT. MWM && .PREV DISCUSSION... /ISSUED 322 AM CDT FRI AUG 3 2012/ DISCUSSION... MAIN FORECAST CHALLENGE WILL BE PRECIP TRENDS OVER THE NEXT 24 HOURS. SYNOPSIS: STRONG UPPER SHORTWAVE IS CURRENTLY APPROACHING THE NORTHERN ROCKIES. MEANWHILE WATER VAPOR IMAGERY SHOWS THE DIRTY MONSOONAL FLOW SPILLING MOISTURE OVER THE ROCKIES AND INTO THE HIGH PLAINS. AT THE SURFACE THE FRONT IS LOCATED FROM EXTREME SOUTHEAST KS TO NEAR ENID OK. TODAY-TONIGHT: STORMS DEVELOPED AROUND MIDNIGHT OVER SE KS IN AREA OF ISENTROPIC LIFT ALONG THE 315K SURFACE. THE STORMS THEN FILLED BACK TO THE WEST WHERE THE NAM SHOWED THE CAPPING THE WEAKEST ABOVE 850MB. MEANWHILE THE MCS THAT DEVELOPED OVER EASTERN CO THU EVENING IS STILL HOLDING TOGETHER AS IT PASSES JUST NORTH OF DDC. CURRENT THINKING IS THAT IT WILL FOLLOW THE WEAKEST CAPPING WHICH WOULD TAKE IT NORTH OF HIGHWAY 400. WHILE WE DO FEEL IT WILL EXHIBIT AN OVERALL DECREASE IN INTENSITY AND COVERAGE...DO THINK IT WILL AT LEAST HOLD TOGETHER LONG ENOUGH TO AFFECT THE WESTERN PORTION OF THE FORECAST AREA. EVEN IF THIS MCS DOES DIMINISH AS IT PASSES ACROSS THE FORECAST AREA...IT WILL STILL PLAY HAVOC WITH TEMPS AND THE TIMING OF THE FRONT. AT THIS POINT FEEL THE SHORT TERM MODELS MAYBE A BIT TOO AGGRESSIVE IN LIFTING THE FRONT NORTH TODAY. WILL THEREFORE BACK-OFF TEMPS A COUPLE DEGREES NORTH OF HIGHWAY 400. DO NOT HAVE ENOUGH CONFIDENCE TO ADD OR REMOVE COUNTIES FROM THE CURRENT HEADLINE...SO WILL LEAVE ALONE FOR NOW. THE COLD FRONT WILL START ITS JOURNEY ACROSS THE CENTRAL PLAINS TONIGHT. BUY MIDNIGHT IT IS EXPECTED TO STRETCH FROM EASTERN NEBRASKA INTO EXTREME NORTHWEST KS...WITH THIS FEATURE ENTERING THE NW FRINGES OF THE FORECAST AREA TOWARD SUNRISE. SCT CONVECTION SHOULD DEVELOP SOUTH OF THE FRONT OVER CENTRAL AND EASTERN KS AS MOISTURE TRANSPORT IN THE 850-700MB LEVEL INCREASES. SAT-SUN: BY SUNRISE SAT THE COLD FRONT IS EXPECTED TO STRETCH FROM NORTHEAST KS INTO WEST-CENTRAL KS. WITH LACK OF STRONG/DEEP CONVERGENCE ALONG THE FRONT...WOULD NOT BE SURPRISED TO SEE THE MORE WIDESPREAD PRECIP BEHIND THE FRONT WHERE THE BETTER UPPER DYNAMICS WILL BE SITUATED. WHILE CONFIDENCE IS HIGH THAT THERE WILL BE SOME SCATTERED ACTIVITY NEAR THE FRONT AS IT PUSHES SOUTH ON SAT...HAVE LOW CONFIDENCE ON HOW WIDESPREAD IT WILL BE. WITH SURFACE WINDS VEERING OUT AHEAD OF THE FRONT...FEEL TEMPS COULD REALLY SOAR ACROSS SOUTH CENTRAL AND ESPECIALLY SOUTHEAST KS. WOULD NOT BE SURPRISED TO SEE A FEW LOCATIONS PUSH 110-111 ALONG THE KS-OK BORDER. WILL LET THE DAY SHIFT MAKE THE CALL...BUT WOULD NOT BE SURPRISED IF THE CURRENT HEAT HEADLINE WOULD NEED TO BE EXTENDED ANOTHER DAY. BY SUNSET ON SAT THE FRONT SHOULD STRETCH ALONG THE KS-OK BORDER WITH SOME SHOWERS AND STORMS ALONG AND JUST BEHIND THE FRONT. CONFIDENCE IS HIGH THAT BY SUN MORNING THE PRECIP WILL BE SOUTH OF THE FORECAST AREA. MON-THU: THROUGH THESE EXTENDED PERIODS THE UPPER RIDGE IS EXPECTED TO SHIFT SLIGHTLY WEST WHICH WILL ALLOW THE FORECAST AREA TO REMAIN IN WEAK DIFFLUENCE ALOFT. IN ADDITION BOTH THE ECMWF AND GFS ARE TRACKING SOME SHORTWAVE ENERGY OUT OF THE NORTHERN ROCKIES AND ACROSS THE MISSOURI VALLEY ON TUE NIGHT THROUGH WED. WILL KEEP SOME SMALL PRECIP CHANCES FOR TUE NIGHT INTO WED WITH THE THINKING THAT THE BEST CHANCES WOULD BE CLOSER TO THE UPPER DYNAMICS OVER NORTHEAST KS. AS FAR AS TEMPS GO THROUGH THESE PERIODS...THEY WILL NOT BE AS EXTREME AS SOUTHERN KS HAS SEEN OVER THE LAST SEVERAL DAYS...BUT WILL STILL BE ABOVE NORMAL. LAWSON AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU BOUNDARY HAS STARTED ITS SLOW MIGRATION NORTHWARD EVIDENCED BY INCREASED THETA-E CONVERGENCE AND WINDS VEERING TO THE SOUTHEAST IN NORTHERN OKLAHOMA. FURTHER PROOF OF THIS IS THE SHOWERS WITH ISOLATED THUNDER FORMING OVER SOUTHEAST KANSAS AND BUILDING TOWARDS SOUTH CENTRAL KANSAS. LATEST HRRR GUIDANCE HAS THIS CONVECTION LINGERING FROM HUT TO ICT AND CNU THROUGH ABOUT 12-13Z. THE FOCUS SHIFTS TO FRIDAY AFTERNOON WHERE A VORT LOBE IS PROGGED TO MOVE OFF THE HIGH PLAINS. THIS MAY SPARK OFF SOME SHOWERS AND STORMS NEAR RSL AND SLN TOWARDS THE END OF THE TAF PERIOD. SINCE CONFIDENCE ON DEVELOPMENT AND TIMING ISN`T TOO GREAT...HAVE DECIDED TO LEAVE MENTION OF SHRA AND VCTS OUT FOR THOSE AREAS FOR THE MOMENT. ARL && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 102 79 100 69 / 30 20 30 40 HUTCHINSON 100 76 96 66 / 40 20 30 30 NEWTON 101 77 97 66 / 30 20 30 30 ELDORADO 102 78 99 68 / 30 20 30 40 WINFIELD-KWLD 106 80 106 71 / 20 20 30 40 RUSSELL 99 73 89 63 / 40 40 30 10 GREAT BEND 99 74 91 65 / 50 30 30 10 SALINA 100 75 91 64 / 50 30 30 20 MCPHERSON 100 75 95 65 / 50 20 30 20 COFFEYVILLE 108 80 106 71 / 20 10 20 40 CHANUTE 102 78 103 70 / 30 10 20 40 IOLA 101 78 101 69 / 30 10 20 40 PARSONS-KPPF 104 79 105 71 / 20 10 20 40 && .ICT WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 9 PM CDT THIS EVENING FOR KSZ069- 082-083-091>096-098>100. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
358 AM CDT FRI AUG 3 2012 ...LONG TERM DISCUSSION UPDATED AT 358 AM... .SYNOPSIS... ISSUED AT 1000 PM CDT THU AUG 2 2012 THE 03.00Z 250 HPA SYNOPTIC MAP SHOWED THAT STRONGER JET FLOW WAS MAINLY CONFINED TO THE NORTHERN HALF OF THE UNITED STATES AND INTO CANADA. FLOW IN THIS REGION WAS GENERALLY GREATER THAN 50 KT. A FEW ~75 KT JET STREAKS WERE NOTED ACROSS BRITISH COLUMBIA, NORTHERN MICHIGAN, AND QUEBEC. ACROSS THE SOUTHERN HALF OF THE US, FLOW WAS GENERALLY LIGHT /15-30 KT/ WITH ANTICYCLONIC FLOW MOST PROMINENT ACROSS THE SOUTHERN PLAINS. AT 500 HPA, A STRONG 562 DM CYCLONE WITH COLD -20 DEG C TEMPS WAS LOCATED ACROSS CENTRAL ALBERTA. A SHORTWAVE TROUGH WAS MOVING ACROSS SOUTHEASTERN CANADA. A STRONG 595 DM ANTICYCLONE WAS DOMINATE OVER WEST TEXAS WITH RELATIVELY WARM /-5 TO -3 DEG C/ MID LEVEL TEMPERATURES. SOME MID LEVEL MOISTURE WAS ADVECTING TO THE NORTHEAST AROUND SAID HIGH. AT 700 HPA, THERE WAS ABOUT A 2 DEG C COOLING BETWEEN 00Z SYNOPTIC FLIGHTS ACROSS KDDC COUNTRY. STILL, 700 HPA TEMPERATURES WERE STILL FAIRLY WARM ACROSS THE CENTRAL AND SOUTHERN PLAINS WITH 13 TO 16 DEG C COMMONPLACE. THIS COOLING /ALTHOUGH SOMEWHAT MORE SIGNIFICANT/ WAS ALSO NOTED AT 850 HPA, ALTHOUGH TEMPS SOUTHWEST OF KDDC WERE STILL VERY WARM (IN THE 30S DEG C). AT THE SFC, A FRONTAL BOUNDARY WAS LOCATED ACROSS OKLAHOMA. ANOTHER FRONTAL SYSTEM WAS LOCATED ACROSS THE NORTHERN HIGH PLAINS. TROPICAL STORM ERNESTO WAS LOCATED NEAR 13.4N 58.3W AT 03.03Z. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 100 AM CDT FRI AUG 3 2012 THIS MORNING: FIRST CONCERN FOR THE SHORT TERM PERIOD IS OVERNIGHT CONVECTION. WAS FAIRLY LIBERAL WITH POPS GIVEN RADAR TRENDS AND THE LATEST FORECAST PROGRESSION FROM THE HRRR. THIS ACTIVITY WILL WEAKEN AS IT HEADS EAST ACROSS THE REGION. THERE SHOULD BE A FAIR AMOUNT OF CLOUD DEBRIS FROM THIS CONVECTION THROUGH THE NEXT 12 HOURS WHICH WILL HAVE IMPACTS ON HIGH TEMPERATURES LATER ON. TODAY: MONSOONAL MOISTURE IS WORKING ITS WAY AROUND THE STRONG MID LEVEL ANTICYCLONE TO OUR SOUTH. IN ADDITION, STRONGER FLOW ALOFT IS EXPECTED IN ASSOCIATION WITH THE PASSAGE OF A SHORTWAVE TROUGH WELL TO OUR NORTH. CURRENTLY THINK ANOTHER ROUND OF CONVECTION WILL BE LIKELY THIS AFTERNOON ACROSS THE REGION. HAVE THE HIGHEST (CHANCE POPS) ACROSS THE NORTHWEST ZONES WHERE BETTER LOW LEVEL CONVERGENCE AND UPPER LEVEL SUPPORT WILL BE. ALSO HAVE GONE WITH THE COOLER SIDE OF MOS GUIDANCE IN ANTICIPATION OF RESIDUAL CLOUD OVER FROM MORNING CONVECTION AND THEN ADDITIONAL CLOUD DEVELOPMENT THIS AFTERNOON. WOULD NOT COMPLETELY RULE OUT SEVERE WEATHER AS SBCAPE IS FORECAST TO BE AROUND 2000 J/KG AND 0-6 KM SHEAR FORECAST TO BE 30-40 KT. WITH 700-500 HPA LAPSE RATES AROUND 7 DEG/KM, CANNOT COMPLETELY RULE OUT AN ISOLATED SEVERE HAIL REPORT EITHER. TONIGHT: HAVE A CONCERN FOR OVERNIGHT CONVECTION AGAIN THIS EVENING BUT THE ACTIVITY SHOULD BE TRENDING DOWNWARD OVERNIGHT. PWATS DO CLIMB TO THE 75TH PERCENTILE SO THERE COULD BE HEAVY RAIN TONIGHT. MEANWHILE, AS THE AFOREMENTIONED UPPER LEVEL SHORTWAVE TROUGH TRAVERSES EAST, THIS WILL USHER IN A COLD FRONT BY SATURDAY MORNING. NORTHERLY WINDS MAY BECOME ON THE BREEZY SIDE AS 850 HPA WINDS INCREASE TO AROUND 20-30 KT IN THE WAKE OF THE FRONT. WILL GO WITH A BLEND OF THE 00Z NAM AND 00Z ALLBLEND WHICH HAS THE FRONT BISECTING THE REGION. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 356 AM CDT FRI AUG 3 2012 THE STRONG UPPER LEVEL CYCLONE SPINNING OVER SOUTHERN ALBERTA EARLY THIS MORNING WILL PROPAGATE EASTWARD ALONG THE CANADIAN BORDER INTO SOUTHEASTERN MANITOBA BY SATURDAY AFTERNOON. A COLD FRONT WILL MOVE ACROSS WESTERN KANSAS SATURDAY MORNING, AND TEMPERATURES ACTUALLY WILL BE BELOW CLIMATOLOGICAL AVERAGES THROUGH THE WEEKEND. THE PERSISTENT SUBTROPICAL ANTICYCLONE THAT HAS BEEN PARKED OVER THE CENTRAL AND SOUTHERN PLAINS WILL RETROGRADE TO THE SOUTHWESTERN PART OF THE COUNTRY EARLY NEXT WEEK BUT WILL BUILD BACK INTO THE CENTRAL PLAINS BY THURSDAY. THE ECMWF STILL DIGS A STRONGER TROUGH INTO THE GREAT LAKES MONDAY NIGHT AND TUESDAY THAN THE GFS AND CARRIES A WEAK COLD FRONT INTO NORTHERN KANSAS BY TUESDAY MORNING. THE GFS ALSO BUILDS THE UPPER LEVEL ANTICYCLONE BACK INTO THE PLAINS STRONGER THAN THE ECMWF LATE IN THE WEEK. MOST OF THE GEM ENSEMBLE MEMBERS SUPPORT A SOLUTION MORE SIMILAR TO THE GFS, AND THE GFS LARGELY WAS USED FOR GRID ADJUSTMENTS IN THE EXTENDED PERIOD. THERE LIKELY WILL BE ONGOING THUNDERSTORM ACTIVITY IN NORTHERN AND EASTERN KANSAS SATURDAY MORNING, AND OUTFLOW FROM THE CONVECTION PROBABLY WILL HAVE EFFECTED A SHIFT TO NORTH OR NORTHEAST WINDS ACROSS MUCH OF WESTERN KANSAS BEFORE THE ACTUAL COLD FRONT ARRIVES. MID LEVEL TEMPERATURES WILL BE WARM IN SOUTHWEST KANSAS, AND THERE LIKELY WILL BE LITTLE OPPORTUNITY FOR SURFACE BASED CONVECTION WITH THE COLD FRONT. FRONTOGENETIC FORCING IN THE BAROCLINIC ZONE BEHIND THE SURFACE FRONTAL POSITION ALONG WITH UPPER LEVEL DIVERGENCE IN THE ENTRANCE REGION OF THE UPPER LEVEL JET STREAK WITH THE NORTHERN PLAINS TROUGH WILL PRODUCE SYNOPTIC SCALE UPWARD VERTICAL MOTION OVER WESTERN KANSAS SATURDAY. POST FRONTAL SHOWERS AND THUNDERSTORMS LIKELY WILL PERSIST FOR MUCH OF THE DAY SATURDAY AND GRADUALLY WEAKEN BY SUNDAY EVENING AS THE BAROCLINICITY IN WESTERN KANSAS DIMINISHES. WITH CONSIDERABLE CLOUD COVER AND LOW LEVEL COLD AIR ADVECTION, TEMPERATURES WILL BE RELATIVELY COOL SATURDAY AND LIKELY WILL STRUGGLE TO REACH THE MID 80S IN WEST CENTRAL KANSAS. TEMPERATURES WILL APPROACH 100 DEGREES AGAIN IN BARBER COUNTY, WHERE COLD AIR ADVECTION WILL NOT BEGIN IN EARNEST UNTIL AFTERNOON. SUNDAY NIGHT WILL BE COOL IN NORTHERN KANSAS NEAR THE SURFACE ANTICYCLONE, BUT CLOUD COVER NEAR THE OKLAHOMA BORDER WILL KEEP TEMPERATURES RELATIVELY WARM. SHOWERS MAY PERSIST NEAR THE OKLAHOMA BORDER SATURDAY NIGHT BUT SHOULD END BEFORE SUNRISE SUNDAY. LOW LEVEL WINDS WILL RETURN TO THE SOUTH SUNDAY, AND TEMPERATURES WILL BE NEAR SEASONAL AVERAGES. WARM AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL SPREAD BACK INTO WESTERN KANSAS ON MONDAY, AND TEMPERATURES WILL WARM BACK INTO THE UPPER 90S IN MOST AREAS. AN UPPER LEVEL TROUGH EVIDENT ON SATELLITE IMAGERY NEAR 30N, 130W WILL MOVE AROUND THE WESTERN UNITED STATES ANTICYCLONE AND APPROACH THE CENTRAL PLAINS TUESDAY NIGHT AND WEDNESDAY. A DEEP BAROCLINIC ZONE WILL BE PRESENT IN THE CENTRAL PLAINS BETWEEN THE COOL HIGH PRESSURE IN THE MIDWEST AND VERY WARM AIR IN THE HIGHER TERRAIN OF COLORADO, AND SCATTERED THUNDERSTORMS MAY DEVELOP TUESDAY NIGHT AND CONTINUE WEDNESDAY AS THE UPPER LEVEL TROUGH RIPPLES DOWN THE BAROCLINC ZONE. ANTICYCLONIC FLOW ALOFT WILL BECOME MORE PRONOUNCED BY THURSDAY AS THE SUBTROPICAL HIGH BUILDS BACK INTO THE CENTRAL PART OF THE COUNTRY, AND HOT, DRY WEATHER WILL RETURN TO WESTERN KANSAS. THE UPPER LEVEL HIGH LIKELY WILL REMAIN ENTRENCHED IN THE CENTRAL PART OF THE COUNTRY UNTIL AT LEAST MID AUGUST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1200 AM CDT FRI AUG 3 2012 ATTENTION WAS PAID TO MAINLY TO THE FIRST 6 TO 9 HOURS OF THE TAF. FIRST CONCERN IS CONVECTION THROUGH THE OVERNIGHT HOURS AS AN MCS PROPAGATES EASTWARD ACROSS WESTERN KANSAS. HAVE USED RADAR TRENDS AND HRRR TO TIME CB/TS GROUPS FOR THE TAFS. CONVECTION WILL BE POSSIBLE AGAIN LATER IN THE TAF PERIOD, HOWEVER, WILL MAKE ADJUSTMENTS REGARDING OVERNIGHT CONVECTION AND LATER TAF ISSUANCE CAN MODIFY TAFS AS 12Z DATA COMES IN FOR CONVECTION LATER THIS AFTERNOON. GENERALLY CIGS SHOULD BE VFR THROUGH THE ENTIRE TAF PERIOD. E TO SE WINDS AROUND 10 KT EXPECTED AS WELL. && .PRELIMINARY POINT TEMPS/POPS... DDC 98 72 87 61 / 40 40 30 20 GCK 95 70 85 60 / 40 50 30 10 EHA 95 69 87 62 / 40 50 30 20 LBL 97 71 88 65 / 40 40 30 20 HYS 96 71 84 59 / 40 40 30 10 P28 104 76 93 70 / 30 30 20 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SUGDEN SHORT TERM...SUGDEN LONG TERM...RUTHI AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS WICHITA KS
322 AM CDT FRI AUG 3 2012 .DISCUSSION... MAIN FORECAST CHALLENGE WILL BE PRECIP TRENDS OVER THE NEXT 24 HOURS. SYNOPSIS: STRONG UPPER SHORTWAVE IS CURRENTLY APPROACHING THE NORTHERN ROCKIES. MEANWHILE WATER VAPOR IMAGERY SHOWS THE DIRTY MONSOONAL FLOW SPILLING MOISTURE OVER THE ROCKIES AND INTO THE HIGH PLAINS. AT THE SURFACE THE FRONT IS LOCATED FROM EXTREME SOUTHEAST KS TO NEAR ENID OK. TODAY-TONIGHT: STORMS DEVELOPED AROUND MIDNIGHT OVER SE KS IN AREA OF ISENTROPIC LIFT ALONG THE 315K SURFACE. THE STORMS THEN FILLED BACK TO THE WEST WHERE THE NAM SHOWED THE CAPPING THE WEAKEST ABOVE 850MB. MEANWHILE THE MCS THAT DEVELOPED OVER EASTERN CO THU EVENING IS STILL HOLDING TOGETHER AS IT PASSES JUST NORTH OF DDC. CURRENT THINKING IS THAT IT WILL FOLLOW THE WEAKEST CAPPING WHICH WOULD TAKE IT NORTH OF HIGHWAY 400. WHILE WE DO FEEL IT WILL EXHIBIT AN OVERALL DECREASE IN INTENSITY AND COVERAGE...DO THINK IT WILL AT LEAST HOLD TOGETHER LONG ENOUGH TO AFFECT THE WESTERN PORTION OF THE FORECAST AREA. EVEN IF THIS MCS DOES DIMINISH AS IT PASSES ACROSS THE FORECAST AREA...IT WILL STILL PLAY HAVOC WITH TEMPS AND THE TIMING OF THE FRONT. AT THIS POINT FEEL THE SHORT TERM MODELS MAYBE A BIT TOO AGGRESSIVE IN LIFTING THE FRONT NORTH TODAY. WILL THEREFORE BACK-OFF TEMPS A COUPLE DEGREES NORTH OF HIGHWAY 400. DO NOT HAVE ENOUGH CONFIDENCE TO ADD OR REMOVE COUNTIES FROM THE CURRENT HEADLINE...SO WILL LEAVE ALONE FOR NOW. THE COLD FRONT WILL START ITS JOURNEY ACROSS THE CENTRAL PLAINS TONIGHT. BUY MIDNIGHT IT IS EXPECTED TO STRETCH FROM EASTERN NEBRASKA INTO EXTREME NORTHWEST KS...WITH THIS FEATURE ENTERING THE NW FRINGES OF THE FORECAST AREA TOWARD SUNRISE. SCT CONVECTION SHOULD DEVELOP SOUTH OF THE FRONT OVER CENTRAL AND EASTERN KS AS MOISTURE TRANSPORT IN THE 850-700MB LEVEL INCREASES. SAT-SUN: BY SUNRISE SAT THE COLD FRONT IS EXPECTED TO STRETCH FROM NORTHEAST KS INTO WEST-CENTRAL KS. WITH LACK OF STRONG/DEEP CONVERGENCE ALONG THE FRONT...WOULD NOT BE SURPRISED TO SEE THE MORE WIDESPREAD PRECIP BEHIND THE FRONT WHERE THE BETTER UPPER DYNAMICS WILL BE SITUATED. WHILE CONFIDENCE IS HIGH THAT THERE WILL BE SOME SCATTERED ACTIVITY NEAR THE FRONT AS IT PUSHES SOUTH ON SAT...HAVE LOW CONFIDENCE ON HOW WIDESPREAD IT WILL BE. WITH SURFACE WINDS VEERING OUT AHEAD OF THE FRONT...FEEL TEMPS COULD REALLY SOAR ACROSS SOUTH CENTRAL AND ESPECIALLY SOUTHEAST KS. WOULD NOT BE SURPRISED TO SEE A FEW LOCATIONS PUSH 110-111 ALONG THE KS-OK BORDER. WILL LET THE DAY SHIFT MAKE THE CALL...BUT WOULD NOT BE SURPRISED IF THE CURRENT HEAT HEADLINE WOULD NEED TO BE EXTENDED ANOTHER DAY. BY SUNSET ON SAT THE FRONT SHOULD STRETCH ALONG THE KS-OK BORDER WITH SOME SHOWERS AND STORMS ALONG AND JUST BEHIND THE FRONT. CONFIDENCE IS HIGH THAT BY SUN MORNING THE PRECIP WILL BE SOUTH OF THE FORECAST AREA. MON-THU: THROUGH THESE EXTENDED PERIODS THE UPPER RIDGE IS EXPECTED TO SHIFT SLIGHTLY WEST WHICH WILL ALLOW THE FORECAST AREA TO REMAIN IN WEAK DIFFLUENCE ALOFT. IN ADDITION BOTH THE ECMWF AND GFS ARE TRACKING SOME SHORTWAVE ENERGY OUT OF THE NORTHERN ROCKIES AND ACROSS THE MISSOURI VALLEY ON TUE NIGHT THROUGH WED. WILL KEEP SOME SMALL PRECIP CHANCES FOR TUE NIGHT INTO WED WITH THE THINKING THAT THE BEST CHANCES WOULD BE CLOSER TO THE UPPER DYNAMICS OVER NORTHEAST KS. AS FAR AS TEMPS GO THROUGH THESE PERIODS...THEY WILL NOT BE AS EXTREME AS SOUTHERN KS HAS SEEN OVER THE LAST SEVERAL DAYS...BUT WILL STILL BE ABOVE NORMAL. LAWSON && .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU BOUNDARY HAS STARTED ITS SLOW MIGRATION NORTHWARD EVIDENCED BY INCREASED THETA-E CONVERGENCE AND WINDS VEERING TO THE SOUTHEAST IN NORTHERN OKLAHOMA. FURTHER PROOF OF THIS IS THE SHOWERS WITH ISOLATED THUNDER FORMING OVER SOUTHEAST KANSAS AND BUILDING TOWARDS SOUTH CENTRAL KANSAS. LATEST HRRR GUIDANCE HAS THIS CONVECTION LINGERING FROM HUT TO ICT AND CNU THROUGH ABOUT 12-13Z. THE FOCUS SHIFTS TO FRIDAY AFTERNOON WHERE A VORT LOBE IS PROGGED TO MOVE OFF THE HIGH PLAINS. THIS MAY SPARK OFF SOME SHOWERS AND STORMS NEAR RSL AND SLN TOWARDS THE END OF THE TAF PERIOD. SINCE CONFIDENCE ON DEVELOPMENT AND TIMING ISN`T TOO GREAT...HAVE DECIDED TO LEAVE MENTION OF SHRA AND VCTS OUT FOR THOSE AREAS FOR THE MOMENT. ARL && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 102 78 100 69 / 30 20 30 40 HUTCHINSON 100 76 96 66 / 40 20 30 30 NEWTON 101 77 97 66 / 30 20 30 30 ELDORADO 102 77 99 68 / 30 20 30 40 WINFIELD-KWLD 106 80 105 71 / 20 20 30 40 RUSSELL 98 73 90 63 / 40 40 30 10 GREAT BEND 99 74 92 65 / 50 30 30 10 SALINA 100 75 92 64 / 40 30 30 20 MCPHERSON 100 75 95 65 / 40 20 30 20 COFFEYVILLE 108 80 106 71 / 20 10 20 40 CHANUTE 102 78 103 70 / 30 10 20 40 IOLA 102 78 101 69 / 30 10 20 40 PARSONS-KPPF 104 79 105 71 / 30 10 20 40 && .ICT WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 9 PM CDT THIS EVENING FOR KSZ069- 082-083-091>096-098>100. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
100 AM CDT FRI AUG 3 2012 ...UPDATE TO SHORT TERM DISCUSSION... .SYNOPSIS... ISSUED AT 1000 PM CDT THU AUG 2 2012 THE 03.00Z 250 HPA SYNOPTIC MAP SHOWED THAT STRONGER JET FLOW WAS MAINLY CONFINED TO THE NORTHERN HALF OF THE UNITED STATES AND INTO CANADA. FLOW IN THIS REGION WAS GENERALLY GREATER THAN 50 KT. A FEW ~75 KT JET STREAKS WERE NOTED ACROSS BRITISH COLUMBIA, NORTHERN MICHIGAN, AND QUEBEC. ACROSS THE SOUTHERN HALF OF THE US, FLOW WAS GENERALLY LIGHT /15-30 KT/ WITH ANTICYCLONIC FLOW MOST PROMINENT ACROSS THE SOUTHERN PLAINS. AT 500 HPA, A STRONG 562 DM CYCLONE WITH COLD -20 DEG C TEMPS WAS LOCATED ACROSS CENTRAL ALBERTA. A SHORTWAVE TROUGH WAS MOVING ACROSS SOUTHEASTERN CANADA. A STRONG 595 DM ANTICYCLONE WAS DOMINATE OVER WEST TEXAS WITH RELATIVELY WARM /-5 TO -3 DEG C/ MID LEVEL TEMPERATURES. SOME MID LEVEL MOISTURE WAS ADVECTING TO THE NORTHEAST AROUND SAID HIGH. AT 700 HPA, THERE WAS ABOUT A 2 DEG C COOLING BETWEEN 00Z SYNOPTIC FLIGHTS ACROSS KDDC COUNTRY. STILL, 700 HPA TEMPERATURES WERE STILL FAIRLY WARM ACROSS THE CENTRAL AND SOUTHERN PLAINS WITH 13 TO 16 DEG C COMMONPLACE. THIS COOLING /ALTHOUGH SOMEWHAT MORE SIGNIFICANT/ WAS ALSO NOTED AT 850 HPA, ALTHOUGH TEMPS SOUTHWEST OF KDDC WERE STILL VERY WARM (IN THE 30S DEG C). AT THE SFC, A FRONTAL BOUNDARY WAS LOCATED ACROSS OKLAHOMA. ANOTHER FRONTAL SYSTEM WAS LOCATED ACROSS THE NORTHERN HIGH PLAINS. TROPICAL STORM ERNESTO WAS LOCATED NEAR 13.4N 58.3W AT 03.03Z. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 100 AM CDT FRI AUG 3 2012 THIS MORNING: FIRST CONCERN FOR THE SHORT TERM PERIOD IS OVERNIGHT CONVECTION. WAS FAIRLY LIBERAL WITH POPS GIVEN RADAR TRENDS AND THE LATEST FORECAST PROGRESSION FROM THE HRRR. THIS ACTIVITY WILL WEAKEN AS IT HEADS EAST ACROSS THE REGION. THERE SHOULD BE A FAIR AMOUNT OF CLOUD DEBRIS FROM THIS CONVECTION THROUGH THE NEXT 12 HOURS WHICH WILL HAVE IMPACTS ON HIGH TEMPERATURES LATER ON. TODAY: MONSOONAL MOISTURE IS WORKING ITS WAY AROUND THE STRONG MID LEVEL ANTICYCLONE TO OUR SOUTH. IN ADDITION, STRONGER FLOW ALOFT IS EXPECTED IN ASSOCIATION WITH THE PASSAGE OF A SHORTWAVE TROUGH WELL TO OUR NORTH. CURRENTLY THINK ANOTHER ROUND OF CONVECTION WILL BE LIKELY THIS AFTERNOON ACROSS THE REGION. HAVE THE HIGHEST (CHANCE POPS) ACROSS THE NORTHWEST ZONES WHERE BETTER LOW LEVEL CONVERGENCE AND UPPER LEVEL SUPPORT WILL BE. ALSO HAVE GONE WITH THE COOLER SIDE OF MOS GUIDANCE IN ANTICIPATION OF RESIDUAL CLOUD OVER FROM MORNING CONVECTION AND THEN ADDITIONAL CLOUD DEVELOPMENT THIS AFTERNOON. WOULD NOT COMPLETELY RULE OUT SEVERE WEATHER AS SBCAPE IS FORECAST TO BE AROUND 2000 J/KG AND 0-6 KM SHEAR FORECAST TO BE 30-40 KT. WITH 700-500 HPA LAPSE RATES AROUND 7 DEG/KM, CANNOT COMPLETELY RULE OUT AN ISOLATED SEVERE HAIL REPORT EITHER. TONIGHT: HAVE A CONCERN FOR OVERNIGHT CONVECTION AGAIN THIS EVENING BUT THE ACTIVITY SHOULD BE TRENDING DOWNWARD OVERNIGHT. PWATS DO CLIMB TO THE 75TH PERCENTILE SO THERE COULD BE HEAVY RAIN TONIGHT. MEANWHILE, AS THE AFOREMENTIONED UPPER LEVEL SHORTWAVE TROUGH TRAVERSES EAST, THIS WILL USHER IN A COLD FRONT BY SATURDAY MORNING. NORTHERLY WINDS MAY BECOME ON THE BREEZY SIDE AS 850 HPA WINDS INCREASE TO AROUND 20-30 KT IN THE WAKE OF THE FRONT. WILL GO WITH A BLEND OF THE 00Z NAM AND 00Z ALLBLEND WHICH HAS THE FRONT BISECTING THE REGION. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 234 PM CDT THU AUG 2 2012 NAM AND GFS INDICATING A 500MB VORT LOBE WILL EXIT COLORADO AND CROSS WESTERN KANSAS FRIDAY NIGHT. GIVEN LATE DAY INSTABILITY AND A SURFACE BOUNDARY IN/NEAR WESTERN KANSAS THERE STILL APPEARS TO BE AT LEAST A SLIGHT CHANCE FOR A SOME THUNDERSTORMS EARLY. BY SATURDAY MORNING THERE WILL BE ANOTHER CHANCE FOR THUNDERSTORMS AGAIN BEHIND A COLD FRONT AS SURGES SOUTH ACROSS WESTERN KANSAS. ALTHOUGH SOME TIMING ISSUES STILL EXIST WITH THE SURFACE FRONTAL PASSAGE...ALL THE MODELS TEND TO AGREE THAT THIS FRONT WILL UNDERCUT SOME WARM (+13 TO +15C) 700MB TEMPERATURES. AS A RESULT PRECIPITATION CHANCES WITH THE FRONT STILL APPEARS SMALL. THE BETTER OPPORTUNITY WILL BE POST FRONTAL BASED ON WHEN THE BETTER UPPER LEVEL DYNAMICS CROSS THE CENTRAL PLAINS. AS A RESULT BASED ON THE TIMING AND LOCATION OF AN UPPER LEVEL JET, AND MID LEVEL MOISTURE/FORCING WILL INCREASE PRECIPITATION CHANCES AFTER 12Z SATURDAY. PRECIPITATION SHOULD THEN BEGIN TO TAPER OFF FROM NORTHWEST TO SOUTHEAST EARLY SATURDAY NIGHT AS THE UPPER TROUGH CROSSES THE CENTRAL PLAINS AND BETTER MOISTURE NEAR THE 700MB BAROCLINIC ZONE EXITS WESTERN KANSAS. BY EARLY SUNDAY THE UPPER TROUGH WILL BEGIN TO MOVE INTO THE MISSISSIPPI VALLEY AS ANTICYCLONIC FLOW DEVELOPS ACROSS THE WESTERN ROCKIES AND A SURFACE HIGH SETTLES INTO THE CENTRAL PLAINS. BEHIND THIS COLD FRONT THE 850MB TEMPERATURES COOL FROM THE 30S AT 00Z SATURDAY TO THE 20S AT 00Z SUNDAY. 850MB TEMPERATURES REMAIN IN THE 20S AT 00Z SUNDAY AS THE SURFACE HIGH BUILDS ACROSS KANSAS. BASED ON THESE TEMPERATURE TRENDS AND THE EXPECTED POSSIBLE CLOUD COVER/PRECIPITATION BEHIND THIS FRONT ON SATURDAY THE PREVIOUS FORECAST STILL LOOKS REASONABLE. IF THE GFS VERIFIES IT MAY EVEN END UP BEING SLIGHTLY COOLER IN WEST CENTRAL AND NORTH CENTRAL KANSAS. ON SUNDAY THE HIGHS WILL BE SLIGHTLY WARMER, ESPECIALLY IN THE WEST BUT STILL BASED ON 00Z MONDAY 850MB MIX DOWN TEMPERATURES THE HIGHS ARE EXPECTED TO BE MAINLY IN THE 90S. EARLY NEXT WEEK AN AREA OF HIGH PRESSURE AT THE SURFACE WILL SLIDE EAST AND GIVE WAY TO A TROUGH OF LOW PRESSURE DEVELOPING ALONG THE LEE OF THE ROCKIES. THE UPPER LEVEL RIDGE AXIS WILL BE LOCATED NEAR THE ROCKIES WHICH WILL PLACE THE CENTRAL PLAINS IN A WEAK NORTHWEST FLOW. A WARMING TREND IS EXPECTED EARLY IN THE WORK WEEK BUT PRECIPITATION CHANCES AT LEAST THROUGH TUESDAY NIGHT STILL APPEARS SMALL WITH THE POSSIBLE EXCEPTION OF A FEW HIGH BASED CLOUDS/SHOWERS NEAR THE 700MB BAROCLINIC ZONE. A COLD FRONT MID WEEK WILL DROP SOUTH INTO CENTRAL KANSAS AS ANOTHER NORTHERN BRANCH UPPER LOW/TROUGH DROPS SOUTH OUT OF CANADA INTO THE GREAT LAKES. THIS WILL BRING ANOTHER BRIEF BREAK IN THE HEAT AS WELL AS A CHANCE FOR SCATTERED PRECIPITATION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1200 AM CDT FRI AUG 3 2012 ATTENTION WAS PAID TO MAINLY TO THE FIRST 6 TO 9 HOURS OF THE TAF. FIRST CONCERN IS CONVECTION THROUGH THE OVERNIGHT HOURS AS AN MCS PROPAGATES EASTWARD ACROSS WESTERN KANSAS. HAVE USED RADAR TRENDS AND HRRR TO TIME CB/TS GROUPS FOR THE TAFS. CONVECTION WILL BE POSSIBLE AGAIN LATER IN THE TAF PERIOD, HOWEVER, WILL MAKE ADJUSTMENTS REGARDING OVERNIGHT CONVECTION AND LATER TAF ISSUANCE CAN MODIFY TAFS AS 12Z DATA COMES IN FOR CONVECTION LATER THIS AFTERNOON. GENERALLY CIGS SHOULD BE VFR THROUGH THE ENTIRE TAF PERIOD. E TO SE WINDS AROUND 10 KT EXPECTED AS WELL. && .PRELIMINARY POINT TEMPS/POPS... DDC 72 93 63 92 / 40 40 20 10 GCK 70 88 62 91 / 50 30 20 10 EHA 69 88 64 91 / 50 40 30 10 LBL 71 92 67 92 / 40 40 30 10 HYS 71 90 61 92 / 40 40 10 0 P28 76 99 72 94 / 30 40 30 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SUGDEN SHORT TERM...SUGDEN LONG TERM...BURGERT AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1200 AM CDT FRI AUG 3 2012 ...UPDATE TO AVIATION FOR 06Z TAFS... .SYNOPSIS... ISSUED AT 1000 PM CDT THU AUG 2 2012 THE 03.00Z 250 HPA SYNOPTIC MAP SHOWED THAT STRONGER JET FLOW WAS MAINLY CONFINED TO THE NORTHERN HALF OF THE UNITED STATES AND INTO CANADA. FLOW IN THIS REGION WAS GENERALLY GREATER THAN 50 KT. A FEW ~75 KT JET STREAKS WERE NOTED ACROSS BRITISH COLUMBIA, NORTHERN MICHIGAN, AND QUEBEC. ACROSS THE SOUTHERN HALF OF THE US, FLOW WAS GENERALLY LIGHT /15-30 KT/ WITH ANTICYCLONIC FLOW MOST PROMINENT ACROSS THE SOUTHERN PLAINS. AT 500 HPA, A STRONG 562 DM CYCLONE WITH COLD -20 DEG C TEMPS WAS LOCATED ACROSS CENTRAL ALBERTA. A SHORTWAVE TROUGH WAS MOVING ACROSS SOUTHEASTERN CANADA. A STRONG 595 DM ANTICYCLONE WAS DOMINATE OVER WEST TEXAS WITH RELATIVELY WARM /-5 TO -3 DEG C/ MID LEVEL TEMPERATURES. SOME MID LEVEL MOISTURE WAS ADVECTING TO THE NORTHEAST AROUND SAID HIGH. AT 700 HPA, THERE WAS ABOUT A 2 DEG C COOLING BETWEEN 00Z SYNOPTIC FLIGHTS ACROSS KDDC COUNTRY. STILL, 700 HPA TEMPERATURES WERE STILL FAIRLY WARM ACROSS THE CENTRAL AND SOUTHERN PLAINS WITH 13 TO 16 DEG C COMMONPLACE. THIS COOLING /ALTHOUGH SOMEWHAT MORE SIGNIFICANT/ WAS ALSO NOTED AT 850 HPA, ALTHOUGH TEMPS SOUTHWEST OF KDDC WERE STILL VERY WARM (IN THE 30S DEG C). AT THE SFC, A FRONTAL BOUNDARY WAS LOCATED ACROSS OKLAHOMA. ANOTHER FRONTAL SYSTEM WAS LOCATED ACROSS THE NORTHERN HIGH PLAINS. TROPICAL STORM ERNESTO WAS LOCATED NEAR 13.4N 58.3W AT 03.03Z. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 353 PM CDT THU AUG 2 2012 AN UPPER LEVEL RIDGE AXIS REMAINED ACROSS THE SOUTHERN PLAINS TODAY AND WILL PERSIST THROUGH FRIDAY. OUTFLOW FROM OVERNIGHT CONVECTION PUSHED INTO OKLAHOMA TODAY AND REMAINED THERE. EASTERLY UPSLOPE FLOW RESULTED IN COOLER TEMPERATURES TODAY IN THE MID 90S TO AROUND 103F ACROSS SOUTHWEST KANSAS. A FEW THUNDERSTORMS COULD MOVE OUT OF COLORADO AND FAR WESTERN KANSAS ALONG THE INTERSTATE 70 CORRIDOR TONIGHT. THIS ACTIVITY IS NOT EXPECTED TO BE VERY WIDESPREAD IN THE ABSENCE OF ANY WELL DEFINED UPPER-LEVEL FEATURE. LOW LEVEL MOISTURE WILL GRADUALLY INCREASE ACROSS SOUTHWEST KANSAS THROUGH FRIDAY AS WEAK UPSLOPE FLOW CONTINUES TO THE NORTH OF A WEAK FRONTAL BOUNDARY. THIS WILL RESULT IN INCREASED SURFACE BASED CAPE VALUES TO AROUND 1000-1500 J/KG. MEANWHILE, A SHORTWAVE TROUGH WILL PASS ACROSS THE NORTHERN ROCKIES BY FRIDAY AFTERNOON, WITH INCREASING UPPER LEVEL FLOW AS FAR SOUTH AS KANSAS. WITH DAYTIME HEATING, INCREASING MOISTURE AND WEAK CAPPING, SOME AFTERNOON THUNDERSTORMS ARE POSSIBLE ONCE AGAIN. HIGHS MAY BE HELD DOWN A FEW DEGREES BY AFTERNOON CONVECTIVE INITIATION IN FAR WESTERN KANSAS AND THE RESULTANT CIRRIFORM BLOW OFF. NEVERTHELESS, TEMPERATURES SHOULD REACH AT LEAST AS HIGH AS TODAY`S NUMBERS. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 234 PM CDT THU AUG 2 2012 NAM AND GFS INDICATING A 500MB VORT LOBE WILL EXIT COLORADO AND CROSS WESTERN KANSAS FRIDAY NIGHT. GIVEN LATE DAY INSTABILITY AND A SURFACE BOUNDARY IN/NEAR WESTERN KANSAS THERE STILL APPEARS TO BE AT LEAST A SLIGHT CHANCE FOR A SOME THUNDERSTORMS EARLY. BY SATURDAY MORNING THERE WILL BE ANOTHER CHANCE FOR THUNDERSTORMS AGAIN BEHIND A COLD FRONT AS SURGES SOUTH ACROSS WESTERN KANSAS. ALTHOUGH SOME TIMING ISSUES STILL EXIST WITH THE SURFACE FRONTAL PASSAGE...ALL THE MODELS TEND TO AGREE THAT THIS FRONT WILL UNDERCUT SOME WARM (+13 TO +15C) 700MB TEMPERATURES. AS A RESULT PRECIPITATION CHANCES WITH THE FRONT STILL APPEARS SMALL. THE BETTER OPPORTUNITY WILL BE POST FRONTAL BASED ON WHEN THE BETTER UPPER LEVEL DYNAMICS CROSS THE CENTRAL PLAINS. AS A RESULT BASED ON THE TIMING AND LOCATION OF AN UPPER LEVEL JET, AND MID LEVEL MOISTURE/FORCING WILL INCREASE PRECIPITATION CHANCES AFTER 12Z SATURDAY. PRECIPITATION SHOULD THEN BEGIN TO TAPER OFF FROM NORTHWEST TO SOUTHEAST EARLY SATURDAY NIGHT AS THE UPPER TROUGH CROSSES THE CENTRAL PLAINS AND BETTER MOISTURE NEAR THE 700MB BAROCLINIC ZONE EXITS WESTERN KANSAS. BY EARLY SUNDAY THE UPPER TROUGH WILL BEGIN TO MOVE INTO THE MISSISSIPPI VALLEY AS ANTICYCLONIC FLOW DEVELOPS ACROSS THE WESTERN ROCKIES AND A SURFACE HIGH SETTLES INTO THE CENTRAL PLAINS. BEHIND THIS COLD FRONT THE 850MB TEMPERATURES COOL FROM THE 30S AT 00Z SATURDAY TO THE 20S AT 00Z SUNDAY. 850MB TEMPERATURES REMAIN IN THE 20S AT 00Z SUNDAY AS THE SURFACE HIGH BUILDS ACROSS KANSAS. BASED ON THESE TEMPERATURE TRENDS AND THE EXPECTED POSSIBLE CLOUD COVER/PRECIPITATION BEHIND THIS FRONT ON SATURDAY THE PREVIOUS FORECAST STILL LOOKS REASONABLE. IF THE GFS VERIFIES IT MAY EVEN END UP BEING SLIGHTLY COOLER IN WEST CENTRAL AND NORTH CENTRAL KANSAS. ON SUNDAY THE HIGHS WILL BE SLIGHTLY WARMER, ESPECIALLY IN THE WEST BUT STILL BASED ON 00Z MONDAY 850MB MIX DOWN TEMPERATURES THE HIGHS ARE EXPECTED TO BE MAINLY IN THE 90S. EARLY NEXT WEEK AN AREA OF HIGH PRESSURE AT THE SURFACE WILL SLIDE EAST AND GIVE WAY TO A TROUGH OF LOW PRESSURE DEVELOPING ALONG THE LEE OF THE ROCKIES. THE UPPER LEVEL RIDGE AXIS WILL BE LOCATED NEAR THE ROCKIES WHICH WILL PLACE THE CENTRAL PLAINS IN A WEAK NORTHWEST FLOW. A WARMING TREND IS EXPECTED EARLY IN THE WORK WEEK BUT PRECIPITATION CHANCES AT LEAST THROUGH TUESDAY NIGHT STILL APPEARS SMALL WITH THE POSSIBLE EXCEPTION OF A FEW HIGH BASED CLOUDS/SHOWERS NEAR THE 700MB BAROCLINIC ZONE. A COLD FRONT MID WEEK WILL DROP SOUTH INTO CENTRAL KANSAS AS ANOTHER NORTHERN BRANCH UPPER LOW/TROUGH DROPS SOUTH OUT OF CANADA INTO THE GREAT LAKES. THIS WILL BRING ANOTHER BRIEF BREAK IN THE HEAT AS WELL AS A CHANCE FOR SCATTERED PRECIPITATION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1200 AM CDT FRI AUG 3 2012 ATTENTION WAS PAID TO MAINLY TO THE FIRST 6 TO 9 HOURS OF THE TAF. FIRST CONCERN IS CONVECTION THROUGH THE OVERNIGHT HOURS AS AN MCS PROPAGATES EASTWARD ACROSS WESTERN KANSAS. HAVE USED RADAR TRENDS AND HRRR TO TIME CB/TS GROUPS FOR THE TAFS. CONVECTION WILL BE POSSIBLE AGAIN LATER IN THE TAF PERIOD, HOWEVER, WILL MAKE ADJUSTMENTS REGARDING OVERNIGHT CONVECTION AND LATER TAF ISSUANCE CAN MODIFY TAFS AS 12Z DATA COMES IN FOR CONVECTION LATER THIS AFTERNOON. GENERALLY CIGS SHOULD BE VFR THROUGH THE ENTIRE TAF PERIOD. E TO SE WINDS AROUND 10 KT EXPECTED AS WELL. && .PRELIMINARY POINT TEMPS/POPS... DDC 71 98 72 93 / 40 40 40 40 GCK 69 95 70 88 / 50 40 50 30 EHA 69 95 69 88 / 60 40 50 40 LBL 70 97 71 92 / 50 40 40 40 HYS 70 96 71 90 / 40 40 40 40 P28 75 104 76 99 / 30 30 30 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SUGDEN SHORT TERM...FINCH LONG TERM...BURGERT AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS WICHITA KS
1146 PM CDT THU AUG 2 2012 .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU BOUNDARY HAS STARTED ITS SLOW MIGRATION NORTHWARD EVIDENCED BY INCREASED THETA-E CONVERGENCE AND WINDS VEERING TO THE SOUTHEAST IN NORTHERN OKLAHOMA. FURTHER PROOF OF THIS IS THE SHOWERS WITH ISOLATED THUNDER FORMING OVER SOUTHEAST KANSAS AND BUILDING TOWARDS SOUTH CENTRAL KANSAS. LATEST HRRR GUIDANCE HAS THIS CONVECTION LINGERING FROM HUT TO ICT AND CNU THROUGH ABOUT 12-13Z. THE FOCUS SHIFTS TO FRIDAY AFTERNOON WHERE A VORT LOBE IS PROGGED TO MOVE OFF THE HIGH PLAINS. THIS MAY SPARK OFF SOME SHOWERS AND STORMS NEAR RSL AND SLN TOWARDS THE END OF THE TAF PERIOD. SINCE CONFIDENCE ON DEVELOPMENT AND TIMING ISN`T TOO GREAT...HAVE DECIDED TO LEAVE MENTION OF SHRA AND VCTS OUT FOR THOSE AREAS FOR THE MOMENT. && ARL .PREV DISCUSSION... /ISSUED 844 PM CDT THU AUG 2 2012/ UPDATE... TRENDED DOWN POPS A LITTLE BETWEEN NOW AND 6Z GIVEN RECENT RADAR AND SATELLITE TRENDS FOR AT LEAST THE CENTRAL PART OF THE CWA. BOUNDARY IS STILL LOCATED IN NORTHERN OKLAHOMA WITH SOME CU AND WIDELY SCATTERED STORMS DEVELOPING. THE BOUNDARY IS STILL PROGGED TO SLOWLY MOVE NORTH INTO SOUTHERN KANSAS THROUGHOUT TONIGHT. MOISTURE ADVECTION ISN`T VERY DESIRABLE AND A SIGNIFICANT SOURCE OF LIFT IS LACKING...BUT STILL CANNOT RULE OUT SOME HIT OR MISS ELEVATED SHOWERS ON THIS BOUNDARY DURING THE OVERNIGHT HOURS. ARL PREV DISCUSSION... /ISSUED 647 PM CDT THU AUG 2 2012/ AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MONSOONAL MOISTURE CONTINUES TO RIDE UP AND OVER THE RIDGE CENTERED OVER EASTERN NEW MEXICO AT THIS TIME. WIDELY SCATTERED STORMS ARE UNDERWAY OVER THE HIGH PLAINS AND ARE VERY SLOWLY DRIFING EAST. LATEST GUIDANCE KICKS OFF MORE CONVECTION ALONG LAST NIGHT`S OUTFLOW BOUNDARY/850MB BAROCLINIC ZONE...BUT KEEPS IT SOUTH OF THE OKLAHOMA BORDER FOR THE MOST PART. THIS IS CONFIRMED BY A LITTLE CU DEVELOPMENT OVER NORTHERN OKLAHOMA RIGHT NOW. ALSO...LATEST HRRR TENDS TO FIZZLE OUT THE CURRENT CONVECTION OVER WESTERN KANSAS...BUT BRINGS IN ANOTHER ROUND OVERNIGHT AROUND 9-12Z. CONFIDENCE IS STILL LOW...BUT A HINT OF A MID LEVEL WAVE ON WATER VAPOR MEANS SOME UPPER SUPPORT MAY ACCOMPANY THIS DEVELOPMENT...AND DECIDED TO ADD SOME VCSH TO RSL AND SLN FOR JUST A FEW PREDAWN HOURS. WILL CONTINUE TO MONITOR ONGOING CONVECTION TO OUR WEST AND DEVELOPMENT TO OUR SOUTH...AND WILL LOOK AT 00Z MODEL RUNS TO DETERMINE CHANCES FOR PRECIPITATION AT THE OTHER SITES OVERNIGHT. IN THE MEAN TIME VFR CONDITIONS WILL DOMINATE. ARL PREV DISCUSSION... /ISSUED 332 PM CDT THU AUG 2 2012/ DISCUSSION... TONIGHT...LIKE THE PAST FEW NIGHTS...CANNOT RULE OUT A FEW THUNDERSTORMS AFTER MIDNIGHT ACROSS THE REGION...AS WEAK MONSOONAL ENERGY TOPS STOUT UPPER RIDGE AND APPROACHES FROM THE WEST. WONDERING IF BETTER CHANCES TONIGHT WILL BE GENERALLY SOUTH OF I-70...ALONG/NORTH OF 850-700MB BOUNDARY...AND ALSO WITHIN HIGHEST PRECIPITABLE WATER AXIS. WIDESPREAD RELIEF APPEARS UNLIKELY...ALTHOUGH A FEW LOCATIONS COULD PICK UP A QUARTER INCH OR SO. FRIDAY TEMPERATURES...WITH THE POTENTIAL FOR ANOTHER OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION...TEMPERATURES WILL ONCE AGAIN BE TRICKY. HOWEVER...DO THINK AT LEAST SOUTHERN KANSAS TEMPERATURES WILL SOAR WELL INTO THE 100S...SO WENT AHEAD AND EXTENDED CURRENT EXCESSIVE HEAT WARNING THROUGH FRIDAY GENERALLY SOUTH OF HIGHWAY 54. DEPENDING ON HOW CONVECTION EVOLVES TONIGHT...NIGHT SHIFT MAY NEED TO EXTEND THIS HEADLINE A TAD FURTHER NORTH. FRIDAY-SATURDAY...A FEW SHOWERS/THUNDERSTORMS MAY LINGER OVER THE AREA INTO THE FRIDAY MORNING HOURS. OTHERWISE...WITH BOUNDARY REMAINING IN PLACE...CANNOT RULE OUT A STRAY LATE AFTERNOON/EVENING THUNDERSTORM OVER FAR SOUTHERN KS. SOMEWHAT BETTER CHANCES MAY ARRIVE LATE FRIDAY NIGHT OVER CENTRAL KS...AS A STRONG COLD FRONT APPROACHES FROM THE NORTHWEST. THE BEST THUNDERSTORM CHANCES SHOULD BE ALONG THE COLD FRONT SATURDAY AFTERNOON-NIGHT OVER MAINLY SOUTHERN KANSAS. DESPITE MARGINAL INSTABILITY AND BEST UPPER FORCING REMAINING NORTH OF THE REGION...THINKING FRONTAL FORCING WILL BE ENOUGH FOR AT LEAST WIDELY SCATTERED STORMS. PROBABLY NOT A WIDESPREAD HEAVY RAINFALL EVENT...BUT PROBABLY AT LEAST SOME MODEST RELIEF. WIDESPREAD SEVERE WEATHER APPEARS UNLIKELY...ALTHOUGH ISOLATED STRONG/SEVERE WILL BE POSSIBLE. SUNDAY...MODEST TEMPERATURE RELIEF IN WAKE OF THE COLD FRONT EXPECTED...WITH HIGHS IN THE 90S ALL AREAS. MONDAY-THURSDAY...MEDIUM RANGE GUIDANCE AND ASSOCIATED GFS ENSEMBLES SUGGEST UPPER RIDGE WILL RETROGRADE WEST A BIT FOR NEXT WEEK KEEPING NORTHWEST FLOW ALOFT ACROSS THE REGION. CONSEQUENTLY...WHILE ABOVE NORMAL TEMPERATURES ARE STILL ANTICIPATED...CONFIDENCE IS INCREASING THAT NEXT WEEK WILL ONLY BE IN THE 90S TO MAYBE LOW 100S. ADDITIONALLY...NORTHWEST FLOW ALOFT BODES WELL FOR PERIODIC PRECIPITATION CHANCES...AS AFTERNOON WESTERN HIGH PLAINS THUNDERSTORM ACTIVITY ROLLS SOUTHEAST ALONG EASTERN EDGE OF WARM 850-700MB THERMAL RIDGE DURING THE EVENING AND NIGHTTIME HOURS. HOWEVER...LEFT FORECAST DRY FOR NOW TO WAIT FOR BETTER RUN-TO-RUN CONSISTENCY. KLEINSASSER AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU WEAK PV ANOMALY WILL CONTINUE MOVING SLOWLY EASTWARD ACROSS SOUTH CENTRAL/SOUTHEAST KS THIS AFTERNOON. THIS SHOULD ALLOW FOR ISOLATED-WIDELY SCATTERED HIGH-BASED -SHRA/-TSRA TO PERSIST THIS AFTERNOON. WILL MENTION VCSH AT HUT/ICT/SLN BASED ON LATEST RADAR TRENDS. THERE WILL BE A SMALL CHANCE OF HIGH-BASED -TSRA TONIGHT INTO FRIDAY MORNING ACROSS THE AREA...WITH HIGH PRECIPITABLE WATER AXIS REMAINING ALONG WITH WEAKNESS AT 700 MB. CHANCES APPEAR TOO LOW TO MENTION AT TAF SITES THIS FAR OUT ESPECIALLY GIVEN COVERAGE CONCERNS. GUSTY WINDS POSSIBLE NEAR ANY STORM ACTIVITY GIVEN TEMPERATURE-DEWPOINT SPREADS. OTHERWISE VFR TO PREVAIL. JMC && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 105 76 105 78 / 20 30 10 10 HUTCHINSON 103 74 103 76 / 20 30 10 20 NEWTON 103 74 103 77 / 20 30 10 10 ELDORADO 103 74 104 78 / 20 30 10 10 WINFIELD-KWLD 109 78 107 80 / 20 30 10 10 RUSSELL 98 73 102 73 / 20 30 10 30 GREAT BEND 100 73 102 74 / 20 30 10 30 SALINA 98 73 102 75 / 20 30 10 30 MCPHERSON 101 73 103 76 / 20 30 10 20 COFFEYVILLE 110 77 107 79 / 20 30 10 10 CHANUTE 105 74 103 79 / 20 30 10 10 IOLA 103 75 102 79 / 20 30 10 10 PARSONS-KPPF 107 75 105 79 / 20 30 10 10 && .ICT WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 9 PM CDT FRIDAY FOR KSZ069-082-083- 091>096-098>100. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
653 PM EDT FRI AUG 3 2012 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA THIS EVENING AND MOST OFF THE COAST OVERNIGHT. HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... 7PM UPDATE...UPDATED POP/WX/SKY FOR LATEST RADAR/SATELLITE TRENDS. ACTIVITY WILL CONTINUE TO DECREASE IN COVERAGE AND OVERALL INTENSITY AS THE SUN CONTINUES TO SET. PREV DISCUSSION... CHALLENGES WILL ARE CONVECTION THIS AFTERNOON INTO THE EVENING AND HOW STRONG AND HOW EXTENSIVE WILL THE FOG BE. TSTMS FIRING ACROSS NORTHERN AND CENTRAL AREAS ATTM AHEAD OF THE APCHG COLD FRONT. STILL EXPECTING CONVECTION TO FIRE UP ACROSS PORTIONS OF THE CENTRAL HIGHLANDS AND DOWNEAST REGIONS LATER THIS AFTERNOON AS BEST INSTABILITY SHIFTS SSE. SPC MESO-ANALYSIS INDICATES THIS ATTM. ALSO, THINKING HEAVY RAINFALL AND STRONG WIND GUSTS STILL POSSIBLE. SBCAPES UP AROUND 2000+ JOULES W/LIS DOWN TO AROUND -5. 0-6KM SHEAR FROM THE LATEST RUC WAS AROUND 25KTS WHICH WOULD FAVOR POSSIBLE DOWNBURST WINDS. EXPECTING CONVECTION TO WIND DOWN THIS EVENING AS INSTABILITY AXIS SHIFTS EAST INTO NEW BRUNSWICK. COLD FRONT WILL CLEAR THE COAST TONIGHT W /DRIER-COOLER AIR EXPECTED TO FILTER BEHIND THE FRONT. MIDNIGHT CREW/S OVERNIGHT MINS OF LOW/MID 50S ACROSS THE NORTH W /MID-UPPER 50S CENTRAL AND DOWNEAST LOOKED GOOD. THE OTHER CONCERN IS FOG RETURNING OVERNIGHT INTO SATURDAY MORNING. DECIDED ON AREAS OF FOG RIGHT ALONG THE IMMEDIATE COAST AND OVER THE WATERS. FURTHER INLAND, WENT W/PATCHY FOG FOR NOW GIVEN THE DRYING TREND. THERE COULD BE A BRIEF TIME WHEN VSBYS DROP LOWER AS DEWPOINT ALIGNS W/THE TEMPERATURE. THIS WILL BE ESPECIALLY TRUE IN AREAS FROM EARLIER RAINFALL. HIGH PRES BUILDING INTO THE REGION FROM CANADA ON SATURDAY WILL PROVIDE DRY AND PLEASANT CONDITIONS FOR EARLY AUGUST. MAX TEMPERATURES SHOULD HAVE NO PROBLEM REACHING WELL INTO THE 80S W/AMPLE SUNSHINE. LATEST MOS/NAM MAXES MATCHED CLOSE TO WHAT THE MIDNIGHT CREW HAS AND THEREFORE ONLY TWEAKING WAS DONE FOR THE COAST TO BRING MAXES UP DUE TO OFFSHORE WINDS. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... A WARM FRONT WILL LIFT NORTH THROUGH THE REGION SATURDAY NIGHT INTO SUNDAY USHERING IN VERY WARM AND HUMID CONDITIONS. EXPECT HIGHS SUNDAY GENERALLY IN THE MID 80S WITH DEW POINTS RISING INTO THE MID TO HIGH 60S. WINDS WILL BE GUSTY OUT OF THE SOUTH AND THIS WILL HELP TO KEEP TEMPERATURES COOLER ALONG THE COAST WHERE HIGHS WILL BE IN THE 70S. CLOUDS WILL INCREASE IN THE AFTERNOON AHEAD OF AN APPROACHING COLD FRONT BUT ANY SHOWER/THUNDERSTORM ACTIVITY LOOKS TO REMAIN WEST OF THE REGION THROUGH THE DAY. AS THE COLD FRONT CONTINUES TO ADVANCE SUNDAY NIGHT SHOWERS WITH POSSIBLE THUNDERSTORMS WILL ROLL THROUGH FROM WEST TO EAST AHEAD OF FRONT DURING THE LATE EVENING INTO THE OVERNIGHT. INSTABILITY LOOKS TO BE MARGINAL DUE TO THE TIMING OF THE FRONT BEING AT NIGHT AND AS A RESULT ANY CONVECTION THAT OCCURS DOES NOT LOOK TO BE SEVERE, ALTHOUGH SOME HEAVY DOWNPOURS WILL BE POSSIBLE. BY MONDAY MORNING THE FRONT LOOKS TO BE SITUATED CLOSE TO THE WESTERN EDGE OF THE STATE. SHOWERS AND STORMS WILL CLEAR THE AREA FROM WEST TO EAST THROUGH THE DAY AS THE FRONT ADVANCES EAST. THE BEST CHANCE FOR ANY STRONGER STORMS MONDAY WILL BE DOWNEAST AS THAT AREA WILL BE LAST TO CLEAR DURING THE AFTERNOON. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ZONAL FLOW WILL DEVELOP BEHIND AN EXITING COLD FRONT MONDAY NIGHT. DRY WEATHER IS EXPECTED IN THE WAKE OF THIS FRONT THROUGH TUESDAY NIGHT. THE PERSISTENT SUMMER 2012 UPPER TROUGH RETURNS WEDNESDAY THROUGH FRIDAY. ANTICIPATE A CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS DAYS 5 THROUGH 7 WITH DISTURBANCES ROTATING AROUND THE BASE OF THE TROUGH. TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: VFR W/TEMPO MVFR THIS AFTERNOON INTO THE EVENING W/TSTMS FIRING. LEANED W/MVFR VSBY LATER TONIGHT INTO SATURDAY MORNING FOR THE NORTHERN TERMINALS WHILE KBGR AND KBHB ARE EXPECTED TO DROP TO IFR BY 09Z SATURDAY. AFTER 12Z SATURDAY, LOOKS LIKE VFR. SHORT TERM: LOOKS LIKE VFR SATURDAY NIGHT INTO SUNDAY FOR THE MOST PART. HOWEVER, MVFR AND IFR POSSIBLE ACROSS KBGR AND KBHB COULD BE SEEN EARLY SUNDAY MORNING AS WINDS BECOME SOUTHERLY AHEAD OF AN APPROACHING COLD FRONT. SUNDAY NIGHT INTO MONDAY COULD BE INTERESTING AS THAT STRONGER COLD FRONT MOVES ACROSS THE REGION W/POSSIBLE TSTMS AND WIND AND MVFR/IFR CONDITIONS. && .MARINE... NEAR TERM: NO HEADLINES. MAIN CHALLEGE WILL THE CONTINUING 4-5 FOOT SWELL WHICH IS OUT THERE ATTM. WINDS WILL INCREASE SOME OVERNIGHT W/THE COLD FROPA, BUT WINDS WILL RELAX ON SATURDAY AS HIGH PRES MOVES IN FROM CANADA. AREAS OF FOG WILL BE NUISANCE OVERNIGHT BUT VSBYS SHOULD IMPROVE LATER SATURDAY MORNING. USED THE NAM12 AND GFS FOR THE WINDS WHICH SUPPORT 10-15 KTS TONIGHT AND THEN SPEEDS FROP OFF FOR SATURDAY. BROUGHT THE SWELL DOWN TO 3 FT BY MIDDAY SATURDAY W/AN OFFSHORE FLOW. SHORT TERM: POSSIBLE SCA FOR SUNDAY NIGHT INTO MONDAY AS PRES GRADIENT TIGHTEN AHEAD AND W/THE FRONTAL PASSAGE. WINDS START COMING DOWN LATER MONDAY INTO TUESDAY. BACKED OFF A BIT ON THE WNAWAVE BY DROPPING THEM BACK 1-2 FEET. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT/NRR SHORT TERM...FITZSIMMONS LONG TERM...OKULSKI AVIATION...HEWITT MARINE...HEWITT/FITZSIMMONS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
317 PM EDT FRI AUG 3 2012 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA THIS EVENING AND MOST OFF THE COAST OVERNIGHT. HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... CHALLENGES WILL CONVECTION THIS AFTERNOON INTO THE EVENING AND HOW STRONG AND HOW EXTENSIVE WILL THE FOG BE. TSTMS FIRING ACROSS NORTHERN AND CENTRAL AREAS ATTM AHEAD OF THE APCHG COLD FRONT. STILL EXPECTING CONVECTION TO FIRE UP ACROSS PORTIONS OF THE CENTRAL HIGHLANDS AND DOWNEAST REGIONS LATER THIS AFTERNOON AS BEST INSTABILITY SHIFTS SSE. SPC MESO-ANALYSIS INDICATES THIS ATTM. ALSO, THINKING HEAVY RAINFALL AND STRONG WIND GUSTS STILL POSSIBLE. SBCAPES UP AROUND 2000+ JOULES W/LIS DOWN TO AROUND -5. 0-6KM SHEAR FROM THE LATEST RUC WAS AROUND 25KTS WHICH WOULD FAVOR POSSIBLE DOWNBURST WINDS. EXPECTING CONVECTION TO WIND DOWN THIS EVENING AS INSTABILITY AXIS SHIFTS EAST INTO NEW BRUNSWICK. COLD FRONT WILL CLEAR THE COAST TONIGHT W /DRIER-COOLER AIR EXPECTED TO FILTER BEHIND THE FRONT. MIDNIGHT CREW/S OVERNIGHT MINS OF LOW/MID 50S ACROSS THE NORTH W /MID-UPPER 50S CENTRAL AND DOWNEAST LOOKED GOOD. THE OTHER CONCERN IS FOG RETURNING OVERNIGHT INTO SATURDAY MORNING. DECIDED ON AREAS OF FOG RIGHT ALONG THE IMMEDIATE COAST AND OVER THE WATERS. FURTHER INLAND, WENT W/PATCHY FOG FOR NOW GIVEN THE DRYING TREND. THERE COULD BE A BRIEF TIME WHEN VSBYS DROP LOWER AS DEWPOINT ALIGNS W/THE TEMPERATURE. THIS WILL BE ESPECIALLY TRUE IN AREAS FROM EARLIER RAINFALL. HIGH PRES BUILDING INTO THE REGION FROM CANADA ON SATURDAY WILL PROVIDE DRY AND PLEASANT CONDITIONS FOR EARLY AUGUST. MAX TEMPERATURES SHOULD HAVE NO PROBLEM REACHING WELL INTO THE 80S W/AMPLE SUNSHINE. LATEST MOS/NAM MAXES MATCHED CLOSE TO WHAT THE MIDNIGHT CREW HAS AND THEREFORE ONLY TWEAKING WAS DONE FOR THE COAST TO BRING MAXES UP DUE TO OFFSHORE WINDS. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... A WARM FRONT WILL LIFT NORTH THROUGH THE REGION SATURDAY NIGHT INTO SUNDAY USHERING IN VERY WARM AND HUMID CONDITIONS. EXPECT HIGHS SUNDAY GENERALLY IN THE MID 80S WITH DEW POINTS RISING INTO THE MID TO HIGH 60S. WINDS WILL BE GUSTY OUT OF THE SOUTH AND THIS WILL HELP TO KEEP TEMPERATURES COOLER ALONG THE COAST WHERE HIGHS WILL BE IN THE 70S. CLOUDS WILL INCREASE IN THE AFTERNOON AHEAD OF AN APPROACHING COLD FRONT BUT ANY SHOWER/THUNDERSTORM ACTIVITY LOOKS TO REMAIN WEST OF THE REGION THROUGH THE DAY. AS THE COLD FRONT CONTINUES TO ADVANCE SUNDAY NIGHT SHOWERS WITH POSSIBLE THUNDERSTORMS WILL ROLL THROUGH FROM WEST TO EAST AHEAD OF FRONT DURING THE LATE EVENING INTO THE OVERNIGHT. INSTABILITY LOOKS TO BE MARGINAL DUE TO THE TIMING OF THE FRONT BEING AT NIGHT AND AS A RESULT ANY CONVECTION THAT OCCURS DOES NOT LOOK TO BE SEVERE, ALTHOUGH SOME HEAVY DOWNPOURS WILL BE POSSIBLE. BY MONDAY MORNING THE FRONT LOOKS TO BE SITUATED CLOSE TO THE WESTERN EDGE OF THE STATE. SHOWERS AND STORMS WILL CLEAR THE AREA FROM WEST TO EAST THROUGH THE DAY AS THE FRONT ADVANCES EAST. THE BEST CHANCE FOR ANY STRONGER STORMS MONDAY WILL BE DOWNEAST AS THAT AREA WILL BE LAST TO CLEAR DURING THE AFTERNOON. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ZONAL FLOW WILL DEVELOP BEHIND AN EXITING COLD FRONT MONDAY NIGHT. DRY WEATHER IS EXPECTED IN THE WAKE OF THIS FRONT THROUGH TUESDAY NIGHT. THE PERSISTENT SUMMER 2012 UPPER TROUGH RETURNS WEDNESDAY THROUGH FRIDAY. ANTICIPATE A CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS DAYS 5 THROUGH 7 WITH DISTURBANCES ROTATING AROUND THE BASE OF THE TROUGH. TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... NEAR TERM: VFR W/TEMPO MVFR THIS AFTERNOON INTO THE EVENING W/TSTMS FIRING. LEANED W/MVFR VSBY LATER TONIGHT INTO SATURDAY MORNING FOR THE NORTHERN TERMINALS WHILE KBGR AND KBHB ARE EXPECTED TO DROP TO IFR BY 09Z SATURDAY. AFTER 12Z SATURDAY, LOOKS LIKE VFR. SHORT TERM: LOOKS LIKE VFR SATURDAY NIGHT INTO SUNDAY FOR THE MOST PART. HOWEVER, MVFR AND IFR POSSIBLE ACROSS KBGR AND KBHB COULD BE SEEN EARLY SUNDAY MORNING AS WINDS BECOME SOUTHERLY AHEAD OF AN APPROACHING COLD FRONT. SUNDAY NIGHT INTO MONDAY COULD BE INTERESTING AS THAT STRONGER COLD FRONT MOVES ACROSS THE REGION W/POSSIBLE TSTMS AND WIND AND MVFR/IFR CONDITIONS. && .MARINE... NEAR TERM: NO HEADLINES. MAIN CHALLEGE WILL THE CONTINUING 4-5 FOOT SWELL WHICH IS OUT THERE ATTM. WINDS WILL INCREASE SOME OVERNIGHT W/THE COLD FROPA, BUT WINDS WILL RELAX ON SATURDAY AS HIGH PRES MOVES IN FROM CANADA. AREAS OF FOG WILL BE NUISANCE OVERNIGHT BUT VSBYS SHOULD IMPROVE LATER SATURDAY MORNING. USED THE NAM12 AND GFS FOR THE WINDS WHICH SUPPORT 10-15 KTS TONIGHT AND THEN SPEEDS FROP OFF FOR SATURDAY. BROUGHT THE SWELL DOWN TO 3 FT BY MIDDAY SATURDAY W/AN OFFSHORE FLOW. SHORT TERM: POSSIBLE SCA FOR SUNDAY NIGHT INTO MONDAY AS PRES GRADIENT TIGHTEN AHEAD AND W/THE FRONTAL PASSAGE. WINDS START COMING DOWN LATER MONDAY INTO TUESDAY. BACKED OFF A BIT ON THE WNAWAVE BY DROPPING THEM BACK 1-2 FEET. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT SHORT TERM...FITZSIMMONS LONG TERM...OKULSKI AVIATION...HEWITT MARINE...HEWITT/FITZSIMMONS
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
