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


AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1040 AM EDT Mon Aug 6 2012 .NEAR TERM [Through Tonight]... Updated at: 1035am The main updates this morning were based on a forecast of a rainy and cloudy day over much of the area. PoPs were bumped up to categorical in the morning hours where a large area of rain is located (centered roughly near Lake Seminole). Hourly temperatures were trended towards the RAP which seemed to initialize quite well the location of the area of rain as well as the low and mid-level circulations associated with the lingering tropical wave. This resulted in high temperatures that were cooler than the previous forecast - in the mid 80s in many areas - and that may even be a stretch in areas like Marianna and Bainbridge which could very well see rain and dense cloud cover for much of the daytime hours. Therefore, the trends in temperature will be closely monitored in the event another update is warranted. The only other change was to add heavy rain wording into the areas with highest PoPs. Our 12z TAE sounding showed very high PWATs around 2.33", which is close to 130% of normal. Combined with light flow, moist adiabatic lapse rates, and very deep warm cloud depth over 14,000 feet - the ingredients are all there for any showers or storms to be efficient rainfall producers. Bias flags already inidicate that some of the area radars are underestimating the rain rates in this tropical environment, so areas that receive persistent heavy rainfall will need to be closely monitored for localized flooding potential. Given 3-hr BiasHPE rain estimates already close to FFG in some areas, and 1-hr values up to 60% of FFG in the areas of heavier rain, it is certainly within the realm of possibility that additional rain today will lead to a few spots of flooding. This threat will be added to the HWO. We could very well see a repeat of yesterday to the east of the circulation center of the tropical wave, just displaced slightly further west to account for the westward drift of the wave. Yesterday there was a substantial amount of deep convection and thunderstorms that formed near the I-75 corridor in Florida near a low-level convergence zone. It appears that a similar band of deep convection is beginning to form from near K40J to the south into offshore areas. This could affect the eastern portions of our forecast area today, from CTY/40J north to near VLD, TMA, FZG. && .SHORT TERM [Tuesday Through Wednesday]... On Tuesday we will still be dealing with the passing trough mentioned above, and will likely have another waiting in the wings across eastern Florida. In addition to the surface features, the upper level trough will expand into the Southeast, providing a bit more synoptic scale forcing for ascent. These combined will keep rain chances well above average on Tuesday, and high temperatures near or just below average. By Wednesday, the surface subtropical ridge will begin to nose back in from the east and start to shunt the pesky tropical waves out of the local area. However, it won`t be until late in the day that the ridge will take hold, and the upper level trough will remain in place, so we will probably still have plenty of shower and thunderstorm activity across our western forecast area. Thus, rain chances will remain above average in those locations on Wednesday. && .LONG TERM [Wednesday Night through Sunday]... Not much change from the previous extended package, as our very atypical summer governed by an unusually steep Upper Level Trof down the eastern seaboard will continue through the bulk of the period. This "disturbed pattern" combined with onshore SW flow at lower levels, and plenty of deep layer Tropical Moisture will keep rain chances elevated and daytime high temperatures near or slightly below climo. By the very end of the period (Sunday and Monday), we could see some slight improvements to the current fcst as the Trof tries to exit off to the E, but the deep layer moisture might very well remain entrenched over the region due to very weak forcing, so PoPs could still remain elevated. Therefore, will likely need to see a few more model cycles before confidence is high enough to make a final determination. && .AVIATION [Beginning 12Z Monday]... With plenty of deep layer moisture combined with a weak low-mid level circulation moving slowly westward through the CWA today, low clouds, showers, and thunderstorms will be sct to widespread at the terminals. With the weakly defined "center" of this circulation over central portions of the CWA as of early this morning, the best chances for rain will be at TLH, ABY, DHN, and ECP, with rainfall already ongoing at TLH and and ABY. VLD has temporarily cleared out, which should hold off the convection until later this morning or early this afternoon, but this clearing may also allow for a 1-2 hr period of Low Cigs and Vis between 12 and 14 UTC. Overall, expect prevailing MVFR to IFR conditions at most of the Taf sites with the with periods of VFR conditions possible outside of the convection. && .MARINE... Showers and thunderstorms will be possible over the next couple of days as a series of weak tropical waves traverse our waters from southeast to northwest. Winds and seas will remain below headline criteria through the period. However, winds will briefly rise to near cautionary levels as the subtropical ridge noses back in over our coastal waters Tuesday through Wednesday. Additionally, swells from Tropical Storm Ernesto will enhance seas beginning on Wednesday, especially over our western waters. && .FIRE WEATHER... A generally wet and disturbed pattern will continue across the Tri-State area for much if not all of the upcoming week. This will keep afternoon relative humidities well above critical thresholds through the period. && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Lamers SHORT TERM...Harrigan LONG TERM...Gould AVIATION...Gould MARINE...Harrigan FIRE WEATHER...Gould
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1028 AM EDT Mon Aug 6 2012 .NEAR TERM [Through Tonight]... Updated at: 1025am The main updates this morning were based on a forecast of a rainy and cloudy day over much of the area. PoPs were bumped up to categorical in the morning hours where a large area of rain is located (centered roughly near Lake Seminole). Hourly temperatures were trended towards the RAP which seemed to initialize quite well the location of the area of rain as well as the low and mid-level circulations associated with the lingering tropical wave. This resulted in high temperatures that were cooler than the previous forecast - in the mid 80s in many areas - and that may even be a stretch in areas like Marianna and Bainbridge which could very well see rain and dense cloud cover for much of the daytime hours. Therefore, the trends in temperature will be closely monitored in the event another update is warranted. The only other change was to add heavy rain wording into the areas with highest PoPs. Our 12z TAE sounding showed very high PWATs around 2.33", which is close to 130% of normal. Combined with light flow, moist adiabatic lapse rates, and very deep warm cloud depth over 14,000 feet - the ingredients are all there for any showers or storms to be efficient rainfall producers. Bias flags already inidicate that some of the area radars are underestimating the rain rates in this tropical environment, so areas that receive persistent heavy rainfall will need to be closely monitored for localized flooding potential. Given 3-hr BiasHPE rain estimates already close to FFG in some areas, and 1-hr values up to 60% of FFG in the areas of heavier rain, it is certainly within the realm of possibility that additional rain today will lead to a few spots of flooding. This threat will be added to the HWO. && .SHORT TERM [Tuesday Through Wednesday]... On Tuesday we will still be dealing with the passing trough mentioned above, and will likely have another waiting in the wings across eastern Florida. In addition to the surface features, the upper level trough will expand into the Southeast, providing a bit more synoptic scale forcing for ascent. These combined will keep rain chances well above average on Tuesday, and high temperatures near or just below average. By Wednesday, the surface subtropical ridge will begin to nose back in from the east and start to shunt the pesky tropical waves out of the local area. However, it won`t be until late in the day that the ridge will take hold, and the upper level trough will remain in place, so we will probably still have plenty of shower and thunderstorm activity across our western forecast area. Thus, rain chances will remain above average in those locations on Wednesday. && .LONG TERM [Wednesday Night through Sunday]... Not much change from the previous extended package, as our very atypical summer governed by an unusually steep Upper Level Trof down the eastern seaboard will continue through the bulk of the period. This "disturbed pattern" combined with onshore SW flow at lower levels, and plenty of deep layer Tropical Moisture will keep rain chances elevated and daytime high temperatures near or slightly below climo. By the very end of the period (Sunday and Monday), we could see some slight improvements to the current fcst as the Trof tries to exit off to the E, but the deep layer moisture might very well remain entrenched over the region due to very weak forcing, so PoPs could still remain elevated. Therefore, will likely need to see a few more model cycles before confidence is high enough to make a final determination. && .AVIATION [Beginning 12Z Monday]... With plenty of deep layer moisture combined with a weak low-mid level circulation moving slowly westward through the CWA today, low clouds, showers, and thunderstorms will be sct to widespread at the terminals. With the weakly defined "center" of this circulation over central portions of the CWA as of early this morning, the best chances for rain will be at TLH, ABY, DHN, and ECP, with rainfall already ongoing at TLH and and ABY. VLD has temporarily cleared out, which should hold off the convection until later this morning or early this afternoon, but this clearing may also allow for a 1-2 hr period of Low Cigs and Vis between 12 and 14 UTC. Overall, expect prevailing MVFR to IFR conditions at most of the Taf sites with the with periods of VFR conditions possible outside of the convection. && .MARINE... Showers and thunderstorms will be possible over the next couple of days as a series of weak tropical waves traverse our waters from southeast to northwest. Winds and seas will remain below headline criteria through the period. However, winds will briefly rise to near cautionary levels as the subtropical ridge noses back in over our coastal waters Tuesday through Wednesday. Additionally, swells from Tropical Storm Ernesto will enhance seas beginning on Wednesday, especially over our western waters. && .FIRE WEATHER... A generally wet and disturbed pattern will continue across the Tri-State area for much if not all of the upcoming week. This will keep afternoon relative humidities well above critical thresholds through the period. && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Lamers SHORT TERM...Harrigan LONG TERM...Gould AVIATION...Gould MARINE...Harrigan FIRE WEATHER...Gould
AREA FORECAST DISCUSSION
NWS GOODLAND KS
418 PM MDT MON AUG 6 2012 .UPDATE... ISSUED AT 415 PM MDT MON AUG 6 2012 UPDATED TO INCLUDE THUNDERSTORM CHANCES IN THE WEST. CONVECTION HAS INITIATED ALONG A SURFACE TROUGH IN NORTHEAST COLORADO. STORM MOTIONS ARE ALMOST DUE SOUTH SO NOT SURE HOW FAR EAST THESE WILL BE ABLE TO MOVE THIS EVENING. FURTHERMORE...DEW POINTS ARE QUITE LOW. FOR THOSE REASONS...LIMITED POPS TO 30 IN THE FAR NORTHWEST AND 20 ELSEWHERE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 236 PM MDT MON AUG 6 2012 THROUGH TONIGHT...SHORTWAVE TROUGH WILL TRANSLATE SOUTHEASTWARD THE NORTHERN PLAINS. STRONGEST FORCING FOR ASCENT WILL REMAIN NORTHEAST OF THE FORECAST AREA. HOWEVER...WITH A SURFACE LOW DEVELOPING ACROSS NORTHEAST COLORADO...DO EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP ACROSS NORTHERN/NORTHEASTERN PORTIONS OF THE FORECAST AREA AFTER 06Z. WILL ALSO NEED TO MONITOR A WEAK AREA OF SURFACE CONVERGENCE JUST TO THE WEST OF THE FORECAST AREA WHERE A SHALLOW CU FIELD CONTINUES TO DEVELOP. LATEST RUNS OF THE HRRR DEVELOP CONVECTION IN THIS AREA WITH A GENERAL EASTWARD/SOUTHEASTWARD MOVEMENT. NOT COMPLETELY SOLD ON THIS SOLUTION SO OPTING TO KEEP POPS OUT OF THE FORECAST FOR NOW. WILL NEED TO MONITOR AND REEVALUATE AS THE AFTERNOON GOES ON. TUESDAY...SLIGHTLY STRONGER SHORTWAVE TROUGH WILL BEGIN TO IMPACT THE REGION DURING THE DAY TUESDAY. WILL LIKELY SEE A LULL IN PRECIP DURING THE MORNING HOURS IN THE WAKE OF THE DEPARTING OVERNIGHT SYSTEM WITH PRECIP CHANCES INCREASING DURING THE AFTERNOON HOURS. DEEP LAYER SHEAR WILL INCREASE TO AROUND 30-35 KTS DURING THE AFTERNOON HOURS WHICH WILL HELP ORGANIZE THUNDERSTORM UPDRAFTS. ONE LIMITING FACTOR WILL BE MINIMAL AVAILABLE INSTABILITY WITH SBCAPE VALUES OF 500-1000 J/KG. POINT SOUNDINGS DO INDICATE AN INVERTED-V STRUCTURE SO WOULD ANTICIPATE GUSTY OUTFLOW WINDS BEING THE PRIMARY THREAT TOMORROW AFTERNOON/EVENING. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 236 PM MDT MON AUG 6 2012 TUESDAY NIGHT-THURSDAY...LARGE SCALE H5 RIDGE WILL AMPLIFY OVER THE NORTHERN ROCKIES THROUGH THE PERIOD...WITH MAIN CONCERN BEING THE CHANCE FOR LINGERING PRECIPITATION OVER PORTIONS OF THE CWA TUESDAY NIGHT WITH PRECIPITATION CHANCES LOOKING TO BE VERY SMALL AFTER THAT LARGE SCALE SUBSIDENCE OVERSPREADS THE AREA WITH DEEP LAYER FLOW ALOFT OUT OF THE NORTH-NORTHWEST KEEPING ANY DEEP MOISTURE RETURN TO THE AREA LIMITED. FOR TUESDAY NIGHT HOWEVER...DIV Q FIELDS SUGGEST LARGE SCALE SUBSIDENCE WILL OVERSPREAD THE CWA AFTER 03Z...WHICH SHOULD BEGIN TO DIMINISH PRECIPITATION POTENTIAL PRETTY QUICKLY OVERNIGHT. WHILE THERE WILL BE LARGE SCALE SUBSIDENCE...THINK THERE WILL BE AT LEAST A SHORT WINDOW FOR PRECIPITATION DURING THE EVENING HOURS...MAINLY ALONG AND SFC TROUGH EXPECTED TO STRETCH FROM FIRSTVIEW TO MCCOOK. WITH MIXED LAYER CINH VALUES FAIRLY HIGH AND AFOREMENTIONED SUBSIDENCE CONFIDENCE IN PRECIPITATION FAIRLY LOW. ALTHOUGH SREF AND GEFS HAVE FAIRLY HIGH PROBABILITIES (>75%) IN EASTERN CWA...DO NOT THINK CONFIDENCE IS HIGH ENOUGH TO GO MORE THAN 20-40 PERCENT CHANCES THROUGH THE EVENING HOURS. AS H5 RIDGE AMPLIFIES AND MUCH DRIER AIR WORKS INTO THE CWA...THINK PRECIP CHANCES WILL REMAIN VERY LOW TO PRACTICALLY NOTHING THROUGH THE REST OF THE PERIOD. SEEMS TO BE A FAIRLY LARGE SPREAD BETWEEN MODELS WITH RESPECT TO HOW WARM THINGS WILL GET ACROSS THE AREA. WHILE GFS IS MUCH COOLER THAN OTHER MODELS AND GIVEN THE OVERALL FLOW PATTERN WOULD NOT BE UNHEARD OF FOR A COOLER AIR MASS TO BACK INTO CWA. THAT BEING SAID...GFS HAS A FAIRLY WELL DOCUMENTED COLD BIAS THIS SUMMER AND THINK OVERALL BIAS CORRECTED VALUES IN THE MID/UPPER 90S LOOK REASONABLE. MUCH DRIER AIR IS EXPECTED TO MOVE INTO THE AREA WEDNESDAY AFTERNOON ALLOWING RH`S TO APPROACH CRITICAL VALUES. OVERALL DO NOT THINK CONDITIONS WILL BE LONG LASTING AND DO NOT PLAN ON ISSUING ANY WATCHES AT THIS POINT AND THINK THE BIGGEST IMPACT OF DRIER AIR MASS WILL BE TO ALLOW TEMPS TO BE RATHER COOL GIVEN LIGHT WINDS/CLEAR SKIES AND DRY AIR. IN THE EXTENDED (FRIDAY-NIGHT-MONDAY)...WHILE MEDIUM RANGE MODELS START THE PERIOD IN REASONABLE AGREEMENT...DIFFERENCES EMERGE FAIRLY QUICKLY IN THE PERIOD WITH RESPECT TO HANDLING OF SHORT WAVE TROUGH MOVES AROUND TOP OF THE AMPLIFIED H5 RIDGE AND WHAT IMPACT...IF ANY THIS TROUGH HAS ON LARGE SCALE RIDGE PATTERN. THESE DIFFERENCES DO NOT LEAD TO A LOT OF CONFIDENCE IN FORECAST FROM SATURDAY ON...AND PLAN ON KEEPING FORECAST NEAR CONSENSUS DATA FOR THE TIME BEING UNTIL A BETTER FAVORED SOLUTION APPEARS...ALTHOUGH THINK WEIGHTING BLENDS A BIT MORE TOWARDS THE ECWMF IS IN ORDER BASED ON THE GEFS DATA. LATEST ECMWF HAS COME IN A BIT COOLER THAN PREVIOUS RUNS AND GIVEN EASTERLY SFC FLOW AND STRONG HIGH AROUND BASE OF SFC HIGH THINK A GENERAL COOLING TREND IS IN ORDER. WITH MOST NIGHTS NOT REALLY BRINGING A CLEAR SIGNAL FOR WARM TEMPS (DENSE CLOUD COVER...STRONG WINDS...ETC) HAVE WORKED THE 3-5 DEGREE COOLER BIAS CORRECTED SOLUTIONS INTO OVERNIGHT LOW FORECASTS WHERE I COULD...TO PICK UP OUR NORMALLY COLDEST SPOTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1152 AM MDT MON AUG 6 2012 EXPECT PRIMARILY VFR CONDITIONS AT KGLD AND KMCK THROUGH THE EFFECTIVE PERIOD. PRIMARY QUESTION MARK WILL CENTER ON WHAT...IF ANY...IMPACT CONVECTION WILL HAVE DURING THE OVERNIGHT HOURS. GUIDANCE CONTINUES TO SUPPORT HIGHER CHANCES FOR CONVECTION AT KMCK SO WILL CONTINUE VCTS MENTION. HAVE ADJUSTED THE TIMING TO BETTER COINCIDE WITH THE HIGHEST LIKELIHOOD OF PRECIP. LEFT MENTION OF PRECIP OUT OF THE KGLD TAF GIVEN THE LOWER PROBABILITY OF A DIRECT IMPACT. WINDS WILL BECOME LIGHT AND VARIABLE LATE TONIGHT THROUGH THE END OF THE EFFECTIVE PERIOD AS A SURFACE TROUGH RESIDES OVER THE AREA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...024 SHORT TERM...FOLTZ LONG TERM...JRM AVIATION...FOLTZ
AREA FORECAST DISCUSSION
NWS GOODLAND KS
237 PM MDT MON AUG 6 2012 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 236 PM MDT MON AUG 6 2012 THROUGH TONIGHT...SHORTWAVE TROUGH WILL TRANSLATE SOUTHEASTWARD THE NORTHERN PLAINS. STRONGEST FORCING FOR ASCENT WILL REMAIN NORTHEAST OF THE FORECAST AREA. HOWEVER...WITH A SURFACE LOW DEVELOPING ACROSS NORTHEAST COLORADO...DO EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP ACROSS NORTHERN/NORTHEASTERN PORTIONS OF THE FORECAST AREA AFTER 06Z. WILL ALSO NEED TO MONITOR A WEAK AREA OF SURFACE CONVERGENCE JUST TO THE WEST OF THE FORECAST AREA WHERE A SHALLOW CU FIELD CONTINUES TO DEVELOP. LATEST RUNS OF THE HRRR DEVELOP CONVECTION IN THIS AREA WITH A GENERAL EASTWARD/SOUTHEASTWARD MOVEMENT. NOT COMPLETELY SOLD ON THIS SOLUTION SO OPTING TO KEEP POPS OUT OF THE FORECAST FOR NOW. WILL NEED TO MONITOR AND REEVALUATE AS THE AFTERNOON GOES ON. TUESDAY...SLIGHTLY STRONGER SHORTWAVE TROUGH WILL BEGIN TO IMPACT THE REGION DURING THE DAY TUESDAY. WILL LIKELY SEE A LULL IN PRECIP DURING THE MORNING HOURS IN THE WAKE OF THE DEPARTING OVERNIGHT SYSTEM WITH PRECIP CHANCES INCREASING DURING THE AFTERNOON HOURS. DEEP LAYER SHEAR WILL INCREASE TO AROUND 30-35 KTS DURING THE AFTERNOON HOURS WHICH WILL HELP ORGANIZE THUNDERSTORM UPDRAFTS. ONE LIMITING FACTOR WILL BE MINIMAL AVAILABLE INSTABILITY WITH SBCAPE VALUES OF 500-1000 J/KG. POINT SOUNDINGS DO INDICATE AN INVERTED-V STRUCTURE SO WOULD ANTICIPATE GUSTY OUTFLOW WINDS BEING THE PRIMARY THREAT TOMORROW AFTERNOON/EVENING. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 236 PM MDT MON AUG 6 2012 TUESDAY NIGHT-THURSDAY...LARGE SCALE H5 RIDGE WILL AMPLIFY OVER THE NORTHERN ROCKIES THROUGH THE PERIOD...WITH MAIN CONCERN BEING THE CHANCE FOR LINGERING PRECIPITATION OVER PORTIONS OF THE CWA TUESDAY NIGHT WITH PRECIPITATION CHANCES LOOKING TO BE VERY SMALL AFTER THAT LARGE SCALE SUBSIDENCE OVERSPREADS THE AREA WITH DEEP LAYER FLOW ALOFT OUT OF THE NORTH-NORTHWEST KEEPING ANY DEEP MOISTURE RETURN TO THE AREA LIMITED. FOR TUESDAY NIGHT HOWEVER...DIV Q FIELDS SUGGEST LARGE SCALE SUBSIDENCE WILL OVERSPREAD THE CWA AFTER 03Z...WHICH SHOULD BEGIN TO DIMINISH PRECIPITATION POTENTIAL PRETTY QUICKLY OVERNIGHT. WHILE THERE WILL BE LARGE SCALE SUBSIDENCE...THINK THERE WILL BE AT LEAST A SHORT WINDOW FOR PRECIPITATION DURING THE EVENING HOURS...MAINLY ALONG AND SFC TROUGH EXPECTED TO STRETCH FROM FIRSTVIEW TO MCCOOK. WITH MIXED LAYER CINH VALUES FAIRLY HIGH AND AFOREMENTIONED SUBSIDENCE CONFIDENCE IN PRECIPITATION FAIRLY LOW. ALTHOUGH SREF AND GEFS HAVE FAIRLY HIGH PROBABILITIES (>75%) IN EASTERN CWA...DO NOT THINK CONFIDENCE IS HIGH ENOUGH TO GO MORE THAN 20-40 PERCENT CHANCES THROUGH THE EVENING HOURS. AS H5 RIDGE AMPLIFIES AND MUCH DRIER AIR WORKS INTO THE CWA...THINK PRECIP CHANCES WILL REMAIN VERY LOW TO PRACTICALLY NOTHING THROUGH THE REST OF THE PERIOD. SEEMS TO BE A FAIRLY LARGE SPREAD BETWEEN MODELS WITH RESPECT TO HOW WARM THINGS WILL GET ACROSS THE AREA. WHILE GFS IS MUCH COOLER THAN OTHER MODELS AND GIVEN THE OVERALL FLOW PATTERN WOULD NOT BE UNHEARD OF FOR A COOLER AIR MASS TO BACK INTO CWA. THAT BEING SAID...GFS HAS A FAIRLY WELL DOCUMENTED COLD BIAS THIS SUMMER AND THINK OVERALL BIAS CORRECTED VALUES IN THE MID/UPPER 90S LOOK REASONABLE. MUCH DRIER AIR IS EXPECTED TO MOVE INTO THE AREA WEDNESDAY AFTERNOON ALLOWING RH`S TO APPROACH CRITICAL VALUES. OVERALL DO NOT THINK CONDITIONS WILL BE LONG LASTING AND DO NOT PLAN ON ISSUING ANY WATCHES AT THIS POINT AND THINK THE BIGGEST IMPACT OF DRIER AIR MASS WILL BE TO ALLOW TEMPS TO BE RATHER COOL GIVEN LIGHT WINDS/CLEAR SKIES AND DRY AIR. IN THE EXTENDED (FRIDAY-NIGHT-MONDAY)...WHILE MEDIUM RANGE MODELS START THE PERIOD IN REASONABLE AGREEMENT...DIFFERENCES EMERGE FAIRLY QUICKLY IN THE PERIOD WITH RESPECT TO HANDLING OF SHORT WAVE TROUGH MOVES AROUND TOP OF THE AMPLIFIED H5 RIDGE AND WHAT IMPACT...IF ANY THIS TROUGH HAS ON LARGE SCALE RIDGE PATTERN. THESE DIFFERENCES DO NOT LEAD TO A LOT OF CONFIDENCE IN FORECAST FROM SATURDAY ON...AND PLAN ON KEEPING FORECAST NEAR CONSENSUS DATA FOR THE TIME BEING UNTIL A BETTER FAVORED SOLUTION APPEARS...ALTHOUGH THINK WEIGHTING BLENDS A BIT MORE TOWARDS THE ECWMF IS IN ORDER BASED ON THE GEFS DATA. LATEST ECMWF HAS COME IN A BIT COOLER THAN PREVIOUS RUNS AND GIVEN EASTERLY SFC FLOW AND STRONG HIGH AROUND BASE OF SFC HIGH THINK A GENERAL COOLING TREND IS IN ORDER. WITH MOST NIGHTS NOT REALLY BRINGING A CLEAR SIGNAL FOR WARM TEMPS (DENSE CLOUD COVER...STRONG WINDS...ETC) HAVE WORKED THE 3-5 DEGREE COOLER BIAS CORRECTED SOLUTIONS INTO OVERNIGHT LOW FORECASTS WHERE I COULD...TO PICK UP OUR NORMALLY COLDEST SPOTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1152 AM MDT MON AUG 6 2012 EXPECT PRIMARILY VFR CONDITIONS AT KGLD AND KMCK THROUGH THE EFFECTIVE PERIOD. PRIMARY QUESTION MARK WILL CENTER ON WHAT...IF ANY...IMPACT CONVECTION WILL HAVE DURING THE OVERNIGHT HOURS. GUIDANCE CONTINUES TO SUPPORT HIGHER CHANCES FOR CONVECTION AT KMCK SO WILL CONTINUE VCTS MENTION. HAVE ADJUSTED THE TIMING TO BETTER COINCIDE WITH THE HIGHEST LIKELIHOOD OF PRECIP. LEFT MENTION OF PRECIP OUT OF THE KGLD TAF GIVEN THE LOWER PROBABILITY OF A DIRECT IMPACT. WINDS WILL BECOME LIGHT AND VARIABLE LATE TONIGHT THROUGH THE END OF THE EFFECTIVE PERIOD AS A SURFACE TROUGH RESIDES OVER THE AREA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...FOLTZ LONG TERM...JRM AVIATION...FOLTZ
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1100 PM EDT TUE AUG 7 2012 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OF THE AREA TONIGHT. A WEAK FRONTAL BOUNDARY WILL APPROACH FROM THE NORTHWEST ON WEDNESDAY AND STALL OVER THE AREA THROUGH LATE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... UPDATE...TWEAKED TEMPERATURES TO MATCH THE LATEST TRENDS. RADAR SHOWING SOME SHOWERS MOVE NE ACROSS QUEBEC. RUC HAS SOME OF THESE SHOWERS SKIRTING NORTHERN AND NWRN AREAS OVERNIGHT INTO EARLY MORNING. LATEST FCST HAS THIS HANDLED WELL. PREVIOUS DISCUSSION... TONIGHT WILL REMAIN MOSTLY CLEAR IN SOUTHERN AND SOUTHEAST AREAS. SOME CLOUDS WILL GRADUALLY INCREASE ACROSS THE NORTHWEST AS A WEAK COLD FRONT SLOWLY APPROACHES FROM QUEBEC. SOME SHOWERS MAY AFFECT FAR NORTHWESTERN AREAS LATE TONIGHT OR WEDNESDAY MORNING. AS THE FRONT NEARS WEDNESDAY AFTERNOON SOME THUNDERSTORMS WILL BE POSSIBLE. THE BEST CHANCES FOR THUNDERSTORMS WEDNESDAY AFTERNOON WILL BE OVER FAR NORTHWESTERN AREAS NEAR THE FRONTAL BOUNDARY WHERE SOME CONVERGENCE WILL OFFER SUPPORT FOR THUNDERSTORM ACTIVITY. BOTH THE NAM AND GFS ARE FORECASTING CAPES NEAR 300 J/KG. CAPES AROUND 300 CAN SUPPORT SOME CONVECTION BUT ARE LIKELY TOO WEAK TO SUPPORT ANYTHING SEVERE. TEMPS TONIGHT WILL RANGE FROM THE MID 50S EAST WHERE SKIES WILL BE MOSTLY CLEAR TO NEAR 60 NORTHWEST WHERE SOME CLOUD COVER WILL LIMIT COOLING. TEMPS ON WEDNESDAY WILL BE IN THE LOW 80S IN MOST AREAS. && .SHORT TERM /WEDNESDAY NIGHT/... A WEAK AREA OF LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL MOVE ACROSS THE REGION WEDNESDAY NIGHT BRINGING SOME SHOWERS AND THUNDERSTORMS MAINLY TO THE NORTHERN HALF OF THE REGION. AS ABUNDANT LOW LEVEL MOISTURE IS DRAWN NORTH ON SOUTHERLY WINDS AHEAD OF THE FRONT THIS WILL RESULT IN FOG DEVELOPMENT OVER DOWNEAST AREAS. THE FRONT STALLS ACROSS THE REGION ON THURSDAY RESULTING IN CONSIDERABLE CLOUDINESS WITH ADDITIONAL SHOWERS AND THUNDERSTORMS. THE NAM DEPICTS CAPE VALUES EXCEEDING 1000 J/KG BY THE AFTERNOON WITH 0-6 KM SHEAR VALUES EXCEEDING 40 KNOTS. HOWEVER CLOUD COVER WILL ACT TO LIMIT THE POTENTIAL FOR SEVERE STORMS AS IT LIMITS HEATING. HAVE GONE WITH UPPER 70S NORTH AND LOW 80S SOUTH. ANY CONVECTION WILL WIND DOWN THURSDAY EVENING. HAVE MAINTAINED SHOWERS THROUGH THE NIGHT WITH THE FRONT STALLING DOWN EAST. LOWS WILL BE IN THE LOW TO MID 60S IN THE RATHER HUMID AIR MASS. MODELS BEGIN TO DIVERGE HEADING INTO FRIDAY. LOW PRESSURE LOOKS TO DEVELOP FRIDAY IN THE OHIO VALLEY WITH A SHIELD OF RAIN EXTENDING NORTH AND EAST FROM THIS SYSTEM ALONG THE FRONT. THE NAM AND THE ECMWF ARE FAIRLY AGGRESSIVE BRINGING STEADIER AND HEAVIER PRECIPITATION INTO THE REGION DURING THE DAY COMPARED TO THE GFS AND ESPECIALLY THE GEM GLOBAL. AT THIS POINT OPTED TO KEEP IN CHANCE POPS OVER MOST OF THE CWA WITH A SMALL AREA OF LIKELY POPS NUDGING INTO AREAS JUST WEST OF BANGOR BY LATE DAY. && .LONG TERM /THURSDAY THROUGH TUESDAY/... LOW PRESSURE WILL INTENSIFY ACROSS THE MID ATLANTIC REGION FRIDAY NIGHT WITH HIGH PRESSURE LOCATED NORTH OF THE REGION. THE LOW THEN SLOWLY LIFTS NORTH SATURDAY...WHILE HIGH PRESSURE MOVES NORTHEAST. UNCERTAINTY STILL EXISTS REGARDING HOW QUICKLY RAIN IS ABLE TO EXPAND ACROSS THE FORECAST AREA FRIDAY NIGHT THROUGH SATURDAY. HIGH PRESSURE TO THE NORTHEAST SHOULD HELP SUPPLY LOW LEVEL DRY AIR WHICH COULD SLOW THE EXPANSION OF RAIN ACROSS THE REGION. EXPECT THE BEST CHANCES OF RAIN WILL REMAIN ACROSS SOUTHWEST PORTIONS OF THE FORECAST AREA FRIDAY NIGHT THROUGH EARLY SATURDAY. THE RAIN SHOULD THEN EXPAND ACROSS THE REGION THROUGH THE REMAINDER OF SATURDAY. THE LOW WILL LIFT NORTH SATURDAY NIGHT THROUGH SUNDAY...DRAWING AN OCCLUDED FRONT ACROSS THE FORECAST AREA. RAIN IS EXPECTED ACROSS THE ENTIRE REGION SATURDAY NIGHT THROUGH EARLY SUNDAY IN ADVANCE OF THE OCCLUSION...WITH PRECIPITATION THEN TAPERING TO SHOWERS IN THE WAKE OF THE OCCLUSION LATER SUNDAY. THE LOW WILL LIFT NORTH OF THE REGION MONDAY...WITH A SLIGHT CHANCE OF SHOWERS LINGERING ACROSS NORTHERN AREAS. A COLD FRONT WILL APPROACH LATER TUESDAY BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO MOSTLY NORTHERN AREAS DURING THE AFTERNOON. TEMPERATURES SHOULD BE AT SLIGHTLY BELOW NORMAL LEVELS SATURDAY/SUNDAY...WITH NEAR NORMAL LEVEL TEMPERATURES EXPECTED MONDAY/TUESDAY. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: SOME PATCHY FOG MAY AFFECT DOWNEAST AREAS LATE TONIGHT. OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE AREA THROUGH WEDNESDAY. SHORT TERM: IFR LIKELY TO DEVELOP WEDNESDAY NIGHT SOUTH OF HUL AND MLT WITH STRATUS AND FOG. THIS WILL CONTINUE INTO EARLY THURSDAY MORNING. VFR FOR LATER THURSDAY MORNING INTO THE EVENING OUTSIDE OF THUNDERSTORMS. FOG AND STRATUS REAPPEARS THURSDAY NIGHT FOR ALL TERMINALS AND MAY BE VERY SLOW TO LIFT FRIDAY MORNING...ESPECIALLY DOWNEAST. LOW PRESSURE ARRIVES BY LATE DAY TO PROVIDE PREDOMINANT IFR FOR ALL SITES DUE TO LOW CLOUDS AND RAIN. CONDITIONS FRIDAY NIGHT THROUGH SATURDAY WILL BE DEPENDENT ON HOW QUICKLY RAIN IS ABLE TO EXPAND ACROSS THE REGION. HOWEVER...MVFR/IFR CONDITIONS ARE POSSIBLE FRIDAY NIGHT INTO SATURDAY WITH A MORE RAPID EXPANSION OF THE RAIN. MVFR/IFR CONDITIONS ARE THEN EXPECTED SATURDAY NIGHT INTO SUNDAY. && .MARINE... NEAR TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA TONIGHT AND WEDNESDAY. SHORT TERM: FOG IS EXPECTED WEDNESDAY NIGHT AND WILL REMAIN A FACTOR IN THE FORECAST THROUGH FRIDAY. CONDITIONS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS WEDNESDAY NIGHT THROUGH FRIDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
