Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/24/13


AREA FORECAST DISCUSSION
NWS NEW YORK NY
435 PM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN MOVE INTO WESTERN PORTIONS OF THE TRI-STATE THURSDAY NIGHT. A WAVE OF LOW PRESSURE DEVELOPS ALONG THIS SLOW MOVING COLD FRONT FRIDAY...REMAINS JUST EAST OF THE REGION SATURDAY...AND THEN TRACKS NORTH ALONG THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE OVER THE GREAT LAKES BUILDS SOUTHEAST ACROSS THE AREA MONDAY INTO TUESDAY. A WARM FRONT WILL THEN APPROACH FROM THE SOUTHWEST BY MID WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... WEAK FRONTAL BOUNDARY REMAINS STALLED JUST TO THE W AND S OF THE AREA...WITH A MARINE AIRMASS REMAINING IN PLACE. THIS FRONT SHOULD NOT MOVE MUCH...IF AT ALL TONIGHT...SO WOULD EXPECT MOST IF NOT ALL PRECIPITATION TO GO N OF THE AREA. THIS IS CONSISTENT WITH THE HRRR AND RAP...WHICH HAVE HAD THE BEST HANDLE ON THIS FRONT AND THE WEATHER TODAY BY FAR...ALONG WITH THE NAM AND SREF. BASED ON THIS HAVE GONE BASICALLY DRY ACROSS THE S 2/3 OF THE CWA THIS EVENING...WITH SLIGHT CHANCE POPS FAR N TIER...THEN SLIGHT CHANCE POPS THROUGHOUT OVERNIGHT IN RESPONSE TO AN APPROACHING 700-500 HPA SHORTWAVE. WITH MARINE LAYER INTACT - WOULD EXPECT LOW CLOUD DECK TO RE- ESTABLISH ITSELF ACROSS THE AREA OVERNIGHT. COULD SEE PATCHY FOG AS WELL - POSSIBLY LOCALLY DENSE NEAR THE ATLANTIC COAST. FOR LOWS USED A BLEND OF 50 PERCENT MAV GUIDANCE WITH 25 PERCENT MET GUIDANCE AND 25 PERCENT NAM 2-METER TEMPERATURES. FORECASTING LOWS 10-15 DEGREES ABOVE NORMAL. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... MIXING ASSOCIATED WITH PASSING 700-500 HPA SHORTWAVE THURSDAY MORNING SHOULD ERODE THE MARINE INVERSION - BUT STILL WILL BE LEFT WITH QUITE A BIT OF MID TO HIGH CLOUDS WITH MOIST SW FLOW ALOFT. PRE-FRONTAL TROUGH MOVING INTO THE LOWER HUDSON VALLEY/NE NJ THURSDAY AFTERNOON SHOULD SERVE AS TRIGGER FOR SCT-NUMEROUS SHRA WITH EMBEDDED TSRA. LIKELY POPS MAINLY FROM NYC-INTERIOR SW CT ZONES ON W AND CHANCE POPS EAST OF THAT LINE. SOME SUGGESTION FROM NAM/GFS THAT EASTERN AREAS WILL REMAIN DRY THURSDAY...BUT FOR NOW TOO MUCH LOW-MID LEVEL MOISTURE AND INCREASING LOW LEVEL JET TO FORECAST THAT AT THIS TIME. WITH 30-35 KT BULK SHEAR...1000-1500 J/KG OF CAPE AND BULK RICHARDSON NUMBERS 15-30 HAVE THE POTENTIAL FOR ISOLATED SEVERE STORMS THURSDAY AFTERNOON ACROSS NE NJ/LOWER HUDSON VALLEY AND MAYBE NYC AND SW CT ZONES. MAIN THREAT IS GUSTY WINDS AND LARGE HAIL. ALSO NEED TO WATCH FOR LOW LEVEL HELICITY WITH S SFC FLOW AND SW FLOW AT 850 HPA. FOR HIGHS THURSDAY USED A BLEND OF MIXING DOWN FROM 975 HPA NEAR THE COAST AND 950 HPA INLAND...WITH NAM 2-METER TEMPERATURES AND A BLEND OF MAV AND MET GUIDANCE. FORECASTING VALUES AROUND NORMAL EAST TO A FEW DEGREES ABOVE NORMAL WEST. DEEP SW FLOW ALOFT...BECOMES DIFFLUENT AT 500 HPA AFTER MIDNIGHT. HAVE THE POTENTIAL FOR HEAVY RAINFALL AS A RESULT. REFER TO THE HYDROLOGY SECTION FOR DETAILS. SEVERE THREAT COULD LINGER INTO THE EVENING ACROSS WESTERN ZONES AS WELL. FOR LOWS THURSDAY NIGHT USED A BLEND OF MAV/MET GUIDANCE WITH VALUES FORECAST AROUND 10 DEGREES ABOVE NORMAL. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... MODELS HAVE TRENDED CONSIDERABLY SLOWER AND DEEPER WITH THE APPROACHING UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY. THERE IS VERY GOOD AGREEMENT WITH THE 12Z GFS AND ECMWF ON TAKING A CLOSED UPPER LOW FROM THE MID ATLANTIC STATES ON FRI NE TO OVER NEW ENGLAND ON SUN. THE NAM AND GGEM ARE TRENDING IN THAT DIRECTION...BUT ARE MORE PROGRESSIVE BEYOND 00Z SAT. PREFERENCE AT THIS TIME IS TO GO WITH THE SLOWER GFS/ECMWF SOLUTION BASED ON MODEL TRENDS AND THE RUN TO RUN CONTINUITY BEING EXHIBITED OVER THE LAST SEVERAL MODEL CYCLES. AS FOR SENSIBLE WEATHER...THIS RESULTS IN A WET...COOL WEEKEND WITH THE POTENTIAL FOR ANOTHER 1 TO 2 INCHES OF RAINFALL IN THE FRI-SAT TIME FRAME. SINCE THIS IS A BIG ADJUSTMENT FROM THE PREVIOUS FORECAST...HAVE RAMPED UP RAIN CHANCES FRI INTO SAT...BUT THESE MAY BE UNDERDONE...ESPECIALLY FOR SAT WHERE THERE IS A TREND IN THE FORECAST TO DRY THINGS OUT SAT INTO SUN. LATEST ECMWF KEEPS CONDITIONS WET INTO SUN WITH A GUSTY NW FLOW ON THE BACKSIDE. SO THIS IS THE POINT IN THE FORECAST WHERE CONDITIONS MAY CONTINUE TO DETERIORATE WITH SUBSEQUENT MODEL RUNS. ONCE AGAIN...WHILE THE FORECAST HAS AGGRESSIVELY TAKEN A DOWNWARD NOTE FOR THE HOLIDAY WEEKEND...RAIN CHANCES MAY BE ON THE INCREASE SAT INTO SUN BASED ON LATEST TRENDS IN THE MODEL GUIDANCE. IN ADDITION...SOME OF THE RAINFALL ON FRI...OR AT LEAST THE FIRST HALF OF THE DAY MAY BE CONVECTIVE WITH LOCALIZED HEAVY RAINFALL WITH ANY EMBEDDED THUNDERSTORMS. THEREAFTER...THE AIRMASS STABILIZES IN THE LOW-LEVELS WITH POST-FRONTAL RAIN/SHOWERS...PRIMARILY DRIVEN BY FRONTOGENETIC FORCING ON THE BACKSIDE OF THE LOW. WIND GUSTS SAT INTO SUN MAY BE UP TO 35 MPH...BUT THIS IS THE POTENTIAL...WITH THE FORECASTS SIGNIFICANTLY LOWER AT THIS TIME. AS FOR TEMPS...DAYTIME HIGHS WITH THE CLOUD COVER AND RAIN WILL BE 5 TO 10 DEGREES BELOW NORMAL. STAYED BELOW GUIDANCE. OVERNIGHT LOWS WILL BE CLOSE TO SEASONABLE. A GRADUAL WARM-UP TO NEAR SEASONABLE LEVELS IS THEN FORECAST MON-WED. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON. AS A RESULT...IMPROVEMENT HAS BEEN QUITE SLOW. IFR/MVFR CIGS AND VSBY GENERALLY THE STANDARD. SOME POTENTIAL FOR A LITTLE MORE IMPROVEMENT PRIMARILY AT NW TERMINALS. IFR CONDITIONS MAY BE A LITTLE SLOWER TO RETURN AT KEWR...KTEB...AND KSWF OVERNIGHT. HOWEVER...STILL HIGH ENOUGH POTENTIAL THAT IFR CONDITIONS WERE INCLUDED IN THESE TAFS IN ADDITION TO ALL OTHER SITES OVERNIGHT. POTENTIAL EXISTS FOR COASTAL TERMINALS TO DROP TO LIFR AS WELL. LOW-END CHANCES FOR TS TO AFFECT ANY ONE TERMINAL SITE AFTER 18Z THURSDAY. HOWEVER...DID INCLUDE PROB30 GROUPS AT 30-HOUR SITES TO INDICATE THE GROWING POTENTIAL LATE IN THE DAY. 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: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING. KLGA FCSTER COMMENTS: POTENTIAL FOR CIGS TO GO VFR BRIEFLY EARLY THIS EVENING. KEWR FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. KTEB FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. KHPN FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST TONIGHT. KISP FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE....PRIMARILY THUR NIGHT AND FRIDAY. IFR POSSIBLE IN FOG AND STRATUS. .SATURDAY...SHRA LIKELY WITH MVFR OR LOWER. N WINDS 25-30G35KT. .SUNDAY...MOST LIKELY VFR WITH NW WINDS 20-25KT. POTENTIAL FOR G UP TO 40KT. .MONDAY...VFR. NW WINDS 15-20G25KT. && .MARINE... LATEST SATELLITE IMAGERY...WEB-CAMS...AND RAP SOUNDINGS WARRANT EXTENDING DENSE FOG ADVISORY FOR THE WATERS S/W OF LONG ISLAND THROUGH TONIGHT. MIGHT ULTIMATELY END UP NEED TO EXTEND INTO THURSDAY MORNING - BUT TO MUCH UNCERTAINTY WITH TIMING OF MIXING AHEAD OF APPROACHING SHORTWAVE LATE TONIGHT TO DO SO AT THIS TIME. SEAS ARE RUNNING 1-2 FT BELOW WAVEWATCH FORECAST - SO FOR NOW HAVE TAKEN 1 FT OFF OF WAVEWATCH THROUGH THURSDAY NIGHT. STILL EXPECT SEAS TO COME UP TO SCA LEVELS TONIGHT AND CONTINUE THROUGH THURSDAY NIGHT. WINDS ALSO INCREASE LATE TONIGHT AND REMAIN UP INTO THURSDAY NIGHT. INCREASING LOW LEVEL JET THROUGH THURSDAY NIGHT INCREASES POTENTIAL FOR SCA LEVEL GUSTS OVER THE COASTAL OCEAN WATERS - SO HAVE KEPT HEADLINE AS SCA VICE CONVERTING TO AN SCA FOR HAZARDOUS SEAS. MARINE INVERSION APPEARS WILL LIMIT MIXING - SO WHILE COULD SEE OCCASIONAL GUSTS TO 25 KT OVER THE REMAINDER OF THE WATERS FROM LATE TONIGHT INTO THURSDAY NIGHT - DO NOT HAVE CONFIDENCE TO ISSUE SCA AT THIS TIME FOR THE NON-OCEAN ZONES. THERE IS A GOOD POTENTIAL FOR SCA CONDITIONS TO CONTINUE THROUGH THE UPCOMING WEEKEND AS LOW PRESSURE FORMS OVER THE WATERS ON FRI AND LIFTS SLOWLY TO THE NORTH AND EAST. SCA CONDITIONS ARE BECOMING INCREASINGLY LIKELY...WITH THE POTENTIAL FOR GALE CONDITIONS SAT INTO SUN. WINDS AND SEAS BEGIN TO SUBSIDE LATE SUN INTO MON WITH HIGH PRESSURE BUILDING IN FROM THE GREAT LAKES REGION. && .HYDROLOGY... THERE IS THE POTENTIAL FOR AROUND 3/4 TO 1 INCH BASIN AVERAGE QPF THURSDAY AND THURSDAY NIGHT WITH LOCALLY HIGHER AMOUNTS. DO NOT EXPECT ANY WIDESPREAD FLOOD THREAT THURSDAY FROM ANY SHRA/TSRA BUT COULD SEE SOME MINOR FLOODING UNDER ANY STRONGER CONVECTION - ESPECIALLY IF THERE IS ANY TRAINING. THE HEAVIEST RAINFALL IN THIS TIME FRAME WILL BE LATE THURSDAY NIGHT - WITH LOCALIZED RAINFALL RATES OF 1-1.5 INCHES/HR POSSIBLE NOTING PRECIPITABLE WATERS OF 1.5-1/75 INCHES IN THIS TIME FRAME. IF THESE RATES ARE REALIZED...ESPECIALLY IF THE STORMS PRODUCING THEM PASS OVER AREAS RECEIVING LOCALLY HEAVY RAINFALL THURSDAY...THERE IS THE POTENTIAL FOR LOCALIZED FLASH FLOODING. THE THREAT FOR LOCALIZED HEAVY RAINFALL WILL CONTINUE INTO THE FIRST HALF OF FRI WITH EMBEDDED CONVECTION. THEREAFTER...A STRATIFORM RAIN AND/OR SHOWERS DEVELOPS ON THE BACKSIDE OF DEVELOPING LOW PRESSURE. AN ADDITIONAL 1 TO 2 INCHES OF RAINFALL IS POSSIBLE FRI INTO SAT. THIS MAY EXACERBATE ANY ONGOING FLOODING. RAIN MAY LINGER EVEN INTO SUN BASED ON LATEST MODEL TRENDS. 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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ338-345-350- 353-355. SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ350-353-355. && $$ SYNOPSIS...MALOIT/DW NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...DW AVIATION...PICCA/MET MARINE...MALOIT/DW HYDROLOGY...MALOIT/DW
AREA FORECAST DISCUSSION
NWS ALBANY NY
433 PM EDT WED MAY 22 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY APPROACH THE REGION INTO FRIDAY. PERIODS OF SHOWERS AND THUNDERSTORMS WILL PRECEDE THE FRONT. THE RAIN WILL BE HEAVY AT TIMES. COOLER AND SHOWERY CONDITIONS WILL PERSIST INTO THE FIRST HALF OF THE MEMORIAL DAY WEEKEND. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... ...SEVERE THUNDERSTORM WATCH 210 IN EFFECT UNTIL 10 PM... MAIN BAND OF CONVECTION AND ASSOCIATED SEVERE WEATHER AND FLOODING RAINFALL CONTINUES TO PROGRESS EAST. SOME REPORTS OF WIND DAMAGE IN SCHENECTADY AND SCHOHARIE COUNTIES. MEANWHILE...HEAVY RAINFALL...RADAR ESTIMATE SHOWS 2-3 INCHES HAS LED TO URBAN FLOODING IN SCHENECTADY COUNTY. WITH MCS-LIKE SYSTEM CONTINUING TO TRACK NORTHEAST THROUGH THE LATE AFTERNOON SEVERE THREAT/FLASH FLOOD THREAT WILL CONTINUE EAST. ATTENTION WILL TURN TO ACTIVITY FOR LATER THIS AFTERNOON AND TONIGHT. CURRENTLY TO OUR WEST LAKE BREEZES ARE FORCING ISOLD TSRA. HRRR SHOWS LAKE BREEZE TO BLOSSOM WITH CONVECTION INTO LATER THIS AFTERNOON AND EVENING AS LARGER SCALE ASCENT TRANSLATES EASTWARD FROM LOWER LAKES. INSTABILITY HAS RECOVERED ACROSS WESTERN CWA WITH MESOANALYSIS SHOWS CAPES IN 1500-2000 J/KG RANGE. BULK SHEAR WILL REMAIN FAVORABLE FOR SEVERE STORMS WITH VALUES INTO THE 30-40 KNOT RANGE. WILL CARRY ENHANCED WORDING TO COINCIDE WITH WATCH...THEN SCT SHRA/TSRA THROUGH REMAINDER OF OVERNIGHT AS WAIT TO SEE HOW CONVECTION EVOLVES. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... COLD FRONT SLOWLY APPROACHES THE REGION ON THURSDAY...NOT CLEARING CWA UNTIL FRIDAY MORNING. SLOWLY MOVING FRONT WILL PROVIDE ENVIRONMENT FOR BOUTS OF HEAVY RAIN THROUGH THE PERIOD. PWATS REMAIN IN THE 1.5 INCH RANGE THROUGH THURSDAY...ONLY SLOWLY DROPPING OFF INTO FRIDAY. APPROACHING UPPER LEVEL JET TOMORROW BRINGS RIGHT REAR QUAD INTO FORECAST AREA FOR THE AFTERNOON. SEE HYDRO SECTION FOR DISCUSSION ON FLOOD RISK. SEVERE POTENTIAL TOMORROW IS NOT CLEAR CUT NOW. MODEL CAPE LOOKS TO BE IN THE 1000 J/KG RANGE WITH BULK SHEAR RESPECTABLE IN THE 30-40 KNOT RANGE. MID LEVEL LAPSE RATES ARE RELATIVELY WEAK AT 5.5C/KM. SPC HAS REGION IN SEE TEXT. FROM TODAY/S VANTAGE POINT THAT LOOKS APPROPRIATE. WITH COLD FRONT MOVING THROUGH ON FRIDAY...SOME DIMINISHING IN PRECIP EXPECTED FOR PART OF FRIDAY. HOWEVER GFS AND ECMWF COMING INTO AGREEMENT ON CUT OFF MIGRATING SLOWLY FROM DELMARVA INTO NEW ENGLAND INTO THE HOLIDAY WEEKEND. THIS WILL KEEP THE THREAT OF RAIN/SHOWERS IN THE FORECAST FOR FRIDAY. WITH CWA ON COOL SIDE OF SURFACE LOW TRACK...INSTABILITY LOOKS NEAR NIL. SO NO MENTION OF TSRA FOR FRIDAY. MINS ON SATURDAY MORNING IN ADIRONDACKS ARE FORECAST IN MID 30S. THIS WOULD MEAN THREAT OF FROST GIVEN BEGINNING OF THE GROWING SEASON THERE. WILL DEPEND ON CLOUDS AND PRECIP. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... MODEL GUIDANCE HAS TRENDED TO A WET START TO THE HOLIDAY WEEKEND ALONG WITH CHILLY TEMPERATURES DUE TO MORE CLOUD COVER. THE MODEL GUIDANCE HAS COME INTO FAIRLY GOOD AGREEMENT THAT AN AREA OF LOW PRESSURE WILL FORM ON THE COLD FRONT JUST OFF COAST NEAR CAPE COD AS SHORT WAVES MOVE THROUGH THE LONGWAVE. AN UPPER LEVEL LOW IS EXPECTED TO DEVELOP OVER THE MID ATLANTIC REGION FRIDAY NIGHT WITH ADDITIONAL SHORT WAVES MAINTAINING THIS UPPER LOW WITH IT MOVING GRADUALLY NORTHWARD UP THE COAST. THE LOW ALONG THE BOUNDARY WILL SLOW THE FRONT`S EASTWARD PROGRESS AND THROW RAIN SHOWERS AND CLOUDS BACK ACROSS NEW ENGLAND AND EASTERN NEW YORK STATE SATURDAY. THE REGION WILL REMAIN UNDER CYCLONIC FLOW THROUGH THE WEEKEND WITH UPPER RIDGING NOT EXPECTED TO BEGIN TO BUILD IN UNTIL TUESDAY. AT THE SURFACE...HIGH PRESSURE SHOULD BEGIN TO BUILD IN MONDAY AND ESPECIALLY TUESDAY. IT APPEARS THE HIGH SHOULD HOLD ON FOR WEDNESDAY. AS FOR TEMPERATURES...CHILLY. TEMPERATURES ARE EXPECTED TO RUN 10 TO 15 DEGREES BELOW NORMAL SATURDAY AND AGAIN SUNDAY. BRISK AND GUSTY NORTHWESTERLY WINDS WILL ONLY ADD TO THE CHILL. TEMPERATURES ARE EXPECTED TO MODERATE TOWARD SEASONABLE LEVELS MONDAY WITH THE HELP OF SUNSHINE BUT STILL BE BELOW NORMAL BY AROUND 5 DEGREES. THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY... GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY. NIGHTTIME LOWS OVER THE WEEKEND ARE EXPECTED TO BE IN THE 40S WITH 30S ACROSS THE HIGHER TERRAIN. WITH THE EXPANSION OF THE GROWING SEASON BY THIS TIME FROST ADVISORIES MIGHT BE NEEDED. CONDITIONS WILL BE MORE FAVORABLE FOR FROST SUNDAY NIGHT/MONDAY MORNING AND MONDAY NIGHT/TUESDAY MORNING. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... VFR PREVAILING WITH PERIODS OF MVFR FOR THE BALANCE OF THE AFTERNOON. SCATTERED -SHRA AND TSRA WILL DIRECTLY AFFECT OR BE IN THE VICINITY OF THE AIRPORTS FROM THE START OF THE TAF PERIOD THROUGH AT LEAST 22Z. CLOUDS WILL BE HARD TO CLEAR OUT...PARTICULARLY THE HIGH-LEVEL CI/CS...WHICH SHOULD LIMIT INSTABILITY AND THE PROLIFERATION OF TS. HIGH DEWPOINTS OVERNIGHT WILL RESULT IN SOME HAZY FOG...MAINLY MVFR...WITH A PERIOD OF IFR FOG POSS AT KPSF WHERE WINDS THRU THE COLUMN WILL BE LIGHTER. WITH LITTLE CHANGE IN THE ENVIRONMENT EXPECTED INTO EARLY THURSDAY...MVFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE AIRPORTS INTO THE EARLY AFTERNOON HOURS...WITH MORE TS ACTIVITY IS LIKELY...THOUGH PERHAPS NOT UNTIL AFTER THE END OF THE TAF PERIOD. EXPECTING A PERIOD OF MARGINAL SHEAR DURING THE EARLY NIGHT EXCEPT AT KPSF...35 KNOTS SHOULD BE ABOUT IT. SURFACE WINDS WILL HOLD UP OVERNIGHT AT LESS THAN 10 KNOTS...PICKING UP TO SPEEDS ON THURSDAY AVERAGING SLIGHTLY HIGHER THAN TODAY. OUTLOOK... THU PM AND NGT...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY. FRI-FRI NGT...MAINLY VFR. CHC -SHRA/-TSRA...MAINLY IN THE AM. SAT-SUN...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS INTO SATURDAY. PERIODS OF RAIN...MODERATE TO HEAVY AT TIMES WILL CONTINUE INTO THE HOLIDAY WEEKEND. RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THURSDAY AFTERNOON. WINDS WILL GENERALLY BE SOUTH AT 5 TO 10 MPH. && .HYDROLOGY... ECMWF AND GFS VERY AGGRESSIVE IN BRINGING HEAVY RAINFALL INTO CWA INTO THE MEMORIAL DAY WEEKEND. OPERATIONAL ECMWF AND GFS PRODUCE 5-7.5 INCHES OF RAIN IN CWA INTO SUNDAY. GEFS SHOW AVERAGE OF 2.25 INCHES THROUGH WEEKEND WITH 4 MEMBERS PUSHING IN EXCESS OF 3 INCHES. WHILE NOT QUITE READY TO ACCEPT TOTALS OF EURO AND GFS...ENOUGH GUIDANCE AVAILABLE TO AT LEAST WARRANT POTENTIAL OF HEAVY RAIN THREAT IN HWO. FIRST CHALLENGE FOR HEAVY RAIN WILL COME TOMORROW WITH SLOWLY MOVING FRONT. EASTERN CWA AND CENTRAL CWA HAVE SEEN HEAVIEST RAIN OVER THE LAST TWO DAYS AND WOULD APPEAR TO BE THE REGION WHERE FLASH FLOOD THREAT IS AT HIGHEST. WILL MONITOR CLOSELY FOR AT LEAST POTENTIAL OF FLASH FLOOD OR FLOOD WATCH THURSDAY INTO WEEKEND. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...OKEEFE NEAR TERM...OKEEFE SHORT TERM...OKEEFE LONG TERM...IAA AVIATION...ELH/WASULA FIRE WEATHER...OKEEFE HYDROLOGY...OKEEFE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
407 PM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN MOVE INTO WESTERN PORTIONS OF THE TRI-STATE THURSDAY NIGHT. A WAVE OF LOW PRESSURE DEVELOPS ALONG THIS SLOW MOVING COLD FRONT FRIDAY...REMAINS JUST EAST OF THE REGION SATURDAY...AND THEN TRACKS NORTH ALONG THE NEW ENGLAND COAST ON SUNDAY. HIGH PRESSURE OVER THE GREAT LAKES BUILDS SOUTHEAST ACROSS THE AREA MONDAY INTO TUESDAY. A WARM FRONT WILL THEN APPROACH FROM THE SOUTHWEST BY MID WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... WEAK FRONTAL BOUNDARY REMAINS STALLED JUST TO THE W AND S OF THE AREA...WITH A MARINE AIRMASS REMAINING IN PLACE. THIS FRONT SHOULD NOT MOVE MUCH...IF AT ALL TONIGHT...SO WOULD EXPECT MOST IF NOT ALL PRECIPITATION TO GO N OF THE AREA. THIS IS CONSISTENT WITH THE HRRR AND RAP...WHICH HAVE HAD THE BEST HANDLE ON THIS FRONT AND THE WEATHER TODAY BY FAR...ALONG WITH THE NAM AND SREF. BASED ON THIS HAVE GONE BASICALLY DRY ACROSS THE S 2/3 OF THE CWA THIS EVENING...WITH SLIGHT CHANCE POPS FAR N TIER...THEN SLIGHT CHANCE POPS THROUGHOUT OVERNIGHT IN RESPONSE TO AN APPROACHING 700-500 HPA SHORTWAVE. WITH MARINE LAYER INTACT - WOULD EXPECT LOW CLOUD DECK TO RE- ESTABLISH ITSELF ACROSS THE AREA OVERNIGHT. COULD SEE PATCHY FOG AS WELL - POSSIBLY LOCALLY DENSE NEAR THE ATLANTIC COAST. FOR LOWS USED A BLEND OF 50 PERCENT MAV GUIDANCE WITH 25 PERCENT MET GUIDANCE AND 25 PERCENT NAM 2-METER TEMPERATURES. FORECASTING LOWS 10-15 DEGREES ABOVE NORMAL. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... MIXING ASSOCIATED WITH PASSING 700-500 HPA SHORTWAVE THURSDAY MORNING SHOULD ERODE THE MARINE INVERSION - BUT STILL WILL BE LEFT WITH QUITE A BIT OF MID TO HIGH CLOUDS WITH MOIST SW FLOW ALOFT. PRE-FRONTAL TROUGH MOVING INTO THE LOWER HUDSON VALLEY/NE NJ THURSDAY AFTERNOON SHOULD SERVE AS TRIGGER FOR SCT-NUMEROUS SHRA WITH EMBEDDED TSRA. LIKELY POPS MAINLY FROM NYC-INTERIOR SW CT ZONES ON W AND CHANCE POPS EAST OF THAT LINE. SOME SUGGESTION FROM NAM/GFS THAT EASTERN AREAS WILL REMAIN DRY THURSDAY...BUT FOR NOW TOO MUCH LOW-MID LEVEL MOISTURE AND INCREASING LOW LEVEL JET TO FORECAST THAT AT THIS TIME. WITH 30-35 KT BULK SHEAR...1000-1500 J/KG OF CAPE AND BULK RICHARDSON NUMBERS 15-30 HAVE THE POTENTIAL FOR ISOLATED SEVERE STORMS THURSDAY AFTERNOON ACROSS NE NJ/LOWER HUDSON VALLEY AND MAYBE NYC AND SW CT ZONES. MAIN THREAT IS GUSTY WINDS AND LARGE HAIL. ALSO NEED TO WATCH FOR LOW LEVEL HELICITY WITH S SFC FLOW AND SW FLOW AT 850 HPA. FOR HIGHS THURSDAY USED A BLEND OF MIXING DOWN FROM 975 HPA NEAR THE COAST AND 950 HPA INLAND...WITH NAM 2-METER TEMPERATURES AND A BLEND OF MAV AND MET GUIDANCE. FORECASTING VALUES AROUND NORMAL EAST TO A FEW DEGREES ABOVE NORMAL WEST. DEEP SW FLOW ALOFT...BECOMES DIFFLUENT AT 500 HPA AFTER MIDNIGHT. HAVE THE POTENTIAL FOR HEAVY RAINFALL AS A RESULT. REFER TO THE HYDROLOGY SECTION FOR DETAILS. SEVERE THREAT COULD LINGER INTO THE EVENING ACROSS WESTERN ZONES AS WELL. FOR LOWS THURSDAY NIGHT USED A BLEND OF MAV/MET GUIDANCE WITH VALUES FORECAST AROUND 10 DEGREES ABOVE NORMAL. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... MODELS HAVE TRENDED CONSIDERABLY SLOWER AND DEEPER WITH THE APPROACHING UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY. THERE IS VERY GOOD AGREEMENT WITH THE 12Z GFS AND ECMWF ON TAKING A CLOSED UPPER LOW FROM THE MID ATLANTIC STATES ON FRI NE TO OVER NEW ENGLAND ON SUN. THE NAM AND GGEM ARE TRENDING IN THAT DIRECTION...BUT ARE MORE PROGRESSIVE BEYOND 00Z SAT. PREFERENCE AT THIS TIME IS TO GO WITH THE SLOWER GFS/ECMWF SOLUTION BASED ON MODEL TRENDS AND THE RUN TO RUN CONTINUITY BEING EXHIBITED OVER THE LAST SEVERAL MODEL CYCLES. AS FOR SENSIBLE WEATHER...THIS RESULTS IN A WET...COOL WEEKEND WITH THE POTENTIAL FOR ANOTHER 1 TO 2 INCHES OF RAINFALL IN THE FRI-SAT TIME FRAME. SINCE THIS IS A BIG ADJUSTMENT FROM THE PREVIOUS FORECAST...HAVE RAMPED UP RAIN CHANCES FRI INTO SAT...BUT THESE MAY BE UNDERDONE...ESPECIALLY FOR SAT WHERE THERE IS A TREND IN THE FORECAST TO DRY THINGS OUT SAT INTO SUN. LATEST ECMWF KEEPS CONDITIONS WET INTO SUN WITH A GUSTY NW FLOW ON THE BACKSIDE. SO THIS IS THE POINT IN THE FORECAST WHERE CONDITIONS MAY CONTINUE TO DETERIORATE WITH SUBSEQUENT MODEL RUNS. ONCE AGAIN...WHILE THE FORECAST HAS AGGRESSIVELY TAKEN A DOWNWARD NOTE FOR THE HOLIDAY WEEKEND...RAIN CHANCES MAY BE ON THE INCREASE SAT INTO SUN BASED ON LATEST TRENDS IN THE MODEL GUIDANCE. IN ADDITION...SOME OF THE RAINFALL ON FRI...OR AT LEAST THE FIRST HALF OF THE DAY MAY BE CONVECTIVE WITH LOCALIZED HEAVY RAINFALL WITH ANY EMBEDDED THUNDERSTORMS. THEREAFTER...THE AIRMASS STABILIZES IN THE LOW-LEVELS WITH POST-FRONTAL RAIN/SHOWERS...PRIMARILY DRIVEN BY FRONTOGENETIC FORCING ON THE BACKSIDE OF THE LOW. WIND GUSTS SAT INTO SUN MAY BE UP TO 35 MPH...BUT THIS IS THE POTENTIAL...WITH THE FORECASTS SIGNIFICANTLY LOWER AT THIS TIME. AS FOR TEMPS...DAYTIME HIGHS WITH THE CLOUD COVER AND RAIN WILL BE 5 TO 10 DEGREES BELOW NORMAL. STAYED BELOW GUIDANCE. OVERNIGHT LOWS WILL BE CLOSE TO SEASONABLE. A GRADUAL WARM-UP TO NEAR SEASONABLE LEVELS IS THEN FORECAST MON-WED. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON. AS A RESULT...IMPROVEMENT HAS BEEN QUITE SLOW. IFR/MVFR CIGS AND VSBY GENERALLY THE STANDARD. SOME POTENTIAL FOR A LITTLE MORE IMPROVEMENT PRIMARILY AT NW TERMINALS. RECENT OBS SHOW WINDS FINALLY TURNING S AT KJFK/KEWR...WHICH MAY BE A SIGN OF BRIEFLY INCREASING VSBY/CIGS. HOWEVER...BASED ON CURRENT OBS AND DEVELOPING S WIND...GROWING POTENTIAL FOR IFR VSBY TO PUSH BACK INTO COASTAL TERMINALS OVER NEXT FEW HOURS. POTENTIAL FOR CONDITIONS TO DROP SOLIDLY INTO IFR AGAIN TONIGHT...HOWEVER MUCH UNCERTAINTY EXISTS OVER TIMING AND EXTENT. POTENTIAL ALSO EXISTS FOR LIFR/VLIFR ACROSS COASTAL TERMINALS. DID NOT SHOW TS IN TAFS ON THURSDAY JUST YET...AS UPPER-LEVEL FLOW INDICATES STORMS MAY BE SLOW TO APPROACH WESTERN TERMINALS AND COULD HOLD OFF UNTIL LATE IN THE DAY. HOWEVER...LOW END POTENTIAL EXISTS AT W TERMS GENERALLY 23/18Z THROUGH 24/00Z. 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: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING. KLGA FCSTER COMMENTS: POTENTIAL FOR CIGS TO GO VFR BRIEFLY THIS AFTERNOON AND EARLY THIS EVENING. WIND DIRECTION MAY STAY E/NE A COUPLE HOURS LONGER THAN INDICATED IN TAF. KEWR FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST TONIGHT. KTEB FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST TONIGHT. KHPN FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST TONIGHT. KISP FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE....PRIMARILY THUR NIGHT AND FRIDAY. IFR POSSIBLE IN FOG AND STRATUS. .SATURDAY...SHRA LIKELY WITH MVFR OR LOWER. N WINDS 25-30G35KT. .SUNDAY...MOST LIKELY VFR WITH NW WINDS 20-25KT. POTENTIAL FOR G UP TO 40KT. .MONDAY...VFR. NW WINDS 15-20G25KT. && .MARINE... LATEST SATELLITE IMAGERY...WEB-CAMS...AND RAP SOUNDINGS WARRANT EXTENDING DENSE FOG ADVISORY FOR THE WATERS S/W OF LONG ISLAND THROUGH TONIGHT. MIGHT ULTIMATELY END UP NEED TO EXTEND INTO THURSDAY MORNING - BUT TO MUCH UNCERTAINTY WITH TIMING OF MIXING AHEAD OF APPROACHING SHORTWAVE LATE TONIGHT TO DO SO AT THIS TIME. SEAS ARE RUNNING 1-2 FT BELOW WAVEWATCH FORECAST - SO FOR NOW HAVE TAKEN 1 FT OFF OF WAVEWATCH THROUGH THURSDAY NIGHT. STILL EXPECT SEAS TO COME UP TO SCA LEVELS TONIGHT AND CONTINUE THROUGH THURSDAY NIGHT. WINDS ALSO INCREASE LATE TONIGHT AND REMAIN UP INTO THURSDAY NIGHT. INCREASING LOW LEVEL JET THROUGH THURSDAY NIGHT INCREASES POTENTIAL FOR SCA LEVEL GUSTS OVER THE COASTAL OCEAN WATERS - SO HAVE KEPT HEADLINE AS SCA VICE CONVERTING TO AN SCA FOR HAZARDOUS SEAS. MARINE INVERSION APPEARS WILL LIMIT MIXING - SO WHILE COULD SEE OCCASIONAL GUSTS TO 25 KT OVER THE REMAINDER OF THE WATERS FROM LATE TONIGHT INTO THURSDAY NIGHT - DO NOT HAVE CONFIDENCE TO ISSUE SCA AT THIS TIME FOR THE NON-OCEAN ZONES. THERE IS A GOOD POTENTIAL FOR SCA CONDITIONS TO CONTINUE THROUGH THE UPCOMING WEEKEND AS LOW PRESSURE FORMS OVER THE WATERS ON FRI AND LIFTS SLOWLY TO THE NORTH AND EAST. SCA CONDITIONS ARE BECOMING INCREASINGLY LIKELY...WITH THE POTENTIAL FOR GALE CONDITIONS SAT INTO SUN. WINDS AND SEAS BEGIN TO SUBSIDE LATE SUN INTO MON WITH HIGH PRESSURE BUILDING IN FROM THE GREAT LAKES REGION. && .HYDROLOGY... THERE IS THE POTENTIAL FOR AROUND 3/4 TO 1 INCH BASIN AVERAGE QPF THURSDAY AND THURSDAY NIGHT WITH LOCALLY HIGHER AMOUNTS. DO NOT EXPECT ANY WIDESPREAD FLOOD THREAT THURSDAY FROM ANY SHRA/TSRA BUT COULD SEE SOME MINOR FLOODING UNDER ANY STRONGER CONVECTION - ESPECIALLY IF THERE IS ANY TRAINING. THE HEAVIEST RAINFALL IN THIS TIME FRAME WILL BE LATE THURSDAY NIGHT - WITH LOCALIZED RAINFALL RATES OF 1-1.5 INCHES/HR POSSIBLE NOTING PRECIPITABLE WATERS OF 1.5-1/75 INCHES IN THIS TIME FRAME. IF THESE RATES ARE REALIZED...ESPECIALLY IF THE STORMS PRODUCING THEM PASS OVER AREAS RECEIVING LOCALLY HEAVY RAINFALL THURSDAY...THERE IS THE POTENTIAL FOR LOCALIZED FLASH FLOODING. THE THREAT FOR LOCALIZED HEAVY RAINFALL WILL CONTINUE INTO THE FIRST HALF OF FRI WITH EMBEDDED CONVECTION. THEREAFTER...A STRATIFORM RAIN AND/OR SHOWERS DEVELOPS ON THE BACKSIDE OF DEVELOPING LOW PRESSURE. AN ADDITIONAL 1 TO 2 INCHES OF RAINFALL IS POSSIBLE FRI INTO SAT. THIS MAY EXACERBATE ANY ONGOING FLOODING. RAIN MAY LINGER EVEN INTO SUN BASED ON LATEST MODEL TRENDS. 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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ338-345-350- 353-355. SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR ANZ350-353-355. && $$ SYNOPSIS...MALOIT/DW NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...DW AVIATION...PICCA MARINE...MALOIT/DW HYDROLOGY...MALOIT/DW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
215 PM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN PASS THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... BACK DOOR COLD FRONT THAT WENT THROUGH OVERNIGHT REMAINS STALLED OUT TO THE W AND S OF THE AREA. HRRR AND RAP ARE THE ONLY MODELS WITH ANY CLUE TO ITS EXISTENCE. LOOKING AT TRENDS IN VISIBLE SATELLITE AND RAP SOUNDINGS...HAVE DOUBTS ABOUT HRRR/RAP SHOWING BOUNDARY PUSH BACK INTO FAR W ZONES AS A WARM FRONT LATE THIS AFTERNOON. AS A RESULT HAVE KEPT FORECAST CLOUDY-MOSTLY CLOUDY AND LOWERED TEMPERATURES AGAIN. NOW FORECASTING HIGHS MAINLY IN THE 70S...WITH UPPER 60S AT THE IMMEDIATE COAST. STILL APPEARS MOST OF THE AREA WILL BE DRY THIS AFTERNOON PER HRRR/RAP. HOWEVER WITH CONVECTION FIRING W OF AREA...HAVE KEPT SLIGHT CHANCE TO CHANCE POPS THIS AFTERNOON OVER THE NW 1/2 OF THE CWA WITH A SLIGHT CHANCE OF THUNDER. ANY THUNDERSTORMS WILL MOST LIKELY BE ELEVATED IN NATURE AS THEY MOVE OVER THE AREA DUE TO THE MARINE INVERSION IN PLACE...SO THE SEVERE THREAT THIS AFTERNOON IS NIL ACROSS THE SE 1/2 OF THE CWA AND LESS THAN 5 PERCENT ELSEWHERE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... INCREASING CONCERN THAT THE MARINE LAYER WILL NOT DISSIPATE/FRONT LIFT TO THE N BY THIS EVENING - AND THAT THE MARINE LAYER WILL MAINTAIN ITSELF OVER MOST IF NOT ALL THE AREA TONIGHT. WILL CONTINUE TO MONITOR TRENDS - BUT COULD END UP MAKING SIGNIFICANT CHANGES TO TONIGHTS FORECAST IF CURRENT TRENDS HOLD. SCT-ISOLD SHOWERS AND TSTMS THIS EVENING. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THURSDAY AS THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT APPROACH THE AREA. HIGHS ON THURSDAY IN THE MID TO UPPER 70S. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... MAIN ISSUE FOR THE START OF THIS PERIOD IS THE INTERACTION OF THE EASTWARD MOVING CENTRAL US TROUGH WITH SEVERAL NORTHERN STREAM SHORTWAVES ROTATING AROUND A PERSISTENT EASTERN CANADIAN TROUGH. THE COMPLEX INTERACTION IS RESULTING IN TIMING AND AMPLIFICATION ISSUES AS THIS TROUGH SLIDES TO THE EAST COAST. GFS CONTINUES TO BE SLOWER THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW NEGATIVELY TILTS AND CLOSES OFF AS IT APPROACHES THE MID ATLANTIC STATES. THIS WOULD RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. WITH MAJORITY OF 00Z OPERATIONAL GUIDANCE TRENDING A BIT SLOWER...HAVE ALSO TRENDED A BIT SLOWER WITH PRECIPITATION GRADUALLY TAPERING OFF FRI AFTERNOON INTO FRI NIGHT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER. AS FOR THE SENSIBLE WEATHER...COLD FRONT SLOWLY CROSSES THE REGION THU NIGHT INTO FRI. ALTHOUGH INSTABILITY WILL LIKELY BE FALLING TO MARGINAL LEVELS THURSDAY NIGHT...WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT IS LIKELY WITH ABUNDANT MOISTURE STREAMING AHEAD OF APPROACHING SHORTWAVE ENERGY/COLD FRONT. THE SEVERE THREAT SHOULD DIMINISH INTO THURSDAY NIGHT...WITH HEAVY RAIN THE MAIN THREAT WITH PWATS ABOUT 2 STD ABOVE NORMAL AND STEERING FLOW NEARLY ALIGNED WITH THE SLOW MOVING FRONT. WILL HAVE TO MONITOR THE EXTENT OF INTERACTION OF THE FRONT WITH A SUBTROPICAL PLUME STREAMING UP THE COAST THURSDAY NIGHT...WHICH IF CLOSER TO THE COAST WOULD ENHANCE THE FLASH FLOOD THREAT. CONVECTIVE THREAT SHOULD DECREASE IN THE WAKE OF THE COLD FRONT...BUT POTENTIAL WAVE DEVELOPMENT COULD PROLONG LIGHT TO MODERATE POST-FRONTAL STRATIFORM RAINS THROUGH FRIDAY INTO FRI NIGHT...PARTICULARLY ACROSS EASTERN SECTIONS. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. A DRYING NW FLOW SET UPS FRI NIGHT INTO SAT WITH STRONG COLD ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES BELOW SEASONABLE LEVELS. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS AFTERNOON. AS A RESULT...IMPROVEMENT HAS BEEN QUITE SLOW. IFR/MVFR CIGS AND VSBY GENERALLY THE STANDARD. SOME POTENTIAL FOR A LITTLE MORE IMPROVEMENT PRIMARILY AT NW TERMINALS. RECENT OBS SHOW WINDS FINALLY TURNING S AT KJFK/KEWR...WHICH MAY BE A SIGN OF BRIEFLY INCREASING VSBY/CIGS. HOWEVER...BASED ON CURRENT OBS AND DEVELOPING S WIND...GROWING POTENTIAL FOR IFR VSBY TO PUSH BACK INTO COASTAL TERMINALS OVER NEXT FEW HOURS. POTENTIAL FOR CONDITIONS TO DROP SOLIDLY INTO IFR AGAIN TONIGHT...HOWEVER MUCH UNCERTAINTY EXISTS OVER TIMING AND EXTENT. POTENTIAL ALSO EXISTS FOR LIFR/VLIFR ACROSS COASTAL TERMINALS. DID NOT SHOW TS IN TAFS ON THURSDAY JUST YET...AS UPPER-LEVEL FLOW INDICATES STORMS MAY BE SLOW TO APPROACH WESTERN TERMINALS AND COULD HOLD OFF UNTIL LATE IN THE DAY. HOWEVER...LOW END POTENTIAL EXISTS AT W TERMS GENERALLY 23/18Z THRU 24/00Z. 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: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING. KLGA FCSTER COMMENTS: POTENTIAL FOR CIGS TO GO VFR BRIEFLY THIS AFTERNOON AND EARLY THIS EVENING. WIND DIRECTION MAY STAY E/NE A COUPLE HOURS LONGER THAN INDICATED IN TAF. KEWR FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST TONIGHT. KTEB FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST TONIGHT. KHPN FCSTER COMMENTS: CIGS MAY RISE HIGHER THAN INDICATED IN TAF OVER NEXT 2-3 HOURS. POTENTIAL FOR VSBY/CIGS LOWER THAN FORECAST TONIGHT. KISP FCSTER COMMENTS: POSSIBILITY FOR VSBY TO DROP QUICKER/LOWER THAN FORECAST LATE THIS AFTERNOON INTO THIS EVENING. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE....PRIMARILY THUR NIGHT AND FRIDAY. IFR POSSIBLE IN FOG AND STRATUS. .SATURDAY...SHRA LIKELY WITH MVFR OR LOWER. N WINDS 25-30G35KT. .SUNDAY...MOST LIKELY VFR WITH NW WINDS 20-25KT. POTENTIAL FOR G UP TO 40KT. .MONDAY...VFR. NW WINDS 15-20G25KT. && .MARINE... BASED ON HRRR AND LATEST TRENDS IN OBSERVATIONS AND WEB-CAMS HAVE EXTENDED THE DENSE FOG ADVISORY FOR THE COASTAL OCEAN ZONES...NY HARBOR AND THE SOUTH SHORE BAYS OF LONG ISLAND THROUGH 22Z. GIVEN NO RESTRICTIONS OF 1NM OR LESS IN VISIBILITY EVIDENT ON SOUND OR EASTERN BAYS OF LONG ISLAND...HAVE CANCELLED THE DENSE FOG ADVISORY THERE. THERE SEEMS TO BE INCREASING POTENIAL FOR DENSE FOG OVER THE SOUTHERN WATERS TO CONTINUE TONIGHT. IF TRENDS HOLD...WILL EXTEND THE DENSE FOG ADVISORY IN TIME THROUGH TONIGHT WITH THE LATE AFTERNOON FORECAST ISSUANCE. SEAS ARE NOT INCREASING AS FAST AS FORECAST...SO HAVE ADJUSTED DOWNWARD A FOOT OR SO ACROSS MOST OCEAN AREAS INTO THIS EVENING. SEAS SLOWLY BUILD THIS AFTERNOON/EVENING TO SCA LEVELS ON THE COASTAL OCEAN WATERS AND REMAIN ABOVE SCA LEVELS THROUGH THURSDAY. SW FLOW INCREASES OVER THE COASTAL OCEAN WATERS TONIGHT AS WELL WITH SFC BOUNDARY LIFTING TO NEAR THE LONG ISLAND COAST IF NOT FARTHER N. A COLD FRONT WILL MOVE EAST ACROSS THE AREA WATERS LATE THURSDAY THROUGH FRIDAY AFTERNOON...WITH HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS SHOULD GRADUALLY FALL BELOW MARGINAL SCA LEVELS THURSDAY NIGHT...WITH SCA SEAS ON THE OCEAN LIKELY REMAINING ABOVE SCA CRITERIA THROUGH SATURDAY MORNING WITH RESIDUAL SOUTHERLY SWELLS. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS. && .HYDROLOGY... SCT SHOWERS/TSTMS THIS EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMOUNTS IN TSTMS. SHOWERS AND THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT LATE THU INTO FRIDAY MORNING...SHOULD PRODUCE AVERAGE BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD RESULT IN FLASH FLOODING. ADDITIONAL LIGHTER RAINFALL AMOUNTS ARE LIKELY FRIDAY...POSSIBLY INTO FRIDAY NIGHT. 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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ338-345- 350-353-355. SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT THURSDAY FOR ANZ350-353-355. && $$ SYNOPSIS...24/NV NEAR TERM...MALOIT/NV SHORT TERM...24 LONG TERM...NV AVIATION...PICCA MARINE...24/MALOIT/NV HYDROLOGY...24/NV
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1249 PM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN PASS THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... BACK DOOR COLD FRONT THAT WENT THROUGH OVERNIGHT REMAINS STALLED OUT TO THE W AND S OF THE AREA. HRRR AND RAP ARE THE ONLY MODELS WITH ANY CLUE TO ITS EXISTENCE. LOOKING AT TRENDS IN VISIBLE SATELLITE AND RAP SOUNDINGS...HAVE DOUBTS ABOUT HRRR/RAP SHOWING BOUNDARY PUSH BACK INTO FAR W ZONES AS A WARM FRONT LATE THIS AFTERNOON. AS A RESULT HAVE KEPT FORECAST CLOUDY-MOSTLY CLOUDY AND LOWERED TEMPERATURES AGAIN. NOW FORECASTING HIGHS MAINLY IN THE 70S...WITH UPPER 60S AT THE IMMEDIATE COAST. STILL APPEARS MOST OF THE AREA WILL BE DRY THIS AFTERNOON PER HRRR/RAP. HOWEVER WITH CONVECTION FIRING W OF AREA...HAVE KEPT SLIGHT CHANCE TO CHANCE POPS THIS AFTERNOON OVER THE NW 1/2 OF THE CWA WITH A SLIGHT CHANCE OF THUNDER. ANY THUNDERSTORMS WILL MOST LIKELY BE ELEVATED IN NATURE AS THEY MOVE OVER THE AREA DUE TO THE MARINE INVERSION IN PLACE...SO THE SEVERE THREAT THIS AFTERNOON IS NIL ACROSS THE SE 1/2 OF THE CWA AND LESS THAN 5 PERCENT ELSEWHERE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... INCREASING CONCERN THAT THE MARINE LAYER WILL NOT DISSIPATE/FRONT LIFT TO THE N BY THIS EVENING - AND THAT THE MARINE LAYER WILL MAINTAIN ITSELF OVER MOST IF NOT ALL THE AREA TONIGHT. WILL CONTINUE TO MONITOR TRENDS - BUT COULD END UP MAKING SIGNIFICANT CHANGES TO TONIGHTS FORECAST IF CURRENT TRENDS HOLD. SCT-ISOLD SHOWERS AND TSTMS THIS EVENING. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THURSDAY AS THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT APPROACH THE AREA. HIGHS ON THURSDAY IN THE MID TO UPPER 70S. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MAIN ISSUE FOR THE START OF THIS PERIOD IS THE INTERACTION OF THE EASTWARD MOVING CENTRAL US TROUGH WITH SEVERAL NORTHERN STREAM SHORTWAVES ROTATING AROUND A PERSISTENT EASTERN CANADIAN TROUGH. THE COMPLEX INTERACTION IS RESULTING IN TIMING AND AMPLIFICATION ISSUES AS THIS TROUGH SLIDES TO THE EAST COAST. GFS CONTINUES TO BE SLOWER THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW NEGATIVELY TILTS AND CLOSES OFF AS IT APPROACHES THE MID ATLANTIC STATES. THIS WOULD RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. WITH MAJORITY OF 00Z OPERATIONAL GUIDANCE TRENDING A BIT SLOWER...HAVE ALSO TRENDED A BIT SLOWER WITH PRECIPITATION GRADUALLY TAPERING OFF FRI AFTERNOON INTO FRI NIGHT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER. AS FOR THE SENSIBLE WEATHER...COLD FRONT SLOWLY CROSSES THE REGION THU NIGHT INTO FRI. ALTHOUGH INSTABILITY WILL LIKELY BE FALLING TO MARGINAL LEVELS THURSDAY NIGHT...WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT IS LIKELY WITH ABUNDANT MOISTURE STREAMING AHEAD OF APPROACHING SHORTWAVE ENERGY/COLD FRONT. THE SEVERE THREAT SHOULD DIMINISH INTO THURSDAY NIGHT...WITH HEAVY RAIN THE MAIN THREAT WITH PWATS ABOUT 2 STD ABOVE NORMAL AND STEERING FLOW NEARLY ALIGNED WITH THE SLOW MOVING FRONT. WILL HAVE TO MONITOR THE EXTENT OF INTERACTION OF THE FRONT WITH A SUBTROPICAL PLUME STREAMING UP THE COAST THURSDAY NIGHT...WHICH IF CLOSER TO THE COAST WOULD ENHANCE THE FLASH FLOOD THREAT. CONVECTIVE THREAT SHOULD DECREASE IN THE WAKE OF THE COLD FRONT...BUT POTENTIAL WAVE DEVELOPMENT COULD PROLONG LIGHT TO MODERATE POST-FRONTAL STRATIFORM RAINS THROUGH FRIDAY INTO FRI NIGHT...PARTICULARLY ACROSS EASTERN SECTIONS. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. A DRYING NW FLOW SET UPS FRI NIGHT INTO SAT WITH STRONG COLD ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES BELOW SEASONABLE LEVELS. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS MORNING. AS A RESULT...HAVE GONE MORE PESSIMISTIC WITH THE FORECAST THROUGH THE DAY...SHOWING IMPROVEMENT IN CIGS AND VSBY GENERALLY AROUND 17Z-21Z. HOWEVER CONFIDENCE IN THIS IMPROVEMENT...ESPECIALLY FOR CIGS...IS LOW. POTENTIAL FOR WINDS TO STAY LIGHTER / MORE EASTERLY FOR A LONGER PERIOD THAN INDICATED IN TAFS AS WELL. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON...GENERALLY AT KSWF AND PERHAPS KHPN. MARINE LAYER LIKELY TO KEEP TS AWAY FROM TERMINALS FARTHER SE. IT COULD BE ANOTHER TRICKY NIGHT FORECASTING VFR/IFR CONDITIONS. LATEST GUIDANCE IS HINTING AT IFR OR LESS CONDITIONS AT THE OUTLYING TERMINALS...HOWEVER GUIDANCE DIFFERS ON TIMING AND JUST HOW LOW CIGS AND VSBYS GET. WILL HOLD OFF IN LOWERING CONDITIONS TOO MUCH WITH LOW CONFIDENCE HOWEVER THIS WILL NEED TO BE MONITORED. HIGHEST CONFIDENCE OF IFR OR LOWER CONDITIONS WILL BE AT KGON. 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: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. KLGA FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. KEWR FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. KHPN FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AROUND 18-21Z...ESPECIALLY FOR CIGS. KISP FCSTER COMMENTS: LOW POTENTIAL FOR CIGS/VSBY TO IMPROVE TO MVFR OR HIGHER LEVELS AROUND 17-18Z. WIND SPEEDS MAY BE 1-2 HOURS SLOWER TO INCREASE THAN SHOWN IN TAF. .OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... .THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG AND STRATUS. .SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR WITH NW WINDS INCREASING TO 20-30KT. .SUNDAY...VFR WITH NW WINDS 20-25KT. && .MARINE... BASED ON HRRR AND LATEST TRENDS IN OBSERVATIONS AND WEB-CAMS HAVE EXTENDED THE DENSE FOG ADVISORY FOR THE COASTAL OCEAN ZONES...NY HARBOR AND THE SOUTH SHORE BAYS OF LONG ISLAND THROUGH 22Z. GIVEN NO RESTRICTIONS OF 1NM OR LESS IN VISIBILITY EVIDENT ON SOUND OR EASTERN BAYS OF LONG ISLAND...HAVE CANCELLED THE DENSE FOG ADVISORY THERE. THERE SEEMS TO BE INCREASING POTENIAL FOR DENSE FOG OVER THE SOUTHERN WATERS TO CONTINUE TONIGHT. IF TRENDS HOLD...WILL EXTEND THE DENSE FOG ADVISORY IN TIME THROUGH TONIGHT WITH THE LATE AFTERNOON FORECAST ISSUANCE. SEAS ARE NOT INCREASING AS FAST AS FORECAST...SO HAVE ADJUSTED DOWNWARD A FOOT OR SO ACROSS MOST OCEAN AREAS INTO THIS EVENING. SEAS SLOWLY BUILD THIS AFTERNOON/EVENING TO SCA LEVELS ON THE COASTAL OCEAN WATERS AND REMAIN ABOVE SCA LEVELS THROUGH THURSDAY. SW FLOW INCREASES OVER THE COASTAL OCEAN WATERS TONIGHT AS WELL WITH SFC BOUNDARY LIFTING TO NEAR THE LONG ISLAND COAST IF NOT FARTHER N. A COLD FRONT WILL MOVE EAST ACROSS THE AREA WATERS LATE THURSDAY THROUGH FRIDAY AFTERNOON...WITH HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS SHOULD GRADUALLY FALL BELOW MARGINAL SCA LEVELS THURSDAY NIGHT...WITH SCA SEAS ON THE OCEAN LIKELY REMAINING ABOVE SCA CRITERIA THROUGH SATURDAY MORNING WITH RESIDUAL SOUTHERLY SWELLS. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS. && .HYDROLOGY... SCT SHOWERS/TSTMS THIS EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMOUNTS IN TSTMS. SHOWERS AND THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT LATE THU INTO FRIDAY MORNING...SHOULD PRODUCE AVERAGE BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD RESULT IN FLASH FLOODING. ADDITIONAL LIGHTER RAINFALL AMOUNTS ARE LIKELY FRIDAY...POSSIBLY INTO FRIDAY NIGHT. 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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ338-345- 350-353-355. SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT THURSDAY FOR ANZ350-353-355. && $$ SYNOPSIS...MALOIT/24/NV NEAR TERM...MALOIT SHORT TERM...MALOIT/24 LONG TERM...NV AVIATION...BC/PICCA MARINE...MALOIT/24/NV HYDROLOGY...24/NV
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1104 AM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL REMAIN IN THE VICINITY INTO THURSDAY. A COLD FRONT WILL THEN SLOWLY APPROACH FROM THE WEST THURSDAY...THEN PASS THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HRRR IS THE ONLY MODEL WHICH SHOWS SHALLOW BACK DOOR FRONT MAKING PROGRESS AS FAR TO THE S AND W AS IT DID...AND HOLDS THE FRONT PRIMARILY TO OUT S AND W THROUGH MOST OF THE AFTERNOON. SUSPECT THAT EVEN THE HRRR IS TOO FAST TO ERODE MARINE LAYER. EXPECT MOST OF THE AREA TO BE CLOUDY THROUGH THE DAY AS A RESULT. FOR NOW HAVE SIGNIFICANTLY SCALED BACK ON POPS FOR TODAY...ESPECIALLY ACROSS THE SE 1/2 OF THE CWA...AND RESTRICTED PROBABILITY OF THUNDER TO SLIGHT CHANCE AND THEN ONLY OVER NW ZONES...AS STILL CANNOT RULE OUT CONVECTION FORMING OUTSIDE THE CWA THEN MOVING IN. TEMPERATURES LOWERED REFLECTING BLEND OF HRRR 2-METER TEMPERATURES AND LAV GUIDANCE - WHICH IS NOT ALL THAT BAD. DID NOT GO AS WARM AS THIS WOULD SUGGEST THOUGH OVER NW ZONES - GIVEN SUSPICION THAT MARINE LAYER HOLDS ON. WILL HAVE BETTER IDEA WHICH WAY TO PLAY NW/FAR W ZONES WITH NEXT UPDATE EARLY THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... HAVE CONCERN THAT IF THE MARINE LAYER DOES NOT DISSIPATE/FRONT LIFT TO THE N BY THIS EVENING - THAT THE MARINE LAYER WILL MAINTAIN ITSELF OVER MOST IF NOT ALL THE AREA TONIGHT. WILL CONTINUE TO MONITOR TRENDS - BUT COULD END UP MAKING SIGNIFICANT CHANGES TO TONIGHTS FORECAST IF CURRENT TRENDS HOLD. SCT-ISOLD SHOWERS AND TSTMS THIS EVENING. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THURSDAY AS THE UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT APPROACH THE AREA. HIGHS ON THURSDAY IN THE MID TO UPPER 70S. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MAIN ISSUE FOR THE START OF THIS PERIOD IS THE INTERACTION OF THE EASTWARD MOVING CENTRAL US TROUGH WITH SEVERAL NORTHERN STREAM SHORTWAVES ROTATING AROUND A PERSISTENT EASTERN CANADIAN TROUGH. THE COMPLEX INTERACTION IS RESULTING IN TIMING AND AMPLIFICATION ISSUES AS THIS TROUGH SLIDES TO THE EAST COAST. GFS CONTINUES TO BE SLOWER THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW NEGATIVELY TILTS AND CLOSES OFF AS IT APPROACHES THE MID ATLANTIC STATES. THIS WOULD RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. WITH MAJORITY OF 00Z OPERATIONAL GUIDANCE TRENDING A BIT SLOWER...HAVE ALSO TRENDED A BIT SLOWER WITH PRECIPITATION GRADUALLY TAPERING OFF FRI AFTERNOON INTO FRI NIGHT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER. AS FOR THE SENSIBLE WEATHER...COLD FRONT SLOWLY CROSSES THE REGION THU NIGHT INTO FRI. ALTHOUGH INSTABILITY WILL LIKELY BE FALLING TO MARGINAL LEVELS THURSDAY NIGHT...WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT IS LIKELY WITH ABUNDANT MOISTURE STREAMING AHEAD OF APPROACHING SHORTWAVE ENERGY/COLD FRONT. THE SEVERE THREAT SHOULD DIMINISH INTO THURSDAY NIGHT...WITH HEAVY RAIN THE MAIN THREAT WITH PWATS ABOUT 2 STD ABOVE NORMAL AND STEERING FLOW NEARLY ALIGNED WITH THE SLOW MOVING FRONT. WILL HAVE TO MONITOR THE EXTENT OF INTERACTION OF THE FRONT WITH A SUBTROPICAL PLUME STREAMING UP THE COAST THURSDAY NIGHT...WHICH IF CLOSER TO THE COAST WOULD ENHANCE THE FLASH FLOOD THREAT. CONVECTIVE THREAT SHOULD DECREASE IN THE WAKE OF THE COLD FRONT...BUT POTENTIAL WAVE DEVELOPMENT COULD PROLONG LIGHT TO MODERATE POST-FRONTAL STRATIFORM RAINS THROUGH FRIDAY INTO FRI NIGHT...PARTICULARLY ACROSS EASTERN SECTIONS. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. A DRYING NW FLOW SET UPS FRI NIGHT INTO SAT WITH STRONG COLD ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES BELOW SEASONABLE LEVELS. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... FRONTAL BOUNDARY CONTINUES TO LINGER OVER THE AREA THIS MORNING. AS A RESULT...HAVE GONE MORE PESSIMISTIC WITH THE FORECAST THROUGH THE DAY...SHOWING IMPROVEMENT IN CIGS AND VSBY GENERALLY AROUND 17Z-21Z. HOWEVER CONFIDENCE IN THIS IMPROVEMENT...ESPECIALLY FOR CIGS...IS LOW. POTENTIAL FOR WINDS TO STAY LIGHTER / MORE EASTERLY FOR A LONGER PERIOD THAN INDICATED IN TAFS AS WELL. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON...GENERALLY AT KSWF AND PERHAPS KHPN. MARINE LAYER LIKELY TO KEEP TS AWAY FROM TERMINALS FARTHER SE. IT COULD BE ANOTHER TRICKY NIGHT FORECASTING VFR/IFR CONDITIONS. LATEST GUIDANCE IS HINTING AT IFR OR LESS CONDITIONS AT THE OUTLYING TERMINALS...HOWEVER GUIDANCE DIFFERS ON TIMING AND JUST HOW LOW CIGS AND VSBYS GET. WILL HOLD OFF IN LOWERING CONDITIONS TOO MUCH WITH LOW CONFIDENCE HOWEVER THIS WILL NEED TO BE MONITORED. HIGHEST CONFIDENCE OF IFR OR LOWER CONDITIONS WILL BE AT KGON. 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: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. KLGA FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. KEWR FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER/MORE E FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AT 17Z...ESPECIALLY FOR CIGS. WINDS COULD STAY LIGHTER FOR 1-2 HOURS LONGER THAN INDICATED IN TAF. KHPN FCSTER COMMENTS: LOW CONFIDENCE IN MUCH IMPROVEMENT AROUND 18-21Z...ESPECIALLY FOR CIGS. KISP FCSTER COMMENTS: LOW POTENTIAL FOR CIGS/VSBY TO IMPROVE TO MVFR OR HIGHER LEVELS AROUND 17-18Z. WIND SPEEDS MAY BE 1-2 HOURS SLOWER TO INCREASE THAN SHOWN IN TAF. .OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... .THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG AND STRATUS. .SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR WITH NW WINDS INCREASING TO 20-30KT. .SUNDAY...VFR WITH NW WINDS 20-25KT. && .MARINE... BASED ON HRRR AND LATEST TRENDS IN OBSERVATIONS AND WEB-CAMS HAVE EXTENDED THE DENSE FOG ADVISORY FOR THE COASTAL OCEAN ZONES...NY HARBOR AND THE SOUTH SHORE BAYS OF LONG ISLAND THROUGH 22Z. GIVEN NO RESTRICTIONS OF 1NM OR LESS IN VISIBILITY EVIDENT ON SOUND OR EASTERN BAYS OF LONG ISLAND...HAVE CANCELLED THE DENSE FOG ADVISORY THERE. SEAS ARE NOT INCREASING AS FAST AS FORECAST...SO HAVE ADJUSTED DOWNWARD A FOOT OR SO ACROSS MOST OCEAN AREAS INTO THIS EVENING. SEAS SLOWLY BUILD THIS AFTERNOON/EVENING N TO SCA LEVELS AND REMAIN ABOVE SCA LEVELS THROUGH THURSDAY. SW FLOW INCREASES OVER THE COASTAL OCEAN WATERS TONIGHT AS WELL WITH SFC BOUNDARY LIFTING TO NEAR THE LONG ISLAND COAST IF NOT FARTHER N. A COLD FRONT WILL MOVE EAST ACROSS THE AREA WATERS LATE THURSDAY THROUGH FRIDAY AFTERNOON...WITH HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS SHOULD GRADUALLY FALL BELOW MARGINAL SCA LEVELS THURSDAY NIGHT...WITH SCA SEAS ON THE OCEAN LIKELY REMAINING ABOVE SCA CRITERIA THROUGH SATURDAY MORNING WITH RESIDUAL SOUTHERLY SWELLS. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS. && .HYDROLOGY... SCT SHOWERS/TSTMS THIS EVENING WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMOUNTS IN TSTMS. SHOWERS AND THUNDERSTORMS AHEAD OF AN APPROACHING COLD FRONT LATE THU INTO FRIDAY MORNING...SHOULD PRODUCE AVERAGE BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD RESULT IN FLASH FLOODING. ADDITIONAL LIGHTER RAINFALL AMOUNTS ARE LIKELY FRIDAY...POSSIBLY INTO FRIDAY NIGHT. 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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ338-345- 350-353-355. SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EDT THURSDAY FOR ANZ350-353-355. && $$ SYNOPSIS...24/NV NEAR TERM...24/MALOIT/NV SHORT TERM...24 LONG TERM...NV AVIATION...BC/PICCA MARINE...24/MALOIT/NV HYDROLOGY...24/NV
AREA FORECAST DISCUSSION
NWS ALBANY NY
1047 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE SAINT LAWRENCE VALLEY TOMORROW. WARM AND HUMID CONDITIONS WILL PERSIST INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. A STRONG COLD FRONT WILL MOVE SLOWLY THROUGH NEW YORK AND NEW ENGLAND INTO THURSDAY NIGHT. LOW PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH COLDER AIR POURS INTO THE REGION...AS THE WEATHER MAY STAY UNSETTLED INTO THE FIRST HALF OF THE MEMORIAL DAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM EDT... A STATIONARY FRONT REMAINS OVER ERN NY AND WRN NEW ENGLAND...AS IT APPEARS IT WILL BEGIN TO LIFT TO THE N/NE INTO THE EARLY PM...AS A SHORT-WAVE WITH SOME SCT SHOWERS AND ISOLD THUNDERSTORMS IS APPROACHING FROM WRN-CNTRL NY. THE POPS ARE GRADUALLY INCREASED IN THE LATE MORNING INTO THE EARLY PM. STRATUS IS HANGING TOUGH THIS MORNING...AND SHOULD GRADUALLY ERODE FROM SW TO NE. THE IS A BETTER AREA OF CLEARING OVER THE OH VALLEY. THERE IS YET...ANOTHER SHORT-WAVE MOVING TOWARD WRN PA. THIS DISTURBANCE MAY INCREASE THE POTENTIAL FOR SEVERE WX IN THE LATE PM/EARLY EVENING...ESPECIALLY OVER WRN NY WE HAVE BACK OFF THE SVR WX WORDING UNTIL AFTER 3 PM IN THE HOURLY GRIDS. THE SVR POTENTIAL WILL HINGE ON MORE SHEAR...AND LESSER AMOUNTS OF INSTABILITY. THE LATEST EXPERIMENTAL HRRR FROM THE SPC MESOANALYSIS PAGE SHOWS 40-50 KTS OF BULK SHEAR IN THE 0-6 KM LAYER FROM THE CAPITAL REGION NORTH...AND AND 30-40 KTS TO THE SOUTHEAST. INSTABILITY VALUES OFF THE 12Z NAM ARE GENERALLY 1000-1500 J/KG WITH SLIGHTLY HIGHER POCKETS OF SBCAPE. MID LEVEL LAPSE RATES ARE IN THE 6-6.5 C/KM RANGE. A NEW RUNNING OF THE LOCAL MAGLENTA SEVERE WEATHER INDEX SHOWS A MINOR SEVERE EVENT WITH THE FOLLOWING VALUES PLUGGED IN: CAPE=1000 K/KG MAX SOUNDING WINDS=50 KTS EHI=1.0 STORM SPEED= 35 KTS 0-3 KM SRH = 100 (M/S)^2 IF THE CAPE IS INCREASED TO 1500 J/KG...WE SHOW A MAJOR EVENT. THE CONVECTIVE MODE WOULD INDICATE SOME MULTICELLS AND OR ISOLD SUPERCELLS...POTENTIALLY CONGEALING INTO CLUSTERS AND LINES. THE SATELLITE TRENDS WILL BE MONITORED CAREFULLY. OUR LOCAL WRF SHOWS A FEW CLUSTERS DEVELOPING IN THE 0-3 KM COLUMNAR REF PRODUCT IN THE EARLY TO MID PM...AND CONTINUING OVERNIGHT. THE EXPERIMENTAL HRRR INDICATES LATE PM/EARLY PM.W PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL WITH VALUES OF 1.25-1.75 INCH RANGE...SO SOME HEAVY DOWNPOURS ARE POSSIBLE. OVERALL..THE SLIGHT RISK FOR OUR AREA LOOKS FINE...AND WE WILL CONTINUE TO MONITOR THE NEAR TERM TRENDS. MAX TEMPS IN THE M70S TO M80S LOOK FINE FOR NOW. CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE 60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY. REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT. BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS. HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT. BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF LINGERING SKIES MAY ONLY BE PS SAT IN GFS. TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS A FEW DEG...OR HOLDING STEADY. THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT. THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND WITH PERIODS OF RAW CHILLY RAIN. THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A FALL LIKE MEMORIAL DAY WEEKEND. WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT. && .LONG TERM /SUNDAY THROUGH TUESDAY/... THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER. GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20 MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD. ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM GRT PLAINS TO GRTLKS. PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND ABV BY TUESDAY AND WED. WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID. THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY... GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... SOME LOW CLOUDS ARE AFFECTING MOST OF THE TAF SITE THIS MORNING...WITH IFR SCATTERED VARIABLE BROKEN AT KALB...SOLID IFR AT KPSF AND KGFL AND SOLID MVFR AT KPOU. SOME FOG IS OCCURRING AT KPSF. THE LOW CLOUDS AND FOG SHOULD LIFT BTWN 13-15Z...LEAVING A MIX OF CLOUDS ABOVE 3000 FEET AGL FOR THE REST OF THE DAY AT ALL SITES. THUNDERSTORMS SHOULD DEVELOP AGAIN THIS AFTERNOON AND CONTINUE MUCH OF TONIGHT...BUT DUE TO THE SCATTERED NATURE...JUST PUTTING VCSH UNTIL REGIONS OF THUNDERSTORM DEVELOPMENT CAN BE OBSERVED AND MOVEMENT CAN BE TRACKED LATER TODAY. WHEREVER THUNDERSTORMS OCCUR...MVFR AND IFR CONDITIONS WILL OCCUR BUT AGAIN...SCATTERED NATURE TO THUNDERSTORMS PREVENTING ACKNOWLEDGING IN TAFS FOR NOW. WINDS SHOULD BE SOUTH TO SOUTHWEST AT 10 KT OR LESS TODAY... DIMINISHING TO LESS THAN 10 KT TONIGHT. OUTLOOK... THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY. THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG. FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM. SAT-SUN...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL CONTINUE INTO FRIDAY. RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON. WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING SOUTHWEST AROUND 10MPH THURSDAY. && .HYDROLOGY... PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN BANK RISES ARE LIKELY IN LARGER RIVERS. 3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY. DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS... BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS WILL THIS AFTERNOON INTO THURSDAY NIGHT. 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...SNYDER/WASULA NEAR TERM...SNYDER/WASULA SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...NAS/WASULA FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
800 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... TSTMS HAVE ENDED AND ONLY SCT -SHRA REMAIN MAINLY OVER S VT AND BERKSHIRE COUNTY. SOME ISOLD -SHRA ARE ALONG THE S TIER. FOR THE NEXT SVRL HOURS MOST OF THIS ACTIVITY WILL DIMINISH AND END. CLOUDS OVER MUCH OF FCA WILL THIN WITH INCRG SUNSHINE FOR A FEW HRS. THE HOOSIC RIVER AND SOME SMALL STREAMS IN SOUTHERN VERMONT HAVE REACHED BANK FULL AND MAY BRIEFLY EXCEED FLOOD THIS MORNING BEFORE RECEDING. WARNINGS AND ADVISORIES HAVE BEEN ISSUED TO COVER THESE SITUATIONS. AT SFC WMFNT IS N OF FCA. IT WILL MOVE TO ST LAWRENCE VLY TO MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL LLVL MOISTURE/CLOUDS FM TUES CONVECTION WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF 1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY. NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN. GOING TO HRRR FOR THE LATE AFTN: POU/ALB/GFL CAPE 2000/1812/1777 J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2 STORM SPEED 24/18/18 SRH 175/156/106 MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN CAPE AROUND 1000-1200 J/KG. PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL WITH VALUES OF 1.50-1.8 INCHES. SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED TIME OF LATER IN THE AFTN AND EVENING. CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE 60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY. REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT. BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS. HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT. BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF LINGERING SKIES MAY ONLY BE PS SAT IN GFS. TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS A FEW DEG...OR HOLDING STEADY. THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT. THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND WITH PERIODS OF RAW CHILLY RAIN. THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A FALL LIKE MEMORIAL DAY WEEKEND. WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT. && .LONG TERM /SUNDAY THROUGH TUESDAY/... THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER. GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20 MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD. ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM GRT PLAINS TO GRTLKS. PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND ABV BY TUESDAY AND WED. WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID. THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY... GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... SOME LOW CLOUDS ARE AFFECTING MOST OF THE TAF SITE THIS MORNING...WITH IFR SCATTERED VARIABLE BROKEN AT KALB...SOLID IFR AT KPSF AND KGFL AND SOLID MVFR AT KPOU. SOME FOG IS OCCURRING AT KPSF. THE LOW CLOUDS AND FOG SHOULD LIFT BTWN 13-15Z...LEAVING A MIX OF CLOUDS ABOVE 3000 FEET AGL FOR THE REST OF THE DAY AT ALL SITES. THUNDERSTORMS SHOULD DEVELOP AGAIN THIS AFTERNOON AND CONTINUE MUCH OF TONIGHT...BUT DUE TO THE SCATTERED NATURE...JUST PUTTING VCSH UNTIL REGIONS OF THUNDERSTORM DEVELOPMENT CAN BE OBSERVED AND MOVEMENT CAN BE TRACKED LATER TODAY. WHEREVER THUNDERSTORMS OCCUR...MVFR AND IFR CONDITIONS WILL OCCUR BUT AGAIN...SCATTERED NATURE TO THUNDERSTORMS PREVENTING ACKNOWLEDGING IN TAFS FOR NOW. WINDS SHOULD BE SOUTH TO SOUTHWEST AT 10 KT OR LESS TODAY... DIMINISHING TO LESS THAN 10 KT TONIGHT. OUTLOOK... THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY. THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG. FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM. SAT-SUN...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL CONTINUE INTO FRIDAY. RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON. WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING SOUTHWEST AROUND 10MPH THURSDAY. && .HYDROLOGY... PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN BANK RISES ARE LIKELY IN LARGER RIVERS. 3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY. DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS... BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS WILL THIS AFTERNOON INTO THURSDAY NIGHT. 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...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...NAS/WASULA FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
729 AM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL MOVE BACK NORTH AS A WARM FRONT TODAY. WARM AND HUMID CONDITIONS CONTINUE INTO THURSDAY AND FRIDAY WITH SHOWERS AND SCATTERED STRONG THUNDERSTORMS POSSIBLE. COOLER AND LESS HUMID CONDITIONS ARE EXPECTED FOR THIS HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE NORTHEAST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 730 AM UPDATE... CONVECTION IS FINALLY DYING DOWN AS IT ENTERS INTO ALREADY WORKED OVER AIR. EXPECT PRECIP TO CONTINUE TO MOVE EASTWARD AND DISSIPATE. TEMPS ARE SLOW TO REBOUND THIS MORNING...BUT WITH WINDS SOUTH OF THE PIKE ALREADY SWITCHING TO THE SW...EXPECT TEMPS TO JUMP LATER THIS MORNING. OTHERWISE BULK OF THE FORECAST REMAINS ON TRACK AS STRONG TO SEVERE WEATHER IS STILL ANTICIPATED ACROSS THE WESTERN HALF OF THE REGION. PREVIOUS DISCUSSION... CONTINUING TO MONITOR WAVES OF CONVECTION THIS MORNING. LATEST RUNS OF THE HRRR APPEAR TO HAVE THE BEST HANDLE ON THESE BANDS OF CONVECTION...ALTHOUGH ITS TIMING WAS SLOW BY A FEW HOURS. LEANED HEAVILY ON THE 05Z HRRR WITH THE APPROPRIATE TIMING ADJUSTMENT FOR THE EARLY MORNING FORECAST. SHOWERS AND THUNDERSTORMS ARE REASONABLY HOLDING TOGETHER IN A HIGH SHEAR/LOW CAPE ENVIRONMENT. LATER TODAY...EXPECTING THE STALLED BACK-DOOR COLD FRONT TO MOVE BACK NORTH AS A WARM FRONT. THERE ARE STILL SOME QUESTIONS AS TO HOW FAST THIS WILL HAPPEN. CURRENTLY THINKING THERE IS NOT ENOUGH PUSH TO DRIVE IT COMPLETELY THROUGH SOUTHERN NEW ENGLAND. AS SUCH...MAINTAINED COASTAL SEABREEZE FRONTS ALONG BOTH COASTS. THIS HAS BIG RAMIFICATIONS FOR TEMPERATURES ALONG THE EAST COAST. SHOULD THIS FRONT GET ENOUGH PUSH...CURRENT FORECAST TEMPERATURES ARE LIKELY 5-10 DEGREES TOO LOW ALONG THE IMMEDIATE COASTLINE. AM MORE CONFIDENT WITH TEMPERATURES FARTHER INLAND. SHOULD THERE BE MORE SUNSHINE THAT CURRENTLY THINKING...LIKELY TOO LOW FARTHER INLAND AS WELL. THINKING THERE WILL BE MORE CLOUDS THAN SUNSHINE TODAY OWING TO LOTS OF CONVECTIVE DEBRIS FROM THE OVERNIGHT SHOWERS...AS WELL AS NEW CONVECTIVE CLOUDS AS WE HEAD INTO THIS AFTERNOON. MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED LATER TODAY. THERE IS THE POSSIBILITY FOR MORE ISOLATED SEVERE WEATHER. THE GREATEST RISK SHOULD BE FARTHER WEST OF OUR REGION WHERE THE MORE FAVORABLE COMBINATION OF INSTABILITY AND SHEAR SHOULD BE. THE BEST ADVICE IS TO KEEP AN EYE ON THE SKY AND LATER FORECASTS IF YOU WILL BE OUTDOORS THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... TONIGHT...MORE OF THE SAME TONIGHT. WARM FRONT CONTINUES TO PUSH NORTH AS STRONGER SOUTH TO SOUTHWEST SYNOPTIC FLOW DEVELOPS. DECENT INSTABILITY PERSISTS THROUGH THE NIGHT. SO THINKING WE WILL BE SEEING ANOTHER NIGHT OF ISOLATED TO SCATTERED THUNDERSTORMS. THE GREATEST RISK OF THESE WILL BE ACROSS THE INTERIOR...AWAY FROM THE STABILIZING INFLUENCE OF THE OCEAN. THURSDAY...SOUTHERN NEW ENGLAND REMAINS IN THE WARM SECTOR OF A LOW PRESSURE MOVING FROM THE GREAT LAKES INTO THE SAINT LAWRENCE RIVER VALLEY. THIS LOW HAS A RATHER AMPLIFIED UPPER SYSTEM...SO ITS COLD FRONT WILL BE SLOW TO MOVE ACROSS OUR REGION. EXPECTING MORE ROUNDS OF SHOWERS AND SCATTERED THUNDERSTORMS. VERY HUMID AIRMASS IN PLACE AS WELL...WITH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES. WILL LIKELY SEE SOME HEAVY DOWNPOURS WITH SOME SHOWERS...ALONG WITH SOME HAIL AND GUSTY WINDS. MAY NOT QUITE REACH SEVERE THRESHOLDS AS CLOUDS WILL BE MORE PREVALENT... THUS TEMPERATURES SHOULD BE LOWER THAN WEDNESDAY. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * SCATTERED SHOWERS AND THUNDERSTORMS FRIDAY * COOLER AND LESS HUMID FOR THE WEEKEND CONFIDENCE LEVEL/MODEL GUIDANCE...MODERATE CONFIDENCE IN OVERALL FORECAST. 00Z MODELS CONTINUE TO SLOW DOWN THE ELONGATED TROUGH MOVING ACROSS THE EASTERN HALF OF THE CONUS. THERE IS STILL SOME TIMING DIFFERENCES ON WHEN THE SYSTEM WILL PUSH THROUGH THE NORTHEAST. REGARDLESS APPEARS THAT ELONGATED TROUGH WILL MOVE INTO NEW ENGLAND EVENTUALLY BECOMING A CUTOFF LOW BY THE WEEKEND. THIS LOW WILL EVENTUALLY MOVE INTO THE MARITIMES BY THE BEGINNING OF THE WORK WEEK AS HIGH PRESSURE MOVES IN. HAVE HIGH CONFIDENCE THAT PRECIP WILL OCCUR ON FRIDAY AND COOLER TEMPS WILL DOMINATE THE REGION FOR THE WEEKEND. LOW CONFIDENCE IN FORECAST AFTER TUES. DETAILS... THURSDAY NIGHT INTO FRIDAY... UPPER LEVEL TROUGH WILL PUSH THROUGH THE EASTERN GREAT LAKES REGION EVENTUALLY PUSHING A COLD FRONT THROUGH SOUTHERN NEW ENGLAND. MODELS CONTINUE TO SLOW THE TIMING OF THE FRONT DOWN...SO BELIEVE THAT IT MOVE THROUGH SOMETIME ON FRIDAY. BECAUSE OF THE MODEL DIFFERENCE HAVE LOW CONFIDENCE IN TIMING. REGARDLESS...BELIEVE THAT SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH WITH TEMPS NEAR AVG. CANNOT RULE OUT A FEW STRONG THUNDERSTORMS ESPECIALLY ACROSS REGIONS SOUTH OF THE I-84 CORRIDOR. MODELS INDICATE SOME INSTABILITY WITH ABOUT 25KTS OF SHEAR. PWAT VALUES OF OVER 1.5 INCHES LEADS FORECASTER TO BELIEVE THAT HEAVY DOWNPOURS IS THE MAIN THREAT...BUT WITH FALLING HEIGHTS AS COLD FRONT APPROACHES...SMALL HAIL AND GUSTY WINDS IS NOT OUT OF THE QUESTION. ANY CHANCE FOR STRONG STORMS TO DEVELOP WILL DIMINISH AFTER SUNSET AS DIURNAL HEATING IS LOST. WEEKEND...TRICKY FORECAST IS PLAYING OUT FOR THE WEEKEND. MODELS HAVE INDICATED THAT THE ELONGATED TROUGH WILL CUT OFF OVER THE MID ATLANTIC AND SLOWLY ROTATE OVER NEW ENGLAND FOR THE WEEKEND. THIS WILL ALLOW FOR MUCH COOLER AIR...WELL BELOW AVG AND EVEN HAS SLOWED DOWN THE TIMING OF PRECIP. BELIEVE THAT PRECIP MAY LINGER INTO SAT...BUT HAVE LOW CONFIDENCE THAT PRECIP WILL OCCUR ON SUNDAY. FOR NOW HAVE CONTINUED WITH THE SLOW DOWN TREND IN THE FORECAST. EXPECT HIGHS REACHING INTO THE MID TO UPPER 60S WITH LOWS DROPPING INTO THE MID TO UPPER 30S. IF SKIES CLEAR OUT AS THIS COLD POOL SITS OVER US...THERE IS A POSSIBILITY THAT FROST/FREEZE HEADLINES MAY BE NEEDED AS THE ENTIRE REGION IS OFFICIALLY IN THE GROWING SEASON. MONDAY AND BEYOND...SURFACE HIGH PRESSURE WILL BE IN CONTROL FOR THE FIRST HALF OF NEXT WEEK. THIS WILL HELP TEMPS REACH SEASONAL CONDITIONS. APPEARS THAT THERE IS LIMITED MOISTURE KEEPING THE FORECAST DRY...HOWEVER CANNOT RULE OUT A SPOT SHOWER OR TWO...ESP IF SEA BREEZES DEVELOPS. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW...MODERATE CONFIDENCE IN TIMING AND AREAL COVERAGE OF STRATUS AND FOG THROUGH THIS MORNING. TODAY...EXPECT MVFR-LIFR CONDITIONS TO GRADUALLY IMPROVE TO VFR 14-16Z AS SW WINDS DEVELOP. IFR MAY PERSIST MOST OF THE DAY AT KACK. ISOLATED TO SCATTERED CONVECTION BECOMING MORE WIDESPREAD THIS AFTERNOON...ESPECIALLY WEST OF KMHT-KORH-KIJD. TONIGHT...MODERATE CONFIDENCE IN TRENDS. EXPECT VARIABLE CONDITIONS DEPENDING UPON SHOWER AND FOG DEVELOPMENT. BETTER SHOT FOR IFR VSBYS IN FOG ALONG S COAST ON S-SW WINDS AND MILD TEMPS MAINLY AFTER MIDNIGHT. SCT SHOWERS/TSTMS ACROSS MOST OF THE REGION THOUGH BEST SHOT ACROSS CENTRAL AND WESTERN AREAS...WITH MVFR-IFR CIGS/VSBYS. MAY SEE LOCAL HEAVY DOWNPOURS. LOW CONFIDENCE ON TIMING AND PLACEMENT. THURSDAY...MODERATE CONFIDENCE IN TRENDS. VERY UNSETTLED PATTERN AHEAD OF APPROACHING COLD FRONT. VARIABLE CONDITIONS BETWEEN VFR AND MVFR/IFR IN SHRA/TSRA/PATCHY FOG. COLD FRONT CROSSES THE REGION THU NIGHT...SO WILL SEE IMPROVING CONDITIONS ACROSS WESTERN AREAS AFTER MIDNIGHT THU NIGHT...THEN INTO CENTRAL SECTIONS AFTER 06Z-07Z. MAY SEE SW WIND GUSTING UP TO 20-25 KT DURING THE DAY AS WELL. WINDS SHIFT TO W-NW ACROSS CENTRAL AND WESTERN AREAS AFTER MIDNIGHT. KBOS TERMINAL...MODERATE CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN TIMING OF LOWER CONDITIONS AND CONVECTION THIS AFTERNOON. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO TIMING OF CONVECTION THIS AFTERNOON. COULD SEE BRIEF IFR IN A BAND OF TSRA. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... THURSDAY NIGHT INTO FRIDAY...LOW CONFIDENCE. MODERATE CONFIDENCE ON SEA BREEZE DEVELOPMENTS. VERY UNSETTLED PATTERN WITH VARIABILITY BETWEEN VFR CONDITIONS AND MVFR/IFR CONDITIONS IN SHRA/TSRA/FOG. IMPROVING CONDITIONS LATE FRIDAY NIGHT INTO SATURDAY MORNING. SATURDAY-SUNDAY...HIGH CONFIDENCE. VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TONIGHT. WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH TODAY. INCREASING SW FLOW WILL RESULT IN SEAS BUILDING OVER THE SOUTHERN COASTAL WATERS. SMALL CRAFT ADVISORY ISSUED FOR LATER TODAY INTO THURSDAY FOR COASTAL WATERS WHERE CONFIDENCE IS HIGHEST. WINDS SHOULD CONTINUE TO INCREASE TONIGHT INTO THURSDAY AS A LOW PRESSURE MOVES INTO THE GREAT LAKES. AS SUCH COULD SEE SMALL CRAFT ADVISORY EXPAND INTO MORE OF THE COASTAL WATERS AROUND CAPE COD DUE TO 25 KT WIND GUSTS. CONFIDENCE IS NOT YET HIGH ENOUGH TO ISSUE ADVISORIES FOR THOSE WATERS AT THIS TIME. EXPECT LOW VSBYS IN HEAVY SHOWERS AND PATCHY FOG AT TIMES. ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE AS WELL...ESPECIALLY NEAR SHORE. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... FRIDAY...MODERATE TO HIGH CONFIDENCE. COLD FRONT WILL BE SLOW TO CLEAR THE WATERS...SO EXPECT SW WINDS IN PLACE FOR A PORTION OF THE DAY BEFORE SHIFTING TO W-NW ACROSS THE EASTERN WATERS. THE WEEKEND...MODERATE CONFIDENCE. SEAS WILL REMAIN ABOVE SCA FOR MOST OF THE WEEKEND ESP FOR THE OUTER WATERS. GUSTY NW BEHIND THE FRONT WILL BRING GUSTS CLOSE TO GALE FORCE SAT INTO SAT NIGHT. EXPECT BOTH SEAS AND WIND TO SLOWLY SUBSIDE THROUGHOUT THE DAY ON SUNDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THURSDAY FOR ANZ255-256. SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 PM EDT THURSDAY FOR ANZ235-254. SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EDT THURSDAY FOR ANZ237. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...BELK/DUNTEN SHORT TERM...BELK LONG TERM...DUNTEN AVIATION...BELK/DUNTEN MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
627 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... TSTMS HAVE ENDED AND ONLY SCT -SHRA REMAIN MAINLY OVER S VT AND BERKSHIRE COUNTY. SOME ISOLD -SHRA ARE ALONG THE S TIER. FOR THE NEXT SVRL HOURS MOST OF THIS ACTIVITY WILL DIMINISH AND END. CLOUDS OVER MUCH OF FCA WILL THIN WITH INCRG SUNSHINE FOR A FEW HRS. THE HOOSIC RIVER AND SOME SMALL STREAMS IN SOUTHERN VERMONT HAVE REACHED BANKFUL AND MAY BRIEFLY EXCEED FLOOD THIS MORNING BEFORE RECEDING. WARNINGS AND ADVISORIES HAVE BEEN ISSUED TO COVER THESE SITUATIONS. AT SFC WMFNT IS N OF FCA. IT WILL MOVE TO ST LAWRENCE VLY TO MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL LLVL MOISTURE/CLOUDS FM TUES CONVECTION WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF 1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY. NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN. GOING TO HRRR FOR THE LATE AFTN: POU/ALB/GFL CAPE 2000/1812/1777 J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2 STORM SPEED 24/18/18 SRH 175/156/106 MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN CAPE AROUND 1000-1200 J/KG. PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL WITH VALUES OF 1.50-1.8 INCHES. SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED TIME OF LATER IN THE AFTN AND EVENING. CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE 60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY. REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT. BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS. HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT. BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF LINGERING SKIES MAY ONLY BE PS SAT IN GFS. TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS A FEW DEG...OR HOLDING STEADY. THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT. THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND WITH PERIODS OF RAW CHILLY RAIN. THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A FALL LIKE MEMORIAL DAY WEEKEND. WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT. && .LONG TERM /SUNDAY THROUGH TUESDAY/... THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER. GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20 MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD. ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM GRT PLAINS TO GRTLKS. PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND ABV BY TUESDAY AND WED. WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID. THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY... GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT 07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN. ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW 1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000 FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND TRENDS CHANGE. VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING. MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE TOMORROW AFTERNOON AND EVENING. WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING. OUTLOOK... WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN. WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF AND KPOU CHC -SHRA/-TSRA. THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY. THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG. FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM. SAT-SUN...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL CONTINUE INTO FRIDAY. RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON. WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING SOUTHWEST AROUND 10MPH THURSDAY. && .HYDROLOGY... PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN BANK RISES ARE LIKELY IN LARGER RIVERS. 3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY. DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS... BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS WILL THIS AFTERNOON INTO THURSDAY NIGHT. 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...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...NAS FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS ALBANY NY
550 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... TSTMS HAVE ENDED AND ONLY SCT -SHRA REMAIN MAINLY OVER S VT AND BERKSHIRE COUNTY. SOME ISOLD -SHRA ARE ALONG THE S TIER. FOR THE NEXT SVRL HOURS MOST OF THIS ACTIVITY WILL DIMINISH AND END. CLOUDS OVER MUCH OF FCA WILL THIN WITH INCRG SUNSHINE FOR A FEW HRS. THE HOOSIC RIVER AND SOME SMALL STREAMS IN SOUTHERN VERMONT HAVE REACHED BANKFUL AND MAY BRIEFLY EXCEED FLOOD THIS MORNING BEFORE RECEDING. WARNINGS AND ADVISORIES HAVE BEEN ISSUED TO COVER THESE SITUATIONS. AT SFC WMFNT IS N OF FCA. IT WILL MOVE TO ST LAWRENCE VLY TO MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL LLVL MOISTURE/CLOUDS FM TUES CONVECTION WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF 1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY. NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN. GOING TO HRRR FOR THE LATE AFTN: POU/ALB/GFL CAPE 2000/1812/1777 J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2 STORM SPEED 24/18/18 SRH 175/156/106 MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN CAPE AROUND 1000-1200 J/KG. PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL WITH VALUES OF 1.50-1.8 INCHES. SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED TIME OF LATER IN THE AFTN AND EVENING. CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE 60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY. REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT. BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS. HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT. BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF LINGERING SKIES MAY ONLY BE PS SAT IN GFS. TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS A FEW DEG...OR HOLDING STEADY. THE GFS/NAM ARE PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT. THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND WITH PERIODS OF RAW CHILLY RAIN. THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A FALL LIKE MEMORIAL DAY WEEKEND. WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT. && .LONG TERM /SUNDAY THROUGH TUESDAY/... THE ECMWF KEEPS THE 500HPA CUTOFF OVER RGN AND SFC LOW NEAR NEW ENGLAND COAST FOR A RAW CHILLY WEEKEND...FINALLY CLEARING ON MONDAY. HWVR AT THIS TIME ITS TO BE CONSIDERED AN OUTLIER. GFS/NAM/HPC PROGRESSIVELY MOVE THIS SYSTEM ALONG. 17 OF 20 MEMBERS OF THE GEFS ENSEMBLE KEEP IT DRY FROM FRI NIGHT ONWARD. ONLY 3 HAVE ANY QPF. SO THE WORST CASE IN THE GFS IS SOME CLOUDS FOR SUNDAY MRNG. OVERALL THE SFC HIGH BUILDS INTO THE GRTLKS SHIFTING SLOWLY EAST TO FCA BY TUES. AT 500 HPA RIDGE BUILDS FROM GRT PLAINS TO GRTLKS. PERIOD WILL START OFF PARTLY CLOUDY W/BLO NORMAL TEMPS AND A BREEZE CONTINUING SUNDAY. SCT FROST AND FREEZE WILL BE POSSIBLE IN THE HIR TRRN. IN TIME THIS WILL GIVE WAY TO BRILLIANT SUNSHINE MONDAY AND TUESDAY...LIGHT WINDS AND TEMPS RETURNING TO NORMAL MONDAY AND ABV BY TUESDAY AND WED. WILL POPULATE WITH HPC MIDNIGHT SHIFT GUID. THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY... GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT 07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN. ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW 1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000 FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND TRENDS CHANGE. VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING. MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE TOMORROW AFTERNOON AND EVENING. WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING. OUTLOOK... WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN. WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF AND KPOU CHC -SHRA/-TSRA. THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY. THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG. FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM. SAT-SUN...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL CONTINUE INTO FRIDAY. RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON. WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING SOUTHWEST AROUND 10MPH THURSDAY. && .HYDROLOGY... PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN BANK RISES ARE LIKELY IN LARGER RIVERS. 3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY. DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS... BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS WILL THIS AFTERNOON INTO THURSDAY NIGHT. 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...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...SNYDER AVIATION...NAS FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
411 AM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL MOVE BACK NORTH AS A WARM FRONT TODAY. WARM AND HUMID CONDITIONS CONTINUE INTO THURSDAY AND FRIDAY WITH SHOWERS AND SCATTERED STRONG THUNDERSTORMS POSSIBLE. COOLER AND LESS HUMID CONDITIONS ARE EXPECTED FOR THIS HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE NORTHEAST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 4 AM UPDATE... CONTINUING TO MONITOR WAVES OF CONVECTION THIS MORNING. LATEST RUNS OF THE HRRR APPEAR TO HAVE THE BEST HANDLE ON THESE BANDS OF CONVECTION...ALTHOUGH ITS TIMING WAS SLOW BY A FEW HOURS. LEANED HEAVILY ON THE 05Z HRRR WITH THE APPROPRIATE TIMING ADJUSTMENT FOR THE EARLY MORNING FORECAST. SHOWERS AND THUNDERSTORMS ARE REASONABLY HOLDING TOGETHER IN A HIGH SHEAR/LOW CAPE ENVIRONMENT. LATER TODAY...EXPECTING THE STALLED BACK-DOOR COLD FRONT TO MOVE BACK NORTH AS A WARM FRONT. THERE ARE STILL SOME QUESTIONS AS TO HOW FAST THIS WILL HAPPEN. CURRENTLY THINKING THERE IS NOT ENOUGH PUSH TO DRIVE IT COMPLETELY THROUGH SOUTHERN NEW ENGLAND. AS SUCH...MAINTAINED COASTAL SEABREEZE FRONTS ALONG BOTH COASTS. THIS HAS BIG RAMIFICATIONS FOR TEMPERATURES ALONG THE EAST COAST. SHOULD THIS FRONT GET ENOUGH PUSH...CURRENT FORECAST TEMPERATURES ARE LIKELY 5-10 DEGREES TOO LOW ALONG THE IMMEDIATE COASTLINE. AM MORE CONFIDENT WITH TEMPERATURES FARTHER INLAND. SHOULD THERE BE MORE SUNSHINE THAT CURRENTLY THINKING...LIKELY TOO LOW FARTHER INLAND AS WELL. THINKING THERE WILL BE MORE CLOUDS THAN SUNSHINE TODAY OWING TO LOTS OF CONVECTIVE DEBRIS FROM THE OVERNIGHT SHOWERS...AS WELL AS NEW CONVECTIVE CLOUDS AS WE HEAD INTO THIS AFTERNOON. MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED LATER TODAY. THERE IS THE POSSIBILITY FOR MORE ISOLATED SEVERE WEATHER. THE GREATEST RISK SHOULD BE FARTHER WEST OF OUR REGION WHERE THE MORE FAVORABLE COMBINATION OF INSTABILITY AND SHEAR SHOULD BE. THE BEST ADVICE IS TO KEEP AN EYE ON THE SKY AND LATER FORECASTS IF YOU WILL BE OUTDOORS THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... TONIGHT...MORE OF THE SAME TONIGHT. WARM FRONT CONTINUES TO PUSH NORTH AS STRONGER SOUTH TO SOUTHWEST SYNOPTIC FLOW DEVELOPS. DECENT INSTABILITY PERSISTS THROUGH THE NIGHT. SO THINKING WE WILL BE SEEING ANOTHER NIGHT OF ISOLATED TO SCATTERED THUNDERSTORMS. THE GREATEST RISK OF THESE WILL BE ACROSS THE INTERIOR...AWAY FROM THE STABILIZING INFLUENCE OF THE OCEAN. THURSDAY...SOUTHERN NEW ENGLAND REMAINS IN THE WARM SECTOR OF A LOW PRESSURE MOVING FROM THE GREAT LAKES INTO THE SAINT LAWRENCE RIVER VALLEY. THIS LOW HAS A RATHER AMPLIFIED UPPER SYSTEM...SO ITS COLD FRONT WILL BE SLOW TO MOVE ACROSS OUR REGION. EXPECTING MORE ROUNDS OF SHOWERS AND SCATTERED THUNDERSTORMS. VERY HUMID AIRMASS IN PLACE AS WELL...WITH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES. WILL LIKELY SEE SOME HEAVY DOWNPOURS WITH SOME SHOWERS...ALONG WITH SOME HAIL AND GUSTY WINDS. MAY NOT QUITE REACH SEVERE THRESHOLDS AS CLOUDS WILL BE MORE PREVALENT... THUS TEMPERATURES SHOULD BE LOWER THAN WEDNESDAY. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * SCATTERED SHOWERS AND THUNDERSTORMS FRIDAY * COOLER AND LESS HUMID FOR THE WEEKEND CONFIDENCE LEVEL/MODEL GUIDANCE...MODERATE CONFIDENCE IN OVERALL FORECAST. 00Z MODELS CONTINUE TO SLOW DOWN THE ELONGATED TROUGH MOVING ACROSS THE EASTERN HALF OF THE CONUS. THERE IS STILL SOME TIMING DIFFERENCES ON WHEN THE SYSTEM WILL PUSH THROUGH THE NORTHEAST. REGARDLESS APPEARS THAT ELONGATED TROUGH WILL MOVE INTO NEW ENGLAND EVENTUALLY BECOMING A CUTOFF LOW BY THE WEEKEND. THIS LOW WILL EVENTUALLY MOVE INTO THE MARITIMES BY THE BEGINNING OF THE WORK WEEK AS HIGH PRESSURE MOVES IN. HAVE HIGH CONFIDENCE THAT PRECIP WILL OCCUR ON FRIDAY AND COOLER TEMPS WILL DOMINATE THE REGION FOR THE WEEKEND. LOW CONFIDENCE IN FORECAST AFTER TUES. DETAILS... THURSDAY NIGHT INTO FRIDAY... UPPER LEVEL TROUGH WILL PUSH THROUGH THE EASTERN GREAT LAKES REGION EVENTUALLY PUSHING A COLD FRONT THROUGH SOUTHERN NEW ENGLAND. MODELS CONTINUE TO SLOW THE TIMING OF THE FRONT DOWN...SO BELIEVE THAT IT MOVE THROUGH SOMETIME ON FRIDAY. BECAUSE OF THE MODEL DIFFERENCE HAVE LOW CONFIDENCE IN TIMING. REGARDLESS...BELIEVE THAT SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH WITH TEMPS NEAR AVG. CANNOT RULE OUT A FEW STRONG THUNDERSTORMS ESPECIALLY ACROSS REGIONS SOUTH OF THE I-84 CORRIDOR. MODELS INDICATE SOME INSTABILITY WITH ABOUT 25KTS OF SHEAR. PWAT VALUES OF OVER 1.5 INCHES LEADS FORECASTER TO BELIEVE THAT HEAVY DOWNPOURS IS THE MAIN THREAT...BUT WITH FALLING HEIGHTS AS COLD FRONT APPROACHES...SMALL HAIL AND GUSTY WINDS IS NOT OUT OF THE QUESTION. ANY CHANCE FOR STRONG STORMS TO DEVELOP WILL DIMINISH AFTER SUNSET AS DIURNAL HEATING IS LOST. WEEKEND...TRICKY FORECAST IS PLAYING OUT FOR THE WEEKEND. MODELS HAVE INDICATED THAT THE ELONGATED TROUGH WILL CUT OFF OVER THE MID ATLANTIC AND SLOWLY ROTATE OVER NEW ENGLAND FOR THE WEEKEND. THIS WILL ALLOW FOR MUCH COOLER AIR...WELL BELOW AVG AND EVEN HAS SLOWED DOWN THE TIMING OF PRECIP. BELIEVE THAT PRECIP MAY LINGER INTO SAT...BUT HAVE LOW CONFIDENCE THAT PRECIP WILL OCCUR ON SUNDAY. FOR NOW HAVE CONTINUED WITH THE SLOW DOWN TREND IN THE FORECAST. EXPECT HIGHS REACHING INTO THE MID TO UPPER 60S WITH LOWS DROPPING INTO THE MID TO UPPER 30S. IF SKIES CLEAR OUT AS THIS COLD POOL SITS OVER US...THERE IS A POSSIBILITY THAT FROST/FREEZE HEADLINES MAY BE NEEDED AS THE ENTIRE REGION IS OFFICIALLY IN THE GROWING SEASON. MONDAY AND BEYOND...SURFACE HIGH PRESSURE WILL BE IN CONTROL FOR THE FIRST HALF OF NEXT WEEK. THIS WILL HELP TEMPS REACH SEASONAL CONDITIONS. APPEARS THAT THERE IS LIMITED MOISTURE KEEPING THE FORECAST DRY...HOWEVER CANNOT RULE OUT A SPOT SHOWER OR TWO...ESP IF SEA BREEZES DEVELOPS. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW...MODERATE CONFIDENCE IN TIMING AND AREAL COVERAGE OF STRATUS AND FOG THROUGH THIS MORNING. THROUGH 12Z...EXPECTING BANDS OF STRONG ENOUGH CONVECTION TO AVOID. THESE BANDS OF CONVECTION SHOULD CONTINUE TO WEAKEN AS IT MOVES EAST. MIXED CONDITIONS THIS MORNING WITH WIDESPREAD IFR ACROSS THE MA COASTAL PLAIN AND MUCH OF RI AND NORTHERN CT...IMPROVING TO POCKETS OF MVFR ACROSS THE INTERIOR. EVEN SOME LOCALIZED VFR POSSIBLE. TODAY...EXPECT MVFR-LIFR CONDITIONS TO GRADUALLY IMPROVE TO VFR 14-16Z AS SW WINDS DEVELOP. IFR MAY PERSIST MOST OF THE DAY AT KACK. ISOLATED TO SCATTERED CONVECTION BECOMING MORE WIDESPREAD THIS AFTERNOON...ESPECIALLY WEST OF KMHT-KORH-KIJD. TONIGHT...MODERATE CONFIDENCE IN TRENDS. EXPECT VARIABLE CONDITIONS DEPENDING UPON SHOWER AND FOG DEVELOPMENT. BETTER SHOT FOR IFR VSBYS IN FOG ALONG S COAST ON S-SW WINDS AND MILD TEMPS MAINLY AFTER MIDNIGHT. SCT SHOWERS/TSTMS ACROSS MOST OF THE REGION THOUGH BEST SHOT ACROSS CENTRAL AND WESTERN AREAS...WITH MVFR-IFR CIGS/VSBYS. MAY SEE LOCAL HEAVY DOWNPOURS. LOW CONFIDENCE ON TIMING AND PLACEMENT. THURSDAY...MODERATE CONFIDENCE IN TRENDS. VERY UNSETTLED PATTERN AHEAD OF APPROACHING COLD FRONT. VARIABLE CONDITIONS BETWEEN VFR AND MVFR/IFR IN SHRA/TSRA/PATCHY FOG. COLD FRONT CROSSES THE REGION THU NIGHT...SO WILL SEE IMPROVING CONDITIONS ACROSS WESTERN AREAS AFTER MIDNIGHT THU NIGHT...THEN INTO CENTRAL SECTIONS AFTER 06Z-07Z. MAY SEE SW WIND GUSTING UP TO 20-25 KT DURING THE DAY AS WELL. WINDS SHIFT TO W-NW ACROSS CENTRAL AND WESTERN AREAS AFTER MIDNIGHT. KBOS TERMINAL...MODERATE CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN TIMING OF LOWER CONDITIONS AND CONVECTION THIS AFTERNOON. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO TIMING OF CONVECTION THIS AFTERNOON. COULD SEE BRIEF IFR IN A BAND OF TSRA. APPEARS THIS BAND WILL PASS TO THE NORTH OF THE TERMINAL THROUGH 0830Z. WILL CONTINUE TO MONITOR. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... THURSDAY NIGHT INTO FRIDAY...LOW CONFIDENCE. MODERATE CONFIDENCE ON SEA BREEZE DEVELOPMENTS. VERY UNSETTLED PATTERN WITH VARIABILITY BETWEEN VFR CONDITIONS AND MVFR/IFR CONDITIONS IN SHRA/TSRA/FOG. IMPROVING CONDITIONS LATE FRIDAY NIGHT INTO SATURDAY MORNING. SATURDAY-SUNDAY...HIGH CONFIDENCE. VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TONIGHT. WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH TODAY. INCREASING SW FLOW WILL RESULT IN SEAS BUILDING OVER THE SOUTHERN COASTAL WATERS. SMALL CRAFT ADVISORY ISSUED FOR LATER TODAY INTO THURSDAY FOR COASTAL WATERS WHERE CONFIDENCE IS HIGHEST. WINDS SHOULD CONTINUE TO INCREASE TONIGHT INTO THURSDAY AS A LOW PRESSURE MOVES INTO THE GREAT LAKES. AS SUCH COULD SEE SMALL CRAFT ADVISORY EXPAND INTO MORE OF THE COASTAL WATERS AROUND CAPE COD DUE TO 25 KT WIND GUSTS. CONFIDENCE IS NOT YET HIGH ENOUGH TO ISSUE ADVISORIES FOR THOSE WATERS AT THIS TIME. EXPECT LOW VSBYS IN HEAVY SHOWERS AND PATCHY FOG AT TIMES. ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE AS WELL...ESPECIALLY NEAR SHORE. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... FRIDAY...MODERATE TO HIGH CONFIDENCE. COLD FRONT WILL BE SLOW TO CLEAR THE WATERS...SO EXPECT SW WINDS IN PLACE FOR A PORTION OF THE DAY BEFORE SHIFTING TO W-NW ACROSS THE EASTERN WATERS. THE WEEKEND...MODERATE CONFIDENCE. SEAS WILL REMAIN ABOVE SCA FOR MOST OF THE WEEKEND ESP FOR THE OUTER WATERS. GUSTY NW BEHIND THE FRONT WILL BRING GUSTS CLOSE TO GALE FORCE SAT INTO SAT NIGHT. EXPECT BOTH SEAS AND WIND TO SLOWLY SUBSIDE THROUGHOUT THE DAY ON SUNDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THURSDAY FOR ANZ255-256. SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 PM EDT THURSDAY FOR ANZ235-254. SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EDT THURSDAY FOR ANZ237. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...BELK SHORT TERM...BELK LONG TERM...DUNTEN AVIATION...BELK/DUNTEN MARINE...BELK/DUNTEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
