Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 06/28/13


AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
840 AM PDT WED JUN 26 2013 ...MUCH WARMER WEATHER ON THE WAY... .DISCUSSION...AS OF 08:40 AM PDT WEDNESDAY...HUMID AIR PERSISTS OVER THE REGION WITH DEWPOINTS IN THE SIXTIES THIS MORNING. A THIN LAYER OF PATCHY FOG IS AFFECTING PORTIONS OF THE COAST AND NORTH BAY WITH VISIBILITIES AS LOW AS A QUARTER MILE IN SPOTS. EXPECT FOG TO BURN OFF BY MID MORNING AND DAYTIME HIGHS TO RUN FIVE TO TEN DEGREES ABOVE YESTERDAY. MODEL OUTPUT SO FAR THIS MORNING CONTINUES TO INDICATE PROLONGED WARMING TREND. FORECAST ON TRACK AND NO UPDATES NECESSARY AT THIS TIME. && .PREV DISCUSSION...AS OF 3:00 AM PDT WEDNESDAY...OVERNIGHT RAIN ENDED ACROSS OUR CWA AFTER DROPPING A WIDE RANGE OF AMOUNTS FOR SUNDAY NIGHT TO TUESDAY NIGHT. VALUES RANGED FROM LESS THAN A TENTH FOR MOST OF THE SOUTHERN CWA ALL OF THE WAY UP TO OVER 5 INCHES FOR SPOTS IN THE NORTH BAY. STILL PLENTY OF MOIST AIR IN PLACE WHICH IS HELPING TO KEEP DEW POINTS AT HIGH LEVELS EARLY THIS MORNING ALONG WITH SOME PATCHY FOG NOW BEING INDICATED BY THE SATELLITE FOG PRODUCT. SURFACE OBS ARE ALSO STARING TO INDICATE A FEW POCKETS OF REDUCED VISIBILITIES AND THIS SHOULD CONTINUE TO INCREASE THROUGH THE FIRST HALF OF THE MORNING. MAIN STORY FOR THE REST OF THE WEEK THROUGH MOST OF NEXT WEEK WILL BE THE MUCH WARMER WEATHER THAT WILL RETURN TO THE ENTIRE REGION AS A RIDGE OF HIGH PRESSURE BUILDS TO MUCH OF THE WEST. CONFIDENCE IS VERY HIGH THAT VERY WARM TO HOT WEATHER WILL RETURN TO INLAND SPOTS AS 850 MB TEMPS RISE TO AROUND 30C WHILE 500 MB HEIGHT GET CLOSE TO 600 DM (MOST LIKELY 596-598 DM AROUND HERE). BOTH OF THESE VALUES ALONG WITH THE GENERAL PATTERN SUGGEST SOME HIGHS (PLUS EVEN A FEW OVERNIGHT LOWS) WILL APPROACH RECORD VALUES. WHAT IS NOT ENTIRE CLEAR IS IF WE ARE LOOKING AT A WIDESPREAD HEAT WARNING EVENT OR JUST VERY WARM READINGS. WHAT IS INTERESTING TO NOTE IS THE NEW ECMWF HAS 850 MB TEMPS CLOSET TO 28-30C WHILE THE GFS IS NOW MORE IN THE 30-32C RANGE. CLOSER TO THE COAST...THERE IS UNCERTAINTY IF THE HEAT WILL PUSH ALL OF THE WAY TO THE OCEAN OR IF THE THERMAL TROUGH WILL NOT BE ABLE TO MAKE IT THAT FAR. ALSO WORTH POINTING OUT THAT THE TEMPERATURE ANOMALIES ARE ONLY EXPECTED TO BE 2 TO 3 ABOVE NORMAL -- STILL IMPRESSIVE, HOWEVER SHORT OF NUMBERS THAT WE LIKE TO SEE FOR A MAJOR EVENT. OVERNIGHT LOWS WILL ALSO BE OF NOTE FROM THE EVENT WITH MANY HIGHER ELEVATION LOCATIONS STRUGGLING TO COOL OUT OF THE 70S (SOME SPOTS MAY STAY IN THE LOWER 80S AT NIGHT). MANY URBAN SPOTS WILL LIKELY STAY IN THE 60S. AFTER LOOKING AT THE VARIOUS SOLUTIONS, DECIDED TO BOOST SOME OF THE HIGHS (ESPECIALLY NEAR THE COAST) AND LOWS FOR HIGHER ELEVATION SPOTS PLUS PARTS OF THE SANTA CLARA VALLEY. CPC KEEPS THE WARMER THAN NORMAL WEATHER CONTINUING OUT FOR THE 6-10 AND 8-14 DAY PERIODS WITH AN ABOVE NORMAL CONFIDENCE LEVEL. THAT WOULD TAKE US OUT TO JULY 9TH. && .AVIATION...AS OF 4:35 AM PDT WEDNESDAY...UPPER LEVEL HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE REGION THROUGH THE FORECAST. ABUNDANT STRATUS OFFSHORE AND HIGH SURFACE MOISTURE (DUE TO THE RAIN SHOWERS OVER THE PAST FEW DAYS) WILL MAKE FOR A DIFFICULT FORECAST THROUGH AT LEAST THE EARLY AFTERNOON HOURS. POSSIBLE REDUCED VISIBILITIES MAY IMPACT THE TERMINALS THROUGH THE EARLY MORNING HOURS. OTHERWISE...MODERATE WEST WINDS WILL BE PRESENT ACROSS THE AREA THIS AFTERNOON THROUGH THE EARLY EVENING HOURS. VICINITY OF KSFO...POSSIBLE IFR CIGS THROUGH 16Z. VERY LOW CONFIDENCE. VFR CONDITIONS WILL BE POSSIBLE AFTER 19Z...HOWEVER...A FEW OF THE SHORT TERM MODELS INDICATE CLEARING A FEW HOURS LATER...CLOSER TO 21Z. MODERATE ONSHORE TO 15 KT THIS AFTERNOON. KSFO BRIDGE APPROACH...PATCHY LOW CLOUDS MAY IMPACT THE APPROACH AN HOUR LATER THAN THE TERMINAL. LOW CONFIDENCE. MONTEREY BAY AREA TERMINALS...POSSIBLE VLIFR CIGS AND VIS POSSIBLE THROUGH THE EARLY MORNING HOURS. THE HRRR AND LOCAL WRF INDICATE THAT KMRY COULD SEE LOW CLOUDS ALL DAY...ADDING TO THE UNCERTAINTY OF THE FORECAST. OTHERWISE...MODERATE ONSHORE THIS AFTERNOON WITH AN EARLY RETURN OF STRATUS THIS EVENING. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: AC/BELL AVIATION/MARINE: RILEY VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
439 AM PDT WED JUN 26 2013 ...MUCH WARMER WEATHER ON THE WAY... .DISCUSSION...AS OF 3:00 AM PDT WEDNESDAY...OVERNIGHT RAIN ENDED ACROSS OUR CWA AFTER DROPPING A WIDE RANGE OF AMOUNTS FOR SUNDAY NIGHT TO TUESDAY NIGHT. VALUES RANGED FROM LESS THAN A TENTH FOR MOST OF THE SOUTHERN CWA ALL OF THE WAY UP TO OVER 5 INCHES FOR SPOTS IN THE NORTH BAY. STILL PLENTY OF MOIST AIR IN PLACE WHICH IS HELPING TO KEEP DEW POINTS AT HIGH LEVELS EARLY THIS MORNING ALONG WITH SOME PATCHY FOG NOW BEING INDICATED BY THE SATELLITE FOG PRODUCT. SURFACE OBS ARE ALSO STARING TO INDICATE A FEW POCKETS OF REDUCED VISIBILITIES AND THIS SHOULD CONTINUE TO INCREASE THROUGH THE FIRST HALF OF THE MORNING. MAIN STORY FOR THE REST OF THE WEEK THROUGH MOST OF NEXT WEEK WILL BE THE MUCH WARMER WEATHER THAT WILL RETURN TO THE ENTIRE REGION AS A RIDGE OF HIGH PRESSURE BUILDS TO MUCH OF THE WEST. CONFIDENCE IS VERY HIGH THAT VERY WARM TO HOT WEATHER WILL RETURN TO INLAND SPOTS AS 850 MB TEMPS RISE TO AROUND 30C WHILE 500 MB HEIGHT GET CLOSE TO 600 DM (MOST LIKELY 596-598 DM AROUND HERE). BOTH OF THESE VALUES ALONG WITH THE GENERAL PATTERN SUGGEST SOME HIGHS (PLUS EVEN A FEW OVERNIGHT LOWS) WILL APPROACH RECORD VALUES. WHAT IS NOT ENTIRE CLEAR IS IF WE ARE LOOKING AT A WIDESPREAD HEAT WARNING EVENT OR JUST VERY WARM READINGS. WHAT IS INTERESTING TO NOTE IS THE NEW ECMWF HAS 850 MB TEMPS CLOSET TO 28-30C WHILE THE GFS IS NOW MORE IN THE 30-32C RANGE. CLOSER TO THE COAST...THERE IS UNCERTAINTY IF THE HEAT WILL PUSH ALL OF THE WAY TO THE OCEAN OR IF THE THERMAL TROUGH WILL NOT BE ABLE TO MAKE IT THAT FAR. ALSO WORTH POINTING OUT THAT THE TEMPERATURE ANOMALIES ARE ONLY EXPECTED TO BE 2 TO 3 ABOVE NORMAL -- STILL IMPRESSIVE, HOWEVER SHORT OF NUMBERS THAT WE LIKE TO SEE FOR A MAJOR EVENT. OVERNIGHT LOWS WILL ALSO BE OF NOTE FROM THE EVENT WITH MANY HIGHER ELEVATION LOCATIONS STRUGGLING TO COOL OUT OF THE 70S (SOME SPOTS MAY STAY IN THE LOWER 80S AT NIGHT). MANY URBAN SPOTS WILL LIKELY STAY IN THE 60S. AFTER LOOKING AT THE VARIOUS SOLUTIONS, DECIDED TO BOOST SOME OF THE HIGHS (ESPECIALLY NEAR THE COAST) AND LOWS FOR HIGHER ELEVATION SPOTS PLUS PARTS OF THE SANTA CLARA VALLEY. CPC KEEPS THE WARMER THAN NORMAL WEATHER CONTINUING OUT FOR THE 6-10 AND 8-14 DAY PERIODS WITH AN ABOVE NORMAL CONFIDENCE LEVEL. THAT WOULD TAKE US OUT TO JULY 9TH. && .AVIATION...AS OF 4:35 AM PDT WEDNESDAY...UPPER LEVEL HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE REGION THROUGH THE FORECAST. ABUNDANT STRATUS OFFSHORE AND HIGH SURFACE MOISTURE (DUE TO THE RAIN SHOWERS OVER THE PAST FEW DAYS) WILL MAKE FOR A DIFFICULT FORECAST THROUGH AT LEAST THE EARLY AFTERNOON HOURS. POSSIBLE REDUCED VISIBILITIES MAY IMPACT THE TERMINALS THROUGH THE EARLY MORNING HOURS. OTHERWISE...MODERATE WEST WINDS WILL BE PRESENT ACROSS THE AREA THIS AFTERNOON THROUGH THE EARLY EVENING HOURS. VICINITY OF KSFO...POSSIBLE IFR CIGS THROUGH 16Z. VERY LOW CONFIDENCE. VFR CONDITIONS WILL BE POSSIBLE AFTER 19Z...HOWEVER...A FEW OF THE SHORT TERM MODELS INDICATE CLEARING A FEW HOURS LATER...CLOSER TO 21Z. MODERATE ONSHORE TO 15 KT THIS AFTERNOON. KSFO BRIDGE APPROACH...PATCHY LOW CLOUDS MAY IMPACT THE APPROACH AN HOUR LATER THAN THE TERMINAL. LOW CONFIDENCE. MONTEREY BAY AREA TERMINALS...POSSIBLE VLIFR CIGS AND VIS POSSIBLE THROUGH THE EARLY MORNING HOURS. THE HRRR AND LOCAL WRF INDICATE THAT KMRY COULD SEE LOW CLOUDS ALL DAY...ADDING TO THE UNCERTAINTY OF THE FORECAST. OTHERWISE...MODERATE ONSHORE THIS AFTERNOON WITH AN EARLY RETURN OF STRATUS THIS EVENING. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: BELL AVIATION/MARINE: RILEY VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1117 PM EDT THU JUN 27 2013 .SYNOPSIS... SURFACE LOW PRESSURE ACROSS EASTERN PENNSYLVANIA WILL MOVE SLOWLY NORTH THROUGH EASTERN NEW YORK TONIGHT INTO FRIDAY. A SERIES OF LOW PRESSURE SYSTEMS WILL THEN IMPACT THE REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. BERMUDA HIGH PRESSURE STRENGTHENS AND BUILDS BACK TOWARD THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... TSTMS WILL CONTINUE TO HEAD NORTH THROUGH THE FORKS AND SE CT OVER THE NEXT COUPE OF HOURS. WARM FRONT NOW ALONG THE CT COAST. 00Z KOKX SOUNDING CAME IN WITH A PW OF 1.73 INCHES. THIS WAS A TENTH BLW THE 12Z SOUNDING...BUT STILL INDICATIVE OF AN AIRMASS CAPABLE OF TORRENTIAL DOWNPOURS. THE FFA REMAINS IN EFFECT. HIGHEST FLOOD THREAT BASED ON THE RR QUAD OF THE H2 JET STILL LOOKS TO FAVOR THE WRN HALF OF THE CWA. SLY FLOW IN THE WARM SECTOR BEHIND THE FRONT COULD PRODUCE ADDITIONAL LLVL SHEAR AS THE FLOW INTERACTS WITH LAND. THIS SHOULD RESULT IN ISOLD SVR THREAT THRU THE NGT...ESPECIALLY THE S COASTS. 00Z HPC QPF WITH MANUAL ADJUSTMENTS UPWARD THRU 6Z USED IN THE GRIDS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... THE GREAT LAKES UPPER LOW CONTINUES TO DEEPEN INTO THE NORTHEAST DURING THIS TIME PERIOD. DRYING CONDITIONS ARE LIKELY FRIDAY MORNING ACROSS WESTERN SECTIONS IN THE WAKE OF THE SHORTWAVE...WITH PARTIAL CLEARING. FAR EASTERN SECTIONS WILL LIKELY SEE MORE IN THE WAY OF CLOUD COVER...AS THEY WILL BE ON THE FRINGE OF THE TROPICAL CONVEYOR BELT. TIMING OF SHORTWAVES AROUND THE UPPER LOW WILL DETERMINE EXACT TIMING OF ADDITIONAL SHRA/TSRA ACTIVITY FRI AFT/FRI NIGHT...BUT HIGHEST PROBABILITY WILL LIKELY BE ACROSS INTERIOR FRI AFT/EVE WITH DIURNAL HEATING. FLASH FLOOD THREAT APPEARS TO BE LOWER ON FRIDAY AS PWATS DROP TO 1.25 TO 1.5 INCHES IN THE WAKE OF THE SHORTWAVE. MARGINAL INSTABILITY AND SHEAR ALSO INDICATE THAT STRONG TO SEVERE STORMS WOULD BE ISOLATED...BUT THIS WILL ULTIMATELY BE DETERMINED BY STRENGTH OF THE NEXT SHORTWAVE AND AMOUNT OF HEATING. && .LONG TERM /SATURDAY THROUGH THURSDAY/... UNSETTLED...MUGGY AND WARM CONDITIONS WILL BE THE RULE FOR MUCH OF THE PERIOD AS AN UPPER TROF OVER THE NE AND OH VALLEY STATES THIS WEEKEND CLOSES OFF AND RETROGRADES TOWARD THE MID SECTION OF THE COUNTRY BY THE MIDDLE OF NEXT WEEK. THE AIRMASS WILL BECOME LOADED WITH MOISTURE AS A DEEP-LAYERED S/SW FLOW BECOMES ESTABLISHED BETWEEN THE RIDGE OVER THE WESTERN ATLANTIC AND THE UPPER TROF. THE BEST CHANCE FOR ORGANIZED HEAVY RAINFALL WILL BE ON SUNDAY AS LOW PRESSURE OVER THE TN AND OH VALLEYS LIFTS NORTH...SENDING A STATIONARY FRONT JUST SOUTH AND EAST OF THE AREA NORTHWARD AS A WARM FRONT. PW VALUES WILL BE AROUND 2 INCHES. THIS LOOKS TO BE A MAINLY HEAVY RAINFALL EVENT AS WIND SHEAR IS MARGINAL AND THE AIRMASS IS WARM ALOFT. SCT STRONG AND/OR SEVERE CONVECTION IS A POSSIBILITY SAT AFT/EVE...PRIMARILY NORTH AND WEST OF NYC...WHERE DEEP-LAYERED SHEAR WILL EXIST WITH THE RRQ OF THE UPPER JET LIFTING ACROSS THE HUDSON VALLEY. A LIMITING FACTOR ON SAT WILL BE A BRIEF DRYING OUT OF THE AIRMASS. EARLY NEXT WEEK...WITH THE FRONTAL BOUNDARY NORTH OF THE REGION AND THE AREA IN WARM SECTOR...CONVECTION LOOKS TO BE MAINLY DIURNAL IN NATURE. MON MAY STILL REMAIN WET AS MODEL SOLUTIONS DIVERGE WITH THE LOCATION OF THE BOUNDARY. THE 12Z ECMWF IS ACTUALLY WETTER ON MON THAN SUN...A COMPLETE OPPOSITE OF THE GFS...BUT THIS IS DUE TO A SLOWER TIMING OF THE FRONTAL WAVE. KEEP IN MIND AN AIRMASS THIS MOIST AND UNSTABLE WILL TRIGGER ISOLATED TO SCT CONVECTION ALMOST ANYTIME AND IT WILL NOT TAKE MUCH FOR SOME ORGANIZATION OF CLUSTERS TO FORM POCKETS OF HEAVY RAINFALL. THIS IS ESPECIALLY THE CASE SUN INTO MON. AS FOR TEMPS...LOOKING AT BOTH HIGHS AND LOWS RUNNING A FEW DEGREES ABOVE NORMAL. SHOULD THE AMOUNT OF CLOUD COVER FROM CONVECTION BE LESS...DAYTIME HIGHS COULD BE SEVERAL DEGREES WARMER THAN CURRENTLY FORECAST. GENERALLY LOOKING FOR HIGHS 80 TO 85...AND LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... LOW PRESSURE PASSES TO THE WEST TONIGHT AS IT DRIFTS NORTH. AN ASSOCIATED FRONTAL BOUNDARY STALLS OVER THE AREA ON FRIDAY. TSTMS NOW ONLY FOR KGON UNTIL AROUND MIDNIGHT. MVFR TO IFR OVERNIGHT WITH STILL SOME SHRA POSSIBLE...BUT NOT HIGH ENOUGH CHANCE TO INCLUDE IN TAFS. S-SE WINDS AROUND 15KT GUSTING TO 20-25 KT IN THE CITY UNTIL SHORTLY AFTER MIDNIGHT...BCMG S-SW 10-15KT OVERNIGHT. OCCASIONAL GUSTS TO 20 KT STILL POSSIBLE UNTIL AROUND 07Z. FOR FRIDAY...SCT SHRA AND TSTMS. BETTER OVERALL CHANCES IN THE AFTN. VFR AND SW GUSTS AROUND 20 KT DEVELOPING BY AROUND NOON. .OUTLOOK FOR 00Z SAT THROUGH TUESDAY... .FRI-TUE...SUB VFR POSSIBLE AT TIMES WITH PERIODS OF SHOWERS AND TSTMS. && .MARINE... DENSE FOG ADVY ISSUED FOR THE ERN WATERS THRU TNGT. OTHERWISE...SCA ON THE OCEAN WITH BUILDING SEAS THRU FRI. S/SW FLOW CONTINUES THROUGH FRIDAY NIGHT...BUT WINDS ARE EXPECTED TO BE BELOW SCA LEVELS. SCA SOUTHERLY SWELLS SHOULD CONTINUE THROUGH. HAVE CONTINUED TO UNDERCUT WNA GUIDANCE BY 1-2 FT BASED ON GUIDANCE TREND AND ITS PERFORMANCE THIS SUMMER. POTENTIAL EXISTS FOR AN EXTENDED PERIOD OF HAZARDOUS OCEAN SEAS VIA PERSISTENT LONG FETCH SOUTHERLY FLOW. WINDS ARE EXPECTED TO STAY BELOW CRITERIA. UNDERCUT WAVEWATCH BY A ABOUT A FOOT ON THE OCEAN WATERS FOR MUCH OF THE PERIOD. && .HYDROLOGY... PATTERN INTO TONIGHT CONTINUES TO LOOK CONDUCIVE TO BANDS OF HEAVY RAIN SHOWERS AND THUNDERSTORMS TRAINING OVER THE SAME AREA...WHICH WOULD CAUSE URBAN AND SMALL STREAM FLASH FLOODING. ON AVERAGE 1/2 TO 1 1/2 INCHES OF RAINFALL EXPECTED ACROSS LI AND CT...WITH 1 1/2 TO 2 1/2 INCHES OF RAINFALL ACROSS NE NJ AND THE LOWER HUDSON VALLEY. THE HIGHER AMOUNTS IN BOTH AREAS WILL BE TO THE N AND W. LOCALLY HIGHER AMOUNTS ARE LIKELY IN THE PATH OF TRAINING ACTIVITY. RAINFALL RATES OF 2 TO 3 INCHES PER HOUR HAVE BEEN OBSERVED WITH THE STRONGER THUNDERSTORMS THIS AFTERNOON. NEEDLESS TO SAY IF THIS TYPE OF ACTIVITY TRAINS OVER AN AREA FOR AN HOUR...URBAN AND SMALL STREAM FLASH FLOODING WILL OCCUR. THE MAIN THREAT FOR URBAN FLASH FLOODING LOOKS TO BE THROUGH 06Z ACROSS THE WESTERN 1/2 OF THE CWA...AND THROUGH AROUND DAYBREAK ACROSS LI/CT. SMALL STREAMS COULD CONTINUE RISING INTO FRIDAY MORNING. MEANWHILE...MAIN STEM RIVERS WILL SEE RISES...BUT THEY ARE EXPECTED TO REMAIN WELL WITHIN THEIR BANKS. WITH SOME UNCERTAINTY ON THE EVOLUTION OF CONVECTION ON FRIDAY...WILL CONTINUE FLASH FLOOD WATCH UNTIL 6 PM FRIDAY AND LET SUBSEQUENT SHIFTS TAKE DOWN IF NEEDED. ADDITIONAL BOUTS OF HEAVY SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS WEEKEND INTO EARLY NEXT WEEK...POSING ADDITIONAL THREATS FOR FLOODING. FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CTZ005>012. NY...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ067>075- 078>081-176>179. NJ...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NJZ002-004-006- 103>108. MARINE...DENSE FOG ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ330-340-345- 350. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ350-353- 355. && $$ AVIATION...JC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
959 PM EDT THU JUN 27 2013 .SYNOPSIS... SURFACE LOW PRESSURE ACROSS EASTERN PENNSYLVANIA WILL MOVE SLOWLY NORTH THROUGH EASTERN NEW YORK TONIGHT INTO FRIDAY. A SERIES OF LOW PRESSURE SYSTEMS WILL THEN IMPACT THE REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. BERMUDA HIGH PRESSURE STRENGTHENS AND BUILDS BACK TOWARD THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... TSTMS HAVE MADE IT INTO THE CITY WITH HVY RAINS SPREADING UP THE HUDSON VALLEY. ARC OF DEVELOPING CONVECTION TRACKING NEWD ACROSS LI AND WILL SOON BE INTO CT. THIS IS A WARM FRONT JUST OFF THE SFC AS EVIDENCED BY VEERING WINDS AT KDIX VIA THE VWP AS THE BAND PASSED THRU AROUND 00Z. WARM FRONT AT THE SFC PASSED THRU KBLM AFT 1Z. 00Z KOKX SOUNDING CAME IN WITH A PW OF 1.73 INCHES. THIS WAS A TENTH BLW THE 12Z SOUNDING...BUT STILL INDICATIVE OF AN AIRMASS CAPABLE OF TORRENTIAL DOWNPOURS. THE FFA REMAINS IN EFFECT. HIGHEST FLOOD THREAT BASED ON THE RR QUAD OF THE H2 JET STILL LOOKS TO FAVOR THE WRN HALF OF THE CWA. SLY FLOW IN THE WARM SECTOR BEHIND THE FRONT COULD PRODUCE ADDITIONAL LLVL SHEAR AS THE FLOW INTERACTS WITH LAND. THIS SHOULD RESULT IN ISOLD SVR THREAT THRU THE NGT...ESPECIALLY THE S COASTS. 00Z HPC QPF WITH MANUAL ADJUSTMENTS UPWARD THRU 6Z USED IN THE GRIDS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... THE GREAT LAKES UPPER LOW CONTINUES TO DEEPEN INTO THE NORTHEAST DURING THIS TIME PERIOD. DRYING CONDITIONS ARE LIKELY FRIDAY MORNING ACROSS WESTERN SECTIONS IN THE WAKE OF THE SHORTWAVE...WITH PARTIAL CLEARING. FAR EASTERN SECTIONS WILL LIKELY SEE MORE IN THE WAY OF CLOUD COVER...AS THEY WILL BE ON THE FRINGE OF THE TROPICAL CONVEYOR BELT. TIMING OF SHORTWAVES AROUND THE UPPER LOW WILL DETERMINE EXACT TIMING OF ADDITIONAL SHRA/TSRA ACTIVITY FRI AFT/FRI NIGHT...BUT HIGHEST PROBABILITY WILL LIKELY BE ACROSS INTERIOR FRI AFT/EVE WITH DIURNAL HEATING. FLASH FLOOD THREAT APPEARS TO BE LOWER ON FRIDAY AS PWATS DROP TO 1.25 TO 1.5 INCHES IN THE WAKE OF THE SHORTWAVE. MARGINAL INSTABILITY AND SHEAR ALSO INDICATE THAT STRONG TO SEVERE STORMS WOULD BE ISOLATED...BUT THIS WILL ULTIMATELY BE DETERMINED BY STRENGTH OF THE NEXT SHORTWAVE AND AMOUNT OF HEATING. && .LONG TERM /SATURDAY THROUGH THURSDAY/... UNSETTLED...MUGGY AND WARM CONDITIONS WILL BE THE RULE FOR MUCH OF THE PERIOD AS AN UPPER TROF OVER THE NE AND OH VALLEY STATES THIS WEEKEND CLOSES OFF AND RETROGRADES TOWARD THE MID SECTION OF THE COUNTRY BY THE MIDDLE OF NEXT WEEK. THE AIRMASS WILL BECOME LOADED WITH MOISTURE AS A DEEP-LAYERED S/SW FLOW BECOMES ESTABLISHED BETWEEN THE RIDGE OVER THE WESTERN ATLANTIC AND THE UPPER TROF. THE BEST CHANCE FOR ORGANIZED HEAVY RAINFALL WILL BE ON SUNDAY AS LOW PRESSURE OVER THE TN AND OH VALLEYS LIFTS NORTH...SENDING A STATIONARY FRONT JUST SOUTH AND EAST OF THE AREA NORTHWARD AS A WARM FRONT. PW VALUES WILL BE AROUND 2 INCHES. THIS LOOKS TO BE A MAINLY HEAVY RAINFALL EVENT AS WIND SHEAR IS MARGINAL AND THE AIRMASS IS WARM ALOFT. SCT STRONG AND/OR SEVERE CONVECTION IS A POSSIBILITY SAT AFT/EVE...PRIMARILY NORTH AND WEST OF NYC...WHERE DEEP-LAYERED SHEAR WILL EXIST WITH THE RRQ OF THE UPPER JET LIFTING ACROSS THE HUDSON VALLEY. A LIMITING FACTOR ON SAT WILL BE A BRIEF DRYING OUT OF THE AIRMASS. EARLY NEXT WEEK...WITH THE FRONTAL BOUNDARY NORTH OF THE REGION AND THE AREA IN WARM SECTOR...CONVECTION LOOKS TO BE MAINLY DIURNAL IN NATURE. MON MAY STILL REMAIN WET AS MODEL SOLUTIONS DIVERGE WITH THE LOCATION OF THE BOUNDARY. THE 12Z ECMWF IS ACTUALLY WETTER ON MON THAN SUN...A COMPLETE OPPOSITE OF THE GFS...BUT THIS IS DUE TO A SLOWER TIMING OF THE FRONTAL WAVE. KEEP IN MIND AN AIRMASS THIS MOIST AND UNSTABLE WILL TRIGGER ISOLATED TO SCT CONVECTION ALMOST ANYTIME AND IT WILL NOT TAKE MUCH FOR SOME ORGANIZATION OF CLUSTERS TO FORM POCKETS OF HEAVY RAINFALL. THIS IS ESPECIALLY THE CASE SUN INTO MON. AS FOR TEMPS...LOOKING AT BOTH HIGHS AND LOWS RUNNING A FEW DEGREES ABOVE NORMAL. SHOULD THE AMOUNT OF CLOUD COVER FROM CONVECTION BE LESS...DAYTIME HIGHS COULD BE SEVERAL DEGREES WARMER THAN CURRENTLY FORECAST. GENERALLY LOOKING FOR HIGHS 80 TO 85...AND LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... LOW PRESSURE PASSES TO THE WEST TONIGHT AS IT DRIFTS NORTH. AN ASSOCIATED FRONTAL BOUNDARY STALLS OVER THE AREA ON FRIDAY. BAND OF SHOWERS WITH EMBEDDED TSTMS EXPECTED TO SHIFT IN FROM THE SOUTH AND ENTER THE CITY AREA TERMINALS 01-03Z. COVERAGE OF EMBEDDED TSTMS EXPECTED TO DIMINISH AS IT ENTERS A MORE STABLE AIRMASS IN PLACE...SO TEMPO TSTMS IN TAFS. VFR TO MVFR BEFORE MIDNIGHT...THEN MVFR TO IFR THEREAFTER. SHRA STILL POSSIBLE AFTER MIDNIGHT. SE WINDS 10-15KT THIS EVENING BCMG S-SW OVERNIGHT. FOR FRIDAY...SCT SHRA AND TSTMS. BETTER OVERALL CHANCES IN THE AFTN. VFR AND SW GUSTS AROUND 20 KT DEVELOPING BY AROUND NOON. 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) KEWR FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. MVFR CIGS POSSIBLE BEFORE MIDNIGHT. KJFK FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. IFR CIGS POSSIBLE BEFORE MIDNIGHT. KLGA FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. MVFR CIGS POSSIBLE BEFORE MIDNIGHT. KTEB FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. MVFR CIGS POSSIBLE BEFORE MIDNIGHT. KHPN FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. KISP FCSTER COMMENTS: CHC OF A TSTM AFTER MIDNIGHT. .OUTLOOK FOR 00Z SAT THROUGH TUESDAY... .FRI-TUE...SUB VFR POSSIBLE AT TIMES WITH PERIODS OF SHOWERS AND TSTMS. && .MARINE... DENSE FOG ADVY ISSUEDC FOR THE ERN WATERS THRU TNGT. OTHERWISE...SCA ON THE OCEAN WITH BUILDING SEAS THRU FRI. S/SW FLOW CONTINUES THROUGH FRIDAY NIGHT...BUT WINDS ARE EXPECTED TO BE BELOW SCA LEVELS. SCA SOUTHERLY SWELLS SHOULD CONTINUE THROUGH. HAVE CONTINUED TO UNDERCUT WNA GUIDANCE BY 1-2 FT BASED ON GUIDANCE TREND AND ITS PERFORMANCE THIS SUMMER. POTENTIAL EXISTS FOR AN EXTENDED PERIOD OF HAZARDOUS OCEAN SEAS VIA PERSISTENT LONG FETCH SOUTHERLY FLOW. WINDS ARE EXPECTED TO STAY BELOW CRITERIA. UNDERCUT WAVEWATCH BY A ABOUT A FOOT ON THE OCEAN WATERS FOR MUCH OF THE PERIOD. && .HYDROLOGY... PATTERN INTO TONIGHT CONTINUES TO LOOK CONDUCIVE TO BANDS OF HEAVY RAIN SHOWERS AND THUNDERSTORMS TRAINING OVER THE SAME AREA...WHICH WOULD CAUSE URBAN AND SMALL STREAM FLASH FLOODING. ON AVERAGE 1/2 TO 1 1/2 INCHES OF RAINFALL EXPECTED ACROSS LI AND CT...WITH 1 1/2 TO 2 1/2 INCHES OF RAINFALL ACROSS NE NJ AND THE LOWER HUDSON VALLEY. THE HIGHER AMOUNTS IN BOTH AREAS WILL BE TO THE N AND W. LOCALLY HIGHER AMOUNTS ARE LIKELY IN THE PATH OF TRAINING ACTIVITY. RAINFALL RATES OF 2 TO 3 INCHES PER HOUR HAVE BEEN OBSERVED WITH THE STRONGER THUNDERSTORMS THIS AFTERNOON. NEEDLESS TO SAY IF THIS TYPE OF ACTIVITY TRAINS OVER AN AREA FOR AN HOUR...URBAN AND SMALL STREAM FLASH FLOODING WILL OCCUR. THE MAIN THREAT FOR URBAN FLASH FLOODING LOOKS TO BE THROUGH 06Z ACROSS THE WESTERN 1/2 OF THE CWA...AND THROUGH AROUND DAYBREAK ACROSS LI/CT. SMALL STREAMS COULD CONTINUE RISING INTO FRIDAY MORNING. MEANWHILE...MAIN STEM RIVERS WILL SEE RISES...BUT THEY ARE EXPECTED TO REMAIN WELL WITHIN THEIR BANKS. WITH SOME UNCERTAINTY ON THE EVOLUTION OF CONVECTION ON FRIDAY...WILL CONTINUE FLASH FLOOD WATCH UNTIL 6 PM FRIDAY AND LET SUBSEQUENT SHIFTS TAKE DOWN IF NEEDED. ADDITIONAL BOUTS OF HEAVY SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS WEEKEND INTO EARLY NEXT WEEK...POSING ADDITIONAL THREATS FOR FLOODING. FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CTZ005>012. NY...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ067>075- 078>081-176>179. NJ...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NJZ002-004-006- 103>108. MARINE...DENSE FOG ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ330-340-345- 350. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...NV NEAR TERM...JMC SHORT TERM...NV LONG TERM...DW AVIATION...JC MARINE...JMC/NV/DW HYDROLOGY...NV/DW
AREA FORECAST DISCUSSION
NWS NEW YORK NY
811 PM EDT THU JUN 27 2013 .SYNOPSIS... SURFACE LOW PRESSURE ACROSS SOUTHEASTERN PENNSYLVANIA WILL MOVE SLOWLY NORTH THROUGH EASTERN NEW YORK TONIGHT INTO FRIDAY. A SERIES OF LOW PRESSURE SYSTEMS WILL THEN IMPACT THE REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. BERMUDA HIGH PRESSURE STRENGTHENS AND BUILDS BACK TOWARD THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... SLOWED POPS BASED ON RADAR AND STLT WITH THE 730 UPDATE. INCLUDED FOG IN THE FCST WITH DENSE FOG REPORTED IN NANTUCKET AND 69/69 AT BUOY 44017. WESTHAMPTON AND GROTON ALREADY REPORTING BR. BEST FLOODING CHC APPEARS TO BE ACROSS WRN ZONES WITH RR QUAD OF H2 JET. POPULATED QPF WITH 00Z HPC NUMBERS...BUT BUMPED THEM UP SIGNIFICANTLY THRU 6Z TO REFLECT THE HIGH MOISTURE CONTENT CONVECTIVE ENVIRONMENT. OTHERWISE... SHORTWAVE TROUGH OVER CENTRAL PA WILL CONTINUE TO PIVOT NE THROUGH THIS EVENING. MODELS ARE INDICATING THAT THIS SHORTWAVE MAY BE SHEARING A BIT AS IT PIVOTS THROUGH AND GETS ABSORBED INTO AN UPPER LOW DIGGING INTO THE GREAT LAKES. AT THE SURFACE...LOW PRESSURE OVER SERN PA WILL SLIDE NE THROUGH EASTERN NY TONIGHT. APPROACHING UPPER LEVEL SUPPORT AND LLJ ENERGY SHOULD ALLOW FOR INCREASING SHOWER AND THUNDERSTORM DEVELOPMENT ALONG THE SEABREEZE BOUNDARY AND HIGHER ELEVATIONS OF NE NJ AND THE LOWER HUDSON VALLEY THROUGH LATE THIS AFTERNOON. THEN AS THE SHORTWAVE AXIS/SURFACE LOW APPROACH...WOULD EXPECT INCREASING TSTM ACTIVITY ACROSS SE PA/DE/S NY TO LIFT INTO THE LOWER HUDSON VALLEY...NE NJ...NYC METRO AND SW CT THIS EVENING. WITH MARGINAL TO MODERATE INSTABILITY ACROSS OUR FAR WESTERN AREAS AREA...MODEST SHEAR...AND INCREASING HELICITY A FEW STRONG TO SEVERE STORMS ARE POSSIBLE THROUGH THIS EVENING...MAINLY WEST OF THE HUDSON RIVER. THE LIMITING FACTOR WILL BE WANING INSTABILITY...BUT COULD BE OVERCOME BY INCREASING SYNOPTIC SUPPORT. STRONG WINDS WOULD BE THE MAIN SEVERE THREAT...BUT CAN NOT RULE OUT AN ISOLATED WEAK TORNADO WITH ANY ROTATING STORMS. BASED ON PWATS AROUND 2 INCHES...GOOD SYNOPTIC SUPPORT...AND WIND FIELDS INDICATIVE OF TRAINING CELLS...MAIN OVERALL THREAT CONTINUES TO BE FLASH FLOODING...WHICH SHOULD PEAK THIS EVENING ACROSS THE WESTERN 1/2 OF THE CWA. THEN AS THE SYNOPTIC FORCING CONTINUES TO PUSH EAST LATE THIS EVENING INTO THE OVERNIGHT...THE THREAT FOR HEAVY SHOWERS AND TSTMS WILL LIKELY SHIFT EAST ACROSS LI AND CT...WITH THE THREAT FOR URBAN FLASH FLOODING DIMINISHING TO THE WEST. THERE IS SOME UNCERTAINTY IN HOW WIDESPREAD HEAVY SHOWER/TSRA ACTIVITY WILL BE ACROSS LI AND CT OVERNIGHT. DUE TO THE WEAKENING OF THE SURFACE TROUGH AS THE SHORTWAVE SHEARS NW...THERE WILL BE NO CLEAR CUT CONVERGENCE BOUNDARY TO FOCUS CONVECTION. WITH THIS SAID THE SHRA/TSTM ACTIVITY COULD BE MORE STREAKY IN NATURE ACROSS LI/CT TONIGHT...WITH FRICTIONAL CONVERGENCE LOCALLY ENHANCING ACTIVITY. THIS IS SUPPORTED BY SOME OF THE HIGH RES MODEL OUTPUT. WITH DEEP MOISTURE AXIS ADVECTING OVER THE REGION...MARGINAL INSTABILITY...AND STRONG LLJ SUPPORT...THE FLASH FLOODING THREAT WILL EXIST WHERE THESE RAIN BANDS DEVELOP...BUT COVERAGE MAY NOT BE AS WIDESPREAD AS ACROSS WESTERN PORTIONS OF THE AREA. HEAVIEST RAIN SHOWER/TSRA ACTIVITY LIKELY PUSHES EAST OF THE REGION BY DAYBREAK AS SHORTWAVE AND LLJ PIVOT N AND E. SEE HYDROLOGY SECTION FOR MORE ON FLOODING THREAT. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... THE GREAT LAKES UPPER LOW CONTINUES TO DEEPEN INTO THE NORTHEAST DURING THIS TIME PERIOD. DRYING CONDITIONS ARE LIKELY FRIDAY MORNING ACROSS WESTERN SECTIONS IN THE WAKE OF THE SHORTWAVE...WITH PARTIAL CLEARING. FAR EASTERN SECTIONS WILL LIKELY SEE MORE IN THE WAY OF CLOUD COVER...AS THEY WILL BE ON THE FRINGE OF THE TROPICAL CONVEYOR BELT. TIMING OF SHORTWAVES AROUND THE UPPER LOW WILL DETERMINE EXACT TIMING OF ADDITIONAL SHRA/TSRA ACTIVITY FRI AFT/FRI NIGHT...BUT HIGHEST PROBABILITY WILL LIKELY BE ACROSS INTERIOR FRI AFT/EVE WITH DIURNAL HEATING. FLASH FLOOD THREAT APPEARS TO BE LOWER ON FRIDAY AS PWATS DROP TO 1.25 TO 1.5 INCHES IN THE WAKE OF THE SHORTWAVE. MARGINAL INSTABILITY AND SHEAR ALSO INDICATE THAT STRONG TO SEVERE STORMS WOULD BE ISOLATED...BUT THIS WILL ULTIMATELY BE DETERMINED BY STRENGTH OF THE NEXT SHORTWAVE AND AMOUNT OF HEATING. && .LONG TERM /SATURDAY THROUGH THURSDAY/... UNSETTLED...MUGGY AND WARM CONDITIONS WILL BE THE RULE FOR MUCH OF THE PERIOD AS AN UPPER TROF OVER THE NE AND OH VALLEY STATES THIS WEEKEND CLOSES OFF AND RETROGRADES TOWARD THE MID SECTION OF THE COUNTRY BY THE MIDDLE OF NEXT WEEK. THE AIRMASS WILL BECOME LOADED WITH MOISTURE AS A DEEP-LAYERED S/SW FLOW BECOMES ESTABLISHED BETWEEN THE RIDGE OVER THE WESTERN ATLANTIC AND THE UPPER TROF. THE BEST CHANCE FOR ORGANIZED HEAVY RAINFALL WILL BE ON SUNDAY AS LOW PRESSURE OVER THE TN AND OH VALLEYS LIFTS NORTH...SENDING A STATIONARY FRONT JUST SOUTH AND EAST OF THE AREA NORTHWARD AS A WARM FRONT. PW VALUES WILL BE AROUND 2 INCHES. THIS LOOKS TO BE A MAINLY HEAVY RAINFALL EVENT AS WIND SHEAR IS MARGINAL AND THE AIRMASS IS WARM ALOFT. SCT STRONG AND/OR SEVERE CONVECTION IS A POSSIBILITY SAT AFT/EVE...PRIMARILY NORTH AND WEST OF NYC...WHERE DEEP-LAYERED SHEAR WILL EXIST WITH THE RRQ OF THE UPPER JET LIFTING ACROSS THE HUDSON VALLEY. A LIMITING FACTOR ON SAT WILL BE A BRIEF DRYING OUT OF THE AIRMASS. EARLY NEXT WEEK...WITH THE FRONTAL BOUNDARY NORTH OF THE REGION AND THE AREA IN WARM SECTOR...CONVECTION LOOKS TO BE MAINLY DIURNAL IN NATURE. MON MAY STILL REMAIN WET AS MODEL SOLUTIONS DIVERGE WITH THE LOCATION OF THE BOUNDARY. THE 12Z ECMWF IS ACTUALLY WETTER ON MON THAN SUN...A COMPLETE OPPOSITE OF THE GFS...BUT THIS IS DUE TO A SLOWER TIMING OF THE FRONTAL WAVE. KEEP IN MIND AN AIRMASS THIS MOIST AND UNSTABLE WILL TRIGGER ISOLATED TO SCT CONVECTION ALMOST ANYTIME AND IT WILL NOT TAKE MUCH FOR SOME ORGANIZATION OF CLUSTERS TO FORM POCKETS OF HEAVY RAINFALL. THIS IS ESPECIALLY THE CASE SUN INTO MON. AS FOR TEMPS...LOOKING AT BOTH HIGHS AND LOWS RUNNING A FEW DEGREES ABOVE NORMAL. SHOULD THE AMOUNT OF CLOUD COVER FROM CONVECTION BE LESS...DAYTIME HIGHS COULD BE SEVERAL DEGREES WARMER THAN CURRENTLY FORECAST. GENERALLY LOOKING FOR HIGHS 80 TO 85...AND LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... LOW PRESSURE PASSES TO THE WEST TONIGHT AS IT DRIFTS NORTH. AN ASSOCIATED FRONTAL BOUNDARY STALLS OVER THE AREA ON FRIDAY. BAND OF SHOWERS WITH EMBEDDED TSTMS EXPECTED TO SHIFT IN FROM THE SOUTH AND ENTER THE CITY AREA TERMINALS 01-03Z. COVERAGE OF EMBEDDED TSTMS EXPECTED TO DIMINISH AS IT ENTERS A MORE STABLE AIRMASS IN PLACE...SO TEMPO TSTMS IN TAFS. VFR TO MVFR BEFORE MIDNIGHT...THEN MVFR TO IFR THEREAFTER. SHRA STILL POSSIBLE AFTER MIDNIGHT. SE WINDS 10-15KT THIS EVENING BCMG S-SW OVERNIGHT. FOR FRIDAY...SCT SHRA AND TSTMS. BETTER OVERALL CHANCES IN THE AFTN. VFR AND SW GUSTS AROUND 20 KT DEVELOPING BY AROUND NOON. 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) KEWR FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. MVFR CIGS POSSIBLE BEFORE MIDNIGHT. KJFK FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. IFR CIGS POSSIBLE BEFORE MIDNIGHT. KLGA FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. MVFR CIGS POSSIBLE BEFORE MIDNIGHT. KTEB FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. MVFR CIGS POSSIBLE BEFORE MIDNIGHT. KHPN FCSTER COMMENTS: A GUST TO 35-40 KT POSSIBLE IN/NEAR TSTM THIS EVENING. KISP FCSTER COMMENTS: CHC OF A TSTM AFTER MIDNIGHT. .OUTLOOK FOR 00Z SAT THROUGH TUESDAY... .FRI-TUE...SUB VFR POSSIBLE AT TIMES WITH PERIODS OF SHOWERS AND TSTMS. && .MARINE... A STRENGTHENING SOUTHERLY FLOW IS EXPECTED TO DEVELOP MARGINAL SCA SEAS OVER THE OCEAN WATERS TONIGHT. MARGINAL SCA GUSTS ARE POSSIBLE AS A LOW LEVEL JET MOVES OVER THE AREA TONIGHT...AND PASSES EAST FRIDAY MORNING. S/SW FLOW CONTINUES THROUGH FRIDAY NIGHT...BUT WINDS ARE EXPECTED TO BE BELOW SCA LEVELS. SCA SOUTHERLY SWELLS SHOULD CONTINUE THROUGH. HAVE CONTINUED TO UNDERCUT WNA GUIDANCE BY 1-2 FT BASED ON GUIDANCE TREND AND ITS PERFORMANCE THIS SUMMER. POTENTIAL EXISTS FOR AN EXTENDED PERIOD OF HAZARDOUS OCEAN SEAS VIA PERSISTENT LONG FETCH SOUTHERLY FLOW. WINDS ARE EXPECTED TO STAY BELOW CRITERIA. UNDERCUT WAVEWATCH BY A ABOUT A FOOT ON THE OCEAN WATERS FOR MUCH OF THE PERIOD. && .HYDROLOGY... PATTERN INTO TONIGHT CONTINUES TO LOOK CONDUCIVE TO BANDS OF HEAVY RAIN SHOWERS AND THUNDERSTORMS TRAINING OVER THE SAME AREA...WHICH WOULD CAUSE URBAN AND SMALL STREAM FLASH FLOODING. ON AVERAGE 1/2 TO 1 1/2 INCHES OF RAINFALL EXPECTED ACROSS LI AND CT...WITH 1 1/2 TO 2 1/2 INCHES OF RAINFALL ACROSS NE NJ AND THE LOWER HUDSON VALLEY. THE HIGHER AMOUNTS IN BOTH AREAS WILL BE TO THE N AND W. LOCALLY HIGHER AMOUNTS ARE LIKELY IN THE PATH OF TRAINING ACTIVITY. RAINFALL RATES OF 2 TO 3 INCHES PER HOUR HAVE BEEN OBSERVED WITH THE STRONGER THUNDERSTORMS THIS AFTERNOON. NEEDLESS TO SAY IF THIS TYPE OF ACTIVITY TRAINS OVER AN AREA FOR AN HOUR...URBAN AND SMALL STREAM FLASH FLOODING WILL OCCUR. THE MAIN THREAT FOR URBAN FLASH FLOODING LOOKS TO BE THROUGH 06Z ACROSS THE WESTERN 1/2 OF THE CWA...AND THROUGH AROUND DAYBREAK ACROSS LI/CT. SMALL STREAMS COULD CONTINUE RISING INTO FRIDAY MORNING. MEANWHILE...MAIN STEM RIVERS WILL SEE RISES...BUT THEY ARE EXPECTED TO REMAIN WELL WITHIN THEIR BANKS. WITH SOME UNCERTAINTY ON THE EVOLUTION OF CONVECTION ON FRIDAY...WILL CONTINUE FLASH FLOOD WATCH UNTIL 6 PM FRIDAY AND LET SUBSEQUENT SHIFTS TAKE DOWN IF NEEDED. ADDITIONAL BOUTS OF HEAVY SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS WEEKEND INTO EARLY NEXT WEEK...POSING ADDITIONAL THREATS FOR FLOODING. FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CTZ005>012. NY...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ067>075- 078>081-176>179. NJ...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NJZ002-004-006- 103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...NV NEAR TERM...JMC/NV SHORT TERM...NV LONG TERM...DW AVIATION...JC MARINE...NV/DW HYDROLOGY...NV/DW
AREA FORECAST DISCUSSION
NWS ALBANY NY
759 PM EDT THU JUN 27 2013 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL MOVE FROM PENNSYLVANIA ACROSS UPSTATE NEW YORK TONIGHT...ALLOWING FOR PERIODS OF HEAVY RAIN AND THUNDERSTORMS...WITH THE POTENTIAL FOR FLOODING. THE LOW PRESSURE SYSTEM WILL MOVE SLOWLY NORTHEAST TOWARDS SOUTHERN QUEBEC TOMORROW INTO SATURDAY WITH HUMID CONDITIONS...AND CONTINUED CHANCES OF SHOWERS AND THUNDERSTORMS INTO NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... ...FLOOD WATCH CONTINUES THROUGH FRIDAY AFTERNOON... AS OF 750 PM EDT...STEADY RAINFALL STILL REMAINS JUST TO THE WEST OF THE FORECAST AREA OVER CENTRAL NY...NE PA...AND NORTHERN NJ AT THIS TIME...ALTHOUGH A FEW SHOWERS AND THUNDERSTORMS HAVE FLARED UP FROM TIME TO TIME ACROSS VARIOUS PARTS OF THE AREA EARLY THIS EVENING. INSTABILITY WILL START TO WANE AS CLOUDS HAVE INCREASED AND DAYTIME HEATING IS LOST. STILL SBCAPE VALUES OF AROUND 500-1000 J/KG STILL EXIST AT THIS HOUR SO SOME CELLS WILL PRODUCE LIGHTNING AND DOWNPOURS. THE STEADIER RAIN WITH EMBEDDED CONVECTION SHOULD MOVE INTO THE AREA FROM SOUTHWEST TO NORTHEAST LATER THIS EVENING AND INTO THE OVERNIGHT HOURS. AT 500 HPA...A SHARP SHORTWAVE TROUGH IS LOCATED OVER CENTRAL PA AND CONTINUES TO LIFT TOWARDS THE NORTHEAST. AT THE SURFACE...AN UNUSUALLY STRONG LOW FOR MID JUNE /2 TO 4 STD BELOW NORMAL/ IS LOCATED NEAR READING PA. STRONG SOUTHERLY FLOW AHEAD OF THIS SYSTEM IS ADVECTING PLENTY OF MOISTURE INTO THE REGION. PWAT VALUES ARE EXPECTED TO REACH CLOSE TO 2.00 INCHES...WHICH IS ABOUT 2-3 STD ABOVE NORMAL. CLOUDS WILL CONTINUE TO THICKEN THROUGH THE EVENING EVENING AS THE SYSTEM MOVES TOWARDS THE AREA. THE LOW PRESSURE WILL MOVE FROM THE POCONOS AND CATSKILLS TOWARDS THE SARATOGA REGION BY SUNRISE...BRINGING A STEADY SHIELD OF RAIN ACROSS OUR AREA OVERNIGHT. OUR LOCAL HIRES WRF AND THE 3KM HRRR ALL SHOW THIS FAIRLY CLEARLY. THIS SYSTEM HAS PRODUCED HEAVY RAIN UPSTREAM ACROSS WESTERN/CENTRAL PA...AND ITS EXPECTED TO DO THE SAME OVERNIGHT AS IT MOVES ACROSS OUR AREA. RAINFALL RATES OF ONE HALF TO ONE INCH PER HOUR WILL BE POSSIBLE AT TIMES...WITH LOCALLY HEAVY AMOUNTS BRIEFLY POSSIBLE AS WELL. THERE IS A POSSIBILITY OF SOME FLASH FLOODING TONIGHT...AS WELL AS TYPICAL URBAN...SMALL STREAM AND POOR DRAINAGE FLOODING. /SEE OUR HYDRO SECTION FOR MORE DETAILS INCLUDING EXPECTED QPF VALUES/. THE BEST CHC OF SEEING THUNDER WILL BE ON THE LEADING EDGE OF THIS STEADY RAIN AS WELL...BASED ON UPSTREAM TRENDS CURRENTLY ONGOING ACROSS NORTHEAST PA AND INTO NEW JERSEY. STEADY RAIN WILL START TO TAPER OFF ACROSS SOUTHERN AREAS TOWARDS DAYBREAK...BUT IT SHOULD STILL BE RAINING FAIRLY STEADILY FROM THE CAPITAL REGION ON NORTH. MIN TEMPS WILL REMAIN MILD AND MUGGY...WITH READING IN THE 60S TO LOW 70S ACROSS THE ENTIRE AREA. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... STEADY RAIN WILL CONTINUE ACROSS NORTHERN AND EASTERN AREAS DURING THE MORNING HOURS...BUT IT SHOULD START TO TAPER OFF BY NOON. AT THIS POINT...THE CONCERN WILL BECOME FOR RIVER FLOODING...AS ALL THE RUNOFF FROM THE OVERNIGHT RAIN REACHES THE MAIN STEM RIVERS. MEANWHILE...SOME ADDITIONAL RAIN SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE IN THE AFTN AS THE WHOLE UPPER TROUGH CLOSES OFF TO OUR WEST AND SLOWLY SPINS. SKIES WILL BE FAIRLY CLOUDY FOR MUCH OF THE DAY...WITH MAX TEMPS COOLER THAN RECENT DAYS /MAINLY IN THE 70S WITH SOME LOW 80S IN FAR SOUTHERN AREAS/. IT WILL REMAIN WET AND UNSETTLED FOR FRI NIGHT THROUGH SAT NIGHT AS THE CLOSED SLOW MOVING UPPER TROUGH REMAINS TO OUR WEST AND A STRONG JET REMAINS OVERHEAD. THERE WILL BE A CONTINUED THREAT FOR SHOWERS AND THUNDERSTORMS...WITH THE BEST CHC OF THUNDER DURING THE AFTN AND EVENING HOURS. IT LOOKS FAIRLY CLOUDY...ALTHOUGH SOME BREAKS OF SUN ARE POSSIBLE ON SAT AFTN FOR EASTERN/SOUTHERN AREAS. MIN TEMPS WILL CONTINUE TO BE MILD WITH MAINLY 60S. DAYTIME HIGHS ON SAT WILL RANGE FROM THE MID 70S TO MID 80S...WITH THE WARMEST TEMPS IN THOSE AREAS THAT GET SOME BREAKS OF SUN BETWEEN SHOWERS AND STORMS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A RATHER REPETITIVE FORECAST IS SHAPING UP FOR THE DURATION OF THE LONG TERM PERIOD. MODEL GUIDANCE IN RELATIVELY GOOD AGREEMENT DURING THIS TIME WITH REGARDS TO THE LARGE SCALE FEATURES. LATEST 12Z MODELS STILL SHOWS A BLOCKING PATTERN WILL BE IN PLACE ACROSS MUCH OF NORTH AMERICA...WITH A PERSISTENT BERMUDA HIGH OVER THE WESTERN ATLANTIC AND A TROUGH OVER THE GREAT LAKES AND MIDWEST WITH A STRONG RIDGE OVER THE WESTERN CONUS. THIS SYNOPTIC SET UP WILL PUT THE NORTHEASTERN STATES IN A GOOD POSITION OF POSITIVE 850-700 HPA SOUTH AND SOUTHWEST WIND FLOW ANOMALIES OF AROUND 2 TO 3 S.D. FLOWING RIGHT OVER THE REGION BRINGING GULF OF MEXICO AND SOUTHERN ATLANTIC MOISTURE INTO THE REGION. THIS IN RETURN WILL ALLOW WEAK DISTURBANCES TO RIDE ALONG THE UPPER LEVEL WIND FLOW BETWEEN THE TWO LARGE SYNOPTIC FEATURES AND CAUSE PERSISTENT CHANCES OF SHOWERS AND EVEN A FEW ISOLATED THUNDERSTORMS WITH THIS PERTURBATION PATTERN THROUGHOUT THE LONG TERM PERIOD. ALONG WITH WIND ANOMALIES...HEIGHT ANOMALIES OF -1 TO -2 S.D. ASSOCIATED WITH THE DIGGING TROUGH TO THE WEST OF THE REGION AND HEIGHT ANOMALIES WITH THE HIGH PRESSURE IN THE ATLANTIC OF 1.5 TO 2 S.D. ACCORDING TO THE LATEST MODELS ALONG WITH WEAK WINDS ALOFT...THIS PATTERN WILL ALMOST BE STATIONARY THROUGH THE EXTENDED PERIOD THIS PATTERN WILL CONTINUE TO RESULT MOSTLY CLOUDY SKIES WITH HUMID CONDITIONS. HIGHS SUNDAY THROUGH THURSDAY WILL GENERALLY BE IN THE MID 70S TO MID 80S WITH LOW TEMPERATURES RANGING FROM THE LOW 60S TO UPPER 60S THROUGHOUT THIS PERIOD. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... CONDITIONS WILL DETERIORATE LATER THIS EVENING INTO THE OVERNIGHT HOURS...AS AN ANOMALOUSLY STRONG LOW PRESSURE SYSTEM MOVES INTO THE AREA FROM PA. THIS WILL SPREAD A SHIELD OF STEADY RAINFALL WITH EMBEDDED CONVECTIVE ELEMENTS OF HEAVIER RAIN. THE STEADIER RAIN SHOULD MOVE IN ACROSS THE TERMINALS BETWEEN 02Z-03Z. UNTIL THEN...WATCHING A SMALL CLUSTER OF THUNDERSTORMS WITH DOWNPOURS THAT HAVE DEVELOPED SOUTH OF KALB AND ARE APPROACHING THE TERMINAL. IT APPEARS AS THOUGH THE STRONGEST PART OF THE STORM WILL PASS BY TO THE WEST OF THE AIRPORT...BUT A FEW MODERATE BURSTS OF RAIN AND SOME THUNDER ARE STILL POSSIBLE. SO WILL MENTION A TEMPO FOR THUNDER AND MVFR CONDITIONS THERE. OTHERWISE...CONDITIONS WILL DETERIORATE FROM VFR TO MVFR LATER THIS EVENING...WITH PERIODS OF IFR DEVELOPING WITHIN ANY HEAVIER RAINFALL. WILL MENTION TEMPO GROUPS BETWEEN EITHER 03Z-06Z FOR OCCASIONAL IFR FOR KPOU/KALB...AND 04Z-06Z FOR KPSF/KGFL. CONDITIONS ARE EXPECTED TO VARY BETWEEN IFR/MVFR FOR THE REST OF THE OVERNIGHT HOURS AS RAINFALL CONTINUES. THE RAIN WILL TAPER OFF TO SHOWERS BY 12Z...WITH CONDITIONS SLOWLY IMPROVING TO MVFR THEN POSSIBLY VFR IF ENOUGH DRYING OCCURS BY 16Z-18Z FRIDAY. WINDS WILL BE GENERALLY EAST-NORTHEAST AROUND 3 TO 6 KT TONIGHT... BECOMING SOUTHERLY FRIDAY AROUND 5 TO 10 KT. OUTLOOK... FRI NIGHT-TUE...VFR/MVFR. CHC SHRA/TSRA. POSSIBLE LATE NIGHT AND OR EARLY MORNING FOG/LOW STRATUS WITH IFR. && .FIRE WEATHER... NO FIRE WEATHER ISSUES AT THIS TIME DUE TO PERSISTENT WET CONDITIONS. HEAVY RAIN WILL BE POSSIBLE TONIGHT INTO TOMORROW MORNING...WITH ADDITIONAL SHOWERS POSSIBLE THROUGH MUCH OF NEXT WEEK. RH VALUES WILL REMAIN RATHER HIGH RIGHT THROUGH THE WEEKEND. && .HYDROLOGY... A FLOOD WATCH REMAINS IN EFFECT THROUGH FRIDAY AFTERNOON. THERE WILL BE A THREAT FOR BOTH FLASH FLOODING AND MAIN STEM RIVER FLOODING OVER THE NEXT SEVERAL DAYS. A STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA TONIGHT INTO THE DAY ON FRIDAY. WITH PWATS VALUES EXPECTED TO EXCEED 2 STD ABOVE NORMAL...AND SURFACE DEWPOINTS IN THE 60S TO NEAR 70...HEAVY RAINFALL IS LIKELY. A RAIN SHIELD ASSOCIATED WITH THIS STORM WILL MOVE ACROSS THE AREA FROM SOUTH TO NORTH BEGINNING THIS EVENING. EMBEDDED CONVECTIVE ELEMENTS WILL ALLOW FOR LOCALLY HEAVY RAINFALL WITHIN A STRATIFORM RAIN SHIELD. INITIALLY...THERE WILL BE A CONCERN FOR LOCALIZED FLASH FLOODING DUE TO THE EMBEDDED CONVECTION. THIS WILL EVENTUALLY TRANSITION TO FLOODING FOR THE MAIN STEMS RIVERS FRIDAY MORNING INTO THE AFTERNOON. BASIN AVERAGE RAINFALL IS FORECASTED FROM 1.5 TO 3 INCHES...ALTHOUGH HIGHER TERRAIN AREAS OF THE CATSKILLS AND ADIRONDACKS COULD SEE IN EXCESS OF 3 INCHES. ISOLATED POINT RAINFALL TOTALS OF UP TO 5 INCHES CANNOT BE RULED OUT ACROSS THE HIGHEST TERRAIN OF THE EASTERN CATSKILLS AND THE ERN DACKS. THE AREA MOST SUSCEPTIBLE TO MAIN STEM RIVER FLOODING WILL LIKELY BE THE MOHAWK RIVER BASIN BASED ON THE LATEST NERFC HYDROGRAPHS. THIS AREA HAS SEEN A LOT OF RAIN LATELY...AND SOILS ARE RATHER SATURATED. THE NERFC HAS ALREADY FORECASTED SEVERAL POINTS TO RISE ABOVE FLOOD STAGE DURING THE DAY FRIDAY...MAINLY ACROSS THE NORTHERN HALF OF THE HSA. HOWEVER...THE CATSKILL BASINS WILL NEED TO BE MONITORED CLOSELY AS WELL. 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...FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CTZ001-013. NY...FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ032-033-038>043- 047>054-058>061-063>066-082>084. MA...FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR MAZ001-025. VT...FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR VTZ013>015. && $$ SYNOPSIS...FRUGIS NEAR TERM...FRUGIS/JPV SHORT TERM...FRUGIS LONG TERM...LFM AVIATION...JPV FIRE WEATHER...FRUGIS HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
741 PM EDT THU JUN 27 2013 .SYNOPSIS... SURFACE LOW PRESSURE ACROSS SOUTHEASTERN PENNSYLVANIA WILL MOVE SLOWLY NORTH THROUGH EASTERN NEW YORK TONIGHT INTO FRIDAY. A SERIES OF LOW PRESSURE SYSTEMS WILL THEN IMPACT THE REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. BERMUDA HIGH PRESSURE STRENGTHENS AND BUILDS BACK TOWARD THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... SLOWED POPS BASED ON RADAR AND STLT WITH THE 730 UPDATE. INCLUDED FOG IN THE FCST WITH DENSE FOG REPORTED IN NANTUCKET AND 69/69 AT BUOY 44017. WESTHAMPTON AND GROTON ALREADY REPORTING BR. BEST FLOODING CHC APPEARS TO BE ACROSS WRN ZONES WITH RR QUAD OF H2 JET. POPULATED QPF WITH 00Z HPC NUMBERS...BUT BUMPED THEM UP SIGNIFICANTLY THRU 6Z TO REFLECT THE HIGH MOISTURE CONTENT CONVECTIVE ENVIRONMENT. OTHERWISE... SHORTWAVE TROUGH OVER CENTRAL PA WILL CONTINUE TO PIVOT NE THROUGH THIS EVENING. MODELS ARE INDICATING THAT THIS SHORTWAVE MAY BE SHEARING A BIT AS IT PIVOTS THROUGH AND GETS ABSORBED INTO AN UPPER LOW DIGGING INTO THE GREAT LAKES. AT THE SURFACE...LOW PRESSURE OVER SERN PA WILL SLIDE NE THROUGH EASTERN NY TONIGHT. APPROACHING UPPER LEVEL SUPPORT AND LLJ ENERGY SHOULD ALLOW FOR INCREASING SHOWER AND THUNDERSTORM DEVELOPMENT ALONG THE SEABREEZE BOUNDARY AND HIGHER ELEVATIONS OF NE NJ AND THE LOWER HUDSON VALLEY THROUGH LATE THIS AFTERNOON. THEN AS THE SHORTWAVE AXIS/SURFACE LOW APPROACH...WOULD EXPECT INCREASING TSTM ACTIVITY ACROSS SE PA/DE/S NY TO LIFT INTO THE LOWER HUDSON VALLEY...NE NJ...NYC METRO AND SW CT THIS EVENING. WITH MARGINAL TO MODERATE INSTABILITY ACROSS OUR FAR WESTERN AREAS AREA...MODEST SHEAR...AND INCREASING HELICITY A FEW STRONG TO SEVERE STORMS ARE POSSIBLE THROUGH THIS EVENING...MAINLY WEST OF THE HUDSON RIVER. THE LIMITING FACTOR WILL BE WANING INSTABILITY...BUT COULD BE OVERCOME BY INCREASING SYNOPTIC SUPPORT. STRONG WINDS WOULD BE THE MAIN SEVERE THREAT...BUT CAN NOT RULE OUT AN ISOLATED WEAK TORNADO WITH ANY ROTATING STORMS. BASED ON PWATS AROUND 2 INCHES...GOOD SYNOPTIC SUPPORT...AND WIND FIELDS INDICATIVE OF TRAINING CELLS...MAIN OVERALL THREAT CONTINUES TO BE FLASH FLOODING...WHICH SHOULD PEAK THIS EVENING ACROSS THE WESTERN 1/2 OF THE CWA. THEN AS THE SYNOPTIC FORCING CONTINUES TO PUSH EAST LATE THIS EVENING INTO THE OVERNIGHT...THE THREAT FOR HEAVY SHOWERS AND TSTMS WILL LIKELY SHIFT EAST ACROSS LI AND CT...WITH THE THREAT FOR URBAN FLASH FLOODING DIMINISHING TO THE WEST. THERE IS SOME UNCERTAINTY IN HOW WIDESPREAD HEAVY SHOWER/TSRA ACTIVITY WILL BE ACROSS LI AND CT OVERNIGHT. DUE TO THE WEAKENING OF THE SURFACE TROUGH AS THE SHORTWAVE SHEARS NW...THERE WILL BE NO CLEAR CUT CONVERGENCE BOUNDARY TO FOCUS CONVECTION. WITH THIS SAID THE SHRA/TSTM ACTIVITY COULD BE MORE STREAKY IN NATURE ACROSS LI/CT TONIGHT...WITH FRICTIONAL CONVERGENCE LOCALLY ENHANCING ACTIVITY. THIS IS SUPPORTED BY SOME OF THE HIGH RES MODEL OUTPUT. WITH DEEP MOISTURE AXIS ADVECTING OVER THE REGION...MARGINAL INSTABILITY...AND STRONG LLJ SUPPORT...THE FLASH FLOODING THREAT WILL EXIST WHERE THESE RAIN BANDS DEVELOP...BUT COVERAGE MAY NOT BE AS WIDESPREAD AS ACROSS WESTERN PORTIONS OF THE AREA. HEAVIEST RAIN SHOWER/TSRA ACTIVITY LIKELY PUSHES EAST OF THE REGION BY DAYBREAK AS SHORTWAVE AND LLJ PIVOT N AND E. SEE HYDROLOGY SECTION FOR MORE ON FLOODING THREAT. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... THE GREAT LAKES UPPER LOW CONTINUES TO DEEPEN INTO THE NORTHEAST DURING THIS TIME PERIOD. DRYING CONDITIONS ARE LIKELY FRIDAY MORNING ACROSS WESTERN SECTIONS IN THE WAKE OF THE SHORTWAVE...WITH PARTIAL CLEARING. FAR EASTERN SECTIONS WILL LIKELY SEE MORE IN THE WAY OF CLOUD COVER...AS THEY WILL BE ON THE FRINGE OF THE TROPICAL CONVEYOR BELT. TIMING OF SHORTWAVES AROUND THE UPPER LOW WILL DETERMINE EXACT TIMING OF ADDITIONAL SHRA/TSRA ACTIVITY FRI AFT/FRI NIGHT...BUT HIGHEST PROBABILITY WILL LIKELY BE ACROSS INTERIOR FRI AFT/EVE WITH DIURNAL HEATING. FLASH FLOOD THREAT APPEARS TO BE LOWER ON FRIDAY AS PWATS DROP TO 1.25 TO 1.5 INCHES IN THE WAKE OF THE SHORTWAVE. MARGINAL INSTABILITY AND SHEAR ALSO INDICATE THAT STRONG TO SEVERE STORMS WOULD BE ISOLATED...BUT THIS WILL ULTIMATELY BE DETERMINED BY STRENGTH OF THE NEXT SHORTWAVE AND AMOUNT OF HEATING. && .LONG TERM /SATURDAY THROUGH THURSDAY/... UNSETTLED...MUGGY AND WARM CONDITIONS WILL BE THE RULE FOR MUCH OF THE PERIOD AS AN UPPER TROF OVER THE NE AND OH VALLEY STATES THIS WEEKEND CLOSES OFF AND RETROGRADES TOWARD THE MID SECTION OF THE COUNTRY BY THE MIDDLE OF NEXT WEEK. THE AIRMASS WILL BECOME LOADED WITH MOISTURE AS A DEEP-LAYERED S/SW FLOW BECOMES ESTABLISHED BETWEEN THE RIDGE OVER THE WESTERN ATLANTIC AND THE UPPER TROF. THE BEST CHANCE FOR ORGANIZED HEAVY RAINFALL WILL BE ON SUNDAY AS LOW PRESSURE OVER THE TN AND OH VALLEYS LIFTS NORTH...SENDING A STATIONARY FRONT JUST SOUTH AND EAST OF THE AREA NORTHWARD AS A WARM FRONT. PW VALUES WILL BE AROUND 2 INCHES. THIS LOOKS TO BE A MAINLY HEAVY RAINFALL EVENT AS WIND SHEAR IS MARGINAL AND THE AIRMASS IS WARM ALOFT. SCT STRONG AND/OR SEVERE CONVECTION IS A POSSIBILITY SAT AFT/EVE...PRIMARILY NORTH AND WEST OF NYC...WHERE DEEP-LAYERED SHEAR WILL EXIST WITH THE RRQ OF THE UPPER JET LIFTING ACROSS THE HUDSON VALLEY. A LIMITING FACTOR ON SAT WILL BE A BRIEF DRYING OUT OF THE AIRMASS. EARLY NEXT WEEK...WITH THE FRONTAL BOUNDARY NORTH OF THE REGION AND THE AREA IN WARM SECTOR...CONVECTION LOOKS TO BE MAINLY DIURNAL IN NATURE. MON MAY STILL REMAIN WET AS MODEL SOLUTIONS DIVERGE WITH THE LOCATION OF THE BOUNDARY. THE 12Z ECMWF IS ACTUALLY WETTER ON MON THAN SUN...A COMPLETE OPPOSITE OF THE GFS...BUT THIS IS DUE TO A SLOWER TIMING OF THE FRONTAL WAVE. KEEP IN MIND AN AIRMASS THIS MOIST AND UNSTABLE WILL TRIGGER ISOLATED TO SCT CONVECTION ALMOST ANYTIME AND IT WILL NOT TAKE MUCH FOR SOME ORGANIZATION OF CLUSTERS TO FORM POCKETS OF HEAVY RAINFALL. THIS IS ESPECIALLY THE CASE SUN INTO MON. AS FOR TEMPS...LOOKING AT BOTH HIGHS AND LOWS RUNNING A FEW DEGREES ABOVE NORMAL. SHOULD THE AMOUNT OF CLOUD COVER FROM CONVECTION BE LESS...DAYTIME HIGHS COULD BE SEVERAL DEGREES WARMER THAN CURRENTLY FORECAST. GENERALLY LOOKING FOR HIGHS 80 TO 85...AND LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... LOW PRESSURE APPROACHES FROM THE WEST AND MOVES TO THE NORTHWEST TONIGHT. MOSTLY VFR EXCEPT KGON. WIND DIRECTIONS ARE GENERALLY OUT OF THE ESE-SE. SPEEDS WILL BE FROM 8 TO 12 KT. AN OCCASIONAL GUST TO 15 KT CANNOT BE RULED OUT AT CITY TERMINALS THROUGH EARLY EVENING. THE LIKELIHOOD FOR SHOWERS AND THUNDERSTORMS OCCURS THIS EVENING AND CONTINUES THROUGH 05/06Z. MOSTLY SHOWERS ANTICIPATED AFTER THIS TIME...BUT AN ISOLATED THUNDERSTORM REMAINS A POSSIBILITY BUT NOT MENTIONED IN TAFS. CIGS WILL LOWER TO MVFR OR IFR LATE TONIGHT AND COULD CONTINUE INTO EARLY FRIDAY MORNING. LOW CONFIDENCE IN THE TIMING OF IMPROVEMENTS TO VFR AFTER SUNRISE. WINDS ALSO BEGIN TO SHIFT TO THE SW. 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) KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE THIS EVENING FOR DEVELOPING SHOWERS AND THUNDERSTORMS. AN OCCASIONAL GUST TO 15 KT POSSIBLE THROUGH EARLY EVENING. KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE THIS EVENING FOR DEVELOPING SHOWERS AND THUNDERSTORMS. CIGS COULD VARY BETWEEN MVFR AND VFR. AN OCCASIONAL GUST TO 15 KT POSSIBLE THROUGH EARLY EVENING. KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE THIS EVENING FOR DEVELOPING SHOWERS AND THUNDERSTORMS. AN OCCASIONAL GUST TO 15 KT POSSIBLE THROUGH EARLY EVENING. KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE THIS EVENING FOR DEVELOPING SHOWERS AND THUNDERSTORMS. AN OCCASIONAL GUST TO 15 KT POSSIBLE THROUGH EARLY EVENING. KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE THIS EVENING FOR DEVELOPING SHOWERS AND THUNDERSTORMS. KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE THIS EVENING FOR DEVELOPING SHOWERS AND THUNDERSTORMS. CIGS COULD VARY BETWEEN MVFR AND VFR INTO THIS EVENING. .OUTLOOK FOR 18Z FRI THROUGH TUESDAY... .FRI-TUE...SUB VFR POSSIBLE AT TIMES WITH PERIODS OF SHOWERS AND TSTMS. && .MARINE... A STRENGTHENING SOUTHERLY FLOW IS EXPECTED TO DEVELOP MARGINAL SCA SEAS OVER THE OCEAN WATERS TONIGHT. MARGINAL SCA GUSTS ARE POSSIBLE AS A LOW LEVEL JET MOVES OVER THE AREA TONIGHT...AND PASSES EAST FRIDAY MORNING. S/SW FLOW CONTINUES THROUGH FRIDAY NIGHT...BUT WINDS ARE EXPECTED TO BE BELOW SCA LEVELS. SCA SOUTHERLY SWELLS SHOULD CONTINUE THROUGH. HAVE CONTINUED TO UNDERCUT WNA GUIDANCE BY 1-2 FT BASED ON GUIDANCE TREND AND ITS PERFORMANCE THIS SUMMER. POTENTIAL EXISTS FOR AN EXTENDED PERIOD OF HAZARDOUS OCEAN SEAS VIA PERSISTENT LONG FETCH SOUTHERLY FLOW. WINDS ARE EXPECTED TO STAY BELOW CRITERIA. UNDERCUT WAVEWATCH BY A ABOUT A FOOT ON THE OCEAN WATERS FOR MUCH OF THE PERIOD. && .HYDROLOGY... PATTERN INTO TONIGHT CONTINUES TO LOOK CONDUCIVE TO BANDS OF HEAVY RAIN SHOWERS AND THUNDERSTORMS TRAINING OVER THE SAME AREA...WHICH WOULD CAUSE URBAN AND SMALL STREAM FLASH FLOODING. ON AVERAGE 1/2 TO 1 1/2 INCHES OF RAINFALL EXPECTED ACROSS LI AND CT...WITH 1 1/2 TO 2 1/2 INCHES OF RAINFALL ACROSS NE NJ AND THE LOWER HUDSON VALLEY. THE HIGHER AMOUNTS IN BOTH AREAS WILL BE TO THE N AND W. LOCALLY HIGHER AMOUNTS ARE LIKELY IN THE PATH OF TRAINING ACTIVITY. RAINFALL RATES OF 2 TO 3 INCHES PER HOUR HAVE BEEN OBSERVED WITH THE STRONGER THUNDERSTORMS THIS AFTERNOON. NEEDLESS TO SAY IF THIS TYPE OF ACTIVITY TRAINS OVER AN AREA FOR AN HOUR...URBAN AND SMALL STREAM FLASH FLOODING WILL OCCUR. THE MAIN THREAT FOR URBAN FLASH FLOODING LOOKS TO BE THROUGH 06Z ACROSS THE WESTERN 1/2 OF THE CWA...AND THROUGH AROUND DAYBREAK ACROSS LI/CT. SMALL STREAMS COULD CONTINUE RISING INTO FRIDAY MORNING. MEANWHILE...MAIN STEM RIVERS WILL SEE RISES...BUT THEY ARE EXPECTED TO REMAIN WELL WITHIN THEIR BANKS. WITH SOME UNCERTAINTY ON THE EVOLUTION OF CONVECTION ON FRIDAY...WILL CONTINUE FLASH FLOOD WATCH UNTIL 6 PM FRIDAY AND LET SUBSEQUENT SHIFTS TAKE DOWN IF NEEDED. ADDITIONAL BOUTS OF HEAVY SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS WEEKEND INTO EARLY NEXT WEEK...POSING ADDITIONAL THREATS FOR FLOODING. FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CTZ005>012. NY...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NYZ067>075- 078>081-176>179. NJ...FLASH FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR NJZ002-004-006- 103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...NV NEAR TERM...JMC/NV SHORT TERM...NV LONG TERM...DW AVIATION...JC/DS MARINE...NV/DW HYDROLOGY...NV/DW
AREA FORECAST DISCUSSION
NWS ALBANY NY
135 PM EDT WED JUN 26 2013 .SYNOPSIS... MAINLY CLOUDY CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON AND INTO THE EVENING WITH SHOWERS AND THUNDERSTORMS. SOME OF THE THUNDERSTORMS COULD PRODUCE HEAVY RAINFALL. A LOW PRESSURE SYSTEM WILL BRING A WIDESPREAD HEAVY RAINFALL AND SOME THUNDERSTORMS TO THE REGION LATE THURSDAY THROUGH FRIDAY. UNSETTLED WEATHER WILL CONTINUE INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 135 PM EDT...VISIBLE SATELLITE IMAGERY SHOWS WIDESPREAD CLOUDS ACROSS THE CWA EARLY THIS AFTERNOON. LOOKING AT KENX RADAR...THERE CURRENTLY IS ONE BATCH OF MODERATE RAIN SHOWERS ACROSS THE LAKE GEORGE AREA...WITH LOCALLY OVER AN INCH OF RAIN ALREADY HAVING FALLEN FROM THIS ACTIVITY. MEANWHILE...THE REMAINDER OF THE REGION IS FAIRLY QUIET...WITH JUST SOME SCT LIGHT RAIN SHOWERS. A WEAK SHORTWAVE WILL BE PASSING ACROSS THE REGION THIS AFTERNOON INTO THIS EVENING...WHICH MAY ENHANCE THE CURRENT SHOWER/TSTM ACTIVITY. THE 15Z HRRR SHOWS A BROKEN LINE OF SHOWERS AND THUNDERSTORMS MOVING SOUTHEAST ACROSS CENTRAL AND SOUTHERN PARTS OF THE CWA FOR THE LATE AFTN INTO THE EVENING HOURS. WITH THE CLOUD COVER IN PLACE...INSTABILITY WILL BE LIMITED THIS AFTERNOON. HOWEVER...PWATS REMAIN HIGH...WITH A READING AROUND 1.75 INCHES FOR ALBANY BASED ON THE 12Z KALY SOUNDING AND 12Z BUFKIT MODEL SOUNDINGS FOR KALB. LATEST SFC OBS SHOW DEWPOINTS IN THE UPPER 60S TO LOW 70S...SO ANY THUNDERSTORM WILL BE CAPABLE OF HVY RAINFALL. THE SEVERE THREAT MAY BE LIMITED DUE TO CLOUD COVER/LIMITED INSTABILITY...BUT SPC MAINTAINS A SLIGHT RISK OVER MUCH OF THE REGION. THE MAIN THREAT TODAY IS PROBABLY HEAVY RAINFALL AND POTENTIAL LOCALIZED FLOODING...ALTHOUGH A ROGUE SEVERE WIND GUST OR MARGINAL SEVERE HAIL CANNOT TOTALLY BE RULED OUT...ESP IF SOME BREAKS IN THE CLOUDS WERE TO OCCUR. WITH THE CLOUDS IN PLACE...MAX TEMPS WILL BE HELD DOWN...ESP COMPARED TO RECENT DAYS. MAX TEMPS IN THE UPPER 70S TO MID 80S ARE EXPECTED...WITH THE WARMEST READINGS ACROSS THE SOUTHEASTERN PART OF THE CWA. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... TONIGHT...THE SHOWERS AND THUNDERSTORMS SHOULD DIMINISH OVER THE SRN PORTION QUICKLY EARLY THIS EVENING WITH A WEAK MICRO RIDGE BUILDING IN OVER NY AND PA. THE SFC HIGH WILL NUDGE IN FROM SE ONTARIO...AND THE ERN GREAT LAKES REGION. A PARTIAL CLEARING OVER THE NRN PORTION OF THE FCST AREA WILL ALLOW PATCHY FOG TO FORM AGAIN WITH LIGHT WINDS AND MOISTURE IN THE BOUNDARY LAYER. LOW TEMPS IN THE LOWER TO MID 60S WILL BE COMMON...WITH PERHAPS SOME U60S IN THE VALLEYS. WEAK WARM ADVECTION COMMENCES OVER THE SRN TIER AHEAD OF A WARM FRONT/THERMAL TROUGH...AS A LOW PRESSURE SYSTEM WITH STRONG SHORT-WAVE TROUGH APPROACHES FROM THE OHIO VALLEY AND THE LOWER GREAT LAKES REGION TOWARDS 12Z/THU. THE SHOWALTER VALUES LOWER TO -1C NEAR THE MID HUDSON VALLEY...SO A SLIGHT OR LOW CHC OF SHOWERS AND THUNDERSTORMS WAS INCLUDED TOWARDS DAYBREAK. THU-THU NIGHT...ANOTHER ACTIVE STRETCH OF WX AS THE POTENT SHORT- WAVE TROUGH SWINGS TOWARD THE REGION WITH A SFC CYCLONE LIFTING NORTHWARD FROM PA INTO W-CNTRL NY IN THE AFTERNOON. THE ISENTROPIC LIFT INCREASES AHEAD OF THE WARM FRONT FOR SHOWERS AND SCT THUNDERSTORMS TO INCREASE FROM SOUTH TO NORTH DURING THE AFTERNOON. THE PLACEMENT OF THE WARM SECTOR IS NEBULOUS STILL...AND PERHAPS THE SRN MOST ZONES MAY GET INTO ONE BEFORE SUNSET. THE AMOUNTS OF INSTABILITY LOOKS VARIABLE ON THE GUIDANCE AND THE LOW-LEVEL JET DOES NOT CRANK UP UNTIL NIGHTFALL /30-40 KTS AT H850/. THE GFS DOES SHOW A BRIEF PERIOD OF MLCAPES OF 500-1500 J/KG IN THE AFTERNOON OVER THE SRN MOST ZONES. AGREE WITH SPC THAT 5% WIND PROBABILITIES LOOK GOOD AT THIS POINT FOR A FEW STRONG TO MAYBE SEVERE THUNDERSTORMS. THE QG LIFT STRENGTHENS ON THE NORTH SIDE OF THE SFC WAVE AND AHEAD OF THE WARM FRONT. USED THE WEATHER PHRASING AS RAIN HEAVY AT TIMES WITH A CHC OF THUNDERSTORMS WITH SHOWALTER VALUES OF 0 TO -2C...ESPECIALLY AT NIGHT. PWATS WILL BE RUNNING A FEW STANDARD DEVIATIONS ABOVE NORMAL FOR SOME VERY HEAVY RAINFALL POSSIBLE. A FLASH FLOOD OR FLOOD WATCH MAY BE NEEDED LATER IN TIME. THE WPC QPF WAS ACCEPTED WITH 1-2+ INCHES OF RAINFALL POSSIBLE THU-THU NIGHT OVER THE FCST AREA. THE HEAVIEST RAINFALL LOOKS LIKE IT WILL BE OVER THE SRN DACKS REGION AND MOHAWK VALLEY. WPC ALSO HAS A SLIGHT RISK OF FLASH FLOODING FOR THE FCST AREA. THE ECMWF AND GFS QPF LOOK CLOSER TO WPC THAN THE NAM. THE HEAVIEST RAIN AXIS APPEARS IT WILL BE OVER W-CNTRL NY. NO POINTS ARE FORECASTED TO FLOOD ON THE MAIN STEM RIVERS AT THIS TIME. CATEGORICAL AND LIKELY POPS WERE USED IN THE PM AND NIGHT TIME PERIOD. MAX TEMPS IN THE 70S TO L80S WILL BE COMMON WITH LOWS IN THE 60S. FRIDAY...FOLLOWED THE GFS/ECMWF WHERE A DRY SLOT TO THE SYSTEM MAY SHUT THE RAINFALL OFF IN THE LATE MORNING...ESPECIALLY OVER THE SRN TWO THIRDS OF THE FCST AREA. SMALL AMOUNTS OF INSTABILITY...AND POSSIBILITY OF A LITTLE SUN STILL WARRANTED A CHANCE OF THUNDERSTORMS. THE SFC WAVE WILL BE OVER SRN QUEBEC WITH A FRONTAL BOUNDARY STALLING NEAR THE REGION. ANOTHER IMPULSE ROUNDING THE BASE OF THE TROUGH COULD REKINDLE THE SHOWERS IN THE AFTERNOON. THE GFSMOS MAX TEMPS WERE FAVORED AGAIN. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... THE WEATHER PATTERN WILL BE A VERY HUMID AND UNSETTLED DURING THE LONG TERM PERIOD. THE MEDIUM RANGE MODELS INDICATE THAT A DEEP TROF WILL SET UP ACROSS THE MIDDLE OF THE COUNTRY WHILE A LARGE UPPER LEVEL RIDGE WILL BUILD OVER THE WESTERN ATLANTIC OFF THE MID ATLANTIC COAST. THIS WILL KEEP THE REGION IN A SOUTHWEST FLOW OF VERY MOIST AIR THROUGH THE PERIOD WITH A STALLED FRONTAL BOUNDARY SOMEWHERE ALONG THE EAST COAST. THIS SHOULD RESULT IN AT LEAST SCATTERED SHOWERS AND TSTMS EACH DAY...WITH THE GREATEST COVERAGE OCCURRING DURING THE AFTN AND EVENING. ALTHOUGH SOME SHORT WAVE TROFS MAY EVENTUALLY RIDE ALONG THIS SOUTHWEST FLOW OF MOIST AIR AND PROVIDE ADDITIONAL FOCUS TO THE CONVECTION/PCPN...MODELS ARE NOT INDICATING ANY OBVIOUS SYSTEMS AT THIS TIME...SO PREFERRED TO KEEP POPS IN THE CHANCE RANGE (40 TO 50 PERCENT) DURING THE ENTIRE LONG TERM PERIOD AND LATER FORECAST CAN REFINE PERIOD WHERE POPS MAY NEED TO BE HIGHER. ALTHOUGH THIS TYPE OF PATTERN FREQUENTLY RESULTS IN VERY WARM OR HOT TEMPS...FAIRLY WIDESPREAD CLOUD COVER AND OCNL PCPN WILL KEEP HIGH TEMPS IN THE MID 70S TO LOWER 80S SATURDAY THRU TUESDAY. HOWEVER... DEWPOINTS IN THE 60S WILL MAKE IT FEEL UNCOMFORTABLE. LOW TEMPS WILL BE WARM WITH LOWS IN THE UPPER 50S AND 60S FRIDAY NIGHT THROUGH MONDAY NIGHT. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... A WEAK SURFACE/UPPER LEVEL TROF WILL MOVE ACROSS THE TAF SITES INTO THIS EVENING. AN AREA OF SHOWERS HAS BEEN AFFECTING KGFL WITH MVFR CONDITIONS...AND AN MVFR CEILING IS AFFECTING KPSF. AN AREA OF SHOWERS SHOULD EXIT THE KGFL AREA BETWEEN 19Z-21Z...WHILE LIGHTER SHOWERS DEVELOP AND TRACK TOWARD KALB AND KPSF. THE SCATTERED NATURE TO THE SHOWERS SUGGESTS PUTTING VCSH AT THOSE SITES THIS AFTERNOON. SOME SCATTERED THUNDERSTORM ACTIVITY COULD DEVELOP TOWARD KPOU BUT AGAIN SCATTERED NATURE SUGGESTS VCSH UNTIL ACTUAL THUNDERSTORM DEVELOPMENT WHEN AMENDMENTS MAY BE NEEDED. ALL SHOWER AND THUNDERSTORM ACTIVITY SHOULD END THIS EVENING AND SOME CLEARING SHOULD TAKE PLACE...WITH JUST SCATTERED CLOUDS THIS EVENING. FOG IS LIKELY TO DEVELOP AFTER MIDNIGHT AND CONTINUE THROUGH ABOUT 14Z...WITH SOME LOW CEILINGS POTENTIALLY DEVELOPING ALONG WITH THE FOG. ANY FOG AND LOW CLOUDS SHOULD LIFT BY 14Z...AND VFR CONDITIONS SHOULD PREVAIL AT ALL THE SITES THROUGH THE REST OF TOMORROW MORNING. WINDS SHOULD BE LIGHT SOUTH TO SOUTHWEST THIS AFTERNOON...AND NEARLY CALM TONIGHT. WINDS SHOULD BE VARIABLE TO LIGHT SOUTH AT 6 KT OR LESS TOMORROW MORNING. OUTLOOK... THU-FRI...VFR/MVFR. SHOWERS LIKELY W/CHC -TSRAS. SAT-MON ...VFR/MVFR IN CHC -SHRAS/-TSRAS. && .FIRE WEATHER... ANOTHER DISTURBANCE TODAY WILL FOCUS ANOTHER ROUND OF ISOLATED TO SCATTERED THUNDERSTORMS WITH WARM AND HUMID CONDITIONS PREVAILING. SOME OF THE THUNDERSTORMS COULD BE STRONG TO SEVERE WITH VERY HEAVY RAINFALL. A LOW PRESSURE SYSTEM WILL BRING A WIDESPREAD POTENTIALLY HEAVY RAINFALL AND SOME STRONG THUNDERSTORMS TO THE REGION THURSDAY THROUGH FRIDAY. HIGH RH VALUES AND WET CONDITIONS WILL PERSIST FOR THE NEXT SEVERAL DAYS...AND THEIR WILL BE NO FIRE WEATHER ISSUES. && .HYDROLOGY... THE UNSETTLED WEATHER CONTINUES...AS THE WEEK PROGRESSES WITH A POTENTIAL POTENT STORM IMPACTING THE REGION LATE THURSDAY INTO FRIDAY. FIRST...THE SHOWERS AND THUNDERSTORMS WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL TODAY. SOME TRAINING OF THE CELLS WILL HAVE TO BE MONITORED THIS AFTERNOON INTO TONIGHT. PONDING OF WATER ON ROADWAYS ALONG WITH MINOR FLOODING OF LOW LYING AND POOR DRAINAGE AREAS IS EXPECTED WITH THE HEAVY RAINFALL. ALSO SOME SMALL STREAMS...CREEKS...AND BROOKS MAY REACH BANKFULL OR EVEN FLOODING QUICKLY ESPECIALLY IF STORMS MOVE OVER THE SAME AREA REPEATEDLY. THE RAINFALL FROM THE LOW PRESSURE SYSTEM AND ITS WARM FRONT THURSDAY INTO FRIDAY MORNING COULD PRODUCE 1 TO 2 INCHES OF RAINFALL WITH LOCALLY HIGHER AMOUNTS. THE WPC QPF WAS USED IN THIS TIME FRAME. A FLASH FLOOD WATCH OR FLOOD WATCH MAY BE NEEDED IF THE POTENTIAL FOR WIDESPREAD FLOODING LOOKS LIKELY. MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED FRIDAY THROUGH THE WEEKEND WHICH WILL ALLOW SOILS TO BECOME MORE SATURATED AND INCREASES THE POTENTIAL RISK OF 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. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS/NAS/WASULA NEAR TERM...FRUGIS SHORT TERM...WASULA LONG TERM...SNYDER AVIATION...NAS FIRE WEATHER...WASULA HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1014 AM EDT WED JUN 26 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF THE EAST COAST AND ACROSS THE ATLANTIC OCEAN INTO NEXT WEEK. A LEE SIDE TROUGH WILL REMAIN ACROSS THE AREA TODAY INTO TONIGHT. AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND INTO THE NORTHEAST THURSDAY INTO THURSDAY NIGHT, BRINGING A SLOW MOVING COLD FRONT INTO THE AREA THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... CHALLENGING DAY AHEAD... THE 12Z IAD SOUNDING IS HOT...96F FULL SUN. CONVECTIVELY IT LOOKS A LITTLE DRY AND AT 93/66...DOESN`T FIRE STORMS. FURTHER NORTH WHERE NO ACTUAL SOUNDING...WE PRESUME MORE UNSTABLE... ESPECIALLY BENEATH A MODELED SHORT WAVE TRANSLATING EWD ALONG AND N OF 40N THRU PA/NJ THIS AFTN. WILL ADJUST TEMPS SLIGHTLY THE NEXT SEVERAL HOURS UNDER HEAVIER MID MORNING CLOUD COVER NE PA AND NNJ. HEAT ADVISORY: MAY DISCONTINUE AT 1115 AM. SFC DEWPOINTS ARE ABOUT 3-4F LESS THAN 24 HOURS AGO AND SO WITH A MAX TEMP PROJECTED AROUND 93F...MAX HI 96. NOT QUITE OUR CRITERIA OF 98 IN LATE JUNE. CONVECTIVELY... THE 13Z RAP HAS SCT TSTMS BREAKING OUT IN THE NW 1/3 RD OF OUR AREA AROUND 21Z VIA THE MORE RELIABLE STABLE PCPN OUTPUT. RAP CONVECT BEGINS 1-2 HOURS SOONER. 1355Z COSPA GIVE PHL TIL AT LEAST 19Z BEFORE CONVECTION DEVELOPS ON ITS DOORSTEP. COSPA STILL DEVELOPS A LARGE AREA OF BANDED HEAVY CONVECTION IN SE PA BETWEEN 20-22Z. 12Z NAM LOOKS LIT UP A LITTLE EARLY AT 18Z AND SO THAT AFFECTS ITS SFC TEMP FCST WHICH IS STILL 90 AT 18Z AT KPHL. MLCAPE HAS ABOUT 2000 J THIS AFTN. BULK SHEAR LOOKS WEAK BUT AS PER YDY... ISOLATED SVR ARE POSSIBLE IN THE MID-UPPER 90S HEAT INDEX REGION WITH PLENTY OF CAPE. TONIGHT...CONVECTION DIMINISHES SEWD THRU S NJ AND DELMARVA AROUND 02-04Z AND ANOTHER FAIR HUMID HAZY NIGHT IS IN STORE. && .SHORT TERM /THURSDAY/... HEAVY CONVECTION EXPECTED IN THE AFTN OR EARLY AT NIGHT WITH AN APPROACHING TROUGH AND LOWERING SFC PRES. KI IS MORE WIDESPREAD THAN THAT OF TODAY. MAX TEMPS AROUND 2F LOWER THAN THOSE OF TODAY AND SO STILL A SMALL CHANCE OF 90F FOR S NJ AND THE PHL AREA SOUTHWESTWARD... DEPENDENT ON CLOUD COVER AND PCPN PRIOR TO 18Z. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... BY THURSDAY, THE LEE SIDE TROUGH WILL GET SQUEEZED OUT AS AN AREA OF LOW PRESSURE MOVES OUT OF THE OHIO RIVER VALLEY AND INTO THE NORTHEAST THURSDAY INTO THURSDAY NIGHT, WHILE BRINGING A COLD FRONT ACROSS. THIS LOW PRESSURE WILL DRIFT NORTHWARD THROUGH THE NORTHEAST AND INTO CANADA FRIDAY INTO THE WEEKEND. THE AFOREMENTIONED FRONT WILL LIKELY STALL ALONG THE EAST COAST INTO THE WEEKEND. A LONG WAVE TROUGH LOOKS TO DEVELOP FROM EASTERN CANADA, THROUGH THE GREAT LAKES AND INTO BUILD DOWN INTO THE CENTRAL GULF STATES DURING THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP A SOUTHWEST FLOW ACROSS THE AREA FOR A PROLONGED PERIOD. WITH THE FRONTAL BOUNDARY NEAR THE AREA AND PERIODIC SHORT WAVES/VORT MAX IMPULSES EMBEDDED IN THE CYCLONIC FLOW, THIS WILL BE A FAIRLY UNSETTLED WEATHER PATTERN. EACH PERIOD WILL HAVE CHANCE/LIKELY POP, AND WITH THE WARM, UNSTABLE AIRMASS, THUNDERSTORMS WILL BE POSSIBLE EACH DAY AS WELL. PW VALUES WILL REMAIN HIGH, AROUND 1.5-2 INCHES, SO HEAVY RAIN WILL BE A CONCERN. TEMPERATURES WILL REMAIN FAIRLY WARM AND ARE EXPECTED TO BE A FEW DEGREES ABOVE NORMAL EACH DAY, ALTHOUGH NOT AS WARM AS THE BEGINNING OF THIS WEEK. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...VFR SCT-BKN CLOUDS AOA 5000 FT. SW WIND G 15 KT. BANDS OF TSTMS DEVELOP AFTER 18Z IN E PA WITH MOSTLY W-NW GUSTS 30-40 KT AND BRIEF IFR CONDITIONS IN TSTMS. TONIGHT...LEFTOVER CONVECTION DIES AND SO VFR SCT-BKN AOA 5000 FT. POSSIBLE MVFR FOG HAZE LATE. LIGHT S-SW WIND. CONFIDENCE IN PRECIP/ CLOUDS TONIGHT IS LESS THAN AVERAGE. THURSDAY...AFTER ANY EARLY MVFR HAZE...VFR SCT-BKN CLOUDS AOA 5000 FT WITH BANDS OF IFR TSTMS IN THE AFTN/EVENING GENERATING W WIND GUSTS 30-40 KT. OUTLOOK... THURSDAY THROUGH SUNDAY...GENERALLY VFR WITH PERIODS OF MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND MORNING LOW CLOUDS/FOG. && .MARINE... THE PRESSURE GRADIENT OVER THE WATERS TODAY WILL FAVOR A SW FLOW WITH SPEEDS AROUND 10 TO 15 KNOTS. SEAS SHOULD REMAIN IN THE 3 TO 4 FT RANGE OUT OVER THE OCEAN WATERS AND 1 TO 2 FEET ON DEL BAY. WHILE SCA CONDITION ARE NOT EXPECTED TODAY AND TONIGHT...TSTMS WITH GUSTY WINDS ARE POSSIBLE THIS AFTERNOON AND TONIGHT. BE PREPARED FOR HIGHER WINDS AND SEAS IN ANY TSTM. SMW`S MAY BE ISSUED LATER TODAY. THURSDAY...THE SLY FLOW STRENGTHENS AHEAD OF THE APPROACHING TROUGH AND DEEPENING SFC LOW INTO N PA AND S NYS. SCA SOUTHERLY FLOW SEAS MAY REACH CRITERIA ON THE ATLC WATERS BUT THERE IS QUESTION WHETHER THE WAA IS OVERFORECASTING THE SLY SWELL. OUTLOOK... SMALL CRAFT ADVISORY CONDITIONS MAY RETURN TO THE ATLANTIC COASTAL WATERS INTO THE WEEKEND. SOUTHWEST WINDS ARE EXPECTED TO INCREASE AHEAD OF AN APPROACHING COLD FRONT THAT WILL STALL ALONG THE EAST COAST THROUGH THE WEEKEND. WINDS MAY PERIODICALLY GUSTA ROUND 25 KNOTS THROUGH THE PERIOD. ALSO, SEAS ARE FORECAST TO BUILD TO 5-6 FEET WITH THE SOUTHWESTERLY FLOW AS WELL. && .RIP CURRENTS... LOW RISK TODAY BUT NOT A NO RISK!! MARGINALLY LOW TOMORROW IN NJ IF THE SLY SWELL BUILDS TO 4 FT WITH A 7 SEC PERIOD AND THE S WIND AVERAGES 14 KT MIDDAY. && .CLIMATE... TEMPS BELOW... PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF 1 TO 2 DEGREES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE NORMAL AT KACY. PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL. THE JUNE 1981-2010 AVG IS 73.2. JUNE RAINFALL BELOW.. KILG ALREADY RECORD MONTHLY RFALL AT 10.09 KPHL RANKED #2 AT 8.80 INCHES BEHIND THE 10.06 JUNE 1998 RECORD. KACY RANKED #3 AT 7.20 BEHIND THE 7.57 IN 1935 AND RECORD JUNE TOTAL OF 8.45 IN 1920. KABE STILL RANKED 8TH WETTEST JUNE AT 6.48 INCHES. THE MONTHLY RECORD IS 10.51 IN 1938. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ070-071-102- 104-106. NJ...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NJZ015-017>019. DE...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR DEZ001. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG/O`HARA 1015 SHORT TERM...DRAG/O`HARA 1015 LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON/O`HARA 1015 MARINE...DRAG/ROBERTSON/O`HARA 1015 RIP CURRENTS... CLIMATE...1015
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
914 AM EDT WED JUN 26 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF THE EAST COAST AND ACROSS THE ATLANTIC OCEAN INTO NEXT WEEK. A LEE SIDE TROUGH WILL REMAIN ACROSS THE AREA TODAY INTO TONIGHT. AN AREA OF LOW PRESSURE WILL MOVE OUT OF THE OHIO RIVER VALLEY AND INTO THE NORTHEAST THURSDAY INTO THURSDAY NIGHT, BRINGING A SLOW MOVING COLD FRONT INTO THE AREA THAT WILL LIKELY STALL OUT ALONG THE EAST COAST INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... CHALLENGING DAY AHEAD... THE 12Z IAD SOUNDING IS HOT...96F FULL SUN. CONVECTIVELY IT LOOKS A LITTLE DRY AND AT 93/66...DOESN`T FIRE STORMS. FURTHER NORTH WHERE NO ACTUAL SOUNDING...WE PRESUME MORE UNSTABLE...ESPECIALLY BENEATH A MODELED SHORT WAVE TRANSLATING EWD ALONG AND N OF 40N THRU PA/NJ THIS AFTN. SO...THE HEAT ADVISORY CONTINUES AS THE POORLY MODELED W PA CONVECTION CONTINUES TO FRITTER PERMITTING PLENTY OF SUN. KEEPING AN EYE ON THE 1218Z CONVECTION NEAR KEKN BUT FOR NOW THINKING IT TENDS TO WANE. CONVECTIVELY... THE 10Z RAP HAS THE PCPN BREAKING OUT SUDDENLY IN THE NW 1/3 RD OF OUR AREA AROUND 21Z VIA THE MORE RELIABLE STABLE PCPN OUTPUT. RAP CONVECT BEGINS 1-2 HOURS SOONER. THE COSPA GIVE PHL TIL 19Z BEFORE CONVECTION DEVELOPS ON ITS DOORSTEP. COSPA DEVELOPS A LARGE AREA OF BANDED HEAVY CONVECTION IN SE PA BETWEEN 19-21Z. MLCAPE HAS ABOUT 2000 J THIS AFTN. BULK SHEAR LOOKS WEAK BUT AS PER YDY... ISOLATED SVR ARE POSSIBLE IN THE MID-UPPER 90S HEAT INDEX REGION WITH PLENTY OF CAPE. TONIGHT...CONVECTION DIMINISHES AND ANOTHER FAIR HUMID HAZY NIGHT IS IN STORE. && .SHORT TERM /THURSDAY/... HEAVY CONVECTION EXPECTED IN THE AFTN OR EARLY AT NIGHT WITH AN APPROACHING TROUGH. KI IS MORE WIDESPREAD THAN THAT OF TODAY. MAX TEMPS AROUND 2F LOWER THAN THOSE OF TODAY AND SO STILL A SMALL CHANCE OF 90F FOR S NJ AND THE PHL AREA SOUTHWESTWARD... DEPENDENT ON CLOUD COVER AND PCPN PRIOR TO 18Z. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... BY THURSDAY, THE LEE SIDE TROUGH WILL GET SQUEEZED OUT AS AN AREA OF LOW PRESSURE MOVES OUT OF THE OHIO RIVER VALLEY AND INTO THE NORTHEAST THURSDAY INTO THURSDAY NIGHT, WHILE BRINGING A COLD FRONT ACROSS. THIS LOW PRESSURE WILL DRIFT NORTHWARD THROUGH THE NORTHEAST AND INTO CANADA FRIDAY INTO THE WEEKEND. THE AFOREMENTIONED FRONT WILL LIKELY STALL ALONG THE EAST COAST INTO THE WEEKEND. A LONG WAVE TROUGH LOOKS TO DEVELOP FROM EASTERN CANADA, THROUGH THE GREAT LAKES AND INTO BUILD DOWN INTO THE CENTRAL GULF STATES DURING THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL KEEP A SOUTHWEST FLOW ACROSS THE AREA FOR A PROLONGED PERIOD. WITH THE FRONTAL BOUNDARY NEAR THE AREA AND PERIODIC SHORT WAVES/VORT MAX IMPULSES EMBEDDED IN THE CYCLONIC FLOW, THIS WILL BE A FAIRLY UNSETTLED WEATHER PATTERN. EACH PERIOD WILL HAVE CHANCE/LIKELY POP, AND WITH THE WARM, UNSTABLE AIRMASS, THUNDERSTORMS WILL BE POSSIBLE EACH DAY AS WELL. PW VALUES WILL REMAIN HIGH, AROUND 1.5-2 INCHES, SO HEAVY RAIN WILL BE A CONCERN. TEMPERATURES WILL REMAIN FAIRLY WARM AND ARE EXPECTED TO BE A FEW DEGREES ABOVE NORMAL EACH DAY, ALTHOUGH NOT AS WARM AS THE BEGINNING OF THIS WEEK. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...VFR SCT-BKN CLOUDS AOA 5000 FT. SW WIND G 15 KT. BANDS OF TSTMS DEVELOP AFTER 18Z IN E PA WITH MOSTLY W-NW GUSTS 30-40 KT AND BRIEF IFR CONDITIONS IN TSTMS. TONIGHT...LEFTOVER CONVECTION DIES AND SO VFR SCT-BKN AOA 5000 FT. POSSIBLE MVFR FOG HAZE LATE. LIGHT S-SW WIND. CONFIDENCE IN PRECIP/CLOUDS TONIGHT IS LESS THAN AVERAGE. THURSDAY...AFTER ANY EARLY MVFR HAZE...VFR SCT-BKN CLOUDS AOA 5000 FT WITH BANDS OF IFR TSTMS IN THE AFTN/EVENING GENERATING W WIND GUSTS 30-40 KT. OUTLOOK... THURSDAY THROUGH SUNDAY...GENERALLY VFR WITH PERIODS OF MVFR/IFR POSSIBLE EACH DAY WITH SHOWERS AND THUNDERSTORMS AND MORNING LOW CLOUDS/FOG. && .MARINE... THE PRESSURE GRADIENT OVER THE WATERS TODAY WILL FAVOR A SW FLOW WITH SPEEDS AROUND 10 TO 15 KNOTS. SEAS SHOULD REMAIN IN THE 3 TO 4 FT RANGE OUT OVER THE OCEAN WATERS AND 1 TO 2 FEET ON DEL BAY. WHILE SCA CONDITION ARE NOT EXPECTED TODAY AND TONIGHT...TSTMS WITH GUSTY WINDS ARE POSSIBLE THIS AFTERNOON AND TONIGHT. BE PREPARED FOR HIGHER WINDS AND SEAS IN ANY TSTM. SMW`S MAY BE ISSUED LATER TODAY. THURSDAY...THE SLY FLOW TIGHTENS A BIT AHEAD OF THE APPROACHING TROUGH AND THAT MAY BE ENOUGH TO DEVELOP SCA SOUTHERLY SWELL SEAS BUT THERE IS QUESTION WHETHER THE WAA IS OVER FORECASTING THE SLY SWELL. OUTLOOK... SMALL CRAFT ADVISORY CONDITIONS MAY RETURN TO THE ATLANTIC COASTAL WATERS INTO THE WEEKEND. SOUTHWEST WINDS ARE EXPECTED TO INCREASE AHEAD OF AN APPROACHING COLD FRONT THAT WILL STALL ALONG THE EAST COAST THROUGH THE WEEKEND. WINDS MAY PERIODICALLY GUSTA ROUND 25 KNOTS THROUGH THE PERIOD. ALSO, SEAS ARE FORECAST TO BUILD TO 5-6 FEET WITH THE SOUTHWESTERLY FLOW AS WELL. && .RIP CURRENTS... LOW TODAY. MARGINALLY LOW TOMORROW IN NJ IF THE SLY SWELL BUILDS TO 4 FT WITH 7 SEC AND THE S WIND AVERAGES 14 KT MIDDAY. && .CLIMATE... PROJECTING AN ABOVE NORMAL MONTH FOR ALL STATIONS ON THE ORDER OF 1 TO 2 DEGS REES EXCEPT A LITTLE LESS THAN A DEGREE ABOVE NORMAL AT KACY. PHL SPECIFICALLY PROJECTS 74.5 OR 1.3 ABOVE NORMAL. THE JUNE AVG IS 73.2. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ070-071-102- 104-106. NJ...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NJZ015-017>019. DE...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR DEZ001. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG/O`HARA 913 SHORT TERM...DRAG/O`HARA 913 LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON/O`HARA 913 MARINE...DRAG/ROBERTSON/O`HARA 913 RIP CURRENTS...913 CLIMATE...913
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
842 PM EDT Thu Jun 27 2013 .NEAR TERM [Rest of Tonight]... Current satellite and radar analysis shows an MCS developing over Central Georgia and Alabama. This MCS will propagate southward overnight and increase our rain chances for our GA and AL counties. Models disagree on the persistence of this MCS through the overnight, with our local WRF and EastARW WRF showing a persistent MCS that moves off the FL Panhandle in the pre-dawn hours, and the HRRR showing a system that collapses a few hours after sunset. The 00Z sounding shows ample CAPE above 3500 J/kg, PWAT values at 1.89 in, and weak vertical wind shear. While we do anticipate this system to weaken and propagate more to the SW as current trends are showing, we do think the MCS will hold together in some capacity, increasing rain chances for SW Georgia, SE Alabama, and possibly the FL Panhandle. This MCS will be capable of producing strong to severe storms with straight line winds being the primary concern. && .SHORT TERM [Friday Through Saturday Night]... The mean upper trough axis is forecast to remain east of the forecast area through Friday. This will lead to one more day of northerly mid-level flow and the potential for convection to push southward into the area late the afternoon or early in the evening. The timing and location of this convection will be tricky, as lingering early morning convection over the Florida zones could influence development later in the day. High-res guidance reflects this uncertainty, showing a variety of evolutions for convection on Friday. With this uncertainty in mind, have gone conservatively with high chance PoPs for most locations Friday and Friday evening. With the expected late start to convection once again, expect high temperatures to reach the mid 90s for many locations. By Saturday, the wetter pattern that has been advertised for several days will begin to develop as the upper trough deepens and retrogrades to the west. This will shift the deep layer flow to the southwest with significantly deeper moisture in place. In addition, a shortwave moving into the base of the trough will help to enhance convective development as well. Will go with likely PoPs for most of the area for Saturday, with highs only topping out in the upper 80s to near 90. && .LONG TERM [Sunday through Thursday]... Unseasonably deep upper trough is forecast to continue slowly retrograding through the middle of next week, keeping most of the forecast area under the influence of a moist and unsettled southwesterly deep layer flow. At the surface, a relatively stationary frontal boundary will remain in place, roughly bisecting the forecast area from northeast to southwest early in the period, before sliding back to the west by the middle of the week. Areas to the east of this boundary will have the greatest potential for heavy rain, with lighter amounts expected west of the boundary. Exactly where this boundary is on a day-to-day basis remain uncertain, so have kept the PoP gradient somewhat broad, with the highest PoPs (60s-70s) in the east and lower PoPs (30-40s) in the west. && .AVIATION...[Through 00Z Saturday] There is still significant model discrepancy on the timing of the line of thunderstorms currently moving through Central GA. Have weighted forecast with our local WRF to reflect flight restrictions later in the TAF period. The highest confidence in thunderstorms occurring at all terminals is between 03-07Z, bringing MVFR flight restrictions. During the afternoon there is higher confidence in thunderstorms at TLH and VLD, otherwise went with a VCTS for ABY, ECP, and DHN. Outside of thunderstorms VFR conditions will prevail. && .MARINE... Southwesterly flow over the waters is forecast to gradually increase into the weekend as a frontal boundary approaches from the north, and the Bermuda high strengthens over the western Atlantic. This may lead to cautionary conditions by Saturday afternoon, with brief Advisory level conditions Saturday night into Sunday morning. Thereafter, moderate southwesterly winds are forecast to continue into early next week. && .FIRE WEATHER... Average to above average summertime moisture levels will keep Red Flag conditions out of the forecast for the foreseeable future. Above average rain chances are expected through the weekend. && .HYDROLOGY... As upper level troughing digs into the SErn U.S., we will enter a wet pattern. Expect a rainy weekend with around 2-2.5" of rainfall across the forecast area with locally higher amounts where showers are heaviest. While this is over a more widespread area than we`ve been seeing lately, it is over the course of a 3 day period, and there are currently no area rivers that are in flood or action stage. No area rivers are anticipated to reach flood stage at this time. Some storms with locally higher rainfall amounts may cause flooding of urban and/or low-lying areas. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 74 94 75 89 72 / 60 50 40 70 50 Panama City 78 91 79 87 77 / 70 50 40 60 50 Dothan 75 95 75 90 73 / 60 50 50 70 50 Albany 75 95 75 91 72 / 70 50 50 70 50 Valdosta 73 93 75 89 72 / 50 50 40 70 50 Cross City 73 91 74 89 73 / 40 40 30 60 40 Apalachicola 77 90 79 87 77 / 60 50 40 60 50 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...WALSH/WOOL SHORT TERM/LONG TERM/MARINE...CAMP AVIATION...NAVARRO/HARRIGAN HYDROLOGY...MOORE
