Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 07/27/07

AREA FORECAST DISCUSSION
NWS DENVER CO
255 PM MDT WED JUL 25 2007 .SHORT TERM...UPPER LEVEL RIDGE STILL REMAINS IN PLACE ACROSS CWA WITH UPPER TROUGH OVER PACIFIC NORTHWEST. CONSIDERABLE SUBTROPICAL MOISTURE HAS SHIFTED ACROSS THE MOUNTAINS AS NOTED BY WATER VAPOR LOOPS. RADAR SHOWING FAIRLY ACTIVE CONVECTION OVER THE MOUNTAINS AND HIGHER FOOTHILLS...ONLY SCATTERED IN COVERAGE. FAIRLY WEAK FLOW ALOFT...SO STORMS ARE HUGGING HIGHER TERRAIN. HEAVY RAIN WITH LOCALIZED FLOODING COULD BE A CONCERN DUE TO THE SLOW MOVEMENT. WITH SOME SLIGHT COOLING ALOFT...A FEW STORMS COULD PRODUCE SOME SMALL HAIL. NO STORMS YET OVER PLAINS AS ACARS SOUNDING SHOWING WEAK CAP AROUND 600 MB. BUT OUTFLOW FROM FOOTHILL STORMS SHOULD BREAK CAP AND ALLOW FOR SOME STORM DEVELOPMENT ALONG URBAN CORRIDOR THIS EVENING. STILL SOME CHANCE FOR A STORMS ACROSS PLAINS AS WELL...RELYING PRIMARILY ON ANY OUTFLOW BOUNDARIES. UPPER TROUGH SLOWLY MAKES ITS WAY INTO NORTHERN GREAT BASIN OVERNIGHT AS SURFACE FRONT CURRENTLY LOCATED IN NORTHERN WYOMING AND WESTERN SOUTH DAKOTA PUSHES INTO NORTHEAST PLAINS. GIVEN COMBINATION OF UPPER DYNAMICS WITH TROUGH AND CONVERGENCE OF SURFACE FRONT...WILL KEEP THE SLIGHT CHANCE OF STORMS GOING OVERNIGHT. ON THURSDAY...QG VERTICAL VELOCITY PROGS SHOW UPPER TROUGH SLIDING ACROSS WYOMING AS CENTER OF RIDGE AXIS SHIFTS SOUTH. QG VERTICAL VELOCITY PROGS SHOW INCREASING ASCENT BY AFTERNOON ACROSS ACROSS CWA. AT THE SURFACE...MODELS INDICATE ANOTHER FRONT MOVING ACROSS PLAINS BY 18Z. GOOD DYNAMICS AND UPSLOPE SHOULD PROVIDE DECENT CONVECTION FOR HIGHER TERRAIN ALONG FOOTHILLS AND PALMER DIVIDE...SUFFICIENT FOR LIKELY POPS. A BIT UNCERTAIN ON STORM POTENTIAL EAST OF FOOTHILLS AS TIMING OF FRONT COULD INITIALLY STABILIZE THE ATMOSPHERE AND HINDER DEVELOPMENT INITIALLY. MODEL QPF ACTUALLY SHOWING THIS PATTERN...WITH HIGHEST QPF ALONG FOOTHILLS AND PALMER DIVIDE. WILL KEEP THE SCATTERED POPS FOR PLAINS ZONES AT THIS TIME. AS FOR MOUNTAINS...BEST CHANCE FOR CONVECTION EAST OF CONTINENTAL DIVIDE GIVEN BETTER UPSLOPE. MODELS SHOW PRECIPITABLE WATER VALUES AROUND 1.3 INCHES DURING AFTERNOON. WINDS ALOFT REMAIN FAIRLY LIGHT...SO HEAVY RAIN AGAIN A THREAT WITH THE STORMS...ALONG WITH LOCALIZED FLOODING. MAIN AREA OF FLOODING CONCERN LOOKS TO BE SOUTHERN FOOTHILLS AT THIS POINT. WILL HOLD OFF ON A FLASH FLOOD WATCH AT THIS TIME...DUE TO UNCERTAINTY OF FRONTAL PASSAGE. FORECAST SOUNDINGS SHOW CAPES OF AROUND 1500 J/KG...SO SOME OF THE STRONGER STORMS COULD PRODUCE HAIL. BUT WITH FREEZING LEVELS AROUND 16000 FEET AGL...THREAT FOR LARGE HAIL LOOKING LOW. AS FOR TEMPERATURES... LATEST GUIDANCE NOW SHOWING HIGHS ACROSS THE PLAINS AROUND 80 DEGREES. WILL NEED TO SHAVE A FEW MORE DEGREES OFF THE CURRENT TEMPERATURE GRIDS. .LONG TERM...UNSEASONABLY COOL AND MOIST UPSLOPE FLOW WILL CONTINUE EAST OF THE COLORADO FRONT RANGE THURSDAY NIGHT AS A 1018MB SFC HIGH TO OUR NORTH CONTINUES TO PRODUCE 5-15KT ELY BNDRY LYR FLOW THRU FRIDAY MORNING ACCORDING TO THE WRF AND GFS. LOOKING FOR LIGHT NWLY FLOW ALOFT TO CARRY EVENING STORMS OFF THE FRONT RANGE AND OVER THE ADJACENT PLAINS. VERY SLOW FORWARD MOTIONS MAY RESULT IN LOCALLY HVY RAINFALL ESPCLY OVER AND NEAR THE FOOTHILLS AND ON THE PALMER DIVIDE PRIOR TO 06Z/FRI WITH PRECIPITABLE WATER VALUES WELL OVER AN INCH. RAIN AMOUNTS OF 1-2 INCHES A POSSIBILITY. AFTER MIDNIGHT...T-STORMS GIVE WAY TO SHOWERY PRECIPITATION WITH MARGINALLY UNSTABLE UPSLOPE FLOW CONTINUING. SPATIAL CROSS SECTIONS SHOW NEARLY SATURATED CONDITIONS UP THRU 600 MBS UP AGAINST THE FRONT RANGE FRIDAY MORNING. THUS LOW CLOUD CIGS AND PATCHY FOG A GOOD BET IN THIS AREA TOGETHER WITH A FEW LIGHT RAIN SHOWERS OR DRIZZLE. BY FRIDAY AFTERNOON...LIGHT ELY LOW-LEVEL FLOW SHIFTS TO A SELY COMPONENT WHICH MODELS SHOW SPINNING UP A DENVER CYCLONE AND CONVERGENCE BNDRY JUST EAST OF THE DENVER METRO AREA. HOWEVER...POST FRONTAL AIRMASS NO LONGER AS UNSTABLE AS THAT OBSERVED THE DAY BEFORE. BUT HIGHER TERRAIN ABOVE THE FRONTAL INVERSION SHOULD SEE ANOTHER ROUND OF AFTERNOON T-STORMS. SOME OF THOSE SHOULD DRIFT E-SEWRD OFF THE HILLS AND OUT ACROSS THE ADJACENT PLAINS BY AFTERNOON. MAY ALSO SEE STORMS FIRING ALONG THE ABOVE MENTIONED DENVER CONVERGENCE BNDRY SOMETIME AFTER 18Z...BUT 0-3KM CAPES AND LAPSE RATES ONLY MARGINALLY FAVORABLE FOR WELL DVLPD STORM CELL FORMATION DUE TO UNSEASONABLY COOL SFC TEMPERATURES. AS FOR TEMPERATURES...MOS GUIDANCE ESPCLY THE ETA MOS...LOOKS TOO COOL. PREFER THE WARMER TEMPERATURES OFFERED BY THE GFS MOS GUIDANCE. BELIEVE ETA/WRF TOO WET AND THEREFORE TOO COOL. ON SATURDAY...YET ANOTHER RIPPLE MOVING ALONG NWLY FLOW ALOFT EXPECTED TO GENERATE ANOTHER ROUND OF AFTERNOON/EVENING CLOUDS AND T-STORMS. SFC-500MB LAYER STILL LOOKS QUITE MOIST WITH SELY ANTICYCLONIC FLOW ADVECTING 50S/LOWER 60S DEWPTS UP INTO NERN COLORADO DURING THE DAY. FOR THAT REASON HAVE RAISED POPS AND SLOWED WARMING ON SATURDAY. SUNDAY AND BEYOND...AIRMASS BEGINS TO DRY AND WARM AS THE HOT UPPER RIDGE OVER THE FOUR CORNERS REGIONS STARTS TO SHIFT BACK OVER THE STATE. HOWEVER MONSOONAL MOISTURE TRAPPED BENEATH THE RIDGE WILL CONTINUE TO SPARK AT LEAST ISOLATED AFTERNOON/EVENING T-STORMS MAINLY IN THE HIGH COUNTRY THRU MID-WEEK. .AVIATION...VFR THROUGH TONIGHT. A FEW STORMS COULD AFFECT DIA THROUGH 03Z...WITH GUSTY OUTFLOW WINDS THE MAIN THREAT. BRIEF HEAVY RAIN ALSO POSSIBLE. A COLD FRONT WILL MOVE INTO THE AREA BEFORE SUNRISE WHICH MAY LEAD TO THE DEVELOPMENT OF SOME STRATUS AND MVFR CONDITIONS AROUND 12Z THURSDAY. A BETTER CHANCE FOR STORMS TO AFFECT THE AIRPORT AFTER 18Z...WITH HEAVY RAIN AND GUSTY WINDS. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. && $$ D_L/BAKER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
300 PM CDT WED JUL 25 2007 .DISCUSSION... 300 PM CDT THE PERSISTENT UPPER LOW CONTINUES TO SLOWLY TRACK WWD THROUGH NRN OHIO TODAY. CONTINUED NELY FLOW ALOFT ASSD WITH THE SYSTEM HAS KEPT THE ERN PORTIONS OF THE CWA UNDER PARTLY TO MOSTLY CLOUDY SKIES WHILE THE WRN SECTIONS HAVE BEEN MOSTLY CLEAR. THE PRESENCE OF THE UPPER LOW HAS TAMED TEMPERATURES SOMEWHAT...KEEPING TEMPS A BIT BELOW SEASONAL NORMALS AND COMPENSATING SUBSIDENCE AHEAD OF THE LOW HAS KEPT THE REGION GENERALLY DRY. THE EXCEPTION HAS BEEN OVER NRN INDIANA AND NERN IL AS WELL AS PORTIONS OF SRN LAKE MICHIGAN. THE ONLY SIGNIFICANT SURFACE REFLECTION OF THE CLOSED UPPER LOW HAS BEEN SOME WEAK SFC CONVERGENCE...WHICH HAS ALLOWED ISOLD-SCT SHRA TO DEVELOP...PARTICULARLY DURG THE DAYLIGHT HOURS. THE 12Z MODEL GUIDANCE CONTINUES TO BE IN DECENT AGREEMENT ON HANDLING THE UPPER LOW AND ALSO EXHIBITS GOOD RUN TO RUN CONTINUITY ON HANDLING THE SYSTEM. THE CENTER OF THE LOW WILL BEGIN TO TURN NELY OVERNIGH TONIGHT AND THEN GET PICKED UP IN THE MEAN WESTERLIES AND EVOLVE INTO AN OPEN WAVE OVER THE ERN GREAT LAKES FRIDAY. THE GFS MAINTAINS A CLOSED LOW A LITTLE LONGER THAN THE NAM...BUT THIS WILL HAVE LITTLE OR NO IMPACT ON THE FORECAST FOR THE LOCAL AREA. THE TREND FOR THE REMAINDER OF THE SHORT TERM WILL BE INCREASING TEMPERATURES WITH INCREASING POPS. THE NEXT SYSTEM TO IMPACT THE LOCAL AREA IS SHAPING UP OVER THE NRN ROCKIES IN THE FORM OF A STRONG SHORT WAVE TROUGH. AGAIN...THE VARIOUS MODEL GUIDANCE IS SHOWING RELATIVELY