321 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... LINE OF THUNDERSTORMS EAST OF I-88 CORRIDOR MOVING THROUGH FCA ATTM. MAINLY HEAVY RAIN AND FREQ LIGHTNING. AREAS OF MODERATE RAIN EXTEND BEHIND IT. MOST AREAS TO BE IMPACTED WILL SEE ANOTHER 0.5 TO 1.O INCH OF RAIN BRINGING TOTALS FOR TODAY UP TO 2-3 INCHES IN MOST AREAS IMPACTED WITH SOME ISOLD 4 INCH AMOUNTS. AREAL FLOOD ADVISORY HAS BEEN ISSUED FROM MHWK VLY AND ADJACENT AREAS INTO S VT/BERKSHIRE COUNTY FOR OVERNIGHT TO COVER ANY SMALL STREAM AND URBAN FLOODING. THIS LINE SHOULD EXIT MOST OF UPSTATE NY/VT AND W MA NEXT 1.5 TO 2 HRS...EXCEPT CATSKILLS AND MID HUDSON VLY WHERE IT IS JUST ARRIVING IN AREAS THAT HAVE NOT HAD MUCH PCPN AT ALL OR SINCE SINCE LATE TUES AFTN. IT SHOULD THEN DIMINISH AND END OVERNIGHT AT SFC WMFNT IS LIFTING NE THROUGH FCA OVERNIGHT AND WILL BE ALONG N TIER OR N OF RGN WED MRNG. IT WILL MOVE TO ST LAWRENCE VLY TO MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL LLVL MOISTURE/CLOUDS FM TUES CONVECTION WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF 1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY. NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN. GOING TO HRRR FOR THE LATE AFTN: POU/ALB/GFL CAPE 2000/1812/1777 J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2 STORM SPEED 24/18/18 SRH 175/156/106 MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN CAPE AROUND 1000-1200 J/KG. PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL WITH VALUES OF 1.50-1.8 INCHES. SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED TIME OF LATER IN THE AFTN AND EVENING. CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE 60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... THU AND THU NT 500HPA TROF STARTS MOVING E THROUGH GRTLKS AS SFC LOW ORGANIZES ALONG SEMI-STALLED FRONT FROM FM LK ERIE UP ST LAWRENCE VLY. THIS SYSTEM PUSHES SLOWLY EAST DRAGGING A CDFNT TO BTV-SYR LINE THU AFTN...AND THROUGH FCA BY 12UTC FRI. NAM/GFS IN PRETTY CLOSE AGREEMENT WITH THIS TIMING. WHILE THERE IS INCRG DYNAMICS WITH APPROACHING JET AND TROF...CAPES 1000-1500 ...CLOUDS WILL BE WIDESPREAD HOLDING MAX TEMPS TO MID 70S TO AROUND 80. SPC HAS ONLY PUT AREA IN SEE TEXT ATTM...WITH LOW PROBS DUE TO LIMITED INSTABILITY. REGARDLESS AREA WILL SEE PERIOD OF -SHRA/TSTMS INCRG THU...TRANSITIONING TO -SHRA/-RA BEHIND THE CDFNT OVERNIGHT. BY FRI MORNING CDFNT WILL BE IN I-95 CORRIDOR ALONG THE ATLC COAST. 500HPA TROF WILL BE MOVING INTO NE USA...AND BOTH MODELS DEVELOP A MODEST SFC LOW OVER NJ. THE WARMTH OF PAST FEW DAYS WILL GIVE WAY TO A COOL BREEZY WITH -SHRA FRI. FINALLY SFC LOW MOVES OFFSHORE FRI NT AS HIGH PRESSURE BUILDS INTO THE GRTLKS. HWVR THE 500HPA TROF LINGERS AND CUTS OFF OVER NEW ENG SAT. BETWEEN THESE TWO SYSTEMS A BRISK NW GRADIENT WILL DRIVE SOME PRETTY COOL AIR INTO THE REGION FOR LATE MAY. WITH 500HPA CUT OFF LINGERING SKIES MAY ONLY BE PS SAT IN GFS. TEMPS WILL PROBABLY GO NOWHERE FRI...ONLY COMING OFF MORNING LOWS A FEW DEG...OR HOLDING STEADY. THE WEEKEND FCST IS DETERIORATING... THE GFS IS PROGRESSIVE WITH SFC LOW DEPARTING THE COAST FRI NT...WITH ITS 500 HPA TROF CROSSING REGION SAT AND DEPARTING SAT NT WITH PC SKIES AND A RATHER BRISK WIND GRADIENT. THE 00UTC ECMWF CUTS OFF THE 500HPA LOW OVER NJ...DEVELOPS A COASTAL LOW...WHICH LINGERS ALONG THE EAST COAST FOR THE WEEKEND WITH PERIODS OF RAW CHILLY RAIN. THE GFS TEMPS WOULD BRING MINS SAT MORNING INTO THE MID 30S TO MID 40S WITH SOME NEAR 30 AND POTENTIAL FROST/FREEZE ISSUES IN ADRNDKS. HIGHS SAT WILL ONLY REBOUND EVEN WITH THE STRONG SUN TO THE 60S. LOWS SAT NIGHT WOULD AGAIN BE IN THE 30S. WINDS WILL REMAIN BRISK. ECMWF WOULD RESULT IN SLIGHTLY WARMER NIGHT TIME TEMPS AND COOLER YET DAYTIME TEMPS IN MID 50S TO LOW 60S. HPC LEANS TWRD A BLEND WITH CHC POPS LINGERING INTO SAT. IT WILL BE A FALL LIKE MEMORIAL DAY WEEKEND. WILL LEAN TWRD GFS/HPC BLEND THROUGH SAT. ATTM WILL MAKE NO CHANGES BEYOND SAT NT TO MINIMIZE FLIP FLOPPING GIVEN THE SPREAD IN MODELS SOLUTIONS ATTM. && .LONG TERM /SUNDAY THROUGH TUESDAY/... CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION SUNDAY. THE HIGH WILL SHIFT EASTWARD ACROSS THE REGION AND OFFSHORE EARLY NEXT WEEK. TEMPERATURES WILL GRADUALLY MODERATE AS THE HIGH SHIFTS TO THE EAST WITH NEAR SEASONABLE TEMPERATURES FOR MONDAY. THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY... GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT 07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN. ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW 1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000 FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND TRENDS CHANGE. VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING. MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE TOMORROW AFTERNOON AND EVENING. WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING. OUTLOOK... WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN. WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF AND KPOU CHC -SHRA/-TSRA. THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY. THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG. FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM. SAT-SUN...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL CONTINUE INTO FRIDAY. RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON. WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING SOUTHWEST AROUND 10MPH THURSDAY. && .HYDROLOGY... PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN BANK RISES ARE LIKELY IN LARGER RIVERS. 3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY. DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS... BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS WILL THIS AFTERNOON INTO THURSDAY NIGHT. 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...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...IAA AVIATION...NAS FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
241 AM EDT WED MAY 22 2013 .SYNOPSIS... A STALLED FRONT WILL MOVE BACK NORTH AS A WARM FRONT TODAY. WARM AND HUMID CONDITIONS CONTINUE INTO THURSDAY AND FRIDAY WITH SHOWERS AND SCATTERED STRONG THUNDERSTORMS POSSIBLE. COOLER AND LESS HUMID CONDITIONS ARE EXPECTED FOR THIS HOLIDAY WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE NORTHEAST. && .NEAR TERM /THROUGH TODAY/... 2 AM UPDATE... CONTINUING TO MONITOR WAVES OF CONVECTION THIS MORNING. LATEST RUNS OF THE HRRR APPEAR TO HAVE THE BEST HANDLE ON THESE BANDS OF CONVECTION...ALTHOUGH ITS TIMING WAS SLOW BY A FEW HOURS. LEANED HEAVILY ON THE HRRR WITH THE APPROPRIATE TIMING ADJUSTMENT FOR THE EARLY MORNING FORECAST. SHOWERS AND THUNDERSTORMS ARE REASONABLY HOLDING TOGETHER IN A HIGH SHEAR/LOW CAPE ENVIRONMENT. LATER TODAY...EXPECTING THE STALLED BACK-DOOR COLD FRONT TO MOVE BACK NORTH AS A WARM FRONT. THERE ARE STILL SOME QUESTIONS AS TO HOW FAST THIS WILL HAPPEN. CURRENTLY THINKING THERE IS NOT ENOUGH PUSH TO DRIVE IT COMPLETELY THROUGH SOUTHERN NEW ENGLAND. AS SUCH...MAINTAINED COASTAL SEABREEZE FRONTS ALONG BOTH COASTS. THIS HAS BIG RAMIFICATIONS FOR TEMPERATURES ALONG THE EAST COAST. SHOULD THIS FRONT GET ENOUGH PUSH...CURRENT FORECAST TEMPERATURES ARE LIKELY 5-10 DEGREES TOO LOW ALONG THE IMMEDIATE COASTLINE. AM MORE CONFIDENT WITH TEMPERATURES FARTHER INLAND. SHOULD THERE BE MORE SUNSHINE THAT CURRENTLY THINKING...LIKELY TOO LOW FARTHER INLAND AS WELL. THINKING THERE WILL BE MORE CLOUDS THAN SUNSHINE TODAY OWING TO LOTS OF CONVECTIVE DEBRIS FROM THE OVERNIGHT SHOWERS...AS WELL AS NEW CONVECTIVE CLOUDS AS WE HEAD INTO THIS AFTERNOON. MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED LATER TODAY. THERE IS THE POSSIBILITY FOR MORE ISOLATED SEVERE WEATHER. THE GREATEST RISK SHOULD BE FARTHER WEST OF OUR REGION WHERE THE MORE FAVORABLE COMBINATION OF INSTABILITY AND SHEAR SHOULD BE. THE BEST ADVICE IS TO KEEP AN EYE ON THE SKY AND LATER FORECASTS IF YOU WILL BE OUTDOORS THIS AFTERNOON. && .SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/... TONIGHT...MORE OF THE SAME TONIGHT. WARM FRONT CONTINUES TO PUSH NORTH AS STRONGER SOUTH TO SOUTHWEST SYNOPTIC FLOW DEVELOPS. DECENT INSTABILITY PERSISTS THROUGH THE NIGHT. SO THINKING WE WILL BE SEEING ANOTHER NIGHT OF ISOLATED TO SCATTERED THUNDERSTORMS. THE GREATEST RISK OF THESE WILL BE ACROSS THE INTERIOR...AWAY FROM THE STABILIZING INFLUENCE OF THE OCEAN. THURSDAY...SOUTHERN NEW ENGLAND REMAINS IN THE WARM SECTOR OF A LOW PRESSURE MOVING FROM THE GREAT LAKES INTO THE SAINT LAWRENCE RIVER VALLEY. THIS LOW HAS A RATHER AMPLIFIED UPPER SYSTEM...SO ITS COLD FRONT WILL BE SLOW TO MOVE ACROSS OUR REGION. EXPECTING MORE ROUNDS OF SHOWERS AND SCATTERED THUNDERSTORMS. VERY HUMID AIRMASS IN PLACE AS WELL...WITH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES. WILL LIKELY SEE SOME HEAVY DOWNPOURS WITH SOME SHOWERS...ALONG WITH SOME HAIL AND GUSTY WINDS. MAY NOT QUITE REACH SEVERE THRESHOLDS AS CLOUDS WILL BE MORE PREVALENT... THUS TEMPERATURES SHOULD BE LOWER THAN WEDNESDAY. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * SHOWERS AND SCATTERED THUNDERSTORMS THURSDAY INTO FRIDAY * COOLER AND LESS HUMID FOR THE HOLIDAY WEEKEND INTO EARLY NEXT WEEK OVERVIEW AND MODEL PREFERENCES... MEDIUM RANGE OPERATIONAL MODEL SUITE SIGNALING AN AMPLIFIED... SLOWLY PROGRESSIVE PATTERN ACROSS THE LOWER 48. AT THE START... NOTING LONG WAVE TROUGH ACROSS THE UPPER PLAINS INTO THE WESTERN LAKES THOUGH SOME DIFFERENCES IN POSITIONING...ALONG WITH H5 CUTOFF LOW MOVING INTO THE WEST COAST. LOWER THAN AVERAGE CONFIDENCE ON THE PROGRESSION OF THE UPPER LEVEL PATTERN OPERATIONAL SUITE...THOUGH GENERAL SURFACE SYSTEM POSITIONS AND TIMING SIGNALS THROUGH THE HOLIDAY WEEKEND SEEM FAIRLY GOOD. BETTER CONTINUITY AMONGST THE MODEL ENSEMBLES...SO LEANED CLOSER TO THOSE BUT DID INCORPORATE A LITTLE OF THE 12Z GFS/00Z ECMWF INTO THE EARLY PORTION OF THE LONG TERM /WED NIGHT TO FRI/. ANTICIPATE SLOW BUT STEADY CHANGE TO THE UPPER PATTERN LATE THIS WEEK AS UPPER TROUGH MOVES ACROSS THE EASTERN U.S. FRI-SAT. THIS WILL BRING AIRMASS CHANGE AS UPPER WINDS SHIFT TO NW...BRINGING COOLER AND DRIER CONDITIONS FOR A GOOD CHUNK OF THE HOLIDAY WEEKEND. MODERATE TO HIGH CONFIDENCE CONTINUES FOR THE THU-FRI TIMEFRAME WITH PERIODIC PRECIP AND SCATTERED CONVECTION...THEN COLD FRONT SHOULD SWEEP THROUGH FRI NIGHT INTO EARLY SAT. MODERATE CONFIDENCE BEYOND FRIDAY AS MAY SEE SOME TIMING ISSUES WITH THE PASSAGE OF THE UPPER TROUGH SOMETIME SAT. FEW SHOWERS ARE POSSIBLE...BUT TIMING IS DIFFICULT. EXPECT HIGH TEMPS THIS WEEKEND TO RUN UP TO 5 DEGREES BELOW SEASONAL NORMS. DOES LOOK TO BE DRY INTO EARLY NEXT WEEK WITH CLOSE TO SEASONABLE TEMPS. DETAILS... THURSDAY NIGHT...TIMING OF A COLD FRONT IS STILL IN QUESTION. THOUGH APPEARS IT SHOULD SLOWLY CROSS THE REGION THU NIGHT...MAY REACH THE COAST BY 12Z FRI. HAVE CARRIED LIKELY TO CAT POPS AS COLD FRONT PASSES. LOOKS LIKE BEST INSTABILITY MAY PASS E OVERNIGHT...BUT COULD STILL SEE SOME ELEVATED CONVECTION SO KEPT SCT THUNDER IN THE FORECAST. TEMPS DO START DROPPING BACK TO THE LOWER-MID 50S LATE ACROSS FAR INTERIOR AREAS. FRIDAY...COLD FRONT SHOULD CLEAR THE E COAST DURING THE MORNING BUT SOME SHOWERS MAY LINGER INTO MID MORNING ACROSS E MA. OTHERWISE...EXPECT CONDITIONS TO IMPROVE THOUGH IT WILL BE NOTICEABLY COOLER AND LESS HUMID. SATURDAY THROUGH TUESDAY...BLOCKING UPPER PATTERN CONTINUES ACROSS LABRADOR INTO GREENLAND THROUGH THIS TIMEFRAME...WHICH WILL KEEP HIGH PRES BUILDING OUT OF CENTRAL CANADA DOWN THE EASTERN SEABOARD. LONG RANGE MODELS AND ENSEMBLES ARE IN PRETTY GOOD AGREEMENT WITH THIS PORTION OF THE FORECAST. EXPECT DRY AND COOL CONDITIONS THROUGH THE HOLIDAY WEEKEND INTO EARLY NEXT WEEK. ON SATURDAY...EXPECT DAYTIME HIGHS ONLY IN THE 60S...RUNNING 4 TO 8 DEGREES BELOW SEASONAL NORMS...THOUGH WILL MODIFY A BIT THROUGH THE REMAINDER OF THIS TIMEFRAME. DUE TO SEVERE WEATHER WATCH THIS AFTERNOON...KEPT PREVIOUS FORECAST GOING FROM SUNDAY ONWARD...BUT LOOKS IN GOOD SHAPE WITH LATEST MODEL GUIDANCE. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW...MODERATE CONFIDENCE IN TIMING AND AREAL COVERAGE OF STRATUS AND FOG THROUGH THIS MORNING. THROUGH 12Z...EXPECTING BANDS OF STRONG ENOUGH CONVECTION TO AVOID. THESE BANDS OF CONVECTION SHOULD CONTINUE TO WEAKEN AS IT MOVES EAST. MIXED CONDITIONS THIS MORNING WITH WIDESPREAD IFR ACROSS THE MA COASTAL PLAIN AND MUCH OF RI AND NORTHERN CT...IMPROVING TO POCKETS OF MVFR ACROSS THE INTERIOR. EVEN SOME LOCALIZED VFR POSSIBLE. TODAY...EXPECT MVFR-LIFR CONDITIONS TO GRADUALLY IMPROVE TO VFR 14-16Z AS SW WINDS DEVELOP. IFR MAY PERSIST MOST OF THE DAY AT KACK. ISOLATED TO SCATTERED CONVECTION BECOMING MORE WIDESPREAD THIS AFTERNOON...ESPECIALLY WEST OF KMHT-KORH-KIJD. TONIGHT...MODERATE CONFIDENCE IN TRENDS. EXPECT VARIABLE CONDITIONS DEPENDING UPON SHOWER AND FOG DEVELOPMENT. BETTER SHOT FOR IFR VSBYS IN FOG ALONG S COAST ON S-SW WINDS AND MILD TEMPS MAINLY AFTER MIDNIGHT. SCT SHOWERS/TSTMS ACROSS MOST OF THE REGION THOUGH BEST SHOT ACROSS CENTRAL AND WESTERN AREAS...WITH MVFR-IFR CIGS/VSBYS. MAY SEE LOCAL HEAVY DOWNPOURS. LOW CONFIDENCE ON TIMING AND PLACEMENT. THURSDAY...MODERATE CONFIDENCE IN TRENDS. VERY UNSETTLED PATTERN AHEAD OF APPROACHING COLD FRONT. VARIABLE CONDITIONS BETWEEN VFR AND MVFR/IFR IN SHRA/TSRA/PATCHY FOG. COLD FRONT CROSSES THE REGION THU NIGHT...SO WILL SEE IMPROVING CONDITIONS ACROSS WESTERN AREAS AFTER MIDNIGHT THU NIGHT...THEN INTO CENTRAL SECTIONS AFTER 06Z-07Z. MAY SEE SW WIND GUSTING UP TO 20-25 KT DURING THE DAY AS WELL. WINDS SHIFT TO W-NW ACROSS CENTRAL AND WESTERN AREAS AFTER MIDNIGHT. KBOS TERMINAL...MODERATE CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN TIMING OF LOWER CONDITIONS AND CONVECTION THIS AFTERNOON. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF...MAINLY DUE TO TIMING OF CONVECTION THIS AFTERNOON. COULD SEE BRIEF IFR IN A BAND OF TSRA. APPEARS THIS BAND WILL PASS TO THE NORTH OF THE TERMINAL THROUGH 0830Z. WILL CONTINUE TO MONITOR. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... FRIDAY...MODERATE TO HIGH CONFIDENCE. MAY SEE LEFTOVER POCKETS OF MVFR CIGS/VSBYS POSSIBLE ACROSS E MA THROUGH 14Z-15Z FRI. OTHERWISE...VFR. SATURDAY-SUNDAY...HIGH CONFIDENCE. VFR. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TONIGHT. WINDS EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH TODAY. INCREASING SW FLOW WILL RESULT IN SEAS BUILDING OVER THE SOUTHERN COASTAL WATERS. WILL ISSUE A SMALL CRAFT ADVISORY FOR ROUGH SEAS LATER TODAY INTO THURSDAY. WINDS SHOULD CONTINUE TO INCREASE TONIGHT INTO THURSDAY AS A LOW PRESSURE MOVES INTO THE GREAT LAKES. EXPECT LOW VSBYS IN HEAVY SHOWERS AND PATCHY FOG AT TIMES. ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE AS WELL...ESPECIALLY NEAR SHORE. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... FRIDAY...MODERATE TO HIGH CONFIDENCE. COLD FRONT WILL BE SLOW TO CLEAR THE WATERS...SO EXPECT SW WINDS IN PLACE FOR A PORTION OF THE DAY BEFORE SHIFTING TO W-NW ACROSS THE EASTERN WATERS. SATURDAY-SUNDAY...MODERATE CONFIDENCE. SEAS WILL REMAIN ABOVE SMALL CRAFT FOR MOST OF THE WEEKEND ESPECIALLY ON THE OUTER WATERS. NW GUSTS MAY APPROACH 25 KT. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/EVT NEAR TERM...BELK SHORT TERM...BELK LONG TERM...EVT AVIATION...BELK/EVT MARINE...BELK/EVT
AREA FORECAST DISCUSSION
NWS ALBANY NY
156 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE FROM THE GREAT LAKES REGION TODAY INTO THE SAINT LAWRENCE VALLEY THURSDAY. WARM HUMID CONDITIONS WILL PERSIST INTO THURSDAY WITH SHOWERS AND THUNDERSTORMS. THURSDAY A STRONG COLD FRONT WILL PUSH SLOWLY THROUGH NEW YORK AND NEW ENGLAND. LOW PRESSURE WILL FORM ALONG THIS FRONT ON THE COAST FRIDAY...AS MUCH COLDER AIR POURS INTO THE REGION. FRIDAY NIGHT THE STORM WILL MOVE OFFSHORE AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES REGION FOR THE MEMORIAL DAY WEEKEND. IT WILL BRING FAIR WEATHER WITH UNSEASONABLY COOL TEMPERATURES FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... LINE OF THUNDERSTORMS EAST OF I-88 CORRIDOR MOVING THROUGH FCA ATTM. MAINLY HEAVY RAIN AND FREQ LIGHTNING. AREAS OF MODERATE RAIN EXTEND BEHIND IT. MOST AREAS TO BE IMPACTED WILL SEE ANOTHER 0.5 TO 1.O INCH OF RAIN BRINGING TOTALS FOR TODAY UP TO 2-3 INCHES IN MOST AREAS IMPACTED WITH SOME ISOLD 4 INCH AMOUNTS. AREAL FLOOD ADVISORY HAS BEEN ISSUED FROM MHWK VLY AND ADJACENT AREAS INTO S VT/BERKSHIRE COUNTY FOR OVERNIGHT TO COVER ANY SMALL STREAM AND URBAN FLOODING. THIS LINE SHOULD EXIT MOST OF UPSTATE NY/VT AND W MA NEXT 1.5 TO 2 HRS...EXCEPT CATSKILLS AND MID HUDSON VLY WHERE IT IS JUST ARRIVING IN AREAS THAT HAVE NOT HAD MUCH PCPN AT ALL OR SINCE SINCE LATE TUES AFTN. IT SHOULD THEN DIMINISH AND END OVERNIGHT AT SFC WMFNT IS LIFTING NE THROUGH FCA OVERNIGHT AND WILL BE ALONG N TIER OR N OF RGN WED MRNG. IT WILL MOVE TO ST LAWRENCE VLY TO MICHIGAN LINE...AS WEAK LOW PRESSURE FORMS ALONG AND PROPAGATES UP IT TODAY. THIS LEAVES FCA IN WARM SECTOR WITH ALOT OF RESIDUAL LLVL MOISTURE/CLOUDS FM TUES CONVECTION WITH TD IN 60S...TEMPS REBOUNDING TO 80S...VRBL CLOUDS THE THREAT OF TSTMS INCREASES THROUGH THE DAY. LOCAL WRF/HRRR WHICH HANDLED TODAYS EVENT WELL...SHOW A MAINLY CELLULAR AND PULSE RESPONSE TODAY IN SIMULATED REFL. GFS PRODUCES SFC CAPES ON THE ORDER OF 1000-2000 J/KG THE NAM 2000-4000 J/KG WITH A DEFINE PREFERENCE FROM THE CAPITAL DISTRICT S & E AND THE MHWK VLY. NAM AND GFS SHOW H850-700 LAPSE RATES AROUND 6.5 THIS AFTN. GOING TO HRRR FOR THE LATE AFTN: POU/ALB/GFL CAPE 2000/1812/1777 J/KG MAX WIND 33/33/40 EHI OF 1.6/1.5/1.2 STORM SPEED 24/18/18 SRH 175/156/106 MAGLENTA 1.75/2.17/2.44 ALL MAJOR SEVERE WHICH IS CONSIDERABLY STRONGER LOOKING THAN HRRR REFL. THE NAM MODEL SOUNDINGS AND WRF MODEL SOUNDINGS ARE CONSIDERABLY LOWER IN CAPE AROUND 1000-1200 J/KG. PWATS WILL CONTINUE TO RUN A FEW STANDARD DEVIATIONS ABOVE NORMAL WITH VALUES OF 1.50-1.8 INCHES. SOME OTHER CONSIDERATIONS LLVL JET AT H850 HPA IS 25-35KTS...AND BULK OF IT MAY PASS WEST OF FCA. THERE IS LITTLE ADDITIONAL UPPER FORCING. SPC HAS OUTLOOKED NY PORTIONS OF FCA AT THIS POINT WILL NOT TRY TO GET SPECIFIC...WILL GO WITH ENHANCED WORDING TODAY. IF THERES A PREFERRED AREA IT WOULD MHWK VLY AND S...AND A PREFERRED TIME OF LATER IN THE AFTN AND EVENING. CONVECTION WILL CONTINUE INTO THE EVNG HOURS AND DIM OVERNIGHT AS FCA IS FIRMLY IN WARM SECTION. LOWS AND TD WILL BE IN THE 60S...AND AREAS OF PATCHY FOG POSSIBLE IN THE MORNING. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... THU-THU NIGHT...TRICKY FORECAST FOR STRONG TO SEVERE CONVECTION ON THU WITH THE COLD FRONT STILL TO THE WEST. THE BETTER JET DYNAMICS DURING THE AFTERNOON WITH APPRECIABLE MOISTURE AND INSTABILITY IN PLACE. THE QUESTION WILL BE HOW MUCH HEATING OCCURS WITH CLOUD COVER BEING AND ISSUE. LOCATIONS FROM THE CAPITAL DISTRICT SOUTH AND EAST MAY HAVE THE BEST CHC FOR DESTABILIZATION AND SEVERE WEATHER. NO SPC OUTLOOK YET...BUT DEFINITELY COULD SEE ONE LATER FOR PARTS OF THE REGION. WILL MENTION SOME STRONG TO SEVERE THUNDERSTORMS MAY BE POSSIBLE AGAIN ON THU. THE FRONT MOVES THROUGH SLOWLY...WITH SHOWERS PERSISTING THROUGH THE OVERNIGHT. A WEAK WAVE MOVE ALONG THE BOUNDARY TOO. THE COLD ADVECTION WILL SLOWLY SEEP INTO THE REGION WITH LOWS IN THE 50S TO L60S BY DAYBREAK FRI. HIGHS WILL GENERALLY BE IN THE 70S ON THU. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... COOLER AND DRY WEATHER EXPECTED FOR THE HOLIDAY WEEKEND. HAVE FOLLOWED THE WEATHER PREDICTION CENTER`S GUIDANCE WHICH FAVORS THE ECMWF ENSEMBLE MEAN WHICH HAS THE SUPPORT OF THE GEFS MEANS. WPC INDICATES THE DETERMINISTIC/OPERATIONAL RUNS OF THE ECMWF AND GFS DEVIATE SIGNIFICANTLY ENOUGH FROM THE STEADIER MEANS THAT THEY WERE NOT INCORPORATION INTO THEIR FORECAST. CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION AS WE HEAD INTO THE WEEKEND BEHIND THE DEPARTING LOW PRESSURE SYSTEM. WILL HAVE LINGER SHOWERS ON FRIDAY AS THE LOW PRESSURE SYSTEM MOVES OFF THE EAST. ON SATURDAY...THE REGION WILL BE UNDER CYCLONIC FLOW. THE HIGH WILL SHIFT EASTWARD ACROSS THE REGION AND OFFSHORE EARLY NEXT WEEK. SATURDAY IS EXPECTED TO BE THE COOLEST DAY WITH HIGHS MAINLY IN THE MID 50S TO MID 60S...AROUND 10 DEGREE BELOW NORMAL. TEMPERATURES WILL GRADUALLY MODERATE AS THE HIGH SHIFTS TO THE EAST WITH NEAR SEASONABLE TEMPERATURES FOR MONDAY. THE GROWING SEASON IS UNDERWAY ACROSS THE MID HUDSON VALLEY... GREATER CAPITAL DISTRICT...LAKE GEORGE SARATOGA REGION...THE MOHAWK VALLEY...EASTERN CATSKILLS...TACONICS...BERKSHIRES...BENNINGTON AND EASTERN WINDHAM COUNTIES VT AND LITCHFIELD COUNTY. IT WILL START ON MAY 25TH FOR THE SOUTHERN ADIRONDACKS AND WESTERN WINDHAM COUNTY. AT THIS TIME...NIGHTTIME LOWS FRIDAY NIGHT/SATURDAY MORNING AND SATURDAY NIGHT/SUNDAY MORNING ARE EXPECTED TO BE IN THE 40S IN THE VALLEYS AND 30S ACROSS THE HIGHER TERRAIN. WITH THE EXPANSION OF THE GROWING SEASON BY THIS TIME FROST ADVISORIES WOULD BE LIKELY NEEDED FOR THE HIGHER TERRAIN. TEMPERATURES ACROSS THE SOUTHERN ADIRONDACKS COULD BE COLDER WHICH WOULD LEAD TO THE NEED FOR A FREEZE WARNING. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... ACCOUNTING FOR CURRENT SHOWER AND THUNDERSTORM ACTIVITY THAT SHOULD CONTINUE AT KGFL THROUGH ABOUT 06Z...AT KALB THROUGH ABOUT 07Z-08Z...AND KPSF THROUGH ABOUT 08Z. SOME MVFR AND OCCASIONAL IFR CONDITIONS IN THE SHOWERS AND THUNDERSTORMS. SOME OTHER ISOLATED THUNDERSTORMS WELL WEST OF THE AREA COULD APPROACH THE AREA BETWEEN KALB AND KPOU THROUGH SUNRISE...BUT WITH CONTINUED STABILIZATION OF THE ATMOSPHERE THE THUNDERSTORMS COULD DISSIPATE BY THEN. ONCE THE RAIN ENDS EARLY THIS MORNING...THERE COULD BE PERIODS OF MVFR FOG AND VFR CEILINGS...BUT SCATTERED CLOUDS COULD DEVELOP BELOW 1000 FEET. WILL HAVE TO MONITOR FOR ANY BETTER CLEARING TOWARD SUNRISE THAT COULD RESULT IN IFR FOG AND/OR CEILINGS BELOW 1000 FEET. FOR NOW NOT INDICATING ANY IFR CONDITIONS AT ANY TAF SITES THROUGH THE EARLY MORNING HOURS...BUT WILL AMEND IF CONDITIONS AND TRENDS CHANGE. VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE DAY AFTER 12Z UNTIL NEW CONVECTION DEVELOPS LATER IN THE AFTERNOON AND EVENING. MIXED SIGNALS ABOUT WHERE THE CONCENTRATION OF THUNDERSTORMS WILL BE LATER TODAY SO PUTTING VCSH IN ALL TAFS AFTER 22Z...BUT MORE THUNDERSTORM ACTIVITY EXPECTED SCATTERED ACROSS THE REGION LATE TOMORROW AFTERNOON AND EVENING. WINDS SHOULD BE LIGHT SOUTH THROUGH SUNRISE...THEN BECOME VARIABLE AT LESS THAN 10 KT THROUGH THE DAY TOMORROW...MAINLY SOUTH TO SOUTHWEST. WINDS SHOULD BE LIGHT AGAIN TOMORROW EVENING. WINDS COULD BE QUITE GUSTY IN THUNDERSTORMS TOMORROW AFTERNOON AND EVENING. OUTLOOK... WED...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY DURING THE AFTN. WED NIGHT...VFR/MVFR. AT KGFL AND KALB -SHRA/-TSRA LIKELY. AT KPSF AND KPOU CHC -SHRA/-TSRA. THU...MVFR WITH IFR POSSIBLE. -SHRA/-TSRA LIKELY. THU NIGHT...VFR/MVFR. CHC -SHRA/-TSRA ESPECIALLY IN THE EVNG. FRI...MAINLY VFR. CHC -TSRA MAINLY IN THE AM. SAT-SUN...VFR. NO SIG WX. && .FIRE WEATHER... NO FIRE WEATHER CONCERNS THROUGH FRIDAY. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY NIGHT. SHOWERS WILL CONTINUE INTO FRIDAY. RH VALUES WILL INCREASE TO 85 TO 100 PERCENT TONIGHT...AND THURSDAY NIGHT...AND LOWER TO 45 TO 60 PERCENT THIS AFTERNOON. WINDS WILL MAINLY LESS THAN 10 MPH THROUGH TONIGHT...BECOMING SOUTHWEST AROUND 10MPH THURSDAY. && .HYDROLOGY... PWATS ON THE ORDER OF 1.5 TO 2.0 INCHES NEXT FEW DAYS. WHILE WIDESPREAD FLOODING IS NOT ANTICIPATED...LOCALLY HEAVY RAINFALL IN THUNDERSTORMS AND TRAINING COULD RESULT IN SMALL STREAM AND URBAN FLOODING OVERNIGHT AND AGAIN THIS AFTERNOON. SIGNIFICANT WITHIN BANK RISES ARE LIKELY IN LARGER RIVERS. 3-HR ZONAL FFG VALUES ARE GENERALLY IN THE 2.5-3.0 INCH RANGE AT THIS TIME...WHICH ARE HIGH FOR MID TO LATE MAY. DUE TO THE SCATTERED NATURE OF THE SHOWERS AND THUNDERSTORMS... BASIN AVERAGE QPF WILL BE HIGHLY VARIABLE THIS WEEK. THE BEST THREAT FOR SEEING SIGNIFICANT AMOUNTS OF SHOWERS OR THUNDERSTORMS WILL THIS AFTERNOON INTO THURSDAY NIGHT. 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...SNYDER NEAR TERM...SNYDER SHORT TERM...SNYDER LONG TERM...IAA/NAS AVIATION...NAS FIRE WEATHER...SNYDER HYDROLOGY...SNYDER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
146 AM EDT WED MAY 22 2013 .SYNOPSIS... A FRONTAL BOUNDARY WILL MOVE INTO THE AREA OVERNIGHT...THEN DISSIPATE WEDNESDAY MORNING. A COLD FRONT WILL THEN SLOWLY APPROACH FROM THE WEST...THEN PASS THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... HAVE UPDATED GRIDS TO REFLECT CURRENT OBSERVATION TRENDS. ADVECTION FOG/STRATUS EXPANDING INTO ERN-MOST LONG ISLAND SOUND AND NEARBY LAND AREAS. WILL CONTINUE WITH DENSE FOG ADVY FOR THE FORKS OF LONG ISLAND AND COASTAL SE CT...WITH PATCHY FOG ELSEWHERE. WATCHING LINE OF CONVECTION OVER CENTRAL NY STATE...WHICH THE RA AND HRRR SUGGEST COULD MAKE A RIGHT TURN TOWARD THE CWA OVERNIGHT INTO EARLY WED MORNING. CONVECTION APPEARS OUTFLOW-DOMINATED WHICH SUGGESTS EVENTUAL WEAKENING. HOWEVER...SINCE THAT OUTFLOW IS SOMEWHAT ALIGNED WITH THE BULK 0-3 KM SHEAR...SOME REDEVELOPMENT COULD OCCUR CLOSER TO THE HUDSON VALLEY AND INTERIOR SW CT LATE TONIGHT...SO HAVE CARRIED A SLIGHT CHANCE POP FOR ALL AREAS LATE TONIGHT INTO WED MORNING. BACK DOOR FRONT ADVANCING WWD INTO SOUTHERN CT AND EASTERN LONG ISLAND WILL LEAD TO A COOLER NIGHT THAN ORIGINALLY FORECAST...WITH LOWER 55-60. IT WILL HOWEVER REMAIN WARM AND MUGGY OVER THE HUDSON VALLEY...NYC METRO AND LONG ISLAND...WITH LOWS IN THE 60S. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... LOOKS LIKE A SIMILAR DAY ON WEDNESDAY AS RIDGE SLOWLY SHIFTS EAST. BACK DOOR COLD FRONT SHOULD QUICKLY WASH OUT WITH DAYTIME HEATING...AND MORNING FOG AND STRATUS WILL GIVE WAY TO AT LEAST PARTIAL SUNSHINE. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE...LESS THAN TODAY. HIGHS IN THE MID 80S...EXCEPT ALONG THE COAST. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... THE UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY TRANSLATES EAST THROUGH THE END OF THE WEEK AND THEN OFFSHORE BY THE WEEKEND. INTERACTION WITH SHORT WAVE ENERGY IN THE NORTHERN BRANCH OF THE POLAR JET ACROSS EASTERN CANADA WILL AMPLIFY THE TROUGH ACROSS THE OH VALLEY AND MID ATLANTIC STATES. THIS AMPLIFICATION RESULTS IN TIMING ISSUES AMONGST THE GLOBAL MODELS...WITH THE OPERATIONAL 12Z GFS THE SLOWEST AT THE WESTERN END OF THE ENVELOPE. THE ECMWF AND GGEM ARE THE QUICKEST WITH SWINGING THE FRONT ACROSS THE COAST BY FRI MORNING. IN FACT...THE GFS CONTINUES TO BECOME MUCH SLOWER THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW CLOSES OFF APPROACHING THE MID ATLANTIC STATES...TAKING ON A NEGATIVE TILT MUCH CLOSER TO THE COAST. THIS WOULD RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. PREFERENCE AT THIS TIME WAS TO LEAN TOWARD THE FASTER MODEL CONSENSUS WITH PCPN SHUTTING DOWN FRI AFT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER. AS FOR THE SENSIBLE WEATHER...COLD FRONT APPROACHES FROM THE WEST THU...PASSING ACROSS THE REGION THU NIGHT INTO FRI. HIGH PW VALUES AND MODERATE INSTABILITY WILL LEAD TO THE DEVELOPMENT OF WIDESPREAD SHOWERS AND THUNDERSTORMS THAT WORK WEST TO EAST DURING THIS TIME. THE ISOLATED SEVERE THREAT APPEARS LOW AT THIS TIME WITH THE LOW-LEVEL JET DISPLACED EAST OF THE AREA AND MARGINAL DEEP LAYER SHEAR. UNIDIRECTIONAL WIND PROFILES SUPPORT SOME BOWING LINE SEGMENTS WITH GUSTY WINDS. WET-BULB ZERO VALUES ARE WARM...SUPPORTING ONLY SMALL HAIL. THE MAIN THREAT LOOKS TO BE THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY IF THE UPPER FLOW BACKS FURTHER WITH THE AMPLIFICATION OF THE UPPER TROF TO THE WEST. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. A DRIER NW FLOW SET UPS FRI NIGHT WITH STRONG COLD ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES BELOW SEASONABLE LEVELS. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... LITTLE CHANGE TO THE AVIATION FORECAST AS A NEARLY STATIONARY FRONT WILL REMAIN NORTH ACROSS THE LOWER HUDSON VALLEY WHILE FARTHER EAST THE FRONT WAS MOVING WESTWARD AS A COLD FRONT. THE FRONT WILL MAKE IT TO AROUND NEW YORK CITY BY MORNING BEFORE MOVING BACK NORTH DURING THE MORNING. STRATUS AND FOG HAS BEGUN TO MOVE IN FROM THE EAST AND WILL MOVE INTO THE NYC AREA TERMINALS FROM 08Z TO 10Z. CEILINGS AND VISIBILITIES BECOME IFR AND AS LOW AS VLIFR AT THE COASTAL TERMINALS ESPECIALLY AFTER 07Z. CONDITIONS IMPROVE EARLY WEDNESDAY MORNING...13Z TO 15Z. TIMING OF IMPROVEMENT AND CONDITIONS UNCERTAIN. WIND WILL BE LIGHT FROM THE SOUTH THROUGH THE NIGHT THEN INCREASE TO 10 TO 15 KT DURING WEDNESDAY. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AFTER 16Z MAINLY NORTH AND WEST OF THE NEW YORK TERMINALS. .OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .WEDNESDAY NIGHT...SCT SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG AND STRATUS. .THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG AND STRATUS. .SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR WITH NW WINDS INCREASING TO 20-30KT. .SUNDAY...VFR WITH NW WINDS 20-25KT. && .MARINE... DENSE FOG BEGINNING TO DEVELOP ACROSS THE EASTERN WATERS. THIS ADVECTION FOG IS EXPECTED TO EXPAND BACK WEST OVERNIGHT. SHALLOW BACK DOOR COLD FRONT SHOULD BRING SE-E WINDS OVERNIGHT TO THE ERN-MOST OCEAN WATERS...ALSO LONG ISLAND SOUND AND THE BAYS OF LONG ISLAND. OTHERWISE...S-SW SUB SCA WINDS SHOULD CONTINUE THROUGH WED NIGHT. SEAS SHOULD SLOWLY BUILD ON WED...BUT HAVE UNDERCUT WAVEWATCH TO PREVENT REACHING SCA CRITERIA UNTIL WEDNESDAY NIGHT. THINKING WITH STRONG INVERSION THAT WIND FORCING WAS OVERDONE IN THE WW3 FORECAST. A COLD FRONT WILL MOVE ACROSS THE AREA WATERS FRIDAY MORNING...WITH HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS COULD BE BELOW SCA LEVELS BY FRIDAY MORNING...WITH SEAS ON THE OCEAN REMAINING ABOVE SCA CRITERIA THROUGH MUCH SATURDAY MORNING. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS. && .HYDROLOGY... SLIGHT CHANCE FOR SOME SHOWERS/TSTMS TO ENTER THE AREA LATE TONIGHT INTO EARLY WED MORNING. SCT SHOWERS/TSTMS LATER WED WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMTS IN TSTMS. A MORE ORGANIZED EVENT LATE THU INTO FRI SHOULD PRODUCE AVERAGE BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD RESULT IN FLASH FLOODING. 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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ011-012. NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ079-081. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ330-340- 345-350-353. && $$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1232 AM EDT WED MAY 22 2013 .SYNOPSIS... A FRONTAL BOUNDARY WILL MOVE INTO THE AREA OVERNIGHT...THEN DISSIPATE WEDNESDAY MORNING. A COLD FRONT WILL THEN SLOWLY APPROACH FROM THE WEST...THEN PASS THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. CANADIAN HIGH PRESSURE WILL THEN BUILD IN FOR THE MEMORIAL DAY WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... HAVE UPDATED GRIDS TO REFLECT CURRENT OBSERVATION TRENDS. ADVECTION FOG/STRATUS EXPANDING INTO ERN-MOST LONG ISLAND SOUND AND NEARBY LAND AREAS. WILL CONTINUE WITH DENSE FOG ADVY FOR THE FORKS OF LONG ISLAND AND COASTAL SE CT...WITH PATCHY FOG ELSEWHERE. WATCHING LINE OF CONVECTION OVER CENTRAL NY STATE...WHICH THE RA AND HRRR SUGGEST COULD MAKE A RIGHT TURN TOWARD THE CWA OVERNIGHT INTO EARLY WED MORNING. CONVECTION APPEARS OUTFLOW-DOMINATED WHICH SUGGESTS EVENTUAL WEAKENING. HOWEVER...SINCE THAT OUTFLOW IS SOMEWHAT ALIGNED WITH THE BULK 0-3 KM SHEAR...SOME REDEVELOPMENT COULD OCCUR CLOSER TO THE HUDSON VALLEY AND INTERIOR SW CT LATE TONIGHT...SO HAVE CARRIED A SLIGHT CHANCE POP FOR ALL AREAS LATE TONIGHT INTO WED MORNING. BACK DOOR FRONT ADVANCING WWD INTO SOUTHERN CT AND EASTERN LONG ISLAND WILL LEAD TO A COOLER NIGHT THAN ORIGINALLY FORECAST...WITH LOWER 55-60. IT WILL HOWEVER REMAIN WARM AND MUGGY OVER THE HUDSON VALLEY...NYC METRO AND LONG ISLAND...WITH LOWS IN THE 60S. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... LOOKS LIKE A SIMILAR DAY ON WEDNESDAY AS RIDGE SLOWLY SHIFTS EAST. BACK DOOR COLD FRONT SHOULD QUICKLY WASH OUT WITH DAYTIME HEATING...AND MORNING FOG AND STRATUS WILL GIVE WAY TO AT LEAST PARTIAL SUNSHINE. CONVECTION SHOULD BE SCATTERED AT BEST WITH ONLY MARGINAL INSTABILITY IN PLACE...LESS THAN TODAY. HIGHS IN THE MID 80S...EXCEPT ALONG THE COAST. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... THE UPPER TROUGH OVER THE MID SECTION OF THE COUNTRY TRANSLATES EAST THROUGH THE END OF THE WEEK AND THEN OFFSHORE BY THE WEEKEND. INTERACTION WITH SHORT WAVE ENERGY IN THE NORTHERN BRANCH OF THE POLAR JET ACROSS EASTERN CANADA WILL AMPLIFY THE TROUGH ACROSS THE OH VALLEY AND MID ATLANTIC STATES. THIS AMPLIFICATION RESULTS IN TIMING ISSUES AMONGST THE GLOBAL MODELS...WITH THE OPERATIONAL 12Z GFS THE SLOWEST AT THE WESTERN END OF THE ENVELOPE. THE ECMWF AND GGEM ARE THE QUICKEST WITH SWINGING THE FRONT ACROSS THE COAST BY FRI MORNING. IN FACT...THE GFS CONTINUES TO BECOME MUCH SLOWER THAN ALL THE GUIDANCE FRI INTO SAT AS THE UPPER LOW CLOSES OFF APPROACHING THE MID ATLANTIC STATES...TAKING ON A NEGATIVE TILT MUCH CLOSER TO THE COAST. THIS WOULD RESULT IN A PROLONGED PERIOD OF POST-FRONTAL RAIN INTO SAT. PREFERENCE AT THIS TIME WAS TO LEAN TOWARD THE FASTER MODEL CONSENSUS WITH PCPN SHUTTING DOWN FRI AFT. SUBSEQUENT MODEL TRENDS WILL NEED TO BE CLOSELY MONITORED TO SEE IF THE FRONTAL SYSTEM SLOWS DOWN EVEN FURTHER. AS FOR THE SENSIBLE WEATHER...COLD FRONT APPROACHES FROM THE WEST THU...PASSING ACROSS THE REGION THU NIGHT INTO FRI. HIGH PW VALUES AND MODERATE INSTABILITY WILL LEAD TO THE DEVELOPMENT OF WIDESPREAD SHOWERS AND THUNDERSTORMS THAT WORK WEST TO EAST DURING THIS TIME. THE ISOLATED SEVERE THREAT APPEARS LOW AT THIS TIME WITH THE LOW-LEVEL JET DISPLACED EAST OF THE AREA AND MARGINAL DEEP LAYER SHEAR. UNIDIRECTIONAL WIND PROFILES SUPPORT SOME BOWING LINE SEGMENTS WITH GUSTY WINDS. WET-BULB ZERO VALUES ARE WARM...SUPPORTING ONLY SMALL HAIL. THE MAIN THREAT LOOKS TO BE THE POTENTIAL FOR HEAVY RAINFALL...ESPECIALLY IF THE UPPER FLOW BACKS FURTHER WITH THE AMPLIFICATION OF THE UPPER TROF TO THE WEST. AVERAGE BASIN RAINFALL SHOULD BE CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. A DRIER NW FLOW SET UPS FRI NIGHT WITH STRONG COLD ADVECTION. HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND INTO THE MID ATLANTIC STATES THROUGH EARLY NEXT WEEK WITH TEMPERATURES SEVERAL DEGREES BELOW SEASONABLE LEVELS. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... A NEARLY STATIONARY FRONT WILL REMAIN NORTH ACROSS THE LOWER HUDSON VALLEY WHILE FARTHER EAST THE FRONT WAS MOVING WESTWARD AS A COLD FRONT. THE FRONT WILL MAKE IT TO AROUND NEW YORK CITY BY MORNING BEFORE MOVING BACK NORTH DURING THE MORNING. STRATUS AND FOG WAS BEGINNING TO MOVE IN FROM THE EAST AND WILL MOVE INTO THE NYC AREA TERMINALS FROM 08Z TO 10Z. CEILINGS AND VISIBILITIES BECOME IFR AND AS LOW AS VLIFR AT THE COASTAL TERMINALS ESPECIALLY AFTER 07Z. CONDITIONS IMPROVE EARLY WEDNESDAY MORNING...13Z TO 15Z. TIMING OF IMPROVEMENT AND CONDITIONS UNCERTAIN. WIND WILL BE LIGHT FROM THE SOUTH THROUGH THE NIGHT THEN INCREASE TO 10 TO 15 KT DURING WEDNESDAY. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AFTER 16Z MAINLY NORTH AND WEST OF THE NEW YORK TERMINALS. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .WEDNESDAY NIGHT...SCT SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG AND STRATUS. .THURSDAY-FRIDAY...NUMEROUS SHRA AND TSTMS POSSIBLE. IFR POSSIBLE IN FOG AND STRATUS. .SATURDAY...RESIDUAL SHRA BEHIND A COLD FRONT WITH MVFR. BECOMING VFR WITH NW WINDS INCREASING TO 20-30KT. .SUNDAY...VFR WITH NW WINDS 20-25KT. && .MARINE... DENSE FOG BEGINNING TO DEVELOP ACROSS THE EASTERN WATERS. THIS ADVECTION FOG IS EXPECTED TO EXPAND BACK WEST OVERNIGHT. SHALLOW BACK DOOR COLD FRONT SHOULD BRING SE-E WINDS OVERNIGHT TO THE ERN-MOST OCEAN WATERS...ALSO LONG ISLAND SOUND AND THE BAYS OF LONG ISLAND. OTHERWISE...S-SW SUB SCA WINDS SHOULD CONTINUE THROUGH WED NIGHT. SEAS SHOULD SLOWLY BUILD ON WED...BUT HAVE UNDERCUT WAVEWATCH TO PREVENT REACHING SCA CRITERIA UNTIL WEDNESDAY NIGHT. THINKING WITH STRONG INVERSION THAT WIND FORCING WAS OVERDONE IN THE WW3 FORECAST. A COLD FRONT WILL MOVE ACROSS THE AREA WATERS FRIDAY MORNING...WITH HIGH PRESSURE BUILDING THROUGH THE WEEKEND. WINDS COULD BE BELOW SCA LEVELS BY FRIDAY MORNING...WITH SEAS ON THE OCEAN REMAINING ABOVE SCA CRITERIA THROUGH MUCH SATURDAY MORNING. UNDERCUT WAVEWATCH BY A FOOT DURING THIS TIME AS IT WAS SLOWER BRINGING THE FRONTAL SYSTEM ACROSS THE AREA. THERE IS THOUGH SOME UNCERTAINTY WITH THE SEAS DUE TO THE TIMING DIFFERENCES AMONGST THE MODELS. && .HYDROLOGY... SLIGHT CHANCE FOR SOME SHOWERS/TSTMS TO ENTER THE AREA LATE TONIGHT INTO EARLY WED MORNING. SCT SHOWERS/TSTMS LATER WED WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH THE BEST CHANCES NORTH/WEST OF NYC. TOTAL BASIN AVG QPF FOR WED-THU COULD BE 1/4 TO 1/2 INCH...WITH LOCALLY HIGHER AMTS IN TSTMS. A MORE ORGANIZED EVENT LATE THU INTO FRI SHOULD PRODUCE AVERAGE BASIN RAINFALL AMOUNTS CLOSE TO AN INCH...WITH LOCALIZED HIGHER AMOUNTS. THERE IS THE POTENTIAL FOR TRAINING OF THUNDERSTORMS WHICH COULD RESULT IN FLASH FLOODING. 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. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ011-012. NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ079-081. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ330-340- 345-350-353. && $$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1035 AM EDT WED MAY 22 2013 .DISCUSSION... LARGE RIDGE AXIS OVER THE W ATLC WILL COMBINE WITH A WEAK LOW LVL TROF CENTERED OFF THE FL BIG BEND TO GENERATE AN ACTIVE WX PATTERN ACRS CENTRAL FL. DEEP BUT LIGHT SRLY FLOW WILL DRAW DEEP MOISTURE UP FROM THE S...PWAT VALUES INCREASE FROM 1.5" AT KTBW/KXMR TO 1.8" AT KMFL. RAP ANALYSIS SHOWING H100-H70 MEAN RH VALUES AOA 70PCT ACRS THE ENTIRE PENINSULA. AIRMASS IS NOT EXPLOSIVELY UNSTABLE AS H50 TEMPS ARE HOLDING ARND -9C WITH MID LVL LAPSE RATES BTWN 5.5-6.0C/KM. HOWEVER...POSITION OF THE TROF AXIS WILL PLACE THE EAST CENTRAL PENINSULA ON ITS ASCENDING SIDE. ACTIVITY ALREADY DVLPG AREAWIDE WILL CONTINUE THRU THE DAY...ESP ALNG THE EAST COAST SEA BREEZE AS IT DVLPS AND DRIFTS INLAND. THE OFF HOUR MAV GUIDANCE CONTINUES TO INDICATE POPS BTWN 60-70PCT... CAN SEE NO REASON TO DISCOUNT THEM AS MOISTURE IS ALMOST UNIFORMLY DISTRIBUTED THRU THE COLUMN AND THERE ARE NO SIGNIFICANT INHIBITORS TO UPWARD VERTICAL MOTION. MAX TEMPS WITHIN A FEW DEGS OF CLIMO AVG...M/U80S AREAWIDE. MINOR CHANGES TO PRECIP DISTRIBUTION AND TIMING TO FOCUS HIGHER POPS OVER INTERIOR AND N CSTL ZONES. && .AVIATION... THRU 22/22Z...PREVAILING VFR ALL SITES...NMRS SHRAS/SCT TSRAS DVLPG AND MVG N/NE ARND 10KTS WILL PRODUCE TEMPO IFR VSBYS/CIGS. BTWN 22/22Z-23/01Z...CONVECTION DIMINISHING BCMG SCT MVFR SHRAS W OF KTIX-KOBE...CONTG THRU 23/03Z. AFT 23/03Z...VFR ALL SITES WITH LCL MVFR VSBYS IN BR. && .MARINE... NO HIGHLIGHTS...NO SIG CHANGES. ATLC RIDGE AXIS OVER THE W ATLC WILL GENERATE A LIGHT TO GENTLE S/SE BREEZE ACRS THE AREA...SEAS 2-3FT NEARSHORE AND 3-4FT OFFSHORE. NMRS SHRAS/ISOLD TSRAS OVER THE GULF STREAM DUE TO A MOIST AND UNSTABLE AIRMASS. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...KELLY LONG TERM/IMPACT WX...BRAGAW
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
937 AM EDT WED MAY 22 2013 .UPDATE 2...TROUGH OF LOW PRESSURE OVER THE FLORIDA PENINSULA WILL CONTINUE TO MOVE SLOWLY EAST INTO THE WESTERN ATLANTIC WATERS TODAY. THIS WILL ALLOW FOR A LITTLE BIT OF DRIER AIR TO WORK INTO THE AREA FROM THE GULF OF MEXICO. HOWEVER...THE EAST AND WEST COAST SEA BREEZES WILL DEVELOP TODAY AND PUSH INLAND. THE WEST COAST SEA BREEZE WILL PUSH ACROSS THE AREA TODAY WITH THE EAST COAST SEA BREEZE REMAINING NEAR THE EAST COAST METRO AREAS DUE TO THE SOUTH TO SOUTHWEST STEERING FLOW OVER THE AREA. SO THE SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS THIS MORNING SHOULD DISSIPATE BY NOON TIME WITH SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE LAND AREAS. SO WILL KEEP THE SCATTERED TO NUMEROUS POPS OVER SOUTH FLORIDA FOR THIS AFTERNOON. THERE COULD ALSO BE A FEW STRONG STORMS OVER THE INTERIOR AND EAST COAST METRO AREAS THIS AFTERNOON INTO EARLY THIS EVENING. THE PRIMARY IMPACTS FROM THE STRONG STORMS WILL BE GUSTY WINDS...HEAVY RAINFALL...AND SMALL HAIL. SO WILL CONTINUE TO MENTION THIS IN THE MORNING HWO PACKAGE. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. && .UPDATE...54/BNB .PREV DISCUSSION... /ISSUED 719 AM EDT WED MAY 22 2013/ AVIATION...SCATTERED SHOWERS WILL CONTINUE THIS MORNING ACROSS THE EASTERN PORTIONS OF THE PENINSULA WITH TERMINALS KMIA...KOPF AND KTMB POSSIBLY HAVING BRIEF PERIODS OF MVFR CEILINGS. THERE IS A LINGERING MID TO UPPER LEVEL TROUGH AND AVAILABLE TROPICAL MOISTURE THAT IS EXPECTED TO ENHANCE CHANCES OF CONVECTION TODAY WITH ALL TERMINALS ASSIGNED VCTS AT 15Z EXCEPT FOR TERMINAL KAPF ASSIGNED AT 16Z. FOR ALL TERMINALS BRIEF PERIODS OF IFR CONDITIONS MAY BE POSSIBLE WITH THE STRONGER THUNDERSTORMS BY THE EARLY AFTERNOON. && PREV DISCUSSION... /ISSUED 523 AM EDT WED MAY 22 2013/ UPDATE...SHOWERS HAVE RECENTLY INCREASED OVER THE ATLANTIC WITH MOVEMENT ONSHORE THE COAST. SOME ARE BECOMING HEAVY WITH EVEN A THUNDERSTORM IN FAR SOUTH MIAMI-DADE WITH A FEW LIGHTNING STRIKES DETECTED. GIVEN THE RADAR TRENDS AND HRRR DEPICTION, HAVE INCREASED WEATHER TO NUMEROUS FOR ALL OF THE EAST COAST AND INTERIOR THROUGH THIS AFTERNOON. /GREGORIA && PREV DISCUSSION... /ISSUED 356 AM EDT WED MAY 22 2013/ DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN THE HAZARDOUS WEATHER OUTLOOK. THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND. FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE OFFING. MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND. FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 86 72 87 73 / 60 40 30 20 FORT LAUDERDALE 86 74 88 76 / 60 40 30 20 MIAMI 87 74 89 76 / 60 40 30 20 NAPLES 86 71 86 72 / 30 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION
NWS MIAMI FL
719 AM EDT WED MAY 22 2013 .AVIATION...SCATTERED SHOWERS WILL CONTINUE THIS MORNING ACROSS THE EASTERN PORTIONS OF THE PENINSULA WITH TERMINALS KMIA...KOPF AND KTMB POSSIBLY HAVING BRIEF PERIODS OF MVFR CEILINGS. THERE IS A LINGERING MID TO UPPER LEVEL TROUGH AND AVAILABLE TROPICAL MOISTURE THAT IS EXPECTED TO ENHANCE CHANCES OF CONVECTION TODAY WITH ALL TERMINALS ASSIGNED VCTS AT 15Z EXCEPT FOR TERMINAL KAPF ASSIGNED AT 16Z. FOR ALL TERMINALS BRIEF PERIODS OF IFR CONDITIONS MAY BE POSSIBLE WITH THE STRONGER THUNDERSTORMS BY THE EARLY AFTERNOON. && .PREV DISCUSSION... /ISSUED 523 AM EDT WED MAY 22 2013/ UPDATE...SHOWERS HAVE RECENTLY INCREASED OVER THE ATLANTIC WITH MOVEMENT ONSHORE THE COAST. SOME ARE BECOMING HEAVY WITH EVEN A THUNDERSTORM IN FAR SOUTH MIAMI-DADE WITH A FEW LIGHTNING STRIKES DETECTED. GIVEN THE RADAR TRENDS AND HRRR DEPICTION, HAVE INCREASED WEATHER TO NUMEROUS FOR ALL OF THE EAST COAST AND INTERIOR THROUGH THIS AFTERNOON. /GREGORIA PREV DISCUSSION... /ISSUED 356 AM EDT WED MAY 22 2013/ DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN THE HAZARDOUS WEATHER OUTLOOK. THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND. FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE OFFING. MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND. FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 86 72 87 73 / 60 30 30 20 FORT LAUDERDALE 85 74 88 76 / 60 20 30 20 MIAMI 87 74 89 76 / 60 20 30 20 NAPLES 85 71 86 72 / 40 20 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION
NWS MIAMI FL
523 AM EDT WED MAY 22 2013 .UPDATE...SHOWERS HAVE RECENTLY INCREASED OVER THE ATLANTIC WITH MOVEMENT ONSHORE THE COAST. SOME ARE BECOMING HEAVY WITH EVEN A THUNDERSTORM IN FAR SOUTH MIAMI-DADE WITH A FEW LIGHTNING STRIKES DETECTED. GIVEN THE RADAR TRENDS AND HRRR DEPICTION, HAVE INCREASED WEATHER TO NUMEROUS FOR ALL OF THE EAST COAST AND INTERIOR THROUGH THIS AFTERNOON. /GREGORIA && .PREV DISCUSSION... /ISSUED 356 AM EDT WED MAY 22 2013/ DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN THE HAZARDOUS WEATHER OUTLOOK. THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND. FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE OFFING. MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND. FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 86 72 87 73 / 60 30 30 20 FORT LAUDERDALE 85 74 88 76 / 60 20 30 20 MIAMI 87 74 89 76 / 60 20 30 20 NAPLES 85 71 86 72 / 40 20 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MIAMI FL
356 AM EDT WED MAY 22 2013 .DISCUSSION...A MID-UPPER TROUGH JUST OFF THE ATLANTIC COAST WILL GET PICKED UP AND MERGED BY A LONG WAVE TROUGH MOVING ACROSS THE GREAT LAKES. MOISTURE AND INSTABILITY CONTINUES SUFFICIENT TODAY TO ALLOW FOR SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP. HRRR IS SHOWING NUMEROUS ACTIVITY THIS AFTERNOON. THE FOCUS OF TSTORMS LOOKS TO BE ACROSS THE INTERIOR AND TO THE WEST PALM BEACH METRO AREA. A FEW STRONG TSTORMS ARE POSSIBLE WITH LOCALLY HEAVY RAINS THIS AFTERNOON GIVEN RESIDUAL COLD AIR ALOFT AS WELL AS SOME UPPER LEVEL DIVERGENCE ESPECIALLY ACROSS PALM BEACH COUNTY. HOWEVER, MID LEVEL TEMPS WILL SLOWLY BE WARMING THROUGH THE DAY. STILL, WE WILL HIGHLIGHT A FEW STRONG TSTORMS IN THE HAZARDOUS WEATHER OUTLOOK. THE TREND THURSDAY AND INTO THE WEEKEND IS A DRYING ONE WITH LESS AND LESS SHOWER AND TSTORMS ACTIVITY EXPECTED. THIS IS THE RESULT OF THE LOCAL AREA BEING EAST OF A BUILDING RIDGE OVER THE GULF AND WEST OF THE DEPARTING TROUGH WHICH WILL PROMOTE SUBSIDENCE. THAT BEING SAID, THERE STILL LOOKS TO BE THE POTENTIAL FOR SCATTERED AFTERNOON TSTORMS ALONG THE ATLANTIC COAST ON THURSDAY, AND ISOLATED TSTORMS FRIDAY. THE TAIL END OF A COLD FRONT PUSHES INTO FLORIDA ON FRIDAY. THIS FRONT DISSIPATES AND A STRONG SURFACE HIGH BUILDS INTO THE EASTERN U.S. OVER THE WEEKEND. FRIDAY LOOKS HOT AHEAD OF THE DISSIPATING FRONT WITH LOWER 90S MOST LOCALES. THEN OVER THE WEEKEND IT TURNS BREEZY ON A NORTHEAST WIND AS THE STRONG HIGH MOVES INTO THE OHIO VALLEY WITH A TIGHTER PRESSURE GRADIENT LOCALLY. THE NORTHEAST WIND IS FORECAST TO LOWER DEWPOINTS INTO THE MID 60S THIS WEEKEND, POSSIBLY EVEN LOWER 60S MAKING IT FEEL NICE...ESPECIALLY ALONG THE ATLANTIC COAST WHERE TEMPS WILL BE SLIGHTLY COOLER THAN THE GULF COAST ALONG WITH A STRONGER WIND. FOR NEXT WEEK, MOISTURE WILL SLOWLY INCREASE AS WINDS TURN EAST TO SOUTHEAST, LEADING TO AN INCREASING CHANCE OF DAILY SHOWERS AND THUNDERSTORMS. HOWEVER, NO SIGNIFICANT WEATHER FEATURES ARE IN THE OFFING. && .MARINE...WINDS WILL BE ON THE DECREASE THIS MORNING THEN RATHER LIGHT WINDS WILL PREVAIL THROUGH FRIDAY BEFORE WINDS TURN NORTHEAST AND INCREASE OVER THE WEEKEND WITH A CORRESPONDING INCREASE IN SEAS, ESPECIALLY OVER THE ATLANTIC. SWAN IS GENERATING SEAS OF UP TO 5 FEET OVER THE ATLANTIC THIS WEEKEND. && .FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES REMAIN ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 86 72 87 73 / 60 30 30 20 FORT LAUDERDALE 85 74 88 76 / 50 20 30 20 MIAMI 87 74 89 76 / 50 20 30 20 NAPLES 85 71 86 72 / 40 20 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...57/GREGORIA AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
144 AM EDT WED MAY 22 2013 .AVIATION... FOR THE SHORT TERM...PASSING SHOWERS WILL LIKELY AFFECT ALL EAST COAST TERMINALS EXCEPT KPBI FOR THE NEXT FEW HOURS. LOW CONFIDENCE OF AN ISOLATED THUNDERSTORM OCCURRING IN THIS PERIOD WITH BRIEF PERIODS OF MVFR CEILINGS POSSIBLE WITH PASSING SHOWERS. BY LATE WEDNESDAY MORNING AND INTO THE AFTERNOON HOURS...THE COMBINATION OF THE WEST AND EAST COAST SEA BREEZES...A LINGERING UPPER LEVEL LOW AND AVAILABLE MOISTURE SHOULD RESULT IN VCTS ALL TERMINALS AROUND 15Z. 60 && .PREV DISCUSSION... /ISSUED 949 PM EDT TUE MAY 21 2013/ UPDATE... UPDATED PRODUCTS EARLIER TO CANCEL FLOOD WATCH BUT HAVE KEPT SCT POPS GOING THROUGH THE NIGHT. IT APPEARS THAT THE HEAVY RAIN THREAT IS OVER, BUT WITH THE UPPER LOW STILL IN THE VICINITY CANNOT RULE OUT A POSSIBLE STORM JUST ABOUT ANYWHERE AT ANY TIME. LOW LEVEL FLOW CONTINUES SOUTHEASTERLY SO THE GREATEST THREAT WILL BE THE SOUTHEAST COAST ESPECIALLY IF A LITTLE BIT OF CONVERGENCE CAN SET UP WITH LESSENING FLOW NEAR THE COAST. THE HRRR CYCLE SEEMS TO CHANGE EVERY TWO TO THREE HOURS BUT THE LATEST RUN IS SHOWING QUIET ACTIVITY THROUGH 06Z BUT THE EARLIER RUN HAD SHOWN A FLARE UP OF CONVECTION LATER TONIGHT ALTHOUGH NOT WIDESPREAD. KOB PREV DISCUSSION... /ISSUED 758 PM EDT TUE MAY 21 2013/ AVIATION... THE SHOWERS AND SHOULD COME TO AN END OVER SOUTH FLORIDA BY 03Z TONIGHT AND REMAIN DRY THROUGH 15Z ON WEDNESDAY. SO WILL KEEP VCSH IN THE ALL OF SOUTH FLORIDA TAF SITES UNTIL 03Z...BEFORE GOING DRY FOR REST OF TONIGHT. THE WINDS TONIGHT WILL ALSO REMAIN IN A EASTERLY DIRECTION AT 5 KNOTS OR LESS TONIGHT AT ALL OF THE TAF SITES. ON WEDNESDAY...THE WEATHER WILL REMAIN DRY UNTIL 15Z BEFORE SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP OVER SOUTH FLORIDA. SO WILL PUT IN A VCTS FOR ALL OF SOUTH FLORIDA TAF SITES AFTER 15Z ON WEDNESDAY. THE EASTERLY WINDS WILL ALSO INCREASE TO AROUND 10 KNOTS WEDNESDAY MORNING AT ALL OF THE TAF SITES AND REMAIN EASTERLY AT 10 KNOTS THROUGH WEDNESDAY AFTERNOON. THE ONLY EXCEPTION TO THIS IS AT KAPF TAF SITE...WHERE THE WIND DIRECTION WILL BECOME WESTERLY DUE TO THE WEST COAST SEA BREEZE PUSHING INLAND. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITION TONIGHT INTO WEDNESDAY AT ALL OF THE TAF SITES. AVIATION...54/BNB PREV DISCUSSION... /ISSUED 245 PM EDT TUE MAY 21 2013/ FLOOD WATCH IN EFFECT UNTIL 10 PM EDT THIS EVENING FOR EAST COAST METRO AREAS... SHORT TERM... THE EAST AND WEST COAST SEA BREEZES WERE DEVELOPING ALONG BOTH COASTS OF SOUTH FLORIDA EARLY THIS AFTERNOON. THESE SEA BREEZES WILL PUSH SLOWLY INLAND THROUGH THE REST OF THE AFTERNOON HOURS HELPING TO GENERATE SHOWERS AND THUNDERSTORMS OVER THE AREA. THE STORMS WILL BE SLOW MOVING THIS AFTERNOON INTO THIS EVENING...AS THE STEERING FLOW WILL BE LIGHT FROM THE SOUTH AHEAD OF A TROUGH OF LOW PRESSURE LOCATED OVER THE EASTERN GULF OF MEXICO. THE GPS-MET SATELLITE IMAGES WHERE SHOWING THE PWAT VALUES TO BE BETWEEN 1.6 TO 1.7 INCHES EARLY THIS AFTERNOON OVER SOUTH FLORIDA. THE AVERAGE PWAT VALUE FOR THIS TIME OF YEAR IS AROUND 1.35 INCHES FOR SOUTH FLORIDA. THIS WILL ALLOW FOR HEAVY RAINFALL OVER SOUTH FLORIDA THIS AFTERNOON INTO THIS EVENING. SO, WILL CONTINUE TO MENTION HEAVY RAINFALL IN THE FORECAST FOR SOUTH FLORIDA FOR THIS AFTERNOON INTO THIS EVENING. THE HEAVY RAINFALL FROM THE STORMS THIS AFTERNOON INTO THIS EVENING OVER THE EAST COAST METRO AREAS WILL ALLOW FOR SOME FLOODING TO OCCUR...AS THE GROUNDS ARE VERY SATURATED FROM THE HEAVY RAINFALL FROM THE STORMS YESTERDAY. THEREFORE...THE FLOOD WATCH WILL REMAIN IN PLACE OVER THE EAST COAST METRO AREAS THROUGH LATE THIS EVENING. THE MID TO UPPER LEVEL TROUGH OVER THE EASTERN GULF OF MEXICO WILL MOVE EAST TONIGHT THROUGH THE FLORIDA PENINSULA AS THE UPPER LEVEL LOW OVER NORTHERN FLORIDA MOVES EAST INTO THE WESTERN ATLANTIC WATERS. THIS WILL ALLOW FOR THE DEEPER MOISTURE OVER SOUTH FLORIDA TO MOVE EAST INTO THE WESTERN ATLANTIC WATERS ON WEDNESDAY WHICH WILL ALLOW FOR SOME DRIER AIR TO WORK INTO THE AREA FROM THE CENTRAL GULF OF MEXICO. THE DRIER AIR WILL STICK AROUND ON THURSDAY OVER SOUTH FLORIDA. HOWEVER...THERE WILL STILL BE ENOUGH MOISTURE OVER SOUTH FLORIDA EACH DAY TO ALLOW FOR SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE AREA ON WEDNESDAY AND THURSDAY ALONG THE SEA BREEZES WITH THE BEST COVERAGE OVER THE INTERIOR AREAS. LONG TERM... A COLD FRONT LOCATED OVER THE CENTRAL UNITED STATES IS FORECAST BY THE LONG RANGE MODELS TO MOVE SOUTHEAST AND THROUGH SOUTH FLORIDA EARLY THIS WEEKEND. HIGH PRESSURE SHOULD THEN BUILD INTO THE AREA FROM THE NORTH LATE THIS WEEKEND INTO EARLY NEXT WEEK. THIS WILL ALLOW FOR MUCH DRIER AIR TO WORK INTO THE AREA FROM THE NORTH FOR LATE THIS WEEKEND INTO EARLY NEXT WEEK. SO WILL KEEP A SLIGHT CHANCE OF POPS OVER SOUTH FLORIDA FOR THE EARLY PART OF THIS WEEKEND BEFORE GOING DRY FOR THE SECOND HALF OF THIS WEEKEND INTO EARLY NEXT WEEK. AVIATION... SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AND PUSH SLOWLY NORTH THROUGH THE AFTERNOON HOURS. SO KEPT VCTS FOR ALL TAF SITES THROUGH THE AFTERNOON. A FEW SHOWERS MAY MOVE NEAR THE EAST COAST TAF SITES OVERNIGHT. AN UPPER LEVEL TROUGH WILL SHIFT EAST TONIGHT INTO WEDNESDAY...PUSHING THE BEST DYNAMICS OVER THE ATLANTIC WATERS. SO THUNDERSTORM ACTIVITY IS EXPECTED TO START NEAR THE END OF THE TAF PERIOD ALONG THE SEA BREEZE BOUNDARIES. MARINE... THE WINDS WILL BE SOUTHERLY BELOW 10 KNOTS THROUGH LATE THIS WEEK...BEFORE INCREASING TO BREEZY CONDITIONS FROM THE NORTHEAST DIRECTION FOR THIS WEEKEND. THIS WILL ALLOW FOR THE SEAS TO REMAIN BELOW 6 FEET FOR BOTH THE ATLANTIC AND GULF WATERS OF SOUTH FLORIDA THROUGH LATE THIS WEEK INTO EARLY THIS WEEKEND...BEFORE INCREASING TO AROUND 6 FEET IN THE GULF STREAM WATERS OF THE ATLANTIC BY LATE THIS WEEKEND. FIRE WEATHER... THE RELATIVE HUMIDITY WILL REMAIN ABOVE THE 35 PERCENT CRITICAL VALUE OVER SOUTH FLORIDA THROUGH REST OF THIS WEEK. SO NO PROBLEMS ARE EXPECTED WITH THE FIRE WEATHER OVER SOUTH FLORIDA. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 86 74 88 73 / 50 40 30 30 FORT LAUDERDALE 86 77 88 76 / 50 30 30 20 MIAMI 87 76 89 75 / 50 30 30 20 NAPLES 87 71 88 71 / 40 20 20 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...57/DG AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
600 PM CDT WED MAY 22 2013 ...UPDATE TO AVIATION FOR 00Z TAFS... .SYNOPSIS... ISSUED AT 340 PM CDT WED MAY 22 2013 THE 12Z UPPER AIR ANALYSIS SHOWED THE REMAINS OF THE NORTHERN PLAINS CLOSED LOW WEAKENING OVER SOUTHERN MINNESOTA AS IT IS GETTING PHASED WITH A STRONG SHORTWAVE TROUGH OVER HUDSON`S BAY. A DEEP CLOSED LOW WAS OVER THE PACIFIC NORTHWEST. IN BETWEEN THESE FEATURES, WEAK UPPER LEVEL RIDGING EXTENDED FROM CENTRAL CANADA SOUTHWARD ALONG THE EASTERN SLOPES OF THE ROCKIES AND ADJACENT HIGH PLAINS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 340 PM CDT WED MAY 22 2013 THE UPPER LOW WILL CONTINUE TO FILL AS IT MOVES INTO THE GREAT LAKES ON THURSDAY. AS IT MOVES OUT, A SHORTWAVE TROUGH WILL ROTATE AROUND THE WEST PART OF THE UPPER LOW, WHICH WILL HELP PUSH A COLD FRONT SOUTH INTO THE CENTRAL HIGH PLAINS TONIGHT. A WEAK DISTURBANCE WAS EVIDENT IN THE WATER VAPOR IMAGERY MOVING OUT OF THE FOUR CORNERS REGION THIS AFTERNOON. THE MODELS ARE NOT PICKING UP ON THIS FEATURE VERY WELL. THEY DO SHOW SOME WARM AIR ADVECTION DEVELOPING AHEAD OF IT OVER WESTERN KANSAS TONIGHT ALONG WITH SOME VERY WEAK ELEVATED INSTABILITY ATOP THE COLD FRONT AND LOW LEVEL COLD ADVECTION THAT WILL BE MOVING INTO WESTERN KANSAS THIS EVENING. THE HRRR IS STARTING TO SHOW CONVECTION DEVELOPING OVER EASTERN COLORADO THIS EVENING WORKING INTO WESTERN KANSAS OVERNIGHT. LOW STRATUS IS ALSO EXPECTED TO DEVELOP BEHIND THE FRONT TONIGHT. ON THURSDAY, SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MOVE INTO CENTRAL KANSAS WHERE THE BEST, ALBEIT WEAK, ELEVATED INSTABILITY WILL BE. AREAS FARTHER WEST WILL BE CLOUDY TO MOSTLY CLOUDY BUT STABLE ALOFT. HIGH TEMPERATURES WILL STRUGGLE INTO THE LOW 70S IN MOST AREAS GIVEN THE CLOUD COVER. AREAS ALONG THE OKLAHOMA BORDER COULD REACH THE LOW/MID 70S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 348 PM CDT WED MAY 22 2013 LOW LEVEL MOISTURE WILL SURGE BACK TO THE NORTHWEST INTO THE SOUTHERN PLAINS BY LATE THURSDAY AS UPPER LEVEL TROUGHING DEVELOPS ACROSS THE WESTERN UNITED STATES. SURGE HIGH PRESSURE WILL SLIDE SOUTHEASTWARD INTO THE MIDWEST. A WARM ADVECTION PATTERN WILL STRENGTHEN THURSDAY NIGHT AND SOME ELEVATED THUNDERSTORM ACTIVITY IS POSSIBLE. THE UPPER LEVEL RIDGE AXIS BETWEEN THE WESTERN AND EASTERN UNITED STATES TROUGHS WILL BE OVER THE CENTRAL PLAINS BY FRIDAY. BUT SOME MID LEVEL FLOW COMING THROUGH THE RIDGE WILL ALLOW FOR LEE TROUGHING AND A SURGE OF MOISTURE FROM THE SOUTHERN PLAINS INTO KANSAS. WESTERN KANSAS WILL BE ON THE SOUTHERN EDGE OF THE WESTERLIES AND THE UPPER LEVEL WINDS WILL NOT BE THAT IMPRESSIVE. HOWEVER, WITH 2000-3000 J/KG CAPE AND STRONG DIRECTIONAL TURNING, A FEW SEVERE THUNDERSTORMS ARE POSSIBLE, PARTICULARLY IN FAR SOUTHWEST KANSAS. HIGH TEMPERATURES FRIDAY WILL RANGE FROM THE UPPER 70S NEAR HAYS TO THE UPPER 80S IN FAR SOUTHWEST KANSAS CLOSER TO THE LEE TROUGH. UPPER LEVEL TROUGHING WILL REMAIN ACROSS THE WESTERN UNITED STATES THROUGH MID NEXT WEEK, ALTHOUGH THERE IS SOME UNCERTAINTY IN HOW FAR EAST IT WILL PROGRESS. THE ECMWF IS LESS PROGRESSIVE THAN THE OTHER MODELS AND GENERALLY A LESS PROGRESSIVE SOLUTION IS THE BEST ONE. FOR SATURDAY INTO MONDAY, MODERATE TO HIGH SURFACE BASED CAPE WILL BE IN PLACE AHEAD OF A DRYLINE. A FEW THUNDERSTORMS WILL DEVELOP EACH DAY ALONG THE DRYLINE AND SLOWLY MOVE EASTWARD. THESE STORMS COULD BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. THE UPPER LEVEL WINDS ARE STILL NOT PROGGED TO BE THAT STRONG, SO TORNADIC STORMS ARE NOT EXPECTED, BUT CANNOT BE RULED OUT GIVEN THE STRONG INSTABILITY. TEMPERATURES WILL BE FAIRLY WARM THROUGH THE EXTENDED WITH LOWS IN THE 60S AND HIGHS IN THE 80S AND 90S SINCE KANSAS WILL BE IN THE WARM SECTOR. THE WARMEST HIGH TEMPERATURES OUGHT TO BE IN FAR WESTERN KANSAS BEHIND THE DRYLINE AND THE WARMEST LOWS SHOULD BE IN SOUTH CENTRAL AND CENTRAL KANSAS WHERE DEWPOINTS AND WINDS WILL BE HIGHEST. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 600 PM CDT WED MAY 22 2013 LIGHT AND VARIABLE WINDS WILL EVENTUALLY BECOME NE/E 10-20 KT THROUGH THE OVERNIGHT HOURS. THESE UPSLOPE WINDS WILL CONTINUE INTO EARLY AFTERNOON AS WELL. STRATUS IS EXPECTED TO DEVELOP LATE TONIGHT. VFR OR MVFR CIGS EXPECTED. ISOLATED THREAT OF TS LATE TONIGHT BUT WILL KEEP OUT OF KGCK TAF FOR NOW DUE TO ISOLATED NATURE. BETTER CHANCE FOR THUNDERSTORMS TOMORROW. && .PRELIMINARY POINT TEMPS/POPS... DDC 51 72 58 81 / 10 20 40 30 GCK 50 71 58 83 / 10 20 30 40 EHA 52 76 59 88 / 10 30 30 40 LBL 53 74 60 87 / 10 30 30 40 HYS 47 71 56 77 / 10 20 40 40 P28 54 73 59 78 / 10 30 30 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GERARD SHORT TERM...GERARD LONG TERM...FINCH AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
356 PM CDT WED MAY 22 2013 ...UPDATED FOR LONG TERM DISCUSSION... .SYNOPSIS... ISSUED AT 340 PM CDT WED MAY 22 2013 THE 12Z UPPER AIR ANALYSIS SHOWED THE REMAINS OF THE NORTHERN PLAINS CLOSED LOW WEAKENING OVER SOUTHERN MINNESOTA AS IT IS GETTING PHASED WITH A STRONG SHORTWAVE TROUGH OVER HUDSON`S BAY. A DEEP CLOSED LOW WAS OVER THE PACIFIC NORTHWEST. IN BETWEEN THESE FEATURES, WEAK UPPER LEVEL RIDGING EXTENDED FROM CENTRAL CANADA SOUTHWARD ALONG THE EASTERN SLOPES OF THE ROCKIES AND ADJACENT HIGH PLAINS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 340 PM CDT WED MAY 22 2013 THE UPPER LOW WILL CONTINUE TO FILL AS IT MOVES INTO THE GREAT LAKES ON THURSDAY. AS IT MOVES OUT, A SHORTWAVE TROUGH WILL ROTATE AROUND THE WEST PART OF THE UPPER LOW, WHICH WILL HELP PUSH A COLD FRONT SOUTH INTO THE CENTRAL HIGH PLAINS TONIGHT. A WEAK DISTURBANCE WAS EVIDENT IN THE WATER VAPOR IMAGERY MOVING OUT OF THE FOUR CORNERS REGION THIS AFTERNOON. THE MODELS ARE NOT PICKING UP ON THIS FEATURE VERY WELL. THEY DO SHOW SOME WARM AIR ADVECTION DEVELOPING AHEAD OF IT OVER WESTERN KANSAS TONIGHT ALONG WITH SOME VERY WEAK ELEVATED INSTABILITY ATOP THE COLD FRONT AND LOW LEVEL COLD ADVECTION THAT WILL BE MOVING INTO WESTERN KANSAS THIS EVENING. THE HRRR IS STARTING TO SHOW CONVECTION DEVELOPING OVER EASTERN COLORADO THIS EVENING WORKING INTO WESTERN KANSAS OVERNIGHT. LOW STRATUS IS ALSO EXPECTED TO DEVELOP BEHIND THE FRONT TONIGHT. ON THURSDAY, SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MOVE INTO CENTRAL KANSAS WHERE THE BEST, ALBEIT WEAK, ELEVATED INSTABILITY WILL BE. AREAS FARTHER WEST WILL BE CLOUDY TO MOSTLY CLOUDY BUT STABLE ALOFT. HIGH TEMPERATURES WILL STRUGGLE INTO THE LOW 70S IN MOST AREAS GIVEN THE CLOUD COVER. AREAS ALONG THE OKLAHOMA BORDER COULD REACH THE LOW/MID 70S. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 348 PM CDT WED MAY 22 2013 LOW LEVEL MOISTURE WILL SURGE BACK TO THE NORTHWEST INTO THE SOUTHERN PLAINS BY LATE THURSDAY AS UPPER LEVEL TROUGHING DEVELOPS ACROSS THE WESTERN UNITED STATES. SURGE HIGH PRESSURE WILL SLIDE SOUTHEASTWARD INTO THE MIDWEST. A WARM ADVECTION PATTERN WILL STRENGTHEN THURSDAY NIGHT AND SOME ELEVATED THUNDERSTORM ACTIVITY IS POSSIBLE. THE UPPER LEVEL RIDGE AXIS BETWEEN THE WESTERN AND EASTERN UNITED STATES TROUGHS WILL BE OVER THE CENTRAL PLAINS BY FRIDAY. BUT SOME MID LEVEL FLOW COMING THROUGH THE RIDGE WILL ALLOW FOR LEE TROUGHING AND A SURGE OF MOISTURE FROM THE SOUTHERN PLAINS INTO KANSAS. WESTERN KANSAS WILL BE ON THE SOUTHERN EDGE OF THE WESTERLIES AND THE UPPER LEVEL WINDS WILL NOT BE THAT IMPRESSIVE. HOWEVER, WITH 2000-3000 J/KG CAPE AND STRONG DIRECTIONAL TURNING, A FEW SEVERE THUNDERSTORMS ARE POSSIBLE, PARTICULARLY IN FAR SOUTHWEST KANSAS. HIGH TEMPERATURES FRIDAY WILL RANGE FROM THE UPPER 70S NEAR HAYS TO THE UPPER 80S IN FAR SOUTHWEST KANSAS CLOSER TO THE LEE TROUGH. UPPER LEVEL TROUGHING WILL REMAIN ACROSS THE WESTERN UNITED STATES THROUGH MID NEXT WEEK, ALTHOUGH THERE IS SOME UNCERTAINTY IN HOW FAR EAST IT WILL PROGRESS. THE ECMWF IS LESS PROGRESSIVE THAN THE OTHER MODELS AND GENERALLY A LESS PROGRESSIVE SOLUTION IS THE BEST ONE. FOR SATURDAY INTO MONDAY, MODERATE TO HIGH SURFACE BASED CAPE WILL BE IN PLACE AHEAD OF A DRYLINE. A FEW THUNDERSTORMS WILL DEVELOP EACH DAY ALONG THE DRYLINE AND SLOWLY MOVE EASTWARD. THESE STORMS COULD BE SEVERE WITH LARGE HAIL AND DAMAGING WINDS. THE UPPER LEVEL WINDS ARE STILL NOT PROGGED TO BE THAT STRONG, SO TORNADIC STORMS ARE NOT EXPECTED, BUT CANNOT BE RULED OUT GIVEN THE STRONG INSTABILITY. TEMPERATURES WILL BE FAIRLY WARM THROUGH THE EXTENDED WITH LOWS IN THE 60S AND HIGHS IN THE 80S AND 90S SINCE KANSAS WILL BE IN THE WARM SECTOR. THE WARMEST HIGH TEMPERATURES OUGHT TO BE IN FAR WESTERN KANSAS BEHIND THE DRYLINE AND THE WARMEST LOWS SHOULD BE IN SOUTH CENTRAL AND CENTRAL KANSAS WHERE DEWPOINTS AND WINDS WILL BE HIGHEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1237 PM CDT WED MAY 22 2013 VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS CAN BE EXPECTED THROUGH THE AFTERNOON HOURS. A COLD FRONT IS EXPECTED TO PUSH THROUGH WESTERN KANSAS TONIGHT. WINDS WILL SWITCH AROUND TO THE EAST TO NORTHEAST BEHIND THE FRONT AND COULD BECOME GUSTY TO AROUND 20-25 KNOTS AT TIMES. STRATUS IS EXPECTED TO DEVELOP LATER TONIGHT ESPECIALLY OVER SOUTHWEST KANSAS. HAVE INTRODUCED LOW MVFR CIGS TO GARDEN CITY AND DODGE CITY BY 10Z THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 51 72 58 81 / 10 20 40 30 GCK 50 71 58 83 / 10 20 30 40 EHA 52 76 59 88 / 10 30 30 40 LBL 53 74 60 87 / 10 30 30 40 HYS 47 71 56 77 / 10 20 40 40 P28 54 73 59 78 / 10 30 30 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GERARD SHORT TERM...GERARD LONG TERM...FINCH AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
343 PM CDT WED MAY 22 2013 ...UPDATED SYNOPSIS AND SHORT TERM DISCUSSION... .SYNOPSIS... ISSUED AT 340 PM CDT WED MAY 22 2013 THE 12Z UPPER AIR ANALYSIS SHOWED THE REMAINS OF THE NORTHERN PLAINS CLOSED LOW WEAKENING OVER SOUTHERN MINNESOTA AS IT IS GETTING PHASED WITH A STRONG SHORTWAVE TROUGH OVER HUDSON`S BAY. A DEEP CLOSED LOW WAS OVER THE PACIFIC NORTHWEST. IN BETWEEN THESE FEATURES, WEAK UPPER LEVEL RIDGING EXTENDED FROM CENTRAL CANADA SOUTHWARD ALONG THE EASTERN SLOPES OF THE ROCKIES AND ADJACENT HIGH PLAINS. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 340 PM CDT WED MAY 22 2013 THE UPPER LOW WILL CONTINUE TO FILL AS IT MOVES INTO THE GREAT LAKES ON THURSDAY. AS IT MOVES OUT, A SHORTWAVE TROUGH WILL ROTATE AROUND THE WEST PART OF THE UPPER LOW, WHICH WILL HELP PUSH A COLD FRONT SOUTH INTO THE CENTRAL HIGH PLAINS TONIGHT. A WEAK DISTURBANCE WAS EVIDENT IN THE WATER VAPOR IMAGERY MOVING OUT OF THE FOUR CORNERS REGION THIS AFTERNOON. THE MODELS ARE NOT PICKING UP ON THIS FEATURE VERY WELL. THEY DO SHOW SOME WARM AIR ADVECTION DEVELOPING AHEAD OF IT OVER WESTERN KANSAS TONIGHT ALONG WITH SOME VERY WEAK ELEVATED INSTABILITY ATOP THE COLD FRONT AND LOW LEVEL COLD ADVECTION THAT WILL BE MOVING INTO WESTERN KANSAS THIS EVENING. THE HRRR IS STARTING TO SHOW CONVECTION DEVELOPING OVER EASTERN COLORADO THIS EVENING WORKING INTO WESTERN KANSAS OVERNIGHT. LOW STRATUS IS ALSO EXPECTED TO DEVELOP BEHIND THE FRONT TONIGHT. ON THURSDAY, SMALL CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MOVE INTO CENTRAL KANSAS WHERE THE BEST, ALBEIT WEAK, ELEVATED INSTABILITY WILL BE. AREAS FARTHER WEST WILL BE CLOUDY TO MOSTLY CLOUDY BUT STABLE ALOFT. HIGH TEMPERATURES WILL STRUGGLE INTO THE LOW 70S IN MOST AREAS GIVEN THE CLOUD COVER. AREAS ALONG THE OKLAHOMA BORDER COULD REACH THE LOW/MID 70S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 415 AM CDT WED MAY 22 2013 MEDIUM RANGE MODELS INDICATE A WEAK UPPER LEVEL RIDGE OF HIGH PRESSURE MOVING EAST INTO THE CENTRAL PLAINS THURSDAY AS A STRONG CLOSED OFF LOW REMAINS ANCHORED ACROSS THE PACIFIC NORTHWEST. THIS WILL SET UP A MORE DIVERGENT FLOW ALOFT ACROSS THE WESTERN HIGH PLAINS AS A PREVAILING EASTERLY UPSLOPE FLOW CONTINUES TO SLOWLY ADVECT MOISTURE INTO THE REGION NEAR THE SURFACE. THIS WILL BRING THE POSSIBILITY FOR SHOWERS AND POTENTIALLY THUNDERSTORMS TO PORTIONS OF WESTERN KANSAS THURSDAY AFTERNOON AND EVENING AS AN UPPER LEVEL JET CORE LIFTS NORTHEAST OUT OF THE DESERT SOUTHWEST INTO THE TEXAS PANHANDLE AND SOUTHERN KANSAS. HOWEVER, NAM AND GFS MODEL SOUNDINGS SHOW A LACK OF SIGNIFICANT INSTABILITY, NOT TO MENTION A POSSIBLE CAPPING ISSUE THAT COULD LIMIT THE POTENTIAL FOR THUNDERSTORMS. STILL, UPSLOPE AND INCREASED LOW LEVEL CONVERGENCE DUE TO A FRONTAL BOUNDARY PROJECTED TO EXTEND FROM SOUTHEAST COLORADO INTO THE TEXAS PANHANDLE MAY SUPPORT RAIN SHOWER DEVELOPMENT FROM THE TEXAS PANHANDLE NORTHEAST INTO PORTIONS OF SOUTHWEST KANSAS THURSDAY WITH A SLIGHT CHANCE FOR AN EMBEDDED THUNDERSTORM OR TWO. THUNDERSTORM CHANCES INCREASE FRIDAY AS THE UPPER LEVEL RIDGE AXIS SHIFTS SLIGHTLY EASTWARD WHILE SURFACE TROUGHING DEVELOPS AND STRENGTHENS ACROSS EASTERN COLORADO HELPING TO DRAW THE FRONTAL BOUNDARY NORTHWARD ACROSS WESTERN KANSAS. THIS WILL RESULT IN INCREASING INSTABILITY ACROSS THE REGION BETTER SUPPORTING POTENTIAL THUNDERSTORM DEVELOPMENT ACROSS SOUTHWEST AND CENTRAL KANSAS. THE UPPER LEVEL PATTERN IS EXPECTED TO CHANGE VERY LITTLE THROUGHOUT THE REMAINDER OF THE WEEKEND BRINGING A CHANCE FOR THUNDERSTORMS TO CENTRAL AND PORTIONS OF WESTERN KANSAS EACH DAY THROUGH SUNDAY. BELOW NORMAL TEMPERATURES ARE EXPECTED THURSDAY AS SURFACE HIGH PRESSURE DROPS SOUTHEAST FROM THE NORTHERN PLAINS INTO THE UPPER MIDWEST. THIS WILL HELP USHER SLIGHTLY COOLER AIR SOUTHWESTWARD INTO THE WESTERN HIGH PLAINS WITH H85 TEMPERATURES JUST ABOVE 10C ACROSS CENTRAL KANSAS TO THE MID TO UPPER TEENS(C) IN FAR SOUTHWEST KANSAS. ALONG WITH EXPECTED INCREASING CLOUDS, LOOK FOR HIGHS ONLY UP INTO THE 70S(F) THURSDAY AFTERNOON WITH THE COOLEST TEMPERATURES IN CENTRAL KANSAS. A WARM FRONT IS PROJECTED TO LIFT NORTH ACROSS WESTERN KANSAS FRIDAY AS SURFACE TROUGHING STRENGTHENS ACROSS EASTERN COLORADO. EXPECT SLIGHTLY WARMER TEMPERATURES FRIDAY AFTERNOON WITH HIGHS UP INTO THE MID TO UPPER 70S(F) ACROSS CENTRAL KANSAS TO THE LOWER AND POSSIBLY THE MID 80S(F) IN EXTREME SOUTHWEST KANSAS. THE WARMING TREND CONTINUES THROUGH THE WEEKEND WITH WIDESPREAD 80S(F) TO NEAR 90F SATURDAY AND SUNDAY AS THE LOW LEVEL SOUTHERLY FLOW PERSISTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1237 PM CDT WED MAY 22 2013 VFR CONDITIONS WITH LIGHT AND VARIABLE WINDS CAN BE EXPECTED THROUGH THE AFTERNOON HOURS. A COLD FRONT IS EXPECTED TO PUSH THROUGH WESTERN KANSAS TONIGHT. WINDS WILL SWITCH AROUND TO THE EAST TO NORTHEAST BEHIND THE FRONT AND COULD BECOME GUSTY TO AROUND 20-25 KNOTS AT TIMES. STRATUS IS EXPECTED TO DEVELOP LATER TONIGHT ESPECIALLY OVER SOUTHWEST KANSAS. HAVE INTRODUCED LOW MVFR CIGS TO GARDEN CITY AND DODGE CITY BY 10Z THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 51 72 58 81 / 10 20 40 30 GCK 50 71 58 83 / 10 20 30 40 EHA 52 76 59 88 / 10 30 30 40 LBL 53 74 60 87 / 10 30 30 40 HYS 47 71 56 77 / 10 20 40 40 P28 54 73 59 78 / 10 30 30 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GERARD SHORT TERM...GERARD LONG TERM...JJOHNSON AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS TOPEKA KS
326 AM CDT WED MAY 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 307 AM CDT WED MAY 22 2013 NORTHWEST FLOW BEGINNING TO TAKE OVER THE LOCAL AREA AS THE SLOW-MOVING NORTHERN PLAINS SYSTEM INCHES EASTWARD. A WEAK POTENTIAL VORTICITY ANOMALY WAS ROTATING SOUTHEAST INTO NORTHEAST KANSAS IN RECENT HOURS WITH ONLY SOME HIGH CLOUDS RESULTING IN SOMEWHAT DRY MID LEVELS. PERIODIC LOWER CLOUDS ALSO MAKING THEIR WAY SOUTHEAST INTO KANSAS. LOW-MID LEVEL MOISTURE WILL BE ON THE INCREASE TODAY...THOUGH FORCING FOR PRECIPITATION WILL BE LACKING ON THE SOUTHWEST SIDE OF THE SYSTEM AND IN DEEP BUT WEAK ISENTROPIC DOWNGLIDE. THE INCREASED CLOUDS AND SOME COLD AIR ADVECTION ON NORTHWEST WINDS SHOULD KEEP TEMPS A BIT COOLER THAN TUESDAY. SOME CLEARING SHOULD TAKE PLACE TONIGHT AS RIDGING BEGINS TO DEVELOP THROUGH THE TROPOSPHERE WITH ENOUGH WIND TO KEEP FOG IN CHECK. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 307 AM CDT WED MAY 22 2013 THURS THRU SAT...COOL HIGH PRESSURE CONTINUES TO PUSH SOUTH AND EAST OF THE AREA WED NIGHT THROUGH THURSDAY...AND ANTICIPATE ANOTHER DAY OF BELOW NORMAL HIGHS IN THE UPPER 60S NORTH TO MID 70S SOUTH. FAR WESTERN AREAS MAY SEE A SLIGHT CHANCE FOR SOME LATE NIGHT POPS INTO FRIDAY MORNING. CHANCES FOR PRECIPITATION IN THE AREA START TO INCREASE ON FRIDAY AS FRONT ASSOCIATED WITH NORTHERN ROCKIES SHORTWAVE SENDS TRAILING PRECIP INTO THE HIGH PLAINS AND MAY DEVELOP PRECIP SOUTHWARD ALONG THE MID LEVEL FRONT ON THE HIGH PLAINS. HAVE SPREAD POPS WEST TO EAST THROUGH FRIDAY...CONTINUING INTO FRIDAY NIGHT AS LLJ VEERS NE OFF THE HIGH PLAINS AGAIN AND BRINGS A SLIGHTLY HIGHER CHANCE FOR RAIN IN THE OVERNIGHT HOURS. THIS WAVE PROPAGATES EAST SE THROUGH THE RIDGE AXIS OVER THE STATE AND AS PROGGED WOULD LINGER STORM CHANCES INTO SATURDAY AFTERNOON. DEPENDING ON WHERE BOUNDARIES ASSOCIATED WITH THAT SYSTEM REMAIN AS THE LLJ INCREASES AGAIN EARLY SUNDAY MORNING...WOULD EXPECT ANOTHER ROUND OF PRECIPITATION SOMEWHERE IN NE KS. SUN-TUES...PRECIP CHANCES REMAIN SOMEWHAT ERRATIC AND DIFFICULT TO TIME AS SMALL ROUNDS OF SW ENERGY ROTATE NE OUT OF THE SWRN TROF. MOISTURE AND INSTABILITY ARE IN PLACE TO RESPOND TO THESE WAVES...AS WELL AS NIGHTLY CYCLE OF THE LOW LEVEL JET. HAVE PRECIP THROUGHOUT THE PERIOD WITH HIGHER CHANCES IN THE OVERNIGHT HOURS AS A RESULT. AS WINDS COME BACK AROUND FROM THE SOUTH...TEMPERATURES SHOULD WARM BACK TOWARD THE LOWER 80S FOR THE EXTENDED PORTION OF THE FORECAST PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1136 PM CDT TUE MAY 21 2013 LATEST OBS SHOW SOME MVFR CIGS TO THE NORTH ACROSS NEB. MODELS CONTINUE TO SHOW THESE CIGS REMAINING JUST NORTH OF THE TERMINALS WITH THE 00Z OBJECTIVE MOS GUIDANCE KEEPING CONDITIONS VFR. THEREFORE WILL MAINTAIN PREV VFR FORECAST. THE RAP AND GFS SUGGEST SOME DECENT MIXING WITH THE POTENTIAL FOR SOME SFC WIND GUSTS THROUGH THE LATE MORNING AND AFTERNOON ALONG WITH A STRATOCU DECK FORMING ABOVE 3 KFT. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...67 AVIATION...WOLTERS
AREA FORECAST DISCUSSION...CORRECTED
NWS TOPEKA KS
1149 PM CDT TUE MAY 21 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 339 PM CDT TUE MAY 21 2013 UPPER LOW REMAINS ACROSS THE NORTHERN PLAINS WITH ENERGY ROTATING AROUND THE BASE MOVING INTO NORTH CENTRAL NEBRASKA. A STRONG SHORTWAVE WAS MOVING INTO WESTERN OKLAHOMA AT LATE AFTERNOON. MODELS STILL SHOWING BEST FORCING (Q-VECTOR CONVERGENCE AND VORTICITY ADVECTION) REMAINING TO THE SOUTH OF THE FORECAST AREA THIS EVENING. SHORT RANGE HIGH RESOLUTION MODELS BREAK OUT SOME CONVECTION IN FAR EAST CENTRAL KANSAS EARLY THIS EVENING AND WILL MAINTAIN SMALL PRECIPITATION CHANCES FOR PARTS OF ANDERSON COUNTY THIS EVENING. COLD ADVECTION ACROSS NORTHERN KANSAS WILL CONTINUE THROUGH THE NIGHT WITH TEMPERATURES FALLING INTO THE UPPER 40S IN NORTH CENTRAL KANSAS TO THE MID 50S IN EAST CENTRAL KANSAS. CLOUDS WILL BE ON THE DECREASE WEDNESDAY MORNING AND EXPECT SOME SCATTERED CUMULUS CLOUDS FOR MUCH OF THE AFTERNOON. COOL HIGH PRESSURE WILL BUILD INTO NORTHEAST KANSAS WEDNESDAY AS THE UPPER TROUGH MOVES INTO THE GREAT LAKES DURING THE DAY. TEMPERATURES WILL BE COOLEST ACROSS THE FAR NORTH WITH HIGHS IN THE 60S WITH LOWER 70S ACROSS THE SOUTH. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 339 PM CDT TUE MAY 21 2013 WED NIGHT THROUGH THU NIGHT...THE UPPER TROUGH IN THE UPPER MS VALLEY WILL SWING EASTWARD INTO THE GREAT LAKES AS THE HIGH PLAINS UPPER RIDGE SHIFTS EASTWARD INTO THE EASTERN PLAINS. THIS WILL ALLOW FOR THE DRY NORTH TO NORTHEASTERLY FLOW THROUGH 850MB TO PERSIST AND KEEP ANY SIGNIFICANT MOISTURE AND/OR INSTABILITY TO THE SOUTH OF THE COUNTY WARNING AREA UNTIL LATER THURSDAY NIGHT. THIS WHEN WEAK THETA E/MOISTURE ADVECTION BEGINS ACROSS THE FAR WEST AND SOUTHWESTERN PORTIONS OF THE CWA...SO WILL INTRODUCE A SLIGHT CHANCE FOR THUNDERSTORMS AT THAT TIME. SEASONABLY COOL LOW TEMPERATURES IN THE UPPER 40S AND LOWER 50S WEDNESDAY NIGHT WILL EDGE UP INTO THE LOW TO MIDDLE 50S THURSDAY NIGHT WHILE HIGHS ON THURSDAY TOP OUT IN THE LOW TO MIDDLE 70S. FRI THROUGH TUESDAY...THE RIDGING ALOFT WILL SLOWLY TRANSLATE EASTWARD INTO THE MO AND MS VALLEY AREAS OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL TRANSITION THE FLOW ALOFT TO A MORE WEST AND SOUTHWESTERLY DIRECTION. THIS WILL ALLOW FOR A LEE SIDE SFC TROUGH/LOW IN THE CENTRAL HIGH PLAINS TO REMAIN ANCHORED THROUGH THE PERIOD. AT THE SAME TIME...THE UPPER FLOW WILL LIKELY DIRECT A SERIES OF WEAK SHORTWAVE TROUGHS OUT OF THE MAIN UPPER TROUGH IN THE WESTERN CONUS OUT INTO THE CENTRAL PLAINS. MOISTURE RETURN WILL CONTINUE/REMAIN IN PLACE THROUGH THE PERIOD...SO THE PASSAGE ANY OF THE SHORTWAVE WILL HAVE THE POTENTIAL TO TRIGGER CONVECTION ACROSS THE AREA THROUGH THE PERIOD. THIS FAR OUT IT REMAINS VERY DIFFICULT TO PIN DOWN THE TIMING AND/OR AREAL EXTENT OF ANY CONVECTION AND MESOSCALE FEATURES SUCH AS OUTFLOW BOUNDARIES FROM POSSIBLE MCS`S EACH DAY WOULD ONLY COMPLICATE THE FCST. HAVE THEREFORE CONTINUED A BROAD AND GENERAL FCST ON THE PRECIP POTENTIAL WITH HIGHS GENERALLY IN THE 80S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1136 PM CDT TUE MAY 21 2013 LATEST OBS SHOW SOME MVFR CIGS TO THE NORTH ACROSS NEB. MODELS CONTINUE TO SHOW THESE CIGS REMAINING JUST NORTH OF THE TERMINALS WITH THE 00Z OBJECTIVE MOS GUIDANCE KEEPING CONDITIONS VFR. THEREFORE WILL MAINTAIN PREV VFR FORECAST. THE RAP AND GFS SUGGEST SOME DECENT MIXING WITH THE POTENTIAL FOR SOME SFC WIND GUSTS THROUGH THE LATE MORNING AND AFTERNOON ALONG WITH A STRATOCU DECK FORMING ABOVE 3 KFT. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...53 LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1136 PM CDT TUE MAY 21 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 339 PM CDT TUE MAY 21 2013 UPPER LOW REMAINS ACROSS THE NORTHERN PLAINS WITH ENERGY ROTATING AROUND THE BASE MOVING INTO NORTH CENTRAL NEBRASKA. A STRONG SHORTWAVE WAS MOVING INTO WESTERN OKLAHOMA AT LATE AFTERNOON. MODELS STILL SHOWING BEST FORCING (Q-VECTOR CONVERGENCE AND VORTICITY ADVECTION) REMAINING TO THE SOUTH OF THE FORECAST AREA THIS EVENING. SHORT RANGE HIGH RESOLUTION MODELS BREAK OUT SOME CONVECTION IN FAR EAST CENTRAL KANSAS EARLY THIS EVENING AND WILL MAINTAIN SMALL PRECIPITATION CHANCES FOR PARTS OF ANDERSON COUNTY THIS EVENING. COLD ADVECTION ACROSS NORTHERN KANSAS WILL CONTINUE THROUGH THE NIGHT WITH TEMPERATURES FALLING INTO THE UPPER 40S IN NORTH CENTRAL KANSAS TO THE MID 50S IN EAST CENTRAL KANSAS. CLOUDS WILL BE ON THE DECREASE WEDNESDAY MORNING AND EXPECT SOME SCATTERED CUMULUS CLOUDS FOR MUCH OF THE AFTERNOON. COOL HIGH PRESSURE WILL BUILD INTO NORTHEAST KANSAS WEDNESDAY AS THE UPPER TROUGH MOVES INTO THE GREAT LAKES DURING THE DAY. TEMPERATURES WILL BE COOLEST ACROSS THE FAR NORTH WITH HIGHS IN THE 60S WITH LOWER 70S ACROSS THE SOUTH. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 339 PM CDT TUE MAY 21 2013 WED NIGHT THROUGH THU NIGHT...THE UPPER TROUGH IN THE UPPER MS VALLEY WILL SWING EASTWARD INTO THE GREAT LAKES AS THE HIGH PLAINS UPPER RIDGE SHIFTS EASTWARD INTO THE EASTERN PLAINS. THIS WILL ALLOW FOR THE DRY NORTH TO NORTHEASTERLY FLOW THROUGH 850MB TO PERSIST AND KEEP ANY SIGNIFICANT MOISTURE AND/OR INSTABILITY TO THE SOUTH OF THE COUNTY WARNING AREA UNTIL LATER THURSDAY NIGHT. THIS WHEN WEAK THETA E/MOISTURE ADVECTION BEGINS ACROSS THE FAR WEST AND SOUTHWESTERN PORTIONS OF THE CWA...SO WILL INTRODUCE A SLIGHT CHANCE FOR THUNDERSTORMS AT THAT TIME. SEASONABLY COOL LOW TEMPERATURES IN THE UPPER 40S AND LOWER 50S WEDNESDAY NIGHT WILL EDGE UP INTO THE LOW TO MIDDLE 50S THURSDAY NIGHT WHILE HIGHS ON THURSDAY TOP OUT IN THE LOW TO MIDDLE 70S. FRI THROUGH TUESDAY...THE RIDGING ALOFT WILL SLOWLY TRANSLATE EASTWARD INTO THE MO AND MS VALLEY AREAS OVER THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL TRANSITION THE FLOW ALOFT TO A MORE WEST AND SOUTHWESTERLY DIRECTION. THIS WILL ALLOW FOR A LEE SIDE SFC TROUGH/LOW IN THE CENTRAL HIGH PLAINS TO REMAIN ANCHORED THROUGH THE PERIOD. AT THE SAME TIME...THE UPPER FLOW WILL LIKELY DIRECT A SERIES OF WEAK SHORTWAVE TROUGHS OUT OF THE MAIN UPPER TROUGH IN THE WESTERN CONUS OUT INTO THE CENTRAL PLAINS. MOISTURE RETURN WILL CONTINUE/REMAIN IN PLACE THROUGH THE PERIOD...SO THE PASSAGE ANY OF THE SHORTWAVE WILL HAVE THE POTENTIAL TO TRIGGER CONVECTION ACROSS THE AREA THROUGH THE PERIOD. THIS FAR OUT IT REMAINS VERY DIFFICULT TO PIN DOWN THE TIMING AND/OR AREAL EXTENT OF ANY CONVECTION AND MESOSCALE FEATURES SUCH AS OUTFLOW BOUNDARIES FROM POSSIBLE MCS`S EACH DAY WOULD ONLY COMPLICATE THE FCST. HAVE THEREFORE CONTINUED A BROAD AND GENERAL FCST ON THE PRECIP POTENTIAL WITH HIGHS GENERALLY IN THE 80S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1136 PM CDT TUE MAY 21 2013 LATEST OBS SHOW SOME MVFR CIGS TO THE NORTH ACROSS NEB. MODELS CONTINUE TO SHOW THESE CIGS REMAINING JUST NORTH OF THE TERMINALS WITH THE 00Z OBJECTIVE MOS GUIDANCE KEEPING CONDITIONS VFR. THEREFORE WILL MAINTAIN PREV IFR FORECAST. THE RAP AND GFS SUGGEST SOME DECENT MIXING WITH THE POTENTIAL FOR SOME SFC WIND GUSTS THROUGH THE LATE MORNING AND AFTERNOON ALONG WITH A STRATOCU DECK FORMING ABOVE 3 KFT. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...53 LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS GRAY ME