551 AM EDT MON AUG 6 2012 .SYNOPSIS... A FRONTAL BOUNDARY WILL SLIDE SLOWLY SOUTHEASTWARD EARLY TODAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FROM THE MIDWEST AND PROVIDE A DRY START TO THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... A QUICK EARLY MORNING UPDATE HAS BEEN ISSUED TO SPEED UP CLEARING THIS MORNING AS DRIER DEW POINTS ADVECT INTO WESTERN PA FROM OHIO. IN ADDITION, POP GRIDS HAVE BEEN REDUCED TO SCHC ACROSS THE WV/MD RIDGES FOR THIS MORNING INTO THE EARLY AFTERNOON. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A WEAK VORT MAX ADVECTING SLOWLY SOUTHEASTWARD FROM EASTERN OHIO INTO NORTH-CENTRAL WV. AT THE SURFACE, A FRONTAL BOUNDARY, MOST EVIDENT BY THE DEW POINT GRADIENT, EXTENDS FROM ZANESVILLE TO BUTLER TO DU BOIS. WITH TDS STILL IN THE UPPER 60S AND ABUNDANT LOW-LEVEL MOISTURE FROM RECENT RAINFALL, PATCHY FOG HAS DEVELOPED SOUTH AND EAST OF THE PITTSBURGH METRO. THE BACK EDGE OF THE CLOUD DECK IS REACHING WESTERN PA WITH CLEARING IN OHIO. TODAY AND TONIGHT...THE FRONTAL BOUNDARY WILL SLOWLY SEEP SOUTHEASTWARD AS A DEEP LAYER OF DRY AIR ADVECTS INTO THE AREA WITH THE HIGH SHIFTING EASTWARD INTO THE OHIO VALLEY. THIS WILL ALLOW FOR ANY LINGERING CONVECTION TO PUSH SOUTHEAST OF THE WV/MD RIDGES. SOME CLEARING WILL OCCUR FROM THE WEST INITIALLY, FOLLOWED BY SCATTERED CUMULUS DEVELOPING DURING THE LATE MORNING. THE MOST CLOUD COVERAGE IS ANTICIPATED EARLY FOR AREAS SOUTH OF THE BOUNDARY. A GENERAL CLEARING TREND IS EXPECTED LATER THIS AFTERNOON INTO THE EVENING. HIGHS TODAY SIDE WITH THE COOLER MAV EVERYWHERE EXCEPT ACROSS NORTH-CENTRAL WV WHERE THE BOUNDARY WILL BE SLOWER TO CLEAR. WITH CLEAR SKIES AND NEAR CALM WINDS OVERNIGHT, THIS WILL ALLOW FOR RADIATIONAL COOLING TONIGHT. LOWS ARE CLOSER TO THE COOLER MAV GUIDANCE, RANGING FROM NEAR 50 ACROSS THE I-80 CORRIDOR TO THE UPPER 50S ACROSS NORTH-CENTRAL WV. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... THERE IS NAM/GFS AGREEMENT THAT THE DEEP LAYER OF DRY AIR WILL REMAIN ACROSS THE AREA AS THE SURFACE HIGH SHIFTS EAST OF THE AREA ON TUESDAY. WITH THIS IN MIND, ABUNDANT SUNSHINE IS ANTICIPATED. 850MB TEMPS WARMING TO AROUND 16C ON TUESDAY ALONG WITH SUNSHINE WILL ALLOW FOR HIGHS TO BE AROUND 5 DEGREES ABOVE SEASONAL NORMALS. FORECAST UNCERTAINTY BEGINS WEDNESDAY AS THE NEXT FRONTAL BOUNDARY APPROACHES FROM THE NORTHWEST AND SOUTHWESTERLY WINDS INCREASE LOW-LEVEL MOISTURE ACROSS THE AREA LATE IN THE DAY. WITH LITTLE FORCING, INSTABILITY, AND SHEAR, FORECAST IS CLOSEST TO THE COOLER GFS AND CONSISTS OF SCHC POPS. TEMPS WILL CONTINUE TO BE AROUND 5 DEGREES ABOVE NORMAL FOR HIGHS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO MAJOR CHANGES TO EXTENDED FORECAST CONSIDERING FOCUS WAS ON POSSIBLE SEVERE WEATHER FOR TODAY. MODELS STILL NOT SHOWING MUCH AGREEMENT ON FRONTAL PASSAGE FOR END OF THE WORK WEEK. 12Z GFS BRINGS FRONT THROUGH ON THURSDAY...00Z ECMWF BRINGS FRONT THROUGH ON THURSDAY/FRIDAY...AND 00Z GEFS BRINGS FRONT THROUGH ON FRIDAY. AT THIS POINT...HAVE STUCK CLOSE TO PREVIOUS FORECAST...WHICH BRINGS FRONT THROUGH ON FRIDAY. TEMPERATURES WILL TURN COOLER FOR THE WEEKEND...WITH HIGHS DROPPING INTO THE 70S. AN ISOLATED SHOWER CANNOT BE RULED OUT OVER THE WEEKEND WITH RELATIVELY COOLER 850MB AIR (10-12C) PASSING OVER A WARM LAKE ERIE (23-25C). && .AVIATION /10Z MONDAY THROUGH FRIDAY/... STRATUS...AND FOG WHEREVER A BREAK IN THE STRATUS OCCURS...WILL PLAGUE MOST OF THE TERMINALS THROUGH THE NIGHT. LOW LEVEL DRYING HAS BEEN SLOW TO WORK INTO THE AREA BEHIND THE FRONT AS OVERNIGHT INVERSIONS AND A LACK OF MIXING HAS REALLY STARTED TO CONTROL THE LOW LEVELS. AS SUCH...DEWPOINTS REMAIN IN THE 66-72F DEGREE RANGE AT ALL TERMINALS...WHILE JUST A BIT TO THE NW FROM KDAY TO KCAK...THEY ARE RUNNING IN THE UPPER 50S. WITH A WEAK ISALLOBARIC FLOW LIKELY OVERNIGHT...ONLY KFKL AND KZZV HAVE A DECENT SHOT AT BREAKING OUT...OTHERWISE ALL SITES SHOULD REMAIN IN THE IFR OR LOWER FOG/STRATUS THROUGH MORNING. AFTER SUNRISE...LOW LEVEL DRYING WILL TAKE PLACE RAPIDLY FROM N TO S...WITH JUST A FEW CUMULUS LIKELY BY THE AFTERNOON. FRIES OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... VFR CONDITIONS WILL MOSTLY PREVAIL THROUGH WEDNESDAY AS HIGH PRESSURE CROSSES THE OHIO VALLEY. LOW PRESSURE MOVING INTO THE GREAT LAKES WILL RETURN THE CHANCE OF THUNDERSTORMS AND RESTRICTIONS BY THE END OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
417 AM EDT MON AUG 6 2012 .SYNOPSIS... A FRONTAL BOUNDARY WILL SLIDE SLOWLY SOUTHWARD EARLY TODAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FROM THE MIDWEST AND PROVIDE A DRY START TO THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A WEAK VORT MAX ADVECTING SLOWLY SOUTHEASTWARD FROM EASTERN OHIO INTO NORTH-CENTRAL WV. AT THE SURFACE, A FRONTAL BOUNDARY, MOST EVIDENT BY THE DEW POINT GRADIENT, EXTENDS FROM ALONG A LINE JUST NORTH OF NEW PHILADELPHIA TO NEW CASTLE TO DU BOIS. SHOWERS THAT HAVE BEEN CONFINED TO LOCATIONS SOUTH OF THE BOUNDARY ARE QUICKLY COMING TO AN END THIS MORNING. WITH TDS STILL IN THE LOWER 70S AND ABUNDANT LOW-LEVEL MOISTURE FROM RECENT RAINFALL, PATCHY FOG HAS DEVELOPED ACROSS THE AREA. IN ADDITION, FURTHER UPSTREAM SKIES ARE CLEAR, AS A SURFACE HIGH IS CENTERED ACROSS THE MIDWEST. TODAY AND TONIGHT...THE FRONTAL BOUNDARY WILL SLOWLY SEEP SOUTHWARD AS A DEEP LAYER OF DRY AIR ADVECTS INTO THE AREA WITH THE HIGH SHIFTING EASTWARD INTO THE OHIO VALLEY. THIS WILL ALLOW FOR ANY LINGERING SHOWERS AND THUNDERSTORMS TO PUSH SOUTHEAST OF THE WV/MD RIDGES. SOME CLEARING WILL OCCUR FROM THE WEST INITIALLY, FOLLOWED BY SCATTERED CUMULUS DEVELOPING DURING THE LATE MORNING. THE MOST CLOUD COVERAGE IS ANTICIPATED EARLY FOR AREAS SOUTH OF THE BOUNDARY. A GENERALLY CLEARING TREND IS EXPECTED LATER THIS AFTERNOON INTO THE EVENING. HIGHS TODAY SIDE WITH THE COOLER MAV EVERYWHERE EXCEPT ACROSS NORTH-CENTRAL WV, WHERE THE BOUNDARY WILL BE SLOW TO CLEAR. THE SKIES WILL CLEAR LATER TODAY AND TONIGHT AS THE HIGH BECOMES CENTERED OVER THE UPPER OHIO VALLEY. WITH CLEAR SKIES AND NEAR CALM WINDS, THIS WILL ALLOW FOR RADIATIONAL COOLING TONIGHT. LOWS ARE CLOSER TO THE COOLER MAV GUIDANCE, RANGING FROM THE LOWER 50S ACROSS THE I-80 CORRIDOR TO THE UPPER 50S ACROSS NORTH-CENTRAL WV. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... THERE IS NAM/GFS AGREEMENT THAT THE DEEP LAYER OF DRY AIR WILL REMAIN ACROSS THE AREA AS THE SURFACE HIGH SHIFTS EAST OF THE AREA ON TUESDAY. WITH THIS IN MIND, ABUNDANT SUNSHINE IS ANTICIPATED. 850MB TEMPS WARMING TO AROUND 16C ON TUESDAY ALONG WITH SUNSHINE WILL ALLOW FOR HIGHS TO BE AROUND 5 DEGREES ABOVE SEASONAL NORMALS. FORECAST UNCERTAINTY BEGINS WEDNESDAY AS THE NEXT FRONTAL BOUNDARY APPROACHES FROM THE NORTHWEST AND SOUTHWESTERLY WINDS INCREASE LOW-LEVEL MOISTURE ACROSS THE AREA LATE IN THE DAY. WITH LITTLE FORCING, INSTABILITY, AND SHEAR, FORECAST IS CLOSEST TO THE COOLER GFS AND CONSISTS OF SCHC POPS. TEMPS WILL CONTINUE TO BE AROUND 5 DEGREES ABOVE NORMAL FOR HIGHS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO MAJOR CHANGES TO EXTENDED FORECAST CONSIDERING FOCUS WAS ON POSSIBLE SEVERE WEATHER FOR TODAY. MODELS STILL NOT SHOWING MUCH AGREEMENT ON FRONTAL PASSAGE FOR END OF THE WORK WEEK. 12Z GFS BRINGS FRONT THROUGH ON THURSDAY...00Z ECMWF BRINGS FRONT THROUGH ON THURSDAY/FRIDAY...AND 00Z GEFS BRINGS FRONT THROUGH ON FRIDAY. AT THIS POINT...HAVE STUCK CLOSE TO PREVIOUS FORECAST...WHICH BRINGS FRONT THROUGH ON FRIDAY. TEMPERATURES WILL TURN COOLER FOR THE WEEKEND...WITH HIGHS DROPPING INTO THE 70S. AN ISOLATED SHOWER CANNOT BE RULED OUT OVER THE WEEKEND WITH RELATIVELY COOLER 850MB AIR (10-12C) PASSING OVER A WARM LAKE ERIE (23-25C). && .AVIATION /08Z MONDAY THROUGH FRIDAY/... STRATUS...AND FOG WHEREVER A BREAK IN THE STRATUS OCCURS...WILL PLAGUE MOST OF THE TERMINALS THROUGH THE NIGHT. LOW LEVEL DRYING HAS BEEN SLOW TO WORK INTO THE AREA BEHIND THE FRONT AS OVERNIGHT INVERSIONS AND A LACK OF MIXING HAS REALLY STARTED TO CONTROL THE LOW LEVELS. AS SUCH...DEWPOINTS REMAIN IN THE 66-72F DEGREE RANGE AT ALL TERMINALS...WHILE JUST A BIT TO THE NW FROM KDAY TO KCAK...THEY ARE RUNNING IN THE UPPER 50S. WITH A WEAK ISALLOBARIC FLOW LIKELY OVERNIGHT...ONLY KFKL AND KZZV HAVE A DECENT SHOT AT BREAKING OUT...OTHERWISE ALL SITES SHOULD REMAIN IN THE IFR OR LOWER FOG/STRATUS THROUGH MORNING. AFTER SUNRISE...LOW LEVEL DRYING WILL TAKE PLACE RAPIDLY FROM N TO S...WITH JUST A FEW CUMULUS LIKELY BY THE AFTERNOON. FRIES OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... VFR CONDITIONS WILL MOSTLY PREVAIL THROUGH WEDNESDAY AS HIGH PRESSURE CROSSES THE OHIO VALLEY. LOW PRESSURE MOVING INTO THE GREAT LAKES WILL RETURN THE CHANCE OF THUNDERSTORMS AND RESTRICTIONS BY THE END OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
221 AM EDT MON AUG 6 2012 .SYNOPSIS... A FRONTAL BOUNDARY WILL SLIDE SLOWLY SOUTHWARD EARLY TODAY, WITH SHOWERS COMING TO AN END THIS MORNING. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FROM THE MIDWEST AND PROVIDE A DRY START TO THE WEEK. && .NEAR TERM /THROUGH TODAY/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A WEAK VORT MAX ADVECTING SLOWLY SOUTHEASTWARD FROM SW PA INTO NORTH-CENTRAL WV AND WESTERN MD. AT THE SURFACE, A FRONTAL BOUNDARY, MOST EVIDENT BY THE DEW POINT GRADIENT, EXTENDS FROM ALONG A LINE JUST NORTH OF NEW PHILADELPHIA TO NEW CASTLE TO DUBOIS. REMAINING SHOWERS SOUTH OF THE BOUNDARY ARE CONFINED MOSTLY TO NORTH-CENTRAL WV. WITH TDS STILL IN THE LOWER 70S AND ABUNDANT LOW- LEVEL MOISTURE FROM RECENT RAINFALL, PATCHY FOG HAS BEGUN TO DEVELOP ACROSS THE AREA. IN ADDITION, FURTHER UPSTREAM SKIES ARE CLEAR, AS A SURFACE HIGH IS CENTERED ACROSS THE MIDWEST. TODAY AND TONIGHT...THE FRONTAL BOUNDARY WILL SLOWLY SEEP SOUTHWARD AS A DEEP LAYER OF DRY AIR ADVECTS INTO THE AREA WITH THE HIGH SHIFTING EASTWARD INTO THE OHIO VALLEY. THIS ALLOW FOR SHOWERS AND THUNDERSTORMS ACROSS TO PUSH SOUTHEAST OF THE WV/MD RIDGES. CUMULUS WILL DEVELOP TODAY, WITH THE MOST CLOUD COVERAGE EARLY FOR AREAS SOUTH OF THE BOUNDARY. HIGHS TODAY SIDE WITH THE COOLER MAV EVERYWHERE EXCEPT ACROSS NORTH-CENTRAL WV, WHERE THE BOUNDARY WILL BE SLOW TO CLEAR. THE SKIES WILL CLEAR LATER TODAY AND TONIGHT AS THE HIGH BECOMES CENTERED OVER THE UPPER OHIO VALLEY. WITH CLEAR SKIES AND NEAR CALM WINDS, THIS WILL ALLOW FOR RADIATIONAL COOLING TONIGHT. LOWS ARE CLOSER TO THE COOLER MAV GUIDANCE, RANGING FROM THE LOWER 50S ACROSS THE I-80 CORRIDOR TO THE UPPER 50S ACROSS NORTH-CENTRAL WV. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL REMAIN THE MAIN STORY THROUGH MOST OF WEDNESDAY. WITH STRONG SUBSIDENCE AND RADIATIVE COOLING...TEMPERATURES OVERNIGHT MONDAY AND TUESDAY COULD BE BELOW NORMAL AND INTO THE 50`S. THIS IS CLOSEST TO MAV GUIDANCE THROUGH THE PERIOD. MODELS ARE IN DISAGREEMENT ON THE APPROACH OF THE NEXT SYSTEM WITH THE NAM BRINGING A FRONTAL BOUNDARY/SHORTWAVE ACROSS THE REGION LATE WEDNESDAY. THIS IS QUICKER THAN THE GFS. AT THIS POINT...WILL JUST HEDGE WITH SLIGHT CHANCE POPS WITH THE TIMING INCONSISTENCIES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... NO MAJOR CHANGES TO EXTENDED FORECAST CONSIDERING FOCUS WAS ON POSSIBLE SEVERE WEATHER FOR TODAY. MODELS STILL NOT SHOWING MUCH AGREEMENT ON FRONTAL PASSAGE FOR END OF THE WORK WEEK. 12Z GFS BRINGS FRONT THROUGH ON THURSDAY...00Z ECMWF BRINGS FRONT THROUGH ON THURSDAY/FRIDAY...AND 00Z GEFS BRINGS FRONT THROUGH ON FRIDAY. AT THIS POINT...HAVE STUCK CLOSE TO PREVIOUS FORECAST...WHICH BRINGS FRONT THROUGH ON FRIDAY. TEMPERATURES WILL TURN COOLER FOR THE WEEKEND...WITH HIGHS DROPPING INTO THE 70S. AN ISOLATED SHOWER CANNOT BE RULED OUT OVER THE WEEKEND WITH RELATIVELY COOLER 850MB AIR (10-12C) PASSING OVER A WARM LAKE ERIE (23-25C). && .AVIATION /06Z MONDAY THROUGH FRIDAY/... STRATUS...AND FOG WHEREVER A BREAK IN THE STRATUS OCCURS...WILL PLAGUE MOST OF THE TERMINALS THROUGH THE NIGHT. LOW LEVEL DRYING HAS BEEN SLOW TO WORK INTO THE AREA BEHIND THE FRONT AS OVERNIGHT INVERSIONS AND A LACK OF MIXING HAS REALLY STARTED TO CONTROL THE LOW LEVELS. AS SUCH...DEWPOINTS REMAIN IN THE 66-72F DEGREE RANGE AT ALL TERMINALS...WHILE JUST A BIT TO THE NW FROM KDAY TO KCAK...THEY ARE RUNNING IN THE UPPER 50S. WITH A WEAK ISALLOBARIC FLOW LIKELY OVERNIGHT...ONLY KFKL AND KZZV HAVE A DECENT SHOT AT BREAKING OUT...OTHERWISE ALL SITES SHOULD REMAIN IN THE IFR OR LOWER FOG/STRATUS THROUGH MORNING. AFTER SUNRISE...LOW LEVEL DRYING WILL TAKE PLACE RAPIDLY FROM N TO S...WITH JUST A FEW CUMULUS LIKELY BY THE AFTERNOON. FRIES OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... VFR CONDITIONS WILL MOSTLY PREVAIL THROUGH WEDNESDAY AS HIGH PRESSURE CROSSES THE OHIO VALLEY. LOW PRESSURE MOVING INTO THE GREAT LAKES WILL RETURN THE CHANCE OF THUNDERSTORMS AND RESTRICTIONS BY THE END OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
414 PM CDT MON AUG 6 2012 .DISCUSSION... OVERVIEW...ABOVE NORMAL TEMPS EXPECTED TOMORROW BEFORE SHOWERS AND STORMS ON WEDNESDAY KICK START A COOLING TREND THAT WILL LAST THROUGH THE WEEKEND. RAIN CHANCES ON THURSDAY AND FRIDAY ARE BASED ON TWO INDEPENDENT FEATURES. INCREASED POPS DURING THIS TIME FRAME. CERTAINLY A NON ZERO CHANCE OF PRECIP TONIGHT IN WESTERN WI AND IN FAR SOUTHERN MN. A COUPLE RUNS OF THE HRRR AND THE RAP BOTH HIGHLIGHT THESE AREAS WITH SHOWERS LATE THIS EVENING. SEEING THE EFFECTS OF THE COLD FRONT STRETCHED OUT ACROSS NORTHERN MM. GETTING NEAR SURFACE CONVERGENCE SHOWING UP IN THE MESO ANALYSIS BUT ALSO PRETTY OBVIOUS JUST BASED ON THE LOW LEVEL FLOW. NICE BAND OF CUMULUS AND EVENED EMBEDDED SHOWERS VISIBLE THIS AFTERNOON. SECONDLY...SUBTLE SHORTWAVE ENERGY IN THE EASTERN DAKOTAS ALSO DROPPING SOUTH THIS AFTERNOON. NOT MUCH BEING REFLECTED IN THE SHORT TERM HEIGHT/VORTICITY FIELDS...BUT DEFINITELY SOMETHING APPARENT ON THE WATER VAPOR. IN GENERALLY...TRIMMED THE POPS BACK TONIGHT. POP VALUES WERE ALREADY LOW...IN THE 20-30%...BY LIMITED THE AREAL EXTEND OF THE POPS COMPARED TO THE PREVIOUS FORECAST. THINK A VAST MAJORITY OF THE FORECAST AREA REMAINS DRY EVEN WITH THE WEAK FRONTAL PASSAGE. WONDERING IF THE HIGH DEWPOINT BIAS OFF THE RAP IS PLAYING INTO THE EXTRA PRECIP TONIGHT. REALLY CAN NOT SEE HOW MUCH DIFFERENT TOMORROW WILL BE COMPARED TO TODAY IN TERMS OF TEMPERATURES. IT MIGHT BE A DEGREE OR TWO COOLER THAN TODAY...BUT 70-80% OF THE GUIDANCE HAS FORECAST 2M TEMPS AND 850MB TEMPS VERY SIMILAR TO WHAT WAS SEEN TODAY. STILL LOOKS GOOD FOR AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS ON WEDNESDAY WITH SHORTWAVE ROTATING AROUND THE RIDGE OVER THE NEXT 36-48HRS. SHEAR IS MARGINAL WITH RELATIVELY WEAK MID LEVEL FLOW...BUT FORCING AND INSTABILITY SHOULD NOT BE A PROBLEM...SO LIKELY POPS ARE NOT A STRETCH AT THIS POINT. WE BLEED THE POPS INTO THURSDAY DUE TO THE UPPER LOW DROPPING SOUTH OUT OF THE INTERIOR OF CANADA...NOW IN NORTH CENTRAL CANADA BETWEEN 70-75 NORTH. THIS SYSTEM HAS PROBABLY TRENDED A LITTLE BIT SLOWER AND STRONGER WITH TIME OVER THE LAST COUPLE DAYS. THERE IS NOT MUCH RECOVERY IN TERMS OF INSTABILITY...BUT COOL TEMPS ALOFT SUGGESTS SHOWERY ACTIVITY WITH EMBEDDED THUNDER. COOLED TEMPS ON THURSDAY...MIGHT BE HARD TO GET MUCH ABOVE 75 IN SOME LOCATIONS IN CENTRAL MN AND WI WITH CLOUD COVER AND SHOWERS. && .AVIATION.../18Z TAF ISSUANCE/ ONLY ITEM OF INTEREST THIS TAF PERIOD IS THE PASSAGE OF A COLD FRONT THIS EVENING...THAT SHOULD COME THROUGH WITHOUT MUCH MORE THAN A WIND SHIFT. MAIN SHORTWAVE DRIVING THIS FRONT IS GOING ACROSS LAKE SUPERIOR NOW...WHICH MEANS THERE IS LITTLE UPPER SUPPORT FOR PRECIP THIS FAR SOUTH. THIS COMBINED WITH THE STILL DRY ATMO AFTER FRIDAY NIGHTS FROPA AND WEAK CONVERGENCE ALONG THE FRONT SHOULD MAKE IT TOUGH TO GET MUCH ACTIVITY GOING. CAN NOT RULE IT OUT...BUT CONFIDENCE/COVERAGE IN PRECIP NOT HIGH ENOUGH TO INCLUDE A VC MENTION. FOR THE WIND SHIFT OVER TO THE NORTH...FOLLOWED LAV TIMING...WHICH HAS GOOD AGREEMENT WITH THE HRRR/RAP/SREF. KMSP...FRONT WILL SLIP THROUGH THE MSP AREA BETWEEN 6Z AND 8Z...WITH WINDS VEERING OVER TOWARD THE NORTH BEHIND IT. BEST SHOT FOR SEEING STORMS WOULD BE BETWEEN 5Z AND 9Z...BUT NOT EXPECTING MUCH COVERAGE IF ANYTHING DOES DEVELOPED...SO REMOVED THE VCSH. OUTSIDE OF THAT...WILL BE ANOTHER QUIET PERIOD. /OUTLOOK/ .WEDNESDAY...VFR WITH MVFR/TSRA POSSIBLE. WINDS SE AT 5-10 KTS. .THURSDAY...MVFR CLOUDS AND SHRA DURING THE DAY...BECOMING VFR OVERNIGHT. WINDS N AT 10G15 KTS. .FRIDAY...VFR. WINDS E 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ CLF/MPG
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1200 AM MDT MON AUG 6 2012 .AVIATION... 06Z TAF CYCLE SOME LINGERING SHOWERS AND THUNDERSTORMS MAINLY NEAR AND N OF INTERSTATE 40 FOR A FEW HOURS PAST MIDNIGHT BEFORE MOST OF THEM DIMINISH. MOST OF THE ACTIVITY WILL NOT BE STRONG ENOUGH TO CREATE MAJOR AVIATION HAZARDS...THOUGH SOME BRIEF MVFR CONDITIONS POSSIBLE WITH THE STRONGEST ACTIVITY IN MAINLY CENTRAL AND PERHAPS NE NM. ALSO A FEW POCKETS OF MVFR OR VERY LOCALLY IFR CIGS AND FOG IN WETTER NORTHERN MT VALLEYS AND IMMEDIATE E SLOPES OF SANGRE DE CRISTOS...ESPECIALLY AFTER 09Z UNTIL MID MORN MON. WHILE SOME SHRA AND TSRA LIKELY TO DEVELOP IN ISOLATED TO SCT FASHION MAINLY ACROSS N AND W CENTRAL MT REGIONS AFTER 19Z...COVERAGE AND INTENSITY SHOULD OVERALL BE A LITTLE LESS THAN TODAY. VERY LOCALIZED AND BRIEF MVFR CIGS STILL POSS WITH STRONGEST STORMS...BUT LESS THAN ON SUN. 43 && .PREV DISCUSSION...1024 PM MDT SUN AUG 5 2012... FIRST ORDER OF BUSINESS WAS TO EXPIRE THE FLASH FLOOD WATCH AT 10 PM. ABX RADAR INDICATED HANDS DOWN OUR BEST STORM CORE PRECIP TOTALS ACROSS THE WEST TODAY. A FEW AREAS MAY HAVE PICKED UP 4 TO 6 INCHES OF RAIN. ONE SUCH AREA WAS THOREAU WHERE SIGNIFICANT FLASH FLOODING HAS BEEN REPORTED TODAY. NOW THE FOCUS IS WHERE ADJUST HIGHEST POPS. CURRENTLY THE RADAR AND SATELLITE TRENDS FOCUS THE BEST COVERAGE OVER THE NORTHERN MTS AND STILL SOMEWHAT ALONG THE CONT DVD. THE 01Z HRRR AND 03Z RUC HANDLE THE CURRENT PRECIP WELL SO HAVE GONE IN THIS DIRECTION ONCE AGAIN TONIGHT. THEREFORE EXPECTING CURRENT NMRS COVERAGE ACROSS THE NORTH TO MOVE SLOWLY ESE INTO THE JEMEZ AND SOUTHERN SANGRES AND THE NE HIGHLANDS. PLACED SCATTERED COVERAGE THERE WITH ISOLD AT BEST FOR THE REMAINDER OF THE AREA. GUYER .PREV DISCUSSION...610 PM MDT SUN AUG 5 2012... .AVIATION... 00Z TAF CYCLE ANOTHER FAIRLY ACTIVE CONVECTIVE DAY WAS REALIZED TODAY...BUT MAINLY JUST ACROSS THE NW THIRD OR SO OF THE STATE. THROUGH THIS EVE EXPECT SCT TO LOCALLY NUMEROUS SHRA AND TSRA AGAIN MOSTLY WEST AND NORTH NM. STRONGEST STORMS WILL LIKELY ALSO REMAIN MAINLY N AND W WITH LOCALIZED AND RELATIVELY SHORT LIVED MVFR CIGS AS WELL AS ISOLATED INSTANCES OF SMALL HAIL ASSOCIATED WITH STRONGER TSRA. TSRA MENTIONED ONLY IN SAF...LVS AND FMN TO ACCOUNT FOR BEST CHANCE LOCALES FOR TSRA. OTHERWISE IN AREAS ALREADY WORKED OVER IN WEST OR OTHERWISE TOO UNLIKELY TO PICK UP A TSRA IN CENTRAL AND E NM EITHER VCSH MENTIONED OR NOTHING AT ALL.. MOST IF NOT ALL TSRA SHOULD DISSIPATE BY OR WITHIN A COUPLE HOURS OF MIDNIGHT. WHILE SOME SHRA AND TSRA LIKELY TO DEVELOP MON MAINLY AFTER 19Z...COVERAGE AND INTENSITY SHOULD OVERALL BE A LITTLE LESS THAN TODAY. 43 .PREV DISCUSSION...315 PM MDT SUN AUG 5 2012... AS EXPECTED...SOMEWHAT OF A SLOW START TO THE SHOWER AND THUNDERSTORM DEVELOPMENT THIS AFTERNOON. PRECIPITABLE WATER VALUES IN THE FLASH FLOOD WATCH AREA REMAIN ABOUT 120-150 PERCENT OF NORMAL SO NO CHANGES TO THE ONGOING WATCH. LOW LEVEL GULF MOISTURE COMBINING WITH MID LEVEL MONSOON MOISTURE PLUME TO GET PWAT VALUES UP THIS HIGH. STORMS FIRING OVER THE WEST-CENTRAL MTNS ARE MOVING NORTH AROUND 15 KTS BUT TRAINING OF SHOWERS AND STORMS OVER THE SAME AREA/DRAINAGE REMAINS THE MAIN CONCERN. DOPPLER RADAR ESTIMATING OVER 2 INCHES OF RAIN HAVE FALLEN FROM ONE CELL OR CELLS TRAINING OVER THOREAU IN THE PAST HOUR AND A HALF. ELSEWHERE...STORMS ARE DEVELOPING OVER THE NORTHERN MOUNTAINS AND SUSPECT THAT STORMS WILL BEGIN FIRING OVER OTHER MOUNTAIN LOCATIONS SHORTLY...AS MORE SURFACE HEATING ALLOWS UPDRAFTS TO PUNCH THROUGH THE SUBSIDENCE INVERSION AROUND 14K FEET AGL. MODELS ARE IN VERY GOOD TO EXCELLENT AGREEMENT FOR MONDAY...SLIDING THE CENTER OF THE UPPER LEVEL HIGH OVER NORTHWEST NM. STEERING LEVEL FLOW GRADUALLY BECOMES NORTH/NORTHWESTERLY OVER THE NORTH AND NORTHEAST TO EASTERLY OVER THE SOUTHWEST MOUNTAINS. RESIDUAL MOISTURE WILL COMBINE WITH THE ELEVATED HEAT SOURCES/MOUNTAINS TO GET SCATTERED SHOWERS AND THUNDERSTORMS GOING MONDAY AFTERNOON. HIGH RESOLUTION MODELS INDICATING THAT STORMS MOVING SOUTH FROM THE JEMEZ MOUNTAINS COULD BRING A ROUND OF THUNDERSTORMS TO BERNALILLO AND THE ALBUQUERQUE METRO AREA EARLY MONDAY EVENING. AND WITH STORM MOTION BECOMING NORTHWESTERLY MONDAY LATE AFTERNOON AND EVENING...SHOWERS AND STORMS WILL MOVE OFF THE SANGRE DE CRISTOS OUT ONTO THE NORTHEAST HIGHLANDS AND PLAINS. TUESDAY LOOKS VERY SIMILAR TO MONDAY WITH ONE EXCEPTION. AS THE UPPER HIGH CENTER SHIFTS FAR ENOUGH WESTWARD...NELY FLOW AT ALL LEVELS DEVELOPS AND BRINGS GULF MOISTURE TO THE NERN PLAINS AND CENTRAL HIGHLANDS TUESDAY AFTERNOON AND EVENING. THE MOIST NELY FLOW COMBINES WITH A WEAK WAVE TRANSLATING AROUND THE UPPER HIGH TO BRING HIGHER STORM CHANCES FROM THE CENTRAL MOUNTAINS EWD TUESDAY AFTERNOON AND EVENING. SIMILAR UPPER LEVEL AND SURFACE PATTERN CONTINUES INTO WEDNESDAY. DRIER MID AND UPPER LEVEL AIR BEGINS TO FILTER INTO CENTRAL AND SRN NM THURSDAY...WITH THE BEST THUNDERSTORM CHANCES OVER THE NRN MOUNTAINS. FRIDAY LOOKS...AT THIS POINT...LIKE THE DOWN DAY FOR THUNDERSTORMS THIS WEEK...OUTSIDE OF THE NRN AND WRN MOUNTAINS BUT WITH A NELY STEERING LEVEL FLOW IN PLACE...CANNOT RULE OUT SLIGHT CHANCES/ISOLATED STORMS FOR THE CENTRAL VALLEYS AS STORMS MOVE SOUTHWESTWARD. EXCELLENT AGREEMENT IN THE MEDIUM RANGE OPERATIONAL MODELS EXISTS FOR NEXT WEEKEND. UPPER HIGH REMAINS FAR ENOUGH NORTHWEST OF THE STATE FOR OCCASIONAL SHORT-WAVES/DISTURBANCES TO ROTATE AROUND THE HIGH CENTER AND INITIATE A NORTHEAST TO ELY SURFACE FLOW OVER THE REGION...RECHARGING SFC MOISTURE. THIS NW FLOW ALOFT IS QUITE THE FAVORABLE PATTERN FOR THE NORTHEAST AND EAST CENTRAL PLAINS. LONG RANGE FORECASTS GET QUITE INTERESTING. LATEST ECMWF FORECASTS A MAJOR BLOCKING PATTERN (OMEGA BLOCK) OVER THE GULF OF ALASKA...FORCING A LARGE AND UNSEASONABLY DEEP CLOSED UPPER LEVEL LOW OVER THE PACNW. THIS PATTERN WOULD FORCE THE UPPER HIGH BACK OVER THE SRN PLAINS STATES AND POSSIBLY OPEN THE DOOR FOR A DEEP SOUTHERLY FETCH OF SUBTROPICAL/TROPICAL MOISTURE INTO THE STATE. WE SHALL SEE. 33 .FIRE WEATHER... SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE QUITE NUMEROUS GOING INTO THE EVENING...ESPECIALLY ACROSS WESTERN AND NORTHERN PARTS OF NEW MEXICO. THIS BOOST IN STORM COVERAGE AND THE RELATIVELY LARGE FOOTPRINT OF WETTING RAINS RECEIVED YESTERDAY SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS THROUGH THE NEAR TERM. BACK DOOR FRONT ADVANCED TOWARD ARIZONA...AND SHOULD CONTINUE TO PROVIDE SOME UPSLOPE TO AID IN THUNDERSTORM DEVELOPMENT ALONG AND NEAR THE CONTINENTAL DIVIDE. TEMPERATURES HAVE ALSO FALLEN BACK TO MORE REASONABLE VALUES AND CLOSER TO SEASONAL AVERAGES...ESPECIALLY IN THE EASTERN PLAINS. THIS ALONG WITH INCREASED CLOUD COVER AND ANTECEDENT RAIN CONDITIONS HAS KEPT RELATIVE HUMIDITY AT OR ABOVE 30 PERCENT IN THE FORECAST AREA...AND ANY GAP/CANYON WINDS HAVE DIMINISHED. GOOD TO EXCELLENT RH RECOVERY CAN BE EXPECTED TONIGHT AND INTO EARLY MONDAY MORNING. AS HIGH PRESSURE ALOFT REGAINS SOME SYMMETRY OVER THE FOUR CORNERS...IT WILL STEER FEWER STORMS INTO THE NORTHERN AND WESTERN MOUNTAINS OF NEW MEXICO ON MONDAY. ONCE THE HIGH NUDGES NORTHWESTWARD INTO TUESDAY...ANOTHER BACK DOOR FRONT WILL SLIDE INTO THE NORTHEASTERN PLAINS OF NEW MEXICO. AT THIS POINT...THE DIRECTIONAL SHIFT IN THE WINDS APPEARS TO BE A PRIMARY IMPACT AS NO MAJOR INCREASE IN DEWPOINTS IS ANTICIPATED. ANY UPTICK IN STORM COVERAGE IN THE NORTHEAST ON TUESDAY WOULD BE FAIRLY SUBTLE. FROM MID WEEK AND THROUGH THE EXTENDED FORECAST PERIOD VERY LITTLE MOVEMENT OF THE UPPER LEVEL HIGH IS FORESEEN. THIS WILL LIKELY DRIVE STORMS MOSTLY TO THE NORTHERN AND WESTERN MOUNTAINS OF NEW MEXICO WITH LESS THAN AVERAGE COVERAGE. && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1024 PM MDT SUN AUG 5 2012 .UPDATE... FIRST ORDER OF BUSINESS WAS TO EXPIRE THE FLASH FLOOD WATCH AT 10 PM. ABX RADAR INDICATED HANDS DOWN OUR BEST STORM CORE PRECIP TOTALS ACROSS THE WEST TODAY. A FEW AREAS MAY HAVE PICKED UP 4 TO 6 INCHES OF RAIN. ONE SUCH AREA WAS THOREAU WHERE SIGNIFICANT FLASH FLOODING HAS BEEN REPORTED TODAY. NOW THE FOCUS IS WHERE ADJUST HIGHEST POPS. CURRENTLY THE RADAR AND SATELLITE TRENDS FOCUS THE BEST COVERAGE OVER THE NORTHERN MTS AND STILL SOMEWHAT ALONG THE CONT DVD. THE 01Z HRRR AND 03Z RUC HANDLE THE CURRENT PRECIP WELL SO HAVE GONE IN THIS DIRECTION ONCE AGAIN TONIGHT. THEREFORE EXPECTING CURRENT NMRS COVERAGE ACROSS THE NORTH TO MOVE SLOWLY ESE INTO THE JEMEZ AND SOUTHERN SANGRES AND THE NE HIGHLANDS. PLACED SCATTERED COVERAGE THERE WITH ISOLD AT BEST FOR THE REMAINDER OF THE AREA. GUYER && .PREV DISCUSSION...610 PM MDT SUN AUG 5 2012... .AVIATION... 00Z TAF CYCLE ANOTHER FAIRLY ACTIVE CONVECTIVE DAY WAS REALIZED TODAY...BUT MAINLY JUST ACROSS THE NW THIRD OR SO OF THE STATE. THROUGH THIS EVE EXPECT SCT TO LOCALLY NUMEROUS SHRA AND TSRA AGAIN MOSTLY WEST AND NORTH NM. STRONGEST STORMS WILL LIKELY ALSO REMAIN MAINLY N AND W WITH LOCALIZED AND RELATIVELY SHORT LIVED MVFR CIGS AS WELL AS ISOLATED INSTANCES OF SMALL HAIL ASSOCIATED WITH STRONGER TSRA. TSRA MENTIONED ONLY IN SAF...LVS AND FMN TO ACCOUNT FOR BEST CHANCE LOCALES FOR TSRA. OTHERWISE IN AREAS ALREADY WORKED OVER IN WEST OR OTHERWISE TOO UNLIKELY TO PICK UP A TSRA IN CENTRAL AND E NM EITHER VCSH MENTIONED OR NOTHING AT ALL.. MOST IF NOT ALL TSRA SHOULD DISSIPATE BY OR WITHIN A COUPLE HOURS OF MIDNIGHT. WHILE SOME SHRA AND TSRA LIKELY TO DEVELOP MON MAINLY AFTER 19Z...COVERAGE AND INTENSITY SHOULD OVERALL BE A LITTLE LESS THAN TODAY. 43 .PREV DISCUSSION...315 PM MDT SUN AUG 5 2012... AS EXPECTED...SOMEWHAT OF A SLOW START TO THE SHOWER AND THUNDERSTORM DEVELOPMENT THIS AFTERNOON. PRECIPITABLE WATER VALUES IN THE FLASH FLOOD WATCH AREA REMAIN ABOUT 120-150 PERCENT OF NORMAL SO NO CHANGES TO THE ONGOING WATCH. LOW LEVEL GULF MOISTURE COMBINING WITH MID LEVEL MONSOON MOISTURE PLUME TO GET PWAT VALUES UP THIS HIGH. STORMS FIRING OVER THE WEST-CENTRAL MTNS ARE MOVING NORTH AROUND 15 KTS BUT TRAINING OF SHOWERS AND STORMS OVER THE SAME AREA/DRAINAGE REMAINS THE MAIN CONCERN. DOPPLER RADAR ESTIMATING OVER 2 INCHES OF RAIN HAVE FALLEN FROM ONE CELL OR CELLS TRAINING OVER THOREAU IN THE PAST HOUR AND A HALF. ELSEWHERE...STORMS ARE DEVELOPING OVER THE NORTHERN MOUNTAINS AND SUSPECT THAT STORMS WILL BEGIN FIRING OVER OTHER MOUNTAIN LOCATIONS SHORTLY...AS MORE SURFACE HEATING ALLOWS UPDRAFTS TO PUNCH THROUGH THE SUBSIDENCE INVERSION AROUND 14K FEET AGL. MODELS ARE IN VERY GOOD TO EXCELLENT AGREEMENT FOR MONDAY...SLIDING THE CENTER OF THE UPPER LEVEL HIGH OVER NORTHWEST NM. STEERING LEVEL FLOW GRADUALLY BECOMES NORTH/NORTHWESTERLY OVER THE NORTH AND NORTHEAST TO EASTERLY OVER THE SOUTHWEST MOUNTAINS. RESIDUAL MOISTURE WILL COMBINE WITH THE ELEVATED HEAT SOURCES/MOUNTAINS TO GET SCATTERED SHOWERS AND THUNDERSTORMS GOING MONDAY AFTERNOON. HIGH RESOLUTION MODELS INDICATING THAT STORMS MOVING SOUTH FROM THE JEMEZ MOUNTAINS COULD BRING A ROUND OF THUNDERSTORMS TO BERNALILLO AND THE ALBUQUERQUE METRO AREA EARLY MONDAY EVENING. AND WITH STORM MOTION BECOMING NORTHWESTERLY MONDAY LATE AFTERNOON AND EVENING...SHOWERS AND STORMS WILL MOVE OFF THE SANGRE DE CRISTOS OUT ONTO THE NORTHEAST HIGHLANDS AND PLAINS. TUESDAY LOOKS VERY SIMILAR TO MONDAY WITH ONE EXCEPTION. AS THE UPPER HIGH CENTER SHIFTS FAR ENOUGH WESTWARD...NELY FLOW AT ALL LEVELS DEVELOPS AND BRINGS GULF MOISTURE TO THE NERN PLAINS AND CENTRAL HIGHLANDS TUESDAY AFTERNOON AND EVENING. THE MOIST NELY FLOW COMBINES WITH A WEAK WAVE TRANSLATING AROUND THE UPPER HIGH TO BRING HIGHER STORM CHANCES FROM THE CENTRAL MOUNTAINS EWD TUESDAY AFTERNOON AND EVENING. SIMILAR UPPER LEVEL AND SURFACE PATTERN CONTINUES INTO WEDNESDAY. DRIER MID AND UPPER LEVEL AIR BEGINS TO FILTER INTO CENTRAL AND SRN NM THURSDAY...WITH THE BEST THUNDERSTORM CHANCES OVER THE NRN MOUNTAINS. FRIDAY LOOKS...AT THIS POINT...LIKE THE DOWN DAY FOR THUNDERSTORMS THIS WEEK...OUTSIDE OF THE NRN AND WRN MOUNTAINS BUT WITH A NELY STEERING LEVEL FLOW IN PLACE...CANNOT RULE OUT SLIGHT CHANCES/ISOLATED STORMS FOR THE CENTRAL VALLEYS AS STORMS MOVE SOUTHWESTWARD. EXCELLENT AGREEMENT IN THE MEDIUM RANGE OPERATIONAL MODELS EXISTS FOR NEXT WEEKEND. UPPER HIGH REMAINS FAR ENOUGH NORTHWEST OF THE STATE FOR OCCASIONAL SHORT-WAVES/DISTURBANCES TO ROTATE AROUND THE HIGH CENTER AND INITIATE A NORTHEAST TO ELY SURFACE FLOW OVER THE REGION...RECHARGING SFC MOISTURE. THIS NW FLOW ALOFT IS QUITE THE FAVORABLE PATTERN FOR THE NORTHEAST AND EAST CENTRAL PLAINS. LONG RANGE FORECASTS GET QUITE INTERESTING. LATEST ECMWF FORECASTS A MAJOR BLOCKING PATTERN (OMEGA BLOCK) OVER THE GULF OF ALASKA...FORCING A LARGE AND UNSEASONABLY DEEP CLOSED UPPER LEVEL LOW OVER THE PACNW. THIS PATTERN WOULD FORCE THE UPPER HIGH BACK OVER THE SRN PLAINS STATES AND POSSIBLY OPEN THE DOOR FOR A DEEP SOUTHERLY FETCH OF SUBTROPICAL/TROPICAL MOISTURE INTO THE STATE. WE SHALL SEE. 33 .FIRE WEATHER... SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE QUITE NUMEROUS GOING INTO THE EVENING...ESPECIALLY ACROSS WESTERN AND NORTHERN PARTS OF NEW MEXICO. THIS BOOST IN STORM COVERAGE AND THE RELATIVELY LARGE FOOTPRINT OF WETTING RAINS RECEIVED YESTERDAY SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS THROUGH THE NEAR TERM. BACK DOOR FRONT ADVANCED TOWARD ARIZONA...AND SHOULD CONTINUE TO PROVIDE SOME UPSLOPE TO AID IN THUNDERSTORM DEVELOPMENT ALONG AND NEAR THE CONTINENTAL DIVIDE. TEMPERATURES HAVE ALSO FALLEN BACK TO MORE REASONABLE VALUES AND CLOSER TO SEASONAL AVERAGES...ESPECIALLY IN THE EASTERN PLAINS. THIS ALONG WITH INCREASED CLOUD COVER AND ANTECEDENT RAIN CONDITIONS HAS KEPT RELATIVE HUMIDITY AT OR ABOVE 30 PERCENT IN THE FORECAST AREA...AND ANY GAP/CANYON WINDS HAVE DIMINISHED. GOOD TO EXCELLENT RH RECOVERY CAN BE EXPECTED TONIGHT AND INTO EARLY MONDAY MORNING. AS HIGH PRESSURE ALOFT REGAINS SOME SYMMETRY OVER THE FOUR CORNERS...IT WILL STEER FEWER STORMS INTO THE NORTHERN AND WESTERN MOUNTAINS OF NEW MEXICO ON MONDAY. ONCE THE HIGH NUDGES NORTHWESTWARD INTO TUESDAY...ANOTHER BACK DOOR FRONT WILL SLIDE INTO THE NORTHEASTERN PLAINS OF NEW MEXICO. AT THIS POINT...THE DIRECTIONAL SHIFT IN THE WINDS APPEARS TO BE A PRIMARY IMPACT AS NO MAJOR INCREASE IN DEWPOINTS IS ANTICIPATED. ANY UPTICK IN STORM COVERAGE IN THE NORTHEAST ON TUESDAY WOULD BE FAIRLY SUBTLE. FROM MID WEEK AND THROUGH THE EXTENDED FORECAST PERIOD VERY LITTLE MOVEMENT OF THE UPPER LEVEL HIGH IS FORESEEN. THIS WILL LIKELY DRIVE STORMS MOSTLY TO THE NORTHERN AND WESTERN MOUNTAINS OF NEW MEXICO WITH LESS THAN AVERAGE COVERAGE. && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ GUYER