GOOD CONSISTENCY IN HANDLING THIS FEATURE. THE DIFFERENCES IN THE GUIDANCE ARE MINOR...SO HAVE GENERALLY FOLLOWED THE HIGHER RESOLUTION NAM12 FOR THE SHORT TERM AND TRANSITIONED OVER TO THE GFS40/NCEP MANUAL GUIDANCE FOR THE LONGER TERM FORECAST. THE ONLY MINOR ADJUSTMENTS TO THE GUIDANCE HAVE BEEN TO LOWER DEWPOINTS OVER THE CWA A BIT. HAVE DIFFICULTY BELIEVING THAT DEWPOINTS WILL REACH INTO THE 70S GIVEN THAT THERE IS NO SIGNIFICANT SLY FLOW OFF OF THE CLIMAX DEVELOPING. EVAPOTRANSPORATION FROM GROWING CROPS MAY CONTRIBUTE TO INCREASING LOW LEVEL MOISTURE...SO HAVE MAINTAINED DEWPOINTS IN THE MID TO UPPER 60S AHEAD OF AN APPROACHING COLD FRONT ASSOCIATED WITH THE UPPER SYSTEM. TIMING OF FRONTAL PASSAGE IS BECOMING A BIT CLEARER...REACHING NWRN PORTIONS OF THE CWA BY EARLY AFTERNOON FRIDAY...TRACKING SEWD AND CLEARING THE NWRN INDIANA COUNTIES BY EARLY SATURDAY MORNING. THIS SYSTEM WILL BRING OUR NEXT CHANCE FOR SIGNIFICANT RAINFALL AND THE CURRENT FORECAST HAS AROUND A HALF INCH OF AREAL AVERAGE QPF FOR THE PERIOD FROM FRIDAY MORNING THROUGH SATURDAY MORNING...WITH LOCALLY HIGHER AMOUNTS VERY LIKELY SINCE FORECAST PRECIPITABLE WATER VALUES ALONG AND AHEAD OF THE FRONTAL BOUNDARY ARE AROUND 2 INCHES. FOLLOWING THE FRONTAL PASSAGE...CONDITIONS WILL QUICKLY CLEAR OUT WITH NEAR NORMAL OR SLIGHTLY BELOW NORMAL TEMPERATURES EXPECTED FOR THE WEEKEND AND EARLY NEXT WEEK. A LARGE AREA OF SFC HIGH PRESSURE WILL BUILD IN BEHIND THE COLD FRONT...SETTING UP A PERIOD OF LARGE SCALE SUBSIDENCE...WITH MOSTLY CLEAR SKIES AND RELATIVELY LOW HUMIDITY. KREIN && .AVIATION... 100 PM CDT FOR THE AFTERNOON TAFS THE SHOWERS WILL BE NEAR ORD...MDW AND GYY. A SURFACE TEMPERATURE MAXIMUM LIES FROM STEVENS POINT WISCONSIN TO MILWAUKEE WISCONSIN. THE 700 MB PROFILER DATA SHOWS A WEST TO EAST RIDGE JUST NORTH OF THE ILLINOIS BORDER AT 15 UTC STREAMLINE ANALYSIS. A 40 KNOT JET IS MOVING SOUTHWEST ACROSS LAKE MICHIGAN AND IT WILL MOVE INTO NORTHEAST ILLINOIS BY THIS EVENING. THE WARM AIR AT THE SURFACE PROVIDES A NEAR ADIABATIC SOUNDING SEEN ON THE ACARS DATA FOR ORD AT 1645 UTC. WILL KEEP SHOWERS IN THE VICINITY THROUGH 22 UTC NEAR ORD AND MDW AND GYY. WE EXPECT A LAKE BREEZE THIS AFTERNOON AS WELL. THE WIND WILL BE VERY LIGHT FROM THE SOUTH. WE EXPECT THE SOUTHWEST WIND THROUGH THE NIGHT AND WILL KEEP THE 10 TO 15 THOUSAND FOOT CLOUDS IN THE FORECAST OVERNIGHT. && .MARINE... 200 PM CDT THE CIRCULATION AND SMALL LOW OVER EASTERN WISCONSIN WILL DRIFT OVER THE LAKE TONIGHT. BY THURSDAY MORNING IT WILL BE OVER CENTRAL LAKE MICHIGAN. WE USED THE WRF ARW MODEL AND GFS MODEL FOR THE FORECAST POSITION OF THE LOW AND THE WRF NMM MODEL FOR THE WIND SPEED TONIGHT. A WEAK JET STEAK IS MOVING OVER LAKE MICHIGAN BEHIND THE UPPER AIR LOW OVER NORTHERN OHIO. THIS MAY GIVE SOME UPPER AIR SUPPORT TO THE LOW OVER THE LAKE. BUT AS NIGHT FALLS THE LAPSE RATE BELOW 850 MB WILL DECREASE SIGNIFICANTLY SO WE WILL DROP THE SPEED OF THE WIND A LITTLE TONIGHT FROM THE MODEL FORECASTS. WILL KEEP THE WIND FORECAST FOR THE LAKE 15 TO 20 KNOTS TONIGHT AND THURSDAY. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
200 PM CDT WED JUL 25 2007 .DISCUSSION... 300 AM CDT SLOWLY BUT SURELY...THE CUTOFF LOW OUT TO OUR EAST THAT HAS JAMMED UP OUR WEATHER PATTERN WILL BEGIN PROPAGATING OUT OF THE REGION ON THURSDAY. THE MODEL CONSENSUS THE PAST FEW DAYS HAS BEEN TO BRING THE CUTOFF LOW INTO SOUTHERN MICHIGAN LATE THURSDAY AND TRANSITIONING IT TO AN OPEN WAVE IN SOUTHEASTERN CANADA BY SATURDAY. THE MAIN PUSH THAT IS GOING TO BUDGE THIS ALONG IS THE PACIFIC SYSTEM THAT MADE LANDFALL LATE MONDAY AND IS CURRENTLY CLIMBING ALONG THE PERIPHERY OF THE STRONG MID-LEVEL RIDGE EXTENDING INTO THE HUDSON BAY. THIS WILL HELP TO DEEPEN THE CANADIAN TROF AND THUS PICK UP THE MEANDERING CUTOFF LOW. THIS CUTOFF LOW HAS ACTUALLY BEEN A SAVIOR OF SORTS AS EARLIER FORECAST RUNS...THAT DID NOT HAVE THIS LOW RETROGRADING INTO OUR REGION...HAD THE AMPLIFIED WESTERN RIDGE AXIS DIRECTLY OVER US FOR AN EXTENDED PERIOD OF TIME. THIS PROBABLY WOULD HAVE MEANT HIGH TEMPS IN THE 90S AND DEW POINTS IN THE 70S. THIS LOW HAS KEPT TEMPERATURES AND DEW POINTS FAIRLY SEASONAL...IF NOT A LITTLE BELOW NORMAL. BACK TO THE FORECAST...THE FOCUS OVER THE NEXT FEW DAYS WILL BE ON PRECIP CHANCES. BACKED OFF ON A FEW PERIODS THAT PREVIOUSLY HAD MENTION OF THUNDER AS IT APPEARS THAT THE BEST CHANCE FOR THAT WILL BE WHEN THE ACTUAL CORE OF THE CUTOFF LOW GETS INTO SOUTHERN MICHIGAN AND WHEN THE COLD FRONT DROPS THROUGH ON FRIDAY. WILL HAVE TO MONITOR ANY SHORTWAVES ROTATING ALONG THE MID-LEVEL LOW AS THAT WILL PROVIDE BETTER FOCUS FOR SHOWER DEVELOPMENT. AT THE MOMENT...IT APPEARS AS THE ONLY SHORTWAVE IS THE ONE EXTENDING SOUTHWARD OUT OF THE LOW ALONG THE APPALACHIANS. UPPED POPS FOR FRIDAY AS IT APPEARS THAT THE GULF WILL BE OPEN FOR BUSINESS AND SHOULD SUPPLY ENOUGH MOISTURE TO HELP DEVELOP A LINE OF SHOWERS AND STORMS OUT AHEAD OF THE FRONT. ANY SEVERE POTENTIAL SEEMS MINIMAL AT THIS POINT AS CAPE VALUES ONLY GET TO AROUND 1000 J/KG AND HARDLY ANY WIND SHEAR TO SPEAK OF. MID-LEVEL LAPSE RATES ARE NOT ALL THAT IMPRESSIVE EITHER AS THE MAIN MID-LEVEL HEIGHT FALLS WILL BE WELL NORTH IN CANADA. AS THE FRONT PASSES...SKIES WILL EVENTUALLY CLEAR OUT FOR THE REST OF THE WEEKEND. AS FOR TEMPERATURES...NOT MANY CHANGES MADE TO THE GOING FORECAST. THURSDAY NIGHT INTO FRIDAY WILL LIKELY BE THE WARMEST PORTION OF THE FORECAST PERIOD AS WARM AIR FROM THE WESTERN RIDGE FINALLY ADVECTS INTO THE REGION OUT AHEAD OF THE COLD FRONT. NOT MUCH OF A COLD/DRY PUNCH BEHIND THIS FRONT AS TEMPS WILL REMAIN AROUND NORMAL FOR THIS TIME OF YEAR. HALBACH && .AVIATION... 100 PM CDT FOR THE AFTERNOON TAFS THE SHOWERS WILL BE NEAR ORD...MDW AND GYY. A SURFACE TEMPERATURE MAXIMUM LIES FROM STEVENS POINT WISCONSIN TO MILWAUKEE WISCONSIN. THE 700 MB PROFILER DATA SHOWS A WEST TO EAST RIDGE JUST NORTH OF THE ILLINOIS BORDER AT 15 UTC STREAMLINE ANALYSIS. A 40 KNOT JET IS MOVING SOUTHWEST ACROSS LAKE MICHIGAN AND IT WILL MOVE INTO NORTHEAST ILLINOIS BY THIS EVENING. THE WARM AIR AT THE SURFACE PROVIDES A NEAR ADIABATIC SOUNDING SEEN ON THE ACARS DATA FOR ORD AT 1645 UTC. WILL KEEP SHOWERS IN THE VICINITY THROUGH 22 UTC NEAR ORD AND MDW AND GYY. WE EXPECT A LAKE BREEZE THIS AFTERNOON AS WELL. THE WIND WILL BE VERY LIGHT FROM THE SOUTH. WE EXPECT THE SOUTHWEST WIND THROUGH THE NIGHT AND WILL KEEP THE 10 TO 15 THOUSAND FOOT CLOUDS IN THE FORECAST OVERNIGHT. && .MARINE... 200 PM CDT THE CIRCULATION AND SMALL LOW OVER EASTERN WISCONSIN WILL DRIFT OVER THE LAKE TONIGHT. BY THURSDAY MORNING IT WILL BE OVER CENTRAL LAKE MICHIGAN. WE USED THE WRF ARW MODEL AND GFS MODEL FOR THE FORECAST POSITION OF THE LOW AND THE WRF NMM MODEL FOR THE WIND SPEED TONIGHT. A WEAK JET STEAK IS MOVING OVER LAKE MICHIGAN BEHIND THE UPPER AIR LOW OVER NORTHERN OHIO. THIS MAY GIVE SOME UPPER AIR SUPPORT TO THE LOW OVER THE LAKE. BUT AS NIGHT FALLS THE LAPSE RATE BELOW 850 MB WILL DECREASE SIGNIFICANTLY SO WE WILL DROP THE SPEED OF THE WIND A LITTLE TONIGHT FROM THE MODEL FORECASTS. WILL KEEP THE WIND FORECAST FOR THE LAKE 15 TO 20 KNOTS TONIGHT AND THURSDAY. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