1023 PM EDT THU MAY 23 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY CROSS THE REGION TONIGHT WILL STALL OFF THE COAST ON FRIDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT SOUTH OF CAPE COD FRIDAY NIGHT AND SLOWLY MOVE NORTH THROUGH THE GULF OF MAINE THROUGH SUNDAY MORNING. LOW PRESSURE WILL CONTINUE NORTH THROUGH THE MARITIMES SUNDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST MONDAY AND WILL SHIFT OFFSHORE ON TUESDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST ON WEDNESDAY. && .NEAR TERM /THROUGH FRIDAY/... UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS. RADAR CONTS TO SHOW AREAS OF SHOWERS AND ISOLD TSTMS OVER THE NRN MTNS WHERE WE HAVE ISSUED AN AREAL FLOOD ADVISORY. OVER SRN NH...THE ECHOES CONT TO WEAKEN AS THEY HEAD NORTH...DESPITE A PRECIPITABLE WATER LEVEL AXIS OF 1.6" OVER THE REGION. LATEST HRRR RUN CONTS TO SHOW PCPN STREAMING IN FROM THE SOUTH OVERNIGHT...ALONG AND AHEAD OF APPROACHING COLD FRONT. CATEGORICAL POPS WILL REMAIN IN THE GRIDS OVERNIGHT WITH PATCHY/AREAS OF FOG. EXPECT AROUND AN INCH OR SO OF RAINFALL OVER THE COASTAL AREAS WHICH REMAINS WELL BELOW FLASH FLOOD GUIDANCE. PREV DISC... COLD FRONT APPROACHING FROM THE WEST WILL MAKE FOR A WET AND BREEZY NIGHT ACROSS THE REGION. SCATTERED SHOWERS AND SOME THUNDERSTORMS WILL GRADUALLY CHANGE TO A WIDESPREAD RAIN OVERNIGHT AS THE FRONT SLOWLY CROSSES THE AREA. EXPECT THUNDERSTORM ACTIVITY TO BE MAINLY CONFINED TO NEW HAMPSHIRE LATE THIS AFTERNOON AND THIS EVENING AS MARINE LAYER PERSISTS ACROSS MOST OF MAINE. CAN`T RULE OUT A RUMBLE OF THUNDER OVERNIGHT BUT SHOULD BE ISOLATED AND HAVE NOT INCLUDED THIS IN THE FORECAST AFTER THIS EVENING. EXPECT OVERNIGHT LOWS TO BE UNIFORM ACROSS THE REGION WITH MOST AREAS DIPPING INTO THE MID 50S TO NEAR 60. && .SHORT TERM /FRIDAY NIGHT/... FRONT WILL STALL JUST OFF THE COAST ON FRIDAY WITH RAIN CONTINUING THROUGH THE DAY ACROSS THE FORECAST AREA. NOT EXPECTING TEMPERATURES TO MOVE MUCH FROM OVERNIGHT LOWS WITH MOST LOCATIONS ONLY REACHING THE UPPER 50S TO LOWER 60S. RAIN CONTINUES FRIDAY NIGHT AS LOW PRESSURE TRACKS NORTH ALONG THE FRONT. FOCUS WILL TURN TO AREA RIVERS IN NORTHERN ZONES WHERE STORM TOTALS COULD WILL FALL IN THE THE 2 TO 4 INCH RANGE BY LATE ON SUNDAY. && .LONG TERM /SATURDAY THROUGH THURSDAY/... CUTOFF AND SFC LOW WILL DRIFT SLOWLY NE THRU THE WEEKEND CONTINUING PRCP ACROSS THE FCST AREA WITH THE POTENTIAL FOR HEAVY RAINFALL. MODELS SHOWING MAX QPF ACROSS THE N/MT ZONES TO WRN NH ZONES. GFS MUCH HIGHER ON QPF...WITH OTHER MODELS PREFERRED. USED HPC QPF FOR A COMPROMISE. CUTOFF AND SFC LOWS MOVE NE OF THE AREA MONDAY WITH IMPROVING WX...BUT STILL COOL AIR AND CYCLONIC FLOW ALOFT ALONG WITH FAIRLY AMPLE RH COULD PRODUCE SOME CLOUDS AND PSBL -SHRA EVEN ON MONDAY. FOR NOW WILL GO WITH SLGT CHC. AN UPR LVL AND SFC RIDGE BUILD IN TUESDAY FINALLY BRINGING DRY WX WITH WARMING TEMPS. AN UPR LVL SHORT WAVE TROF SLIDES E THRU THE UPR LVL RIDGE LATE WEDNESDAY AND WEDNESDAY NGT...BRINGING ISOLD TO SCT SHRA TO THE REGION WEDNESDAY NGT AND THURSDAY. GENERALLY USED BLEND OF GFS40/NAM, MET/MAV & HPC QPF FOR DAYS 4 AND 5 THEN A BLEND OF GFS40, GMOS, MEX/ECE FOR THE REST OF THE LONG TERM FCST. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... SHORT TERM...IFR/LIFR CEILINGS/VSBY TONIGHT THROUGH FRIDAY. LONG TERM /SATURDAY THROUGH TUESDAY/...IFR/LIFR SATURDAY THRU MUCH OF SUNDAY...IMPROVING TO VFR WITH PSBL MVFR ON MONDAY THEN VFR TUESDAY. && .MARINE... SHORT TERM...SCA IN EFFECT THROUGH FRIDAY TONIGHT. LONG TERM /SATURDAY THROUGH TUESDAY/...NE WINDS AHEAD OF APPROACHING LOW AND SEAS LIKELY AT SCA LEVELS SATURDAY AND MAY NEED TO EXTEND THE SCA THRU THE DAY. WINDS LET UP AND BACK TO THE NW SLOWLY SATURDAY NGT THRU MONDAY...LIKELY DROPPING BELOW SCA LEVELS BY LATE SATURDAY NGT OR EARLY SUNDAY. SEAS WILL BE SLOWER TO DROP OFF. HIGH PRES PROVIDES RELATIVELY CALMER WINDS AND SEAS ON TUESDAY. && .FIRE WEATHER... NO PROBLEMS NOTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ150>154. && $$
AREA FORECAST DISCUSSION
NWS GRAY ME
854 PM EDT THU MAY 23 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY CROSS THE REGION TONIGHT WILL STALL OFF THE COAST ON FRIDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT SOUTH OF CAPE COD FRIDAY NIGHT AND SLOWLY MOVE NORTH THROUGH THE GULF OF MAINE THROUGH SUNDAY MORNING. LOW PRESSURE WILL CONTINUE NORTH THROUGH THE MARITIMES SUNDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST MONDAY AND WILL SHIFT OFFSHORE ON TUESDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST ON WEDNESDAY. && .NEAR TERM /THROUGH FRIDAY/... UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS. RADAR CONTS TO SHOW AREAS OF SHOWERS AND ISOLD TSTMS OVER THE NRN MTNS WHERE WE HAVE ISSUED AN AREAL FLOOD ADVISORY. OVER SRN NH...THE ECHOES CONT TO WEAKEN AS THEY HEAD NORTH...DESPITE A PRECIPITABLE WATER LEVEL AXIS OF 1.6" OVER THE REGION. LATEST HRRR RUN CONTS TO SHOW PCPN STREAMING IN FROM THE SOUTH OVERNIGHT...ALONG AND AHEAD OF APPROACHING COLD FRONT. CATEGORICAL POPS WILL REMAIN IN THE GRIDS OVERNIGHT WITH PATCHY/AREAS OF FOG. PREV DISC... COLD FRONT APPROACHING FROM THE WEST WILL MAKE FOR A WET AND BREEZY NIGHT ACROSS THE REGION. SCATTERED SHOWERS AND SOME THUNDERSTORMS WILL GRADUALLY CHANGE TO A WIDESPREAD RAIN OVERNIGHT AS THE FRONT SLOWLY CROSSES THE AREA. EXPECT THUNDERSTORM ACTIVITY TO BE MAINLY CONFINED TO NEW HAMPSHIRE LATE THIS AFTERNOON AND THIS EVENING AS MARINE LAYER PERSISTS ACROSS MOST OF MAINE. CAN`T RULE OUT A RUMBLE OF THUNDER OVERNIGHT BUT SHOULD BE ISOLATED AND HAVE NOT INCLUDED THIS IN THE FORECAST AFTER THIS EVENING. EXPECT OVERNIGHT LOWS TO BE UNIFORM ACROSS THE REGION WITH MOST AREAS DIPPING INTO THE MID 50S TO NEAR 60. && .SHORT TERM /FRIDAY NIGHT/... FRONT WILL STALL JUST OFF THE COAST ON FRIDAY WITH RAIN CONTINUING THROUGH THE DAY ACROSS THE FORECAST AREA. NOT EXPECTING TEMPERATURES TO MOVE MUCH FROM OVERNIGHT LOWS WITH MOST LOCATIONS ONLY REACHING THE UPPER 50S TO LOWER 60S. RAIN CONTINUES FRIDAY NIGHT AS LOW PRESSURE TRACKS NORTH ALONG THE FRONT. FOCUS WILL TURN TO AREA RIVERS IN NORTHERN ZONES WHERE STORM TOTALS COULD WILL FALL IN THE THE 2 TO 4 INCH RANGE BY LATE ON SUNDAY. && .LONG TERM /SATURDAY THROUGH THURSDAY/... CUTOFF AND SFC LOW WILL DRIFT SLOWLY NE THRU THE WEEKEND CONTINUING PRCP ACROSS THE FCST AREA WITH THE POTENTIAL FOR HEAVY RAINFALL. MODELS SHOWING MAX QPF ACROSS THE N/MT ZONES TO WRN NH ZONES. GFS MUCH HIGHER ON QPF...WITH OTHER MODELS PREFERRED. USED HPC QPF FOR A COMPROMISE. CUTOFF AND SFC LOWS MOVE NE OF THE AREA MONDAY WITH IMPROVING WX...BUT STILL COOL AIR AND CYCLONIC FLOW ALOFT ALONG WITH FAIRLY AMPLE RH COULD PRODUCE SOME CLOUDS AND PSBL -SHRA EVEN ON MONDAY. FOR NOW WILL GO WITH SLGT CHC. AN UPR LVL AND SFC RIDGE BUILD IN TUESDAY FINALLY BRINGING DRY WX WITH WARMING TEMPS. AN UPR LVL SHORT WAVE TROF SLIDES E THRU THE UPR LVL RIDGE LATE WEDNESDAY AND WEDNESDAY NGT...BRINGING ISOLD TO SCT SHRA TO THE REGION WEDNESDAY NGT AND THURSDAY. GENERALLY USED BLEND OF GFS40/NAM, MET/MAV & HPC QPF FOR DAYS 4 AND 5 THEN A BLEND OF GFS40, GMOS, MEX/ECE FOR THE REST OF THE LONG TERM FCST. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... SHORT TERM...IFR/LIFR CEILINGS/VSBY TONIGHT THROUGH FRIDAY. LONG TERM /SATURDAY THROUGH TUESDAY/...IFR/LIFR SATURDAY THRU MUCH OF SUNDAY...IMPROVING TO VFR WITH PSBL MVFR ON MONDAY THEN VFR TUESDAY. && .MARINE... SHORT TERM...SCA IN EFFECT THROUGH FRIDAY TONIGHT. LONG TERM /SATURDAY THROUGH TUESDAY/...NE WINDS AHEAD OF APPROACHING LOW AND SEAS LIKELY AT SCA LEVELS SATURDAY AND MAY NEED TO EXTEND THE SCA THRU THE DAY. WINDS LET UP AND BACK TO THE NW SLOWLY SATURDAY NGT THRU MONDAY...LIKELY DROPPING BELOW SCA LEVELS BY LATE SATURDAY NGT OR EARLY SUNDAY. SEAS WILL BE SLOWER TO DROP OFF. HIGH PRES PROVIDES RELATIVELY CALMER WINDS AND SEAS ON TUESDAY. && .FIRE WEATHER... NO PROBLEMS NOTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ150>154. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1009 AM EDT WED MAY 22 2013 .SYNOPSIS... A WARM FRONT WILL SLOWLY PROGRESS NORTH ACROSS THE REGION TODAY AND TONIGHT. LOW PRESSURE WILL LIFT TO OUR WEST ON THURSDAY THEN GRADUALLY PUSH A FRONT ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... 10 AM UPDATE...12Z KCAR RAOB SHOWS DEEP LAYER MOISTURE PROFILE THIS MORNING. VISIBLE IMAGERY ALSO SHOWS EXTENSIVE LOW CLOUD ACROSS THE FA. EXPECT CLOUDY SKIES ACROSS THE REGION TODAY. CURRENT RADAR IMAGERY DOES SHOW THE LAST OF THE STEADIER SHOWERS EXITING THE INTERNATIONAL BORDER INTO NEW BRUNSWICK. MADE ADJUSTMENTS TO POPS FOR TODAY UTILIZING THE RUC13 WHICH WAS DOING A FAIRLY GOOD JOB AS OF EARLY THIS MORNING. THUS...ONLY EXPECTING SCATTERED SHOWERS THE BALANCE OF THE DAY. OTHERWISE...ADJUSTED CURRENT HOURLY TEMPS AND INTERPOLATED TO EXPECTED MAX TEMPS. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA TONIGHT AS THE LOW FROM THE GREAT LAKES TRACKS TOWARD WESTERN NEW ENGLAND. SOME SHOWERS WILL OCCUR ALONG THE FRONT MAINLY ACROSS THE FAR NORTH. AN EMBEDDED RUMBLE OF THUNDER CAN`T BE RULED OUT. HUMID AIR WILL LIKELY RESULT IN SOME FOG IN MANY AREAS WEDNESDAY NIGHT. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AN ACTIVE AND UNSETTLED PATTERN WILL CONTINUE TO UNFOLD... LOW PRESSURE AND AN ASSOCIATED FRONTAL BOUNDARY LIFT NORTH EARLY THURSDAY WITH THE AREA BREAKING INTO A WARMER AND MORE HUMID AIR MASS. NOT EXPECTING MUCH IN THE WAY OF PRECIP IN THE MORNING HOWEVER IN THE AFTERNOON EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP OVER NW PORTIONS OF THE CWA ALONG AND AHEAD OF THE FRONT AS IT BEGINS TO COLLAPSE BACK TO THE SOUTH AND EAST. MODELS DEPICT CAPE VALUES OVER NW AREAS GENERALLY AROUND 500 TO 1000 J/KG BUT THERE IS CONCERN AS SHEAR VALUES LOOK TO BE QUITE STRONG, IN EXCESS OF 40 KNOTS FROM 0-6 KM, WHICH COULD RESULT IN ORGANIZED STRONGER STORMS DEVELOPING. PWAT VALUES NEAR 1.50 INCHES ALONG A FAIRLY DEEP WARM CLOUD LAYER AND SLOW STORM MOTION VECTORS SUGGEST HEAVY RAINFALL WILL BE THE BIGGEST THREAT BUT STRONG WINDS WILL ALSO BE POSSIBLE. HAVE ADDED ENHANCED WORDING MENTIONING HEAVY RAINFALL IN THE GRIDS WITH AGAIN, THE BIGGEST CONCERN LOOKING TO BE OVER ROUGHLY THE NORTHWESTERN THIRD OF THE CWA. SHOWERS/STORMS WILL CONTINUE TO SHIFT SOUTH AND EAST WITH THE FRONT THURSDAY NIGHT WHILE GENERALLY WEAKENING WITH TIME. GUIDANCE CONTINUES TO DEPICT THIS FRONT GETTING HUNG UP AS IT NEARS THE COAST HEADING INTO FRIDAY. THIS WILL KEEP PERIODS OF RAIN AND SHOWERS GOING RIGHT THROUGH FRIDAY WITH THE HEAVIEST AND STEADIEST PRECIPITATION SHIFTING TO SOUTHERN AND EASTERN AREAS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... THE GFS AND ECMWF HAVE COME INTO LINE BOTH DEPICTING LOW PRESSURE DEVELOPING ALONG THE STALLED FRONT AND PUSHING NORTH FRIDAY NIGHT INTO SATURDAY. THIS WILL RESULT IN CONTINUING RAINFALL THROUGH SATURDAY WITH ADDITIONAL AMOUNTS OF A HALF INCH TO AN INCH POSSIBLE BY LATE SATURDAY. WITH THE LOW LOOKING TO TRACK EAST OF THE AREA THIS WILL KEEP THE AREA ON THE COOL SIDE OF THE SYSTEM WITH NORTHERLY WINDS AND TEMPERATURES STRUGGLING TO MAKE IT OUT OF THE UPPER 40S AND LOW 50S FOR SATURDAY. THE PICTURE BECOMES EVEN MORE COMPLEX FOR SATURDAY NIGHT AS COLD AIR CONTINUES TO BE DRAWN SOUTH. THIS COULD POTENTIALLY RESULT IN RAIN CHANGING TO SOME WET SNOW OVER HIGHER ELEVATIONS SATURDAY BEFORE PRECIPITATION WINDS DOWN TO SHOWERS HEADING INTO SUNDAY. TEMPERATURES REMAIN VERY COOL FOR SUNDAY...ONLY REACHING THE LOW TO MID 50S AT BEST. EXPECT SLOW IMPROVEMENT HEADING INTO EARLY NEXT WEEK. THE LINGERING UPPER TROUGH WILL RESULT IN PERSISTING CLOUDS, COOL TEMPERATURES, AND THE CHANCE OF SHOWERS MONDAY WITH WARMER DRIER WEATHER EXPECTED BY TUESDAY. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: IFR CONDITIONS ARE EXPECTED IN LOW CLOUDS AND AREAS OF FOG TODAY AND TONIGHT ALTHOUGH CONDITIONS MAY BRIEFLY IMPROVE TO MVFR AT TIMES ACROSS THE NORTH DURING THE MIDDAY TODAY. SHORT TERM: EXPECT MVFR/IFR PERSISTING THURSDAY IN THE SOUTH DUE TO MARINE FOG AND STRATUS. NORTHERN SITES SHOULD SEE SOME BRIEF IMPROVEMENT DURING THE DAY BEFORE SHOWERS AND STORMS BRING A RETURN TO MVFR AND EVENTUALLY IFR BY LATE DAY. EXPECT PREDOMINATELY MVFR AND IFR CONDITIONS REGION WIDE THURSDAY NIGHT THROUGH SATURDAY DUE TO CONTINUING PERIODS OF RAIN AND SHOWERS. SOME IMPROVEMENT WILL BE POSSIBLE SUNDAY AS STEADIER PRECIPITATION WINDS DOWN. && .MARINE... NEAR TERM: WINDS AND SEAS WILL BE BELOW SCA TODAY AND TONIGHT. HUMID AIR MOVING IN OVER THE COLDER WATERS WILL LIKELY RESULT IN AREAS OF FOG THROUGH TONIGHT. SHORT TERM: WINDS/SEAS BUILD THURSDAY WITH SCA CONDITIONS EXPECTED BY THE AFTERNOON CONTINUING THROUGH FRIDAY MORNING. ALSO EXPECT AREAS OF FOG DURING THIS PERIOD REDUCING VISIBILITIES ALONG WITH PERIODS OF RAIN AND SHOWERS. WINDS/SEAS MAY BRIEFLY DIMINISH LATE FRIDAY BEFORE INCREASING ONCE AGAIN SATURDAY AS LOW PRESSURE MOVES NORTH. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON THURSDAY TO NOON EDT FRIDAY FOR ANZ050>052. && $$ NEAR TERM...BLOOMER/DUDA SHORT TERM...FITZSIMMONS LONG TERM...FITZSIMMONS AVIATION...BLOOMER/DUDA/FITZSIMMONS MARINE...BLOOMER/DUDA/FITZSIMMONS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
656 AM EDT WED MAY 22 2013 .SYNOPSIS... A WARM FRONT WILL REMAIN STALLED ACROSS NEW HAMPSHIRE AND MAINE TODAY...LIFTING NORTH OF THE REGION TONIGHT. A COLD FRONT WILL SLOWLY APPROACH FROM THE NORTHWEST THURSDAY PUSH OFFSHORE FRIDAY. LOW PRESSURE WILL DEVELOP ALONG THE FRONT SOUTH OF NEW ENGLAND FRIDAY NIGHT AND STRENGTHEN IN THE GULF OF MAINE ON SATURDAY, MOVING INTO THE CANADIAN MARITIMES ON SUNDAY, WITH COOLER THAN NORMAL TEMPERATURES EXPECTED FRIDAY THROUGH SUNDAY. ON MEMORIAL DAY AND TUESDAY HIGH PRESSURE WILL NUDGE THE LOW NORTHWARD WITH SEASONABLY WARM TEMPERATURES RETURNING TO NORTHERN NEW ENGLAND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... .UPDATE... NOT MUCH TO CHANGE FOR THIS UPDATE AS POPS ARE ON TRACK. AREA OF RAIN NOW MOVING INTO EASTERN MAINE AND OFFSHORE. HRRR HAS HAD A GOOD HANDLE ON THE EVOLUTION OF THIS RAIN EVENT. WE SHOULD HAVE A BREAK THROUGH THE MORNING BEFORE RAIN RETURNS THIS AFTERNOON. && PREVIOUS DISCUSSION... LIGHT TO MODERATE RAIN IS NOW MOVING OVER NORTHERN NEW ENGLAND WITH A RAIN FREE AREA IMMEDIATELY BEHIND IT. FARTHER SOUTH CONVECTION IS HEAVIER AND STILL MOVING ACROSS PORTSMOUTH WITH MORE TO THE SOUTH AND WEST. WHEN THE RAIN DOES SUBSIDE PATCHY DENSE FOG MAY FORM LATER THIS MORNING. MOST THUNDER IS TO OUR SOUTH HOWEVER HAVE KEPT ISOLATED STRIKES IN THE FORECAST THIS MORNING. A WARM FRONT IS THE FOCUS OF THE HEAVIER PRECIPITATION AND STRETCHES THROUGH SOUTHERN NY STATE AND OVER LONG ISLAND SOUND. MOST OF THE PRECIPITATION WITH THIS BATCH WILL EXIT BY LATE MORNING. WE WILL ONLY SEE A FEW HOURS MOSTLY FREE OF PRECIPITATION AS THE WARM FRONT LIFTS NORTH AND LOW PRESSURE OVER THE GREAT LAKES MOVES NORTHEAST ALONG IT. IN ADDITION DIURNAL HEATING AND MUCAPES AOA 1000 J/KG THIS AFTERNOON WILL TRIGGER THUNDERSTORMS. THAT SAID...SEVERE WEATHER IS NOT EXPECTED. TEMPERATURES TODAY WILL DEPEND ON THE EASTWARD PROGRESSION OF THE WARM FRONT. READINGS WILL RANGE FROM THE UPPER 50S NEAR JACKMAN AND WATERVILLE TO 70S OVER MUCH OF NH AND FAR WESTERN MAINE. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... RAIN CONTINUES TONIGHT INTO THE OVERNIGHT HOURS. THE WARM FRONT WILL LIFT INTO CANADA BY TOMORROW AFTERNOON PLACING THE ENTIRETY OF NH AND WESTERN MAINE IN THE WARM SECTOR. A NNE TO SSW ORIENTED COLD FRONT WILL ARRIVE FROM THE WEST LATE IN THE DAY THURSDAY HELPING TO GENERATE MODERATE RAIN AND ADDITIONAL THUNDERSTORMS. AFTER WARM OVERNIGHT LOWS...ALMOST THE ENTIRE REGION SHOULD WARM INTO THE 70S THURSDAY. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE SURFACE COLD FRONT APPROACHES FROM THE WEST THURSDAY NIGHT BUT WILL BE SLOWED BY A STRENGTHENING SURFACE LOW FORECAST TO RIDE NORTH UP THE ATLANTIC SEABOARD THURSDAY NIGHT INTO FRIDAY AND SATURDAY. EXPECTEDLY, THE FORECAST MODELS ARE BICKERING ABOUT THE STRENGTH OF THIS LOW, WHICH WILL ULTIMATELY DETERMINE HOW RAPIDLY THE WET WEATHER WILL EXIT EASTERN NEW ENGLAND. THE GFS CONTINUES TO BE BY FAR THE MOST AGGRESSIVE WITH THIS LOW -- CLOSING OFF A 1001 HPA LOW IN THE BAY OF FUNDY SATURDAY NIGHT. WPC HAS CONTINUED TO FAVOR THE CONSISTENT AND WEAKER ECMWF SOLUTION, AND WE`VE FOLLOWED THAT THINKING AS WELL HERE. THIS TRANSLATES TO DRYING OUT ON SATURDAY INTO SUNDAY, WITH DRY WEATHER CONTINUING INTO EARLY NEXT WEEK. AGREEMENT DOES, HOWEVER, COME IN THE UNSEASONABLY COOL UPPER LEVEL TROUGH OVER THE NORTHEASTERN STATES THROUGH ABOUT SUNDAY BEFORE FILLING AND MOVING OFFSHORE EARLY NEXT WEEK. MAX TEMPERATURES FOR FRIDAY AND SATURDAY WILL RUN SOME 10-15F BELOW NORMAL FOR LATE MAY -- MAKING IT FEEL MORE LIKE PATRIOT`S DAY THAN MEMORIAL DAY WEEKEND. EVENTUALLY BY THE BEGINNING OF NEXT WEEK A RETURN TO MORE SEASONABLY WARM TEMPERATURES WILL RETURN. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM...LIFR/IFR CONDITIONS TODAY IN FOG/DRIZZLE/SHOWERS/ STRATUS. SOME IMPROVEMENT TO MVFR IN BETWEEN PERIODS OF RAIN. DETERIORATING CONDITIONS EXPECTED AGAIN TONIGHT. LONG TERM...MVFR/IFR CONDITIONS THURSDAY NIGHT WILL PERSIST THROUGH FRIDAY AND GRADUALLY GIVE WAY TO VFR CLEAR CONDITIONS BY SUNDAY. && .MARINE... SHORT TERM...A SMALL CRAFT HAS BEEN ISSUED BEGINNING THURSDAY AT NOON AND LASTING THROUGH FRIDAY. OTHERWISE FOG...DRIZZLE...AND SHOWERS ARE EXPECTED TO SIGNIFICANTLY REDUCE VISIBILITIES. LONG TERM...WITH THE FRONT/SURFACE LOW IN THE GULF OF MAINE INTO THE WEEKEND, EXPECT SMALL CRAFT ADVISORY CONDITIONS IN THE COASTAL WATERS TO EXTEND AT LEAST INTO FRIDAY AND SATURDAY. && .FIRE WEATHER... NO ISSUES ANTICIPATED THE REMAINDER OF THIS WEEK DUE TO WET CONDITIONS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON THURSDAY TO NOON EDT FRIDAY FOR ANZ150>154. && $$ SHORT TERM...HANES LONG TERM...STJEAN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
212 PM EDT WED MAY 22 2013 .SYNOPSIS... UPPER LEVEL IMPULSES BRINGS AN INCREASE IN SHOWERS AND THUNDERSTORMS THROUGH THURSDAY NIGHT...UNTIL A COLD FRONT CROSSES. MUCH COOLER WEATHER IS FORECAST THIS HOLIDAY WEEKEND UNDER HIGH PRESSURE. && .NEAR TERM /THROUGH THURSDAY/... DAYTIME HEATING CONTINUES TO PUSH OUR TEMPERATURES CLOSE TO THE CONVECTIVE THRESHOLD. 16Z MESOANALYSIS ILLUSTRATES NO CINH LEFT AND EQUIV POTENTIAL TEMPS BUILDING. STILL A FAIR AMOUNT OF UNCERTAINTY WITH THE DEVELOPMENT OF STORMS AND HOW STRONG STORMS WILL BE LATER TODAY AND TONIGHT. LATEST THINKING IS STORMS WILL DEVELOP ALONG THE THETA-E RIDGE AXIS WHICH IS BUILDING ACROSS WV AND WRN PA. TERRAIN INDUCED STORMS ARE ALREADY UNDERWAY OVER THE CENTRAL MTNS OF WV. FARTHER W ACROSS OHIO...NOT SURE HOW MUCH DEVELOPMENT WILL OCCUR THIS AFTERNOON UNTIL S/W TROUGH PASSES AROUND 0Z. LIKELY POPS STILL ARE ON TRACK FOR THIS EVENING FOR THE ENTIRE AREA. IF THE LATEST HRRR IS CORRECT WE COULD SEE SOME LOCALIZED HIGH WATER POTENTIAL OVER NRN WV WITH TRAINING OF STORMS. AFTER MIDNIGHT THINGS SHOULD QUIET DOWN AS LLVLS STABILIZE AND WE AWAIT MAIN TROF AXIS TO TRAVERSE FROM THE WEST. NAM AND GFS AGREE ON A PERIOD OF DRY OR ISOLD ACTIVITY TMRW FROM LATE MRNG THROUGH MID AFTERNOON BEFORE UPPER LEVEL IMPULSES CROSS. DO NOT FORESEE A SEVERE WEATHER THREAT THURSDAY DUE TO LACK OF HEATING AS AN ABUNDANCE OF CLOUDS WILL BE PRESENCE KEEPING THERMODYNAMICS LOW. GREATEST CHALLENGE IS IF NAM SCENARIO OF A BATCH OF TSTMS RIDING NE FROM WV INTO SWRN PA AROUND DAYBREAK MATERIALIZES. FOR NOW...HELD OFF IN FAVOR OF CONTINUITY PER LOW CONFIDENCE ON THIS OUTCOME. 98 && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... A RAPID TRANSITION TO MUCH COLDER CONDITIONS TAKES PLACE DURING THIS PERIOD AS THE CONSENSUS OF THE MORE RELIABLE GLOBAL MODEL SYSTEMS SUGGESTING THE MID-LEVEL SYSTEM TRACKING THROUGH THE REGION SHOULD CLOSE OFF AS IT MOVES OVER PITTSBURGH AND SLOWLY OOZES SOUTHEASTWARD. THE CLOSED SOLUTIONS FAVORED BY THE MORE RELIABLE MODELS END UP TRENDING TOWARD THE SLOWER END OF THE GUIDANCE PACK WITH THIS SYSTEM...WHICH MAKES SENSE GIVEN THE HIGHER LONG WAVE AMPLITUDE. AS SUCH...THE SYSTEMS DEPARTURE WAS SLOWED IN THE FORECAST WHICH RESULTED IN INCREASING POPS INTO FRIDAY. WHILE ITS DEPARTURE IS SLOWER...MUCH DRIER AIR DOES WORK INTO THE AREA BY FRIDAY NIGHT WITH THE CONSENSUS OFFERING EXTREMELY LEAN LAYER RH PROFILES AND WEAKENING NORTHWEST COLD ADVECTION. THIS SETS THE STAGE FOR STELLAR RADIATIONAL COOLING GOING INTO SATURDAY MORNING. GRIDDED GUIDANCE SUGGESTS WIDESPREAD 30S ACROSS THE AREA...WHICH WITH 850 MB TEMPERATURES FALLING TOWARD -2C IS NOT TOO SHOCKING. FROST WAS ADDED TO THE GRID TO ACCOMMODATE LOWS GENERALLY IN THE MID 30S ACROSS VAST TRACTS OF THE CWA...AND FROST/FREEZE HEADLINES SEEM POSSIBLE AT THIS POINT. THESE TEMPERATURES AT 850 MB FAIL TO MODERATE DURING THE DAY SATURDAY MUCH...SO TEMPERATURES WILL LIKELY ONLY WANDER FOR HIGHS FROM THE UPPER 50S FRIDAY TOWARD THE LOWER 60S SATURDAY. FRIES && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... SIMILAR CONDITIONS PERSIST THROUGH THE REST OF THE WEEKEND AND EVEN POSSIBLY INTO MONDAY MORNING WITH VERY DRY CONDITIONS AND LIGHT WINDS FAVORING SUPERIOR RADIATIONAL COOLING EACH NIGHT. AS SUCH...LOWS CONTINUE TO LOOK TO HEAD TOWARD THE 30S EACH NIGHT...WITH A FEW LOCATIONS INEVITABLY DROPPING BELOW FREEZING. ONCE AGAIN...FROST WAS ADDED TO THE FORECAST INTO THE OVERNIGHT/EARLY MORNINGS THIS WEEKEND...AND FROST/FREEZE HEADLINES AGAIN SEEM QUITE POSSIBLE. OTHERWISE...VERY GRADUAL MODERATION OF LOW LEVEL TEMPERATURES WILL BE LIKELY AS THE CLOSED SYSTEM DEPARTS EASTWARD BUT DRY CYCLONIC NORTHWESTERLY FLOW ALOFT REMAINS THE LARGE CONTROLLING FACTOR FOR OUR WEATHER. THIS IS THANKS IN PART TO THE FACT THAT THE MODEL CONSENSUS KEEPS THE LARGE SCALE RIDGE AXIS LARGELY TO OUR WEST THROUGH THE MIDDLE OF NEXT WEEK. AS A RESULT...CONDITIONS SHOULD REMAIN GENERALLY DRY WITH VERY SLOW MODERATION OF TEMPERATURES THROUGH THE WEEK. FRIES && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... LOW TO MEDIUM CONFIDENCE FORECAST ON SHOWER AND THUNDERSTORM TIMING. VFR WEATHER WILL PREVAIL MUCH OF THE FCST PERIOD /AT LEAST INTO THE OVERNIGHT HOURS/...THE CHALLENGE IS TIMING ON ANY SHRA OR TSRA IMPACTING THE TERMINALS. MAINTAINED VCTS FOR LATE AFTERNOON AND EVENING BEFORE TRANSITIONING TO VFR SHRA UNTIL MIDNIGHT. CLOUDS WILL DEVELOP IN THE PREDAWN HOURS...LATEST GUIDANCE SUGGEST CIGS IN THE 015-025 WHICH IS HIGHER THAN EARLIER RUNS AND IN LINE WITH ONGOING FORECAST. STRATOCU WILL LIFT BY MID MRNG INTO A LOW END VFR DECK. FOR PLACES THAT EXPERIENCE RAINFALL...PATCHY FOG COULD DEVELOP DURING THE PREDAWN HOURS. 98 .OUTLOOK.../THURSDAY THROUGH SUNDAY/... THE PROBABILITY OF WIDESPREAD IFR WEATHER IS LOW. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
117 PM EDT WED MAY 22 2013 .SYNOPSIS... UPPER LEVEL IMPULSES BRINGS AN INCREASE IN SHOWERS AND THUNDERSTORMS THROUGH THURSDAY NIGHT...UNTIL A COLD FRONT CROSSES. MUCH COOLER WEATHER IS FORECAST THIS HOLIDAY WEEKEND UNDER HIGH PRESSURE. && .NEAR TERM /THROUGH THURSDAY/... DAYTIME HEATING CONTINUES TO PUSH OUR TEMPERATURES CLOSE TO THE CONVECTIVE THRESHOLD. 16Z MESOANALYSIS ILLUSTRATES NO CINH LEFT AND EQUIV POTENTIAL TEMPS BUILDING. STILL A FAIR AMOUNT OF UNCERTAINTY WITH THE DEVELOPMENT OF STORMS AND HOW STRONG STORMS WILL BE LATER TODAY AND TONIGHT. LATEST THINKING IS STORMS WILL DEVELOP ALONG THE THETA-E RIDGE AXIS WHICH IS BUILDING ACROSS WV AND WRN PA. TERRAIN INDUCED STORMS ARE ALREADY UNDERWAY OVER THE CENTRAL MTNS OF WV. FARTHER W ACROSS OHIO...NOT SURE HOW MUCH DEVELOPMENT WILL OCCUR THIS AFTERNOON UNTIL S/W TROUGH PASSES AROUND 0Z. LIKELY POPS STILL ARE ON TRACK FOR THIS EVENING FOR THE ENTIRE AREA. IF THE LATEST HRRR IS CORRECT WE COULD SEE SOME LOCALIZED HIGH WATER POTENTIAL OVER NRN WV WITH TRAINING OF STORMS. AFTER MIDNIGHT THINGS SHOULD QUIET DOWN AS LLVLS STABILIZE AND WE AWAIT MAIN TROF AXIS TO TRAVERSE FROM THE WEST. NAM AND GFS AGREE ON A PERIOD OF DRY OR ISOLD ACTIVITY TMRW FROM LATE MRNG THROUGH MID AFTERNOON BEFORE UPPER LEVEL IMPULSES CROSS. DO NOT FORESEE A SEVERE WEATHER THREAT THURSDAY DUE TO LACK OF HEATING AS AN ABUNDANCE OF CLOUDS WILL BE PRESENCE KEEPING THERMODYNAMICS LOW. GREATEST CHALLENGE IS IF NAM SCENARIO OF A BATCH OF TSTMS RIDING NE FROM WV INTO SWRN PA AROUND DAYBREAK MATERIALIZES. FOR NOW...HELD OFF IN FAVOR OF CONTINUITY PER LOW CONFIDENCE ON THIS OUTCOME. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... A REINFORCING FRONT IS PROGGED FOR FRIDAY WITH RESIDUAL SHWR CHCS FADING BY AFTN WITH PASSAGE OF THAT FEATURE. AS NW FLOW DVLPS WITH PASSAGE OF THE AFOREMENTIONED PHASED TROF AXIS...COLD ADVCTN WL LIMIT TEMP RECOVERY. EXPECT HIGHS ABOUT 10 DEGREES BELOW THE SEASONAL AVERAGES UNDR THE RESULTING HIGH AMPLITUDE...ERN CONUS TROF PTN. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... THE MODELS ARE IN GOOD AGREEMENT ON THE OVERALL UPPER LEVEL PATTERN THROUGH THE EXTENDED WITH AN UPPER LEVEL RIDGING OF THE CENTRAL CONUS AND TROUGHING IN BOTH THE WEST AND EAST. WHILE THIS WOULD GENERALLY LEAD TO A MUCH LESS THAN CONFIDENT FORECAST IN THE SHORTWAVES WITHIN THE FLOW...THIS DOESN`T SEEM TO BE THE CASE AS BOTH THE GFS AND ECMWF SUGGEST THAT MUCH OF THE PRECIPITATION WILL BE SUPPRESSED SOUTH OF THE REGION THROUGH MUCH OF THE PERIOD. THUS...OPTED TO TAKE A BLEND OF THE MODELS AND HPC GUIDANCE. ALSO...HEDGED A BIT COOLER WITH TEMPERATURES WITH NORTHWEST FLOW PRESENT ESPECIALLY FOR THE FIRST HALF OF THE PERIOD. THIS KEPT TEMPERATURES BELOW SEASONAL AVERAGES SAT/SUN BEFORE MODERATING CLOSER TO NORMAL FOR THE REST OF THE PERIOD. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... LOW TO MEDIUM CONFIDENCE FORECAST ON SHOWER AND THUNDERSTORM TIMING. VFR WEATHER WILL PREVAIL MUCH OF THE FCST PERIOD /AT LEAST INTO THE OVERNIGHT HOURS/...THE CHALLENGE IS TIMING ON ANY SHRA OR TSRA IMPACTING THE TERMINALS. MAINTAINED VCTS FOR LATE AFTERNOON AND EVENING BEFORE TRANSITIONING TO VFR SHRA UNTIL MIDNIGHT. CLOUDS WILL DEVELOP IN THE PREDAWN HOURS...LATEST GUIDANCE SUGGEST CIGS IN THE 015-025 WHICH IS HIGHER THAN EARLIER RUNS AND IN LINE WITH ONGOING FORECAST. STRATOCU WILL LIFT BY MID MRNG INTO A LOW END VFR DECK. FOR PLACES THAT EXPERIENCE RAINFALL...PATCHY FOG COULD DEVELOP DURING THE PREDAWN HOURS. .OUTLOOK.../THURSDAY THROUGH SUNDAY/... THE PROBABILITY OF WIDESPREAD IFR WEATHER IS LOW. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ SYNOPSIS...98 NEAR TERM...98 SHORT TERM...15 AVIATION...98
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1005 AM EDT WED MAY 22 2013 .SYNOPSIS... HIGH PRESSURE PERSISTING OVER THE ATLANTIC WITH WARM AND HUMID CONDITIONS UNTIL A COLD FRONT THURSDAY NIGHT. AN UPPER TROUGH WILL LINGER OVER THE AREA FRIDAY WITH HIGH PRESSURE BUILDING THROUGH SATURDAY. A FRONTAL BOUNDARY STALLS OUT ACROSS THE MID- ATLANTIC SUNDAY NIGHT THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... HIGH PRESSURE BOTH AT THE UPPER-LEVELS AND THE SURFACE WILL REMAIN OVER THE ATLANTIC OCEAN THROUGH TONIGHT. AN UPPER-LEVEL TROUGH WILL SLOWLY SHIFT FROM THE CENTRAL CONUS INTO THE GREAT LAKES. A SOUTHERLY FLOW AROUND THE HIGH WILL CONTINUE TO USHER IN WARM AND HUMID CONDITIONS ACROSS OUR AREA. LOW CLDS AND FOG ASSOCD WITH THE NOCTURNAL INVERSION LESS PRONOUNCED THAN YDA...AND ITS BURNING AWAY QUICKER. THEREFORE... THERE SHUD BE LESS OF A MAXT SPREAD THAN THERE WAS YDA. STILL...HV TWEAKED I-95 CRRDR DOWN A DEGF OR TWO TO ACCNT FOR ITS IMPACT. THE WARM AND HUMID AIRMASS IN PLACE WILL LEAD TO HIGH AMOUNTS OF INSTABILITY. UNMODIFIED LWX RAOB REFLECTS THIS...BUT ALSO HIGHLIGHTS THE CAPPING INHIBITION BTWN H9-8. HGTS SHUD BE DROPPING TAFTN AS TROF AXIS CROSSES THE WRN GRTLKS. MODIFYING THE SNDG FOR T/TD 88/68 YIELDS ARND 3000 J/KG OF SBCAPE W/O A CAP. MLCAPE MUCH MORE RESERVED AND SLGTLY INHIBITED. TERRAIN CIRCULATIONS AND A SURFACE TROUGH WILL ACT AS LIFTING MECHANISMS FOR CONVECTION THIS AFTERNOON. THIS IS ALSO SIMILAR TO TUESDAY. THEREFORE...A BETTER CHANCE FOR THUNDERSTORMS EXISTS THIS AFTERNOON AND EVENING...ESPECIALLY NEAR AND WEST OF THE I-95 CORRIDOR. HV ADJUSTED POPS SLGTLY TO PLACE MORE EMPHASIS ON APLCHNS AND DEEMPHASIZE INVOF CHESPK BAY. HRRR /WRF-ARW4 BOTH SUGGEST THAT TSRA SHUD FIRE TAFTN W OF THE BLURDG...SPCLY AFTR 18Z. WL NEED TO WATCH THAT TIMING THO...AS RADAR TRENDS IN WVA ATTM SUGGEST IT MAY BE ERLR. ALTHOUGH WIDESPREAD SEVERE WEATHER WILL LIKELY HOLD OFF TO OUR WEST FOR LOCATIONS CLOSER TO THE UPPER-LEVEL TROUGH...THERE IS A THREAT FOR LOCALLY DAMAGING WIND GUSTS AND LARGE HAIL IN ANY THUNDERSTORMS THAT DO DEVELOP DUE TO THE HIGH INSTABILITY. CONVECTION WILL LIKELY DISSIPATE LATER THIS EVENING DUE TO THE LOSS OF DAYTIME HEATING. HOWEVER...AN UPPER-LEVEL DISTURBANCE IS EXPECTED TO PASS THROUGH THE REGION LATE TONIGHT AS THE UPPER-LEVEL TROUGH CONTINUES TO SLIDE CLOSER TO OUR AREA. PLENTY OF MOISTURE AND FORCING FROM THE UPPER-LEVEL DISTURBANCE MAY RESULT IN SCATTERED SHOWERS/T-STORMS TOWARD MORNING. MIN TEMPS TONIGHT WILL RANGE FROM THE 50S IN THE MOUNTAINS TO THE LOWER AND MIDDLE 70S IN DOWNTOWN WASHINGTON/BALTIMORE. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... THURSDAY LOOKS TO BE THE LAST ABOVE NORMAL TEMPERATURE DAY FOR AWHILE AHEAD OF THE COLD FRONT THAT CROSSES THURSDAY NIGHT TIMEFRAME. PREFRONTAL LINES/CLUSTERS OF SHOWERS/THUNDERSTORMS PROGRESS EAST ACROSS THE AREA THURSDAY INTO THURSDAY NIGHT. GFS BUFR SNDG FOR KIAD PROGS A 1.6 INCH PWAT WHICH IS CERTAINLY HIGH...BUT JUST SHY OF THE 2 STDEV INDICATOR OF FLASH FLOODING. WITH PROGRESSIVE NATURE OF THE ACTIVITY...ANY FLASH FLOODING WOULD BE LOCALIZED. DAMAGING WIND THREAT...PARTICULARLY WITH HEATING ON THURSDAY IS ABLE TO PEAK BEFORE ORGANIZED ACTIVITY MOVES THROUGH. FRIDAY...UPR TROUGH DRIFTS EAST OVER THE AREA WITH BACK EDGE OF CLOUDS SLOW TO COME IN THE AFTERNOON. GUSTY NWLY FLOW FRIDAY CONTINUES AS HIGH PRESSURE BUILDS THROUGH SATURDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... SHORTWAVE FROM TN VLY ON SUNDAY NOW LOOKS TO EXPAND EAST ACROSS THE SOUTHERN-CENTRAL MID-ATLANTIC. CONVERGENCE ALONG THIS BOUNDARY WOULD SET OFF SHOWERS. PATTERN IS STALLED INTO MID NEXT WEEK...SO A PROLONGED CLOUDY/RAINY PERIOD IS POSSIBLE. THIS WOULD RESULT IN BELOW NORMAL TEMPS. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... LOW CLOUDS BURNING OFF ATTM. MVFR AT DCA/MTN...BUT ANTICIPATE VFR EVERYWHERE BY 15Z. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP AFTN...PRIMARILY INVOF MRB. SOME OF THE THUNDERSTORMS WILL BE CAPABLE OF PRODUCING GUSTY WINDS AND LARGE HAIL. AREAS OF LOW CLOUDS ARE POSSIBLE LATE TONIGHT ALONG WITH SCATTERED SHOWERS/T-STORMS. THUNDERSTORMS THURSDAY INTO THURSDAY EVENING AHEAD OF A COLD FRONT. IFR CONDS POSSIBLE IN THE HEAVIEST ACTIVITY. SLY FLOW UNTIL A COLD FROPA THURSDAY NIGHT. NWLY FLOW WITH GUSTS 25 TO POSSIBLY 30 KT WITH MID LEVEL CIGS FRIDAY. NWLY FLOW CONTINUES THROUGH SATURDAY AS HIGH PRESSURE BUILDS. && .MARINE... HIGH PRESSURE WILL REMAIN OVER THE ATLANTIC OCEAN THROUGH TONIGHT. A SOUTHERLY FLOW WILL CONTINUE OVER THE WATERS DURING THIS TIME. A SMALL CRAFT ADVISORY REMAINSS IN EFFECT FOR PORTIONS OF THE WATERS THROUGH TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE LATER THIS AFTERNOON AND EVENING. ANY THUNDERSTORMS THAT DO DEVELOP WILL BE CAPABLE OF PRODUCING GUSTY WINDS AND HAIL. SLY FLOW AHEAD OF A LATE THURSDAY NIGHT COLD FRONT. SCA EXPANDED THROUGH THURSDAY. EXPECT AN EXTENSION THURSDAY NIGHT FOR PREFRONTAL SLY FLOW...THEN NWLY FLOW AROUND 25 KT FRIDAY THROUGH SATURDAY AS HIGH PRESSURE BUILDS. && .TIDES/COASTAL FLOODING... A SOUTHERLY FLOW WILL CONTINUE OVER THE WATERS THROUGH THURSDAY NIGHT...BUT THE FLOW MAY REMAIN JUST WEST OF SOUTH. TIDAL ANOMALIES WILL LIKELY INCREASE A LITTLE...BUT WITH THE FLOW REMAINING WEST OF SOUTH THE WATER LEVELS SHOULD REMAIN BELOW THRESHOLDS FOR MINOR COASTAL FLOODING. THE CLOSEST WATER LEVELS WILL COME TO MINOR FLOODING THRESHOLDS WILL BE DURING THE HIGH TIDE CYCLE LATE WEDNESDAY NIGHT AND LATE THURSDAY NIGHT...THE HIGHER OF THE TWO HIGH TIDES. TIDAL ANOMALIES WILL DECREASE FRIDAY BEHIND A COLD FRONT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EDT THURSDAY FOR ANZ530-531-539. SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT THURSDAY FOR ANZ535- 538. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM EDT THURSDAY FOR ANZ532-536-540-542. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ533-534- 537-541-543. && $$ SYNOPSIS...BJL NEAR TERM...HTS/BJL SHORT TERM...BAJ LONG TERM...BAJ AVIATION...HTS/BJL/BAJ MARINE...KLEIN/BJL/BAJ TIDES/COASTAL FLOODING...BJL
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1026 PM EDT THU MAY 23 2013 .SYNOPSIS... ISSUED AT 357 PM EDT THU MAY 23 2013 HIGH PRESSURE IS BUILDING INTO NORTHERN MICHIGAN TONIGHT...TO PUT THE KIBOSH ON THE SOGGY CONDITIONS AND USHER IN A BEAUTIFUL HOLIDAY WEEKEND. THAT HIGH PRESSURE SYSTEM WILL STICK AROUND THROUGH AT LEAST MONDAY...PROVIDING PLENTY OF SUNNY BUT SEASONABLY COOL DAYS AND CHILLY NIGHTS. SO CHILLY IN FACT...THAT FROST WILL BE POSSIBLE OVER THE NEXT COUPLE NIGHTS. && .UPDATE... ISSUED AT 1026 PM EDT THU MAY 23 2013 SKIES HAVE CLEARED ACROSS MOST OF OUR CWA...WITH ONLY SOME LINGERING SC ACROSS PORTIONS OF NE LWR MICHIGAN ATTM. ONLY FLY IN THE CLEAR SKY OINTMENT FOR THE OVERNIGHT HOURS MAY BE A BANK OF LOW CLOUDS DROPPING SOUTH THRU ERN ONTARIO. NAM AND GFS ARE NOT HANDLING THIS AREA OF LOW CLOUDS WELL...THE RUC DOES ELUDE TO SOME LOW LEVEL MOISTURE DROPPING SOUTH ALONG THE ERN EDGE OF THE SURFACE RIDGE...BUT ACTUALLY KEEPS THIS MOISTURE EAST OF OUR CWA. WILL CERTAINLY NEED TO KEEP AN EYE ON THIS AREA OF LOW CLOUDS TO SEE IF IT GRAZES OUR ERN CWA. THIS WILL CERTAINLY HAVE AN IMPACT ON LOW TEMPS AND FROST POTENTIAL OVERNIGHT. FOR NOW...WILL MAKE SOME UPWARD ADJUSTMENTS TO CLOUD COVER FOR OUR ERN COUNTIES...BUT WILL FALL SHORT OF A MOSTLY CLOUDY FORECAST. WILL KEEP THE FROST ADVISORY IN TACT FOR ALL AREAS FOR NOW...BUT AGAIN WILL NEED TO KEEP AN EYE ON THIS CLOUD COVER AND ITS POTENTIAL IMPACT ON OVERNIGHT LOWS AND FROST DEVELOPMENT. UPDATE ISSUED AT 718 PM EDT THU MAY 23 2013 SKIES CONTINUE TO CLEAR FROM NW TO SE ACROSS OUR CWA THIS EVENING AS STRONG CANADIAN HIGH PRESSURE AND DRY AIR THRU THE COLUMN BUILD INTO THE WRN GREAT LAKES REGION. AS SKIES CLEAR AND WINDS DIMINISH WITH SUNSET...TEMPS WILL QUICKLY FALL THRU THE 40S AND INTO THE 30S OVERNIGHT. FROST DEVELOPMENT IS STILL A GOOD BET GIVEN CURRENT DWPTS IN THE LOW 30S. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 357 PM EDT THU MAY 23 2013 ON THE LATEST SURFACE WEATHER MAP...1033 MB HIGH PRESSURE WAS OVER NORTHERN MANITOBA CANADA WITH 1004 MB LOW PRESSURE OVER NORTHEAST NEW YORK STATE. APX AND SURROUNDING RADARS SHOW THE BACK EDGE OF DEPARTING RAINFALL EXITING INTO LAKE HURON. SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOWS MARKED CLEARING ADVECTING IN FROM THE NORTH AND WEST. THE MAIN SHORT TERM FORECAST CONCERN REVOLVES AROUND LOW TEMPERATURES AND ASSOCIATED FROST/FREEZE HEADLINES TONIGHT. TONIGHT...UNSEASONABLY COLD AIR ASSOCIATED WITH ARCTIC TYPE HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTHWEST. THIS WILL RESULT IN SLOWLY DIMINISHING WINDS AND MAINLY CLEAR SKIES. THERE ARE A COUPLE OF COMPETING FACTORS TO CONTEND WITH AS FAR AS LOW TEMPERATURES GO. BOUNDARY LAYER WINDS DO NOT LOOK LIKE THEY FULLY DECOUPLE WITH 950 MB WINDS REMAINING IN THE 15 TO 20 KNOT RANGE THROUGH 12Z FRIDAY. HOWEVER...FROM A PURE COLD ADVECTION STANDPOINT WITH 850 MB TEMPERATURES BOTTOMING OUT BETWEEN -2 AND -3 C...TEMPERATURES SHOULD NOT HAVE MUCH OF A PROBLEM FALLING THROUGH THE 30S. COULD EVEN SEE SOME SHELTERED SPOTS HIT THE UPPER (OR EVEN MIDDLE 20S). SO AT A MINIMUM...TEMPERATURES EXPECTED TO BE COLD ENOUGH TO SUPPORT FROST (THOUGH THE EXTREMELY DRY AIR MASS VOID OF MUCH MOISTURE IN ITSELF MAY NOT PRODUCE MUCH ACTUAL FROST) IN ADDITION...TEMPERATURES IN A FEW SHELTERED SPOTS COULD SUPPORT A FREEZE (BUT THIS IS NOT EXPECTED TO BE WIDESPREAD). SO WITH ALL THIS IN MIND...WILL CONTINUE WITH THE ONGOING FROST ADVISORY...AS WELL AS AN EXPANSION EASTWARD INTO THE REMAINING COUNTIES BORDERING LAKE HURON. FRIDAY...HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTHWEST WITH A VERY SLOW MODIFICATION IN TEMPERATURES. MODEL SOUNDING/CROSS SECTIONS ARE VERY DRY...SUPPORTING LITTLE TO NO CLOUD COVER...SO MOSTLY SUNNY CONDITIONS ARE EXPECTED. TEMPERATURES ARE STILL EXPECTED TO BE A GOOD 10 TO 15 DEGREES BELOW AVERAGE FOR LATE MAY WITH HIGHS ONLY IN THE MIDDLE 50S TO AROUND 60. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 357 PM EDT THU MAY 23 2013 RECENT TRENDS: TEMPERATURES...WARMING TREND LAST SEVEN DAYS ACROSS NORTHERN MICHIGAN (ABOUT 2-4C ABOVE AVERAGE) THOUGH NOT A GREAT START OUT THERE TODAY. 1-3C ABOVE NORMAL FOR THE MONTH OF MAY THUS FAR. PRECIPITATION/HYDROLOGY: SIGNIFICANT RAINFALL LAST COUPLE OF DAYS...SOME LOCALES PICKING UP 2-3+ INCHES OF PRECIP. OVERALL SOIL MOISTURE (TOP 1M) STILL ABOVE NORMAL...TOP 25CM MOSTLY BELOW 50 PERCENT CAPACITY. AREA RIVERS ON THE RISE AFTER RAINFALL...RIFLE RIVER NEAR STERLING ALREADY IN FLOOD WITH A FORECAST RISE OF ANOTHER 1.5 FEET OR SO. GREAT LAKES: WATER TEMPERATURES AVERAGING 4-5C NORTHERN LAKES MICHIGAN/HURON...AROUND 6-7C FROM BEAVER ISLAND NORTH AND EAST TO THE STRAITS. LAKE SUPERIOR/WHITEFISH BAY AROUND 3C. LARGE SCALE PATTERN/FORECAST: SMALL-SCALE OMEGA BLOCKING PATTERN ACROSS NORTH AMERICA WITH TROUGHS EAST AND WEST AND A NARROW RIDGE IN BETWEEN. OVERALL RECENT PATTERN HAS BEEN PRETTY PROGRESSIVE (45 DAY HOVMOLLER ANALYSIS REFLECTS THIS RATHER NICELY)...THOUGH THE CURRENT BLOCKING WILL KEEP THINGS HEMMED IN A BIT WITH EAST COAST CYCLOGENESIS THIS WEEKEND HELPING BOG THINGS DOWN. BUT THE OVERALL TREND INTO NEXT WEEK SHOULD BE RISING HEIGHTS ACROSS THE EAST WITH MORE PERSISTENT TROUGHING OUT WEST (AND THUS AN OVERALL WARMING TREND). HIGH PRESSURE BUILDS INTO THE GREAT LAKES THIS WEEKEND AND GETS STUCK BETWEEN AFOREMENTIONED EAST COAST CYCLONE AND LEE CYCLOGENESIS ACROSS THE CENTRAL HIGH PLAINS. WATER VAPOR IMAGERY SHOWS A COMPACT VORTICITY CENTER CROSSING 60N INTO NORTHERN MANITOBA THIS AFTERNOON THAT IS FORECAST TO FLY BY EAST OF MICHIGAN EARLY SATURDAY...BUT OTHERWISE NOT MUCH EXPECTED SYNOPTICALLY THROUGH SUNDAY. MAIN FORECAST CONCERNS LOOK TO REVOLVE AROUND TEMPERATURES AND FROST POTENTIAL THIS WEEKEND. FRIDAY NIGHT THROUGH SUNDAY: SHORT WAVE TROUGH/JET STREAK WILL DROP ACROSS LAKE HURON FROM THE NORTHWEST FRIDAY NIGHT...DISTURBANCE DOES HAVE AN AREA OF CIRRUS WITH IT THAT WILL FLOAT ACROSS FOR A TIME. WILL PROBABLY HAVE SOME IMPACT ON LOW TEMPERATURES BUT STILL EXPECT A CHILLY NIGHT WITH LOWS DROPPING INTO THE 30S WITH SOME THREAT FOR FROST ACROSS THE INTERIOR. PARTLY TO MOSTLY SUNNY SATURDAY...DEEP MIXING WILL ALLOW TEMPERATURES TO WARM INTO THE 60S THOUGH MAY STILL FALL A BIT SHORT OF AVERAGE FOR THE DAY. SIMILAR STORY ON TAP FOR SATURDAY NIGHT...CLEAR/CLEARING SKIES AND LIGHT/CALM WINDS WITH SURFACE RIDGE STUCK IN PLACE. PLAN TO MENTION FROST POTENTIAL SUNDAY MORNING WITH LOWS ACROSS THE INTERIOR IN THE LOWER-MID 30S. PLENTY OF SUN EXPECTED SUNDAY AFTERNOON ALONG WITH SEASONABLE TEMPERATURES. EXTENDED FORECAST (MONDAY THROUGH THURSDAY): HIGH PRESSURE EXPECTED TO HOLD ON INTO THE MEMORIAL DAY HOLIDAY AND LIKELY INTO TUESDAY AS WELL. THERE WILL BE A WARM FRONT ACROSS THE CENTRAL PLAINS AND INTO THE MIDDLE MISSISSIPPI VALLEY THAT WILL BE THE MAIN FOCUS FOR PRECIPITATION INTO NEXT WEEK...HOW QUICKLY THIS FEATURE LIFTS NORTH TOWARD THE GREAT LAKES WILL BE THE ISSUE FOR THE LATTER HALF OF THE EXTENDED PERIODS. TEMPERATURES WILL MODERATE MONDAY/TUESDAY...BUT WILL START GETTING INTO BETTER WARM ADVECTION BY MIDWEEK. MAY ALSO START TO GET NOTICEABLY MORE HUMID...AND BY WEDNESDAY MAY BE ENOUGH INSTABILITY IN PLACE FOR SOME SHOWER/THUNDERSTORM DEVELOPMENT. BETTER CHANCES FOR PRECIPITATION MAY BE IN THE OFFING FOR THURSDAY AS WARM FRONT NUDGES CLOSER. HIGHS MEMORIAL DAY SHOULD BE WELL INTO THE 60S/LOWER 70S...WITH MORE 70S DURING THE MIDWEEK PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 718 PM EDT THU MAY 23 2013 MAINLY SKC IS EXPECTED AT ALL TAF SITES THRU FRIDAY EVENING AS STRONG CANADIAN HIGH PRESSURE AND DRY AIR THRU THE COLUMN BUILD SOUTH INTO MICHIGAN. GUSTY NORTH WINDS WILL DIMINISH WITH SUNSET THIS EVENING...AND THEN BECOME GUSTY AGAIN ON FRIDAY. && .MARINE... ISSUED AT 357 PM EDT THU MAY 23 2013 GUSTY NORTH WINDS THROUGH THIS EVENING DUE TO A TIGHT SURFACE PRESSURE GRADIENT AND STRONG WINDS ALOFT. WINDS ARE THEN EXPECTED TO SLOWLY DIMINISH OVERNIGHT AS HIGH PRESSURE BEGINS TO BUILD INTO THE NEARSHORE WATERS. THEREFORE...HAVE EXTENDED THE SMALL CRAFT ADVISORIES THROUGH LATE EVENING. HIGH PRESSURE IS THEN EXPECTED TO GAIN FULL CONTROL FRIDAY INTO THE HOLIDAY WEEKEND LEADING TO HEADLINE FREE CONDITIONS. && .APX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY FROM 2 AM TO 8 AM EDT FRIDAY FOR MIZ016>036-041- 042. LH...SMALL CRAFT ADVISORY UNTIL 2 AM EDT FRIDAY FOR LHZ345>349. LM...SMALL CRAFT ADVISORY UNTIL 2 AM EDT FRIDAY FOR LMZ323-341-342- 344>346. LS...SMALL CRAFT ADVISORY UNTIL 2 AM EDT FRIDAY FOR LSZ321-322. && $$ UPDATE...MR SYNOPSIS...KAB SHORT TERM...AJS LONG TERM...JPB AVIATION...MR MARINE...AJS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EDT WED MAY 22 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 353 PM EDT WED MAY 22 2013 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLUGGISH UPR LO OVER THE UPR MS RIVER VALLEY BTWN RDG OFF THE SE CONUS AND ANOTHER RDG AXIS OVER THE ROCKIES. BAND OF -SHRA STRETCHING FM NE MN INTO THE WRN CWA UNDER BAND OF H85-7 FGEN TO THE NE OF THE CLOSED LO IS HOLDING FIRM EVEN THOUGH LLVL DRY AIR IS SURGING INTO NE MN/WRN LK SUP IN STEADY NE FLOW BTWN HI PRES OVER NRN MANITOBA AND SFC LO PRES IN THE LOWER LKS. ANOTHER LARGER AREA OF SHRA/ISOLD TS OVER THE SE HALF OF WI/S HALF OF LK MI IS EXPANDING TO THE N AS SHRTWV OVER IL/LEFT EXIT REGION OF SUPPORTING H3 JET MAX IS MOVING N OF THE CLOSED LO. OTRW...LO CLDS HAVE BEEN QUITE PERSISTENT OVER UPR MI WITH CHILLY NE WIND OFF LK SUP. SOME FOG HAS PERSISTED AS WELL NEAR LK SUP E OF THE KEWEENAW...WHERE THE LLVL DRY AIR HAS NOT YET ARRIVED. MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE HOW DRIER AIR ARRIVING FM THE N WL IMPACT POPS ASSOCIATED WITH BAND OF FGEN OVER THE WRN ZNS AND AREA OF SHRA MOVING N TOWARD THE SE COUNTIES. TNGT...UPR LO NOW OVER SE MN IS PROGGED TO DRIFT ESE...AND NAM SHOWS BAND OF H85-7 FGEN/H85-5 QVECTOR CNVGC FOLLOWING THIS FEATURE SEWD ACRS MAINLY THE W HALF OF THE CWA. AT THE SAME TIME...H7-3 QVECTOR CNVGC/UPR DVGC IN LEFT EXIT AHEAD OF SHRTWV/SUPPORTING UPR JET LIFTING NNEWD WL IMPACT MAINLY THE SE COUNTIES. LOOKS LIKE THESE DYNAMICS MAY INTERACT FOR A TIME LATE THIS AFTN/EARLY EVNG OVER THE SE ZNS. SO HIER POPS IN THIS AREA AT THAT TIME SEEM APPROPRIATE. AT THE SAME TIME...DRIER AIR SURGING INTO THE NW CWA UNDER STRONGER NNE FLOW WL END ANY LINGERING PCPN AS FGEN AXIS SHIFTS TO THE SE. THE PCPN WL END EVEN OVER THE SE ZNS AFT 06Z FOLLOWING DEPARTURE OF SHRTWV/ACCOMPANYING DYNAMICS AND ARRIVAL OF DRIER LLVL AIR. THE ARRIVAL OF THE DRIER LLVL AIR AND EXIT OF THE DYNAMICS WL ALLOW FOR SOME CLRG...BUT THE UPSLOPE NNE FLOW MAY SLOW THE PROCESS OVER THE HIER TERRAIN NEAR LK SUP. THU...HI PRES IS FCST TO BLD INTO THE UPR LKS...RESULTING IN DRY WX. ALTHOUGH LINGERING H85 THERMAL TROF WITH TEMPS ARND 0C THRU 00Z WOULD INDICATE QUITE A BIT OF DIURNAL CU/SC AT THIS TIME OF YEAR OVER LAND...DRYNESS OF INCOMING AIRMASS AS WELL AS LLVL ACYC/ DIFFLUENT FLOW WL RESULT IN MOCLR SKIES. IF THERE IS ANY UPSLOPE SC OVER THE HIER TERRAIN NEAR LK SUP...THIS CLD WL MIX OUT EARLY. THE FCST H85 TEMPS AND MIXING TO H8-85 ON NAM FCST SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 50S OVER THE INTERIOR. BUT STIFF NNE WIND OFF LK SUP WL CAUSE TEMPS TO HOLD IN THE 40S NEAR THE BIG LAKE. THESE STRONGER NE WINDS WL DIMINISH OVER THE W IN THE AFTN WITH THE APRCH OF THE HI CENTER/WEAKENING PRES GRADIENT. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 353 PM EDT WED MAY 22 2013 SLOW MOVING AND RATHER STABLE UPPER AIR PATTERN EXPECTED THROUGH THE ENTIRE LENGTH OF THE LONG TERM. INITIALLY LATE THIS WEEK...THERE IS A TROUGH OVER PACIFIC NORTHWEST WITH RIDGING OVER CENTRAL CONUS... AND TROUGHING OVER MUCH OF EASTERN CANADA ACROSS THE GREAT LAKES. EXPECT BELOW NORMAL TEMPERATURES TO PREVAIL THROUGH THE HOLIDAY WEEKEND AS THE TROUGH ONLY SLOWLY MOVES TO THE EAST. EVENTUALLY... WARMER TEMPERATURES ARE EXPECTED BY MIDDLE OF NEXT WEEK WHEN RIDGING EXPANDS FROM PLAINS ACROSS THE GREAT LAKES. AFTER AN UNSETTLED AND WET WEEK THAT HAS OCCURRED OVER THE UPPER GREAT LAKES...HUDSON BAY HIGH PRESSURE RIDGING ACROSS THE GREAT LAKES SHOULD BRING A PROLONGED PERIOD OF DRY WEATHER INTO NEXT WEEK. CERTAINLY POSSIBLE THIS DRY WEATHER STRETCH MAY EVEN PERSIST INTO THE MIDDLE OF NEXT WEEK. WARM FRONT FORMING TO THE SOUTH AND WEST OF UPPER MICHIGAN WILL RESULT IN SOME SMALLER CHANCES OF PRECIP BY NEXT WEDNESDAY... BUT GIVEN THE VERY DRY AIRMASS IN PLACE...GREATEST CHANCE OF SHOWERS AND STORMS WILL LIKELY STAY TO WEST OF UPPER LAKES CLOSER TO AXIS OF HIGHER H85-H7 MOISTURE AND INSTABILITY. GUSTY WINDS AROUND ON THURSDAY DIMINISH BY THE WEEKEND AS HIGH PRESSURE BUILDING SOUTH OUT OF NORTHERN ONTARIO BECOMES MORE ESTABLISHED. LIGHTER WINDS ON THURSDAY NIGHT AND VERY DRY AIRMASS OVERHEAD DUE TO STRONG MIXING EARLIER IN THE DAY WILL SUPPORT MIN TEMPS DROPPING TO AROUND 20 DEGREES INTERIOR WEST AND IN THE 20S TO LOWER 30S ELSEWHERE. EXPECT WIDESPREAD FROST FOR MANY AREAS ON THURSDAY NIGHT. WE DO NOT OFFICIALLY BEGIN THE FROST AND FREEZE HEADLINES UNTIL MEMORIAL DAY BUT WILL CONTINUE TO INCLUDE MENTION IN THE GRIDS. WITH STRONG HIGH PRESSURE OVER THE AREA...NEAR 1030MB... LAKE BREEZES MAY GET GUSTY AT TIMES THIS WEEKEND. AFTER A COOLER DAY ALL AREAS ON FRIDAY...COOLING WILL BECOME MORE OF A LAKESIDE FEATURE THROUGH THE WEEKEND AS INLAND AREAS RISE INTO THE 60S. SEEMS THERE IS A SLIM CHANCE OF LGT RAIN/SPRINKLES OVER FAR WEST CWA LATE FRIDAY NIGHT INTO SATURDAY MORNING. 12Z NAM SOUNDINGS SHOW MOISTURE IN MID LEVELS ENHANCED BY RIGHT ENTRANCE REGION OF DEPARTING JET STREAK OVER ONTARIO BUILDING DOWN ENOUGH ALONG WITH SUFFICIENT UVM TO RESULT IN BAND OF LGT SHRA MAKING IT INTO IWD 06Z-12Z ON SATURDAY. ECMWF/GFS SHOW SOME MID LEVEL MOISTURE BUT HAVE QPF STAYING OUT OF CWA. 12Z ECMWF DOES SHOW A BIT NOW THOUGH. NAM SEEMS TOO AGGRESSIVE WITH EASTWARD PUSH OF LGT PRECIP SO WILL NOT PUT A MENTION IN YET. INCREASE IN CLOUDS OVERNIGHT WILL IMPACT MIN TEMPS AND MAY RESTRICT POTENTIAL FOR FROST...AT LEAST IN THE INTERIOR WEST CWA. ELSEWHERE...TEMPS DROPPING INTO THE UPPER 20S OR NEAR 30 DEGREES WILL SUPPORT MORE FROST...ESPECIALLY INLAND FROM THE LAKES. IF THERE ARE BKN CLOUDS WEST...THEY SHOULD DISSIPATE BY SATURDAY EVENING RESULTING IN ANOTHER COOL NIGHT WITH SOME FROST INLAND FROM THE GREAT LAKES SHORES. DUE TO COOL AND DAMP WEATHER AND MODERATE RAIN AMOUNTS IN SOME AREAS /HAD REPORT TODAY OF OVER 4 INCHES TO WEST OF ONTONAGON/...FIRE WEATHER ISSUES ARE TAKING A BRIEF HIATUS. EVENTUALLY DUE TO ALMOST A WEEK OF DRYING...INCREASING SOUTH/SOUTHWEST WINDS...AND WARMER TEMPERATURES INTO THE 70S EARLY-MID NEXT WEEK MAY SEE INCREASING FIRE WEATHER CONCERNS FOR AREAS THAT HAVE NOT EXPERIENCED A FULL GREEN UP AND/OR SEEN A LOT OF RAIN OVER THE LAST FEW DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 123 PM EDT WED MAY 22 2013 AS A STEADY NNE WIND BTWN HI PRES IN SCENTRAL CANADA AND LO PRES OVER THE LWR GRT LKS ADVECTS MUCH DRIER LLVL AIR OVER UPR MI... EXPECT IMPROVING CONDITIONS TO VFR THIS EVNG. CMX WL BE CLOSER TO THE INCOMING DRIER AIR AND SEE A QUICKER IMPROVEMENT THAN AT IWD/ SAW...WHERE A MORE SGNFT UPSLOPE WIND COMPONENT WL ALSO SLOW THE TREND TOWARD VFR. UNDER A TIGHTENING PRES GRADIENT...EXPECT GUSTY NNE WINDS AT ALL 3 SITES TNGT/THU MRNG. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 353 PM EDT WED MAY 22 2013 EXPECT INCREASING NE WINDS UP TO 25-30 KTS UNDER SHARPENING PRES GRADIENT IN ADVANCE OF HI PRES BUILDING TOWARD LAKE SUP THRU TONIGHT. THIS STRENGTHENING FLOW WILL ADVECT DRIER AIR OVER THE LAKE...SO LINGERING FOG SHOULD DISSIPATE THIS EVENING. BASED ON CURRENT VISIBILITY REPORTS/WEBCAM IMAGERY NEAR THE LAKE...OPTED TO CANX GOING DENSE FOG ADVISORIES THAT WERE SET TO EXPIRE AT 21Z. CLOSER APPROACH OF HI PRES/WEAKER PRES GRADIENT WILL RESULT IN SLOWLY DIMINISHING WINDS W TO E ON THU. AS HIGH PRESSURE CONTINUES TO SPREAD ACROSS THE UPPER GREAT LAKES THROUGH THE WEEKEND...EXPECT WINDS LESS THAN 20 KTS ON LAKE SUPERIOR. LIGHTER WINDS WILL CONTINUE INTO EARLY NEXT WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ221-248- 250. && $$ SHORT TERM...KC LONG TERM...JLA AVIATION...KC MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
407 AM EDT WED MAY 22 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 357 PM EDT TUE MAY 21 2013 12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOW MOVING UPR LO OVER ERN SDAKOTA BTWN UPR RDG OVER SCENTRAL CANADA AND A RIDGE OFF THE SE CONUS. BAND OF SHRA/SCT TS THAT IMPACTED THE CWA EARLIER HAS LIFTED TO THE N ALONG WITH RESPONSIBLE SHRTWV...ALLOWING FOR MAINLY DRY WX OVER UPR MI EARLY THIS AFTN. BUT SINCE THE CWA IS N OF SFC WARM FNT IN WI...PLENTY OF LO CLDS LINGER. THERE IS ALSO SOME FOG... MAINLY NEAR THE COOLER GREAT LKS. ANOTHER DISTURBANCE IS ROTATING N THRU IOWA ARND THE CLOSED LO. THE APRCH OF THIS DISTURBANCE HAS RESULTED IN SOME SHRA OVER CENTRAL WI WHERE BREAKS IN THE LO CLDS ALONG AND S OF WARM FNT HAVE LIFTED SB CAPE 500-1000 J/KG PER SPC MESOANALYSIS. MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS TRENDS ASSOCIATED WITH SHRTWV IN IOWA AND THEN APRCH OF MAIN UPR LO. LATE THIS AFTN/TNGT...SHORT RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING SHRA NOW OVER CENTRAL WI DRIFTING ACRS THE WI BORDER BY 21Z AND THEN CONTINUING TO THE NE. RUC FCST SDNGS MODIFIED FOR TEMP/DEWPT OF 68/58 YIELDS SBCAPE UP TO 750 J/KG...SO ADDED MENTION OF TS. RELATIVELY WEAK WINDS SFC-H5 AS WELL AS DEEP MSTR/SKINNY CAPE WITH PERSISTENT LO CLDS LIMITING DIURNAL HEATING INDICATE A LO RISK FOR ANY SVR TS...BUT ANY SHRA COULD RESULT IN SOME HEAVY RA WITH FCST KINX AS HI AS THE UPR 30S. ONCE THE SHRA MOVE FARTHER TO THE NE AND AWAY FM THE SFC HEATING AREA...ONE MIGHT EXPECT THESE SHRA TO DIMINISH THRU THE NGT. BUT FCST AREA OF H85-7 FGEN N OF WARM FNT MIGHT ACT TO SUSTAIN THESE SHRA. WL GO WITH HI CHC-LIKELY POPS THIS EVNG NEAR THE WI BORDER DIMINISHING TO CHCY POPS TO THE NE. SINCE THE LLVL FLOW IS FCST TO BACK MORE TO THE NE FOLLOWING THE PASSAGE OF THIS SHRA AREA...EXPECT COOLER LAKE AIR/SOME FOG TO MOVE BACK INTO THE AREA OVERNGT. WED...AS CLOSED LO TO THE W BEGINS TO SHIFT FASTER TO THE ESE TO SW WI BY 00Z THU...AREA OF LARGER SCALE QVECTOR CNVGC WL IMPACT MAINLY THE AREA NEAR THE WI BORDER BUT WEAKEN WITH TIME AS THE UPR CLO BEGINS TO OPEN. BAND OF RA ACCOMPANYING AXIS OF SHARPER FGEN OVER WRN LK SUP/THE WRN ZNS SHOULD THUS SHIFT SLOWLY TO THE SE THRU THE DAY. ARRIVAL OF DRIER AIR FM THE NW TO THE SE OF EXPANDING HI PRES OVER SCENTRAL CANADA MIGHT START TO DIMINISH THE PCPN OVER THE FAR W LATER IN THE DAY. OTRW...LOWERED FCST HI TEMPS TO ACCOUNT FOR STEADY NE WIND OFF LK SUP AND EXPECTED CLD COVER. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 407 AM EDT WED MAY 22 2013 A CLOSED 500 MB LOW WILL BE IN THE PACIFIC NW WITH A TROUGH OVER THE GREAT LAKES REGION AND A RIDGE ACROSS THE PLAINS 12Z THU. PATTERN CHANGES LITTLE THIS FORECAST PERIOD WITH THE TROUGH OVER THE GREAT LAKES MOVING TO THE EASTERN U.S. 12Z SAT AND THE RIDGE STAYING PUT IN THE PLAINS. LOOKS DRY FOR THIS FORECAST PERIOD WITH COLD TEMPERATURES. THERE WILL BE SOME FROST FOR THU NIGHT AND FRI NIGHT AND PUT IT IN THE WEATHER GRIDS TO HELP WITH THE FIRE WEATHER FORECAST. THE FROST/FREEZE SEASON STARTS AFTER MEMORIAL DAY...BUT WILL MENTION THIS IN THE HWO PRODUCT. WITH THE RIDGE NEARBY AND VERY DRY AND COLD AIR...GOOD RADIATIONAL COOLING CONDITIONS WILL SET UP AND WENT WITH THE COLDEST GUIDANCE I COULD FIND FOR LOW TEMPERATURES WHICH WAS THE ADJMET AND MADE A FEW ADJUSTMENTS FOR COLDER SPOTS. HIGHS ON THU WILL STRUGGLE TO GET TO THE MID 50S. FOR FRI...WENT COLDER FOR HIGHS AS WELL WITH A COLDER START IN THE MORNING AND 850 MB TEMPERATURES WARMING ONLY TO 4C. MIXING THIS DOWN TO THE SFC WOULD GIVE ME HIGHS AROUND 60 AT BEST. THE TEMPERATURES WERE THE MAIN THING THAT I ADJUSTED FOR THIS FORECAST WITH A SLIGHTLY COLDER FORECAST. IN THE EXTENDED...ECMWF AND GFS SHOW A 500 MB RIDGE ACROSS THE PLAINS WITH TROUGHING IN THE PACIFIC NW AND IN NEW ENGLAND 12Z SAT. PATTERN CHANGES VERY LITTLE 12Z SUN THROUGH 12Z TUE. WILL BE FAIRLY DRY THIS FORECAST PERIOD AND QUIET WITH COLDER THAN NORMAL TEMPERATURES WITH A SLOW WARMING TREND THROUGH THE PERIOD. THERE IS A SLIGHT CHANCE FOR PCPN MONDAY NIGHT AND TUESDAY WITH A WARM FRONT SETTING UP TO THE SOUTH...BUT NOT REAL IMPRESSED WITH SEEING MUCH RAIN OUT OF THIS FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1209 AM EDT WED MAY 22 2013 COOL/MOIST AIR UPSLOPING OFF LAKE SUPERIOR WILL LIKELY RESULT IN LIFR CONDITIONS AT KIWD/KCMX/KSAW THRU THE NIGHT. CONDITIONS MAY END UP VLIFR FOR MUCH OF THE NIGHT AT KSAW UNDER A MORE DIRECT LIGHT UPSLOPE FLOW. EXPECT -SHRA/-DZ AT TIMES...ESPECIALLY AT KIWD/KCMX DUE TO AN AREA OF MORE PERSISTENT SYNOPTIC FORCING. THESE MORE PERSISTENT -SHRA SHOULD DRIFT SE AND AFFECT KSAW WED AFTN. THERE IS LIGHT AT THE END OF THE TUNNEL AS LOW LOW PRES THAT HAS PLAGUED THE AREA IN RECENT DAYS WILL CONTINUE TO WEAKEN AND WILL BE SHUNTED SE BY HIGH PRES NOSING S TOWARD THE UPPER LAKES. DRIER AIR ASSOCIATED WITH THE HIGH WILL LEAD TO STEADILY IMPROVING CONDITIONS FROM N TO S WED AFTN/EVENING. KIWD/KCMX SHOULD BREAK OUT TO VFR IN THE EVENING...PERHAPS SOONER...ESPECIALLY AT KCMX. IT MAY NOT BE UNTIL NEAR THE END OF THIS FCST PERIOD THAT KSAW IMPROVES TO VFR. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 407 AM EDT WED MAY 22 2013 ARRIVAL OF DRIER AIR FROM THE NW TODAY WILL SLOWLY DIMINISH THE FOG ON THE GREAT LAKES. GUSTY NORTHERLY WINDS ARE EXPECTED BEHIND THE LOW PRESSURE SYSTEM TONIGHT INTO THURSDAY...BUT LINGERING WARM AIR ALOFT SHOULD KEEP WINDS IN 20-25KT RANGE. THEN...A HIGH PRESSURE RIDGE BUILDING SOUTHEAST OVER THE UPPER GREAT LAKES FOR THURSDAY NIGHT THROUGH THE WEEKEND WILL BRING LIGHT WINDS TO LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ249>251- 266-267. DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR LSZ162-240>242-245>248-263-265. DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LSZ243-244- 264. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR LMZ221-248. DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ250. && $$ SHORT TERM...KC LONG TERM...07 AVIATION...ROLFSON MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1210 AM EDT WED MAY 22 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 357 PM EDT TUE MAY 21 2013 12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOW MOVING UPR LO OVER ERN SDAKOTA BTWN UPR RDG OVER SCENTRAL CANADA AND A RIDGE OFF THE SE CONUS. BAND OF SHRA/SCT TS THAT IMPACTED THE CWA EARLIER HAS LIFTED TO THE N ALONG WITH RESPONSIBLE SHRTWV...ALLOWING FOR MAINLY DRY WX OVER UPR MI EARLY THIS AFTN. BUT SINCE THE CWA IS N OF SFC WARM FNT IN WI...PLENTY OF LO CLDS LINGER. THERE IS ALSO SOME FOG... MAINLY NEAR THE COOLER GREAT LKS. ANOTHER DISTURBANCE IS ROTATING N THRU IOWA ARND THE CLOSED LO. THE APRCH OF THIS DISTURBANCE HAS RESULTED IN SOME SHRA OVER CENTRAL WI WHERE BREAKS IN THE LO CLDS ALONG AND S OF WARM FNT HAVE LIFTED SB CAPE 500-1000 J/KG PER SPC MESOANALYSIS. MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS TRENDS ASSOCIATED WITH SHRTWV IN IOWA AND THEN APRCH OF MAIN UPR LO. LATE THIS AFTN/TNGT...SHORT RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING SHRA NOW OVER CENTRAL WI DRIFTING ACRS THE WI BORDER BY 21Z AND THEN CONTINUING TO THE NE. RUC FCST SDNGS MODIFIED FOR TEMP/DEWPT OF 68/58 YIELDS SBCAPE UP TO 750 J/KG...SO ADDED MENTION OF TS. RELATIVELY WEAK WINDS SFC-H5 AS WELL AS DEEP MSTR/SKINNY CAPE WITH PERSISTENT LO CLDS LIMITING DIURNAL HEATING INDICATE A LO RISK FOR ANY SVR TS...BUT ANY SHRA COULD RESULT IN SOME HEAVY RA WITH FCST KINX AS HI AS THE UPR 30S. ONCE THE SHRA MOVE FARTHER TO THE NE AND AWAY FM THE SFC HEATING AREA...ONE MIGHT EXPECT THESE SHRA TO DIMINISH THRU THE NGT. BUT FCST AREA OF H85-7 FGEN N OF WARM FNT MIGHT ACT TO SUSTAIN THESE SHRA. WL GO WITH HI CHC-LIKELY POPS THIS EVNG NEAR THE WI BORDER DIMINISHING TO CHCY POPS TO THE NE. SINCE THE LLVL FLOW IS FCST TO BACK MORE TO THE NE FOLLOWING THE PASSAGE OF THIS SHRA AREA...EXPECT COOLER LAKE AIR/SOME FOG TO MOVE BACK INTO THE AREA OVERNGT. WED...AS CLOSED LO TO THE W BEGINS TO SHIFT FASTER TO THE ESE TO SW WI BY 00Z THU...AREA OF LARGER SCALE QVECTOR CNVGC WL IMPACT MAINLY THE AREA NEAR THE WI BORDER BUT WEAKEN WITH TIME AS THE UPR CLO BEGINS TO OPEN. BAND OF RA ACCOMPANYING AXIS OF SHARPER FGEN OVER WRN LK SUP/THE WRN ZNS SHOULD THUS SHIFT SLOWLY TO THE SE THRU THE DAY. ARRIVAL OF DRIER AIR FM THE NW TO THE SE OF EXPANDING HI PRES OVER SCENTRAL CANADA MIGHT START TO DIMINISH THE PCPN OVER THE FAR W LATER IN THE DAY. OTRW...LOWERED FCST HI TEMPS TO ACCOUNT FOR STEADY NE WIND OFF LK SUP AND EXPECTED CLD COVER. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 357 PM EDT TUE MAY 21 2013 AFTER A WET START TO THE WEEK...THE LONG TERM PERIOD LOOKS TO BE FAIRLY DRY AS CANADIAN HIGH PRESSURE SLIDES THROUGH THE UPPER GREAT LAKES REGION. FIRST...THE UPPER TROUGH THAT HAS BEEN INFLUENCING THE WEATHER FOR THE START OF THE WORK WEEK WILL BE SITUATED OVER WISCONSIN AND IOWA AND SHIFTING EAST THROUGH THE GREAT LAKES REGION ON WEDNESDAY NIGHT. MEANWHILE...THE SURFACE LOW WILL BE LOCATED OVER LOWER MICHIGAN AT 00Z THURSDAY AND BEGIN TO MOVE UP THE ST LAWRENCE SEAWAY WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE INTENSIFIES THE LOW. AS THIS OCCURS...HIGH PRESSURE ORIGINATING FROM NORTH CENTRAL CANADA WILL BE MOVING A RIDGE INTO THE UPPER MISSISSIPPI VALLEY ON WEDNESDAY NIGHT AND THE UPPER GREAT LAKES ON THURSDAY. WITH THE UPPER TROUGH AND CLOSE PROXIMITY OF THE LOW...THERE WILL STILL BE DEEPER MOISTURE AND 850-700MB Q-VECTOR CONVERGENCE OVER THE SOUTHEAST HALF OF THE CWA. IN ADDITION...WITH THE INCREASING NORTHERLY 850-700MB FLOW OVER THE AREA MODELS ARE CONSISTENT ON AN AREA OF FGEN SETUP FROM IRONWOOD THROUGH EASTERN LAKE SUPERIOR AT 00Z THURSDAY. THEN AS THE LOW SHIFTS EAST...THE FGEN WILL SLIDE SOUTHEAST THROUGH THE NIGHT AND LIKELY EXIT THE MOST IF NOT ALL OF THE CWA BY 12Z THURSDAY. AT THIS POINT...THINKING THAT THE MOVEMENT OF THE PRECIPITATION SHOULD KEEP AMOUNTS UNDER A QUARTER OF AN INCH. CANADIAN HIGH PRESSURE THEN BECOMES THE DOMINATING FEATURE FOR THE REST OF THE PERIOD...AS THE AREA IS UNDER NORTHWEST FLOW ALOFT. THIS DRY CANADIAN AIR AND COOLER NORTHERLY LOW LEVEL WINDS WILL LEAD TO NICE BUT SLIGHTLY COOLER THAN NORMAL START TO THE MEMORIAL DAY WEEKEND. THE STRONGEST NORTHERLY FLOW OFF LAKE SUPERIOR WILL BE ON THURSDAY WITH THE CLOSER PROXIMITY OF THE EXITING LOW. THIS WILL KEEP TEMPERATURES COOLER THAN MOST OF THE DAYS...WITH HIGHS IN THE UPPER 40S NEAR LAKE SUPERIOR AND IN THE 50S INLAND. FRIDAY-SUNDAY WILL BE DOMINATED BY LAKE BREEZES EACH DAY...WITH THE WARMEST TEMPERATURES OVER THE INTERIOR LOCATIONS /60S/. THERE ARE HINTS OF A COUPLE WEAK SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT FRI-SUN...BUT WILL THE DRY AIR IN PLACE...WOULDN/T EXPECT MUCH FOR PRECIPITATION CHANCES. UNDER THE HIGH PRESSURE RIDGE ON THURSDAY NIGHT...EXPECT TO SEE SOME SUB FREEZING LOWS OVER THE INTERIOR PORTIONS OF UPPER MICHIGAN. PWAT VALUES AROUND 40 PERCENT OF NORMAL AND LIGHT WINDS WOULD BE FAVORABLE WELL BELOW NORMAL LOWS. MAV/MET GUIDANCE PICKING UP ON THIS IDEA WITH LOWS BETWEEN 25-30 OVER THE WEST AND THAT SEEMS FAIRLY REASONABLE. HAVE TRENDED THAT DIRECTION AND LOWERED TEMPS OVER THE WEST AROUND 5 DEGREES. FROST/FREEZE HEADLINES DON/T START UNTIL MEMORIAL DAY...SO THERE WON/T BE ANY HEADLINES...BUT ANYONE THAT HAS PLANTED EARLY WILL NEED TO PREPARE FOR A POTENTIAL FROST/FREEZE. UPPER RIDGING THAT WILL BE NEARLY STATIONARY JUST EAST OF THE NORTHERN ROCKIES DURING THIS PERIOD WILL BEGIN TO SHIFT EAST ON SUNDAY NIGHT AS THE UPPER TROUGH OVER THE NEW ENGLAND STATES SHIFTS EAST INTO THE ATLANTIC. THIS WILL START A GRADUAL WARMING TREND TOWARDS MEMORIAL DAY AND INTO THE FIRST PART OF NEXT WEEK. IN ADDITION...IT WILL ALSO BRING BETTER OPPORTUNITIES FOR SHORTWAVES TO RIDE OVER THE RIDGE AND INTO THE AREA LATER MONDAY AND MORE LIKELY TOWARDS TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1209 AM EDT WED MAY 22 2013 COOL/MOIST AIR UPSLOPING OFF LAKE SUPERIOR WILL LIKELY RESULT IN LIFR CONDITIONS AT KIWD/KCMX/KSAW THRU THE NIGHT. CONDITIONS MAY END UP VLIFR FOR MUCH OF THE NIGHT AT KSAW UNDER A MORE DIRECT LIGHT UPSLOPE FLOW. EXPECT -SHRA/-DZ AT TIMES...ESPECIALLY AT KIWD/KCMX DUE TO AN AREA OF MORE PERSISTENT SYNOPTIC FORCING. THESE MORE PERSISTENT -SHRA SHOULD DRIFT SE AND AFFECT KSAW WED AFTN. THERE IS LIGHT AT THE END OF THE TUNNEL AS LOW LOW PRES THAT HAS PLAGUED THE AREA IN RECENT DAYS WILL CONTINUE TO WEAKEN AND WILL BE SHUNTED SE BY HIGH PRES NOSING S TOWARD THE UPPER LAKES. DRIER AIR ASSOCIATED WITH THE HIGH WILL LEAD TO STEADILY IMPROVING CONDITIONS FROM N TO S WED AFTN/EVENING. KIWD/KCMX SHOULD BREAK OUT TO VFR IN THE EVENING...PERHAPS SOONER...ESPECIALLY AT KCMX. IT MAY NOT BE UNTIL NEAR THE END OF THIS FCST PERIOD THAT KSAW IMPROVES TO VFR. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 357 PM EDT TUE MAY 21 2013 GIVEN WIDESPREAD AREA OF RA THAT IMPACTED MUCH OF LAKE SUP INTO THIS MORNING...SOME RECENT SHIP OBS THAT INDICATED LO VISIBILITY...AND SHALLOW COOL AIRMASS OVER THE LAKE...OPTED TO EXTENDED DENSE FOG ADVY THRU TONIGHT. ARRIVAL OF DRIER AIR FROM THE NW ON WED WILL SLOWLY DIMINISH THE FOG. OTHERWISE...NE WINDS UP TO 25 TO 30 KTS... WITH SOME GALE FORCE GUSTS AT THE HIER PLATFORMS...WILL CONTINUE STRONGEST OVER WESTERN LAKE SUP WHERE TERRAIN FUNNELING WILL ENHANCE THE WIND SPEEDS. GUSTY NORTHERLY WINDS ARE EXPECTED BEHIND THE LOW PRESSURE SYSTEM ON WEDNESDAY NIGHT INTO THURSDAY...BUT LINGERING WARM AIR ALOFT SHOULD KEEP WINDS IN 20-25KT RANGE. THEN...A HIGH PRESSURE RIDGE BUILDING SOUTHEAST OVER THE UPPER GREAT LAKES FOR THURSDAY NIGHT THROUGH THE WEEKEND WILL BRING LIGHT WINDS TO LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 6 AM EDT /5 AM CDT/ EARLY THIS MORNING FOR LSZ162-243>249-263>267. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LMZ221-248- 250. && $$ SHORT TERM...KC LONG TERM...SRF AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1248 PM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 625 AM CDT WED MAY 22 2013 AS DISCUSSED EARLIER...ENDED UP MAKING A FEW ADJUSTMENTS TO VERY SHORT TERM GRIDS BASED ON LATEST RADAR TRENDS...AND WITH SUPPORT FROM THE LATEST RAP13/HRRR QPF/REFLECTIVITY. ALTHOUGH CANNOT RULE OUT A FEW SPOTS REPORTING LIGHT MEASURABLE RAIN WITH THIS ACTIVITY...ESPECIALLY IN THE NANCE/POLK COUNTY AREA...THINK THAT NON-MEASURABLE SPRINKLES WILL BE THE DOMINANT STORY FOR MOST OF THE AFFECTED AREA...AND THUS LEFT OUT A MEASURABLE POP. HOWEVER...BEEFED UP SPRINKLE WORDING TO WIDESPREAD IN SEVERAL FAR NORTHEAST COUNTIES THROUGH NOON 17Z...AND EXPANDED AN ISOLATED SPRINKLE MENTION AS FAR SOUTH AS A LOUP CITY-GENEVA LINE. IT MAY TURN OUT THAT THIS LIGHT PRECIP MAY BE OUT OF THE PICTURE WELL BEFORE NOON...BUT GIVEN THE VERY SLOW MOVING NATURE OF THE PARENT MID LEVEL LOW TO THE EAST ANYTHING IS POSSIBLE. ALSO BEEFED UP SKY COVER PERCENTAGES FROM MOSTLY CLOUDY TO OUTRIGHT CLOUDY ACROSS ROUGHLY THE NORTHEAST 1/2 OF THE CWA THROUGH MID-DAY...WHILE LEAVING A MORE OPTIMISTIC TREND IN PLACE FARTHER SOUTHWEST. THE LATEST HRRR IS NOW SPORTING A ROUGHLY 20 DEGREE HIGH-TEMP GRADIENT ACROSS THE CWA THIS AFTERNOON FROM ONLY LOW-MID 50S NORTHEAST TO MID 70S SOUTHWEST. OTHER SHORT TERM MODELS SUCH AS THE RAP13 ARE NOT AS COOL IN THE NORTHEAST AS THE HRRR...AND THUS WILL RESIST THE URGE TO MODIFY AFTERNOON HIGHS AT THIS TIME...BUT FOR SURE ITS POSSIBLE THAT SOME NORTHEAST AREAS COULD STRUGGLE TO REACH THE MID-UPPER 50S AND NEXT SHIFT WILL HAVE MONITOR TRENDS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 509 AM CDT WED MAY 22 2013 WHILE THERE IS CERTAINLY NO HIGH-IMPACT WEATHER DURING THE NEXT 24 HOURS...THERE ARE AT LEAST A FEW TRICKY ELEMENTS AT HAND...INCLUDING THE EXTENT OF LOW STRATUS AND ITS POSSIBLE INFLUENCE ON A FAIRLY DECENT SOUTHWEST-NORTHEAST TEMP GRADIENT...AND ALSO THE EXTENT OF SPRINKLES/LIGHT RAIN SHOWERS MAINLY THIS MORNING IN THE NORTHEAST. 08Z OBJECTIVE SURFACE ANALYSIS REVEALS NO MAJOR FEATURES ACROSS THE CENTRAL PLAINS...WITH THE CWA POSITIONED BETWEEN A MODEST 1004 MILLIBAR LOW OVER EASTERN IA...AND A 1014MB HIGH OVER THE NEB PANHANDLE...A SOUTHWARD EXTENSION OF A STRONGER...BROADER HIGH WELL TO THE NORTH IN CANADA. WITHIN THE MODEST PRESSURE GRADIENT BETWEEN THESE FEATURES...A FAIRLY STEADY NORTH-NORTHWEST BREEZE OF 10-15 MPH HAS PREVAILED THROUGH THE NIGH IN MOST AREAS...WITH OCCASIONAL GUSTS OVER 20 MPH. TEMPERATURES WILL START OUT THE MORNING SEASONABLY COOL...WITH EVENTUAL LOWS AIMED INTO THE MID- UPPER 40S ALL AREAS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA FEATURES A CLOSED 500MB LOW DRIFTING SLOWLY EAST...CENTERED NEAR THE IA/SD/NEB BORDER...AND A FAIRLY SHARP MID LEVEL TROUGH AXIS THEN TRAILING SOUTH-SOUTHEAST INTO THE MID-SOUTH STATES. OFF TO THE WEST OF THE LOCAL AREA...A LOW AMPLITUDE MID LEVEL RIDGE IS ALIGNED NORTH-SOUTH THROUGH THE ROCKIES...WITH A FAIRLY VIGOROUS...EXPANSIVE CLOSED LOW SPINNING OVER THE PACIFIC NORTHWEST. WHILE IT HAS TAKEN ITS TIME FORMING...11-3.9 MICRON SATELLITE IMAGERY AND AUTOMATED OBS HAVE FINALLY REVEALED THE FORMATION OF FAIRLY WIDESPREAD LOW STRATUS MAINLY IN THE 1500-2500 FT RANGE OVER MUCH OF THE CWA...ALTHOUGH SOME BREAKS IN THE CLOUDS DO STILL EXIST. ALSO JUST WITHIN THE PAST 90 MINUTES OR SO...AN INCREASING FLARE-UP OF LIGHT RAIN/SPRINKLES HAS TAKEN PLACE MAINLY OVER THE FAR NORTHERN/NORTHEAST CWA...WITH UPSTREAM OBS AT PLACES SUCH AS ONEILL AND ALBION CONFIRMING AT LEAST TRACE AMOUNTS ARE FALLING. TODAY...THE MAIN STORY ALOFT INVOLVES THE CONTINUED SLOW DEPARTURE OF THE CLOSED MID LEVEL LOW...WITH THE CENTER OF THIS FEATURE PROGGED TO ONLY REACH NORTHEAST IA BY 00Z. AT THE SURFACE...A MODEST PRESSURE GRADIENT WILL REMAIN IN PLACE AS HIGH PRESSURE TO THE NORTH NOSES SOUTHWARD...AND THIS IN COMBINATION WITH MIXING TO AT LEAST 850MB IN MOST AREAS WILL RESULT IN SOMEWHAT BREEZY CONDITIONS ESPECIALLY WITHIN THE NORTHEAST 2/3 OF THE CWA...WITH SUSTAINED NORTHWEST WINDS 15 TO POSSIBLY 20 MPH...AND SOME HIGHER GUSTS. THE REAL CHALLENGE TODAY LIES INITIALLY WITH THE EXTENT AND INTENSITY OF RAINFALL...AND ALSO JUST HOW STUBBORN THE LOW STRATUS DECK WILL BE...AND WHETHER OR NOT IT RETREATS SLOW NORTHEAST DURING THE AFTERNOON. STARTING OUT EARLY THIS MORNING THROUGH MID- DAY...HAVE INTRODUCED A MENTION OF SPRINKLES TO A PREVIOUSLY PRECIP-FREE FORECAST FOR FAR NORTHEAST AREAS MAINLY NORTH OF A GREELEY-POLK LINE...AS DECENT LOW-MID LEVEL SATURATION UP TO AROUND 600MB RESIDES MAINLY IN THIS ZONE AND POINTS NORTHEAST...ASSOCIATED WITH A BATCH OF MID LEVEL MOISTURE FOCUSED IN THE DEFORMATION ZONE ON THE BACK-SIDE OF THE DEPARTING LOW. THE VERY SHORT TERM QUESTION THAT WILL NEED PONDERED OVER THE NEXT FEW HOURS IS WHETHER TO EXPAND THIS SPRINKLE MENTION SOUTHWESTWARD CLOSER TO I-80 PER SUGGESTION OF THE LATEST HRRR REFLECTIVITY PROG...AND ALSO WHETHER TO UP THE ANTE TO A MEASURABLE POP. WILL GIVE IT SOME TIME TO SEE IF AREA OBSERVATIONS SUPPORT A FEW HUNDREDTHS OF ACCUMULATIONS BEFORE POSSIBLY MAKING THIS MOVE. AT ANY RATE...ANY LIGHT RAINFALL IN THE NORTHEAST...ESPECIALLY OF THE POTENTIALLY MEASURABLE VARIETY...IS EXPECTED TO BE OUT OF THE PICTURE BY NOON...AS THE MID LEVELS START TO DRY OUT FROM WEST TO EAST. CLOUD-WISE...HAVE LEANED TOWARD A COMBINATION OF THE NAM AND HRRR...WITH THE EXPECTATION OF A RATHER SHARP SOUTHWEST-NORTHEAST GRADIENT RANGING FROM MOSTLY SUNNY-PARTLY CLOUDY SOUTHWEST TO MOSTLY CLOUDY AT BEST IN THE NORTHEAST. SHAKY CONFIDENCE IN THESE CLOUD DETAILS LEAD TO SOMEWHAT SHAKY CONFIDENCE IN HIGH TEMPS. AT LEAST FOR NOW...NUDGED SOUTHWEST AREAS UP A FEW DEGREES AND NORTHEAST AREAS DOWN A FEW DEGREES VERSUS PREVIOUS...WHILE LEAVING THE CENTRAL RATHER UNCHANGED. AS A RESULT...AM AIMING FROM UPPER 50S-LOW 60S FAR NORTH/NORTHEAST TO MID 60S TRI-CITIES TO MID 70S SOUTHWEST. HOWEVER...AM STARTING TO WONDER IF THE HRRR MIGHT BE ONTO SOMETHING...KEEPING MUCH OF THE NORTHEAST 1/2 OF THE CWA WELL DOWN IN THE MID-50S AT BEST UNDER THE LONGEST-LASTING STRATUS. THIS WILL BEAR WATCHING FOR LATER UPDATES...BUT DON/T WANT TO GO QUITE THIS COOL YET. TURNING TO THE TONIGHT PERIOD...00Z-12Z...CONFIDENCE REMAINS RATHER HIGH IN A LEGITIMATELY DRY NIGHT...WITH THE SOLE POSSIBLE EXCEPTION OF SOME PATCHY LIGHT DRIZZLE IN THE EVENING IN THE NORTH UNDER A LOW STRATUS DECK...BUT THIS SCENARIO IS TOO UNCERTAIN TO INSERT AT THIS TIME. IN THE MID-UPPER LEVELS...THE DEPARTING LOW FINALLY SLIPS FAR ENOUGH EAST TO ALLOW THE RIDGE TO THE WEST TO START BUILDING INTO NEB/KS. ALTHOUGH THERE WILL BE A MODEST NORTHWEST-SOUTHEAST ORIENTED WING OF MID LEVEL MOISTURE ADVECTION/ISENTROPIC LIFT THAT SETS UP FROM SOUTHWEST NEB TO SOUTHEAST KS MAINLY AFTER MIDNIGHT AS EVIDENT ON THE 310K SURFACE...SOUNDINGS SUGGEST THAT LIFT/MOISTURE SHOULD BE INSUFFICIENT FOR PRECIP OVER THE CWA...ALTHOUGH A FEW SHOWERS OR EVEN WEAK STORMS COULD FLARE UP WITHIN A FEW COUNTIES JUST TO THE SOUTH/SOUTHWEST BY SUNRISE. AT THE SURFACE...HIGH PRESSURE WILL CONTINUE OOZING DOWN FROM THE NORTH...KEEPING FAIRLY LIGHT BUT STEADY NORTHERLY BREEZES AROUND 10 MPH IN PLACE. DESPITE THE PRESENCE OF POTENTIALLY DECENT LOW LEVEL SATURATION...THESE BREEZES SHOULD KEEP ANYTHING MORE THAN HAZE/LIGHT FOG AT BAY. THE REAL QUESTION MARK AT THIS POINT TONIGHT AGAIN LIES WITH LOW STRATUS TRENDS. WHILE THE PREVIOUS FORECAST HAD NO WORSE THAN PARTLY CLOUDY SKIES...THE LATEST NAM RUNS AND ASSOCIATED MET GUIDANCE FAIRLY AGGRESSIVELY BRING A BATCH OF LOW STRATUS BACK SOUTHWARD ACROSS MOST OF THE CWA AS THE NIGHT WEARS ON...WITH THIS ESPECIALLY EVIDENT AT 900MB. FOR NOW...HAVE STARTED AN UPWARD TREND IN SKY COVER...BUT VERY WELL MAY NOT BE HIGH ENOUGH ESPECIALLY POST-MIDNIGHT. EVEN IF STRATUS DOES END UP BEING MORE WIDESPREAD THAN CURRENTLY SUGGESTED...CONFIDENCE IS DECENT THAT LOW TEMPS WILL END UP SIMILAR TO THOSE OF THIS MORNING...AND USED A BLEND OF MET/MAV GUIDANCE...AIMING FOR ANOTHER COOL ONE WITH MID 40S MOST SPOTS. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 509 AM CDT WED MAY 22 2013 MODELS ARE IN GOOD AGREEMENT TRANSITIONING A RIDGE OF HIGH PRESSURE ACROSS THE PLAINS ON THURSDAY IN WAKE OF THE DEPARTING UPPER LEVEL LOW. WHILE HEIGHTS ALOFT WILL BE RISING...EXPECT ONLY A MODESTLY WARMER AFTERNOON ON THURSDAY AS 850MB TEMPS ARE EXPECTED TO ONLY REBOUND A COUPLE OF DEGREES AND PLENTY OF CLOUD COVER IS EXPECTED IN EASTERLY UPSLOPE FLOW. AS THE WINDS SHIFT MORE SOUTHEASTERLY THURSDAY NIGHT AND FRIDAY...EXPECT ADDITIONAL MOISTURE TO SURGE NORTHWARD...AND FOR INCREASING INSTABILITY ACROSS THE REGION. THIS BUILDING INSTABILITY COMBINED WITH SOME FORCING FROM THE LOW LEVEL JET...WILL LIKELY RESULT IN A CHANCE OF THUNDERSTORMS THURSDAY NIGHT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA...WHICH WILL BE IN CLOSER PROXIMITY TO THE JET. WITH THE NOSE OF THE NOCTURNAL JET MORE FOCUSED ACROSS THE HEART OF LOCAL AREA FRIDAY AND FRIDAY NIGHT...CANNOT RULE OUT ADDITIONAL ELEVATED SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCES FOR PRECIPITATION COMING DURING THE LATE EVENING AND OVERNIGHT HOURS. THEREAFTER THE MID LEVEL CAP IS EXPECTED TO WEAKEN SUBSTANTIALLY BY SATURDAY AFTERNOON... AND WITH SEVERAL THOUSAND JOULES OF CAPE TO WORK WITH THROUGH THE REMAINDER OF THE LONG TERM PERIODS...WILL LIKELY SEE THUNDERSTORMS AROUND EACH DAY AS PERIODIC VORTICITY MAXIMA EJECT OUT OF THE LONGWAVE TROUGH ACROSS THE WEST COAST. ADDITIONALLY...WITH THESE SUBSTANTIAL CAPE VALUES AND MARGINALLY SUPPORTIVE SHEAR PROFILES...WILL HAVE THE POTENTIAL FOR SOME SEVERE THUNDERSTORMS DEVELOP FROM TIME TO TIME SATURDAY ONWARD...WITH LARGE HAIL AND STRONG THUNDERSTORM WIND GUSTS BEING THE PRIMARY THREATS. TEMPERATURES THROUGH THE PERIOD ARE NOT EXPECTED TO FLUCTUATE A WHOLE LOT AS THERE WILL BE LITTLE CHANGE IN THE UNDERLYING AIRMASS SATURDAY ONWARD...WITH LOWER TO MIDDLE 80S EXPECTED EACH AFTERNOON AND LOWER 60S EXPECTED AT NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1248 PM CDT WED MAY 22 2013 MVFR CONDITIONS FORECAST THROUGH 20Z...VFR 20-02Z...THEN MVFR CONDITIONS 02-15Z. AS OF MIDDAY A STRATUS DECK...WITH A CEILING NEAR 2000FT AGL...PERSISTS AT KGRI. THIS CEILING IS EXPECTED TO CONTINUE THROUGH ANOTHER COUPLE HOURS...BUT IS THEN EXPECTED TO SCATTER OUT BY MID AFTERNOON...THUS THE VFR FORECAST BEGINNING 20Z. VFR CONDITIONS ARE THEN FORECAST THROUGH THIS EVENING...HOWEVER GUIDANCE SUGGESTS AN MVFR DECK WILL ONCE AGAIN INFILTRATE THE AREA THIS EVENING AND INTO THE OVERNIGHT HOURS. IT IS WORTH NOTING THAT SOME GUIDANCE SUGGESTS IFR CEILINGS...OR LOWER...WILL BE REALIZED TONIGHT THROUGH EARLY THURSDAY MORNING...BUT AT THIS TIME CONFIDENCE IS NOT HIGH ENOUGH TO INSERT SUCH CONDITIONS IN THE TAF. FUTURE SHIFTS WILL WANT TO CONTINUE MONITORING FOR THE POSSIBLE INSERTION OF A LOWER CEILING IN FUTURE TAFS. WHAT CEILING DOES DEVELOP OVERNIGHT TONIGHT SHOULD SCATTER OUT POST- SUNRISE THURSDAY. THE SURFACE WIND WILL TRANSITION FROM THE NORTHWEST TO MORE OF A NORTH/NORTHEAST DIRECTION THROUGH THE NEXT 24 HOURS...SUSTAINED AT AROUND 14KTS AND GUSTING NEAR 20KTS THROUGH THIS EVENING. VISIBILITY RESTRICTION IS NOT CURRENTLY EXPECTED AT KGRI THROUGH THE NEXT 24 HOURS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...PFANNKUCH LONG TERM...SAR AVIATION...BRYANT/BRUM
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
950 AM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 949 AM CDT WED MAY 22 2013 UPDATED THE FORECAST FOR TRENDS IN CLOUD COVER AND PRECIPITATION. THE SURFACE LOW WHICH HAS THE MOISTURE ROTATING AROUND IT IS NOW OVER NORTHEAST IOWA AS OF 14Z...WHILE HIGH PRESSURE BUILDS INTO THE PANHANDLE AND WESTERN NEBRASKA. THE CLOUD COVER WAS STARTING TO BREAK UP THIS MORNING...MAINLY OVER THE SOUTHWEST PARTS OF THE FORECAST AREA. THERE IS A NARROW BAND FROM APPROXIMATELY KOGA TO KCDR THAT MAY PERSIST A BIT LONGER...BUT EXPECTING THIS AREA TO MIX OUT AND DISSIPATE BY THE NOON HOUR. GOING FURTHER EAST...THE CLOUDS WILL LIKELY PERSIST THROUGH MUCH OF THE DAY...OR AT LEAST THROUGH MID AFTERNOON AS A THICKER LAYER OF MOISTURE WILL REMAIN. THE SHOWERS HAVE DECREASED IN AREA AND INTENSITY BY LATE THIS MORNING...WITH THE STRONGER ECHOES NOW OVER EASTERN NEBRASKA AND EASTERN SOUTH DAKOTA...CLOSER TO THE SURFACE LOW. WILL KEEP MENTION OF SHOWERS AND SPRINKLES ACROSS NORTH CENTRAL AND CENTRAL NEBRASKA THROUGH THE MORNING...THEN DRY CONDITIONS EXPECTED FOR THE AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT WED MAY 22 2013 WRAP AROUND CLOUDINESS WILL CONTINUE TODAY ACROSS NRN NEB. THE LIGHT RAIN SHOULD END BY NOON. THERE IS ONE MORE IMPULSE ACROSS ERN SD WHICH WILL DROP SOUTH BEFORE THE SFC LOW DRIFTS EAST INTO THE MIDWEST THIS AFTERNOON. THIS LEAVES MUCH OF THE SRN HALF OF THE FCST AREA IN PARTLY CLOUDY SKIES WITH HIGHS IN THE 60S WHILE OVERCAST SKIES KEEP THE NORTH IN THE 50S. TONIGHT...AN INVERTED SFC LOW PRESSURE TROF WILL SHARPEN UP ACROSS THE NRN AND CNTL ROCKIES. THIS WILL SET UP A BROAD BELT OF EASTERLIES ACROSS THE FCST AREA WHICH COULD TRAP LOW LEVEL MOISTURE AND PRODUCE UPSLOPE FOG AND STRATUS ACROSS WRN NEB. PRESUMABLY...DRY AIR COULD MOVE INTO NCNTL NEB CLEARING SKIES THERE. GIVEN THE POOR MODEL PERFORMANCE OF THE NAM IN THESE TYPES OF SITUATIONS...THE RAP MODEL MIGHT BE THE BEST HANDLE FOR TONIGHTS SKY FORECAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 345 AM CDT WED MAY 22 2013 SFC HIGH PRESSURE WILL MOVE EAST OF THE REGION THURSDAY...WITH EAST TO SOUTHEAST WINDS KEEPING CONDITIONS RATHER COOL...WITH HIGHS IN THE 60S TO PERHAPS 70 IN A FEW LOCALS. INCREASING LOW LEVEL MOISTURE COULD LEAD TO SOME STRATUS DEVELOPMENT...ESPECIALLY ACROSS SOUTHWEST NEB AND THE PANHANDLE...WHICH COULD HOLD HIGHS DOWN FURTHER. A SOUTHERLY LLJ CRACKS UP TO AROUND 45 KTS...ADVECTING MORE MOISTURE AND BETTER CHANCES FOR STRATUS CLOUDS INTO THE AREA. WILL MAINTAIN A SLIGHT CHANCE FOR SHOWERS/TSTMS ACROSS SOUTHWEST NEBRASKA...WHERE WARM AIR ADVECTION WILL BE MAXIMIZED. FRIDAY THROUGH TUESDAY APPEARS TO BE QUITE ACTIVE IN TERMS OF CONVECTIVE POTENTIAL. A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL BECOME ANCHORED ACROSS THE PACIFIC NORTHWEST...PROVIDING A SOUTHWEST FLOW ALOFT ACROSS THE CENTRAL CONUS. THIS FLOW DOESN/T APPEAR OVERLY STRONG...BUT ADEQUATE ENOUGH TO SUPPORT SOME SEVERE TSTM POTENTIAL FROM TIME TO TIME. MEANWHILE...PLENTY OF LOW LEVEL MOISTURE AND STEEP MID LEVEL LAPSE RATES...WILL RESULT IN STRONG INSTABILITY DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS THAT A LEEWARD TROUGH/DRY LINE WILL BE ESTABLISHED EACH AFTERNOON ACROSS WESTERN NEB/KS...AND COULD SERVE AS A FOCUS FOR CONVECTIVE INITIATION AS SHORTWAVE TROUGHS EJECT EASTWARD FROM THE WESTERN UPPER LOW. OF COURSE TIMING OF THESE TROUGHS WILL BE A FACTOR...AND LATER FORECASTS WILL REFINE THE TIMING AND INTENSITY OF ANY TSTMS. TEMPERATURES THROUGH THE PERIOD COULD BE A CHALLENGE...ESPECIALLY HIGH TEMPERATURES...AS POTENTIAL EXISTS FOR QUITE A BIT IN THE WAY OF STRATUS CLOUDS DUE TO INCREASED GULF OF MEXICO MOISTURE...AND ANY CONVECTIVE DEBRIS CLOUDINESS. FOR NOW WILL GO WITH HIGHS MAINLY IN THE LOWER 70S TO LOWER 80S...WITH THE WARMEST READINGS ACROSS THE WESTERN PORTIONS OF THE AREA. LOWS WILL BE MILD...MID 50S TO LOWER 60S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 622 AM CDT WED MAY 22 2013 IFR ACROSS NRN NEB SHOULD IMPROVE TO MVFR THIS MORNING WHILE THE MVFR ALONG I-80 IMPROVES TO VFR. TONIGHT...UPSLOPE EASTERLIES DEVELOP AND MVFR/IFR IS EXPECTED TO REDEVELOP ACROSS WRN NEB PERHAPS AFFECTING THE KLBF TERMINAL. MEANWHILE...THE RAP MODEL SUGGESTS CLEARING ACROSS NERN NEB AND THE KVTN TERMINAL. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BROOKS SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
627 AM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 625 AM CDT WED MAY 22 2013 AS DISCUSSED EARLIER...ENDED UP MAKING A FEW ADJUSTMENTS TO VERY SHORT TERM GRIDS BASED ON LATEST RADAR TRENDS...AND WITH SUPPORT FROM THE LATEST RAP13/HRRR QPF/REFLECTIVITY. ALTHOUGH CANNOT RULE OUT A FEW SPOTS REPORTING LIGHT MEASURABLE RAIN WITH THIS ACTIVITY...ESPECIALLY IN THE NANCE/POLK COUNTY AREA...THINK THAT NON-MEASURABLE SPRINKLES WILL BE THE DOMINANT STORY FOR MOST OF THE AFFECTED AREA...AND THUS LEFT OUT A MEASURABLE POP. HOWEVER...BEEFED UP SPRINKLE WORDING TO WIDESPREAD IN SEVERAL FAR NORTHEAST COUNTIES THROUGH NOON 17Z...AND EXPANDED AN ISOLATED SPRINKLE MENTION AS FAR SOUTH AS A LOUP CITY-GENEVA LINE. IT MAY TURN OUT THAT THIS LIGHT PRECIP MAY BE OUT OF THE PICTURE WELL BEFORE NOON...BUT GIVEN THE VERY SLOW MOVING NATURE OF THE PARENT MID LEVEL LOW TO THE EAST ANYTHING IS POSSIBLE. ALSO BEEFED UP SKY COVER PERCENTAGES FROM MOSTLY CLOUDY TO OUTRIGHT CLOUDY ACROSS ROUGHLY THE NORTHEAST 1/2 OF THE CWA THROUGH MID-DAY...WHILE LEAVING A MORE OPTIMISTIC TREND IN PLACE FARTHER SOUTHWEST. THE LATEST HRRR IS NOW SPORTING A ROUGHLY 20 DEGREE HIGH-TEMP GRADIENT ACROSS THE CWA THIS AFTERNOON FROM ONLY LOW-MID 50S NORTHEAST TO MID 70S SOUTHWEST. OTHER SHORT TERM MODELS SUCH AS THE RAP13 ARE NOT AS COOL IN THE NORTHEAST AS THE HRRR...AND THUS WILL RESIST THE URGE TO MODIFY AFTERNOON HIGHS AT THIS TIME...BUT FOR SURE ITS POSSIBLE THAT SOME NORTHEAST AREAS COULD STRUGGLE TO REACH THE MID-UPPER 50S AND NEXT SHIFT WILL HAVE MONITOR TRENDS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 509 AM CDT WED MAY 22 2013 WHILE THERE IS CERTAINLY NO HIGH-IMPACT WEATHER DURING THE NEXT 24 HOURS...THERE ARE AT LEAST A FEW TRICKY ELEMENTS AT HAND...INCLUDING THE EXTENT OF LOW STRATUS AND ITS POSSIBLE INFLUENCE ON A FAIRLY DECENT SOUTHWEST-NORTHEAST TEMP GRADIENT...AND ALSO THE EXTENT OF SPRINKLES/LIGHT RAIN SHOWERS MAINLY THIS MORNING IN THE NORTHEAST. 08Z OBJECTIVE SURFACE ANALYSIS REVEALS NO MAJOR FEATURES ACROSS THE CENTRAL PLAINS...WITH THE CWA POSITIONED BETWEEN A MODEST 1004 MILLIBAR LOW OVER EASTERN IA...AND A 1014MB HIGH OVER THE NEB PANHANDLE...A SOUTHWARD EXTENSION OF A STRONGER...BROADER HIGH WELL TO THE NORTH IN CANADA. WITHIN THE MODEST PRESSURE GRADIENT BETWEEN THESE FEATURES...A FAIRLY STEADY NORTH-NORTHWEST BREEZE OF 10-15 MPH HAS PREVAILED THROUGH THE NIGH IN MOST AREAS...WITH OCCASIONAL GUSTS OVER 20 MPH. TEMPERATURES WILL START OUT THE MORNING SEASONABLY COOL...WITH EVENTUAL LOWS AIMED INTO THE MID- UPPER 40S ALL AREAS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA FEATURES A CLOSED 500MB LOW DRIFTING SLOWLY EAST...CENTERED NEAR THE IA/SD/NEB BORDER...AND A FAIRLY SHARP MID LEVEL TROUGH AXIS THEN TRAILING SOUTH-SOUTHEAST INTO THE MID-SOUTH STATES. OFF TO THE WEST OF THE LOCAL AREA...A LOW AMPLITUDE MID LEVEL RIDGE IS ALIGNED NORTH-SOUTH THROUGH THE ROCKIES...WITH A FAIRLY VIGOROUS...EXPANSIVE CLOSED LOW SPINNING OVER THE PACIFIC NORTHWEST. WHILE IT HAS TAKEN ITS TIME FORMING...11-3.9 MICRON SATELLITE IMAGERY AND AUTOMATED OBS HAVE FINALLY REVEALED THE FORMATION OF FAIRLY WIDESPREAD LOW STRATUS MAINLY IN THE 1500-2500 FT RANGE OVER MUCH OF THE CWA...ALTHOUGH SOME BREAKS IN THE CLOUDS DO STILL EXIST. ALSO JUST WITHIN THE PAST 90 MINUTES OR SO...AN INCREASING FLARE-UP OF LIGHT RAIN/SPRINKLES HAS TAKEN PLACE MAINLY OVER THE FAR NORTHERN/NORTHEAST CWA...WITH UPSTREAM OBS AT PLACES SUCH AS ONEILL AND ALBION CONFIRMING AT LEAST TRACE AMOUNTS ARE FALLING. TODAY...THE MAIN STORY ALOFT INVOLVES THE CONTINUED SLOW DEPARTURE OF THE CLOSED MID LEVEL LOW...WITH THE CENTER OF THIS FEATURE PROGGED TO ONLY REACH NORTHEAST IA BY 00Z. AT THE SURFACE...A MODEST PRESSURE GRADIENT WILL REMAIN IN PLACE AS HIGH PRESSURE TO THE NORTH NOSES SOUTHWARD...AND THIS IN COMBINATION WITH MIXING TO AT LEAST 850MB IN MOST AREAS WILL RESULT IN SOMEWHAT BREEZY CONDITIONS ESPECIALLY WITHIN THE NORTHEAST 2/3 OF THE CWA...WITH SUSTAINED NORTHWEST WINDS 15 TO POSSIBLY 20 MPH...AND SOME HIGHER GUSTS. THE REAL CHALLENGE TODAY LIES INITIALLY WITH THE EXTENT AND INTENSITY OF RAINFALL...AND ALSO JUST HOW STUBBORN THE LOW STRATUS DECK WILL BE...AND WHETHER OR NOT IT RETREATS SLOW NORTHEAST DURING THE AFTERNOON. STARTING OUT EARLY THIS MORNING THROUGH MID- DAY...HAVE INTRODUCED A MENTION OF SPRINKLES TO A PREVIOUSLY PRECIP-FREE FORECAST FOR FAR NORTHEAST AREAS MAINLY NORTH OF A GREELEY-POLK LINE...AS DECENT LOW-MID LEVEL SATURATION UP TO AROUND 600MB RESIDES MAINLY IN THIS ZONE AND POINTS NORTHEAST...ASSOCIATED WITH A BATCH OF MID LEVEL MOISTURE FOCUSED IN THE DEFORMATION ZONE ON THE BACK-SIDE OF THE DEPARTING LOW. THE VERY SHORT TERM QUESTION THAT WILL NEED PONDERED OVER THE NEXT FEW HOURS IS WHETHER TO EXPAND THIS SPRINKLE MENTION SOUTHWESTWARD CLOSER TO I-80 PER SUGGESTION OF THE LATEST HRRR REFLECTITY PROG...AND ALSO WHETHER TO UP THE ANTE TO A MEASURABLE POP. WILL GIVE IT SOME TIME TO SEE IF AREA OBSERVATIONS SUPPORT A FEW HUNDREDTHS OF ACCUMULATIONS BEFORE POSSIBLY MAKING THIS MOVE. AT ANY RATE...ANY LIGHT RAINFALL IN THE NORTHEAST...ESPECIALLY OF THE POTENTIALLY MEASURABLE VARIETY...IS EXPECTED TO BE OUT OF THE PICTURE BY NOON...AS THE MID LEVELS START TO DRY OUT FROM WEST TO EAST. CLOUD-WISE...HAVE LEANED TOWARD A COMBINATION OF THE NAM AND HRRR...WITH THE EXPECTATION OF A RATHER SHARP SOUTHWEST-NORTHEAST GRADIENT RANGING FROM MOSTLY SUNNY-PARTLY CLOUDY SOUTHWEST TO MOSTLY CLOUDY AT BEST IN THE NORTHEAST. SHAKY CONFIDENCE IN THESE CLOUD DETAILS LEAD TO SOMEWHAT SHAKY CONFIDENCE IN HIGH TEMPS. AT LEAST FOR NOW...NUDGED SOUTHWEST AREAS UP A FEW DEGREES AND NORTHEAST AREAS DOWN A FEW DEGREES VERSUS PREVIOUS...WHILE LEAVING THE CENTRAL RATHER UNCHANGED. AS A RESULT...AM AIMING FROM UPPER 50S-LOW 60S FAR NORTH/NORTHEAST TO MID 60S TRI-CITIES TO MID 70S SOUTHWEST. HOWEVER...AM STARTING TO WONDER IF THE HRRR MIGHT BE ONTO SOMETHING...KEEPING MUCH OF THE NORTHEAST 1/2 OF THE CWA WELL DOWN IN THE MID-50S AT BEST UNDER THE LONGEST-LASTING STRATUS. THIS WILL BEAR WATCHING FOR LATER UPDATES...BUT DON/T WANT TO GO QUITE THIS COOL YET. TURNING TO THE TONIGHT PERIOD...00Z-12Z...CONFIDENCE REMAINS RATHER HIGH IN A LEGITIMATELY DRY NIGHT...WITH THE SOLE POSSIBLE EXCEPTION OF SOME PATCHY LIGHT DRIZZLE IN THE EVENING IN THE NORTH UNDER A LOW STRATUS DECK...BUT THIS SCENARIO IS TOO UNCERTAIN TO INSERT AT THIS TIME. IN THE MID-UPPER LEVELS...THE DEPARTING LOW FINALLY SLIPS FAR ENOUGH EAST TO ALLOW THE RIDGE TO THE WEST TO START BUILDING INTO NEB/KS. ALTHOUGH THERE WILL BE A MODEST NORTHWEST-SOUTHEAST ORIENTED WING OF MID LEVEL MOISTURE ADVECTION/ISENTROPIC LIFT THAT SETS UP FROM SOUTHWEST NEB TO SOUTHEAST KS MAINLY AFTER MIDNIGHT AS EVIDENT ON THE 310K SURFACE...SOUNDINGS SUGGEST THAT LIFT/MOISTURE SHOULD BE INSUFFICIENT FOR PRECIP OVER THE CWA...ALTHOUGH A FEW SHOWERS OR EVEN WEAK STORMS COULD FLARE UP WITHIN A FEW COUNTIES JUST TO THE SOUTH/SOUTHWEST BY SUNRISE. AT THE SURFACE...HIGH PRESSURE WILL CONTINUE OOZING DOWN FROM THE NORTH...KEEPING FAIRLY LIGHT BUT STEADY NORTHERLY BREEZES AROUND 10 MPH IN PLACE. DESPITE THE PRESENCE OF POTENTIALLY DECENT LOW LEVEL SATURATION...THESE BREEZES SHOULD KEEP ANYTHING MORE THAN HAZE/LIGHT FOG AT BAY. THE REAL QUESTION MARK AT THIS POINT TONIGHT AGAIN LIES WITH LOW STRATUS TRENDS. WHILE THE PREVIOUS FORECAST HAD NO WORSE THAN PARTLY CLOUDY SKIES...THE LATEST NAM RUNS AND ASSOCIATED MET GUIDANCE FAIRLY AGGRESSIVELY BRING A BATCH OF LOW STRATUS BACK SOUTHWARD ACROSS MOST OF THE CWA AS THE NIGHT WEARS ON...WITH THIS ESPECIALLY EVIDENT AT 900MB. FOR NOW...HAVE STARTED AN UPWARD TREND IN SKY COVER...BUT VERY WELL MAY NOT BE HIGH ENOUGH ESPECIALLY POST-MIDNIGHT. EVEN IF STRATUS DOES END UP BEING MORE WIDESPREAD THAN CURRENTLY SUGGESTED...CONFIDENCE IS DECENT THAT LOW TEMPS WILL END UP SIMILAR TO THOSE OF THIS MORNING...AND USED A BLEND OF MET/MAV GUIDANCE...AIMING FOR ANOTHER COOL ONE WITH MID 40S MOST SPOTS. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 509 AM CDT WED MAY 22 2013 MODELS ARE IN GOOD AGREEMENT TRANSITIONING A RIDGE OF HIGH PRESSURE ACROSS THE PLAINS ON THURSDAY IN WAKE OF THE DEPARTING UPPER LEVEL LOW. WHILE HEIGHTS ALOFT WILL BE RISING...EXPECT ONLY A MODESTLY WARMER AFTERNOON ON THURSDAY AS 850MB TEMPS ARE EXPECTED TO ONLY REBOUND A COUPLE OF DEGREES AND PLENTY OF CLOUD COVER IS EXPECTED IN EASTERLY UPSLOPE FLOW. AS THE WINDS SHIFT MORE SOUTHEASTERLY THURSDAY NIGHT AND FRIDAY...EXPECT ADDITIONAL MOISTURE TO SURGE NORTHWARD...AND FOR INCREASING INSTABILITY ACROSS THE REGION. THIS BUILDING INSTABILITY COMBINED WITH SOME FORCING FROM THE LOW LEVEL JET...WILL LIKELY RESULT IN A CHANCE OF THUNDERSTORMS THURSDAY NIGHT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA...WHICH WILL BE IN CLOSER PROXIMITY TO THE JET. WITH THE NOSE OF THE NOCTURNAL JET MORE FOCUSED ACROSS THE HEART OF LOCAL AREA FRIDAY AND FRIDAY NIGHT...CANNOT RULE OUT ADDITIONAL ELEVATED SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCES FOR PRECIPITATION COMING DURING THE LATE EVENING AND OVERNIGHT HOURS. THEREAFTER THE MID LEVEL CAP IS EXPECTED TO WEAKEN SUBSTANTIALLY BY SATURDAY AFTERNOON... AND WITH SEVERAL THOUSAND JOULES OF CAPE TO WORK WITH THROUGH THE REMAINDER OF THE LONG TERM PERIODS...WILL LIKELY SEE THUNDERSTORMS AROUND EACH DAY AS PERIODIC VORTICITY MAXIMA EJECT OUT OF THE LONGWAVE TROUGH ACROSS THE WEST COAST. ADDITIONALLY...WITH THESE SUBSTANTIAL CAPE VALUES AND MARGINALLY SUPPORTIVE SHEAR PROFILES...WILL HAVE THE POTENTIAL FOR SOME SEVERE THUNDERSTORMS DEVELOP FROM TIME TO TIME SATURDAY ONWARD...WITH LARGE HAIL AND STRONG THUNDERSTORM WIND GUSTS BEING THE PRIMARY THREATS. TEMPERATURES THROUGH THE PERIOD ARE NOT EXPECTED TO FLUCTUATE A WHOLE LOT AS THERE WILL BE LITTLE CHANGE IN THE UNDERLYING AIRMASS SATURDAY ONWARD...WITH LOWER TO MIDDLE 80S EXPECTED EACH AFTERNOON AND LOWER 60S EXPECTED AT NIGHT. && .AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z THURSDAY MORNING) ISSUED AT 625 AM CDT WED MAY 22 2013 ALTHOUGH CONFIDENCE IS HIGH IN VFR VISIBILITY THROUGH THE PERIOD...CEILING TRENDS CONTINUE TO BE TRICKY AS PLENTY OF LOWER STRATUS HANGS AROUND THE AREA ON THE BACK SIDE OF A DEPARTING MID LEVEL LOW. STARTING OFF THROUGH THE MORNING INTO THE MID-AFTERNOON HOURS...HAVE CONTINUED A PREVAILING MVFR CEILING...ALTHOUGH JUST WITHIN THE PAST HOUR CLOUDS AT THE MVFR LEVEL HAVE SCATTERED A BIT...DIMINISHING CONFIDENCE SOMEWHAT AND SUGGESTING THAT MVFR MAY BE MORE OFF-AND-ON. ALSO THIS MORNING...A FEW SPRINKLES CANNOT BE RULED OUT AT KGRI...BUT GIVEN SUCH LOW IMPACT WILL OMIT ANY PRECIP MENTION. THROUGH THE LATE AFTERNOON AND EVENING HOURS...KEPT TREND FROM PREVIOUS FORECAST BY RAISING PREVAILING CEILING TO LOW-END VFR. HOWEVER...CONFIDENCE IN THE DETAILS REALLY DECREASES BY THE LAST 6 HOURS OR SO LATE TONIGHT...AS SOME MODELS/GUIDANCE SUGGEST A LOW-MVFR AND POSSIBLY EVEN IFR DECK COULD MATERIALIZE...WHILE OTHER MODELS KEEP CEILING VFR. AS A COMPROMISE BETWEEN THE WIDE POSSIBILITIES AT THIS TIME RANGE...WILL INTRODUCE A SCATTERED LOW-END MVFR CLOUD GROUP. WIND-WISE...A STEADY NORTH-NORTHWEST BREEZE WILL PREVAIL MUCH OF THE DAY WITH GUST POTENTIAL TO AROUND 22KT...BEFORE SLACKENING THIS EVENING AND AVERAGING UNDER 10KT OVERNIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...PFANNKUCH LONG TERM...SAR AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