854 PM EDT SAT AUG 4 2012 .SYNOPSIS... A COLD FRONT WILL PUSH EAST FROM THE GREAT LAKES SUNDAY...BEFORE MOVING THROUGH THE MID-ATLANTIC SUNDAY NIGHT...BRINGING SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF IT. WEAK HIGH PRESSURE WILL MOVE OVER THE REGION FOR THE FIRST PART OF NEXT WEEK. && .NEAR TERM /THROUGH SUNDAY/... 00Z KIAD RAOB SHOWS THE POOR LAPSE RATES FROM 500 TO 800MB AND DRY LOW LEVELS. POPS WERE PULLED BACK FOR THE 730 UPDATE AND IT SEEMS THE SCATTERED SHOWERS IN THE SHENANDOAH VALLEY ARE ALL THERE WILL BE. FARTHER UPSTREAM IT IS A TALE OF TWO MCS/S OUT IN THE MIDWEST. THE 21Z HRRR HAS A DECENT DEPICTION OF THE ACTIVITY AND CONTAINS IT TO OHIO THROUGH THE REST OF THE NIGHT WITH SEEMS TO BE VERY REASONABLE SOLUTION WITH THE LEADING LINE REDUCING THE AVAILABLE ENERGY FOR THE STRONGER TRAILING LINE. PREVIOUS DISCUSSION... THE NIGHT WILL END UP FAIRLY QUIET WITH PATCHY FOG POSSIBLE AGAIN. DEFERRED FROM PUTTING IT IN THE GRIDS THOUGH SINCE DECOUPLING DOES NOT APPEAR TO BE WIDESPREAD TONIGHT...AND WOULD LIKE TO SEE WHERE IT RAINS BEFORE COMMITTING TO AN AREA. AN EXTREMELY HUMID NIGHT IS EXPECTED THOUGH...AND I LEANED CLOSER TO WARMER NAM LOWS...WHICH MAY BE IN THE UPPER 70S IN THE CITIES AND ALONG THE BAY. SUNDAY MORNING MAY ACTUALLY BE QUIET WEATHERWISE...THOUGH CONVECTION IS LIKELY TO DEVELOP SOONER THAN TODAY OUT WEST. RAISED AFTERNOON POPS TO LIKELY ALONG/WEST OF US 29 AS UPPER SUPPORT MOVES IN AHEAD OF AN ADVANCING COLD FRONT. STRONG TO SEVERE STORMS WILL BE POSSIBLE AGAIN...BUT LOOKING AT MODEL OUTPUT...I AM NOT YET SOLD ON HOW WIDESPREAD THE THREAT MAY BE. WHAT I AM SOLD ON IS LOCALLY HEAVY RAINFALL. PWATS JUMP OVER 2 INCHES /GFS HAS 2.35 INCHES AT 00Z MON/. BUT...THE STORMS ARE MOVING AT A GOOD CLIP BY THAT TIME. DID NOT ISSUE A FLASH FLOOD WATCH YET...BUT ONE MAY NEED TO BE CONSIDERED BY FUTURE SHIFTS FOR AREAS WEST OF A LINE FROM CUMBERLAND TO LURAY TO WAYNESBORO...WHERE ANTECEDENT CONDITIONS ARE MORE FAVORABLE. TOOK A MODEL BLEND FOR POPS AND HIGHS ON SUNDAY. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... SHORTWAVE TROUGH WILL LIFT NEWD ACROSS SRN QUEBEC WHILE SFC COLD FRONT WILL ENTER THE REGION SUN NGT. INTERACTION BETWEEN THE UPSTREAM TROUGH AND WRN ATLANTIC RIDGE WILL SLOW DOWN FORWARD PROGRESSION OF FRONT OVNGT AS IT APPROACHES I-95 AND SWLY FLOW ALOFT PARALLELS THE BOUNDARY. BEST CHANCE FOR SHOWERS AND STORMS WILL BE IN THE EVE AS ONGOING CONVECTION ALONG THE FRONT WILL MOVE INTO THE AREA. HEIGHT FALLS ASSOCIATED WITH THE APPROACH OF THE UPPER TROUGH AND DEVELOPMENT OF A 35-KT LLVL JET WILL SUPPORT A CONTINUATION OF CONVECTION WELL AFTER DARK. MAIN QUESTION WILL BE HOW LONG INTO THE EVE DOES THE SEVERE THREAT LAST. GIVEN THE MAGNITUDE OF LLVL WIND FIELD...WILL NEED TO MONITOR THE POTENTIAL FOR A QLCS TO MOVE THRU MON EVE. HOWEVER...THERE ARE FACTORS THAT WILL LIMIT THE THREAT OF ORGANIZED SEVERE WEATHER. THE BEST DYNAMICS REMAIN WELL NORTH AND WEST OF THE CWA WHILE STORMS MOVE INTO A STABILIZING ATMOSPHERE WITH THE LOSS OF DAYTIME HEATING. WITH THE FRONT SLOWING DOWN AND PWATS APPROACHING 2.25 INCHES...THERE IS A POTENTIAL FOR LOCALLY HVY RAINFALL AND FLASH FLOODING. THE FRONT WILL HAVE A DIFFICULT TIME CLEARING THE REGION MON. HARD TO JUSTIFY REMOVAL OF CHANCE POPS MON MRNG WITH THE FRONT IN THE AREA. CONVECTION WILL LIKELY REDEVELOP ALONG THE FRONT DURING THE AFTN IN RESPONSE TO DAYTIME HEATING. HIGHEST POPS WILL RESIDE SOUTH AND EAST OF DC...CLOSE TO WHERE THE FRONT MAY STALL. MRNG CLOUD COVER MAY LIMIT AMT OF DESTABILIZATION...BUT A STORM OR TWO NEAR THE FRONT MAY BE STRONG. DRIER AIR BEHIND THE FRONT SHOULD KEEP AREAS NORTH AND WEST OF DC DRY MON. MAX TEMPS 85-90F MON WILL BE CLOSE TO CLIMO. DRY CONDITIONS EXPECTED MON NGT AS WEAK HIPRES BUILDS IN FROM THE OH VLY. MIN TEMPS RANGE FROM THE UPPER 50S IN THE HIGHLANDS TO NEAR 70 IN THE URBAN AND COASTAL LOCALES. && .LONG TERM /TUESDAY THROUGH SATURDAY/... LARGE-SCALE PATTERN WILL FEATURE UPPER RIDGE BUILDING OVER THE GREAT BASIN REGION AND THE WRN AND CENTRAL ATLANTIC...WHILE TROUGHING DEVELOPS OVER THE ERN HALF OF THE CONUS. ACCORDINGLY...THE MID-ATLANTIC REGION WILL BE DISPLACED FROM THE INTENSE HEAT BUT TOO FAR SOUTH OF THE JET STREAM TO SEE A RELIEF FROM THE TYPICAL SUMMER HEAT AND HUMIDITY THRU THE END OF THE WEEK. DIFFUSE FRONTAL BOUNDARY NEAR THE NC/VA BORDER TUE MRNG WILL GRADUALLY LIFT NWD THRU THE AREA WED AND THU IN RESPONSE TO DEVELOPING SLY FLOW BETWEEN THE GREAT LAKES TROUGH AND BERMUDA HIGH. FROPA WILL BE MARKED BY A RETURN OF THE HUMIDITY AND SEASONABLY WARM HIGHS IN THE LOW TO MID 90S. BEST CHANCE TO SEE A DRY DAY CWA-WIDE WILL BE TUE...ALTHOUGH CANNOT RULE OUT AN ISO SHOWER OR STORM IN CENTRAL VA AND SRN MD. LONGWAVE TROUGH IS FCST TO SHARPEN LATE IN WEEK AS AN UPPER LOW DIGS SEWD OVER THE GREAT LAKES. BETTER CHANCES FOR SHOWERS AND STORMS FRI AND SAT AS THE LOW AND ASSOCIATED COLD FRONT APPROACH FROM THE WEST. THERE ARE CONSIDERABLE DIFFERENCES REGARDING TIMING OF FROPA. PREFER A SLOWER SOLUTION GIVEN AMPLIFYING PATTERN THIS TIME OF YEAR. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... SHOWERS POSSIBLE AT KMRB REST OF THE EVENING...QUIET OVERNIGHT WITH LITTLE INSTABILITY. PATCHY FOG POSSIBLE OVERNIGHT...MAINLY AT CHO AND MRB. NUMEROUS SHRA/TSRA SUNDAY AFTERNOON WITH GUSTY WINDS AND HEAVY RAIN. COLD FRONT WILL GRADUALLY MOVE THRU SUN NGT AND MON MRNG. SHRA/TSRA EXPECTED WITH FROPA. TEMPORARY VSBY RESTRICTIONS POSSIBLE IN STORMS. CLOUD COVER WILL MITIGATE IMPACT OF FOG ERY MON MRNG. CONVECTION MAY REDEVELOP NEAR OR JUST SE OF CHO/DCA ERY MON AFTN...DEPENDING ON TIMING OF FROPA. GENERALLY VFR CONDITIONS EXPECTED MIDWEEK...ALTHOUGH A FEW STORMS /MAINLY NEAR SRN AND ERN TERMINALS/ MAY DEVELOP DURING THE AFTN HRS EACH DAY WED AND THU. && .MARINE... SLY CHANNELING OVER MAIN SECTIONS OF THE BAY CONTINUES THROUGH THE EVENING WITH THE SCA THROUGH TONIGHT FOR ALL WATERS EXCEPT UPR TIDAL POTOMAC AND TIDAL PATAPSCO. MAY BE ABLE TO PULL BACK FARTHER BUT SLY FLOW AHEAD OF A SHORTWAVE WILL ENABLE GUSTS AROUND 20 KT ACROSS THE WATERS ON SUNDAY WHERE AN SCA IS UP FOR ALL ZONES. SCA EXTENDED INTO SUN NGT FOR THE SRN AND MID PORTION OF THE MD CHSPK BAY AND LOWER TIDAL POTOMAC. COLD FRONT PASSES THRU THE WATERS MON. A FEW STORMS MAY IMPACT THE WATERS MON AFTN...ESPECIALLY OVER THE SRN MARINE ZONES. STORMS COULD WARRANT SMW/S. A WEAKENING PRESSURE GRADIENT NEAR AND BEHIND THE FRONT WILL YIELD LIGHTER WINDS MON THRU MIDWEEK. SCA NOT EXPECTED DURING THIS TIME. && .TIDES/COASTAL FLOODING... DEPARTURES REMAIN 0.5 TO 0.7 FT ABOVE PREDICTED...BUT DESPITE THE FULL MOON NO FLOOD THRESHOLDS ARE EXPECTED TO BE TOPPED. WATER LEVELS SHOULD REMAIN BELOW MINOR FLOOD THRESHOLDS DURING THE NEXT COUPLE CYCLES. THE N/W WINDS BEHIND THE FRONT SHOULD PUSH THE ANOMALIES DOWN AT LEAST A LITTLE MORE BY MONDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR ANZ530-531-536- 539. SMALL CRAFT ADVISORY FROM 8 AM TO 8 PM EDT SUNDAY FOR ANZ535- 538. SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ532>534-537- 540>543. && $$ SYNOPSIS...JCE/BAJ NEAR TERM...JCE/BAJ SHORT TERM...JRK LONG TERM...JRK AVIATION...JCE/BAJ/JRK MARINE...JCE/BAJ/JRK TIDES/COASTAL FLOODING...JCE/BAJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
827 PM EDT SAT AUG 4 2012 .SHORT TERM...(TONIGHT) ISSUED AT 432 PM EDT SAT AUG 4 2012 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS LOOKING SHORTWAVE TROF ACROSS THE ERN DAKOTAS/MN. AT THE SFC...ASSOCIATED COLD FRONT IS SLICING THRU WRN LAKE SUPERIOR/WRN UPPER MI AND NW WI. DESPITE VIGOROUS LOOK OF SHORTWAVE...CONVECTION HAS BEEN KEPT IN CHECK BY ABUNDANT CLOUD COVER THAT HAS PERSISTED THRU THE DAY ACROSS GOOD PORTIONS OF UPPER MI AND NRN WI. LATEST SPC MESOANALYSIS SHOWS MLCAPE OF MOSTLY UNDER 500J/KG ACROSS THE FCST AREA. HIGHEST VALUES...A LITTLE OVER 500J/KG...ARE OVER THE E WHERE THERE HAS BEEN MORE SUNSHINE WITH SFC DWPTS AROUND 70F. IF MORE INSTABILITY HAD DEVELOPED...A FAIRLY SIGNIFICANT SVR WEATHER OUTBREAK WOULD PROBABLY BE GETTING UNDERWAY ACROSS THE FCST AREA AS DEEP LAYER SHEAR IS STEADILY INCREASING TOWARD THE 40-50KT RANGE DUE TO MIDLEVEL SPEED MAX APPROACHING THE AREA. MAIN SHOW TONIGHT WILL BE S OF THE AREA WITH CONVECTIVELY ENHANCED SHORTWAVE TRACKING TOWARD SRN WI/NRN IL/LWR MI. THE ONGOING ASSOCIATED CLUSTER OF STRONG/SVR STORMS WILL PASS S OF THE AREA. THAT SAID...OVER THE NEXT FEW HRS...SHRA/TSRA SHOULD TEND TO EXPAND NE ACROSS ROUGHLY THE E HALF OF THE FCST AREA AS HEIGHT FALLS AND RIGHT ENTRANCE OF UPPER JET STREAK WORK TO INCREASE UPWARD MOTION. THERE IS STILL THE POTENTIAL OF ISOLD SVR STORMS...BUT WITH CLOUD COVER NOW INCREASING EVEN OVER THE ERN FCST AREA TO PREVENT INSTABILITY FROM BUILDING HIGHER...IT APPEARS RISK OF SVR STORMS IS DIMINISHING. WILL KEEP SLIGHT RISK OF SVR WORDING IN HAZARDOUS WX OUTLOOK FOR THE NEXT FEW HRS OR SO. AFTER ANY SHRA/TSRA WITH COLD FRONT DEPART...ATTENTION TURNS TO VORT MAX AND SECONDARY COLD FRONT THAT WILL SWING INTO THE AREA LATE TONIGHT. THERE HAS BEEN FAIRLY SOLID COVERAGE OF SHRA AND EVEN SCT TSRA ACROSS SE MANITOBA INTO ADJACENT NRN ONTARIO WITH TROF AXIS THOUGH PCPN HAS TAKEN ON MORE OF A DIURNAL SCT COVERAGE THIS AFTN. AS TROF AXIS/VORT MAX DROP INTO THE AREA...THERE SHOULD BE DECENT SHRA COVERAGE LATE TONIGHT INTO SUN MORNING...ESPECIALLY SINCE CAA DROPS 850MB TEMPS TO AROUND 6C BY 12Z SUN. WITH WATER TEMPS AROUND 20C ON LAKE SUPERIOR...THE OVERWATER INSTABILITY WILL BE MORE THAN SUFFICIENT FOR LAKE ENHANCEMENT UNDER CYCLONIC FLOW WITH ARRIVAL OF VORT MAX. THUS...EXPECT SCT/NMRS SHRA TO DEVELOP LATE TONIGHT OVER THE NW HALF OF UPPER MI. AS ALWAYS...UPSLOPE NW WINDS WILL LEAD TO MOST NMRS COVERAGE OVER THE HIGHER TERRAIN DOWNWIND OF THE LAKE. .LONG TERM...(SUNDAY THROUGH SATURDAY) ISSUED AT 432 PM EDT SAT AUG 4 2012 GOOD AGREEMENT FM THE GFS/ECMWF/GEM-NHEM WITH OVERALL UPPER AIR PATTERN THROUGH THIS WEEK. PATTERN STARTS OFF WITH DEEP TROUGH OVER THE UPPER GREAT LAKES AND BROAD WEST-TO-EAST RIDGE ACROSS THE SOUTHERN TIER OF THE CONUS. BY MIDWEEK...RIDGE BECOMES MORE AMPLIFIED OVER INTERMOUNTAIN WEST INTO WESTERN CANADA WHILE TROUGHING REMAINS IN PLACE OVER EASTERN CANADA AND THE GREAT LAKES AND NORTHEAST CONUS. WEATHER WILL STAY ON THE ACTIVE SIDE AS MULTIPLE SYSTEMS IMPACT THE UPPER GREAT LAKES. FIRST WILL BE RIGHT AT BEGINNING OF LONG TERM ON SUNDAY. ANOTHER WEAKER COLD FRONT COMES THROUGH AREA ON TUESDAY. MUCH STRONGER LOW PRESSURE SYSTEM FCST TO PUSH ACROSS GREAT LAKES LATER THURSDAY INTO FRIDAY. IT IS THIS SYSTEM THAT SHOWS THE MOST POTENTIAL TO PRODUCE NOTEABLE PRECIPITATION AMOUNTS IN THE LONG TERM. SINCE THE LARGE TROUGH IS CLOSE BY AND RIDING REMAINS WELL TO THE WEST...EXPECT TEMPERATURES TO GENERALLY BE WITHIN A FEW DEGREES OF NORMAL. ONLY WARM EXCEPTION WILL BE ON MONDAY AHEAD OF ANOTHER COLD FRONT. SOME COOL PERIODS ARE EXPECTED AS WELL. COOLEST OF THE BUNCH LIKELY WILL BE ON SUNDAY...BUT SIMILAR COOLER TEMPERATURES MAY OCCUR AGAIN ON FRIDAY ON IN WAKE OF LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES. A VERY CHAGEABLE WEATHER DAY IS IN STORE FOR SUNDAY. COLD FRONT THROUGH UPR MICHIGAN BY DAYBREAK WHILE SFC LOW PUSHES ACROSS JAMES BAY. COOL AND MOIST CYCLONIC FLOW SFC THROUGH H7 AFFECTS MOST CWA THROUGH LATE MORNING THEN HEIGHTS RISE QUICKLY WHILE EDGE OF SFC HIGH BUILDS IN MID-LATE AFTN. MOIST CYCLONIC FLOW AND THERMAL TROUGH WITH H85 TEMPS AS LOW AS +5C IN ADDITION TO A SHARP SECONDARY WAVE DROPPING THROUGH MEAN TROUGH SHOULD COMBINE TO BRING A PERIOD OF SHOWERS TO PORTIONS OF CWA THROUGH THE MORNING. WARM LK SUPERIOR TEMPS NEAR +20C ALSO ALLOW LAKE EFFECT PROCESSES TO ENHANCE PCPN AS DELTA T/S ARE AROUND 14-15C/LAKE INDUCED CAPES UP TO 250 J/KG. INCREASED POPS OVER UPSLOPE AREAS FAVORED BY NW BLYR WINDS. HIGHEST POPS IN THE MORNING...THEN RAPIDLY DROPPING OFF IN THE AFTN AS AREA QUICKLY RESIDES IN SUBSIDENCE REGION OF THE STRONG SHORTWAVE. SKIES PROBABLY CLEAR QUICKLY IN THE AFTN DUE TO SUBSIDENCE AND DRY AIR. TEMPS KIND OF TRICKY...BUT FOLLOWED TREND CLOSER TO GEM-REGIONAL SHOWING TEMPS STUCK IN THE MID 50S-LOW 60S INTO EARLY AFTN...THEN RISING TOWARD 70 DEGREES LATER IN THE DAY WITH INCREASING SUNSHINE. GUSTY WINDS OTHER FACTOR ON SUNDAY AS DEEP MIXING EXPECTED THROUGH EARLY AFTN BEFORE H85 WARM ADVECTION INCREASES STABILITY. MIXED LAYER WINDS THROUGH 16Z 35-40KT AND EXPECT GOOD PORTION OF THESE TO MIX TO SFC. STRONGEST WINDS NEAR EXPOSED LK SUPERIOR SHORE OF CNTRL AND EAST. EXPECT WINDS TO DIMINISH BY LATE DAY. HIGH PRESSURE AXIS REMAINS JUST SOUTH OF AREA SUNDAY NIGHT BUT WINDS BECOME LIGHT ENOUGH/PWAT LOW ENOUGH TO SEE SOME RADIATIONAL COOLING TAKE PLACE. LOWEST MINS SEEM LIKELY IN THE INTERIOR CNTRL AND EAST WHERE COLD SPOTS MAY DROP INTO LOWER 40S. MUCH DIFFERENT DAY ON MONDAY COMPARED TO COOLER/WINDY DAY ON SUNDAY. HIGH PRESSURE SLIDES EAST AND A WEAK COLD FRONT IS FCST TO DROP INTO UPR LAKES MONDAY NIGHT. NOT A LOT OF CLOUD COVER AHEAD OF FRONT THOUGH OTHER THAN ON THE KEWEENAW IN THE LATER AFTN. WITH H85 TEMPS 15C-16C EXPECT HIGHS TO REACH WELL INTO THE 80S AWAY FM LK MICHIGAN SHORE. AS UPR JET SLIDES ACROSS ONTARIO MONDAY NIGHT AND MID-LEVEL FGEN INCREASES OVR LK SUPERIOR...EXPECT BAND OF SHRA/TSRA TO DEVELOP ALONG SFC FRONT. FRONT SLIDES THROUGH CWA ON MONDAY NIGHT...WITH BETTER CHANCES OF SHRA/TSRA TIED INTO THE MID-LEVEL FORCING. SOUNDINGS SHOW DRY AIR LINGERING BLO H85-H7 DUE TO LIMITED MOISTURE ADVECTION FM THE GULF INTO THIS SYSTEM. SO...COVERAGE OF PRECIP WILL BE SPOTTY WITH THE FRONT. HIGH PRESSURE BUILDS BACK IN FOR TUESDAY WITH TEMPS IN THE 70S NORTH AND NEARING 80 DEGREES OVR THE SOUTH AND NEAR LK MICHIGAN. EXTENDED...MAIN CHANCES FOR SHRA/TSRA COME IN LATER WEDNESDAY NIGHT INTO THURSDAY AS ANOTHER UPPER LOW AND SFC LOW MOVE ACROSS THE UPR LAKES. CYCLONIC FLOW LINGERING IN THE WAKE OF THE SFC LOW COULD KEEP SOME SHRA GOING OVR THE AREA INTO FRIDAY...KIND OF SIMILAR TO WHAT IS EXPECTED ON SUNDAY. WITH EXPECTED CLOUDS/PCPN...TRIMMED TEMPS THURSDAY AND FRIDAY CLOSER TO LK SUPERIOR WHERE ONSHORE NORTHEAST FLOW SHOULD RESULT IN COOLER CONDITIONS. INCREASED WINDS OVR LK SUPERIOR SOME COMPARED TO GUIDANCE CONSENSUS BUT MAY NEED TO INCREASE FURTHER WITH LATER FCSTS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 823 PM EDT SAT AUG 4 2012 COLD FRONT MOVING ACROSS THE AREA THIS EVENING FOLLOWED BY ANOTHER COLD FRONT LATE TONIGHT THROUGH SUNDAY MORNING WILL BE THE GREATEST CONCERN DURING THIS TAF PERIOD. SATELLITE IMAGERY SHOWS CMX AND SAW UNDER BKN TO OVC SKIES AS OF 19Z...WITH CLEARING TO THE WEST OVER MUCH OF NORTHERN WI AND WESTERN UPPER MI INCLUDING THE IWD TAF SITE. DID NOT DEVIATE MUCH FROM PREVIOUS FORECAST WITH STRONG WINDS ASSOCIATED WITH SECONDARY COLD FRONT LATE TONIGHT INTO SUNDAY MORNING BRINGING GUSTY NW WINDS TO ROUGHLY 25-30KT AS PRESSURE GRADIENT TIGHTENS BETWEEN HIGH PRESSURE TO THE SOUTHWEST AND A LOW PRESSURE CENTERED OVER NORTHEASTERN ONTARIO. AS THE PRESSURE GRADIENT RELAXES OVER THE REGION TOWARD THE END OF THE TAF PERIOD EXPECT WINDS TO BEGIN TO DIMINISH. EXPECT IFR CEILING CONDITIONS TO BE POSSIBLE LATER TONIGHT THROUGH EARLY SUNDAY MORNING ALONG WITH REDUCED VISIBILITIES AT EACH OF THE TAF SITES AS NEXT ROUND OF SHOWERS MOVES INTO THE AREA. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 432 PM EDT SAT AUG 4 2012 COLD FRONT PASSES ACROSS LK SUPERIOR THIS EVENING. PERIOD OF STRONG WINDS AND HIGH WAVES /LIKELY OVR 10 FEET/ EXPECTED LATE TONIGHT THROUGH MUCH OF SUNDAY AFTERNOON. EXPECT 25-30 KT WINDS FM THE NORTHWEST DURING ON SUNDAY WITH FREQUENT GALE GUSTS 35-40 KTS. A GALE WATCH HAS BEEN POSTED FOR THE EAST HALF OF LK SUPERIOR MOST OF SUNDAY. WINDS DIMINISH SUNDAY NIGHT...BUT THEN INCREASE FM THE SOUTHWEST ON MONDAY AHEAD OF A COLD FRONT THAT SLIDES THROUGH ON MONDAY NIGHT. IN WAKE OF THE FRONT...EXPECT WINDS 20 KTS OR LESS TUESDAY INTO WEDNESDAY AS HIGH PRESSURE MOVES ACROSS THE REGION. WINDS MAY END UP STRONGER THAN FCST FOR LATE THIS WEEK AS DETAILS ARE SORTED OUT REGARDING ANOTHER LOW PRESSURE SYSTEM MOVING THROUGH THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY EVENING FOR LSZ251- 267. GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR LSZ249-250-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...KEC MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1030 PM CDT SAT AUG 4 2012 .DISCUSSION...ISSUED 216 PM CDT MAIN FORECAST CHALLENGE TODAY IS REMEMBERING HOW TO FORECAST BELOW NORMAL TEMPERATURES... SINCE WE/LL DEFINITELY HAVE THEM THROUGH TOMORROW... AND DON/T APPEAR TO HAVE ANY OF THE RECENT WELL ABOVE NORMAL READINGS RETURNING ANYTIME SOON. IN THE BIG PICTURE... THE PROMINENT UPPER RIDGE THAT HAS BEEN ANCHORED OVER THE CENTRAL OF THE COUNTRY FOR QUITE SOME TIME WILL RETROGRADE WEST THROUGH THE WEEK... WITH NORTHWEST UPPER FLOW PREVAILING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THE DEEP TROUGH CURRENTLY WORKING INTO MINNESOTA WILL MOVE OUT FAIRLY QUICKLY... SO WE WON/T BE IN THE /ICEBOX/ FOR TOO LONG... BUT AS THE WEEK UNFOLDS WE WILL PROGRESSIVELY SEE LOWER HEIGHTS WORK OVER THE REGION AS THE UPPER RIDGE MIGRATES WEST. MONDAY ACTUALLY LOOKS LIKE IT MAY TURN OUT TO BE THE WARMEST DAY AS WE BRIEFLY GET INTO SOME DECENT RETURN FLOW AND HIGHER HEIGHTS ON THE BACKSIDE OF THE AMPLIFIED UPPER TROUGH CURRENTLY IN THE AREA. AFTER THAT WE WILL SEE A SERIES OF GENERALLY WEAK SHORTWAVES DROP THROUGH THE AREA OVER THE BALANCE OF THE WEEK... BRINGING A FEW CHANCES FOR PCPN BUT NOTHING THAT APPEARS OVERLY SIGNIFICANT AT THIS POINT IN TIME. IN THE SHORT TERM... WE WILL HAVE A CHANCE FOR SOME SHRA AND PERHAPS A LITTLE THUNDER OVER THE NORTHERN HALF OF THE CWFA THROUGH EARLY EVENING AS THE UPPER THROUGH AND SECONDARY COLD FRONT PUSH ACROSS THE AREA. THE HRRR TAKES SOME OF THE ACTIVITY FARTHER SOUTH THAN CURRENTLY FORECAST... BUT IT IS SOMETHING WE/LL NEED TO MONITOR AND POTENTIALLY EXTEND FARTHER SOUTH IF NEEDED. THINGS SHOULD BE SCATTERED IN NATURE... AS CURRENTLY SEEN OVER EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA... BUT WILL MLCAPE OF 250-750 J/KG CAN/T RULE OUT A FEW THUNDERSTORMS AND BURSTS OF HEAVIER RAIN... MAINLY OVER THE FAR NORTHERN CWFA WHERE THE BEST COMBINATION OF INSTABILITY AND FORCING ARE EXPECTED. HIGH PRESSURE BUILDS IN OVERNIGHT AND REMAINS FIRMLY IN CONTROL THROUGH SUNDAY NIGHT. WE THEN FIND OURSELVES ON THE BACKSIDE OF THE HIGH ON MONDAY... AND LOOK TO GET SOME DECENT WARM ADVECTION AND MIXING... WITH HIGHS GETTING BACK INTO THE MIDDLE TO UPPER 80S OVER MUCH OF THE AREA AFTER A VERY COOL SUNDAY WITH TEMPERATURES IN THE 70S. CONTINUED TO MENTION SOME LOW POPS MONDAY EVENING OVER THE SOUTHERN PART OF THE AREA AS A WEAK SHORTWAVE AND COLD FRONT DROP ACROSS THE AREA. NOT TOO CONFIDENT THIS FEATURE WILL PRODUCE ANYTHING GIVEN THE MEAGER MOISTURE RETURN AHEAD OF IT... BUT IF IT DOES MANAGE TO SQUEEZE ANYTHING OUT IT LOOKS LIKE THE BEST CHANCE WOULD BE OVER THE SOUTH. ANOTHER CHANCE FOR SHRA/TSRA IS INCLUDED FOR TUESDAY NIGHT INTO THURSDAY... AS A COUPLE OF ADDITIONAL SHORTWAVES QUICKLY DIVE SOUTHEAST THROUGH THE AREA IN THE PREVAILING NORTHWEST FLOW. ULTIMATELY THE BEST CHANCE FOR PCPN WILL BE NEAR WHERE THE BAROCLINIC ZONE HANGS UP... AND AT THIS POINT IT IS STILL A BIT TOO EARLY TO PIN THAT DOWN... SO UNFORTUNATELY BLANKETED MUCH OF THE AREA IN POPS FOR A 36-48 HOUR PERIOD. DID REMOVE MUCH OF THE POPS FOR THE END OF THE WEEK... SINCE AT THAT POINT THE GFS AND ECMWF ARE IN SUFFICIENT AGREEMENT IN DISPLACING THE BAROCLINIC ZONE WEST OF OUR AREA AND ESSENTIALLY KEEPING US A FAIRLY DRY AND COOL NORTHWEST UPPER FLOW. DEPENDING UPON THE EVENTUAL DEGREE OF COOLNESS WITH THE MID-LEVEL COLD POOL WE COULD NEED SOME POPS FOR DIURNAL SHRA FRIDAY AND SATURDAY... BUT CHOSE TO LEAVE THAT OUT FOR NOW RATHER THAN CARPET BOMBING ANOTHER 48 HOURS WITH LOW POPS. && .AVIATION.../06Z TAF ISSUANCE/ SECONDARY CDFNT JUST W OF MSP NOW WITH 3 MB SFC PRESSURE RISES BEHIND FNT. FAIRLY TIGHT PRESSURE GRADIENT BEHIND FNT WILL MAINTAIN WINDS AROUND 10 KTS OVERNIGHT AT TAF SITES. POSTFRONTAL CLDS HAVE BEEN THINNING THIS EVENING...MAY BE A PRD OF A COUPLE HOURS BEHIND FRONT FOR BKN CIGS ARND 040. GRADIENT RELAXES SUNDAY MORNING AS HIGH PRESSURE BUILDS IN. STILL ENUF NW WINDS ALOFT FOR SOME GUSTS ARND 20 KTS AT EAU. KMSP...SECONDARY CDFNT WILL BE EAST OF MSP BY TAF ISSUE TIME AND MAY HAVE A PRD OF SCT-BKN040 UNTIL AROUND 08Z. FAIRLY TIGHT PRESSURE GRADIENT WILL MAINTAIN NW WINDS AROUND 10 KTS OVERNIGHT. GRADIENT RELAXES DURING THE DAY SUNDAY AS HIGH PRESSURE BUILDS IN. /OUTLOOK/ .MONDAY...VFR. WINDS SW AT 10KT. .TUESDAY...VFR. WINDS NW AT 5KT. .WEDNESDAY...VFR. WINDS SOUTH 5 KNOTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
630 PM CDT SAT AUG 4 2012 .UPDATED FOR 00Z AVIATION DISCUSSION BELOW... .DISCUSSION... MAIN FORECAST CHALLENGE TODAY IS REMEMBERING HOW TO FORECAST BELOW NORMAL TEMPERATURES... SINCE WE/LL DEFINITELY HAVE THEM THROUGH TOMORROW... AND DON/T APPEAR TO HAVE ANY OF THE RECENT WELL ABOVE NORMAL READINGS RETURNING ANYTIME SOON. IN THE BIG PICTURE... THE PROMINENT UPPER RIDGE THAT HAS BEEN ANCHORED OVER THE CENTRAL OF THE COUNTRY FOR QUITE SOME TIME WILL RETROGRADE WEST THROUGH THE WEEK... WITH NORTHWEST UPPER FLOW PREVAILING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THE DEEP TROUGH CURRENTLY WORKING INTO MINNESOTA WILL MOVE OUT FAIRLY QUICKLY... SO WE WON/T BE IN THE /ICEBOX/ FOR TOO LONG... BUT AS THE WEEK UNFOLDS WE WILL PROGRESSIVELY SEE LOWER HEIGHTS WORK OVER THE REGION AS THE UPPER RIDGE MIGRATES WEST. MONDAY ACTUALLY LOOKS LIKE IT MAY TURN OUT TO BE THE WARMEST DAY AS WE BRIEFLY GET INTO SOME DECENT RETURN FLOW AND HIGHER HEIGHTS ON THE BACKSIDE OF THE AMPLIFIED UPPER TROUGH CURRENTLY IN THE AREA. AFTER THAT WE WILL SEE A SERIES OF GENERALLY WEAK SHORTWAVES DROP THROUGH THE AREA OVER THE BALANCE OF THE WEEK... BRINGING A FEW CHANCES FOR PCPN BUT NOTHING THAT APPEARS OVERLY SIGNIFICANT AT THIS POINT IN TIME. IN THE SHORT TERM... WE WILL HAVE A CHANCE FOR SOME SHRA AND PERHAPS A LITTLE THUNDER OVER THE NORTHERN HALF OF THE CWFA THROUGH EARLY EVENING AS THE UPPER THROUGH AND SECONDARY COLD FRONT PUSH ACROSS THE AREA. THE HRRR TAKES SOME OF THE ACTIVITY FARTHER SOUTH THAN CURRENTLY FORECAST... BUT IT IS SOMETHING WE/LL NEED TO MONITOR AND POTENTIALLY EXTEND FARTHER SOUTH IF NEEDED. THINGS SHOULD BE SCATTERED IN NATURE... AS CURRENTLY SEEN OVER EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA... BUT WILL MLCAPE OF 250-750 J/KG CAN/T RULE OUT A FEW THUNDERSTORMS AND BURSTS OF HEAVIER RAIN... MAINLY OVER THE FAR NORTHERN CWFA WHERE THE BEST COMBINATION OF INSTABILITY AND FORCING ARE EXPECTED. HIGH PRESSURE BUILDS IN OVERNIGHT AND REMAINS FIRMLY IN CONTROL THROUGH SUNDAY NIGHT. WE THEN FIND OURSELVES ON THE BACKSIDE OF THE HIGH ON MONDAY... AND LOOK TO GET SOME DECENT WARM ADVECTION AND MIXING... WITH HIGHS GETTING BACK INTO THE MIDDLE TO UPPER 80S OVER MUCH OF THE AREA AFTER A VERY COOL SUNDAY WITH TEMPERATURES IN THE 70S. CONTINUED TO MENTION SOME LOW POPS MONDAY EVENING OVER THE SOUTHERN PART OF THE AREA AS A WEAK SHORTWAVE AND COLD FRONT DROP ACROSS THE AREA. NOT TOO CONFIDENT THIS FEATURE WILL PRODUCE ANYTHING GIVEN THE MEAGER MOISTURE RETURN AHEAD OF IT... BUT IF IT DOES MANAGE TO SQUEEZE ANYTHING OUT IT LOOKS LIKE THE BEST CHANCE WOULD BE OVER THE SOUTH. ANOTHER CHANCE FOR SHRA/TSRA IS INCLUDED FOR TUESDAY NIGHT INTO THURSDAY... AS A COUPLE OF ADDITIONAL SHORTWAVES QUICKLY DIVE SOUTHEAST THROUGH THE AREA IN THE PREVAILING NORTHWEST FLOW. ULTIMATELY THE BEST CHANCE FOR PCPN WILL BE NEAR WHERE THE BAROCLINIC ZONE HANGS UP... AND AT THIS POINT IT IS STILL A BIT TOO EARLY TO PIN THAT DOWN... SO UNFORTUNATELY BLANKETED MUCH OF THE AREA IN POPS FOR A 36-48 HOUR PERIOD. DID REMOVE MUCH OF THE POPS FOR THE END OF THE WEEK... SINCE AT THAT POINT THE GFS AND ECMWF ARE IN SUFFICIENT AGREEMENT IN DISPLACING THE BAROCLINIC ZONE WEST OF OUR AREA AND ESSENTIALLY KEEPING US A FAIRLY DRY AND COOL NORTHWEST UPPER FLOW. DEPENDING UPON THE EVENTUAL DEGREE OF COOLNESS WITH THE MID-LEVEL COLD POOL WE COULD NEED SOME POPS FOR DIURNAL SHRA FRIDAY AND SATURDAY... BUT CHOSE TO LEAVE THAT OUT FOR NOW RATHER THAN CARPET BOMBING ANOTHER 48 HOURS WITH LOW POPS. && .AVIATION.../00Z TAF ISSUANCE/ SCT/BKN LAYERING STRATOCU OVER MUCH OF THE REGION THIS EVENING. STILL WILL MAINTAIN VFR. SECONDARY FRONT MOVING THROUGH KAXN NOW WITH WIDELY SCT -SHRA...AND WILL HOLD ONTO THE VCSH FOR A COUPLE HOURS. UPPER TROUGH WILL SWING EAST OVER WISCONSIN LATER TONIGHT...AND SHOULD SEE CLEARING FROM WEST TO EAST. FEW CUMULUS MAY OP OVER FAR EASTERN AREAS EARLY SUNDAY...BUT SHOULD DRY UP DURING THE AFTERNOON. WESTERLY WIND THIS EVENING...WILL BECOME MORE NORTHWEST WITH PASSAGE OF SECONDARY FRONT. COULD SEE AN HOUR OR TWO OF GUSTINESS WITH CAA PATTERN...BUT THAT SHOULD BE MAINLY OVER WESTERN AREAS THIS EVENING...THEN INTO WESTERN WISCONSIN DEVELOPING SUNDAY MORNING. HIGH PRESSURE WILL DOMINATE THE REGION WITH DRY/VFR CONDITIONS WELL INTO NEXT WEEK. KMSP...SCT/BKN LAYERED CU OVER AREA THIS EVENING. MAY SEE MORE BKN POTENTIAL WITH PASSAGE OF SECONDARY COLD FRONT BUT WILL STILL BE VFR. CLEARING LATER TONIGHT WITH MAINLY SKC INTO SUNDAY. WESTERLY SURFACE WINDS INTO THE EVENING BECOMING NORTHWEST THEE TURNING MORE SOUTHWEST TO SOUTH INTO SUNDAY EVENING. /OUTLOOK/ .MONDAY...VFR. WINDS SW AT 10KT. .TUESDAY...VFR. WINDS NW AT 5KT. .WEDNESDAY...VFR. WINDS SOUTH 5 KNOTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$
AREA FORECAST DISCUSSION
NWS GLASGOW MT
314 PM MDT FRI AUG 3 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY... A LARGE MIDLEVEL LOW IS CURRENTLY SPINNING OVER NORTHEAST MONTANA. THIS SYSTEM PULLED A COLD FRONT THROUGH YESTERDAY AND BROUGHT WIDESPREAD SHOWERS AND CLOUD COVER TO THE REGION. WITH CLOUD COVER AND RAIN ACTIVITY...HIGH TEMPERATURES HAVE NOT BEEN REACHING FORECAST VALUES...EXCEPT IN THOSE AREAS WHICH SAW BREAKS IN THE OVERCAST. SOME THUNDERSHOWER ACTIVITY HAS ALSO BEEN NOTED OVER PHILLIPS COUNTY WHICH SAW SOME BREAKS IN CLOUDS AND SURFACE WARMING. RADAR TRENDS AND RAP GUIDANCE CONTINUES SHOWER ACTIVITY WITH SOME ISOLATED THUNDER THROUGH MIDNIGHT WITH SHOWERS ENDING GRADUALLY FROM WEST TO EAST AS THE SYSTEM PROGRESSES EASTWARD. WINDS HAVE BEEN BARELY STRONG ENOUGH TO JUSTIFY CONTINUING THE LAKE WIND ADVISORY...HOWEVER...THEY HAVE BEEN CONSISTENTLY OVER 20MPH AT A NUMBER OF STATIONS AROUND THE LAKE. WINDS WILL DECLINE BY OR SHORTLY AFTER NIGHTFALL AS SURFACE MIXING DECLINES AND SURFACE PRESSURE RELAXES WITH THE PASSAGE OF THE WEATHER SYSTEM. IN THE WAKE OF THIS SYSTEM...THE NEXT RIDGE MOVES IN FAIRLY QUICKLY AND WILL BEGIN TO WARM THE REGION BY SUNDAY. MARTIN .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... A FEW CHANGES IN THE EXTENDED FORECAST DROPPED POPS ACROSS THE WESTERN ZONES TUESDAY NIGHT. DECIDED TO STAND PAT WITH THE POPS THAT WERE IN THE FORECAST FOR WEDNESDAY THROUGH FRIDAY EVEN THOUGH MODELS ARE HINTING AT A RATHER LARGE RIDGE ACROSS CENTRAL AND EASTERN MONTANA STARTING ON TUESDAY THROUGH THURSDAY WITH A SHORTWAVE MOVING ACROSS ALBERTA AND SOUTHERN SASKATCHEWAN THURSDAY NIGHT THROUGH FRIDAY. MODELS ALL SHOW THIS SHORTWAVE BUT DIFFER ON WHETHER IT WILL PRODUCE ANY RAINFALL. THE PRIMARY DIFFERENCE IS THAT THE MODELS ARE STRENGTHENING THE MID WEEK UPPER RIDGE SO THAT IS WHY I DECIDE TO LOWER POPS TUESDAY NIGHT THROUGH THURSDAY. THE 12Z MODEL RUNS ARE IN BETTER AGREEMENT WITH THIS FEATURE THEN THEY WERE WITH THE 00Z MODELS RUNS. RSMITH PREVIOUS DISCUSSION...THE EXTENDED FORECAST SHOWS LITTLE CHANGE AGAIN TONIGHT FROM THE LAST FEW MODEL RUNS. THE BEGINNING OF THE PERIOD SUNDAY NIGHT/MONDAY MORNING HAS RIDGING BUILDING INTO NORTHEAST MONTANA. THIS WILL HOLD OVER THE REGION THROUGH TUESDAY. THEN THE RIDGE MOVES A TOUCH SOUTH ALLOWING SOME RIPPLES IN THE UPPER FLOW TO COME INTO PLAY. STILL NO MAJOR EVENT TO POINT TOWARDS A BETTER CHANCE OF CONVECTION OVER ANOTHER SHORTWAVE. THEREFORE KEPT THE POPS LOW MID WEEK THROUGH THE END OF THE EXTENDED. TEMPERATURES WILL CONTINUE WITH AN ABOVE NORMAL TREND FOR THE REGION THROUGH THE ENTIRE PERIOD. PROTON && .AVIATION... PRIMARILY VFR CEILINGS BUT COULD HAVE TEMPORARY MVFR CEILING ACROSS THE TERMINALS DURING THIS AFTERNOON AND EVENING WITH CEILING DROPPING BELOW 2000 FT AGL. EXPECT SCATTERED RAIN SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS TO CONTINUE ACROSS THE TERMINALS THROUGH TONIGHT. NORTHWEST WINDS WILL DROP THIS EVENING FROM 15 TO 25 KNOTS THIS AFTERNOON TO BELOW 10 KNOTS THIS EVENING. RSMITH && .GLASGOW WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR FOR FORT PECK LAKEFORT PECK LAKE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
628 PM CDT SAT AUG 4 2012 .AVIATION...00Z KGRI TAF. VFR WEATHER...CLEAR SKIES AND NO VISIBILITY RESTRICTIONS...EXPECTED THE NEXT 24 HOURS DUE TO HIGH PRESSURE BUILDING OVER THE AREA. && .PREV DISCUSSION... /ISSUED 406 PM CDT SAT AUG 4 2012/ SHORT TERM...THROUGH SUNDAY AFTERNOON. PRIMARY ISSUES THROUGH THE NEXT 24 HOURS INCLUDE TIMING THE THE LAST FEW HOURS OF LINGERING ISOLATED/SCATTERED LIGHT PRECIP THROUGH LATE AFTERNOON...FOLLOWED BY JUST HOW COOL WILL IT GET TONIGHT. 19Z OBJECTIVE SURFACE ANALYSIS CENTERS A 1022MB HIGH OVER MT/WY...WITH THE RIDGE AXIS EXTENDING DOWN INTO WESTERN NEB. THE MUCH-AWAITED STRONGEST COLD FRONT WE HAVE SEEN AWHILE HAS PUSHED WELL OFF TO THE SOUTH AND EAST...NOW ALIGNED ALONG FROM EASTERN IA TO THE TX PANHANDLE. ALTHOUGH MID AFTERNOON WINDS CONTINUE TO GUST OVER 20 MPH IN MANY AREAS FROM THE NORTH/NORTHWEST...THEY ARE STARTING A GRADUAL DECLINE AS THE STRONGEST PRESSURE RISES SLIDE SOUTHEAST WITH THE FRONT. RADAR IMAGERY AND VISIBLE SATELLITE AROUND 1930Z GENERALLY CONFIRM THE EARLIER EXPECTATIONS OF ISOLATED/SCATTERED MAINLY LIGHT HIGH BASED RAIN SHOWERS STARTING TO INCREASE IN COVERAGE A BIT ACROSS THE SOUTHERN 1/2 OF THE CWA...ALTHOUGH NO LIGHTNING STRIKES HAVE YET BEEN DETECTED. WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA REVEAL A SEASONABLY STRONG MID LEVEL VORT MAX TRACKING EAST NEAR FAR NORTHERN MN...WITH THE 500MB SHORTWAVE AXIS TRAILING SOUTHWEST TO THE LOCAL AREA...WHILE RIDGING DOMINATES THE SOUTH CENTRAL AND WEST CENTRAL CONUS. TEMP WISE THIS AFTERNOON...STILL ANTICIPATING SOME LATE DAY SUNSHINE TO BOOST AT LEAST MUCH OF THE NORTHWEST 1/2 OF THE CWA INTO THE LOW 80S...BUT THE JURY IS STILL OUT ON WHETHER PARTS OF THE SOUTHEAST...MAYBE EVEN HASTINGS...WILL EVEN MAKE IT TO 80 GIVEN THE EXTENSIVE MID CLOUDS LINGERING LONGER. SEASONABLY DRY AIR IN THE FORM OF MID 40S-LOW 50S DEWPOINTS CONTINUE TO INVADE MUCH OF THE CWA FROM THE NORTHWEST...ALTHOUGH SOME UPPER 50S ARE STILL HANGING ON IN THE SOUTHEAST. STARTING OFF WITH THE NEXT FEW HOURS THROUGH 00Z...JUST MADE A LAST MINUTE DECISION TO PULL THUNDER MENTION ALTOGETHER...AS LATEST HOURLY MESOANALYSIS AND RAP INSTABILITY PROGS INDICATE BARELY EVEN 100 J/KG MUCAPE REMAINING IN THE FAR SOUTHEAST COUNTIES...AND ONGOING LIGHT SHOWERS HAVE NOT EXHIBITED DETECTABLE LIGHTNING AT ALL OVER THE PAST FEW HOURS. THESE LINGERING SHOWERS OVER THE NEXT FEW HOURS WILL MAINLY AFFECT LIMITED AREAS SOUTHEAST OF A LINE FROM HEBRON-STOCKTON...AND WILL CARRY ISOLATED/SCATTERED SHOWER WORDING FOR JUST A FEW MORE HOURS TO COVER THEM. THIS LINGERING PRECIP IS CLEARLY TIED TO A QUICKLY DEPARTING MID LEVEL CONVERGENCE/FRONTOGENETIC ZONE EVIDENT AT 700MB. GETTING TO THE OFFICIAL NIGHT PERIOD 00Z-12Z...BY THE START OF THE EVENING ANTICIPATE CONSIDERABLE CLEAR SKIES NEARLY CWA-WIDE...AS THE BACK EDGE OF THE PRIMARY MID DECK AND ASSOCIATED SHOWERS/POSSIBLE WEAK STORMS SHOULD BE JUST OFF TO THE SOUTH/EAST OF THE CWA BY THEN. AS A RESULT...HAVE ESSENTIALLY ZERO POPS THROUGH THE NIGHT AREA- WIDE...AS THE TRAILING SOUTHWEST PORTION OF THE POTENT MID LEVEL WAVE CONTINUES EXITING STAGE RIGHT...REACHING AN AXIS FROM NORTHERN WI TO IL BY 12Z. IN ITS WAKE...A PLEASANT AND EVEN SEASONABLY COOL NIGHT WILL SETTLE INTO THE CENTRAL PLAINS. AT THE SURFACE...NORTH BREEZES WILL REALLY LIGHTEN BY SUNSET...AND BECOME NEARLY CALM THROUGH THE NIGHT IN SOME AREAS AS A 1023MB HIGH PRESSURE AXIS CENTERS ITSELF DIRECTLY OVER THE AREA. THE COMBINATION OF THE INVADING DRY AIR...CLEARING SKIES AND LIGHT BREEZES SHOULD SET THE STAGE FOR A RATHER COOL NIGHT BY EARLY AUG STANDARDS. LEANED TOWARD THE LOWER END OF 12Z MET/MAV GUIDANCE FOR LOWS...WHICH RESULTED IN LOWERING PREVIOUS FORECAST BY 2-4 DEGREES MAINLY IN THE FAR NORTHWEST AND SOUTHERN COUNTIES. THEREFORE...AM NOW ADVERTISING LOW-MID 50S ALL AREAS...WITH TYPICAL COOLER SPOTS SUCH AS ORD AND THE PLATTE VALLEY OF WESTERN DAWSON COUNTY VERY POSSIBLY TAGGING UPPER 40S. FOR THIS TIME OF YEAR...DEFINITELY LIGHT JACKET WEATHER FOR THOSE OUT AND ABOUT LATE TONIGHT/EARLY SUNDAY MORNING. FOR THE SUNDAY DAYTIME 12Z-00Z PERIOD...LITERALLY KEPT POPS ZEROED OUT CWA-WIDE...AS A BANNER DAY WITH VERY LITTLE...IF ANY CLOUDS IS FORECAST. IN THE MID-UPPER LEVELS...THE DEPARTING SHORTWAVE WILL REACH ALL THE WAY TO THE EASTERN GREAT LAKES BY LATE AFTERNOON...WHILE THE SOUTHERN CONUS 500MB RIDGE AXIS EXPANDS NORTH AND WEST IN COVERAGE A BIT...BECOMING CENTERED FROM CO/UT TO OK/NORTHERN TX. THIS WILL LEAVE THE CWA IN FAIRLY LIGHT AND VERY DRY WEST-NORTHWEST MID LEVEL FLOW. AT THE SURFACE...THE AFOREMENTIONED RIDGE AXIS WILL START OUT CENTERED OVER THE AREA...BUT GRADUALLY SLIDE EAST TO NEAR THE MO RIVER BY LATE AFTERNOON. AS THE HIGH EDGES EAST...LIGHT SOUTHERLY BREEZES WILL GRADUALLY OVERTAKE MUCH OF THE CWA FROM WEST TO EAST...EVENTUALLY REACHING INTO THE 10-15 MPH RANGE IN FAR WESTERN COUNTIES...BUT REMAINING VERY LIGHT/NEAR CALM ALL DAY IN THE FAR EAST NEAR HWY 81. ALTHOUGH THE LIGHT BREEZES/LACK OF MIXING WILL WORK AGAINST MUCH OF A WARMUP OVER TODAY...PLENTIFUL SUNSHINE AND RELATIVELY DRY AIR WILL WORK IN FAVOR OF IT. AS HAS BEEN THE CASE FOR SEVERAL WEEKS NOW...NUMERICAL GUIDANCE HAS PROVEN DIFFICULT TO EMPLOY...WITH THE MET AVERAGING TOO WARM AND THE MAV TOO COOL. OVERALL THOUGH...WILL LEAN TOWARD THE WARMER END OF GUIDANCE...AND ESSENTIALLY JUST BUMPED UP THE PREVIOUS FORECAST 1 DEGREE. THIS YIELDS NEAR NORMAL HIGHS OF 86-88 MOST AREAS...AND 90-92 IN KS ZONES AND FURNAS COUNTY AREA. LOWERED DEWPOINTS A BIT FROM PREVIOUS FORECAST AS WELL...WITH ONLY MID-UPPER 40S SOUTHWEST AND LOW-MID 50S SOUTHEAST. ALTHOUGH RELATIVE HUMIDITY VALUES COULD DROP CLOSE TO THE 20 PERCENT CRITICAL FIRE WEATHER THRESHOLD IN A FEW FAR SOUTHWEST COUNTIES...WINDS SPEEDS WILL FALL WELL SHORT OF FIRE WEATHER CRITERIA. LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. MODELS NOT IN TOO BAD OF AGREEMENT TO START OFF THE LONG TERM PERIOD...SHOWING SUNDAY EVENING REMAINING UNDER ZONAL/WEAK NORTHWESTERLY FLOW IN THE UPPER LEVELS...A RESULT OF A BROAD HIGH PRESSURE IN PLACE ACROSS THE SCENTRAL/SWRN CONUS AND A TROUGH SHIFTING TOWARD THE EAST COAST. DURING THE OVERNIGHT HOURS...THE FLOW DOES AMPLIFY SOME AS ANOTHER TROUGH IS MAKING ITS WAY TOWARD THE WEST COAST...BUT NO NOTABLE DISTURBANCES LOOK TO MOVE THROUGH AND DECIDED TO KEEP THE FORECAST DRY. HOWEVER...MODELS DO SHOW THE SFC/LOWER LEVEL WINDS REMAINING S/SWRLY OVERNIGHT...WITH INCREASING VALUES OF ELEVATED INSTABILITY SHIFTING NORTH INTO THE REGION AS A STRONGER /30-35KT OR SO/ LLJ DEVELOPS...MAINLY ACROSS THE HIGH PLAINS REGION. THE EDGE OF THIS LLJ/INSTABILITY AXIS DOES LIE OVER THE WRN PORTIONS OF THE CWA...AND MAY HAVE TO KEEP AN EYE ON THIS AREA FOR THE POTENTIAL FOR PERHAPS SOME LIGHT PRECIP /BUT FORECAST SOUNDINGS ARE PRETTY DRY IN THE LOWER LEVELS/...OR A LITTLE MORE IN THE WAY OF CLOUD COVER. INTO MONDAY/MONDAY NIGHT...THE MAIN STORY LIES WITH THE ARRIVAL OF A MID/UPPER LEVEL WAVE...ASSOCIATED WITH A LOW PRESSURE SYSTEM LOCATED UP NEAR THE HUDSON BAY. KEPT THE DAYTIME HOURS ON MONDAY DRY...THOUGH A LITTLE MORE UNCERTAINTY ARISES TOWARD THE LATE AFTERNOON HOURS...WITH THE ACCOMPANYING SURFACE FRONTAL BOUNDARY LOOKS TO BE KNOCKING ON THE DOOR OF THE FAR NW CORNER OF THE CWA. DID RAISE POPS A BIT DURING THE EVENING/OVERNIGHT HOURS ACROSS THE N/NWRN PORTIONS OF THE CWA...BUT DIDNT MAKE MUCH CHANGE FURTHER SOUTH. AHEAD OF THE FRONT ON MONDAY...EXPECTING INCREASED SOUTHERLY WINDS...LIKELY A BIT GUSTY DURING THE AFTERNOON...AND WARMER TEMPERATURES WITH HIGHS FORECAST TO REACH INTO THE MID/UPPER 90S FOR MUCH/IF NOT ALL OF THE CWA. CONDITIONS DURING THE AFTERNOON HOURS SHOULD REMAIN BELOW CRITICAL FIRE LEVELS...RHS COULD DROP INTO THE LOWER/MID 20S ACROSS THE SOUTH...BUT SUSTAINED WIND SPEEDS ARE EXPECTED TO REMAIN <20 MPH...THOUGH GUSTS COULD AT TIMES COME CLOSE TO 25 MPH. WILL BE SOMETHING TO KEEP AN EYE ON IF MODELS HAPPEN TO TREND UP WINDS/TREND DOWN DPS. KEPT SOME LINGERING POPS IN DURING THE DAY ON TUESDAY...MAINLY ACROSS THE SRN HALF OF THE CWA...IN CLOSER PROXIMITY TO WHERE THE SFC BOUNDARY IS EXPECTED TO BE /SOMEWHERE NEAR OR SOUTH OF THE NEB AND KS STATE LINE/. CONFIDENCE NOT THE HIGHEST...AS THE PLACEMENT OF THE FRONT WILL BE DEPENDENT ON HOW THINGS PAN OUT MONDAY NIGHT. WITH MOST OF THE CWA LOOKING TO BE ON THE NORTH SIDE OF THAT BOUNDARY...MORE EASTERLY WINDS EXPECTED TO BE IN PLACE...AND FORECAST HIGHS ARE A TOUCH COOLER THAN MONDAY...MORE IN THE LOWER/MID 90S. BY 00Z WEDNESDAY...THE UPPER LEVEL PATTERN ACROSS THE CONUS HAS BECOME MORE AMPLIFIED...WITH MORE SOLIDLY NORTHWESTERLY FLOW IN PLACE ACROSS THE REGION AS THE RIDGE AXIS EXTENDS FROM THE DESERT SW THROUGH THE ROCKIES AND INTO CANADA. THE NOSE OF AN UPPER LEVEL JET STREAK ROUNDING THE TOP OF THE RIDGE AXIS IS EXPECTED TO SHIFT INTO THE REGION FROM THE NW...BRINGING THE POTENTIAL FOR MORE PRECIPITATION TUESDAY EVENING/OVERNIGHT. SIMILAR TO MONDAY/MONDAY NIGHT...WHILE THERE IS INSTABILITY IN PLACE ACROSS THE REGION...OVERALL DEEP LAYER SHEAR IS CERTAINLY NOT OUTSTANDING...GENERALLY TOPPING OUT IN THE 25-30 KTS RANGE...SO WHILE SOME THUNDERSTORMS COULD BE ON THE STRONGER SIDE...NOT EXPECTING SEVERE WEATHER AT THIS POINT. INTO WEDNESDAY...MODELS CONTINUE TO SHOW THE NOSE OF THIS UPPER LEVEL JET IN THE AREA...AND DECIDED TO KEEP SOME LINGERING POPS IN THE AREA...BUT CONFIDENCE IN CHANCES STICKING AROUND LONGER THAN PERHAPS A FEW HOURS IN THE MORNING NOT EXACTLY HIGH. THAT LOWER CONFIDENCE CONTINUES RIGHT ON THROUGH THE REMAINDER OF THE LONG TERM PERIOD. THE UPPER LEVEL PATTERN REMAINS NORTHWESTERLY ACROSS THE REGION WITH THE RIDGE STAYING IN PLACE OVER THE CENTRAL ROCKIES...AND KEPT THE FORECAST DRY AT THIS POINT...WITH MODELS SHOWING SOME DIFFERENCES WITH DISTURBANCES PASSING TO THE EAST OF THE CWA...AND WHETHER WE SEE ANY PRECIP AS RESULT. WITH THE RIDGE/WARMEST AIR REMAINING OFF TO THE WEST OF THE CWA...AND THE POTENTIAL FOR AN ADDITIONAL FRONTAL PASSAGE...NOTABLY HIGHER TEMPERATURES ARE NOT EXPECTED...WITH FORECAST HIGHS RANGING FROM ROUGHLY THE MID 90S WED/THUR TO THE MID 80S TO LOWER 90S FRI/SAT. PREV DISCUSSION... /ISSUED 1155 AM CDT SAT AUG 4 2012/ CLIMATE...TODAY/TONIGHT WILL LIKELY END UP BEING THE COOLEST DAY/NIGHT AT GRAND ISLAND AND HASTINGS IN 6.5 WEEKS. BASED ON FORECAST PROJECTIONS OVER THE NEXT FEW HOURS...THE CALENDAR DAY HIGH TEMPERATURE AT BOTH GRAND ISLAND AND HASTINGS WILL END UP SOMEWHERE BETWEEN 78-82 DEGREES...BUT IS GUARANTEED TO BE AT LEAST 78 BECAUSE THIS VALUE WAS REACHED SHORTLY AFTER MIDNIGHT BEFORE THE COLD FRONT INVADED. FOR GRAND ISLAND...A HIGH OF 79-82 DEGREES WOULD RESULT IN THE COOLEST DAILY HIGH SINCE JUNE 20TH...WHEN IT TOPPED OUT AT 79. FOR HASTINGS...A HIGH OF 78-79 DEGREES WOULD ALSO RESULT IN THE COOLEST DAY SINCE JUNE 20TH...WHEN IT REACHED 78. TURNING TO LOW TEMPERATURES TONIGHT...THE CURRENT FORECAST FOR BOTH GRAND ISLAND AND HASTINGS CALLS FOR 55. THIS IS ONLY 3 DEGREES ABOVE HASTINGS AUGUST 5TH RECORD LOW OF 52...AND 4 DEGREES ABOVE THE GRAND ISLAND RECORD LOW OF 51...BOTH SET IN 1994. ASSUMING IT DIPS TO AT LEAST 57 DEGREES OVERNIGHT...THIS WILL BE THE COOLEST LOW TEMP IN BOTH CITIES SINCE JUNE 21ST...WHEN GRAND ISLAND BOTTOMED OUT AT 52 AND HASTINGS 51. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION...EDDY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
314 AM CDT FRI AUG 3 2012 .DISCUSSION... CONVECTION MOVING THROUGH NORTH CENTRAL NEBRASKA WILL LIKELY BE ONGOING ACROSS NORTHEAST NEBRASKA THIS MORNING...AT LEAST FOR AN HOUR OR TWO...PROBABLY REMAINING JUST NORTH OF NORFOLK. OTHERWISE... CONVECTION THAT FIRED YESTERDAY EVENING HAS SENT SOME CIRRUS OVER THE FORECAST AREA...WITH ADDITIONAL BLOWOFF EXPECTED FROM ONGOING CONVECTION ACROSS WESTERN KANSAS. THIS MAKES THE HIGH TEMPERATURE FORECAST SLIGHTLY CHALLENGING TODAY...BUT FEEL WE SHOULD STILL HIT THE UPPER 90S. THE MAJORITY OF THE FORECAST ALSO REMAINS DRY TODAY...AND ADVANCE OF A COLD FRONT THAT IS EXPECTED TO MOVE THROUGH THE FORECAST AREA TONIGHT. THE EXCEPTION WILL BE NORTHEAST NEBRASKA...WHICH SHOULD SEE INCREASING CHANCES FOR STORMS BY VERY LATE THIS AFTERNOON. BETTER CHANCE FOR CONVECTION COMES THIS EVENING IN NORTHEAST NEBRASKA WHEN THUNDERSTORMS SHOULD BECOME LIKELY IN THAT AREA...PROBABLY NOT MAKING PROGRESS TOWARD THE I80 CORRIDOR UNTIL AFTER MIDNIGHT. MEANWHILE...SPOTTY CONVECTION COULD MOVE OUT OF NORTHEAST KANSAS INTO THE FAR SOUTHERN FORECAST AREA BY DAYBREAK SATURDAY...SO AREAS SOUTH OF I80 COULD STILL SEE SMALL CHANCE OF RAIN LATE FRIDAY NIGHT. FOR SATURDAY...THE MAIN FRONT WILL CONTINUE TO PUSH SOUTH OF THE REGION. HOWEVER...A SECONDARY AREA OF LIFT BEHIND THE FRONT WILL BRING A DECENT CHANCE FOR ADDITIONAL SHOWERS AND THUNDERSTORMS THAT SHOULD MOVE THROUGH THE FORECAST AREA...ALONG WITH BREEZY NORTHWEST TO NORTHERLY WINDS. TEMPERATURE FORECAST IS SOMEWHAT TRICKY SATURDAY...GIVEN COOLER READINGS BEHIND THE FRONT...ABUNDANT CLOUD CLOVER WITHIN THE SHOWERS....POTENTIAL FOR CLEARING BEHIND THE FRONT...AND ANY WARMING THAT CAN TAKE PLACE AHEAD OF THE RAINFALL. LOWER TO MID 80S...WITH THE LOWER END OF THE RANGE ALONG I80. DRY WEATHER THEN CONTINUES FOR SUNDAY AND MONDAY WITH MUCH MORE SEASONABLE TEMPERATURES ALONG WITH LOWER HUMIDITY. BY TUESDAY NIGHT AND BEYOND...FORECAST AREA REMAINS IN NORTHWESTERLY FLOW...WITH A FEW CHANCES FOR PRECIPITATION AS SUBTLE WAVES MOVE ACROSS THE AREA. DEWALD && .AVIATION...06Z TAFS FOR KOMA...KLNK...KOFK. VFR CONDITIONS SHOULD PREVAIL THROUGH THE NEXT 24 HOURS. MID AND HIGH LEVEL MOISTURE WILL SPREAD OVER THE TAF SITES DURING NIGHT. TSRA CURRENTLY MOVING E/SE ACROSS SOUTHERN SD COULD APPROACH KOFK LATE TONIGHT...BUT 01Z RUN OF HRRR MODEL SHOWED THESE WEAKENING TOWARD SUNRISE. WINDS WILL TURN TO THE SOUTH/SOUTHEAST AND INCREASE ON FRIDAY...AHEAD OF THE NEXT COLD FRONT. THUNDERSTORMS COULD AFFECT PARTS OF NORTHEAST NEBRASKA BY FRIDAY EVENING. DID NOT INCLUDE WITH THIS ISSUANCE...BUT MENTION OF TSRA MAY BE NEEDED AT KOFK AFTER 00Z SATURDAY. MILLER && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1222 AM CDT FRI AUG 3 2012 .AVIATION...06Z TAF. THUNDERSTORMS TO THE WEST HAVE ALLOWED FOR SOME HIGH CLOUDS TO MOVE ACROSS THE KGRI TERMINAL EARLY THIS MORNING. THE THUNDERSTORMS HAVE SINCE DIED OFF AND EXPECT DRY CONDITIONS THROUGH THE NIGHT. THE SURFACE GRADIENT TIGHTENS DURING THE DAY ON FRIDAY AND ALLOWS FOR WINDS FROM THE SOUTH TO INCREASE SOME. DURING THE EVENING HOURS ON FRIDAY A COLD FRONT APPROACHES AND WITH IT THERE ARE SOME THUNDERSTORMS POSSIBLE LATE IN THE PERIOD. SINCE IT IS A BROAD LOW PRESSURE SYSTEM AND FRONT THE WINDS WILL BE LIGHT AND TURN VERY GRADUALLY. && .PREV DISCUSSION... /ISSUED 333 PM CDT THU AUG 2 2012/ SHORT TERM...TONIGHT THROUGH FRIDAY AFTERNOON. CONCERN IN THE NEXT 24 HRS WILL BE SLIGHT CHANCES FOR TSTMS EARLY ON ALONG WITH HIGH TEMPERATURES FOR FRIDAY. CURRENT WATER VAPOR IMAGERY ALONG WITH UPPER AIR AND WIND PROFILER DATA SHOW UPPER RIDGE NOW ANCHORED OVER TEXAS...AN UPPER LOW DROPPING SSE AND INTO THE WESTERN PART OF ALBERTA...PUTTING THE PLAINS IN WESTERLY FLOW. ONE CAN ALSO SEE THE SUBTROPICAL MOISTURE TAP STREAMING NORTH ACROSS WESTERN MEXICO...INTO THE FOUR CORNERS REGION AND THEN SWINGING EAST AROUND THE HIGH ACROSS OUR REGION. AT THE SURFACE...PRESSURE GRADIENT VERY WEAK ACROSS NEB/KS WITH ONE WEAK SURFACE LOW OVER OKLAHOMA AND ANOTHER ONE SITUATED ACROSS EASTERN MT/WY. SURFACE DEWPOINTS REMAIN FAIRLY HIGH OVER THE CWA RANGING FROM THE MID TO UPPER 60S AT LUNCHTIME. WEAK CONVECTIVE ACTIVITY HAS NEVER QUITE FADED AWAY IN OUR KS CWA ALTHOUGH DOUBT ANYTHING IS REACHING THE GROUND. CLOUD COVER ACROSS OUR SOUTHERN CWA HAS BEEN HOLDING IN A LITTLE LONGER THAN ANTICIPATED AND WITH SOME RE-DEVELOPMENT TO THE WEST...MAY NOT SEE HIGHS QUITE AS WARM AS EXPECT. ALSO WEAK CELLS MOVING ACROSS NORTHERN NEBRASKA HAVE ALSO HUNG IN DURING THE DAY. SOME OF THE HOURLY HRRR MODEL RUNS HAVE SHOWN THIS HANGING TOGETHER AND MOVING INTO THE WESTERN PART OF THE CWA LATER THIS AFTERNOON. WILL NEED TO MONITOR THIS OVER THE NEXT FEW HOURS. BELIEVE OUR BETTER...ALTHOUGH NOT GREAT...CHANCES FOR RAIN WILL BE LATER THIS EVENING AND OVERNIGHT. CHECKING OUT THE NEEDED INGREDIENTS...WE HAVE ADEQUATE INSTABILITY...MOISTURE AND SHEAR AT PRESENT BUT SEEM TO BE LACKING A FORCING MECHANISM. BELIEVE THE SURFACE TROUGH ALONG THE FRONT RANGE MAY FIT THE BILL AND WILL MONITOR CONVECTIVE DEVELOPMENT OUT WEST LATER THIS AFTERNOON. QUESTION THEN BECOMES WILL THIS ACTIVITY MAKE IT FAR ENOUGH EAST TO AFFECT OUR CWA. EARLY LOOK AT HRRR SHOWS THIS IS POSSIBLE AND WILL CHECK OUT THE 4KM WRF WHEN IT ARRIVES. SEEMS LIKE BETTER LOW LEVEL JET REMAINS WEST OVERNIGHT. ON FRIDAY AFTERNOON...THE UPPER LOW NOTED ABOVE WILL SHOULD BE CENTERED SOMEWHERE NEAR THE MT/NDAK/CANADA BORDER. THIS IS A DECENT WAVE AND SHOULD PROVIDE GOOD HEIGHT FALLS AND COOLER TEMPS ALOFT TO THE NORTHERN PLAINS. IT WILL ALSO PUSH A COLD FRONT INTO OUR NW CWA BY LATE AFTN OR EARLY EVENING. EXPECT SOME COMPRESSIONAL HEATING AHEAD OF THE FRONT AND WITH SURFACE WINDS BECOMING SOUTH TO SSW ANOTHER HOT DAY WILL BE IN STORE. DO NOT PLAN ON ISSUING ANY HEAT HEADLINES AS APPARENT TEMPERATURE VALUES FORECAST TO BE BETWEEN 98 AND 102 DEGREES IN THE SOUTHERN CWA. NOT SURE IF CONVECTION WILL BREAK OUT LATE FRIDAY AFTERNOON OR HOLD OFF UNTIL THE EVENING AS MOST MODELS SHOWING THE BULK OF THE PRECIPITATION BEING POST FRONTAL. IF I DO PUT IN AFTERNOON POPS...IT WILL MAINLY BE IN THE NORTHWEST AND WEST PART OF THE CWA. LONG TERM...FRIDAY NIGHT THROUGH THURSDAY. CONCERNS FOR THE MID AND LONG TERM PERIOD WILL AGAIN FOCUS ON CHANCES FOR THUNDERSTORMS AS WELL AS COOLER TEMPERATURES FOR THE WEEKEND. BEGINNING THE MID TERM PERIOD...THE MODELS REMAIN IN FAIRLY CONSISTENT AGREEMENT AS THE UPPER LEVEL LOW CONTINUES TO SHIFT EASTWARD ACROSS PORTIONS OF MONTANA AND NORTH DAKOTA. AT THE SURFACE...A LARGE AREA OF LOW PRESSURE ALSO CONTINUES TO PUSH EASTWARD...WITH AN ASSOCIATED COLD FRONTAL BOUNDARY KNOCKING ON OUR DOORSTEP BY FRIDAY EVENING. THUNDERSTORM CHANCES CONTINUE INTO THE OVERNIGHT HOURS...WITH THE POSSIBILITY OF A FEW STRONG STORMS IN THE EARLY EVENING. BY LATE SATURDAY MORNING...THE FRONTAL BOUNDARY SHOULD BEGIN TO SAG SOUTHEAST OUT OF THE REGION WITH LINGERING SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS ALONG THE ELEVATED BOUNDARY. WITH FRONTAL PASSAGE OVERNIGHT FRIDAY...HIGH PRESSURE AND COOLER TEMPERATURES WILL SINK INTO THE REGION ALONG WITH NORTH WINDS. MUCH COOLER 850 TEMPERATURES ON THE ORDER OF 10 DEGREES COOLER THAN PREVIOUS DAYS WILL HELP DRASTICALLY REDUCE HIGH TEMPERATURES. A VERY NICE WEEKEND IS IN STORE WITH HIGHS IN THE MID TO UPPER 80S. BY THE BEGINNING OF THE WORKWEEK...THE UPPER LEVEL RIDGE WILL BEGIN TO BUILD BACK IN ACROSS THE ROCKIES...RESULTING IN NORTHWEST FLOW THROUGH THE EXTENDED PERIOD. A DRY FORECAST IS EXPECTED THROUGH THE BEGINNING OF THE WORKWEEK AS THE CENTRAL PLAINS REMAIN UNDER SURFACE HIGH PRESSURE. HOWEVER...TOWARDS THE END OF THE PERIOD...A FEW SHORT WAVE PERTURBATIONS ROUND THE EASTERN EDGE OF THE UPPER LEVEL RIDGE...AND COMBINED WITH A SURFACE TROUGH AXIS ALONG THE FRONT RANGE WILL HELP GENERATE SOME CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED. CONTINUED SLIGHT CHANCES THROUGH THE PERIOD...MONDAY AND AGAIN TUESDAY NIGHT THROUGH WEDNESDAY. AS FOR TEMPERATURES...ALTHOUGH MUCH OF THE WARMER 850 TEMPERATURES REMAIN FARTHER WEST ACROSS THE ROCKIES...EXPECT A RISE IN TEMPERATURES THROUGH THE WORKWEEK. CONTINUED WITH HIGHS IN THE MID TO UPPER 90S. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1140 PM CDT THU AUG 2 2012 .AVIATION... 06Z TAFS FOR KOMA...KLNK...KOFK. VFR CONDITIONS SHOULD PREVAIL THROUGH THE NEXT 24 HOURS. MID AND HIGH LEVEL MOISTURE WILL SPREAD OVER THE TAF SITES DURING NIGHT. TSRA CURRENTLY MOVING E/SE ACROSS SOUTHERN SD COULD APPROACH KOFK LATE TONIGHT...BUT 01Z RUN OF HRRR MODEL SHOWED THESE WEAKENING TOWARD SUNRISE. WINDS WILL TURN TO THE SOUTH/SOUTHEAST AND INCREASE ON FRIDAY...AHEAD OF THE NEXT COLD FRONT. THUNDERSTORMS COULD AFFECT PARTS OF NORTHEAST NEBRASKA BY FRIDAY EVENING. DID NOT INCLUDE WITH THIS ISSUANCE...BUT MENTION OF TSRA MAY BE NEEDED AT KOFK AFTER 00Z SATURDAY. MILLER && .PREV DISCUSSION... /ISSUED 314 PM CDT THU AUG 2 2012/ DISCUSSION... SYNOPSIS...12Z UPPER AIR ANALYSIS INDCD NEXT MAIN SYSTEM OF INTERESTED WAS DIVING SEWD THROUGH AB AND BC ASSOCIATED WITH AN 90 KT H3 JET AND 70 M H5 HEIGHT FALLS. DOWNSTREAM FM THAT SYSTEM...A WEAK SHRTWV TROF WAS NOTED OVER MN ASSOCIATED WITH A COOL FNT AT H85 FM MN INTO ERN NEB. 19Z SFC ANLYS INDCD 1008 MB LOW PRESSURE OVER SRN IA WITH CDFNT FM NRN MO INTO SRN KS. FORECAST...THE MAIN STORY OVER THE NEXT 36 HRS WILL BE THE EFFECTS OF THE CANADIAN SYSTEM AS IT DROPS INTO THE CNTRL US. FOR TONIGHT WEAK SURFACE HIGH PRESSURE WILL CROSS THE AREA THIS EVENING WITH AFTN CU FIELD GIVING WAY TO MOSTLY CLEAR SKIES. LOW LEVEL WAA OVER THE HIGH PLAINS WILL SHIFT EWD INTO NRN NEB AFTER MIDNIGHT AND MAY ALLOW FOR AN ISOLATED SHOWER TO CLIP OUR FAR NW FA AND LEFT A SCHC POP THERE. SFC WINDS WILL TURN S/SE ON FRI AHEAD OF THE STRONG CDFNT AND ASSOCIATED UPPER LEVEL SYSTEM. NAM CERTAINLY MIXES OUT OUR BOUNDARY LAYER TO MUCH...BUT GIVEN 850 TMPS OFF THE NAM/GFS...HIGHS SHOULD CLIMB TO AROUND 100 ON FRI AFTN. ALTHOUGH THE ATMOSPHERE WILL BE STRONGLY CAPPED ON FRI AS ELEVATED MIXED LAYER /SEEN IN THE +14 C H7 TMPS/ SPREADS OVER THE FA...CONVERGENCE ALONG THE COLD FRONT AND SOME UPPER LEVEL SUPPORT ASSOCIATED WITH IN THE INCOMING JET SHOULD ALLOW FOR SCT TSRA TO DVLP FM ERN SD INTO NRN NEB...AND THESE WILL MAKE A PUSH TOWARD AREA NW FA ON FRI EVNG WITH HIGH CHC POPS WARRANTED. AS WAS THE CASE LAST NIGHT...THESE STORMS WILL LOSE SOME INTENSITY WITH THE COOLING BOUNDARY LAYER AND LOSS OF UPPER LEVEL SUPPORT THE FURTHER S THEY PUSH...AND THUS THE CNTRL AND SRN CWA HAVE A MUCH LOWER CHC OF SEEING RAINFALL. THE SFC CDFNT WILL PUSH THRU THE SRN CWA ON SAT MRNG WITH CAA KICKING IN FOR THE REST OF SAT. AT THE SAME TIME THE MAIN UPPER LEVEL TROUGH WILL BE PUSHING THRU SD WITH DECENT DPVA INDICATED IN THE MODELS ALONG WITH STRONG H7 FRONTOGENESIS. THIS SHOULD LEAD TO A FEW SHOWERS THROUGH THE MRNG...AND MAYBE EARLY AFTERNOON OVER NRN CWA AS THE FORCING MOVES THROUGH. OTHERWISE THERE MAY BE A TSRA OR TWO DEVELOP NEAR OR SLIGHTLY BEHIND THE FNT OVER FAR SE NEB/SW IA ON SAT AFTN. OTHERWISE WITH THE CAA AND SOME CLOUDS WE ARE EXPECTING MUCH COOLER HIGHS ON SAT! EXTENDED...THE COOLER AND DRY WEATHER WILL CONT FOR SUN/MON WITH HIGHS IN THE 80S AND LOWS IN THE 60S...BEFORE A WARMING TREND GETS GOING WITH HIGHS BACK INTO THE 90S FOR TUE-THU. MODELS SEEM FAIRLY CONSISTENT ON TAKING A SHORTWAVE TROUGH OVER THE RIDGE ON TUE NIGHT/WE AND WE HAVE SOME CHC POPS GOING FOR THIS PERIOD. BOUSTEAD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