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1110 AM EDT Wed Jun 26 2013 .NEAR TERM [Rest of Today]... No significant changes were made to the inherited forecast which seems to be generally on track. Isolated to scattered afternoon thunderstorms are expected today, with somewhat lower coverage than what we saw yesterday. The best coverage of thunderstorms should be in the eastern portions of our forecast area - from south-central Georgia into the Florida Big Bend. The PoP gradient was sharpened a bit - nudged to ~50% in the Suwannee River vicinity and lowered to ~20% in parts of southeast Alabama. High temperatures remain mostly unchanged in the mid-90s away from the coasts. We can`t rule out a stronger storm or two, as is typical this time of year along the Gulf coast (our climatological probability is ~2% chance of damaging winds within 25 miles of a point for today). However, a slight drying in the boundary layer over the past 24 hours should yield a less robust CAPE profile today which points to lower chances of isolated severe storms than we saw yesterday. && .SHORT TERM [Thursday through Friday]... Upper level trofing will continue dipping further south over the Ern CONUS through the period. This will continue to veer the flow from SWrly flow to Wrly. The flow Thursday will be moderate (<10 kts), which would mean a regime 4 sea breeze day. Generally these days have lots of showers and thunderstorms in north Florida near the coast, but drier air from the west will enter the region and should keep coverage a little lower. In fact, because of a cold front to our north on Thursday, our northern counties have a slightly better chance for rain on Thursday afternoon than our Florida counties do. Friday, the flow will be stronger (>10 kts), meaning a regime 5 sea breeze day. These days typically see an earlier start and are active inland, not just along the coast. As the cold front dips further south Friday, expanded morning type 5 PoPs north and have a blend of model confidence and sea breeze for the afternoon, giving a broad area of chances for showers and thunderstorms Friday. Highs Thursday will be in the mid 90s and lows Thursday night will be in the mid 70s. && .LONG TERM [Friday Night through Tuesday]... A highly amplified upper level pattern with a deep trough becoming firmly established over the eastern CONUS through the period. A series of impulses are forecast to round the base of the trough enhancing convection over the Tri-state area. A fairly potent shortwave is forecast by the GFS to arrive on Saturday. The Bermuda ridge will build westward early next week with the axis of the trough retrograding to the Mississippi Valley. This will place the local region under deep and very moist southwest flow. From all appearances this will be an active period for convection with at least climo PoPs (40-50%) each afternoon. Temps will be near seasonal levels. && .AVIATION... [Through 12Z Thursday] A somewhat tricky TAF package for the overnight hours, as the usually very reliable NARRE and HRRR are generally devoid of any significant restrictions. Some of the numerical guidance did show some MVFR level cigs or vis, so did fcst periods of MVFR conditions at ECP and DHN, which were the 2 sites that had the most measurable rainfall yesterday. As for the daylight hours, it appears to be fairly convectively quiet for a Type 4 sea breeze day with the upper level ridge dominating, but did go with 30 and 40 percent PoPs as mentioned above. Left ECP free from convection at this time, went with prob30 groups at TLH and DHN, and finally convective tempos at ABY and VLD. && .MARINE... Winds and waves over coastal waters will begin to pick up a bit this weekend as a front approaches from our north. Winds will shift to westerly at around 10-15 kts with waves building to 2-3 feet Friday into Saturday. By Sunday, winds will be around 15 kts and waves may reach about 4 feet, but should begin decreasing again by Monday. Exercise caution conditions are possible on Sunday. && .FIRE WEATHER... Relative humidity values will stay safely above Red Flag criteria through the period. && .HYDROLOGY... With no river sites currently in flood stage or action stage, and with QPF for the next 3 days from WPC of <1", no flooding on area rivers is expected in the next few days. Later this weekend and early into next week, there is some potential for higher rainfall amounts as a frontal system dips southward into our area, but they should still be too low to cause widespread flooding. WPC is showing QPF of 1-1.5" for Saturday through Sunday and 1-1.75" Monday through Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 96 73 94 74 93 / 40 30 30 20 50 Panama City 90 77 91 78 89 / 30 20 30 20 40 Dothan 94 74 95 75 94 / 30 20 30 30 50 Albany 95 74 95 74 93 / 30 20 40 30 40 Valdosta 94 71 94 74 93 / 50 30 30 30 50 Cross City 93 73 93 73 91 / 40 30 30 20 40 Apalachicola 89 75 89 77 88 / 30 20 20 20 40 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Lamers SHORT TERM...Moore LONG TERM...Barry AVIATION...Gould MARINE...Moore FIRE WEATHER...Gould HYDROLOGY...Moore
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
301 AM EDT Wed Jun 26 2013 .NEAR TERM [Today]... Upper level ridging will continue to dominate the SE US for at least a couple of more days, giving us hot and humid conditions with high temps in the middle 90s across the interior, until a shortwave trof becomes reestablished by late in the week and the upcoming weekend. With the drier deep layer air, cut back on PoPs just a bit from Tuesday`s forecast, but still believe the Type 4 Sea Breeze pattern (light to moderate SW Flow between 1000 and 700 mb) will be respectable enough to produce PoPs in the 30 to 40 percent range, highest across the NE half of the CWA. As for storm intensity, generally poor mid and upper level lapse rates combined with continued warming aloft should preclude any significant strong to severe storms, but the fairly light steering flow at the lower levels could result in some locally heavy rainfall in the stronger storms. && .SHORT TERM [Thursday through Friday]... Upper level trofing will continue dipping further south over the Ern CONUS through the period. This will continue to veer the flow from SWrly flow to Wrly. The flow Thursday will be moderate (<10 kts), which would mean a regime 4 sea breeze day. Generally these days have lots of showers and thunderstorms in north Florida near the coast, but drier air from the west will enter the region and should keep coverage a little lower. In fact, because of a cold front to our north on Thursday, our northern counties have a slightly better chance for rain on Thursday afternoon than our Florida counties do. Friday, the flow will be stronger (>10 kts), meaning a regime 5 sea breeze day. These days typically see an earlier start and are active inland, not just along the coast. As the cold front dips further south Friday, expanded morning type 5 PoPs north and have a blend of model confidence and sea breeze for the afternoon, giving a broad area of chances for showers and thunderstorms Friday. Highs Thursday will be in the mid 90s and lows Thursday night will be in the mid 70s. && .LONG TERM [Friday Night through Tuesday]... A highly amplified upper level pattern with a deep trough becoming firmly established over the eastern CONUS through the period. A series of impulses are forecast to round the base of the trough enhancing convection over the Tri-state area. A fairly potent shortwave is forecast by the GFS to arrive on Saturday. The Bermuda ridge will build westward early next week with the axis of the trough retrograding to the Mississippi Valley. This will place the local region under deep and very moist southwest flow. From all appearances this will be an active period for convection with at least climo PoPs (40-50%) each afternoon. Temps will be near seasonal levels. && .AVIATION... [Through 12Z Thursday] A somewhat tricky TAF package for the overnight hours, as the usually very reliable NARRE and HRRR are generally devoid of any significant restrictions. Some of the numerical guidance did show some MVFR level cigs or vis, so did fcst periods of MVFR conditions at ECP and DHN, which were the 2 sites that had the most measurable rainfall yesterday. As for the daylight hours, it appears to be fairly convectively quiet for a Type 4 sea breeze day with the upper level ridge dominating, but did go with 30 and 40 percent PoPs as mentioned above. Left ECP free from convection at this time, went with prob30 groups at TLH and DHN, and finally convective tempos at ABY and VLD. && .MARINE... Winds and waves over coastal waters will begin to pick up a bit this weekend as a front approaches from our north. Winds will shift to westerly at around 10-15 kts with waves building to 2-3 feet Friday into Saturday. By Sunday, winds will be around 15 kts and waves may reach about 4 feet, but should begin decreasing again by Monday. Exercise caution conditions are possible on Sunday. && .FIRE WEATHER... Relative humidity values will stay safely above Red Flag criteria through the period. && .HYDROLOGY... With no river sites currently in flood stage or action stage, and with QPF for the next 3 days from WPC of <1", no flooding on area rivers is expected in the next few days. Later this weekend and early into next week, there is some potential for higher rainfall amounts as a frontal system dips southward into our area, but they should still be too low to cause widespread flooding. WPC is showing QPF of 1-1.5" for Saturday through Sunday and 1-1.75" Monday through Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 95 73 94 74 93 / 30 30 30 20 50 Panama City 91 77 91 78 89 / 30 20 30 20 40 Dothan 95 74 95 75 94 / 30 20 30 30 50 Albany 96 74 95 74 93 / 40 20 40 30 40 Valdosta 96 71 94 74 93 / 40 30 30 30 50 Cross City 94 73 93 73 91 / 30 30 30 20 40 Apalachicola 90 75 89 77 88 / 30 20 20 20 40 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Weather...Gould Short Term/Marine/Hydrology...Moore Long Term...Barry
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
253 PM CDT WED JUN 26 2013 .DISCUSSION... 308 AM CDT THE LATEST IN A SERIES OF WEAK SHORTWAVES IN QUASI-ZONAL SOUTHERN STREAM FLOW HAS BEEN SUPPORTING WIDESPREAD CONVECTION AS IT MOVES TOWARD THE AREA EARLY THIS MORNING. GRADUALLY OVER THE NEXT TWO DAYS THE LARGE SCALE PATTERN WILL BE AMPLIFYING INTO A BROAD ANTICYCLONE ACROSS THE WESTERN CONUS AND A DEEPENING LONGWAVE TROUGH OVER THE EASTERN STATES. THE WARM HUMID CONDITIONS OF RECENT DAYS WILL BE REPLACED BY COOL HUMID CONDITIONS BY THE WEEKEND...WHICH THEN WILL PERSIST INTO NEXT WEEK. FIRST QUESTION CONCERNS PRECIPITATION TRENDS FOR TODAY. AT 08Z THE EXISTING AREAS OF CONVECTION ACROSS NORTHEAST IOWA INTO NORTHERN ILLINOIS WERE LOCATED ALONG FAVORABLE GRADIENTS OF MOISTURE TRANSPORT ON THE LEADING EDGE OF THE LOW LEVEL JET...AND UNDER A WEAK SHORTWAVE DEPICTED IN THE RAP MODEL AND VWP OBS AT 850 AND 700 MB. THIS ACTIVITY SHOULD BE MOVING ACROSS NORTHEASTERN ILLINOIS DURING THE PREDAWN HOURS BUT THEN BEGINNING TO WEAKEN AS THE LLJ VEERS AND ADJUSTS ITS FOCUS MORE TOWARD CENTRAL AND SOUTHERN ILLINOIS. IF THIS ACTIVITY DOES DISSIPATE AS EXPECTED TOWARD MORNING...THE PROSPECTS OF REDEVELOPMENT TODAY ARE SOMEWHAT UNCERTAIN DESPITE MODEL QPF SOLUTIONS TO THE CONTRARY. LINGERING MORNING SHOWERS AND THEN SCATTERED TSRA LATER ARE DEFINITELY NOT OUT OF THE QUESTION LOCALLY BUT THE MORE FAVORABLE AREAS OF MOISTURE ADVECTION AND STEEP MID LEVEL LAPSE RATES ARE FARTHER SOUTH TOWARD CENTRAL ILLINOIS AND FARTHER NORTH ALONG THE WI/MN STATE LINE. DESPITE THE APPROACH OF A SURFACE/850 FRONTAL ZONE...THE UPPER LEVEL WAVES APPEAR TO BE SOMEWHAT OUT OF SYNC AND MORE PROGRESSIVE...LEAVING THE LOWER LEVEL FEATURES UNDER AREAS OF RISING HEIGHTS ALOFT. IN THE 0530Z SPC DAY 1 OUTLOOK THE SLIGHT RISK EXTENDS NORTHWEST TOWARD MSP AND THEN WELL SOUTH AND EAST THROUGH THE TENNESSEE AND OHIO VALLEYS. WOULD NOT BE SURPRISED TO SEE THIS SPLIT IN LATER UPDATES...WITH THE THUMB TO OUR NORTHWEST SEPARATED FROM THE AREA TO OUR SOUTH. BUT THAT WOULD BE CUTTING IT PRETTY FINE GIVEN THE OVERALL UNCERTAINTY WITH THIS SITUATION. LONG STORY SHORT...FOR TODAY THE PLAN WILL BE TO LOWER POPS INTO THE CHANCE CATEGORY BY AFTERNOON FOR MOST OF THE AREA BUT KEEP IN MIND THE PWATS APPROACHING TWO INCHES AND THEREFORE MAINTAIN THE FLASH FLOOD WATCH AND THE MENTION OF TSRA. AFTER TODAY THE SITUATION BECOMES ONLY SLIGHTLY MORE CLEAR BUT OF SEEMINGLY LESSER IMPACT. AMPLIFICATION OF THE LARGE SCALE FLOW WILL BEGIN TO INFLUENCE THE LOCAL AREA BY TONIGHT INTO THURSDAY AFTER THE SURFACE TROUGH PUSHES THROUGH THE AREA AND WINDS AT ALL LEVELS TURN TO THE NORTHWEST. LOW LEVEL WARMTH AND HUMIDITY DO NOT REALLY DEPART UNTIL FRIDAY WHEN THE EXPANDING EASTERN TROUGH PUSHES THE UPPER JET SOUTH OF THE AREA AND USHERS IN SLIGHTLY DRIER BUT MILDER AIR. WITH ONLY MARGINAL LAPSE RATES AND HEIGHTS ALOFT CONTINUING TO INCREASE...NEITHER THURSDAY NOR FRIDAY LOOK PARTICULARLY FAVORABLE FOR WIDESPREAD PRECIPITATION. AS MENTIONED IN AN EARLIER DISCUSSION...IT WOULD NOT TAKE MUCH OF A SHORTWAVE IN THE UPPER FLOW TO SUPPORT AN AFTERNOON SHOWER...SO WILL CONTINUE TO CARRY SLIGHT CHANCE POPS ON BOTH DAYS. BY THE WEEKEND THE CONVECTIVE INSTABILITY APPEARS TO HAVE DECREASED...BUT THE PRESENCE OF BOTH A SURFACE AND UPPER LEVEL TROUGH DROPPING SOUTH ACROSS THE AREA WILL STILL SUPPORT LARGE SCALE LIFT...PRIMARILY TO THE SOUTH ON SUNDAY. PRECIP CHANCES FINALLY DECREASE BY EARLY NEXT WEEK AS THE SURFACE AND UPPER SUPPORT DIMINISH...BUT UNSEASONABLY COOL AIR REMAINS IN PLACE WITH CONTINUED NORTH TO NORTHEASTERLY WINDS. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * UNCERTAINTIES REMAIN WITH PRECISE WIND DIRECTION THIS AFTERNOON * MVFR VSBY IN BR POSSIBLE LATE TONIGHT/VERY EARLY THURS AM * CHANCE OF TSRA AGAIN THURS PM IZZI //DISCUSSION...UPDATED 20Z... WIND DIRECTIONS CONTINUE TO BE A CHALLENGE THIS AFTERNOON WITH SMALL MESOLOW THAT WAS OVER NW IL PERSISTING SURPRISINGING LONG AND NOW PUSHING INTO NE IL. WINDS HAVE BEEN VEERING AROUND TO A MORE WESTERLY DIRECTION AND WITH LATEST AMENDMENTS HAVE ADJUSTED THE FORECAST ACCORDINGLY. DON`T SEE A GOOD REASON FOR WINDS TO BACK TO MORE SOUTHERLY AND IF ANYTHING GO MORE WESTERLY THIS AFTERNOON BEFORE DIMINSHING THIS EVENING. IZZI UPDATED 18Z... OVERNIGHT AND MORNING THUNDERSTORMS HAVE FINALLY DIMINISHED LEAVING A LARGE POOL OF STABLE AIR OVER THE REGION WHICH SHOULD RESULT IN MINIMAL THREAT ADDITIONAL CONVECTION DEVELOPING THIS AFTERNOON OR TONIGHT. WINDS HAVE RAPIDLY SWUNG AROUND TO THE S/SSW AND WITH FURTHER HEATING/MIXING WOULD EXPECT THE SOUTHERLY WINDS TO CONTINUE THROUGH THE AFTERNOON WITH ONLY A MINIMAL THREAT OF WINDS BACKING TO EASTERLY DIRECTION AFTER TODAY. WINDS SHOULD GO LIGHT/VARIABLE TONIGHT AND COULD ACTUALLY SEE SOME PATCY GROUND FOG DEVELOP LATE TONIGHT...PARTICULARLY IN THE OUTLYING AREAS. AN UPPER LEVEL DISTURBANCE IS PROGGED TO SWING THROUGH THE REGION DURING THE AFTERNOON RESULTING IN SCT`D TSRA DEVELOPING...SOME POSSIBLY STRONG TO SEVERE. IZZI //ORD AND MDW CONFIDENCE...UPDATED 20Z... * LOW-MEDIUM CONFIDENCE IN WIND DIRECTION REMAINDER OF THIS AFTERNOON * MEDIUM-HIGH CONFIDENCE IN DRY WEATHER THROUGH THURS MORNING * LOW-MEDIUM CONFIDENCE IN TSRA CHANCES THURS AFTERNOON * HIGH CONFIDENCE IN OTHER ELEMENTS IZZI //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY THROUGH SATURDAY...PERIODIC CHANCES OF TSRA. SATURDAY THROUGH MONDAY...PERIODIC CHANCES OF SHRA. TUESDAY...CHC TSRA. BMD && .MARINE... 150 AM CDT ELONGATED SFC LOW PRESSURE TROUGH OVER THE MID-UPPER MISSOURI VALLEY WILL MOVE SLOWLY EAST TODAY...WITH VARYING MODEL FORECASTS DEVELOPING A WEAK SURFACE LOW PRESSURE WAVE IN THE VICINITY OF NORTHERN IL/IND OR SOUTHERN LAKE MICHIGAN BY THIS EVENING. SOUTH TO SOUTHEAST WINDS SHOULD DIMINISH IN SPEED AS THE GRADIENT WEAKENS WITH THE APPROACH OF THE TROUGH THIS AFTERNOON...WITH LAKE BREEZE ESPECIALLY ALONG THE WESTERN SHORE. THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE...WHICH MAY RESULT IN SOME LOCALLY STRONGER WINDS. WINDS MAY BECOME SOMEWHAT VARIABLE AT 10 KT OR LESS TONIGHT AS THE SURFACE TROUGH/COLD FRONT MOVE SLOWLY ACROSS THE LAKE...EVENTUALLY TAKING ON A WEST- NORTHWEST DIRECTION THURSDAY AS THE TROUGH MOVES OFF TO THE EAST. SPEEDS SHOULD REMAIN GENERALLY LIGHT HOWEVER...WITH A RELATIVELY WEAK GRADIENT INTO FRIDAY. WEAK HIGH PRESSURE RIDGING WILL DEVELOP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS INTO THE WEEKEND...WHILE THE LOW PRESSURE WAVE EVENTUALLY DEEPENS EAST OF THE LAKES. THIS WILL MAINTAIN A PROLONGED PERIOD OF NORTH-NORTHWEST FLOW ACROSS LAKE MICHIGAN...THOUGH AGAIN WITH SPEEDS GENERALLY 15 KT OR LESS THROUGH THE PERIOD. OTHERWISE...IN THE NEAR TERM SOME PATCHY DENSE FOG WILL LINGER ACROSS THE NORTHERN PART OF THE LAKE THIS MORNING. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ023-ILZ033-ILZ039 UNTIL 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1239 PM CDT WED JUN 26 2013 .DISCUSSION... 308 AM CDT THE LATEST IN A SERIES OF WEAK SHORTWAVES IN QUASI-ZONAL SOUTHERN STREAM FLOW HAS BEEN SUPPORTING WIDESPREAD CONVECTION AS IT MOVES TOWARD THE AREA EARLY THIS MORNING. GRADUALLY OVER THE NEXT TWO DAYS THE LARGE SCALE PATTERN WILL BE AMPLIFYING INTO A BROAD ANTICYCLONE ACROSS THE WESTERN CONUS AND A DEEPENING LONGWAVE TROUGH OVER THE EASTERN STATES. THE WARM HUMID CONDITIONS OF RECENT DAYS WILL BE REPLACED BY COOL HUMID CONDITIONS BY THE WEEKEND...WHICH THEN WILL PERSIST INTO NEXT WEEK. FIRST QUESTION CONCERNS PRECIPITATION TRENDS FOR TODAY. AT 08Z THE EXISTING AREAS OF CONVECTION ACROSS NORTHEAST IOWA INTO NORTHERN ILLINOIS WERE LOCATED ALONG FAVORABLE GRADIENTS OF MOISTURE TRANSPORT ON THE LEADING EDGE OF THE LOW LEVEL JET...AND UNDER A WEAK SHORTWAVE DEPICTED IN THE RAP MODEL AND VWP OBS AT 850 AND 700 MB. THIS ACTIVITY SHOULD BE MOVING ACROSS NORTHEASTERN ILLINOIS DURING THE PREDAWN HOURS BUT THEN BEGINNING TO WEAKEN AS THE LLJ VEERS AND ADJUSTS ITS FOCUS MORE TOWARD CENTRAL AND SOUTHERN ILLINOIS. IF THIS ACTIVITY DOES DISSIPATE AS EXPECTED TOWARD MORNING...THE PROSPECTS OF REDEVELOPMENT TODAY ARE SOMEWHAT UNCERTAIN DESPITE MODEL QPF SOLUTIONS TO THE CONTRARY. LINGERING MORNING SHOWERS AND THEN SCATTERED TSRA LATER ARE DEFINITELY NOT OUT OF THE QUESTION LOCALLY BUT THE MORE FAVORABLE AREAS OF MOISTURE ADVECTION AND STEEP MID LEVEL LAPSE RATES ARE FARTHER SOUTH TOWARD CENTRAL ILLINOIS AND FARTHER NORTH ALONG THE WI/MN STATE LINE. DESPITE THE APPROACH OF A SURFACE/850 FRONTAL ZONE...THE UPPER LEVEL WAVES APPEAR TO BE SOMEWHAT OUT OF SYNC AND MORE PROGRESSIVE...LEAVING THE LOWER LEVEL FEATURES UNDER AREAS OF RISING HEIGHTS ALOFT. IN THE 0530Z SPC DAY 1 OUTLOOK THE SLIGHT RISK EXTENDS NORTHWEST TOWARD MSP AND THEN WELL SOUTH AND EAST THROUGH THE TENNESSEE AND OHIO VALLEYS. WOULD NOT BE SURPRISED TO SEE THIS SPLIT IN LATER UPDATES...WITH THE THUMB TO OUR NORTHWEST SEPARATED FROM THE AREA TO OUR SOUTH. BUT THAT WOULD BE CUTTING IT PRETTY FINE GIVEN THE OVERALL UNCERTAINTY WITH THIS SITUATION. LONG STORY SHORT...FOR TODAY THE PLAN WILL BE TO LOWER POPS INTO THE CHANCE CATEGORY BY AFTERNOON FOR MOST OF THE AREA BUT KEEP IN MIND THE PWATS APPROACHING TWO INCHES AND THEREFORE MAINTAIN THE FLASH FLOOD WATCH AND THE MENTION OF TSRA. AFTER TODAY THE SITUATION BECOMES ONLY SLIGHTLY MORE CLEAR BUT OF SEEMINGLY LESSER IMPACT. AMPLIFICATION OF THE LARGE SCALE FLOW WILL BEGIN TO INFLUENCE THE LOCAL AREA BY TONIGHT INTO THURSDAY AFTER THE SURFACE TROUGH PUSHES THROUGH THE AREA AND WINDS AT ALL LEVELS TURN TO THE NORTHWEST. LOW LEVEL WARMTH AND HUMIDITY DO NOT REALLY DEPART UNTIL FRIDAY WHEN THE EXPANDING EASTERN TROUGH PUSHES THE UPPER JET SOUTH OF THE AREA AND USHERS IN SLIGHTLY DRIER BUT MILDER AIR. WITH ONLY MARGINAL LAPSE RATES AND HEIGHTS ALOFT CONTINUING TO INCREASE...NEITHER THURSDAY NOR FRIDAY LOOK PARTICULARLY FAVORABLE FOR WIDESPREAD PRECIPITATION. AS MENTIONED IN AN EARLIER DISCUSSION...IT WOULD NOT TAKE MUCH OF A SHORTWAVE IN THE UPPER FLOW TO SUPPORT AN AFTERNOON SHOWER...SO WILL CONTINUE TO CARRY SLIGHT CHANCE POPS ON BOTH DAYS. BY THE WEEKEND THE CONVECTIVE INSTABILITY APPEARS TO HAVE DECREASED...BUT THE PRESENCE OF BOTH A SURFACE AND UPPER LEVEL TROUGH DROPPING SOUTH ACROSS THE AREA WILL STILL SUPPORT LARGE SCALE LIFT...PRIMARILY TO THE SOUTH ON SUNDAY. PRECIP CHANCES FINALLY DECREASE BY EARLY NEXT WEEK AS THE SURFACE AND UPPER SUPPORT DIMINISH...BUT UNSEASONABLY COOL AIR REMAINS IN PLACE WITH CONTINUED NORTH TO NORTHEASTERLY WINDS. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SOME UNCERTAINTIES REMAIN WITH WIND DIRECTION THIS AFTERNOON * MVFR VSBY IN BR POSSIBLE LATE TONIGHT/VERY EARLY THURS AM * CHANCE OF TSRA AGAIN THURS PM IZZI //DISCUSSION...UPDATED 18Z... OVERNIGHT AND MORNING THUNDERSTORMS HAVE FINALLY DIMINISHED LEAVING A LARGE POOL OF STABLE AIR OVER THE REGION WHICH SHOULD RESULT IN MINIMAL THREAT ADDITIONAL CONVECTION DEVELOPING THIS AFTERNOON OR TONIGHT. WINDS HAVE RAPIDLY SWUNG AROUND TO THE S/SSW AND WITH FURTHER HEATING/MIXING WOULD EXPECT THE SOUTHERLY WINDS TO CONTINUE THROUGH THE AFTERNOON WITH ONLY A MINIMAL THREAT OF WINDS BACKING TO EASTERLY DIRECTION AFTER TODAY. WINDS SHOULD GO LIGHT/VARIABLE TONIGHT AND COULD ACTUALLY SEE SOME PATCY GROUND FOG DEVELOP LATE TONIGHT...PARTICULARLY IN THE OUTLYING AREAS. AN UPPER LEVEL DISTURBANCE IS PROGGED TO SWING THROUGH THE REGION DURING THE AFTERNOON RESULTING IN SCT`D TSRA DEVELOPING...SOME POSSIBLY STRONG TO SEVERE. IZZI //ORD AND MDW CONFIDENCE...UPDATED 18Z... * LOW-MEDIUM CONFIDENCE IN WIND DIRECTION THIS AFTERNOON * MEDIUM-HIGH CONFIDENCE IN DRY WEATHER THROUGH THURS MORNING * LOW-MEDIUM CONFIDENCE IN TSRA CHANCES THURS AFTERNOON * HIGH CONFIDENCE IN OTHER ELEMENTS IZZI //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY THROUGH SATURDAY...PERIODIC CHANCES OF TSRA. SATURDAY THROUGH MONDAY...PERIODIC CHANCES OF SHRA. TUESDAY...CHC TSRA. BMD && .MARINE... 150 AM CDT ELONGATED SFC LOW PRESSURE TROUGH OVER THE MID-UPPER MISSOURI VALLEY WILL MOVE SLOWLY EAST TODAY...WITH VARYING MODEL FORECASTS DEVELOPING A WEAK SURFACE LOW PRESSURE WAVE IN THE VICINITY OF NORTHERN IL/IND OR SOUTHERN LAKE MICHIGAN BY THIS EVENING. SOUTH TO SOUTHEAST WINDS SHOULD DIMINISH IN SPEED AS THE GRADIENT WEAKENS WITH THE APPROACH OF THE TROUGH THIS AFTERNOON...WITH LAKE BREEZE ESPECIALLY ALONG THE WESTERN SHORE. THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE...WHICH MAY RESULT IN SOME LOCALLY STRONGER WINDS. WINDS MAY BECOME SOMEWHAT VARIABLE AT 10 KT OR LESS TONIGHT AS THE SURFACE TROUGH/COLD FRONT MOVE SLOWLY ACROSS THE LAKE...EVENTUALLY TAKING ON A WEST- NORTHWEST DIRECTION THURSDAY AS THE TROUGH MOVES OFF TO THE EAST. SPEEDS SHOULD REMAIN GENERALLY LIGHT HOWEVER...WITH A RELATIVELY WEAK GRADIENT INTO FRIDAY. WEAK HIGH PRESSURE RIDGING WILL DEVELOP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS INTO THE WEEKEND...WHILE THE LOW PRESSURE WAVE EVENTUALLY DEEPENS EAST OF THE LAKES. THIS WILL MAINTAIN A PROLONGED PERIOD OF NORTH-NORTHWEST FLOW ACROSS LAKE MICHIGAN...THOUGH AGAIN WITH SPEEDS GENERALLY 15 KT OR LESS THROUGH THE PERIOD. OTHERWISE...IN THE NEAR TERM SOME PATCHY DENSE FOG WILL LINGER ACROSS THE NORTHERN PART OF THE LAKE THIS MORNING. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ023-ILZ033-ILZ039 UNTIL 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1124 AM CDT WED JUN 26 2013 .DISCUSSION... 308 AM CDT THE LATEST IN A SERIES OF WEAK SHORTWAVES IN QUASI-ZONAL SOUTHERN STREAM FLOW HAS BEEN SUPPORTING WIDESPREAD CONVECTION AS IT MOVES TOWARD THE AREA EARLY THIS MORNING. GRADUALLY OVER THE NEXT TWO DAYS THE LARGE SCALE PATTERN WILL BE AMPLIFYING INTO A BROAD ANTICYCLONE ACROSS THE WESTERN CONUS AND A DEEPENING LONGWAVE TROUGH OVER THE EASTERN STATES. THE WARM HUMID CONDITIONS OF RECENT DAYS WILL BE REPLACED BY COOL HUMID CONDITIONS BY THE WEEKEND...WHICH THEN WILL PERSIST INTO NEXT WEEK. FIRST QUESTION CONCERNS PRECIPITATION TRENDS FOR TODAY. AT 08Z THE EXISTING AREAS OF CONVECTION ACROSS NORTHEAST IOWA INTO NORTHERN ILLINOIS WERE LOCATED ALONG FAVORABLE GRADIENTS OF MOISTURE TRANSPORT ON THE LEADING EDGE OF THE LOW LEVEL JET...AND UNDER A WEAK SHORTWAVE DEPICTED IN THE RAP MODEL AND VWP OBS AT 850 AND 700 MB. THIS ACTIVITY SHOULD BE MOVING ACROSS NORTHEASTERN ILLINOIS DURING THE PREDAWN HOURS BUT THEN BEGINNING TO WEAKEN AS THE LLJ VEERS AND ADJUSTS ITS FOCUS MORE TOWARD CENTRAL AND SOUTHERN ILLINOIS. IF THIS ACTIVITY DOES DISSIPATE AS EXPECTED TOWARD MORNING...THE PROSPECTS OF REDEVELOPMENT TODAY ARE SOMEWHAT UNCERTAIN DESPITE MODEL QPF SOLUTIONS TO THE CONTRARY. LINGERING MORNING SHOWERS AND THEN SCATTERED TSRA LATER ARE DEFINITELY NOT OUT OF THE QUESTION LOCALLY BUT THE MORE FAVORABLE AREAS OF MOISTURE ADVECTION AND STEEP MID LEVEL LAPSE RATES ARE FARTHER SOUTH TOWARD CENTRAL ILLINOIS AND FARTHER NORTH ALONG THE WI/MN STATE LINE. DESPITE THE APPROACH OF A SURFACE/850 FRONTAL ZONE...THE UPPER LEVEL WAVES APPEAR TO BE SOMEWHAT OUT OF SYNC AND MORE PROGRESSIVE...LEAVING THE LOWER LEVEL FEATURES UNDER AREAS OF RISING HEIGHTS ALOFT. IN THE 0530Z SPC DAY 1 OUTLOOK THE SLIGHT RISK EXTENDS NORTHWEST TOWARD MSP AND THEN WELL SOUTH AND EAST THROUGH THE TENNESSEE AND OHIO VALLEYS. WOULD NOT BE SURPRISED TO SEE THIS SPLIT IN LATER UPDATES...WITH THE THUMB TO OUR NORTHWEST SEPARATED FROM THE AREA TO OUR SOUTH. BUT THAT WOULD BE CUTTING IT PRETTY FINE GIVEN THE OVERALL UNCERTAINTY WITH THIS SITUATION. LONG STORY SHORT...FOR TODAY THE PLAN WILL BE TO LOWER POPS INTO THE CHANCE CATEGORY BY AFTERNOON FOR MOST OF THE AREA BUT KEEP IN MIND THE PWATS APPROACHING TWO INCHES AND THEREFORE MAINTAIN THE FLASH FLOOD WATCH AND THE MENTION OF TSRA. AFTER TODAY THE SITUATION BECOMES ONLY SLIGHTLY MORE CLEAR BUT OF SEEMINGLY LESSER IMPACT. AMPLIFICATION OF THE LARGE SCALE FLOW WILL BEGIN TO INFLUENCE THE LOCAL AREA BY TONIGHT INTO THURSDAY AFTER THE SURFACE TROUGH PUSHES THROUGH THE AREA AND WINDS AT ALL LEVELS TURN TO THE NORTHWEST. LOW LEVEL WARMTH AND HUMIDITY DO NOT REALLY DEPART UNTIL FRIDAY WHEN THE EXPANDING EASTERN TROUGH PUSHES THE UPPER JET SOUTH OF THE AREA AND USHERS IN SLIGHTLY DRIER BUT MILDER AIR. WITH ONLY MARGINAL LAPSE RATES AND HEIGHTS ALOFT CONTINUING TO INCREASE...NEITHER THURSDAY NOR FRIDAY LOOK PARTICULARLY FAVORABLE FOR WIDESPREAD PRECIPITATION. AS MENTIONED IN AN EARLIER DISCUSSION...IT WOULD NOT TAKE MUCH OF A SHORTWAVE IN THE UPPER FLOW TO SUPPORT AN AFTERNOON SHOWER...SO WILL CONTINUE TO CARRY SLIGHT CHANCE POPS ON BOTH DAYS. BY THE WEEKEND THE CONVECTIVE INSTABILITY APPEARS TO HAVE DECREASED...BUT THE PRESENCE OF BOTH A SURFACE AND UPPER LEVEL TROUGH DROPPING SOUTH ACROSS THE AREA WILL STILL SUPPORT LARGE SCALE LIFT...PRIMARILY TO THE SOUTH ON SUNDAY. PRECIP CHANCES FINALLY DECREASE BY EARLY NEXT WEEK AS THE SURFACE AND UPPER SUPPORT DIMINISH...BUT UNSEASONABLY COOL AIR REMAINS IN PLACE WITH CONTINUED NORTH TO NORTHEASTERLY WINDS. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * SCTD SHRA IN VC OF BUT MOSTLY MISSING ORD/MDW * SOUTHEAST WINDS WILL TURN MORE SOUTHERLY THIS AFTERNOON IZZI //DISCUSSION...UPDATED 14Z... UPPER LEVEL DISTURBANCE MOVING ACROSS NORTHERN ILLINOIS WILL CONTINUE TO PRODUCE SCT`D SHOWERS AND THUNDERSTORMS THROUGH THE REMAINDER OF THE MORNING HOURS. MORE ORGANIZED LINE OF TSRA SW OF JOT WILL LIFT NE AND LIKELY IMPACT MDW BY AROUND 15Z WITH PERIOD OF +TSRA AND GUSTY WINDS POSSIBLE. AS DISTURBANCE MOVES SLOWLY EAST THE COVERAGE OF SHRA/TSRA WILL PROBABLY DECREASE THIS AFTERNOON. SMALL SFC LOW SW OF RFD LIKELY TO MAINTAIN MOSTLY EASTERLY COMPONENT TO WINDS THROUGH THE MORNING HOURS WITH LOW CONFIDENCE ON THE WIND DIRECTION HEADING INTO THE AFTERNOON. IZZI UPDATED 12Z... LINE OF THUNDERSTORMS SPANS FROM NORTH CENTRAL ILLINOIS ESE INTO NORTHERN INDIANA AND IS FOCUSED ON THE NOSE OF A LOW LEVEL JET. WHILE THE FOCUS SHOULD GENERALLY LIFT NORTH AND WEAKEN OVER THE NEXT COUPLE HOURS...THE STORMS HAVE BEEN BACK BUILDING TO THE SOUTH WHICH HAS KEPT IT OVER OR ON THE DOORSTEP ON ORD...AND MAY CONTINUE TO PERSIST OVER THE NEXT HOUR OR TWO. WINDS HAVE BECOME MORE NORTHEAST/EASTERLY UNDER THE INFLUENCE OF CONVECTION...AND CIGS HAVE DROPPED TO MVFR. AS CONVECTION WANES THIS MORNING...EXPECT SOUTHERLY WINDS TO RESUME AND FOR MVFR CIGS TO LIFT BACK TO VFR. THERE SHOULD BE A LULL IN ACTIVITY FROM MID MORNING TO EARLY THIS AFTERNOON FOR THE CHICAGO TERMINALS. ATTENTION TURNS TO AN APPROACHING MCV MOVING OVER THE MISSISSIPPI RIVER EARLY THIS MORNING. WHILE THERE IS AN EXPANSIVE AREA OF STRATIFORM PRECIP AHEAD OF THIS FEATURE...IT SHOULD DRY/ERODE SOME AS IT PROGRESSES EAST. BECAUSE OF THE CLOUD COVER AND PERHAPS LIGHT RAIN...IT APPEARS THERE WILL BE LITTLE OPPORTUNITY FOR THE ATMOSPHERE TO DESTABILIZE TODAY THOUGH THERE WILL BE SOME PERSISTENT/FESTERING EMBEDDED CONVECTION ASSOCIATED WITH THE MCV. WINDS APPEAR TO GO LIGHT AND VARIABLE TONIGHT...AND NAM GUIDANCE AS WELL AS LAV POINT TO FOG/BR AND IFR CIGS DEVELOPING OVERNIGHT. WILL NOT MENTION YET IN TAFS TO WAIT AND SEE HOW THE REST OF THE DAY EVOLVES AND IF THERE IS ANY SIGNIFICANT DRYING THIS AFTERNOON/EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM-HIGH CONFIDENCE IN SHRA OVER THE REGION THROUGH EARLY AFTERNOON * MEDIUM CONFIDENCE IN WINDS THIS AFTERNOON IZZI //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY THROUGH SATURDAY...PERIODIC CHANCES OF TSRA. SATURDAY THROUGH MONDAY...PERIODIC CHANCES OF SHRA. TUESDAY...CHC TSRA. BMD && .MARINE... 150 AM CDT ELONGATED SFC LOW PRESSURE TROUGH OVER THE MID-UPPER MISSOURI VALLEY WILL MOVE SLOWLY EAST TODAY...WITH VARYING MODEL FORECASTS DEVELOPING A WEAK SURFACE LOW PRESSURE WAVE IN THE VICINITY OF NORTHERN IL/IND OR SOUTHERN LAKE MICHIGAN BY THIS EVENING. SOUTH TO SOUTHEAST WINDS SHOULD DIMINISH IN SPEED AS THE GRADIENT WEAKENS WITH THE APPROACH OF THE TROUGH THIS AFTERNOON...WITH LAKE BREEZE ESPECIALLY ALONG THE WESTERN SHORE. THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE...WHICH MAY RESULT IN SOME LOCALLY STRONGER WINDS. WINDS MAY BECOME SOMEWHAT VARIABLE AT 10 KT OR LESS TONIGHT AS THE SURFACE TROUGH/COLD FRONT MOVE SLOWLY ACROSS THE LAKE...EVENTUALLY TAKING ON A WEST- NORTHWEST DIRECTION THURSDAY AS THE TROUGH MOVES OFF TO THE EAST. SPEEDS SHOULD REMAIN GENERALLY LIGHT HOWEVER...WITH A RELATIVELY WEAK GRADIENT INTO FRIDAY. WEAK HIGH PRESSURE RIDGING WILL DEVELOP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS INTO THE WEEKEND...WHILE THE LOW PRESSURE WAVE EVENTUALLY DEEPENS EAST OF THE LAKES. THIS WILL MAINTAIN A PROLONGED PERIOD OF NORTH-NORTHWEST FLOW ACROSS LAKE MICHIGAN...THOUGH AGAIN WITH SPEEDS GENERALLY 15 KT OR LESS THROUGH THE PERIOD. OTHERWISE...IN THE NEAR TERM SOME PATCHY DENSE FOG WILL LINGER ACROSS THE NORTHERN PART OF THE LAKE THIS MORNING. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
920 AM CDT WED JUN 26 2013 .DISCUSSION... 308 AM CDT THE LATEST IN A SERIES OF WEAK SHORTWAVES IN QUASI-ZONAL SOUTHERN STREAM FLOW HAS BEEN SUPPORTING WIDESPREAD CONVECTION AS IT MOVES TOWARD THE AREA EARLY THIS MORNING. GRADUALLY OVER THE NEXT TWO DAYS THE LARGE SCALE PATTERN WILL BE AMPLIFYING INTO A BROAD ANTICYCLONE ACROSS THE WESTERN CONUS AND A DEEPENING LONGWAVE TROUGH OVER THE EASTERN STATES. THE WARM HUMID CONDITIONS OF RECENT DAYS WILL BE REPLACED BY COOL HUMID CONDITIONS BY THE WEEKEND...WHICH THEN WILL PERSIST INTO NEXT WEEK. FIRST QUESTION CONCERNS PRECIPITATION TRENDS FOR TODAY. AT 08Z THE EXISTING AREAS OF CONVECTION ACROSS NORTHEAST IOWA INTO NORTHERN ILLINOIS WERE LOCATED ALONG FAVORABLE GRADIENTS OF MOISTURE TRANSPORT ON THE LEADING EDGE OF THE LOW LEVEL JET...AND UNDER A WEAK SHORTWAVE DEPICTED IN THE RAP MODEL AND VWP OBS AT 850 AND 700 MB. THIS ACTIVITY SHOULD BE MOVING ACROSS NORTHEASTERN ILLINOIS DURING THE PREDAWN HOURS BUT THEN BEGINNING TO WEAKEN AS THE LLJ VEERS AND ADJUSTS ITS FOCUS MORE TOWARD CENTRAL AND SOUTHERN ILLINOIS. IF THIS ACTIVITY DOES DISSIPATE AS EXPECTED TOWARD MORNING...THE PROSPECTS OF REDEVELOPMENT TODAY ARE SOMEWHAT UNCERTAIN DESPITE MODEL QPF SOLUTIONS TO THE CONTRARY. LINGERING MORNING SHOWERS AND THEN SCATTERED TSRA LATER ARE DEFINITELY NOT OUT OF THE QUESTION LOCALLY BUT THE MORE FAVORABLE AREAS OF MOISTURE ADVECTION AND STEEP MID LEVEL LAPSE RATES ARE FARTHER SOUTH TOWARD CENTRAL ILLINOIS AND FARTHER NORTH ALONG THE WI/MN STATE LINE. DESPITE THE APPROACH OF A SURFACE/850 FRONTAL ZONE...THE UPPER LEVEL WAVES APPEAR TO BE SOMEWHAT OUT OF SYNC AND MORE PROGRESSIVE...LEAVING THE LOWER LEVEL FEATURES UNDER AREAS OF RISING HEIGHTS ALOFT. IN THE 0530Z SPC DAY 1 OUTLOOK THE SLIGHT RISK EXTENDS NORTHWEST TOWARD MSP AND THEN WELL SOUTH AND EAST THROUGH THE TENNESSEE AND OHIO VALLEYS. WOULD NOT BE SURPRISED TO SEE THIS SPLIT IN LATER UPDATES...WITH THE THUMB TO OUR NORTHWEST SEPARATED FROM THE AREA TO OUR SOUTH. BUT THAT WOULD BE CUTTING IT PRETTY FINE GIVEN THE OVERALL UNCERTAINTY WITH THIS SITUATION. LONG STORY SHORT...FOR TODAY THE PLAN WILL BE TO LOWER POPS INTO THE CHANCE CATEGORY BY AFTERNOON FOR MOST OF THE AREA BUT KEEP IN MIND THE PWATS APPROACHING TWO INCHES AND THEREFORE MAINTAIN THE FLASH FLOOD WATCH AND THE MENTION OF TSRA. AFTER TODAY THE SITUATION BECOMES ONLY SLIGHTLY MORE CLEAR BUT OF SEEMINGLY LESSER IMPACT. AMPLIFICATION OF THE LARGE SCALE FLOW WILL BEGIN TO INFLUENCE THE LOCAL AREA BY TONIGHT INTO THURSDAY AFTER THE SURFACE TROUGH PUSHES THROUGH THE AREA AND WINDS AT ALL LEVELS TURN TO THE NORTHWEST. LOW LEVEL WARMTH AND HUMIDITY DO NOT REALLY DEPART UNTIL FRIDAY WHEN THE EXPANDING EASTERN TROUGH PUSHES THE UPPER JET SOUTH OF THE AREA AND USHERS IN SLIGHTLY DRIER BUT MILDER AIR. WITH ONLY MARGINAL LAPSE RATES AND HEIGHTS ALOFT CONTINUING TO INCREASE...NEITHER THURSDAY NOR FRIDAY LOOK PARTICULARLY FAVORABLE FOR WIDESPREAD PRECIPITATION. AS MENTIONED IN AN EARLIER DISCUSSION...IT WOULD NOT TAKE MUCH OF A SHORTWAVE IN THE UPPER FLOW TO SUPPORT AN AFTERNOON SHOWER...SO WILL CONTINUE TO CARRY SLIGHT CHANCE POPS ON BOTH DAYS. BY THE WEEKEND THE CONVECTIVE INSTABILITY APPEARS TO HAVE DECREASED...BUT THE PRESENCE OF BOTH A SURFACE AND UPPER LEVEL TROUGH DROPPING SOUTH ACROSS THE AREA WILL STILL SUPPORT LARGE SCALE LIFT...PRIMARILY TO THE SOUTH ON SUNDAY. PRECIP CHANCES FINALLY DECREASE BY EARLY NEXT WEEK AS THE SURFACE AND UPPER SUPPORT DIMINISH...BUT UNSEASONABLY COOL AIR REMAINS IN PLACE WITH CONTINUED NORTH TO NORTHEASTERLY WINDS. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * SCT`D SHRA & TSRA LIKELY TO PERSIST NEXT FEW HOURS * EASTERLY COMPONENT TO WINDS EXPECTED NEXT SEVERAL HOURS * WINDS COULD TRANSITION TO SOUTHERLY OR SOUTHEAST THIS AFTERNOON IZZI //DISCUSSION...UPDATED 14Z... UPPER LEVEL DISTURBANCE MOVING ACROSS NORTHERN ILLINOIS WILL CONTINUE TO PRODUCE SCT`D SHOWERS AND THUNDERSTORMS THROUGH THE REMAINDER OF THE MORNING HOURS. MORE ORGANIZED LINE OF TSRA SW OF JOT WILL LIFT NE AND LIKELY IMPACT MDW BY AROUND 15Z WITH PERIOD OF +TSRA AND GUSTY WINDS POSSIBLE. AS DISTURBANCE MOVES SLOWLY EAST THE COVERAGE OF SHRA/TSRA WILL PROBABLY DECREASE THIS AFTERNOON. SMALL SFC LOW SW OF RFD LIKELY TO MAINTAIN MOSTLY EASTERLY COMPONENT TO WINDS THROUGH THE MORNING HOURS WITH LOW CONFIDENCE ON THE WIND DIRECTION HEADING INTO THE AFTERNOON. IZZI UPDATED 12Z... LINE OF THUNDERSTORMS SPANS FROM NORTH CENTRAL ILLINOIS ESE INTO NORTHERN INDIANA AND IS FOCUSED ON THE NOSE OF A LOW LEVEL JET. WHILE THE FOCUS SHOULD GENERALLY LIFT NORTH AND WEAKEN OVER THE NEXT COUPLE HOURS...THE STORMS HAVE BEEN BACK BUILDING TO THE SOUTH WHICH HAS KEPT IT OVER OR ON THE DOORSTEP ON ORD...AND MAY CONTINUE TO PERSIST OVER THE NEXT HOUR OR TWO. WINDS HAVE BECOME MORE NORTHEAST/EASTERLY UNDER THE INFLUENCE OF CONVECTION...AND CIGS HAVE DROPPED TO MVFR. AS CONVECTION WANES THIS MORNING...EXPECT SOUTHERLY WINDS TO RESUME AND FOR MVFR CIGS TO LIFT BACK TO VFR. THERE SHOULD BE A LULL IN ACTIVITY FROM MID MORNING TO EARLY THIS AFTERNOON FOR THE CHICAGO TERMINALS. ATTENTION TURNS TO AN APPROACHING MCV MOVING OVER THE MISSISSIPPI RIVER EARLY THIS MORNING. WHILE THERE IS AN EXPANSIVE AREA OF STRATIFORM PRECIP AHEAD OF THIS FEATURE...IT SHOULD DRY/ERODE SOME AS IT PROGRESSES EAST. BECAUSE OF THE CLOUD COVER AND PERHAPS LIGHT RAIN...IT APPEARS THERE WILL BE LITTLE OPPORTUNITY FOR THE ATMOSPHERE TO DESTABILIZE TODAY THOUGH THERE WILL BE SOME PERSISTENT/FESTERING EMBEDDED CONVECTION ASSOCIATED WITH THE MCV. WINDS APPEAR TO GO LIGHT AND VARIABLE TONIGHT...AND NAM GUIDANCE AS WELL AS LAV POINT TO FOG/BR AND IFR CIGS DEVELOPING OVERNIGHT. WILL NOT MENTION YET IN TAFS TO WAIT AND SEE HOW THE REST OF THE DAY EVOLVES AND IF THERE IS ANY SIGNIFICANT DRYING THIS AFTERNOON/EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM-HIGH CONFIDENCE IN SHRA/TSRA OVER THE REGION THIS MORNING * LOW CONFIDENCE IN SHRA/TSRA CHANCES THIS AFTERNOON * MEDIUM CONFIDENCE IN WIND DIRECTION OUTSIDE OF TSRA THIS MORNING * LOW CONFIDENCE IN WINDS THIS AFTERNOON IZZI //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY THROUGH SATURDAY...PERIODIC CHANCES OF TSRA. SATURDAY THROUGH MONDAY...PERIODIC CHANCES OF SHRA. TUESDAY...CHC TSRA. BMD && .MARINE... 150 AM CDT ELONGATED SFC LOW PRESSURE TROUGH OVER THE MID-UPPER MISSOURI VALLEY WILL MOVE SLOWLY EAST TODAY...WITH VARYING MODEL FORECASTS DEVELOPING A WEAK SURFACE LOW PRESSURE WAVE IN THE VICINITY OF NORTHERN IL/IND OR SOUTHERN LAKE MICHIGAN BY THIS EVENING. SOUTH TO SOUTHEAST WINDS SHOULD DIMINISH IN SPEED AS THE GRADIENT WEAKENS WITH THE APPROACH OF THE TROUGH THIS AFTERNOON...WITH LAKE BREEZE ESPECIALLY ALONG THE WESTERN SHORE. THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE...WHICH MAY RESULT IN SOME LOCALLY STRONGER WINDS. WINDS MAY BECOME SOMEWHAT VARIABLE AT 10 KT OR LESS TONIGHT AS THE SURFACE TROUGH/COLD FRONT MOVE SLOWLY ACROSS THE LAKE...EVENTUALLY TAKING ON A WEST- NORTHWEST DIRECTION THURSDAY AS THE TROUGH MOVES OFF TO THE EAST. SPEEDS SHOULD REMAIN GENERALLY LIGHT HOWEVER...WITH A RELATIVELY WEAK GRADIENT INTO FRIDAY. WEAK HIGH PRESSURE RIDGING WILL DEVELOP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS INTO THE WEEKEND...WHILE THE LOW PRESSURE WAVE EVENTUALLY DEEPENS EAST OF THE LAKES. THIS WILL MAINTAIN A PROLONGED PERIOD OF NORTH-NORTHWEST FLOW ACROSS LAKE MICHIGAN...THOUGH AGAIN WITH SPEEDS GENERALLY 15 KT OR LESS THROUGH THE PERIOD. OTHERWISE...IN THE NEAR TERM SOME PATCHY DENSE FOG WILL LINGER ACROSS THE NORTHERN PART OF THE LAKE THIS MORNING. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
629 AM CDT WED JUN 26 2013 .DISCUSSION... 308 AM CDT THE LATEST IN A SERIES OF WEAK SHORTWAVES IN QUASI-ZONAL SOUTHERN STREAM FLOW HAS BEEN SUPPORTING WIDESPREAD CONVECTION AS IT MOVES TOWARD THE AREA EARLY THIS MORNING. GRADUALLY OVER THE NEXT TWO DAYS THE LARGE SCALE PATTERN WILL BE AMPLIFYING INTO A BROAD ANTICYCLONE ACROSS THE WESTERN CONUS AND A DEEPENING LONGWAVE TROUGH OVER THE EASTERN STATES. THE WARM HUMID CONDITIONS OF RECENT DAYS WILL BE REPLACED BY COOL HUMID CONDITIONS BY THE WEEKEND...WHICH THEN WILL PERSIST INTO NEXT WEEK. FIRST QUESTION CONCERNS PRECIPITATION TRENDS FOR TODAY. AT 08Z THE EXISTING AREAS OF CONVECTION ACROSS NORTHEAST IOWA INTO NORTHERN ILLINOIS WERE LOCATED ALONG FAVORABLE GRADIENTS OF MOISTURE TRANSPORT ON THE LEADING EDGE OF THE LOW LEVEL JET...AND UNDER A WEAK SHORTWAVE DEPICTED IN THE RAP MODEL AND VWP OBS AT 850 AND 700 MB. THIS ACTIVITY SHOULD BE MOVING ACROSS NORTHEASTERN ILLINOIS DURING THE PREDAWN HOURS BUT THEN BEGINNING TO WEAKEN AS THE LLJ VEERS AND ADJUSTS ITS FOCUS MORE TOWARD CENTRAL AND SOUTHERN ILLINOIS. IF THIS ACTIVITY DOES DISSIPATE AS EXPECTED TOWARD MORNING...THE PROSPECTS OF REDEVELOPMENT TODAY ARE SOMEWHAT UNCERTAIN DESPITE MODEL QPF SOLUTIONS TO THE CONTRARY. LINGERING MORNING SHOWERS AND THEN SCATTERED TSRA LATER ARE DEFINITELY NOT OUT OF THE QUESTION LOCALLY BUT THE MORE FAVORABLE AREAS OF MOISTURE ADVECTION AND STEEP MID LEVEL LAPSE RATES ARE FARTHER SOUTH TOWARD CENTRAL ILLINOIS AND FARTHER NORTH ALONG THE WI/MN STATE LINE. DESPITE THE APPROACH OF A SURFACE/850 FRONTAL ZONE...THE UPPER LEVEL WAVES APPEAR TO BE SOMEWHAT OUT OF SYNC AND MORE PROGRESSIVE...LEAVING THE LOWER LEVEL FEATURES UNDER AREAS OF RISING HEIGHTS ALOFT. IN THE 0530Z SPC DAY 1 OUTLOOK THE SLIGHT RISK EXTENDS NORTHWEST TOWARD MSP AND THEN WELL SOUTH AND EAST THROUGH THE TENNESSEE AND OHIO VALLEYS. WOULD NOT BE SURPRISED TO SEE THIS SPLIT IN LATER UPDATES...WITH THE THUMB TO OUR NORTHWEST SEPARATED FROM THE AREA TO OUR SOUTH. BUT THAT WOULD BE CUTTING IT PRETTY FINE GIVEN THE OVERALL UNCERTAINTY WITH THIS SITUATION. LONG STORY SHORT...FOR TODAY THE PLAN WILL BE TO LOWER POPS INTO THE CHANCE CATEGORY BY AFTERNOON FOR MOST OF THE AREA BUT KEEP IN MIND THE PWATS APPROACHING TWO INCHES AND THEREFORE MAINTAIN THE FLASH FLOOD WATCH AND THE MENTION OF TSRA. AFTER TODAY THE SITUATION BECOMES ONLY SLIGHTLY MORE CLEAR BUT OF SEEMINGLY LESSER IMPACT. AMPLIFICATION OF THE LARGE SCALE FLOW WILL BEGIN TO INFLUENCE THE LOCAL AREA BY TONIGHT INTO THURSDAY AFTER THE SURFACE TROUGH PUSHES THROUGH THE AREA AND WINDS AT ALL LEVELS TURN TO THE NORTHWEST. LOW LEVEL WARMTH AND HUMIDITY DO NOT REALLY DEPART UNTIL FRIDAY WHEN THE EXPANDING EASTERN TROUGH PUSHES THE UPPER JET SOUTH OF THE AREA AND USHERS IN SLIGHTLY DRIER BUT MILDER AIR. WITH ONLY MARGINAL LAPSE RATES AND HEIGHTS ALOFT CONTINUING TO INCREASE...NEITHER THURSDAY NOR FRIDAY LOOK PARTICULARLY FAVORABLE FOR WIDESPREAD PRECIPITATION. AS MENTIONED IN AN EARLIER DISCUSSION...IT WOULD NOT TAKE MUCH OF A SHORTWAVE IN THE UPPER FLOW TO SUPPORT AN AFTERNOON SHOWER...SO WILL CONTINUE TO CARRY SLIGHT CHANCE POPS ON BOTH DAYS. BY THE WEEKEND THE CONVECTIVE INSTABILITY APPEARS TO HAVE DECREASED...BUT THE PRESENCE OF BOTH A SURFACE AND UPPER LEVEL TROUGH DROPPING SOUTH ACROSS THE AREA WILL STILL SUPPORT LARGE SCALE LIFT...PRIMARILY TO THE SOUTH ON SUNDAY. PRECIP CHANCES FINALLY DECREASE BY EARLY NEXT WEEK AS THE SURFACE AND UPPER SUPPORT DIMINISH...BUT UNSEASONABLY COOL AIR REMAINS IN PLACE WITH CONTINUED NORTH TO NORTHEASTERLY WINDS. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * LINE OT THUNDERSTORMS EARLY THIS MORNING BACK BUILDING SOUTH...BUT SHOULD EVENTUALLY BEGIN TO LIFT NORTH AWAY FROM AREA AND WEAKEN. * ADDITIONAL THUNDERSTORMS POSSIBLE THIS AFTERNOON ASSOCIATED WITH THE DECAYING SYSTEM MOVING ACROSS THE MISSISSIPPI. BMD //DISCUSSION...UPDATED 12Z... LINE OF THUNDERSTORMS SPANS FROM NORTH CENTRAL ILLINOIS ESE INTO NORTHERN INDIANA AND IS FOCUSED ON THE NOSE OF A LOW LEVEL JET. WHILE THE FOCUS SHOULD GENERALLY LIFT NORTH AND WEAKEN OVER THE NEXT COUPLE HOURS...THE STORMS HAVE BEEN BACK BUILDING TO THE SOUTH WHICH HAS KEPT IT OVER OR ON THE DOORSTEP ON ORD...AND MAY CONTINUE TO PERSIST OVER THE NEXT HOUR OR TWO. WINDS HAVE BECOME MORE NORTHEAST/EASTERLY UNDER THE INFLUENCE OF CONVECTION...AND CIGS HAVE DROPPED TO MVFR. AS CONVECTION WANES THIS MORNING...EXPECT SOUTHERLY WINDS TO RESUME AND FOR MVFR CIGS TO LIFT BACK TO VFR. THERE SHOULD BE A LULL IN ACTIVITY FROM MID MORNING TO EARLY THIS AFTERNOON FOR THE CHICAGO TERMINALS. ATTENTION TURNS TO AN APPROACHING MCV MOVING OVER THE MISSISSIPPI RIVER EARLY THIS MORNING. WHILE THERE IS AN EXPANSIVE AREA OF STRATIFORM PRECIP AHEAD OF THIS FEATURE...IT SHOULD DRY/ERODE SOME AS IT PROGRESSES EAST. BECAUSE OF THE CLOUD COVER AND PERHAPS LIGHT RAIN...IT APPEARS THERE WILL BE LITTLE OPPORTUNITY FOR THE ATMOSPHERE TO DESTABILIZE TODAY THOUGH THERE WILL BE SOME PERSISTENT/FESTERING EMBEDDED CONVECTION ASSOCIATED WITH THE MCV. WINDS APPEAR TO GO LIGHT AND VARIABLE TONIGHT...AND NAM GUIDANCE AS WELL AS LAV POINT TO FOG/BR AND IFR CIGS DEVELOPING OVERNIGHT. WILL NOT MENTION YET IN TAFS TO WAIT AND SEE HOW THE REST OF THE DAY EVOLVES AND IF THERE IS ANY SIGNIFICANT DRYING THIS AFTERNOON/EVENING. BMD //ORD AND MDW CONFIDENCE...UPDATED 12Z... * MEDIUM CONFIDENCE IN A LULL IN PRECIP/TSRA MID MORNING TO EARLY AFTERNOON. * LOW CONFIDENCE IN EVOLUTION OF MCV AND RESULTING PRECIP/TSRA CHANCES THIS AFTERNOON. * LOW TO MEDIUM CONFIDENCE IN WIND TRENDS. BMD //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...VFR. FRIDAY THROUGH SATURDAY...PERIODIC CHANCES OF TSRA. SATURDAY THROUGH MONDAY...PERIODIC CHANCES OF SHRA. TUESDAY...CHC TSRA. BMD && .MARINE... 150 AM CDT ELONGATED SFC LOW PRESSURE TROUGH OVER THE MID-UPPER MISSOURI VALLEY WILL MOVE SLOWLY EAST TODAY...WITH VARYING MODEL FORECASTS DEVELOPING A WEAK SURFACE LOW PRESSURE WAVE IN THE VICINITY OF NORTHERN IL/IND OR SOUTHERN LAKE MICHIGAN BY THIS EVENING. SOUTH TO SOUTHEAST WINDS SHOULD DIMINISH IN SPEED AS THE GRADIENT WEAKENS WITH THE APPROACH OF THE TROUGH THIS AFTERNOON...WITH LAKE BREEZE ESPECIALLY ALONG THE WESTERN SHORE. THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE...WHICH MAY RESULT IN SOME LOCALLY STRONGER WINDS. WINDS MAY BECOME SOMEWHAT VARIABLE AT 10 KT OR LESS TONIGHT AS THE SURFACE TROUGH/COLD FRONT MOVE SLOWLY ACROSS THE LAKE...EVENTUALLY TAKING ON A WEST- NORTHWEST DIRECTION THURSDAY AS THE TROUGH MOVES OFF TO THE EAST. SPEEDS SHOULD REMAIN GENERALLY LIGHT HOWEVER...WITH A RELATIVELY WEAK GRADIENT INTO FRIDAY. WEAK HIGH PRESSURE RIDGING WILL DEVELOP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS INTO THE WEEKEND...WHILE THE LOW PRESSURE WAVE EVENTUALLY DEEPENS EAST OF THE LAKES. THIS WILL MAINTAIN A PROLONGED PERIOD OF NORTH-NORTHWEST FLOW ACROSS LAKE MICHIGAN...THOUGH AGAIN WITH SPEEDS GENERALLY 15 KT OR LESS THROUGH THE PERIOD. OTHERWISE...IN THE NEAR TERM SOME PATCHY DENSE FOG WILL LINGER ACROSS THE NORTHERN PART OF THE LAKE THIS MORNING. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
313 AM CDT WED JUN 26 2013 .DISCUSSION... 308 AM CDT THE LATEST IN A SERIES OF WEAK SHORTWAVES IN QUASI-ZONAL SOUTHERN STREAM FLOW HAS BEEN SUPPORTING WIDESPREAD CONVECTION AS IT MOVES TOWARD THE AREA EARLY THIS MORNING. GRADUALLY OVER THE NEXT TWO DAYS THE LARGE SCALE PATTERN WILL BE AMPLIFYING INTO A BROAD ANTICYCLONE ACROSS THE WESTERN CONUS AND A DEEPENING LONGWAVE TROUGH OVER THE EASTERN STATES. THE WARM HUMID CONDITIONS OF RECENT DAYS WILL BE REPLACED BY COOL HUMID CONDITIONS BY THE WEEKEND...WHICH THEN WILL PERSIST INTO NEXT WEEK. FIRST QUESTION CONCERNS PRECIPITATION TRENDS FOR TODAY. AT 08Z THE EXISTING AREAS OF CONVECTION ACROSS NORTHEAST IOWA INTO NORTHERN ILLINOIS WERE LOCATED ALONG FAVORABLE GRADIENTS OF MOISTURE TRANSPORT ON THE LEADING EDGE OF THE LOW LEVEL JET...AND UNDER A WEAK SHORTWAVE DEPICTED IN THE RAP MODEL AND VWP OBS AT 850 AND 700 MB. THIS ACTIVITY SHOULD BE MOVING ACROSS NORTHEASTERN ILLINOIS DURING THE PREDAWN HOURS BUT THEN BEGINNING TO WEAKEN AS THE LLJ VEERS AND ADJUSTS ITS FOCUS MORE TOWARD CENTRAL AND SOUTHERN ILLINOIS. IF THIS ACTIVITY DOES DISSIPATE AS EXPECTED TOWARD MORNING...THE PROSPECTS OF REDEVELOPMENT TODAY ARE SOMEWHAT UNCERTAIN DESPITE MODEL QPF SOLUTIONS TO THE CONTRARY. LINGERING MORNING SHOWERS AND THEN SCATTERED TSRA LATER ARE DEFINITELY NOT OUT OF THE QUESTION LOCALLY BUT THE MORE FAVORABLE AREAS OF MOISTURE ADVECTION AND STEEP MID LEVEL LAPSE RATES ARE FARTHER SOUTH TOWARD CENTRAL ILLINOIS AND FARTHER NORTH ALONG THE WI/MN STATE LINE. DESPITE THE APPROACH OF A SURFACE/850 FRONTAL ZONE...THE UPPER LEVEL WAVES APPEAR TO BE SOMEWHAT OUT OF SYNC AND MORE PROGRESSIVE...LEAVING THE LOWER LEVEL FEATURES UNDER AREAS OF RISING HEIGHTS ALOFT. IN THE 0530Z SPC DAY 1 OUTLOOK THE SLIGHT RISK EXTENDS NORTHWEST TOWARD MSP AND THEN WELL SOUTH AND EAST THROUGH THE TENNESSEE AND OHIO VALLEYS. WOULD NOT BE SURPRISED TO SEE THIS SPLIT IN LATER UPDATES...WITH THE THUMB TO OUR NORTHWEST SEPARATED FROM THE AREA TO OUR SOUTH. BUT THAT WOULD BE CUTTING IT PRETTY FINE GIVEN THE OVERALL UNCERTAINTY WITH THIS SITUATION. LONG STORY SHORT...FOR TODAY THE PLAN WILL BE TO LOWER POPS INTO THE CHANCE CATEGORY BY AFTERNOON FOR MOST OF THE AREA BUT KEEP IN MIND THE PWATS APPROACHING TWO INCHES AND THEREFORE MAINTAIN THE FLASH FLOOD WATCH AND THE MENTION OF TSRA. AFTER TODAY THE SITUATION BECOMES ONLY SLIGHTLY MORE CLEAR BUT OF SEEMINGLY LESSER IMPACT. AMPLIFICATION OF THE LARGE SCALE FLOW WILL BEGIN TO INFLUENCE THE LOCAL AREA BY TONIGHT INTO THURSDAY AFTER THE SURFACE TROUGH PUSHES THROUGH THE AREA AND WINDS AT ALL LEVELS TURN TO THE NORTHWEST. LOW LEVEL WARMTH AND HUMIDITY DO NOT REALLY DEPART UNTIL FRIDAY WHEN THE EXPANDING EASTERN TROUGH PUSHES THE UPPER JET SOUTH OF THE AREA AND USHERS IN SLIGHTLY DRIER BUT MILDER AIR. WITH ONLY MARGINAL LAPSE RATES AND HEIGHTS ALOFT CONTINUING TO INCREASE...NEITHER THURSDAY NOR FRIDAY LOOK PARTICULARLY FAVORABLE FOR WIDESPREAD PRECIPITATION. AS MENTIONED IN AN EARLIER DISCUSSION...IT WOULD NOT TAKE MUCH OF A SHORTWAVE IN THE UPPER FLOW TO SUPPORT AN AFTERNOON SHOWER...SO WILL CONTINUE TO CARRY SLIGHT CHANCE POPS ON BOTH DAYS. BY THE WEEKEND THE CONVECTIVE INSTABILITY APPEARS TO HAVE DECREASED...BUT THE PRESENCE OF BOTH A SURFACE AND UPPER LEVEL TROUGH DROPPING SOUTH ACROSS THE AREA WILL STILL SUPPORT LARGE SCALE LIFT...PRIMARILY TO THE SOUTH ON SUNDAY. PRECIP CHANCES FINALLY DECREASE BY EARLY NEXT WEEK AS THE SURFACE AND UPPER SUPPORT DIMINISH...BUT UNSEASONABLY COOL AIR REMAINS IN PLACE WITH CONTINUED NORTH TO NORTHEASTERLY WINDS. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * TSRA LATE TONIGHT/EARLY WEDNESDAY MORNING. * HEAVY RAIN AND MVFR VSBY LIKELY WITH THE TSRA. * ADDITIONAL ROUND OF TSRA PSBL WEDNESDAY AFTERNOON. * LAKE BREEZE PSBL WEDNESDAY AFTERNOON WITH WINDS BCMG E. JEE //DISCUSSION...UPDATED 06Z... HIGH PRESSURE OVER THE SE US REMAINS IN PLACE WHILE A LOW OVER THE NORTHEASTERN PLAINS SLIDES THROUGH THE WESTERN GREAT LAKES LATER TODAY. CONVECTION IS CURRENTLY ON THE RADAR IN NORTHEAST IA AND EAST CENTRAL IL/SOUTHERN IN. THE CONVECTION TO THE SOUTH SHOULD REMAIN SOUTH OF THE TERMINALS. THE STORMS OVER IA ON THE OTHER HAND SHOULD CONTINUE EASTWARD BEFORE BEGINNING TO MOVE TOWARD THE SOUTHEAST. SCATTERED CONVECTION HAS ALSO BLOSSOMED AT THE NOSE OF THE LOW LEVEL JET IN NORTHWEST IL AND SHOULD CONTINUE TO SEE MORE SCATTERED CONVECTION. LASTLY...HAVE SEEN A FEW CELLS PULSE UP AND THEN PULSE DOWN ARND DPA SO MOVED THE TEMPO FOR THUNDER UP BY AN HOUR AT DPA. AS FAR AS THE TAFS ARE CONCERNED...FEELING MUCH MORE CONFIDENT IN TS IMPACTING THE TERMINALS BEFORE SUNRISE. KEPT A 2 HOUR WINDOW IN THE TAFS SINCE STILL NOT HIGHLY CONFIDENT IN WHEN THE TS WILL MAKE IT TO THE TERMINALS. ALSO KEPT A PERIOD OF RAIN BEHIND THE THUNDERSTORMS AS THE IA CONVECTION SHOULD CONSOLIDATE AND HAVE A REGION OF RAIN SHOWERS BEHIND IT. ODDS ARE THE RAIN WILL END SOONER THAN INDICATED IN THE TAFS. SOUTH WINDS ARND 10 KT ARE EXPECTED TOMORROW...WITH A LAKE BREEZE DEVELOPING IN THE AFTN. THINKING THE WIND SHIFT WILL BE SIMILAR TO YESTERDAY WITH A BRIEF PERIOD OF DUE EAST WINDS AND A MUCH LONGER PERIOD OF SE WINDS BEHIND THE LAKE BREEZE. THE LAKE BREEZE SHOULD MAKE IT THROUGH ALL OF THE EASTERN TERMINALS. THE LOW/TROUGH MOVES THROUGH TOMORROW WITH YET ANOTHER ROUND OF TSRA EXPECTED. THINKING TS IS PSBL AT RFD ARND 19Z AND THEN REACHING ORD BY 21Z. THE COMBINED FORCING OF THE TROUGH AND LAKE BREEZE COULD LEAD TO SOME VERY HEAVY RAINFALL AND MVFR VSBY. STILL NOT VERY CONFIDENT IN TIMING AND COVERAGE OF TS THIS AFTERNOON SO LEFT VCTS IN THE TAFS. WINDS WILL TURN NW TO W BEHIND THE TROUGH AND SKIES WILL BEGIN TO CLEAR OUT LATE IN THE EVENING. JEE //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH CONFIDENCE IN TSRA TONIGHT...MEDIUM CONFIDENCE WITH TIMING. * MEDIUM-LOW CONFIDENCE IN HOW MUCH AND HOW LONG RAIN WILL PERSIST BEHIND THE THUNDERSTORMS. * MEDIUM CONFIDENCE IN COVERAGE AND TIMING OF TSRA WEDNESDAY AFTERNOON. * MEDIUM CONFIDENCE IN TIMING OF LAKE BREEZE AND WINDS MAY BE MORE SE THAN FORECAST BEHIND THE LAKE BREEZE. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY AND FRIDAY...GENERALLY VFR OUTSIDE OF COUPLE OF BRIEF PERIODS OF THUNDERSTORMS. SATURDAY THROUGH MONDAY...GENERALLY VFR. A COUPLE OF BRIEF PERIODS OF SHOWERS. ED F && .MARINE... 150 AM CDT ELONGATED SFC LOW PRESSURE TROUGH OVER THE MID-UPPER MISSOURI VALLEY WILL MOVE SLOWLY EAST TODAY...WITH VARYING MODEL FORECASTS DEVELOPING A WEAK SURFACE LOW PRESSURE WAVE IN THE VICINITY OF NORTHERN IL/IND OR SOUTHERN LAKE MICHIGAN BY THIS EVENING. SOUTH TO SOUTHEAST WINDS SHOULD DIMINISH IN SPEED AS THE GRADIENT WEAKENS WITH THE APPROACH OF THE TROUGH THIS AFTERNOON...WITH LAKE BREEZE ESPECIALLY ALONG THE WESTERN SHORE. THUNDERSTORMS WILL BE POSSIBLE ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE...WHICH MAY RESULT IN SOME LOCALLY STRONGER WINDS. WINDS MAY BECOME SOMEWHAT VARIABLE AT 10 KT OR LESS TONIGHT AS THE SURFACE TROUGH/COLD FRONT MOVE SLOWLY ACROSS THE LAKE...EVENTUALLY TAKING ON A WEST- NORTHWEST DIRECTION THURSDAY AS THE TROUGH MOVES OFF TO THE EAST. SPEEDS SHOULD REMAIN GENERALLY LIGHT HOWEVER...WITH A RELATIVELY WEAK GRADIENT INTO FRIDAY. WEAK HIGH PRESSURE RIDGING WILL DEVELOP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS INTO THE WEEKEND...WHILE THE LOW PRESSURE WAVE EVENTUALLY DEEPENS EAST OF THE LAKES. THIS WILL MAINTAIN A PROLONGED PERIOD OF NORTH-NORTHWEST FLOW ACROSS LAKE MICHIGAN...THOUGH AGAIN WITH SPEEDS GENERALLY 15 KT OR LESS THROUGH THE PERIOD. OTHERWISE...IN THE NEAR TERM SOME PATCHY DENSE FOG WILL LINGER ACROSS THE NORTHERN PART OF THE LAKE THIS MORNING. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
113 AM CDT WED JUN 26 2013 .MESOSCALE DISCUSSION... MCV MENTIONED IN PREVIOUS UPDATE CONTINUES TO TRACK TO THE EAST- SOUTHEAST ACROSS THE CWA PER GOES SATELLITE EXTRAPOLATION. EXPECTATION IS THAT THIS CIRCULATION WILL MOVE OUT OF THE EAST/SOUTHEAST COUNTIES BY 10 PM CDT. CONVECTION WHICH CONTINUES TO BUBBLE OVER LAKE MICHIGAN/NORTHWEST INDIANA AND OVER THE SOUTH END OF THE LAKE WILL LIKELY CONTINUE FOR THE NEXT 1-2 HOURS AS THE MCV COMPLETES ITS TRANSIT OF THE AREA BEFORE MOVING EAST OF THE FORECAST AREA. SUBSIDENCE/STABILIZATION IN THE IMMEDIATE WAKE OF THIS FEATURE WILL LIKELY SUPPRESS NEW DEVELOPMENT ACROSS THE CENTRAL PART OF THE NRN IL CWA FOR A COUPLE OF HOURS...AND THEREFORE AFTER COLLABORATION WITH SPC HAVE DECIDED TO REMOVE LASALLE...KENDALL...GRUNDY AND WILL COUNTIES FROM SEVERE THUNDERSTORM WATCH 363. WHILE PREVIOUS CONVECTION HAS STABILIZED LOW LEVELS ACROSS THE SOUTHERN TIER OF OUR CWA COUNTIES IN 363...INCREASING SOUTHERLY LOW LEVEL JET AS NOTED IN VWP/S TO OUR WEST/SOUTHWEST HAS RESULTED IN DEVELOPMENT OF NEW DEEP/STRONG CONVECTION ACROSS WESTERN IL AND THESE STORMS MAY PERSIST ABOVE COLD POOL AND MAINTAIN A SEVERE THREAT INTO THE PONTIAC/KANKAKEE AREAS IN ANOTHER 1-2 HOURS. LOOKING FARTHER WEST...MID-LEVEL SHORT WAVE ACROSS THE MID-MISSOURI VALLEY WAS NOTED IN GOES VAPOR IMAGERY. LAST VIS IMAGES OF THE EVENING SHOW ACCAS FIELD OVER WESTERN/CENTRAL IA...WITH 3000-4000 J/KG OF MUCAPE INDICATED PER SPC/RAP MESOANALYSIS. CONVECTION ALLOWING MODELS INCLUDING WRF-NMM AND HRRR RUNS CONTINUE TO IMPLY THAT THE IA/WESTERN IL AREA WILL BECOME/REMAIN ACTIVE OVERNIGHT... WITH ONE OR MORE CLUSTERS OF STORMS POTENTIALLY AFFECTING PARTS OF THE CWA INTO EARLY WEDNESDAY MORNING. 23Z HRRR RUN SEEMS TO HAVE A REASONABLE HANDLE ON THIS SCENARIO...WITH ACTIVITY CURRENTLY DEVELOPING OVER WESTERN/CENTRAL IL PERHAPS AFFECTING OUR SOUTHERN COUNTIES THROUGH 05-07Z...THEN DEPICTING DEVELOPMENT OVER CENTRAL/EASTERN IA SPREADING ACROSS NRN IL DURING THE PRE-DAWN HOURS. HEAVY RAINFALL/SEVERE RISK CONTINUE OVERNIGHT...WITH WARM/MOIST AND UNSTABLE AIR MASS. RATZER && .DISCUSSION... 256 PM CDT SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT... THE ACTIVE WEATHER EXPECTED OVER THE NEXT 24 TO 30 HOURS...INCLUDING THE SEVERE WEATHER AND FLASH FLOODING THREAT WILL BE THE FOCUS OF THE SHORT TERM FORECAST. DUE TO THE INCREASING THREAT FOR PERIODS OF VERY HEAVY RAINFALL IN SLOW MOVING STORMS TONIGHT INTO WEDNESDAY...I HAVE EXTENDED THE FLASH FLOOD WATCH FOR THE ENTIRE AREA AND EXTENDED THROUGH WEDNESDAY. REGIONAL SATELLITE WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL DISTURBANCE CURRENTLY MOVING INTO NORTHWESTERN ILLINOIS. AREA VWP DATA ACROSS EASTERN IOWA AND SOUTHERN WISCONSIN INDICATE THAT THIS DISTURBANCE IS ASSOCIATED WITH A MID LEVEL SPEED MAX AROUND 50 KT. THIS IS RESULTING IN AROUND 40 KT OF 0-6 KM SHEAR...PER SPC MESO-ANALYSIS. THE AIR MASS AHEAD OF THIS FEATURE...ACROSS NORTHERN ILLINOIS...HAS BECOME INCREASINGLY UNSTABLE OVER THE PAST FEW HOURS...WITH SURFACE TEMPERATURES IN THE LOW TO MID 80S AND DEW POINTS IN THE LOWER 70S...ESPECIALLY TO THE SOUTH OF THE SURFACE BOUNDARY...CURRENTLY IN PLACE ACROSS FAR NORTHERN ILLINOIS. MODIFYING THE 12 UTC ILX SOUNDING...THIS RESULTS IN AROUND 3500 J/KG OF MLCAPE WITH LITTLE TO NO CAPE. NOT SURPRISING...THAT THUNDERSTORMS ARE BEGINNING TO FIRE ACROSS PORTIONS OF CENTRAL ILLINOIS AS ASCENT CONTINUES TO OVERSPREAD THIS UNSTABLE ENVIRONMENT. I EXPECT THIS TREND TO CONTINUE...ESPECIALLY ACROSS SOUTHERN SECTIONS OF THE AREA...WITH THE POTENTIAL OF AN ORGANIZING FORWARD PROPAGATING CONVECTIVE COMPLEX WITH STRONG DAMAGING WINDS BEING THE MAIN THREAT. HOWEVER...THE THREAT FOR SEVERE HAIL WILL ALSO BE A CONCERN...ESPECIALLY EARLY IN THE EVENT. THIS ACTIVITY WILL LIKELY CONTINUE INTO THE EARLY EVENING. ADDITIONAL ROUNDS OF CONVECTION ARE LIKELY AGAIN THIS EVENING AND OVERNIGHT...WITH THE POTENTIAL FOR SLOW MOVING AND BACK BUILDING THUNDERSTORMS. THE QUASI-ZONAL FLOW PATTERN ACROSS THE CONUS IS IN THE PROCESS OF AMPLIFYING...IN RESPONSE TO AN UPPER LOW OVER THE EASTERN PACIFIC. ULTIMATELY THIS WILL SET THE STAGE FOR A BUILDING MID/UPPER LEVEL RIDGE ACROSS THE WESTERN CONUS AND FALLING HEIGHTS ACROSS THE GREAT LAKES REGION. THIS PROCESS SHOULD ALLOW ANOTHER...STRONGER SHORT WAVE...CURRENTLY NOTED IN THE WATER VAPOR IMAGERY ACROSS THE PLAINS...TO MOVE ACROSS THE AREA BY WEDNESDAY. A SOUTHWESTERLY LOW LEVEL JET WILL KICK UP AHEAD OF THIS FEATURE DURING THE EVENING...AND GUIDANCE CONTINUES TO PLACE THE NOSE OF THIS LOW LEVEL JET RIGHT ACROSS THE AREA TONIGHT. THIS COULD POTENTIALLY LEAD TO A DECENT FLASH FLOODING EVENT FOR PORTIONS OF THE AREA TONIGHT INTO WEDNESDAY...WITH A GOOD POTENTIAL FOR SLOW MOVING AND BACK BUILDING THUNDERSTORMS. CORFIDI VECTORS ARE PROGGED TO BE 5 KT OR LESS TONIGHT AS THE JET VEERS WEST-SOUTHWESTERLY AND OFFSETS THE CLOUD BEARING FLOW. CONSIDERING THIS...AND THE FACT THAT FLASH FLOOD GUIDANCE REMAINS LOW ACROSS THE AREA...I DECIDED TO GO WITH A FLASH FLOOD WATCH FOR THE ENTIRE AREA. IT APPEARS THESE STORMS WITH HEAVY RAIN WILL CONTINUE INTO THE EARLY MORNING HOURS ON WEDNESDAY AND THEN INTENSIFY IN STRENGTH BY THE AFTERNOON...ESPECIALLY ACROSS MY SOUTHERN AND EASTERN AREAS. THIS COULD ALSO LEAD TO ADDITIONAL SEVERE STORMS...ESPECIALLY SOUTH. IT IS POSSIBLY THAT THE MORNING ACTIVITY COULD LIMIT THE SEVERE RISK TO THE NORTH. KJB LONG TERM...THURSDAY THROUGH TUESDAY... 350 PM CDT AMPLIFICATION OF THE WESTERN CONUS RIDGE AND EASTERN TROUGH WILL BEGIN TO INFLUENCE THE LOCAL AREA BY LATE WEDNESDAY INTO THURSDAY AFTER A SURFACE TROUGH PUSHES THROUGH THE AREA AND WINDS AT ALL LEVELS TURN TO THE NORTHWEST. LOW LEVEL WARMTH AND HUMIDITY DO NOT REALLY DEPART UNTIL FRIDAY WHEN THE EXPANDING EASTERN TROUGH PUSHES THE UPPER JET SOUTH OF THE AREA AND USHERS IN DRIER AND MILDER AIR. ON BOTH THURSDAY AND FRIDAY IT WOULD NOT TAKE MUCH OF A WRINKLE IN THE UPPER FLOW TO SUPPORT AN AFTERNOON SHOWER...SO SLIGHT CHANCE POPS HAVE BEEN MAINTAINED ON BOTH DAYS. BY THE WEEKEND THE CONVECTIVE INSTABILITY APPEARS TO HAVE DECREASED...BUT THE PRESENCE OF BOTH A SURFACE AND UPPER LEVEL TROUGH DROPPING SOUTH ACROSS THE AREA WILL STILL SUPPORT LARGE SCALE LIFT...PRIMARILY TO THE SOUTH ON SUNDAY. PRECIP CHANCES FINALLY DECREASE BY EARLY NEXT WEEK AS THE SURFACE AND UPPER SUPPORT DIMINISH...BUT UNSEASONABLY COOL AIR REMAINS IN PLACE WITH CONTINUED NORTH TO NORTHEASTERLY WINDS. LENNING JEE && .HYDROLOGY... REDEVELOPMENT OF THUNDERSTORMS LATER THIS AFTERNOON INTO TONIGHT IS LIKELY...WITH PERIODS OF HEAVY RAINFALL EXPECTED TO ACCOMPANY THESE THUNDERSTORMS. GUIDANCE CONTINUES TO FAVOR PRECIPITABLE WATER VALUES AROUND 2.00". ANOTHER DECENT MID LEVEL DISTURBANCE IS EXPECTED TO APPROACH THE AREA TONIGHT AND INTO WEDNESDAY...AND THIS SYSTEM LOOKS TO INDUCE A SOUTHWESTERLY LOW LEVEL JET...THAT COULD OFFSET THE FORWARD STORM MOTION...RESULTING IN SLOW MOVING OR BACK BUILDING THUNDERSTORMS TONIGHT INTO WEDNESDAY. AT THIS TIME...UNCERTAINTY REMAINS AS TO WHERE EXACTLY THE HEAVIEST RAIN WILL FALL...BUT GUIDANCE CONTINUES TO HINT AT NORTHERN ILLINOIS AND NORTHWESTERN INDIANA. THIS WILL HAVE TO BE WATCHED FOR POSSIBILITY OF A FLASH FLOOD WATCH FOR MOST OF THE AREA AS RAINFALL AMOUNTS IN EXCESS OF 2 INCHES IS CERTAINLY POSSIBLE ACROSS PORTIONS OF THE AREA. KJB/BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * TSRA LATE TONIGHT/EARLY WEDNESDAY MORNING. * HEAVY RAIN AND MVFR VSBY LIKELY WITH THE TSRA. * ADDITIONAL ROUND OF TSRA PSBL WEDNESDAY AFTERNOON. * LAKE BREEZE PSBL WEDNESDAY AFTERNOON WITH WINDS BCMG E. JEE //DISCUSSION...UPDATED 06Z... HIGH PRESSURE OVER THE SE US REMAINS IN PLACE WHILE A LOW OVER THE NORTHEASTERN PLAINS SLIDES THROUGH THE WESTERN GREAT LAKES LATER TODAY. CONVECTION IS CURRENTLY ON THE RADAR IN NORTHEAST IA AND EAST CENTRAL IL/SOUTHERN IN. THE CONVECTION TO THE SOUTH SHOULD REMAIN SOUTH OF THE TERMINALS. THE STORMS OVER IA ON THE OTHER HAND SHOULD CONTINUE EASTWARD BEFORE BEGINNING TO MOVE TOWARD THE SOUTHEAST. SCATTERED CONVECTION HAS ALSO BLOSSOMED AT THE NOSE OF THE LOW LEVEL JET IN NORTHWEST IL AND SHOULD CONTINUE TO SEE MORE SCATTERED CONVECTION. LASTLY...HAVE SEEN A FEW CELLS PULSE UP AND THEN PULSE DOWN ARND DPA SO MOVED THE TEMPO FOR THUNDER UP BY AN HOUR AT DPA. AS FAR AS THE TAFS ARE CONCERNED...FEELING MUCH MORE CONFIDENT IN TS IMPACTING THE TERMINALS BEFORE SUNRISE. KEPT A 2 HOUR WINDOW IN THE TAFS SINCE STILL NOT HIGHLY CONFIDENT IN WHEN THE TS WILL MAKE IT TO THE TERMINALS. ALSO KEPT A PERIOD OF RAIN BEHIND THE THUNDERSTORMS AS THE IA CONVECTION SHOULD CONSOLIDATE AND HAVE A REGION OF RAIN SHOWERS BEHIND IT. ODDS ARE THE RAIN WILL END SOONER THAN INDICATED IN THE TAFS. SOUTH WINDS ARND 10 KT ARE EXPECTED TOMORROW...WITH A LAKE BREEZE DEVELOPING IN THE AFTN. THINKING THE WIND SHIFT WILL BE SIMILAR TO YESTERDAY WITH A BRIEF PERIOD OF DUE EAST WINDS AND A MUCH LONGER PERIOD OF SE WINDS BEHIND THE LAKE BREEZE. THE LAKE BREEZE SHOULD MAKE IT THROUGH ALL OF THE EASTERN TERMINALS. THE LOW/TROUGH MOVES THROUGH TOMORROW WITH YET ANOTHER ROUND OF TSRA EXPECTED. THINKING TS IS PSBL AT RFD ARND 19Z AND THEN REACHING ORD BY 21Z. THE COMBINED FORCING OF THE TROUGH AND LAKE BREEZE COULD LEAD TO SOME VERY HEAVY RAINFALL AND MVFR VSBY. STILL NOT VERY CONFIDENT IN TIMING AND COVERAGE OF TS THIS AFTERNOON SO LEFT VCTS IN THE TAFS. WINDS WILL TURN NW TO W BEHIND THE TROUGH AND SKIES WILL BEGIN TO CLEAR OUT LATE IN THE EVENING. JEE //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH CONFIDENCE IN TSRA TONIGHT...MEDIUM CONFIDENCE WITH TIMING. * MEDIUM-LOW CONFIDENCE IN HOW MUCH AND HOW LONG RAIN WILL PERSIST BEHIND THE THUNDERSTORMS. * MEDIUM CONFIDENCE IN COVERAGE AND TIMING OF TSRA WEDNESDAY AFTERNOON. * MEDIUM CONFIDENCE IN TIMING OF LAKE BREEZE AND WINDS MAY BE MORE SE THAN FORECAST BEHIND THE LAKE BREEZE. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY AND FRIDAY...GENERALLY VFR OUTSIDE OF COUPLE OF BRIEF PERIODS OF THUNDERSTORMS. SATURDAY THROUGH MONDAY...GENERALLY VFR. A COUPLE OF BRIEF PERIODS OF SHOWERS. ED F && .MARINE... 234 PM CDT A LARGE RIDGE OF HIGH PRESSURE WILL PERSIST ACROSS THE SOUTHEAST STATES THROUGH MID WEEK WHILE A TROUGH OF LOW PRESSURE OVER THE CENTRAL PLAINS SHIFTS INTO THE UPPER MISSOURI VALLEY THIS EVENING AND THE UPPER MISSISSIPPI VALLEY WEDNESDAY. THIS WILL KEEP GENERALLY SOUTHERLY WINDS OVER THE LAKE THROUGH WEDNESDAY. THE TROUGH WILL THEN DRIFT ACROSS LAKE MICHIGAN WEDNESDAY EVENING...WITH WINDS GRADUALLY SHIFTING TO MORE NORTHERLY. THE SOUTHERN END OF THE TROUGH WILL CLOSE OFF INTO A CLOSED LOW OVER THE EASTERN GREAT LAKES THURSDAY AFTERNOON AND TRACK NORTH INTO SOUTHERN QUEBEC BY FRIDAY NIGHT. A SECONDARY SURGE OF COOLER AIR WILL PUSH ACROSS THE LAKE INCREASING WINDS TO 15 TO 20 KT. NORTHERLY WINDS OF 10 TO 15 KT WILL PERSIST OVER THE LAKE THROUGH THE END OF THE PERIOD. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 7 PM WEDNESDAY. IN...FLASH FLOOD WATCH...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1207 AM CDT WED JUN 26 2013 .DISCUSSION... ISSUED 900 PM CDT TUE JUN 25 2013 THE STORMS HAVE BECOME LESS NUMEROUS IN COVERAGE OVER THE LAST COUPLE OF HOURS...ALTHOUGH INDIVIDUAL CLUSTERS OF STORMS HAVE MAINTAINED SOME VIGOROUS UPDRAFTS WITH LARGE AMOUNTS OF MOISTURE ALOFT AND VERY HEAVY RAINFALL AND SOME HAIL. WITH COOLING OF SURFACE TEMPS...WE ARE LOSING SURFACE BASED CAPE. HOWEVER...STORMS APPEAR TO BE SURVIVING BY BECOMING ELEVATED...WITH A CONTINUED THREAT OF VERY HEAVY RAIN AND SOME HAIL...BUT LOWER CHANCES OF WIND DAMAGE. AS FOR THE TRENDS FOR THE REST OF THE NIGHT...WITH EACH SUCCESSIVE HOUR OF THE HRRR MODEL...IT HAS SLOWED DOWN THE ARRIVAL OF OUR LATE NIGHT CONVECTIVE COMPLEX FROM IOWA. IT HAS PICKED UP ON THE RENEWED CONVECTION IN OUR WESTERN COUNTIES AND IT SHOWS THEM PROGRESSING TO THE NORTHEAST THEN EAST. A LARGER COMPLEX OF STORMS IS STILL INDICATED TO ARRIVE IN OUR NW COUNTIES FROM THE NORTHWEST TOWARD 11Z/6AM. WILL KEEP AND EYE ON TIMING BASED ON SATELLITE AND RADAR TRENDS...BUT FOR NOW WILL ADJUST LIKELY POPS TO LATER TONIGHT FOR THE NW COUNTIES. WILL ALSO ADJUST THE WED MORNING LIKELY POPS BACK TO THE NORTHWEST INSTEAD OF JUST SOUTHEAST OF I-70. WE MAY BE SEEING THE HRRR CONTINUE TO ADJUST THE TIMING OF THE NEXT COMPLEX UNTIL IT BECOMES OUR MAIN SEVERE WEATHER PRODUCER DURING THE DAY ON WEDNESDAY. UPDATED WEATHER INFORMATION IS ALREADY AVAILABLE. && .AVIATION... ISSUED 1205 AM CDT WED JUN 26 2013 MAIN EMPHASIS IN THIS FORECAST PERIOD CONTINUES TO REVOLVE AROUND CONVECTION COVERAGE AND AFFECT ON CIGS AND VSBYS. LATEST SHORT TERM MODELS CONTINUE TO SUGGEST ANOTHER COMPLEX OF STORMS DEVELOPING ACROSS IOWA THEN TRACKING E/SE INTO CENTRAL ILLINOIS TOWARD DAWN. WILL CARRY PREDOMINANT THUNDER AFTER 11Z AT KPIA...THEN AFTER 13Z FURTHER EAST AT KDEC. AFTER A 3-4 HOUR PERIOD OF CONVECTION WEDNESDAY MORNING...A LULL IN THE ACTIVITY MAY DEVELOP. DUE TO UNCERTAINTY...WILL CONTINUE TO ONLY MENTION VCTS FROM MID MORNING THROUGH MID-AFTERNOON WHEN COLD FRONT PUSHES THROUGH THE AREA AND SHIFTS BETTER STORM CHANCES FURTHER EAST INTO INDIANA. WINDS WILL BE SOUTHERLY AT LESS THAN 10KT TONIGHT...THEN WILL BECOME WESTERLY BY WEDNESDAY AFTERNOON WITH SPEEDS AROUND 10 KTS WITH WIND DIR/SPEED QUITE VARIABLE IN AND NEAR TSRA. SMITH && .PREV DISCUSSION... ISSUED 300 PM CDT TUE JUN 25 2013 SEVERE STORM CHANCES WILL REMAIN THE FOCUS OVER THE NEXT 2 DAYS. FLASH FLOODING POTENTIAL TONIGHT IN THE NORTH WILL ALSO BE A CONCERN. BEYOND THAT...AN AIRMASS CHANGE IS PROJECTED FOR LATE THIS WEEK AND WEEKEND. HOWEVER...A CUTOFF UPPER LOW LINGERING OVER THE HEARTLAND WILL KEEP SHOWERS AND EVEN ISOLATED THUNDERSTORMS IN THE FORECAST THROUGH EARLY NEXT WEEK. SHORT TERM...TONIGHT THROUGH FRIDAY. WE DECIDED TO PUT OUR 5 NORTHERN COUNTIES IN A FLASH FLOOD THROUGH TONIGHT DUE TO PREVIOUS 3-5 INCH RAINS EARLY MONDAY MORNING AND THE POTENTIAL FOR ADDITIONAL VERY HEAVY RAINFALL RATES UP TO 2 INCHES AN HOUR WITH ANY THUNDERSTORMS THROUGH TONIGHT. PWATS REMAIN IN THE 1.7-1.9" RANGE...AND PERIODIC STORMS IN AN EAST-WEST LINE ACROSS N IL IS POSSIBLE. ADJUSTING OUR 12Z SOUNDING FOR CURRENT CONDITIONS SHOWS ML-CAPE VALUES APPROACHING 3500 J/KG ACROSS OUR AREA...WITH LITTLE TO NO CIN. VARIOUS BOUNDARIES ACROSS THE AREA FROM YESTERDAYS CONVECTION HAVE ALREADY BEGUN TO FIRE BETWEEN 18-19Z. WATER VAPOR PIX CONFIRM A SHORTWAVE IN THE FLOW ACROSS IOWA PROGRESSING EAST-NE. THAT WAVE SHOULD HELP RAMP UP THE COVERAGE OF STORMS AND POSSIBLY PUSH US INTO SEVERE WEATHER MODE. FREEZING LEVEL AT 14.4K FT MEANS HAIL WILL NEED INTENSE UPDRAFTS TO REACH SEVERE LEVELS /1"+/...BUT WE HAVE THE CAPE TO ACCOMPLISH THAT WITH THE STRONGEST STORMS. WIND SHEAR WILL BE GRADUALLY INCREASING AS WE HEAD INTO THIS EVENING...SO ROTATING SUPERCELLS WILL BE POSSIBLE AS THE EVENT PROGRESSES. THE LATEST HRRR IS INDICATING TWO PERIODS OF STORMS POSSIBLE. WE EXPECT A WAVE OF STORMS THIS EVENING THAT MAY BE FOLLOWED BY ANOTHER BOWING COMPLEX OF STORMS ROLLING INTO OUR AREA FROM IOWA REACHING KNOX COUNTY AROUND 06Z/1AM. THOSE STORMS MAY BE STILL AFFECTING OUR COUNTIES SE OF I-70 WED MORNING BEFORE THEY DEPART INTO INDIANA. WE WENT WITH SOME LIKELY POPS IN THE MORNING TO ACCOUNT FOR THAT. THEN A BREAK IN THE ACTION MAY DEVELOP THE REST OF WED MORNING AS THE ATMOSPHERE RECHARGES FOR THE AFTERNOON WAVE OF STRONG TO SEVERE STORMS. IT APPEARS THAT A LINE OF STORMS WILL DEVELOP ACROSS WEST CENTRAL ILLINOIS BY MID AFTERNOON...THEN PROGRESS EASTWARD. AN INCREASING LLJ IS EXPECTED TO COINCIDE WITH UPPER LEVEL WINDS VEERING TO THE NORTHWEST. THAT WILL INCREASE SHEAR AND HELICITY PARAMETERS AND RAMP UP THE THREAT OF ROTATING STORMS AND POSSIBLY A FEW TORNADOES...MAINLY EAST OF I-55. WE INCREASED POPS TO LIKELY IN THE EAST WEDNESDAY AFTERNOON TO ACCOUNT FOR THAT PERIOD OF SEVERE STORMS. STORMS SHOULD BE WINDING DOWN WED EVENING AS THE COMPLEX MOVES INTO INDIANA. THURSDAY AND THURSDAY NIGHT SHOULD BE PRIMARILY DRY...BUT A FEW DAYTIME SHOWERS WILL BE POSSIBLE IN THE EAST AS THE UPPER WAVE LINGERS ACROSS THE EAST...AND A FEW SHOWERS MAY REACH OUR SOUTHWESTERN COUNTIES THUR NIGHT AHEAD OF THE NEXT UPPER LEVEL WAVE. WE KEPT SLIGHT CHANCE POPS EVERYWHERE ON FRIDAY AS THAT WAVE PROGRESSES ACROSS IL. PRECIP SHOULD BE SPOTTY...AS COOLER AND LESS HUMID AIR BEGINS TO FLOW INTO THE AREA ON NORTHWEST WINDS. LONG TERM...SATURDAY THROUGH TUESDAY. WE EXPECT TO BE IN AN EXTENDED PERIOD UP UPPER LEVEL TROUGHING AS A CUT OFF LOW DEVELOPS ACROSS THE WESTERN GREAT LAKES AND RETROGRADES AND OSCILLATES OVER THE MIDWEST THROUGH EARLY NEXT WEEK. PERIODS OF SLIGHT CHANCE AND CHANCE POPS WILL PEPPER THE EXTENDED FORECAST AS A RESULT...DUE TO VARIOUS SHORTWAVE ROTATING AROUND THE UPPER LOW. RELATIVELY COOL AIR ALOFT WILL ALSO KEEP LAPSE RATES MODERATELY HIGH...AND FAVORABLE FOR ANY SUNS HEATING TO CREATE SHOWERS AND ISOLATED STORMS. TEMPS WILL SETTLE OUT WITH HIGHS IN THE UPPER 70S TO NEAR 80 AND LOWS IN THE LOWER 60S FOR MUCH OF THE EXTENDED PERIOD. && .ILX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 7 AM CDT THIS MORNING FOR ILZ027>031. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
337 PM CDT WED JUN 26 2013 .SYNOPSIS... ISSUED AT 334 PM CDT WED JUN 26 2013 18Z SFC ANALYSIS HAS THE REMNANTS OF A MESO HIGH AT KDBQ AND A MESO LOW BETWEEN KSQI AND KFEP. AN OUTFLOW BOUNDARY FROM THE MCS RAN FROM LAKE MICHIGAN THROUGH CENTRAL ILLINOIS AND THEN TO NEAR KMXO. THE SYNOPTIC COLD FRONT RAN FROM NEAR KMSP...TO KDSM...TO KFNB. AHEAD OF THE SYNOPTIC FRONT SEVERAL WEAK TROFS/BOUNDARIES WERE ACROSS EASTERN IOWA AND MISSOURI. DEW POINTS WERE IN THE 70S WITH 60S OVER THE GREAT LAKES AND BEHIND THE COLD FRONT. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 334 PM CDT WED JUN 26 2013 DIURNAL CONVECTION HAS FIRED ALONG A THETA E GRADIENT IN CENTRAL IOWA AND ALONG A PRE-FRONTAL TROF. RAP TRENDS BRING THIS FEATURE INTO THE WESTERN CWFA LATE THIS AFTERNOON BEFORE WEAKENING THE THETA E GRADIENT. THUS THE NEW STORMS THAT HAVE DEVELOPED JUST WEST OF THE CWFA ARE EXPECTED TO MOVE INTO THE WESTERN CWFA DURING THE LATE AFTERNOON HOURS AND THEN SLOWLY DISSIPATE WITH SUNSET. AHEAD OF THIS CONVECTION...ISOLATED SHOWERS AND STORMS ARE EXPECTED TO DEVELOP DURING PEAK HEATING THAT WILL ALSO SLOWLY DISSIPATE WITH SUNSET. THE SYNOPTIC COLD FRONT WILL MOVE THROUGH THE CWFA TONIGHT DROPPING DEW POINTS ABOUT 5 TO 7 DEGREES. WINDS ARE EXPECTED TO BE FAIRLY LIGHT AND GIVEN THE WET GROUND IN SOME AREAS THERE IS A POTENTIAL FOR SOME FOG DEVELOPMENT AFTER MIDNIGHT. THIS WILL HAVE TO BE WATCHED TO SEE HOW IT WILL EVOLVE. QUIET AND DRY CONDITIONS WILL BE SEEN THURSDAY MORNING ACROSS THE AREA WHILE AN UPPER LOW MOVES INTO THE NORTHERN GREAT LAKES. DAY TIME HEATING COMBINED WITH SLIGHTLY COOLER AIR ALOFT SHOULD ALLOW NEW CONVECTION TO DEVELOP DURING THE AFTERNOON. THE LOWER MOISTURE LEVELS IN THE ATMOSPHERE AND NORTHWEST FLOW SHOULD RESULT IN THE CONVECTION BEING ISOLATED TO SCATTERED IN NATURE. ..08.. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 334 PM CDT WED JUN 26 2013 THURSDAY NIGHT AND FRIDAY...AS NORTHWESTERLY STEERING FLOW TAKES OVER WITH UPPER RIDGE RETROGRADE...DIGGING UPPER WAVE INTO THE NORTHWESTERN GRT LKS WILL CONNECT WITH TROF INTO THE CENTRAL PLAINS FOR CONTINUED ISOLATED TO WDLY SCTRD SHOWER/STORM THREAT INTO MID THU EVENING. BUT BEST FORCING AND CONVERGENCE TO REMAIN JUST TO THE NORTHEAST AND SOUTHWEST OF THE DVN CWA. WILL EXTEND LOW CHC POPS IN THE FAR EAST AND MAINTAIN ONGOING POPS IN THE SOUTHWESTERN CWA THROUGH 03Z FRI. AFTER TROF EMBEDDED IN NW STEERING FLOW PASSES...EXPECT SOME CLEARING AND COOLER CONDITIONS INTO EARLY FRI MORNING WITH LOWS WELL DOWN INTO THE 60S...POSSIBLY SOME LOWER 60S NORTH OF I80. LARGE UPPER CYCLONE COMPLEX TO THEN CONTINUE TO SETTLE ACRS THE HEART OF THE GRT LKS ON FRI. ASSOCIATED VORT SPOKE ALOFT AND MID LEVEL COOL POOL TO INDUCE DEEP STEEP LAPSE RATES AND A INSTABILITY SHOWER SET UP ACRS MN INTO WI AND IL. SOME POTENTIAL FOR THUNDERSTORMS WITH VERTICAL THERMODYNAMIC PROFILES SUPPORTIVE OF HAIL IF ENHANCED UPDRAFTS CAN MAINTAIN. THIS ACTIVITY MORE LIKELY FRIDAY AFTERNOON ACRS THE NORTHEASTERN THIRD OF THE DVN CWA AND WILL ADJUST POPS ACCORDINGLY. DESPITE INCOMING COOLER AIR INFLUX/ ADVECTION...DEEP MIXING PROFILES UP TO H8 MB STILL TO BOOST TEMPS INTO THE LOW TO MID 80S WHILE SFC DPTS DRY-DOWN MIX INTO THE LOWER 60S TO UPPER 50S...MAYBE LOWER THAN GUIDANCE SUGGESTS INTO THE MID 50S. BREEZY NORTHWEST WINDS AS WELL IN THIS SCENARIO OF 15 TO 20+ MPH. TIGHTENING CYCLONIC FLOW ALOFT MAY KEEP SHOWERS PECULATING WELL INTO FRI EVENING BEFORE NOCTURNAL PROCESSES TAKE OVER. EVEN WITH CLOUD DEBRIS...STILL A COOLER NIGHT WITH WIDESPREAD LOWS IN THE LOW TO MID 60S. SATURDAY AND SUNDAY...UNSTABLE VERTICAL PROFILES UNDER ONGOING CYCLONIC FLOW AND ANOTHER INCOMING VORT SPOKE MAY PRODUCE MORE WIDESPREAD SHOWERS AND A FEW STORMS/FURTHER TO THE WEST/THEN ON FRIDAY. CANADIAN LLVL RIDGE AXIS DUMPING DOWN TO THE WEST OF THE AREA ACRS THE PLAINS. FCST SOUNDING SUGGEST ANOTHER DAY OF DEEP MIXING... BUT CONTINUED LLVL COOL POOL INFLUX AS WELL AS SHOWERS/CLOUDS WILL HAVE A BETTER SHOT TO KEEP TEMPS IN THE 70S. CLEAR OUT SAT NIGHT AS LARGE STOUT CANADIAN HIGH TAKES GRIP OF THE UPPER MIDWEST AND COULD FOSTER WIDESPREAD LOWS WELL DOWN IN THE 50S BY EARLY SUNDAY MORNING. HIGH PRESSURE TO THEN TO MIGRATE TOWARD THE GRT LKS ON SUNDAY...WHILE ALOFT DEEP LONG WAVE TROF EXTENDS TO THE GULF ALONG AND EAST OF THE MS RVR VALLEY. APPEARS LESSENING CHANCE OF SHOWERS SUNDAY AND BOUNDARY LAYER NORTHEASTERLY FETCH AGAIN TO POSSIBLY KEEP TEMPS IN THE 70S FOR HIGHS. SUNDAY NIGHT SEASONABLY COOL AND WELL DOWN IN THE 50S ALONG AND NORTH OF I80. MONDAY THROUGH NEXT WEDNESDAY...LONG RANGE SIGNALS SUGGEST A GENERAL BLOCKED PATTERN WITH BOOKEND RIDGES ON THE COASTS AND MID CONUS L/W TROFFINESS PERSISTING THROUGH WED. BUT THEY ALSO SUGGEST IT TO START TO MODIFY AND BREAK DOWN THE L/W TROF FEATURE AFTER TUE. THUS IN GENERAL...BELOW NORMAL TEMPS LOOK TO CONTINUE IN THE VCNTY OF THIS UPPER TROF..AS WELL AS ALMOST A DAILY THREAT OF POP UP SHOWERS AND A FEW STORMS. BETTER CHANCES OFF THOUGH TO THE SOUTHEAST OF THE DVN CWA IN VCNTY OF UPPER LOW MON INTO TUE. ..12.. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1225 PM CDT WED JUN 26 2013 DIURNAL CONVECTION HAS DEVELOPED OVER CENTRAL IOWA AHEAD OF THE COLD FRONT. THIS CONVECTION WILL MOVE INTO EASTERN IOWA AND SLOWLY DISSIPATE WITH SUNSET. HIGH MOISTURE LEVELS IN THE ATMOSPHERE HAS RESULTED IN SOME MVFR CIGS TO DEVELOP. IF A TSRA WOULD IMPACT A TAF SITE A BRIEF PERIOD OF IFR CONDITIONS WILL BE POSSIBLE. AFT SUNSET VFR CONDITIONS ARE EXPECTED. HOWEVER...THE WET GROUND AND LIGHT WINDS MAY ALLOW FOG TO DEVELOP AFT 06Z/27. IF THIS OCCURS...THERE IS A POTENTIAL FOR IFR/LIFR CONDITIONS. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...08 SHORT TERM...08 LONG TERM...12 AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1233 PM CDT WED JUN 26 2013 .UPDATE... ISSUED AT 1225 PM CDT WED JUN 26 2013 THE NOCTURNAL MCS HAS DISSIPATED ACROSS ILLINOIS. BOUNDARIES LEFT OVER FROM THIS CONVECTION ALLOWED NEW CONVECTION TO DEVELOP THIS MORNING BEFORE DOWNWARD MOTION FROM THE MCV CAUSED IT TO ALSO DISSIPATE. WATER VAPOR SHOWS A RESPECTABLE VORT MAX MOVING FROM MINNESOTA INTO IOWA. RAP TRENDS INDICATE DOWNWARD MOTION WILL CONTINUE INTO THE EARLY AFTERNOON BEFORE LIFT FROM THE APPROACHING VORT MAX INCREASES. THIS LIFT MAY BE ENOUGH WHEN COMBINED WITH THE APPROACHING COLD FRONT TO ALLOW ISOLATED TO SCATTERED CONVECTION TO DEVELOP MID TO LATE AFTERNOON. ..08.. UPDATE ISSUED AT 1000 AM CDT WED JUN 26 2013 THE NOCTURNAL MCS THAT PRODUCED THE EXTREMELY HEAVY RAINFALL IS RAPIDLY DECAYING ACROSS ILLINOIS. COLD POOLS AND OUTFLOW BOUNDARIES FROM THE MCS IS PROVIDING A FOCUS FOR NEW CONVECTION ACROSS IOWA. WATER VAPOR SHOWS A RESPECTABLE VORT MAX DIVING SOUTHEAST INTO IOWA FROM MINNESOTA WHICH IS HELPING TO DRIVE SOME OF THE CONVECTION. DOWNWARD MOTION BEHIND THE DECAYING MCS IS HELPING TO DISSIPATE THE NEW CONVECTION ACROSS IOWA. HOWEVER...RAP TRENDS SHOW LIFT WILL BE ON THE INCREASE AGAIN BY LATE MORNING AND INTO THE AFTERNOON. SO...CONVECTION IS EXPECTED TO PERSIST AND MAY EXPAND SOME IN AREAL COVERAGE DURING THE AFTERNOON. ..08.. && .SYNOPSIS... ISSUED AT 335 AM CDT WED JUN 26 2013 AS OF 08Z LOW PRESSURE WAS FOUND IN WESTERN IOWA...WITH TROUGH EXTENDING NORTH INTO THE RED RIVER VALLEY AND COLD FRONT TRAILING OFF TO THE SW INTO KANSAS. TWO DIFFUSE WARM FRONTAL BOUNDARIES WERE FOUND ALONG NORTHERN PARTS OF CWFA AND JUST TO THE SOUTH. AN MCV WAS SEEN ON RADAR JUST SW OF DUBUQUE WITH A LINE OF STORMS EXTENDING SW TO NEAR IOWA CITY. THIS LINE WAS STARTING TO INDICATE SOME BOWING AGAIN. ADDITIONAL CONVECTIVE ACTIVITY LINGERS TO THE NW WHERE STORMS HAD EARLY SAT STILL CAUSING SOME FLASH FLOODING IN BUCHANAN COUNTY AND NORTHERN LINN COUNTY. DEW POINTS ARE MAINLY IN THE MID 60S TO LOWER 70S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT WED JUN 26 2013 FOCUS ON SHORT TERM IS IN WALKING OUT THIS EARLY MORNING CONVECTION. MAINLY TURNING OUT TO BE HEAVY RAIN EVENT...WITH SOME MARGINALLY SEVERE WIND GUSTS POSSIBLE IN BOWING PHASES AS THE LINE MOVES ACROSS EAST CENTRAL IOWA AND NW ILLINOIS...GENERALLY ALONG AND NE OF A LINE FROM WASHINGTON IOWA...TO MACOMB ILLINOIS. EXPECT ACTIVITY TO DIMINISH THROUGH THE MORNING HOURS AS LOW MOVES ACROSS THE AREA AND SUBSIDENCE ON NW FLOW WORKS INTO THE AREA BEHIND THE DEPARTING STORMS. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 335 AM CDT WED JUN 26 2013 NOT MUCH CHANGE TO THE EXTENDED FORECAST WHICH IS RELATIVELY QUIET FOR A CHANGE...COOLER...AND LESS HUMID. A TROUGH DIGS ACROSS THE EAST COAST WHILE A RIDGE BUILDS...WITH THE CWFA IN NW FLOW THROUGH THE PERIOD. WEAK DISTURBANCES WILL MOVE ACROSS THE AREA...WITH ONLY SLIGHT/LOW END CHANCE POPS ATTM. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1225 PM CDT WED JUN 26 2013 VFR WX IS EXPECTED THROUGH 02Z/27. DOWNWARD MOTION BEHIND THE DISSIPATED TSRA COMPLEX WILL SUPPRESS NEW CONVECTION UNTIL AFT 20Z/26. PROBABILITY OF A TSRA AFFECTING A TAF SITE IS LOW BUT VCTS WAS INCLUDED IN THE 18Z TAFS. AFT 02Z/27 VFR WX SHOULD CONTINUE. LIGHT WINDS AND WET GROUND MAY RESULT IN FOG DVLPG AFT 06Z/27. IF THIS OCCURS...MVFR CONDITIONS WOULD BE SEEN WITH A POTENTIAL FOR IFR/LIFR CONDITIONS. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...14 SHORT TERM...14 LONG TERM...14 AVIATION...08
AREA FORECAST DISCUSSION
NWS TOPEKA KS