625 AM CDT WED MAY 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT WED MAY 22 2013 WRAP AROUND CLOUDINESS WILL CONTINUE TODAY ACROSS NRN NEB. THE LIGHT RAIN SHOULD END BY NOON. THERE IS ONE MORE IMPULSE ACROSS ERN SD WHICH WILL DROP SOUTH BEFORE THE SFC LOW DRIFTS EAST INTO THE MIDWEST THIS AFTERNOON. THIS LEAVES MUCH OF THE SRN HALF OF THE FCST AREA IN PARTLY CLOUDY SKIES WITH HIGHS IN THE 60S WHILE OVERCAST SKIES KEEP THE NORTH IN THE 50S. TONIGHT...AN INVERTED SFC LOW PRESSURE TROF WILL SHARPEN UP ACROSS THE NRN AND CNTL ROCKIES. THIS WILL SET UP A BROAD BELT OF EASTERLIES ACROSS THE FCST AREA WHICH COULD TRAP LOW LEVEL MOISTURE AND PRODUCE UPSLOPE FOG AND STRATUS ACROSS WRN NEB. PRESUMABLY...DRY AIR COULD MOVE INTO NCNTL NEB CLEARING SKIES THERE. GIVEN THE POOR MODEL PERFORMANCE OF THE NAM IN THESE TYPES OF SITUATIONS...THE RAP MODEL MIGHT BE THE BEST HANDLE FOR TONIGHTS SKY FORECAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 345 AM CDT WED MAY 22 2013 SFC HIGH PRESSURE WILL MOVE EAST OF THE REGION THURSDAY...WITH EAST TO SOUTHEAST WINDS KEEPING CONDITIONS RATHER COOL...WITH HIGHS IN THE 60S TO PERHAPS 70 IN A FEW LOCALS. INCREASING LOW LEVEL MOISTURE COULD LEAD TO SOME STRATUS DEVELOPMENT...ESPECIALLY ACROSS SOUTHWEST NEB AND THE PANHANDLE...WHICH COULD HOLD HIGHS DOWN FURTHER. A SOUTHERLY LLJ CRACKS UP TO AROUND 45 KTS...ADVECTING MORE MOISTURE AND BETTER CHANCES FOR STRATUS CLOUDS INTO THE AREA. WILL MAINTAIN A SLIGHT CHANCE FOR SHOWERS/TSTMS ACROSS SOUTHWEST NEBRASKA...WHERE WARM AIR ADVECTION WILL BE MAXIMIZED. FRIDAY THROUGH TUESDAY APPEARS TO BE QUITE ACTIVE IN TERMS OF CONVECTIVE POTENTIAL. A LARGE UPPER LEVEL LOW PRESSURE SYSTEM WILL BECOME ANCHORED ACROSS THE PACIFIC NORTHWEST...PROVIDING A SOUTHWEST FLOW ALOFT ACROSS THE CENTRAL CONUS. THIS FLOW DOESN/T APPEAR OVERLY STRONG...BUT ADEQUATE ENOUGH TO SUPPORT SOME SEVERE TSTM POTENTIAL FROM TIME TO TIME. MEANWHILE...PLENTY OF LOW LEVEL MOISTURE AND STEEP MID LEVEL LAPSE RATES...WILL RESULT IN STRONG INSTABILITY DURING THE AFTERNOON AND EVENING HOURS. IT APPEARS THAT A LEEWARD TROUGH/DRY LINE WILL BE ESTABLISHED EACH AFTERNOON ACROSS WESTERN NEB/KS...AND COULD SERVE AS A FOCUS FOR CONVECTIVE INITIATION AS SHORTWAVE TROUGHS EJECT EASTWARD FROM THE WESTERN UPPER LOW. OF COURSE TIMING OF THESE TROUGHS WILL BE A FACTOR...AND LATER FORECASTS WILL REFINE THE TIMING AND INTENSITY OF ANY TSTMS. TEMPERATURES THROUGH THE PERIOD COULD BE A CHALLENGE...ESPECIALLY HIGH TEMPERATURES...AS POTENTIAL EXISTS FOR QUITE A BIT IN THE WAY OF STRATUS CLOUDS DUE TO INCREASED GULF OF MEXICO MOISTURE...AND ANY CONVECTIVE DEBRIS CLOUDINESS. FOR NOW WILL GO WITH HIGHS MAINLY IN THE LOWER 70S TO LOWER 80S...WITH THE WARMEST READINGS ACROSS THE WESTERN PORTIONS OF THE AREA. LOWS WILL BE MILD...MID 50S TO LOWER 60S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 622 AM CDT WED MAY 22 2013 IFR ACROSS NRN NEB SHOULD IMPROVE TO MVFR THIS MORNING WHILE THE MVFR ALONG I-80 IMPROVES TO VFR. TONIGHT...UPSLOPE EASTERLIES DEVELOP AND MVFR/IFR IS EXPECTED TO REDEVELOP ACROSS WRN NEB PERHAPS AFFECTING THE KLBF TERMAINAL. MEANWHILE...THE RAP MODEL SUGGESTS CLEARING ACROSS NERN NEB AND THE KVTN TERMINAL. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
510 AM CDT WED MAY 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 509 AM CDT WED MAY 22 2013 WHILE THERE IS CERTAINLY NO HIGH-IMPACT WEATHER DURING THE NEXT 24 HOURS...THERE ARE AT LEAST A FEW TRICKY ELEMENTS AT HAND...INCLUDING THE EXTENT OF LOW STRATUS AND ITS POSSIBLE INFLUENCE ON A FAIRLY DECENT SOUTHWEST-NORTHEAST TEMP GRADIENT...AND ALSO THE EXTENT OF SPRINKLES/LIGHT RAIN SHOWERS MAINLY THIS MORNING IN THE NORTHEAST. 08Z OBJECTIVE SURFACE ANALYSIS REVEALS NO MAJOR FEATURES ACROSS THE CENTRAL PLAINS...WITH THE CWA POSITIONED BETWEEN A MODEST 1004 MILLIBAR LOW OVER EASTERN IA...AND A 1014MB HIGH OVER THE NEB PANHANDLE...A SOUTHWARD EXTENSION OF A STRONGER...BROADER HIGH WELL TO THE NORTH IN CANADA. WITHIN THE MODEST PRESSURE GRADIENT BETWEEN THESE FEATURES...A FAIRLY STEADY NORTH-NORTHWEST BREEZE OF 10-15 MPH HAS PREVAILED THROUGH THE NIGH IN MOST AREAS...WITH OCCASIONAL GUSTS OVER 20 MPH. TEMPERATURES WILL START OUT THE MORNING SEASONABLY COOL...WITH EVENTUAL LOWS AIMED INTO THE MID- UPPER 40S ALL AREAS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA FEATURES A CLOSED 500MB LOW DRIFTING SLOWLY EAST...CENTERED NEAR THE IA/SD/NEB BORDER...AND A FAIRLY SHARP MID LEVEL TROUGH AXIS THEN TRAILING SOUTH-SOUTHEAST INTO THE MID-SOUTH STATES. OFF TO THE WEST OF THE LOCAL AREA...A LOW AMPLITUDE MID LEVEL RIDGE IS ALIGNED NORTH-SOUTH THROUGH THE ROCKIES...WITH A FAIRLY VIGOROUS...EXPANSIVE CLOSED LOW SPINNING OVER THE PACIFIC NORTHWEST. WHILE IT HAS TAKEN ITS TIME FORMING...11-3.9 MICRON SATELLITE IMAGERY AND AUTOMATED OBS HAVE FINALLY REVEALED THE FORMATION OF FAIRLY WIDESPREAD LOW STRATUS MAINLY IN THE 1500-2500 FT RANGE OVER MUCH OF THE CWA...ALTHOUGH SOME BREAKS IN THE CLOUDS DO STILL EXIST. ALSO JUST WITHIN THE PAST 90 MINUTES OR SO...AN INCREASING FLARE-UP OF LIGHT RAIN/SPRINKLES HAS TAKEN PLACE MAINLY OVER THE FAR NORTHERN/NORTHEAST CWA...WITH UPSTREAM OBS AT PLACES SUCH AS ONEILL AND ALBION CONFIRMING AT LEAST TRACE AMOUNTS ARE FALLING. TODAY...THE MAIN STORY ALOFT INVOLVES THE CONTINUED SLOW DEPARTURE OF THE CLOSED MID LEVEL LOW...WITH THE CENTER OF THIS FEATURE PROGGED TO ONLY REACH NORTHEAST IA BY 00Z. AT THE SURFACE...A MODEST PRESSURE GRADIENT WILL REMAIN IN PLACE AS HIGH PRESSURE TO THE NORTH NOSES SOUTHWARD...AND THIS IN COMBINATION WITH MIXING TO AT LEAST 850MB IN MOST AREAS WILL RESULT IN SOMEWHAT BREEZY CONDITIONS ESPECIALLY WITHIN THE NORTHEAST 2/3 OF THE CWA...WITH SUSTAINED NORTHWEST WINDS 15 TO POSSIBLY 20 MPH...AND SOME HIGHER GUSTS. THE REAL CHALLENGE TODAY LIES INITIALLY WITH THE EXTENT AND INTENSITY OF RAINFALL...AND ALSO JUST HOW STUBBORN THE LOW STRATUS DECK WILL BE...AND WHETHER OR NOT IT RETREATS SLOW NORTHEAST DURING THE AFTERNOON. STARTING OUT EARLY THIS MORNING THROUGH MID- DAY...HAVE INTRODUCED A MENTION OF SPRINKLES TO A PREVIOUSLY PRECIP-FREE FORECAST FOR FAR NORTHEAST AREAS MAINLY NORTH OF A GREELEY-POLK LINE...AS DECENT LOW-MID LEVEL SATURATION UP TO AROUND 600MB RESIDES MAINLY IN THIS ZONE AND POINTS NORTHEAST...ASSOCIATED WITH A BATCH OF MID LEVEL MOISTURE FOCUSED IN THE DEFORMATION ZONE ON THE BACK-SIDE OF THE DEPARTING LOW. THE VERY SHORT TERM QUESTION THAT WILL NEED PONDERED OVER THE NEXT FEW HOURS IS WHETHER TO EXPAND THIS SPRINKLE MENTION SOUTHWESTWARD CLOSER TO I-80 PER SUGGESTION OF THE LATEST HRRR REFLECTITY PROG...AND ALSO WHETHER TO UP THE ANTE TO A MEASURABLE POP. WILL GIVE IT SOME TIME TO SEE IF AREA OBSERVATIONS SUPPORT A FEW HUNDREDTHS OF ACCUMULATIONS BEFORE POSSIBLY MAKING THIS MOVE. AT ANY RATE...ANY LIGHT RAINFALL IN THE NORTHEAST...ESPECIALLY OF THE POTENTIALLY MEASURABLE VARIETY...IS EXPECTED TO BE OUT OF THE PICTURE BY NOON...AS THE MID LEVELS START TO DRY OUT FROM WEST TO EAST. CLOUD-WISE...HAVE LEANED TOWARD A COMBINATION OF THE NAM AND HRRR...WITH THE EXPECTATION OF A RATHER SHARP SOUTHWEST-NORTHEAST GRADIENT RANGING FROM MOSTLY SUNNY-PARTLY CLOUDY SOUTHWEST TO MOSTLY CLOUDY AT BEST IN THE NORTHEAST. SHAKY CONFIDENCE IN THESE CLOUD DETAILS LEAD TO SOMEWHAT SHAKY CONFIDENCE IN HIGH TEMPS. AT LEAST FOR NOW...NUDGED SOUTHWEST AREAS UP A FEW DEGREES AND NORTHEAST AREAS DOWN A FEW DEGREES VERSUS PREVIOUS...WHILE LEAVING THE CENTRAL RATHER UNCHANGED. AS A RESULT...AM AIMING FROM UPPER 50S-LOW 60S FAR NORTH/NORTHEAST TO MID 60S TRI-CITIES TO MID 70S SOUTHWEST. HOWEVER...AM STARTING TO WONDER IF THE HRRR MIGHT BE ONTO SOMETHING...KEEPING MUCH OF THE NORTHEAST 1/2 OF THE CWA WELL DOWN IN THE MID-50S AT BEST UNDER THE LONGEST-LASTING STRATUS. THIS WILL BEAR WATCHING FOR LATER UPDATES...BUT DON/T WANT TO GO QUITE THIS COOL YET. TURNING TO THE TONIGHT PERIOD...00Z-12Z...CONFIDENCE REMAINS RATHER HIGH IN A LEGITIMATELY DRY NIGHT...WITH THE SOLE POSSIBLE EXCEPTION OF SOME PATCHY LIGHT DRIZZLE IN THE EVENING IN THE NORTH UNDER A LOW STRATUS DECK...BUT THIS SCENARIO IS TOO UNCERTAIN TO INSERT AT THIS TIME. IN THE MID-UPPER LEVELS...THE DEPARTING LOW FINALLY SLIPS FAR ENOUGH EAST TO ALLOW THE RIDGE TO THE WEST TO START BUILDING INTO NEB/KS. ALTHOUGH THERE WILL BE A MODEST NORTHWEST-SOUTHEAST ORIENTED WING OF MID LEVEL MOISTURE ADVECTION/ISENTROPIC LIFT THAT SETS UP FROM SOUTHWEST NEB TO SOUTHEAST KS MAINLY AFTER MIDNIGHT AS EVIDENT ON THE 310K SURFACE...SOUNDINGS SUGGEST THAT LIFT/MOISTURE SHOULD BE INSUFFICIENT FOR PRECIP OVER THE CWA...ALTHOUGH A FEW SHOWERS OR EVEN WEAK STORMS COULD FLARE UP WITHIN A FEW COUNTIES JUST TO THE SOUTH/SOUTHWEST BY SUNRISE. AT THE SURFACE...HIGH PRESSURE WILL CONTINUE OOZING DOWN FROM THE NORTH...KEEPING FAIRLY LIGHT BUT STEADY NORTHERLY BREEZES AROUND 10 MPH IN PLACE. DESPITE THE PRESENCE OF POTENTIALLY DECENT LOW LEVEL SATURATION...THESE BREEZES SHOULD KEEP ANYTHING MORE THAN HAZE/LIGHT FOG AT BAY. THE REAL QUESTION MARK AT THIS POINT TONIGHT AGAIN LIES WITH LOW STRATUS TRENDS. WHILE THE PREVIOUS FORECAST HAD NO WORSE THAN PARTLY CLOUDY SKIES...THE LATEST NAM RUNS AND ASSOCIATED MET GUIDANCE FAIRLY AGGRESSIVELY BRING A BATCH OF LOW STRATUS BACK SOUTHWARD ACROSS MOST OF THE CWA AS THE NIGHT WEARS ON...WITH THIS ESPECIALLY EVIDENT AT 900MB. FOR NOW...HAVE STARTED AN UPWARD TREND IN SKY COVER...BUT VERY WELL MAY NOT BE HIGH ENOUGH ESPECIALLY POST-MIDNIGHT. EVEN IF STRATUS DOES END UP BEING MORE WIDESPREAD THAN CURRENTLY SUGGESTED...CONFIDENCE IS DECENT THAT LOW TEMPS WILL END UP SIMILAR TO THOSE OF THIS MORNING...AND USED A BLEND OF MET/MAV GUIDANCE...AIMING FOR ANOTHER COOL ONE WITH MID 40S MOST SPOTS. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 509 AM CDT WED MAY 22 2013 MODELS ARE IN GOOD AGREEMENT TRANSITIONING A RIDGE OF HIGH PRESSURE ACROSS THE PLAINS ON THURSDAY IN WAKE OF THE DEPARTING UPPER LEVEL LOW. WHILE HEIGHTS ALOFT WILL BE RISING...EXPECT ONLY A MODESTLY WARMER AFTERNOON ON THURSDAY AS 850MB TEMPS ARE EXPECTED TO ONLY REBOUND A COUPLE OF DEGREES AND PLENTY OF CLOUD COVER IS EXPECTED IN EASTERLY UPSLOPE FLOW. AS THE WINDS SHIFT MORE SOUTHEASTERLY THURSDAY NIGHT AND FRIDAY...EXPECT ADDITIONAL MOISTURE TO SURGE NORTHWARD...AND FOR INCREASING INSTABILITY ACROSS THE REGION. THIS BUILDING INSTABILITY COMBINED WITH SOME FORCING FROM THE LOW LEVEL JET...WILL LIKELY RESULT IN A CHANCE OF THUNDERSTORMS THURSDAY NIGHT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA...WHICH WILL BE IN CLOSER PROXIMITY TO THE JET. WITH THE NOSE OF THE NOCTURNAL JET MORE FOCUSED ACROSS THE HEART OF LOCAL AREA FRIDAY AND FRIDAY NIGHT...CANNOT RULE OUT ADDITIONAL ELEVATED SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE ENTIRE FORECAST AREA...WITH THE BEST CHANCES FOR PRECIPITATION COMING DURING THE LATE EVENING AND OVERNIGHT HOURS. THEREAFTER THE MID LEVEL CAP IS EXPECTED TO WEAKEN SUBSTANTIALLY BY SATURDAY AFTERNOON... AND WITH SEVERAL THOUSAND JOULES OF CAPE TO WORK WITH THROUGH THE REMAINDER OF THE LONG TERM PERIODS...WILL LIKELY SEE THUNDERSTORMS AROUND EACH DAY AS PERIODIC VORTICITY MAXIMA EJECT OUT OF THE LONGWAVE TROUGH ACROSS THE WEST COAST. ADDITIONALLY...WITH THESE SUBSTANTIAL CAPE VALUES AND MARGINALLY SUPPORTIVE SHEAR PROFILES...WILL HAVE THE POTENTIAL FOR SOME SEVERE THUNDERSTORMS DEVELOP FROM TIME TO TIME SATURDAY ONWARD...WITH LARGE HAIL AND STRONG THUNDERSTORM WIND GUSTS BEING THE PRIMARY THREATS. TEMPERATURES THROUGH THE PERIOD ARE NOT EXPECTED TO FLUCTUATE A WHOLE LOT AS THERE WILL BE LITTLE CHANGE IN THE UNDERLYING AIRMASS SATURDAY ONWARD...WITH LOWER TO MIDDLE 80S EXPECTED EACH AFTERNOON AND LOWER 60S EXPECTED AT NIGHT. && .AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1250 AM CDT WED MAY 22 2013 ALTHOUGH CONFIDENCE IS HIGH IN VFR VISIBILITY THROUGH THE PERIOD...ALONG WITH LITTLE IF ANY RISK OF PRECIPITATION...CEILING TRENDS APPEAR TO BE SOMEWHAT TRICKY AS PLENTY OF LOWER STRATUS HANGS AROUND THE AREA ON THE BACK SIDE OF A DEPARTING MID LEVEL LOW. STARTING OFF EARLY THIS MORNING...HAVE CONTINUED TO DELAY THE ONSET OF PREVAILING MVFR CEILING UNTIL 09Z...ALTHOUGH AT LEAST BRIEF INSTANCES OF MVFR MAY BE OBSERVED BEFORE THEN. LEANING HEAVILY TOWARD LATEST CEILING TRENDS FROM 00Z NAM AND 05Z GFS LAMP GUIDANCE...KEPT A BROKEN MVFR DECK IN PLACE THROUGH MID- AFTERNOON...WHICH IS SEVERAL HOURS LATER THAN PREVIOUS FORECAST INDICATED. CONFIDENCE STARTS TO WANE ESPECIALLY DURING THE FINAL 9 HOURS OR SO...BUT FOR NOW WILL AIM FOR A RETURN TO AT LEAST LOW- END VFR CEILING BY LATE AFTERNOON. WILL CONTINUE THIS LOW-END VFR THROUGH THE EVENING HOURS...BUT ITS WORTH NOTING THAT THE LATEST NAM/MET GUIDANCE ACTUALLY RE-ESTABLISHES A SOLID MVFR DECK AFTER SUNSET...SO THIS TREND WILL BEAR WATCHING. WIND-WISE...A STEADY NORTH-NORTHWEST BREEZE WILL PREVAIL...WITH GUST POTENTIAL OF 18-22KT THROUGH LATE AFTERNOON BEFORE SLACKENING SOMEWHAT DURING THE EVENING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...SAR AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
730 AM EDT WED MAY 22 2013 .SYNOPSIS... MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY. A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AS OF 722 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE MESOSCALE COLD POOL HAS BEEN ESTABLISHED. WILL SEE PATCHY FOG ACROSS THE REGION THRU 13Z GIVEN SATURATED LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW ACROSS NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS MORNING. THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU EARLY AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS ADDITIONAL RAINFALL IS UNLIKELY THRU ABOUT 19Z. CLOUDS BUT NO PCPN THRU MID AFTN...WILL TREND SKY COVER FROM OVC TO BKN BY NOONTIME. THEREAFTER...THERE IS A SWLY BACKING AND STRENGTHENING OF 850MB FLOW ACROSS WRN PA INTO CENTRAL NY PER MODEL GUIDANCE. FEEL THAT REMNANT OUTFLOW BOUNDARY ACROSS CENTRAL NY WILL ENHANCE ISENTROPIC ASCENT LATE IN THE DAY ACROSS THE ADIRONDACKS AND S-CENTRAL VT...ALLOWING FOR DEVELOPMENT OF SHOWER AND TSTM ACTIVITY. THE 00Z NAM SHOWS DEVELOPMENT OF MUCAPE OF 500-1000 J/KG ACROSS ALL BUT NERN PORTION OF THE FORECAST AREA 21-00Z. RAP SOUNDINGS SHOW A BIT MORE INSTABILITY...UP TO 1500 J/KG...THOUGH SFC DEWPOINTS MAY BE A BIT OVERDONE HERE. BASED ON CONSENSUS OF THE MODELS INCLUDING LOCALLY RUN 4KM WRF...LOOKING FOR DEVELOPMENT OF A FEW STRONG LATE DAY/EVENING TSTMS AS WELL. SPC CALIBRATED SVR PROBABILITIES AND DAY 1 OUTLOOK SUPPORT A FEW SEVERE STORMS...AND MENTIONED GUSTY WINDS AND SMALL HAIL IN THE FORECAST AND HWO FOR LATE AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR EXCEEDS 40 KTS AND IS SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z ALB SOUNDING SHOWED PW VALUES OF 1.52"...AND NWD ADVECTION OF THIS MOIST AIR MASS WILL ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE CONVECTION LATE THIS AFTN INTO THIS EVENING. AFTN TEMPS TODAY HIGHLY DEPEND ON SOME SUNNY BREAKS DURING THE LATE MORNING-MID AFTN PERIOD. ANTICIPATE SOME INTERVALS OF SUN TODAY...AND WITH 850MB TEMPS OF +14C COULD WARM QUICKLY DURING THE EARLY AFTN. HIGH TEMPERATURES IN THE VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT COULD REACH 80F IF WE GET A BIT MORE SUNSHINE AND INSOLATIONAL HEATING. && .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/... AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S. THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+" RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES. FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD. COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 450 AM EDT WEDNESDAY...LOTS OF UNCERTAINTY IN FCST AS WE HEAD INTO THE HOLIDAY WEEKEND...AS LATEST TRENDS SHOW A MUCH DEEPER/SLOWER SYSTEM FOR FRIDAY INTO SUNDAY. HAVE TRENDED TWD THE 00Z ECMWF AND 12Z GFS SOLUTIONS FOR THIS FCST...WHICH SUPPORTS THE MENTION OF RAIN ON SATURDAY INTO SATURDAY NIGHT. IF CRNT TRENDS CONT FOR A MUCH DEEPER AND SLOWER SYSTEM...ADDITIONAL SHOWERS WOULD BE POSSIBLE FOR SUNDAY. LATEST 00Z ECMWF SHOWS NORTHERN AND SOUTHERN STREAM INTERACTION BY 12Z SAT...WHICH HELPS TO PRODUCE A CLOSED AND SLOW MOVING 5H/7H CIRCULATION OVER THE MID ATLANTIC STATES. WHILE SFC LOW PRES TRACKS FROM NJ COAST TO THE GULF OF MAINE BY 18Z SUNDAY. GIVEN THE POSITION AND TRACK OF CLOSED SYSTEM AND ASSOCIATED SFC LOW PRES...EXPECT HEAVIEST QPF TO BE JUST SOUTH AND EAST OF OUR CWA ON FRIDAY INTO SATURDAY. HOWEVER...BACKSIDE DEFORMATION BAND OF ENHANCED MID LVL RH AND ASSOCIATED 850 TO 500MB LIFT IS EXPECTED TO DEVELOP. ITS EXTREMELY DIFFICULT TO DETERMINE EXACT PLACEMENT AND MOVEMENT OF THESE BANDS AND THE ASSOCIATED PRECIP...THEREFORE WL JUST MENTION CHC POPS FOR SATURDAY INTO SATURDAY NIGHT. FEEL SYSTEM WL SLIDE JUST FAR ENOUGH EAST BY SUNDAY TO KEEP FCST DRY ATTM. ON SUNDAY...AS SFC LOW PRES TRACKS INTO THE GULF OF MAINE...LOOK FOR GUSTY NORTHWEST WINDS TO DEVELOP. LATEST SOUNDINGS SHOW 85H WINDS BTWN 35 AND 45 KNOTS...WHICH WITH SOME MIXING WL SUPPORT GUSTS BTWN 25 AND 35 MPH..ESPECIALLY SUNDAY AFTN. PROGGED 85H TEMPS SUPPORT HIGHS ONLY IN THE L/M 50S MTNS TO U50S/L60S FOR SAT AND SUNDAY. EXPECT A RAW/CLOUDY AND BREEZY TYPE DAY ON SUNDAY...WITH BLW NORMAL TEMPS. SFC HIGH PRES WL FINALLY BUILD INTO OUR CWA ON MONDAY INTO TUES...WITH A SLOW CLRING TREND...ALONG WITH WARMER TEMPS. IF SKIES CLR AND WINDS BECM LIGHT...PATCHY FROST WL BE POSSIBLE IN THE COLDER MTN VALLEYS LATE THIS WEEKEND OR EARLY NEXT WEEK. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... THROUGH 12Z THURSDAY...IFR CIGS AT MSS/PBG/SLK WL SLOWLY IMPROVE TO MVFR/VFR BY 15Z THIS MORNING. CIGS WL BE THE SLOWEST TO IMPROVE AT MSS DUE TO A LIGHT NE DRAINAGE FLW DOWN THE SLV. EXPECT SOME CLRING BTWN 15Z-18Z TODAY WITH VFR CONDITIONS...BEFORE MORE SHOWERS/STORMS DEVELOP BY 21Z. A SFC BOUNDARY CONTS TO BE DRAPED ACRS OUR TAF SITES AND WL BE THE FOCUS FOR PRECIP. THIS FRNT...COMBINED WITH SFC HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS SHOWERS/STORMS LATE THIS AFTN THRU THIS EVENING. MVFR TO BRIEF PERIODS OF IFR CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z THURSDAY...ESPECIALLY MSS/SLK/MPV. OUTLOOK 12Z THURSDAY THROUGH SUNDAY... UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO SATURDAY/SUNDAY WITH MVFR...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION BY EARLY NEXT WK. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE WEEKEND...WITH AREAS OF LLVL TURBULENCE. && .HYDROLOGY... 430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST 24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER THURSDAY AND THURSDAY NIGHT. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS SHORT TERM...BANACOS LONG TERM...TABER AVIATION...TABER HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
723 AM EDT WED MAY 22 2013 .SYNOPSIS... MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY. A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AS OF 722 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE MESOSCALE COLD POOL HAS BEEN ESTABLISHED. WILL SEE PATCHY FOG ACROSS THE REGION THRU 13Z GIVEN SATURATED LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW ACROSS NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS MORNING. THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU EARLY AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS ADDITIONAL RAINFALL IS UNLIKELY THRU ABOUT 19Z. CLOUDS BUT NO PCPN THRU MID AFTN...WILL TREND SKY COVER FROM OVC TO BKN BY NOONTIME. THEREAFTER...THERE IS A SWLY BACKING AND STRENGTHENING OF 850MB FLOW ACROSS WRN PA INTO CENTRAL NY PER MODEL GUIDANCE. FEEL THAT REMNANT OUTFLOW BOUNDARY ACROSS CENTRAL NY WILL ENHANCE ISENTROPIC ASCENT LATE IN THE DAY ACROSS THE ADIRONDACKS AND S-CENTRAL VT...ALLOWING FOR DEVELOPMENT OF SHOWER AND TSTM ACTIVITY. THE 00Z NAM SHOWS DEVELOPMENT OF MUCAPE OF 500-1000 J/KG ACROSS ALL BUT NERN PORTION OF THE FORECAST AREA 21-00Z. RAP SOUNDINGS SHOW A BIT MORE INSTABILITY...UP TO 1500 J/KG...THOUGH SFC DEWPOINTS MAY BE A BIT OVERDONE HERE. BASED ON CONSENSUS OF THE MODELS INCLUDING LOCALLY RUN 4KM WRF...LOOKING FOR DEVELOPMENT OF A FEW STRONG LATE DAY/EVENING TSTMS AS WELL. SPC CALIBRATED SVR PROBABILITIES AND DAY 1 OUTLOOK SUPPORT A FEW SEVERE STORMS...AND MENTIONED GUSTY WINDS AND SMALL HAIL IN THE FORECAST AND HWO FOR LATE AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR EXCEEDS 40 KTS AND IS SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z ALB SOUNDING SHOWED PW VALUES OF 1.52"...AND NWD ADVECTION OF THIS MOIST AIR MASS WILL ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE CONVECTION LATE THIS AFTN INTO THIS EVENING. AFTN TEMPS TODAY HIGHLY DEPEND ON SOME SUNNY BREAKS DURING THE LATE MORNING-MID AFTN PERIOD. ANTICIPATE SOME INTERVALS OF SUN TODAY...AND WITH 850MB TEMPS OF +14C COULD WARM QUICKLY DURING THE EARLY AFTN. HIGH TEMPERATURES IN THE VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT COULD REACH 80F IF WE GET A BIT MORE SUNSHINE AND INSOLATIONAL HEATING. && .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/... AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S. THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+" RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES. FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD. COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 450 AM EDT WEDNESDAY...LOTS OF UNCERTAINTY IN FCST AS WE HEAD INTO THE HOLIDAY WEEKEND...AS LATEST TRENDS SHOW A MUCH DEEPER/SLOWER SYSTEM FOR FRIDAY INTO SUNDAY. HAVE TRENDED TWD THE 00Z ECMWF AND 12Z GFS SOLUTIONS FOR THIS FCST...WHICH SUPPORTS THE MENTION OF RAIN ON SATURDAY INTO SATURDAY NIGHT. IF CRNT TRENDS CONT FOR A MUCH DEEPER AND SLOWER SYSTEM...ADDITIONAL SHOWERS WOULD BE POSSIBLE FOR SUNDAY. LATEST 00Z ECMWF SHOWS NORTHERN AND SOUTHERN STREAM INTERACTION BY 12Z SAT...WHICH HELPS TO PRODUCE A CLOSED AND SLOW MOVING 5H/7H CIRCULATION OVER THE MID ATLANTIC STATES. WHILE SFC LOW PRES TRACKS FROM NJ COAST TO THE GULF OF MAINE BY 18Z SUNDAY. GIVEN THE POSITION AND TRACK OF CLOSED SYSTEM AND ASSOCIATED SFC LOW PRES...EXPECT HEAVIEST QPF TO BE JUST SOUTH AND EAST OF OUR CWA ON FRIDAY INTO SATURDAY. HOWEVER...BACKSIDE DEFORMATION BAND OF ENHANCED MID LVL RH AND ASSOCIATED 850 TO 500MB LIFT IS EXPECTED TO DEVELOP. ITS EXTREMELY DIFFICULT TO DETERMINE EXACT PLACEMENT AND MOVEMENT OF THESE BANDS AND THE ASSOCIATED PRECIP...THEREFORE WL JUST MENTION CHC POPS FOR SATURDAY INTO SATURDAY NIGHT. FEEL SYSTEM WL SLIDE JUST FAR ENOUGH EAST BY SUNDAY TO KEEP FCST DRY ATTM. ON SUNDAY...AS SFC LOW PRES TRACKS INTO THE GULF OF MAINE...LOOK FOR GUSTY NORTHWEST WINDS TO DEVELOP. LATEST SOUNDINGS SHOW 85H WINDS BTWN 35 AND 45 KNOTS...WHICH WITH SOME MIXING WL SUPPORT GUSTS BTWN 25 AND 35 MPH..ESPECIALLY SUNDAY AFTN. PROGGED 85H TEMPS SUPPORT HIGHS ONLY IN THE L/M 50S MTNS TO U50S/L60S FOR SAT AND SUNDAY. EXPECT A RAW/CLOUDY AND BREEZY TYPE DAY ON SUNDAY...WITH BLW NORMAL TEMPS. SFC HIGH PRES WL FINALLY BUILD INTO OUR CWA ON MONDAY INTO TUES...WITH A SLOW CLRING TREND...ALONG WITH WARMER TEMPS. IF SKIES CLR AND WINDS BECM LIGHT...PATCHY FROST WL BE POSSIBLE IN THE COLDER MTN VALLEYS LATE THIS WEEKEND OR EARLY NEXT WEEK. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... THROUGH 06Z THURSDAY...ONCE AGAIN ANOTHER CHALLENGING AVIATION FCST WITH REGARDS TO POTENTIAL IFR CIGS/VIS THRU THIS MORNING. CRNT OBS SHOW TAF SITES RANGING FROM VFR AT RUT TO MVFR AT BTV/SLK/MSS AND IFR AT MPV/PBG. RADAR SHOWS BAND OF MODERATE RAIN ACRS THE CPV...WHICH WL BE EAST AND SOUTH OF MPV/RUT TAF SITES BY 07Z. GIVEN 925MB WINDS OF 25 TO 35 KNTS...EXPECT STRATUS DEVELOPMENT WITH IFR LIKELY AT MPV/MSS/SLK BY 08Z THIS MORNING. MEANWHILE...SOUNDINGS SHOW PLENTY OF BL RH AT RUT/BTV/PBG...BUT FEEL MVFR CONDITIONS WITH PERIODS OF IFR CIGS CAN BE EXPECTED TWD MORNING. ANY IFR CIGS SHOULD SLOWLY DISSIPATE BY 15Z AT MPV/MSS/SLK...AS SOUTHERLY WINDS DEVELOP. SFC BOUNDARY CONTS TO BE DRAPED ACRS OUR TAF SITES THIS AFTN. THIS FRNT...COMBINED WITH SFC HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS SHOWERS/STORMS AFT 21Z TODAY...WITH MVFR TO BRIEF PERIODS OF IFR CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z THURSDAY...ESPECIALLY MSS/SLK/MPV. OUTLOOK 06Z THURSDAY THROUGH SUNDAY... UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO EARLY SATURDAY MORNING...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION BY SUNDAY. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE WEEKEND...WITH AREAS OF LLVL TURBULENCE. && .HYDROLOGY... 430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST 24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER THURSDAY AND THURSDAY NIGHT. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS SHORT TERM...BANACOS LONG TERM...TABER AVIATION...TABER HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
451 AM EDT WED MAY 22 2013 .SYNOPSIS... MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY. A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AS OF 418 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE MESOSCALE COLD POOL HAS BEEN ESTABLISHED. REMAINING RAIN SHOWERS ACROSS THE NORTH COUNTRY DEPART EWD INTO NH BY 10Z THIS MORNING. WILL SEE PATCHY FOG AROUND THRU 12Z GIVEN SATURATED LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW ACROSS NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS MORNING. THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU EARLY AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS ADDITIONAL RAINFALL IS UNLIKELY THRU ABOUT 19Z. THEREAFTER...THERE IS A SWLY BACKING AND STRENGTHENING OF 850MB FLOW ACROSS WRN PA INTO CENTRAL NY PER MODEL GUIDANCE. FEEL THAT REMNANT OUTFLOW BOUNDARY ACROSS CENTRAL NY WILL ENHANCE ISENTROPIC ASCENT LATE IN THE DAY ACROSS THE ADIRONDACKS AND S-CENTRAL VT...ALLOWING FOR DEVELOPMENT OF SHOWER AND TSTM ACTIVITY. THE 00Z NAM SHOWS DEVELOPMENT OF MUCAPE OF 500-1000 J/KG ACROSS ALL BUT NERN PORTION OF THE FORECAST AREA 21-00Z. RAP SOUNDINGS SHOW A BIT MORE INSTABILITY...UP TO 1500 J/KG...THOUGH SFC DEWPOINTS MAY BE A BIT OVERDONE HERE. BASED ON CONSENSUS OF THE MODELS INCLUDING LOCALLY RUN 4KM WRF...LOOKING FOR DEVELOPMENT OF A FEW STRONG LATE DAY/EVENING TSTMS AS WELL. SPC CALIBRATED SVR PROBABILITIES AND DAY 1 OUTLOOK SUPPORT A FEW SEVERE STORMS...AND MENTIONED GUSTY WINDS AND SMALL HAIL IN THE FORECAST AND HWO FOR LATE AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR EXCEEDS 40 KTS AND IS SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z ALB SOUNDING SHOWED PW VALUES OF 1.52"...AND NWD ADVECTION OF THIS MOIST AIR MASS WILL ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE CONVECTION LATE THIS AFTN INTO THIS EVENING. AFTN TEMPS TODAY HIGHLY DEPEND ON SOME SUNNY BREAKS DURING THE LATE MORNING-MID AFTN PERIOD. ANTICIPATE SOME INTERVALS OF SUN TODAY...AND WITH 850MB TEMPS OF +14C COULD WARM QUICKLY DURING THE EARLY AFTN. HIGH TEMPERATURES IN THE VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT COULD REACH 80F IF WE GET A BIT MORE SUNSHINE AND INSOLATIONAL HEATING. && .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/... AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S. THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+" RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES. FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD. COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 450 AM EDT WEDNESDAY...LOTS OF UNCERTAINTY IN FCST AS WE HEAD INTO THE HOLIDAY WEEKEND...AS LATEST TRENDS SHOW A MUCH DEEPER/SLOWER SYSTEM FOR FRIDAY INTO SUNDAY. HAVE TRENDED TWD THE 00Z ECMWF AND 12Z GFS SOLUTIONS FOR THIS FCST...WHICH SUPPORTS THE MENTION OF RAIN ON SATURDAY INTO SATURDAY NIGHT. IF CRNT TRENDS CONT FOR A MUCH DEEPER AND SLOWER SYSTEM...ADDITIONAL SHOWERS WOULD BE POSSIBLE FOR SUNDAY. LATEST 00Z ECMWF SHOWS NORTHERN AND SOUTHERN STREAM INTERACTION BY 12Z SAT...WHICH HELPS TO PRODUCE A CLOSED AND SLOW MOVING 5H/7H CIRCULATION OVER THE MID ATLANTIC STATES. WHILE SFC LOW PRES TRACKS FROM NJ COAST TO THE GULF OF MAINE BY 18Z SUNDAY. GIVEN THE POSITION AND TRACK OF CLOSED SYSTEM AND ASSOCIATED SFC LOW PRES...EXPECT HEAVIEST QPF TO BE JUST SOUTH AND EAST OF OUR CWA ON FRIDAY INTO SATURDAY. HOWEVER...BACKSIDE DEFORMATION BAND OF ENHANCED MID LVL RH AND ASSOCIATED 850 TO 500MB LIFT IS EXPECTED TO DEVELOP. ITS EXTREMELY DIFFICULT TO DETERMINE EXACT PLACEMENT AND MOVEMENT OF THESE BANDS AND THE ASSOCIATED PRECIP...THEREFORE WL JUST MENTION CHC POPS FOR SATURDAY INTO SATURDAY NIGHT. FEEL SYSTEM WL SLIDE JUST FAR ENOUGH EAST BY SUNDAY TO KEEP FCST DRY ATTM. ON SUNDAY...AS SFC LOW PRES TRACKS INTO THE GULF OF MAINE...LOOK FOR GUSTY NORTHWEST WINDS TO DEVELOP. LATEST SOUNDINGS SHOW 85H WINDS BTWN 35 AND 45 KNOTS...WHICH WITH SOME MIXING WL SUPPORT GUSTS BTWN 25 AND 35 MPH..ESPECIALLY SUNDAY AFTN. PROGGED 85H TEMPS SUPPORT HIGHS ONLY IN THE L/M 50S MTNS TO U50S/L60S FOR SAT AND SUNDAY. EXPECT A RAW/CLOUDY AND BREEZY TYPE DAY ON SUNDAY...WITH BLW NORMAL TEMPS. SFC HIGH PRES WL FINALLY BUILD INTO OUR CWA ON MONDAY INTO TUES...WITH A SLOW CLRING TREND...ALONG WITH WARMER TEMPS. IF SKIES CLR AND WINDS BECM LIGHT...PATCHY FROST WL BE POSSIBLE IN THE COLDER MTN VALLEYS LATE THIS WEEKEND OR EARLY NEXT WEEK. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... THROUGH 06Z THURSDAY...ONCE AGAIN ANOTHER CHALLENGING AVIATION FCST WITH REGARDS TO POTENTIAL IFR CIGS/VIS THRU THIS MORNING. CRNT OBS SHOW TAF SITES RANGING FROM VFR AT RUT TO MVFR AT BTV/SLK/MSS AND IFR AT MPV/PBG. RADAR SHOWS BAND OF MODERATE RAIN ACRS THE CPV...WHICH WL BE EAST AND SOUTH OF MPV/RUT TAF SITES BY 07Z. GIVEN 925MB WINDS OF 25 TO 35 KNTS...EXPECT STRATUS DEVELOPMENT WITH IFR LIKELY AT MPV/MSS/SLK BY 08Z THIS MORNING. MEANWHILE...SOUNDINGS SHOW PLENTY OF BL RH AT RUT/BTV/PBG...BUT FEEL MVFR CONDITIONS WITH PERIODS OF IFR CIGS CAN BE EXPECTED TWD MORNING. ANY IFR CIGS SHOULD SLOWLY DISSIPATE BY 15Z AT MPV/MSS/SLK...AS SOUTHERLY WINDS DEVELOP. SFC BOUNDARY CONTS TO BE DRAPED ACRS OUR TAF SITES THIS AFTN. THIS FRNT...COMBINED WITH SFC HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS SHOWERS/STORMS AFT 21Z TODAY...WITH MVFR TO BRIEF PERIODS OF IFR CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z THURSDAY...ESPECIALLY MSS/SLK/MPV. OUTLOOK 06Z THURSDAY THROUGH SUNDAY... UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO EARLY SATURDAY MORNING...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION BY SUNDAY. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE WEEKEND...WITH AREAS OF LLVL TURBULENCE. && .HYDROLOGY... 430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST 24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER THURSDAY AND THURSDAY NIGHT. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS SHORT TERM...BANACOS LONG TERM...TABER AVIATION...TABER HYDROLOGY...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
425 AM EDT WED MAY 22 2013 .SYNOPSIS... MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY. A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... AS OF 418 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE MESOSCALE COLD POOL HAS BEEN ESTABLISHED. REMAINING RAIN SHOWERS ACROSS THE NORTH COUNTRY DEPART EWD INTO NH BY 10Z THIS MORNING. WILL SEE PATCHY FOG AROUND THRU 12Z GIVEN SATURATED LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW ACROSS NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS MORNING. THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU EARLY AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS ADDITIONAL RAINFALL IS UNLIKELY THRU ABOUT 19Z. THEREAFTER...THERE IS A SWLY BACKING AND STRENGTHENING OF 850MB FLOW ACROSS WRN PA INTO CENTRAL NY PER MODEL GUIDANCE. FEEL THAT REMNANT OUTFLOW BOUNDARY ACROSS CENTRAL NY WILL ENHANCE ISENTROPIC ASCENT LATE IN THE DAY ACROSS THE ADIRONDACKS AND S-CENTRAL VT...ALLOWING FOR DEVELOPMENT OF SHOWER AND TSTM ACTIVITY. THE 00Z NAM SHOWS DEVELOPMENT OF MUCAPE OF 500-1000 J/KG ACROSS ALL BUT NERN PORTION OF THE FORECAST AREA 21-00Z. RAP SOUNDINGS SHOW A BIT MORE INSTABILITY...UP TO 1500 J/KG...THOUGH SFC DEWPOINTS MAY BE A BIT OVERDONE HERE. BASED ON CONSENSUS OF THE MODELS INCLUDING LOCALLY RUN 4KM WRF...LOOKING FOR DEVELOPMENT OF A FEW STRONG LATE DAY/EVENING TSTMS AS WELL. SPC CALIBRATED SVR PROBABILITIES AND DAY 1 OUTLOOK SUPPORT A FEW SEVERE STORMS...AND MENTIONED GUSTY WINDS AND SMALL HAIL IN THE FORECAST AND HWO FOR LATE AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR EXCEEDS 40 KTS AND IS SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z ALB SOUNDING SHOWED PW VALUES OF 1.52"...AND NWD ADVECTION OF THIS MOIST AIR MASS WILL ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE CONVECTION LATE THIS AFTN INTO THIS EVENING. AFTN TEMPS TODAY HIGHLY DEPEND ON SOME SUNNY BREAKS DURING THE LATE MORNING-MID AFTN PERIOD. ANTICIPATE SOME INTERVALS OF SUN TODAY...AND WITH 850MB TEMPS OF +14C COULD WARM QUICKLY DURING THE EARLY AFTN. HIGH TEMPERATURES IN THE VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT COULD REACH 80F IF WE GET A BIT MORE SUNSHINE AND INSOLATIONAL HEATING. && .SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/... AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S. THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+" RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES. FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD. COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 225 PM EDT TUESDAY...DEPARTING LOW PRESSURE SYSTEM WILL HAVE POSITIVELY TILTED UPPER LEVEL TROUGH MOVE OVER THE NORTH COUNTRY ON FRIDAY...KEEPING CHC OF SHOWERS OVER MUCH OF THE AREA. LATE FRIDAY IN TO FRIDAY NIGHT...TROUGH LOOKS TO TILT NEUTRAL TO NEGATIVE AS THE SFC LOW PUSHES OFF THE NEW ENGLAND COAST. SFC LOW TRAVERSES NEWD NEAR NEWFOUNDLAND...KEEPING BACK/WRN EDGE OF PRECIP NEAR VT...THEREFORE HAVE KEPT SLGT CHC POPS OVER VT FRIDAY NIGHT THROUGH FIRST HALF OF SATURDAY. AS HIGH PRESSURE BUILDS OVER SW HUDSONS BAY...EXTENDING SWD OVER THE CENTRAL GREAT LAKES...A SHORTWAVE ROTATING ABOUT THE UPPER LEVEL LOW OVER NEW ENGLAND WILL BE FAIRLY DRY BUT BRING CLOUDS FOR THE REST OF SATURDAY INTO SATURDAY NIGHT. ON SUNDAY...SOME TROUGHINESS REMAINING OVER ERN ZONES...WITH CLOUDS OVER MOST OF VT. THE SFC HIGH PRESSURE AND SOME UPPER LEVEL RIDGING WILL TAKE HOLD OF THE REGION FOR THE REST OF THE PERIOD. BELOW NORMAL MAX TEMPS WILL GRADUALLY TREND WARMER THROUGHOUT THE PERIOD WITH MIN TEMPS GENERALLY IN THE 40S. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... THROUGH 06Z THURSDAY...ONCE AGAIN ANOTHER CHALLENGING AVIATION FCST WITH REGARDS TO POTENTIAL IFR CIGS/VIS THRU THIS MORNING. CRNT OBS SHOW TAF SITES RANGING FROM VFR AT RUT TO MVFR AT BTV/SLK/MSS AND IFR AT MPV/PBG. RADAR SHOWS BAND OF MODERATE RAIN ACRS THE CPV...WHICH WL BE EAST AND SOUTH OF MPV/RUT TAF SITES BY 07Z. GIVEN 925MB WINDS OF 25 TO 35 KNTS...EXPECT STRATUS DEVELOPMENT WITH IFR LIKELY AT MPV/MSS/SLK BY 08Z THIS MORNING. MEANWHILE...SOUNDINGS SHOW PLENTY OF BL RH AT RUT/BTV/PBG...BUT FEEL MVFR CONDITIONS WITH PERIODS OF IFR CIGS CAN BE EXPECTED TWD MORNING. ANY IFR CIGS SHOULD SLOWLY DISSIPATE BY 15Z AT MPV/MSS/SLK...AS SOUTHERLY WINDS DEVELOP. SFC BOUNDARY CONTS TO BE DRAPED ACRS OUR TAF SITES THIS AFTN. THIS FRNT...COMBINED WITH SFC HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS SHOWERS/STORMS AFT 21Z TODAY...WITH MVFR TO BRIEF PERIODS OF IFR CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z THURSDAY...ESPECIALLY MSS/SLK/MPV. OUTLOOK 06Z THURSDAY THROUGH SUNDAY... UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO EARLY SATURDAY MORNING...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION BY SUNDAY. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE WEEKEND...WITH AREAS OF LLVL TURBULENCE. && .HYDROLOGY... 430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST 24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER THURSDAY AND THURSDAY NIGHT. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS SHORT TERM...BANACOS LONG TERM...KGM AVIATION...TABER HYDROLOGY...BANACOS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
805 PM EDT THU MAY 23 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA OVERNIGHT AND EARLY FRIDAY MORNING. A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION WITH CLEAR AND COOL CONDITIONS FOR MOST OF THE HOLIDAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 240 PM THURSDAY... UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD THIS AFTERNOON AIDED BY A 50-75 KNOT UPPER JET OVER THE UPPER MISSISSIPPI VALLEY. THE SURFACE COLD FRONT IS CURRENTLY MOVING ACROSS CENTRAL TENNESSEE AND WILL TAKE ITS TIME MOVING ACROSS THE MOUNTAINS THIS EVENING. THE MAIN 500 MB VORT MAX ASSOCIATED WITH THE FRONT WILL NOT ARRIVE UNTIL CLOSER TO 00Z. FRONTAL PASSAGE WILL FINALLY OCCUR AFTER 00Z IN THE NORTHWEST PIEDMONT...CLOSER TO 3Z IN THE TRIANGLE AREA...AND NEAR 6Z FOR THE I-95 CORRIDOR. CURRENT RADAR TRENDS SHOW A MYRIAD OF SURFACE BOUNDARIES LEFT OVER FROM LAST NIGHTS CONVECTION AND DIFFERENTIAL HEATING THIS MORNING. IN ADDITION A SMALL SHORTWAVE TROUGH IS MOVING NORTHWARD FROM UPSTATE SOUTH CAROLINA. AT THIS TIME THE BOUNDARY INITIATING THE MOST CONVECTION SPANS SW TO NE FROM THE ROCKINGHAM AREA TO ROANOKE RAPIDS. AT THIS TIME INGREDIENTS FOR THUNDERSTORMS ARE A BIT HEALTHIER THAN IN PREVIOUS DAYS. CURRENTLY THERE IS ABOUT 1000 ML CAPE IN THE EAST WITH LOW LEVEL LAPSE RATES BETWEEN 7-8. EFFECTIVE SHEAR IS AROUND 20 KNOTS. RAP SOUNDINGS SHOW VERY TALL SKINNY CAPE IN THE HAIL GROWTH ZONE MAKING SEVERE HAIL UNLIKELY IN THIS SCENARIO BUT PEA HAIL IS CERTAINLY POSSIBLE. STRAIGHT HODOGRAPHS WITH 20 KNOTS OF SHEAR SUPPORT A MORE LINEAR MULTICELLULAR CONVECTIVE MODE. THERE IS A RELATIVELY DRIER LAYER NEAR 800 MB WITH A VERY MODEST INVERTED V MAKING SEVERE WINDS A LITTLE BIT MORE POSSIBLE THAN IN PREVIOUS DAYS BUT GUSTS WILL MORE LIKELY TOP OUT IN THE 30-40 KNOT RANGE. CURRENT SPC ANALYSIS ALSO SHOWS AN AREA OF 500-700 J/KG OF DCAPE ACROSS THE SOUTH CENTRAL PORTION OF THE CWA. DESPITE PARAMETERS BEING RELATIVELY BETTER TODAY...MID LEVEL LAPSE RATES ARE STILL VERY WEAK. OVERALL BULK SHEAR IS LOW. THERE IS ENOUGH LIFT IN THE MID LEVELS TO SUPPORT MORE LIGHTNING THAN IN PREVIOUS DAYS BUT ANY SEVERE THREAT WILL BE FAIRLY SUBDUED. AS THE VORT MAX APPROACHES FROM THE NORTHWEST...DYNAMICS WILL IMPROVE SLIGHTLY AND IF THERE IS STILL CONVECTION AROUND THE NORTHWEST PIEDMONT WOULD BE THE MOST LIKELY LOCATION TO SEE SEVERE WEATHER. WITH SEVERE POTENTIAL LOW...HEAVY RAIN AND FLOODING WILL AGAIN BE THE LARGEST THREAT. WHILE ONLY A QUARTER TO A HALF OF AN INCH OF WIDESPREAD PRECIPITATION IS EXPECTED...AREAS RECEIVING HEAVY RAINS OVER THE PAST FEW DAYS WOULD BE A BIT MORE PRIMED FOR URBAN AND SMALL STREAM FLOODING. CORFIDI VECTORS SHOW THAT STORMS SHOULD BE PROGRESSIVE ENOUGH TO AVOID TRAINING BUT ORIENTATION OF INDIVIDUAL BOUNDARIES COULD ALLOW FOR SOME TRAINING CELLS THIS AFTERNOON. MOISTURE TRANSPORT...PW VALUES AND SURFACE CONVERGENCE ARE ALL BEST IN THE COASTAL PLAIN THIS AFTERNOON...MAKING THIS THE MOST LIKELY LOCATION FOR FLOODING TODAY. SOUTH SOUTHWESTERLY WINDS TODAY WILL SHIFT TO NORTHWESTERLY AFTER FRONTAL PASSAGE AND SUSTAINED WINDS WILL ELEVATE TO 10-15 KNOTS. HIGHS TODAY WILL BE LARGELY DEPENDENT UPON CONVECTION AND CLOUD COVER BUT IN GENERAL...UPPER 70S TO NEAR 80 IN THE NW AND LOWER TO MID 80S IN THE SOUTH. LOWS WILL BE DEPENDENT UPON THE TIMING OF THE FRONTAL PASSAGE UPPER 50S TO NEAR 60 IN THE NW AND MID 60S SE. SOME MVFR CEILINGS OR VISIBILITIES COULD BE POSSIBLE IN THE EAST BEFORE MAIN FRONT MOVES THROUGH EARLY FRIDAY MORNING. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... AS OF 240 PM THURSDAY... FRIDAY AND FRIDAY NIGHT... THE COLD FRONT WILL SLOWLY MOVE OUT OF THE EASTERN AREAS OF THE CWA DURING THE EARLY MORNING. AFTER FRONTAL PASSAGE WINDS WILL SHIFT TO NORTHWESTERLY AND INCREASE IN SPEED TO 15 KNOTS SUSTAINED. A VERY TALL MIXED LAYER DURING THE AFTERNOON AND THE PASSAGE OF A 30 KNOT 850 JET WILL HELP TRANSPORT SOME OF THOSE WINDS DOWN TO THE SURFACE AND GUSTS OF 25-30 KNOTS ARE POSSIBLE FRIDAY AFTERNOON. SKIES WILL GRADUALLY CLEAR OUT AND THICKNESSES SUPPORT HIGH TEMPERATURES IN THE MID 70S IN MOST LOCATIONS. ON FRIDAY NIGHT WINDS WILL REMAIN BLUSTERY WHICH WILL HELP TO OFFSET RADIATIONAL COOLING A BIT AS THICKNESSES SUPPORT LOWS NEAR 40 DEGREES BUT WILL GO A BIT CONSERVATIVE IN THE LOWER 40S. STILL VERY POSSIBLE TO BREAK THE LOW TEMPERATURE RECORDS AT BOTH RDU AND GSO WHICH ARE BOTH 43 DEGREES. -ELLIS SATURDAY THROUGH SUNDAY NIGHT... A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY SUN...FAVOR TEMPS IN THE LOW-MID 70S. TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS. FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY END UP BEING 2-3 DEGREES COOLER THAN FORECAST. MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE 1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S ELSEWHERE. -WSS && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY... 12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE ECMWF HELD ONTO THE L/W TROUGH ALONG THE EASTERN SEABOARD RESULTING IN A SLOWER WARMING TREND WHERE AS THE GFS WITH ITS BUILDING MID-UPPER HEIGHTS ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE ECMWF SOLUTION OF A LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW ENGLAND COAST AND AN AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL MAINTAIN A NW FLOW ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT POSSIBLE DISTURBANCES ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN THE UPPER MID WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION. IF THIS WERE TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER ANYTIME BETWEEN WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE RIDGE BUILDING CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO OUR NORTH. FOR NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT TUESDAY INTO THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON TEMPS NEAR 80-LOWER 80S TUESDAY...AND LOW-MID 80S WEDNESDAY/THURSDAY. AGAIN...IF GFS VERIFIES...WED/THU COULD SEE TEMPS IN THE UPPER 80S TO NEAR 90. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AS OF 805 PM THURSDAY... NUMEROUS SHOWERS AND STORMS DEVELOPED BETWEEN KRDU AND KRWI/KFAY AROUND 18Z...AND HAVE SINCE PUSHED EAST INTO THE COASTAL PLAIN...LEAVING VFR CONDITIONS ACROSS CENTRAL NC WITH A SOUTH-SOUTHWESTERLY SURFACE WIND. A SECOND LINE OF STORMS HAS RECENTLY DEVELOPED AND EXTENDS FROM KRNK TO KTNB AS A COLD FRONT AND UPPER LEVEL TROUGH APPROACHES FROM THE WEST. IT APPEARS THIS LINE OF STORMS SHOULD SWEEP ACROSS THE TRIAD AREA BETWEEN 00Z AND 02Z...MOVING TO KRDU BY 03-04Z...AND IF IT HOLDS TOGETHER...REACHING KFAY/KRWI BY 05-06Z. A STRONG WIND SHIFT TO WEST-NORTHWESTERLY WINDS WILL ACCOMPANY THE LINE..AND CONFIDENCE IS FAIRLY HIGH THAT GUSTS WILL EXCEED 30KT AT KGSO/KINT. IN ADDITION..CEILINGS AND VSBYS MAY BRIEFLY FALL TO TO MVFR. FURTHER EAST...MVFR CEILINGS MAY DEVELOP AHEAD OF THE LINE DUE TO ABUNDANT LOW LEVEL MOISTURE...BUT A SWITCH NORTHWESTERLY WINDS SHOULD HELP TO SCOUR CEILINGS BY FRIDAY MORNING. VFR CONDITIONS WILL CONTINUE ON FRIDAY WITH WINDS STRENGTHENING TO NEAR 15KT AND GUSTING TO AT LEAST 25KT AS AN UPPER LEVEL TROUGH SWINGS ACROSS THE AREA. OUTLOOK... VFR CONDITIONS ARE EXPECTED THROUGH THE WEEKEND. && .CLIMATE... MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE NEAR RECORD MIN TEMPS FOR THE DATE. RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH RDU 43 / 1967 43 / 1979 GSO 43 / 1956 42 / 1930 .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLAES NEAR TERM...ELLIS SHORT TERM...ELLIS/WSS LONG TERM...WSS AVIATION...SMITH CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1015 AM EDT WED MAY 22 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE EASTERN CAROLINAS THROUGH THURSDAY. SHOWERS AND THUNDERSTORMS WILL INCREASE THURSDAY AND THURSDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL CROSS THE REGION FRIDAY MORNING. A MUCH COOLER AND DRIER AIRMASS WILL FOLLOW...COMPLEMENTS OF A CANADIAN HIGH PRESSURE...AND AFFECT THE AREA THIS WEEKEND. THE HIGH WILL SLIDE OFF THE EAST COAST EARLY NEXT WEEK WITH TEMPERATURES REBOUNDING TO NEAR NORMAL...ALONG WITH AN INCREASE IN AFTERNOON SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 10:30 AM WEDNESDAY...FIRST SHOWERS OF THE DAY JUST STARTING TO POP OVER THE COASTAL COUNTIES. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST EARLY THIS MORNING. EARLIER DISCUSSION FROM 3:00 AM FOLLOWS: THE WEAK UPPER LEVEL SHEAR AXIS THAT HAS BEEN NEARLY STATIONARY ACROSS THE EASTERN CAROLINAS FOR THE PAST TWO DAYS HAS DECAYED AS LIGHT SOUTHERLY FLOW HAS ESTABLISHED ITSELF THROUGHOUT THE 500-700 MB LAYER. ALTHOUGH THE OVERALL AIRMASS REMAINS THE SAME AS YESTERDAY...TRIGGERS FOR TODAY`S CONVECTION WILL BE SURFACE BOUNDARIES ONLY. EARLY MORNING CONVECTION MOVING ONSHORE ACROSS OAK ISLAND THROUGH WILMINGTON IS ASSOCIATED WITH A LOW-LEVEL CONVERGENCE AXIS WHERE SOUTHWEST WINDS ACROSS THE SC COASTAL WATERS CONVERGE WITH SOUTH WINDS CLOSER TO THE GULF STREAM. THIS CONVECTIVE ACTIVITY SHOULD BECOME MORE ISOLATED IN NATURE TOWARD DAYBREAK...BUT THE REMNANT CONVERGENCE AXIS MAY BECOME ACTIVE AGAIN BY LATE MORNING AS THE DEVELOPING SEABREEZE CIRCULATION CREATES ADDITIONAL CONVERGENCE IN THE LOW LEVELS. BY EARLY AFTERNOON WE SHOULD HAVE A DEVELOPING FIELD OF SCATTERED SHOWERS ACROSS MOST OF THE AREA EAST OF I-95 AND WEST OF THE BEACHES. AS THE SEABREEZE MAKES GOOD PROGRESS INLAND THIS AFTERNOON EXPECT CLEARING CONDITIONS WITHIN 20 MILES OF THE COAST...BUT SHOWER AND T-STORM CHANCES WILL INCREASE TO 30-40 PERCENT WEST OF THE SEABREEZE BOUNDARY IN A MODERATELY UNSTABLE AND COMPLETELY UNCAPPED AIRMASS. 850 MB TEMPS IN THE +15C TO +17C RANGE WILL SUPPORT TEMPERATURES IN THE MID 80S INLAND TODAY...WITH LOWER 80S CLOSER TO THE COAST. SOUTHWESTERLY WINDS WILL INCREASE ABOVE THE SURFACE TONIGHT AS A MID-LATITUDE STORM SYSTEM SWEEPS EAST INTO THE GREAT LAKES. A WEAK VORTICITY MAXIMUM LOCATED ACROSS GEORGIA THIS EVENING WILL MOVE EASTWARD AND SHOULD SUSTAIN ISOLATED TO SCATTERED SHOWER AND T-STORM POTENTIAL THROUGH THE NIGHT ACROSS THE EASTERN CAROLINAS. WHILE THE SC PEE DEE REGION WILL BE THE CLOSEST GEOGRAPHICALLY TO THE INCOMING VORT ALOFT...PRECIP CHANCES MAY ACTUALLY BECOME GREATEST IN THE WILMINGTON AREA AS MODELS ARE INSISTENT THAT A BLOB OF GULF STREAM CONVECTION WILL MOVE NORTH INTO THE CAPE FEAR REGION OVERNIGHT. LOWS SHOULD FALL TO 66-70...WARMEST AT THE BEACHES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...THIS PERIOD WILL BE HIGHLIGHTED BY THE EVOLUTION OF A RATHER DEEP MID-LEVEL TROF THAT WILL DOMINATE THE WEATHER ACROSS THE FA BY THE END OF THIS PERIOD. AT THE BEGINNING OF THE SHORT TERM...THE AMPLIFYING UPPER TROF IS PROGGED TO BE JUST EAST OF THE MISSISSIPPI RIVER...AND BY LATE FRIDAY NIGHT ITS NORTH TO SOUTH TROF AXIS WILL HAVE MOVED JUST OFF THE NORTH AND SOUTH CAROLINA COASTS...VIA NAM AND GFS MODELS. MODELS AT TIMES HAVE TRIED TO MAKE THIS AN AMPLIFIED FULL LATITUDE TROF BUT INDIVIDUAL VORTS/IMPULSES ROTATING THROUGH THIS UPPER FEATURE...ARE PROGGED TO MOVE AT DIFFERENT SPEEDS AND THUS PREVENTING THE CARVING OF A TRUE FULL LATITUDE TROF. ONE OF THE STRONGER VORTS IS PROGGED TO TRACK ACROSS THE FA FRIDAY AFTERNOON/EVENING AS DYNAMICS FROM THIS FEATURE AND COLDER TEMPS ALOFT PROVIDE ENOUGH INSTABILITY FOR ISOLATED CONVECTION. AT THE SURFACE...WESTERN ATLANTIC RIDGING WILL CONTINUE ACROSS THE FA EARLY THURSDAY. A PRE-FRONTAL OR LEE SIDE TROF ORIENTED N-S WILL DEVELOP ACROSS THE WEST-CENTRAL CAROLINAS AND BECOME THE FOCUS FOR CONVECTION DEVELOPMENT AS IT SLOWLY PROGRESSES EASTWARD. IN ADDITION MID-DAY/AFTERNOON DIURNALLY INDUCED CONVECTION WILL BREAK OUT ACROSS THE COASTAL PORTIONS OF THE ILM CWA. WILL INDICATE 50 POPS INLAND...WITH 30-40 CLOSER TO THE COAST DURING THE DAY THURSDAY. FOR THURSDAY NIGHT...THE APPROACHING COLD FRONT WILL BECOME THE PRIMARY FORCE FOR INDUCING CONVECTION. HOWEVER...THE SUB-TROPICAL/TROPICAL MOISTURE FEED WILL HAVE BEEN PUSHED OFFSHORE AND NO LONGER THE PRIMARY SOURCE. THINKING IS THAT ENOUGH MOISTURE WILL REMAIN FOR ADDITIONAL CONVECTION TO FIRE AHEAD OF THE COLD FRONT...DEPENDING HOW MUCH THE ATM IS ABLE TO DE-STABILIZE FROM THE CONVECTION THAT DEVELOPED EARLIER IN THE DAY. AS A RESULT...WILL HIGHLIGHT 40-50 POPS IN THE EVENING AND SLOWLY DROP THEM TO SLIGHT CHANCE OVERNIGHT. MODELS AFTER MIDNIGHT FRIDAY...DIVERGE FROM ONE ANOTHER WITH RESPECT TO THEIR SOLUTIONS RELATED TO THE TIMING AND PLACEMENT OF THE COLD FRONT. FOR EXAMPLE THE NAM AND CANADIAN HAVE THE FRONT OFF THE CAROLINA COASTS BY DAYBREAK FRI...WHEREAS THE GFS LAGS BEHIND AND ONLY HAS IT PROGRESSING THROUGH THE COASTAL CAROLINAS BY DAYBREAK FRI. WILL LEAN TOWARD THE SLIGHTLY SLOWER PROGRESSION OF THE CFP. POST FRONTAL DRIER AIR FINALLY ADVECTS ACROSS THE FA DURING THE DAY FRI. CANADIAN HIGH PRESSURE WILL FINALLY PROVIDE RELIEF FROM THE HUMID SUBTROPICAL/TROPICAL AIR MASS THAT AFFECTED THE FA FOR MUCH OF THIS WEEK. AS FOR MAX/MIN TEMPS...A RANGE OF 80 TO 85 FOR HIGHS THU...SIMILAR TO WHAT THE NAM/GFS MOS GUIDANCE SHOWS. THE COLD AIR ADVECTION BEHIND THE CFP WILL LAG BEHIND...AND BE OFFSET BY A DOWNSLOPE TRAJECTORY IN THE WIND FIELDS. AS A RESULT...HAVE GONE ABOVE GUIDANCE FOR FRIDAYS HIGHS WITH THE COASTAL COUNTIES LIKELY TO BE WARMER THAN INLAND. A COMPROMISED MOS GUIDANCE MIN FORECAST WAS USED. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...FOR SATURDAY THRU MONDAY MID LEVEL FEATURES REMAIN RELATIVELY UNCHANGED WITH THE TROF AXIS ASSOCIATED WITH THE UPPER TROF HAVING ONLY PROGRESSED JUST OFF THE EAST COAST. THE CENTRAL U.S. WILL BE HIGHLIGHTED BY AN UPPER RIDGE WITH ITS AXIS RUNNING N-S ALONG THE MISSISSIPPI RIVER. BY TUESDAY...THE EUROPEAN FLATTENS THIS RIDGE WHEREAS THE GFS PROGRESSES IT EASTWARD AND MAINTAINING ITS IDENTITY. PREFERRED THE GFS SOLUTION AT THIS POINT. AT THE SFC...CANADIAN HIGH PRESSURE TO RIDGE ACROSS THE FA SATURDAY. ITS CENTER IS PROGGED TO BREAK APART BY SUNDAY...WITH THE SOUTHERN EXTENT OF ITS CENTER MOVING ACROSS AND OFFSHORE FROM THE CAROLINAS MONDAY AND TUESDAY. SUBSIDENCE ALOFT WILL KEEP A LID ON THE DIURNALLY DRIVEN CU FROM DEVELOPING IN THE VERTICAL. THEREFORE NO POPS THROUGH SUNDAY. FOR LATE SUNDAY NIGHT THRU TUESDAY...MODELS ARE HINTING AT A BACK-DOOR COLD FRONT DROPPING SOUTHWARD...AND BECOMING STATIONARY JUST NORTH OF THE FA. THIS MAY BECOME AN AID TO POSSIBLE MCS/MCC THAT DEVELOP WELL UPSTREAM MON AND TUE...WHICH WILL FOLLOW THE NW-SE UPPER FLOW. TOO FAR OUT IN TIME TO PREDICT THEIR TIMING...HOWEVER ENOUGH OF A POSSIBILITY TO PLACE A LOW CHANCE POP IN THE GOING FORECAST. FOR THIS UPCOMING MEMORIAL DAY WEEKEND...SATURDAY THROUGH MONDAY MORNING TEMPS ACROSS THE FA WILL RUN 5 TO 10 DEGREES BELOW NORMAL...ESPECIALLY WITH OVERNIGHT LOWS. FOR MONDAY THRU TUESDAY...WILL BE LOOKING AT NEAR NORMAL TEMPS. IF THE BACK-DOOR COLD FRONT DROPS FURTHER SOUTH THAN ANTICIPATED...THE NW FLOW AHEAD OF IT COULD PUSH TEMPS WELL INTO THE 80S TO AROUND 90...MUCH HIGHER THAN THE CURRENT MOS GUIDANCE. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...A BIT LESS DEEP MOISTURE TODAY WITH MAINLY SOUTHERLY FLOW. A LOW LCL INDICATES A MVFR CEILING COULD FORM AN HOUR OR SO AFTER SUNRISE. HRRR MODEL INDICATES AN EARLY START TO CONVECTION ALONG THE SEA BREEZE TODAY...WITH SHOWERS LIKELY NOT AS STRONG DUE TO LACK OF MOISTURE. MOST OF THE ACTIVITY WILL ACTUALLY BE BETWEEN THE INLAND AND COASTAL TERMINALS...NEARING THE INLAND TERMINALS BY 18Z. SOUTHERLY FLOW WILL BE A BIT GUSTY THIS AFTERNOON...DIMINISHING DIURNALLY THIS EVENING. WILL REEVALUATE BACK END OF TAFS ON THE NEXT MODEL RUN AS ANOTHER SLUG OF MOISTURE ADVECTS IN FROM THE SOUTH. EXTENDED OUTLOOK...SHOWERS/T-STORMS POSSIBLE THURSDAY THROUGH EARLY FRIDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 700 AM WEDNESDAY...LATEST OBS SHOW LIGHT SOUTH WINDS WITH SEAS IN THE 3 TO 4 FT RANGE. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. EARLIER DISCUSSION FROM 3:00 AM FOLLOWS: BERMUDA HIGH PRESSURE WILL MOVE LITTLE THROUGH TONIGHT...CONTINUING TO PUMP AIR FROM THE CARIBBEAN NORTHWARD ACROSS THE CAROLINA COASTAL WATERS. LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES...TOO FAR AWAY FOR ANY DIRECT AFFECTS JUST YET. A TYPICAL SUMMER/TROPICAL WEATHER REGIME IS EXPECTED WITH SCATTERED SHOWERS AND THUNDERSTORMS OVER THE COASTAL WATERS ENDING THIS MORNING...THEN REDEVELOPING TONIGHT. MODELS ARE ACTUALLY QUITE INSISTENT THAT AT LEAST ONE CONCENTRATED BATCH OF CONVECTION COULD ROLL IN OFF THE GULF STREAM OVERNIGHT AND TOWARD COASTAL NORTH CAROLINA. OUTSIDE OF ANY SHOWER AND THUNDERSTORM ACTIVITY...SOUTH WINDS SHOULD AVERAGE 10-15 KNOTS WITH 3-4 FT SEAS. DOMINANT WAVE PERIODS AT THE FRYING PAN SHOALS BUOY ARE 6 SECONDS...WITH YESTERDAY`S 10 SECOND EASTERLY SWELL HARDLY REGISTERING ANYMORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WESTERN ATLANTIC RIDGING WILL PROVIDE A RATHER SOLID 15 KT SOUTHERLY FLOW DURING THU...BECOMING SW LATE THU AFTERNOON AND NIGHT. THE SFC PG WILL TIGHTEN BETWEEN THE APPROACHING COLD FRONT AND THE WESTERN ATLANTIC HIGH CENTERED WELL OFFSHORE FROM THE SE U.S.COAST. COULD SEE 15 TO 20 KT WITH SOME HIGHER GUSTS. CFP SLATED FOR AFTER DAYBREAK FRI...WITH WINDS VEERING TO W TO NW 10 TO 15 KT...INCREASING TO 15 TO 25 KT FRIDAY NIGHT DUE TO COLD AIR ADVECTION COMBINED WITH A TIGHTENED SFC PG. SIGNIFICANT SEAS WILL RANGE FROM 2 TO 4 FT THU...BUILDING TO 3 TO 5 FT LATE THU THROUGH EARLY FRI. TEMPORARILY DROPPING BACK TO 2 TO 4 FT DURING FRIDAY...THEN BUILDING BACK TO 3 TO 5 FT FRI NIGHT WITH 6 FOOTERS POSSIBLE OUTER WATERS OFF CAPE FEAR. SIG. SEAS WILL PRIMARILY BE DRIVEN BY AN ESE GROUND SWELL AT 8 TO 9 SECOND PERIODS DURING EARLY THU...WITH 4 TO 6 SECOND PERIOD WIND DRIVEN WAVES TO DOMINATE LATE THU THRU FRI NITE. SCEC CONDITIONS POSSIBLE FOR ALL WATERS...WITH A BORDERLINE SCA FOR THE ILM NC WATERS DURING THE INFLUX OF COLD AIR FRI NIGHT. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...POSSIBLE SCEC OR SCA CONDITIONS WILL PEAK DURING EARLY SATURDAY...WITH A DIMINISHING AND SUBSIDING TREND FOR WINDS AND SIGNIFICANT SEAS RESPECTIVELY DURING THE LATTER 2/3RDS OF THIS PERIOD. ALL IN RESPONSE TO THE CENTER OF THE MODERATING CANADIAN HIGH PUSHING ACROSS THE LOCAL WATERS SUNDAY THROUGH SUNDAY NIGHT. WINDS ARE PROGGED TO BECOME VARIABLE IN DIRECTION DURING SUNDAY AND SUNDAY NIGHT AT 10 KT OR LESS. SIGNIFICANT SEAS WILL BE DRIVEN BY LOCALLY PRODUCED SHORT PERIOD WIND DRIVEN WAVES ON SATURDAY...WITH AN 8 TO 9 SECOND PERIOD SMALL EASTERLY SWELL DOMINATING ON SUNDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...DCH NEAR TERM...REK/TRA SHORT TERM...DCH LONG TERM...DCH AVIATION...TRA/SGL MARINE...DCH/REK/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
703 AM EDT WED MAY 22 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE EASTERN CAROLINAS THROUGH THURSDAY. SHOWERS AND THUNDERSTORMS WILL INCREASE THURSDAY AND THURSDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL CROSS THE REGION FRIDAY MORNING. A MUCH COOLER AND DRIER AIRMASS WILL FOLLOW...COMPLEMENTS OF A CANADIAN HIGH PRESSURE...AND AFFECT THE AREA THIS WEEKEND. THE HIGH WILL SLIDE OFF THE EAST COAST EARLY NEXT WEEK WITH TEMPERATURES REBOUNDING TO NEAR NORMAL...ALONG WITH AN INCREASE IN AFTERNOON SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 700 AM WEDNESDAY...EARLIER SHOWER ACTIVITY OFFSHORE AND OVER WILMINGTON DISSIPATED A COUPLE HOURS AGO. THE ATMOSPHERE REMAINS SUPPORTIVE OF AT LEAST SHALLOW CONVECTION...BUT CERTAINLY WITH LESS COVERAGE THAN WHAT WAS EXPERIENCED YESTERDAY GIVEN DRIER AIR ALOFT AND SUBSEQUENT LOWER PRECIPITABLE WATER VALUES. THIS WILL REDUCE PRECIPITATION EFFICIENCY AND SHOULD LEAD TO LOWER RAINFALL TOTALS EVEN WHERE IT DOES RAIN. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST EARLY THIS MORNING. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... THE WEAK UPPER LEVEL SHEAR AXIS THAT HAS BEEN NEARLY STATIONARY ACROSS THE EASTERN CAROLINAS FOR THE PAST TWO DAYS HAS DECAYED AS LIGHT SOUTHERLY FLOW HAS ESTABLISHED ITSELF THROUGHOUT THE 500-700 MB LAYER. ALTHOUGH THE OVERALL AIRMASS REMAINS THE SAME AS YESTERDAY...TRIGGERS FOR TODAY`S CONVECTION WILL BE SURFACE BOUNDARIES ONLY. EARLY MORNING CONVECTION MOVING ONSHORE ACROSS OAK ISLAND THROUGH WILMINGTON IS ASSOCIATED WITH A LOW-LEVEL CONVERGENCE AXIS WHERE SOUTHWEST WINDS ACROSS THE SC COASTAL WATERS CONVERGE WITH SOUTH WINDS CLOSER TO THE GULF STREAM. THIS CONVECTIVE ACTIVITY SHOULD BECOME MORE ISOLATED IN NATURE TOWARD DAYBREAK...BUT THE REMNANT CONVERGENCE AXIS MAY BECOME ACTIVE AGAIN BY LATE MORNING AS THE DEVELOPING SEABREEZE CIRCULATION CREATES ADDITIONAL CONVERGENCE IN THE LOW LEVELS. BY EARLY AFTERNOON WE SHOULD HAVE A DEVELOPING FIELD OF SCATTERED SHOWERS ACROSS MOST OF THE AREA EAST OF I-95 AND WEST OF THE BEACHES. AS THE SEABREEZE MAKES GOOD PROGRESS INLAND THIS AFTERNOON EXPECT CLEARING CONDITIONS WITHIN 20 MILES OF THE COAST...BUT SHOWER AND T-STORM CHANCES WILL INCREASE TO 30-40 PERCENT WEST OF THE SEABREEZE BOUNDARY IN A MODERATELY UNSTABLE AND COMPLETELY UNCAPPED AIRMASS. 850 MB TEMPS IN THE +15C TO +17C RANGE WILL SUPPORT TEMPERATURES IN THE MID 80S INLAND TODAY...WITH LOWER 80S CLOSER TO THE COAST. SOUTHWESTERLY WINDS WILL INCREASE ABOVE THE SURFACE TONIGHT AS A MID-LATITUDE STORM SYSTEM SWEEPS EAST INTO THE GREAT LAKES. A WEAK VORTICITY MAXIMUM LOCATED ACROSS GEORGIA THIS EVENING WILL MOVE EASTWARD AND SHOULD SUSTAIN ISOLATED TO SCATTERED SHOWER AND T-STORM POTENTIAL THROUGH THE NIGHT ACROSS THE EASTERN CAROLINAS. WHILE THE SC PEE DEE REGION WILL BE THE CLOSEST GEOGRAPHICALLY TO THE INCOMING VORT ALOFT...PRECIP CHANCES MAY ACTUALLY BECOME GREATEST IN THE WILMINGTON AREA AS MODELS ARE INSISTENT THAT A BLOB OF GULF STREAM CONVECTION WILL MOVE NORTH INTO THE CAPE FEAR REGION OVERNIGHT. LOWS SHOULD FALL TO 66-70...WARMEST AT THE BEACHES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...THIS PERIOD WILL BE HIGHLIGHTED BY THE EVOLUTION OF A RATHER DEEP MID-LEVEL TROF THAT WILL DOMINATE THE WEATHER ACROSS THE FA BY THE END OF THIS PERIOD. AT THE BEGINNING OF THE SHORT TERM...THE AMPLIFYING UPPER TROF IS PROGGED TO BE JUST EAST OF THE MISSISSIPPI RIVER...AND BY LATE FRIDAY NIGHT ITS NORTH TO SOUTH TROF AXIS WILL HAVE MOVED JUST OFF THE NORTH AND SOUTH CAROLINA COASTS...VIA NAM AND GFS MODELS. MODELS AT TIMES HAVE TRIED TO MAKE THIS AN AMPLIFIED FULL LATITUDE TROF BUT INDIVIDUAL VORTS/IMPULSES ROTATING THROUGH THIS UPPER FEATURE...ARE PROGGED TO MOVE AT DIFFERENT SPEEDS AND THUS PREVENTING THE CARVING OF A TRUE FULL LATITUDE TROF. ONE OF THE STRONGER VORTS IS PROGGED TO TRACK ACROSS THE FA FRIDAY AFTERNOON/EVENING AS DYNAMICS FROM THIS FEATURE AND COLDER TEMPS ALOFT PROVIDE ENOUGH INSTABILITY FOR ISOLATED CONVECTION. AT THE SURFACE...WESTERN ATLANTIC RIDGING WILL CONTINUE ACROSS THE FA EARLY THURSDAY. A PRE-FRONTAL OR LEE SIDE TROF ORIENTED N-S WILL DEVELOP ACROSS THE WEST-CENTRAL CAROLINAS AND BECOME THE FOCUS FOR CONVECTION DEVELOPMENT AS IT SLOWLY PROGRESSES EASTWARD. IN ADDITION MID-DAY/AFTERNOON DIURNALLY INDUCED CONVECTION WILL BREAK OUT ACROSS THE COASTAL PORTIONS OF THE ILM CWA. WILL INDICATE 50 POPS INLAND...WITH 30-40 CLOSER TO THE COAST DURING THE DAY THURSDAY. FOR THURSDAY NIGHT...THE APPROACHING COLD FRONT WILL BECOME THE PRIMARY FORCE FOR INDUCING CONVECTION. HOWEVER...THE SUB-TROPICAL/TROPICAL MOISTURE FEED WILL HAVE BEEN PUSHED OFFSHORE AND NO LONGER THE PRIMARY SOURCE. THINKING IS THAT ENOUGH MOISTURE WILL REMAIN FOR ADDITIONAL CONVECTION TO FIRE AHEAD OF THE COLD FRONT...DEPENDING HOW MUCH THE ATM IS ABLE TO DE-STABILIZE FROM THE CONVECTION THAT DEVELOPED EARLIER IN THE DAY. AS A RESULT...WILL HIGHLIGHT 40-50 POPS IN THE EVENING AND SLOWLY DROP THEM TO SLIGHT CHANCE OVERNIGHT. MODELS AFTER MIDNIGHT FRIDAY...DIVERGE FROM ONE ANOTHER WITH RESPECT TO THEIR SOLUTIONS RELATED TO THE TIMING AND PLACEMENT OF THE COLD FRONT. FOR EXAMPLE THE NAM AND CANADIAN HAVE THE FRONT OFF THE CAROLINA COASTS BY DAYBREAK FRI...WHEREAS THE GFS LAGS BEHIND AND ONLY HAS IT PROGRESSING THROUGH THE COASTAL CAROLINAS BY DAYBREAK FRI. WILL LEAN TOWARD THE SLIGHTLY SLOWER PROGRESSION OF THE CFP. POST FRONTAL DRIER AIR FINALLY ADVECTS ACROSS THE FA DURING THE DAY FRI. CANADIAN HIGH PRESSURE WILL FINALLY PROVIDE RELIEF FROM THE HUMID SUBTROPICAL/TROPICAL AIR MASS THAT AFFECTED THE FA FOR MUCH OF THIS WEEK. AS FOR MAX/MIN TEMPS...A RANGE OF 80 TO 85 FOR HIGHS THU...SIMILAR TO WHAT THE NAM/GFS MOS GUIDANCE SHOWS. THE COLD AIR ADVECTION BEHIND THE CFP WILL LAG BEHIND...AND BE OFFSET BY A DOWNSLOPE TRAJECTORY IN THE WIND FIELDS. AS A RESULT...HAVE GONE ABOVE GUIDANCE FOR FRIDAYS HIGHS WITH THE COASTAL COUNTIES LIKELY TO BE WARMER THAN INLAND. A COMPROMISED MOS GUIDANCE MIN FORECAST WAS USED. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...FOR SATURDAY THRU MONDAY MID LEVEL FEATURES REMAIN RELATIVELY UNCHANGED WITH THE TROF AXIS ASSOCIATED WITH THE UPPER TROF HAVING ONLY PROGRESSED JUST OFF THE EAST COAST. THE CENTRAL U.S. WILL BE HIGHLIGHTED BY AN UPPER RIDGE WITH ITS AXIS RUNNING N-S ALONG THE MISSISSIPPI RIVER. BY TUESDAY...THE EUROPEAN FLATTENS THIS RIDGE WHEREAS THE GFS PROGRESSES IT EASTWARD AND MAINTAINING ITS IDENTITY. PREFERRED THE GFS SOLUTION AT THIS POINT. AT THE SFC...CANADIAN HIGH PRESSURE TO RIDGE ACROSS THE FA SATURDAY. ITS CENTER IS PROGGED TO BREAK APART BY SUNDAY...WITH THE SOUTHERN EXTENT OF ITS CENTER MOVING ACROSS AND OFFSHORE FROM THE CAROLINAS MONDAY AND TUESDAY. SUBSIDENCE ALOFT WILL KEEP A LID ON THE DIURNALLY DRIVEN CU FROM DEVELOPING IN THE VERTICAL. THEREFORE NO POPS THROUGH SUNDAY. FOR LATE SUNDAY NIGHT THRU TUESDAY...MODELS ARE HINTING AT A BACK-DOOR COLD FRONT DROPPING SOUTHWARD...AND BECOMING STATIONARY JUST NORTH OF THE FA. THIS MAY BECOME AN AID TO POSSIBLE MCS/MCC THAT DEVELOP WELL UPSTREAM MON AND TUE...WHICH WILL FOLLOW THE NW-SE UPPER FLOW. TOO FAR OUT IN TIME TO PREDICT THEIR TIMING...HOWEVER ENOUGH OF A POSSIBILITY TO PLACE A LOW CHANCE POP IN THE GOING FORECAST. FOR THIS UPCOMING MEMORIAL DAY WEEKEND...SATURDAY THROUGH MONDAY MORNING TEMPS ACROSS THE FA WILL RUN 5 TO 10 DEGREES BELOW NORMAL...ESPECIALLY WITH OVERNIGHT LOWS. FOR MONDAY THRU TUESDAY...WILL BE LOOKING AT NEAR NORMAL TEMPS. IF THE BACK-DOOR COLD FRONT DROPS FURTHER SOUTH THAN ANTICIPATED...THE NW FLOW AHEAD OF IT COULD PUSH TEMPS WELL INTO THE 80S TO AROUND 90...MUCH HIGHER THAN THE CURRENT MOS GUIDANCE. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...A BIT LESS DEEP MOISTURE TODAY WITH MAINLY SOUTHERLY FLOW. A LOW LCL INDICATES A MVFR CEILING COULD FORM AN HOUR OR SO AFTER SUNRISE. HRRR MODEL INDICATES AN EARLY START TO CONVECTION ALONG THE SEA BREEZE TODAY...WITH SHOWERS LIKELY NOT AS STRONG DUE TO LACK OF MOISTURE. MOST OF THE ACTIVITY WILL ACTUALLY BE BETWEEN THE INLAND AND COASTAL TERMINALS...NEARING THE INLAND TERMINALS BY 18Z. SOUTHERLY FLOW WILL BE A BIT GUSTY THIS AFTERNOON...DIMINISHING DIURNALLY THIS EVENING. WILL REEVALUATE BACK END OF TAFS ON THE NEXT MODEL RUN AS ANOTHER SLUG OF MOISTURE ADVECTS IN FROM THE SOUTH. EXTENDED OUTLOOK...SHOWERS/T-STORMS POSSIBLE THURSDAY THROUGH EARLY FRIDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 700 AM WEDNESDAY...ISOLATED SHOWERS MAY CONTINUE THROUGH THE MORNING HOURS BUT SHOULD DISSIPATE WITH THE AFTERNOON SEABREEZE CIRCULATION. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... BERMUDA HIGH PRESSURE WILL MOVE LITTLE THROUGH TONIGHT...CONTINUING TO PUMP AIR FROM THE CARIBBEAN NORTHWARD ACROSS THE CAROLINA COASTAL WATERS. LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES...TOO FAR AWAY FOR ANY DIRECT AFFECTS JUST YET. A TYPICAL SUMMER/TROPICAL WEATHER REGIME IS EXPECTED WITH SCATTERED SHOWERS AND THUNDERSTORMS OVER THE COASTAL WATERS ENDING THIS MORNING...THEN REDEVELOPING TONIGHT. MODELS ARE ACTUALLY QUITE INSISTENT THAT AT LEAST ONE CONCENTRATED BATCH OF CONVECTION COULD ROLL IN OFF THE GULF STREAM OVERNIGHT AND TOWARD COASTAL NORTH CAROLINA. OUTSIDE OF ANY SHOWER AND THUNDERSTORM ACTIVITY...SOUTH WINDS SHOULD AVERAGE 10-15 KNOTS WITH 3-4 FT SEAS. DOMINANT WAVE PERIODS AT THE FRYING PAN SHOALS BUOY ARE 6 SECONDS...WITH YESTERDAY`S 10 SECOND EASTERLY SWELL HARDLY REGISTERING ANYMORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WESTERN ATLANTIC RIDGING WILL PROVIDE A RATHER SOLID 15 KT SOUTHERLY FLOW DURING THU...BECOMING SW LATE THU AFTERNOON AND NIGHT. THE SFC PG WILL TIGHTEN BETWEEN THE APPROACHING COLD FRONT AND THE WESTERN ATLANTIC HIGH CENTERED WELL OFFSHORE FROM THE SE U.S.COAST. COULD SEE 15 TO 20 KT WITH SOME HIGHER GUSTS. CFP SLATED FOR AFTER DAYBREAK FRI...WITH WINDS VEERING TO W TO NW 10 TO 15 KT...INCREASING TO 15 TO 25 KT FRIDAY NIGHT DUE TO COLD AIR ADVECTION COMBINED WITH A TIGHTENED SFC PG. SIGNIFICANT SEAS WILL RANGE FROM 2 TO 4 FT THU...BUILDING TO 3 TO 5 FT LATE THU THROUGH EARLY FRI. TEMPORARILY DROPPING BACK TO 2 TO 4 FT DURING FRIDAY...THEN BUILDING BACK TO 3 TO 5 FT FRI NIGHT WITH 6 FOOTERS POSSIBLE OUTER WATERS OFF CAPE FEAR. SIG. SEAS WILL PRIMARILY BE DRIVEN BY AN ESE GROUND SWELL AT 8 TO 9 SECOND PERIODS DURING EARLY THU...WITH 4 TO 6 SECOND PERIOD WIND DRIVEN WAVES TO DOMINATE LATE THU THRU FRI NITE. SCEC CONDITIONS POSSIBLE FOR ALL WATERS...WITH A BORDERLINE SCA FOR THE ILM NC WATERS DURING THE INFLUX OF COLD AIR FRI NIGHT. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...POSSIBLE SCEC OR SCA CONDITIONS WILL PEAK DURING EARLY SATURDAY...WITH A DIMINISHING AND SUBSIDING TREND FOR WINDS AND SIGNIFICANT SEAS RESPECTIVELY DURING THE LATTER 2/3RDS OF THIS PERIOD. ALL IN RESPONSE TO THE CENTER OF THE MODERATING CANADIAN HIGH PUSHING ACROSS THE LOCAL WATERS SUNDAY THROUGH SUNDAY NIGHT. WINDS ARE PROGGED TO BECOME VARIABLE IN DIRECTION DURING SUNDAY AND SUNDAY NIGHT AT 10 KT OR LESS. SIGNIFICANT SEAS WILL BE DRIVEN BY LOCALLY PRODUCED SHORT PERIOD WIND DRIVEN WAVES ON SATURDAY...WITH AN 8 TO 9 SECOND PERIOD SMALL EASTERLY SWELL DOMINATING ON SUNDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...DCH/TRA NEAR TERM...TRA SHORT TERM...DCH LONG TERM...DCH AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
650 AM EDT WED MAY 22 2013 .SYNOPSIS... WESTERN ATLANTIC HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE EASTERN CAROLINAS THROUGH EARLY THURSDAY. SHOWERS AND THUNDERSTORMS WILL INCREASE THURSDAY AND THURSDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL CROSS THE REGION FRIDAY MORNING. A MUCH COOLER AND DRIER AIR MASS WILL FOLLOW...COMPLEMENTS OF A CANADIAN HIGH PRESSURE...AND AFFECT THE AREA THIS WEEKEND. THE HIGH WILL SLIDE OFF THE EAST COAST EARLY NEXT WEEK WITH TEMPERATURES REBOUNDING TO NEAR NORMAL...ALONG WITH AN INCREASE IN DIURNALLY DRIVEN CONVECTION. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...THE WEAK UPPER LEVEL SHEAR AXIS THAT HAS BEEN NEARLY STATIONARY ACROSS THE EASTERN CAROLINAS FOR THE PAST TWO DAYS HAS DECAYED AS LIGHT SOUTHERLY FLOW HAS ESTABLISHED ITSELF THROUGHOUT THE 500-700 MB LAYER. ALTHOUGH THE OVERALL AIRMASS REMAINS THE SAME AS YESTERDAY...TRIGGERS FOR TODAY`S CONVECTION WILL BE SURFACE BOUNDARIES ONLY. EARLY MORNING CONVECTION MOVING ONSHORE ACROSS OAK ISLAND THROUGH WILMINGTON IS ASSOCIATED WITH A LOW-LEVEL CONVERGENCE AXIS WHERE SOUTHWEST WINDS ACROSS THE SC COASTAL WATERS CONVERGE WITH SOUTH WINDS CLOSER TO THE GULF STREAM. THIS CONVECTIVE ACTIVITY SHOULD BECOME MORE ISOLATED IN NATURE TOWARD DAYBREAK...BUT THE REMNANT CONVERGENCE AXIS MAY BECOME ACTIVE AGAIN BY LATE MORNING AS THE DEVELOPING SEABREEZE CIRCULATION CREATES ADDITIONAL CONVERGENCE IN THE LOW LEVELS. BY EARLY AFTERNOON WE SHOULD HAVE A DEVELOPING FIELD OF SCATTERED SHOWERS ACROSS MOST OF THE AREA EAST OF I-95 AND WEST OF THE BEACHES. AS THE SEABREEZE MAKES GOOD PROGRESS INLAND THIS AFTERNOON EXPECT CLEARING CONDITIONS WITHIN 20 MILES OF THE COAST...BUT SHOWER AND T-STORM CHANCES WILL INCREASE TO 30-40 PERCENT WEST OF THE SEABREEZE BOUNDARY IN A MODERATELY UNSTABLE AND COMPLETELY UNCAPPED AIRMASS. 850 MB TEMPS IN THE +15C TO +17C RANGE WILL SUPPORT TEMPERATURES IN THE MID 80S INLAND TODAY...WITH LOWER 80S CLOSER TO THE COAST. SOUTHWESTERLY WINDS WILL INCREASE ABOVE THE SURFACE TONIGHT AS A MID-LATITUDE STORM SYSTEM SWEEPS EAST INTO THE GREAT LAKES. A WEAK VORTICITY MAXIMUM LOCATED ACROSS GEORGIA THIS EVENING WILL MOVE EASTWARD AND SHOULD SUSTAIN ISOLATED TO SCATTERED SHOWER AND T-STORM POTENTIAL THROUGH THE NIGHT ACROSS THE EASTERN CAROLINAS. WHILE THE SC PEE DEE REGION WILL BE THE CLOSEST GEOGRAPHICALLY TO THE INCOMING VORT ALOFT...PRECIP CHANCES MAY ACTUALLY BECOME GREATEST IN THE WILMINGTON AREA AS MODELS ARE INSISTENT THAT A BLOB OF GULF STREAM CONVECTION WILL MOVE NORTH INTO THE CAPE FEAR REGION OVERNIGHT. LOWS SHOULD FALL TO 66-70...WARMEST AT THE BEACHES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...THIS PERIOD WILL BE HIGHLIGHTED BY THE EVOLUTION OF A RATHER DEEP MID-LEVEL TROF THAT WILL DOMINATE THE WEATHER ACROSS THE FA BY THE END OF THIS PERIOD. AT THE BEGINNING OF THE SHORT TERM...THE AMPLIFYING UPPER TROF IS PROGGED TO BE JUST EAST OF THE MISSISSIPPI RIVER...AND BY LATE FRIDAY NIGHT ITS NORTH TO SOUTH TROF AXIS WILL HAVE MOVED JUST OFF THE NORTH AND SOUTH CAROLINA COASTS...VIA NAM AND GFS MODELS. MODELS AT TIMES HAVE TRIED TO MAKE THIS AN AMPLIFIED FULL LATITUDE TROF BUT INDIVIDUAL VORTS/IMPULSES ROTATING THROUGH THIS UPPER FEATURE...ARE PROGGED TO MOVE AT DIFFERENT SPEEDS AND THUS PREVENTING THE CARVING OF A TRUE FULL LATITUDE TROF. ONE OF THE STRONGER VORTS IS PROGGED TO TRACK ACROSS THE FA FRIDAY AFTERNOON/EVENING AS DYNAMICS FROM THIS FEATURE AND COLDER TEMPS ALOFT PROVIDE ENOUGH INSTABILITY FOR ISOLATED CONVECTION. AT THE SURFACE...WESTERN ATLANTIC RIDGING WILL CONTINUE ACROSS THE FA EARLY THURSDAY. A PRE-FRONTAL OR LEE SIDE TROF ORIENTED N-S WILL DEVELOP ACROSS THE WEST-CENTRAL CAROLINAS AND BECOME THE FOCUS FOR CONVECTION DEVELOPMENT AS IT SLOWLY PROGRESSES EASTWARD. IN ADDITION ...MID-DAY/AFTERNOON DIURNALLY INDUCED CONVECTION WILL BREAK OUT ACROSS THE COASTAL PORTIONS OF THE ILM CWA. WILL INDICATE 50 POPS INLAND...WITH 30-40 CLOSER TO THE COAST DURING THE DAY THURSDAY. FOR THURSDAY NIGHT...THE APPROACHING COLD FRONT WILL BECOME THE PRIMARY FORCE FOR INDUCING CONVECTION. HOWEVER...THE SUB-TROPICAL/TROPICAL MOISTURE FEED WILL HAVE BEEN PUSHED OFFSHORE AND NO LONGER THE PRIMARY SOURCE. THINKING IS THAT ENOUGH MOISTURE WILL REMAIN FOR ADDITIONAL CONVECTION TO FIRE AHEAD OF THE COLD FRONT...DEPENDING HOW MUCH THE ATM IS ABLE TO DE-STABILIZE FROM THE CONVECTION THAT DEVELOPED EARLIER IN THE DAY. AS A RESULT...WILL HIGHLIGHT 40-50 POPS IN THE EVENING AND SLOWLY DROP THEM TO SLIGHT CHANCE OVERNIGHT. MODELS AFTER MIDNIGHT FRIDAY...DIVERGE FROM ONE ANOTHER WITH RESPECT TO THEIR SOLUTIONS RELATED TO THE TIMING AND PLACEMENT OF THE COLD FRONT. FOR EXAMPLE THE NAM AND CANADIAN HAVE THE FRONT OFF THE CAROLINA COASTS BY DAYBREAK FRI...WHEREAS THE GFS LAGS BEHIND AND ONLY HAS IT PROGRESSING THROUGH THE COASTAL CAROLINAS BY DAYBREAK FRI. WILL LEAN TOWARD THE SLIGHTLY SLOWER PROGRESSION OF THE CFP. POST FRONTAL DRIER AIR FINALLY ADVECTS ACROSS THE FA DURING THE DAY FRI. CANADIAN HIGH PRESSURE WILL FINALLY PROVIDE RELIEF FROM THE HUMID SUBTROPICAL/TROPICAL AIR MASS THAT AFFECTED THE FA FOR MUCH OF THIS WEEK. AS FOR MAX/MIN TEMPS...A RANGE OF 80 TO 85 FOR HIGHS THU...SIMILAR TO WHAT THE NAM/GFS MOS GUIDANCE SHOWS. THE COLD AIR ADVECTION BEHIND THE CFP WILL LAG BEHIND...AND BE OFFSET BY A DOWNSLOPE TRAJECTORY IN THE WIND FIELDS. AS A RESULT...HAVE GONE ABOVE GUIDANCE FOR FRIDAYS HIGHS WITH THE COASTAL COUNTIES LIKELY TO BE WARMER THAN INLAND. A COMPROMISED MOS GUIDANCE MIN FORECAST WAS USED. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...FOR SATURDAY THRU MONDAY MID LEVEL FEATURES REMAIN RELATIVELY UNCHANGED WITH THE TROF AXIS ASSOCIATED WITH THE UPPER TROF HAVING ONLY PROGRESSED JUST OFF THE EAST COAST. THE CENTRAL U.S. WILL BE HIGHLIGHTED BY AN UPPER RIDGE WITH ITS AXIS RUNNING N-S ALONG THE MISSISSIPPI RIVER. BY TUESDAY...THE EUROPEAN FLATTENS THIS RIDGE WHEREAS THE GFS PROGRESSES IT EASTWARD AND MAINTAINING ITS IDENTITY. PREFERRED THE GFS SOLUTION AT THIS POINT. AT THE SFC...CANADIAN HIGH PRESSURE TO RIDGE ACROSS THE FA SATURDAY. ITS CENTER IS PROGGED TO BREAK APART BY SUNDAY...WITH THE SOUTHERN EXTENT OF ITS CENTER MOVING ACROSS AND OFFSHORE FROM THE CAROLINAS MONDAY AND TUESDAY. SUBSIDENCE ALOFT WILL KEEP A LID ON THE DIURNALLY DRIVEN CU FROM DEVELOPING IN THE VERTICAL. THEREFORE NO POPS THROUGH SUNDAY. FOR LATE SUNDAY NIGHT THRU TUESDAY...MODELS ARE HINTING AT A BACK-DOOR COLD FRONT DROPPING SOUTHWARD...AND BECOMING STATIONARY JUST NORTH OF THE FA. THIS MAY BECOME AN AID TO POSSIBLE MCS/MCC THAT DEVELOP WELL UPSTREAM MON AND TUE...WHICH WILL FOLLOW THE NW-SE UPPER FLOW. TOO FAR OUT IN TIME TO PREDICT THEIR TIMING...HOWEVER ENOUGH OF A POSSIBILITY TO PLACE A LOW CHANCE POP IN THE GOING FORECAST. FOR THIS UPCOMING MEMORIAL DAY WEEKEND...SATURDAY THROUGH MONDAY MORNING TEMPS ACROSS THE FA WILL RUN 5 TO 10 DEGREES BELOW NORMAL...ESPECIALLY WITH OVERNIGHT LOWS. FOR MONDAY THRU TUESDAY...WILL BE LOOKING AT NEAR NORMAL TEMPS. IF THE BACK-DOOR COLD FRONT DROPS FURTHER SOUTH THAN ANTICIPATED...THE NW FLOW AHEAD OF IT COULD PUSH TEMPS WELL INTO THE 80S TO AROUND 90...MUCH HIGHER THAN THE CURRENT MOS GUIDANCE. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...A BIT LESS DEEP MOISTURE TODAY WITH MAINLY SOUTHERLY FLOW. A LOW LCL INDICATES A MVFR CEILING COULD FORM AN HOUR OR SO AFTER SUNRISE. HRRR MODEL INDICATES AN EARLY START TO CONVECTION ALONG THE SEA BREEZE TODAY...WITH SHOWERS LIKELY NOT AS STRONG DUE TO LACK OF MOISTURE. MOST OF THE ACTIVITY WILL ACTUALLY BE BETWEEN THE INLAND AND COASTAL TERMINALS...NEARING THE INLAND TERMINALS BY 18Z. SOUTHERLY FLOW WILL BE A BIT GUSTY THIS AFTERNOON...DIMINISHING DIURNALLY THIS EVENING. WILL REEVALUATE BACK END OF TAFS ON THE NEXT MODEL RUN AS ANOTHER SLUG OF MOISTURE ADVECTS IN FROM THE SOUTH. EXTENDED OUTLOOK...SHOWERS/T-STORMS POSSIBLE THURSDAY THROUGH EARLY FRIDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...BERMUDA HIGH PRESSURE WILL MOVE LITTLE THROUGH TONIGHT...CONTINUING TO PUMP AIR FROM THE CARIBBEAN NORTHWARD ACROSS THE CAROLINA COASTAL WATERS. LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES...TOO FAR AWAY FOR ANY DIRECT AFFECTS JUST YET. A TYPICAL SUMMER/TROPICAL WEATHER REGIME IS EXPECTED WITH SCATTERED SHOWERS AND THUNDERSTORMS OVER THE COASTAL WATERS ENDING THIS MORNING...THEN REDEVELOPING TONIGHT. MODELS ARE ACTUALLY QUITE INSISTENT THAT AT LEAST ONE CONCENTRATED BATCH OF CONVECTION COULD ROLL IN OFF THE GULF STREAM OVERNIGHT AND TOWARD COASTAL NORTH CAROLINA. OUTSIDE OF ANY SHOWER AND THUNDERSTORM ACTIVITY...SOUTH WINDS SHOULD AVERAGE 10-15 KNOTS WITH 3-4 FT SEAS. DOMINANT WAVE PERIODS AT THE FRYING PAN SHOALS BUOY ARE 6 SECONDS...WITH YESTERDAY`S 10 SECOND EASTERLY SWELL HARDLY REGISTERING ANYMORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WESTERN ATLANTIC RIDGING WILL PROVIDE A RATHER SOLID 15 KT SOUTHERLY FLOW DURING THU...BECOMING SW LATE THU AFTERNOON AND NIGHT. THE SFC PG WILL TIGHTEN BETWEEN THE APPROACHING COLD FRONT AND THE WESTERN ATLANTIC HIGH CENTERED WELL OFFSHORE FROM THE SE U.S.COAST. COULD SEE 15 TO 20 KT WITH SOME HIGHER GUSTS. CFP SLATED FOR AFTER DAYBREAK FRI...WITH WINDS VEERING TO W TO NW 10 TO 15 KT...INCREASING TO 15 TO 25 KT FRIDAY NIGHT DUE TO COLD AIR ADVECTION COMBINED WITH A TIGHTENED SFC PG. SIGNIFICANT SEAS WILL RANGE FROM 2 TO 4 FT THU...BUILDING TO 3 TO 5 FT LATE THU THROUGH EARLY FRI. TEMPORARILY DROPPING BACK TO 2 TO 4 FT DURING FRIDAY...THEN BUILDING BACK TO 3 TO 5 FT FRI NIGHT WITH 6 FOOTERS POSSIBLE OUTER WATERS OFF CAPE FEAR. SIG. SEAS WILL PRIMARILY BE DRIVEN BY AN ESE GROUND SWELL AT 8 TO 9 SECOND PERIODS DURING EARLY THU...WITH 4 TO 6 SECOND PERIOD WIND DRIVEN WAVES TO DOMINATE LATE THU THRU FRI NITE. SCEC CONDITIONS POSSIBLE FOR ALL WATERS...WITH A BORDERLINE SCA FOR THE ILM NC WATERS DURING THE INFLUX OF COLD AIR FRI NIGHT. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...POSSIBLE SCEC OR SCA CONDITIONS WILL PEAK DURING EARLY SATURDAY...WITH A DIMINISHING AND SUBSIDING TREND FOR WINDS AND SIGNIFICANT SEAS RESPECTIVELY DURING THE LATTER 2/3RDS OF THIS PERIOD. ALL IN RESPONSE TO THE CENTER OF THE MODERATING CANADIAN HIGH PUSHING ACROSS THE LOCAL WATERS SUNDAY THROUGH SUNDAY NIGHT. WINDS ARE PROGGED TO BECOME VARIABLE IN DIRECTION DURING SUNDAY AND SUNDAY NIGHT AT 10 KT OR LESS. SIGNIFICANT SEAS WILL BE DRIVEN BY LOCALLY PRODUCED SHORT PERIOD WIND DRIVEN WAVES ON SATURDAY...WITH AN 8 TO 9 SECOND PERIOD SMALL EASTERLY SWELL DOMINATING ON SUNDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...DCH NEAR TERM...TRA SHORT TERM...DCH LONG TERM...DCH AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