409 PM EDT FRI AUG 3 2012 .SYNOPSIS... A WEAK COLD FRONT WILL DROP SOUTH ACROSS THE AREA THIS EVENING...ACCOMPANIED BY A SMALL CHANCE FOR THUNDERSTORMS THROUGH EARLY EVENING. MAINLY DRY HOT WEATHER WILL RETURN ON SATURDAY. A STRONGER COLD FRONT WILL BRING A BETTER CHANCE OF THUNDERSTORMS ON SUNDAY... FOLLOWED BY COOLER DRY WEATHER ON MONDAY. && .NEAR TERM /THROUGH SATURDAY/... 4 PM UPDATE...MAINLY SKC ACRS THWEBGM FCST AREA WITH XCPTN OF SOME MID/HI CLD ACRS THE FINGER LAKES AND FAR SE ZONES. WSR-88D SHOWS A WEAK E-W BNDRY BNDRY FROM SRN SCHUYLER/TOMKINS ACRS NRN BROOME INTO SRN CHENANGO CNTY. HOWEVER...TD`S ARE LOWEST ACRS THE SRN TIER AND ANY LOW LVL CONVERGENCE WILL BE WEAK DUE TO THE LGT WINDS VCNTY OF THE BNDRY. LACK OF UPR DYNAMICS AND LOW LVL CIN CONTINUE TO IMPEDE DVLPMNT. GIVEN THESE TRENDS...WE LOWERED POPS TO SLGT CHC FOR LATE THIS AFTN/EVNG AND LOWERED SKY CVR. PREV BLO... 2 PM UPDATE...NOT MUCH GOING ON ATTM ON RADAR AND WITH A BIT OF A MID LEVEL CAP BETWEEN H8 AND H9 MB....A LOT OF US ARE NOT EVEN SEEING A CU FIELD FORM. THE EXCEPTION IS ACROSS WESTERN NY NEAR KROC SOUTHEAST THROUGH THE FINGER LAKES. THIS AREA IS RIGHT AHEAD OF A COLD FRONT THAT IS WASHING OUT OVER CNY. THIS CU FIELD MATCHES UP QUITE WELL WITH THE NAM 12 AND LATEST HRRR WHICH CONTINUES TO SHOW ISOLATED CONVECTION DEVELOPING THROUGH 21Z ACROSS THE FINGER LAKES...THROUGH THE SOUTHERN TIER INTO NORTHERN PA. CONTINUED TO PLAY SLIGHT CHANCE POPS OVERALL THROUGH EVENING...BUT HIGHLIGHT THE AREAS MENTIONED ABOVE FOR A CHANCE OF A FEW ISOLATED STORMS. SEVERE STORMS ARE NOT EXPECTED GIVEN WEAK MID LEVEL SHEAR (0-6 KM LESS THAN 20 KTS)...BUT BRIEF GUSTY WINDS (DOWNBURSTS) A POSSIBILITY GIVEN SBCAPES IN THE 1000-2000 J/KG RANGE AND AN INVERTED V SOUNDING. WHAT CONVECTION WE SEE THIS EVENING WILL DIMINISH QUICKLY THIS EVENING. WE WILL AGAIN BE IN A RICH ENVIRONMENT SATURDAY WITH MLCAPES IN THE 1000-2000 J/KG RANGE BUT WE WILL AGAIN BE LACKING A TRIGGER. THE FRONT WHICH WILL CAUSE SOME ACTION THIS EVENING...WILL BE WASHED OUT. ANY UPPER LEVEL SUPPORT LOOKS TO STAY NORTH OF OUR CWA AS THE UPPER LEVEL FLOW BECOMES MORE SOUTHWESTERLY. CONTINUED WITH THE MENTIONED OF ISOLATED CONVECTION AS WE MAY HAVE SOME LEFTOVER BOUNDARIES FROM TODAY BUT MOST WILL REMAIN DRY. THE BIGGEST STORY SATURDAY WILL AGAIN BE HOT TEMPS WITH HIGHS WELL INTO THE 90S. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... DEEP S-SWLY FLOW WILL BECOME ESTABLISHED OVER THE REGION ON SATURDAY NIGHT AS SIGNIFICANT UPPER TROF PLOWS THROUGH THE GTLKS REGION. OVERALL...WILL FOLLOW THE NAM AND ECMWF SOLUTIONS DURING THIS TIME AS GFS LOOKS A LITTLE AGGRESSIVE IN DEVELOPING CONVECTION WELL OUT AHEAD OF THE MAIN TROF WITHOUT MUCH FORCING. THAT SAID...WILL CARRY SOME SMALL CHANCES FOR TSRA ACROSS THE SOUTHERN PART OF FCST AREA AS BEGINNINGS OF HEIGHT FALLS AND POTENTIAL FOR AN EMBEDDED MINOR WAVE COMING OUT OF PENNSYLVANIA COULD SPAWN SOME LATE NIGHT ACTIVITY AND THE 12KM NAM IS SUGGESTING SOME ACTIVITY IN CNTRL PA WORKING NORTH FROM 03Z-09Z. ON SUNDAY...DESTABILIZATION OF THE LOWER TROPOSPHERE WILL CONTINUE...MAINLY DUE TO THE INFLUX OF LOW LEVEL MOISTURE AS OPPOSED TO A LOT OF PRISTINE SOLAR HEATING HOURS. CNY/NEPA REGION SHOULD START THE DAY OFF PRETTY JUNKED UP WITH LOW LVL CLOUDINESS AS A RESULT OF WARM AND MOIST ADVECTIONS SAT NIGHT. BREAKS IN CLOUDS ARE EXPECTED LATER ON WITH OVERALL MEAN LYR CAPE VALUES RANGING IN THE 1000-1500 J/KG RANGE. WITH SUCH A DYNAMIC UPPER SYSTEM APPROACHING...THIS IS MORE THAN ENOUGH ENERGY. 0-3 KM AND 0-1 KM BULK SHEAR VALUES ARE FCST IN THE 25-30 KT RANGE IN A VERTICALLY LAMINAR FASHION. THE MODEL TRENDS CONTINUE TO SLOW THE PASSAGE OF THE ACTUAL SFC FRONT DOWN TO LATE SUNDAY NIGHT...HOWEVER REGIME OF 500 MB HEIGHT FALLS AND BEST JET DIVERGENCE ARE EXPECTED TO COINCIDE OVER CNY/NEPA DURING THE LATE AFTERNOON AND EVENING HOURS. AT THIS TIME...THE PARAMETERS SUGGEST A LINEAR CONVECTIVE MODE OF MULTICELLS AND LINES WITH WIND DAMAGE THE HIGHEST CONCERN. HEADING INTO MONDAY...THE FRONT AND UPPER TROF AXIS CLEARS THE REGION SHORTLY BEFORE 12Z WITH COOLER AND DRIER HIGH PRESSURE TO FOLLOW. HAVE REDUCED POPS ON MONDAY TO JUST THE EARLIEST FEW HOURS AROUND 12Z...AND THAT STILL MAY BE A BIT TOO MUCH WITH MOST MODEL TRENDS SUGGESTING THAT DEEP MOISTURE AND FORCING WILL BE EAST OF THE REGION. CLOUDS MAY LIMIT TEMPS A BIT ON SUNDAY...BUT STILL EXPECT TO BE WELL INTO THE 80S AFTER A PRETTY MILD AND MUGGY START TO THE DAY. IT SHOULD FEEL RATHER OPPRESSIVE WITH FCST DWPTS REACHING THE LOWER 70S ON SUNDAY...BUT WITHOUT TEMPERATURES SURGING INTO THE 90S THE DANGER FROM EXCESSIVE HEAT IS NOT ANTICIPATED. COOLER...DRIER AND MORE SEASONABLE CONDITIONS ARE FORECAST MONDAY AND GENERALLY FOLLOWED BLENDED MOS GUIDANCE TRENDS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... HIGH PRESSURE LINGERS OVER THE REGION THROUGH TUESDAY...WHICH WILL THEN BE FOLLOWED BY ANOTHER WEAK COLD FRONT AND BROAD UPPER TROF DRIFTING INTO THE REGION FROM WEDNESDAY THROUGH FRIDAY. THESE FEATURES WILL LIKELY ACT AS THE FOCUS FOR SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY DRIVEN BY DIURNAL INFLUENCES. THE LATEST GFS AND LAST NIGHT/S ECMWF DEFINITELY DIFFER ON SOLUTIONS FOR THIS PERIOD WITH THE ECMWF ILLUSTRATING A STRONGER TROF PASSAGE THROUGH THE EAST THURSDAY NIGHT INTO FRIDAY. HPC THINKS THIS HAS LITTLE SUPPORT WITHIN THE GENERAL ENSEMBLE FORECASTS AND WILL LEAN WITH THEIR GENTLER APPROACH. ENSEMBLE THERMAL FORECASTS AT 850 MB SHOW NO ANOMALOUS DEVIATIONS... THEREFORE WILL FOLLOW A BLEND OF HPC AND MOS GUIDANCE ON TEMPERATURES WHICH SHOULD TURN OUT TO BE FAIRLY NORMAL. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... 145 PM UPDATE... GENERALLY VFR THROUGH THE END OF THE TAF PERIOD...WITH A LOW CHANCE AT MVFR VSBYS IN CONVECTION EARLY THIS EVENING...AND AGAIN NEAR DAYBREAK DUE TO HAZE. A COLD FRONT NOW JUST OVER WESTERN NY IS IN THE PROCESS OF FALLING APART AS IT ENTERS OUR TERMINALS. WITH A RICH ENVIRONMENT AHEAD OF THIS FRONT CONVECTION CAN`T BE RULED OUT. HOWEVER WITHOUT STRONG UPPER LEVEL SUPPORT...ANYTHING THAT FORMS IS EXPECTED TO BE FAIRLY ISOLATED. EVEN THOUGH WE ARE CLOSE TO THE TIME OF INITIATION (19Z - 0Z)...COVERAGE STILL EXPECTED TO BE TOO ISOLATED TO INCLUDE IN THE TAFS. MID AND HIGH CLOUDS EXPECTED FROM LATE THIS AFTERNOON THROUGH TONIGHT. NEAR DAYBREAK SATURDAY MOST OF THE MODEL GUIDANCE INDICATES MVFR VSBYS IN HAZE AT ALL SITES. AGREE WITH THE PREVIOUS FORECASTER THAT THE TEMP/DEW POINT SPREAD APPEARS TO BE TOO GREAT FOR A HAZY NIGHT. IF WE WERE TO SEE HAZE KELM STILL STANDS THE BEST SHOT AND LEFT A TEMPO GROUP IN TO COVER THAT. WINDS SOUTH TO SOUTHWEST 5 TO 10 KTS THIS AFTERNOON...BECOMING L/V OR LIGHT SOUTH TONIGHT. THE GRADIENT IS A BIT STRONGER SATURDAY WHICH WILL PRODUCE SOUTH TO SOUTHWEST WINDS NEAR 10 KTS...WITH GUSTS TOWARD 20 POSSIBLE ESPECIALLY BY AFTERNOON. OUTLOOK... SAT AFTERNOON THROUGH SUN MORNING...VFR MUCH OF THE TIME. ISOLD- SCTD LATE AFTN/EARLY EVE TSRA PSBL...WITH BRIEF RESTRICTIONS. ALSO MVFR VSBYS POSSIBLE SUN AM DUE TO HAZE. SUNDAY AFTERNOON THROUGH SUNDAY EVENING...A COLD FRONT PASSING THROUGH THE REGION WILL PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS WITH MVFR/IFR RESTRICTIONS IN STORMS. MON - WED...AT THIS EARLY VANTAGE PT...PRIMARILY VFR ANTICIPATED. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...JAB NEAR TERM... SHORT TERM...JAB LONG TERM...JAB AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
246 PM EDT FRI AUG 3 2012 .SYNOPSIS... A WEAK COLD FRONT WILL DROP SOUTH ACROSS THE AREA THIS EVENING...ACCOMPANIED BY A SMALL CHANCE FOR THUNDERSTORMS THROUGH EARLY EVENING. MAINLY DRY HOT WEATHER WILL RETURN ON SATURDAY. A STRONGER COLD FRONT WILL BRING A BETTER CHANCE OF THUNDERSTORMS ON SUNDAY... FOLLOWED BY COOLER DRY WEATHER ON MONDAY. && .NEAR TERM /THROUGH SATURDAY/... 2 PM UPDATE...NOT MUCH GOING ON ATTM ON RADAR AND WITH A BIT OF A MID LEVEL CAP BETWEEN H8 AND H9 MB....A LOT OF US ARE NOT EVEN SEEING A CU FIELD FORM. THE EXCEPTION IS ACROSS WESTERN NY NEAR KROC SOUTHEAST THROUGH THE FINGER LAKES. THIS AREA IS RIGHT AHEAD OF A COLD FRONT THAT IS WASHING OUT OVER CNY. THIS CU FIELD MATCHES UP QUITE WELL WITH THE NAM 12 AND LATEST HRRR WHICH CONTINUES TO SHOW ISOLATED CONVECTION DEVELOPING THROUGH 21Z ACROSS THE FINGER LAKES...THROUGH THE SOUTHERN TIER INTO NORTHERN PA. CONTINUED TO PLAY SLIGHT CHANCE POPS OVERALL THROUGH EVENING...BUT HIGHLIGHT THE AREAS MENTIONED ABOVE FOR A CHANCE OF A FEW ISOLATED STORMS. SEVERE STORMS ARE NOT EXPECTED GIVEN WEAK MID LEVEL SHEAR (0-6 KM LESS THAN 20 KTS)...BUT BRIEF GUSTY WINDS (DOWNBURSTS) A POSSIBILITY GIVEN SBCAPES IN THE 1000-2000 J/KG RANGE AND AN INVERTED V SOUNDING. WHAT CONVECTION WE SEE THIS EVENING WILL DIMINISH QUICKLY THIS EVENING. WE WILL AGAIN BE IN A RICH ENVIRONMENT SATURDAY WITH MLCAPES IN THE 1000-2000 J/KG RANGE BUT WE WILL AGAIN BE LACKING A TRIGGER. THE FRONT WHICH WILL CAUSE SOME ACTION THIS EVENING...WILL BE WASHED OUT. ANY UPPER LEVEL SUPPORT LOOKS TO STAY NORTH OF OUR CWA AS THE UPPER LEVEL FLOW BECOMES MORE SOUTHWESTERLY. CONTINUED WITH THE MENTIONED OF ISOLATED CONVECTION AS WE MAY HAVE SOME LEFTOVER BOUNDARIES FROM TODAY BUT MOST WILL REMAIN DRY. THE BIGGEST STORY SATURDAY WILL AGAIN BE HOT TEMPS WITH HIGHS WELL INTO THE 90S. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... DEEP S-SWLY FLOW WILL BECOME ESTABLISHED OVER THE REGION ON SATURDAY NIGHT AS SIGNIFICANT UPPER TROF PLOWS THROUGH THE GTLKS REGION. OVERALL...WILL FOLLOW THE NAM AND ECMWF SOLUTIONS DURING THIS TIME AS GFS LOOKS A LITTLE AGGRESSIVE IN DEVELOPING CONVECTION WELL OUT AHEAD OF THE MAIN TROF WITHOUT MUCH FORCING. THAT SAID...WILL CARRY SOME SMALL CHANCES FOR TSRA ACROSS THE SOUTHERN PART OF FCST AREA AS BEGINNINGS OF HEIGHT FALLS AND POTENTIAL FOR AN EMBEDDED MINOR WAVE COMING OUT OF PENNSYLVANIA COULD SPAWN SOME LATE NIGHT ACTIVITY AND THE 12KM NAM IS SUGGESTING SOME ACTIVITY IN CNTRL PA WORKING NORTH FROM 03Z-09Z. ON SUNDAY...DESTABILIZATION OF THE LOWER TROPOSPHERE WILL CONTINUE...MAINLY DUE TO THE INFLUX OF LOW LEVEL MOISTURE AS OPPOSED TO A LOT OF PRISTINE SOLAR HEATING HOURS. CNY/NEPA REGION SHOULD START THE DAY OFF PRETTY JUNKED UP WITH LOW LVL CLOUDINESS AS A RESULT OF WARM AND MOIST ADVECTIONS SAT NIGHT. BREAKS IN CLOUDS ARE EXPECTED LATER ON WITH OVERALL MEAN LYR CAPE VALUES RANGING IN THE 1000-1500 J/KG RANGE. WITH SUCH A DYNAMIC UPPER SYSTEM APPROACHING...THIS IS MORE THAN ENOUGH ENERGY. 0-3 KM AND 0-1 KM BULK SHEAR VALUES ARE FCST IN THE 25-30 KT RANGE IN A VERTICALLY LAMINAR FASHION. THE MODEL TRENDS CONTINUE TO SLOW THE PASSAGE OF THE ACTUAL SFC FRONT DOWN TO LATE SUNDAY NIGHT...HOWEVER REGIME OF 500 MB HEIGHT FALLS AND BEST JET DIVERGENCE ARE EXPECTED TO COINCIDE OVER CNY/NEPA DURING THE LATE AFTERNOON AND EVENING HOURS. AT THIS TIME...THE PARAMETERS SUGGEST A LINEAR CONVECTIVE MODE OF MULTICELLS AND LINES WITH WIND DAMAGE THE HIGHEST CONCERN. HEADING INTO MONDAY...THE FRONT AND UPPER TROF AXIS CLEARS THE REGION SHORTLY BEFORE 12Z WITH COOLER AND DRIER HIGH PRESSURE TO FOLLOW. HAVE REDUCED POPS ON MONDAY TO JUST THE EARLIEST FEW HOURS AROUND 12Z...AND THAT STILL MAY BE A BIT TOO MUCH WITH MOST MODEL TRENDS SUGGESTING THAT DEEP MOISTURE AND FORCING WILL BE EAST OF THE REGION. CLOUDS MAY LIMIT TEMPS A BIT ON SUNDAY...BUT STILL EXPECT TO BE WELL INTO THE 80S AFTER A PRETTY MILD AND MUGGY START TO THE DAY. IT SHOULD FEEL RATHER OPPRESSIVE WITH FCST DWPTS REACHING THE LOWER 70S ON SUNDAY...BUT WITHOUT TEMPERATURES SURGING INTO THE 90S THE DANGER FROM EXCESSIVE HEAT IS NOT ANTICIPATED. COOLER...DRIER AND MORE SEASONABLE CONDITIONS ARE FORECAST MONDAY AND GENERALLY FOLLOWED BLENDED MOS GUIDANCE TRENDS. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE LINGERS OVER THE REGION THROUGH TUESDAY...WHICH WILL THEN BE FOLLOWED BY ANOTHER WEAK COLD FRONT AND BROAD UPPER TROF DRIFTING INTO THE REGION FROM WEDNESDAY THROUGH FRIDAY. THESE FEATURES WILL LIKELY ACT AS THE FOCUS FOR SOME SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY DRIVEN BY DIURNAL INFLUENCES. THE LATEST GFS AND LAST NIGHT/S ECMWF DEFINITELY DIFFER ON SOLUTIONS FOR THIS PERIOD WITH THE ECMWF ILLUSTRATING A STRONGER TROF PASSAGE THROUGH THE EAST THURSDAY NIGHT INTO FRIDAY. HPC THINKS THIS HAS LITTLE SUPPORT WITHIN THE GENERAL ENSEMBLE FORECASTS AND WILL LEAN WITH THEIR GENTLER APPROACH. ENSEMBLE THERMAL FORECASTS AT 850 MB SHOW NO ANOMALOUS DEVIATIONS... THEREFORE WILL FOLLOW A BLEND OF HPC AND MOS GUIDANCE ON TEMPERATURES WHICH SHOULD TURN OUT TO BE FAIRLY NORMAL. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... 145 PM UPDATE... GENERALLY VFR THROUGH THE END OF THE TAF PERIOD...WITH A LOW CHANCE AT MVFR VSBYS IN CONVECTION EARLY THIS EVENING...AND AGAIN NEAR DAYBREAK DUE TO HAZE. A COLD FRONT NOW JUST OVER WESTERN NY IS IN THE PROCESS OF FALLING APART AS IT ENTERS OUR TERMINALS. WITH A RICH ENVIRONMENT AHEAD OF THIS FRONT CONVECTION CAN`T BE RULED OUT. HOWEVER WITHOUT STRONG UPPER LEVEL SUPPORT...ANYTHING THAT FORMS IS EXPECTED TO BE FAIRLY ISOLATED. EVEN THOUGH WE ARE CLOSE TO THE TIME OF INITIATION (19Z - 0Z)...COVERAGE STILL EXPECTED TO BE TOO ISOLATED TO INCLUDE IN THE TAFS. MID AND HIGH CLOUDS EXPECTED FROM LATE THIS AFTERNOON THROUGH TONIGHT. NEAR DAYBREAK SATURDAY MOST OF THE MODEL GUIDANCE INDICATES MVFR VSBYS IN HAZE AT ALL SITES. AGREE WITH THE PREVIOUS FORECASTER THAT THE TEMP/DEW POINT SPREAD APPEARS TO BE TOO GREAT FOR A HAZY NIGHT. IF WE WERE TO SEE HAZE KELM STILL STANDS THE BEST SHOT AND LEFT A TEMPO GROUP IN TO COVER THAT. WINDS SOUTH TO SOUTHWEST 5 TO 10 KTS THIS AFTERNOON...BECOMING L/V OR LIGHT SOUTH TONIGHT. THE GRADIENT IS A BIT STRONGER SATURDAY WHICH WILL PRODUCE SOUTH TO SOUTHWEST WINDS NEAR 10 KTS...WITH GUSTS TOWARD 20 POSSIBLE ESPECIALLY BY AFTERNOON. OUTLOOK... SAT AFTERNOON THROUGH SUN MORNING...VFR MUCH OF THE TIME. ISOLD- SCTD LATE AFTN/EARLY EVE TSRA PSBL...WITH BRIEF RESTRICTIONS. ALSO MVFR VSBYS POSSIBLE SUN AM DUE TO HAZE. SUNDAY AFTERNOON THROUGH SUNDAY EVENING...A COLD FRONT PASSING THROUGH THE REGION WILL PRODUCE WIDESPREAD SHOWERS AND THUNDERSTORMS WITH MVFR/IFR RESTRICTIONS IN STORMS. MON - WED...AT THIS EARLY VANTAGE PT...PRIMARILY VFR ANTICIPATED. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...HEDEN NEAR TERM...HEDEN SHORT TERM...JAB LONG TERM...JAB AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1021 PM EDT SAT AUG 4 2012 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL BRING TYPICAL SUMMER-TIME WEATHER THROUGH THE WEEKEND...WITH NEAR NORMAL TEMPERATURES AND ISOLATED TO SCATTERED THUNDERSTORMS. A WEAK TROPICAL WAVE MOVING INTO FLORIDA COULD BRING COASTAL SHOWERS SUNDAY AND MONDAY. TROPICAL MOISTURE FROM THE GULF OF MEXICO WILL BRING HUMID AND SOMEWHAT UNSETTLED CONDITIONS TO THE AREA MUCH OF NEXT WEEK...WITH A CHANCE OF RAINFALL EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...SCATTERED SHOWER ACTIVITY IS DISSIPATING AS EXPECTED AS IT MOVES INLAND OVER A COOLER AND MORE STABLE NOCTURNAL BOUNDARY LAYER. ADDITIONAL ISOLATED SHOWERS ARE STILL POSSIBLE OVERNIGHT...ALTHOUGH THE LAST TWO HRRR MODEL RUNS SHOW LESS AND LESS COVERAGE AS THE NIGHT PROGRESSES. TEMPERATURES AND DEWPOINTS ARE ON-TRACK AND NO SIGNIFICANT CHANGES ARE NEEDED WITH THIS UPDATE. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... MOIST ONSHORE FLOW WILL CONTINUE THROUGH THE NIGHT WITH 2.0+ INCH PRECIPITABLE WATER VALUES STREAMING IN. THE ATMOSPHERE WILL REMAIN CONVECTIVELY UNSTABLE FOR PARCELS ORIGINATING OFFSHORE WHERE SURFACE AIR TEMPERATURES WILL REMAIN IN THE LOWER 80S WITH MID 70S DEWPOINTS OVERNIGHT. WE WILL THEREFORE MAINTAIN SMALL POPS WITHIN 20 MILES OF THE BEACHES FOR ISOLATED SHOWERS BRUSHING BY. SOME OF THESE ARE ALREADY MOVING ONSHORE IN THE MYRTLE BEACH VICINITY AT THE TIME OF THIS WRITING. SKIES SHOULD AVERAGE MOSTLY CLEAR TO PARTLY CLOUDY. WITH A TROPICAL AIRMASS LOW TEMPERATURES SHOULD ONLY FALL INTO THE LOWER 70S INLAND AND MID 70S AT THE COAST. BEACHES WILL FALL TO THE UPPER 70S TO NEAR 80 DEGREES WITH ONSHORE BREEZES. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...OUR AIR MASS BEGINS TO MOISTEN UP SUNDAY THEN ESPECIALLY MONDAY AS A TROPICAL WAVE MOVES INLAND ACROSS FLORIDA...AND PREVAILING DEEP SW FLOW GUIDES THE TROPICAL AIR INTO THE EASTERN CAROLINAS. SURFACE PRESSURE FIELDS REMAIN WEAK IN THIS TIME FRAME AND MESOSCALE SURFACE FEATURES WILL DICTATE CONVECTIVE TRENDS...SUCH AS THE LAND BREEZE...SEA BREEZE FRONT AND OUTFLOW BOUNDARIES. A POTENTIAL FOR LOCALIZED FLOODING EXISTS SINCE STORM MOTION WILL BE QUITE LAZY IN PULSE TYPE THUNDERSTORMS WHOSE DOWNBURSTS WILL VERY LIKELY PERPETUATE ADDITIONAL STORMS. TEMPERATURES WILL ADHERE CLOSE TO CLIMATOLOGY FOR EARLY AUGUST BUT MINIMUM TEMPERATURES MAY RUN A FEW DEGREES ABOVE NORMAL DUE TO CLOUDS AND THE VERY TROPICAL AIR MASS ACROSS THE REGION. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...PERIOD WILL BE MARKED BY SUBTLE 5H TROUGHING IN VARYING STRENGTHS. TROUGH AXIS REMAINS WEST OF THE AREA...KEEPING DEEP MOIST SOUTHWEST FLOW IN PLACE THROUGH SATURDAY. WEAK FRONT STALLED NORTHWEST OF THE AREA TUE WILL DRIFT INTO THE AREA WED AS IT WEAKENS...BECOMING LITTLE MORE THAN A SURFACE TROUGH. SEVERAL FACTORS SUGGEST A CONVECTIVELY ACTIVE LONGER TERM PERIOD. LOW LEVEL CONVERGENCE ALONG THE SEA BREEZE...SURFACE TROUGH...AND OUTFLOW BOUNDARIES WILL BE ENHANCED BY DIVERGENCE ALOFT...AS WILL DIURNAL INSTABILITY. NOR WILL THERE BE A LACK OF DEEP MOISTURE...WITH FORECAST SOUNDINGS SHOWING PRECIPITABLE WATER VALUES ABOVE 2 INCHES FOR MUCH OF THE PERIOD. HARD TO PICK WHICH DAYS ARE MORE FAVORABLE POP WISE THOUGH WED AND FRI STAND OUT. WED WEAK SHORTWAVE MOVES NORTHEAST FROM THE GULF COAST AND FRI THE 5H TROUGH BECOMES A LITTLE MORE DEFINED...INCREASING DIVERGENCE. TEMPERATURES WILL REMAIN NEAR CLIMO THROUGH THE PERIOD. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 00Z...VFR EXPECTED THROUGH VALID PERIOD...WITH EXCEPTION OF POTENTIAL PATCHY/LIGHT FOG OVERNIGHT INTO SUNDAY. ISOLATED LIGHT SHOWERS OFFSHORE WILL SLOWLY PROGRESS ONTO THE MAINLAND AS SEEN BY CURRENT RADAR IMAGERY. AS A RESULT...HAVE KEPT IN A VCSH FOR THE COASTAL SITES FOR THE NEXT COUPLE OF HOURS...THOUGH ANTICIPATE ANY MVFR RESTRICTIONS TO BE A RESULT OF LOW STRATUS CLOUDS AND NOT VISIBILITY FROM ANY SHRA. OVERNIGHT...LIGHT SOUTHEAST WINDS WILL PREVAIL WITH FEW/SCT MID TO HIGH-LEVEL CLOUDS ACROSS THE AREA. CANNOT RULE OUT LIGHT PATCHY FOR FOR A FEW HOURS...ESPECIALLY AT THE INLAND SITES...OVERNIGHT INTO THE EARLY MORNING HOURS. AFTER DAYBREAK...ANY LINGERING FOG WILL QUICKLY DISSIPATE ALLOWING FOR VFR TO PREVAIL. WITH A VERY TROPICAL AIRMASS IN PLACE...ANTICIPATE CU AND TCU TO DEVELOP THROUGHOUT THE DAY...INCREASING THE POTENTIAL FOR AFTERNOON CONVECTION ALONG THE SEABREEZE. ATTM...HAVE INTRODUCED VCTS INTO CURRENT FCST. SOUTH WINDS WILL PREVAIL WITH SUSTAINED WINDS AOB 12 KTS. EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...WIND AND SEA OBSERVATIONS ARE SUPPORTED BY THE CURRENT FORECAST AND NO UPDATES ARE NEEDED. RADAR SHOWS SHOWER ACTIVITY BECOMING MORE ISOLATED IN NATURE CURRENTLY...AND THE LATEST COUPLE OF HRRR MODEL RUNS SHOW VERY FEW SHOWERS REMAINING AFTER MIDNIGHT. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... SOUTH-SOUTHEAST WINDS 10-15 KT WILL CONTINUE OVERNIGHT AS WEAK LOW PRESSURE PUSHES ONTO THE FLORIDA EAST COAST. THIS SAME FLOW HAS ENOUGH VERTICAL EXTENT TO PUSH SCATTERED SHOWERS NORTH-NORTHWESTWARD ACROSS THE COASTAL WATERS. LATEST HIGH-RESOLUTION MODELS SHOW THE BEST COVERAGE FOR THESE SCATTERED SHOWERS SHOULD BE THIS EVENING WITH A LITTLE LESS COVERAGE AFTER MIDNIGHT. SEAS SHOULD AVERAGE 2-3 FT WITH SPECTRAL WAVE PLOTS SHOWING PEAKS IN POWER AT AROUND 6 AND 8 SECOND PERIODS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...SINCE ERNESTO WILL TRACK ACROSS THE SOUTHERN CARIBBEAN...ISLANDS WILL BLOCK ANY CHANCE OF LONG PERIOD WAVES REACHING THE NC COAST SUNDAY AND MONDAY. SE WINDS AROUND 15 KT SUNDAY WILL BUILD SEAS TO 3-4 FEET PRIMARILY IN SE WAVES WITH WAVE INTERVALS AROUND 6-7 SECONDS SUNDAY. WINDS WILL TURN SOUTHERLY AND EASE A BIT MONDAY AS A WEAK TROPICAL WAVE MOVING ACROSS FLORIDA BREAKS INTO THE GULF OF MEXICO. SEAS MAY SUBSIDE A FOOT OR SO MONDAY...BUT RESIDUAL WAVE ENERGY FROM THE SSE FETCH COULD KEEP SEA HEIGHTS STEADY AND A 2-4 FOOT RANGE...HIGHEST OFFSHORE UN-CONSUMED BY BOTTOM FRICTION AND SHOALING. ALL MARINERS ARE ENCOURAGED TO GET A FIX ON RADAR TRENDS BEFORE HEADING OUT TO ASCERTAIN THE THREAT OF OCEAN STORMS...SINCE THE TROPICAL AIR MASS WILL SUPPORT ISOLATED TO SCATTERED STORMS JUST ABOUT ANY TIME OF DAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 PM SATURDAY...BERMUDA HIGH AND STALLED FRONT/PIEDMONT TROUGH WILL MAINTAIN THE TYPICAL SUMMERTIME CONDITIONS ACROSS THE WATERS. SOUTHWEST FLOW WILL GENERALLY RANGE BETWEEN 10 AND 15 KT AND SEAS RUNNING 2 TO 3 FT WITH ISOLATED 4 FT WELL AWAY FROM SHORE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...MJC LONG TERM...III AVIATION...SGL
AREA FORECAST DISCUSSION...UPDATED
NWS NEWPORT/MOREHEAD CITY NC
953 AM EDT FRI AUG 3 2012 .SYNOPSIS... WEAK UPPER LEVEL LOW PRESSURE WILL GRADUALLY LIFT OUT TODAY AS HIGH PRESSURE BUILDS WEST INTO THE AREA FROM OFFSHORE THROUGH THE WEEKEND. A COLD FRONT WILL APPROACH FROM THE NORTHWEST MONDAY AND STALL ACROSS THE PIEDMONT INTO THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TODAY/... AS OF 945 AM FRIDAY...MINOR ADJUSTMENTS WITH THE MORNING UPDATE MAINLY TO REMOVE POPS FOR WESTERN ZONES AS CONVECTION HAS REMAINED JUST WEST OF THE AREA...WITH HRRR AND MESOMODELS KEEPING PRECIP OUT UNTIL THIS AFTERNOON. MINOR TWEAKS TO TEMPS/DEWPOINTS WITH TEMPS REBOUNDING SLIGHTLY FASTER THAN FORECAST DUE TO LACK OF CLOUD COVER AND FULL INSOLATION...STILL EXPECT LOWS IN THE LOWER 90S INLAND TODAY. WEAK UPPER LEVEL LOW TO THE SOUTH WILL GRADUALLY LIFT OUT TO THE NORTH TODAY. 500 MB ANALYSIS INDICATES -10 C AT 00Z AND GIVEN THIS RATHER COLD AIR ALOFT AND SOME MODERATE SURFACE BASED INSTABILITY THIS AFTERNOON WITH CAPES IN THE 1000 TO 1500 J/KG RANGE AND LIFTED INDICES OF -4 TO -6 C...WILL FORECAST ISOLATED TSTMS ALONG INLAND AREAS ASSOCIATED WITH THE SEA BREEZE. MAX TEMPERATURES AREA-WIDE SHOULD BE IN THE UPPER 80S TO LOWER 90S. && .SHORT TERM /TONIGHT/... AS OF 315 AM FRIDAY...THE UPPER AIR PATTERN STARTS TO CHANGE BY LATER TONIGHT AS H5 RIDGE NEAR BERMUDA STARTS TO BUILD WEST WITH STEADY HEIGHT RISES INDICATED OVERNIGHT. ANY CONVECTION SHOULD SHIFT FROM THE LAND TO THE COASTAL AREAS AND OFFSHORE WATERS AND WILL HAVE A SLIGHT CHANCE OVERNIGHT. MINIMUM TEMPERATURES TONIGHT GENERALLY FROM 73 TO 78 DEGREES ACROSS THE REGION. && .LONG TERM /SATURDAY THROUGH THURSDAY/... AS OF 245 AM FRI...CONTINUED WITH LITTLE CHANGES TO THE FORECAST OR FORECAST REASONING THROUGH THE LONG TERM. HIGH PRESSURE ALOFT WILL CONTINUE TO EXTEND INTO THE AREA FROM THE WESTERN ATLANTIC THROUGH THE WEEKEND. THE BERMUDA HIGH ALSO STRENGTHENS OFFSHORE ALLOWING MOIST SOUTHERLY FLOW TO CONTINUE THROUGH THE EXTENDED. EXPECT ISOLATED TO SCATTERED DIURNAL CONVECTION INLAND AND ALONG THE SEA BREEZE BOUNDARY THROUGH THE WEEKEND. LOW LEVEL THICKNESSES WILL PERSIST AT 1415-1420 METERS...YIELDING TEMPS NEAR CLIMATOLOGY WITH HIGHS IN THE LOW/MID 90S INLAND TO 80S ALONG THE COAST. A FRONTAL BOUNDARY IS PROGGED TO APPROACH THE AREA FROM THE NORTHWEST MON WITH MOIST SOUTHWESTERLY FLOW AND INCREASING LOW LEVEL SHEAR AHEAD OF A ROBUST MID LEVEL SHORTWAVE. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE MON AFTERNOON/EVENING WITH PWATS AGAIN BUILDING ABOVE 2 INCHES. 12Z OPERATIONAL ECMWF AND GFS INDICATE THE FRONT WILL STALL JUST WEST OF THE REGION ACROSS THE CENTRAL PIEDMONT AND MID ATLANTIC STATES LATE MON THROUGH THURS WHILE AN UPPER TROUGH BECOME RE-ESTABLISHED ACROSS THE EASTERN CONUS. 00Z/12Z ECMWF SUGGEST A WEAK SURFACE LOW WILL FORM ALONG THE FRONT TUES NIGHT AND PUSH NE OFF THE MID ATLANTIC COAST WED INTO WED NIGHT. WILL MAINTAIN CHANCE POPS TUES THROUGH THURS WITH THE UPPER TROUGH AND STALLED SURFACE FRONT CONTINUING ACROSS THE REGION WHILE WEAK SHORTWAVES MOVE THROUGH THE FLOW ALOFT. LOW LEVEL THICKNESSES WILL REMAIN AROUND 1415 METERS MON THROUGH THURS HOWEVER GREATER CLOUD COVER AND PRECIP MAY MODERATE TEMPS FROM REACHING ABOVE THE 90 DEGREE MARK EACH DAY. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... SHORT TERM /THROUGH 06Z SATURDAY/... AS OF 650 AM FRIDAY...FOG AND STRATUS HAS FAILED TO MATERIALIZE THIS MORNING WITH THE EXCEPTION OF SOME 4 MILE VSBYS AT KOAJ. THIS FOG...AND ANY FOG THAT DEVELOPS AT THE OTHER TAF SITES...SHOULD DISSIPATE QUICKLY WITH VFR CONDITIONS EXPECTED THROUGH TODAY AND INTO TONIGHT. LONG TERM /SATURDAY THROUGH TUESDAY/ AS OF 245 AM FRI...PREDOMINANT VFR AVIATION CONDITIONS EXPECTED THROUGH THE EXTENDED. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN DIURNAL CONVECTION EACH DAY. SOUTHWESTERLY SURFACE FLOW WILL PERSIST INTO EARLY NEXT WEEK WITH HIGH PRESSURE ANCHORED OFFSHORE. A FRONTAL BOUNDARY WILL APPROACH FROM THE NORTHWEST MON NIGHT INTO TUES WITH SHOWERS AND THUNDERSTORMS EXPECTED AHEAD OF AND ALONG THE BOUNDARY. && .MARINE... SHORT TERM /THROUGH TONIGHT/... AS OF 950 AM FRIDAY...LATEST SURFACE AND BUOY OBSERVATIONS INDICATE LIGHT SE BREEZE 4-8 KNOTS WITH MEDIUM PERIOD SWELLS 2-3 FEET AT 8-9 SECONDS. A LIGHT S/SW WINDS AT 10 KNOTS OR LESS WITH A GENTLE SOUTHEAST SWELL COMPONENT WILL MAKE FOR ANOTHER 24 HOURS OF BENIGN MARINE CONDITIONS TODAY AND TONIGHT. WAVEWATCH AND LOCAL SWAN IN PRETTY GOOD AGREEMENT SHOWING 2 TO 3 FOOT SEAS TODAY AND TONIGHT AND WINDS WILL GENERALLY NOT EXCEED ABOUT 10 OR 12 KNOTS FROM THE SOUTH TO SOUTHWEST THROUGH EARLY SATURDAY MORNING. LONG TERM /SATURDAY THROUGH TUESDAY/ AS OF 245 AM FRI...GOOD BOATING CONDITIONS EXPECTED SAT AND SUN WITH THE BERMUDA HIGH STRENGTHENING OVER THE WESTERN ATLANTIC BRINGING SLY WINDS ACROSS THE WATERS. SPEEDS WILL RANGE GENERALLY 10-15 KNOTS WITH SEAS 2 TO 3 FT. ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THROUGH THE WEEKEND AS WELL. GRADIENT BEGINS TO TIGHTEN LATE SUN AND MON AS FRONTAL SYSTEM APPROACHES FROM THE NW AND EXPECT WINDS TO INCREASE TO AROUND 15-20 KT...MAINLY ACROSS THE NORTHERN AND CENTRAL WATERS. SWAN/WAVEWATCH HAVE BACKED OFF SLIGHTLY WITH SEAS EARLY NEXT WEEK...NOW ONLY BUILDING ABOUT A FOOT OR SO...UP TO 4 FT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...CTC NEAR TERM...CTC/DAG SHORT TERM...CTC LONG TERM...SK/DAG AVIATION...CTC/SK/DAG MARINE...CTC/SK/DAG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
221 PM CDT FRI AUG 3 2012 .SHORT TERM (TONIGHT-MONDAY)...MAIN CONCERN WILL BE SEVERE POTENTIAL. 12Z MODELS IN DECENT AGREEMENT AND WILL USE A BLEND FOR DETAILS. SITUATION APPEARS TO BE UNFOLDING AS EXPECTED. SURFACE BOUNDARY/COLD FRONT ACROSS CENTRAL NORTH DAKOTA WILL CONTINUE TO PROPAGATE EASTWARD INTO THE EVENING HOURS. AS FORCING (SEEN BY SHOWERS AND THUNDERSTORMS BEHIND THIS FEATURE) MOVES INTO THE AREA OF HIGHER INSTABILITY (WEAKER CIN) EXPECT MORE SURFACE BASED AND THUS STRONGER STORMS...LIKELY BY 20Z-21Z. EXPECTING A STRONG LINE OF STORMS TO MOVE THROUGH THE REGION FROM WEST TO EAST...MUCH LIKE THE HRRR HAS BEEN SUGGESTING. THE MAIN QUESTION AT THIS POINT IS WHETHER OR NOT VERY STRONG DEEP LAYER (50+ KNOTS) ENTERING THE WESTERN FA AFTER 00Z WILL INTERACT WITH THE LINE OF STORMS. THE STRONGEST DEEP LAYER SHEAR MAY LAG THE STORMS...BUT INCREASING SHEAR SHOULD HELP AID ORGANIZED ACTIVITY. SEE SWODY1/SWOMCD 1691/WATCH 553 FOR MORE DETAILS. MADE SOME MINOR CHANGES TO POP/WX GRIDS BASED ON EXPECTED TIMING. SATURDAY...UPPER LOW WILL SLOWLY PROPAGATE THROUGH THE REGION. COLD AIR ADVECTION AND WINDY CONDITIONS EXPECTED BY THE AFTERNOON HOURS...ALONG WITH SHOWERS AND POSSIBLY THUNDER. SUNDAY-MONDAY...NORTHWEST FLOW ALOFT WITH WARMING AIRMASS WILL BE THE GENERAL RULE. A WEAK FROPA IS EXPECTED ON MONDAY...BUT DRY AIRMASS WILL REMAIN IN PLACE AND NO PRECIP EXPECTED. .LONG TERM (MONDAY NIGHT-FRIDAY)...MEDIUM RANGE MODELS SHARE SAME BASIC LARGE-SCALE SYNOPTIC PATTERN NEXT WEEK...BUT DIFFER QUITE A BIT IN DETAIL. WITH RIDGE CENTERED OVER THE FOUR CORNERS AND A HUDSON BAY TROUGH...NORTHWEST FLOW ALOFT WILL PREVAIL ACROSS THE NORTHERN PLAINS. BOTH GFS/ECMWF PAINT PERIODS OF LIGHT QPF TUESDAY NIGHT THROUGH THE END OF THE WEEK WITH WEAK EMBEDDED SHORT- WAVES...SO WILL MAINTAIN ALL BLEND 20 TO 30 POPS. NO REAL CHANGE IN AIR MASS...SO TEMPERATURES WILL RANGE FROM THE 80S DURING THE DAY TO THE 60S AT NIGHT. && .AVIATION...SHOWERS AND THUNDERSTORMS ACROSS CENTRAL ND WILL MOVE EAST- NORTHEASTWARD LATE THIS AFTERNOON AND EVENING...IMPACTING ALL TAF SITES. SOME STORMS MAY BE SEVERE WITH DAMAGING WIND AND LARGE HAIL. CEILINGS AND VISIBILITY MAY ALSO DROP INTO THE MVFR/IFR RANGE WITH STRONGER STORMS. GUSTY SOUTH-SOUTHEAST WIND WILL SHIFT TO THE WEST-NORTHWEST OVERNIGHT AFTER COLD FRONTAL PASSAGE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG/ROGERS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1136 PM EDT SAT AUG 4 2012 .SYNOPSIS... A STRONG COLD FRONT FROM THE MISSISSIPPI VALLEY WILL SWEEP ACROSS THE AREA ON SUNDAY. HIGH PRESSURE WILL MOVE ACROSS THE AREA ON MONDAY. THE NEXT WEEK COLD FRONT WILL CROSS THE AREA ON WEDNESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... LATEST UPDATE TO CLEAR LUCAS WOOD AND HANCOCK FROM THE WATCH. WE ARE WATCHING CONVECTION OVER ST. LOUIS. LATEST HRRR MODELS SHOWS THIS ACTIVITY MOVING NORTHEAST INTO THE FORECAST AREA BY 14Z IN THE MORNING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/... THE INITIAL BATCH OF SHOWERS/STORMS WILL TRY TO MOVE EAST OF THE AREA SUNDAY MORNING BUT ADDITIONAL LINES OF SHOWERS AND STORMS WILL DEVELOP...THE LAST BATCH BEING WITH THE COLD FRONT. DRIER AIR/SUBSIDENCE WILL INCREASE FROM WEST TO EAST DURING THE AFTERNOON AS THE FRONT CROSSES THE AREA AND TOLEDO WILL LIKELY HAVE A DECENT AFTERNOON WITH A BREEZY WEST WIND AND FALLING DEW POINTS. IT WILL TAKE UNTIL SUNDAY LATE AFTERNOON/EARLY EVENING TO GET MOST OF THE SHOWERS EAST OF THE FORECAST AREA. A FEW LAKE EFFECT/ENHANCED SHOWERS MIGHT LINGER ACROSS THE SNOWBELT COUNTIES OF EXTREME NE OH/NW PA THROUGH MONDAY MORNING AS THE THERMAL TROUGH ALOFT PASSES OVER THE AREA. 850 MB TEMPERATURES ARE PROGGED TO DROP TO 10C. HIGH PRESSURE WILL BUILD IN FROM THE WEST ON MONDAY AND IT WILL BE MUCH COOLER WITH HIGHS IN THE 70S TO LOWER 80S AND LOW DEW POINTS. THE RETURN SOUTH TO SOUTHWEST FLOW WILL DEVELOP ON TUESDAY AND HIGH TEMPERATURES WILL RECOVER A COUPLE OF CATEGORIES AND IT WILL REACH THE MID TO UPPER 80S IN TOLEDO. THE NEXT COLD FRONT WILL BEGIN TO DROP SOUTH ACROSS THE GREAT LAKES. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE OVERALL PATTERN FOR THE EXTENDED WILL BE A TROUGH OVER THE CENTRAL GREAT LAKES REGION. A FEW PIECES OF ENERGY ASSOCIATED WITH WEAK COLD FRONTS WILL BREAK-OFF FROM TIME-TO-TIME AND BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA POSSIBLY WEDNESDAY AND AGAIN ON FRIDAY. FOR TEMPERATURES...WEDNESDAY WILL PROBABLY BE THE WARMEST DAY OF THE EXTENDED PERIOD WITH HIGHS IN THE LOWER TO MID 80S. HIGHS BY FRIDAY INTO SATURDAY SHOULD BE A BIT COOLER WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... MOISTURE VALUES WILL CONTINUE TO INCREASE THIS AFTERNOON AS THE SOUTHERLY FLOW INCREASES IN ADVANCE OF AN APPROACHING COLD FRONT SLATED TO SWEEP ACROSS OHIO SUNDAY AFTERNOON. DUE TO THE INCREASED MOISTURE ESPECIALLY KMFD AND SOUTH THERE MAY BE A FEW SHOWERS/THUNDERSTORMS THAT COULD CLIP THAT AREA. FOR TONIGHT LOOK FOR A BETTER CHANCE OF THUNDERSTORMS...PROBABLY AFTER 06Z. THESE THUNDERSTORMS WILL LIKELY DEVELOP OVER MICHIGAN SOUTHWARD INTO ILLINOIS AND COULD BRING SOME GUSTY WINDS. .OUTLOOK...NON VFR SUNDAY IN SHOWERS/THUNDERSTORMS. && .MARINE... SOUTHERLY WINDS WILL INCREASE THIS AFTERNOON AND BECOME A BIT GUSTY DURING THE OVERNIGHT HOURS. WITH THE SOUTHWEST WINDS GETTING STRONGER LOOK FOR THE WAVES TO BUILD ACROSS THE OPEN WATERS OF LAKE ERIE. AN ACTIVE COLD FRONT MOVES INTO THE LAKE ON SUNDAY RESULTING IN STRONGER WINDS AND WAVES DURING THE DAY ON SUNDAY. SOUTHWEST WINDS WILL BECOME WEST THEN NORTHWEST AFTER FRONTAL PASSAGE. THE MOVEMENT OF THIS FRONTAL SYSTEM WILL RESULT IN A SMALL CRAFT ADVISORY BEING POSTED ON SUNDAY...BEGINNING AT 14Z. HIGH PRESSURE WILL BUILD SOUTHEAST ON MONDAY WITH NORTHERLY WINDS SHIFTING TO WEST AND SOUTHWEST BY TUESDAY. THE NEXT WEAK COLD FRONT MAY ARRIVE ON WEDNESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 AM SUNDAY TO 4 AM EDT MONDAY FOR LEZ142>149. && $$ SYNOPSIS...KOSARIK NEAR TERM...LOMBARDY SHORT TERM...KOSARIK LONG TERM...BC AVIATION...BC MARINE...BC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
723 PM EDT SAT AUG 4 2012 .SYNOPSIS... MUGGY AUGUST AIR THROUGH WEEKEND. WITH A LOCAL DOWNPOUR POSSIBLE. MORE WIDESPREAD AND ORGANIZED CONVECTION LIKELY SUNDAY...WELL AHEAD OF COLD FRONT. DRIER AIR TRIES TO CREEP SOUTH MONDAY. && .NEAR TERM /THROUGH SUNDAY/... 630 PM UPDATE. OTHER THAN EASTERN KENTUCKY AND PARTS OF SOUTHEASTERN OHIO...CONVECTION HAS DISSIPATED FOR THE MOST PART. WILL UPDATE POPS OVERNIGHT TO LOWER TO SLIGHT CHANCE EAST OF THE OHIO RIVER AND KEEP MOSTLY CHANCE POPS WEST OF THE OHIO RIVER...WHERE CONVECTION SEEMS TO REFORM AND TREK NORTH FROM EASTERN KENTUCKY IN WEAK DIFFLUENT FLOW ALOFT. WILL MAINTAIN SLIGHT CHANCE ALL NIGHT ENTIRE AREA GIVEN THE SLIGHT ELEVATED INSTABILITY AND DEEP MOISTURE SHOWN BY THE MODELS OVERNIGHT. PREVIOUS DISCUSSION... CONVECTION CURRENTLY DEVELOPING IN ASSOCIATION WITH WEAK VORT MAX SHOWING UP ON RAP MOVING INTO CWA FROM THE WEST. DOWNPOURS WILL BE POSSIBLE WITH THESE STORMS...AND ISOLATED FLASH FLOODING MAY OCCUR. NOT EXPECTING FLASH FLOOD THREAT TO BE WIDESPREAD ENOUGH TO WARRANT A SHORT FLASH FLOOD WATCH THOUGH THIS EVENING. TOMORROW IS ANOTHER STORY...MOISTURE CONTINUES TO INCREASE OVERNIGHT...WITH PWAT VALUES CLIMBING TO OVER 2.25 INCHES BY 18Z SUNDAY ON THE NAM AND GFS. EXPECT WIDESPREAD PRECIPITATION...WITH VERY HEAVY RAINFALL SUNDAY AFTERNOON INTO SUNDAY NIGHT...AND OPTED TO ISSUE A FLASH FLOOD WATCH FOR LINE ROUGHLY HTS TO CKB AND SOUTH. ONE THING TO WATCH WILL BE STORM SPEEDS...WITH 20-30KTS MID LEVEL FLOW...STORMS WILL BE PROGRESSIVE...BUT WITH FLASH FLOOD GUIDANCE BETWEEN 1.5 AND 2 INCHES ACROSS A LOT OF THE WATCH AREA...EVEN STORMS THAT ARE MOVING COULD EASILY REACH THIS THRESHOLD. PLUS...IF ANY TRAINING CELLS OCCUR THREAT WILL INCREASE GREATLY. AS FOR SEVERE THREAT...MODELS HAVE BEEN BACKING OFF ON INSTABILITY A BIT. THINK THIS IS A GOOD TREND...DUE TO MORE CLOUDS LEADING TO LESS HEATING. STILL...1500-2000 J/KG CAPE SHOULD BE ENOUGH TO TAP INTO GOOD MID-LEVEL FLOW AND PRODUCE STRONG TO SEVERE WIND GUSTS IN THE TALLER STORMS. BLENDED IN MET GUIDANCE FOR TEMPS OVERNIGHT...AS IT HAS BEEN PERFORMING QUITE WELL LATELY...WHICH RESULTED IN MINIMAL CHANGES. WITH MORE CLOUDS AROUND...BLENDED IN THE MAV FOR HIGHS TOMORROW LIKING ITS DEPICTION OF COOLER TEMPS IN SE OHIO WHERE PRECIP WILL REACH FIRST. THIS RESULTED OVERALL IN A BIT COOLER DAY THAN PREVIOUS FORECAST. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... WE ARE HOPING THE PREFRONTAL CONVECTION DOES NOT ORIENT MORE EAST TO WEST...BUT THE FLASH FLOOD WATCH WAS POSTED EARLY...FOR THAT POSSIBILITY. AS WE HEAD INTO SUNDAY EVENING...OUR SOUTHERN COUNTIES SEEM TO BE MORE VULNERABLE TO SOME TRAINING...DESPITE THE 25 TO 30 KNOT CELL MOVEMENT THAT WE ARE EXPECTED. WILL BASE FORECAST ON SURFACE FRONT FROM NEAR EKN TO CRW TO SOUTH OF HTS AT 12Z MONDAY. SO HAD TO LEAVE SOME CHANCE POPS ALONG THAT FEATURE. PICTURING LOW CLOUDS ALONG THAT FRONT TOO. PROBABLY MOSTLY JUST LINGERING RAIN SHOWERS RATHER THAN THUNDER. PROBLEM THEN BECOMES...HOW LONG TO LINGER SOME 20/30 POPS IN OUR EXTREME SOUTH INTO TUESDAY. WE ARE TYPICALLY LEARY OF THE DRIER AIR IN THE LOW LEVELS MAKING IT THROUGH THE SOUTHERN MOUNTAINS. SO EVEN THOUGH THE MID LEVELS SHOULD DRY OUT...WILL NOW HOLD ONTO SOME 20/30 POPS IN SW VIRGINIA TO NEAR BECKLEY FOR TUESDAY. THERE COULD BE WIDESPREAD FOG MONDAY NIGHT FROM EKN TO CRW INTO THE COAL FIELDS. YET...BEING THE THIRD NIGHT INTO THE FUTURE...WILL HOLD OFF INCLUDING THOSE SPECIFICS FOR NOW. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... 12Z GFS AND 12Z ECMWF SOLUTIONS CONTINUE TO AGREE THAT THE MID LEVEL RIDGE...BAKING THE PLAINS THIS SUMMER...WILL SLIDE BACK WEST INTO THE GREAT BASIN...WITH A STRONG TROF SWINGING THROUGH OUR VICINITY ON DAY 7...WITH THE SURFACE FRONT LIKELY AHEAD OF IT...ON DAY 6/FRIDAY. PROBLEM FOR WEDNESDAY AND THURSDAY IS THE DEEP MOISTURE LINGERING TO OUR SOUTHEAST. WILL TRY TO HOLD WEDNESDAY DRY MAINLY FOR COUNTIES NORTH OF A HTS-CRW-EKN LINE...WITH SOME 20/30 POPS ALONG OUR SOUTHEASTERN COUNTIES WEDNESDAY. WENT ALONG WITH HPC MEDIUM RANGE CHANCE POPS FOR THURSDAY AND FRIDAY...WITH A COOL DOWN FOR SATURDAY. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... 00Z SUNDAY THRU 00Z MONDAY... MOST CONVECTION ENDING THIS EVENING WITH LOSS OF HEATING..ALTHOUGH THERE MAY BE A POP UP SHOWER OR STORM ANYTIME OVERNIGHT... ESPECIALLY WEST OF THE OHIO RIVER. WILL NOT INCLUDE THUNDER IN TAFS AFTER 02Z FOR THE OVERNIGHT HOURS. OTHERWISE...GENERALLY VFR CEILINGS 5000-8000 FEET DEVELOPING OVERNIGHT. MINIMAL FOG IF ANY DUE TO SOUTHERLY BREEZES BEING MAINTAINED. AFTER 12Z...COLD FRONT APPROACHES FROM THE WEST WITH INCREASING SHOWERS AND THUNDERSTORMS FROM WEST TO EAST ON SUNDAY. SOME STORMS MAY BE SEVERE. OUTSIDE OF STORMS GENERALLY VFR CEILINGS 3500-4500 FEET BEFORE LOWERING NEAR END OF PERIOD. EXPECT GUSTY SOUTHWEST WINDS AHEAD OF THE FRONT ON SUNDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND INTENSITY OF SHOWERS AND THUNDERSTORMS SUNDAY WILL DEPEND OF AMOUNT OF CLOUDS AND HEATING. 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 SUN 08/05/12 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 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 M 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 00Z MONDAY... BRIEF IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS INTO SUNDAY NIGHT. IFR IN LOW STRATUS POSSIBLE NEAR SURFACE FRONT MONDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR WVZ005-006-013>020-024>040-046-047. OH...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR OHZ087. KY...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR VAZ003-004. && $$ SYNOPSIS...KTB/MZ NEAR TERM...JMV/MZ SHORT TERM...KTB/ARJ LONG TERM...KTB AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
634 PM EDT SAT AUG 4 2012 .SYNOPSIS... MUGGY AUGUST AIR THROUGH WEEKEND. WITH A LOCAL DOWNPOUR POSSIBLE. MORE WIDESPREAD AND ORGANIZED CONVECTION LIKELY SUNDAY...WELL AHEAD OF COLD FRONT. DRIER AIR TRIES TO CREEP SOUTH MONDAY. && .NEAR TERM /THROUGH SUNDAY/... 630 PM UPDATE. OTHER THAN EASTERN KENTUCKY AND PARTS OF SOUTHEASTERN OHIO...CONVECTION HAS DISSIPATED FOR THE MOST PART. WILL UPDATE POPS OVERNIGHT TO LOWER TO SLIGHT CHANCE EAST OF THE OHIO RIVER AND KEEP MOSTLY CHANCE POPS WEST OF THE OHIO RIVER...WHERE CONVECTION SEEMS TO REFORM AND TREK NORTH FROM EASTERN KENTUCKY IN WEAK DIFFLUENT FLOW ALOFT. WILL MAINTAIN SLIGHT CHANCE ALL NIGHT ENTIRE AREA GIVEN THE SLIGHT ELEVATED INSTABILITY AND DEEP MOISTURE SHOWN BY THE MODELS OVERNIGHT. PREVIOUS DISCUSSION... CONVECTION CURRENTLY DEVELOPING IN ASSOCIATION WITH WEAK VORT MAX SHOWING UP ON RAP MOVING INTO CWA FROM THE WEST. DOWNPOURS WILL BE POSSIBLE WITH THESE STORMS...AND ISOLATED FLASH FLOODING MAY OCCUR. NOT EXPECTING FLASH FLOOD THREAT TO BE WIDESPREAD ENOUGH TO WARRANT A SHORT FLASH FLOOD WATCH THOUGH THIS EVENING. TOMORROW IS ANOTHER STORY...MOISTURE CONTINUES TO INCREASE OVERNIGHT...WITH PWAT VALUES CLIMBING TO OVER 2.25 INCHES BY 18Z SUNDAY ON THE NAM AND GFS. EXPECT WIDESPREAD PRECIPITATION...WITH VERY HEAVY RAINFALL SUNDAY AFTERNOON INTO SUNDAY NIGHT...AND OPTED TO ISSUE A FLASH FLOOD WATCH FOR LINE ROUGHLY HTS TO CKB AND SOUTH. ONE THING TO WATCH WILL BE STORM SPEEDS...WITH 20-30KTS MID LEVEL FLOW...STORMS WILL BE PROGRESSIVE...BUT WITH FLASH FLOOD GUIDANCE BETWEEN 1.5 AND 2 INCHES ACROSS A LOT OF THE WATCH AREA...EVEN STORMS THAT ARE MOVING COULD EASILY REACH THIS THRESHOLD. PLUS...IF ANY TRAINING CELLS OCCUR THREAT WILL INCREASE GREATLY. AS FOR SEVERE THREAT...MODELS HAVE BEEN BACKING OFF ON INSTABILITY A BIT. THINK THIS IS A GOOD TREND...DUE TO MORE CLOUDS LEADING TO LESS HEATING. STILL...1500-2000 J/KG CAPE SHOULD BE ENOUGH TO TAP INTO GOOD MID-LEVEL FLOW AND PRODUCE STRONG TO SEVERE WIND GUSTS IN THE TALLER STORMS. BLENDED IN MET GUIDANCE FOR TEMPS OVERNIGHT...AS IT HAS BEEN PERFORMING QUITE WELL LATELY...WHICH RESULTED IN MINIMAL CHANGES. WITH MORE CLOUDS AROUND...BLENDED IN THE MAV FOR HIGHS TOMORROW LIKING ITS DEPICTION OF COOLER TEMPS IN SE OHIO WHERE PRECIP WILL REACH FIRST. THIS RESULTED OVERALL IN A BIT COOLER DAY THAN PREVIOUS FORECAST. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... WE ARE HOPING THE PREFRONTAL CONVECTION DOES NOT ORIENT MORE EAST TO WEST...BUT THE FLASH FLOOD WATCH WAS POSTED EARLY...FOR THAT POSSIBILITY. AS WE HEAD INTO SUNDAY EVENING...OUR SOUTHERN COUNTIES SEEM TO BE MORE VULNERABLE TO SOME TRAINING...DESPITE THE 25 TO 30 KNOT CELL MOVEMENT THAT WE ARE EXPECTED. WILL BASE FORECAST ON SURFACE FRONT FROM NEAR EKN TO CRW TO SOUTH OF HTS AT 12Z MONDAY. SO HAD TO LEAVE SOME CHANCE POPS ALONG THAT FEATURE. PICTURING LOW CLOUDS ALONG THAT FRONT TOO. PROBABLY MOSTLY JUST LINGERING RAIN SHOWERS RATHER THAN THUNDER. PROBLEM THEN BECOMES...HOW LONG TO LINGER SOME 20/30 POPS IN OUR EXTREME SOUTH INTO TUESDAY. WE ARE TYPICALLY LEARY OF THE DRIER AIR IN THE LOW LEVELS MAKING IT THROUGH THE SOUTHERN MOUNTAINS. SO EVEN THOUGH THE MID LEVELS SHOULD DRY OUT...WILL NOW HOLD ONTO SOME 20/30 POPS IN SW VIRGINIA TO NEAR BECKLEY FOR TUESDAY. THERE COULD BE WIDESPREAD FOG MONDAY NIGHT FROM EKN TO CRW INTO THE COAL FIELDS. YET...BEING THE THIRD NIGHT INTO THE FUTURE...WILL HOLD OFF INCLUDING THOSE SPECIFICS FOR NOW. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... 12Z GFS AND 12Z ECMWF SOLUTIONS CONTINUE TO AGREE THAT THE MID LEVEL RIDGE...BAKING THE PLAINS THIS SUMMER...WILL SLIDE BACK WEST INTO THE GREAT BASIN...WITH A STRONG TROF SWINGING THROUGH OUR VICINITY ON DAY 7...WITH THE SURFACE FRONT LIKELY AHEAD OF IT...ON DAY 6/FRIDAY. PROBLEM FOR WEDNESDAY AND THURSDAY IS THE DEEP MOISTURE LINGERING TO OUR SOUTHEAST. WILL TRY TO HOLD WEDNESDAY DRY MAINLY FOR COUNTIES NORTH OF A HTS-CRW-EKN LINE...WITH SOME 20/30 POPS ALONG OUR SOUTHEASTERN COUNTIES WEDNESDAY. WENT ALONG WITH HPC MEDIUM RANGE CHANCE POPS FOR THURSDAY AND FRIDAY...WITH A COOL DOWN FOR SATURDAY. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... CONVECTION JUST BEGINNING TO FORM ACROSS THE EASTERN MOUNTAINS...AND ALSO IN EASTERN KY. EXPECT ADDITIONAL DEVELOPMENT THROUGH THE AFTERNOON...WITH SCATTERED SHOWERS AND THUNDERSTORMS LINGERING INTO THE EVENING. KEPT EVERYTHING VFR FOR TODAY...HOWEVER BRIEF MVFR IS POSSIBLE IN THE STRONGER CELLS. WITH MORE CLOUDS AND SOME WIND REMAINING OVERNIGHT...DO NOT EXPECT DENSE FOG TO FORM. WILL INCLUDED MVFR FOG TONIGHT IN MOST SHELTERED MOUNTAIN VALLEYS LIKE KEKN. TOWARDS THE END OF THE TAF PERIOD...EXPECT SHOWERS AND THUNDERSTORMS...WITH HEAVY RAIN POSSIBLE...TO BE ON THE INCREASE FROM WEST TO EAST AS COLD FRONT APPROACHES. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS: TIMING OF SHOWERS AND THUNDERSTORMS TODAY MAY VARY...WITH AMENDMENTS POSSIBLE. ADDITIONAL POCKETS OF FOG MAY FORM OVERNIGHT IF CLOUD BREAKS DEVELOP. 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 20 21 22 23 00 01 02 03 04 05 06 07 EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03 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 M M 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 00Z MONDAY... BRIEF IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS INTO SUNDAY NIGHT. IFR IN LOW STRATUS POSSIBLE NEAR SURFACE FRONT MONDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR WVZ005-006-013>020-024>040-046-047. OH...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR OHZ087. KY...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR VAZ003-004. && $$ SYNOPSIS...KTB/MZ NEAR TERM...JMV/MZ SHORT TERM...KTB/ARJ LONG TERM...KTB AVIATION...MZ
AREA FORECAST DISCUSSION
NWS NORMAN OK
322 PM CDT FRI AUG 3 2012 .DISCUSSION... ONGOING CRITICAL FIRE WEATHER CONDITIONS AND RECORD BREAKING HEAT ARE THE MAIN CONCERNS. HEAT ADVISORY IS IN GREAT SHAPE AND WILL NOT ALTER. THROUGH TONIGHT...WINDS WILL STAY UP IN THE 10 TO 15 MPH OVER MUCH OF THE AREA...THOUGH THE STRONGEST GUSTS SHOULD DIMINISH BETWEEN 6 AND 9 PM CDT. KEPT 20 PERCENT FOR SHOWERS AND STORMS OVER NORTHERN OKLAHOMA...MAINLY NORTH OF AN ARNETT TO STILLWATER LINE WHERE CAP IS WEAKEST. LATEST HRRR INDICATED NEW DEVELOPMENT THIS EVENING IN FAR NORTHWEST OKLAHOMA. GUSTY WINDS IS THE MAIN HAZARD WITH ANY STORM DUE TO HIGH CLOUD BASES. SATURDAY WILL BE ANOTHER VERY HOT DAY...THOUGH MAY BE SLIGHTLY COOLER DUE TO SLIGHTLY COOLER LOW LEVEL TEMPERATURES. A WEAK FRONT WILL PUSH INTO NORTHERN OKLAHOMA DURING THE AFTERNOON AND EVENING HOURS WHICH MAY ALLOW FOR ISOLATED STORM DEVELOPMENT...SO KEPT 20 PERCENT CHANCES IN THESE AREAS. SUNDAY THROUGH NEXT FRIDAY...DRY AND HOT CONDITIONS WILL LIKELY CONTINUE. TEMPERATURES WILL BE COOLER DURING THIS TIME FRAME...ESPECIALLY ON SUNDAY AS SOME LOCATIONS MAY NOT REACH 100 DEGREES. CANNOT COMPLETELY RULE OUT A FEW STORMS SUNDAY AND MONDAY...BUT KEPT A DRY FORECAST DUE TO LOW CONFIDENCE OF OCCURRENCE. MBS && .FIRE WEATHER... CURRENT RED FLAG WARNING IS IN GOOD SHAPE AND CONTINUES UNTIL 10 PM CDT. GUSTY SOUTH TO SOUTHWEST WINDS WILL DIMINISH SLIGHTLY BETWEEN 6 AND 9 PM CDT AND SHIFT MAINLY TO THE SOUTH. LOCATIONS NORTH OF A WEAK OUTFLOW BOUNDARY FROM PUTNAM TO CHANDLER HAVE A LOWER CHANCE FOR FIRE IGNITIONS. UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG WARNING FOR THE SAME AREAS ON SATURDAY DUE TO VERY SIMILAR FORECAST CONDITIONS. WINDS MAY BE A NUDGE STRONGER ON SATURDAY COMPARED TO TODAY. LIGHTER WINDS AND COOLER TEMPERATURES WILL ALLOW FOR SLIGHTLY LOWER WILDFIRE POTENTIAL SUNDAY INTO NEXT WEEK. && .CLIMATE... OKLAHOMA CITY HAS ALREADY REACHED 112 DEGREES TODAY SETTING A NEW DAILY RECORD. THE ALL TIME RECORD OF 113 DEGREES MAY BE TIED OR EXCEEDED IN THE NEXT FEW HOURS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 112 83 109 74 / 20 0 10 10 HOBART OK 111 79 109 75 / 10 0 0 10 WICHITA FALLS TX 111 80 110 77 / 0 0 0 0 GAGE OK 103 74 100 66 / 30 20 20 30 PONCA CITY OK 107 78 110 69 / 40 10 20 30 DURANT OK 106 78 107 77 / 0 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR OKZ008-012-013- 016>047-050-051. RED FLAG WARNING FROM 10 AM TO 10 PM CDT SATURDAY FOR OKZ008-012- 013-016>047-050-051. HEAT ADVISORY UNTIL 11 PM CDT SATURDAY FOR OKZ004>048-050>052. TX...RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR TXZ083>090. RED FLAG WARNING FROM 10 AM TO 10 PM CDT SATURDAY FOR TXZ083>090. HEAT ADVISORY UNTIL 11 PM CDT SATURDAY FOR TXZ083>090. && $$ 84/17