329 AM CDT WED JUN 26 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 305 AM CDT WED JUN 26 2013 0Z UPPER AIR OBSERVATIONS SHOWED A RATHER SHARP MID LEVEL WAVE OVER THE MISSOURI RIVER WITH A NARROW AXIS OF WARM AIR ADVECTION AHEAD OF IT AND ELEVATED CONVECTION BLOSSOMED OVERNIGHT IN NORTHERN MISSOURI. A VERY MODIFIED COLD FRONT WITH THIS WAVE WAS BISECTING KANSAS FROM SOUTHWEST TO NORTHEAST AT 07Z. NEARBY 0Z 850MB TEMPS WERE 20C AT KTOP...26C BEHIND THE FRONT AT KLBF...AND 31C AND KDDC. RECENT AREA PROFILERS AND RADARS INDICATE MODERATE WESTERLY FLOW AT THIS LEVEL BRINGING WARMER AIR INTO EASTERN KANSAS. MID LEVEL SUBSIDENCE BEHIND THE WAVE AND WEAK LOW LEVEL CONVERGENCE SHIFTING SOUTHEAST OF EAST CENTRAL KANSAS BY EARLY AFTERNOON SHOULD KEEP ANY PRECIP IN CHECK FOR TODAY AND TONIGHT. 850MB TEMPS SHOULD BE A FEW DEGREES WARMER THIS AFTERNOON ESPECIALLY IN EASTERN LOCATIONS WITH HIGHS SEVERAL DEGREES WARMER THERE IN ORDER COMPARED TO THE TUESDAY. NORTHERLY LOW LEVEL FLOW BEHIND THE MODIFIED FRONT SHOULD KEEP AFTERNOON DEWPOINTS IN THE 60S FOR THE MOST PART AND HEAT INDICES BELOW EXTREME VALUES. LIGHT WINDS AND ONLY SOME CIRRUS EXPECTED TONIGHT WITH WEAK SURFACE HIGH NEARBY. DROPPED LOWS A FEW DEGREES WITH THESE FEATURES IN MIND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 305 AM CDT WED JUN 26 2013 THURSDAY LIKELY TO BRING BOTH THE THE HOTTEST DAY OF THE WEEK TO THE AREA AS WELL AS THE GREATEST RISK FOR SEVERE WEATHER. 850MB THERMAL RIDGE NOSES EASTWARD ACROSS THE STATE WITH NEAR 30C AT THE WESTERN FRINGES OF THE CWA. TEMPERATURES OUT IN THE WESTERN COUNTIES EXPECTED TO TOP 100 ALONG/WEST OF MANHATTAN WITH UPPER 90S EASTWARD. EVEN WITH MIXING DOWN SOME DRIER DEWPOINTS...HEAT INDICES STILL RUNNING 104 TO 106 FOR THE ENTIRE AREA. SEVERE THREAT INCREASES AS A POTENTIAL MCS IS PROGGED TO DEVELOP OVER NEBRASKA ALONG THE THERMAL GRADIENT ON THE NOSE OF THE LLJ BY 12Z...AND PROPAGATE SOUTHEAST AS THE JET VEERS ALONG THE BOUNDARY INTO NE KS / WRN MO. SURFACE FRONT ALSO ASSOCIATED WITH THIS FEATURE MOVES SOUTHWARD THROUGH THE FA DURING PEAK HEATING. CONCERNS ARE THAT CONSIDERABLE DRY AIR DEEP IN THE BOUNDARY LAYER COUPLED WITH AVAILABLE INSTABILITY OF 1500-3000K/KG ATOP INVERTED V SOUNDINGS MAY BRING A SIGNIFICANT WIND THREAT FROM ANY CONVECTION THAT DEVELOPS OVER EASTERN KS IN THE AFTERNOON AND EVENING HOURS. WILL MONITOR AS CONDITIONS DEVELOP. INCOMING HIGH PRESSURE FRIDAY STILL ON THE WARM LEADING EDGE OF THE HIGH...AND TEMPERATURES STILL EXPECTED TO REACH LOWER 90S IN ABUNDANT SUNSHINE AND GOOD MIXING. PATTERN THEN SETS UP FOR A COOL LATE JUNE EARLY JULY PATTERN AS WESTERN RIDGE AMPLIFIES AND ENERGY ROTATING AROUND THE PERIPHERY INTO THE EASTERN TROF STRENGTHENS THE AMPLIFICATION IN THE PATTERN...LEAVING PLAINS STATES IN NORTHERLY FLOW THROUGH THE END OF THE FORECAST PERIOD. AS COMPARED TO THE FORECAST HOT WEATHER FOR THURSDAY...850MB TEMPS ARE PROGGED TO BE 14C BY NEXT TUESDAY AFTERNOON...WITH HIGHS FORECAST IN THE LOWER 80S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1122 PM CDT TUE JUN 25 2013 WITH WATER VAPOR SHOWING AN UPPER LEVEL TROUGH PASSING EAST OF THE MO RIVER AND THE DIURNALLY DRIVEN CONVECTION IN SOUTH CENTRAL KS DISSIPATING...THINK VFR CONDITIONS WILL PREVAIL OVERNIGHT. BOTH THE NAM AND RAP SHOW THE BEST COMBINATION OF ISENTROPIC UPGLIDE AND SATURATION TO REMAIN OVER NORTHERN MO AND MOVING TO THE EAST OVERNIGHT. WITH NEW ELEVATED STORMS ALREADY EAST OF THE MO RIVER...IT IS HARD TO SEE ANYTHING FORMING IN KS. WINDS SHOULD GRADUALLY DIMINISH OVERNIGHT AS THE SFC LOW CONTINUES TO FILL AND THE PRESSURE GRADIENT WEAKENS. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...67 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1122 PM CDT TUE JUN 25 2013 .UPDATE... ISSUED AT 726 PM CDT TUE JUN 25 2013 HAVE UPDATED THE FORECAST TO TAKE OUT THE SLIGHT CHANCE OF THUNDERSTORMS FOR THE EARLY EVENING. SURFACE OBS AND LAPS ANALYSIS SHOWS THE STRONGER LOW LEVEL CONVERGENCE BETWEEN MCPHERSON AND PRATT ALONG THE SURFACE BOUNDARY. ISOLATED CONVECTION HAS FORMED IN THIS AXIS OF LOW LEVEL CONVERGENCE. WITH THE LOW LEVEL MOISTURE FLUX LESS IMPRESSIVE ACROSS NORTH CENTRAL KS AND THE CU FIELD SHOWING LITTLE VERTICAL DEVELOPMENT OUTSIDE OF THE ENHANCED CONVERGENCE NEAR HUTCHINSON...THINK ADDITIONAL DEVELOPMENT IS UNLIKELY AS THE BOUNDARY LAYER STARTS TO STABILIZE WITH THE LOSE OF DAY TIME HEATING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 343 PM CDT TUE JUN 25 2013 LATEST WATER VAPOR LOOP SHOWS A WAVE MOVING ACROSS WESTERN KANSAS. SPEED LOOP OF VISIBLE SATELLITE SHOWS SOME CIRCULATION OVER NORTH CENTRAL KANSAS WITH A CU FIELD TO ITS EAST AND NORTHEAST. SURFACE TROUGH FROM A LOW IN SOUTHWEST KANSAS NORTHEAST INTO NEBRASKA. LATEST MESO ANALYSIS CONTINUES TO SHOW DEEP MOISTURE OVER EASTERN KANSAS. DEEP MOISTURE CONVERGENCE WAS OCCURRING OVER NORTHEAST AND NORTH CENTRAL KANSAS AHEAD OF THE ABOVE MENTIONED FEATURE. EML WAS WORKING ITS WAY ACROSS SOUTH CENTRAL KANSAS THIS AFTERNOON WHERE 15 DEGREE CELSIUS AIR RESIDES. THE HRRR AND WRF SHOW SOME ISOLATED CONVECTION DEVELOPING NORTH OF I-70 LATE THIS AFTERNOON AND EVENING IN NORTH CENTRAL AND NORTHEAST KANSAS. HAVE ONLY ABOUT A 10 TO 15 PERCENT CHANCE OF A THUNDERSTORM IN THE FORECAST FOR A FEW HOURS THIS EVENING. ATMOSPHERE REMAINS UNSTABLE WITH LITTLE TO NO CONVECTIVE INHIBITION. 0-6KM SHEAR NEAR 40 KTS SO COULD SEE A SUPERCELL OR TWO DEVELOP. LOW LEVEL JET VEERS TONIGHT WITH THE DEEPER MOISTURE MOVING OFF TO THE EAST. A COLD FRONT IN THE WESTERN PLAINS WILL MOVE SOUTHEAST AND ACROSS NORTH CENTRAL AND NORTHEAST KANSAS LATER TONIGHT THROUGH MID DAY WEDNESDAY. SURFACE HIGH PRESSURE WILL MOVE IN BEHIND THE FRONT ON WEDNESDAY. TEMPERATURES WILL BE MILD AGAIN TONIGHT WITH LOWS MAINLY IN THE 70S. HIGHS ON WEDNESDAY WILL BE IN THE MID 90S IN THE NORTHEAST CORNER TO NEAR 100 IN NORTH CENTRAL KANSAS. AFTERNOON HEAT INDICES IN THE 98 TO 104 DEGREE RANGE ARE EXPECTED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 343 PM CDT TUE JUN 25 2013 THE LLVL FLOW VEERS AROUND TO THE SOUTHEAST THEN SOUTH TO SOUTHWEST WEDNESDAY NIGHT INTO THURSDAY...WARMER AIR AND DEEPER MOISTURE WILL ADVECT BACK INTO THE COUNTY WARNING AREA. A STRONG 850MB THERMAL AXIS WILL PUSH WARMER TEMPS NORTHEAST INTO THE CWA...ESPECIALLY THE SOUTHWEST COUNTIES WHERE HIGHS IN THE 100-103 RANGE SHOULD BE COMMON AS MIXING ACROSS THE AREA BY AFTERNOON DEEPENS SUBSTANTIALLY. THIS WILL NOT ONLY RAISE TEMPS...BUT AT THE SAME TIME...LOWER DEWPOINTS...MAINLY OVER THE WESTERN COUNTIES. HEAT INDICES THURSDAY WILL COMMONLY BE IN THE 100-105 RANGE. A SUBSTANTIAL EML WILL BE IN PLACE TO THE START THE AFTERNOON...BUT BY LATE IN THE DAY OVER THE NORTHERN COUNTIES...IT WILL LIKELY ERODE WITH ISOLATED THUNDERSTORMS POSSIBLE AND WILL CARRY A SLIGHT CHANCE POP. ALTHOUGH WINDS ALOFT WILL NOT BE ESPECIALLY STRONG...AN AREA OF HIGH CAPE VALUES AND INCREASING DIRECTIONAL SHEAR THROUGH 6KM WILL DEVELOP ALONG AND AHEAD OF THE BOUNDARY SLIPPING SOUTHWARD LATE IN THE DAY AND EVENING. WOULD EXPECT SOME INCREASE IN COVERAGE OF ANY LATE AFTERNOON CONVECTION. ALTHOUGH HAIL IS POSSIBLE...A DEEP LAYER OF NEARLY ADIABATIC LAPSE RATES COULD MAKE STRONG WINDS GUSTS THE PRIMARY HAZARD FOR ANY CONVECTION THAT MAY DEVELOPS. MODELS SEEM A FAIRLY GOOD AGREEMENT THAT ANY CONVECTION THAT DEVELOPS...SHOULD BE SOUTH OF THE CWA BY SUNRISE FRIDAY AS THE BOUNDARY MOVES SOUTHWARD. WILL KEEP THE HIGHEST POPS OVER THE FAR NORTHEAST/EASTERN COUNTIES. IT SHOULD ALSO MARK THE BEGINNING OF A GRADUAL DECLINE IN BOTH TEMPERATURES AND DEWPOINTS AS A LARGE SCALE UPPER TROUGH DEEPENS THROUGH THE WEEKEND OVER THE EASTERN CONUS. DEWPOINTS WILL COMMONLY BE IN THE 50S TO NEAR 60 DEGREES THROUGH THE WEEKEND. ALTHOUGH IT WILL STILL BE THE LOW TO MIDDLE 90S MOST AREAS FRIDAY...HIGHS IN THE 80S WILL BE THE RULE THROUGH THE WEEKEND INTO EARLY NEXT WEEK. WILL CARRY A SLIGHT CHANCE FOR THUNDERSTORMS OVER THE FAR NORTHEAST ON SUNDAY. ALTHOUGH CANNOT TOTALLY RULE OUT ISOLATED CONVECTION IN THE NORTHWEST FLOW REGIME OVER THE AREA...DRIER AIR OVER THE AREA AND THE LACK OF ANY CONSISTENT FORCING MECHANISM TO DEVELOP PRECIP WARRANTS KEEPING THE REMAINDER OF THE FCST DRY AT THIS POINT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1122 PM CDT TUE JUN 25 2013 WITH WATER VAPOR SHOWING AN UPPER LEVEL TROUGH PASSING EAST OF THE MO RIVER AND THE DIURNALLY DRIVEN CONVECTION IN SOUTH CENTRAL KS DISSIPATING...THINK VFR CONDITIONS WILL PREVAIL OVERNIGHT. BOTH THE NAM AND RAP SHOW THE BEST COMBINATION OF ISENTROPIC UPGLIDE AND SATURATION TO REMAIN OVER NORTHERN MO AND MOVING TO THE EAST OVERNIGHT. WITH NEW ELEVATED STORMS ALREADY EAST OF THE MO RIVER...IT IS HARD TO SEE ANYTHING FORMING IN KS. WINDS SHOULD GRADUALLY DIMINISH OVERNIGHT AS THE SFC LOW CONTINUES TO FILL AND THE PRESSURE GRADIENT WEAKENS. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WOLTERS SHORT TERM...53 LONG TERM...63 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
731 AM EDT WED JUN 26 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 338 AM EDT WED JUN 26 2013 A SHORTWAVE CURRENTLY OVER THE DAKOTAS IS PRODUCING A LINE OF THUNDERSTORMS ALONG THE SD/MN AND ND/MN BORDERS. THUNDERSTORMS ACTIVITY HAS BEEN WANING OVER THE LAST COUPLE OF HOURS...BUT WIDESPREAD PRECIP IS STILL OCCURRING. THIS SHORTWAVE WILL MOVE OVER THE CWA THROUGH THE END OF THE SHORT TERM /12 THU/. CONTINUED TO SHOW POPS ALONG AND AHEAD OF THE SHORTWAVE GIVEN EXTENT OF CURRENT ACTIVITY. THERE IS AN OUTSIDE CHANCE AT A STRONGER STORM OR TWO TODAY...WITH SOME STRONGER WINDS AND SMALL HAIL...GIVEN AROUND 1000J/KG OF CAPE...WEAK SHEAR AND A GOOD AMOUNT OF DRY AIR IN FORECAST SOUNDINGS. EXPECT HIGHS FROM THE UPPER 60S RIGHT ALONG LAKE SUPERIOR TO THE MID 80S INTERIOR. TONIGHT EXPECT LOWS IN THE 50S AND 60S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 338 AM EDT WED JUN 26 2013 NAM SHOWS A 500 MB RIDGE OVER THE ROCKIES WITH TROUGHING IN THE EASTERN U.S. 12Z THU. THE 500 MB RIDGE AMPLIFIES THIS PERIOD WITH TROUGHING DIGGING IN THE EASTERN HALF OF THE U.S. NAM KEEPS SOME 850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA 12Z THU ONWARD THROUGH THE REST OF THIS FORECAST PERIOD WITH SOME MOISTURE AROUND. WILL CONTINUE WITH THE SLIGHT CHANCE TO CHANCE POPS FOR THIS PERIOD. DOES NOT LOOK LIKE A TOTAL WASHOUT AND CONVECTION WILL BE SCATTERED AT BEST. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT DID WARM TEMPERATURES UP A BIT ON THU AS 850 MB TEMPERATURES OF 16C MIXED DOWN TO THE SFC GIVES ME HIGH IN THE LOWER TO MID 80S. COLDER AIR ARRIVES FOR FRI THEN. IN THE EXTENDED...A STRONG 500 MB RIDGE SETS UP IN THE ROCKIES LEADING TO A HEAT WAVE IN THE WESTERN U.S. 12Z SAT WHILE A DEEP 500 MB TROUGH DIGS INTO THE EASTERN U.S. THE 500 MB PATTERN CHANGES VERY LITTLE IN THE EXTENDED WITH THE TROUGH REMAINING OVER THE UPPER GREAT LAKES REGION THROUGH TUE WITH PATTERN AMPLIFICATION. WHAT THIS MEANS IS HEAT IN THE WESTERN U.S. AND COLDER THAN NORMAL TEMPERATURES OVER THE AREA FOR AN EXTENDED PERIOD OF TIME. AFTER SAT...LOOKS DRY FOR THE EXTENDED PERIOD EVEN WITH TROUGHING OVERHEAD AND SFC RIDGING. WILL GO DRY SAT NIGHT ONWARD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 730 AM EDT WED JUN 26 2013 THERE IS SOME LIGHT MORNING FOG AT SAW /AND OCCASIONALLY AT IWD/...BUT THIS FOG SHOULD BURN OFF QUICKLY. OTHERWISE...EXPECT VFR CONDITIONS THROUGH AT LEAST MID AFTN. APPROACHING DISTURBANCE SHOULD BRING SHRA/SCT TSRA INTO UPPER MI LATER THIS AFTN. INCLUDED SHRA/VCTS AND MVFR CONDITIONS AT KIWD/KCMX LATE AFTN/EARLY EVENING AND AT KSAW MID TO LATE EVENING. SHRA/SCT TSRA SHOULD BE IN THE AREA FOR SEVERAL HRS. PROVIDED RAIN DOES OCCUR AT KCMX...CONDITIONS MAY FALL TO IFR OR LWR ONCE PCPN ENDS THIS EVENING AS WINDS SHOULD HAVE SOME UPSLOPE COMPONENT OFF THE LAKE. FOLLOWED HRRR MORE CLOSELY FOR PRECIP TIMING THIS AFTERNOON/EVENING AS IT HAS BEEN PERFORMING FAIRLY WELL WITH CONVECTION. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 338 AM EDT WED JUN 26 2013 OVERALL...WINDS ARE EXPECTED TO BE BELOW 20KTS THROUGH THE PERIOD AS THE PRESSURE PATTERN REMAINS FAIRLY WEAK ACROSS THE AREA. WITH THE WARM MOIST AIR OVER THE UPPER GREAT LAKES...WILL CONTINUE TO MENTION PATCHY/AREAS OF FOG THROUGH TONIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...TITUS LONG TERM...07 AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
156 AM EDT WED JUN 26 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 430 PM EDT TUE JUN 25 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A LOW AMPLITUDE PATTERN WITH A TROUGH INTO THE PAC NW AND A RIDGE FROM THE UPPER MS VALLEY INTO MANITOBA. THE MAIN UPSTREAM SHORTWAVE TROUGH EXTENDED FROM ERN MONTANA INTO WRN SD. AT THE SFC...A WEAK RIDGE AND LIGHT PRES GRADIENT PREVAILED OVER THE THE REGION ALLOWING PROMINENT LAKE BREEZES TO DEVELOP. CAPPING HAS BEEN STRONG ENOUGH TO SUPPRESS CONVECTION THROUGH 20Z DESPITE LOW LEVEL CONV...INLAND MLCAPE VALUES TO NEAR 1500 J/KG AND CU/TCU LINE DEVELOPMENT. MIXING HAS ALSO BEEN STRONG ENOUGH TO DROP DEWPOINTS INTO THE MID AND UPPER 50S NEAR THE WI BORDER TONIGHT...POTENTIAL REMAINS FOR SOME ISOLD SHRA/TSRA DEVELOPMENT...MAINLY OVER THE SOUTH NEAR THE LAKE BREEZE BOUNDARIES. WITH THE LOSS OF DAYTIME HEATING...ANY PCPN CHANCES WILL ALSO DIMINISH THIS EVENING. EVEN WITH FAVORABLE RADIATIONAL COOLING OVERNIGHT...ENOUGH LOW LEVEL MOISTURE REMAINS TO KEEP MIN TEMPS FROM DROPPING MUCH BELOW 60F. SOME PATCHY FOG MAY ALSO DEVELOP. WED...THE NRN PLAINS SHRTWV AND ASSOCIATED SFC TROUGH MOVING INTO THE WRN LAKES WILL BE THE FOCUS FOR SHRA/TSRA DEVELOPMENT. THE MODELS WERE IN RELATIVELY GOOD AGREEMENT BRINGING THE HIGHER PCPN CHANCES INTO THE WEST HALF OF THE CWA DURING THE AFTERNOON. THE AIRMASS OVER REGION SHOULD AGAIN ALLOW TEMPS TO CLIMB INTO THE LOWER 80S INLAND AND BEFORE LAKE BREEZES TAKE OVER. MLCAPE VALUES MAY AGAIN CLIMB TO AROUND 1500 J/KG BUT RELATIVELY MODEST SHEAR VALUES WILL LIMIT STRONG/SEVERE STORM POTENTIAL. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 430 PM EDT TUE JUN 25 2013 OVERALL PATTERN WILL EVOLVE INTO AN AMPLIFIED ONE FOR LATE JUNE STANDARDS DURING THE LATE WEEK PERIOD WITH INTENSE UPPER RIDGING DEVELOPING OVER THE WESTERN U.S. AND TROUGHING DEVELOPING OVER THE GREAT LAKES AND EASTERN U.S. AS HAS BEEN THE CASE OVER THE LAST SEVERAL DAYS TIMING OF A BETTER PRECIP CHANCES DURING THE NEXT COUPLE OF DAYS WILL REMAIN A CHALLENGE. CONFIDENCE IS PRETTY HIGH THAT ALL AREAS WILL SEE AT LEAST SOME RAINFALL BETWEEN THE WEDNESDAY NIGHT THROUGH SATURDAY TIME PERIOD. HOWEVER...MORE OF THAT TIME WILL BE DRY RATHER THAN RAINY. WHILE SCATTERED POPS SEEM THE WAY TO GO FOR THIS TIME PERIOD...WILL GO WITH SLIGHTLY HIGHER POPS DURING THE WED NIGHT TIME PERIOD AS SHORTWAVE ENERGY BEGINS TO CARVE OUT UPPER TROUGHING OVER THE GREAT LAKES. WILL ALSO GO ON THE HIGHER END OF CHANCE POPS FOR FRIDAY INTO SATURDAY AS MAIN TROUGH AXIS MOVES THROUGH THE AREA. A SCATTERING OF POPS DURING THE OTHER PERIODS SEEMS REASONABLE. WITH LIMITED INSTABILITY AND SHEAR EXPECTED...THUNDER CHANCES WILL BE MORE IN THE ISOLATED TO SLIGHT CHANCE RANGE. HIGH PRESSURE AND DRIER AIR SHOULD BEGIN PUSHING INTO THE AREA FROM THE NORTH BY LATE IN THE DAY SATURDAY ENDING THE RAIN CHANCES. UPPER TOUGHING WILL REMAIN OVER THE AREA INTO EARLY NEXT WEEK KEEPING TEMPERATURES AT TO JUST SLIGHTLY BELOW NORMAL THROUGH THE WEEKEND INTO MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 155 AM EDT WED JUN 26 2013 THERE MAY BE SOME RADIATIONAL FOG (MVFR VIS) OVERNIGHT AT KIWD/KSAW AND PERHAPS KCMX. OTHERWISE...EXPECT VFR CONDITIONS THRU AT LEAST MID AFTN. APPROACHING DISTURBANCE SHOULD BRING SHRA/SCT TSRA INTO UPPER MI LATER THIS AFTN. INCLUDED SHRA/VCTS AND MVFR CONDITIONS AT KIWD/KCMX LATE AFTN/EARLY EVENING AND AT KSAW MID TO LATE EVENING. SHRA/SCT TSRA SHOULD BE IN THE AREA FOR SEVERAL HRS. PROVIDED RAIN DOES OCCUR AT KCMX...CONDITIONS MAY FALL TO IFR OR LWR ONCE PCPN ENDS THIS EVENING AS WINDS SHOULD HAVE SOME UPSLOPE COMPONENT OFF THE LAKE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 430 PM EDT TUE JUN 25 2013 OVERALL...WINDS ARE EXPECTED TO BE BELOW 20KTS THROUGH THE PERIOD AS THE PRESSURE PATTERN REMAINS FAIRLY WEAK ACROSS THE AREA. WITH THE WARM MOIST AIR OVER THE UPPER GREAT LAKES...WILL CONTINUE TO MENTION PATCHY/AREAS OF FOG THROUGH WEDNESDAY NIGHT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MZ AVIATION...ROLFSON MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
103 PM CDT WED JUN 26 2013 .AVIATION... THUNDERSTORMS...CONTAINING HEAVY RAINFALL...WILL ACCOMPANY A FRONTAL BOUNDARY AS IT CROSSES OVER THE MINNESOTA ARROWHEAD AND NORTHERN WISCONSIN THIS AFTERNOON. THE STRONGEST STORMS...LASTING ABOUT AN HOUR...WILL BE FOUND IN THE HAYWARD AREA BETWEEN 19Z-21Z THIS AFTERNOON. A FEW ADDITIONAL SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE THOUGH THE AFTERNOON ACROSS NORTHEAST MINNESOTA WHERE PERIODS OF MVFR CEILINGS AROUND 2 KFT WILL PERSIST. HAVE KEPT VCTS/VCSH AT ALL MINNESOTA TERMINALS FOR THE REMAINDER OF THE DAY WITH IMPROVING CEILINGS THROUGH THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 1045 AM CDT WED JUN 26 2013/ UPDATE... THE FOCUS FOR THIS UPDATE IS THE POTENTIAL OF SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING. THE ONLY REMAINING SHOWERS AND STORMS AT THE TIME OF THIS UPDATE ARE NEAR A VORTEX MOVING NORTHEAST NEAR IN NORTHERN ST. LOUIS COUNTY. REDEVELOPMENT ALONG AND AHEAD OF TROUGH OF LOW PRESSURE MOVING THROUGH THE NORTHLAND TODAY IS LIKELY...AT LEAST IN NW WISCONSIN AND THE MINNESOTA ARROWHEAD. THE HRRR HAS BEEN CONSISTENTLY INDICATING A BAND OF STORMS FORMING IN NW WISCONSIN BY EARLY THIS AFTERNOON AND EXITING MID TO LATE THIS AFTERNOON. I ALTERED PCPN CHANCES TO REFLECT THE HIGHEST CHANCES ACROSS THE EASTERN FORECAST AREA...WHILE LOWERED CHANCES ACROSS THE WEST. WHILE THERE SHOULD BE A GENERAL DECREASING CHANCE OF PCPN FROM WEST TO EAST THIS AFTERNOON INTO THIS EVENING...SOME MODELS ARE INDICATING SOME SHOWERS AND STORMS MOVING INTO THE WESTERN FORECAST AREA FROM NW MINNESOTA THIS EVENING AND OVERNIGHT...SO I KEPT LOW CHANCES OVER JUST ABOUT ALL OF THE FORECAST AREA THROUGH AT LEAST THIS EVENING. IT STILL APPEARS WE COULD SEE SOME STRONG...MAYBE SEVERE STORMS...ACROSS NW WISCONSIN. WHILE THERE MAY BE LOTS OF CAPE...WITH THE NAM12 INDICATING AT LEAST 4000 J/KG OF MOST UNSTABLE CAPE ALONG THE CAPE AXIS...THE LIMITING FACTOR FOR SEVERE WEATHER WILL LIKELY BE WIND SHEAR. THE NAM12 IS INDICATING LOW BULK SHEAR...LESS THAN 20 KNOTS FOR 0-6KM...ALONG THE CAPE AXIS. HOWEVER...WE WILL NEED TO WATCH CLOSELY FOR DEVELOPMENT AND SEE IF THE NAM12 WIND SHEAR HOLDS TRUE. IF THERE IS MORE WIND SHEAR THAN THE NAM12 SUGGESTS...THEN SOME STORMS COULD MORE EASILY BECOME SEVERE. AS FAR AS TEMPERATURES TODAY...THE LATEST MOS GUIDANCE IS MUCH WARMER IN SOME AREAS COMPARED TO THE PREVIOUS FORECAST. I INCREASED TEMPERATURES BY UP TO SEVERAL DEGREES...NOTABLE ACROSS INLAND NW WISCONSIN. PREV DISCUSSION... /ISSUED 316 AM CDT WED JUN 26 2013/ SHORT TERM...SHORT TERM CONCERNS IS MOVEMENT OF THUNDERSTORM COMPLEX IN NW MN THIS MORNING AND EFFECT ON FORECAST AREA. SECOND CONCERN IS TSTM CHANCES. CURRENT SURFACE ANALYSIS INDICATES AREA OF THUNDERSTORMS ACROSS NW MN MOVING EAST-NORTHEAST. CAPES RANGE FROM 2500-4000 WITH THE STORMS WITH THE STRONGEST STORMS JUST EAST OF FARGO. SHEAR IS WEAKER TOWARD THE WESTERN AREAS OF THE FORECAST AREA BUT CAPES ARE STILL ON THE HIGH SIDE ALONG WITH PLENTY OF MOISTURE. THE PRECIP AREA HAS STARTED TO CLIP NW KOOCHCHING COUNTY AND WILL SPREAD EAST EARLY THIS MORNING. THE PRECIP WILL DECREASE IN INTENSITY AND COVERAGE AS IT MOVES THROUGH NE MN. THE NEXT CONCERN FOR THE SHORT TERM IS THUNDERSTORM DEVELOPMENT THIS AFTERNOON. THERE WILL BE SOME DEBRIS CLOUDS LEFT OVER FROM THIS MORNING`S STORMS ACROSS NW MN. THE QUESTION FOR THE FORECAST IS HOW MUCH SUN WILL BE SEEN LATE THIS MORNING AND THIS AFTERNOON. BASED ON CURRENT TRENDS...THERE COULD BE SOME SUN THIS AFTERNOON ACROSS EASTERN PORTIONS OF NE MN AND ALL NW WI. THIS WILL INCREASE THE INSTABILITY THIS AFTERNOON OVER THAT REGION SO WILL KEEP CURRENT POPS FOR TSTMS. SPC HAS THE SOUTHERN TIER OF NW WI COUNTIES IN A SLIGHT RISK AREA FOR THIS AFTERNOON AND TONIGHT. WEAK HIGH PRESSURE WILL BUILD INTO THE WESTERN PORTION OF MN AREA TONIGHT ENDING THE PRECIP TONIGHT AND WEDNESDAY. THE ONLY EXCEPTION WILL BE OVER THE ARROWHEAD WHERE THE TROUGH WILL KEEP THE POSSIBILITY OF THUNDERSTORMS ACROSS THAT REGION THROUGH THURSDAY. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY THURSDAY NIGHT AND FRIDAY WE WILL HAVE A STATIONARY FRONT DRAPED ACROSS THE ARROWHEAD REGION. THIS WILL BE ASSOCIATED WITH SOME CHANNELED VORT MAXES IN THE STRONG NORTHWEST FLOW OVER THE REGION...ON THE BACK SIDE OF THE UPPER LEVEL TROUGH OVER THE EAST COAST AND THE STRONG RIDGE OVER THE ROCKIES. THIS WARRANTS SOME HIGH CHANCE TO LOW END LIKELY POPS OVER THE ARROWHEAD REGION THURSDAY NIGHT AND FRIDAY...ALONG WITH COOLER FRIDAY HIGHS IN THE LOW 70S. ELSEWHERE HIGHS SHOULD RISE INTO THE MID TO UPPER 70S. FRIDAY NIGHT AND SATURDAY THE FRONT IS PUSHED SOUTH AS A COLD FRONT ALONG WITH A MORE VIGOROUS SHORTWAVE THAT DIGS DOWN ACROSS MN AND WI. THIS SHIFTS OUR POPS SOUTH ACROSS THE REGION...HAVE HAVE PUT MAINLY CHANCE POPS THROUGH THE PERIOD. SATURDAY LOOKS COOLER WITH HIGHS ONLY IN THE LOW TO MID 70S...DEPENDING ON HOW MUCH SUNSHINE CAN GET THROUGH. SATURDAY NIGHT THROUGH SUNDAY AND INTO MONDAY WE MOVE INTO A DRY PERIOD AS THE SHORTWAVE THAT MOVED THROUGH ON SATURDAY DIGS SOUTH AND LEAVES US WITH SOME RIDGING ALOFT AND WEAK RIDGING AT THE SURFACE AS WELL. THE SHORTWAVE EVENTUALLY CUTS OFF OVER THE DEEP SOUTH STATES...AND TOGETHER WITH THE RIDGE OUT WEST REALLY SLOWS DOWN OUR UPPER LEVEL PATTERN. THUS...WHILE I DO HAVE SOME SMALL CHANCE POPS OUT FOR LATER MONDAY THROUGH TUESDAY...THEY ARE PRETTY MINOR AND CONFIDENCE IS NOT TERRIBLY HIGH. HIGHS SHOULD RISE UP INTO THE UPPER 70S TO NEAR 80. && .POINT TEMPS/POPS... DLH 59 80 57 75 / 30 40 10 40 INL 60 79 58 75 / 30 40 20 40 BRD 62 81 60 79 / 20 10 10 20 HYR 61 80 57 77 / 40 40 10 40 ASX 56 76 56 72 / 50 30 20 70 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS DULUTH MN
1045 AM CDT WED JUN 26 2013 .UPDATE... THE FOCUS FOR THIS UPDATE IS THE POTENTIAL OF SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING. THE ONLY REMAINING SHOWERS AND STORMS AT THE TIME OF THIS UPDATE ARE NEAR A VORTEX MOVING NORTHEAST NEAR IN NORTHERN ST. LOUIS COUNTY. REDEVELOPMENT ALONG AND AHEAD OF TROUGH OF LOW PRESSURE MOVING THROUGH THE NORTHLAND TODAY IS LIKELY...AT LEAST IN NW WISCONSIN AND THE MINNESOTA ARROWHEAD. THE HRRR HAS BEEN CONSISTENTLY INDICATING A BAND OF STORMS FORMING IN NW WISCONSIN BY EARLY THIS AFTERNOON AND EXITING MID TO LATE THIS AFTERNOON. I ALTERED PCPN CHANCES TO REFLECT THE HIGHEST CHANCES ACROSS THE EASTERN FORECAST AREA...WHILE LOWERED CHANCES ACROSS THE WEST. WHILE THERE SHOULD BE A GENERAL DECREASING CHANCE OF PCPN FROM WEST TO EAST THIS AFTERNOON INTO THIS EVENING...SOME MODELS ARE INDICATING SOME SHOWERS AND STORMS MOVING INTO THE WESTERN FORECAST AREA FROM NW MINNESOTA THIS EVENING AND OVERNIGHT...SO I KEPT LOW CHANCES OVER JUST ABOUT ALL OF THE FORECAST AREA THROUGH AT LEAST THIS EVENING. IT STILL APPEARS WE COULD SEE SOME STRONG...MAYBE SEVERE STORMS...ACROSS NW WISCONSIN. WHILE THERE MAY BE LOTS OF CAPE...WITH THE NAM12 INDICATING AT LEAST 4000 J/KG OF MOST UNSTABLE CAPE ALONG THE CAPE AXIS...THE LIMITING FACTOR FOR SEVERE WEATHER WILL LIKELY BE WIND SHEAR. THE NAM12 IS INDICATING LOW BULK SHEAR...LESS THAN 20 KNOTS FOR 0-6KM...ALONG THE CAPE AXIS. HOWEVER...WE WILL NEED TO WATCH CLOSELY FOR DEVELOPMENT AND SEE IF THE NAM12 WIND SHEAR HOLDS TRUE. IF THERE IS MORE WIND SHEAR THAN THE NAM12 SUGGESTS...THEN SOME STORMS COULD MORE EASILY BECOME SEVERE. AS FAR AS TEMPERATURES TODAY...THE LATEST MOS GUIDANCE IS MUCH WARMER IN SOME AREAS COMPARED TO THE PREVIOUS FORECAST. I INCREASED TEMPERATURES BY UP TO SEVERAL DEGREES...NOTABLE ACROSS INLAND NW WISCONSIN. && .PREV DISCUSSION... /ISSUED 659 AM CDT WED JUN 26 2013/ AVIATION... BAND OF WEAKENING CONVECTION CURRENTLY SWEEPING ACROSS THE TERMINALS THIS MORNING. LINGERING STORMS BRINGING IFR TO MVFR CIGS AND VSBYS AT THEY MOVE THROUGH EACH LOCATION. KHYR...WHICH HAS BEEN IN THE CLEAR ALL NIGHT HAS DEVELOPED SOME MVFR FOG WHICH SHOULD CLEAR BY 13Z. KDLH ALSO DEVELOPED SOME EARLY MORNING FOG...WHICH SHOULD ALSO CLEAR IN NEXT COUPLE HOURS. ADDITIONAL THUNDERSTORM DEVELOPMENT IS EXPECTED THIS AFTERNOON...MAINLY FOR KINL...KHIB...KDLH AND KHYR. TIMING AND LOCATIONS UNCERTAIN SO HAVE GONE WITH ONLY VCTS FOR NOW...BUT WILL HAVE TO REFINE WITH LATER ISSUANCES. BY LATE AFTERNOON WEAK COLD FRONT TO MOVE THROUGH THE AREA AND TURN WINDS TO WEST...ALSO ENDING TSRA CHANCES. LE PREV DISCUSSION... /ISSUED 316 AM CDT WED JUN 26 2013/ SHORT TERM...SHORT TERM CONCERNS IS MOVEMENT OF THUNDERSTORM COMPLEX IN NW MN THIS MORNING AND EFFECT ON FORECAST AREA. SECOND CONCERN IS TSTM CHANCES. CURRENT SURFACE ANALYSIS INDICATES AREA OF THUNDERSTORMS ACROSS NW MN MOVING EAST-NORTHEAST. CAPES RANGE FROM 2500-4000 WITH THE STORMS WITH THE STRONGEST STORMS JUST EAST OF FARGO. SHEAR IS WEAKER TOWARD THE WESTERN AREAS OF THE FORECAST AREA BUT CAPES ARE STILL ON THE HIGH SIDE ALONG WITH PLENTY OF MOISTURE. THE PRECIP AREA HAS STARTED TO CLIP NW KOOCHCHING COUNTY AND WILL SPREAD EAST EARLY THIS MORNING. THE PRECIP WILL DECREASE IN INTENSITY AND COVERAGE AS IT MOVES THROUGH NE MN. THE NEXT CONCERN FOR THE SHORT TERM IS THUNDERSTORM DEVELOPMENT THIS AFTERNOON. THERE WILL BE SOME DEBRIS CLOUDS LEFT OVER FROM THIS MORNING`S STORMS ACROSS NW MN. THE QUESTION FOR THE FORECAST IS HOW MUCH SUN WILL BE SEEN LATE THIS MORNING AND THIS AFTERNOON. BASED ON CURRENT TRENDS...THERE COULD BE SOME SUN THIS AFTERNOON ACROSS EASTERN PORTIONS OF NE MN AND ALL NW WI. THIS WILL INCREASE THE INSTABILITY THIS AFTERNOON OVER THAT REGION SO WILL KEEP CURRENT POPS FOR TSTMS. SPC HAS THE SOUTHERN TIER OF NW WI COUNTIES IN A SLIGHT RISK AREA FOR THIS AFTERNOON AND TONIGHT. WEAK HIGH PRESSURE WILL BUILD INTO THE WESTERN PORTION OF MN AREA TONIGHT ENDING THE PRECIP TONIGHT AND WEDNESDAY. THE ONLY EXCEPTION WILL BE OVER THE ARROWHEAD WHERE THE TROUGH WILL KEEP THE POSSIBILITY OF THUNDERSTORMS ACROSS THAT REGION THROUGH THURSDAY. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY THURSDAY NIGHT AND FRIDAY WE WILL HAVE A STATIONARY FRONT DRAPED ACROSS THE ARROWHEAD REGION. THIS WILL BE ASSOCIATED WITH SOME CHANNELED VORT MAXES IN THE STRONG NORTHWEST FLOW OVER THE REGION...ON THE BACK SIDE OF THE UPPER LEVEL TROUGH OVER THE EAST COAST AND THE STRONG RIDGE OVER THE ROCKIES. THIS WARRANTS SOME HIGH CHANCE TO LOW END LIKELY POPS OVER THE ARROWHEAD REGION THURSDAY NIGHT AND FRIDAY...ALONG WITH COOLER FRIDAY HIGHS IN THE LOW 70S. ELSEWHERE HIGHS SHOULD RISE INTO THE MID TO UPPER 70S. FRIDAY NIGHT AND SATURDAY THE FRONT IS PUSHED SOUTH AS A COLD FRONT ALONG WITH A MORE VIGOROUS SHORTWAVE THAT DIGS DOWN ACROSS MN AND WI. THIS SHIFTS OUR POPS SOUTH ACROSS THE REGION...HAVE HAVE PUT MAINLY CHANCE POPS THROUGH THE PERIOD. SATURDAY LOOKS COOLER WITH HIGHS ONLY IN THE LOW TO MID 70S...DEPENDING ON HOW MUCH SUNSHINE CAN GET THROUGH. SATURDAY NIGHT THROUGH SUNDAY AND INTO MONDAY WE MOVE INTO A DRY PERIOD AS THE SHORTWAVE THAT MOVED THROUGH ON SATURDAY DIGS SOUTH AND LEAVES US WITH SOME RIDGING ALOFT AND WEAK RIDGING AT THE SURFACE AS WELL. THE SHORTWAVE EVENTUALLY CUTS OFF OVER THE DEEP SOUTH STATES...AND TOGETHER WITH THE RIDGE OUT WEST REALLY SLOWS DOWN OUR UPPER LEVEL PATTERN. THUS...WHILE I DO HAVE SOME SMALL CHANCE POPS OUT FOR LATER MONDAY THROUGH TUESDAY...THEY ARE PRETTY MINOR AND CONFIDENCE IS NOT TERRIBLY HIGH. HIGHS SHOULD RISE UP INTO THE UPPER 70S TO NEAR 80. && .POINT TEMPS/POPS... DLH 80 59 80 57 / 50 30 40 10 INL 82 60 79 58 / 70 30 40 20 BRD 86 62 81 60 / 30 20 10 10 HYR 86 61 80 57 / 60 40 40 10 ASX 84 56 76 56 / 50 50 30 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS DULUTH MN
1231 AM CDT WED JUN 26 2013 .AVIATION...06Z TAF ISSUANCE... EARLY MORNING BR/FG EXPECTED AT KHYR/KDLH/KHIB WITH POTENTIAL FOR CEILINGS TO LOWER TO IFR/LIFR. NOT AS CONFIDENT ON FG/BR AT KHIB HOWEVER CLIMO FAVORS AT LEAST A TEMPO IFR VIS. OTHERWISE MAIN FEATURE WILL BE AREAL COVERAGE/TIMING OF CONVECTION WITH APPROACHING FRONTAL SYSTEM. MDLS STILL VARY ON TIMING OF MAIN AXIS OF MOISTURE/LIFT SO HAVE MAINTAINED THE PROB30 WORDING FOR ALL SITES. APPEARS THAT A 6HR WINDOW OF OPPORTUNITY WILL EXIST BEFORE FROPA/WINDSHIFT TO SW AND WEST OCCURS LATER IN THE AFTN...EXCEPT AT KHYR WHERE FROPA WILL BE LATER. && .PREV DISCUSSION... /ISSUED 1100 PM CDT TUE JUN 25 2013/ UPDATE...ADDED PATCHY FOG TO WISCONSIN ZONES AND NEAR TWIN PORTS AFTER 08Z PER SFC T/TD SPREADS AT THIS HOUR. LATEST HRRR 3KM FCST OF LOWERING VISIBILITY ALSO SUPPORTS THIS IDEA ALONG WITH PERSISTENCE FROM PREVIOUS NIGHTS ALTHOUGH EVENTUALLY MORE HIGH LVL CLOUD COVER WILL WORK ITS WAY IN FROM THE WEST. CONVECTIVE COMPLEXES CONTINUE NEAR SFC LOW/TROF OVER ERN NODAK/MN BORDER IN AN AREA OF MAXIMUM 85H MSTR TRANSPORT AND WELL DEFINED 85/30H THICKNESS DIFFLUENCE. 03Z HRRR SIM REFL BRINGS REMNANTS OF THIS AREA INTO NWRN CWA AFTER 08Z WITH A SECONDARY LINE MOVING INTO WRN/SWRN CWA AROUND 15Z. NSSL WRF MAKES MORE OF A CASE FOR CONVECTION TO MAINTAIN SOME ORGANIZATION AS IT MOVES INTO CWA AND HEADS TOWARDS TWIN PORTS AROUND 12Z. USING PROGRESSION OF MID LVL SHEAR AXIS PUTS HIGHEST POPS OVER ERN CWA WED AFTN. INCREASED POPS IN THIS AREA. ALSO RAISED MAX TEMPS FROM TWIN PORTS WEST AS IT APPEARS THAT PROGRESSION OF WESTERLY FLOW IN MIXING LAYER MAY ALLOW SOME LATE DAY WARMING. PREV DISCUSSION... /ISSUED 703 PM CDT TUE JUN 25 2013/ UPDATE...UPDATE TO DELAY ARRIVAL OF POPS A FEW HRS AS MAIN FOCUS OF ACTIVITY IS OCCURRING WITHIN 85H THETAE AXIS ASSOCIATED WITH SFC LOW/TROF OVER CENTRAL DAKOTAS. AS STATED IN PRIOR DISCUSSION ATMOSPHERE IS QUITE UNSTABLE OVER CWA. WITH BDRY LYR DECOUPLING...SPC MESO SHOWS AREAL COVERAGE OF SBCIN INCREASING. BOTH NSSL WRF-ARW AND SPC WRF-NMM SIM REFLECTIVITY PRODUCTS DEPICT CURRENT SITUATION DECENTLY REGARDING NODAK LINE OF CONVECTION. FCST INDICATES CONSIDERABLE WEAKENING OF THE LINE AFTER IT CROSSES NODAK/MN STATE LINE AND ENTERS WRN CWA BY 09Z. WILL MONITOR ACTIVITY TO THE WEST THIS EVENING AND AMEND ACCORDINGLY. PREV DISCUSSION... /ISSUED 649 PM CDT TUE JUN 25 2013/ AVIATION...00Z TAF ISSUANCE... VFR CONDITIONS ACROSS NE MINNESOTA AND NW WISCONSIN WILL CONTINUE THIS EVENING. BR AND/OR FG IS POSSIBLE LATE TONIGHT AND EARLY WEDNESDAY MORNING. THE MOST LIKELY LOCATIONS FOR FG ARE KDLH AND KHYR. STORMS IN THE NORTHERN PLAINS WILL APPROACH THE WRN CWA AFTER MIDNIGHT. MOST LIKELY TIME FOR RW/TRW AT KINL/KBRD WOULD BE LATE MORNING/EARLY AFTN...WITH AFTN HRS MORE LIKELY NEAR KHIB/KDLH/KHYR. WILL TRY TO NARROW WINDOW IN NEXT FCST AT 06Z. PREV DISCUSSION... /ISSUED 315 PM CDT TUE JUN 25 2013/ SHORT TERM...TONIGHT AND WEDNESDAY... AT 300 PM VISIBLE SATELLITE IMAGERY DEPICTED MOSTLY SUNNY TO PARTLY CLOUDY SKIES ACROSS THE NORTHLAND. TEMPERATURES RANGED FROM 87 AT KHIB TO 85 AT KBRD...83 AT KHYR...85 AT KDLH. COOLER READINGS WERE FOUND NEAR LAKE SUPERIOR WITH 70 DEGREES AT KDYT/DULUTH HARBOR...67 LAKESIDE AT SILVER BAY AND A CHILLY 50 DEGREES AT GRAND MARAIS. THE FORECAST AREA WILL REMAIN SITUATED BETWEEN A H85 LOW/SFC TROUGH APPROACHING FROM THE DAKOTAS...AND A WARM FRONT LIFTING INTO NORTHERN WISCONSIN OVERNIGHT. ALTHOUGH INSTABILITY IS HIGH...LATEST MODEL RUNS ARE IN AGREEMENT THAT THERE IS MUCH LESS CONVECTION ASSOCIATED WITH THESE BOUNDARIES AS THEY PASS OVER THE REGION THROUGH THE NEXT 24 HRS...MAINLY DUE TO THE LACK OF MID LEVEL MOISTURE. ALTHOUGH THE FRONT IS EXPECTED TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS...HAVE DECREASED POPS OVERNIGHT AND WEDNESDAY FROM PREVIOUS FORECAST DUE TO A LACK OF MID LEVEL MOISTURE TO SUPPORT WIDESPREAD ACTIVITY. HOWEVER...THE ATMOSPHERE REMAINS VERY UNSTABLE WITH SUFFICIENT CAPE TO SUPPORT STRONG TO POSSIBLY SEVERE STORMS OVERNIGHT. THE SFC BOUNDARY WILL PUSH OUT OF THE DAKOTAS LATE TONIGHT...REACH NORTH CENTRAL MINNESOTA WEDNESDAY MORNING...THEN TRACK ACROSS THE MINNESOTA ARROWHEAD AND NORTHERN WISCONSIN ZONES WEDNESDAY EVENING. AS THE FRONT PASSES...EXPECT WINDS TO SWITCH OUT OF THE NORTHWEST. GUSTS TO 20 MPH WILL BE FOUND IN THE BRAINERD LAKES AREA...MAINLY LATE IN THE DAY. TEMPERATURES WILL TOP OUT IN THE LOW 80S. HAVE PULLED BACK ON POPS TONIGHT AND WEDNESDAY TO ONLY HIGH CHANCE POPS WITH SCATTERED WORDING. HOWEVER...NAM BUFR SOUNDINGS AND RUC PROFILES SHOW SUFFICIENT CAPE TO SUPPORT STRONG TO POSSIBLY SEVERE STORMS OF THE ONES THAT WILL DEVELOP. LONG TERM [WEDNESDAY NIGHT - MONDAY] A WEAK STATIONARY FRONT WILL STRETCH FROM THE CENTRAL CANADIAN PROVINCES...OVER THE GREAT LAKES...AND INTO THE EASTERN UNITED STATES DURING THE BEGINNING OF THE PERIOD. ITS PROXIMITY AND THE NW FLOW OVER THE NORTHLAND WILL COULD HELP CAUSE PRIMARILY DAYTIME HEATING DRIVEN SHOWERS AND THUNDERSTORMS. THE NORTH AND EASTERN FORECAST AREA HAVE THE BEST CHANCE OF PCPN. THE STATIONARY FRONT SHOULD THEN SWING THROUGH THE NORTHLAND LATE THIS WEEK AS A WEAK COLD FRONT...CONTINUING THE LOW CHANCES OF SHOWERS AND THUNDERSTORMS INTO SATURDAY EVENING. THE MODELS ARE INCREASING INDICATING THAT HIGH PRESSURE WILL MOVE INTO THE UPPER MIDWEST EARLY NEXT WEEK AND LIKELY PROVIDE DRY WEATHER FOR SUNDAY AND MONDAY. TEMPERATURES SHOULD BE SLIGHTLY ABOVE NORMAL THURSDAY...NEAR NORMAL FRIDAY...SLIGHTLY BELOW NORMAL SATURDAY...AND THEN RETURNING TO NEAR NORMAL EARLY NEXT WEEK. && .POINT TEMPS/POPS... DLH 77 59 80 57 / 60 40 40 10 INL 81 60 79 57 / 70 50 40 20 BRD 84 63 83 60 / 40 20 10 10 HYR 80 60 83 58 / 50 40 40 20 ASX 77 56 80 57 / 60 50 30 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
631 PM CDT THU JUN 27 2013 ...MESOSCALE DISCUSSION AND UPDATE FOR AVIATION... .MESOSCALE DISCUSSION... ISSUED AT 630PM CDT THU JUN 27 2013 CONTINUING TO MONITOR CONVECTION EARLY THIS EVENING ACROSS CENTRAL AND EAST CENTRAL KANSAS. SEVERE LINE OF STORMS HAS DEVELOPED NORTH OF I-70 AS OF 615 PM...AND WILL CONTINUE TO RAPIDLY PUSH SOUTHEAST THIS EVENING INTO SOUTHERN KANSAS AND NORTHERN OKLAHOMA. THIS INITIAL AREA OF CONVECTION MAY CLIP A PORTION OF SOUTHEASTERN KANSAS LATER THIS EVENING IN THE 8-10 PM TIMEFRAME...BUT IN ITS CURRENT FORM...THE BULK OF THIS ACTIVITY WOULD STAY WEST OF THE SGF CWA. THAT SAID...RECENT RADAR TRENDS ARE BEGINNING TO CONFIRM THE SCENARIO DEPICTED BY SHORT TERM MODEL GUIDANCE...NAMELY RECENT RUNS OF THE HRRR AND RUC/RAP...AS NEW CONVECTION IS BEGINNING TO DEVELOP FURTHER NORTH AND EAST FROM TOPEKA TO KANSAS CITY. IF THIS CONVECTION CAN CONTINUE TO GROW UPSCALE...IT SHOULD EVENTUALLY CONGLOMERATE INTO A LINE OF STRONG TO SEVERE CONVECTION AS IT MOVES SOUTHEAST INTO THE CWA. AT THIS TIME...IT APPEARS THAT THE BULK OF THIS ACTIVITY WILL BE ALONG AND TO THE WEST OF U.S. 65 AS IT PASSES THROUGH SOUTHERN MISSOURI. THE MAIN SEVERE WEATHER CONCERN THIS EVENING WILL BE DAMAGING STRAIGHT LINE WINDS. THE 00Z SGF SOUNDING DEPICTS EXTREME INSTABILITY...WITH LOW LEVEL THETA-E DIFFERENTIALS IN THE NEIGHBORHOOD OF 35-40K. THIS SUGGESTS A FAIRLY HIGH WIND POTENTIAL WITH ANY STORMS...WITH GUSTS IN EXCESS OF 70 MPH POSSIBLE. MUCH OF TONIGHT`S ACTIVITY WILL BE OUTFLOW DOMINATE IN NATURE...REDUCING THE TORNADO THREAT TO VERY LOW LEVELS. SOME SEVERE HAIL WILL ALSO BE POSSIBLE WITH SOME OF THE STRONGER CELLS...BUT THE HAIL THREAT SHOULD DECREASE WITH TIME AS CONVECTION CONGEALS INTO A LINE. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 330 PM CDT THU JUN 27 2013 WARM AND HUMID CONDITIONS ARE OCCURRING ACROSS THE REGION THIS AFTERNOON. TEMPERATURES ARE GENERALLY IN THE LOWER TO MIDDLE 90S WITH HEAT INDEX VALUES IN THE 100 TO 109 RANGE...WITH THE HIGHEST READINGS OCCURRING ALONG AND SOUTHWEST OF AN OSCEOLA TO SPRINGFIELD TO ALTON MISSOURI LINE. THESE CONDITIONS WILL PERSIST THROUGH THE REMINDER OF THE AFTERNOON HOURS INTO EARLY THIS EVENING. WILL KEEP THE HEAT ADVISORY GOING AS IS UNTIL 8 PM FOR THESE LOCATIONS. AN OUTFLOW BOUNDARY THAT DEVELOPED WITH CONVECTION ACROSS NORTHERN MISSOURI THIS MORNING IS CURRENTLY PUSHING SOUTH ACROSS THE AREA THIS AFTERNOON. THE AREA REMAINS FAIRLY CAPPED DUE TO A WARM AIRMASS...AND VERY LITTLE DEVELOPMENT HAS OCCURRED ON THIS BOUNDARY. A FEW ISOLATED STORMS HAVE BEEN ABLE TO DEVELOP ACROSS CENTRAL MISSOURI AND MAY REMAIN POSSIBLE ACROSS THE EASTERN OZARKS THIS AFTERNOON AS THE OUTFLOW PUSHES SOUTH...THOUGH MOST LOCATIONS SHOULD REMAIN DRY. A SURFACE FRONT IS CURRENTLY LOCATED ACROSS NORTHERN AND WESTERN KANSAS THIS AFTERNOON AND STORMS ARE BEGINNING TO DEVELOP ON THIS BOUNDARY. THIS TREND WILL CONTINUE THIS AFTERNOON AND THESE STORMS WILL FORM INTO A LINE LATER THIS AFTERNOON AND WILL ACCELERATE TO THE SOUTHEAST TOWARDS THE AREA THIS EVENING...EXITING THE AREA OVERNIGHT. LOCATIONS WITH THE BETTER POTENTIAL TO BE AFFECTED BY THIS ACTIVITY WILL BE FARTHER TO THE WEST...GENERALLY ALONG AND WEST OF HIGHWAY 65. THERE ARE MORE QUESTIONS HOW FAR EAST OF HIGHWAY 65 THIS ACTIVITY CAN MAKE IT....THOUGH THUNDERSTORMS ARE STILL POSSIBLE EAST OF HIGHWAY 65 THIS EVENING INTO THE OVERNIGHT HOURS. THE FORCING ALONG THE FRONT/COLD POOL THAT DEVELOPS FROM THE STORMS ACROSS KANSAS SHOULD BE ENOUGH TO BREAK THE CAP ACROSS THE AREA AND WITH STRONG THETA-E DIFFERENCE AND A VERY UNSTABLE AIRMASS WILL RESULT IN A STRONG DAMAGING WIND RISK WITH WINDS IN EXCESS OF 70 TO 80 MPH LIKELY ALONG THIS LINE WITH THE BEST POTENTIAL FOR WINDS THAT STRONG BEING WEST OF INTERSTATE 49. THERE IS A HAIL RISK...BUT WITH THESE STORMS EXPECTED TO BE LINEAR IN NATURE THIS POTENTIAL IS MORE LIMITED WITH GENERALLY UP TO QUARTERS POSSIBLE. TIMING OF THIS AREA WILL GENERALLY BE BETWEEN 7 AND 10 PM ALONG AND WEST OF THE INTERSTATE 49 CORRIDOR AND BETWEEN 8 AND MIDNIGHT WEST OF HIGHWAY 65. THERE ARE MORE QUESTIONS IF THIS LINE OF STORMS CAN MAKE IT EAST OF HIGHWAY 65...AND WILL HAVE TO SEE EXACTLY WHERE THIS LINE SETS UP ACROSS KANSAS. FRIDAY SHOULD GENERALLY BE DRY...THOUGH AN ISOLATED AFTERNOON THUNDERSTORM MAY BE POSSIBLE IF ENOUGH INSTABILITY CAN DEVELOP... THOUGH THIS POTENTIAL LOOKS REALLY LIMITED. TEMPERATURES WILL BE COOLER ON FRIDAY THAN TODAY...BUT HIGHS WILL STILL TOP OUT IN THE UPPER 80S TO THE LOWER 90S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 330 PM CDT THU JUN 27 2013 AN UPPER LEVEL LOW WILL BUILD SOUTHWEST OUT OF THE GREAT LAKES REGION OVER THE CENTRAL U.S. THIS WEEKEND THROUGH MUCH OF NEXT WEEK. THIS WILL PUSH THE UPPER LEVEL RIDGE AND HOT AND MUGGY CONDITIONS BACK TO THE WEST AND ALLOW A COOLER AIRMASS TO SPREAD INTO THE REGION. HIGHS THIS WEEKEND THROUGH NEXT WEEK WILL GENERALLY BE IN THE UPPER 70S TO THE MIDDLE 80S EACH AFTERNOON AS LOWS DROP INTO THE LOWER TO MIDDLE 60S EACH NIGHT. THERE COULD BE PERIODS OF SHOWERS AND THUNDERSTORMS AT TIMES AS THE UPPER LEVEL LOW REMAINS OVER THE REGION BUT NO SEVERE WEATHER OR WASH OUT IS EXPECTED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 630 PM CDT THU JUN 27 2013 STRONG/SEVERE CONVECTION CONTINUES TO FIRE ALONG A COLD FRONT TO THE WEST AND NORTHWEST OF THE CWA. IF THIS LINE CAN FILL IN BETWEEN SALINA AND KANSAS CITY...IT WILL LIKELY AFFECT THE TAF SITES THIS EVENING BETWEEN 02Z AND 04Z. IF IT DOESNT FILL IN...THE CURRENT CONVECTION TO THE WEST WILL LIKELY MISS OUR SITES TO THE WEST. HAVE CURRENTLY PUT IN A TEMPO GROUP...ROUGHLY USING THE LATEST HRRR AS TIMING GUIDANCE AFFECTING THE TAF SITES THIS EVENING. PRIOR TO AND AFTER THE CONVECTION...VFR CONDITIONS EXPECTED. DURING CONVECTION...GENERALLY MVFR CONDITIONS EXPECTED. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR MOZ066-067-077-078- 088>090-093>097-101>106. KS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ073-097-101. && $$ MESOSCALE...BOXELL SHORT TERM...WISE LONG TERM...WISE AVIATION...LINDENBERG
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1256 AM CDT WED JUN 26 2013 .UPDATE... ISSUED AT 1255 AM CDT WED JUN 26 2013 QUICK UPDATE TO THE FORECAST TO ACCOUNT FOR LATEST RADAR TRENDS. AREA OF SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS NORTH CENTRAL MISSOURI WILL MOVE EAST/SOUTHEAST THE REMAINDER OF THE NIGHT AFFECTING THE NORTHERN CWA. ISSUED AT 953 PM CDT TUE JUN 25 2013 THUNDERSTORMS CONTINUE TO DEVELOP ACROSS IL JUST NE OF OUR FORECAST AREA ALONG AN OLD OUTFLOW BOUNDARY. STILL EXPECTING THUNDERSTORMS TO DEVELOP ACROSS IA AHEAD OF A WEAK SHORTWAVE AND ON THE NOSE OF A SWLY LOW LEVEL JET...THEN GROW INTO AN MCS WHICH SHOULD EVENTUALLY DROP SEWD INTO NERN MO AND W CNTRL IL LATE TGT/EARLY WED MRNG. LOW TEMPERATURES TGT WILL BE QUITE MILD DUE TO SOUTHERLY SFC WINDS AND HIGH SFC DEW POINTS. GKS && .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 344 PM CDT TUE JUN 25 2013 SEVERAL THINGS TO DEAL WITH IN THE SHORT TERM TONIGHT. FIRST...STORMS DEVELOPING IN WARM SECTOR AHEAD OF MCV THAT IS SLIDING EAST THROUGH MO FROM MCS THAT WAS OVER WESTERN MO THIS MORNING...AS WELL AS VARIOUS OLD OUTFLOW BOUNDARIES. THIS ACTIVITY SHOULD DIMINISH MOST LOCATIONS BY EARLY THIS EVENING...THOUGH SOME LINGERING ACTIVITY OVER NORTHEAST MO/WEST CENTRAL IL AS MCV SLIDES EAST. THEN MODELS CONTINUE TO SHOW NEXT MCS DEVELOPING OVER IOWA. FORECAST CORFIDI VECTORS HAVE THIS MCS SLIDE SOUTHEAST TOWARDS FORECAST AREA...MAYBE EVEN MORE SOUTHERLY. SO SHOULD MOVE INTO NORTHERN PORTIONS OF FORECAST AREA BY 06Z. LATEST HRRR RUN IS EVEN FURTHER WEST WITH INITIAL DEVELOPMENT IN SOUTHERN IOWA...SO HAVE RAISED POPS A BIT FURTHER WEST. THERE IS A SLIGHT RISK OF SEVERE WEATHER...WITH THE MAIN THREATS BEING LARGE HAIL AND DAMAGING WINDS. AS FOR TEMPS...TO REMAIN RATHER MILD WITH LOWS IN THE LOW TO MID 70S OVERNIGHT. BYRD .LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY) ISSUED AT 344 PM CDT TUE JUN 25 2013 COMPLEX SCENARIO ON TAP FOR WEDNESDAY WITH LOTS OF UNCERTAINTY TO SPECIFIC FORECAST DETAILS. THE MAIN COMPLICATING FACTOR IS THE OVERNIGHT MCS EXPECTED TO IMPACT WESTERN IL AND PORTIONS OF ERN MO AND WHERE IT WILL BE LOCATED AT DAYBREAK. A CONSENSUS OF MODEL SOLUTIONS HAVE THE DECAYING MCS IN CENTERED THRU IL AT DAYBREAK WITH THE TRAILING FLANK OR BOUNDARY LOCATED ALONG THE MS RIVER IN ERN MO. THE VEERED NATURE OF THE TROPOSPHERIC WINDS AND WLY LLJ WOULD SUGGEST THIS SYSTEM SHOULD CONTINUE TO MOVE SEWD IN A DECAYING STATE THROUGH THE MORNING WITH POTENTIAL FOR SOME STORMS ON THE TRAILING BOUNDARY. STRONG HEATING SHOULD COMMENCE DURING THE DAY WITHIN THE WARM SECTOR AHEAD OF THE ENCROACHING COLD FRONT...AS WELL AS WEST OR SOUTHWEST OF ANY REMNANT BOUNDARIES. THE HEATING WILL BE MORE LIMITED WITH EASTWARD EXTENT DUE TO RESIDUAL CLOUDINESS FROM THE MORNING...BUT THE WARM SECTOR IS EXPECTED TO BECOME VERY UNSTABLE AND WEAKLY CAPPED WITH SBCAPE AOA 4000 J/KG. SCATTERED THUNDERSTORMS ARE EXPECTED TO REDEVELOP IN THE AFTERNOON WITHIN THE CONFLUENT ZONE AHEAD OF THE COLD FRONT AND WITH ANY RESIDUAL BOUNDARIES...PRIMARILY FROM EAST CENTRAL/SE MO INTO SOUTH CENTRAL AND SW IL. DEEP LAYER SHEAR OF 30-40 KTS AND THE AMOUNT OF INSTABILITY WOULD FAVOR SUPERCELL AND MULTICELL MODES. THE MORNING CONVECTION AND/OR RESIDUAL CLOUDS PRESENT SOME PROBLEMS WITH RESPECT TO THE MAGNITUDE OF HEAT. I HAVE COOLED TEMPS SLIGHTLY FROM ST LOUIS EASTWARD AND THIS IS HIGHLY DEPENDENT ON MORNING CLOUDS. GIVEN THE UNCERTAINTIES I HAVE DEFER ED ON ANY HEAT ADVISORIES WITH HEAT INDICES FORECAST IN THE 100-105 RANGE. STORMS SHOULD BE CLOSE TO EXITING THE CWA OR WILL HAVE EXITED THE CWA BY 00Z THURSDAY. EVEN IN THE WAKE OF THE INITIAL COLD FRONT/BOUNDARY...THURSDAY LOOKS LIKE ANOTHER SEASONABLY HOT DAY. IN FACT...IT IS NOT TOTALLY OUT OF THE QUESTION IT COULD BE HOTTER THAN WEDNESDAY BUT WITH LESSER HUMIDITY. THE ANTICIPATED NORTHWEST FLOW SHORTWAVE AND SECONDARY COLD FRONT WILL MOVE THROUGH THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY WITH A PROMINENT WSW LLJ AHEAD OF IT. THIS SHOULD FUEL ANOTHER MCS WHICH WILL IMPACT PORTIONS OF THE CWA. THE MODELS DIVERGE ON THE MCS TRACK WITH THE GREATEST PROBABILITY ATTM APPEARING TO BE THROUGH CENTRAL MO. MUCH COOLER AIR WILL THEN SPREAD INTO THE AREA IN THE WAKE OF THE FRONT FOR FRIDAY AND SET THE STAGE FOR A PROLONGED PERIOD OF BELOW AVERAGE TEMPERATURES INTO THE EXTENDED RANGES. THE EXTENDED RANGES WILL FEATURE AN AMPLIFIED BLOCKY UPPER AIR REGIME FROM THE ERN PACIFIC ACROSS THE CONUS INTO THE WRN ATLANTIC...WITH A STRONG UPPER HIGH/RIDGE CENTERED IN THE WRN U.S. AND DEEP TROF IN THE ERN U.S. A SERIES OF SHORT WAVES WILL DROP SSEWD DOWN THE BACKSIDE OF THE UPPER TROF AND IMPACT THE AREA ON SUNDAY AND TUESDAY REINFORCING THE "COOLER" AIR AND BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. GLASS && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1147 PM CDT TUE JUN 25 2013 THUNDERSTORMS HAVE BEGUN TO DEVELOP OVER NORTHWEST MISSOURI AND HAVE SHOWN SOME EASTWARD MOVEMENT. CURRENT MOTION WOULD PLACE IT AT KUIN AROUND 10Z. CURRENTLY EXPECT THESE STORMS TO STAY NORTH OF KCOU...THOUGH WILL NEED TO MONITOR TO SEE IT DEVELOPMENT IS FARTHER SOUTH THAN EXPECTED. THESE STORMS COULD ALSO AFFECT THE ST. LOUIS METRO TAFS...WITH STORMS REMAINING IN THE AREA INTO WEDNESDAY AFTERNOON. STORMS THROUGH SUNRISE COULD POSE A THREAT OF GUSTY WINDS...SMALL HAIL AND MVFR/IFR CONDITIONS. STRONGER THREAT FOR SEVERE THUNDERSTORMS WILL OCCUR ON WEDNESDAY AFTERNOON AS STORMS REGENERATE MAINLY SOUTH AND EAST OF THE ST. LOUIS METRO AREA. SPECIFICS FOR KSTL...THERE CONTINUES TO BE A THREAT FOR THUNDERSTORMS TOWARD SUNRISE THAT WILL CONTINUE INTO EARLY AFTERNOON. TIMING IS STILL UNCERTAIN...SO WILL KEEP VCTS FOR NOW. OTHERWISE EXPECT MAINLY DRY AND VFR CONDITIONS. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1206 AM CDT Wed Jun 26 2013 .UPDATE... Issued at 1014 PM CDT TUE JUN 25 2013 Models continue to have difficulty grasping onto how convection will unfold tonight. If 00z NAM and latest HRRR were on track we`d already have an a convective complex forming over eastern NE and northeast KS. However the latest radar and satellite data shows only a few isolated cells over eastern NE. With the h7 shortwave axis, per SPC analysis, now along the NE/IA state line trailing into central KS focus for a convective complex is shifted eastward into central IA where a considerable accas field is noted. HRRR and NAM both eventually latch onto this area over the next few hours and spread convection into northeast MO. Given the extensive accas field and some new cells popping up over central IA will highlight northeast MO with highest PoPs overnight. && .SHORT TERM...(This Evening through Wednesday) Issued at 405 PM CDT TUE JUN 25 2013 Convection across eastern Kansas, which kept our morning temperatures rather pleasant thanks to the cloud cover, finally dissipated in the early afternoon, allowing the sun to get to work heating things up. As the cloud cover has moved off, readings have begun jumping quickly towards the low 90s. The atmospheric conditions that will prevail over the next couple of days will be quite similar to today, only without the cooling effect from morning convection. Stormy activity later tonight is expected to get going in eastern Nebraska and Iowa late tonight on the nose of a nocturnal jet. Currently, expectations are that the hot and dry air that is advecting in today -- 700mb temperatures > 13C -- will effectively cap off much of eastern Kansas and western Missouri to any overnight convection. Thoughts are that any activity in Iowa overnight will likely put down a cold pool that could push some storms through north central or northeast Missouri early Wednesday morning. However, this activity is not expected to impact our temperatures appreciably...though damaging winds and torrential rain will be possible with these early morning storms. Wednesday and into Thursday, the lack of cloud cover from storms will allow temperatures to quickly bound into the 90s each day. Light winds and dew point values in 60s to low 70s will result in heat indices each day topping out around in the low 100s. In more rural locations, this will be hot and humid but manageable, however in the core of the Kansas City metropolitan area heat index values will likely spike to around 105 degrees each day. As a result, in consultation with the Kansas City MO Health Department, we are opting to issue a heat advisory for the next two days. Currently, the forecast for Friday indicates slightly cooler and drier conditions, so at this time we are not expecting to need a heat advisory beyond Thursday. .LONG TERM...(Wednesday Night through Tuesday) Issued at 405 PM CDT TUE JUN 25 2013 Backing 850 flow on Thursday will bring winds to the west and southwest through the afternoon, potentially bringing temps at that level even warmer than Weds with NAM and GFS showing 26C nudging into western MO by afternoon. These temps would translate into surface temps in the middle to upper 90s, while dewpoints remain close to 70 degrees. This would yield heat indices across ern KS/wrn MO in the 100-105 range, and being day 2 of such conditions could be stressful especially for sensitive individuals in the KC core. Amplifying upper ridge over the Rockies will strengthen the northwest flow overhead on Thursday, allowing a front to drop through the area Thursday night. This front will have an unstable airmass to work with, but warm/dry air below 800 hPa may act against widespread storms so kept PoPs limited to low chance category for now. Airmass behind the front will be relatively cooler with temperatures returning into the lower/middle 80s by the weekend. An upper shortwave trough will swing through the area on Sunday and could spark a few showers or storms, but otherwise chances appear too low to include a mention of precip through the remainder of the extended period. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday Night) Issued at 1205 AM CDT TUE JUN 25 2013 VFR conditions are expected through the entire forecast. Gusty south winds will persist for a few more hours with winds shifting to the southwest later tonight/early Wednesday morning. Winds will eventually veer to the northwest by the afternoon as high pressure moves over the region. Thunderstorms have developed well northeast of the terminals and are expected to move to the east/southeast through the night. Warm air aloft over the terminals area will preclude any convective development tonight. So the only areas that will see storms will be across northern into northeastern Missouri, impacting mainly the Kirksville and Chillicothe airspace. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...HEAT ADVISORY from 11 AM Wednesday to 7 PM CDT Thursday FOR KSZ103>105. MO...HEAT ADVISORY from 11 AM Wednesday to 7 PM CDT Thursday FOR MOZ028-029-037. && $$ UPDATE...MJ SHORT TERM...Cutter LONG TERM...Hawblitzel AVIATION...CDB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1154 PM CDT TUE JUN 25 2013 .UPDATE... ISSUED AT 953 PM CDT TUE JUN 25 2013 THUNDERSTORMS CONTINUE TO DEVELOP ACROSS IL JUST NE OF OUR FORECAST AREA ALONG AN OLD OUTFLOW BOUNDARY. STILL EXPECTING THUNDERSTORMS TO DEVELOP ACROSS IA AHEAD OF A WEAK SHORTWAVE AND ON THE NOSE OF A SWLY LOW LEVEL JET...THEN GROW INTO AN MCS WHICH SHOULD EVENTUALLY DROP SEWD INTO NERN MO AND W CNTRL IL LATE TGT/EARLY WED MRNG. LOW TEMPERATURES TGT WILL BE QUITE MILD DUE TO SOUTHERLY SFC WINDS AND HIGH SFC DEW POINTS. GKS && .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 344 PM CDT TUE JUN 25 2013 SEVERAL THINGS TO DEAL WITH IN THE SHORT TERM TONIGHT. FIRST...STORMS DEVELOPING IN WARM SECTOR AHEAD OF MCV THAT IS SLIDING EAST THROUGH MO FROM MCS THAT WAS OVER WESTERN MO THIS MORNING...AS WELL AS VARIOUS OLD OUTFLOW BOUNDARIES. THIS ACTIVITY SHOULD DIMINISH MOST LOCATIONS BY EARLY THIS EVENING...THOUGH SOME LINGERING ACTIVITY OVER NORTHEAST MO/WEST CENTRAL IL AS MCV SLIDES EAST. THEN MODELS CONTINUE TO SHOW NEXT MCS DEVELOPING OVER IOWA. FORECAST CORFIDI VECTORS HAVE THIS MCS SLIDE SOUTHEAST TOWARDS FORECAST AREA...MAYBE EVEN MORE SOUTHERLY. SO SHOULD MOVE INTO NORTHERN PORTIONS OF FORECAST AREA BY 06Z. LATEST HRRR RUN IS EVEN FURTHER WEST WITH INITIAL DEVELOPMENT IN SOUTHERN IOWA...SO HAVE RAISED POPS A BIT FURTHER WEST. THERE IS A SLIGHT RISK OF SEVERE WEATHER...WITH THE MAIN THREATS BEING LARGE HAIL AND DAMAGING WINDS. AS FOR TEMPS...TO REMAIN RATHER MILD WITH LOWS IN THE LOW TO MID 70S OVERNIGHT. BYRD .LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY) ISSUED AT 344 PM CDT TUE JUN 25 2013 COMPLEX SCENARIO ON TAP FOR WEDNESDAY WITH LOTS OF UNCERTAINTY TO SPECIFIC FORECAST DETAILS. THE MAIN COMPLICATING FACTOR IS THE OVERNIGHT MCS EXPECTED TO IMPACT WESTERN IL AND PORTIONS OF ERN MO AND WHERE IT WILL BE LOCATED AT DAYBREAK. A CONSENSUS OF MODEL SOLUTIONS HAVE THE DECAYING MCS IN CENTERED THRU IL AT DAYBREAK WITH THE TRAILING FLANK OR BOUNDARY LOCATED ALONG THE MS RIVER IN ERN MO. THE VEERED NATURE OF THE TROPOSPHERIC WINDS AND WLY LLJ WOULD SUGGEST THIS SYSTEM SHOULD CONTINUE TO MOVE SEWD IN A DECAYING STATE THROUGH THE MORNING WITH POTENTIAL FOR SOME STORMS ON THE TRAILING BOUNDARY. STRONG HEATING SHOULD COMMENCE DURING THE DAY WITHIN THE WARM SECTOR AHEAD OF THE ENCROACHING COLD FRONT...AS WELL AS WEST OR SOUTHWEST OF ANY REMNANT BOUNDARIES. THE HEATING WILL BE MORE LIMITED WITH EASTWARD EXTENT DUE TO RESIDUAL CLOUDINESS FROM THE MORNING...BUT THE WARM SECTOR IS EXPECTED TO BECOME VERY UNSTABLE AND WEAKLY CAPPED WITH SBCAPE AOA 4000 J/KG. SCATTERED THUNDERSTORMS ARE EXPECTED TO REDEVELOP IN THE AFTERNOON WITHIN THE CONFLUENT ZONE AHEAD OF THE COLD FRONT AND WITH ANY RESIDUAL BOUNDARIES...PRIMARILY FROM EAST CENTRAL/SE MO INTO SOUTH CENTRAL AND SW IL. DEEP LAYER SHEAR OF 30-40 KTS AND THE AMOUNT OF INSTABILITY WOULD FAVOR SUPERCELL AND MULTICELL MODES. THE MORNING CONVECTION AND/OR RESIDUAL CLOUDS PRESENT SOME PROBLEMS WITH RESPECT TO THE MAGNITUDE OF HEAT. I HAVE COOLED TEMPS SLIGHTLY FROM ST LOUIS EASTWARD AND THIS IS HIGHLY DEPENDENT ON MORNING CLOUDS. GIVEN THE UNCERTAINTIES I HAVE DEFER ED ON ANY HEAT ADVISORIES WITH HEAT INDICES FORECAST IN THE 100-105 RANGE. STORMS SHOULD BE CLOSE TO EXITING THE CWA OR WILL HAVE EXITED THE CWA BY 00Z THURSDAY. EVEN IN THE WAKE OF THE INITIAL COLD FRONT/BOUNDARY...THURSDAY LOOKS LIKE ANOTHER SEASONABLY HOT DAY. IN FACT...IT IS NOT TOTALLY OUT OF THE QUESTION IT COULD BE HOTTER THAN WEDNESDAY BUT WITH LESSER HUMIDITY. THE ANTICIPATED NORTHWEST FLOW SHORTWAVE AND SECONDARY COLD FRONT WILL MOVE THROUGH THE AREA LATE THURSDAY NIGHT INTO EARLY FRIDAY WITH A PROMINENT WSW LLJ AHEAD OF IT. THIS SHOULD FUEL ANOTHER MCS WHICH WILL IMPACT PORTIONS OF THE CWA. THE MODELS DIVERGE ON THE MCS TRACK WITH THE GREATEST PROBABILITY ATTM APPEARING TO BE THROUGH CENTRAL MO. MUCH COOLER AIR WILL THEN SPREAD INTO THE AREA IN THE WAKE OF THE FRONT FOR FRIDAY AND SET THE STAGE FOR A PROLONGED PERIOD OF BELOW AVERAGE TEMPERATURES INTO THE EXTENDED RANGES. THE EXTENDED RANGES WILL FEATURE AN AMPLIFIED BLOCKY UPPER AIR REGIME FROM THE ERN PACIFIC ACROSS THE CONUS INTO THE WRN ATLANTIC...WITH A STRONG UPPER HIGH/RIDGE CENTERED IN THE WRN U.S. AND DEEP TROF IN THE ERN U.S. A SERIES OF SHORT WAVES WILL DROP SSEWD DOWN THE BACKSIDE OF THE UPPER TROF AND IMPACT THE AREA ON SUNDAY AND TUESDAY REINFORCING THE "COOLER" AIR AND BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS. GLASS && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1147 PM CDT TUE JUN 25 2013 THUNDERSTORMS HAVE BEGUN TO DEVELOP OVER NORTHWEST MISSOURI AND HAVE SHOWN SOME EASTWARD MOVEMENT. CURRENT MOTION WOULD PLACE IT AT KUIN AROUND 10Z. CURRENTLY EXPECT THESE STORMS TO STAY NORTH OF KCOU...THOUGH WILL NEED TO MONITOR TO SEE IT DEVELOPMENT IS FARTHER SOUTH THAN EXPECTED. THESE STORMS COULD ALSO AFFECT THE ST. LOUIS METRO TAFS...WITH STORMS REMAINING IN THE AREA INTO WEDNESDAY AFTERNOON. STORMS THROUGH SUNRISE COULD POSE A THREAT OF GUSTY WINDS...SMALL HAIL AND MVFR/IFR CONDITIONS. STRONGER THREAT FOR SEVERE THUNDERSTORMS WILL OCCUR ON WEDNESDAY AFTERNOON AS STORMS REGENERATE MAINLY SOUTH AND EAST OF THE ST. LOUIS METRO AREA. SPECIFICS FOR KSTL...THERE CONTINUES TO BE A THREAT FOR THUNDERSTORMS TOWARD SUNRISE THAT WILL CONTINUE INTO EARLY AFTERNOON. TIMING IS STILL UNCERTAIN...SO WILL KEEP VCTS FOR NOW. OTHERWISE EXPECT MAINLY DRY AND VFR CONDITIONS. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
157 AM EDT WED JUN 26 2013 .SYNOPSIS... WEAK DISTURBANCES WILL CROSS THE AREA THROUGH WEDNESDAY...WITH SCATTERED SHOWERS OR THUNDERSTORMS ANTICIPATED...BUT ALSO SIGNIFICANT PERIODS OF RAIN-FREE WEATHER. BY THURSDAY...A STRONGER SYSTEM WILL APPROACH...AND IS EXPECTED TO BRING MORE PERSISTENT SHOWERS AND THUNDERSTORMS. MUGGY AND SEASONABLY WARM CONDITIONS WILL CONTINUE...WITH HIGHS MOSTLY IN THE 80S THROUGH THE END OF THE WEEK. && .NEAR TERM /THROUGH TODAY/... 10 UPDATE...CONV CONTS TO FIRE ACROSS CNTRL PA AHD OF A PARADE OF WEAK SHRT WVS IN THE WLY FLOW. HRRR SEMS TO HAVE THE BEST HANDLE ON THE CONV AND CONTS THE PCPN...WITH SLOW WEAKENING OVRNGT. WILL CONT WITH CHANCE POPS OVER THE SRN ZONES AND SLGT CHANCE ELSEWHERE FOR ROGUE SHWRS FIRING FURTHER NORTH. PLENTY OF CLDS UPSTREAM AS WELL SO FOG SHD NOT BE A BIG CNCRN OVERNGT. PRVS DISC BLO. 345 PM UPDATE... ONE BATCH OF CONVECTION IS EXITING OUR ERN ZNS LATE THIS AFTN...ASSOCD WITH A DEPARTING MCV. CNY/NE PA SHOULD EXPERIENCE A RELATIVE LULL/RAIN-FREE PD THROUGH 22-00Z. BY EARLY EVE...AN ORGANIZING BAND OF SHRA/TSRA...FROM SRN ONT ACRS LK ERIE AND ERN OH ATTM...IS EXPECTED TO COME EWD...AND COULD WELL IMPACT SRN PTNS OF THE FA. THERE IS SOME UNCERTAINTY REGARDING LINGERING AMTS OF INSTAB BY THIS TIME...BUT IT WILL LIKELY STILL BE UNSTABLE ENOUGH FOR AT LEAST SCTD COVERAGE. GIVEN INCREASED VERT SHEAR THIS EVE (0-3 KM VALUES NEAR 40 KT)...STORMS WILL HAVE TO BE WATCHED FOR WIND POTENTIAL...SHOULD THEY ORGANIZE INTO LINEAR FEATURES. LTR TNT...WE SHOULD SEE A SHORT BREAK IN PCPN ONCE AGN. SINCE THERE IS PLENTY OF CLOUD DEBRIS UPSTREAM TO THE W ATTM...WE ANTICIPATE PTLY TO MOSTLY CLDY SKIES MUCH OF THE NGT...AND THIS CLOUD COVER SHOULD CUT DOWN ON THE RADIATIONAL COOLING/FOG POTENTIAL. TWDS DAYBREAK...ANOTHER INCOMING UPR-LVL WAVE COULD BRING A ROUND OF SHWRS...AND WE`VE THUS BROUGHT CHC/SCTD POPS IN FROM THE W AFTER 08-09Z. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... 4 PM UPDATE... AN UPR-LVL WAVE WILL CROSS NY/PA WED...MAINLY IN THE AM HRS (BEFORE 18Z). SUCH EARLY TIMING WOULD SUGGEST NON-SVR STORMS...WITH PERHAPS INSUFFICIENT TIME FOR ADEQUATE DESTABILIZATION...BEFORE THE WV BEGINS TO DEPART...WITH DIMINISHING ACTIVITY IN THE AFTN. FOR NOW...WE GRADUALLY TAPER CHC/SCTD POPS BACK...FROM NW TO SE...AFTER 18Z. THE NEXT STGR UPR-LVL SYSTEM IS PROGGED TO DIG INTO THE ERN LKS/OH VLY RGN LATE WED NGT/THU. AT THIS EARLY JUNCTURE...MOST OF WED NGT SHOULD FEATURE EITHER NO PCPN...OR JUST HIT AND MISS SHWR ACTIVITY. HOWEVER...LATE AT NGT INTO THU AM...OUR CHCS FOR SHWRS/THUNDER SHOULD INCREASE...AS UPR-LVL JET FORCING AND MOISTURE ADVECTION IMPROVE. THERE REMAIN SUBTLE MODEL POSITIONING DIFFS ON THU...BUT THE MAIN SYNOPTIC IDEA IS FOR A FAIRLY AMPLIFIED UPR-LVL WAVE TO SLOWLY LIFT FROM THE OH VLY INTO THE NERN STATES...WITH A PRETTY WELL DEFINED SFC LOW FOR THIS TIME OF YEAR...TRANSLATING NEWD ACRS PA AND NY STATE. THUS...WE`VE BUMPED POPS INTO THE LIKELY/NUMEROUS RANGES. DEPENDING ON SPECIFICALLY WHERE THE SFC LOW TRACKS...THE WARM SECTOR DVLPS...AND THE EXTENT OF CLOUD COVER/SFC HEATING...THERE IS POTENTIAL FOR SVR STORMS (GOOD LOW-LVL DIR SHEAR AND VERT SPEED SHEAR). WE`LL SIMPLY HAVE TO SEE HOW THINGS EVOLVE OVER THE NEXT COUPLE OF DAYS. FOR NOW...WE`LL CONTINUE TO HIGHLIGHT THIS POTENTIAL IN THE HWO. && .LONG TERM /FRIDAY THROUGH TUESDAY/... VERY FEW CHANGES MADE TO THE EXTENDED TIME FRAME WITH THE EXCEPTION OF INCREASING POPS INTO THE LIKELY CATEGORY THIS WEEKEND INTO EARLY NEXT WEEK AS MODEL TRENDS CONTINUE TO FAVOR A VERY WET SCENARIO IN COMING DAYS. MAIN CULPRITS CONTINUE TO BE DEVELOPING RIDGING ACROSS BOTH THE NORTHERN ATLANTIC AND INTERMOUNTAIN WEST...WITH ALL MODELS ALSO SHOWING A DIGGING UPPER-LEVEL TROUGH EXTENDING FROM THE CENTRAL GREAT LAKES SOUTH INTO THE LWR MISS RVR VLY. CONCERNS CONTINUE TO INCREASE THAT TROPICAL CONNECTIONS WILL BECOME FIRMLY ESTABLISHED BY THE WEEKEND AS THE GULF OF MEXICO AND WESTERN ATLANTIC REMAIN WIDE-OPEN FOR STRONG LOW-LEVEL MOISTURE TRANSPORT NORTH ALONG THE ATLANTIC SEABOARD. AS A RESULT...FELT COMPELLED TO INCREASE POPS ACCORDINGLY...WHICH AGREES WELL WITH LATEST 12Z WPC GUIDANCE. TRENDS WILL HAVE TO BE MONITORED IN COMING DAYS...BUT THE DEVELOPING SYNOPTIC PATTERN LOOKS EERILY SIMILAR TO PATTERNS RESPONSIBLE FOR PAST LARGE-SCALE EAST COAST FLOOD EVENTS. STAY TUNED! && .AVIATION /06Z WEDNESDAY THROUGH THURSDAY NIGHT/... 200 AM EDT UPDATE... A FEW ISOLATED SHOWERS ARE LINGERING ACROSS CENTRAL NY EARLY THIS MORNING. THIS ACTIVITY WILL SLOWLY DIMINISH OVER THE NEXT FEW HOURS. LOW LEVEL MOISTURE WILL CREEP INTO CENTRAL NY THIS MORNING FROM THE WEST AND WITH THE SHOWERS DIMINISHING... A LOW STRATUS DECK NEAR 2500 FT MAY FORM ACROSS THE REGION AND LAST FOR A FEW HOURS. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE AREA WEDNESDAY MORNING/AFTERNOON. THIS ACTIVITY WILL DISRUPT THE STRATUS DECK AND VFR CONDITIONS WILL RETURN WITH MVFR VISIBILITIES. THIS ROUND OF STORMS WILL PUSH THROUGH THE REGION BY LATE AFTERNOON AND VFR CLOUD DECKS WILL LINGER IN THE PASSING OF THE SYSTEM. OUTLOOK...FRI THROUGH SUN... FRI...MAINLY VFR. EARLY MORNING MVFR/IFR IN VALLEY FOG. SAT...MVFR RESTRICTIONS POSSIBLE IN DEVELOPING RA. SUN...MVFR POSSIBLE IN SHOWERS/STORMS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DGM/MLJ NEAR TERM...DGM/MLJ SHORT TERM...MLJ LONG TERM...CMG AVIATION...KAH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1017 PM EDT THU JUN 27 2013 .SYNOPSIS... UNSETTLED WEATHER WILL CONTINUE THROUGH THE MIDDLE OF NEXT WEEK WITH A DAILY RISK OF SHOWERS AND THUNDERSTORMS. SIGNIFICANT RAINFALL AMOUNTS ARE EXPECTED THROUGH THE PERIOD AND THIS RAIN WILL BE FALLING ON ALREADY WET SOILS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...THE LAST IN THE SERIES OF SHORTWAVE DISTURBANCES ALOFT WILL PUSH ACROSS THE EASTERN CAROLINAS IN THE NEXT SEVERAL HOURS...LIKELY SUSTAINING CONVECTION ACROSS THE AREA THROUGH MIDNIGHT AND PERHAPS BEYOND. WITH SUCH A HUMID AIRMASS (PRECIPITABLE WATER 2.0 TO 2.1 INCHES AND SURFACE DEWPOINTS IN THE 70S) VIRTUALLY ANY STORM CELL IS PRODUCING RAINFALL RATES IN EXCESS OF 1 INCH PER HOUR. BASED MAINLY ON CURRENTLY OBSERVED RADAR TRENDS I HAVE ADJUSTED POPS UP FOR THE NEXT 3-4 HOURS TO 100 PERCENT FROM EASTERN COLUMBUS COUNTY THROUGH THE WILMINGTON METRO AREA...AND JUST SOUTH OF FLORENCE TO NEAR KINGSTREE. THIS ACTIVITY IS PROBABLY NO LONGER SURFACE BASED BUT IS TAKING ADVANTAGE OF A STRENGTHENING LOW LEVEL JET WHICH IS ADVECTING IN EXTREMELY HUMID AIR OFF THE ATLANTIC WITH DEWPOINTS IN THE UPPER 70S. FLOOD ADVISORIES OR WARNINGS MAY NEED TO BE ISSUED IN THE NEXT HOUR OR TWO GIVEN THE SLOW OBSERVED CELL MOTION COUPLED WITH HIGH RAINFALL RATES. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A SERIES OF TWO UPPER LEVEL DISTURBANCES ROLLING ACROSS A STRONGLY UNSTABLE AIRMASS LED TO THE DEVELOPMENT OF WIDESPREAD THUNDERSTORMS THIS AFTERNOON. SURFACE-BASED INSTABILITY IS NOW WANING WITH THE LOSS OF INSOLATION AND THE LARGE-SCALE OVERTURNING OF THE AIRMASS. HOWEVER CONSIDERABLE INSTABILITY (CAPE: 3000 J/KG) REMAINS SOUTH AND WEST OF FLORENCE WITH LESSER INSTABILITY ALONG THE COAST FROM MYRTLE BEACH THROUGH WILMINGTON. (A SMALL NEGATIVE REGION OF CONVECTIVE INHIBITION ALONG THE COAST COULD PREVENT THIS INSTABILITY FROM BEING REALIZED) SYNOPTIC MODELS ARE OFTEN OF LITTLE USE IN FORECASTING CONVECTION. THE HRRR HIGH-RESOLUTION MODEL IS HAVING TROUBLE INITIALIZING THE STORM PROPERLY BUT THE LAST SEVERAL RUNS SUGGEST THE INSTABILITY SOUTH OF FLORENCE TOWARD THE SANTEE RIVER INTO THE CHARLESTON METRO AREA WILL BE THE BREEDING GROUND FOR ANOTHER CLUSTER OF CONVECTION OVER THE NEXT SEVERAL HOURS. THE FINAL UPPER LEVEL SHORTWAVE MOVING SOUTHEAST THROUGH THE PIEDMONT REGION COULD ALSO IGNITE NEW STORMS ACROSS THE SANDHILLS IN THE NEXT FEW HOURS WITH THE INTERSTATE 95 CORRIDOR POTENTIALLY RECEIVING ANOTHER ROUND OF ACTIVITY. IN TERMS OF FORECAST POPS...I HAVE THE HIGHEST POPS FOR THE NEXT FEW HOURS ACROSS NORTHERN ROBESON INTO BLADEN COUNTIES IN NC. BY LATE THIS EVENING I SHIFT THE BULLSEYE SOUTHWARD FROM JUST INLAND OF GEORGETOWN ACROSS CENTRAL HORRY COUNTY TO NEAR WILMINGTON. (50-60 PERCENT) AFTER MIDNIGHT MOST OF THE CONVECTIVE ACTIVITY SHOULD SHIFT OFFSHORE BEHIND THE FINAL SHORTWAVE ALOFT...WITH DRYING CONDITIONS TEMPORARILY BUILDING IN FROM THE WEST. I SAY TEMPORARILY BECAUSE THE PATTERN FOR TOMORROW AFTERNOON THROUGH THE WEEKEND IS WET TO SAY THE LEAST! FORECAST LOWS TONIGHT RANGE FROM 72-77...COOLEST WEST OF I-95 AND WARMEST ALONG THE COAST. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...A BROAD UPPER LOW ACROSS THE GREAT LAKES WILL SLOWLY RELOCATE ACROSS THE OHIO VALLEY DURING THIS PERIOD. MID-LEVEL SHORTWAVE ENERGY ROTATING AROUND THE UPPER LOW WILL HELP TO ENHANCE SHOWERS AND THUNDERSTORMS. SURFACE FEATURES THAT WILL HELP TO CONVERGE AND LIFT A MOIST AND UNSTABLE AIRMASS INCLUDE THE SEABREEZE AND THE PIEDMONT TROUGH. OVERALL...A WET PERIOD IS IN STORE WITH BOUTS OF SHOWERS AND THUNDERSTORMS. RAINFALL AMOUNTS JUST DURING THIS PERIOD WILL LIKELY ADD ANOTHER 1 TO 2 INCHES TO WHAT HAS BEEN A VERY WET JUNE ALREADY. AS IS USUALLY THE CASE WITH CONVECTION...SOME SPOTS COULD RECEIVE AMOUNTS CONSIDERABLY HIGHER THAN THIS RANGE. IT LOOKS AS THOUGH ONE SUCH SHORTWAVE WILL LIFT OUT ACROSS THE EASTERN CAROLINAS DURING FRI AFTERNOON. MIXED LAYER CAPE VALUES ARE VERY HIGH ON FRI...REACHING 3000 J/KG. MID-LEVEL LAPSE RATES ARE HOWEVER MODEST. THE FLOW IS LARGELY WESTERLY...EXCEPT SW IN THE LOWEST 3-5 KFT OR SO. THERE IS CONSIDERABLE DRY AIR IN THE MID-LEVELS FRI MORNING...BUT THEN OVERTIME...THE COLUMN MOISTENS FROM W TO E...DURING THE AFTERNOON AND EVE. THUS...THE SCENARIO PAINTED BY SEVERAL OF THE MODELS LOOKS REASONABLE...SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THE PIEDMONT TROUGH IN RESPONSE TO STRONG HEATING AND MOVING ACROSS OUR WESTERN ZONES FRI AFTERNOON AND THEN TO THE COAST FRI EVE/NIGHT. A FEW STORMS MAY ALSO POP ALONG THE SEABREEZE FRI AFTERNOON. GIVEN THE MAGNITUDE OF INSTABILITY AND DEVELOPING INVERTED V SOUNDINGS...THERE IS A RISK FOR STRONG TO POSSIBLY DAMAGING WINDS IN THE DEEPEST CONVECTION. MID-LEVEL TEMPS SHOULD BE COOL ENOUGH TO SUPPORT HAIL IN ANY STRONG AND PERSISTENT UPDRAFTS. THIS IS IN ADDITION TO THE HEAVY RAIN AND FREQUENT DEADLY LIGHTING RISK. THE CONVECTION SHOULD ONLY SLOWLY WANE WITH LOSS OF HEATING THROUGH THE LATE EVE AND OVERNIGHT. SAT...THE FLOW TURNS MORE SOUTHWESTERLY THROUGH A DEEP LAYER AND THERE IS NO DRY AIR IN THE COLUMN TO BE FOUND. THE COLUMN IS SATURATED OR NEARLY SO THROUGH A DEEP LAYER. SOME OF THE MODELS ARE INDICATING A SHORTWAVE TROUGH MOVING UP THE COAST...BUT A GOOD DISTANCE OFFSHORE. WE WILL HAVE TO WATCH THIS FEATURE TO SEE HOW IT EVENTUALLY PLAYS OUT. THERE MAY BE SOME SUBSIDENCE DEVELOPING ON THE BACK SIDE WHICH WOULD TEND TO SUPPRESS/REDUCE CONVECTION. HOWEVER...CLOSER TO THE COAST AND THERE COULD BE CONSIDERABLE CONVECTION AT AND NEAR THE COAST. GIVEN THE ENVIRONMENT...IT WILL TAKE VERY LITTLE TO IGNITE CONVECTION. STORM MOTIONS SHOULD BE MUCH QUICKER ON SAT THAN ON FRI AS THE WIND FIELDS WILL BE STRONGER. WET MICROBURSTS CAN NOT BE RULED OUT ON SAT. CLOUD COVER SHOULD BE MORE WIDESPREAD SAT THAN ON FRI GIVEN THE EXPECTED MOISTURE PROFILES. WILL THUS FORECAST HIGHER TEMPS ON FRI...LOWER TO MID 90S. THE SEABREEZE SHOULD BE PINNED NEAR THE COAST AND SO EVEN THE BEACHES SHOULD REACH THE UPPER 80S WITH THE EXCEPTION OF BRUNSWICK AND SOUTHERN NEW HANOVER COUNTIES WHERE A MORE ONSHORE FLOW SHOULD KEEP AFTERNOON TEMPS IN THE MID 80S. HIGHS ON SAT WILL BE MAINLY IN THE UPPER 80S TO AROUND 90 WELL INLAND WITH MID 80S AT THE BEACHES AS THE SEABREEZE SHOULD BE ABLE TO MAKE A LITTLE FURTHER PROGRESS INLAND. LOWS WILL BE IN THE MUGGY 70S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 3 PM THURSDAY...ACTIVE WEATHER WILL CONTINUE THROUGH AT LEAST THE FIRST HALF OF THE WEEK. MID TO UPPER TROUGH DIGGING DOWN THROUGH THE MISSISSIPPI VALLEY ON SUNDAY WILL LIFT TOWARD THE NORTHWEST AS STRONG UPPER RIDGE TO OUR EAST TRIES TO BUILD WESTWARD ACROSS THE EAST COAST. INITIALLY LOCAL AREA WILL REMAIN BETWEEN THESE TWO FEATURES ON THE ACTIVE SIDE OF MID TO UPPER TROUGH. SHORTWAVE ENERGY WILL ROTATE AROUND THE TROUGH UP THROUGH THE CAROLINAS ENHANCING LOCALIZED CONVECTION SUNDAY THROUGH MID WEEK. THE CONVECTION SHOULD FIRST FIRE UP OVER THE SEA BREEZE CONVERGENT BOUNDARY AND THE PIEDMONT TROUGH INLAND BUT THEN WILL BECOME MORE WIDESPREAD ALONG MESO OUTFLOW BOUNDARIES. OVERALL WILL REMAIN IN DEEP MOIST SOUTHERLY FLOW AND EXPECT PLENTY OF CLOUDS AND CONVECTION EACH DAY IN A WARM AND HUMID SUMMERTIME AIR MASS. THE STEERING FLOW WILL KEEP STORMS MOVING FROM SOUTH TO NORTH AND MAY ALLOW FOR BETTER WEATHER ALONG THE IMMEDIATE COAST. AS MID TO UPPER TROUGH LIFTS FARTHER NORTH INTO CANADA THE RIDGE MAY MAKE IT FAR ENOUGH WEST TO PROVIDE SOME SUBSIDENCE AND DRYING THROUGH THE MID LEVELS OF THE ATMOSPHERE BY WED OR THURS. WITHOUT THE UPPER LEVEL SUPPORT WE CAN GET BACK TO LESS IN THE WAY OF STRONGER CONVECTION AND JUST LOCALIZED SHOWER ACTIVITY ALONG THE SEA BREEZE AND PIEDMONT TROUGH. TEMPS WILL RUN NEAR OR ABOVE NORMAL THROUGH THE PERIOD WITH 70S FOR OVERNIGHT LOWS AND CLOSE TO 90 FOR AFTERNOON HIGHS. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AS OF 00Z...SEVERAL BANDS OF SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE TERMINAL AREA THIS EVENING. WITH STRONG INSTABILITY AND A MOIST AIRMASS THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH 03Z AT KFLO/KLBT AND THROUGH 06Z AT THE COASTAL TERMINALS. VFR IS EXPECTED OUTSIDE OF PRECIPITATION. SINCE PRECIPITATION IS MOVING RATHER QUICKLY FEEL TEMPO MVFR CONDITIONS WILL BE MOST LIKELY WITH THIS ACTIVITY...BUT BRIEF IFR/LIFR COULD CERTAINLY OCCUR AS WELL AS VARIABLE WIND GUSTS TO 30 KTS IF A CELL MOVES DIRECTLY OVER ANY TERMINAL. PER RADAR LOOPS KLBT/KFLO WILL HAVE THE BEST CHANCE OF THUNDERSTORMS THROUGH 02Z-03Z WITH LOWER CONFIDENCE OF OCCURRENCE AT KFLO. AFTER 06Z EXPECT ONLY ISOLATED SHOWERS...AND THAT MOST LIKELY AT THE COASTAL TERMINALS THROUGH SUNRISE. VFR EXPECTED AT THE COASTAL TERMINALS THROUGH SUNRISE BUT THERE IS MODERATE CONFIDENCE IFR CIGS/MVFR VSBYS COULD AGAIN DEVELOP AT KFLO/KLBT 08-12Z. EXPECT THE SAME PATTERN OF CONVECTIVE ACTIVITY FOR FRIDAY WITH GENERALLY VFR CONDITIONS...SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE SEA BREEZE DURING THE MORNING AND NEAR KFLO/KLBT DURING THE AFTERNOON. EXTENDED OUTLOOK...ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS THROUGH TUESDAY WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...NEW THUNDERSTORMS ARE MOVING OFF THE COAST NORTH OF CAPE FEAR. THESE STORMS MAY BE FOLLOWED BY MORE WAVES OF STORMS OVERNIGHT AS ANOTHER UPPER LEVEL DISTURBANCE PUSHES OFF THE COAST. THE UPDATED FORECAST FEATURES INCREASED THUNDERSTORM POTENTIAL THROUGH ABOUT 2-3 AM FRIDAY...WITH LESSENING CHANCES LATE TONIGHT. ALTHOUGH SYNOPTIC-SCALE WINDS WILL REMAIN FROM THE SOUTHWEST AT 15-25 KNOTS...OBVIOUSLY THUNDERSTORM-SCALE WINDS MUCH TOO SMALL TO FORECAST MORE THAN 1-2 HOURS IN ADVANCE WILL DOMINATE THE WEATHER THROUGH THE NIGHT. MARINERS SHOULD CLOSELY WATCH FOR THESE STORMS AS THEY ARE PRODUCING CONTINUOUS LIGHTNING... TORRENTIAL RAINFALL AND REDUCED VISIBILITIES...AND STRONG GUSTY WINDS. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A FAIRLY TIGHT PRESSURE GRADIENT EXISTS BETWEEN A PIEDMONT TROUGH NEARLY STATIONARY INLAND AND THE BERMUDA HIGH WELL OFFSHORE. THIS IS PRODUCING A HEALTHY SOUTH-SOUTHWEST BREEZE AT 15-25 KNOTS THIS EVENING. ALTHOUGH MODELS SUGGEST WIND SPEEDS WILL RELAX A LITTLE AFTER MIDNIGHT...THE TIGHT GRADIENT SHOULD REMAIN WITH STRONGER WINDS REDEVELOPING FRIDAY. SEVERAL CLUSTERS OF THUNDERSTORMS INLAND ARE WEAKENING AS THEY APPROACH THE COAST...BUT THE POTENTIAL REMAINS FOR REDEVELOPMENT OF SHOWERS AND STORMS ACROSS THE COASTAL WATERS...MAINLY FROM LATE THIS EVENING THROUGH ABOUT 3 AM FRIDAY. THUNDERSTORMS CHANCES ARE SLIGHTLY HIGHER NORTH OF MYRTLE BEACH BUT I CAN`T RULE OUT STORMS ACROSS THE SC WATERS EITHER. I HAVE MADE SUBSTANTIAL EDITS TO SEA HEIGHTS BASED ON DATA FROM THE OCEAN CREST PIER WAVE GAUGE WHICH IS REPORTING 3-4 FT SEAS JUST OUTSIDE THE SURF ZONE. LARGER SEAS OFTEN PENETRATE RIGHT UP TO THE BEACHES ON A GOOD ONSHORE WIND HERE...AN EFFECT EVEN OUR HIGH RESOLUTION "SWAN" WAVE MODEL DOESN`T SEEM TO BE ABLE TO HANDLE. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...A SMALL CRAFT ADVISORY HAS BEEN EXTENDED FOR ALL AREAS UNTIL 6 PM SAT. THE PRESSURE GRADIENT BETWEEN A PIEDMONT TROUGH INLAND AND THE BERMUDA RIDGE WILL HELP TO KEEP WINDS AND SEAS ELEVATED THIS PERIOD. WINDS WILL REACH UP TO 20 TO 25 KT. WINDS WILL BE SW THROUGH THE PERIOD...SLIGHTLY MORE W OF S ON FRI THAN ON SAT. SEAS WILL PEAK IN THE 4 TO 7 FT RANGE. SE...8 TO 9 SECOND SWELL... WILL BE WEAK DURING THIS PERIOD AND WAVE HEIGHTS WILL BE THE RESULT OF INCREASING WIND WAVE ENERGY. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 3 PM THURSDAY...SOUTHERLY FLOW WILL CONTINUE AROUND WESTERN PERIPHERY OF BERMUDA HIGH THROUGH EARLY NEXT WEEK. GRADIENT WILL REMAIN FAIRLY TIGHT THROUGH THE WEEKEND BETWEEN LOW AND PIEDMONT TROUGH INLAND AND HIGH PRESSURE OFF SHORE. WINDS WILL GENERALLY BE AROUND 15 KTS NEAR SHORE WITH A SPIKE UP EACH AFTN IN SEA BREEZE. WINDS WILL BE UP AROUND 20 IN OUTER WATERS AND UP TO 25 KTS IN WATERS NORTH FRYING PAN. PERSISTENT SOUTHERLY FLOW WILL KEEP SEAS UP AROUND 4 TO 6 FT THROUGH THE PERIOD. WILL MOST LIKELY END UP WITH AN EXTENDED PERIOD OF SMALL CRAFT ADVISORY CONDITIONS FOR 6 TO 7 FT SEAS IN STRONGER SOUTHERLY FLOW ESPECIALLY IN OUTER WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252- 254-256. && $$ NEAR TERM...TRA SHORT TERM...RJD LONG TERM...RGZ AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
935 PM EDT THU JUN 27 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL HOLD OVER THE REGION FOR THE NEXT SEVERAL DAYS... AS A LARGE LOW PRESSURE TROUGH HOLDS OVER THE EASTERN HALF OF THE COUNTRY. PASSING UPPER LEVEL DISTURBANCES WILL HELP PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH FRIDAY NIGHT/... AS OF 935 PM THURSDAY... THE LAST CLUSTER OF ORGANIZED CONVECTION CONTINUES MOVING TO THE ESE OVER THE SRN PIEDMONT AND SW SANDHILLS. OTHER MORE ISOLATED CELLS ELSEWHERE HAVE BECOME STRONG BUT THEIR HIGH-REFLECTIVITY CORES HAVE NOT QUITE REACHED THE HEIGHTS OF EARLIER STORMS. THE BOUNDARY LAYER CONTINUES TO SLOWLY BUT STEADILY STABILIZE WITH MLCAPE DOWN TO 1500 J/KG AND GROWING CINH... AND THIS TREND SHOULD CONTINUE WITH STORMS DISSIPATING IN THE NEXT FEW HOURS. THE LATEST COUPLE OF HRRR RUNS AS WELL AS THE SREF AND WRF SUPPORT THIS SCENARIO WITH REMAINING STORMS SHIFTING TO OUR EAST AND WEAKENING. DYNAMIC SUPPORT FOR ASCENT WILL BE WANING AS THE VORTICITY AXIS SHIFTS TO OUR EAST... LEAVING BEHIND BAGGY MID LEVEL TROUGHING OVERNIGHT WITH A LINGERING DIFFUSE TROUGH AT THE SURFACE THROUGH THE CENTRAL CAROLINAS. WILL HOLD ONTO EXISTING FORECAST TREND OF POPS DECREASING WEST TO EAST. EXPECT FAIR TO PARTLY CLOUDY SKIES OVERNIGHT... ALTHOUGH THE MORE WIDESPREAD SHOWERS/STORMS IN THE EAST ALONG WITH SLIGHTLY HIGHER DEW POINTS AND 925-850 MB MOISTURE SHOULD YIELD MORE WIDESPREAD STRATUS IN OUR EAST. WITH THE RAIN-COOLED AIR IN SOME AREAS... CURRENT TEMPS HAVE FALLEN TO WITHIN A FEW DEGREES OF THE DEW POINT AND HENCE ARE CLOSE TO THE NIGHTTIME LOWS. CURRENT TEMP TRENDS PLUS STATISTICAL GUIDANCE SUPPORT LOWS CLOSE TO THE CURRENT FORECAST OF 69-74. -GIH FRIDAY... SHORTWAVE ENERGY DIGGING THROUGH THE UPPER MIDWEST WILL CONTINUE TO DEEPEN THE UPPER LEVEL TROUGH DEVELOPING OVER THE EASTERN US. A SHARP PIEDMONT TROUGH WILL BE IN PLACE DURING THE DAY ON FRIDAY..WITH LITTLE CHANGE IN AIRMASS EXPECTED OUTSIDE OF SLIGHTLY LOWER DEWPOINTS IN THE WESTERN PIEDMONT. CYCLONIC FLOW ALOFT...ALBEIT WITHOUT A NOTABLE TRIGGER IN THE MODELS...AND MODEST INSTABILITY WILL ONCE AGAIN SUPPORT SCATTERED TO NUMEROUS THUNDERSTORMS DURING THE AFTERNOON. WHILE ITS POSSIBLE THAT COVERAGE MAY NOT BE AS GREAT AS THIS AFTERNOON...MID-LEVEL FLOW WILL BE STRONGER AND DEEP LAYER SHEAR IS PROGGED TO TO EXCEED 30KT...SUGGESTING MULTICELLULAR ORGANIZATION. THE CURRENT SPC DAY TWO OUTLOOK INCLUDES ALL OF CENTRAL NC IN A SLIGHT RISK. REGARDING HIGH TEMPS...GUIDANCE ALMOST UNANIMOUSLY GIVES VALUES A FEW DEGREES WARM THAN TODAY...WITH LOWER 90S ACROSS A LARGE PORTION OF THE CWA. THIS WILL LIKELY LEAD TO HEAT INDICES NEAR 100 ACROSS THE SANDHILLS AND SOUTHERN PIEDMONT WHERE DEWPOINTS SHOULD HOVER IN THE LOWER 70S. FRIDAY NIGHT... WILL CONTINUE AT LEAST A SLIGHT CHANCE OF SHOWERS AND STORMS THROUGH FRIDAY NIGHT AS HEIGHTS CONTINUE TO SLOWLY FALL ALOFT AND THE AIRMASS OVER NC REMAINS HUMID. LOWS IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM THURSDAY... AN ANOMALOUSLY AMPLIFIED PATTERN WILL PREVAIL ACROSS THE CONUS THROUGH THE WEEKEND...CHARACTERIZED BY A DEEP UPPER LEVEL RIDGE OVER THE ROCKIES/INTERMOUNTAIN WEST AND DEEP TROUGHING EAST OF THE MISSISSIPPI...WITH A PERSISTENT UPPER LEVEL LOW CENTERED IN VICINITY OF THE LOWER GREAT LAKES AND OH VALLEY. ACROSS THE CAROLINAS AND MID-ATLANTIC...EXPECT ATYPICALLY STRONG SOUTHWEST FLOW ALOFT WITH NUMEROUS SMALL AMPLITUDE SHORTWAVES CROSSING THE REGION THROUGHOUT THE PERIOD IN THE PRESENCE OF A SEASONABLY MOIST AIRMASS. AS A RESULT...EXPECT ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS AND SLIGHTLY BELOW NORMAL HIGH TEMPS IN THE MID 80S...DEPENDING ON CLOUD COVER AND CONVECTION. THE EXACT COVERAGE AND PERSISTENCE OF CONVECTION WILL HIGHLY DEPEND ON THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT AND THE TIMING OF THESE DISTURBANCES IN RELATION TO THE DIURNAL HEATING CYCLE. FURTHERMORE...THE DEGREE OF DIURNAL DESTABILIZATION IS DIFFICULT TO ASCERTAIN GIVEN INCREASED CLOUD COVER AND AN ABOVE NORMAL CHANCE FOR NOCTURNAL OR EARLY MORNING CONVECTION...THOUGH ONE WOULD EXPECT AT LEAST SOME CLOUD BREAKS AND AREAS OF RELATIVELY STRONGER INSOLATION DURING PEAK HEATING. EITHER WAY...SLIGHTLY STEEPER MID-LEVEL LAPSE RATES /COOLER TEMPS ALOFT/ IN ASSOCIATION WITH THE UNUSUALLY AMPLIFIED UPPER LEVEL TROUGH OVER THE REGION WILL AT LEAST SOMEWHAT COMPENSATE FOR DECREASED INSOLATION. GIVEN DEEP-LAYER (0-6 KM) SHEAR LIKELY IN THE 35-45 KT RANGE...ORGANIZED CONVECTION WILL CERTAINLY BE POSSIBLE... INCLUDING SUPERCELLS...THOUGH THE TYPE/EXTENT OF ANY SEVERE THREAT CANNOT BE PRECISELY IDENTIFIED AT THIS TIME. IN ADDITION TO A POTENTIAL FOR SEVERE THUNDERSTORMS...ISOLATED FLASH FLOODING WILL ALSO BE POSSIBLE GIVEN RECENT HEAVY RAINFALL AND ABOVE NORMAL CHANCES FOR CONVECTION THROUGH THE WEEKEND. -VINCENT && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY... AN UNSEASONABLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST ACROSS THE CONUS THROUGH THE MIDDLE OF NEXT WEEK...CHARACTERIZED BY RIDGING OVER THE INTERMOUNTAIN WEST...TROUGHING CENTERED IN VICINITY OF THE MS RIVER VALLEY AND ATYPICALLY STRONG SW FLOW ALOFT OVER THE CAROLINAS. NUMEROUS SMALL AMPLITUDE DISTURBANCES IN THE PRESENCE OF ABOVE NORMAL MOISTURE (PWAT ~2.00") WILL RESULT IN ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH EARLY/MID NEXT WEEK... MODULATED PRIMARILY BY THE DIURNAL HEATING CYCLE...IN ADDITION TO A CONTINUED THREAT FOR SEVERE WEATHER (GIVEN FAVORABLE DEEP-LAYER SHEAR) AND ISOLD FLASH FLOODING. IN GENERAL EXPECT HIGHS SEVERAL DEGREES BELOW NORMAL DUE TO INCREASED CLOUD COVER AND CHANCES FOR CONVECTION. -VINCENT && .AVIATION /00Z THURSDAY THROUGH TUESDAY/... AS OF 745 PM THURSDAY... SCATTERED STORMS WILL SWEEP ACROSS CENTRAL NC THROUGH 04Z. RWI/FAY ARE THE TAF LOCATIONS MOST LIKELY TO BE AFFECTED... HOWEVER THE CHANCE OF A STORM PASSING OVER ANY PARTICULAR TAF SITE IS TOO REMOTE TO INCLUDE AS A PREVAILING CONDITION. MOST STORMS THIS EVENING WILL BE CIRCUMNAVIGABLE. OTHERWISE... VFR CONDITIONS ARE EXPECTED TO HOLD THROUGH TONIGHT... WITH THE EXCEPTION OF FAY WHERE VERY MOIST AIR AND A MOIST GROUND FROM TODAY`S STORMS WILL FOSTER DEVELOPMENT OF IFR/LIFR STRATUS AND MVFR/IFR FOG 07Z-12Z TONIGHT/FRIDAY MORNING. THIS SHOULD LIFT BY 15Z... THEN VFR CONDITIONS SHOULD HOLD AT ALL SITES THROUGH 18Z. ANOTHER ROUND OF SCATTERED TO NUMEROUS STORMS OVER CENTRAL NC IS LIKELY AS WE APPROACH THE END OF THE TAF VALID PERIOD. LOOKING BEYOND 18Z FRIDAY... SHOWERS/STORMS SHOULD BE NUMEROUS ENOUGH FOR A GOOD CHANCE OF LOCALLY HEAVY RAIN AND A PERIOD OF IFR/LIFR CONDITIONS AT CENTRAL NC TAF SITES MAINLY FROM 18Z-00Z. AS VERY LITTLE CHANGES IN THE OVERALL REGIME WITH WARM AND HUMID AIR AND A LOW PRESSURE TROUGH WITH A SERIES OF DISTURBANCES PASSING OVERHEAD... NEARLY DAILY SHOWER/STORM CHANCES WITH BRIEF MVFR OR IFR CONDITIONS ARE POSSIBLE EACH AFTERNOON/EARLY EVENING... AND A PERIOD OF IFR STRATUS OR FOG MAY OCCUR EARLY EACH MORNING. -GIH && .EQUIPMENT... KRAX WSR-88D WILL BE REMAIN DOWN OR IN DEGRADED MODE THROUGH FRIDAY MORNING. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE... AND IS WORKING TO RETURN THE RADAR TO NORMAL SERVICE BY EARLY AFTERNOON FRIDAY. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BLS SHORT TERM...VINCENT LONG TERM...VINCENT AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