AREA FORECAST DISCUSSION
NWS BUFFALO NY
951 PM EDT TUE AUG 7 2012 .SYNOPSIS... FAIR WEATHER WILL CONTINUE THROUGH TONIGHT AS HIGH PRESSURE SLIDES OFF THE EAST COAST...THEN A WEAK COLD FRONT WILL CROSS THE AREA ON WEDNESDAY ALONG WITH A LOW CHANCE OF SOME SHOWERS AND THUNDERSTORMS. MAINLY DRY WEATHER WEDNESDAY NIGHT WILL THEN GIVE WAY TO INCREASINGLY UNSETTLED CONDITIONS THURSDAY AND FRIDAY AS LOW PRESSURE LIFTS NORTHEAST FROM THE OHIO VALLEY. && .NEAR TERM /THROUGH WEDNESDAY/... HIGH PRESSURE WILL SLIDE OFF THE EAST COAST TONIGHT...ALLOWING A WEAK COLD FRONT TO SLOWLY APPROACH THE AREA FROM THE UPPER GREAT LAKES AND CENTRAL ONTARIO. RADAR SHOWS LIMITED SHOWERS ACROSS SOUTHWESTERN ONTARIO...BUT GIVEN THE NORTHEAST MOVEMENT AND OVERALL WEAKENING TREND...EXPECT WESTERN NEW YORK TO STAY DRY OVERNIGHT. THE HRRR IS IN AGREEMENT WITH 12Z/18Z MODEL CONSENSUS IN KEEPING WESTERN NEW YORK DRY...WITH THE MAIN IMPACT OF THE FRONTAL BOUNDARY A MODEST INCREASE IN CLOUDS. WITH A WARMER START AND LIGHT TO MODEST SOUTHERLY FLOW EXPECTED TO BE IN PLACE...TONIGHT`S LOWS SHOULD WIND UP WARMER THAN THIS MORNING`S... WITH READINGS RANGING FROM THE MID AND UPPER 50S ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND NORTH COUNTRY...TO THE LOWER 60S ALONG THE LAKE PLAINS. AS IS TYPICAL FOR THIS TIME OF YEAR...THE COMBINATION OF RELATIVELY COOL AIR TEMPS AND WARMER RIVER WATERS WILL PROBABLY ALSO LEAD TO THE DEVELOPMENT OF SOME PATCHY VALLEY FOG ACROSS THE SOUTHERN TIER OVERNIGHT. ON WEDNESDAY...THE AFOREMENTIONED COLD FRONT WILL GRADUALLY SLIDE SOUTHEAST ACROSS THE FORECAST AREA...AND SHOULD EXIT TO OUR SOUTHEAST BY LATE AFTERNOON/EARLY EVENING. WHILE THIS FEATURE WILL HAVE SOME MID LEVEL SUPPORT IN THE FORM OF A MODEST MID LEVEL SHORTWAVE...MOISTURE ALONG IT SHOULD REMAIN LIMITED...WHICH IN TURN WILL ACT TO LIMIT THE POTENTIAL FOR PRECIPITATION. AS HAS RECENTLY BEEN THE CASE...THE 12Z MODELS CONTINUE TO SHOW SOME VARIANCE ON THE PRECIP POTENTIAL FOR TOMORROW GIVEN DIFFERING AMOUNTS OF MOISTURE RETURN ALONG THE FRONT...WITH THE GFS REMAINING MOST AMBITIOUS /AND PROBABLY OVERLY SO GIVEN ITS TRACK RECORD THIS SUMMER/...THE NAM KEEPING US COMPLETELY DRY...AND THE ECMWF/GEM BOTH LYING SOMEWHERE IN BETWEEN. GIVEN THE DIFFERENCES AND THE UNIMPRESSIVE NATURE OF THE FRONT...FEEL A MIX OF SLIGHT CHANCE TO LOW CHANCE POPS REMAINS IN ORDER. WHEN TAKING BOTH THE TIMING OF THE FRONT AND LOCAL LAKE INFLUENCES INTO CONSIDERATION...AT THIS POINT IT APPEARS THAT THE BEST CHANCES FOR ANY ISOLATED TO SCATTERED CONVECTION WILL COME TOMORROW AFTERNOON ACROSS INTERIOR SECTIONS SOUTH OF LAKE ONTARIO...WHEN DAYTIME HEATING SHOULD LEAD TO A SLIGHTLY GREATER POTENTIAL FOR SHOWERS/STORMS ALONG AND AHEAD OF THE FRONT. WILL THEREFORE INDICATE CHANCE POPS FOR THIS AREA AND TIME FRAME...AND SLIGHT CHANCE OR LESS OTHERWISE. AS FOR SEVERE POTENTIAL...UNIMPRESSIVE WIND PROFILES AND LIMITED MOISTURE SHOULD KEEP ANY STORMS THAT DO FORM GARDEN VARIETY IN NATURE. WITH 850 MB TEMPS IN THE +15C TO +17C RANGE AND AT LEAST PARTIAL SUNSHINE AGAIN EXPECTED...MOST LOCATIONS SHOULD SEE HIGHS IN THE MID TO UPPER 80S ON WEDNESDAY...WITH A FEW LOCATIONS ACROSS THE FINGER LAKES POSSIBLY TICKING THE 90 DEGREE MARK. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... WEAK COOL FRONT WILL CONTINUE TO MAKES IT WAY SLOWLY THROUGH THE REGION WEDNESDAY NIGHT WITH THE POTENTIAL FOR SOME SPOTTY CONVECTION...ALTHOUGH EXPECT MUCH OF THE AREA TO REMAIN DRY AS SOME LOW LEVEL DRY AIR IS EXPECTED TO ADVECT SOUTHWARD BEHIND THE FRONTAL BOUNDARY. THE FRONT IS EXPECTED STALL OUT JUST TO THE SOUTH OF THE STATE BY THURSDAY WITH OUR ATTENTION TURNING UPSTREAM TO AN IMPRESSIVE UPPER LEVEL SYSTEM. A FAIRLY STRONG AND COMPACT UPPER LEVEL JET STREAK IS EXPECTED TO DIVE DOWN THE UPPER RIDGE INTO THE MID MISSISSIPPI VALLEY...AND EVENTUALLY CARVE OUT AN UNSEASONABLY STRONG 500 MB HEIGHT MINIMUM ACROSS THE SOUTHERN GREAT LAKES BY THURSDAY NIGHT. THE INITIAL POSITIVELY TILTED ORIENTATION OF THIS TROUGH THURSDAY AFTERNOON WILL RESULT IN MAIN SURFACE WAVE TO TAKE SHAPE UPSTREAM OVER THE OHIO VALLEY. THE DEEPENING MID/UPPER LEVEL SYSTEM WILL ALLOW FOR STRENGTHENING FRONTOGENETIC FLOW ON THE PRE-EXISTING LOW/MID LEVEL BAROCLINIC ZONE ON THURSDAY WHICH SHOULD RESULT IN CHANCES OF SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING PRIME AFTERNOON HEATING AND SOUTHERN PORTIONS OF THE AREA GIVEN INCREASING LARGE SCALE FORCING AND STRENGTHENING LOW/MID LEVEL FRONTOGENESIS. SEVERE THREAT LOOKS LIMITED...ALTHOUGH THERE SHOULD BE ADEQUATE ATMOSPHERIC DESTABILIZATION BY AFTERNOON...BUT OVERALL SHEAR PROFILES ARE LACKING. THE FRONTAL BOUNDARY LOOKS TO SHIFT NORTHWARD AND GETS STRETCHED OUT RIGHT ACROSS WESTERN AND CENTRAL NEW YORK THURSDAY NIGHT AND FRIDAY. THE CLOSED MID-UPPER LEVEL CIRCULATION PUSHING THROUGH THE OHIO VALLEY WILL ADVECT PLENTY OF MOISTURE INTO OUR REGION WITH PRECIPITATION WATER VALUES...EVENTUALLY INCREASING TO NEAR 1.75 INCHES BY FRIDAY. IMPRESSIVE ISENTROPIC ASCENT DEVELOPING AHEAD OF THE FRONTAL WAVE APPROACHING THE AREA COMBINED WITH FAVORABLE UPPER LEVEL DYNAMIC SUPPORT...WITH OUR AREA WITHIN THE FAVORABLE RIGHT UPPER JET ENTRANCE REGION ENHANCING DEEP LAYER LIFT. THIS ALL SUPPORTS THE POTENTIAL FOR THE DEVELOPMENT OF WIDESPREAD PRECIPITATION...WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL THURSDAY NIGHT THROUGH FRIDAY NIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... GENERAL MEDIUM RANGE MODEL CONSENSUS IS TO SHOW DEEP CIRCULATION CONTINUING AT THE START OF THE PERIOD OVER SOUTHERN CANADA AND THE GREAT LAKES REGION...AS THE SURFACE WAVE LIFTS INTO NEW ENGLAND WITH ATTENDANT COLD FRONT PUSHING THROUGH THE REGION. DEEPEST MOISTURE LOOKS TO PULL EASTWARD ACROSS EASTERN NEW YORK INTO NEW ENGLAND... WHILE THE BROAD CYCLONIC FLOW ALOFT AND ASSOCIATED COLD POOL ALOFT CONTINUES TO BRING THE THREAT FOR AT LEAST SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS DURING THE DAY SATURDAY. DEEP TROUGHING STARTS TO LIFT OUT SUNDAY WITH THE THREAT FOR SOME LINGERING SHOWERS ACROSS EASTERN SECTIONS SUNDAY...BUT TRENDING TO DRY OUT ACROSS THE WEST. FOR MONDAY AND TUESDAY...INCREASING RIDGING DURING THIS PERIOD IS EXPECTED TO RESULT IN FAIR WEATHER WITH A WARMING TREND. HIGHS MONDAY IN THE MIDDLE 70S TO AROUND 80....WARMING INTO THE UPPER 70S TO MIDDLE 80S BY TUESDAY. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... A FRONTAL BOUNDARY WILL CROSS THE REGION ON WEDNESDAY...BUT SHOWERS AND THUNDERSTORM ACTIVITY IS EXPECTED TO BE QUITE SPARSE. THE BEST CHANCE FOR THIS WILL BE INLAND FROM THE LAKES DURING WEDNESDAY AFTERNOON. OTHERWISE...EXPECT MAINLY VFR CONDITIONS UNTIL THEN. TEMPERATURE DEW POINT SPREADS AT JHW HAVE NARROWED THROUGH 00Z...AND ARE LESS THAN THEY WERE LAST NIGHT WHEN THERE IS NO FOG. THEREFORE...DID INTRODUCE FOG INTO THE TAF FOR LATE TONIGHT. OUTLOOK... WEDNESDAY NIGHT...MAINLY VFR. THURSDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. THURSDAY NIGHT AND FRIDAY...IFR/MVFR WITH SHOWERS AND THUNDERSTORMS LIKELY. SATURDAY AND SUNDAY...VFR/MVFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. && .MARINE... RELATIVELY QUIET MARINE CONDITIONS WILL CONTINUE THROUGH TONIGHT AS HIGH PRESSURE SLIDES OFF THE EAST COAST. A WEAK COLD FRONT WILL THEN CROSS THE LOWER LAKES ON WEDNESDAY WITH PERHAPS A STRAY SHOWER OR THUNDERSTORM...BEFORE INCREASINGLY UNSETTLED WEATHER WORKS INTO THE REGION THURSDAY AND FRIDAY. IN TERMS OF WINDS AND WAVES...EXPECT LIGHT TO MODEST WINDS AND WAVES TO REMAIN UNDER 2 FEET THROUGH WEDNESDAY NIGHT. AFTER THAT TIME...A STRENGTHENING NORTH TO NORTHEASTERLY FLOW WILL BRING AN INCREASING POTENTIAL FOR ADVISORY-CRITERIA WINDS AND WAVES THURSDAY INTO FRIDAY. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...JJR NEAR TERM...APFFEL/JJR SHORT TERM...TMA LONG TERM...TMA AVIATION...APFFEL MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
320 PM EDT MON AUG 6 2012 .SYNOPSIS... AN UPPER LEVEL TROUGH APPROACHING FROM THE NORTHWEST THIS EVENING....WILL DRIFT EAST ACROSS THE CAROLINAS AND SOUTHERN VIRGINIA TONIGHT THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 320 PM MONDAY... A WEAK COLD FRONT WEST OF THE MOUNTAINS WILL STALL FROM EASTERN TN TO NORTHERN VA THIS EVENING...WHILE THE ASSOCIATED UPPER SHEAR AXIS SLIPS EAST INTO CENTRAL NC. CONVECTION HAS DEVELOPED ALONG A DIFFERENTIAL HEATING NEAR THE NC/VA BORDER FROM WIDESPREAD CLOUD COVER THAT HAS BEEN DRIFTING ALONG AND EAST OF THE FRONTAL ZONE...AND ALSO OVER SOUTHEAST NC AND COASTAL SC. THE COVERAGE OF SHOWERS AND STORMS WILL INCREASE FROM THE WESTERN PIEDMONT TO THE NORTHERN COASTAL PLAIN BY 21Z...AND THEN SLOWLY PUSH EAST ACROSS THE PIEDMONT THIS EVENING AS THE SHEAR AXIS MOVES OVER THE AREA. MLCAPE HAS BEEN LIMITED TO LESS THAN 1000 J/KG OVER MOST OF CENTRAL NC THUS FAR...AND WEAK MID LEVEL FLOW HAS THE 0-6KM EFFECTIVE SHEAR WELL BELOW 20KT. WITH VERY LITTLE DOWNDRAFT CAPE AND SOUNDINGS BECOMING INCREASINGLY MOIST ADIABATIC DUE TO PW VALUES OF OVER 2 INCHES...THE SEVERE THREAT IS LOW THIS EVENING OUTSIDE OF A MORE INTENSE STORM WILL A PRECIP LOADED DOWNBURST. SOME MINOR FLASH FLOODING IS POSSIBLE...MAINLY IN URBAN AREAS THIS EVENING AS FLASH FLOOD GUIDANCE IS RELATIVELY HIGH AREAWIDE. TONIGHT... AS THE RIBBON OF VORTICITY ASSOCIATED WITH THE SHEAR AXIS SETTLES INTO CENTRAL NC TONIGHT...SOME OF THE CAMS ALONG WITH THE HRRR SHOW THE FOCUS FOR PRECIP SETTING UP ALONG OR JUST WEST OF US HWY 1. WEAK LAPSE RATES ALOFT AND LIMITED INSTABILITY...COVERAGE SHOULD DECREASE AFTER MIDNIGHT...BUT SCATTERED SHOWERS AND A FEW ISOLATED STORMS WILL BE POSSIBLE OVERNIGHT. LOWS IN THE LOWER 70S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 320 PM MONDAY... THE UPPER LEVEL SHEAR AXIS AND AXIS OF HIGHER PW WILL SHIFT SLIGHTLY EAST ON TUESDAY...AND WITH IT THE FOCUS FOR GREAT COVERAGE OF SHOWERS AND STORMS. CONDITIONS WILL BE VERY SIMILAR TO TODAY WITH WEAK INSTABILITY AND SHEAR...BUT HIGH PW AND RELATIVELY SLOW MOVEMENT OF CELLS...WHICH WILL LEAD TO MAINLY AN ISOLATED FLASH FLOODING THREAT. ONE FEATURE TO NOTE IS AN AREA OF CONVECTION OVER THE FL PANHANDLE AND ITS ASSOCIATED VORT MAX...WHICH MODELS SHOW BEING DRAWN NORTH ACROSS GA AND SC ON TUESDAY. THE GFS HAS THE MOST AGGRESSIVE NORTHWARD TRACK AND BRINGS IT ACROSS THE NC COASTAL PLAIN LATE TUESDAY NIGHT INTO WEDNESDAY. HOWEVER...THERE IS TOO MUCH MODEL SPREAD TO PUT MUCH FAITH IN HOW IT MIGHT IMPACT CONVECTION TUESDAY NIGHT. FOR NOW...WE WILL CONTINUE TO SHOW 70-80 POPS ACROSS THE EAST TUESDAY AFTERNOON...TRENDING DOWNWARD TUESDAY NIGHT BUT WITH AT LEAST CHANCE POPS OVERNIGHT. UNDER MORE WIDESPREAD CLOUD COVER...HIGHS SHOULD BE A FEW DEGREES COOLER THAN TODAY...AND MOST GUIDANCE GIVES LOW TO MID 80S. LOWS TUESDAY NIGHT IN THE UPPER 60S TO LOWER 70S. WEDNESDAY THROUGH THURSDAY NIGHT: THE MID/LOW LEVEL TROUGH WEAKENS AND STALLS OVER THE EAST COAST ON WEDNESDAY...BRINGING THE BEST CHANCES FOR PRECIP FROM THE COASTAL PLAIN EASTWARD. THE REMNANTS OF THE SURFACE TROUGH WILL MOVE OFFSHORE WEDNESDAY NIGHT AND THURSDAY AHEAD OF OUR NEXT LOW PRESSURE/FRONTAL SYSTEM. THIS SHOULD YIELD A BREAK IN THE PRECIPITATION WEDNESDAY NIGHT AND INTO THURSDAY...WITH MORE SHOWERS AND THUNDERSTORMS POSSIBLE THURSDAY AFTERNOON AND INTO THURSDAY NIGHT. HAVE TRENDED MORE TOWARD THE MAV FOR TEMPS...HIGHS WEDNESDAY IN THE MID 80S WITH LOWS OVERNIGHT IN THE UPPER 60S TO LOW 70S. HIGHS THURSDAY SLIGHTLY WARMER...MID TO UPPER 80S WITH OVERNIGHT LOWS IN THE LOW 70S && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 320 PM MONDAY... A COLD FRONT ASSOCIATED WITH AN ANOMALOUSLY STRONG LOW PRESSURE SYSTEM WILL IMPACT CENTRAL NC AT THE END OF THE WEEK. THE UPPER LEVEL LOW IS EXPECTED TO DEVELOP OVER CANADA ON WEDNESDAY AND TRACK SOUTH AND EAST THROUGH MICHIGAN EARLY FRIDAY AND DEEPEN AS IT MOVES OVER THE GREAT LAKES INTO THE WEEKEND. HAVE MAINLY GONE WITH A BLEND OF THE ECMWF AND THE 12Z GFS AS THEY ARE IN FAIRLY GOOD AGREEMENT AND SEEM TO HANDLE THE LOW PRESSURE SYSTEM THE BEST. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM SHOULD MOVE INTO THE AREA AROUND MID DAY FRIDAY...BRINGING WITH IT THE POTENTIAL FOR STRONG TO SEVERE STORMS TO DEVELOP. THE 12Z GFS GENERATES 1500-2000 J/KG OF SURFACE BASED CAPE OVER CENTRAL NC FRIDAY AFTERNOON...0-6 KM BULK SHEAR VALUES OF 30-40 KTS...MID LEVEL LAPSE RATES OF 6-7 DEGREES C/KM...AND PRECIPITABLE WATER VALUES OVER 2 INCHES. BOTH MODELS SHOW THE MAIN PRECIP AXIS MOVING THROUGH CENTRAL NC FROM THE NW THROUGH APPROX 12Z SATURDAY. THE FRONT COULD THEN LINGER OVER THE COAST THROUGH THE END OF THE WEEKEND...LEADING TO A CONTINUED CHANCE FOR SHOWERS AND STORMS OVER THE COASTAL PLAIN DURING THAT TIME. EXPECT HIGHS IN THE MID TO UPPER 80S THROUGH SUNDAY...WITH SLIGHTLY COOLER TEMPS FOR MONDAY...LOW TO MID 80S. OVERNIGHT LOWS RANGING FROM THE UPPER 60S TO LOW 70S THROUGH THE END OF THE PERIOD. && .AVIATION /18Z MONDAY THROUGH FRIDAY/... AS OF 140 PM MONDAY... MOSTLY 3-4K FT CEILINGS ARE CURRENTLY OBSERVED ACROSS CENTRAL NC WITH A FEW AREAS OF SHOWERS AND ISOLATED THUNDERSTORMS NEAR KGSO/KINT AND NORTH OF KRDU. A COLD FRONT WILL PUSH INTO WESTERN NC THIS EVENING BUT CONTINUE TO WEAKEN AND WASH OUT OVER CENTRAL NC BY TUESDAY. SHOWERS AND STORMS ARE EXPECTED TO BECOME MORE NUMEROUS ALONG THE WEAK FRONT. WHERE SHOWERS ARE HEAVIEST...STRONG GUSTY WINDS AND IFR...OR LOWER.... CEILINGS/VSBYS WILL BE POSSIBLE. THE TIMING OF THESE SHOWERS AND STORMS IS DIFFICULT TO PIN DOWN...BUT THE BEST TIME FRAME APPEARS AFTER 20Z TODAY AND INTO THE OVERNIGHT HOURS...POSSIBLY DIMINISHING FROM WEST TO EAST AFTER MIDNIGHT. IFR CEILINGS MAY THEN DEVELOP BY 09Z...WITH MODELS SHOWING THE GREATEST PROBABILITY AT KGSO AND KINT. SHOWERS AND STORMS ARE EXPECTED TO DEVELOP ALONG THE REMNANTS OF THE FRONT ON TUESDAY...WITH THE GREATEST COVERAGE OVER EASTERN NC. ANY MORNING STRATUS SHOULD LIFT BUT MAY HOLD AT OR JUST BELOW 3K FT GIVEN THE MOIST AIRMASS IN PLACE. OUTLOOK... THE THREAT FOR SCATTERED...MAINLY AFTERNOON AND EVENING SHOWERS AND T-STORMS...WILL RETURN THURSDAY AND FRIDAY. IN ADDITION THERE WILL BE THE LIKELIHOOD OF SUB-VFR FOG AND CEILINGS DURING THE PRE-DAWN THROUGH EARLY MORNING HOURS EACH DAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM..SMITH SHORT TERM...SMITH/KMC LONG TERM...SMITH AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
305 PM EDT MON AUG 6 2012 .SYNOPSIS... A FRONT WILL REMAIN STATIONARY TO THE NORTHWEST OF THE REGION...AND THIS WILL ALLOW FOR A MOIST AND UNSTABLE AIR MASS TO REMAIN IN PLACE THROUGH THE END OF THE WEEK. A SECOND FRONT WILL APPROACH THE AREA AND BECOME STATIONARY ALONG THE COAST THIS WEEKEND. THERE IS A CHANCE OF THUNDERSTORMS AND SHOWERS EACH DAY WITH THE BEST CHANCES ARE TUESDAY AND THIS WEEKEND. && .NEAR TERM /THROUGH 6 AM TUESDAY/... AS OF 300 PM MONDAY...THE FORECAST SETUP IS QUITE SIMILAR TO YESTERDAY. SURGE OF TROPICAL MOISTURE HAS LEAD TO A BAND OF SHOWERS ALONG THE COAST...MAINLY INITIATED BY LL CONVG. THIS AREA OF RAIN IS BEING ADVECTED FURTHER INLAND WHILE CELL MOTION IS TO THE NORTHEAST. THE ACTUAL SEABREEZE HAS HAD VERY WEAK RADAR SIGNATURE TODAY AND IS BETTER DEMARCATED IN VIS SAT IMAGERY...TO THE EAST OF WHICH CLOUD COVER IS VERY MUCH DECREASED. SIMILAR TO YESTERDAY THE VERY NEAR TERM FORECAST WILL SHOW THE WET WEATHER CONTINUE TO DRIFT WESTWARD AND START TO DIMINISH WITH THE DIURNAL CYCLE. THE HRRR PERFORMED QUITE WELL YESTERDAY AND HAS THIS LINE BECOME MUCH MORE BROKEN BY 22Z AND EVEN MORESO TOWARDS SUNSET. SOME QUESTION AS TO WHETHER OR NOT PRECIP DEVELOPS OVER WATER DURING THE OVERNIGHT HOURS. MODEL GUIDANCE NOT TOO EXCITED ABOUT THE PROSPECT BUT THE SLIGHT CHANCE POPS FROM THE PREVIOUS FORECAST SEEMS PLAUSIBLE ENOUGH. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...WITH STATIONARY FRONT BACK TO THE WEST AND DEEP MOISTURE IS IN PLACE OVER THE AREA...CONDITIONS CONTINUE TO FAVOR A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE REGION TUESDAY AND WEDNESDAY. THE MODELS ARE INDICATING A SHORT WAVE TO CROSS THE REGION ON TUESDAY AND WITH THIS LIFT SHOULD ENTICE THE DEVELOPMENT OF RAIN FOR THE ENTIRE COUNTY WARNING AREA. THE MEAN STORM MOTION IS FROM THE SOUTHWEST JUST BELOW 10 KNOTS AND WITH SOME HEAVY DOWNPOURS EXPECT THE FLOW MAYBE QUICK ENOUGH TO HOLD OFF THE CHANCES FOR ANY TYPE OF FLOODING ON TUESDAY. THE SOUTHWEST WINDS ALOFT PATTERN HOLDS UP INTO WEDNESDAY SO EXPECT CHANCES OF RAIN TO CONTINUE. TEMPERATURES ARE EXPECTED REMAIN IN THE MID TO UPPER 80S AND LOWS IN THE MIDDLE 70S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...PATTERN ALOFT WILL REMAIN AMPLIFIED THROUGH THE PERIOD WITH RIDGING OVER THE WEST AND TROUGHING OVER THE EAST. EARLY IN THE PERIOD TROUGHING IS ON THE WEAK SIDE...BUT IMPRESSIVE SHORTWAVE DROPPING DOWN THE EAST SIDE OF THE WESTERN RIDGE WILL DRIVE A COLD FRONT INTO THE SOUTHEAST AND HELP AMPLIFY THE 5H TROUGH OVER THE WEEKEND. WITH 5H TROUGH AXIS REMAINING OVER THE OH AND TN VALLEYS GULF MOISTURE WILL CONTINUE TO STREAM INTO THE REGION. COLD FRONT STALLS ACROSS THE AREA SUN THEN STARTS TO WASH OUT MON. DEEP MOISTURE...DIVERGENCE ALOFT...DIURNAL HEATING...AND CONVERGENCE ALONG THE SEA BREEZE AND PIEDMONT TROUGH/COLD FRONT WILL KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. HIGHEST POP DURING THE PERIOD WILL LIKELY BE SAT...THOUGH WEAK SHORTWAVES THU AND/OR FRI COULD PRODUCE SIGNIFICANT COVERAGE. TEMPERATURES WILL BE WITHIN A DEGREE OR TWO OF CLIMO THROUGH THE PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...CONVECTION FIRING ALONG THE RESULTANT THAT WILL PUSH WESTWARD WITH TIME...SLOWER THAN YESTERDAY DUE TO THE SOUTHWEST FLOW ALOFT. LOOK FOR THE SHOWERS AND ISOLATED THUNDERSTORMS TO END AROUND 22Z...WITH MAINLY VFR CONDITIONS EXPECTED THROUGH THE OVERNIGHT HOURS. TIME HEIGHT INDICATES MID AND HIGH CLOUDS WILL BE ON THE INCREASE AS A FRONTAL BOUNDARY THAT HAS BEEN JUST WEST OF THE REGION FOR SEVERAL DAYS FINALLY MOVES IN. TUESDAY...AGAIN A MID OR HIGH CLOUD CEILING WITH SCATTERED CONVECTION AROUND. MAINLY SOUTHWEST FLOW THROUGH THE PERIOD...MORE SOUTHERLY ALONG THE COAST. EXTENDED OUTLOOK...MVFR/IFR VSBYS AND LOW CEILINGS FROM BR/FG POSSIBLE EACH MORNING WITH DAILY THREAT FOR DIURNALLY DRIVEN CONVECTION EACH DAY. && .MARINE... AS OF 1030 AM MONDAY/THROUGH TONIGHT/...THE PRESSURE GRADIENT OVER THE LANDMASS WILL BE QUITE LIGHT THROUGH THE PERIOD. HIGH PRESSURE ACROSS THE WEST AND CENTRAL ATLANTIC WILL STILL BE THE DOMINANT WIND AND WAVE MAKER THEN. A SOUTH TO SOUTHWESTERLY WIND WILL BE CAPPED AT JUST 10KT. WIND WAVES IN THE 2 TO 3 FT RANGE WILL BE COMPRISED OF BOTH THE LIGHT WIND WAVE AND SOME 9 SEC SWELL ENERGY. SHORT TERM /6 AM TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...SOUTH TO SOUTHWEST WINDS OF 10 TO 15 KNOTS WILL CONTINUE OVER THE WATERS THROUGH THE PERIOD AS A STATIONARY FRONT REMAINS INLAND THROUGH THE PERIOD. SEAS WILL REMAINS AROUND 3 FEET WITH AN INCREASE TO 4 TO 5 FEET AT 20 MILES OFF THE COAST LATE WEDNESDAY EVENING. THIS WILL BE RELATED TO AN INCREASE IN THE SOUTHERLY WINDS. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 3 PM MONDAY...SOUTHWEST FLOW CONTINUES THROUGH THE PERIOD...THOUGH WITH SPEEDS INCREASING AS A COLD FRONT APPROACHES THE REGION FROM THE NORTHWEST. WINDS 10 TO 15 KT THU INTO THU NIGHT INCREASE TO 15 TO 20 FRI AND FRI NIGHT AS GRADIENT TIGHTENS UP AND LOW LEVEL JET DEVELOPS. FRONT MOVES INTO THE REGION SAT RELAXING PRESSURE GRADIENT AND SHIFTING STRONGEST LOW LEVEL JETTING NORTH AND EAST. THIS WILL ALLOW WINDS TO DROP BACK CLOSER TO 15 KT. SEAS 2 TO 4 FT THU WILL BUILD WITH INCREASING WINDS FRI AND FRI NIGHT. ISOLATED 6 FT MAY DEVELOP WELL AWAY FROM THE COAST. HEADLINES ARE POSSIBLE FOR BOTH FRI AND FRI NIGHT...BUT LOW CONFIDENCE WHETHER IT WILL BE SCA OR SCEC. REDUCTION IN WINDS SAT/SAT NIGHT ALLOWS SEAS TO DROP BACK INTO THE 2 TO 4 FT RANGE WITH SOME ISOLATED 5 FT POSSIBLE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...REK/MBB SHORT TERM...HAWKINS LONG TERM...III AVIATION...DL
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
1024 AM CDT MON AUG 6 2012 .UPDATE... REDUCED/REMOVED RAIN CHANCES WEST OF AN ENID TO OKLAHOMA CITY TO ATOKA LINE THROUGH 1 PM CDT. ALSO...NUDGED HIGHS UPWARD OVER NORTHERN OKLAHOMA AND TWEAKED SKY COVER AND WINDS THIS AFTERNOON. && .DISCUSSION... HOT CONDITIONS WILL AGAIN PREVAIL THIS AFTERNOON WITH LOW CHANCES FOR SHOWERS AND STORMS MAINLY SOUTHWEST OF AN ALVA TO CHICKASHA TO ADA LINE. THROUGH 1 PM CDT...MAINLY HOT AND DRY CONDITIONS ARE EXPECTED. CONFINED 20 PERCENT RAIN CHANCES TO FAR WESTERN OKLAHOMA AND PARTS OF WESTERN NORTH TEXAS SOUTH OF A KNOX CITY TO WICHITA FALLS LINE WHERE LATEST SATELLITE IMAGERY DEPICTED SOME MID LEVEL CLOUDINESS. LATEST HRRR RUNS SUGGESTED ISOLATED DEVELOPMENT NEAR I-35...WHICH SEEMS TO BE VERY POORLY HANDLED AS THERE ARE NO CUMULUS CLOUDS AND WEAK LAPSE RATES IN THESE AREAS. THIS AFTERNOON AND EVENING...LATEST NAM12 AND HRRR RUNS INDICATED ISOLATED TO PERHAPS SCATTERED SHOWERS AND STORMS WILL DEVELOP OVER MAINLY WESTERN AND SOUTHERN OKLAHOMA AS WELL AS WESTERN NORTH TEXAS. FIRST DEVELOPMENT MAY OCCUR IN THE 1 TO 3 PM TIME FRAME NEAR A GAGE TO WICHITA FALLS TO DURANT LINE ONCE CONVECTIVE TEMPERATURES IN THE 95 TO 100 DEGREE RANGE ARE MET. GUSTY WINDS...POSSIBLY SEVERE OF 60 MPH OR GREATER DUE TO STEEP LOW LEVEL LAPSE RATES AND DCAPE VALUES AROUND 1500 J/KG...AND LIGHTNING STRIKES WHICH CAN IGNITE FIRES WILL BE THE MAIN HAZARDS. RAINFALL AMOUNTS WILL GENERALLY BE LIGHT...THOUGH ONE OR TWO LOCATIONS MAY RECEIVE 0.50 INCH OR MORE. DUE TO FAIRLY WEAK SHEAR...STORMS SHOULD REMAIN UNORGANIZED AND MOVE SOUTHEAST 15 TO 20 MPH. STORMS WILL WEAKEN AROUND SUNSET WITH THE LOSS OF DAYTIME HEATING. HIGHS TODAY SHOULD REACH THE CENTURY MARK OR HIGHER IN MOST LOCATIONS. WILL BE CLOSE TO HEAT ADVISORY CRITERIA WITH HEAT INDICES NEAR 105 DEGREES ACROSS WESTERN NORTH TEXAS AND SOUTHERN OKLAHOMA...BUT HELD OFF WITH ISSUANCE DUE TO LOW CONFIDENCE. PRODUCTS HAVE BEEN UPDATED. MBS && .PREV DISCUSSION... /ISSUED 640 AM CDT MON AUG 6 2012/ AVIATION... 06/12Z TAFS...VFR CONDITIONS ARE EXPECTED TO PREVAIL. ISOLATED OR SCATTERED STORMS POSSIBLE TODAY INTO THIS EVENING BUT PROBABILITY TOO LOW TO MENTION IN THIS ISSUANCE. UPDATE... ISOLATED STORM NEAR WATONGA DEVELOPING EARLIER AND A BIT FARTHER NORTH THAN PREVIOUSLY EXPECTED SO WILL UPDATE TO SPREAD LOW POPS FARTHER NORTH AND EAST INTO OKC METRO. LATEST HRRR OUTPUT FAIRLY AGGRESSIVE WITH STORMS ACROSS CENTRAL INTO SOUTH-CENTRAL OKLAHOMA DURING THE MORNING. THIS IS LIKELY OVERDONE AND WILL NOT GET TOO CARRIED AWAY WITH PROBABILITIES AND WILL LEAVE HIGHER POPS ACROSS SOUTHERN OKLAHOMA INTO WRN N TEXAS LATE TODAY. PREV DISCUSSION... /ISSUED 426 AM CDT MON AUG 6 2012/ DISCUSSION... OVERALL LITTLE CHANGE TO GOING FORECAST OTHER THAN INCLUDING LOW PROBABILITIES FOR THUNDERSTORMS LATER TODAY NEAR STALLED FRONTAL BOUNDARY NEAR RED RIVER VALLEY. TEMPERATURES FORECAST TO WARM NEXT COUPLE OF DAYS AND ALL MODEL GUIDANCE STILL COOLS US DOWN A BIT WEDNESDAY AND THURSDAY WITH WEAK FRONTAL BOUNDARY AND INCREASE IN CLOUD COVER. SCATTERED STORMS STILL APPEAR POSSIBLE LATE TUESDAY THROUGH WEDNESDAY WITH WEAK S/WV PROGRESSING AROUND UPPER RIDGE...BUT WRF/GFS MODELS LIKELY TOO AGGRESSIVE WITH WIDESPREAD RAIN DUE TO FORECASTING TOO MUCH BOUNDARY LAYER MOISTURE. WILL KEEP POPS SIMILAR TO PREVIOUS FORECAST THROUGH LATE WEDNESDAY BEFORE ANOTHER FEW DAYS OF WARMING TEMPS. MODELS TRYING TO COME INTO BETTER AGREEMENT WITH A STRONGER FRONT IN THE FRIDAY-SATURDAY TIME FRAME. WILL NOT MENTION POPS THIS FAR OUT BUT WILL CONTINUE SLIGHT COOLING TREND INTO NEXT WEEKEND. ALTHOUGH WINDS FOR MOST OF THE WEEK WILL BE ON THE LIGHT SIDE... LOW AFTERNOON HUMIDITIES AND HOT TEMPS WILL KEEP WILDFIRE CONCERNS ELEVATED. ALSO...DESPITE MAX HEAT INDEX AND LOW TEMP FORECASTS NEAR OR MEETING CRITERIA...WE HELD OFF ON ISSUING HEAT ADVISORY FOR SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS DUE TO UNCERTAINTY OF MID-WEEK TEMPS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 102 77 103 78 / 10 10 10 20 HOBART OK 102 74 103 75 / 30 20 20 30 WICHITA FALLS TX 106 79 107 79 / 30 20 20 30 GAGE OK 99 71 102 71 / 30 10 30 30 PONCA CITY OK 102 72 103 74 / 0 10 10 20 DURANT OK 102 76 103 78 / 20 20 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 17/03
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
640 AM CDT MON AUG 6 2012 .AVIATION... 06/12Z TAFS...VFR CONDITIONS ARE EXPECTED TO PREVAIL. ISOLATED OR SCATTERED STORMS POSSIBLE TODAY INTO THIS EVENING BUT PROBABILITY TOO LOW TO MENTION IN THIS ISSUANCE. && .UPDATE... ISOLATED STORM NEAR WATONGA DEVELOPING EARLIER AND A BIT FARTHER NORTH THAN PREVIOUSLY EXPECTED SO WILL UPDATE TO SPREAD LOW POPS FARTHER NORTH AND EAST INTO OKC METRO. LATEST HRRR OUTPUT FAIRLY AGGRESSIVE WITH STORMS ACROSS CENTRAL INTO SOUTH-CENTRAL OKLAHOMA DURING THE MORNING. THIS IS LIKELY OVERDONE AND WILL NOT GET TOO CARRIED AWAY WITH PROBABILITIES AND WILL LEAVE HIGHER POPS ACROSS SOUTHERN OKLAHOMA INTO WRN N TEXAS LATE TODAY. && .PREV DISCUSSION... /ISSUED 426 AM CDT MON AUG 6 2012/ DISCUSSION... OVERALL LITTLE CHANGE TO GOING FORECAST OTHER THAN INCLUDING LOW PROBABILITIES FOR THUNDERSTORMS LATER TODAY NEAR STALLED FRONTAL BOUNDARY NEAR RED RIVER VALLEY. TEMPERATURES FORECAST TO WARM NEXT COUPLE OF DAYS AND ALL MODEL GUIDANCE STILL COOLS US DOWN A BIT WEDNESDAY AND THURSDAY WITH WEAK FRONTAL BOUNDARY AND INCREASE IN CLOUD COVER. SCATTERED STORMS STILL APPEAR POSSIBLE LATE TUESDAY THROUGH WEDNESDAY WITH WEAK S/WV PROGRESSING AROUND UPPER RIDGE...BUT WRF/GFS MODELS LIKELY TOO AGGRESSIVE WITH WIDESPREAD RAIN DUE TO FORECASTING TOO MUCH BOUNDARY LAYER MOISTURE. WILL KEEP POPS SIMILAR TO PREVIOUS FORECAST THROUGH LATE WEDNESDAY BEFORE ANOTHER FEW DAYS OF WARMING TEMPS. MODELS TRYING TO COME INTO BETTER AGREEMENT WITH A STRONGER FRONT IN THE FRIDAY-SATURDAY TIME FRAME. WILL NOT MENTION POPS THIS FAR OUT BUT WILL CONTINUE SLIGHT COOLING TREND INTO NEXT WEEKEND. ALTHOUGH WINDS FOR MOST OF THE WEEK WILL BE ON THE LIGHT SIDE... LOW AFTERNOON HUMIDITIES AND HOT TEMPS WILL KEEP WILDFIRE CONCERNS ELEVATED. ALSO...DESPITE MAX HEAT INDEX AND LOW TEMP FORECASTS NEAR OR MEETING CRITERIA...WE HELD OFF ON ISSUING HEAT ADVISORY FOR SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS DUE TO UNCERTAINTY OF MID-WEEK TEMPS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 102 77 103 78 / 20 10 10 20 HOBART OK 102 74 103 75 / 30 20 20 30 WICHITA FALLS TX 106 79 107 79 / 30 20 20 30 GAGE OK 99 71 102 71 / 20 10 30 30 PONCA CITY OK 98 72 103 74 / 0 10 10 20 DURANT OK 102 76 103 78 / 20 20 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 26/11