AREA FORECAST DISCUSSION
NWS TULSA OK
1151 PM CDT THU AUG 2 2012 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. FOR THE 6Z TAFS... SHOWERS AND THUNDERSTORMS ARE CURRENTLY TRACKING SOUTHEASTWARD ACROSS A PORTION OF FAR NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS. HAVE VCTS IN KXNA AND KFYV TAFS UNTIL 9Z FOR THIS ACTIVITY. OTHERWISE... VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH THE ENTIRE 24 HOUR FORECAST PERIOD. && .PREV DISCUSSION... /ISSUED 931 PM CDT THU AUG 2 2012/ ..UPDATE... DISCUSSION... WELL DEFINED OUTFLOW BOUNDARY HAS PUSHED TO NEAR A PAWNEE TO JAY LINE...AND CONTINUES TO SLOWLY WORK SOUTHWARD. ISOLATED CONVECTION HAS RECENTLY FIRED ALONG THE BOUNDARY BOTH ACROSS NE OK / NW AR BUT ALSO FURTHER WEST ACROSS NW OK. WILL MAINTAIN LOW PRECIP CHANCES OVERNIGHT THOUGH COVERAGE WILL LIKELY REMAIN RATHER LOW. ALSO UPDATED WINDS NEARER THE RUC OUTPUT WHICH IS SLIGHTLY FURTHER SOUTH WITH THE BOUNDARY OVERNIGHT. THIS BRINGS MORE OF A NORTHEASTERLY WIND ACROSS THE TULSA METRO...WHICH WILL IMPACT THE PLACEMENT OF THE URBAN HEAT ISLAND PLUME AND CORRESPONDING ADJUSTMENTS WERE MADE WHICH LOWERED KTUL AND RAISED KRVS VALUES. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...EXCESSIVE HEAT WARNING UNTIL 7 PM FRIDAY FOR OKZ054-OKZ055- OKZ056-OKZ057-OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-OKZ063- OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-OKZ069-OKZ070-OKZ071- OKZ072-OKZ073-OKZ074. HEAT ADVISORY UNTIL 7 PM FRIDAY FOR OKZ049-OKZ053-OKZ075-OKZ076. AR...EXCESSIVE HEAT WARNING UNTIL 7 PM FRIDAY FOR ARZ001-ARZ010- ARZ019-ARZ029. HEAT ADVISORY UNTIL 7 PM FRIDAY FOR ARZ002-ARZ011-ARZ020. && $$ AVIATION...06
AREA FORECAST DISCUSSION
NWS PORTLAND OR
810 PM PDT SAT AUG 4 2012 .SYNOPSIS...AN UPPER RIDGE WILL REMAIN OVER THE PACIFIC NORTHWEST THROUGH SUNDAY...RESULTING IN ABOVE NORMAL TEMPERATURES INLAND. LOW MARINE CLOUDS ALONG THE COAST WILL KEEP TEMPERATURES MUCH COOLER SUNDAY THAN EXPERIENCED TODAY THOUGH. AN UPPER LEVEL DISTURBANCE MAY TRIGGER A FEW THUNDERSTORMS SUNDAY EVENING INTO SUNDAY NIGHT. A SLIGHT THREAT OF THUNDERSTORMS WILL CONTINUE NEAR THE CREST OF THE CASCADE MOUNTAINS FOR MONDAY AND TUESDAY AFTERNOONS. MORE SEASONAL TEMPERATURES WILL RETURN BY TUESDAY AND WEDNESDAY. && .SHORT TERM...SURFACE OBSERVATIONS AND RUC ANALYSIS INDICATE THE THERMALLY INDUCED TROUGH IS CURRENTLY DRAPED OVER WESTERN OREGON. HIGH TEMPERATURES TODAY GENERALLY RANGED IN THE 98F TO 103F RANGE FOR MUCH OF THE WILLAMETTE VALLEY. NUMEROUS RECORD HIGH TEMPERATURES WERE OBSERVED AROUND THE REGION. SEE THE RER HEADLINE ON THE PQR HOMEPAGE FOR DETAILS. TEMPERATURES ARE BEGINNING TO DROP THIS EVENING AND EXPECT THIS TREND TO CONTINUE OVERNIGHT. A SHORTWAVE TROUGH RESPONSIBLE FOR ELEVATED CONVECTION OVER CENTRAL CALIFORNIA AND NEVADA THIS EVENING WILL SPREAD PERIODS OF HIGH CLOUDS OVERHEAD TONIGHT. THIS WILL HELP TO REDUCE RADIATIONAL COOLING AND KEEP LOW TEMPERATURES HIGHER THAN LAST NIGHT FOR MANY AREAS. THE EXCEPTIONS TO THIS WILL BE ALONG THE COAST AND POSSIBLY ACROSS THE SOUTHERN WILLAMETTE VALLEY WHERE MARINE AIR WILL FILTER INTO THE REGION TO HELP TO COOL TEMPERATURES A BIT MORE. HOWEVER...IF HIGH CLOUD TRENDS CONTINUE...LOW TEMPERATURES CURRENTLY FORECAST MAY STILL BE TOO COOL. TEMPERATURES WILL ALSO STAY VERY WARM ACROSS AREA RIDGETOPS OVERNIGHT WHERE RADIATIONAL COOLING WILL BE MINIMIZED. I WILL NOT BE SURPRISED TO SEE A FEW OF THE MORE EXPOSED RAW STATIONS IN THE CASCADES STAY ABOVE 70F TO 75F OVERNIGHT. MAIN EDITS WERE TO TWEAK SKY COVER AND TEMPERATURES/DEWPOINT GRIDS OVER THE NEXT 24 HRS. THE REST OF THE INHERITED FORECAST APPEARS ON TRACK AS THE THERMALLY INDUCED TROUGH SHIFTS EAST OF THE CASCADES SUNDAY. THIS WILL RESULT IN SOME SEEPAGE OF MOISTURE AND COOLER TEMPERATURES INTO THE WILLAMETTE VALLEY SUNDAY...PARTICULARLY SOUTH OF SALEM. WHILE TEMPERATURES WILL BE 5 TO 10 DEGREES COOLER SUNDAY...IT WILL NOT FEEL A WHOLE TON COOLER THAN TODAY DUE TO A WARMER START AND DEWPOINTS RISING INTO THE UPPER 50S TO EVEN LOW 60S BY THE LATE AFTERNOON. THE AFOREMENTIONED SHORTWAVE TROUGH AXIS RESPONSIBLE FOR CONVECTION OVER CALIFORNIA IS STILL ON TRACK TO SHIFT NORTHWARD ACROSS THE AREA SUNDAY EVENING INTO SUNDAY NIGHT. AN ALTOCUMULUS/VIRGA STORM IS LIKELY IN STORE. THE MAIN QUESTION WILL BE WHETHER OR NOT A FEW THUNDERSTORMS ARE MIXED IN. IN GENERAL...THE MID LEVEL THETAE RIDGE AXIS AND MID LEVEL INSTABILITY WILL BE WEAKENING AS THEY SHIFT NORTHWARD ACROSS THE AREA...WHICH DOES NOT LOOK OVERLY PROMISING. NONETHELESS...THIS IS RATHER CLASSIC SCENARIO FOR ELEVATED THUNDER TO DEVELOP AND PERSIST SO LEFT THE INHERITED FORECAST AS IS. THE THUNDER THREAT APPEARS HIGHEST ACROSS THE SOUTH AND EAST. /NEUMAN .LONG TERM...THE PATTERN OF MORNING CLOUDS THEN AFTERNOON SUN WILL RETURN THROUGH THE EXTENDED PERIOD STARTING TUE NIGHT. A BROAD UPPER LEVEL TROUGH WILL REMAIN OVER THE WEST COAST...ALLOWING SOUTHWEST FLOW ALOFT AND ONSHORE FLOW AT THE SURFACE TO PERSIST INTO LATE NEXT WEEK. MODELS CONTINUE TO SHOW A SHORTWAVE WRAPPING AROUND THE PARENT LOW WED...POSSIBLE BRINGING A LITTLE DRIZZLE TO THE COAST AND DEEPENING THE MARINE LAYER. OTHERWISE...EXPECT TEMPS TO REMAIN NEAR NORMAL WITH HIGHS AT THE COAST IN THE MID 60S AND INLAND HIGHS IN THE LOWER TO MID 80S. /27 && .AVIATION...VFR CONDITIONS TONIGHT AND SUN AS HIGH PRES REMAINS OVER PAC NW. THERMAL TROUGH NEAR THE COASTLINE WILL PUSH INTO THE WILLAMETTE VALLEY LATE TONIGHT AND SUN AM...THEN PUSH OVER THE CASCADES SUN NIGHT. IFR STRATUS JUST OFFSHORE WILL PUSH ONSHORE BY MIDNIGHT...AND REMAIN THROUGH MOST OF SUN. ELSEWHERE...VARIABLE HIGH CLOUDS WILL DRIFT OVER REGION THROUGH SUN...WITH A 1 IN 4 CHANCE OF SEEING A TSTORM OVER THE CASCADES AFTER 19Z SUN. KPDX AND APPROACHES...VFR TONIGHT AND SUN...WITH VARIABLE HIGH CLOUDS AFTER MIDNIGHT THROUGH SUN AFTERNOON. && .MARINE...HIGH PRES WILL REMAIN ANCHORED OVER THE NE PAC THROUGH THE WEEK. THERMAL LOW PRES ON COAST WILL MOVE FURTHER INLAND TONIGHT. WINDS REMAIN BELOW 15 KT...WITH SEAS 3 TO 5 FT THROUGH WED. && .PQR WATCHES/WARNINGS/ADVISORIES... OR... HEAT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR CASCADE FOOTHILLS IN LANE COUNTY-CENTRAL COAST RANGE OF WESTERN OREGON- CENTRAL WILLAMETTE VALLEY-COAST RANGE OF NORTHWEST OREGON- GREATER PORTLAND METRO AREA-LOWER COLUMBIA-NORTHERN OREGON CASCADE FOOTHILLS-SOUTH WILLAMETTE VALLEY-UPPER HOOD RIVER VALLEY-WESTERN COLUMBIA RIVER GORGE. WA...HEAT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR GREATER VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ COUNTY-SOUTH WASHINGTON CASCADE FOOTHILLS-WESTERN COLUMBIA RIVER GORGE-WILLAPA HILLS. PZ...NONE. && MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1101 PM EDT SAT AUG 4 2012 .SYNOPSIS... AN APPROACHING COLD FRONT WILL BRING AN INCREASE IN HUMIDITY AND SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS THIS EVENING...AND AGAIN ON SUNDAY. SOME OF WHICH MAY BE STRONG TO SEVERE ON SUNDAY...BEFORE DRIER AIR BUILDS IN FOR EARLY NEXT WEEK. OVERALL THE PATTERN FOR EASTERN NORTH AMERICA IS IN TRANSITION WITH THE EXPECTED DEVELOPMENT OF A BROAD TROUGH OVER THE NEXT 4 TO 8 DAYS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... SCT-BKN ALTO CU CLOUDS /THE REMNANTS OF EARLIER CONVECTION/ WILL CONTINUE TO DRIFT EAST ACROSS THE FCST AREA OVER THE NEXT SEVERAL HOURS. A SHIELD OF THICKENING CIRRUS BLOWING OFF THE WRN OHIO MCS WILL SPREAD INTO THE WRN MTNS BY 05Z. THE EASTERN EDGE OF A NORTH/SOUTH BAND OF ANOMALOUSLY HIGH PWATS OF NEARLY 2 INCHES WILL EDGE INTO THE FAR NW ZONES TWD DAYBREAK SUNDAY...ACCOMPANIED BY INCREASING LLVL SOUTH SOUTHWESTERLY SHEAR. 850 MB WINDS WILL INCREASE TO AROUND 35 KTS OVERNIGHT...WHICH RANKS ABOUT 3 STANDARD DEVIATIONS FROM NORMAL. THIS INCREASING LOW LEVEL FORCING AND HIGH AMOUNT OF MOISTURE WILL SUPPORT ANOTHER FEW CLUSTERS OF LATE NIGHT SHOWERS AND SCATTERED TSRA MOVING ACROSS PORTIONS OF THE CWA WELL AFTER MIDNIGHT. A LINE OF STRONG TO SVR TSRA WAS RACING EAST TWD NCENT OHIO AT AROUND 45 KTS LATE THIS EVENING. THIS LINE OF INTENSE CONVECTION SHOULD WEAKEN A BIT LATE TONIGHT AS IT MOVES INTO THE SLIGHTLY LESS UNSTABLE AIRMASS ACROSS CENTRAL AND WRN PENN. LINEAR EXTRAPOLATION OF THE OHIO SQUALL LINE PLACES IT ACROSS THE MTNS OF WRN PENN BY AROUND 07Z...AND NEAR THE SUSQ MAINSTEM AROUND 09Z SUNDAY. AGAIN...PRIOR TO THIS WEAKENING LINE OF TSRA...ANOMALOUSLY STRONG 850 MB MOISTURE FLUX SHOWN BY THE SREF WILL SUPPORT ADDITIONAL...DISCRETE TSRA MOVING NE IN ITS ADVANCE. SHORT RANGE MODELS SUCH AS THE HRRR AND 4 KM NAM CONCUR ON THE REGENERATION OF CONVECTION IN THE FORM OF SCATTERED TSRA WELL AFTER MIDNIGHT...BUT DON/T SEEM TO BE LOCKING ONTO THE THE CURRENT OHIO MCS AT ALL. HRRR FIRES UP TSRA ACROSS THE LAURELS AND CENTRAL MTNS...WHILE IN CONTRAST THE 4 KM NAM SHOWS A FAIRLY LARGE AREA OF SHOWERS/TSRA MOVING NE NEAR AND JUST TO THE SE OF INTERSTATE 81 AFTER 05Z. LOWS WILL RANGE FROM THE MID TO UPPER 60S ACROSS THE MTN LOCATIONS...TO THE LOWER 70S IN THE SOUTHERN VALLEYS AND LOWER SUSQ REGION. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... FRONTAL SYSTEM TO OUR WEST AND THE RIDGE OVER THE ATLANTIC WILL SEND A DEEP PLUME OF MOISTURE WITH 2-3 SIGMA ABOVE NORMAL PW EAST ACRS THE REGION. WHILE THE STRONGEST SWRLY LLVL FLOW WILL LIKELY LIFT NE OF OUR AREA...THE FLOW WILL BE RATHER STRONG FOR EARLY AUG. CAPE VALUES ARE GOOD FOR SEVERE WEATHER BUT NOT OVERLY IMPRESSIVE. BUT OVER 20KTS OF 1KM SHEAR WITH 1200 TO 1800JKG-1 IMPLIES DEEP UPDRAFTS AND GOOD SHEAR. THIS SHOULD FAVOR THE DEVELOPMENT...MAINLY FROM MID AFTERNOON INTO EVENING OF STRONG TO POTENTIAL SEVERE THUNDERSTORMS...FAVORING MORE LINEAR SYSTEMS WITH POTENTIAL BOW DEVELOPMENT. MOST GUIDANCE SHOWS STRONG LOW-LEVEL SHEAR WHICH WILL REQUIRE MONITORING. MULTI-CELLULAR DAY LIKELY WITH BOWING SEGMENTS HIGH PROBABILITY THINKING AT THIS TIME. MOISTURE FLUX...OFTEN ALIGNS WELL WITH OUR BETTER SEVERE EVENTS PEAKS 1800 UTC SUNDAY TO ABOUT 0000 UTC MONDAY. GOOD BET STRONG STORMS FROM ABOUT 2 PM SUNDAY UNTIL 10 PM IN EAST. && .LONG TERM /MONDAY THROUGH SATURDAY/... BY MONDAY MORNING...COLD FRONT WILL BE JUST SE OF CWA. WILL TAKE SOME TIME TO CLEAR OUT RESIDUAL MOISTURE IN SOUTHEAST. BUT WITH WESTERLY WINDS...DRIER AIR WILL EVENTUALLY WORK INTO THE BOUNDARY LAYER IN THE SE. PW FALLS BELOW NORMAL STATE WIDE MONDAY. CENTER OF SFC HIGH SETTLES OVER PA MON NIGHT/TUE KEEPING FORECAST DRY. WEAK WAVE OVER SE U.S. SLIDES UP THE COAST FOR WED/THU...NUDGING MOISTURE BACK INTO CWA. SO INTRODUCED SLIGHT CHANCE FOR A TSTM WED/THU AS HUMIDITY BEGINS TO INCREASE. MORE POTENT TROUGH APPROACHES IN NW FLOW FOR THU NIGHT-FRI NIGHT. MODELS HANDLING THIS FEATURE WELL...THOUGH GFS TRIES TO LIFT TROUGH NORTHWARD. EITHER WAY...CHANCE OF SHOWERS/TSTMS FITS THE BILL BEFORE A MAINLY DRY WEEKEND. TEMPERATURES WILL BE NEAR NORMAL TO START THE WEEK...THEN SLOWLY RISE BACK ABOVE NORMAL FOR MIDWEEK. AS HUMIDITY INCREASES LATE WEEK AHEAD OF APPROACHING TROUGH...TEMPS AGAIN GET A BIT MUGGY - EVEN THOUGH THEY REMAIN JUST A FEW DEGREES ABOVE NORMAL. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS WITH JUST SOME SCT-BKN MID CLOUDS WERE PRESENT OVER THE REGION THIS EVENING. WEAK WARM FRONTAL BOUNDARY /MARKING THE LEADING EDGE OF HIGHER PWAT AIR/ SLIDES THROUGH OVERNIGHT...KEEPING CHANCE FOR A SHOWER/TSRA IN THE FCST...ESPECIALLY WELL AFTER MIDNIGHT ACROSS THE WRN MTNS. THIS WILL ALSO BRING MVFR CIGS INTO WESTERN SECTIONS LATER TONIGHT AS WELL AS MVFR VSBY ACROSS MUCH OF CWA. POTENT COLD FRONT APPROACHES SUNDAY. EXPECT SCT /HIT AND MISS/ TSTMS TO DEVELOP EARLY IN THE DAY. AS COLD FRONT MOVES THROUGH IN THE AFTERNOON AND EVENING...TSTMS WILL LIKELY ORGANIZE INTO A MORE SOLID LINE OF CONVECTION - WITH POTENTIALLY WIDESPREAD STRONG WINDS. LINE SHOULD IMPACT NW BY EARLY/MID AFTERNOON AND REACH SUSQ VALLEY DURING THE EVENING HOURS. OUTLOOK... .SUN...A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS...ESPECIALLY SUNDAY PM AS A COLD FRONT MOVES THROUGH. .MON...CHC OF A SHOWER OR STORM EARLY...THEN MAINLY VFR. .TUE-THU...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT/RXR LONG TERM...RXR AVIATION...LA CORTE/RXR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
533 PM EDT FRI AUG 3 2012 .SYNOPSIS... CIRCULATION AROUND HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL KEEP THE SOUTHERN APPALACHIAN REGION WARM AND HUMID THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO SLOWLY SWEEP ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA EARLY NEXT WEEK...POSSIBLY BECOMING STATIONARY AND LINGERING INTO LATE IN THE WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... 2130 UTC UPDATE...POPS WERE LOWERED ALONG THE TN BORDER IN THE CENTRAL AND SOUTHERN NC MOUNTAINS PER RADAR TRENDS...AND RAISED IN THE NORTHERN NC MOUNTAINS. QPF WAS LOWERED IN THE FOOTHILLS AND PIEDMONT. SKY COVER WAS UPDATED FORM THE LATEST VISIBLE IMAGERY. PREVIOUS DISCUSSION...CONVECTION HAS BEGUN TO DEVELOP OVER THE SOUTHWEST AND CENTRAL NC MTNS. LAYER RH VALUES ARE THE HIGHEST IN THIS PART OF THE FORECAST AREA...AND IT/S CLOSET TO THE APPROACHING SHORTWAVE TROUGH WHICH CURRENTLY EXTENDS FROM CENTRAL KY TO ERN TN. THE FEATURE ITSELF IS QUITE WEAK AND THE EFFECTIVE BULK SHEAR ACROSS THE REGION IS WELL UNDER 20 KTS. THEREFORE DIFFERENTIAL HEATING AND LLVL MASS CONVERGENCE SHOULD BE THE MAIN DRIVERS FOR CONVECTION THIS EVENING. THE LATEST HI-RES NUMERICAL MODEL RUNS ARE MORE VARIED THAN WHAT I SAW THIS MORNING. THE WRF-ARW AND THE HRRR BOTH DEVELOP CONVECTION OVER PARTS OF THE FA...BUT IT/S NOT LOOKING AS ORGANIZED AS EARLIER. THE 12 UTC 4KM SPC WRF ON THE OTHER HAND HAS A LARGE AREA OF CONVECTION OVER THE WESTERN UPSTATE AND NE GA THIS EVENING. THE 12 UTC NAM HAS STRONG LLVL CONVERGENCE THIS EVENING AND ALSO DEVELOPS INTENSE SLOW MOVING CONVECTION OVER THE UPSTATE. OVERALL...THE IDEA OF LIKELY POPS SLOWLY SPREADING FROM WEST TO EAST ACROSS THE FA THE REST OF THE AFN AND EVENING STILL LOOKS GOOD. DCAPE VALUES ARE WELL OVER 1000 J/KG ACROSS THE UPSTATE AND NE GA...AND PULSE SEVERE STORMS ARE A GOOD BET AGAIN THIS EVENING. PULSE SEVERE WON/T BE LIKELY OVER THE NC MTNS AND FOOTHILLS...BUT EVEN THOUGH CURRENT DCAPE VALUES AREN/T THAT GREAT...I STILL SUSPECT WE/LL SEE A FEW SEVERE STORMS ALONG THE I-77 URBAN CORRIDOR. VERY HEAVY RAIN IS ALSO POSSIBLE IS SPOTS AND ISOLATED FLASH FLOODING IS POSSIBLE. LATER TONIGHT WIDESPREAD LOW CLOUDS SHOULD DEVELOP ACROSS MOST OF THE FA. ON SATURDAY THE UPPER TROUGH WEAKENS QUICKLY AS THE ATLANTIC RIDGE STARTS TO BUILD BACK INTO THE REGION. THE WEAKENING OF THE TROUGH IS A LITTLE FASTER THAN WHAT WE/D BEEN EXPECTING. LAYER RH/S WILL REMAIN HIGH AND EVEN WITH VERY WEAK FORCING...THERE SHOULD BE PLENTY OF CONVECTION OVER THE HIGH TERRAIN AND A LITTLE LESS OUT ACROSS THE FOOTHILLS AND PIEDMONT. THE SEVERE AND FLOODING RISK DON/T LOOK AS GREAT TOMORROW. INTERESTINGLY...THE STRONGEST FORCING OF THE DAY COULD COME IN THE FORM OF THE SEA-BREEZE FRONT WHICH THE NAM BRINGS INTO THE SE ZONES EARLY IN THE EVENING. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 145 PM EDT...EXPECT SOME ONGOING SCATTERED CONVECTION SATURDAY EVENING TO WANE RATHER QUICKLY AS SUBTROPICAL RIDGE BUILDS WESTWARD INTO THE AREA SAT NIGHT. HENCE...THE SAT OVERNIGHT THROUGH SUNDAY MORNING IS EXPECTED TO BE TRANQUIL. ON SUNDAY AFTERNOON...UPSLOPE FLOW AND THE APPROACH OF A WEAK COLD FRONT FROM THE NW SHOULD TRIGGER SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE MOUNTAINS. ONLY ISOLATED TO WIDELY SCATTERED ACTIVITY IS EXPECTED ELSEWHERE. THE MODELS BRING THE FRONTAL BOUNDARY INTO THE MOUNTAINS SUNDAY NIGHT WHICH NECESSITATES MAINTAINING AT LEAST SCATTERED POPS THERE. ON MONDAY...THE FRONT IS FORECAST TO LAY OUT ACROSS THE WESTERN CAROLINAS INTO NE GA WHICH SHOULD BE A FOCAL POINT FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MAXIMUM TEMPERATURES ARE EXPECTED TO BE NEAR CLIMO WITH MIN TEMPERATURES ABOUT A CATEGORY ABOVE AVERAGE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 1 PM EDT FRIDAY...THE MEDIUM RANGE IS EXPECTED TO FEATURE SOME DEGREE OF BROAD UPPER TROFFING OVER THE EASTERN U.S. WITH PERHAPS SOME AMPLIFICATION IN THE TROUGH TOWARD THE END OF THE PERIOD. THE PERSISTENT TROUGH AND THE PRESENCE OF THE FRONT WILL CONTINUE TO TRIGGER SHOWERS AND THUNDERSTORMS THROUGH TUE...WITH AN UPTICK DURING THE FAVORED AFTERNOON AND EVENING TIME PERIOD. THERE IS SOME DIVERGENCE IN THE GUIDANCE IN REGARD TO HOW FAR SOUTH THE AFOREMENTIONED FRONT GOES. THE ECM CAMP TAKES THE FRONTAL BOUNDARY JUST SOUTH OF THE AREA ON WED AND BRINGS SOMEWHAT DRYER INTO THE REGION FOR WED INTO THU. THIS WOULD PRODUCE A DECREASE IN SHOWER/THUNDERSTORM ACTIVITY FOR WED INTO THU. ON THE OTHER HAND... THE GFS HANGS UP THE BOUNDARY OVER THE AREA THROUGH THE PERIOD WITH A CONTINUATION OF ENHANCED SHOWER AND THUDNERSTORM ACTIVITY THROUGH THE END OF THE WEEK. HPC SIDED WITH THE ECM FRONTAL POSITION. WE GENERALLY STAYED CLOSE TO HPC GUIDANCE WITH HIGHER THAN CLIMO POPS FOR TUE AND THEN SOMEWHAT LOWER THAN CLIMO...ESPECIALLY ACROSS THE MOUNTAINS FOR WED. BASICALLY CLIMO POPS RETURN FOR THE END OF THE WEEK. USED A BLEND OF HPC/GMOS FOR TEMPS WHICH ESSENTIALLY IS CLOSE TO CLIMO. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... AT KCLT...SHOWERS ARE BEGINNING TO DEVELOP OVER THE FOOTHILLS ABOUT 80 MI WEST OF THE AIRFIELD. WHILE CONVECTION IS EXPECTED TO BUILD OVER THE FOOTHILLS THE REST OF THE AFTN...IT WILL TAKE A WHILE FOR STORMS TO DEVELOP OUT ACROSS THE PIEDMONT. HOWEVER...MANY NUMERICAL MODELS ARE BULLISH ON DEVELOPING CONVECTION...AND I THINK THAT BY 22 UTC TSTMS ARE LIKELY TO DEVELOP IN PLACE OVER THE REGION. THE TEMPO GROUP FOR CONVECTION FROM 22-02 UTC STILL LOOKS GOOD FOR THIS REASON. THE MODEL GUIDANCE ALSO IS STRONGLY SUGGESTING THAT STRATUS WILL DEVELOP OVERNIGHT. WITH DEWPOINTS GETTING UP INTO THE LOW 70S AND EXPECTED WIDESPREAD UPSTREAM PRECIPITATION THIS LOOKS REASONABLE AND AN 800 FOOT CIG HAS BEEN INTRODUCED INTO THE TAF VERY LATE TONIGHT THROUGH MID MORNING ON SATURDAY. AND ELSEWHERE...SHRA/TSTMS ARE BEGINNING TO DEVELOP IN THE VCNTY OF THE KAVL AIRFIELD. VCTS HAS BEEN ADDED FOR THE NEXT FEW HOURS WITH PREVAILING THUNDER FROM LATE AFTN INTO THE EARLY EVENING AS IT LOOKS TO BE A STORMY EVENING IN THE MTNS AHEAD OF AN APPROACHING UPPER LOW. ONCE CONVECTION ENDS LATER TONIGHT LOW CLOUDS AND VALLEY FOG SHOULD DEVELOP. THE TIMING WILL DEPEND UPON HOW MUCH RAIN FALLS AT THE AIRFIELD AND HOW QUICKLY MID AND HIGH CLOUDS THIN. THE SAME APPLIES TO THE REST OF THE REGION...THOUGH IT WILL TAKE TSTMS A FEW HOURS YET TO BEGIN TO DEVELOP OUTSIDE THE MTNS. TEMPO OR PREVAILING GROUPS WILL PROBABLY BE NEEDED AT MOST AIRFIELDS...BUT CONFIDENCE ISN/T HIGH ENOUGH TO DO THAT YET OUTSIDE THE MTNS. WITH LOW 70S DEWPOINTS...15 KTS OF SLY LLVL FLOW AND MORE RAIN THIS EVENING...STRATUS IS A GOOD BET TONIGHT. BASED ON THE AMOUNT OF MIXING AND 800 FOOT DECK SEEMS REASONABLE. OUTLOOK...ISO/SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...NED NEAR TERM...JAT/MCAVOY SHORT TERM...LG LONG TERM...LG AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
349 PM EDT FRI AUG 3 2012 .SYNOPSIS... CIRCULATION AROUND HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL KEEP THE SOUTHERN APPALACHIAN REGION WARM AND HUMID THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO SLOWLY SWEEP ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA EARLY NEXT WEEK...POSSIBLY BECOMING STATIONARY AND LINGERING INTO LATE IN THE WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... 1930 UTC UPDATE...POPS WERE INCREASED ALONG THE TN BORDER IN THE CENTRAL AND SOUTHERN NC MOUNTAINS PER RADAR TRENDS. SKY COVER WAS UPDATED FORM THE LATEST VISIBLE IMAGERY. PREVIOUS DISCUSSION...CONVECTION HAS BEGUN TO DEVELOP OVER THE SOUTHWEST AND CENTRAL NC MTNS. LAYER RH VALUES ARE THE HIGHEST IN THIS PART OF THE FORECAST AREA...AND IT/S CLOSET TO THE APPROACHING SHORTWAVE TROUGH WHICH CURRENTLY EXTENDS FROM CENTRAL KY TO ERN TN. THE FEATURE ITSELF IS QUITE WEAK AND THE EFFECTIVE BULK SHEAR ACROSS THE REGION IS WELL UNDER 20 KTS. THEREFORE DIFFERENTIAL HEATING AND LLVL MASS CONVERGENCE SHOULD BE THE MAIN DRIVERS FOR CONVECTION THIS EVENING. THE LATEST HI-RES NUMERICAL MODEL RUNS ARE MORE VARIED THAN WHAT I SAW THIS MORNING. THE WRF-ARW AND THE HRRR BOTH DEVELOP CONVECTION OVER PARTS OF THE FA...BUT IT/S NOT LOOKING AS ORGANIZED AS EARLIER. THE 12 UTC 4KM SPC WRF ON THE OTHER HAND HAS A LARGE AREA OF CONVECTION OVER THE WESTERN UPSTATE AND NE GA THIS EVENING. THE 12 UTC NAM HAS STRONG LLVL CONVERGENCE THIS EVENING AND ALSO DEVELOPS INTENSE SLOW MOVING CONVECTION OVER THE UPSTATE. OVERALL...THE IDEA OF LIKELY POPS SLOWLY SPREADING FROM WEST TO EAST ACROSS THE FA THE REST OF THE AFN AND EVENING STILL LOOKS GOOD. DCAPE VALUES ARE WELL OVER 1000 J/KG ACROSS THE UPSTATE AND NE GA...AND PULSE SEVERE STORMS ARE A GOOD BET AGAIN THIS EVENING. PULSE SEVERE WON/T BE LIKELY OVER THE NC MTNS AND FOOTHILLS...BUT EVEN THOUGH CURRENT DCAPE VALUES AREN/T THAT GREAT...I STILL SUSPECT WE/LL SEE A FEW SEVERE STORMS ALONG THE I-77 URBAN CORRIDOR. VERY HEAVY RAIN IS ALSO POSSIBLE IS SPOTS AND ISOLATED FLASH FLOODING IS POSSIBLE. LATER TONIGHT WIDESPREAD LOW CLOUDS SHOULD DEVELOP ACROSS MOST OF THE FA. ON SATURDAY THE UPPER TROUGH WEAKENS QUICKLY AS THE ATLANTIC RIDGE STARTS TO BUILD BACK INTO THE REGION. THE WEAKENING OF THE TROUGH IS A LITTLE FASTER THAN WHAT WE/D BEEN EXPECTING. LAYER RH/S WILL REMAIN HIGH AND EVEN WITH VERY WEAK FORCING...THERE SHOULD BE PLENTY OF CONVECTION OVER THE HIGH TERRAIN AND A LITTLE LESS OUT ACROSS THE FOOTHILLS AND PIEDMONT. THE SEVERE AND FLOODING RISK DON/T LOOK AS GREAT TOMORROW. INTERESTINGLY...THE STRONGEST FORCING OF THE DAY COULD COME IN THE FORM OF THE SEA-BREEZE FRONT WHICH THE NAM BRINGS INTO THE SE ZONES EARLY IN THE EVENING. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 145 PM EDT...EXPECT SOME ONGOING SCATTERED CONVECTION SATURDAY EVENING TO WANE RATHER QUICKLY AS SUBTROPICAL RIDGE BUILDS WESTWARD INTO THE AREA SAT NIGHT. HENCE...THE SAT OVERNIGHT THROUGH SUNDAY MORNING IS EXPECTED TO BE TRANQUIL. ON SUNDAY AFTERNOON...UPSLOPE FLOW AND THE APPROACH OF A WEAK COLD FRONT FROM THE NW SHOULD TRIGGER SCATTERED TO NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE MOUNTAINS. ONLY ISOLATED TO WIDELY SCATTERED ACTIVITY IS EXPECTED ELSEWHERE. THE MODELS BRING THE FRONTAL BOUNDARY INTO THE MOUNTAINS SUNDAY NIGHT WHICH NECESSITATES MAINTAINING AT LEAST SCATTERED POPS THERE. ON MONDAY...THE FRONT IS FORECAST TO LAY OUT ACROSS THE WESTERN CAROLINAS INTO NE GA WHICH SHOULD BE A FOCAL POINT FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MAXIMUM TEMPERATURES ARE EXPECTED TO BE NEAR CLIMO WITH MIN TEMPERATURES ABOUT A CATEGORY ABOVE AVERAGE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 1 PM EDT FRIDAY...THE MEDIUM RANGE IS EXPECTED TO FEATURE SOME DEGREE OF BROAD UPPER TROFFING OVER THE EASTERN U.S. WITH PERHAPS SOME AMPLIFICATION IN THE TROUGH TOWARD THE END OF THE PERIOD. THE PERSISTENT TROUGH AND THE PRESENCE OF THE FRONT WILL CONTINUE TO TRIGGER SHOWERS AND THUNDERSTORMS THROUGH TUE...WITH AN UPTICK DURING THE FAVORED AFTERNOON AND EVENING TIME PERIOD. THERE IS SOME DIVERGENCE IN THE GUIDANCE IN REGARD TO HOW FAR SOUTH THE AFOREMENTIONED FRONT GOES. THE ECM CAMP TAKES THE FRONTAL BOUNDARY JUST SOUTH OF THE AREA ON WED AND BRINGS SOMEWHAT DRYER INTO THE REGION FOR WED INTO THU. THIS WOULD PRODUCE A DECREASE IN SHOWER/THUNDERSTORM ACTIVITY FOR WED INTO THU. ON THE OTHER HAND... THE GFS HANGS UP THE BOUNDARY OVER THE AREA THROUGH THE PERIOD WITH A CONTINUATION OF ENHANCED SHOWER AND THUDNERSTORM ACTIVITY THROUGH THE END OF THE WEEK. HPC SIDED WITH THE ECM FRONTAL POSITION. WE GENERALLY STAYED CLOSE TO HPC GUIDANCE WITH HIGHER THAN CLIMO POPS FOR TUE AND THEN SOMEWHAT LOWER THAN CLIMO...ESPECIALLY ACROSS THE MOUNTAINS FOR WED. BASICALLY CLIMO POPS RETURN FOR THE END OF THE WEEK. USED A BLEND OF HPC/GMOS FOR TEMPS WHICH ESSENTIALLY IS CLOSE TO CLIMO. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... AT KCLT...SHOWERS ARE BEGINNING TO DEVELOP OVER THE FOOTHILLS ABOUT 80 MI WEST OF THE AIRFIELD. WHILE CONVECTION IS EXPECTED TO BUILD OVER THE FOOTHILLS THE REST OF THE AFTN...IT WILL TAKE A WHILE FOR STORMS TO DEVELOP OUT ACROSS THE PIEDMONT. HOWEVER...MANY NUMERICAL MODELS ARE BULLISH ON DEVELOPING CONVECTION...AND I THINK THAT BY 22 UTC TSTMS ARE LIKELY TO DEVELOP IN PLACE OVER THE REGION. THE TEMPO GROUP FOR CONVECTION FROM 22-02 UTC STILL LOOKS GOOD FOR THIS REASON. THE MODEL GUIDANCE ALSO IS STRONGLY SUGGESTING THAT STRATUS WILL DEVELOP OVERNIGHT. WITH DEWPOINTS GETTING UP INTO THE LOW 70S AND EXPECTED WIDESPREAD UPSTREAM PRECIPITATION THIS LOOKS REASONABLE AND AN 800 FOOT CIG HAS BEEN INTRODUCED INTO THE TAF VERY LATE TONIGHT THROUGH MID MORNING ON SATURDAY. AND ELSEWHERE...SHRA/TSTMS ARE BEGINNING TO DEVELOP IN THE VCNTY OF THE KAVL AIRFIELD. VCTS HAS BEEN ADDED FOR THE NEXT FEW HOURS WITH PREVAILING THUNDER FROM LATE AFTN INTO THE EARLY EVENING AS IT LOOKS TO BE A STORMY EVENING IN THE MTNS AHEAD OF AN APPROACHING UPPER LOW. ONCE CONVECTION ENDS LATER TONIGHT LOW CLOUDS AND VALLEY FOG SHOULD DEVELOP. THE TIMING WILL DEPEND UPON HOW MUCH RAIN FALLS AT THE AIRFIELD AND HOW QUICKLY MID AND HIGH CLOUDS THIN. THE SAME APPLIES TO THE REST OF THE REGION...THOUGH IT WILL TAKE TSTMS A FEW HOURS YET TO BEGIN TO DEVELOP OUTSIDE THE MTNS. TEMPO OR PREVAILING GROUPS WILL PROBABLY BE NEEDED AT MOST AIRFIELDS...BUT CONFIDENCE ISN/T HIGH ENOUGH TO DO THAT YET OUTSIDE THE MTNS. WITH LOW 70S DEWPOINTS...15 KTS OF SLY LLVL FLOW AND MORE RAIN THIS EVENING...STRATUS IS A GOOD BET TONIGHT. BASED ON THE AMOUNT OF MIXING AND 800 FOOT DECK SEEMS REASONABLE. OUTLOOK...ISO/SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...NED NEAR TERM...JAT/MCAVOY SHORT TERM...LG LONG TERM...LG AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
331 PM EDT FRI AUG 3 2012 .SYNOPSIS... CIRCULATION AROUND HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL KEEP THE SOUTHERN APPALACHIAN REGION WARM AND HUMID THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO SLOWLY SWEEP ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA EARLY NEXT WEEK...POSSIBLY BECOMING STATIONARY AND LINGERING INTO LATE IN THE WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... 1930 UTC UPDATE...POPS WERE INCREASED ALONG THE TN BORDER IN THE CENTRAL AND SOUTHERN NC MOUNTAINS PER RADAR TRENDS. SKY COVER WAS UPDATED FORM THE LATEST VISIBLE IMAGERY. PREVIOUS DISCUSSION...CONVECTION HAS BEGUN TO DEVELOP OVER THE SOUTHWEST AND CENTRAL NC MTNS. LAYER RH VALUES ARE THE HIGHEST IN THIS PART OF THE FORECAST AREA...AND IT/S CLOSET TO THE APPROACHING SHORTWAVE TROUGH WHICH CURRENTLY EXTENDS FROM CENTRAL KY TO ERN TN. THE FEATURE ITSELF IS QUITE WEAK AND THE EFFECTIVE BULK SHEAR ACROSS THE REGION IS WELL UNDER 20 KTS. THEREFORE DIFFERENTIAL HEATING AND LLVL MASS CONVERGENCE SHOULD BE THE MAIN DRIVERS FOR CONVECTION THIS EVENING. THE LATEST HI-RES NUMERICAL MODEL RUNS ARE MORE VARIED THAN WHAT I SAW THIS MORNING. THE WRF-ARW AND THE HRRR BOTH DEVELOP CONVECTION OVER PARTS OF THE FA...BUT IT/S NOT LOOKING AS ORGANIZED AS EARLIER. THE 12 UTC 4KM SPC WRF ON THE OTHER HAND HAS A LARGE AREA OF CONVECTION OVER THE WESTERN UPSTATE AND NE GA THIS EVENING. THE 12 UTC NAM HAS STRONG LLVL CONVERGENCE THIS EVENING AND ALSO DEVELOPS INTENSE SLOW MOVING CONVECTION OVER THE UPSTATE. OVERALL...THE IDEA OF LIKELY POPS SLOWLY SPREADING FROM WEST TO EAST ACROSS THE FA THE REST OF THE AFN AND EVENING STILL LOOKS GOOD. DCAPE VALUES ARE WELL OVER 1000 J/KG ACROSS THE UPSTATE AND NE GA...AND PULSE SEVERE STORMS ARE A GOOD BET AGAIN THIS EVENING. PULSE SEVERE WON/T BE LIKELY OVER THE NC MTNS AND FOOTHILLS...BUT EVEN THOUGH CURRENT DCAPE VALUES AREN/T THAT GREAT...I STILL SUSPECT WE/LL SEE A FEW SEVERE STORMS ALONG THE I-77 URBAN CORRIDOR. VERY HEAVY RAIN IS ALSO POSSIBLE IS SPOTS AND ISOLATED FLASH FLOODING IS POSSIBLE. LATER TONIGHT WIDESPREAD LOW CLOUDS SHOULD DEVELOP ACROSS MOST OF THE FA. ON SATURDAY THE UPPER TROUGH WEAKENS QUICKLY AS THE ATLANTIC RIDGE STARTS TO BUILD BACK INTO THE REGION. THE WEAKENING OF THE TROUGH IS A LITTLE FASTER THAN WHAT WE/D BEEN EXPECTING. LAYER RH/S WILL REMAIN HIGH AND EVEN WITH VERY WEAK FORCING...THERE SHOULD BE PLENTY OF CONVECTION OVER THE HIGH TERRAIN AND A LITTLE LESS OUT ACROSS THE FOOTHILLS AND PIEDMONT. THE SEVERE AND FLOODING RISK DON/T LOOK AS GREAT TOMORROW. INTERESTINGLY...THE STRONGEST FORCING OF THE DAY COULD COME IN THE FORM OF THE SEA-BREEZE FRONT WHICH THE NAM BRINGS INTO THE SE ZONES EARLY IN THE EVENING. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 145 PM EDT...EXPECT SOME ONGOING SCATTERED CONVECTION SATURDAY EVENING TO WANE RATHER QUICKLY AS SUBTROPICAL RIDGE BUILDS WESTWARD INTO THE AREA SAT NIGHT. HENCE...THE SAT OVERNIGHT THROUGH SUNDAY MORNING IS EXPECTED TO BE TRANQUIL. ON SUNDAY AFTERNOON...UPSLOPE FLOW AND THE APPROACH OF A WEAK COLD FRONT FROM THE NW SHOULD TRIGGER SCATTERED TO NUMEROUS SHOWERS/THUDNERSTORMS ACROSS THE MOUNTAINS. ONLY ISOLATED TO WIDELY SCATTERED ACTIVITY IS EXPECTED ELSEWHERE. THE MODELS BRING THE FRONTAL BOUNDARY INTO THE MOUNTAINS SUNDAY NIGHT WHICH NECESSITATES MAINTAINING AT LEAST SCATTERED POPS THERE. ON MONDAY...THE FRONT IS FORECAST TO LAY OUT ACROSS THE WESTERN CAROLINAS INTO NE GA WHICH SHOULD BE A FOCAL POINT FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MAXIMUM TEMPERATURES ARE EXPECTED TO BE NEAR CLIMO WITH MIN TEMPERATURES ABOUT A CATEGORY ABOVE AVERAGE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 1 PM EDT FRIDAY...THE MEDIUM RANGE IS EXPECTED TO FEATURE SOME DEGREE OF BROAD UPPER TROFFING OVER THE EASTERN U.S. WITH PERHAPS SOME AMPLIFICATION IN THE TROUGH TOWARD THE END OF THE PERIOD. THE PERSISTENT TROUGH AND THE APPROACH OF A WEAK COLD FRONT WILL CONTINUE TO TRIGGER SHOWERS AND THUNDERSTORMS THROUGH TUE...WITH AN UPTICK DURING THE FAVORED AFTERNOON AND EVENING TIME PERIOD. THERE IS SOME DIVERGENCE IN THE GUIDANCE IN REGARD TO HOW FAR SOUTH THE AFOREMENTIONED FRONT GOES. THE ECM CAMP TAKES THE FRONTAL BOUNDARY JUST SOUTH OF THE AREA ON WED AND BRINGS SOMEWHAT DRYER INTO THE REGION FOR WED INTO THU. THIS WOULD PRODUCE A DECREASE IN SHOWER/THUNDERSTORM ACTIVITY FOR WED INTO THU. ON THE OTHER HAND... THE GFS HANGS UP THE BOUNDARY OVER THE AREA THROUGH THE PERIOD WITH A CONTINUATION OF ENHANCED SHOWER AND THUDNERSTORM ACTIVITY THROUGH THE END OF THE WEEK. HPC SIDED WITH THE ECM FRONTAL POSITION. WE GENERALLY STAYED CLOSE TO HPC GUIDANCE WITH HIGHER THAN CLIMO POPS FOR TUE AND THEN SOMEWHAT LOWER THAN CLIMO...ESPECIALLY ACROSS THE MOUNTAINS FOR WED. BASICALLY CLIMO POPS RETURN FOR THE END OF THE WEEK. USED A BLEND OF HPC/GMOS FOR TEMPS WHICH ESSENTIALLY IS CLOSE TO CLIMO. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... AT KCLT...SHOWERS ARE BEGINNING TO DEVELOP OVER THE FOOTHILLS ABOUT 80 MI WEST OF THE AIRFIELD. WHILE CONVECTION IS EXPECTED TO BUILD OVER THE FOOTHILLS THE REST OF THE AFTN...IT WILL TAKE A WHILE FOR STORMS TO DEVELOP OUT ACROSS THE PIEDMONT. HOWEVER...MANY NUMERICAL MODELS ARE BULLISH ON DEVELOPING CONVECTION...AND I THINK THAT BY 22 UTC TSTMS ARE LIKELY TO DEVELOP IN PLACE OVER THE REGION. THE TEMPO GROUP FOR CONVECTION FROM 22-02 UTC STILL LOOKS GOOD FOR THIS REASON. THE MODEL GUIDANCE ALSO IS STRONGLY SUGGESTING THAT STRATUS WILL DEVELOP OVERNIGHT. WITH DEWPOINTS GETTING UP INTO THE LOW 70S AND EXPECTED WIDESPREAD UPSTREAM PRECIPITATION THIS LOOKS REASONABLE AND AN 800 FOOT CIG HAS BEEN INTRODUCED INTO THE TAF VERY LATE TONIGHT THROUGH MID MORNING ON SATURDAY. AND ELSEWHERE...SHRA/TSTMS ARE BEGINNING TO DEVELOP IN THE VCNTY OF THE KAVL AIRFIELD. VCTS HAS BEEN ADDED FOR THE NEXT FEW HOURS WITH PREVAILING THUNDER FROM LATE AFTN INTO THE EARLY EVENING AS IT LOOKS TO BE A STORMY EVENING IN THE MTNS AHEAD OF AN APPROACHING UPPER LOW. ONCE CONVECTION ENDS LATER TONIGHT LOW CLOUDS AND VALLEY FOG SHOULD DEVELOP. THE TIMING WILL DEPEND UPON HOW MUCH RAIN FALLS AT THE AIRFIELD AND HOW QUICKLY MID AND HIGH CLOUDS THIN. THE SAME APPLIES TO THE REST OF THE REGION...THOUGH IT WILL TAKE TSTMS A FEW HOURS YET TO BEGIN TO DEVELOP OUTSIDE THE MTNS. TEMPO OR PREVAILING GROUPS WILL PROBABLY BE NEEDED AT MOST AIRFIELDS...BUT CONFIDENCE ISN/T HIGH ENOUGH TO DO THAT YET OUTSIDE THE MTNS. WITH LOW 70S DEWPOINTS...15 KTS OF SLY LLVL FLOW AND MORE RAIN THIS EVENING...STRATUS IS A GOOD BET TONIGHT. BASED ON THE AMOUNT OF MIXING AND 800 FOOT DECK SEEMS REASONABLE. OUTLOOK...ISO/SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...NED NEAR TERM...JAT/MCAVOY SHORT TERM...LG LONG TERM...LG AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
238 PM EDT FRI AUG 3 2012 .SYNOPSIS... CIRCULATION AROUND HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL KEEP THE SOUTHERN APPALACHIAN REGION WARM AND HUMID THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO SLOWLY SWEEP ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA EARLY NEXT WEEK...POSSIBLY BECOMING STATIONARY AND LINGERING INTO LATE IN THE WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... CONVECTION HAS BEGUN TO DEVELOP OVER THE SOUTHWEST AND CENTRAL NC MTNS. LAYER RH VALUES ARE THE HIGHEST IN THIS PART OF THE FORECAST AREA...AND IT/S CLOSET TO THE APPROACHING SHORTWAVE TROUGH WHICH CURRENTLY EXTENDS FROM CENTRAL KY TO ERN TN. THE FEATURE ITSELF IS QUITE WEAK AND THE EFFECTIVE BULK SHEAR ACROSS THE REGION IS WELL UNDER 20 KTS. THEREFORE DIFFERENTIAL HEATING AND LLVL MASS CONVERGENCE SHOULD BE THE MAIN DRIVERS FOR CONVECTION THIS EVENING. THE LATEST HI-RES NUMERICAL MODEL RUNS ARE MORE VARIED THAN WHAT I SAW THIS MORNING. THE WRF-ARW AND THE HRRR BOTH DEVELOP CONVECTION OVER PARTS OF THE FA...BUT IT/S NOT LOOKING AS ORGANIZED AS EARLIER. THE 12 UTC 4KM SPC WRF ON THE OTHER HAND HAS A LARGE AREA OF CONVECTION OVER THE WESTERN UPSTATE AND NE GA THIS EVENING. THE 12 UTC NAM HAS STRONG LLVL CONVERGENCE THIS EVENING AND ALSO DEVELOPS INTENSE SLOW MOVING CONVECTION OVER THE UPSTATE. OVERALL...THE IDEA OF LIKELY POPS SLOWLY SPREADING FROM WEST TO EAST ACROSS THE FA THE REST OF THE AFN AND EVENING STILL LOOKS GOOD. DCAPE VALUES ARE WELL OVER 1000 J/KG ACROSS THE UPSTATE AND NE GA...AND PULSE SEVERE STORMS ARE A GOOD BET AGAIN THIS EVENING. PULSE SEVERE WON/T BE LIKELY OVER THE NC MTNS AND FOOTHILLS...BUT EVEN THOUGH CURRENT DCAPE VALUES AREN/T THAT GREAT...I STILL SUSPECT WE/LL SEE A FEW SEVERE STORMS ALONG THE I-77 URBAN CORRIDOR. VERY HEAVY RAIN IS ALSO POSSIBLE IS SPOTS AND ISOLATED FLASH FLOODING IS POSSIBLE. LATER TONIGHT WIDESPREAD LOW CLOUDS SHOULD DEVELOP ACROSS MOST OF THE FA. ON SATURDAY THE UPPER TROUGH WEAKENS QUICKLY AS THE ATLANTIC RIDGE STARTS TO BUILD BACK INTO THE REGION. THE WEAKENING OF THE TROUGH IS A LITTLE FASTER THAN WHAT WE/D BEEN EXPECTING. LAYER RH/S WILL REMAIN HIGH AND EVEN WITH VERY WEAK FORCING...THERE SHOULD BE PLENTY OF CONVECTION OVER THE HIGH TERRAIN AND A LITTLE LESS OUT ACROSS THE FOOTHILLS AND PIEDMONT. THE SEVERE AND FLOODING RISK DON/T LOOK AS GREAT TOMORROW. INTERESTINGLY...THE STRONGEST FORCING OF THE DAY COULD COME IN THE FORM OF THE SEA-BREEZE FRONT WHICH THE NAM BRINGS INTO THE SE ZONES EARLY IN THE EVENING. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 145 PM EDT...EXPECT SOME ONGOING SCATTERED CONVECTION SATURDAY EVENING TO WANE RATHER QUICKLY AS SUBTROPICAL RIDGE BUILDS WESTWARD INTO THE AREA SAT NIGHT. HENCE...THE SAT OVERNIGHT THROUGH SUNDAY MORNING IS EXPECTED TO BE TRANQUIL. ON SUNDAY AFTERNOON...UPSLOPE FLOW AND THE APPROACH OF A WEAK COLD FRONT FROM THE NW SHOULD TRIGGER SCATTERED TO NUMEROUS SHOWERS/THUDNERSTORMS ACROSS THE MOUNTAINS. ONLY ISOLATED TO WIDELY SCATTERED ACTIVITY IS EXPECTED ELSEWHERE. THE MODELS BRING THE FRONTAL BOUNDARY INTO THE MOUNTAINS SUNDAY NIGHT WHICH NECESSITATES MAINTAINING AT LEAST SCATTERED POPS THERE. ON MONDAY...THE FRONT IS FORECAST TO LAY OUT ACROSS THE WESTERN CAROLINAS INTO NE GA WHICH SHOULD BE A FOCAL POINT FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MAXIMUM TEMPERATURES ARE EXPECTED TO BE NEAR CLIMO WITH MIN TEMPERATURES ABOUT A CATEGORY ABOVE AVERAGE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 1 PM EDT FRIDAY...THE MEDIUM RANGE IS EXPECTED TO FEATURE SOME DEGREE OF BROAD UPPER TROFFING OVER THE EASTERN U.S. WITH PERHAPS SOME AMPLIFICATION IN THE TROUGH TOWARD THE END OF THE PERIOD. THE PERSISTENT TROUGH AND THE APPROACH OF A WEAK COLD FRONT WILL CONTINUE TO TRIGGER SHOWERS AND THUNDERSTORMS THROUGH TUE...WITH AN UPTICK DURING THE FAVORED AFTERNOON AND EVENING TIME PERIOD. THERE IS SOME DIVERGENCE IN THE GUIDANCE IN REGARD TO HOW FAR SOUTH THE AFOREMENTIONED FRONT GOES. THE ECM CAMP TAKES THE FRONTAL BOUNDARY JUST SOUTH OF THE AREA ON WED AND BRINGS SOMEWHAT DRYER INTO THE REGION FOR WED INTO THU. THIS WOULD PRODUCE A DECREASE IN SHOWER/THUNDERSTORM ACTIVITY FOR WED INTO THU. ON THE OTHER HAND... THE GFS HANGS UP THE BOUNDARY OVER THE AREA THROUGH THE PERIOD WITH A CONTINUATION OF ENHANCED SHOWER AND THUDNERSTORM ACTIVITY THROUGH THE END OF THE WEEK. HPC SIDED WITH THE ECM FRONTAL POSITION. WE GENERALLY STAYED CLOSE TO HPC GUIDANCE WITH HIGHER THAN CLIMO POPS FOR TUE AND THEN SOMEWHAT LOWER THAN CLIMO...ESPECIALLY ACROSS THE MOUNTAINS FOR WED. BASICALLY CLIMO POPS RETURN FOR THE END OF THE WEEK. USED A BLEND OF HPC/GMOS FOR TEMPS WHICH ESSENTIALLY IS CLOSE TO CLIMO. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... AT KCLT...SHOWERS ARE BEGINNING TO DEVELOP OVER THE FOOTHILLS ABOUT 80 MI WEST OF THE AIRFIELD. WHILE CONVECTION IS EXPECTED TO BUILD OVER THE FOOTHILLS THE REST OF THE AFTN...IT WILL TAKE A WHILE FOR STORMS TO DEVELOP OUT ACROSS THE PIEDMONT. HOWEVER...MANY NUMERICAL MODELS ARE BULLISH ON DEVELOPING CONVECTION...AND I THINK THAT BY 22 UTC TSTMS ARE LIKELY TO DEVELOP IN PLACE OVER THE REGION. THE TEMPO GROUP FOR CONVECTION FROM 22-02 UTC STILL LOOKS GOOD FOR THIS REASON. THE MODEL GUIDANCE ALSO IS STRONGLY SUGGESTING THAT STRATUS WILL DEVELOP OVERNIGHT. WITH DEWPOINTS GETTING UP INTO THE LOW 70S AND EXPECTED WIDESPREAD UPSTREAM PRECIPITATION THIS LOOKS REASONABLE AND AN 800 FOOT CIG HAS BEEN INTRODUCED INTO THE TAF VERY LATE TONIGHT THROUGH MID MORNING ON SATURDAY. AND ELSEWHERE...SHRA/TSTMS ARE BEGINNING TO DEVELOP IN THE VCNTY OF THE KAVL AIRFIELD. VCTS HAS BEEN ADDED FOR THE NEXT FEW HOURS WITH PREVAILING THUNDER FROM LATE AFTN INTO THE EARLY EVENING AS IT LOOKS TO BE A STORMY EVENING IN THE MTNS AHEAD OF AN APPROACHING UPPER LOW. ONCE CONVECTION ENDS LATER TONIGHT LOW CLOUDS AND VALLEY FOG SHOULD DEVELOP. THE TIMING WILL DEPEND UPON HOW MUCH RAIN FALLS AT THE AIRFIELD AND HOW QUICKLY MID AND HIGH CLOUDS THIN. THE SAME APPLIES TO THE REST OF THE REGION...THOUGH IT WILL TAKE TSTMS A FEW HOURS YET TO BEGIN TO DEVELOP OUTSIDE THE MTNS. TEMPO OR PREVAILING GROUPS WILL PROBABLY BE NEEDED AT MOST AIRFIELDS...BUT CONFIDENCE ISN/T HIGH ENOUGH TO DO THAT YET OUTSIDE THE MTNS. WITH LOW 70S DEWPOINTS...15 KTS OF SLY LLVL FLOW AND MORE RAIN THIS EVENING...STRATUS IS A GOOD BET TONIGHT. BASED ON THE AMOUNT OF MIXING AND 800 FOOT DECK SEEMS REASONABLE. OUTLOOK...ISO/SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...NED NEAR TERM...MCAVOY SHORT TERM...LG LONG TERM...LG AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
204 PM EDT FRI AUG 3 2012 .SYNOPSIS... CIRCULATION AROUND HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL KEEP THE SOUTHERN APPALACHIAN REGION WARM AND HUMID THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO SLOWLY SWEEP ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA EARLY NEXT WEEK...POSSIBLY BECOMING STATIONARY AND LINGERING INTO LATE IN THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1130 AM...THE LATEST NAM HAS A LARGE CONVECTIVE BULLSEYE OVER THE UPSTATE THIS EVENING. NORMALLY I WOULDN/T JUMP ON SUCH A FEATURE ON THE NAM. HOWEVER...THE LATEST RAP HAS A BULLSEYE IN DARN NEAR THE SAME PLACE. OUR TWO WORKSTATION WRF MODELS AND THE SPC HIGH RES WRF ALSO HAVE MORE CONCENTRATED AREAS OF CONVECTION ACROSS NE GA AND THE UPSTATE THIS EVENING. THE SRN NC PIEDMONT ALSO GETS INTO THE ACTION ON THE WRF-ARW. THE OLD GFS HAD A BULLSEYE FARTHER TO THE SW...OVER NE GA. THEY SEEM TO BE KEYING ON AN AREA OF LLVL CONVERGENCE THAT DEVELOPS THIS AFTN AS THE BNDRY LAYER FLOW IS SW OVER THE WRN UPSTATE AND NE GA...BUT BACKS TO THE SSE OVER THE I-77 CORRIDOR AHEAD OF THE APPROACHING MCV. CONSIDERING THAT SOMETHING QUITE SIMILAR HAPPENED LAST NIGHT WITH WEAKER FORCING...I/M GOING TO RAISE POPS TO LIKELY ACROSS THE I-85 CORRIDOR FOR THIS EVENING WITH THIS UPDATE. THE STORMS WILL BE SLOW MOVING AGAIN TODAY...RESULTING IN A THREAT OF LOCALIZED FLOODING. EAST OF THE MTNS THE MID-LEVELS STAY FAIRLY DRY INTO THE EVENING...YIELDING AN ISOLATED DAMAGING WIND THREAT AS WELL. AS OF 945 AM...ADDED A SMALL STRIPE OF LOW CHANCE POPS ACROSS THE CENTRAL UPSTATE...NORTHWARD INTO THE SRN NC FOOTHILLS AND WESTERN PIEDMONT. SCT SHRA HAVE DEVELOPED IN THIS AREA. BASED ON THE STRONG CAP ON THE 12 UTC GSO SOUNDING I/M SURE THESE SHRA ARE ELEVATED AND THEY SHOULD DISSIPATE ONCE MIXING INCREASES. HOWEVER...WE HAVE HAD REPORTS OF A COUPLE GOOD DOWNPOURS UNDER THEM SO IT/S WORTH AN UPDATE. THE REST OF THE GRIDS LOOK PRETTY GOOD. DECAYING MCS DEBRIS ARE WELL HANDLED...THOUGH I/VE ADDED A LITTLE CLOUD COVER ALONG THE ESCARPMENT WHEN A BAND OF STRATUS HAS DEVELOPED. AS OF 645 AM...NO MAJOR CHANGES WERE MADE WITH THIS UPDATE. MAINLY SKY COVER ADJUSTMENTS TO LINE UP WITH STRATUS DEVELOPMENT AND HIGH CLOUDS BLOWING IN FROM THE WEST. AS OF 230 AM...THE MAIN FCST CHALLENGE INVOLVES THE APPROACH OF AN MCV CURRENTLY OVER CENTRAL KY. THE NEAR TERM GUIDANCE...INCLUDING HI-RES MODELS ALL AGREE THAT THIS FEATURE SHUD SUPPORT SCATTERED TO NUMEROUS SHWRS AND TSTMS...POSSIBLY STARTING NOT LONG AFTER DAYBREAK IN THE WEST. THERE IS A LOT OF DEBRIS CLOUDINESS WITH THE MCS...AS CONVECTION IS STILL ONGOING ATTM. SO IT IS POSSIBLE THAT THE WRN ZONES MAY BE QUIET (DUE TO LACK OF INSOLATION)...WHILE THE EAST HAS MORE ACTIVITY. THE NAM IS A LITTLE SLOWER WITH THE MCV AND THE INITIATION OF STORMS...AND LIKE USUAL...HAS WARMER MAX TEMPS AND HIGHER SBCAPE THIS AFTN THAN THE GFS. FOR NOW...WENT WITH A MODEL BLEND...GIVEN UNCERTAINTY ON THE DISSIPATION OF THE MCS AND THINNING CLOUD COVER. THE INHERITED POPS LOOK PRETTY GOOD WHEN COMPARING TO THE MODEL CONSENSUS. FCST SNDGS SHOW MOISTENING MID LVLS AND VERY WEAK SHEAR. SO PROBABLY A CASE WHERE THERE WILL BE DECENT COVERAGE BUT ONLY A FEW PULSE SEVERE STORMS. MAX TEMPS WERE TWEAKED DOWN A DEG OR TWO IN SPOTS WITH LATEST BIAS-CORRECTED MOSGUIDE. TONIGHT...AS DEEP MOISTURE SETTLES INTO THE AREA AND AFOREMENTIONED MCV STALLS JUST TO OUR WEST...INDICATIONS ARE THAT ISOLD-SCT CONVECTION WILL LIKELY LINGER THRU MOST OF THE NIGHT. THE STEERING FLOW REMAINS WEAK AND PWATS APPROACH 2.00"...SO A SMALL HYDRO THREAT WILL EXIST. MIN TEMPS WILL BE TYPICAL OF LAST FEW DAYS (60S MTNS AND GENERALLY LWR 70S PIEDMONT). && .SHORT TERM /SATURDAY THROUGH MONDAY/... AS OF 145 PM EDT...EXPECT SOME ONGOING SCATTERED CONVECTION SATURDAY EVENING TO WANE RATHER QUICKLY AS SUBTROPICAL RIDGE BUILDS WESTWARD INTO THE AREA SAT NIGHT. HENCE...SAT OVERNIGHT THROUGH SUNDAY MORNING IS EXPECTED TO BE TRANQUIL. ON SUNDAY AFTERNOON...UPSLOPE FLOW AND THE APPROACH OF A WEAK COLD FRONT FROM THE NW SHOULD TRIGGER SCATTERED TO NUMEROUS SHOWERS/THUDNERSTORMS ACROSS THE MOUNTAINS. ONLY ISOLATED TO WIDELY SCATTERED ACTIVITY IS EXPECTED ELSEWHERE. THE MODELS BRING THE FRONTAL BOUNDARY INTO THE MOUNTAINS SUNDAY NIGHT WHICH NECESSITATES MAINTAINING AT LEAST SCATTERED POPS THERE. ON MONDAY...THE FRONT IS FORECAST TO LAY OUT ACROSS THE WESTERN CAROLINAS INTO NE GA WHICH SHOULD BE A FOCAL POINT FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MAXIMUM TEMPERATURES ARE EXPECTED TO BE NEAR CLIMO WITH MIN TEMPERATURES ABOUT A CATEGORY ABOVE AVERAGE. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 1 PM EDT FRIDAY...THE MEDIUM RANGE IS EXPECTED TO FEATURE SOME DEGREE OF BROAD UPPER TROFFING OVER THE EASTERN U.S. WITH PERHAPS SOME AMPLIFICATION IN THE TROUGH TOWARD THE END OF THE PERIOD. THE PERSISTENT TROUGH AND THE APPROACH OF A WEAK COLD FRONT WILL CONTINUE TO TRIGGER SHOWERS AND THUNDERSTORMS THROUGH TUE...WITH AN UPTICK DURING THE FAVORED AFTERNOON AND EVENING TIME PERIOD. THERE IS SOME DIVERGENCE IN THE GUIDANCE IN REGARD TO HOW FAR SOUTH THE AFOREMENTIONED FRONT GOES. THE ECM CAMP TAKES THE FRONTAL BOUNDARY JUST SOUTH OF THE AREA ON WED AND BRINGS SOMEWHAT DRYER INTO THE REGION FOR WED INTO THU. THIS WOULD PRODUCE A DECREASE IN SHOWER/THUNDERSTORM ACTIVITY FOR WED INTO THU. ON THE OTHER HAND... THE GFS HANGS UP THE BOUNDARY OVER THE AREA THROUGH THE PERIOD WITH A CONTINUATION OF ENHANCED SHOWER AND THUDNERSTORM ACTIVITY THROUGH THE END OF THE WEEK. HPC SIDED WITH THE ECM FRONTAL POSITION. WE GENERALLY STAYED CLOSE TO HPC GUIDANCE WITH HIGHER THAN CLIMO POPS FOR TUE AND THEN SOMEWHAT LOWER THAN CLIMO...ESPECIALLY ACROSS THE MOUNTAINS FOR WED. BASICALLY CLIMO POPS RETURN FOR THE END OF THE WEEK. USED A BLEND OF HPC/GMOS FOR TEMPS WHICH ESSENTIALLY IS CLOSE TO CLIMO. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... AT KCLT...SHOWERS ARE BEGINNING TO DEVELOP OVER THE FOOTHILLS ABOUT 80 MI WEST OF THE AIRFIELD. WHILE CONVECTION IS EXPECTED TO BUILD OVER THE FOOTHILLS THE REST OF THE AFTN...IT WILL TAKE A WHILE FOR STORMS TO DEVELOP OUT ACROSS THE PIEDMONT. HOWEVER...MANY NUMERICAL MODELS ARE BULLISH ON DEVELOPING CONVECTION...AND I THINK THAT BY 22 UTC TSTMS ARE LIKELY TO DEVELOP IN PLACE OVER THE REGION. THE TEMPO GROUP FOR CONVECTION FROM 22-02 UTC STILL LOOKS GOOD FOR THIS REASON. THE MODEL GUIDANCE ALSO IS STRONGLY SUGGESTING THAT STRATUS WILL DEVELOP OVERNIGHT. WITH DEWPOINTS GETTING UP INTO THE LOW 70S AND EXPECTED WIDESPREAD UPSTREAM PRECIPITATION THIS LOOKS REASONABLE AND AN 800 FOOT CIG HAS BEEN INTRODUCED INTO THE TAF VERY LATE TONIGHT THROUGH MID MORNING ON SATURDAY. AND ELSEWHERE...SHRA/TSTMS ARE BEGINNING TO DEVELOP IN THE VCNTY OF THE KAVL AIRFIELD. VCTS HAS BEEN ADDED FOR THE NEXT FEW HOURS WITH PREVAILING THUNDER FROM LATE AFTN INTO THE EARLY EVENING AS IT LOOKS TO BE A STORMY EVENING IN THE MTNS AHEAD OF AN APPROACHING UPPER LOW. ONCE CONVECTION ENDS LATER TONIGHT LOW CLOUDS AND VALLEY FOG SHOULD DEVELOP. THE TIMING WILL DEPEND UPON HOW MUCH RAIN FALLS AT THE AIRFIELD AND HOW QUICKLY MID AND HIGH CLOUDS THIN. THE SAME APPLIES TO THE REST OF THE REGION...THOUGH IT WILL TAKE TSTMS A FEW HOURS YET TO BEGIN TO DEVELOP OUTSIDE THE MTNS. TEMPO OR PREVAILING GROUPS WILL PROBABLY BE NEEDED AT MOST AIRFIELDS...BUT CONFIDENCE ISN/T HIGH ENOUGH TO DO THAT YET OUTSIDE THE MTNS. WITH LOW 70S DEWPOINTS...15 KTS OF SLY LLVL FLOW AND MORE RAIN THIS EVENING...STRATUS IS A GOOD BET TONIGHT. BASED ON THE AMOUNT OF MIXING AND 800 FOOT DECK SEEMS REASONABLE. OUTLOOK...ISO/SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...NED NEAR TERM...MCAVOY SHORT TERM...LG LONG TERM...LG AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