307 PM EDT WED JUN 26 2013 .SYNOPSIS... INCREASINGLY UNSETTLED WEATHER IS EXPECTED FOR THE REMAINDER OF THE WEEK INTO THE WEEKEND AS LOWER PRESSURE ALOFT DEEPENS OVER THE REGION. SHOWERS AND THUNDERSTORMS WILL FIRE EACH DAY ALONG AN INLAND SURFACE TROUGH...AS WELL AS THE SEA BREEZE. DAYTIME AND NIGHTTIME TEMPERATURES WILL HOLD CLOSE TO NORMAL FOR LATE JUNE TO EARLY JULY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM WEDNESDAY...CONVECTIVE CLUSTER TRACKING EASTWARD ALONG A SEA-BREEZE FRONT OVER BRUNSWICK COUNTY WILL BE MONITORED CLOSELY IN THE VERY NEAR TERM. SPS HAS HIGHLIGHTED OUR AREA FOR ISOLATED SEVERE STORMS AIDED BY CONVERGENCE BUT A WATCH APPEARS UNLIKELY. OTHER CELLS COULD THREATEN OUR NORTHERN ZONES FROM RED SPRINGS TO ELIZABETHTOWN THROUGH AFTERNOON. WEST OF ALL THIS ACTIVITY THERE APPEARS TO BE ONLY ISOLATED CONVECTION DUE TO SUBSIDENCE BEHIND THE SHORT WAVE IMPULSE LIKELY RESPONSIBLE FOR THE CURRENT CONVECTION. DIURNAL COOLING IN EARLY EVENING SHOULD ALLOW CELLS TO ABATE IN COVERAGE AND INTENSITY. LOWS OVERNIGHT LOW TO MIDDLE 70S EXPECTED WITH LOW-LEVEL WINDS STAYING UP A BIT OVERNIGHT. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...BERMUDA HIGH AND PIEDMONT TROUGH CONTINUE TO BE THE MAIN SURFACE FEATURES WHILE ALOFT WEAK LONGWAVE 5H TROUGH REPLACES FLAT RIDGING. MID LEVEL HEIGHT FALLS COMBINED WITH INCREASING LOW LEVEL THICKNESS LEADS TO AN INCREASE IN INSTABILITY DURING THE PERIOD. DEEP MOISTURE IN PLACE THU...PRECIPITABLE WATER VALUES APPROACH 2 INCHES...DECREASES A LITTLE FRI...PWATS DROP CLOSER TO 1.6 INCH IN THE AFTERNOON...AS MID LEVEL TROUGH AXIS SHIFTS EAST. BRIEF PERIOD OF DEEP WEST TO NORTHWEST FLOW FRI AFTERNOON AND EVENING WILL HELP LIMIT CONVECTION BUT STRENGTHENED PIEDMONT TROUGH MAY OFFSET THE WEAK MID LEVEL SUBSIDENCE. SEA BREEZE AND PIEDMONT TROUGH SHOULD BOTH BE ACTIVE EACH AFTERNOON WITH SEA BREEZE BEING HELD CLOSER TO THE COAST BY MORE WESTERLY FLOW...ESPECIALLY FRI. GIVEN THE LACK OF ANY SIGNIFICANT INTENSIFYING MID LEVEL FEATURES AND POTENTIAL FOR NUMEROUS OUTFLOWS DO NOT THINK COVERAGE CAN BE CONFINED TO ONE LOCATION. COASTAL AREAS ARE LIKELY FAVORED EARLIER IN THE DAY WITH HIGH POP SHIFTING INLAND LATER IN THE DAY AS PIEDMONT TROUGH ACTIVITY MOVES INTO THE REGION. HEAVY RAIN REMAINS A CONCERN...ESPECIALLY WITH TRAINING STORMS...BUT CANNOT RULE OUT A WET MICROBURST OR HAIL GIVEN THE COOLING MID LEVELS. TEMPERATURES WILL BE NEAR TO ABOVE CLIMO WITH HIGHS IN THE UPPER 80S TO LOWER 90S AND LOWS IN THE LOW TO MID 70S. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 3 PM WEDNESDAY...DEEP SOUTHERLY FLOW OF WARM AND MOIST AIR WILL CONTINUE THROUGH THE WEEKEND INTO NEXT WEEK AS LOCAL AREA REMAINS ON THE WESTERN PERIPHERY OF BERMUDA RIDGE AND EASTERN EDGE OF MID TO UPPER TROUGH TO OUR WEST. A MID TO UPPER LOW ROTATES AROUND THE GREAT LAKES AND DIGS DOWN THROUGH THE OHIO VALLEY INTO THE LOWER MISSISSIPPI VALLEY THROUGH THE WEEKEND INTO EARLY NEXT WEEK. MID TO UPPER LEVEL ENERGY WILL ROTATE AROUND THIS TROUGH UP THROUGH OUR LOCAL AREA PROVIDING ADDITIONAL SUPPORT TO ENHANCE CONVECTION OVER THE EASTERN CAROLINAS OVER THE WEEKEND INTO EARLY NEXT WEEK. BASICALLY WILL CONTINUE WITH WARM AND HUMID AIR MASS OVER THE AREA WITH PLENTY OF CLOUDS AND AND CHANCE OF SHWRS/TSTMS EACH DAY. PCP WATER VALUES REMAIN NEAR 2 INCHES OR GREATER THROUGH MOST OF THE PERIOD. MOISTURE PROFILES SHOW VERY DEEP MOISTURE WITH RH VALUES GREATER THAN 90% THROUGH MOST LEVELS ABOVE 10K FT. TEMPS WILL RUN NEAR OR ABOVE NORMAL THROUGH THE PERIOD WITH 70S FOR OVERNIGHT LOWS AND CLOSE TO 90 FOR AFTERNOON HIGHS. BY MID WEEK NEXT WEEK THE MID TO UPPER TROUGH OVER THE MID SECTIONS OF THE CONUS RETROGRADES AND WEAKENS ALLOWING FOR A STRONG RIDGE OVER THE ATLANTIC TO BUILD WESTWARD INTO THE AREA. THIS SHOULD PROVIDE DRYING THROUGH THE MID TO UPPER LEVELS AND INCREASED SUBSIDENCE LEADING TO DRIER WEATHER BY WED OR THURS TIME FRAME. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... AS OF 17Z...WATER VAPOR IMAGERY SHOWS AN UPPER IMPULSE APPROACHING OUR SOUTHERN TERMS...AND SOME WEAK CONVECTION HAS ALREADY DEVELOPED WEST OF OUR CWA THIS MORNING. HAVE INCLUDED VCTS FOR ALL TERMS THIS AFTN AS ISO STORMS ARE EXPECTED TO FIRE ALONG THE DEVELOPING SEA BREEZE SHORTLY. THE LATEST HRRR RUNS INDICATE THE WESTERLY STEERING FLOW MAY KEEP SEA BREEZE STORMS PINNED NEAR THE COAST. CONVECTION IS POSSIBLE INLAND AS WELL AS THE UPPER IMPULSE NEARS OUR WESTERN TERMS. EXPECT PREVAILING VFR AT ALL TERMS WITH BRIEF PERIODS OF MVFR/IFR IN +SHRA/TSRA...AND PERHAPS BETTER PCPN COVERAGE AT KFLO/KMYR/KCRE. CONVECTION SHOULD RAPIDLY DIMINISH AFTER 00Z. CANNOT RULE OUT POCKETS OF FOG/STRATUS OVERNIGHT...BUT GIVEN STRONG LOW-LEVEL WINDS AND LACK OF DEVELOPMENT THIS MORNING...CONFIDENCE IS LOW ATTM. AN APPROACHING SHORTWAVE/SFC TROUGH ON THURSDAY MAY BRING MORE WIDESPREAD SHOWERS/T-STORMS TO OUR AREA. EXTENDED OUTLOOK...ISO/SCT AFTERNOON SHOWERS AND T-STORMS THROUGH MONDAY WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM WEDNESDAY...SW FLOW TO PICK UP A BIT AS LOW PRESSURE INLAND DEEPENS A BIT...AND SW 15-20 KT IS EXPECTED REMAINDER OF THE AFTERNOON AND OVERNIGHT INTO EARLY THURSDAY. SEAS 3-4 FEET EXPECTED IN A MIX OF 3 FOOT SSW WAVES EVERY 5 SECONDS AND SE WAVES 1-2 FEET EVERY 8-9 SECONDS. TSTMS WILL BE POSSIBLE ON THE WATERS THROUGH DAYBREAK THURSDAY. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD AS WATERS REMAIN BETWEEN BERMUDA HIGH AND STRENGTHENING PIEDMONT TROUGH. WIND SPEEDS WILL INCREASE AS TROUGH BECOMES MORE DEFINED THU INTO FRI. WINDS INCREASE FROM 15 TO 20 KT THU TO A SOLID 20 KT FOR FRI. IN RESPONSE TO INCREASING WINDS SEAS WILL BUILD FROM 3 TO 5 FT ON THU TO 3 TO 6 FT LATE THU NIGHT THROUGH FRI NIGHT. HIGHEST SEAS WILL BE NEAR 20 NM AND IN AREAS OPEN TO EXTENDED SOUTHWEST FETCH...MAINLY IN AND AROUND FRYING PAN SHOALS. LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 3 PM WEDNESDAY...SOUTHERLY FLOW WILL CONTINUE AROUND WESTERN PERIPHERY OF BERMUDA HIGH THROUGH THE WEEKEND INTO EARLY NEXT WEEK. WINDS WILL GENERALLY BE 10 TO 15 KTS WITH A SPIKE UP EACH AFTN IN SEA BREEZE. PERSISTENT SOUTHERLY FLOW WILL KEEP SEAS UP AROUND 4 TO 6 FT THROUGH THE PERIOD. MAY END UP WITH AN EXTENDED PERIOD WITH A SMALL CRAFT ADVISORY FOR 6 FT SEAS IN STRONGER SOUTHERLY FLOW ESPECIALLY IN OUTER WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...COLBY SHORT TERM...III LONG TERM...RGZ AVIATION...BJR/COLBY
AREA FORECAST DISCUSSION...COR
NWS WILMINGTON NC
107 PM EDT WED JUN 26 2013 .SYNOPSIS... INCREASINGLY UNSETTLED WEATHER IS EXPECTED FOR THE REMAINDER OF THE WEEK INTO THE WEEKEND AS LOWER PRESSURE ALOFT DEEPENS OVER THE REGION. SHOWERS AND THUNDERSTORMS WILL FIRE EACH DAY ALONG AN INLAND SURFACE TROUGH...AS WELL AS THE SEA BREEZE. DAYTIME AND NIGHTTIME TEMPERATURES WILL HOLD CLOSE TO NORMAL FOR LATE JUNE TO EARLY JULY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 10 AM WEDNESDAY...STEERING FLOW TODAY WILL GUIDE CONVECTION TO THE E-ESE AROUND 15 MPH. SUBTLE SHORT-WAVE IMPULSES EXTENDING FROM WESTERN VA/NC INTO CENTRAL SC EVIDENT IN WATER VAPOR PICTURES FROM SPACE APPEARS TO BE AIDING MODERATELY STRONG CONVECTION PRESENTLY SOUTH OF COLUMBIA SC THIS MORNING...AND THIS WILL LIKELY STIR UP ACTIVITY OVER OUR W AND SW ZONES INTO THE LATE MORNING AND EARLY AFTERNOON. LATEST 12Z RAOB DATA SHOWS MINOR CAPS ALOFT AT 725MB 600MB AND 475MB...BUT THEY ARE WEAK AND SEE NO REASON WHY THESE SMALL BARRIERS CANNOT BE ERODED BY UPDRAFTS LATER TODAY. THIS MAY BE PARTICULARLY TRUE WITH PWAT VALUES AROUND 1.85 INCHES TODAY. THUS WE ALSO EXPECT CONVECTION TO FIRE ALONG THE INLAND MARCHING SEA-BREEZE FRONT DURING THE AFTERNOON. RADAR TRENDS AND WPC QPF DEPICTIONS POINT TO POTENTIALLY HEFTY RAINFALL AMOUNT FAVORED OVER WILLIAMSBURG AND GEORGETOWN COUNTIES SOUTHWARD INTO THE CHS FORECAST ZONES. FORTUNATELY THE STORM MOTION DOES NOT POSE AN OVERBEARING FLOOD THREAT...BUT GROUNDS DO REMAIN WET. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM WEDNESDAY... MID LEVEL TROUGHINESS DROPS INTO THE EASTERN U.S. ON THURSDAY. LOCAL STEERING FLOW TURNS TO THE WNW AND BL SWRLY FLOW INCREASES. SEA BREEZE NOT EXPECTED TO MAKE MUCH INLAND PROGRESS AND STORMS MAY FIRE JUST ABOUT ANYWHERE. SEABREEZE STORMS WILL BE ABLE TO AFFECT AREA BEACHES. SHORTWAVE PROGGED TO CROSS THE REGION DURING THE AFTERNOON AND EVENING WHICH MAY ENHANCE TSTM COVERAGE. PW REMAINS ABOVE 2 INCHES AND SO STORMS WILL YIELD HEAVY RAINFALL. STORM MOTION WILL BE NEARLY DOUBLE THAT OF DAYS PRIOR TO HOPEFULLY MITIGATE FLOODING POTENTIAL EXCEPT WHERE ANY TRAINING OCCURS. WET DOWNBURST HARD TO RULE OUT AS WELL SINCE MLCAPE MAY BE IN THE 1000-1500 J/KG RANGE ON THURSDAY AND POSSIBLY OVER 2000 J/KG ON FRIDAY. FRIDAY ALSO LOOKS QUITE ACTIVE WHILE NO APPRECIABLE SHORTWAVES APPEAR IN THE MODELS A WELL DEFINED PIEDMONT TROUGH WILL BE IN PLACE. ALTHOUGH THIS FEATURE WILL BE TO OUR WEST STORMS WILL ONCE AGAIN PROPAGATE EASTWARD. BETWEEN THOSE STORMS THAT GET WESTERN ZONES AND ANOTHER DAY OF AN ACTIVE SEABREEZE ITS HARD TO PICK OUT ANY FAVORED AREAS FOR TSTMS...MADE EVEN MORE TRUE BY THE NUMEROUS OUTFLOW BOUNDARIES THAT MAY LINGER FROM THURSDAY STORMS. TEMPERATURES WILL BE VERY NEAR CLIMO THROUGH THE PERIOD. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 AM WEDNESDAY...A COLD FRONT WILL LIE STALLED OVER THE WESTERN CAROLINAS FOR MOST OF THE PERIOD AS UPPER LEVEL PATTERN AMPLIFICATION HOLDS UP ANY EASTWARD PROGRESSION. RIDGES OVER WEST ATLANTIC AND JUST WEST OF THE ROCKIES WITH A TROUGH FROM GREAT LAKES TO LOWER MS. CAROLINA COASTS WILL REMAIN IN THE DEEP SSWRLY MOISTURE FLOW AHEAD OF THE BOUNDARY AND BE QUITE PRONE TO FAIRLY WIDESPREAD SHOWERS AND THUNDERSTORMS. AT THIS POINT ITS HARD TO TELL IF ANY GIVEN DAY OF THE EXTENDED HAS ANY HIGHER OR LOWER RAIN CHANCES THAN THE OTHERS. TEMPERATURES WILL BE VERY CLOSE TO CLIMO BUT INCREASING CLOUD COVER COULD TRIM A FEW DEGREES FROM HIGHS WHILE ADDING THE SAME TO LOWS. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 17Z...WATER VAPOR IMAGERY SHOWS AN UPPER IMPULSE APPROACHING OUR SOUTHERN TERMS...AND SOME WEAK CONVECTION HAS ALREADY DEVELOPED WEST OF OUR CWA THIS MORNING. HAVE INCLUDED VCTS FOR ALL TERMS THIS AFTN AS ISO STORMS ARE EXPECTED TO FIRE ALONG THE DEVELOPING SEA BREEZE SHORTLY. THE LATEST HRRR RUNS INDICATE THE WESTERLY STEERING FLOW MAY KEEP SEA BREEZE STORMS PINNED NEAR THE COAST. CONVECTION IS POSSIBLE INLAND AS WELL AS THE UPPER IMPULSE NEARS OUR WESTERN TERMS. EXPECT PREVAILING VFR AT ALL TERMS WITH BRIEF PERIODS OF MVFR/IFR IN +SHRA/TSRA...AND PERHAPS BETTER PCPN COVERAGE AT KFLO/KMYR/KCRE. CONVECTION SHOULD RAPIDLY DIMINISH AFTER 00Z. CANNOT RULE OUT POCKETS OF FOG/STRATUS OVERNIGHT...BUT GIVEN STRONG LOW-LEVEL WINDS AND LACK OF DEVELOPMENT THIS MORNING...CONFIDENCE IS LOW ATTM. AN APPROACHING SHORTWAVE/SFC TROUGH ON THURSDAY MAY BRING MORE WIDESPREAD SHOWERS/T-STORMS TO OUR AREA. EXTENDED OUTLOOK...ISO/SCT AFTERNOON SHOWERS AND T-STORMS THROUGH MONDAY WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 10 AM WEDNESDAY...SW WIND SPEEDS 15 KT EXPECTED TODAY. THE SEA BREEZE CIRCULATION WILL PUSH NEARSHORE WIND SPEEDS TO 15 TO 20 KT IN THE MID AFTERNOON THROUGH EARLY EVENING. SEA HEIGHTS WILL RUN 3 TO 4 FT...IN A MIX OF SSW WIND WAVES 2-3 FEET EVERY 5 SEC AND SE WAVES 1-2 FEET EVERY 8 SEC. A FEW TSTMS WILL BE POSSIBLE LATER THIS AFTERNOON INTO THIS EVENING...AS THE STEERING FLOW PUSHES TSTMS GENERALLY WEST TO E-ESE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 AM WEDNESDAY...PIEDMONT TROUGH DEVELOPS ON THURSDAY AND STRENGTHENS THURSDAY NIGHT. SWRLY GRADIENT WINDS TO INCREASE AND THE RESULTING SEAS COULD YIELD SMALL CRAFT ADVISORY FOR 6 FT SEAS OVER NRN ZONES. THE BOUNDARY WILL REMAIN TO OUR WEST INTO FRIDAY AND HIGH PRESSURE REMAINS ANCHORED ACROSS MUCH OF THE WEST ATLANTIC. LITTLE IF ANY CHANGES THUS EXPECTED IN WINDS AND SEAS. SOUTHERN ZONES MAY STAY CAPPED AT 5 FT SEAS AND SCEC MAY OR MAY NOT BE NEEDED...PERHAPS HINGING ON HOW MUCH SWELL ENERGY MAKES IT INTO THE FORECAST ZONES. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3 AM WEDNESDAY...THE WEEKEND LOOKS TO OFFER UNSETTLED CONDITIONS CONTINUING FROM THOSE OF THE SHORT TERM. SQUEEZE PLAY BETWEEN PIEDMONT TROUGH OVER LAND AND STRONG WEST ATLANTIC HIGH TO KEEP WIND AND SEAS AGITATED MORE THAN TYPICAL OF START OF JULY. NORTHERN ZONES PROBABLY LOOKING AT CONTINUATION OF LONG DURATION ADVISORY WHILE SOUTHERN ZONES CLOSER TO CUSP OF ADVISORY VS JUST SCEC HEADLINES. SOME 6FT SWELL ENERGY COULD MAKE IT INTO SC WATERS...ITS A LITTLE TOO EARLY TO TELL. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...COLBY SHORT TERM...BACON LONG TERM...MBB AVIATION...BJR/COLBY
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
225 PM CDT WED JUN 26 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 225 PM CDT WED JUN 26 2013 THIS EVENING...FORCING FROM APPROACHING SHORTWAVE CAN BE SEEN IN RADAR IMAGERY WITH WEAK RETURNS ACROSS CENTRAL NORTH DAKOTA. RAP/HRRR ALSO INDICATE A WEAK 925MB LOW THAT WOULD PROPAGATE FROM NW ND INTO SE ND THROUGH THE EVENING HOURS. LAPS ANALYSIS INDICATES MLCAPE 1000-2000 J/KG...AND DEEP LAYER SHEAR APPROACHING 50 KNOTS. THERE HAS BEEN SOME DRYING OF THE DEW POINTS ACROSS EASTERN NORTH DAKOTA...BUT THIS HAS HALTED AND VALUES HAVE RISEN A DEGREE OR TWO THE PAST HOUR. LOW LEVEL CONVERGENCE IS RATHER WEAK...WHICH WILL LIMIT AREAL COVERAGE. HOWEVER...THERE IS ENOUGH SUPPORT IN PLACE FOR AT LEAST A COUPLE STRONGER STORMS (MAIN THREAT LARGE HAIL AND STRONG WIND GUSTS). THURSDAY-THURSDAY NIGHT...UPPER RIDGE WILL BEGIN TO BUILD ACROSS THE WESTERN CONUS AND DEVELOP NORTHWEST FLOW ALOFT OVER THE REGION. COOL AIR ALOFT AND A WEAK MID-LEVEL TROUGH COULD LEAD TO AFTERNOON SHOWERS ACROSS NW MN. OTHERWISE...BREEZY AFTERNOON WINDS AND TEMPERATURES NEAR NORMAL. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 225 PM CDT WED JUN 26 2013 FRIDAY-SATURDAY...WESTERN CONUS RIDGE WILL CONTINUE TO BUILD AND DEVELOP MORE NORTHERLY FLOW ALOFT. A FEW SHORTWAVES WILL MOVE THROUGH THE REGION...BRINGING SCATTERED SHOWER CHANCES (AND PROBABLY THUNDER SINCE THERE WILL LIKELY BE SOME INSTABILITY). TEMPERATURES WILL BE A BIT COOLER. SATURDAY NIGHT-WEDNESDAY...THERE IS GENERAL AGREEMENT AMONG MODELS WITH AN AMPLIFYING MID/UPPER LEVEL RIDGE ACROSS THE WESTERN CONUS EARLY IN THE PERIOD...WITH NORTHWEST FLOW ALOFT ACROSS THE NORTHERN PLAINS. MAINLY DRY AND SEASONABLE CONDITIONS ARE EXPECTED FOR SUNDAY WITH WEAK SFC HIGH PRESSURE IN PLACE. BEYOND SUNDAY...THE PRIMARY CHALLENGE WILL BE CONVECTIVE CHANCES WITHIN THE NW FLOW PATTERN. MOST MODEL GUIDANCE SUGGESTS SOME EMBEDDED WAVES DROPPING SOUTH DURING THE MONDAY-WEDNESDAY PERIOD...WITH PERIODIC CHANCES FOR PRECIPITATION. THE 00Z ECMWF WAS A BIT FARTHER EAST WITH THE RIDGE AXIS...WHICH WOULD RESULT IN A DRIER PATTERN OVER THE AREA. THUS...KEPT SLIGHT/CHANCE ALLBLEND POPS GOING AS MODEL UNCERTAINTY INCREASES LATER IN THE PERIOD. TEMPERATURES ARE EXPECTED TO REMAIN FAIRLY SEASONABLE THROUGH THE PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1255 PM CDT WED JUN 26 2013 SCT TO BKN MAINLY VFR CU FIELD WILL CONTINUE THROUGH THE AFTERNOON...WITH CIGS OCCASIONALLY DROPPING INTO THE MVFR RANGE ESPECIALLY EAST OF THE VALLEY. DID UTILIZE 15Z HRRR TO INCLUDE MOST PROBABLE TIME PERIOD FOR CONVECTIVE ACTIVITY WITH THE PASSAGE OF A SFC TROUGH THIS AFTERNOON/EVENING. WITH SCATTERED NATURE OF ACTIVITY...WENT WITH VCTS FOR NOW. WEST WINDS THIS AFTERNOON WILL SUBSIDE THIS EVENING...BEFORE INCREASING AGAIN OUT OF THE WEST TO NORTHWEST BY MID TO LATE MORNING THURSDAY. && .HYDROLOGY... ISSUED AT 1255 PM CDT WED JUN 26 2013 ALL RIVERS AROUND FARGO ARE SEEING SHARP RISES AT THE PRESENT TIME. IT APPEARS THAT THE RED AT FARGO WILL APPROACH MAJOR FLOOD STAGE WITHIN THE NEXT COUPLE OF DAYS. SIMULATIONS INDICATE THAT POINTS DOWNSTREAM OF FARGO WILL ALSO APPROACH OR EXCEED MINOR FLOOD STAGE IN SEVERAL DAYS...FROM HALSTAD THROUGH OSLO MN. AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR WILKIN AND RICHLAND COUNTIES...AND A FLOOD ADVISORY HAS BEEN POSTED FOR CASS COUNTY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...TG LONG TERM...TG/MAKOWSKI AVIATION...MAKOWSKI HYDROLOGY...WJB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1255 PM CDT WED JUN 26 2013 .UPDATE... ISSUED AT 1255 PM CDT WED JUN 26 2013 MAIN CONCERN FOR TODAY WILL BE MARGINAL SEVERE THUNDERSTORM CHANCES. LAPS ANALYSIS INDICATES MLCAPE ALONG AND WEST OF THE VALLEY 1000-1500 J/KG...AND 500-1000 J/KG EAST OF THE VALLEY. THERE HAS NOT YET BEEN ENOUGH HEATING TO BREAK THE CAP...AND THINK WE SHOULD REMAIN DRY UNTIL AT LEAST MID-AFTERNOON. A BIT MORE HEATING COMBINED WITH FORCING FROM APPROACHING SHORTWAVE AND JET STREAK WILL LIKELY LEAD TO CONVECTIVE INITIATION. DEEP LAYER SHEAR INCREASES TO AROUND 50 KNOTS...WHICH COMBINED WITH THE INSTABILITY IN PLACE SHOULD LEAD TO A COUPLE STRONGER STORMS. EXPECTED COVERAGE NOT ENOUGH TO WARRANT A SLIGHT RISK FROM SPC...OR T+ IN THE GRIDS. PREVIOUS UPDATE APPEARS TO HANDLE THE SITUATION WELL. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 328 AM CDT WED JUN 26 2013 FOR THE REST OF TODAY...THE SURFACE LOW AND ASSOCIATED COLD FRONT WILL MOVE INTO THE MN ARROWHEAD. A SOMEWHAT DRIER AIR MASS WITH DEW POINTS IN THE UPPER 50S TO MID 60S WILL MOVE INTO THE REGION. SHOULD SEE DECREASING CLOUD COVER UNTIL THIS AFTERNOON WITH SOME THERMAL CU POSSIBLE GIVEN CONVECTIVE TEMPERATURES IN THE MID TO UPPER 80S. OUTSIDE OF THE NORTHEAST FORECAST AREA...WILL KEEP 20 POPS THROUGH THE DAY FOR A STRAY SHOWER OR THUNDERSTORM. TEMPERATURES SHOULD BE A TAD COOLER TODAY...ESPECIALLY ACROSS THE NORTHEAST...BUT WITH NO MAJOR CHANGE IN THE LOW LEVEL THERMAL PROFILE...AFTERNOON HIGHS WILL STILL REACH INTO THE MID TO UPPER 80S ALONG AND WEST OF THE VALLEY. SOME AFTERNOON SHOWERS AND THUNDERSTORMS ARE POSSIBLE IN THE LAKE OF THE WOODS REGION ON THURSDAY...BUT ALL OTHER AREAS SHOULD BE DRY WITH PARTLY SUNNY SKIES. IT WILL BE A BIT BREEZY FROM THE NORTHWEST WITH BOUNDARY LAYER WIND FROM 25 TO 30 KTS TO MIX TO THE SURFACE. HIGHS THURSDAY WILL BE FROM THE LOW TO MID 80S. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 328 AM CDT WED JUN 26 2013 500 HPA FLOW SHIFTS SHARPLY TO THE NORTHWEST BY FRIDAY WITH A SERIES OF WEAK SHORT-WAVES MOVING THROUGH THE NORTHERN PLAINS. WILL MAINTAIN 20 TO 40 POPS ACROSS THE NORTHEAST THIRD OF THE FORECAST AREA...BUT DO NOT ANTICIPATE WIDESPREAD RAINS. BREEZY NORTHWEST WIND WILL CONTINUE WITH HIGHS IN THE UPPER 70S TO LOWER 80S. NOT MUCH TIME SPENT ON EXTENDED (SAT-EARLY NEXT WEEK) DUE TO CURRENT FLOODING ISSUES. 00Z GFS/EURO SHOW UPPER LOW DROPPING INTO ERN ND/NW MN SATURDAY GIVING CHANCES FOR SOME PRECIPITATION...THEN EXITING SUNDAY. 00Z GEM IS DRIER. THEREAFTER..MODELS DIVERGE WITH EURO EXPANDING HEAT RIDGE OVER THE ROCKIES A BIT FARTHER EAST AND FORCING NEXT SHORT WAVE DUE MON-TUE A BIT FARTHER EAST OVER NORTHEAST MN. 00Z GFS IS FARTHER WEST WITH RIDGE AND HAS NEXT SHORT WAVE OVER OUR AREA MON-TUE AND HIGHER PRECIP CHANCES. KEPT WITH ALL BLEND IDEA OF HAVING 20-30 POPS EARLY NEXT WEEK FOLLOWING GFS SOLN. BUT CONFIDENCE IS QUITE LOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1255 PM CDT WED JUN 26 2013 SCT TO BKN MAINLY VFR CU FIELD WILL CONTINUE THROUGH THE AFTERNOON...WITH CIGS OCCASIONALLY DROPPING INTO THE MVFR RANGE ESPECIALLY EAST OF THE VALLEY. DID UTILIZE 15Z HRRR TO INCLUDE MOST PROBABLE TIME PERIOD FOR CONVECTIVE ACTIVITY WITH THE PASSAGE OF A SFC TROUGH THIS AFTERNOON/EVENING. WITH SCATTERED NATURE OF ACTIVITY...WENT WITH VCTS FOR NOW. WEST WINDS THIS AFTERNOON WILL SUBSIDE THIS EVENING...BEFORE INCREASING AGAIN OUT OF THE WEST TO NORTHWEST BY MID TO LATE MORNING THURSDAY. && .HYDROLOGY... ISSUED AT 1255 PM CDT WED JUN 26 2013 ALL RIVERS AROUND FARGO ARE SEEING SHARP RISES AT THE PRESENT TIME. IT APPEARS THAT THE RED AT FARGO WILL APPROACH MAJOR FLOOD STAGE WITHIN THE NEXT COUPLE OF DAYS. SIMULATIONS INDICATE THAT POINTS DOWNSTREAM OF FARGO WILL ALSO APPROACH OR EXCEED MINOR FLOOD STAGE IN SEVERAL DAYS...FROM HALSTAD THROUGH OSLO MN. AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR WILKIN AND RICHLAND COUNTIES...AND A FLOOD ADVISORY HAS BEEN POSTED FOR CASS COUNTY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...ROGERS LONG TERM...ROGERS/RIDDLE AVIATION...MAKOWSKI HYDROLOGY...WJB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1223 AM CDT WED JUN 26 2013 .UPDATE... ISSUED AT 1223 AM CDT WED JUN 26 2013 UPDATE FOR THE EXPIRATION OF SEVERE THUNDERSTORM WATCH 364 ACROSS THE JAMES RIVER VALLEY. REMAINING STORMS ACROSS DICKEY AND LAMOURE COUNTIES ARE EXPECTED TO CLEAR THE CWA BY 06 UTC AND REMAIN BELOW SEVERE LIMITS GIVEN WEAK DEEP LAYER SHEAR. WILL CONTINUE TO MONITOR RAINFALL WITH THESE STORMS. HOWEVER...THEY HAVE BEEN PROPAGATING TO THE EAST AT 20 KTS...LIMITING THE FLASH FLOOD THREAT. UPDATE ISSUED AT 1047 PM CDT TUE JUN 25 2013 SEVERE THUNDERSTORM WATCH HAS BEEN CANCELLED FOR ALL BUT FOSTER... STUTSMAN...DICKEY AND LAMOURE COUNTIES. HAVE ONCE AGAIN UPDATED FOR LATEST RADAR TRENDS...REMOVING ALL POPS BUT FOR THE REMAINING COUNTIES IN THE SEVERE THUNDERSTORM WATCH. THIS ACTIVITY SHOULD BE OUT OF THE CWA AROUND MIDNIGHT. WILL ALSO CANCEL THE REMAINING COUNTIES OF THE FLASH FLOOD WATCH SHORTLY. UPDATE ISSUED AT 849 PM CDT TUE JUN 25 2013 HAVE REMOVED ANOTHER TIER OF COUNTIES FROM THE SEVERE THUNDERSTORM AND FLASH FLOOD WATCHES. ALSO ADJUSTED POPS BASED ON CURRENT RADAR. OTHERWISE NO SIGNIFICANT CHANGES TO THE GOING FORECAST. UPDATED FLASH FLOOD WATCH AND WCN PRODUCTS HAVE BEEN SENT. REMAINING UPDATED PRODUCTS OUT SHORTLY. UPDATE ISSUED AT 708 PM CDT TUE JUN 25 2013 CONVECTION ACROSS CENTRAL NORTH DAKOTA CONTINUES TO MOVE NORTHEAST. WIND SHIFT HAS MOVED THROUGH NORTHWEST...INTO THE SOUTH CENTRAL PORTION OF THE STATE. THUS HAVE DROPPED WESTERN PORTIONS OF THE SEVERE THUNDERSTORM WATCH INCLUDING MORTON...MERCER... OLIVER...DIVIDE AND WILLIAMS. HAVE ALSO DROPPED WESTERN PORTIONS OF THE FLASH FLOOD WATCH. THESE UPDATES HAVE BEEN SENT. MAIN UPDATES WERE TO ADJUST POPS TO CURRENT RADAR TRENDS. UPDATED ZONES AND STATE WILL BE SENT SHORTLY. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 200 PM CDT TUE JUN 25 2013 FORECAST HIGHLIGHTS IN THE SHORT TERM FORECAST PERIOD WILL BE STRONG TO SEVERE THUNDERSTORMS AND HEAVY RAIN POTENTIAL THROUGH THIS EVENING. CURRENTLY...WARM AND VERY HUMID DAY WITH DAYTIME HIGHS IN THE 80S AND SURFACE DEWPOINT TEMPS FROM 60 TO THE LOW 70S. LATEST RADAR IS VOID OF ECHOS OVER WEST AND CENTRAL NORTH DAKOTA AS OF 2 PM CDT. LATEST MODEL GUIDANCE SUGGESTS CONVECTIVE DEVELOPMENT NORTHWEST/NORTH CENTRAL EARLY THIS AFTERNOON...BUILDING SOUTH- SOUTHEAST LATE AFTERNOON-EARLY EVENING ALONG A SURFACE TROUGH IN PLACE FROM NORTHWEST NORTH DAKOTA THROUGH CENTRAL SOUTH DAKOTA. 17-18Z RAP SOUNDINGS WEAKEN/ERASE THE CAP BETWEEN 20-22Z ALONG THE SFC TROUGH AXIS. TRIGGER WILL BE A STRONG MID LEVEL S/WV PUSHING INTO WESTERN NORTH DAKOTA NOW...HELPING TO WEAKEN THE STRONG CAPPING INVERSION CURRENTLY IN PLACE. CONVECTION SHOULD THEN PUSH EAST THIS EVENING INTO THE OVERNIGHT WITH THE MID LEVEL WAVE AND SFC TROUGH. STRONG TO SEVERE WEATHER REMAINS IN PLAY WITH THE VERY STRONG INSTABILITY PRESENT...CURRENTLY 3-6K J/KG. LIMITING FACTOR WILL BE RATHER WEAK 0-6KM/EFFECTIVE SHEAR UP TO AROUND 20KTS CURRENTLY IN PLACE AND FORECAST THROUGH THIS EVENING. STILL...WITH THE AMOUNT OF CAPE PRESENT THERE IS A GOOD PROBABILITY OF LARGE SEVERE HAIL AND A DAMAGING WIND GUSTS. STORMS WILL BE WATER LOADED SO WILL LIKELY NEED A RATHER ROBUST/TALL UPDRAFT TO GET THE LARGE HAIL. IT DOES APPEAR THE MAIN THREAT TODAY INTO THIS EVENING WILL BE VERY HEAVY RAINFALL ELEVATING THE THREAT FOR FLASH FLOODING. CONVECTIVE CHANCES WILL END FROM WEST TO EAST THIS EVENING THROUGH WEDNESDAY MORNING AS FORCING PUSHES EASTWARD. OPTED TO KEEP WEDNESDAY AFTERNOON DRY FOR NOW ALONG WITH THE 12Z GFS/00Z ECMWF. THE 06Z AND 12Z NAM BOTH PAINTED LIGHT DIURNALLY DRIVEN QPF...SO WILL LET LATER SHIFTS TAKE A LOOK WITH ATTENTION FOCUSED ON THE NEXT 12 HOURS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 200 PM CDT TUE JUN 25 2013 THE MAIN FEATURE FOR THE EXTENDED PERIOD WILL BE THE INTENSIFYING UPPER LEVEL RIDGE OVER THE WESTERN US/CANADA AS FORECAST BY THE 12Z MODEL SUITE. WITH THE RIDGE AXIS POSITIONED OVER THE INTERMOUNTAIN WEST...NORTH TO NORTHWESTERLY FLOW WILL BE DOMINANT ACROSS NORTH DAKOTA FOR MUCH OF THE PERIOD. THIS WILL ALLOW FOR SEASONABLE TEMPERATURES...IN THE 80S TO CONTINUE...KEEPING THE AREA OUT THE WARMEST H850 TEMPERATURES THAT WILL DEVELOP ACROSS THE WESTERN US. OVERALL THE FORECAST WILL REMAIN DRY...HOWEVER THERE WILL BE PERIODIC CHANCES FOR PRECIPITATION FOR PARTS OF CENTRAL AND EASTERN NORTH DAKOTA...AS A FEW SHORTWAVES ROTATE AROUND THE WESTERN PERIPHERY OF THE UPPER LEVEL LOW POSITIONED OVER THE GREAT LAKES REGION. LATE THIS WEEKEND/EARLY NEXT WEEK...SOME UNCERTAINTY IS INTRODUCED INTO THE FORECAST AS THE THERE IS SOME DISAGREEMENT AMONGST THE 12Z LONG RANGE MODELS REGARDING THE POTENT SHORTWAVE THAT IS PROGGED TO DROP SOUTH FROM CANADA AND INTO THE NORTHERN PLAINS. DUE TO THIS UNCERTAINTY...WILL MAKE NO CHANGES TO THE ALLBLEND SOLUTION AT THIS TIME SINCE THERE IS NO TARGET OF OPPORTUNITY TO IMPROVE FORECAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1223 AM CDT WED JUN 26 2013 VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS FOR THE 06 UTC TAF CYCLE SOUTH OF WEAK LOW PRESSURE ACROSS SOUTHERN CANADA. && .HYDROLOGY... ISSUED AT 200 PM CDT TUE JUN 25 2013 A FLASH FLOOD WATCH REMAINS IN EFFECT FOR NORTHWEST AND CENTRAL NORTH DAKOTA THROUGH THIS EVENING. VERY SLOW MOVING THUNDERSTORMS WITH INTENSE RAINFALL RATES ARE EXPECTED. ONE HOUR FLASH FLOOD GUIDANCE IS AROUND ONE TO ONE AND A HALF INCHES ACROSS MOST OF THE WATCH AREA. RAINFALL RATES WITH THUNDERSTORMS TODAY WILL EASILY SURPASS THIS THRESHOLD...AND WILL HAVE TO CLOSELY MONITOR FOR FLASH FLOODING THIS AFTERNOON AND EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AYD LONG TERM...LTH AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
734 PM EDT THU JUN 27 2013 .SYNOPSIS... UPPER LEVEL DROPS SOUTH ACROSS THE GREAT LAKES REGION INTO THE AREA FRIDAY THROUGH THE WEEKEND. IT MAY REGRESS TO THE WEST AFTER THAT. && .NEAR TERM /THROUGH FRIDAY/... UPDATE... NO LARGE SCALE CHANGES TO THE FORECAST. WILL NEED TO WATCH THE CONVECTION THIS EVENING...ESPECIALLY THAT UPSTREAM IN MICHIGAN AND NORTHERN OHIO WORKING TO THE SOUTH SOUTHEAST. EXPECT THIS TO WEAKEN AND DISSIPATE...ALTHOUGH THE HRRR DOES HOLD ONTO SOME REMNANTS COMING INTO THE NORTHERN ZONES AFTER 06Z. PREVIOUS DISCUSSION... THE UPPER LEVEL SHORTWAVE OVER PA...WILL CONTINUE TO MOVE EAST NORTHEAST LOOSING ITS INFLUENCE OVER WV. RADAR IMAGES SHOW THE BULK OF THE CONVECTION IS TO OVER THE NORTHEAST QUADRANT OF THIS SHORTWAVE. HOWEVER...LIGHT RAIN SHOWERS ARE EVIDENT ON RADAR...DEVELOPING IN THE WEST AND SOUTH QUADRANTS ACROSS OH...KY...TN...AND WV THIS AFTERNOON. EXPECT THESE LIGHT SHOWERS TO CONTINUE TONIGHT. THEREFORE...KEPT CHANCE POPS THROUGH FRIDAY MORNING. WITH NO REAL COLD AIR PUSHING MOISTURE AWAY...HIGH SFC DEWPOINTS...IN THE UPPER 60S WILL PERSIST THROUGH FRIDAY... BRINGING A MUGGY NIGHT...AND LOW CLOUDS OR AREAS OF FOG TONIGHT. BY FRIDAY AFTERNOON...A DEEP UPPER LEVEL TROUGH OVER CANADA DIGS SOUTH ACROSS THE GREAT LAKES REGION. THE GFS AND NAM80 SHOW H5 VORT MAXES PASSING ACROSS WV BY 00Z FRIDAY. WITH ABUNDANT MOISTURE AND A STRENGTHENING UPPER LOW OVERHEAD...EXPECT PLENTY OF CLOUDS AND LIKELY POPS ON FRIDAY WITH THIS SECOND SYSTEM. WENT CLOSER TO THE BIAS CORRECTED MAV NUMBERS PER HIGH DEWPOINTS AND PLENTY OF CLOUDS THROUGH THE PERIOD. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... AMPLIFIED UPR TROF BECOMING ESTABLISHED OVER THE REGION...WITH AXIS ACROSS OH VALLEY INTO MID MS VALLEY. HARD TO TIME IMPULSES WILL ROTATE DOWN THRU WEEKEND. CONT WITH THE DIURNAL NATURE TO POPS SOME BROAD HIGH CHC POPS FOR SAT. TEMPS TO COME DOWN TO MORE SEASONABLE LEVELS. && .LONG TERM /MONDAY THROUGH THURSDAY/... NOT MUCH CHANGE IN FCST REASONING IN THE EXTENDED FROM YESTERDAY. BERMUDA HIGH REMAINING IN PLACE AND TROF AXIS SLOWLY RETROGRADING TO MS VALLEY...UNSETTLED WX WILL BE THE RULE FOR THE WEEK. CONT WITH DIURNAL NATURE OF POPS WITH HIGH CHC EACH AFTN...WANING WITH AFTER SUNSET. BEST CONCENTRATION MAY END UP BEING ACROSS THE MTNS WITH SE LLVL FLOW PROVIDING FOR EXTRA LIFT. INFLUENCE OF BROAD DEEP S FLOW AND PWATS COMING UP TO ARND 1.75 INCHES TO ALLOW FOR DOWNPOURS. GENERALLY FOLLOWED HPC FOR TEMPS WITH TWEAKS HERE AND THERE. THIS ESSENTIALLY KEEPS THINGS STATUS QUO WITH SEASONAL HIGHS AND SOMEWHAT MUGGY NIGHTS. && .AVIATION /23Z THURSDAY THROUGH TUESDAY/... ISOLATED CONVECTION SHOULD DECREASE OVER THE NEXT FEW HOURS WITH THE END OF DAYTIME HEATING...AND KEEP ALL PREVAILING CONDITIONS FREE FROM SH OR TS. DO USE VCTS AND VCSH IN A COUPLE OF CASES. OTHERWISE...THE KEY TO THIS FORECAST IS THE WIND...WITH THE BULK OF THE GUIDANCE KEEPING THE WIND UP. ONLY THE MET GUIDANCE BRINGS CALM CONDITIONS LATER TONIGHT. RIDE THE MAJORITY VOTE HERE AND KEEP IFR MIST/FOG OUT OF THE FORECAST WITH WIND SPEEDS OF 4-6KTS SUSTAINED EXPECTED TONIGHT. THOSE TERMINALS STILL IN THE MVFR CEILINGS WILL SEE IMPROVEMENTS OVER THE NEXT FEW HOURS AS WELL. CONVECTION POSSIBILITIES RETURN FRIDAY DURING THE AFTERNOON HOURS...AS WILL WINDS GUSTING 15-20KTS. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY. MET GUIDANCE MAY HOLD THE KEY TO THE WINDS OVERNIGHT AND SUBSEQUENT FOG POTENTIAL. 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 L L L H M M M M M H H H HTS CONSISTENCY H M M M M M M M H H H H BKW CONSISTENCY L L L L L L M M M M M M EKN CONSISTENCY H H H H M L M L L L L L PKB CONSISTENCY H H M M M M M M M H H H CKB CONSISTENCY H H H H L L M H H H H H AFTER 00Z SATURDAY... NO WIDESPREAD IFR EXPECTED AT THIS TIME. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/30 NEAR TERM...ARJ/26 SHORT TERM...30 LONG TERM...30 AVIATION...26
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
949 PM CDT THU JUN 27 2013 .UPDATE... THE THUNDERSTORM COMPLEX THAT EXTENDS FROM NORTHEASTERN KANSAS SOUTHWEST THROUGH CENTRAL OKLAHOMA WEST INTO THE TEXAS PANHANDLE CONTINUES TO MOVE SOUTHWARD THIS EVENING. A DECENT OUTFLOW BOUNDARY IS APPARENT ON THE RADAR LOOPS THIS EVENING AHEAD OF THIS COMPLEX. THE THUNDERSTORM COMPLEX IS EXPECTED TO WEAKEN LATER THIS EVENING AND DISSIPATE BEFORE CROSSING THE RED RIVER OVERNIGHT. THE 18Z TEXAS TECH WRF IS NOT REPRESENTATIVE OF WHAT IS CURRENTLY HAPPENING. THE 00Z RUN OF THE NAM WHICH SEEMS TO BE UNDER-DOING WHAT IS CURRENTLY OCCURRING...ALSO INDICATES THAT THE COMPLEX SHOULD DISSIPATE BEFORE REACHING THE RED RIVER. THE HIGH RESOLUTION RAPID REFRESH AND THE RAP INDICATE THAT THE PART OF THE SYSTEM THAT WOULD AFFECT US ON ITS CURRENT TRACK WILL ALSO DISSIPATE BEFORE REACHING NORTH TEXAS. SOME HIGH CLOUDS FROM THIS ACTIVITY SPREAD INTO NORTH TEXAS LATER TONIGHT. AS FAR AS TOMORROW IS CONCERNED. IT STILL APPEARS THAT WE WILL HAVE A PRETTY HOT DAY WITH SOUTHWESTERLY SURFACE WINDS AHEAD OF THE WEAK COLD FRONT. WACO MAY COME CLOSE TO THEIR RECORD HIGH FOR JUNE 28TH WHICH IS 106 DEGREES SET IN 1980. THE RECORD HIGH FOR DFW FOR TOMORROW IS AN UNATTAINABLE /WE HOPE/ 112 DEGREES WHICH ALSO OCCURRED IN 1980. 58 && .AVIATION... AS WEAK FRONT PUSHES INTO THE AREA TOMORROW...WINDS WILL VEER TO THE WSW. THE FRONT AND ACCOMPANYING NORTH WINDS WILL NOT REACH THE METROPLEX TAF SITES UNTIL LATE AFTERNOON. ALTHOUGH THERE IS LITTLE UPPER SUPPORT...THE LIFT ALONG THE FRONT MAY PRODUCE ISOLATED TSRA GIVEN THAT HIGH TEMPERATURES ARE EXPECTED TO BE IN THE TRIPLE DIGITS. AT THIS TIME TS PROBABILITIES LOOK TOO LOW TO MENTION...BUT MAY HAVE TO INCLUDE IN LATER TAFS IF THIS EVENING/S HI RES MODELS BECOME WETTER. AT WACO...WINDS WILL ALSO VEER BUT FRONT WILL NOT REACH THERE UNTIL AFTER THIS TAF/S VALID TIME. 84 && .PREV DISCUSSION... /ISSUED 343 PM CDT THU JUN 27 2013/ CHANGES ARE ON THE WAY FOR NORTH AND CENTRAL TEXAS BEGINNING TOMORROW. THROUGH THE WEEKEND...THE UPPER LEVEL RIDGE THAT HAS BEEN DOMINATING THE AREA WILL AMPLIFY OVER THE WESTERN CONUS WHILE AN UPPER LEVEL TROUGH DIGS DEEP OVER THE EASTERN HALF OF THE COUNTRY. THE INFLUENCE OF THE UPPER LEVEL RIDGE WILL GREATLY BE WEAKENED FROM THE DEEPENING TROUGH TO OUR EAST. OVERALL...THIS WILL RESULT IN COOLER TEMPERATURES AND SLIGHT CHANCES FOR RAIN OVER THE NEXT WEEK. EXPECT ANOTHER MOSTLY CLEAR AND WARM NIGHT TONIGHT WITH OVERNIGHT LOWS IN THE MID TO UPPER 70S...EXCEPT LOWER 80S IN THE DALLAS CITY AREA. FRIDAY IS EXPECTED TO BE AN OPPRESSIVELY HOT DAY ACROSS PART OF THE REGION DUE TO A COOL FRONT MOVING INTO THE AREA. THIS FRONT WILL BE THE FIRST OF TWO THAT INFLUENCES NORTH AND CENTRAL TEXAS THIS WEEKEND. SHARPLY WARMING TEMPERATURES ARE EXPECTED AHEAD OF TOMORROWS FRONT WITH TEMPERATURES SOARING BETWEEN 101-107 AHEAD OF THE FRONT. THE CHALLENGE IS THE SPEED AND TIMING OF THE FRONT. THE LOCATION OF THE FRONT WILL DETERMINE WHERE THE HOTTEST TEMPERATURES WILL OCCUR TOMORROW. MOST OF THE MODELS /INCLUDING SHORTER TERM HI-RES MODELS/ HAVE THE FRONT AROUND THE I-20 CORRIDOR ABOUT MID AFTERNOON TOMORROW. BASED ON THIS TIMING/LOCATION...KEPT HIGH TEMPERATURES NORTH OF I-20 IN THE MID TO UPPER 90S...CLOSE TO 100-101 NEAR THE I-20 CORRIDOR...AND THEN RANGING FROM 103-107 SOUTH OF THE I-20 CORRIDOR. IN ADDITION...ALSO INTRODUCED A MENTION OF ISOLATED THUNDERSTORMS OVER THE NORTHERN TWO-THIRDS OF THE REGION FRIDAY AFTERNOON AS SOME MODELS INDICATE ISOLATED CONVECTION MAY DEVELOP ALONG AND SLIGHTLY AHEAD OF THE FRONT. HOWEVER...FORECAST SOUNDINGS INDICATE THE LOWER LEVELS OF THE ATMOSPHERE WILL BE PRETTY DRY. THIS POINTS TO THE POTENTIAL FOR LOTS OF EVAPORATION/VIRGA FROM MID LEVEL CLOUDS/CONVECTION AND ALSO A THREAT FOR GUSTY WINDS WITH ANY CONVECTION THAT DOES MATERIALIZE. BEHIND TOMORROWS COOL FRONT...DRIER AIR WILL BEGIN TO FILTER INTO THE REGION WITH A BETTER PUSH OF DRY AIR ON SUNDAY BEHIND THE NEXT FRONT/REINFORCING FRONT. TEMPERATURES ON SATURDAY WILL STILL BE WARM RANGING FROM THE LOWER 90S IN THE NORTHEAST TO UPPER 90S/NEAR 100 DEGREES IN THE WEST AND SOUTHWEST. TEMPERATURES WILL FINALLY START TO DROP SATURDAY NIGHT AND THE REMAINDER OF THE FORECAST LOOKS TO BE GENERALLY BELOW NORMAL. THE LATEST SET OF MODEL RUNS INDICATE THAT THE AIR BEHIND SUNDAY/S FRONT WILL BE DRIER THAN PREVIOUS MODEL RUNS...WITH DEWPOINTS IN THE 50S AND LOWER 60S THROUGH AT LEAST MID WEEK. THIS WILL RESULT IN LOWER OVERNIGHT LOWS AND ALSO MORE PLEASANT DAYTIME HIGHS FOR THIS TIME OF YEAR. IN SUMMARY...OVERNIGHT LOWS WILL MOSTLY BE IN THE 60S AND OCCASIONALLY LOWER 70S...DAYTIME HIGHS WILL BE IN THE MID 80S TO LOWER 90S. IT IS ALSO GOING TO FEEL MUCH DRIER WITH LOWER HUMIDITY VALUES THANKS TO THE LOWER DEWPOINT TEMPERATURES. WHILE THERE ARE SOME CHANCES FOR RAIN THROUGH THE FORECAST PERIOD...THE BEST CHANCES FOR RAIN MAY ACTUALLY COME NEAR THE END OF THE FORECAST...NEAR THE JULY 4TH HOLIDAY. HAVE TAPERED BACK THE POPS FOR SATURDAY AS IT LOOKS LIKE THE RIDGE WILL HOLD STRONG OVER OUR WESTERN COUNTIES. THERE ARE STILL SLIGHT CHANCES FOR RAIN OVER THE REGION ON SUNDAY AS THE NEXT FRONT ARRIVES. WITH THE DRIER AIR EXPECTED BEHIND SUNDAY/S FRONT...RAIN CHANCES EARLY NEXT WEEK ARE SLIM BUT NOT COMPLETELY ZERO. WE WILL BE UNDER THE INFLUENCE OF NORTHERLY FLOW ALOFT BETWEEN THE UPPER TROUGH TO OUR EAST AND THE RIDGE TO OUR WEST. HOWEVER...IT/S DIFFICULT TO PIN POINT EXACTLY WHEN AND WHERE ISOLATED CONVECTION WILL OCCUR THIS PATTERN AND KEPT GHOST 10 POPS IN THE FORECAST. WE COULD HAVE ISOLATED AFTERNOON CONVECTION NEAR OR IN OUR FAR EASTERN ZONES...CLOSER TO THE UPPER LEVEL TROUGH. BY THE MIDDLE TO END OF NEXT WEEK...THE UPPER LEVEL TROUGH TO OUR EAST WILL EXPAND FARTHER WEST AND WE COULD SEE SOME DISTURBANCES CROSSING THE REGION. INTRODUCED 20 POPS FOR NOW ON WEDNESDAY AND THURSDAY OF NEXT WEEK. 82/JLD && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 78 102 76 98 72 / 0 10 5 10 10 WACO, TX 76 104 75 99 71 / 0 10 10 10 10 PARIS, TX 74 97 71 92 66 / 5 10 5 10 10 DENTON, TX 76 99 73 97 69 / 5 10 5 10 10 MCKINNEY, TX 75 99 72 96 69 / 0 10 5 10 10 DALLAS, TX 81 102 77 98 74 / 0 10 5 10 10 TERRELL, TX 76 101 74 96 70 / 0 10 5 10 10 CORSICANA, TX 76 105 75 98 71 / 0 10 10 10 10 TEMPLE, TX 74 103 75 99 71 / 0 10 10 10 10 MINERAL WELLS, TX 77 103 73 98 69 / 0 10 5 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 84/58
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1049 PM CDT THU JUN 27 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 902 PM CDT THU JUN 27 2013 HAVE UPDATED PCPN TRENDS FOR THE REST OF THE NIGHT. ALTHOUGH THE CONVECTION HAS WEAKENED...POCKETS OF HEAVY RAINFALL WILL CONTINUE FOR AT LEAST A FEW MORE HOURS. FOR THE OVERNIGHT PERIOD...EXPECT SCT SHRA/ISOLD TSTMS...AS S/W TROFS CONTINUE TO SLIDE SE INTO THE FCST AREA. POPS WILL CONTINUE TO BE LOWEST OVER CENTRAL WI... ALTHOUGH ISOLD CONVECTION STILL LOOKS PSBL THERE. && .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 331 PM CDT THU JUN 27 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 100KT JET STREAK DIVING INTO THE WESTERN GREAT LAKES AS THE SOUTHWEST SUB- TROPICAL RIDGE BUILDS NORTHWARD. VARIOUS SHORTWAVE IMPULSES FROM SOUTHERN MANITOBA TO THE UPPER PENINSULA COMBINED WITH INCREASING INSTABILITY AROUND 1500 J/KG ARE TRIGGERING SCATTER SHOWERS AND THUNDERSTORMS. MANY STORMS HAVE BEEN FLIRTING WITH SEVERE LEVELS...WHICH SHOULD CONTINUE THROUGH EARLY THIS EVENING. PRIMARY UPPER TROUGH OVER SOUTHEAST MANITOBA WILL BE DROPPING INTO THE REGION TOMORROW. THE MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE WEATHER FOR THE REST OF TODAY AND PRECIP TOMORROW. TONIGHT...CHANNELED VORTS ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET WILL BE DIVING SOUTHEAST THIS EVENING ACROSS NORTHERN WISCONSIN. AMPLE INSTABILITY AROUND 1.5K J/KG COMBINED WITH THIS FORCING ALOFT SHOULD BE ABLE TO SUSTAIN STORMS INTO EASTERN WISCONSIN LATER THIS AFTERNOON AND THIS EVENING. AS THE JET STREAK SHIFTS A LITTLE SOUTH AND THE UPPER LOW MOVES OVER LAKE SUPERIOR...0-6KM BULK SHEAR VALUES WILL BE DROPPING THIS EVENING. COMBINED WITH LOSS OF INSTABILITY...SHOULD SEE STORMS DIMINISH IN INTENSITY BY MID EVENING. STILL SOME SHOWERS COULD POP UP THROUGH THE NIGHT OVER NORTH-CENTRAL TO NORTH-EAST WISCONSIN AND WILL LEAVE SMALL POPS IN THE FORECAST FOR THE REST OF THE NIGHT. LOWS IN THE 50S AND 60S. FRIDAY...THE UPPER LOW OVER LAKE SUPERIOR WILL DROP SOUTHEAST ACROSS THE CENTRAL GREAT LAKES. AS THIS OCCURS...A DEEP TROUGH WILL DROP ACROSS THE STATE WHICH SHOULD BRING SHOWERS AND STORMS TO NORTHERN WISCONSIN DURING THE MORNING. ADDITIONAL STORMS ARE LIKELY IN THE AFTERNOON WITH HELP FROM DIURNAL INSTABILITY. WITH THE CLOUD COVER AND COOLER TEMPS...NOT ANTICIPATING ANY SEVERE STORMS AT THIS TIME. A MOSTLY CLOUDY DAY WITH HIGHS IN THE UPPER 60S TO MID 70S. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 331 PM CDT THU JUN 27 2013 FOR THE EARLY PORTION OR THROUGH SATURDAY...CONVECTION WILL MAINLY BE ASSOCIATED WITH THE SOUTHWARD PASSAGE OF THE TROUGH AXIS. PCPN WILL BE ON THE DECREASE FROM NORTH TO SOUTH ON SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH. COOLER DRIER AIR WILL FILTER INTO THE STATE ON NORTH WINDS AS A LARGE HIGH PRESSURE SYSTEM SETTLES INTO THE NORTHERN PLAINS AND GREAT LAKES REGION. PROBLEM OR CHALLENGE WITH THE LATER PERIODS CONCERN ORIENTATION OF THE RETROGRADING DEEP UPPER TROUGH OR UPPER LOW OVER THE SURFACE HIGH PRESSURE. H5 TEMPS PROGGED TO BE ONLY IN THE -12 C RANGE ABOVE THE SURFACE HIGH...SO NOT REALLY A COOL AIR MASS ALOFT TO SUPPORT INSTABILITY AFTERNOON PCPN...SO WILL LEAVE THE SHOWER MENTION OUT OF THE LATER PERIODS FOR NOW...BUT CANNOT RULE OUT VERY ISOLATED SHOWER ACTIVITY. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1043 PM CDT THU JUN 27 2013 SEVERAL UPPER LEVEL DISTURBANCES WILL TRACK THROUGH THE AREA OVERNIGHT INTO FRIDAY...AND EACH WILL LIKELY RESULT IN SHRA/ISOLD TSRA DEVELOPMENT. PATCHY MVFR/IFR CONDITIONS ARE EXPECTED LATE TONIGHT...WITH FOG AND ISOLD TSTMS. MORE WIDESPREAD MVFR CIGS ARE EXPECTED TO DEVELOP ACROSS THE FORECAST AREA ON FRIDAY...AND SCT TSTMS ARE EXPECTED DURING THE AFTERNOON. COOLER NORTH WINDS AND ABUNDANT LOW-LEVEL MOISTURE MAY RESULT IN SOME IFR CIGS BY MID TO LATE FRIDAY EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........KIECKBUSCH SHORT TERM.....MPC LONG TERM......TDH AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
906 PM CDT THU JUN 27 2013 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 902 PM CDT THU JUN 27 2013 HAVE UPDATED PCPN TRENDS FOR THE REST OF THE NIGHT. ALTHOUGH THE CONVECTION HAS WEAKENED...POCKETS OF HEAVY RAINFALL WILL CONTINUE FOR AT LEAST A FEW MORE HOURS. FOR THE OVERNIGHT PERIOD...EXPECT SCT SHRA/ISOLD TSTMS...AS S/W TROFS CONTINUE TO SLIDE SE INTO THE FCST AREA. POPS WILL CONTINUE TO BE LOWEST OVER CENTRAL WI... ALTHOUGH ISOLD CONVECTION STILL LOOKS PSBL THERE. && .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 331 PM CDT THU JUN 27 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 100KT JET STREAK DIVING INTO THE WESTERN GREAT LAKES AS THE SOUTHWEST SUB- TROPICAL RIDGE BUILDS NORTHWARD. VARIOUS SHORTWAVE IMPULSES FROM SOUTHERN MANITOBA TO THE UPPER PENINSULA COMBINED WITH INCREASING INSTABILITY AROUND 1500 J/KG ARE TRIGGERING SCATTER SHOWERS AND THUNDERSTORMS. MANY STORMS HAVE BEEN FLIRTING WITH SEVERE LEVELS...WHICH SHOULD CONTINUE THROUGH EARLY THIS EVENING. PRIMARY UPPER TROUGH OVER SOUTHEAST MANITOBA WILL BE DROPPING INTO THE REGION TOMORROW. THE MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE WEATHER FOR THE REST OF TODAY AND PRECIP TOMORROW. TONIGHT...CHANNELED VORTS ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET WILL BE DIVING SOUTHEAST THIS EVENING ACROSS NORTHERN WISCONSIN. AMPLE INSTABILITY AROUND 1.5K J/KG COMBINED WITH THIS FORCING ALOFT SHOULD BE ABLE TO SUSTAIN STORMS INTO EASTERN WISCONSIN LATER THIS AFTERNOON AND THIS EVENING. AS THE JET STREAK SHIFTS A LITTLE SOUTH AND THE UPPER LOW MOVES OVER LAKE SUPERIOR...0-6KM BULK SHEAR VALUES WILL BE DROPPING THIS EVENING. COMBINED WITH LOSS OF INSTABILITY...SHOULD SEE STORMS DIMINISH IN INTENSITY BY MID EVENING. STILL SOME SHOWERS COULD POP UP THROUGH THE NIGHT OVER NORTH-CENTRAL TO NORTH-EAST WISCONSIN AND WILL LEAVE SMALL POPS IN THE FORECAST FOR THE REST OF THE NIGHT. LOWS IN THE 50S AND 60S. FRIDAY...THE UPPER LOW OVER LAKE SUPERIOR WILL DROP SOUTHEAST ACROSS THE CENTRAL GREAT LAKES. AS THIS OCCURS...A DEEP TROUGH WILL DROP ACROSS THE STATE WHICH SHOULD BRING SHOWERS AND STORMS TO NORTHERN WISCONSIN DURING THE MORNING. ADDITIONAL STORMS ARE LIKELY IN THE AFTERNOON WITH HELP FROM DIURNAL INSTABILITY. WITH THE CLOUD COVER AND COOLER TEMPS...NOT ANTICIPATING ANY SEVERE STORMS AT THIS TIME. A MOSTLY CLOUDY DAY WITH HIGHS IN THE UPPER 60S TO MID 70S. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 331 PM CDT THU JUN 27 2013 FOR THE EARLY PORTION OR THROUGH SATURDAY...CONVECTION WILL MAINLY BE ASSOCIATED WITH THE SOUTHWARD PASSAGE OF THE TROUGH AXIS. PCPN WILL BE ON THE DECREASE FROM NORTH TO SOUTH ON SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH. COOLER DRIER AIR WILL FILTER INTO THE STATE ON NORTH WINDS AS A LARGE HIGH PRESSURE SYSTEM SETTLES INTO THE NORTHERN PLAINS AND GREAT LAKES REGION. PROBLEM OR CHALLENGE WITH THE LATER PERIODS CONCERN ORIENTATION OF THE RETROGRADING DEEP UPPER TROUGH OR UPPER LOW OVER THE SURFACE HIGH PRESSURE. H5 TEMPS PROGGED TO BE ONLY IN THE -12 C RANGE ABOVE THE SURFACE HIGH...SO NOT REALLY A COOL AIR MASS ALOFT TO SUPPORT INSTABILITY AFTERNOON PCPN...SO WILL LEAVE THE SHOWER MENTION OUT OF THE LATER PERIODS FOR NOW...BUT CANNOT RULE OUT VERY ISOLATED SHOWER ACTIVITY. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 645 PM CDT THU JUN 27 2013 SEVERAL UPPER LEVEL DISTURBANCES WILL TRACK THROUGH THE AREA TONIGHT INTO FRIDAY...AND EACH WILL LIKELY RESULT IN SHRA/TSRA DEVELOPMENT. THE MOST FAVORABLE PERIODS WILL BE EARLY TO MID EVENING TONIGHT...THEN AGAIN LATE MORNING INTO THE AFTERNOON ON FRIDAY. MVFR/IFR CONDITIONS MAY ACCOMPANY ANY TSTMS. SOME LOW CLOUDS MAY DROP INTO NORTHERN WI LATE TONIGHT...AND AFFECT THE RHI TAF SITE. MORE WIDESPREAD MVFR CIGS ARE EXPECTED TO DEVELOP ACROSS THE ENTIRE FORECAST AREA ON FRIDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........KIECKBUSCH SHORT TERM.....MPC LONG TERM......TDH AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
649 PM CDT THU JUN 27 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND FRIDAY ISSUED AT 331 PM CDT THU JUN 27 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 100KT JET STREAK DIVING INTO THE WESTERN GREAT LAKES AS THE SOUTHWEST SUB- TROPICAL RIDGE BUILDS NORTHWARD. VARIOUS SHORTWAVE IMPULSES FROM SOUTHERN MANITOBA TO THE UPPER PENINSULA COMBINED WITH INCREASING INSTABILITY AROUND 1500 J/KG ARE TRIGGERING SCATTER SHOWERS AND THUNDERSTORMS. MANY STORMS HAVE BEEN FLIRTING WITH SEVERE LEVELS...WHICH SHOULD CONTINUE THROUGH EARLY THIS EVENING. PRIMARY UPPER TROUGH OVER SOUTHEAST MANITOBA WILL BE DROPPING INTO THE REGION TOMORROW. THE MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE WEATHER FOR THE REST OF TODAY AND PRECIP TOMORROW. TONIGHT...CHANNELED VORTS ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET WILL BE DIVING SOUTHEAST THIS EVENING ACROSS NORTHERN WISCONSIN. AMPLE INSTABILITY AROUND 1.5K J/KG COMBINED WITH THIS FORCING ALOFT SHOULD BE ABLE TO SUSTAIN STORMS INTO EASTERN WISCONSIN LATER THIS AFTERNOON AND THIS EVENING. AS THE JET STREAK SHIFTS A LITTLE SOUTH AND THE UPPER LOW MOVES OVER LAKE SUPERIOR...0-6KM BULK SHEAR VALUES WILL BE DROPPING THIS EVENING. COMBINED WITH LOSS OF INSTABILITY...SHOULD SEE STORMS DIMINISH IN INTENSITY BY MID EVENING. STILL SOME SHOWERS COULD POP UP THROUGH THE NIGHT OVER NORTH-CENTRAL TO NORTH-EAST WISCONSIN AND WILL LEAVE SMALL POPS IN THE FORECAST FOR THE REST OF THE NIGHT. LOWS IN THE 50S AND 60S. FRIDAY...THE UPPER LOW OVER LAKE SUPERIOR WILL DROP SOUTHEAST ACROSS THE CENTRAL GREAT LAKES. AS THIS OCCURS...A DEEP TROUGH WILL DROP ACROSS THE STATE WHICH SHOULD BRING SHOWERS AND STORMS TO NORTHERN WISCONSIN DURING THE MORNING. ADDITIONAL STORMS ARE LIKELY IN THE AFTERNOON WITH HELP FROM DIURNAL INSTABILITY. WITH THE CLOUD COVER AND COOLER TEMPS...NOT ANTICIPATING ANY SEVERE STORMS AT THIS TIME. A MOSTLY CLOUDY DAY WITH HIGHS IN THE UPPER 60S TO MID 70S. .LONG TERM...FRIDAY NIGHT THROUGH THURSDAY ISSUED AT 331 PM CDT THU JUN 27 2013 FOR THE EARLY PORTION OR THROUGH SATURDAY...CONVECTION WILL MAINLY BE ASSOCIATED WITH THE SOUTHWARD PASSAGE OF THE TROUGH AXIS. PCPN WILL BE ON THE DECREASE FROM NORTH TO SOUTH ON SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTH. COOLER DRIER AIR WILL FILTER INTO THE STATE ON NORTH WINDS AS A LARGE HIGH PRESSURE SYSTEM SETTLES INTO THE NORTHERN PLAINS AND GREAT LAKES REGION. PROBLEM OR CHALLENGE WITH THE LATER PERIODS CONCERN ORIENTATION OF THE RETROGRADING DEEP UPPER TROUGH OR UPPER LOW OVER THE SURFACE HIGH PRESSURE. H5 TEMPS PROGGED TO BE ONLY IN THE -12 C RANGE ABOVE THE SURFACE HIGH...SO NOT REALLY A COOL AIR MASS ALOFT TO SUPPORT INSTABILITY AFTERNOON PCPN...SO WILL LEAVE THE SHOWER MENTION OUT OF THE LATER PERIODS FOR NOW...BUT CANNOT RULE OUT VERY ISOLATED SHOWER ACTIVITY. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 645 PM CDT THU JUN 27 2013 SEVERAL UPPER LEVEL DISTURBANCES WILL TRACK THROUGH THE AREA TONIGHT INTO FRIDAY...AND EACH WILL LIKELY RESULT IN SHRA/TSRA DEVELOPMENT. THE MOST FAVORABLE PERIODS WILL BE EARLY TO MID EVENING TONIGHT...THEN AGAIN LATE MORNING INTO THE AFTERNOON ON FRIDAY. MVFR/IFR CONDITIONS MAY ACCOMPANY ANY TSTMS. SOME LOW CLOUDS MAY DROP INTO NORTHERN WI LATE TONIGHT...AND AFFECT THE RHI TAF SITE. MORE WIDESPREAD MVFR CIGS ARE EXPECTED TO DEVELOP ACROSS THE ENTIRE FORECAST AREA ON FRIDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TDH AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
231 PM CDT WED JUN 26 2013 .SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT) ISSUED AT 231 PM CDT WED JUN 26 2013 SURFACE MAP THIS AFTERNOON HAS A COLD FRONT MOVING EAST ACROSS EASTERN MN/IA. RADAR SHOWING A BROKEN LINE OF THUNDERSTORMS //SOME FAIRLY INTENSE TO SEVERE AT TIMES// EXTENDING N-S ALONG THIS FRONTAL BOUNDARY. LITTLE 0-3KM BULK SHEAR NOTED SO MOST OF THESE STORMS ARE PULSE-TYPE IN NATURE WITH HIGHER-END RAP 0-1KM ML MUCAPE IN THE 3500-4200J/KG RANGE. THIS UNSTABLE AIR IS BEING PRODUCED BY TEMPERATURES ACROSS THE AREA IN THE 80-85 DEGREE RANGE AND DEW POINTS IN THE LOWER 70S. LOOK FOR THIS FRONT TO SLIP EAST INTO CENTRAL WI THIS EVENING... DRAGGING THE BULK OF THE SHOWERS/THUNDERSTORMS WITH IT. WITH PRECIPITABLE WATER VALUES STILL SITTING IN THE 1.5-1.8 INCH RANGE...ANY SHOWER/THUNDERSTORM EARLY THIS EVENING WILL BE CAPABLE OF TORRENTIAL DOWNPOURS WITH SOME LOCALIZED PONDING OF WATER POSSIBLE...ESPECIALLY ACROSS AREAS THAT RECEIVED PREVIOUS HEAVY RAIN AND HAVE ALREADY SATURATED SOILS. INTRODUCED A SLIGHT CHANCE OF SHOWER/THUNDERSTORMS MAINLY NORTH OF I-94 LATER OVERNIGHT//AFTER 09Z// AS A MID-LEVEL TROUGH AND LEFT EXIT REGION OF 75-100KT 300MB JET PUSHES INTO THIS AREA. MOST OF THIS ACTIVITY LOOKS ELEVATED/ACCAS TYPE IN NATURE. BUFKIT SHOWS DRYING IN THE LOWER LEVELS...SO NOT CONFIDENT ON HOW MUCH RAINFALL WILL ACTUALLY REACH THE SURFACE. THEREFORE...WILL KEEP POPS ON THE LOW SIDE FOR NOW. THIS MID-LEVEL WAVE CONTINUES TO MOVE ACROSS THE AREA ON THURSDAY FOR A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS...MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER. MAY HAVE TO WATCH THIS CONVECTION CLOSELY FOR SEVERE WIND/HAIL THREAT GIVEN STEEPER LAPSE RATES AND 0-6KM BULK SHEAR IN THE 35-45KT RANGE. THE GFS... WHICH IS THE DRIEST OF THE MODELS AS FAR AS DEWPOINTS...YIELDS 0-1KM MLCAPE IN THE 1000-1500J/KG RANGE. IN ADDITION...MAY HAVE SOME ADDED LIFT DUE TO THE LEFT EXIT REGION OF 75-100KT 300MB JET. OTHERWISE...LOOKING FOR A HIGH IN THE LOWER/MIDDLE 80S WITH DEW POINTS IN THE MIDDLE 60S. LOOK FOR THE MID-LEVEL WAVE TO EXIT EAST OF THE REGION BY LATE THURSDAY EVENING...END THE THUNDERSTORM THREAT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 231 PM CDT WED JUN 26 2013 ON FRIDAY...MODELS IN GOOD AGREEMENT IN SWINGING A MID-LEVEL TROUGH SOUTHWESTWARD INTO THE AREA FROM THE GREAT LAKES REGION. STEEPENING LAPSE RATES WITH ASSOCIATED COLDER CYCLONIC FLOW ALOFT EXPECTED TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS MAINLY EAST OF THE MISSISSIPPI RIVER. OTHERWISE...PLAN ON HIGHS COOLING SOMEWHAT INTO THE MID 70S TO AROUND 80 WITH FAIRLY BREEZY NORTHWEST WINDS IN THE 10-20 MPH RANGE. LOOK FOR COOLER CONDITIONS WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORM ACTIVITY TO CONTINUE FRIDAY NIGHT THROUGH SATURDAY AS THE MID-LEVEL TROUGH SWINGS SOUTH THROUGH THE AREA. HIGHS ON SATURDAY WILL ACTUALLY SLIP SLIGHTLY BELOW NORMAL LEVELS IN THE LOW-MID 70S. APPEARS SHOWERS WILL BE EXITING THE AREA COMPLETELY BY SATURDAY EVENING AS THE TROUGH SHIFTS SOUTHEAST TOWARD THE OHIO RIVER VALLEY AND RIDGING BUILDS IN FROM THE NORTHWEST. FOR SUNDAY THROUGH WEDNESDAY...PLAN ON COOLER/OVERALL DRIER CONDITIONS AS A MAJOR MID-LEVEL TROUGH ESTABLISHES ITSELF OVER THE CENTRAL CONUS WITH A HIGHLY AMPLIFIED RIDGE ACROSS THE WESTERN CONUS. EC REMAINS DRY DESPITE COOLER CYCLONIC FLOW AND THE GFS IS LIGHT AND SPOTTY WITH ITS QPF. LOOKS LIKE MAINLY SOME DAYTIME CUMULUS BUT REMAINING DRY. OTHERWISE...HIGHS ARE EXPECTED TO BE IN THE 75-80 DEGREE RANGE WITH OVERNIGHT LOWS MAINLY IN THE 50S...VERY PLEASANT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1230 PM CDT WED JUN 26 2013 A SFC THRU 700MB TROUGH AXIS WAS MOVING EAST ACROSS MN EARLY THIS AFTERNOON. AHEAD OF THIS TROUGH SOME SCT-BKN DECKS OF MVFR STRATO-CU HAD SPREAD ACROSS SOUTHEAST MN/WESTERN WI. THESE WILL SLOWLY RAISE WITH DIURNAL WARMING/MIXING THIS AFTERNOON...BUT PERSIST UNTIL THE TROUGH AXIS PASSES. A SCT-BKN LINE OF SHRA/TSRA IS EXPECTED TO DEVELOP ALONG THIS TROUGH AS IT MOVES ACROSS THE AREA...BUT SO FAR WEST OF THE FCST AREA IT HAS BEEN QUIET. WILL LEAVE TSRA MENTION IN TAFS THIS AFTERNOON AS VCTS/CB UNTIL CONVECTION STARTS TO DEVELOP. IF A LINE OF SHRA/TSRA DOES DEVELOP...PLAN ON AN UPDATE OR TWO FOR 1 TO 2 HRS OF TSRA AS THE LINE PUSHES EAST ACROSS THE TAF SITES. ONCE THE TROUGH PASSES...DRIER AIR WILL START TO SPREAD ACROSS THE AREA WITH THE LOWER LEVEL WIND FLOW BECOMING WEST AND NORTHWEST. ENOUGH GRADIENT WIND EXPECTED TONIGHT TO KEEP BR/FG TO A MINIMUM... THOUGH SOME SPOTTY BR/FG POSSIBLE IN THE MS/WI RIVER VALLEYS. ONLY MENTIONED A SHORT PERIOD OF BCFG AROUND SUNRISE AT KLSE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...RRS
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 225 PM CDT WED JUN 26 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ELONGATED SHORTWAVE TROUGH SPINNING OVER THE LAKE WINNIPEG REGION WHICH ALSO EXTENDS SOUTH INTO THE NORTHERN MISSISSIPPI VALLEY. ANOTHER SHORTWAVE IS SPINNING OVER NORTHERN ILLINOIS AND IS HEADING EAST...SO NOT MUCH IMPACT ACROSS OUR AREA. STORMS FIRED UP AROUND MIDDAY ALONG A SURFACE TROUGH OVER THE WI/MN BORDER WHERE ML CAPES ARE REACHING UP TO 2K J/KG. THE FIRST WARNING THIS AFTERNOON WAS JUST ISSUED A FEW MINUTES AGO...BUT STORMS ARE NOT SHOWING MUCH ORGANIZATION AND 0-6KM BULK SHEAR VALUES ARE RATHER POOR AT AROUND 20 KTS. WITH SUCH WEAK BULK SHEAR VALUES...THINKING PULSY SEVERE AT THIS TIME UNLESS STORMS CAN BECOME MORE ORGANIZED. A FEW SPOTTY SHOWERS TRIED TO DEVELOP OVER NORTH-CENTRAL AND FAR NORTHEAST WISCONSIN...BUT FIZZLED OUT. SEVERE WEATHER CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...LATEST TIMING HAS STORMS ARRIVING INTO NORTH-CENTRAL WISCONSIN AT AROUND 21Z AND PROGRESSING EAST TO NORTHEAST WISCONSIN BY 00-01Z BEFORE EXITING AFTER 04Z. WITH STORMS ARRIVING AT OR NEAR PEAK HEATING...SEVERE WEATHER HAS POTENTIAL TO REACH NORTHEAST WISCONSIN THOUGH CAPES ARE NOT NEARLY AS IMPRESSIVE OVER NORTHEAST AND EAST-CENTRAL WISCONSIN AS FURTHER WEST. WITH LOSS OF HEATING AND WEAKER INSTABILITY...THINK SEVERE THREAT OVER THE EASTERN PARTS OF THE STATE ARE VERY MARGINAL. BETTER CHANCES WILL BE OVER NORTH-CENTRAL WISCONSIN. ONCE THE STORMS DEPARTS/WEAKEN...RATHER JUICY AIRMASS WILL LINGER FOR THE REST OF THE NIGHT. AREAS THAT RECEIVED RAIN WILL BE PRIME CANDIDATES FOR DENSE FOG AND WILL ADD FOG TO THE FORECAST. LOWS MAINLY IN THE LOW TO MID 60S. THURSDAY...THE UPPER TROUGH OVER LAKE WINNIPEG WILL SLIDE SOUTHEAST INTO LAKE SUPERIOR. WILL HAVE SUPPORT IN THE FORM OF UPPER DIVERGENCE IN THE LEFT FRONT QUAD OF THE JET STREAK FOR MUCH OF THE DAY...SO CANNOT RULE OUT SPOTTY SHOWERS AND STORMS IN THE MORNING. BUT THINKING STORMS ARE LIKELY FOR MOST OF NORTH-CENTRAL AND NORTHEAST WISCONSIN IN THE AFTERNOON...ONCE UPWARDS OF 1500 J/KG OF ML CAPE CAN DEVELOP ACCORDING TO PROGGED SOUNDINGS. WITH DEEP MIXING AND 0-6KM BULK SHEAR AROUND 30KTS...THINK SEVERE WEATHER IS POSSIBLE TOMORROW AFTERNOON. DAMAGING WIND GUSTS AND LARGE HAIL WILL BE THE MAIN THREATS. SHOULD FEEL LESS HUMID OUT THERE THAN TODAY...BUT HIGHS SHOULD STILL REACH INTO THE LOW TO MID 80S. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 225 PM CDT WED JUN 26 2013 IN GENERAL...MAINLY DIURNAL CONVECTION ANTICIPATED WITH AS A SHORT WAVE CARVES OUT A DEEP UPPER TROUGH OVER THE GREAT LAKES THROUGH EARLY SATURDAY FOLLOWED WITH A TREND FOR DRIER AND COOLER AIR IN THE NORTH FLOW FOR THE REST OF THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK. DIURNAL CONVECTION TO BE ON THE DECREASE THURSDAY NIGHT IN THE WEAK CYCLONIC FLOW. WILL CONTINUE THE TREND OF MAINLY EVENING SHOWERS CHANCES FOR MOST LOCATIONS. OTHERWISE SHOWERS WITH ISOLATED STORMS TO BE ON THE INCREASE AGAIN FRIDAY AS THE COOLER UPPER TROUGH SLOWLY DRIFTS SOUTHWARD OVER THE GREAT LAKES REGION. AGAIN A DIURNAL DECREASE MAY OCCUR LATER FRIDAY EVENING...BUT SHOWER ACTIVITY NOT LIKELY TO END UNTIL THE TROUGH AXIS SHIFTS FAR ENOUGH SOUTH. THE ECMWF AND GFS WERE THE MOST PROGRESSIVE WITH THE TROUGH AND PCPN SOUTH OF THE AREA SATURDAY MORNING. THE NAM IS MUCH SLOWER WITH THE TROUGH PASSAGE AND HANGS ONTO PCPN THROUGH SATURDAY AFTERNOON. EVENTUALLY COOLER DRIER ON NORTHERLY WINDS WILL SWEEP SOUTH OVER THE WESTERN GREAT LAKES LATER SATURDAY THROUGH THE FIRST FEW DAYS OF THE NEXT WEEK AS THE CANADIAN SURFACE HIGH PRESSURE SETTLES IN. PCPN CHANCES BEGIN TO RETURN AFTER TUESDAY AS THE GFS PROG THIS DEEP TROUGH TO CUT OFF INTO AN UPPER LOW AND RETROGRADE BACK INTO WESTERN GREAT LAKES REGION. THE ECMWF HAS A SIMILAR SOLUTION BUT DROPS ANOTHER PIECE OF ENERGY INTO THE NORTHERN PLAINS IN THE NORTHWEST FLOW. RETURN FLOW TUESDAY INTO WEDNESDAY CONFINED TO THE ROCKIES AND NORTHERN PLAINS SO WILL KEEP POPS ON THE LOW SIDE. IN ADDITION...ANY CONVECTION WHICH CAN DEVELOP WILL LIKELY BE DIURNAL. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1238 PM CDT WED JUN 26 2013 SHOWERS AND THUNDERSTORMS OVER THE WI/MN BORDER WILL TRACK EAST TODAY AND INTO NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON. OTHER POP UP STORMS ARE POSSIBLE OVER CENTRAL WISCONSIN TOO...BUT WILL PROBABLY HAVE TO WAIT UNTIL THIS EVENING FOR STORMS TO REACH EASTERN WISCONSIN. POTENTIAL IS THERE FOR STRONG GUSTY WINDS AND HEAVY DOWNPOURS WITHIN ANY THUNDERSTORMS. STORMS WILL EXIT LATE TONIGHT...BUT THE MOIST AIRMASS WILL LINGER. WITH LIGHT WINDS...PATCHY DENSE FOG IS POSSIBLE LATE TONIGHT...ESPECIALLY WHERE IT RAINS. ONCE ANY FOG BURNS OFF BY MID-MORNING...MORE STORMS WILL BE POSSIBLE TOMORROW AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TDH AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS TAUNTON MA
446 AM EDT FRI JUN 28 2013 .SYNOPSIS... WARM AND MUGGY CONDITIONS WILL CONTINUE WITH HIT AND MISS SHOWERS AND THUNDERSTORMS INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 400 AM UPDATE...OVERALL FORECAST TREND REMAINS ON TRACK. HAVE UPDATED TO ACCOUNT FOR CURRENT SITUATION. APPEARS WARM FRONT IS DRAPED FROM PROVINCETOWN THOUGH HARTFORD CT. EXPECT THIS FRONT TO CONTINUE NORTHWARD AS LOW PRESSURE STRENGTHENS. WINDS GUSTS MAY INCREASE ACROSS THE WEST AS PRESSURE GRADIENT TIGHTENS...UP TO 25KTS. PER VWP...LLJ IS STILL PUSHING THROUGH AS 925 VWP SHOW AROUND 35-40 KTS. THE AXIS OF THE LLJ WILL TRANSITION MORE OVER THE CAPE AND ISLANDS OVER THE NEXT FEW HOURS. ISOLATED TO SCATTERED SHOWERS WILL STILL MOVE ACROSS THE REGION OVER THE NEXT SEVERAL HOURS. BEST REGION IS OVER THE NW PORTION OF THE REGION. TODAY... *** FLASH FLOOD WATCH IS IN EFFECT THROUGH THIS AFTERNOON. *** LOW PRESSURE SYSTEM WILL SLIDE NORTHWARD BY FRIDAY. THIS WILL PUSH THE WARM FRONT/BOUNDARY NORTHWARD INTO NH ALLOWING FOR GOOD SOUTHERLY FLOW ACROSS THE REGION. SCATTERED SHOWERS WILL CONTINUE ESP ACROSS THE NORTHWEST PORTION OF THE REGION THIS MORNING. A FEW EMBEDDED THUNDERSTORMS MAY OCCUR AS WELL. OTHERWISE BELIEVE OVERALL AREAL COVERAGE WILL BE DISSIPATING. LOW LEVEL JET WILL STILL BE ANCHORED ACROSS THE CAPE/EASTERN WATERS THROUGH THE DAY WHICH COULD MAKE THINGS A TAD BREEZY ACROSS THE CAPE AND ISLANDS. MODELS ARE SHOWING SOME DRYING IN THE MID-LEVELS BY LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS. MAIN QUESTION IS THE POTENTIAL FOR STRONG THUNDERSTORMS LATER TODAY. MODELS ARE INDICATING THAT CLOUD COVER WILL BREAK LATER ALLOWING FOR SOME DIURNAL HEATING AND EVENTUALLY SOME THUNDERSTORMS. THE HI-RES WRF AS WELL AS THE HRRR AND OTHER MESOSCALE MODELS ARE ALSO INDICATING THIS FEATURE. IF THIS DOES PLAY OUT BELIEVE THE REGION THAT HAS THE BEST POTENTIAL WILL BE ACROSS THE WORCESTER HILLS AND WEST. THIS REGION SHOWS THE BETTER INSTABILITY...UP TO 2000 J/KG COMBINED WITH BULK SHEAR VALUES AROUND 30KTS AND LAPSE RATES OF 6 C/KM. ALSO HAVE UPPER LEVEL SUPPORT AS THE EXIT REGION OF THE JET MOVES OVER SOUTHERN NEW ENGLAND. IF THUNDERSTORMS DO DEVELOP BELIEVE THAT GUSTY WINDS...HAIL AND HEAVY DOWNPOURS WILL BE THE MAIN THREATS. SPC HAS OUTLOOKED MOST OF THE REGION WITHIN THEIR DAY 1 OUTLOOK. WE HAVE ALSO BEEN PLACED IN A 2 PERCENT TORNADO PROBABILITY. BELIEVE THE POTENTIAL IS LOW ESP SINCE SURFACE WINDS WILL BE MORE OUT OF THE SOUTH RATHER THAN THE WSW ALTHOUGH IT IS SOMETHING FOR THE DAY SHIFT TO EVALUATE. TEMPERATURES WILL BE TRICKY AGAIN TODAY. WARM FRONT WILL LIFT NORTHWARD ALLOWING FOR WARM AND MOIST AIR INTO THE REGION. HOWEVER FOG AND CLOUDS WILL LIMIT TRUE DIABATIC HEATING. RIGHT NOW EXPECT TEMPS TO BE IN THE MID TO UPPER 70S. IF THE SUN DOES PEAK OUT THEN TEMPS MAY WARM INTO THE LOW 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... ANY ONGOING CONVECTION SHOULD DWINDLE DOWN DURING THE EVENING HOURS AS DIURNAL HEATING IS LOST. STILL LEFT SCATTERED SHOWERS IN THE FORECAST. OTHERWISE MAIN CONCERN WILL BE FOG FOR THE OVERNIGHT HOURS AS VERY HUMID AIRMASS IS STILL IN PLACE. MODELS ARE INDICATING ANOTHER SURGE OF PRECIP TO PUSH ACROSS THE CAPE AND ISLANDS AFTER MIDNIGHT FROM THE LLJ. && .LONG TERM /SATURDAY THROUGH THURSDAY/... OVERVIEW...NOT MUCH CHANGE IN THE OVERALL SYNOPTIC PATTERN WITH THE 28/00Z GUIDANCE. STILL DO NOT HAVE MUCH CONFIDENCE IN THE MESOSCALE DETAILS EVIDENT IN ANY PARTICULAR MODEL. WITH ABOVE AVERAGE AGREEMENT WITH RESPECT TO THE OVERALL SYNOPTIC EVOLUTION...DECIDED TO USE A CONSENSUS BLEND TO TREND THE EXISTING FORECAST. THIS SOLUTION WILL FEATURE STRONG RIDGES DEVELOPING OVER THE WESTERN USA AS WELL AS THE WESTERN ATLANTIC. A SHORTWAVE MOVING OVER THE GREAT LAKES INTO THE MISSISSIPPI VALLEY AND FORMS AN ANOMALOUSLY STRONG CUTOFF LOW OVER THAT AREA. THIS UPPER LOW EVENTUALLY EJECTS INTO THE /CANADIAN/ WESTERLIES DURING THE MIDDLE OF NEXT WEEK. THE DAILIES... SATURDAY... ANOTHER SHORTWAVE ROTATES AROUND A GREAT LAKES UPPER LOW AND CROSSES EASTERN NY/NEW ENGLAND. A SUPPORTING UPPER JET HAS ITS RIGHT ENTRANCE REGION OVER NEW ENGLAND. A COLD FRONT STALLS OVER OR NEAR THE REGION AND PROVIDES A FOCUS FOR LOW LEVEL CONVERGENCE. PLENTY OF MOISTURE AVAILABLE WITH PRECIPITABLE WATER VALUES BETWEEN 1.5 AND 2.0 INCHES...HIGHEST SOUTHEAST. WE WILL FEATURE HIGHER POPS. WE WILL ALSO MENTION LOCALLY HEAVY DOWNPOURS DUE TO THE HIGH MOISTURE CONTENT. SUNDAY THROUGH THURSDAY...NOT MUCH CHANGE IN THE UPPER PATTERN WITH CLOSED LOW TO THE WEST AND UPPER RIDGE TO THE EAST...AND A MOIST SOUTH FLOW CONTINUING TO SUPPLY HIGH MOISTURE CONTENT AIR. WE WILL CONTINUE TO FEATURE AT LEAST A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. BEFORE 12Z...HIGH CONFIDENCE ON TRENDS...MODERATE CONFIDENCE ON TIMING. SCATTERED SHOWERS AND ISOLATED THUNDER WILL CONTINUE TO MOVE ACROSS SNE. A MIXTURE OF IFR/LIFR IS EXPECTED THROUGH THE MORNING HOURS FROM LOW CLOUDS AND FOG. AFTER 12Z...MODERATE CONFIDENCE. IFR/LIFR CONDITIONS EARLY...IMPROVING TO MVFR/IFR EAST AND MVFR/PATCHY VFR WEST. OVERALL IMPROVEMENTS BY LATE MORNING WEST TO EAST. HOWEVER SHOWERS AND THUNDERSTORMS WILL DEVELOP DURING THE LATE MORNING AND AFTERNOON HOURS. THEREFORE MVFR OUT WEST IN ANY HEAVY THUNDERSTORM. TONIGHT...VFR/MVFR WILL SLOWLY DROP TO MVFR/IFR ACROSS THE REGION IS LOW CLOUDS AND FOG. BEST REGION FOR LOWEST CONDITIONS WILL BE ALONG THE SOUTH COAST. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. CONFIDENT IN OVERALL TRENDS HOWEVER LOW CONFIDENCE IN TIMING. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. CONFIDENT IN OVERALL TRENDS HOWEVER LOW CONFIDENCE IN TIMING. OUTLOOK...SATURDAY THROUGH TUESDAY... MODERATE CONFIDENCE. PLENTY OF SHOWERS/TSTMS THIS WEEKEND WITH PERIODS OF MVFR CIGS/VSBYS IN SHOWERS...SOME OF THEM QUITE HEAVY. THE VERY HUMID AIRMASS WILL ALSO PRODUCE AREAS OF FOG AT NIGHT AND EARLY MORNING WITH IFR CIGS/VSBYS IN ANY SUCH FOG. POTENTIAL FOR VSBYS NEAR 1/4 MILE AT TIMES. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH FRIDAY...HIGH CONFIDENCE. SHORT-TERM THROUGH FRIDAY NIGHT...HIGH CONFIDENCE. SCA STILL CONTINUES ACROSS THE WATERS. CONTINUED TO UNDERCUT WNA WAVE GUIDANCE BY ABOUT 10 PERCENT TO ACCOUNT FOR ITS SOUTHERLY BIAS. OTHERWISE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO IMPACT THE WATERS TODAY AND INTO TONIGHT. MAIN THREATS WILL BE LIGHTNING AND HEAVY DOWNPOURS IMPACTING VISIBILITIES. OUTLOOK...SATURDAY THROUGH TUESDAY... PERIODS OF SHOWERS/TSTMS/FOG EXPECTED WITH VERY HUMID AIR CONTINUING. THERE WILL BE POOR VSBYS AT TIMES...AND 1/4 MILE VSBYS IN FOG POSSIBLE EARLY EACH MORNING. SOUTH TO SOUTHWEST WINDS THROUGH THE PERIOD. WIND GUSTS MAY APPROACH 25 KNOTS AT TIMES SATURDAY...BUT BE PRIMARILY 20 KNOTS OR LESS. THE STEADY WIND DIRECTION WILL HELP BUILD SEAS WITH WAVE HEIGHTS OF 5 TO 10 FEET EXPECTED ACROSS THE OUTER COASTAL WATERS AND EXPOSED PORTIONS OF THE SOUTHERN SOUNDS SUCH AS RI SOUND AND POSSIBLY BLOCK ISLAND SOUND. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THESE ROUGH SEAS THROUGH MIDWEEK...ESPECIALLY ACROSS THE OUTER COASTAL WATERS. && .HYDROLOGY... FLASH FLOOD WATCH CONTINUES THROUGH TODAY. RADAR ESTIMATED RAINFALL RATES UP TO 6 IN PER HOUR WITHIN SOME OF THE STRONGER THUNDERSTORMS LAST NIGHT. FORTUNATELY THESE THUNDERSTORMS REMAINED PROGRESSIVE AND DID NOT LINGER OVER ANY ONE LOCATION FOR VERY LONG. THESE RAINFALL RATES DO INDICATE THE POTENTIAL FOR HEAVY RAINFALL WITHIN THIS SOUPY AIRMASS. WILL NEED TO ESPECIALLY WATCH REGIONS OF HIGHER TERRAIN WHERE UPSLOPE COULD ENHANCE THE RAINFALL AS WELL AS URBANIZED AREAS... WHERE CONVECTIVE HEAVY RAIN MAY LEAD TO URBAN FLASH FLOODING. && .CLIMATE... WITH THE POTENTIAL FOR HEAVY RAIN TONIGHT INTO FRIDAY WE WILL BE ADDING TO THE ALREADY HIGH MONTHLY TOTALS FOR RAIN. BELOW PLEASE FIND THE TOP 10 WETTEST JUNE RAINFALL TOTALS FOR EACH OF OUR FOUR CLIMATE SITES...THESE INCLUDE RAINFALL TOTALS FOR JUNE 2013 ENDING AT MIDNIGHT THE MORNING OF JUNE 27. BOSTON... 1. 13.20 INCHES IN 1982 2. 11.58 INCHES IN 1998 3. 10.09 INCHES IN 2006 4. 9.87 INCHES IN 2013 5. 9.13 INCHES IN 1931 6. 8.63 INCHES IN 1959 7. 8.05 INCHES IN 1922 8. 7.79 INCHES IN 1881 9. 7.74 INCHES IN 1986 10. 7.25 INCHES IN 1875 HARTFORD... 1. 13.60 INCHES IN 1982 2. 10.62 INCHES IN 2013 3. 9.66 INCHES IN 1972 4. 9.16 INCHES IN 2006 5. 8.08 INCHES IN 1937 6. 8.00 INCHES IN 1920 7. 7.79 INCHES IN 1948 8. 7.18 INCHES IN 1998 9. 6.92 INCHES IN 1922 10. 6.79 INCHES IN 1986 PROVIDENCE... 1. 11.08 INCHES IN 1982 2. 9.61 INCHES IN 1998 3. 9.39 INCHES IN 2013 4. 9.24 INCHES IN 2006 5. 7.21 INCHES IN 1938 6. 6.83 INCHES IN 1978 7. 6.80 INCHES IN 1920 8. 6.72 INCHES IN 2001 9. 6.58 INCHES IN 1922 10. 5.84 INCHES IN 1989 WORCESTER... 1. 12.17 INCHES IN 1982 2. 9.68 INCHES IN 1998 3. 9.55 INCHES IN 2013 4. 9.25 INCHES IN 1972 5. 8.31 INCHES IN 1922 6. 7.78 INCHES IN 1968 7. 7.44 INCHES IN 1903 8. 7.39 INCHES IN 1938 9. 7.21 INCHES IN 1986 10. 6.98 INCHES IN 1973 & 1935 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR CTZ002>004. MA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR MAZ002>021-026. NH...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR NHZ011-012-015. RI...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ235-237- 254>256. SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 6 PM EDT SATURDAY FOR ANZ250. && $$ SYNOPSIS...DUNTEN/BELK NEAR TERM...DUNTEN SHORT TERM...DUNTEN LONG TERM...BELK AVIATION...DUNTEN/BELK MARINE...DUNTEN/BELK HYDROLOGY...BELK CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
303 AM CDT FRI JUN 28 2013 .SYNOPSIS... ISSUED AT 300 AM CDT FRI JUN 28 2013 WATER VAPOR LOOPS SHOWED A BROAD UPPER TROUGH ACROSS THE GREAT LAKES WITH A CLOSED LOW ON THE NORTHERN TIP OF LAKE SUPERIOR. A STRONG SHORT WAVE/VORT MAX WAS LOCATED IN NORTHEAST MN. A FEW SHOWERS WERE NOTED IN CENTRAL WI. OTHERWISE CLEAR SKIES WERE ACROSS THE DVN CWA WHILE A LARGE MCS WAS COVERING SOUTHERN MO AHEAD OF A COLD FRONT. CURRENT TEMPERATURES IN THE DVN CWA RANGED FROM THE MID 60S TO LOWER 70S WITH DEWPOINTS IN THE UPPER 50S NW TO UPPER 60S SE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 300 AM CDT FRI JUN 28 2013 FORECAST FOCUS ON SHOWER CHANCES...CLOUD TRENDS AND TEMPERATURES. TODAY...OPERATIONAL MODELS SLIDE THE GREAT LAKES TROUGH SOUTHWARD INTO OUR REGION WITH THE RAP DEPICTING A STRONG VORT MAX MOVING FROM NORTHEAST MN INTO NORTHERN IL THIS AFTERNOON. WITH COOLING TEMPERATURES ALOFT COMBINED WITH DAYTIME HEATING INSTABILITY WILL INCREASE. HAVE CONFINED POPS TO THIS AFTERNOON AND ALSO ACROSS OUR NORTHEAST HALF CWA CLOSER TO THE TRACK OF THE VORT MAX. THE HRRR MESO MODEL DEPICTS THE POPCORN DESCRIPTION OF THE SCATTERED INSTABILITY SHOWERS (AND A FEW THUNDERSTORMS) QUITE WELL. THERE WILL BE PLENTY OF SUNSHINE FOR MOST OF THIS MORNING BUT CLOUDS WILL DEVELOP/FILL AS THE CONVECTIVE TEMPERATURE IS REACHED. MAXIMUM TEMPERATURES WILL RANGE FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH BUT HUMIDITY LEVELS WILL BE THANKFULLY LOWER COMPARED TO THE LAST FEW DAYS. TONIGHT...WITH THE UPPER TROUGH OVER THE AREA WILL CONTINUE WITH CHANCE POPS AS SKIES WILL BE MOSTLY CLOUDY OR BECOME MOSTLY CLOUDY. HOWEVER...WITH THE LOSS OF HEATING/BETTER INSTABILITY THE COVERAGE OF SHOWERS WILL DECREASE OVERNIGHT. MINIMUM TEMPERATURES SHOULD BE IN THE LOWER 60S AT MOST LOCATIONS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 300 AM CDT FRI JUN 28 2013 A DIGGING UPPER TROF OVER THE EASTERN U.S IS FORECAST TO CLOSE OFF OVER THE OHIO VALLEY BY LATE IN THE WEEKEND. THEN...MODELS ARE IN AGREEMENT THAT THE CLOSED LOW WILL RETROGRADE INTO THE MID MISSISSIPPI VALLEY EARLY IN THE WEEK AND REMAIN THERE...THEN GRADUALLY FILLING DURING THE LATTER HALF OF THE WEEK. THIS PATTERN WILL SUPPORT BELOW NORMAL TEMPERATURES THROUGH THE FORECAST PERIOD WITH HIGHS GENERALLY IN THE 70S TO AROUND 80 AND LOWS...ESPECIALLY EARLY IN THE WEEK...IN THE 50S. MOST DAYS WILL HAVE AT LEAST A LOW THREAT OF RAIN. HOWEVER...AS STATED IN THE PREVIOUS DISCUSSION...THE RAIN THREAT WILL BE LIMITED TO JUST A FEW HOURS EACH DAY. THE BETTER CHANCE OF RAIN DURING THE PERIOD WILL BE SATURDAY AS A SERIES OF S/WS DROP INTO THE DEVELOPING TROF TO OUR EAST. THE BETTER UPPER FORCING APPEARS TO BE JUST EAST OF THE FORECAST AREA...SO KEPT THE HIGHER CHANCE AND LIKELY POPS NEAR AND EAST OF THE MISSISSIPPI RIVER. THE RAIN THREAT WILL DIMINISH SATURDAY NIGHT AND SUNDAY AS DRIER LOW LEVEL AIR FILTERS IN FROM THE NORTH. THE DRY WEATHER SHOULD LAST THROUGH MONDAY THEN A LOW RAIN THREAT RETURNS MONDAY NIGHT THROUGH THE END OF THE WEEK AS THE UPPER LOW BACKS INTO THE REGION FROM THE EAST. THIS WILL SUPPORT MAINLY AFTERNOON ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS. SINCE ANY SHRA/TSRA ACTIVITY WILL PROBABLY BE TIED TO AFTERNOON HEATING...HAVE LIMITED THE POPS TO THE DAYTIME HOURS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 300 AM CDT FRI JUN 28 2013 CLEAR SKIES AND LIGHT WINDS WILL REMAIN OVER THE AREA INTO THIS MORNING. AN UPPER LEVEL DISTURBANCE PASSING THROUGH THE REGION WILL PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY THIS AFTERNOON. THIS IS MOST LIKELY TO IMPACT THE DBQ SITE AND A TEMPO GROUP HAS BEEN ADDED. CID AND MLI MAY ALSO SEE AFTERNOON THUNDERSTORMS...BUT CONFIDENCE THAT THESE SITES WILL BE DIRECTLY IMPACTED IS NOT HIGH ENOUGH TO GO BEYOND PROB30 WORDING. OTHERWISE...CONDITIONS WILL REMAIN VFR WITH WEST TO NORTHWEST WINDS INCREASING AND BECOMING GUSTY FROM 15 TO 25 KTS FROM LATE MORNING THROUGH THIS AFTERNOON. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...DLF AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
305 AM CDT FRI JUN 28 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 305 AM CDT FRI JUN 28 2013 THUNDERSTORMS CONTINUE TO MOVE SOUTHEAST ACROSS MISSOURI AND FAR SOUTHEAST KANSAS AT 07Z. A SURFACE HIGH WAS BUILDING INTO THE PLAINS FROM MONTANA. SURFACE DEW POINTS CONTINUED IN THE MID TO UPPER 60S ACROSS THE CWA THIS MORNING. LATEST SATELLITE WATER VAPOR LOOP HAD A MID LEVEL HIGH OVER THE WESTERN STATES AND ROCKIES WHILE A TROUGH WAS OVER THE GREAT LAKES. TODAY AND TONIGHT THE MID LEVEL HIGH WILL BUILD SLOWLY EASTWARD WHILE THE MID LEVEL TROUGH DEEPENS ACROSS THE EASTERN U.S.. THIS WILL KEEP THE CENTRAL PLAINS IN A NORTHWEST FLOW PATTERN ALOFT. THE WAVES MOVING THROUGH THE TROUGH WILL REMAIN WELL TO THE EAST. THE SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD INTO KANSAS TODAY AND TONIGHT. THIS WILL BRING LOWER HUMIDITY AS DRIER AIR FILTERS INTO NORTH CENTRAL AND NORTHEAST KANSAS. FORECAST SOUNDINGS SHOW THE WE SHOULD MIX DOWN FROM AROUND 800 MB THIS AFTERNOON. THIS WILL YIELD HIGHS IN THE MID 80S TO LOWER 90S WITH THE COOLER TEMPERATURES IN THE NORTHEAST CORNER. MOSTLY CLEAR SKIES EXPECTED TONIGHT AND WITH THE SURFACE HIGH BUILDING IN WILL SEE TEMPS COOL INTO THE LOWER TO MIDDLE 60S. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 305 AM CDT FRI JUN 28 2013 UPPER JET CORE WILL BE OVERHEAD FOR MUCH OF THE WEEKEND ON THE WESTERN QUADRANT OF THE OHIO VALLEY UPPER TROF. MODELS CONTINUE TO SUGGEST SOME LIGHT PRECIP COULD DEVELOP THIS FAR WEST BUT SOUNDINGS ARE NOT SUGGESTIVE OF MUCH IF ANY INSTABILITY AND MOISTURE IS RATHER LIMITED. AM CONFIDENT ENOUGH TO REMOVE PRECIP MENTION HERE. WEAK UPPER FORCING IS AGREED UPON FOR EASTERN AREAS LATE SUNDAY INTO SUNDAY NIGHT BUT THIS COMES INTO AN EVEN DRYER AND MORE STABLE ATMOSPHERE SO WILL KEEP THESE PERIODS DRY AS WELL. WINDS WILL BE ON THE BREEZY SIDE DURING MUCH OF THE DAYTIME HOURS AS MIXING DEPTHS REACH SEVERAL THOUSAND FEET WITH A DECENT HEIGHT GRADIENT IN PLACE. LOW LEVEL TRAJECTORIES CONTINUE TO VEER TO A NORTH THEN NORTHEAST FOR A STEADY COOL-DOWN...WITH HIGHS POSSIBLY NOT BREACHING 80 IN THE EAST ON SUNDAY. MID RANGE MODELS ARE VERY CONSISTENT WITH THE BLOCKING REGIME OVER THE 30N-50N LATITUDES SLOWLY BREAKING DOWN THROUGH THE WORK WEEK WITH BROAD UPPER TROFFING RETROGRADING INTO THE PLAINS BY WEDNESDAY. NEAR MOIST ADIABATIC LAPSE RATES ABOVE THE BOUNDARY LAYER AND LITTLE IF ANY FORCING SHOULD ANY PRECIP IN CHECK THROUGH AT LEAST TUESDAY NIGHT. BY THURSDAY LEE TROFFING DEVELOPS ENOUGH FOR RISING LOW LEVEL THETA VALUES AND A MORE FAVORABLE KINEMATIC SETUP FOR HIGH PLAINS CONVECTION TO PUSH INTO EASTERN KANSAS BUT PRECIP CHANCES STILL LOOK LOW AT THIS POINT. TEMPERATURES WILL SLOWLY MODIFY TO NEAR EARLY JULY NORMALS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1149 PM CDT THU JUN 27 2013 WITH CONVECTION MOVING TO THE SOUTHEAST OF THE TERMINALS AND WEAK SURFACE RIDGING EXPECTED TO BUILD INTO THE AREA...ANTICIPATE VFR CONDITIONS TO PREVAIL THROUGH FRIDAY WITH A NORTH AND NORTHWEST WIND. THE RAP AND NAM ARE HINTING AT SOME WEAK INSTABILITY DEVELOPING WITH NO CIN ACROSS EAST CENTRAL KS. IF THERE WERE ENOUGH LOW LEVEL CONVERGENCE...AND ISOLATED STORM MAY BE POSSIBLE. HOWEVER PREDICTABILITY IS TO LOW TO MENTION IN THE TAFS AT THIS TIME. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...53 LONG TERM...65 AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1149 PM CDT THU JUN 27 2013 .SHORT TERM...(THIS EVENING) ISSUED AT 1232 PM CDT THU JUN 27 2013 AT 18Z...AN OUTFLOW BOUNDARY EXTENDED FROM NEAR OTTAWA TO JUNCTION CITY TO WASHINGTON...AND HAD ALREADY MIXED OUT A BIT NEAR THE NEBRASKA BORDER AS EVIDENCED BY BEATRICE WINDS TURNING OUT OF THE SSE. THE COLD SIDE OF THE OUTFLOW HAD STABILIZED A BIT AT THE SURFACE BUT ELEVATED PARCELS REMAINED VERY UNSTABLE. MEANWHILE... THE WARM SIDE OF THE OUTFLOW WAS EXTREMELY UNSTABLE WITH DEWPOINTS IN THE MID 70S AND TEMPERATURES CLIMBING WELL INTO THE 90S. DEEP LAYER SHEAR IS SUFFICIENT FOR SUPERCELL STRUCTURES PARTICULARLY WHEN COMBINED WITH THE EXTREME INSTABILITY IN PLACE. A SOMEWHAT ORGANIZED AREA OF CONVECTION HAS BEEN STEADILY MOVING SSE ACROSS SOUTHEAST NEBRASKA AND HAS SHOWN SIGNS OF INCREASING ORGANIZATION AND DEVELOPMENT ON THE WESTERN FLANK WHERE THE INSTABILITY FEED IS MORE SUBSTANTIAL. FEEL THAT THE MOST LIKELY SCENARIO FOR THIS AFTERNOON AND EVENING IS FOR THE ACTIVITY IN SOUTHERN NEBRASKA TO FURTHER ORGANIZE... LIKELY DEVELOPING A FORWARD PROPAGATING COLD POOL WHILE ALSO MAINTAINING EMBEDDED SUPERCELL STRUCTURES. THIS SEEMS TO BE A RATHER FAVORABLE SETUP FOR A DAMAGING WIND EVENT...ESPECIALLY ANYWHERE ON THE WARM SIDE OF THE OUTFLOW BOUNDARY BUT PERHAPS EXTENDING INTO THE COOL SIDE OF THE OUTFLOW BY 100 MILES OR SO AS WELL. THE MAGNITUDE OF INSTABILITY ALONG WITH THE SHEAR PROFILE SUGGEST THE POTENTIAL FOR VERY LARGE HAIL...PERHAPS ACCOMPANIED BY VERY STRONG WINDS AT TIMES. TORNADO POTENTIAL IS NON-ZERO...BUT WOULD SEEM TO BE LIMITED TO AREAS WHERE THE STORMS INTERSECT THE REMNANT OUTFLOW BOUNDARY AND TO ANY ORGANIZED CELLS ON THE WEST END OF ANY BOW ECHO. WOULD ALSO NEED TO KEEP AN EYE ON ANY BOOKEND VORTEX THAT COULD DEVELOP IN A WELL ORGANIZED BOW ECHO. THE BOTTOM LINE IS THAT AN ORGANIZED SEVERE WEATHER THREAT IS EXPECTED THIS AFTERNOON WITH THE PRIMARY THREATS BEING A COMBINATION OF WINDS UP TO 80 MPH AND HAIL UP TO TENNIS BALL SIZE. DO EXPECT STORMS TO COME TO AN END BY LATE EVENING WITH MORE PLEASANT CONDITIONS EVENTUALLY SETTLING INTO THE AREA BEHIND AN INCOMING COLD FRONT. BARJENBRUCH .LONG TERM...(FRIDAY THROUGH THURSDAY) ISSUED AT 246 PM CDT THU JUN 27 2013 THE EXTENDED PERIOD OF THE FORECAST WILL BE MARKED BY A FAIRLY QUIET WEATHER PATTERN AND COOLER THAN NORMAL TEMPERATURES. ONCE TODAY`S STORM SYSTEM TRACKS SOUTHEAST OF THE AREA OVERNIGHT...THE MID LEVEL RIDGE OVER THE WESTERN U.S. WILL CONTINUE TO AMPLIFY AS THE MID LEVEL TROUGH OVER THE EASTERN U.S. DIGS FURTHER SOUTH ALONG THE ATLANTIC COASTLINE. THIS PATTERN WILL REMAIN ANCHORED OVER THE CONUS THROUGH THE WEEKEND INTO EARLY NEXT WEEK...KEEPING THE CENTRAL PLAINS IN NORTHWESTERLY FLOW. THIS NORTHWESTERLY FLOW WILL RESULT IN COOLER TEMPERATURES IN THE UPCOMING DAYS...WITH HIGHS IN THE UPPER 80S/LOWER 90S ON FRIDAY AND DROPPING SLIGHTLY BELOW THE SEASONAL NORMALS THIS WEEKEND WITH HIGHS GENERALLY IN THE LOWER TO MIDDLE 80S. WITH SURFACE HIGH PRESSURE BUILDING IN BEHIND THE EXITING SYSTEM...EXPECT DRY CONDITIONS FRIDAY...THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. BY MID WEEK...THE MID LEVEL TROUGH LOOKS TO RETROGRADE SOMEWHAT FURTHER WEST INTO THE NORTHERN AND CENTRAL PLAINS AS A WAVE OVER CANADA MERGES INTO THE TROUGH. THE UPPER LEVEL FLOW BECOMES A BIT MESSY BY MID TO LATE WEEK WITH THIS PATTERN CHANGE. AN AREA OF LOW PRESSURE LOOKS TO MOVE INTO WESTERN KANSAS WEDNESDAY INTO THURSDAY WITH AN ASSOCIATE BOUNDARY POTENTIALLY EXTENDING EASTWARD TOWARD THE FORECAST AREA. BETTER CHANCES FOR PRECIPITATION ENTER BACK INTO THE FORECAST TUESDAY NIGHT THROUGH THURSDAY WITH THIS APPROACHING SYSTEM. HOWEVER...DUE TO THE UNCERTAINTY IN THE EXACT TRACKING OF THIS SYSTEM...HAVE ONLY INCLUDED SLIGHT CHANCE POPS AT THIS TIME. AS WINDS SHIFT MORE TO THE SOUTH FROM THIS NEARBY SURFACE LOW...AFTERNOON HIGHS SHOULD START WARMING A BIT CLOSER TO THE SEASONAL NORMALS BY THURSDAY WITH HIGHS IN THE MIDDLE 80S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1149 PM CDT THU JUN 27 2013 WITH CONVECTION MOVING TO THE SOUTHEAST OF THE TERMINALS AND WEAK SURFACE RIDGING EXPECTED TO BUILD INTO THE AREA...ANTICIPATE VFR CONDITIONS TO PREVAIL THROUGH FRIDAY WITH A NORTH AND NORTHWEST WIND. THE RAP AND NAM ARE HINTING AT SOME WEAK INSTABILITY DEVELOPING WITH NO CIN ACROSS EAST CENTRAL KS. IF THERE WERE ENOUGH LOW LEVEL CONVERGENCE...AND ISOLATED STORM MAY BE POSSIBLE. HOWEVER PREDICTABILITY IS TO LOW TO MENTION IN THE TAFS AT THIS TIME. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...BARJENBRUCH LONG TERM...HENNECKE AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1107 PM CDT THU JUN 27 2013 ...MESOSCALE UPDATE... .MESOSCALE DISCUSSION... ISSUED AT 1107 PM CDT THU JUN 27 2013 AFTER PERCOLATING ACROSS THE GREATER TOPEKA AREA FOR THE BETTER PART OF 4 HOURS...SOMEWHAT DISORGANIZED CLUSTER OF CONVECTION IS FINALLY STARTING TO MAKE ITS WAY SOUTHEAST INTO THE SGF CWA. MUCH OF THIS CONVECTION HAS SEEMINGLY BEEN ROOTED JUST ABOVE THE BOUNDARY LAYER...ON TOP OF A REMNANT COLD POOL FROM THE EARLY EVENING MCS THAT AFFECTED MUCH OF KANSAS. THIS HAS LIKELY PREVENTED THE CONVECTION FROM BECOMING BETTER ORGANIZED INTO A FORWARD PROPAGATING MCS. AS WE HEAD INTO THE OVERNIGHT HOURS...ANY CONVECTION THAT CAN MOVE SOUTH INTO THE SGF CWA SHOULD HAVE AN OPPORTUNITY TO PRODUCE AT LEAST SCATTERED SEVERE WEATHER...AS THE AIRMASS FURTHER SOUTH IS FAR MORE FAVORABLE FOR SEVERE WEATHER (ESPECIALLY DAMAGING WIND GUSTS) THAN ACROSS NORTHERN MISSOURI/NORTHEASTERN KANSAS. PRIMARY THREAT REMAINS STRAIGHT LINE WIND GUSTS...WITH A SECONDARY THREAT OF A FEW SEVERE HAIL STONES. THE TORNADO THREAT REMAINS NEARLY ZERO. STORMS MAY CONTINUE TO PERCOLATE FOR A WHILE ONCE THEY MOVE INTO THE SGF CWA...THOUGH THE SEVERE THREAT SHOULD SLOWLY WANE WITH TIME...GIVEN A SLOWLY COOLING BOUNDARY LAYER. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 330 PM CDT THU JUN 27 2013 WARM AND HUMID CONDITIONS ARE OCCURRING ACROSS THE REGION THIS AFTERNOON. TEMPERATURES ARE GENERALLY IN THE LOWER TO MIDDLE 90S WITH HEAT INDEX VALUES IN THE 100 TO 109 RANGE...WITH THE HIGHEST READINGS OCCURRING ALONG AND SOUTHWEST OF AN OSCEOLA TO SPRINGFIELD TO ALTON MISSOURI LINE. THESE CONDITIONS WILL PERSIST THROUGH THE REMINDER OF THE AFTERNOON HOURS INTO EARLY THIS EVENING. WILL KEEP THE HEAT ADVISORY GOING AS IS UNTIL 8 PM FOR THESE LOCATIONS. AN OUTFLOW BOUNDARY THAT DEVELOPED WITH CONVECTION ACROSS NORTHERN MISSOURI THIS MORNING IS CURRENTLY PUSHING SOUTH ACROSS THE AREA THIS AFTERNOON. THE AREA REMAINS FAIRLY CAPPED DUE TO A WARM AIRMASS...AND VERY LITTLE DEVELOPMENT HAS OCCURRED ON THIS BOUNDARY. A FEW ISOLATED STORMS HAVE BEEN ABLE TO DEVELOP ACROSS CENTRAL MISSOURI AND MAY REMAIN POSSIBLE ACROSS THE EASTERN OZARKS THIS AFTERNOON AS THE OUTFLOW PUSHES SOUTH...THOUGH MOST LOCATIONS SHOULD REMAIN DRY. A SURFACE FRONT IS CURRENTLY LOCATED ACROSS NORTHERN AND WESTERN KANSAS THIS AFTERNOON AND STORMS ARE BEGINNING TO DEVELOP ON THIS BOUNDARY. THIS TREND WILL CONTINUE THIS AFTERNOON AND THESE STORMS WILL FORM INTO A LINE LATER THIS AFTERNOON AND WILL ACCELERATE TO THE SOUTHEAST TOWARDS THE AREA THIS EVENING...EXITING THE AREA OVERNIGHT. LOCATIONS WITH THE BETTER POTENTIAL TO BE AFFECTED BY THIS ACTIVITY WILL BE FARTHER TO THE WEST...GENERALLY ALONG AND WEST OF HIGHWAY 65. THERE ARE MORE QUESTIONS HOW FAR EAST OF HIGHWAY 65 THIS ACTIVITY CAN MAKE IT....THOUGH THUNDERSTORMS ARE STILL POSSIBLE EAST OF HIGHWAY 65 THIS EVENING INTO THE OVERNIGHT HOURS. THE FORCING ALONG THE FRONT/COLD POOL THAT DEVELOPS FROM THE STORMS ACROSS KANSAS SHOULD BE ENOUGH TO BREAK THE CAP ACROSS THE AREA AND WITH STRONG THETA-E DIFFERENCE AND A VERY UNSTABLE AIRMASS WILL RESULT IN A STRONG DAMAGING WIND RISK WITH WINDS IN EXCESS OF 70 TO 80 MPH LIKELY ALONG THIS LINE WITH THE BEST POTENTIAL FOR WINDS THAT STRONG BEING WEST OF INTERSTATE 49. THERE IS A HAIL RISK...BUT WITH THESE STORMS EXPECTED TO BE LINEAR IN NATURE THIS POTENTIAL IS MORE LIMITED WITH GENERALLY UP TO QUARTERS POSSIBLE. TIMING OF THIS AREA WILL GENERALLY BE BETWEEN 7 AND 10 PM ALONG AND WEST OF THE INTERSTATE 49 CORRIDOR AND BETWEEN 8 AND MIDNIGHT WEST OF HIGHWAY 65. THERE ARE MORE QUESTIONS IF THIS LINE OF STORMS CAN MAKE IT EAST OF HIGHWAY 65...AND WILL HAVE TO SEE EXACTLY WHERE THIS LINE SETS UP ACROSS KANSAS. FRIDAY SHOULD GENERALLY BE DRY...THOUGH AN ISOLATED AFTERNOON THUNDERSTORM MAY BE POSSIBLE IF ENOUGH INSTABILITY CAN DEVELOP... THOUGH THIS POTENTIAL LOOKS REALLY LIMITED. TEMPERATURES WILL BE COOLER ON FRIDAY THAN TODAY...BUT HIGHS WILL STILL TOP OUT IN THE UPPER 80S TO THE LOWER 90S. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 330 PM CDT THU JUN 27 2013 AN UPPER LEVEL LOW WILL BUILD SOUTHWEST OUT OF THE GREAT LAKES REGION OVER THE CENTRAL U.S. THIS WEEKEND THROUGH MUCH OF NEXT WEEK. THIS WILL PUSH THE UPPER LEVEL RIDGE AND HOT AND MUGGY CONDITIONS BACK TO THE WEST AND ALLOW A COOLER AIRMASS TO SPREAD INTO THE REGION. HIGHS THIS WEEKEND THROUGH NEXT WEEK WILL GENERALLY BE IN THE UPPER 70S TO THE MIDDLE 80S EACH AFTERNOON AS LOWS DROP INTO THE LOWER TO MIDDLE 60S EACH NIGHT. THERE COULD BE PERIODS OF SHOWERS AND THUNDERSTORMS AT TIMES AS THE UPPER LEVEL LOW REMAINS OVER THE REGION BUT NO SEVERE WEATHER OR WASH OUT IS EXPECTED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 630 PM CDT THU JUN 27 2013 STRONG/SEVERE CONVECTION CONTINUES TO FIRE ALONG A COLD FRONT TO THE WEST AND NORTHWEST OF THE CWA. IF THIS LINE CAN FILL IN BETWEEN SALINA AND KANSAS CITY...IT WILL LIKELY AFFECT THE TAF SITES THIS EVENING BETWEEN 02Z AND 04Z. IF IT DOESNT FILL IN...THE CURRENT CONVECTION TO THE WEST WILL LIKELY MISS OUR SITES TO THE WEST. HAVE CURRENTLY PUT IN A TEMPO GROUP...ROUGHLY USING THE LATEST HRRR AS TIMING GUIDANCE AFFECTING THE TAF SITES THIS EVENING. PRIOR TO AND AFTER THE CONVECTION...VFR CONDITIONS EXPECTED. DURING CONVECTION...GENERALLY MVFR CONDITIONS EXPECTED. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ MESOSCALE...BOXELL SHORT TERM...WISE LONG TERM...WISE AVIATION...LINDENBERG