100 PM CDT WED JUL 25 2007 .DISCUSSION... 300 AM CDT SLOWLY BUT SURELY...THE CUTOFF LOW OUT TO OUR EAST THAT HAS JAMMED UP OUR WEATHER PATTERN WILL BEGIN PROPAGATING OUT OF THE REGION ON THURSDAY. THE MODEL CONSENSUS THE PAST FEW DAYS HAS BEEN TO BRING THE CUTOFF LOW INTO SOUTHERN MICHIGAN LATE THURSDAY AND TRANSITIONING IT TO AN OPEN WAVE IN SOUTHEASTERN CANADA BY SATURDAY. THE MAIN PUSH THAT IS GOING TO BUDGE THIS ALONG IS THE PACIFIC SYSTEM THAT MADE LANDFALL LATE MONDAY AND IS CURRENTLY CLIMBING ALONG THE PERIPHERY OF THE STRONG MID-LEVEL RIDGE EXTENDING INTO THE HUDSON BAY. THIS WILL HELP TO DEEPEN THE CANADIAN TROF AND THUS PICK UP THE MEANDERING CUTOFF LOW. THIS CUTOFF LOW HAS ACTUALLY BEEN A SAVIOR OF SORTS AS EARLIER FORECAST RUNS...THAT DID NOT HAVE THIS LOW RETROGRADING INTO OUR REGION...HAD THE AMPLIFIED WESTERN RIDGE AXIS DIRECTLY OVER US FOR AN EXTENDED PERIOD OF TIME. THIS PROBABLY WOULD HAVE MEANT HIGH TEMPS IN THE 90S AND DEW POINTS IN THE 70S. THIS LOW HAS KEPT TEMPERATURES AND DEW POINTS FAIRLY SEASONAL...IF NOT A LITTLE BELOW NORMAL. BACK TO THE FORECAST...THE FOCUS OVER THE NEXT FEW DAYS WILL BE ON PRECIP CHANCES. BACKED OFF ON A FEW PERIODS THAT PREVIOUSLY HAD MENTION OF THUNDER AS IT APPEARS THAT THE BEST CHANCE FOR THAT WILL BE WHEN THE ACTUAL CORE OF THE CUTOFF LOW GETS INTO SOUTHERN MICHIGAN AND WHEN THE COLD FRONT DROPS THROUGH ON FRIDAY. WILL HAVE TO MONITOR ANY SHORTWAVES ROTATING ALONG THE MID-LEVEL LOW AS THAT WILL PROVIDE BETTER FOCUS FOR SHOWER DEVELOPMENT. AT THE MOMENT...IT APPEARS AS THE ONLY SHORTWAVE IS THE ONE EXTENDING SOUTHWARD OUT OF THE LOW ALONG THE APPALACHIANS. UPPED POPS FOR FRIDAY AS IT APPEARS THAT THE GULF WILL BE OPEN FOR BUSINESS AND SHOULD SUPPLY ENOUGH MOISTURE TO HELP DEVELOP A LINE OF SHOWERS AND STORMS OUT AHEAD OF THE FRONT. ANY SEVERE POTENTIAL SEEMS MINIMAL AT THIS POINT AS CAPE VALUES ONLY GET TO AROUND 1000 J/KG AND HARDLY ANY WIND SHEAR TO SPEAK OF. MID-LEVEL LAPSE RATES ARE NOT ALL THAT IMPRESSIVE EITHER AS THE MAIN MID-LEVEL HEIGHT FALLS WILL BE WELL NORTH IN CANADA. AS THE FRONT PASSES...SKIES WILL EVENTUALLY CLEAR OUT FOR THE REST OF THE WEEKEND. AS FOR TEMPERATURES...NOT MANY CHANGES MADE TO THE GOING FORECAST. THURSDAY NIGHT INTO FRIDAY WILL LIKELY BE THE WARMEST PORTION OF THE FORECAST PERIOD AS WARM AIR FROM THE WESTERN RIDGE FINALLY ADVECTS INTO THE REGION OUT AHEAD OF THE COLD FRONT. NOT MUCH OF A COLD/DRY PUNCH BEHIND THIS FRONT AS TEMPS WILL REMAIN AROUND NORMAL FOR THIS TIME OF YEAR. HALBACH && .AVIATION... 100 PM CDT FOR THE AFTERNOON TAFS THE SHOWERS WILL BE NEAR ORD...MDW AND GYY. A SURFACE TEMPERATURE MAXIMUM LIES FROM STEVENS POINT WISCONSIN TO MILWAUKEE WISCONSIN. THE 700 MB PROFILER DATA SHOWS A WEST TO EAST RIDGE JUST NORTH OF THE ILLINOIS BORDER AT 15 UTC STREAMLINE ANALYSIS. A 40 KNOT JET IS MOVING SOUTHWEST ACROSS LAKE MICHIGAN AND IT WILL MOVE INTO NORTHEAST ILLINOIS BY THIS EVENING. THE WARM AIR AT THE SURFACE PROVIDES A NEAR ADIABATIC SOUNDING SEEN ON THE ACARS DATA FOR ORD AT 1645 UTC. WILL KEEP SNOWERS IN THE VICINITY THROUGH 22 UTC NEAR ORD AND MDW AND GYY. WE EXPECT A LAKE BREEZE THIS AFTERNOON AS WELL. THE WIND WILL BE VERY LIGHT FROM THE SOUTH. WE EXPECT THE SOUTHWEST WIND THROUGH THE NIGHT AND WILL KEEP THE 10 TO 15 THOUSAND FOOT CLOUDS IN THE FORECAST OVERNIGHT. && .MARINE... 145 AM CDT SHOULD GENERALLY SEE SOUTHERLY WINDS OVER THE OPEN WATERS OF THE LAKE THROUGH FRIDAY MORNING. WHILE GENERAL SYNOPTIC FLOW WILL FAVOR SOUTHERLY WINDS...GRADIENT EXPECTED TO REMAIN WEAK ENOUGH TO ALLOW DEVELOPMENT OF AFTERNOON LAKE BREEZES AND WEAK NIGHTTIME LAND BREEZES OVER THE NEARSHORE WATERS. COLD FRONT STILL SLATED TO DROP DOWN THE LAKE DURING THE DAY FRIDAY AS ANOTHER CANADIAN HIGH BUILDS SOUTHWARD INTO THE GREAT LAKES REGION FRIDAY NIGHT INTO SATURDAY. THIS WEEKENDS HIGH IS PROGGED TO BE WEAKER THAN THE LAST HIGH THAT KICKED UP GALES OVER THE LAKE. DESPITE THIS HIGH BEING A BIT WEAKER...THE LAKE CONTINUES TO WARM AND WITH A MODEST PUSH OF COLD AIR ADVECTION REALLY NOT EXPECTING TO SEE OVERLY STABLE CONDITIONS OVER THE WATER SO WILL PROBABLY SEE A PERIOD OF AT LEAST FORCE 3 WINDS FRIDAY NIGHT INTO SATURDAY. NOT OUT OF THE QUESTION THAT THERE COULD BE A PERIOD OF FORCE 4 WINDS DURING THAT TIME FRAME BUT WILL JUST TREND WINDS UP TO FORCE 3 FOR NOW AND LET LATER SHIFTS CONSIDER A FURTHER INCREASE IN WINDS. AS DAY SHIFT ALLUDED TO WAVES AND POSSIBLY EVEN WINDS SHOULD REACH SMALL CRAFT ADZ CRITERIA THIS WEEKEND OVER THE IL/IN NEAR SHORE WATERS WITH RIP CURRENTS A GOOD BET ON THE INDIANA SHORE AS WELL. IZZI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1145 AM CDT WED JUL 25 2007 .DISCUSSION... 300 AM CDT SLOWLY BUT SURELY...THE CUTOFF LOW OUT TO OUR EAST THAT HAS JAMMED UP OUR WEATHER PATTERN WILL BEGIN PROPAGATING OUT OF THE REGION ON THURSDAY. THE MODEL CONSENSUS THE PAST FEW DAYS HAS BEEN TO BRING THE CUTOFF LOW INTO SOUTHERN MICHIGAN LATE THURSDAY AND TRANSITIONING IT TO AN OPEN WAVE IN SOUTHEASTERN CANADA BY SATURDAY. THE MAIN PUSH THAT IS GOING TO BUDGE THIS ALONG IS THE PACIFIC SYSTEM THAT MADE LANDFALL LATE MONDAY AND IS CURRENTLY CLIMBING ALONG THE PERIPHERY OF THE STRONG MID-LEVEL RIDGE EXTENDING INTO THE HUDSON BAY. THIS WILL HELP TO DEEPEN THE CANADIAN TROF AND THUS PICK UP THE MEANDERING CUTOFF LOW. THIS CUTOFF LOW HAS ACTUALLY BEEN A SAVIOR OF SORTS AS EARLIER FORECAST RUNS...THAT DID NOT HAVE THIS LOW RETROGRADING INTO OUR REGION...HAD THE AMPLIFIED WESTERN RIDGE AXIS DIRECTLY OVER US FOR AN EXTENDED PERIOD OF TIME. THIS PROBABLY WOULD HAVE MEANT HIGH TEMPS IN THE 90S AND DEW POINTS IN THE 70S. THIS LOW HAS KEPT TEMPERATURES AND DEW POINTS FAIRLY SEASONAL...IF NOT A LITTLE BELOW NORMAL. BACK TO THE FORECAST...THE FOCUS OVER THE NEXT FEW DAYS WILL BE ON PRECIP CHANCES. BACKED OFF ON A FEW PERIODS THAT PREVIOUSLY HAD MENTION OF THUNDER AS IT APPEARS THAT THE BEST CHANCE FOR THAT WILL BE WHEN THE ACTUAL CORE OF THE CUTOFF LOW GETS INTO SOUTHERN MICHIGAN AND WHEN THE COLD FRONT DROPS THROUGH ON FRIDAY. WILL HAVE TO MONITOR ANY SHORTWAVES ROTATING ALONG THE MID-LEVEL LOW AS THAT WILL PROVIDE BETTER FOCUS FOR SHOWER DEVELOPMENT. AT THE MOMENT...IT APPEARS AS THE ONLY SHORTWAVE IS THE ONE EXTENDING SOUTHWARD OUT OF THE LOW ALONG THE APPALACHIANS. UPPED POPS FOR FRIDAY AS IT APPEARS THAT THE GULF WILL BE OPEN FOR BUSINESS AND SHOULD SUPPLY ENOUGH MOISTURE TO HELP DEVELOP A LINE OF SHOWERS AND STORMS OUT AHEAD OF THE FRONT. ANY SEVERE POTENTIAL SEEMS MINIMAL AT THIS POINT AS CAPE VALUES ONLY GET TO AROUND 1000 J/KG AND HARDLY ANY WIND SHEAR TO SPEAK OF. MID-LEVEL LAPSE RATES ARE NOT ALL THAT IMPRESSIVE EITHER AS THE MAIN MID-LEVEL HEIGHT FALLS WILL BE WELL NORTH IN CANADA. AS THE FRONT PASSES...SKIES WILL EVENTUALLY CLEAR OUT FOR THE REST OF THE WEEKEND. AS FOR TEMPERATURES...NOT MANY CHANGES MADE TO THE GOING FORECAST. THURSDAY NIGHT INTO FRIDAY WILL LIKELY BE THE WARMEST PORTION OF THE FORECAST PERIOD AS WARM AIR FROM THE WESTERN RIDGE FINALLY ADVECTS INTO THE REGION OUT AHEAD OF THE COLD FRONT. NOT MUCH OF A COLD/DRY PUNCH BEHIND THIS FRONT AS TEMPS WILL REMAIN AROUND NORMAL FOR THIS TIME OF YEAR. HALBACH && .AVIATION... FOR THE 0600 UTC TAFS...FIRST ISSUE WITH THIS MORNINGS TAFS IS HOW TO HANDLE SHOWERS SPROUTING UP OVER LAKE MICHIGAN FROM THE MID LEVEL CLOUD DECK. GIVEN RECENT ACARS SOUNDINGS FROM ORD/RFD