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
551 AM CDT MON AUG 6 2012 .UPDATE... ISOLATED STORM NEAR WATONGA DEVELOPING EARLIER AND A BIT FARTHER NORTH THAN PREVIOUSLY EXPECTED SO WILL UPDATE TO SPREAD LOW POPS FARTHER NORTH AND EAST INTO OKC METRO. LATEST HRRR OUTPUT FAIRLY AGGRESSIVE WITH STORMS ACROSS CENTRAL INTO SOUTH-CENTRAL OKLAHOMA DURING THE MORNING. THIS IS LIKELY OVERDONE AND WILL NOT GET TOO CARRIED AWAY WITH PROBABILITIES AND WILL LEAVE HIGHER POPS ACROSS SOUTHERN OKLAHOMA INTO WRN N TEXAS LATE TODAY. && .PREV DISCUSSION... /ISSUED 426 AM CDT MON AUG 6 2012/ DISCUSSION... OVERALL LITTLE CHANGE TO GOING FORECAST OTHER THAN INCLUDING LOW PROBABILITIES FOR THUNDERSTORMS LATER TODAY NEAR STALLED FRONTAL BOUNDARY NEAR RED RIVER VALLEY. TEMPERATURES FORECAST TO WARM NEXT COUPLE OF DAYS AND ALL MODEL GUIDANCE STILL COOLS US DOWN A BIT WEDNESDAY AND THURSDAY WITH WEAK FRONTAL BOUNDARY AND INCREASE IN CLOUD COVER. SCATTERED STORMS STILL APPEAR POSSIBLE LATE TUESDAY THROUGH WEDNESDAY WITH WEAK S/WV PROGRESSING AROUND UPPER RIDGE...BUT WRF/GFS MODELS LIKELY TOO AGGRESSIVE WITH WIDESPREAD RAIN DUE TO FORECASTING TOO MUCH BOUNDARY LAYER MOISTURE. WILL KEEP POPS SIMILAR TO PREVIOUS FORECAST THROUGH LATE WEDNESDAY BEFORE ANOTHER FEW DAYS OF WARMING TEMPS. MODELS TRYING TO COME INTO BETTER AGREEMENT WITH A STRONGER FRONT IN THE FRIDAY-SATURDAY TIME FRAME. WILL NOT MENTION POPS THIS FAR OUT BUT WILL CONTINUE SLIGHT COOLING TREND INTO NEXT WEEKEND. ALTHOUGH WINDS FOR MOST OF THE WEEK WILL BE ON THE LIGHT SIDE... LOW AFTERNOON HUMIDITIES AND HOT TEMPS WILL KEEP WILDFIRE CONCERNS ELEVATED. ALSO...DESPITE MAX HEAT INDEX AND LOW TEMP FORECASTS NEAR OR MEETING CRITERIA...WE HELD OFF ON ISSUING HEAT ADVISORY FOR SOUTHERN OKLAHOMA AND WESTERN NORTH TEXAS DUE TO UNCERTAINTY OF MID-WEEK TEMPS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 102 77 103 78 / 20 10 10 20 HOBART OK 102 74 103 75 / 30 20 20 30 WICHITA FALLS TX 106 79 107 79 / 30 20 20 30 GAGE OK 99 71 102 71 / 20 10 30 30 PONCA CITY OK 98 72 103 74 / 0 10 10 20 DURANT OK 102 76 103 78 / 20 20 10 10 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 26/11
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
305 PM CDT MON AUG 6 2012 .SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...CONVECTION THIS AFTERNOON HAS DIMINISH AS THE SEA-BREEZE MOVES INLAND. MAIN THINKING IS THAT THE BEST DYNAMICS REMAIN TO THE SOUTH WHERE A STRONGER VORTICITY MAX SHOWS UP IN THE RUC ANALYSIS...AND BIT STRONGER CAP IS HOLDING ON ACROSS OUR REGION. WITH THE LOSS OF HEATING LATE THIS EVENING...PRECIPITATION WILL REMAIN LOW AND HAVE KEPT MENTION OUT OF THE FORECAST. DECENT MOISTURE IN PLACE EXPECTED TO STAY AROUND FOR TOMORROW TO KEEP SLIGHT CHANCE OF PRECIPITATION...BEGINNING OVER THE COASTAL WATERS TUESDAY MORNING THEN AFTERNOON CONVECTION AGAIN FOR THE AFTERNOON HOURS. COULD SEE A BIT OF LOWER VISIBILITIES WILL BE POSSIBLE JUST BEFORE SUNRISE GIVEN THE LIGHT WINDS...HIGH DEW POINT VALUES AND GENERALLY CLEAR SKIES. HOWEVER...CONFIDENCE REMAINS LOW ON FOG DEVELOPMENT OVERNIGHT. AFTERNOON TEMPERATURES WILL ONCE AGAIN RUN ABOVE GUIDANCE/SEASONAL AVERAGES. OVERALL...A PERSISTENT FORECAST FROM WHAT WE HAVE SEE THE PAST FEW DAYS...JUST A BIT LESS IN THE WAY OF CONVECTION WITH LACK OF MID/UPPER LEVEL SUPPORT. && .LONG TERM (WEDNESDAY THROUGH MONDAY)...CONCUR WITH THE DETERMINISTIC GFS/ECMWF AND GFS ENSEMBLE MEAN THAT THE UPPER RIDGE WILL CONTINUE TO MOVE TOWARD THE NW BEFORE BECOMING QUASI- STATIONARY. SUFFICIENT MOISTURE/INSTABILITY WILL CONTRIBUTE TO ISOLD CONVECTION PRIMARILY OVER THE NERN SECTIONS/ADJACENT MSA WEDNESDAY/THURSDAY. THE FOREGOING MODELS PROG AN UPPER DISTURBANCE TO MOVE ACRS THE CNTRL/NRN PLAINS WEDNESDAY/THURSDAY WHICH WILL CONTRIBUTE TO A WEAK FRONTAL BOUNDARY WHICH MAY ENTER CNTRL/SRN TX FRIDAY/SATURDAY (ALONG WITH ASSOCIATED HIGH PW VALUES OWING TO MSTR CONVERGENCE.) FURTHER...BASED ON THE CURRENT ERNESTO FCST TRACK... THE NRN EDGE OF COPIOUS MSTR FROM ERNESTO EXPECTED TO ENTER THE CWA/MSA COMMENCING LATE THURSDAY. THUS WILL MAINTAIN AT LEAST ISOLD CONVECTION FRIDAY/SATURDAY. NOT CONFIDENCE ENOUGH TO FCST PCPN SUNDAY/MONDAY. NO SIGNIFICANT CHANGE TO TEMPS DRG THE PERIOD EXCEPT FOR SLIGHT DECREASE IN RESPONSE TO ERNESTO MSTR. ANTICIPATE MAX HEAT INDEX VALUES AROUND 105F DRG THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 75 96 77 95 75 / 10 20 10 10 10 VICTORIA 73 95 75 95 74 / 10 20 10 20 10 LAREDO 78 102 79 102 79 / 10 10 10 10 10 ALICE 74 100 74 99 74 / 10 20 10 10 10 ROCKPORT 79 91 79 89 78 / 20 20 10 20 10 COTULLA 74 101 75 101 75 / 10 10 10 10 10 KINGSVILLE 74 98 76 97 75 / 10 20 10 10 10 NAVY CORPUS 79 90 80 88 80 / 10 20 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ RG/82...SHORT TERM WC/87...LONG TERM
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1221 PM CDT MON AUG 6 2012 .AVIATION... CONCERNS THROUGH SUNSET WILL BE ISOLATED STORM DEVELOPMENT AND BACKING OF WINDS FROM WSW TO SELY BY 00Z TUESDAY. WEAK SHORTWAVE CONTINUES TO DROP SWD ACROSS E TX WITH A WEAKENING MORNING STORMS OCCURRING BETWEEN KSLR AND KPSN. ALL TERMINALS ARE JUST OUTSIDE OF THE HIGH CLOUD CANOPY WILL LIKELY SEE DIFFERENTIAL HEATING AND AGEOSTROPHIC LIFTING PROCESSES AS THE AFTERNOON PROGRESSES. THERE ARE INDICATIONS FROM THE RAP AND NORMAN WRF MODELS THAT ISOLATED STORMS WILL BECOME MORE EVIDENT BY MAX HEATING OR MID AFTERNOON. WITH A VERY MOIST AND TROPICAL AIRMASS IN PLACE...PRECIP LOADING COULD RESULT IN GUSTY DOWNBURSTS IN EXCESS OF 40 KTS POSSIBLE. ONLY DIFFERENCE IS WACO WILL LIKELY SEE THEIR BEST POTENTIAL LATER IN DAY...BETWEEN 21Z-01Z. OTHERWISE...VFR FORECAST CONTINUES WITH LIGHT SWLY FLOW BECOMING SELY BY SUNSET...THEN SWLY BY DAYBREAK TUESDAY. 05/ && .UPDATE... A WEAK BOUNDARY REMAINS ACROSS THE NORTHEASTERN ZONES AT MIDDAY. THE MAIN CHANGE TO THE FORECAST WAS TO ADD ISOLATED THUNDERSTORMS TO THE WEST WHERE THE HIGH RESOLUTION RAPID REFRESH IS SHOWING SOME THUNDERSTORM DEVELOPMENT LATER THIS AFTERNOON. HAVE ALSO ADJUSTED THE HOURLY TEMPERATURES IN THE NORTHEAST WHERE CLOUD COVER AND EARLIER PRECIPITATION HAVE SLOWED THE WARM UP. 58 && .PREV DISCUSSION... /ISSUED 413 AM CDT MON AUG 6 2012/ NORTH TO NORTHWEST FLOW ALOFT WILL REMAIN OVER NORTH TEXAS THROUGH THE WEEK AS UPPER LEVEL HIGH PRESSURE REMAINS CENTERED NEAR THE FOUR CORNERS REGION. THIS PATTERN WILL RESULT IN SEASONALLY HOT TEMPERATURES AND SOME LOW RAIN/THUNDERSTORM CHANCES THROUGH MUCH OF THE WEEK. A WEAK COLD FRONT THAT HAD MOVED INTO NORTH TEXAS ON SUNDAY WAS LOCATED NEAR A SHERMAN TO SULPHUR SPRINGS LINE EARLY THIS MORNING. THIS FRONT IS PROGGED TO SLOWLY BACKDOOR THE EASTERN COUNTIES OF NORTH TEXAS THROUGH TUESDAY. THE FRONT WILL CONTINUE TO ACT AS A FOCUSING MECHANISM FOR SCATTERED SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. THERE IS ALSO A SMALL CHANCE THAT SOME SHOWERS AND THUNDERSTORMS COULD MOVE ACROSS THE WESTERN AND NORTHERN PORTIONS OF NORTH TEXAS DURING THE OVERNIGHT/MORNING HOURS TONIGHT THROUGH THURSDAY MORNING...AS AFTERNOON CONVECTION ACROSS THE CENTRAL PLAINS MOVES SOUTH/SOUTHEAST DURING THE OVERNIGHT HOURS. FOR NOW WE WILL KEEP ALL POPS LOW WITH ONLY WEAK FORCING EXPECTED AND A VERY DRY SOLUTION FROM THE ECMWF. UPPER LEVEL HIGH PRESSURE WILL BUILD BACK TO THE EAST BY THE WEEKEND WHICH SHOULD DECREASE RAIN CHANCES DUE TO INCREASED LARGE SCALE SUBSIDENCE. HIGH TEMPERATURES THROUGH THE WEEK WILL RANGE FROM THE MIDDLE 90S TO AROUND 101 WITH OVERNIGHT LOWS FROM THE MIDDLE 70S TO NEAR 80. THE ONLY LOCATIONS THAT WILL SEE AFTERNOON HEAT INDEX VALUES UP TO 106 WILL BE THE EASTERN ZONES DUE TO SLIGHTLY BETTER MOISTURE. THEREFORE...WILL KEEP THE HEAT ADVISORY THROUGH TUESDAY JUST FOR THE EXTREME EASTERN COUNTIES OF NORTH TEXAS. HOWEVER...OVERNIGHT LOWS MAY BE SLIGHTLY SHY OF REACHING CRITERIA IN SOME SPOTS. 79 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 102 80 101 79 101 / 20 20 10 20 20 WACO, TX 100 77 102 80 100 / 20 20 10 10 20 PARIS, TX 98 76 99 75 98 / 20 20 10 10 20 DENTON, TX 102 77 102 76 101 / 20 10 10 20 20 MCKINNEY, TX 99 76 99 76 99 / 20 20 10 20 20 DALLAS, TX 101 82 101 80 100 / 20 20 10 20 20 TERRELL, TX 100 76 100 76 98 / 20 20 20 20 20 CORSICANA, TX 100 76 100 76 99 / 20 20 20 10 20 TEMPLE, TX 101 76 100 76 99 / 20 10 10 20 20 MINERAL WELLS, TX 101 78 101 78 102 / 10 20 20 20 20 && .FWD WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 8 PM CDT TUESDAY FOR TXZ107-122-123-135- 146>148-160>162-174-175. && $$ 05/58
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1020 PM EDT TUE AUG 7 2012 .SYNOPSIS... A PERIOD OF UNSETTLED WEATHER WILL CONTINUE THIS WEEK AS A FRONTAL BOUNDARY OSCILLATES ACROSS THE MID ATLANTIC REGION. A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION ON FRIDAY...BRINGING A GENEROUS COVERAGE OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND DRIER WEATHER IS EXPECTED BY THE START OF THE NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 1000 PM EDT TUESDAY... THE FRONTAL BOUNDARY PER LATEST MSAS THETA-E/LI GRADIENT LIES FROM ERN KY ENE INTO CENTRAL VA. SHOWERS AND STORMS REMAIN ISOLATED AT BEST WITH BEST CONCENTRATION ACROSS THE NC FOOTHILLS. STORM MOVEMENT HAS BEEN ALL OVER THE PLACE WITH A WEAK FLOW. 00Z SOUNDINGS FROM RNK/GSO SHOW STORM MOTION OF 3 KNOTS OR LESS. LUCKILY HAVE NOT HAD STORMS LINGERING OVER ONE AREA TOO LONG AS THEY TEND TO FADE AFTER AN HOUR. WILL SEE A WEAKENING TREND TO THE ACTIVITY OVERNIGHT AND THINK A SLOW PUSH SOUTHEAST OF THE THETA-E RIDGE WILL KEEP AT LEAST A LOW CHANCE/SLIGHT CHANCE POPS AROUND ALL NIGHT FROM SOUTHSIDE VA/NW NC PIEDMONT WEST TO THE GRAYSON HIGHLANDS/NC MTNS. THE OTHER ISSUE TONIGHT WILL BE FOG AND HOW DENSE WILL IT GET. THE DENSE CANOPY OF CIRROSTRATUS CONTINUES ACROSS THE ENTIRE FORECAST AREA. MODELS SHOW DRIER AIR SNEAKING INTO THE MTNS AFTER 09Z...SO WILL SEE SOME CLEARING. WILL HAVE TO WATCH SFC OBS AND SAT TRENDS FOR POTENTIAL DENSE FOG ADVISORY. SOME SCHOOLS IN NC ARE STARTING IN THE MORNING SO FOG WILL CAUSE A PROBLEM THERE POTENTIALLY. WILL KEEP THE MENTION IN HWO FOR NOW. RAISED TEMPS/DEWPOINTS UP A DEGREE OR TWO OVERNIGHT MAINLY EAST OF THE NEW RIVER VALLEY WHERE THINK MORE CLOUDS ARE GOING TO LINGER THROUGH WED MORNING. PREVIOUS VALID DISCUSSION... ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR AS PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH. HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED SHOWERS SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING FARTHER TO OUR SOUTH...MORE SUNSHINE SHOULD YIELD HIGH TEMPERATURES ON WEDNESDAY ABOUT THREE TO FIVE DEGREES WARMER THAN TODAY. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 242 PM EDT TUESDAY... CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE SHORT TERM PERIOD AS AN UPPER LEVEL TROF AMPLIFIES OVER THE GREAT LAKES AND INTO THE OHIO VALLEY BY FRIDAY. IN ADVANCE OF THIS SYSTEM...TEMPERATURES SHOULD WARM TOWARD THE WARMER NAM MOS VALUES ON THURSDAY AS THE LOW LEVEL THERMAL RIDGE NOSES INTO OUR AREA. BEST CHANCES FOR THUNDERSTORMS ON THURSDAY WILL BE IN THE WEST AS A LEAD SHORT WAVE (OVERDONE BY THE GFS) APPROACHES OUR AREA AND INTERACTS WITH A MODERATELY UNSTABLE AIRMASS. KEPT POPS IN THE EASTERN PORTION OF THE FORECAST AREA ON THURSDAY AS WEAK LOW LEVEL CONVERGENCE ALONG A LEE-SIDE TROF SHOULD GENERATE SCATTERED CONVECTION. THIS CONVECTION MAY LINGER A FEW HOURS BEYOND SUNDOWN THURSDAY NIGHT WITH SUPPORT FROM THE WEAK UPPER LEVEL WAVE MOVING THROUGH. THE TREND OF THE MODELS FOR FRIDAY`S SYSTEM HAS BEEN TO SLOW ITS EASTWARD PROGRESS SLIGHTLY. BY 00Z (8 PM EDT) SATURDAY...MOST MODELS SHOW THE COLD FRONT STILL WEST OF OUR FORECAST AREA. THE POTENTIAL EXISTS FOR STRONG TO SEVERE STORMS TO ERUPT IN ADVANCE OF THIS SYSTEM AS THE AREA COMES UNDER THE INFLUENCE OF THE RR QUAD OF AN UPPER LEVEL JET ROTATING AROUND THE EASTERN SIDE OF THE APPROACHING SHORT WAVE TROF. THE BIGGEST QUESTION CONCERNING THE POTENTIAL FOR SEVERE WEATHER WILL BE THE INSTABILITY. CLOUDS ON FRIDAY SHOULD KEEP HIGH TEMPS BELOW THURSDAY`S EXPECTED HIGHS AND MAY KEEP INSTABILITY DOWN. THE GFS CRAVEN SIG SVR PARAMETER FORECAST KEEPS THE HIGHEST POTENTIAL FOR SEVERE WEATHER TO OUR SOUTHEAST...WHERE INSTABILITY IS FORECAST TO BE HIGHER. CONSIDERING THE STRENGTH OF THIS UPPER LEVEL SYSTEM...WILL KEEP MENTION OF SVR WX IN THE HWO...ALONG WITH THE THREAT FOR HEAVY RAIN WITH PWATS EXPECTED TO EXCEED 2 INCHES IN THE EAST. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 242 PM EDT TUESDAY... THE LONG RANGE MODELS ARE IN GOOD AGREEMENT THAT THE EASTERN U.S. REMAINS UNDER THE INFLUENCE OF AN UPPER TROF THAT DE-AMPLIFIES WITH TIME. AHEAD OF THE UPPER TROF...A STRONG COLD FRONT WILL SWEEP THROUGH FRIDAY NIGHT. THE 00Z ECMWF HOLDS MORE UPPER LEVEL ENERGY ON THE WEST SIDE OF THE UPPER TROF AND KEEPS PRECIP LINGERING IN THE FAR EASTERN PORTION OF OUR FORECAST AREA ON SATURDAY. SO WE HAVE DELAYED THE ENDING TIME OF THE PRECIP UNTIL MIDDAY SATURDAY. OTHERWISE...UPSLOPE RAIN SHOWERS CAN BE EXPECTED UNDER THE TROF AXIS AND LOW LEVEL NORTHWEST WINDS. DRIER...COOLER AND LESS HUMID AIR WILL INVADE THE REGION LATE SATURDAY INTO SUNDAY. THE GEFS SHOWS 850MB TEMPS BY 18Z SATURDAY WILL BE 1-2 STANDARD DEVIATIONS BELOW NORMAL. SO...LEANED TOWARD THE COOLER ECMWF VALUES FOR TEMPS SATURDAY NIGHT THROUGH SUNDAY NIGHT. TEMPERATURES WILL GRADUALLY WARM MONDAY AND TUESDAY AS THE UPPER LEVEL TROF RELAXES...BUT INDIVIDUAL SHORT WAVES MOVING THROUGH AN UPPER LEVEL NORTHWEST FLOW COMBINED WITH A WEAK SOUTHEAST FLOW WILL GENERATE AFTERNOON SHOWERS AND STORMS. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... AS OF 715 PM EDT TUESDAY... SOME STORMS WHICH HAVE DEVELOPED TONIGHT HAVE BEEN AWAY FROM ANY TERMINALS. THEY WILL WEAKEN QUICKLY AFTER SUNSET. MANY AREAS WILL SEE VALLEY AND RIVER FOG DEVELOPING OVERNIGHT...WITH MOST AREAS MVFR FOR VSBYS BY SUNRISE WITH ISOLATED IFR OR LOWER. VLIFR/LIFR CIGS AREA ALSO POSSIBLE WITHIN THE VALLEYS. ANY SUB-VFR CONDITIONS SHOULD IMPROVE TO VFR BY 13-14Z...9-10AM...WEDNESDAY A FRONTAL BOUNDARY WILL HOVER AROUND THE REGION THROUGH THE WEEKEND WITH PERIODIC WAVES OF ENERGY RIDING ALONG IT. LOOK FOR AT LEAST ISOLATED DIURNAL CONVECTION DURING THIS TIME PERIOD...WITH FRIDAY INTO SATURDAY HAVING A BETTER CHANCE OF ORGANIZED CONVECTION AS A LOW DEVELOPS OVER THE MIDWEST AND EJECTS THE FRONT EASTWARD AS A STRONG COLD FRONT. LATE NIGHT/EARLY MORNING MOUNTAIN AND RIVER VALLY FOG IS ALSO EXPECTED MOST NIGHTS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/WP SHORT TERM...PH LONG TERM...PH AVIATION...DS/KM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
726 PM EDT TUE AUG 7 2012 .SYNOPSIS... A PERIOD OF UNSETTLED WEATHER WILL CONTINUE THIS WEEK AS A FRONTAL BOUNDARY OSCILLATES ACROSS THE MID ATLANTIC REGION. A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION ON FRIDAY...BRINGING A GENEROUS COVERAGE OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND DRIER WEATHER IS EXPECTED BY THE START OF THE NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 720 PM EDT TUESDAY... STORM MOVEMENT REMAINS SLOW IN MOST LOCATIONS AS FRONT STAYS ACROSS OUR NRN CWA. MLCAPES OF 2000+ RESIDE IN THE PIEDMONT AND ESPECIALLY ACROSS THE NC FOOTHILLS/PIEDMONT. HAD ONE STORM FIRE UP NEAR GRETNA AND SO FAR ONLY REPORTS OF PEA SIZE OR SLIGHTLY LARGER HAIL HAVE BEEN RECEIVED. WILL KEEP HIGHER POPS IN THE SRN FORECAST AREA THIS EVENING...AND KEEP SKY COVER HIGHER PER THICKER CIRRUS OVERHEAD. MODELS SHOWING COVERAGE OF PRECIP ACROSS MOST OF THE AREA TO DISSIPATE AFTER MIDNIGHT. PREVIOUS VALID DISCUSSION... FRONT WILL CONTINUE TO SLOWLY HEAD SOUTH THROUGH THE NIGHT...SO THAT HIGH PRESSURE WILL BE NOSING SOUTH INTO THE REGION BY WEDNESDAY. THIS HIGH WILL BRING A TREND TOWARDS DECREASING CLOUDS OVERNIGHT INTO EARLY WEDNESDAY MORNING. LIGHT WINDS...AND LINGERING BOUNDARY LAYER MOISTURE BELOW THE NOCTURNAL INVERSION WILL HELP GENERATE AREAS OF FOG TONIGHT ACROSS A GENEROUS PORTION OF THE AREA. WHILE THERE IS BOUND TO BE SOME DENSE FOG...CONFIDENCE IN IT BEING WIDESPREAD ARE NOT HIGH AT THIS TIME. WILL HIGHLIGHT THE POTENTIAL FOR SOME DENSE FOG TONIGHT IN ALL BUT THE BLUEFIELD TO TAZEWELL AREA. LOW TEMPERATURES TONIGHT WILL AVERAGE THREE TO FIVE DEGREES COOLER THAN READINGS EXPERIENCED THIS MORNING. ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR AS PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH. HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED SHOWERS SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING FARTHER TO OUR SOUTH...MORE SUNSHINE SHOULD YIELD HIGH TEMPERATURES ON WEDNESDAY ABOUT THREE TO FIVE DEGREES WARMER THAN TODAY. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 242 PM EDT TUESDAY... CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE SHORT TERM PERIOD AS AN UPPER LEVEL TROF AMPLIFIES OVER THE GREAT LAKES AND INTO THE OHIO VALLEY BY FRIDAY. IN ADVANCE OF THIS SYSTEM...TEMPERATURES SHOULD WARM TOWARD THE WARMER NAM MOS VALUES ON THURSDAY AS THE LOW LEVEL THERMAL RIDGE NOSES INTO OUR AREA. BEST CHANCES FOR THUNDERSTORMS ON THURSDAY WILL BE IN THE WEST AS A LEAD SHORT WAVE (OVERDONE BY THE GFS) APPROACHES OUR AREA AND INTERACTS WITH A MODERATELY UNSTABLE AIRMASS. KEPT POPS IN THE EASTERN PORTION OF THE FORECAST AREA ON THURSDAY AS WEAK LOW LEVEL CONVERGENCE ALONG A LEE-SIDE TROF SHOULD GENERATE SCATTERED CONVECTION. THIS CONVECTION MAY LINGER A FEW HOURS BEYOND SUNDOWN THURSDAY NIGHT WITH SUPPORT FROM THE WEAK UPPER LEVEL WAVE MOVING THROUGH. THE TREND OF THE MODELS FOR FRIDAY`S SYSTEM HAS BEEN TO SLOW ITS EASTWARD PROGRESS SLIGHTLY. BY 00Z (8 PM EDT) SATURDAY...MOST MODELS SHOW THE COLD FRONT STILL WEST OF OUR FORECAST AREA. THE POTENTIAL EXISTS FOR STRONG TO SEVERE STORMS TO ERUPT IN ADVANCE OF THIS SYSTEM AS THE AREA COMES UNDER THE INFLUENCE OF THE RR QUAD OF AN UPPER LEVEL JET ROTATING AROUND THE EASTERN SIDE OF THE APPROACHING SHORT WAVE TROF. THE BIGGEST QUESTION CONCERNING THE POTENTIAL FOR SEVERE WEATHER WILL BE THE INSTABILITY. CLOUDS ON FRIDAY SHOULD KEEP HIGH TEMPS BELOW THURSDAY`S EXPECTED HIGHS AND MAY KEEP INSTABILITY DOWN. THE GFS CRAVEN SIG SVR PARAMETER FORECAST KEEPS THE HIGHEST POTENTIAL FOR SEVERE WEATHER TO OUR SOUTHEAST...WHERE INSTABILITY IS FORECAST TO BE HIGHER. CONSIDERING THE STRENGTH OF THIS UPPER LEVEL SYSTEM...WILL KEEP MENTION OF SVR WX IN THE HWO...ALONG WITH THE THREAT FOR HEAVY RAIN WITH PWATS EXPECTED TO EXCEED 2 INCHES IN THE EAST. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 242 PM EDT TUESDAY... THE LONG RANGE MODELS ARE IN GOOD AGREEMENT THAT THE EASTERN U.S. REMAINS UNDER THE INFLUENCE OF AN UPPER TROF THAT DE-AMPLIFIES WITH TIME. AHEAD OF THE UPPER TROF...A STRONG COLD FRONT WILL SWEEP THROUGH FRIDAY NIGHT. THE 00Z ECMWF HOLDS MORE UPPER LEVEL ENERGY ON THE WEST SIDE OF THE UPPER TROF AND KEEPS PRECIP LINGERING IN THE FAR EASTERN PORTION OF OUR FORECAST AREA ON SATURDAY. SO WE HAVE DELAYED THE ENDING TIME OF THE PRECIP UNTIL MIDDAY SATURDAY. OTHERWISE...UPSLOPE RAIN SHOWERS CAN BE EXPECTED UNDER THE TROF AXIS AND LOW LEVEL NORTHWEST WINDS. DRIER...COOLER AND LESS HUMID AIR WILL INVADE THE REGION LATE SATURDAY INTO SUNDAY. THE GEFS SHOWS 850MB TEMPS BY 18Z SATURDAY WILL BE 1-2 STANDARD DEVIATIONS BELOW NORMAL. SO...LEANED TOWARD THE COOLER ECMWF VALUES FOR TEMPS SATURDAY NIGHT THROUGH SUNDAY NIGHT. TEMPERATURES WILL GRADUALLY WARM MONDAY AND TUESDAY AS THE UPPER LEVEL TROF RELAXES...BUT INDIVIDUAL SHORT WAVES MOVING THROUGH AN UPPER LEVEL NORTHWEST FLOW COMBINED WITH A WEAK SOUTHEAST FLOW WILL GENERATE AFTERNOON SHOWERS AND STORMS. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 715 PM EDT TUESDAY... SOME STORMS WHICH HAVE DEVELOPED TONIGHT HAVE BEEN AWAY FROM ANY TERMINALS. THEY WILL WEAKEN QUICKLY AFTER SUNSET. MANY AREAS WILL SEE VALLEY AND RIVER FOG DEVELOPING OVERNIGHT...WITH MOST AREAS MVFR FOR VSBYS BY SUNRISE WITH ISOLATED IFR OR LOWER. VLIFR/LIFR CIGS AREA ALSO POSSIBLE WITHIN THE VALLEYS. ANY SUB-VFR CONDITIONS SHOULD IMPROVE TO VFR BY 13-14Z...9-10AM...WEDNESDAY A FRONTAL BOUNDARY WILL HOVER AROUND THE REGION THROUGH THE WEEKEND WITH PERIODIC WAVES OF ENERGY RIDING ALONG IT. LOOK FOR AT LEAST ISOLATED DIURNAL CONVECTION DURING THIS TIME PERIOD...WITH FRIDAY INTO SATURDAY HAVING A BETTER CHANCE OF ORGANIZED CONVECTION AS A LOW DEVELOPS OVER THE MIDWEST AND EJECTS THE FRONT EASTWARD AS A STRONG COLD FRONT. LATE NIGHT/EARLY MORNING MOUNTAIN AND RIVER VALLY FOG IS ALSO EXPECTED MOST NIGHTS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/WP SHORT TERM...PH LONG TERM...PH AVIATION...DS/KM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
719 PM EDT TUE AUG 7 2012 .SYNOPSIS... A PERIOD OF UNSETTLED WEATHER WILL CONTINUE THIS WEEK AS A FRONTAL BOUNDARY OSCILLATES ACROSS THE MID ATLANTIC REGION. A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION ON FRIDAY...BRINGING A GENEROUS COVERAGE OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND DRIER WEATHER IS EXPECTED BY THE START OF THE NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 233 PM EDT TUESDAY... A FRONTAL BOUNDARY WAS SLOWLY HEADING SOUTH THROUGH THE REGION. THE FRONT...ALONG WITH DAYTIME HEATING...IS HELPING ISOLATED SHOWERS TO DEVELOP THIS AFTERNOON NEAR THE CREST OF THE BLUE RIDGE FROM ROUGHLY FLOYD VA...SOUTHWEST INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA. OTHER ISOLATED SHOWERS WERE OVER PARTS OF THE MOUNTAIN EMPIRE REGION OF SOUTHWEST VIRGINIA AND SOUTHSIDE VIRGINIA. THESE ARE EXPECTED TO CONTINUE THROUGH THE AFTERNOON...AND PERHAPS INCREASE IN COVERAGE AND GAIN A FEW STRIKES OF LIGHTNING. THIS FRONT WILL CONTINUE TO SLOWLY HEAD SOUTH THROUGH THE NIGHT...SO THAT HIGH PRESSURE WILL BE NOSING SOUTH INTO THE REGION BY WEDNESDAY. THIS HIGH WILL BRING A TREND TOWARDS DECREASING CLOUDS OVERNIGHT INTO EARLY WEDNESDAY MORNING. LIGHT WINDS...AND LINGERING BOUNDARY LAYER MOISTURE BELOW THE NOCTURNAL INVERSION WILL HELP GENERATE AREAS OF FOG TONIGHT ACROSS A GENEROUS PORTION OF THE AREA. WHILE THERE IS BOUND TO BE SOME DENSE FOG...CONFIDENCE IN IT BEING WIDESPREAD ARE NOT HIGH AT THIS TIME. WILL HIGHLIGHT THE POTENTIAL FOR SOME DENSE FOG TONIGHT IN ALL BUT THE BLUEFIELD TO TAZEWELL AREA. LOW TEMPERATURES TONIGHT WILL AVERAGE THREE TO FIVE DEGREES COOLER THAN READINGS EXPERIENCED THIS MORNING. ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR AS PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH. HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED SHOWERS SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING FARTHER TO OUR SOUTH...MORE SUNSHINE SHOULD YIELD HIGH TEMPERATURES ON WEDNESDAY ABOUT THREE TO FIVE DEGREES WARMER THAN TODAY. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 242 PM EDT TUESDAY... CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE SHORT TERM PERIOD AS AN UPPER LEVEL TROF AMPLIFIES OVER THE GREAT LAKES AND INTO THE OHIO VALLEY BY FRIDAY. IN ADVANCE OF THIS SYSTEM...TEMPERATURES SHOULD WARM TOWARD THE WARMER NAM MOS VALUES ON THURSDAY AS THE LOW LEVEL THERMAL RIDGE NOSES INTO OUR AREA. BEST CHANCES FOR THUNDERSTORMS ON THURSDAY WILL BE IN THE WEST AS A LEAD SHORT WAVE (OVERDONE BY THE GFS) APPROACHES OUR AREA AND INTERACTS WITH A MODERATELY UNSTABLE AIRMASS. KEPT POPS IN THE EASTERN PORTION OF THE FORECAST AREA ON THURSDAY AS WEAK LOW LEVEL CONVERGENCE ALONG A LEE-SIDE TROF SHOULD GENERATE SCATTERED CONVECTION. THIS CONVECTION MAY LINGER A FEW HOURS BEYOND SUNDOWN THURSDAY NIGHT WITH SUPPORT FROM THE WEAK UPPER LEVEL WAVE MOVING THROUGH. THE TREND OF THE MODELS FOR FRIDAY`S SYSTEM HAS BEEN TO SLOW ITS EASTWARD PROGRESS SLIGHTLY. BY 00Z (8 PM EDT) SATURDAY...MOST MODELS SHOW THE COLD FRONT STILL WEST OF OUR FORECAST AREA. THE POTENTIAL EXISTS FOR STRONG TO SEVERE STORMS TO ERUPT IN ADVANCE OF THIS SYSTEM AS THE AREA COMES UNDER THE INFLUENCE OF THE RR QUAD OF AN UPPER LEVEL JET ROTATING AROUND THE EASTERN SIDE OF THE APPROACHING SHORT WAVE TROF. THE BIGGEST QUESTION CONCERNING THE POTENTIAL FOR SEVERE WEATHER WILL BE THE INSTABILITY. CLOUDS ON FRIDAY SHOULD KEEP HIGH TEMPS BELOW THURSDAY`S EXPECTED HIGHS AND MAY KEEP INSTABILITY DOWN. THE GFS CRAVEN SIG SVR PARAMETER FORECAST KEEPS THE HIGHEST POTENTIAL FOR SEVERE WEATHER TO OUR SOUTHEAST...WHERE INSTABILITY IS FORECAST TO BE HIGHER. CONSIDERING THE STRENGTH OF THIS UPPER LEVEL SYSTEM...WILL KEEP MENTION OF SVR WX IN THE HWO...ALONG WITH THE THREAT FOR HEAVY RAIN WITH PWATS EXPECTED TO EXCEED 2 INCHES IN THE EAST. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 242 PM EDT TUESDAY... THE LONG RANGE MODELS ARE IN GOOD AGREEMENT THAT THE EASTERN U.S. REMAINS UNDER THE INFLUENCE OF AN UPPER TROF THAT DE-AMPLIFIES WITH TIME. AHEAD OF THE UPPER TROF...A STRONG COLD FRONT WILL SWEEP THROUGH FRIDAY NIGHT. THE 00Z ECMWF HOLDS MORE UPPER LEVEL ENERGY ON THE WEST SIDE OF THE UPPER TROF AND KEEPS PRECIP LINGERING IN THE FAR EASTERN PORTION OF OUR FORECAST AREA ON SATURDAY. SO WE HAVE DELAYED THE ENDING TIME OF THE PRECIP UNTIL MIDDAY SATURDAY. OTHERWISE...UPSLOPE RAIN SHOWERS CAN BE EXPECTED UNDER THE TROF AXIS AND LOW LEVEL NORTHWEST WINDS. DRIER...COOLER AND LESS HUMID AIR WILL INVADE THE REGION LATE SATURDAY INTO SUNDAY. THE GEFS SHOWS 850MB TEMPS BY 18Z SATURDAY WILL BE 1-2 STANDARD DEVIATIONS BELOW NORMAL. SO...LEANED TOWARD THE COOLER ECMWF VALUES FOR TEMPS SATURDAY NIGHT THROUGH SUNDAY NIGHT. TEMPERATURES WILL GRADUALLY WARM MONDAY AND TUESDAY AS THE UPPER LEVEL TROF RELAXES...BUT INDIVIDUAL SHORT WAVES MOVING THROUGH AN UPPER LEVEL NORTHWEST FLOW COMBINED WITH A WEAK SOUTHEAST FLOW WILL GENERATE AFTERNOON SHOWERS AND STORMS. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... AS OF 132 PM EDT TUESDAY... SOME STORMS WHICH HAVE DEVELOPED TONIGHT HAVE BEEN AWAY FROM ANY TERMINALS. THEY WILL WEAKEN QUICKLY AFTER SUNSET. MANY AREAS WILL SEE VALLEY AND RIVER FOG DEVELOPING OVERNIGHT...WITH MOST AREAS MVFR FOR VSBYS BY SUNRISE WITH ISOLATED IFR OR LOWER. VLIFR/LIFR CIGS AREA ALSO POSSIBLE WITHIN THE VALLEYS. ANY SUB-VFR CONDITIONS SHOULD IMPROVE TO VFR BY 13-14Z...9-10AM...WEDNESDAY A FRONTAL BOUNDARY WILL HOVER AROUND THE REGION THROUGH THE WEEKEND WITH PERIODIC WAVES OF ENERGY RIDING ALONG IT. LOOK FOR AT LEAST ISOLATED DIURNAL CONVECTION DURING THIS TIME PERIOD...WITH FRIDAY INTO SATURDAY HAVING A BETTER CHANCE OF ORGANIZED CONVECTION AS A LOW DEVELOPS OVER THE MIDWEST AND EJECTS THE FRONT EASTWARD AS A STRONG COLD FRONT. LATE NIGHT/EARLY MORNING MOUNTAIN AND RIVER VALLY FOG IS ALSO EXPECTED MOST NIGHTS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS SHORT TERM...PH LONG TERM...PH AVIATION...DS/KM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 PM CDT MON AUG 6 2012 .SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT 305 PM CDT MON AUG 6 2012 MAIN FORECAST CHALLENGES ARE ON RAIN CHANCES TONIGHT AND EARLY TUESDAY AND AGAIN WEDNESDAY THROUGH THURSDAY. 18Z SURFACE ANALYSIS SHOWS HIGH PRESSURE STRETCHING FROM NORTHERN ILLINOIS INTO SOUTHERN LOWER MICHIGAN. VISIBLE SATELLITE IMAGERY SHOWING CLEAR SKIES ACROSS THE ENTIRE UPPER MIDWEST AND GREAT LAKES REGION. 06.12Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE NEAR TERM...SHORTWAVE TROUGH WILL ROTATE ACROSS LAKE SUPERIOR TONIGHT...PUSHING A WEAK SURFACE TROUGH THROUGH THE FORECAST AREA. MODELS SHOWING LOW LEVELS TO REMAIN RELATIVELY DRY WITH MOISTURE AT OR ABOVE 800MB. MID LEVEL INSTABILITIES IN THE ORDER OF 400 J/KG TO 800 J/KG ARE PROGGED OVER THE AREA AS THE TROUGH DROPS SOUTHWARD OVERNIGHT. 06.12Z NAM GOING DRY TONIGHT...WHILE GFS SHOWS SOME LIGHT QPF. VARIOUS MESO MODELS ALSO DIFFERING...WITH THE 06.14Z HRRR DEVELOPING CONVECTION IN THE HIGHER CAPE AREA OVER CENTRAL SOUTHERN MINNESOTA AND THE 06.12 NMM EAST KEEPING THINGS DRY UNTIL AFTER 09Z. WITH THESE DIFFERENCES WILL CONTINUE THE LOWER END PROBABILITIES FOR TONIGHT AND JUST ACROSS THE SOUTH ON TUESDAY. HIGH PRESSURE THEN BUILDS ACROSS THE AREA TUESDAY NIGHT...BUT THIS WILL BE QUITE TRANSITORY AS NEXT SHORTWAVE IN THE NORTHWEST FLOW DROPS QUICKLY THROUGH THE DAKOTAS AND THIS WILL SPREAD SOME MID AND HIGH LEVEL CLOUDS INTO THE AREA AFTER MIDNIGHT...BUT THE AREA WILL REMAIN DRY. MODELS HAVE BEEN PRETTY CONSISTENT IN THE WEDNESDAY THROUGH THURSDAY TIME FRAME. MID LEVEL TROUGH DIGS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY REGION...WITH AN INCREASE IN MOISTURE TRANSPORT INTO THE AREA. ISENTROPIC LIFT INCREASES LATE WEDNESDAY...WITH THE MAIN RAIN CHANCES WEDNESDAY NIGHT. GFS INDICATING BETTER INSTABILITIES TO REMAIN TO THE SOUTH OF THE AREA. LIFT CONTINUES FOR MUCH OF THURSDAY AS TROUGH AXIS REMAINS JUST WEST OF THE AREA. SYSTEM THEN BEGINS TO PULL AWAY THURSDAY NIGHT AS HIGH PRESSURE BEGINS TO BUILD SOUTHWARD. .LONG TERM...FRIDAY THROUGH MONDAY 305 PM CDT MON AUG 6 2012 NORTH TO NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD. EXITING TROUGH WILL CONTINUE TO DEEPEN OVER THE GREAT LAKES AND MOVE EASTWARD FRIDAY INTO SATURDAY...WHILE HIGH PRESSURE DOMINATES THE WEATHER FOR THE LOCAL AREA. THE HIGH WILL SLIDE OFF TO THE EAST SATURDAY NIGHT...ALLOWING FOR MOISTURE RETURN ON ITS BACKSIDE AHEAD OF THE NEXT SHORTWAVE/SURFACE TROUGH. GFS MUCH DEEPER WITH THIS FEATURE...WHILE 06.12Z ECMWF IS MUCH WEAKER AND EVEN DRY IN ITS QPF FIELDS. SYSTEM THEM DROPS SOUTH WITH QUIET WEATHER EXPECTED INTO MONDAY. WITH THE NORTHWEST FLOW...TEMPERATURES WILL BE RATHER PLEASANT AVERAGING AT OR BELOW NORMAL. && .AVIATION... 600 PM CDT MON AUG 6 2012 THERE APPEARS TO BE TWO FOCUSES FOR AN ISOLATED SHRA/TS TONIGHT. FIRST IS NORTH WITH A SFC FRONT/TROUGH MOVING SOUTHWARD ACROSS THE REGION. SOME FRONTOGENETIC FORCING AND WEAK MLCAPE AROUND THE BOUNDARY. DECENT PUSH OF 850 MB MOISTURE VIA THE RAP. THE HRRR AND NAM12 POP SOME CONVECTION ALONG THE BOUNDARY...BUT ITS MOSTLY CONFINED ACROSS NORTHERN WI TONIGHT. THE OTHER FOCUS IS ANOTHER SFC BOUNDARY WITH ACCOMPANYING LOW AROUND THE IA/MN BORDER. SOME 900-700 MB FRONTOGENETIC FORCING INDICATED IN THE RAP...ALONG WITH MLCAPES UPWARDS OF 3000 J/KG THIS EVENING. THE HRRR AND NAM12 ALSO DEVELOP SOME ISOLATED SHRA/TS DUE TO THIS FORCING...AND THIS ACTIVITY WOULD HAVE THE BETTER CHANCE OF IMPACTING KRST/KLSE. IT SHOULD BE NOTED THAT MOST OF THE SATURATION INDICATED FOR THE FORCING TO WORK ON IS MOSTLY MID TO UPPER LEVEL. BASES ON ANY SHRA/TS COULD BE 8-10 KFT. RELATIVELY DRY NEAR SFC LAYER COULD ENHANCE ANY GUSTINESS AROUND A STORM...OTHERWISE IMPACTS VIA CIGS/VSBY LOOK MINIMAL AT THIS TIME. CONFIDENCE NOT HIGH...BUT ENOUGH SUPPORT FROM THE VARIOUS MESO MODELS TO CONTINUE THE VCSH MENTION AT KRST/KLSE FOR A PERIOD TONIGHT. FRONT TO THE NORTH WILL SLIDE THROUGH TUE MORNING...SWITCHING THE WINDS TO THE NORTHWEST. HIGH PRESSURE WILL FOLLOW IN ITS WAKE...WITH QUIET VFR CONDITIONS THEN INTO TUE NIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... 305 PM CDT MON AUG 6 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...JLR LONG TERM....JLR AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