136 AM EDT WED MAY 22 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE EASTERN CAROLINAS. SHOWERS AND THUNDERSTORMS WILL INCREASE ON THURSDAY AHEAD OF A COLD FRONT THAT WILL CROSS THE REGION EARLY FRIDAY. COOLER AND DRIER WEATHER WILL FOLLOW FOR THE WEEKEND AND EARLY NEXT WEEK AS HIGH PRESSURE MOVES OFF THE EAST COAST. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 130 AM THURSDAY...ONLY CHANGES TO THE FORECAST WERE TO INCREASE CLOUD COVER INLAND GIVEN THE RECENT DEVELOPMENT OF PLENTY OF LOW STRATUS FROM THE PEE DEE REGION AS FAR EAST AS WHITEVILLE AND ELIZABETHTOWN. THE LAST FOUR RUNS OF THE HRRR ARE INSISTENT THAT SCATTERED SHOWERS WILL DEVELOP JUST WEST OF I-95 IN THE NEXT FEW HOURS. THIS LINES UP NICELY WITH WHAT`S LEFT OF THE 700-500 MB SHEAR AXIS THAT HAS DEVELOPED CONVECTION EACH OF THE LAST TWO NIGHTS. I HAVE ONLY INCLUDED A TINY 15-20 PERCENT POP MAINLY FOR THE DARLINGTON-BENNETTSVILLE CORRIDOR. OTHERWISE NO SIGNIFICANT CHANGES. PREVIOUS DISCUSSION FROM 1000 PM FOLLOWS... THE DIURNALLY DRIVEN CONVECTION HAS ENDED ACROSS THE AREA WITH THE LOSS OF HEATING. SOME OF THE HIGHEST RESOLUTION MODELS ARE INDICATING A FEW SHOWERS MAY DEVELOP AFTER MIDNIGHT. WE DO EXPECT CONVECTION TO DEVELOP/EXPAND ACROSS THE WATERS AS A WEAK UPPER LEVEL DISTURBANCE PASSES UP THE COAST...TO OUR E. IT IS POSSIBLE THAT THE CONVECTION MAY DEVELOP/EXPAND ONTO THE IMMEDIATE COAST VERY LATE TONIGHT...BUT THE RISK REMAINS SMALL. CONSIDERABLE EVE CLOUD COVER WILL CONTINUE TO VERY SLOWLY DIMINISH DURING THE LATE NIGHT. NIGHTTIME TEMPS WILL AGAIN BE ABOVE NORMAL...MID AND UPPER 60S. THE LAST TIME MINIMUMS WERE BELOW NORMAL WAS ON MAY 15TH. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...DEEP SOUTH TO SOUTHWEST FLOW FOR MUCH OF THE PERIOD WILL CONTINUE TO PUMP PLENTY OF GULF MOISTURE INTO THE REGION. BERMUDA HIGH AND MID LEVEL RIDING OVER THE WESTERN ATLANTIC BRIEFLY EXPAND WEST WED. INCREASE IN MID LEVEL SUBSIDENCE WILL LIMIT COVERAGE OF AFTERNOON SHOWERS AND THUNDERSTORMS. DIURNAL INSTABILITY ALONG WITH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES AND CONVERGENCE ALONG THE SEA BREEZE HOWEVER SUGGEST POP WILL NOT BE ZERO. GIVEN THE LIMITING FACTORS SLIGHT CHANCE TO LOW CHANCE SEEMS REASONABLE WITH INLAND SC FAVORED. WORTH NOTING THAT THE 12Z NAM IS NOT AS AGGRESSIVE WITH THE BUILDING RIDGE AND IS SLOWER TO EXIT THE SHORTWAVE REMNANTS. DISCOUNTING THIS SCENARIO FOR NOW AS IT IS A SIGNIFICANT CHANGE FROM PREVIOUS SOLUTIONS BUT SHOULD IT VERIFY POP WOULD NEED TO BE MUCH HIGHER. MID LEVEL RIDGE QUICKLY WEAKENS THU WITH 5H TROUGH APPROACHING FROM THE WEST. WHILE THE LOCAL ENVIRONMENT REMAINS RELATIVELY UNCHANGED...DEEP SOUTHERLY FLOW PUSHES PWATS NEAR 1.8 INCHES...THE LOSS OF SUBSIDENCE WILL RESULT IN A SIGNIFICANT INCREASE IN STORM COVERAGE. IN ADDITION ANOTHER STRETCHED SHORTWAVE WILL MOVE INTO THE AREA FROM THE BAHAMAS EARLY THU. PVA AHEAD OF IT REACHES THE AREA LATE WED NIGHT OR THU MORNING AND SHOULD ENHANCE CONVECTION. AS HAS BEEN THE CASE OVER THE PAST FEW DAYS THE ENVIRONMENT IS NOT SUPPORTIVE OF SEVERE WEATHER. HOWEVER DEEP WARM LAYER AND RELATIVELY SLOW STORM MOTION WITH POTENTIAL FOR TRAINING STORMS WILL KEEP THE FLOOD THREAT ELEVATED...ESPECIALLY IN AREAS THAT HAVE ALREADY RECEIVED SIGNIFICANT RAINFALL THE LAST FEW DAYS. CONVECTION WILL BE WINDING DOWN THU EVENING AS DRY AIR JUST AHEAD OF THE 5H TROUGH AXIS AND SURFACE COLD FRONT STARTS TO MOVE IN. COLD FRONT IS SLOW TO CROSS THE AREA...NOT REACHING THE COAST UNTIL CLOSE TO THE END OF THE PERIOD...BUT ALOFT WESTERLY FLOW STARTS DEVELOPING BEFORE 00Z FRI. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE CLIMO...WITH NUMBERS TEMPERED BY CLOUDS IN SOME AREAS WHILE LOWS CONTINUE TO RUN ABOVE CLIMO. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...CHANGE IN AIR MASS EXPECTED ON FRIDAY AS COLD FRONT MAKES ITS WAY OFF SHORE AND COOL CANADIAN HIGH PRESSURE BUILDS IN. EXPECT COOLER AND DRIER AIR TO MAKE ITS WAY INTO THE COASTAL CAROLINAS IN DEEP WEST TO NORTHWEST FLOW. PCP WATER VALUES UP ABOVE 1.5 INCHES OVER THE DAYS LEADING UP TO FRIDAY WILL DROP OUT TO LESS THAN AN INCH BY FRI AFTN AND BE DOWN TO LESS THAN A HALF INCH BY SAT MORNING AS ATMOSPHERIC COLUMN DRIES OUT. THEREFORE DO NOT EXPECT ANY PCP THROUGH THE WEEKEND IN A RELATIVELY COOLER AND DRIER NORTHERLY FLOW. AS FOR TEMPS...FRIDAY SHOULD MAKE IT INTO THE 80S IN MOST PLACES BUT WILL FEEL COOLER AND DRIER BY THE END OF THE DAY. THE 850 TEMPS DROP FROM CLOSE TO 15C PREVIOUS DAYS DOWN TO 8 TO 10C THROUGH THE WEEKEND. SATURDAY AND SUNDAY TEMPS WILL REMAIN BETWEEN 75 TO 80 MOST PLACES WITH MUCH LOWER DEWPOINTS REACHING DOWN INTO THE 40S INLAND TO AROUND 50 ALONG THE COAST AS COMPARED TO 65 THE PREVIOUS DAYS. WILL ALSO SEE MUCH GREATER DIURNAL SWINGS DUE TO THE DRY AIR MASS IN PLACE. OVERNIGHT LOWS WILL REACH DOWN TO THE LOWER END OF THE 50S BOTH FRI NIGHT AND SAT NIGHT IN COOL ADVECTION AND BETTER RADIATIONAL COOLING SAT NIGHT AS HIGH PRESSURE SHIFTS OVERHEAD. BY LATE SUNDAY INTO MONDAY THE HIGH PRESSURE WILL SHIFT OFF SHORE GIVING WAY TO A WARMER MOISTER RETURN FLOW THROUGH EARLY NEXT WEEK. THEREFORE WILL SEE A WARMING TREND. THE GFS SHOWS A WEAK COLD FRONT DROPPING SOUTH INTO NORTH CAROLINA LATE MONDAY INTO TUES. THEREFORE WILL SHOW CLOUDS AND CHC OF PCP BACK IN THE FORECAST HOLDING TO THE NORTH ON MONDAY AND OVER LOCAL AREA BY TUES. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...THROUGH DAYBREAK...RICH LOW LEVEL MOISTURE WILL HELP DEVELOP PATCHES OF LOW STRATUS INLAND...PERIODICALLY AFFECTING THE FLO/LBT AIRPORTS THROUGH 09Z. THE EXPECTATION IS STRATOCUMULUS CLOUDS DEVELOPING JUST ABOVE THE STRATUS AROUND 2000-3000 FT AGL WILL HELP ERODE THE LOWER IFR DECK BY 09Z. AT THE COAST VFR CONDITIONS COULD COME DOWN INTO THE MVFR RANGE AS THE SAME MOISTURE AROUND 2000-3000 FT AGL PRODUCES A SCT-BKN LAYER OF STRATOCUMULUS IN THE NEXT FEW HOURS. LIGHT SOUTH WINDS. AFTER DAYBREAK....ANTICIPATE VFR CONDITIONS WILL PREVAIL WITH SCATTERED TO OCNL BKN CU/TCU DEVELOPING BY LATE MORNING. SFC WINDS FROM THE SOUTH WILL INCREASE TO 10-15 KT WITH HIGHER GUSTS AT CRE/MYR/ILM WITH THE AFTERNOON SEABREEZE. ISOLATED SHRA/TSRA ARE POSSIBLE INLAND...BUT PROBS ARE TOO LOW TO INCLUDE IN THE TAF AT THIS TIME. EVENING HOURS...VFR WITH DIMINISHING WINDS. EXTENDED OUTLOOK...SLIGHT CHC OF SHOWERS WEDNESDAY. SHOWERS/T-STORMS POSSIBLE THURSDAY THROUGH EARLY FRIDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM THURSDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS DISCUSSION FROM 1000 PM FOLLOWS... A BERMUDA RIDGE WILL CONTINUE TO DOMINATE THE WATERS AS A WEAK UPPER LEVEL DISTURBANCE MOVES UP THE COAST...TO OUR E. S TO SW WINDS WILL BE AROUND 10 KT OR LESS FOR THE REMAINDER OF THE NIGHT. SEAS WILL BE NEAR 3 FT. A WEAK 7 TO 8 SECOND SE SWELL WILL REMAIN. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...BERMUDA HIGH REMAINS IN CONTROL WED BEFORE RETREATING EAST THU AHEAD OF A COLD FRONT EXPECTED TO CROSS THE WATERS LATE THU NIGHT. WED BERMUDA HIGH MAINTAINS SOUTHERLY FLOW WITH SPEEDS OF 10 TO 15 KT RANGE AND SEAS 2 TO 4 FT. WIND SPEEDS INCREASE SLIGHTLY THEN VEER THU INTO THU NIGHT AS THE COLD FRONT APPROACHES FROM THE WEST. WINDS WILL GENERALLY BE 10 TO 15 KT WITH PERIODS OF SUSTAINED 15 KT LIKELY...ESPECIALLY IN THE AFTERNOON. WINDS EVENTUALLY VEER TO WEST LATE THU NIGHT AS FRONT PASSES. SEAS BRIEFLY RISE TO 3 TO 5 FT THU THEN DROP BACK TO 2 TO 4 FT AS PERIOD ENDS. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 PM TUESDAY...COLD FRONT MOVING FARTHER ON FRIDAY AS COOLER AND DRIER CANADIAN HIGH PRESSURE BUILDS IN BEHIND IT THROUGH THE WEEKEND. WINDS WILL VEER AROUND FROM WEST AROUND 10 KTS FRIDAY MORNING...TO NORTH TO NORTHEAST AT 15 TO 20 KTS FRIDAY NIGHT INTO SATURDAY IN COOL SURGE AND TIGHTENED GRADIENT. WINDS WILL LIGHTEN AND CONTINUE TO VEER AS HIGH PRESSURE SHIFTS OVERHEAD ON SUNDAY. SEAS WILL BE ENTIRELY WIND-WAVE DOMINATED BETWEEN 3 AND 5 FT THROUGH FRI INTO SATURDAY. BY LATE SATURDAY INTO SUNDAY...THE SEAS WILL SUBSIDE AND WINDS LIGHTEN AS HIGH SHIFTS CLOSER OVERHEAD. EXPECT SEAS DOWN TO 3 FT OR LESS BY SAT NIGHT INTO SUNDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RJD/TRA SHORT TERM...III LONG TERM...RGZ AVIATION...SGL/TRA
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
125 PM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 125 PM CDT WED MAY 22 2013 CONFINED REMAINING POPS THIS AFTERNOON ALONG AND SOUTHEAST OF A LINE FROM FORMAN TO WAHPETON TO WADENA. LOW STRATUS AND LINGERING LIGHT RAIN SHOWERS WILL CONTINUE TO MOVE SOUTH AND EAST AS THE RESPONSIBLE SURFACE LOW SLIDES INTO NORTHERN ILLINOIS. ADJUSTED SKY AND AND TEMPERATURE GRIDS TO MATCH LATEST OBSERVATIONAL TRENDS. OTHERWISE...NO MAJOR CHANGES TO THIS FORECAST. UPDATE ISSUED AT 1024 AM CDT WED MAY 22 2013 NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE AS THE INHERITED FORECAST IS ON TRACK AND BLENDED TO 15 UTC OBSERVED TRENDS. GIVEN RADAR AND SURFACE OBSERVATIONS...DID INCREASE POPS TO NEAR 100 FOR THIS MORNING ACROSS LAKES COUNTRY...DECREASING THROUGH THE AFTERNOON WITH THE CWA EXPECTED TO BE PRECIPITATION FREE BY 22-00 UTC. THE RAP HAS PERFORMED WELL IN REGARDS TO THE STRATUS SHIELD THE PAST COUPLE OF DAYS AND FOLLOWED ITS LATEST 14 UTC SOLUTION FOR CLOUD COVER. UPDATE ISSUED AT 647 AM CDT WED MAY 22 2013 NORTH TO NORTHEASTERLY WINDS PICKING UP HAVE SCOURED OUT THE FOG THAT WAS STARTING TO FORM OVER OUR NORTHWESTERN COUNTIES...SO REMOVED MENTION FOR THE REST OF THE MORNING. RAIN WILL LINGER OVER THE SOUTHEASTERN COUNTIES FOR A WHILE LONGER THIS MORNING BEFORE DRYING OUT THIS AFTERNOON. CLOUDS WILL DECREASE THROUGHOUT THE DAY. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 330 AM CDT WED MAY 22 2013 UPPER LOW FINALLY BEGINNING TO PULL AWAY FROM THE CWA AS IT WILL SLOWLY MOVE SOUTHEASTWARD INTO IA TODAY. SFC HIGH PRESSURE HAS STARTED TO NOSE DOWN OUT OF CANADA INTO THE NORTHERN PLAINS. MOST OF THE PRECIP HAS MOVED SOUTH OF THE AREA ALTHOUGH A FEW SCATTERED SHOWERS STILL LINGER IN THE SOUTHERN COUNTIES. THE NORTH HAS CLEARED OUT COMPLETELY AND THERE HAS BEEN SOME PATCHY FOG FORMATION AROUND CANDO AND LANGDON. HOWEVER...THERE IS STILL A PRESSURE GRADIENT AND THINK THIS WILL KEEP FOG FROM BECOMING WIDESPREAD AND DENSE. WILL KEEP A CLOSE EYE ON OBS THROUGH THE EARLY MORNING HOURS. SHOWERS AND CLOUDS WILL LINGER OVER THE SOUTHERN COUNTIES FOR MUCH OF THE DAY BEFORE FINALLY CLEARING OUT BY LATE AFTERNOON. THIS WILL KEEP TEMPS COOLER AND AROUND 60 WHILE THE NORTH WILL BE A BIT WARMER. THE SFC HIGH WILL MOVE FURTHER DOWN FROM CANADA INTO THE UPPER MS VALLEY TONIGHT. THIS SHOULD HELP THE NORTHER TIER ALONG WITH EASTERN COUNTIES GET DOWN TO BELOW 40 DEGREES IN SOME AREAS. THURSDAY SHOULD BE QUIET AND A BIT WARMER AS UPPER RIDGING BUILDS OVER THE REGION. WITH SOME DECENT SUNSHINE KEPT HIGHS IN THE 60S TO LOW 70S. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 330 AM CDT WED MAY 22 2013 THURSDAY NIGHT SOUTHEASTERLY WINDS STILL START PICKING UP OVER THE WESTERN COUNTIES AS SFC HIGH PRESSURE OVER MN/WI ALONG WITH A DEVELOPING LOW OVER MT CREATES A DECENT PRESSURE GRADIENT. THE WINDS WILL HELP KEEP THE WESTERN COUNTIES FROM COMPLETELY DECOUPLING AND STAY A BIT WARMER WHILE THE EAST WILL AGAIN DROP TO AROUND 40 DEGREES. SOUTHEASTERLY WINDS WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT AS A LEE TROUGH CONTINUES OVER THE WESTERN PLAINS. MODELS ARE ALL IN FAIRLY DECENT AGREEMENT ON A WEAK SHORTWAVE COMING OVER THE UPPER RIDGE AND SOME DECENT ISENTROPIC LIFT PRODUCING SOME PRECIP FRIDAY AFTERNOON INTO FRIDAY NIGHT. AT THIS POINT THE INSTABILITY SEEMS FAIRLY WEAK WITH SFC BASED CAPE STAYING WEST OF OUR AREA AND ONLY A LITTLE BIT OF ELEVATED CAPE TO WORK WITH. INCLUDED A CHANCE OF SHOWERS WITH ISOLATED THUNDERSTORMS THROUGH FRIDAY NIGHT WITH BEST CHANCES IN OUR WEST. SATURDAY-TUESDAY...00Z MODELS CONTINUE TO SUGGEST THE SYNOPTIC PATTERN WILL BE DOMINATED BY LONGWAVE TROUGHING OVER THE WESTERN US...WITH SOME DEGREE OF MID/UPPER LEVEL RIDGING INTO THE PLAINS DURING MUCH OF THIS PERIOD. A SERIES OF WEAK UPPER LEVEL SHORTWAVE TROUGHS EJECTING OUT OF THE BROADER TROUGH TO THE WEST WILL LEAD TO BOUTS OF SHOWERS OR THUNDERSTORMS ACROSS THE REGION WITHIN THE LOW TO MID-LEVEL WARM AIR ADVECTION ZONE ASSOCIATED WITH THE INDIVIDUAL WAVES. WITH THIS TYPE OF PATTERN...CONFIDENCE IN THE TIMING/PLACEMENT OF INDIVIDUAL WAVES IS LOW...SO CONTINUED TO CARRY SOME POPS FOR MUCH OF THE PERIOD...ALTHOUGH MANY DRY HOURS ARE EXPECTED. THE 00Z GFS/ECMWF SUGGEST A TREND TO A MORE PREDOMINANT ACTIVE SOUTHWEST FLOW PATTERN ACROSS THE PLAINS TOWARDS THE MIDDLE OF NEXT WEEK...ALTHOUGH THE GFS IS MORE AMPLIFIED. THE GFS/ECMWF 925 MB TEMPS RISE TO NEAR 20C ON TUESDAY...SUPPORTING HIGH TEMPS RISING FROM MAINLY THE 60S OVER THE WEEKEND INTO THE 70S BY MONDAY OR TUESDAY...WITH LOWS PRIMARILY IN THE 50S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 125 PM CDT WED MAY 22 2013 MVFR STRATUS DECK AND LIGHT RAIN SHOWERS HAVE MOVED JUST SOUTH OF KBJI AND KFAR WITH CLEARING TO THE NORTH OF THIS LINE. EXPECT VFR CONDITIONS TO PERSIST AT ALL TAF SITES THROUGH 18 UTC THURSDAY WITH NORTHEAST WINDS GUSTING AT TIMES TO 25 KTS THIS AFTERNOON WEAKENING AFTER SUNSET. && .HYDROLOGY... ISSUED AT 125 PM CDT WED MAY 22 2013 RIVER FLOOD WARNINGS REMAIN IN EFFECT AT WALHALLA AND NECHE ALONG THE PEMBINA RIVER...WITH WALHALLA HAVING CRESTED EARLIER. BIGGEST FORECAST CHANGE IS ALONG PARK RIVER AT GRAFTON WHERE THE RECENT RAINFALL HAS TRIGGERED RAPID STAGE RISES TOWARD MAJOR AND ULTIMATELY NEAR RECORD FLOOD LEVELS. RIVER FLOOD WARNINGS ARE NOW IN EFFECT FOR MOST OF THE NORTHERN MAINSTEM RED AS WELL AS THE SOUTHERN VALLEY MINNESOTA TRIBUTARIES TO THE RED. THESE POINTS ARE ALL EXPECTED TO ACHIEVE MINOR FLOOD STAGE EXCEPT FOR OSLO WHERE MODERATE FLOODING IS FORECAST. AREAL FLOOD WARNINGS WILL BE IN EFFECT FOR PEMBINA...EASTERN CAVALIER...AND WALSH COUNTIES THROUGH THURSDAY. BY THEN AREAL FLOODING SHOULD BECOME LESS OF A CONCERN WITH LITTLE PRECIPITATION AND THE CHANCE FOR SOME DRYING WITH WARMER TEMPERATURES. A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY AFTERNOON FOR AREAS DOWNSTREAM OF THE RENWICK DAM ON THE TONGUE RIVER. WATER REMAINS VERY HIGH AT THE DAM SITE AND IS BEING HELD BACK BY A CONSTRUCTED EARTHEN LEVEE ON TOP OF THE DAM STRUCTURE. ALSO... OFFICIALS ARE CONTINUING TO MONITOR SEVERAL RETENTION DAMS TO THE WEST OF RENWICK DAM. AT THIS TIME...OFFICIALS NOTE THE TEMPORARY LEVEE ON TOP OF THE RENWICK DAM APPEARS TO BE STABLE AND WILL BE CONTINUALLY MONITORED. HOWEVER...THE THREAT REMAINS AND FAILURE WOULD MEAN MAJOR FLOODING WOULD BE IMMINENT FOR THE CITIES OF AKRA...CAVALIER...AND BATHGATE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NDZ008. MN...NONE. && $$ UPDATE...ROGERS SHORT TERM...JR LONG TERM...JR/MAKOWSKI AVIATION...ROGERS HYDROLOGY...BH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1233 PM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 1230 PM CDT WED MAY 22 2013 MAIN CHANGE TO THE FORECAST WAS TO INCREASE MAX TEMPERATURES THIS AFTERNOON A COUPLE OF DEGREES IN MOST LOCATIONS. TEMPERATURES HAVE BEEN RISING A LITTLE MORE QUICKLY THAN INITIALLY ANTICIPATED...AND THE LATEST GFS LAMP GUIDANCE SUPPORTS THE SLIGHTLY WARMER VALUES. THE REST OF THE FORECAST IS IN GOOD SHAPE AND ONLY CHANGES WERE TO CAPTURE CURRENT TRENDS. UPDATE ISSUED AT 1006 AM CDT WED MAY 22 2013 MADE ONLY MINOR ADJUSTMENTS TO THE CURRENT FORECAST. THE 22.12Z NAM AND LATEST RAP STILL SUGGEST A SMALL CHANCE FOR A SHOWER IN THE FAR SOUTHEAST CORNER OF THE FORECAST AREA TODAY. DID NOT INCREASE RAIN CHANCES IN THAT AREA FOR THE UPDATE...BUT WILL HAVE TO KEEP AN EYE ON RADAR TRENDS IN CASE A STRAY SHOWER TRIES TO MOVE IN LATER. CLOUDS CONTINUE TO CLEAR FROM NORTH TO SOUTH...WITH THE MOST ABUNDANT CLOUD COVER IN THE SOUTHERN JAMES RIVER VALLEY AS OF MID MORNING. ADJUSTED NEAR TERM SKY COVER GRIDS TO REFLECT THE TRENDS...WITH THE FORECAST FOR THIS AFTERNOON STILL ON TRACK. UPDATE ISSUED AT 641 AM CDT WED MAY 22 2013 SURFACE HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION THIS MORNING. ENOUGH GRADIENT FLOW HAS DEVELOPED TO MIX OUT MORNING FOG ACROSS THE NORTHERN PORTIONS OF THE STATE. AS OF THE 11Z OBS...THERE WAS NO FOG REPORTED ACROSS THE NORTHERN CWA. AS A RESULT...REMOVED MORNING FOG WORDING FROM THE GRIDS AND ZONES. FURTHERMORE...REGIONAL RADARS ARE NOT DETECTING ANY SHOWER ACTIVITY ACROSS THE SOUTHERN CWA. LOWERED MORNING POPS AS A RESULT. OTHERWISE...ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CDT WED MAY 22 2013 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE DRY AND COOL WEATHER IN THE WAKE OF THE STORM SYSTEM WHICH BROUGHT WIDESPREAD HEAVY RAINFALL TO MUCH OF WEST AND CENTRAL NORTH DAKOTA THE PAST SEVERAL DAYS. CURRENTLY...MOSTLY CLEAR CONDITIONS ACROSS NORTHERN NORTH DAKOTA WITH HIGH PRESSURE SLOWLY BUILDING SOUTH INTO THE NORTHERN PLAINS. SCATTERED LIGHT RAIN CONTINUES TO ADVECT WEST-SOUTHWEST FURTHER SOUTH...STILL UNDER THE INFLUENCE OF THE CLOSED UPPER LOW WHICH IS MOVING SLOWLY SOUTH AND EAST INTO THE MID/UPPER MISSISSIPPI VALLEY REGION. PRECIPITATION CHANCES WILL CONTINUE TO DIMINISH FROM NORTH TO SOUTH AS THE LOW MOVES OUT OF THE REGION...AND SKIES WILL CONTINUE TO CLEAR FROM NORTH TO SOUTH NOW THROUGH 15Z. WILL MAINTAIN MORNING FOG NORTH WITH T/TD SPREADS NEARING ZERO AS SKIES CLEAR...AND SEVERAL OBSERVING SITES REPORTING FOG. WILL MONITOR FOR POSSIBLE DENSE FOG...HOWEVER WINDS ARE EXPECTED TO INCREASE SHORTLY AFTER SUNRISE SO DO NOT EXPECT THE DURATION OF THE FOG TO BE VERY LONG. THE RIDGE CONTINUES TO BUILD SLOWLY SOUTH ACROSS THE CENTRAL DAKOTAS TODAY...WITH GENERALLY SUNNY SKIES AND HIGHS IN THE 60S. THE LATEST 00Z GFS/ECMWF DO GENERATE 100-200 J/KG OF MUCAPE THIS AFTERNOON/EARLY EVENING ALONG A COLD FRONT PUSHING SOUTH ACROSS SOUTHERN MANITOBA INTO NORTHEASTERN NORTH DAKOTA. FOR NOW WILL LEAVE THINGS DRY...BUT COULD SEE A SHOWER OR TWO AROUND THE TURTLE MOUNTAINS/DEVILS LAKE BASIN AREA. ANOTHER COOL NIGHT WEDNESDAY THANKS TO CLEAR SKIES...LIGHT WINDS...AND SFC DEWPOINTS RANGING FROM 35-45. THIS SHOULD RESULT IN LOW TEMPERATURES AROUND 40 TO 45. SOUTHEAST RETURN FLOW INCREASES LATE TONIGHT FAR WEST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 343 AM CDT WED MAY 22 2013 DRY CONDITIONS ARE EXPECTED THURSDAY AS MID/UPPER LEVEL RIDGING DEVELOPS OVER THE PLAINS. GRADIENT FLOW WILL INCREASE WEST IN RESPONSE TO AN UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST. WIND ADVISORY CONDITIONS WILL BE POSSIBLE OVER SOUTHWESTERN NORTH DAKOTA THURSDAY AFTERNOON/EVENING. THE MEDIUM RANGE MODELS PROG THE FIRST IMPULSE TO EJECT FROM OF THE AFOREMENTIONED PACIFIC NORTHWEST LOW OVER WESTERN AND CENTRAL NORTH DAKOTA FRIDAY. THIS WILL LEAD TO THUNDERSTORM CHANCES DEVELOPING AREAWIDE BY FRIDAY AFTERNOON. AN UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH THE END OF THE PERIOD. PERSISTENT SOUTHWESTERLY FLOW ALOFT COMBINED WITH GULF OF MEXICO MOISTURE TAP WILL LEAD TO CHANCES FOR THUNDERSTORMS EACH DAY THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. THE PERSISTENT RETURN FLOW SHOULD ALSO ALLOW FOR A GRADUAL WARMING TREND TO DEVELOP SATURDAY AND CONTINUE THROUGH THE END OF THE PERIOD. BY TUESDAY...HIGHS SHOULD GENERALLY BE IN THE MID 70S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1230 PM CDT WED MAY 22 2013 EAST / NORTHEAST WINDS INCREASED LATE THIS MORNING...AND EXPECT GUSTS TO NEAR 25 KTS AT ALL TERMINAL LOCATIONS THROUGH THE AFTERNOON. WINDS WILL DIMINISH THIS EVENING...BUT WILL INCREASE AGAIN THURSDAY MORNING. VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD...WITH ONLY PASSING SCATTERED CLOUDS AROUND 4KFT EXPECTED. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CK SHORT TERM...NH LONG TERM...TM AVIATION...CK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1025 AM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 1024 AM CDT WED MAY 22 2013 NO SIGNIFICANT CHANGES REQUIRED WITH THIS UPDATE AS THE INHERITED FORECAST IS ON TRACK AND BLENDED TO 15 UTC OBSERVED TRENDS. GIVEN RADAR AND SURFACE OBSERVATIONS...DID INCREASE POPS TO NEAR 100 FOR THIS MORNING ACROSS LAKES COUNTRY...DECREASING THROUGH THE AFTERNOON WITH THE CWA EXPECTED TO BE PRECIPITATION FREE BY 22-00 UTC. THE RAP HAS PERFORMED WELL IN REGARDS TO THE STRATUS SHIELD THE PAST COUPLE OF DAYS AND FOLLOWED ITS LATEST 14 UTC SOLUTION FOR CLOUD COVER. UPDATE ISSUED AT 647 AM CDT WED MAY 22 2013 NORTH TO NORTHEASTERLY WINDS PICKING UP HAVE SCOURED OUT THE FOG THAT WAS STARTING TO FORM OVER OUR NORTHWESTERN COUNTIES...SO REMOVED MENTION FOR THE REST OF THE MORNING. RAIN WILL LINGER OVER THE SOUTHEASTERN COUNTIES FOR A WHILE LONGER THIS MORNING BEFORE DRYING OUT THIS AFTERNOON. CLOUDS WILL DECREASE THROUGHOUT THE DAY. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 330 AM CDT WED MAY 22 2013 UPPER LOW FINALLY BEGINNING TO PULL AWAY FROM THE CWA AS IT WILL SLOWLY MOVE SOUTHEASTWARD INTO IA TODAY. SFC HIGH PRESSURE HAS STARTED TO NOSE DOWN OUT OF CANADA INTO THE NORTHERN PLAINS. MOST OF THE PRECIP HAS MOVED SOUTH OF THE AREA ALTHOUGH A FEW SCATTERED SHOWERS STILL LINGER IN THE SOUTHERN COUNTIES. THE NORTH HAS CLEARED OUT COMPLETELY AND THERE HAS BEEN SOME PATCHY FOG FORMATION AROUND CANDO AND LANGDON. HOWEVER...THERE IS STILL A PRESSURE GRADIENT AND THINK THIS WILL KEEP FOG FROM BECOMING WIDESPREAD AND DENSE. WILL KEEP A CLOSE EYE ON OBS THROUGH THE EARLY MORNING HOURS. SHOWERS AND CLOUDS WILL LINGER OVER THE SOUTHERN COUNTIES FOR MUCH OF THE DAY BEFORE FINALLY CLEARING OUT BY LATE AFTERNOON. THIS WILL KEEP TEMPS COOLER AND AROUND 60 WHILE THE NORTH WILL BE A BIT WARMER. THE SFC HIGH WILL MOVE FURTHER DOWN FROM CANADA INTO THE UPPER MS VALLEY TONIGHT. THIS SHOULD HELP THE NORTHER TIER ALONG WITH EASTERN COUNTIES GET DOWN TO BELOW 40 DEGREES IN SOME AREAS. THURSDAY SHOULD BE QUIET AND A BIT WARMER AS UPPER RIDGING BUILDS OVER THE REGION. WITH SOME DECENT SUNSHINE KEPT HIGHS IN THE 60S TO LOW 70S. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 330 AM CDT WED MAY 22 2013 THURSDAY NIGHT SOUTHEASTERLY WINDS STILL START PICKING UP OVER THE WESTERN COUNTIES AS SFC HIGH PRESSURE OVER MN/WI ALONG WITH A DEVELOPING LOW OVER MT CREATES A DECENT PRESSURE GRADIENT. THE WINDS WILL HELP KEEP THE WESTERN COUNTIES FROM COMPLETELY DECOUPLING AND STAY A BIT WARMER WHILE THE EAST WILL AGAIN DROP TO AROUND 40 DEGREES. SOUTHEASTERLY WINDS WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT AS A LEE TROUGH CONTINUES OVER THE WESTERN PLAINS. MODELS ARE ALL IN FAIRLY DECENT AGREEMENT ON A WEAK SHORTWAVE COMING OVER THE UPPER RIDGE AND SOME DECENT ISENTROPIC LIFT PRODUCING SOME PRECIP FRIDAY AFTERNOON INTO FRIDAY NIGHT. AT THIS POINT THE INSTABILITY SEEMS FAIRLY WEAK WITH SFC BASED CAPE STAYING WEST OF OUR AREA AND ONLY A LITTLE BIT OF ELEVATED CAPE TO WORK WITH. INCLUDED A CHANCE OF SHOWERS WITH ISOLATED THUNDERSTORMS THROUGH FRIDAY NIGHT WITH BEST CHANCES IN OUR WEST. SATURDAY-TUESDAY...00Z MODELS CONTINUE TO SUGGEST THE SYNOPTIC PATTERN WILL BE DOMINATED BY LONGWAVE TROUGHING OVER THE WESTERN US...WITH SOME DEGREE OF MID/UPPER LEVEL RIDGING INTO THE PLAINS DURING MUCH OF THIS PERIOD. A SERIES OF WEAK UPPER LEVEL SHORTWAVE TROUGHS EJECTING OUT OF THE BROADER TROUGH TO THE WEST WILL LEAD TO BOUTS OF SHOWERS OR THUNDERSTORMS ACROSS THE REGION WITHIN THE LOW TO MID-LEVEL WARM AIR ADVECTION ZONE ASSOCIATED WITH THE INDIVIDUAL WAVES. WITH THIS TYPE OF PATTERN...CONFIDENCE IN THE TIMING/PLACEMENT OF INDIVIDUAL WAVES IS LOW...SO CONTINUED TO CARRY SOME POPS FOR MUCH OF THE PERIOD...ALTHOUGH MANY DRY HOURS ARE EXPECTED. THE 00Z GFS/ECMWF SUGGEST A TREND TO A MORE PREDOMINANT ACTIVE SOUTHWEST FLOW PATTERN ACROSS THE PLAINS TOWARDS THE MIDDLE OF NEXT WEEK...ALTHOUGH THE GFS IS MORE AMPLIFIED. THE GFS/ECMWF 925 MB TEMPS RISE TO NEAR 20C ON TUESDAY...SUPPORTING HIGH TEMPS RISING FROM MAINLY THE 60S OVER THE WEEKEND INTO THE 70S BY MONDAY OR TUESDAY...WITH LOWS PRIMARILY IN THE 50S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 1024 AM CDT WED MAY 22 2013 THE EDGE OF THE MVFR STRATUS FIELD WITH EMBEDDED LIGHT RAIN WAS JUST OVER THE KBJI AND KFAR TERMINALS...WITH VFR CONDITIONS EXPECTED BY 16-17 UTC. OTHERWISE VFR CONDITIONS ARE EXPECTED FOR KDVL...KGFK AND KTVF FOR THE 12 UTC TAFS. WILL CONTINUE TO MONITOR STRATUS ACROSS WESTERN ONTARIO AND EASTERN MANITOBA PUSHING SOUTHEAST. HOWEVER....THE STRATUS IS EXPECTED TO DISSOLVE THROUGH THE DAY BEFORE REACHING NORTH DAKOTA. NORTHEAST WIND GUSTS OF 20-25 KTS WILL BE COMMON AT ALL TAF SITES LATE THIS MORNING AND AFTERNOON. && .HYDROLOGY... ISSUED AT 650 PM CDT TUE MAY 21 2013 RAIN SHOWERS WILL BE ON THE WANE FROM THIS EVENING THROUGH WEDNESDAY ALLOWING RIVER FORECASTING TO BE MORE RUNOFF AS OPPOSED TO QPF BASED. RIVER FLOOD WARNINGS REMAIN IN EFFECT AT WALHALLA AND NECHE ALONG THE PEMBINA RIVER WITH WALHALLA HAVING CRESTED EARLIER. BIGGEST FORECAST CHANGE IS ALONG PARK RIVER AT GRAFTON WHERE THE COPIOUS RAINFALL HAS TRIGGERED RAPID STAGE RISES TOWARD MAJOR AND ULTIMATELY NEAR RECORD FLOOD LEVELS. RIVER FLOOD WARNINGS ARE NOW IN EFFECT FOR MOST OF THE MAINSTEM RED AS WELL AS THE SOUTHERN VALLEY MINNESOTA TRIBUTARIES TO THE RED. THESE POINTS ARE ALL EXPECTED TO ACHIEVE MINOR FLOOD STAGE SAVE FOR OSLO WHERE MODERATE FLOODING IS FORECAST. AREAL FLOOD WARNINGS WILL BE IN EFFECT FOR PEMBINA...EASTERN CAVALIER...AND WALSH COUNTIES THROUGH THURSDAY. BY THEN AREAL FLOODING SHOULD BECOME LESS OF A CONCERN WITH A DEARTH OF PRECIPITATION AND THE CHANCE FOR SOME DRYING WITH WARMER TEMPERATURES. THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR PARTS OF PEMBINA COUNTY AS HEAVY RAINFALL OVER THE PAST FEW DAYS HAS CAUSED FLOOD WATERS TO APPROACH THE TOP OF THE SPILLWAY AT THE RENWICK DAM. WATER REMAINS VERY HIGH AND IS BEING HELD BACK BY A CONSTRUCTED EARTHEN LEVEE ON TOP OF THE DAM STRUCTURE. OFFICIALS CONTINUE TO MONITOR THE DAM AND THE NEW CLAY LEVEE FOR ANY EROSION. THERE ARE SEVERAL OLD RETENTION DAMS TO THE WEST OF THE RENWICK DAM...AND WITH THE LARGE AMOUNT OF WATER IN THE AREA THESE DAMS COULD FAIL. IF ONE OF THESE OLDER DAMS TO THE WEST DID FAIL...THE TEMPORARY LEVEE ON TOP OF THE RENWICK DAM WOULD NO LONGER BE ABLE TO HOLD BACK WATER...AND FLOODING WOULD BE IMMINENT FOR THE CITIES OF AKRA...CAVALIER...AND BATHGATE. THE PEMBINA COUNTY EMERGENCY MANAGEMENT ANTICIPATES A POSSIBLE BREACH WITHIN THE NEXT 12 HOURS...AND HAVE ORDERED A MANDATORY EVACUATION FOR THE AREA IMMEDIATELY DOWNSTREAM OF THE RENWICK DAM...INCLUDING THE CITY OF CAVALIER. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...AYD SHORT TERM...JR LONG TERM...JR/MAKOWSKI AVIATION...AYD HYDROLOGY...WJB/TG/JH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1012 AM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 1006 AM CDT WED MAY 22 2013 MADE ONLY MINOR ADJUSTMENTS TO THE CURRENT FORECAST. THE 22.12Z NAM AND LATEST RAP STILL SUGGEST A SMALL CHANCE FOR A SHOWER IN THE FAR SOUTHEAST CORNER OF THE FORECAST AREA TODAY. DID NOT INCREASE RAIN CHANCES IN THAT AREA FOR THE UPDATE...BUT WILL HAVE TO KEEP AN EYE ON RADAR TRENDS IN CASE A STRAY SHOWER TRIES TO MOVE IN LATER. CLOUDS CONTINUE TO CLEAR FROM NORTH TO SOUTH...WITH THE MOST ABUNDANT CLOUD COVER IN THE SOUTHERN JAMES RIVER VALLEY AS OF MID MORNING. ADJUSTED NEAR TERM SKY COVER GRIDS TO REFLECT THE TRENDS...WITH THE FORECAST FOR THIS AFTERNOON STILL ON TRACK. UPDATE ISSUED AT 641 AM CDT WED MAY 22 2013 SURFACE HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION THIS MORNING. ENOUGH GRADIENT FLOW HAS DEVELOPED TO MIX OUT MORNING FOG ACROSS THE NORTHERN PORTIONS OF THE STATE. AS OF THE 11Z OBS...THERE WAS NO FOG REPORTED ACROSS THE NORTHERN CWA. AS A RESULT...REMOVED MORNING FOG WORDING FROM THE GRIDS AND ZONES. FURTHERMORE...REGIONAL RADARS ARE NOT DETECTING ANY SHOWER ACTIVITY ACROSS THE SOUTHERN CWA. LOWERED MORNING POPS AS A RESULT. OTHERWISE...ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CDT WED MAY 22 2013 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE DRY AND COOL WEATHER IN THE WAKE OF THE STORM SYSTEM WHICH BROUGHT WIDESPREAD HEAVY RAINFALL TO MUCH OF WEST AND CENTRAL NORTH DAKOTA THE PAST SEVERAL DAYS. CURRENTLY...MOSTLY CLEAR CONDITIONS ACROSS NORTHERN NORTH DAKOTA WITH HIGH PRESSURE SLOWLY BUILDING SOUTH INTO THE NORTHERN PLAINS. SCATTERED LIGHT RAIN CONTINUES TO ADVECT WEST-SOUTHWEST FURTHER SOUTH...STILL UNDER THE INFLUENCE OF THE CLOSED UPPER LOW WHICH IS MOVING SLOWLY SOUTH AND EAST INTO THE MID/UPPER MISSISSIPPI VALLEY REGION. PRECIPITATION CHANCES WILL CONTINUE TO DIMINISH FROM NORTH TO SOUTH AS THE LOW MOVES OUT OF THE REGION...AND SKIES WILL CONTINUE TO CLEAR FROM NORTH TO SOUTH NOW THROUGH 15Z. WILL MAINTAIN MORNING FOG NORTH WITH T/TD SPREADS NEARING ZERO AS SKIES CLEAR...AND SEVERAL OBSERVING SITES REPORTING FOG. WILL MONITOR FOR POSSIBLE DENSE FOG...HOWEVER WINDS ARE EXPECTED TO INCREASE SHORTLY AFTER SUNRISE SO DO NOT EXPECT THE DURATION OF THE FOG TO BE VERY LONG. THE RIDGE CONTINUES TO BUILD SLOWLY SOUTH ACROSS THE CENTRAL DAKOTAS TODAY...WITH GENERALLY SUNNY SKIES AND HIGHS IN THE 60S. THE LATEST 00Z GFS/ECMWF DO GENERATE 100-200 J/KG OF MUCAPE THIS AFTERNOON/EARLY EVENING ALONG A COLD FRONT PUSHING SOUTH ACROSS SOUTHERN MANITOBA INTO NORTHEASTERN NORTH DAKOTA. FOR NOW WILL LEAVE THINGS DRY...BUT COULD SEE A SHOWER OR TWO AROUND THE TURTLE MOUNTAINS/DEVILS LAKE BASIN AREA. ANOTHER COOL NIGHT WEDNESDAY THANKS TO CLEAR SKIES...LIGHT WINDS...AND SFC DEWPOINTS RANGING FROM 35-45. THIS SHOULD RESULT IN LOW TEMPERATURES AROUND 40 TO 45. SOUTHEAST RETURN FLOW INCREASES LATE TONIGHT FAR WEST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 343 AM CDT WED MAY 22 2013 DRY CONDITIONS ARE EXPECTED THURSDAY AS MID/UPPER LEVEL RIDGING DEVELOPS OVER THE PLAINS. GRADIENT FLOW WILL INCREASE WEST IN RESPONSE TO AN UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST. WIND ADVISORY CONDITIONS WILL BE POSSIBLE OVER SOUTHWESTERN NORTH DAKOTA THURSDAY AFTERNOON/EVENING. THE MEDIUM RANGE MODELS PROG THE FIRST IMPULSE TO EJECT FROM OF THE AFOREMENTIONED PACIFIC NORTHWEST LOW OVER WESTERN AND CENTRAL NORTH DAKOTA FRIDAY. THIS WILL LEAD TO THUNDERSTORM CHANCES DEVELOPING AREAWIDE BY FRIDAY AFTERNOON. AN UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH THE END OF THE PERIOD. PERSISTENT SOUTHWESTERLY FLOW ALOFT COMBINED WITH GULF OF MEXICO MOISTURE TAP WILL LEAD TO CHANCES FOR THUNDERSTORMS EACH DAY THIS WEEKEND THROUGH THE FIRST PART OF NEXT WEEK. THE PERSISTENT RETURN FLOW SHOULD ALSO ALLOW FOR A GRADUAL WARMING TREND TO DEVELOP SATURDAY AND CONTINUE THROUGH THE END OF THE PERIOD. BY TUESDAY...HIGHS SHOULD GENERALLY BE IN THE MID 70S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 641 AM CDT WED MAY 22 2013 VFR CIGS ALL TERMINALS THROUGH THE 12Z TAF PERIOD. EARLY MORNING FOG POSSIBLE AT KMOT-KISN THROUGH 14Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CK SHORT TERM...NH LONG TERM...TM AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
112 AM CDT WED MAY 22 2013 .UPDATE... ISSUED AT 112 AM CDT WED MAY 22 2013 ONLY MINIMAL CHANGES WERE NEEDED FOR THIS EARLY MORNING FORECAST UPDATE. CLOUDS CONTINUE TO CLEAR ACROSS THE NORTH WITH HIGH PRESSURE SLOWLY BUILDING SOUTH INTO THE NORTHERN PLAINS. ISOLATED TO SCATTERED LIGHT RAIN WILL PERSIST CENTRAL AND SOUTH...WITH CHANCES FOR PRECIPITATION DIMINISHING FROM NORTH TO SOUTH NOW THROUGH 15Z...AS THE UPPER LOW CONTINUES TO MOVE SOUTH AND EAST TOWARDS THE MISSISSIPPI VALLEY. WILL MAINTAIN FOG IN THE FORECAST NORTH WITH T/TD SPREADS NEARING ZERO AT SOME LOCATIONS WHERE SKIES HAVE CLEARED. UPDATE ISSUED AT 853 PM CDT TUE MAY 21 2013 ISENTROPIC LIFT PERSISTS ACROSS THE SOUTH AND WEST...WITH THE WEST LIKELY GETTING SOME UPSLOPE COMPONENT AS WELL AS EASTERLY LOW LEVEL WINDS CONTINUE TO PULL LOW LEVEL MOISTURE INTO THE REGION. UPPED THE CHANCE OF RAIN SHOWERS TO LIKELY ACROSS PORTIONS OF THE SOUTH FOR THE EVENING AND EARLY MORNING. SO FAR DO NOT SEE A FIRM TREND ON CLEARING ACROSS THE NORTH YET. SO HAVE SLOWED THE PROGRESSION OF CLEARING UNTIL LATER TONIGHT. THIS MAY CAUSE SOME PROBLEMS WITH FOG FORMATION NORTH UNTIL LATE. UPSLOPE FLOW CONTRIBUTING TO LIGHT FOG SOUTHWEST THIS EVENING. UPDATE ISSUED AT 650 PM CDT TUE MAY 21 2013 AT 6 PM CDT...THE CLOUD SHIELD EXTENDS ACROSS ALL OF NORTH DAKOTA EXCEPT THE FAR NORTHERN TIER OF COUNTIES WHERE BREAKS IN THE OVERCAST ARE NOW FORMING. AFTER SUNSET THE EAST NORTHEAST FLOW OUT OF CANADA WITH WARMER TEMPERATURES AND LOWER DEW POINTS WILL FURTHER ERODE THE CLOUDS. WITH MINOT STILL REPORTED A LIGHT SHOWER ADDED SPRINKLES FOR SEVERAL HOURS THIS EVENING ALONG AND NORTH OF LAKE SAKAKAWEA EXCLUDING THE NORTHERN BORDER COUNTIES WHERE CLEARING WILL DEFINITELY BE FOUND. ACROSS THE SOUTH HALF WILL STILL SEE SCATTERED SHOWERS THIS EVENING FOLLOWED BY CLEARING OVERNIGHT. WILL THE NORTH CLEARING BY MIDNIGHT...AND ABUNDANT SURFACE MOISTURE PRESENT...AREAS OF FOG STILL LOOK REASONABLE. TEMPERATURE TRENDS LOOK GOOD AND DID NOT TOUCH THEM WITH THIS FORECAST. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 327 PM CDT TUE MAY 21 2013 THE HIGHLIGHT OF THE SHORT TERM IS THE END OF THE LONG DURATION RAINFALL EVENT ACROSS THE AREA. FOR TONIGHT...THE RAP THROUGHOUT THE DAY HAS HAD A GOOD HANDLE ON THE STRATUS DECK ACROSS THE AREA..AND FOLLOWED ITS LATEST 19 UTC RUN FOR CLOUD COVER THROUGH THE NIGHT WHICH ADVECTS DRIER AIR SOUTHWEST AND SCOURS OUT THE STRATUS. DID ADD A MENTION OF FOG TO THE NORTHWEST AND NORTH CENTRAL WHERE SKIES FIRST CLEAR TONIGHT AND WINDS BECOME LIGHT...ALLOWING FOR GOOD RADIATIONAL COOLING INTO THE UPPER 30S AND SATURATION IN LIGHT OF THE RECENT RAINFALL. A QUIET WEDNESDAY IS FORECAST WITH A SURFACE RIDGE AXIS ACROSS THE AREA. GIVEN GOOD MODEL AGREEMENT...USED A BLEND OF THE 12 UTC GEM/GFS/NAM/ECMWF AND 15 UTC SREF FOR ALL FIELDS...WITH GENERALLY SUNNY SKIES AND HIGHS IN THE 60S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 327 PM CDT TUE MAY 21 2013 BY WEDNESDAY NIGHT AN UPPER LEVEL SHORTWAVE RIDGE BETWEEN THE EXITING LOW PRESSURE SYSTEM TO THE EAST...AND THE ESTABLISHED UPPER LEVEL LOW OVER THE WEST COAST/ROCKIES...WILL BE SITUATED OVER THE PLAINS OF NORTH AMERICA. AT THE SURFACE...COOL HIGH PRESSURE RIDGE MOVING SOUTH FROM CANADA NOSES INTO THE DAKOTAS. BY THURSDAY THE SURFACE PRESSURE GRADIENT INCREASES AS THE INTENSIFYING SURFACE LOW OVER THE ROCKIES/LEE OF THE ROCKIES SETS UP A STRONGER SOUTHERLY/SOUTHEASTERLY WIND FLOW ACROSS THE WESTERN PLAINS. SOUTHEAST WINDS 20 TO 30 MPH CAN BE EXPECTED OVER THE WESTERN THIRD OF NORTH DAKOTA. FRIDAY THROUGH THE MEMORIAL DAY WEEKEND...THE LARGE UPPER LEVEL LOW OVER THE ROCKIES SETS UP A SOUTHWEST FLOW ALOFT OVER NORTH DAKOTA...AND A SERIES OF UPPER LEVEL IMPULSES WILL TRAVERSE NORTHEASTWARD ACROSS THE DAKOTAS. THUS A CHANCE OF THUNDERSTORMS THROUGHOUT THIS PERIOD. FAIRLY SEASONABLE TEMPERATURES IN THE LONG TERM...WITH HIGHS IN THE 60S AND 70S AND LOWS IN THE 40S AND 50S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 112 AM CDT WED MAY 22 2013 BOUNDARY LAYER MOISTURE CONTINUES TO DECREASE...WITH MAINLY VFR CIGS NOW AT KDIK-KBIS-KJMS...CLEAR SKIES AT KMOT...AND TRENDING TOWARDS SKC AT KISN. MAY STILL SEE SOME MVFR CIGS AT THE SOUTHERN TERMINALS OF KDIK-KBIS-KJMS EARLY THIS MORNING. ALL TERMINALS WILL BE SKC BY 15-18Z TODAY AND REMAIN SO THROUGH THE REMAINDER OF THE 06Z TAF PERIOD. && .HYDROLOGY... ISSUED AT 327 PM CDT TUE MAY 21 2013 FLOOD WARNINGS CONTINUE FOR THE PIPESTEM CREEK NEAR PINGREE AND THE FORECAST POINTS OF TOWNER...BANTRY AND WESTHOPE ON THE SOURIS. CONTINUING TO MONITOR THE WINTERING RIVER NEAR KARLSRUHE AND THE WILLOW CREEK NEAR WILLOW CITY WHICH MAY APPROACH FLOOD STAGE IN THE NEXT 24-48 HOURS. HAVE HELD OFF ON A FLOOD WARNING FOR NOW...AND WILL WATCH HOW THESE WATERWAYS RESPOND TO RUNOFF. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...AYD LONG TERM...JV AVIATION...NH HYDROLOGY...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
640 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES TODAY...WITH A COLD FRONT MOVING INTO THE OHIO VALLEY TONIGHT. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THIS FRONT. A SECONDARY TROUGH WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY. MUCH COLDER AIR WILL MOVE INTO THE REGION ON FRIDAY...AS HIGH PRESSURE BUILDS INTO THE OHIO VALLEY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SOMEWHAT-DISORGANIZED SURFACE LOW IS CURRENTLY LOCATED IN IOWA AND NORTHERN ILLINOIS. THIS LOW WILL SLOWLY MOVE TO THE EAST TODAY...STRENGTHENING SLIGHTLY AS IT CROSSES THE SOUTHERN GREAT LAKES. SOUTH OF THE LOW...A WEAK COLD FRONT WILL MOVE INTO THE ILN CWA BY EVENING. THIS FRONT IS TOUGH TO PICK OUT ON SURFACE TEMPERATURE FIELDS...BUT IS A BIT MORE EVIDENT WHEN EXAMINING THETA-E SLIGHTLY ALOFT...AND ALSO LOOKING FOR SLIGHT WIND SHIFT FROM SSW TO WSW. AT THE SAME TIME...A CLOSED UPPER LOW OVER THE NORTHERN MISSISSIPPI VALLEY WILL BEGIN ITS MOVE TO THE EAST...WITH A SHORTWAVE ROTATING NORTHEAST THROUGH INDIANA AND MICHIGAN. IN THE RIGHT ENTRANCE REGION OF AN UPPER JET...THE SETUP OVER OHIO WILL BE FAVORABLE FOR LARGE-SCALE LIFT. THE STANDARD SUITE OF MODELS (GFS/NAM/CMC/ECMWF) HAS THUS FAR APPEARED MUCH TOO AGGRESSIVE WITH THE OVERNIGHT PRECIPITATION FORECAST OVER ILLINOIS AND INDIANA. THIS IS ADMITTEDLY A REGION WHERE LIFT IS FORECAST TO CONTINUE TO ENHANCE THROUGH MORNING...IN A REGION OF FALLING HEIGHTS AND A 30-40 KNOT LLJ. DEWPOINTS NORTH OF THE CURRENT TENNESSEE CONVECTION ARE ABOUT 3-6 DEGREES LOWER THAN IN THE SOUTHERN STATES...BUT THE AIR MASS COULD NOT BE DESCRIBED AS PARTICULARLY DRY. AS WAS THE CASE YESTERDAY...THE HRRR HAS THE CLOSEST APPROXIMATION TO THE CURRENT ACTIVITY. SEVERAL OTHER CONVECTIVE-ALLOWING MODELS DEPICT QUITE A BIT OF CONVECTION MOVING INTO THE ILN CWA AS EARLY AS 12Z...WHICH DOES NOT APPEAR REALISTIC GIVEN THE LACK OF INSTABILITY AND CURRENT RADAR TRENDS. THE OVERALL CHANCES FOR RAIN IN THE ILN CWA DO NOT APPEAR PARTICULARLY HIGH THROUGH THE MORNING HOURS...THOUGH SLIGHTLY MORE SO IN THE WESTERN PART OF THE CWA. THE MAIN CONCERN FOR THE FORECAST TODAY IS THE POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON. GIVEN THE WIDE VARIANCE IN THE HANDLING OF THE CURRENT WEATHER SITUATION...AND THE FACT THAT THESE MESOSCALE FEATURES WILL BE VERY IMPORTANT IN CONVECTIVE FORECASTING FOR THIS AFTERNOON...IT IS TOUGH TO TRUST ANY OF THE SPECIFIC QPF/SIM-RADAR DEPICTIONS FOR THE AFTERNOON HOURS. TO BEGIN WITH THE BIGGEST LIMITING FACTOR FOR TODAY...INSTABILITY WILL BE IN QUESTION. GIVEN THE EXPECTED CLOUD COVER...AND EVEN PRECIPITATION IN SOME PLACES...THE SURFACE TEMP FORECAST IS ON THE LOW SIDE OF GUIDANCE. GIVEN THE THERMAL PROFILE...MLCAPE WILL STRUGGLE TO REACH 1000 J/KG...WITH THE MOST INSTABILITY FORECAST TO BE IN THE SOUTHEASTERN PARTS OF THE CWA. IN THE NORTHWEST...WHERE TEMPS WILL BE THE COOLEST...INSTABILITY WILL BE EVEN LESS (500 J/KG OR SO). SOUNDINGS ARE RELATIVELY MOIST THROUGH THEIR DEPTH...WITH RATHER LOW LCL HEIGHTS (AROUND 2000-3000 FEET AGL) FORECAST ON THE GFS/NAM (THE RAP13 APPEARS A BIT DRIER). BECAUSE OF THE MOIST CONDITIONS...THE CAPE PROFILE IS NARROW. UNLIKE YESTERDAY...THE OVERALL FORCING ENVIRONMENT WILL BE MORE FAVORABLE FOR CONVECTIVE DEVELOPMENT...EVEN IF INSTABILITY IS WEAK. WIND SHEAR IS ALSO SOMEWHAT OF A STRENGTH FOR TODAY...ALTHOUGH MODEL-TO-MODEL ASSESSMENT ON SHEAR VALUES IS NOT IN AS GOOD OF CONSENSUS AS IS USUALLY THE CASE. MOST OF THE SHEAR WILL BE FAIRLY UNIDIRECTIONAL (ALL IN THE TOP-RIGHT QUADRANT OF THE HODOGRAPH)...BUT WITH A DECENT CHANGE IN SPEED. 30-40 KNOTS OF DEEP LAYER SHEAR WILL BE PRESENT...WITH 15-25 KNOTS IN THE 0-1KM LAYER. 0-3KM SRH VALUES WILL GET INTO THE 100-200 RANGE...SO THERE WILL CERTAINLY BE SOME POTENTIAL FOR ROTATING STORMS. THIS COULD BE ENHANCED BY BOUNDARY INTERACTIONS OR AREAS OF BACKING SURFACE WINDS (PERHAPS FURTHER NORTH AND CLOSER TO THE SURFACE LOW). THE LACK OF INSTABILITY...ESPECIALLY IN THE HAIL GROWTH ZONE...WILL LIMIT THE POTENTIAL FOR LARGE HAIL (PERHAPS OUTSIDE OF A STRONGER / ROTATING UPDRAFT). THE THREAT FOR STRONG WINDS AND TORNADOES DOES APPEAR TO EXIST...BUT THE THERMODYNAMIC ENVIRONMENT SEEMS TO LIMIT THIS FROM BEING A HIGHER-END SEVERE EVENT. A CLOUDIER/GRUNGIER MORNING WOULD SUPPORT AN ISOLATED SEVERE THREAT WITH CLUSTERS OF STORMS CAPABLE OF STRONG WINDS AND MAYBE A BIT OF ROTATION. THE OUTSIDE SHOT FOR TODAY WOULD BE A GREATER DEAL OF BOUNDARY LAYER DESTABILIZATION (BETWEEN INSOLATION AND MOISTURE ADVECTION)...WHICH WOULD BRING A GREATER RISK OF ALL THE SEVERE MODES COMING TO THE TABLE. HOWEVER...GIVEN ALL THE EVIDENCE...THIS FORECAST WILL LEAN TOWARD THE FORMER SOLUTION. THE HWO WILL FOLLOW SUIT WITH A RELATIVELY TYPICAL-SOUNDING SEVERE THREAT WORDING. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... THE INITIAL COLD FRONT WILL BE CROSSING THE ILN CWA DURING THE EVENING HOURS...PRODUCING A RELATIVELY SMALL CHANGE IN THE TEMPERATURE AND WIND FIELDS. BEHIND THE FRONT...PRECIPITATION WILL BECOME LESS LIKELY...ESPECIALLY IN THE SOUTH AND SOUTHWEST PORTIONS OF THE CWA. A SECONDARY TROUGH (BOTH ALOFT AND AT THE SURFACE) WILL BE ROTATING SOUTHEAST THROUGH THE CWA ON THURSDAY. THIS WILL BRING A RENEWED CHANCE OF PRECIPITATION...ESPECIALLY IN THE NORTHERN AND EASTERN PARTS OF THE CWA. INSTABILITY WILL BE VERY WEAK...BUT JUST ENOUGH FOR SOME RISK OF THUNDER. THE AIR MASS ALOFT WILL BE INCREASINGLY COLD...HELPING TO LEAD TO THE POSSIBILITY OF CONVECTIVE SHOWERS. ALONG WITH THIS ACTIVITY WILL BE A SECONDARY COLD FRONT...MUCH BETTER DEFINED THAN THE FIRST. A NNW WIND SHIFT WILL ALLOW FOR COLD ADVECTION TO BEGIN ON THURSDAY (AND ESPECIALLY THURSDAY NIGHT). AS A RESULT...THE MAX TEMP GRADIENT FOR THURSDAY IS SOMEWHAT SHARP (ABOUT 10 DEGREES FROM SW TO NE) AND THURSDAY NIGHT MIN TEMPS MAY GET INTO THE 30S IN THE NORTHERN PORTIONS OF THE CWA. WITH DRY HIGH PRESSURE IN PLACE FOR FRIDAY...RELATIVELY TRANQUIL CONDITIONS ARE EXPECTED. && .LONG TERM /SATURDAY THROUGH TUESDAY/... DRY WEATHER SHOULD CONTINUE ON SATURDAY FOR MOST OF THE AREA EXCEPT FOR FAR SOUTHEAST COUNTIES WHERE A DEVELOPING FRONTAL BOUNDARY MAY CAUSE A FEW SHOWERS. FOR SUNDAY THROUGH TUESDAY...THAT FRONTAL BOUNDARY IS FORECAST TO LINGER ACROSS KENTUCKY. THIS PATTERN WILL PROVIDE A CHANCE OF SHOWERS EACH DAY TO THE SOUTHERN PART OF THE FORECAST AREA...WITH NORTHERN LOCATIONS ENJOYING A PERIOD OF DRY WEATHER. SLIGHTLY BELOW NORMAL HIGHS AVERAGING IN THE LOWER 70S ON THURSDAY WILL BE FOLLOWED BY BELOW NORMAL 60S ON FRIDAY UNDER CLOUDS AND SHOWERS. TEMPERATURES WILL THEN GRADUALLY REBOUND FROM SATURDAY ONWARD...WITH HIGHS REACHING THE MID AND UPPER 70S BY TUESDAY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... REGION WILL REMAIN IN A MOIST SOUTH TO SOUTHWEST FLOW AT THE SURFACE AND ALOFT AS THE CENTER OF AN UPPER LEVEL LOW PIVOTS SOUTHEAST TOWARD THE WESTERN GREAT LAKES. AS THE LOW MOVES SOUTHEAST...A SURFACE COLD FRONT WILL PUSH EAST THROUGH OUR AREA TONIGHT. LATEST ANALYSIS AND MODELS INDICATE THAT OUR AREA IS STILL IN AN INSTABILITY MINIMUM THIS MORNING. AS SUCH...THE LOW LEVEL JET THAT IS OVER THE AREA MAY PRODUCE SOME SCATTERED SHOWERS THIS MORNING. FOR THIS AFTERNOON INTO THIS EVENING...THE PROSPECTS OF SHOWERS AND THUNDERSTORMS WILL INCREASE AS DAYTIME HEATING INTERACTS WITH LARGE SCALE SYNOPTIC LIFT. BEST CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE FROM MID AFTERNOON INTO THE EVENING HOURS. HAVE PLACED THIS IN THE TAFS WITH A PREDOMINANT MVFR -SHRA AND A VCTS/CB. AS STORMS BECOME MORE APPARENT AND CAN BE TRACKED ON RADAR...TAFS WILL BE FINED TUNED ACCORDINGLY. WITH A MOIST AIRMASS...SOME LOCAL MVFR CIGS AND IFR VSBYS WILL BE POSSIBLE IN THUNDERSTORMS. DAYTIME HEATING/MIXING WILL PRODUCE SOUTH/SOUTHWEST WINDS OF 12-16 KNOTS WITH GUSTS UP TO 30 KNOTS. FOR TONIGHT...THE COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE REGION. LARGE SCALE LIFT DECREASES AS DOES THE INSTABILITY. HOWEVER...MODELS INDICATE THAT THERE COULD BE A BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ALONG AND AHEAD OF THE FRONT. HAVE INDICATED THIS WITH A VCSH AS THUNDERSTORMS CHANCES WILL WANE BETWEEN 01Z AND 06Z. AFTER FRONTAL PASSAGE...THERE SHOULD BE A REPRIEVE IN PCPN BUT LOW LEVEL MOISTURE WILL REMAIN. IT IS UNCLEAR AT THIS TIME IF MVFR CEILINGS WILL DEVELOP BEHIND THE FRONT SO HAVE LEFT THEM AT VFR FOR NOW. OUTLOOK...MVFR CONDITIONS POSSIBLE WITH SHOWERS AND EMBEDDED THUNDERSTORMS THURSDAY INTO THURSDAY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
430 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES TODAY...WITH A COLD FRONT MOVING INTO THE OHIO VALLEY TONIGHT. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THIS FRONT. A SECONDARY TROUGH WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY. MUCH COLDER AIR WILL MOVE INTO THE REGION ON FRIDAY...AS HIGH PRESSURE BUILDS INTO THE OHIO VALLEY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SOMEWHAT-DISORGANIZED SURFACE LOW IS CURRENTLY LOCATED IN IOWA AND NORTHERN ILLINOIS. THIS LOW WILL SLOWLY MOVE TO THE EAST TODAY...STRENGTHENING SLIGHTLY AS IT CROSSES THE SOUTHERN GREAT LAKES. SOUTH OF THE LOW...A WEAK COLD FRONT WILL MOVE INTO THE ILN CWA BY EVENING. THIS FRONT IS TOUGH TO PICK OUT ON SURFACE TEMPERATURE FIELDS...BUT IS A BIT MORE EVIDENT WHEN EXAMINING THETA-E SLIGHTLY ALOFT...AND ALSO LOOKING FOR SLIGHT WIND SHIFT FROM SSW TO WSW. AT THE SAME TIME...A CLOSED UPPER LOW OVER THE NORTHERN MISSISSIPPI VALLEY WILL BEGIN ITS MOVE TO THE EAST...WITH A SHORTWAVE ROTATING NORTHEAST THROUGH INDIANA AND MICHIGAN. IN THE RIGHT ENTRANCE REGION OF AN UPPER JET...THE SETUP OVER OHIO WILL BE FAVORABLE FOR LARGE-SCALE LIFT. THE STANDARD SUITE OF MODELS (GFS/NAM/CMC/ECMWF) HAS THUS FAR APPEARED MUCH TOO AGGRESSIVE WITH THE OVERNIGHT PRECIPITATION FORECAST OVER ILLINOIS AND INDIANA. THIS IS ADMITTEDLY A REGION WHERE LIFT IS FORECAST TO CONTINUE TO ENHANCE THROUGH MORNING...IN A REGION OF FALLING HEIGHTS AND A 30-40 KNOT LLJ. DEWPOINTS NORTH OF THE CURRENT TENNESSEE CONVECTION ARE ABOUT 3-6 DEGREES LOWER THAN IN THE SOUTHERN STATES...BUT THE AIR MASS COULD NOT BE DESCRIBED AS PARTICULARLY DRY. AS WAS THE CASE YESTERDAY...THE HRRR HAS THE CLOSEST APPROXIMATION TO THE CURRENT ACTIVITY. SEVERAL OTHER CONVECTIVE-ALLOWING MODELS DEPICT QUITE A BIT OF CONVECTION MOVING INTO THE ILN CWA AS EARLY AS 12Z...WHICH DOES NOT APPEAR REALISTIC GIVEN THE LACK OF INSTABILITY AND CURRENT RADAR TRENDS. THE OVERALL CHANCES FOR RAIN IN THE ILN CWA DO NOT APPEAR PARTICULARLY HIGH THROUGH THE MORNING HOURS...THOUGH SLIGHTLY MORE SO IN THE WESTERN PART OF THE CWA. THE MAIN CONCERN FOR THE FORECAST TODAY IS THE POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON. GIVEN THE WIDE VARIANCE IN THE HANDLING OF THE CURRENT WEATHER SITUATION...AND THE FACT THAT THESE MESOSCALE FEATURES WILL BE VERY IMPORTANT IN CONVECTIVE FORECASTING FOR THIS AFTERNOON...IT IS TOUGH TO TRUST ANY OF THE SPECIFIC QPF/SIM-RADAR DEPICTIONS FOR THE AFTERNOON HOURS. TO BEGIN WITH THE BIGGEST LIMITING FACTOR FOR TODAY...INSTABILITY WILL BE IN QUESTION. GIVEN THE EXPECTED CLOUD COVER...AND EVEN PRECIPITATION IN SOME PLACES...THE SURFACE TEMP FORECAST IS ON THE LOW SIDE OF GUIDANCE. GIVEN THE THERMAL PROFILE...MLCAPE WILL STRUGGLE TO REACH 1000 J/KG...WITH THE MOST INSTABILITY FORECAST TO BE IN THE SOUTHEASTERN PARTS OF THE CWA. IN THE NORTHWEST...WHERE TEMPS WILL BE THE COOLEST...INSTABILITY WILL BE EVEN LESS (500 J/KG OR SO). SOUNDINGS ARE RELATIVELY MOIST THROUGH THEIR DEPTH...WITH RATHER LOW LCL HEIGHTS (AROUND 2000-3000 FEET AGL) FORECAST ON THE GFS/NAM (THE RAP13 APPEARS A BIT DRIER). BECAUSE OF THE MOIST CONDITIONS...THE CAPE PROFILE IS NARROW. UNLIKE YESTERDAY...THE OVERALL FORCING ENVIRONMENT WILL BE MORE FAVORABLE FOR CONVECTIVE DEVELOPMENT...EVEN IF INSTABILITY IS WEAK. WIND SHEAR IS ALSO SOMEWHAT OF A STRENGTH FOR TODAY...ALTHOUGH MODEL-TO-MODEL ASSESSMENT ON SHEAR VALUES IS NOT IN AS GOOD OF CONSENSUS AS IS USUALLY THE CASE. MOST OF THE SHEAR WILL BE FAIRLY UNIDIRECTIONAL (ALL IN THE TOP-RIGHT QUADRANT OF THE HODOGRAPH)...BUT WITH A DECENT CHANGE IN SPEED. 30-40 KNOTS OF DEEP LAYER SHEAR WILL BE PRESENT...WITH 15-25 KNOTS IN THE 0-1KM LAYER. 0-3KM SRH VALUES WILL GET INTO THE 100-200 RANGE...SO THERE WILL CERTAINLY BE SOME POTENTIAL FOR ROTATING STORMS. THIS COULD BE ENHANCED BY BOUNDARY INTERACTIONS OR AREAS OF BACKING SURFACE WINDS (PERHAPS FURTHER NORTH AND CLOSER TO THE SURFACE LOW). THE LACK OF INSTABILITY...ESPECIALLY IN THE HAIL GROWTH ZONE...WILL LIMIT THE POTENTIAL FOR LARGE HAIL (PERHAPS OUTSIDE OF A STRONGER / ROTATING UPDRAFT). THE THREAT FOR STRONG WINDS AND TORNADOES DOES APPEAR TO EXIST...BUT THE THERMODYNAMIC ENVIRONMENT SEEMS TO LIMIT THIS FROM BEING A HIGHER-END SEVERE EVENT. A CLOUDIER/GRUNGIER MORNING WOULD SUPPORT AN ISOLATED SEVERE THREAT WITH CLUSTERS OF STORMS CAPABLE OF STRONG WINDS AND MAYBE A BIT OF ROTATION. THE OUTSIDE SHOT FOR TODAY WOULD BE A GREATER DEAL OF BOUNDARY LAYER DESTABILIZATION (BETWEEN INSOLATION AND MOISTURE ADVECTION)...WHICH WOULD BRING A GREATER RISK OF ALL THE SEVERE MODES COMING TO THE TABLE. HOWEVER...GIVEN ALL THE EVIDENCE...THIS FORECAST WILL LEAN TOWARD THE FORMER SOLUTION. THE HWO WILL FOLLOW SUIT WITH A RELATIVELY TYPICAL-SOUNDING SEVERE THREAT WORDING. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... THE INITIAL COLD FRONT WILL BE CROSSING THE ILN CWA DURING THE EVENING HOURS...PRODUCING A RELATIVELY SMALL CHANGE IN THE TEMPERATURE AND WIND FIELDS. BEHIND THE FRONT...PRECIPITATION WILL BECOME LESS LIKELY...ESPECIALLY IN THE SOUTH AND SOUTHWEST PORTIONS OF THE CWA. A SECONDARY TROUGH (BOTH ALOFT AND AT THE SURFACE) WILL BE ROTATING SOUTHEAST THROUGH THE CWA ON THURSDAY. THIS WILL BRING A RENEWED CHANCE OF PRECIPITATION...ESPECIALLY IN THE NORTHERN AND EASTERN PARTS OF THE CWA. INSTABILITY WILL BE VERY WEAK...BUT JUST ENOUGH FOR SOME RISK OF THUNDER. THE AIR MASS ALOFT WILL BE INCREASINGLY COLD...HELPING TO LEAD TO THE POSSIBILITY OF CONVECTIVE SHOWERS. ALONG WITH THIS ACTIVITY WILL BE A SECONDARY COLD FRONT...MUCH BETTER DEFINED THAN THE FIRST. A NNW WIND SHIFT WILL ALLOW FOR COLD ADVECTION TO BEGIN ON THURSDAY (AND ESPECIALLY THURSDAY NIGHT). AS A RESULT...THE MAX TEMP GRADIENT FOR THURSDAY IS SOMEWHAT SHARP (ABOUT 10 DEGREES FROM SW TO NE) AND THURSDAY NIGHT MIN TEMPS MAY GET INTO THE 30S IN THE NORTHERN PORTIONS OF THE CWA. WITH DRY HIGH PRESSURE IN PLACE FOR FRIDAY...RELATIVELY TRANQUIL CONDITIONS ARE EXPECTED. && .LONG TERM /SATURDAY THROUGH TUESDAY/... DRY WEATHER SHOULD CONTINUE ON SATURDAY FOR MOST OF THE AREA EXCEPT FOR FAR SOUTHEAST COUNTIES WHERE A DEVELOPING FRONTAL BOUNDARY MAY CAUSE A FEW SHOWERS. FOR SUNDAY THROUGH TUESDAY...THAT FRONTAL BOUNDARY IS FORECAST TO LINGER ACROSS KENTUCKY. THIS PATTERN WILL PROVIDE A CHANCE OF SHOWERS EACH DAY TO THE SOUTHERN PART OF THE FORECAST AREA...WITH NORTHERN LOCATIONS ENJOYING A PERIOD OF DRY WEATHER. SLIGHTLY BELOW NORMAL HIGHS AVERAGING IN THE LOWER 70S ON THURSDAY WILL BE FOLLOWED BY BELOW NORMAL 60S ON FRIDAY UNDER CLOUDS AND SHOWERS. TEMPERATURES WILL THEN GRADUALLY REBOUND FROM SATURDAY ONWARD...WITH HIGHS REACHING THE MID AND UPPER 70S BY TUESDAY. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... REGION WILL REMAIN IN A MOIST SOUTH TO SOUTHWEST FLOW AT THE SURFACE AND ALOFT AS THE CENTER OF AN UPPER LEVEL LOW PIVOTS SOUTHEAST TOWARD THE WESTERN GREAT LAKES. AS THE LOW MOVES SOUTHEAST...A SURFACE COLD FRONT WILL PUSH EAST THROUGH OUR AREA TONIGHT. LATEST ANALYSIS AND MODELS INDICATE THAT OUR AREA IS IN AN INSTABILITY MINIMUM EARLY THIS MORNING. AS SUCH...THE LOW LEVEL JET THAT IS FORECAST TO DEVELOP OVERNIGHT SHOULD PRODUCE SOME SCATTERED SHOWERS AND PERHAPS A RUMBLE OF THUNDER. FOR TODAY INTO THIS EVENING...THE PROSPECTS OF SHOWERS AND THUNDERSTORMS WILL INCREASE THROUGH THE DAY AS DAYTIME HEATING INTERACTS WITH LARGE SCALE SYNOPTIC LIFT. BEST CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE FROM MID AFTERNOON INTO THE EVENING HOURS. HAVE PLACED THIS IN THE TAFS WITH A PREDOMINANT MVFR -SHRA AND A VCTS/CB. AS STORMS BECOME MORE APPARENT AND CAN BE TRACKED ON RADAR...TAFS WILL BE FINED TUNED ACCORDINGLY. WITH A MOIST AIRMASS...SOME LOCAL MVFR CIGS AND IFR VSBYS WILL BE POSSIBLE IN THUNDERSTORMS. DAYTIME HEATING/MIXING WILL PRODUCE SOUTH/SOUTHWEST WINDS OF 10-15 KNOTS WITH GUSTS AROUND 25 KNOTS. FOR TONIGHT...A COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE REGION. LARGE SCALE LIFT DECREASES AS DOES THE INSTABILITY. HOWEVER...MODELS INDICATE THAT THERE COULD BE A BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ALONG AND AHEAD OF THE FRONT. HAVE INDICATED THIS WITH A VCSH AS THUNDERSTORMS CHANCES WILL WANE BETWEEN 01Z AND 06Z. AFTER FRONTAL PASSAGE...THERE SHOULD BE A REPRIEVE IN PCPN BUT LOW LEVEL MOISTURE WILL LIKELY RESULT IN SOME MVFR CIGS. OUTLOOK...MVFR CONDITIONS POSSIBLE THURSDAY INTO THURSDAY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
412 AM EDT WED MAY 22 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES TODAY...WITH A COLD FRONT MOVING INTO THE OHIO VALLEY TONIGHT. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THIS FRONT. A SECONDARY TROUGH WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY. MUCH COLDER AIR WILL MOVE INTO THE REGION ON FRIDAY...AS HIGH PRESSURE BUILDS INTO THE OHIO VALLEY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SOMEWHAT-DISORGANIZED SURFACE LOW IS CURRENTLY LOCATED IN IOWA AND NORTHERN ILLINOIS. THIS LOW WILL SLOWLY MOVE TO THE EAST TODAY...STRENGTHENING SLIGHTLY AS IT CROSSES THE SOUTHERN GREAT LAKES. SOUTH OF THE LOW...A WEAK COLD FRONT WILL MOVE INTO THE ILN CWA BY EVENING. THIS FRONT IS TOUGH TO PICK OUT ON SURFACE TEMPERATURE FIELDS...BUT IS A BIT MORE EVIDENT WHEN EXAMINING THETA-E SLIGHTLY ALOFT...AND ALSO LOOKING FOR SLIGHT WIND SHIFT FROM SSW TO WSW. AT THE SAME TIME...A CLOSED UPPER LOW OVER THE NORTHERN MISSISSIPPI VALLEY WILL BEGIN ITS MOVE TO THE EAST...WITH A SHORTWAVE ROTATING NORTHEAST THROUGH INDIANA AND MICHIGAN. IN THE RIGHT ENTRANCE REGION OF AN UPPER JET...THE SETUP OVER OHIO WILL BE FAVORABLE FOR LARGE-SCALE LIFT. THE STANDARD SUITE OF MODELS (GFS/NAM/CMC/ECMWF) HAS THUS FAR APPEARED MUCH TOO AGGRESSIVE WITH THE OVERNIGHT PRECIPITATION FORECAST OVER ILLINOIS AND INDIANA. THIS IS ADMITTEDLY A REGION WHERE LIFT IS FORECAST TO CONTINUE TO ENHANCE THROUGH MORNING...IN A REGION OF FALLING HEIGHTS AND A 30-40 KNOT LLJ. DEWPOINTS NORTH OF THE CURRENT TENNESSEE CONVECTION ARE ABOUT 3-6 DEGREES LOWER THAN IN THE SOUTHERN STATES...BUT THE AIR MASS COULD NOT BE DESCRIBED AS PARTICULARLY DRY. AS WAS THE CASE YESTERDAY...THE HRRR HAS THE CLOSEST APPROXIMATION TO THE CURRENT ACTIVITY. SEVERAL OTHER CONVECTIVE-ALLOWING MODELS DEPICT QUITE A BIT OF CONVECTION MOVING INTO THE ILN CWA AS EARLY AS 12Z...WHICH DOES NOT APPEAR REALISTIC GIVEN THE LACK OF INSTABILITY AND CURRENT RADAR TRENDS. THE OVERALL CHANCES FOR RAIN IN THE ILN CWA DO NOT APPEAR PARTICULARLY HIGH THROUGH THE MORNING HOURS...THOUGH SLIGHTLY MORE SO IN THE WESTERN PART OF THE CWA. THE MAIN CONCERN FOR THE FORECAST TODAY IS THE POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON. GIVEN THE WIDE VARIANCE IN THE HANDLING OF THE CURRENT WEATHER SITUATION...AND THE FACT THAT THESE MESOSCALE FEATURES WILL BE VERY IMPORTANT IN CONVECTIVE FORECASTING FOR THIS AFTERNOON...IT IS TOUGH TO TRUST ANY OF THE SPECIFIC QPF/SIM-RADAR DEPICTIONS FOR THE AFTERNOON HOURS. TO BEGIN WITH THE BIGGEST LIMITING FACTOR FOR TODAY...INSTABILITY WILL BE IN QUESTION. GIVEN THE EXPECTED CLOUD COVER...AND EVEN PRECIPITATION IN SOME PLACES...THE SURFACE TEMP FORECAST IS ON THE LOW SIDE OF GUIDANCE. GIVEN THE THERMAL PROFILE...MLCAPE WILL STRUGGLE TO REACH 1000 J/KG...WITH THE MOST INSTABILITY FORECAST TO BE IN THE SOUTHEASTERN PARTS OF THE CWA. IN THE NORTHWEST...WHERE TEMPS WILL BE THE COOLEST...INSTABILITY WILL BE EVEN LESS (500 J/KG OR SO). SOUNDINGS ARE RELATIVELY MOIST THROUGH THEIR DEPTH...WITH RATHER LOW LCL HEIGHTS (AROUND 2000-3000 FEET AGL) FORECAST ON THE GFS/NAM (THE RAP13 APPEARS A BIT DRIER). BECAUSE OF THE MOIST CONDITIONS...THE CAPE PROFILE IS NARROW. UNLIKE YESTERDAY...THE OVERALL FORCING ENVIRONMENT WILL BE MORE FAVORABLE FOR CONVECTIVE DEVELOPMENT...EVEN IF INSTABILITY IS WEAK. WIND SHEAR IS ALSO SOMEWHAT OF A STRENGTH FOR TODAY...ALTHOUGH MODEL-TO-MODEL ASSESSMENT ON SHEAR VALUES IS NOT IN AS GOOD OF CONSENSUS AS IS USUALLY THE CASE. MOST OF THE SHEAR WILL BE FAIRLY UNIDIRECTIONAL (ALL IN THE TOP-RIGHT QUADRANT OF THE HODOGRAPH)...BUT WITH A DECENT CHANGE IN SPEED. 30-40 KNOTS OF DEEP LAYER SHEAR WILL BE PRESENT...WITH 15-25 KNOTS IN THE 0-1KM LAYER. 0-3KM SRH VALUES WILL GET INTO THE 100-200 RANGE...SO THERE WILL CERTAINLY BE SOME POTENTIAL FOR ROTATING STORMS. THIS COULD BE ENHANCED BY BOUNDARY INTERACTIONS OR AREAS OF BACKING SURFACE WINDS (PERHAPS FURTHER NORTH AND CLOSER TO THE SURFACE LOW). THE LACK OF INSTABILITY...ESPECIALLY IN THE HAIL GROWTH ZONE...WILL LIMIT THE POTENTIAL FOR LARGE HAIL (PERHAPS OUTSIDE OF A STRONGER / ROTATING UPDRAFT). THE THREAT FOR STRONG WINDS AND TORNADOES DOES APPEAR TO EXIST...BUT THE THERMODYNAMIC ENVIRONMENT SEEMS TO LIMIT THIS FROM BEING A HIGHER-END SEVERE EVENT. A CLOUDIER/GRUNGIER MORNING WOULD SUPPORT AN ISOLATED SEVERE THREAT WITH CLUSTERS OF STORMS CAPABLE OF STRONG WINDS AND MAYBE A BIT OF ROTATION. THE OUTSIDE SHOT FOR TODAY WOULD BE A GREATER DEAL OF BOUNDARY LAYER DESTABILIZATION (BETWEEN INSOLATION AND MOISTURE ADVECTION)...WHICH WOULD BRING A GREATER RISK OF ALL THE SEVERE MODES COMING TO THE TABLE. HOWEVER...GIVEN ALL THE EVIDENCE...THIS FORECAST WILL LEAN TOWARD THE FORMER SOLUTION. THE HWO WILL FOLLOW SUIT WITH A RELATIVELY TYPICAL-SOUNDING SEVERE THREAT WORDING. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... THE SHORT TERM DISCUSSION WILL BE UPDATED SHORTLY. PREVIOUS DISCUSSION FOLLOWS > SHOWERS AND THUNDERSTORMS WILL CONTINUE TO OVERSPREAD THE FA DURING THE DAYTIME HOURS ON WEDNESDAY. THERE IS STILL SOME QUESTION AS TO THE SEVERE POTENTIAL FOR WEDNESDAY. THERE IS BETTER INSTABILITY ACROSS EASTERN PORTIONS OF THE FA FOR WEDNESDAY. IN ADDITION STORMS WILL HOLD OFF A LITTLE LONGER ACROSS EASTERN PORTIONS OF THE FA WHICH WILL ALLOW FOR SOME MORE HEATING. DUE TO THIS BELIEVE THAT THE BETTER SEVERE THREAT WILL BE ACROSS EASTERN PORTIONS OF THE FA FOR WEDNESDAY WITH THE MAIN THREATS BEING DAMAGING WINDS AND LARGE HAIL. PRECIPITATION COVERAGE ACROSS THE AREA WILL DIMINISH DURING THE LATE EVENING HOURS HOWEVER SOME ISOLATED ACTIVITY WILL STILL REMAIN POSSIBLE. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BEGIN TO MOVE INTO WESTERN PORTIONS OF THE FA LATE IN THE OVERNIGHT HOURS WEDNESDAY NIGHT AS THE COLD FRONT APPROACHES THE AREA. && .LONG TERM /SATURDAY THROUGH TUESDAY/... SHOWERS ARE LIKELY TO DEVELOP MAINLY OVER NORTHERN LOCATIONS ON THURSDAY AS A SHARP UPPER TROUGH AND COOL AIRMASS PUSH THROUGH THE GREAT LAKES AND OHIO VALLEY. FRIDAY WILL BE DRY AND COOL WITH HIGH PRESSURE CROSSING THE AREA. DRY WEATHER SHOULD CONTINUE ON SATURDAY FOR MOST OF THE AREA EXCEPT FOR FAR SOUTHEAST COUNTIES WHERE A DEVELOPING FRONTAL BOUNDARY MAY CAUSE A FEW SHOWERS. FOR SUNDAY THROUGH TUESDAY...THAT FRONTAL BOUNDARY IS FORECAST TO LINGER ACROSS KENTUCKY. THIS PATTERN WILL PROVIDE A CHANCE OF SHOWERS EACH DAY TO THE SOUTHERN PART OF THE FORECAST AREA...WITH NORTHERN LOCATIONS ENJOYING A PERIOD OF DRY WEATHER. SLIGHTLY BELOW NORMAL HIGHS AVERAGING IN THE LOWER 70S ON THURSDAY WILL BE FOLLOWED BY BELOW NORMAL 60S ON FRIDAY UNDER CLOUDS AND SHOWERS. TEMPERATURES WILL THEN GRADUALLY REBOUND FROM SATURDAY ONWARD...WITH HIGHS REACHING THE MID AND UPPER 70S BY TUESDAY. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... REGION WILL REMAIN IN A MOIST SOUTH TO SOUTHWEST FLOW AT THE SURFACE AND ALOFT AS THE CENTER OF AN UPPER LEVEL LOW PIVOTS SOUTHEAST TOWARD THE WESTERN GREAT LAKES. AS THE LOW MOVES SOUTHEAST...A SURFACE COLD FRONT WILL PUSH EAST THROUGH OUR AREA TONIGHT. LATEST ANALYSIS AND MODELS INDICATE THAT OUR AREA IS IN AN INSTABILITY MINIMUM EARLY THIS MORNING. AS SUCH...THE LOW LEVEL JET THAT IS FORECAST TO DEVELOP OVERNIGHT SHOULD PRODUCE SOME SCATTERED SHOWERS AND PERHAPS A RUMBLE OF THUNDER. FOR TODAY INTO THIS EVENING...THE PROSPECTS OF SHOWERS AND THUNDERSTORMS WILL INCREASE THROUGH THE DAY AS DAYTIME HEATING INTERACTS WITH LARGE SCALE SYNOPTIC LIFT. BEST CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE FROM MID AFTERNOON INTO THE EVENING HOURS. HAVE PLACED THIS IN THE TAFS WITH A PREDOMINANT MVFR -SHRA AND A VCTS/CB. AS STORMS BECOME MORE APPARENT AND CAN BE TRACKED ON RADAR...TAFS WILL BE FINED TUNED ACCORDINGLY. WITH A MOIST AIRMASS...SOME LOCAL MVFR CIGS AND IFR VSBYS WILL BE POSSIBLE IN THUNDERSTORMS. DAYTIME HEATING/MIXING WILL PRODUCE SOUTH/SOUTHWEST WINDS OF 10-15 KNOTS WITH GUSTS AROUND 25 KNOTS. FOR TONIGHT...A COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE REGION. LARGE SCALE LIFT DECREASES AS DOES THE INSTABILITY. HOWEVER...MODELS INDICATE THAT THERE COULD BE A BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ALONG AND AHEAD OF THE FRONT. HAVE INDICATED THIS WITH A VCSH AS THUNDERSTORMS CHANCES WILL WANE BETWEEN 01Z AND 06Z. AFTER FRONTAL PASSAGE...THERE SHOULD BE A REPRIEVE IN PCPN BUT LOW LEVEL MOISTURE WILL LIKELY RESULT IN SOME MVFR CIGS. OUTLOOK...MVFR CONDITIONS POSSIBLE THURSDAY INTO THURSDAY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
1157 PM CDT TUE MAY 21 2013 .DISCUSSION... THE 06Z TAF DISCUSSION IS INCLUDED BELOW. && .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. CLOUDS WILL BE CLEARING SOON AT ALL OF THE TAF SITES...AND WITH THE SATURATED CONDITIONS NEAR THE GROUND...THERE WILL BE SOME FOG DEVELOPMENT. I THINK CONDITIONS WILL BE WORSE DOWN AT KMLC AND KFSM WHERE RECENT HEAVY RAINS HAVE OCCURRED. NEVERTHELESS...VSBYS WILL DROP DOWN TO IFR AND POSSIBLY LOWER FOR A TIME. VFR CONDITIONS WILL PREVAIL ON WEDNESDAY EVERYWHERE. LACY && .PREV DISCUSSION... /ISSUED 917 PM CDT TUE MAY 21 2013/ ..UPDATE... DISCUSSION... PRECIPITATION HAS MOVED EAST OUT OF THE ENTIRE FORECAST AREA QUICKLY THIS EVENING. SKIES ARE CLEARING FROM THE WEST AS DRY AIR PUSHES IN BEHIND THE DEPARTING UPPER SYSTEM. HAVE REMOVED POPS FOR ALL BUT THE EASTERN MOST SLIVER OF THE CWA. HAVE ALSO CLEARED SKIES A LITTLE FASTER OVERNIGHT. HAVE LEFT FORECAST MINIMUM TEMPERATURES AS THEY WERE. UPDATED PRODUCTS HAVE ALL BEEN SENT. PREV DISCUSSION... /ISSUED 648 PM CDT TUE MAY 21 2013/ DISCUSSION... THE 00Z TAF DISCUSSION IS INCLUDED BELOW. AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. RAIN/STORMS ARE MOVING OUT...WITH SKIES CLEARING THIS EVENING. DUE TO THE RECENT RAINS AND WET GROUND...SOME PATCHY FOG WILL LIKELY DEVELOP. THINK THE FOG WILL BE MOST PROMINENT OVER SOUTHEAST OK WHERE THE HEAVIEST RAINS FELL SO I HAVE BROUGHT KMLC DOWN TO IFR VSBY. THE HYDROLAPSE BECOMES UNFAVORABLE FOR WIDESPREAD DENSE FOG TONIGHT AS THE BOUNDARY LAYER DRIES OUT AFTER MIDNIGHT. SO FOR NOW STAYED CONSERVATIVE ON VSBYS AT THE OTHER SITES. LACY PREV DISCUSSION... /ISSUED 312 PM CDT TUE MAY 21 2013/ DISCUSSION... LINEAR MCS THAT HAS FORMED AHEAD OF COMPACT UPPER SYSTEM SURGING ACROSS OK/TX IS CURRENTLY MOVING ACROSS PORTIONS OF SERN OK. THE LINE HAS BEEN STRONG/MARGINALLY SEVERE SO FAR...AND STILL COULD SEE SOME 60+ MPH WIND GUSTS OVER THE NEXT FEW HOURS. HRRR HAS SHOWN A VERY GOOD HANDLE ON THE COMPLEX...WITH THE LEADING EDGE EXITING OUR FORECAST AREA AROUND 22Z-23Z. CURRENT FLASH FLOOD WATCH IS SET TO EXPIRE AT 00Z...ALTHOUGH MAY EXTEND IT A FEW MORE HOURS. WILL TAKE A LAST LOOK AT RADAR BEFORE FINAL DECISION. OTHERWISE...PARTIALLY CLEARING SKIES ALONG WITH DRIER LOW-LEVEL AIR WILL ALLOW TEMPS TO FALL INTO THE 50S FOR MUCH OF THE AREA. WEAK SURFACE BOUNDARY MAY BE PRESENT ACROSS THE AREA ON WEDNESDAY...ALTHOUGH ATMOSPHERE SHOULD BE TOO DRY AND WORKED OVER TO SUPPORT PRECIPITATION. UPPER PATTERN WILL BECOME INCREASINGLY AMPLIFIED BY MID-TO-LATE WEEK...WITH RIDGING THROUGH THE PLAINS SANDWICHED BY DEEP UPPER SYSTEMS ACROSS THE PAC NW AND THE EAST COAST. MODELS SUGGEST THAT SEVERAL WEAK WAVES WILL MOVE INTO THE MEAN RIDGE POSITION...WITH AT LEAST SOME LOW POPS WARRANTED ACROSS WRN SECTIONS IN THE VERY WARM/MOIST AIRMASS. UPPER RIDGE SHOULD FLATTEN SOME ACROSS THE SRN/CENTRL PLAINS GOING INTO THE WEEKEND. WITH THE FORECAST AREA ALONG THE SRN EDGE OF THE STRONGER UPPER FLOW...SHOULD SEE PERIODIC SHOWER/THUNDERSTORM EPISODES...ESPECIALLY ACROSS NE OK/NW AR. TOUGH TO PINPOINT WHICH DAY WILL HAVE THE BEST CHANCES...SO HAVE MAINTAINED GENERAL CHANCE POPS FOR ABOUT THE NRN HALF OF THE AREA FOR THE WEEKEND AND INTO EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... TUL 55 81 58 78 / 10 0 10 20 FSM 58 83 62 81 / 20 10 10 10 MLC 55 83 61 84 / 10 0 10 20 BVO 52 81 54 77 / 10 0 10 20 FYV 54 79 55 76 / 20 10 10 10 BYV 56 79 55 77 / 30 10 10 10 MKO 55 82 60 79 / 10 10 10 20 MIO 54 78 56 78 / 10 10 10 10 F10 55 82 61 79 / 10 0 10 20 HHW 60 85 64 85 / 10 0 10 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
506 PM EDT WED MAY 22 2013 .SYNOPSIS... AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... AS OF 430 PM...INCREASED POPS ACROSS THE UPSTATE OF SOUTH CAROLINA AND THE PIEDMONT OF NORTH CAROLINA DURING THE OVERNIGHT HOURS AS SHORT TERM CONVECTIVE MODEL GUIDANCE CONTINUES WIDESPREAD CONVECTION ACROSS THE ABOVE MENTIONED REGIONS THROUGH 10Z THURSDAY. ALSO TOUCHED UP SKY AND TEMP GRIDS. OTHERWISE...NO OTHER CHANGES WERE MADE. REMAINDER OF PREVIOUS DISCUSSION... AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY. FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD. THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE AFEW DEGREES COOLER. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS... AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR SO. A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5 TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR ANY PRECIPITATION. MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA... PARTICULARLY IN THE AFTERNOON. HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL HAVE TO MONITOR TRENDS. HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON TAP. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES. HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED. RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED. SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... AT KCLT FOR 21Z UPDATE...THINK CONDITIONS WILL REMAIN VFR INTO THE EARLY EVENING...WITH BKN CLOUD BASES AROUND THE 035 TO 045 RANGE. THE LATEST GUIDANCE...INCLUDING THE CONVECTIVE MODELS...IS FOCUSING MORE ON THE MID TO LATE EVENING ACROSS THE NC PIEDMONT FOR WHEN A BROKEN BAND OF STORMS WILL MOVE THROUGH. REMOVED PREVIOUS PROB30 AND WENT WITH A 4HR TEMPO GROUP FOR TSRA WITH MVFR VISB. THE FRONT SHOULD STAY WEST OF THE TERMINAL THROUGH EARLY AFTERNOON AND WILL SERVE AS A TRIGGER FOR NEW DEVELOPMENT BY LATE MORNING THURSDAY...THUS ANOTHER PROB30 GROUP TOWARD THE END OF THE PERIOD. AS A RESULT...WIND DIRECTION SHOULD REMAIN S TO SW. ELSEWHERE...VFR FOR THE TIME BEING. CONVECTIVE CLOUD BASES SHOULD REMAIN IN THE 035 TO 050 RANGE...MAINLY FEW TO SCT...AND THEN SHOULD DROP INTO THE MVFR RANGE THIS EVENING AS CONVECTION BECOMES MORE NUMEROUS. THE FRONT WILL PROBABLY MAKE IT INTO THE MTNS THURSDAY MORNING SO THE WIND AT KAVL WAS SHIFTED TO NW. ANOTHER ROUND OF SHOWERS AND STORMS IS POSSIBLE OVER NC THURSDAY LATE IN THE PERIOD. OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER FRIDAY AND SATURDAY. CONFIDENCE TABLE... 21-03Z 03-09Z 09-15Z 15-21Z KCLT HIGH 100% HIGH 87% HIGH 88% MED 79% KGSP HIGH 92% MED 71% HIGH 91% HIGH 100% KAVL MED 77% HIGH 81% HIGH 86% HIGH 100% KHKY HIGH 80% LOW 56% MED 72% HIGH 83% KGMU HIGH 92% MED 69% HIGH 88% HIGH 100% KAND HIGH 93% MED 74% HIGH 88% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...SBK NEAR TERM...CDG/PM/WIMBERLEY SHORT TERM...TS LONG TERM...SBK AVIATION...CDG/PM/WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
245 PM EDT WED MAY 22 2013 .SYNOPSIS... AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY. FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD. THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE AFEW DEGREES COOLER. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS... AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR SO. A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5 TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR ANY PRECIPITATION. MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA... PARTICULARLY IN THE AFTERNOON. HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL HAVE TO MONITOR TRENDS. HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON TAP. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES. HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED. RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED. SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... AT KCLT...THINK CONDITIONS WILL REMAIN VFR INTO THE EARLY EVENING...WITH SCT CLOUD BASES AROUND THE 035 TO 045 RANGE. THE LATEST GUIDANCE...INCLUDING THE CONVECTIVE MODELS...IS FOCUSING MORE ON THE MID TO LATE EVENING ACROSS THE NC PIEDMONT FOR WHEN A BROKEN BAND OF STORMS WILL MOVE THROUGH. WILL CARRY A PROB30 FOR THIS IN THE 03Z TO 06Z TIME FRAME. EXPECT ADJUSTMENTS TO THE PROB AND MIGHT HAVE TO INCLUDE A TEMPO LATER IN THE DAY. WITH COOLING...THE CLOUD BASES SHOULD FALL INTO MVFR RANGE LATE THIS EVENING AND STAY THERE THROUGH EARLY AFTERNOON ON THURSDAY. FOG COULD BECOME A PROBLEM AROUND DAYBREAK IF SIGNIFICANT RAIN HAPPENS LATE TONIGHT. OTHERWISE...THE VSBY WAS KEPT ABOVE 5 MILES. THE FRONT SHOULD STAY WEST OF THE TERMINAL THROUGH EARLY AFTERNOON AND WILL SERVE AS A TRIGGER FOR NEW DEVELOPMENT BY LATE MORNING THURSDAY...THUS ANOTHER PROB30 GROUP TOWARD THE END OF THE PERIOD. AS A RESULT...WIND DIRECTION SHOULD REMAIN S TO SW. ELSEWHERE...VFR FOR THE TIME BEING. CONVECTIVE CLOUD BASES SHOULD REMAIN IN THE 035 TO 050 RANGE...MAINLY FEW TO SCT...AND THEN SHOULD DROP INTO THE MVFR RANGE THIS EVENING AS CONVECTION BECOMES MORE NUMEROUS. THE FRONT WILL PROBABLY MAKE IT INTO THE MTNS THURSDAY MORNING SO THE WIND AT KAVL WAS SHIFTED TO NW. ANOTHER ROUND OF SHOWERS AND STORMS IS POSSIBLE OVER NC THURSDAY LATE IN THE PERIOD. OUTLOOK... CEILING AND VISIBILITY RESTRICTIONS IN SCATTERED SHOWERS AND THUNDERSTORMS AGAIN THURSDAY AFTN/EVE. GENERALLY VFR WEATHER FRIDAY AND SATURDAY. CONFIDENCE TABLE... 18-24Z 00-06Z 06-12Z 12-18Z KCLT HIGH 86% HIGH 100% HIGH 86% HIGH 90% KGSP HIGH 100% MED 79% HIGH 87% HIGH 97% KAVL HIGH 93% MED 77% HIGH 81% HIGH 97% KHKY HIGH 93% MED 73% LOW 54% HIGH 80% KGMU HIGH 100% MED 79% HIGH 83% HIGH 94% KAND HIGH 100% HIGH 80% HIGH 82% HIGH 95% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...SBK NEAR TERM...PM SHORT TERM...TS LONG TERM...SBK AVIATION...PM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
205 PM CDT WED MAY 22 2013 .MESOSCALE UPDATE...FOR THIS AFTERNOON AND EVENING... VIS SATELLITE IMAGERY CONTINUES TO SHOW A BROKEN CLOUD DECK OVER MIDDLE TN THAT HAS BEEN LIMITING DIURNAL HEATING UNTIL THE LAST HOUR OR SO. WITH THE CLOUD DECK DETERIORATING ENOUGH TO ALLOW SUNLIGHT TO POKE THROUGH...INSTABILITY AND LOW LEVEL THERMODYNAMICS ARE INCREASING. SPC MESOANALYSIS SHOWS A 3 HOUR CAPE CHANGE ACROSS MUCH OF THE MID STATE OF ABOUT 400-600 J/KG WITH A CORRESPONDING DECREASE IN CONVECTIVE INHIBITION. FORECAST CAPE VALUES APPEAR TO BE BEST OUT EAST ON THE CUMBERLAND BUT GREATER THAN 1500 J/KG ACROSS THE MID STATE. FORECAST SOUNDINGS ARE UNCAPPED WITH STRONG LOW LEVEL LAPSE RATES AS WELL. RUC FORECAST SOUNDINGS SHOW CONVECTIVE TEMPERATURES BEING REACHED BETWEEN NOW AND THE NEXT HOUR SO EXPECT INITIATION OF CONVECTION TO BEGIN VERY SOON. DYNAMICALLY SPEAKING...UPPER LEVEL FORCING IS INCREASING ASSOCIATED WITH HEIGHT FALLS OVER WESTERN TENNESSEE. THE BEST UPPER LEVEL SUPPORT IS COINCIDENT WITH THE RRQ OF THE NEGATIVELY TILTED 300 MB LOW. AS THIS SHORTWAVE CONTINUES TO SWING AROUND AND AMPLIFY THE UPPER LEVEL LIFT IN ASSOCIATION WITH THE LOW...THE POSSIBILITY FOR SEVERE HAIL AND WINDS WILL INCREASE. EXPECT ISOLATED TO SCATTERED STRONG TO POSSIBLY SEVERE STORMS BEGIN OUT EAST WHERE BETTER THERMODYNAMIC INSTABILITY IS BEST. IN THE NEXT FEW HOURS AS LOCATIONS OUT WEST CONTINUE TO DESTABILIZE...THE FOCUS FOR SEVERE POTENTIAL WILL TRANSITION TO THE FRONT WHERE UPPER LEVEL SUPPORT AND SHEAR IS BEST. BELIEVE LARGE HAIL AND DAMAGING STRAIGHT LINE WINDS ARE THE BIGGEST THREATS. && .PREV DISCUSSION... /ISSUED 1137 AM CDT WED MAY 22 2013/ AVIATION 18Z DISCUSSION... WELL STACKED TROUGH TO PASS EASTWARD THROUGH THE MID STATE TODAY. CONVECTION EXPECTED TO DEVELOP WITH THE BEST COVERAGE ACROSS EASTERN MIDDLE TN. A FEW STORMS COULD REACH STRONG TO SEVERE LIMITS. AFT 00Z...CONVECTION WILL DIMINISH BUT CLOUDINESS AND SOME LATE NIGHT FOG WILL PERSIST. REDUCED VSBYS AND CIGS AOB 1KFT WILL OCCUR AT CSV AFT 06Z. IMPROVING CONDITIONS AREA WIDE AFT 12Z. PREV DISCUSSION... /ISSUED 1037 AM CDT WED MAY 22 2013/ UPDATE... HAVE UPDATED THE FORECAST TO PROVIDE A LITTLE BETTER TIMING OF THE EXPECTED CONVECTION THIS AFTN. REST OF THE FCST APPEARS IN GOOD SHAPE. MORNING UA ANALYSIS DEPICTS A SEASONALLY STRONG SOMEWHAT NEGATIVELY TILTED MID LVL SHORT WAVE ACRS ARKANSAS APPROACHING THE AREA. THE REGION IS ALSO ENTERING THE RR QUAD OF A RELATIVELY STRONG UPPER LVL JET STREAK WHICH WILL ENHANCE LIFT THIS AFTERNOON. THERMODYNAMICS DON`T LOOK ALL THAT IMPRESSIVE RIGHT NOW AS THE ATMOS IS PRETTY WORKED OVER AND A FAIR AMOUNT OF DEBRIS CLOUD HAS HUNG ARND. MORNING SOUNDING DEPICTS A DEEP DRY/CAPPED LOWER ATMOSPHERE THAT IS INHIBITING ANY DEVELOPMENT. DO EXPECT A LITTLE MORE SUN TO DEVELOP...AND A SLOW INCRS IN LLVL MSTR IS STILL ANTICIPATED. THE COMBINATION OF COOLING MID LVL TEMPS AND A WARMING/MOISTENING LOWER ATMOS WILL ALLOW CONVECTION TO INITIATE MOST LIKELY RIGHT ALONG A COLD FRONT PROGGED TO CROSS THE AREA IN THE MID/LATE AFTN. DECENT SPEED SHEAR IN PLACE SO EXPECT ACTIVITY TO ORIENT IN A LINE WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE. SPC CONTINUES A VERY LOW CHANCE OF A TORNADO AS WELL. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1137 AM CDT WED MAY 22 2013 .AVIATION 18Z DISCUSSION... WELL STACKED TROUGH TO PASS EASTWARD THROUGH THE MID STATE TODAY. CONVECTION EXPECTED TO DEVELOP WITH THE BEST COVERAGE ACROSS EASTERN MIDDLE TN. A FEW STORMS COULD REACH STRONG TO SEVERE LIMITS. AFT 00Z...CONVECTION WILL DIMINISH BUT CLOUDINESS AND SOME LATE NIGHT FOG WILL PERSIST. REDUCED VSBYS AND CIGS AOB 1KFT WILL OCCUR AT CSV AFT 06Z. IMPROVING CONDITIONS AREA WIDE AFT 12Z. && .PREV DISCUSSION... /ISSUED 1037 AM CDT WED MAY 22 2013/ UPDATE... HAVE UPDATED THE FORECAST TO PROVIDE A LITTLE BETTER TIMING OF THE EXPECTED CONVECTION THIS AFTN. REST OF THE FCST APPEARS IN GOOD SHAPE. MORNING UA ANALYSIS DEPICTS A SEASONALLY STRONG SOMEWHAT NEGATIVELY TILTED MID LVL SHORT WAVE ACRS ARKANSAS APPROACHING THE AREA. THE REGION IS ALSO ENTERING THE RR QUAD OF A RELATIVELY STRONG UPPER LVL JET STREAK WHICH WILL ENHANCE LIFT THIS AFTERNOON. THERMODYNAMICS DON`T LOOK ALL THAT IMPRESSIVE RIGHT NOW AS THE ATMOS IS PRETTY WORKED OVER AND A FAIR AMOUNT OF DEBRIS CLOUD HAS HUNG ARND. MORNING SOUNDING DEPICTS A DEEP DRY/CAPPED LOWER ATMOSPHERE THAT IS INHIBITING ANY DEVELOPMENT. DO EXPECT A LITTLE MORE SUN TO DEVELOP...AND A SLOW INCRS IN LLVL MSTR IS STILL ANTICIPATED. THE COMBINATION OF COOLING MID LVL TEMPS AND A WARMING/MOISTENING LOWER ATMOS WILL ALLOW CONVECTION TO INITIATE MOST LIKELY RIGHT ALONG A COLD FRONT PROGGED TO CROSS THE AREA IN THE MID/LATE AFTN. DECENT SPEED SHEAR IN PLACE SO EXPECT ACTIVITY TO ORIENT IN A LINE WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE. SPC CONTINUES A VERY LOW CHANCE OF A TORNADO AS WELL. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1037 AM CDT WED MAY 22 2013 .UPDATE... HAVE UPDATED THE FORECAST TO PROVIDE A LITTLE BETTER TIMING OF THE EXPECTED CONVECTION THIS AFTN. REST OF THE FCST APPEARS IN GOOD SHAPE. MORNING UA ANALYSIS DEPICTS A SEASONALLY STRONG SOMEWHAT NEGATIVELY TILTED MID LVL SHORT WAVE ACRS ARKANSAS APPROACHING THE AREA. THE REGION IS ALSO ENTERING THE RR QUAD OF A RELATIVELY STRONG UPPER LVL JET STREAK WHICH WILL ENHANCE LIFT THIS AFTERNOON. THERMODYNAMICS DON`T LOOK ALL THAT IMPRESSIVE RIGHT NOW AS THE ATMOS IS PRETTY WORKED OVER AND A FAIR AMOUNT OF DEBRIS CLOUD HAS HUNG ARND. MORNING SOUNDING DEPICTS A DEEP DRY/CAPPED LOWER ATMOSPHERE THAT IS INHIBITING ANY DEVELOPMENT. DO EXPECT A LITTLE MORE SUN TO DEVELOP...AND A SLOW INCRS IN LLVL MSTR IS STILL ANTICIPATED. THE COMBINATION OF COOLING MID LVL TEMPS AND A WARMING/MOISTENING LOWER ATMOS WILL ALLOW CONVECTION TO INITIATE MOST LIKELY RIGHT ALONG A COLD FRONT PROGGED TO CROSS THE AREA IN THE MID/LATE AFTN. DECENT SPEED SHEAR IN PLACE SO EXPECT ACTIVITY TO ORIENT IN A LINE WITH DAMAGING STRAIGHT LINE WINDS POSSIBLE. SPC CONTINUES A VERY LOW CHANCE OF A TORNADO AS WELL. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ JOHNSTONE
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
540 AM CDT WED MAY 22 2013 .UPDATE... 12Z TAF DISCUSSION. && .AVIATION... RADAR IMAGERY SHOWS MOST RECENT MCS HAS COLLAPSED WITH JUST A FEW REMAINING -TSRA APPROACHING CSV. BY 12Z TAF ISSUANCE TIME...ALL PRECIP SHOULD BE EAST OF AIRPORTS WITH DRY AND VFR CONDITIONS EXPECTED THROUGH THE MORNING. LAMP GUIDANCE INDICATES GUSTY SOUTHWEST WINDS TODAY WITH SPEEDS 5-12 KTS AND GUSTS TO 15-25 KTS. SHORTWAVE TROUGH ON WATER VAPOR IMAGERY OVER OKLAHOMA WILL SWING ACROSS THE REGION LATER TODAY PRODUCING ANOTHER ROUND OF SHOWERS AND STORMS IN THE AFTERNOON. DUE TO UNCERTAINTY ON COVERAGE WILL ONLY MENTION VCTS AT CKV/BNA BUT TEMPO -TSRA AT CSV. MUCH DRIER AIR ALOFT WILL FILTER IN BY 23/00Z WITH LESS CLOUD COVER AND SOME PATCHY FOG POSSIBLE LATE IN TAF PERIOD. 55 && .PREV DISCUSSION... /ISSUED 246 AM CDT WED MAY 22 2013/ DISCUSSION... CURRENT SETUP...UPPER TROUGH TAKING ON NEGATIVE TILT THROUGH THE MID- LEVELS BASED ON LATEST RUC WITH THE COLDER AIR ALOFT REMAINING BACK OVER CENTRAL PLAINS NOSING DOWN INTO ARKANSAS. A 35 TO 40 KNOT LOW LEVEL JET WAS CONTINUING TO FEED MOIST PLUME INTO MIDDLE TENNESSEE. WIND FIELD LOOKS TO BE UNIDIRECTIONAL WITH SPEED SHEAR IN THE LOWER TROPOSPHERE. UPPER LEVEL JET JUST RUNNING NORTH TO SOUTH FROM ABOUT TEXARKANA NORTHWARD INTO IOWA WITH A 65 KNOT MID LEVEL JET CUTTING ACROSS CENTRAL ARKANSAS. ON-GOING CONVECTION CURRENTLY ACROSS FAR WESTERN KENTUCKY...WESTERN TENNESSEE AND DOWN THROUGH MISSISSIPPI...BEEN SHOWING SIGNS OF WEAKENING LAST COUPLE OF HOURS AS CLOUD TOPS CONTINUE TO WARM. WITH THE CURRENT SETUP LOOKS LIKE SHOWERS AND STORMS WILL BE LIKELY DURING THE DAY...WITH A FEW STRONG TO SEVERE STORMS POSSIBLE...ESPECIALLY MID-DAY THROUGH THE AFTERNOON AND INTO THE EARLY EVENING HOURS. THINK THE MAIN THREAT WILL BE DAMAGING WINDS AND LARGE HAIL BUT ISOLATED TORNADOES ARE ALSO POSSIBLE. EVEN THOUGH THE WIND FIELDS ARE UNIDIRECTIONAL THE SWEAT INDEX CLIMBS TO 362 AT 18Z AND 413 BY 00Z WITH MID-LEVEL DRYING IN PLACE DURING THE MID-DAY THROUGH THE AFTERNOON/EARLY EVENING. ON THURSDAY A SHORT WAVE ON THE BACK SIDE OF UPPER TROUGH WILL DROP DOWN THROUGH THE OHIO VALLEY AND BRING A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS MAINLY TO THE NORTHEAST HALF DURING THE AFTERNOON WITH A SLIGHT CHANCE REMAINING ALONG THE PLATEAU THURSDAY NIGHT. MUCH OF THE MEMORIAL DAY WEEKEND LOOKS DRY HOWEVER MODELS HAVE BEEN DIFFERING. GFS HAS WARM FRONT DRAPED ACROSS THE OHIO VALLEY THROUGH THE WEEKEND WHICH WOULD KEEP MID STATE BASICALLY WARM AND DRY. THE EURO HAS WARM FRONT DRAPED THROUGH WESTERN TENNESSEE INTO NORTHERN ALABAMA AND KEEPS SHOWERS AND STORMS IN THE MID STATE JUST ABOUT EACH DAY THROUGH THE MEMORIAL DAY WEEKEND. HAVE OPTED TO GO WITH GFS FOR THIS FORECAST PACKAGE. HAVE BACKED OFF A TAD FROM MAV MOS ON HIGHS TODAY AND WENT CLOSER TO THE MET DUE TO CLOUD COVER AND SHOWER/STORM CHANCES. STAYED CLOSE TO MOS GUIDANCE THROUGH REMAINDER OF FORECAST. BOYD && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
246 AM CDT WED MAY 22 2013 .DISCUSSION... CURRENT SETUP...UPPER TROUGH TAKING ON NEGATIVE TILT THROUGH THE MID- LEVELS BASED ON LATEST RUC WITH THE COLDER AIR ALOFT REMAINING BACK OVER CENTRAL PLAINS NOSING DOWN INTO ARKANSAS. A 35 TO 40 KNOT LOW LEVEL JET WAS CONTINUING TO FEED MOIST PLUME INTO MIDDLE TENNESSEE. WIND FIELD LOOKS TO BE UNIDIRECTIONAL WITH SPEED SHEAR IN THE LOWER TROPOSPHERE. UPPER LEVEL JET JUST RUNNING NORTH TO SOUTH FROM ABOUT TEXARKANA NORTHWARD INTO IOWA WITH A 65 KNOT MID LEVEL JET CUTTING ACROSS CENTRAL ARKANSAS. ON-GOING CONVECTION CURRENTLY ACROSS FAR WESTERN KENTUCKY...WESTERN TENNESSEE AND DOWN THROUGH MISSISSIPPI...BEEN SHOWING SIGNS OF WEAKENING LAST COUPLE OF HOURS AS CLOUD TOPS CONTINUE TO WARM. WITH THE CURRENT SETUP LOOKS LIKE SHOWERS AND STORMS WILL BE LIKELY DURING THE DAY...WITH A FEW STRONG TO SEVERE STORMS POSSIBLE...ESPECIALLY MID-DAY THROUGH THE AFTERNOON AND INTO THE EARLY EVENING HOURS. THINK THE MAIN THREAT WILL BE DAMAGING WINDS AND LARGE HAIL BUT ISOLATED TORNADOES ARE ALSO POSSIBLE. EVEN THOUGH THE WIND FIELDS ARE UNIDIRECTIONAL THE SWEAT INDEX CLIMBS TO 362 AT 18Z AND 413 BY 00Z WITH MID-LEVEL DRYING IN PLACE DURING THE MID-DAY THROUGH THE AFTERNOON/EARLY EVENING. ON THURSDAY A SHORT WAVE ON THE BACK SIDE OF UPPER TROUGH WILL DROP DOWN THROUGH THE OHIO VALLEY AND BRING A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS MAINLY TO THE NORTHEAST HALF DURING THE AFTERNOON WITH A SLIGHT CHANCE REMAINING ALONG THE PLATEAU THURSDAY NIGHT. MUCH OF THE MEMORIAL DAY WEEKEND LOOKS DRY HOWEVER MODELS HAVE BEEN DIFFERING. GFS HAS WARM FRONT DRAPED ACROSS THE OHIO VALLEY THROUGH THE WEEKEND WHICH WOULD KEEP MID STATE BASICALLY WARM AND DRY. THE EURO HAS WARM FRONT DRAPED THROUGH WESTERN TENNESSEE INTO NORTHERN ALABAMA AND KEEPS SHOWERS AND STORMS IN THE MID STATE JUST ABOUT EACH DAY THROUGH THE MEMORIAL DAY WEEKEND. HAVE OPTED TO GO WITH GFS FOR THIS FORECAST PACKAGE. HAVE BACKED OFF A TAD FROM MAV MOS ON HIGHS TODAY AND WENT CLOSER TO THE MET DUE TO CLOUD COVER AND SHOWER/STORM CHANCES. STAYED CLOSE TO MOS GUIDANCE THROUGH REMAINDER OF FORECAST. BOYD && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 79 61 78 52 / 60 30 20 10 CLARKSVILLE 76 58 76 49 / 60 20 20 10 CROSSVILLE 76 59 73 51 / 70 50 30 20 COLUMBIA 79 61 80 54 / 60 30 20 10 LAWRENCEBURG 78 60 80 55 / 60 30 20 10 WAVERLY 77 59 77 50 / 60 20 20 10 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BOYD 01
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1242 AM CDT WED MAY 22 2013 .DISCUSSION...SEE AVIATION SECTION FOR 06Z TAFS. && .AVIATION...LOOP OF KCRP RADAR SHOWS OUTFLOW BOUNDARY/FRONT MOVING SOUTH AT 20 MPH INTO THE VICTORIA CROSSROADS REGION. LOW STRATUS HAS MOVED INTO THE COASTAL PLAINS WITH CEILINGS RANGING FROM IFR IN THE COASTAL BEND TO LOW END MVFR IN THE VICTORIA CROSSROADS. EXPECT THE BOUNDARY WILL STALL BEFORE MOVING INTO THE COASTAL WATERS OR COASTAL BEND LATER DURING THE OVERNIGHT. EAST-SOUTHEASTERLY LOW LEVEL FLOW WILL PUSH LOW CLOUDS WESTWARD INTO THE BRUSH COUNTRY REACHING LRD AREA BY 09Z. ONLY PLACED A MENTION OF LIGHT SHOWERS IN THE VCT TAF BEHIND THE FRONT EARLY THIS MORNING. MVFR CEILINGS WILL SLOWLY LIFT DURING THE MORNING HOURS AND SCATTER OUT BY 18Z AREA-WIDE. VFR CONDS WILL EXIST INTO THE EVENING HOURS WEDNESDAY WITH MVFR CIGS RETURNING TO THE COASTAL PLAINS BY 02-03Z THURSDAY. && .PREV DISCUSSION... /ISSUED 906 PM CDT TUE MAY 21 2013/ DISCUSSION...CONVECTION HAS FAILED TO DEVELOP AS OF WRITING AS SSW FLOW FROM H95 TO H7, PER 00Z AREA RAOBS, IS LIKELY NEGATING CONVECTIVE DEVELOPMENT. LATEST AVAILABLE HRRR AND 18Z TTU WRF ALSO INDICATE ONLY LOW CHANCES OF PRECIP DEVELOPING TONIGHT. THUS...HAVE LOWERED POPS FOR TONIGHT AREAWIDE. STILL THINK A THIN BAND OF SHOWERS AND A FEW RUMBLES OF THUNDER WILL DEVELOP OVERNIGHT...PRIMARILY ACROSS NORTHERN AND NE ZONES. WILL CONTINUE TO MONITOR SITUATION THROUGH THE NIGHT. OTHERWISE...ONLY OTHER CHANGE OF SIGNIFICANCE WAS TO INCLUDE MENTION OF HAZE AND SMOKE FARTHER INLAND TONIGHT AS SMOKE FROM AGRICULTURAL FIRES OVER STATE OF YUCATAN MEX CONTINUES TO IMPACT S TX. AIR PARTICULATES WILL LIKELY POOL ALONG STALLING WEAK SFC FRONT ACROSS NORTHERN ZONES TONIGHT RESULTING IN A CONTINUATION OF HAZE/SMOKINESS THROUGH WEDNESDAY. UPDATED PRODUCTS TO BE SENT SHORTLY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 75 92 75 91 76 / 10 10 10 10 10 VICTORIA 73 90 74 89 73 / 10 10 10 10 10 LAREDO 76 98 75 96 75 / 10 10 10 10 10 ALICE 73 93 75 91 75 / 10 10 10 10 10 ROCKPORT 75 86 75 85 76 / 10 10 10 10 10 COTULLA 73 98 74 96 74 / 10 10 10 10 10 KINGSVILLE 74 92 75 91 75 / 10 10 10 10 10 NAVY CORPUS 75 84 75 84 75 / 10 10 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ TMT/89...AVIATION