159 AM EDT FRI AUG 3 2012 .SYNOPSIS... WEAK HIGH PRESSURE WILL REMAIN ACROSS THE AREA THROUGH SATURDAY. THE HIGH PRESSURE WILL START TO BREAK DOWN FROM THE NORTHWEST ON SUNDAY...WITH A SURFACE COLD FRONT APPROACHING THE REGION MONDAY...AND LINGERING IN THE VICINITY THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TODAY/... 0530 UTC UPDATE...POPS HAVE BEEN REMOVED FOR THE REST OF TNGT PER TRENDS. MEANWHILE...A SLOW-MOVING MCS IS GRADUALLY DRIFTING SE ACRS CENTRAL KY. SOME OF THE OUTFLOW TO ITS EAST IS INITIATING SOME ISOLD CELLS. THE RAP AND GFS BOTH HAVE ASSOCIATED DPVA ARRIVING AROUND DAYBREAK ACRS THE NC MTNS. OTHERWISE...SKY/WIND GRIDS WERE UPDATED FOR 06Z TAFS. 0230 UTC UPDATE...POPS HAVE BEEN UPDATED TO ACCOUNT FOR CONVECTION IN NE GA...THE SC MOUNTAINS...AND SOUTH OF CHARLOTTE. SKY COVER WAS UPDATED FROM THE LATEST INFRARED SATELLITE IMAGERY. AT 907 PM EDT THURSDAY...A MEAN UPPER TROUGH REMAINED ALONG THE EASTERN SEABOARD...WHILE A WEAK SURFACE TROUGH EXTENDED ALONG THE APPALACHIANS. A MOIST UNSTABLE AIR MASS REMAINED OVER OUR AREA. AN OUTFLOW BOUNDARY THAT MOVED NORTHEAST FORM THE SC MIDLANDS HAS PROVIDED LIFT FOR CONVECTION TO FORM OVER THE UPPER SAVANNAH RIVER VALLEY AND THE CHARLOTTE METROPOLITAN AREA. THIS CONVECTION SHOWS LITTLE SIGN OF DECREASING OR MOVEMENT....AND IS EXPECTED OT LINGER INTO THE LATE NIGHT HOURS. IF PRECIPITATION RATES CAN PERSIST... HYDROLOGICAL PROBLEMS MAY DEVELOP. MINIMUM TEMPERATURES WILL BE BE SLIGHTLY ABOVE NORMAL. LATE IN THE DAY ON FRIDAY THE NAM AND GFS AGREE IN BRINGING AN MCV INTO THE MTNS...OR PERHAPS A LITTLE WEST OF THE REGION. IN FACT...THE OVERALL SYNOPTIC PATTERN SUPPORTS INCREASING TROUGHINESS OVER THE DEEP SOUTH BETWEEN TWO STRONG RIDGES...ONE OVER THE PLAINS AND ONE OVER THE WESTERN ATLANTIC. LAYER RH VALUES WILL BEGIN TO INCREASE ACROSS THE REGION LATE FRIDAY...RESULTING IN AN INCREASINGLY FRIENDLY ENVIRONMENT FOR CONVECTION. POPS HAVE BEEN RAISED INTO THE HIGH CHANCE TO LOW LIKELY RANGE OVER THE MTNS. THE PIEDMONT WILL REMAIN UNDER WEAK NVA THROUGH THE DAYLIGHT HOURS AND POPS HAVE BEEN KEPT LOWER IN THESE ZONES. EVEN WITH THE MOISTENING ATMOSPHERE...A FEW SEVERE STORMS ARE A GOOD BET IN THE AFTN...ESPECIALLY OVER THE MOUNTAINS AND FOOTHILLS. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... AS OF 230 PM THU...THE SHORT RANGE WILL FEATURE THE PASSAGE OF A WEAK WAVE ALOFT LATE FRIDAY NIGHT AND SATURDAY MORNING...WHICH MAY SERVE TO KEEP CONVECTION FIRING WELL INTO THE OVERNIGHT HOURS GIVEN THE RELATIVELY DEEP MOISTURE THAT SHOULD BE IN PLACE. SEE NOTHING THAT SHOULD DISCOURAGE DEEP CONVECTION FROM DEVELOPING WITH DAYTIME HEATING AGAIN ON SATURDAY...WITH STORMS BECOMING NUMEROUS ACROSS THE HIGHER TERRAIN LATE IN THE DAY. THE STORMS SHOULD PUSH OFF THE BLUE RIDGE IN THE EVENING AND EVENTUALLY DIE OFF LATE AT NIGHT...AS USUAL...SINCE THE UPPER WAVE SHOULD NOT BE AROUND TO HELP MAINTAIN. EXPECT MORE OF THE SAME ON SUNDAY AS THE SETUP DOES NOT REALLY CHANGE MUCH. PROFILES LOOK RELATIVELY MOIST AND TEMPS ARE RELATIVELY WARM AT MID LEVELS...WHICH MAY SERVE TO CUT BACK ON SEVERE STORM CHANCES. TEMPS WILL STAY NEAR CLIMO. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 2 AM EDT FRIDAY...THE MEDIUM RANGE FCST PICKS UP AT 12Z ON MONDAY WITH SOME DEGREE OF BROAD UPPER TROFFING LIKELY TO PERSIST OVER THE REGION THRU DAY 7. WITH THAT SAID...WE CAN EXPECT AN ACTIVE PERIOD TO PERSIST THRU NEXT WEEK WITH DIURNAL SH AND TS AND NEAR AVERAGE TEMPS. PREVIOUS DISCUSSION... LATEST GUIDANCE THROUGH THE MEDIUM RANGE FAVORS MAINTAINING A WEAKNESS AT 500 MB BETWEEN THE ATLANTIC SUBTROPICAL HIGH AND THE ANTICYCLONE OVER THE SOUTHWESTERN U.S.. THE GFS LEAVES AN AREA OF WEAK Q CONVERGENCE DRAPED ACROSS THE WESTERN CAROLINAS THROUGH WEDNESDAY AND KEEPS THE RIGHT ENTRANCE REGION OF THE UPPER JET OVERHEAD. AT THE SURFACE...AN OLD FRONTAL BOUNDARY SHOULD BE STALLED ACROSS THE OH VALLEY. A LIGHT S OR SW FLOW AT LOW LEVELS WILL MAINTAIN A SUPPLY OF MOISTURE. IN GENERAL...THIS WOULD APPEAR TO FAVOR AN ENHANCEMENT TO OUR USUAL DIURNAL THUNDERSTORM CHANCES...SO THAT IS ESSENTIALLY WHAT WILL BE PUT IN THE FCST. THERE MIGHT BE A SLIGHTLY IMPROVED CHANCE ON WEDNESDAY AS AN UPPER LEVEL FEATURE MOVES BY TO OUR NORTH. ANY OF THE DAYS THROUGH MID WEEK COULD SEE NUMEROUS STORMS...BUT FOR NOW WILL LIMIT THE CHANCE TO THE 40 PCT RANGE. THURSDAY SHOULD HAVE SLIGHTLY DIMINISHED CHANCES IN THE WAKE OF THE NORTHERN WAVE. TEMPS IN GENERAL WILL STAY NEAR CLIMATOLOGY WITH THE WARMEST DAY BEING THURSDAY. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AT KCLT...WITH CLEAR SKIES AND CALM WINDS...MAIN CONCERN WILL BE WHETHER ANY VSBY RESTRICTIONS DEVELOP ACRS THE AREA. GUIDANCE HAS BEEN TOO PESSIMISTIC WITH VSBYS LATELY. SO GOING WITH 6SM BR FOR NOW ARND DAYBREAK. EXPECTING NUMEROUS SHRA AND TSRA THIS AFTN...CONTINUING WELL INTO THE EVENING...AND PROB30 WILL BE CARRIED. WINDS WILL REMAIN SOUTHERLY...INCREASING TO NEAR 10 KNOTS THIS AFTERNOON. ELSEWHERE...GIVEN CLEARING SKIES...CALM/LGT WND AND RELATIVELY LOW DWPT DEPRESSIONS...I HAVE ADDED A TEMPO FOR MVFR VSBY AT ALL SITES...AND KEPT THE IFR TEMPO AT KAVL. AN ARRIVING UPPER SYSTEM WILL SUPPORT MORE WIDESPREAD CONVECTION TODAY...AND PROB30 WILL BE CARRIED AT ALL SITES. WINDS WILL FAVOR A SOUTHERLY COMPONENT. OUTLOOK...ISO/SCT AFTN-EVE TSTMS ACROSS THE AREA EACH DAY. MTN VLYS WILL SEE BEST CHANCE OF MORNING LOW CLOUDS/FOG. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...PAT NEAR TERM...ARK/JAT/MCAVOY SHORT TERM...PM LONG TERM...PM AVIATION...ARK
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1113 PM MDT THU AUG 2 2012 .AVIATION...06Z TAFS SCT TSTMS MOVING THROUGH CNTRL SD WILL MOVE OUT OF THE AREA BY 09Z. IFR CONDITIONS EXPECTED IN HEAVIER STORMS...OTHERWISE VFR CONDITIONS EXPECTED OVERNIGHT. STRONG COLD FRONT WILL MOVE THROUGH NERN WY AROUND 12Z AND WRN SD AROUND 15Z PRODUCING GUSTY NW WINDS OVER 30KTS IN SOME AREAS. && .PREV DISCUSSION... /ISSUED 829 PM MDT THU AUG 2 2012/ UPDATE...ONE COUNTY REMAINING IN THE WATCH AT 8 PM BUT WE WILL BE ABLE TO CANCEL THAT ONE WITHIN THE HOUR. THE SEVERE THUNDERSTORM IN EASTERN PENNINGTON COUNTY WILL MOVE INTO A MORE STABLE AIRMASS SHORTLY SO NOT SURE HOW MUCH LONGER IT CAN SUSTAIN THE STRONG UPDRAFT THAT KEPT IT GOING FOR OVER 160 MILES. HRRR HAS HAD A GOOD HANDLE ON THE LEADING EDGE OF THE SYSTEM ALL EVENING BUT KEEPS TOO MUCH PRECIP ONGOING BEHIND THE MAIN BAND. A BROAD SURFACE LOW OVER EASTERN WYOMING IS JUST STARTING TO SHIFT EASTWARD A BIT WITH SURFACE PRESSURE RISES OF 1 TO 1.5 MB/3HR SHOWING UP IN THE OBS OVER SOUTHEAST MONTANA AND NORTHEASTERN WYOMING THIS PAST HOUR. PREV DISCUSSION... /ISSUED 234 PM MDT THU AUG 2 2012/ DISCUSSION...UPPER LEVEL ANALYSIS HAS RIDGING ACROSS THE SOUTHERN AND SOUTHWESTERN PARTS OF THE UNITED STATES...WITH A WEAK SHORTWAVE RIDGE CROSSING THE NORTHERN PLAINS. VIGOROUS UPPER LOW IS CURRENTLY MOVING SOUTHEAST ALONG THE SPINE OF THE SOUTHERN CANADIAN ROCKIES. SHORTWAVE TROF IS UNDERCUTTING THE RIDGING ACROSS THE FORECAST AREA...PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS. A STRONG LINE OF STORMS HAVE DEVELOPED FROM NEAR GILLETTE INTO SOUTHEAST MONTANA. 20Z SURFACE ANALYSIS HAS HIGH PRESSURE OVER THE EASTERN DAKOTAS WITH LOW PRESSURE DEVELOPING OVER NORTHEAST WYOMING AND SOUTHEAST MONTANA. TEMPERATURES ARE IN THE 80S TO LOWER 90S WITH WINDS GENERALLY OUT OF THE SOUTH TO SOUTHEAST AT 15 TO 25 MPH. SURFACE LOW AND ASSOCIATED TROF OVER SOUTHEAST MONTANA AND NORTHEAST WYOMING WILL SLOWLY PUSH EAST THIS AFTERNOON AND EVENING...AND WILL BE FOCAL POINT FOR STRONG TO SEVERE CONVECTION. BEST INSTABILITY AND SHEAR RESIDE MAINLY FROM THE BLACK HILLS INTO NORTHWEST SOUTH DAKOTA...SO EXPECT STRONGEST STORMS TO CROSS THIS AREA. TEMP/TD SPREADS ARE FAIRLY LARGE...SO MAIN STORM THREAT WILL BE STRONG GUSTY WINDS...ALONG WITH SOME HAIL. SHOWERS AND STORMS WILL SHIFT EAST OF THE FORECAST AREA BY LATE THIS EVENING. FRIDAY...STRONG COLD FRONT WILL PUSH THROUGH OUR WESTERN ZONES IN THE MORNING AND THROUGH OUR EASTERN ZONES BY EARLY AFTERNOON. STRONG COLD ADVECTION AND PRESSURE RISES AROUND 3MB/3HR WILL SUPPORT GUSTY NORTHWEST WINDS...ESPECIALLY ON THE PLAINS OF NORTHWESTERN SD. CYCLONIC FLOW ALOFT...COMBINED WITH RESIDUAL INSTABILITY/MOISTURE WILL LEAD TO CHANCES FOR SHOWERS/TSTMS ACROSS OUR CWFA. TEMPS WILL BE WIDE RANGING...FROM THE 70S IN OUR WEST TO MID/UPPER 90S IN SOUTH CENTRAL SD AHEAD OF THE COLD PUSH. SATURDAY...DRY AND COOLER CONDITIONS EXPECTED...ALTHOUGH BREEZY/WINDY CONDITIONS WILL PREVAIL WITH STRONG NW FLOW ALOFT MIXING TOWARDS THE SURFACE DURING DAYTIME HEATING. EXTENDED...RIDGE WILL REBUILD OVER THE WESTERN CONUS...BRINGING A RETURN TO HOT AND DRY CONDITIONS EARLY IN THE WEEK. A VARIETY OF WEAK DISTURBANCES WILL PUSH THRU THE RIDGE DURING THE MIDDLE PART OF THE WEEK...BRINGING OCCASIONAL CHANCES FOR STORMS. ABOVE AVERAGE TEMPERATURES WILL CONTINUE THROUGH THE PERIOD. FIRE WEATHER... KEPT RED FLAG WARNING FOR THE PLAINS OF NORTHEASTERN WYOMING AS DRY THUNDERSTORMS MOVED ACROSS THE AREA THIS MORNING AND MORE STORMS ARE FIRING AT THIS TIME. WINDS HAVE FREQUENTLY GUSTED ABOVE 35 MPH EVEN THOUGH RH VALUES ARE STILL HOLDING AROUND 20 TO 25 PERCENT. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...WFO UNR LONG TERM....WFO UNR AVIATION...JOHNSON
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
922 PM CDT SAT AUG 4 2012 .DISCUSSION...WATER VAPOR SATELLITE/UPPER AIR PROFILER/WSR-88D VAD WIND PROFILES INDICATE A SHORTWAVE ACROSS SOUTHWEST MISSOURI THIS EVENING. THIS IS RESULTING IN NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS SOUTHWEST AND SOUTH CENTRAL MISSOURI. TEMPERATURES AS OF 8 PM CDT ARE IN THE 80S AT MOST LOCATIONS. SHOWER AND THUNDERSTORM CHANCES ALONG WITH THE POTENTIAL FOR STRONG TO PERHAPS SEVERE THUNDERSTORMS OVERNIGHT ARE THE PREDOMINANT CONCERNS IN THIS EVENING/S UPDATE. LATEST SHORT TERM RUC MODEL ALONG WITH CONVECTIVE TRENDS SUGGEST A POTENTIAL FOR THIS ACTIVITY TO BEGIN PROPAGATING EAST SOUTHEAST INTO AT LEAST THE NORTHWEST ONE THIRD OF THE MID SOUTH THIS EVENING. HAVE DISCOUNTED THE 00Z WRF THIS EVENING THUS FAR AS IT HAS EXPERIENCED SOME DIFFICULTY HANDLING THE CURRENT CONVECTIVE ACTIVITY OVER SOUTHERN MISSOURI. RADAR TRENDS INDICATE SOME WEAKENING HAS BEGUN TO OCCUR WITH THIS COMPLEX. AN ISOLATED STRONG TO PERHAPS SEVERE THUNDERSTORM MAY BE POSSIBLE ACROSS PORTIONS OF NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL IF IT BEGINS TO DROP INTO THE FORECAST AREA IN THE NEXT HOUR OR TWO. WILL UPDATE GRIDS TO ADJUST TIMING OF SHOWER/THUNDERSTORM CHANCES BASED ON LATEST TRENDS AND ADJUST ALL OTHER ELEMENTS AS NEEDED. UPDATED GRIDS WILL BE AVAILABLE SHORTLY. CJC && .PREV DISCUSSION... /ISSUED 637 PM CDT SAT AUG 4 2012/ UPDATE... DISCUSSION... PREV DISCUSSION... /ISSUED 333 PM CDT SAT AUG 4 2012/ DISCUSSION... FINALLY WILL SEE A PATTERN SHIFT OVER THE NEXT WEEK AS AN UPPER TROF MOVES OVER THE EASTERN UNITED STATES. EXPECT TWO COLD FRONTS TO MOVE THROUGH THE REGION WHICH SHOULD FINALLY BRING AN END TO THE HEAT WAVE. TONIGHT...A COLD FRONT THAT CURRENTLY STRETCHES FROM CHICAGO ILLINOIS TO ST JOSEPH MISSOURI WILL SINK SOUTH. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG THE FRONT THIS EVENING. SOME STORMS MAY BECOME SEVERE ALONG THE LINE. EXPECT THE LINE TO BEGIN MOVING INTO THE MIDSOUTH SHORTLY AFTER MIDNIGHT. THE LINE WILL LIKELY BE DYING BY THIS POINT BUT STILL CAN/T RULE OUT A FEW STRONG TO SEVERE STORMS. OTHERWISE...THIS EVENING SHOULD BE RELATIVELY QUIET WITH THE EXCEPTION OF A FEW STORMS ACROSS PORTIONS OF NORTHEAST MISSISSIPPI THAT ARE DEVELOPING IN RESPONSE TO A SHORTWAVE MOVING THROUGH THE REGION. HOWEVER THESE STORMS SHOULD BE SHORT-LIVED AS THE SHORTWAVE IS PUSHING EAST OF THE AREA. LOWS WILL BE IN THE MID TO UPPER 70S. SUNDAY...COLD FRONT MOVES INTO THE MIDSOUTH. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP IN RESPONSE TO THE FRONT INTERACTING WITH DAYTIME HEATING. EXPECT SOME STORMS TO BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. THE BIG QUESTION IS HOW MUCH ACTIVITY FROM THE OVERNIGHT THUNDERSTORMS WILL STILL BE AROUND AT 7 AM. THIS WILL PLAY A HUGE ROLE ON LATER THUNDERSTORM DEVELOPMENT AS WELL AS TEMPERATURES. CLOUD COVER FROM SOME SHOWERS THIS MORNING...REALLY PREVENTED DEVELOPMENT ACROSS WEST TENNESSEE. CLOUDS ALSO KEPT TEMPERATURES DOWN ACROSS WESTERN KENTUCKY. DEWPOINTS HAVE BEEN IN THE MID TO UPPER 70S AND EXPECT SIMILAR CONDITIONS TOMORROW. WILL FORECAST HIGHS IN THE LOWER TO MID 90S. THESE TEMPERATURES COMBINED WITH THE DEWPOINTS WILL PRODUCE HEAT INDICES ABOVE 105 DEGREES. BUT WITH SO MUCH UNCERTAINTY WILL HOLD OFF ON ISSUING A HEAT ADVISORY. WILL LET MIDNIGHT SHIFT SEE HOW OVERNIGHT CONVECTION EVOLVES TO MAKE FINAL CALL. SUNDAY NIGHT INTO MONDAY...FRONT WILL CONTINUE TO SINK SOUTH ACROSS THE CWA. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ACROSS NORTH MISSISSIPPI. MODELS ARE NOT AS QUICK TO PUSH DRIER AIR INTO THE CWA BEHIND THE FRONT. EXPECT LOWS TO STILL BE IN THE LOWER TO MID 70S WITH HIGHS ON MONDAY REMAINING IN THE LOWER TO MID 90S. MONDAY NIGHT THROUGH THURSDAY...SOME DRIER AIR DOES MOVE INTO THE MIDSOUTH. ALL MODELS INDICATING DIURNAL CONVECTION DEVELOPING EACH AFTERNOON MAINLY ACROSS SOUTHEASTERN PART OF THE CWA WHERE THE DEWPOINTS REMAIN HIGHER. LOWS WILL RANGE FROM THE UPPER 60S TO MID 70S WITH HIGHS IN THE LOWER TO MID 90S. THURSDAY NIGHT THROUGH FRIDAY NIGHT...A SECOND COLD FRONT WILL SINK SOUTH AS A BROAD UPPER TROF MOVES OVER THE EASTERN UNITED STATES. EXPECT CHANCES FOR SHOWERS AND THUNDERSTORMS TO EXPAND OVER THE ENTIRE CWA. HIGH TEMPERATURES ON FRIDAY MAY BE A TAD COOLER DUE TO CLOUD COVER AND THUNDERSTORMS. SATURDAY...SFC HIGH PRESSURE WILL MOVE INTO THE REGION. COOLER AND DRIER AIR WILL FILTER INTO THE REGION. EXPECT PLEASANT CONDITIONS AS A RESULT WITH HIGHS IN THE UPPER 80S FOR THE MOST PART. KRM && .AVIATION... 00Z TAF SET NO ADDITIONAL THUNDERSTORMS EXPECTED THIS AFTERNOON. WINDS WILL GENERALLY BE SSW AROUND 10 KTS THIS AFTN...DIMINISHING ONLY SLIGHTLY OVERNIGHT...BUT SHIFTING A BIT MORE SOUTHERLY. A COLD FRONT WILL APPROACH TOMORROW. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE THROUGHOUT THE DAY TOMORROW...CONTINUING INTO TOMORROW NIGHT. INCLUDED VCTS AT ALL SITES TOMORROW...WILL ADD PREVAILING TS WHEN STORMS DEVELOP AND THERE IS SOMETHING TO TIME BETTER. IFR VIS AND WIND WILL BE POSSIBLE AT LOCATIONS IMPACTED BY THUNDERSTORMS. && .PRELIMINARY POINT TEMPS/POPS... MEM 80 94 75 92 / 20 60 60 20 MKL 77 90 71 90 / 30 60 60 20 JBR 79 92 70 93 / 30 60 30 10 TUP 75 93 75 91 / 30 60 60 50 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1141 PM CDT THU AUG 2 2012 .UPDATE...FOR 06Z AVIATION FORECAST && .AVIATION... COMPLEX TO OUR NORTH NOT MAKING MUCH PROGRESS AND HAS SLOWED TO A CRAWL WITH MERGING CELLS OVER WESTERN KENTUCKY AS MOST SOUTHERN COMPLEX MERGES WITH THE NORTHERN ONE. NOT AN EASY FORECAST FOR THE OVERNIGHT BUT HERE WHAT I THINK WILL HAPPEN. SHORT WAVE UPSTREAM NOW OVER SOUTHERN ILLINOIS DOWN INTO SOUTHEAST MISSOURI WILL MOVE EAST IN THE OVERNIGHT AND INTO THE WESTERN SIDE OF THE TENNESSEE/OHIO VALLEYS. THE CAP THAT WE HAD EARLIER IS GONE. AS SHORT WAVE APPROACHES IT WILL SHARPEN AND THIS WILL INTENSIFY CONVECTION ON THE SOUTHWEST SIDE OF THE MCS ACROSS SOUTHERN ILLINOIS AND EXTEND DOWN THROUGH WESTERN KENTUCKY. AS CONVECTION DEVELOPS IT WILL DROP SOUTHEAST AND INTO MIDDLE TENNESSEE IN THE OVERNIGHT. I EXPECT STORMS IN THE BNA AREA BY 08Z-10Z TIME FRAME/EARLIER AT CKV. BOYD && .PREV DISCUSSION... /ISSUED 1002 PM CDT THU AUG 2 2012/ UPDATE...TERMINAL FORECASTS AVIATION... COMPLEX THAT HAD BEEN HEADED THIS WAY HAS SHOWN A MORE EASTWARD TREK TOWARD SOUTHWEST INDIANA/KENTUCKY. MODELS NOT HANDLING THIS VERY WELL BUT NAM MAY HAVE THE BEST HANDLE AT THE MOMENT. CAP CONTINUES TO HOLD OVER MIDDLE TENNESSEE BUT LATEST RUC FORECAST HAS IT WEAKENING TOWARD 06Z WITH TEMPS < +12 CELSIUS AT 700 MILLIBARS BY 04Z ACROSS THE MID STATE. THIS SHOULD ALLOW FOR SOME SOUTHWARD EXTENSION OF ACTIVITY DOWN INTO MIDDLE TENNESSEE AS WE GO TOWARD MIDNIGHT AND THROUGH THE OVERNIGHT HOURS. I COMPLETELY REWORKED TERMINAL FORECASTS FOR REMAINDER OF THE 24 HOUR PERIOD. CONFIDENCE IS LOW ON ANY PARTICULAR TIMING FOR STORMS SO WENT WITH VICINITY TSTMS. BOYD PREV DISCUSSION... /ISSUED 953 PM CDT THU AUG 2 2012/ UPDATE... FRONTAL BOUNDARY CONTINUES TO HANG JUST NORTH OF THE TN BORDER... WITH MID-LEVELS ACROSS THE FCST AREA CAPPED AT THIS POINT. COMPLEX IN WEST KY...SOUTH IL/IN WAS EXPECTED TO MOVE SOUTH BUT CURRENTLY IS PUSHING MORE EAST...WITH SOUTHERN FLANK STRUGGLING TO DEVELOP. CAP SLOWLY WEAKENS LATER THIS EVE BUT LATEST DATA SUGGESTING SCT STORMS WILL AFFECT MAINLY THE NORTH AND ESPECIALLY ALONG THE KY BORDER THRU 12Z...THEN BECOME MUCH MORE NUMEROUS ON FRIDAY. AT THIS TIME WILL RUN WITH CHANCE POPS...LEANING HIGHER NORTH...AND KEEP SOUTH GENERALLY UNCHANGED. MAY UPDATE AGAIN LATER SHOULD COMPLEX MAKE STRONG TURN SOUTH. PREV DISCUSSION... /ISSUED 754 PM CDT THU AUG 2 2012/ UPDATE...FOR 00Z AVIATION FORECAST AVIATION... GOOD CAP (+12 TO +13 DEGREES CELSIUS AT 700 MB) IN PLACE ACROSS NORTHERN MIDDLE TENNESSEE THIS EVENING HAS KEPT CONVECTION FROM DEVELOPING AROUND NASHVILLE. COMPLEX OVER SOUTHERN ILLINOIS HAS BEEN HEADED SOUTHEAST BUT IN THE LAST COUPLE OF PICS IT HAS SHOWN A LITTLE MORE EASTWARD COMPONENT. WILL HAVE TO KEEP TABS ON THIS AS MODELS BRING IT DOWN INTO WESTERN KY DURING THE EVENING AND INTO MIDDLE TN AROUND MIDNIGHT. LOOK FOR SOME LATE NIGHT FOG AT CROSSVILLE. BOYD PREV DISCUSSION... /ISSUED 351 PM CDT THU AUG 2 2012/ DISCUSSION... FORECAST REASONING WILL LEAN TOWARD A CONSENSUS MODEL SOLUTION COMPROMISE FOR THE FORECAST PERIOD UNLESS OTHERWISE NOTED. FORECAST QUANDARIES...IMPACTS OF POTENTIAL MCS TONIGHT AND ON FRI... POTENTIAL FOR SHWRS/TSTMS THRU MID WEEK NEXT WEEK...TEMPS. AS FOR TONIGHT...WILL BE WAITING CLOSE TO PRESS TIME PER REGIONAL RADAR TRENDS FOR FINAL DECISION...BUT EXPECT MVV ACROSS NRN MO PRESENTLY...ALONG WITH DEVELOPING EMBEDDED SHORTWAVE IN PREDOMINATELY NWLY FLOW ALOFT...TO RESULTING IN EVENTUAL AN MCS DEVELOPMENT EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING ACROSS CNTRL AND SERN MO...EVENTUALLY MOVING SEWD INTO AT LEAST WRN PORTIONS OF THE MID STATE DURING THE LATE EVENING HRS. MAY NEED TO BREAK OUT A LATE AFTERNOON GROUPING IN THE ZONE FORECAST PRODUCT TO EMPHASIZE ACTUAL TIMING IMPACTS. WILL CONTINUE TO GO WITH REASONING CLOSE TO MORNING FORECAST PACKAGE WITH MOST LOCATIONS W OF THE PLATEAU HAVING A CHANCE...TO EVEN LIKELY...SHWRS/TSTMS TOWARD DAYBREAK. WILL GO CLOSE TO CONSENSUS MODEL GUIDANCE ON LOWS...MAINLY IN THE MID 70S...BUT...WITH CLOUD COVERAGE POSSIBLY NOT AS PRONOUNCED ACROSS THE PLATEAU AND ONLY A SLIGHT CHANCE OF SHWRS/TSTMS PLATEAU LATE...WILL GO A COUPLE OF DEGREES COOLER THAN CONSENSUS GUIDANCE WITH LOWS MAINLY IN THE MID 60S. AS FOR FRI...WILL CONTINUE CLOSE TO PREVIOUS MORNING FORECAST REASONING CONCERNING FRI ALSO...WITH SHWRS/TSTMS LIKELY AREA WIDE DURING AT LEAST THE MORNING HRS. WITH SOME TIMING UNCERTAINTIES STILL IN PLAY THOUGH TO ACTUAL MOVEMENT AND EVENTUAL DISSIPATION ACROSS THE MID STATE...ALONG WITH THE CONTINUED PRESENCE OF A WEAK SFC BOUNDARY...EXPECT SOME CLRING POSSIBLY LATE...BUT WILL GO WITH HIGH CHANCE POPS FOR LOCATIONS GENERALLY W OF THE PLATEAU. WILL GO WITH A MODEL COMPROMISE ON HIGHS FOR FRI...WITH MOST LOCATIONS W OF THE PLATEAU IN THE UPPER 80S...MID 80S PLATEAU. AS FOR FRI NIGHT...EXPECT AN UNSETTLED WX PATTERN THRU FRI NIGHT WITH A CHANCE OF SHWRS/TSTMS THRU THE NIGHT...WITH LOWS MAINLY IN THE LOWER 70S...UPPER 60S TO 70 PLATEAU AS UPPER LEVEL FLOW BECOMES MORE ZONAL ORIENTATED IN NATURE...AND NOT MUCH POTENTIAL FOR OVERALL AIRMASS MOISTURE TO SIGNIFICANTLY DRY OUT AFTER AFTERNOON MCS INFLUENCES HAVE WEAKENED. AS FOR SAT...AS MENTIONED ALSO IN THIS MORNINGS DISCUSSION...AND MODELS CONSENSUS CONTINUING TO EMPHASIZE...ANOTHER SHORT WAVE IS EXPECTED TO SCOOT EASTWARD IN THE UPPER LEVEL FLOW...ACROSS KENTUCKY...ON SAT. HOWEVER...THIS DISTURBANCE CONTINUES TO LOOKS TO BE A LITTLE WEAKER AND...PERHAPS...A LITTLE FURTHER N THAN THE UPPER LEVEL FLOW PATTERN ACROSS THE MID STATE FRI NIGHT. HOWEVER... TSTMS TO OUR N SHOULD BE CLOSE ENOUGH TO SWING SOME OUTFLOW BOUNDARIES SWD INTO OUR OUR NRN COUNTIES. IN ADDITION...AND IT CONTINUES TO LOOK SO...ATM ACROSS THE MID STATE WILL REMAIN CHOCKED FULL OF MOISTURE...SUPPORTIVE OF AT LEAST SCT TSTMS DURING THE DAY ON SAT PER DIURNAL HEATING INFLUENCES KICKING IN...AND WILL CONTINUE WITH HIGH CHANCE POPS AREA-WIDE. WILL GO WITH HIGHS CLOSE TO CONSENSUS GUIDANCE VALUES AROUND 90...MID 80S PLATEAU. AS FOR SAT NIGHT...THE POTENTIAL FOR AN UPPER LEVEL EMBEDDED SHORTWAVE PASSAGE AROUND THE BASE OF A DEVELOPING UPPER LEVEL TROUGH ACROSS AT LEAST NRN PORTIONS OF THE MID STATE MAY BE POSSIBLE SAT NIGHT...AND THUS WILL CONTINUE WITH A CHANCE OF SHWRS/TSTMS THRU THE NIGHT TIME HRS. LOWS WILL MAINLY BE IN THE LOW TO MID 70S...AROUND 70 TO UPPER 60S PLATEAU. AS FOR THE REMAINDER OF THE FORECAST PERIOD...A CONTINUANCE OF THE OVERALL UNSETTLED WX PATTERN ON SUN AND MON...WITH A POTENTIAL DRYING TREND TOWARD THE MID PORTION OF NEXT WEEK IS THE GENERAL TREND FOR THE REMAINDER OF THE FORECAST PERIOD. OVERALL...IT LOOKS LIKE THE MID STATE WILL EITHER BE POSITIONED BETWEEN A SUMMERTIME COLD FRONT TO OUR N...AND A WARM MOIST AIRMASS TO OUR S...IF YOU LEAN MORE TOWARD THE EURO SOLUTION...OR THIS FRONT WILL PASS THRU THE MID STATE FROM OUR N SOMETIME LATE SUN NIGHT OR MON...AND THE AREA WILL BEGIN TO EXPERIENCE A DRYING AND WARMING TREND...IF YOU LEAN MORE TOWARD THE GFS SOLUTION. WITH SOME OVERALL UNCERTAINTY IN MIND...ESPECIALLY WHEN YOU FIGURE IN THE POSSIBILITY OF A POTENTIAL SHORTWAVE PASSAGE ACROSS THE NRN PORTIONS OF THE MID STATE ON SUN AIDING TO ADDITIONAL POTENTIAL FOR TSTM DEVELOPMENT...BELIEVE AT THIS TIME...THAT OVERALL... PREVIOUS FORECAST REASONING IS STILL VERY SOUND...AND OTHER THAN A TWEEK HERE AND THERE...WILL CONTINUE TO LEAN TOWARD IT ACCORDINGLY... I.E. MORE TOWARD THE GFS SOLUTION. THUS...WILL CONTINUE WITH THE MENTIONING OF LIKELY SHWRS/TSTMS DURING THE DAYLIGHT HOURS ON SUN... WITH A DRYING TREND BEGINNING TO ESTABLISH ITSELF BY MID WEEK. THIS WILL RESULT IN TEMPS NEAR OR SLIGHTLY ABOVE SEASONABLE NORMS...WITH HIGHS IN THE UPPER 80S TO LOWER 90S...MID 80S PLATEAU...AND LOWS AROUND 70...MID 60S PLATEAU. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
335 PM EDT FRI AUG 3 2012 .SYNOPSIS... SEVERAL UPPER LEVEL DISTURBANCES WILL MOVE EAST ACROSS OUR REGION TONIGHT INTO SATURDAY. ALOFT...A LARGE RIDGE OF HIGH PRESSURE COVERED TEXAS...THIS RIDGE FORECAST TO EXPAND OVER THE SOUTHEAST AND THE MIDDLE ATLANTIC THROUGH THE WEEKEND. A COLD FRONT WILL DROP SOUTH FROM THE GREAT LAKES AND THE OHIO VALLEY EARLY NEXT WEEK...THE RESULT OF AN AGGRESSIVE UPPER LEVEL TROUGH WHICH IS FORECAST TO MOVE THROUGH THE GREAT LAKES AND OHIO VALLEY REGION SUNDAY INTO MONDAY. && .NEAR TERM /THROUGH SATURDAY/... AS OF 305 PM EDT FRIDAY... COMPLICATED FORECAST WITH PLACEMENT OF CONVECTION THIS EVENING INTO TONIGHT. THE LOW CLOUDS WHICH LIFTED NORTH ACROSS THE REGION THIS MORNING ESPECIALLY ALONG THE EASTERN SLOPES OF BLUE RIDGE HAS SLOWED THE DEVELOPMENT OF THE THUNDERSTORMS THIS AFTERNOON AND HINDERED INSTABILITY. KFCX 88D SHOWED ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING AHEAD OF AREAS OF CONVECTION ACROSS EASTERN KENTUCKY. THIS CONVECTION IS ASSOCIATED WITH SHORTWAVE MOVING SLOWLY ESE. OUTFLOW AND LEFTOVER BOUNDARIES FROM THUNDERSTORMS WILL MOVE ACROSS OUR REGION THIS EVENING INTO TONIGHT. CONVECTION WHICH FIRES ALONG THE UPPER LEVEL DISTURBANCE ALONG THE CAROLINA COAST... MAY SEND AXIS OF DEEPER MOISTURE NORTHWARD INTO OUR SE CWA INITIATING LATE AFTERNOON AND EVE SHRA/TSRA. NAM...GFS...WRFARW-RNK AND HRRR PLACE THE HIGHEST POPS ACROSS SOUTHWEST PORTION OF CWA THIS AFTERNOON INTO TONIGHT. OVERALL...DEEP LAYER WINDS ACROSS THE MID ATLANTIC REGION REMAIN WEAK...MEAN WIND LESS THAN 10 KTS. ANY DEEP CONVECTION THAT DEVELOPS WILL BE SLOW MOVING WITH POTENTIAL OF HEAVY RAINS. TAPER OFF POPS WITH THE LOSS OF SOLAR HEATING TONIGHT BUT HOLD ON TO SOME ACTIVITY IN THE SOUTHWEST. LEANED LOW TEMPERATURES TONIGHT TOWARDS THE ADJMET WITH THE IDEA OF MORE CLOUDINESS KEEPING TEMPERATURES ELEVATED. ALSO ADD THE MENTION OF PATCHY FOG OVERNIGHT WHICH CAN BE SHAPED TO WHERE THUNDERSTORMS OCCUR. DEEPER MOISTURE WILL REMAIN IN PLACE ESPECIALLY OVER THE WEST SATURDAY. WEAKENING MID LEVEL WAVE AND OLD BOUNDARIES REMAINS ALONG THE MOUNTAINS SATURDAY AFTERNOON DURING MAX HEATING. THE COMBINATION OF W/NW FLOW ALOFT AND DECENT INSTABILITY WEST APPEARS TO BE A GOOD SETUP FOR MULTICELLULAR BANDS ACROSS THE MOUNTAINS...WITH SOME OF THIS ACTIVITY ABLE TO SPILL EAST OF THE BLUE RIDGE LATE. INCREASED POPS AND EXTENDED CHANCES OUT EAST TO THE PIEDMONT. SHAPED TIMING AND POPS CLOSE TO NAM. PLAYED HIGH CLOSER TO COOL MOS BECAUSE OF CLOUD COVER WITH READINGS FROM THE MID 70S IN THE MOUNTAINS TO AROUND 90 DEGREES IN THE SOUTHEAST. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 330 PM EDT FRIDAY... SCATTERED LINGERING SHOWERS AND STORMS LATE SATURDAY ARE LIKELY TO QUICKLY DISSIPATE BY LATE EVENING AS LITTLE IN THE WAY OF ORGANIZED FORCING IS EXPECTED IN GENERALLY SOUTHERLY FLOW. THE 12Z GFS PRODUCES SOME CONVECTIVELY INDUCED SHORT WAVES OVER TN/KY AND TRIES TO CONTINUE SOME ACTIVITY MOST OF THE NIGHT ACROSS THE WEST BUT FEEL THIS IS PROBABLY OVERDONE TO LARGE DEGREE...WHEREAS NAM HAS NOTHING ACROSS THE WEST BUT CONTINUES CONVECTION ACROSS THE FAR EAST WELL PAST MIDNIGHT IN ASSOC WITH A VERY WEAK LEE TROUGH. NOT SURE HOW MUCH TO TRUST EITHER SOLUTION...BUT WILL LEAN MORE TOWARD THE GFS NOTION OF KEEPING CHANCES GOING A LITTLE LONGER IN THE WEST...BUT WILL DROP POPS QUICKLY AFTER MIDNIGHT. SUNDAY APPEARS TO HAVE BETTER CHANCES...ESPECIALLY LATER IN THE DAY OUT AHEAD OF APPROACHING FRONTAL BOUNDARY COMING OUT OF OHIO VALLEY. SOME INCREASE IN SHEAR AND SLIGHTLY STEEPER LAPSE RATES SUGGEST A BETTER SEVERE POTENTIAL AS WELL...WITH MORE ORGANIZED CLUSTERS COMING OUT OF OF WV AHEAD OF FRONT. MAIN THREAT DURING THE DAY WOULD MAINLY BE IN THE WEST. EXACT TIMING IS IN QUESTION...INCLUDING WHETHER THERE WILL BE STORMS WELL OUT AHEAD OF FRONT DEVELOPING WITH MAX HEATING AND OVER HIGHER TERRAIN...OR DOES IT WAIT UNTIL FRONTAL BOUNDARY ACTUALLY ARRIVES WHICH WOULD BE MORE EVENING AND EVEN OVERNIGHT IN THE WEST. SEVERE CHANCES MUCH LESS EAST OF THE BLUE RIDGE GIVEN TIMING OF FRONT...BUT IF ANYTHING DEVELOPS WELL OUT AHEAD...A FEW OF THESE STORMS COULD DRIFT INTO THE PIEDMONT LATE IN THE DAY. IN ANY CASE...EXPECT AT LEAST MORE CLOUD COVER FROM UPSTREAM CONVECTION TO KEEP TEMPS DOWN A BIT IN THE WEST...SO WENT CLOSER TO COOLER MET GUIDANCE IN WEST...AND WARMER MAV IN EAST. BOUNDARY SLOWLY DRIFTS ACROSS THE FCST AREA SUNDAY NIGHT INTO MONDAY...AND MUCH BETTER CHANCE FOR LINGERING CONVECTION OR AT LEAST SHOWERS MOST OF THE NIGHT SUNDAY NIGHT...AND ANY REDEVELOPMENT OF DEEPER CONVECTION MONDAY WOULD BE ACROSS THE SOUTHEAST...AND DEPENDENT ON ANY SMALL DEGREE OF SFC HEATING...BUT SEVERE CHANCES SHOULD BE MUCH LOWER DUE TO LACK OF GOOD HEATING MONDAY. MONDAY MORNING LOWS SHOULD BE PRETTY MILD WITH MOSTLY CLOUDY AND EVEN ONGOING SHOWERS...AND MAV NUMBERS LOOK GOOD THERE WITH LOW TO MID 70S FOR MINS IN PIEDMONT AND UPPER 60S TO NEAR 70 WEST. SLIGHTLY COOLER TEMPS FOR MONDAY...ESPECIALLY BEHIND BOUNDARY IN WEST...BUT IN THE EAST WEVMAY NEED TO DROP TEMPS A LITTLE MORE IN THE EAST IF IT LOOKS LIKE CLOUDS AND SHOWERS WILL NOT GIVE WAY TO ANY SUNSHINE AT ALL DURING THE DAY MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 1230 PM EDT FRIDAY... THE WEATHER PATTERN THROUGH MUCH OF NEXT WEEK WILL BE INFLUENCED BY BOTH A STRONG RIDGE OF WARM HIGH PRESSURE OVER MUCH OF THE COUTH CENTRAL PORTIONS OF THE COUNTRY...AS WELL AS A DEVELOPING WEAK TROUGH ACROSS THE NORTHEAST WITH ASSOCIATED SLOW MOVING WEAK FRONTAL BOUNDARYS MOVING IN FROM THE NORTHWEST. THESE FEATURES WILL KEEP TEMPERATURES NEAR SEASONABLE READINGS THROUGH THE WEEK...WITH A CONTINUING CHANCE FOR SHOWERS AND THUNDERSTORMS ON MOST DAYS. MORE SPECIFICALLY...THE FRONTAL BOUNDARY SLOWLY MOVING ACROSS THE APPALACHIAN REGION ON MONDAY WILL LIKELY BE LINGERING ACROSS THE PIEDMONT INTO MONDAY NIGHT AND TUESDAY...BEFORE WASHING OUT ACROSS THE CAROLINAS. THERE ARE SIGNS IN SOME OF THE GUIDANCE OF A WEAK WAVE MOVING UP FROM THE SOUTHWEST...SO WHILE EXPECTING BETTER COVERAGE OF SHOWERS AND STORMS CLOSER TO THE FRONT IN THE EASTERN HALF OF THE FCST AREA TUESDAY...CAN ELIMINATE CHANCES FARTHER WEST GIVEN THIS POSSIBLE WAVE. WITH FAIRLY GOOD CLOUD COVER LIKELY...THIS COULD BE COOLEST DAY OF THE WEEK FOR SOME AREAS. WEDNESDAY WILL HAVE LESS OF A FOCUSING MECHANISM...BUT WITH WEAK TROUGH DEVELOPING OVERHEAD...AND MORE SUNSHINE PROBABLE...COULD RESULT IN STEEPER LAPSE RATES OVERALL...SO WORTH KEEPING CHC FOR SCATTERED AFTERNOON CONVECTION. PROBABLY BETTER CHANCES ACROSS THE SOUTHEAST...IF LINGERING CONVERGENCE WITH OLD BOUNDARY IS STILL PRESENT. BY THURS AND FRIDAY WILL HAVE TO RELY MORE ON DAYTIME HEATING AND LINGERING LOW LEVEL MSTR...BUT WITH WEAK TROUGH ALOFT AND NO PUSH OF DRIER AIR EVIDENT...FEEL ITS WORTH KEEPING LOW CHC POPS. ON FRIDAY THE INFLUENCE OF ANOTHER WEAK FRONT TO THE NORTH MAY BE ENOUGH TO PROVIDE SLIGHTLY BETTER CHANCES...BUT BY THIS TIME THERE IS ENOUGH DIFFERENCE IN MODEL GUIDANCE...WITH SOME HOLDING THIS FRONT OFF UNTIL SAT OR LATER...NOT TO PUT MUCH EMPHASIS ON MUCH OF A CHANGE BETWEEN THURS AND FRIDAY. WITH GENERALLY MORE SUN BY MID TO LATE WEEK ONCE THE FRONT FROM EARLY IN THE WEEK GOES BY AND WEAKENS...EXPECTING A VERY GRADUAL WARMING TREND BY LATE IN THE WEEK...WITH PIEDMONT HIGH TEMPS REACHING BACK INTO THE LOW TO MID 90S BY LATE IN THE WEEK. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... AS OF 130 PM EDT FRIDAY... LOW CLOUDS ARE MIXING OUT IN THE NRV AND ROA VALLEYS THIS AFTERNOON. AREA OF CONVECTION TO OUR WEST MOVING EAST TOWARD THE MOUNTAINS. MVFR CONDITIONS EXPECTED IN LOW CLOUDS AND CONVECTION THIS AFTERNOON INTO TONIGHT. MODELS EMPHASIZE A SHRTWV MOVING INTO FAR WRN VA/NC LATE IN THE DAY. THIS MAY PRODUCE SCT STORMS...BUT LOW CONFIDENCE ON EXACT TIME OF IMPACT FOR ANY OF TERMINALS. WILL MAINTAIN VCTS WITH THE BEST CHANCE EXPECTED AFTER 20Z/4PM. MEAN WINDS ALOFT ARE 10 KTS OR LESS...SO ANY SHRA/TSRA THAT DEVELOP WILL BE SLOW MOVING. DEEPER MOISTURE WILL OVERTAKE THE REGION THIS WEEKEND WITH GREATER COVERAGE OF SHOWERS AND STORMS...ESPCLY DURING THE AFTERNOON AND EVENING EACH DAY THROUGH MONDAY. LOCAL MVFR/IFR CONDITIONS WILL BE ASSOCIATED WITH THE MORE ORGANIZED STORMS. OUTSIDE OF THIS MAINLY DIURNALLY DRIVEN CONVECTION...THE ONLY OTHER FLIGHT WEATHER HAZARDS WOULD BE FROM OVERNIGHT VALLEY FOG. A COLD FRONT IS EXPECTED TO DROP SOUTHEAST OUT OF THE OHIO VALLEY MONDAY...CROSSING THE MID ATLANTIC REGION. WITH THE PASSAGE OF THIS FRONT...WINDS SHOULD BECOME NORTHERLY...WITH A DAY OR TWO OF DRY WEATHER AND VFR CONDITIONS FOLLOWING THE FRONTAL PASSAGE FOR MID WEEK. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...KK SHORT TERM...SK LONG TERM...SK AVIATION...KK/PM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
636 PM CDT SAT AUG 4 2012 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE. .SHORT TERM...TODAY THROUGH SUNDAY. STORMS FIRED ALONG BOUNDARY IN MANITOWOC AND WAUPACA COUNTIES THIS AFTN...AS THE MORNING RUNS OF THE HRRR MODEL INDICATED. CORRIDOR OF HIGH INSTABILITY FROM S WI INTO THE FAR E PART OF THE STATE AND CONVERGENCE ALONG BOUNDARIES ENOUGH TO INITIATE DEEP CONVECTION. MAIN LINE OF SHOWERS AND STORMS...HOWEVER...MOVING INTO THE WEST PART OF FORECAST AREA. THIS WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND EARLY EVENING PER LATEST RUN OF HRRR. BEST CHANCE OF SEVERE WILL BE SOUTH OF FORECAST AREA...BUT STILL A THREAT IN THE EAST-CENTRAL IN UNSTABLE AIRMASS AND INTERACTION OF LOW-LEVEL BOUNDARIES. UPPER TROF WILL QUICKLY SWING THROUGH TONIGHT. SMALL CHANCE FOR LINGERING SHOWERS BEHIND MAIN LINE LATER THIS EVENING. OTHERWISE...CLEARING SKIES ACROSS MUCH OF AREA. EXCEPTION IS IN THE FAR NORTH CLOSER TO THE UPPER LOW AND RESIDUAL MOISTURE. TEMPS TONIGHT AND SUNDAY ARE A BLEND OF MODELS...CLOSE TO PREVIOUS FORECAST. .LONG TERM...SUNDAY NIGHT THROUGH NEXT FRIDAY. MEAN LONGWAVE PATTERN FOR THE EXTENDED FORECAST PERIOD GENERALLY CHARACTERIZED BY A TROUGH OVER THE OHIO VALLEY AND RIDGE OVER THE INTERMOUNTAIN WEST. WESTERN GREAT LAKES REGION WILL RESIDE IN NORTHWESTERLY FLOW REGIME WITH AN OCCASIONAL EMBEDDED SHORTWAVE DISTURBANCES TRAVERSING THE AREA. TIMING AND INTENSITY OF EMBEDDED SHORTWAVE DISTURBANCES WITHIN THIS FLOW REGIME ARE TYPICALLY PROBLEMATIC...THUS FORECAST CONFIDENCE IN THIS REGARD IS LOW TO MEDIUM. EARLY IN THE WORK WEEK... DAYTIME TEMPERATURES WILL START OUT ABOVE NORMAL...THEN SLOWLY FALL BACK TO NEAR...OR PERHAPS SLIGHTLY BELOW NORMAL FOR EARLY AUGUST. SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD EASTWARD ACROSS THE FORECAST AREA SUNDAY NIGHT INTO MONDAY. WENT ON THE COOLER SIDE SIDE OF AVAILABLE GUIDANCE WITH RESPECT TO MIN TEMPERATURES SUNDAY NIGHT GIVEN CLEAR SKIES...LIGHT WINDS AND RATHER DRY DRY AIRMASS. MONDAY LOOKS LIKE A PLEASANT DAY WITH SUNNY SKIES...RELATIVELY LIGHT WINDS WITH DAYTIME HIGHS A FEW DEGREES ABOVE NORMAL. SHORTWAVE DISTURBANCE THEN FORECAST TO HEAD SOUTHEAST ACROSS SOUTHERN HUDSON BAY MONDAY NIGHT INTO EARLY TUESDAY. ASSOCIATED COLD FRONT WILL GET SHOVED SOUTHEAST TOWARD NORTHWEST WISCONSIN BY AROUND 06Z TUESDAY. APPEARS TO BE A PLUME OF HIGHER MID-LEVEL LAPSE RATES AND MODEST 850 WAA OUT AHEAD OF THIS SYSTEM. HOWEVER AVAILABLE MOISTURE IS SOMEWHAT LIMITED. THUS...HAVE MAINLY SMALL CHANCE POPS OVER NORTHWEST COUNTIES OVERNIGHT...THEN CARRY THESE SMALL POPS SOUTHEAST ACROSS THE AREA TUESDAY MORNING. MAJORITY OF GUIDANCE SUGGEST THAT FRONT WILL PASS SOUTHEAST OF THE FORECAST AREA BY ABOUT 18Z TUESDAY WITH CAA TO ENSUE DURING THE AFTERNOON. WEAK HIGH PRESSURE RETURNS TO THE AREA TUESDAY NIGHT INTO EARLY WEDNESDAY...WITH NEXT DISTURBANCE ALREADY APPROACHING THE NORTHERN MISSISSIPPI VALLEY BY WEDNESDAY MORNING. MODEL CONSENSUS SUGGESTS THIS SYSTEM WILL BE A BIT MORE POTENT AS IT TRAVERSES SOUTHEAST ACROSS THE FORECAST AREA THURSDAY. OPERATIONAL GFS AND ECMWF ARE A BIT FURTHER SOUTH WITH STRENGTHENING SURFACE LOW WHILE GEM A BIT FURTHER NORTH. BOTTOM LINE IS THAT IT LOOKS LIKE THERE WILL BE A PRETTY DECENT CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE DAY ON THURSDAY. BUMPED UP POPS FROM PREVIOUS FORECAST. SOME MODEL DIFFERENCES ON EVOLUTION OF UPPER TROUGH AND ASSOCIATED SURFACE LOW THURSDAY NIGHT INTO FRIDAY. SYSTEM DOES APPEARS TO SLOW DOWN SOMEWHAT AS IT DEEPENS JUST TO THE EAST OF THE FORECAST AREA...THUS PRECIPITATION COULD VERY WELL LINGER INTO FRIDAY ESPECIALLY OVER THE EASTERN HALF OF THE FORECAST AREA. CLOUDS...SCATTERED PRECIPITATION AND NORTHEASTERLY BOUNDARY LAYER FLOW ON FRIDAY WILL LIKELY HOLD TEMPERATURES MAINLY IN THE 70S. && .AVIATION...SHOWERS AND THUNDERSTORMS ALONG A COLD FRONT WILL EXIT EASTERN WISCONSIN EARLY THIS EVENING. PATCHY MVFR CIGS EXIST BEHIND THE FRONT SO WILL NEED TO SEE IF THEY EXPAND AS COOLING SETS IN THIS EVENING FOR POSSIBLE TAF AMENDMENTS. AREA OF BKN VFR STRATO-CU WILL ARRIVE OVER CENTRAL AND NORTH CENTRAL WISCONSIN LATE THIS EVENING AND INTO THE OVERNIGHT. INCLUDED MVFR OVER NORTH-CENTRAL AS THE LATEST MODELS INDICATE LOW CIGS OVER NORTHERN MINNESOTA WILL MAKE A RUN TOWARDS RHINELANDER LATE TONIGHT. THE BKN CIGS WILL SWING ACROSS THE REGION THROUGH ABOUT MID-MORNING TOMORROW BEFORE DRIER AIR ARRIVES FOR THE AFTERNOON AND DISSIPATES THE CLOUDS. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
244 PM CDT FRI AUG 3 2012 .SHORT TERM...TODAY THROUGH SATURDAY. IN THE NEAR-TERM...SC SLOWLY DISSIPATED DURING THE DAY THANKS TO EASTERLY LOW-LEVEL FLOW. AS CONVECTIVE TEMP IS MET...CU FIELD DEVELOPS...AS SEEN ON LATEST VIS SATELLITE IMAGERY. BOTH 03/15Z RUNS OF HRRR AND RAP INDICATE ISOLATED CONVECTION IN NE WI BETWEEN 3 AND 6 PM...NOT UNLIKE YESTERDAY`S EARLY EVENING ISOLATED EVENT. BUT PROBABILITY TOO LOW TO INCLUDE IN GRIDS AT THIS TIME. SHARP UPPER TROUGH WILL PRODUCE GOOD UPPER DIFFLUENCE ACROSS MINNESOTA TONIGHT. THAT COUPLED WITH A MODEST LOW LEVEL JET SHOULD RESULT IN CONVECTION THAT COULD DRIFT INTO OUR WESTERN COUNTIES TOWARD MORNING. BOTH THE 03/12Z NAM AND GFS HINT AT THIS. MINIMUM TEMPERATURES SHOULD BE HELD UP ABOVE NORMAL ONCE AGAIN BY INCREASING CLOUD COVER. THE UPPER TROUGH MOVES INTO WESTERN WISCONSIN LATE SATURDAY. WHILE DEBRIS FROM ANY LEFTOVER CONVECTION WILL HAVE TO BE DEALT WITH...AIRMASS SHOULD DESTABILIZE SUFFICIENTLY WITH PRESENCE OF UPPER TROF TO INCREASE THUNDERSTORM THREAT AFTER 18Z. INCREASING DEEP SHEAR AND INSTABILITY INDICATE THREAT FOR SEVERE STORMS...THOUGH BEST CHANCE WOULD BE ACROSS SE THIRD OF WI...PER SPC DAY 2 OUTLOOK. AS IS USUALLY THE CASE...SEVERE THREAT WILL LARGELY HINGE ON THE TIMING OF THE SYSTEM AND THE DEGREE OF INSTABILITY SATURDAY AFTERNOON. TEMPS ON SATURDAY SHOULD REACH NEAR 90 ACROSS THE FOX VALLEY WITH ANY AMOUNT OF SUNSHINE. TEMPS IN THE LOWER 80S ACROSS THE FAR N WITH MORE CLOUDS AND PRECIP TO START THE DAY. ALL-IN-ALL...PREVIOUS FORECAST WAS IN GOOD SHAPE SO ONLY MINOR TWEAKING WAS NEEDED. .LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY. MAIN FORECAST CONCERN WILL BE THE EXITING SYSTEM SUNDAY NIGHT AND CLOUDS/LINGERING PRECIP OVER THE NORTH SUNDAY MIDDAY. ...SATURDAY NIGHT AND SUNDAY... COLD FRONT SHOULD BE IN THE VICINITY OF THE FOX VALLEY AROUND 00Z SUNDAY. MODEL CONSENSUS HAS TRENDED TOWARDS THIS SLOWER SOLUTION...SO KEPT PRECIP IN THE CWA LONGER THAN THE PREVIOUS FORECAST. THE COLD FRONT SHOULD MOVE OUT WITH THE UPPER LEVEL SYSTEM AND CLEAR THE AREA BETWEEN 09-12Z SUNDAY. GFS/ECMWF HAVE BEEN THE SLOWEST AND KEEP PRECIP AROUND THE LONGEST...THEREFORE HAVE SHOWERS CONTINUING ON THE LAKESHORE UNTIL SUNDAY MORNING. AFTER THAT...MUCH OF THE AREA IS EXPECTED TO REMAIN DRY FOR SUNDAY. THE ONLY EXCEPTION BEING MODELS TRENDING TOWARDS AN AREA OF CLOUDS AND SHOWERS OVER NORTHERN WISCONSIN AROUND MIDDAY SUNDAY AS A WEAK JET STREAK SWINGS THROUGH ON THE BACK SIDE OF THE 500MB TROUGH. WITH MODERATELY UNSTABLE MIDLEVEL LAPSE RATES AROUND 7C AND THE GFS/GEM PUTTING PRECIP OVER THE NORTH SUNDAY MORNING THROUGH THE EARLY AFTERNOON...ADDED SLIGHT CHANCES OF SHOWERS OVER THIS AREA UNTIL MIDDAY PER MODEL TRENDS. SKIES WILL CLEAR OUT BY SUNDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE AREA. GUIDANCE HAS TRENDED COOLER SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH TEMPERATURES...SO BROUGHT MAX/MIN TEMPS DOWN A FEW DEGREES. WITH CLEARING SKIES AND CAA IN PLACE...MIN TEMPS COULD GET RELATIVELY COLD SUNDAY NIGHT. ...MONDAY THROUGH FRIDAY... HIGH PRESSURE HOLDS OVER WISCONSIN THROUGH MUCH OF THE PERIOD WITH WEAK IMPULSES MOVING THROUGH THE MEAN ZONAL FLOW. A COUPLE OF CHANCES FOR PRECIP IN THE EXTENDED...BEGINNING WITH MONDAY NIGHT INTO TUESDAY AS A WEAK COLD FRONT PUSHES SOUTHEAST THROUGH THE STATE. BETTER CHANCE LOOKS TO BE THURSDAY INTO FRIDAY AS A STRONGER SHORTWAVE SWINGS THROUGH NORTHERN WISCONSIN. TEMPERATURES SHOULD RETURN TO NEAR NORMAL OR SLIGHTLY ABOVE NORMAL LEVELS THROUGH NEXT WEEK. && .AVIATION...SC DISSIPATING SLOWER THAN EARLIER THOUGHT...BUT EDGES ARE THINNING AS WEAK MIXING DRAWS SOMEWHAT DRIER AIR DOWN TO SURFACE. VFR CONDITIONS WILL CONTINUE TO EXPAND. LIGHT EASTERLY WIND WILL BECOME SOUTHEAST THEN SOUTH BY 12Z. SOME MVFR VSBY WITH BR 09Z-12Z AT CENTRAL AND NE WI AIRPORTS. RHI MAY SEE CONVECTION AHEAD OF FRONT BY 09Z BUT WILL KEEP THUNDER OUT OF TAF FOR NOW. JKL && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ JKL/WOLF
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1158 PM CDT THU AUG 2 2012 .UPDATE... UPDATED FORECAST FOR LINE OF SCATTERED CONVECTION DEVELOPING IN 850 MB CONFLUENT AREA AHEAD OF SURFACE FRONT. MAINLY SPOTTY MODERATE SHOWERS BUT SOME ISOLATED THUNDER. LOW LEVEL CONVERGENCE AIDED BY LIFT FROM UPPER DIVERGENCE IN RRQ OF 300 MB SPEED MAX. EXPECT CONVECTION TO DIMINISH AS THIS ENHANCED LIFT MOVES OFF WITH SPEED MAX OVERNIGHT. && .AVIATION/06Z TAFS/... HAVE PUT VICINITY AT EACH SITE WITH TEMPO MVFR VSBYS TIMED WITH SOUTHEAST=MOVING LINE OF SCATTERED CONVECTION. EXPECT LINE TO BEGIN TO DIMINISH FROM WEST TO EAST AFTER 08Z AS UPPER SUPPORT SHIFTS TOT HE EAST. SURFACE COOL FRONT WILL DROP IN WITH NORTHEAST WINDS BRIEFLY COMING UP TO AROUND 10 KTS AT NEAR-LAKE SITES. HAVE MVFR VSBYS IN FOG POST-RAIN EXCEPT AT KMKE AND KENW DUE TO EXPECTED HIGHER SFC WIND WITH FRONTAL PASSAGE. && .PREV DISCUSSION... /ISSUED 354 PM CDT THU AUG 2 2012/ SHORT TERM... TONIGHT AND FRIDAY...FORECAST CONFIDENCE IS MEDIUM. AREA OF RAIN SHOWERS CONTINUES TO SHIFT EAST ACROSS THE NORTHERN COUNTIES OF THE FORECAST AREA. THIS AREA AIDED BY MODEST 850MB/700MB MOISTURE POOLING/CONVERGENCE AND LOW LEVEL FRONTOGENESIS RESPONSE. THIS AREA SHOULD CONTINUE TO SHIFT EASTWARD THROUGH THE REST OF THE AFTERNOON ACROSS THE NORTHEAST COUNTIES...ALONG WITH ASSOCIATED UPWARD VERTICAL MOTION. WEAK COLD FRONT FROM WEST CENTRAL TO NORTHEAST WISCONSIN IS EXPECTED TO SAG SOUTHWARD THROUGH THE AREA THIS EVENING...THEN TO THE SOUTH LATER TONIGHT. AREA OF WEAK TO MODEST 850MB CONFLUENCE ALSO SHIFTS SOUTH INTO THE AREA AND LINGERS THROUGH THE NIGHT. AREA FORECAST SOUNDINGS SHOWING CAP MIXING OUT ACROSS SOUTHERN PORTIONS OF THE AREA WHERE CLOUDS MOVED AWAY...WITH AROUND 500 J/KG MEAN LAYER CAPE. CLOUDIER AREAS WOULD HAVE LESS CAPE AND MORE CAPPING. CAPE BECOMES MORE ELEVATED TONIGHT AND WOULD HAVE TO BE REACHED BY ELEVATED PARCELS. HRRR MODEL SHOWING WIDELY SCATTERED CELLS AT BEST DEVELOPING LATE THIS AFTERNOON INTO THE EARLY EVENING. KEPT POPS FOR LATE THIS AFTERNOON INTO TONIGHT WITH THE ABOVE FORCING MECHANISMS MOVING IN. A GOOD PORTION OF THE AREA LIKELY WILL BE DRY. SCATTERED MID LEVEL CLOUDS EXPECTED TONIGHT INTO FRIDAY. DRIER AIR WORKS INTO THE AREA FRIDAY ON EASTERLY WINDS. KEPT DRY FORECAST GOING FOR FRIDAY WITH DECENT CAP ACROSS THE AREA. LOWS TONIGHT SHOULD FALL TO THE MID TO UPPER 60S...WITH ANOTHER VERY WARM DAY IN THE UPPER 80S TO LOWER 90S AWAY FROM THE LAKE. EAST WINDS KEEPS HIGHS COOLER NEAR LAKESHORE. FRIDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM TO HIGH A FAIRLY SHARP UPPER TROUGH WILL TRACK EWD FROM THE NRN HIGH PLAINS THROUGH THE GREAT LAKES DURING THIS PERIOD WITH AN ORGANIZED LOW PRESSURE AREA MOVING ALONG THE US/CANADIAN BORDER. THETAE ADVECTION WILL BOOST PWS TO NEARLY ONE INCH FOR SAT AFTERNOON AND EVENING AHEAD OF AND ALONG THE COLD FRONT ALONG WITH MODERATE INSTABILITY AND WIND SHEAR. THUNDERSTORMS WILL LIKELY DEVELOP SAT AFTERNOON OVER WRN WI AND THEN MOVE EWD THROUGH SAT EVENING. A SLIGHT RISK OF SEVERE THUNDERSTORMS IS FORECAST BY SPC AND LOOKS GOOD. COLD AND DRY ADVECTION WILL THEN PREVAIL ON SUNDAY WITH A PLEASANT DAY FOLLOWED BY HIGH PRESSURE THROUGH MON NT. LONG TERM... SRN WI WILL BE ON THE SRN PERIPHERY OF NW FLOW WITH ONLY A WEAK COOL FRONT TO POSSIBLY BE IN THE VICINITY OF SRN WI FROM TUE-WED. THUS ONLY SLIGHT CHANCE OF TSTORMS DURING THAT TIME. TEMPS WILL BE AT LEAST SLIGHTLY ABOVE NORMAL NEXT WEEK. AVIATION/00Z TAFS/... VFR CONDITIONS EXPECTED THROUGH FRIDAY ACROSS TAF SITES. CURRENT SHOWER ACTIVITY WILL CONTINUE TO REMAIN NORTH OF TAF SITES. EXPECT SCATTERED TO BROKEN MID LEVEL CLOUDS THROUGH THE LATE AFTERNOON. EAST/SOUTHEAST WINDS ARE EXPECTED TO LINGER AT MILWAUKEE AND REACH WAUKESHA BY 22Z. LIGHT WINDS ARE EXPECTED TO LINGER AT MADISON. WEAK COLD FRONT SLIDING SOUTH TOWARD THE AREA LATE THIS AFTERNOON...AND THROUGH THE AREA THIS EVENING. FRONT WOULD BRING MAINLY SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE EVENING...AND A SHOWER AFTER MIDNIGHT. HOWEVER...TOO MUCH UNCERTAINTY RIGHT NOW TO MENTION IN TAFS. LIGHT EAST TO NORTHEAST WINDS TONIGHT SHOULD REMAIN EASTERLY ON FRIDAY ACROSS TAF SITES...WITH FEW TO SCATTERED MID LEVEL CLOUDS. EASTERLY WINDS BRING DRIER AIR INTO THE AREA LATER TONIGHT AND FRIDAY...WITH QUIET WEATHER EXPECTED. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...REM TONIGHT/FRIDAY AND AVIATION/MARINE...WOOD FRIDAY NIGHT THROUGH THURSDAY...GEHRING
AREA FORECAST DISCUSSION
NWS ALBANY NY
425 AM EDT SUN AUG 5 2012 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND CROSS THE REGION TONIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED INTO OUR REGION IN THE WAKE OF THE COLD FRONT FOR MONDAY AND TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 420 AM EDT...PARTLY TO MOSTLY CLOUDY SKIES PREVAILED ACROSS THE FA WITH WARM AND MUGGY CONDITIONS. TEMPERATURES WERE GENERALLY IN THE UPPER 60S TO MID 70S. A VIGOROUS SHORT WAVE ACCOMPANIED BY A STRONG COLD FRONT WILL IMPACT OUR REGION DURING THIS PERIOD WITH THE POSSIBILITY OF A PRE-FRONTAL TROUGH CROSSING THE ALY FA LATE AFTERNOON INTO EARLY EVENING WHICH MAY ENHANCE THE CONVECTION. THERE ARE MANY INGREDIENTS IN PLACE FOR STRONG TO SEVERE THUNDERSTORMS AS WELL AS HEAVY RAIN WHICH COULD PRODUCE FLASH FLOODING ESPECIALLY WHERE CELLS TRAIN AND OR BACK BUILD. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR ALL OF EASTERN NEW YORK AND ADJACENT WESTERN NEW ENGLAND FROM 2 PM THIS AFTERNOON THROUGH EARLY MONDAY MORNING. THE TRAINING OF CELLS IS A DISTINCT POSSIBILITY AS THE COLD FRONT IS EXPECTED TO DROP FROM NORTHWEST TO SOUTHEAST AS THUNDERSTORMS MOVE FROM SOUTHWEST TO NORTHEAST ALONG AND AHEAD OF IT. PWATS RISE TO 2 TO NEARLY 2.5 INCHES THIS EVENING ALONG WITH A STRONG THETA E RIDGE H10-H8...AND K INDEX VALUES BTWN 35 AND 40. MLMUCAPES RISE UP TO 3000 J/KG THIS AFTERNOON WITH STRONG WIND FIELDS AS FA ENDS UP IN RIGHT ENTRANCE REGION OF A CYCLONICALLY CURVED 100+ KT JET ACRS ERN CANADA WHILE H8 WINDS INCREASE TO 35 TO 45 KTS AND H7 STEERING WINDS 35 TO 50 KTS FROM THE SOUTHWEST. FURTHER 0-3 KM HELICITY VALUES INCREASE TO 150 TO 250 M2/S2 LATER THIS AFTERNOON INTO THIS EVENING. THUS THE POTENTIAL FOR STRONG TO PERHAPS SEVERE WIND GUSTS EXIST WITH ANY STORMS AND SPC HAS THE ALY FA OUTLOOKED AS SLIGHT RISK IN THE DAY 1 OUTLOOK. THE THREAT OF LARGE HAIL IS CONSIDERABLY LESS AS WBZ HEIGHTS REMAIN ABOVE 12 KFT FOR MUCH OF THE PERIOD FROM THIS AFTERNOON THROUGH THIS EVENING. HAVE CHANCE POPS INCREASING TO LIKELY POPS FROM NORTHWEST TO SOUTHEAST DURING THE AFTERNOON INTO EARLY EVENING WITH LIKELY POPS ACROSS ENTIRE FA FOR MUCH OF THE EVENING WITH DECREASING POPS AFTER MIDNIGHT FROM NORTHWEST TO SOUTHEAST. EXPECT HIGHS TODAY GENERALLY IN THE LOW TO MID 80S WITH LOWS TONIGHT GENERALLY IN THE 60S TO LOWER 70S. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ANY LINGERING SHOWERS OR THUNDERSTORMS ACROSS THE SOUTHEAST PORTION OF THE FA ARE EXPECTED TO END EARLY MONDAY MORNING...OTHERWISE DRIER...MORE SEASONABLE AND MUCH LESS HUMID CONDITIONS ARE EXPECTED DURING THE SHORT TERM PERIOD WITH A GOOD DEAL OF SUNSHINE ON BOTH MONDAY AND TUESDAY AND MAINLY CLEAR SKIES MONDAY NIGHT AND TUESDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE REGION. EXPECT HIGHS ON MONDAY IN THE MID 70S TO MID 80S...LOWS MONDAY NIGHT IN THE MID 50S TO LOWER 60S...HIGHS ON TUESDAY IN THE UPPER 70S TO MID 80S AND LOWS TUESDAY NIGHT IN THE MID 50S TO MID 60S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... HAVE POPULATED THIS PORTION OF THE GRIDDED DATABASE WITH A 50/50 BLEND OF 18Z/04 HPC GUIDANCE AND 00Z/05 GMOS. WED-THU NT...A WEAKENING SHORTWAVE WILL APPROACH FROM THE WEST LATE WED...ALONG WITH AN ATTENDANT SURFACE BOUNDARY. FORCING ASSOCIATED WITH THESE FEATURES MAY TRIGGER ISOLATED SHOWERS WED AFTERNOON/EVENING ACROSS N/W AREAS...WHERE SLIGHT CHC POPS HAVE BEEN INDICATED. THIS BOUNDARY IS THEN EXPECTED TO STALL ACROSS THE REGION THU/THU NT. MARGINAL INSTABILITY...IN COMBINATION WITH WEAK FORCING FROM FRONTAL BOUNDARY MAY PRODUCE ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS ON THU...WHEN LOW CHC POPS ARE INDICATED. EXPECT TEMPS TO AVERAGE ABOVE SEASONAL LEVELS...ALONG WITH INCREASING HUMIDITY LEVELS DURING THIS TIME PERIOD...WITH DAYTIME MAXES REACHING THE MID TO UPPER 80S IN VALLEYS...AND UPPER 70S TO LOWER 80S ACROSS HIGHER ELEVATIONS. OVERNIGHT MINS SHOULD FALL INTO THE LOWER/MID 60S IN VALLEYS...AND 55-60 ACROSS HIGHER ELEVATIONS. FRI-SAT...CONFIDENCE INCREASING THAT A RATHER UNSETTLED PERIOD SHOULD OCCUR...AS AN AMPLIFYING SHORTWAVE SLOWLY APPROACHES FROM THE GREAT LAKES REGION...AND POTENTIALLY CLOSES OFF UPON APPROACHING FROM THE WEST/SOUTHWEST. AT THE SURFACE...A WAVE...OR SERIES OF WAVES ARE EXPECTED TO DEVELOP ALONG THE AFOREMENTIONED STALLED FRONTAL BOUNDARY ACROSS THE REGION. THERE REMAINS SOME UNCERTAINTY IN THE EXACT PLACEMENT AND DETAILS OF THE DEVELOPMENT OF ANY SFC WAVE...AND MOVEMENT OF FRONTAL SYSTEMS AT THIS TIME RANGE...BUT AT THE VERY LEAST...IT APPEARS THAT SEVERAL ROUNDS OF SHOWERS/THUNDERSTORMS WILL BE POSSIBLE DURING THIS TIME PERIOD. AND...DEPENDING ON HOW FAR SOUTH ANY SFC WAVE TRACKS...A PORTION OF THE REGION COULD EVEN RECEIVE A STEADY...BENEFICIAL RAINFALL. HAVE INCLUDED HIGH CHC POPS AT THIS TIME. GIVEN THE UNCERTAINTY IN FRONTAL BOUNDARIES WITH THIS SYSTEM...TEMPERATURES REMAIN TRICKY...AS A MORE SOUTHERN TRACK WITH THE LOW WOULD FAVOR NEAR OR EVEN BELOW NORMAL DAYTIME MAXES. FOR NOW...HAVE SIDED WITH THE AFOREMENTIONED 50/50 BLEND OF HPC GUIDANCE AND GMOS...WITH DAYTIME MAXES IN THE LOWER 80S IN VALLEYS...AND 70S ELSEWHERE...AND OVERNIGHT MINS MAINLY IN THE 60S AS CLOUDS AND HIGHER HUMIDITY LEVELS KEEP NIGHTTIME TEMPS RELATIVELY WARM. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... A COLD FRONT APPROACHING FROM THE WEST WILL TRIGGER NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THE FIRST HALF OF TONIGHT. VFR CONDITIONS WILL GRADUALLY BECOME MVFR...MAINLY FOR CIGS...AS LOW STRATUS ADVECTS AND/OR DEVELOPS NORTHWARD THROUGH SUNRISE. TRICKY CALL ON WHETHER IT REMAINS LOW MVFR...OR IFR. AT THIS TIME...FOLLOWED CLOSE TO THE HRRR OUTPUT...WHICH IMPLIES MAINLY MVFR CIGS INITIALLY...WITH A CHANCE FOR IFR AFTER 09Z/SUN AT ALL TAF SITES. HOWEVER...LOCAL DOWNSLOPING WITH A S/SE FLOW MAY PREVENT CIGS FROM CRASHING TO IFR AT KPSF AND KPOU. HAVE INDICATED ONLY BRIEF PERIODS OF IFR TOWARD 12Z/SUN AT THESE LOCATIONS. THIS STRATUS MAY BEGIN TO BREAK UP SUNDAY MORNING AS THE FRONTAL BOUNDARY BEGINS TO APPROACH...AND THE FLOW BECOMES MORE SW. CONDITIONS SHOULD GO BACK TO VFR AT ALL SITES BY THE LATE MORNING HOURS. SOME SHOWERS AND TSTMS ARE POSSIBLE BY LATE IN THE DAY INTO SUNDAY NIGHT AS THE FRONT CROSSES THE REGION. HAVE INDICATED A VCTS FOR ALL TAF SITES AFTER 18Z-20Z/SUN...AS THUNDERSTORMS SHOULD BECOME RATHER NUMEROUS LATER THIS AFTERNOON...WELL INTO THIS EVENING. IT IS LIKELY THAT SEVERAL DISCRETE ROUNDS OF THUNDERSTORMS OCCUR DURING THIS TIME PERIOD...WITH SOME BREAKS IN BETWEEN. THE THREAT FOR THUNDERSTORMS WILL GRADUALLY DECREASE TOWARD AND ESP AFTER 06Z/MON...FIRST AT KGFL AND KALB...AND LAST AT KPSF AND KPOU. AREAS OF MVFR/IFR FOG MAY OCCUR TOWARD AND AFTER 06Z/MON AT ALL TAF SITES. SOUTH/SOUTHEAST WINDS WILL PERSIST THROUGH DAYBREAK AT KALB AND 8-12 KT...WITH SOME GUSTS POSSIBLY REACHING 15-20 KT. ELSEWHERE...WINDS SHOULD BECOME LIGHT/VARIABLE THROUGH DAYBREAK. WINDS WILL THEN INCREASE FROM THE SOUTH BY MID MORNING AT 8-12 KT...EXCEPT STRONGER...AT 10-15 KT AT KALB...WITH SOME GUSTS OF 20-25 KT POSSIBLE. SOUTH WINDS WILL GRADUALLY VEER INTO THE SW TO W LATER THIS EVENING...AT 5-10 KT. WINDS WILL BE MUCH STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR ANY THUNDERSTORMS. OUTLOOK... SUN NIGHT...MVFR/IFR. SHRA/TSRA LIKELY EARLY. MON...VFR. SLIGHT CHC -SHRA EAST OF THE HUDSON RIVER EARLY IN THE MORNING. TUE...VFR. NO SIG WX. WED...VFR. SLIGHT CHC -SHRA/-TSRA. THU...VFR. CHC OF -SHRA/-TSRA. && .FIRE WEATHER... WET FLAG CONDITIONS ARE EXPECTED FROM THIS AFTERNOON THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND CROSS THE REGION TONIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED INTO OUR REGION IN THE WAKE OF THE COLD FRONT FOR MONDAY AND TUESDAY. && .HYDROLOGY... A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF EASTERN NEW YORK AND ADJACENT WESTERN NEW ENGLAND FROM 2 PM THIS AFTERNOON THROUGH EARLY MONDAY MORNING. A STRONG COLD FRONT WILL APPROACH OUR REGION FROM THE NORTHWEST TODAY AND CROSS THE AREA TONIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. INCREASING PRECIPITABLE WATER VALUES ARE EXPECTED THE FIRST HALF OF TONIGHT RISING TO 2 TO PERHAPS AS HIGH AS 2.5 INCHES AHEAD OF THE STRONG COLD FRONT. EXPECT THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR FROM LATER THIS AFTERNOON THROUGH LATE TONIGHT WITH TORRENTIAL DOWNPOURS OCCURRING IN SOME AREAS. IN ADDITION THUNDERSTORMS MAY TRAIN AND OR BACK BUILD ACROSS THE SAME AREA INCREASING THE POSSIBILITY OF FLASH FLOODING. RAINFALL AMOUNTS IN MANY AREAS WILL BE 1 TO 3 INCHES WITH 3 TO 6 INCHES OF RAIN POSSIBLE IN AREAS WHERE THUNDERSTORMS TRAIN AND OR BACK BUILD. WHILE RIVER FLOODING IS GENERALLY NOT EXPECTED...SIGNIFICANT WITHIN BANK RISES ARE EXPECTED ON SOME RIVERS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR CTZ001-013. NY...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR NYZ032-033-038>043-047>054-058>061-063>066- 082>084. MA...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR MAZ001-025. VT...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR VTZ013>015. && $$ SYNOPSIS...IAA/FRUGIS/11 NEAR TERM...11 SHORT TERM...11 LONG TERM...KL AVIATION...FRUGIS/KL FIRE WEATHER...11 HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