321 PM CDT MON AUG 6 2012 .SHORT TERM... TONIGHT...FORECAST CONFIDENCE MEDIUM INFLUENCE OF SURFACE HIGH WANES WITH SURFACE TROUGH APPROACHING FROM NRN MN. CLEAR FOR MUCH OF THE NIGHT. 4 KM WRF MODEL NUDGES PRECIP FROM SE MN INTO EXTREME SW WI LATE TONIGHT AS DOES GFS...THOUGH FOCUSING BOUNDARY STILL BACK TO THE NORTHWEST. LOSS OF HEATING WILL BE A FACTOR IN SUSTAINING ANYTHING INTO OUR AREA. HOWEVER UPPER FLOW UPPER FLOW IS SWIFT AND CYCLONIC FROM THE NORTHWEST WITH RUC SHOWING A 15 UNIT VORT MAX/JET STREAK IN CENTRAL MN. BUT AGAIN AIRMASS IS SO VERY DRY AND ONLY SLIGHTLY UNSTABLE ALOFT...SO WILL GO WITH A DRY FORECAST FOR NOW. TUESDAY...FORECAST CONFIDENCE MEDIUM NW UPPER FLOW CONTINUES WITH ONLY WEAK LOBES NOTED. WEAK FRONTOGENETICAL FORCING NOTED WITHIN THE LAYER WHERE LIMITED MOISTURE AND BASE OF ELEVATED CAPE RESIDE. REALLY CANNOT COMPLETELY RULE OUT ISOLATED DEVELOPMENT...SO VERY SMALL CHANCES SEEM OK. 925 TEMPS 24-26C SO TOASTY TOMORROW WITH AMPLE SUNSHINE. TUESDAY NIGHT THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM A WEAK HIGH PRESSURE RIDGE WILL BUILD INTO SRN WI FROM THE NORTH FOR TUE NT AND WED. HOWEVER CLOUDS WILL INCREASE WED AFTERNOON AS A SHORTWAVE TROUGH WITHIN NW FLOW ALOFT MOVES TO NRN IA BY 00Z THU WITH A DEVELOPING WARM FRONT ALONG THE MN/IA BORDER. THE SHORTWAVE TROUGH WILL THEN PASS INTO IL WED NT WITH A WAVE OF LOW PRESSURE TO MOVE FROM MN TO ERN IA IN RESPONSE TO A MUCH STRONGER UPPER TROUGH DIGGING SWD FROM CANADA. THE WAVE OF LOW PRESSURE WILL THEN LIKELY TRACK ACROSS IL ON THU WITH THE UPPER LOW MOVING SEWD ACROSS WI. WITH THE ORGANIZED LOW PRESSURE AREA THERE WILL BE DECENT SFC-850 MB FRONTOGENESIS WITH PWS INCREASING TO 1.3-1.5 INCHES. MODELS DO DIFFER ON TIMING...STRENGTH AND PLACEMENT OF THE AFOREMENTIONED FEATURES BUT STILL ENOUGH CONFIDENCE FOR HIGH CHANCE TO LIKELY POPS FOR WED NT AND THU WITH LINGERING POPS THU NT. .LONG TERM... FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM THE UPPER LOW WILL MOVE AWAY FOR FRIDAY WITH NLY WINDS WEAKENING. A WEAK NW FLOW ALOFT WILL THEN PREVAIL THROUGH THE PERIOD WITH SFC HIGH PRESSURE AND DRY CONDITIONS OVER THE REGION. TEMPS WILL BE NEAR NORMAL. && .AVIATION/00Z TAFS/...VFR THROUGH THE FORECAST PERIOD. SOME MID CLOUDS LATE TONIGHT/TUESDAY MORNING AS SURFACE TROUGH APPROACHES. WILL LEAVE MENTION OR SHRA/TSRA DUE TO LOW CONFIDENCE OF OCCURRENCE AND LIKELY ISOLATED AREAL COVERAGE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ TONIGHT/TUESDAY AND AVIATION/MARINE...COLLAR TUESDAY NIGHT THROUGH MONDAY...GEHRING
AREA FORECAST DISCUSSION
NWS CARIBOU ME
102 AM EDT WED AUG 8 2012 .SYNOPSIS... HIGH PRESSURE WILL MOVE EAST OF THE AREA TONIGHT. A WEAK FRONTAL BOUNDARY WILL APPROACH FROM THE NORTHWEST ON WEDNESDAY AND STALL OVER THE AREA THROUGH LATE WEEK. && .NEAR TERM /THROUGH TODAY/... 1 AM UPDATE...ADJUSTED SKY GRID TO ACCOUNT FOR LATEST SATELLITE TREND. 10 PM UPDATE...TWEAKED TEMPERATURES TO MATCH THE LATEST TRENDS. RADAR SHOWING SOME SHOWERS MOVE NE ACROSS QUEBEC. RUC HAS SOME OF THESE SHOWERS SKIRTING NORTHERN AND NWRN AREAS OVERNIGHT INTO EARLY MORNING. LATEST FCST HAS THIS HANDLED WELL. PREVIOUS DISCUSSION... TONIGHT WILL REMAIN MOSTLY CLEAR IN SOUTHERN AND SOUTHEAST AREAS. SOME CLOUDS WILL GRADUALLY INCREASE ACROSS THE NORTHWEST AS A WEAK COLD FRONT SLOWLY APPROACHES FROM QUEBEC. SOME SHOWERS MAY AFFECT FAR NORTHWESTERN AREAS LATE TONIGHT OR WEDNESDAY MORNING. AS THE FRONT NEARS WEDNESDAY AFTERNOON SOME THUNDERSTORMS WILL BE POSSIBLE. THE BEST CHANCES FOR THUNDERSTORMS WEDNESDAY AFTERNOON WILL BE OVER FAR NORTHWESTERN AREAS NEAR THE FRONTAL BOUNDARY WHERE SOME CONVERGENCE WILL OFFER SUPPORT FOR THUNDERSTORM ACTIVITY. BOTH THE NAM AND GFS ARE FORECASTING CAPES NEAR 300 J/KG. CAPES AROUND 300 CAN SUPPORT SOME CONVECTION BUT ARE LIKELY TOO WEAK TO SUPPORT ANYTHING SEVERE. TEMPS TONIGHT WILL RANGE FROM THE MID 50S EAST WHERE SKIES WILL BE MOSTLY CLEAR TO NEAR 60 NORTHWEST WHERE SOME CLOUD COVER WILL LIMIT COOLING. TEMPS ON WEDNESDAY WILL BE IN THE LOW 80S IN MOST AREAS. && .SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/... A WEAK AREA OF LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL MOVE ACROSS THE REGION WEDNESDAY NIGHT BRINGING SOME SHOWERS AND THUNDERSTORMS MAINLY TO THE NORTHERN HALF OF THE REGION. AS ABUNDANT LOW LEVEL MOISTURE IS DRAWN NORTH ON SOUTHERLY WINDS AHEAD OF THE FRONT THIS WILL RESULT IN FOG DEVELOPMENT OVER DOWNEAST AREAS. THE FRONT STALLS ACROSS THE REGION ON THURSDAY RESULTING IN CONSIDERABLE CLOUDINESS WITH ADDITIONAL SHOWERS AND THUNDERSTORMS. THE NAM DEPICTS CAPE VALUES EXCEEDING 1000 J/KG BY THE AFTERNOON WITH 0-6 KM SHEAR VALUES EXCEEDING 40 KNOTS. HOWEVER CLOUD COVER WILL ACT TO LIMIT THE POTENTIAL FOR SEVERE STORMS AS IT LIMITS HEATING. HAVE GONE WITH UPPER 70S NORTH AND LOW 80S SOUTH. ANY CONVECTION WILL WIND DOWN THURSDAY EVENING. HAVE MAINTAINED SHOWERS THROUGH THE NIGHT WITH THE FRONT STALLING DOWN EAST. LOWS WILL BE IN THE LOW TO MID 60S IN THE RATHER HUMID AIR MASS. MODELS BEGIN TO DIVERGE HEADING INTO FRIDAY. LOW PRESSURE LOOKS TO DEVELOP FRIDAY IN THE OHIO VALLEY WITH A SHIELD OF RAIN EXTENDING NORTH AND EAST FROM THIS SYSTEM ALONG THE FRONT. THE NAM AND THE ECMWF ARE FAIRLY AGGRESSIVE BRINGING STEADIER AND HEAVIER PRECIPITATION INTO THE REGION DURING THE DAY COMPARED TO THE GFS AND ESPECIALLY THE GEM GLOBAL. AT THIS POINT OPTED TO KEEP IN CHANCE POPS OVER MOST OF THE CWA WITH A SMALL AREA OF LIKELY POPS NUDGING INTO AREAS JUST WEST OF BANGOR BY LATE DAY. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... LOW PRESSURE WILL INTENSIFY ACROSS THE MID ATLANTIC REGION FRIDAY NIGHT WITH HIGH PRESSURE LOCATED NORTH OF THE REGION. THE LOW THEN SLOWLY LIFTS NORTH SATURDAY...WHILE HIGH PRESSURE MOVES NORTHEAST. UNCERTAINTY STILL EXISTS REGARDING HOW QUICKLY RAIN IS ABLE TO EXPAND ACROSS THE FORECAST AREA FRIDAY NIGHT THROUGH SATURDAY. HIGH PRESSURE TO THE NORTHEAST SHOULD HELP SUPPLY LOW LEVEL DRY AIR WHICH COULD SLOW THE EXPANSION OF RAIN ACROSS THE REGION. EXPECT THE BEST CHANCES OF RAIN WILL REMAIN ACROSS SOUTHWEST PORTIONS OF THE FORECAST AREA FRIDAY NIGHT THROUGH EARLY SATURDAY. THE RAIN SHOULD THEN EXPAND ACROSS THE REGION THROUGH THE REMAINDER OF SATURDAY. THE LOW WILL LIFT NORTH SATURDAY NIGHT THROUGH SUNDAY...DRAWING AN OCCLUDED FRONT ACROSS THE FORECAST AREA. RAIN IS EXPECTED ACROSS THE ENTIRE REGION SATURDAY NIGHT THROUGH EARLY SUNDAY IN ADVANCE OF THE OCCLUSION...WITH PRECIPITATION THEN TAPERING TO SHOWERS IN THE WAKE OF THE OCCLUSION LATER SUNDAY. THE LOW WILL LIFT NORTH OF THE REGION MONDAY...WITH A SLIGHT CHANCE OF SHOWERS LINGERING ACROSS NORTHERN AREAS. A COLD FRONT WILL APPROACH LATER TUESDAY BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO MOSTLY NORTHERN AREAS DURING THE AFTERNOON. TEMPERATURES SHOULD BE AT SLIGHTLY BELOW NORMAL LEVELS SATURDAY/SUNDAY...WITH NEAR NORMAL LEVEL TEMPERATURES EXPECTED MONDAY/TUESDAY. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: SOME PATCHY FOG MAY AFFECT DOWNEAST AREAS LATE TONIGHT. OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE AREA THROUGH WEDNESDAY. SHORT TERM: IFR LIKELY TO DEVELOP WEDNESDAY NIGHT SOUTH OF HUL AND MLT WITH STRATUS AND FOG. THIS WILL CONTINUE INTO EARLY THURSDAY MORNING. VFR FOR LATER THURSDAY MORNING INTO THE EVENING OUTSIDE OF THUNDERSTORMS. FOG AND STRATUS REAPPEARS THURSDAY NIGHT FOR ALL TERMINALS AND MAY BE VERY SLOW TO LIFT FRIDAY MORNING...ESPECIALLY DOWNEAST. LOW PRESSURE ARRIVES BY LATE DAY TO PROVIDE PREDOMINANT IFR FOR ALL SITES DUE TO LOW CLOUDS AND RAIN. CONDITIONS FRIDAY NIGHT THROUGH SATURDAY WILL BE DEPENDENT ON HOW QUICKLY RAIN IS ABLE TO EXPAND ACROSS THE REGION. HOWEVER...MVFR/IFR CONDITIONS ARE POSSIBLE FRIDAY NIGHT INTO SATURDAY WITH A MORE RAPID EXPANSION OF THE RAIN. MVFR/IFR CONDITIONS ARE THEN EXPECTED SATURDAY NIGHT INTO SUNDAY. && .MARINE... NEAR TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA TONIGHT AND WEDNESDAY. SHORT TERM: FOG IS EXPECTED WEDNESDAY NIGHT AND WILL REMAIN A FACTOR IN THE FORECAST THROUGH FRIDAY. CONDITIONS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS WEDNESDAY NIGHT THROUGH FRIDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HEWITT/RUNYAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
339 AM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW PRESSURE WILL MOVE UP THE OHIO VALLEY TONIGHT AND FRIDAY. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS WILL BE A DEGREE OR TWO COOLER THAN TUESDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE. EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE BELOW NORMAL FOR A CHANGE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... A WEAK COLD FRONT N OF LAKE ERI ACROSS SRN MI WILL CONTINUE TO SLOWLY MOVE SOUTH ACROSS SITES THROUGH TODAY. RADAR SHOWING ONE ISOL SHRA MOVING INTO NW OH SO WILL HAVE TO WATCH TOL...BUT NOT THINKING MUCH FOR IMPACT. OTHERWISE EXPECTING SOME CLOUDS TO DEVELOP LATER THIS MORNING AND AFTN ACROSS NRN OH AHEAD OF THE FRONT. THERE MAY BE SOME ISOL SHRA WITH IT BUT NOT CONFIDENT ON OCCURRENCE OR TIMING AT ANY PARTICULAR SITES. AT THIS TIME WOULD THINK MFD-CAK-YNG WOULD HAVE BEST CHANCE FOR SHRA THIS AFTN. SOUTH WINDS WILL GRADUALLY TURN NORTH AFTER FROPA THROUGH TODAY. .OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES. && .MARINE... A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY. HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND CONTINUING THROUGH AT LEAST SATURDAY MORNING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...ABE AVIATION...ABE MARINE...ABE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
157 AM EDT WED AUG 8 2012 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE OHIO VALLEY WILL CONTINUE THE DRY WEATHER OVERNIGHT TONIGHT. A WEAK COLD FRONT UNDERNEATH A MID LEVEL DISTURBANCE WILL SLIP DOWN FROM THE NORTH ON WEDNESDAY AND REMAIN NEAR THE OHIO RIVER THROUGH THURSDAY. A STRONG UPPER LOW WILL MOVE INTO THE OHIO VALLEY REGION THURSDAY NIGHT AND FRIDAY INCREASING THE CHANCE FOR PRECIPITATION. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... HIGH PRESSURE WILL BRING MOSTLY CLEAR SKIES TO OUR AREA TO START THE OVERNIGHT PERIOD. A WEAK DISTURBANCE APPROACHING THE NORTHERN ZONES LATE TONIGHT MAY BRING SOME SCATTERED LOW AND MID LEVEL CLOUDS ACROSS THOSE ZONES. THE HRRR AND RAP TRY TO PRODUCE ISOLATED SHOWERS WITH THIS FEATURE AROUND DAYBREAK. HAVE HELD OFF ON ANY MENTIONABLE CHANCES FOR PRECIP AS THE NORTHERN ZONES HAVE DEWPOINTS GENERALLY IN THE UPPER 50S...SO ANYTHING THAT DOES DEVELOP WILL PROBABLY NOT HAVE PRECIP REACH THE SURFACE. TEMPERATURES HAVE BEEN SLOW TO DROP OFF ACROSS MOST OF THE SOUTHWEST...AND DAYTON...WILMINGTON...AND COLUMBUS METRO AREA. HAVE THEREFORE TWEAKED UP OVERNIGHT LOWS IN THESE AREAS. ALSO OF NOTE IS THE UPPER 60S DEWPOINTS THAT HAVE FOUND THEIR WAY INTO OUR AREA BETWEEN THE EASTERN CINCINNATI METRO AREA AND PORTSMOUTH. THIS COULD BE A PRECURSOR TO FOG DEVELOPMENT LATER TONIGHT ESPECIALLY ACROSS THE RIVER VALLEYS. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... A WEAK COLD FRONT WILL DROP SOUTH INTO THE REGION ON WEDNESDAY. THERE IS LITTLE SUPPORT FOR CONVECTION BUT IT WILL BRING A SLIGHT CHANCE TO PARTS OF THE FA. THE FRONT WILL BECOME NEARLY STATIONARY NEAR THE OHIO RIVER. TEMPERATURES ON WEDNESDAY WILL WARM UP COMPARED TO TODAY AS WWA TAKES OVER AHEAD OF THE NEXT STRONG UPPER LEVEL TROF. EXPECT TEMPERATURES IN THE MID 90S SOUTH TO UPPER 80S EXTREME NORTH. BOTH ECMWF AND GFS HAVE A LOW DEVELOPING SW ALONG THE FRONT AND MOVING INTO THE REGION THURSDAY/THURSDAY NIGHT. THE MODELS DIFFER THOUGH ON STRENGTH AND EXACT PLACEMENT OF THE LOW WHICH WILL ULTIMATELY EFFECT PRECIPITATION LOCATION AND AMOUNTS. HAVE CHANCE POPS THURSDAY INCREASING THEM TO LIKELY THURSDAY NIGHT AS DEEPER UPPER LEVEL TROF APPROACHES FORECAST AREA. THE HIGH TEMPERATURES WILL BE A FEW DEGREES COOLER ON THURSDAY WITH AN INCREASE IN CLOUDS. THE LOW TEMPERATURES WILL BE IN THE MID TO UPPER 60S WEDNESDAY NIGHT AND THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS CONTINUE TO HAVE DIFFICULTY RESOLVING THE TIMING AND STRENGTH OF DIGGING S/WV TROF INTO THE GREAT LAKES ON FRIDAY AND HOW LONG IT LINGERS INTO THE FIRST PART OF THE UPCOMING WEEKEND. ATTM...HAVE USED A BLEND OF THE 00Z ECMWF AND NCEP HPC GUIDANCE IN WHICH SFC LOW PRESSURE IS MORE SUBDUED AND RIPPLES ALONG OLD FRONTAL BOUNDARY ALONG THE OHIO RIVER ON FRIDAY. THIS SOLUTION CALLS FOR LIKELY POPS AND TEMPERATURES ON THE COOLER SIDE DUE TO CLOUDS...PCPN...AND SOME LOCATIONS UNDER THE INFLUENCE OF A NORTHERLY FLOW ON THE BACK SIDE OF THE LOW. HOWEVER...IT MUST BE NOTED THAT THE NEW 12Z ECMWF IS GIVING INDICATIONS SIMILAR TO THE 12Z GFS THAT PERHAPS THE SFC LOW WILL DEEPEN AND TRACK FARTHER NW ALONG I-71. THIS LATTER SOLUTION WOULD BRING A SHARPER TEMPERATURE GRADIENT TO THE REGION AND COULD POSE A SMALL RISK OF SEVERE WEATHER TO AREAS LOCATED SE OF THE LOW TRACK. HOPEFULLY...LATER MODEL RUNS WILL RESOLVE THIS DILEMMA...BUT MODELS TEND TO HAVE DIFFICULTY IN DIGGING AND DEVELOPING CLOSED MID LEVEL CIRCULATIONS. FOR FRIDAY NIGHT NIGHT INTO SATURDAY NIGHT...AGAIN...A QUICKER UPR LVL LOW MOTION TO THE NE WAS USED BUT MAY END UP BEING SLOWER THAN CURRENTLY FORECAST DUE TO RECENT MODEL GUIDANCE. HAVE A CHANCE OF SHOWERS DIMINISHING WEST TO EAST THROUGH THIS PERIOD ALONG WITH GRADUAL CLEARING SATURDAY INTO SATURDAY NIGHT. TEMPERATURES ON SATURDAY WILL BE CLOUD DEPENDENT AND HAVE GONE WITH HIGHS IN THE MID TO UPPER 70S. LOWS SATURDAY NIGHT WILL BE COOL AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. FOR THE REMAINDER OF THE EXTENDED...SUNDAY THROUGH TUESDAY...THE GREAT LAKES AND OHIO VALLEY AREA WILL BE UNDER A NORTHWEST FLOW PATTERN ALOFT. THERE ARE INDICATIONS THAT A FEW WEAK DISTURBANCES WILL RIPPLE SE WITHIN THIS FLOW...BRINGING A SMALL THREAT FOR PCPN. GIVEN THAT THEY APPEAR WEAK ATTM AND TIMING IS DIFFICULT AT BEST AT THIS JUNCTURE...HAVE MAINTAINED A DRY FORECAST ALONG WITH MODIFYING TEMPERATURES AS HEIGHTS AND TEMPERATURES ALOFT RISE THROUGH THE PERIOD. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... SEEING SOME 8K FT AC DEVELOPING ACROSS THE MIAMI AND WHITEWATER VALLEYS. THIS IS EXPECTED TO GRADUALLY WORK EWD OVERNIGHT. KEPT THESE CLDS SCT FOR THE OVERNIGHT. MVFR AND POSSIBLE SOME IFR FOG ARE POSSIBLE UNTIL 12Z AT ILN AND LUK. WEAK CDFNT WORKS INTO THE FA TODAY. MOISTURE IS RATHER LIMITED...SO ONLY EXPECT CLDS DEVELOPMENT WITH THE FNTL LIFT. MODELS ARE SUGGESTING THAT THE BEST CLDS COVER WILL BE DURING THE LATE AFTN ALONG FRONT WHEN IT REACH AN ARC FROM CMH-PMH-CVG. WENT A WITH A BROKEN AC DECK AT CVG/LUK...BUT LEFT THE CLDS SCT AT THE OTHER TAFS. UPPER LEVEL MOISTURE WILL BEGIN TO INCREASE AFT 00Z AHEAD OF A STRONGER SYSTEM THAT IS DIGGING INTO THE MS VALLEY. .OUTLOOK...THUNDERSTORMS ARE POSSIBLE ON THURSDAY AND FRIDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...PARKER NEAR TERM...LATTO SHORT TERM...PARKER LONG TERM...HICKMAN AVIATION...SITES
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
126 AM EDT WED AUG 8 2012 .SYNOPSIS... A PERIOD OF UNSETTLED WEATHER WILL CONTINUE THIS WEEK AS A FRONTAL BOUNDARY OSCILLATES ACROSS THE MID ATLANTIC REGION. A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION ON FRIDAY...BRINGING A GENEROUS COVERAGE OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND DRIER WEATHER IS EXPECTED BY THE START OF THE NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION. && .NEAR TERM /THROUGH TODAY/... AS OF 1000 PM EDT TUESDAY... THE FRONTAL BOUNDARY PER LATEST MSAS THETA-E/LI GRADIENT LIES FROM ERN KY ENE INTO CENTRAL VA. SHOWERS AND STORMS REMAIN ISOLATED AT BEST WITH BEST CONCENTRATION ACROSS THE NC FOOTHILLS. STORM MOVEMENT HAS BEEN ALL OVER THE PLACE WITH A WEAK FLOW. 00Z SOUNDINGS FROM RNK/GSO SHOW STORM MOTION OF 3 KNOTS OR LESS. LUCKILY HAVE NOT HAD STORMS LINGERING OVER ONE AREA TOO LONG AS THEY TEND TO FADE AFTER AN HOUR. WILL SEE A WEAKENING TREND TO THE ACTIVITY OVERNIGHT AND THINK A SLOW PUSH SOUTHEAST OF THE THETA-E RIDGE WILL KEEP AT LEAST A LOW CHANCE/SLIGHT CHANCE POPS AROUND ALL NIGHT FROM SOUTHSIDE VA/NW NC PIEDMONT WEST TO THE GRAYSON HIGHLANDS/NC MTNS. THE OTHER ISSUE TONIGHT WILL BE FOG AND HOW DENSE WILL IT GET. THE DENSE CANOPY OF CIRROSTRATUS CONTINUES ACROSS THE ENTIRE FORECAST AREA. MODELS SHOW DRIER AIR SNEAKING INTO THE MTNS AFTER 09Z...SO WILL SEE SOME CLEARING. WILL HAVE TO WATCH SFC OBS AND SAT TRENDS FOR POTENTIAL DENSE FOG ADVISORY. SOME SCHOOLS IN NC ARE STARTING IN THE MORNING SO FOG WILL CAUSE A PROBLEM THERE POTENTIALLY. WILL KEEP THE MENTION IN HWO FOR NOW. RAISED TEMPS/DEWPOINTS UP A DEGREE OR TWO OVERNIGHT MAINLY EAST OF THE NEW RIVER VALLEY WHERE THINK MORE CLOUDS ARE GOING TO LINGER THROUGH WED MORNING. PREVIOUS VALID DISCUSSION... ON WEDNESDAY...WE EXPECT ANOTHER DAY COMPARABLE TO TODAY AS FAR AS PRECIPITATION COVERAGE THANKS TO THE FRONT JUST TO OUR SOUTH. HOWEVER...WITH HIGH PRESSURE NOSING SOUTH...CLOUD COVER SHOULD BE LESS...AND A SLIGHTLY STRONGER CAP SHOULD MEAN THE ISOLATED SHOWERS SHOULD BE EVEN MORE ISOLATED. DESPITE THE FRONT BEING FARTHER TO OUR SOUTH...MORE SUNSHINE SHOULD YIELD HIGH TEMPERATURES ON WEDNESDAY ABOUT THREE TO FIVE DEGREES WARMER THAN TODAY. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... AS OF 242 PM EDT TUESDAY... CHANCES FOR THUNDERSTORMS WILL INCREASE THROUGH THE SHORT TERM PERIOD AS AN UPPER LEVEL TROF AMPLIFIES OVER THE GREAT LAKES AND INTO THE OHIO VALLEY BY FRIDAY. IN ADVANCE OF THIS SYSTEM...TEMPERATURES SHOULD WARM TOWARD THE WARMER NAM MOS VALUES ON THURSDAY AS THE LOW LEVEL THERMAL RIDGE NOSES INTO OUR AREA. BEST CHANCES FOR THUNDERSTORMS ON THURSDAY WILL BE IN THE WEST AS A LEAD SHORT WAVE (OVERDONE BY THE GFS) APPROACHES OUR AREA AND INTERACTS WITH A MODERATELY UNSTABLE AIRMASS. KEPT POPS IN THE EASTERN PORTION OF THE FORECAST AREA ON THURSDAY AS WEAK LOW LEVEL CONVERGENCE ALONG A LEE-SIDE TROF SHOULD GENERATE SCATTERED CONVECTION. THIS CONVECTION MAY LINGER A FEW HOURS BEYOND SUNDOWN THURSDAY NIGHT WITH SUPPORT FROM THE WEAK UPPER LEVEL WAVE MOVING THROUGH. THE TREND OF THE MODELS FOR FRIDAY`S SYSTEM HAS BEEN TO SLOW ITS EASTWARD PROGRESS SLIGHTLY. BY 00Z (8 PM EDT) SATURDAY...MOST MODELS SHOW THE COLD FRONT STILL WEST OF OUR FORECAST AREA. THE POTENTIAL EXISTS FOR STRONG TO SEVERE STORMS TO ERUPT IN ADVANCE OF THIS SYSTEM AS THE AREA COMES UNDER THE INFLUENCE OF THE RR QUAD OF AN UPPER LEVEL JET ROTATING AROUND THE EASTERN SIDE OF THE APPROACHING SHORT WAVE TROF. THE BIGGEST QUESTION CONCERNING THE POTENTIAL FOR SEVERE WEATHER WILL BE THE INSTABILITY. CLOUDS ON FRIDAY SHOULD KEEP HIGH TEMPS BELOW THURSDAY`S EXPECTED HIGHS AND MAY KEEP INSTABILITY DOWN. THE GFS CRAVEN SIG SVR PARAMETER FORECAST KEEPS THE HIGHEST POTENTIAL FOR SEVERE WEATHER TO OUR SOUTHEAST...WHERE INSTABILITY IS FORECAST TO BE HIGHER. CONSIDERING THE STRENGTH OF THIS UPPER LEVEL SYSTEM...WILL KEEP MENTION OF SVR WX IN THE HWO...ALONG WITH THE THREAT FOR HEAVY RAIN WITH PWATS EXPECTED TO EXCEED 2 INCHES IN THE EAST. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 242 PM EDT TUESDAY... THE LONG RANGE MODELS ARE IN GOOD AGREEMENT THAT THE EASTERN U.S. REMAINS UNDER THE INFLUENCE OF AN UPPER TROF THAT DE-AMPLIFIES WITH TIME. AHEAD OF THE UPPER TROF...A STRONG COLD FRONT WILL SWEEP THROUGH FRIDAY NIGHT. THE 00Z ECMWF HOLDS MORE UPPER LEVEL ENERGY ON THE WEST SIDE OF THE UPPER TROF AND KEEPS PRECIP LINGERING IN THE FAR EASTERN PORTION OF OUR FORECAST AREA ON SATURDAY. SO WE HAVE DELAYED THE ENDING TIME OF THE PRECIP UNTIL MIDDAY SATURDAY. OTHERWISE...UPSLOPE RAIN SHOWERS CAN BE EXPECTED UNDER THE TROF AXIS AND LOW LEVEL NORTHWEST WINDS. DRIER...COOLER AND LESS HUMID AIR WILL INVADE THE REGION LATE SATURDAY INTO SUNDAY. THE GEFS SHOWS 850MB TEMPS BY 18Z SATURDAY WILL BE 1-2 STANDARD DEVIATIONS BELOW NORMAL. SO...LEANED TOWARD THE COOLER ECMWF VALUES FOR TEMPS SATURDAY NIGHT THROUGH SUNDAY NIGHT. TEMPERATURES WILL GRADUALLY WARM MONDAY AND TUESDAY AS THE UPPER LEVEL TROF RELAXES...BUT INDIVIDUAL SHORT WAVES MOVING THROUGH AN UPPER LEVEL NORTHWEST FLOW COMBINED WITH A WEAK SOUTHEAST FLOW WILL GENERATE AFTERNOON SHOWERS AND STORMS. && .AVIATION /05Z WEDNESDAY THROUGH SUNDAY/... AS OF 100 AM EDT WEDNESDAY... EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET PERSISTS ACROSS THE REGION TONIGHT WITH SOME LOWER STRATO-CU CIGS ALONG THE WESTERN SLOPES ON THE EDGE OF THE CLOUD SHIELD. MAY SEE A FEW ADDED SHRA DEVELOP OVER THE WEST THRU DAWN OTRW THE MAIN CONCERN WITH FOG COVERAGE GIVEN LIMITED COOLING DUE TO CLOUD COVER. THINK ONCE THIS BACKEDGE CLEARS SE WVA WILL SEE KBLF/KLWB DROP TO MVFR/IFR...WITH LIFR AT KLWB IN THE NEXT FEW HOURS. THUS DELAYED ONSET OF LOWER VSBYS BY A COUPLE OF HOURS IN THE WEST INCLUDING KBCB WHICH MAY NOT DROP TO MVFR UNTIL JUST BEFORE DAWN. APPEARS THE CLOUD SHIELD MAY HOLD FOR MUCH OF THE OVERNIGHT FROM KROA EASTWARD WHICH WOULD CURTAIL MUCH FOG TO MAINLY SPOTTY COVERAGE IN THE LOWER SPOTS BY MORNING. THEREFORE ALSO CUT BACK ON FOG AT BOTH KDAN/KLYH UNTIL VERY LATE AND ONLY WENT WITH A BRIEF PERIOD OF MVFR FOR NOW. EXPECT ANY FOG OR LOW CIGS TO ERODE BY MID MORNING EXCEPT MAY HANG IN A BIT LONGER IN THE VALLEY AROUND KLWB. ELSW SHOULD SEE MAINLY VFR FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND OUT EAST BUT JUST TOO IFFY TO INCLUDE MENTION IN ANY TAF LOCATION AT THIS POINT. PROXIMITY OF OLD FRONT AND TROPICAL AIRMASS JUST TO THE SOUTH... WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL MAINTAIN A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY OF MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF THE WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE OVERNIGHT PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA LIKELY BY WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO DIVE THRU THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING CONDITIONS TO VFR LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST FOR THE WEEKEND. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/WP SHORT TERM...PH LONG TERM...PH AVIATION...DS/JH/KM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1132 AM EDT WED AUG 8 2012 .SYNOPSIS...INCREASING HUMIDITY, PLUS A CANADIAN COLD FRONT MOVING SOUTHWARD TOWARD LAKE ERIE, MAY SPARK SCATTERED THUNDERSTORMS THIS AFTERNOON AND EVENING AND AGAIN LATE THURSDAY ACROSS THE UPPER OHIO VALLEY. LOW PRESSURE, COMING EAST FROM MINNESOTA, WILL JOIN THE COLD FRONT AND BRING MORE NUMEROUS SHOWERS AND THUNDERSTORMS FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... ALTHOUGH SATELLITE DATA AND NAM MODEL PROFILES SHOW SKIES WILL STAY MAINLY SUNNY INTO EARLY AFTERNOON. NAM MODEL PROFILES COMBINED WITH HRRR AND WRF-NMM MODEL OUTPUT, COUPLED WITH RECENT RADAR DATA, SUGGEST ONCE SURFACE TEMPERATURES REACH THE MID 80S, CUMULONIMBUS AND THUNDERSTORMS CAN DEVELOP. HRRR MODEL OUTPUT SPECIFICALLY SHOWS A BAND OF THESE SCATTERED THUNDERSTORMS CAN MOVE SOUTHEASTWARD ACROSS MUCH OF THE UPPER OHIO VALLEY THROUGH EARLY EVENING. STORM INTENSITY WILL NEED MONITORED AS SPC HAS INDICATED SOME SEVERE POTENTIAL. SREF MODEL OUTPUT SUPPORTS THIS IDEA AS IT SHOWS INSTABILITY CAN PEAK ABOVE 1500 J/KG AND VERTICAL WIND SHEAR MAY REACH 30 KTS. FORECASTED HIGH TEMPERATURES IN THE 85 TO 90 RANGE, BUT THESE COULD BE REDUCED IF THUNDERSTORMS PASS THROUGH AN AREA PRIOR TO 5 PM. AFTER DARK, NOCTURNAL COOLING WILL DISSIPATE CONVECTIVE INSTABILITY. PATCHY RIVER VALLEY FOG CAN AGAIN DEVELOP AS IT HAS ON PREVIOUS NIGHTS, AN IDEA SUPPORTED BY RECENT GFS LAMP OUTPUT. FORECASTED LOW TEMPERATURES USING A BLEND OF RECENT NAM AND GFS MOS. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... COLD FRONT WILL BECOME STALLED IN A WEST TO EAST ORIENTATION ACROSS THE UPPER OHIO VALLEY THURSDAY AS AN EASTBOUND UPPER LEVEL SHORTWAVE TROUGH WILL UP THE RISK FOR SHOWERS/STORMS. THIS NEXT UPPER LEVEL SYSTEM WILL HAVE MORE MOISTURE TO TAP INTO AND HAVE A BIT MORE OF A PUNCH, SO THERE SHOULD BE AT LEAST SCATTERED THUNDERSTORMS THURSDAY AND THURSDAY NIGHT. SPC HAS MAINTAINED A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON INTO EARLY FRIDAY, WHICH SREF MODEL OUTPUT PROJECTIONS OF INSTABILITY AND VERTICAL WIND SHEAR SUPPORT. A LARGER SYSTEM, BOTH IN THE UPPER LEVELS AND AT THE SFC WILL MOVE THROUGH THE UPPER OHIO VALLEY FRIDAY, MAKING SHOWERS AND THUNDERSTORMS LIKELY. DUE TO THE PROSPECTS FOR SHOWERS AND ACCOMPANYING CLOUDINESS, CONCURRED WITH GFS AND NAM MOS IN FORECASTING HIGHS THURSDAY NOT AS WARM AS WEDNESDAY AND THEN COOLER THAN NORMAL FRIDAY. CLOUDS AT NIGHT AND HUMID CONDITIONS WILL KEEP LOWS WARMER THAN NORMAL. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... BLEND OF RECENT GFS AND ECMWF MODEL OUTPUT SHOWS THE WELL- DEVELOPED LOW PRESSURE SYSTEM MOVING NORTHWARD PAST THE EASTERN GREAT LAKES THIS WEEKEND. THIS CAN MAINTAIN WRAP-AROUND SHOWERS ACROSS THE UPPER OHIO VALLEY AT LEAST THROUGH SATURDAY WITH THE TREND FOR DRIER CONDITIONS BY SUNDAY. HIGH PRESSURE COMING EAST FROM THE PLAINS SHOULD PROVIDE A DRY PERIOD MONDAY AND PERHAPS TUESDAY. THE EFFECTS OF COOLER TEMPERATURE ALOFT AND INSTABILITY CLOUDS AND SHOWERS WILL PROVIDE COOLER THAN NORMAL TEMPERATURES THIS WEEKEND. LESS CLOUDS MONDAY AND TUESDAY SHOULD ALLOW DAYTIME TEMPERATURES REBOUND TO VALUES NEAR OR SLIGHTLY WARMER THAN NORMAL, AS INDICATED BY RECENT GFS AND ECMWF MOS. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... VFR WILL BE PREVALENT INTO TONIGHT. HOWEVER A WEAK SYSTEM MOVING EASTWARD THROUGH THE AREA THIS AFTERNOON MAY SPAWN A BAND OF SCATTERED THUNDERSTORM WITH POTENTIAL RESTRICTIONS AND WIND GUSTS OVER 25 MPH. HOWEVER CONFIDENCE REGARDING COVERAGE AND TIMING IS STILL TOO LOW TO INCLUDE MENTION IN ANY TAF. .OUTLOOK...THURSDAY THROUGH SATURDAY... RESTRICTIONS ARE POSSIBLE IN SHOWERS AND THUNDERSTORMS, AND PATCHY EARLY MORNING FOG, INTO THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS BILLINGS MT