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AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
148 PM EDT WED MAY 22 2013 .SYNOPSIS... A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH PRESSURE ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 135 PM EDT WEDNESDAY... ADJUSTED POPS ACROSS TO LATEST RADAR TRENDS WITH CONVECTION DEVELOPING OVER THE MOUNTAINS. AS OF 925 AM EDT WEDNESDAY... ADJUSTED POPS FOR LATEST RADAR TREND...SHAPING POPS THIS MORNING INTO TOWARDS LATEST RNK WRFARW. KEPT THE BEST CHANCE FOR THUNDERSTORMS THIS AFTERNOON IN THE WEST. SWODY1 HAS PLACED A SLIGHT RISK JUST TO OUR WEST. MORNING RUN SHOWED THE POTENTIAL FOR LINE OF CONVECTION REACHING THE WEST BETWEEN 00Z AND 06Z TONIGHT. WILL REVIEW 12Z RUN BEFORE MAKING ANY MAJOR ADJUSTMENTS FOR TONIGHT. MODIFIED TEMPERATURES AND DEW POINTS THIS MORNING INTO THIS AFTERNOON. RAISED HIGH TEMPERATURES UP A FEW DEGREES IN SOUTHEAST. UPDATED FIRE WEATHER GRIDS...FWFRNK OUT. ADDITIONAL CHANGES LATER TODAY. AS OF 340 AM EDT WEDNESDAY... A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA. HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON. EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN 00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY THIS EVENING TO COVER THIS POTENTIAL. THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF OUR REGION TODAY INTO TONIGHT. CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID 60S SE. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 320 AM EDT WEDNESDAY... A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY. OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE. LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF VA/NC. THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO THE LOWER TO MID 70S EAST. FRIDAY NIGHT AND SATURDAY: QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 PM EDT TUESDAY FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY THE END OF THE PERIOD. WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING. THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING SOAKED AGAIN MONDAY-WEDNESDAY. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 140 PM EDT WEDNESDAY... SCATTERED MVFR/IFR CONVECTION DEVELOPING IN THE WARM UNSTABLE AIR ACROSS CWA THIS AFTERNOON. THE BEST CHANCE OF THUNDERSTORMS WILL OCCUR ACROSS WESTERN TAF SITES OF BLF/LWB/RNK. RNKWRF ARW SHOWED GOOD COVERAGE OF STORM ACROSS THE MOUNTAINS THIS AFTERNOON INTO TONIGHT. ECMWF/GFS GENERALLY CONSISTENT ON A LINE OF STRONG THUNDERSTORMS MOVING INTO FAR SW VA FROM KY/TN IN THE 00Z-04Z TIME FRAME...THEN GENERALLY DISSIPATING AS MOVE EAST. FOR THE EAST... THERE IS POTENTIAL TSRA DEVELOPMENT ACROSS THE NC PIEDMONT...LIFTING NORTHWARD TOWARD LYH/DAN/EVEN ROA BY LATE AFTERNOON INTO THIS EVENING. S-SW WINDS 5-10KTS THROUGH TAF VALID PERIOD...WITH LOW END GUSTS ACROSS THE PIEDMONT. AREAS OF FOG WILL DEVELOP TONIGHT INTO WEDNESDAY MORNING WHERE RAIN FALLS THIS AFTERNOON INTO THIS EVENING. MEDIUM TO HIGH CONFIDENCE IN CIGS/VSBYS THROUGH TAF VALID PERIOD. HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/JH/KK SHORT TERM...WP LONG TERM...WP AVIATION...KK/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
940 AM EDT WED MAY 22 2013 .SYNOPSIS... A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH PRESSURE ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 925 AM EDT WEDNESDAY... ADJUSTED POPS FOR LATEST RADAR TREND...SHAPING POPS THIS MORNING INTO TOWARDS LATEST RNK WRFARW. KEPT THE BEST CHANCE FOR THUNDERSTORMS THIS AFTERNOON IN THE WEST. SWODY1 HAS PLACED A SLIGHT RISK JUST TO OUR WEST. MORNING RUN SHOWED THE POTENTIAL FOR LINE OF CONVECTION REACHING THE WEST BETWEEN 00Z AND 06Z TONIGHT. WILL REVIEW 12Z RUN BEFORE MAKING ANY MAJOR ADJUSTMENTS FOR TONIGHT. MODIFIED TEMPERATURES AND DEW POINTS THIS MORNING INTO THIS AFTERNOON. RAISED HIGH TEMPERATURES UP A FEW DEGREES IN SOUTHEAST. UPDATED FIRE WEATHER GRIDS...FWFRNK OUT. ADDITIONAL CHANGES LATER TODAY. AS OF 340 AM EDT WEDNESDAY... A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA. HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON. EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN 00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY THIS EVENING TO COVER THIS POTENTIAL. THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF OUR REGION TODAY INTO TONIGHT. CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID 60S SE. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 320 AM EDT WEDNESDAY... A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY. OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE. LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF VA/NC. THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO THE LOWER TO MID 70S EAST. FRIDAY NIGHT AND SATURDAY: QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 PM EDT TUESDAY FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY THE END OF THE PERIOD. WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING. THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING SOAKED AGAIN MONDAY-WEDNESDAY. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 745 AM EDT WEDNESDAY... PATCHY FOG WILL DISSIPATE QUICKLY...ALTHOUGH IFR CIGS MAY LINGER ACROSS THE PIEDMONT FROM DAN-LYH FOR A WHILE THIS MORNING. OTHERWISE...MOSTLY VFR AFT 14Z WITH SC/CU DEVELOPING FROM EARLY MORNING MOISTURE. MAIN CONCERN WILL COME LATE TODAY AS THE STRONG COLD FRONT RESPONSIBLE FOR ALL OF THE SEVERE WEATHER IN THE MIDWEST RECENTLY APPROACHES THE AREA FROM THE WEST. ECMWF/GFS GENERALLY CONSISTENT ON A LINE OF STRONG THUNDERSTORMS MOVING INTO FAR SW VA FROM KY/TN IN THE 00Z-04Z TIME FRAME...THEN GENERALLY DISSIPATING AS IT MOVES TOWARD THE NEW RIVER VALLEY REGION...SIMILAR TIMING TO WHAT WE SAW YESTERDAY...BUT EXPECT ACTIVITY TO BE A LITTLE MORE POTENT THIS EVENING. DO NOT EXPECT THIS ACTIVITY TO SURVIVE AS IT REACHES THE PIEDMONT. HOWEVER...MODELS SHOW...ESPECIALLY THE GFS...POTENTIAL TSRA DEVELOPMENT ACROSS THE NC PIEDMONT...LIFTING NORTHWARD TOWARD LYH/DAN/EVEN ROA BY LATE AFTERNOON. HAVE PLAYED SOME POTENTIAL FOR THIS INTO THE TAFS. OTHERWISE...MOSTLY MVFR CIGS AND MVFR VSBYS IN VCTS AND/OR TSRA MOSTLY AFT 00Z...AGAIN LITTLE OF WHICH SHOULD REACH THE PIEDMONT. S-SW WINDS 5-10KTS THROUGH TAF VALID PERIOD...WITH LOW END GUSTS ACROSS THE PIEDMONT. MEDIUM TO HIGH CONFIDENCE IN CIGS/VSBYS THROUGH TAF VALID PERIOD. HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD. AS OF 202 AM EDT WEDNESDAY... THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE. THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED THIS MORNING. A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER SCTD/BKN 5-6K FT CU FIELDS. THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY. THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG. HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/RAB NEAR TERM...AMS/JH/KK SHORT TERM...WP LONG TERM...WP AVIATION...RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
750 AM EDT WED MAY 22 2013 .SYNOPSIS... A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH PRESSURE ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 340 AM EDT WEDNESDAY... A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA. HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON. EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN 00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY THIS EVENING TO COVER THIS POTENTIAL. THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF OUR REGION TODAY INTO TONIGHT. CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID 60S SE. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 320 AM EDT WEDNESDAY... A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY. OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE. LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF VA/NC. THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO THE LOWER TO MID 70S EAST. FRIDAY NIGHT AND SATURDAY: QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 PM EDT TUESDAY FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY THE END OF THE PERIOD. WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING. THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING SOAKED AGAIN MONDAY-WEDNESDAY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 745 AM EDT WEDNESDAY... PATCHY FOG WILL DISSIPATE QUICKLY...ALTHOUGH IFR CIGS MAY LINGER ACROSS THE PIEDMONT FROM DAN-LYH FOR A WHILE THIS MORNING. OTHERWISE...MOSTLY VFR AFT 14Z WITH SC/CU DEVELOPING FROM EARLY MORNING MOISTURE. MAIN CONCERN WILL COME LATE TODAY AS THE STRONG COLD FRONT RESPONSIBLE FOR ALL OF THE SEVERE WEATHER IN THE MIDWEST RECENTLY APPROACHES THE AREA FROM THE WEST. ECMWF/GFS GENERALLY CONSISTENT ON A LINE OF STRONG THUNDERSTORMS MOVING INTO FAR SW VA FROM KY/TN IN THE 00Z-04Z TIME FRAME...THEN GENERALLY DISSIPATING AS IT MOVES TOWARD THE NEW RIVER VALLEY REGION...SIMILAR TIMING TO WHAT WE SAW YESTERDAY...BUT EXPECT ACTIVITY TO BE A LITTLE MORE POTENT THIS EVENING. DO NOT EXPECT THIS ACTIVITY TO SURVIVE AS IT REACHES THE PIEDMONT. HOWEVER...MODELS SHOW...ESPECIALLY THE GFS...POTENTIAL TSRA DEVELOPMENT ACROSS THE NC PIEDMONT...LIFTING NORTHWARD TOWARD LYH/DAN/EVEN ROA BY LATE AFTERNOON. HAVE PLAYED SOME POTENTIAL FOR THIS INTO THE TAFS. OTHERWISE...MOSTLY MVFR CIGS AND MVFR VSBYS IN VCTS AND/OR TSRA MOSTLY AFT 00Z...AGAIN LITTLE OF WHICH SHOULD REACH THE PIEDMONT. S-SW WINDS 5-10KTS THROUGH TAF VALID PERIOD...WITH LOW END GUSTS ACROSS THE PIEDMONT. MEDIUM TO HIGH CONFIDENCE IN CIGS/VSBYS THROUGH TAF VALID PERIOD. HIGH CONFIDENCE IN WIND SPD/DIR THROUGH TAF VALID PERIOD. AS OF 202 AM EDT WEDNESDAY... THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE. THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED THIS MORNING. A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER SCTD/BKN 5-6K FT CU FIELDS. THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY. THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG. HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/JH/KK SHORT TERM...WP LONG TERM...WP AVIATION...RAB
AREA FORECAST DISCUSSION...ISSUED BY WFO RALEIGH NC
NWS BLACKSBURG VA
340 AM EDT WED MAY 22 2013 .SYNOPSIS... A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH PRESSURE ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 340 AM EDT WEDNESDAY... A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA. HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON. EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN 00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY THIS EVENING TO COVER THIS POTENTIAL. THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF OUR REGION TODAY INTO TONIGHT. CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID 60S SE. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... AS OF 320 AM EDT WEDNESDAY... A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY. OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE. LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF VA/NC. THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO THE LOWER TO MID 70S EAST. FRIDAY NIGHT AND SATURDAY: QUITE WEATHER IS EXPECTED TO RETURN FOR THE REST OF THE SHORT TERM FORECAST... WITH THE MID LEVEL TROUGH AXIS HAVING PUSHED TO THE EAST OF THE AREA BY FRIDAY EVENING AND HIGH PRESSURE AT THE SURFACE BUILDING INTO THE REGION FOR THIS TIME FRAME. THIS WILL YIELD GENERALLY COOL AND DRY CONDITIONS... WITH BELOW NORMAL TEMPS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 PM EDT TUESDAY FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY THE END OF THE PERIOD. WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING. THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING SOAKED AGAIN MONDAY-WEDNESDAY. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 202 AM EDT WEDNESDAY... THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE. THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED THIS MORNING. A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER SCTD/BKN 5-6K FT CU FIELDS. THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY. THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG. HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...PWB SHORT TERM...PWB/BSD/WP LONG TERM...WP AVIATION.../WFORAH
AREA FORECAST DISCUSSION...ISSUED BY WFO RALEIGH NC
NWS BLACKSBURG VA
320 AM EDT WED MAY 22 2013 .SYNOPSIS... A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH THE AREA THURSDAY INTO THURSDAY EVENING... FOLLOWED BY HIGH PRESSURE ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 320 AM EDT WEDNESDAY... A COUPLE OF CONCERNS TODAY. THE MAIN CONCERN IS WITH THE POTENTIAL FOR ISOLATED HEAVY RAIN IN THUNDERSTORMS THIS AFTERNOON. THE LOWEST FLASH FLOOD GUIDANCE IS CURRENTLY OBSERVED IN AREAS THAT HAVE RECEIVED HEAVY RAIN RECENTLY AND MOSTLY IN THE MOUNTAINS INCLUDING WATAUGA... ASHE... GRAYSON... INTO SMYTH AND TAZEWELL OF VA. HOWEVER... GIVEN THE EXPECTED SCATTERED NATURE OF THE CONVECTION THIS AFTERNOON... IT APPEARS THAT THE FLOODING THREAT WILL BE ISOLATED. THEREFORE... OPTED OUT OF A FLASH FLOOD WATCH AT THE CURRENT TIME. THE LATEST HI-RES MODELS INCLUDING THE HRRR INDICATE AT LEAST SCATTERED THUNDERSTORMS WILL DEVELOP OVER OUR REGION THIS AFTERNOON... PRIMARILY OVER THE MOUNTAINS AND FOOTHILLS SPREADING NE INTO THE VA PIEDMONT LATE THIS AFTERNOON AS WELL. WE WILL CONTINUE THE CHANCE CATEGORY POP FOR THOSE ZONES THIS AFTERNOON. EVEN MORE PROBLEMATIC MAY BE THE POSSIBLE LINE OF CONVECTION THAT THE HI-RES MODELS AND EVEN A FEW OF THE OPERATIONAL MODELS ARE PICKING UP ON ACROSS KY/TN THIS AFTERNOON. SOME OF THESE MODELS INDICATE A POTENTIAL MCS THAT MAY HOLD TOGETHER LONG ENOUGH TO SURGE INTO FAR SW VA... SOUTHERN WVA... AND POSSIBLY NORTHWEST NC BETWEEN 00Z AND 06Z TONIGHT. IT IS UNCLEAR HOW STRONG OR HOW FAST THIS CONVECTION WOULD BE AT THE CURRENT TIME. IF THIS APPEARS MORE LIKELY IN THE MODEL RUNS TODAY... THERE MAY BE A CONCERN WITH FLASH FLOODING THIS EVENING. WE WILL GO WITH HIGH CHANCE TO LOW END LIKELY THIS EVENING TO COVER THIS POTENTIAL. THE SLIGHT RISK FOR SEVERE CONVECTION CONTINUES TO BE JUST WEST OF OUR REGION TODAY INTO TONIGHT. CONDITIONS TODAY WILL BE WARM AND HUMID WITH THE SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. HIGHS TEMPERATURES SHOULD REACH THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST. LOWS TONIGHT WILL DIP BACK INTO THE 50S TO MID 60S SE. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 320 AM EDT WEDNESDAY... A LEAD SURFACE TROUGH OR CONVECTIVE OUTFLOW MAY AFFECT THE REGION BEFORE THE ACTUAL COLD FRONT ARRIVES THURSDAY. THIS MAY AFFECT THE CONVECTIVE CHANCES GREATLY AS THE MAIN COLD FRONT ARRIVES THURSDAY. OTHERWISE... A PERIOD OF LIKELY POP CAN BE EXPECTED WITH THE FRONT THURSDAY... POSSIBLY LASTING INTO THE EARLY EVENING AROUND DANVILLE. LACK OF HEATING THURSDAY... ESPECIALLY WEST OF THE BLUE RIDGE MAY ALSO LIMIT DESTABILIZATION. THE AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF VA/NC. THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO THE LOWER TO MID 70S EAST. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 PM EDT TUESDAY FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY THE END OF THE PERIOD. WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING. THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING SOAKED AGAIN MONDAY-WEDNESDAY. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 202 AM EDT WEDNESDAY... THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE. THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED THIS MORNING. A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER SCTD/BKN 5-6K FT CU FIELDS. THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY. THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG. HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...PWB SHORT TERM...PWB/WP LONG TERM...WP AVIATION.../WFORAH
AREA FORECAST DISCUSSION...ISSUED BY WFO RALEIGH NC
NWS BLACKSBURG VA
202 AM EDT WED MAY 22 2013 .SYNOPSIS... AN UPPER LEVEL AREA OF LOW PRESSURE WILL DRIFT EAST AND OFFSHORE OVERNIGHT. A LARGE LOW PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD FRONT THROUGH THE AREA THURSDAY...FOLLOWED BY HIGH PRESSURE ON FRIDAY. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 915 PM EDT TUESDAY... BAND OF WEAKENING CONVECTION ASSOCIATED WITH OLD OUTFLOW BAND TO THE WEST CONTINUES TO FADE ALONG THE WESTERN SLOPES ATTM WHILE NEW OUTFLOW HAS GIVEN RISE TO ADDED SHRA/TSRA OVER THE WESTERN RIDGES. LATEST MESO ANALYSIS SHOWS STILL ENOUGH INSTABILITY TO KEEP STORMS GOING A WHILE LONGER MOUNTAINS WITH SOME OF THIS COVERAGE PERHAPS DEVELOPING ACROSS THE BLUE RIDGE WHERE THE BEST LEFTOVER CAPES EXIST. APPEARS THE OVERALL SEVERE THREAT SHOULD SLOWLY FADE PER LOSS OF HEATING BUT LOW WET BULBS AND LOTS OF DRY AIR ALOFT OFF EVENING SOUNDINGS STILL SUPPORT AT LEAST ISOLATED SEVERE POTENTIAL THROUGH MIDNIGHT ESPCLY IF STORMS BECOME MORE LINEAR. THEREFORE NUDGED UP POPS TO LOW LIKELYS FAR WEST OVER THE NEW FEW HOURS WHILE KEEPING A SCATTERED NATURE FARTHER EAST DESPITE THE LACK OF COVERAGE OFF THE LATEST HRRR SHORTLY AFTER MIDNIGHT. LOW LEVELS ESPCLY EAST SHOW A BIT MORE DRYING THIS EVENING WITH SOME LIGHT MIXING ONGOING WHICH SHOULD SLOW DOWN FOG FORMATION UNTIL LATE EXCEPT WHERE RAINFALL HAS ALREADY OCCURRED. HOWEVER MOIST DEWPOINTS WILL HOLD TEMPS MOSTLY IN THE MUGGY 60S WITH ONLY THE DEEPER VALLEYS AND SPOTS SEEING SHOWERS PERHAPS FALLING INTO THE 50S LATE. WARM AND HUMID CONDITIONS CONTINUE ON WEDNESDAY IN THE SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING COLD FRONT AND UPPER TROUGH. INCREASED POPS FROM WEST TO EAST ON WEDNESDAY...WITH HIGHEST POPS ALONG WESTERN MOUNTAINS. THE SWODY2 (DAY TWO CONVECTIVE OUTLOOK) HAS THE SLIGHT RISK JUST TO OUR WEST ON WEDNESDAY. PLAYED HIGHS TEMPERATURES COOLER ON WEDNESDAY WITH READINGS FROM THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE SOUTHEAST. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... AS OF 255 PM EDT TUESDAY... HAVE A COUPLE DAYS MORE OF HUMID WEATHER BEFORE FRONT SWINGS ACROSS THURSDAY AND BRINGS A RETURN TO LOWER DEWPOINTS. UNTIL THEN...NO MAJOR CHANGES TO THE FORECAST. WEDNESDAY NIGHT A PIECE OF SHORTWAVE ENERGY ARRIVES ACROSS THE CENTRAL APPALACHIANS WHICH CREATES AN AREA OF SHOWERS AND STORMS...MAINLY AFFECTING THE WRN EDGE OF THE FORECAST AREA. THE BETTER PUSH OF THE FRONT ON THURSDAY COMBINED WITH BETTER UPPER SUPPORT SHOULD BRING SOME ENHANCED THREAT OF SHOWERS AND STORMS. TIMING OF THIS FRONT DOES VARY SOMEWHAT FROM THE MODELS BUT ENOUGH AGREEMENT TO HAVE HIGH CHANCE TO LIKLEY IN THE AREA THURSDAY. TIMING ALSO GIVES ISSUES TO SVR THREAT. ATTM...EXPECT A LINE OF SHRA/TSRA TO BE IN THE MTNS IN THE MORNING AND MOVING INTO THE PIEDMONT BY EARLY AFTERNOON. NOT SEEING A LOT OF HEATING AS CLOUDS WILL BE GENEROUSLY SPREAD. ONE AREA WITH THE BETTER INSOLATION COULD BE SOUTHSIDE VA/NW NC PIEDMONT. AT THIS TIME...THE STORM PREDICTION CENTER HAS A 5 PERCENT THREAT OF SVR WX MAINLY OVER THE PIEDMONT AND TIDEWATER AREAS OF VA/NC. THE FRONT WILL BE EAST OF THE AREA GOING INTO THURSDAY EVENING WITH LINGERING SHORTWAVE INDUCED SHOWERS ACROSS THE MTNS OVERNIGHT. THE MAIN SHORTWAVE SHIFTS EAST BY 12Z FRIDAY WITH DRIER AND COOLER AIR ARRIVING. HIGHS FRIDAY WILL RANGE FROM THE LOWER TO MID 60S WEST TO THE LOWER TO MID 70S EAST. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 PM EDT TUESDAY FOR THE LONG RANGE FORECAST...THE MODELS KEEP A TROUGH IN PLACE EARLY ON AND THEN GO MORE TOWARD A ZONAL TO RIDGE CONFIGURATION BY THE END OF THE PERIOD. WE SHOULD BE MAINLY DRY AS SFC HIGH BUILDS ACROSS THIS WEEKEND...SO WEEKEND HOLIDAY PLANS ARE LOOKING GOOD FOR OUTDOOR ACTIVITIES AT LEAST SATURDAY...AS THE LATEST ECMWF SHOWS ANOTHER WEAK SHORTWAVE PUSHING ACROSS BY SUNDAY AND MAY BRING SOME SHOWERS ACROSS THE MTN EMPIRE OF SW VA/INTO THE NC MTNS SUNDAY MORNING. THE FLOW SWINGS MORE TOWARD THE SOUTHEAST SUNDAY EVENING INTO EARLY NEXT WEEK WITH INCREASING HUMIDITY AND TEMPS. MODELS KEEPING MORE ACTIVE WEATHER ACROSS THE OHIO VALLEY AND WEST...ALTHOUGH A WESTERLY FLOW ALOFT CAN BRING STORMS WORKING EAST INTO THE MTNS. GIVEN WPC SOLUTION OF THE ECMWF ENSEMBLE WILL KEEP THE FORECAST MORE ON THE LOW CHANCE SIDE...BUT IF THE 12Z ECMWF VERIFIES WE COULD BE GETTING SOAKED AGAIN MONDAY-WEDNESDAY. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 202 AM EDT WEDNESDAY... THE MAIN CONCERN THIS MORNING APPEARS TO BE FOG AROUND AREAS THAT HAD HEAVY RAINFALL RECENTLY. LATEST DATA SUGGESTS PATCHY FOG WITH SOME AREAS OF LOCALLY DENSE FOG. IFR TO LIFR FOG WILL BE POSSIBLE. THE EARLIER SHOWERS HAVE DISSIPATED. ONLY ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED THIS MORNING. A QUICK IMPROVEMENT TO CONDITIONS WEDNESDAY MORNING WITH THE ONSET OF HEATING AND DECENT MIXING BY MID OR LATE MORNING. THINK ALL SITES WILL BE VFR BY 15Z/11AM BUT WITH A BETTER SHOT AT AFTERNOON CONVECTION DEVELOPING ESPCLY WEST OF THE BLUE RIDGE BY 20Z/4PM. WITH POTENTIAL TO SEE A BAND OF SHRA/TSRA DEVELOP WESTERN SLOPES...INCLUDED A PREVAILING -TSRA THREAT AT BOTH KBLF/KLWB WEDNESDAY AFTERNOON WHILE LEAVING ELSW VFR W/OUT CONVECTION UNDER SCTD/BKN 5-6K FT CU FIELDS. THE REGION STAYS IN A WARM...MOIST AIRMASS THROUGH THURSDAY AHEAD OF A COLD FRONT THAT SHOULD PUSH THROUGH LATE IN THE DAY THURSDAY. THIS WILL BRING THE BEST COVERAGE OF SHOWERS WEDNESDAY NIGHT INTO THURSDAY ALONG WITH AREAS OF LATE NIGHT/EARLY MORNING FOG. HIGH PRESSURE AND BETTER FLYING CONDITIONS ARE EXPECTED ON FRIDAY AND THROUGH MUCH OF THE WEEKEND BEHIND THE FRONT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/JH/KK SHORT TERM...WP LONG TERM...WP AVIATION.../WFORAH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1252 PM CDT WED MAY 22 2013 .SHORT TERM...(TODAY AND FRIDAY) ISSUED AT 309 AM CDT WED MAY 22 2013 MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH TONIGHT... THEN POSSIBLE PATCHY FROST OVER CENTRAL WISCONSIN THURSDAY NIGHT. LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL LOW OVER THE NORTHERN PLAINS AND SHORTWAVE TROUGHS ROTATING AROUND THE UPPER LEVEL LOW. LATEST MOSAIC RADAR INDICATING SCATTERED SHOWERS EXTENDING FROM LAKE SUPERIOR INTO SOUTHWEST MINNESOTA AND ANOTHER AREA OF SHOWERS AND THUNDERSTORMS FROM WESTERN ILLINOIS INTO SOUTHERN LAKE MICHIGAN. THE 22.00Z GFS/NAM ARE IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL FLOW THROUGH FORECAST PERIOD. BOTH MODELS ARE IN DECENT AGREEMENT LIFTING SHORTWAVE TROUGH OVER MISSOURI AND EASTERN KANSAS INTO SOUTHERN WISCONSIN TODAY. THE 22.00Z GFS/NAM AND 22.03Z RAP ARE IN AGREEMENT IN INCREASING PV ADVECTION...QG FORCING AND VERTICAL MOTION OVER THE FORECAST AREA 12-18Z TODAY AND DEVELOP PRECIPITATION OVER MUCH OF THE FORECAST AREA BY 18Z TODAY. CONFIDENCE IS INCREASING THE FORECAST AREA WILL SEE PRECIPITATION DEVELOP OVER FORECAST AREA BY 18Z. THE DETERMINISTIC MODELS INDICATE 0-6KM MOST UNSTABLE CAPE 300-500 J/KG OVER SOUTHEASTERN HALF OF THE FORECAST AREA AFTER 15Z TODAY. WILL CONTINUE TO MENTION ISOLATED THUNDERSTORMS. THE 22.00Z GFS/NAM SUGGEST UPPER LEVEL LOW WEAKENS AND DRIFTS SLOWLY EAST INTO THE GREAT LAKES REGION...AS AN UPPER LEVEL TROUGH DIGS OVER EASTERN GREAT LAKES REGION TONIGHT. WITH SURFACE RIDGE BUILDING INTO SOUTHERN ONTARIO AND THE WESTERN GREAT LAKES REGION... CLOUDS AND PRECIPITATION WILL DIMINISH FROM NORTH TO SOUTH ACROSS FORECAST AREA AFTER 06Z THURSDAY. DRY NORTHEASTERLY FLOW ALOFT DEVELOPS OVER FORECAST AREA THURSDAY. THE 22.00Z GFS/NAM BUFKIT SOUNDINGS ARE INDICATING FORECAST AREA MIXING UP TO 825MB BY 21Z. THIS SHOULD ALLOW FOR DEWPOINTS TO FALL INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS MUCH OF THE FORECAST AREA THURSDAY AFTERNOON. NEXT CONCERN IS LOW TEMPERATURES AND PATCHY FROST FRIDAY MORNING... WITH THE COMBINATION OF SURFACE RIDGE CENTERED AND DRY AIRMASS OVER FORECAST AREA...TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE 30S ACROSS PORTIONS OF CENTRAL WISCONSIN. PATCHY FROST WILL BE POSSIBLE ACROSS THIS PART OF THE FORECAST AREA. .LONG TERM...(FRIDAY NIGHT INTO TUESDAY) ISSUED AT 309 AM CDT WED MAY 22 2013 MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH FORECAST PERIOD. THE 22.00Z GFS/ECMWF/GEM CONTINUE TO DIFFER ON TIMING OF SHORTWAVE TROUGHS OVER-TOPPING UPPER LEVEL RIDGE OVER THE CENTRAL UNITED STATES AND PLACEMENT OF THE SURFACE RIDGE OVER THE GREAT LAKES REGION. WITH THIS...CONFIDENCE IN FORECAST IS LOW AND WILL CONTINUE WITH CONSISTENCY OF PRECIPITATION CHANCES THROUGH FORECAST PERIOD. TEMPERATURES WILL CLIMB INTO THE 60S FOR THE MEMORIAL DAY WEEKEND AND BE IN THE 70S TUESDAY...AS THE DETERMINISTIC MODELS INDICATE WARMER AIR ALOFT TO FILTER INTO THE REGION BY 00Z TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1252 PM CDT WED MAY 22 2013 CLOSED LOW LOCATED OVER NORTHEAST IA WILL SLOWLY FILL IN AND MOVE EAST INTO LOWER MI BY MORNING. PLAN ON IFR/MVFR CLOUD COVER AND BAND OF SHRA NORTH OF THE LOW TO PERSIST INTO TONIGHT. THEN LOOK FOR FAIRLY RAPID IMPROVEMENT INTO VFR CATEGORY AROUND 07Z AT KRST AND AROUND 09Z AT KLSE AS DRIER AIR WORKS IN FROM THE NORTH. HIGH PRESSURE WILL PROVIDE CLEAR SKIES ON THURSDAY WITH NORTH/NORTHEAST WINDS IN THE 10-20KT RANGE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM.....DTJ LONG TERM......DTJ AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
645 AM CDT WED MAY 22 2013 .SHORT TERM...(TODAY AND FRIDAY) ISSUED AT 309 AM CDT WED MAY 22 2013 MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH TONIGHT... THEN POSSIBLE PATCHY FROST OVER CENTRAL WISCONSIN THURSDAY NIGHT. LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL LOW OVER THE NORTHERN PLAINS AND SHORTWAVE TROUGHS ROTATING AROUND THE UPPER LEVEL LOW. LATEST MOSAIC RADAR INDICATING SCATTERED SHOWERS EXTENDING FROM LAKE SUPERIOR INTO SOUTHWEST MINNESOTA AND ANOTHER AREA OF SHOWERS AND THUNDERSTORMS FROM WESTERN ILLINOIS INTO SOUTHERN LAKE MICHIGAN. THE 22.00Z GFS/NAM ARE IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL FLOW THROUGH FORECAST PERIOD. BOTH MODELS ARE IN DECENT AGREEMENT LIFTING SHORTWAVE TROUGH OVER MISSOURI AND EASTERN KANSAS INTO SOUTHERN WISCONSIN TODAY. THE 22.00Z GFS/NAM AND 22.03Z RAP ARE IN AGREEMENT IN INCREASING PV ADVECTION...QG FORCING AND VERTICAL MOTION OVER THE FORECAST AREA 12-18Z TODAY AND DEVELOP PRECIPITATION OVER MUCH OF THE FORECAST AREA BY 18Z TODAY. CONFIDENCE IS INCREASING THE FORECAST AREA WILL SEE PRECIPITATION DEVELOP OVER FORECAST AREA BY 18Z. THE DETERMINISTIC MODELS INDICATE 0-6KM MOST UNSTABLE CAPE 300-500 J/KG OVER SOUTHEASTERN HALF OF THE FORECAST AREA AFTER 15Z TODAY. WILL CONTINUE TO MENTION ISOLATED THUNDERSTORMS. THE 22.00Z GFS/NAM SUGGEST UPPER LEVEL LOW WEAKENS AND DRIFTS SLOWLY EAST INTO THE GREAT LAKES REGION...AS AN UPPER LEVEL TROUGH DIGS OVER EASTERN GREAT LAKES REGION TONIGHT. WITH SURFACE RIDGE BUILDING INTO SOUTHERN ONTARIO AND THE WESTERN GREAT LAKES REGION... CLOUDS AND PRECIPITATION WILL DIMINISH FROM NORTH TO SOUTH ACROSS FORECAST AREA AFTER 06Z THURSDAY. DRY NORTHEASTERLY FLOW ALOFT DEVELOPS OVER FORECAST AREA THURSDAY. THE 22.00Z GFS/NAM BUFKIT SOUNDINGS ARE INDICATING FORECAST AREA MIXING UP TO 825MB BY 21Z. THIS SHOULD ALLOW FOR DEWPOINTS TO FALL INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS MUCH OF THE FORECAST AREA THURSDAY AFTERNOON. NEXT CONCERN IS LOW TEMPERATURES AND PATCHY FROST FRIDAY MORNING... WITH THE COMBINATION OF SURFACE RIDGE CENTERED AND DRY AIRMASS OVER FORECAST AREA...TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE 30S ACROSS PORTIONS OF CENTRAL WISCONSIN. PATCHY FROST WILL BE POSSIBLE ACROSS THIS PART OF THE FORECAST AREA. .LONG TERM...(FRIDAY NIGHT INTO TUESDAY) ISSUED AT 309 AM CDT WED MAY 22 2013 MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH FORECAST PERIOD. THE 22.00Z GFS/ECMWF/GEM CONTINUE TO DIFFER ON TIMING OF SHORTWAVE TROUGHS OVER-TOPPING UPPER LEVEL RIDGE OVER THE CENTRAL UNITED STATES AND PLACEMENT OF THE SURFACE RIDGE OVER THE GREAT LAKES REGION. WITH THIS...CONFIDENCE IN FORECAST IS LOW AND WILL CONTINUE WITH CONSISTENCY OF PRECIPITATION CHANCES THROUGH FORECAST PERIOD. TEMPERATURES WILL CLIMB INTO THE 60S FOR THE MEMORIAL DAY WEEKEND AND BE IN THE 70S TUESDAY...AS THE DETERMINISTIC MODELS INDICATE WARMER AIR ALOFT TO FILTER INTO THE REGION BY 00Z TUESDAY. && .AVIATION...TODAY AND TONIGHT 644 AM CDT WED MAY 22 2013 CLOSED CIRCULATION TO PASS JUST SOUTH OF THE TAF LOCATIONS OVER THE NEXT 24 HOURS. BROAD AREA OF LIGHT SHOWERS IN THE DEFORMATION AREA ON THE NORTHERN/WESTERN PERIPHERY. BROAD WEAK LIFT AND AVAILABLE MOISTURE WILL KEEP SHOWERS GOING...IN AT LEAST HIT-AND- MISS FASHION...FOR THE BULK OF THE PERIOD. ALSO OF CONCERN ARE LOW CLOUDS. IFR IS NOT FAR AWAY AND EXPECT IT TO EXPAND BACK INTO OUR REGION...FIRST AT KRST...AND FINALLY AT KLSE. THE PERSISTANT LOW SYSTEM WILL FINALLY DEPART ON THURSDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM.....DTJ LONG TERM......DTJ AVIATION...MW
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
309 AM CDT WED MAY 22 2013 .SHORT TERM...(TODAY AND FRIDAY) ISSUED AT 309 AM CDT WED MAY 22 2013 MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH TONIGHT... THEN POSSIBLE PATCHY FROST OVER CENTRAL WISCONSIN THURSDAY NIGHT. LATEST WATER VAPOR SATELLITE IMAGERY SHOWING UPPER LEVEL LOW OVER THE NORTHERN PLAINS AND SHORTWAVE TROUGHS ROTATING AROUND THE UPPER LEVEL LOW. LATEST MOSAIC RADAR INDICATING SCATTERED SHOWERS EXTENDING FROM LAKE SUPERIOR INTO SOUTHWEST MINNESOTA AND ANOTHER AREA OF SHOWERS AND THUNDERSTORMS FROM WESTERN ILLINOIS INTO SOUTHERN LAKE MICHIGAN. THE 22.00Z GFS/NAM ARE IN GOOD AGREEMENT WITH OVERALL UPPER LEVEL FLOW THROUGH FORECAST PERIOD. BOTH MODELS ARE IN DECENT AGREEMENT LIFTING SHORTWAVE TROUGH OVER MISSOURI AND EASTERN KANSAS INTO SOUTHERN WISCONSIN TODAY. THE 22.00Z GFS/NAM AND 22.03Z RAP ARE IN AGREEMENT IN INCREASING PV ADVECTION...QG FORCING AND VERTICAL MOTION OVER THE FORECAST AREA 12-18Z TODAY AND DEVELOP PRECIPITATION OVER MUCH OF THE FORECAST AREA BY 18Z TODAY. CONFIDENCE IS INCREASING THE FORECAST AREA WILL SEE PRECIPITATION DEVELOP OVER FORECAST AREA BY 18Z. THE DETERMINISTIC MODELS INDICATE 0-6KM MOST UNSTABLE CAPE 300-500 J/KG OVER SOUTHEASTERN HALF OF THE FORECAST AREA AFTER 15Z TODAY. WILL CONTINUE TO MENTION ISOLATED THUNDERSTORMS. THE 22.00Z GFS/NAM SUGGEST UPPER LEVEL LOW WEAKENS AND DRIFTS SLOWLY EAST INTO THE GREAT LAKES REGION...AS AN UPPER LEVEL TROUGH DIGS OVER EASTERN GREAT LAKES REGION TONIGHT. WITH SURFACE RIDGE BUILDING INTO SOUTHERN ONTARIO AND THE WESTERN GREAT LAKES REGION... CLOUDS AND PRECIPITATION WILL DIMINISH FROM NORTH TO SOUTH ACROSS FORECAST AREA AFTER 06Z THURSDAY. DRY NORTHEASTERLY FLOW ALOFT DEVELOPS OVER FORECAST AREA THURSDAY. THE 22.00Z GFS/NAM BUFKIT SOUNDINGS ARE INDICATING FORECAST AREA MIXING UP TO 825MB BY 21Z. THIS SHOULD ALLOW FOR DEWPOINTS TO FALL INTO THE MIDDLE 20S TO MIDDLE 30S ACROSS MUCH OF THE FORECAST AREA THURSDAY AFTERNOON. NEXT CONCERN IS LOW TEMPERATURES AND PATCHY FROST FRIDAY MORNING... WITH THE COMBINATION OF SURFACE RIDGE CENTERED AND DRY AIRMASS OVER FORECAST AREA...TEMPERATURES ARE EXPECTED TO DROP INTO THE MIDDLE 30S ACROSS PORTIONS OF CENTRAL WISCONSIN. PATCHY FROST WILL BE POSSIBLE ACROSS THIS PART OF THE FORECAST AREA. .LONG TERM...(FRIDAY NIGHT INTO TUESDAY) ISSUED AT 309 AM CDT WED MAY 22 2013 MAIN FORECAST CONCERN ARE PRECIPITATION CHANCES THROUGH FORECAST PERIOD. THE 22.00Z GFS/ECMWF/GEM CONTINUE TO DIFFER ON TIMING OF SHORTWAVE TROUGHS OVER-TOPPING UPPER LEVEL RIDGE OVER THE CENTRAL UNITED STATES AND PLACEMENT OF THE SURFACE RIDGE OVER THE GREAT LAKES REGION. WITH THIS...CONFIDENCE IN FORECAST IS LOW AND WILL CONTINUE WITH CONSISTENCY OF PRECIPITATION CHANCES THROUGH FORECAST PERIOD. TEMPERATURES WILL CLIMB INTO THE 60S FOR THE MEMORIAL DAY WEEKEND AND BE IN THE 70S TUESDAY...AS THE DETERMINISTIC MODELS INDICATE WARMER AIR ALOFT TO FILTER INTO THE REGION BY 00Z TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1131 PM CDT TUE MAY 21 2013 THE MAIN FOCUS AT THE TAF SITES IS WITH THE POTENTIAL FOR MVFR TO IFR FLIGHT CONDITIONS AND RAIN SHOWERS AS A LOW PRESSURE SYSTEM MOVES THROUGH THE REGION. THIS LOW IS CURRENTLY TO THE NORTHWEST OF THE REGION BUT IS STARTING TO SINK TO THE SOUTHEAST. ALL OF THE MVFR TO IFR CEILINGS ARE CURRENTLY TO THE NORTH AND WEST OF THIS LOW AND ARE EXPECTED TO GET INTO THE REGION LATER WEDNESDAY MORNING. THE EXACT TIMING OF THAT IS IN DOUBT...BUT RST SHOULD SEE SOME IFR CEILINGS MOVE IN AROUND DAYBREAK WITH MVFR POSSIBLE INTO LSE AROUND THE SAME TIME. SOME SHOWERS ARE EXPECTED TO DEVELOP IN THE MORNING HOURS AS WELL AND LAST THROUGH MUCH OF THE DAY BEFORE DIMINISHING IN THE EVENING HOURS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM.....DTJ LONG TERM......DTJ AVIATION.......HALBACH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1059 PM MDT TUE MAY 21 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 325 PM MDT TUE MAY 21 2013 EXTENDED THE WIND ADVISORY UNTIL 6 PM MDT FOR MOST OF THE NEBRASKA PANHANDLE. AT 2 PM MDT WINDS WERE GUSTING TO 51 MPH AT SCOTTSBLUFF AND 44 MPH AT ALLIANCE. WINDS SHOULD BEGIN A SLOW DECREASE THE REST OF THIS AFTERNOON AND THEN DROP OFF MORE QUICKLY THIS EVENING. WINDS WILL SHIFT TO THE NORTHEAST OVER EASTERN AREAS TONIGHT AND THEN TURN TO THE SOUTHEAST WEDNESDAY. THIS WILL BEGIN TO ALLOW LOW LEVEL MOISTURE TO ADVECT WESTWARD WHICH MAY ALLOW FOR INCREASING CHANCES OF THUNDERSTORMS THROUGH THE WEEK. KEPT A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND ADJACENT PLAINS FOR WEDNESDAY AFTERNOON. MODEL SOUNDINGS SHOWING STEEP LAPSE RATES WITH LITTLE TO NO CONVECTIVE INHIBITION. INSTABILITY IS NOT ALL THAT GREAT SO MAINLY LOOKING AT SHOWERS WITH A FEW WEAK THUNDERSTORMS. MODELS DO SHOW AN ELEVATED WARM FRONT MOVE EAST ACROSS THE FORECAST AREA WEDNESDAY NIGHT. THERE MAY BE ENOUGH INSTABILITY AND LIFT TO KEEP ISOLATED SHOWERS AND WEAK THUNDERSTORMS PECULATING INTO THE NIGH-TIME WHILE SHIFTING EAST INTO WESTERN NEBRASKA. SOUTH TO SOUTHEAST WINDS SHOULD BEGIN TO RAMP UP WEDNESDAY NIGHT AND THURSDAY. MODELS HAVE BEEN TRENDING STRONGER WITH LOW LEVEL FLOW THURSDAY. NAM AND GFS BUFKIT SOUNDING AT LUSK SHOWING 50 KT WINDS A FEW THOUSAND FEET ABOVE GROUND LEVEL THURSDAY AFTERNOON. SOUNDINGS ALSO SHOWING A VERY STRONG LOW LEVEL INVERSION DUE IN PART TO THE MOIST LOW LEVEL FLOW. KEPT A CHANCE FOR THUNDERSTORMS MAINLY OVER THE MOUNTAINS THURSDAY. MOST LIKELY A FEW STORMS WILL DEVELOP OVER THE LARAMIE RANGE...BUT WITH SUCH A STRONG CAP IN PLACE...STORMS MAY HAVE A TOUGH TIME MOVING INTO LOWER ELEVATIONS. ALONG WITH THE INVERSION EXPECTING A LOT OF STRATUS THURSDAY. STRATUS SHOULD PUT A LID ON TEMPERATURES. FOLLOWED THE PREVIOUS FORECAST SHIFT IN LOWERING DAYTIME HIGHS FOR THURSDAY. ALSO WARMED THE LOW A BIT WEDNESDAY NIGHT AND THURSDAY NIGHT. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 325 PM MDT TUE MAY 21 2013 FIRST UPPER SHORTWAVE EJECTING FROM PAC NW UPPER LOW WILL MOVE ACROSS THE AREA FRIDAY MORNING. TIMING SUCH THAT THERE MAY BE A BIT OF CONVECTION OVER MAINLY THE PANHANDLE BUT IF SFC BOUNDARY MOVES FAR ENOUGH EAST THE ACTIVITY WOULD BE EAST OF THE CWA. WILL KEEP SOME LOW POPS IN PLACE UNTIL BETTER CERTAINTY. SW FLOW ALOFT REMAIN IN PLACE OVER THE CWA OVER THE WEEKEND INTO EARLY NEXT WEEK SO SOME AFTERNOON AND EVENING CONVECTION WILL CONTINUE TO BE A POSSIBILITY...THOUGH TIMING WILL BE DIFFICULT. ECMWF DEPICTING IT PRETTY MUCH DAILY WHILE GFS DRIER. WILL KEEP POPS WHERE IT LOOKS MORE FAVORABLE SUCH AS SUNDAY AND MONDAY. TEMPERATURES WILL BE ON THE WARM SIDE FOR MUCH OF THE PERIOD...GENERALLY A LITTLE ABOVE SEASONAL AVERAGES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING) ISSUED AT 1057 PM MDT TUE MAY 21 2013 LATEST SREF AND HRRR GUIDANCE SHOWING SOME WRAP AROUND LOW CLOUDS MAKING IT INTO KCDR AND KAIA OVERNIGHT. UPSTREAM OBSERVATIONS IN SOUTH DAKOTA REPORTING CEILINGS DOWN AROUND 1500 FEET...SO THEIR FORECAST SEEMS REASONABLE. WENT AHEAD AND LOWERED CEILINGS AT KCDR AND KAIA TONIGHT. VFR ELSEWHERE. && .FIRE WEATHER... ISSUED AT 325 PM MDT TUE MAY 21 2013 WINDS WILL DROP OFF QUICKLY THIS EVENING AND BECOME LIGHT. WINDS WILL REMAIN ON THE LIGHT SIDE MAINLY IN THE 10 TO 15 MPH RANGE WEDNESDAY BUT WILL BEGIN TO INCREASE WEDNESDAY NIGHT...WITH STRONG SOUTHEAST WINDS ALONG AND EAST OF THE LARAMIE RANGE FOR THURSDAY. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL MAINLY BE CONFINED TO THE MOUNTAINS WEDNESDAY AND THURSDAY AFTERNOON. WEATHER CONDITIONS WILL VARY GREATLY FROM WEST TO EAST OVER THE FORECAST AREA LATE THIS WEEK AND WEEKEND. RELATIVELY MOIST CONDITIONS WILL BE FOUND EAST OF THE LARAMIE RANGE UNDER SOUTH TO SOUTHEAST LOW LEVEL FLOW...WHILE WEST OF THE LARAMIE RANGE DRY SOUTHWEST FLOW WILL DOMINATE PRODUCING LOW HUMIDITY. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...LIEBL LONG TERM...RE AVIATION...CLAYCOMB FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
421 AM EDT FRI MAY 24 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 225 AM EDT FRI MAY 24 2013 STRONG AND COOL CANADIAN HIGH PRESSURE CENTERED OVER THE GREAT LAKES WILL BUILD ACROSS THE OHIO VALLEY THE NEXT FEW DAYS. THIS WILL BRING BELOW NORMAL TEMPERATURES BUT DRY WEATHER FOR INDIANA THROUGH SATURDAY NIGHT. AS THE HIGH BEGINS TO DRIFT EAST ON SUNDAY...A WARM FRONT WILL APPROACH INDIANA FROM THE SOUTHWEST...BRING MORE CLOUDS...WARMER TEMPERATURES AND SMALL CHANCES FOR RAIN ON SUNDAY AFTERNOON THROUGH MONDAY. TEMPERATURES WILL RETURN TO NEAR NORMAL MEMORIAL DAY AND ABOVE NORMAL BY MIDWEEK NEXT WEEK. THUNDERSTORM CHANCES WILL ALSO RETURN NEXT WEEK AS GULF MOISTURE SPREADS NORTH ACROSS THE OHIO VALLEY. && .NEAR TERM /TODAY/... ISSUED AT 225 AM EDT FRI MAY 24 2013 SURFACE ANALYSIS EARLY THIS MORNING SHOWS A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE NORTH WOODS OF WISCONSIN AND LAKE SUPERIOR. COOL NORTH FLOW WAS IN PLACE ACROSS INDIANA. IR PICTURES SHOWED STRATOCU EXITING THE AREA TO THE EAST. THE WESTERN 1/2 OF THE OF THE STATE HAD ALREADY BECOME CLEAR. MAIN FORECAST CHALLENGE TODAY WILL BE TEMPS. FORECAST SOUNDINGS AND TIME HEIGHTS REMAIN QUITE DRY. FORECAST SOUNDINGS SHOW CONVECTIVE TEMPS IN THE UPPER 70S...AND GIVEN OUR 850MB TEMPS AROUND 3-5 DEGREES AMID COLD AIR ADVECTION...WE WILL NOT GET THAT WARM. THUS MOSTLY SUNNY SKIES EXPECTED TODAY. BACK TO TEMPS...GIVEN OUR 850MB TEMPS AND THE COOL START AND ONGOING COLD AIR ADVECTION WILL TREND HIGHS AT OR BELOW MAVMOS. && .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 225 AM EDT FRI MAY 24 2013 MAIN FORECAST CHALLENGE DURING THIS PERIOD WILL BE POPS ON SUNDAY AND SUNDAY NIGHT. LITTLE CHANGE IS EXPECTED THROUGH SATURDAY NIGHT WITH THE ONGOING WEATHER. THE PREVIOUSLY MENTIONED LARGE ARE OF HIGH PRESSURE WILL REMAIN ACROSS THE GREAT LAKES AND INDIANA...CONTINUING TO DOMINATE TH REGIONS WEATHER...PROVIDING MOSTLY CLEAR...COOL NIGHTS AND MOSTLY SUNNY AND COOL DAYS. ECMWF AND GFS CONTINUE TO BUILD A STRONG RIDGE OVER THE PLAINS STATES ALOFT WITH NORTHWEST FLOW ON THE LEE SIDE OF THE RIDGE SPILLING INTO INDIANA AND THE OHIO VALLEY. BY SATURDAY...SOME WARM AIR ADVECTION BEGINS IN SOUTHWEST INDIANA...HOWEVER THE COLD AIR LOOKS TO REMAIN IN PLACE THROUGH THE DAY AS 850MB TEMPS LOOK TO HOLD NEAR 5C THROUGH THE DAY. THUS WITH A FEW MORE HIGH AND MID CLOUDS EXPECTED ON SATURDAY WILL TREND HIGHS CLOSE TO EXPECTED PERSISTENCE. GFS INDICATES A SHORT WAVE PUSHING THROUGH THE NORTHWEST FLOW ACROSS INDIANA ON SUNDAY AFTERNOON AS WARM AIR ADVECTION CONTINUES IN THE LOWER LEVELS. GULF MOISTURE REMAINS CUT OFF AND DEW POINTS LOOK TO REMAIN IN THE RELATIVELY DRY 40S. GFS 300K ISENTROPIC SURFACE SHOWS SOME LIFT ACROSS THE AREA ON LATE SUNDAY AFTERNOON AND INTO SUNDAY NIGHT AS SPECIFIC HUMIDITIES RISE TO NEAR 7G/KG. FORECAST SOUNDINGS AND TIME HEIGHTS HINT AT MORE MOISTURE AVAILABLE IN THE COLUMN HOWEVER. THUS CONFIDENCE IN ANY RAIN REMAINS LOW AND WILL CONTINUE TO CARRY A LOW CHC POP DURING THIS TIME PERIOD. AS FOR TEMPS WILL CONTINUE TO HOLD VALUES AT OR BELOW MAVMOS GIVEN THE ADDITIONAL CLOUD COVER EXPECTED ACROSS THE AREA...ALONG WITH THE LOW PRECIPITATION CHANCES. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 152 AM EDT THU MAY 23 2013 ENSEMBLES IN GOOD AGREEMENT WITH THE LONG WAVE FEATURES DURING THIS PERIOD. UPPER RIDGE CURRENTLY OVER THE PLAINS IS EXPECTED TO GRADUALLY SHIFT EAST INTO THE MIDWEST AND OHIO VALLEY BY THE MIDDLE OF NEXT WEEK. APPEARS THERE IS A POTENTIAL FOR EMBEDDED SHORT WAVE TROUGHS TO RIDE THROUGH THE RIDGE...AT LEAST ON MONDAY AND TUESDAY. WILL CONTINUE WITH CHANCE POPS AT THOSE TIMES. BY NEXT WEDNESDAY AND THURSDAY...ENSEMBLES SUGGEST THE UPPER RIDGE WILL BUILD MORE AGGRESSIVELY OVER THE AREA AS DEEP TROUGHING DEVELOPS OVER THE WEST COAST AND ROCKIES. THIS SHOULD HELP TO CAP OFF PRECIPITATION CHANCES LATER NEXT WEEK...WITH THE ENSEMBLES SUGGESTING LITTLE THREAT FOR PRECIPITATION AFTER TUESDAY. WILL GO DRY FOR NEXT WEDNESDAY AND THURSDAY. && .AVIATION /DISCUSSION FOR THE 240900Z KIND TAF UPDATE/... ISSUED AT 421 AM EDT FRI MAY 24 2013 AREA OF MVFR CEILINGS AROUND 020 CONTINUE TO DRIFT SOUTH...AFFECTING THE KIND TERMINAL. EXTRAPOLATION OF THE BACK EDGE SUGGESTS THESE CEILINGS WILL SCATTER OUT AT KIND AROUND 241100Z. THERE WAS SOME POCKETS OF IFR CEILINGS AS WELL...BUT THESE SEEM TO HAVE DISSIPATED FOR THE MOST PART BASED ON UPSTREAM OBSERVATIONS. PREVIOUS DISCUSSION FOLLOWS. POCKETS OF MVFR CEILINGS TO PERSIST AT KBMG AND KIND FOR THE NEXT FEW HOURS...OTHERWISE VFR CONDITIONS EXPECTED. STRATOCU DECK CONTINUES TO ERODE FROM THE NORTHWEST...WITH KHUF AND KLAF NOW MAINLY CLEAR WITH PREDOMINANT CEILING UP TO 3500-4000FT AT BOTH KBMG AND KIND. RAP DATA INDICATING THAT A N/NE FLOW WILL KEEP AXIS OF DEEPER MOISTURE THROUGH THE BOUNDARY LAYER ALIGNED ACROSS THE REGION FOR THE NEXT 3-6 HOURS. CURRENT SATELLITE IMAGERY SUPPORTS THIS THINKING AS AREA OF LOWER CLOUDS DRIFTING SOUTH ACROSS NORTHERN INDIANA. WILL KEEP CLOUDS IN AT KBMG AND KIND FOR THE NEXT FEW HOURS WITH CLEARING THEREAFTER AS DRIER AIR ADVECTS INTO THE REGION WITH THE HIGH. NORTHERLY WINDS AT 10-15KTS CURRENTLY WILL DIMINISH TO 5-10KTS LATE. THE HIGH WILL EXPAND ACROSS THE OHIO VALLEY WITH QUIET WEATHER TODAY. PRESENCE OF THE DEPARTING LOW LEVEL THERMAL TROUGH INTO THE AFTERNOON MAY BE JUST ENOUGH TO GENERATE A FEW CU AT KIND. OTHERWISE...ANTICIPATE CLEAR SKIES AND NORTHERLY WINDS TO NEAR 10KTS ALL DAY. MAY START TO SEE SOME THIN CIRRUS DRIFT INTO THE REGION TONIGHT AS IT SPILLS OVER TOP OF THE UPPER RIDGE OVER THE CENTRAL PLAINS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA SHORT TERM...PUMA LONG TERM....JAS AVIATION...RYAN/JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
225 AM EDT FRI MAY 24 2013 .UPDATE... THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 225 AM EDT FRI MAY 24 2013 STRONG AND COOL CANADIAN HIGH PRESSURE CENTERED OVER THE GREAT LAKES WILL BUILD ACROSS THE OHIO VALLEY THE NEXT FEW DAYS. THIS WILL BRING BELOW NORMAL TEMPERATURES BUT DRY WEATHER FOR INDIANA THROUGH SATURDAY NIGHT. AS THE HIGH BEGINS TO DRIFT EAST ON SUNDAY...A WARM FRONT WILL APPROACH INDIANA FROM THE SOUTHWEST...BRING MORE CLOUDS...WARMER TEMPERATURES AND SMALL CHANCES FOR RAIN ON SUNDAY AFTERNOON THROUGH MONDAY. TEMPERATURES WILL RETURN TO NEAR NORMAL MEMORIAL DAY AND ABOVE NORMAL BY MIDWEEK NEXT WEEK. THUNDERSTORM CHANCES WILL ALSO RETURN NEXT WEEK AS GULF MOISTURE SPREADS NORTH ACROSS THE OHIO VALLEY. && .NEAR TERM /TODAY/... ISSUED AT 225 AM EDT FRI MAY 24 2013 SURFACE ANALYSIS EARLY THIS MORNING SHOWS A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE NORTH WOODS OF WISCONSIN AND LAKE SUPERIOR. COOL NORTH FLOW WAS IN PLACE ACROSS INDIANA. IR PICTURES SHOWED STRATOCU EXITING THE AREA TO THE EAST. THE WESTERN 1/2 OF THE OF THE STATE HAD ALREADY BECOME CLEAR. MAIN FORECAST CHALLENGE TODAY WILL BE TEMPS. FORECAST SOUNDINGS AND TIME HEIGHTS REMAIN QUITE DRY. FORECAST SOUNDINGS SHOW CONVECTIVE TEMPS IN THE UPPER 70S...AND GIVEN OUR 850MB TEMPS AROUND 3-5 DEGREES AMID COLD AIR ADVECTION...WE WILL NOT GET THAT WARM. THUS MOSTLY SUNNY SKIES EXPECTED TODAY. BACK TO TEMPS...GIVEN OUR 850MB TEMPS AND THE COOL START AND ONGOING COLD AIR ADVECTION WILL TREND HIGHS AT OR BELOW MAVMOS. && .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... ISSUED AT 225 AM EDT FRI MAY 24 2013 MAIN FORECAST CHALLENGE DURING THIS PERIOD WILL BE POPS ON SUNDAY AND SUNDAY NIGHT. LITTLE CHANGE IS EXPECTED THROUGH SATURDAY NIGHT WITH THE ONGOING WEATHER. THE PREVIOUSLY MENTIONED LARGE ARE OF HIGH PRESSURE WILL REMAIN ACROSS THE GREAT LAKES AND INDIANA...CONTINUING TO DOMINATE TH REGIONS WEATHER...PROVIDING MOSTLY CLEAR...COOL NIGHTS AND MOSTLY SUNNY AND COOL DAYS. ECMWF AND GFS CONTINUE TO BUILD A STRONG RIDGE OVER THE PLAINS STATES ALOFT WITH NORTHWEST FLOW ON THE LEE SIDE OF THE RIDGE SPILLING INTO INDIANA AND THE OHIO VALLEY. BY SATURDAY...SOME WARM AIR ADVECTION BEGINS IN SOUTHWEST INDIANA...HOWEVER THE COLD AIR LOOKS TO REMAIN IN PLACE THROUGH THE DAY AS 850MB TEMPS LOOK TO HOLD NEAR 5C THROUGH THE DAY. THUS WITH A FEW MORE HIGH AND MID CLOUDS EXPECTED ON SATURDAY WILL TREND HIGHS CLOSE TO EXPECTED PERSISTENCE. GFS INDICATES A SHORT WAVE PUSHING THROUGH THE NORTHWEST FLOW ACROSS INDIANA ON SUNDAY AFTERNOON AS WARM AIR ADVECTION CONTINUES IN THE LOWER LEVELS. GULF MOISTURE REMAINS CUT OFF AND DEW POINTS LOOK TO REMAIN IN THE RELATIVELY DRY 40S. GFS 300K ISENTROPIC SURFACE SHOWS SOME LIFT ACROSS THE AREA ON LATE SUNDAY AFTERNOON AND INTO SUNDAY NIGHT AS SPECIFIC HUMIDITIES RISE TO NEAR 7G/KG. FORECAST SOUNDINGS AND TIME HEIGHTS HINT AT MORE MOISTURE AVAILABLE IN THE COLUMN HOWEVER. THUS CONFIDENCE IN ANY RAIN REMAINS LOW AND WILL CONTINUE TO CARRY A LOW CHC POP DURING THIS TIME PERIOD. AS FOR TEMPS WILL CONTINUE TO HOLD VALUES AT OR BELOW MAVMOS GIVEN THE ADDITIONAL CLOUD COVER EXPECTED ACROSS THE AREA...ALONG WITH THE LOW PRECIPITATION CHANCES. && .LONG TERM /MONDAY THROUGH THURSDAY/... ISSUED AT 152 AM EDT THU MAY 23 2013 ENSEMBLES IN GOOD AGREEMENT WITH THE LONG WAVE FEATURES DURING THIS PERIOD. UPPER RIDGE CURRENTLY OVER THE PLAINS IS EXPECTED TO GRADUALLY SHIFT EAST INTO THE MIDWEST AND OHIO VALLEY BY THE MIDDLE OF NEXT WEEK. APPEARS THERE IS A POTENTIAL FOR EMBEDDED SHORT WAVE TROUGHS TO RIDE THROUGH THE RIDGE...AT LEAST ON MONDAY AND TUESDAY. WILL CONTINUE WITH CHANCE POPS AT THOSE TIMES. BY NEXT WEDNESDAY AND THURSDAY...ENSEMBLES SUGGEST THE UPPER RIDGE WILL BUILD MORE AGGRESSIVELY OVER THE AREA AS DEEP TROUGHING DEVELOPS OVER THE WEST COAST AND ROCKIES. THIS SHOULD HELP TO CAP OFF PRECIPITATION CHANCES LATER NEXT WEEK...WITH THE ENSEMBLES SUGGESTING LITTLE THREAT FOR PRECIPITATION AFTER TUESDAY. WILL GO DRY FOR NEXT WEDNESDAY AND THURSDAY. && .AVIATION /DISCUSSION FOR 240600Z TAF ISSUANCE/... ISSUED AT 1231 AM EDT FRI MAY 24 2013 POCKETS OF MVFR CEILINGS TO PERSIST AT KBMG AND KIND FOR THE NEXT FEW HOURS...OTHERWISE VFR CONDITIONS EXPECTED. STRATOCU DECK CONTINUES TO ERODE FROM THE NORTHWEST...WITH KHUF AND KLAF NOW MAINLY CLEAR WITH PREDOMINANT CEILING UP TO 3500-4000FT AT BOTH KBMG AND KIND. RAP DATA INDICATING THAT A N/NE FLOW WILL KEEP AXIS OF DEEPER MOISTURE THROUGH THE BOUNDARY LAYER ALIGNED ACROSS THE REGION FOR THE NEXT 3-6 HOURS. CURRENT SATELLITE IMAGERY SUPPORTS THIS THINKING AS AREA OF LOWER CLOUDS DRIFTING SOUTH ACROSS NORTHERN INDIANA. WILL KEEP CLOUDS IN AT KBMG AND KIND FOR THE NEXT FEW HOURS WITH CLEARING THEREAFTER AS DRIER AIR ADVECTS INTO THE REGION WITH THE HIGH. NORTHERLY WINDS AT 10-15KTS CURRENTLY WILL DIMINISH TO 5-10KTS LATE. THE HIGH WILL EXPAND ACROSS THE OHIO VALLEY WITH QUIET WEATHER TODAY. PRESENCE OF THE DEPARTING LOW LEVEL THERMAL TROUGH INTO THE AFTERNOON MAY BE JUST ENOUGH TO GENERATE A FEW CU AT KIND. OTHERWISE...ANTICIPATE CLEAR SKIES AND NORTHERLY WINDS TO NEAR 10KTS ALL DAY. MAY START TO SEE SOME THIN CIRRUS DRIFT INTO THE REGION TONIGHT AS IT SPILLS OVER TOP OF THE UPPER RIDGE OVER THE CENTRAL PLAINS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...PUMA NEAR TERM...PUMA SHORT TERM...PUMA LONG TERM....JAS AVIATION...RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1231 AM EDT FRI MAY 24 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 300 PM EDT THU MAY 23 2013 UPPER TROUGH ACROSS THE LOWER GREAT LAKES WILL MOVE SOUTHEAST ACROSS THE APPALACHIANS ON FRIDAY AS COOL CANADIAN HIGH PRESSURE SETTLES ACROSS THE GREAT LAKES AND OHIO VALLEY. THIS WILL RESULT IN CLEARING TONIGHT WITH BELOW TEMPERATURES THROUGH THE MEMORIAL DAY WEEKEND. SHOWER CHANCES WILL RETURN BY SATURDAY. TEMPERATURES WILL RETURN TO NEAR NORMAL MEMORIAL DAY AND ABOVE NORMAL BY MIDWEEK NEXT WEEK. THUNDERSTORM CHANCES WILL ALSO RETURN NEXT WEEK AS GULF MOISTURE SPREADS NORTH ACROSS THE OHIO VALLEY. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 945 PM EDT THU MAY 23 2013 UPDATE... HUNG ONTO CLOUD COVER A FEW HOURS LONGER THAN ORIGINAL FORECAST...BUT ANTICIPATE CLEARING TO ACCELERATE AFTER MIDNIGHT AS HIGH PRESSURE MAKES PUSH INTO FORECAST AREA. THIS WILL RESULT IN SUBSTANTIAL RADIATIONAL COOLING AND TEMPS DIPPING INTO THE UPPER 30S/LOW 40S. CURRENTLY...TEMPS ACROSS THE AREA ARE IN THE UPPER 40S/LOW 50S. CURRENT RADAR MOSAIC IS SHOWING A FEW LIGHT RETURNS OVER THE NORTHEAST QUADRANT AS ORIGINALLY EXPECTED...BUT THESE SHOULD DISSIPATE WITHIN THE NEXT HOUR. PREVIOUS DISCUSSION... MAIN CHALLENGES TONIGHT WILL BE TIMING OF END OF SHOWERS...CLEARING AND FINALLY TEMPERATURES AS AN UPPER LOW DROPS SOUTHEAST ACROSS THE LOWER GREAT LAKES AND COOL CANADIAN HIGH SURFACE BUILDS IN BEHIND A COLD FRONT. MODELS IN GOOD AGREEMENT ON DROPPING AN UPPER TROUGH...ACROSS THE WESTERN GREAT LAKES THIS AFTERNOON...TO LAKE ERIE BY FRIDAY MORNING. IN ADDITION...COOL CANADIAN HIGH PRESSURE WILL BUILD IN BEHIND A COLD FRONT THAT WAS PRESENTLY NEAR AN IND-HUF LINE. THIS WILL ALLOW CLEARING FROM NORTHWEST TO SOUTHEAST AS WELL AS AN END TO THE SHOWERS. THE SHOWERS SHOULD ONLY HANG AROUND TIL DARK ACROSS OUR EASTERN COUNTIES...SO PULLED SLIGHT CHANCE SHOWER POPS AFTER 02Z. LEANED TOWARD THE COLDER 12Z NAM MOS WHICH WAS BRINGING OVERNIGHT LOWS IN THE UPPER 30S ACROSS OUR NORTHWEST OVERNIGHT AND 40S ELSEWHERE. NORTHWEST WINDS WILL DROP TO BELOW 10 KNOTS AT DARK AS WELL. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... ISSUED AT 300 PM EDT THU MAY 23 2013 MAIN FOCUS TO THE SHORT TERM WILL BE ON POPS FOR THE MEMORIAL DAY WEEKEND WITH SO MANY OUTDOOR ACTIVITIES ON TAP. MODELS IN GOOD AGREEMENT ON COOL CANADIAN HIGH PRESSURE...KEEPING TEMPERATURES BELOW NORMAL THROUGH THE WEEKEND AS UPPER RIDGE CAMPS OUT ACROSS THE PLAINS. MODEL TIME SECTIONS SUGGEST CLEAR SKIES FRIDAY AND FRIDAY NIGHT WITH A DRY COLUMN AND HIGH PRESSURE IN PLACE. HOWEVER...MODELS IN AGREEMENT ON BRINGING QPF TO ALL OR PARTS OF CENTRAL INDIANA SATURDAY THROUGH SUNDAY AS UPPER WAVES TOP THE CENTRAL RIDGE AND DROP SOUTHEAST ACROSS CENTRAL INDIANA. IN ADDITION...305K ISENTROPIC LIFT WILL BE PLACE WITH INCREASING MOISTURE. THUS...WILL ADD SMALL POPS SATURDAY AND SATURDAY NIGHT ACROSS ALL BUT NORTHEASTERN PARTS OF THE FORECAST AREA AND RAISE POPS SLIGHTLY ON SUNDAY WITH GENERALLY CHANCE POPS WEST OF INTERSTATES 69 AND 65 AND SLIGHT CHANCE POPS EAST. GULF MOISTURE DOES NOT START INCREASING UNTIL EARLY NEXT WEEK...AND MODEL TIME SECTIONS ALSO REVEAL DRY AIR BELOW 850 MILLIBARS. SO...AM COMFORTABLE WITH THE LOWER ALLBLEND POPS. WOULD NOT RULE OUT THUNDER SUNDAY...BUT BEST INSTABILITY WILL BE WEST OF CENTRAL INDIANA. ALLBLEND TEMPERATURES RESEMBLE THE CLOSE MOS AND LOOK REASONABLE WITH THE COOL CANADIAN AIR POISED TO HANG AROUND. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... ISSUED AT 152 AM EDT THU MAY 23 2013 MODELS ARE SIMILAR ENOUGH FOR THE MOST PART THAT THE ALL BLEND INITIALIZATION WAS USED FOR MOST ITEMS. A WARM FRONT WILL REMAIN IN THE NEIGHBORHOOD EARLY IN THE EXTENDED...WHICH WILL ALLOW SOME SHOWERS AND THUNDERSTORMS TO DEVELOP. LOCATION OF FRONT AND TIMING OF ITS MOVING NORTHEAST REMAINS SOMEWHAT UNCERTAIN...SO RELUCTANTLY KEPT LOW POPS IN SUNDAY NIGHT INTO WEDNESDAY /EVEN THOUGH IT LIKELY WILL NOT RAIN EACH PERIOD/. RIDGING WILL THEN BUILD IN FOR THE END OF THE PERIOD. TEMPERATURES WILL WARM THROUGH THE PERIOD AS THE FRONT LIFTS NORTHEAST AND UPPER RIDGING BUILDS IN. && .AVIATION /DISCUSSION FOR 240600Z TAF ISSUANCE/... ISSUED AT 1231 AM EDT FRI MAY 24 2013 POCKETS OF MVFR CEILINGS TO PERSIST AT KBMG AND KIND FOR THE NEXT FEW HOURS...OTHERWISE VFR CONDITIONS EXPECTED. STRATOCU DECK CONTINUES TO ERODE FROM THE NORTHWEST...WITH KHUF AND KLAF NOW MAINLY CLEAR WITH PREDOMINANT CEILING UP TO 3500-4000FT AT BOTH KBMG AND KIND. RAP DATA INDICATING THAT A N/NE FLOW WILL KEEP AXIS OF DEEPER MOISTURE THROUGH THE BOUNDARY LAYER ALIGNED ACROSS THE REGION FOR THE NEXT 3-6 HOURS. CURRENT SATELLITE IMAGERY SUPPORTS THIS THINKING AS AREA OF LOWER CLOUDS DRIFTING SOUTH ACROSS NORTHERN INDIANA. WILL KEEP CLOUDS IN AT KBMG AND KIND FOR THE NEXT FEW HOURS WITH CLEARING THEREAFTER AS DRIER AIR ADVECTS INTO THE REGION WITH THE HIGH. NORTHERLY WINDS AT 10-15KTS CURRENTLY WILL DIMINISH TO 5-10KTS LATE. THE HIGH WILL EXPAND ACROSS THE OHIO VALLEY WITH QUIET WEATHER TODAY. PRESENCE OF THE DEPARTING LOW LEVEL THERMAL TROUGH INTO THE AFTERNOON MAY BE JUST ENOUGH TO GENERATE A FEW CU AT KIND. OTHERWISE...ANTICIPATE CLEAR SKIES AND NORTHERLY WINDS TO NEAR 10KTS ALL DAY. MAY START TO SEE SOME THIN CIRRUS DRIFT INTO THE REGION TONIGHT AS IT SPILLS OVER TOP OF THE UPPER RIDGE OVER THE CENTRAL PLAINS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/TDUD SHORT TERM...MK LONG TERM....50 AVIATION...RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
347 AM CDT FRI MAY 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 347 AM CDT FRI MAY 24 2013 00Z 500MB RAOBS INDICATE RISING HEIGHTS OVER THE CENTRAL CONUS WITH UPPER TROFS FLANKING A DEVELOPING RIDGE. THE RIDGE AT 700MB WAS OVER EASTERN KANSAS...WHILE AT 850MB DEWPOINTS RANGED FROM AROUND 3C AT KTOP AND KOUN TO AROUND 12 AT KDDC...KAMA...AND KFWD. WESTERN KANSAS RADARS AND OBSERVATIONS INDICATING SOME ISOLATED MID LEVEL CONVECTION WITH A WEAKENING CONVECTIVE CLUSTER OVER EASTERN COLORADO. ISENTROPIC LIFT INCREASES AND LOWERS TO AROUND 850MB TODAY AS THE 700MB RIDGE SHIFTS TO THE MISSOURI BORDER. LOW/MID LEVELS SLOWLY SATURATE...AND THERE MAY BE ENOUGH LIFT FOR ISOLATED TO SCATTERED ELEVATED STORMS BY SUNRISE AND CONTINUING THROUGH MUCH OF THE DAY. CHANCES SHOULD BE LIMITED TO THE WESTERN PORTIONS OF THE COUNTY WARNING AREA WITH THE MID LEVEL RIDGE STILL IN PLACE. SOME WEAKENING IN THE WAA OCCURS IN THE AFTERNOON AND COULD LEAD TO A DOWNWARD TREND...BUT A STRONGER LOW LEVEL JET IN AN INCREASINGLY MOIST TROPOSPHERE SUGGESTS SOME CHANCE FOR CONVECTION INCREASING AND SPREADING ACROSS KANSAS TONIGHT. THERE IS NOT MUCH OF A FOCUSING MECHANISM TO POINT TO ANY PARTICULAR LOCATIONS IN THE REGION FOR BETTER PRECIP CHANCES...BUT KEPT LARGEST CHANCES IN THE NORTH AND WEST WHERE SLIGHTLY BETTER MOISTURE ADVECTION AND PRECIPITABLE WATER SHOULD RESIDE. SOUTHEAST WINDS WILL INCREASE MORE THAN RECENT DAYS BY LATE THIS MORNING AS LEE LOW PRESSURE DEEPENS...WITH THE BETTER MIXING AND MODEST LOW LEVEL WAA RESULTING IN SLIGHTLY WARMER HIGHS. LOWS TONIGHT WILL BE SEVERAL DEGREES WARMER IN THE MORE MOIST AND INSULATED AIRMASS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 347 AM CDT FRI MAY 24 2013 THE WEEKEND PATTERN WILL BE CHARACTERIZED BY TROUGHS IN THE WEST AND EAST WITH A RIDGE OVER THE CENTRAL PLAINS THIS PATTERN REMAINS INTO MONDAY BEFORE THE RIDGE MOVES OFF TO THE EAST BY WEDNESDAY. SEVERAL PIECES OF ENERGY WILL MOVE OUT OF THE WESTERN TROUGH FROM SATURDAY THROUGH NEXT WEDNESDAY....HOWEVER THE UPPER TROUGH WILL MOVE OUT INTO THE EASTERN ROCKIES BY FRIDAY. THIS WILL PROVIDE NUMEROUS CHANCES FOR THUNDERSTORMS THROUGH THE PERIOD. THE TIMING OF THE WAVES EMANATING OUT OF THE WESTERN TROUGH IS HARD TO CALL AT THIS TIME. ALSO ANY MESOSCALE BOUNDARIES LEFT OVER FROM DECAYING OVERNIGHT CONVECTION WILL PROVIDE A FOCUS FOR LATER DEVELOPMENT. MOISTURE WILL MOVE BACK INTO CENTRAL AND EASTERN KANSAS AS THE LOW LEVEL JET BECOMES SOUTH TO SOUTHWEST OVER CENTRAL AND EASTERN KANSAS. A THETA-E RIDGE WILL STRETCH ACROSS NORTH CENTRAL AND NORTHEAST KANSAS THROUGH MUCH OF THE NEXT WEEK. CONVECTION IS EXPECTED TO DEVELOP IN THE WESTERN HIGH PLAINS AND INTO CENTRAL AND EASTERN NEBRASKA SATURDAY NIGHT WITH ISENTROPIC LIFT OVER A FRONTAL BOUNDARY NEAR THE NEBRASKA BORDER. HIGHEST CHANCES WILL REMAIN FOCUSED NORTH. AGAIN ANY OLD OUTFLOW BOUNDARY ACROSS THE CWA COULD BE A FOCUS FOR AFTERNOON CONVECTION AS MCS/S MOVE ACROSS NEBRASKA AND NORTHERN KANSAS ON SUNDAY. INSTABILITY COULD BE AS HIGH AS 3000 J/KG TO 4800 J/KG MUCAPE ACROSS THE CWA. DEEP LAYER SHEAR AROUND 30 KTS SUNDAY AFTERNOON. MOISTURE TRANSPORT VECTORS INCREASE ACROSS CENTRAL KANSAS INTO SOUTHEAST NEBRASKA THROUGH THE DAY. PRECIPITABLE WATER VALUES INCREASE TO AROUND 1.5 INCHES. LOCALLY HEAVY RAINFALL IS POSSIBLE WITH ANY CONVECTION SUNDAY AND SUNDAY NIGHT. CONTINUED CHANCES FOR NOCTURNAL CONVECTION WILL CONTINUE THROUGH THE BULK OF THE WEEK WITH MORE WIDELY SCATTERED ACTIVITY IN THE AFTERNOON AND EVENING HOURS. IF THUNDERSTORMS CONTINUE TO MOVE OVER THE SAME AREAS DURING THE WEEK COULD SEE SOME FLOOD/FLASH FLOODING. HIGHS WILL BE IN THE 80S THROUGH THE MONDAY THROUGH THURSDAY PERIOD WITH LOWS IN THE 60S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1145 PM CDT THU MAY 23 2013 MODELS CONTINUE TO SHOW INCREASING MOISTURE ADVECTION UP THROUGH CENTRAL KS AS THE LOW LEVEL JET VEERS AROUND MORE TO THE SOUTH. LATEST SATELLITE SHOWS A BAND OF AC WITHIN THE AXIS OF MOISTURE ADVECTION. THEREFORE WILL CONTINUE WITH A MENTION OF VCSH AT MHK BY MID MORNING AS ISENTROPIC PROGS SHOW SOME LIFT WITH LOWERING COND PRES DEF DEVELOPING ACROSS NORTH CENTRAL KS. THINK TOP AND FOE WILL REMAIN MAINLY TO THE EAST OF THE BETTER MOISTURE ADVECTION. THE NAM HAS BACKED OFF ON THE LOW LEVEL SATURATION AND MVFR CIGS. WITH THE RUC SHOWING SOME CONSISTENCY IN KEEPING CIGS VFR...HAVE TAKEN OUT THE MENTION OF MVFR CIGS AT MHK. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...53 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1145 PM CDT THU MAY 23 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 341 PM CDT THU MAY 23 2013 ALTHOUGH THE SURFACE LOW THAT IMPACTED THE REGION THIS PAST WEEKEND HAS PROGRESSED EAST OF THE GREAT LAKES REGION...AN ASSOCIATED COLD FRONT STILL STRETCHED WESTWARD ACROSS NORTHERN MISSOURI AND INTO EASTERN NEBRASKA. ENOUGH MOISTURE AND LIFT WAS PRESENT NEAR THIS BOUNDARY TO KEEP MUCH OF NORTHEASTERN KANSAS UNDER CLOUD COVER THROUGH MUCH OF THE DAY TODAY. VISIBLE SATELLITE IMAGERY SHOWED SOME SCATTERING OUT WITH THE CLOUD COVER BY MID AFTERNOON...WHICH ALLOWED AFTERNOON TEMPERATURES TO REACH INTO THE UPPER 60S TO LOWER 70S. SURFACE HIGH PRESSURE OVER THE NORTHERN PLAINS HAS SPILLED SOUTHWARD INTO THE CENTRAL PLAINS TODAY AND WILL SHIFT EAST OF THE AREA TONIGHT INTO FRIDAY AS THE UPPER LEVEL RIDGE CONTINUES TO BUILD OVER THE CENTRAL AND SOUTHERN PLAINS. EXPECT ANOTHER COOLER NIGHT ACROSS THE CWA THIS EVENING AS OVERNIGHT LOWS LOOK TO DROP INTO THE UPPER 40S TO LOWER 50S. MODELS CONTINUE TO SHOW SEVERAL EMBEDDED SHORTWAVES DEVELOPING ALONG THE NORTHERN EXTENT OF THIS RIDGE OVER THE UPCOMING DAYS...THE FIRST LOOKING TO DEVELOP TONIGHT INTO FRIDAY ACROSS EASTERN COLORADO AND WESTERN KANSAS. THIS SHORTWAVE ALSO LOOKS TO COINCIDE WITH A FRONTAL BOUNDARY STRETCHING SOUTHWARD FROM A SURFACE LOW OVER MONTANA INTO WESTERN NEBRASKA AND WESTERN KANSAS. BETTER CHANCES FOR PRECIPITATION LOOK TO BE ACROSS THE WESTERN HALF OF KANSAS IN THE VICINITY OF THIS BOUNDARY AND SHORTWAVE. THERE IS STILL SOME UNCERTAINTY AMONGST THE MODELS REGARDING HOW MUCH MOISTURE AND LIFT WILL BE ABLE TO SPREAD EASTWARD INTO THE FORECAST AREA ON FRIDAY TO SUPPORT THE DEVELOPMENT OF SOME SCATTERED SHOWERS AND THUNDERSTORMS. DUE TO THIS UNCERTAINTY...HAVE CHANCE POPS PRIMARILY FOCUSED OVER NORTH CENTRAL AND CENTRAL KANSAS THROUGH THE DAY WITH A MOSTLY DRY FORECAST FOR FAR EASTERN KANSAS. COULD START SEEING ANY SCATTERED PRECIPITATION THAT DEVELOPS SHIFT INTO NORTHEASTERN KANSAS BY FRIDAY EVENING AS THE SHORTWAVE PIVOTS A BIT FURTHER EAST ALONG THE RIDGE. THE INCREASED CLOUD COVER ACROSS THE AREA ON FRIDAY WILL KEEP TEMPERATURES ON THE COOLER SIDE ONCE AGAIN...WITH AFTERNOON HIGHS LOOKING TO TOP OUT IN THE UPPER 60S TO LOWER 70S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 341 PM CDT THU MAY 23 2013 THE MID AND LONG TERM FORECAST PERIOD REMAINS RATHER UNCERTAIN REGARDING SPECIFIC DETAILS OF LOCATION AND TIMING OF THUNDERSTORM POTENTIAL...BUT CONFIDENT IN SOME OF THE GENERAL FEATURES AS WELL AS A TEMPERATURE PATTERN. THE UPPER LEVEL FLOW PATTERN THIS WEEKEND WILL ACTUALLY BE CHARACTERIZED BY A RATHER SHARP RIDGE AXIS CENTERED OVER EASTERN KANSAS WITH A LONG WAVE TROUGH FIRMLY IN PLACE OVER THE WESTERN CONUS. SEVERAL PIECES OF ENERGY WILL TRANSLATE OUT OF THE WESTERN TROUGH FROM SATURDAY THROUGH NEXT WEEK...PROVIDING NUMEROUS CHANCES FOR THUNDERSTORMS THROUGH THE PERIOD. THE PRIMARY CHALLENGE WITH THIS FORECAST SEEMS TO BE IN INTERPRETING WHICH OF THESE IMPULSES WILL BE STRONG ENOUGH TO OVERCOME A CAPPING INVERSION ACROSS EASTERN KANSAS...AS WELL AS ANY PERIODS DURING WHICH THE DEEP LAYER SHEAR MARKEDLY INCREASES COINCIDENT WITH THE SHORT WAVE TROUGH PASSAGE. OTHERWISE...TEMPERATURES ARE EXPECTED TO BE GENERALLY IN THE 80S FOR HIGHS AND 60S FOR LOWS THROUGH THE ENTIRE PERIOD...WITH CLOUD COVER LARGELY DEPENDENT UPON CONVECTIVE SYSTEMS...AND A RATHER MOIST LOW LEVEL AIRMASS IN PLACE. IN TERMS OF SPECIFICS...IT WOULD APPEAR THAT A SHORT WAVE TROUGH PASSAGE WILL WEAKEN THE UPPER RIDGE ENOUGH ON FRIDAY NIGHT TO SUPPORT AN MCS ACROSS NEBRASKA...AND PERHAPS EVEN INTO NORTHERN KANSAS. THE REMNANTS OF THIS MCS MAY IMPACT MAINLY NORTHEAST KANSAS ON SATURDAY MORNING...BUT PERHAPS MORE IMPORTANTLY ARE EXPECTED TO PLACE AN OUTFLOW BOUNDARY ACROSS THE FORECAST AREA BY AFTERNOON. THE EXACT LOCATION OF ANY OUTFLOW WILL FOCUS ANY THUNDERSTORM ACTIVITY INITIALLY TO THAT LOCATION AND REMAINS UNCERTAIN...BUT INSTABILITY WILL BE MAXIMIZED ALONG THE BOUNDARY WITH INHIBITION MINIMIZED AND EXPECT AT LEAST A FEW STORMS TO DEVELOP ALONG ANY REMNANT OUTFLOW IF IT DOES INDEED EXIST. THE DEEP LAYER SHEAR PROFILE IS NOT PARTICULARLY STRONG ALTHOUGH IT MAY SUPPORT AT LEAST SOME BRIEF STORM ORGANIZATION BEFORE COLD POOLS INTERACT. SATURDAY NIGHT CONVECTION MAY ALSO TRACK ALONG THIS BOUNDARY ACROSS THE AREA OUT OF CENTRAL NEBRASKA. WILL NEED TO MONITOR THIS ACTIVITY FOR LATE NIGHT WIND/HAIL POTENTIAL SHOULD IT ORGANIZE INTO AN MCS. UPPER RIDGING IS FORECAST TO BUILD BACK IN OVER CENTRAL KANSAS IN THE WAKE OF THIS ACTIVITY...WITH ANY SUNDAY AFTERNOON CONVECTIVE POTENTIAL DEPENDING UPON A CAP BREAK. INSTABILITY SHOULD STILL BE STRONG ON SUNDAY AND THE DEEP SHEAR PROFILE SHOULD BE A BIT MORE IMPRESSIVE THAN SATURDAY...AND COULD SEE SOME SEVERE WEATHER POTENTIAL LATE SUNDAY INTO SUNDAY NIGHT. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE THROUGH THIS PERIOD GIVEN MODERATE TO HIGH PWAT VALUES AND POTENTIAL FOR STORMS TO FOCUS REPEATEDLY OVER THE SAME GENERAL AREAS. BEYOND SUNDAY...THE UNCERTAINTY REGARDING SPECIFICS IS JUST TOO GREAT TO GET BOGGED DOWN IN ANY DETAILS. OPERATIONAL MODELS MAINTAIN THE BROAD SOUTHWESTERLY UPPER FLOW PATTERN BUT DIVERGE REGARDING THE EVOLUTION OF THE EJECTION DATE OF THE PRIMARY UPPER LOW ITSELF. WHENEVER THE HEART OF THIS SYSTEM DOES ENTER THE CENTRAL PLAINS... WOULD EXPECT A GREATER POTENTIAL OF SEVERE WEATHER WITH INCREASED DEEP LAYER SHEAR AND PERHAPS A MORE ORGANIZED FOCUS FOR DEVELOPMENT. HAVE MAINTAINED SEVERAL RATHER SMALL CHANCES FOR PRECIPITATION THROUGH THE LONG TERM PERIOD BUT THERE IS A CHANCE THAT MUCH OF THE AREA COULD BE DRY UNTIL THE MAIN TROUGH APPROACHES...IT ALL REALLY DEPENDS ON WHETHER CAP STRENGTH CAN OUTLAST WEAK SHORT WAVE TROUGH STRENGTH ON A DAY TO DAY BASIS. EVEN AFTER THE MAIN TROUGH CROSSES THE PLAINS...IT LOOKS LIKE THE WEATHER PATTERN WILL REMAIN ACTIVE WITH SOUTHWEST FLOW REMAINING IN PLACE AND A NEW LONG WAVE TROUGH SETTLING OVER THE WESTERN U.S. BARJENBRUCH && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1145 PM CDT THU MAY 23 2013 MODELS CONTINUE TO SHOW INCREASING MOISTURE ADVECTION UP THROUGH CENTRAL KS AS THE LOW LEVEL JET VEERS AROUND MORE TO THE SOUTH. LATEST SATELLITE SHOWS A BAND OF AC WITHIN THE AXIS OF MOISTURE ADVECTION. THEREFORE WILL CONTINUE WITH A MENTION OF VCSH AT MHK BY MID MORNING AS ISENTROPIC PROGS SHOW SOME LIFT WITH LOWERING COND PRES DEF DEVELOPING ACROSS NORTH CENTRAL KS. THINK TOP AND FOE WILL REMAIN MAINLY TO THE EAST OF THE BETTER MOISTURE ADVECTION. THE NAM HAS BACKED OFF ON THE LOW LEVEL SATURATION AND MVFR CIGS. WITH THE RUC SHOWING SOME CONSISTENCY IN KEEPING CIGS VFR...HAVE TAKEN OUT THE MENTION OF MVFR CIGS AT MHK. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HENNECKE LONG TERM...BARJENBRUCH AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
326 AM EDT FRI MAY 24 2013 .Short Term (Now - Saturday)... Issued at 325 AM EDT Fri May 24 2013 Surface cold front continues to plow on off to the southeast this morning. Rain showers have long ended across southern Indiana and central Kentucky, but plenty of low clouds remain in place across the region. Drier air is trying to work in from the west, but a persistent north to northeasterly PBL flow is allowing the low clouds to continue to flow southward this morning. In the near term, expect mostly cloudy conditions to remain in place, though our western sections will probably see a little more clearing due to the closer proximity to the drier air in place to our west. Temperatures will continue to fall with cold air advection place...and we expect readings to fall into the mid-upper 40s by sunrise. For today, high pressure will slowly build in from the northwest. Dry punch of air will continue to make headway into the Ohio Valley, so we should see a rapid decrease in clouds during the morning hours with mostly sunny skies expected today. Dewpoints will likely drop into the 30s this afternoon and with a good amount of mixing and cooler air aloft, we`re likely to see a bit of a temperature gradient across the region. Afternoon highs will likely only top out in the 61-66 degree range across the Bluegrass region of central Kentucky with 65 to 70 degree readings in the I-65 corridor and points west. Surface winds will be out of the N to NE and will slacken later in the afternoon and into the evening hours. For tonight, high pressure and light winds will be in place which should set up a good radiational cooling period. The question remains whether we`ll see the development of fog or a potential frost. From a climatological perspective, the threat of frost is fairly low here in KY/IN. For the most part, it looks like temperatures will probably remain warm enough that we`ll see mostly patchy fog develop. However, some of our eastern counties may get a touch of frost...especially in our typical cold spots. For this reason, we will issue a special weather statement this morning highlighting the potential frost threat in the typical colder spots in the eastern Bluegrass region. Lows tonight will likely be in the upper 30s in the east with lower 40s in the central and western sections. Quiet and warmer conditions are expected for Saturday as high pressure moves on off to the east. This should kick our surface winds around to the south and eventually the southwest. Temperatures should moderate a bit on Saturday with highs in the 65-70 degree range in the Bluegrass with 70 to 75 in the central and western sections of the forecast area. .Long Term (Saturday Night through Thursday)... Issued at 310 AM EDT Fri May 24 2013 A amplified yet slowly progressive 500mb pattern will feature deep troughs across New England and the Pacific Northwest late Saturday. Eventually, ridging over the western plains will expand towards the Lower Ohio Valley. This will enable temperatures to warm substantially beginning Monday. High temperatures may actually approach 90 towards the end of the next work week. Canadian high pressure ridge axis will lie right over the Great Lakes late Saturday, extending southward across the Commonwealth. Cool weather with low dewpoints will continue through Sunday, along with light winds. Despite the possibility of some increasing high cloudiness associated with a warm front to our southwest, lows early Sunday will fall well down into the lower to mid 50s. Quite a bit of uncertainty and disagreement exists between some of the long range guidance for the Sunday through Tuesday time frame. Overall, warmer more moist air will attempt to move northeast into the Lower Ohio Valley. However, a deep slow moving low over New England and persistent northwest flow aloft over the Commonwealth will retard the northeast progress of this boundary. It is likely during the first couple of days of next week that several convective clusters will develop across the midwest, aided by moisture advection and the presence of a nocturnal low level jet. These periodic thunderstorms may slide southeast, bringing at least a chance of difficult-to-time thunderstorms beginning Sunday afternoon and possibly continuing through Tuesday. Both the ECMWF and the GFS forecast the surface boundary to stretch early Sunday from northern Missouri southeast towards central Tennessee. The consistent ECMWF has been slower in bringing this boundary north across the Commonwealth than the GFS. However, by Tuesday afternoon, both of these models have this boundary as far north as southern Ohio. Will continue our forecast of at least a chance of thunderstorms Sunday afternoon through Tuesday, with an admittedly low confidence on attempting to time any areas of convection moving southeastward along this boundary. Highs on Sunday will likely remain in the 70s, warming to the lower to mid 80s by Tuesday. For Wednesday and Thursday, mid-summer like ridging will develop over the Tennessee Valley. Expect that these two days will stay dry with quite warm temperatures in the mid to upper 80s. && .Aviation (06Z TAF Issuance)... Issued at 115 AM EDT Fri May 24 2013 MVFR ceilings are expected to persist at the terminals through the overnight period. Previous thinking from earlier was for clouds to clear out in the 07-09Z time frame. However, latest trajectory data from the RAP and LMK local WRF model suggests that the low-level PBL will be more northerly to a little northeasterly overnight. IR satellite imagery suggests that this may be correct as cloud cover has not really eroded all that much to our north and more clouds up over northern Indiana are heading southward. Upstream observations show that ceilings are holding around 2kft AGL and we expect these conditions to continue through much of the overnight period. Feel that ceilings will eventually mix out and go back to VFR by around 24/11Z or so and then continue throughout the day. Surface winds for the next few hours will remain out of the NNW to N at 10-13kts with occasional gusts up to 15-18kts. Winds look to shift to the northeast during the daylight hours and then diminish near toward the end of the TAF period. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Short Term.......MJ Long Term........JSD Aviation.........MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
117 AM EDT FRI MAY 24 2013 ...Updated Aviation Discussion... .Forecast Update... Issued at 115 AM EDT Fri May 24 2013 Current forecast still pretty much on track. Will be make a few changes to the cloud grids as sky cover will likely remain mostly cloudy for a good portion of the night. Latest RAP and LMK WRF data showing more of a north to north-northeast low level PBL flow which should keep clouds in here a little longer than previously forecast. This will keep temperatures from dropping as fast as previously thought. So will also make some minor adjustments there as well. Update issued at 1210 AM EDT Fri May 24 2013 Radar and surface observations show that rain showers have been diminishing quite rapidly across the region as the secondary surface cold pushes southward through the region. Latest 11-3.9 micron satellite imagery shows deck of low clouds across the forecast area and extends back into central Indiana. Based on satellite imagery, back edge of clouds look to clear the Ohio River around 3AM EDT and then clear much of southern Kentucky by sunrise. Have updated the forecast based on those cloud trends and also have removed PoPs from most areas. Temperatures with the new airmass coming in are quite cool for mid-late May. Readings have cooled into the lower 50s across our far northern areas and have dropped into the mid-upper 50s across northern Kentucky. Based on the short-term consensus model runs, looks like min temperatures will cool into the lower 40s across southern Indiana with upper 40s across Kentucky by sunrise. Winds will remain out of the NNW to N at 10 to 15 mph. && .Short Term (Now - Friday Night)... Issued at 300 PM EDT Thu May 23 2013 A deep trough over the Great Lakes is currently pivoting, with the axis on track to pass over the forecast area this evening and tonight. At the surface, a cold front is dropping southeastward through central Indiana. This front is forecast to exit our southeast forecast area by about midnight tonight. Scattered showers are developing along and ahead of the front. This will continue across our area the rest of this afternoon and into the evening hours. Surface-based instability is rather weak and these showers are capped at or just above the freezing level. Could see an isolated thunderstorm, but chances are rather low. Activity will dissipate late this evening and clouds will slowly diminish from northwest to southeast overnight. Winds will become northwesterly with the frontal passage, then northerly by daybreak Friday. Dry and much cooler air will begin to work into the region from the northwest, with temperatures dropping into the middle and upper 40s tonight. Despite almost unlimited sun on Friday, temperatures will be rather cool, ranging from the middle 60s to around 70 degrees. High pressure will build directly overhead Friday night. Clear skies and light winds will provide for quite chilly conditions, with lows bottoming out in the upper 30s and lower 40s. Typically cooler valleys could drop into the middle 30s. .Long Term (Saturday through Thursday)... Issued at 310 PM EDT Thu May 23 2013 High confidence forecast for Saturday with a 1030mb surface high over Lake Michigan, and extending south into the Ohio Valley. Expect plenty of sunshine and below-normal temps. Given forecast soundings, low-level thicknesses, and typical behavior in NE low-level flow, believe that GFS MOS temps are too warm. Have leaned more toward the cooler NAM MOS, with highs ranging from the upper 60s over the Bluegrass to the mid 70s near Bowling Green. Confidence heads downhill quickly beginning on Saturday night thanks to NW flow aloft and divergent model solutions. There is consensus that a NW-SE oriented surface boundary will develop somewhere across the Ohio and/or Tennessee Valleys. However, the GFS leans more toward a warm front developing over the Ohio Valley and lifting north by Monday night, while the ECMWF has the front to our south initially and not lifting out of the Ohio Valley until Wed/Thu. With a shortwave ridge axis over the Plains, there is at least a decent chance that MCSs will develop west of the Mississippi and roll SE along the front. Confidence is limited by the difficulty in timing the development of these complexes, and determining whether they will hold together as they move into what will be a less favorable environment. Therefore we will generally advertise slight chance POPs, only bumping up to a 30 POP west of I-65 for Monday. Temp forecast will undercut the GFS MOS as we do not believe the warm front will lift northward that quickly. Will stay below normal through Monday. Upper ridging will build from the southern Plains beginning on Tuesday and continue through at least Thursday. Expect temps trending back above normal for late May, and will continue diurnal slight chance POPs. Greatest bust potential will be from southern Indiana into the Bluegrass, where the cooler and wetter pattern could persist an additional day or two if the warm front is slower to lift out. && .Aviation (06Z TAF Issuance)... Issued at 115 AM EDT Fri May 24 2013 MVFR ceilings are expected to persist at the terminals through the overnight period. Previous thinking from earlier was for clouds to clear out in the 07-09Z time frame. However, latest trajectory data from the RAP and LMK local WRF model suggests that the low-level PBL will be more northerly to a little northeasterly overnight. IR satellite imagery suggests that this may be correct as cloud cover has not really eroded all that much to our north and more clouds up over northern Indiana are heading southward. Upstream observations show that ceilings are holding around 2kft AGL and we expect these conditions to continue through much of the overnight period. Feel that ceilings will eventually mix out and go back to VFR by around 24/11Z or so and then continue throughout the day. Surface winds for the next few hours will remain out of the NNW to N at 10-13kts with occasional gusts up to 15-18kts. Winds look to shift to the northeast during the daylight hours and then diminish near toward the end of the TAF period. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........MJ Short Term.......MJP Long Term........RAS Aviation.........MJ
AREA FORECAST DISCUSSION
NWS GRAY ME
1218 AM EDT FRI MAY 24 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY CROSS THE REGION TONIGHT WILL STALL OFF THE COAST ON FRIDAY. LOW PRESSURE WILL DEVELOP ON THE FRONT SOUTH OF CAPE COD FRIDAY NIGHT AND SLOWLY MOVE NORTH THROUGH THE GULF OF MAINE THROUGH SUNDAY MORNING. LOW PRESSURE WILL CONTINUE NORTH THROUGH THE MARITIMES SUNDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST MONDAY AND WILL SHIFT OFFSHORE ON TUESDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST ON WEDNESDAY. && .NEAR TERM /UNTIL 9 AM THIS MORNING/... 1205 AM...JUST A QUICK UPDATE TO ADJUST POPS AND TEMPS A BIT OVERNIGHT...AND TO FOCUS ON BEST CH OF HEAVIER DOWNPOURS IN THE 06-13Z TIME FRAME AS 500 MB SH COMBINES WITH MID-LVL JET AND HIGH PWATS...APPROACHING 200% OF NORMAL COM TO TOGETHER TO PRODUCE A SURGE OF HEAVY RAINFALL...WHICH WILL DEVELOP AFTER MIDNIGHT AND LKLY AFFECT MORNING COMMUTE. 00Z NAM12 AND LATEST HRRR FOCUS THE BULK OF THE PRECIP CLOSER TO THE COAST...WHERE THE GROUND CAN HANDLE IT BETTER. HOWEVER...COULD CAUSE SOME LOCALIZED PROBLEMS...PONDING ON THE ROADS AND IN URBAN AREAS. UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS. RADAR CONTS TO SHOW AREAS OF SHOWERS AND ISOLD TSTMS OVER THE NRN MTNS WHERE WE HAVE ISSUED AN AREAL FLOOD ADVISORY. OVER SRN NH...THE ECHOES CONT TO WEAKEN AS THEY HEAD NORTH...DESPITE A PRECIPITABLE WATER LEVEL AXIS OF 1.6" OVER THE REGION. LATEST HRRR RUN CONTS TO SHOW PCPN STREAMING IN FROM THE SOUTH OVERNIGHT...ALONG AND AHEAD OF APPROACHING COLD FRONT. CATEGORICAL POPS WILL REMAIN IN THE GRIDS OVERNIGHT WITH PATCHY/AREAS OF FOG. EXPECT AROUND AN INCH OR SO OF RAINFALL OVER THE COASTAL AREAS WHICH REMAINS WELL BELOW FLASH FLOOD GUIDANCE. PREV DISC... COLD FRONT APPROACHING FROM THE WEST WILL MAKE FOR A WET AND BREEZY NIGHT ACROSS THE REGION. SCATTERED SHOWERS AND SOME THUNDERSTORMS WILL GRADUALLY CHANGE TO A WIDESPREAD RAIN OVERNIGHT AS THE FRONT SLOWLY CROSSES THE AREA. EXPECT THUNDERSTORM ACTIVITY TO BE MAINLY CONFINED TO NEW HAMPSHIRE LATE THIS AFTERNOON AND THIS EVENING AS MARINE LAYER PERSISTS ACROSS MOST OF MAINE. CAN`T RULE OUT A RUMBLE OF THUNDER OVERNIGHT BUT SHOULD BE ISOLATED AND HAVE NOT INCLUDED THIS IN THE FORECAST AFTER THIS EVENING. EXPECT OVERNIGHT LOWS TO BE UNIFORM ACROSS THE REGION WITH MOST AREAS DIPPING INTO THE MID 50S TO NEAR 60. && .SHORT TERM /9 AM THIS MORNING THROUGH 6 PM SATURDAY/... FRONT WILL STALL JUST OFF THE COAST ON FRIDAY WITH RAIN CONTINUING THROUGH THE DAY ACROSS THE FORECAST AREA. NOT EXPECTING TEMPERATURES TO MOVE MUCH FROM OVERNIGHT LOWS WITH MOST LOCATIONS ONLY REACHING THE UPPER 50S TO LOWER 60S. RAIN CONTINUES FRIDAY NIGHT AS LOW PRESSURE TRACKS NORTH ALONG THE FRONT. FOCUS WILL TURN TO AREA RIVERS IN NORTHERN ZONES WHERE STORM TOTALS COULD WILL FALL IN THE THE 2 TO 4 INCH RANGE BY LATE ON SUNDAY. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... CUTOFF AND SFC LOW WILL DRIFT SLOWLY NE THRU THE WEEKEND CONTINUING PRCP ACROSS THE FCST AREA WITH THE POTENTIAL FOR HEAVY RAINFALL. MODELS SHOWING MAX QPF ACROSS THE N/MT ZONES TO WRN NH ZONES. GFS MUCH HIGHER ON QPF...WITH OTHER MODELS PREFERRED. USED HPC QPF FOR A COMPROMISE. CUTOFF AND SFC LOWS MOVE NE OF THE AREA MONDAY WITH IMPROVING WX...BUT STILL COOL AIR AND CYCLONIC FLOW ALOFT ALONG WITH FAIRLY AMPLE RH COULD PRODUCE SOME CLOUDS AND PSBL -SHRA EVEN ON MONDAY. FOR NOW WILL GO WITH SLGT CHC. AN UPR LVL AND SFC RIDGE BUILD IN TUESDAY FINALLY BRINGING DRY WX WITH WARMING TEMPS. AN UPR LVL SHORT WAVE TROF SLIDES E THRU THE UPR LVL RIDGE LATE WEDNESDAY AND WEDNESDAY NGT...BRINGING ISOLD TO SCT SHRA TO THE REGION WEDNESDAY NGT AND THURSDAY. GENERALLY USED BLEND OF GFS40/NAM, MET/MAV & HPC QPF FOR DAYS 4 AND 5 THEN A BLEND OF GFS40, GMOS, MEX/ECE FOR THE REST OF THE LONG TERM FCST. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... SHORT TERM...IFR/LIFR CEILINGS/VSBY TONIGHT THROUGH FRIDAY. LONG TERM /SATURDAY THROUGH TUESDAY/...IFR/LIFR SATURDAY THRU MUCH OF SUNDAY...IMPROVING TO VFR WITH PSBL MVFR ON MONDAY THEN VFR TUESDAY. && .MARINE... SHORT TERM...SCA IN EFFECT THROUGH FRIDAY TONIGHT. LONG TERM /SATURDAY THROUGH TUESDAY/...NE WINDS AHEAD OF APPROACHING LOW AND SEAS LIKELY AT SCA LEVELS SATURDAY AND MAY NEED TO EXTEND THE SCA THRU THE DAY. WINDS LET UP AND BACK TO THE NW SLOWLY SATURDAY NGT THRU MONDAY...LIKELY DROPPING BELOW SCA LEVELS BY LATE SATURDAY NGT OR EARLY SUNDAY. SEAS WILL BE SLOWER TO DROP OFF. HIGH PRES PROVIDES RELATIVELY CALMER WINDS AND SEAS ON TUESDAY. && .FIRE WEATHER... NO PROBLEMS NOTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT SATURDAY FOR ANZ150>154. && $$ SYNOPSIS... NEAR TERM...CEMPA SHORT TERM... LONG TERM... AVIATION... MARINE... FIRE WEATHER... HYDROLOGY...