FRANKLY RATHER SURPRISED THE SHOWERS HAVE BEEN DEVELOPING AS ROBUSTLY AS THEY HAVE BEEN WITH A PRONOUNCED INVERSIONS AROUND 600MB. WATER VAPOR IMAGERY DOES SHOW A SHEARED VORT LOBE/JET STREAK ROTATING AROUND THE NORTHWEST PERIPHERY OF THE UPPER LOW WHICH INCREASED ASCENT IN ADVANCE OF THIS FEATURE IS PROBABLY THE CAUSE FOR THE RECENT UPSWING IN SHOWER ACTIVITY. WITH ISOLD/WDLY SCT -SHRA LIKELY TO CONTINUE THROUGH AT LEAST THE EARLY AFTERNOON FELT IT WAS PRUDENT TO INCLUDE VCSH AT THE CHGO METRO TERMINALS. OTHER CONCERN...ALBEIT RATHER MINOR CONCERN...IS WITH WINDS WED WITH LAKE BREEZE LIKELY TO DEVELOP. DESPITE FAIRLY EXTENSIVE MID LEVEL DECK YESTERDAY STILL SAW SUFFICIENT DIFFERENTIAL HEATING BETWEEN LAND/WATER FOR LAKE BREEZE TO FORM TUES PM. SEE NO REASON WE WONT SEE A REPEAT PERFORMANCE TODAY WITH LAKE LIKELY TO SPEW OUT ANOTHER LAKE BREEZE DURING THE AFTERNOON. TIMING/STRENGTH OF THE LAKE PUSH AT ORD/MDW WILL LIKELY BE DICTATED LARGELY ON HOW MUCH SUNSHINE AND HOW QUICKLY THE LAND HEATS UP TODAY...AS A FIRST GUESS WENT WITH PERSISTENCE FROM TUES AFTERNOON FOR TIMING STRENGTH. IZZI && .MARINE... 140 AM CDT SHOULD GENERALLY SEE SOUTHERLY WINDS OVER THE OPEN WATERS OF THE LAKE THROUGH FRIDAY MORNING. WHILE GENERAL SYNOPTIC FLOW WILL FAVOR SOUTHERLY WINDS...GRADIENT EXPECTED TO REMAIN WEAK ENOUGH TO ALLOW DEVELOPMENT OF AFTERNOON LAKE BREEZES AND WEAK NIGHTTIME LAND BREEZES OVER THE NEARSHORE WATERS. COLD FRONT STILL SLATED TO DROP DOWN THE LAKE DURING THE DAY FRIDAY AS ANOTHER CANADIAN HIGH BUILDS SOUTHWARD INTO THE GREAT LAKES REGION FRIDAY NIGHT INTO SATURDAY. THIS WEEKENDS HIGH IS PROGGED TO BE WEAKER THAN THE LAST HIGH THAT KICKED UP GALES OVER THE LAKE. DESPITE THIS HIGH BEING A BIT WEAKER...THE LAKE CONTINUES TO WARM AND WITH A MODEST PUSH OF COLD AIR ADVECTION REALLY NOT EXPECTING TO SEE OVERLY STABLE CONDITIONS OVER THE WATER SO WILL PROBABLY SEE A PERIOD OF AT LEAST FORCE 3 WINDS FRIDAY NIGHT INTO SATURDAY. NOT OUT OF THE QUESTION THAT THERE COULD BE A PERIOD OF FORCE 4 WINDS DURING THAT TIME FRAME BUT WILL JUST TREND WINDS UP TO FORCE 3 FOR NOW AND LET LATER SHIFTS CONSIDER A FURTHER INCREASE IN WINDS. AS DAY SHIFT ALLUDED TO WAVES AND POSSIBLY EVEN WINDS SHOULD REACH SMALL CRAFT ADZ CRITERIA THIS WEEKEND OVER THE IL/IN NEAR SHORE WATERS WITH RIP CURRENTS A GOOD BET ON THE INDIANA SHORE AS WELL. IZZI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
937 PM EDT THU JUL 26 2007 .SYNOPSIS... INCREASING HUMIDITY AHEAD OF THE NEXT COLD FRONT WILL INCREASE COVERAGE OF SHOWERS AND THUNDERSTORMS INTO EARLY NEXT WEEK. HIGH PRESSURE BUILDING INTO THE REGION DURING THE MID WEEK IS EXPECTED TO BRING MORE TRANQUIL WEATHER. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... WATER VAPOR LOOP SHOWS AN UPPER LOW SPINNING OVER MICHIGAN...WITH AN UPPER LEVEL SHEAR AXIS SOUTHWEST THROUGH THE PLAINS. A TROUGH IS PUSHING EAST ACROSS SOUTH CENTRAL CANADA. ACARS 400-250MB WIND OBSERVATIONS REVEALS A 60-90KT JET AROUND THE UPPER LOW ACROSS EASTERN MICHIGAN. A 80-110KT WESTERLY JET CARVES A TROUGH ACROSS SOUTH CENTRAL CANADA. 21Z SURFACE ANALYSIS PLACED A 1019MB ANTICYCLONE OFF THE MID ATLANTIC COAST. A WARM FRONT WAS LIFTING NORTHEAST/NORTHWARD ACROSS THE MIDWEST AND CAROLINAS. THE NEXT COLD FRONT WAS PUSHING SOUTHEAST THROUGH THE UPPER MIDWEST. THUNDERSTORM COMPLEX WHICH DEVELOPED ACROSS THE TENNESSEE VALLEY THIS EVENING IN ASSOCIATION WITH LOW LEVEL THETA-E ADVECTION ABOVE THE FRONTAL BOUNDARY TO THE SOUTH IS THE MAIN WEATHER FOCUS IN THE NEAR TERM. EXPECT CONVECTION TO BEGIN TO ROTATE NORTHEAST (BASED ON CIRCULATION AROUND MICHIGAN UPPER LOW) AND AFFECT MAINLY THE WEST AND NORTHWEST FORECAST AREA LATE TONIGHT AND EARLY IN THE MORNING. RAISED POPS INTO THE LIKELY AND DEFINITE CATEGORIES IN THOSE LOCATIONS. FURTHER EAST...EXPECT LACK OF DYNAMICAL FORCING TO PRECLUDE MUCH DEVELOPMENT (ALTHOUGH CANT RULE OUT A FEW SHOWERS OR THUNDERSTORMS AS WARM ADVECTION INCREASES WHICH MAY BE ENOUGH TO FORCE DEVELOPMENT ABOVE MARINE AIRMASS). AT THIS TIME...WILL KEEP THE DRY FORECAST. THERE IS DECENT INSTABILITY ALOFT TONIGHT ACROSS THE WESTERN FORECAST AREA ACCORDING TO THE 18Z NAM/GFS BUFKIT FORECAST SOUNDINGS AND 00Z KRNK RAOB TO WARRANT THUNDER. KRNK RAOB SHOWS STEEP LAPSE RATES BUT TIMING WOULD SUGGEST A MINIMAL SEVERE THUNDERSTORM RISK. THERE HAS BEEN SOME AREAS OF 1-2" IN THE WESTERN FORECAST AREA DURING THE PAST FEW DAYS...ALTHOUGH THIS NEXT COMPLEX IS EXPECTED TO MOVE THROUGH AT A DECENT CLIP. WHILE MOST LOCATIONS EAST OF THE MOUNTAINS ARE CURRENTLY MOSTLY CLEAR...EXPECT CONDITIONS TO CHANGE OVERNIGHT. A MARINE AIRMASS (BUOY OFF DELMARVA IS READING 75/75 WITH A 76 WATER TEMPERATURE) IS EXPECTED TO MOVE ONSHORE OVERNIGHT ON SOUTHEAST FLOW. MOISTURE TRAPPED UNDER SHALLOW NOCTURNAL INVERSION WILL YIELD LOW STRATUS INVADING FROM THE DELMARVA...AND AID IN AREAS OF FOG DEVELOPMENT (THIS IS IMPRESSIVELY SHOWN BY LWX WRF NMM AND ARW HIGH RESOLUTION MODEL RUNS). PATCHY VALLEY FOG DEVELOPMENT IS EXPECTED WEST OF THE BLUE RIDGE WHERE SOME RAIN FELL DURING THE DAY...ESPECIALLY LOCATIONS REMOVED FROM INCOMING CONVECTIVE DEBRIS. POPULATED WITH ETA MOS LOW TEMPERATURES BASED ON RECENT PERFORMANCE AND ADJUSTED FOR LOCAL BIAS. WINDS ARE BASED ON THE 12Z LWX WRF-ARW. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... CONFIDENCE NOT TOO HIGH REGARDING CONVECTIVE EVOLUTION FRIDAY. MUCH WILL DEPEND ON THE AMOUNT OF CONVECTIVE DEBRIS FROM THE INCOMING COMPLEX. THE UPPER LOW WILL BE PICKED UP BY A TROUGH AND SHIFTED INTO THE REGION DURING THE AFTERNOON...WHICH WILL AID IN DYNAMICAL LIFT (SHOULD SUFFICIENT INSTABILITY BE PRESENT). FURTHER EAST...MARINE INFLOW SHOULD PRECLUDE MUCH DEVELOPMENT...ALTHOUGH SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP ON THE EDGE OF THE MARINE AIRMASS BETWEEN THE BLUE RIDGE AND INTERSTATE 95. DESPITE QUESTIONS ABOUT CLOUD COVER...DECIDED TO CONTINUE TO MENTION TEMPERATURES AT OR ABOVE HIGHEST MOS GUIDANCE BASED ON RECENT BIAS. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... FRIDAY NIGHT THROUGH SATURDAY NIGHT...ANOTHER STORM SYSTEM WILL DIVE SOUTHEAST FROM CANADA FRIDAY NIGHT. THIS ALONG WITH THE UPPER LEVEL LOW CURRENTLY LOCATED OVER THE GREAT LAKES WILL BE RESPONSIBLE FOR CARVING OUT A TROUGH OF LOW PRESSURE OVER THE REGION. AT THE SAME TIME LARGE HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL ALLOW FOR A SOUTH-SOUTHWEST FLOW TO BRING PLENTY OF LOW AND MID-LEVEL MOISTURE ALONG WITH SEASONABLY WARM CONDITIONS. MOISTURE ALONG WITH THE TROUGH OF LOW PRESSURE WILL HELP TO TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS WITH THE BEST CHANCE DURING THE AFTERNOON AND EVENING HOURS WEST OF THE BLUE RIDGE. SUNDAY THROUGH MONDAY...THE TROUGH OF LOW PRESSURE WILL REMAIN OVER THE REGION WHILE A COLD FRONT SLOWLY APPROACHES FROM THE GREAT LAKES. HOWEVER...THIS FRONT WILL BE VERY SLOW TO MOVE THROUGH OUR REGION THANKS TO THE STRONG HIGH OVER THE WESTERN ATLANTIC. MODEL GUIDANCE CONTINUES TO SHOW A WAVE OF LOW PRESSURE DEVELOPING ALONG THIS FRONT OVER OUR REGION. THIS COULD RESULT IN MORE WIDESPREAD SHOWER/T-STORM ACTIVITY. MONDAY NIGHT THROUGH THURSDAY NIGHT...THE COLD FRONT WILL FINALLY PUSH EAST BUT IT WILL LIKELY STALL ALONG THE MID ATLANTIC COAST. CURRENT THINKING IS THAT ENOUGH DRY AIR CAN PUSH IN FROM THE NORTHWEST BEHIND THE FRONT FOR DRY CONDITIONS ACROSS MOST LOCATIONS. HOWEVER...GUIDANCE DOES SUGGEST THE DEVELOPMENT OF ANOTHER CUT OFF LOW WITH VERY LITTLE CERTAINTY TO HOW STRONG IT WILL BE AND EXACTLY WHERE. FOR NOW...WE JUST WENT WITH SLIGHT POPS THROUGH THE PERIOD WITH SEASONABLY WARM TEMPERATURES EXPECTED. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... EXPECT SIMILAR IFR CONDITIONS TO DEVELOP FROM THE DELMARVA WESTWARD BY MORNING WITHIN MARINE AIRMASS. PATCHY FOG MAY DEVELOP NEAR MRB/CHO...ESPECIALLY AHEAD OF CONVECTIVE DEBRIS CLOUDS. WHILE TAF FORECAST IS DRY...CONVECTION MAY GET CLOSE TO MRB AND PERHAPS CHO/IAD BY MORNING. WITH NO MODEL GUIDANCE WITH A FIRM GRIP...WILL WAIT UNTIL ABLE TO TIME IN VIA RADAR. CONVECTIVE DEBRIS QUESTIONS PRECLUDE MENTION OF FRIDAY AFTERNOON STORMS AT TIME TIME. MARINE LAYER EXPECTED TO DISPERSE THIS WEEKEND WITH ARRIVAL OF NEXT COLD FRONT. WEATHER IMPACT WILL BE ASSOCIATED WITH INCREASING COVERAGE OF THUNDERSTORMS INTO THE EARLY WORK WEEK. HIGH PRESSURE EXPECTED TO BRING MORE TRANQUIL WEATHER TO THE REGION BY MIDWEEK. && .MARINE... ETA/GFS MOS AND HIGH RESOLUTION MODEL GUIDANCE SUGGEST WINDS WILL REMAIN 10-15KTS OVERNIGHT...BEFORE SLACKENING FRIDAY. AREAS OF LIGHT FOG POSSIBLE AROUND DAY BREAK. CANT RULE OUT ISOLATED STORMS DURING THE DAY FRIDAY. WATCH FOR REDUCED VISIBILITES...AND LOCALLY HIGHER WINDS AND WAVES. INCREASING COVERAGE OF THUNDERSTORMS INTO THE EARLY WORK WEEK AS THE NEXT COLD FRONT ARRIVES IN THE REGION. HIGH PRESSURE EXPECTED TO BRING MORE TRANQUIL WEATHER TO THE REGION BY MIDWEEK. && .TIDES... FAVORABLE SE/E WIND COMPONENT EXPECTED TO CONTINUE INTO MIDWEEK. THIS FLOW COULD STRENGTHEN DEPENDING ON HOW DEEP THE LOW PRESSURE AREA DEVELOPS ALONG THE NEXT COLD FRONT. GIVEN A NEARLY FULL MOON...WILL HAVE TO MONITOR FOR INCREASING POSITIVE WATER DEPARTURES INTO EARLY NEXT WEEK. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...ROGOWSKI NEAR TERM...ROGOWSKI SHORT TERM...ROGOWSKI LONG TERM...LASORSA AVIATION...ROGOWSKI MARINE...ROGOWSKI TIDES...ROGOWSKI
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
114 PM EDT WED JUL 25 2007 UPDATED FOR AVIATION DISCUSSION .DISCUSSION... MAIN FCST ISSUES ARE POSSIBILITY OF ISOLD SHRA/TSRA TODAY AND THEN CONVECTION POTENTIAL WITH COLD FROPA THU NIGHT/FRI MORNING. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW MID/UPPER LEVEL RIDGE OVER THE WRN PLAINS INTO ONTARIO WHILE A MIDLEVEL LOW WAS CENTERED OVER ERN OHIO. A SHORTWAVE DRIFTING S THRU MN HAD GENERATED SOME CONVECTION IN SW MN EARLIER IN THE NIGHT. RIDGE TO THE W HAS RESULTED IN OPPRESSIVE HEAT OVER MT/WY INTO THE DAKOTAS/MANITOBA/NRN ONTARIO. HIGH TEMPS YESTERDAY WERE AOA 100F OVER THE WRN DAKOTAS WHILE MID 90S DOMINATED MUCH OF NRN ONTARIO. CLOSER TO HOME...A COUPLE OF SHRA MANAGED TO DEVELOP LAST EVENING OVER THE CNTRL FCST AREA...BUT THE OVERNIGHT HAS BEEN QUIET WITH SOME PATCHY FOG DEVELOPING. DENSER FOG APPEARS TO BE FORMING OVER THE ERN HALF OF THE FCST AREA. VIS SATELLITE IMAGERY OVER THE LAST 2 DAYS SHOWS THAT A SMALL PORTION OF THE MASSIVE AMOUNT OF SMOKE PRODUCED BY FOREST FIRES IN NRN MANITOBA/SASKATCHEWAN IN RECENT DAYS IS FINDING ITS WAY AROUND THE MIDLEVEL RIDGE INTO THE UPPER GREAT LAKES. MAY SEE SOME OF THIS ELEVATED SMOKE OVER PORTIONS OF MAINLY THE ERN FCST AREA TODAY. AS WAS THE CASE THE LAST 2 DAYS...CONVECTION POTENTIAL IS THE MAIN QUESTION FOR THE FIRST PERIOD OF FCST. ALOFT...MIDLEVEL LOW OVER ERN OHIO WILL DRIFT TO NEAR DETROIT BY EVENING. THERE IS NO EVIDENCE OF ANY SHORTWAVES ROTATING AROUND LOW TO AFFECT THE FCST AREA TODAY...AND THE NW FLANK OF MIDLEVEL LOW WAS RELATIVELY PCPN FREE YESTERDAY. SO...DO NOT EXPECT THE MIDLEVEL LOW TO INFLUENCE CONVECTIVE POTENTIAL HERE TODAY. TAKING A LOOK AT YESTERDAYS SITUATION...00Z KGRB SOUNDING SHOWED NO CAP WITH SBCAPE OF 2200J/KG. EVEN LOWERING SFC TD INTO THE MID 60S...ENVIRONMENT WAS NOT CAPPED. EVENING TAMDAR SOUNDING FROM KSAW SHOWED SIMILAR NON-CAPPED ENVIRONMENT. DESPITE THIS...CONVECTION WAS VERY ISOLATED YESTERDAY AFTN/EVENING. FCST SOUNDINGS TODAY SHOW A SIMILAR SETUP TO YESTERDAY. MODIFIED NAM/GFS FCST SOUNDINGS FOR A SFC T/TD IN THE UPPER 80S/UPPER 60S SUGGEST PARCELS WILL BE ABLE TO SNEEK BY THE CAP THIS AFTN WITH SBCAPE GENERALLY IN THE 1500-2000J/KG RANGE. LAKE BREEZE BOUNDARIES WILL DEVELOP ALTHOUGH THE ONE OFF LAKE SUPERIOR WILL NOT BE AS PRONOUNCED WITH INLAND PUSH COMPARED TO YESTERDAY. IN FACT...IT MAY JUST HANG ALONG THE LAKESHORE. SO...THERE WILL BE A LOW-LEVEL FOCUSING MECHANISM...BUT WEAKER THAN YESTERDAY. HOWEVER...GIVEN THE LACK OF CONVECTION YESTERDAY WITH CONDITIONS SOMEWHAT MORE FAVORABLE THAN WHAT IS ANTICIPATED TODAY...WILL NOT INCLUDE A MENTION OF SHRA/TSRA. MIDLEVEL LOW WILL CONTINUE TO DRIFT SLOWLY WWD TONIGHT...BUT WITH NO SHORTWAVES SWINGING AROUND IT INTO THE UPPER LAKES...IT SHOULD BE A QUIET NIGHT ACROSS THE FCST AREA. CONDITIONS LOOK FAVORABLE TONIGHT FOR SOME FOG DEVELOPMENT AGAIN. HOWEVER...IT SHOULD BE LESS WIDESPREAD/LESS DENSE THAN RECENT NIGHTS WITH A BIT MORE WIND. WILL ONLY MENTION PATCHY FOG OVER THE SW PORTION OF FCST AREA WHERE WINDS WILL BE LIGHTEST. THU...MIDLEVEL LOW WILL MEANDER OVER SRN LWR MI...BUT OF MORE IMPORTANCE IS SHORTWAVE MOVING E ACROSS SCNTRL CANADA WHICH WILL SUPPRESS THE MIDLEVEL RIDGE. THIS SHORTWAVE WILL TRACK OVER ONTARIO AND THE UPPER GREAT LAKES THU NIGHT AND WILL PICK UP MIDLEVEL LOW OVER LWR MI. MODELS ARE IN EXCELLENT AGREEMENT SHOWING COLD FRONT ASSOCIATED WITH SHORTWAVE KNOCKING ON THE DOOR OF WRN UPPER MI AT 00Z FRI. THIS IS CONSISTENT WITH PREVIOUS MODEL RUNS. PROXIMITY OF FRONT SUGGESTS CHC POPS ARE WARRANTED OVER THE W IN THE AFTN. BEST DEEP LAYER FORCING/HEIGHT FALLS ASSOCIATED WITH SHORTWAVE WILL PASS THRU ONTARIO WHILE BEST INSTABILITY WILL TRACK SW AND S OF THE FCST AREA THU NIGHT. SO...THERE MAY BE A TENDENCY FOR THE MORE SIGNIFICANT PCPN TO SPLIT AROUND THE FCST AREA TO THE N AND S THOUGH THE 00Z MODEL RUNS DON`T EXPLICITLY SHOW THIS. HAVE THUS MAINTAINED 40-50 POPS RATHER THAN GOING LIKELY JUST YET. DEEP LAYER SHEAR GENERALLY UNDER 30KT AND HIGH FREEZING LEVELS SHOULD PRECLUDE SVR THREAT. SPC CONCURS AS UPPER MI IS NOT OUTLOOKED FOR A SLIGHT RISK OF SVR ATTM. OTHERWISE...WITH PRECIPITABLE WATER JUST OVER 2 INCHES (AROUND 225PCT OF NORMAL) AND DEEP WARM CLOUD DEPTH (FREEZING LEVEL AROUND 14KFT)...LOCALLY HVY RAINFALL IS POSSIBLE. DECENT/WIDESPREAD RAIN IS CERTAINLY NEEDED...SO HOPEFULLY THIS SYSTEM WILL PROVIDE IT. WITH COLD FRONT EXITING THE ERN FCST AREA FRI MORNING...LINGERING POPS IN THE MORNING LOOK FINE FOR THE CNTRL AND E. DRIER AND SLIGHTLY COOLER AIR WILL THEN SETTLE OVER THE AREA BEHIND THE FRONT. OVER THE WEEKEND THRU AT LEAST EARLY NEXT WEEK...MEDIUM RANGE MODELS SHOW MID/UPPER LEVEL RIDGE REBUILDING OVER THE WRN PLAINS INTO SCNTRL CANADA AND THEN GRADUALLY EXPANDING EWD. PATTERN WILL NOT BE FAVORABLE FOR PCPN WITH JET BECOMING DISPLACED WELL N OF UPPER MI. SO...AN EXTENDED PERIOD OF DRY WEATHER WILL CONTINUE FOR THE FORESEEABLE FUTURE. IN FACT...CPC 6-10 AND 8-14 DAY OUTLOOKS HAVE THE UPPER GREAT LAKES REGION UNDER BLO NORMAL PCPN. IF WIDESPREAD RAINFALL DOES NOT OCCUR THU NIGHT...IT MAY BE QUITE A WHILE BEFORE ANOTHER OPPORTUNITY ARISES. ALTHOUGH IT WILL BECOME WARMER AGAIN OVER THE WEEKEND AND NEXT WEEK...IT DOES NOT LOOK LIKE THE HEAT WILL GET OUT OF CONTROL. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... MAIN CONCERN REMAINS FOG POTENTIAL TONIGHT AT BOTH SITES. VERY DRY AIR AT MID-LEVELS WILL LIKELY PREVENT SHRA/TSRA FROM OCCURRING TODAY AT BOTH TAF SITES AS VFR CONDITIONS PREVAIL. LINGERING MOIST DEW POINTS WILL ALLOW FOR FOG TO REDEVELOP AGAIN LATE THIS EVENING OR OVERNIGHT WITH OCCASIONAL IFR VSBYS AT BOTH TAF SITES. LOOK FOR FOG TO DISSIPATE WITH DIURNAL HEATING BY 14Z. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... IR SATELLITE SHOWING AREAS OF FOG OVER MUCH OF LAKE SUPERIOR. FOG SHOULD CONTINUE TO BE A PROBLEM ON THE LAKE THROUGH TODAY AS HIGH DEW POINTS ARE MOVING ACROSS THE COLD WATER. FOG WILL CONTINUE TO BE A PROBLEM OVER THE LAKE THROUGH FRIDAY MORNING AS DEW POINTS WILL REMAIN HIGH. WINDS WILL REMAIN LIGHT AND NO GALES OR LARGE WAVES EXPECTED ANYTIME SOON. A COLD FRONT WILL CROSS LAKE SUPERIOR THURSDAY NIGHT. SOUTHEAST TO SOUTH WINDS AHEAD OF FRONT MAY INCREASE TO NEAR 15 KT OVER EASTERN LAKE SUPERIOR WEDNESDAY NIGHT AND THURSDAY. AFTER FRONTAL PASSAGE...NORTHERLY WINDS MAY REACH 15KT FOR A TIME OVER MUCH OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...ROLFSON AVIATION...VOSS MARINE...DLG
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
855 AM EDT WED JUL 25 2007 UPDATED FOR AVIATION DISCUSSION .DISCUSSION... MAIN FCST ISSUES ARE POSSIBILITY OF ISOLD SHRA/TSRA TODAY AND THEN CONVECTION POTENTIAL WITH COLD FROPA THU NIGHT/FRI MORNING. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW MID/UPPER LEVEL RIDGE OVER THE WRN PLAINS INTO ONTARIO WHILE A MIDLEVEL LOW WAS CENTERED OVER ERN OHIO. A SHORTWAVE DRIFTING S THRU MN HAD GENERATED SOME CONVECTION IN SW MN EARLIER IN THE NIGHT. RIDGE TO THE W HAS RESULTED IN OPPRESSIVE HEAT OVER MT/WY INTO THE DAKOTAS/MANITOBA/NRN ONTARIO. HIGH TEMPS YESTERDAY WERE AOA 100F OVER THE WRN DAKOTAS WHILE MID 90S DOMINATED MUCH OF NRN ONTARIO. CLOSER TO HOME...A COUPLE OF SHRA MANAGED TO DEVELOP LAST EVENING OVER THE CNTRL FCST AREA...BUT THE OVERNIGHT HAS BEEN QUIET WITH SOME PATCHY FOG DEVELOPING. DENSER FOG APPEARS TO BE FORMING OVER THE ERN HALF OF THE FCST AREA. VIS SATELLITE IMAGERY OVER THE LAST 2 DAYS SHOWS THAT A SMALL PORTION OF THE MASSIVE AMOUNT OF SMOKE PRODUCED BY FOREST FIRES IN NRN MANITOBA/SASKATCHEWAN IN RECENT DAYS IS FINDING ITS WAY AROUND THE MIDLEVEL RIDGE INTO THE UPPER GREAT LAKES. MAY SEE SOME OF THIS ELEVATED SMOKE OVER PORTIONS OF MAINLY THE ERN FCST AREA TODAY. AS WAS THE CASE THE LAST 2 DAYS...CONVECTION POTENTIAL IS THE MAIN QUESTION FOR THE FIRST PERIOD OF FCST. ALOFT...MIDLEVEL LOW OVER ERN OHIO WILL DRIFT TO NEAR DETROIT BY EVENING. THERE IS NO EVIDENCE OF ANY SHORTWAVES ROTATING AROUND LOW TO AFFECT THE FCST AREA TODAY...AND THE NW FLANK OF MIDLEVEL LOW WAS RELATIVELY PCPN FREE YESTERDAY. SO...DO NOT EXPECT THE MIDLEVEL LOW TO INFLUENCE CONVECTIVE POTENTIAL HERE TODAY. TAKING A LOOK AT YESTERDAYS SITUATION...00Z KGRB SOUNDING SHOWED NO CAP WITH SBCAPE OF 2200J/KG. EVEN LOWERING SFC TD INTO THE MID 60S...ENVIRONMENT WAS NOT CAPPED. EVENING TAMDAR SOUNDING FROM KSAW SHOWED SIMILAR NON-CAPPED ENVIRONMENT. DESPITE THIS...CONVECTION WAS VERY ISOLATED YESTERDAY AFTN/EVENING. FCST SOUNDINGS TODAY SHOW A SIMILAR SETUP TO YESTERDAY. MODIFIED NAM/GFS FCST SOUNDINGS FOR A SFC T/TD IN THE UPPER 80S/UPPER 60S SUGGEST PARCELS WILL BE ABLE TO SNEEK BY THE CAP THIS AFTN WITH SBCAPE GENERALLY IN THE 1500-2000J/KG RANGE. LAKE BREEZE BOUNDARIES WILL DEVELOP ALTHOUGH THE ONE OFF LAKE SUPERIOR WILL NOT BE AS PRONOUNCED WITH INLAND PUSH COMPARED TO YESTERDAY. IN FACT...IT MAY JUST HANG ALONG THE LAKESHORE. SO...THERE WILL BE A LOW-LEVEL FOCUSING MECHANISM...BUT WEAKER THAN YESTERDAY. HOWEVER...GIVEN THE LACK OF CONVECTION YESTERDAY WITH CONDITIONS SOMEWHAT MORE FAVORABLE THAN WHAT IS ANTICIPATED TODAY...WILL NOT INCLUDE A MENTION OF SHRA/TSRA. MIDLEVEL LOW WILL CONTINUE TO DRIFT SLOWLY WWD TONIGHT...BUT WITH NO SHORTWAVES SWINGING AROUND IT INTO THE UPPER LAKES...IT SHOULD BE A QUIET NIGHT ACROSS THE FCST AREA. CONDITIONS LOOK FAVORABLE TONIGHT FOR SOME FOG DEVELOPMENT AGAIN. HOWEVER...IT SHOULD BE LESS WIDESPREAD/LESS DENSE THAN RECENT NIGHTS WITH A BIT MORE WIND. WILL ONLY MENTION PATCHY FOG OVER THE SW PORTION OF FCST AREA WHERE WINDS WILL BE LIGHTEST. THU...MIDLEVEL LOW WILL MEANDER OVER SRN LWR MI...BUT OF MORE IMPORTANCE IS SHORTWAVE MOVING E ACROSS SCNTRL CANADA WHICH WILL SUPPRESS THE MIDLEVEL RIDGE. THIS SHORTWAVE WILL TRACK OVER ONTARIO AND THE UPPER GREAT LAKES THU NIGHT AND WILL PICK UP MIDLEVEL LOW OVER LWR MI. MODELS ARE IN EXCELLENT AGREEMENT SHOWING COLD FRONT ASSOCIATED WITH SHORTWAVE KNOCKING ON THE DOOR OF WRN UPPER MI AT 00Z FRI. THIS IS CONSISTENT WITH PREVIOUS MODEL RUNS. PROXIMITY OF FRONT SUGGESTS CHC POPS ARE WARRANTED OVER THE W IN THE AFTN. BEST DEEP LAYER FORCING/HEIGHT FALLS ASSOCIATED WITH SHORTWAVE WILL PASS THRU ONTARIO WHILE BEST INSTABILITY WILL TRACK SW AND S OF THE FCST AREA THU NIGHT. SO...THERE MAY BE A TENDENCY FOR THE MORE SIGNIFICANT PCPN TO SPLIT AROUND THE FCST AREA TO THE N AND S THOUGH THE 00Z MODEL RUNS DON`T EXPLICITLY SHOW THIS. HAVE THUS MAINTAINED 40-50 POPS RATHER THAN GOING LIKELY JUST YET. DEEP LAYER SHEAR GENERALLY UNDER 30KT AND HIGH FREEZING LEVELS SHOULD PRECLUDE SVR THREAT. SPC CONCURS AS UPPER MI IS NOT OUTLOOKED FOR A SLIGHT RISK OF SVR ATTM. OTHERWISE...WITH PRECIPITABLE WATER JUST OVER 2 INCHES (AROUND 225PCT OF NORMAL) AND DEEP WARM CLOUD DEPTH (FREEZING LEVEL AROUND 14KFT)...LOCALLY HVY RAINFALL IS POSSIBLE. DECENT/WIDESPREAD RAIN IS CERTAINLY NEEDED...SO HOPEFULLY THIS SYSTEM WILL PROVIDE IT. WITH COLD FRONT EXITING THE ERN FCST AREA FRI MORNING...LINGERING POPS IN THE MORNING LOOK FINE FOR THE CNTRL AND E. DRIER AND SLIGHTLY COOLER AIR WILL THEN SETTLE OVER THE AREA BEHIND THE FRONT. OVER THE WEEKEND THRU AT LEAST EARLY NEXT WEEK...MEDIUM RANGE MODELS SHOW MID/UPPER LEVEL RIDGE REBUILDING OVER THE WRN PLAINS INTO SCNTRL CANADA AND THEN GRADUALLY EXPANDING EWD. PATTERN WILL NOT BE FAVORABLE FOR PCPN WITH JET BECOMING DISPLACED WELL N OF UPPER MI. SO...AN EXTENDED PERIOD OF DRY WEATHER WILL CONTINUE FOR THE FORESEEABLE FUTURE. IN FACT...CPC 6-10 AND 8-14 DAY OUTLOOKS HAVE THE UPPER GREAT LAKES REGION UNDER BLO NORMAL PCPN. IF WIDESPREAD RAINFALL DOES NOT OCCUR THU NIGHT...IT MAY BE QUITE A WHILE BEFORE ANOTHER OPPORTUNITY ARISES. ALTHOUGH IT WILL BECOME WARMER AGAIN OVER THE WEEKEND AND NEXT WEEK...IT DOES NOT LOOK LIKE THE HEAT WILL GET OUT OF CONTROL. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... MAIN CONCERN REMAINS ON FOG POTENTIAL AT BOTH SITES. DAYTIME HEATING SHOULD DISSIPATE THE FOG AT BOTH TAF SITES BY 14Z ...BUT THEN AN MVFR CLOUD COULD FORM SIMILAR TO YESTERDAY MORNING...BEFORE CEILINGS RISE TO VFR EARLY IN THE AFTERNOON. LINGERING MOIST DEW POINTS WILL ALLOW FOR FOG TO REDEVELOP AGAIN LATE THIS EVENING OR OVERNIGHT WITH OCCASIONAL IFR VSBYS AT BOTH TAF SITES. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... IR SATELLITE SHOWING AREAS OF FOG OVER MUCH OF LAKE SUPERIOR. FOG SHOULD CONTINUE TO BE A PROBLEM ON THE LAKE THROUGH TODAY AS HIGH DEW POINTS ARE MOVING ACROSS THE COLD WATER. FOG WILL CONTINUE TO BE A PROBLEM OVER THE LAKE THROUGH FRIDAY MORNING AS DEW POINTS WILL REMAIN HIGH. WINDS WILL REMAIN LIGHT AND NO GALES OR LARGE WAVES EXPECTED ANYTIME SOON. A COLD FRONT WILL CROSS LAKE SUPERIOR THURSDAY NIGHT. SOUTHEAST TO SOUTH WINDS AHEAD OF FRONT MAY INCREASE TO NEAR 15 KT OVER EASTERN LAKE SUPERIOR WEDNESDAY NIGHT AND THURSDAY. AFTER FRONTAL PASSAGE...NORTHERLY WINDS MAY REACH 15KT FOR A TIME OVER MUCH OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...ROLFSON AVIATION...VOSS MARINE...DLG