931 AM MDT WED AUG 8 2012 .SHORT TERM...VALID FOR TDY AND THU... UPDATE TO ZFP AND WRKAFP. A SHORTWAVE WAS SEEN OVER S ID THIS MORNING ON SATELLITE IMAGERY. RADAR SHOWED A BAND OF SHOWERS WITH THE WAVE AS WELL. NEW WRF AND RAP BROUGHT LIFT FROM THE WAVE INTO THE WESTERN MOUNTAINS BY 00Z TONIGHT ALONG WITH SOME PRECIPITATION. KLVM SOUNDING HAD .74 INCHES OF PRECIPITABLE WATER SO SOME MOISTURE WILL BE POSSIBLE WITH THUNDERSTORMS. HAVE ADDED SLIGHT CHANCE POPS TO THE WESTERN MOUNTAINS AND KLVM AREA THIS AFTERNOON. LOW-LEVEL FLOW WILL TURN EASTERLY E OF KBIL THIS AFTERNOON AS SURFACE HIGH OVER S SASKATCHEWAN SLIDES INTO THE DAKOTAS. THIS FLOW WILL CREATE AN INVERSION OVER THE EASTERN ZONES WHICH WILL SLOW TEMPERATURE RISES. THUS HAVE LOWERED MAX TEMPERATURES OVER KMLS AND KBHK AREAS. NO CHANGES TO REMAINDER OF FORECAST. ARTHUR .LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE... MADE A FEW CHANGES TO THE EXTENDED FORECAST AS DETAILS BECOME MORE VISIBLE AND CONSISTENT. ALTHOUGH LOCATED AT THE APEX OF BROAD UPPER LEVEL RIDGE THROUGH MUCH OF THE PERIOD...FLATTENED FLOW WILL ALLOW FOR THE POTENTIAL FOR A FAIRLY ACTIVE PERIOD WITH REGARD TO PRECIP. THE EXTENDED PERIOD BEGINS FRIDAY AS A A STRONG TROF CRASHES THROUGH THE UPPER LEVEL RIDGE. THIS BRINGS OUR BEST CHANCE OF PRECIPITATION ACROSS THE REGION...AS WELL AS RESULTS IN FLATTENING THE RIDGE FOR THE REMAINDER OF THE PERIOD. THE ONLY NEGATIVE IS THAT IT APPEARS TO BE VERY QUICK MOVING. SPLIT THE 00-12Z SATURDAY GRID TO CLEAR OUT WESTERN ZONES MORE QUICKLY BETWEEN FROM 06-12Z. ALSO TAPERED POPS BACK TO THE EAST FURTHER FOR THE 12Z-00Z SATURDAY GRID AS A RESULT OF QUICKER PACE OF THE SYSTEM. PATTERN REMAINS SOMEWHAT ZONAL THROUGH THE BEGINNING OF NEXT WEEK...WITH SEVERAL WAVES THROUGH THE FLOW. THESE WILL BRING SLIGHT CHANCES FOR PRECIP...BUT NOTHING TERRIBLY ORGANIZED TAKES SHAPE UNTIL LATE TUESDAY INTO WEDNESDAY. MODELS ARE STILL DIFFERING SIGNIFICANTLY ON SPECIFICS OF APPROACHING TROF...BUT FAVOR MAJOR COOL OFF AND A MORE PROLONGED PERIOD OF PRECIP TO END THE EXTENDED PERIOD. HAVE INTRODUCED HIGHS IN THE UPPER 80S AND ABOVE CLIMO TYPE SLIGHT POPS. MODELS SEEM TO SUPPORT MUCH COOLER TEMPS...AND HIGH POPS POTENTIAL...BUT IS STILL FAR IN THE FUTURE...AND SYSTEM STILL TAKING SHAPE. ABOVE NORMAL TEMPERATURES WILL CONTINUE THROUGH THE EXTENDED PERIOD...BUT LOOK LIKE THEY SHOULD BE MODERATED SOMEWHAT...ONLY IN LOW 90S FOR MOST PART...DUE TO FLAT FLOW AND MULTIPLE SHORTWAVES THROUGH THE REGION BRINING CLOUD COVER AND PRECIP. AAG && .AVIATION... MAINLY VFR CONDITIONS ARE EXPECTED ACROSS THE AREA TODAY. A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS WESTERN ZONES...NEAR KLVM...THIS AFTERNOON. FLIGHT CONDITIONS COULD BE LOCALLY LOWERED TO MVFR IN AND AROUND THESE STORMS. A FEW OF THESE STORMS COULD PRODUCE SOME ERRATIC GUSTY WINDS AS WELL AS SOME LOCALIZED MOUNTAIN OBSCURATIONS. CHURCH && .PRELIMINARY POINT TEMP/POPS... TDY THU FRI SAT SUN MON TUE ------------------------------------------------------- BIL 098 064/094 061/092 061/091 060/094 060/093 059/091 0/U 12/T 23/T 41/B 11/B 21/B 12/T LVM 095 056/090 053/088 053/088 052/090 051/088 051/087 2/T 33/T 34/T 41/B 22/T 22/T 22/T HDN 100 062/097 062/095 061/094 061/097 060/096 059/094 0/U 12/T 23/T 41/U 22/T 22/T 12/T MLS 094 067/096 064/094 064/092 062/094 063/096 062/092 0/U 12/T 22/T 41/B 22/T 22/T 22/T 4BQ 096 063/096 063/093 062/092 061/094 061/094 060/093 0/U 11/B 22/T 42/T 22/T 22/T 22/T BHK 091 062/091 061/090 061/088 060/089 060/090 061/089 1/U 11/B 22/T 52/T 22/T 22/T 22/T SHR 095 060/093 058/091 058/089 056/092 057/094 056/090 0/U 01/B 23/T 41/B 22/T 22/T 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
909 AM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD FRONT FROM JUST NORTH OF BUF TO JUST SOUTH OF TOL. FORECAST LOOKS REASONABLE. MADE MINOR ADJUSTMENTS TO THE TIMING OF THE CLOUD COVER FOR UPDATE. PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS WILL BE A DEGREE OR TWO COOLER THAN TUESDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE. EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE BELOW NORMAL FOR A CHANGE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... A WEAK COLD FRONT FROM LAKE ERIE ACROSS SRN MI WILL CONTINUE MOVING SOUTH OVER NRN OH TODAY. SATELLITE SHOWING SOME CLOUDS ALONG THE FRONT SO WENT WITH SCT-BKN 060-080 ACROSS SITES. MODELS SHOWING THE POSSIBILITY OF SOME SHRA DEVELOPING ALONG THE FRONT LATER THIS MORNING AND INTO THE AFTERNOON...BUT FOR LOCATIONS SUCH AS TOL-CLE THINKING THAT ANY DEVELOPMENT WOULD OCCUR SOUTH OF THOSE SITES. OVERALL GIVEN LOW PROBABILITIES DID MENTION SOME VCSH AT SEVERAL SITES INCLUDING FDY-MFD-CAK-YNG. TOO LOW CONF AT ERI TO INCLUDE VCSH. ALSO...GIVEN SUCH ISOLATED PROBABILITIES WILL HOLD OFF ON THUNDER AT SITES. SOUTHWEST WINDS SHIFTING W THEN NORTHERLY THROUGH TODAY WITH FROPA. HIGH CLOUDS WILL QUICKLY BUILD IN FROM THE WEST LATE TODAY AND THROUGH TONIGHT WITH NEXT WEATHER SYSTEM. CIGS LOWER TOWARD 10K FT LATER TONIGHT WITH MAINLY NE FLOW DEVELOPING. POSSIBLE MVFR VIS DEVELOPING BUT LATE IN PERIOD SO WILL LET NEXT SHIFT EVALUATE PROBABILITY OF THAT. .OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES. && .MARINE... A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY. HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND CONTINUING THROUGH AT LEAST SATURDAY MORNING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...DJB/KUBINA SHORT TERM...KUBINA LONG TERM...ABE AVIATION...ABE MARINE...ABE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
729 AM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE ALREADY OUT. THE LATEST HRRR NOW SHOWING SCATTERED STORMS DEVELOPING ALONG THE COLD FRONT THIS AFTERNOON. HAVE RAISED PRECIP CHANCES SLIGHTLY OVER THE SE 1/3 OF THE AREA. MINOR ADJUSTMENTS TO THE SKY COVER AS WELL. PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS WILL BE A DEGREE OR TWO COOLER THAN TUESDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE. EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE BELOW NORMAL FOR A CHANGE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... A WEAK COLD FRONT FROM LAKE ERIE ACROSS SRN MI WILL CONTINUE MOVING SOUTH OVER NRN OH TODAY. SATELLITE SHOWING SOME CLOUDS ALONG THE FRONT SO WENT WITH SCT-BKN 060-080 ACROSS SITES. MODELS SHOWING THE POSSIBILITY OF SOME SHRA DEVELOPING ALONG THE FRONT LATER THIS MORNING AND INTO THE AFTERNOON...BUT FOR LOCATIONS SUCH AS TOL-CLE THINKING THAT ANY DEVELOPMENT WOULD OCCUR SOUTH OF THOSE SITES. OVERALL GIVEN LOW PROBABILITIES DID MENTION SOME VCSH AT SEVERAL SITES INCLUDING FDY-MFD-CAK-YNG. TOO LOW CONF AT ERI TO INCLUDE VCSH. ALSO...GIVEN SUCH ISOLATED PROBABILITIES WILL HOLD OFF ON THUNDER AT SITES. SOUTHWEST WINDS SHIFTING W THEN NORTHERLY THROUGH TODAY WITH FROPA. HIGH CLOUDS WILL QUICKLY BUILD IN FROM THE WEST LATE TODAY AND THROUGH TONIGHT WITH NEXT WEATHER SYSTEM. CIGS LOWER TOWARD 10K FT LATER TONIGHT WITH MAINLY NE FLOW DEVELOPING. POSSIBLE MVFR VIS DEVELOPING BUT LATE IN PERIOD SO WILL LET NEXT SHIFT EVALUATE PROBABILITY OF THAT. .OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES. && .MARINE... A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY. HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND CONTINUING THROUGH AT LEAST SATURDAY MORNING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...ABE AVIATION...ABE MARINE...ABE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
627 AM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE ALREADY OUT. THE LATEST HRRR NOW SHOWING SCATTERED STORMS DEVELOPING ALONG THE COLD FRONT THIS AFTERNOON. HAVE RAISED PRECIP CHANCES SLIGHTLY OVER THE SE 1/3 OF THE AREA. MINOR ADJUSTMENTS TO THE SKY COVER AS WELL. PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS WILL BE A DEGREE OR TWO COOLER THAN TUESDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE. EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE BELOW NORMAL FOR A CHANGE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... A WEAK COLD FRONT N OF LAKE ERI ACROSS SRN MI WILL CONTINUE TO SLOWLY MOVE SOUTH ACROSS SITES THROUGH TODAY. RADAR SHOWING ONE ISOL SHRA MOVING INTO NW OH SO WILL HAVE TO WATCH TOL...BUT NOT THINKING MUCH FOR IMPACT. OTHERWISE EXPECTING SOME CLOUDS TO DEVELOP LATER THIS MORNING AND AFTN ACROSS NRN OH AHEAD OF THE FRONT. THERE MAY BE SOME ISOL SHRA WITH IT BUT NOT CONFIDENT ON OCCURRENCE OR TIMING AT ANY PARTICULAR SITES. AT THIS TIME WOULD THINK MFD-CAK-YNG WOULD HAVE BEST CHANCE FOR SHRA THIS AFTN. SOUTH WINDS WILL GRADUALLY TURN NORTH AFTER FROPA THROUGH TODAY. .OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY ACROSS ALL SITES. NON VFR POSSIBLE SATURDAY ACROSS EASTERN SITES. && .MARINE... A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY. HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND CONTINUING THROUGH AT LEAST SATURDAY MORNING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...ABE AVIATION...ABE MARINE...ABE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1112 AM EDT WED AUG 8 2012 .SYNOPSIS... A BROAD UPPER LEVEL TROUGH OVER THE EASTERN U.S. WILL UNDERGO SIGNIFICANT AMPLIFICATION THROUGH THE END OF THE WEEK. THIS FEATURE AND ITS ASSOCIATED FRONTAL SYSTEM WILL BRING RAIN AND THUNDERSTORMS TO THE AREA INTO THE FIRST PART OF THE WEEKEND. FAIR WEATHER SHOULD RETURN BY LATE IN THE WEEKEND OR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... WEAK FRONTAL BOUNDARY ACROSS NW PA WILL BE FOCUS OF SCATTERED CONVECTION THIS AFTERNOON. ANY STORMS THAT DO FORM WILL DRIFT SOUTHEAST ACROSS THE CWA. AFTERNOON CAPES WILL BE MARGINAL AND SHEAR WEAK...THOUGH LATEST HRRR RUNS DEVELOP CONVECTION. WILL RAISE POPS SLIGHTLY IN NW ZONES TO ACCOUNT FOR THIS. STILL NOT EXPECTING MUCH MORE THEN PULSE STORMS. ANOTHER BOUNDARY SE OF PA WILL BE CLOSE ENOUGH TO SE ZONES TO BRING A CHANCE OF AFTERNOON CONVECTION...BUT LACK OF TRIGGER AND WARMER MID LEVEL TEMPS SUGGESTS NOTHING MORE THAN AN ISOLD PULSE STORM. OVERALL CONVECTIVE CVRG SHOULD BE LIMITED AND CAPPED POPS AT 30 PCT. THE WEAK FRONT WILL SETTLE SLOWLY SEWD NEAR I-80 OVERNIGHT. A FEW SHOWERS OR TSTMS MAY STILL LINGER NEAR THE DIFFUSE FRONT...BUT THE LOSS OF HEATING/INSTABILITY SHOULD AFFORD A DRY NIGHT IN MOST LOCATIONS. HI/LO TEMPS THIS PD WILL AVG A FEW TO SEVERAL DEGS ABV NORMAL. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... SIGNIFICANT AMPLIFICATION OF THE ERN TROUGH IS EXPECTED TO BEGIN THIS PERIOD...AS POTENT S/W AND ATTENDANT MID-LVL JET DROP SEWD INTO THE GRT LKS AND MID MS VLY. AT THE SFC...THE BAROCLINIC/FRONTAL ZONE SHOULD BECOME MORE DEFINED IN TIME WITH ONE OR MORE SFC WAVES DEVELOPING IN THE OH VLY. THE ERN PORTION OF THE WAVY FNTL BNDRY SHOULD REMAIN Q-STNRY OVR CENTRAL PA THRU THURS NIGHT. SPC HAS MAINTAINED THE SLIGHT RISK FOR ALL OF THE CWA FOR D2. THE SLIGHTLY ELEVATED SVR THREAT..WHEN COMPARED TO THE D1 SEE TEXT... IS SUPPORTED BY STRONGER DEEP LYR FORCING/HEIGHT FALLS AND WINDS ALOFT. 1500-2000 J/KG OF ML CAPE AND FAIRLY STEEP MID-LVL LAPSE RATES SHOULD ALSO ENHANCE DMGG WIND THREAT VIA LOOSELY ORGANIZED MULTI-CELL CLUSTERS. THE WELL-DEFINED POS TILT S/W TROUGH WILL ROTATE EWD THRU THE MIDWEST TWD THE UPPER OH VLY BY THE END OF THE PD. MDL DATA SHOWS AN AXIS OF MOD-HVY RNFL SETTING UP ALONG SEWD ADVANCING FNTL ZONE JUST DOWNWIND OF THE LWR GRT LKS. INC SWLY FLOW AHEAD OF DEEPENING SFC WAVE EJECTING NEWD THRU THE OH VLY SHOULD DRAW HI PWATS NEWD INTO NW PA. FAVORABLE UPPER JET DYNAMICS AND STRONG LLVL CONVERGENCE SHOULD SUPPORT 0.50-1 INCH QPF AXIS OVR THIS REGION AND HAVE INCREASED POPS INTO THE LOW CATG RANGE. A NON-GFS SOLUTION IS PREFERRED WITH THIS SYSTEM. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE ANOMALOUS MID-UPPER TROUGH IS FORECAST TO EVOLVE INTO A CLOSED LOW INVOF LWR MI ON FRIDAY...AND THEN LIFT SLOWLY NWD ACRS THE LWR GRT LKS INTO SRN ONT ON SAT BEFORE ACCELERATING INTO QUEBEC ON SUNDAY. CONCERNING THE H5 LOW POSITION...THE GFS IS A NRN OUTLIER WITH THIS SYSTEM AND THE 00Z GEFS AND 12Z ECENS MEAN SUPPORT A MORE SOUTHERLY/SLOWER SOLUTION ALOFT PER THE REMAINING DETERMINISTIC GLOBAL MODEL CONSENSUS -- 00Z UKMET/CANADIAN/ECMWF. SEVERAL WEAK WAVES OF LOW PRES IN THE OH VLY WILL CONSOLIDATE INTO ONE MAIN SFC LOW INVOF LAKE ERIE EARLY FRI BEFORE OCCLUDING NWWD OVR THE LWR LKS TWD LAKE HURON BY SATURDAY. THE WARM FRONT ATTENDANT TO THE SFC LOW WILL LIFT NEWD THRU PA INTO NEW ENGLAND WHILE THE TRAILING COLD FRONT PIVOTS EWD ACRS THE UPPER OH VLY AND PUSHES SLOWLY EWD THRU CENTRAL PA. A SSW-NNE ORIENTED MOD-HVY QPF AXIS SHOULD BE ONGOING AT THE START OF THE PERIOD ACRS NW PA NEAR SFC LOW TRACK. GENERALLY LIGHTER BASIN-AVG QPF AMTS...MORE CONVECTIVE IN NATURE... ARE ANTICIPATED FURTHER TO THE EAST ACRS THE CENTRAL MTNS AND SUSQ VLY LATER FRIDAY AND INTO FRI NGT ALONG/AHEAD OF THE COLD FRONT. STRONG JET DYNAMICS AND FRONTAL LIFT/CONVERGENCE COULD PRODUCE HVY RNFL RATES WITH PLENTY OF DEEP LYR MSTR AVAILABLE. FOLLOWED HPC PRETTY CLOSELY FOR QPF AMTS WHICH RANGE FROM 1-1.5 INCHES OVR THE NW MTNS TO 0.25-0.50 IN THE LWR SUSQ VLY FOR THE 24HR PD ENDING 00Z SAT. IN ADDITION TO POSSIBLE HVY RAINS...A SVR WEATHER THREAT SHOULD ALSO UNFOLD AHEAD OF THE COLD FRONT IN THE VERY MOIST WARM SECTOR. SPC HAS EXPANDED THE D3 SLIGHT RISK TO ENCOMPASS NEARLY ALL OF THE CWA EAST OF THE ALLEGHENY FRONT. THERE WILL BE A SOMEWHAT CONDITIONAL DMGG WIND THREAT AS STRONG WARMING OCCURS IN CLOUD-BREAKS AND CONTRIBUTES TO POTENTIAL MODERATE INSTABILITY. ANOTHER SCENARIO TO CONSIDER IS THE DEVELOPMENT OF A SECONDARY TRIPLE POINT LOW E OF THE APPLCHNS...WHICH MAY ACT TO ENHANCE LOW LEVEL SHEAR INVOF WARM FRONTAL ZONE NEAR SE PA. BROAD CYC FLOW ALOFT WILL OVERSPREAD THE REGION SAT INTO EARLY SUNDAY WHICH SHOULD ALLOW FOR SCT SHOWER/ISOLD TSTM ACTIVITY. THERE ALSO APPEARS TO BE A DEFORMATION ZONE WHICH COULD SPREAD WRAP- AROUND PCPN INTO THE AREA ON THE BACKSIDE OF THE DEPARTING SYS. PCPN SHOULD COME TO AN END ON SUNDAY AS THE SYSTEM BEGINS TO ACCELERATE NWD. A PERIOD OF FAIR AND FAIRLY UNEVENTFUL WEATHER WILL LKLY FOLLOW INTO EARLY NEXT WEEK AS THE WESTERLIES RELAX TO A QUASI-ZONAL ORIENTATION. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... A WEAKENING COLD FRONT MAY SPARK OFF SOME SCATTERED SHOWERS/STORMS OVER THE NWRN HALF OF THE FCST AREA LATE IN THE DAY...BUT CONFIDENCE IS LOW AS THE FORCING WILL BE WEAK AND PWATS WILL BE NOMINAL. OUTLOOK... THU...VFR WITH SCT SHRA/TSRA POSS AFTN/NIGHT. FRI-SAT...MAINLY VFR BUT RESTRICTIONS LIKELY IN TSRA/SHRA. SUN...SCATTERED SHOWERS/THUNDERSTORMS. RESTRICTIONS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...ROSS SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...ROSS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
957 AM EDT WED AUG 8 2012 .SYNOPSIS... A STATIONARY FRONT ACROSS THE MOUNTAINS WILL GRADUALLY DISSIPATE TODAY AS WEAK HIGH PRESSURE SLIDES EAST INTO THE REGION BY TONIGHT BEFORE WEAKENING ON THURSDAY. A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION FRIDAY INTO FRIDAY EVENING...BRINGING ANOTHER ROUND OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND DRIER WEATHER IS EXPECTED BEHIND THE FRONT OVER THE WEEKEND INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION. && .NEAR TERM /THROUGH TONIGHT/... AS OF 952 AM EDT WEDNESDAY... SURFACE OBSERVATIONS AND VISIBLE SATELLITE IMAGERY INDICATES A FEW POCKETS OF LINGERING FOG IN SOME OF THE MOUNTAIN VALLEYS. HOWEVER...ANTICIPATE THAT BY 1100 AM EDT...MOST OR ALL OF THIS LINGERING FOG WILL HAVE DISSIPATED. PRECIPITATION HAS BEEN LIMITED TO JUST A FEW ISOLATED SHOWERS ACROSS PARTS OF BUCKINGHAM COUNTY VIRGINIA. ANTICIPATE LIMITED...IF ANY COVERAGE...THROUGH NOON BEFORE COVERAGE INCREASES NEAR THE NC/VA BORDER. NO OTHER SIGNIFICANT CHANGES. THE HOURLY TEMPERATURE...DEW POINT...WIND AND SKY COVER GRIDS HAVE BEEN TWEAKED TO REFLECT THE LATEST OBSERVATIONS AND EXPECTED TRENDS INTO THE EARLY AFTERNOON. AS OF 230 AM EDT WEDNESDAY... WEAK SURFACE BOUNDARY ACROSS THE MOUNTAINS WILL GRADUALLY FADE TODAY AS A MID LEVEL WAVE PASSES TO THE EAST BY AFTERNOON AND DRIER AIR ALOFT PER VAPOR LOOP ADVECTS IN FROM THE NW. HOWEVER THE LOW LEVELS WILL REMAIN RATHER MOIST AND GIVEN ANOTHER SUBTLE S/W PUSHING ACROSS THE WEST LATER ON CANT TOTALLY RULE OUT ADDED ISOLATED CONVECTION...ESPCLY BLUE RIDGE AND POINTS EAST...MAINLY SOUTH OF HIGHWAY 460 WHERE BOUNDARY LAYER MOISTURE/INSTABILITY WILL BE BETTER. LATEST LOCAL GUIDANCE AS WELL AS THE SPC WRF AND GFS HINT AT THIS WITH A FEW TSRA CLUSTERS DEVELOPING SW SECTIONS ALONG THE BLUE RIDGE PER DIFF HEATING UNDER WEAK THETA-E RIDGING...AND THEN OUT EAST JUST AHEAD OF WHAT WAS LEFT OF THE OLD FRONT. AGAIN GIVEN WEAK STEERING AND LOCAL CONVERGENCE/OUTFLOW COULD ALLOW FOR STORMS TO POP UP AND DUMP HEAVY RAINFALL BUT NOT THINKING MUCH MORE COVERAGE THAN CHANCE TO ISOLATED POPS TODAY. OTRW EXPECTING A GRADUAL RETURN TO MORE SUNSHINE AS THE HIGH/MID LEVEL CLOUD DECK ERODES AND SHIFTS NE WITH THE PASSAGE OF THE WAVE TO THE EAST THIS MORNING. THINK CLOUDS WILL LIMIT FOG FROM BECOMING TOO WIDESPREAD EXCEPT PERHAPS THE FAR WEST SO WILL KEEP MENTION PENDING RELEASE COVERAGE. WARM START AND SLIGHT 85H WARMING UNDER A WEAK WEST/NW TRAJECTORY ALOFT SHOULD PUSH TEMPS TO AROUND 90 EAST AND WELL INTO THE 80S WEST SO BUMPED UP CLOSER TO THE MAV VALUES TODAY. ANY CONVECTION SHOULD QUICKLY FADE WITH LOSS OF HEATING THIS EVENING GIVEN LACK OF SUPPORT...WITH MAINLY CLEAR SKIES AFTER MIDNIGHT AS WE SLIDE IN BETWEEN THE DEEP MOISTURE LOBE TO THE SE AND THE NEXT UPSTREAM 5H TROF. THUS WILL CARRY SOME ISOLATED EVENING POPS MAINLY SOUTH/EAST THEN GO DRY WITH PERHAPS SOME PATCHY FOG UNDER WEAK HIGH PRESSURE LATE. THIS SHOULD ALSO ALLOW LOW TEMPS TO DROP CLOSER TO THE COOLER MAV FOR THE MOST PART WITH RANGE FROM AROUND 60 VALLEYS TO UPPER 60S SE AND RIDGES. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 430 AM EDT WEDNESDAY... ACTIVE WEATHER WILL BEGIN THE SHORT TERM PERIODS AS THE UPPER FLOW AMPLIFIES ACROSS THE U.S...FEATURING A DEEPENING NEGATIVELY TILTED UPPER TROUGH FROM THE GREAT LAKES TOWARD THE MID-ATLANTIC THU-FRI. THE POPS AND SEVERE THREAT FOR THU SOMEWHAT QUESTIONABLE...BUT A MORE DEFINITE POSSIBILITY FOR FRI AS THE ENTIRE SYSTEM SHIFTS ACROSS THE CWA. NORMALLY SUCH A PATTERN WOULD SUGGEST A HIGH THREAT OF SEVERE WX ACROSS THE REGION...ESPECIALLY FRI. HOWEVER...EXTENSIVE CLOUD COVER AND MORNING SHRA FRI WILL LIKELY LIMIT HEATING...WITH THE GREATER LIKELIHOOD FOR SEVERE PROBABLY FOCUSED ACROSS THE PIEDMONT AND TOWARD THE COASTAL PLAIN FRI AFTERNOON/EVENING. AT THIS POINT...HAVE ONLY MENTIONED GUSTY WINDS AND LOCALLY HEAVY RAIN. SPC HAS OUTLOOKED THE WESTERN SECTIONS ON DAY2 AND THE ENTIRE CWA ON DAY3...BUT AGAIN FEEL MAIN THREAT ON DAY3 SHOULD BE EAST OF THE BLUE RIDGE. MODEL AND HPC QPF NOT OVERLY IMPRESSIVE AND INDICATIVE OF A SKIP OVER EFFECT OF THE HEAVIEST PRECIPITATION AS AFOREMENTIONED TOWARD EASTERN VA/NC. NONETHELESS...WITH FAIRLY WIDESPREAD HEAVY RAIN ACROSS THE MOUNTAIN AREAS DURING THE PAST COUPLE OF WEEKS...LATER SHIFTS WILL NEED TO EVALUATE THE ISSUANCE OF AN FFA WEST OF THE BLUE RIDGE WHERE 1HR FFG VALUES GENERALLY LESS THAN 2 INCHES. WITH REFERENCE TO POP TIMING...ENOUGH FORCING APPEARS EVIDENT COMBINED WITH PRE-SYSTEM HEATING TO SUPPORT GOOD CHC POPS EAST TO LIKELY POPS WEST BY FRI EVENING. WILL HAVE LIKELY POPS TO ALL AREAS FRI...WHICH MAY WELL BECOME CATEGORICAL WITH LATER FORECASTS. 850MB TEMPS NEAR +20C ACROSS THE PIEDMONT REGION THU WILL STILL SUPPORT WELL ABOVE NORMAL TEMPS IN THE LOW TO MID 90S EAST OF THE BLUE RIDGE...WITH MOSTLY 80S TO THE WEST...EXCEPT 70S IN THE MOUNTAINS ABOVE 3000 FT. EXTENSIVE CLOUD COVER AND SHRA/TSRA FRI SHOULD HOLD TEMPS TO THE 70S IN THE MOUNTAINS TO 80S EAST OF THE BLUE RIDGE. LATEST MODELS HAVE COME INTO BETTER AGREEMENT IN PUSHING THE MAIN UPPER TROUGH EAST OF THE REGION BY EARLY SAT...WHICH SHOULD TAKE THE BULK OF THE PCPN WITH IT. HOWEVER...THE PARENT...RATHER DEEP UPPER LOW FOR MID-AUGUST...WILL SWEEP THROUGH CENTRAL PA SAT AND COULD PROMOTE ENOUGH LIFT IN UPSLOPE AREAS OF WV/N VA TO SUPPORT ISOLD -SHRA DURING DAYTIME HEATING...THUS HAVE INCLUDED SLIGHT CHC POPS ACCORDINGLY. 850MB TEMPS DROP TO THE LOWEST LEVELS SEEN IN OVER TWO MONTHS...WITH +10C ACROSS ALL EXCEPT THE PIEDMONT BY 12Z SAT. THIS SHOULD ALLOW FOR SOME RATHER REFRESHING HIGHS IN THE 70S WEST OF THE BLUE RIDGE AND 80S EAST...WITH DEWPOINTS DROPPING INTO THE 50S WEST OF THE BLUE RIDGE AND 60S ACROSS THE PIEDMONT. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 430 AM EDT WEDNESDAY... HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM AT THIS TIME. IT APPEARS THAT A RATHER UNSETTLED WEATHER PATTERN WILL REMAIN IN PLACE THROUGHOUT THE EXTENDED AS A SERIES OF NW FLOW DISTURBANCES TRACK ACROSS THE REGION. THE ECMWF/GFS ARE AT ODDS WITH RESPECT TO THE AMPLIFICATION OF THE NEXT UPPER TROUGH TOWARD THE MIDDLE OF NEXT WEEK... WITH THE GFS FAVORING A FLATTER...MORE ZONAL FLOW. AT ANY RATE...IT APPEARS THAT AT LEAST CHC POPS FOR SHRA/TSRA WILL CONTINUE THROUGHOUT THE EXTENDED WITH TEMPS RETURNING BACK TO AOA NORMAL LEVELS. LOW-LEVEL MOISTURE WILL ALSO BE INCREASING...RESULTING IN INCREASINGLY MORE HUMID CONDITIONS AS WELL. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 645 AM EDT WEDNESDAY... EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET CONTINUES TO SLOWLY PUSH EAST AND SHOULD EXIT THE AREA BY MID MORNING IF NOT SOONER. MAY SEE A FEW ADDED SHRA DEVELOP OVER THE SW THIS MORNING BUT MOSTLY SOUTH OF THE TAF SITES. OTRW FOG THE MAIN CONCERN AGAIN EARLY THIS MORNING WITH AREAS OF IFR/LIFR IN THE VALLEYS/ALONG THE WESTERN RIDGES...PRIMARILY KLWB/KBLF AND KBCB IN THE WEST AND KLYH IN THE EAST. MAY STILL SEE A BRIEF PERIOD OF MVFR IN FOG AT KDAN OTRW VFR AROUND KROA. SHOULD SEE MOST OF THE FOG/STRATUS ERODE BY 14Z...10AM WITH ONLY KLWB LIKELY HANGING ONTO POCKETS OF LOWER VSBYS A WHILE LONGER. ONCE THE FOG FADES AND THE MID DECK EXITS SHOULD SEE MAINLY VFR FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND OUT EAST SO INCLUDED A VCTS MENTION FROM KROA EAST BASED ON THE LATEST HRRR MODEL WHICH SHOWS A FEW CLUSTERS DEVELOPING FROM NW NC INTO THE VA PIEDMONT BY MID AFTERNOON. ELSW WILL LEAVE OUT FOR NOW GIVEN ISOLATED NATURE. AGAIN EXPECT ANY STORMS TO DIMINISH WITH LOSS OF HEATING FOLLOWED BY MAINLY CLEAR SKIES WITH ANOTHER ROUND OF MVFR/IFR FOG ESPCLY VALLEYS GIVEN LESS CLOUD COVER OVERNIGHT. PROXIMITY OF THE OLD FRONT AND TROPICAL AIRMASS JUST TO THE SOUTH... WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL MAINTAIN A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY OF MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF THE WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE OVERNIGHT PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA LIKELY BY WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO DIVE THRU THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING CONDITIONS TO VFR LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST FOR THE WEEKEND. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH NEAR TERM...DS/JH SHORT TERM...RAB LONG TERM...PH/RAB AVIATION...DS/JH/KM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
731 AM EDT WED AUG 8 2012 .SYNOPSIS... A STATIONARY FRONT ACROSS THE MOUNTAINS WILL GRADUALLY DISSIPATE TODAY AS WEAK HIGH PRESSURE SLIDES EAST INTO THE REGION BY TONIGHT BEFORE WEAKENING ON THURSDAY. A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION FRIDAY INTO FRIDAY EVENING...BRINGING ANOTHER ROUND OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND DRIER WEATHER IS EXPECTED BEHIND THE FRONT OVER THE WEEKEND INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION. && .NEAR TERM /THROUGH TONIGHT/... AS OF 230 AM EDT WEDNESDAY... WEAK SURFACE BOUNDARY ACROSS THE MOUNTAINS WILL GRADUALLY FADE TODAY AS A MID LEVEL WAVE PASSES TO THE EAST BY AFTERNOON AND DRIER AIR ALOFT PER VAPOR LOOP ADVECTS IN FROM THE NW. HOWEVER THE LOW LEVELS WILL REMAIN RATHER MOIST AND GIVEN ANOTHER SUBTLE S/W PUSHING ACROSS THE WEST LATER ON CANT TOTALLY RULE OUT ADDED ISOLATED CONVECTION...ESPCLY BLUE RIDGE AND POINTS EAST...MAINLY SOUTH OF HIGHWAY 460 WHERE BOUNDARY LAYER MOISTURE/INSTABILITY WILL BE BETTER. LATEST LOCAL GUIDANCE AS WELL AS THE SPC WRF AND GFS HINT AT THIS WITH A FEW TSRA CLUSTERS DEVELOPING SW SECTIONS ALONG THE BLUE RIDGE PER DIFF HEATING UNDER WEAK THETA-E RIDGING...AND THEN OUT EAST JUST AHEAD OF WHAT WAS LEFT OF THE OLD FRONT. AGAIN GIVEN WEAK STEERING AND LOCAL CONVERGENCE/OUTFLOW COULD ALLOW FOR STORMS TO POP UP AND DUMP HEAVY RAINFALL BUT NOT THINKING MUCH MORE COVERAGE THAN CHANCE TO ISOLATED POPS TODAY. OTRW EXPECTING A GRADUAL RETURN TO MORE SUNSHINE AS THE HIGH/MID LEVEL CLOUD DECK ERODES AND SHIFTS NE WITH THE PASSAGE OF THE WAVE TO THE EAST THIS MORNING. THINK CLOUDS WILL LIMIT FOG FROM BECOMING TOO WIDESPREAD EXCEPT PERHAPS THE FAR WEST SO WILL KEEP MENTION PENDING RELEASE COVERAGE. WARM START AND SLIGHT 85H WARMING UNDER A WEAK WEST/NW TRAJECTORY ALOFT SHOULD PUSH TEMPS TO AROUND 90 EAST AND WELL INTO THE 80S WEST SO BUMPED UP CLOSER TO THE MAV VALUES TODAY. ANY CONVECTION SHOULD QUICKLY FADE WITH LOSS OF HEATING THIS EVENING GIVEN LACK OF SUPPORT...WITH MAINLY CLEAR SKIES AFTER MIDNIGHT AS WE SLIDE IN BETWEEN THE DEEP MOISTURE LOBE TO THE SE AND THE NEXT UPSTREAM 5H TROF. THUS WILL CARRY SOME ISOLATED EVENING POPS MAINLY SOUTH/EAST THEN GO DRY WITH PERHAPS SOME PATCHY FOG UNDER WEAK HIGH PRESSURE LATE. THIS SHOULD ALSO ALLOW LOW TEMPS TO DROP CLOSER TO THE COOLER MAV FOR THE MOST PART WITH RANGE FROM AROUND 60 VALLEYS TO UPPER 60S SE AND RIDGES. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 430 AM EDT WEDNESDAY... ACTIVE WEATHER WILL BEGIN THE SHORT TERM PERIODS AS THE UPPER FLOW AMPLIFIES ACROSS THE U.S...FEATURING A DEEPENING NEGATIVELY TILTED UPPER TROUGH FROM THE GREAT LAKES TOWARD THE MID-ATLANTIC THU-FRI. THE POPS AND SEVERE THREAT FOR THU SOMEWHAT QUESTIONABLE...BUT A MORE DEFINITE POSSIBILITY FOR FRI AS THE ENTIRE SYSTEM SHIFTS ACROSS THE CWA. NORMALLY SUCH A PATTERN WOULD SUGGEST A HIGH THREAT OF SEVERE WX ACROSS THE REGION...ESPECIALLY FRI. HOWEVER...EXTENSIVE CLOUD COVER AND MORNING SHRA FRI WILL LIKELY LIMIT HEATING...WITH THE GREATER LIKELIHOOD FOR SEVERE PROBABLY FOCUSED ACROSS THE PIEDMONT AND TOWARD THE COASTAL PLAIN FRI AFTERNOON/EVENING. AT THIS POINT...HAVE ONLY MENTIONED GUSTY WINDS AND LOCALLY HEAVY RAIN. SPC HAS OUTLOOKED THE WESTERN SECTIONS ON DAY2 AND THE ENTIRE CWA ON DAY3...BUT AGAIN FEEL MAIN THREAT ON DAY3 SHOULD BE EAST OF THE BLUE RIDGE. MODEL AND HPC QPF NOT OVERLY IMPRESSIVE AND INDICATIVE OF A SKIP OVER EFFECT OF THE HEAVIEST PRECIPITATION AS AFOREMENTIONED TOWARD EASTERN VA/NC. NONETHELESS...WITH FAIRLY WIDESPREAD HEAVY RAIN ACROSS THE MOUNTAIN AREAS DURING THE PAST COUPLE OF WEEKS...LATER SHIFTS WILL NEED TO EVALUATE THE ISSUANCE OF AN FFA WEST OF THE BLUE RIDGE WHERE 1HR FFG VALUES GENERALLY LESS THAN 2 INCHES. WITH REFERENCE TO POP TIMING...ENOUGH FORCING APPEARS EVIDENT COMBINED WITH PRE-SYSTEM HEATING TO SUPPORT GOOD CHC POPS EAST TO LIKELY POPS WEST BY FRI EVENING. WILL HAVE LIKELY POPS TO ALL AREAS FRI...WHICH MAY WELL BECOME CATEGORICAL WITH LATER FORECASTS. 850MB TEMPS NEAR +20C ACROSS THE PIEDMONT REGION THU WILL STILL SUPPORT WELL ABOVE NORMAL TEMPS IN THE LOW TO MID 90S EAST OF THE BLUE RIDGE...WITH MOSTLY 80S TO THE WEST...EXCEPT 70S IN THE MOUNTAINS ABOVE 3000 FT. EXTENSIVE CLOUD COVER AND SHRA/TSRA FRI SHOULD HOLD TEMPS TO THE 70S IN THE MOUNTAINS TO 80S EAST OF THE BLUE RIDGE. LATEST MODELS HAVE COME INTO BETTER AGREEMENT IN PUSHING THE MAIN UPPER TROUGH EAST OF THE REGION BY EARLY SAT...WHICH SHOULD TAKE THE BULK OF THE PCPN WITH IT. HOWEVER...THE PARENT...RATHER DEEP UPPER LOW FOR MID-AUGUST...WILL SWEEP THROUGH CENTRAL PA SAT AND COULD PROMOTE ENOUGH LIFT IN UPSLOPE AREAS OF WV/N VA TO SUPPORT ISOLD -SHRA DURING DAYTIME HEATING...THUS HAVE INCLUDED SLIGHT CHC POPS ACCORDINGLY. 850MB TEMPS DROP TO THE LOWEST LEVELS SEEN IN OVER TWO MONTHS...WITH +10C ACROSS ALL EXCEPT THE PIEDMONT BY 12Z SAT. THIS SHOULD ALLOW FOR SOME RATHER REFRESHING HIGHS IN THE 70S WEST OF THE BLUE RIDGE AND 80S EAST...WITH DEWPOINTS DROPPING INTO THE 50S WEST OF THE BLUE RIDGE AND 60S ACROSS THE PIEDMONT. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 430 AM EDT WEDNESDAY... HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM AT THIS TIME. IT APPEARS THAT A RATHER UNSETTLED WEATHER PATTERN WILL REMAIN IN PLACE THROUGHOUT THE EXTENDED AS A SERIES OF NW FLOW DISTURBANCES TRACK ACROSS THE REGION. THE ECMWF/GFS ARE AT ODDS WITH RESPECT TO THE AMPLIFICATION OF THE NEXT UPPER TROUGH TOWARD THE MIDDLE OF NEXT WEEK... WITH THE GFS FAVORING A FLATTER...MORE ZONAL FLOW. AT ANY RATE...IT APPEARS THAT AT LEAST CHC POPS FOR SHRA/TSRA WILL CONTINUE THROUGHOUT THE EXTENDED WITH TEMPS RETURNING BACK TO AOA NORMAL LEVELS. LOW-LEVEL MOISTURE WILL ALSO BE INCREASING...RESULTING IN INCREASINGLY MORE HUMID CONDITIONS AS WELL. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 645 AM EDT WEDNESDAY... EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET CONTINUES TO SLOWLY PUSH EAST AND SHOULD EXIT THE AREA BY MID MORNING IF NOT SOONER. MAY SEE A FEW ADDED SHRA DEVELOP OVER THE SW THIS MORNING BUT MOSTLY SOUTH OF THE TAF SITES. OTRW FOG THE MAIN CONCERN AGAIN EARLY THIS MORNING WITH AREAS OF IFR/LIFR IN THE VALLEYS/ALONG THE WESTERN RIDGES...PRIMARILY KLWB/KBLF AND KBCB IN THE WEST AND KLYH IN THE EAST. MAY STILL SEE A BRIEF PERIOD OF MVFR IN FOG AT KDAN OTRW VFR AROUND KROA. SHOULD SEE MOST OF THE FOG/STRATUS ERODE BY 14Z...10AM WITH ONLY KLWB LIKELY HANGING ONTO POCKETS OF LOWER VSBYS A WHILE LONGER. ONCE THE FOG FADES AND THE MID DECK EXITS SHOULD SEE MAINLY VFR FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND OUT EAST SO INCLUDED A VCTS MENTION FROM KROA EAST BASED ON THE LATEST HRRR MODEL WHICH SHOWS A FEW CLUSTERS DEVELOPING FROM NW NC INTO THE VA PIEDMONT BY MID AFTERNOON. ELSW WILL LEAVE OUT FOR NOW GIVEN ISOLATED NATURE. AGAIN EXPECT ANY STORMS TO DIMINISH WITH LOSS OF HEATING FOLLOWED BY MAINLY CLEAR SKIES WITH ANOTHER ROUND OF MVFR/IFR FOG ESPCLY VALLEYS GIVEN LESS CLOUD COVER OVERNIGHT. PROXIMITY OF THE OLD FRONT AND TROPICAL AIRMASS JUST TO THE SOUTH... WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL MAINTAIN A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY OF MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF THE WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE OVERNIGHT PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA LIKELY BY WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO DIVE THRU THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING CONDITIONS TO VFR LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST FOR THE WEEKEND. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...RAB LONG TERM...PH/RAB AVIATION...DS/JH/KM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