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
340 AM EDT FRI MAY 24 2013 .SHORT TERM...TODAY AND TONIGHT THE WEATHER UP FOR DISCUSSION IS THE PROSPECTS FOR OVERCAST SKIES TODAY AS AN OPAQUE BLANKET OF 030-035 FT STRATUS IS AGGRESSIVELY DIVING SOUTHWARD ACROSS LAKE HURON. TRAJECTORY OF CLOUD DECK IN ADDITION TO THE ORIENTATION OF THE WESTERN EDGE ALIGNS WELL WITH THE AXIS OF MAXIMUM 925-850MB COLD AIR ADVECTION AND THE DEPRESSION OF THE LONGWAVE TROUGH AXIS. NWP DATA IS VIRTUALLY VOID OF CLOUD...A RESULT OF INADEQUATE VERTICAL RESOLUTION WITHIN THE MODELS. WHILE THE CLOUD IS COMPLETELY OPAQUE IT IS UNDOUBTEDLY A SHALLOW LAYER OF MOISTURE THAT IS LIKELY TRAPPED WITHIN THE BASE OF THE INVERSION AT/AROUND 900-890MB. RUC SOUNDINGS SHOW SATURATION AT THIS ZONE...BUT THE SOUNDING STRUCTURE ITSELF DOES NOT INSPIRE MUCH CONFIDENCE AS IT IS THE WRONG PROFILE. GIVEN THE TRUE NORTHERLY TRAJECTORY...HAVE DECIDED TO INTRODUCE OVERCAST CONDITIONS FOR MUCH OF THE CWA THROUGH THE MORNING HOURS. IT WILL BE DIFFICULT TO PINPOINT ANY WEST EDGE OF THE CLOUDS GIVEN DEGREE OF DRY AIR IMMEDIATELY TO THE WEST. PATTERN RECOGNITION SUGGESTS ENTRAINMENT AT THE EDGE SHOULD AID DIURNAL MIXING TO FORCE STRATUS TO GO BROKEN BY LATE MORNING...EVENTUALLY CLEARING OUT FOR THE AFTERNOON. LOWERED MAX TEMPERATURES FOR MANY AREAS DUE TO THE CLOUD AND STEADY COLD AIR ADVECTION. EXPECT TEMPERATURES TO EVENTUALLY REACH 60-61 DEGREES ACROSS THE SOUTH AND SAGINAW VALLEY VERY LATE IN THE DAY. OTHERWISE TEMPERATURES ARE GOING TO STRUGGLE TO REACH THE LOWER 50S IN THE THUMB. FOR TONIGHT...THE COMPACT VORT OVER NORTHERN MANITOBA WILL GET SQUEEZED WITH A ROGUE VORTICITY STREAMER OFF OF THE PACNW ANOMALY MERGING OVER THE WESTERN GREAT LAKES. THIS WILL OCCUR DOWN THE FRONT EDGE OF THE CENTRAL CONUS RIDGE...ALLOWING FOR A VERY HEALTHY AGEOSTROPHIC RESPONSE AND STRIPE OF FRONTOGENESIS VERY LATE. ANY SIGNIFICANT TEMPERATURE GRADIENT WILL RESIDE WELL WEST OF LOWER MICHIGAN WHICH IS WHERE THE PRECIPITATION RESPONSE WILL OCCUR. REGARDLESS...INCREASING CLOUDS LATE WILL ESTABLISH A FLOOR ON MINIMUM TEMPERATURES TONIGHT. && .LONG TERM...SATURDAY THROUGH THURSDAY THE OVERALL PATTERN ACROSS NORTH AMERICA THIS WEEKEND WILL FEATURE A QUASI OMEGA BLOCK. SHORT WAVE ENERGY NOW SHOWN ROTATING INTO NRN MANITOBA IS FORECAST TO TRACK ACROSS THE ERN GREAT LAKES AND MID ATLANTIC EARLY SATURDAY...LEADING TO DEEPENING OF AN UPPER LOW ROTATING ACROSS NEW ENGLAND. LOWER MI WILL BE LOCATED BETWEEN THIS SYSTEM AND AMPLIFYING MID LEVEL RIDGING ACROSS THE NRN PLAINS/UPPER MS VALLEY. THIS WILL PLACE THE FORECAST AREA WITHIN A STRONGLY CONFLUENT UPPER FLOW WITH PERSISTENT HIGH PRESSURE AT THE SURFACE. THE RESIDENT AIRMASS ACROSS THE GREAT LAKES WILL BE COOL AND VERY DRY. TEMPS ON SATURDAY SHOULD ONLY RISE TO THE LOW 60S OVER MUCH OF THE FORECAST AREA WITH 850MB TEMPS HOVERING AROUND +2C. THE AIRMASS WILL MODERATE DURING THE COURSE OF THE WEEKEND...WITH HIGHS EXPECTED TO BE AROUND 70 BY MEMORIAL DAY. GIVEN THE DRY AIRMASS AND LIGHT WINDS...NIGHTTIME LOWS WILL BE QUITE CHILLY THIS WEEKEND /30S AND 40S/. A SEASONALLY STRONG 140+ KNOT UPPER JET IS FORECAST DIVE INTO THE PACIFIC NORTHWEST EARLY NEXT WEEK...LEADING TO LONG WAVE TROUGH AMPLIFICATION ACROSS THE WRN US AND A BUILDING SUBTROPICAL RIDGE ACROSS THE SERN US. THIS WILL ALLOW THE MID LEVEL RIDGE TO BECOME MORE PROGRESSIVE AND PASS EAST OF LOWER MI TOWARD MIDWEEK...ALLOWING A SFC WARM FRONT TO LIFT ACROSS THE REGION FROM THE SOUTHWEST. THIS WARM FRONT WILL ADVECT A WARM...MOIST AND UNSTABLE AIRMASS INTO THE FORECAST AREA. THE GFS CONTINUES TO BRING THIS WARM FRONT THROUGH FASTER THAN THE OTHER MODEL SOLUTIONS /SUGGESTING CONVECTION AS EARLY AS MON NIGHT/. THE GFS HAS SOME OBVIOUS CONVECTIVE FEEDBACK ISSUES DUE TO POTENTIAL MCS DEVELOPMENT OVER THE PLAINS. THE GFS IS ALSO LESS AMPLIFIED WITH THE LONG WAVE TROUGH OVER THE WRN US. GIVEN THE STRENGTH OF THE POLAR JET AND POTENTIAL PHASING WITH THE SUBTROPICAL JET...THE MORE AMPLIFIED ECMWF REMAINS THE PREFERRED SOLUTION. THIS SUGGESTS THE BETTER CHANCES FOR CONVECTION WILL HOLD OFF UNTIL THE TUES NIGHT/WED TIME FRAME. DESPITE THIS UNCERTAINTY... THE OVERALL TREND NEXT WEEK WILL BE FOR WARMER AND MORE HUMID CONDITIONS WITH INCREASING CHANCES FOR THUNDERSTORMS. && .MARINE... UNSEASONABLE CONDITIONS ARE IN PLACE OVER THE CENTRAL GREAT LAKES TODAY AS COLD AIR ADVECTION IS ONGOING WITHIN A DEEP TROUGH AXIS. EFFICIENT NORTHERLY FLOW AND A LONG FETCH OVER THE WATERS WILL SUSTAIN HIGH WAVE ACTIVITY FROM SAGINAW BAY DOWN TO PORT HURON. RECENT WATER TEMPERATURE READINGS FROM THE BUOYS SUGGESTS THAT CONDITIONS WILL BE SOLIDLY IN THE NEUTRAL REGIME OUT OVER THE OPEN LAKE WHICH IS ATYPICAL FOR LATE MAY. IN FACT...CONDITIONS ARE UNSTABLE FOR SAGINAW BAY WITH WATER TEMPERATURE READINGS SUGGESTING LSTS ARE AT AROUND 13 TO 14 C VS AN 850MB TEMPERATURE THAT WILL BE DIPPING DOWN TO -4C BY 12Z THIS MORNING. WILL EXPAND THE ADVISORY TO INCLUDE INNER SAGINAW. CONDITIONS ARE MORE MARGINAL ON LAKE ST CLAIR AND LAKE ERIE. WILL GIVE RESPECT TO PEAK OF THE COLD AIR ADVECTION THAT WILL OCCUR THIS MORNING FOR THE SOUTHERN ZONES AND EXTEND THE SMALL CRAFT FOR THEM AS WELL. THE STABLE SURFACE ANTICYCLONE WILL BUILD INTO THE CENTRAL GREAT LAKES TONIGHT BRINGING A RETURN OF MUCH MORE FAMILIAR STABLE SEASON MARINE WEATHER. && .AVIATION...ISSUED 1146 PM EDT THU MAY 23 2013 //DISCUSSION... WHAT REMAINS OF LOW VFR TO HIGH MVFR BOUNDARY LAYER CLOUDS WILL WORK THEIR WAY THROUGH THE AREA WITHIN THE NEXT COUPLE OF HOURS. ONCE THAT OCCURS, CLEAR SKIES BELOW 10KFT WILL PREVAIL FOR THE BALANCE OF THE FORECAST PERIOD AS HIGH PRESSURE DOMINATES. DIURNAL HEATING WILL ALLOW NORTHERLY WINDS TO GUST TO AROUND 20 KTS DURING PEAK HEATING ON FRIDAY. //DTW THRESHOLD THREATS... * NONE && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 6 PM FRIDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CB LONG TERM....SC MARINE.......CB AVIATION.....JVC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1248 AM CDT FRI MAY 24 2013 .UPDATE... 06Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...THROUGH MONDAY ISSUED AT 204 PM CDT THU MAY 23 2013 23.12Z RAOBS SHOW GOOD 925-850MB COLD ADVECTION ACROSS THE WRN GREAT LAKES THIS MORNING IN MODERATE NORTHEAST FLOW. FRONTAL SLOPE OVER THE STATE IS SOMETHING THAT WILL COME INTO PLAY FOR UPCOMING FORECAST AND HOW FAR IT SLIDES SOUTHWEST. AT 12Z KINL-KABR HAD A 7C TEMPERATURE DIFFERENCE AT 850MB /12C AT 925MB/. A MASSIVE DRYING ACROSS MN OCCURRED OVERNIGHT WITH PRECIPITATELY WATER VALUES PLUMMETING FROM 0.90 TO 0.32 INCHES...OR 136 TO 48 PERCENT NORMAL. THE SURFACE RIDGE NOSING IN IS QUITE DRY WITH PRECIPITABLE WATER VALUES IN THE 30 PERCENT RANGE ACROSS SRN CANADA. THIS GAVE WAY TO A SUNNY BUT COOL DAY TODAY. A HIGHER AMPLITUDE RIDGE AXIS IS ANCHORED IN THE DAKOTAS AND SOUTH...WHILE A DEEPER CYCLONE HAS NOW SHIFTED ONSHORE INTO THE NWRN U.S. NUMEROUS SPOKES OF ENERGY ARE CIRCULATING AROUND THAT LOW...ONE OF WHICH IS QUITE STRONG OVER NEVADA WITH RAP ANALYSIS SHOWING A TROPOPAUSE FOLD TO NEAR 500MB...ON THE POLEWARD SIDE OF A MEASURED 100KT 250MB JET CORE NOSE. THIS IS DRIVING HEIGHT FALLS ACROSS MT/ID/UT. SURFACE DEW POINTS OF MEANING FOR CONVECTION ARE LOCATED IN OKLAHOMA...SOON TO RETURN NORTHWARD. FORECAST IS ON TRACK FOR CALMING WINDS TONIGHT AND CLEAR SKIES. WIDESPREAD FROST SHOULD OCCUR WITH LOWER 30S FORECAST ACROSS NWRN WI. WITH LOWER DEW POINTS OVER NWRN WI COUNTIES CURRENTLY...HAVE DECIDED TO JUST ADD ALL OF THOSE COUNTIES INTO THE FROST ADVISORY. BIG PICTURE DURING THIS PERIOD IS FALLING HEIGHTS AND PRESSURE IN THE FRONT RANGE WITH SOUTHERLY FLOW INCREASING AND A RETURN OF MOISTURE TO NEB/SD FRIDAY NIGHT. THIS WILL PLACE THE LOW-LEVEL THERMAL BOUNDARY ACROSS THE FORECAST AREA FROM 850-925MB...SLIGHTLY DISPLACED SWWRD...FROM KABR-KMLI. THE CONSENSUS NCEP MODELS AT 23.12Z REMAIN CONSISTENT WITH THEIR PREVIOUS RUNS ON THE FRONTAL BOUNDARY BECOMING ACTIVE IN THE DAKOTAS/NEB FRIDAY EVENING AND SHIFTING EAST INTO MN/IA OVERNIGHT. THE 23.00Z ECMWF/UKMET SOLUTIONS DO AS WELL...HOWEVER THEY REMAIN FURTHER WEST. THE 300/305K SURFACE IN THE NCEP SOLUTIONS REMAINS CONSISTENT WITH AN 8G/KG MOISTURE SURGE ISENTROPICALLY LIFTING AND CONVERGING INTO CENTRAL AND ERN MN FRIDAY OVERNIGHT WITH A FETCH OF ABOUT 500 J/KG OF MUCAPE FEEDING IT. THE NAM SEEMS TO BE THE MOST AGRESSIVE. NOT OVERLY IMPRESSIVE FOR SEVERE WEATHER...BUT RATHER THERE IS ENOUGH FORCING TO GENERATE RA/TSRA SWWRD OF MSP. THE ECMWF SOLUTIONS SUGGEST MORE OF A FOCUS IN SRN/SWRN MN. THE MAIN QUESTION IS HOW FAR EAST DOES THIS CONVECTIVE COMPLEX TRACK FRIDAY NIGHT AND HOW FAR EAST DOES THE FRONTAL BOUNDARY LIFT. HAVE INCREASED RAIN CHANCES FURTHER EAST FOR FRIDAY NIGHT AND SATURDAY...HOWEVER WITH THE VERIFICATION RECORD OF THE ECMWF...THERE IS STILL A CHANCE THE EASTERN AREAS WILL BE DRY. CONFIDENCE IS LOW ON THE EXACT LOCATION OF THE WEATHER...BUT HIGHER THAT IT WILL BE AN ACTIVE FRONTAL ZONE WITH SHRA/ISO TSRA. THIS QUESTION REMAINS THROUGH MONDAY...HOW FAR EAST WILL THE FRONTAL BAND BE LOCATED. THE FRONT WILL LIKELY REMAIN ACTIVE WITH SHOWERS/STORMS AND CLOUDS...AND HIGHS QUITE A BIT COOLER THAN OUTSIDE THE BAND. OVERALL...HAVE INCREASED RAIN CHANCES IN THE WRN/SRN FORECAST AREA AND TRIED TO REMAIN NEARLY DRY IN THE EAST. SEEMS LIKE IT WILL BE A CLOUDY WEEKEND...AND THUS HAVE LOWERED HIGHS SUNDAY AND MONDAY AS WELL. SEVERE WEATHER THREATS ARE MOST POSSIBLE IN SWRN MN CLOSER TO THE CAPE POOL...AND MONDAY LOOKS MOST FAVORABLE SHOULD THE INSTABILITY INCREASE AS THE WARM FRONT MOVES TOWARD MN. HOWEVER...ACTIVITY ALONG THAT FRONT THIS WEEKEND MAY HAVE MUCH TO DO WITH HOW THE ENVIRONMENT/FRONT EVOLVES MONDAY. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 241 PM CDT THU MAY 23 2013 IT CONTINUES TO LOOK LIKE WE/LL UNFORTUNATELY NEED TO KEEP A PROLONGED PERIOD OF CHANCE POPS IN THE FORECAST THROUGH THE WEEK AS THE BAROCLINIC ZONE LINGERS IN THE AREA... WITH ELEVATED INSTABILITY AND PERSISTENT WARM ADVECTION WORK TO GENERATE SCATTERED SHRA/TSRA. THERE WILL UNDOUBTEDLY BE SOME DRY PERIODS... WITH PCPN FOCUSED WHEN INDIVIDUAL SHORTWAVES RIPPLE SOUTHEAST THROUGH THE UPPER FLOW... BUT AT THIS POINT IT IS IMPOSSIBLE TO TRY AND PIN POINT WHEN SUCH DRY PERIODS MIGHT OCCUR. THE 12Z ECMWF HAS COME AROUND MORE IN LINE WITH THE GFS IN KEEPING THINGS MORE ACTIVE IN OUR AREA THROUGHOUT THE TIME PERIOD... ALTHOUGH BOTH SUGGEST WE SHOULD FINALLY BRING THE UPPER TROUGH EAST TOWARD THE REGION BY THE END OF THE WEEK. DEPENDING ON HOW THAT UNFOLDS... WE COULD HAVE A POSSIBILITY FOR FOCUSED CONVECTION AND POSSIBLE SEVERE WEATHER DURING THE THURSDAY-FRIDAY TIME FRAME. BUT... UNTIL THAT POINT THE MAIN ISSUES WOULD LIKELY BE LOCALLY HEAVY RAIN AND PERHAPS SOME HAIL. IN GENERAL... TEMPERATURES WILL WARM THROUGH THE WEEK AS THE BONAFIDE WARM SECTOR SLOWLY LIFTS NORTH INTO THE AREA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1248 AM CDT FRI MAY 24 2013 HIGH PRESSURE SLIDING INTO WI TONIGHT WILL PROVIDE EXCELLENT CONDITIONS THROUGH MUCH OF THE DAY FRIDAY...BUT GOING THROUGH THE DAY...WILL START TO SEE AN AREA OF SHRA/TSRA MOVE EAST THROUGH THE DAKOTAS. BASED ON MPX SOUNDING LAST NIGHT...AIRMASS OVER THE MPX AIRSPACE IS VERY DRY...WHICH SHOULD DELAY THE ONSET OF ANY PRECIP. DID NOT INTRODUCE ANY VCSH UNTIL AFTER 00Z...BUT QUICKLY SPREAD IT EAST ACROSS MN AS THE LLJ BEGINS NOSING INTO IOWA THIS EVENING. GIVEN DRY ANTECEDENT CONDITIONS...KEPT CONDS VFR AS IT WILL TAKE A WHILE TO MOISTEN THE LOW LEVELS...BUT BY 12Z SATURDAY...PROBABILITIES FOR MVFR OR LOWER CIGS WILL BE INCREASING PRECIPITOUSLY ACROSS MN. FOR WINDS...HIGH PRESSURE WILL BE SLIDING OVER TOWARD MICH OVER THE DAY...WITH GRADIENT INCREASING AS A RESULT. WINDS WILL BE STRONGEST WEST...WEAKEST EAST. BASED ON SOUNDINGS...EXPECT SOME STRONG SUSTAINED WINDS...WITH MINIMAL GUSTING. A 16G21KT TYPE DAY LOOKS TO AHEAD FOR WRN MN. KMSP...CONFIDENCE HIGH IN TAF PARAMETERS UNTIL THE TAIL END OF THE TAF. AT THIS POINT...KEPT ONLY A VCSH MENTION...THOUGH AT SOME POINT LATE FRIDAY NIGHT...DO EXPECT THERE TO BE A PERIOD OF SHRA/ISO TSRA. THIS WOULD BE MOST LIKELY BETWEEN 8Z AND 12Z. AS FOR CIGS...KEPT THEM VFR...THOUGH CHANCE FOR MVFR...INCLUDING SUB 017 CIGS INCREASES AFTER 8Z SAT. /OUTLOOK FOR KMSP/ SAT...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10-15 KTS. SUN...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10-15 KTS. MON...CHC MVFR OR LOWER CIGS. CHC SHRA/TSRA. WINDS SE 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...FROST ADVISORY UNTIL 7 AM CDT THIS MORNING FOR MNZ045-052-053- 063. WI...FROST ADVISORY UNTIL 7 AM CDT THIS MORNING FOR WIZ014>016- 023>028. && $$ SHORT TERM...BAUMGARDT/ARX LONG TERM... AVIATION...MPG
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
440 AM CDT FRI MAY 24 2013 .SHORT TERM... OVERALL CHANCES OF CONVECTION WILL BE LESS FAVORABLE TODAY THAN YESTERDAY. THERE IS AN OVERALL LACK OF FORCING BOTH LARGE AND AT THE MESOSCALE LEVEL. UPPER LEVEL JET WINDS WILL UNDERGO A SIGNIFICANT WEAKENING WITH A LACK OF A FOCUSED AREA OF UPPER LEVEL DIVERGENCE. SOUTHWEST FLOW ALOFT WILL CONTINUE TO PERSIST OVER THE REGION BUT THERE ARE NO DISCERNIBLE SHORT WAVES WITH THE FLOW FOR THIS AFTERNOON. ANY WELL DEFINED LOW LEVEL BOUNDARY WILL BE WELL AWAY FROM THE REGION WITH LITTLE TO NO LOW LEVEL FOCUS RESOLVED BY MODEL SOLUTIONS. THE ONLY LOW LEVEL BOUNDARY MAY BE A LEFT OVER CONVECTIVE BOUNDARY FROM CONVECTION EARLY THIS MORNING. OTHERWISE...THE ONLY LOW LEVEL ENHANCEMENT MAY BE ALONG THE EDGE OF THE CAPROCK WITH SOUTHEASTERLY WINDS. FURTHERMORE...ISENTROPIC SURFACES WILL BE COMPOSED OF DOWNGLIDE. THERE WILL BE NO SHORTAGE OF ATMOSPHERIC INSTABILITY. INSTABILITY WILL BALLOON TO BETWEEN 2000-3000 J/KG WITH MAXIMUM VALUES OVER THE ROLLING PLAINS WHERE MOISTURE IS DEEPEST. THE RAP EVEN SHOWS AN ASTOUNDING 6000 J/KG OF SURFACE BASED CAPE BY THE AFTERNOON. SURFACE DEW POINTS ARE NOT EXPECTED TO MIX OUT AS MUCH AS THEY DID ON THURSDAY. SOUTHEAST WINDS WILL KEEP SURFACE DEW POINTS IN JUICY TERRITORY RANGING FROM UPPER 50S TO MID 60S. PRECIPITABLE WATER VALUES MAINTAIN RESPECTABLE VALUES BETWEEN 1.00 AND 1.25 INCHES. HODOGRAPHS DEPICT GOOD TURNING IN LOW LEVELS BUT WIND SPEEDS ARE FAIRLY LIGHT THROUGH MID LEVELS. THIS IS ALSO REFLECTED IN DEEP LAYER SHEAR PROGS. SHEAR VECTORS FROM 0-6KM ARE ON THE ORDER OF ONLY 25-30KT. THIS WOULD LEAD TO FAIRLY SLOW STORM MOTIONS ALLOWING FOR A DELUGE OF RAINFALL. OVERALL...CONVECTION LOOKS TO BE POORLY ORGANIZED FOR TODAY. MODELS ARE ALSO INITIATING BY LATE IN THE MORNING WHICH SEEMS EQUIVOCAL GIVEN THAT THE ATMOSPHERE WILL REMAINED CAPPED UNTIL THE EARLY AFTERNOON AMONG OTHER REASONS DISCUSSED ABOVE. LASTLY...WITH DEW POINTS NOT ANTICIPATED TO MIX OUT NEARLY AS MUCH TODAY...TEMPERATURES WILL BE SIGNIFICANTLY COOLER THIS AFTERNOON WITH MOSTLY 80S FORECAST. JDV && .LONG TERM... SOUTHWEST FLOW ALOFT EXPECTED TO REMAIN OVER THE SOUTH PLAINS REGION THROUGH THE MIDDLE OF THE COMING WEEK. MOISTURE FLOW WILL CONTINUE NORTHWARD WITH PRECIPITABLE WATER VALUES HOLDING IN EXCESS OF AN INCH MORE OR LESS OVER THE CENTER OF THE AREA...LESS WEST AND MORE EAST OF COURSE. THE SURFACE DRY-LINE WILL LIKELY SLOSH MOSTLY BETWEEN THE WESTERN AND EASTERN SOUTH PLAINS DURING THIS PERIOD...WHILE PRECISE LOCATIONS AT PEAK AFTERNOON HEATING PERIODS REMAINS UNCERTAIN. INSTABILITY LEVELS ALSO EXPECTED TO HOLD IN THE 1000-2000 JOULES PER KILOGRAM RANGE. WEAK EJECTING DISTURBANCES MAY PROVIDE ENOUGH LIFT AT TIMES...WHILE WEAKLY CONVERGENT LOW LEVEL FLOW ALSO COULD GENERATE LOW COVERAGE THUNDER CHANCES THROUGH TUESDAY. A STRONGER TROUGH STILL SEEMS LIKELY TO EJECT LATE WEDNESDAY AND THURSDAY...PERHAPS IN TWO OR MORE PARTS LIKE THE GFS OR AS A STRONGER TROUGH OR UPPER LOW LIKE THE ECMWF. EITHER WAY SHOULD SUPPORT MORE BACKED UPPER FLOW AND EVEN DEEPER MOISTURE WEDNESDAY AND OR THURSDAY AND MAY END UP WITH A MORE WIDESPREAD SEVERE WEATHER THREAT AS WELL. THIS IS A STRONG ENOUGH AND CONSISTENT ENOUGH SIGNAL FOR NOW TO RAISE THUNDERSTORM MENTION INTO THE CHANCE CATEGORY WEDNESDAY. TEMPERATURES SHOULD WARM A BIT ABOVE NORMAL LATE IN THE WEEKEND AND EARLY NEXT WEEK...WHILE WINDS SHOULD INCREASE BY MID-WEEK WITH THE PASSING UPPER LOW OR LOW PRESSURE TROUGH. RMCQUEEN && .PRELIMINARY POINT TEMPS/POPS... FRIONA 84 60 84 60 93 / 30 30 20 20 20 TULIA 83 62 83 60 92 / 30 30 20 20 10 PLAINVIEW 83 63 83 61 91 / 30 30 20 20 10 LEVELLAND 85 64 84 62 92 / 30 30 20 20 10 LUBBOCK 83 65 83 63 92 / 30 30 20 20 10 DENVER CITY 85 64 84 61 92 / 30 30 20 20 10 BROWNFIELD 85 65 84 62 92 / 30 30 20 20 10 CHILDRESS 83 66 85 66 93 / 30 30 20 20 10 SPUR 82 66 82 63 91 / 30 30 20 20 10 ASPERMONT 85 67 84 66 92 / 40 40 20 20 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01/05
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1120 AM EDT FRI MAY 24 2013 .UPDATE (REST OF TODAY AND TONIGHT)... 15Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW AN ACTIVE UPPER LEVEL PATTERN IN PLACE OVER THE CONUS. LONGWAVE PATTERN IS DOMINATED BY DEEP TROUGHS ALONG BOTH THE PACIFIC AND ATLANTIC COASTS WHILE A LONGWAVE RIDGE AXIS BISECTS THE CONTINENT OVER THE CENTRAL PLAINS. OUR FORECAST AREA RESIDES AT THE BASE OF THE EASTERN CONUS TROUGH. A STRONG SHORTWAVE EMBEDDED WITHIN THIS TROUGH IS NOW DROPPING SOUTHEASTWARD OVER THE MID-ATLANTIC/CAROLINAS. THIS ENERGY WILL NOT ONLY ACT TO CLOSE OFF A POTENT UPPER LOW OFF THE NEW ENGLAND COAST...BUT ITS MOMENTUM WILL ALSO HELP DRIVE A LATE SEASON COLD FRONT DOWN AND THROUGH THE FLORIDA PENINSULA DURING THE NEXT 12-18 HOURS. 24/12Z KTBW SOUNDING PROFILE WAS DRY...BUT NOT UNSEASONABLY DRY...JUST YET. HOWEVER LOOKING UPSTREAM TOWARD BIRMINGHAM AND ATLANTA WE BEGIN TO SEE A MUCH DRIER AIRMASS ABOVE THE SURFACE WHICH WILL BE SETTLING SOUTHWARD AND OVER OUR HEADS FOR THE HOLIDAY WEEKEND. AT THE SURFACE...AS MENTIONED ABOVE...A LATE SEASON COLD FRONT IS READY TO ADVANCE THROUGH THE FORECAST AREA LATER TODAY AND TONIGHT. THE FRONT IS CURRENTLY ANALYZED UP NEAR THE I-10 CORRIDOR WITH A DISTINCT DEWPOINT DISCONTINUITY FROM MUCH OF THE FLORIDA PENINSULA UP TO THE INTERIOR PANHANDLE AND SOUTHERN PORTION OF AL/GA. THIS MORE COMFORTABLE AIRMASS IS ON ITS WAY TO US. SOME EARLY MORNING PATCHES OF FOG ARE ALL BUT GONE LATE THIS MORNING LEADING TO MOSTLY SUNNY SKIES REGION-WIDE. STILL HAVE ENOUGH BOUNDARY LAYER MOISTURE AND EVENTUAL SEA-BREEZE FOCUS TO EXPECT A SCT CUMULUS FIELD TO BECOME ESTABLISHED FOR THE AFTERNOON...MAINLY ALONG AND SOUTH OF THE I-4 CORRIDOR. CAN NOT RULE OUT THE POSSIBILITY FOR AN ISOLATED SHOWER OR 2 TO DEVELOP LATE AFTERNOON/EARLY EVENING TO THE SOUTH OF I-4 WHERE FRONTAL AND SEA-BREEZE CONVERGENCE ALIGN ENOUGH TO OVERCOME THE NO SO FAVORABLE TROP FOR DEEP CONVECTION. ONLY HAVE POPS AROUND 20% FOR THESE CENTRAL AND SOUTHERN ZONES...AND NO RAIN CHANCES NORTH OF I-4. ANY ISOLATED SHOWERS THAT DO DEVELOP WILL LIKELY BE SHORT-LIVED AS THEY QUICKLY ENTRAIN DRY AND HOSTILE THETA-E AIR ABOVE 700MB INTO THEIR COLUMN. TEMPERATURES THE REST OF THE DAY WILL BE SEASONABLE WITH MANY INLAND LOCATIONS PEAKING WITHIN A DEGREE OR TWO OF 90. TYPICAL FOR THIS TIME OF YEAR...DEVELOPING AND STRENGTHENING ONSHORE FLOW WILL KEEP TEMPERATURES IN THE 80S NEAR THE BEACHES. TONIGHT...SURFACE FRONT SLIPS SOUTH OF THE REGION FOLLOWED QUICKLY BY STRONG CONTINENTAL HIGH PRESSURE RIDGING DOWN FROM THE NORTH. A FAVORABLE NNE DRAINAGE FLOW WILL ALLOW SOME OF OUR NORTHERN AREAS AROUND LEVY/CITRUS COUNTIES TO DROP INTO THE MID/UPPER 50S TOWARD SUNRISE ON SATURDAY...WHILE THE REMAINDER OF THE REGION DROPS DOWN INTO THE 60S. ANY ISOLATED EVENING SHOWERS OVER THE FAR SOUTHERN ZONES WILL END WITH THE FRONTAL PASSAGE SETTING UP A DRY AND SEASONABLE PLEASANT OVERNIGHT PERIOD. ENJOY! && .AVIATION... VFR CONDITIONS WILL PREVAIL WITH AT THE MOST FEW-SCT CLOUDS. NORTH AND NORTHWEST WINDS...GUSTY AT TIMES THIS AFTERNOON. && .MARINE... WINDS WILL START TO INCREASE TO CAUTIONARY LEVELS FOR OFFSHORE ZONES TONIGHT INTO EARLY SATURDAY MORNING WITH WAVE HEIGHTS INCREASING TO UP TO 4 FEET. STRONG HIGH PRESSURE WILL BUILD NORTH OF THE STATE OVER THE HOLIDAY WEEKEND AND INTO THE MIDDLE OF NEXT WEEK. THIS WILL RESULT IN AN ELEVATED EASTERLY FLOW ACROSS THE WATERS...WITH PERIODS OF EXERCISE CAUTION AND ADVISORY HEADLINES NECESSARY FOR MOST MARINE ZONES...PARTICULARLY DURING THE EVENING AND OVERNIGHT HOURS. && .PRELIMINARY POINT TEMPS/POPS... TPA 89 69 90 66 / 10 10 0 0 FMY 91 70 91 65 / 20 20 0 0 GIF 93 67 89 63 / 20 10 0 0 SRQ 86 70 90 64 / 10 10 0 0 BKV 90 62 88 55 / 10 10 0 0 SPG 89 73 88 71 / 10 10 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE...MROCZKA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
829 AM MDT FRI MAY 24 2013 .UPDATE... ISSUED AT 819 AM MDT FRI MAY 24 2013 MADE A FEW CHANGES TO THE FORECAST FOR TODAY. THE FIRST BEING TO INCREASE THE WINDS FOR TODAY...ESPECIALLY DURING THE MORNING. WINDS HAVE BEEN VARYING QUITE A BIT OVER THE PAST COUPLE OF HOURS. HAVE BEEN CONTEMPLATING A WIND ADVISORY FOR THE WESTERN 2/3S OF THE AREA. BIGGEST UNCERTAINTY IS WILL THE SUSTAINED WINDS REMAIN AT 30 MPH OR CONTINUE TO VARY. IN ADDITION THE WINDS MAY STRENGTHEN DURING THE AFTERNOON BEHIND THE WARM FRONT. AT THIS POINT WILL ONLY INCREASE THE SUSTAINED WINDS TO JUST UNDER 30 MPH FOR THE REST OF THE DAY FOR THE MAJORITY OF THE AREA...WHICH IS JUST UNDER WIND ADVISORY CRITERIA. IF CRITERIA IS REACHED AM CONFIDENT IT WILL BE VERY LOW END. ALSO REMOVED THE MENTION OF FOG FOR ALL BUT EAST CENTRAL COLORADO THIS MORNING. WEB CAMS AT FIRST VIEW AND GENOA BOTH SHOW VISIBILITIES OF LESS THAN A MILE. DUE TO THE RATHER SMALL AREA BEING AFFECTED AND SINCE THE FOG WILL BEGIN TO LIFT IN THE NEXT HOUR OR SO...WILL NOT BE ISSUING ANY FOG RELATED HAZARDS. DID DROP THE CHANCES FOR PRECIP. DOWN SOME THIS MORNING OVER THE EAST. MODELS DO SHOW A MINOR UPPER LEVEL SHORT WAVE TROUGH MOVING THROUGH...HOWEVER SOUNDINGS DO NOT LOOK VERY FAVORABLE FOR STORM DEVELOPMENT THIS MORNING. WILL LEAVE A SLIGHT CHANCE IN...BUT THIS MAY BE TOO MUCH FOR THE MORNING. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 434 AM MDT FRI MAY 24 2013 FORECAST PROBLEMS WILL BE NUMEROUS THROUGH THE WEEKEND. SATELLITE SHOWING A FASTER/MORE PROGRESSIVE FLOW OVER THE PACIFIC WHICH THEN TRANSITIONS TO A SLOWER AND MORE AMPLIFIED FLOW OVER NORTH AMERICA. THE RIDGE OVER THE CENTRAL PORTION OF THE COUNTRY HAS INCREASED IN AMPLITUDE OVER THE LAST 24 HOURS. UPPER LOW OVER THE PACIFIC NORTHWEST HAS MOVED LITTLE IN THE LAST 24 HOURS. FRONT THAT MOVED THROUGH YESTERDAY REMAINS DRAPED WELL SOUTH AND WEST OF THE AREA AT THIS TIME. THE SREF...NAM AND CANADIAN INITIALIZED BEST ON THE JET LEVEL WINDS OVER OUR AREA. MODELS HAVING A LITTLE TROUBLE WITH THE DETAILS AT MID LEVELS. OVERALL THE SREF AND NAM WERE DOING SLIGHTLY BETTER THAN THE GFS...CANADIAN AND CANADIAN. THE NAM LOOKED LIKE IT WAS CATCHING THE MINOR SHORTWAVE TROUGH TO OUR SOUTHWEST THE BEST. THE GFS WAS DOING SLIGHTLY BETTER THAN THE ECMWF ON THE LOW LEVEL THERMAL FIELD. THE GFS WAS TOO AGGRESSIVE WITH THE LOW LEVEL MOISTURE RETURN WITH THE NAM DOING A LITTLE BETTER. MODELS DO NOT QUITE HAVE THE BOUNDARY TO OUR SOUTH QUITE FAR ENOUGH SOUTH. THE NAM WAS DOING A LITTLE BETTER HERE. ALSO MODELS HAD QPF TOO FAR NORTH BY 06Z WITH THE GFS... CANADIAN AND THE SREF THE WORST OFFENDERS. AGAIN THE NAM WAS DOING BETTER HERE. TODAY/TONIGHT...MOST OF THE MODEL OUTPUT SHOWS A WEAK LEFT FRONT QUADRANT OVER THE AREA BEGINNING NEAR 12Z AND MAINLY AFFECTING THE SOUTHEAST HALF. A SMALL CLUSTER OF THUNDERSTORMS HAD DEVELOPED OVER NORTHEAST NEW MEXICO AND THE PANHANDLE AREA. THIS LOOKS TO BE IN RESPONSE TO SHORTWAVE TROUGH AND THE WEAK LEFT FRONT QUADRANT OF THE JET. HOWEVER THAT DISSIPATED WITH ISOLATED THUNDERSTORMS DEVELOPING OVER/NEAR THE EASTERN PORTION OF THE AREA. THE NAM FOR THE MOST PART HAS THIS AREA DEPICTED WELL...ESPECIALLY FOR THE JET. SO GOING BY THAT...WILL HAVE A SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS THROUGH MAINLY THE MORNING WITH IT POSSIBLY LINGERING INTO EARLY AFTERNOON IN THE FAR EAST. STRATUS IS MOSTLY OCCURRING OVER THE AREA AT THIS TIME WITH THE FOG CONFINED TO EASTERN COLORADO. THIS MAKES SENSE WITH THIS BEING THE MAIN AREA OF LOW LEVEL TRANSPORT OF MOISTURE AT THIS TIME. THE HRRR AND NAM INDICATE THE BEST CHANCE OF FOG OVER THE WESTERN HALF OF THE AREA. A FEW SPOTS ALSO REPORTING DRIZZLE AND SOUNDINGS WOULD INDICATE THAT WILL CONTINUE INTO THIS MORNING. SO WILL HAVE AREAS OF FOG WITH PATCHY DRIZZLE IN THE WESTERN HALF AND PATCHY FOG FURTHER EAST. SOUTHERLY WINDS INCREASE INTO THE WINDY CATEGORY. GRADIENT DEFINITELY SUPPORTS NEAR ADVISORY CRITERIA IN THE WEST BUT THERE THE 3 HOUR PRESSURE FALLS ARE NOT THAT HIGH. GLD VWP DEFINITELY WOULD SUPPORT WINDY. WILL RAISE WINDS TO NEAR ADVISORY IN THE FAR WEST. NOW FOR THE PRECIPITATION CHANCES DURING THE AFTERNOON AND NIGHT. SUBSIDENCE/DRYING OCCURS OUT EAST RATHER QUICKLY AFTER FIRST SHORTWAVE. INSTABILITY AXIS...BEST HEATING...MID/UPPER LEVEL LIFT AND SURFACE CONVERGENCE DEVELOPS NEAR OR OVER THE WESTERN PORTION OF THE AREA. SO WILL GRADUALLY RAMP UP POPS DURING THE AFTERNOON. BEST LIFT AND MOISTURE LOOK TO RESIDE OVER THE NORTH DURING THE NIGHT AND HAVE INCREASED POPS OVER THE NORTH WITH LOWER POPS FURTHER SOUTH. THUNDERSTORMS LOOK TO BE DONE BY 12Z. LOW LEVEL MOISTURE INCREASES OVER THE EASTERN HALF TO TWO THIRDS AFTER 06Z. AT THIS TIME MODELS INDICATING MOSTLY STRATUS. WILL INSERT FOG WITH THE GREATEST CHANCE IN THE FAR EAST. NOT A GOOD FEEL ON THE MAXES WITH THEM BEING DETERMINED BY THE EXTENT OF THE STRATUS AND HOW LONG IT TAKES TO BURN OFF. IT IS POSSIBLE THAT THICK CLOUD COVER WILL NOT BREAK UP UNTIL LATE MORNING. SO TRENDED THE FORECAST COOLER. SATURDAY/SATURDAY NIGHT...FOG WILL CLEAR OUT DURING THE MORNING. MODELS NOT AGREEING WHERE DRY LINE ENDS UP...WHERE THE INSTABILITY AXIS ENDS UP...WHERE THE CAP IS THE LEAST...AND SHORTWAVE DETAILS. AT THIS TIME IT LOOKS LIKE THE DRY LINE ENDS UP NEAR OR A LITTLE WEST OF THE COLORADO BORDER. ONE SHORTWAVE TROUGH EXITS THE EASTERN PORTION OF THE AREA EARLY IN THE AFTERNOON WITH ANOTHER ONE APPROACHING LATE IN THE AFTERNOON WITH THE BRUNT OF ITS LIFT COMING THROUGH DURING THE NIGHT. MODELS ARE GENERATING QPF WHERE THERE IS A STRONG CAP. AS IT LOOKS NOW THE MAIN TIME FOR PRECIPITATION WILL WAIT TO BEGIN UNTIL MID TO LATE EVENING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE EAST OF THE COLORADO BORDER...AND ESPECIALLY IN THE FAR EAST. LOW LEVEL THERMAL FIELD IS MUCH WARMER THAN TODAYS. HOWEVER...IF STRATUS/FOG LAST LONGER OR THE LEE TROUGH IS STRONGER/FURTHER WEST... THE WINDS WILL BE MORE FROM AN EASTERLY DIRECTION AND NOT ALLOW FOR AS BIG A WARM UP. KEPT THE WESTERN AREAS WARMER WITH COOLER MAXES FURTHER EAST. IN REGARDS TO FIRE...THE LOWEST RHS LOOK TO BE IN COLORADO AT THIS TIME. HOWEVER...THAT IS WHERE THE LIGHTEST WIND FIELD IS. DUE TO A LOT OF UNCERTAINTY...WAS NOT CONFIDENT ENOUGH TO THROW OUT A WATCH. WILL HIGHLIGHT IN THE FIRE WEATHER FORECAST AND HWO. SUNDAY/SUNDAY NIGHT...A LOT MORE DISAGREEMENT IN DETAILS SHOW UP IN THIS PERIOD. CURRENT MODEL OUTPUT SUPPORTED THE GOING PRECIPITATION FORECAST FOR THIS PERIOD AND LEFT IT ALONE. ALSO ONLY MADE SLIGHT ADJUSTMENTS TO THE TEMPERATURE FORECAST AS WELL. P .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 235 AM MDT FRI MAY 24 2013 MEDIUM RANGE MODEL DIFFERENCES EMERGE EARLY IN THE EXTENDED PERIOD...PARTICULARLY WITH REGARD TO AMPLITUDE OF UPPER FLOW PATTERN. THE ECMWF IS MORE AMPLIFIED ON MONDAY WITH BOTH THE UPPER RIDGE POSITIONED TO OUR EAST AND ALSO THE WESTERN CONUS UPPER TROUGH. THE POSITION OF THESE FEATURES WILL PLACE OUR AREA IN SOUTHWESTERLY FLOW ALOFT WITH THE LIKELIHOOD OF WEAK EMBEDDED DIFFICULT TO TIME SHORTWAVES THAT COULD POTENTIALLY ENHANCE PRECIPITATION DEVELOPMENT. BY TUESDAY THE PATTERN AMPLIFIES FURTHER AND ECMWF CLOSES OFF AN UPPER LOW OVER THE SOUTHWEST CONUS. GFS MAINTAINS AN OPEN WAVE AND SHIFTS IT EASTWARD WITH NOTICEABLE HEIGHT FALLS OVER OUR AREA BY LATE TUESDAY AND ESPECIALLY WEDNESDAY. THE NEW 00Z ECMWF HAS TRENDED THE DIRECTION OF THE MORE PROGRESSIVE GFS AND OPENS UP THE SOUTHWEST CONUS UPPER LOW RATHER THAN KEEP IT CLOSED AND SLOWLY MOVING IT EAST AS THE 12Z ECMWF INDICATED. STILL THE ECMWF IS CONSIDERABLY SLOWER THAN THE GFS WITH THE EASTWARD PROGRESSION OF THIS TROUGH. THIS LEADS TO A LOW CONFIDENCE FORECAST NEXT WEEK. GFS WOULD FAVOR A POTENTIALLY WIDESPREAD PRECIPITATION / ORGANIZED CONVECTIVE EVENT WEDNESDAY WHILE THE ECMWF SOLUTION WOULD SUPPORT A SIMILAR SITUATION BY LATE WEDNESDAY / WEDNESDAY NIGHT INTO THURSDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 546 AM MDT FRI MAY 24 2013 IFR CONDITIONS CURRENTLY AT GLD DUE TO LOW CIGS. THIS SHOULD PERSIST IN THE NEAR TERM FOLLOWED BY AN INCREASE TO MVFR AFTER AROUND 15-16Z AND EVENTUALLY VFR THIS AFTERNOON. MEANWHILE MVFR CONDITIONS MAY PERSIST A LITTLE LONGER AT MCK. SOME UNCERTAINTY WITH REGARD TO CONVECTION LATER THIS EVENING AND TONIGHT SO OPTED TO LEAVE VCTS OUT FOR NOW. THIS MAY NEED TO BE ADDED AT A LATER TIME IF CONFIDENCE INCREASES. LATER TONIGHT VFR CONDITIONS DUE TO CIGS ARE EXPECTED AT MCK. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...BULLER LONG TERM...BRB AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
550 AM MDT FRI MAY 24 2013 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 434 AM MDT FRI MAY 24 2013 FORECAST PROBLEMS WILL BE NUMEROUS THROUGH THE WEEKEND. SATELLITE SHOWING A FASTER/MORE PROGRESSIVE FLOW OVER THE PACIFIC WHICH THEN TRANSITIONS TO A SLOWER AND MORE AMPLIFIED FLOW OVER NORTH AMERICA. THE RIDGE OVER THE CENTRAL PORTION OF THE COUNTRY HAS INCREASED IN AMPLITUDE OVER THE LAST 24 HOURS. UPPER LOW OVER THE PACIFIC NORTHWEST HAS MOVED LITTLE IN THE LAST 24 HOURS. FRONT THAT MOVED THROUGH YESTERDAY REMAINS DRAPED WELL SOUTH AND WEST OF THE AREA AT THIS TIME. THE SREF...NAM AND CANADIAN INITIALIZED BEST ON THE JET LEVEL WINDS OVER OUR AREA. MODELS HAVING A LITTLE TROUBLE WITH THE DETAILS AT MID LEVELS. OVERALL THE SREF AND NAM WERE DOING SLIGHTLY BETTER THAN THE GFS...CANADIAN AND CANADIAN. THE NAM LOOKED LIKE IT WAS CATCHING THE MINOR SHORTWAVE TROUGH TO OUR SOUTHWEST THE BEST. THE GFS WAS DOING SLIGHTLY BETTER THAN THE ECMWF ON THE LOW LEVEL THERMAL FIELD. THE GFS WAS TOO AGGRESSIVE WITH THE LOW LEVEL MOISTURE RETURN WITH THE NAM DOING A LITTLE BETTER. MODELS DO NOT QUITE HAVE THE BOUNDARY TO OUR SOUTH QUITE FAR ENOUGH SOUTH. THE NAM WAS DOING A LITTLE BETTER HERE. ALSO MODELS HAD QPF TOO FAR NORTH BY 06Z WITH THE GFS... CANADIAN AND THE SREF THE WORST OFFENDERS. AGAIN THE NAM WAS DOING BETTER HERE. TODAY/TONIGHT...MOST OF THE MODEL OUTPUT SHOWS A WEAK LEFT FRONT QUADRANT OVER THE AREA BEGINNING NEAR 12Z AND MAINLY AFFECTING THE SOUTHEAST HALF. A SMALL CLUSTER OF THUNDERSTORMS HAD DEVELOPED OVER NORTHEAST NEW MEXICO AND THE PANHANDLE AREA. THIS LOOKS TO BE IN RESPONSE TO SHORTWAVE TROUGH AND THE WEAK LEFT FRONT QUADRANT OF THE JET. HOWEVER THAT DISSIPATED WITH ISOLATED THUNDERSTORMS DEVELOPING OVER/NEAR THE EASTERN PORTION OF THE AREA. THE NAM FOR THE MOST PART HAS THIS AREA DEPICTED WELL...ESPECIALLY FOR THE JET. SO GOING BY THAT...WILL HAVE A SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS THROUGH MAINLY THE MORNING WITH IT POSSIBLY LINGERING INTO EARLY AFTERNOON IN THE FAR EAST. STRATUS IS MOSTLY OCCURRING OVER THE AREA AT THIS TIME WITH THE FOG CONFINED TO EASTERN COLORADO. THIS MAKES SENSE WITH THIS BEING THE MAIN AREA OF LOW LEVEL TRANSPORT OF MOISTURE AT THIS TIME. THE HRRR AND NAM INDICATE THE BEST CHANCE OF FOG OVER THE WESTERN HALF OF THE AREA. A FEW SPOTS ALSO REPORTING DRIZZLE AND SOUNDINGS WOULD INDICATE THAT WILL CONTINUE INTO THIS MORNING. SO WILL HAVE AREAS OF FOG WITH PATCHY DRIZZLE IN THE WESTERN HALF AND PATCHY FOG FURTHER EAST. SOUTHERLY WINDS INCREASE INTO THE WINDY CATEGORY. GRADIENT DEFINITELY SUPPORTS NEAR ADVISORY CRITERIA IN THE WEST BUT THERE THE 3 HOUR PRESSURE FALLS ARE NOT THAT HIGH. GLD VWP DEFINITELY WOULD SUPPORT WINDY. WILL RAISE WINDS TO NEAR ADVISORY IN THE FAR WEST. NOW FOR THE PRECIPITATION CHANCES DURING THE AFTERNOON AND NIGHT. SUBSIDENCE/DRYING OCCURS OUT EAST RATHER QUICKLY AFTER FIRST SHORTWAVE. INSTABILITY AXIS...BEST HEATING...MID/UPPER LEVEL LIFT AND SURFACE CONVERGENCE DEVELOPS NEAR OR OVER THE WESTERN PORTION OF THE AREA. SO WILL GRADUALLY RAMP UP POPS DURING THE AFTERNOON. BEST LIFT AND MOISTURE LOOK TO RESIDE OVER THE NORTH DURING THE NIGHT AND HAVE INCREASED POPS OVER THE NORTH WITH LOWER POPS FURTHER SOUTH. THUNDERSTORMS LOOK TO BE DONE BY 12Z. LOW LEVEL MOISTURE INCREASES OVER THE EASTERN HALF TO TWO THIRDS AFTER 06Z. AT THIS TIME MODELS INDICATING MOSTLY STRATUS. WILL INSERT FOG WITH THE GREATEST CHANCE IN THE FAR EAST. NOT A GOOD FEEL ON THE MAXES WITH THEM BEING DETERMINED BY THE EXTENT OF THE STRATUS AND HOW LONG IT TAKES TO BURN OFF. IT IS POSSIBLE THAT THICK CLOUD COVER WILL NOT BREAK UP UNTIL LATE MORNING. SO TRENDED THE FORECAST COOLER. SATURDAY/SATURDAY NIGHT...FOG WILL CLEAR OUT DURING THE MORNING. MODELS NOT AGREEING WHERE DRYLINE ENDS UP...WHERE THE INSTABILITY AXIS ENDS UP...WHERE THE CAP IS THE LEAST...AND SHORTWAVE DETAILS. AT THIS TIME IT LOOKS LIKE THE DRY LINE ENDS UP NEAR OR A LITTLE WEST OF THE COLORADO BORDER. ONE SHORTWAVE TROUGH EXITS THE EASTERN PORTION OF THE AREA EARLY IN THE AFTERNOON WITH ANOTHER ONE APPROACHING LATE IN THE AFTERNOON WITH THE BRUNT OF ITS LIFT COMING THROUGH DURING THE NIGHT. MODELS ARE GENERATING QPF WHERE THERE IS A STRONG CAP. AS IT LOOKS NOW THE MAIN TIME FOR PRECIPITATION WILL WAIT TO BEGIN UNTIL MID TO LATE EVENING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE EAST OF THE COLORADO BORDER...AND ESPECIALLY IN THE FAR EAST. LOW LEVEL THERMAL FIELD IS MUCH WARMER THAN TODAYS. HOWEVER...IF STRATUS/FOG LAST LONGER OR THE LEE TROUGH IS STRONGER/FURTHER WEST... THE WINDS WILL BE MORE FROM AN EASTERLY DIRECTION AND NOT ALLOW FOR AS BIG A WARMUP. KEPT THE WESTERN AREAS WARMER WITH COOLER MAXES FURTHER EAST. IN REGARDS TO FIRE...THE LOWEST RHS LOOK TO BE IN COLORADO AT THIS TIME. HOWEVER...THAT IS WHERE THE LIGHTEST WIND FIELD IS. DUE TO A LOT OF UNCERTAINTY...WAS NOT CONFIDENT ENOUGH TO THROW OUT A WATCH. WILL HIGHLIGHT IN THE FIRE WEATHER FORECAST AND HWO. SUNDAY/SUNDAY NIGHT...A LOT MORE DISAGREEMENT IN DETAILS SHOW UP IN THIS PERIOD. CURRENT MODEL OUTPUT SUPPORTED THE GOING PRECIPITATION FORECAST FOR THIS PERIOD AND LEFT IT ALONE. ALSO ONLY MADE SLIGHT ADJUSTMENTS TO THE TEMPERATURE FORECAST AS WELL. P .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 235 AM MDT FRI MAY 24 2013 MEDIUM RANGE MODEL DIFFERENCES EMERGE EARLY IN THE EXTENDED PERIOD...PARTICULARLY WITH REGARD TO AMPLITUDE OF UPPER FLOW PATTERN. THE ECMWF IS MORE AMPLIFIED ON MONDAY WITH BOTH THE UPPER RIDGE POSITIONED TO OUR EAST AND ALSO THE WESTERN CONUS UPPER TROUGH. THE POSITION OF THESE FEATURES WILL PLACE OUR AREA IN SOUTHWESTERLY FLOW ALOFT WITH THE LIKELIHOOD OF WEAK EMBEDDED DIFFICULT TO TIME SHORTWAVES THAT COULD POTENTIALLY ENHANCE PRECIPITATION DEVELOPMENT. BY TUESDAY THE PATTERN AMPLIFIES FURTHER AND ECMWF CLOSES OFF AN UPPER LOW OVER THE SOUTHWEST CONUS. GFS MAINTAINS AN OPEN WAVE AND SHIFTS IT EASTWARD WITH NOTICEABLE HEIGHT FALLS OVER OUR AREA BY LATE TUESDAY AND ESPECIALLY WEDNESDAY. THE NEW 00Z ECMWF HAS TRENDED THE DIRECTION OF THE MORE PROGRESSIVE GFS AND OPENS UP THE SOUTHWEST CONUS UPPER LOW RATHER THAN KEEP IT CLOSED AND SLOWLY MOVING IT EAST AS THE 12Z ECMWF INDICATED. STILL THE ECMWF IS CONSIDERABLY SLOWER THAN THE GFS WITH THE EASTWARD PROGRESSION OF THIS TROUGH. THIS LEADS TO A LOW CONFIDENCE FORECAST NEXT WEEK. GFS WOULD FAVOR A POTENTIALLY WIDESPREAD PRECIPITATION / ORGANIZED CONVECTIVE EVENT WEDNESDAY WHILE THE ECMWF SOLUTION WOULD SUPPORT A SIMILAR SITUATION BY LATE WEDNESDAY / WEDNESDAY NIGHT INTO THURSDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 546 AM MDT FRI MAY 24 2013 IFR CONDITIONS CURRENTLY AT GLD DUE TO LOW CIGS. THIS SHOULD PERSIST IN THE NEAR TERM FOLLOWED BY AN INCREASE TO MVFR AFTER AROUND 15-16Z AND EVENTUALLY VFR THIS AFTERNOON. MEANWHILE MVFR CONDITIONS MAY PERSIST A LITTLE LONGER AT MCK. SOME UNCERTAINTY WITH REGARD TO CONVECTION LATER THIS EVENING AND TONIGHT SO OPTED TO LEAVE VCTS OUT FOR NOW. THIS MAY NEED TO BE ADDED AT A LATER TIME IF CONFIDENCE INCREASES. LATER TONIGHT VFR CONDITIONS DUE TO CIGS ARE EXPECTED AT MCK. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...BRB AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
434 AM MDT FRI MAY 24 2013 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 434 AM MDT FRI MAY 24 2013 FORECAST PROBLEMS WILL BE NUMEROUS THROUGH THE WEEKEND. SATELLITE SHOWING A FASTER/MORE PROGRESSIVE FLOW OVER THE PACIFIC WHICH THEN TRANSITIONS TO A SLOWER AND MORE AMPLIFIED FLOW OVER NORTH AMERICA. THE RIDGE OVER THE CENTRAL PORTION OF THE COUNTRY HAS INCREASED IN AMPLITUDE OVER THE LAST 24 HOURS. UPPER LOW OVER THE PACIFIC NORTHWEST HAS MOVED LITTLE IN THE LAST 24 HOURS. FRONT THAT MOVED THROUGH YESTERDAY REMAINS DRAPED WELL SOUTH AND WEST OF THE AREA AT THIS TIME. THE SREF...NAM AND CANADIAN INITIALIZED BEST ON THE JET LEVEL WINDS OVER OUR AREA. MODELS HAVING A LITTLE TROUBLE WITH THE DETAILS AT MID LEVELS. OVERALL THE SREF AND NAM WERE DOING SLIGHTLY BETTER THAN THE GFS...CANADIAN AND CANADIAN. THE NAM LOOKED LIKE IT WAS CATCHING THE MINOR SHORTWAVE TROUGH TO OUR SOUTHWEST THE BEST. THE GFS WAS DOING SLIGHTLY BETTER THAN THE ECMWF ON THE LOW LEVEL THERMAL FIELD. THE GFS WAS TOO AGGRESSIVE WITH THE LOW LEVEL MOISTURE RETURN WITH THE NAM DOING A LITTLE BETTER. MODELS DO NOT QUITE HAVE THE BOUNDARY TO OUR SOUTH QUITE FAR ENOUGH SOUTH. THE NAM WAS DOING A LITTLE BETTER HERE. ALSO MODELS HAD QPF TOO FAR NORTH BY 06Z WITH THE GFS... CANADIAN AND THE SREF THE WORST OFFENDERS. AGAIN THE NAM WAS DOING BETTER HERE. TODAY/TONIGHT...MOST OF THE MODEL OUTPUT SHOWS A WEAK LEFT FRONT QUADRANT OVER THE AREA BEGINNING NEAR 12Z AND MAINLY AFFECTING THE SOUTHEAST HALF. A SMALL CLUSTER OF THUNDERSTORMS HAD DEVELOPED OVER NORTHEAST NEW MEXICO AND THE PANHANDLE AREA. THIS LOOKS TO BE IN RESPONSE TO SHORTWAVE TROUGH AND THE WEAK LEFT FRONT QUADRANT OF THE JET. HOWEVER THAT DISSIPATED WITH ISOLATED THUNDERSTORMS DEVELOPING OVER/NEAR THE EASTERN PORTION OF THE AREA. THE NAM FOR THE MOST PART HAS THIS AREA DEPICTED WELL...ESPECIALLY FOR THE JET. SO GOING BY THAT...WILL HAVE A SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS THROUGH MAINLY THE MORNING WITH IT POSSIBLY LINGERING INTO EARLY AFTERNOON IN THE FAR EAST. STRATUS IS MOSTLY OCCURRING OVER THE AREA AT THIS TIME WITH THE FOG CONFINED TO EASTERN COLORADO. THIS MAKES SENSE WITH THIS BEING THE MAIN AREA OF LOW LEVEL TRANSPORT OF MOISTURE AT THIS TIME. THE HRRR AND NAM INDICATE THE BEST CHANCE OF FOG OVER THE WESTERN HALF OF THE AREA. A FEW SPOTS ALSO REPORTING DRIZZLE AND SOUNDINGS WOULD INDICATE THAT WILL CONTINUE INTO THIS MORNING. SO WILL HAVE AREAS OF FOG WITH PATCHY DRIZZLE IN THE WESTERN HALF AND PATCHY FOG FURTHER EAST. SOUTHERLY WINDS INCREASE INTO THE WINDY CATEGORY. GRADIENT DEFINITELY SUPPORTS NEAR ADVISORY CRITERIA IN THE WEST BUT THERE THE 3 HOUR PRESSURE FALLS ARE NOT THAT HIGH. GLD VWP DEFINITELY WOULD SUPPORT WINDY. WILL RAISE WINDS TO NEAR ADVISORY IN THE FAR WEST. NOW FOR THE PRECIPITATION CHANCES DURING THE AFTERNOON AND NIGHT. SUBSIDENCE/DRYING OCCURS OUT EAST RATHER QUICKLY AFTER FIRST SHORTWAVE. INSTABILITY AXIS...BEST HEATING...MID/UPPER LEVEL LIFT AND SURFACE CONVERGENCE DEVELOPS NEAR OR OVER THE WESTERN PORTION OF THE AREA. SO WILL GRADUALLY RAMP UP POPS DURING THE AFTERNOON. BEST LIFT AND MOISTURE LOOK TO RESIDE OVER THE NORTH DURING THE NIGHT AND HAVE INCREASED POPS OVER THE NORTH WITH LOWER POPS FURTHER SOUTH. THUNDERSTORMS LOOK TO BE DONE BY 12Z. LOW LEVEL MOISTURE INCREASES OVER THE EASTERN HALF TO TWO THIRDS AFTER 06Z. AT THIS TIME MODELS INDICATING MOSTLY STRATUS. WILL INSERT FOG WITH THE GREATEST CHANCE IN THE FAR EAST. NOT A GOOD FEEL ON THE MAXES WITH THEM BEING DETERMINED BY THE EXTENT OF THE STRATUS AND HOW LONG IT TAKES TO BURN OFF. IT IS POSSIBLE THAT THICK CLOUD COVER WILL NOT BREAK UP UNTIL LATE MORNING. SO TRENDED THE FORECAST COOLER. SATURDAY/SATURDAY NIGHT...FOG WILL CLEAR OUT DURING THE MORNING. MODELS NOT AGREEING WHERE DRYLINE ENDS UP...WHERE THE INSTABILITY AXIS ENDS UP...WHERE THE CAP IS THE LEAST...AND SHORTWAVE DETAILS. AT THIS TIME IT LOOKS LIKE THE DRY LINE ENDS UP NEAR OR A LITTLE WEST OF THE COLORADO BORDER. ONE SHORTWAVE TROUGH EXITS THE EASTERN PORTION OF THE AREA EARLY IN THE AFTERNOON WITH ANOTHER ONE APPROACHING LATE IN THE AFTERNOON WITH THE BRUNT OF ITS LIFT COMING THROUGH DURING THE NIGHT. MODELS ARE GENERATING QPF WHERE THERE IS A STRONG CAP. AS IT LOOKS NOW THE MAIN TIME FOR PRECIPITATION WILL WAIT TO BEGIN UNTIL MID TO LATE EVENING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE EAST OF THE COLORADO BORDER...AND ESPECIALLY IN THE FAR EAST. LOW LEVEL THERMAL FIELD IS MUCH WARMER THAN TODAYS. HOWEVER...IF STRATUS/FOG LAST LONGER OR THE LEE TROUGH IS STRONGER/FURTHER WEST... THE WINDS WILL BE MORE FROM AN EASTERLY DIRECTION AND NOT ALLOW FOR AS BIG A WARMUP. KEPT THE WESTERN AREAS WARMER WITH COOLER MAXES FURTHER EAST. IN REGARDS TO FIRE...THE LOWEST RHS LOOK TO BE IN COLORADO AT THIS TIME. HOWEVER...THAT IS WHERE THE LIGHTEST WIND FIELD IS. DUE TO A LOT OF UNCERTAINTY...WAS NOT CONFIDENT ENOUGH TO THROW OUT A WATCH. WILL HIGHLIGHT IN THE FIRE WEATHER FORECAST AND HWO. SUNDAY/SUNDAY NIGHT...A LOT MORE DISAGREEMENT IN DETAILS SHOW UP IN THIS PERIOD. CURRENT MODEL OUTPUT SUPPORTED THE GOING PRECIPITATION FORECAST FOR THIS PERIOD AND LEFT IT ALONE. ALSO ONLY MADE SLIGHT ADJUSTMENTS TO THE TEMPERATURE FORECAST AS WELL. P .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 235 AM MDT FRI MAY 24 2013 MEDIUM RANGE MODEL DIFFERENCES EMERGE EARLY IN THE EXTENDED PERIOD...PARTICULARLY WITH REGARD TO AMPLITUDE OF UPPER FLOW PATTERN. THE ECMWF IS MORE AMPLIFIED ON MONDAY WITH BOTH THE UPPER RIDGE POSITIONED TO OUR EAST AND ALSO THE WESTERN CONUS UPPER TROUGH. THE POSITION OF THESE FEATURES WILL PLACE OUR AREA IN SOUTHWESTERLY FLOW ALOFT WITH THE LIKELIHOOD OF WEAK EMBEDDED DIFFICULT TO TIME SHORTWAVES THAT COULD POTENTIALLY ENHANCE PRECIPITATION DEVELOPMENT. BY TUESDAY THE PATTERN AMPLIFIES FURTHER AND ECMWF CLOSES OFF AN UPPER LOW OVER THE SOUTHWEST CONUS. GFS MAINTAINS AN OPEN WAVE AND SHIFTS IT EASTWARD WITH NOTICEABLE HEIGHT FALLS OVER OUR AREA BY LATE TUESDAY AND ESPECIALLY WEDNESDAY. THE NEW 00Z ECMWF HAS TRENDED THE DIRECTION OF THE MORE PROGRESSIVE GFS AND OPENS UP THE SOUTHWEST CONUS UPPER LOW RATHER THAN KEEP IT CLOSED AND SLOWLY MOVING IT EAST AS THE 12Z ECMWF INDICATED. STILL THE ECMWF IS CONSIDERABLY SLOWER THAN THE GFS WITH THE EASTWARD PROGRESSION OF THIS TROUGH. THIS LEADS TO A LOW CONFIDENCE FORECAST NEXT WEEK. GFS WOULD FAVOR A POTENTIALLY WIDESPREAD PRECIPITATION / ORGANIZED CONVECTIVE EVENT WEDNESDAY WHILE THE ECMWF SOLUTION WOULD SUPPORT A SIMILAR SITUATION BY LATE WEDNESDAY / WEDNESDAY NIGHT INTO THURSDAY. && .AVIATION....(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1118 PM MDT THU MAY 23 2013 STRATUS CONTINUES TO STREAM NORTH ACROSS THE AREA AND CIGS WILL BE LOWERING AT BOTH KGLD AND KMCK THROUGH THE OVERNIGHT HOURS. IN ADDITION...SOUTHEASTERLY SURFACE WINDS WILL GRADUALLY INCREASE... WHICH WILL FAVOR STRATUS OVER FOG SO WILL NOT INCLUDE ANY VISIBILITY RESTRICTIONS. ON FRIDAY...CIGS WILL BE SLOW TO LIFT WITH PERSISTENT MOIST SOUTHEASTERLY FLOW. THUNDERSTORMS WILL BE POSSIBLE BY THE AFTERNOON OR EARLY EVENING AT EITHER LOCATION. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...BRB AVIATION...024
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1145 AM EDT FRI MAY 24 2013 .SYNOPSIS... DRY AND COOL WEATHER CAN BE EXPECTED FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... LIGHT SHOWERS/DRIZZLE WILL CONTINUE TO DIMINISH THROUGH THE AFTERNOON AS DRIER AIR WITH THE APPROACHING HIGH PRESSURE BEGINS TO BUILD OVERHEAD. THE BIGGEST CONCERN FOR THE NEAR TERM IS THE IMPACT CLOUD COVER WILL HAVE ON TEMPERATURES TODAY THROUGH THE OVERNIGHT AND HOW THIS WILL FURTHER IMPACT FROST/FREEZE ACROSS THE FORECAST AREA. THE MOST RECENT RUNS OF THE HRRR AND RUC SUGGEST THAT MOISTURE TRAPPED UNDER THE LOW LEVEL INVERSION WILL STRUGGLE TO MIX OUT TODAY...KEEPING CLOUD COVER OVER MUCH OF THE REGION LONGER THAN ORIGINALLY ANTICIPATED. HAVE ALREADY LOWERED HIGH TEMPERATURES A FEW DEGREES TODAY WITH THE CONTINUED COLD ADVECTION AND CLOUD COVER. DEPENDING ON WHEN THE LOWER LEVELS DRY OUT...TEMPERATURES MAY HAVE LITTLE TIME TO WARM BEFORE NIGHTFALL...LEADING TO A MORE WIDESPREAD FREEZE. OR...AS THE RUC SUGGESTS....CLOUDS COULD REMAIN OVER PORTIONS OF THE AREA THROUGH MUCH OF THE NIGHT...ELIMINATING THE FROST/FREEZE POTENTIAL. AT THIS POINT HOWEVER...FOLLOWED CLOSER TO NAM/GFS GUIDANCE AND MAINTAINED CLEARING SKIES BY TONIGHT AND THUS HAVE MADE NO CHANGES TO CURRENT PRODUCTS. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... DRY SFC HIGH PRES UNDR NW FLOW ALOFT WL MAINTAIN COLD TEMPS THROUGH THE WEEKEND. EXPECT READINGS OF 10 TO 15 DEGREES UNDR THE AVERAGES WITH FROST POTENTIAL AGAIN ON SATURDAY NGT. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... SFC HIGH PRES IS EXPECTED TO MAINTAIN DRY WEA UNTIL A WARM FRONT INCREASES PCPN CHCS FOR WEDNESDAY AND THURSDAY. INITIALLY COLD TEMPS WL MODERATE TO...AND THEN ABOVE SEASONAL LVLS AS SLY FLOW RESUMES BY MID WEEK. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... EARLY MRNG IFR AND MVFR ST AND STRATOCU CEILINGS ARE EXPECTED TO IMPROVE AS THE DAY PROGRESSES WITH DRY ADVCTN GRADUALLY INCRSG T/DP SPREADS DESPITE COLD FLOW. WIND GUSTS TO ABOUT 22 KTS CAN BE EXPECTED IN THE SHALLOW MIXING REGIME. THAT POTENTIAL WL CEASE WITH DECOUPLING THIS EVE. .OUTLOOK.../SATURDAY THROUGH TUESDAY/... HIGH PRESSURE WL MAINTAIN VFR THROUGH EARLY NXT WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR MDZ001. OH...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR OHZ039>041- 048>050-057>059-068-069. PA...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ020-021- 029-031-073-075. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ007>009- 013>016-022-023-074-076. WV...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ001>004- 012-021-022. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
702 AM EDT FRI MAY 24 2013 .AVIATION... //DISCUSSION... DEEP COLUMN TROUGHING AND COLD AIR ADVECTION HAS TEAMED TOGETHER TO ALLOW A STRATUS BLANKET TO EXPAND SOUTHWARD INTO THE CENTRAL GREAT LAKES. A STRAIGHT NORTHERLY WIND TRAJECTORY WILL MAINTAIN THE VERY AGGRESSIVE MOVEMENT. THE SHALLOW SATURATION MAKES IT EXTREMELY DIFFICULT FOR THE NWP TO CATCH UP WITH THE TRENDS...WITH THE CLOUD FORECASTING DISTILLING DOWN TO A NOWCAST OF LATEST SATELLITE IMAGERY. EXPECT A INCREASING DIABATIC HEATING TERM TO PROMOTE MIXING AND A OVC TO BKN TREND BY LATE MORNING. REGIONAL RAOBS FROM LAST EVENING RECORDED THE AMOUNT OF DRY AIR THAT IS NEARBY...SO ONCE THE DRY AIR BEGINS TO EXERT AN INFLUENCE AT ANY ONE AREA EXPECT A DECIDED MOVE TO CLEAR AND SUNNY SKIES. IN OTHER WORDS...THERE IS LOW CONFIDENCE IN TIMING. AT DTW...LINEAR INTERPOLATION OF EXISTING CLOUD DECK IS SET TO MOVE INTO THE TERMINAL PRIOR TO THE START OF THE TAF PERIOD. LOW CONFIDENCE EXISTS IN WHEN TO END THE MVFR CEILINGS...BUT A SAFE ESTIMATE WILL BE LATE MORNING WITH AN INCREASE IN DAYTIME SURFACE HEATING. //DTW THRESHOLD THREATS... * LOW CONFIDENCE THAT CEILING HEIGHTS OF LESS THAN 5000FT WILL PLAGUE THE TERMINAL THROUGH THE MORNING HOURS. && .PREV DISCUSSION...ISSUED 340 AM EDT FRI MAY 24 2013 SHORT TERM...TODAY AND TONIGHT THE WEATHER UP FOR DISCUSSION IS THE PROSPECTS FOR OVERCAST SKIES TODAY AS AN OPAQUE BLANKET OF 030-035 FT STRATUS IS AGGRESSIVELY DIVING SOUTHWARD ACROSS LAKE HURON. TRAJECTORY OF CLOUD DECK IN ADDITION TO THE ORIENTATION OF THE WESTERN EDGE ALIGNS WELL WITH THE AXIS OF MAXIMUM 925-850MB COLD AIR ADVECTION AND THE DEPRESSION OF THE LONGWAVE TROUGH AXIS. NWP DATA IS VIRTUALLY VOID OF CLOUD...A RESULT OF INADEQUATE VERTICAL RESOLUTION WITHIN THE MODELS. WHILE THE CLOUD IS COMPLETELY OPAQUE IT IS UNDOUBTEDLY A SHALLOW LAYER OF MOISTURE THAT IS LIKELY TRAPPED WITHIN THE BASE OF THE INVERSION AT/AROUND 900-890MB. RUC SOUNDINGS SHOW SATURATION AT THIS ZONE...BUT THE SOUNDING STRUCTURE ITSELF DOES NOT INSPIRE MUCH CONFIDENCE AS IT IS THE WRONG PROFILE. GIVEN THE TRUE NORTHERLY TRAJECTORY...HAVE DECIDED TO INTRODUCE OVERCAST CONDITIONS FOR MUCH OF THE CWA THROUGH THE MORNING HOURS. IT WILL BE DIFFICULT TO PINPOINT ANY WEST EDGE OF THE CLOUDS GIVEN DEGREE OF DRY AIR IMMEDIATELY TO THE WEST. PATTERN RECOGNITION SUGGESTS ENTRAINMENT AT THE EDGE SHOULD AID DIURNAL MIXING TO FORCE STRATUS TO GO BROKEN BY LATE MORNING...EVENTUALLY CLEARING OUT FOR THE AFTERNOON. LOWERED MAX TEMPERATURES FOR MANY AREAS DUE TO THE CLOUD AND STEADY COLD AIR ADVECTION. EXPECT TEMPERATURES TO EVENTUALLY REACH 60-61 DEGREES ACROSS THE SOUTH AND SAGINAW VALLEY VERY LATE IN THE DAY. OTHERWISE TEMPERATURES ARE GOING TO STRUGGLE TO REACH THE LOWER 50S IN THE THUMB. FOR TONIGHT...THE COMPACT VORT OVER NORTHERN MANITOBA WILL GET SQUEEZED WITH A ROGUE VORTICITY STREAMER OFF OF THE PACNW ANOMALY MERGING OVER THE WESTERN GREAT LAKES. THIS WILL OCCUR DOWN THE FRONT EDGE OF THE CENTRAL CONUS RIDGE...ALLOWING FOR A VERY HEALTHY AGEOSTROPHIC RESPONSE AND STRIPE OF FRONTOGENESIS VERY LATE. ANY SIGNIFICANT TEMPERATURE GRADIENT WILL RESIDE WELL WEST OF LOWER MICHIGAN WHICH IS WHERE THE PRECIPITATION RESPONSE WILL OCCUR. REGARDLESS...INCREASING CLOUDS LATE WILL ESTABLISH A FLOOR ON MINIMUM TEMPERATURES TONIGHT. LONG TERM...SATURDAY THROUGH THURSDAY THE OVERALL PATTERN ACROSS NORTH AMERICA THIS WEEKEND WILL FEATURE A QUASI OMEGA BLOCK. SHORT WAVE ENERGY NOW SHOWN ROTATING INTO NRN MANITOBA IS FORECAST TO TRACK ACROSS THE ERN GREAT LAKES AND MID ATLANTIC EARLY SATURDAY...LEADING TO DEEPENING OF AN UPPER LOW ROTATING ACROSS NEW ENGLAND. LOWER MI WILL BE LOCATED BETWEEN THIS SYSTEM AND AMPLIFYING MID LEVEL RIDGING ACROSS THE NRN PLAINS/UPPER MS VALLEY. THIS WILL PLACE THE FORECAST AREA WITHIN A STRONGLY CONFLUENT UPPER FLOW WITH PERSISTENT HIGH PRESSURE AT THE SURFACE. THE RESIDENT AIRMASS ACROSS THE GREAT LAKES WILL BE COOL AND VERY DRY. TEMPS ON SATURDAY SHOULD ONLY RISE TO THE LOW 60S OVER MUCH OF THE FORECAST AREA WITH 850MB TEMPS HOVERING AROUND +2C. THE AIRMASS WILL MODERATE DURING THE COURSE OF THE WEEKEND...WITH HIGHS EXPECTED TO BE AROUND 70 BY MEMORIAL DAY. GIVEN THE DRY AIRMASS AND LIGHT WINDS...NIGHTTIME LOWS WILL BE QUITE CHILLY THIS WEEKEND /30S AND 40S/. A SEASONALLY STRONG 140+ KNOT UPPER JET IS FORECAST DIVE INTO THE PACIFIC NORTHWEST EARLY NEXT WEEK...LEADING TO LONG WAVE TROUGH AMPLIFICATION ACROSS THE WRN US AND A BUILDING SUBTROPICAL RIDGE ACROSS THE SERN US. THIS WILL ALLOW THE MID LEVEL RIDGE TO BECOME MORE PROGRESSIVE AND PASS EAST OF LOWER MI TOWARD MIDWEEK...ALLOWING A SFC WARM FRONT TO LIFT ACROSS THE REGION FROM THE SOUTHWEST. THIS WARM FRONT WILL ADVECT A WARM...MOIST AND UNSTABLE AIRMASS INTO THE FORECAST AREA. THE GFS CONTINUES TO BRING THIS WARM FRONT THROUGH FASTER THAN THE OTHER MODEL SOLUTIONS /SUGGESTING CONVECTION AS EARLY AS MON NIGHT/. THE GFS HAS SOME OBVIOUS CONVECTIVE FEEDBACK ISSUES DUE TO POTENTIAL MCS DEVELOPMENT OVER THE PLAINS. THE GFS IS ALSO LESS AMPLIFIED WITH THE LONG WAVE TROUGH OVER THE WRN US. GIVEN THE STRENGTH OF THE POLAR JET AND POTENTIAL PHASING WITH THE SUBTROPICAL JET...THE MORE AMPLIFIED ECMWF REMAINS THE PREFERRED SOLUTION. THIS SUGGESTS THE BETTER CHANCES FOR CONVECTION WILL HOLD OFF UNTIL THE TUES NIGHT/WED TIME FRAME. DESPITE THIS UNCERTAINTY... THE OVERALL TREND NEXT WEEK WILL BE FOR WARMER AND MORE HUMID CONDITIONS WITH INCREASING CHANCES FOR THUNDERSTORMS. MARINE... UNSEASONABLE CONDITIONS ARE IN PLACE OVER THE CENTRAL GREAT LAKES TODAY AS COLD AIR ADVECTION IS ONGOING WITHIN A DEEP TROUGH AXIS. EFFICIENT NORTHERLY FLOW AND A LONG FETCH OVER THE WATERS WILL SUSTAIN HIGH WAVE ACTIVITY FROM SAGINAW BAY DOWN TO PORT HURON. RECENT WATER TEMPERATURE READINGS FROM THE BUOYS SUGGESTS THAT CONDITIONS WILL BE SOLIDLY IN THE NEUTRAL REGIME OUT OVER THE OPEN LAKE WHICH IS ATYPICAL FOR LATE MAY. IN FACT...CONDITIONS ARE UNSTABLE FOR SAGINAW BAY WITH WATER TEMPERATURE READINGS SUGGESTING LSTS ARE AT AROUND 13 TO 14 C VS AN 850MB TEMPERATURE THAT WILL BE DIPPING DOWN TO -4C BY 12Z THIS MORNING. WILL EXPAND THE ADVISORY TO INCLUDE INNER SAGINAW. CONDITIONS ARE MORE MARGINAL ON LAKE ST CLAIR AND LAKE ERIE. WILL GIVE RESPECT TO PEAK OF THE COLD AIR ADVECTION THAT WILL OCCUR THIS MORNING FOR THE SOUTHERN ZONES AND EXTEND THE SMALL CRAFT FOR THEM AS WELL. THE STABLE SURFACE ANTICYCLONE WILL BUILD INTO THE CENTRAL GREAT LAKES TONIGHT BRINGING A RETURN OF MUCH MORE FAMILIAR STABLE SEASON MARINE WEATHER. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 8 PM FRIDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...UNTIL 6 PM FRIDAY. SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL 10 AM FRIDAY. LAKE ST CLAIR... SMALL CRAFT ADVISORY...UNTIL 4 PM FRIDAY. MI WATERS OF LAKE ERIE... SMALL CRAFT ADVISORY...UNTIL 4 PM FRIDAY. && $$ AVIATION.....99 SHORT TERM...CB LONG TERM....SC MARINE.......CB YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1108 AM EDT FRI MAY 24 2013 .SYNOPSIS... MUCH COOLER AIR TURNS DRIER AND TODAY PROGRESSES. CHILLY HIGH PRESSURE TAKES CHARGE TONIGHT INTO SATURDAY. WARM FRONT IN LOWER OHIO VALLEY GRADUALLY SHIFTS NE TOWARD MEMORIAL DAY AND TUESDAY. && .NEAR TERM /THROUGH SATURDAY/... STRATOCU HANGING TOUGH ATTM ACROSS MUCH OF THE AREA...WITH AREAS ALONG AND E OF I79 CORRIDOR MAINLY OVC. BUMPED POPS UP TO LKLY FOR ANOTHER HR OR TWO ACROSS N MTNS FOR SOME SHRA. SNOWSHOE HANGING ARND 34F...HOWEVER...MOISTURE DEPTH ONLY REACHES UP TO ABOUT -3F SO KEPT THINGS LIQUID. TRIED TO DELAY SCOURING OUT OF LLVL MOISTURE PER RUC TRENDS...PRIMARILY ACROSS THE MTNS. SHOULD SEE MORE STREAKY NATURE TO FLAT STRATOCU ACROSS THE LOWLANDS WITH MORE SUNSHINE BEING OBSERVED. KNOCKED TEMPS DOWN A COUPLE DEGREES FOR THIS AFTN PER LATEST TRENDS AND LAMP GUIDANCE ESPECIALLY ACROSS THE HIGH TERRAIN. WILL BE FIGURING OUT IF FROST ADV NEEDS EXPANDING FOR AFTN PACKAGE. SFC HIGH BUILDS IN OVER NIGHT ALLOWING WINDS AT SFC TO GO CALM...BUT H925 WINDS STAY UP ARND 20 KTS. ALSO OF CONCERN IS STRATOCU TRYING TO REDEVELOP ACROSS N MTNS AND ADJ LOWLANDS TONIGHT PER RUC AND TO A LESSER DEGREE HI RES WRF MDLS. NAM KEEPS ENTIRE COLUMN DRY. PREVIOUS DISCUSSION BELOW... FINAL COLD FRONT PUSHING ACROSS CWA AT THIS TIME...AT 08Z IT WAS STRETCHING FROM CLARKSBURG SOUTH TO AROUND THE WV/VA/KY INTERSECTION. STILL SEEING SOME GUSTY WINDS ALONG AND JUST BEHIND THE FRONT...WHICH SHOULD SUBSIDE SOME EARLY THIS MORNING BEFORE PICKING BACK UP WITH MIXING TODAY. DEWPOINTS ALSO DROPPING INTO THE UPPER 30S BEHIND THE FRONT...AND EXPECT SKIES TO GRADUALLY CLEAR FROM WEST TO EAST ACROSS THE FORECAST AREA TODAY AS THE MOISTURE CONTINUES EAST AND COOL HIGH PRESSURE BEGINS TO BUILD OVER LAKE MICHIGAN. HIGHS TODAY WILL BE 10-15 DEGREES COOLER THAN YESTERDAY...MAV/MET FAIRLY CLOSE...AND SETTLED GENERALLY BETWEEN THE TWO. THE COOL HIGH PRESSURE WILL MOVE OVER FORECAST AREA TONIGHT...WITH AN UNSEASONABLY CHILLY START TO THE MEMORIAL DAY WEEKEND. MAV A BIT COOLER THAN THE MET...AND AGAIN SETTLED IN BETWEEN. THIS GIVES AROUND...TO JUST BELOW FREEZING FOR THE NORTHERN MOUNTAINS...SO OPTED FOR A FREEZE WARNING THERE. A BIT HARDER TO FIGURE OUT WHERE FROST MAY FORM DUE TO THE WARM...WET GROUND...CONTINUED BREEZE OVERNIGHT...AND RELATIVELY SHORT NIGHT TO BOOT. DECIDED ON A FROST ADVISORY ACROSS NORTHERN TWO TIERS OF COUNTIES...WITH CONTINUED MENTION IN HWO FOR THE REST OF THE CWA. DESPITE TEMPERATURES BEING COLD ENOUGH IN PARTS OF THE SOUTHERN MOUNTAINOUS COUNTIES...THINKING IT WILL REMAIN MIXY ENOUGH TO NIX ANY FROST FORMATION EVEN AT 34-36 DEGREES. AT ANY RATE...CAMPERS CELEBRATING THE UNOFFICIAL START OF SUMMER...OR THOSE WITH EARLY MORNING SOCCER OR BASEBALL WILL WAKE UP TO A CHILLY SATURDAY MORNING. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... MOST NOTABLE CHANGES MADE TOWARD MEMORIAL DAY. TIMING THE EVENTUAL NORTHEAST MOVEMENT AS A WARM FRONT...OF THE FRONTAL ZONE SETTING UP OVER THE LOWER OHIO VALLEY INTO THE TENNESSEE VALLEY IS A CHALLENGE. ONE DISTURBANCE RIDES FROM NW TO SE OVERNIGHT SATURDAY NIGHT INTO EARLY SUNDAY...BUT WILL KEEP ANY SPOTTY LIGHT RAIN TO OUR SW-S. DID HAVE MORE CLOUDS OVER OUR SOUTHERN COUNTIES IN THE FORM OF SOME PATCHY MID/HIGH CLOUDS. FURTHER NORTH...SATURDAY NIGHT WILL STILL BE MOSTLY CLEAR AND CHILLY ESPECIALLY FOR NORTHERN AND CENTRAL WEST VIRGINIA. DID INCLUDE SOME FROST IN OUR CENTRAL WV MOUNTAIN COUNTIES FOR THE EARLY DAWN SUNDAY. WILL INCREASE POPS ON MONDAY...THINKING THE WARM FRONT WILL BEGIN LIFTING NORTHEAST...AT LEAST OVER THE MIDWEST...LEAVING US VULNERABLE DOWNSTREAM. HOW ACTIVE THE WARM FRONT IS...IS ANOTHER DILEMMA. && .LONG TERM /TUESDAY THROUGH THURSDAY/... HIGH PRESSURE REMAINS IN CONTROL TO AT LEAST EARLY WEDNESDAY PROVIDING DRY WEATHER WITH A SLOW WARMING TREND. ANOTHER MID LEVEL SHORTWAVE WILL MOVE THROUGH SUNDAY NIGHT FOR LOW CHANCE FOR RAIN SHOWERS INTO MONDAY. A WARM FRONT DEVELOPS AS IT APPROACHES THE REGION ON MONDAY. AS A RESULT...THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY AND TUESDAY...MAINLY DURING THE AFTERNOON AND EVENING HOURS. FOR SATURDAY...TEMPERATURES SHOULD BE NEAR NORMAL WITH DAYTIME HIGHS IN THE 70S ACROSS LOWLANDS...WITH 60S ACROSS THE HIGHER ELEVATIONS. TEMPERATURES WILL CONTINUE TO CLIMB IN THE UPPER TO MID 80S BY THE END OF THE WEEK. LOWS WILL RANGING IN THE 60S. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... FOR THE MOST PART SHOWERS HAVE ENDED ACROSS THE FORECAST AREA...WITH MVFR CEILINGS REMAINING ACROSS THE LOWLANDS AND LOW MVFR TO IFR IN THE MOUNTAINS. CEILINGS SHOULD GRADUALLY IMPROVE TO VFR FROM WEST TO EAST TODAY. BREEZY TO GUSTY WINDS WILL CONTINUE TODAY OUT OF THE N/NW...DECREASING SOME AS THE SUN SETS TONIGHT. DRY AIR FILTERING IN SHOULD KEEP WIDESPREAD FOG CHANCES AT BAY ACROSS THE LOWLANDS TONIGHT...AND WINDS IN THE HIGHER TERRAIN SHOULD ALSO KEEP ANY DENSE FOG AWAY. WITH THAT SAID...VERY CHILLY AIR OVER RELATIVE WARM WATER IN THE RIVERS COULD PRODUCE SOME LOCALIZED MVFR FOG BY EARLY SATURDAY MORNING IN RIVER VALLEYS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY... FORECAST CONFIDENCE...HIGH. ALTERNATE SCENARIOS: TIMING OF DISSIPATION OF MVFR/IFR CEILINGS THIS MORNING MAY VARY A COUPLE OF HOURS. 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 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 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 M H M H H H H H H H H H EKN CONSISTENCY L 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 M H H H H H H H H H H AFTER 12Z SATURDAY... IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ009>011- 019-020-028>032-039-040. FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ037-038- 046-047. OH...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR OHZ066-067- 075-076. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ/30 SHORT TERM...KTB LONG TERM...ARJ AVIATION...MZ EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
855 AM EDT FRI MAY 24 2013 .SYNOPSIS... HIGH PRESSURE OF CANADIAN ORIGIN WILL BUILD INTO THE REGION TODAY PROVIDING DRY WEATHER AND CONSIDERABLY COOLER TEMPERATURES. THIS RIDGE OF HIGH PRESSURE WILL SLIDE EAST ACROSS THE REGION...OFFERING DRY CONDITIONS THROUGH THE HOLIDAY WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOW CLOUDS CONTINUE TO MOVE SOUTH ACROSS THE REGION. EXPECT THIS TO EVENTUALLY MIX OUT WITH THE AFTERNOON BECOMING MAINLY SUNNY. UPDATED TO LINGER CLOUDS A LITTLE LONGER BASED ON OBSERVATIONAL TRENDS AND LATEST RAP FORECASTS. TEMPERATURES LOOK REASONABLE BASED ON 12Z SOUNDING. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... IN NW FLOW PATTERN...SFC HIGH PRESSURE TO BUILD SE BECOMING CENTERED OVER THE REGION SATURDAY. LIGHT WINDS...AND CLEAR SKIES WILL LEAD TO A FAVORABLE RADIATIONAL COOLING SETUP. LOW TEMPERATURES TO RANGE FROM THE MID/UPR 30S FAR EAST TO THE LOWER 40S WEST. HAVE INCLUDED A MENTION OF PATCHY FROST IN THE FAR EASTERN COUNTIES. WILL CONTINUE TO HIGHLIGHT THIS POSSIBILITY OF FROST IN THE HWO PRODUCT. EXPECT MAINLY HIGH LEVEL CLOUDS TO SPILL OVER THE UP STREAM RIDGE WITH SKIES BECOMING PARTLY CLOUDY OVER THE SW SATURDAY. WAA PRECIP AND DEEPER MOISTURE EXPECTED TO REMAIN TO OUR SW. TEMPERATURES WILL BEGIN TO MODERATE WITH HIGHS STILL 8 TO 10 DEGREES BELOW NORMAL. EXPECT HIGHS TO RANGE FROM THE MID 60S NE TO THE UPR 60S SW. SATURDAY NIGHTS LOWS TO CONTINUE BELOW NORMAL RANGING FROM THE LOWER 40S NE TO ABOUT 50 SW...WHERE MORE CLOUDS ARE EXPECTED. A DISTURBANCE ROUNDING THE RIDGE WILL RESULT IN PRECIP SPILLING SE INTO THE LOWER OHIO VALLEY. IT IS NOT OUT OF THE QUESTION THAT A RAIN SHOWER SPILL INTO OUR FAR SW SUNDAY BUT WITH BEST LIFT AND MSTR TO OUR SW...WILL MAINTAIN A DRY FCST. TEMPERATURES WILL CONTINUE TO MODERATE WITH HIGHS RANGING FROM THE UPR 60S NE TO ABOUT 70 SW. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... UPPER LEVEL RIDGE IN THE CENTRAL CONUS WILL PREVAIL WITH GENERAL NORTHWEST FLOW IN THE OHIO VALLEY. GFS IS SHOWING A S/W UNDERCUTTING H5 RIDGE AND BRINGING PRECIPITATION TO THE REGION MONDAY. THIS APPEARS TO BE CONSISTENT FROM YESTERDAYS FORECAST BUT THE EUROPEAN IS ALSO CONSISTENT WITH SHOWING THIS FEATURE MUCH FURTHER SOUTHWEST AS AN ELEVATED CONVERGENT BAND AT THIS TIME. THE EUROPEAN PERMITS THIS UNDERCUTTING OF THE ESTABLISHED H5 RIDGE ON TUESDAY AND IS SHOWING A MORE TRADITIONAL WARM FRONTAL FEATURES IN THE OHIO VALLEY...ALSO SUPPORTED BY THE GFS AND CANADIAN MODEL. THIS FRONT IS VERY BROAD IN NATURE AND FORECAST IS UNCERTAIN AS TO IF THERE WILL BE ENOUGH OF A GRADIENT TO HELP FORCE SHOWERS IN A SOMEWHAT UNFAVORABLE UPPER LEVEL PATTERN...UNDERNEATH THE AXIS OF THE H5 RIDGE. UPPER LEVEL FLOW IS SHOWING A BROADENING OF THE H5 RIDGE AS IT MOVES OVER THE EASTERN THIRD OF THE COUNTRY. AM CONTINUING THE INCREASED POPS EXPECTING MID LEVEL DISTURBANCES TO UNDERCUT THE RIDGE AFTER MONDAY BUT INCREASING THROUGH THE WEEK. EXPECT A GRADUAL WARM UP EACH DAY...STARTING IN THE UPPER 60S TO AROUND 70 SUNDAY...WARMING TO NEAR 80/LOW 80S BY WED...POSSIBLY REACHING MID 80S BY THURSDAY. PM LOWS WILL BE COMFORTABLY COOL AROUND 50 MON MORNING UNDER A DRY AIRMASS AND THEN WARM PAST THE CLIMATOLOGICAL NORMS TO REACH MID 60S BY THE LATTER PART OF THE WEEK. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... CLOUDS WILL LINGER ACROSS THE TERMINALS FOR SEVERAL MORE HOURS WITH BRIEF PERIODS OF MVFR CEILINGS POSSIBLE. CLOUDS SHOULD DIMINISH AFTER 18Z. NORTH WINDS MAY BECOME GUSTY THROUGH THE DAY. WINDS WILL BECOME LIGHT AFTER 00Z SATURDAY AS HIGH CLOUDS BEGIN TO MOVE IN ON A NORTHWESTERLY FLOW ALOFT. THE LIGHT WINDS MAY ALLOW MIST TO FORM AT LUK LATE TONIGHT. CVG CAN EXPECT MID AND HIGH CLOUDS AND LIGHT EAST WINDS AFTER 12Z SATURDAY. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...AR NEAR TERM... SHORT TERM...AR LONG TERM...FRANKS AVIATION...