144 AM EDT SUN AUG 5 2012 .SYNOPSIS... TONIGHT WILL BE WARM AND MUGGY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST SUNDAY AND CROSS THE REGION AT NIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A COOLER...MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED IN THE WAKE OF THE COLD FRONT FOR EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 120 AM EDT...MAINLY CLEAR SKIES HAVE GIVEN WAY TO PARTLY TO MOSTLY CLOUDY SKIES ACRS THE SRN HLF OF THE FA AS LOW STRATUS HAS STARTED TO LIFT NORTHWARD FROM SOUTHEAST NY AND SW NEW ENGLAND. EXPECT THIS TREND TO CONTINUE WITH SKIES BECOMING PARTLY TO MOSTLY CLOUDY LATER TONIGHT ACRS THE ENTIRE FA. THERE MAY BE SOME RADIATIONAL FOG IN SPOTS...BUT IT WILL DEPEND ON HOW QUICKLY THE STRATUS SPREADS INTO THE REGION. IT WILL REMAIN MUGGY OVERNIGHT...AND MIN TEMPS WILL BE IN THE 70S IN THE CAPITAL REGION OVERNIGHT...WITH MID TO UPPER 60S ELSEWHERE. AN MCS IS CURRENTLY ONGOING ACROSS OHIO. THERE HAS BEEN PLENTY OF CG LTG ACTIVITY WITH THIS STRONG BATCH OF CONVECTION AHEAD OF A POTENT COLD FRONT. THE 00 UTC NAM AND LATEST 01 UTC 3KM HRRR DO NOT HAVE A GOOD HANDLE ON THIS CURRENT ONGOING ACTIVITY. CONSIDERING THAT THE UPPER TROUGH APPEARS TO BE IN THE PROCESS OF SHEARING OUT...WE DON/T ANTICIPATE THIS ACTIVITY MAKING IT INTO OUR AREA BY THE LATE NIGHT HOURS...BUT WE WILL CONTINUE TO MONITOR RADAR TRENDS. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... THE STORM PREDICTION CENTER CONTINUES TO HAVE THE FORECAST AREA IN A SLIGHT RISK FOR THUNDERSTORMS IN THE DAY 2 OUTLOOK. HOWEVER TO NOTE THE AREA OUTLINED BY THE 30 PERCENT COMBINED PROBABILISTIC OUTLOOK FOR SEVERE WEATHER HAS BEEN DECREASED. ALL BUT THE NORTHWEST CORNER OF OUR FORECAST AREA IS NOW UNDER THE 15 PERCENT PROBABILISTIC OUTLOOK. THE MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH THE TIMING OF THE COLD FRONT WHICH WILL NOT CROSS THE AREA UNTIL SUNDAY NIGHT. THE UPPER TROUGH AXIS WILL MOVE ACROSS THE GREAT LAKES REGION DURING THE DAYTIME AND ACROSS EASTERN CANADA SUNDAY NIGHT. NOT MUCH IN THE WAY OF HEIGHT FALLS WILL OCCUR ACROSS OUR REGION. THE BEST DYNAMICS WILL REMAINS JUST TO OUR NORTH AND WEST. MID LEVEL LAPSE RATES WILL BE RATHER WEAK AROUND 5.5 C/KM. MODELS INDICATE MARGINAL INSTABILITY. 500 MB TEMPERATURES WILL WARM TO AROUND -6C WHICH WILL LIMIT DESTABILIZATION. THE 0-6KM BULK SHEAR OF 20 TO 25 KNOTS WILL INCREASE TO 30 TO 40 KNOTS SUNDAY NIGHT. HAVE POPS INCREASING TO LIKELY DURING THE AFTERNOON INTO THE EVENING HOURS. VALUES ARE STILLED MODELED TO INCREASE TO 2-2.25 INCHES ACROSS THE AREA AHEAD OF THE APPROACHING COLD FRONT...SO VERY HEAVY/TORRENTIAL DOWNPOURS WILL BE EXPECTED WITH SOME STORMS. THE HEAVY RAINS COULD RESULT IN LOCALIZED FLOODING OF LOW LYING AND POOR DRAINAGE AREAS. AND IF TRAINING OF THUNDERSTORMS OCCURS THEN ISOLATED FLASH FLOODING WOULD BE POSSIBLE. WILL KEEP THIS HIGHLIGHTED IN OUR HAZARDOUS WEATHER OUTLOOK AND KEEP HEAVY RAINFALL MENTIONED IN FORECAST. THE HOT AND HUMID AIRMASS WILL BE REPLACED BY A COOLER...MORE SEASONABLE AND DRIER AIRMASS TO START THE WEEK. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HPC GUIDANCE. ANOTHER INCLEMENT SUMMER PATTERN SETS UP WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY FROM THURSDAY THROUGH THE END OF THE WEEK. LOW PRESSURE OFF THE CANADIAN ROCKIES WILL TRACK FROM THE NORTHERN PLAINS THROUGH THE GREAT LAKES REGION THROUGH SATURDAY. A COLD FRONT AHEAD OF THE LOW PRESSING SOUTH ACROSS THE FORECAST AREA ON THURSDAY BEGINS THE PATTERN. JUST AHEAD OF THE LOW ON SATURDAY IT RETURNS AS A WARM FRONT...WITH THE MAIN COLD FRONT SLIDING EAST ACROSS THE AREA EARLY SATURDAY. THE TIMING OF THIS LATTER FRONTAL PASSAGE WILL DECIDE THE EXTEND OF ANY REMAINING THUNDERSTORM ACTIVITY ON SATURDAY AS HIGH PRESSURE WILL BE MAKING A RETURN. HIGH TEMPERATURES WEDNESDAY AND THURSDAY WILL RANGE MAINLY FROM AROUND 80 DEGREES IN THE HIGH ELEVATIONS...TO AROUND 90 IN THE MOHAWK AND HUDSON VALLEYS. HIGHS FRIDAY WILL BE FROM THE MID 70S TO MID 80S...WITH SLIGHTLY COOLER READINGS FOR SATURDAY. LOWS WILL START OFF TUESDAY NIGHT FROM MAINLY THE UPPER 50S TO MID 60S. THE NIGHT WILL BECOMING INCREASINGLY MILDER...HOWEVER...WITH LOWS FRIDAY NIGHT MAINLY FROM THE MID 60S TO AROUND 70 DEGREES. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... A COLD FRONT APPROACHING FROM THE WEST WILL TRIGGER NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THE FIRST HALF OF TONIGHT. VFR CONDITIONS WILL GRADUALLY BECOME MVFR...MAINLY FOR CIGS...AS LOW STRATUS ADVECTS AND/OR DEVELOPS NORTHWARD THROUGH SUNRISE. TRICKY CALL ON WHETHER IT REMAINS LOW MVFR...OR IFR. AT THIS TIME...FOLLOWED CLOSE TO THE HRRR OUTPUT...WHICH IMPLIES MAINLY MVFR CIGS INITIALLY...WITH A CHANCE FOR IFR AFTER 09Z/SUN AT ALL TAF SITES. HOWEVER...LOCAL DOWNSLOPING WITH A S/SE FLOW MAY PREVENT CIGS FROM CRASHING TO IFR AT KPSF AND KPOU. HAVE INDICATED ONLY BRIEF PERIODS OF IFR TOWARD 12Z/SUN AT THESE LOCATIONS. THIS STRATUS MAY BEGIN TO BREAK UP SUNDAY MORNING AS THE FRONTAL BOUNDARY BEGINS TO APPROACH...AND THE FLOW BECOMES MORE SW. CONDITIONS SHOULD GO BACK TO VFR AT ALL SITES BY THE LATE MORNING HOURS. SOME SHOWERS AND TSTMS ARE POSSIBLE BY LATE IN THE DAY INTO SUNDAY NIGHT AS THE FRONT CROSSES THE REGION. HAVE INDICATED A VCTS FOR ALL TAF SITES AFTER 18Z-20Z/SUN...AS THUNDERSTORMS SHOULD BECOME RATHER NUMEROUS LATER THIS AFTERNOON...WELL INTO THIS EVENING. IT IS LIKELY THAT SEVERAL DISCRETE ROUNDS OF THUNDERSTORMS OCCUR DURING THIS TIME PERIOD...WITH SOME BREAKS IN BETWEEN. THE THREAT FOR THUNDERSTORMS WILL GRADUALLY DECREASE TOWARD AND ESP AFTER 06Z/MON...FIRST AT KGFL AND KALB...AND LAST AT KPSF AND KPOU. AREAS OF MVFR/IFR FOG MAY OCCUR TOWARD AND AFTER 06Z/MON AT ALL TAF SITES. SOUTH/SOUTHEAST WINDS WILL PERSIST THROUGH DAYBREAK AT KALB AND 8-12 KT...WITH SOME GUSTS POSSIBLY REACHING 15-20 KT. ELSEWHERE...WINDS SHOULD BECOME LIGHT/VARIABLE THROUGH DAYBREAK. WINDS WILL THEN INCREASE FROM THE SOUTH BY MID MORNING AT 8-12 KT...EXCEPT STRONGER...AT 10-15 KT AT KALB...WITH SOME GUSTS OF 20-25 KT POSSIBLE. SOUTH WINDS WILL GRADUALLY VEER INTO THE SW TO W LATER THIS EVENING...AT 5-10 KT. WINDS WILL BE MUCH STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR ANY THUNDERSTORMS. OUTLOOK... SUN NIGHT...MVFR/IFR. SHRA/TSRA LIKELY EARLY. MON...VFR. SLIGHT CHC -SHRA EAST OF THE HUDSON RIVER EARLY IN THE MORNING. TUE...VFR. NO SIG WX. WED...VFR. SLIGHT CHC -SHRA/-TSRA. THU...VFR. CHC OF -SHRA/-TSRA. && .FIRE WEATHER... TONIGHT WILL BE WARM AND MUGGY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST SUNDAY AND CROSS THE REGION AT NIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A COOLER...MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED IN THE WAKE OF THE COLD FRONT. && .HYDROLOGY... TONIGHT WILL BE WARM AND MUGGY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST SUNDAY AND CROSS THE REGION AT NIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A COOLER...MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED IN THE WAKE OF THE COLD FRONT. CONVECTION HAS BEEN FORMING MAINLY ON THE HIGHER TERRAIN OF THE SOUTHERN GREEN MOUNTAINS THIS AFTERNOON. SINCE PRECIPITABLE WATER VALUES ARE HIGH ACROSS AREA HAVE HAD HEAVY RAINFALL WITH SOME STORMS. THERE HAS BEEN TRAINING OF STORMS ALONG THE BERKSHIRE/FRANKLIN COUNTY BORDER. CONVECTION WILL DIMINISH WITH LOSS OF HEATING. VALUES ARE STILLED MODELED TO INCREASE TO 2-2.25 INCHES ACROSS THE AREA AHEAD OF THE APPROACHING COLD FRONT...SO VERY HEAVY/TORRENTIAL DOWNPOURS WILL BE EXPECTED WITH SOME STORMS. THE HEAVY RAINS COULD RESULT IN LOCALIZED FLOODING OF LOW LYING AND POOR DRAINAGE AREAS. AND IF TRAINING OF THUNDERSTORMS OCCURS THEN ISOLATED FLASH FLOODING WOULD BE POSSIBLE. WILL KEEP THIS HIGHLIGHTED IN OUR HAZARDOUS WEATHER OUTLOOK AND KEEP HEAVY RAINFALL MENTIONED IN FORECAST. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/FRUGIS NEAR TERM...FRUGIS/11 SHORT TERM...IAA LONG TERM...ELH AVIATION...KL/FRUGIS FIRE WEATHER...IAA HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS ALBANY NY
127 AM EDT SUN AUG 5 2012 .SYNOPSIS... TONIGHT WILL BE WARM AND MUGGY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST SUNDAY AND CROSS THE REGION AT NIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A COOLER...MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED IN THE WAKE OF THE COLD FRONT FOR EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 120 AM EDT...MAINLY CLEAR SKIES HAVE GIVEN WAY TO PARTLY TO MOSTLY CLOUDY SKIES ACRS THE SRN HLF OF THE FA AS LOW STRATUS HAS STARTED TO LIFT NORTHWARD FROM SOUTHEAST NY AND SW NEW ENGLAND. EXPECT THIS TREND TO CONTINUE WITH SKIES BECOMING PARTLY TO MOSTLY CLOUDY LATER TONIGHT ACRS THE ENTIRE FA. THERE MAY BE SOME RADIATIONAL FOG IN SPOTS...BUT IT WILL DEPEND ON HOW QUICKLY THE STRATUS SPREADS INTO THE REGION. IT WILL REMAIN MUGGY OVERNIGHT...AND MIN TEMPS WILL BE IN THE 70S IN THE CAPITAL REGION OVERNIGHT...WITH MID TO UPPER 60S ELSEWHERE. AN MCS IS CURRENTLY ONGOING ACROSS OHIO. THERE HAS BEEN PLENTY OF CG LTG ACTIVITY WITH THIS STRONG BATCH OF CONVECTION AHEAD OF A POTENT COLD FRONT. THE 00 UTC NAM AND LATEST 01 UTC 3KM HRRR DO NOT HAVE A GOOD HANDLE ON THIS CURRENT ONGOING ACTIVITY. CONSIDERING THAT THE UPPER TROUGH APPEARS TO BE IN THE PROCESS OF SHEARING OUT...WE DON/T ANTICIPATE THIS ACTIVITY MAKING IT INTO OUR AREA BY THE LATE NIGHT HOURS...BUT WE WILL CONTINUE TO MONITOR RADAR TRENDS. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... THE STORM PREDICTION CENTER CONTINUES TO HAVE THE FORECAST AREA IN A SLIGHT RISK FOR THUNDERSTORMS IN THE DAY 2 OUTLOOK. HOWEVER TO NOTE THE AREA OUTLINED BY THE 30 PERCENT COMBINED PROBABILISTIC OUTLOOK FOR SEVERE WEATHER HAS BEEN DECREASED. ALL BUT THE NORTHWEST CORNER OF OUR FORECAST AREA IS NOW UNDER THE 15 PERCENT PROBABILISTIC OUTLOOK. THE MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH THE TIMING OF THE COLD FRONT WHICH WILL NOT CROSS THE AREA UNTIL SUNDAY NIGHT. THE UPPER TROUGH AXIS WILL MOVE ACROSS THE GREAT LAKES REGION DURING THE DAYTIME AND ACROSS EASTERN CANADA SUNDAY NIGHT. NOT MUCH IN THE WAY OF HEIGHT FALLS WILL OCCUR ACROSS OUR REGION. THE BEST DYNAMICS WILL REMAINS JUST TO OUR NORTH AND WEST. MID LEVEL LAPSE RATES WILL BE RATHER WEAK AROUND 5.5 C/KM. MODELS INDICATE MARGINAL INSTABILITY. 500 MB TEMPERATURES WILL WARM TO AROUND -6C WHICH WILL LIMIT DESTABILIZATION. THE 0-6KM BULK SHEAR OF 20 TO 25 KNOTS WILL INCREASE TO 30 TO 40 KNOTS SUNDAY NIGHT. HAVE POPS INCREASING TO LIKELY DURING THE AFTERNOON INTO THE EVENING HOURS. VALUES ARE STILLED MODELED TO INCREASE TO 2-2.25 INCHES ACROSS THE AREA AHEAD OF THE APPROACHING COLD FRONT...SO VERY HEAVY/TORRENTIAL DOWNPOURS WILL BE EXPECTED WITH SOME STORMS. THE HEAVY RAINS COULD RESULT IN LOCALIZED FLOODING OF LOW LYING AND POOR DRAINAGE AREAS. AND IF TRAINING OF THUNDERSTORMS OCCURS THEN ISOLATED FLASH FLOODING WOULD BE POSSIBLE. WILL KEEP THIS HIGHLIGHTED IN OUR HAZARDOUS WEATHER OUTLOOK AND KEEP HEAVY RAINFALL MENTIONED IN FORECAST. THE HOT AND HUMID AIRMASS WILL BE REPLACED BY A COOLER...MORE SEASONABLE AND DRIER AIRMASS TO START THE WEEK. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HPC GUIDANCE. ANOTHER INCLEMENT SUMMER PATTERN SETS UP WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY FROM THURSDAY THROUGH THE END OF THE WEEK. LOW PRESSURE OFF THE CANADIAN ROCKIES WILL TRACK FROM THE NORTHERN PLAINS THROUGH THE GREAT LAKES REGION THROUGH SATURDAY. A COLD FRONT AHEAD OF THE LOW PRESSING SOUTH ACROSS THE FORECAST AREA ON THURSDAY BEGINS THE PATTERN. JUST AHEAD OF THE LOW ON SATURDAY IT RETURNS AS A WARM FRONT...WITH THE MAIN COLD FRONT SLIDING EAST ACROSS THE AREA EARLY SATURDAY. THE TIMING OF THIS LATTER FRONTAL PASSAGE WILL DECIDE THE EXTEND OF ANY REMAINING THUNDERSTORM ACTIVITY ON SATURDAY AS HIGH PRESSURE WILL BE MAKING A RETURN. HIGH TEMPERATURES WEDNESDAY AND THURSDAY WILL RANGE MAINLY FROM AROUND 80 DEGREES IN THE HIGH ELEVATIONS...TO AROUND 90 IN THE MOHAWK AND HUDSON VALLEYS. HIGHS FRIDAY WILL BE FROM THE MID 70S TO MID 80S...WITH SLIGHTLY COOLER READINGS FOR SATURDAY. LOWS WILL START OFF TUESDAY NIGHT FROM MAINLY THE UPPER 50S TO MID 60S. THE NIGHT WILL BECOMING INCREASINGLY MILDER...HOWEVER...WITH LOWS FRIDAY NIGHT MAINLY FROM THE MID 60S TO AROUND 70 DEGREES. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS ARE IN PLACE AT ALL TAF SITES THIS EVENING WITH JUST FEW CU STILL AROUND. SKIES MAY BRIEFLY GO CLEAR FOR THE EVENING HOURS WHICH WILL ALLOW FOR SOME RADIATIONAL COOLING AS THESE CU DISSIPATE WITH THE LOSS OF DAYTIME HEATING. THIS MAY LEAD TO SOME RADIATIONAL FOG STARTING TO DEVELOP...MAINLY FOR THE TYPICAL SPOTS /KGFL AND KPSF/ TOWARDS OR JUST AFTER MIDNIGHT. AT THE SAME TIME...A SOUTHERLY FLOW WILL ADVECT WARM AND MOIST AIR INTO THE REGION FROM THE ATLANTIC. THIS WILL ALLOW SOME IFR STRATUS TO DEVELOP OVERNIGHT. STRATUS WILL DEVELOP FIRST IN THE SOUTH BY KPOU/KPSF BY AROUND 06Z...AND MOVE UP THE HUDSON VALLEY DURING THE REMAINDER OF THE OVERNIGHT HOURS. EVEN KALB/KGFL MAY SEE SOME IFR STRATUS TOWARDS THE LATE NIGHT HOURS. THIS STRATUS MAY BEGIN TO BREAK UP ON SUNDAY MORNING AS A FRONTAL BOUNDARY BEGINS TO APPROACH...AND THE FLOW BECOMES MORE WSW. CONDITIONS SHOULD GO BACK TO VFR AT ALL SITES BY THE LATE MORNING HOURS. SOME SHOWERS AND EVEN TSTMS ARE POSSIBLE BY LATE IN THE DAY OR SUNDAY NIGHT AS THE FRONT CROSSES THE REGION. DUE TO UNCERTAINTY REGARDING TIMING/EXTENT OF SHOWERS/STORMS...WILL ONLY GO WITH A VCSH AT THIS TIME FOR THE AFTN HOURS AT ALL SITES. OUTLOOK... SUN NIGHT...MVFR/IFR. SHRA/TSRA LIKELY. MON...VFR. SLIGHT CHC -SHRA EAST OF THE HUDSON RIVER EARLY IN THE MORNING. TUE...VFR. NO SIG WX. WED...VFR. SLIGHT CHC -SHRA/-TSRA. THU...VFR. CHC OF -SHRA/-TSRA. && .FIRE WEATHER... TONIGHT WILL BE WARM AND MUGGY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST SUNDAY AND CROSS THE REGION AT NIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A COOLER...MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED IN THE WAKE OF THE COLD FRONT. && .HYDROLOGY... TONIGHT WILL BE WARM AND MUGGY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST SUNDAY AND CROSS THE REGION AT NIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A COOLER...MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED IN THE WAKE OF THE COLD FRONT. CONVECTION HAS BEEN FORMING MAINLY ON THE HIGHER TERRAIN OF THE SOUTHERN GREEN MOUNTAINS THIS AFTERNOON. SINCE PRECIPITABLE WATER VALUES ARE HIGH ACROSS AREA HAVE HAD HEAVY RAINFALL WITH SOME STORMS. THERE HAS BEEN TRAINING OF STORMS ALONG THE BERKSHIRE/FRANKLIN COUNTY BORDER. CONVECTION WILL DIMINISH WITH LOSS OF HEATING. VALUES ARE STILLED MODELED TO INCREASE TO 2-2.25 INCHES ACROSS THE AREA AHEAD OF THE APPROACHING COLD FRONT...SO VERY HEAVY/TORRENTIAL DOWNPOURS WILL BE EXPECTED WITH SOME STORMS. THE HEAVY RAINS COULD RESULT IN LOCALIZED FLOODING OF LOW LYING AND POOR DRAINAGE AREAS. AND IF TRAINING OF THUNDERSTORMS OCCURS THEN ISOLATED FLASH FLOODING WOULD BE POSSIBLE. WILL KEEP THIS HIGHLIGHTED IN OUR HAZARDOUS WEATHER OUTLOOK AND KEEP HEAVY RAINFALL MENTIONED IN FORECAST. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA/FRUGIS NEAR TERM...FRUGIS/11 SHORT TERM...IAA LONG TERM...ELH AVIATION...FRUGIS FIRE WEATHER...IAA HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1152 PM CDT SAT AUG 4 2012 .DISCUSSION... ISSUED 900 PM CDT SAT AUG 4 2012 HI RES MODELS ARE STILL INDICATING WE SHOULD SEE SOME STORM DEVELOPMENT ALONG THE COLD FRONT LATE THIS EVENING AND AFTER MIDNIGHT. INSTABILITY PARAMS CONTINUE TO LOOK FAVORABLE FOR STORMS AHEAD OF THE FRONT EVEN INTO CENTRAL AND SOUTHEAST IL. WE WILL CONTINUE WITH AT LEAST HIGH CHANCE POPS...ALTHOUGH WE MAY PULL BACK ON THE LIKELY POPS...OR DIMINISH THE COVERAGE OF LIKELY POPS. CAN NOT RULE OUT A FEW STRONG STORMS WITH DAMAGING WINDS POSSIBLE. STORMS IN EAST CENTRAL MISSOURI HAVE REACHED SEVERE LEVELS AND THEY ARE APPROACHING SW ILLINOIS. THEIR PROGRESSION WOULD MOSTLY LIKELY HAVE THEM AFFECTING OUR SOUTHEASTERN COUNTIES. VARIABLE CLOUD COVER THE REST OF THE NIGHT...COUPLED WITH COLDER AIR LAGGING WELL BEHIND THE COLD FRONT...SHOULD SET THE STAGE FOR LOWS TO REMAIN IN THE UPPER 60S TO LOW 70S. DRY AND NOT AS HOT FOR SUNDAY...WITH SUNDAY NIGHTS LOWS DIPPING INTO THE 50S. MAIN UPDATES WERE TO THE POP AND WEATHER GRIDS. UPDATED INFO WILL BE AVAIL SHORTLY. SHIMON && .AVIATION... ISSUED 1152 PM CDT SAT AUG 4 2012...FOR THE 06Z TAFS IT APPEARS THAT THE COLD FRONT IS BECOMING ACTIVE AGAIN...BUT ANY STORMS SHOULD MAINLY AFFECT AREAS EAST OF I-55. SO WE INCLUDED VCTS AT SPI, DEC AND CMI FOR THE FIRST 2-3 HOURS OF THIS TAF PERIOD. BMI APPEARS TO BE CLEAR OF ANY MORE THUNDERSTORMS. WINDS HAVE BECOME NORTH AT ALL TERMINALS EXCEPT DEC AND CMI...WHO ARE STILL AHEAD OF THE FRONT. THE SOUTHERLY WINDS AT DEC AND CMI SHOULD REMAIN BELOW 10KT EXCEPT FOR IN THE VICINITY OF THUNDERSTORMS...THEN WINDS WILL BECOME NNW BEHIND THE FRONT. SOME LIGHT MVFR FOG MAY DEVELOP EVEN BEHIND THE FRONT AS SURFACE DEWPOINTS REMAIN HIGH WELL BEHIND THE COLD FRONT. AS TEMPS DROP AND SKIES CLEAR OUT...DEWPOINT DEPRESSIONS WILL DIP INTO THE 2-3F RANGE. NORTH WINDS TOMORROW WILL INCREASE INTO THE 12-14KT RANGE AS HIGH PRESSURE BUILDS SOUTH INTO ILLINOIS. SHIMON && .PREV DISCUSSION... ISSUED 341 PM CDT SAT AUG 4 2012 COLD FRONT HAS BEEN MOVING A BIT QUICKER TOWARD THE CWA...AND WAS LOCATED FROM NEAR THE QUAD CITIES SOUTHWEST TO NEAR KANSAS CITY. WELL-DEFINED MESOSCALE VORTEX FROM CONVECTION IN IOWA HELPED TO DEVELOPED AN MCS WHICH HAS BEEN ROLLING ACROSS THE NORTHERN THIRD OF ILLINOIS THIS AFTERNOON. SOME OF THE SOUTHERN FRINGES CONTINUE TO PUSH ACROSS AREAS FROM CANTON EAST TO EL PASO AT MID AFTERNOON. INSTABILITY OVER THE AREA PEAKED EARLY THIS AFTERNOON WITH CAPES AROUND 4000 J/KG...BUT SPC MESO-ANALYSIS HAS BEEN SHOWING SOME DECREASE IN CAPES AND INCREASE IN CAPPING ALOFT. HOWEVER...STILL QUITE A BIT OF INSTABILITY AVAILABLE FROM SOUTHERN MISSOURI NORTHEAST INTO EAST CENTRAL ILLINOIS. LATEST NAM AND HRRR SHOW DEVELOPMENT OCCURRING IN THESE AREAS OVER THE NEXT COUPLE HOURS. WILL MAINTAIN LIKELY POPS OVER A LARGE PART OF THE CWA THIS EVENING...THEN LIMIT THEM TO 40-50 PERCENT AFTER MIDNIGHT ACROSS THE EAST CENTRAL AND SOUTHEAST CWA. ANY LINGERING RAIN ACROSS THE FAR SOUTHEAST WILL LIKELY BE ENDING BEFORE SUNRISE. LITTLE CHANGE MADE TO THE REMAINDER OF THE FORECAST. BRIEF COOL DOWN WILL BE NOTED EARLY THIS WEEK AS HIGH PRESSURE DRIFTS EAST ACROSS THE AREA. A SLOW WARMING TREND WILL BRING TEMPERATURES BACK TO NEAR 90 MUCH OF THE REMAINDER OF THE WEEK...WITH HOTTER WEATHER KNOCKING ON THE DOOR AS WE REMAIN ON THE FRINGE OF THE UPPER RIDGING ACROSS THE WESTERN HALF OF THE NATION. MAIN FEATURE OF CONCERN IN THE LONG RANGE IS ON THURSDAY AND FRIDAY...WHEN A PIECE OF ENERGY DROPS SOUTHEAST OUT OF THE CANADIAN PRAIRIES. GFS AND ECMWF NOT TOO FAR APART WITH THE TRACK OF THIS SHORTWAVE OVER THE GREAT LAKES...BUT THE GFS IS MORE AGGRESSIVE WITH BRINGING RAIN CHANCES ALL THE WAY SOUTH ACROSS ILLINOIS. WILL KEEP SOME SLIGHT CHANCES IN THE GRIDS THURSDAY AND THURSDAY NIGHT...BUT WILL LEAN MORE TOWARD THE ECMWF WITH ITS ODDS OF DRY WEATHER. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
432 AM EDT SUN AUG 5 2012 .SHORT TERM...(TONIGHT) ISSUED AT 432 PM EDT SAT AUG 4 2012 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS LOOKING SHORTWAVE TROF ACROSS THE ERN DAKOTAS/MN. AT THE SFC...ASSOCIATED COLD FRONT IS SLICING THRU WRN LAKE SUPERIOR/WRN UPPER MI AND NW WI. DESPITE VIGOROUS LOOK OF SHORTWAVE...CONVECTION HAS BEEN KEPT IN CHECK BY ABUNDANT CLOUD COVER THAT HAS PERSISTED THRU THE DAY ACROSS GOOD PORTIONS OF UPPER MI AND NRN WI. LATEST SPC MESOANALYSIS SHOWS MLCAPE OF MOSTLY UNDER 500J/KG ACROSS THE FCST AREA. HIGHEST VALUES...A LITTLE OVER 500J/KG...ARE OVER THE E WHERE THERE HAS BEEN MORE SUNSHINE WITH SFC DWPTS AROUND 70F. IF MORE INSTABILITY HAD DEVELOPED...A FAIRLY SIGNIFICANT SVR WEATHER OUTBREAK WOULD PROBABLY BE GETTING UNDERWAY ACROSS THE FCST AREA AS DEEP LAYER SHEAR IS STEADILY INCREASING TOWARD THE 40-50KT RANGE DUE TO MIDLEVEL SPEED MAX APPROACHING THE AREA. MAIN SHOW TONIGHT WILL BE S OF THE AREA WITH CONVECTIVELY ENHANCED SHORTWAVE TRACKING TOWARD SRN WI/NRN IL/LWR MI. THE ONGOING ASSOCIATED CLUSTER OF STRONG/SVR STORMS WILL PASS S OF THE AREA. THAT SAID...OVER THE NEXT FEW HRS...SHRA/TSRA SHOULD TEND TO EXPAND NE ACROSS ROUGHLY THE E HALF OF THE FCST AREA AS HEIGHT FALLS AND RIGHT ENTRANCE OF UPPER JET STREAK WORK TO INCREASE UPWARD MOTION. THERE IS STILL THE POTENTIAL OF ISOLD SVR STORMS...BUT WITH CLOUD COVER NOW INCREASING EVEN OVER THE ERN FCST AREA TO PREVENT INSTABILITY FROM BUILDING HIGHER...IT APPEARS RISK OF SVR STORMS IS DIMINISHING. WILL KEEP SLIGHT RISK OF SVR WORDING IN HAZARDOUS WX OUTLOOK FOR THE NEXT FEW HRS OR SO. AFTER ANY SHRA/TSRA WITH COLD FRONT DEPART...ATTENTION TURNS TO VORT MAX AND SECONDARY COLD FRONT THAT WILL SWING INTO THE AREA LATE TONIGHT. THERE HAS BEEN FAIRLY SOLID COVERAGE OF SHRA AND EVEN SCT TSRA ACROSS SE MANITOBA INTO ADJACENT NRN ONTARIO WITH TROF AXIS THOUGH PCPN HAS TAKEN ON MORE OF A DIURNAL SCT COVERAGE THIS AFTN. AS TROF AXIS/VORT MAX DROP INTO THE AREA...THERE SHOULD BE DECENT SHRA COVERAGE LATE TONIGHT INTO SUN MORNING...ESPECIALLY SINCE CAA DROPS 850MB TEMPS TO AROUND 6C BY 12Z SUN. WITH WATER TEMPS AROUND 20C ON LAKE SUPERIOR...THE OVERWATER INSTABILITY WILL BE MORE THAN SUFFICIENT FOR LAKE ENHANCEMENT UNDER CYCLONIC FLOW WITH ARRIVAL OF VORT MAX. THUS...EXPECT SCT/NMRS SHRA TO DEVELOP LATE TONIGHT OVER THE NW HALF OF UPPER MI. AS ALWAYS...UPSLOPE NW WINDS WILL LEAD TO MOST NMRS COVERAGE OVER THE HIGHER TERRAIN DOWNWIND OF THE LAKE. .LONG TERM...(SUNDAY THROUGH SATURDAY) ISSUED AT 432 PM EDT SAT AUG 4 2012 GOOD AGREEMENT FM THE GFS/ECMWF/GEM-NHEM WITH OVERALL UPPER AIR PATTERN THROUGH THIS WEEK. PATTERN STARTS OFF WITH DEEP TROUGH OVER THE UPPER GREAT LAKES AND BROAD WEST-TO-EAST RIDGE ACROSS THE SOUTHERN TIER OF THE CONUS. BY MIDWEEK...RIDGE BECOMES MORE AMPLIFIED OVER INTERMOUNTAIN WEST INTO WESTERN CANADA WHILE TROUGHING REMAINS IN PLACE OVER EASTERN CANADA AND THE GREAT LAKES AND NORTHEAST CONUS. WEATHER WILL STAY ON THE ACTIVE SIDE AS MULTIPLE SYSTEMS IMPACT THE UPPER GREAT LAKES. FIRST WILL BE RIGHT AT BEGINNING OF LONG TERM ON SUNDAY. ANOTHER WEAKER COLD FRONT COMES THROUGH AREA ON TUESDAY. MUCH STRONGER LOW PRESSURE SYSTEM FCST TO PUSH ACROSS GREAT LAKES LATER THURSDAY INTO FRIDAY. IT IS THIS SYSTEM THAT SHOWS THE MOST POTENTIAL TO PRODUCE NOTEABLE PRECIPITATION AMOUNTS IN THE LONG TERM. SINCE THE LARGE TROUGH IS CLOSE BY AND RIDING REMAINS WELL TO THE WEST...EXPECT TEMPERATURES TO GENERALLY BE WITHIN A FEW DEGREES OF NORMAL. ONLY WARM EXCEPTION WILL BE ON MONDAY AHEAD OF ANOTHER COLD FRONT. SOME COOL PERIODS ARE EXPECTED AS WELL. COOLEST OF THE BUNCH LIKELY WILL BE ON SUNDAY...BUT SIMILAR COOLER TEMPERATURES MAY OCCUR AGAIN ON FRIDAY ON IN WAKE OF LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES. A VERY CHAGEABLE WEATHER DAY IS IN STORE FOR SUNDAY. COLD FRONT THROUGH UPR MICHIGAN BY DAYBREAK WHILE SFC LOW PUSHES ACROSS JAMES BAY. COOL AND MOIST CYCLONIC FLOW SFC THROUGH H7 AFFECTS MOST CWA THROUGH LATE MORNING THEN HEIGHTS RISE QUICKLY WHILE EDGE OF SFC HIGH BUILDS IN MID-LATE AFTN. MOIST CYCLONIC FLOW AND THERMAL TROUGH WITH H85 TEMPS AS LOW AS +5C IN ADDITION TO A SHARP SECONDARY WAVE DROPPING THROUGH MEAN TROUGH SHOULD COMBINE TO BRING A PERIOD OF SHOWERS TO PORTIONS OF CWA THROUGH THE MORNING. WARM LK SUPERIOR TEMPS NEAR +20C ALSO ALLOW LAKE EFFECT PROCESSES TO ENHANCE PCPN AS DELTA T/S ARE AROUND 14-15C/LAKE INDUCED CAPES UP TO 250 J/KG. INCREASED POPS OVER UPSLOPE AREAS FAVORED BY NW BLYR WINDS. HIGHEST POPS IN THE MORNING...THEN RAPIDLY DROPPING OFF IN THE AFTN AS AREA QUICKLY RESIDES IN SUBSIDENCE REGION OF THE STRONG SHORTWAVE. SKIES PROBABLY CLEAR QUICKLY IN THE AFTN DUE TO SUBSIDENCE AND DRY AIR. TEMPS KIND OF TRICKY...BUT FOLLOWED TREND CLOSER TO GEM-REGIONAL SHOWING TEMPS STUCK IN THE MID 50S-LOW 60S INTO EARLY AFTN...THEN RISING TOWARD 70 DEGREES LATER IN THE DAY WITH INCREASING SUNSHINE. GUSTY WINDS OTHER FACTOR ON SUNDAY AS DEEP MIXING EXPECTED THROUGH EARLY AFTN BEFORE H85 WARM ADVECTION INCREASES STABILITY. MIXED LAYER WINDS THROUGH 16Z 35-40KT AND EXPECT GOOD PORTION OF THESE TO MIX TO SFC. STRONGEST WINDS NEAR EXPOSED LK SUPERIOR SHORE OF CNTRL AND EAST. EXPECT WINDS TO DIMINISH BY LATE DAY. HIGH PRESSURE AXIS REMAINS JUST SOUTH OF AREA SUNDAY NIGHT BUT WINDS BECOME LIGHT ENOUGH/PWAT LOW ENOUGH TO SEE SOME RADIATIONAL COOLING TAKE PLACE. LOWEST MINS SEEM LIKELY IN THE INTERIOR CNTRL AND EAST WHERE COLD SPOTS MAY DROP INTO LOWER 40S. MUCH DIFFERENT DAY ON MONDAY COMPARED TO COOLER/WINDY DAY ON SUNDAY. HIGH PRESSURE SLIDES EAST AND A WEAK COLD FRONT IS FCST TO DROP INTO UPR LAKES MONDAY NIGHT. NOT A LOT OF CLOUD COVER AHEAD OF FRONT THOUGH OTHER THAN ON THE KEWEENAW IN THE LATER AFTN. WITH H85 TEMPS 15C-16C EXPECT HIGHS TO REACH WELL INTO THE 80S AWAY FM LK MICHIGAN SHORE. AS UPR JET SLIDES ACROSS ONTARIO MONDAY NIGHT AND MID-LEVEL FGEN INCREASES OVR LK SUPERIOR...EXPECT BAND OF SHRA/TSRA TO DEVELOP ALONG SFC FRONT. FRONT SLIDES THROUGH CWA ON MONDAY NIGHT...WITH BETTER CHANCES OF SHRA/TSRA TIED INTO THE MID-LEVEL FORCING. SOUNDINGS SHOW DRY AIR LINGERING BLO H85-H7 DUE TO LIMITED MOISTURE ADVECTION FM THE GULF INTO THIS SYSTEM. SO...COVERAGE OF PRECIP WILL BE SPOTTY WITH THE FRONT. HIGH PRESSURE BUILDS BACK IN FOR TUESDAY WITH TEMPS IN THE 70S NORTH AND NEARING 80 DEGREES OVR THE SOUTH AND NEAR LK MICHIGAN. EXTENDED...MAIN CHANCES FOR SHRA/TSRA COME IN LATER WEDNESDAY NIGHT INTO THURSDAY AS ANOTHER UPPER LOW AND SFC LOW MOVE ACROSS THE UPR LAKES. CYCLONIC FLOW LINGERING IN THE WAKE OF THE SFC LOW COULD KEEP SOME SHRA GOING OVR THE AREA INTO FRIDAY...KIND OF SIMILAR TO WHAT IS EXPECTED ON SUNDAY. WITH EXPECTED CLOUDS/PCPN...TRIMMED TEMPS THURSDAY AND FRIDAY CLOSER TO LK SUPERIOR WHERE ONSHORE NORTHEAST FLOW SHOULD RESULT IN COOLER CONDITIONS. INCREASED WINDS OVR LK SUPERIOR SOME COMPARED TO GUIDANCE CONSENSUS BUT MAY NEED TO INCREASE FURTHER WITH LATER FCSTS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 431 AM EDT SUN AUG 5 2012 FIRST COLD FRONT HAS PASSED THROUGH ALL THREE TAF SITES WITH SECOND COLD FRONT PUSHING INTO KIWD. A SURGE OF COLDER AIR AT 850 MB ASSOCIATED WITH THIS SECOND COLD FRONT WILL BRING GUSTY WINDS TO ALL THREE SITES AND IFR CIGS AND ASSOCIATED LAKE EFFECT SHOWERS TO KIWD AND KCMX. CIGS TO APPROACH IFR AT KSAW BUT WITH SLIGHT DOWNSLOPE TO WIND DIRECTION THEY SHOULD STAY JUST ABOVE IFR. FRONT SHOULD MOVE THROUGH KCMX BY 7Z AND REACH KSAW AROUND 9Z. AS THE GRADIENT TIGHTENS UP...EXPECT TO SEE GUSTY NW WINDS TO 25-30KT. PRESSURE GRADIENT WILL RELAX RATHER QUICKLY THIS AFTERNOON AS THE LOW MOVES AWAY FROM THE REGION. SKIES WILL CLEAR RATHER QUICKLY AS DECENT SUBSIDENCE ARRIVES WITH SKIES BECOMING VFR AROUND 16Z AT KIWD AND KCMX SOON AFTER...WITH CLEARING REACHING KSAW AROUND 18Z. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 432 PM EDT SAT AUG 4 2012 COLD FRONT PASSES ACROSS LK SUPERIOR THIS EVENING. PERIOD OF STRONG WINDS AND HIGH WAVES /LIKELY OVR 10 FEET/ EXPECTED LATE TONIGHT THROUGH MUCH OF SUNDAY AFTERNOON. EXPECT 25-30 KT WINDS FM THE NORTHWEST DURING ON SUNDAY WITH FREQUENT GALE GUSTS 35-40 KTS. A GALE WATCH HAS BEEN POSTED FOR THE EAST HALF OF LK SUPERIOR MOST OF SUNDAY. WINDS DIMINISH SUNDAY NIGHT...BUT THEN INCREASE FM THE SOUTHWEST ON MONDAY AHEAD OF A COLD FRONT THAT SLIDES THROUGH ON MONDAY NIGHT. IN WAKE OF THE FRONT...EXPECT WINDS 20 KTS OR LESS TUESDAY INTO WEDNESDAY AS HIGH PRESSURE MOVES ACROSS THE REGION. WINDS MAY END UP STRONGER THAN FCST FOR LATE THIS WEEK AS DETAILS ARE SORTED OUT REGARDING ANOTHER LOW PRESSURE SYSTEM MOVING THROUGH THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 8 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR LSZ251-267. GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249-250-266. GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ244-245-264- 265. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...JLA AVIATION...RJT MARINE...JLA
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
251 AM CDT SUN AUG 5 2012 .SHORT TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (TODAY AND TONIGHT) FOCUS INITIALLY WILL BE ON EXITING THUNDERSTORMS. LATEST RUNS OF THE RAP SEEM TO BE IN LINE WITH CURRENT EXTRAPOLATION THAT SURFACE FRONT WILL BE RIGHT ALONG THE SOUTHERN BORDER OF THE CWA AT 12Z. AXIS OF SHORTWAVE TROUGH CURRENTLY ALONG THE KS/MO BORDER WILL BE OVER SOUTHEASTERN MO WITH SOME LINGER 925-850 ALONG AND JUST NORTH OF THE SFC FRONT. HAVE ISOLATED/SCATTERED THUNDERSTORMS SLOWLY PUSHING SOUTH OF THE CWA BETWEEN 12-18Z BEFORE SUBSIDENCE SETS IN BEHIND THE SHORTWAVE. CLOUDS WILL ALSO DECREASE THROUGH MIDDAY AS LOW-MID LEVEL MOISTURE AND CONVECTIVE DEBRIS MOVES OUT OF THE AREA. STAYED WITH THE BETTER VERIFYING NAM MOS HIGHS TODAY...PARTICULARLY WHERE THERE SHOULD BE THE MOST SUN. SKIES WILL BE CLEAR TONIGHT AND WINDS SHOULD TURN LIGHT EASTERLY BY MORNING AS SURFACE HIGH CENTER PASSES THROUGH NORTHERN MO/CENTRAL IL. CAN`T RULE OUT SOME FOG DEVELOPING IN AREAS THAT HAD THE HEAVIEST RAINFALL THE PAST 24 HOURS LATE TONIGHT/EARLY MONDAY. BRITT && .LONG TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (MONDAY THROUGH SATURDAY) DRY WEATHER WILL BE THE RULE MONDAY AND TUESDAY AS LOW LEVEL MOISTURE WILL BE CUT OFF BY FRONT MOVING THROUGH TODAY AND AREA WILL BE UNDER MAINLY SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT. NAM/GFS BOTH SHOW A TROUGH MOVING ACROSS THE MIDWEST ON TUESDAY...BUT THE BEST ASCENT WILL STAY TO THE NORTH OF THE AREA AS IT BEGINS TO SHEAR OUT. STAYED CLOSER TO THE NAM MOS FOR HIGHS AS FORECAST SOUNDINGS ARE SHOWING MIXING UP TO 800MB ON MONDAY AND 700MB ON TUESDAY. LOWER 90S SEEM REASONABLE ON MONDAY WITH 850MB TEMPS NEAR 20C...AS DO MIDDLE TO POSSIBLY UPPER 90S ON TUESDAY WITH 20-24C 850MB TEMPS. DOES LOOK LIKE DEWPOINTS WILL STAY IN THE 50S DURING THE PERIOD WHICH SHOULD KEEP HEAT INDEX READINGS AT OR BELOW THE AMBIENT TEMPERATURES. THE GFS IS SHOWING A DEEPER TROUGH DIGGING IN OVER THE MISSISSIPPI VALLEY ON THURSDAY THAN IT DID PREVIOUSLY. ECMWF/CANADIAN GEM SHOW A LESS AMPLIFIED AND SLOWER SOLUTION...SO GOING SLIGHT CHANCES FOR THUNDERSTORMS SEEM THE BEST ROUTE. THEN GFS IS SHOWING ANOTHER SORTHWAVE MOVING DOWN TOWARD THE AREA BY EARLY NEXT WEEKEND WITH THE ECMWF HAVING A SLOWER SOLUTION...SO AGAIN SLIGHT CHANCES SEEM THE BEST ROUTE. 850MB TEMPS ARE SHOWING A SLOW DECLINE FROM WEDNESDAY TO SATURDAY AS 500MB HEIGHTS SLOWLY FALL WITH THE PASSAGE OF THE SHORTWAVES...SO HAVE TEMPERATURES FALLING FROM THE LOWER-MID 90S ON THURSDAY INTO MAINLY IN THE 80S ON SATURDAY. BRITT && .AVIATION... ISSUED AT 630 PM CDT SAT AUG 4 2012 VFR CONDITIONS EXPECTED OUTSIDE OF ANY TSRA. SFC LOW CURRENTLY JUST SSE OF KUIN WITH A CDFNT STRETCHING SWWD JUST S OF KJEF TO JUST N OF KJLN. EXPECT ONGOING TSRA TO CONTINUE EWD AHEAD OF THIS FNT. LATEST TRENDS SUGGEST THAT TSRA DEVELOPMENT FURTHER N...IMPACTING KCOU/KSUS/KCPS...IS UNLIKELY TO OCCUR WITH THE CDFNT. HOWEVER...THERE IS STILL A CHANCE THAT AS THE SFC FNT STALLS ALONG A COU TO SUS/CPS LINE...SOME SHRA/TSRA WILL DEVELOP LATE THIS EVENING. DUE TO THE LOW PROBABILITY...WILL COVER WITH A VCTS FOR NOW. EXPECT COU TO REMAIN DRY THRU THE PERIOD UNLESS THE ABOVE SCENARIO DEVELOPS. POST-FRONTAL PRECIP ACROSS NRN MO SHUD REACH UIN IN A COUPLE OF HOURS. LATEST TRENDS SUGGEST THIS MAY BE LITTLE MORE THAT A LIGHT SHOWER BY THE TIME IT REACHES THE TERMINAL. WILL MONITOR AS IT APPROACHES. FOR SUN...SFC RIDGE WILL GRADUALLY BUILD INTO THE REGION WITH NLY TO NNWLY WINDS AROUND 12 KTS. ANY CLOUDS IN THE MORNING SHUD CLEAR OUT. SPECIFICS FOR KSTL...TIMING OF ANY PRECIP TONIGHT IS UNCERTAIN...IF IT DOES DEVELOP. HAVE MENTION OF VCTS FOR BEST CHANCES. WINDS WILL BECOME NWLY TO NNWLY BEHIND APPROACHING CDFNT. CLOUDS SHUD GRADUALLY CLEAR OUT LATE TONIGHT INTO SUN MORNING WITH NLY WINDS PICKING UP TO AROUND 12KTS. EXPECT VFR CONDITIONS OUTSIDE OF ANY TSRA. TILLY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1144 PM CDT Sat Aug 4 2012 ...UPDATED AVIATION DISCUSSION... .DISCUSSION... Well, looks like we have to wait for rain again. At least in many areas this seems to be the appropriate theme for today, as yet another shortwave/MCV race ahead of the surface front this morning effectively shoving stabilizing much of northern Missouri and allowing a weak surface trough to sneak southeast into Missouri and Kansas. Currently the primary surface trough stretches from Ottumwa, IA southwest through Kansas City and further south towards Wichita, KS. A continued stream of mid-level strato-cu has suppressed the warm surface temperatures in the extreme southern CWA with 88D radar composites indicating northward extent of surface warm front is just south of the Pleasant Hill office. For tonight, highest convective potential remains along our southern and southeastern tier of counties and again in areas near Kirksville as mid-level shortwave currently moving through central Kansas reaches the area after 4pm. HRRR and RAP suggest widely scattered convection forming along the differential heating axis in the southern CWA after 4pm with this convection slowly sinking southeast this evening. Instability and shear plots indicate multi-cell clusters would be the preferred storm type with downburst winds the main threat. Elsewhere in areas further north, scattered high based showers or sprinkles may the result of the weak shortwave and 850 trough passing through the area this evening. Dew points will remain elevated through the evening as true front is just arriving into the northwest corner of the CWA. Will linger chc pops across the southern CWA through the overnight hours, as 850 mb front stalls. Weak 850:700 mb frontogenesis tied with the right entrance region of the upr jet may be enough forcing for west to east ling of elevated convection through early Sunday morning in west central into central MO. Sunday-Monday: Surface high pressure will drift southeast into the region by Sunday morning. North to northeast winds will prevail through the daytime hours with temperatures struggling to reach the middle 80s in northern MO and barely hitting 90 towards east central Kansas and central MO. This surface ridge will quickly slide into the Ohio river valley by Monday allowing winds to take a more southerly track. The resultant bump in low-level temperatures will push daytime highs in the lower to middle 90s. Tuesday-Friday: The overall longwave pattern will feature a building ridge over the western CONUS and broad northwesterly flow over the central and eastern US. GFS/EC/GEM indicate a weak disturbance in the NW flow pattern moving through as we reach Tuesday night into Wednesday. Always hard to time these shortwaves and their impact especially considering the lack of boundary layer moisture. However one could justify at least a slight chance for precip. Temperatures will run near or slightly above normal through the end of the week. 31 && .AVIATION... Convection continues to remain well south of the terminals this evening. Otherwise, VFR conditions expected through the remainder of the forecast. Deroche && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1255 AM CDT SUN AUG 5 2012 .AVIATION...06Z KGRI TAF. VFR CONDITIONS TO CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS. LIGHT AND VARIABLE WINDS WILL BECOME MORE ESTABLISHED FROM THE SOUTH DURING THE DAY SUNDAY. LITTLE IN THE WAY OF CLOUD COVER IS CURRENTLY EXPECTED AND VISIBILITY RESTRICTIONS ARE NOT EXPECTED THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 406 PM CDT SAT AUG 4 2012/ SHORT TERM...THROUGH SUNDAY AFTERNOON. PRIMARY ISSUES THROUGH THE NEXT 24 HOURS INCLUDE TIMING THE THE LAST FEW HOURS OF LINGERING ISOLATED/SCATTERED LIGHT PRECIP THROUGH LATE AFTERNOON...FOLLOWED BY JUST HOW COOL WILL IT GET TONIGHT. 19Z OBJECTIVE SURFACE ANALYSIS CENTERS A 1022MB HIGH OVER MT/WY...WITH THE RIDGE AXIS EXTENDING DOWN INTO WESTERN NEB. THE MUCH-AWAITED STRONGEST COLD FRONT WE HAVE SEEN AWHILE HAS PUSHED WELL OFF TO THE SOUTH AND EAST...NOW ALIGNED ALONG FROM EASTERN IA TO THE TX PANHANDLE. ALTHOUGH MID AFTERNOON WINDS CONTINUE TO GUST OVER 20 MPH IN MANY AREAS FROM THE NORTH/NORTHWEST...THEY ARE STARTING A GRADUAL DECLINE AS THE STRONGEST PRESSURE RISES SLIDE SOUTHEAST WITH THE FRONT. RADAR IMAGERY AND VISIBLE SATELLITE AROUND 1930Z GENERALLY CONFIRM THE EARLIER EXPECTATIONS OF ISOLATED/SCATTERED MAINLY LIGHT HIGH BASED RAIN SHOWERS STARTING TO INCREASE IN COVERAGE A BIT ACROSS THE SOUTHERN 1/2 OF THE CWA...ALTHOUGH NO LIGHTNING STRIKES HAVE YET BEEN DETECTED. WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA REVEAL A SEASONABLY STRONG MID LEVEL VORT MAX TRACKING EAST NEAR FAR NORTHERN MN...WITH THE 500MB SHORTWAVE AXIS TRAILING SOUTHWEST TO THE LOCAL AREA...WHILE RIDGING DOMINATES THE SOUTH CENTRAL AND WEST CENTRAL CONUS. TEMP WISE THIS AFTERNOON...STILL ANTICIPATING SOME LATE DAY SUNSHINE TO BOOST AT LEAST MUCH OF THE NORTHWEST 1/2 OF THE CWA INTO THE LOW 80S...BUT THE JURY IS STILL OUT ON WHETHER PARTS OF THE SOUTHEAST...MAYBE EVEN HASTINGS...WILL EVEN MAKE IT TO 80 GIVEN THE EXTENSIVE MID CLOUDS LINGERING LONGER. SEASONABLY DRY AIR IN THE FORM OF MID 40S-LOW 50S DEWPOINTS CONTINUE TO INVADE MUCH OF THE CWA FROM THE NORTHWEST...ALTHOUGH SOME UPPER 50S ARE STILL HANGING ON IN THE SOUTHEAST. STARTING OFF WITH THE NEXT FEW HOURS THROUGH 00Z...JUST MADE A LAST MINUTE DECISION TO PULL THUNDER MENTION ALTOGETHER...AS LATEST HOURLY MESOANALYSIS AND RAP INSTABILITY PROGS INDICATE BARELY EVEN 100 J/KG MUCAPE REMAINING IN THE FAR SOUTHEAST COUNTIES...AND ONGOING LIGHT SHOWERS HAVE NOT EXHIBITED DETECTABLE LIGHTNING AT ALL OVER THE PAST FEW HOURS. THESE LINGERING SHOWERS OVER THE NEXT FEW HOURS WILL MAINLY AFFECT LIMITED AREAS SOUTHEAST OF A LINE FROM HEBRON-STOCKTON...AND WILL CARRY ISOLATED/SCATTERED SHOWER WORDING FOR JUST A FEW MORE HOURS TO COVER THEM. THIS LINGERING PRECIP IS CLEARLY TIED TO A QUICKLY DEPARTING MID LEVEL CONVERGENCE/FRONTOGENETIC ZONE EVIDENT AT 700MB. GETTING TO THE OFFICIAL NIGHT PERIOD 00Z-12Z...BY THE START OF THE EVENING ANTICIPATE CONSIDERABLE CLEAR SKIES NEARLY CWA-WIDE...AS THE BACK EDGE OF THE PRIMARY MID DECK AND ASSOCIATED SHOWERS/POSSIBLE WEAK STORMS SHOULD BE JUST OFF TO THE SOUTH/EAST OF THE CWA BY THEN. AS A RESULT...HAVE ESSENTIALLY ZERO POPS THROUGH THE NIGHT AREA- WIDE...AS THE TRAILING SOUTHWEST PORTION OF THE POTENT MID LEVEL WAVE CONTINUES EXITING STAGE RIGHT...REACHING AN AXIS FROM NORTHERN WI TO IL BY 12Z. IN ITS WAKE...A PLEASANT AND EVEN SEASONABLY COOL NIGHT WILL SETTLE INTO THE CENTRAL PLAINS. AT THE SURFACE...NORTH BREEZES WILL REALLY LIGHTEN BY SUNSET...AND BECOME NEARLY CALM THROUGH THE NIGHT IN SOME AREAS AS A 1023MB HIGH PRESSURE AXIS CENTERS ITSELF DIRECTLY OVER THE AREA. THE COMBINATION OF THE INVADING DRY AIR...CLEARING SKIES AND LIGHT BREEZES SHOULD SET THE STAGE FOR A RATHER COOL NIGHT BY EARLY AUG STANDARDS. LEANED TOWARD THE LOWER END OF 12Z MET/MAV GUIDANCE FOR LOWS...WHICH RESULTED IN LOWERING PREVIOUS FORECAST BY 2-4 DEGREES MAINLY IN THE FAR NORTHWEST AND SOUTHERN COUNTIES. THEREFORE...AM NOW ADVERTISING LOW-MID 50S ALL AREAS...WITH TYPICAL COOLER SPOTS SUCH AS ORD AND THE PLATTE VALLEY OF WESTERN DAWSON COUNTY VERY POSSIBLY TAGGING UPPER 40S. FOR THIS TIME OF YEAR...DEFINITELY LIGHT JACKET WEATHER FOR THOSE OUT AND ABOUT LATE TONIGHT/EARLY SUNDAY MORNING. FOR THE SUNDAY DAYTIME 12Z-00Z PERIOD...LITERALLY KEPT POPS ZEROED OUT CWA-WIDE...AS A BANNER DAY WITH VERY LITTLE...IF ANY CLOUDS IS FORECAST. IN THE MID-UPPER LEVELS...THE DEPARTING SHORTWAVE WILL REACH ALL THE WAY TO THE EASTERN GREAT LAKES BY LATE AFTERNOON...WHILE THE SOUTHERN CONUS 500MB RIDGE AXIS EXPANDS NORTH AND WEST IN COVERAGE A BIT...BECOMING CENTERED FROM CO/UT TO OK/NORTHERN TX. THIS WILL LEAVE THE CWA IN FAIRLY LIGHT AND VERY DRY WEST-NORTHWEST MID LEVEL FLOW. AT THE SURFACE...THE AFOREMENTIONED RIDGE AXIS WILL START OUT CENTERED OVER THE AREA...BUT GRADUALLY SLIDE EAST TO NEAR THE MO RIVER BY LATE AFTERNOON. AS THE HIGH EDGES EAST...LIGHT SOUTHERLY BREEZES WILL GRADUALLY OVERTAKE MUCH OF THE CWA FROM WEST TO EAST...EVENTUALLY REACHING INTO THE 10-15 MPH RANGE IN FAR WESTERN COUNTIES...BUT REMAINING VERY LIGHT/NEAR CALM ALL DAY IN THE FAR EAST NEAR HWY 81. ALTHOUGH THE LIGHT BREEZES/LACK OF MIXING WILL WORK AGAINST MUCH OF A WARMUP OVER TODAY...PLENTIFUL SUNSHINE AND RELATIVELY DRY AIR WILL WORK IN FAVOR OF IT. AS HAS BEEN THE CASE FOR SEVERAL WEEKS NOW...NUMERICAL GUIDANCE HAS PROVEN DIFFICULT TO EMPLOY...WITH THE MET AVERAGING TOO WARM AND THE MAV TOO COOL. OVERALL THOUGH...WILL LEAN TOWARD THE WARMER END OF GUIDANCE...AND ESSENTIALLY JUST BUMPED UP THE PREVIOUS FORECAST 1 DEGREE. THIS YIELDS NEAR NORMAL HIGHS OF 86-88 MOST AREAS...AND 90-92 IN KS ZONES AND FURNAS COUNTY AREA. LOWERED DEWPOINTS A BIT FROM PREVIOUS FORECAST AS WELL...WITH ONLY MID-UPPER 40S SOUTHWEST AND LOW-MID 50S SOUTHEAST. ALTHOUGH RELATIVE HUMIDITY VALUES COULD DROP CLOSE TO THE 20 PERCENT CRITICAL FIRE WEATHER THRESHOLD IN A FEW FAR SOUTHWEST COUNTIES...WINDS SPEEDS WILL FALL WELL SHORT OF FIRE WEATHER CRITERIA. LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. MODELS NOT IN TOO BAD OF AGREEMENT TO START OFF THE LONG TERM PERIOD...SHOWING SUNDAY EVENING REMAINING UNDER ZONAL/WEAK NORTHWESTERLY FLOW IN THE UPPER LEVELS...A RESULT OF A BROAD HIGH PRESSURE IN PLACE ACROSS THE SCENTRAL/SWRN CONUS AND A TROUGH SHIFTING TOWARD THE EAST COAST. DURING THE OVERNIGHT HOURS...THE FLOW DOES AMPLIFY SOME AS ANOTHER TROUGH IS MAKING ITS WAY TOWARD THE WEST COAST...BUT NO NOTABLE DISTURBANCES LOOK TO MOVE THROUGH AND DECIDED TO KEEP THE FORECAST DRY. HOWEVER...MODELS DO SHOW THE SFC/LOWER LEVEL WINDS REMAINING S/SWRLY OVERNIGHT...WITH INCREASING VALUES OF ELEVATED INSTABILITY SHIFTING NORTH INTO THE REGION AS A STRONGER /30-35KT OR SO/ LLJ DEVELOPS...MAINLY ACROSS THE HIGH PLAINS REGION. THE EDGE OF THIS LLJ/INSTABILITY AXIS DOES LIE OVER THE WRN PORTIONS OF THE CWA...AND MAY HAVE TO KEEP AN EYE ON THIS AREA FOR THE POTENTIAL FOR PERHAPS SOME LIGHT PRECIP /BUT FORECAST SOUNDINGS ARE PRETTY DRY IN THE LOWER LEVELS/...OR A LITTLE MORE IN THE WAY OF CLOUD COVER. INTO MONDAY/MONDAY NIGHT...THE MAIN STORY LIES WITH THE ARRIVAL OF A MID/UPPER LEVEL WAVE...ASSOCIATED WITH A LOW PRESSURE SYSTEM LOCATED UP NEAR THE HUDSON BAY. KEPT THE DAYTIME HOURS ON MONDAY DRY...THOUGH A LITTLE MORE UNCERTAINTY ARISES TOWARD THE LATE AFTERNOON HOURS...WITH THE ACCOMPANYING SURFACE FRONTAL BOUNDARY LOOKS TO BE KNOCKING ON THE DOOR OF THE FAR NW CORNER OF THE CWA. DID RAISE POPS A BIT DURING THE EVENING/OVERNIGHT HOURS ACROSS THE N/NWRN PORTIONS OF THE CWA...BUT DIDNT MAKE MUCH CHANGE FURTHER SOUTH. AHEAD OF THE FRONT ON MONDAY...EXPECTING INCREASED SOUTHERLY WINDS...LIKELY A BIT GUSTY DURING THE AFTERNOON...AND WARMER TEMPERATURES WITH HIGHS FORECAST TO REACH INTO THE MID/UPPER 90S FOR MUCH/IF NOT ALL OF THE CWA. CONDITIONS DURING THE AFTERNOON HOURS SHOULD REMAIN BELOW CRITICAL FIRE LEVELS...RHS COULD DROP INTO THE LOWER/MID 20S ACROSS THE SOUTH...BUT SUSTAINED WIND SPEEDS ARE EXPECTED TO REMAIN <20 MPH...THOUGH GUSTS COULD AT TIMES COME CLOSE TO 25 MPH. WILL BE SOMETHING TO KEEP AN EYE ON IF MODELS HAPPEN TO TREND UP WINDS/TREND DOWN DPS. KEPT SOME LINGERING POPS IN DURING THE DAY ON TUESDAY...MAINLY ACROSS THE SRN HALF OF THE CWA...IN CLOSER PROXIMITY TO WHERE THE SFC BOUNDARY IS EXPECTED TO BE /SOMEWHERE NEAR OR SOUTH OF THE NEB AND KS STATE LINE/. CONFIDENCE NOT THE HIGHEST...AS THE PLACEMENT OF THE FRONT WILL BE DEPENDENT ON HOW THINGS PAN OUT MONDAY NIGHT. WITH MOST OF THE CWA LOOKING TO BE ON THE NORTH SIDE OF THAT BOUNDARY...MORE EASTERLY WINDS EXPECTED TO BE IN PLACE...AND FORECAST HIGHS ARE A TOUCH COOLER THAN MONDAY...MORE IN THE LOWER/MID 90S. BY 00Z WEDNESDAY...THE UPPER LEVEL PATTERN ACROSS THE CONUS HAS BECOME MORE AMPLIFIED...WITH MORE SOLIDLY NORTHWESTERLY FLOW IN PLACE ACROSS THE REGION AS THE RIDGE AXIS EXTENDS FROM THE DESERT SW THROUGH THE ROCKIES AND INTO CANADA. THE NOSE OF AN UPPER LEVEL JET STREAK ROUNDING THE TOP OF THE RIDGE AXIS IS EXPECTED TO SHIFT INTO THE REGION FROM THE NW...BRINGING THE POTENTIAL FOR MORE PRECIPITATION TUESDAY EVENING/OVERNIGHT. SIMILAR TO MONDAY/MONDAY NIGHT...WHILE THERE IS INSTABILITY IN PLACE ACROSS THE REGION...OVERALL DEEP LAYER SHEAR IS CERTAINLY NOT OUTSTANDING...GENERALLY TOPPING OUT IN THE 25-30 KTS RANGE...SO WHILE SOME THUNDERSTORMS COULD BE ON THE STRONGER SIDE...NOT EXPECTING SEVERE WEATHER AT THIS POINT. INTO WEDNESDAY...MODELS CONTINUE TO SHOW THE NOSE OF THIS UPPER LEVEL JET IN THE AREA...AND DECIDED TO KEEP SOME LINGERING POPS IN THE AREA...BUT CONFIDENCE IN CHANCES STICKING AROUND LONGER THAN PERHAPS A FEW HOURS IN THE MORNING NOT EXACTLY HIGH. THAT LOWER CONFIDENCE CONTINUES RIGHT ON THROUGH THE REMAINDER OF THE LONG TERM PERIOD. THE UPPER LEVEL PATTERN REMAINS NORTHWESTERLY ACROSS THE REGION WITH THE RIDGE STAYING IN PLACE OVER THE CENTRAL ROCKIES...AND KEPT THE FORECAST DRY AT THIS POINT...WITH MODELS SHOWING SOME DIFFERENCES WITH DISTURBANCES PASSING TO THE EAST OF THE CWA...AND WHETHER WE SEE ANY PRECIP AS RESULT. WITH THE RIDGE/WARMEST AIR REMAINING OFF TO THE WEST OF THE CWA...AND THE POTENTIAL FOR AN ADDITIONAL FRONTAL PASSAGE...NOTABLY HIGHER TEMPERATURES ARE NOT EXPECTED...WITH FORECAST HIGHS RANGING FROM ROUGHLY THE MID 90S WED/THUR TO THE MID 80S TO LOWER 90S FRI/SAT. PREV DISCUSSION... /ISSUED 1155 AM CDT SAT AUG 4 2012/ CLIMATE...TODAY/TONIGHT WILL LIKELY END UP BEING THE COOLEST DAY/NIGHT AT GRAND ISLAND AND HASTINGS IN 6.5 WEEKS. BASED ON FORECAST PROJECTIONS OVER THE NEXT FEW HOURS...THE CALENDAR DAY HIGH TEMPERATURE AT BOTH GRAND ISLAND AND HASTINGS WILL END UP SOMEWHERE BETWEEN 78-82 DEGREES...BUT IS GUARANTEED TO BE AT LEAST 78 BECAUSE THIS VALUE WAS REACHED SHORTLY AFTER MIDNIGHT BEFORE THE COLD FRONT INVADED. FOR GRAND ISLAND...A HIGH OF 79-82 DEGREES WOULD RESULT IN THE COOLEST DAILY HIGH SINCE JUNE 20TH...WHEN IT TOPPED OUT AT 79. FOR HASTINGS...A HIGH OF 78-79 DEGREES WOULD ALSO RESULT IN THE COOLEST DAY SINCE JUNE 20TH...WHEN IT REACHED 78. TURNING TO LOW TEMPERATURES TONIGHT...THE CURRENT FORECAST FOR BOTH GRAND ISLAND AND HASTINGS CALLS FOR 55. THIS IS ONLY 3 DEGREES ABOVE HASTINGS AUGUST 5TH RECORD LOW OF 52...AND 4 DEGREES ABOVE THE GRAND ISLAND RECORD LOW OF 51...BOTH SET IN 1994. ASSUMING IT DIPS TO AT LEAST 57 DEGREES OVERNIGHT...THIS WILL BE THE COOLEST LOW TEMP IN BOTH CITIES SINCE JUNE 21ST...WHEN GRAND ISLAND BOTTOMED OUT AT 52 AND HASTINGS 51. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION...BRYANT SHORT TERM...PFANNKUCH LONG TERM...ADO