250 PM EDT WED AUG 8 2012 .SYNOPSIS... INCREASING HUMIDITY, PLUS A CANADIAN COLD FRONT MOVING SOUTHWARD TOWARD LAKE ERIE, MAY SPARK SCATTERED THUNDERSTORMS THIS AFTERNOON AND EVENING AND AGAIN LATE THURSDAY ACROSS THE UPPER OHIO VALLEY. LOW PRESSURE, COMING EAST FROM MINNESOTA, WILL JOIN THE COLD FRONT AND BRING MORE NUMEROUS SHOWERS AND THUNDERSTORMS FRIDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... RECENT RADAR DATA NOW SHOWS A BAND OF SCATTERED THUNDERSTORMS DEVELOPING ALONG THE LAKE ERIE BREEZE FRONT. WITH SURFACE DEW POINTS HAVING INCREASED INTO THE 60 TO 65 RANGE ACROSS NORTHERN OHIO AND THE PENNSYLVANIA I-80 CORRIDOR, EXPECT THESE STORMS TO EXPAND IN COVERAGE AND MOVE SOUTHEASTWARD INTO EAST CENTRAL OHIO AND WEST CENTRAL PENNSYLVANIA BEFORE 6 PM, A SCENARIO PREDICTED BY RECENT HRRR MODEL OUTPUT. STORM INTENSITY WILL NEED MONITORED AS SPC CONTINUES TO PROJECT SOME SEVERE POTENTIAL. SREF MODEL OUTPUT SUPPORTS THIS IDEA AS IT SHOWS INSTABILITY CAN PEAK ABOVE 1500 J/KG AND VERTICAL WIND SHEAR MAY REACH 30 KTS. FORECASTED HIGH TEMPERATURES IN THE 85 TO 90 RANGE, BUT SUCH HIGHS COULD BE REDUCED IF THUNDERSTORMS PASS THROUGH AN AREA PRIOR TO 5 PM. AFTER DARK, NOCTURNAL COOLING WILL DISSIPATE CONVECTIVE INSTABILITY. PATCHY RIVER VALLEY FOG CAN AGAIN DEVELOP AS IT HAS ON PREVIOUS NIGHTS, AN IDEA SUPPORTED BY RECENT GFS LAMP OUTPUT. FORECASTED LOW TEMPERATURES USING A BLEND OF RECENT NAM AND GFS MOS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... RECENT SREF MODEL OUTPUT, WITH DETAILS FROM THE NAM, SHOW THE COLD FRONT WILL BECOME STALLED, IN A WEST TO EAST ORIENTATION, ACROSS THE UPPER OHIO VALLEY THURSDAY. EXPECT BANDS OF SCATTERED THUNDERSTORMS TO DEVELOP DAYTIME THURSDAY, DUE TO LOW LEVEL CONVERGENCE IN ADVANCE OF A LOW PRESSURE CENTER COMING EAST FROM MINNESOTA AND IOWA. SPC HAS MAINTAINED A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON INTO EARLY FRIDAY, WHICH IS SUPPORTED BY SREF MODEL OUTPUT PROJECTIONS OF INSTABILITY, CAPE 2000+ J/KG, AND VERTICAL WIND SHEAR, EFFECTIVE BULK SHEAR 25 KTS. EXPECT SHOWERS AND THUNDERSTORMS TO BE LIKELY FRIDAY DAYTIME AND EARLY EVENING WITH THE NORTHEAST PASSAGE OF THE DEEPENING LOW PRESSURE CENTER. CONCUR WITH HPC THAT WIDESPREAD RAIN AMOUNTS CAN EXCEED 0.50 INCHES, IF NOT 1 INCH. AS THE LOW PRESSURE CENTER MOVES NORTHWARD PAST LAKE ERIE LATE FRIDAY NIGHT AND DAYTIME SATURDAY, EXPECT WRAP-AROUND SHOWERS TO DECREASE IN COVERAGE. DUE TO THE PROSPECTS FOR SHOWERS AND ACCOMPANYING CLOUDINESS, CONCURRED WITH GFS AND NAM MOS IN FORECASTING HIGHS THURSDAY NOT AS WARM AS WEDNESDAY AND THEN COOLER THAN NORMAL FRIDAY. CLOUDS AT NIGHT AND HUMID CONDITIONS WILL KEEP LOWS WARMER THAN NORMAL THURSDAY NIGHT. LOWS FRIDAY NIGHT AND HIGHS SATURDAY CAN BE SLIGHTLY COOLER THAN NORMAL DUE TO COOLER AIR ALOFT. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... WRAPAROUND PRECIPITATION SHOULD BE SHIFTING TO THE NORTHEAST BY SATURDAY NIGHT...AND HAVE REMOVED PRECIPITATION AFTER MIDNIGHT. 00Z GFS SEEMS TO BE AN OUTLIER IN SHOWING DIURNAL PRECIPITATION FOR NEXT WEEK. OTHER MODEL CONSENSUS KEEPS HIGH PRESSURE THROUGH THE PERIOD...AND HAVE STUCK WITH THIS DRY DEPICTION. SUNDAY AND MONDAY SHOULD CONTINUE THE TREND OF SLIGHTLY BELOW NORMAL TEMPERATURES, WITH A SLIGHT RISE IN HIGHS ON TUESDAY AND WEDNESDAY. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... WEAK FRONT WILL APPROACH THE REGION AND BECOME STATIONARY OVERNIGHT. THE FRONT OR A LAKE BREEZE BOUNDARY OFF LAKE ERIE COULD SPAWN SOME SCATTERED SHOWERS/THUNDERSTORMS DURING THE AFTERNOON AND EARLY EVENING HOURS. CONFIDENCE IS STILL NOT HIGH ENOUGH IN ANY SINGLE LOCATION TO BE SPECIFIC ABOUT TAF MENTION. OVERNIGHT...ALL GUIDANCE SUGGESTS A DROP TO AT LEAST MVFR VISIBILITY...IF NOT LOWER. ALTHOUGH WINDS SHOULD DROP TO 2-3 KTS OVERNIGHT...THINK THAT THE POSSIBILITY FOR FOG WILL BE DEPENDENT ON WHERE SHOWERS OCCUR DURING THE AFTERNOON. FOR NOW...WILL ADD MVFR VISIBILITIES AND ALLOW LATER TAF ISSUANCES TO DECIDE IF IFR VISIBILITIES ARE REQUIRED IN FORECAST. MID LEVEL CLOUDS WILL MOVE IN ON THURSDAY...WITH SCATTERED SHOWERS/STORMS EXPECTED BY THE AFTERNOON AGAIN. .OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... RESTRICTIONS CAN BE EXPECTED IN WIDESPREAD SHOWERS AND THUNDERSTORMS FRIDAY AND FRIDAY NIGHT...WITH MORE ISOLATED COVERAGE EXPECTED SATURDAY AND SATURDAY NIGHT. SUNDAY SHOULD SEE A RETURN TO VFR CONDITIONS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
246 PM EDT WED AUG 8 2012 .SYNOPSIS... INCREASING HUMIDITY, PLUS A CANADIAN COLD FRONT MOVING SOUTHWARD TOWARD LAKE ERIE, MAY SPARK SCATTERED THUNDERSTORMS THIS AFTERNOON AND EVENING AND AGAIN LATE THURSDAY ACROSS THE UPPER OHIO VALLEY. LOW PRESSURE, COMING EAST FROM MINNESOTA, WILL JOIN THE COLD FRONT AND BRING MORE NUMEROUS SHOWERS AND THUNDERSTORMS FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... RECENT RADAR DATA NOW SHOWS A BAND OF SCATTERED THUNDERSTORMS DEVELOPING ALONG THE LAKE ERIE BREEZE FRONT. WITH SURFACE DEW POINTS HAVING INCREASED INTO THE 60 TO 65 RANGE ACROSS NORTHERN OHIO AND THE PENNSYLVANIA I-80 CORRIDOR, EXPECT THESE STORMS TO EXPAND IN COVERAGE AND MOVE SOUTHEASTWARD INTO EAST CENTRAL OHIO AND WEST CENTRAL PENNSYLVANIA BEFORE 6 PM, A SCENARIO PREDICTED BY RECENT HRRR MODEL OUTPUT. STORM INTENSITY WILL NEED MONITORED AS SPC CONTINUES TO PROJECT SOME SEVERE POTENTIAL. SREF MODEL OUTPUT SUPPORTS THIS IDEA AS IT SHOWS INSTABILITY CAN PEAK ABOVE 1500 J/KG AND VERTICAL WIND SHEAR MAY REACH 30 KTS. FORECASTED HIGH TEMPERATURES IN THE 85 TO 90 RANGE, BUT SUCH HIGHS COULD BE REDUCED IF THUNDERSTORMS PASS THROUGH AN AREA PRIOR TO 5 PM. AFTER DARK, NOCTURNAL COOLING WILL DISSIPATE CONVECTIVE INSTABILITY. PATCHY RIVER VALLEY FOG CAN AGAIN DEVELOP AS IT HAS ON PREVIOUS NIGHTS, AN IDEA SUPPORTED BY RECENT GFS LAMP OUTPUT. FORECASTED LOW TEMPERATURES USING A BLEND OF RECENT NAM AND GFS MOS. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... RECENT SREF MODEL OUTPUT, WITH DETAILS FROM THE NAM, SHOW THE COLD FRONT WILL BECOME STALLED, IN A WEST TO EAST ORIENTATION, ACROSS THE UPPER OHIO VALLEY THURSDAY. EXPECT BANDS OF SCATTERED THUNDERSTORMS TO DEVELOP DAYTIME THURSDAY, DUE TO LOW LEVEL CONVERGENCE IN ADVANCE OF A LOW PRESSURE CENTER COMING EAST FROM MINNESOTA AND IOWA. SPC HAS MAINTAINED A SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON INTO EARLY FRIDAY, WHICH IS SUPPORTED BY SREF MODEL OUTPUT PROJECTIONS OF INSTABILITY, CAPE 2000+ J/KG, AND VERTICAL WIND SHEAR, EFFECTIVE BULK SHEAR 25 KTS. EXPECT SHOWERS AND THUNDERSTORMS TO BE LIKELY FRIDAY DAYTIME AND EARLY EVENING WITH THE NORTHEAST PASSAGE OF THE DEEPENING LOW PRESSURE CENTER. CONCUR WITH HPC THAT WIDESPREAD RAIN AMOUNTS CAN EXCEED 0.50 INCHES, IF NOT 1 INCH. AS THE LOW PRESSURE CENTER MOVES NORTHWARD PAST LAKE ERIE LATE FRIDAY NIGHT AND DAYTIME SATURDAY, EXPECT WRAP-AROUND SHOWERS TO DECREASE IN COVERAGE. DUE TO THE PROSPECTS FOR SHOWERS AND ACCOMPANYING CLOUDINESS, CONCURRED WITH GFS AND NAM MOS IN FORECASTING HIGHS THURSDAY NOT AS WARM AS WEDNESDAY AND THEN COOLER THAN NORMAL FRIDAY. CLOUDS AT NIGHT AND HUMID CONDITIONS WILL KEEP LOWS WARMER THAN NORMAL THURSDAY NIGHT. LOWS FRIDAY NIGHT AND HIGHS SATURDAY CAN BE SLIGHTLY COOLER THAN NORMAL DUE TO COOLER AIR ALOFT. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... WRAPAROUND PRECIPITATION SHOULD BE SHIFTING TO THE NORTHEAST BY SATURDAY NIGHT...AND HAVE REMOVED PRECIPITATION AFTER MIDNIGHT. 00Z GFS SEEMS TO BE AN OUTLIER IN SHOWING DIURNAL PRECIPITATION FOR NEXT WEEK. OTHER MODEL CONSENSUS KEEPS HIGH PRESSURE THROUGH THE PERIOD...AND HAVE STUCK WITH THIS DRY DEPICTION. SUNDAY AND MONDAY SHOULD CONTINUE THE TREND OF SLIGHTLY BELOW NORMAL TEMPERATURES, WITH A SLIGHT RISE IN HIGHS ON TUESDAY. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... WEAK FRONT WILL APPROACH THE REGION AND BECOME STATIONARY OVERNIGHT. THE FRONT OR A LAKE BREEZE BOUNDARY OFF LAKE ERIE COULD SPAWN SOME SCATTERED SHOWERS/THUNDERSTORMS DURING THE AFTERNOON AND EARLY EVENING HOURS. CONFIDENCE IS STILL NOT HIGH ENOUGH IN ANY SINGLE LOCATION TO BE SPECIFIC ABOUT TAF MENTION. OVERNIGHT...ALL GUIDANCE SUGGESTS A DROP TO AT LEAST MVFR VISIBILITY...IF NOT LOWER. ALTHOUGH WINDS SHOULD DROP TO 2-3 KTS OVERNIGHT...THINK THAT THE POSSIBILITY FOR FOG WILL BE DEPENDENT ON WHERE SHOWERS OCCUR DURING THE AFTERNOON. FOR NOW...WILL ADD MVFR VISIBILITIES AND ALLOW LATER TAF ISSUANCES TO DECIDE IF IFR VISIBILITIES ARE REQUIRED IN FORECAST. MID LEVEL CLOUDS WILL MOVE IN ON THURSDAY...WITH SCATTERED SHOWERS/STORMS EXPECTED BY THE AFTERNOON AGAIN. .OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... RESTRICTIONS CAN BE EXPECTED IN WIDESPREAD SHOWERS AND THUNDERSTORMS FRIDAY AND FRIDAY NIGHT...WITH MORE ISOLATED COVERAGE EXPECTED SATURDAY AND SATURDAY NIGHT. SUNDAY SHOULD SEE A RETURN TO VFR CONDITIONS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
543 PM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT WILL MOVE ACROSS OUR AREA BY EARLY THIS EVENING...WITH SCATTERED SHOWERS AND THUNDERSTORMS ACCOMPANYING ITS PASSAGE. MAINLY DRY WEATHER WILL THEN FOLLOW THE FRONT TONIGHT... BEFORE LOW PRESSURE LIFTS NORTHEAST FROM THE OHIO VALLEY THURSDAY AND FRIDAY AND BRINGS INCREASINGLY UNSETTLED CONDITIONS. && .NEAR TERM /THROUGH THURSDAY/... AS OF 2100Z...A SLOW MOVING FRONTAL BOUNDARY WAS JUST SOUTH OF A BUFFALO TO ROCHESTER TO WATERTOWN LINE. THIS CAN BE SEEN BOTH WITH SURFACE OBSERVATIONS...AND THE BOUNDARY SHOWS UP VERY NICELY ON THE MONTAGUE RADAR. THIS FRONT COMBINED WITH LAKE BREEZES HAS SPAWNED SOME SHOWERS AND THUNDERSTORMS OUT AHEAD OF THE BOUNDARY. THE HRRR CAPTURES THIS QUITE WELL...AND SUGGESTS A WEAKENING TREND AS THESE CELLS MOVE TO THE EAST AT ABOUT 20 MPH. GRIDS AND ZONES WERE UPDATED TO REFLECT THE LATEST RADAR TRENDS. FOLLOWING THE PASSAGE OF THE FRONT...THE LOSS OF BOTH LOW LEVEL CONVERGENCE AND DAYTIME HEATING SHOULD BRING AN END TO THE PRECIP DURING THE EARLY TO MID EVENING HOURS...WITH GENERALLY DRY WEATHER THEN EXPECTED TO FOLLOW FOR THE BALANCE OF THE NIGHT. WITH SCATTERED LOWER CLOUDS REMAINING IN PLACE AND MID AND HIGH CLOUDS INCREASING OVERNIGHT IN ADVANCE OF THE NEXT LOW...AT THIS POINT DO NOT EXPECT FOG TO BE A SIGNIFICANT FORECAST CONCERN OVERNIGHT. ON THURSDAY...CLOUDS WILL CONTINUE TO INCREASE AND THICKEN ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST AS UPPER TROUGHING TAKES SHAPE ACROSS THE GREAT LAKES...AND AN ATTENDANT SURFACE LOW DEVELOPS AND LIFTS NORTHEAST ACROSS THE OHIO VALLEY. WITH DIURNAL HEATING...THE FRONTAL BOUNDARY STALLED OUT JUST TO OUR SOUTH MAY BECOME THE FOCUS FOR ANOTHER ROUND OF SCATTERED CONVECTION ACROSS THE SOUTHERN TIER AND FINGER LAKES DURING THE AFTERNOON...BEFORE THE MAIN SURFACE WAVE DRAWS CLOSE ENOUGH TO BRING INCREASING SHOWER/THUNDERSTORM CHANCES TO THE REST OF THE REGION LATER IN THE DAY. WILL CONTINUE TO INDICATE A NORTHEAST-SOUTHWEST GRADIENT IN PRECIP CHANCES ACROSS THE REGION TOMORROW AFTERNOON...RANGING FROM SLIGHT CHANCE/LOW CHANCE ACROSS THE SAINT LAWRENCE VALLEY AND NORTH COUNTRY...TO HIGH CHANCE ACROSS THE SOUTHERN TIER AND FAR WESTERN NEW YORK. WITH THE BEST INSTABILITY REMAINING ALONG AND SOUTH OF THE FRONT AND ANY STRONGER WIND FIELDS ALOFT REMAINING TO ITS NORTH...AT THIS POINT OUR SEVERE WEATHER POTENTIAL FOR TOMORROW AFTERNOON LOOKS TO BE RELATIVELY LOW. AS FOR TEMPERATURES...READINGS WILL AGAIN BE A LITTLE MILDER TONIGHT THAN LAST NIGHT...WITH LOWS RANGING FROM THE UPPER 50S/NEAR 60 ACROSS INTERIOR PORTIONS OF THE SOUTHERN TIER AND NORTH COUNTRY TO THE MID 60S ACROSS THE LAKE PLAINS. WITH 850 MB TEMPS OF +14C TO +16C AND INCREASING CLOUD COVER/PRECIP CHANCES THEN EXPECTED ON THURSDAY...DAYTIME HIGHS SHOULD RANGE FROM THE LOWER TO MID 80S IN MOST LOCATIONS. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... MUCH NEEDED BENEFICIAL RAINS CONTINUING TO LOOK PROMISING DURING THE THURSDAY NIGHT THROUGH FRIDAY NIGHT TIME FRAME...AS POTENT UPPER LEVEL LOW DROPS THROUGH THE GREAT LAKES. NAM/CANADIAN/GFS ALL ON BOARD IN CONTINUING TO DEVELOP INCREASING RAIN AREA...ALONG WITH SOME EMBEDDED STRONGER CONVECTION WITH THE INCREASING MID LEVEL FRONTOGENESIS AND SUBSTANTIAL HEIGHT FALLS TAKING PLACE. PRECIPITATION PATTERN LOOKS TO BECOME EVEN MORE FOCUSED LATE THURSDAY NIGHT AND FRIDAY. THE LOW/MID LEVEL BAROCLINIC ZONE EXTENDING ACROSS NEW YORK STATE WILL UNDERGO SIGNIFICANT FRONTOGENESIS AND DEEPEN IN RESPONSE TO INCREASING UPPER LEVEL DIVERGENCE AND INTENSE LARGE SCALE ASCENT JUST AHEAD OF THE PV ANOMALY...ALLOWING RAIN/EMBEDDED THUNDER TO INCREASE IN COVERAGE/INTENSITY. PLACEMENT OF HEAVIEST PRECIPITATION AXIS WILL BE A TOUGH CALL WITH STILL SOME MODEL DISCREPANCIES IN THE EXACT TRACK OF THE UPPER LEVEL LOW AND SUBSEQUENT SURFACE WAVE...AS WELL AS A MODEL AGREEMENT OF THE PRESENCE OF A SHARP DRY SLOT NOSING INTO A PORTION OF THE AREA. PRECIPITABLE WATER VALUES ACROSS THE ENTIRE AREA WILL BE RUNNING IN THE 1.5 TO 1.75 INCH RANGE. EXPECTATIONS ARE THAT A GENERAL WIDESPREAD 0.75 TO 1.25 INCHES OF RAIN WILL OCCUR...WITH HEAVIER AMOUNTS NEARING 2 INCHES VERY POSSIBLE ACROSS EASTERN SECTIONS OF THE AREA WHERE MODELS DO NOT PLACE ANY SIGNIFICANT DRY SLOTTING. THE STEADIEST PRECIPITATION SHOULD DROP OF FRIDAY NIGHT AND SATURDAY AS DEEP DRY SLOT WORKS INTO THE AREA BEHIND THE LOW AS IT PUSHES INTO ONTARIO. HOWEVER...WRAP AROUND MOISTURE BEGINS TO WORK INTO WESTERN SECTIONS DURING THE DAY SATURDAY...EVENTUALLY PUSHING THROUGH EASTERN SECTIONS BY SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... HEIGHTS BEGIN TO RISE IN THE WAKE OF THE UPPER LOW FOR THE SECOND HALF OF THE WEEKEND. A LINGERING CYCLONIC FLOW OVER EASTERN SECTIONS OF THE AREA COULD TOUCH OFF A FEW SHOWERS...OTHERWISE THE OVERALL TREND IS TO DRY THINGS OUT FROM WEST TO EAST. HEIGHTS CONTINUING TO RISE THROUGH MID WEEK. FOR THE MOST PART EXPECT DRY WEATHER... ALTHOUGH GLOBAL MODELS SUGGESTING A COUPLE OF WEAK SHORT WAVES CROSSING THE REGION IN THE NORTHWEST FLOW ALOFT. HOWEVER...THESE MODELS DIFFER IN INTENSITY AND TRACK OF THE INDIVIDUAL WAVE WAND CONFIDENCE IS LOW THAT MUCH ACTIVITY WILL BE GENERATED...OTHER THAN SOME SPOTTY DIURNALLY DRIVEN CONVECTION. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... AS OF 2100Z...THE SLOW-MOVING COLD FRONTAL BOUNDARY IS DRAPED ACROSS THE LOWER GREAT LAKES AND FAR WESTERN NEW YORK. THE FRONT IS ALREADY THROUGH ALL TAF LOCATIONS...WITH A MINIMAL CHANCE FOR THUNDERSTORMS FOR THE REMAINDER OF THE EVENING. ONCE THE FRONT PASSES THROUGH THE AREA...EXPECT A GRADUAL INCREASE IN MID AND HIGH LEVEL CLOUDINESS EXPECTED OVERNIGHT. COUPLED WITH LINGERING SCATTERED LOWER VFR CLOUDS...THESE SHOULD HELP REDUCE THE RISK OF FOG OVERNIGHT. ON THURSDAY...CLOUD COVER WILL CONTINUE TO THICKEN ACROSS THE AREA THROUGH THE DAY IN ADVANCE OF LOW PRESSURE LIFTING NORTHEAST ACROSS THE OHIO VALLEY. EXPECT THE MORNING TO BE LARGELY DRY...WITH CONVECTIVE CHANCES THEN SLOWLY INCREASING DURING THE AFTERNOON AS THE LOW APPROACHES THE AREA AND DAYTIME INSTABILITY DEVELOPS. AS THE BULK OF ANY PRECIP WILL BE SCATTERED INITIALLY AND SHOULD HOLD OFF UNTIL CLOSE TO OR AFTER 18Z...FOR NOW HAVE ELECTED TO LEAVE THE TAFS DRY LATE IN THE PERIOD. OUTLOOK... THURSDAY NIGHT AND FRIDAY...IFR/MVFR IN RAIN WITH SCATTERED THUNDERSTORMS. SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. SUNDAY...MAINLY VFR. MONDAY...VFR. && .MARINE... A WEAK COLD FRONT WILL MOVE FINISH CROSSING THE LOWER LAKES BY EARLY THIS EVENING... WITH SCATTERED SHOWERS AND THUNDERSTORMS ACCOMPANYING ITS PASSAGE. MAINLY DRY WEATHER WILL THEN FOLLOW THE FRONT TONIGHT...BEFORE LOW PRESSURE LIFTS NORTHEAST FROM THE OHIO VALLEY THURSDAY AND FRIDAY AND BRINGS INCREASINGLY UNSETTLED CONDITIONS...INCLUDING THE THREAT OF SCATTERED THUNDERSTORMS. IN TERMS OF WINDS AND WAVES...GENERALLY LIGHT TO MODEST WINDS TO CONTINUE THROUGH THURSDAY...WITH WAVES REMAINING UNDER 2 FEET. AFTER THAT TIME...A STRENGTHENING NORTH TO NORTHEASTERLY FLOW WILL BRING A RISK OF ADVISORY LEVEL WINDS AND WAVES TO WESTERN LAKE ONTARIO BY FRIDAY MORNING. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...JJR NEAR TERM...APFFEL/JJR SHORT TERM...TMA LONG TERM...TMA AVIATION...JJR MARINE...JJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
610 PM EDT WED AUG 8 2012 .SYNOPSIS... SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE EVENING. ONLY WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THURSDAY WITH BETTER CHANCES EXPECTED FRIDAY. A COLD FRONT WILL ALLOW THE CHANCE OF STORMS TO CONTINUE ON SATURDAY. HIGH PRESSURE WILL BUILD INTO THE AREA EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 6:00 PM WEDNESDAY...HAVE FIRED OUT A QUICK UPDATE TO GO WITH CATEGORICAL POPS FOR NORTHWESTERN COUNTIES AS CONVECTION APPEARS TO BE ORGANIZING. HRRR HAS THE ACTIVITY CAPTURED WELL AND MAINTAINS IT FOR SEVERAL HOURS. DAYTIME HEATING HAS ALLOWED THE TEMPERATURES TO RISE TO THE UPPER 80S IN THESE AREAS PROVIDING AMPLE SURFACE BASED INSTABILITY. HRRR/1800 UTC GFS AND NAM SHOW THIS WILL BE ALL THE ACTIVITY AND THEREFORE REMOVED POPS FOR THE REMAINDER OF THE AREA AFTER AROUND 0400 UTC. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...THE NEXT H5 TROUGH WILL DEVELOP ACROSS THE MS VALLEY THU AS AN UPPER LOW DIVES SOUTH FROM THE WESTERN GREAT LAKES REGION. THE RESULT WILL BE A HIGHLY AMPLIFIED/ANOMALOUS TROUGH ALOFT OVER THE EASTERN UNITED STATES BY FRIDAY. THE TROUGH WILL PUSH A COLD FRONT TOWARD THE FORECAST AREA LATE FRIDAY. THE PRECIPITABLE WATER WILL ALSO INCREASE TO 2+INCHES FRIDAY AHEAD OF THE FRONT ALONG WITH SUFFICIENT INSTABILITY THE BETTER BET FOR TSTMS DURING THE SHORT TERM PERIOD WILL BE FRIDAY. CURRENTLY THE FORECAST AREA IS IN A SLIGHT RISK FOR SEVERE TSTMS FRIDAY...BUT ULTIMATELY IT MAY DEPEND ON THE AMOUNT OF CLOUD COVER WHICH COULD IMPEDE DESTABILIZATION. OTHERWISE...FAVORED A BLEND OF MAV/MET NUMBERS EACH PERIOD. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 3 PM WEDNESDAY...IN A PATTERN MORE COMMONLY SEEN IN NOVEMBER THAN MID-AUGUST...A HIGHLY ANOMALOUS 500MB TROUGH SPINS ACROSS THE GREAT LAKES BEFORE ROTATING OFF TO THE NORTHEAST DURING THE EARLY PART OF THE WEEK. AS THIS TROUGH SLOWLY SPINS AWAY...IT DRAGS A COLD FRONT ACROSS THE AREA. GUIDANCE IN DECENT AGREEMENT ON TIMING OF THIS FRONT...AND EXPECT FROPA TO OCCUR VERY EARLY SUNDAY. MOST SIGNIFICANT WEATHER OF THE EXTENDED WILL OCCUR SATURDAY AS FRONT PUSHES ACROSS THE AREA...DISPLACING THE WARM SECTOR AIRMASS. ATTM SPC HAS NO PORTION OF OUR REGION OUTLOOKED IN DAY 4...BUT WOULD NOT BE SURPRISED IF A SLIGHT RISK OR SEE TEXT IS INTRODUCED WITH LATER UPDATES AS FRONT WORKS INTO A MODERATELY UNSTABLE AIRMASS WITH DECENT NEARLY UNIDIRECTIONAL SHEAR AND HIGH PWATS. ADDITIONALLY...GFS/EURO SHOW STRONG PVA ASSOCIATED WITH A VORT LOBE ALONG THE FRONT AND DIFFLUENCE IN THE RIGHT ENTRANCE REGION TO A 90KT 300MB JET. ALL THESE TOGETHER SUGGEST SCATTERED TO WIDESPREAD THUNDERSTORMS SATURDAY...WITH THE POTENTIAL FOR ISOLATED DAMAGING WIND GUSTS. THE LIMITING FACTOR MAY BE INCREASED CLOUD COVER FROM CONVECTIVE DEBRIS FRIDAY...BUT THIS IS STILL YET TO BE SEEN. WILL KEEP INHERITED LIKELY POP SATURDAY...WANING TO SCHC BY SUNDAY MORNING AS FRONT MOVES OFFSHORE. TEMPS SATURDAY WILL BE RIGHT AROUND CLIMO...90/70. DRIER AIR BEHIND THE FRONT COMBINED WITH SLIGHTLY INCREASED 500MB HEIGHTS WILL CAUSE A SIGNIFICANT DECREASE IN TSTM CHANCES SUN-TUE. STILL...WITH TEMPS AROUND 90 AND SLIGHTLY ENHANCED LAPSE RATES DUE TO BROAD EAST-COAST TROUGHING...ANY DAY COULD FEATURE ISOLATED DIURNAL CONVECTION. WILL KEEP POP BELOW MENTIONABLE SUN/MON BEFORE MOISTURE RETURN INCREASES WITH RETURN OF BERMUDA HIGH TUE/WED. TEMPS THROUGH THE WEEK WILL BE NEAR NORMAL FOR MID AUGUST. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...SOME LIGHT SHOWERS WILL PERSISTS FOR THE FIRST COUPLE OF HOURS ALONG THE COAST. THEY SHOULD HAVE LITTLE AVIATION IMPACT. LOOK FOR VFR CONDITIONS THROUGH THE AFTERNOON HOURS...WITH ISOLATED SHOWERS POSSIBLE. LIGHT WINDS TONIGHT WITH SCATTERING SKIES. GIVEN THOSE CONDITIONS...ALONG WITH GOOD LOW LEVEL MOISTURE...EXPECT IFR FOG TO EMERGE AFTER 08Z. IT IS POSSIBLE IT COULD BECOME DENSE...BUT WILL STAY WITH IFR AT THIS TIME. THURSDAY...MORNING FOG SHOULD MIX OUT BY 13Z WITH VFR CONDITIONS EXPECTED. LIGHT NORTHWEST FLOW BEHIND THE DEEP MOISTURE EXITING THE REGION. EXTENDED OUTLOOK...CHANCE OF MORNING MVFR VSBYS IN BR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 6:00 PM WEDNESDAY...NO CHANGES TO COASTAL WATERS FORECAST WITH THE EVENING UPDATE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...LIGHT WESTERLY FLOW THURSDAY MORNING WILL BACK TO A SOUTHERLY DIRECTION DURING THE DAY AND INCREASE INTO THE 10-15 KT RANGE. SOUTH TO SOUTHWEST FLOW WILL PREVAIL THURSDAY NIGHT AND LINGER AROUND 15 KT FRIDAY. SPEEDS COULD REACH 15-20 KT FRIDAY NIGHT AHEAD OF A COLD FRONT. THE SOUTH TO SOUTHWEST FETCH WILL ALLOW SEAS TO BUILD TO EXERCISE CAUTION LEVELS DURING THE PERIOD...AND WILL BE HIGHEST DURING FRIDAY NIGHT LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 3 PM WEDNESDAY...SW FLOW THROUGH THE PERIOD...BUT WILL BE STRONGEST SATURDAY AS COLD FRONT APPROACHES FROM THE WEST. AS THIS FRONT WORKS TOWARDS THE COAST...PRESSURE GRADIENT TIGHTENS...AND WINDS WILL BE AROUND 15 KTS SATURDAY. GRADIENT WILL EASE AS FRONT MOVES TO THE WATERS AND DISSIPATES BY EARLY SUNDAY...BECOMING 10 KTS OR LESS SUNDAY AND MONDAY...STILL FROM THE SW. A WEAK SE SWELL WILL EXIST THROUGH THE EXTENDED...BUT SIGNIFICANT WAVE HEIGHTS WILL BE DRIVEN ALMOST EXCLUSIVELY BY THE WIND. 3-5 FT SEAS SATURDAY WILL DECREASE THROUGH SUNDAY...BECOMING 2-3 FT LATE SUNDAY AND MONDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...15 SHORT TERM...SRP LONG TERM...JDW AVIATION...DL/HAWKINS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
431 PM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT WILL REMAIN NEARLY STATIONARY ALONG THE OHIO RIVER TONIGHT INTO THURSDAY. A STRONGER COLD FRONT AHEAD OF AN ENERGETIC UPPER LEVEL LOW WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO THE OHIO VALLEY ON THURSDAY NIGHT AND FRIDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... A WEAK COLD FRONT HAD DROPPED SOUTH INTO NORTHERN OHIO AND INDIANA LATE THIS AFTERNOON. THIS AFTERNOON...WIDELY SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS HAD DEVELOPED ALONG AND AHEAD OF THE COLD FRONT DUE TO WEAK LOW LEVEL FORCING AND HOT AFTERNOON TEMPERATURES. THIS FRONT WILL CONTINUE TO DROP SOUTH TONIGHT AND BECOME NEARLY STATIONARY NEAR THE OHIO RIVER. THE SHOWER AND THUNDERSTORM ACTIVITY WILL DECREASE THROUGH THE LATE EVENING HOURS. ANOTHER CHANCE OF SHOWERS/THUNDERSTORMS WILL OCCUR IN THE EARLY MORNING HOURS WITH AN UPPER LEVEL SYSTEM. WITH HIGH INSTABILITY ACROSS THE REGION THROUGH THIS EVENING...CAN NOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM. DAMAGING WINDS AND LARGE HAIL WOULD BE THE MAIN THREATS. THE LOWS TONIGHT WILL BE WARMER THAN WEDNESDAY NIGHT WITH LOWS IN THE MID 60S TO AROUND 70. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... THE WEAK COLD FRONT WILL LAY OUT AS A BOUNDARY ON THURSDAY AND ANOTHER MID LEVEL SHORTWAVE WILL INTERACT WITH IT. THIS WILL BRING A BETTER CHANCE OF THUNDERSTORMS ACROSS THE FORECAST AREA. WILL ALSO SEE A CHANCE OF SEVERE WEATHER WITH THE MAIN THREAT BEING DAMAGING WINDS. LOW PRESSURE WILL RIDE NE ALONG THE BOUNDARY THURSDAY NIGHT IN RESPONSE TO AN UPPER LOW STRENGTHENING OVER THE WESTERN GREAT LAKES AND CROSSING THE NORTHERN OHIO VALLEY BY EARLY FRI. MODELS HANDLE THE TRACK OF THE LOW A LITTLE DIFFERENTLY WHICH WILL IMPACT WHERE GREATEST PRECIPITATION OCCURRS. THE BEST COVERAGE OF SHOWERS/THUNDERSTORMS WILL BE LATE THURSDAY INTO FRIDAY AS THE LOW APPROACHES AND MOVES THROUGH THE OHIO VALLEY REGION. WITH AN INCREASE IN CLOUDS AND PRECIPITATION THURSDAY...THE HIGH TEMEPRATURES WILL BE COOLER THAN TODAY. MOST AREAS WILL SEE HIGHS IN THE 80S EXCEPT AROUND 90 IN THE FAR SE. THE LOWS THURSDAY NIGHT WILL BE IN THE 60S. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... CLOSED UPPER LOW PROGGED TO BE OVER LOWER MICHIGAN AT 12Z FRIDAY WITH SURFACE LOW POSITIONED OVER LAKE ERIE. THIS SYSTEM WILL GRADUALLY PUSH FURTHER NORTHEASTWARD INTO CANADA THROUGH THE FIRST PART OF THE WEEKEND...LEAVING MAINLY DRY AND COOLER CONDITIONS IN ITS WAKE. WENT ON THE COOL SIDE OF GUIDANCE FOR FRIDAY AS CLOUDS... PRECIPITATION...AND NORTHERLY FLOW BEHIND A FRONTAL BOUNDARY WILL KEEP TEMPERATURES DOWN. FORECASTED HIGHS FOR FRIDAY RIGHT NOW ARE ABOUT 10 DEGREES BELOW NORMAL. BOTH THE 00Z AND 12Z ECMWF RUNS HAVE BEEN A LITTLE QUICKER TO PUSH THE SYSTEM OUT OF THE AREA THAN THE LATEST NAM/GFS...SO DECIDED TO KEEP JUST SLIGHT POPS INTO SATURDAY FOR THE FAR NORTHEASTERN CWA. EXPECT A GRADUAL CLEARING SATURDAY AFTERNOON INTO THE OVERNIGHT AS THE LOW PUSHES AWAY. LOWS SATURDAY NIGHT WILL BE COOL AS HIGH PRESSURE BUILDS INTO THE REGION. WINDS WILL BECOME MORE SOUTHERLY BY SUNDAY THE HIGH DRIFTS EAST OF THE REGION. THIS WILL BE THE START OF A WARMING TREND THAT WILL CONTINUE THROUGH THE FIRST PART OF NEXT WEEK WITH TEMPERATURES BACK IN THE 80S. ONLY OTHER FEATURES OF CONCERN FOR THE EXTENDED PERIOD WILL ARRIVE MONDAY INTO MONDAY NIGHT AS THE GFS BRINGS A DECENT SHORTWAVE AND SURFACE LOW THROUGH THE REGION. NEITHER FEATURE HAS BEEN QUITE AS DEVELOPED IN THE PAST TWO ECMWF RUNS AND THUS THE ECMWF HAS BEEN TRENDING DRY. WENT AHEAD AND INTRODUCED SLIGHT POPS FOR THIS PERIOD AS THE PAST FEW GFS RUNS HAVE BEEN CONSISTENT AND THE FEATURES ARE AT LEAST EVIDENT IN THE ECMWF...BUT CONFIDENCE IN PRECIP IS NOT VERY HIGH AT THIS TIME. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... CU FIELD IS TRYING TO FILL IN ACROSS THE AREA EARLY THIS AFTERNOON AS WE CONTINUE TO WARM UP AND DESTABILIZE. ML CAPES ARE NOW INTO THE 1500 TO 2000 J/KG RANGE ACROSS MUCH OF THE REGION. AS THE COLD FRONT SAGS SLOWLY SOUTH ACROSS THE REGION THROUGH THIS EVENING...A FEW THUNDERSTORMS MAY POP UP GIVEN THE INSTABILITY AND WEAK LOW LEVEL FORCING. MEANWHILE...REMNANTS FROM EARLIER CONVECTION ARE CONTINUING TO PROGRESS ACROSS ILLINOIS TOWARD WESTERN INDIANA. THE LAST FEW RUNS OF THE RAP HAVE BEEN TRYING TO PIVOT A WEAKENING LINE OF SHOWERS ASSOCIATED WITH THIS UP ACROSS AT LEAST OUR WESTERN AREAS THROUGH EARLY EVENING. GIVEN THE UNCERTAINTY...THINK THE BEST WAY TO COVER THE CHANCE RIGHT NOW IS JUST WITH A VCSH. ANOTHER WEAK MID LEVEL SHORT WAVE WILL THEN PUSH TOWARD THE AREA LATE TONIGHT INTO THURSDAY MORNING. EXPECT THE BEST CHANCE FOR ANY PCPN ASSOCIATED WITH THIS TO BE ACROSS OUR NORTH AND WILL AGAIN COVER WITH A VCSH. A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP OFF TO OUR WEST THROUGH THE AFTERNOON HOURS...POSSIBLY AFFECTING CVG TOWARD THE END OF THEIR TAF PERIOD. .OUTLOOK...THUNDERSTORMS ARE POSSIBLE INTO FRIDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...PARKER NEAR TERM...PARKER SHORT TERM...PARKER LONG TERM...KURZ AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