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
648 AM CDT FRI MAY 24 2013 .AVIATION... THE TAF FORECAST REMAINS NEBULOUS FOR TODAY BEGINNING THIS MORNING. LOW CIGS AT KCDS WILL LIKELY DISSIPATE BY LATE MORNING AND THESE CIGS ARE NOT ANTICIPATED TO AFFECT KLBB. THUNDERSTORMS MAY DEVELOP THIS AFTERNOON AT BOTH TAF SITES BUT UNCERTAINTY IS VERY HIGH SO A PROB30 MENTION WAS PLACED IN THE TAFS FOR NOW. && .PREV DISCUSSION... /ISSUED 440 AM CDT FRI MAY 24 2013/ SHORT TERM... OVERALL CHANCES OF CONVECTION WILL BE LESS FAVORABLE TODAY THAN YESTERDAY. THERE IS AN OVERALL LACK OF FORCING BOTH LARGE AND AT THE MESOSCALE LEVEL. UPPER LEVEL JET WINDS WILL UNDERGO A SIGNIFICANT WEAKENING WITH A LACK OF A FOCUSED AREA OF UPPER LEVEL DIVERGENCE. SOUTHWEST FLOW ALOFT WILL CONTINUE TO PERSIST OVER THE REGION BUT THERE ARE NO DISCERNIBLE SHORT WAVES WITH THE FLOW FOR THIS AFTERNOON. ANY WELL DEFINED LOW LEVEL BOUNDARY WILL BE WELL AWAY FROM THE REGION WITH LITTLE TO NO LOW LEVEL FOCUS RESOLVED BY MODEL SOLUTIONS. THE ONLY LOW LEVEL BOUNDARY MAY BE A LEFT OVER CONVECTIVE BOUNDARY FROM CONVECTION EARLY THIS MORNING. OTHERWISE...THE ONLY LOW LEVEL ENHANCEMENT MAY BE ALONG THE EDGE OF THE CAPROCK WITH SOUTHEASTERLY WINDS. FURTHERMORE...ISENTROPIC SURFACES WILL BE COMPOSED OF DOWNGLIDE. THERE WILL BE NO SHORTAGE OF ATMOSPHERIC INSTABILITY. INSTABILITY WILL BALLOON TO BETWEEN 2000-3000 J/KG WITH MAXIMUM VALUES OVER THE ROLLING PLAINS WHERE MOISTURE IS DEEPEST. THE RAP EVEN SHOWS AN ASTOUNDING 6000 J/KG OF SURFACE BASED CAPE BY THE AFTERNOON. SURFACE DEW POINTS ARE NOT EXPECTED TO MIX OUT AS MUCH AS THEY DID ON THURSDAY. SOUTHEAST WINDS WILL KEEP SURFACE DEW POINTS IN JUICY TERRITORY RANGING FROM UPPER 50S TO MID 60S. PRECIPITABLE WATER VALUES MAINTAIN RESPECTABLE VALUES BETWEEN 1.00 AND 1.25 INCHES. HODOGRAPHS DEPICT GOOD TURNING IN LOW LEVELS BUT WIND SPEEDS ARE FAIRLY LIGHT THROUGH MID LEVELS. THIS IS ALSO REFLECTED IN DEEP LAYER SHEAR PROGS. SHEAR VECTORS FROM 0-6KM ARE ON THE ORDER OF ONLY 25-30KT. THIS WOULD LEAD TO FAIRLY SLOW STORM MOTIONS ALLOWING FOR A DELUGE OF RAINFALL. OVERALL...CONVECTION LOOKS TO BE POORLY ORGANIZED FOR TODAY. MODELS ARE ALSO INITIATING BY LATE IN THE MORNING WHICH SEEMS EQUIVOCAL GIVEN THAT THE ATMOSPHERE WILL REMAINED CAPPED UNTIL THE EARLY AFTERNOON AMONG OTHER REASONS DISCUSSED ABOVE. LASTLY...WITH DEW POINTS NOT ANTICIPATED TO MIX OUT NEARLY AS MUCH TODAY...TEMPERATURES WILL BE SIGNIFICANTLY COOLER THIS AFTERNOON WITH MOSTLY 80S FORECAST. JDV LONG TERM... SOUTHWEST FLOW ALOFT EXPECTED TO REMAIN OVER THE SOUTH PLAINS REGION THROUGH THE MIDDLE OF THE COMING WEEK. MOISTURE FLOW WILL CONTINUE NORTHWARD WITH PRECIPITABLE WATER VALUES HOLDING IN EXCESS OF AN INCH MORE OR LESS OVER THE CENTER OF THE AREA...LESS WEST AND MORE EAST OF COURSE. THE SURFACE DRY-LINE WILL LIKELY SLOSH MOSTLY BETWEEN THE WESTERN AND EASTERN SOUTH PLAINS DURING THIS PERIOD...WHILE PRECISE LOCATIONS AT PEAK AFTERNOON HEATING PERIODS REMAINS UNCERTAIN. INSTABILITY LEVELS ALSO EXPECTED TO HOLD IN THE 1000-2000 JOULES PER KILOGRAM RANGE. WEAK EJECTING DISTURBANCES MAY PROVIDE ENOUGH LIFT AT TIMES...WHILE WEAKLY CONVERGENT LOW LEVEL FLOW ALSO COULD GENERATE LOW COVERAGE THUNDER CHANCES THROUGH TUESDAY. A STRONGER TROUGH STILL SEEMS LIKELY TO EJECT LATE WEDNESDAY AND THURSDAY...PERHAPS IN TWO OR MORE PARTS LIKE THE GFS OR AS A STRONGER TROUGH OR UPPER LOW LIKE THE ECMWF. EITHER WAY SHOULD SUPPORT MORE BACKED UPPER FLOW AND EVEN DEEPER MOISTURE WEDNESDAY AND OR THURSDAY AND MAY END UP WITH A MORE WIDESPREAD SEVERE WEATHER THREAT AS WELL. THIS IS A STRONG ENOUGH AND CONSISTENT ENOUGH SIGNAL FOR NOW TO RAISE THUNDERSTORM MENTION INTO THE CHANCE CATEGORY WEDNESDAY. TEMPERATURES SHOULD WARM A BIT ABOVE NORMAL LATE IN THE WEEKEND AND EARLY NEXT WEEK...WHILE WINDS SHOULD INCREASE BY MID-WEEK WITH THE PASSING UPPER LOW OR LOW PRESSURE TROUGH. RMCQUEEN && .PRELIMINARY POINT TEMPS/POPS... FRIONA 84 60 84 60 93 / 30 30 20 20 20 TULIA 83 62 83 60 92 / 30 30 20 20 10 PLAINVIEW 83 63 83 61 91 / 30 30 20 20 10 LEVELLAND 85 64 84 62 92 / 30 30 20 20 10 LUBBOCK 83 65 83 63 92 / 30 30 20 20 10 DENVER CITY 85 64 84 61 92 / 30 30 20 20 10 BROWNFIELD 85 65 84 62 92 / 30 30 20 20 10 CHILDRESS 83 66 85 66 93 / 30 30 20 20 10 SPUR 82 66 82 63 91 / 30 30 20 20 10 ASPERMONT 85 67 84 66 92 / 40 40 20 20 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01/99/99
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
340 PM EDT FRI MAY 24 2013 .SYNOPSIS... 19Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW AN ACTIVE UPPER LEVEL PATTERN IN PLACE OVER THE CONUS. LONGWAVE PATTERN IS DOMINATED BY DEEP TROUGHS ALONG BOTH THE PACIFIC AND ATLANTIC COASTS WHILE A LONGWAVE RIDGE AXIS BISECTS THE CONTINENT OVER THE CENTRAL PLAINS. OUR FORECAST AREA RESIDES AT THE BASE OF THE EASTERN CONUS TROUGH. A STRONG SHORTWAVE EMBEDDED WITHIN THIS TROUGH IS NOW DROPPING SOUTHEASTWARD OVER THE MID-ATLANTIC/CAROLINAS. THIS ENERGY WILL NOT ONLY ACT TO CLOSE OFF A POTENT UPPER LOW OFF THE NEW ENGLAND COAST...BUT ITS MOMENTUM WILL ALSO HELP DRIVE A LATE SEASON COLD FRONT DOWN AND THROUGH THE FLORIDA PENINSULA DURING THE NEXT 6-12 HOURS. 24/12Z KTBW SOUNDING PROFILE WAS DRY...BUT NOT UNSEASONABLY DRY...JUST YET. HOWEVER LOOKING UPSTREAM TOWARD BIRMINGHAM AND ATLANTA WE BEGIN TO SEE A MUCH DRIER AIRMASS ABOVE THE SURFACE WHICH WILL BE SETTLING SOUTHWARD AND OVER OUR HEADS FOR THE HOLIDAY WEEKEND. AT THE SURFACE...AS MENTIONED ABOVE...A LATE SEASON COLD FRONT IS READY TO ADVANCE THROUGH THE FORECAST AREA TONIGHT. THE FRONT IS CURRENTLY ANALYZED JUST SOUTH OF THE I-10 CORRIDOR WITH A DISTINCT DEWPOINT DISCONTINUITY FROM MUCH OF THE FLORIDA PENINSULA UP TO THE FL PANHANDLE AND SOUTHERN PORTION OF AL/GA. THIS MORE COMFORTABLE AIRMASS IS ON ITS WAY TO US FOR THE WEEKEND. SEEING JUST A FEW ISOLATED SHOWERS DOWN TOWARD FT. MYERS LATE THIS AFTERNOON. A FEW MORE ARE POSSIBLE TO THE SOUTH OF I-4 DURING THE NEXT FEW HOURS...HOWEVER ANY SHOWERS WILL BE SMALL AND BRIEF IN NATURE WITH VERY LOW OVERALL COVERAGE. && .SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)... TONIGHT... SURFACE FRONT SLIPS SOUTH OF THE REGION FOLLOWED QUICKLY BY STRONG CONTINENTAL HIGH PRESSURE RIDGING DOWN FROM THE NORTH. A FAVORABLE NNE DRAINAGE FLOW WILL ALLOW SOME OF OUR NORTHERN AREAS AROUND LEVY/CITRUS COUNTIES TO DROP INTO THE MID/UPPER 50S TOWARD SUNRISE ON SATURDAY...WHILE THE REMAINDER OF THE REGION DROPS DOWN INTO THE 60S. ANY ISOLATED EVENING SHOWERS OVER THE FAR SOUTHERN ZONES WILL END WITH THE FRONTAL PASSAGE SETTING UP A DRY AND PLEASANT OVERNIGHT PERIOD. SATURDAY THROUGH SUNDAY NIGHT... MID/UPPER LEVEL TROUGH AXIS WILL PUSH EAST OF THE SOUTHEAST CONUS WITH BROAD SYNOPTIC SUPPRESSION IN ITS WAKE FOR THE WEEKEND. A VERY DRY MID-LEVEL AIRMASS WITH THETA-E VALUES WELL BELOW 320K WILL BE ARRIVING FROM THE NORTH PROVIDING A QUITE HOSTILE ENVIRONMENT FOR DEEP CONVECTION. WITH THIS IN MIND...NEAR ZERO RAIN CHANCES ARE IN THE FORECAST FOR BOTH SATURDAY AND SUNDAY OVER OUR ZONES. MAY STILL BE JUST ENOUGH MOISTURE AND LOW LEVEL FORCING TO SUPPORT AN ISOLATED SHOWER OVER FAR SOUTH FLORIDA...BUT SEEMS APPARENT THAT ANY ACTIVITY WILL BE SOUTH OF OUR ZONES. LOW LEVEL FLOW WILL BE STRONG ENOUGH OUT OF THE EAST THIS WEEKEND THAT WE ARE UNLIKELY TO EVEN SEE MUCH (IF ANY) SEA-BREEZE DEVELOPMENT...ESPECIALLY ON SATURDAY. LOW LEVEL TEMPERATURES WILL COOL OFF SOMEWHAT BEHIND THE FRONT...HOWEVER DRY CONDITIONS AND EXCELLENT DIURNAL MIXING WILL COMPENSATE...AND STILL KEEP US ENJOYING SEASONABLE TEMPERATURES. UPPER 80S TO NEAR 90 WILL BE COMMON THE NEXT COUPLE OF DAY...EVEN CLOSE TO THE BEACHES AS THE EASTERLY FLOW HOLDS THE SEA-BREEZE TO THE COAST OR EVEN JUST OFFSHORE. THE IMPACT OF THE FRONT WILL BE FELT MORE AT NIGHT WITH BELOW NORMAL LOW TEMPERATURES. MAY LOCATIONS AWAY FROM THE IMMEDIATE COAST WILL LIKELY DIP INTO THE MID/UPPER 50S AROUND SUNRISE SUNDAY MORNING. ALONG THE COAST FROM TAMPA BAY SOUTHWARD LOWER TO MIDDLE 60S WILL BE MORE COMMON. SUNDAY NIGHT LOW TEMPERATURES WILL BE UP A FEW DEGREES FROM THOSE ON SATURDAY NIGHT...BUT REMAIN BELOW NORMAL FOR LATE MAY. && .LONG TERM (MONDAY THROUGH NEXT FRIDAY)... MODEL SOLUTIONS REMAIN IN GOOD AGREEMENT SHOWING HIGH PRESSURE RIDGE AXIS REMAINING NORTH OF THE FORECAST AREA THROUGH THE LONG TERM PERIODS...KEEPING AN EASTERLY BOUNDARY LAYER FLOW IN PLACE. MOISTURE WILL REMAIN LIMITED THROUGH MONDAY NIGHT...WITH RAIN FREE CONDITIONS EXPECTED. BOUNDARY LAYER MOISTURE WILL THEN SLOWLY INCREASE THROUGH THE REMAINDER OF THE WEEK...SO WILL CARRY SLIGHT CHANCE/LOW CHANCE POPS IN MOST AREAS TUESDAY THROUGH FRIDAY FOR AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS. && .AVIATION... VFR CONDITIONS WILL PREVAIL WITH FEW-SCT CLOUDS THROUGH THE AFTERNOON. THERE MAY BE SOME ISOLD TSRA NEAR PGD/FMY/RSW BUT NOT CLOSE ENOUGH TO CARRY IN THE TAF. NORTHWEST AND GUSTY WINDS DIMINISH SOME OVER NIGHT AS THEY SHIFT TO NORTH THEN NE...BECOMING ROBUST AFTER SUNRISE. && .MARINE... ROUGH BOATING CONDITIONS ARE EXPECTED AT TIMES OVER THE EASTERN GULF OF MEXICO THIS HOLIDAY WEEKEND. A COLD FRONT WILL CROSS THE FORECAST WATERS THROUGH TONIGHT ALLOWING STRONG HIGH PRESSURE TO RIDGE DOWN FROM THE NORTH IN ITS WAKE. WINDS WILL SHIFT NORTHEAST OVERNIGHT AND INCREASE TO CAUTIONARY LEVELS INTO SATURDAY MORNING. A BRIEF REDUCTION IN THE WINDS IS POSSIBLE SATURDAY AFTERNOON...BUT EXPECT EASTERLY FLOW WILL QUICKLY INCREASE ONCE AGAIN TO ADVISORY LEVELS SATURDAY EVENING AND REMAIN ELEVATED THROUGH SUNDAY MORNING. THE RIDGE POSITION WILL SUPPORT OVERNIGHT AND MORNING EASTERLY WIND SURGES THROUGH THE EARLY PORTION OF NEXT WEEK. && .FIRE WEATHER.. A DRY AIRMASS WILL ARRIVE ACROSS THE REGION FOR THE UPCOMING HOLIDAY WEEKEND. THIS DRY AIRMASS WILL ALLOW RELATIVE HUMIDITY VALUES TO DROP BELOW 35 PERCENT OVER MUCH OF THE AREA SATURDAY AFTERNOON. THE LOW RELATIVE HUMIDITY IS ANTICIPATED TO COMBINE WITH GUSTY EAST TO NORTHEAST WINDS AND ENERGY RELEASE COMPONENT VALUES OF 27 OR HIGHER TO PRODUCE CRITICAL FIRE WEATHER CONDITIONS FOR LOCATIONS CURRENTLY WITHIN THE FIRE WEATHER WATCH. DRY CONDITIONS ARE ALSO ANTICIPATED FOR SUNDAY WITH THE BEST CHANCES OF CRITICAL RELATIVE HUMIDITY VALUES BEING ALONG AND NORTH OF THE I-4 CORRIDOR. WINDS ARE NOT EXPECTED TO BE AS STRONG DURING SUNDAY AND ANY POTENTIAL RED FLAG CONDITIONS LOOK TO BE DEPENDENT ON HOW ERC VALUES FLUCTUATE DURING THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... TPA 71 90 65 88 / 10 0 0 0 FMY 69 92 66 87 / 20 10 0 0 GIF 68 89 61 87 / 10 0 0 0 SRQ 70 90 65 88 / 10 0 0 0 BKV 64 88 56 88 / 10 0 0 0 SPG 74 89 68 87 / 10 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING FOR CITRUS-DESOTO-HARDEE-HERNANDO- HILLSBOROUGH-MANATEE-PASCO-PINELLAS-POLK-SARASOTA- SUMTER. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/FIRE WEATHER...MROCZKA MARINE...MROCZKA/MCMICHAEL AVIATION/DECISION SUPPORT...RUDE LONG TERM...JELSEMA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1151 AM MDT FRI MAY 24 2013 .UPDATE... ISSUED AT 819 AM MDT FRI MAY 24 2013 MADE A FEW CHANGES TO THE FORECAST FOR TODAY. THE FIRST BEING TO INCREASE THE WINDS FOR TODAY...ESPECIALLY DURING THE MORNING. WINDS HAVE BEEN VARYING QUITE A BIT OVER THE PAST COUPLE OF HOURS. HAVE BEEN CONTEMPLATING A WIND ADVISORY FOR THE WESTERN 2/3S OF THE AREA. BIGGEST UNCERTAINTY IS WILL THE SUSTAINED WINDS REMAIN AT 30 MPH OR CONTINUE TO VARY. IN ADDITION THE WINDS MAY STRENGTHEN DURING THE AFTERNOON BEHIND THE WARM FRONT. AT THIS POINT WILL ONLY INCREASE THE SUSTAINED WINDS TO JUST UNDER 30 MPH FOR THE REST OF THE DAY FOR THE MAJORITY OF THE AREA...WHICH IS JUST UNDER WIND ADVISORY CRITERIA. IF CRITERIA IS REACHED AM CONFIDENT IT WILL BE VERY LOW END. ALSO REMOVED THE MENTION OF FOG FOR ALL BUT EAST CENTRAL COLORADO THIS MORNING. WEB CAMS AT FIRST VIEW AND GENOA BOTH SHOW VISIBILITIES OF LESS THAN A MILE. DUE TO THE RATHER SMALL AREA BEING AFFECTED AND SINCE THE FOG WILL BEGIN TO LIFT IN THE NEXT HOUR OR SO...WILL NOT BE ISSUING ANY FOG RELATED HAZARDS. DID DROP THE CHANCES FOR PRECIP. DOWN SOME THIS MORNING OVER THE EAST. MODELS DO SHOW A MINOR UPPER LEVEL SHORT WAVE TROUGH MOVING THROUGH...HOWEVER SOUNDINGS DO NOT LOOK VERY FAVORABLE FOR STORM DEVELOPMENT THIS MORNING. WILL LEAVE A SLIGHT CHANCE IN...BUT THIS MAY BE TOO MUCH FOR THE MORNING. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 434 AM MDT FRI MAY 24 2013 FORECAST PROBLEMS WILL BE NUMEROUS THROUGH THE WEEKEND. SATELLITE SHOWING A FASTER/MORE PROGRESSIVE FLOW OVER THE PACIFIC WHICH THEN TRANSITIONS TO A SLOWER AND MORE AMPLIFIED FLOW OVER NORTH AMERICA. THE RIDGE OVER THE CENTRAL PORTION OF THE COUNTRY HAS INCREASED IN AMPLITUDE OVER THE LAST 24 HOURS. UPPER LOW OVER THE PACIFIC NORTHWEST HAS MOVED LITTLE IN THE LAST 24 HOURS. FRONT THAT MOVED THROUGH YESTERDAY REMAINS DRAPED WELL SOUTH AND WEST OF THE AREA AT THIS TIME. THE SREF...NAM AND CANADIAN INITIALIZED BEST ON THE JET LEVEL WINDS OVER OUR AREA. MODELS HAVING A LITTLE TROUBLE WITH THE DETAILS AT MID LEVELS. OVERALL THE SREF AND NAM WERE DOING SLIGHTLY BETTER THAN THE GFS...CANADIAN AND CANADIAN. THE NAM LOOKED LIKE IT WAS CATCHING THE MINOR SHORTWAVE TROUGH TO OUR SOUTHWEST THE BEST. THE GFS WAS DOING SLIGHTLY BETTER THAN THE ECMWF ON THE LOW LEVEL THERMAL FIELD. THE GFS WAS TOO AGGRESSIVE WITH THE LOW LEVEL MOISTURE RETURN WITH THE NAM DOING A LITTLE BETTER. MODELS DO NOT QUITE HAVE THE BOUNDARY TO OUR SOUTH QUITE FAR ENOUGH SOUTH. THE NAM WAS DOING A LITTLE BETTER HERE. ALSO MODELS HAD QPF TOO FAR NORTH BY 06Z WITH THE GFS... CANADIAN AND THE SREF THE WORST OFFENDERS. AGAIN THE NAM WAS DOING BETTER HERE. TODAY/TONIGHT...MOST OF THE MODEL OUTPUT SHOWS A WEAK LEFT FRONT QUADRANT OVER THE AREA BEGINNING NEAR 12Z AND MAINLY AFFECTING THE SOUTHEAST HALF. A SMALL CLUSTER OF THUNDERSTORMS HAD DEVELOPED OVER NORTHEAST NEW MEXICO AND THE PANHANDLE AREA. THIS LOOKS TO BE IN RESPONSE TO SHORTWAVE TROUGH AND THE WEAK LEFT FRONT QUADRANT OF THE JET. HOWEVER THAT DISSIPATED WITH ISOLATED THUNDERSTORMS DEVELOPING OVER/NEAR THE EASTERN PORTION OF THE AREA. THE NAM FOR THE MOST PART HAS THIS AREA DEPICTED WELL...ESPECIALLY FOR THE JET. SO GOING BY THAT...WILL HAVE A SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS THROUGH MAINLY THE MORNING WITH IT POSSIBLY LINGERING INTO EARLY AFTERNOON IN THE FAR EAST. STRATUS IS MOSTLY OCCURRING OVER THE AREA AT THIS TIME WITH THE FOG CONFINED TO EASTERN COLORADO. THIS MAKES SENSE WITH THIS BEING THE MAIN AREA OF LOW LEVEL TRANSPORT OF MOISTURE AT THIS TIME. THE HRRR AND NAM INDICATE THE BEST CHANCE OF FOG OVER THE WESTERN HALF OF THE AREA. A FEW SPOTS ALSO REPORTING DRIZZLE AND SOUNDINGS WOULD INDICATE THAT WILL CONTINUE INTO THIS MORNING. SO WILL HAVE AREAS OF FOG WITH PATCHY DRIZZLE IN THE WESTERN HALF AND PATCHY FOG FURTHER EAST. SOUTHERLY WINDS INCREASE INTO THE WINDY CATEGORY. GRADIENT DEFINITELY SUPPORTS NEAR ADVISORY CRITERIA IN THE WEST BUT THERE THE 3 HOUR PRESSURE FALLS ARE NOT THAT HIGH. GLD VWP DEFINITELY WOULD SUPPORT WINDY. WILL RAISE WINDS TO NEAR ADVISORY IN THE FAR WEST. NOW FOR THE PRECIPITATION CHANCES DURING THE AFTERNOON AND NIGHT. SUBSIDENCE/DRYING OCCURS OUT EAST RATHER QUICKLY AFTER FIRST SHORTWAVE. INSTABILITY AXIS...BEST HEATING...MID/UPPER LEVEL LIFT AND SURFACE CONVERGENCE DEVELOPS NEAR OR OVER THE WESTERN PORTION OF THE AREA. SO WILL GRADUALLY RAMP UP POPS DURING THE AFTERNOON. BEST LIFT AND MOISTURE LOOK TO RESIDE OVER THE NORTH DURING THE NIGHT AND HAVE INCREASED POPS OVER THE NORTH WITH LOWER POPS FURTHER SOUTH. THUNDERSTORMS LOOK TO BE DONE BY 12Z. LOW LEVEL MOISTURE INCREASES OVER THE EASTERN HALF TO TWO THIRDS AFTER 06Z. AT THIS TIME MODELS INDICATING MOSTLY STRATUS. WILL INSERT FOG WITH THE GREATEST CHANCE IN THE FAR EAST. NOT A GOOD FEEL ON THE MAXES WITH THEM BEING DETERMINED BY THE EXTENT OF THE STRATUS AND HOW LONG IT TAKES TO BURN OFF. IT IS POSSIBLE THAT THICK CLOUD COVER WILL NOT BREAK UP UNTIL LATE MORNING. SO TRENDED THE FORECAST COOLER. SATURDAY/SATURDAY NIGHT...FOG WILL CLEAR OUT DURING THE MORNING. MODELS NOT AGREEING WHERE DRY LINE ENDS UP...WHERE THE INSTABILITY AXIS ENDS UP...WHERE THE CAP IS THE LEAST...AND SHORTWAVE DETAILS. AT THIS TIME IT LOOKS LIKE THE DRY LINE ENDS UP NEAR OR A LITTLE WEST OF THE COLORADO BORDER. ONE SHORTWAVE TROUGH EXITS THE EASTERN PORTION OF THE AREA EARLY IN THE AFTERNOON WITH ANOTHER ONE APPROACHING LATE IN THE AFTERNOON WITH THE BRUNT OF ITS LIFT COMING THROUGH DURING THE NIGHT. MODELS ARE GENERATING QPF WHERE THERE IS A STRONG CAP. AS IT LOOKS NOW THE MAIN TIME FOR PRECIPITATION WILL WAIT TO BEGIN UNTIL MID TO LATE EVENING. THE BEST CHANCE FOR THUNDERSTORMS WILL BE EAST OF THE COLORADO BORDER...AND ESPECIALLY IN THE FAR EAST. LOW LEVEL THERMAL FIELD IS MUCH WARMER THAN TODAYS. HOWEVER...IF STRATUS/FOG LAST LONGER OR THE LEE TROUGH IS STRONGER/FURTHER WEST... THE WINDS WILL BE MORE FROM AN EASTERLY DIRECTION AND NOT ALLOW FOR AS BIG A WARM UP. KEPT THE WESTERN AREAS WARMER WITH COOLER MAXES FURTHER EAST. IN REGARDS TO FIRE...THE LOWEST RHS LOOK TO BE IN COLORADO AT THIS TIME. HOWEVER...THAT IS WHERE THE LIGHTEST WIND FIELD IS. DUE TO A LOT OF UNCERTAINTY...WAS NOT CONFIDENT ENOUGH TO THROW OUT A WATCH. WILL HIGHLIGHT IN THE FIRE WEATHER FORECAST AND HWO. SUNDAY/SUNDAY NIGHT...A LOT MORE DISAGREEMENT IN DETAILS SHOW UP IN THIS PERIOD. CURRENT MODEL OUTPUT SUPPORTED THE GOING PRECIPITATION FORECAST FOR THIS PERIOD AND LEFT IT ALONE. ALSO ONLY MADE SLIGHT ADJUSTMENTS TO THE TEMPERATURE FORECAST AS WELL. P .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 235 AM MDT FRI MAY 24 2013 MEDIUM RANGE MODEL DIFFERENCES EMERGE EARLY IN THE EXTENDED PERIOD...PARTICULARLY WITH REGARD TO AMPLITUDE OF UPPER FLOW PATTERN. THE ECMWF IS MORE AMPLIFIED ON MONDAY WITH BOTH THE UPPER RIDGE POSITIONED TO OUR EAST AND ALSO THE WESTERN CONUS UPPER TROUGH. THE POSITION OF THESE FEATURES WILL PLACE OUR AREA IN SOUTHWESTERLY FLOW ALOFT WITH THE LIKELIHOOD OF WEAK EMBEDDED DIFFICULT TO TIME SHORTWAVES THAT COULD POTENTIALLY ENHANCE PRECIPITATION DEVELOPMENT. BY TUESDAY THE PATTERN AMPLIFIES FURTHER AND ECMWF CLOSES OFF AN UPPER LOW OVER THE SOUTHWEST CONUS. GFS MAINTAINS AN OPEN WAVE AND SHIFTS IT EASTWARD WITH NOTICEABLE HEIGHT FALLS OVER OUR AREA BY LATE TUESDAY AND ESPECIALLY WEDNESDAY. THE NEW 00Z ECMWF HAS TRENDED THE DIRECTION OF THE MORE PROGRESSIVE GFS AND OPENS UP THE SOUTHWEST CONUS UPPER LOW RATHER THAN KEEP IT CLOSED AND SLOWLY MOVING IT EAST AS THE 12Z ECMWF INDICATED. STILL THE ECMWF IS CONSIDERABLY SLOWER THAN THE GFS WITH THE EASTWARD PROGRESSION OF THIS TROUGH. THIS LEADS TO A LOW CONFIDENCE FORECAST NEXT WEEK. GFS WOULD FAVOR A POTENTIALLY WIDESPREAD PRECIPITATION / ORGANIZED CONVECTIVE EVENT WEDNESDAY WHILE THE ECMWF SOLUTION WOULD SUPPORT A SIMILAR SITUATION BY LATE WEDNESDAY / WEDNESDAY NIGHT INTO THURSDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1142 AM MDT FRI MAY 24 2013 MVFR TO VFR CONDITIONS ARE FORECAST FOR THE 18Z TAFS. VISIBLE SATELLITE IMAGERY SHOWS LOW CLOUDS DEPARTING THE AREA. EXPECT KMCK TO BE OUT OF THE LOW CLOUDS SHORTLY AFTER TAF ISSUANCE. AS THE CLOUDS CLEAR WINDS HAVE NOT STRENGTHENED MUCH AT ALL SO FAR...SO AM EXPECTING THIS TO CONTINUE. HOWEVER WINDS WILL REMAIN BREEZY THROUGH THE EVENING BEFORE SLOWING DURING THE OVERNIGHT HOURS. LATER THIS AFTERNOON/EARLY EVENING THUNDERSTORMS WILL DEVELOP OVER EASTERN COLORADO AND DEVELOP/PROGRESS EASTWARD. THE BEST CHANCE FOR STORMS NEAR KGLD WILL BE AROUND 0Z...WITH STORMS DISSIPATING AFTER A FEW HOURS. STRONG TO SEVERE WIND GUSTS WILL BE POSSIBLE THROUGH THE EARLY EVENING WITH ANY STORMS THAT DEVELOP. FOR KMCK THE BEST CHANCE WILL BE AROUND 6Z WITH STORMS MOVING EAST OF THE SITE BY 10Z. THERE MIGHT BE SOME FOG DEVELOPMENT AT KMCK LATE TONIGHT. HOWEVER CURRENT DATA SUGGESTS ONLY A REDUCTION TO MVFR AT BEST...SO WILL HOLD OFF PLACING A MENTION OF FOG IN FOR KMCK FOR THIS TAF ISSUANCE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...BULLER LONG TERM...BRB AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GRAY ME
530 PM EDT FRI MAY 24 2013 .SYNOPSIS... A COLD FRONT WILL PUSH OFFSHORE AND STALL THIS EVENING. LOW PRESSURE WILL DEVELOP ON THE FRONT NEAR CAPE COD AND WILL SLOWLY DRIFT NORTH THROUGH THE GULF OF MAINE SATURDAY AND SATURDAY NIGHT. LOW PRESSURE WILL ACCELERATE NORTH INTO LABRADOR ON SUNDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST SUNDAY NIGHT THROUGH MONDAY. HIGH PRESSURE WILL SHIFT OFFSHORE ON TUESDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST TUESDAY NIGHT AND WEDNESDAY AND WILL PUSH EAST OF THE REGION WEDNESDAY NIGHT. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... UPDATE... HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS...WITH THE COLD FRONT SLIPPING THROUGH THE COASTLINE AS OF 21Z. LOW PRESSURE WILL CONTINUE TO TAKE SHAPE OFF THE NEW ENG COASTLINE THEREAFTER...WITH CYCLOGENESIS OCCURRING NEAR CAPE COD THIS EVENING. LATEST HRRR MODEL PICKING UP WELL ON CONVECTIVE SEGMENTS CROSSING THE FORECAST AREA AT THIS TIME. THIS MODEL DEPICTS MORE AREAS OF RAIN MOVING THROUGH THE REGION LATE TONIGHT AFTER A BREAK IN THE ACTION LATER THIS EVENING. WILL CONTINUE TO MONITOR COLD AIR RUSHING INTO THE MTNS FROM CANADA OVERNIGHT. THERE COULD BE SOME MIXED SNOW AND RAIN OVER THE HIGHER TERRAIN FOR THIS STORM WHICH IS VERY SIMILAR TO THE MAY 26TH 1967 EVENT. HAVE ADJUSTED WINDS AND TEMPS FOR THE HIGHER TERRAIN. WINDS WILL BECOME RATHER GUSTY FOR ANY HIKERS OUT OF THE NORTH AND NORTH OVER THE NEXT COUPLE OF DAYS...WITH SOME SNOW ACROSS THE HIGH TERRAIN. PREV DISC... COLD FRONT CURRENTLY MOVING EAST THROUGH EASTERN NEW HAMPSHIRE AND NORTHWEST MAINE AND THIS BOUNDARY WILL CONTINUE TO PUSH OFF TO THE EAST THROUGH THE REMAINDER OF THE AFTERNOON. FRONT WILL STALL OFFSHORE THIS EVENING AND WILL BE THE FOCUS OF LIGHT TO MODERATE RAINFALL IN MID COAST AND CENTRAL MAINE DURING THE REMAINDER OF THE AFTERNOON INTO THIS EVENING. WILL SEE A BRIEF BREAK IN THE ACTION ACROSS NEW HAMPSHIRE DURING THE REST OF THE AFTERNOON BEFORE NEXT BATCH OF PRECIP EDGES IN FROM THE WEST. WILL TAKE SOME TIME FOR LOW PRESSURE TO GET SPUN UP OVERNIGHT SO THIS BREAK MAY TRANSLATE EASTWARD INTO WESTERN MAINE FOR THE EVENING HOURS BEFORE 850 OVER-RUNNING GETS GOING IN EARNEST ACROSS WESTERN MAINE AFTER MIDNIGHT. 12Z MODELS TRENDING FARTHER WEST WITH AXIS OF HEAVIEST PRECIP AND COMING INTO LINE WITH LAST NIGHT 00Z ECMWF. 24 HOUR QPF FOR THE MOUNTAINS AND CONNECTICUT VALLEY DOWN TO AROUND AN INCH TO 1.5 INCHES THROUGH 00Z SUN. WITH THIS IN MIND...DOESN`T APPEAR FLOODING WILL BE AN ISSUE CONSIDERING THE BREAK IN THE ACTION THIS AFTERNOON AND LONG DURATION OF THE EVENT ITSELF...SO HOLDING OFF ON ANY WATCHES AT THIS POINT IN TIME. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... RAIN WILL CONTINUE SATURDAY THROUGH SATURDAY NIGHT AS SURFACE LOW BECOMES TRAPPED UNDER UPPER LEVEL SYSTEM AND MEANDERS AROUND THE GULF OF MAINE THROUGH SUNDAY MORNING. MAY SEE SOME WET SNOW OVER THE HIGHEST TERRAIN AT SOME POINT ON SATURDAY IN FAR WESTERN ZONES BUT ENOUGH WARM AIR WRAPS AROUND THE SYSTEM THAT THIS WOULD BE FAIRLY BRIEF. BETTER CHANCE FOR THIS WOULD BE IN THE GREENS OF VERMONT AND THE DACKS. WILL BE A COLD AND BLUSTERY DAY WITH TEMPS HOLDING IN THE 40S IN MOST AREAS AND SHOWING LITTLE CHANGE SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... UPR LVL AND SFC LOWS LIFTING NE ON SUNDAY WITH STEADIER PRCP BECOMING MORE SCT IN NATURE AND LIGHTER IN INTENSITY. ANY LEFTOVER SHRA ENDING SUNDAY NGT AS THE SYSTEM MOVES INTO THE MARITIMES. MEMORIAL DAY LOOKS LIKE FAIR WX NOW WITH SYSTEM PULLING OUT FAR ENOUGH TO THE NE. STILL SOME CYCLONIC FLOW ALOFT AND SOME LEFTOVER MOISTURE THAT COULD PRODUCE SOME CLOUDINESS ESPECIALLY IN THE N/MT ZONES DUE TO UPSLOPING NW SFC WINDS. MIGHT SEE AN ISOLD SHRA IN THE N/MT ZONES OTRW NO PRCP EXPECTED ON MEMORIAL DAY. HIGH PRES AND UPR LVL RIDGE BUILD IN FOR TUESDAY INTO WEDNESDAY. THE UPR LVL RIDGE HOLDS 0N OVER THE ERN U.S. BUT A SERIES OF WEAK UPR LVL SHORT WAVE TROFS DRIVE THRU THE RIDGE FOR LATE WEDNESDAY AND THURSDAY. THIS FORMS A WRM FRONTAL BOUNDARY TO OUR S THAT LIFTS N AND WILL PROVIDE SOME CLOUDINESS AND ISOLD TO SCT SHRA FROM LATE WEDNESDAY THRU THURSDAY. THE UPR LVL RIDGE BECOMES BETTER ESTABLISHED OVER THE E COAST THURSDAY NGT AND FRIDAY AS THE SHORT WAVES EXIT THE COAST. THIS SHOULD ALLOW WRM AIR TO CONT MOVING IN FROM THE SW. STILL CAN`T RULE OUT PSBL SHRA DUE TO WRM FNT MOVING THRU. GENERALLY USED BLEND OF GFS40/NAM/MET/MAV/HPC QPF FOR PERIODS 4 AND 5 THEN GFS40, GMOS, HPC QPF, MEX MOS AND WNA4 FOR THE REST OF THE LONG TERM FCST. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... SHORT TERM...IFR/LIFR CEILINGS TONIGHT THROUGH SATURDAY NIGHT. LONG TERM /SUNDAY THROUGH WEDNESDAY/...MVFR TO PSBL IFR IN SHRA THAT WILL BE TAPERING OFF SUNDAY INTO SUNDAY NGT. MAINLY VFR MONDAY THRU TUESDAY AND MOST OF WEDNESDAY. && .MARINE... SHORT TERM...HAVE EXTENDED SCA TO GO RIGHT THROUGH SATURDAY. ALTHOUGH WINDS DROP OFF AT SOME POINT...WAVES WILL REMAIN AT LEAST IN THE 3 TO 5 FOOT RANGE...WITH GREATER SEAS OUT OVER THE OPEN WATERS. COASTAL FLOOD ADVISORY FOR MINOR SPLASH-OVER AROUND THE TIME OF HIGH TIDE. LONG TERM /SUNDAY THROUGH WEDNESDAY/...SCA WIND GUSTS AND SEAS PSBL SUNDAY THRU MOST OF SUNDAY NGT THEN HIGH PRES DROPS CONDITIONS BELOW SCA LEVELS MONDAY THRU WEDNESDAY. && .FIRE WEATHER... NO PROBLEMS NOTED. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT EDT TONIGHT FOR MEZ023>028. NH...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT EDT TONIGHT FOR NHZ014. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150>154. && $$ CANNON
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
628 PM EDT FRI MAY 24 2013 .SYNOPSIS... DRY AND COOL WEATHER CAN BE EXPECTED FOR THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY/... ADJUSTMENTS TO WINDS OVERNIGHT...JUST WEAKENED THEM A BIT FASTER. TRIED TO TIME THE DECAYING OF CLOUD DECK...WITH LOW CONFIDENCE. WESTERN EDGE OF CLOUDS ARE ERODING QUICKLY...BUT WITH CYCLONIC FLOW AND COLD AIR ALOFT...TIMING IS DIFFICULT. PREVIOUS DISCUSSION... THE UPPER LEVEL TROUGH WILL CONTINUE TO PIVOT ACROSS THE REGION THROUGH THE AFTERNOON AND EVENING AS HIGH PRESSURE TRIES TO BUILD OVERHEAD AT THE SURFACE. COLD NORTHWEST FLOW CONTINUES TO KEEP CLOUD COVER OVER MUCH OF THE FORECAST AREA THROUGH THIS AFTERNOON...WHICH IS RIGHT IN LINE WITH THE LATEST RUC FORECAST. WITH CLOUD COVER STILL IN PLACE...CONTINUED A DOWNWARD TREND IN THE HIGH TEMPERATURES FOR THE AFTERNOON...WITH PIT LIKELY TO BE VERY CLOSE TO BREAKING IT`S LOW HIGH TEMPERATURES RECORD FROM 1877. THE MOST RECENT MODEL RUNS CONTINUE TO SUGGEST THAT CLOUDS WILL EVENTUALLY DIMINISH OVER THE ENTIRE REGION...LASTING LONGEST IN THE RIDGES. HOW FAST THE CLOUDS DIMINISH WILL PLAY A BIG ROLE IN HOW QUICKLY TEMPERATURES DROP OVERNIGHT. HOWEVER...SINCE TEMPERATURES ARE ALREADY LOWER THAN ORIGINALLY FORECAST...CLEARING SKIES SHOULD ALLOW LOWS IN THE LOW TO MID 30`S TO BE REALIZED RELATIVELY QUICKLY. FOR NOW...CONTINUED THE FROST/FREEZE AS IS...ALTHOUGH SOME COUNTIES MAY NEED TO BE UPGRADED TO A FREEZE IF SKIES CLEAR SOONER AND WINDS DECOUPLE. HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY BRINGING A CLEAR DAY BUT NORTHWEST FLOW WILL KEEP TEMPERATURES 10 TO 15 BELOW SEASONAL AVERAGES. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE SHORT TERM PERIOD. TEMPERATURES WERE KEPT 5 DEGREES BELOW SEASONAL AVERAGES SUNDAY...BUT MODERATED CLOSER TO NORMAL BY MONDAY. AN APPROACHING WARM FRONT COULD BRING THE CHANCE FOR A SHOWER IN THE SOUTHERN PORTIONS OF THE FORECAST AREA LATE MONDAY BUT FOR NOW...LEFT LOW END POPS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A WARM FRONT MOVING NORTH ACROSS THE DISTRICT TUESDAY WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. AS THE WARM FRONT MOVES NORTH OF THE FORECAST AREA THURSDAY WARM AND MORE HUMID CONDITIONS WILL RETURN WITH HIGH TEMPERATURES INTO THE 80S THROUGH FRIDAY. THERE WILL BE A SLIGHT CHANCE OF DIURNAL THUNDERSTORMS THURSDAY AND FRIDAY. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... GENERAL MVFR TO VFR STRATOCU REMAINS IN PLACE THIS EVENING WITH KFKL STILL BELOW 2000 FT AT THIS HOUR. GENERAL BROKEN VFR TO MVFR CEILINGS CAN BE EXPECTED THIS EVENING. CEILINGS COULD SLOWLY LOWER AFTER SUNSET AS GUSTY WINDS DIMINISH. NORTHERLY FLOW OFF THE LAKES WILL TEND TO KEEPS SOME CLOUDINESS ACROSS THE DISTRICT INTO SATURDAY MORNING. .OUTLOOK.../SATURDAY THROUGH TUESDAY/... HIGH PRESSURE WILL MAINTAIN GENERAL VFR THROUGH MONDAY. A WARM FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS FOR TUESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR MDZ001. OH...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR OHZ039>041- 048>050-057>059-068-069. PA...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ020-021- 029-031-073-075. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ007>009- 013>016-022-023-074-076. WV...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ001>004- 012-021-022. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
326 PM EDT FRI MAY 24 2013 .SYNOPSIS... DRY AND COOL WEATHER CAN BE EXPECTED FOR THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY/... THE UPPER LEVEL TROUGH WILL CONTINUE TO PIVOT ACROSS THE REGION THROUGH THE AFTERNOON AND EVENING AS HIGH PRESSURE TRIES TO BUILD OVERHEAD AT THE SURFACE. COLD NORTHWEST FLOW CONTINUES TO KEEP CLOUD COVER OVER MUCH OF THE FORECAST AREA THROUGH THIS AFTERNOON...WHICH IS RIGHT IN LINE WITH THE LATEST RUC FORECAST. WITH CLOUD COVER STILL IN PLACE...CONTINUED A DOWNWARD TREND IN THE HIGH TEMPERATURES FOR THE AFTERNOON...WITH PIT LIKELY TO BE VERY CLOSE TO BREAKING IT`S LOW HIGH TEMPERATURES RECORD FROM 1877. THE MOST RECENT MODEL RUNS CONTINUE TO SUGGEST THAT CLOUDS WILL EVENTUALLY DIMINISH OVER THE ENTIRE REGION...LASTING LONGEST IN THE RIDGES. HOW FAST THE CLOUDS DIMINISH WILL PLAY A BIG ROLE IN HOW QUICKLY TEMPERATURES DROP OVERNIGHT. HOWEVER...SINCE TEMPERATURES ARE ALREADY LOWER THAN ORIGINALLY FORECAST...CLEARING SKIES SHOULD ALLOW LOWS IN THE LOW TO MID 30`S TO BE REALIZED RELATIVELY QUICKLY. FOR NOW...CONTINUED THE FROST/FREEZE AS IS...ALTHOUGH SOME COUNTIES MAY NEED TO BE UPGRADED TO A FREEZE IF SKIES CLEAR SOONER AND WINDS DECOUPLE. HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY BRINGING A CLEAR DAY BUT NORTHWEST FLOW WILL KEEP TEMPERATURES 10 TO 15 BELOW SEASONAL AVERAGES. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE WILL CONTINUE TO DOMINATE THROUGH THE SHORT TERM PERIOD. TEMPERATURES WERE KEPT 5 DEGREES BELOW SEASONAL AVERAGES SUNDAY...BUT MODERATED CLOSER TO NORMAL BY MONDAY. AN APPROACHING WARM FRONT COULD BRING THE CHANCE FOR A SHOWER IN THE SOUTHERN PORTIONS OF THE FORECAST AREA LATE MONDAY BUT FOR NOW...LEFT LOW END POPS. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... A WARM FRONT MOVING NORTH ACROSS THE DISTRICT TUESDAY WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. AS THE WARM FRONT MOVES NORTH OF THE FORECAST AREA THURSDAY WARM AND MORE HUMID CONDITIONS WILL RETURN WITH HIGH TEMPERATURES INTO THE 80S THROUGH FRIDAY. THERE WILL BE A SLIGHT CHANCE OF DIURNAL THUNDERSTORMS THURSDAY AND FRIDAY. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... GENERAL MVFR TO VFR STRATOCU REMAINS IN PLACE THIS EVENING WITH KFKL STILL BELOW 2000 FT AT THIS HOUR. GENERAL BROKEN VFR TO MVFR CEILINGS CAN BE EXPECTED THIS EVENING. CEILINGS COULD SLOWLY LOWER AFTER SUNSET AS GUSTY WINDS DIMINISH. NORTHERLY FLOW OFF THE LAKES WILL TEND TO KEEPS SOME CLOUDINESS ACROSS THE DISTRICT INTO SATURDAY MORNING. .OUTLOOK.../SATURDAY THROUGH TUESDAY/... HIGH PRESSURE WILL MAINTAIN GENERAL VFR THROUGH MONDAY. A WARM FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS FOR TUESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR MDZ001. OH...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR OHZ039>041- 048>050-057>059-068-069. PA...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ020-021- 029-031-073-075. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ007>009- 013>016-022-023-074-076. WV...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ001>004- 012-021-022. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1228 PM EDT FRI MAY 24 2013 .SYNOPSIS... DRY AND COOL WEATHER CAN BE EXPECTED FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... LIGHT SHOWERS/DRIZZLE WILL CONTINUE TO DIMINISH THROUGH THE AFTERNOON AS DRIER AIR WITH THE APPROACHING HIGH PRESSURE BEGINS TO BUILD OVERHEAD. THE BIGGEST CONCERN FOR THE NEAR TERM IS THE IMPACT CLOUD COVER WILL HAVE ON TEMPERATURES TODAY THROUGH THE OVERNIGHT AND HOW THIS WILL FURTHER IMPACT FROST/FREEZE ACROSS THE FORECAST AREA. THE MOST RECENT RUNS OF THE HRRR AND RUC SUGGEST THAT MOISTURE TRAPPED UNDER THE LOW LEVEL INVERSION WILL STRUGGLE TO MIX OUT TODAY...KEEPING CLOUD COVER OVER MUCH OF THE REGION LONGER THAN ORIGINALLY ANTICIPATED. HAVE ALREADY LOWERED HIGH TEMPERATURES A FEW DEGREES TODAY WITH THE CONTINUED COLD ADVECTION AND CLOUD COVER. DEPENDING ON WHEN THE LOWER LEVELS DRY OUT...TEMPERATURES MAY HAVE LITTLE TIME TO WARM BEFORE NIGHTFALL...LEADING TO A MORE WIDESPREAD FREEZE. OR...AS THE RUC SUGGESTS....CLOUDS COULD REMAIN OVER PORTIONS OF THE AREA THROUGH MUCH OF THE NIGHT...ELIMINATING THE FROST/FREEZE POTENTIAL. AT THIS POINT HOWEVER...FOLLOWED CLOSER TO NAM/GFS GUIDANCE AND MAINTAINED CLEARING SKIES BY TONIGHT AND THUS HAVE MADE NO CHANGES TO CURRENT PRODUCTS. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... DRY SFC HIGH PRES UNDR NW FLOW ALOFT WL MAINTAIN COLD TEMPS THROUGH THE WEEKEND. EXPECT READINGS OF 10 TO 15 DEGREES UNDR THE AVERAGES WITH FROST POTENTIAL AGAIN ON SATURDAY NGT. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... SFC HIGH PRES IS EXPECTED TO MAINTAIN DRY WEA UNTIL A WARM FRONT INCREASES PCPN CHCS FOR WEDNESDAY AND THURSDAY. INITIALLY COLD TEMPS WL MODERATE TO...AND THEN ABOVE SEASONAL LVLS AS SLY FLOW RESUMES BY MID WEEK. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... GENERAL MVFR TO VFR STRATOCU REMAINS IN PLACE THIS AFTERNOON WITH KMGW AND KFKL STILL BELOW 2000 FT AT THIS HOUR. CEILINGS WILL SLOWLY LIFT DURING THE AFTERNOON...WITH GENERAL BROKEN VFR CEILINGS BY THE LATE AFTERNOON HOURS. WINDS GUSTS OF 15 TO 20 KNOTS WILL PERSIST THROUGH THE AFTERNOON...BUT SHOULD DIMINISH AFTER SUNSET. STRATOCU CEILINGS MAY PERSIST AND LOWER INTO TONIGHT WITH NORTHERLY FLOW OFF THE LAKES INTO SATURDAY MORNING. .OUTLOOK.../SATURDAY THROUGH TUESDAY/... HIGH PRESSURE WL MAINTAIN VFR THROUGH EARLY NXT WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR MDZ001. OH...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR OHZ039>041- 048>050-057>059-068-069. PA...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ020-021- 029-031-073-075. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR PAZ007>009- 013>016-022-023-074-076. WV...FROST ADVISORY FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ001>004- 012-021-022. FREEZE WARNING FROM 3 AM TO 8 AM EDT SATURDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1230 PM EDT FRI MAY 24 2013 .AVIATION... //DISCUSSION... 12Z DTX SOUNDING SHOWED A REAL STRONG INVERSION AROUND 4000 FEET...WHICH ALLOWED COLD NORTHERLY FLOW OFF LAKE HURON TO SUPPORT SOLID STRATUS DECK...WHICH IS CURRENTLY IN THE PROCESS OF MIXING OUT. ONCE THIS OCCURS (MID AFTERNOON)...CLEAR SKIES SHOULD BE THE RULE INTO TONIGHT. LOW LEVELS SHOULD BE WARM ENOUGH AND FLOW BACKED TO THE WNW NOT TO SUPPORT A REPEAT PERFORMANCE OF THE LOW CLOUDS TONIGHT. THERE WILL BE SOME MID/HIGH CLOUDS ARRIVING OVERNIGHT HOWEVER...WITH JUST A BIT OF DIURNAL CU DEVELOPING TOMORROW (5000 FEET). MARGINALLY GUSTY NORTHWEST WINDS (AROUND 20 KNOTS) EARLY THIS AFTERNOON DIMINISHING...WITH LIGHT AND VARIABLE WINDS TONIGHT INTO TOMORROW. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILINGS BELOW 5000 FEET 18-20Z. && .PREV DISCUSSION...ISSUED 340 AM EDT FRI MAY 24 2013 SHORT TERM...TODAY AND TONIGHT THE WEATHER UP FOR DISCUSSION IS THE PROSPECTS FOR OVERCAST SKIES TODAY AS AN OPAQUE BLANKET OF 030-035 FT STRATUS IS AGGRESSIVELY DIVING SOUTHWARD ACROSS LAKE HURON. TRAJECTORY OF CLOUD DECK IN ADDITION TO THE ORIENTATION OF THE WESTERN EDGE ALIGNS WELL WITH THE AXIS OF MAXIMUM 925-850MB COLD AIR ADVECTION AND THE DEPRESSION OF THE LONGWAVE TROUGH AXIS. NWP DATA IS VIRTUALLY VOID OF CLOUD...A RESULT OF INADEQUATE VERTICAL RESOLUTION WITHIN THE MODELS. WHILE THE CLOUD IS COMPLETELY OPAQUE IT IS UNDOUBTEDLY A SHALLOW LAYER OF MOISTURE THAT IS LIKELY TRAPPED WITHIN THE BASE OF THE INVERSION AT/AROUND 900-890MB. RUC SOUNDINGS SHOW SATURATION AT THIS ZONE...BUT THE SOUNDING STRUCTURE ITSELF DOES NOT INSPIRE MUCH CONFIDENCE AS IT IS THE WRONG PROFILE. GIVEN THE TRUE NORTHERLY TRAJECTORY...HAVE DECIDED TO INTRODUCE OVERCAST CONDITIONS FOR MUCH OF THE CWA THROUGH THE MORNING HOURS. IT WILL BE DIFFICULT TO PINPOINT ANY WEST EDGE OF THE CLOUDS GIVEN DEGREE OF DRY AIR IMMEDIATELY TO THE WEST. PATTERN RECOGNITION SUGGESTS ENTRAINMENT AT THE EDGE SHOULD AID DIURNAL MIXING TO FORCE STRATUS TO GO BROKEN BY LATE MORNING...EVENTUALLY CLEARING OUT FOR THE AFTERNOON. LOWERED MAX TEMPERATURES FOR MANY AREAS DUE TO THE CLOUD AND STEADY COLD AIR ADVECTION. EXPECT TEMPERATURES TO EVENTUALLY REACH 60-61 DEGREES ACROSS THE SOUTH AND SAGINAW VALLEY VERY LATE IN THE DAY. OTHERWISE TEMPERATURES ARE GOING TO STRUGGLE TO REACH THE LOWER 50S IN THE THUMB. FOR TONIGHT...THE COMPACT VORT OVER NORTHERN MANITOBA WILL GET SQUEEZED WITH A ROGUE VORTICITY STREAMER OFF OF THE PACNW ANOMALY MERGING OVER THE WESTERN GREAT LAKES. THIS WILL OCCUR DOWN THE FRONT EDGE OF THE CENTRAL CONUS RIDGE...ALLOWING FOR A VERY HEALTHY AGEOSTROPHIC RESPONSE AND STRIPE OF FRONTOGENESIS VERY LATE. ANY SIGNIFICANT TEMPERATURE GRADIENT WILL RESIDE WELL WEST OF LOWER MICHIGAN WHICH IS WHERE THE PRECIPITATION RESPONSE WILL OCCUR. REGARDLESS...INCREASING CLOUDS LATE WILL ESTABLISH A FLOOR ON MINIMUM TEMPERATURES TONIGHT. LONG TERM...SATURDAY THROUGH THURSDAY THE OVERALL PATTERN ACROSS NORTH AMERICA THIS WEEKEND WILL FEATURE A QUASI OMEGA BLOCK. SHORT WAVE ENERGY NOW SHOWN ROTATING INTO NRN MANITOBA IS FORECAST TO TRACK ACROSS THE ERN GREAT LAKES AND MID ATLANTIC EARLY SATURDAY...LEADING TO DEEPENING OF AN UPPER LOW ROTATING ACROSS NEW ENGLAND. LOWER MI WILL BE LOCATED BETWEEN THIS SYSTEM AND AMPLIFYING MID LEVEL RIDGING ACROSS THE NRN PLAINS/UPPER MS VALLEY. THIS WILL PLACE THE FORECAST AREA WITHIN A STRONGLY CONFLUENT UPPER FLOW WITH PERSISTENT HIGH PRESSURE AT THE SURFACE. THE RESIDENT AIRMASS ACROSS THE GREAT LAKES WILL BE COOL AND VERY DRY. TEMPS ON SATURDAY SHOULD ONLY RISE TO THE LOW 60S OVER MUCH OF THE FORECAST AREA WITH 850MB TEMPS HOVERING AROUND +2C. THE AIRMASS WILL MODERATE DURING THE COURSE OF THE WEEKEND...WITH HIGHS EXPECTED TO BE AROUND 70 BY MEMORIAL DAY. GIVEN THE DRY AIRMASS AND LIGHT WINDS...NIGHTTIME LOWS WILL BE QUITE CHILLY THIS WEEKEND /30S AND 40S/. A SEASONALLY STRONG 140+ KNOT UPPER JET IS FORECAST DIVE INTO THE PACIFIC NORTHWEST EARLY NEXT WEEK...LEADING TO LONG WAVE TROUGH AMPLIFICATION ACROSS THE WRN US AND A BUILDING SUBTROPICAL RIDGE ACROSS THE SERN US. THIS WILL ALLOW THE MID LEVEL RIDGE TO BECOME MORE PROGRESSIVE AND PASS EAST OF LOWER MI TOWARD MIDWEEK...ALLOWING A SFC WARM FRONT TO LIFT ACROSS THE REGION FROM THE SOUTHWEST. THIS WARM FRONT WILL ADVECT A WARM...MOIST AND UNSTABLE AIRMASS INTO THE FORECAST AREA. THE GFS CONTINUES TO BRING THIS WARM FRONT THROUGH FASTER THAN THE OTHER MODEL SOLUTIONS /SUGGESTING CONVECTION AS EARLY AS MON NIGHT/. THE GFS HAS SOME OBVIOUS CONVECTIVE FEEDBACK ISSUES DUE TO POTENTIAL MCS DEVELOPMENT OVER THE PLAINS. THE GFS IS ALSO LESS AMPLIFIED WITH THE LONG WAVE TROUGH OVER THE WRN US. GIVEN THE STRENGTH OF THE POLAR JET AND POTENTIAL PHASING WITH THE SUBTROPICAL JET...THE MORE AMPLIFIED ECMWF REMAINS THE PREFERRED SOLUTION. THIS SUGGESTS THE BETTER CHANCES FOR CONVECTION WILL HOLD OFF UNTIL THE TUES NIGHT/WED TIME FRAME. DESPITE THIS UNCERTAINTY... THE OVERALL TREND NEXT WEEK WILL BE FOR WARMER AND MORE HUMID CONDITIONS WITH INCREASING CHANCES FOR THUNDERSTORMS. MARINE... UNSEASONABLE CONDITIONS ARE IN PLACE OVER THE CENTRAL GREAT LAKES TODAY AS COLD AIR ADVECTION IS ONGOING WITHIN A DEEP TROUGH AXIS. EFFICIENT NORTHERLY FLOW AND A LONG FETCH OVER THE WATERS WILL SUSTAIN HIGH WAVE ACTIVITY FROM SAGINAW BAY DOWN TO PORT HURON. RECENT WATER TEMPERATURE READINGS FROM THE BUOYS SUGGESTS THAT CONDITIONS WILL BE SOLIDLY IN THE NEUTRAL REGIME OUT OVER THE OPEN LAKE WHICH IS ATYPICAL FOR LATE MAY. IN FACT...CONDITIONS ARE UNSTABLE FOR SAGINAW BAY WITH WATER TEMPERATURE READINGS SUGGESTING LSTS ARE AT AROUND 13 TO 14 C VS AN 850MB TEMPERATURE THAT WILL BE DIPPING DOWN TO -4C BY 12Z THIS MORNING. WILL EXPAND THE ADVISORY TO INCLUDE INNER SAGINAW. CONDITIONS ARE MORE MARGINAL ON LAKE ST CLAIR AND LAKE ERIE. WILL GIVE RESPECT TO PEAK OF THE COLD AIR ADVECTION THAT WILL OCCUR THIS MORNING FOR THE SOUTHERN ZONES AND EXTEND THE SMALL CRAFT FOR THEM AS WELL. THE STABLE SURFACE ANTICYCLONE WILL BUILD INTO THE CENTRAL GREAT LAKES TONIGHT BRINGING A RETURN OF MUCH MORE FAMILIAR STABLE SEASON MARINE WEATHER. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 8 PM FRIDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...UNTIL 6 PM FRIDAY. LAKE ST CLAIR... SMALL CRAFT ADVISORY...UNTIL 4 PM FRIDAY. MI WATERS OF LAKE ERIE... SMALL CRAFT ADVISORY...UNTIL 4 PM FRIDAY. && $$ AVIATION.....SF SHORT TERM...CB LONG TERM....SC MARINE.......CB YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
629 PM EDT FRI MAY 24 2013 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE WESTERN GREAT LAKES WILL MOVE LITTLE THROUGH THE WEEKEND...THEN SLIDE TO THE EAST COAST MONDAY AND TUESDAY. A WARM FRONT WILL DEVELOP OVER THE MISSISSIPPI VALLEY BY MONDAY AND LIFT NORTH ACROSS THE AREA ON TUESDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... MADE MINOR ADJUSTMENTS TO THE HOURLY TEMPERATURES AND SKY COVER THIS EVENING FOR THE EARLY EVENING UPDATE. CALLED IT "CLEARING" FOR THE NE OH/NW PA COUNTIES...OTHERWISE NO CHANGES TO THE CURRENT FORECAST. EARLIER DISCUSSION... GIVEN THE TIME OF YEAR AND IMPACT AND HAVE GONE WITH FROST AND FREEZE HEADLINES FOR THE ENTIRE AREA. IT APPEARS THAT CLEARING WILL RAPIDLY OCCUR THIS EVENING. WINDS SHOULD ALSO LESSEN. IF SPEEDS STAY MORE THAN 5 OR 6 MPH OVERNIGHT FREEZING TEMPS WILL BE HARD TO ACHIEVE. IF FREEZING TEMPS DO OCCUR IT WILL BE ONE OF THE LATEST FREEZES EVER AT ALL OF THE CLIMATE SITES. TEMPS REMAIN IN THE 40S MOST AREAS AND SHOULD DROP QUICKLY AFTER SUNSET. SOME INDICATION THAT HIGH CLOUDS COULD SPILL INTO WESTERN AREAS LATE TONIGHT. GIVEN THE STRENGTH OF THE HIGH THIS COULD BE A LITTLE OVERDONE SO HAVE TAKEN THE FROST HEADLINE ALL THE WAY TO KTOL AND KFDY. LATEST HRRR HAS SURFACE TEMPS TO 34 DEGREES BY 04Z OVER MOST OF INLAND NE OH AND NW PA. IF THAT OCCURS FROST IS LIKELY BY EARLY MORNING. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/... DRY HIGH PRESSURE WILL DOMINATE THROUGH THE HOLIDAY WEEKEND. THE AREA WILL REMAIN COOL WITH ONLY VERY SLOWLY MODERATING TEMPERATURES. WILL LIKELY NEED MORE FROST HEADLINES SATURDAY NIGHT IN THE EAST. EXPECT TEMPS TO STRUGGLE TO GET ABOVE 60 ON SATURDAY AND OUT OF THE LOWER AND MIDDLE 60S ON SUNDAY. TEMPERATURE MAY GET TO 70 ON MONDAY BUT THAT WILL STILL BELOW NORMAL. MODELS HAVE BEEN SHOWING A SYSTEM MOVING OUT OF THE PLAINS MONDAY. A WARM FRONT FROM THIS SYSTEM WILL BEGIN TO IMPACT THE AREA MONDAY NIGHT AND HAVE PUT SOME WARM AIR ADVECTION PRECIP IN THE WEST MONDAY NIGHT. THINK DRY WEATHER WILL PREVAIL IN THE EAST TILL AFTER THE SHORT TERM PERIOD. GIVEN A LOOK AT UPSTREAM SATELLITE TODAY SKIES SHOULD BE ALMOST COMPLETELY CLEAR ON SATURDAY WITH JUST SOME HIGH CLOUDS THE REMAINDER OF THE WEEKEND. HAVE TRENDED TO COOL SIDE OF GUIDANCE THROUGH THE PERIOD. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE TUESDAY AND TUESDAY NIGHT AS A WARM FRONT LIFTS THROUGH. IN THE WARM AIR MASS WEDNESDAY THROUGH FRIDAY THERE COULD BE SOME POP UP SHOWERS AND THUNDERSTORMS...CONTINUING THE 20 POPS. OTHERWISE A WARMING TREND WITH HIGHS ABOVE NORMAL. USED A BLEND OF GUIDANCE...ESPECIALLY HPC. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... HIGH PRESSURE IS BUILDING IN THROUGH TONIGHT. THE CLOUDS WILL SLOWLY DECREASE AND THE CEILINGS ARE RISING AND WILL BE VFR BY MID AFTERNOON. SKIES SHOULD BE CLEAR BY DARK. NOT EXPECTING MUCH FOG AT THE TAF SITES BUT SOME MVFR FOG MAY OCCUR AT FAVORED LOCATIONS. VFR SATURDAY WITH SOME CIRRUS AND A LIGHT NORTHWEST WIND. .OUTLOOK...NON VFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY NIGHT THROUGH TUESDAY. && .MARINE... DROPPING THE SMALL CRAFT ADVISORY ON THE EXTREME WEST END OF THE LAKE AS THE HIGH IS BUILDING IN. OTHERWISE NO CHANGES TO THE HEADLINES. THE ONLY CONCERN IS THAT THE WAVES COULD BE NEAR SMALL CRAFT ADVISORY CRITERIA SATURDAY AFTERNOON IN THE NORTHWEST FLOW...THIS WILL HAVE TO BE MONITORED. OTHERWISE NOT EXPECTING CONDITIONS TO MEET SMALL CRAFT ADVISORY CONDITIONS ON THE LAKE IN A MAINLY SOUTHWEST FLOW. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR OHZ003-006>012-017>019-027-028-036-089. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR OHZ013-014-020>023-029>033-037-038-047. PA...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR PAZ001. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR PAZ002-003. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ146>149. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LEZ144-145. && $$ SYNOPSIS...KOSARIK/KUBINA NEAR TERM...KOSARIK/KUBINA SHORT TERM...KUBINA LONG TERM...KIELTYKA AVIATION...KIELTYKA MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
423 PM EDT FRI MAY 24 2013 .SYNOPSIS... CHILLY HIGH PRESSURE TAKES CHARGE TONIGHT INTO SATURDAY. WARM FRONT LIFT NORTH INTO THE OHIO VALLEY AND WEST VIRGINIA EARLY TUESDAY. A WARMING TREND EXPECTED MEMORIAL DAY THROUGH NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... VERY TOUGH FCST TONIGHT REGARDING FROST/FREEZE POTENTIAL. DWPTS CURRENTLY STRADDLING THE MARGINAL THRESHOLD FOR FROST TONIGHT GIVEN AFTN MIXING. NOT SURE IF THESE GO LWR NEXT FEW HRS BEFORE RECOVERING THIS EVE. GUIDANCE FOR METRO AREAS IN THE LOWLANDS RUN 32 TO 40F FROM KHTS TO KCRW. H925 WINDS STAY UP ARND 20 KTS OVERNIGHT AS SFC HIGH BUILDS IN TO ALLOW WINDS AT THE GROUND TO TRY TO GO CALM. ALL OF THIS COMPLICATES MATTERS FOR EXPANDING FROST ADV. HOWEVER...GIVEN TIME OF YEAR AND FACT THAT MOST FOLKS HAVE SOME OF THEIR VEGGIES IN THE GROUND ALONG WITH ANNUAL PLANT INVESTMENTS...FELT PRUDENT TO LEAN A LITTLE LIBERAL AND EXPAND TO ENCOMPASS REST OF CWA SAVE FOR S COAL FIELDS TO SW VA. OUTLYING AREAS WILL SEE BEST SHOT OF FROST. HEADLINE SHOULD GARNER MORE ATTENTION FOR FOLKS TO TAKE PRECAUTIONS TO BE ON SAFE SIDE. ALSO EXPANDED FRZ WARNING TO RALEIGH BASED ON GUIDANCE RANGING FROM 28F TO 33F. THEY WILL HAVE GET UNDER INVERSION THOUGH GIVEN H925 WINDS OFF MDLS OVERNIGHT. OTHER CONCERN IS STRATUS OVERNIGHT ACROSS THE N. NAM HAS BEEN WAY TOO FAST IN ERADICATING THE LLVL MOISTURE VS RUC WHICH HAS BEEN PRETTY STEADY. RUC SHOWS CLDS LIFTING AND SCT THIS EVE ACROSS THE N BEFORE REDEVELOPING IN N MTNS BY 06Z. NAM KEEPS ENTIRE COLUMN DRY BUT HAS NOT HANDLED TDY WELL AT ALL. SO WILL LEAN TOWARD RUC AND REDEVELOP SOME STRATUS IN N MTNS LATE TONIGHT. THIS MAY KEEP TEMPS UP TONIGHT ESPECIALLY IN VALLEYS...BUT STILL FEEL AOB FRZ TEMPS WILL BE REALIZED. UPR TROF AXIS SHIFTS TO E COAST ON SAT WITH SOME RECOVERY IN TEMPS COMPARED TO TDY. INHERITED TEMPS LOOKED GOOD AND ONLY NEEDED TWEAKING SOME...MAINLY ACROSS THE N. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... MADE MODIFICATIONS TO THE SHORT TERM FORECAST AS FOLLOWS: HIGH PRESSURE WILL BE IN CONTROL THROUGH THE WEEKEND...KEEPING DRY CONDITIONS AREAWIDE. MODELS SHOW A MID LEVEL SHORTWAVE...EVIDENT IN H5 CHARTS...UNDER NORTHWEST FLOW ALOFT...MOVING ACROSS SOUTHERN OH...SOUTHEAST INTO NORTHWEST KY. REMOVED ANY POPS FOR THE WEEKEND AS MOISTURE LOOKS VERY LIMITED OVER WV. IN FACT...THERE COULD BE SOME CLEARING SATURDAY NIGHT INTO SUNDAY MORNING...KEEPING TEMPERATURES AT OR JUST BELOW FREEZING OVER POCAHONTAS AND RANDOLPH COUNTIES. INCLUDED PATCHY FROST OVER NORTHEAST MOUNTAINS. HIGH PRESSURE MOVES EAST OVER THE MID ATLANTIC STATES KEEPING INFLUENCE OVER WV FOR A DRY SUNDAY THROUGH MONDAY NIGHT. MINOR CHANGES TO TEMPERATURES THROUGH THE PERIOD...PERHAPS A COUPLE DEGREES LOWER CLOSER TO THE COOLER MET. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... ANOTHER SHORTWAVE UNDER NORTHWEST FLOW ALOFT PASSES ACROSS SOUTHEAST OH AND WV MONDAY AND TUESDAY. AT THE SAME TIME...A WARM FRONT LIFTS NORTH INTO SOUTHERN OH...ACROSS WV AND VA ORIENTED WEST TO EAST BY 12Z TUESDAY. THESE TWO FEATURES WILL BE CAPABLE TO PRODUCE SHOWERS AND STORMS LATE MONDAY INTO TUESDAY AS THE WARM FRONT MOVES NORTH OF THE AREA BY EARLY WEDNESDAY. INCREASED POPS TO CHANCE INCLUDING THUNDER IN WEATHER GRIDS ACCORDINGLY. HIGH PRESSURE TAKES CONTROL BY EARLY WEDNESDAY PROVIDING DRY WEATHER WITH A SLOW WARMING TREND THROUGH THE REST OF THE WEEK. TWEAKED COUPLE OF DEGREES DOWN FROM HPC GUIDANCE IN THE EXTENDED PERIODS. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... STRATOCU SHOULD BEGIN TO DISSIPATE FROM W TO E BY THIS EVE. EXCEPTION BEING N LOWLANDS AND ESPECIALLY N MTNS WHERE MVFR STRATUS MAY REDEVELOP AFTER 06Z. HAVE KEKN WITH SOME BKN MVFR BASES AS A RESULT. OTHERWISE SFC HIGH WILL BUILD IN AFTER 09Z WITH SLACKENING WINDS THIS EVE WITH LOSS OF SUN. NW FLOW ALOFT TONIGHT AND TOMORROW. MAY SEE SOME FG HUG WARMER RVRS WHICH MAY AFFECT RVR TERMINALS. HAVE SOME MVFR VSBY ATTM WITH BL WINDS HANGING ONTO A BIT OF A PUFF. VFR CONDITIONS RETURN FOR ALL TOMORROW WITH JUST SOME PASSING MID CLDS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: EXTENT OF FG OVERNIGHT IN QUESTION. STRATUS MAY NOT REDEVELOP ACROSS THE MTNS AS FCST. 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 M M 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 M M EKN CONSISTENCY M M M M M M M M M M M 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 M M M M AFTER 18Z SATURDAY... IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ005>011- 013>020-026>032-039-040. FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ035>038- 046-047. OH...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR OHZ066-067- 075-076-083>087. KY...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR KYZ101>103- 105. VA...NONE. && $$ SYNOPSIS...ARJ/30 NEAR TERM...30 SHORT TERM...ARJ LONG TERM...ARJ AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
355 PM EDT FRI MAY 24 2013 .SYNOPSIS... CHILLY HIGH PRESSURE TAKES CHARGE TONIGHT INTO SATURDAY. WARM FRONT IN LOWER OHIO VALLEY GRADUALLY SHIFTS NE TOWARD MEMORIAL DAY AND TUESDAY. && .NEAR TERM /THROUGH SATURDAY NIGHT/... VERY TOUGH FCST TONIGHT REGARDING FROST/FREEZE POTENTIAL. DWPTS CURRENTLY STRADDLING THE MARGINAL THRESHOLD FOR FROST TONIGHT GIVEN AFTN MIXING. NOT SURE IF THESE GO LWR NEXT FEW HRS BEFORE RECOVERING THIS EVE. GUIDANCE FOR METRO AREAS IN THE LOWLANDS RUN 32 TO 40F FROM KHTS TO KCRW. H925 WINDS STAY UP ARND 20 KTS OVERNIGHT AS SFC HIGH BUILDS IN TO ALLOW WINDS AT THE GROUND TO TRY TO GO CALM. ALL OF THIS COMPLICATES MATTERS FOR EXPANDING FROST ADV. HOWEVER...GIVEN TIME OF YEAR AND FACT THAT MOST FOLKS HAVE SOME OF THEIR VEGGIES IN THE GROUND ALONG WITH ANNUAL PLANT INVESTMENTS...FELT PRUDENT TO LEAN A LITTLE LIBERAL AND EXPAND TO ENCOMPASS REST OF CWA SAVE FOR S COAL FIELDS TO SW VA. OUTLYING AREAS WILL SEE BEST SHOT OF FROST. HEADLINE SHOULD GARNER MORE ATTENTION FOR FOLKS TO TAKE PRECAUTIONS TO BE ON SAFE SIDE. ALSO EXPANDED FRZ WARNING TO RALEIGH BASED ON GUIDANCE RANGING FROM 28F TO 33F. THEY WILL HAVE GET UNDER INVERSION THOUGH GIVEN H925 WINDS OFF MDLS OVERNIGHT. OTHER CONCERN IS STRATUS OVERNIGHT ACROSS THE N. NAM HAS BEEN WAY TOO FAST IN ERADICATING THE LLVL MOISTURE VS RUC WHICH HAS BEEN PRETTY STEADY. RUC SHOWS CLDS LIFTING AND SCT THIS EVE ACROSS THE N BEFORE REDEVELOPING IN N MTNS BY 06Z. NAM KEEPS ENTIRE COLUMN DRY BUT HAS NOT HANDLED TDY WELL AT ALL. SO WILL LEAN TOWARD RUC AND REDEVELOP SOME STRATUS IN N MTNS LATE TONIGHT. THIS MAY KEEP TEMPS UP TONIGHT ESPECIALLY IN VALLEYS...BUT STILL FEEL AOB FRZ TEMPS WILL BE REALIZED. UPR TROF AXIS SHIFTS TO E COAST ON SAT WITH SOME RECOVERY IN TEMPS COMPARED TO TDY. INHERITED TEMPS LOOKED GOOD AND ONLY NEEDED TWEAKING SOME...MAINLY ACROSS THE N. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... MOST NOTABLE CHANGES MADE TOWARD MEMORIAL DAY. TIMING THE EVENTUAL NORTHEAST MOVEMENT AS A WARM FRONT...OF THE FRONTAL ZONE SETTING UP OVER THE LOWER OHIO VALLEY INTO THE TENNESSEE VALLEY IS A CHALLENGE. ONE DISTURBANCE RIDES FROM NW TO SE OVERNIGHT SATURDAY NIGHT INTO EARLY SUNDAY...BUT WILL KEEP ANY SPOTTY LIGHT RAIN TO OUR SW-S. DID HAVE MORE CLOUDS OVER OUR SOUTHERN COUNTIES IN THE FORM OF SOME PATCHY MID/HIGH CLOUDS. FURTHER NORTH...SATURDAY NIGHT WILL STILL BE MOSTLY CLEAR AND CHILLY ESPECIALLY FOR NORTHERN AND CENTRAL WEST VIRGINIA. DID INCLUDE SOME FROST IN OUR CENTRAL WV MOUNTAIN COUNTIES FOR THE EARLY DAWN SUNDAY. WILL INCREASE POPS ON MONDAY...THINKING THE WARM FRONT WILL BEGIN LIFTING NORTHEAST...AT LEAST OVER THE MIDWEST...LEAVING US VULNERABLE DOWNSTREAM. HOW ACTIVE THE WARM FRONT IS...IS ANOTHER DILEMMA. && .LONG TERM /TUESDAY THROUGH FRIDAY/... HIGH PRESSURE REMAINS IN CONTROL TO AT LEAST EARLY WEDNESDAY PROVIDING DRY WEATHER WITH A SLOW WARMING TREND. ANOTHER MID LEVEL SHORTWAVE WILL MOVE THROUGH SUNDAY NIGHT FOR LOW CHANCE FOR RAIN SHOWERS INTO MONDAY. A WARM FRONT DEVELOPS AS IT APPROACHES THE REGION ON MONDAY. AS A RESULT...THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY AND TUESDAY...MAINLY DURING THE AFTERNOON AND EVENING HOURS. FOR SATURDAY...TEMPERATURES SHOULD BE NEAR NORMAL WITH DAYTIME HIGHS IN THE 70S ACROSS LOWLANDS...WITH 60S ACROSS THE HIGHER ELEVATIONS. TEMPERATURES WILL CONTINUE TO CLIMB IN THE UPPER TO MID 80S BY THE END OF THE WEEK. LOWS WILL RANGING IN THE 60S. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... STRATOCU SHOULD BEGIN TO DISSIPATE FROM W TO E BY THIS EVE. EXCEPTIONG BEING N LOWLANDS AND ESPECIALLY N MTNS WHERE MVFR STRATUS MAY REDEVELOP AFTER 06Z. HAVE KEKN WITH SOME BKN MVFR BASES AS A RESULT. OTHERWISE SFC HIGH WILL BUILD IN AFTER 09Z WITH SLACKENING WINDS THIS EVE WITH LOSS OF SUN. NW FLOW ALOFT TONIGHT AND TOMORROW. MAY SEE SOME FG HUG WARMER RVRS WHICH MAY AFFECT RVR TERMINALS. HAVE SOME MVFR VSBY ATTM WITH BL WINDS HANGING ONTO A BIT OF A PUFF. VFR CONDITIONS RETURN FOR ALL TOMORROW WITH JUST SOME PASSING MID CLDS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: EXTENT OF FG OVERNIGHT IN QUESTION. STRATUS MAY NOT REDEVELOP ACROSS THE MTNS AS FCST. 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 M M 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 M M EKN CONSISTENCY M M M M M M M M M M M 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 M M M M AFTER 18Z SATURDAY... IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ005>011- 013>020-026>032-039-040. FREEZE WARNING FROM 2 AM TO 8 AM EDT SATURDAY FOR WVZ035>038- 046-047. OH...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR OHZ066-067- 075-076-083>087. KY...FROST ADVISORY FROM 2 AM TO 8 AM EDT SATURDAY FOR KYZ101>103- 105. VA...NONE. && $$ SYNOPSIS...ARJ/30 NEAR TERM...30 SHORT TERM...KTB LONG TERM...ARJ AVIATION...30
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
321 PM EDT FRI MAY 24 2013 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE GREAT LAKES WILL MOVE LITTLE THROUGH THE WEEKEND. THE HIGH WILL MOVE OFF TO THE NORTHEAST MONDAY AND TUESDAY. THIS WILL ALLOW A WARM FRONT TO LIFT NORTH INTO THE REGION ON TUESDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... GIVEN THE TIME OF YEAR AND IMPACT AND HAVE GONE WITH FROST AND FREEZE HEADLINES FOR THE ENTIRE AREA. IT APPEARS THAT CLEARING WILL RAPIDLY OCCUR THIS EVENING. WINDS SHOULD ALSO LESSEN. IF SPEEDS STAY MORE THAN 5 OR 6 MPH OVERNIGHT FREEZING TEMPS WILL BE HARD TO ACHIEVE. IF FREEZING TEMPS DO OCCUR IT WILL BE ONE OF THE LATEST FREEZES EVER AT ALL OF THE CLIMATE SITES. TEMPS REMAIN IN THE 40S MOST AREAS AND SHOULD DROP QUICKLY AFTER SUNSET. SOME INDICATION THAT HIGH CLOUDS COULD SPILL INTO WESTERN AREAS LATE TONIGHT. GIVEN THE STRENGTH OF THE HIGH THIS COULD BE A LITTLE OVERDONE SO HAVE TAKEN THE FROST HEADLINE ALL THE WAY TO KTOL AND KFDY. LATEST HRRR HAS SURFACE TEMPS TO 34 DEGREES BY 04Z OVER MOST OF INLAND NE OH AND NW PA. IF THAT OCCURS FROST IS LIKELY BY EARLY MORNING. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/... DRY HIGH PRESSURE WILL DOMINATE THROUGH THE HOLIDAY WEEKEND. THE AREA WILL REMAIN COOL WITH ONLY VERY SLOWLY MODERATING TEMPERATURES. WILL LIKELY NEED MORE FROST HEADLINES SATURDAY NIGHT IN THE EAST. EXPECT TEMPS TO STRUGGLE TO GET ABOVE 60 ON SATURDAY AND OUT OF THE LOWER AND MIDDLE 60S ON SUNDAY. TEMPERATURE MAY GET TO 70 ON MONDAY BUT THAT WILL STILL BELOW NORMAL. MODELS HAVE BEEN SHOWING A SYSTEM MOVING OUT OF THE PLAINS MONDAY. A WARM FRONT FROM THIS SYSTEM WILL BEGIN TO IMPACT THE AREA MONDAY NIGHT AND HAVE PUT SOME WARM AIR ADVECTION PRECIP IN THE WEST MONDAY NIGHT. THINK DRY WEATHER WILL PREVAIL IN THE EAST TILL AFTER THE SHORT TERM PERIOD. GIVEN A LOOK AT UPSTREAM SATELLITE TODAY SKIES SHOULD BE ALMOST COMPLETELY CLEAR ON SATURDAY WITH JUST SOME HIGH CLOUDS THE REMAINDER OF THE WEEKEND. HAVE TRENDED TO COOL SIDE OF GUIDANCE THROUGH THE PERIOD. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE TUESDAY AND TUESDAY NIGHT AS A WARM FRONT LIFTS THROUGH. IN THE WARM AIRMASS WEDNESDAY THROUGH FRIDAY THERE COULD BE SOME POP UP SHOWERS AND THUNDERSTORMS...CONTINUING THE 20 POPS. OTHERWISE A WARMING TREND WITH HIGHS ABOVE NORMAL. USED A BLEND OF GUIDANCE...ESPECIALLY HPC. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... HIGH PRESSURE IS BUILDING IN THROUGH TONIGHT. THE CLOUDS WILL SLOWLY DECREASE AND THE CEILINGS ARE RISING AND WILL BE VFR BY MID AFTERNOON. SKIES SHOULD BE CLEAR BY DARK. NOT EXPECTING MUCH FOG AT THE TAF SITES BUT SOME MVFR FOG MAY OCCUR AT FAVORED LOCATIONS. VFR SATURDAY WITH SOME CIRRUS AND A LIGHT NORTHWEST WIND. .OUTLOOK...NON VFR POSSIBLE IN SHOWERS AND THUNDERSTORMS MONDAY NIGHT THROUGH TUESDAY. && .MARINE... DROPPING THE SMALL CRAFT ADVISORY ON THE EXTREME WEST END OF THE LAKE AS THE HIGH IS BUILDING IN. OTHERWISE NO CHANGES TO THE HEADLINES. THE ONLY CONCERN IS THAT THE WAVES COULD BE NEAR SMALL CRAFT ADVISORY CRITERIA SATURDAY AFTERNOON IN THE NORTHWEST FLOW...THIS WILL HAVE TO BE MONITORED. OTHERWISE NOT EXPECTING CONDITIONS TO MEET SMALL CRAFT ADVISORY CONDITIONS ON THE LAKE IN A MAINLY SOUTHWEST FLOW. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR OHZ003-006>012-017>019-027-028-036-089. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT SUNDAY FOR OHZ013-014-020>023-029>033-037-038-047. PA...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT SATURDAY FOR PAZ001. FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT SUNDAY FOR PAZ002-003. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ146>149. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LEZ142>145. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...KIELTYKA AVIATION...KIELTYKA MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
332 PM CDT FRI MAY 24 2013 .SHORT TERM (TONIGHT)...THIS MORNINGS SOUTHERN MCV ASSISTED IN THE DEVELOPMENT OF A LINE OF SHOWERS AND THUNDERSTORMS ACROSS THE WESTERN BRUSH COUNTRY LATE MORNING AND EARLY AFTERNOON. FOLLOWING CLOSE TO THE HIGH RES 18Z HRRR FOR THE REST OF THIS AFTERNOON AND EVENING...WHICH WAS THE ONLY MODEL THAT SEEMED TO HAVE A DECENT HANDLE ON THE SITUATION. THE LINE WILL CONTINUE EAST INTO THE INLAND COASTAL BEND OVER THE NEXT 2 HOURS...THEN POSSIBLY WEAKEN AS OUTFLOW BOUNDARY PUSHES OUT AHEAD OF IT (MAY BE EVIDENCE OF THIS OUTFLOW BOUNDARY ALREADY DEVELOPING. THE ENVIRONMENT ACROSS THE EASTERN BRUSH COUNTRY AND COASTAL BEND IS UNSTABLE...WITH MLCAPE 2000-2500 J/KG AND UNCAPPED. SHEAR IS RELATIVELY WEAK...NEVERTHELESS A FEW STRONGER STORMS PRODUCING SMALL HAIL AND WIND GUSTS UP TO 50 MPH ARE POSSIBLE OVER THE NEXT COUPLE OF HOURS. CONVECTION SHOULD GRADUALLY END AROUND OR AFTER SUNSET. && .LONG-TERM (SATURDAY THROUGH FRIDAY)...WEAK SHORTWAVES WILL CONTINUE TO AFFECT SOUTH TEXAS ON SATURDAY AND INTO SUNDAY. MODELS ALL INDICATE ENERGY WITH THESE SHORTWAVES...BUT ARE A BIT DIFFERENT IN THE FINER DETAILS. STILL THINK THE NEXT WAVE TOMORROW COULD BRING A SLIGHT CHANCE FOR THUNDERSTORMS TO THE AREA. HAVE SPREAD THE SLIGHT CHANCE AREA FARTHER EAST GIVEN INCREASED MOISTURE FARTHER EAST THAN PREVIOUS MODELS HAD INDICATED. HAVE A LINGERING 10 POP WITH SLIGHT CHANCE WORDING FOR SUNDAY AS A SHORTWAVE WEAKER THAN THE OTHERS PASSES BY...BUT GUIDANCE STILL INDICATING SOME QPF ACROSS THE AREA. FOR MONDAY AND TUESDAY HIGH PRESSURE RIDGE BUILDS STRONGER ACROSS THE AREA WHILE 850 THETA E RIDGE SHIFTS WESTWARD. THIS WILL DRY THINGS OUT A BIT IN THE MID LEVELS AND ALLOW TEMPERATURES TO INCREASE. INCREASED PRESSURE GRADIENT WITH RESULTING FROM THE STRENGTHENING RIDGE TO THE EAST WILL ALSO INCREASE WINDS ACROSS THE AREA EARLY IN THE WEEK. SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE BY MID-WEEK. AN UPPER LEVEL TROUGH WILL BE DIGGING INTO THE WESTERN US BY MID WEEK AS WELL. MODEL SOLUTIONS HAVE NOT BEEN CONSISTENT WITH THE AMPLITUDE OF THIS TROUGH. SOME MODELS INDICATE A PRETTY DEEP TROUGH DIGGING AS FAR SOUTH AS NORTHERN MEXICO. OTHER MODELS SHOW A MUCH WEAKER TROUGH. NOT CONFIDENT YET IN CHANCES FOR PRECIP THURSDAY/FRIDAY...BUT WILL LEAVE 20 POPS FROM PREVIOUS FORECAST AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 76 89 75 90 75 / 30 10 10 10 10 VICTORIA 74 88 72 90 71 / 30 20 10 10 10 LAREDO 75 92 74 96 74 / 30 20 10 10 10 ALICE 75 89 73 92 73 / 30 20 10 10 10 ROCKPORT 75 87 75 88 76 / 30 10 10 10 10 COTULLA 74 91 72 95 72 / 30 30 10 10 10 KINGSVILLE 76 90 75 91 74 / 30 10 10 10 10 NAVY CORPUS 75 86 75 87 76 / 30 10 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ JR/76...SHORT TERM PZ/83...LONG TERM
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
104 PM CDT FRI MAY 24 2013 .UPDATE... 18Z AVIATION DISCUSSION INCLUDED BELOW. SMALL UPDATE MOSTLY TO BUMP UP HIGH TEMPS ACROSS THE BOARD TODAY GIVEN RECENT OBSERVED TRENDS. POP-WISE...THE BEST CHANCES FOR AFTN TSTRMS ARE TENDING TO FAVOR OUR EASTERN COUNTIES IN LIGHT OF A SLOWLY-RETREATING AREA OF CUMULUS OBSERVED FROM QUANAH SOUTH TO HASKELL. RECENT HRRR RUNS SEEM THE MOST CREDIBLE WITH INITIATION NEAR OUR EASTERN-MOST COUNTIES BY EARLY-MID AFTN WITH REDUCED CHANCES FARTHER WEST. RECENT LUBBOCK RADAR AND WTM STATIONS HAVE SHOWN A SUBTLE OUTFLOW BOUNDARY LIFTING NORTHWEST BETWEEN TAHOKA AND GRAHAM...ALTHOUGH I AM NOT OPTIMISTIC THIS FEATURE WILL IMPROVE CHANCES FOR PRECIP ON THE CAPROCK AS WATER VAPOR SHOWS A NARROW ZONE OF SUBSIDENCE SPREADING NORTH. REMAINDER OF THE FORECAST REMAINS IN CHECK. && .AVIATION... VFR CONDITIONS THIS AFTERNOON COULD BE THREATENED BY A FEW +TSRA WITH THE BEST CHANCE OF THIS OCCURRING AT CDS...HOWEVER LOW COVERAGE OF STORMS IMPLIES KEEPING PRECIP MENTION OUT FOR NOW. CONFIDENCE IS HIGHER THAT LOW CIGS AND/OR SOME LIGHT FOG WILL DEVELOP EARLY SAT MORNING AT THE TERMINALS...SO HAVE INSERTED A PERIOD OF MVFR CONDITIONS AS MOIST SELY WINDS REMAIN INTACT. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 84 60 84 60 93 / 20 20 20 20 20 TULIA 83 62 83 60 92 / 20 20 20 20 10 PLAINVIEW 84 63 83 61 91 / 20 20 20 20 10 LEVELLAND 85 64 84 62 92 / 20 20 20 20 10 LUBBOCK 84 65 83 63 92 / 20 20 20 20 10 DENVER CITY 85 64 84 61 92 / 20 20 20 20 10 BROWNFIELD 85 65 84 62 92 / 20 20 20 20 10 CHILDRESS 83 66 85 66 93 / 30 20 20 20 10 SPUR 83 66 82 63 91 / 20 20 20 20 10 ASPERMONT 84 67 84 66 92 / 30 20 20 20 10 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 93/99/93
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
336 PM CDT FRI MAY 24 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 334 PM CDT FRI MAY 24 2013 AT 3 PM...A 1003 MB HIGH PRESSURE SYSTEM...CENTERED OVER LAKE MICHIGAN...KEPT SKIES PARTLY SUNNY ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MEANWHILE FURTHER WEST...A SHORT WAVE WAS PRODUCING SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN QUARTER OF THE DAKOTAS AND WESTERN MINNESOTA. THE MESO AND DETERMINISTIC MODELS ARE CONTINUING TO STRUGGLE WITH THE EASTWARD PROGRESS OF THIS PRECIPITATION TONIGHT. THE ECMWF AND HRRR MOVE THIS PRECIPITATION ACROSS MOST OF FORECAST AREA BY 25.06Z. MEANWHILE THE NMM...ARW...GFS...GEM...RAP... AND NAM MAINLY CONFINE THE PRECIPITATION WEST OF THE MISSISSIPPI RIVER THIS EVENING...AND THEN MOVES IT ACROSS THE REMAINDER OF THE AREA OVERNIGHT. SINCE THE CONVECTION ACROSS THE DAKOTAS WILL BE MOVING INTO AN AREA WITH LESS FRONTOGENETIC FORCING...MOISTURE TRANSPORT...WEAK ISENTROPIC LIFT...AND DRIER AIR...DECIDED TO TREND THE FORECAST TOWARD THE LATTER MODEL SET. IN ADDITION...THE RADAR ECHOS ACROSS WESTERN MINNESOTA ARE SHOWING A DECREASING TREND. EVEN BY DOING THIS...THERE IS SOME VARIATIONS AMONGST THEM...SO TRIED TO GO WITH AN ENSEMBLE APPROACH WHEN ASSIGNING THE HOURLY PRECIPITATION CHANCES. THE HIGHEST PRECIPITATION CHANCE AND AMOUNTS /UP TO A HALF INCH/ WILL BE FOUND ACROSS ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. ON SATURDAY...THE SHORT WAVE WILL MOVE EAST SOUTHEAST ACROSS IOWA. AS THIS OCCURS...THE 850 MB MOISTURE TRANSPORT AND ISENTROPIC LIFT WILL GRADUALLY WEAKEN. AS A RESULT...WENT WITH A DECREASING TREND IN THE PRECIPITATION TRENDS FROM LATE MORNING INTO THE AFTERNOON. ADDITIONAL RAIFALL AMOUNTS WILL BE LESS THAN 2 TENTHS OF AN INCH. WITH THE 24.12Z AND 24.18Z MODELS IN GOOD AGREEMENT THAT THERE WILL BE LESS THAN 100 J/KG CAPES...JUST KEPT AN ISOLATED THUNDERSTORM CHANCE MAINLY WEST AND SOUTH IF THE INTERSTATE 94 CORRIDOR. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 334 PM CDT FRI MAY 24 2013 FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE WARM FRONT WILL REMAIN WELL SOUTHWEST OF THE FORECAST AREA. AS A RESULT... SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN WILL REMAIN CLOUDY WITH PERIODIC SHOWERS AND MAYBE AN ISOLATED THUNDERSTORM. OVER THE PAST 3 DAYS...THE CONSALL HAS CONTINUED TO TREND TOWARD COOLER HIGH TEMPERATURES FOR SUNDAY. IT NOW HAS HIGH TEMPERATURES AROUND 60. MEANWHILE THE ECMWF ONLY HAS HIGH TEMPERATURES IN THE LOWER 50S FOR THESE AREAS. SINCE THE ECMWF TYPICALLY VERIFIES THE BEST FOR THIS TIME PERIOD...WENT WITH A BLEND OF THE CONSALL...CONSALLBC...AND EMCWF. FROM MEMORIAL DAY INTO TUESDAY...THE MODELS ARE CONTINUING TO SHOW THAT A WARM FRONT WILL MOVE NORTHWARD INTO THE AREA. THIS WILL ALLOW ML CAPES TO CLIMB INTO THE 1K TO 3K J/KG RANGE. AS A RESULT...EXPECT THE THUNDERSTORM CHANCES TO INCREASE DURING THIS TIME PERIOD. THE 0-3KM SHEAR WOULD BE FAVORABLE FOR THE POSSIBILITY THAT A FEW THUNDERSTORMS MAY BE CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. FROM TUESDAY NIGHT INTO FRIDAY...THE MODELS CONTINUE TO STRUGGLE ON WHERE THE WARM SECTOR WILL BE LOCATED. THIS GREATLY AFFECTS THE WHERE THE PRECIPITATION MAY BE LOCATED. IN ADDITION...IT WILL ALSO AFFECT THE SHEAR AND INSTABILITY...THUS...THERE IS A LOT OF UNCERTAINTY ON WHETHER THERE WILL BE ANY SEVERE WEATHER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1214 PM CDT FRI MAY 24 2013 FOCUS OF THE FORECAST IS ON THE POTENTIAL FOR SHOWERS LATE TONIGHT INTO SATURDAY MORNING. SHORT WAVE TROUGH IN THE LEE OF THE ROCKIES OVER WYOMING IS EXPECTED TO TOP THE MEAN RIDGE AND SLIDE ACROSS THE REGION LATE TONIGHT AND SATURDAY MORNING. AN AXIS OF MOISTURE TRANSPORT IS EXPECTED TO DEVELOP THIS AFTERNOON AHEAD OF THIS WAVE THEN BEND TO THE NORTHEAST AND BE FOCUSED INTO THE AREA LATE TONIGHT. HOWEVER...THIS WILL BE WEAKENING THROUGH THE NIGHT AND WILL NOT BE VERY STRONG BY THE TIME IT BECOMES FOCUSED ON THE LOCAL AREA. THE FORCING FROM THE WAVE AND THE WEAK MOISTURE TRANSPORT SHOULD BE ENOUGH TO GENERATE SOME SHOWERS. EXPECT THESE WILL MOVE INTO BOTH TAF SITES BETWEEN 09Z AND 12Z. THE SHOWERS SHOULD BE LIGHT ENOUGH TO NOT PRODUCE ANY VISIBILITY RESTRICTION BUT COULD PRODUCE SOME MVFR CEILINGS AS THE RAIN SATURATES THE LOW LEVELS OF THE COLUMN ENOUGH TO ALLOW THE CEILINGS TO LOWER. THE 24.09Z SREF SHOWS THE BETTER PROBABILITIES OF THIS OCCURRING ARE WEST OF THE MISSISSIPPI RIVER SO HAVE INCLUDED THIS AT KRST. THE ISENTROPIC UPGLIDE ON THE 300K SURFACE BEGINS TO WEAKEN AFTER 15Z SATURDAY BUT DOES CONTINUE FOR THE REMAINDER OF THE MORNING AND SHOULD BE ENOUGH TO KEEP SOME SHOWERS OR SPRINKLES GOING THROUGH THE END OF THE FORECAST PERIOD. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SATURDAY ISSUED AT 248 PM CDT FRI MAY 24 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE STRETCHING FROM HUDSON BAY TO LAKE MICHIGAN TO THE CENTRAL GULF COAST. A FEW STRANDS OF CIRRUS IS INVADING NW WISCONSIN EARLY THIS AFTERNOON...BUT OTHERWISE...CLEAR AND COOL CONDITIONS ARE PREVAILING. LOOKING UPSTREAM...STRENGTHENING RETURN FLOW OVER THE PLAINS IS CREATING A BAND OF SHOWERS AND THUNDERSTORMS OVER EASTERN NORTH AND SOUTH DAKOTA. AS THIS WARM FRONT SHIFTS EAST TONIGHT...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...A JET STREAK...BETWEEN A SE DIVING SHORTWAVE OVER THE EASTERN GREAT LAKES AND A MID-LEVEL RIDGE OVER THE GREAT PLAINS...WILL SLIDE SOUTHEAST ACROSS THE REGION. RIGHT REAR QUAD OF THIS JET STREAK WILL SHIFT OVER NORTH-CENTRAL AND NORTHEAST WISCONSIN AFTER MIDNIGHT. DESPITE VERY DRY AIR IN THE LOW LEVELS...MODELS SPIT OUT A COUPLE BANDS OF PRECIP AS A RESULT OF MID-LEVEL CONVERGENCE/FGEN AND UPPER DIVERGENCE...THOUGH DIFFER IN THEIR PLACEMENT. THE LARGEST BAND WILL BE TIED TO THE PRIMARY BAROCLINIC ZONE OFF TO OUR WEST AND SOUTHWEST...WHICH THE NAM/GFS HAVE TRENDED A BIT TO THE WEST. HOWEVER...THE 12Z MESOMODELS CONTINUE TO PUSH THIS BAND OF PRECIP OVER CENTRAL WISCONSIN BETWEEN 06Z AND 12Z. DO NOT HAVE A GOOD FEEL WHERE THIS BAND WILL END UP. BUT LIGHT LOW LEVEL SE WINDS WILL SUPPLY A STEADY DIET OF DRY AIR...SO PRECIP WILL HAVE TO FALL OUT OF A MID-DECK...AND GIVEN THE WEAK FORCING...CANNOT SEE MUCH MORE THAN SPRINKLES LIKE THE PREVIOUS FORECASTER MENTIONED. GIVEN THE LOW IMPACT AND TO MATCH UP WITH OFFICES TO THE WEST AND NORTH...WILL KEEP THE MENTION OF SPRINKLES OVER CENTRAL WISCONSIN. A LOWERING CLOUD DECK WILL KEEP TEMPS WARMER THAN LAST NIGHT AND WILL GO WITH MID 30S NORTH TO MID 40S SOUTH. PATCHY FROST WILL REMAIN POSSIBLE OVER FAR NORTHERN WISCONSIN. SATURDAY...RIGHT REAR QUAD WILL SLIDE TO THE SOUTH-CENTRAL GREAT LAKES DURING THE MORNING. ANY SPRINKLE ACTIVITY SHOULD BE ENDING EARLY SO IT DOES NOT SEEM WORTH MENTIONING IN THE FORECAST. THE DEPARTING MID-LEVEL CONVERGENCE SHOULD ALLOW DRY AIR TO RETURN TO NORTHEAST WISCONSIN LATE MORNING ONWARD WHEN SHOULD SEE DECREASING CLOUDS. CLOUDS TO HANG LONGER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN...CLOSER TO THE PRIMARY BAROCLINIC ZONE. WITH THE ADDITIONAL CLOUD COVER...TEMPS TO REMAIN NEAR OR SLIGHTLY COOLER THAN TODAYS READINGS...AND WILL RANGE FROM THE UPPER 50S OVER CENTRAL WISCONSIN TO THE MIDDLE 60S OVER NORTHEAST WISCONSIN. .LONG TERM...SATURDAY NIGHT THROUGH FRIDAY ISSUED AT 248 PM CDT FRI MAY 24 2013 GOOD AGREEMENT BETWEEN GUIDANCE IN BIG PICTURE WITH STRENGTHENING RIDGE IN THE EAST WHILE TROF PERSISTS OVER THE WEST. PLEASANT WEATHER IS EXPECTED THROUGH MUCH OF THIS MEMORIAL DAY WEEKEND. AT THE SURFACE DRY HIGH PRESSURE TO THE EAST WILL MAINTAIN EAST TO SOUTHEAST FLOW OVER THE REGION. SOME MODEL DISCONNECT WITH HOW HANDLE SHORT WAVE ACTIVITY EXITING WESTERN TROF INTO THE PLAINS AND WESTERN LAKES LATE THIS HOLIDAY PERIOD. HAVE STAYED TOWARD DRIER EC/GFS...WITH IDEA THAT HIGH WILL KEEP PCPN TO OUR SOUTHWEST SUN AND MON. NAM APPEARS THE OUTLIER...TOO STRONG AND FAST. LIGHT WINDS AND DRY CONDITIONS TO LEAD TO ANOTHER COOL NIGHT FOR NORTHEAST WI...WITH PATCHY FROST OVER PARTS OF FAR NORTHEAST WI. TROF DEEPENS WEST BEGINNING OF NEXT WEEK PUMPING UP RIDGE JUST TO OUR EAST. THIS TO LEAD TO WARMER TEMPS AND INCREASING HUMIDITY AND INSTABILITY AS WARM FRONT LIFTS NORTH TOWARDS...OR THROUGH STATE. AGAIN SOME DISPARITY ON HOW FAR NORTH FRONT WILL GO...WITH EC LINGERING IT OVER NORTHERN WI. COULD BE LOOKING A PERIOD OF ACTIVE WEATHER NEXT WED/THU WITH POSSIBILITY OF PERIODS OF HEAVY RAINFALL AS PW`S INCREASE TO 1.5. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 101 PM CDT FRI MAY 24 2013 VFR CONDITIONS EXPECTED FOR THE NEXT FEW DAYS. EVEN ANY SPRINKLES THAT DEVELOP LATE TNGT/EARLY SAT SHOULD BE FALLING OUT OF A MIDDLE CLD DECK WITH HIGH BASES. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TE AVIATION.......MPC