AREA FORECAST DISCUSSION
NWS BUFFALO NY
501 AM EDT FRI JUN 28 2013 .SYNOPSIS... LOW PRESSURE WILL SLOWLY LIFT ACROSS EASTERN NEW YORK TODAY...WITH THIS LOW EXPECTED TO STALL NEAR THE REGION AS IT GRADUALLY WEAKENS THROUGH THE WEEKEND. THIS WILL BRING PERIODS OF RAIN TODAY...WITH EMBEDDED AREAS OF HEAVIER RAIN AND THUNDERSTORMS. THE THREAT FOR SHOWERS AND PERHAPS A THUNDERSTORM WILL PERSIST THROUGH THE WEEKEND...HOWEVER SHOWERS WILL BECOME INCREASINGLY SCATTERED AS THE WEEKEND WEARS ON. && .NEAR TERM /THROUGH TONIGHT/... THERE CONTINUES TO BE A POTENTIAL FOR FLOODING ACROSS PORTIONS OF WESTERN NEW YORK TODAY. THERE APPEARS TO BE TWO MAIN FEATURES TO WATCH TODAY...WITH THE MOST OBVIOUS BEING THE LARGE AREA OF RAIN ASSOCIATED WITH THE WEAK SURFACE LOW WHICH IS LIFTING ACROSS EASTERN NEW YORK STATE. RADAR TRENDS SUPPORT THE HRRR HANDLING OF THIS FEATURE...WHICH LARGELY KEEPS THE CORE OF IT TO THE SOUTH AND EAST OF OUR CWA. THIS SAID...EXPECT A RATHER QUICK INCH OF RAIN ACROSS LEWIS COUNTY THROUGH MID-MORNING...WITH LESSER AMOUNTS TO THE WEST IN JEFFERSON/OSWEGO COUNTIES. IF THIS HOLDS...WE PROBABLY WILL NOT SEE FLOODING...HOWEVER GIVEN THE CLOSE PROXIMITY OF HEAVIER RAINS WE WILL KEEP UP THE FLOOD WATCH. UPSTREAM RAINS WILL LIKELY CAUSE WITHIN BANK RISES ON THE BLACK RIVER AT BOONVILLE. THE SECOND FEATURE WE WILL BE KEEPING A CLOSE EYE ON IS A MORE SUBTLE UPPER LEVEL TROF AXIS WHICH EXTENDS FROM WESTERN NEW YORK BACK INTO SOUTHERN ONTARIO TO GEORGIAN BAY. SCATTERED...BUT VERY SLOW MOVING...SHOWERS ALONG THIS AXIS ARE FORECAST TO EXPAND BY THE HRRR. SEVERAL RUNS OF THE NAM/RGEM SUPPORT THE HRRR FORECAST...AND GIVEN A FAIRLY GOOD TRACK RECORD FOR THIS EVENT...HAVE MODERATE CONFIDENCE IN ITS FORECAST. EXPECT SHOWERS TO DEVELOP ALONG A NW-SE AXIS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AROUND DAYBREAK...WITH THIS AXIS LIKELY TO SLOWLY LIFT NORTH TO A BUFFALO TO WELLSVILLE LINE BY EARLY AFTERNOON...THEN EVENTUALLY FURTHER NORTH AND EAST BY LATE AFTERNOON. THIS PRECIPITATION WILL BE CONVECTIVE...WITH BUFKIT SHOWING A MOIST SOUNDING WITH THIN AND NARROW CAPES...AND P-WAT VALUES AROUND 1.6 INCHES. CONSENSUS QPFS FROM THE HIGHER RESOLUTION MODELS INCLUDING RECENT RUNS OF THE NAM/RGEM/SREF ONLY AVERAGE AROUND AN INCH WITH THIS. HOWEVER...GIVEN THE SLOW MOTION OF THE CONVECTIVE CELLS...LOCALLY HIGHER AMOUNTS ARE POSSIBLE. YESTERDAY EVENING SLOW MOVING SHOWERS RESULTED IN RADAR ESTIMATES OF OVER 3 INCHES IN A FEW SPOTS IN SOUTHERN ONTARIO PROVINCE. RAIN AMOUNTS IN EXCESS OF TWO INCHES WOULD BE A CONCERN PRETTY MUCH ANYWHERE...WITH URBAN AREAS...THE BUFFALO CREEKS...AND AREAS WITH RECENT RAINS VULNERABLE TO LESSER RAINFALL AMOUNTS. FOLLOWING THIS...WILL KEEP THE FLOOD WATCH UP IN WESTERN NEW YORK AS WELL. THE UPPER LOW WILL GRADUALLY MOVE ACROSS THE REGION TONIGHT...WHICH WILL EFFECTIVELY END THIS AXIS AS THE LOW BECOMES VERTICALLY STACKED. THERE WILL BE A LINGERING THREAT FOR SHOWERS TONIGHT...WITH SHOWERS EXPECTED TO BECOME INCREASINGLY SCATTERED IN NATURE AS THE NIGHT GOES ON. WHILE WIDESPREAD THUNDERSTORMS ARE NOT LIKELY...THERE MAY BE SOME EMBEDDED IN AREAS OF HEAVY RAIN TODAY. TEMPERATURES WILL NOT RISE VERY MUCH AT ALL TODAY...WITH PERSISTENT CLOUDS COVER AND AREAS OF SHOWERS. EXPECT HIGHS TO ONLY BE AROUND 70 DEGREES IN MOST LOCATIONS. OVERNIGHT LOWS SHOULD DROP INTO THE UPPER 50S TO LOWER 60S. PATCHY FOG IS LIKELY...AND WHILE MOSTLY CLOUDY SKIES ARE EXPECTED...ANY CLEARING WOULD QUICKLY FAIRLY DENSE FOG DEVELOPMENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A FULL LATITUDE TROUGH IS FORECAST TO REMAIN IN PLACE FROM SOUTHERN QUEBEC TO THE TENNESSEE VALLEY THROUGH THIS PERIOD. THE DEEP LAYERED SOUTHERLY FLOW WILL KEEP MOIST AND SOMEWHAT UNSTABLE AIR OVER OUR AREA WHICH WILL LEAD TO OCCASIONAL SHOWERS AND SCATTERED THUNDERSTORMS. THE MODELS AGREE THAT A LOW LEVEL TROUGH/BAROCLINIC ZONE WILL REMAIN STALLED OVER CENTRAL NEW YORK STATE. THIS BOUNDARY WILL HELP TO FOCUS THE MOISTURE WHICH COULD LEAD TO ENHANCED RAINFALL AT TIMES. IN ADDITION...A SERIES OF SHORT WAVES WILL BE LIFTING NORTH THROUGH THE EASTERN FLANK OF THE UPPER LEVEL TROUGH...BUT THE TIMING OF THESE IMPULSES CANNOT BE PINNED DOWN AT THIS TIME. AS A RESULT...WILL FOLLOW THE PREVIOUS TREND OF INDICATING HIGHER POPS DURING THE AFTERNOON WHEN DAYTIME HEATING WILL LEAD TO A BETTER CHANCE FOR A FEW THUNDERSTORMS. ALL OF THESE FACTORS COULD LEAD TO A POTENTIAL FOR MORE FLOODING ISSUES...ESPECIALLY WITH THE ANTECEDENT MOISTURE THAT WILL BE IN PLACE FROM PREVIOUS RAINFALL. ABUNDANT CLOUD COVER AND SHOWER ACTIVITY ALONG WITH SLIGHTLY COOLER AIR ALOFT DUE TO THE PRESENCE OF THE UPPER LEVEL TROUGH WILL HELP KEEP TEMPERATURES SLIGHTLY BELOW AVERAGE DURING THIS PERIOD. && .LONG TERM /MONDAY THROUGH THURSDAY/... A DEEP UPPER LEVEL TROUGH EXTENDING FROM JAMES BAY ACROSS THE GREAT LAKES DOWN TO THE CENTRAL GULF COAST WILL GRADUALLY RETROGRADE WEST TO THE MISSISSIPPI VALLEY AS THE BERMUDA HIGH REASSERTS IT/S DOMINANCE OVER THE WESTERN ATLANTIC. THE PRESENCE OF A DEEP LAYERED SOUTHERLY FLOW AND AN ABUNDANT SUPPLY OF LOW LEVEL MOISTURE WILL KEEP WESTERN AND NORTH CENTRAL NEW YORK IN A FAVORABLE POSITION FOR UNSETTLED WEATHER THROUGH MUCH OF THE UPCOMING WEEK. THE BULK OF PRECIPITATION WILL BE IN THE FORM OF DIURNALLY DRIVEN CONVECTION WITH SHOWERS AND THUNDERSTORMS BREAKING OUT IN THE AFTERNOON AND EVENING HOURS EACH DAY. TEMPERATURES DURING THE PERIOD WILL SHOW A SLOW MODERATING TREND AS THE UPPER LEVEL TROUGH SLIDES WEST AND SOMEWHAT WARMER AIR OVER THE EAST COAST PUSHES BACK INTO THE LOWER GREAT LAKES. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... OVERALL...A VERY LOW CONFIDENCE AVIATION FORECAST GIVEN THE RATHER SPOTTY CONVECTION WHICH CAN TEMPORARILY LOWER CIGS/VSBY TO IFR OR LOWER. AT 09Z...A PATCHY IFR CLOUD DECK WAS IMPACTING A FEW SITES (ROC/JHW)...WHILE STEADIER RAIN LOWERED CIGS AT ART. STEADY RAINS AT ART SHOULD END MID-MORNING WITH IMPROVING CONDITIONS AFTER THIS. ELSEWHERE...EXPECT SHOWERS TO EXPAND...RESULTING IN LOWERING CIGS/VSBY AT BUF/IAG...AND SLIGHTLY IMPROVING CONDITIONS AT JHW. THESE WILL EVENTUALLY SPREAD TO ROC LATE MORNING. CONDITIONS WILL CONTINUE TO BE VARIABLE IN AND OUT OF SHOWERS. WITH MODEST INSTABILITY IN PLACE...A WIDELY SCATTERED THUNDERSTORM CANNOT BE RULED OUT AT ANY POINT TODAY...BUT WILL MOST LIKELY ACCOMPANY THE HEAVIEST RAIN SHOWERS. SHOWERS WILL GRADUALLY TAPER OFF THIS EVENING...BUT EVEN AS SHOWERS TAPER OFF SIGNIFICANT LOW MOISTURE MAY RESULT IN MVFR OR LOWER CONDITIONS OVERNIGHT. CONDITIONS WILL VARY...WITH ANY CLEARING ALOFT LIKELY TO BE QUICKLY FOLLOWED BY LOW CIGS/VSBY. OUTLOOK... SATURDAY THROUGH TUESDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NNE WINDS TO PICK UP THIS MORNING. CONDITIONS WILL BECOME A BIT CHOPPY...BUT WAVES ARE EXPECTED TO REMAIN BELOW SCA CRITERIA. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH THROUGH THIS EVENING FOR NYZ006>008. FLOOD WATCH THROUGH THIS EVENING FOR NYZ001>005-010>014- 019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...TJP/WOOD AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
338 AM EDT FRI JUN 28 2013 .SYNOPSIS... LOW PRESSURE WILL SLOWLY LIFT ACROSS EASTERN NEW YORK TODAY...WITH THIS LOW EXPECTED TO STALL NEAR THE REGION AS IT GRADUALLY WEAKENS THROUGH THE WEEKEND. THIS WILL BRING PERIODS OF RAIN TODAY...WITH EMBEDDED AREAS OF HEAVIER RAIN AND THUNDERSTORMS. THE THREAT FOR SHOWERS AND PERHAPS A THUNDERSTORM WILL PERSIST THROUGH THE WEEKEND...HOWEVER SHOWERS WILL BECOME INCREASINGLY SCATTERED AS THE WEEKEND WEARS ON. && .NEAR TERM /THROUGH TONIGHT/... THERE CONTINUES TO BE A POTENTIAL FOR FLOODING ACROSS PORTIONS OF WESTERN NEW YORK TODAY. THERE APPEARS TO BE TWO MAIN FEATURES TO WATCH TODAY...WITH THE MOST OBVIOUS BEING THE LARGE AREA OF RAIN ASSOCIATED WITH THE WEAK SURFACE LOW WHICH IS LIFTING ACROSS EASTERN NEW YORK STATE. RADAR TRENDS SUPPORT THE HRRR HANDLING OF THIS FEATURE...WHICH LARGELY KEEPS THE CORE OF IT TO THE SOUTH AND EAST OF OUR CWA. THIS SAID...EXPECT A RATHER QUICK INCH OF RAIN ACROSS LEWIS COUNTY THROUGH MID-MORNING...WITH LESSER AMOUNTS TO THE WEST IN JEFFERSON/OSWEGO COUNTIES. IF THIS HOLDS...WE PROBABLY WILL NOT SEE FLOODING...HOWEVER GIVEN THE CLOSE PROXIMITY OF HEAVIER RAINS WE WILL KEEP UP THE FLOOD WATCH. UPSTREAM RAINS WILL LIKELY CAUSE WITHIN BANK RISES ON THE BLACK RIVER AT BOONVILLE. THE SECOND FEATURE WE WILL BE KEEPING A CLOSE EYE ON IS A MORE SUBTLE UPPER LEVEL TROF AXIS WHICH EXTENDS FROM WESTERN NEW YORK BACK INTO SOUTHERN ONTARIO TO GEORGIAN BAY. SCATTERED...BUT VERY SLOW MOVING...SHOWERS ALONG THIS AXIS ARE FORECAST TO EXPAND BY THE HRRR. SEVERAL RUNS OF THE NAM/RGEM SUPPORT THE HRRR FORECAST...AND GIVEN A FAIRLY GOOD TRACK RECORD FOR THIS EVENT...HAVE MODERATE CONFIDENCE IN ITS FORECAST. EXPECT SHOWERS TO DEVELOP ALONG A NW-SE AXIS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AROUND DAYBREAK...WITH THIS AXIS LIKELY TO SLOWLY LIFT NORTH TO A BUFFALO TO WELLSVILLE LINE BY EARLY AFTERNOON...THEN EVENTUALLY FURTHER NORTH AND EAST BY LATE AFTERNOON. THIS PRECIPITATION WILL BE CONVECTIVE...WITH BUFKIT SHOWING A MOIST SOUNDING WITH THIN AND NARROW CAPES...AND P-WAT VALUES AROUND 1.6 INCHES. CONSENSUS QPFS FROM THE HIGHER RESOLUTION MODELS INCLUDING RECENT RUNS OF THE NAM/RGEM/SREF ONLY AVERAGE AROUND AN INCH WITH THIS. HOWEVER...GIVEN THE SLOW MOTION OF THE CONVECTIVE CELLS...LOCALLY HIGHER AMOUNTS ARE POSSIBLE. YESTERDAY EVENING SLOW MOVING SHOWERS RESULTED IN RADAR ESTIMATES OF OVER 3 INCHES IN A FEW SPOTS IN SOUTHERN ONTARIO PROVINCE. RAIN AMOUNTS IN EXCESS OF TWO INCHES WOULD BE A CONCERN PRETTY MUCH ANYWHERE...WITH URBAN AREAS...THE BUFFALO CREEKS...AND AREAS WITH RECENT RAINS VULNERABLE TO LESSER RAINFALL AMOUNTS. FOLLOWING THIS...WILL KEEP THE FLOOD WATCH UP IN WESTERN NEW YORK AS WELL. THE UPPER LOW WILL GRADUALLY MOVE ACROSS THE REGION TONIGHT...WHICH WILL EFFECTIVELY END THIS AXIS AS THE LOW BECOMES VERTICALLY STACKED. THERE WILL BE A LINGERING THREAT FOR SHOWERS TONIGHT...WITH SHOWERS EXPECTED TO BECOME INCREASINGLY SCATTERED IN NATURE AS THE NIGHT GOES ON. WHILE WIDESPREAD THUNDERSTORMS ARE NOT LIKELY...THERE MAY BE SOME EMBEDDED IN AREAS OF HEAVY RAIN TODAY. TEMPERATURES WILL NOT RISE VERY MUCH AT ALL TODAY...WITH PERSISTENT CLOUDS COVER AND AREAS OF SHOWERS. EXPECT HIGHS TO ONLY BE AROUND 70 DEGREES IN MOST LOCATIONS. OVERNIGHT LOWS SHOULD DROP INTO THE UPPER 50S TO LOWER 60S. PATCHY FOG IS LIKELY...AND WHILE MOSTLY CLOUDY SKIES ARE EXPECTED...ANY CLEARING WOULD QUICKLY FAIRLY DENSE FOG DEVELOPMENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A FULL LATITUDE TROUGH IS FORECAST TO REMAIN IN PLACE FROM SOUTHERN QUEBEC TO THE TENNESSEE VALLEY THROUGH THIS PERIOD. THE DEEP LAYERED SOUTHERLY FLOW WILL KEEP MOIST AND SOMEWHAT UNSTABLE AIR OVER OUR AREA WHICH WILL LEAD TO OCCASIONAL SHOWERS AND SCATTERED THUNDERSTORMS. THE MODELS AGREE THAT A LOW LEVEL TROUGH/BAROCLINIC ZONE WILL REMAIN STALLED OVER CENTRAL NEW YORK STATE. THIS BOUNDARY WILL HELP TO FOCUS THE MOISTURE WHICH COULD LEAD TO ENHANCED RAINFALL AT TIMES. IN ADDITION...A SERIES OF SHORT WAVES WILL BE LIFTING NORTH THROUGH THE EASTERN FLANK OF THE UPPER LEVEL TROUGH...BUT THE TIMING OF THESE IMPULSES CANNOT BE PINNED DOWN AT THIS TIME. AS A RESULT...WILL FOLLOW THE PREVIOUS TREND OF INDICATING HIGHER POPS DURING THE AFTERNOON WHEN DAYTIME HEATING WILL LEAD TO A BETTER CHANCE FOR A FEW THUNDERSTORMS. ALL OF THESE FACTORS COULD LEAD TO A POTENTIAL FOR MORE FLOODING ISSUES...ESPECIALLY WITH THE ANTECEDENT MOISTURE THAT WILL BE IN PLACE FROM PREVIOUS RAINFALL. ABUNDANT CLOUD COVER AND SHOWER ACTIVITY ALONG WITH SLIGHTLY COOLER AIR ALOFT DUE TO THE PRESENCE OF THE UPPER LEVEL TROUGH WILL HELP KEEP TEMPERATURES SLIGHTLY BELOW AVERAGE DURING THIS PERIOD. && .LONG TERM /MONDAY THROUGH THURSDAY/... A DEEP UPPER LEVEL TROUGH EXTENDING FROM JAMES BAY ACROSS THE GREAT LAKES DOWN TO THE CENTRAL GULF COAST WILL GRADUALLY RETROGRADE WEST TO THE MISSISSIPPI VALLEY AS THE BERMUDA HIGH REASSERTS IT/S DOMINANCE OVER THE WESTERN ATLANTIC. THE PRESENCE OF A DEEP LAYERED SOUTHERLY FLOW AND AN ABUNDANT SUPPLY OF LOW LEVEL MOISTURE WILL KEEP WESTERN AND NORTH CENTRAL NEW YORK IN A FAVORABLE POSITION FOR UNSETTLED WEATHER THROUGH MUCH OF THE UPCOMING WEEK. THE BULK OF PRECIPITATION WILL BE IN THE FORM OF DIURNALLY DRIVEN CONVECTION WITH SHOWERS AND THUNDERSTORMS BREAKING OUT IN THE AFTERNOON AND EVENING HOURS EACH DAY. TEMPERATURES DURING THE PERIOD WILL SHOW A SLOW MODERATING TREND AS THE UPPER LEVEL TROUGH SLIDES WEST AND SOMEWHAT WARMER AIR OVER THE EAST COAST PUSHES BACK INTO THE LOWER GREAT LAKES. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... OVERALL...A VERY LOW CONFIDENCE AVIATION FORECAST GIVEN THE RATHER SPOTTY CONVECTION WHICH CAN TEMPORARILY LOWER CIGS/VSBY TO IFR OR LOWER. OUTSIDE OF THIS...CONDITIONS ARE MAINLY VFR AT 06Z...OUTSIDE OF PATCHY AREAS OF DENSE FOG AND VLIFR CIGS. THIS TREND IS LIKELY TO CONTINUE THROUGH THE EARLY MORNING HOURS...EXCEPT THAT STEADIER RAIN SHOWERS ARE LIKELY TO DEVELOP ACROSS WESTERN AREAS FROM JHW TO BUF/IAG...AND EVENTUALLY ROC. THIS SHOULD LEAD TO LOWERING CONDITIONS DURING THE MORNING HOURS. ART IS A DIFFERENT STORY WITH STEADIER RAINS LIKELY TO BACK IN FROM THE EAST OVERNIGHT. DURING THE DAYTIME HOURS...SHOWERS SHOULD BECOME A BIT MORE SCATTERED IN NATURE...EVENTUALLY TAPERING OFF DURING THE EVENING HOURS. WITH MODEST INSTABILITY IN PLACE...A WIDELY SCATTERED THUNDERSTORM CANNOT BE RULED OUT AT ANY POINT TODAY...BUT WILL MOST LIKELY ACCOMPANY THE HEAVIEST RAIN SHOWERS. EVEN AS SHOWERS TAPER OFF...SIGNIFICANT LOW MOISTURE MAY RESULT IN MVFR OR LOWER CONDITIONS OVERNIGHT. CONDITIONS WILL VARY...WITH ANY CLEARING ALOFT LIKELY TO BE QUICKLY FOLLOWED BY LOW CIGS/VSBY. OUTLOOK... SATURDAY THROUGH TUESDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NNE WINDS TO PICK UP THIS MORNING. CONDITIONS WILL BECOME A BIT CHOPPY...BUT WAVES ARE EXPECTED TO REMAIN BELOW SCA CRITERIA. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH THROUGH THIS EVENING FOR NYZ006>008. FLOOD WATCH THROUGH THIS EVENING FOR NYZ001>005-010>014- 019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...TJP/WOOD AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
142 AM EDT FRI 28 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL HOLD OVER THE REGION FOR THE NEXT SEVERAL DAYS... AS A LARGE LOW PRESSURE TROUGH HOLDS OVER THE EASTERN HALF OF THE COUNTRY. PASSING UPPER LEVEL DISTURBANCES WILL HELP PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH FRIDAY NIGHT/... AS OF 935 PM THURSDAY... THE LAST CLUSTER OF ORGANIZED CONVECTION CONTINUES MOVING TO THE ESE OVER THE SRN PIEDMONT AND SW SANDHILLS. OTHER MORE ISOLATED CELLS ELSEWHERE HAVE BECOME STRONG BUT THEIR HIGH-REFLECTIVITY CORES HAVE NOT QUITE REACHED THE HEIGHTS OF EARLIER STORMS. THE BOUNDARY LAYER CONTINUES TO SLOWLY BUT STEADILY STABILIZE WITH MLCAPE DOWN TO 1500 J/KG AND GROWING CINH... AND THIS TREND SHOULD CONTINUE WITH STORMS DISSIPATING IN THE NEXT FEW HOURS. THE LATEST COUPLE OF HRRR RUNS AS WELL AS THE SREF AND WRF SUPPORT THIS SCENARIO WITH REMAINING STORMS SHIFTING TO OUR EAST AND WEAKENING. DYNAMIC SUPPORT FOR ASCENT WILL BE WANING AS THE VORTICITY AXIS SHIFTS TO OUR EAST... LEAVING BEHIND BAGGY MID LEVEL TROUGHING OVERNIGHT WITH A LINGERING DIFFUSE TROUGH AT THE SURFACE THROUGH THE CENTRAL CAROLINAS. WILL HOLD ONTO EXISTING FORECAST TREND OF POPS DECREASING WEST TO EAST. EXPECT FAIR TO PARTLY CLOUDY SKIES OVERNIGHT... ALTHOUGH THE MORE WIDESPREAD SHOWERS/STORMS IN THE EAST ALONG WITH SLIGHTLY HIGHER DEW POINTS AND 925-850 MB MOISTURE SHOULD YIELD MORE WIDESPREAD STRATUS IN OUR EAST. WITH THE RAIN-COOLED AIR IN SOME AREAS... CURRENT TEMPS HAVE FALLEN TO WITHIN A FEW DEGREES OF THE DEW POINT AND HENCE ARE CLOSE TO THE NIGHTTIME LOWS. CURRENT TEMP TRENDS PLUS STATISTICAL GUIDANCE SUPPORT LOWS CLOSE TO THE CURRENT FORECAST OF 69-74. -GIH FRIDAY... SHORTWAVE ENERGY DIGGING THROUGH THE UPPER MIDWEST WILL CONTINUE TO DEEPEN THE UPPER LEVEL TROUGH DEVELOPING OVER THE EASTERN US. A SHARP PIEDMONT TROUGH WILL BE IN PLACE DURING THE DAY ON FRIDAY..WITH LITTLE CHANGE IN AIRMASS EXPECTED OUTSIDE OF SLIGHTLY LOWER DEWPOINTS IN THE WESTERN PIEDMONT. CYCLONIC FLOW ALOFT...ALBEIT WITHOUT A NOTABLE TRIGGER IN THE MODELS...AND MODEST INSTABILITY WILL ONCE AGAIN SUPPORT SCATTERED TO NUMEROUS THUNDERSTORMS DURING THE AFTERNOON. WHILE ITS POSSIBLE THAT COVERAGE MAY NOT BE AS GREAT AS THIS AFTERNOON...MID-LEVEL FLOW WILL BE STRONGER AND DEEP LAYER SHEAR IS PROGGED TO TO EXCEED 30KT...SUGGESTING MULTICELLULAR ORGANIZATION. THE CURRENT SPC DAY TWO OUTLOOK INCLUDES ALL OF CENTRAL NC IN A SLIGHT RISK. REGARDING HIGH TEMPS...GUIDANCE ALMOST UNANIMOUSLY GIVES VALUES A FEW DEGREES WARM THAN TODAY...WITH LOWER 90S ACROSS A LARGE PORTION OF THE CWA. THIS WILL LIKELY LEAD TO HEAT INDICES NEAR 100 ACROSS THE SANDHILLS AND SOUTHERN PIEDMONT WHERE DEWPOINTS SHOULD HOVER IN THE LOWER 70S. FRIDAY NIGHT... WILL CONTINUE AT LEAST A SLIGHT CHANCE OF SHOWERS AND STORMS THROUGH FRIDAY NIGHT AS HEIGHTS CONTINUE TO SLOWLY FALL ALOFT AND THE AIRMASS OVER NC REMAINS HUMID. LOWS IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM THURSDAY... AN ANOMALOUSLY AMPLIFIED PATTERN WILL PREVAIL ACROSS THE CONUS THROUGH THE WEEKEND...CHARACTERIZED BY A DEEP UPPER LEVEL RIDGE OVER THE ROCKIES/INTERMOUNTAIN WEST AND DEEP TROUGHING EAST OF THE MISSISSIPPI...WITH A PERSISTENT UPPER LEVEL LOW CENTERED IN VICINITY OF THE LOWER GREAT LAKES AND OH VALLEY. ACROSS THE CAROLINAS AND MID-ATLANTIC...EXPECT ATYPICALLY STRONG SOUTHWEST FLOW ALOFT WITH NUMEROUS SMALL AMPLITUDE SHORTWAVES CROSSING THE REGION THROUGHOUT THE PERIOD IN THE PRESENCE OF A SEASONABLY MOIST AIRMASS. AS A RESULT...EXPECT ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS AND SLIGHTLY BELOW NORMAL HIGH TEMPS IN THE MID 80S...DEPENDING ON CLOUD COVER AND CONVECTION. THE EXACT COVERAGE AND PERSISTENCE OF CONVECTION WILL HIGHLY DEPEND ON THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT AND THE TIMING OF THESE DISTURBANCES IN RELATION TO THE DIURNAL HEATING CYCLE. FURTHERMORE...THE DEGREE OF DIURNAL DESTABILIZATION IS DIFFICULT TO ASCERTAIN GIVEN INCREASED CLOUD COVER AND AN ABOVE NORMAL CHANCE FOR NOCTURNAL OR EARLY MORNING CONVECTION...THOUGH ONE WOULD EXPECT AT LEAST SOME CLOUD BREAKS AND AREAS OF RELATIVELY STRONGER INSOLATION DURING PEAK HEATING. EITHER WAY...SLIGHTLY STEEPER MID-LEVEL LAPSE RATES /COOLER TEMPS ALOFT/ IN ASSOCIATION WITH THE UNUSUALLY AMPLIFIED UPPER LEVEL TROUGH OVER THE REGION WILL AT LEAST SOMEWHAT COMPENSATE FOR DECREASED INSOLATION. GIVEN DEEP-LAYER (0-6 KM) SHEAR LIKELY IN THE 35-45 KT RANGE...ORGANIZED CONVECTION WILL CERTAINLY BE POSSIBLE... INCLUDING SUPERCELLS...THOUGH THE TYPE/EXTENT OF ANY SEVERE THREAT CANNOT BE PRECISELY IDENTIFIED AT THIS TIME. IN ADDITION TO A POTENTIAL FOR SEVERE THUNDERSTORMS...ISOLATED FLASH FLOODING WILL ALSO BE POSSIBLE GIVEN RECENT HEAVY RAINFALL AND ABOVE NORMAL CHANCES FOR CONVECTION THROUGH THE WEEKEND. -VINCENT && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY... AN UNSEASONABLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST ACROSS THE CONUS THROUGH THE MIDDLE OF NEXT WEEK...CHARACTERIZED BY RIDGING OVER THE INTERMOUNTAIN WEST...TROUGHING CENTERED IN VICINITY OF THE MS RIVER VALLEY AND ATYPICALLY STRONG SW FLOW ALOFT OVER THE CAROLINAS. NUMEROUS SMALL AMPLITUDE DISTURBANCES IN THE PRESENCE OF ABOVE NORMAL MOISTURE (PWAT ~2.00") WILL RESULT IN ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH EARLY/MID NEXT WEEK... MODULATED PRIMARILY BY THE DIURNAL HEATING CYCLE...IN ADDITION TO A CONTINUED THREAT FOR SEVERE WEATHER (GIVEN FAVORABLE DEEP-LAYER SHEAR) AND ISOLD FLASH FLOODING. IN GENERAL EXPECT HIGHS SEVERAL DEGREES BELOW NORMAL DUE TO INCREASED CLOUD COVER AND CHANCES FOR CONVECTION. -VINCENT && .AVIATION /06Z THURSDAY THROUGH TUESDAY/... AS OF 145 AM FRIDAY... UPPER S/W VORT DISTURBANCE AND ASSOCIATED CONVECTION WILL EXIT THE SANDHILLS AND SOUTHERN COASTAL COUNTIES BY 08Z WITH SUBSIDENCE IN THE WAKE OF THE UPPER DISTURBANCE ALLOWING FOR DRY CONDITIONS FOR THE SECOND PART OF THE NIGHT. PATCHY SUB-VFR STRATUS AND/OR FOG IS POSSIBLE AROUND DAYBREAK...PARTICULARLY IN AREAS THAT SAW HEAVY RAIN THIS PAST EVENING. ANY STRATUS/FOG SHOULD LIFT BY 15Z THIS MORNING... WITH PREDOMINATELY VFR CONDITIONS INTO THE EARLY AFTERNOON BEFORE ANOTHER ROUND OF SCATTERED TO NUMEROUS STORMS ARE EXPECTED OVER CENTRAL NC. LOOKING BEYOND FRIDAY...THE WEATHER PATTERN WILL CHANGE VERY LITTLE THE NEXT SEVERAL DAYS. AN UNSEASONABLY STRONG LOW PRESSURE TROUGH COMBINED WITH A WARM AND UNSTABLE AIR WILL RESULT IN SCATTER TO NUMEROUS SHOWERS AND STORMS EACH AFTERNOON/EARLY EVENING... AND THE POTENTIAL FOR STRATUS OR FOG EACH MORNING. && .EQUIPMENT... KRAX WSR-88D WILL BE REMAIN DOWN OR IN DEGRADED MODE THROUGH FRIDAY MORNING. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE... AND IS WORKING TO RETURN THE RADAR TO NORMAL SERVICE BY EARLY AFTERNOON FRIDAY. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BLS SHORT TERM...VINCENT LONG TERM...VINCENT AVIATION...CBL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
144 AM EDT FRI JUN 28 2013 .SYNOPSIS... UNSETTLED WEATHER WILL CONTINUE THROUGH THE MIDDLE OF NEXT WEEK WITH A DAILY RISK OF SHOWERS AND THUNDERSTORMS. SIGNIFICANT RAINFALL AMOUNTS ARE EXPECTED THROUGH THE PERIOD AND THIS RAIN WILL BE FALLING ON ALREADY WET SOILS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1030 PM THURSDAY...THE LAST IN THE SERIES OF SHORTWAVE DISTURBANCES ALOFT WILL PUSH ACROSS THE EASTERN CAROLINAS IN THE NEXT SEVERAL HOURS...LIKELY SUSTAINING CONVECTION ACROSS THE AREA THROUGH MIDNIGHT AND PERHAPS BEYOND. WITH SUCH A HUMID AIRMASS (PRECIPITABLE WATER 2.0 TO 2.1 INCHES AND SURFACE DEWPOINTS IN THE 70S) VIRTUALLY ANY STORM CELL IS PRODUCING RAINFALL RATES IN EXCESS OF 1 INCH PER HOUR. BASED MAINLY ON CURRENTLY OBSERVED RADAR TRENDS I HAVE ADJUSTED POPS UP FOR THE NEXT 3-4 HOURS TO 100 PERCENT FROM EASTERN COLUMBUS COUNTY THROUGH THE WILMINGTON METRO AREA...AND JUST SOUTH OF FLORENCE TO NEAR KINGSTREE. THIS ACTIVITY IS PROBABLY NO LONGER SURFACE BASED BUT IS TAKING ADVANTAGE OF A STRENGTHENING LOW LEVEL JET WHICH IS ADVECTING IN EXTREMELY HUMID AIR OFF THE ATLANTIC WITH DEWPOINTS IN THE UPPER 70S. FLOOD ADVISORIES OR WARNINGS MAY NEED TO BE ISSUED IN THE NEXT HOUR OR TWO GIVEN THE SLOW OBSERVED CELL MOTION COUPLED WITH HIGH RAINFALL RATES. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A SERIES OF TWO UPPER LEVEL DISTURBANCES ROLLING ACROSS A STRONGLY UNSTABLE AIRMASS LED TO THE DEVELOPMENT OF WIDESPREAD THUNDERSTORMS THIS AFTERNOON. SURFACE-BASED INSTABILITY IS NOW WANING WITH THE LOSS OF INSOLATION AND THE LARGE-SCALE OVERTURNING OF THE AIRMASS. HOWEVER CONSIDERABLE INSTABILITY (CAPE: 3000 J/KG) REMAINS SOUTH AND WEST OF FLORENCE WITH LESSER INSTABILITY ALONG THE COAST FROM MYRTLE BEACH THROUGH WILMINGTON. (A SMALL NEGATIVE REGION OF CONVECTIVE INHIBITION ALONG THE COAST COULD PREVENT THIS INSTABILITY FROM BEING REALIZED) SYNOPTIC MODELS ARE OFTEN OF LITTLE USE IN FORECASTING CONVECTION. THE HRRR HIGH-RESOLUTION MODEL IS HAVING TROUBLE INITIALIZING THE STORM PROPERLY BUT THE LAST SEVERAL RUNS SUGGEST THE INSTABILITY SOUTH OF FLORENCE TOWARD THE SANTEE RIVER INTO THE CHARLESTON METRO AREA WILL BE THE BREEDING GROUND FOR ANOTHER CLUSTER OF CONVECTION OVER THE NEXT SEVERAL HOURS. THE FINAL UPPER LEVEL SHORTWAVE MOVING SOUTHEAST THROUGH THE PIEDMONT REGION COULD ALSO IGNITE NEW STORMS ACROSS THE SANDHILLS IN THE NEXT FEW HOURS WITH THE INTERSTATE 95 CORRIDOR POTENTIALLY RECEIVING ANOTHER ROUND OF ACTIVITY. IN TERMS OF FORECAST POPS...I HAVE THE HIGHEST POPS FOR THE NEXT FEW HOURS ACROSS NORTHERN ROBESON INTO BLADEN COUNTIES IN NC. BY LATE THIS EVENING I SHIFT THE BULLSEYE SOUTHWARD FROM JUST INLAND OF GEORGETOWN ACROSS CENTRAL HORRY COUNTY TO NEAR WILMINGTON. (50-60 PERCENT) AFTER MIDNIGHT MOST OF THE CONVECTIVE ACTIVITY SHOULD SHIFT OFFSHORE BEHIND THE FINAL SHORTWAVE ALOFT...WITH DRYING CONDITIONS TEMPORARILY BUILDING IN FROM THE WEST. I SAY TEMPORARILY BECAUSE THE PATTERN FOR TOMORROW AFTERNOON THROUGH THE WEEKEND IS WET TO SAY THE LEAST! FORECAST LOWS TONIGHT RANGE FROM 72-77...COOLEST WEST OF I-95 AND WARMEST ALONG THE COAST. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...A BROAD UPPER LOW ACROSS THE GREAT LAKES WILL SLOWLY RELOCATE ACROSS THE OHIO VALLEY DURING THIS PERIOD. MID-LEVEL SHORTWAVE ENERGY ROTATING AROUND THE UPPER LOW WILL HELP TO ENHANCE SHOWERS AND THUNDERSTORMS. SURFACE FEATURES THAT WILL HELP TO CONVERGE AND LIFT A MOIST AND UNSTABLE AIRMASS INCLUDE THE SEABREEZE AND THE PIEDMONT TROUGH. OVERALL...A WET PERIOD IS IN STORE WITH BOUTS OF SHOWERS AND THUNDERSTORMS. RAINFALL AMOUNTS JUST DURING THIS PERIOD WILL LIKELY ADD ANOTHER 1 TO 2 INCHES TO WHAT HAS BEEN A VERY WET JUNE ALREADY. AS IS USUALLY THE CASE WITH CONVECTION...SOME SPOTS COULD RECEIVE AMOUNTS CONSIDERABLY HIGHER THAN THIS RANGE. IT LOOKS AS THOUGH ONE SUCH SHORTWAVE WILL LIFT OUT ACROSS THE EASTERN CAROLINAS DURING FRI AFTERNOON. MIXED LAYER CAPE VALUES ARE VERY HIGH ON FRI...REACHING 3000 J/KG. MID-LEVEL LAPSE RATES ARE HOWEVER MODEST. THE FLOW IS LARGELY WESTERLY...EXCEPT SW IN THE LOWEST 3-5 KFT OR SO. THERE IS CONSIDERABLE DRY AIR IN THE MID-LEVELS FRI MORNING...BUT THEN OVERTIME...THE COLUMN MOISTENS FROM W TO E...DURING THE AFTERNOON AND EVE. THUS...THE SCENARIO PAINTED BY SEVERAL OF THE MODELS LOOKS REASONABLE...SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THE PIEDMONT TROUGH IN RESPONSE TO STRONG HEATING AND MOVING ACROSS OUR WESTERN ZONES FRI AFTERNOON AND THEN TO THE COAST FRI EVE/NIGHT. A FEW STORMS MAY ALSO POP ALONG THE SEABREEZE FRI AFTERNOON. GIVEN THE MAGNITUDE OF INSTABILITY AND DEVELOPING INVERTED V SOUNDINGS...THERE IS A RISK FOR STRONG TO POSSIBLY DAMAGING WINDS IN THE DEEPEST CONVECTION. MID-LEVEL TEMPS SHOULD BE COOL ENOUGH TO SUPPORT HAIL IN ANY STRONG AND PERSISTENT UPDRAFTS. THIS IS IN ADDITION TO THE HEAVY RAIN AND FREQUENT DEADLY LIGHTING RISK. THE CONVECTION SHOULD ONLY SLOWLY WANE WITH LOSS OF HEATING THROUGH THE LATE EVE AND OVERNIGHT. SAT...THE FLOW TURNS MORE SOUTHWESTERLY THROUGH A DEEP LAYER AND THERE IS NO DRY AIR IN THE COLUMN TO BE FOUND. THE COLUMN IS SATURATED OR NEARLY SO THROUGH A DEEP LAYER. SOME OF THE MODELS ARE INDICATING A SHORTWAVE TROUGH MOVING UP THE COAST...BUT A GOOD DISTANCE OFFSHORE. WE WILL HAVE TO WATCH THIS FEATURE TO SEE HOW IT EVENTUALLY PLAYS OUT. THERE MAY BE SOME SUBSIDENCE DEVELOPING ON THE BACK SIDE WHICH WOULD TEND TO SUPPRESS/REDUCE CONVECTION. HOWEVER...CLOSER TO THE COAST AND THERE COULD BE CONSIDERABLE CONVECTION AT AND NEAR THE COAST. GIVEN THE ENVIRONMENT...IT WILL TAKE VERY LITTLE TO IGNITE CONVECTION. STORM MOTIONS SHOULD BE MUCH QUICKER ON SAT THAN ON FRI AS THE WIND FIELDS WILL BE STRONGER. WET MICROBURSTS CAN NOT BE RULED OUT ON SAT. CLOUD COVER SHOULD BE MORE WIDESPREAD SAT THAN ON FRI GIVEN THE EXPECTED MOISTURE PROFILES. WILL THUS FORECAST HIGHER TEMPS ON FRI...LOWER TO MID 90S. THE SEABREEZE SHOULD BE PINNED NEAR THE COAST AND SO EVEN THE BEACHES SHOULD REACH THE UPPER 80S WITH THE EXCEPTION OF BRUNSWICK AND SOUTHERN NEW HANOVER COUNTIES WHERE A MORE ONSHORE FLOW SHOULD KEEP AFTERNOON TEMPS IN THE MID 80S. HIGHS ON SAT WILL BE MAINLY IN THE UPPER 80S TO AROUND 90 WELL INLAND WITH MID 80S AT THE BEACHES AS THE SEABREEZE SHOULD BE ABLE TO MAKE A LITTLE FURTHER PROGRESS INLAND. LOWS WILL BE IN THE MUGGY 70S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 3 PM THURSDAY...ACTIVE WEATHER WILL CONTINUE THROUGH AT LEAST THE FIRST HALF OF THE WEEK. MID TO UPPER TROUGH DIGGING DOWN THROUGH THE MISSISSIPPI VALLEY ON SUNDAY WILL LIFT TOWARD THE NORTHWEST AS STRONG UPPER RIDGE TO OUR EAST TRIES TO BUILD WESTWARD ACROSS THE EAST COAST. INITIALLY LOCAL AREA WILL REMAIN BETWEEN THESE TWO FEATURES ON THE ACTIVE SIDE OF MID TO UPPER TROUGH. SHORTWAVE ENERGY WILL ROTATE AROUND THE TROUGH UP THROUGH THE CAROLINAS ENHANCING LOCALIZED CONVECTION SUNDAY THROUGH MID WEEK. THE CONVECTION SHOULD FIRST FIRE UP OVER THE SEA BREEZE CONVERGENT BOUNDARY AND THE PIEDMONT TROUGH INLAND BUT THEN WILL BECOME MORE WIDESPREAD ALONG MESO OUTFLOW BOUNDARIES. OVERALL WILL REMAIN IN DEEP MOIST SOUTHERLY FLOW AND EXPECT PLENTY OF CLOUDS AND CONVECTION EACH DAY IN A WARM AND HUMID SUMMERTIME AIR MASS. THE STEERING FLOW WILL KEEP STORMS MOVING FROM SOUTH TO NORTH AND MAY ALLOW FOR BETTER WEATHER ALONG THE IMMEDIATE COAST. AS MID TO UPPER TROUGH LIFTS FARTHER NORTH INTO CANADA THE RIDGE MAY MAKE IT FAR ENOUGH WEST TO PROVIDE SOME SUBSIDENCE AND DRYING THROUGH THE MID LEVELS OF THE ATMOSPHERE BY WED OR THURS. WITHOUT THE UPPER LEVEL SUPPORT WE CAN GET BACK TO LESS IN THE WAY OF STRONGER CONVECTION AND JUST LOCALIZED SHOWER ACTIVITY ALONG THE SEA BREEZE AND PIEDMONT TROUGH. TEMPS WILL RUN NEAR OR ABOVE NORMAL THROUGH THE PERIOD WITH 70S FOR OVERNIGHT LOWS AND CLOSE TO 90 FOR AFTERNOON HIGHS. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 06Z...SLOWLY WEAKENING SHOWERS AND ISOLATED THUNDERSTORMS WITH HEAVY RAINFALL WILL CONTINUE ACROSS THE INLAND TERMINALS EARLY THIS MORNING. THE ACTIVITY WILL WEAKEN AS IT PUSHES TOWARD THE COAST AND ACROSS AN AREA THATS BEEN WORKED OVER EARLIER BY CONVECTION. TEMPO MVFR CONDITIONS WILL BE NEEDED WITH THIS ACTIVITY. IFR/LIFR CONDITIONS AS WELL AS VARIABLE WIND GUSTS TO 30 KTS WILL OCCUR IF A THUNDERSTORM MOVES DIRECTLY OVER ANY TERMINAL. CONVECTION WILL GRADUALLY DECREASE IN COVERAGE THROUGH SUNRISE. THERE IS MODERATE CONFIDENCE IFR CIGS/MVFR VSBYS WILL DEVELOP AT KFLO/KLBT 08-12Z. COASTAL TERMINALS SHOULD REMAIN VFR OUTSIDE OF PRECIPITATION AREAS. SHOWERS SHOULD BE MAINLY OFFSHORE AFTER SUNRISE...BUT REDEVELOPMENT ALONG THE SEA BREEZE MID-LATE MORNING AND NEAR KFLO/KLBT...EAST OF THE PIEDMONT TROF...DURING THE AFTERNOON IS EXPECTED. VFR EXPECTED OUTSIDE OF PRECIPITATION AREAS. EXTENDED OUTLOOK...ISOLATED/SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS THROUGH TUESDAY WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...NEW THUNDERSTORMS ARE MOVING OFF THE COAST NORTH OF CAPE FEAR. THESE STORMS MAY BE FOLLOWED BY MORE WAVES OF STORMS OVERNIGHT AS ANOTHER UPPER LEVEL DISTURBANCE PUSHES OFF THE COAST. THE UPDATED FORECAST FEATURES INCREASED THUNDERSTORM POTENTIAL THROUGH ABOUT 2-3 AM FRIDAY...WITH LESSENING CHANCES LATE TONIGHT. ALTHOUGH SYNOPTIC-SCALE WINDS WILL REMAIN FROM THE SOUTHWEST AT 15-25 KNOTS...OBVIOUSLY THUNDERSTORM-SCALE WINDS MUCH TOO SMALL TO FORECAST MORE THAN 1-2 HOURS IN ADVANCE WILL DOMINATE THE WEATHER THROUGH THE NIGHT. MARINERS SHOULD CLOSELY WATCH FOR THESE STORMS AS THEY ARE PRODUCING CONTINUOUS LIGHTNING... TORRENTIAL RAINFALL AND REDUCED VISIBILITIES...AND STRONG GUSTY WINDS. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A FAIRLY TIGHT PRESSURE GRADIENT EXISTS BETWEEN A PIEDMONT TROUGH NEARLY STATIONARY INLAND AND THE BERMUDA HIGH WELL OFFSHORE. THIS IS PRODUCING A HEALTHY SOUTH-SOUTHWEST BREEZE AT 15-25 KNOTS THIS EVENING. ALTHOUGH MODELS SUGGEST WIND SPEEDS WILL RELAX A LITTLE AFTER MIDNIGHT...THE TIGHT GRADIENT SHOULD REMAIN WITH STRONGER WINDS REDEVELOPING FRIDAY. SEVERAL CLUSTERS OF THUNDERSTORMS INLAND ARE WEAKENING AS THEY APPROACH THE COAST...BUT THE POTENTIAL REMAINS FOR REDEVELOPMENT OF SHOWERS AND STORMS ACROSS THE COASTAL WATERS...MAINLY FROM LATE THIS EVENING THROUGH ABOUT 3 AM FRIDAY. THUNDERSTORMS CHANCES ARE SLIGHTLY HIGHER NORTH OF MYRTLE BEACH BUT I CAN`T RULE OUT STORMS ACROSS THE SC WATERS EITHER. I HAVE MADE SUBSTANTIAL EDITS TO SEA HEIGHTS BASED ON DATA FROM THE OCEAN CREST PIER WAVE GAUGE WHICH IS REPORTING 3-4 FT SEAS JUST OUTSIDE THE SURF ZONE. LARGER SEAS OFTEN PENETRATE RIGHT UP TO THE BEACHES ON A GOOD ONSHORE WIND HERE...AN EFFECT EVEN OUR HIGH RESOLUTION "SWAN" WAVE MODEL DOESN`T SEEM TO BE ABLE TO HANDLE. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM THURSDAY...A SMALL CRAFT ADVISORY HAS BEEN EXTENDED FOR ALL AREAS UNTIL 6 PM SAT. THE PRESSURE GRADIENT BETWEEN A PIEDMONT TROUGH INLAND AND THE BERMUDA RIDGE WILL HELP TO KEEP WINDS AND SEAS ELEVATED THIS PERIOD. WINDS WILL REACH UP TO 20 TO 25 KT. WINDS WILL BE SW THROUGH THE PERIOD...SLIGHTLY MORE W OF S ON FRI THAN ON SAT. SEAS WILL PEAK IN THE 4 TO 7 FT RANGE. SE...8 TO 9 SECOND SWELL... WILL BE WEAK DURING THIS PERIOD AND WAVE HEIGHTS WILL BE THE RESULT OF INCREASING WIND WAVE ENERGY. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 3 PM THURSDAY...SOUTHERLY FLOW WILL CONTINUE AROUND WESTERN PERIPHERY OF BERMUDA HIGH THROUGH EARLY NEXT WEEK. GRADIENT WILL REMAIN FAIRLY TIGHT THROUGH THE WEEKEND BETWEEN LOW AND PIEDMONT TROUGH INLAND AND HIGH PRESSURE OFF SHORE. WINDS WILL GENERALLY BE AROUND 15 KTS NEAR SHORE WITH A SPIKE UP EACH AFTN IN SEA BREEZE. WINDS WILL BE UP AROUND 20 IN OUTER WATERS AND UP TO 25 KTS IN WATERS NORTH FRYING PAN. PERSISTENT SOUTHERLY FLOW WILL KEEP SEAS UP AROUND 4 TO 6 FT THROUGH THE PERIOD. WILL MOST LIKELY END UP WITH AN EXTENDED PERIOD OF SMALL CRAFT ADVISORY CONDITIONS FOR 6 TO 7 FT SEAS IN STRONGER SOUTHERLY FLOW ESPECIALLY IN OUTER WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR AMZ250-252- 254-256. && $$ SYNOPSIS...RJD NEAR TERM...TRA SHORT TERM...RJD LONG TERM...RGZ AVIATION...DCH/MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
142 AM EDT THU FRI 28 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS WILL HOLD OVER THE REGION FOR THE NEXT SEVERAL DAYS... AS A LARGE LOW PRESSURE TROUGH HOLDS OVER THE EASTERN HALF OF THE COUNTRY. PASSING UPPER LEVEL DISTURBANCES WILL HELP PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH FRIDAY NIGHT/... AS OF 935 PM THURSDAY... THE LAST CLUSTER OF ORGANIZED CONVECTION CONTINUES MOVING TO THE ESE OVER THE SRN PIEDMONT AND SW SANDHILLS. OTHER MORE ISOLATED CELLS ELSEWHERE HAVE BECOME STRONG BUT THEIR HIGH-REFLECTIVITY CORES HAVE NOT QUITE REACHED THE HEIGHTS OF EARLIER STORMS. THE BOUNDARY LAYER CONTINUES TO SLOWLY BUT STEADILY STABILIZE WITH MLCAPE DOWN TO 1500 J/KG AND GROWING CINH... AND THIS TREND SHOULD CONTINUE WITH STORMS DISSIPATING IN THE NEXT FEW HOURS. THE LATEST COUPLE OF HRRR RUNS AS WELL AS THE SREF AND WRF SUPPORT THIS SCENARIO WITH REMAINING STORMS SHIFTING TO OUR EAST AND WEAKENING. DYNAMIC SUPPORT FOR ASCENT WILL BE WANING AS THE VORTICITY AXIS SHIFTS TO OUR EAST... LEAVING BEHIND BAGGY MID LEVEL TROUGHING OVERNIGHT WITH A LINGERING DIFFUSE TROUGH AT THE SURFACE THROUGH THE CENTRAL CAROLINAS. WILL HOLD ONTO EXISTING FORECAST TREND OF POPS DECREASING WEST TO EAST. EXPECT FAIR TO PARTLY CLOUDY SKIES OVERNIGHT... ALTHOUGH THE MORE WIDESPREAD SHOWERS/STORMS IN THE EAST ALONG WITH SLIGHTLY HIGHER DEW POINTS AND 925-850 MB MOISTURE SHOULD YIELD MORE WIDESPREAD STRATUS IN OUR EAST. WITH THE RAIN-COOLED AIR IN SOME AREAS... CURRENT TEMPS HAVE FALLEN TO WITHIN A FEW DEGREES OF THE DEW POINT AND HENCE ARE CLOSE TO THE NIGHTTIME LOWS. CURRENT TEMP TRENDS PLUS STATISTICAL GUIDANCE SUPPORT LOWS CLOSE TO THE CURRENT FORECAST OF 69-74. -GIH FRIDAY... SHORTWAVE ENERGY DIGGING THROUGH THE UPPER MIDWEST WILL CONTINUE TO DEEPEN THE UPPER LEVEL TROUGH DEVELOPING OVER THE EASTERN US. A SHARP PIEDMONT TROUGH WILL BE IN PLACE DURING THE DAY ON FRIDAY..WITH LITTLE CHANGE IN AIRMASS EXPECTED OUTSIDE OF SLIGHTLY LOWER DEWPOINTS IN THE WESTERN PIEDMONT. CYCLONIC FLOW ALOFT...ALBEIT WITHOUT A NOTABLE TRIGGER IN THE MODELS...AND MODEST INSTABILITY WILL ONCE AGAIN SUPPORT SCATTERED TO NUMEROUS THUNDERSTORMS DURING THE AFTERNOON. WHILE ITS POSSIBLE THAT COVERAGE MAY NOT BE AS GREAT AS THIS AFTERNOON...MID-LEVEL FLOW WILL BE STRONGER AND DEEP LAYER SHEAR IS PROGGED TO TO EXCEED 30KT...SUGGESTING MULTICELLULAR ORGANIZATION. THE CURRENT SPC DAY TWO OUTLOOK INCLUDES ALL OF CENTRAL NC IN A SLIGHT RISK. REGARDING HIGH TEMPS...GUIDANCE ALMOST UNANIMOUSLY GIVES VALUES A FEW DEGREES WARM THAN TODAY...WITH LOWER 90S ACROSS A LARGE PORTION OF THE CWA. THIS WILL LIKELY LEAD TO HEAT INDICES NEAR 100 ACROSS THE SANDHILLS AND SOUTHERN PIEDMONT WHERE DEWPOINTS SHOULD HOVER IN THE LOWER 70S. FRIDAY NIGHT... WILL CONTINUE AT LEAST A SLIGHT CHANCE OF SHOWERS AND STORMS THROUGH FRIDAY NIGHT AS HEIGHTS CONTINUE TO SLOWLY FALL ALOFT AND THE AIRMASS OVER NC REMAINS HUMID. LOWS IN THE UPPER 60S AND LOWER 70S. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM THURSDAY... AN ANOMALOUSLY AMPLIFIED PATTERN WILL PREVAIL ACROSS THE CONUS THROUGH THE WEEKEND...CHARACTERIZED BY A DEEP UPPER LEVEL RIDGE OVER THE ROCKIES/INTERMOUNTAIN WEST AND DEEP TROUGHING EAST OF THE MISSISSIPPI...WITH A PERSISTENT UPPER LEVEL LOW CENTERED IN VICINITY OF THE LOWER GREAT LAKES AND OH VALLEY. ACROSS THE CAROLINAS AND MID-ATLANTIC...EXPECT ATYPICALLY STRONG SOUTHWEST FLOW ALOFT WITH NUMEROUS SMALL AMPLITUDE SHORTWAVES CROSSING THE REGION THROUGHOUT THE PERIOD IN THE PRESENCE OF A SEASONABLY MOIST AIRMASS. AS A RESULT...EXPECT ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS AND SLIGHTLY BELOW NORMAL HIGH TEMPS IN THE MID 80S...DEPENDING ON CLOUD COVER AND CONVECTION. THE EXACT COVERAGE AND PERSISTENCE OF CONVECTION WILL HIGHLY DEPEND ON THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT AND THE TIMING OF THESE DISTURBANCES IN RELATION TO THE DIURNAL HEATING CYCLE. FURTHERMORE...THE DEGREE OF DIURNAL DESTABILIZATION IS DIFFICULT TO ASCERTAIN GIVEN INCREASED CLOUD COVER AND AN ABOVE NORMAL CHANCE FOR NOCTURNAL OR EARLY MORNING CONVECTION...THOUGH ONE WOULD EXPECT AT LEAST SOME CLOUD BREAKS AND AREAS OF RELATIVELY STRONGER INSOLATION DURING PEAK HEATING. EITHER WAY...SLIGHTLY STEEPER MID-LEVEL LAPSE RATES /COOLER TEMPS ALOFT/ IN ASSOCIATION WITH THE UNUSUALLY AMPLIFIED UPPER LEVEL TROUGH OVER THE REGION WILL AT LEAST SOMEWHAT COMPENSATE FOR DECREASED INSOLATION. GIVEN DEEP-LAYER (0-6 KM) SHEAR LIKELY IN THE 35-45 KT RANGE...ORGANIZED CONVECTION WILL CERTAINLY BE POSSIBLE... INCLUDING SUPERCELLS...THOUGH THE TYPE/EXTENT OF ANY SEVERE THREAT CANNOT BE PRECISELY IDENTIFIED AT THIS TIME. IN ADDITION TO A POTENTIAL FOR SEVERE THUNDERSTORMS...ISOLATED FLASH FLOODING WILL ALSO BE POSSIBLE GIVEN RECENT HEAVY RAINFALL AND ABOVE NORMAL CHANCES FOR CONVECTION THROUGH THE WEEKEND. -VINCENT && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 PM THURSDAY... AN UNSEASONABLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST ACROSS THE CONUS THROUGH THE MIDDLE OF NEXT WEEK...CHARACTERIZED BY RIDGING OVER THE INTERMOUNTAIN WEST...TROUGHING CENTERED IN VICINITY OF THE MS RIVER VALLEY AND ATYPICALLY STRONG SW FLOW ALOFT OVER THE CAROLINAS. NUMEROUS SMALL AMPLITUDE DISTURBANCES IN THE PRESENCE OF ABOVE NORMAL MOISTURE (PWAT ~2.00") WILL RESULT IN ABOVE NORMAL CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH EARLY/MID NEXT WEEK... MODULATED PRIMARILY BY THE DIURNAL HEATING CYCLE...IN ADDITION TO A CONTINUED THREAT FOR SEVERE WEATHER (GIVEN FAVORABLE DEEP-LAYER SHEAR) AND ISOLD FLASH FLOODING. IN GENERAL EXPECT HIGHS SEVERAL DEGREES BELOW NORMAL DUE TO INCREASED CLOUD COVER AND CHANCES FOR CONVECTION. -VINCENT && .AVIATION /06Z THURSDAY THROUGH TUESDAY/... AS OF 145 AM FRIDAY... UPPER S/W VORT DISTURBANCE AND ASSOCIATED CONVECTION WILL EXIT THE SANDHILLS AND SOUTHERN COASTAL COUNTIES BY 08Z WITH SUBSIDENCE IN THE WAKE OF THE UPPER DISTURBANCE ALLOWING FOR DRY CONDITIONS FOR THE SECOND PART OF THE NIGHT. PATCHY SUB-VFR STRATUS AND/OR FOG IS POSSIBLE AROUND DAYBREAK...PARTICULARLY IN AREAS THAT SAW HEAVY RAIN THIS PAST EVENING. ANY STRATUS/FOG SHOULD LIFT BY 15Z THIS MORNING... WITH PREDOMINATELY VFR CONDITIONS INTO THE EARLY AFTERNOON BEFORE ANOTHER ROUND OF SCATTERED TO NUMEROUS STORMS ARE EXPECTED OVER CENTRAL NC. LOOKING BEYOND FRIDAY...THE WEATHER PATTERN WILL CHANGE VERY LITTLE THE NEXT SEVERAL DAYS. AN UNSEASONABLY STRONG LOW PRESSURE TROUGH COMBINED WITH A WARM AND UNSTABLE AIR WILL RESULT IN SCATTER TO NUMEROUS SHOWERS AND STORMS EACH AFTERNOON/EARLY EVENING... AND THE POTENTIAL FOR STRATUS OR FOG EACH MORNING. && .EQUIPMENT... KRAX WSR-88D WILL BE REMAIN DOWN OR IN DEGRADED MODE THROUGH FRIDAY MORNING. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE... AND IS WORKING TO RETURN THE RADAR TO NORMAL SERVICE BY EARLY AFTERNOON FRIDAY. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BLS SHORT TERM...VINCENT LONG TERM...VINCENT AVIATION...CBL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
351 AM CDT FRI JUN 28 2013 .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 CHALLENGES INCLUDE CLOUD COVER/PRECIPITATION CHANCES TODAY AND THEN TEMPERATURES THROUGH THE PERIOD. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT...BUT WILL LEAN ON LATEST RAP GUIDANCE FOR NEAR TERM FORECAST. FOR TODAY...STRATOCUMULUS DECK ACROSS NORTH-CENTRAL MN WILL EXPAND SOUTH AND WEST THROUGH THE DAY GIVEN CONVECTIVE TEMPERATURES IN THE UPPER 60S TO MID 70S. WITH A 100 KT 300 HPA JET STREAK MOVING THROUGH NORTHWEST FLOW ALOFT AND 500 TO 1000 J/KG OF MLCAPE... SOME OF THESE THERMAL CU MAY GIVE WAY TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS. REMOVED POPS ALONG AND WEST OF THE VALLEY THIS MORNING WITH A MOSTLY SUNNY START TO THE DAY...BUT WILL EXPAND CHANCE POPS SOUTH AND WEST WITH INCREASING CLOUD COVER THIS AFTERNOON. BOUNDARY LAYER IS 3 TO 6 C COLDER THAN YESTERDAY... SO EXPECT DAYTIME HIGHS IN THE 70S. WITH 20 TO 30 KTS AT 850 HPA TO MIX TO THE SURFACE...EXPECT ANOTHER BREEZY AFTERNOON WITH WINDS FROM 15 TO 20 MPH AND OCCASIONAL GUSTS UP TO 30 MPH. THERMAL CU WILL DISSIPATE AFTER SUNSET...BUT EXPECT SOME THICKER CLOUD COVER TO TAKE ITS TIME MOVING OUT OF THE REGION OVERNIGHT. WINDS WILL SUBSIDE WITH SURFACE HIGH PRESSURE BUILDING ACROSS THE REGION. OVERNIGHT LOWS WILL BE IN THE 50S. MOST OF SATURDAY WILL BE DRY...BUT DID KEEP 20 POPS REGION-WIDE THROUGH THE DAY AS OPERATIONAL MODELS PAINT SEEMINGLY RANDOM LIGHT QPF IN ASSOCIATION WITH A WEAK SHORT-WAVE ALOFT. SURFACE TO MID- LEVEL FORCING IS WEAK...SO EXPECT MINIMAL ACCUMULATION WITH ANY SHOWERS THAT DO DEVELOP. ANOTHER COOLER DAY WITH HIGHS AGAIN IN THE 70S. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 SURFACE PRESSURE RIDGE WILL SLIDE SLOWLY ACROSS THE NORTHERN PLAINS SUNDAY AND MONDAY RESULTING IN DRY...MOSTLY SUNNY CONDITIONS. WINDS WILL BE LIGHT AND TEMPERATURES WILL BE NEAR SEASONAL NORMALS WITH HIGHS IN THE UPPER 70S TO LOWER 80S. A BLEND OF THE GFS/ECMWF TO BE FOLLOWED EARLY IN THE EXTENDED THEN TRENDING TOWARD THE GFS IN DAYS 5-7. THE UPPER PATTERN AMPLIFIES DURING THE PERIOD WITH RIDGING OVER THE WRN CONUS AND TROF OVER THE ERN THIRD OF THE COUNTRY. THE RIDGING OUT WEST WILL RETROGRADE SOMEWHAT WEST ALLOWING FOR PIECES OF S/WV ENERGY TO SLIDE DOWN THE BACK SIDE OF THE TROF BY TUE/TUE NIGHT. A FRONTAL BOUNDARY ACROSS THE REGION WILL HELP FOCUS PRECIPITATION TUE-THU WITH WED BEING THE MOST OPTIMAL PERIOD FOR SCATTERED SHRA/TSRA. THE BOUNDARY IS EXPECTED TO WEAKEN BY THU. TEMPERATURES WILL BE TEMPERED WITH HIGHS IN THE UPPER 70S TO AROUND 80 THROUGH THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1142 PM CDT THU JUN 27 2013 VFR CONDITIONS MOST AREAS THIS FORECAST PERIOD. EXPECT VFR CIGS TO DEVELOP BY MID MORNING TOMORROW GRADUALLY THINNING DURING THE AFTERNOON. NE FA MAY INITIALLY DEVELOP MVFR CIGS BECMG VFR IN THE AFTERNOON. WILL AGAIN SEE SOME SHRA DEVELOPING. && .HYDROLOGY... ISSUED AT 930 PM CDT THU JUN 27 2013 RUNOFF CONTINUES TO MAKE ITS WAY INTO THE RED RIVER FROM AREA TRIBUTARIES. TRENDS CONTINUE TO BE ON TARGET FROM THE MORNING FORECAST UPDATE FOR THE RIVER POINTS. THE RED RIVER AT FARGO IS STILL FORECAST TO CREST NEAR MAJOR FLOOD STAGE TOWARDS LATE TODAY OR TONIGHT. OTHERWISE...RISES ARE EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS ON CENTRAL AND NORTHERN SECTIONS OF THE RED...WITH A FEW FORECAST POINTS EXPECTED TO RISE ABOVE MINOR FLOOD STAGE. WAHPETON REMAINS BELOW FLOOD STAGE AND IS ANTICIPATED TO CONTINUE FALLING. HOWEVER...EXPECTED RELEASES FROM WHITE ROCK DAM MAY SLOW THE RECESSION OF RIVER LEVELS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...ROGERS LONG TERM...ROGERS/FRAZIER AVIATION...VOELKER HYDROLOGY...HOPKINS
AREA FORECAST DISCUSSION...UPDATED
NWS PENDLETON OR
1032 AM PDT WED JUN 26 2013 UPDATED AVIATION DISCUSSION .SHORT TERM... QUICK UPDATE TO THE FORECAST TO INCREASE CLOUDS AND CHANCES OF PRECIPITATION FOR THIS AFTERNOON. SATELLITE IMAGERY SHOWS THE PLUME OF PACIFIC MOISTURE STARTING TO BEND BACK TO THE NORTH AS THE WESTERN US RIDGE BEGINS TO BUILD. A SHORT WAVE IN THIS SOUTHWESTERLY FLOW IS CAUSING WARM ADVECTION WIDESPREAD CLOUDS TO FORM OVER THE AREA. VISIBLE SATELLITE IMAGERY DOESN`T SHOW MUCH HOPE OF SUNSHINE TODAY. THIS WILL LIMIT THE INSTABILITY OVER THE AREA DESPITE THE ABUNDANT MOISTURE. THUS THERE`S NO THUNDER IN THE FORECAST FOR NOW BUT WILL HAVE TO MONITOR THIS, ESPECIALLY OVER CENTRAL OREGON WHERE THE SUN HAS THE BEST CHANCE OF BREAKING THROUGH THE CLOUDS. THE HRRR MODEL DOES SHOW SOME LIGHT SHOWERS ASSOCIATED WITH THIS CLOUD BAND, EVEN OVER THE LOWER BASIN AREA. BUT ALL MODELS AGREE ON A FAIRLY SHOWERY DAY OVER THE MOUNTAINS. SO I INCREASED PRECIPITATION CHANCES OVER THE ENTIRE AREA FOR THIS AFTERNOON. RJ && .AVIATION...18Z TAFS...VFR CONDITIONS WILL BE PREVALENT THROUGH THURSDAY MORNING. LIGHT SHOWERS WILL CONTINUE ACROSS THE AREA THROUGH AROUND 03Z THIS EVENING AFFECTING ALL TAF SITES WITH VCSH OR -SHRA EXCEPT KYKM WHICH IS EXPECTED TO REMAIN DRY. DO NOT EXPECT ANY THUNDERSTORMS TO DEVELOP TODAY. WHILE SHOWERS MAY CREATE BRIEF MVFR CONDITIONS THIS AFTERNOON, CEILINGS WILL GENERALLY BE BKN-OVC AT 4000-8000 FEET THROUGH 08Z THEN BECOMING SCT-BKN ABOVE 6000 FEET AGL. SURFACE WINDS ARE EXPECTED TO REMAIN BELOW 15 KTS FOR THE NEXT 24 HOURS. PERRY && .PREV DISCUSSION... /ISSUED 317 AM PDT WED JUN 26 2013/ SHORT TERM...TODAY THROUGH THURSDAY NIGHT...ANIMATED WATER VAPOR SATELLITE IMAGERY SHOWS A LARGE MID/UPPER LEVEL LOW PRESSURE SYSTEM NEAR 49N/138W WITH AN UPPER LEVEL JET STREAM ON THE SOUTHERN FLANK OF THE LOW FEEDING ASSOCIATED SUBTROPICAL MOISTURE TOWARD THE PACIFIC NORTHWEST. WIND SPEEDS IN THE CORE OF THE JET STREAM AROUND 30000 FEET ARE 125-130 MPH WITH THE NOSE OF THE JET CURRENTLY LOCATED SQUARELY OVER THE FORECAST AREA. SOUTHWEST FLOW ALOFT ASSOCIATED WITH THE JET STREAM WILL STEER A DISTURBANCE NOW MAKING LANDFALL ON THE OREGON COAST ACROSS THE REGION TODAY AND BRING ISOLATED TO SCATTERED SHOWERS THROUGH THIS AFTERNOON TO THE MOUNTAINS OF SE WASHINGTON AND NE OREGON, THE FOOTHILLS OF THE BLUE MOUNTAINS, AND THE EAST SLOPES OF THE CASCADES. THE DISTURBANCE EXITS INTO IDAHO/MONTANA THIS EVENING FOR DRY CONDITIONS AT LOWER ELEVATIONS AND DECREASING POPS IN THE BLUE MOUNTAINS AND ALONG THE CASCADE CRESTS TONIGHT. HEIGHT CONTOURS OF PRESSURE SURFACES IN THE TROPOSPHERE BEGIN RISING ON THURSDAY INTO FRIDAY BY VIRTUE OF A MID/UPPER LEVEL RIDGE OF HIGH PRESSURE THAT BUILDS OVER THE PACIFIC NORTHWEST THROUGH THE WEEKEND WITH THE RIDGE AMPLIFICATION CONTINUING DIRECTLY OVER THE FORECAST AREA INTO NEXT WEEK. SINKING AIR ASSOCIATED WITH THE RIDGE WILL INITIATE A STRONG WARMING TREND TODAY, WHICH WILL PERSIST OVER THE WEEKEND AND WELL INTO NEXT WEEK THUS PRODUCING WELL ABOVE NORMAL HIGH TEMPERATURES EACH DAY. POLAN LONG TERM...FRIDAY THROUGH WEDNESDAY...ALL MODELS ARE IN AGREEMENT IN CONTINUING TO BUILD A STRONG RIDGE OF HIGH PRESSURE INTO THE PACIFIC NORTHWEST FROM THE GREAT BASIN. CONFIDENCE OF THIS PATTERN DEVELOPING IS INCREASING AS EACH MODEL RUN CONTINUES TO SHOW THE IT DEVELOPING. THIS WILL RESULT IN A HEAT WAVE DURING THE EXTENDED FORECAST PERIOD. EACH DAY WILL BECOME HOTTER THAN THE PREVIOUS FROM FRIDAY THROUGH WEDNESDAY AS 850 MB TEMPERATURES BECOME WARMER EACH DAY FROM THE PREVIOUS DAY AND THE CENTER OF THE HIGH PRESSURE RIDGE BECOMING WELL ESTABLISHED OVER THE PACIFIC NORTHWEST. ON FRIDAY CAN EXPECT HIGH TEMPERATURES TO CLIMB INTO THE LOWER TO MID 90S IN THE LOWER ELEVATIONS...WITH UPPER 70S TO MID 80S IN THE MOUNTAINS. THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND INTO EARLY NEXT WEEK. BY TUESDAY 850 MB TEMPERATURES ARE INDICATING MAXIMUM SURFACE TEMPERATURES TO BE WELL INTO THE MID 90S TO MID 100S...WITH MID 80S TO MID 90S IN THE MOUNTAINS. THE GFS MODEL IS FORECASTING AN 850 MB TEMPERATURE OF 31 OVER PENDLETON ON TUESDAY WHICH WHEN TRANSLATED TO THE SURFACE IS A TEMPERATURE NEAR 110. HOWEVER...IT IS A BIT TOO EARLY TO BELIEVE THE MODEL THAT FAR OUT IN TIME...BUT NEVERTHELESS CONFIDENCE IS INCREASING THAT IT WILL BECOME DANGEROUSLY HOT BY MONDAY THROUGH WEDNESDAY. THE HOT SURFACE TEMPERATURES WILL CREATE STEEP LAPSE RATES. THERE MAY BE ENOUGH MID LEVEL MOISTURE AS WELL SUCH THAT ISOLATED AFTERNOON AND EVENING THUNDERSTORMS COULD DEVELOP BEGINNING FRIDAY AFTERNOON...MAINLY ALONG THE WASHINGTON CASCADES AND THE EASTERN OREGON/SOUTHEAST WASHINGTON MOUNTAINS. 88 && .PRELIMINARY POINT TEMPS/POPS... PDT 77 56 88 60 / 30 20 0 0 ALW 78 60 89 64 / 30 20 0 0 PSC 81 58 89 63 / 20 10 0 0 YKM 79 57 85 62 / 20 10 0 0 HRI 81 57 89 61 / 20 10 0 0 ELN 76 55 85 60 / 30 10 0 0 RDM 75 50 86 52 / 20 10 0 0 LGD 72 52 84 54 / 70 10 0 0 GCD 76 53 87 56 / 60 10 0 0 DLS 79 59 87 61 / 20 10 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. && THREAT INDEX TODAY : GREEN THURSDAY : GREEN FRIDAY : GREEN GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES. YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT. RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT. FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT... WWW.WEATHER.GOV/PENDLETON $$ 99/99/99
AREA FORECAST DISCUSSION
NWS PENDLETON OR
ISSUED BY NATIONAL WEATHER SERVICE SPOKANE WA 814 AM PDT WED JUN 26 2013 .SHORT TERM... QUICK UPDATE TO THE FORECAST TO INCREASE CLOUDS AND CHANCES OF PRECIPITATION FOR THIS AFTERNOON. SATELLITE IMAGERY SHOWS THE PLUME OF PACIFIC MOISTURE STARTING TO BEND BACK TO THE NORTH AS THE WESTERN US RIDGE BEGINS TO BUILD. A SHORT WAVE IN THIS SOUTHWESTERLY FLOW IS CAUSING WARM ADVECTION WIDESPREAD CLOUDS TO FORM OVER THE AREA. VISIBLE SATELLITE IMAGERY DOESN`T SHOW MUCH HOPE OF SUNSHINE TODAY. THIS WILL LIMIT THE INSTABILITY OVER THE AREA DESPITE THE ABUNDANT MOISTURE. THUS THERE`S NO THUNDER IN THE FORECAST FOR NOW BUT WILL HAVE TO MONITOR THIS, ESPECIALLY OVER CENTRAL OREGON WHERE THE SUN HAS THE BEST CHANCE OF BREAKING THROUGH THE CLOUDS. THE HRRR MODEL DOES SHOW SOME LIGHT SHOWERS ASSOCIATED WITH THIS CLOUD BAND, EVEN OVER THE LOWER BASIN AREA. BUT ALL MODELS AGREE ON A FAIRLY SHOWERY DAY OVER THE MOUNTAINS. SO I INCREASED PRECIPITATION CHANCES OVER THE ENTIRE AREA FOR THIS AFTERNOON. RJ && .AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY AND WEDNESDAY NIGHT AT ALL TAF SITES. THERE WILL BE ISOLATED TO SCATTERED SHOWERS AS ANOTHER WEATHER DISTURBANCE MOVES ACROSS THE REGION. HOWEVER...IT IS UNLIKELY THAT CONDITIONS WILL DROP TO MVFR EXCEPT FOR VERY BRIEF TIMES AT KRDM AND/OR KBDN DUE TO LOWERED CEILINGS AND/OR VISIBILITY IF A SHOWER OR A THUNDERSTORM MOVES DIRECTLY OVER EITHER OF THOSE SITES. WINDS WILL REMAIN LIGHT AND UNDER 15 KTS THROUGH TONIGHT...EXCEPT GUSTY AND ERRATIC NEAR ANY SHOWERS OR THUNDERSTORMS THAT MAY DEVELOP. 88 && .PREV DISCUSSION... /ISSUED 317 AM PDT WED JUN 26 2013/ SHORT TERM...TODAY THROUGH THURSDAY NIGHT...ANIMATED WATER VAPOR SATELLITE IMAGERY SHOWS A LARGE MID/UPPER LEVEL LOW PRESSURE SYSTEM NEAR 49N/138W WITH AN UPPER LEVEL JET STREAM ON THE SOUTHERN FLANK OF THE LOW FEEDING ASSOCIATED SUBTROPICAL MOISTURE TOWARD THE PACIFIC NORTHWEST. WIND SPEEDS IN THE CORE OF THE JET STREAM AROUND 30000 FEET ARE 125-130 MPH WITH THE NOSE OF THE JET CURRENTLY LOCATED SQUARELY OVER THE FORECAST AREA. SOUTHWEST FLOW ALOFT ASSOCIATED WITH THE JET STREAM WILL STEER A DISTURBANCE NOW MAKING LANDFALL ON THE OREGON COAST ACROSS THE REGION TODAY AND BRING ISOLATED TO SCATTERED SHOWERS THROUGH THIS AFTERNOON TO THE MOUNTAINS OF SE WASHINGTON AND NE OREGON, THE FOOTHILLS OF THE BLUE MOUNTAINS, AND THE EAST SLOPES OF THE CASCADES. THE DISTURBANCE EXITS INTO IDAHO/MONTANA THIS EVENING FOR DRY CONDITIONS AT LOWER ELEVATIONS AND DECREASING POPS IN THE BLUE MOUNTAINS AND ALONG THE CASCADE CRESTS TONIGHT. HEIGHT CONTOURS OF PRESSURE SURFACES IN THE TROPOSPHERE BEGIN RISING ON THURSDAY INTO FRIDAY BY VIRTUE OF A MID/UPPER LEVEL RIDGE OF HIGH PRESSURE THAT BUILDS OVER THE PACIFIC NORTHWEST THROUGH THE WEEKEND WITH THE RIDGE AMPLIFICATION CONTINUING DIRECTLY OVER THE FORECAST AREA INTO NEXT WEEK. SINKING AIR ASSOCIATED WITH THE RIDGE WILL INITIATE A STRONG WARMING TREND TODAY, WHICH WILL PERSIST OVER THE WEEKEND AND WELL INTO NEXT WEEK THUS PRODUCING WELL ABOVE NORMAL HIGH TEMPERATURES EACH DAY. POLAN LONG TERM...FRIDAY THROUGH WEDNESDAY...ALL MODELS ARE IN AGREEMENT IN CONTINUING TO BUILD A STRONG RIDGE OF HIGH PRESSURE INTO THE PACIFIC NORTHWEST FROM THE GREAT BASIN. CONFIDENCE OF THIS PATTERN DEVELOPING IS INCREASING AS EACH MODEL RUN CONTINUES TO SHOW THE IT DEVELOPING. THIS WILL RESULT IN A HEAT WAVE DURING THE EXTENDED FORECAST PERIOD. EACH DAY WILL BECOME HOTTER THAN THE PREVIOUS FROM FRIDAY THROUGH WEDNESDAY AS 850 MB TEMPERATURES BECOME WARMER EACH DAY FROM THE PREVIOUS DAY AND THE CENTER OF THE HIGH PRESSURE RIDGE BECOMING WELL ESTABLISHED OVER THE PACIFIC NORTHWEST. ON FRIDAY CAN EXPECT HIGH TEMPERATURES TO CLIMB INTO THE LOWER TO MID 90S IN THE LOWER ELEVATIONS...WITH UPPER 70S TO MID 80S IN THE MOUNTAINS. THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND INTO EARLY NEXT WEEK. BY TUESDAY 850 MB TEMPERATURES ARE INDICATING MAXIMUM SURFACE TEMPERATURES TO BE WELL INTO THE MID 90S TO MID 100S...WITH MID 80S TO MID 90S IN THE MOUNTAINS. THE GFS MODEL IS FORECASTING AN 850 MB TEMPERATURE OF 31 OVER PENDLETON ON TUESDAY WHICH WHEN TRANSLATED TO THE SURFACE IS A TEMPERATURE NEAR 110. HOWEVER...IT IS A BIT TOO EARLY TO BELIEVE THE MODEL THAT FAR OUT IN TIME...BUT NEVERTHELESS CONFIDENCE IS INCREASING THAT IT WILL BECOME DANGEROUSLY HOT BY MONDAY THROUGH WEDNESDAY. THE HOT SURFACE TEMPERATURES WILL CREATE STEEP LAPSE RATES. THERE MAY BE ENOUGH MID LEVEL MOISTURE AS WELL SUCH THAT ISOLATED AFTERNOON AND EVENING THUNDERSTORMS COULD DEVELOP BEGINNING FRIDAY AFTERNOON...MAINLY ALONG THE WASHINGTON CASCADES AND THE EASTERN OREGON/SOUTHEAST WASHINGTON MOUNTAINS. 88 AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY AND WEDNESDAY NIGHT AT ALL TAF SITES. THERE WILL BE ISOLATED TO SCATTERED SHOWERS AS ANOTHER WEATHER DISTURBANCE MOVES ACROSS THE REGION. HOWEVER...IT IS UNLIKELY THAT CONDITIONS WILL DROP TO MVFR EXCEPT FOR VERY BRIEF TIMES AT KRDM AND/OR KBDN DUE TO LOWERED CEILINGS AND/OR VISIBILITY IF A SHOWER OR A THUNDERSTORM MOVES DIRECTLY OVER EITHER OF THOSE SITES. WINDS WILL REMAIN LIGHT AND UNDER 15 KTS THROUGH TONIGHT...EXCEPT GUSTY AND ERRATIC NEAR ANY SHOWERS OR THUNDERSTORMS THAT MAY DEVELOP. 88 && .PRELIMINARY POINT TEMPS/POPS... PDT 77 56 88 60 / 30 20 0 0 ALW 78 60 89 64 / 30 20 0 0 PSC 81 58 89 63 / 20 10 0 0 YKM 79 57 85 62 / 20 10 0 0 HRI 81 57 89 61 / 20 10 0 0 ELN 76 55 85 60 / 30 10 0 0 RDM 75 50 86 52 / 20 10 0 0 LGD 72 52 84 54 / 70 10 0 0 GCD 76 53 87 56 / 60 10 0 0 DLS 79 59 87 61 / 20 10 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. && THREAT INDEX TODAY : GREEN THURSDAY : GREEN FRIDAY : GREEN GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES. YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT. RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT. FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT... WWW.WEATHER.GOV/PENDLETON $$ 99/99/99
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
433 AM CDT FRI JUN 28 2013 .DISCUSSION... A STRONG UPPER LEVEL RIDGE OF HIGH PRESSURE IS CENTERED OVER SOUTHERN UTAH WITH THE RIDGE EASTWARD INTO EAST TEXAS. 850 MB TEMPS CONTINUE TO WARM WITH KCRP NOW UP TO 22 C AND KLCH NOW UP TO 20 C. 700 MB TEMPS ALSO CONTINUE TO WARM AND ARE NOW UP TO 13 C. MAX TEMPS TODAY WILL PROBABLY BE 2-3 DEGREES WARMER THAN YESTERDAY. NAM 12 STILL HINTING THAT A SEA BREEZE CIRCULATION WILL DEVELOP AND FEEL THIS WILL HINDER THE TEMPERATURE RISE AT COASTAL SITES TODAY. THERE WILL BE MORE OF AN OFFSHORE FLOW ON SATURDAY AND FEEL COASTAL SITES COULD GET PLENTY WARM AT THAT TIME. A WEAK BOUNDARY WILL APPROACH THE EXTREME NORTH PART OF SE TX THIS EVENING AND STALL. THE 4 KM WRF...THE RAP AND 06Z NAM 12 ARE NOW DEVELOPING SOME PCPN ALONG THE BOUNDARY. WILL SOMEWHAT RELUCTANTLY ADD 20 POPS OVER THE EXTREME NORTH FROM 00-06Z. THE BOUNDARY WILL CROSS SE TX ON SATURDAY WITH 500 HEIGHTS SLOWLY DROPPING. FEEL A WARM START AND DRIER AIR ADVECTING INTO THE REGION WILL COMPENSATE FOR THE LOWER HEIGHTS SO WILL MAINTAIN VERY WARM TEMPS FOR SAT AFTN. A S/WV WILL MOVE SE ON THE PERIPHERY OF THE UPPER RIDGE LATE SAT NITE INTO SUNDAY. THE TEXAS TECH WRF SHOWS A SWATH OF PCPN DEVELOPING IN THE NW FLOW AND MOVING INTO THE AREA BETWEEN 06-12Z SUNDAY. ADDED 20 POPS FOR THIS POTENTIAL ON SAT NIGHT. DRIER LOW LEVEL AIR WILL ALLOW MIN TEMPS TO TREND SLIGHTLY COOLER SUNDAY MORNING AND LOWER HEIGHTS WILL PORTEND COOLER MAX TEMPS ON SUNDAY AFTN. THE UPPER RIDGE RETREATS WEST ON SUNDAY AND BEYOND AS AN UPPER LEVEL TROUGH OVER THE EASTERN U.S. RETROGRADES WEST. HEIGHTS WILL LOWER OVER SE TX WITH A SUBTLE DECREASE IN AFTERNOON TEMPS EXPECTED. THE AIR MASS WILL BE RATHER DRY SO AM STILL EXPECTING MAX TEMPS TO WARM INTO THE MIDDLE 90S. MOISTURE LEVELS BEGIN TO DEEPEN ON WEDNESDAY SO AM EXPECTING AN INCREASE IN CLOUD COVER AND HIGHER RAIN CHANCES. THE UPPER LEVEL TROUGH WILL LINGER ACROSS THE CENTRAL PLAINS THROUGH THE END OF NEXT WEEK. WILL CARRY RAIN CHANCES...ADDITIONAL CLOUD COVER AND COOLER TEMPS IN RESPONSE TO THE UPPER TROUGH. 43 && .MARINE... LIGHT TO MODERATE WIND SPEEDS WILL REMAIN THROUGH THE AFTERNOON. WINDS SHOULD THEN BECOME MODERATE AND APPROACH SCEC CRITERIA LATE FRIDAY INTO EARLY SATURDAY AS THE THERMAL GRADIENT INCREASES ALONG WITH THE BOUNDARY MOVING SOUTHWARDS. THE BOUNDARY SHOULD THEN STALL OUT NEAR THE COAST ON SATURDAY THEN HAVE THE WINDS BRIEFLY SWITCH TO THE NORTH AS A SECONDARY BOUNDARY MARCHES SOUTHWARD. THE BOUNDARY SHOULD THEN WASH OUT AND PULL NORTHWARDS EARLY WEDNESDAY GIVING WAY TO ONSHORE WINDS. 23 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 102 75 102 72 96 / 0 10 10 20 20 HOUSTON (IAH) 100 76 100 75 97 / 0 10 10 20 20 GALVESTON (GLS) 94 80 97 78 96 / 10 10 10 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43/23
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1119 PM CDT THU JUN 27 2013 .AVIATION... ONLY MINOR CHANGES TO FORECAST. HAVE SPED UP FROPA A COUPLE OF HOURS BASED ON NEW MOS. ALTHOUGH THERE IS LITTLE UPPER SUPPORT...THE LIFT ALONG THE FRONT MAY PRODUCE ISOLATED TSRA TOMORROW AFTERNOON GIVEN THAT HIGH TEMPERATURES ARE EXPECTED TO BE IN THE TRIPLE DIGITS. TSRA PROBABILITIES CONTINUE TO LOOK TOO LOW TO MENTION IN TAFS AND EARLIER FROPA ALSO LOWERS POP CHANCES IN METROPLEX. AT WACO...FROPA FORECAST FOR ABOUT 21Z/3PM. 84 && .UPDATE... THE THUNDERSTORM COMPLEX THAT EXTENDS FROM NORTHEASTERN KANSAS SOUTHWEST THROUGH CENTRAL OKLAHOMA WEST INTO THE TEXAS PANHANDLE CONTINUES TO MOVE SOUTHWARD THIS EVENING. A DECENT OUTFLOW BOUNDARY IS APPARENT ON THE RADAR LOOPS THIS EVENING AHEAD OF THIS COMPLEX. THE THUNDERSTORM COMPLEX IS EXPECTED TO WEAKEN LATER THIS EVENING AND DISSIPATE BEFORE CROSSING THE RED RIVER OVERNIGHT. THE 18Z TEXAS TECH WRF IS NOT REPRESENTATIVE OF WHAT IS CURRENTLY HAPPENING. THE 00Z RUN OF THE NAM WHICH SEEMS TO BE UNDER-DOING WHAT IS CURRENTLY OCCURRING...ALSO INDICATES THAT THE COMPLEX SHOULD DISSIPATE BEFORE REACHING THE RED RIVER. THE HIGH RESOLUTION RAPID REFRESH AND THE RAP INDICATE THAT THE PART OF THE SYSTEM THAT WOULD AFFECT US ON ITS CURRENT TRACK WILL ALSO DISSIPATE BEFORE REACHING NORTH TEXAS. SOME HIGH CLOUDS FROM THIS ACTIVITY SPREAD INTO NORTH TEXAS LATER TONIGHT. AS FAR AS TOMORROW IS CONCERNED. IT STILL APPEARS THAT WE WILL HAVE A PRETTY HOT DAY WITH SOUTHWESTERLY SURFACE WINDS AHEAD OF THE WEAK COLD FRONT. WACO MAY COME CLOSE TO THEIR RECORD HIGH FOR JUNE 28TH WHICH IS 106 DEGREES SET IN 1980. THE RECORD HIGH FOR DFW FOR TOMORROW IS AN UNATTAINABLE /WE HOPE/ 112 DEGREES WHICH ALSO OCCURRED IN 1980. 58 && .PREV DISCUSSION... /ISSUED 343 PM CDT THU JUN 27 2013/ CHANGES ARE ON THE WAY FOR NORTH AND CENTRAL TEXAS BEGINNING TOMORROW. THROUGH THE WEEKEND...THE UPPER LEVEL RIDGE THAT HAS BEEN DOMINATING THE AREA WILL AMPLIFY OVER THE WESTERN CONUS WHILE AN UPPER LEVEL TROUGH DIGS DEEP OVER THE EASTERN HALF OF THE COUNTRY. THE INFLUENCE OF THE UPPER LEVEL RIDGE WILL GREATLY BE WEAKENED FROM THE DEEPENING TROUGH TO OUR EAST. OVERALL...THIS WILL RESULT IN COOLER TEMPERATURES AND SLIGHT CHANCES FOR RAIN OVER THE NEXT WEEK. EXPECT ANOTHER MOSTLY CLEAR AND WARM NIGHT TONIGHT WITH OVERNIGHT LOWS IN THE MID TO UPPER 70S...EXCEPT LOWER 80S IN THE DALLAS CITY AREA. FRIDAY IS EXPECTED TO BE AN OPPRESSIVELY HOT DAY ACROSS PART OF THE REGION DUE TO A COOL FRONT MOVING INTO THE AREA. THIS FRONT WILL BE THE FIRST OF TWO THAT INFLUENCES NORTH AND CENTRAL TEXAS THIS WEEKEND. SHARPLY WARMING TEMPERATURES ARE EXPECTED AHEAD OF TOMORROWS FRONT WITH TEMPERATURES SOARING BETWEEN 101-107 AHEAD OF THE FRONT. THE CHALLENGE IS THE SPEED AND TIMING OF THE FRONT. THE LOCATION OF THE FRONT WILL DETERMINE WHERE THE HOTTEST TEMPERATURES WILL OCCUR TOMORROW. MOST OF THE MODELS /INCLUDING SHORTER TERM HI-RES MODELS/ HAVE THE FRONT AROUND THE I-20 CORRIDOR ABOUT MID AFTERNOON TOMORROW. BASED ON THIS TIMING/LOCATION...KEPT HIGH TEMPERATURES NORTH OF I-20 IN THE MID TO UPPER 90S...CLOSE TO 100-101 NEAR THE I-20 CORRIDOR...AND THEN RANGING FROM 103-107 SOUTH OF THE I-20 CORRIDOR. IN ADDITION...ALSO INTRODUCED A MENTION OF ISOLATED THUNDERSTORMS OVER THE NORTHERN TWO-THIRDS OF THE REGION FRIDAY AFTERNOON AS SOME MODELS INDICATE ISOLATED CONVECTION MAY DEVELOP ALONG AND SLIGHTLY AHEAD OF THE FRONT. HOWEVER...FORECAST SOUNDINGS INDICATE THE LOWER LEVELS OF THE ATMOSPHERE WILL BE PRETTY DRY. THIS POINTS TO THE POTENTIAL FOR LOTS OF EVAPORATION/VIRGA FROM MID LEVEL CLOUDS/CONVECTION AND ALSO A THREAT FOR GUSTY WINDS WITH ANY CONVECTION THAT DOES MATERIALIZE. BEHIND TOMORROWS COOL FRONT...DRIER AIR WILL BEGIN TO FILTER INTO THE REGION WITH A BETTER PUSH OF DRY AIR ON SUNDAY BEHIND THE NEXT FRONT/REINFORCING FRONT. TEMPERATURES ON SATURDAY WILL STILL BE WARM RANGING FROM THE LOWER 90S IN THE NORTHEAST TO UPPER 90S/NEAR 100 DEGREES IN THE WEST AND SOUTHWEST. TEMPERATURES WILL FINALLY START TO DROP SATURDAY NIGHT AND THE REMAINDER OF THE FORECAST LOOKS TO BE GENERALLY BELOW NORMAL. THE LATEST SET OF MODEL RUNS INDICATE THAT THE AIR BEHIND SUNDAY/S FRONT WILL BE DRIER THAN PREVIOUS MODEL RUNS...WITH DEWPOINTS IN THE 50S AND LOWER 60S THROUGH AT LEAST MID WEEK. THIS WILL RESULT IN LOWER OVERNIGHT LOWS AND ALSO MORE PLEASANT DAYTIME HIGHS FOR THIS TIME OF YEAR. IN SUMMARY...OVERNIGHT LOWS WILL MOSTLY BE IN THE 60S AND OCCASIONALLY LOWER 70S...DAYTIME HIGHS WILL BE IN THE MID 80S TO LOWER 90S. IT IS ALSO GOING TO FEEL MUCH DRIER WITH LOWER HUMIDITY VALUES THANKS TO THE LOWER DEWPOINT TEMPERATURES. WHILE THERE ARE SOME CHANCES FOR RAIN THROUGH THE FORECAST PERIOD...THE BEST CHANCES FOR RAIN MAY ACTUALLY COME NEAR THE END OF THE FORECAST...NEAR THE JULY 4TH HOLIDAY. HAVE TAPERED BACK THE POPS FOR SATURDAY AS IT LOOKS LIKE THE RIDGE WILL HOLD STRONG OVER OUR WESTERN COUNTIES. THERE ARE STILL SLIGHT CHANCES FOR RAIN OVER THE REGION ON SUNDAY AS THE NEXT FRONT ARRIVES. WITH THE DRIER AIR EXPECTED BEHIND SUNDAY/S FRONT...RAIN CHANCES EARLY NEXT WEEK ARE SLIM BUT NOT COMPLETELY ZERO. WE WILL BE UNDER THE INFLUENCE OF NORTHERLY FLOW ALOFT BETWEEN THE UPPER TROUGH TO OUR EAST AND THE RIDGE TO OUR WEST. HOWEVER...IT/S DIFFICULT TO PIN POINT EXACTLY WHEN AND WHERE ISOLATED CONVECTION WILL OCCUR THIS PATTERN AND KEPT GHOST 10 POPS IN THE FORECAST. WE COULD HAVE ISOLATED AFTERNOON CONVECTION NEAR OR IN OUR FAR EASTERN ZONES...CLOSER TO THE UPPER LEVEL TROUGH. BY THE MIDDLE TO END OF NEXT WEEK...THE UPPER LEVEL TROUGH TO OUR EAST WILL EXPAND FARTHER WEST AND WE COULD SEE SOME DISTURBANCES CROSSING THE REGION. INTRODUCED 20 POPS FOR NOW ON WEDNESDAY AND THURSDAY OF NEXT WEEK. 82/JLD && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 78 102 76 98 72 / 0 10 5 10 10 WACO, TX 76 104 75 99 71 / 0 10 10 10 10 PARIS, TX 74 97 71 92 66 / 5 10 5 10 10 DENTON, TX 76 99 73 97 69 / 5 10 5 10 10 MCKINNEY, TX 75 99 72 96 69 / 0 10 5 10 10 DALLAS, TX 81 102 77 98 74 / 0 10 5 10 10 TERRELL, TX 76 101 74 96 70 / 0 10 5 10 10 CORSICANA, TX 76 105 75 98 71 / 0 10 10 10 10 TEMPLE, TX 74 103 75 99 71 / 0 10 10 10 10 MINERAL WELLS, TX 77 103 73 98 69 / 0 10 5 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1116 AM EDT FRI JUN 28 2013 .SYNOPSIS... A BROAD AREA OF LOW PRESSURE WILL REMAIN OVER THE NORTHEAST AND IMPACT THE REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE BERMUDA HIGH WILL STRENGTHEN AND BUILD BACK TOWARD THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CAPES ALREADY RUNNING 1500-2000 J/KG ACROSS MOST OF THE TRI-STATE AT 14Z PER LAPS ANALYSIS. HOWEVER CORE OF LOW LEVEL JET IS TO THE EAST...AND THE REGION IS IN THE RIGHT FRONT QUADRANT OF AN 80+ KT 250 HPA JET PER 12Z RAOBS. SO WHILE HAVE THE CAPE...NOT THE MUCH THE WAY IN FORCING TO PLAY WITH...OUTSIDE OF RESIDUAL BOUNDARIES FROM YESTERDAY/S CONVECTION AND LINGERING TROUGH OVER THE LOWER HUDSON VALLEY/NE NJ. LATEST HRRR AND RUC PAINT A PICTURE OF ISOLD- SCT CONVECTION FOR REMAINDER OF THE DAY. HAVE LOWERED POPS SLIGHTLY LATE THIS AFTERNOON OVER ZONES TO BELOW 55 PERCENT TO ACCOMMODATE THIS. FOR NOW TEMPERATURE FORECAST FOR SLIGHTLY ABOVE NORMAL HIGHS APPEARS ON TRACK. THERE IS A HIGH RISK OF RIP CURRENTS AT ALL ATLANTIC OCEAN BEACHES THROUGH THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... CONVECTION SHOULD DIE DOWN DURING THE EVENING AS IT MOVES EAST ACROSS LONG ISLAND AND SOUTHERN CT...BUT THEN ANOTHER ROUND OF SHOWERS AND POSSIBLE TSTMS IS LIKELY LATE TONIGHT INTO SAT MORNING...ESPECIALLY EAST ACROSS LONG ISLAND AND SOUTHERN CT...AS A WEAK MID LEVEL IMPULSE MOVES UP THE COAST. LAST TWO RUNS OF THE ECMWF HAVE BEEN MOST AGGRESSIVE WITH THIS FEATURE...HAVE ACCEPTED THIS IDEA BUT TEMPERED WITH THE WEAKER GFS SOLUTION. TEMPERATURES SHOULD CONTINUE TO RUN SLIGHTLY ABOVE SEASONAL NORMS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THE UNSETTLED WEATHER PATTERN CONTINUES THIS WEEKEND INTO THE BEGINNING OF NEXT WEEK WITH THE ONGOING THREAT FOR SHOWERS AND THUNDERSTORMS AS THE REGION SITS BETWEEN A STRONG BERMUDA HIGH/UPPER LEVEL RIDGE TO THE EAST AND A DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION. THIS SYNOPTIC SET UP PROVIDES A CONTINUAL SOUTHERLY FLOW...USHERING IN WARM...VERY MOIST AIR. THE LATEST 00Z MODEL RUNS HAVE GENERALLY GOOD AGREEMENT ON THE PLACEMENT OF THESE FEATURES...WITH ONLY SLIGHT DIVERGENCE TOWARDS THE END OF THE FORECAST PERIOD. SURFACE LOW HOVERS OVER SOUTHEASTERN CANADA SAT NIGHT...WITH A STATIONARY FRONT POSITIONED THROUGH THE TRI STATE AREA. 00Z MODELS HINT OF A BRIEF PERIOD OF DRYING OUT...WITH PW VALUES ONLY AROUND 1.2/1.3 INCHES FOR SAT NIGHT. MADE MENTION OF CHANCE OF SHOWERS/THUNDERSTORMS SAT NIGHT AS A SHORTWAVE PIVOTS AROUND THE EASTERN SIDE OF THE UPPER LEVEL TROUGH. BEST COMBO OF INSTABILITY/SHEAR LOOKS TO BE FARTHER INLAND NORTH AND WEST OF THE CITY...BUT A STRONGER TSTM IS POSSIBLE WITH INSTABILITY VALUES BETWEEN 1000-1500 J/KG AND 0-6KM SHEAR BETWEEN 30 AND 35 KTS. AS THE NEXT SURFACE LOW TRACKS ALONG THE FRONT TO THE NORTHEAST SUNDAY...PW VALUES INCREASE GREATLY OVER THE AREA...WITH VALUES AROUND 2.0 INCHES EXPECTED BY THE AFTERNOON ALONG THE CONTINUAL SOUTHERLY FLOW. SHEAR AND INSTABILITY VALUES REMAIN MARGINAL...WITH THE THINKING THAT HEAVY RAIN WILL BE THE MAIN THREAT WITH ANY SHOWERS AND THUNDERSTORMS THAT FORM SUNDAY. SHOWERS AND THUNDERSTORMS REMAIN LIKELY IN THE FORECAST FOR THE FIRST PART OF THE WEEK WITH THE STATIONARY FRONT HUGGING THE NORTHEAST AND MULTIPLE SHORTWAVES SQUEEZING BETWEEN THE UPPER LEVEL TROUGH TO THE WEST AND THE RIDGE TO THE EAST. BY TUESDAY...THE BERMUDA HIGH/UPPER LEVEL RIDGE NUDGES INTO THE NORTHEAST...DIMINISHING THE THREAT FOR WIDESPREAD PRECIPITATION. THE THREAT FOR THUNDERSTORMS BECOMES MORE DIURNAL AT THIS POINT WITH THE PASSING SHORTWAVES COMBINED WITH DAY TIME HEATING BECOMING THE MAIN TRIGGER RATHER THAN THE FRONTAL BOUNDARY. HAVE INCLUDED CHANCE POPS TO ACCOUNT FOR THIS THROUGH THE END OF THE WEEK...WITH SOME DRYING FINALLY EXPECTED BY FRIDAY AS THE RIDGE AND SURFACE HIGH TAKE MORE CONTROL OF THE NORTHEAST AS THE UPPER LEVEL TROUGH FINALLY WEAKENS AND PROGRESSES EAST. TEMPS NEAR NORMAL FOR THE PERIOD...WITH HIGHS GENERALLY IN THE 80S AND LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... LOW PRESSURE CURRENTLY MOVING AWAY FROM THE REGION TO THE NORTH. A FRONTAL BOUNDARY STALLS OVER THE AREA TODAY. BRIEF SHRA POSSIBLE ACROSS CITY AND INTERIOR TERMINALS LATE THIS MORNING. MINIMAL IMPACT TO OPERATIONS EXPECTED. SCT SHRA AND TSTMS POSSIBLE LATER WITH BETTER OVERALL CHANCES IN THE LATE AFTERNOON INTO EVENING AND HAVE SHOWN THAT VIA TEMPO GROUP EVERYWHERE EXCEPT ISP/GON. GENERALLY VFR...EXCEPT FOR EASTERN TERMINALS...WHICH MAY SEE MVFR CIGS THROUGHOUT THE DAY. MODERATE CONFIDENCE IN GUSTS DEVELOPING BY 16-17Z. 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) KEWR FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. OCCASIONAL MVFR CEILINGS POSSIBLE THROUGH 19-20Z. KLGA FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. OCCASIONAL MVFR CEILINGS POSSIBLE THROUGH 18Z. KTEB FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KHPN FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KISP FCSTER COMMENTS: OCCASIONAL MVFR CEILINGS POSSIBLE THROUGH 18Z. .OUTLOOK FOR 15Z SAT THROUGH TUESDAY... .SAT-TUE...SUB VFR POSSIBLE AT TIMES WITH PERIODS OF SHOWERS AND TSTMS. && .MARINE... SCA REMAINS UP ON THE OCEAN WATERS INTO SATURDAY WITH SEAS AROUND 5 FT...AND POSSIBLE GUSTS UP TO 25 KTS. SCA CONDITIONS EXPECTED ON THE OCEAN WATERS THROUGH THE WEEKEND WITH SEAS BETWEEN 7 AND 9 FT. WIND GUSTS MAY TOUCH 25 KTS AS WELL DURING THIS TIME. SEAS REMAIN ELEVATED DURING THE COMING WEEK WITH A PERSISTENT SOUTHERLY FLOW CONTINUALLY BUILDING UP THE SEAS. WINDS HOWEVER EXPECTED TO REMAIN BELOW SCA CRITERIA...SO ALL WATERS OTHER THAN THE OCEAN SHOULD REMAIN SUB SCA. WILL CONTINUE TO UNDERCUT WAVE WATCH III SEAS BY A FOOT OR SO. && .HYDROLOGY... CONFIDENCE IN FLASH FLOOD WATCH IS DECREASING. IF CURRENT CONVECTIVE TRENDS HOLD...COULD CANCEL EARLY THIS AFTERNOON. WITH SOME UNCERTAINTY ON THE EVOLUTION OF CONVECTION LATER TODAY...HAVE EXTENDED FLASH FLOOD WATCH INTO THIS EVENING FROM NYC METRO NORTH/WEST AND FOR SOUTHWEST CT. CANCELED WATCH FOR EASTERN LONG ISLAND AND SW CT WHERE INSTABILITY AND POTENTIAL FOR HEAVY RAIN WILL BE MITIGATED BY A MORE STABLE ONSHORE FLOW. SHOWERS AND THUNDERSTORMS SUNDAY INTO MONDAY MAY PRODUCE HEAVY RAINFALL...WITH LOCALIZED FLOODING...ESPECIALLY OVER URBAN AND POOR DRAINAGE AREAS. STILL TOO EARLY AT THIS TIME TO DETERMINE RAINFALL TOTALS. FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR CTZ005-006- 009-010. NY...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR NYZ067>075- 176>179. NJ...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR NJZ002-004- 006-103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...MALOIT/GOODMAN/SEARS NEAR TERM...MALOIT/GOODMAN SHORT TERM...GOODMAN LONG TERM...SEARS AVIATION...BC/DH MARINE...MALOIT/GOODMAN/SEARS HYDROLOGY...MALOIT/GOODMAN/SEARS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
919 AM EDT FRI JUN 28 2013 .SYNOPSIS... WARM AND MUGGY CONDITIONS WILL CONTINUE WITH HIT AND MISS SHOWERS AND THUNDERSTORMS INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... *** FLASH FLOOD WATCH IS IN EFFECT THROUGH THIS AFTERNOON. *** 9 AM UPDATE...MOST OF THE SHOWERS ARE MOVING OFF THE EAST COAST OF MASSACHUSETTS AT THIS TIME. THERE REMAIN SHOWERS STRETCHED FROM CAPE ANN TO THE MIDDLE OF CAPE COD. THESE SHOWERS WILL CONTINUE TO MOVE EASTWARD THIS MORNING. THERE IS ALSO A THIN LINE OF SHOWERS STRETCHED THROUGH THE CONNECTICUT VALLEY RIGHT NOW THAT WILL SLOWLY MAKE ITS WAY EAST. APPEARS THAT THE WARM FRONT RUNS FROM JUST NORTH OF ALBANY SOUTHEAST TO JUST SOUTH OF WORCESTER BACK TO THE NORTHEAST TO ABOUT LAWRENCE. EXPECT THIS FRONT TO CONTINUE TO MOVE NORTHWARD AS LOW PRESSURE IN EASTERN NEW YORK STRENGTHENS. WIND GUSTS MAY INCREASE ACROSS THE WEST AS PRESSURE GRADIENT TIGHTENS...UP TO 25 KTS. ON THE CAPE AND ISLANDS...WINDS WILL BE AIDED BY A LOW LEVEL JET. MANY LOCATIONS IN THIS REGION ARE ALREADY GUSTING TO 25 KTS. .PREVIOUS DISCUSSION... MODELS ARE SHOWING SOME DRYING IN THE MID-LEVELS BY LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS. MAIN QUESTION IS THE POTENTIAL FOR STRONG THUNDERSTORMS LATER TODAY. MODELS ARE INDICATING THAT CLOUD COVER WILL BREAK LATER ALLOWING FOR SOME DIURNAL HEATING AND EVENTUALLY SOME THUNDERSTORMS. THE HI-RES WRF AS WELL AS THE HRRR AND OTHER MESOSCALE MODELS ARE ALSO INDICATING THIS FEATURE. IF THIS DOES PLAY OUT BELIEVE THE REGION THAT HAS THE BEST POTENTIAL WILL BE ACROSS THE WORCESTER HILLS AND WEST. THIS REGION SHOWS THE BETTER INSTABILITY...UP TO 2000 J/KG COMBINED WITH BULK SHEAR VALUES AROUND 30KTS AND LAPSE RATES OF 6 C/KM. ALSO HAVE UPPER LEVEL SUPPORT AS THE EXIT REGION OF THE JET MOVES OVER SOUTHERN NEW ENGLAND. IF THUNDERSTORMS DO DEVELOP BELIEVE THAT GUSTY WINDS...HAIL AND HEAVY DOWNPOURS WILL BE THE MAIN THREATS. TEMPERATURES WILL BE TRICKY AGAIN TODAY. WARM FRONT WILL LIFT NORTHWARD ALLOWING FOR WARM AND MOIST AIR INTO THE REGION. HOWEVER FOG AND CLOUDS WILL LIMIT TRUE DIABATIC HEATING. RIGHT NOW EXPECT TEMPS TO BE IN THE MID TO UPPER 70S. IF THE SUN DOES PEAK OUT THEN TEMPS MAY WARM INTO THE LOW 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... ANY ONGOING CONVECTION SHOULD DWINDLE DOWN DURING THE EVENING HOURS AS DIURNAL HEATING IS LOST. STILL LEFT SCATTERED SHOWERS IN THE FORECAST. OTHERWISE MAIN CONCERN WILL BE FOG FOR THE OVERNIGHT HOURS AS VERY HUMID AIRMASS IS STILL IN PLACE. MODELS ARE INDICATING ANOTHER SURGE OF PRECIP TO PUSH ACROSS THE CAPE AND ISLANDS AFTER MIDNIGHT FROM THE LLJ. && .LONG TERM /SATURDAY THROUGH THURSDAY/... OVERVIEW...NOT MUCH CHANGE IN THE OVERALL SYNOPTIC PATTERN WITH THE 28/00Z GUIDANCE. STILL DO NOT HAVE MUCH CONFIDENCE IN THE MESOSCALE DETAILS EVIDENT IN ANY PARTICULAR MODEL. WITH ABOVE AVERAGE AGREEMENT WITH RESPECT TO THE OVERALL SYNOPTIC EVOLUTION...DECIDED TO USE A CONSENSUS BLEND TO TREND THE EXISTING FORECAST. THIS SOLUTION WILL FEATURE STRONG RIDGES DEVELOPING OVER THE WESTERN USA AS WELL AS THE WESTERN ATLANTIC. A SHORTWAVE MOVING OVER THE GREAT LAKES INTO THE MISSISSIPPI VALLEY AND FORMS AN ANOMALOUSLY STRONG CUTOFF LOW OVER THAT AREA. THIS UPPER LOW EVENTUALLY EJECTS INTO THE /CANADIAN/ WESTERLIES DURING THE MIDDLE OF NEXT WEEK. THE DAILIES... SATURDAY... ANOTHER SHORTWAVE ROTATES AROUND A GREAT LAKES UPPER LOW AND CROSSES EASTERN NY/NEW ENGLAND. A SUPPORTING UPPER JET HAS ITS RIGHT ENTRANCE REGION OVER NEW ENGLAND. A COLD FRONT STALLS OVER OR NEAR THE REGION AND PROVIDES A FOCUS FOR LOW LEVEL CONVERGENCE. PLENTY OF MOISTURE AVAILABLE WITH PRECIPITABLE WATER VALUES BETWEEN 1.5 AND 2.0 INCHES...HIGHEST SOUTHEAST. WE WILL FEATURE HIGHER POPS. WE WILL ALSO MENTION LOCALLY HEAVY DOWNPOURS DUE TO THE HIGH MOISTURE CONTENT. SUNDAY THROUGH THURSDAY...NOT MUCH CHANGE IN THE UPPER PATTERN WITH CLOSED LOW TO THE WEST AND UPPER RIDGE TO THE EAST...AND A MOIST SOUTH FLOW CONTINUING TO SUPPLY HIGH MOISTURE CONTENT AIR. WE WILL CONTINUE TO FEATURE AT LEAST A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TODAY...MODERATE CONFIDENCE. IFR/LIFR CONDITIONS EARLY... IMPROVING TO MVFR/IFR EAST AND MVFR/PATCHY VFR WEST. OVERALL IMPROVEMENTS BY LATE MORNING WEST TO EAST. HOWEVER SHOWERS AND THUNDERSTORMS WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON HOURS. THEREFORE MVFR OUT WEST IN ANY HEAVY THUNDERSTORM. TONIGHT...VFR/MVFR WILL SLOWLY DROP TO MVFR/IFR ACROSS THE REGION IS LOW CLOUDS AND FOG. BEST REGION FOR LOWEST CONDITIONS WILL BE ALONG THE SOUTH COAST. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. CONFIDENT IN OVERALL TRENDS HOWEVER LOW CONFIDENCE IN TIMING...PARTICULARLY WITH CONVECTION. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. CONFIDENT IN OVERALL TRENDS HOWEVER LOW CONFIDENCE IN TIMING...PARTICULARLY WITH CONVECTION. OUTLOOK...SATURDAY THROUGH TUESDAY... MODERATE CONFIDENCE. PLENTY OF SHOWERS/TSTMS THIS WEEKEND WITH PERIODS OF MVFR CIGS/VSBYS IN SHOWERS...SOME OF THEM QUITE HEAVY. THE VERY HUMID AIRMASS WILL ALSO PRODUCE AREAS OF FOG AT NIGHT AND EARLY MORNING WITH IFR CIGS/VSBYS IN ANY SUCH FOG. POTENTIAL FOR VSBYS NEAR 1/4 MILE AT TIMES. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH FRIDAY...HIGH CONFIDENCE. SHORT-TERM THROUGH FRIDAY NIGHT...HIGH CONFIDENCE. SCA STILL CONTINUES ACROSS THE WATERS. CONTINUED TO UNDERCUT WNA WAVE GUIDANCE BY ABOUT 10 PERCENT TO ACCOUNT FOR ITS SOUTHERLY BIAS. OTHERWISE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO IMPACT THE WATERS TODAY AND INTO TONIGHT. MAIN THREATS WILL BE LIGHTNING AND HEAVY DOWNPOURS IMPACTING VISIBILITIES. OUTLOOK...SATURDAY THROUGH TUESDAY... PERIODS OF SHOWERS/TSTMS/FOG EXPECTED WITH VERY HUMID AIR CONTINUING. THERE WILL BE POOR VSBYS AT TIMES...AND 1/4 MILE VSBYS IN FOG POSSIBLE EARLY EACH MORNING. SOUTH TO SOUTHWEST WINDS THROUGH THE PERIOD. WIND GUSTS MAY APPROACH 25 KNOTS AT TIMES SATURDAY...BUT BE PRIMARILY 20 KNOTS OR LESS. THE STEADY WIND DIRECTION WILL HELP BUILD SEAS WITH WAVE HEIGHTS OF 5 TO 10 FEET EXPECTED ACROSS THE OUTER COASTAL WATERS AND EXPOSED PORTIONS OF THE SOUTHERN SOUNDS SUCH AS RI SOUND AND POSSIBLY BLOCK ISLAND SOUND. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THESE ROUGH SEAS THROUGH MIDWEEK...ESPECIALLY ACROSS THE OUTER COASTAL WATERS. && .HYDROLOGY... FLASH FLOOD WATCH CONTINUES THROUGH TODAY. RADAR ESTIMATED RAINFALL RATES UP TO 6 IN PER HOUR WITHIN SOME OF THE STRONGER THUNDERSTORMS LAST NIGHT. FORTUNATELY THESE THUNDERSTORMS REMAINED PROGRESSIVE AND DID NOT LINGER OVER ANY ONE LOCATION FOR VERY LONG. THESE RAINFALL RATES DO INDICATE THE POTENTIAL FOR HEAVY RAINFALL WITHIN THIS SOUPY AIRMASS. WILL NEED TO ESPECIALLY WATCH REGIONS OF HIGHER TERRAIN WHERE UPSLOPE COULD ENHANCE THE RAINFALL AS WELL AS URBANIZED AREAS... WHERE CONVECTIVE HEAVY RAIN MAY LEAD TO URBAN FLASH FLOODING. && .CLIMATE... WITH THE POTENTIAL FOR HEAVY RAIN TONIGHT INTO FRIDAY WE WILL BE ADDING TO THE ALREADY HIGH MONTHLY TOTALS FOR RAIN. BELOW PLEASE FIND THE TOP 10 WETTEST JUNE RAINFALL TOTALS FOR EACH OF OUR FOUR CLIMATE SITES...THESE INCLUDE RAINFALL TOTALS FOR JUNE 2013 ENDING AT 1 AM THE MORNING OF JUNE 28. BOSTON... 1. 13.20 INCHES IN 1982 2. 11.58 INCHES IN 1998 3. 10.09 INCHES IN 2006 4. 9.87 INCHES IN 2013 5. 9.13 INCHES IN 1931 6. 8.63 INCHES IN 1959 7. 8.05 INCHES IN 1922 8. 7.79 INCHES IN 1881 9. 7.74 INCHES IN 1986 10. 7.25 INCHES IN 1875 HARTFORD... 1. 13.60 INCHES IN 1982 2. 10.62 INCHES IN 2013 3. 9.66 INCHES IN 1972 4. 9.16 INCHES IN 2006 5. 8.08 INCHES IN 1937 6. 8.00 INCHES IN 1920 7. 7.79 INCHES IN 1948 8. 7.18 INCHES IN 1998 9. 6.92 INCHES IN 1922 10. 6.79 INCHES IN 1986 PROVIDENCE... 1. 11.08 INCHES IN 1982 2. 9.61 INCHES IN 1998 3. 9.39 INCHES IN 2013 4. 9.24 INCHES IN 2006 5. 7.21 INCHES IN 1938 6. 6.83 INCHES IN 1978 7. 6.80 INCHES IN 1920 8. 6.72 INCHES IN 2001 9. 6.58 INCHES IN 1922 10. 5.84 INCHES IN 1989 WORCESTER... 1. 12.17 INCHES IN 1982 2. 9.68 INCHES IN 1998 3. 9.55 INCHES IN 2013 4. 9.25 INCHES IN 1972 5. 8.31 INCHES IN 1922 6. 7.78 INCHES IN 1968 7. 7.44 INCHES IN 1903 8. 7.39 INCHES IN 1938 9. 7.21 INCHES IN 1986 10. 6.98 INCHES IN 1973 & 1935 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR CTZ002>004. MA...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR MAZ002>021- 026. NH...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR NHZ011-012- 015. RI...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ235-237- 250-254>256. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...BELK/DUNTEN/RLG SHORT TERM...DUNTEN LONG TERM...BELK AVIATION...BELK/DUNTEN MARINE...BELK/DUNTEN HYDROLOGY...STAFF CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