154 PM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT WILL CROSS THE REGION TODAY. THIS FRONT WILL REMAIN NEARLY STATIONARY ALONG THE OHIO RIVER TONIGHT INTO THURSDAY. A STRONGER COLD FRONT AHEAD OF AN ENERGETIC UPPER LEVEL LOW WILL BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO THE OHIO VALLEY ON THURSDAY NIGHT AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOOKS LIKE MAYBE A FEW AC UP ACROSS OUR NORTH BUT FOR THE MOST PART...SKIES ARE MOSTLY CLEAR THIS MORNING. A WEAK COLD FRONT CURRENTLY ACROSS FAR NORTHERN INDIANA AND OHIO...WILL SAG SOUTH INTO OUR AREA THROUGH THIS AFTERNOON. AHEAD OF THE FRONT...WE SHOULD SEE A DECENT WARM UP THROUGH THIS AFTERNOON. TEMPS ARE CURRENTLY RUNNING SEVERAL DEGREES AHEAD OF YESTERDAY AND THE 12Z ILN SOUNDING IS 19 DEGREES AT 850 MB...WHICH IS 3 DEGREES WARMER THAN TUESDAY MORNING. AS A RESULT...EXPECT TEMPERATURES 4 TO MAYBE EVEN 5 DEGREES WARMER THAN WHAT SAW YESTERDAY AFTERNOON...ESPECIALLY ACROSS SOUTHERN PORTIONS OF OUR AREA WHERE BEST LOW LEVEL WAA SHOULD EXIST AHEAD OF THE FRONT. WILL GENERALLY HAVE HIGHS IN THE LOW TO MID 90S. CVG DID GET TO 95 DEGREES YESTERDAY...SO A FEW UPPER 90S ARE NOT OUT OF THE QUESTION ACROSS OUR SOUTHWEST. THE RECORD FOR CVG IS 100 DEGREES AND CMH IS 96...SO WE MAY NOT BE TOO FAR OFF FROM THOSE NUMBERS. MEANWHILE AS WE DESTABILIZE THROUGH THIS AFTERNOON...TOUGH TO RULE OUT A FEW THUNDERSTORMS GIVEN WEAK LOW LEVEL FORCING ALONG THE FRONT. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... THE WEAK COLD FRONT WILL LAY OUT AS A BOUNDARY ON THURSDAY AND ANOTHER MID LEVEL SHORTWAVE WILL INTERACT WITH IT AND STAND A BETTER CHANCE OF POPPING SOME THUNDERSTORMS OVER THE AREA. THE BOUNDARY WILL SEE LOW PRESSURE RIDE NORTHEAST ALONG IT THURSDAY NIGHT IN RESPONSE TO AN UPPER LOW STRENGTHENING OVER THE WESTERN GREAT LAKES AND CROSSING THE NORTHERN OHIO VALLEY BY EARLY FRIDAY. THE SHOWERS AND THUNDERSTORMS THAT DEVELOP THURSDAY NIGHT IN RESPONSE TO THESE FEATURES WILL BECOME MORE AND MORE LIKELY AS TIME PROGRESSES. TEMPERATURES ON FRIDAY WILL BE MARKEDLY COOLER...UPPER 60S TO LOWER 70S IN A COLD ADVECTION PATTERN AND NOTABLY WETTER IN THE POST-FRONTAL WRAP AROUND MOISTURE. SIGNIFICANTLY COOLER AIR WILL BE OVER THE REGION THIS WEEKEND AS A CUTOFF LOW PROVIDES FOR CLOUDY SKIES AND A CONTINUED COLD PUSH ON NORTHERLY WINDS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... FOR SATURDAY INTO SATURDAY NIGHT...A QUICKER UPR LVL LOW MOTION TO THE NE WAS USED BUT MAY END UP BEING SLOWER THAN CURRENTLY FORECAST DUE TO RECENT MODEL GUIDANCE. HAVE A CHANCE OF SHOWERS DIMINISHING WEST TO EAST THROUGH THIS PERIOD ALONG WITH GRADUAL CLEARING SATURDAY INTO SATURDAY NIGHT. TEMPERATURES ON SATURDAY WILL BE CLOUD DEPENDENT AND HAVE GONE WITH HIGHS IN THE MID TO UPPER 70S. LOWS SATURDAY NIGHT WILL BE COOL AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. FOR THE REMAINDER OF THE EXTENDED...SUNDAY THROUGH TUESDAY...THE GREAT LAKES AND OHIO VALLEY AREA WILL BE UNDER A NORTHWEST FLOW PATTERN ALOFT. THERE ARE INDICATIONS THAT A FEW WEAK DISTURBANCES WILL RIPPLE SE WITHIN THIS FLOW...BRINGING A SMALL THREAT FOR PCPN. GIVEN THAT THEY APPEAR WEAK ATTM AND TIMING IS DIFFICULT AT BEST AT THIS JUNCTURE...HAVE MAINTAINED A DRY FORECAST ALONG WITH MODIFYING TEMPERATURES AS HEIGHTS AND TEMPERATURES ALOFT RISE THROUGH THE PERIOD. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... CU FIELD IS TRYING TO FILL IN ACROSS THE AREA EARLY THIS AFTERNOON AS WE CONTINUE TO WARM UP AND DESTABILIZE. ML CAPES ARE NOW INTO THE 1500 TO 2000 J/KG RANGE ACROSS MUCH OF THE REGION. AS THE COLD FRONT SAGS SLOWLY SOUTH ACROSS THE REGION THROUGH THIS EVENING...A FEW THUNDERSTORMS MAY POP UP GIVEN THE INSTABILITY AND WEAK LOW LEVEL FORCING. MEANWHILE...REMNANTS FROM EARLIER CONVECTION ARE CONTINUING TO PROGRESS ACROSS ILLINOIS TOWARD WESTERN INDIANA. THE LAST FEW RUNS OF THE RAP HAVE BEEN TRYING TO PIVOT A WEAKENING LINE OF SHOWERS ASSOCIATED WITH THIS UP ACROSS AT LEAST OUR WESTERN AREAS THROUGH EARLY EVENING. GIVEN THE UNCERTAINTY...THINK THE BEST WAY TO COVER THE CHANCE RIGHT NOW IS JUST WITH A VCSH. ANOTHER WEAK MID LEVEL SHORT WAVE WILL THEN PUSH TOWARD THE AREA LATE TONIGHT INTO THURSDAY MORNING. EXPECT THE BEST CHANCE FOR ANY PCPN ASSOCIATED WITH THIS TO BE ACROSS OUR NORTH AND WILL AGAIN COVER WITH A VCSH. A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP OFF TO OUR WEST THROUGH THE AFTERNOON HOURS...POSSIBLY AFFECTING CVG TOWARD THE END OF THEIR TAF PERIOD. .OUTLOOK...THUNDERSTORMS ARE POSSIBLE INTO FRIDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...FRANKS NEAR TERM...JGL SHORT TERM...FRANKS LONG TERM...HICKMAN AVIATION...JGL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
120 PM EDT WED AUG 8 2012 .SYNOPSIS... A WEAK COLD FRONT JUST NORTH OF LAKE ERIE WILL MOVE SOUTHEAST ACROSS THE LOCAL AREA TODAY AND THEN STALL NEAR THE OHIO RIVER. LOW PRESSURE WILL MOVE UP THE OHIO VALLEY THURSDAY AND FRIDAY. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION FROM THE WEST OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD FRONT FROM JUST NORTH OF BUF TO JUST SOUTH OF TOL. FORECAST LOOKS REASONABLE. MADE MINOR ADJUSTMENTS TO THE TIMING OF THE CLOUD COVER FOR UPDATE. PREVIOUS...THE COLD FRONT IS ON TRACK TO MOVE SE ACROSS THE AREA TODAY. SOME SHOWERS AND EVEN SOME LIGHTNING OCCURRED EARLIER IN THE NIGHT ALONG THE FRONT ACROSS LOWER MICHIGAN. LATEST HRRR AND CONVECTIVE SREF CONTINUE TO SUGGEST THAT ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP ALONG THE FRONT LATER TODAY. BEST CHANCES FOR THIS WILL BE IN THE EAST THIS AFTERNOON. HAVE GONE WITH A 20 TO 30 POP MOST AREAS. CLOUDS WILL COME AND GO TODAY BUT BY LATE AFTERNOON SKIES SHOULD BE MAINLY PARTLY CLOUDY. HIGH TEMPS WILL BE A DEGREE OR TWO COOLER THAN TUESDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ACTIVE WEATHER IS EXPECTED DURING THE PERIOD AS AN UPPER LOW GETS SET UP OVER THE EASTERN CONUS. THE MODELS NOW ARE FAIRLY SIMILAR WITH THE MAIN FEATURES. LOW PRESSURE IS EXPECTED TO MOVE UP THE OHIO VALLEY TONIGHT AND FRIDAY WITH THE LOW EVENTUALLY CROSSING WESTERN PA. MODELS SHOWING GOOD ISENTROPIC LIFT WITH PWAT VALUES EVENTUALLY REACHING 1.75 INCHES. INSTABILITY WILL INCREASE TONIGHT AND THURSDAY AS DEWPOINTS SURGE INTO THE UPPER 60S. A FEW STRONG TO SEVERE STORMS ARE LIKELY LATE THURSDAY AS THE LOW PASSES. SHEAR WILL BE ENHANCED ALONG THE FRONT STRETCHING NE FROM THE LOW. THAT IS LIKELY WHERE ANY SEVERE WEATHER WILL OCCUR. WRAP AROUND MOISTURE BEHIND THE LOW WILL KEEP SHOWERS GOING THROUGH MIDDAY SATURDAY ALL AREAS AND IN THE EAST ON SATURDAY NIGHT. 850 MB TEMPS DIP TO PLUS 8 OR 10 SATURDAY DEPENDING ON WHICH MODEL YOU BELIEVE. EITHER WAY COLD AIR ADVECTION CLOUDS AND SHOWERS WILL BE LIKELY TO THE EAST OF KCLE. EXPECT MUCH OF THE AREA TO SEE AN INCH OR MORE OR RAIN THURSDAY THROUGH FRIDAY. TEMPS DURING THE PERIOD WILL BE BELOW NORMAL FOR A CHANGE. && .LONG TERM /SUNDAY THROUGH TUESDAY/... MODELS CONTINUING TO HANDLE STRONG UPPER TROUGH OVER THE AREA WELL WITH GFS AND ECMWF MOVING IT OFF TO THE EAST ON SUNDAY WITH SFC HIGH PRESSURE BUILDING INTO THE AREA. GOING INTO EARLY NEXT WEEK MADE LITTLE CHANGES OVERALL TO THE FORECAST WITH 00Z ECMWF SHOWING BROAD UPPER TROUGH MOVING ACROSS THE AREA WHILE GFS ALSO BRINGING UPPER TROUGH OVER THE AREA BUT A BIT STRONGER WITH SFC LOW PRESSURE DEVELOPING OVER THE MID MISSISSIPPI VALLEY. FOR NOW WILL CONTINUE TO LEAN TOWARD THE ECMWF WITH MAINLY DRY CONDITIONS...BUT HAVE CONTINUE WITH MORE CLOUDINESS ACROSS THE AREA DURING THIS TIME. WITH NO STRONG TEMP ADVECTION MODERATED TEMPS FOR SUNDAY WITH THE TROUGH DEPARTING BUT OTHERWISE KEPT THEM NEAR NORMAL FOR EARLY NEXT WEEK. && .AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... A WEAK COLD FRONT WILL BECOME STATIONARY OVER THE CENTRAL PORTION OF OHIO THIS EVENING. THIS BOUNDARY MAY CAUSE ENOUGH LOW LEVEL CONVERGENCE TO CAUSE A COUPLE THUNDERSTORMS TO DEVELOP OVER NE OHIO INTO NW PA. ONLY HAVE MENTIONED VICINITY THUNDER FOR THE KYNG TAF AT THIS TIME. HOWEVER WILL WATCH INLAND LOCATIONS FURTHER WEST THROUGH THE AFTERNOON. UNCERTAINTY AS WE APPROACH SUNRISE IS THE AMOUNT OF MVFR FOG THAT CAN DEVELOP WITH THE OVERALL INCREASE IN LIFT AS THE UPPER LEVEL TROUGH ARRIVES. AT THIS POINT DID NOT INTRODUCE ANY INTO THE TAF SITES BUT IF IT CAN OCCUR IT MAY BE ACROSS THE WESTERN TAF SITES. BELIEVE THERE WILL ALSO BE SOME SHOWERS THAT DRIFT INTO THE WEST ABOUT THE SAME TIME AS THE MVFR VISIBILITIES. SO FAR HAVE ONLY INTRODUCED A VICINITY SHOWER WITH UNCERTAINTY ON HOW FAST IT WILL MOVE INTO NW OHIO. THERE WILL EVENTUALLY BE A THREAT OF THUNDERSTORMS AS WE HEAT THE SURFACE INTO THE EARLY AFTERNOON. .OUTLOOK...PERIODS OF NON VFR POSSIBLE THURSDAY AND FRIDAY. NON VFR POSSIBLE SATURDAY ACROSS NE OHIO INTO NW PA. && .MARINE... A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TODAY BUT SHOULD CAUSE ANY SIGNIFICANT WEATHER OTHER THAN THE WIND SHIFT FROM SOUTHWEST TO NORTH TONIGHT. THE SIGNIFICANT WEATHER ISSUE FOR THE LAKE WILL BEGIN THURSDAY AS A STRONG UPPER TROUGH MOVES TOWARD THE LAKE AND SFC LOW PRESSURE INTENSIFIES OVER THE OHIO VALLEY...THEN MOVES TO THE NORTHEAST FRIDAY. NORTHEAST FLOW WILL INCREASE THROUGH THURSDAY WITH WINDS RANGING 20 KNOTS OR GREATER BY THURSDAY NIGHT AND CONTINUING THROUGH FRIDAY NIGHT. WINDS WILL SLOWLY DIMINISH THROUGH SATURDAY. HIGH PRESSURE WILL BUILD OVER THE LAKE ON SUNDAY. SMALL CRAFT ADVISORY CONDITIONS APPEAR LIKELY BEGINNING THURSDAY NIGHT AND CONTINUING THROUGH AT LEAST SATURDAY MORNING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...DJB/KUBINA SHORT TERM...KUBINA LONG TERM...ABE AVIATION...MULLEN MARINE...ABE
AREA FORECAST DISCUSSION
NWS TULSA OK
343 PM CDT WED AUG 8 2012 .DISCUSSION... ONGOING CONVECTION WILL MAINTAIN A RISK OF DAMAGING DOWNBURST WINDS ACROSS SE OK AND WESTERN AR INTO SUNSET...WITH ATTENTION THEN TURNING TO EXPANDING CONVECTION ACROSS THE CENTRAL PLAINS. THIS CONVECTION WILL BE FORCED BY A RESPECTABLE MID LEVEL WAVE FOR EARLY AUGUST...AND LIKELY DEVELOP SOUTH AND EASTWARD AFTER SUNSET. GIVEN THE DEEPLY MIXED AND NOT-YET OVERTURNED BOUNDARY LAYER IN PLACE ACROSS NE OK...THE CONVECTION WILL HAVE A GOOD CHANCE OF DEVELOPING INTO THE REGION. THE SOUTHWARD EXTENT SHOULD BE LIMITED BY THE ONGOING CONVECTION AND ITS EFFECTS ON STABILIZING THE BOUNDARY LAYER. THIS SCENARIO IS LARGELY SUPPORTED BY THE 18Z NAM AND HRRR OUTPUT. THE COLD FRONT ASSOCIATED WITH THE PASSING WAVE WILL MOVE INTO NE OK BY SUNRISE THURSDAY...AND THROUGH MUCH OF THE FORECAST AREA BY SUNSET THURSDAY. STORM CHANCES WILL RESIDE ALONG AND SOUTH OF THE BOUNDARY PRIMARILY DURING THE AFTERNOON HOURS ON THURSDAY. NOTICEABLY DRIER AND COOLER AIR WILL FOLLOW THE FRONT AND BRING TEMPS NEAR NORMAL FRIDAY AND SATURDAY. RAINFALL FOOTPRINTS...OR LACK THEREOF...MAY LARGELY AFFECT THE DEGREE OF COOLING GIVEN THE VERY WARM GROUND TEMPS AND LACK OF CLOUD COVER BEHIND THE FRONT. UPPER RIDGING WILL ATTEMPT TO EXPAND BACK EASTWARD OVER THE WEEKEND...THOUGH IT LOOKS TO BE SUPPRESSED FURTHER SOUTH AND NOT HAVE AS STRONG AS INFLUENCE AS RECENTLY. SOUTHERN PERIPHERY OF A PASSING WAVE MAY SUPPORT PRECIP LATE SUNDAY INTO MONDAY...OTHERWISE NO SIGNIFICANT PRECIP CHANCES ARE NOTED UNTIL POSSIBLY JUST BEYOND THIS FORECAST TIME FRAME. && .PRELIMINARY POINT TEMPS/POPS... TUL 75 100 69 92 / 30 0 10 0 FSM 78 104 70 93 / 30 20 10 0 MLC 74 103 69 94 / 30 20 10 0 BVO 69 99 64 92 / 30 0 10 0 FYV 67 97 64 87 / 40 10 10 0 BYV 70 95 66 85 / 50 10 10 0 MKO 73 102 69 93 / 40 0 10 0 MIO 71 97 68 88 / 40 0 10 0 F10 75 102 70 93 / 30 10 10 0 HHW 75 103 73 95 / 30 30 10 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ LONG TERM....07
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
359 PM CDT WED AUG 8 2012 .SHORT TERM... SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE HEARTLAND AND CONCHO VALLEY THIS AFTERNOON. THIS ACTIVITY IS DEVELOPING IN ASSOCIATION WITH LIFT FROM A WEAK SHORT WAVE THAT IS OVERSPREADING THE AREA FROM THE NORTH. LATEST HRRR SEEMS TO BE DOING A DECENT JOB SO FAR AND INDICATES ADDITIONAL DEVELOPMENT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA THROUGH EARLY EVENING. WILL MAINTAIN 30 POPS SOUTH AND SLIGHT CHANCE POPS NORTH ACROSS THE BIG COUNTRY THROUGH THE EVENING HOURS. MAY STILL SEE SOME LINGERING ACTIVITY ALONG THE I-10 CORRIDOR THROUGH LATE EVENING BUT MOST OF THE CONVECTION SHOULD DISSIPATE AFTER SUNEST. THE MAIN THREAT FROM THUNDERSTORMS WILL BE LOCALLY HEAVY RAINFALL...GUSTY WINDS AND DANGEROUS CLOUD TO GROUND LIGHTNING. DRIER AIR WILL FILTER INTO THE AREA FROM THE NORTH LATER TONIGHT AND THURSDAY. THIS WILL RESULT IN DRY AND HOT CONDITIONS ACROSS THE AREA WITH AFTERNOON HIGHS AROUND THE CENTURY MARK. CANNOT RULE OUT AN ISOLATED STORM OR TWO ACROSS SOUTHEAST SECTIONS THURSDAY AFTERNOON SO KEPT ISOLATED MENTION OVER THIS AREA. .LONG TERM... AS AN UPPER TROUGH AND LOW DROP SOUTHEAST ACROSS THE LOWER GREAT LAKES REGION...TRAILING PORTION OF ASSOCIATED COLD FRONT WILL MOVE SOUTH INTO THE BIG COUNTRY THURSDAY NIGHT... AND ACROSS THE REST OF WEST CENTRAL TEXAS ON FRIDAY. THIS PORTION OF THE FRONT WILL BE WEAK HOWEVER...WITH THE MAIN ADVECTION OF COOLER AIR EXPECTED TO BE TO THE NORTHEAST OF OUR AREA. WITH WEAK SURFACE CONVERGENCE AND A DRIER AIRMASS PROGGED...RAIN CHANCES LOOK LOOK TOO SMALL INCLUDE IN OUR AREA WITH THE ARRIVAL/PASSAGE OF THIS FRONT. TEMPERATURES WILL BE SLIGHTLY COOLER ACROSS THE BIG COUNTRY...WHERE HIGHS FRIDAY ARE EXPECTED TO BE IN THE MID/UPPER 90S. THE UPPER HIGH WILL BE CENTERED OVER NEW MEXICO DURING THE WEEKEND. GIVEN ITS PROXIMITY...HOT AND DRY CONDITIONS CAN BE EXPECTED FOR WEST CENTRAL TEXAS. THE WARMEST READINGS ARE EXPECTED SUNDAY...WHEN HIGHS SHOULD RANGE FROM 100-105 DEGREES AREAWIDE. LITTLE CHANGE IS INDICATED WITH THIS PATTERN THROUGH AT LEAST EARLY NEXT WEEK. THE 12Z GFS AND ECMWF SHOW A WEAKENING WITH THIS HIGH BY NEXT TUESDAY OR WEDNESDAY...WITH THE GFS BRINGING A DISTURBANCE NORTH-NORTHEAST FROM THE LOWER RIO GRANDE VALLEY INTO CENTRAL AND EASTERN TEXAS. GIVEN THAT THIS IS LATE DAY 6 AND DAY 7...LEANING AT THIS TIME TOWARD PERSISTENCE WITH THE FORECAST. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 74 101 72 97 70 / 20 10 10 5 5 SAN ANGELO 74 101 73 101 70 / 30 20 10 10 5 JUNCTION 73 97 72 101 70 / 30 20 10 10 5 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 24/19
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
212 PM CDT WED AUG 8 2012 .UPDATE... MADE A QUICK UPDATE TO THE FORECAST FOR THIS AFTERNOON AND EVENING TO INCREASE POPS TO 30 PERCENT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. && .DISCUSSION... SEVERAL WEAK OUTFLOW BOUNDARIES LEFT OVER FROM LAST NIGHT WILL LINGER ACROSS THE AREA AND WILL BE A FOCUS FOR CONVECTIVE DEVELOPMENT THIS AFTERNOON. LIFT WILL ALSO INCREASE ACROSS THE AREA THIS AFTERNOON AS A WEAK SHORT WAVE DROPS SOUTH FROM NORTHWEST TEXAS. LATEST HRRR SHOWS CONVECTION DEVELOPING ACROSS THE HEARTLAND AND CONCHO VALLEY BY 20Z AND ALREADY STARTING TO SEE SOME NEW CELLS DEVELOP OVER BROWN AND COLEMAN COUNTIES. LATEST NAM/RUC ALSO INDICATING CONVECTIVE DEVELOPMENT IN A SIMILAR FASHION. CONFIDENCE HAS INCREASED TO RAISE POPS TO 30 PERCENT ACROSS THE SOUTHERN TWO THIRDS OF THE CWA THROUGH THE EVENING HOURS....WITH CONVECTION DIMINISHING LATER THIS EVENING. UPDATED PRODUCTS WERE SENT. && .PREV DISCUSSION... /ISSUED 1255 PM CDT WED AUG 8 2012/ DISCUSSION... SEE 18Z AVIATION DISCUSSION BELOW. AVIATION... MAIN CHALLENGE THIS FORECAST CYCLE WILL BE CONVECTIVE CHANCES ACROSS THE SOUTHERN TAF SITES THIS AFTERNOON. EXPECT PREDOMINANTLY VFR FOR THE TERMINALS THE NEXT 24 HOURS BUT SCATTERED CONVECTION IS EXPECTED TO DEVELOP MAINLY SOUTH OF THE KABI TERMINAL AFTER 20Z. INCLUDED VCTS FOR ALL TERMINALS EXCEPT KABI THIS AFTERNOON UNTIL 01Z. VISIBILITY AND CIGS WILL BE LOWER WITH ANY CONVECTION THAT OCCURS AND WILL MAKE NECESSARY AMENDMENTS IF NEEDED. LIGHT WINDS WILL CONTINUE THE NEXT 24 HOURS WITH SPEEDS AT OR BELOW 10 KT. PREV DISCUSSION... /ISSUED 623 AM CDT WED AUG 8 2012/ DISCUSSION... AVIATION DISCUSSION FOLLOWS. AVIATION... ISOLATED SHOWERS AND THUNDERSTORMS MAY THREATEN THE KABI... KSJT...AND KBBD TERMINALS THROUGH TODAY. A NIGHT TIME COMPLEX OF STORMS MAY APPROACH THE KABI TERMINAL TONIGHT AFTER MIDNIGHT AND BRING GUSTY NORTH WINDS OF 30 TO 40KTS. STRONG DOWNBURST WINDS IN EXCESS OF 45KTS MIGHT ACCOMPANY ANY OF THE STORMS THAT DEVELOP THIS AFTERNOON AND EVENING. HAVE LEFT OUT MENTION OF WINDS AND TSTORMS IN TAF BECAUSE OF THEIR ISOLATED NATURE. SATELLITE SHOWS A MESOSCALE CONVECTIVE VORTEX NEAR HASKELL THAT WAS SLIDING SOUTH AND WAS PRODUCING A FEW SHOWERS. SHOWERS OR THUNDERSTORMS COULD FORM NEAR THIS FEATURE AS IT TRACKS SOUTH. PREV DISCUSSION... /ISSUED 338 AM CDT WED AUG 8 2012/ SHORT TERM... IMPACTS...GUSTY NORTH WINDS 20 TO 25 MPH...AND ISOLATED LIGHTNING STRIKES THROUGH 9 AM NORTH OF A LINE FROM MARY NEAL TO CROSS PLAINS. ISOLATED DAMAGING WIND GUSTS AND CLOUD TO GROUND LIGHTNING STRIKES THIS AFTERNOON ANYWHERE IN WEST CENTRAL TEXAS. GUSTY NORTH WINDS OF 35 TO 45 MPH AGAIN TONIGHT MAINLY NORTH OF I20. HOT TEMPERATURES ABOVE 100 ACROSS A LARGE PART OF THE WEST CENTRAL TEXAS. DISCUSSION...AT 08Z...THE LEADING EDGE OF AN OUTFLOW BOUNDARY STRETCHED FROM ROBY TO ANSON TO ALBANY AND WAS MOVING SOUTH NEAR 30 MPH. BASED ON THE WEST TEXAS MESONET DATA...WIND GUSTED TO NEAR 39 MPH AT HASKELL AT 0720Z. MOSTLY SHOWERS AND AN ISOLATED THUNDERSTORM CONTINUED TO DEVELOP BEHIND THE BOUNDARY. THE DIURNAL LOW LEVEL JET OF 25 TO 30 KTS ALONG WITH HIGHER DIURNAL CAPE VALUES NEAR 1000 J/KG WERE SUSTAINING THESE STORMS BEHIND THE BOUNDARY. DECIDED TO GO WITH THE HIGHEST POPS NEAR 25 PERCENT ALONG AND NORTH OF INTERSTATE 20 AND THEN 20 POPS SOUTH OF I20. THIS COMPLEX OF STORMS SHOULD CONTINUE BEFORE DIMINISHING AROUND 900 AM AS THE LOW LEVEL JET WEAKENS. THE AFOREMENTIONED OUTFLOW BOUNDARY MAY ALSO SERVE AS A TRIGGER FOR THUNDERSTORMS TO FORM THIS AFTERNOON. CONTINUED 20 POPS FOR MOST OF THE AREA TODAY. WENT WITH HOTTEST TEMPERATURES ACROSS THE SOUTH AND SLIGHTLY COOLER IN THE RAIN COOLED AIR TO THE NORTH. EXPECT A REPEAT PERFORMANCE LATE TONIGHT AS SHOWERS AND THUNDERSTORMS DEVELOP IN THE NORTHWEST FLOW ACROSS THE TEXAS PANHANDLE AND THEN MOVE SOUTH DURING THE NIGHT. FOR TONIGHT...WENT WITH CHC POPS ACROSS THE BIG COUNTRY AND 20 POPS SOUTH. LONG TERM... MODELS HAVE THE 500MB HIGH CENTERED OVER THE FOUR CORNERS AREA THURSDAY MORNING WITH THE NAM MOVING A SHORT WAVE DISTURBANCE EMBEDDED IN THE NORTHERN FLOW ALOFT SOUTH THROUGH THE FORECAST AREA DURING THE ON THURSDAY. THE NAM THEN MOVES A WEAK COLD FRONT THROUGH THE AREA DURING THE DAY ON FRIDAY. THE GFS BRINGS THE COLD FRONT THROUGH THE CWA EARLIER...DURING THE DAY ON THURSDAY. WILL CONTINUE THE SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE DAY ON THURSDAY AND INTO THURSDAY EVENING. SHOULD SEE FRIDAY AND SATURDAY AFTERNOON HIGHS A DEGREE OR TWO COOLER IN THE WAKE OF THE COLD FRONT. THE UPPER HIGH WILL BUILD EAST FOR THE REMAINDER OF THE EXTENDED WITH AFTERNOON HIGHS WARMING A FEW DEGREES BEGINNING SUNDAY. WITH THE EXPANDING UPPER RIDGE OVER THE FORECAST...THE OUTLOOK THROUGH THE REMAINDER OF THE EXTENDED WILL BE HOT AN DRY. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 99 75 100 72 97 / 20 20 10 10 5 SAN ANGELO 101 75 102 73 101 / 30 30 20 20 10 JUNCTION 102 74 103 72 101 / 20 30 20 20 10 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
100 PM EDT WED AUG 8 2012 .SYNOPSIS... A STATIONARY FRONT ACROSS THE MOUNTAINS WILL GRADUALLY DISSIPATE TODAY AS WEAK HIGH PRESSURE SLIDES EAST INTO THE REGION BY TONIGHT BEFORE WEAKENING ON THURSDAY. A STRONG COLD FRONT WILL SWEEP ACROSS THE REGION FRIDAY INTO FRIDAY EVENING...BRINGING ANOTHER ROUND OF SHOWERS AND STORMS...SOME POTENTIALLY STRONG. COOLER AND DRIER WEATHER IS EXPECTED BEHIND THE FRONT OVER THE WEEKEND INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS INTO THE REGION. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1255 PM ED WEDNESDAY... ISOALTED TO SCATTERED SHOWERS AND STORMS HAVE DEVELOPED OVER THE PAST 30 MINUTES GENERALLY ALONG AND EAST OF A LINE FROM WILKES COUNTY NC TO APPOMATTOX COUNTY VA. ANTICIPATE THIS AREA TO BE THE FOCUS FOR ADDITIONAL SHOWERS AND STORMS AS THE AFTERNOON PROGRESSES. CANNOT RULE OUT VERY ISOLATED COVERAGE WEST OF THIS REGION. HAVE MADE ADJUSTMENTS TO THE HOURLY TEMPERATURE...DEW POINT...WINDS AND SKY COVER BASED UPON THE CURRENT OBSERVATIONS AND EXPECTED TRENDS THIS AFTERNOON. THIS PROMPTED AN INCREASE IN THE FORECAST HIGH TEMPERATURES BY TWO TO THREE DEGREES ACROSS THE VIRGINIA PIEDMONT. AS OF 952 AM EDT WEDNESDAY... SURFACE OBSERVATIONS AND VISIBLE SATELLITE IMAGERY INDICATES A FEW POCKETS OF LINGERING FOG IN SOME OF THE MOUNTAIN VALLEYS. HOWEVER...ANTICIPATE THAT BY 1100 AM EDT...MOST OR ALL OF THIS LINGERING FOG WILL HAVE DISSIPATED. PRECIPITATION HAS BEEN LIMITED TO JUST A FEW ISOLATED SHOWERS ACROSS PARTS OF BUCKINGHAM COUNTY VIRGINIA. ANTICIPATE LIMITED...IF ANY COVERAGE...THROUGH NOON BEFORE COVERAGE INCREASES NEAR THE NC/VA BORDER. NO OTHER SIGNIFICANT CHANGES. THE HOURLY TEMPERATURE...DEW POINT...WIND AND SKY COVER GRIDS HAVE BEEN TWEAKED TO REFLECT THE LATEST OBSERVATIONS AND EXPECTED TRENDS INTO THE EARLY AFTERNOON. AS OF 230 AM EDT WEDNESDAY... WEAK SURFACE BOUNDARY ACROSS THE MOUNTAINS WILL GRADUALLY FADE TODAY AS A MID LEVEL WAVE PASSES TO THE EAST BY AFTERNOON AND DRIER AIR ALOFT PER VAPOR LOOP ADVECTS IN FROM THE NW. HOWEVER THE LOW LEVELS WILL REMAIN RATHER MOIST AND GIVEN ANOTHER SUBTLE S/W PUSHING ACROSS THE WEST LATER ON CANT TOTALLY RULE OUT ADDED ISOLATED CONVECTION...ESPCLY BLUE RIDGE AND POINTS EAST...MAINLY SOUTH OF HIGHWAY 460 WHERE BOUNDARY LAYER MOISTURE/INSTABILITY WILL BE BETTER. LATEST LOCAL GUIDANCE AS WELL AS THE SPC WRF AND GFS HINT AT THIS WITH A FEW TSRA CLUSTERS DEVELOPING SW SECTIONS ALONG THE BLUE RIDGE PER DIFF HEATING UNDER WEAK THETA-E RIDGING...AND THEN OUT EAST JUST AHEAD OF WHAT WAS LEFT OF THE OLD FRONT. AGAIN GIVEN WEAK STEERING AND LOCAL CONVERGENCE/OUTFLOW COULD ALLOW FOR STORMS TO POP UP AND DUMP HEAVY RAINFALL BUT NOT THINKING MUCH MORE COVERAGE THAN CHANCE TO ISOLATED POPS TODAY. OTRW EXPECTING A GRADUAL RETURN TO MORE SUNSHINE AS THE HIGH/MID LEVEL CLOUD DECK ERODES AND SHIFTS NE WITH THE PASSAGE OF THE WAVE TO THE EAST THIS MORNING. THINK CLOUDS WILL LIMIT FOG FROM BECOMING TOO WIDESPREAD EXCEPT PERHAPS THE FAR WEST SO WILL KEEP MENTION PENDING RELEASE COVERAGE. WARM START AND SLIGHT 85H WARMING UNDER A WEAK WEST/NW TRAJECTORY ALOFT SHOULD PUSH TEMPS TO AROUND 90 EAST AND WELL INTO THE 80S WEST SO BUMPED UP CLOSER TO THE MAV VALUES TODAY. ANY CONVECTION SHOULD QUICKLY FADE WITH LOSS OF HEATING THIS EVENING GIVEN LACK OF SUPPORT...WITH MAINLY CLEAR SKIES AFTER MIDNIGHT AS WE SLIDE IN BETWEEN THE DEEP MOISTURE LOBE TO THE SE AND THE NEXT UPSTREAM 5H TROF. THUS WILL CARRY SOME ISOLATED EVENING POPS MAINLY SOUTH/EAST THEN GO DRY WITH PERHAPS SOME PATCHY FOG UNDER WEAK HIGH PRESSURE LATE. THIS SHOULD ALSO ALLOW LOW TEMPS TO DROP CLOSER TO THE COOLER MAV FOR THE MOST PART WITH RANGE FROM AROUND 60 VALLEYS TO UPPER 60S SE AND RIDGES. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 430 AM EDT WEDNESDAY... ACTIVE WEATHER WILL BEGIN THE SHORT TERM PERIODS AS THE UPPER FLOW AMPLIFIES ACROSS THE U.S...FEATURING A DEEPENING NEGATIVELY TILTED UPPER TROUGH FROM THE GREAT LAKES TOWARD THE MID-ATLANTIC THU-FRI. THE POPS AND SEVERE THREAT FOR THU SOMEWHAT QUESTIONABLE...BUT A MORE DEFINITE POSSIBILITY FOR FRI AS THE ENTIRE SYSTEM SHIFTS ACROSS THE CWA. NORMALLY SUCH A PATTERN WOULD SUGGEST A HIGH THREAT OF SEVERE WX ACROSS THE REGION...ESPECIALLY FRI. HOWEVER...EXTENSIVE CLOUD COVER AND MORNING SHRA FRI WILL LIKELY LIMIT HEATING...WITH THE GREATER LIKELIHOOD FOR SEVERE PROBABLY FOCUSED ACROSS THE PIEDMONT AND TOWARD THE COASTAL PLAIN FRI AFTERNOON/EVENING. AT THIS POINT...HAVE ONLY MENTIONED GUSTY WINDS AND LOCALLY HEAVY RAIN. SPC HAS OUTLOOKED THE WESTERN SECTIONS ON DAY2 AND THE ENTIRE CWA ON DAY3...BUT AGAIN FEEL MAIN THREAT ON DAY3 SHOULD BE EAST OF THE BLUE RIDGE. MODEL AND HPC QPF NOT OVERLY IMPRESSIVE AND INDICATIVE OF A SKIP OVER EFFECT OF THE HEAVIEST PRECIPITATION AS AFOREMENTIONED TOWARD EASTERN VA/NC. NONETHELESS...WITH FAIRLY WIDESPREAD HEAVY RAIN ACROSS THE MOUNTAIN AREAS DURING THE PAST COUPLE OF WEEKS...LATER SHIFTS WILL NEED TO EVALUATE THE ISSUANCE OF AN FFA WEST OF THE BLUE RIDGE WHERE 1HR FFG VALUES GENERALLY LESS THAN 2 INCHES. WITH REFERENCE TO POP TIMING...ENOUGH FORCING APPEARS EVIDENT COMBINED WITH PRE-SYSTEM HEATING TO SUPPORT GOOD CHC POPS EAST TO LIKELY POPS WEST BY FRI EVENING. WILL HAVE LIKELY POPS TO ALL AREAS FRI...WHICH MAY WELL BECOME CATEGORICAL WITH LATER FORECASTS. 850MB TEMPS NEAR +20C ACROSS THE PIEDMONT REGION THU WILL STILL SUPPORT WELL ABOVE NORMAL TEMPS IN THE LOW TO MID 90S EAST OF THE BLUE RIDGE...WITH MOSTLY 80S TO THE WEST...EXCEPT 70S IN THE MOUNTAINS ABOVE 3000 FT. EXTENSIVE CLOUD COVER AND SHRA/TSRA FRI SHOULD HOLD TEMPS TO THE 70S IN THE MOUNTAINS TO 80S EAST OF THE BLUE RIDGE. LATEST MODELS HAVE COME INTO BETTER AGREEMENT IN PUSHING THE MAIN UPPER TROUGH EAST OF THE REGION BY EARLY SAT...WHICH SHOULD TAKE THE BULK OF THE PCPN WITH IT. HOWEVER...THE PARENT...RATHER DEEP UPPER LOW FOR MID-AUGUST...WILL SWEEP THROUGH CENTRAL PA SAT AND COULD PROMOTE ENOUGH LIFT IN UPSLOPE AREAS OF WV/N VA TO SUPPORT ISOLD -SHRA DURING DAYTIME HEATING...THUS HAVE INCLUDED SLIGHT CHC POPS ACCORDINGLY. 850MB TEMPS DROP TO THE LOWEST LEVELS SEEN IN OVER TWO MONTHS...WITH +10C ACROSS ALL EXCEPT THE PIEDMONT BY 12Z SAT. THIS SHOULD ALLOW FOR SOME RATHER REFRESHING HIGHS IN THE 70S WEST OF THE BLUE RIDGE AND 80S EAST...WITH DEWPOINTS DROPPING INTO THE 50S WEST OF THE BLUE RIDGE AND 60S ACROSS THE PIEDMONT. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 430 AM EDT WEDNESDAY... HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM AT THIS TIME. IT APPEARS THAT A RATHER UNSETTLED WEATHER PATTERN WILL REMAIN IN PLACE THROUGHOUT THE EXTENDED AS A SERIES OF NW FLOW DISTURBANCES TRACK ACROSS THE REGION. THE ECMWF/GFS ARE AT ODDS WITH RESPECT TO THE AMPLIFICATION OF THE NEXT UPPER TROUGH TOWARD THE MIDDLE OF NEXT WEEK... WITH THE GFS FAVORING A FLATTER...MORE ZONAL FLOW. AT ANY RATE...IT APPEARS THAT AT LEAST CHC POPS FOR SHRA/TSRA WILL CONTINUE THROUGHOUT THE EXTENDED WITH TEMPS RETURNING BACK TO AOA NORMAL LEVELS. LOW-LEVEL MOISTURE WILL ALSO BE INCREASING...RESULTING IN INCREASINGLY MORE HUMID CONDITIONS AS WELL. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 645 AM EDT WEDNESDAY... EXTENSIVE MID AND HIGH CLOUD CANOPY ASSOCIATED WITH WAVE/UPPER JET CONTINUES TO SLOWLY PUSH EAST AND SHOULD EXIT THE AREA BY MID MORNING IF NOT SOONER. MAY SEE A FEW ADDED SHRA DEVELOP OVER THE SW THIS MORNING BUT MOSTLY SOUTH OF THE TAF SITES. OTRW FOG THE MAIN CONCERN AGAIN EARLY THIS MORNING WITH AREAS OF IFR/LIFR IN THE VALLEYS/ALONG THE WESTERN RIDGES...PRIMARILY KLWB/KBLF AND KBCB IN THE WEST AND KLYH IN THE EAST. MAY STILL SEE A BRIEF PERIOD OF MVFR IN FOG AT KDAN OTRW VFR AROUND KROA. SHOULD SEE MOST OF THE FOG/STRATUS ERODE BY 14Z...10AM WITH ONLY KLWB LIKELY HANGING ONTO POCKETS OF LOWER VSBYS A WHILE LONGER. ONCE THE FOG FADES AND THE MID DECK EXITS SHOULD SEE MAINLY VFR FOR MOST OF THE DAY WITH SCTD-BKN 4-6K FT CU FIELDS. ISOLATED CONVECTION AGAIN POSSIBLE ESPCLY IN SPOTS ALONG THE BLUE RIDGE AND OUT EAST SO INCLUDED A VCTS MENTION FROM KROA EAST BASED ON THE LATEST HRRR MODEL WHICH SHOWS A FEW CLUSTERS DEVELOPING FROM NW NC INTO THE VA PIEDMONT BY MID AFTERNOON. ELSW WILL LEAVE OUT FOR NOW GIVEN ISOLATED NATURE. AGAIN EXPECT ANY STORMS TO DIMINISH WITH LOSS OF HEATING FOLLOWED BY MAINLY CLEAR SKIES WITH ANOTHER ROUND OF MVFR/IFR FOG ESPCLY VALLEYS GIVEN LESS CLOUD COVER OVERNIGHT. PROXIMITY OF THE OLD FRONT AND TROPICAL AIRMASS JUST TO THE SOUTH... WHICH WILL BEGIN A NORTHWARD RETURN BY LATE WEEK...WILL MAINTAIN A DAILY THREAT FOR PATCHY FLIGHT RESTRICTIONS IN VICINITY OF MAINLY DIURNALLY DRIVEN SHOWERS/STORMS FOR MUCH OF THE REST OF THE WEEK...WITH A CONTINUED THREAT FOR RESTRICTIONS INTO THE OVERNIGHT PERIODS WHERE FOG DEVELOPS. MORE WIDESPREAD SHRA/TSRA LIKELY BY WEEKS END AHEAD OF A STRONGER COLD FRONT THAT LOOKS TO DIVE THRU THE REGION FRIDAY INTO FRIDAY NIGHT. IMPROVING CONDITIONS TO VFR LIKELY BEHIND THE FRONT ESPCLY ACROSS THE EAST FOR THE WEEKEND. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH NEAR TERM...DS/JH SHORT TERM...RAB LONG TERM...PH/RAB AVIATION...DS/JH/KM