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
419 AM EDT WED JUL 25 2007 .DISCUSSION... MAIN FCST ISSUES ARE POSSIBILITY OF ISOLD SHRA/TSRA TODAY AND THEN CONVECTION POTENTIAL WITH COLD FROPA THU NIGHT/FRI MORNING. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW MID/UPPER LEVEL RIDGE OVER THE WRN PLAINS INTO ONTARIO WHILE A MIDLEVEL LOW WAS CENTERED OVER ERN OHIO. A SHORTWAVE DRIFTING S THRU MN HAD GENERATED SOME CONVECTION IN SW MN EARLIER IN THE NIGHT. RIDGE TO THE W HAS RESULTED IN OPPRESSIVE HEAT OVER MT/WY INTO THE DAKOTAS/MANITOBA/NRN ONTARIO. HIGH TEMPS YESTERDAY WERE AOA 100F OVER THE WRN DAKOTAS WHILE MID 90S DOMINATED MUCH OF NRN ONTARIO. CLOSER TO HOME...A COUPLE OF SHRA MANAGED TO DEVELOP LAST EVENING OVER THE CNTRL FCST AREA...BUT THE OVERNIGHT HAS BEEN QUIET WITH SOME PATCHY FOG DEVELOPING. DENSER FOG APPEARS TO BE FORMING OVER THE ERN HALF OF THE FCST AREA. VIS SATELLITE IMAGERY OVER THE LAST 2 DAYS SHOWS THAT A SMALL PORTION OF THE MASSIVE AMOUNT OF SMOKE PRODUCED BY FOREST FIRES IN NRN MANITOBA/SASKATCHEWAN IN RECENT DAYS IS FINDING ITS WAY AROUND THE MIDLEVEL RIDGE INTO THE UPPER GREAT LAKES. MAY SEE SOME OF THIS ELEVATED SMOKE OVER PORTIONS OF MAINLY THE ERN FCST AREA TODAY. AS WAS THE CASE THE LAST 2 DAYS...CONVECTION POTENTIAL IS THE MAIN QUESTION FOR THE FIRST PERIOD OF FCST. ALOFT...MIDLEVEL LOW OVER ERN OHIO WILL DRIFT TO NEAR DETROIT BY EVENING. THERE IS NO EVIDENCE OF ANY SHORTWAVES ROTATING AROUND LOW TO AFFECT THE FCST AREA TODAY...AND THE NW FLANK OF MIDLEVEL LOW WAS RELATIVELY PCPN FREE YESTERDAY. SO...DO NOT EXPECT THE MIDLEVEL LOW TO INFLUENCE CONVECTIVE POTENTIAL HERE TODAY. TAKING A LOOK AT YESTERDAYS SITUATION...00Z KGRB SOUNDING SHOWED NO CAP WITH SBCAPE OF 2200J/KG. EVEN LOWERING SFC TD INTO THE MID 60S...ENVIRONMENT WAS NOT CAPPED. EVENING TAMDAR SOUNDING FROM KSAW SHOWED SIMILAR NON-CAPPED ENVIRONMENT. DESPITE THIS...CONVECTION WAS VERY ISOLATED YESTERDAY AFTN/EVENING. FCST SOUNDINGS TODAY SHOW A SIMILAR SETUP TO YESTERDAY. MODIFIED NAM/GFS FCST SOUNDINGS FOR A SFC T/TD IN THE UPPER 80S/UPPER 60S SUGGEST PARCELS WILL BE ABLE TO SNEEK BY THE CAP THIS AFTN WITH SBCAPE GENERALLY IN THE 1500-2000J/KG RANGE. LAKE BREEZE BOUNDARIES WILL DEVELOP ALTHOUGH THE ONE OFF LAKE SUPERIOR WILL NOT BE AS PRONOUNCED WITH INLAND PUSH COMPARED TO YESTERDAY. IN FACT...IT MAY JUST HANG ALONG THE LAKESHORE. SO...THERE WILL BE A LOW-LEVEL FOCUSING MECHANISM...BUT WEAKER THAN YESTERDAY. HOWEVER...GIVEN THE LACK OF CONVECTION YESTERDAY WITH CONDITIONS SOMEWHAT MORE FAVORABLE THAN WHAT IS ANTICIPATED TODAY...WILL NOT INCLUDE A MENTION OF SHRA/TSRA. MIDLEVEL LOW WILL CONTINUE TO DRIFT SLOWLY WWD TONIGHT...BUT WITH NO SHORTWAVES SWINGING AROUND IT INTO THE UPPER LAKES...IT SHOULD BE A QUIET NIGHT ACROSS THE FCST AREA. CONDITIONS LOOK FAVORABLE TONIGHT FOR SOME FOG DEVELOPMENT AGAIN. HOWEVER...IT SHOULD BE LESS WIDESPREAD/LESS DENSE THAN RECENT NIGHTS WITH A BIT MORE WIND. WILL ONLY MENTION PATCHY FOG OVER THE SW PORTION OF FCST AREA WHERE WINDS WILL BE LIGHTEST. THU...MIDLEVEL LOW WILL MEANDER OVER SRN LWR MI...BUT OF MORE IMPORTANCE IS SHORTWAVE MOVING E ACROSS SCNTRL CANADA WHICH WILL SUPPRESS THE MIDLEVEL RIDGE. THIS SHORTWAVE WILL TRACK OVER ONTARIO AND THE UPPER GREAT LAKES THU NIGHT AND WILL PICK UP MIDLEVEL LOW OVER LWR MI. MODELS ARE IN EXCELLENT AGREEMENT SHOWING COLD FRONT ASSOCIATED WITH SHORTWAVE KNOCKING ON THE DOOR OF WRN UPPER MI AT 00Z FRI. THIS IS CONSISTENT WITH PREVIOUS MODEL RUNS. PROXIMITY OF FRONT SUGGESTS CHC POPS ARE WARRANTED OVER THE W IN THE AFTN. BEST DEEP LAYER FORCING/HEIGHT FALLS ASSOCIATED WITH SHORTWAVE WILL PASS THRU ONTARIO WHILE BEST INSTABILITY WILL TRACK SW AND S OF THE FCST AREA THU NIGHT. SO...THERE MAY BE A TENDENCY FOR THE MORE SIGNIFICANT PCPN TO SPLIT AROUND THE FCST AREA TO THE N AND S THOUGH THE 00Z MODEL RUNS DON`T EXPLICITLY SHOW THIS. HAVE THUS MAINTAINED 40-50 POPS RATHER THAN GOING LIKELY JUST YET. DEEP LAYER SHEAR GENERALLY UNDER 30KT AND HIGH FREEZING LEVELS SHOULD PRECLUDE SVR THREAT. SPC CONCURS AS UPPER MI IS NOT OUTLOOKED FOR A SLIGHT RISK OF SVR ATTM. OTHERWISE...WITH PRECIPITABLE WATER JUST OVER 2 INCHES (AROUND 225PCT OF NORMAL) AND DEEP WARM CLOUD DEPTH (FREEZING LEVEL AROUND 14KFT)...LOCALLY HVY RAINFALL IS POSSIBLE. DECENT/WIDESPREAD RAIN IS CERTAINLY NEEDED...SO HOPEFULLY THIS SYSTEM WILL PROVIDE IT. WITH COLD FRONT EXITING THE ERN FCST AREA FRI MORNING...LINGERING POPS IN THE MORNING LOOK FINE FOR THE CNTRL AND E. DRIER AND SLIGHTLY COOLER AIR WILL THEN SETTLE OVER THE AREA BEHIND THE FRONT. OVER THE WEEKEND THRU AT LEAST EARLY NEXT WEEK...MEDIUM RANGE MODELS SHOW MID/UPPER LEVEL RIDGE REBUILDING OVER THE WRN PLAINS INTO SCNTRL CANADA AND THEN GRADUALLY EXPANDING EWD. PATTERN WILL NOT BE FAVORABLE FOR PCPN WITH JET BECOMING DISPLACED WELL N OF UPPER MI. SO...AN EXTENDED PERIOD OF DRY WEATHER WILL CONTINUE FOR THE FORESEEABLE FUTURE. IN FACT...CPC 6-10 AND 8-14 DAY OUTLOOKS HAVE THE UPPER GREAT LAKES REGION UNDER BLO NORMAL PCPN. IF WIDESPREAD RAINFALL DOES NOT OCCUR THU NIGHT...IT MAY BE QUITE A WHILE BEFORE ANOTHER OPPORTUNITY ARISES. ALTHOUGH IT WILL BECOME WARMER AGAIN OVER THE WEEKEND AND NEXT WEEK...IT DOES NOT LOOK LIKE THE HEAT WILL GET OUT OF CONTROL. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... MAIN CONCERN REMAINS ON FOG POTENTIAL AT BOTH SITES. FOR CMX...SO FAR THE ONLY FOG THAT HAS FORMED APPEARS TO BE RADIATIONALLY DRIVEN...WHICH MAKES SENSE WITHOUT A STRONG WIND. PLUS...WITH THE LACK OF FOG ON EASTERN LAKE SUPERIOR...THINK MUCH OF THE FOG THROUGH THE OVERNIGHT HOURS WILL REMAIN RADIATIONAL...WHICH MEANS IT SHOULD QUICKLY DISSIPATE ONCE THE SUN POPS UP. GIVEN THE LACK OF RAINFALL RECENTLY...HAVE NOT THROWN IN ANY VISIBILITIES LESS THAN MVFR...BUT WILL NEED TO BE WATCHED THROUGH THE OVERNIGHT HOURS. VFR CONDITIONS EXPECTED THEN AFTER SUNRISE...WITH THE TYPICAL LAKE BREEZE DURING THE DAY AND LAND BREEZE DEVELOPING IN THE EVENING. AT SAW...RADIATION FOG SHOULD DEVELOP SHORTLY WITH THE TEMPERATURE APPROACHING THE DEWPOINT. BOTH CMX AND ISQ ALREADY HAVE SOME FOG. LEFT THE POSSIBILITY FOR VISIBILITIES TO DROP TO IFR...MOSTLY DUE TO CLIMATOLOGY OF RADIATION FOG CASES. A LACK OF RECENT RAINFALL SHOULD KEEP THE VISIBILITY FROM DROPPING LOWER. DAYTIME HEATING WILL DISSIPATE THE FOG...BUT THEN COULD GENERATE AN MVFR CLOUD DECK AS IT DID YESTERDAY MORNING SINCE THE AIRMASS REMAINS ABOUT THE SAME. CEILINGS SHOULD THEN RISE TO VFR EARLY IN THE AFTERNOON WITH CONTINUED SUNSHINE. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... IR SATELLITE SHOWING AREAS OF FOG OVER MUCH OF LAKE SUPERIOR. FOG SHOULD CONTINUE TO BE A PROBLEM ON THE LAKE THROUGH TODAY AS HIGH DEW POINTS ARE MOVING ACROSS THE COLD WATER. FOG WILL CONTINUE TO BE A PROBLEM OVER THE LAKE THROUGH FRIDAY MORNING AS DEW POINTS WILL REMAIN HIGH. WINDS WILL REMAIN LIGHT AND NO GALES OR LARGE WAVES EXPECTED ANYTIME SOON. A COLD FRONT WILL CROSS LAKE SUPERIOR THURSDAY NIGHT. SOUTHEAST TO SOUTH WINDS AHEAD OF FRONT MAY INCREASE TO NEAR 15 KT OVER EASTERN LAKE SUPERIOR WEDNESDAY NIGHT AND THURSDAY. AFTER FRONTAL PASSAGE...NORTHERLY WINDS MAY REACH 15KT FOR A TIME OVER MUCH OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...ROLFSON AVIATION...AJ MARINE...DLG