745 AM EDT FRI JUN 28 2013 .SYNOPSIS... WARM AND MUGGY CONDITIONS WILL CONTINUE WITH HIT AND MISS SHOWERS AND THUNDERSTORMS INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 730 AM UPDATE...OVERALL FORECAST TREND REMAINS ON TRACK. HAVE UPDATED TO ACCOUNT FOR CURRENT SITUATION. APPEARS WARM FRONT IS DRAPED FROM JUST NORTH OF PROVINCETOWN...TO JUST SOUTH OF WORCESTER...THEN NORTHWEST INTO SOUTHERN VERMONT. EXPECT THIS FRONT TO CONTINUE NORTHWARD AS A LOW PRESSURE STRENGTHENS. WIND GUSTS MAY INCREASE ACROSS THE WEST AS PRESSURE GRADIENT TIGHTENS...UP TO 25 KTS. TODAY... *** FLASH FLOOD WATCH IS IN EFFECT THROUGH THIS AFTERNOON. *** LOW PRESSURE SYSTEM WILL SLIDE NORTHWARD BY FRIDAY. THIS WILL PUSH THE WARM FRONT/BOUNDARY NORTHWARD INTO NH ALLOWING FOR GOOD SOUTHERLY FLOW ACROSS THE REGION. SCATTERED SHOWERS WILL CONTINUE ESP ACROSS THE NORTHWEST PORTION OF THE REGION THIS MORNING. A FEW EMBEDDED THUNDERSTORMS MAY OCCUR AS WELL. OTHERWISE BELIEVE OVERALL AREAL COVERAGE WILL BE DISSIPATING. LOW LEVEL JET WILL STILL BE ANCHORED ACROSS THE CAPE/EASTERN WATERS THROUGH THE DAY WHICH COULD MAKE THINGS A TAD BREEZY ACROSS THE CAPE AND ISLANDS. MODELS ARE SHOWING SOME DRYING IN THE MID-LEVELS BY LATE THIS MORNING INTO THE EARLY AFTERNOON HOURS. MAIN QUESTION IS THE POTENTIAL FOR STRONG THUNDERSTORMS LATER TODAY. MODELS ARE INDICATING THAT CLOUD COVER WILL BREAK LATER ALLOWING FOR SOME DIURNAL HEATING AND EVENTUALLY SOME THUNDERSTORMS. THE HI-RES WRF AS WELL AS THE HRRR AND OTHER MESOSCALE MODELS ARE ALSO INDICATING THIS FEATURE. IF THIS DOES PLAY OUT BELIEVE THE REGION THAT HAS THE BEST POTENTIAL WILL BE ACROSS THE WORCESTER HILLS AND WEST. THIS REGION SHOWS THE BETTER INSTABILITY...UP TO 2000 J/KG COMBINED WITH BULK SHEAR VALUES AROUND 30KTS AND LAPSE RATES OF 6 C/KM. ALSO HAVE UPPER LEVEL SUPPORT AS THE EXIT REGION OF THE JET MOVES OVER SOUTHERN NEW ENGLAND. IF THUNDERSTORMS DO DEVELOP BELIEVE THAT GUSTY WINDS...HAIL AND HEAVY DOWNPOURS WILL BE THE MAIN THREATS. SPC HAS OUTLOOKED MOST OF THE REGION WITHIN THEIR DAY 1 OUTLOOK. WE HAVE ALSO BEEN PLACED IN A 2 PERCENT TORNADO PROBABILITY. BELIEVE THE POTENTIAL IS LOW ESP SINCE SURFACE WINDS WILL BE MORE OUT OF THE SOUTH RATHER THAN THE WSW ALTHOUGH IT IS SOMETHING FOR THE DAY SHIFT TO EVALUATE. TEMPERATURES WILL BE TRICKY AGAIN TODAY. WARM FRONT WILL LIFT NORTHWARD ALLOWING FOR WARM AND MOIST AIR INTO THE REGION. HOWEVER FOG AND CLOUDS WILL LIMIT TRUE DIABATIC HEATING. RIGHT NOW EXPECT TEMPS TO BE IN THE MID TO UPPER 70S. IF THE SUN DOES PEAK OUT THEN TEMPS MAY WARM INTO THE LOW 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... ANY ONGOING CONVECTION SHOULD DWINDLE DOWN DURING THE EVENING HOURS AS DIURNAL HEATING IS LOST. STILL LEFT SCATTERED SHOWERS IN THE FORECAST. OTHERWISE MAIN CONCERN WILL BE FOG FOR THE OVERNIGHT HOURS AS VERY HUMID AIRMASS IS STILL IN PLACE. MODELS ARE INDICATING ANOTHER SURGE OF PRECIP TO PUSH ACROSS THE CAPE AND ISLANDS AFTER MIDNIGHT FROM THE LLJ. && .LONG TERM /SATURDAY THROUGH THURSDAY/... OVERVIEW...NOT MUCH CHANGE IN THE OVERALL SYNOPTIC PATTERN WITH THE 28/00Z GUIDANCE. STILL DO NOT HAVE MUCH CONFIDENCE IN THE MESOSCALE DETAILS EVIDENT IN ANY PARTICULAR MODEL. WITH ABOVE AVERAGE AGREEMENT WITH RESPECT TO THE OVERALL SYNOPTIC EVOLUTION...DECIDED TO USE A CONSENSUS BLEND TO TREND THE EXISTING FORECAST. THIS SOLUTION WILL FEATURE STRONG RIDGES DEVELOPING OVER THE WESTERN USA AS WELL AS THE WESTERN ATLANTIC. A SHORTWAVE MOVING OVER THE GREAT LAKES INTO THE MISSISSIPPI VALLEY AND FORMS AN ANOMALOUSLY STRONG CUTOFF LOW OVER THAT AREA. THIS UPPER LOW EVENTUALLY EJECTS INTO THE /CANADIAN/ WESTERLIES DURING THE MIDDLE OF NEXT WEEK. THE DAILIES... SATURDAY... ANOTHER SHORTWAVE ROTATES AROUND A GREAT LAKES UPPER LOW AND CROSSES EASTERN NY/NEW ENGLAND. A SUPPORTING UPPER JET HAS ITS RIGHT ENTRANCE REGION OVER NEW ENGLAND. A COLD FRONT STALLS OVER OR NEAR THE REGION AND PROVIDES A FOCUS FOR LOW LEVEL CONVERGENCE. PLENTY OF MOISTURE AVAILABLE WITH PRECIPITABLE WATER VALUES BETWEEN 1.5 AND 2.0 INCHES...HIGHEST SOUTHEAST. WE WILL FEATURE HIGHER POPS. WE WILL ALSO MENTION LOCALLY HEAVY DOWNPOURS DUE TO THE HIGH MOISTURE CONTENT. SUNDAY THROUGH THURSDAY...NOT MUCH CHANGE IN THE UPPER PATTERN WITH CLOSED LOW TO THE WEST AND UPPER RIDGE TO THE EAST...AND A MOIST SOUTH FLOW CONTINUING TO SUPPLY HIGH MOISTURE CONTENT AIR. WE WILL CONTINUE TO FEATURE AT LEAST A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TODAY...MODERATE CONFIDENCE. IFR/LIFR CONDITIONS EARLY... IMPROVING TO MVFR/IFR EAST AND MVFR/PATCHY VFR WEST. OVERALL IMPROVEMENTS BY LATE MORNING WEST TO EAST. HOWEVER SHOWERS AND THUNDERSTORMS WILL REDEVELOP DURING THE LATE MORNING AND AFTERNOON HOURS. THEREFORE MVFR OUT WEST IN ANY HEAVY THUNDERSTORM. TONIGHT...VFR/MVFR WILL SLOWLY DROP TO MVFR/IFR ACROSS THE REGION IS LOW CLOUDS AND FOG. BEST REGION FOR LOWEST CONDITIONS WILL BE ALONG THE SOUTH COAST. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. CONFIDENT IN OVERALL TRENDS HOWEVER LOW CONFIDENCE IN TIMING...PARTICULARLY WITH CONVECTION. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. CONFIDENT IN OVERALL TRENDS HOWEVER LOW CONFIDENCE IN TIMING...PARTICULARLY WITH CONVECTION. OUTLOOK...SATURDAY THROUGH TUESDAY... MODERATE CONFIDENCE. PLENTY OF SHOWERS/TSTMS THIS WEEKEND WITH PERIODS OF MVFR CIGS/VSBYS IN SHOWERS...SOME OF THEM QUITE HEAVY. THE VERY HUMID AIRMASS WILL ALSO PRODUCE AREAS OF FOG AT NIGHT AND EARLY MORNING WITH IFR CIGS/VSBYS IN ANY SUCH FOG. POTENTIAL FOR VSBYS NEAR 1/4 MILE AT TIMES. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT-TERM THROUGH FRIDAY...HIGH CONFIDENCE. SHORT-TERM THROUGH FRIDAY NIGHT...HIGH CONFIDENCE. SCA STILL CONTINUES ACROSS THE WATERS. CONTINUED TO UNDERCUT WNA WAVE GUIDANCE BY ABOUT 10 PERCENT TO ACCOUNT FOR ITS SOUTHERLY BIAS. OTHERWISE SHOWERS AND THUNDERSTORMS WILL CONTINUE TO IMPACT THE WATERS TODAY AND INTO TONIGHT. MAIN THREATS WILL BE LIGHTNING AND HEAVY DOWNPOURS IMPACTING VISIBILITIES. OUTLOOK...SATURDAY THROUGH TUESDAY... PERIODS OF SHOWERS/TSTMS/FOG EXPECTED WITH VERY HUMID AIR CONTINUING. THERE WILL BE POOR VSBYS AT TIMES...AND 1/4 MILE VSBYS IN FOG POSSIBLE EARLY EACH MORNING. SOUTH TO SOUTHWEST WINDS THROUGH THE PERIOD. WIND GUSTS MAY APPROACH 25 KNOTS AT TIMES SATURDAY...BUT BE PRIMARILY 20 KNOTS OR LESS. THE STEADY WIND DIRECTION WILL HELP BUILD SEAS WITH WAVE HEIGHTS OF 5 TO 10 FEET EXPECTED ACROSS THE OUTER COASTAL WATERS AND EXPOSED PORTIONS OF THE SOUTHERN SOUNDS SUCH AS RI SOUND AND POSSIBLY BLOCK ISLAND SOUND. A SMALL CRAFT ADVISORY WILL BE NEEDED FOR THESE ROUGH SEAS THROUGH MIDWEEK...ESPECIALLY ACROSS THE OUTER COASTAL WATERS. && .HYDROLOGY... FLASH FLOOD WATCH CONTINUES THROUGH TODAY. RADAR ESTIMATED RAINFALL RATES UP TO 6 IN PER HOUR WITHIN SOME OF THE STRONGER THUNDERSTORMS LAST NIGHT. FORTUNATELY THESE THUNDERSTORMS REMAINED PROGRESSIVE AND DID NOT LINGER OVER ANY ONE LOCATION FOR VERY LONG. THESE RAINFALL RATES DO INDICATE THE POTENTIAL FOR HEAVY RAINFALL WITHIN THIS SOUPY AIRMASS. WILL NEED TO ESPECIALLY WATCH REGIONS OF HIGHER TERRAIN WHERE UPSLOPE COULD ENHANCE THE RAINFALL AS WELL AS URBANIZED AREAS... WHERE CONVECTIVE HEAVY RAIN MAY LEAD TO URBAN FLASH FLOODING. && .CLIMATE... WITH THE POTENTIAL FOR HEAVY RAIN TONIGHT INTO FRIDAY WE WILL BE ADDING TO THE ALREADY HIGH MONTHLY TOTALS FOR RAIN. BELOW PLEASE FIND THE TOP 10 WETTEST JUNE RAINFALL TOTALS FOR EACH OF OUR FOUR CLIMATE SITES...THESE INCLUDE RAINFALL TOTALS FOR JUNE 2013 ENDING AT MIDNIGHT THE MORNING OF JUNE 27. BOSTON... 1. 13.20 INCHES IN 1982 2. 11.58 INCHES IN 1998 3. 10.09 INCHES IN 2006 4. 9.87 INCHES IN 2013 5. 9.13 INCHES IN 1931 6. 8.63 INCHES IN 1959 7. 8.05 INCHES IN 1922 8. 7.79 INCHES IN 1881 9. 7.74 INCHES IN 1986 10. 7.25 INCHES IN 1875 HARTFORD... 1. 13.60 INCHES IN 1982 2. 10.62 INCHES IN 2013 3. 9.66 INCHES IN 1972 4. 9.16 INCHES IN 2006 5. 8.08 INCHES IN 1937 6. 8.00 INCHES IN 1920 7. 7.79 INCHES IN 1948 8. 7.18 INCHES IN 1998 9. 6.92 INCHES IN 1922 10. 6.79 INCHES IN 1986 PROVIDENCE... 1. 11.08 INCHES IN 1982 2. 9.61 INCHES IN 1998 3. 9.39 INCHES IN 2013 4. 9.24 INCHES IN 2006 5. 7.21 INCHES IN 1938 6. 6.83 INCHES IN 1978 7. 6.80 INCHES IN 1920 8. 6.72 INCHES IN 2001 9. 6.58 INCHES IN 1922 10. 5.84 INCHES IN 1989 WORCESTER... 1. 12.17 INCHES IN 1982 2. 9.68 INCHES IN 1998 3. 9.55 INCHES IN 2013 4. 9.25 INCHES IN 1972 5. 8.31 INCHES IN 1922 6. 7.78 INCHES IN 1968 7. 7.44 INCHES IN 1903 8. 7.39 INCHES IN 1938 9. 7.21 INCHES IN 1986 10. 6.98 INCHES IN 1973 & 1935 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR CTZ002>004. MA...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR MAZ002>021- 026. NH...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR NHZ011-012- 015. RI...FLASH FLOOD WATCH UNTIL 6 PM EDT THIS EVENING FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ235-237- 254>256. SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ250. && $$ SYNOPSIS...DUNTEN/BELK NEAR TERM...BELK/DUNTEN SHORT TERM...DUNTEN LONG TERM...BELK AVIATION...DUNTEN/BELK MARINE...DUNTEN/BELK HYDROLOGY...STAFF CLIMATE...STAFF
AREA FORECAST DISCUSSION
NWS MIAMI FL
1041 AM EDT FRI JUN 28 2013 .UPDATE... CHANGES ARE NOT BEING PLANNED AT THIS TIME FOR THE MORNING UPDATES. THE 12Z MFL SOUNDING SHOWS THE WIND FIELD REMAINS VERY WEAK BUT MODELS SHOW THIS PATTERN CHANGING THROUGHOUT THE DAY WITH A SLIGHTLY MORE SW-NE STEERING FLOW DEVELOPING BY THIS AFTERNOON. THE TROUGH DEEPENING OVER THE EASTERN U.S. HAS DEVELOPED A MORE WESTERLY FLOW ACROSS SOUTH FLORIDA ABOVE 20K FEET AND THIS REFLECTED IN THE POP AND WEATHER GRIDS BY SHOWING THE GREATEST CHANCE OF CONVECTION OVER THE INTERIOR AND NORTHEAST PORTION OF THE REGION. THE HRRR SHOWS SEA BREEZE DEVELOPMENT TYPE SHOWERS NEAR BOTH COASTS AND THEN SPORADIC MOVEMENT INTO THIS AFTERNOON BUT WITH A SLOW MIGRATION TOWARDS THE NORTHEAST. BASED ON LATER CONDITIONS, THE MAIN AFTERNOON FORECAST MAY NEED TO BE CHANGED SLIGHTLY FOR THE TRENDS AT THAT TIME. KOB && .PREV DISCUSSION... /ISSUED 807 AM EDT FRI JUN 28 2013/ AVIATION... SOUTHERLY LOW LEVEL FLOW IS EXPECTED TODAY...WITH WESTERLY FLOW ALOFT. SHOWERS AND THUNDERSTORMS ARE FORECAST TO START MAINLY OVER THE INTERIOR ALONG THE SEA BREEZE BOUNDARIES. INCLUDED VCTS FOR ALL TERMINALS AFTER 17Z. FOR APF INCLUDED VCTS THIS MORNING SINCE THE FLOW IS SHOWING SIGNS OF BRINGING MOISTURE FROM THE GULF INTO THE WEST COAST AS WINDS SHIFT MORE TO THE SOUTH AFTER SUNRISE. A FEW SHOWERS ARE ALSO PRESENT THIS MORNING OVER THE ATLANTIC WATERS BUT THEY ARE HAVING MORE DIFFICULTY PENETRATING INLAND AS THE FLOW SHIFTS TO THE SOUTH. HOWEVER, INCLUDED VCSH FOR TMB UNTIL 17Z SINCE SHOWERS CAN SPREAD INTO THE AREA FROM THE SOUTH. PREV DISCUSSION... /ISSUED 246 AM EDT FRI JUN 28 2013/ DISCUSSION... AN UPPER LEVEL TROUGH ACROSS THE EASTERN SEA BOARD WILL GET REINFORCED AND DEEPEN INTO THE SOUTHEAST THIS WEEKEND INTO EARLY NEXT WEEK AS AREAS OF VORTICITY ROTATE AROUND A MEAN CENTER...AND A SERIES OF SHORTWAVES DIVE SOUTH OUT OF CANADA ON THE BACK SIDE OF THE TROUGH. THE SURFACE RIDGE AXIS IS FORECAST TO BE LOCATED ACROSS THE MIDDLE OF THE REGION AROUND 12Z THIS MORNING...AND THEN WEAKEN AND SHIFT SOUTHEAST THROUGH THE WEEKEND. THIS WILL ALLOW DEEP SOUTHWESTERLY FLOW TO DEVELOP ACROSS SOUTH FLORIDA SATURDAY NIGHT INTO SUNDAY. SO THIS MEANS A GENERALLY WETTER PATTERN FOR SOUTH FLORIDA THROUGH EARLY NEXT WEEK. SOUTHERLY LOW LEVEL FLOW IS EXPECTED TODAY...WITH WESTERLY FLOW ALOFT. MODELS ARE INDICATING A BIT LATER START TO THE DIURNALLY DRIVEN CONVECTION...WITH SHOWERS AND THUNDERSTORMS STARTING MAINLY OVER THE INTERIOR ALONG THE SEA BREEZE BOUNDARIES. THE FLOW OFF THE SURFACE IS FORECAST TO VEER MORE TO THE SOUTHWEST AND WEST THROUGHOUT THE DAY...AND STORMS SHOULD DRIFT BACK TO THE EAST COAST IN THE MID/LATE AFTERNOON AND THROUGH THE EVENING HOURS. THE CHANCE OF SHOWERS AND STORMS WILL BE LESS ACROSS THE NAPLES REGION TODAY AS SHOWERS CONCENTRATE ACROSS THE INTERIOR AND MOVE EAST. AN UNUSUALLY STRONG AND DEEP UPPER LEVEL TROUGH WILL CONTINUE TO DIG INTO THE SOUTHEAST THROUGH THE WEEKEND. MODELS ARE INDICATING THAT DRIER LOW LEVEL AIR WILL MOVE INTO THE REGION ON SATURDAY AS WINDS SHIFT TO THE SOUTHWEST. IN ADDITION...THE BEST FORCING WILL BE ACROSS CENTRAL FLORIDA AND EASTWARD INTO THE ATLANTIC ASSOCIATED WITH THE UPPER TROUGH. GFS POPS HAVE THUS COME DOWN AS WELL. ONLY DROPPED POPS SLIGHTLY FOR SATURDAY...WITH THE BEST CHANCE ACROSS THE LAKE REGION AND PALM BEACH COUNTY. DEEPER MOISTURE IS EXPECTED TO BEGIN MOVING FROM THE SOUTH SATURDAY NIGHT...AND NOCTURNAL SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE REGION...ESPECIALLY ACROSS THE SOUTH. AS THE DEEPER MOISTURE CONTINUES ACROSS THE REGION ON SUNDAY...CLOUD COVER WILL INCREASE...BUT NUMEROUS SHOWERS AND THUNDERSTORMS CAN BE EXPECTED AREA WIDE. WITH THE SOUTHWESTERLY FLOW AT ALL LEVELS...ABOVE NORMAL TEMPERATURES ARE NORMALLY THE CASE FOR THE EAST COAST AREAS DUE TO THE ATLANTIC SEA BREEZE BEING HELD OFFSHORE UNTIL THE AFTERNOON. HOWEVER...THE LOWERING HEIGHTS THROUGH THE WEEKEND...INCREASING CLOUD COVER...AND RAINFALL ESPECIALLY ON SUNDAY SHOULD KEEP TEMPERATURES NEAR NORMAL THROUGH THE WEEKEND. THE UPPER LEVEL TROUGH/CUTOFF UPPER LOW WILL BEGIN TO RETROGRADE TO THE WEST IN THE EARLY TO THE MIDDLE PART OF NEXT WEEK...AND THE FLOW WILL BACK TO THE SOUTH AND THEN SOUTHEAST. SO THE BEST RAIN CHANCES FOR THE AFTERNOON HOURS ARE FORECAST TO SHIFT BACK TO TOWARDS THE INTERIOR AND GULF COAST. MARINE... A GENERAL SOUTH WIND WILL CONTINUE TODAY AND THEN VEER TO THE SOUTHWEST OVER THE WEEKEND AT SPEEDS OF 15 KNOTS OR LESS. THUS, SEAS WILL REMAIN WELL BELOW ADVISORY LEVELS BUT THERE COULD BE SOME LOCALLY ROUGH SEAS NEAR STRONGER THUNDERSTORMS MAINLY OVER LAKE OKEECHOBEE AND NEAR BOTH COASTS OF THE PENINSULA. FIRE WEATHER... A WET PATTERN IS IN STORE FOR SOUTH FLORIDA THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. HIGH RELATIVE HUMIDITY VALUES ARE EXPECTED THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 77 88 77 / 60 50 50 30 FORT LAUDERDALE 88 79 89 79 / 60 50 50 40 MIAMI 89 77 90 78 / 50 40 40 40 NAPLES 90 75 89 76 / 30 20 40 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1011 AM CDT FRI JUN 28 2013 .UPDATE... ISSUED AT 1006 AM CDT FRI JUN 28 2013 BASED ON DATA THROUGH 15Z...THERMALS SHOULD BEGIN DEVELOPING WITHIN THE HOUR WITH DIURNAL CU BY MID DAY. AS SUCH THE REMAINDER OF THE MORNING WILL REMAIN DRY ACROSS THE AREA. RAP TRENDS INDICATE THE CONVECTIVE TEMPERATURE WILL SLOWLY DROP DURING THE DAY WHICH WHEN COMBINED WITH THE APPROACHING VORT MAX SHOULD INITIATE CONVECTION DURING THE AFTERNOON. CONVECTION IS EXPECTED TO BE IN THE FORM OF SHOWERS WITH SOME THUNDERSTORMS. CONVECTION WILL CONTINUE INTO THE EVENING WITH THE THUNDERSTORMS DISSIPATING WITH SUNSET. HOWEVER...THE PROXIMITY OF THE COOL POOL ALOFT AND UPPER LOW SHOULD KEEP SHOWERS GOING WELL INTO THE EVENING AND OVERNIGHT HOURS WITH DECREASING COVERAGE. ..08.. && .SYNOPSIS... ISSUED AT 300 AM CDT FRI JUN 28 2013 WATER VAPOR LOOPS SHOWED A BROAD UPPER TROUGH ACROSS THE GREAT LAKES WITH A CLOSED LOW ON THE NORTHERN TIP OF LAKE SUPERIOR. A STRONG SHORT WAVE/VORT MAX WAS LOCATED IN NORTHEAST MN. A FEW SHOWERS WERE NOTED IN CENTRAL WI. OTHERWISE CLEAR SKIES WERE ACROSS THE DVN CWA WHILE A LARGE MCS WAS COVERING SOUTHERN MO AHEAD OF A COLD FRONT. CURRENT TEMPERATURES IN THE DVN CWA RANGED FROM THE MID 60S TO LOWER 70S WITH DEWPOINTS IN THE UPPER 50S NW TO UPPER 60S SE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 300 AM CDT FRI JUN 28 2013 FORECAST FOCUS ON SHOWER CHANCES...CLOUD TRENDS AND TEMPERATURES. TODAY...OPERATIONAL MODELS SLIDE THE GREAT LAKES TROUGH SOUTHWARD INTO OUR REGION WITH THE RAP DEPICTING A STRONG VORT MAX MOVING FROM NORTHEAST MN INTO NORTHERN IL THIS AFTERNOON. WITH COOLING TEMPERATURES ALOFT COMBINED WITH DAYTIME HEATING INSTABILITY WILL INCREASE. HAVE CONFINED POPS TO THIS AFTERNOON AND ALSO ACROSS OUR NORTHEAST HALF CWA CLOSER TO THE TRACK OF THE VORT MAX. THE HRRR MESO MODEL DEPICTS THE POPCORN DESCRIPTION OF THE SCATTERED INSTABILITY SHOWERS (AND A FEW THUNDERSTORMS) QUITE WELL. THERE WILL BE PLENTY OF SUNSHINE FOR MOST OF THIS MORNING BUT CLOUDS WILL DEVELOP/FILL AS THE CONVECTIVE TEMPERATURE IS REACHED. MAXIMUM TEMPERATURES WILL RANGE FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH BUT HUMIDITY LEVELS WILL BE THANKFULLY LOWER COMPARED TO THE LAST FEW DAYS. TONIGHT...WITH THE UPPER TROUGH OVER THE AREA WILL CONTINUE WITH CHANCE POPS AS SKIES WILL BE MOSTLY CLOUDY OR BECOME MOSTLY CLOUDY. HOWEVER...WITH THE LOSS OF HEATING/BETTER INSTABILITY THE COVERAGE OF SHOWERS WILL DECREASE OVERNIGHT. MINIMUM TEMPERATURES SHOULD BE IN THE LOWER 60S AT MOST LOCATIONS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 300 AM CDT FRI JUN 28 2013 A DIGGING UPPER TROF OVER THE EASTERN U.S IS FORECAST TO CLOSE OFF OVER THE OHIO VALLEY BY LATE IN THE WEEKEND. THEN...MODELS ARE IN AGREEMENT THAT THE CLOSED LOW WILL RETROGRADE INTO THE MID MISSISSIPPI VALLEY EARLY IN THE WEEK AND REMAIN THERE...THEN GRADUALLY FILLING DURING THE LATTER HALF OF THE WEEK. THIS PATTERN WILL SUPPORT BELOW NORMAL TEMPERATURES THROUGH THE FORECAST PERIOD WITH HIGHS GENERALLY IN THE 70S TO AROUND 80 AND LOWS...ESPECIALLY EARLY IN THE WEEK...IN THE 50S. MOST DAYS WILL HAVE AT LEAST A LOW THREAT OF RAIN. HOWEVER...AS STATED IN THE PREVIOUS DISCUSSION...THE RAIN THREAT WILL BE LIMITED TO JUST A FEW HOURS EACH DAY. THE BETTER CHANCE OF RAIN DURING THE PERIOD WILL BE SATURDAY AS A SERIES OF S/WS DROP INTO THE DEVELOPING TROF TO OUR EAST. THE BETTER UPPER FORCING APPEARS TO BE JUST EAST OF THE FORECAST AREA...SO KEPT THE HIGHER CHANCE AND LIKELY POPS NEAR AND EAST OF THE MISSISSIPPI RIVER. THE RAIN THREAT WILL DIMINISH SATURDAY NIGHT AND SUNDAY AS DRIER LOW LEVEL AIR FILTERS IN FROM THE NORTH. THE DRY WEATHER SHOULD LAST THROUGH MONDAY THEN A LOW RAIN THREAT RETURNS MONDAY NIGHT THROUGH THE END OF THE WEEK AS THE UPPER LOW BACKS INTO THE REGION FROM THE EAST. THIS WILL SUPPORT MAINLY AFTERNOON ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS. SINCE ANY SHRA/TSRA ACTIVITY WILL PROBABLY BE TIED TO AFTERNOON HEATING...HAVE LIMITED THE POPS TO THE DAYTIME HOURS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 627 AM CDT FRI JUN 28 2013 VFR CONDS TODAY AND TONIGHT. SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP THIS AFTERNOON ACROSS PORTIONS OF EASTERN IA AND NORTHWEST IL. A FEW SHOWERS MAY LINGER INTO TONIGHT. NORTHWEST WINDS INCREASING TO 15 TO 20 KNOTS WITH GUSTS TO 25 KNOTS THIS AFTERNOON. NORTHWEST WINDS AROUND 10 KNOTS TONIGHT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...DLF AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
636 AM CDT FRI JUN 28 2013 .SYNOPSIS... ISSUED AT 300 AM CDT FRI JUN 28 2013 WATER VAPOR LOOPS SHOWED A BROAD UPPER TROUGH ACROSS THE GREAT LAKES WITH A CLOSED LOW ON THE NORTHERN TIP OF LAKE SUPERIOR. A STRONG SHORT WAVE/VORT MAX WAS LOCATED IN NORTHEAST MN. A FEW SHOWERS WERE NOTED IN CENTRAL WI. OTHERWISE CLEAR SKIES WERE ACROSS THE DVN CWA WHILE A LARGE MCS WAS COVERING SOUTHERN MO AHEAD OF A COLD FRONT. CURRENT TEMPERATURES IN THE DVN CWA RANGED FROM THE MID 60S TO LOWER 70S WITH DEWPOINTS IN THE UPPER 50S NW TO UPPER 60S SE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 300 AM CDT FRI JUN 28 2013 FORECAST FOCUS ON SHOWER CHANCES...CLOUD TRENDS AND TEMPERATURES. TODAY...OPERATIONAL MODELS SLIDE THE GREAT LAKES TROUGH SOUTHWARD INTO OUR REGION WITH THE RAP DEPICTING A STRONG VORT MAX MOVING FROM NORTHEAST MN INTO NORTHERN IL THIS AFTERNOON. WITH COOLING TEMPERATURES ALOFT COMBINED WITH DAYTIME HEATING INSTABILITY WILL INCREASE. HAVE CONFINED POPS TO THIS AFTERNOON AND ALSO ACROSS OUR NORTHEAST HALF CWA CLOSER TO THE TRACK OF THE VORT MAX. THE HRRR MESO MODEL DEPICTS THE POPCORN DESCRIPTION OF THE SCATTERED INSTABILITY SHOWERS (AND A FEW THUNDERSTORMS) QUITE WELL. THERE WILL BE PLENTY OF SUNSHINE FOR MOST OF THIS MORNING BUT CLOUDS WILL DEVELOP/FILL AS THE CONVECTIVE TEMPERATURE IS REACHED. MAXIMUM TEMPERATURES WILL RANGE FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH BUT HUMIDITY LEVELS WILL BE THANKFULLY LOWER COMPARED TO THE LAST FEW DAYS. TONIGHT...WITH THE UPPER TROUGH OVER THE AREA WILL CONTINUE WITH CHANCE POPS AS SKIES WILL BE MOSTLY CLOUDY OR BECOME MOSTLY CLOUDY. HOWEVER...WITH THE LOSS OF HEATING/BETTER INSTABILITY THE COVERAGE OF SHOWERS WILL DECREASE OVERNIGHT. MINIMUM TEMPERATURES SHOULD BE IN THE LOWER 60S AT MOST LOCATIONS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 300 AM CDT FRI JUN 28 2013 A DIGGING UPPER TROF OVER THE EASTERN U.S IS FORECAST TO CLOSE OFF OVER THE OHIO VALLEY BY LATE IN THE WEEKEND. THEN...MODELS ARE IN AGREEMENT THAT THE CLOSED LOW WILL RETROGRADE INTO THE MID MISSISSIPPI VALLEY EARLY IN THE WEEK AND REMAIN THERE...THEN GRADUALLY FILLING DURING THE LATTER HALF OF THE WEEK. THIS PATTERN WILL SUPPORT BELOW NORMAL TEMPERATURES THROUGH THE FORECAST PERIOD WITH HIGHS GENERALLY IN THE 70S TO AROUND 80 AND LOWS...ESPECIALLY EARLY IN THE WEEK...IN THE 50S. MOST DAYS WILL HAVE AT LEAST A LOW THREAT OF RAIN. HOWEVER...AS STATED IN THE PREVIOUS DISCUSSION...THE RAIN THREAT WILL BE LIMITED TO JUST A FEW HOURS EACH DAY. THE BETTER CHANCE OF RAIN DURING THE PERIOD WILL BE SATURDAY AS A SERIES OF S/WS DROP INTO THE DEVELOPING TROF TO OUR EAST. THE BETTER UPPER FORCING APPEARS TO BE JUST EAST OF THE FORECAST AREA...SO KEPT THE HIGHER CHANCE AND LIKELY POPS NEAR AND EAST OF THE MISSISSIPPI RIVER. THE RAIN THREAT WILL DIMINISH SATURDAY NIGHT AND SUNDAY AS DRIER LOW LEVEL AIR FILTERS IN FROM THE NORTH. THE DRY WEATHER SHOULD LAST THROUGH MONDAY THEN A LOW RAIN THREAT RETURNS MONDAY NIGHT THROUGH THE END OF THE WEEK AS THE UPPER LOW BACKS INTO THE REGION FROM THE EAST. THIS WILL SUPPORT MAINLY AFTERNOON ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS. SINCE ANY SHRA/TSRA ACTIVITY WILL PROBABLY BE TIED TO AFTERNOON HEATING...HAVE LIMITED THE POPS TO THE DAYTIME HOURS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 627 AM CDT FRI JUN 28 2013 VFR CONDS TODAY AND TONIGHT. SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP THIS AFTERNOON ACROSS PORTIONS OF EASTERN IA AND NORTHWEST IL. A FEW SHOWERS MAY LINGER INTO TONIGHT. NORTHWEST WINDS INCREASING TO 15 TO 20 KNOTS WITH GUSTS TO 25 KNOTS THIS AFTERNOON. NORTHWEST WINDS AROUND 10 KNOTS TONIGHT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...DLF AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
740 AM EDT FRI JUN 28 2013 LATEST UPDATE... UPDATE/AVIATION .SYNOPSIS... ISSUED AT 328 AM EDT FRI JUN 28 2013 CONDITIONS TODAY WILL BE FAIRLY SIMILAR TO WHAT HAPPENED DURING THE DAY ON THURSDAY. SCATTERED SHOWERS AND STORMS WILL BEGIN TO DEVELOP LATE THIS MORNING AND CONTINUE INTO THE EARLY EVENING HOURS. THE BEST CHANCE FOR RAINFALL WILL OCCUR AWAY FROM LAKE MICHIGAN. PERIODS OF SUNSHINE CAN BE EXPECTED IN BETWEEN SHOWERS THAT OCCUR. LESS IN THE WAY OF RAINFALL IS EXPECTED ON SATURDAY...ALTHOUGH THE CHANCE WILL STILL EXIST SATURDAY AFTERNOON AND EVENING. MOST LOCATIONS SHOULD STAY DRY ON SUNDAY WITH MILD TEMPERATURES WELL INTO THE 70S EXPECTED FOR HIGHS. && .UPDATE... ISSUED AT 740 AM EDT FRI JUN 28 2013 I UPDATED THE ZONES TO REFLECT THE AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NOW MOVING TOWARD MOP. THIS AREA SHOULD BE EAST OF THE CWA BY 10 AM. RAP SOUNDINGS SHOW A MOIST LAYER BETWEEN 800 AND 600 MB BEING THE KICK-0FF FOR THESE SHOWERS WITH IN COMBINATION WITH THE EDGE OF THE UPPER COLD POOL MOVING IN. THE NEXT UPSTREAM SHORTWAVE WILL MOVE INTO THE AREA BY EARLY AFTERNOON AND THE COMBINATION OF THAT THE COMBINED LAKE BREEZES FROM LAKE HURON AND LAKE MICHIGAN SHOULD KEEP THE SHOWERS AND THUNDERSTORMS MOSTLY EAST OF GRAND RAPIDS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 328 AM EDT FRI JUN 28 2013 THE MAIN FOCUS OF THE FORECAST THROUGH THE WEEKEND REMAINS CONVECTIVE TRENDS WITH THE UPPER LOW PARKED OVER THE REGION. THE GENERAL TREND OF THE FCST REMAINS MAINLY UNCHANGED. IT APPEARS THAT WE WILL HAVE SIMILAR CONDITIONS DURING THE DAY TODAY AS COMPARED TO YESTERDAY REGARDING CONVECTION POTENTIAL. CONVECTIVE DEVELOPMENT LOOKS LIKE IT WILL ONCE AGAIN BEGIN TO FIRE LATE IN THE MORNING HOURS ACROSS THE NE CORNER OF THE CWFA. THIS IS DUE TO SFC CONVERGENCE MAXIMIZED IN THAT LOCATION RESULTING FROM A SFC TROUGH THIS IS DROPPING SOUTH THROUGH THE AREA. THE SFC TROUGH IS SUPPORTED BY A LOBE OF THE NEWLY FORMED UPPER LOW DROPPING SOUTH. THE SFC CONVERGENCE/UPPER WAVE WILL BE ACTING ON ML CAPES OF 1000+ J/KG BY 18Z THIS AFTERNOON. IN ADDITION...A SOMEWHAT WRLY COMPONENT TO THE WIND WILL CONVERGE WITH A DEVELOPING LAKE BREEZE FROM LAKE HURON/SAGINAW BAY TO ONLY HELP THE CAUSE. SEVERE WEATHER IS NOT EXPECTED AS THE DEEP LAYER SHEAR IS ABOUT NIL WITH THE UPPER LOW ALMOST DIRECTLY OVER THE AREA. WE CAN EXPECT SOME PULSE TYPE STORMS WITH SOME POSSIBLE HAIL AS THE FREEZING LEVELS COME DOWN TO AROUND 11K FT OR SO. WE CAN NOT RULE OUT A DRY MICROBURST OF SOME SUB-SEVERE WINDS. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE WITH THE SLOW MOVEMENT OF ANY STORMS. THE LAKESHORE WILL HAVE THE LEAST CHC OF STORMS DUE TO THE STABILIZING EFFECTS OF LAKE MICHIGAN. WE CAN NOT RULE OUT SOMETHING SURVIVING THE TRIP FROM WISCONSIN...BUT THIS IS NOT LIKELY. THE LOBE OF THE UPPER LOW WILL ALMOST BE THROUGH THE CWFA FIRST THING ON SAT MORNING AT 12Z. IT WILL DROP SOUTH BY AFTERNOON LEAVING SOME SHORT WAVE RIDGING IN THE WAKE OVER THE CWFA. THIS COMBINED WITH SOME DRIER AIR ADVECTING IN FROM THE NE WILL LIMIT ML CAPES FROM GETTING MUCH HIGHER THAN 500 J/KG DURING THE DAY ON SAT. THE FLOW WILL BECOME NE WHICH WILL TAKE OUT THE STABILIZING EFFECTS FROM LAKE MICHIGAN. IN FACT...SOME OF THE BEST CHCS OF SHOWERS/STORMS ON SAT MIGHT BE ALONG THE LAKE BREEZE WITH THE W AND NE WINDS CONVERGING AT A GOOD ANGLE. COVERAGE AND INTENSITY SHOULD BE LOWER THAN TODAY. SEVERE WEATHER IS ONCE AGAIN NOT EXPECTED WITH SHEAR VALUES BELOW 20 KNOTS. THE THREAT FOR SHOWERS AND STORMS GOES DOWN EVEN MORE ON SUN AS EVEN DRIER AIR ADVECTS IN AT THE LOWER LEVELS. ML CAPES ARE FCST TO ONLY MAKE IT TO AROUND 200 J/KG AT BEST. THIS WILL KEEP A LID ON MOST CONVECTION THAT TRIES TO DEVELOP...EXCEPT MAYBE RIGHT ALONG THE SRN BORDER CLOSER TO THE MID LEVEL COLD POOL. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 328 AM EDT FRI JUN 28 2013 IT WOULD SEEM COOLER THAN NORMAL TEMPERATURES AND AFTERNOON AND EVENING CONVECTION WILL BE THE PRIMARY WEATHER FEATURE THROUGH THIS MOST OF THE COMING WEEK. OVERALL THERE IS GOOD MODEL AGREEMENT WITH BOTH RUN TO RUN AND MODEL TO MODEL OVER CONUS THROUGH THIS COMING WEEK. HOWEVER BY WEDNESDAY THERE IS A CURIOUS DIFFERENCE OVER EASTERN CANADA BY BETWEEN THE ECMWF AND THE GFS IN THAT THE ECMWF IS MUCH STRONGER AND DEEPER WITH SYSTEM THAT DIVES SOUTH SOUTHEAST INTO QUEBEC. THIS WOULD SUGGEST A MUCH STRONGER COLD FRONT IS HEADING SOUTH TOWARD THE NORTHERN BOARDER STATES LATE IN THE WEEK THAN SHOWN ON THE GFS. HOWEVER FOR THIS FORECAST TIME PERIOD THIS IS MORE OF A CURIOSITY THAN SOMETHING WE HAVE TO WATCH CLOSELY. THE MORE SIGNIFICANT ISSUE IS WE HAVE SPLIT FLOW OVER NORTH AMERICA WITH THE NORTHERN BRANCH NEAR 70N AND THE SOUTHERN BRANCH CLIMBING OVER THE WESTERN RIDGE NEAR 115W INTO SOUTHERN BRITISH COLUMBIA AND MANITOBA... THEN DIVING SOUTHEAST TO NEAR THE GULF COAST WEST OF MISSOURI RIVER AND THEN HEADING BACK NORTH TO NEW ENGLAND ALONG THE EAST COAST. THIS DIP IN THE JET STREAM IS ANOMALOUS FOR THIS TIME OF YEAR IS THE RESULT OF AN UPPER LOW THAT SOUTHERN GREAT LAKES THAT SLOWLY RETROGRADES WEST OF THE MISSISSIPPI RIVER BY WEDNESDAY AS SHORTWAVE ENERGY FROM THE SOUTHERN BRANCH DIVES INTO THE WESTERN SIDE OF THE LONG WAVE TROUGH. WHAT THIS DOES IS TO KEEP SOUTHWEST MICHIGAN IN OR NEAR CLOSED UPPER LOW THROUGH MOST OF THE COMING WEEK. IN SUNDAY NIGHT TO MONDAY PERIOD THE UPPER LOW IS FAR ENOUGH SOUTH AND EAST OF OUR AREA SO AS TO ALLOW FOR SOME SURFACE RIDGING AND NORTHEAST SURFACE WINDS BRINGING IN DRY SURFACE AIR. SO THAT IS A TIME WHEN THE PRECIPITATION THREAT WOULD BE LOWEST. BY TUESDAY AND WEDNESDAY AS THE SYSTEM REGRADES... THE SOUTHERLY FLOW ALOFT ON THE EAST SIDE OF THE SYSTEM BRINGS MOISTURE BACK INTO THE REGION WITH DEEP INSTABILITY THAT WILL LEAD TO LARGELY AFTERNOON AND EVENING THUNDERSTORMS. THE SHEAR REMAINS LOW SO THE SEVERE STORM THREAT IS LOW. BY JULY 4TH THE ECMWF SUGGEST UPPER RIDGING TRYING TO BUILD IN WHILE THE GFS KEEP UPPER TROUGH OVER THE AREA. BOTH MODELS BUILD IN AN UPPER RIDGE BY FRIDAY SO BY THEN IT SHOULD DRY OUT AND WARM UP SOME. THE BOTTOM LINE IS THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS IS TUE AND WEDNESDAY... THE DRIEST WEATHER SHOULD BE MONDAY AND FRIDAY. TEMPERATURES WILL RUN BELOW NORMAL THROUGH FRIDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 740 AM EDT FRI JUN 28 2013 LOW CLOUDS ARE ALREADY MIXING OUT SO VFR CIGS/VSBY ARE EXPECTED MOST OF THE DAY INTO THIS EVENING. THE PUSH OF LOW LEVEL COLD AIR IN COMBINATION WITH THE 850 MB TROUGH COMING THROUGH WILL BRING LOW CLOUDS AND SOME LIGHT FOG TO THE TAF SITES AFTER 03Z SATURDAY. I WOULD EXPECT IFR CIGS/VSBY AT MOST OF THE TAF SITES BY 10Z OR SO SATURDAY MORNING. THE CONVECTION TODAY WILL BE TO HIT AND MISS TO PUT IN THE TAFS AT THIS POINT SO I HAVE VCTS THIS AFTERNOON AND VCSH THIS EVENING. MOST OF THE CONVECTION WILL BE NEAR AND EAST OF LANSING DUE TO THE WEST NORTHWEST WIND OFF LAKE MICHIGAN PUSHING THE CONVERGENCE AREA WELL INLAND. && .MARINE... ISSUED AT 328 AM EDT FRI JUN 28 2013 NO MARINE HEADLINES ARE EXPECTED THROUGH THE WEEKEND. WE WILL SEE WINDS GENERALLY RUNNING AROUND 10 TO 15 KNOTS EACH DAY FROM TODAY THROUGH SUNDAY. THIS WILL PRODUCE WAVES OF GENERALLY 1 TO LOCALLY 3 FEET WITH THE HIGHEST WAVES EXPECTED SOUTH DUE TO THE NRLY FETCH. && .HYDROLOGY... ISSUED AT 328 AM EDT FRI JUN 28 2013 NO WIDESPREAD HYDROLOGY HEADLINES EXPECTED THROUGH EARLY NEXT WEEK. WE WILL HAVE TO WATCH FOR SOME LOCALLY HEAVY RAINS FOR TODAY... ALTHOUGH THE THREAT IS A LITTLE LOWER COMPARED TO THU. WE WILL SEE DIURNAL SHOWERS AND STORMS DEVELOP ONCE AGAIN WITH VERY SLOW MOVEMENT EXPECTED DUE TO THE LACK OF WIND IN THE CLOUD LAYER. PRECIPITABLE WATER HAS DROPPED A LITTLE AS THE BEST MOISTURE AXIS HAS MOVED AWAY AND DRIER AIR IS SLOWLY FILTERING IN. SOME FLOOD ADVISORIES WILL BE POSSIBLE WHERE CONVECTION SITS FOR LONGER PERIOD OF TIMES. THE THREAT WILL BECOME MUCH LOWER FOR THE REMAINDER OF THE WEEKEND. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...WDM AVIATION...WDM HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
929 AM MDT FRI JUN 28 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY... SENT AN UPDATE THIS MORNING FOR SOME VERY MINOR CHANGES. CHOSE TO SCALE BACK THE SLIGHT CHANCE POPS TOWARD THE NORTHEAST TO NOT COVER AS MUCH OF THE CWA...FOLLOWING THE MOST RECENT HI-RES MODEL UPDATES. MADE OTHER SMALL ADJUSTMENTS TO SKY COVER...TEMPS...AND WINDS. IT WILL BE VERY INSTRUCTIVE AND TELLING TO SEE IF THE ISOLATED SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO BEING RESOLVED IN THE HI-RES MODELS...THE HRRR FOR EXAMPLE...ACTUALLY RESULT IN SOME PRECIPITATION REACHING THE GROUND TODAY...OR IF IT WILL JUST BE VIRGA SHOWERS. I WILL MAKE A FEW PHONE CALLS TO TRY AND GET SOME GROUND TRUTH IN ORDER TO ASCERTAIN THE APPROPRIATE LEVEL OF MODEL CONFIDENCE. BMICKELSON PREVIOUS SHORT TERM DISCUSSION...UPPER RIDGE CURRENTLY COVERING THE WESTERN HALF OF THE U.S. WILL REMAIN IN PLACE FOR THE MOST PART THROUGH THE WEEKEND. THE RIDGE WILL GAIN SOME AMPLITUDE WITH THE TOP OF THE RIDGE MOVING NORTH TODAY AND SATURDAY. WITH ONE EXCEPTION...EXPECT DRY WEATHER THROUGH SATURDAY WITH TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL. WINDS WILL BE SOMEWHAT LIGHTER TODAY THAN YESTERDAY AS SURFACE HIGH MOVES THROUGH EASTERN MONTANA. THE EXCEPTION TO THE DRY WEATHER WILL BE A WEAK SHORTWAVE TODAY THAT MOVES ACROSS THE TOP OF THE RIDGE IN SOUTHERN ALBERTA AND GOES THROUGH THE NE CORNER OF MONTANA THIS AFTERNOON. IT LOOKS LIKE THERE WILL BE THE POSSIBILITY OF THE ATMOSPHERE BEING UNSTABLE ENOUGH IN THE NORTHEAST ZONES THIS AFTERNOON THAT A FEW ISOLATED THUNDERSTORMS COULD DEVELOP. WILL ADD THAT TO THE FORECAST FOR THIS AFTERNOON. WINDS WILL TURN TO THE EAST OR SOUTHEAST TONIGHT AND SATURDAY AS THE SURFACE HIGH MOVES TO THE EAST AND LEE SIDE TROUGH DEVELOPS OVER CENTRAL MONTANA. AIR MASS IN CENTRAL MONTANA WILL BE SOMEWHAT UNSTABLE ON SATURDAY WHICH WILL ALLOW SOME MOUNTAIN BASED CONVECTION TO DEVELOP. AT THIS POINT...IT LOOKS LIKE ANY STORMS THAT DO DEVELOP IN THE MOUNTAINS ON SATURDAY WILL DISSIPATE BEFORE REACHING NORTHEAST MONTANA WITH AIR MASS BEING STABLE THERE. ON SUNDAY...A SHORTWAVE MOVING THROUGH ALBERTA WILL FLATTEN THE RIDGE SOMEWHAT. AIR MASS BECOMES SOMEWHAT UNSTABLE IN NORTHEAST MONTANA IN THE AFTERNOON WHICH WILL GIVE ANY STORMS THAT DEVELOP IN THE MOUNTAINS TO THE WEST A BETTER CHANCE OF HOLDING TOGETHER AS THEY MOVE TO THE EAST. WILL MENTION A SLIGHT CHANCE OF THUNDERSTORMS IN THE AFTERNOON. FORRESTER .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... SUNDAY NIGHT THROUGH TUESDAY...MODEL GUIDANCE IS IN EXCELLENT AGREEMENT KEEPING A HIGHLY AMPLIFIED UPPER LEVEL RIDGE ACROSS THE WESTERN U.S. LEADING TO LARGE SCALE SUBSIDENCE AND THEREFORE DRY CONDITIONS FOR NORTHEAST MONTANA. INCLUDED A SLIGHT CHANCE POPS MENTION IS SOME LOCATIONS WHERE MINOR DISTURBANCES MAY LEAD TO ENHANCED VERTICAL ASCENT AS THEY PROPAGATE THROUGH IN NORTHERLY FLOW ALOFT THROUGH THE CWA ON THE EASTERN PERIPHERY OF THE RIDGE. WILL EXPECT SEASONAL TO A FEW DEGREES ABOVE SEASONAL TEMPERATURES WITH THE FORECAST REGION SITUATED IN THIS RIDGING PATTERN ALONG WITH RISING 850MB TEMPERATURES. TUESDAY NIGHT AND BEYOND...AN UPPER LEVEL SHORTWAVE FEATURE IS ADVERTISED IN BOTH THE 00Z ECMWF AND GFS TO DIVE DOWN FROM SASKATCHEWAN AND INTO THE DAKOTAS BEFORE RETROGRADING TOWARD NORTHEAST MONTANA. THE LARGE SCALE RIDGING WILL ERODE ONLY VERY GRADUALLY AND WILL OFFER GREAT RESISTANCE TO THIS SHORTWAVE FEATURE. THEREFORE NOT OVERLY EXCITED ABOUT INSERTING HIGHER POPS INTO THE GRIDS AT THIS TIME. HOWEVER...DID FEEL COMFORTABLE MAKING SOME REFINEMENTS IN THAT FROM THE MIDDLE OF THE WEEK ONWARD...THE HIGHEST POPS ARE INCLUDED IN THE EASTERN ZONES...WITH POPS TRENDING DOWN TO SLIGHT CHANCE MENTION OR LOWER FURTHER TO THE WEST. BY THE END OF THE WEEK...CONFINED MENTION TO JUST THE SOUTHERN ZONES TRENDED TEMPERATURES DOWN IN THE MIDDLE PORTION OF NEXT WEEK WITH LOWERING 850MB TEMPERATURES AND DECREASING THICKNESSES IN THE EASTERN ZONES AS THE UPPER LEVEL SHORTWAVE MAKES A PENETRATION INTO THE RIDGING. MODELS DO BEGIN TO INDICATE A RETURN OF AN UPPER LEVEL RIDGE DEVELOPING BY THE END OF NEXT WEEK OR THE WEEKEND...BUT GIVEN HOW FAR OUT THAT IS IN THE FORECAST PERIOD...WILL NOT CONCERN OVER THE DETAILS RIGHT NOW. DID TICK TEMPERATURES UPWARD JUST A TOUCH ON FRIDAY THOUGH TO REFLECT THIS IDEA. IT IS SURPRISING HOWEVER THAT THERE IS SUCH EXCELLENT MODEL AGREEMENT THIS FAR OUT AND THAT AT LEAST LEADS TO HIGH CONFIDENCE IN THE EXTENDED FORECAST. ONE THING OF INTEREST TO CONSIDER THOUGH LATE NEXT WEEK OR WEEKEND IS MODELS BRINGING IN AN UPPER TROUGH PUSHING INTO THE PACIFIC COAST WHICH COULD EVENTUALLY MEAN SOUTHWEST FLOW ALOFT HERE IN NE MT. THIS WOULD LEAD TO SOMEWHAT MORE UNSETTLED CONDITIONS THAN THAT EXPECTED WITH A RIDGE PARKED OVER THE AREA. WILL BE LOOKING TO SEE HOW MODELS HANDLE THE PROGRESSION OF THAT TROUGH IN THE VERY LATE EXTENDED OVER THE COURSE OF THE NEXT SEVERAL DAYS. WAY DOWN THE ROAD...THIS MAY PROVIDE THE CWA WITH THE NEXT MEANINGFUL CHANCE OF UNSETTLED CONDITIONS. GIVEN THAT THIS IS 7 TO 10 DAYS OUT THOUGH...THIS IS MERELY SPECULATION AT THIS POINT. ALTHOUGH THERE ARE CONTRASTS THAT CAN BE MADE ABOUT THE OVERALL SHAPE AND SOME OF THE SPATIAL AND TEMPORAL CHARACTERISTICS OF THE SYNOPTIC SCALE PATTERN BY NEXT WEEKEND...IT IS QUITE INTERESTING TO SEE THE SIMILARITIES IN BOTH THE ECMWF AND GFS SOLUTIONS EVEN THIS FAR OUT IN THE FORECAST PERIOD. MALIAWCO && .AVIATION... DUE TO A LARGE RIDGE OVER MUCH OF THE U.S....VFR CONDITIONS WILL PREVAIL AT THE TERMINAL LOCATIONS TODAY AND TONIGHT WITH ONLY A VERY OUTSIDE CHANCE FOR AN AFTERNOON SHOWER. LIGHT AND VARIABLE WINDS EARLY THIS MORNING WILL INCREASE FROM THE NORTHWEST BY THE AFTERNOON TO BETWEEN 10 AND 15 KTS. MALIAWCO/MARTIN && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1145 AM EDT FRI JUN 28 2013 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL REMAIN OVER THE REGION THROUGH THE WEEKEND. THIS SYSTEM WILL PRODUCE SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD WITH THE MOST WIDESPREAD COVERAGE OCCURRING DURING THE DAYLIGHT HOURS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED AT 1145 AM... SURFACE LOW PRESSURE DOWN TO 996 MB OVER NORTHEAST NY MOVING NORTHEAST. MAIN CONCERN OVER THE NEXT SEVERAL HOURS WILL BE FOR POTENTIAL FOR SHOWERS AND THUNDERSTORMS PRODUCING ISOLATED FLASH FLOODING THIS AFTERNOON ALONG WITH A SEVERE THREAT. SATELLITE LOOPS INDICATE THAT PARTIAL CLEARING IS DEVELOPING ACROSS MUCH OF PA THIS MORNING WITH CLOUDY SKIES CONTINUING ACROSS NY STATE. 12Z BUF SOUNDING SHOWS A BIT OF A WARM LAYER AT 700 MB AND ANOTHER WEAK WARM LAYER UP AROUND 500 MB... SO OVERALL MID-LEVEL LAPSE RATES ARE NOT STEEP. HOWEVER MID-LEVEL WINDS ARE RATHER STRONG WITH 40 KTS SHOWN FROM 700 TO 500 MB. SFC DEW POINTS REMAIN IN THE MID 60S WITH A WEAK SURFACE TROUGH MOVING IN FROM THE WEST. KEY FOR STRONG THUNDERSTORM DEVELOPMENT THIS AFTERNOON WILL BE AMOUNT OF SUNSHINE AND DESTABILIZATION THAT MIGHT OCCUR. LATEST 12Z NAM IS STILL NOT VERY IMPRESSED WITH THE INSTABILITY INDICATING CAPES OF 500 J/KG OR LESS. HOWEVER THE LATEST RAP AND LAST NIGHTS GFS SHOW MORE INSTABILITY WITH CAPES UP NEAR OR JUST OVER 1000 J/KG FROM THE SOUTHERN TIER OF NY SOUTH INTO PA. GIVEN THAT CLEARING IS ALREADY OCCURRING ACROSS MUCH OF PA SUSPECT THAT CAPES PROBABLY WILL AT LEAST APPROACH 1000 J/KG ACROSS NE PA THIS AFTERNOON... AND SOME STRONG THUNDERSTORMS WILL PROBABLY DEVELOP. FARTHER NORTH CLEARING IS LESS CERTAIN SO EXPECTING SHOWERS WITH ISOLATED THUNDER. GIVEN MODERATELY MOIST ATMOSPHERE ANY STORM COULD PRODUCE A QUICK INCH OF RAIN WHICH WOULD BE ENOUGH TO CAUSE ISOLATED FLASH FLOODING... SO AM PLANNING ON EXTENDING THE WATCH INTO EARLY THIS EVENING. ISOLATED SEVERE STORMS ALSO APPEAR TO BE POSSIBLE THIS AFTERNOON ESPECIALLY IN NORTHEAST PA WHERE HEATING WILL INCREASE THE INSTABILTY. PREVIOUS DISCUSSION BELOW. 630 AM UPDATE...MODERATE TO HEAVY RAIN NOW CONFINED TO NORTHERN ONEIDA COUNTY AND THIS WILL LIFT NORTH OF THE AREA BY 8 AM. NEXT BATCH OF SHOWERS/THUNDERSTORMS ASSOCIATED WITH FRONT END OF UPPER LEVEL LOW NOW MOVING INTO WESTERN NEW YORK. THIS WILL BEGIN SPREADING ACROSS WRN PTN OF FA BY MID MORNING. ONLY MINOR ADJUSTMENTS NEEDED TO POP GRIDS. AT 445 AM...SFC LOW PRES WAS LIFTING NORTH THROUGH EASTERN NEW YORK WITH LOCAL RADARS SHOWING MODERATE TO HEAVY RAINFALL ACROSS THE WESTERN MOHAWK VALLEY AND THE NORTHERN SUSQUEHANNA REGION. THE HEAVY PRECIP ON THE BACK SIDE OF THIS LOW WILL GRADUALLY LIFT NORTH OF THE REGION BY MID MORNING. FLASH FLOOD WARNINGS ARE CURRENTLY IN EFFECT FOR MUCH OF THIS AREA. FOR TODAY, UPPER LEVEL LOW OVER THE NRN GREAT LAKES WILL DROP SOUTHEAST INTO THE EASTERN LAKES. MID LEVEL SHORT WAVES ROTATING AROUND THE FEATURE WILL GENERATE MORE WIDESPREAD SHOWERS AND THUNDERSTORMS FROM LATE THIS MORNING THROUGH THE AFTERNOON. ATMOSPHERE REMAINS VERY MOIST WITH PWATS AROUND 1.50-1.75 INCHES, THEREFORE ANY CONVECTION WILL HAVE THE POTENTIAL FOR TORRENTIAL DOWNPOURS. MODEL SOUNDINGS INDICATE CAPE VALUES OF 500-1000 J/KG WHICH WILL ENHANCE CONVECTIVE ACTIVITY UNDER THE UPPER LEVEL FEATURE. WILL CONTINUE WITH FLASH FLOOD WATCH THROUGH THIS AFTERNOON DUE TO ADDITIONAL CONVECTIVE RAINFALL FALLING ON SATURATED SOILS ESPECIALLY OVER CENTRAL NEW YORK EAST OF INTERSTATE 81 AND NORTHEAST PENNSYLVANIA. THERE IS THE POTENTIAL THAT A FEW STORMS COULD BECOME SEVERE BUT ONE AGAIN LAPSE RATES, CAPE VALUES AND MID LEVEL WIND FIELDS ARE VERY MARGINAL. IF SVR CONVECTION DOES OCCUR IT WOULD MOST LIKELY BE OVER THE SOUTHERN CATSKILLS AND POCONOS. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... TONIGHT THROUGH SUNDAY NIGHT...H5 UPPER LEVEL TROF WILL REMAIN JUST WEST OF FA THROUGH SUNDAY NIGHT WITH AIRMASS REMAINING FAIRLY MOIST. CONVECTIVE ACTIVITY WILL PERSIST THROUGH THE PERIOD WITH THE MOST WIDESPREAD ACTIVITY OCCURRING DURING THE DAYLIGHT HOURS ENHANCED BY DIURNAL HEATING. AIRMASS BECOMES EVEN MORE MOISTURE LADEN SUNDAY/SUNDAY NIGHT AS FULL LATITUDE UPPER LEVEL TROF BEGINS TO TAP MORE GULF MOISTURE. A VERY WET PERIOD AHEAD WITH THE CONTINUED POTENTIAL FOR LOCALIZED HEAVY RAINS. MAX TEMPS WILL GENERALLY RANGE FROM THE MID 70S INTO THE LOW 80S. && .LONG TERM /MONDAY THROUGH THURSDAY/... 1 PM THU DISC... GLOBAL MODEL/WPC CONSENSUS CONTS TO SUGGEST QUITE AN AMPLIFIED PATN FOR THIS TIME OF YEAR...WITH A SIG WRN CONUS/CANADIAN RIDGE...AND ERN CONUS TROUGH. THIS LIKELY SPELLS A WET PATN FOR NY/PA...WITH A SUSTAINED DEEP SRLY FLOW...AND LIKELY S/WV IMPULSES RIDING NWD/NEWD UP THE FRONT SIDE OF THE AFOREMENTIONED TROUGH AXIS. THUS...SCTD-NUMEROUS/LIKELY POPS WILL BE RETAINED FOR MUCH OF THE PD. ALTHOUGH MUGGY CONDS ARE FORESEEN...PERSISTENT PCPN SHOULD KEEP HIGH TEMPS IN THE 70S-LWR 80S EACH DAY. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... 700 AM EDT UPDATE... ANOTHER CHALLENGING FORECAST IS IN STORE FOR TODAY. HEAVY RAIN SHOWERS ARE CURRENTLY MOVING NE AWAY OF CENTRAL NY THIS MORNING AND IFR CIGS HAVE SETTLED OVER THE REGION IN THE WAKE OF THE SHOWERS. IFR CIGS SHOULD MIX OUT OVER THE NEXT COUPLE OF HOURS AND RETURN TO VFR. THE NEXT ROUND OF SHOWERS ARE STARTING TO MOVE INTO CENTRAL NY THIS MORNING. THESE SHOWERS ARE EXPECTED TO FILL IN AND BE SCATTERED LIKE TODAY THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THIS ACTIVITY SHOULD MOVE OUT OF THE REGION BY 4Z TONIGHT. THERE IS THE POSSIBILITY OF IFR CONDITIONS AGAIN FRIDAY NIGHT INTO SATURDAY MORNING...HOWEVER CONFIDENCE IS LOW SO KEPT OUT OF TAFS FOR THE TIME BEING. OUTLOOK...SAT THROUGH TUE... SAT THROUGH TUE... OCNL RESTRICTIONS ARE LIKELY EACH DAY...WITH SHRA/TSRA IN THE VICINITY. THE MOST PERSISTENT RESTRICTIONS MAY COME BY MON/MON NGT. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...FLASH FLOOD WATCH UNTIL 2 PM EDT THIS AFTERNOON FOR PAZ038>040- 043-044-047-048-072. NY...FLASH FLOOD WATCH UNTIL 2 PM EDT THIS AFTERNOON FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...RRM NEAR TERM...MSE/RRM SHORT TERM...RRM LONG TERM...MLJ AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
955 AM EDT FRI JUN 28 2013 .SYNOPSIS... LOW PRESSURE WILL SLOWLY LIFT ACROSS EASTERN NEW YORK TODAY...WITH THIS SYSTEM EXPECTED TO STALL ACROSS THE REGION AS IT GRADUALLY WEAKENS THROUGH THE WEEKEND. THIS WILL BRING PERIODS OF RAIN TODAY...WITH EMBEDDED AREAS OF HEAVIER RAIN AND THUNDERSTORMS. THE THREAT FOR SHOWERS AND PERHAPS A THUNDERSTORM WILL PERSIST THROUGH THE WEEKEND...HOWEVER SHOWERS WILL BECOME INCREASINGLY MORE SCATTERED AS THE WEEKEND WEARS ON. && .NEAR TERM /THROUGH TONIGHT/... FLOOD POTENTIAL CONTINUES ACROSS THE REGION TODAY. THERE ARE TWO MAIN FEATURES TO WATCH TODAY...WITH THE MOST OBVIOUS BEING THE LARGE AREA OF RAIN ASSOCIATED WITH THE WEAK SURFACE LOW WHICH IS LIFTING ACROSS EASTERN NEW YORK STATE. THROUGH DAYBREAK...RADAR SHOWS THE HEAVIEST RAIN TO THE EAST OF OUR CWA. STEADY RAINS SHOULD BRING AROUND AN INCH TO LEWIS COUNTY...WITH LESS TO THE WEST OF THIS. FLOOD POTENTIAL APPEARS TO BE DIMINISHING EAST OF LAKE ONTARIO...HOWEVER UPSTREAM RAINS WILL LIKELY CAUSE THE BLACK RIVER TO RISE AT BOONVILLE...PROBABLY APPROACHING BUT FALLING JUST SHY OF FLOOD STAGE. THE SECOND FEATURE IS A MORE SUBTLE UPPER LEVEL TROF AXIS WHICH EXTENDS FROM WESTERN NEW YORK BACK INTO SOUTHERN ONTARIO TO GEORGIAN BAY. SHOWERS ALONG THIS AXIS ARE FORECAST TO CONTINUE TO EXPAND THIS MORNING BY THE HRRR. SEVERAL RUNS OF THE NAM/RGEM SUPPORT THE HRRR FORECAST AND GIVEN ITS FAIRLY GOOD TRACK RECORD FOR THIS EVENT AS WELL AS RADAR TRENDS...WE HAVE INCREASING CONFIDENCE IN THE FORECAST. SHOWERS WITH EMBEDDED THUNDERSTORMS SHOULD CONTINUE TO EXPAND ACROSS WESTERN NEW YORK THIS MORNING THEN LIFT GRADUALLY NORTHEAST THIS AFTERNOON. THIS PRECIPITATION WILL BE CONVECTIVE...WITH BUFKIT SHOWING A MOIST SOUNDING WITH THIN AND NARROW CAPES...AND P-WAT VALUES AROUND 1.6 INCHES. CONSENSUS QPFS FROM THE HIGHER RESOLUTION MODELS INCLUDING RECENT RUNS OF THE NAM/RGEM/SREF ONLY AVERAGE AROUND AN INCH WITH THIS. HOWEVER...GIVEN THE SLOW MOTION OF THE CONVECTIVE CELLS...LOCALLY HIGHER AMOUNTS ARE POSSIBLE. RAIN AMOUNTS IN EXCESS OF TWO INCHES WOULD BE A CONCERN PRETTY MUCH ANYWHERE...WITH URBAN AREAS...THE BUFFALO CREEKS...AND AREAS WITH RECENT RAINS VULNERABLE TO LESSER RAINFALL AMOUNTS. FOLLOWING THIS...WILL MAINTAIN THE FLOOD WATCH...WITH A KEEN FOCUS ON SHOWERS DEVELOPING ACROSS SOUTHERN ONTARIO AND EASTERN LAKE ERIE. THE UPPER LOW WILL GRADUALLY MOVE ACROSS THE REGION TONIGHT...WHICH WILL EFFECTIVELY END THIS AXIS OF FOCUS AS THE LOW BECOMES VERTICALLY STACKED. THERE WILL BE A LINGERING THREAT FOR SHOWERS TONIGHT...WITH SHOWERS EXPECTED TO BECOME INCREASINGLY SCATTERED IN NATURE AS THE NIGHT GOES ON. WHILE WIDESPREAD THUNDERSTORMS ARE NOT LIKELY...THERE MAY BE SOME EMBEDDED IN AREAS OF HEAVY RAIN TODAY AND INTO THIS EVENING. TEMPERATURES WILL NOT RISE VERY MUCH AT ALL TODAY...WITH PERSISTENT CLOUDS COVER AND AREAS OF SHOWERS. EXPECT HIGHS TO ONLY BE AROUND 70 DEGREES IN MOST LOCATIONS. OVERNIGHT LOWS SHOULD DROP INTO THE UPPER 50S TO LOWER 60S. PATCHY FOG IS LIKELY...AND WHILE MOSTLY CLOUDY SKIES ARE EXPECTED...ANY CLEARING WOULD QUICKLY FAIRLY DENSE FOG DEVELOPMENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A FULL LATITUDE TROUGH IS FORECAST TO REMAIN IN PLACE FROM SOUTHERN QUEBEC TO THE TENNESSEE VALLEY THROUGH THIS PERIOD. THE DEEP LAYERED SOUTHERLY FLOW WILL KEEP MOIST AND SOMEWHAT UNSTABLE AIR OVER OUR AREA WHICH WILL LEAD TO OCCASIONAL SHOWERS AND SCATTERED THUNDERSTORMS. THE MODELS AGREE THAT A LOW LEVEL TROUGH/BAROCLINIC ZONE WILL REMAIN STALLED OVER CENTRAL NEW YORK STATE. THIS BOUNDARY WILL HELP TO FOCUS THE MOISTURE WHICH COULD LEAD TO ENHANCED RAINFALL AT TIMES. IN ADDITION...A SERIES OF SHORT WAVES WILL BE LIFTING NORTH THROUGH THE EASTERN FLANK OF THE UPPER LEVEL TROUGH...BUT THE TIMING OF THESE IMPULSES CANNOT BE PINNED DOWN AT THIS TIME. AS A RESULT...WILL FOLLOW THE PREVIOUS TREND OF INDICATING HIGHER POPS DURING THE AFTERNOON WHEN DAYTIME HEATING WILL LEAD TO A BETTER CHANCE FOR A FEW THUNDERSTORMS. ALL OF THESE FACTORS COULD LEAD TO A POTENTIAL FOR MORE FLOODING ISSUES...ESPECIALLY WITH THE ANTECEDENT MOISTURE THAT WILL BE IN PLACE FROM PREVIOUS RAINFALL. ABUNDANT CLOUD COVER AND SHOWER ACTIVITY ALONG WITH SLIGHTLY COOLER AIR ALOFT DUE TO THE PRESENCE OF THE UPPER LEVEL TROUGH WILL HELP KEEP TEMPERATURES SLIGHTLY BELOW AVERAGE DURING THIS PERIOD. && .LONG TERM /MONDAY THROUGH THURSDAY/... A DEEP UPPER LEVEL TROUGH EXTENDING FROM JAMES BAY ACROSS THE GREAT LAKES DOWN TO THE CENTRAL GULF COAST WILL GRADUALLY RETROGRADE WEST TO THE MISSISSIPPI VALLEY AS THE BERMUDA HIGH REASSERTS IT/S DOMINANCE OVER THE WESTERN ATLANTIC. THE PRESENCE OF A DEEP LAYERED SOUTHERLY FLOW AND AN ABUNDANT SUPPLY OF LOW LEVEL MOISTURE WILL KEEP WESTERN AND NORTH CENTRAL NEW YORK IN A FAVORABLE POSITION FOR UNSETTLED WEATHER THROUGH MUCH OF THE UPCOMING WEEK. THE BULK OF PRECIPITATION WILL BE IN THE FORM OF DIURNALLY DRIVEN CONVECTION WITH SHOWERS AND THUNDERSTORMS BREAKING OUT IN THE AFTERNOON AND EVENING HOURS EACH DAY. TEMPERATURES DURING THE PERIOD WILL SHOW A SLOW MODERATING TREND AS THE UPPER LEVEL TROUGH SLIDES WEST AND SOMEWHAT WARMER AIR OVER THE EAST COAST PUSHES BACK INTO THE LOWER GREAT LAKES. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... MAINLY IFR CONDITIONS PERSIST ACROSS THE REGION THIS MORNING WITH LOW CIGS AND VSBYS IN A VERY MOIST ATMOSPHERE. ACROSS THE EAST...A STEADY AREA OF RAIN OVER THE NORTH COUNTRY WILL SLOWLY LIFT NORTH ALLOWING FOR A SLOW IMPROVEMENT IN CONDS AT KART. ELSEWHERE...SHOWERS WITH EMBEDDED THUNDERSTORMS SHOULD EXPAND RESULTING IN VARIABLE CONDITIONS...OCCASIONALLY IFR OR LESS IN HEAVIER RAINS. SHOWERS SHOULD BE VERY SLOW MOVING. ALTHOUGH SHOWERS SHOULD TAPER OFF LATER TONIGHT...SIGNIFICANT LOW MOISTURE...AND LESS MOISTURE ALOFT WILL LIKELY LEAD TO FAIRLY WIDESPREAD IFR OR LOWER CONDITIONS. ANY CLEARING ALOFT WOULD LIKELY RESULT IN SOME FAIRLY DENSE GROUND FOG. OUTLOOK... SATURDAY THROUGH TUESDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NNE WINDS TO PICK UP THIS MORNING. CONDITIONS WILL BECOME A BIT CHOPPY...BUT WAVES ARE EXPECTED TO REMAIN BELOW SCA CRITERIA. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ006>008. FLOOD WATCH THROUGH THIS EVENING FOR NYZ001>005-010>014- 019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL/LEVAN SHORT TERM...TJP LONG TERM...TJP/WOOD AVIATION...APFFEL/LEVAN MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
715 AM EDT FRI JUN 28 2013 .SYNOPSIS... LOW PRESSURE WILL SLOWLY LIFT ACROSS EASTERN NEW YORK TODAY...WITH THIS SYSTEM EXPECTED TO STALL ACROSS THE REGION AS IT GRADUALLY WEAKENS THROUGH THE WEEKEND. THIS WILL BRING PERIODS OF RAIN TODAY...WITH EMBEDDED AREAS OF HEAVIER RAIN AND THUNDERSTORMS. THE THREAT FOR SHOWERS AND PERHAPS A THUNDERSTORM WILL PERSIST THROUGH THE WEEKEND...HOWEVER SHOWERS WILL BECOME INCREASINGLY SCATTERED AS THE WEEKEND WEARS ON. && .NEAR TERM /THROUGH TONIGHT/... THERE CONTINUES TO BE A POTENTIAL FOR FLOODING ACROSS PORTIONS OF WESTERN NEW YORK TODAY. THERE APPEARS TO BE TWO MAIN FEATURES TO WATCH TODAY...WITH THE MOST OBVIOUS BEING THE LARGE AREA OF RAIN ASSOCIATED WITH THE WEAK SURFACE LOW WHICH IS LIFTING ACROSS EASTERN NEW YORK STATE. THROUGH DAYBREAK...RADAR SHOWS THE HEAVIEST RAIN TO THE EAST OF OUR CWA. STEADY RAINS SHOULD BRING AROUND AN INCH TO LEWIS COUNTY...WITH LESS TO THE WEST OF THIS. FLOOD POTENTIAL APPEARS TO BE DIMINISHING EAST OF LAKE ONTARIO...HOWEVER UPSTREAM RAINS WILL LIKELY CAUSE THE BLACK RIVER TO RISE AT BOONVILLE...PROBABLY APPROACHING BUT FALLING JUST SHY OF FLOOD STAGE. THE SECOND FEATURE WE WILL BE KEEPING A CLOSE EYE ON IS A MORE SUBTLE UPPER LEVEL TROF AXIS WHICH EXTENDS FROM WESTERN NEW YORK BACK INTO SOUTHERN ONTARIO TO GEORGIAN BAY. SHOWERS ALONG THIS AXIS ARE FORECAST TO CONTINUE TO EXPAND THIS MORNING BY THE HRRR. SEVERAL RUNS OF THE NAM/RGEM SUPPORT THE HRRR FORECAST AND GIVEN ITS FAIRLY GOOD TRACK RECORD FOR THIS EVENT AS WELL AS RADAR TRENDS...WE HAVE INCREASING CONFIDENCE IN THE FORECAST. SHOWERS WITH EMBEDDED THUNDERSTORMS SHOULD CONTINUE TO EXPAND ACROSS WESTERN NEW YORK THIS MORNING THEN LIFT GRADUALLY NORTHEAST THIS AFTERNOON. THIS PRECIPITATION WILL BE CONVECTIVE...WITH BUFKIT SHOWING A MOIST SOUNDING WITH THIN AND NARROW CAPES...AND P-WAT VALUES AROUND 1.6 INCHES. CONSENSUS QPFS FROM THE HIGHER RESOLUTION MODELS INCLUDING RECENT RUNS OF THE NAM/RGEM/SREF ONLY AVERAGE AROUND AN INCH WITH THIS. HOWEVER...GIVEN THE SLOW MOTION OF THE CONVECTIVE CELLS...LOCALLY HIGHER AMOUNTS ARE POSSIBLE. RAIN AMOUNTS IN EXCESS OF TWO INCHES WOULD BE A CONCERN PRETTY MUCH ANYWHERE...WITH URBAN AREAS...THE BUFFALO CREEKS...AND AREAS WITH RECENT RAINS VULNERABLE TO LESSER RAINFALL AMOUNTS. FOLLOWING THIS...WILL MAINTAIN THE FLOOD WATCH...WITH A KEEN FOCUS ON SHOWERS DEVELOPING ACROSS SOUTHERN ONTARIO AND EASTERN LAKE ERIE. THE UPPER LOW WILL GRADUALLY MOVE ACROSS THE REGION TONIGHT...WHICH WILL EFFECTIVELY END THIS AXIS OF FOCUS AS THE LOW BECOMES VERTICALLY STACKED. THERE WILL BE A LINGERING THREAT FOR SHOWERS TONIGHT...WITH SHOWERS EXPECTED TO BECOME INCREASINGLY SCATTERED IN NATURE AS THE NIGHT GOES ON. WHILE WIDESPREAD THUNDERSTORMS ARE NOT LIKELY...THERE MAY BE SOME EMBEDDED IN AREAS OF HEAVY RAIN TODAY AND INTO THIS EVENING. TEMPERATURES WILL NOT RISE VERY MUCH AT ALL TODAY...WITH PERSISTENT CLOUDS COVER AND AREAS OF SHOWERS. EXPECT HIGHS TO ONLY BE AROUND 70 DEGREES IN MOST LOCATIONS. OVERNIGHT LOWS SHOULD DROP INTO THE UPPER 50S TO LOWER 60S. PATCHY FOG IS LIKELY...AND WHILE MOSTLY CLOUDY SKIES ARE EXPECTED...ANY CLEARING WOULD QUICKLY FAIRLY DENSE FOG DEVELOPMENT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A FULL LATITUDE TROUGH IS FORECAST TO REMAIN IN PLACE FROM SOUTHERN QUEBEC TO THE TENNESSEE VALLEY THROUGH THIS PERIOD. THE DEEP LAYERED SOUTHERLY FLOW WILL KEEP MOIST AND SOMEWHAT UNSTABLE AIR OVER OUR AREA WHICH WILL LEAD TO OCCASIONAL SHOWERS AND SCATTERED THUNDERSTORMS. THE MODELS AGREE THAT A LOW LEVEL TROUGH/BAROCLINIC ZONE WILL REMAIN STALLED OVER CENTRAL NEW YORK STATE. THIS BOUNDARY WILL HELP TO FOCUS THE MOISTURE WHICH COULD LEAD TO ENHANCED RAINFALL AT TIMES. IN ADDITION...A SERIES OF SHORT WAVES WILL BE LIFTING NORTH THROUGH THE EASTERN FLANK OF THE UPPER LEVEL TROUGH...BUT THE TIMING OF THESE IMPULSES CANNOT BE PINNED DOWN AT THIS TIME. AS A RESULT...WILL FOLLOW THE PREVIOUS TREND OF INDICATING HIGHER POPS DURING THE AFTERNOON WHEN DAYTIME HEATING WILL LEAD TO A BETTER CHANCE FOR A FEW THUNDERSTORMS. ALL OF THESE FACTORS COULD LEAD TO A POTENTIAL FOR MORE FLOODING ISSUES...ESPECIALLY WITH THE ANTECEDENT MOISTURE THAT WILL BE IN PLACE FROM PREVIOUS RAINFALL. ABUNDANT CLOUD COVER AND SHOWER ACTIVITY ALONG WITH SLIGHTLY COOLER AIR ALOFT DUE TO THE PRESENCE OF THE UPPER LEVEL TROUGH WILL HELP KEEP TEMPERATURES SLIGHTLY BELOW AVERAGE DURING THIS PERIOD. && .LONG TERM /MONDAY THROUGH THURSDAY/... A DEEP UPPER LEVEL TROUGH EXTENDING FROM JAMES BAY ACROSS THE GREAT LAKES DOWN TO THE CENTRAL GULF COAST WILL GRADUALLY RETROGRADE WEST TO THE MISSISSIPPI VALLEY AS THE BERMUDA HIGH REASSERTS IT/S DOMINANCE OVER THE WESTERN ATLANTIC. THE PRESENCE OF A DEEP LAYERED SOUTHERLY FLOW AND AN ABUNDANT SUPPLY OF LOW LEVEL MOISTURE WILL KEEP WESTERN AND NORTH CENTRAL NEW YORK IN A FAVORABLE POSITION FOR UNSETTLED WEATHER THROUGH MUCH OF THE UPCOMING WEEK. THE BULK OF PRECIPITATION WILL BE IN THE FORM OF DIURNALLY DRIVEN CONVECTION WITH SHOWERS AND THUNDERSTORMS BREAKING OUT IN THE AFTERNOON AND EVENING HOURS EACH DAY. TEMPERATURES DURING THE PERIOD WILL SHOW A SLOW MODERATING TREND AS THE UPPER LEVEL TROUGH SLIDES WEST AND SOMEWHAT WARMER AIR OVER THE EAST COAST PUSHES BACK INTO THE LOWER GREAT LAKES. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... FOR THE 12Z TAF CYCLE...EXPECT A MIX OF CONDITIONS EARLY THIS MORNING...MAINLY IN THE IFR CATEGORY. THIS WILL BE THE RESULT OF LOW LEVEL MOISTURE AND SHOWERS. A STEADY AREA OF RAIN EAST OF LAKE ONTARIO WILL LIFT NORTHWARD THIS MORNING...ALLOWING CONDITIONS AT ART TO IMPROVE. ELSEWHERE...SHOWERS WITH EMBEDDED THUNDERSTORMS SHOULD EXPAND RESULTING IN VARIABLE CONDITIONS...OCCASIONALLY IFR OR LESS IN HEAVIER RAINS. SHOWERS SHOULD BE VERY SLOW MOVING...LIKELY TO DRIFT NORTHEASTWARD THIS AFTERNOON BEFORE WEAKENING TONIGHT. ALTHOUGH SHOWERS SHOULD TAPER OFF LATER TONIGHT...SIGNIFICANT LOW MOISTURE...AND LESS MOISTURE ALOFT WILL LIKELY LEAD TO FAIRLY WIDESPREAD IFR OR LOWER CONDITIONS. ANY CLEARING ALOFT WOULD LIKELY RESULT IN SOME FAIRLY DENSE GROUND FOG. OUTLOOK... SATURDAY THROUGH TUESDAY...MAINLY VFR WITH A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WITH ASSOCIATED BRIEF MVFR/IFR. && .MARINE... LOW PRESSURE TRACKING ACROSS NEW YORK STATE WILL CAUSE NNE WINDS TO PICK UP THIS MORNING. CONDITIONS WILL BECOME A BIT CHOPPY...BUT WAVES ARE EXPECTED TO REMAIN BELOW SCA CRITERIA. AFTER THIS WINDS WILL DIMINISH...WITH NO HEADLINES ANTICIPATED FOR THIS WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FLOOD WATCH THROUGH THIS EVENING FOR NYZ006>008. FLOOD WATCH THROUGH THIS EVENING FOR NYZ001>005-010>014- 019>021-085. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...TJP/WOOD AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1040 AM EDT FRI JUN 28 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1040 AM FRIDAY... LITTLE DOUBT THAT MOST OF THE AREA WILL SEE SHOWERS/STORMS SOMETIME IN THE NEXT 18 HOURS... ALTHOUGH IT LOOKS LIKE WE MAY SEE A SLIGHT DELAY IN THE MORE ORGANIZED CONVECTION UNTIL LATER IN THE DAY. ACCORDING TO CURRENT MESOANALYSES WE ARE SLOWLY DESTABILIZING BUT WITH A LOT OF REMAINING CINH. LATEST SATELLITE IMAGERY SHOWS THAT MUCH OF THE MORNING STRATUS IN THE COASTAL PLAIN IS SLOWLY MOVING OUT TO THE EAST... WHILE THE WRN SECTIONS ARE SEEING HIGH THIN CLOUDS ASSOCIATED WITH THE NOW-DYING MCS DIVING FROM MEMPHIS INTO MS/AL. OVERNIGHT RUNS OF THE RAP MODEL HAVE HAD A DIFFICULT TIME WITH THE MCV TO OUR WEST... TRACKING IT EASTWARD THROUGH THE CAROLINAS WHEN TRAJECTORIES AND OBSERVATIONS SUGGEST THAT IT WILL TAKE A MORE SRN ROUTE THROUGH AL AND PERHAPS GA. WITH THIS FEATURE LIKELY SLIDING TO OUR SOUTH... WHILE ANOTHER AREA OF ENHANCED MID/HIGH-LEVEL FORCING FOR ASCENT TRACKS UP THROUGH PA... NC COULD BE LEFT BENEATH A RELATIVE MINIMUM IN TERMS OF LARGE SCALE DYNAMIC FORCING. THAT SAID... DEEP LAYER SHEAR IS EXPECTED TO STEADILY INCREASE THROUGH THE DAY -- ESPECIALLY INTO THE EVENING -- AND WITH THE DEARTH OF MORNING CLOUD COVER LEADING TO GOOD HEATING (TEMPS ARE RUNNING A FEW DEGREES COOLER THAN YESTERDAY IN THE SOUTHEAST BUT 1-7 DEGREES WARMER THAN THIS TIME THURSDAY OVER THE REST OF CENTRAL NC) AND MODELS PROJECTING 1500-2500 J/KG OF MLCAPE OVER ALL BUT THE NW CWA BY MID AFTERNOON... SEE NO REASON TO THINK THAT WE WON`T SEE INCREASING STORMS (IN NUMBER AND INTENSITY) HEADING THROUGH THE MID-LATE AFTERNOON AND THROUGH THE EVENING. THE LATEST HRRR RUN DEPICTS THIS SCENARIO QUITE WELL... BRINGING SCATTERED STORMS INTO THE TRIAD TOWARD 19-20Z THEN CONGEALING INTO AN ORGANIZED BAND OF STORM CLUSTERS HEADING EASTWARD THROUGH 04Z. STILL APPEARS THAT SEVERE WIND GUSTS WILL BE THE BIGGEST THREAT LATE TODAY INTO TONIGHT GIVEN THAT WE HAVE SOME DRY AIR NOT FAR OFF THE SURFACE. THE -10C TO -30C CAPE IS QUITE LOW THIS MORNING AND DON`T EXPECT THAT TO CHANGE MUCH WITH ONLY MINIMAL COOLING ALOFT AND NO APPARENT OPPORTUNITY FOR GOOD MOISTURE FLUX IN THIS MIXED PHASE REGION... THUS THE RISK OF LARGE HAIL SHOULD BE SECONDARY. IT IS INTERESTING HOW VERY DRY THE 12Z GSO SOUNDING WAS... WITH A PW OF 1.02 INCHES... MUCH LOWER THAN IN PAST DAYS AND A BIT OF AN OUTLIER COMPARED TO SURROUNDING UPPER AIR PLOTS. IT ALSO DEPARTS QUITE A BIT FROM THE PW NOTED ON TPW BLENDED IMAGERY (AROUND 1.4 INCHES IN THE TRIAD). MODELS DO SHOW A REMOISTENING OF THE COLUMN HERE THIS AFTERNOON... TOUGH TO BELIEVE CONSIDERING THE OBSERVED UPPER-AIR DATA UPSTREAM THIS MORNING AND THE LOW DEW POINTS IN THE TRIAD. WILL LEAVE IN GOOD CHANCE POPS HERE FOR NOW GIVEN THE IMPROVING BULK SHEAR THROUGH THE DAY... ALTHOUGH WE SHOULD SEE A RELATIVE MINIMUM IN COVERAGE IN THE TRIAD. LITTLE CHANGE IN HIGHS WITH TEMP TRENDS SUPPORTING READINGS OF 89-94. WILL CONTINUE TO TREND POPS DOWN AND OUT WEST TO EAST ESPECIALLY AFTER MIDNIGHT WITH LOSS OF HEATING. FOG/STRATUS HAS BEEN TOUGH TO FORECAST THE LAST FEW DAYS BUT WILL LEAN TOWARD PERSISTENCE... WITH BETTER COVERAGE EAST OF HIGHWAY 1 WITHIN A VERY LIGHT SW FLOW. -GIH && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM FRIDAY... AS THE UPPER TROUGH CONTINUES TO DEEPEN...MID TO UPPER LEVEL FLOW WILL BECOME SWLY AND WE WILL HAVE TO BE CONCERN WITH SHORTWAVE IMPULSES FROM THE SW AS OPPOSE TO THE W-NW FROM RECENT DAYS. ANOTHER IMPORTANT DIFFERENCE TO NOTE IS HOW MODELS ARE HANDLING THE MEANDERING SURFACE TROUGH/FRONT WITH BOTH THE NAM AND GFS ADVECTING CONSIDERABLY LOWER THETA-E AIR INTO THE LOW-LEVELS...WHICH EFFECTIVELY LESSENS CAPE OVER THE WESTERN PIEDMONT. THIS WOULD POTENTIALLY CONFINE THE BEST CONVECTIVE ACTIVITY TO EASTERN NC WITH LOWER PRECIP PROBABILITIES THAN CURRENTLY FORECASTING ACROSS THE WESTERN AND POSSIBLY CENTRAL PIEDMONT. FOR STORMS THAT DO DEVELOP...THE MODEST MID-LEVEL WIND FIELD OF 30 TO 35KTS AND STRONG DESTABILIZATION WITH 2000 TO 2500 J/KG OF MLCAPE WILL ONCE AGAIN SUPPORT THE THREAT FOR DAMAGING WING GUSTS AND HAIL. ADDITIONALLY WITH THE UPPER FLOW NOW PARALLEL TO THE WEAK SURFACE BOUNDARY...EASTERN AREAS WE WILL HAVE TO BE ON THE ALERT FOR FOR TRAINING OF STORMS AND THE INHERENT HEAVY RAIN AND FLOODING THREAT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 300 AM FRIDAY... AN UNUSUALLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST THROUGH MUCH OF THE PERIOD AS RIDGES DOMINATE WEST OF THE ROCKIES (EXTENDING UP INTO CANADA) AND ACROSS THE WESTERN ATLANTIC...WITH A DEEP TROUGH SANDWICHED IN THE MIDDLE. THIS TROUGH WILL GRADUALLY RETROGRADE THROUGH THE PERIOD...NEVERTHELESS LEAVING CENTRAL NC WITHIN A PERSISTENT DEEP SOUTHWESTERLY FLOW. AS A RESULT...NUMEROUS DISTURBANCES ALOFT WILL MOVE ACROSS THE AREA AND WITH MOISTURE REMAINING HIGH (BETWEEN 1.75-2 INCHES)...UNSETTLED WEATHER WILL CONTINUE THROUGH THE ENTIRE LONG TERM PERIOD (IF NOT LONGER)...WITH ABOVE NORMAL CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY (MOSTLY DIURNALLY DRIVEN). AS THE UPPER LEVEL TROUGH RETROGRADES...THE RIDGE OVER THE WESTERN ATLANTIC WILL PUSH WESTWARD...THEREFORE EVENTUALLY EXERTING SOME MORE INFLUENCE OVER THE REGION BY THE MIDDLE/LATTER PORTION OF THE WEEK. THIS IS WHEN WE MAY START SEEING A DECREASE IN PRECIP COVERAGE... ESPECIALLY OVER EASTERN NC. OTHERWISE...WITH THE INCREASED FLOW ALOFT...DECENT DEEP LAYER SHEAR WILL PERSIST OVER THE AREA AND THEREFORE WE SHOULD SEE MORE IN THE WAY OF ORGANIZED CONVECTION. THIS MAY RESULT IN SOME STRONG TO SEVERE STORMS. ANOTHER SIGNIFICANT WEATHER THREAT WILL BE THE INCREASING FLOODING RISK AS THE AREA REMAINS IN THIS EXTENDED WET PATTERN. DAYTIME HIGHS WILL GENERALLY BE BELOW NORMAL THROUGH THE PERIOD...WITH MOSTLY MID 80S EXPECTED. OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S. && .AVIATION /11Z THURSDAY THROUGH TUESDAY/... AS OF 640 AM FRIDAY... PATCHY IFR OT MVFR STRATUS AND OR FOG SHOULD LIFT BY 13-14Z THIS MORNING... WITH PREDOMINATELY VFR CONDITIONS INTO THE EARLY AFTERNOON BEFORE ANOTHER ROUND OF SCATTERED TO NUMEROUS STORMS ARE EXPECTED OVER CENTRAL NC. LOOKING BEYOND FRIDAY...THE WEATHER PATTERN WILL CHANGE VERY LITTLE THE NEXT SEVERAL DAYS. AN UNSEASONABLY STRONG LOW PRESSURE TROUGH COMBINED WITH A WARM AND UNSTABLE AIR WILL RESULT IN SCATTER TO NUMEROUS SHOWERS AND STORMS EACH AFTERNOON/EARLY EVENING... AND THE POTENTIAL FOR STRATUS OR FOG EACH MORNING. && .EQUIPMENT... KRAX WSR-88D WILL REMAIN DOWN OR IN DEGRADED MODE THROUGH THIS MORNING. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS WILL MAKE THESE REPAIRS AS QUICKLY AS POSSIBLE... AND IS WORKING TO RETURN THE RADAR TO NORMAL SERVICE BY EARLY THIS AFTERNOON. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...CBL LONG TERM...KRR AVIATION...CBL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
946 AM CDT FRI JUN 28 2013 .UPDATE... ISSUED AT 945 AM CDT FRI JUN 28 2013 THE MAIN CHANGES FOR THE MORNING UPDATE WILL BE TO INCREASE WINDS A BIT AND LOWER POPS SLIGHTLY THIS AFTERNOON. THERE WILL BE ABOUT 35KT TO MIX EFFICIENTLY BY AFTERNOON...AND WE WILL BE CLOSE TO WIND ADVISORY CRITERIA WITH GUSTS OVER 35MPH POSSIBLE. FOR NOW WILL HOLD ON AN ADVISORY...AND MONITOR POTENTIAL FOR 1PM UPDATE. WE WILL ALSO LOWER POPS A BIT THIS AFTERNOON WITH MORE ISOLATED (WEST) TO SCATTERED (EAST) COVERAGE OF SHOWERS AND A FEW STORMS EXPECTED. CAPES RISE AROUND 1000 J/KG BY AFTERNOON WITH CYCLONIC FLOW AND A JET STREAK. TEMPS MAY ALSO BE SLIGHTLY COOLER IN ALL BUT THE FAR WEST AND WILL LOWER A FEW DEGREES WITH CLOUDS EAST AND LOWER CONVECTIVE TEMPS TODAY. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 CHALLENGES INCLUDE CLOUD COVER/PRECIPITATION CHANCES TODAY AND THEN TEMPERATURES THROUGH THE PERIOD. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT...BUT WILL LEAN ON LATEST RAP GUIDANCE FOR NEAR TERM FORECAST. FOR TODAY...STRATOCUMULUS DECK ACROSS NORTH-CENTRAL MN WILL EXPAND SOUTH AND WEST THROUGH THE DAY GIVEN CONVECTIVE TEMPERATURES IN THE UPPER 60S TO MID 70S. WITH A 100 KT 300 HPA JET STREAK MOVING THROUGH NORTHWEST FLOW ALOFT AND 500 TO 1000 J/KG OF MLCAPE... SOME OF THESE THERMAL CU MAY GIVE WAY TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS. REMOVED POPS ALONG AND WEST OF THE VALLEY THIS MORNING WITH A MOSTLY SUNNY START TO THE DAY...BUT WILL EXPAND CHANCE POPS SOUTH AND WEST WITH INCREASING CLOUD COVER THIS AFTERNOON. BOUNDARY LAYER IS 3 TO 6 C COLDER THAN YESTERDAY... SO EXPECT DAYTIME HIGHS IN THE 70S. WITH 20 TO 30 KTS AT 850 HPA TO MIX TO THE SURFACE...EXPECT ANOTHER BREEZY AFTERNOON WITH WINDS FROM 15 TO 20 MPH AND OCCASIONAL GUSTS UP TO 30 MPH. THERMAL CU WILL DISSIPATE AFTER SUNSET...BUT EXPECT SOME THICKER CLOUD COVER TO TAKE ITS TIME MOVING OUT OF THE REGION OVERNIGHT. WINDS WILL SUBSIDE WITH SURFACE HIGH PRESSURE BUILDING ACROSS THE REGION. OVERNIGHT LOWS WILL BE IN THE 50S. MOST OF SATURDAY WILL BE DRY...BUT DID KEEP 20 POPS REGION-WIDE THROUGH THE DAY AS OPERATIONAL MODELS PAINT SEEMINGLY RANDOM LIGHT QPF IN ASSOCIATION WITH A WEAK SHORT-WAVE ALOFT. SURFACE TO MID- LEVEL FORCING IS WEAK...SO EXPECT MINIMAL ACCUMULATION WITH ANY SHOWERS THAT DO DEVELOP. ANOTHER COOLER DAY WITH HIGHS AGAIN IN THE 70S. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 SURFACE PRESSURE RIDGE WILL SLIDE SLOWLY ACROSS THE NORTHERN PLAINS SUNDAY AND MONDAY RESULTING IN DRY...MOSTLY SUNNY CONDITIONS. WINDS WILL BE LIGHT AND TEMPERATURES WILL BE NEAR SEASONAL NORMALS WITH HIGHS IN THE UPPER 70S TO LOWER 80S. A BLEND OF THE GFS/ECMWF TO BE FOLLOWED EARLY IN THE EXTENDED THEN TRENDING TOWARD THE GFS IN DAYS 5-7. THE UPPER PATTERN AMPLIFIES DURING THE PERIOD WITH RIDGING OVER THE WRN CONUS AND TROF OVER THE ERN THIRD OF THE COUNTRY. THE RIDGING OUT WEST WILL RETROGRADE SOMEWHAT WEST ALLOWING FOR PIECES OF S/WV ENERGY TO SLIDE DOWN THE BACK SIDE OF THE TROF BY TUE/TUE NIGHT. A FRONTAL BOUNDARY ACROSS THE REGION WILL HELP FOCUS PRECIPITATION TUE-THU WITH WED BEING THE MOST OPTIMAL PERIOD FOR SCATTERED SHRA/TSRA. THE BOUNDARY IS EXPECTED TO WEAKEN BY THU. TEMPERATURES WILL BE TEMPERED WITH HIGHS IN THE UPPER 70S TO AROUND 80 THROUGH THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 704 AM CDT FRI JUN 28 2013 WESTERN EDGE OF MVFR/IFR CLOUD DECK EXTENDS ALONG A KHCO-KMAH- KPKD LINE AND WILL CONTINUE TO SLIDE SOUTH AND WEST AROUND 10 KTS. CEILINGS SHOULD LIFT TO VFR CONDITIONS BY THIS AFTERNOON. CLEAR SKIES AT KGFK/KFAR/KDVL THIS MORNING WILL FILL-IN WITH THERMAL CU THROUGHOUT THE DAY. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE MAINLY ALONG AND EAST OF THE VALLEY...BUT TIMING AND COVERAGE UNCERTAINTY PRECLUDES MENTION IN 12 UTC TAFS. NORTHWEST WIND WILL BECOME BREEZY THIS AFTERNOON...WITH OCCASIONAL GUSTS FROM 25 TO 30 KTS. && .HYDROLOGY... ISSUED AT 930 PM CDT THU JUN 27 2013 RUNOFF CONTINUES TO MAKE ITS WAY INTO THE RED RIVER FROM AREA TRIBUTARIES. TRENDS CONTINUE TO BE ON TARGET FROM THE MORNING FORECAST UPDATE FOR THE RIVER POINTS. THE RED RIVER AT FARGO IS STILL FORECAST TO CREST NEAR MAJOR FLOOD STAGE TOWARDS LATE TODAY OR TONIGHT. OTHERWISE...RISES ARE EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS ON CENTRAL AND NORTHERN SECTIONS OF THE RED...WITH A FEW FORECAST POINTS EXPECTED TO RISE ABOVE MINOR FLOOD STAGE. WAHPETON REMAINS BELOW FLOOD STAGE AND IS ANTICIPATED TO CONTINUE FALLING. HOWEVER...EXPECTED RELEASES FROM WHITE ROCK DAM MAY SLOW THE RECESSION OF RIVER LEVELS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...DK SHORT TERM...ROGERS LONG TERM...ROGERS/FRAZIER AVIATION...ROGERS HYDROLOGY...HOPKINS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
704 AM CDT FRI JUN 28 2013 .UPDATE... ISSUED AT 704 AM CDT FRI JUN 28 2013 WESTERN EDGE OF STRATOCUMULUS DECK NOW EXTENDS FROM HALLOCK TO MAHNOMEN TO PARK RAPIDS AND IS SLOWLY EXPANDING TO THE SOUTH AND WEST AROUND 10 KTS. WITH SUNRISE...EXPECT THERMAL CU TO DEVELOP THROUGH THE DAY...RESULTING IN PARTLY TO MOSTLY CLOUDY SKIES BY THIS AFTERNOON. ADJUSTED SKY/POP GRIDS TO REFLECT LATEST OBSERVATIONS. OTHERWISE...FORECAST IS ON TRACK WITH NO MAJOR CHANGES NEEDED AT THIS TIME. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 CHALLENGES INCLUDE CLOUD COVER/PRECIPITATION CHANCES TODAY AND THEN TEMPERATURES THROUGH THE PERIOD. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT...BUT WILL LEAN ON LATEST RAP GUIDANCE FOR NEAR TERM FORECAST. FOR TODAY...STRATOCUMULUS DECK ACROSS NORTH-CENTRAL MN WILL EXPAND SOUTH AND WEST THROUGH THE DAY GIVEN CONVECTIVE TEMPERATURES IN THE UPPER 60S TO MID 70S. WITH A 100 KT 300 HPA JET STREAK MOVING THROUGH NORTHWEST FLOW ALOFT AND 500 TO 1000 J/KG OF MLCAPE... SOME OF THESE THERMAL CU MAY GIVE WAY TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS. REMOVED POPS ALONG AND WEST OF THE VALLEY THIS MORNING WITH A MOSTLY SUNNY START TO THE DAY...BUT WILL EXPAND CHANCE POPS SOUTH AND WEST WITH INCREASING CLOUD COVER THIS AFTERNOON. BOUNDARY LAYER IS 3 TO 6 C COLDER THAN YESTERDAY... SO EXPECT DAYTIME HIGHS IN THE 70S. WITH 20 TO 30 KTS AT 850 HPA TO MIX TO THE SURFACE...EXPECT ANOTHER BREEZY AFTERNOON WITH WINDS FROM 15 TO 20 MPH AND OCCASIONAL GUSTS UP TO 30 MPH. THERMAL CU WILL DISSIPATE AFTER SUNSET...BUT EXPECT SOME THICKER CLOUD COVER TO TAKE ITS TIME MOVING OUT OF THE REGION OVERNIGHT. WINDS WILL SUBSIDE WITH SURFACE HIGH PRESSURE BUILDING ACROSS THE REGION. OVERNIGHT LOWS WILL BE IN THE 50S. MOST OF SATURDAY WILL BE DRY...BUT DID KEEP 20 POPS REGION-WIDE THROUGH THE DAY AS OPERATIONAL MODELS PAINT SEEMINGLY RANDOM LIGHT QPF IN ASSOCIATION WITH A WEAK SHORT-WAVE ALOFT. SURFACE TO MID- LEVEL FORCING IS WEAK...SO EXPECT MINIMAL ACCUMULATION WITH ANY SHOWERS THAT DO DEVELOP. ANOTHER COOLER DAY WITH HIGHS AGAIN IN THE 70S. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 SURFACE PRESSURE RIDGE WILL SLIDE SLOWLY ACROSS THE NORTHERN PLAINS SUNDAY AND MONDAY RESULTING IN DRY...MOSTLY SUNNY CONDITIONS. WINDS WILL BE LIGHT AND TEMPERATURES WILL BE NEAR SEASONAL NORMALS WITH HIGHS IN THE UPPER 70S TO LOWER 80S. A BLEND OF THE GFS/ECMWF TO BE FOLLOWED EARLY IN THE EXTENDED THEN TRENDING TOWARD THE GFS IN DAYS 5-7. THE UPPER PATTERN AMPLIFIES DURING THE PERIOD WITH RIDGING OVER THE WRN CONUS AND TROF OVER THE ERN THIRD OF THE COUNTRY. THE RIDGING OUT WEST WILL RETROGRADE SOMEWHAT WEST ALLOWING FOR PIECES OF S/WV ENERGY TO SLIDE DOWN THE BACK SIDE OF THE TROF BY TUE/TUE NIGHT. A FRONTAL BOUNDARY ACROSS THE REGION WILL HELP FOCUS PRECIPITATION TUE-THU WITH WED BEING THE MOST OPTIMAL PERIOD FOR SCATTERED SHRA/TSRA. THE BOUNDARY IS EXPECTED TO WEAKEN BY THU. TEMPERATURES WILL BE TEMPERED WITH HIGHS IN THE UPPER 70S TO AROUND 80 THROUGH THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 704 AM CDT FRI JUN 28 2013 WESTERN EDGE OF MVFR/IFR CLOUD DECK EXTENDS ALONG A KHCO-KMAH0- KPKD LINE AND WILL CONTINUE TO SLIDE SOUTH AND WEST AROUND 10 KTS. CEILINGS SHOULD LIFT TO VFR CONDITIONS BY THIS AFTERNOON. CLEAR SKIES AT KGFK/KFAR/KDVL THIS MORNING WILL FILL-IN WITH THERMAL CU THROUGHOUT THE DAY. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE MAINLY ALONG AND EAST OF THE VALLEY...BUT TIMING AND COVERAGE UNCERTAINTY PRECLUDES MENTION IN 12 UTC TAFS. NORTHWEST WIND WILL BECOME BREEZY THIS AFTERNOON...WITH OCCASIONAL GUSTS FROM 25 TO 30 KTS. && .HYDROLOGY... ISSUED AT 930 PM CDT THU JUN 27 2013 RUNOFF CONTINUES TO MAKE ITS WAY INTO THE RED RIVER FROM AREA TRIBUTARIES. TRENDS CONTINUE TO BE ON TARGET FROM THE MORNING FORECAST UPDATE FOR THE RIVER POINTS. THE RED RIVER AT FARGO IS STILL FORECAST TO CREST NEAR MAJOR FLOOD STAGE TOWARDS LATE TODAY OR TONIGHT. OTHERWISE...RISES ARE EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS ON CENTRAL AND NORTHERN SECTIONS OF THE RED...WITH A FEW FORECAST POINTS EXPECTED TO RISE ABOVE MINOR FLOOD STAGE. WAHPETON REMAINS BELOW FLOOD STAGE AND IS ANTICIPATED TO CONTINUE FALLING. HOWEVER...EXPECTED RELEASES FROM WHITE ROCK DAM MAY SLOW THE RECESSION OF RIVER LEVELS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...ROGERS SHORT TERM...ROGERS LONG TERM...ROGERS/FRAZIER AVIATION...ROGERS HYDROLOGY...HOPKINS
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1032 AM CDT FRI JUN 28 2013 .UPDATE... MORNING FORECAST UPDATE. && .DISCUSSION... STRONG UPPER LEVEL RIDGE REALLY HOLDING OVER THE 4 CORNERS/GREAT BASIN REGION THIS MORNING. UPPER LEVEL FLOW MORE NORTHERLY TODAY AS EXPECTED WITH UPPER LOW TAKING SHAPE OVER THE GREAT LAKES. SFC FRONT LOOKS TO BE PUSHING INTO THE RED RIVER REGION. MORNING 850MB ANALYSIS HAS TEMPS A TOUCH LOWER THAN EXPECTED FROM YESTERDAY`S FORECAST. THERMAL RIDGE STILL SHOULD SLIDE OVER THE ARE LATER THIS AFTERNOON WAS 850MB WINDS TURN MORE NORTHERLY. SFC WINDS SHOULD CONTINUE FROM SW/W AND PERHAPS TURN NW LATER THIS AFTERNOON. THINK INLAND AREAS SHOULD REACH 98-102F RANGE. TEMPS AT GLS WILL BE TRICKY AS CURRENT WIND FROM W WHICH COULD HELP LEAD TO ADDITIONAL HEATING. OVERALL THINK FORECAST IS ON TRACK WITH CURRENT OBS AND TRENDS. WILL NOT DO AN UPDATE AT THIS TIME. 39 && .PREV DISCUSSION... /ISSUED 616 AM CDT FRI JUN 28 2013/ DISCUSSION... SEE AVIATION FOR 12Z TAF ISSUANCE. AVIATION... IFR AND MVFR STRATUS DECK HAS MADE ITS WAY INTO PARTS OF SOUTHEAST TEXAS THIS MORNING. STRATUS DECK SHOULD STAY CONFINED TO KCLL...KUTS...AND KCXO TERMINALS THIS MORNING AND BE DISSIPATED BY 10AM. ISSUE FOR TODAY WILL BE A BOUNDARY POSSIBLY MAKING ITS WAY DOWN INTO THE NORTHERN TERMINALS DURING THE AFTERNOON. THERE IS A A VERY SLIGHT CHANCE OF A STRAY SHOWER OR THUNDERSTORM AT THE FAR NORTHERN TERMINALS OF KCLL AND KUTS. WINDS SHOULD BE OUT OF THE WSW UNTIL THE AFTERNOON WHEN THE SEA BREEZE MOVES INLAND. AFTER THE SEA BREEZE PUSHES INLAND WINDS SHOULD SWITCH TOWARDS A MORE SOUTHERLY COMPONENT. VFR CONDITIONS WILL PREVAIL THROUGH TODAY AFTER MORNING STRATUS BURNS OFF. 23 PREV DISCUSSION... /ISSUED 433 AM CDT FRI JUN 28 2013/ DISCUSSION... A STRONG UPPER LEVEL RIDGE OF HIGH PRESSURE IS CENTERED OVER SOUTHERN UTAH WITH THE RIDGE EASTWARD INTO EAST TEXAS. 850 MB TEMPS CONTINUE TO WARM WITH KCRP NOW UP TO 22 C AND KLCH NOW UP TO 20 C. 700 MB TEMPS ALSO CONTINUE TO WARM AND ARE NOW UP TO 13 C. MAX TEMPS TODAY WILL PROBABLY BE 2-3 DEGREES WARMER THAN YESTERDAY. NAM 12 STILL HINTING THAT A SEA BREEZE CIRCULATION WILL DEVELOP AND FEEL THIS WILL HINDER THE TEMPERATURE RISE AT COASTAL SITES TODAY. THERE WILL BE MORE OF AN OFFSHORE FLOW ON SATURDAY AND FEEL COASTAL SITES COULD GET PLENTY WARM AT THAT TIME. A WEAK BOUNDARY WILL APPROACH THE EXTREME NORTH PART OF SE TX THIS EVENING AND STALL. THE 4 KM WRF...THE RAP AND 06Z NAM 12 ARE NOW DEVELOPING SOME PCPN ALONG THE BOUNDARY. WILL SOMEWHAT RELUCTANTLY ADD 20 POPS OVER THE EXTREME NORTH FROM 00-06Z. THE BOUNDARY WILL CROSS SE TX ON SATURDAY WITH 500 HEIGHTS SLOWLY DROPPING. FEEL A WARM START AND DRIER AIR ADVECTING INTO THE REGION WILL COMPENSATE FOR THE LOWER HEIGHTS SO WILL MAINTAIN VERY WARM TEMPS FOR SAT AFTN. A S/WV WILL MOVE SE ON THE PERIPHERY OF THE UPPER RIDGE LATE SAT NIGHT INTO SUNDAY. THE TEXAS TECH WRF SHOWS A SWATH OF PCPN DEVELOPING IN THE NW FLOW AND MOVING INTO THE AREA BETWEEN 06-12Z SUNDAY. ADDED 20 POPS FOR THIS POTENTIAL ON SAT NIGHT. DRIER LOW LEVEL AIR WILL ALLOW MIN TEMPS TO TREND SLIGHTLY COOLER SUNDAY MORNING AND LOWER HEIGHTS WILL PORTEND COOLER MAX TEMPS ON SUNDAY AFTN. THE UPPER RIDGE RETREATS WEST ON SUNDAY AND BEYOND AS AN UPPER LEVEL TROUGH OVER THE EASTERN U.S. RETROGRADES WEST. HEIGHTS WILL LOWER OVER SE TX WITH A SUBTLE DECREASE IN AFTERNOON TEMPS EXPECTED. THE AIR MASS WILL BE RATHER DRY SO AM STILL EXPECTING MAX TEMPS TO WARM INTO THE MIDDLE 90S. MOISTURE LEVELS BEGIN TO DEEPEN ON WEDNESDAY SO AM EXPECTING AN INCREASE IN CLOUD COVER AND HIGHER RAIN CHANCES. THE UPPER LEVEL TROUGH WILL LINGER ACROSS THE CENTRAL PLAINS THROUGH THE END OF NEXT WEEK. WILL CARRY RAIN CHANCES...ADDITIONAL CLOUD COVER AND COOLER TEMPS IN RESPONSE TO THE UPPER TROUGH. 43 MARINE... LIGHT TO MODERATE WIND SPEEDS WILL REMAIN THROUGH THE AFTERNOON. WINDS SHOULD THEN BECOME MODERATE AND APPROACH SCEC CRITERIA LATE FRIDAY INTO EARLY SATURDAY AS THE THERMAL GRADIENT INCREASES ALONG WITH THE BOUNDARY MOVING SOUTHWARDS. THE BOUNDARY SHOULD THEN STALL OUT NEAR THE COAST ON SATURDAY THEN HAVE THE WINDS BRIEFLY SWITCH TO THE NORTH AS A SECONDARY BOUNDARY MARCHES SOUTHWARD. THE BOUNDARY SHOULD THEN WASH OUT AND PULL NORTHWARDS EARLY WEDNESDAY GIVING WAY TO ONSHORE WINDS. 23 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 102 75 102 72 96 / 0 20 10 20 20 HOUSTON (IAH) 100 76 100 75 97 / 0 10 10 20 20 GALVESTON (GLS) 94 80 97 78 96 / 10 10 10 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
616 AM CDT FRI JUN 28 2013 .DISCUSSION... SEE AVIATION FOR 12Z TAF ISSUANCE. && .AVIATION... IFR AND MVFR STRATUS DECK HAS MADE ITS WAY INTO PARTS OF SOUTHEAST TEXAS THIS MORNING. STRATUS DECK SHOULD STAY CONFINED TO KCLL...KUTS...AND KCXO TERMINALS THIS MORNING AND BE DISSIPATED BY 10AM. ISSUE FOR TODAY WILL BE A BOUNDARY POSSIBLY MAKING ITS WAY DOWN INTO THE NORTHERN TERMINALS DURING THE AFTERNOON. THERE IS A A VERY SLIGHT CHANCE OF A STRAY SHOWER OR THUNDERSTORM AT THE FAR NORTHERN TERMINALS OF KCLL AND KUTS. WINDS SHOULD BE OUT OF THE WSW UNTIL THE AFTERNOON WHEN THE SEA BREEZE MOVES INLAND. AFTER THE SEA BREEZE PUSHES INLAND WINDS SHOULD SWITCH TOWARDS A MORE SOUTHERLY COMPONENT. VFR CONDITIONS WILL PREVAIL THROUGH TODAY AFTER MORNING STRATUS BURNS OFF. 23 && .PREV DISCUSSION... /ISSUED 433 AM CDT FRI JUN 28 2013/ DISCUSSION... A STRONG UPPER LEVEL RIDGE OF HIGH PRESSURE IS CENTERED OVER SOUTHERN UTAH WITH THE RIDGE EASTWARD INTO EAST TEXAS. 850 MB TEMPS CONTINUE TO WARM WITH KCRP NOW UP TO 22 C AND KLCH NOW UP TO 20 C. 700 MB TEMPS ALSO CONTINUE TO WARM AND ARE NOW UP TO 13 C. MAX TEMPS TODAY WILL PROBABLY BE 2-3 DEGREES WARMER THAN YESTERDAY. NAM 12 STILL HINTING THAT A SEA BREEZE CIRCULATION WILL DEVELOP AND FEEL THIS WILL HINDER THE TEMPERATURE RISE AT COASTAL SITES TODAY. THERE WILL BE MORE OF AN OFFSHORE FLOW ON SATURDAY AND FEEL COASTAL SITES COULD GET PLENTY WARM AT THAT TIME. A WEAK BOUNDARY WILL APPROACH THE EXTREME NORTH PART OF SE TX THIS EVENING AND STALL. THE 4 KM WRF...THE RAP AND 06Z NAM 12 ARE NOW DEVELOPING SOME PCPN ALONG THE BOUNDARY. WILL SOMEWHAT RELUCTANTLY ADD 20 POPS OVER THE EXTREME NORTH FROM 00-06Z. THE BOUNDARY WILL CROSS SE TX ON SATURDAY WITH 500 HEIGHTS SLOWLY DROPPING. FEEL A WARM START AND DRIER AIR ADVECTING INTO THE REGION WILL COMPENSATE FOR THE LOWER HEIGHTS SO WILL MAINTAIN VERY WARM TEMPS FOR SAT AFTN. A S/WV WILL MOVE SE ON THE PERIPHERY OF THE UPPER RIDGE LATE SAT NIGHT INTO SUNDAY. THE TEXAS TECH WRF SHOWS A SWATH OF PCPN DEVELOPING IN THE NW FLOW AND MOVING INTO THE AREA BETWEEN 06-12Z SUNDAY. ADDED 20 POPS FOR THIS POTENTIAL ON SAT NIGHT. DRIER LOW LEVEL AIR WILL ALLOW MIN TEMPS TO TREND SLIGHTLY COOLER SUNDAY MORNING AND LOWER HEIGHTS WILL PORTEND COOLER MAX TEMPS ON SUNDAY AFTN. THE UPPER RIDGE RETREATS WEST ON SUNDAY AND BEYOND AS AN UPPER LEVEL TROUGH OVER THE EASTERN U.S. RETROGRADES WEST. HEIGHTS WILL LOWER OVER SE TX WITH A SUBTLE DECREASE IN AFTERNOON TEMPS EXPECTED. THE AIR MASS WILL BE RATHER DRY SO AM STILL EXPECTING MAX TEMPS TO WARM INTO THE MIDDLE 90S. MOISTURE LEVELS BEGIN TO DEEPEN ON WEDNESDAY SO AM EXPECTING AN INCREASE IN CLOUD COVER AND HIGHER RAIN CHANCES. THE UPPER LEVEL TROUGH WILL LINGER ACROSS THE CENTRAL PLAINS THROUGH THE END OF NEXT WEEK. WILL CARRY RAIN CHANCES...ADDITIONAL CLOUD COVER AND COOLER TEMPS IN RESPONSE TO THE UPPER TROUGH. 43 MARINE... LIGHT TO MODERATE WIND SPEEDS WILL REMAIN THROUGH THE AFTERNOON. WINDS SHOULD THEN BECOME MODERATE AND APPROACH SCEC CRITERIA LATE FRIDAY INTO EARLY SATURDAY AS THE THERMAL GRADIENT INCREASES ALONG WITH THE BOUNDARY MOVING SOUTHWARDS. THE BOUNDARY SHOULD THEN STALL OUT NEAR THE COAST ON SATURDAY THEN HAVE THE WINDS BRIEFLY SWITCH TO THE NORTH AS A SECONDARY BOUNDARY MARCHES SOUTHWARD. THE BOUNDARY SHOULD THEN WASH OUT AND PULL NORTHWARDS EARLY WEDNESDAY GIVING WAY TO ONSHORE WINDS. 23 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 102 75 102 72 96 / 0 20 10 20 20 HOUSTON (IAH) 100 76 100 75 97 / 0 10 10 20 20 GALVESTON (GLS) 94 80 97 78 96 / 10 10 10 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43 AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS TUCSON AZ