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1159 PM MDT SAT AUG 4 2012 .AVIATION... 06Z TAF CYCLE BACK DOOR FRONT NOW WEST OF THE MID AND LOWER RIO GRANDE VALLEY WITH VARYING STRENGTH NE THROUGH SE WINDS THAT MAY STILL GUST ON OCCASION BETWEEN 25 AND 35 KTS...BUT AVIATION WX WARNING WAS DROPPED FOR THE ABQ SUNPORT AS SPEEDS AT UPPER END OF THAT RANGE AT LEAST PARTIALLY CONVECTIVELY INDUCED. FRONT TO CONTINUE STEADILY SOUTH AND WEST ACROSS SE PLAINS AND TO NEAR CONTINENTAL DIVIDE AREA BY EARLY MORN. CONVECTION WEST OF RIO GRANDE VALLEY MAY INCREASE A BIT POST MIDNIGHT PERIOD DUE TO INFLUENCE OF WESTBOUND FRONT...BUT STRONG STORMS LESS LIKELY THROUGH MORN HOURS. STILL AT LEAST A FEW AREAS OF MVFR CONDITIONS EXPECTED WITH STORMS AND AFTER 08 OR 09Z VCNTY OF E SLOPES OF CENTRAL MTN CHAIN AND E INTO SOME OF ADJACENT HIGHLANDS TO THE E. SHOWERS AND STORMS AGAIN DEVELOPING AFTER ROUGHLY 18Z SUN...BUT FAVORING NW THIRD TO HALF OF FCST AREA. SOME LOCALIZED AREAS MVFR WITH THE STRONGER STORMS...ALONG WITH A FEW INSTANCES OF ASSOCIATED SMALL HAIL AND WIND GUSTS BETWEEN 30 AND 45 KTS. 43 && .PREV DISCUSSION...1038 PM MDT SAT AUG 4 2012... AFTER CONSIDERABLE REVIEW HERE AT THE WFO LATE THIS EVENING WE HAVE DECIDED TO CANCEL THE WIND ADVISORY. SCATTERED TO NUMEROUS SHOWERS AND STORMS OVER THE REGION ARE WREAKING HAVOC ON WIND DIRECTIONS OVER THE RIO GRANDE VALLEY. WINDS ARE NORTHERLY LOS ALAMOS...SANTA FE...LAS VEGAS...BELEN...AND SOCORRO. IN THE PAST 30 MINUTES THE WINDS HAVE BEEN WAFFLING BTWN NORTHEAST AND EAST AT THE SUNPORT WITH SPEEDS BTWN 15 AND 20KTS. WE CANNOT RULE OUT ANOTHER BURST OF SLIGHTLY STRONGER WINDS FROM CONVECTION OVER THE ESTANCIA VALLEY HOWEVER ANY WIDESPREAD ADVISORY WINDS WITHIN THE ZONE ARE NOT LIKELY. THE 23Z HRRR SOLUTION AND 03Z RUC13 ALSO AGREE WINDS WILL LIGHTEN UP AND BECOME MORE NORTHERLY AT THE SUNPORT. GUYER .PREV DISCUSSION...842 PM MDT SAT AUG 4 2012... RAISED POPS OVER THE CENTRAL VALLEY AND SURROUNDING HIGH TERRAIN AS THE FRONTAL BOUNDARY INTERACTS MOVES WEST AND INTERACTS WITH OUTFLOW BOUNDARIES SLIDING EAST FROM A WELL DEFINED COLD POOL ALONG THE CONT DVD. ALSO SHIFTED ZONE OF HIGHEST POPS FARTHER SOUTH OVER THE EASTERN PLAINS WHERE THE FRONT HAS MADE IT ALL THE WAY TO ROSWELL. GUYER .PREV DISCUSSION...632 PM MDT SAT AUG 4 2012... .AVIATION... 00Z TAF CYCLE BACK DOOR COLD FRONT AND ITS EFFECT ON WINDS AND THUNDERSTORM ACTIVITY TO BE MAIN WEATHER STORY FOR TONIGHT. INITIALLY THROUGH ABOUT 03 OR 04Z STRONG TO MARGINALLY SEVERE TSRA WILL BE ONGOING NE OF A LINE FROM SANTA ROSA TO KROW...BUT CHAVES AND ROOSEVELT COUNTY PORTIONS OF THIS AREA WILL SEE BEST CHANCE STRONG STORMS AFTER ABOUT 01Z. SOME INSTANCES OF HAIL TO PENNY OR QUARTER SIZE LIKELY. FRONT WILL ALSO BE THE FOCUS FOR FAIRLY WIDESPREAD CONVECTION FROM CENTRAL MT CHAIN TO PECOS RIVER VALLEY THROUGH THE EVENING. FRONT TO CONTINUE STEADILY SOUTH AND WEST INTO SOUTHEAST PLAINS AND MIDDLE TO LOWER RIO GRANDE VALLEY AREA WITH LATTER AREA EXPERIENCING STRONG E WINDS IN THE 20 TO 30 KT RANGE AND GUSTS BETWEEN 35 AND 45 KTS STARTING BETWEEN 0130Z AND 03Z...CONTINUING UNTIL SOMETIME BETWEEN 08Z AND 11Z BEFORE DIMINISHING SOMEWHAT. THUS AWW LIKELY NEEDED IN ABQ VCNTY FROM MID EVE UNTIL A FEW HOURS PAST MIDNIGHT. CONVECTION WEST OF RIO GRANDE VALLEY LIKELY TO BE MAINLY SCT TO AT TIMES ISOLD. HEAVY RAIN MORE LIKELY NEAR AND ESPECIALLY E OF RIO GRANDE. AREAS OF MVFR CONDITIONS EXPECTED WITH THE STRONGER STORMS AND LATE TONIGHT IN THE E SLOPES OF CENTRAL MTN CHAIN AND E INTO SOME OF ADJACENT HIGHLANDS TO THE E. STORM STRENGTH TO DIMINISH SOME AFTER ABOUT 06 OR 07Z. 43 .PREV DISCUSSION...318 PM MDT SAT AUG 4 2012... BACKDOOR COLD FRONT CURRENTLY LOCATED UP ALONG THE EASTERN SLOPES OF THE SANGRE DE CRISTO MOUNTAINS SOUTH TO MILAGRO...THEN SOUTHEAST TO PORTALES. SCATTERED THUNDERSTORMS FIRING OVER THE EASTERN PEAKS AND SLOPES OF THE SANGRES AND ALONG THE CENTRAL HIGHLANDS SOUTH TO THE SOUTH CENTRAL MTNS. THE FRONT WILL SURGE WESTWARD THIS EVENING...INTO THE CENTRAL VALLEYS. GIVEN LATEST MODEL GUIDANCE AS WELL AS PROGGED PRESSURE DIFFERENCES FROM NORTHEAST TO SOUTHWEST NM INDICATING ADVISORY SPEEDS FOR THE MIDDLE RIO GRANDE VALLEY TONIGHT. AS A RESULT...DECIDED ON WIND ADVISORY FOR THE MIDDLE RIO GRANDE VALLEY...MAINLY DOWNWIND OF TIJERAS CANYON AND FOR THE PLACITAS AREA...ALTHOUGH THE NAM12 SUGGESTING A STRONG SURGE NEAR CREST LEVEL/H7 WHICH WOULD FAVOR THE WESTERN SANDIA MOUNTAIN FOOTHILLS AS WELL. GFS ON THE OTHER HAND NOT NEAR AS DEEP WITH A LIGHT SOUTHERLY WIND AT 700 MB OVERNIGHT. 12Z KDEN SOUNDING WOULD SUGGEST THAT THE NAM MAY BE ON TO SOMETHING AND THAT THE EAST WINDS WILL SPILL OVER THE TOP OF THE SANDIA MOUNTAIN CREST LATE TONIGHT. LOW LEVEL ELY PUSH SHOULD KEEP ISOLATED TO SCT SHOWERS AND STORMS GOING OVERNIGHT WITH THE POTENTIAL FOR LOCALLY HEAVY RAIN FROM CENTRAL MOUNTAINS EAST THIS EVENING. A STRONG STORM OR TWO IS ALSO POSSIBLE ALONG/NEAR THE FRONT GIVEN THE STRONG VERTICAL WIND SHEAR PROFILE...WITH HAIL BEING THE MAIN THREAT. FRONT PUSHES WEST TO THE NM/AZ BORDER BY SUNRISE SUNDAY...SETTING THE STAGE FOR ANOTHER ACTIVE WEATHER DAY. MAIN AREA OF CONVECTION IS EXPECTED NORTHWEST OF A GLENWOOD TO CLAYTON LINE. NAM12 HAS BACKED OFF ON INSTABILITY/LIFTED INDEX VALUES SOMEWHAT FOR SUNDAY AFTERNOON. THE COOLER AIRMASS AND SCATTERED TO BROKEN CLOUD COVER TYPICALLY SPELL A LATE START TO WHAT SHOULD TURN OUT TO BE A VERY ACTIVE LATE AFTERNOON AND EARLY EVENING FOR THE WEST AND NORTHWEST ZONES. DECIDED ON A FLASH FLOOD WATCH FOR THE WESTERN AND NORTHWESTERN MOUNTAINS AND VALLEYS...WITH THE LIKELIHOOD OF BACKDOOR COLD FRONT STALLING NEAR THE CONTINENTAL DIVIDE SUNDAY MORNING...SETTING UP STRONG SURFACE CONVERGENCE TO EASILY GET NUMEROUS STORMS GOING. WEAK STEERING LEVEL FLOW OF AROUND 10 KTS AND RECENT HEAVY RAINS OVER WRN AND NWRN NM WILL MAKE THIS AREA MORE PRONE TO LOCALIZED FLASH FLOODING SUNDAY AFTERNOON AND EVENING. ELSEWHERE...FLASH FLOODING REMAINS A CONCERN DUE TO THE WEEK FLOW AND PRECIPITABLE WATER VALUES OF OVER ONE INCH...BUT TOUGH TO PICK OUT ANY PARTICULAR AREA OUTSIDE OF A BURN SCAR THAT MAY HAVE AN ELEVATED RISK DUE TO METEOROLOGICAL FACTORS. LATER SHIFTS MAY NEED EXPAND THE FLASH FLOOD WATCH FARTHER EAST IF APPARENT SFC BOUNDARIES SET UP FROM TODAY`S ROUND OF CONVECTION. CENTER OF THE UPPER LEVEL HIGH EARNS ITS NAME DURING THE COMING WEEK. THE HIGH MOVES TO JUST WEST OF THE FOUR CORNERS MONDAY AND REMAINS NEARLY STATIONARY THROUGH THE REMAINDER OF THE WEEK. PLENTY OF RESIDUAL MOISTURE EXPECTED TO FIRE UP ROUNDS OF MAINLY MOUNTAIN CONVECTION EACH AFTERNOON...WITH THE POTENTIAL OF ISOLATED STORMS MOVING OUT OVER LOWER ELEVATIONS IN A SOUTHEAST DIRECTION MONDAY...DUE SOUTH TUESDAY...THEN SOUTHWEST OR WEST MID- WEEK. 33 .FIRE WEATHER... BACK DOOR COLD FRONT PLUNGING SOUTH AND WESTWARD ACROSS PORTIONS OF THE FORECAST AREA TODAY. MAIN BOUNDARY EXTENDS FROM NEAR PORTALES UP TO SANTA ROSA AND ABUTTING UP TO THE EAST SLOPES OF THE SANGRES. THIS FRONT WILL DRIVE FURTHER SOUTH AND WEST REST OF TODAY INTO TONIGHT. LOOKING AT SOME GUSTIER GAP WINDS ALONG THE CENTRAL MOUNTAIN CHAIN WITH GUSTS BETWEEN 40 TO POSSIBLY EVEN 50 MPH NEAR THE TIJERAS/ALBUQUERQUE GAP. LESS MOISTURE TO WORK WITH IN THE WEST...ESPECIALLY NORTHWEST WITH MORE ABUNDANT MOISTURE CENTRAL MOUNTAINS EASTWARD. THUS...WETTING RAIN WILL BE MORE PREVALENT THERE. DUE TO THE FRONTAL PUSH...THE BEST DYNAMICS COMBINED WITH MOISTURE WILL SHIFT WESTWARD ON SUNDAY. LOOK FOR WETTING RAINFALL ALONG THE CONTINENTAL DIVIDE TO THE CENTRAL MOUNTAINS FAVORING THE NORTH CENTRAL MOUNTAINS AND NORTHWEST THIRD OF THE AREA. UPPER HIGH WILL BE CENTERED OVER NORTH CENTRAL TEXAS. THE MODELS STILL POINT TOWARDS AN UPPER HIGH MIGRATION EASTWARD TO OVER OR NEAR THE FOUR CORNERS REGION THE EARLIER HALF OF NEXT WEEK. RECYCLING IN THE FORM IF ISOLATED TO SCATTERED THUNDERSTORMS IS EXPECTED MONDAY AND TUESDAY. TEMPERATURES WILL ALSO BE ON THE WARMER SIDE. HUMIDITIES COULD FALL INTO THE TEENS FOR A SHORT WHILE ACROSS THE FOUR CORNERS REGION AS WELL AS LOWER/MID RIO GRANDE VALLEY AND EASTERN PLAINS DURING THIS PERIOD. DEPENDING ON THE POSITION OF THE UPPER HIGH AND PERHAPS SOME SORT OF BACK DOOR INFLUENCE...WEDNESDAY COULD SEE AN UPTICK IN STORM COVERAGE. RIGHT NOW...THE MODELS INFLUENCE SOUTHERN AND EASTERN AREAS AND THE LATEST GFS IS MORE BULLISH THAN THE ECMWF. SO WILL HAVE TO SEE ON THAT. MODELS GET DRIER THURSDAY/FRIDAY OF NEXT WEEK AS THE UPPER HIGH REMAINS OVER SOME PORTION OF THE FOUR CORNERS AREA. AT THE SAME TIME A MID LEVEL DRY SLOT OR DRY INTRUSION SHOULD MAKE ITS WAY IN FROM OVER THE HIGH PLAINS AND START TO REDUCE THUNDERSTORM DEVELOPMENT ACCORDINGLY. TEMPERATURES WOULD MOST LIKELY REMAIN ABOVE NORMAL. 50 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES...NMZ501>507-510-511-517. && $$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1038 PM MDT SAT AUG 4 2012 .UPDATE... AFTER CONSIDERABLE REVIEW HERE AT THE WFO LATE THIS EVENING WE HAVE DECIDED TO CANCEL THE WIND ADVISORY. SCATTERED TO NUMEROUS SHOWERS AND STORMS OVER THE REGION ARE WREAKING HAVOC ON WIND DIRECTIONS OVER THE RIO GRANDE VALLEY. WINDS ARE NORTHERLY LOS ALAMOS...SANTA FE...LAS VEGAS...BELEN...AND SOCORRO. IN THE PAST 30 MINUTES THE WINDS HAVE BEEN WAFFLING BTWN NORTHEAST AND EAST AT THE SUNPORT WITH SPEEDS BTWN 15 AND 20KTS. WE CANNOT RULE OUT ANOTHER BURST OF SLIGHTLY STRONGER WINDS FROM CONVECTION OVER THE ESTANCIA VALLEY HOWEVER ANY WIDESPREAD ADVISORY WINDS WITHIN THE ZONE ARE NOT LIKELY. THE 23Z HRRR SOLUTION AND 03Z RUC13 ALSO AGREE WINDS WILL LIGHTEN UP AND BECOME MORE NORTHERLY AT THE SUNPORT. GUYER && .PREV DISCUSSION...842 PM MDT SAT AUG 4 2012... RAISED POPS OVER THE CENTRAL VALLEY AND SURROUNDING HIGH TERRAIN AS THE FRONTAL BOUNDARY INTERACTS MOVES WEST AND INTERACTS WITH OUTFLOW BOUNDARIES SLIDING EAST FROM A WELL DEFINED COLD POOL ALONG THE CONT DVD. ALSO SHIFTED ZONE OF HIGHEST POPS FARTHER SOUTH OVER THE EASTERN PLAINS WHERE THE FRONT HAS MADE IT ALL THE WAY TO ROSWELL. GUYER .PREV DISCUSSION...632 PM MDT SAT AUG 4 2012... .AVIATION... 00Z TAF CYCLE BACK DOOR COLD FRONT AND ITS EFFECT ON WINDS AND THUNDERSTORM ACTIVITY TO BE MAIN WEATHER STORY FOR TONIGHT. INITIALLY THROUGH ABOUT 03 OR 04Z STRONG TO MARGINALLY SEVERE TSRA WILL BE ONGOING NE OF A LINE FROM SANTA ROSA TO KROW...BUT CHAVES AND ROOSEVELT COUNTY PORTIONS OF THIS AREA WILL SEE BEST CHANCE STRONG STORMS AFTER ABOUT 01Z. SOME INSTANCES OF HAIL TO PENNY OR QUARTER SIZE LIKELY. FRONT WILL ALSO BE THE FOCUS FOR FAIRLY WIDESPREAD CONVECTION FROM CENTRAL MT CHAIN TO PECOS RIVER VALLEY THROUGH THE EVENING. FRONT TO CONTINUE STEADILY SOUTH AND WEST INTO SOUTHEAST PLAINS AND MIDDLE TO LOWER RIO GRANDE VALLEY AREA WITH LATTER AREA EXPERIENCING STRONG E WINDS IN THE 20 TO 30 KT RANGE AND GUSTS BETWEEN 35 AND 45 KTS STARTING BETWEEN 0130Z AND 03Z...CONTINUING UNTIL SOMETIME BETWEEN 08Z AND 11Z BEFORE DIMINISHING SOMEWHAT. THUS AWW LIKELY NEEDED IN ABQ VCNTY FROM MID EVE UNTIL A FEW HOURS PAST MIDNIGHT. CONVECTION WEST OF RIO GRANDE VALLEY LIKELY TO BE MAINLY SCT TO AT TIMES ISOLD. HEAVY RAIN MORE LIKELY NEAR AND ESPECIALLY E OF RIO GRANDE. AREAS OF MVFR CONDITIONS EXPECTED WITH THE STRONGER STORMS AND LATE TONIGHT IN THE E SLOPES OF CENTRAL MTN CHAIN AND E INTO SOME OF ADJACENT HIGHLANDS TO THE E. STORM STRENGTH TO DIMINISH SOME AFTER ABOUT 06 OR 07Z. 43 .PREV DISCUSSION...318 PM MDT SAT AUG 4 2012... BACKDOOR COLD FRONT CURRENTLY LOCATED UP ALONG THE EASTERN SLOPES OF THE SANGRE DE CRISTO MOUNTAINS SOUTH TO MILAGRO...THEN SOUTHEAST TO PORTALES. SCATTERED THUNDERSTORMS FIRING OVER THE EASTERN PEAKS AND SLOPES OF THE SANGRES AND ALONG THE CENTRAL HIGHLANDS SOUTH TO THE SOUTH CENTRAL MTNS. THE FRONT WILL SURGE WESTWARD THIS EVENING...INTO THE CENTRAL VALLEYS. GIVEN LATEST MODEL GUIDANCE AS WELL AS PROGGED PRESSURE DIFFERENCES FROM NORTHEAST TO SOUTHWEST NM INDICATING ADVISORY SPEEDS FOR THE MIDDLE RIO GRANDE VALLEY TONIGHT. AS A RESULT...DECIDED ON WIND ADVISORY FOR THE MIDDLE RIO GRANDE VALLEY...MAINLY DOWNWIND OF TIJERAS CANYON AND FOR THE PLACITAS AREA...ALTHOUGH THE NAM12 SUGGESTING A STRONG SURGE NEAR CREST LEVEL/H7 WHICH WOULD FAVOR THE WESTERN SANDIA MOUNTAIN FOOTHILLS AS WELL. GFS ON THE OTHER HAND NOT NEAR AS DEEP WITH A LIGHT SOUTHERLY WIND AT 700 MB OVERNIGHT. 12Z KDEN SOUNDING WOULD SUGGEST THAT THE NAM MAY BE ON TO SOMETHING AND THAT THE EAST WINDS WILL SPILL OVER THE TOP OF THE SANDIA MOUNTAIN CREST LATE TONIGHT. LOW LEVEL ELY PUSH SHOULD KEEP ISOLATED TO SCT SHOWERS AND STORMS GOING OVERNIGHT WITH THE POTENTIAL FOR LOCALLY HEAVY RAIN FROM CENTRAL MOUNTAINS EAST THIS EVENING. A STRONG STORM OR TWO IS ALSO POSSIBLE ALONG/NEAR THE FRONT GIVEN THE STRONG VERTICAL WIND SHEAR PROFILE...WITH HAIL BEING THE MAIN THREAT. FRONT PUSHES WEST TO THE NM/AZ BORDER BY SUNRISE SUNDAY...SETTING THE STAGE FOR ANOTHER ACTIVE WEATHER DAY. MAIN AREA OF CONVECTION IS EXPECTED NORTHWEST OF A GLENWOOD TO CLAYTON LINE. NAM12 HAS BACKED OFF ON INSTABILITY/LIFTED INDEX VALUES SOMEWHAT FOR SUNDAY AFTERNOON. THE COOLER AIRMASS AND SCATTERED TO BROKEN CLOUD COVER TYPICALLY SPELL A LATE START TO WHAT SHOULD TURN OUT TO BE A VERY ACTIVE LATE AFTERNOON AND EARLY EVENING FOR THE WEST AND NORTHWEST ZONES. DECIDED ON A FLASH FLOOD WATCH FOR THE WESTERN AND NORTHWESTERN MOUNTAINS AND VALLEYS...WITH THE LIKELIHOOD OF BACKDOOR COLD FRONT STALLING NEAR THE CONTINENTAL DIVIDE SUNDAY MORNING...SETTING UP STRONG SURFACE CONVERGENCE TO EASILY GET NUMEROUS STORMS GOING. WEAK STEERING LEVEL FLOW OF AROUND 10 KTS AND RECENT HEAVY RAINS OVER WRN AND NWRN NM WILL MAKE THIS AREA MORE PRONE TO LOCALIZED FLASH FLOODING SUNDAY AFTERNOON AND EVENING. ELSEWHERE...FLASH FLOODING REMAINS A CONCERN DUE TO THE WEEK FLOW AND PRECIPITABLE WATER VALUES OF OVER ONE INCH...BUT TOUGH TO PICK OUT ANY PARTICULAR AREA OUTSIDE OF A BURN SCAR THAT MAY HAVE AN ELEVATED RISK DUE TO METEOROLOGICAL FACTORS. LATER SHIFTS MAY NEED EXPAND THE FLASH FLOOD WATCH FARTHER EAST IF APPARENT SFC BOUNDARIES SET UP FROM TODAY`S ROUND OF CONVECTION. CENTER OF THE UPPER LEVEL HIGH EARNS ITS NAME DURING THE COMING WEEK. THE HIGH MOVES TO JUST WEST OF THE FOUR CORNERS MONDAY AND REMAINS NEARLY STATIONARY THROUGH THE REMAINDER OF THE WEEK. PLENTY OF RESIDUAL MOISTURE EXPECTED TO FIRE UP ROUNDS OF MAINLY MOUNTAIN CONVECTION EACH AFTERNOON...WITH THE POTENTIAL OF ISOLATED STORMS MOVING OUT OVER LOWER ELEVATIONS IN A SOUTHEAST DIRECTION MONDAY...DUE SOUTH TUESDAY...THEN SOUTHWEST OR WEST MID- WEEK. 33 .FIRE WEATHER... BACK DOOR COLD FRONT PLUNGING SOUTH AND WESTWARD ACROSS PORTIONS OF THE FORECAST AREA TODAY. MAIN BOUNDARY EXTENDS FROM NEAR PORTALES UP TO SANTA ROSA AND ABUTTING UP TO THE EAST SLOPES OF THE SANGRES. THIS FRONT WILL DRIVE FURTHER SOUTH AND WEST REST OF TODAY INTO TONIGHT. LOOKING AT SOME GUSTIER GAP WINDS ALONG THE CENTRAL MOUNTAIN CHAIN WITH GUSTS BETWEEN 40 TO POSSIBLY EVEN 50 MPH NEAR THE TIJERAS/ALBUQUERQUE GAP. LESS MOISTURE TO WORK WITH IN THE WEST...ESPECIALLY NORTHWEST WITH MORE ABUNDANT MOISTURE CENTRAL MOUNTAINS EASTWARD. THUS...WETTING RAIN WILL BE MORE PREVALENT THERE. DUE TO THE FRONTAL PUSH...THE BEST DYNAMICS COMBINED WITH MOISTURE WILL SHIFT WESTWARD ON SUNDAY. LOOK FOR WETTING RAINFALL ALONG THE CONTINENTAL DIVIDE TO THE CENTRAL MOUNTAINS FAVORING THE NORTH CENTRAL MOUNTAINS AND NORTHWEST THIRD OF THE AREA. UPPER HIGH WILL BE CENTERED OVER NORTH CENTRAL TEXAS. THE MODELS STILL POINT TOWARDS AN UPPER HIGH MIGRATION EASTWARD TO OVER OR NEAR THE FOUR CORNERS REGION THE EARLIER HALF OF NEXT WEEK. RECYCLING IN THE FORM IF ISOLATED TO SCATTERED THUNDERSTORMS IS EXPECTED MONDAY AND TUESDAY. TEMPERATURES WILL ALSO BE ON THE WARMER SIDE. HUMIDITIES COULD FALL INTO THE TEENS FOR A SHORT WHILE ACROSS THE FOUR CORNERS REGION AS WELL AS LOWER/MID RIO GRANDE VALLEY AND EASTERN PLAINS DURING THIS PERIOD. DEPENDING ON THE POSITION OF THE UPPER HIGH AND PERHAPS SOME SORT OF BACK DOOR INFLUENCE...WEDNESDAY COULD SEE AN UPTICK IN STORM COVERAGE. RIGHT NOW...THE MODELS INFLUENCE SOUTHERN AND EASTERN AREAS AND THE LATEST GFS IS MORE BULLISH THAN THE ECMWF. SO WILL HAVE TO SEE ON THAT. MODELS GET DRIER THURSDAY/FRIDAY OF NEXT WEEK AS THE UPPER HIGH REMAINS OVER SOME PORTION OF THE FOUR CORNERS AREA. AT THE SAME TIME A MID LEVEL DRY SLOT OR DRY INTRUSION SHOULD MAKE ITS WAY IN FROM OVER THE HIGH PLAINS AND START TO REDUCE THUNDERSTORM DEVELOPMENT ACCORDINGLY. TEMPERATURES WOULD MOST LIKELY REMAIN ABOVE NORMAL. 50 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES...NMZ501>507-510-511-517. && $$ GUYER
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
346 AM EDT SUN AUG 5 2012 .SYNOPSIS... WEAK HIGH PRESSURE WILL CONTINUE OVER THE REGION TODAY. A COLD FRONT WILL STALL NORTH AND WEST OF THE AREA MONDAY AND TUESDAY BEFORE MOVING INTO THE REGION WEDNESDAY. THE FRONT WILL DISSIPATE BY LATE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 330 AM SUNDAY...PATCHY LIGHT SHOWERS HAVE DEVELOPED OVER THE CENTRAL COASTAL SECTIONS AND INLAND OVER THE NORTHERN COASTAL PLAINS REGION THIS MORNING IN A NICE MID-LEVEL DEFORMATION ZONE. THE RAP MODEL SHOWS ADDITIONAL SHOWERS APPROACHING THE COASTAL COUNTIES AFTER SUNRISE BUT WITH LESS COVERAGE THAN ON SATURDAY. ISOLATED SHOWERS/TSTMS MAY FORM ALONG THE SEA BREEZE DURING THE AFTERNOON. HAVE INDICATED THE POPS GENERALLY EAST OF HIGHWAY 17 THIS MORNING...THEN SHIFTING INLAND AFTER NOON. TEMPERATURES SHOULD BE SIMILAR TO YESTERDAY WITH MAXES IN THE UPPER 80S TO AROUND 90 DEGREES. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... AS OF 335 AM SUNDAY...ONCE AGAIN TONIGHT...SOME WEAK MID-LEVEL VORTICITY WILL ROTATE ALONG THE OUTER PERIPHERY OF THE BUILDING RIDGE CREATING A LEAST A FEW WIDELY SCATTERED SHOWERS OR TSTMS ALONG THE SOUTHERN COASTAL COUNTIES TOWARD MORNING. LITTLE CHANGE IN TEMPERATURE IS EXPECTED FROM PREVIOUS MORNINGS WITH LOWS IN THE 72 TO 78 DEGREE RANGE. && .LONG TERM /MONDAY THROUGH SATURDAY/... AS OF 330 AM SUNDAY...LONG TERM MODELS STILL IN GOOD AGREEMENT ON SYNOPTIC REGIME...WITH WET AND UNSETTLED WEATHER PATTERN SETTING UP FOR E NC. SHORT WAVE TROUGH WILL BYPASS THE AREA TO THE NORTH ON TUE...WITH TRAILING SFC COLD FRONT PUSHING TOWARDS E NC MON NIGHT AND STALLING OVER THE AREA THROUGH AT LEAST MID WEEK. BERMUDA HIGH WILL REMAIN ANCHORED OVER THE SW ATLANTIC BASIN...WHILE BROAD TROUGHING DEVELOPS OVER THE EAST CENTRAL CONUS. THIS WILL PUT THE AREA UNDER HUMID AND MOIST SW FLOW...AND WITH STALLED FRONT OVERHEAD PERIODS OF RAIN AND THUNDERSTORMS WILL PLAGUE E NC BEGINNING LATE MONDAY AND LASTING THROUGH THE WEEK. RAISED POPS TO LIKELY ON TUE AFTERNOON AS GOOD AGREEMENT AMONGST MODEL SUITES DEVELOPING WIDESPREAD THUNDERSHOWERS OVER THE AREA. KEPT HIGH CHANCE WED THROUGH THE END OF THE WEEK AS MESOSCALE DETAILS NEED TO BE WORKED OUT...THOUGH IT APPEARS A GOOD SHOT OF RAIN WILL PERSIST. CHANCES FOR SEVERE APPEAR MARGINAL ATTM ON TUE AS SHEAR WILL BE MEAGER...THOUGH PWATS WILL BE HIGH AND WILL HAVE TO MONITOR POTENTIAL FOR MINOR FLOODING OF TYPICAL FLOOD PRONE AREAS. && .AVIATION /08Z SUNDAY THROUGH SUNDAY NIGHT/... /SHORT TERM TODAY AND TONIGHT/... AS OF 1 AM SUN...NUMERICAL GUIDANCE AGAIN SHOWS SOME MVFR FOG AND POSSIBLE STRATUS DEVELOPING OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN A DEEP SOUTHERLY FLOW AND VERY MOIST BOUNDARY LAYER. ANY FOG SHOULD DISSIPATE BY 12 OR 13Z. WDLY SCT TO SCT CONVECTION AGAIN LIKELY SUN AFTN INLAND WITH BRIEF REDUCTIONS IN CIGS/VSBYS POSS. /LONG TERM MONDAY THROUGH SATURDAY/... AS OF 330 AM SUNDAY...MAINLY VFR CONDITIONS WILL PREVAIL...THOUGH AS IS THE CASE MOST EVENINGS...SOME REDUCTIONS TO MVFR/IFR POSSIBLE LATE AS RADIATION FOG/LOW STRATUS DEVELOPS...ESP IN AREAS THAT RECEIVE RAINFALL. SCT TO NUMEROUS THUNDERSHOWERS WILL PLAGUE THE AREA OFF AND ON LATE MONDAY THROUGH MUCH OF THE WEEK. SOME REDUCTIONS IN VSBY WITH ANY OF THE HEAVIER THUNDERSHOWERS...AS WELL AS SOME GUSTY WINDS. && .MARINE... /SHORT TERM TODAY AND TONIGHT/... AS OF 335 AM SUNDAY...SAME STORY DIFFERENT DAY WITH REGARDS TO THE MARINE FORECAST AS LIGHT S/SSW FLOW CONTINUES. WINDS MAY OCCASIONAL GUST TO NEAR 15 KNOTS...ESPECIALLY NEAR SHOWERS...BUT WILL GENERALLY RUN AT 10 KNOTS OR LESS. LATEST WAVEWATCH 4 AND LOCAL SWAN STILL SHOWING ONLY 1 TO 3 FOOT SEAS WITH A MINIMAL 7 TO 8 SECOND SWELL COMPONENT THROUGH TONIGHT. /LONG TERM MONDAY THROUGH SATURDAY/... AS OF 330 AM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE LONG TERM...THOUGH REMAIN SUB SCA THROUGH THUR. SEAS WILL REMAIN IN THE 3 TO OCNL 4 FT RANGE ACROSS OUTER WATERS WITH 2 TO 3 FEET NEARSHORE. THERE WILL BE CHANCES FOR THUNDERSHOWERS THROUGH THE COMING WEEK AS A COOL FRONT AND TROUGH SAGS INTO CENTRAL AND EASTERN NC AND STALLS OUT. WINDS LOOK TO INC LATE THUR THROUGH SAT AS LOW PRES ACROSS THE GREAT LAKES COMBINED WITH BERMUDA HIGH TO THE SE ACT TO STRENGTHEN THE GRADIENT. SEAS WILL INC TO 6 FT IN RESPONSE ACROSS SOUTHERN/CENTRAL WATERS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...TL AVIATION...CTC/TL MARINE...CTC/TL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
248 AM EDT SUN AUG 5 2012 .SYNOPSIS... A RATHER ACTIVE WEEK CAN BE EXPECTED AS A SERIES OF COLD FRONTS MOVE CLOSER TO THE REGION. THE BEST CHANCE OF RAIN OCCURS ON TUESDAY AND AGAIN FRIDAY AND SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...SCATTERED SHOWER ACTIVITY IS DISSIPATING AS EXPECTED AS IT MOVES INLAND OVER A COOLER AND MORE STABLE NOCTURNAL BOUNDARY LAYER. ADDITIONAL ISOLATED SHOWERS ARE STILL POSSIBLE OVERNIGHT...ALTHOUGH THE LAST TWO HRRR MODEL RUNS SHOW LESS AND LESS COVERAGE AS THE NIGHT PROGRESSES. TEMPERATURES AND DEWPOINTS ARE ON-TRACK AND NO SIGNIFICANT CHANGES ARE NEEDED WITH THIS UPDATE. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... MOIST ONSHORE FLOW WILL CONTINUE THROUGH THE NIGHT WITH 2.0+ INCH PRECIPITABLE WATER VALUES STREAMING IN. THE ATMOSPHERE WILL REMAIN CONVECTIVELY UNSTABLE FOR PARCELS ORIGINATING OFFSHORE WHERE SURFACE AIR TEMPERATURES WILL REMAIN IN THE LOWER 80S WITH MID 70S DEWPOINTS OVERNIGHT. WE WILL THEREFORE MAINTAIN SMALL POPS WITHIN 20 MILES OF THE BEACHES FOR ISOLATED SHOWERS BRUSHING BY. SOME OF THESE ARE ALREADY MOVING ONSHORE IN THE MYRTLE BEACH VICINITY AT THE TIME OF THIS WRITING. SKIES SHOULD AVERAGE MOSTLY CLEAR TO PARTLY CLOUDY. WITH A TROPICAL AIRMASS LOW TEMPERATURES SHOULD ONLY FALL INTO THE LOWER 70S INLAND AND MID 70S AT THE COAST. BEACHES WILL FALL TO THE UPPER 70S TO NEAR 80 DEGREES WITH ONSHORE BREEZES. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... AS OF 3:00 AM SUNDAY...BIG STORY WILL BE THE INCREASE OF POPS MONDAY AND ESPECIALLY TUESDAY VIA HEIGHT FALLS ACCOMPANIED BY A FRONT AT THE SURFACE. MOST OF THE ACTIVITY WILL BE CONCENTRATED INLAND MONDAY. TUESDAY OFFERS MORE WIDESPREAD COVERAGE WITH THE COAST INCLUDED AS A 200MB JET ROTATES ACROSS THE AREA. POPS INCREASE INCREMENTALLY TUESDAY AFTERNOON BUT REMAIN IN THE GOOD CHANCE RANGE OVERALL. SPC HAS THE AREA IN A SEE TEXT FOR MONDAY WITH THE WORDING THAT THE OUTLOOK MAY NEED TO BE ELEVATED TO A SLIGHT RISK. TEMPERATURE GUIDANCE REMAINS CONSISTENT AS DOES THE OFFICIAL FORECAST WHICH LEANS HEAVILY TOWARD THE WARMER MAV NUMBERS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3:00 AM SUNDAY...MEDIUM RANGE GUIDANCE CONTINUES TO SHOW SUBTLE MID LEVEL TROUGHING ACROSS THE EASTERN U.S. THROUGH THE PERIOD. AT THE SURFACE DISSIPATING FRONTAL BOUNDARY WILL MEANDER ACROSS THE AREA WEDNESDAY WITH ANOTHER FRONT MOVING TO JUST NORTH OF THE AREA BY LATE IN THE PERIOD TRAILING ANOTHER STRONG SHORTWAVE MOVING ACROSS THE GREAT LAKES. POPS REMAIN HIGHEST CENTERED AROUND THE STRONGEST FORCING MECHANISMS...WEDNESDAY WITH THE DECAYING FRONT AND THE WEEKEND WITH THE SECOND SYSTEM. LATEST MEX GUIDANCE CONTINUES TO TREND JUST BELOW CLIMATOLOGY AND NUDGED A COUPLE OF PERIODS (LATE) TO FOLLOW THIS TREND. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... AS OF 06Z...VFR EXPECTED THROUGH MUCH OF THE VALID PERIOD. TWO EXCEPTIONS...POTENTIAL PATCHY/LIGHT FOG AND LOW CEILINGS FOR THE EARLY MORNING HOURS MAINLY ACROSS INLAND TERMINALS...AND THE THREAT FOR CONVECTION LATE THIS MORNING FOR COASTAL TERMINALS...AND THIS AFTERNOON FOR INLAND TERMINALS. TROPICAL ATMOSPHERE HAS TAKEN OVER THE FA. WILL OCCASIONALLY OBSERVE ONSHORE MOVEMENT OF MODERATE/TOWERING CU EARLY THIS MORNING. HAVE INDICATED VCSH FOR THE 2 MYRTLES FROM THIS ONSHORE MOVEMENT. FOR THE INLAND TERMINALS...COULD SEE A BRIEF PERIOD OF LOW CEILINGS AND BR LEADING UP TO SUNRISE. AFTER DAYBREAK...ANY LINGERING FOG AND LOW CEILINGS WILL QUICKLY DISSIPATE ALLOWING FOR VFR TO PREVAIL. WITH A VERY TROPICAL AIRMASS IN PLACE AND DEEP SE-S FLOW THRU THE ATM COLUMN...ANTICIPATE MODERATE AND TOWERING CU TO DEVELOP AND/OR MOVE ONSHORE THROUGHOUT THE DAY. LOOK FOR AN INCREASED POTENTIAL FOR MID TO LATE MORNING CONVECTION AT THE COAST...MIGRATING TO INLAND TERMINALS THIS AFTERNOON...WITH THE AID OF THE RESULTANT WIND BOUNDARY/SEABREEZE. SE TO S WINDS WILL PREVAIL WITH 5 TO 10 KT INLAND TERMINALS...5 TO 15 KT FOR THE COASTAL TERMS. FOR THE EVENING HOURS...ANY LINGERING CONVECTION/SHRA SHOULD QUICKLY DISSIPATE AROUND SUNSET. FOR THE MYR TAF...WILL NOT INCLUDE VIS AMEND IN THE LAST LINE. REASON...NO OVERNIGHT VSBY BEING REPORTED IN THE MYR METAR...WHICH HAS BEEN OCCURRING FOR SEVERAL DAYS NOW. EXTENDED OUTLOOK...DAILY CHANCE OF MORNING MVFR/IFR VSBYS AND LOW CEILINGS FROM BR/FG...AND DAILY THREAT FOR DIURNALLY DRIVEN CONVECTION EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...WIND AND SEA OBSERVATIONS ARE SUPPORTED BY THE CURRENT FORECAST AND NO UPDATES ARE NEEDED. RADAR SHOWS SHOWER ACTIVITY BECOMING MORE ISOLATED IN NATURE CURRENTLY...AND THE LATEST COUPLE OF HRRR MODEL RUNS SHOW VERY FEW SHOWERS REMAINING AFTER MIDNIGHT. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... SOUTH-SOUTHEAST WINDS 10-15 KT WILL CONTINUE OVERNIGHT AS WEAK LOW PRESSURE PUSHES ONTO THE FLORIDA EAST COAST. THIS SAME FLOW HAS ENOUGH VERTICAL EXTENT TO PUSH SCATTERED SHOWERS NORTH-NORTHWESTWARD ACROSS THE COASTAL WATERS. LATEST HIGH-RESOLUTION MODELS SHOW THE BEST COVERAGE FOR THESE SCATTERED SHOWERS SHOULD BE THIS EVENING WITH A LITTLE LESS COVERAGE AFTER MIDNIGHT. SEAS SHOULD AVERAGE 2-3 FT WITH SPECTRAL WAVE PLOTS SHOWING PEAKS IN POWER AT AROUND 6 AND 8 SECOND PERIODS. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3:00 AM SUNDAY...SOUTHWEST FLOW OF 10-15 KNOTS WILL PREVAIL ACROSS THE WATERS THROUGH THE PERIOD. STRONGEST WINDS...RELATIVELY SPEAKING WILL OCCUR LATE MONDAY INTO TUESDAY MORNING WHEN THE LOW LEVEL JETTING IS MAXIMIZED. SEAS OF 2-4 FEET. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3:00 AM SUNDAY...THE ONLY DEVIATION FROM THE SUMMER PATTERN OF SOUTHWEST WINDS OF 10-15 KNOTS IS THE POSSIBILITY OF A FRONT BRIEFLY SLIDING THROUGH THE WATERS EARLY THURSDAY WHEN WINDS MAY BRIEFLY TURN TO NORTHWEST. DAYTIME HEATING AND THE QUICK DEVELOPMENT OF THE SEA BREEZE AND PIEDMONT TROUGH WILL TURN WINDS BACK FROM THE SOUTHWEST. WAVEWATCH SEAS CONTINUE IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...TRA SHORT TERM...SHK LONG TERM...SHK AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1225 AM EDT SUN AUG 5 2012 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL BRING TYPICAL SUMMER-TIME WEATHER THROUGH THE WEEKEND...WITH NEAR NORMAL TEMPERATURES AND ISOLATED TO SCATTERED THUNDERSTORMS. A WEAK TROPICAL WAVE MOVING INTO FLORIDA COULD BRING COASTAL SHOWERS SUNDAY AND MONDAY. TROPICAL MOISTURE FROM THE GULF OF MEXICO WILL BRING HUMID AND SOMEWHAT UNSETTLED CONDITIONS TO THE AREA MUCH OF NEXT WEEK...WITH A CHANCE OF RAINFALL EACH DAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...SCATTERED SHOWER ACTIVITY IS DISSIPATING AS EXPECTED AS IT MOVES INLAND OVER A COOLER AND MORE STABLE NOCTURNAL BOUNDARY LAYER. ADDITIONAL ISOLATED SHOWERS ARE STILL POSSIBLE OVERNIGHT...ALTHOUGH THE LAST TWO HRRR MODEL RUNS SHOW LESS AND LESS COVERAGE AS THE NIGHT PROGRESSES. TEMPERATURES AND DEWPOINTS ARE ON-TRACK AND NO SIGNIFICANT CHANGES ARE NEEDED WITH THIS UPDATE. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... MOIST ONSHORE FLOW WILL CONTINUE THROUGH THE NIGHT WITH 2.0+ INCH PRECIPITABLE WATER VALUES STREAMING IN. THE ATMOSPHERE WILL REMAIN CONVECTIVELY UNSTABLE FOR PARCELS ORIGINATING OFFSHORE WHERE SURFACE AIR TEMPERATURES WILL REMAIN IN THE LOWER 80S WITH MID 70S DEWPOINTS OVERNIGHT. WE WILL THEREFORE MAINTAIN SMALL POPS WITHIN 20 MILES OF THE BEACHES FOR ISOLATED SHOWERS BRUSHING BY. SOME OF THESE ARE ALREADY MOVING ONSHORE IN THE MYRTLE BEACH VICINITY AT THE TIME OF THIS WRITING. SKIES SHOULD AVERAGE MOSTLY CLEAR TO PARTLY CLOUDY. WITH A TROPICAL AIRMASS LOW TEMPERATURES SHOULD ONLY FALL INTO THE LOWER 70S INLAND AND MID 70S AT THE COAST. BEACHES WILL FALL TO THE UPPER 70S TO NEAR 80 DEGREES WITH ONSHORE BREEZES. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...OUR AIR MASS BEGINS TO MOISTEN UP SUNDAY THEN ESPECIALLY MONDAY AS A TROPICAL WAVE MOVES INLAND ACROSS FLORIDA...AND PREVAILING DEEP SW FLOW GUIDES THE TROPICAL AIR INTO THE EASTERN CAROLINAS. SURFACE PRESSURE FIELDS REMAIN WEAK IN THIS TIME FRAME AND MESOSCALE SURFACE FEATURES WILL DICTATE CONVECTIVE TRENDS...SUCH AS THE LAND BREEZE...SEA BREEZE FRONT AND OUTFLOW BOUNDARIES. A POTENTIAL FOR LOCALIZED FLOODING EXISTS SINCE STORM MOTION WILL BE QUITE LAZY IN PULSE TYPE THUNDERSTORMS WHOSE DOWNBURSTS WILL VERY LIKELY PERPETUATE ADDITIONAL STORMS. TEMPERATURES WILL ADHERE CLOSE TO CLIMATOLOGY FOR EARLY AUGUST BUT MINIMUM TEMPERATURES MAY RUN A FEW DEGREES ABOVE NORMAL DUE TO CLOUDS AND THE VERY TROPICAL AIR MASS ACROSS THE REGION. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...PERIOD WILL BE MARKED BY SUBTLE 5H TROUGHING IN VARYING STRENGTHS. TROUGH AXIS REMAINS WEST OF THE AREA...KEEPING DEEP MOIST SOUTHWEST FLOW IN PLACE THROUGH SATURDAY. WEAK FRONT STALLED NORTHWEST OF THE AREA TUE WILL DRIFT INTO THE AREA WED AS IT WEAKENS...BECOMING LITTLE MORE THAN A SURFACE TROUGH. SEVERAL FACTORS SUGGEST A CONVECTIVELY ACTIVE LONGER TERM PERIOD. LOW LEVEL CONVERGENCE ALONG THE SEA BREEZE...SURFACE TROUGH...AND OUTFLOW BOUNDARIES WILL BE ENHANCED BY DIVERGENCE ALOFT...AS WILL DIURNAL INSTABILITY. NOR WILL THERE BE A LACK OF DEEP MOISTURE...WITH FORECAST SOUNDINGS SHOWING PRECIPITABLE WATER VALUES ABOVE 2 INCHES FOR MUCH OF THE PERIOD. HARD TO PICK WHICH DAYS ARE MORE FAVORABLE POP WISE THOUGH WED AND FRI STAND OUT. WED WEAK SHORTWAVE MOVES NORTHEAST FROM THE GULF COAST AND FRI THE 5H TROUGH BECOMES A LITTLE MORE DEFINED...INCREASING DIVERGENCE. TEMPERATURES WILL REMAIN NEAR CLIMO THROUGH THE PERIOD. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 06Z...VFR EXPECTED THROUGH MUCH OF THE VALID PERIOD. TWO EXCEPTIONS...POTENTIAL PATCHY/LIGHT FOG AND LOW CEILINGS FOR THE EARLY MORNING HOURS MAINLY ACROSS INLAND TERMINALS...AND THE THREAT FOR CONVECTION LATE THIS MORNING FOR COASTAL TERMINALS...AND THIS AFTERNOON FOR INLAND TERMINALS. TROPICAL ATMOSPHERE HAS TAKEN OVER THE FA. WILL OCCASIONALLY OBSERVE ONSHORE MOVEMENT OF MODERATE/TOWERING CU EARLY THIS MORNING. HAVE INDICATED VCSH FOR THE 2 MYRTLES FROM THIS ONSHORE MOVEMENT. FOR THE INLAND TERMINALS...COULD SEE A BRIEF PERIOD OF LOW CEILINGS AND BR LEADING UP TO SUNRISE. AFTER DAYBREAK...ANY LINGERING FOG AND LOW CEILINGS WILL QUICKLY DISSIPATE ALLOWING FOR VFR TO PREVAIL. WITH A VERY TROPICAL AIRMASS IN PLACE AND DEEP SE-S FLOW THRU THE ATM COLUMN...ANTICIPATE MODERATE AND TOWERING CU TO DEVELOP AND/OR MOVE ONSHORE THROUGHOUT THE DAY. LOOK FOR AN INCREASED POTENTIAL FOR MID TO LATE MORNING CONVECTION AT THE COAST...MIGRATING TO INLAND TERMINALS THIS AFTERNOON...WITH THE AID OF THE RESULTANT WIND BOUNDARY/SEABREEZE. SE TO S WINDS WILL PREVAIL WITH 5 TO 10 KT INLAND TERMINALS...5 TO 15 KT FOR THE COASTAL TERMS. FOR THE EVENING HOURS...ANY LINGERING CONVECTION/SHRA SHOULD QUICKLY DISSIPATE AROUND SUNSET. FOR THE MYR TAF...WILL NOT INCLUDE VIS AMEND IN THE LAST LINE. REASON...NO OVERNIGHT VSBY BEING REPORTED IN THE MYR METAR...WHICH HAS BEEN OCCURRING FOR SEVERAL DAYS NOW. EXTENDED OUTLOOK...DAILY CHANCE OF MORNING MVFR/IFR VSBYS AND LOW CEILINGS FROM BR/FG...AND DAILY THREAT FOR DIURNALLY DRIVEN CONVECTION EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...WIND AND SEA OBSERVATIONS ARE SUPPORTED BY THE CURRENT FORECAST AND NO UPDATES ARE NEEDED. RADAR SHOWS SHOWER ACTIVITY BECOMING MORE ISOLATED IN NATURE CURRENTLY...AND THE LATEST COUPLE OF HRRR MODEL RUNS SHOW VERY FEW SHOWERS REMAINING AFTER MIDNIGHT. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... SOUTH-SOUTHEAST WINDS 10-15 KT WILL CONTINUE OVERNIGHT AS WEAK LOW PRESSURE PUSHES ONTO THE FLORIDA EAST COAST. THIS SAME FLOW HAS ENOUGH VERTICAL EXTENT TO PUSH SCATTERED SHOWERS NORTH-NORTHWESTWARD ACROSS THE COASTAL WATERS. LATEST HIGH-RESOLUTION MODELS SHOW THE BEST COVERAGE FOR THESE SCATTERED SHOWERS SHOULD BE THIS EVENING WITH A LITTLE LESS COVERAGE AFTER MIDNIGHT. SEAS SHOULD AVERAGE 2-3 FT WITH SPECTRAL WAVE PLOTS SHOWING PEAKS IN POWER AT AROUND 6 AND 8 SECOND PERIODS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...SINCE ERNESTO WILL TRACK ACROSS THE SOUTHERN CARIBBEAN...ISLANDS WILL BLOCK ANY CHANCE OF LONG PERIOD WAVES REACHING THE NC COAST SUNDAY AND MONDAY. SE WINDS AROUND 15 KT SUNDAY WILL BUILD SEAS TO 3-4 FEET PRIMARILY IN SE WAVES WITH WAVE INTERVALS AROUND 6-7 SECONDS SUNDAY. WINDS WILL TURN SOUTHERLY AND EASE A BIT MONDAY AS A WEAK TROPICAL WAVE MOVING ACROSS FLORIDA BREAKS INTO THE GULF OF MEXICO. SEAS MAY SUBSIDE A FOOT OR SO MONDAY...BUT RESIDUAL WAVE ENERGY FROM THE SSE FETCH COULD KEEP SEA HEIGHTS STEADY AND A 2-4 FOOT RANGE...HIGHEST OFFSHORE UN-CONSUMED BY BOTTOM FRICTION AND SHOALING. ALL MARINERS ARE ENCOURAGED TO GET A FIX ON RADAR TRENDS BEFORE HEADING OUT TO ASCERTAIN THE THREAT OF OCEAN STORMS...SINCE THE TROPICAL AIR MASS WILL SUPPORT ISOLATED TO SCATTERED STORMS JUST ABOUT ANY TIME OF DAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 PM SATURDAY...BERMUDA HIGH AND STALLED FRONT/PIEDMONT TROUGH WILL MAINTAIN THE TYPICAL SUMMERTIME CONDITIONS ACROSS THE WATERS. SOUTHWEST FLOW WILL GENERALLY RANGE BETWEEN 10 AND 15 KT AND SEAS RUNNING 2 TO 3 FT WITH ISOLATED 4 FT WELL AWAY FROM SHORE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...MJC LONG TERM...III AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
137 AM EDT SUN AUG 5 2012 .SYNOPSIS... MUGGY AUGUST AIR THROUGH WEEKEND. WITH A LOCAL DOWNPOUR POSSIBLE. MORE WIDESPREAD AND ORGANIZED CONVECTION LIKELY SUNDAY...WELL AHEAD OF COLD FRONT. DRIER AIR TRIES TO CREEP SOUTH MONDAY. && .NEAR TERM /THROUGH TODAY/... 130 AM UPDATE...NO SIGNIFICANT CHANGES MADE TO ONGOING FORECAST. PREVIOUS DISCUSSION... CONVECTION CURRENTLY DEVELOPING IN ASSOCIATION WITH WEAK VORT MAX SHOWING UP ON RAP MOVING INTO CWA FROM THE WEST. DOWNPOURS WILL BE POSSIBLE WITH THESE STORMS...AND ISOLATED FLASH FLOODING MAY OCCUR. NOT EXPECTING FLASH FLOOD THREAT TO BE WIDESPREAD ENOUGH TO WARRANT A SHORT FLASH FLOOD WATCH THOUGH THIS EVENING. TOMORROW IS ANOTHER STORY...MOISTURE CONTINUES TO INCREASE OVERNIGHT...WITH PWAT VALUES CLIMBING TO OVER 2.25 INCHES BY 18Z SUNDAY ON THE NAM AND GFS. EXPECT WIDESPREAD PRECIPITATION...WITH VERY HEAVY RAINFALL SUNDAY AFTERNOON INTO SUNDAY NIGHT...AND OPTED TO ISSUE A FLASH FLOOD WATCH FOR LINE ROUGHLY HTS TO CKB AND SOUTH. ONE THING TO WATCH WILL BE STORM SPEEDS...WITH 20-30KTS MID LEVEL FLOW...STORMS WILL BE PROGRESSIVE...BUT WITH FLASH FLOOD GUIDANCE BETWEEN 1.5 AND 2 INCHES ACROSS A LOT OF THE WATCH AREA...EVEN STORMS THAT ARE MOVING COULD EASILY REACH THIS THRESHOLD. PLUS...IF ANY TRAINING CELLS OCCUR THREAT WILL INCREASE GREATLY. AS FOR SEVERE THREAT...MODELS HAVE BEEN BACKING OFF ON INSTABILITY A BIT. THINK THIS IS A GOOD TREND...DUE TO MORE CLOUDS LEADING TO LESS HEATING. STILL...1500-2000 J/KG CAPE SHOULD BE ENOUGH TO TAP INTO GOOD MID-LEVEL FLOW AND PRODUCE STRONG TO SEVERE WIND GUSTS IN THE TALLER STORMS. BLENDED IN MET GUIDANCE FOR TEMPS OVERNIGHT...AS IT HAS BEEN PERFORMING QUITE WELL LATELY...WHICH RESULTED IN MINIMAL CHANGES. WITH MORE CLOUDS AROUND...BLENDED IN THE MAV FOR HIGHS TOMORROW LIKING ITS DEPICTION OF COOLER TEMPS IN SE OHIO WHERE PRECIP WILL REACH FIRST. THIS RESULTED OVERALL IN A BIT COOLER DAY THAN PREVIOUS FORECAST. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... WE ARE HOPING THE PREFRONTAL CONVECTION DOES NOT ORIENT MORE EAST TO WEST...BUT THE FLASH FLOOD WATCH WAS POSTED EARLY...FOR THAT POSSIBILITY. AS WE HEAD INTO SUNDAY EVENING...OUR SOUTHERN COUNTIES SEEM TO BE MORE VULNERABLE TO SOME TRAINING...DESPITE THE 25 TO 30 KNOT CELL MOVEMENT THAT WE ARE EXPECTED. WILL BASE FORECAST ON SURFACE FRONT FROM NEAR EKN TO CRW TO SOUTH OF HTS AT 12Z MONDAY. SO HAD TO LEAVE SOME CHANCE POPS ALONG THAT FEATURE. PICTURING LOW CLOUDS ALONG THAT FRONT TOO. PROBABLY MOSTLY JUST LINGERING RAIN SHOWERS RATHER THAN THUNDER. PROBLEM THEN BECOMES...HOW LONG TO LINGER SOME 20/30 POPS IN OUR EXTREME SOUTH INTO TUESDAY. WE ARE TYPICALLY LEARY OF THE DRIER AIR IN THE LOW LEVELS MAKING IT THROUGH THE SOUTHERN MOUNTAINS. SO EVEN THOUGH THE MID LEVELS SHOULD DRY OUT...WILL NOW HOLD ONTO SOME 20/30 POPS IN SW VIRGINIA TO NEAR BECKLEY FOR TUESDAY. THERE COULD BE WIDESPREAD FOG MONDAY NIGHT FROM EKN TO CRW INTO THE COAL FIELDS. YET...BEING THE THIRD NIGHT INTO THE FUTURE...WILL HOLD OFF INCLUDING THOSE SPECIFICS FOR NOW. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... 12Z GFS AND 12Z ECMWF SOLUTIONS CONTINUE TO AGREE THAT THE MID LEVEL RIDGE...BAKING THE PLAINS THIS SUMMER...WILL SLIDE BACK WEST INTO THE GREAT BASIN...WITH A STRONG TROF SWINGING THROUGH OUR VICINITY ON DAY 7...WITH THE SURFACE FRONT LIKELY AHEAD OF IT...ON DAY 6/FRIDAY. PROBLEM FOR WEDNESDAY AND THURSDAY IS THE DEEP MOISTURE LINGERING TO OUR SOUTHEAST. WILL TRY TO HOLD WEDNESDAY DRY MAINLY FOR COUNTIES NORTH OF A HTS-CRW-EKN LINE...WITH SOME 20/30 POPS ALONG OUR SOUTHEASTERN COUNTIES WEDNESDAY. WENT ALONG WITH HPC MEDIUM RANGE CHANCE POPS FOR THURSDAY AND FRIDAY...WITH A COOL DOWN FOR SATURDAY. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... 06Z SUNDAY THRU 06Z MONDAY...GENERALLY VFR CEILINGS 5000-8000 FEET DEVELOPING OVERNIGHT MINIMAL FOG IF ANY DUE TO SOUTHERLY BREEZES BEING MAINTAINED. AFTER 12Z...COLD FRONT APPROACHES FROM THE WEST WITH INCREASING SHOWERS AND THUNDERSTORMS FROM WEST TO EAST ON SUNDAY. SOME STORMS MAY BE SEVERE. INTERMITTENT MVFR/IFR CONDITIONS WILL LIKELY RESULT IN STRONGER STORMS. OUTSIDE OF STORMS GENERALLY VFR CEILINGS 3500-4500 FEET BEFORE LOWERING AROUND 21Z. EXPECT GUSTY SOUTHWEST WINDS AHEAD OF THE FRONT ON SUNDAY. IFR CIGS WILL BE POSSIBLE MAINLY AT NORTHERN STIES AFTER 00Z MONDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND INTENSITY OF SHOWERS AND THUNDERSTORMS SUNDAY MAY VARY...AND WILL DEPEND OF AMOUNT OF CLOUDS AND HEATING. FLIGHT CONDITIONS MAY VARY MAINLY AFTER 18Z. 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 SUN 08/05/12 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 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 M M H H H M 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 06Z MONDAY... IFR POSSIBLE IN LOW STRATUS NEAR SURFACE FRONT MONDAY MORNING...MAINLY AT SOUTHERN AND EASTERN SITES. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR WVZ005-006-013>020-024>040-046-047. OH...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR OHZ087. KY...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ/50 SHORT TERM...KTB/ARJ LONG TERM...KTB AVIATION...50
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
158 AM EDT SUN AUG 5 2012 .SYNOPSIS... AN APPROACHING COLD FRONT WILL BRING AN INCREASE IN HUMIDITY AND SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS THIS EVENING...AND AGAIN ON SUNDAY. SOME OF WHICH MAY BE STRONG TO SEVERE ON SUNDAY...BEFORE DRIER AIR BUILDS IN FOR EARLY NEXT WEEK. OVERALL THE PATTERN FOR EASTERN NORTH AMERICA IS IN TRANSITION WITH THE EXPECTED DEVELOPMENT OF A BROAD TROUGH OVER THE NEXT 4 TO 8 DAYS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SCT-BKN ALTO CU CLOUDS /THE REMNANTS OF EARLIER CONVECTION/ WILL CONTINUE TO DRIFT EAST ACROSS THE FCST AREA OVER THE NEXT SEVERAL HOURS. A SHIELD OF THICKENING CIRRUS BLOWING OFF THE WRN OHIO MCS WILL SPREAD INTO THE WRN MTNS BY 05Z. THE EASTERN EDGE OF A NORTH/SOUTH BAND OF ANOMALOUSLY HIGH PWATS OF NEARLY 2 INCHES WILL EDGE INTO THE FAR NW ZONES TWD DAYBREAK SUNDAY...ACCOMPANIED BY INCREASING LLVL SOUTH SOUTHWESTERLY SHEAR. 850 MB WINDS WILL INCREASE TO AROUND 35 KTS OVERNIGHT...WHICH RANKS ABOUT 3 STANDARD DEVIATIONS FROM NORMAL. THIS INCREASING LOW LEVEL FORCING AND HIGH AMOUNT OF MOISTURE WILL SUPPORT ANOTHER FEW CLUSTERS OF LATE NIGHT SHOWERS AND SCATTERED TSRA MOVING ACROSS PORTIONS OF THE CWA WELL AFTER MIDNIGHT. A LINE OF STRONG TO SVR TSRA WAS RACING EAST TWD NCENT OHIO AT AROUND 45 KTS LATE THIS EVENING. THIS LINE OF INTENSE CONVECTION SHOULD WEAKEN A BIT LATE TONIGHT AS IT MOVES INTO THE SLIGHTLY LESS UNSTABLE AIRMASS ACROSS CENTRAL AND WRN PENN. LINEAR EXTRAPOLATION OF THE OHIO SQUALL LINE PLACES IT ACROSS THE MTNS OF WRN PENN BY AROUND 07Z...AND NEAR THE SUSQ MAINSTEM AROUND 09Z SUNDAY. AGAIN...PRIOR TO THIS WEAKENING LINE OF TSRA...ANOMALOUSLY STRONG 850 MB MOISTURE FLUX SHOWN BY THE SREF WILL SUPPORT ADDITIONAL...DISCRETE TSRA MOVING NE IN ITS ADVANCE. SHORT RANGE MODELS SUCH AS THE HRRR AND 4 KM NAM CONCUR ON THE REGENERATION OF CONVECTION IN THE FORM OF SCATTERED TSRA WELL AFTER MIDNIGHT...BUT DON/T SEEM TO BE LOCKING ONTO THE THE CURRENT OHIO MCS AT ALL. HRRR FIRES UP TSRA ACROSS THE LAURELS AND CENTRAL MTNS...WHILE IN CONTRAST THE 4 KM NAM SHOWS A FAIRLY LARGE AREA OF SHOWERS/TSRA MOVING NE NEAR AND JUST TO THE SE OF INTERSTATE 81 AFTER 05Z. LOWS WILL RANGE FROM THE MID TO UPPER 60S ACROSS THE MTN LOCATIONS...TO THE LOWER 70S IN THE SOUTHERN VALLEYS AND LOWER SUSQ REGION. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... FRONTAL SYSTEM TO OUR WEST AND THE RIDGE OVER THE ATLANTIC WILL SEND A DEEP PLUME OF MOISTURE WITH 2-3 SIGMA ABOVE NORMAL PW EAST ACRS THE REGION. WHILE THE STRONGEST SWRLY LLVL FLOW WILL LIKELY LIFT NE OF OUR AREA...THE FLOW WILL BE RATHER STRONG FOR EARLY AUG. CAPE VALUES ARE GOOD FOR SEVERE WEATHER BUT NOT OVERLY IMPRESSIVE. BUT OVER 20KTS OF 1KM SHEAR WITH 1200 TO 1800JKG-1 IMPLIES DEEP UPDRAFTS AND GOOD SHEAR. THIS SHOULD FAVOR THE DEVELOPMENT...MAINLY FROM MID AFTERNOON INTO EVENING OF STRONG TO POTENTIAL SEVERE THUNDERSTORMS...FAVORING MORE LINEAR SYSTEMS WITH POTENTIAL BOW DEVELOPMENT. MOST GUIDANCE SHOWS STRONG LOW-LEVEL SHEAR WHICH WILL REQUIRE MONITORING. MULTI-CELLULAR DAY LIKELY WITH BOWING SEGMENTS HIGH PROBABILITY THINKING AT THIS TIME. MOISTURE FLUX...OFTEN ALIGNS WELL WITH OUR BETTER SEVERE EVENTS PEAKS 1800 UTC SUNDAY TO ABOUT 0000 UTC MONDAY. GOOD BET STRONG STORMS FROM ABOUT 2 PM SUNDAY UNTIL 10 PM IN EAST. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... BY MONDAY MORNING...COLD FRONT WILL BE JUST SE OF CWA. WILL TAKE SOME TIME TO CLEAR OUT RESIDUAL MOISTURE IN SOUTHEAST. BUT WITH WESTERLY WINDS...DRIER AIR WILL EVENTUALLY WORK INTO THE BOUNDARY LAYER IN THE SE. PW FALLS BELOW NORMAL STATE WIDE MONDAY. CENTER OF SFC HIGH SETTLES OVER PA MON NIGHT/TUE KEEPING FORECAST DRY. WEAK WAVE OVER SE U.S. SLIDES UP THE COAST FOR WED/THU...NUDGING MOISTURE BACK INTO CWA. SO INTRODUCED SLIGHT CHANCE FOR A TSTM WED/THU AS HUMIDITY BEGINS TO INCREASE. MORE POTENT TROUGH APPROACHES IN NW FLOW FOR THU NIGHT-FRI NIGHT. MODELS HANDLING THIS FEATURE WELL...THOUGH GFS TRIES TO LIFT TROUGH NORTHWARD. EITHER WAY...CHANCE OF SHOWERS/TSTMS FITS THE BILL BEFORE A MAINLY DRY WEEKEND. TEMPERATURES WILL BE NEAR NORMAL TO START THE WEEK...THEN SLOWLY RISE BACK ABOVE NORMAL FOR MIDWEEK. AS HUMIDITY INCREASES LATE WEEK AHEAD OF APPROACHING TROUGH...TEMPS AGAIN GET A BIT MUGGY - EVEN THOUGH THEY REMAIN JUST A FEW DEGREES ABOVE NORMAL. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... OTHER THAN SEG...NO FOG AT THIS TIME. WINDS TRYING TO PICK UP A LITTLE...THUS CUT BACK ON FOG. CONVECTION ACROSS THE NW MOUNTAINS IS FALLING APART. ACTIVITY ACROSS OH SHOULD TURN SLIGHTLY MORE TO THE RIGHT... BUT IS ALSO WEAKENING. THUS MAINLY VFR CONDITIONS EXPECTED OVERNIGHT...EXCEPT FOR A LITTLE FOG IN FEW LOCATIONS. STILL EXPECT STRONG TO SEVERE STORMS BY LATE AFTERNOON... INTO THIS EVENING...GIVEN TIMING OF FRONT AND DYNAMICS. IMPROVING CONDITONS FROM LATER MONDAY INTO MID WEEK... AS HIGH PRESSURE BUILDS INTO THE AREA. OUTLOOK... .MON...CHC OF A SHOWER OR STORM EARLY...THEN MAINLY VFR. .TUE-THU...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT/RXR LONG TERM...RXR AVIATION...MARTIN