205 PM MST FRI JUN 28 2013 .SYNOPSIS...EXPECT VERY HOT DAYTIME TEMPERATURES THROUGH SUNDAY. THERE IS ALSO A SLIGHT CHANCE OF MAINLY MOUNTAIN THUNDERSTORMS EAST OF TUCSON SATURDAY. GRADUALLY INCREASING MOISTURE WILL THEN LEAD TO THE DAILY CYCLE OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS DURING THE UPCOMING WEEK. THE INCREASED MOISTURE WILL ALSO PROVIDE A GRADUAL MODERATION IN DAYTIME TEMPERATURES NEXT WEEK. && .DISCUSSION...599 DM HIGH PRESSURE CENTERED NEAR THE FOUR CORNERS PROVIDING A GENERALLY LIGHT ELY FLOW REGIME ACROSS SE AZ THIS AFTERNOON. 28/17Z RUC HRRR DEPICTED TWO CLUSTERS OF SHOWERS/TSTMS TO MOVE WWD ACROSS THE WHITE MOUNTAINS INTO NRN GRAHAM COUNTY NORTH OF SAFFORD LATE THIS AFTERNOON AND EARLY THIS EVENING. THUS...HAVE CONFINED A SLIGHT CHANCE OF SHOWERS/TSTMS TO THE WHITE MOUNTAINS AND NRN GRAHAM COUNTY THIS EVENING. POPS WERE REDUCED TO LESS THAN 10 PERCENT ELSEWHERE. DRY CONDITIONS TO OCCUR AREA-WIDE LATE TONIGHT AND SAT MORNING. SLIGHTLY GREATER COVERAGE OF SHOWERS/ TSTMS TO OCCUR SAT AFTERNOON AND SAT EVENING AS THE UPPER HIGH REMAINS QUASI-STATIONARY NEAR THE FOUR CORNERS REGION. 28/12Z GFS/ECMWF WERE SIMILAR WITH DEPICTING A GRADUAL INCREASE OF MOISTURE STARTING SUN AND CONTINUING DURING THE UPCOMING WEEK. ELY MID-LEVEL STEERING FLOW SHOULD INCREASE SUFFICIENTLY TO JUSTIFY A SLIGHT CHANCE OF SHOWERS/TSTMS AS FAR WEST AS THE TUCSON METRO AREA SUN AFTERNOON AND SUN EVENING. CHANCE-CATEGORY POPS TO OCCUR SUN AFTERNOON AND SUN EVENING ACROSS THE MOUNTAINS OF GREENLEE/GRAHAM/ COCHISE COUNTIES. EXPECT A SIMILAR POP SCENARIO MON AFTERNOON AND MON EVENING. THEREAFTER...POPS WERE TRENDED UPWARD BY WED AS THE GFS/ECMWF CONTINUED TO DEPICT GRADUALLY INCREASING MOISTURE ACROSS THE AREA. HAVE OPTED FOR THE HIGHEST POPS TO OCCUR WED...WITH CHANCE-CATEGORY POPS FROM TUCSON EWD/SWD AND ONLY SINGLE DIGIT POPS ACROSS WRN PIMA COUNTY. MID-LEVEL STEERING FLOW IS THEN PROGGED TO BECOME MORE NORTHERLY BY LATE NEXT WEEK AS THE WRN CONUS HIGH SHIFTS INTO SRN CALIFORNIA. HAVE REDUCED POPS SLIGHTLY THUR-FRI. HOWEVER...EXPECT AT LEAST A SLIGHT CHANCE OF SHOWERS/TSTMS FROM TUCSON EWD/SWD TO CONTINUE THUR-FRI DURING THE AFTERNOON AND EVENING HOURS. AS FOR TEMPS...HAVE MAINTAINED THE EXCESSIVE HEAT WARNING THRU 9 PM MST SUN. CONFIDENCE IS SOMEWHAT LOW THAT WARNING CRITERIA WILL BE WIDESPREAD SUN AFTERNOON. THUS...FOR CONTINUITY...HAVE KEPT THE EXCESSIVE HEAT WARNING FOR SUN. THEREAFTER...EXPECT A VERY GRADUAL MODERATION IN DAYTIME TEMPS MON-FRI. && .AVIATION...ISOLD -TSRA MAINLY NEAR MTNS EAST OF KTUS THRU THIS EVENING AND AGAIN SATURDAY AFTERNOON. OTHERWISE...SCT-BKN CLOUDS MOSTLY ABOVE 12K FT AGL THRU SATURDAY AFTERNOON OR 30/00Z. SURFACE WIND TONIGHT AND SATURDAY MORNING MOSTLY ELY/SELY 10-15 KTS WITH GUSTS TO 20 KTS. SURFACE WIND SATURDAY AFTERNOON VARIABLE IN DIRECTION AT LESS THAN 10 KTS. TEMPERATURES OF 100 DEGREES OR HIGHER WILL PRODUCE INCREASED TAKE OFF LENGTHS DURING PEAK HEATING THIS WEEKEND. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...THERE IS A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS ACROSS THE HIGHER TERRAIN EAST OF TUCSON THIS WEEKEND. THEREAFTER...GRADUALLY INCREASING MOISTURE WILL THEN PRODUCE THE DAILY CYCLE OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS NEXT WEEK. OTHERWISE...VERY HOT TEMPERATURES WILL CONTINUE THIS WEEKEND. THE INCREASING MOISTURE WILL LEAD TO A GRADUAL DECREASE IN DAYTIME TEMPERATURES DURING THE UPCOMING WEEK. GUSTY WINDS WILL PREVAIL DURING THE AFTERNOON HOURS DUE TO STRONG DAYTIME HEATING. && .TWC WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 9 PM MST SUNDAY FOR AZZ501>506-509- 515. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON BF
AREA FORECAST DISCUSSION
NWS PUEBLO CO
315 PM MDT FRI JUN 28 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 256 PM MDT FRI JUN 28 2013 ...MORE STORMS FOR THE PLAINS LATER TODAY... THE TWO MAIN CONCERNS THIS AFTERNOON/TONIGHT AND TOMORROW ARE THE CHANCES OF SEVERE THUNDERSTORMS ACROSS THE I-25 CORRIDOR AND EASTERN PLAINS...AND HEAVY PRECIPITATION IN AND AROUND BURN AREAS. CURRENTLY...A SMALL CIRCULATION 20 TO 30 MILES NNW OF COS...WITH ASSOCIATED QUASISTATIONARY BOUNDARY...IS HELPING TO ENHANCE THUNDERSTORM DEVELOPMENT ALONG THE HIGHER TERRAIN. ESPECIALLY IN TELLER COUNTY WHERE NUMEROUS CG STRIKES HAVE BEEN DETECTED WITH A STRONG CELL CURRENTLY MOVING SOUTHWARD TOWARDS CANON CITY. THE 12Z GFS40 PV15 ALSO SHOWS A WEAK MIDLEVEL DISTURBANCE COMING THROUGH THE NORTHWEST FLOW AROUND 00Z TONIGHT. THESE INGREDIENTS...ALONG WITH DEWPOINTS IN THE 30`S AND 40`S ALONG THE I-25 CORRIDOR...WILL AID IN KEEPING THUNDERSTORMS GOING AFTER SUNSET. SOME OF THESE STORMS COULD BRIEFLY BECOME SEVERE...MINALY DUE TO GUSTY OUTFLOW WINDS. LATER TONIGHT...THE HRRR/RAP/NAM12 CONTINUE TO INDICATE THUNDERSTORMS WILL MOVE SOUTHEAST ACROSS THE PLAINS THROUGH 06Z. THE MODELS...ESPECIALLY THE HRRR AND RAP...SEEM A BIT OVERDONE ON THE MOISTURE (CURRENT TD IN LHX IS 26)...BUT STILL FEEL ISOLATED THUNDERSTORMS WILL BE POSSIBLE ACROSS THE PLAINS TONIGHT. THE PRIMARY THREAT FROM THESE STORMS WILL LIKELY BE WIND...BUT IF MOISTURE DOES RETURN VIA A NORTHEASTERLY SURGE AS THE RAP AND HRRR FORECAST...SOME SMALL HAIL IS POSSIBLE AS 0-6KM BULK SHEAR IS 30-40KTS ACROSS THE PLAINS. THE NAM12/GFS/EC ALL SHOW ANOTHER...MORE SIGNIFICANT...DISTURBANCE IN THE NORTHWEST FLOW PUSHING THROUGH THE AREA SATURDAY MORNING. THIS DISTURBANCE WILL DROP A COLD FRONT THROUGH THE AREA AROUND 12Z SATURDAY. THIS WILL CREATE GUSTY NORTHEASTERLY WINDS AND HELP DROP 700MB TEMPERATURES TO AROUND 11C...LEADING TO COOLER MAX TEMPERATURES AND INCREASED MOSITURE ACROSS THE FORECAST AREA. THUNDERSTORMS ARE LIKELY ONCE AGAIN ACROSS THE MOUNTAINS DURING THE LATE MORNING AND AFTERNOON. CURRENT ACTIVE BURN AREAS SUCH AS THE WEST FORK COMPLEX AND EAST PEAK FIRES...ALONG WITH THE WALDO CANYON SCAR...WILL NEED TO MONITORED FOR FLOODING POTENTIAL TOMORROW AFTERNOON. THE POTENTIAL WILL EXIST ONCE AGAIN FOR ISOLATED SEVERE STORMS ACROSS THE EASTERN PLAINS DUE TO THE INCREASE IS MOISTURE. -PJC .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 256 PM MDT FRI JUN 28 2013 ...COOLER TEMPERATURES WITH CONTINUED CHANCES OF RAIN...AND FLASH FLOODING CONCERNS FOR THE BURN SCARS... AN ACTIVE PERIOD IS EXPECTED AS THE UPPER LEVEL RIDGE AXIS SHIFTS WEST AND REMAINS CENTERED THROUGH THE GREAT BASIN. NORTHERLY FLOW ALOFT IS EXPECTED ACROSS COLORADO THROUGH AT LEAST TUESDAY. AT THE SURFACE...EXPECT EAST TO SOUTHEAST UPSLOPE SURFACE FLOW TO CONTINUE WITH DEWPOINTS IN THE 50S ACROSS THE PLAINS SUNDAY. MODELS SHOW A WEAK DISTURBANCE MOVING THROUGH THE FLOW ALOFT SUNDAY AND CURRENT MODEL TIMING SHOWS IT MOVING THROUGH SOUTHEAST COLORADO DURING PEAK HEATING. WITH COOLER AIRMASS IN PLACE...CAPES IN THE 1000-1500J/KG RANGE ALONG THE SOUTHEAST COLORADO MOUNTAINS... EXPECT TO HAVE ANOTHER DAY OF CONVECTION FIRING BY EARLY AFTERNOON OVER THE HIGHER ELEVATIONS. PRIMARY CONCERN WOULD BE FOR LOCALLY HEAVY RAINFALL TO IMPACT ONE OF THE BURN SCARS SUNDAY...HOWEVER...WITH ENOUGH SURFACE HEATING... INSTABILITY...AND FAVORABLE WIND SHEAR PROFILES...A FEW OF THE STORMS COULD BECOME STRONG TO SEVERE. THIS GENERAL PATTERN CONTINUES THROUGH TUESDAY ALTHOUGH CAPES AND DEWPOINTS DECREASE MONDAY AND TUESDAY WHICH WILL LIMIT THE COVERAGE...INTENSITY...AND RAINFALL POTENTIAL OF THUNDERSTORMS. ON WEDNESDAY...A STRONG UPPER LEVEL DISTURBANCE MOVES SOUTH THROUGH THE BACKSIDE OF THE TROF AXIS AND CLOSES OFF OVER THE HIGH PLAINS THURSDAY. GFS FORECASTS THE CLOSED LOW TO RETROGRADE FRIDAY TO SOUTHWESTERN SOUTH DAKOTA. THE ECMWF KEEPS THE CLOSED LOW FARTHER SOUTH...OVER WESTERN KS AND THE OK/TX PANHANDLES. THE GFS SCENARIO...WHICH HAS BEEN CONSISTENT FOR A FEW RUNS NOW...KEEPS SOUTHEAST COLORADO IN A COOL AND ACTIVE PATTERN WITH THUNDERSTORM CHANCES EACH DAY FROM WEDNESDAY THRU FRIDAY. THE ECMWF SCENARIO KEEPS BEST PRECIPITATION CHANCES TO THE SOUTH AND EAST OF THE CWA. STILL EXPECT THE COOLER TEMPERATURES AND INCREASED RELATIVE HUMDITIES TO BRING SOME RELIEF TO WILDFIRE THREAT. STARK && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 256 PM MDT FRI JUN 28 2013 THUNDERSTORMS AND ASSOCIATED OUTFLOW WINDS WILL CONTINUE TO BE THE MAIN CONCERN AT KALS...KCOS...AND KPUB TONIGHT AND SATURDAY AFTERNOON. THE BEST CHANCE FOR THUNDERSTORMS WILL BE AT KCOS AND THE SURROUNDING MOUNTAINS. MVFR CONDITIONS WILL BE POSSIBLE LATER THIS AFTERNOON AND EVENING AT KCOS. VFR CONDITIONS ARE EXPECTED AT KALS AND KPUB THROUGH SATURDAY EVENING. -PJC && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PJC LONG TERM...STARK AVIATION...PJC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
130 PM EDT FRI JUN 28 2013 .SYNOPSIS... A BROAD AREA OF LOW PRESSURE WILL REMAIN OVER THE NORTHEAST AND IMPACT THE REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE BERMUDA HIGH WILL STRENGTHEN AND BUILD BACK TOWARD THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CAPES ALREADY RUNNING 1500-2500 J/KG ACROSS MOST OF THE TRI-STATE AT 16Z PER LAPS ANALYSIS. HOWEVER CORE OF LOW LEVEL JET IS TO THE EAST...AND THE REGION IS IN THE RIGHT FRONT QUADRANT OF AN 80+ KT 250 HPA JET PER 12Z RAOBS. SO WHILE HAVE THE CAPE...NOT THE MUCH THE WAY IN FORCING TO PLAY WITH...OUTSIDE OF RESIDUAL BOUNDARIES FROM YESTERDAY/S CONVECTION AND LINGERING TROUGH OVER THE LOWER HUDSON VALLEY/NE NJ. LATEST HRRR AND RUC PAINT A PICTURE OF ISOLD- SCT CONVECTION FOR REMAINDER OF THE DAY AND THE FORECAST IS CONSISTENT WITH THIS. TEMPERATURE FORECAST FOR SLIGHTLY ABOVE NORMAL HIGHS APPEARS ON TRACK. THERE IS A HIGH RISK OF RIP CURRENTS AT ALL ATLANTIC OCEAN BEACHES THROUGH THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... CONVECTION SHOULD DIE DOWN DURING THE EVENING AS IT MOVES EAST ACROSS LONG ISLAND AND SOUTHERN CT...BUT THEN ANOTHER ROUND OF SHOWERS AND POSSIBLE TSTMS IS LIKELY LATE TONIGHT INTO SAT MORNING...ESPECIALLY EAST ACROSS LONG ISLAND AND SOUTHERN CT...AS A WEAK MID LEVEL IMPULSE MOVES UP THE COAST. LAST TWO RUNS OF THE ECMWF HAVE BEEN MOST AGGRESSIVE WITH THIS FEATURE...HAVE ACCEPTED THIS IDEA BUT TEMPERED WITH THE WEAKER GFS SOLUTION. TEMPERATURES SHOULD CONTINUE TO RUN SLIGHTLY ABOVE SEASONAL NORMS. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... THE UNSETTLED WEATHER PATTERN CONTINUES THIS WEEKEND INTO THE BEGINNING OF NEXT WEEK WITH THE ONGOING THREAT FOR SHOWERS AND THUNDERSTORMS AS THE REGION SITS BETWEEN A STRONG BERMUDA HIGH/UPPER LEVEL RIDGE TO THE EAST AND A DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION. THIS SYNOPTIC SET UP PROVIDES A CONTINUAL SOUTHERLY FLOW...USHERING IN WARM...VERY MOIST AIR. THE LATEST 00Z MODEL RUNS HAVE GENERALLY GOOD AGREEMENT ON THE PLACEMENT OF THESE FEATURES...WITH ONLY SLIGHT DIVERGENCE TOWARDS THE END OF THE FORECAST PERIOD. SURFACE LOW HOVERS OVER SOUTHEASTERN CANADA SAT NIGHT...WITH A STATIONARY FRONT POSITIONED THROUGH THE TRI STATE AREA. 00Z MODELS HINT OF A BRIEF PERIOD OF DRYING OUT...WITH PW VALUES ONLY AROUND 1.2/1.3 INCHES FOR SAT NIGHT. MADE MENTION OF CHANCE OF SHOWERS/THUNDERSTORMS SAT NIGHT AS A SHORTWAVE PIVOTS AROUND THE EASTERN SIDE OF THE UPPER LEVEL TROUGH. BEST COMBO OF INSTABILITY/SHEAR LOOKS TO BE FARTHER INLAND NORTH AND WEST OF THE CITY...BUT A STRONGER TSTM IS POSSIBLE WITH INSTABILITY VALUES BETWEEN 1000-1500 J/KG AND 0-6KM SHEAR BETWEEN 30 AND 35 KTS. AS THE NEXT SURFACE LOW TRACKS ALONG THE FRONT TO THE NORTHEAST SUNDAY...PW VALUES INCREASE GREATLY OVER THE AREA...WITH VALUES AROUND 2.0 INCHES EXPECTED BY THE AFTERNOON ALONG THE CONTINUAL SOUTHERLY FLOW. SHEAR AND INSTABILITY VALUES REMAIN MARGINAL...WITH THE THINKING THAT HEAVY RAIN WILL BE THE MAIN THREAT WITH ANY SHOWERS AND THUNDERSTORMS THAT FORM SUNDAY. SHOWERS AND THUNDERSTORMS REMAIN LIKELY IN THE FORECAST FOR THE FIRST PART OF THE WEEK WITH THE STATIONARY FRONT HUGGING THE NORTHEAST AND MULTIPLE SHORTWAVES SQUEEZING BETWEEN THE UPPER LEVEL TROUGH TO THE WEST AND THE RIDGE TO THE EAST. BY TUESDAY...THE BERMUDA HIGH/UPPER LEVEL RIDGE NUDGES INTO THE NORTHEAST...DIMINISHING THE THREAT FOR WIDESPREAD PRECIPITATION. THE THREAT FOR THUNDERSTORMS BECOMES MORE DIURNAL AT THIS POINT WITH THE PASSING SHORTWAVES COMBINED WITH DAY TIME HEATING BECOMING THE MAIN TRIGGER RATHER THAN THE FRONTAL BOUNDARY. HAVE INCLUDED CHANCE POPS TO ACCOUNT FOR THIS THROUGH THE END OF THE WEEK...WITH SOME DRYING FINALLY EXPECTED BY FRIDAY AS THE RIDGE AND SURFACE HIGH TAKE MORE CONTROL OF THE NORTHEAST AS THE UPPER LEVEL TROUGH FINALLY WEAKENS AND PROGRESSES EAST. TEMPS NEAR NORMAL FOR THE PERIOD...WITH HIGHS GENERALLY IN THE 80S AND LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... GENERALLY VFR THROUGH THIS AFTERNOON. SOME PATCHY MVFR CIGS/VSBYS POSSIBLE ACROSS EASTERN TERMINALS THROUGH 21Z. SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP/APPROACH WESTERN TERMINALS BY 22Z...MOVE THROUGH CITY TERMINALS THROUGH 01Z BEFORE WEAKENING AND MOVING THROUGH EASTERN TERMINALS BY 04Z-05Z. ISOLATED DEVELOPMENT POSSIBLE AHEAD OF THIS BUT CONFIDENCE TOO LOW IN LOCATION/TIMING FOR INCLUSION IN TAFS. WINDS LIGHTEN OVERNIGHT WITH CONFIDENCE INCREASING IN MVFR TO IFR CONDITIONS AT COASTAL TERMINALS. POSSIBLY LOWER IN SPOTS. CIGS/VSBYS LIFT AFTER 13Z SATURDAY. 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) KEWR FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KLGA FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KTEB FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KHPN FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KISP FCSTER COMMENTS: AMENDMENTS MAY BE NEEDED FOR SHOWERS. .OUTLOOK FOR 18Z SAT THROUGH WEDNESDAY... .SAT-WED...SUB VFR POSSIBLE AT TIMES WITH PERIODS OF SHOWERS AND TSTMS. && .MARINE... MINOR CHANGES MADE THIS UPDATE TO REFLECT THE LATEST CHANGES IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. SCA REMAINS UP ON THE OCEAN WATERS INTO SATURDAY WITH SEAS AROUND 5 FT...AND POSSIBLE GUSTS UP TO 25 KTS. SCA CONDITIONS EXPECTED ON THE OCEAN WATERS THROUGH THE WEEKEND WITH SEAS BETWEEN 7 AND 9 FT. WIND GUSTS MAY TOUCH 25 KTS AS WELL DURING THIS TIME. SEAS REMAIN ELEVATED DURING THE COMING WEEK WITH A PERSISTENT SOUTHERLY FLOW CONTINUALLY BUILDING UP THE SEAS. WINDS HOWEVER EXPECTED TO REMAIN BELOW SCA CRITERIA...SO ALL WATERS OTHER THAN THE OCEAN SHOULD REMAIN SUB SCA. WILL CONTINUE TO UNDERCUT WAVE WATCH III SEAS BY A FOOT OR SO. && .HYDROLOGY... CONFIDENCE IN FLASH FLOOD WATCH IS DECREASING. IF CURRENT CONVECTIVE TRENDS HOLD...COULD CANCEL THIS AFTERNOON...BUT FOR NOW WILL LEAVE UP FOR NYC/NE NJ/LOWER HUDSON VALLEY/SW CT. SHOWERS AND THUNDERSTORMS SUNDAY INTO MONDAY MAY PRODUCE HEAVY RAINFALL...WITH LOCALIZED FLOODING...ESPECIALLY OVER URBAN AND POOR DRAINAGE AREAS. STILL TOO EARLY AT THIS TIME TO DETERMINE RAINFALL TOTALS. FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR CTZ005-006- 009-010. NY...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR NYZ067>075- 176>179. NJ...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR NJZ002-004- 006-103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...GOODMAN/SEARS NEAR TERM...GOODMAN/MALOIT SHORT TERM...GOODMAN LONG TERM...SEARS AVIATION...BC MARINE...GOODMAN/MALOIT/SEARS HYDROLOGY...GOODMAN/SEARS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1257 PM EDT FRI JUN 28 2013 .SYNOPSIS... A BROAD AREA OF LOW PRESSURE WILL REMAIN OVER THE NORTHEAST AND IMPACT THE REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE BERMUDA HIGH WILL STRENGTHEN AND BUILD BACK TOWARD THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CAPES ALREADY RUNNING 1500-2500 J/KG ACROSS MOST OF THE TRI-STATE AT 16Z PER LAPS ANALYSIS. HOWEVER CORE OF LOW LEVEL JET IS TO THE EAST...AND THE REGION IS IN THE RIGHT FRONT QUADRANT OF AN 80+ KT 250 HPA JET PER 12Z RAOBS. SO WHILE HAVE THE CAPE...NOT THE MUCH THE WAY IN FORCING TO PLAY WITH...OUTSIDE OF RESIDUAL BOUNDARIES FROM YESTERDAY/S CONVECTION AND LINGERING TROUGH OVER THE LOWER HUDSON VALLEY/NE NJ. LATEST HRRR AND RUC PAINT A PICTURE OF ISOLD- SCT CONVECTION FOR REMAINDER OF THE DAY AND THE FORECAST IS CONSISTENT WITH THIS. TEMPERATURE FORECAST FOR SLIGHTLY ABOVE NORMAL HIGHS APPEARS ON TRACK. THERE IS A HIGH RISK OF RIP CURRENTS AT ALL ATLANTIC OCEAN BEACHES THROUGH THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... CONVECTION SHOULD DIE DOWN DURING THE EVENING AS IT MOVES EAST ACROSS LONG ISLAND AND SOUTHERN CT...BUT THEN ANOTHER ROUND OF SHOWERS AND POSSIBLE TSTMS IS LIKELY LATE TONIGHT INTO SAT MORNING...ESPECIALLY EAST ACROSS LONG ISLAND AND SOUTHERN CT...AS A WEAK MID LEVEL IMPULSE MOVES UP THE COAST. LAST TWO RUNS OF THE ECMWF HAVE BEEN MOST AGGRESSIVE WITH THIS FEATURE...HAVE ACCEPTED THIS IDEA BUT TEMPERED WITH THE WEAKER GFS SOLUTION. TEMPERATURES SHOULD CONTINUE TO RUN SLIGHTLY ABOVE SEASONAL NORMS. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... THE UNSETTLED WEATHER PATTERN CONTINUES THIS WEEKEND INTO THE BEGINNING OF NEXT WEEK WITH THE ONGOING THREAT FOR SHOWERS AND THUNDERSTORMS AS THE REGION SITS BETWEEN A STRONG BERMUDA HIGH/UPPER LEVEL RIDGE TO THE EAST AND A DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION. THIS SYNOPTIC SET UP PROVIDES A CONTINUAL SOUTHERLY FLOW...USHERING IN WARM...VERY MOIST AIR. THE LATEST 00Z MODEL RUNS HAVE GENERALLY GOOD AGREEMENT ON THE PLACEMENT OF THESE FEATURES...WITH ONLY SLIGHT DIVERGENCE TOWARDS THE END OF THE FORECAST PERIOD. SURFACE LOW HOVERS OVER SOUTHEASTERN CANADA SAT NIGHT...WITH A STATIONARY FRONT POSITIONED THROUGH THE TRI STATE AREA. 00Z MODELS HINT OF A BRIEF PERIOD OF DRYING OUT...WITH PW VALUES ONLY AROUND 1.2/1.3 INCHES FOR SAT NIGHT. MADE MENTION OF CHANCE OF SHOWERS/THUNDERSTORMS SAT NIGHT AS A SHORTWAVE PIVOTS AROUND THE EASTERN SIDE OF THE UPPER LEVEL TROUGH. BEST COMBO OF INSTABILITY/SHEAR LOOKS TO BE FARTHER INLAND NORTH AND WEST OF THE CITY...BUT A STRONGER TSTM IS POSSIBLE WITH INSTABILITY VALUES BETWEEN 1000-1500 J/KG AND 0-6KM SHEAR BETWEEN 30 AND 35 KTS. AS THE NEXT SURFACE LOW TRACKS ALONG THE FRONT TO THE NORTHEAST SUNDAY...PW VALUES INCREASE GREATLY OVER THE AREA...WITH VALUES AROUND 2.0 INCHES EXPECTED BY THE AFTERNOON ALONG THE CONTINUAL SOUTHERLY FLOW. SHEAR AND INSTABILITY VALUES REMAIN MARGINAL...WITH THE THINKING THAT HEAVY RAIN WILL BE THE MAIN THREAT WITH ANY SHOWERS AND THUNDERSTORMS THAT FORM SUNDAY. SHOWERS AND THUNDERSTORMS REMAIN LIKELY IN THE FORECAST FOR THE FIRST PART OF THE WEEK WITH THE STATIONARY FRONT HUGGING THE NORTHEAST AND MULTIPLE SHORTWAVES SQUEEZING BETWEEN THE UPPER LEVEL TROUGH TO THE WEST AND THE RIDGE TO THE EAST. BY TUESDAY...THE BERMUDA HIGH/UPPER LEVEL RIDGE NUDGES INTO THE NORTHEAST...DIMINISHING THE THREAT FOR WIDESPREAD PRECIPITATION. THE THREAT FOR THUNDERSTORMS BECOMES MORE DIURNAL AT THIS POINT WITH THE PASSING SHORTWAVES COMBINED WITH DAY TIME HEATING BECOMING THE MAIN TRIGGER RATHER THAN THE FRONTAL BOUNDARY. HAVE INCLUDED CHANCE POPS TO ACCOUNT FOR THIS THROUGH THE END OF THE WEEK...WITH SOME DRYING FINALLY EXPECTED BY FRIDAY AS THE RIDGE AND SURFACE HIGH TAKE MORE CONTROL OF THE NORTHEAST AS THE UPPER LEVEL TROUGH FINALLY WEAKENS AND PROGRESSES EAST. TEMPS NEAR NORMAL FOR THE PERIOD...WITH HIGHS GENERALLY IN THE 80S AND LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... LOW PRESSURE CURRENTLY MOVING AWAY FROM THE REGION TO THE NORTH. A FRONTAL BOUNDARY STALLS OVER THE AREA TODAY. BRIEF SHRA POSSIBLE ACROSS CITY AND INTERIOR TERMINALS LATE THIS MORNING. MINIMAL IMPACT TO OPERATIONS EXPECTED. SCT SHRA AND TSTMS POSSIBLE LATER WITH BETTER OVERALL CHANCES IN THE LATE AFTERNOON INTO EVENING AND HAVE SHOWN THAT VIA TEMPO GROUP EVERYWHERE EXCEPT ISP/GON. GENERALLY VFR...EXCEPT FOR EASTERN TERMINALS...WHICH MAY SEE MVFR CIGS THROUGHOUT THE DAY. MODERATE CONFIDENCE IN GUSTS DEVELOPING BY 16-17Z. 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) KEWR FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. OCCASIONAL MVFR CEILINGS POSSIBLE THROUGH 19-20Z. KLGA FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. OCCASIONAL MVFR CEILINGS POSSIBLE THROUGH 18Z. KTEB FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KHPN FCSTER COMMENTS: LOW-MODERATE CONFIDENCE IN COVERAGE OF TSTMS. KISP FCSTER COMMENTS: OCCASIONAL MVFR CEILINGS POSSIBLE THROUGH 18Z. .OUTLOOK FOR 15Z SAT THROUGH TUESDAY... .SAT-TUE...SUB VFR POSSIBLE AT TIMES WITH PERIODS OF SHOWERS AND TSTMS. && .MARINE... MINOR CHANGES MADE THIS UPDATE TO REFLECT THE LATEST CHANGES IN OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK. SCA REMAINS UP ON THE OCEAN WATERS INTO SATURDAY WITH SEAS AROUND 5 FT...AND POSSIBLE GUSTS UP TO 25 KTS. SCA CONDITIONS EXPECTED ON THE OCEAN WATERS THROUGH THE WEEKEND WITH SEAS BETWEEN 7 AND 9 FT. WIND GUSTS MAY TOUCH 25 KTS AS WELL DURING THIS TIME. SEAS REMAIN ELEVATED DURING THE COMING WEEK WITH A PERSISTENT SOUTHERLY FLOW CONTINUALLY BUILDING UP THE SEAS. WINDS HOWEVER EXPECTED TO REMAIN BELOW SCA CRITERIA...SO ALL WATERS OTHER THAN THE OCEAN SHOULD REMAIN SUB SCA. WILL CONTINUE TO UNDERCUT WAVE WATCH III SEAS BY A FOOT OR SO. && .HYDROLOGY... CONFIDENCE IN FLASH FLOOD WATCH IS DECREASING. IF CURRENT CONVECTIVE TRENDS HOLD...COULD CANCEL THIS AFTERNOON...BUT FOR NOW WILL LEAVE UP FOR NYC/NE NJ/LOWER HUDSON VALLEY/SW CT. SHOWERS AND THUNDERSTORMS SUNDAY INTO MONDAY MAY PRODUCE HEAVY RAINFALL...WITH LOCALIZED FLOODING...ESPECIALLY OVER URBAN AND POOR DRAINAGE AREAS. STILL TOO EARLY AT THIS TIME TO DETERMINE RAINFALL TOTALS. FOR DETAILS ON SPECIFIC AREA RIVERS AND STREAMS...INCLUDING OBSERVED AND FORECAST RIVER STAGES...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR CTZ005-006- 009-010. NY...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR NYZ067>075- 176>179. NJ...FLASH FLOOD WATCH UNTIL 9 PM EDT THIS EVENING FOR NJZ002-004- 006-103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ350-353- 355. && $$ SYNOPSIS...GOODMAN/SEARS NEAR TERM...MALOIT/GOODMAN SHORT TERM...GOODMAN LONG TERM...SEARS AVIATION...BC/DH MARINE...MALOIT/GOODMAN/SEARS HYDROLOGY...MALOIT/GOODMAN/SEARS
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
330 PM EDT FRI JUN 28 2013 .DISCUSSION... ...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE WEEKEND AND INTO EARLY NEXT WEEK... CURRENT/TONIGHT...SCATTERED LIGHTNING STORMS WILL MOVE ENE MAINLY N OF LAKE KISSIMMEE-CAPE CANAVERAL LINE THROUGH LATE AFTERNOON WITH ADDITIONAL CONVECTIVE ACTIVITY FOR SRN BREVARD/SRN OSCEOLA AND OKEECHOBEE COUNTY AND THE TREASURE COAST INTO THIS EVENING. LOW LVL SW FLOW WILL HOLD OFF THE SEA BRZ NORTH OF SEBASTIAN INLET WITH SEA BREEZE BOUNDARY JUST MAKING IT ONTO THE MAINLAND ALONG THE SRN TREASURE COAST. WILL CONTINUE HIGHEST EVENING POPS NEAR THE COAST AND SRN SECTIONS AND ONLY A SLIGHT CHANCE FOR LINGERING ACTIVITY PAST 8 PM ACROSS THE NRN INTERIOR. HRRR MODEL INDICATES MUCH OF THE ACTIVITY ACROSS NRN SECTIONS WILL MAKE IT INTO THE TREASURE COAST DURING THE EARLY EVENING. COULD SEE A FEW STRONG EVENING STORMS WITH STRONG WINDS...LOCALLY HEAVY RAIN AND FREQUENT LIGHTNING. SAT-MON...A STORMY WEEKEND IS SHAPING UP EACH AFTERNOON AS DEEP AND MOIST SW FLOW AHEAD OF AN MID LAYER TROUGH DIGGING FROM THE OHIO VALLEY INTO THE SE STATES ALLOWS NUMEROUS SHOWERS AND STORMS TO MOVE NORTHEAST EACH DAY WITH SOME ACTIVITY LINGERING INTO THE EVENING HOURS. FOR SATURDAY...WILL SHOW HIGHEST POPS NORTH NEAR THE DEEPEST MOISTURE ACROSS THE NRN PENINSULA AND ALSO ACROSS MARTIN COUNTY WHERE DEEPER MOISTURE WILL MOVE UP FROM SOUTH FL. FOR SUNDAY AND MONDAY WILL GO WITH LIKELY RAIN CHANCES EACH DAY (60 PCT) WITH NUMEROUS SHOWERS AND STORMS EXPECTED. INCREASED CLOUD COVER IS EXPECTED ESPEC SUNDAY INTO MONDAY. HIGHS WILL BE NEAR 90 TO THE LOWER 90S. STEERING FLOW WILL BE FROM THE SW AT 15-20 KNOTS ON SAT AND 20-25 KNOTS MAKING FOR FASTER NE STORM MOTION TOWARD THE COAST AND NEAR SHORE ATLANTIC WATERS EACH DAY. STRONG STORMS OVER THE WEEKEND MAY CONTAIN SMALL HAIL...FREQUENT LIGHTNING AND GUSTY WINDS ESPECIALLY WITH THE STRONGER ENVIRONMENTAL FLOW. BOATERS AND BEACHGOERS SHOULD CHECK THE RADAR AND FORECAST BEFORE HEADING TO THE BEACH...INTRACOASTAL WATERS OR ATLC THIS WEEKEND INTO MONDAY. TUE-THU...PREVIOUS EXTENDED DISCUSSION... TROFFING PATTERN OVER THE ERN CONUS WILL DAMPEN OUT THRU THE MIDDLE OF NEXT WEEK AS THE H30-H20 JET SHIFTS FROM A SLIGHT DIGGING TO A FULL LIFTING ORIENTATION. ATLC RIDGE AXIS WILL RESPOND BY DRIFTING BACK N INTO CENTRAL FL. THE RESULT WILL BE A WEAKENING STEERING FLOW THAT WILL BACK TO THE S/SE...PROMOTING THE FORMATION OF THE EAST COAST SEA BREEZE. INCREASING LOW/MID LVL SUPPRESSION AND WEAKENING STEERING FLOW WILL DECREASE PRECIP COVERAGE BACK TO SCT COVERAGE. NO SIG CHANGE IN AIRMASS...MAX TEMPS WITHIN A FEW DEGS OF CLIMO AVG (L90S) AREAWIDE. DVLPG ONSHORE FLOW WILL KEEP MIN TEMPS ALONG THE COAST BTWN 3-5F ABV AVG (M/U70S)...INTERIOR MIN TEMPS NEAR AVG (L/M70S). && .AVIATION...CONVECTIVE ACTIVITY AFFECTING NRN TERMINALS SHOULD TRANSITION SOUTH THIS EVENING FROM KMLB-KVRB FROM 20Z-23Z AND KFPR-KSUA FROM 21Z-24Z. MVFR CIGS WITH LCL IFR VSBYS WILL ACCOMPANY TSRA THIS AFTN/EVENING. SCT/NMRS TSRA WILL AFFECT E CENTRAL FL TERMINALS AGAIN ON SATURDAY...MAINLY AFT 18Z. && .MARINE... INCREASING SSW/SW WINDS OVER THE WEEKEND INTO MONDAY AND THUNDERSTORMS MOVING FROM THE MAINLAND TO THE NEAR SHORE WATERS AND OFFSHORE EACH DAY WILL KEEP THE WEATHER UNSETTLED FOR SMALL CRAFT INTO EARLY NEXT WEEK. SSW WINDS WILL INCREASE TO 15-20 KNOTS OFFSHORE THIS WEEKEND WITH SEAS TO 4-5 FT...LOWER NEAR THE IMMEDIATE COAST. STORM COVERAGE MAY REMAIN HIGH INTO MONDAY BEFORE TRANSITIONING TO SE FLOW BY WED/THU OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... DAB 76 91 75 90 / 30 60 50 60 MCO 74 92 74 91 / 20 60 50 60 MLB 75 91 77 89 / 30 50 40 60 VRB 75 91 76 89 / 30 50 40 60 LEE 76 92 76 91 / 20 60 50 60 SFB 76 92 76 92 / 20 60 50 60 ORL 76 92 76 92 / 20 60 50 60 FPR 75 91 75 90 / 30 40 30 60 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT-LONG TERM/AVIATION...VOLKMER RADAR/IMPACT WX UPDATES....SEDLOCK
AREA FORECAST DISCUSSION
NWS MIAMI FL
222 PM EDT FRI JUN 28 2013 .SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)... CURRENTLY, SOUTH FLORIDA CONTINUES TO BE MAINLY INFLUENCED BY THE DEEP LAYER RIDGE WHICH STRETCHES ACROSS THE REGION INTO THE ATLANTIC. THIS HAS RESULTED IN MAINTAINING A STEERING FLOW THAT IS NEARLY NONEXISTENT WITH ERRATIC STORM MOTION. HOWEVER, AS THE DAY PROGRESSES A MID LEVEL TROUGH WILL BE DEEPENING ACROSS THE EASTERN U.S. WHICH IN TURN WILL SHIFT THE RIDGE BOTH ALOFT AND AT THE SURFACE INTO THE FLORIDA STRAITS BY TONIGHT. HINTS OF THIS OCCURRING ARE BECOMING EVIDENT IN THE RADAR AND SATELLITE SIGNATURES WITH A VERY SLOW DRIFT TO THE NORTHEAST. THE HRRR IS COMING MORE IN LINE WITH THAT THINKING ALSO. THE ONLY CONCERN IS THAT THE HRRR ALSO IS SHOWING GOOD DEVELOPMENT BY 18Z WHICH HAS YET TO OCCUR SO TRENDED LATER WITH THE HIGHER CHANCES OF CONVECTION. GLOBAL MODELS CONTINUE WITH THE EVOLUTION OF THE TROUGH DEEPENING IT THROUGH SUNDAY. AS THIS OCCURS, THE STEERING FLOW WILL BECOME MORE SOUTHWEST ON SATURDAY WITH THE HIGHEST CHANCES FOR RAIN OVER THE INTERIOR AND MOST OF THE EAST COAST METRO REGION. THE PRIMARY THREAT WILL BE LOCALLY HEAVY RAINFALL POSSIBLE ALTHOUGH STORM MOTION WILL PICK UP TO BETWEEN 5 AND 10 KNOTS AND RELATIVELY WEAK MID LEVEL LAPSE RATES. THE MODELS ARE NOW SHOWING THE TROUGH DEEPENING EVEN FURTHER ON SUNDAY WITH A BLOCKING PATTERN SETTING UP ACROSS NORTH AMERICA AS MASSIVE RIDGES WILL BE IN EXISTENCE OVER THE DESERT SOUTHWEST AND THE WESTERN ATLANTIC. THIS WILL ALSO DEVELOP AN EVEN STRONGER DEEP SOUTHWEST STEERING FLOW. IN FACT, FORECAST SOUNDINGS ARE SHOWING AROUND 20 KNOTS OF WIND IN THE LOW LEVELS FROM ABOUT 2-7K FEET AND THIS ALONG WITH MID LEVEL LAPSE RATES STILL NOT VERY IMPRESSIVE COULD LIMIT THE AMOUNT OF THUNDER. THE KEY FACTOR WILL BE IF A EAST COAST SEA BREEZE WILL BE ABLE TO DEVELOP WITH SUCH STRONG LOW LEVEL SOUTHWEST WINDS. THE PWAT IS FORECAST TO BE WELL ABOVE TWO INCHES SO CHANCES FOR RAIN WILL REMAIN HIGH BUT THERE COULD BE ONLY A FEW LIGHTNING STRIKES ESPECIALLY WITH THE CONVECTION THAT DEVELOPS EARLY IN THE DAY. AT THE SAME TIME HOWEVER, BOTH THE MAV AND MET GUIDANCE ARE SHOWING VERY HIGH CHANCES FOR THUNDER. SO FOR THE TIME BEING WILL NOT CHANGE THE FORECAST FOR SUNDAY AND WILL WAIT FOR FURTHER GUIDANCE TO MAKE A DECISION ON WHETHER TO LOWER CHANCES FOR LIGHTNING STRIKES. ALL IN ALL THOUGH, IT IS SHAPING UP TO BE A WET WEEKEND FOR THE EAST COAST METRO REGION ESPECIALLY ON SUNDAY. .LONG TERM (MONDAY THROUGH FRIDAY)... THE BLOCKING PATTERN WILL CONTINUE INTO EARLY NEXT WEEK WITH A VERY SLOW RETROGRESSION TO THE WEST IN THE OVERALL PATTERN BY THE MIDDLE OF NEXT WEEK. THIS WILL RESULT IN THE DEEP LAYER RIDGE EVER SO SLOWLY SHIFTING BACK TO THE NORTH. SO FOR TUESDAY, FORECAST SOUNDINGS ARE INDICATING A STEERING FLOW MORE SOUTHERLY AND THEN RETURNING TO A SOUTHEAST DIRECTION BY WEDNESDAY OR THURSDAY. THE PWAT WILL REMAIN AT NEAR TWO INCHES ALL OF NEXT WEEK SO THE CHANCES FOR RAIN WILL REMAIN HIGH BUT SHIFT BACK TO THE INTERIOR AND SOUTHWEST COAST BY WEDNESDAY THROUGH FRIDAY. && .AVIATION... WITH THE WINDS SHIFTING MORE TO THE SOUTH, CONVECTIVE ACTIVITY HAS BEEN MORE CHAOTIC. THE BERMUDA HIGH HAS WEAKENED, ALLOWING FOR MORE INSTABILITY. HOWEVER, THIS HAS JUST LEAD TO MANY SMALL, WEAK SHOWERS AND THUNDERSTORMS, RATHER THAN LARGE STRONG STORMS. GIVEN THIS, HAVE REDUCED COVERAGE OF VCTS IN THE TAF SITES FROM KFLL NORTH, ALTHOUGH, THEY MAY NEED TO BE ADDED BACK IN LATER TODAY. WITH ACTIVITY PERSISTING FROM KOPF, SOUTH, HAVE KEPT THE VCTS IN, AS WELL AS FOR KAPF. WINDS, DUE TO THE CONVECTION, HAVE ALSO BEEN CHAOTIC TODAY. HOWEVER, THEY SHOULD BECOME SOUTHERLY AS CONVECTION WANES ALONG THE COAST, WHICH APPEARS SOME SITES HAVE ALREADY BEGUN THE SHIFT. TONIGHT, WINDS WILL BECOME LIGHT AND VARIABLE AND CONVECTION SHOULD DIMINISH AFTER SUNSET. TOMORROW WILL SEE WINDS BECOME MORE SOUTHWESTERLY AND ANOTHER ROUND OF CONVECTION WILL BEGIN MID TO LATE MORNING. && .MARINE... THE WIND WILL BE MAINTAIN A SOUTH TO SOUTHWEST DIRECTION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. THE SEAS WILL BUILD SLIGHTLY BY SUNDAY IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT AND INCREASE IN SPEED AS A STRONG TROUGH DEEPENS OVER THE EASTERN STATES. A SCEC STATEMENT MAY BE NEEDED FOR A PORTION OF THE WATERS AS SPEEDS COULD INCREASE IN THE RANGE OF 15 TO 20 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 76 89 77 89 / 50 50 30 70 FORT LAUDERDALE 75 88 79 89 / 50 50 40 70 MIAMI 77 90 78 90 / 40 40 40 70 NAPLES 75 91 76 91 / 20 40 30 70 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...30/KOB AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
433 PM EDT FRI JUN 28 2013 .SYNOPSIS... A DEEPENING UPPER LEVEL TROUGH OVER THE EASTERN US...ALONG WITH ABUNDANT MOISTURE...WILL PROVIDE ABOVE NORMAL CHANCES OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... UPDATE: LATE AFTERNOON TEMPS IN THE LOW TO MID 90S. MODERATE TO STRONG INSTABILITY ACROSS THE AREA THIS AFTERNOON. SOME SUBSIDENCE STILL IN EFFECT...ALTHOUGH CUMULUS CLOUDS ARE DEVELOPING. LEE SIDE SURFACE TROUGH TO DEVELOP. BASED ON CURRENT 88D REGIONAL RADAR TRENDS...EXPECT LATE AFTERNOON CONVECTION EXPECTED TO DEVELOP AND CONTINUE TONIGHT. CONVECTION STRETCHING FROM CENTRAL VIRGINIA ACROSS THE PIEDMONT OF NC INTO THE MTS. ADDITIONAL CONVECTION ACROSS GA DEVELOPING...ESPECIALLY ACROSS CNTRL AND SOUTHERN GA. SOME OF THESE STORMS COULD BE STRONG AS THEY MOVE INTO THE MIDLANDS AND CSRA BY EARLY EVENING AND UP THROUGH MIDNIGHT. EXPECT ANOTHER MUGGY NIGHT AS TEMPERATURES ONLY FALL INTO THE LOWER/MIDDLE 70S WITH DEWPOINTS TEMPERATURES NEAR/ARND 70. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... UPPER LEVEL TROF TO DEEPEN OVER THE AREA DURING THE WEEKEND. THE SURFACE FRONT AND A COUPLE OF UPPER LEVEL SHORT WAVES WILL PROVIDE A FOCUS FOR SHOWERS AND THUNDERSTORMS. DEEP SOUTHWEST FLOW ALOFT WILL TRANSPORT MOISTURE/SEVERAL SHORT WAVE TRIGGERS AND MODERATELY UNSTABLE AIR MASS SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND...MAINLY DIURNAL. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... UPPER LEVEL TROF REMAINS OVER THE AREA THROUGH MUCH OF THE WEEK. THIS WILL CONTINUE THE PATTERN OF AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS. HOWEVER... BY THURSDAY THE TROF BEGINS TO LIFT OUT AND HIGH PRESSURE BEGINS TO BUILD IN FROM THE MID ATLANTIC AREA REDUCING THE CHANGE OF RAIN LATE IN THE WEEK AND INTO NEXT WEEKEND. TEMPS WILL IN THE UPPER 80S TO LOWER 90S DURING THE DAY AND IN THE LOWER 70S AT NIGHT. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... VFR CONDITIONS THROUGH LATE THIS AFTERNOON. WEST TO SOUTHWEST WINDS PROVIDING DOWNSLOPE FLOW/SUBSIDENCE. CLOUD BASES AROUND 4000 FEET WITH CIRRUS CLOUDS ABOVE. SHOWERS AND THUNDERSTORMS EXPECTED TO TO DEVELOP LATE THIS AFTERNOON AND EVENING AS AN UPPER LEVEL DISTURBANCE CROSSES THE REGION. OPTIMUM PERIOD FOR CONVECTION FROM 28/23Z TO 29/06Z. HAVE INCLUDED TEMPO GROUP IN TAFS FOR EVENING CONVECTION. THE NAM AND RUC MODELS ARE INDICATING IFR/MVFR CIGS DEVELOPING LATE TONIGHT INTO SATURDAY MORNING. SINCE CONFIDENCE IS LOW...HAVE NOT INCLUDED EARLY MORNING RESTRICTIONS. THE CHANCE FOR SCATTERED CONVECTION WILL CONTINUE ACROSS THE TAF SITES SATURDAY MORNING INTO THE AFTERNOON. EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS POSSIBLE EACH DAY IN MAINLY AFTERNOON/EVENING THUNDERSTORMS...AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS. && .CLIMATE... THROUGH THU JUNE 28TH...AUGUSTA GA BUSH FIELD HAS RECEIVED A TOTAL OF 10.52 INCHES OF RAIN SO FAR FOR THE MONTH OF JUNE. THIS HAS ALREADY ESTABLISHED JUNE 2013 AS THE 2ND WETTEST JUNE ON RECORD AT AUGUSTA. THE WETTEST JUNE ON RECORD AT AUGUSTA IS 10.59 INCHES SET IN 2004...SO TO ESTABLISH JUNE 2013 AS THE WETTEST JUNE ON RECORD AT AUGUSTA...AGS NEEDS TO RECEIVE 0.08 MORE INCHES OF RAIN THIS MONTH. ALTHOUGH WE DO NOT KEEP RECORDS FOR DANIEL FIELD...IT HAS RECEIVED 13.47 INCHES OF RAIN SO FAR FOR JUNE. QUITE A DRAMATIC DIFFERENCE FROM LAST JUNE AS AUGUSTA BUSH FIELD ONLY RECEIVED 2.48 INCHES FOR THE MONTH. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 77
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
156 PM EDT FRI JUN 28 2013 .SYNOPSIS... A DEEPENING UPPER LEVEL TROUGH OVER THE EASTERN US...ALONG WITH ABUNDANT MOISTURE...WILL PROVIDE ABOVE NORMAL CHANCES OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATE: EARLY AFTERNOON TEMPS IN THE LOW TO MID 90S. MODERATE TO STRONG INSTABILITY ACROSS THE AREA THIS AFTERNOON. SUBSIDENCE STILL IN EFFECT...ALTHOUGH CUMULUS CLOUDS ARE DEVELOPING. LEE SIDE SURFACE TROUGH TO DEVELOP. LATE AFTERNOON CONVECTION EXPECTED TO DEVELOP AND CONTINUE TONIGHT. PREVIOUS DISCUSSION: UPPER LEVEL RIDGE WILL CONTINUE BUILDING OVER THE WESTERN CONUS... WHILE CLOSED UPPER LOW CONTINUES TO SPIN OVER THE GREAT LAKES/MIDWEST...RESULTING IN A DEEPENING UPPER TROUGH OVER THE SOUTHEASTERN CONUS. MODELS CONTINUE TO INDICATE SOME DRIER AIR ENTERING OUR REGION EARLY TODAY...BUT MAINTAIN INDICATIONS OF AN UPPER DISTURBANCE AND BATCH OF CONVECTION SETTING UP TO OUR WEST AND NORTHWEST WHICH DRIFTS INTO THE MIDLANDS AND CSRA THIS EVENING. NOT MUCH CONVECTION EXPECTED BEFORE 21Z THOUGH...WITH TRIGGER LACKING/HIGH LFC...BUT AIR MASS SHOULD BECOME INCREASINGLY UNSTABLE. SO EXPECT MODERATE TO STRONG INSTABILITY AND HIGHEST PRECIPITABLE WATER ACROSS THE EAST MIDLANDS LATE. WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH SURFACE TROUGH ACROSS MIDLANDS THIS EVENING AND SUPPORT FOR NUMEROUS SHOWERS/THUNDERSTORMS FROM LOCAL WRF/SREF/SPC WRF...WENT WITH HIGH CHANCE TO LIKELY POPS. SHEAR APPEARS WEAKER THAN YESTERDAY BUT A FEW STORMS MAY BECOME SEVERE WITH DAMAGING WIND MAIN THREAT. HEAVY RAIN THREAT CONTINUES WITH HIGH PRECIPITABLE WATER. TEMPERATURES SHOULD BE WARMER THAN YESTERDAY DUE TO WARM ADVECTION/MORE INSOLATION. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... UPPER LEVEL TROF TO DEEPEN OVER THE AREA DURING THE WEEKEND. THE SURFACE FRONT AND A COUPLE OF UPPER LEVEL SHORT WAVES WILL PROVIDE A FOCUS FOR SHOWERS AND THUNDERSTORMS. DEEP SOUTHWEST FLOW ALOFT WILL TRANSPORT MOISTURE/SEVERAL SHORT WAVE TRIGGERS AND MODERATELY UNSTABLE AIR MASS SUPPORTS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND...MAINLY DIURNAL. && .LONG TERM / MONDAY THROUGH FRIDAY/... UPPER LEVEL TROF REMAINS OVER THE AREA THROUGH MUCH OF THE WEEK. THIS WILL CONTINUE THE PATTERN OF AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS. HOWEVER... BY THURSDAY THE TROF BEGINS TO LIFT OUT AND HIGH PRESSURE BEGINS TO BUILD IN FROM THE MID ATLANTIC AREA REDUCING THE CHANGE OF RAIN LATE IN THE WEEK AND INTO NEXT WEEKEND. TEMPS WILL IN THE UPPER 80S TO LOWER 90S DURING THE DAY AND IN THE LOWER 70S AT NIGHT. && .AVIATION /18Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS THROUGH THIS AFTERNOON. WEST TO SOUTHWEST WINDS PROVIDING DOWNSLOPE FLOW/SUBSIDENCE. CLOUD BASES AROUND 4000 FEET WITH CIRRUS CLOUDS ABOVE. SHOWERS AND THUNDERSTORMS EXPECTED TO TO DEVELOP LATE THIS AFTERNOON AND EVENING AS AN UPPER LEVEL DISTURBANCE CROSSES THE REGION. OPTIMUM PERIOD FOR CONVECTION FROM 28/23Z TO 29/06Z. HAVE INCLUDED TEMPO GROUP IN TAFS FOR EVENING CONVECTION. THE NAM AND RUC MODELS ARE INDICATING IFR/MVFR CIGS DEVELOPING LATE TONIGHT INTO SATURDAY MORNING. SINCE CONFIDENCE IS LOW...HAVE NOT INCLUDED EARLY MORNING RESTRICTIONS. THE CHANCE FOR SCATTERED CONVECTION WILL CONTINUE ACROSS THE TAF SITES SATURDAY MORNING INTO THE AFTERNOON. EXTENDED AVIATION OUTLOOK...CIG/VSBY RESTRICTIONS POSSIBLE EACH DAY IN MAINLY AFTERNOON/EVENING THUNDERSTORMS...AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS. && .CLIMATE... THROUGH THU JUNE 27TH...AUGUSTA GA BUSH FIELD HAS RECEIVED A TOTAL OF 10.52 INCHES OF RAIN SO FAR FOR THE MONTH OF JUNE. THIS HAS ALREADY ESTABLISHED JUNE 2013 AS THE 2ND WETTEST JUNE ON RECORD AT AUGUSTA. THE WETTEST JUNE ON RECORD AT AUGUSTA IS 10.59 INCHES SET IN 2004...SO TO ESTABLISH JUNE 2013 AS THE WETTEST JUNE ON RECORD AT AUGUSTA...AGS NEEDS TO RECEIVE 0.08 MORE INCHES OF RAIN THIS MONTH. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
309 PM CDT FRI JUN 28 2013 .MESOSCALE DISCUSSION... 230 PM CDT MONITORING GUSTY STORMS ACROSS NORTH CENTRAL TO NORTHEAST IL. A COUPLE ARCS OF CONVECTION HAVE DEVELOPED ON THE LEADING EDGE OF THE INCOMING SHORT WAVE. THIS LEADING EDGE HAS AN UNSTABLE ATMOSPHERE TO WORK WITH GIVEN SURFACE TEMPERATURES SEVERAL DEGREES ABOVE CONVECTIVE TEMPS PER MORNING SOUNDINGS AND AMDAR DATA. NICE INVERTED-V SHAPE SOUNDINGS ARE PRESENT UP TO 5000-6000 FT WITH ASSOCIATED DOWNDRAFT CAPE ANALYZED BY THE RAP IN EXCESS OF 800 J/KG. THE STORM MOVING ACROSS SOUTHERN KANE NOW HAS PRODUCED A 46 MPH GUST AT DEKALB...AN ESTIMATED 50 MPH GUST AT HINKLEY...AND A MEASURED 52 MPH GUST AT AURORA. THIS IS THE MOST ORGANIZED STORM BUT ANY OF THESE WILL HAVE THE POTENTIAL TO PRODUCE WINDS...AND POSSIBLY SOME SMALL HAIL. WILL CONTINUE WITH SPECIAL WEATHER STATEMENTS ON THESE BUT WOULD NOT BE SURPRISED TO HAVE A BRIEF SEVERE THUNDERSTORM WARNING OR TWO...ESPECIALLY ON THESE LEADING TWO ARCS. MTF && .DISCUSSION... 1135 AM CDT ONLY SOME MINOR TWEAKS TO SHORT TERM FORECAST GRIDS FOR THE REST OF TODAY AND THIS EVENING TO ACCOUNT FOR RECENT AND CURRENT TEMPERATURE...DEW POINT AND CLOUD TRENDS. A SMALL VORT MAX IN THE NW UPPER FLOW DROPPED SE TO SE WI OVERNIGHT PRODUCING SOME MINOR SHOWERS AND AN ISOLATED TS. BUT MID MORNING IT HAD MOVES OUT OF SOUTHERN LAKE MI AND IS CURRENTLY UPPER APPROACHING THE SW SHORE OF LOWER MI AND WILL NOT POSE ANY THREAT OF SHRA OR TS TO THE LOCAL AREA. UPSTREAM...WATER VAPOR SATELLITE LOOPS SHOW ANOTHER SHORT WAVE/VORT MAX HAS BEEN QUICKLY DROPPING SSE FROM E CENTRAL MN TO W CENTRAL WI THIS MORNING. NAM12 AND RUC13 SEEM TO HAVE A DECENT HANDLE ON THIS FEATURE AND TURN IT MORE SE AS IT STARTS TO ENTER THE BROAD UPPER TROUGH FROM THE UPPER MIDWEST E TO THE NEW ENGLAND COAST AND S TO THE MID MS...OH...AND TN VALLEYS...AND THE MID ATLANTIC COAST. EXTRAPOLATION OF RECENT MOVEMENT OF THE WI SHORT WAVE IS IN DECENT AGREEMENT WITH ABOVE MENTIONED MODELS BRINGING THE THE SHORT WAVE TROUGH S OF THE WI BORDER BETWEEN 20 AND 21Z. SIGNIFICANT MID LEVEL COOLING OCCUR ED SINCE YESTERDAY AND WHILE MODELS TEMPERATURE PROFILES SHOW WARMING DURING THE DAY BY 29.00Z THERE IS STILL A DEEP ALBEIT MUCH NARROW AREA OF CAPE OVER THE LOCAL AREA THAN THIS MORNING. STILL...WITH CONVECTIVE TEMPERATURES TO BE REACHED BY NOON EXPECT TO SEE QUICK CU DEVELOPMENT AHEAD OF LARGE AREA OF CLOUDS ADVECTING ACROSS SOUTHERN WI TOWARD NORTHERN IL AND NW IN. AS OF 1125 AM CDT RADAR COMPOSITE LOOP SHOWED ONLY SCATTERED SMALL LIGHT SHOWERS UPSTREAM OF THE LOCAL FORECAST AREA BUT WITH SOME ADDITIONAL HEATING AVAILABLE THROUGH DECREASING ML-CAPE OF 1200 TO 2000 J/KG DEPENDING ON WHICH MODEL OVER THE AREA AND DECENT UVV IN THE LOWER AND MID LEVELS AHEAD OF THE APPROACHING SHORT WAVE TROUGH FEEL THAT ALONG WITH INCREASING CLOUDY COVER TO BROKEN OR NEAR OVERCAST PROBABILITY OF SHOWERS WILL BE INCREASING TO LIKELY DURING THE AFTERNOON...WITH ALSO A SOME THUNDERSTORMS OCCURRING. TRS //PREV DISCUSSION... 339 AM CDT SYNOPSIS...THE LARGE SCALE PATTERN WILL NOT CHANGE MUCH OVER THE NEXT WEEK WITH A LARGE RIDGE OVER THE WESTERN U.S. AND A TROUGH OVER THE EASTERN U.S. STORMS ARE EXPECTED TODAY AND TOMORROW WITH A BRIEF DRY PERIOD EXPECTED EARLY NEXT WEEK. ALSO EXPECTED IS A COOL PERIOD AS NORTH FLOW SETS UP SATURDAY. TODAY AND TONIGHT... THE SURFACE LOW THAT IS CENTERED OVER NEW ENGLAND AND STRETCHES BACK TO LAKE SUPERIOR WILL SINK SOUTH TODAY. IN ADDITION THE UPPER LEVEL JET EXIT WILL ALSO BE SINKING SOUTH THROUGH THE CWA WITH THE LEFT JET EXIT REGION OVERHEAD DURING PRIME HEATING THIS AFTERNOON. LONG SKINNY CAPE OF UP TO 1000 J/KG IS FORECAST AND SHEAR WILL BE MINIMAL AT BEST...10 KT OR SO. THEREFORE EXPECTING SCATTERED STORMS TO SPROUT FIRST ALONG THE IL/WI STATE LINE AROUND NOON AND SCATTERED THUNDERSTORMS SHOULD SPREAD ACROSS THE CWA EARLY THIS AFTERNOON. LATER IN THE AFTERNOON AS THE WAVE COMES THROUGH EXPECTING THE MAIN THUNDERSTORM ACTIVITY TO BE EAST OF A NORTHWEST BOONE COUNTY TO SOUTH CENTRAL IROQUOIS COUNTY LINE. SCATTERED THUNDERSTORMS ARE CERTAINLY POSSIBLE WEST OF THAT LINE AS WELL...BUT THINKING THE STRONGER STORMS AND BETTER COVERAGE WILL BE EAST OF THE LINE. STORMS WILL LIKELY BE PULSEY AND UNORGANIZED AS THERE IS A DECENT AMOUNT OF CAPE BUT NOT ENOUGH SHEAR FOR LONG LIVED ORGANIZED STORMS. THE DIURNAL CONVECTION WILL WIND DOWN AFTER SUNSET WITH SCATTERED SHOWERS OVERNIGHT. ENJOY THE TEMPS TODAY BECAUSE A COOL DOWN IS EXPECTED TOMORROW. HIGHS WILL RANGE FROM AROUND 80 TO THE MID 80S. SATURDAY AND SUNDAY... WINDS TURN NORTH SATURDAY BEHIND THE UPPER LEVEL TROUGH AND MUCH COOLER AIR MOVES INTO THE REGION. THE UPPER LEVEL TROUGH SPLITS WITH THE SOUTHERN LOW BECOMING A CLOSED LOW OVER OHIO LATE SATURDAY NIGHT. YET ANOTHER UPPER LEVEL DISTURBANCE PASSES OVER THE WESTERN HALF OF THE CWA SPARKING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS PRIMARILY WEST OF THE CHICAGO METRO. CAPE WILL BE VERY LOW ON SATURDAY WITH MAYBE A FEW HUNDRED J/KG AVAILABLE. SHEAR WILL BE A BIT MORE FAVORABLE FOR ORGANIZED CONVECTION...BUT THINKING GENERAL THUNDERSTORMS WILL BE THE MAIN SHOW. THE DIURNAL SHOWERS AND THUNDERSTORMS DISSIPATE OVERNIGHT WITH LOW TEMPS FALLING INTO THE UPPER 50S. CLOUD COVER SHOULD REMAIN THICK ENOUGH TO KEEP TEMPS UP A BIT. ON SUNDAY THE UPPER LEVEL TROUGH RETROGRADES A BIT ACROSS THE OHIO RIVER VALLEY AND INSTABILITY ASSOCIATED WITH THE LOW MAY HELP A FEW SHOWERS AND THUNDERSTORMS FORM ON SUNDAY. AREAS ALONG AND SOUTH OF I-80 HAVE THE BEST CHANCE FOR A PASSING SHOWER OR THUNDERSTORM. COVERAGE SHOULD REMAIN SPARSE AND A RAIN OUT IS NOT EXPECTED. ANOTHER DRY NIGHT IS EXPECTED SUNDAY NIGHT. SUNDAY LOOKS A BIT WARMER WITH HIGHS IN THE MID 70S BUT CLOUDS SHOULD THIN SUNDAY NIGHT SO WENT A FEW DEGREES COOLER SUNDAY NIGHT. EXTENDED...MONDAY THROUGH THURSDAY... THE LARGE LOW PRESSURE REMAINS OVER THE EAST COAST WHILE HIGH PRESSURE SINKS SOUTH OUT OF CANADA REACHING THE CWA ON MONDAY. THE UPPER LEVEL TROUGH WILL REMAIN OVERHEAD THROUGHOUT THE EXTENDED WITH DISTURBANCES ROTATING AROUND IT. AS SUCH LEFT PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. TEMPS REMAIN BELOW NORMAL THANKS TO THE UPPER LEVEL LOW AND NORTHERLY SURFACE FLOW. HOWEVER LOOKING LIKE WE MIGHT SEE HIGHS IN THE 80S BY LATE NEXT WEEK. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * PERIODS OF SHRA WITH ISOLATED TSRA THROUGH 22Z. SOME STORMS MAY HAVE GUSTS IN EXCESS OF 40 MPH. * MVFR CIGS ARRIVING THIS EVENING WITH A GOOD CHANCE...ESPECIALLY FOR LATE JUNE...FOR IFR LATER TONIGHT INTO SAT MORNING. * NORTHWEST WINDS TURN NORTH LATE THIS EVENING/OVERNIGHT. * CHANCE FOR SHRA ON SAT AFTERNOON. //DISCUSSION...UPDATED 18Z... BROAD LOW PRESSURE ACROSS THE EASTERN GREAT LAKES AND NEW ENGLAND WILL CONTINUE TO PRESENT NORTHERLY FLOW OVER THE TAF SITES INTO THIS WEEKEND. AN UPPER LEVEL DISTURBANCE MOVING OVERHEAD THIS AFTERNOON INTO THE EARLY EVE WILL PRESENT THE GREATEST COVERAGE OF SHOWERS THROUGH THE NEXT 24 HOURS...WITH ISOLATED TO SCATTERED THUNDER LIKELY. SOME OF THESE INDIVIDUAL STORMS/SHOWERS COULD BE GUSTY GIVEN THE ENVIRONMENT...PUTTING OUT GUST FRONTS THAT WILL EXTEND A WAYS FROM THE ACTUAL RAIN. COVERAGE IS ANTICIPATED TO BE AROUND 70 PERCENT ACROSS CHICAGOLAND FROM 20Z-23Z. COVERAGE WILL BE SLOW TO WANE THROUGH 02Z-04Z THOUGH DIMINISHING INSTABILITY SHOULD ALLOW THE THUNDER THREAT TO DROP QUICKLY THIS EVE. NW WINDS WILL TURN NNE AT SOME POINT TONIGHT...THOUGH CONFIDENCE IN EXACT TIMING REMAINS LOW. WINDS LOOK TO BE NNE TO NE ON SAT...AT LEAST BY LATE MORNING INTO THE AFTERNOON WITH HIGHER CONFIDENCE. //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN SHRA WITH MEDIUM CONFIDENCE IN TSRA. HIGH CONFIDENCE IN DURATION OF SHRA AND TSRA...ALTHOUGH TIMES OF SHRA/TSRA AT THE AIRFIELD MAY BE BRIEF. * HIGH CONFIDENCE IN MVFR ARRIVING AT SOME POINT THIS EVE AND MEDIUM CONFIDENCE IN IFR. LOW CONFIDENCE IN IFR DURATION. * MEDIUM CONFIDENCE IN WIND DIRECTION AND SPEED. WINDS MAY TURN SHARPLY NEAR OUTFLOW BOUNDARIES FROM SHOWERS THIS AFTERNOON. * LOW CONFIDENCE IN SCT SHRA SAT AFTERNOON. //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...VFR. CHANCE FOR SHOWERS MONDAY EVENING. TUESDAY THROUGH THURSDAY...DRY AND VFR. MTF && .MARINE... 305 PM CDT A SPRAWLING AREA OF LOW PRESSURE OVER NEW YORK AND THE EASTERN GREAT LAKES WILL SLOWLY TRACK NORTHEAST INTO SOUTHERN QUEBEC BY TOMORROW AFTERNOON. A TROUGH OF LOW PRESSURE EXTENDING WEST FROM THIS LOW THROUGH CENTRAL LAKE MICHIGAN WILL PUSH SOUTH ACROSS THE LAKE...USHERING IN COOLER AIR AND STRONGER WINDS OVER LAKE MICHIGAN. IN GENERAL...WINDS SHOULD BE A LITTLE STRONGER OVER THE SOUTHERN PORTIONS OF THE LAKE WHERE THE PRESSURE GRADIENT WILL BE STRONGEST..TO 25KT...THOUGH THERE SHOULD BE PERIODS WHEN WINDS WILL DECREASE TO 10 TO 20 KT. WINDS WILL TURN NORTHERLY BEHIND THE TROUGH PASSAGE...AND REMAIN GENERALLY NORTHERLY THROUGH MONDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE NORTHERN PLAINS TO THE UPPER MISSISSIPPI VALLEY. THE HIGH WILL MOVE ACROSS WESTERN GREAT LAKES REGION ON TUESDAY...BRINGING SOME LIGHTER WINDS BEFORE TURNING MORE SOUTHERLY BY MIDWEEK AS THE HIGH SLIDES OFF TO THE EAST. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 PM SATURDAY TO 3 AM MONDAY. IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...9 AM SATURDAY TO 3 AM MONDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 PM CDT FRI JUN 28 2013 .MESOSCALE DISCUSSION... 230 PM CDT MONITORING GUSTY STORMS ACROSS NORTH CENTRAL TO NORTHEAST IL. A COUPLE ARCS OF CONVECTION HAVE DEVELOPED ON THE LEADING EDGE OF THE INCOMING SHORT WAVE. THIS LEADING EDGE HAS AN UNSTABLE ATMOSPHERE TO WORK WITH GIVEN SURFACE TEMPERATURES SEVERAL DEGREES ABOVE CONVECTIVE TEMPS PER MORNING SOUNDINGS AND AMDAR DATA. NICE INVERTED-V SHAPE SOUNDINGS ARE PRESENT UP TO 5000-6000 FT WITH ASSOCIATED DOWNDRAFT CAPE ANALYZED BY THE RAP IN EXCESS OF 800 J/KG. THE STORM MOVING ACROSS SOUTHERN KANE NOW HAS PRODUCED A 46 MPH GUST AT DEKALB...AN ESTIMATED 50 MPH GUST AT HINKLEY...AND A MEASURED 52 MPH GUST AT AURORA. THIS IS THE MOST ORGANIZED STORM BUT ANY OF THESE WILL HAVE THE POTENTIAL TO PRODUCE WINDS...AND POSSIBLY SOME SMALL HAIL. WILL CONTINUE WITH SPECIAL WEATHER STATEMENTS ON THESE BUT WOULD NOT BE SURPRISED TO HAVE A BRIEF SEVERE THUNDERSTORM WARNING OR TWO...ESPECIALLY ON THESE LEADING TWO ARCS. MTF && .DISCUSSION... 1135 AM CDT ONLY SOME MINOR TWEAKS TO SHORT TERM FORECAST GRIDS FOR THE REST OF TODAY AND THIS EVENING TO ACCOUNT FOR RECENT AND CURRENT TEMPERATURE...DEW POINT AND CLOUD TRENDS. A SMALL VORT MAX IN THE NW UPPER FLOW DROPPED SE TO SE WI OVERNIGHT PRODUCING SOME MINOR SHOWERS AND AN ISOLATED TS. BUT MID MORNING IT HAD MOVES OUT OF SOUTHERN LAKE MI AND IS CURRENTLY UPPER APPROACHING THE SW SHORE OF LOWER MI AND WILL NOT POSE ANY THREAT OF SHRA OR TS TO THE LOCAL AREA. UPSTREAM...WATER VAPOR SATELLITE LOOPS SHOW ANOTHER SHORT WAVE/VORT MAX HAS BEEN QUICKLY DROPPING SSE FROM E CENTRAL MN TO W CENTRAL WI THIS MORNING. NAM12 AND RUC13 SEEM TO HAVE A DECENT HANDLE ON THIS FEATURE AND TURN IT MORE SE AS IT STARTS TO ENTER THE BROAD UPPER TROUGH FROM THE UPPER MIDWEST E TO THE NEW ENGLAND COAST AND S TO THE MID MS...OH...AND TN VALLEYS...AND THE MID ATLANTIC COAST. EXTRAPOLATION OF RECENT MOVEMENT OF THE WI SHORT WAVE IS IN DECENT AGREEMENT WITH ABOVE MENTIONED MODELS BRINGING THE THE SHORT WAVE TROUGH S OF THE WI BORDER BETWEEN 20 AND 21Z. SIGNIFICANT MID LEVEL COOLING OCCUR ED SINCE YESTERDAY AND WHILE MODELS TEMPERATURE PROFILES SHOW WARMING DURING THE DAY BY 29.00Z THERE IS STILL A DEEP ALBEIT MUCH NARROW AREA OF CAPE OVER THE LOCAL AREA THAN THIS MORNING. STILL...WITH CONVECTIVE TEMPERATURES TO BE REACHED BY NOON EXPECT TO SEE QUICK CU DEVELOPMENT AHEAD OF LARGE AREA OF CLOUDS ADVECTING ACROSS SOUTHERN WI TOWARD NORTHERN IL AND NW IN. AS OF 1125 AM CDT RADAR COMPOSITE LOOP SHOWED ONLY SCATTERED SMALL LIGHT SHOWERS UPSTREAM OF THE LOCAL FORECAST AREA BUT WITH SOME ADDITIONAL HEATING AVAILABLE THROUGH DECREASING ML-CAPE OF 1200 TO 2000 J/KG DEPENDING ON WHICH MODEL OVER THE AREA AND DECENT UVV IN THE LOWER AND MID LEVELS AHEAD OF THE APPROACHING SHORT WAVE TROUGH FEEL THAT ALONG WITH INCREASING CLOUDY COVER TO BROKEN OR NEAR OVERCAST PROBABILITY OF SHOWERS WILL BE INCREASING TO LIKELY DURING THE AFTERNOON...WITH ALSO A SOME THUNDERSTORMS OCCURRING. TRS //PREV DISCUSSION... 339 AM CDT SYNOPSIS...THE LARGE SCALE PATTERN WILL NOT CHANGE MUCH OVER THE NEXT WEEK WITH A LARGE RIDGE OVER THE WESTERN U.S. AND A TROUGH OVER THE EASTERN U.S. STORMS ARE EXPECTED TODAY AND TOMORROW WITH A BRIEF DRY PERIOD EXPECTED EARLY NEXT WEEK. ALSO EXPECTED IS A COOL PERIOD AS NORTH FLOW SETS UP SATURDAY. TODAY AND TONIGHT... THE SURFACE LOW THAT IS CENTERED OVER NEW ENGLAND AND STRETCHES BACK TO LAKE SUPERIOR WILL SINK SOUTH TODAY. IN ADDITION THE UPPER LEVEL JET EXIT WILL ALSO BE SINKING SOUTH THROUGH THE CWA WITH THE LEFT JET EXIT REGION OVERHEAD DURING PRIME HEATING THIS AFTERNOON. LONG SKINNY CAPE OF UP TO 1000 J/KG IS FORECAST AND SHEAR WILL BE MINIMAL AT BEST...10 KT OR SO. THEREFORE EXPECTING SCATTERED STORMS TO SPROUT FIRST ALONG THE IL/WI STATE LINE AROUND NOON AND SCATTERED THUNDERSTORMS SHOULD SPREAD ACROSS THE CWA EARLY THIS AFTERNOON. LATER IN THE AFTERNOON AS THE WAVE COMES THROUGH EXPECTING THE MAIN THUNDERSTORM ACTIVITY TO BE EAST OF A NORTHWEST BOONE COUNTY TO SOUTH CENTRAL IROQUOIS COUNTY LINE. SCATTERED THUNDERSTORMS ARE CERTAINLY POSSIBLE WEST OF THAT LINE AS WELL...BUT THINKING THE STRONGER STORMS AND BETTER COVERAGE WILL BE EAST OF THE LINE. STORMS WILL LIKELY BE PULSEY AND UNORGANIZED AS THERE IS A DECENT AMOUNT OF CAPE BUT NOT ENOUGH SHEAR FOR LONG LIVED ORGANIZED STORMS. THE DIURNAL CONVECTION WILL WIND DOWN AFTER SUNSET WITH SCATTERED SHOWERS OVERNIGHT. ENJOY THE TEMPS TODAY BECAUSE A COOL DOWN IS EXPECTED TOMORROW. HIGHS WILL RANGE FROM AROUND 80 TO THE MID 80S. SATURDAY AND SUNDAY... WINDS TURN NORTH SATURDAY BEHIND THE UPPER LEVEL TROUGH AND MUCH COOLER AIR MOVES INTO THE REGION. THE UPPER LEVEL TROUGH SPLITS WITH THE SOUTHERN LOW BECOMING A CLOSED LOW OVER OHIO LATE SATURDAY NIGHT. YET ANOTHER UPPER LEVEL DISTURBANCE PASSES OVER THE WESTERN HALF OF THE CWA SPARKING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS PRIMARILY WEST OF THE CHICAGO METRO. CAPE WILL BE VERY LOW ON SATURDAY WITH MAYBE A FEW HUNDRED J/KG AVAILABLE. SHEAR WILL BE A BIT MORE FAVORABLE FOR ORGANIZED CONVECTION...BUT THINKING GENERAL THUNDERSTORMS WILL BE THE MAIN SHOW. THE DIURNAL SHOWERS AND THUNDERSTORMS DISSIPATE OVERNIGHT WITH LOW TEMPS FALLING INTO THE UPPER 50S. CLOUD COVER SHOULD REMAIN THICK ENOUGH TO KEEP TEMPS UP A BIT. ON SUNDAY THE UPPER LEVEL TROUGH RETROGRADES A BIT ACROSS THE OHIO RIVER VALLEY AND INSTABILITY ASSOCIATED WITH THE LOW MAY HELP A FEW SHOWERS AND THUNDERSTORMS FORM ON SUNDAY. AREAS ALONG AND SOUTH OF I-80 HAVE THE BEST CHANCE FOR A PASSING SHOWER OR THUNDERSTORM. COVERAGE SHOULD REMAIN SPARSE AND A RAIN OUT IS NOT EXPECTED. ANOTHER DRY NIGHT IS EXPECTED SUNDAY NIGHT. SUNDAY LOOKS A BIT WARMER WITH HIGHS IN THE MID 70S BUT CLOUDS SHOULD THIN SUNDAY NIGHT SO WENT A FEW DEGREES COOLER SUNDAY NIGHT. EXTENDED...MONDAY THROUGH THURSDAY... THE LARGE LOW PRESSURE REMAINS OVER THE EAST COAST WHILE HIGH PRESSURE SINKS SOUTH OUT OF CANADA REACHING THE CWA ON MONDAY. THE UPPER LEVEL TROUGH WILL REMAIN OVERHEAD THROUGHOUT THE EXTENDED WITH DISTURBANCES ROTATING AROUND IT. AS SUCH LEFT PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. TEMPS REMAIN BELOW NORMAL THANKS TO THE UPPER LEVEL LOW AND NORTHERLY SURFACE FLOW. HOWEVER LOOKING LIKE WE MIGHT SEE HIGHS IN THE 80S BY LATE NEXT WEEK. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * PERIODS OF SHRA WITH ISOLATED TSRA THROUGH 22Z. SOME STORMS MAY HAVE GUSTS IN EXCESS OF 40 MPH. * MVFR CIGS ARRIVING THIS EVENING WITH A GOOD CHANCE...ESPECIALLY FOR LATE JUNE...FOR IFR LATER TONIGHT INTO SAT MORNING. * NORTHWEST WINDS TURN NORTH LATE THIS EVENING/OVERNIGHT. * CHANCE FOR SHRA ON SAT AFTERNOON. //DISCUSSION...UPDATED 18Z... BROAD LOW PRESSURE ACROSS THE EASTERN GREAT LAKES AND NEW ENGLAND WILL CONTINUE TO PRESENT NORTHERLY FLOW OVER THE TAF SITES INTO THIS WEEKEND. AN UPPER LEVEL DISTURBANCE MOVING OVERHEAD THIS AFTERNOON INTO THE EARLY EVE WILL PRESENT THE GREATEST COVERAGE OF SHOWERS THROUGH THE NEXT 24 HOURS...WITH ISOLATED TO SCATTERED THUNDER LIKELY. SOME OF THESE INDIVIDUAL STORMS/SHOWERS COULD BE GUSTY GIVEN THE ENVIRONMENT...PUTTING OUT GUST FRONTS THAT WILL EXTEND A WAYS FROM THE ACTUAL RAIN. COVERAGE IS ANTICIPATED TO BE AROUND 70 PERCENT ACROSS CHICAGOLAND FROM 20Z-23Z. COVERAGE WILL BE SLOW TO WANE THROUGH 02Z-04Z THOUGH DIMINISHING INSTABILITY SHOULD ALLOW THE THUNDER THREAT TO DROP QUICKLY THIS EVE. NW WINDS WILL TURN NNE AT SOME POINT TONIGHT...THOUGH CONFIDENCE IN EXACT TIMING REMAINS LOW. WINDS LOOK TO BE NNE TO NE ON SAT...AT LEAST BY LATE MORNING INTO THE AFTERNOON WITH HIGHER CONFIDENCE. //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN SHRA WITH MEDIUM CONFIDENCE IN TSRA. HIGH CONFIDENCE IN DURATION OF SHRA AND TSRA...ALTHOUGH TIMES OF SHRA/TSRA AT THE AIRFIELD MAY BE BRIEF. * HIGH CONFIDENCE IN MVFR ARRIVING AT SOME POINT THIS EVE AND MEDIUM CONFIDENCE IN IFR. LOW CONFIDENCE IN IFR DURATION. * MEDIUM CONFIDENCE IN WIND DIRECTION AND SPEED. WINDS MAY TURN SHARPLY NEAR OUTFLOW BOUNDARIES FROM SHOWERS THIS AFTERNOON. * LOW CONFIDENCE IN SCT SHRA SAT AFTERNOON. //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...VFR. CHANCE FOR SHOWERS MONDAY EVENING. TUESDAY THROUGH THURSDAY...DRY AND VFR. MTF && .MARINE... 251 AM CDT LOW PRESSURE OVER SOUTHERN NEW YORK WILL LIFT NORTHWARD INTO SOUTHERN QUEBEC TODAY AND TONIGHT BEFORE TURNING NORTHEASTWARD UP THE ST. LAWRENCE VALLEY LATER SATURDAY. A TROUGH EXTENDS NORTHWESTWARD ACROSS LAKE SUPERIOR WITH ANOTHER WEAKER LOW CIRCULATION NEAR SOUTHERN LAKE HURON. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE LAKE TODAY WHILE THE LOW NEAR LAKE HURON PIVOTS EASTWARD DRAGGING A COLD FRONT SOUTHWARD DOWN THE LAKE. WESTERLY WINDS WILL TURN NORTH AND NORTHEAST BEHIND THE FRONT BY EVENING AND LIKELY CONTINUE THROUGH EARLY NEXT WEEK. THE PRESSURE GRADIENT WILL TIGHTEN ACROSS THE LAKE SATURDAY ALLOWING FOR AN INCREASE IN WIND SPEEDS TONIGHT AND SATURDAY BEFORE EASING LATER SUNDAY. WHILE MIXING WILL LIKELY BE MUTED BY THE STRONG MARINE LAYER THE GRADIENT WILL BE RATHER STRONG SO 20-25 KT SPEEDS ARE EXPECTED. THIS WILL SET UP A LONG FETCH DOWN THE LAKE FOR ALLOWING WAVES TO BUILD...LIKELY TO SMALL CRAFT ADVISORY LEVEL STARTING SATURDAY MORNING OR EARLY SATURDAY AFTERNOON WITH SLIGHT IMPROVEMENT POSSIBLE SUNDAY. THE NORTHERLY WINDS LOOK TO CONTINUE THROUGH TUESDAY WHEN WEAK HIGH PRESSURE WILL BE ACROSS THE GREAT LAKES AND MISSISSIPPI VALLEY. THE HIGH WILL THEN SHIFT OFF TO THE EAST ALLOWING SOUTHERLY WINDS TO RETURN. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 PM SATURDAY TO 3 AM MONDAY. IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...9 AM SATURDAY TO 3 AM MONDAY. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
232 PM CDT FRI JUN 28 2013 .MESOSCALE DISCUSSION... 230 PM CDT MONITORING GUSTY STORMS ACROSS NORTH CENTRAL TO NORTHEAST IL. A COUPLE ARCS OF CONVECTION HAVE DEVELOPED ON THE LEADING EDGE OF THE INCOMING SHORT WAVE. THIS LEADING EDGE HAS AN UNSTABLE ATMOSPHERE TO WORK WITH GIVEN SURFACE TEMPERATURES SEVERAL DEGREES ABOVE CONVECTIVE TEMPS PER MORNING SOUNDINGS AND AMDAR DATA. NICE INVERTED-V SHAPE SOUNDINGS ARE PRESENT UP TO 5000-6000 FT WITH ASSOCIATED DOWNDRAFT CAPE ANALYZED BY THE RAP IN EXCESS OF 800 J/KG. THE STORM MOVING ACROSS SOUTHERN KANE NOW HAS PRODUCED A 46 MPH GUST AT DEKALB...AN ESTIMATED 50 MPH GUST AT HINKLEY...AND A MEASURED 52 MPH GUST AT AURORA. THIS IS THE MOST ORGANIZED STORM BUT ANY OF THESE WILL HAVE THE POTENTIAL TO PRODUCE WINDS...AND POSSIBLY SOME SMALL HAIL. WILL CONTINUE WITH SPECIAL WEATHER STATEMENTS ON THESE BUT WOULD NOT BE SURPRISED TO HAVE A BRIEF SEVERE THUNDERSTORM WARNING OR TWO...ESPECIALLY ON THESE LEADING TWO ARCS. MTF && .DISCUSSION... 1135 AM CDT ONLY SOME MINOR TWEAKS TO SHORT TERM FORECAST GRIDS FOR THE REST OF TODAY AND THIS EVENING TO ACCOUNT FOR RECENT AND CURRENT TEMPERATURE...DEW POINT AND CLOUD TRENDS. A SMALL VORT MAX IN THE NW UPPER FLOW DROPPED SE TO SE WI OVERNIGHT PRODUCING SOME MINOR SHOWERS AND AN ISOLATED TS. BUT MID MORNING IT HAD MOVES OUT OF SOUTHERN LAKE MI AND IS CURRENTLY UPPER APPROACHING THE SW SHORE OF LOWER MI AND WILL NOT POSE ANY THREAT OF SHRA OR TS TO THE LOCAL AREA. UPSTREAM...WATER VAPOR SATELLITE LOOPS SHOW ANOTHER SHORT WAVE/VORT MAX HAS BEEN QUICKLY DROPPING SSE FROM E CENTRAL MN TO W CENTRAL WI THIS MORNING. NAM12 AND RUC13 SEEM TO HAVE A DECENT HANDLE ON THIS FEATURE AND TURN IT MORE SE AS IT STARTS TO ENTER THE BROAD UPPER TROUGH FROM THE UPPER MIDWEST E TO THE NEW ENGLAND COAST AND S TO THE MID MS...OH...AND TN VALLEYS...AND THE MID ATLANTIC COAST. EXTRAPOLATION OF RECENT MOVEMENT OF THE WI SHORT WAVE IS IN DECENT AGREEMENT WITH ABOVE MENTIONED MODELS BRINGING THE THE SHORT WAVE TROUGH S OF THE WI BORDER BETWEEN 20 AND 21Z. SIGNIFICANT MID LEVEL COOLING OCCUR ED SINCE YESTERDAY AND WHILE MODELS TEMPERATURE PROFILES SHOW WARMING DURING THE DAY BY 29.00Z THERE IS STILL A DEEP ALBEIT MUCH NARROW AREA OF CAPE OVER THE LOCAL AREA THAN THIS MORNING. STILL...WITH CONVECTIVE TEMPERATURES TO BE REACHED BY NOON EXPECT TO SEE QUICK CU DEVELOPMENT AHEAD OF LARGE AREA OF CLOUDS ADVECTING ACROSS SOUTHERN WI TOWARD NORTHERN IL AND NW IN. AS OF 1125 AM CDT RADAR COMPOSITE LOOP SHOWED ONLY SCATTERED SMALL LIGHT SHOWERS UPSTREAM OF THE LOCAL FORECAST AREA BUT WITH SOME ADDITIONAL HEATING AVAILABLE THROUGH DECREASING ML-CAPE OF 1200 TO 2000 J/KG DEPENDING ON WHICH MODEL OVER THE AREA AND DECENT UVV IN THE LOWER AND MID LEVELS AHEAD OF THE APPROACHING SHORT WAVE TROUGH FEEL THAT ALONG WITH INCREASING CLOUDY COVER TO BROKEN OR NEAR OVERCAST PROBABILITY OF SHOWERS WILL BE INCREASING TO LIKELY DURING THE AFTERNOON...WITH ALSO A SOME THUNDERSTORMS OCCURRING. TRS //PREV DISCUSSION... 339 AM CDT SYNOPSIS...THE LARGE SCALE PATTERN WILL NOT CHANGE MUCH OVER THE NEXT WEEK WITH A LARGE RIDGE OVER THE WESTERN U.S. AND A TROUGH OVER THE EASTERN U.S. STORMS ARE EXPECTED TODAY AND TOMORROW WITH A BRIEF DRY PERIOD EXPECTED EARLY NEXT WEEK. ALSO EXPECTED IS A COOL PERIOD AS NORTH FLOW SETS UP SATURDAY. TODAY AND TONIGHT... THE SURFACE LOW THAT IS CENTERED OVER NEW ENGLAND AND STRETCHES BACK TO LAKE SUPERIOR WILL SINK SOUTH TODAY. IN ADDITION THE UPPER LEVEL JET EXIT WILL ALSO BE SINKING SOUTH THROUGH THE CWA WITH THE LEFT JET EXIT REGION OVERHEAD DURING PRIME HEATING THIS AFTERNOON. LONG SKINNY CAPE OF UP TO 1000 J/KG IS FORECAST AND SHEAR WILL BE MINIMAL AT BEST...10 KT OR SO. THEREFORE EXPECTING SCATTERED STORMS TO SPROUT FIRST ALONG THE IL/WI STATE LINE AROUND NOON AND SCATTERED THUNDERSTORMS SHOULD SPREAD ACROSS THE CWA EARLY THIS AFTERNOON. LATER IN THE AFTERNOON AS THE WAVE COMES THROUGH EXPECTING THE MAIN THUNDERSTORM ACTIVITY TO BE EAST OF A NORTHWEST BOONE COUNTY TO SOUTH CENTRAL IROQUOIS COUNTY LINE. SCATTERED THUNDERSTORMS ARE CERTAINLY POSSIBLE WEST OF THAT LINE AS WELL...BUT THINKING THE STRONGER STORMS AND BETTER COVERAGE WILL BE EAST OF THE LINE. STORMS WILL LIKELY BE PULSEY AND UNORGANIZED AS THERE IS A DECENT AMOUNT OF CAPE BUT NOT ENOUGH SHEAR FOR LONG LIVED ORGANIZED STORMS. THE DIURNAL CONVECTION WILL WIND DOWN AFTER SUNSET WITH SCATTERED SHOWERS OVERNIGHT. ENJOY THE TEMPS TODAY BECAUSE A COOL DOWN IS EXPECTED TOMORROW. HIGHS WILL RANGE FROM AROUND 80 TO THE MID 80S. SATURDAY AND SUNDAY... WINDS TURN NORTH SATURDAY BEHIND THE UPPER LEVEL TROUGH AND MUCH COOLER AIR MOVES INTO THE REGION. THE UPPER LEVEL TROUGH SPLITS WITH THE SOUTHERN LOW BECOMING A CLOSED LOW OVER OHIO LATE SATURDAY NIGHT. YET ANOTHER UPPER LEVEL DISTURBANCE PASSES OVER THE WESTERN HALF OF THE CWA SPARKING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS PRIMARILY WEST OF THE CHICAGO METRO. CAPE WILL BE VERY LOW ON SATURDAY WITH MAYBE A FEW HUNDRED J/KG AVAILABLE. SHEAR WILL BE A BIT MORE FAVORABLE FOR ORGANIZED CONVECTION...BUT THINKING GENERAL THUNDERSTORMS WILL BE THE MAIN SHOW. THE DIURNAL SHOWERS AND THUNDERSTORMS DISSIPATE OVERNIGHT WITH LOW TEMPS FALLING INTO THE UPPER 50S. CLOUD COVER SHOULD REMAIN THICK ENOUGH TO KEEP TEMPS UP A BIT. ON SUNDAY THE UPPER LEVEL TROUGH RETROGRADES A BIT ACROSS THE OHIO RIVER VALLEY AND INSTABILITY ASSOCIATED WITH THE LOW MAY HELP A FEW SHOWERS AND THUNDERSTORMS FORM ON SUNDAY. AREAS ALONG AND SOUTH OF I-80 HAVE THE BEST CHANCE FOR A PASSING SHOWER OR THUNDERSTORM. COVERAGE SHOULD REMAIN SPARSE AND A RAIN OUT IS NOT EXPECTED. ANOTHER DRY NIGHT IS EXPECTED SUNDAY NIGHT. SUNDAY LOOKS A BIT WARMER WITH HIGHS IN THE MID 70S BUT CLOUDS SHOULD THIN SUNDAY NIGHT SO WENT A FEW DEGREES COOLER SUNDAY NIGHT. EXTENDED...MONDAY THROUGH THURSDAY... THE LARGE LOW PRESSURE REMAINS OVER THE EAST COAST WHILE HIGH PRESSURE SINKS SOUTH OUT OF CANADA REACHING THE CWA ON MONDAY. THE UPPER LEVEL TROUGH WILL REMAIN OVERHEAD THROUGHOUT THE EXTENDED WITH DISTURBANCES ROTATING AROUND IT. AS SUCH LEFT PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. TEMPS REMAIN BELOW NORMAL THANKS TO THE UPPER LEVEL LOW AND NORTHERLY SURFACE FLOW. HOWEVER LOOKING LIKE WE MIGHT SEE HIGHS IN THE 80S BY LATE NEXT WEEK. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * PERIODS OF SHRA WITH ISOLATED TSRA AFTER 1930Z. SOME STORMS MAY HAVE GUSTS IN EXCESS OF 40 MPH. * MVFR CIGS ARRIVING THIS EVENING WITH A GOOD CHANCE...ESPECIALLY FOR LATE JUNE...FOR IFR LATER TONIGHT INTO SAT MORNING. * NORTHWEST WINDS TURN NORTH LATE THIS EVENING/OVERNIGHT. * CHANCE FOR SHRA ON SAT AFTERNOON. //DISCUSSION...UPDATED 18Z... BROAD LOW PRESSURE ACROSS THE EASTERN GREAT LAKES AND NEW ENGLAND WILL CONTINUE TO PRESENT NORTHERLY FLOW OVER THE TAF SITES INTO THIS WEEKEND. AN UPPER LEVEL DISTURBANCE MOVING OVERHEAD THIS AFTERNOON INTO THE EARLY EVE WILL PRESENT THE GREATEST COVERAGE OF SHOWERS THROUGH THE NEXT 24 HOURS...WITH ISOLATED TO SCATTERED THUNDER LIKELY. SOME OF THESE INDIVIDUAL STORMS/SHOWERS COULD BE GUSTY GIVEN THE ENVIRONMENT...PUTTING OUT GUST FRONTS THAT WILL EXTEND A WAYS FROM THE ACTUAL RAIN. COVERAGE IS ANTICIPATED TO BE AROUND 70 PERCENT ACROSS CHICAGOLAND FROM 20Z-23Z. COVERAGE WILL BE SLOW TO WANE THROUGH 02Z-04Z THOUGH DIMINISHING INSTABILITY SHOULD ALLOW THE THUNDER THREAT TO DROP QUICKLY THIS EVE. NW WINDS WILL TURN NNE AT SOME POINT TONIGHT...THOUGH CONFIDENCE IN EXACT TIMING REMAINS LOW. WINDS LOOK TO BE NNE TO NE ON SAT...AT LEAST BY LATE MORNING INTO THE AFTERNOON WITH HIGHER CONFIDENCE. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN SHRA WITH MEDIUM CONFIDENCE IN TSRA. HIGH CONFIDENCE IN TIMING WINDOW OF SHRA AND TSRA...ALTHOUGH TIMES OF SHRA/TSRA AT THE AIRFIELD MAY BE BRIEF. * HIGH CONFIDENCE IN MVFR ARRIVING AT SOME POINT THIS EVE AND MEDIUM CONFIDENCE IN IFR. LOW CONFIDENCE IN IFR DURATION. * MEDIUM CONFIDENCE IN WIND DIRECTION AND SPEED. WINDS MAY TURN SHARPLY NEAR OUTFLOW BOUNDARIES FROM SHOWERS THIS AFTERNOON. * LOW CONFIDENCE IN SCT SHRA SAT AFTERNOON. //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...VFR. CHANCE FOR SHOWERS MONDAY EVENING. TUESDAY THROUGH THURSDAY...DRY AND VFR. MTF && .MARINE... 251 AM CDT LOW PRESSURE OVER SOUTHERN NEW YORK WILL LIFT NORTHWARD INTO SOUTHERN QUEBEC TODAY AND TONIGHT BEFORE TURNING NORTHEASTWARD UP THE ST. LAWRENCE VALLEY LATER SATURDAY. A TROUGH EXTENDS NORTHWESTWARD ACROSS LAKE SUPERIOR WITH ANOTHER WEAKER LOW CIRCULATION NEAR SOUTHERN LAKE HURON. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE LAKE TODAY WHILE THE LOW NEAR LAKE HURON PIVOTS EASTWARD DRAGGING A COLD FRONT SOUTHWARD DOWN THE LAKE. WESTERLY WINDS WILL TURN NORTH AND NORTHEAST BEHIND THE FRONT BY EVENING AND LIKELY CONTINUE THROUGH EARLY NEXT WEEK. THE PRESSURE GRADIENT WILL TIGHTEN ACROSS THE LAKE SATURDAY ALLOWING FOR AN INCREASE IN WIND SPEEDS TONIGHT AND SATURDAY BEFORE EASING LATER SUNDAY. WHILE MIXING WILL LIKELY BE MUTED BY THE STRONG MARINE LAYER THE GRADIENT WILL BE RATHER STRONG SO 20-25 KT SPEEDS ARE EXPECTED. THIS WILL SET UP A LONG FETCH DOWN THE LAKE FOR ALLOWING WAVES TO BUILD...LIKELY TO SMALL CRAFT ADVISORY LEVEL STARTING SATURDAY MORNING OR EARLY SATURDAY AFTERNOON WITH SLIGHT IMPROVEMENT POSSIBLE SUNDAY. THE NORTHERLY WINDS LOOK TO CONTINUE THROUGH TUESDAY WHEN WEAK HIGH PRESSURE WILL BE ACROSS THE GREAT LAKES AND MISSISSIPPI VALLEY. THE HIGH WILL THEN SHIFT OFF TO THE EAST ALLOWING SOUTHERLY WINDS TO RETURN. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
107 PM CDT FRI JUN 28 2013 .DISCUSSION... 1135 AM CDT ONLY SOME MINOR TWEAKS TO SHORT TERM FORECAST GRIDS FOR THE REST OF TODAY AND THIS EVENING TO ACCOUNT FOR RECENT AND CURRENT TEMPERATURE...DEW POINT AND CLOUD TRENDS. A SMALL VORT MAX IN THE NW UPPER FLOW DROPPED SE TO SE WI OVERNIGHT PRODUCING SOME MINOR SHOWERS AND AN ISOLATED TS. BUT MID MORNING IT HAD MOVES OUT OF SOUTHERN LAKE MI AND IS CURRENTLY UPPER APPROACHING THE SW SHORE OF LOWER MI AND WILL NOT POSE ANY THREAT OF SHRA OR TS TO THE LOCAL AREA. UPSTREAM...WATER VAPOR SATELLITE LOOPS SHOW ANOTHER SHORT WAVE/VORT MAX HAS BEEN QUICKLY DROPPING SSE FROM E CENTRAL MN TO W CENTRAL WI THIS MORNING. NAM12 AND RUC13 SEEM TO HAVE A DECENT HANDLE ON THIS FEATURE AND TURN IT MORE SE AS IT STARTS TO ENTER THE BROAD UPPER TROUGH FROM THE UPPER MIDWEST E TO THE NEW ENGLAND COAST AND S TO THE MID MS...OH...AND TN VALLEYS...AND THE MID ATLANTIC COAST. EXTRAPOLATION OF RECENT MOVEMENT OF THE WI SHORT WAVE IS IN DECENT AGREEMENT WITH ABOVE MENTIONED MODELS BRINGING THE THE SHORT WAVE TROUGH S OF THE WI BORDER BETWEEN 20 AND 21Z. SIGNIFICANT MID LEVEL COOLING OCCUR ED SINCE YESTERDAY AND WHILE MODELS TEMPERATURE PROFILES SHOW WARMING DURING THE DAY BY 29.00Z THERE IS STILL A DEEP ALBEIT MUCH NARROW AREA OF CAPE OVER THE LOCAL AREA THAN THIS MORNING. STILL...WITH CONVECTIVE TEMPERATURES TO BE REACHED BY NOON EXPECT TO SEE QUICK CU DEVELOPMENT AHEAD OF LARGE AREA OF CLOUDS ADVECTING ACROSS SOUTHERN WI TOWARD NORTHERN IL AND NW IN. AS OF 1125 AM CDT RADAR COMPOSITE LOOP SHOWED ONLY SCATTERED SMALL LIGHT SHOWERS UPSTREAM OF THE LOCAL FORECAST AREA BUT WITH SOME ADDITIONAL HEATING AVAILABLE THROUGH DECREASING ML-CAPE OF 1200 TO 2000 J/KG DEPENDING ON WHICH MODEL OVER THE AREA AND DECENT UVV IN THE LOWER AND MID LEVELS AHEAD OF THE APPROACHING SHORT WAVE TROUGH FEEL THAT ALONG WITH INCREASING CLOUDY COVER TO BROKEN OR NEAR OVERCAST PROBABILITY OF SHOWERS WILL BE INCREASING TO LIKELY DURING THE AFTERNOON...WITH ALSO A SOME THUNDERSTORMS OCCURRING. TRS //PREV DISCUSSION... 339 AM CDT SYNOPSIS...THE LARGE SCALE PATTERN WILL NOT CHANGE MUCH OVER THE NEXT WEEK WITH A LARGE RIDGE OVER THE WESTERN U.S. AND A TROUGH OVER THE EASTERN U.S. STORMS ARE EXPECTED TODAY AND TOMORROW WITH A BRIEF DRY PERIOD EXPECTED EARLY NEXT WEEK. ALSO EXPECTED IS A COOL PERIOD AS NORTH FLOW SETS UP SATURDAY. TODAY AND TONIGHT... THE SURFACE LOW THAT IS CENTERED OVER NEW ENGLAND AND STRETCHES BACK TO LAKE SUPERIOR WILL SINK SOUTH TODAY. IN ADDITION THE UPPER LEVEL JET EXIT WILL ALSO BE SINKING SOUTH THROUGH THE CWA WITH THE LEFT JET EXIT REGION OVERHEAD DURING PRIME HEATING THIS AFTERNOON. LONG SKINNY CAPE OF UP TO 1000 J/KG IS FORECAST AND SHEAR WILL BE MINIMAL AT BEST...10 KT OR SO. THEREFORE EXPECTING SCATTERED STORMS TO SPROUT FIRST ALONG THE IL/WI STATE LINE AROUND NOON AND SCATTERED THUNDERSTORMS SHOULD SPREAD ACROSS THE CWA EARLY THIS AFTERNOON. LATER IN THE AFTERNOON AS THE WAVE COMES THROUGH EXPECTING THE MAIN THUNDERSTORM ACTIVITY TO BE EAST OF A NORTHWEST BOONE COUNTY TO SOUTH CENTRAL IROQUOIS COUNTY LINE. SCATTERED THUNDERSTORMS ARE CERTAINLY POSSIBLE WEST OF THAT LINE AS WELL...BUT THINKING THE STRONGER STORMS AND BETTER COVERAGE WILL BE EAST OF THE LINE. STORMS WILL LIKELY BE PULSEY AND UNORGANIZED AS THERE IS A DECENT AMOUNT OF CAPE BUT NOT ENOUGH SHEAR FOR LONG LIVED ORGANIZED STORMS. THE DIURNAL CONVECTION WILL WIND DOWN AFTER SUNSET WITH SCATTERED SHOWERS OVERNIGHT. ENJOY THE TEMPS TODAY BECAUSE A COOL DOWN IS EXPECTED TOMORROW. HIGHS WILL RANGE FROM AROUND 80 TO THE MID 80S. SATURDAY AND SUNDAY... WINDS TURN NORTH SATURDAY BEHIND THE UPPER LEVEL TROUGH AND MUCH COOLER AIR MOVES INTO THE REGION. THE UPPER LEVEL TROUGH SPLITS WITH THE SOUTHERN LOW BECOMING A CLOSED LOW OVER OHIO LATE SATURDAY NIGHT. YET ANOTHER UPPER LEVEL DISTURBANCE PASSES OVER THE WESTERN HALF OF THE CWA SPARKING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS PRIMARILY WEST OF THE CHICAGO METRO. CAPE WILL BE VERY LOW ON SATURDAY WITH MAYBE A FEW HUNDRED J/KG AVAILABLE. SHEAR WILL BE A BIT MORE FAVORABLE FOR ORGANIZED CONVECTION...BUT THINKING GENERAL THUNDERSTORMS WILL BE THE MAIN SHOW. THE DIURNAL SHOWERS AND THUNDERSTORMS DISSIPATE OVERNIGHT WITH LOW TEMPS FALLING INTO THE UPPER 50S. CLOUD COVER SHOULD REMAIN THICK ENOUGH TO KEEP TEMPS UP A BIT. ON SUNDAY THE UPPER LEVEL TROUGH RETROGRADES A BIT ACROSS THE OHIO RIVER VALLEY AND INSTABILITY ASSOCIATED WITH THE LOW MAY HELP A FEW SHOWERS AND THUNDERSTORMS FORM ON SUNDAY. AREAS ALONG AND SOUTH OF I-80 HAVE THE BEST CHANCE FOR A PASSING SHOWER OR THUNDERSTORM. COVERAGE SHOULD REMAIN SPARSE AND A RAIN OUT IS NOT EXPECTED. ANOTHER DRY NIGHT IS EXPECTED SUNDAY NIGHT. SUNDAY LOOKS A BIT WARMER WITH HIGHS IN THE MID 70S BUT CLOUDS SHOULD THIN SUNDAY NIGHT SO WENT A FEW DEGREES COOLER SUNDAY NIGHT. EXTENDED...MONDAY THROUGH THURSDAY... THE LARGE LOW PRESSURE REMAINS OVER THE EAST COAST WHILE HIGH PRESSURE SINKS SOUTH OUT OF CANADA REACHING THE CWA ON MONDAY. THE UPPER LEVEL TROUGH WILL REMAIN OVERHEAD THROUGHOUT THE EXTENDED WITH DISTURBANCES ROTATING AROUND IT. AS SUCH LEFT PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. TEMPS REMAIN BELOW NORMAL THANKS TO THE UPPER LEVEL LOW AND NORTHERLY SURFACE FLOW. HOWEVER LOOKING LIKE WE MIGHT SEE HIGHS IN THE 80S BY LATE NEXT WEEK. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * PERIODS OF SHRA WITH ISOLATED TSRA AFTER 1930Z. SOME STORMS MAY HAVE GUSTS IN EXCESS OF 40 MPH. * MVFR CIGS ARRIVING THIS EVENING WITH A GOOD CHANCE...ESPECIALLY FOR LATE JUNE...FOR IFR LATER TONIGHT INTO SAT MORNING. * NORTHWEST WINDS TURN NORTH LATE THIS EVENING/OVERNIGHT. * CHANCE FOR SHRA ON SAT AFTERNOON. //DISCUSSION...UPDATED 18Z... BROAD LOW PRESSURE ACROSS THE EASTERN GREAT LAKES AND NEW ENGLAND WILL CONTINUE TO PRESENT NORTHERLY FLOW OVER THE TAF SITES INTO THIS WEEKEND. AN UPPER LEVEL DISTURBANCE MOVING OVERHEAD THIS AFTERNOON INTO THE EARLY EVE WILL PRESENT THE GREATEST COVERAGE OF SHOWERS THROUGH THE NEXT 24 HOURS...WITH ISOLATED TO SCATTERED THUNDER LIKELY. SOME OF THESE INDIVIDUAL STORMS/SHOWERS COULD BE GUSTY GIVEN THE ENVIRONMENT...PUTTING OUT GUST FRONTS THAT WILL EXTEND A WAYS FROM THE ACTUAL RAIN. COVERAGE IS ANTICIPATED TO BE AROUND 70 PERCENT ACROSS CHICAGOLAND FROM 20Z-23Z. COVERAGE WILL BE SLOW TO WANE THROUGH 02Z-04Z THOUGH DIMINISHING INSTABILITY SHOULD ALLOW THE THUNDER THREAT TO DROP QUICKLY THIS EVE. NW WINDS WILL TURN NNE AT SOME POINT TONIGHT...THOUGH CONFIDENCE IN EXACT TIMING REMAINS LOW. WINDS LOOK TO BE NNE TO NE ON SAT...AT LEAST BY LATE MORNING INTO THE AFTERNOON WITH HIGHER CONFIDENCE. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN SHRA WITH MEDIUM CONFIDENCE IN TSRA. HIGH CONFIDENCE IN TIMING WINDOW OF SHRA AND TSRA...ALTHOUGH TIMES OF SHRA/TSRA AT THE AIRFIELD MAY BE BRIEF. * HIGH CONFIDENCE IN MVFR ARRIVING AT SOME POINT THIS EVE AND MEDIUM CONFIDENCE IN IFR. LOW CONFIDENCE IN IFR DURATION. * MEDIUM CONFIDENCE IN WIND DIRECTION AND SPEED. WINDS MAY TURN SHARPLY NEAR OUTFLOW BOUNDARIES FROM SHOWERS THIS AFTERNOON. * LOW CONFIDENCE IN SCT SHRA SAT AFTERNOON. //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...VFR. CHANCE FOR SHOWERS MONDAY EVENING. TUESDAY THROUGH THURSDAY...DRY AND VFR. MTF && .MARINE... 251 AM CDT LOW PRESSURE OVER SOUTHERN NEW YORK WILL LIFT NORTHWARD INTO SOUTHERN QUEBEC TODAY AND TONIGHT BEFORE TURNING NORTHEASTWARD UP THE ST. LAWRENCE VALLEY LATER SATURDAY. A TROUGH EXTENDS NORTHWESTWARD ACROSS LAKE SUPERIOR WITH ANOTHER WEAKER LOW CIRCULATION NEAR SOUTHERN LAKE HURON. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE LAKE TODAY WHILE THE LOW NEAR LAKE HURON PIVOTS EASTWARD DRAGGING A COLD FRONT SOUTHWARD DOWN THE LAKE. WESTERLY WINDS WILL TURN NORTH AND NORTHEAST BEHIND THE FRONT BY EVENING AND LIKELY CONTINUE THROUGH EARLY NEXT WEEK. THE PRESSURE GRADIENT WILL TIGHTEN ACROSS THE LAKE SATURDAY ALLOWING FOR AN INCREASE IN WIND SPEEDS TONIGHT AND SATURDAY BEFORE EASING LATER SUNDAY. WHILE MIXING WILL LIKELY BE MUTED BY THE STRONG MARINE LAYER THE GRADIENT WILL BE RATHER STRONG SO 20-25 KT SPEEDS ARE EXPECTED. THIS WILL SET UP A LONG FETCH DOWN THE LAKE FOR ALLOWING WAVES TO BUILD...LIKELY TO SMALL CRAFT ADVISORY LEVEL STARTING SATURDAY MORNING OR EARLY SATURDAY AFTERNOON WITH SLIGHT IMPROVEMENT POSSIBLE SUNDAY. THE NORTHERLY WINDS LOOK TO CONTINUE THROUGH TUESDAY WHEN WEAK HIGH PRESSURE WILL BE ACROSS THE GREAT LAKES AND MISSISSIPPI VALLEY. THE HIGH WILL THEN SHIFT OFF TO THE EAST ALLOWING SOUTHERLY WINDS TO RETURN. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1135 AM CDT FRI JUN 28 2013 .DISCUSSION... 1135 AM CDT ONLY SOME MINOR TWEAKS TO SHORT TERM FORECAST GRIDS FOR THE REST OF TODAY AND THIS EVENING TO ACCOUNT FOR RECENT AND CURRENT TEMPERATURE...DEW POINT AND CLOUD TRENDS. A SMALL VORT MAX IN THE NW UPPER FLOW DROPPED SE TO SE WI OVERNIGHT PRODUCING SOME MINOR SHOWERS AND AN ISOLATED TS. BUT MID MORNING IT HAD MOVES OUT OF SOUTHERN LAKE MI AND IS CURRENTLY UPPER APPROACHING THE SW SHORE OF LOWER MI AND WILL NOT POSE ANY THREAT OF SHRA OR TS TO THE LOCAL AREA. UPSTREAM...WATER VAPOR SATELLITE LOOPS SHOW ANOTHER SHORT WAVE/VORT MAX HAS BEEN QUICKLY DROPPING SSE FROM E CENTRAL MN TO W CENTRAL WI THIS MORNING. NAM12 AND RUC13 SEEM TO HAVE A DECENT HANDLE ON THIS FEATURE AND TURN IT MORE SE AS IT STARTS TO ENTER THE BROAD UPPER TROUGH FROM THE UPPER MIDWEST E TO THE NEW ENGLAND COAST AND S TO THE MID MS...OH...AND TN VALLEYS...AND THE MID ATLANTIC COAST. EXTRAPOLATION OF RECENT MOVEMENT OF THE WI SHORT WAVE IS IN DECENT AGREEMENT WITH ABOVE MENTIONED MODELS BRINGING THE THE SHORT WAVE TROUGH S OF THE WI BORDER BETWEEN 20 AND 21Z. SIGNIFICANT MID LEVEL COOLING OCCUR ED SINCE YESTERDAY AND WHILE MODELS TEMPERATURE PROFILES SHOW WARMING DURING THE DAY BY 29.00Z THERE IS STILL A DEEP ALBEIT MUCH NARROW AREA OF CAPE OVER THE LOCAL AREA THAN THIS MORNING. STILL...WITH CONVECTIVE TEMPERATURES TO BE REACHED BY NOON EXPECT TO SEE QUICK CU DEVELOPMENT AHEAD OF LARGE AREA OF CLOUDS ADVECTING ACROSS SOUTHERN WI TOWARD NORTHERN IL AND NW IN. AS OF 1125 AM CDT RADAR COMPOSITE LOOP SHOWED ONLY SCATTERED SMALL LIGHT SHOWERS UPSTREAM OF THE LOCAL FORECAST AREA BUT WITH SOME ADDITIONAL HEATING AVAILABLE THROUGH DECREASING ML-CAPE OF 1200 TO 2000 J/KG DEPENDING ON WHICH MODEL OVER THE AREA AND DECENT UVV IN THE LOWER AND MID LEVELS AHEAD OF THE APPROACHING SHORT WAVE TROUGH FEEL THAT ALONG WITH INCREASING CLOUDY COVER TO BROKEN OR NEAR OVERCAST PROBABILITY OF SHOWERS WILL BE INCREASING TO LIKELY DURING THE AFTERNOON...WITH ALSO A SOME THUNDERSTORMS OCCURRING. TRS && .PREV DISCUSSION... 339 AM CDT SYNOPSIS...THE LARGE SCALE PATTERN WILL NOT CHANGE MUCH OVER THE NEXT WEEK WITH A LARGE RIDGE OVER THE WESTERN U.S. AND A TROUGH OVER THE EASTERN U.S. STORMS ARE EXPECTED TODAY AND TOMORROW WITH A BRIEF DRY PERIOD EXPECTED EARLY NEXT WEEK. ALSO EXPECTED IS A COOL PERIOD AS NORTH FLOW SETS UP SATURDAY. TODAY AND TONIGHT... THE SURFACE LOW THAT IS CENTERED OVER NEW ENGLAND AND STRETCHES BACK TO LAKE SUPERIOR WILL SINK SOUTH TODAY. IN ADDITION THE UPPER LEVEL JET EXIT WILL ALSO BE SINKING SOUTH THROUGH THE CWA WITH THE LEFT JET EXIT REGION OVERHEAD DURING PRIME HEATING THIS AFTERNOON. LONG SKINNY CAPE OF UP TO 1000 J/KG IS FORECAST AND SHEAR WILL BE MINIMAL AT BEST...10 KT OR SO. THEREFORE EXPECTING SCATTERED STORMS TO SPROUT FIRST ALONG THE IL/WI STATE LINE AROUND NOON AND SCATTERED THUNDERSTORMS SHOULD SPREAD ACROSS THE CWA EARLY THIS AFTERNOON. LATER IN THE AFTERNOON AS THE WAVE COMES THROUGH EXPECTING THE MAIN THUNDERSTORM ACTIVITY TO BE EAST OF A NORTHWEST BOONE COUNTY TO SOUTH CENTRAL IROQUOIS COUNTY LINE. SCATTERED THUNDERSTORMS ARE CERTAINLY POSSIBLE WEST OF THAT LINE AS WELL...BUT THINKING THE STRONGER STORMS AND BETTER COVERAGE WILL BE EAST OF THE LINE. STORMS WILL LIKELY BE PULSEY AND UNORGANIZED AS THERE IS A DECENT AMOUNT OF CAPE BUT NOT ENOUGH SHEAR FOR LONG LIVED ORGANIZED STORMS. THE DIURNAL CONVECTION WILL WIND DOWN AFTER SUNSET WITH SCATTERED SHOWERS OVERNIGHT. ENJOY THE TEMPS TODAY BECAUSE A COOL DOWN IS EXPECTED TOMORROW. HIGHS WILL RANGE FROM AROUND 80 TO THE MID 80S. SATURDAY AND SUNDAY... WINDS TURN NORTH SATURDAY BEHIND THE UPPER LEVEL TROUGH AND MUCH COOLER AIR MOVES INTO THE REGION. THE UPPER LEVEL TROUGH SPLITS WITH THE SOUTHERN LOW BECOMING A CLOSED LOW OVER OHIO LATE SATURDAY NIGHT. YET ANOTHER UPPER LEVEL DISTURBANCE PASSES OVER THE WESTERN HALF OF THE CWA SPARKING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS PRIMARILY WEST OF THE CHICAGO METRO. CAPE WILL BE VERY LOW ON SATURDAY WITH MAYBE A FEW HUNDRED J/KG AVAILABLE. SHEAR WILL BE A BIT MORE FAVORABLE FOR ORGANIZED CONVECTION...BUT THINKING GENERAL THUNDERSTORMS WILL BE THE MAIN SHOW. THE DIURNAL SHOWERS AND THUNDERSTORMS DISSIPATE OVERNIGHT WITH LOW TEMPS FALLING INTO THE UPPER 50S. CLOUD COVER SHOULD REMAIN THICK ENOUGH TO KEEP TEMPS UP A BIT. ON SUNDAY THE UPPER LEVEL TROUGH RETROGRADES A BIT ACROSS THE OHIO RIVER VALLEY AND INSTABILITY ASSOCIATED WITH THE LOW MAY HELP A FEW SHOWERS AND THUNDERSTORMS FORM ON SUNDAY. AREAS ALONG AND SOUTH OF I-80 HAVE THE BEST CHANCE FOR A PASSING SHOWER OR THUNDERSTORM. COVERAGE SHOULD REMAIN SPARSE AND A RAIN OUT IS NOT EXPECTED. ANOTHER DRY NIGHT IS EXPECTED SUNDAY NIGHT. SUNDAY LOOKS A BIT WARMER WITH HIGHS IN THE MID 70S BUT CLOUDS SHOULD THIN SUNDAY NIGHT SO WENT A FEW DEGREES COOLER SUNDAY NIGHT. EXTENDED...MONDAY THROUGH THURSDAY... THE LARGE LOW PRESSURE REMAINS OVER THE EAST COAST WHILE HIGH PRESSURE SINKS SOUTH OUT OF CANADA REACHING THE CWA ON MONDAY. THE UPPER LEVEL TROUGH WILL REMAIN OVERHEAD THROUGHOUT THE EXTENDED WITH DISTURBANCES ROTATING AROUND IT. AS SUCH LEFT PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST. TEMPS REMAIN BELOW NORMAL THANKS TO THE UPPER LEVEL LOW AND NORTHERLY SURFACE FLOW. HOWEVER LOOKING LIKE WE MIGHT SEE HIGHS IN THE 80S BY LATE NEXT WEEK. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * SCATTERED TO NUMEROUS SHRA/TSRA THIS AFTERNOON. SOME MAY HAVE GUSTS IN EXCESS OF 40 MPH. * MVFR CIGS ARRIVING THIS EVENING WITH A GOOD CHANCE FOR IFR TONIGHT. * NORTHWEST WINDS TURN NORTH LATE THIS EVENING/OVERNIGHT. //DISCUSSION...UPDATED 12Z... MAIN CONCERN TODAY IS SCATTERED SHRA/TSRA EXPECTED TO ARRIVE WITH THE PASSAGE OF AN UPPER LEVEL WAVE. RADAR/SATELLITE DEPICT A WEAK WAVE JUST REACHING SOUTHERN LAKE MICHIGAN FROM THE NORTHWEST AND BRINGING A BATCH OF MID CLOUD COVER AND A FEW LIGHT RAIN SHOWERS. THIS WAVE WILL PASS TO THE EAST OF THE TERMINALS IN THE NEXT FEW HOURS AND SHOULD MAINLY RESULT IN AN INCREASE IN CLOUDS. ATTENTION TURNS TO THE UPPER LOW SPINNING OVER EASTERN LAKE SUPERIOR WITH A TROUGH AXIS ORIENTED TO ITS NORTHWEST WHICH HAS MERGED WITH A WAVE THAT WAS MOVING SOUTHEAST FROM THE CANADIAN PRAIRIES. THIS WAVE WILL REACH THE AREA THIS AFTERNOON AND IS EXPECTED TO PRODUCE SHRA/TSRA ACROSS THE AREA. WILL GO AHEAD AND INCREASE TO TEMPO TSRA FOR A FEW HOURS THIS AFTERNOON BUT THERE COULD BE ACTIVITY NEAR THE TERMINALS FOR MUCH OF THE AFTERNOON SO WILL CARRY A LONGER PERIOD OF VCTS. ACTIVITY WILL WANE WITH SUNSET IF IT IS NOT ALREADY SOUTHEAST OF THE AREA. A COOL FRONTAL BOUNDARY WILL ALSO CROSS THE AREA LATER TODAY WHICH WILL TURN THE GUSTY WEST- NORTHWEST WINDS TO NORTH OR EVEN NORTH-NORTHEAST OVERNIGHT. A MUCH COOLER AIRMASS WILL SPREAD IN WITH MVFR CIGS LIKELY TO ACCOMPANY IT WITH A DECENT CHANCE FOR IFR. SATELLITE DOES SHOW AN EXTENSIVE AREA OF STRATUS ACROSS THE ARROWHEAD OF MINNESOTA AND MUCH OF WESTERN ONTARIO WITH SURFACE OBS SHOWING EXTENSIVE IFR. HAVE LOWERED CIGS TO IFR FOR A PERIOD TONIGHT AND AM THINKING CIGS WILL IMPROVE TO MVFR SATURDAY MORNING. //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN SCATTERED SHRA/TSRA DEVELOPMENT AND MEDIUM CONFIDENCE IN TIMING. LOW CONFIDENCE ON GUSTY STORMS OCCURRING RIGHT OVER THE AIRFIELD. * MEDIUM-HIGH CONFIDENCE IN MVFR CIGS ARRIVING SOME TIME THIS EVENING AND CONTINUING INTO SATURDAY MORNING. MEDIUM CONFIDENCE IN IFR DEVELOPING...LOW-MEDIUM CONFIDENCE IN TIMING. * HIGH CONFIDENCE IN WIND TRENDS THROUGH THE AFTERNOON...MEDIUM CONFIDENCE FROM THIS EVENING ON...MEDIUM CONFIDENCE IN SPEEDS/GUSTS. //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...VFR. CHANCE FOR SHOWERS MONDAY EVENING. TUESDAY THROUGH THURSDAY...DRY AND VFR. MDB/MTF && .MARINE... 251 AM CDT LOW PRESSURE OVER SOUTHERN NEW YORK WILL LIFT NORTHWARD INTO SOUTHERN QUEBEC TODAY AND TONIGHT BEFORE TURNING NORTHEASTWARD UP THE ST. LAWRENCE VALLEY LATER SATURDAY. A TROUGH EXTENDS NORTHWESTWARD ACROSS LAKE SUPERIOR WITH ANOTHER WEAKER LOW CIRCULATION NEAR SOUTHERN LAKE HURON. AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE LAKE TODAY WHILE THE LOW NEAR LAKE HURON PIVOTS EASTWARD DRAGGING A COLD FRONT SOUTHWARD DOWN THE LAKE. WESTERLY WINDS WILL TURN NORTH AND NORTHEAST BEHIND THE FRONT BY EVENING AND LIKELY CONTINUE THROUGH EARLY NEXT WEEK. THE PRESSURE GRADIENT WILL TIGHTEN ACROSS THE LAKE SATURDAY ALLOWING FOR AN INCREASE IN WIND SPEEDS TONIGHT AND SATURDAY BEFORE EASING LATER SUNDAY. WHILE MIXING WILL LIKELY BE MUTED BY THE STRONG MARINE LAYER THE GRADIENT WILL BE RATHER STRONG SO 20-25 KT SPEEDS ARE EXPECTED. THIS WILL SET UP A LONG FETCH DOWN THE LAKE FOR ALLOWING WAVES TO BUILD...LIKELY TO SMALL CRAFT ADVISORY LEVEL STARTING SATURDAY MORNING OR EARLY SATURDAY AFTERNOON WITH SLIGHT IMPROVEMENT POSSIBLE SUNDAY. THE NORTHERLY WINDS LOOK TO CONTINUE THROUGH TUESDAY WHEN WEAK HIGH PRESSURE WILL BE ACROSS THE GREAT LAKES AND MISSISSIPPI VALLEY. THE HIGH WILL THEN SHIFT OFF TO THE EAST ALLOWING SOUTHERLY WINDS TO RETURN. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
101 PM CDT FRI JUN 28 2013 .UPDATE... ISSUED AT 1249 PM CDT FRI JUN 28 2013 CONVECTIVE CLOUDS HAVE DEVELOPED IN THE PAST 2 HRS AND CONVECTIVE CELLS HAVE DEVELOPED IN THE PAST 45 MINUTES. CONVECTIVE TRENDS WILL BE ON THE INCREASE THROUGH THE AFTERNOON WITH ISOLATED TO SCATTERED SHOWERS AND A FEW THUNDERSTORMS. CONVECTION DEVELOPING SOUTH OF I-80 IS MORE QUESTIONABLE. HOWEVER...IF A REASONABLY STRONG CONVECTIVE CELL CAN DEVELOP THE POTENTIAL IS THERE FOR WINDS GUSTING TO 40 MPH IN THE DOWNDRAFTS. BASED ON CURRENT TEMPERATURES...HAVE RAISED MAX TEMPERATURES SLIGHTLY. ..08.. UPDATE ISSUED AT 1006 AM CDT FRI JUN 28 2013 BASED ON DATA THROUGH 15Z...THERMALS SHOULD BEGIN DEVELOPING WITHIN THE HOUR WITH DIURNAL CU BY MID DAY. AS SUCH THE REMAINDER OF THE MORNING WILL REMAIN DRY ACROSS THE AREA. RAP TRENDS INDICATE THE CONVECTIVE TEMPERATURE WILL SLOWLY DROP DURING THE DAY WHICH WHEN COMBINED WITH THE APPROACHING VORT MAX SHOULD INITIATE CONVECTION DURING THE AFTERNOON. CONVECTION IS EXPECTED TO BE IN THE FORM OF SHOWERS WITH SOME THUNDERSTORMS. CONVECTION WILL CONTINUE INTO THE EVENING WITH THE THUNDERSTORMS DISSIPATING WITH SUNSET. HOWEVER...THE PROXIMITY OF THE COOL POOL ALOFT AND UPPER LOW SHOULD KEEP SHOWERS GOING WELL INTO THE EVENING AND OVERNIGHT HOURS WITH DECREASING COVERAGE. ..08.. && .SYNOPSIS... ISSUED AT 300 AM CDT FRI JUN 28 2013 WATER VAPOR LOOPS SHOWED A BROAD UPPER TROUGH ACROSS THE GREAT LAKES WITH A CLOSED LOW ON THE NORTHERN TIP OF LAKE SUPERIOR. A STRONG SHORT WAVE/VORT MAX WAS LOCATED IN NORTHEAST MN. A FEW SHOWERS WERE NOTED IN CENTRAL WI. OTHERWISE CLEAR SKIES WERE ACROSS THE DVN CWA WHILE A LARGE MCS WAS COVERING SOUTHERN MO AHEAD OF A COLD FRONT. CURRENT TEMPERATURES IN THE DVN CWA RANGED FROM THE MID 60S TO LOWER 70S WITH DEWPOINTS IN THE UPPER 50S NW TO UPPER 60S SE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 300 AM CDT FRI JUN 28 2013 FORECAST FOCUS ON SHOWER CHANCES...CLOUD TRENDS AND TEMPERATURES. TODAY...OPERATIONAL MODELS SLIDE THE GREAT LAKES TROUGH SOUTHWARD INTO OUR REGION WITH THE RAP DEPICTING A STRONG VORT MAX MOVING FROM NORTHEAST MN INTO NORTHERN IL THIS AFTERNOON. WITH COOLING TEMPERATURES ALOFT COMBINED WITH DAYTIME HEATING INSTABILITY WILL INCREASE. HAVE CONFINED POPS TO THIS AFTERNOON AND ALSO ACROSS OUR NORTHEAST HALF CWA CLOSER TO THE TRACK OF THE VORT MAX. THE HRRR MESO MODEL DEPICTS THE POPCORN DESCRIPTION OF THE SCATTERED INSTABILITY SHOWERS (AND A FEW THUNDERSTORMS) QUITE WELL. THERE WILL BE PLENTY OF SUNSHINE FOR MOST OF THIS MORNING BUT CLOUDS WILL DEVELOP/FILL AS THE CONVECTIVE TEMPERATURE IS REACHED. MAXIMUM TEMPERATURES WILL RANGE FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH BUT HUMIDITY LEVELS WILL BE THANKFULLY LOWER COMPARED TO THE LAST FEW DAYS. TONIGHT...WITH THE UPPER TROUGH OVER THE AREA WILL CONTINUE WITH CHANCE POPS AS SKIES WILL BE MOSTLY CLOUDY OR BECOME MOSTLY CLOUDY. HOWEVER...WITH THE LOSS OF HEATING/BETTER INSTABILITY THE COVERAGE OF SHOWERS WILL DECREASE OVERNIGHT. MINIMUM TEMPERATURES SHOULD BE IN THE LOWER 60S AT MOST LOCATIONS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 300 AM CDT FRI JUN 28 2013 A DIGGING UPPER TROF OVER THE EASTERN U.S IS FORECAST TO CLOSE OFF OVER THE OHIO VALLEY BY LATE IN THE WEEKEND. THEN...MODELS ARE IN AGREEMENT THAT THE CLOSED LOW WILL RETROGRADE INTO THE MID MISSISSIPPI VALLEY EARLY IN THE WEEK AND REMAIN THERE...THEN GRADUALLY FILLING DURING THE LATTER HALF OF THE WEEK. THIS PATTERN WILL SUPPORT BELOW NORMAL TEMPERATURES THROUGH THE FORECAST PERIOD WITH HIGHS GENERALLY IN THE 70S TO AROUND 80 AND LOWS...ESPECIALLY EARLY IN THE WEEK...IN THE 50S. MOST DAYS WILL HAVE AT LEAST A LOW THREAT OF RAIN. HOWEVER...AS STATED IN THE PREVIOUS DISCUSSION...THE RAIN THREAT WILL BE LIMITED TO JUST A FEW HOURS EACH DAY. THE BETTER CHANCE OF RAIN DURING THE PERIOD WILL BE SATURDAY AS A SERIES OF S/WS DROP INTO THE DEVELOPING TROF TO OUR EAST. THE BETTER UPPER FORCING APPEARS TO BE JUST EAST OF THE FORECAST AREA...SO KEPT THE HIGHER CHANCE AND LIKELY POPS NEAR AND EAST OF THE MISSISSIPPI RIVER. THE RAIN THREAT WILL DIMINISH SATURDAY NIGHT AND SUNDAY AS DRIER LOW LEVEL AIR FILTERS IN FROM THE NORTH. THE DRY WEATHER SHOULD LAST THROUGH MONDAY THEN A LOW RAIN THREAT RETURNS MONDAY NIGHT THROUGH THE END OF THE WEEK AS THE UPPER LOW BACKS INTO THE REGION FROM THE EAST. THIS WILL SUPPORT MAINLY AFTERNOON ISOLATED TO SCATTERED SHOWERS OR THUNDERSTORMS. SINCE ANY SHRA/TSRA ACTIVITY WILL PROBABLY BE TIED TO AFTERNOON HEATING...HAVE LIMITED THE POPS TO THE DAYTIME HOURS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1249 PM CDT FRI JUN 28 2013 CONVECTION HAS DEVELOPED ABOUT AN HOUR AHEAD OF SCHEDULE WITH SOME SHRA ALONG THE WISCONSIN/ILLINOIS BORDER. VFR WX IS EXPECTED THROUGH 06Z/29 WITH VCSH OR VCTS POSSIBLE AT KCID/KMLI. KDBQ HAS THE BETTER CHANCE AT SEEING A SHRA OR TSRA. OVERALL INSTABILITY IS LIMITED SO THE CHANCES OF A TSRA HITTING A TAF SITE IS LOW. AFT 06Z/29 CIGS WILL SLOWLY LOWER WITH MVFR CONDITIONS DVLPG AT KDBQ BY SUNRISE AND KCID/KMLI AFT 12Z/29. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...DLF AVIATION...08
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
148 PM EDT FRI JUN 28 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 328 AM EDT FRI JUN 28 2013 CONDITIONS TODAY WILL BE FAIRLY SIMILAR TO WHAT HAPPENED DURING THE DAY ON THURSDAY. SCATTERED SHOWERS AND STORMS WILL BEGIN TO DEVELOP LATE THIS MORNING AND CONTINUE INTO THE EARLY EVENING HOURS. THE BEST CHANCE FOR RAINFALL WILL OCCUR AWAY FROM LAKE MICHIGAN. PERIODS OF SUNSHINE CAN BE EXPECTED IN BETWEEN SHOWERS THAT OCCUR. LESS IN THE WAY OF RAINFALL IS EXPECTED ON SATURDAY...ALTHOUGH THE CHANCE WILL STILL EXIST SATURDAY AFTERNOON AND EVENING. MOST LOCATIONS SHOULD STAY DRY ON SUNDAY WITH MILD TEMPERATURES WELL INTO THE 70S EXPECTED FOR HIGHS. && .UPDATE... ISSUED AT 740 AM EDT FRI JUN 28 2013 I UPDATED THE ZONES TO REFLECT THE AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NOW MOVING TOWARD MOP. THIS AREA SHOULD BE EAST OF THE CWA BY 10 AM. RAP SOUNDINGS SHOW A MOIST LAYER BETWEEN 800 AND 600 MB BEING THE KICK-0FF FOR THESE SHOWERS WITH IN COMBINATION WITH THE EDGE OF THE UPPER COLD POOL MOVING IN. THE NEXT UPSTREAM SHORTWAVE WILL MOVE INTO THE AREA BY EARLY AFTERNOON AND THE COMBINATION OF THAT THE COMBINED LAKE BREEZES FROM LAKE HURON AND LAKE MICHIGAN SHOULD KEEP THE SHOWERS AND THUNDERSTORMS MOSTLY EAST OF GRAND RAPIDS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 328 AM EDT FRI JUN 28 2013 THE MAIN FOCUS OF THE FORECAST THROUGH THE WEEKEND REMAINS CONVECTIVE TRENDS WITH THE UPPER LOW PARKED OVER THE REGION. THE GENERAL TREND OF THE FCST REMAINS MAINLY UNCHANGED. IT APPEARS THAT WE WILL HAVE SIMILAR CONDITIONS DURING THE DAY TODAY AS COMPARED TO YESTERDAY REGARDING CONVECTION POTENTIAL. CONVECTIVE DEVELOPMENT LOOKS LIKE IT WILL ONCE AGAIN BEGIN TO FIRE LATE IN THE MORNING HOURS ACROSS THE NE CORNER OF THE CWFA. THIS IS DUE TO SFC CONVERGENCE MAXIMIZED IN THAT LOCATION RESULTING FROM A SFC TROUGH THIS IS DROPPING SOUTH THROUGH THE AREA. THE SFC TROUGH IS SUPPORTED BY A LOBE OF THE NEWLY FORMED UPPER LOW DROPPING SOUTH. THE SFC CONVERGENCE/UPPER WAVE WILL BE ACTING ON ML CAPES OF 1000+ J/KG BY 18Z THIS AFTERNOON. IN ADDITION...A SOMEWHAT WRLY COMPONENT TO THE WIND WILL CONVERGE WITH A DEVELOPING LAKE BREEZE FROM LAKE HURON/SAGINAW BAY TO ONLY HELP THE CAUSE. SEVERE WEATHER IS NOT EXPECTED AS THE DEEP LAYER SHEAR IS ABOUT NIL WITH THE UPPER LOW ALMOST DIRECTLY OVER THE AREA. WE CAN EXPECT SOME PULSE TYPE STORMS WITH SOME POSSIBLE HAIL AS THE FREEZING LEVELS COME DOWN TO AROUND 11K FT OR SO. WE CAN NOT RULE OUT A DRY MICROBURST OF SOME SUB-SEVERE WINDS. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE WITH THE SLOW MOVEMENT OF ANY STORMS. THE LAKESHORE WILL HAVE THE LEAST CHC OF STORMS DUE TO THE STABILIZING EFFECTS OF LAKE MICHIGAN. WE CAN NOT RULE OUT SOMETHING SURVIVING THE TRIP FROM WISCONSIN...BUT THIS IS NOT LIKELY. THE LOBE OF THE UPPER LOW WILL ALMOST BE THROUGH THE CWFA FIRST THING ON SAT MORNING AT 12Z. IT WILL DROP SOUTH BY AFTERNOON LEAVING SOME SHORT WAVE RIDGING IN THE WAKE OVER THE CWFA. THIS COMBINED WITH SOME DRIER AIR ADVECTING IN FROM THE NE WILL LIMIT ML CAPES FROM GETTING MUCH HIGHER THAN 500 J/KG DURING THE DAY ON SAT. THE FLOW WILL BECOME NE WHICH WILL TAKE OUT THE STABILIZING EFFECTS FROM LAKE MICHIGAN. IN FACT...SOME OF THE BEST CHCS OF SHOWERS/STORMS ON SAT MIGHT BE ALONG THE LAKE BREEZE WITH THE W AND NE WINDS CONVERGING AT A GOOD ANGLE. COVERAGE AND INTENSITY SHOULD BE LOWER THAN TODAY. SEVERE WEATHER IS ONCE AGAIN NOT EXPECTED WITH SHEAR VALUES BELOW 20 KNOTS. THE THREAT FOR SHOWERS AND STORMS GOES DOWN EVEN MORE ON SUN AS EVEN DRIER AIR ADVECTS IN AT THE LOWER LEVELS. ML CAPES ARE FCST TO ONLY MAKE IT TO AROUND 200 J/KG AT BEST. THIS WILL KEEP A LID ON MOST CONVECTION THAT TRIES TO DEVELOP...EXCEPT MAYBE RIGHT ALONG THE SRN BORDER CLOSER TO THE MID LEVEL COLD POOL. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 328 AM EDT FRI JUN 28 2013 IT WOULD SEEM COOLER THAN NORMAL TEMPERATURES AND AFTERNOON AND EVENING CONVECTION WILL BE THE PRIMARY WEATHER FEATURE THROUGH THIS MOST OF THE COMING WEEK. OVERALL THERE IS GOOD MODEL AGREEMENT WITH BOTH RUN TO RUN AND MODEL TO MODEL OVER CONUS THROUGH THIS COMING WEEK. HOWEVER BY WEDNESDAY THERE IS A CURIOUS DIFFERENCE OVER EASTERN CANADA BY BETWEEN THE ECMWF AND THE GFS IN THAT THE ECMWF IS MUCH STRONGER AND DEEPER WITH SYSTEM THAT DIVES SOUTH SOUTHEAST INTO QUEBEC. THIS WOULD SUGGEST A MUCH STRONGER COLD FRONT IS HEADING SOUTH TOWARD THE NORTHERN BOARDER STATES LATE IN THE WEEK THAN SHOWN ON THE GFS. HOWEVER FOR THIS FORECAST TIME PERIOD THIS IS MORE OF A CURIOSITY THAN SOMETHING WE HAVE TO WATCH CLOSELY. THE MORE SIGNIFICANT ISSUE IS WE HAVE SPLIT FLOW OVER NORTH AMERICA WITH THE NORTHERN BRANCH NEAR 70N AND THE SOUTHERN BRANCH CLIMBING OVER THE WESTERN RIDGE NEAR 115W INTO SOUTHERN BRITISH COLUMBIA AND MANITOBA... THEN DIVING SOUTHEAST TO NEAR THE GULF COAST WEST OF MISSOURI RIVER AND THEN HEADING BACK NORTH TO NEW ENGLAND ALONG THE EAST COAST. THIS DIP IN THE JET STREAM IS ANOMALOUS FOR THIS TIME OF YEAR IS THE RESULT OF AN UPPER LOW THAT SOUTHERN GREAT LAKES THAT SLOWLY RETROGRADES WEST OF THE MISSISSIPPI RIVER BY WEDNESDAY AS SHORTWAVE ENERGY FROM THE SOUTHERN BRANCH DIVES INTO THE WESTERN SIDE OF THE LONG WAVE TROUGH. WHAT THIS DOES IS TO KEEP SOUTHWEST MICHIGAN IN OR NEAR CLOSED UPPER LOW THROUGH MOST OF THE COMING WEEK. IN SUNDAY NIGHT TO MONDAY PERIOD THE UPPER LOW IS FAR ENOUGH SOUTH AND EAST OF OUR AREA SO AS TO ALLOW FOR SOME SURFACE RIDGING AND NORTHEAST SURFACE WINDS BRINGING IN DRY SURFACE AIR. SO THAT IS A TIME WHEN THE PRECIPITATION THREAT WOULD BE LOWEST. BY TUESDAY AND WEDNESDAY AS THE SYSTEM REGRADES... THE SOUTHERLY FLOW ALOFT ON THE EAST SIDE OF THE SYSTEM BRINGS MOISTURE BACK INTO THE REGION WITH DEEP INSTABILITY THAT WILL LEAD TO LARGELY AFTERNOON AND EVENING THUNDERSTORMS. THE SHEAR REMAINS LOW SO THE SEVERE STORM THREAT IS LOW. BY JULY 4TH THE ECMWF SUGGEST UPPER RIDGING TRYING TO BUILD IN WHILE THE GFS KEEP UPPER TROUGH OVER THE AREA. BOTH MODELS BUILD IN AN UPPER RIDGE BY FRIDAY SO BY THEN IT SHOULD DRY OUT AND WARM UP SOME. THE BOTTOM LINE IS THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS IS TUE AND WEDNESDAY... THE DRIEST WEATHER SHOULD BE MONDAY AND FRIDAY. TEMPERATURES WILL RUN BELOW NORMAL THROUGH FRIDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 148 PM EDT FRI JUN 28 2013 CURRENTLY HAVE VFR CONDITIONS AT ALL TAF SITES WITH THUNDERSTORMS NORTH OF LANSING AND EAST OF THE FORECAST AREA. EXPECTING SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP OR MOVE ACROSS MOST OF THE AREA THIS AFTERNOON AND EVENING. THUNDER MAY BE LACKING IN THE STABLE AIR IN THE SHADOW OF LAKE MICHIGAN... SO HAVE NO THUNDER IN THE WESTERN TAFS. THE SCATTERED NATURE OF THE STORMS SHOULD LIMIT IMPACT AT TERMINAL FORECAST LOCATIONS AND WILL KEEP VICINITY WORDING. FOG AND LOW CLOUDS LOOKING POSSIBLE AGAIN TONIGHT WITH IFR VISIBILITIES AND MVFR/IFR CEILINGS. THIS SHOULD BURN OFF BY MID MORNING SATURDAY. CONVECTION IS POSSIBLE AGAIN ON SATURDAY... BUT THE INTENSITY AND COVERAGE SHOULD BE REDUCED. && .MARINE... ISSUED AT 328 AM EDT FRI JUN 28 2013 NO MARINE HEADLINES ARE EXPECTED THROUGH THE WEEKEND. WE WILL SEE WINDS GENERALLY RUNNING AROUND 10 TO 15 KNOTS EACH DAY FROM TODAY THROUGH SUNDAY. THIS WILL PRODUCE WAVES OF GENERALLY 1 TO LOCALLY 3 FEET WITH THE HIGHEST WAVES EXPECTED SOUTH DUE TO THE NRLY FETCH. && .HYDROLOGY... ISSUED AT 328 AM EDT FRI JUN 28 2013 NO WIDESPREAD HYDROLOGY HEADLINES EXPECTED THROUGH EARLY NEXT WEEK. WE WILL HAVE TO WATCH FOR SOME LOCALLY HEAVY RAINS FOR TODAY... ALTHOUGH THE THREAT IS A LITTLE LOWER COMPARED TO THU. WE WILL SEE DIURNAL SHOWERS AND STORMS DEVELOP ONCE AGAIN WITH VERY SLOW MOVEMENT EXPECTED DUE TO THE LACK OF WIND IN THE CLOUD LAYER. PRECIPITABLE WATER HAS DROPPED A LITTLE AS THE BEST MOISTURE AXIS HAS MOVED AWAY AND DRIER AIR IS SLOWLY FILTERING IN. SOME FLOOD ADVISORIES WILL BE POSSIBLE WHERE CONVECTION SITS FOR LONGER PERIOD OF TIMES. THE THREAT WILL BECOME MUCH LOWER FOR THE REMAINDER OF THE WEEKEND. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...WDM AVIATION...63 HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
240 PM EDT FRI JUN 28 2013 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL REMAIN OVER THE REGION THROUGH THE WEEKEND. THIS SYSTEM WILL PRODUCE SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD WITH THE MOST WIDESPREAD COVERAGE OCCURRING DURING THE DAYLIGHT HOURS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED AT 1145 AM... SURFACE LOW PRESSURE DOWN TO 996 MB OVER NORTHEAST NY MOVING NORTHEAST. MAIN CONCERN OVER THE NEXT SEVERAL HOURS WILL BE FOR POTENTIAL FOR SHOWERS AND THUNDERSTORMS PRODUCING ISOLATED FLASH FLOODING THIS AFTERNOON ALONG WITH A SEVERE THREAT. SATELLITE LOOPS INDICATE THAT PARTIAL CLEARING IS DEVELOPING ACROSS MUCH OF PA THIS MORNING WITH CLOUDY SKIES CONTINUING ACROSS NY STATE. 12Z BUF SOUNDING SHOWS A BIT OF A WARM LAYER AT 700 MB AND ANOTHER WEAK WARM LAYER UP AROUND 500 MB... SO OVERALL MID-LEVEL LAPSE RATES ARE NOT STEEP. HOWEVER MID-LEVEL WINDS ARE RATHER STRONG WITH 40 KTS SHOWN FROM 700 TO 500 MB. SFC DEW POINTS REMAIN IN THE MID 60S WITH A WEAK SURFACE TROUGH MOVING IN FROM THE WEST. KEY FOR STRONG THUNDERSTORM DEVELOPMENT THIS AFTERNOON WILL BE AMOUNT OF SUNSHINE AND DESTABILIZATION THAT MIGHT OCCUR. LATEST 12Z NAM IS STILL NOT VERY IMPRESSED WITH THE INSTABILITY INDICATING CAPES OF 500 J/KG OR LESS. HOWEVER THE LATEST RAP AND LAST NIGHTS GFS SHOW MORE INSTABILITY WITH CAPES UP NEAR OR JUST OVER 1000 J/KG FROM THE SOUTHERN TIER OF NY SOUTH INTO PA. GIVEN THAT CLEARING IS ALREADY OCCURRING ACROSS MUCH OF PA SUSPECT THAT CAPES PROBABLY WILL AT LEAST APPROACH 1000 J/KG ACROSS NE PA THIS AFTERNOON... AND SOME STRONG THUNDERSTORMS WILL PROBABLY DEVELOP. FARTHER NORTH CLEARING IS LESS CERTAIN SO EXPECTING SHOWERS WITH ISOLATED THUNDER. GIVEN MODERATELY MOIST ATMOSPHERE ANY STORM COULD PRODUCE A QUICK INCH OF RAIN WHICH WOULD BE ENOUGH TO CAUSE ISOLATED FLASH FLOODING... SO AM PLANNING ON EXTENDING THE WATCH INTO EARLY THIS EVENING. ISOLATED SEVERE STORMS ALSO APPEAR TO BE POSSIBLE THIS AFTERNOON ESPECIALLY IN NORTHEAST PA WHERE HEATING WILL INCREASE THE INSTABILTY. PREVIOUS DISCUSSION BELOW. 630 AM UPDATE...MODERATE TO HEAVY RAIN NOW CONFINED TO NORTHERN ONEIDA COUNTY AND THIS WILL LIFT NORTH OF THE AREA BY 8 AM. NEXT BATCH OF SHOWERS/THUNDERSTORMS ASSOCIATED WITH FRONT END OF UPPER LEVEL LOW NOW MOVING INTO WESTERN NEW YORK. THIS WILL BEGIN SPREADING ACROSS WRN PTN OF FA BY MID MORNING. ONLY MINOR ADJUSTMENTS NEEDED TO POP GRIDS. AT 445 AM...SFC LOW PRES WAS LIFTING NORTH THROUGH EASTERN NEW YORK WITH LOCAL RADARS SHOWING MODERATE TO HEAVY RAINFALL ACROSS THE WESTERN MOHAWK VALLEY AND THE NORTHERN SUSQUEHANNA REGION. THE HEAVY PRECIP ON THE BACK SIDE OF THIS LOW WILL GRADUALLY LIFT NORTH OF THE REGION BY MID MORNING. FLASH FLOOD WARNINGS ARE CURRENTLY IN EFFECT FOR MUCH OF THIS AREA. FOR TODAY, UPPER LEVEL LOW OVER THE NRN GREAT LAKES WILL DROP SOUTHEAST INTO THE EASTERN LAKES. MID LEVEL SHORT WAVES ROTATING AROUND THE FEATURE WILL GENERATE MORE WIDESPREAD SHOWERS AND THUNDERSTORMS FROM LATE THIS MORNING THROUGH THE AFTERNOON. ATMOSPHERE REMAINS VERY MOIST WITH PWATS AROUND 1.50-1.75 INCHES, THEREFORE ANY CONVECTION WILL HAVE THE POTENTIAL FOR TORRENTIAL DOWNPOURS. MODEL SOUNDINGS INDICATE CAPE VALUES OF 500-1000 J/KG WHICH WILL ENHANCE CONVECTIVE ACTIVITY UNDER THE UPPER LEVEL FEATURE. WILL CONTINUE WITH FLASH FLOOD WATCH THROUGH THIS AFTERNOON DUE TO ADDITIONAL CONVECTIVE RAINFALL FALLING ON SATURATED SOILS ESPECIALLY OVER CENTRAL NEW YORK EAST OF INTERSTATE 81 AND NORTHEAST PENNSYLVANIA. THERE IS THE POTENTIAL THAT A FEW STORMS COULD BECOME SEVERE BUT ONE AGAIN LAPSE RATES, CAPE VALUES AND MID LEVEL WIND FIELDS ARE VERY MARGINAL. IF SVR CONVECTION DOES OCCUR IT WOULD MOST LIKELY BE OVER THE SOUTHERN CATSKILLS AND POCONOS. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... TONIGHT THROUGH SUNDAY NIGHT...H5 UPPER LEVEL TROF WILL REMAIN JUST WEST OF FA THROUGH SUNDAY NIGHT WITH AIRMASS REMAINING FAIRLY MOIST. CONVECTIVE ACTIVITY WILL PERSIST THROUGH THE PERIOD WITH THE MOST WIDESPREAD ACTIVITY OCCURRING DURING THE DAYLIGHT HOURS ENHANCED BY DIURNAL HEATING. AIRMASS BECOMES EVEN MORE MOISTURE LADEN SUNDAY/SUNDAY NIGHT AS FULL LATITUDE UPPER LEVEL TROF BEGINS TO TAP MORE GULF MOISTURE. A VERY WET PERIOD AHEAD WITH THE CONTINUED POTENTIAL FOR LOCALIZED HEAVY RAINS. MAX TEMPS WILL GENERALLY RANGE FROM THE MID 70S INTO THE LOW 80S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... 2 PM FRI UPDATE... FOLLOWED WPC GUIDANCE. TEMPERATURES AND POPS ABOVE NORMAL. EURO AND GFS SIMILAR WITH A HIGH AMPLITUDE STAGNANT PATTERN FOR THE CONUS. DEEP TROF OVER THE OHIO VALLEY WILL PUT THE AREA IN A MOIST AND WARM SW FLOW FOR MOST OF THE PERIOD. STALLED COASTAL FRONT WITH LIKELY POPS IN THE SE MON NGT TO TUE THEN CHC POPS EVERY DAY AFTER THAT. WITH DAILY DIURNAL SHOWERS HIGH TEMPERATURES SHOULD ONLY MAKE THE LOWER 80S. THIS NEARLY STATIONARY TROF UNUSUAL FOR JULY. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... 130 PM EDT UPDATE... ANOTHER CHALLENGING FORECAST FOR TODAY. TAF SITES HAVE MOSTLY IMPROVED TO VFR. THE EXCEPTION IS KITH. WITH A LIGHT NW FLOW OFF OF LAKE CAYUGA THEY HAVE HAD MOSTLY IFR CIGS AND MVFR VSBYS. THIS SHOULD IMPROVE TO MVFR BY 20Z. ELSEWHERE VFR WITH POSSIBLE MVFR CIGS IN SHOWERS. IN ANY HEAVY RAIN SHOWERS VSBYS COULD FALL TO MVFR. TONIGHT CLOUDS WILL REMAIN. KAVP SHOULD REMAIN VFR. IN NY VFR CONDITIONS WILL FALL TO MVFR AROUND 6Z AND IFR AROUND 9Z. IMPROVEMENT BACK TO VFR BY 14Z. THIS AFTN SW TO NW WINDS AT 5 TO 10 KTS BECOMING LIGHT AND VARIABLE TONIGHT. SW WINDS AT 5 TO 10 KTS SATURDAY. OUTLOOK...SAT THROUGH TUE... SAT THROUGH TUE... OCNL RESTRICTIONS ARE LIKELY EACH DAY...WITH SHRA/TSRA IN THE VICINITY. THE MOST PERSISTENT RESTRICTIONS MAY COME BY MON/MON NGT. && .HYDROLOGY... RECORD RIVER FLOODING OCCURRING AT ONEIDA ON ONEIDA CREEK. RIVER FLOODING ON CHENANGO RIVER AT SHERBURNE. FORECASTED FLOODING ON CHENANGO RIVER AT NORWICH AND GREENE AND THE SUSQUEHANNA RIVER AT CONKLIN, VESTAL, WAVERLY/SAYRE. FLASH FLOOD WATCH CONTINUES AND WAS EXTENDED TO 8 PM. MORE SLOW MOVING THUNDERSTORMS COMING INTO THE CWA. AFTER FLOODING LAST NIGHT IT WILL NOT TAKE MUCH MORE RAIN TO FLOOD. BASIN AVERAGES UNDER AN INCH BUT LOCALIZED AMOUNTS OF OVER AN INCH POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR PAZ038>040- 043-044-047-048-072. NY...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ009- 015>018-022>025-036-037-044>046-055>057-062. && $$ SYNOPSIS...RRM NEAR TERM...MSE/RRM SHORT TERM...RRM LONG TERM...TAC AVIATION...TAC HYDROLOGY...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 PM EDT FRI JUN 28 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY NIGHT/... AS OF 245 PM FRIDAY... THROUGH TONIGHT: LITTLE DOUBT THAT MOST IF NOT ALL OF THE AREA WILL SEE SHOWERS/STORMS IN THE NEXT 18 HOURS. ACCORDING TO CURRENT MESOANALYSES WE CONTINUE TO DESTABILIZE WITH MLCAPE ALREADY UP TO 1500-2500 J/KG AND MUCAPE AROUND 3000 J/KG. A BROKEN LINE OF SHOWERS AND STORMS HAS FORMED OVER SOUTH-CENTRAL AND SW VA INTO THE NC MOUNTAINS... AND THIS CONVECTION IS ON TRACK TO DROP ESE THROUGH CENTRAL NC FROM MID AFTERNOON THROUGH THE EVENING. AS EXPECTED... DEEP LAYER SHEAR CONTINUES TO IMPROVE TO 30-35 KTS... SUPPORTIVE OF ORGANIZED CONVECTION... PARTICULARLY AS THIS INCOMING LINE FEEDS ON A HIGHLY MOIST AND BUOYANT BOUNDARY LAYER WITH TEMPS NEAR 90 (THANKS TO PLENTY OF HEATING THUS FAR) AND DEW POINTS IN THE LOW-MID 70S. EXPECT CONVECTION TO BECOME MORE NUMEROUS AND STRENGTHEN AS IT TAPS INTO THIS JUICIER AIR ALONG AND EAST OF THE HIGHWAY 1 CORRIDOR. RECENT HRRR RUNS DEPICTED THIS SCENARIO FAIRLY WELL... BRINGING SCATTERED STORMS INTO THE TRIAD TOWARD 19-20Z WHICH THEN CONGEAL INTO AN ORGANIZED BAND OF STORM CLUSTERS HEADING EASTWARD THROUGH 04Z. STILL APPEARS THAT SEVERE WIND GUSTS WILL BE THE BIGGEST SEVERE THREAT LATE TODAY INTO TONIGHT GIVEN THAT WE HAVE SOME DRIER AIR NOT FAR OFF THE SURFACE AND DECENT D-CAPE AT OR OVER 800 J/KG. THE -10C TO -30C CAPE IS NOT ESPECIALLY LARGE BUT HAS RISEN A BIT IN RECENT HOURS TO NEAR 500 J/KG EAST OF THE HIGHER TERRAIN... THUS LARGE HAIL REMAINS POSSIBLE BUT IS A SECONDARY THREAT. WILL CONTINUE TO TREND POPS DOWN AND OUT GRADUALLY WEST TO EAST AFTER MIDNIGHT WITH LOSS OF HEATING. FOG/STRATUS HAS BEEN TOUGH TO FORECAST THE LAST FEW DAYS BUT WILL LEAN TOWARD PERSISTENCE... WITH BETTER COVERAGE EAST OF HIGHWAY 1 WITHIN A VERY LIGHT SW FLOW. FOR SATURDAY/SATURDAY NIGHT: CONTINUED WARM... DAMP... AND HUMID. WE`LL REMAIN BENEATH CLIMATOLOGICALLY FAST CYCLONIC MID LEVEL FLOW HEADING INTO THE WEEKEND. MODELS SHOW THE SURFACE TROUGH SHIFTING TO THE COASTAL PLAIN SATURDAY MORNING WITH MARKEDLY LOWER SURFACE THETA-E VALUES PUSHING INTO THE WRN FORECAST AREA. EXPECT TO SEE SOME LINGERING PATCHY SHOWERS ALONG WITH AREAS OF STRATUS OVER THE COASTAL PLAIN SATURDAY MORNING... BUT WEAK TO ABSENT DYNAMIC FORCING FOR ASCENT AND TYPICALLY LOWER INSTABILITY AND LINGERING CINH THAT TIME OF DAY WILL LIMIT COVERAGE/STRENGTH OF ANY CONVECTION DURING THE MORNING... AND THE WRN PIEDMONT SHOULD REMAIN DRY THROUGH MIDDAY. WITH THE INJECTION OF ENERGY DOWN ITS WEST SIDE... THE MID LEVEL TROUGH IS EXPECTED TO DIG STRONGLY DOWN LAKE MICHIGAN INTO IN AND THE WRN OH VALLEY THROUGH SATURDAY NIGHT... CAUSING A BACKING OF MID LEVEL WINDS OVER NC TO A MORE SOUTHERLY DIRECTION AND A GRADUAL STRENGTHENING AND BUILDING OF THE ATLANTIC ANTICYCLONE WESTWARD TOWARD COASTAL NC. THIS WILL EFFECTIVELY LEAD TO DISSIPATION OF THE ERN NC SURFACE TROUGH WHILE THE MORE SUBSTANTIAL FRONTAL ZONE STRENGTHENS TO OUR WEST AND HIGH PW VALUES REBOUND BACK WESTWARD THROUGH CENTRAL NC WITH AN ATTENDING RESURGENCE OF HIGHER 850 MB THETA-E. THE NAM/GFS HANDLE THEIR PRECIP FIELDS DIFFERENTLY WITH THE NAM HOLDING WIDESPREAD CONVECTION TO OUR EAST AND WEST UNTIL VERY LATE SATURDAY NIGHT... WHILE THE GFS DEVELOPS CONVECTION WITH HEATING SATURDAY AFTERNOON ESPECIALLY ALONG THE HIGHWAY 1 CORRIDOR... WHICH THEN PERSISTS THROUGH THE NIGHT AS THE 2+ INCH PRECIP WATER VALUES SPREAD FROM THE COAST WESTWARD THROUGH ALL OF CENTRAL NC. THE GFS`S PATTERN LOOKS TO BE A MORE REASONABLE SCENARIO... WITH MORE SCATTERED DISCRETE CELLS IN THE FAR WRN PIEDMONT (WHERE SURFACE DEW POINTS AND HENCE INSTABILITY WILL LIKELY BE A BIT LOWER) TRENDING TO NUMEROUS CLUSTERS OF MULTICELLS ROUGHLY EAST OF A LINE FROM ROXBORO TO SILER CITY TO WADESBORO (ATTENDING THE GREATER INSTABILITY AND PW). THE BACKED STEERING FLOW AND EXPECTED ORIENTATION OF CONVECTIVE BANDS WILL BRING ABOUT A CONCERN FOR TRAINING ECHOES AND LOCALIZED URBAN AND STREET FLOODING AND SWOLLEN CREEKS STARTING SATURDAY... ESPECIALLY CONSIDERING THE IMPROVING UPPER DIVERGENCE OVER CENTRAL/ERN NC IN THE RIGHT ENTRANCE REGION OF THE SOUTHERLY JET TO OUR NNW. AFTER MUCH COORDINATION AND DISCUSSION... WILL NOT GO WITH A FLASH FLOOD WATCH AS YET... AS WIDESPREAD HEAVY RAIN HAS YET TO MATERIALIZE IN THE ERN PIEDMONT/SANDHILLS/COASTAL PLAIN WHERE THE MORE SANDY SOIL AND FLATTER TERRAIN RESULTS IN SLOWER RUNOFF... BUT URBAN AREAS WILL REMAIN VULNERABLE TO SOME FLOODING. WE WILL CONTINUE TO RE-EVALUATE AND CONSIDER THIS RISK AS WE HEAD THROUGH THE WEEKEND. WILL HAVE A GOOD CHANCE OF SHOWERS/STORMS WEST SATURDAY AFTERNOON/NIGHT WITH LIKELY POPS ALONG/EAST OF THE AFOREMENTIONED LINE COVERING THE CENTRAL/ERN CWA. DEEP LAYER SHEAR IS NOT TREMENDOUS BUT DOES IMPROVE FURTHER TO 25-35 KTS... ALTHOUGH MODEL MLCAPE VALUES ONLY PEAK AT 800-1500 J/KG SATURDAY AFTERNOON ALONG/EAST OF HIGHWAY 1... SUGGESTING PERHAPS A MORE MOIST-ADIABATIC PROFILE THAN WE`VE SEEN LATELY. POTENTIALLY WEAKER UPDRAFTS ESPECIALLY ALOFT COULD LOWER THE RISK OF SEVERE STORMS... BUT AGAIN THE DEEP WARM LAYER (LCL TO FREEZING DEPTH NEAR 4 KM) AND PW NEAR 2 INCHES (WHICH IS NEARLY 2 STANDARD DEVIATIONS ABOVE NORMAL) SUPPORT A HEAVY RAIN THREAT WITH WARM RAIN PROCESSES DOMINATING. HIGHS 87-91. LOWS 68-72. -GIH && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 245 PM FRIDAY... THE WELL-ADVERTISED DEVELOPING TROUGH ALOFT WILL HAVE BECOME STRONGLY AMPLIFIED AND ESTABLISHED OVER THE TN VALLEY THIS PERIOD...BETWEEN A PAIR OF ANOMALOUSLY STRONG RIDGES OVER WESTERN N. AMERICA AND THE WESTERN N. ATLANTIC. WHILE LOW LEVEL CONVERGENCE IN ASSOCIATION WITH A LEE TROUGH/WEAK FRONT WILL HAVE DIMINISHED FROM PREVIOUS DAYS...THE PATTERN OF PERTURBED SW TO SSW DEEP LAYER FLOW WILL DRIVE NUMEROUS TO WIDESPREAD SHOWERS/STORMS...AMIDST A DEEP MOIST AXIS CHARACTERIZED BY PRECIPITABLE WATER VALUES AROUND TWO INCHES...SUNDAY AND LIKELY THROUGHOUT SUNDAY NIGHT. DEEP LAYER SHEAR ON THE ORDER OF 25-30 KTS...TO PERHAPS 35 KTS OVER THE NW PIEDMONT...WILL SUPPORT PRIMARILY MULTI-CELL BANDS CAPABLE OF PRODUCING WET MICROBURSTS...AND TO A GREATER EXTENT LOCALIZED FLOODING OWING THE ANOMALOUSLY HIGH PW/S. HIGHS GENERALLY IN THE MID 80S...AND LOWER 70S FOR LOWS. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 255 PM FRIDAY... CONTINUED...IF NOT INCREASINGLY...WET. THE LARGE SCALE RIDGE/TROUGH/RIDGE CONFIGURATION ACROSS NOAM WILL GRADUALLY RETROGRESS...WITH THE TROUGH DRIFTING WESTWARD INTO THE MS VALLEY...THROUGH MID-LATE WEEK. THE PRESENCE AND PERSISTENCE OF THE TROUGH WILL KEEP MUCH OF THE EASTERN US...INCLUDING CENTRAL NC...IN A PATTERN OF PERTURBED AND DEEPLY MOIST SW TO SSW FLOW ALOFT - FAVORABLE FOR ABOVE AVERAGE PRECIPITATION CHANCES...PARTICULARLY THROUGH WEDNESDAY. THE PROLONGED STORMY PERIOD WILL FAVOR AN INCREASING RISK OF FLOODING WITH EACH DAY THAT PASSES...WITH OTHERWISE AN OCCASIONAL PRECIPITATION-LOADED WET MICROBURST FROM LOOSELY ORGANIZED MULTI-CELL STORM MODES DRIVEN BY GENERALLY 20-25 KTS OF MID LEVEL FLOW. ASIDE FROM THE 00Z/28TH ECMWF...THE CONSENSUS OF MEDIUM RANGE GUIDANCE...INCLUDING THE 00Z ECMWF ENSEMBLE MEAN...INDICATES THE PATTERN RETROGRESSION WILL ALLOW THE WESTERN ATLANTIC SUB-TROPICAL RIDGING TO EXPAND WESTWARD SUFFICIENTLY TO LESSEN PRECIPITATION CHANCES/COVERAGE - FROM NUMEROUS/WIDESPREAD TO SCATTERED - OVER EASTERN NC...INCLUDING THE RAH COASTAL PLAIN...BY MID TO LATE WEEK. HIGHS MOSTLY IN THE MIDDLE 80S...WITH LOWS 70 TO 75. && .AVIATION /18Z THURSDAY THROUGH WEDNESDAY/... AS OF 135 PM FRIDAY... THIS MORNING`S IFR STRATUS AFFECTING RDU/RWI/FAY HAS SHIFTED EASTWARD AND MIXED OUT... AND VFR CONDITIONS WILL DOMINATE THIS AFTERNOON. BUT WE REMAIN IN A WARM... HUMID... AND UNSETTLED PATTERN OVER CENTRAL NC... WITH A HIGH PROBABILITY OF STORMS PARTICULARLY AT RDU/RWI/FAY MID-LATE AFTERNOON THROUGH TONIGHT. LOCAL TORRENTIAL DOWNPOURS WITH BRIEF IFR/LIFR CONDITIONS ARE POSSIBLE WITH THESE SHOWERS AND STORMS... ALONG WITH THE POTENTIAL FOR SURFACE WIND GUSTS OVER 40 MPH. SCATTERED STORMS ARE EXPECTED NEAR INT/GSO AFTER 19Z... SPREADING EASTWARD TOWARD RDU/RWI/FAY AFTER 21Z AND BECOMING NUMEROUS. STORM CHANCES WILL PERSIST IN LATE EVENING AT RDU/RWI/FAY... TAPERING TO LIGHTER AND MORE PATCHY SHOWERS LATE TONIGHT. BASED ON THE PERSISTENCE OF THIS PATTERN... AREAS OF IFR/LIFR STRATUS ARE POSSIBLE AFTER 07Z TONIGHT AT RDU/RWI/FAY... BUT ONCE AGAIN THE MODELS ARE PRESENTING CONFLICTING GUIDANCE REGARDING THIS THREAT... SO CONFIDENCE IN OCCURRENCE OF A PREDOMINANT IFR/LIFR CIG IS LOW. ANY SUCH STRATUS WOULD LIFT BY 14Z SATURDAY MORNING... AND VFR CONDITIONS WOULD THEN HOLD THROUGH 18Z. LOOKING BEYOND 18Z SATURDAY... SHOWERS/STORMS AND ATTENDANT MVFR OR IFR CONDITIONS ARE EXPECTED TO BECOME MORE NUMEROUS SATURDAY AFTERNOON INTO THE NIGHT... SO EXPECT INCREASINGLY POTENTIAL FOR ADVERSE AVIATION CONDITIONS... ESPECIALLY AT RDU/RWI/FAY. WITH MINIMAL CHANGE IN THE OVERALL PATTERN OVER THE CONUS... THE RISK FOR DAILY NUMEROUS SUB-VFR SHOWERS AND STORMS (PRIMARILY FROM MID AFTERNOON THROUGH MIDNIGHT) AND SHALLOW EARLY-MORNING IFR STRATUS IS EXPECTED TO PERSIST INTO THE MIDDLE OF NEXT WEEK. -GIH && .EQUIPMENT... KRAX WSR-88D IS BACK IN OPERATIONAL SERVICE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...MWS LONG TERM...MWS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 PM EDT FRI JUN 28 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY NIGHT/... AS OF 245 PM FRIDAY... THROUGH TONIGHT: LITTLE DOUBT THAT MOST IF NOT ALL OF THE AREA WILL SEE SHOWERS/STORMS IN THE NEXT 18 HOURS. ACCORDING TO CURRENT MESOANALYSES WE CONTINUE TO DESTABILIZE WITH MLCAPE ALREADY UP TO 1500-2500 J/KG AND MUCAPE AROUND 3000 J/KG. A BROKEN LINE OF SHOWERS AND STORMS HAS FORMED OVER SOUTH-CENTRAL AND SW VA INTO THE NC MOUNTAINS... AND THIS CONVECTION IS ON TRACK TO DROP ESE THROUGH CENTRAL NC FROM MID AFTERNOON THROUGH THE EVENING. AS EXPECTED... DEEP LAYER SHEAR CONTINUES TO IMPROVE TO 30-35 KTS... SUPPORTIVE OF ORGANIZED CONVECTION... PARTICULARLY AS THIS INCOMING LINE FEEDS ON A HIGHLY MOIST AND BUOYANT BOUNDARY LAYER WITH TEMPS NEAR 90 (THANKS TO PLENTY OF HEATING THUS FAR) AND DEW POINTS IN THE LOW-MID 70S. EXPECT CONVECTION TO BECOME MORE NUMEROUS AND STRENGTHEN AS IT TAPS INTO THIS JUICIER AIR ALONG AND EAST OF THE HIGHWAY 1 CORRIDOR. RECENT HRRR RUNS DEPICTED THIS SCENARIO FAIRLY WELL... BRINGING SCATTERED STORMS INTO THE TRIAD TOWARD 19-20Z WHICH THEN CONGEAL INTO AN ORGANIZED BAND OF STORM CLUSTERS HEADING EASTWARD THROUGH 04Z. STILL APPEARS THAT SEVERE WIND GUSTS WILL BE THE BIGGEST SEVERE THREAT LATE TODAY INTO TONIGHT GIVEN THAT WE HAVE SOME DRIER AIR NOT FAR OFF THE SURFACE AND DECENT D-CAPE AT OR OVER 800 J/KG. THE -10C TO -30C CAPE IS NOT ESPECIALLY LARGE BUT HAS RISEN A BIT IN RECENT HOURS TO NEAR 500 J/KG EAST OF THE HIGHER TERRAIN... THUS LARGE HAIL REMAINS POSSIBLE BUT IS A SECONDARY THREAT. WILL CONTINUE TO TREND POPS DOWN AND OUT GRADUALLY WEST TO EAST AFTER MIDNIGHT WITH LOSS OF HEATING. FOG/STRATUS HAS BEEN TOUGH TO FORECAST THE LAST FEW DAYS BUT WILL LEAN TOWARD PERSISTENCE... WITH BETTER COVERAGE EAST OF HIGHWAY 1 WITHIN A VERY LIGHT SW FLOW. FOR SATURDAY/SATURDAY NIGHT: CONTINUED WARM... DAMP... AND HUMID. WE`LL REMAIN BENEATH CLIMATOLOGICALLY FAST CYCLONIC MID LEVEL FLOW HEADING INTO THE WEEKEND. MODELS SHOW THE SURFACE TROUGH SHIFTING TO THE COASTAL PLAIN SATURDAY MORNING WITH MARKEDLY LOWER SURFACE THETA-E VALUES PUSHING INTO THE WRN FORECAST AREA. EXPECT TO SEE SOME LINGERING PATCHY SHOWERS ALONG WITH AREAS OF STRATUS OVER THE COASTAL PLAIN SATURDAY MORNING... BUT WEAK TO ABSENT DYNAMIC FORCING FOR ASCENT AND TYPICALLY LOWER INSTABILITY AND LINGERING CINH THAT TIME OF DAY WILL LIMIT COVERAGE/STRENGTH OF ANY CONVECTION DURING THE MORNING... AND THE WRN PIEDMONT SHOULD REMAIN DRY THROUGH MIDDAY. WITH THE INJECTION OF ENERGY DOWN ITS WEST SIDE... THE MID LEVEL TROUGH IS EXPECTED TO DIG STRONGLY DOWN LAKE MICHIGAN INTO IN AND THE WRN OH VALLEY THROUGH SATURDAY NIGHT... CAUSING A BACKING OF MID LEVEL WINDS OVER NC TO A MORE SOUTHERLY DIRECTION AND A GRADUAL STRENGTHENING AND BUILDING OF THE ATLANTIC ANTICYCLONE WESTWARD TOWARD COASTAL NC. THIS WILL EFFECTIVELY LEAD TO DISSIPATION OF THE ERN NC SURFACE TROUGH WHILE THE MORE SUBSTANTIAL FRONTAL ZONE STRENGTHENS TO OUR WEST AND HIGH PW VALUES REBOUND BACK WESTWARD THROUGH CENTRAL NC WITH AN ATTENDING RESURGENCE OF HIGHER 850 MB THETA-E. THE NAM/GFS HANDLE THEIR PRECIP FIELDS DIFFERENTLY WITH THE NAM HOLDING WIDESPREAD CONVECTION TO OUR EAST AND WEST UNTIL VERY LATE SATURDAY NIGHT... WHILE THE GFS DEVELOPS CONVECTION WITH HEATING SATURDAY AFTERNOON ESPECIALLY ALONG THE HIGHWAY 1 CORRIDOR... WHICH THEN PERSISTS THROUGH THE NIGHT AS THE 2+ INCH PRECIP WATER VALUES SPREAD FROM THE COAST WESTWARD THROUGH ALL OF CENTRAL NC. THE GFS`S PATTERN LOOKS TO BE A MORE REASONABLE SCENARIO... WITH MORE SCATTERED DISCRETE CELLS IN THE FAR WRN PIEDMONT (WHERE SURFACE DEW POINTS AND HENCE INSTABILITY WILL LIKELY BE A BIT LOWER) TRENDING TO NUMEROUS CLUSTERS OF MULTICELLS ROUGHLY EAST OF A LINE FROM ROXBORO TO SILER CITY TO WADESBORO (ATTENDING THE GREATER INSTABILITY AND PW). THE BACKED STEERING FLOW AND EXPECTED ORIENTATION OF CONVECTIVE BANDS WILL BRING ABOUT A CONCERN FOR TRAINING ECHOES AND LOCALIZED URBAN AND STREET FLOODING AND SWOLLEN CREEKS STARTING SATURDAY... ESPECIALLY CONSIDERING THE IMPROVING UPPER DIVERGENCE OVER CENTRAL/ERN NC IN THE RIGHT ENTRANCE REGION OF THE SOUTHERLY JET TO OUR NNW. AFTER MUCH COORDINATION AND DISCUSSION... WILL NOT GO WITH A FLASH FLOOD WATCH AS YET... AS WIDESPREAD HEAVY RAIN HAS YET TO MATERIALIZE IN THE ERN PIEDMONT/SANDHILLS/COASTAL PLAIN WHERE THE MORE SANDY SOIL AND FLATTER TERRAIN RESULTS IN SLOWER RUNOFF... BUT URBAN AREAS WILL REMAIN VULNERABLE TO SOME FLOODING. WE WILL CONTINUE TO RE-EVALUATE AND CONSIDER THIS RISK AS WE HEAD THROUGH THE WEEKEND. WILL HAVE A GOOD CHANCE OF SHOWERS/STORMS WEST SATURDAY AFTERNOON/NIGHT WITH LIKELY POPS ALONG/EAST OF THE AFOREMENTIONED LINE COVERING THE CENTRAL/ERN CWA. DEEP LAYER SHEAR IS NOT TREMENDOUS BUT DOES IMPROVE FURTHER TO 25-35 KTS... ALTHOUGH MODEL MLCAPE VALUES ONLY PEAK AT 800-1500 J/KG SATURDAY AFTERNOON ALONG/EAST OF HIGHWAY 1... SUGGESTING PERHAPS A MORE MOIST-ADIABATIC PROFILE THAN WE`VE SEEN LATELY. POTENTIALLY WEAKER UPDRAFTS ESPECIALLY ALOFT COULD LOWER THE RISK OF SEVERE STORMS... BUT AGAIN THE DEEP WARM LAYER (LCL TO FREEZING DEPTH NEAR 4 KM) AND PW NEAR 2 INCHES (WHICH IS NEARLY 2 STANDARD DEVIATIONS ABOVE NORMAL) SUPPORT A HEAVY RAIN THREAT WITH WARM RAIN PROCESSES DOMINATING. HIGHS 87-91. LOWS 68-72. -GIH && .SHORT TERM / /... AS OF 300 AM FRIDAY... TO BE UPDATED. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 300 AM FRIDAY... AN UNUSUALLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST THROUGH MUCH OF THE PERIOD AS RIDGES DOMINATE WEST OF THE ROCKIES (EXTENDING UP INTO CANADA) AND ACROSS THE WESTERN ATLANTIC...WITH A DEEP TROUGH SANDWICHED IN THE MIDDLE. THIS TROUGH WILL GRADUALLY RETROGRADE THROUGH THE PERIOD...NEVERTHELESS LEAVING CENTRAL NC WITHIN A PERSISTENT DEEP SOUTHWESTERLY FLOW. AS A RESULT...NUMEROUS DISTURBANCES ALOFT WILL MOVE ACROSS THE AREA AND WITH MOISTURE REMAINING HIGH (BETWEEN 1.75-2 INCHES)...UNSETTLED WEATHER WILL CONTINUE THROUGH THE ENTIRE LONG TERM PERIOD (IF NOT LONGER)...WITH ABOVE NORMAL CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY (MOSTLY DIURNALLY DRIVEN). AS THE UPPER LEVEL TROUGH RETROGRADES...THE RIDGE OVER THE WESTERN ATLANTIC WILL PUSH WESTWARD...THEREFORE EVENTUALLY EXERTING SOME MORE INFLUENCE OVER THE REGION BY THE MIDDLE/LATTER PORTION OF THE WEEK. THIS IS WHEN WE MAY START SEEING A DECREASE IN PRECIP COVERAGE... ESPECIALLY OVER EASTERN NC. OTHERWISE...WITH THE INCREASED FLOW ALOFT...DECENT DEEP LAYER SHEAR WILL PERSIST OVER THE AREA AND THEREFORE WE SHOULD SEE MORE IN THE WAY OF ORGANIZED CONVECTION. THIS MAY RESULT IN SOME STRONG TO SEVERE STORMS. ANOTHER SIGNIFICANT WEATHER THREAT WILL BE THE INCREASING FLOODING RISK AS THE AREA REMAINS IN THIS EXTENDED WET PATTERN. DAYTIME HIGHS WILL GENERALLY BE BELOW NORMAL THROUGH THE PERIOD...WITH MOSTLY MID 80S EXPECTED. OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S. && .AVIATION /18Z THURSDAY THROUGH WEDNESDAY/... AS OF 135 PM FRIDAY... THIS MORNING`S IFR STRATUS AFFECTING RDU/RWI/FAY HAS SHIFTED EASTWARD AND MIXED OUT... AND VFR CONDITIONS WILL DOMINATE THIS AFTERNOON. BUT WE REMAIN IN A WARM... HUMID... AND UNSETTLED PATTERN OVER CENTRAL NC... WITH A HIGH PROBABILITY OF STORMS PARTICULARLY AT RDU/RWI/FAY MID-LATE AFTERNOON THROUGH TONIGHT. LOCAL TORRENTIAL DOWNPOURS WITH BRIEF IFR/LIFR CONDITIONS ARE POSSIBLE WITH THESE SHOWERS AND STORMS... ALONG WITH THE POTENTIAL FOR SURFACE WIND GUSTS OVER 40 MPH. SCATTERED STORMS ARE EXPECTED NEAR INT/GSO AFTER 19Z... SPREADING EASTWARD TOWARD RDU/RWI/FAY AFTER 21Z AND BECOMING NUMEROUS. STORM CHANCES WILL PERSIST IN LATE EVENING AT RDU/RWI/FAY... TAPERING TO LIGHTER AND MORE PATCHY SHOWERS LATE TONIGHT. BASED ON THE PERSISTENCE OF THIS PATTERN... AREAS OF IFR/LIFR STRATUS ARE POSSIBLE AFTER 07Z TONIGHT AT RDU/RWI/FAY... BUT ONCE AGAIN THE MODELS ARE PRESENTING CONFLICTING GUIDANCE REGARDING THIS THREAT... SO CONFIDENCE IN OCCURRENCE OF A PREDOMINANT IFR/LIFR CIG IS LOW. ANY SUCH STRATUS WOULD LIFT BY 14Z SATURDAY MORNING... AND VFR CONDITIONS WOULD THEN HOLD THROUGH 18Z. LOOKING BEYOND 18Z SATURDAY... SHOWERS/STORMS AND ATTENDANT MVFR OR IFR CONDITIONS ARE EXPECTED TO BECOME MORE NUMEROUS SATURDAY AFTERNOON INTO THE NIGHT... SO EXPECT INCREASINGLY POTENTIAL FOR ADVERSE AVIATION CONDITIONS... ESPECIALLY AT RDU/RWI/FAY. WITH MINIMAL CHANGE IN THE OVERALL PATTERN OVER THE CONUS... THE RISK FOR DAILY NUMEROUS SUB-VFR SHOWERS AND STORMS (PRIMARILY FROM MID AFTERNOON THROUGH MIDNIGHT) AND SHALLOW EARLY-MORNING IFR STRATUS IS EXPECTED TO PERSIST INTO THE MIDDLE OF NEXT WEEK. -GIH && .EQUIPMENT... KRAX WSR-88D WILL REMAIN DOWN OR IN DEGRADED MODE THROUGH MID AFTERNOON TODAY. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS ARE MAKING THESE REPAIRS AS QUICKLY AS POSSIBLE... AND IS WORKING HARD TO RETURN THE RADAR TO NORMAL SERVICE THIS AFTERNOON. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...CBL LONG TERM...KRR AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
135 PM EDT FRI JUN 28 2013 .SYNOPSIS... A WARM AND HUMID AIR MASS COMBINED WITH A PERSISTENT TROUGH OF LOW PRESSURE OVER THE REGION WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1040 AM FRIDAY... LITTLE DOUBT THAT MOST OF THE AREA WILL SEE SHOWERS/STORMS SOMETIME IN THE NEXT 18 HOURS... ALTHOUGH IT LOOKS LIKE WE MAY SEE A SLIGHT DELAY IN THE MORE ORGANIZED CONVECTION UNTIL LATER IN THE DAY. ACCORDING TO CURRENT MESOANALYSES WE ARE SLOWLY DESTABILIZING BUT WITH A LOT OF REMAINING CINH. LATEST SATELLITE IMAGERY SHOWS THAT MUCH OF THE MORNING STRATUS IN THE COASTAL PLAIN IS SLOWLY MOVING OUT TO THE EAST... WHILE THE WRN SECTIONS ARE SEEING HIGH THIN CLOUDS ASSOCIATED WITH THE NOW-DYING MCS DIVING FROM MEMPHIS INTO MS/AL. OVERNIGHT RUNS OF THE RAP MODEL HAVE HAD A DIFFICULT TIME WITH THE MCV TO OUR WEST... TRACKING IT EASTWARD THROUGH THE CAROLINAS WHEN TRAJECTORIES AND OBSERVATIONS SUGGEST THAT IT WILL TAKE A MORE SRN ROUTE THROUGH AL AND PERHAPS GA. WITH THIS FEATURE LIKELY SLIDING TO OUR SOUTH... WHILE ANOTHER AREA OF ENHANCED MID/HIGH-LEVEL FORCING FOR ASCENT TRACKS UP THROUGH PA... NC COULD BE LEFT BENEATH A RELATIVE MINIMUM IN TERMS OF LARGE SCALE DYNAMIC FORCING. THAT SAID... DEEP LAYER SHEAR IS EXPECTED TO STEADILY INCREASE THROUGH THE DAY -- ESPECIALLY INTO THE EVENING -- AND WITH THE DEARTH OF MORNING CLOUD COVER LEADING TO GOOD HEATING (TEMPS ARE RUNNING A FEW DEGREES COOLER THAN YESTERDAY IN THE SOUTHEAST BUT 1-7 DEGREES WARMER THAN THIS TIME THURSDAY OVER THE REST OF CENTRAL NC) AND MODELS PROJECTING 1500-2500 J/KG OF MLCAPE OVER ALL BUT THE NW CWA BY MID AFTERNOON... SEE NO REASON TO THINK THAT WE WON`T SEE INCREASING STORMS (IN NUMBER AND INTENSITY) HEADING THROUGH THE MID-LATE AFTERNOON AND THROUGH THE EVENING. THE LATEST HRRR RUN DEPICTS THIS SCENARIO QUITE WELL... BRINGING SCATTERED STORMS INTO THE TRIAD TOWARD 19-20Z THEN CONGEALING INTO AN ORGANIZED BAND OF STORM CLUSTERS HEADING EASTWARD THROUGH 04Z. STILL APPEARS THAT SEVERE WIND GUSTS WILL BE THE BIGGEST THREAT LATE TODAY INTO TONIGHT GIVEN THAT WE HAVE SOME DRY AIR NOT FAR OFF THE SURFACE. THE -10C TO -30C CAPE IS QUITE LOW THIS MORNING AND DON`T EXPECT THAT TO CHANGE MUCH WITH ONLY MINIMAL COOLING ALOFT AND NO APPARENT OPPORTUNITY FOR GOOD MOISTURE FLUX IN THIS MIXED PHASE REGION... THUS THE RISK OF LARGE HAIL SHOULD BE SECONDARY. IT IS INTERESTING HOW VERY DRY THE 12Z GSO SOUNDING WAS... WITH A PW OF 1.02 INCHES... MUCH LOWER THAN IN PAST DAYS AND A BIT OF AN OUTLIER COMPARED TO SURROUNDING UPPER AIR PLOTS. IT ALSO DEPARTS QUITE A BIT FROM THE PW NOTED ON TPW BLENDED IMAGERY (AROUND 1.4 INCHES IN THE TRIAD). MODELS DO SHOW A REMOISTENING OF THE COLUMN HERE THIS AFTERNOON... TOUGH TO BELIEVE CONSIDERING THE OBSERVED UPPER-AIR DATA UPSTREAM THIS MORNING AND THE LOW DEW POINTS IN THE TRIAD. WILL LEAVE IN GOOD CHANCE POPS HERE FOR NOW GIVEN THE IMPROVING BULK SHEAR THROUGH THE DAY... ALTHOUGH WE SHOULD SEE A RELATIVE MINIMUM IN COVERAGE IN THE TRIAD. LITTLE CHANGE IN HIGHS WITH TEMP TRENDS SUPPORTING READINGS OF 89-94. WILL CONTINUE TO TREND POPS DOWN AND OUT WEST TO EAST ESPECIALLY AFTER MIDNIGHT WITH LOSS OF HEATING. FOG/STRATUS HAS BEEN TOUGH TO FORECAST THE LAST FEW DAYS BUT WILL LEAN TOWARD PERSISTENCE... WITH BETTER COVERAGE EAST OF HIGHWAY 1 WITHIN A VERY LIGHT SW FLOW. -GIH && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM FRIDAY... AS THE UPPER TROUGH CONTINUES TO DEEPEN...MID TO UPPER LEVEL FLOW WILL BECOME SWLY AND WE WILL HAVE TO BE CONCERN WITH SHORTWAVE IMPULSES FROM THE SW AS OPPOSE TO THE W-NW FROM RECENT DAYS. ANOTHER IMPORTANT DIFFERENCE TO NOTE IS HOW MODELS ARE HANDLING THE MEANDERING SURFACE TROUGH/FRONT WITH BOTH THE NAM AND GFS ADVECTING CONSIDERABLY LOWER THETA-E AIR INTO THE LOW-LEVELS...WHICH EFFECTIVELY LESSENS CAPE OVER THE WESTERN PIEDMONT. THIS WOULD POTENTIALLY CONFINE THE BEST CONVECTIVE ACTIVITY TO EASTERN NC WITH LOWER PRECIP PROBABILITIES THAN CURRENTLY FORECASTING ACROSS THE WESTERN AND POSSIBLY CENTRAL PIEDMONT. FOR STORMS THAT DO DEVELOP...THE MODEST MID-LEVEL WIND FIELD OF 30 TO 35KTS AND STRONG DESTABILIZATION WITH 2000 TO 2500 J/KG OF MLCAPE WILL ONCE AGAIN SUPPORT THE THREAT FOR DAMAGING WING GUSTS AND HAIL. ADDITIONALLY WITH THE UPPER FLOW NOW PARALLEL TO THE WEAK SURFACE BOUNDARY...EASTERN AREAS WE WILL HAVE TO BE ON THE ALERT FOR FOR TRAINING OF STORMS AND THE INHERENT HEAVY RAIN AND FLOODING THREAT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 300 AM FRIDAY... AN UNUSUALLY AMPLIFIED UPPER LEVEL PATTERN WILL PERSIST THROUGH MUCH OF THE PERIOD AS RIDGES DOMINATE WEST OF THE ROCKIES (EXTENDING UP INTO CANADA) AND ACROSS THE WESTERN ATLANTIC...WITH A DEEP TROUGH SANDWICHED IN THE MIDDLE. THIS TROUGH WILL GRADUALLY RETROGRADE THROUGH THE PERIOD...NEVERTHELESS LEAVING CENTRAL NC WITHIN A PERSISTENT DEEP SOUTHWESTERLY FLOW. AS A RESULT...NUMEROUS DISTURBANCES ALOFT WILL MOVE ACROSS THE AREA AND WITH MOISTURE REMAINING HIGH (BETWEEN 1.75-2 INCHES)...UNSETTLED WEATHER WILL CONTINUE THROUGH THE ENTIRE LONG TERM PERIOD (IF NOT LONGER)...WITH ABOVE NORMAL CHANCES OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED EACH DAY (MOSTLY DIURNALLY DRIVEN). AS THE UPPER LEVEL TROUGH RETROGRADES...THE RIDGE OVER THE WESTERN ATLANTIC WILL PUSH WESTWARD...THEREFORE EVENTUALLY EXERTING SOME MORE INFLUENCE OVER THE REGION BY THE MIDDLE/LATTER PORTION OF THE WEEK. THIS IS WHEN WE MAY START SEEING A DECREASE IN PRECIP COVERAGE... ESPECIALLY OVER EASTERN NC. OTHERWISE...WITH THE INCREASED FLOW ALOFT...DECENT DEEP LAYER SHEAR WILL PERSIST OVER THE AREA AND THEREFORE WE SHOULD SEE MORE IN THE WAY OF ORGANIZED CONVECTION. THIS MAY RESULT IN SOME STRONG TO SEVERE STORMS. ANOTHER SIGNIFICANT WEATHER THREAT WILL BE THE INCREASING FLOODING RISK AS THE AREA REMAINS IN THIS EXTENDED WET PATTERN. DAYTIME HIGHS WILL GENERALLY BE BELOW NORMAL THROUGH THE PERIOD...WITH MOSTLY MID 80S EXPECTED. OVERNIGHT LOWS WILL MOSTLY BE IN THE LOWER 70S. && .AVIATION /18Z THURSDAY THROUGH WEDNESDAY/... AS OF 135 PM FRIDAY... THIS MORNING`S IFR STRATUS AFFECTING RDU/RWI/FAY HAS SHIFTED EASTWARD AND MIXED OUT... AND VFR CONDITIONS WILL DOMINATE THIS AFTERNOON. BUT WE REMAIN IN A WARM... HUMID... AND UNSETTLED PATTERN OVER CENTRAL NC... WITH A HIGH PROBABILITY OF STORMS PARTICULARLY AT RDU/RWI/FAY MID-LATE AFTERNOON THROUGH TONIGHT. LOCAL TORRENTIAL DOWNPOURS WITH BRIEF IFR/LIFR CONDITIONS ARE POSSIBLE WITH THESE SHOWERS AND STORMS... ALONG WITH THE POTENTIAL FOR SURFACE WIND GUSTS OVER 40 MPH. SCATTERED STORMS ARE EXPECTED NEAR INT/GSO AFTER 19Z... SPREADING EASTWARD TOWARD RDU/RWI/FAY AFTER 21Z AND BECOMING NUMEROUS. STORM CHANCES WILL PERSIST IN LATE EVENING AT RDU/RWI/FAY... TAPERING TO LIGHTER AND MORE PATCHY SHOWERS LATE TONIGHT. BASED ON THE PERSISTENCE OF THIS PATTERN... AREAS OF IFR/LIFR STRATUS ARE POSSIBLE AFTER 07Z TONIGHT AT RDU/RWI/FAY... BUT ONCE AGAIN THE MODELS ARE PRESENTING CONFLICTING GUIDANCE REGARDING THIS THREAT... SO CONFIDENCE IN OCCURRENCE OF A PREDOMINANT IFR/LIFR CIG IS LOW. ANY SUCH STRATUS WOULD LIFT BY 14Z SATURDAY MORNING... AND VFR CONDITIONS WOULD THEN HOLD THROUGH 18Z. LOOKING BEYOND 18Z SATURDAY... SHOWERS/STORMS AND ATTENDANT MVFR OR IFR CONDITIONS ARE EXPECTED TO BECOME MORE NUMEROUS SATURDAY AFTERNOON INTO THE NIGHT... SO EXPECT INCREASINGLY POTENTIAL FOR ADVERSE AVIATION CONDITIONS... ESPECIALLY AT RDU/RWI/FAY. WITH MINIMAL CHANGE IN THE OVERALL PATTERN OVER THE CONUS... THE RISK FOR DAILY NUMEROUS SUB-VFR SHOWERS AND STORMS (PRIMARILY FROM MID AFTERNOON THROUGH MIDNIGHT) AND SHALLOW EARLY-MORNING IFR STRATUS IS EXPECTED TO PERSIST INTO THE MIDDLE OF NEXT WEEK. -GIH && .EQUIPMENT... KRAX WSR-88D WILL REMAIN DOWN OR IN DEGRADED MODE THROUGH MID AFTERNOON TODAY. KRAX HAS BEEN IN A SEVERELY DEGRADED MODE FOR SEVERAL DAYS... AND THE NEEDED REPAIRS WERE DEEMED TO BE CRITICAL. THE TEAM OF TECHNICIANS ARE MAKING THESE REPAIRS AS QUICKLY AS POSSIBLE... AND IS WORKING HARD TO RETURN THE RADAR TO NORMAL SERVICE THIS AFTERNOON. WE APOLOGIZE FOR THE INCONVENIENCE. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...CBL LONG TERM...KRR AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1244 PM CDT FRI JUN 28 2013 .UPDATE... ISSUED AT 1245 PM CDT FRI JUN 28 2013 NO MAJOR CHANGES PLANNED TO THIS UPDATE. WE WILL ADD AN UPDATED AVIATION AND HYDROLOGY DISCUSSION...OTHERWISE THE CURRENT FORECAST IS IN GOOD SHAPE AND WILL ONLY ADD CURRENT DATA AND TRENDS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 CHALLENGES INCLUDE CLOUD COVER/PRECIPITATION CHANCES TODAY AND THEN TEMPERATURES THROUGH THE PERIOD. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT...BUT WILL LEAN ON LATEST RAP GUIDANCE FOR NEAR TERM FORECAST. FOR TODAY...STRATOCUMULUS DECK ACROSS NORTH-CENTRAL MN WILL EXPAND SOUTH AND WEST THROUGH THE DAY GIVEN CONVECTIVE TEMPERATURES IN THE UPPER 60S TO MID 70S. WITH A 100 KT 300 HPA JET STREAK MOVING THROUGH NORTHWEST FLOW ALOFT AND 500 TO 1000 J/KG OF MLCAPE... SOME OF THESE THERMAL CU MAY GIVE WAY TO SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS. REMOVED POPS ALONG AND WEST OF THE VALLEY THIS MORNING WITH A MOSTLY SUNNY START TO THE DAY...BUT WILL EXPAND CHANCE POPS SOUTH AND WEST WITH INCREASING CLOUD COVER THIS AFTERNOON. BOUNDARY LAYER IS 3 TO 6 C COLDER THAN YESTERDAY... SO EXPECT DAYTIME HIGHS IN THE 70S. WITH 20 TO 30 KTS AT 850 HPA TO MIX TO THE SURFACE...EXPECT ANOTHER BREEZY AFTERNOON WITH WINDS FROM 15 TO 20 MPH AND OCCASIONAL GUSTS UP TO 30 MPH. THERMAL CU WILL DISSIPATE AFTER SUNSET...BUT EXPECT SOME THICKER CLOUD COVER TO TAKE ITS TIME MOVING OUT OF THE REGION OVERNIGHT. WINDS WILL SUBSIDE WITH SURFACE HIGH PRESSURE BUILDING ACROSS THE REGION. OVERNIGHT LOWS WILL BE IN THE 50S. MOST OF SATURDAY WILL BE DRY...BUT DID KEEP 20 POPS REGION-WIDE THROUGH THE DAY AS OPERATIONAL MODELS PAINT SEEMINGLY RANDOM LIGHT QPF IN ASSOCIATION WITH A WEAK SHORT-WAVE ALOFT. SURFACE TO MID- LEVEL FORCING IS WEAK...SO EXPECT MINIMAL ACCUMULATION WITH ANY SHOWERS THAT DO DEVELOP. ANOTHER COOLER DAY WITH HIGHS AGAIN IN THE 70S. .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 350 AM CDT FRI JUN 28 2013 SURFACE PRESSURE RIDGE WILL SLIDE SLOWLY ACROSS THE NORTHERN PLAINS SUNDAY AND MONDAY RESULTING IN DRY...MOSTLY SUNNY CONDITIONS. WINDS WILL BE LIGHT AND TEMPERATURES WILL BE NEAR SEASONAL NORMALS WITH HIGHS IN THE UPPER 70S TO LOWER 80S. A BLEND OF THE GFS/ECMWF TO BE FOLLOWED EARLY IN THE EXTENDED THEN TRENDING TOWARD THE GFS IN DAYS 5-7. THE UPPER PATTERN AMPLIFIES DURING THE PERIOD WITH RIDGING OVER THE WRN CONUS AND TROF OVER THE ERN THIRD OF THE COUNTRY. THE RIDGING OUT WEST WILL RETROGRADE SOMEWHAT WEST ALLOWING FOR PIECES OF S/WV ENERGY TO SLIDE DOWN THE BACK SIDE OF THE TROF BY TUE/TUE NIGHT. A FRONTAL BOUNDARY ACROSS THE REGION WILL HELP FOCUS PRECIPITATION TUE-THU WITH WED BEING THE MOST OPTIMAL PERIOD FOR SCATTERED SHRA/TSRA. THE BOUNDARY IS EXPECTED TO WEAKEN BY THU. TEMPERATURES WILL BE TEMPERED WITH HIGHS IN THE UPPER 70S TO AROUND 80 THROUGH THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1245 PM CDT FRI JUN 28 2013 CEILINGS HAVE BEEN RISING EAST OF THE VALLEY...AND EXPECT MAINLY VFR SCT/BKN CU THIS AFTERNOON. NORTHWEST WINDS WILL GUST UP TO 25 TO 30 KTS...ESPECIALLY VALLEY WESTWARD...BEFORE DIMINISHING TOWARDS SUNSET. ISO/SCT THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON INTO THE EARLY EVENING. WITH VERY LIMITED COVERAGE...KEPT MOST TERMINALS DRY. DID INCLUDE VICINITY THUNDER FOR A PERIOD LATE THIS AFTERNOON INTO THE EVENING AT KBJI WHERE PRECIP CHANCES APPEAR HIGHEST. WILL HAVE TO MONITOR FOR LOWER CEILINGS LATER TONIGHT INTO THE MORNING...ESPECIALLY TOWARDS KBJI. && .HYDROLOGY... ISSUED AT 1245 PM CDT THU JUN 27 2013 THE RED RIVER AT FARGO IS RIGHT ABOUT CREST CURRENTLY AT OR JUST UNDER THE MAJOR STAGE OF 30 FEET. INCREASES AT LAKE TRAVERSE WILL ACT TO SLOW THE RATE OF FALL AT SOUTHERN VALLEY POINTS. MAINLY MINOR FLOODING WILL CONTINUE ALONG THE SOUTHERN NORTH DAKOTA AND MINNESOTA TRIBUTARIES. FORECAST CRESTS AND RIVER TRACES REMAIN CLOSE TO THE PREVIOUS FORECAST. OTHERWISE...RISES ARE EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS ON CENTRAL AND NORTHERN SECTIONS OF THE RED...WITH A FEW FORECAST POINTS RISING ABOVE MINOR FLOOD STAGE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...DK SHORT TERM...ROGERS LONG TERM...ROGERS/FRAZIER AVIATION...MAKOWSKI HYDROLOGY...WJB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
550 PM EDT FRI JUN 28 2013 .SYNOPSIS... AN UNSEASONABLY INTENSE UPPER TROUGH WILL CARVE OUT OVER THE EASTERN UNITED STATES FROM THE GREAT LAKES TO THE NORTHEASTERN US THROUGH THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL BRING AN EXTENDED PERIOD OF UNSETTLED WEATHER TO THE REGION WHICH COULD LAST INTO THE FIRST DAYS OF JULY. && .NEAR TERM /UNTIL 11 PM THIS EVENING/... DIURNALLY ENHANCED CONVECTION CONTINUES TO FIRE ACROSS MAINLY SOUTHERN PA EARLY THIS EVENING. FFW REMAINS IN AFFECT FOR CLEARFIELD CO...WHERE GROUND REMAINS VERY WET FROM YESTERDAY/S DELUGE AND MODERATE RAIN FALLING AS OF 2130Z. ELSEWHERE...SVR WATCH 386 REMAINS IN EFFECT UNTIL 00Z FOR SOUTHERN PA...WHERE SPC MESOANALYSIS SHOWS CAPES STILL NR 1000 J/KG. EXPECT CONVECTION TO DIMINISH MARKEDLY AFTER SUNSET WITH THREAT OF SVR WX ENDING LAST OVR THE SE COUNTIES BASED ON LATEST RAP OUTPUT. LIGHT WIND...PARTIAL CLEARING AND WET GROUND SHOULD RESULT IN AREAS OF FOG LATER TONIGHT. TEMPS SHOULD BE A BIT COOLER THAN LAST NIGHT...AS SOMEWHAT DRIER AIR WORKS INTO THE REGION. READINGS ARND DAWN SHOULD RANGE FROM THE M50S NW MTNS...TO THE M60S ACROSS THE LOWER SUSQ VALLEY. && .SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/... PRECIP WATER VALUES WILL DIP BY AROUND 0.50 INCH TONIGHT...AND PERIODS OF CLEARING WILL ALLOW TEMPS TO COOL OFF NICELY...ESPECIALLY ACROSS CENTRAL AND NWRN PENN WHERE LOWS EARLY SAT WILL VARY FROM THE MID 50S TO AROUND 60F. LINGERING...SLIGHTLY HIGHER PWATS ACRS THE LOWER SUSQ VALLEY WILL KEEP TEMPS FROM FALLING BELOW THE MID 60S. DAYTIME HIGHS CONTINUE TO TREND DOWNWARD INTO THE WEEKEND WITH HIGH TEMPS A FEW...TO SEVERAL DEG BELOW NORMAL ACROSS THE CENTRAL AND NW MTNS GIVEN CLOUDIER SKIES AND AFTERNOON PRECIPITATION. THE UNSEASONABLY LOW HEIGHTS WILL COVER THE OHIO VALLEY AND WESTERN PA ON SATURDAY...A PATTERN FAVORABLE FOR DIURNAL CONVECTION GIVEN COOL TEMPS ALOFT/STEEP LAPSE RTS. WILL MAINTAIN LIKELY POPS FOR PM SHRA/TSRA ACROSS THE WESTERN COUNTIES BASED ON LATEST 00Z/03Z GEFS AND SREF GUIDANCE. ENS MEAN 925MB TEMPS INDICATE SAT WILL BE ANOTHER WARM DAY ACROSS THE EASTERN HALF OF THE STATE...WHILE CLOUDS/PRECIP KEEP READINGS COOLER ACROSS THE WEST. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... THE SLOW MOVING UPPER TROUGH THAT IS EXPECTED TO DEVELOP AND LINGER OVER THE EASTERN US IS FORCING ONE OF THOSE RARE FORECASTS FROM THE DEPARTMENT OF REDUNDANCY DEPARTMENT. DAILY MENTION OF SHOWERS AND STORMS WILL SOUND TEDIOUS AND REPETITIVE IN THE FORECAST...BUT THERE ISN`T A PERIOD THROUGH THE WHOLE OF NEXT WEEK WHEN THERE SEEMS LIKE THE REGION WILL NOT SEE AT LEAST SCATTERED SHOWERS OR STORMS. TEMPERATURES WILL AVERAGE NEAR TO SLIGHTLY BELOW NORMAL GIVEN THE EXPECTED LOWER THAN NORMAL UPPER HEIGHTS...CLOUD COVER AND EXPECTED PRECIPITATION CHANCES. THE ANOMALOUS UPPER TROUGH IS EXPECTED TO SLOWLY RETROGRADE NEXT WEEK...WITH HINTS THAT THE THE BERMUDA RIDGE WILL EXPERIENCE A RESURGENCE INTO THE EASTERN US TOWARD NEXT WEEKEND...HINTING AT A WARMER BUT STILL STILL HUMID AIRMASS TO RETURN TO THE REGION. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... BANDS OF SHOWERS AND STORMS WILL CONTINUE INTO THE MID EVENING HOURS...IF NOT LONGER. TEMPS ALOFT COOLER THAN YESTERDAY...AND STORMS HIGHER...THUS MORE OF A HAIL THREAT TODAY. ALSO A WIND THREAT...AS WAS THE CASE YESTERDAY. LATER TONIGHT...EXPECT FOG TO BECOME THE MAIN CONCERN. NOT MUCH CHANGE EXPECTED INTO EARLY NEXT WEEK...AS A LARGE UPPER LEVEL TROUGH WILL REMAIN OVER THE EASTERN U.S. INTO THE WEEKEND...BEFORE MIGRATING SLOWLY WESTWARD INTO THE MIDWEST AND PLAINS DURING THE FIRST WEEK OF JULY. THIS WILL RESULT IN A PROLONGED PERIOD OF UNSETTLED CONDITIONS WITH DAILY CHANCES FOR SCT SHOWERS AND THUNDERSTORMS. FOG WILL ALSO BE LIKELY A FEW HOURS EITHER SIDE OF SUNRISE. OUTLOOK... SUN-WED...VFR-MVFR WITH SCT SHOWERS AND TSTMS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/LA CORTE/STEINBUGL NEAR TERM...DEVOIR/FITZGERALD SHORT TERM...LAMBERT LONG TERM...LA CORTE/LAMBERT AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS AMARILLO TX
554 PM CDT FRI JUN 28 2013 .AVIATION... VFR CONDITIONS TO PREVAIL THROUGH THIS TAF ISSUANCE. NORTHWEST UPPER LEVEL FLOW WILL KEEP THE RISK OF CONVECTION IN AND AROUND THE TERMINAL BOTH THIS EVENING AND TOMORROW AFTERNOON. CONVECTIVE CHANCES AT THE TERMINALS THIS EVENING REMAIN TOO LOW TO INSERT INTO PREVAILING GROUPS AND WILL BE DEPENDENT ON CONVECTION OVER NEW MEXICO PERSISTING INTO THE PANHANDLES. WILL CONTINUE TO CLOSELY MONITOR THE CONVECTIVE TRENDS AND WILL MAKE UPDATES AS NEEDED. TOMORROWS CHANCES LOOK HIGHER THAN TODAYS BUT ARE AT THE VERY END OF THIS TAF ISSUANCE. && .PREV DISCUSSION... /ISSUED 348 PM CDT FRI JUN 28 2013/ SHORT TERM... AFTERNOON WV SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOWS THE LARGE UPPER RIDGE SQUARELY CENTERED OVER THE FOUR CORNERS REGION. WHILE THIS RIDGE WILL LIKELY BRING RECORD HEAT TO THE WESTERN CONUS...THE PLACEMENT OF THIS RIDGE MEANS THE PANHANDLES WILL SEE A SHIFT TOWARD WETTER AND COOLER WX CONDITIONS. MEANWHILE THE COLD FRONT THAT PUSHED THROUGH THE AREA LAST NIGHT HAS SLID INTO SOUTHERN TX. EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW RESULTED IN COOLER CONDITIONS ALTHOUGH ITS STILL TOASTY WITH TEMPS THIS AFTERNOON CLIMBING WELL INTO THE 90S. CONVECTION HAS STARTED TO DEVELOP OVER THE HIGHER TERRAIN IN NM AND CO WHICH IS TYPICAL IN THIS TYPE OF WX PATTERN. HOWEVER GIVEN THAT THE UPPER FLOW IS MORE NORTH- NORTHEASTERLY STORMS WILL HAVE A TOUGH TIME MAKING IT INTO THE WESTERN TX PANHANDLES. ALTHOUGH INSTABILITY IS IN PLACE ACROSS THE AREA /PER SPC MESOSCALE ANALYSIS SHOWING AROUND 1000-1500 J/KG SBCAPE VALUES/ BULK SHEAR IS WEAK SO IF ANY STORMS DO MAKE IT INTO THE NORTHWESTERN ZONES THEY WILL NOT BE ORGANIZED. HOWEVER PRECIP CHANCES IMPROVE SAT AS AN UPPER TROUGH OVER THE GREAT LAKES REGION RETROGRADES INTO THE MIDWEST WHILE THE WESTERN CONUS RIDGE EDGES A BIT FURTHER TO THE WEST. EXPECT THE UPPER FLOW TO TRANSITION MORE TO THE NORTHWEST WHICH WOULD FAVOR A GREATER COVERAGE OF STORMS. STORMS MAY BE MORE ORGANIZED AS WELL OWING TO LARGER VALUES OF CAPE AND SHEAR. ALTHOUGH SPC HAS KEPT THE AREA OUT OF A SLIGHT RISK FOR SEVERE STORMS LIKELY DUE TO A LACK OF ANY APPRECIABLE CONVECTIVE INITIATION MECHANISM...LARGE HAIL AND DAMAGING WIND GUSTS WILL BE THE MAIN THREATS. LONG TERM... THE UPPER TROUGH CONTINUES TO RETROGRADE TOWARD THE OH VALLEY EARLY NEXT WEEK WHILE THE UPPER RIDGE REMAINS OVER THE WESTERN CONUS. THE PANHANDLES WILL REMAIN UNDER STOUT NORTHERLY UPPER FLOW ALTHOUGH AT TIMES...ESPECIALLY EARLY ON IN THE WEEK...PRECIP CHANCES MAY BE LIMITED DUE TO A MORE NORTHERLY COMPONENT ALOFT. BY WEDNESDAY AND ESPECIALLY INDEPENDENCE DAY...PRECIP CHANCES LOOK BETTER AS THE UPPER TROUGH MOVES INTO THE CENTRAL PLAINS WHILE THE UPPER FLOW BACKS TOWARD THE NORTHWEST. THIS PATTERN LOOKS LIKE IT WILL HOLD TOWARD THE END OF THE WEEK. GIVEN MEDIUM RANGE MODELS HAVE NOT DIVERGED TOO MUCH FROM THEIR SOLUTIONS HAVE OPTED TO NOT MAKE TOO MANY CHANGES FOR THIS PERIOD. BESIDES THE INCREASED RAIN CHANCES...TEMPS WILL CONTINUE TO COOL WITH HIGHS MAINLY IN THE 80S EXPECTED AREA WIDE. THIS WILL BE A NICE CONTRAST TO THE HOT WEEK WE`VE HAD. CLK FIRE WEATHER... NEITHER ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED OVER THE NEXT SEVERAL DAYS DUE TO MINIMUM RELATIVE HUMIDITY VALUES ABOVE 20 PERCENT...PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS...AND 20 FOOT WINDS GENERALLY STAYING UNDER 15 MPH. CLK && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 14/02
AREA FORECAST DISCUSSION
NWS AMARILLO TX
348 PM CDT FRI JUN 28 2013 .SHORT TERM... AFTERNOON WV SATELLITE IMAGERY AND RUC UPPER AIR ANALYSIS SHOWS THE LARGE UPPER RIDGE SQUARELY CENTERED OVER THE FOUR CORNERS REGION. WHILE THIS RIDGE WILL LIKELY BRING RECORD HEAT TO THE WESTERN CONUS...THE PLACEMENT OF THIS RIDGE MEANS THE PANHANDLES WILL SEE A SHIFT TOWARD WETTER AND COOLER WX CONDITIONS. MEANWHILE THE COLD FRONT THAT PUSHED THROUGH THE AREA LAST NIGHT HAS SLID INTO SOUTHERN TX. EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW RESULTED IN COOLER CONDITIONS ALTHOUGH ITS STILL TOASTY WITH TEMPS THIS AFTERNOON CLIMBING WELL INTO THE 90S. CONVECTION HAS STARTED TO DEVELOP OVER THE HIGHER TERRAIN IN NM AND CO WHICH IS TYPICAL IN THIS TYPE OF WX PATTERN. HOWEVER GIVEN THAT THE UPPER FLOW IS MORE NORTH- NORTHEASTERLY STORMS WILL HAVE A TOUGH TIME MAKING IT INTO THE WESTERN TX PANHANDLES. ALTHOUGH INSTABILITY IS IN PLACE ACROSS THE AREA /PER SPC MESOSCALE ANALYSIS SHOWING AROUND 1000-1500 J/KG SBCAPE VALUES/ BULK SHEAR IS WEAK SO IF ANY STORMS DO MAKE IT INTO THE NORTHWESTERN ZONES THEY WILL NOT BE ORGANIZED. HOWEVER PRECIP CHANCES IMPROVE SAT AS AN UPPER TROUGH OVER THE GREAT LAKES REGION RETROGRADES INTO THE MIDWEST WHILE THE WESTERN CONUS RIDGE EDGES A BIT FURTHER TO THE WEST. EXPECT THE UPPER FLOW TO TRANSITION MORE TO THE NORTHWEST WHICH WOULD FAVOR A GREATER COVERAGE OF STORMS. STORMS MAY BE MORE ORGANIZED AS WELL OWING TO LARGER VALUES OF CAPE AND SHEAR. ALTHOUGH SPC HAS KEPT THE AREA OUT OF A SLIGHT RISK FOR SEVERE STORMS LIKELY DUE TO A LACK OF ANY APPRECIABLE CONVECTIVE INITIATION MECHANISM...LARGE HAIL AND DAMAGING WIND GUSTS WILL BE THE MAIN THREATS. .LONG TERM... THE UPPER TROUGH CONTINUES TO RETROGRADE TOWARD THE OH VALLEY EARLY NEXT WEEK WHILE THE UPPER RIDGE REMAINS OVER THE WESTERN CONUS. THE PANHANDLES WILL REMAIN UNDER STOUT NORTHERLY UPPER FLOW ALTHOUGH AT TIMES...ESPECIALLY EARLY ON IN THE WEEK...PRECIP CHANCES MAY BE LIMITED DUE TO A MORE NORTHERLY COMPONENT ALOFT. BY WEDNESDAY AND ESPECIALLY INDEPENDENCE DAY...PRECIP CHANCES LOOK BETTER AS THE UPPER TROUGH MOVES INTO THE CENTRAL PLAINS WHILE THE UPPER FLOW BACKS TOWARD THE NORTHWEST. THIS PATTERN LOOKS LIKE IT WILL HOLD TOWARD THE END OF THE WEEK. GIVEN MEDIUM RANGE MODELS HAVE NOT DIVERGED TOO MUCH FROM THEIR SOLUTIONS HAVE OPTED TO NOT MAKE TOO MANY CHANGES FOR THIS PERIOD. BESIDES THE INCREASED RAIN CHANCES...TEMPS WILL CONTINUE TO COOL WITH HIGHS MAINLY IN THE 80S EXPECTED AREA WIDE. THIS WILL BE A NICE CONTRAST TO THE HOT WEEK WE`VE HAD. CLK && .FIRE WEATHER... NEITHER ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED OVER THE NEXT SEVERAL DAYS DUE TO MINIMUM RELATIVE HUMIDITY VALUES ABOVE 20 PERCENT...PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS...AND 20 FOOT WINDS GENERALLY STAYING UNDER 15 MPH. CLK && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 67 90 62 85 60 / 10 10 30 20 20 BEAVER OK 66 92 61 85 57 / 10 10 20 10 10 BOISE CITY OK 65 91 61 83 59 / 20 10 30 20 30 BORGER TX 70 94 66 88 64 / 10 10 30 10 20 BOYS RANCH TX 68 96 66 87 63 / 10 10 30 20 30 CANYON TX 65 91 62 85 59 / 10 10 30 20 20 CLARENDON TX 69 93 64 86 61 / 10 10 30 10 20 DALHART TX 64 92 62 84 61 / 20 10 30 20 30 GUYMON OK 65 92 62 86 59 / 20 10 30 10 20 HEREFORD TX 63 93 63 84 58 / 10 10 30 20 30 LIPSCOMB TX 66 92 61 85 59 / 10 10 20 10 10 PAMPA TX 66 90 62 83 59 / 10 10 30 10 20 SHAMROCK TX 68 94 64 85 60 / 10 10 30 10 10 WELLINGTON TX 69 97 65 89 61 / 10 10 30 10 10 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 07/05
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
539 PM EDT FRI JUN 28 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL RESIDE OVER THE EASTERN UNITED STATES THIS WEEKEND. THIS PATTERN WILL RESULT IN A DAILY THREAT OF SHOWERS AND THUNDERSTORMS...WITH SOME POTENTIAL FOR SEVERE STORMS DURING THE AFTERNOONS AND EVENINGS. && .NEAR TERM /THROUGH SATURDAY/... AS OF 530 PM EDT FRIDAY... HAVE KEPT THE SVR THUNDERSTORM WATCH 388 CONTINUING ALTHOUGH SVR THREAT LOOKS TO BE DIMINISHING AS LINE OF STORMS EXITS THE CWA. STILL MESOANALYSIS INDICATES INSTABILITY AND SHEAR SUCH THAT SOME REDEVELOPMENT INTO THE NEXT HOUR OR IS POSSIBLE...PER CHAT WITH SPC. MAY BE ABLE TO CANCEL IT EARLY THOUGH. THE WESTERLY FLOW HOWEVER IS ACTING TO SUPPRESS ANY DEVELOPMENT WEST OF THE PIEDMONT AS CU HAS BEEN MORE OF FAIR WX VARIETY. LOWERED POPS CONSIDERABLY ACROSS THE BOARD WITH HIGHER POPS IN THE SOUTHEAST. THE 18Z NAM/12Z LOCAL WRF AND 20Z HRRR HANDLING THIS SETUP WELL AND GOING INTO THE EVENING LOOKS LIKE FOCUS FOR MORE SHOWERS WILL BE INTO THE NC MTNS/FOOTHILLS AND ACROSS SE WV PORTIONS OF SW VA...ALTHOUGH INSTABILITY SHOULD BE LOWER AND THREAT OF STORMS LOOKS SMALL. MADE CHANGES TO SKY COVER TO ALLOW FOR MORE SUNSHINE THROUGH 7 PM...OUTSIDE OF CONVECTION AREA. PREVIOUS VALID DISCUSSION... VIRTUALLY ALL ACTIVITY SHOULD SUBSIDE BY MIDNIGHT. LOWS WERE ONLY DROPPED A DEGREE OR TWO AS DEWPOINTS SHOULD FALL SLIGHTLY OVERNIGHT...BUT CONCERNS ABOUT DEBRIS CLOUD COVER WILL HOLD OFF DECENT RADIATIONAL COOLING. BY SATURDAY...THE UPPER LEVEL TROUGH WILL BE DIGGING SOUTHWARD OVER THE OHIO RIVER VALLEY. THE WESTERLY FLOW DOES NOT APPEAR TO BE AS STRONG COMPARED TO FRIDAY...AND THE WIND SHEAR PROFILE IS CONSIDERABLY LESS IMPRESSIVE ACCORDING TO ALL MODEL SOUNDINGS. THUS...THE ATMOSPHERIC ENVIRONMENT SUGGESTS LESS ORGANIZED CONVECTION AND MORE PULSE SHOWERS AND THUNDERSTORMS TO POP UP DURING EARLY SATURDAY AFTERNOON. THE MORE ORGANIZED CONVECTION APPEARS TO BE WELL EAST OF THE CWA ACCORDING TO THE SYNOPTIC MODELS. WHILE THE DRIER BOUNDARY LAYER COULD DELAY THE ONSET OF ACTIVITY...THE PRESENCE OF THE UPPER LEVEL TROUGH AND HIGHS REACHING THE UPPER 70S TO THE UPPER 80S SUGGEST THERE IS STILL A POTENTIAL SEVERE THREAT...PARTICULARLY EAST OF THE BLUE RIDGE. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... AS OF 400 PM EDT FRIDAY... AMPLIFIED/BLOCKY PATTERN IN PLACE WITH A TROUGH OVER MUCH OF THE EASTERN CONUS. DISTURBANCES WILL CONTINUE TO ARRIVE FROM THE WEST AND NORTHWEST THROUGH THE WEEKEND...LEADING TO IN AND OUT SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND. SUNDAY SHOULD BE THE WETTEST DAY AS AN UPPER LOW POTENTIALLY CUTS OFF AND RECENTERS OVER THE LOWER OHIO VALLEY AS THE TROUGH STRENGTHENS....AND SURFACE WINDS BACK. MORE SOUTHERLY COMPONENT WILL HELP FOCUS STORMS ALONG THE BLUE RIDGE. WATER PROBLEMS MAY EVENTUALLY DEVELOP WITH SEVERAL DAYS OF THIS PATTERN. WITH MORE CLOUDS AND STORMS THIS WEEKEND...ALSO WITH SLIGHT COOLING AT H85/H7...TEMPS SHOULD BE A SLIGHT COOLING TREND...ALTHOUGH STILL WARM AND HUMID THROUGH THE WEEKEND. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 400 PM EDT FRIDAY... UPPER AIR PATTERN REMAINS WITH SOME RETROGRESSION OF THE BERMUDA HIGH NEXT WEEKEND...PERHAPS FINALLY LEADING TO A DRIER SOLUTION. BEFORE THEN...THE ONLY CHANGE TO THE PATTERN INTO THE MIDDLE OF NEXT WEEK WILL BE THE CLOSING OFF OF AN UPPER RIDGE JUST NW OF BERMUDA. THIS WILL ALLOW SHRTWAVES/JET STREAKS TO TAKE ALMOST A SOUTH TO NORTH PATH OVER OUR REGION...WHICH WILL LEAD TO EVEN MORE WIDESPREAD SHOWERS AND THUNDERSTORMS INTO NEXT WEEK. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... AS OF 150 PM EDT FRIDAY... VFR CONDITIONS WITH GUSTY WESTERLY WINDS WILL PREVAIL THROUGH THIS AFTERNOON. IN ADDITION...SHOWERS AND THUNDERSTORMS WILL POP UP DURING THE NEXT FEW HOURS. WITH SCATTERED CONVECTIVE ACTIVITY LIKELY THROUGHOUT THE AREA...VCTS WAS KEPT AT ALL TAF SITES. THE SHOWERS AND THUNDERSTORM SHOULD SUBSIDE BY SUNSET...AND WINDS WILL ALSO DECREASE. THE MODEL GUIDANCE IS NOT REALLY PESSIMISTIC ABOUT FOG AND STRATUS TONIGHT...SO ONLY A PERIOD OF MVFR FOG WAS MENTIONED AT BLF/LWB/BCB...BUT ROA/LYH/DAN WAS LEFT AT VFR. WINDS WILL NOT BE AS GUSTY DURING SATURDAY. HOWEVER...THE DAILY THREAT FOR AFTERNOON TO EVENING SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE WEEKEND INTO EARLY NEXT WEEK COURTESY OF AN UPPER LEVEL TROUGH OVER THE OHIO RIVER VALLEY. VFR CONDITIONS SHOULD BE PRESENT DURING THE MORNINGS...WITH SOME POTENTIAL FOR MVFR IN THE SHOWERS AND THUNDERSTORMS...AND MAYBE A LITTLE FOG OR STRATUS IN SHELTERED AREAS OVERNIGHT. BY THE MIDDLE OF NEXT WEEK...THE UPPER LEVEL TROUGH WILL SHIFT WESTWARD...AS A STRONG UPPER LEVEL RIDGE BUILDS OVER THE EAST COAST. THUS...THE COVERAGE IN DIURNAL CONVECTIVE ACTIVITY MAY GRADUALLY WANE WITH TIME. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PW NEAR TERM...PW/WP SHORT TERM...KM LONG TERM...KM AVIATION...PW
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1100 AM PDT Fri Jun 28 2013 .SYNOPSIS... Temperatures across the Inland Northwest will warm over the weekend and reach very hot temperatures early next week. There will be a small chance of strong thunderstorms Saturday over the Idaho Panhandle. Temperatures Monday through Wednesday will be some of the hottest we have seen in several years. Many places will experience triple digit heat early next week. && .DISCUSSION... A very minor forecast update sent out mainly to put in clear skies across much of the region except for over the Cascades and across the northern mountains. The rest of the forecast remains on track. latest 12Z model guidance still supports developing thunderstorms over the Cascades, mainly near the crest. We will start out with a little bit of a cap across these areas, but the higher peaks are expected to break through. Once (if) the cap is broken, there is a convective potential of up to around 700 J/KG to be tapped into and strong shear of around 40 to 50 kts between 0-6 km. These parameters would support the possibility for storms going severe. The problem with seeing any severe thunderstorms today, is that the only kicker in town to provide additional synoptic lift is still too far offshore to have any effect on thunderstorms today. This means that the only lift we will generate will be from thermodynamics of the atmosphere (aka buoyancy relationships). It may take much of this afternoon before storms can get going as well with only a few hours of really good buoyancy during our peak heating. The NAM appears to be overdoing our dew point temps over the mountains, so the GFS is being relied upon much more for convective potential. Although we will see a considerable amount of CAPE over the Northeast Blue Mountains into the Central Panhandle Mountains today, there also looks to be a stronger cap in place of around 50-100 J/KG; thus, we will continue to go with clear skies across these areas. The SREF supports thunderstorms only over the Cascade Mountains this afternoon as well. The HRRR model would suggest no thunderstorms across the region today, so there is some uncertainty when consulting some of the high resolution short term model guidance. /SVH && .AVIATION... 18Z TAFS: A strong ridge building in from the south will promote mostly clear skies across much of the region into this evening. Some developing cumulus is expected over the northern WA Cascade Mtns and across the northern mtns of NE WA and N ID near the Canadian border. Cumulus over the northern WA Cascades may be able to break the capping inversion this afternoon for isolated thunderstorms across the higher peaks near the crest, but any storms that do develop are not expected to impact the KEAT taf site. The focus for tonight will be for the potential for some elevated thunderstorms pushing into the region from the south. There is still some uncertainty with the coverage thunderstorms, but all taf sites could be impacted. Thunderstorm threat for KLWS, KPUW, KMWH and KEAT is expected to hold off until about 09Z and then for KGEG, KSFF and KCOE a few hours later after 12Z. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 87 63 89 65 90 68 / 0 10 20 20 10 0 Coeur d`Alene 87 60 89 62 89 65 / 0 10 20 20 10 0 Pullman 89 59 88 61 89 65 / 0 20 20 20 10 10 Lewiston 95 67 95 69 97 69 / 0 20 20 20 10 10 Colville 88 57 92 60 93 63 / 10 10 20 20 10 0 Sandpoint 83 53 89 58 88 59 / 0 0 20 20 10 0 Kellogg 85 60 88 62 87 64 / 10 10 20 30 10 0 Moses Lake 92 65 93 66 97 68 / 0 20 20 10 0 0 Wenatchee 91 68 92 68 96 71 / 0 10 20 10 0 0 Omak 89 62 91 63 96 66 / 0 10 20 10 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
946 AM PDT Fri Jun 28 2013 .SYNOPSIS... Temperatures across the Inland Northwest will warm over the weekend and reach very hot temperatures early next week. There will be a small chance of strong thunderstorms Saturday over the Idaho Panhandle. Temperatures Monday through Wednesday will be some of the hottest we have seen in several years. Many places will experience triple digit heat early next week. && .DISCUSSION... A very minor forecast update sent out mainly to put in clear skies across much of the region except for over the Cascades and across the northern mountains. The rest of the forecast remains on track. latest 12Z model guidance still supports developing thunderstorms over the Cascades, mainly near the crest. We will start out with a little bit of a cap across these areas, but the higher peaks are expected to break through. Once (if) the cap is broken, there is a convective potential of up to around 700 J/KG to be tapped into and strong shear of around 40 to 50 kts between 0-6 km. These parameters would support the possibility for storms going severe. The problem with seeing any severe thunderstorms today, is that the only kicker in town to provide additional synoptic lift is still too far offshore to have any effect on thunderstorms today. This means that the only lift we will generate will be from thermodynamics of the atmosphere (aka buoyancy relationships). It may take much of this afternoon before storms can get going as well with only a few hours of really good buoyancy during our peak heating. The NAM appears to be overdoing our dew point temps over the mountains, so the GFS is being relied upon much more for convective potential. Although we will see a considerable amount of CAPE over the Northeast Blue Mountains into the Central Panhandle Mountains today, there also looks to be a stronger cap in place of around 50-100 J/KG; thus, we will continue to go with clear skies across these areas. The SREF supports thunderstorms only over the Cascade Mountains this afternoon as well. The HRRR model would suggest no thunderstorms across the region today, so there is some uncertainty when consulting some of the high resolution short term model guidance. /SVH && .AVIATION... 12Z TAFS: A strong ridge building in from the south will keep dry conditions over the area today. There is a possibility for isolated thunderstorms over the North WA Cascades btwn 20z-03z but this should not impact KEAT. An increase in mid level moisture/instability arrives after 06z Saturday with elevated thunderstorms possibility developing around KMWH/KPUW/KLWS. For KGEG/KSFF/KCOE the best chances for thunderstorms will hold off til after 12z Sat. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 87 63 89 65 90 68 / 0 10 20 20 10 0 Coeur d`Alene 87 60 89 62 89 65 / 0 10 20 20 10 0 Pullman 89 59 88 61 89 65 / 0 20 20 20 10 10 Lewiston 95 67 95 69 97 69 / 0 20 20 20 10 10 Colville 88 57 92 60 93 63 / 10 10 20 20 10 0 Sandpoint 83 53 89 58 88 59 / 0 0 20 20 10 0 Kellogg 85 60 88 62 87 64 / 10 10 20 30 10 0 Moses Lake 92 65 93 66 97 68 / 0 20 20 10 0 0 Wenatchee 91 68 92 68 96 71 / 0 10 20 10 0 0 Omak 89 62 91 63 96 66 / 0 10 20 10 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
218 PM CDT FRI JUN 28 2013 .SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT) ISSUED AT 218 PM CDT FRI JUN 28 2013 WATER VAPOR IMAGERY/RAP 500MB ANALYSIS SHOWS A CLOSED LOW NEAR THE LAKE HURON/EERIE REGION WITH A TROUGH EXTENDING WESTWARD ACROSS LOWER MI INTO NORTHERN WI/MN. RAP ANALYZING SEVERAL EMBEDDED POSITIVE VORTICITY MAXIMA WITHIN THIS TROUGH...ADVECTING SOUTHWARD ACROSS THE AREA. THIS TROUGH/VORTICITY...COMBINED WITH FAIRLY STEEP LOWER LEVEL LAPSE RATES WAS PRODUCING SCATTERED SHOWER ACTIVITY MAINLY EAST OF THE MISSISSIPPI RIVER. OTHERWISE...AN EXTENSIVE CUMULUS FIELD WAS NOTED ACROSS THE REGION UNDER THE COOLER CYCLONIC FLOW ALOFT WITH SURFACE TEMPERATURES RANGING FROM THE 65-70 DEGREES ACROSS NORTHERN WI...TO THE NEAR 80 ACROSS NORTHEAST IA/FAR SOUTHWEST WI. IN ADDITION...BREEZY NORTHWEST WINDS MAKING IT FEEL LIKE MORE OF AN EARLY AUTUMN DAY ACROSS THE REGION. LOOK FOR THE MID-LEVEL TROUGH TO CONTINUE DROPPING SOUTHWARD ACROSS THE AREA TONIGHT...PRODUCING EXTENSIVE CLOUD COVER AND SCATTERED SHOWER ACTIVITY. LOWS OVERNIGHT EXPECTED TO DROP OFF INTO THE UPPER 50S TO THE LOWER 60S. COOLER CYCLONIC FLOW TO CONTINUE ACROSS THE AREA ON SATURDAY. THUS...ANOTHER DAY OF ABUNDANT CLOUD COVER AND SCATTERED SHOWERS CAN BE EXPECTED. AN ISOLATED RUMBLE OF THUNDER MAY ALSO OCCUR AS 0-1KM ML MUCAPE PERKS UP INTO THE 400-1000J/KG RANGE BY AFTERNOON. BAY LATER IN THE AFTERNOON...EXPECTING MOST OF THE CONVECTION TO BE CONFINED SOUTH MAINLY SOUTH OF I-94 AS THE MID-LEVEL TROUGH AXIS DROPS FARTHER SOUTH INTO IA/IL AND RIDGING STARTS TO BUILD ACROSS THE NORTH. OTHERWISE...PLAN ON TEMPERATURES TO BE A COUPLE DEGREES COOLER THAN FRIDAY...TOPPING OFF IN THE 70-75 RANGE. THE MID-LEVEL TROUGH WILL CONTINUE TO ROTATE SOUTH OF THE AREA SATURDAY NIGHT WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN PLAINS/MN. AS A RESULT...LOOK FOR A RAPID DIMINISHING OF SHOWER ACTIVITY ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA WITH CLEARING SKIES FROM NORTH TO SOUTH AS THE EVENING PROGRESSES. MOSTLY CLEAR SKIES WILL THEN BE NOTED OVERNIGHT WITH TEMPERATURES COOLING INTO THE UPPER 40S TO THE MIDDLE 50S. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 218 PM CDT FRI JUN 28 2013 PATTERN REMAINS BASICALLY UNCHANGED FROM SUNDAY THROUGH TUESDAY NIGHT WITH THE MID-LEVEL TROUGH AXIS EXTENDING FROM THE GREAT LAKES TO TO THE OHIO RIVER VALLEY WHILE RIDGE OF HIGH PRESSURE CONTROLS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER REGIONS. THIS KEEPS THE AREA DRY WITH TEMPERATURES REMAINING A FEW DEGREES BELOW NORMAL. PLAN ON HIGHS IN THE MID/UPPER 70S WITH OVERNIGHT LOWS IN THE 50S. IT APPEARS THE GFS/ECMWF EVENTUALLY SHOW THE MID-LEVEL TROUGH FILLING/LIFTING NORTHEAST INTO THE EASTERN GREAT LAKES/EASTERN ONTARIO BY FRIDAY WITH FLOW BECOMING MORE LAMINAR/HIGH ZONAL ACROSS CANADA. SO...LOOKS LIKE A SLIGHT CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS WEDNESDAY AND THURSDAY WITH FRIDAY DRY AND BECOMING WARMER. PLAN ON HIGHS IN THE UPPER 70S ON WEDNESDAY... WARMING INTO THE 80-85 DEGREE RANGE BY FRIDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1206 PM CDT FRI JUN 28 2013 SCATTERED SHOWERS HAVE DEVELOPED THIS MORNING...MAINLY ACROSS WISCONSIN. THESE SHOWERS HAVE DROPPED THE VISIBILITY BRIEFLY INTO THE MVFR RANGE. AS THESE MOVE SOUTH...APPEARS THEY HAVE THE BEST POTENTIAL TO IMPACT KLSE...SO HAVE INCLUDED A TEMPO GROUP FOR THE EARLY AFTERNOON TO SHOW THE POSSIBILITY OF THE SHOWERS GOING OVER THE AIRFIELD WITH A REDUCTION TO THE VISIBILITY. ONCE THE INITIAL WAVE OF SHOWERS GOES BY...CONFIDENCE ON HOW THE REMAINDER OF THE AFTERNOON AND EVENING WILL TURN OUT BECOMES PRETTY LOW. THE 28.15Z RAP SHOWS THE CYCLONIC FLOW ALOFT WILL CONTINUE INTO TONIGHT WHICH WILL HELP TO MAINTAIN THE CLOUDS OVER THE AREA. SHOULD BE ADDITIONAL SHORT WAVE TROUGHS IN THIS FLOW...BUT THEY WILL PRODUCE VERY LITTLE PVA ADVECTION AND THUS NOT SURE HOW MANY ADDITIONAL SHOWERS WILL BE AROUND. THE RAP...28.14Z ARX LAPS AND 28.12Z NAM ALL TRY TO SHOW ANOTHER ROUND OF SHOWERS COMING OFF LAKE SUPERIOR OVERNIGHT AND MAINLY IMPACTING MINNESOTA AND IOWA AS THEY COME SOUTH. WILL MAINTAIN THE MENTION OF VCSH THROUGH THE NIGHT TO ACCOUNT FOR THIS AND LET LATER FORECASTS DETAIL THIS THREAT BETTER IF THESE SHOWERS DO DEVELOP. ALSO SOME POTENTIAL FOR MVFR CEILINGS AS THESE ARE CURRENTLY OVER NORTHERN WISCONSIN. THESE HAVE BEEN MOVING SOUTH AND HAVE INCLUDED THEM FROM THE EARLY EVENING THROUGH THE OVERNIGHT. WILL HAVE TO MONITOR THE SOUTHWARD PROGRESS AND UPDATE IF THEY LOOK TO MOVE IN SOONER. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...04