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1229 AM CDT SUN AUG 5 2012 .PREV DISCUSSION... /ISSUED 922 PM CDT SAT AUG 4 2012/ DISCUSSION...WATER VAPOR SATELLITE/UPPER AIR PROFILER/WSR-88D VAD WIND PROFILES INDICATE A SHORTWAVE ACROSS SOUTHWEST MISSOURI THIS EVENING. THIS IS RESULTING IN NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS SOUTHWEST AND SOUTH CENTRAL MISSOURI. TEMPERATURES AS OF 8 PM CDT ARE IN THE 80S AT MOST LOCATIONS. SHOWER AND THUNDERSTORM CHANCES ALONG WITH THE POTENTIAL FOR STRONG TO PERHAPS SEVERE THUNDERSTORMS OVERNIGHT ARE THE PREDOMINANT CONCERNS IN THIS EVENING/S UPDATE. LATEST SHORT TERM RUC MODEL ALONG WITH CONVECTIVE TRENDS SUGGEST A POTENTIAL FOR THIS ACTIVITY TO BEGIN PROPAGATING EAST SOUTHEAST INTO AT LEAST THE NORTHWEST ONE THIRD OF THE MID SOUTH THIS EVENING. HAVE DISCOUNTED THE 00Z WRF THIS EVENING THUS FAR AS IT HAS EXPERIENCED SOME DIFFICULTY HANDLING THE CURRENT CONVECTIVE ACTIVITY OVER SOUTHERN MISSOURI. RADAR TRENDS INDICATE SOME WEAKENING HAS BEGUN TO OCCUR WITH THIS COMPLEX. AN ISOLATED STRONG TO PERHAPS SEVERE THUNDERSTORM MAY BE POSSIBLE ACROSS PORTIONS OF NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL IF IT BEGINS TO DROP INTO THE FORECAST AREA IN THE NEXT HOUR OR TWO. WILL UPDATE GRIDS TO ADJUST TIMING OF SHOWER/THUNDERSTORM CHANCES BASED ON LATEST TRENDS AND ADJUST ALL OTHER ELEMENTS AS NEEDED. UPDATED GRIDS WILL BE AVAILABLE SHORTLY. CJC && .PREV DISCUSSION... /ISSUED 333 PM CDT SAT AUG 4 2012/ DISCUSSION... FINALLY WILL SEE A PATTERN SHIFT OVER THE NEXT WEEK AS AN UPPER TROF MOVES OVER THE EASTERN UNITED STATES. EXPECT TWO COLD FRONTS TO MOVE THROUGH THE REGION WHICH SHOULD FINALLY BRING AN END TO THE HEAT WAVE. TONIGHT...A COLD FRONT THAT CURRENTLY STRETCHES FROM CHICAGO ILLINOIS TO ST JOSEPH MISSOURI WILL SINK SOUTH. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG THE FRONT THIS EVENING. SOME STORMS MAY BECOME SEVERE ALONG THE LINE. EXPECT THE LINE TO BEGIN MOVING INTO THE MIDSOUTH SHORTLY AFTER MIDNIGHT. THE LINE WILL LIKELY BE DYING BY THIS POINT BUT STILL CAN/T RULE OUT A FEW STRONG TO SEVERE STORMS. OTHERWISE...THIS EVENING SHOULD BE RELATIVELY QUIET WITH THE EXCEPTION OF A FEW STORMS ACROSS PORTIONS OF NORTHEAST MISSISSIPPI THAT ARE DEVELOPING IN RESPONSE TO A SHORTWAVE MOVING THROUGH THE REGION. HOWEVER THESE STORMS SHOULD BE SHORT-LIVED AS THE SHORTWAVE IS PUSHING EAST OF THE AREA. LOWS WILL BE IN THE MID TO UPPER 70S. SUNDAY...COLD FRONT MOVES INTO THE MIDSOUTH. EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP IN RESPONSE TO THE FRONT INTERACTING WITH DAYTIME HEATING. EXPECT SOME STORMS TO BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. THE BIG QUESTION IS HOW MUCH ACTIVITY FROM THE OVERNIGHT THUNDERSTORMS WILL STILL BE AROUND AT 7 AM. THIS WILL PLAY A HUGE ROLE ON LATER THUNDERSTORM DEVELOPMENT AS WELL AS TEMPERATURES. CLOUD COVER FROM SOME SHOWERS THIS MORNING...REALLY PREVENTED DEVELOPMENT ACROSS WEST TENNESSEE. CLOUDS ALSO KEPT TEMPERATURES DOWN ACROSS WESTERN KENTUCKY. DEWPOINTS HAVE BEEN IN THE MID TO UPPER 70S AND EXPECT SIMILAR CONDITIONS TOMORROW. WILL FORECAST HIGHS IN THE LOWER TO MID 90S. THESE TEMPERATURES COMBINED WITH THE DEWPOINTS WILL PRODUCE HEAT INDICES ABOVE 105 DEGREES. BUT WITH SO MUCH UNCERTAINTY WILL HOLD OFF ON ISSUING A HEAT ADVISORY. WILL LET MIDNIGHT SHIFT SEE HOW OVERNIGHT CONVECTION EVOLVES TO MAKE FINAL CALL. SUNDAY NIGHT INTO MONDAY...FRONT WILL CONTINUE TO SINK SOUTH ACROSS THE CWA. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ACROSS NORTH MISSISSIPPI. MODELS ARE NOT AS QUICK TO PUSH DRIER AIR INTO THE CWA BEHIND THE FRONT. EXPECT LOWS TO STILL BE IN THE LOWER TO MID 70S WITH HIGHS ON MONDAY REMAINING IN THE LOWER TO MID 90S. MONDAY NIGHT THROUGH THURSDAY...SOME DRIER AIR DOES MOVE INTO THE MIDSOUTH. ALL MODELS INDICATING DIURNAL CONVECTION DEVELOPING EACH AFTERNOON MAINLY ACROSS SOUTHEASTERN PART OF THE CWA WHERE THE DEWPOINTS REMAIN HIGHER. LOWS WILL RANGE FROM THE UPPER 60S TO MID 70S WITH HIGHS IN THE LOWER TO MID 90S. THURSDAY NIGHT THROUGH FRIDAY NIGHT...A SECOND COLD FRONT WILL SINK SOUTH AS A BROAD UPPER TROF MOVES OVER THE EASTERN UNITED STATES. EXPECT CHANCES FOR SHOWERS AND THUNDERSTORMS TO EXPAND OVER THE ENTIRE CWA. HIGH TEMPERATURES ON FRIDAY MAY BE A TAD COOLER DUE TO CLOUD COVER AND THUNDERSTORMS. SATURDAY...SFC HIGH PRESSURE WILL MOVE INTO THE REGION. COOLER AND DRIER AIR WILL FILTER INTO THE REGION. EXPECT PLEASANT CONDITIONS AS A RESULT WITH HIGHS IN THE UPPER 80S FOR THE MOST PART. KRM && .AVIATION... 06Z TAF SET LINE OF DEVELOPING TSRA MAY IMPACT JBR WITHIN THE NEXT HOUR OR SO. NOT CONFIDENT THAT TS WILL CONTINUE TO DEVELOP AND IMPACT MEM OR MKL LATER IN THE NIGHT...BUT A FEW SHOWERS ARE DEVELOPING. WINDS WILL REMAIN SSW OVERNIGHT BETWEEN 5 AND 10 KNOTS. A COLD FRONT WILL APPROACH TOMORROW STALLING ACROSS NORTH MISSISSIPPI INTO SOUTHEAST ARKANSAS. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE THROUGHOUT THE DAY SUNDAY...CONTINUING INTO SUNDAY NIGHT. INCLUDED VCTS AT ALL SITES SUNDAY...WILL ADD PREVAILING TS WHEN STORMS DEVELOP AND THERE IS SOMETHING TO TIME BETTER. IFR VIS AND WIND WILL BE POSSIBLE AT LOCATIONS IMPACTED BY THUNDERSTORMS. WINDS WILL SHIFT FROM THE NORTH DURING THE LATE AFTERNOON HOURS AT JBR...MKL AND MEM. && .PRELIMINARY POINT TEMPS/POPS... MEM 94 75 92 73 / 60 60 20 10 MKL 90 71 90 67 / 60 60 20 10 JBR 92 70 93 69 / 60 30 10 10 TUP 93 75 91 72 / 60 60 50 20 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1102 PM CDT SAT AUG 4 2012 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TODAY THROUGH SUNDAY. STORMS FIRED ALONG BOUNDARY IN MANITOWOC AND WAUPACA COUNTIES THIS AFTN...AS THE MORNING RUNS OF THE HRRR MODEL INDICATED. CORRIDOR OF HIGH INSTABILITY FROM S WI INTO THE FAR E PART OF THE STATE AND CONVERGENCE ALONG BOUNDARIES ENOUGH TO INITIATE DEEP CONVECTION. MAIN LINE OF SHOWERS AND STORMS...HOWEVER...MOVING INTO THE WEST PART OF FORECAST AREA. THIS WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND EARLY EVENING PER LATEST RUN OF HRRR. BEST CHANCE OF SEVERE WILL BE SOUTH OF FORECAST AREA...BUT STILL A THREAT IN THE EAST-CENTRAL IN UNSTABLE AIRMASS AND INTERACTION OF LOW-LEVEL BOUNDARIES. UPPER TROF WILL QUICKLY SWING THROUGH TONIGHT. SMALL CHANCE FOR LINGERING SHOWERS BEHIND MAIN LINE LATER THIS EVENING. OTHERWISE...CLEARING SKIES ACROSS MUCH OF AREA. EXCEPTION IS IN THE FAR NORTH CLOSER TO THE UPPER LOW AND RESIDUAL MOISTURE. TEMPS TONIGHT AND SUNDAY ARE A BLEND OF MODELS...CLOSE TO PREVIOUS FORECAST. .LONG TERM...SUNDAY NIGHT THROUGH NEXT FRIDAY. MEAN LONGWAVE PATTERN FOR THE EXTENDED FORECAST PERIOD GENERALLY CHARACTERIZED BY A TROUGH OVER THE OHIO VALLEY AND RIDGE OVER THE INTERMOUNTAIN WEST. WESTERN GREAT LAKES REGION WILL RESIDE IN NORTHWESTERLY FLOW REGIME WITH AN OCCASIONAL EMBEDDED SHORTWAVE DISTURBANCES TRAVERSING THE AREA. TIMING AND INTENSITY OF EMBEDDED SHORTWAVE DISTURBANCES WITHIN THIS FLOW REGIME ARE TYPICALLY PROBLEMATIC...THUS FORECAST CONFIDENCE IN THIS REGARD IS LOW TO MEDIUM. EARLY IN THE WORK WEEK... DAYTIME TEMPERATURES WILL START OUT ABOVE NORMAL...THEN SLOWLY FALL BACK TO NEAR...OR PERHAPS SLIGHTLY BELOW NORMAL FOR EARLY AUGUST. SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD EASTWARD ACROSS THE FORECAST AREA SUNDAY NIGHT INTO MONDAY. WENT ON THE COOLER SIDE SIDE OF AVAILABLE GUIDANCE WITH RESPECT TO MIN TEMPERATURES SUNDAY NIGHT GIVEN CLEAR SKIES...LIGHT WINDS AND RATHER DRY DRY AIRMASS. MONDAY LOOKS LIKE A PLEASANT DAY WITH SUNNY SKIES...RELATIVELY LIGHT WINDS WITH DAYTIME HIGHS A FEW DEGREES ABOVE NORMAL. SHORTWAVE DISTURBANCE THEN FORECAST TO HEAD SOUTHEAST ACROSS SOUTHERN HUDSON BAY MONDAY NIGHT INTO EARLY TUESDAY. ASSOCIATED COLD FRONT WILL GET SHOVED SOUTHEAST TOWARD NORTHWEST WISCONSIN BY AROUND 06Z TUESDAY. APPEARS TO BE A PLUME OF HIGHER MID-LEVEL LAPSE RATES AND MODEST 850 WAA OUT AHEAD OF THIS SYSTEM. HOWEVER AVAILABLE MOISTURE IS SOMEWHAT LIMITED. THUS...HAVE MAINLY SMALL CHANCE POPS OVER NORTHWEST COUNTIES OVERNIGHT...THEN CARRY THESE SMALL POPS SOUTHEAST ACROSS THE AREA TUESDAY MORNING. MAJORITY OF GUIDANCE SUGGEST THAT FRONT WILL PASS SOUTHEAST OF THE FORECAST AREA BY ABOUT 18Z TUESDAY WITH CAA TO ENSUE DURING THE AFTERNOON. WEAK HIGH PRESSURE RETURNS TO THE AREA TUESDAY NIGHT INTO EARLY WEDNESDAY...WITH NEXT DISTURBANCE ALREADY APPROACHING THE NORTHERN MISSISSIPPI VALLEY BY WEDNESDAY MORNING. MODEL CONSENSUS SUGGESTS THIS SYSTEM WILL BE A BIT MORE POTENT AS IT TRAVERSES SOUTHEAST ACROSS THE FORECAST AREA THURSDAY. OPERATIONAL GFS AND ECMWF ARE A BIT FURTHER SOUTH WITH STRENGTHENING SURFACE LOW WHILE GEM A BIT FURTHER NORTH. BOTTOM LINE IS THAT IT LOOKS LIKE THERE WILL BE A PRETTY DECENT CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE DAY ON THURSDAY. BUMPED UP POPS FROM PREVIOUS FORECAST. SOME MODEL DIFFERENCES ON EVOLUTION OF UPPER TROUGH AND ASSOCIATED SURFACE LOW THURSDAY NIGHT INTO FRIDAY. SYSTEM DOES APPEARS TO SLOW DOWN SOMEWHAT AS IT DEEPENS JUST TO THE EAST OF THE FORECAST AREA...THUS PRECIPITATION COULD VERY WELL LINGER INTO FRIDAY ESPECIALLY OVER THE EASTERN HALF OF THE FORECAST AREA. CLOUDS...SCATTERED PRECIPITATION AND NORTHEASTERLY BOUNDARY LAYER FLOW ON FRIDAY WILL LIKELY HOLD TEMPERATURES MAINLY IN THE 70S. && .AVIATION...AREA OF BKN VFR STRATO-CU OVER MINNESOTA IS STILL ON TRACK TO ARRIVE OVER CENTRAL AND NORTH CENTRAL WISCONSIN OVERNIGHT. STILL NOT ENTIRELY CONFIDENT ABOUT THE BKN MVFR CIGS AT RHI LATE TONIGHT INTO THE MORNING...BUT FIGURE NOCTURNAL COOLING WILL AID THEIR DEVELOPMENT. THE BKN MVFR/VFR CIGS WILL SWING ACROSS THE REGION THROUGH ABOUT MID-MORNING TOMORROW BEFORE DRIER AIR ARRIVES FOR THE AFTERNOON AND DISSIPATES THE CLOUDS. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS ALBANY NY
637 AM EDT SUN AUG 5 2012 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND CROSS THE REGION TONIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED INTO OUR REGION IN THE WAKE OF THE COLD FRONT FOR MONDAY AND TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM EDT...PARTLY TO MOSTLY CLOUDY SKIES PREVAILED ACROSS THE FA WITH WARM AND MUGGY CONDITIONS. A FEW LIGHT SHOWERS HAVE DEVELOPED AND MOVED INTO THE WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY AND HAVE INCREASED POPS SLIGHTLY IN THOSE AREAS DURING THE NEXT FEW HOURS...OTHERWISE NO OTHER CHANGES TO PREVIOUS FORECAST. TEMPERATURES WERE GENERALLY IN THE UPPER 60S TO MID 70S ACRS THE FA. A VIGOROUS SHORT WAVE ACCOMPANIED BY A STRONG COLD FRONT WILL IMPACT OUR REGION DURING THIS PERIOD WITH THE POSSIBILITY OF A PRE-FRONTAL TROUGH CROSSING THE ALY FA LATE AFTERNOON INTO EARLY EVENING WHICH MAY ENHANCE THE CONVECTION. THERE ARE MANY INGREDIENTS IN PLACE FOR STRONG TO SEVERE THUNDERSTORMS AS WELL AS HEAVY RAIN WHICH COULD PRODUCE FLASH FLOODING ESPECIALLY WHERE CELLS TRAIN AND OR BACK BUILD. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR ALL OF EASTERN NEW YORK AND ADJACENT WESTERN NEW ENGLAND FROM 2 PM THIS AFTERNOON THROUGH EARLY MONDAY MORNING. THE TRAINING OF CELLS IS A DISTINCT POSSIBILITY AS THE COLD FRONT IS EXPECTED TO DROP FROM NORTHWEST TO SOUTHEAST AS THUNDERSTORMS MOVE FROM SOUTHWEST TO NORTHEAST ALONG AND AHEAD OF IT. PWATS RISE TO 2 TO NEARLY 2.5 INCHES THIS EVENING ALONG WITH A STRONG THETA E RIDGE H10-H8...AND K INDEX VALUES BTWN 35 AND 40. MLMUCAPES RISE UP TO 3000 J/KG THIS AFTERNOON WITH STRONG WIND FIELDS AS FA ENDS UP IN RIGHT ENTRANCE REGION OF A CYCLONICALLY CURVED 100+ KT JET ACRS ERN CANADA WHILE H8 WINDS INCREASE TO 35 TO 45 KTS AND H7 STEERING WINDS 35 TO 50 KTS FROM THE SOUTHWEST. FURTHER 0-3 KM HELICITY VALUES INCREASE TO 150 TO 250 M2/S2 LATER THIS AFTERNOON INTO THIS EVENING. THUS THE POTENTIAL FOR STRONG TO PERHAPS SEVERE WIND GUSTS EXIST WITH ANY STORMS AND SPC HAS THE ALY FA OUTLOOKED AS SLIGHT RISK IN THE DAY 1 OUTLOOK. THE THREAT OF LARGE HAIL IS CONSIDERABLY LESS AS WBZ HEIGHTS REMAIN ABOVE 12 KFT FOR MUCH OF THE PERIOD FROM THIS AFTERNOON THROUGH THIS EVENING. HAVE CHANCE POPS INCREASING TO LIKELY POPS FROM NORTHWEST TO SOUTHEAST DURING THE AFTERNOON INTO EARLY EVENING WITH LIKELY POPS ACROSS ENTIRE FA FOR MUCH OF THE EVENING WITH DECREASING POPS AFTER MIDNIGHT FROM NORTHWEST TO SOUTHEAST. EXPECT HIGHS TODAY GENERALLY IN THE LOW TO MID 80S WITH LOWS TONIGHT GENERALLY IN THE 60S TO LOWER 70S. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ANY LINGERING SHOWERS OR THUNDERSTORMS ACROSS THE SOUTHEAST PORTION OF THE FA ARE EXPECTED TO END EARLY MONDAY MORNING...OTHERWISE DRIER...MORE SEASONABLE AND MUCH LESS HUMID CONDITIONS ARE EXPECTED DURING THE SHORT TERM PERIOD WITH A GOOD DEAL OF SUNSHINE ON BOTH MONDAY AND TUESDAY AND MAINLY CLEAR SKIES MONDAY NIGHT AND TUESDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE REGION. EXPECT HIGHS ON MONDAY IN THE MID 70S TO MID 80S...LOWS MONDAY NIGHT IN THE MID 50S TO LOWER 60S...HIGHS ON TUESDAY IN THE UPPER 70S TO MID 80S AND LOWS TUESDAY NIGHT IN THE MID 50S TO MID 60S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... HAVE POPULATED THIS PORTION OF THE GRIDDED DATABASE WITH A 50/50 BLEND OF 18Z/04 HPC GUIDANCE AND 00Z/05 GMOS. WED-THU NT...A WEAKENING SHORTWAVE WILL APPROACH FROM THE WEST LATE WED...ALONG WITH AN ATTENDANT SURFACE BOUNDARY. FORCING ASSOCIATED WITH THESE FEATURES MAY TRIGGER ISOLATED SHOWERS WED AFTERNOON/EVENING ACROSS N/W AREAS...WHERE SLIGHT CHC POPS HAVE BEEN INDICATED. THIS BOUNDARY IS THEN EXPECTED TO STALL ACROSS THE REGION THU/THU NT. MARGINAL INSTABILITY...IN COMBINATION WITH WEAK FORCING FROM FRONTAL BOUNDARY MAY PRODUCE ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS ON THU...WHEN LOW CHC POPS ARE INDICATED. EXPECT TEMPS TO AVERAGE ABOVE SEASONAL LEVELS...ALONG WITH INCREASING HUMIDITY LEVELS DURING THIS TIME PERIOD...WITH DAYTIME MAXES REACHING THE MID TO UPPER 80S IN VALLEYS...AND UPPER 70S TO LOWER 80S ACROSS HIGHER ELEVATIONS. OVERNIGHT MINS SHOULD FALL INTO THE LOWER/MID 60S IN VALLEYS...AND 55-60 ACROSS HIGHER ELEVATIONS. FRI-SAT...CONFIDENCE INCREASING THAT A RATHER UNSETTLED PERIOD SHOULD OCCUR...AS AN AMPLIFYING SHORTWAVE SLOWLY APPROACHES FROM THE GREAT LAKES REGION...AND POTENTIALLY CLOSES OFF UPON APPROACHING FROM THE WEST/SOUTHWEST. AT THE SURFACE...A WAVE...OR SERIES OF WAVES ARE EXPECTED TO DEVELOP ALONG THE AFOREMENTIONED STALLED FRONTAL BOUNDARY ACROSS THE REGION. THERE REMAINS SOME UNCERTAINTY IN THE EXACT PLACEMENT AND DETAILS OF THE DEVELOPMENT OF ANY SFC WAVE...AND MOVEMENT OF FRONTAL SYSTEMS AT THIS TIME RANGE...BUT AT THE VERY LEAST...IT APPEARS THAT SEVERAL ROUNDS OF SHOWERS/THUNDERSTORMS WILL BE POSSIBLE DURING THIS TIME PERIOD. AND...DEPENDING ON HOW FAR SOUTH ANY SFC WAVE TRACKS...A PORTION OF THE REGION COULD EVEN RECEIVE A STEADY...BENEFICIAL RAINFALL. HAVE INCLUDED HIGH CHC POPS AT THIS TIME. GIVEN THE UNCERTAINTY IN FRONTAL BOUNDARIES WITH THIS SYSTEM...TEMPERATURES REMAIN TRICKY...AS A MORE SOUTHERN TRACK WITH THE LOW WOULD FAVOR NEAR OR EVEN BELOW NORMAL DAYTIME MAXES. FOR NOW...HAVE SIDED WITH THE AFOREMENTIONED 50/50 BLEND OF HPC GUIDANCE AND GMOS...WITH DAYTIME MAXES IN THE LOWER 80S IN VALLEYS...AND 70S ELSEWHERE...AND OVERNIGHT MINS MAINLY IN THE 60S AS CLOUDS AND HIGHER HUMIDITY LEVELS KEEP NIGHTTIME TEMPS RELATIVELY WARM. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... A COLD FRONT APPROACHING FROM THE WEST WILL TRIGGER NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THE FIRST HALF OF TONIGHT. VFR CONDITIONS WILL GRADUALLY BECOME MVFR...MAINLY FOR CIGS...AS LOW STRATUS ADVECTS AND/OR DEVELOPS NORTHWARD THROUGH SUNRISE. TRICKY CALL ON WHETHER IT REMAINS LOW MVFR...OR IFR. AT THIS TIME...FOLLOWED CLOSE TO THE HRRR OUTPUT...WHICH IMPLIES MAINLY MVFR CIGS INITIALLY...WITH A CHANCE FOR IFR AFTER 09Z/SUN AT ALL TAF SITES. HOWEVER...LOCAL DOWNSLOPING WITH A S/SE FLOW MAY PREVENT CIGS FROM CRASHING TO IFR AT KPSF AND KPOU. HAVE INDICATED ONLY BRIEF PERIODS OF IFR TOWARD 12Z/SUN AT THESE LOCATIONS. THIS STRATUS MAY BEGIN TO BREAK UP SUNDAY MORNING AS THE FRONTAL BOUNDARY BEGINS TO APPROACH...AND THE FLOW BECOMES MORE SW. CONDITIONS SHOULD GO BACK TO VFR AT ALL SITES BY THE LATE MORNING HOURS. SOME SHOWERS AND TSTMS ARE POSSIBLE BY LATE IN THE DAY INTO SUNDAY NIGHT AS THE FRONT CROSSES THE REGION. HAVE INDICATED A VCTS FOR ALL TAF SITES AFTER 18Z-20Z/SUN...AS THUNDERSTORMS SHOULD BECOME RATHER NUMEROUS LATER THIS AFTERNOON...WELL INTO THIS EVENING. IT IS LIKELY THAT SEVERAL DISCRETE ROUNDS OF THUNDERSTORMS OCCUR DURING THIS TIME PERIOD...WITH SOME BREAKS IN BETWEEN. THE THREAT FOR THUNDERSTORMS WILL GRADUALLY DECREASE TOWARD AND ESP AFTER 06Z/MON...FIRST AT KGFL AND KALB...AND LAST AT KPSF AND KPOU. AREAS OF MVFR/IFR FOG MAY OCCUR TOWARD AND AFTER 06Z/MON AT ALL TAF SITES. SOUTH/SOUTHEAST WINDS WILL PERSIST THROUGH DAYBREAK AT KALB AND 8-12 KT...WITH SOME GUSTS POSSIBLY REACHING 15-20 KT. ELSEWHERE...WINDS SHOULD BECOME LIGHT/VARIABLE THROUGH DAYBREAK. WINDS WILL THEN INCREASE FROM THE SOUTH BY MID MORNING AT 8-12 KT...EXCEPT STRONGER...AT 10-15 KT AT KALB...WITH SOME GUSTS OF 20-25 KT POSSIBLE. SOUTH WINDS WILL GRADUALLY VEER INTO THE SW TO W LATER THIS EVENING...AT 5-10 KT. WINDS WILL BE MUCH STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR ANY THUNDERSTORMS. OUTLOOK... SUN NIGHT...MVFR/IFR. SHRA/TSRA LIKELY EARLY. MON...VFR. SLIGHT CHC -SHRA EAST OF THE HUDSON RIVER EARLY IN THE MORNING. TUE...VFR. NO SIG WX. WED...VFR. SLIGHT CHC -SHRA/-TSRA. THU...VFR. CHC OF -SHRA/-TSRA. && .FIRE WEATHER... WET FLAG CONDITIONS ARE EXPECTED FROM THIS AFTERNOON THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND CROSS THE REGION TONIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. A MORE SEASONABLE AND DRIER AIRMASS WILL BE USHERED INTO OUR REGION IN THE WAKE OF THE COLD FRONT FOR MONDAY AND TUESDAY. && .HYDROLOGY... A FLASH FLOOD WATCH IS IN EFFECT FOR ALL OF EASTERN NEW YORK AND ADJACENT WESTERN NEW ENGLAND FROM 2 PM THIS AFTERNOON THROUGH EARLY MONDAY MORNING. A STRONG COLD FRONT WILL APPROACH OUR REGION FROM THE NORTHWEST TODAY AND CROSS THE AREA TONIGHT. SHOWERS AND THUNDERSTORMS WILL PRECEDE AND ACCOMPANY THIS BOUNDARY WITH SOME OF THE STORMS PRODUCING VERY HEAVY RAINFALL. INCREASING PRECIPITABLE WATER VALUES ARE EXPECTED THE FIRST HALF OF TONIGHT RISING TO 2 TO PERHAPS AS HIGH AS 2.5 INCHES AHEAD OF THE STRONG COLD FRONT. EXPECT THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR FROM LATER THIS AFTERNOON THROUGH LATE TONIGHT WITH TORRENTIAL DOWNPOURS OCCURRING IN SOME AREAS. IN ADDITION THUNDERSTORMS MAY TRAIN AND OR BACK BUILD ACROSS THE SAME AREA INCREASING THE POSSIBILITY OF FLASH FLOODING. RAINFALL AMOUNTS IN MANY AREAS WILL BE 1 TO 3 INCHES WITH 3 TO 6 INCHES OF RAIN POSSIBLE IN AREAS WHERE THUNDERSTORMS TRAIN AND OR BACK BUILD. WHILE RIVER FLOODING IS GENERALLY NOT EXPECTED...SIGNIFICANT WITHIN BANK RISES ARE EXPECTED ON SOME RIVERS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR CTZ001-013. NY...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR NYZ032-033-038>043-047>054-058>061-063>066- 082>084. MA...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR MAZ001-025. VT...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH MONDAY MORNING FOR VTZ013>015. && $$ SYNOPSIS...IAA/FRUGIS/11 NEAR TERM...11 SHORT TERM...11 LONG TERM...KL AVIATION...FRUGIS/KL FIRE WEATHER...11 HYDROLOGY...11
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
650 AM CDT SUN AUG 5 2012 .SHORT TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (TODAY AND TONIGHT) FOCUS INITIALLY WILL BE ON EXITING THUNDERSTORMS. LATEST RUNS OF THE RAP SEEM TO BE IN LINE WITH CURRENT EXTRAPOLATION THAT SURFACE FRONT WILL BE RIGHT ALONG THE SOUTHERN BORDER OF THE CWA AT 12Z. AXIS OF SHORTWAVE TROUGH CURRENTLY ALONG THE KS/MO BORDER WILL BE OVER SOUTHEASTERN MO WITH SOME LINGER 925-850 ALONG AND JUST NORTH OF THE SFC FRONT. HAVE ISOLATED/SCATTERED THUNDERSTORMS SLOWLY PUSHING SOUTH OF THE CWA BETWEEN 12-18Z BEFORE SUBSIDENCE SETS IN BEHIND THE SHORTWAVE. CLOUDS WILL ALSO DECREASE THROUGH MIDDAY AS LOW-MID LEVEL MOISTURE AND CONVECTIVE DEBRIS MOVES OUT OF THE AREA. STAYED WITH THE BETTER VERIFYING NAM MOS HIGHS TODAY...PARTICULARLY WHERE THERE SHOULD BE THE MOST SUN. SKIES WILL BE CLEAR TONIGHT AND WINDS SHOULD TURN LIGHT EASTERLY BY MORNING AS SURFACE HIGH CENTER PASSES THROUGH NORTHERN MO/CENTRAL IL. CAN`T RULE OUT SOME FOG DEVELOPING IN AREAS THAT HAD THE HEAVIEST RAINFALL THE PAST 24 HOURS LATE TONIGHT/EARLY MONDAY. BRITT && .LONG TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (MONDAY THROUGH SATURDAY) DRY WEATHER WILL BE THE RULE MONDAY AND TUESDAY AS LOW LEVEL MOISTURE WILL BE CUT OFF BY FRONT MOVING THROUGH TODAY AND AREA WILL BE UNDER MAINLY SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT. NAM/GFS BOTH SHOW A TROUGH MOVING ACROSS THE MIDWEST ON TUESDAY...BUT THE BEST ASCENT WILL STAY TO THE NORTH OF THE AREA AS IT BEGINS TO SHEAR OUT. STAYED CLOSER TO THE NAM MOS FOR HIGHS AS FORECAST SOUNDINGS ARE SHOWING MIXING UP TO 800MB ON MONDAY AND 700MB ON TUESDAY. LOWER 90S SEEM REASONABLE ON MONDAY WITH 850MB TEMPS NEAR 20C...AS DO MIDDLE TO POSSIBLY UPPER 90S ON TUESDAY WITH 20-24C 850MB TEMPS. DOES LOOK LIKE DEWPOINTS WILL STAY IN THE 50S DURING THE PERIOD WHICH SHOULD KEEP HEAT INDEX READINGS AT OR BELOW THE AMBIENT TEMPERATURES. THE GFS IS SHOWING A DEEPER TROUGH DIGGING IN OVER THE MISSISSIPPI VALLEY ON THURSDAY THAN IT DID PREVIOUSLY. ECMWF/CANADIAN GEM SHOW A LESS AMPLIFIED AND SLOWER SOLUTION...SO GOING SLIGHT CHANCES FOR THUNDERSTORMS SEEM THE BEST ROUTE. THEN GFS IS SHOWING ANOTHER SORTHWAVE MOVING DOWN TOWARD THE AREA BY EARLY NEXT WEEKEND WITH THE ECMWF HAVING A SLOWER SOLUTION...SO AGAIN SLIGHT CHANCES SEEM THE BEST ROUTE. 850MB TEMPS ARE SHOWING A SLOW DECLINE FROM WEDNESDAY TO SATURDAY AS 500MB HEIGHTS SLOWLY FALL WITH THE PASSAGE OF THE SHORTWAVES...SO HAVE TEMPERATURES FALLING FROM THE LOWER-MID 90S ON THURSDAY INTO MAINLY IN THE 80S ON SATURDAY. BRITT && .AVIATION... ISSUED AT 552 AM CDT SUN AUG 5 2012 COLD FRONT HAS PASSED JUST S OF COU AND STL EARLY THIS MRNG. MOST OF THE CONVECTION HAS SHIFTED S OF THE TAF SITES...ALTHOUGH COULD NOT RULE OUT AN ISOLATED SHOWER TIL 14Z SUN FROM COU TO STL. WILL LEAVE THE TAFS DRY AS THE PROBABILITY OF ANY MORE RAIN IS QUITE LOW. BAND OF LOW LEVEL CLOUDS ALONG AND JUST BEHIND THE FRONT FROM 1500-3000 FT IN HEIGHT SHOULD ADVECT SE OF THE STL METRO AREA BY 14-15Z SUN WITH LINGERING VFR LOW-MID LEVEL CLOUD COVER FROM COU TO STL AREA FOR THE REST OF THE MRNG...THEN MAINLY JUST HIGH LEVEL CLOUDS CLEARING OUT FROM NW TO SE THIS AFTN. N-NWLY SFC WIND WILL BECOME LIGHT THIS EVNG AS THE SFC RIDGE OVER THE PLAINS SHIFTS EWD TO NRN IL TGT. THERE MAY BE SOME FOG LATE TGT ESPECIALLY FOR SUS DUE TO RECENT RAINFALL ALONG WITH A CLEAR SKY AND LIGHT SFC WIND. SPECIFICS FOR KSTL...LOW LEVEL CLOUD CEILING AROUND 3000 FT SHOULD RISE IN HEIGHT LATER THIS MRNG WITH MAINLY JUST HIGH LEVEL CLOUDS THIS AFTN. NWLY SFC WIND SHOULD INCREASE TO AROUND 10 KTS LATER THIS MRNG FROM A N-NWLY DIRECTION AS A SFC RIDGE BUILDS SEWD INTO OUR AREA BEHIND THE COLD FRONT. THE SFC WIND SHOULD BECOME LIGHT THIS EVNG WITH THE SFC HIGH CENTERED JUST NE OF STL BY 12Z MON. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS NEW YORK NY
357 PM EDT SUN AUG 5 2012 .SYNOPSIS... A COLD FRONT WILL PASS THROUGH THE REGION LATE TONIGHT. HIGH PRESSURE BUILDS IN THROUGH THE MIDDLE OF THE WEEK. A SLOW MOVING FRONTAL SYSTEM MAY THEN IMPACT THE AREA FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... MAIN LINE OF TSTMS ACROSS CNTRL PA TIMED TO REACH THE WRN FRINGE OF THE CWA AROUND 1Z..TRACKING EWD AT AROUND 35KT. AHEAD OF THIS ACTIVITY...ISOLD-SCT DEVELOPMENT CAN BE EXPECTED. WINDS ALOFT ABOUT 30KT PER THE OKX VWP. THESE WINDS ARE MIXING DOWN IN ANY TSTMS...AND WILL CONTINUE TO BE THE CASE THRU THIS EVE. SOME STRENGTHENING TO UP TO 40KT ALOFT POSSIBLE AS THE GRAD INCREASES. IT APPEARS TO BE MORE STABLE OVER THE S COASTS PER STLT...SO HAVE KEPT THE FCST MAINLY DRY ACROSS PORTIONS OF LI UNTIL TNGT. ELSEWHERE...POPS ARE BASED ON THE HRRR FOR ONGOING CONVECTION WITH A BACKGROUND OF ISOLD CHANCES. MAIN THREAT WITH THE LINE APPEARS TO BE WIND AS IT APPROACHES. STILL TIME TO EVALUATE THE POTENTIAL...BUT THE DEVELOPMENT OF A SIGNIFICANT COLD POOL COULD POSE THE MOST SVR WIND THREAT. && .SHORT TERM /10 PM THIS EVENING THROUGH MONDAY NIGHT/... TSTMS WILL CONTINUE TO ROLL EWD AHEAD OF THE FRONT OVERNIGHT. THERE WILL REMAIN THE THREAT FOR AN EMBEDDED SVR STORM...ESPECIALLY ACROSS LI AS A BOUNDARY FORMS DUE TO THE ONSHORE FLOW AND LAND/SEA INTERACTION. MAIN THREAT HOWEVER WILL REMAIN THE LOC HVY RAIN. LOW TEMPS KEPT NEAR THE NAM 2M NUMBERS DUE TO THE LLVL MOISTURE IN PLACE. 12Z MODEL SUITE HAS COME IN QUICKER WITH THE CLEARING FOR MON. HAVE ACCEPTED THIS TREND BASED ON WHERE THE SYSTEM CURRENTLY IS AND THE 00Z ECMWF. FCST INDICATES A SUNNY AFTN. HUMIDITY WILL BE MUCH LOWER AS THE MOIST AIRMASS IS SHUNTED OFFSHORE. TEMPS A BLEND OF GUIDANCE AND SEASONAL. THERE IS A MDT RISK OF RIPS ON THE OCEANFRONT. MAINLY SKC AND COOL MON NGT WITH TEMPS DROPPING INTO THE 50S ACROSS THE COOL SPOTS. && .LONG TERM /TUESDAY THROUGH SUNDAY/... FAIR WEATHER THRU MIDWEEK WITH HIPRES TRAVERSING THE ERN SEABOARD. RETURN FLOW THEN BRING ENOUGH HUMIDITY FOR PERHAPS A FEW ISOLD DIURNAL TSTMS...MAINLY ACROSS THE INTERIOR...WED. AS THE UPR RIDGE OVER THE PLAINS BUILDS WWD OVER THE 4 CORNERS...THIS WILL OPEN THE DOOR TO UPR LOWS DROPPING W OF THE CWA FOR THE END OF THE WEEK. THE RESULT WOULD BE INCREASING HUMIDITY AND CHANCES FOR PCPN WITH SW FLOW ALOFT. WRT SPECIFICS...THE 12Z GFS IS SIGNIFICANTLY DIFFERENT THAN THE 12Z ECMWF...WITH THE ECMWF MUCH SLOWER WITH THE ONSET OF ORGANIZED ACTIVITY OVER THE CWA. BECAUSE THE GFS TENDS TO OVER INITIATE CONVECTION AND THE ECMWF HAS A GOOD TRACK RECORD WITH THE DYNAMICS AT THE MEDIUM RANGE...WILL LEAN TOWARDS LWR POPS IN THE THU TIME PERIOD AND FOCUS THE POTENTIAL ON FRI INTO THE WEEKEND FOR NOW. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... A COLD FRONT WILL SLOWLY APPROACH FROM THE WEST TONIGHT AND WILL PASS TO THE EAST MONDAY MORNING. MAINLY VFR CONDITIONS WITH CIGS 3 TO 5 KFT FOR THE REMAINDER OF THE AFTERNOON...EXCEPT EASTERN TERMINALS WITH CIGS 2 TO 3 KFT. AN ISOLATED SHOWER OR THUNDERSTORM IS NOT OUT OF THE QUESTION THIS AFTERNOON...BUT WILL BE ISOLATED TO SCATTERED. LOOKS LIKE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE LATE AFTERNOON THROUGH THE EVENING HOURS. MVFR OR IFR CONDITIONS ARE ALWAYS POSSIBLE IN ANY HEAVIER STORMS. AFTER MIDNIGHT...THE FRONT APPROACHES NYC METRO WITH PERHAPS SOME LINGERING SHOWERS. THEN CONDITIONS WILL IMPROVE AFTER 08-11Z AS THE FRONT MOVES THROUGH. VFR BY MONDAY MORNING. STRONG SOUTHERLY WINDS OF 15 TO 20 KTS THROUGH THE AFTERNOON WILL LIGHTEN TO 10 TO 15 KTS BY EVENING. WINDS SLOWLY TURN TOWARD THE SOUTHWEST. THEN WINDS ABRUPTLY SHIFT TO THE NORTH/NORTHWEST BEHIND THE FRONT 08-11Z...FROM NW TO SOUTHEAST. WINDS BACK SLIGHTLY TO THE NORTHWEST MONDAY MORNING AROUND 10 TO 15 KT. OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY... .MONDAY AFTERNOON-WEDNESDAY...VFR. .THURSDAY-FRIDAY...MVFR OR LOWER POSSIBLE IN SCATTERED SHOWERS/TSTMS. && .MARINE... WINDS WILL GRADUALLY INCREASE THRU THIS EVE AS THE PRES GRAD TIGHTENS. WITH NEARSHORE MESONET DATA ALREADY COMING IN WITH THE LOW 20S...WILL ISSUE A SCA FOR TNGT FOR ALL BUT THE HARBOR. TSTMS WILL PRODUCE GUSTS IN EXCESS OF 30KT TNGT. WINDS DECREASE ACROSS ALL THE WATERS MON AFT THE WIND SHIFT BEHIND THE FRONT. THE SCA WILL NEED TO REMAIN UP FOR THE OCEAN WITH LINGERING SEAS. WINDS AND SEAS WILL THEN REMAIN BLW SCA LVL THRU MID WEEK WITH HIGH PRES OVER THE WATERS. SCA CONDITIONS MAY DEVELOP NEAR THE END OF THE WEEK. && .HYDROLOGY... THE FLASH FLOOD WATCH WILL REMAIN IN EFFECT TNGT. NO EXTENSION WAS MADE INTO THE ERN ZONES WITH FFG OVER 2 INCHES. THE THREAT IS NOT NON-ZERO HOWEVER...AND WILL CONTINUE TO BE MENTIONED IN THE HWO. ELSEWHERE...FFG IS LOWER AND THE THREAT FOR FLOODING REMAINS...MAINLY AS ORGANIZED CONVECTION TRACKS ACROSS THE CWA TNGT. PW/S AROUND 2.5 INCHES WILL POTENTIALLY YIELD RATES OF AROUND 2 INCHES/HR IN THE HEAVIEST TSTMS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR CTZ005-006-009. NY...FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR NYZ067>075- 176>179. NJ...FLASH FLOOD WATCH THROUGH MONDAY MORNING FOR NJZ002-004-006- 103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ330-335-340- 345. SMALL CRAFT ADVISORY UNTIL 2 PM EDT MONDAY FOR ANZ355. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ350-353. && $$ SYNOPSIS...JMC NEAR TERM...JMC SHORT TERM...JMC LONG TERM...JMC AVIATION...PW MARINE...JMC HYDROLOGY...JMC
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
516 PM EDT SUN AUG 5 2012 .SYNOPSIS... A COLD FRONT, CROSSING THE AREA THIS EVENING, WILL BRING A DAMP END TO OUR WEEKEND. HIGH PRESSURE WILL BUILD OVERHEAD FOR THE BEGINNING OF THE WORK WEEK. TEMPERATURES ARE PREDICTED TO REMAIN AT SEASONAL LEVELS UNTIL THE END OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... HAVE UPDATED THE POPS TO DEPICT BACK EDGE OF SHOWERS/STORMS. HAVE ALSO MADE MINOR ADJUSTMENTS TO CLOUD COVER AND TEMPS. PREVIOUS DISCUSSION... RESIDUAL CLOUD COVER FROM THIS MORNING/EARLY AFTERNOON THUNDERSTORMS HAS STABILIZED A GOOD PART OF THE AREA. HOWEVER...AS IS ALREADY BEING DEPICTED OVER CENTRAL OHIO AND SOUTHEASTERN INDIANA...BREAKS IN THE CLOUDS MAY ALLOW FOR ENOUGH HEATING AND DESTABILIZATION TO FIRE ANOTHER LINE OF THUNDERSTORMS ALONG AND JUST AHEAD OF THE COLD FRONT AS IT SWINGS ACROSS. SURFACE CAPE VALUES HAVE ALREADY REBOUNDED TO NEAR 1000 J/KG OVER OHIO ACCORDING TO THE SPC MESOANALYSIS AND THERE CONTINUES TO BE AMPLE LOW LEVEL MOISTURE WITH MUCH OF THE AREA EXPERIENCING DEWPOINTS OF 70+. WHILE MOST OF THE BETTER UPPER LEVEL SUPPORT AND SHEAR WILL REMAIN NORTH...WEAK BULK SHEAR OF 30KTS COULD ALLOW FOR SOME STORMS TO SUPPORT THEMSELVES TO SEVERE LEVELS. THE OTHER CONCERN WILL CONTINUE TO BE HEAVY RAINFALL. PWAT VALUES OVER 2 INCHES AND HIGH THETA-E VALUES WILL SUPPORT HEAVY DOWNPOURS. WHILE THE FRONT SHOULD BE FAIRLY PROGRESSIVE...TRAINING STORMS OVER AREAS THAT ALREADY RECEIVED ALMOST AN INCH OF RAINFALL COULD POSE A PROBLEM. THIS WAS JUSTIFICATION TO KEEP LIKELY AND CATEGORICAL POPS THROUGH THIS EVENING. THE COLD FRONT IS EXPECTED TO CROSS THE REGION BY LATE TONIGHT/MONDAY MORNING. MAY END UP BEING A LITTLE TOO SLOW WITH THE REMOVAL OF POPS OVERNIGHT PER THE MOST RECENT HRRR MODEL OUTPUT BUT WILL LEAVE AS IS FOR NOW. HIGH PRESSURE WILL BUILD OVER THE REGION FOR MONDAY BRINGING DRIER AIR AND TEMPERATURES CLOSER TO NORMAL. KEPT CLOSE TO LAMP/MAV GUIDANCE WITH HIGHS AND LOWS TONIGHT AND MONDAY. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL REMAIN THE MAIN STORY THROUGH MOST OF WEDNESDAY. WITH STRONG SUBSIDENCE AND RADIATIVE COOLING...TEMPERATURES OVERNIGHT MONDAY AND TUESDAY COULD BE BELOW NORMAL AND INTO THE 50`S. THIS IS CLOSEST TO MAV GUIDANCE THROUGH THE PERIOD. MODELS ARE IN DISAGREEMENT ON THE APPROACH OF THE NEXT SYSTEM WITH THE NAM BRINGING A FRONTAL BOUNDARY/SHORTWAVE ACROSS THE REGION LATE WEDNESDAY. THIS IS QUICKER THAN THE GFS. AT THIS POINT...WILL JUST HEDGE WITH SLIGHT CHANCE POPS WITH THE TIMING INCONSISTENCIES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO MAJOR CHANGES TO EXTENDED FORECAST CONSIDERING FOCUS WAS ON POSSIBLE SEVERE WEATHER FOR TODAY. MODELS STILL NOT SHOWING MUCH AGREEMENT ON FRONTAL PASSAGE FOR END OF THE WORK WEEK. 12Z GFS BRINGS FRONT THROUGH ON THURSDAY...00Z ECMWF BRINGS FRONT THROUGH ON THURSDAY/FRIDAY...AND 00Z GEFS BRINGS FRONT THROUGH ON FRIDAY. AT THIS POINT...HAVE STUCK CLOSE TO PREVIOUS FORECAST...WHICH BRINGS FRONT THROUGH ON FRIDAY. TEMPERATURES WILL TURN COOLER FOR THE WEEKEND...WITH HIGHS DROPPING INTO THE 70S. AN ISOLATED SHOWER CANNOT BE RULED OUT OVER THE WEEKEND WITH RELATIVELY COOLER 850MB AIR (10-12C) PASSING OVER A WARM LAKE ERIE (23-25C). && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... LOW CONFIDENCE FOR THIS TAF ISSUANCE...AS GUIDANCE SEEMS TO BE OF NEARLY NO VALUE IN THE SHORT TERM. WIDESPREAD RAIN HAS MOVED EAST OF THE AREA MORE QUICKLY THAN ANTICIPATED...AND AM STILL TRYING TO DETERMINE WHAT WILL HAPPEN IN THE WAKE OF THE PRECIPITATION. ALTHOUGH IMMEDIATELY AFTER RAIN COMES TO AN END SOME TERMINALS MAY BRIEFLY GO VFR...UPSTREAM TRENDS INDICATE THAT MOST TERMINALS WILL DROP BACK TO MVFR IN LOWER CEILINGS. WITH THE ACTUAL COLD FRONT REMAINING TO THE WEST...ISOLATED/SCATTERED SHOWERS/STORMS CANNOT BE RULED OUT DURING THE AFTERNOON HOURS. AFTER FRONT MOVES THROUGH...WINDS WILL SHIFT TO THE WEST AND SOME CLEARING IS POSSIBLE FOR THE EVENING HOURS. WITH ABUNDANT SURFACE MOISTURE IN PLACE FROM TODAY`S RAINFALL, FOG IS EXPECTED TO DEVELOP DURING THE PRE-DAWN HOURS ON MONDAY. HAVE EXPANDED COVERAGE OF IFR FORECASTS CONSIDERING MOST LOCATIONS SAW AT LEAST A QUARTER INCH OF RAIN. ALTHOUGH DUJ...LBE...AND MGW ARE THE APPARENT EXCEPTIONS TO HEAVIER RAINFALL...IFR CONDITIONS CANNOT BE RULED OUT IN THESE LOCATIONS EITHER. FOG WILL BREAK BY MID MORNING...WITH LIGHT NORTHWEST WINDS EXPECTED. OUTLOOK...MONDAY THROUGH FRIDAY... VFR CONDITIONS WILL MOSTLY PREVAIL THROUGH WEDNESDAY AS HIGH PRESSURE CROSSES THE OHIO VALLEY. LOW PRESSURE MOVING INTO THE GREAT LAKES WILL RETURN THE CHANCE OF THUNDERSTORMS BY THE END OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
303 PM EDT SUN AUG 5 2012 .SYNOPSIS... A COLD FRONT CROSSING THE AREA THIS EVENING WILL BRING A DAMP END TO OUR WEEKEND. HIGH PRESSURE WILL BUILD OVERHEAD FOR THE BEGINNING OF THE WORK WEEK. TEMPERATURES ARE PREDICTED TO REMAIN AT SEASONAL LEVELS UNTIL THE END OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... RESIDUAL CLOUD COVER FROM THIS MORNING/EARLY AFTERNOON THUNDERSTORMS HAS STABILIZED A GOOD PART OF THE AREA. HOWEVER...AS IS ALREADY BEING DEPICTED OVER CENTRAL OHIO AND SOUTHEASTERN INDIANA...BREAKS IN THE CLOUDS MAY ALLOW FOR ENOUGH HEATING AND DESTABILIZATION TO FIRE ANOTHER LINE OF THUNDERSTORMS ALONG AND JUST AHEAD OF THE COLD FRONT AS IT SWINGS ACROSS. SURFACE CAPE VALUES HAVE ALREADY REBOUNDED TO NEAR 1000 J/KG OVER OHIO ACCORDING TO THE SPC MESOANALYSIS AND THERE CONTINUES TO BE AMPLE LOW LEVEL MOISTURE WITH MUCH OF THE AREA EXPERIENCING DEWPOINTS OF 70+. WHILE MOST OF THE BETTER UPPER LEVEL SUPPORT AND SHEAR WILL REMAIN NORTH...WEAK BULK SHEAR OF 30KTS COULD ALLOW FOR SOME STORMS TO SUPPORT THEMSELVES TO SEVERE LEVELS. THE OTHER CONCERN WILL CONTINUE TO BE HEAVY RAINFALL. PWAT VALUES OVER 2 INCHES AND HIGH THETA-E VALUES WILL SUPPORT HEAVY DOWNPOURS. WHILE THE FRONT SHOULD BE FAIRLY PROGRESSIVE...TRAINING STORMS OVER AREAS THAT ALREADY RECEIVED ALMOST AN INCH OF RAINFALL COULD POSE A PROBLEM. THIS WAS JUSTIFICATION TO KEEP LIKELY AND CATEGORICAL POPS THROUGH THIS EVENING. THE COLD FRONT IS EXPECTED TO CROSS THE REGION BY LATE TONIGHT/MONDAY MORNING. MAY END UP BEING A LITTLE TOO SLOW WITH THE REMOVAL OF POPS OVERNIGHT PER THE MOST RECENT HRRR MODEL OUTPUT BUT WILL LEAVE AS IS FOR NOW. HIGH PRESSURE WILL BUILD OVER THE REGION FOR MONDAY BRINGING DRIER AIR AND TEMPERATURES CLOSER TO NORMAL. KEPT CLOSE TO LAMP/MAV GUIDANCE WITH HIGHS AND LOWS TONIGHT AND MONDAY. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL REMAIN THE MAIN STORY THROUGH MOST OF WEDNESDAY. WITH STRONG SUBSIDENCE AND RADIATIVE COOLING...TEMPERATURES OVERNIGHT MONDAY AND TUESDAY COULD BE BELOW NORMAL AND INTO THE 50`S. THIS IS CLOSEST TO MAV GUIDANCE THROUGH THE PERIOD. MODELS ARE IN DISAGREEMENT ON THE APPROACH OF THE NEXT SYSTEM WITH THE NAM BRINGING A FRONTAL BOUNDARY/SHORTWAVE ACROSS THE REGION LATE WEDNESDAY. THIS IS QUICKER THAN THE GFS. AT THIS POINT...WILL JUST HEDGE WITH SLIGHT CHANCE POPS WITH THE TIMING INCONSISTENCIES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... NO MAJOR CHANGES TO EXTENDED FORECAST CONSIDERING FOCUS WAS ON POSSIBLE SEVERE WEATHER FOR TODAY. MODELS STILL NOT SHOWING MUCH AGREEMENT ON FRONTAL PASSAGE FOR END OF THE WORK WEEK. 12Z GFS BRINGS FRONT THROUGH ON THURSDAY...00Z ECMWF BRINGS FRONT THROUGH ON THURSDAY/FRIDAY...AND 00Z GEFS BRINGS FRONT THROUGH ON FRIDAY. AT THIS POINT...HAVE STUCK CLOSE TO PREVIOUS FORECAST...WHICH BRINGS FRONT THROUGH ON FRIDAY. TEMPERATURES WILL TURN COOLER FOR THE WEEKEND...WITH HIGHS DROPPING INTO THE 70S. AN ISOLATED SHOWER CANNOT BE RULED OUT OVER THE WEEKEND WITH RELATIVELY COOLER 850MB AIR (10-12C) PASSING OVER A WARM LAKE ERIE (23-25C). && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... LOW CONFIDENCE FOR THIS TAF ISSUANCE...AS GUIDANCE SEEMS TO BE OF NEARLY NO VALUE IN THE SHORT TERM. WIDESPREAD RAIN HAS MOVED EAST OF THE AREA MORE QUICKLY THAN ANTICIPATED...AND AM STILL TRYING TO DETERMINE WHAT WILL HAPPEN IN THE WAKE OF THE PRECIPITATION. ALTHOUGH IMMEDIATELY AFTER RAIN COMES TO AN END SOME TERMINALS MAY BRIEFLY GO VFR...UPSTREAM TRENDS INDICATE THAT MOST TERMINALS WILL DROP BACK TO MVFR IN LOWER CEILINGS. WITH THE ACTUAL COLD FRONT REMAINING TO THE WEST...ISOLATED/SCATTERED SHOWERS/STORMS CANNOT BE RULED OUT DURING THE AFTERNOON HOURS. AFTER FRONT MOVES THROUGH...WINDS WILL SHIFT TO THE WEST AND SOME CLEARING IS POSSIBLE FOR THE EVENING HOURS. WITH ABUNDANT SURFACE MOISTURE IN PLACE FROM TODAY`S RAINFALL, FOG IS EXPECTED TO DEVELOP DURING THE PRE-DAWN HOURS ON MONDAY. HAVE EXPANDED COVERAGE OF IFR FORECASTS CONSIDERING MOST LOCATIONS SAW AT LEAST A QUARTER INCH OF RAIN. ALTHOUGH DUJ...LBE...AND MGW ARE THE APPARENT EXCEPTIONS TO HEAVIER RAINFALL...IFR CONDITIONS CANNOT BE RULED OUT IN THESE LOCATIONS EITHER. FOG WILL BREAK BY MID MORNING...WITH LIGHT NORTHWEST WINDS EXPECTED. OUTLOOK...MONDAY THROUGH FRIDAY... VFR CONDITIONS WILL MOSTLY PREVAIL THROUGH WEDNESDAY AS HIGH PRESSURE CROSSES THE OHIO VALLEY. LOW PRESSURE MOVING INTO THE GREAT LAKES WILL RETURN THE CHANCE OF THUNDERSTORMS BY THE END OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1158 AM CDT SUN AUG 5 2012 .UPDATE... ISSUED AT 1059 AM CDT SUN AUG 5 2012 QUICK UPDATE MAINLY FOR CLOUDS AND POPS. WITH THE CDFNT SLOWLY SINKING SWWD...CLOUDS SHUD GRADUALLY CLEAR OUT N TO S. LATEST MDLS SUGGEST SHRA/TSRA REDEVELOPING ALONG OR JUST S OF THE CWA. HAVE KEPT POPS FOR MID TO LATE THIS AFTERNOON TO ACCOUNT FOR THIS REDEVELOPMENT...BUT WITH THE BEST CHANCES FURTHER S...WILL KEEP ONLY SLIGHT CHANCES GOING FOR NOW. WILL CONTINUE TO MONITOR AND UPDATE AS NEEDED. THE REMAINDER OF THE FORECAST APPEARS TO BE ON TRACK ATTM. TILLY && .SHORT TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (TODAY AND TONIGHT) FOCUS INITIALLY WILL BE ON EXITING THUNDERSTORMS. LATEST RUNS OF THE RAP SEEM TO BE IN LINE WITH CURRENT EXTRAPOLATION THAT SURFACE FRONT WILL BE RIGHT ALONG THE SOUTHERN BORDER OF THE CWA AT 12Z. AXIS OF SHORTWAVE TROUGH CURRENTLY ALONG THE KS/MO BORDER WILL BE OVER SOUTHEASTERN MO WITH SOME LINGER 925-850 ALONG AND JUST NORTH OF THE SFC FRONT. HAVE ISOLATED/SCATTERED THUNDERSTORMS SLOWLY PUSHING SOUTH OF THE CWA BETWEEN 12-18Z BEFORE SUBSIDENCE SETS IN BEHIND THE SHORTWAVE. CLOUDS WILL ALSO DECREASE THROUGH MIDDAY AS LOW-MID LEVEL MOISTURE AND CONVECTIVE DEBRIS MOVES OUT OF THE AREA. STAYED WITH THE BETTER VERIFYING NAM MOS HIGHS TODAY...PARTICULARLY WHERE THERE SHOULD BE THE MOST SUN. SKIES WILL BE CLEAR TONIGHT AND WINDS SHOULD TURN LIGHT EASTERLY BY MORNING AS SURFACE HIGH CENTER PASSES THROUGH NORTHERN MO/CENTRAL IL. CAN`T RULE OUT SOME FOG DEVELOPING IN AREAS THAT HAD THE HEAVIEST RAINFALL THE PAST 24 HOURS LATE TONIGHT/EARLY MONDAY. BRITT && .LONG TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (MONDAY THROUGH SATURDAY) DRY WEATHER WILL BE THE RULE MONDAY AND TUESDAY AS LOW LEVEL MOISTURE WILL BE CUT OFF BY FRONT MOVING THROUGH TODAY AND AREA WILL BE UNDER MAINLY SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT. NAM/GFS BOTH SHOW A TROUGH MOVING ACROSS THE MIDWEST ON TUESDAY...BUT THE BEST ASCENT WILL STAY TO THE NORTH OF THE AREA AS IT BEGINS TO SHEAR OUT. STAYED CLOSER TO THE NAM MOS FOR HIGHS AS FORECAST SOUNDINGS ARE SHOWING MIXING UP TO 800MB ON MONDAY AND 700MB ON TUESDAY. LOWER 90S SEEM REASONABLE ON MONDAY WITH 850MB TEMPS NEAR 20C...AS DO MIDDLE TO POSSIBLY UPPER 90S ON TUESDAY WITH 20-24C 850MB TEMPS. DOES LOOK LIKE DEWPOINTS WILL STAY IN THE 50S DURING THE PERIOD WHICH SHOULD KEEP HEAT INDEX READINGS AT OR BELOW THE AMBIENT TEMPERATURES. THE GFS IS SHOWING A DEEPER TROUGH DIGGING IN OVER THE MISSISSIPPI VALLEY ON THURSDAY THAN IT DID PREVIOUSLY. ECMWF/CANADIAN GEM SHOW A LESS AMPLIFIED AND SLOWER SOLUTION...SO GOING SLIGHT CHANCES FOR THUNDERSTORMS SEEM THE BEST ROUTE. THEN GFS IS SHOWING ANOTHER SORTHWAVE MOVING DOWN TOWARD THE AREA BY EARLY NEXT WEEKEND WITH THE ECMWF HAVING A SLOWER SOLUTION...SO AGAIN SLIGHT CHANCES SEEM THE BEST ROUTE. 850MB TEMPS ARE SHOWING A SLOW DECLINE FROM WEDNESDAY TO SATURDAY AS 500MB HEIGHTS SLOWLY FALL WITH THE PASSAGE OF THE SHORTWAVES...SO HAVE TEMPERATURES FALLING FROM THE LOWER-MID 90S ON THURSDAY INTO MAINLY IN THE 80S ON SATURDAY. BRITT && .AVIATION... ISSUED AT 1134 AM CDT SUN AUG 5 2012 VFR AND DRY THRU THE TAF PERIOD EXCEPT FOR KSUS...SEE BELOW. NLY WINDS AROUND 10KTS BECOMING LIGHT AND VRB THIS EVENING AND REMAINING SO THRU MON MORNING AS SFC RIDGE SETTLES IN ACROSS THE REGION. FOR KSUS...OTHER THAN WHAT IS MENTIONED ABOVE...WITH WINDS BECOMING LIGHT TO CALM AND CLEAR SKIES...GOOD RADIATIONAL COOLING SHUD OCCUR. THIS MAY ALLOW FG TO FORM LATE TONIGHT. BELIEVE THERE WILL BE ENUF DRY AIR ADVECTING IN TO PREVENT THIS FROM DEVELOPING...BUT CONFIDENCE IS TOO LOW TO REMOVE FROM TAF ATTM. TILLY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1111 AM CDT SUN AUG 5 2012 .UPDATE... ISSUED AT 1059 AM CDT SUN AUG 5 2012 QUICK UPDATE MAINLY FOR CLOUDS AND POPS. WITH THE CDFNT SLOWLY SINKING SWWD...CLOUDS SHUD GRADUALLY CLEAR OUT N TO S. LATEST MDLS SUGGEST SHRA/TSRA REDEVELOPING ALONG OR JUST S OF THE CWA. HAVE KEPT POPS FOR MID TO LATE THIS AFTERNOON TO ACCOUNT FOR THIS REDEVELOPMENT...BUT WITH THE BEST CHANCES FURTHER S...WILL KEEP ONLY SLIGHT CHANCES GOING FOR NOW. WILL CONTINUE TO MONITOR AND UPDATE AS NEEDED. THE REMAINDER OF THE FORECAST APPEARS TO BE ON TRACK ATTM. TILLY && .SHORT TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (TODAY AND TONIGHT) FOCUS INITIALLY WILL BE ON EXITING THUNDERSTORMS. LATEST RUNS OF THE RAP SEEM TO BE IN LINE WITH CURRENT EXTRAPOLATION THAT SURFACE FRONT WILL BE RIGHT ALONG THE SOUTHERN BORDER OF THE CWA AT 12Z. AXIS OF SHORTWAVE TROUGH CURRENTLY ALONG THE KS/MO BORDER WILL BE OVER SOUTHEASTERN MO WITH SOME LINGER 925-850 ALONG AND JUST NORTH OF THE SFC FRONT. HAVE ISOLATED/SCATTERED THUNDERSTORMS SLOWLY PUSHING SOUTH OF THE CWA BETWEEN 12-18Z BEFORE SUBSIDENCE SETS IN BEHIND THE SHORTWAVE. CLOUDS WILL ALSO DECREASE THROUGH MIDDAY AS LOW-MID LEVEL MOISTURE AND CONVECTIVE DEBRIS MOVES OUT OF THE AREA. STAYED WITH THE BETTER VERIFYING NAM MOS HIGHS TODAY...PARTICULARLY WHERE THERE SHOULD BE THE MOST SUN. SKIES WILL BE CLEAR TONIGHT AND WINDS SHOULD TURN LIGHT EASTERLY BY MORNING AS SURFACE HIGH CENTER PASSES THROUGH NORTHERN MO/CENTRAL IL. CAN`T RULE OUT SOME FOG DEVELOPING IN AREAS THAT HAD THE HEAVIEST RAINFALL THE PAST 24 HOURS LATE TONIGHT/EARLY MONDAY. BRITT && .LONG TERM... ISSUED AT 248 AM CDT SUN AUG 5 2012 (MONDAY THROUGH SATURDAY) DRY WEATHER WILL BE THE RULE MONDAY AND TUESDAY AS LOW LEVEL MOISTURE WILL BE CUT OFF BY FRONT MOVING THROUGH TODAY AND AREA WILL BE UNDER MAINLY SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT. NAM/GFS BOTH SHOW A TROUGH MOVING ACROSS THE MIDWEST ON TUESDAY...BUT THE BEST ASCENT WILL STAY TO THE NORTH OF THE AREA AS IT BEGINS TO SHEAR OUT. STAYED CLOSER TO THE NAM MOS FOR HIGHS AS FORECAST SOUNDINGS ARE SHOWING MIXING UP TO 800MB ON MONDAY AND 700MB ON TUESDAY. LOWER 90S SEEM REASONABLE ON MONDAY WITH 850MB TEMPS NEAR 20C...AS DO MIDDLE TO POSSIBLY UPPER 90S ON TUESDAY WITH 20-24C 850MB TEMPS. DOES LOOK LIKE DEWPOINTS WILL STAY IN THE 50S DURING THE PERIOD WHICH SHOULD KEEP HEAT INDEX READINGS AT OR BELOW THE AMBIENT TEMPERATURES. THE GFS IS SHOWING A DEEPER TROUGH DIGGING IN OVER THE MISSISSIPPI VALLEY ON THURSDAY THAN IT DID PREVIOUSLY. ECMWF/CANADIAN GEM SHOW A LESS AMPLIFIED AND SLOWER SOLUTION...SO GOING SLIGHT CHANCES FOR THUNDERSTORMS SEEM THE BEST ROUTE. THEN GFS IS SHOWING ANOTHER SORTHWAVE MOVING DOWN TOWARD THE AREA BY EARLY NEXT WEEKEND WITH THE ECMWF HAVING A SLOWER SOLUTION...SO AGAIN SLIGHT CHANCES SEEM THE BEST ROUTE. 850MB TEMPS ARE SHOWING A SLOW DECLINE FROM WEDNESDAY TO SATURDAY AS 500MB HEIGHTS SLOWLY FALL WITH THE PASSAGE OF THE SHORTWAVES...SO HAVE TEMPERATURES FALLING FROM THE LOWER-MID 90S ON THURSDAY INTO MAINLY IN THE 80S ON SATURDAY. BRITT && .AVIATION... ISSUED AT 552 AM CDT SUN AUG 5 2012 COLD FRONT HAS PASSED JUST S OF COU AND STL EARLY THIS MRNG. MOST OF THE CONVECTION HAS SHIFTED S OF THE TAF SITES...ALTHOUGH COULD NOT RULE OUT AN ISOLATED SHOWER TIL 14Z SUN FROM COU TO STL. WILL LEAVE THE TAFS DRY AS THE PROBABILITY OF ANY MORE RAIN IS QUITE LOW. BAND OF LOW LEVEL CLOUDS ALONG AND JUST BEHIND THE FRONT FROM 1500-3000 FT IN HEIGHT SHOULD ADVECT SE OF THE STL METRO AREA BY 14-15Z SUN WITH LINGERING VFR LOW-MID LEVEL CLOUD COVER FROM COU TO STL AREA FOR THE REST OF THE MRNG...THEN MAINLY JUST HIGH LEVEL CLOUDS CLEARING OUT FROM NW TO SE THIS AFTN. N-NWLY SFC WIND WILL BECOME LIGHT THIS EVNG AS THE SFC RIDGE OVER THE PLAINS SHIFTS EWD TO NRN IL TGT. THERE MAY BE SOME FOG LATE TGT ESPECIALLY FOR SUS DUE TO RECENT RAINFALL ALONG WITH A CLEAR SKY AND LIGHT SFC WIND. SPECIFICS FOR KSTL...LOW LEVEL CLOUD CEILING AROUND 3000 FT SHOULD RISE IN HEIGHT LATER THIS MRNG WITH MAINLY JUST HIGH LEVEL CLOUDS THIS AFTN. NWLY SFC WIND SHOULD INCREASE TO AROUND 10 KTS LATER THIS MRNG FROM A N-NWLY DIRECTION AS A SFC RIDGE BUILDS SEWD INTO OUR AREA BEHIND THE COLD FRONT. THE SFC WIND SHOULD BECOME LIGHT THIS EVNG WITH THE SFC HIGH CENTERED JUST NE OF STL BY 12Z MON. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
620 PM EDT SUN AUG 5 2012 .SYNOPSIS... A COLD FRONT WILL PUSH ACROSS NORTHWESTERN PENNSYLVANIA THIS EVENING...AND THROUGH THE REMAINDER OF THE COMMONWEALTH OVERNIGHT. HIGH PRESSURE WILL BUILD INTO THE STATE LATER MONDAY BEFORE BECOMING CENTERED OVER THE REGION MONDAY NIGHT. NOTICEABLY LOWER HUMIDITY AND NEAR NORMAL TEMPERATURES WILL OCCUR DURING THE FIRST HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... RECENTLY CANCELLED SVR TSTM WATCH 564 FOR THE SEVERAL COUNTIES IN THE SERN PART OF OUR CWA. SFC COLD FRONT NEARING THE SOUTH SHORE OF LAKE ERIE AT 22Z. SOME SIGNIFICANT BREAKS IN THE CLOUD COVER AND HAS LED TO A RECOVERY OF THE ATMOS TO MDT INSTABILITY ACROSS SWRN PENN WITH MU CAPES OF AROUND 2000 J/KG...AND SEVERAL BANDS OF MDTLY STRONG 925-850 MB THETA-E CONVERGENCE /FCST BY THE 21Z RUC FOR THIS EVENING/ HELPING TO SPARK A BKN LINE OF LOW-TOPPED SHRA/TSRA FROM NEAR KDUJ...SW TO KAGC...AND A WEAKER LINE OF SHRA NEAR KBFD. ISOLATED TO SCATTERED SHRA/TSRA WILL DRIFT GRADUALLY EAST ACROSS THE FCST AREA EARLY TONIGHT...ALONG AND AHEAD OF THE COLD FRONT. A FEW OF THE TSRA ACROSS OUR SOUTHERN ZONES COULD GROW TALL ENOUGH TO MAKE SOME SMALL HAIL AND PERHAPS BRING A BRIEF WIND GUST OF 30-40 MPH...BUT LITTLE CHC FOR THE CONVECTION REACHING SEVERE CRITERIA AS THE HEATING/SUN WEAKENS. SCATTERED SHOWERS AND ISOLATED TSRA SHOULD DIMINISH AFTER MIDNIGHT...FOLLOWED BY WHAT MIGHT BE SHORT-LIVED CLEARING IF THE RAIN KEEPS BLYR MOISTURE HIGH. BUT ENOUGH PRE-SUNSET DRYING WILL ACT TO BALANCE THIS POTENTIAL TROUBLE. WILL JUST GO P/CLDY FOR MOST OF THE NIGHT...WITH HIGHER SKY COVER NUMBERS IN THE GRIDS ACROSS THE S. MIN TEMPS WILL RANGE FROM THE U50S NW WHERE DRIER AIR INFILRATES...TO AROUND 70F IN THE SE. && .SHORT TERM /MONDAY/... MONDAY WILL FEATURE DRYING OVER THE AREA AS HIGH PRESSURE SLIDES IN FROM THE WEST. MORNING FOG OR STRATUS WILL BURN OFF QUICKLY. TEMPS SHOULD REBOUND NORMAL IN MANY AREAS THANKS TO THE SUNSHINE. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... CENTER OF SFC HIGH SETTLES OVER PA MON NIGHT/TUE BRINGING A DRY FIRST HALF OF THE NEW WEEK. THOUGH NW-W FLOW ALOFT CONTINUES MUCH OF THE WEEK...A WEAK BOUNDARY SETS UP OFF THE ATLANTIC COAST MIDWEEK - NUDGING LOW LEVEL MOISTURE BACK INTO EASTERN PORTION OF CWA. SO KEPT MENTION OF SLIGHT CHANCE FOR A TSTM WED/THU AS HUMIDITY SLOWLY INCREASES. MORE POTENT TROUGH APPROACHES IN NW FLOW FOR THU NIGHT-FRI NIGHT. MODELS HANDLING THIS FEATURE WELL...THOUGH GFS STILL TRIES TO LIFT TROUGH NORTHWARD. EITHER WAY...MOISTURE CONTINUES TO SLOWLY INCREASE AS FLOW TURNS SW AHEAD OF TROUGH. CHANCE/SCATTERED SHOWERS/TSTMS FITS THE BILL BEFORE JUST ISOLATED CONVECTION POSS THIS WEEKEND. AFTER A COOL NIGHT MON NIGHT...TEMPERATURES WILL GRADUALLY RISE SLIGHTLY ABOVE NORMAL FOR MIDWEEK. HUMIDITY INCREASES LATE WEEK AHEAD OF APPROACHING TROUGH...MAKING IT FEEL MORE MUGGY. THEN TEMPS COOL BACK DOWN FOR NEXT WEEKEND. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... MVFR OVER THE WRN TAFS WILL CONTINUE FOR THE NEXT FEW HRS...AS DRIER AIR BEHIND THE FRONT IS STILL QUITE A FEW HRS AWAY. HEATING FROM STRONG SUNSHINE HAS DEVELOPED STRONG/SEVERE THUNDERSTORMS IN THE CENTRAL COS WHICH HAVE MOVED TO THE EAST STEADILY. BRIEF REDUCTIONS TO MVFR A COLD FRONT WILL OCCUR AT KMDT/KLNS - BUT MOST OF THE REST OF THE PERIOD SHOULD BE VFR OR MVFR AT WORST WITH ONLY ISOLD/SCT SHRA. IT COULD TAKE UNTIL AT LEAST 06Z TO PUSH THE LAST OF THE SHRA SSOCD WITH THE FRONT THROUGH THE SERN TERMINALS. FOG AND LOW CLOUDS ARE POSSIBLE LATER TONIGHT AFTER THE FROPA. MON SEEMS VFR AFTER ANY EARLY FOG/STRATUS. OUTLOOK... .TUE-THU...NO SIG WX. .FRI...TSRA/SHRA POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/LAMBERT NEAR TERM...LAMBERT SHORT TERM...DANGELO LONG TERM...LAMBERT/RXR AVIATION...DANGELO