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
230 PM CDT WED JUL 25 2007 .DISCUSSION... MAIN CONCERNS IN THE SHORT TERM PORTIONS OF THE FORECAST REMAIN WITH TEMPERATURES AS WELL AS PRECIPITATION CHANCES BOTH THIS EVENING AND ALSO AT THE END OF THE WEEK. WATER VAPOR IMAGERY AND PROFILER NETWORK FROM THIS AFTERNOON CONTINUE TO SHOW WEAK MID-LVL VORT MAX ACROSS NORTHEASTERN NEBRASKA. IN ADDITION...STRONG DIURNAL HEATING ACROSS THE AREA HAS ALLOWED TYPICAL DAYTIME CU FIELD TO FORM OVER MUCH OF THE CWA. GIVEN THE SITUATION...WOULD NORMALLY THINK WE WOULD HAVE A BETTER CHANCE OF ISOLATED CONVECTION POPPING ESPECIALLY ACROSS THE EXTREME WESTERN GRIDS. HOWEVER...PERUSING THROUGH 12Z UPR AIR SOUNDINGS AND MORE RECENT TAMDAR SOUNDINGS SHOWS A FAIRLY STOUT MID-LVL WARM POCKET THAT IS SQUELCHING THE CU FIELD GROWTH AS IT FORMS. HOWEVER...GIVEN SLIGHT POOLING OF MOISTURE ALONG AND WEST OF THE MISSOURI RIVER VALLEY...WILL NOT RULE OUT THE POSSIBILITY OF ISO-TSRA LATE THIS AFTERNOON AND EARLY THIS EVENING. HOWEVER..BEST Q-VECTOR CONVERGENCE AND UPR LVL SUPPORT IN GENERAL WILL REMAIN OVER CENTRAL KANSAS. BY THURSDAY...H85 THERMAL RIDGE WILL FINALLY BEGIN TO PUSH EVER SO SLOWLY EASTWARD. GIVEN H85 TEMPS A DEGREE OR TWO WARMER THAN THOSE OF TODAY...BUMPED TEMPS UP A HAIR ACROSS THE NORTHWEST...OTHERWISE ONGOING MAX T GRID LOOKED FINE TO ME. OUR ATTENTION WILL THEN TURN TO A POTENT SHORTWAVE OVERTOPPING THE RIDGE ALONG THE BRITISH COLUMBIA/ALBERTA BORDER. THIS WAVE WILL PUSH EASTWARD DURING THE DAY THURSDAY...PUSHING A COLD FRONT ACROSS THE NORTHERN PLAINS. THURSDAY NIGHT...AS AFOREMENTIONED WAVE CONTINUES ITS EASTWARD PUSH...CONVECTION WILL BECOME POSSIBLE ACROSS SOUTHERN SD...NORTHERN NE...AND SOUTHERN MN. THIS CONVECTION WILL LIKELY HELP PUSH THE FRONTAL BOUNDARY TOWARDS THE NORTHERN PORTIONS OF THE CWA BY 12Z FRIDAY. THIS BEING SAID...FELT THE NAM WAS BEING A LITTLE TO AGRESSIVE IN GENERATING CONVECTION GIVEN THE MID-LVL CAP ACROSS THE NORTHERN PLAINS...AND SUBSEQUENTLY TOO AGRESSIVE IN PUSHING THE FRONT SOUTHWARD. FOLLOWED THE SLIGHTLY SLOWER GFS...WITH DYING ACTIVITY JUST REACHING THE NORTHERN CWA BY FRIDAY MORNING. IT SHOULD BE NOTED THAT MOST GUIDANCE WAS SLIGHTLY FASTER THIS MORNING...AND POPS HAVE BEEN ADJUSTED ACCORDINGLY. CONVECTION CHANCES ON FRIDAY LOOK TO BE HIGHLY DEPENDANT ON WHAT HAPPENS THURSDAY NIGHT...AS A SIMILAR SITUATION TO THAT OF LAST WEEK MAY OCCUR. WITH MAIN SHORTWAVE ENERGY FOCUSED FURTHER TO THE NORTHEAST OF THE AREA AND SFC CONVERGENCE OUR MAIN FORCING METHOD...WE MAY NEED SOME SORT OF AN MCV OR CONVECTIVELY INDUCED VORT MAX TO MAKE REGENERATION POSSIBLE LATER DURING THE DAY. CLOUD COVER COULD ALSO BECOME AN ISSUE AND WOULD LIKELY LIMIT INSTABILITY AHEAD OF THE FRONT. AS A RESULT...STILL FEEL THAT SCATTERED COVERAGE/CHANCE POPS WOULD BE WARRANTED GIVEN THE UNCERTAINTIES IN THE FORECAST. IF THE STARS DO ALIGN AND WE ARE ABLE TO REGENERATE CONVECTION ALONG THE FRONT...FREEZING LEVELS AOA 14-15K WILL LIMIT HAIL GROWTH POTENTIAL...AND WITH RELATIVELY WEAK UNIDIRECTIONAL FLOW ALOFT...DAMAGING WINDS AND LOCALLY HEAVY RAIN WOULD BE THE LIKELY CULPRITS. OTHERWISE...DID LOWER TEMPERATURES ON FRIDAY A FEW DEGREES...AS FASTER GFS AND NAM WOULD PRODUCE MORE CLOUD COVER AND LESS HEATING. THIS WOULD PLACE MID 80S ALONG THE NORTHERN ZONES...WITH UPPER 80S FURTHER SOUTH. DUX EXTENDED DISCUSSION (SATURDAY THROUGH WEDNESDAY)... THE COLD FRONT WILL LIKELY BE EXITING THE FORECAST AREA DURING THE EARLY MORNING HOURS ON SATURDAY WITH DRIER AIR FILTERING SOUTHWARD BEHIND THIS BOUNDARY. WITH THIS IN MIND...HAVE CONFINED SLIGHT POPS SOUTH OF THE INTERSTATE 70 CORRIDOR DURING THE MORNING HOURS. THE REMAINDER OF THE EXTENDED PERIOD LOOKS TO BE DRY AS HIGH PRESSURE BUILDS INTO THE REGION WITH THE FRONT STALLING WELL SOUTH OF THE FORECAST AREA ACROSS OKLAHOMA. WITH PERSISTENT LOW-LEVEL FLOW FROM THE NORTHEAST/EAST...HUMIDITY LEVELS SHOULD BE QUITE COMFORTABLE FOR LATE JULY AS DEWPOINTS WILL LIKELY DIP INTO THE LOWER AND MIDDLE 60S. IN ADDITION...THE GFS PROGS PW VALUES ONLY AROUND 0.75 INCHES FOR THE MAJORITY OF THE PERIOD AFTER THE FRONTAL PASSAGE. AS FOR TEMPERATURES...UNDERCUT GUIDANCE A BIT THROUGH THE PERIOD AS THE AFOREMENTIONED SURFACE PATTERN WILL LIKELY YIELD HIGHS IN THE MIDDLE TO UPPER 80S THROUGH THE WEEKEND...WITH READINGS WARMING A FEW DEGREES MORE FOR THE FIRST HALF OF THE UPCOMING WEEK. SAW && .AVIATION... FOR THE 18Z TAFS...DIURNAL CU FIELD FINALLY BEGINNING TO FORM OVER THE TERMINAL SITES. WEAK DISTURBANCE MOVING SOUTH OUT OF NEBRASKA WILL CONTINUE TO PUSH INTO CENTRAL KANSAS THIS EVENING...STAYING WEST OF THE AREA. AS A RESULT...DRY VFR CONDITIONS WILL PREVAIL THROUGH THE TAF CYCLE. DID ADD IN A MENTION OF HAZE IN BOTH MKC AND STJ TERMINALS. LOW-LVL FLOW SHOULD BE SIMILAR TO THAT OF LAST NIGHT...WITH REDUCED VISIBILITIES ONCE AGAIN FORMING TOWARDS DAYBREAK. WILL ALSO NEED TO WATCH FOR FOG GENERATION ESPECIALLY AT STJ...AS CROSSOVER TEMPERATURES WILL BE APPROACHED. DUX && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
322 PM CDT WED JUL 25 2007 .SYNOPSIS... LOW DEVELOPING ALONG THE FRONT RANGE. WAVE SEEN IN WATER VAPOR OVER EASTERN MT ASSOCIAATED COOL FRONT WITH CONVECTION FROM COLORADO FRONT RANGE INTO NORTHWEST SD. MCV DROPPING SOUTHACROSS KS AS SEEN IN WV. && .DISCUSSION... NEAR TERM MODELS HAVING SOME DIFFICULTY WITH TIMING OF FRONTAL PASSAGE. NAM CONTINUOUS WHILE GFS WANTS TO SLOW THINGS DOWN. HAVE USED A BLEND BUT TRENDED TOWARDS NAM. HAVE MOVED PRECIPITATION INTO WESTERN PORTIONS OF THE FORECAST AREA EARLIER THIS EVENING AND PROJECTED PRECIPITATION FURTHER EAST OVERNIGHT. MAIN PUNCH TO COME THURSDAY MORNING WITH UPPER SUPPORT DRIVING INTO SYSTEM. ABUNDANT MOISTURE PW` 1.10 TO 1.5 INCHES. SB CAPE FIGURES IN THE 1500 TO 300 J/KG THURSDAY. HAVE READJUSTED POPS WITH TIMING AND BEST LIFT. THINGS TO START NORTHWEST IN THE AM AND FRONT TO PUSH SOUTHEAST THROUGH THE EVENING. BEST PRECIP ALONG IMPERIAL TO BROKEN BOW LINE IN THE AFTERNOON. SLOW STORM MOTION AND AABUNDANT MOISTURE COULD BE CONCERN FOR RUNOFF. FROPA SHOULD BE FAST ENOUGH TO ALLEVIATE CONCERNS. HAVE BASICALLY MODIFIED HPC QPF AMOUNTS. TEMPERATURES WILL BE TRICKY WITH TIMING OF FRONT AND CLOUD COVER. COOLER NORTH AND SIMILAR TEMPERATURES SOUTH THE SAME AS TODAYS. FRONTAL BOUNDARY TO STALL OUT ALONG FRONT RANGE INTO WESTERN KANSAS. POSITION OF BOUNDARY COULD BE FOCUS FOR THUNDERSTORM DEVELOPMENT OVER SOUTHWEST ZONES THROUGH FRIDAY EVENING. HAVE GONE TOWARDS HIGHER GUIDANCE NUMBERS FOR TEMPS ON FRIDAY IN THE 80`S. RETURNED PRECIP TO EASTERN NE PANHANDLE AND SOUTHWEST ZONES SATURDAY AFT AND EVE WITH UPSLOPE FLOW. TD`S DRY OUT SOME BUT NOT AS MUCH AS YESTERDAYS RUN MID 50S TO LOW 60S. TEMPERATURES TO RISE TO AROUND 90 THROUGH THE WEEKEND AND DRY. NEXT FRONT TO APPROACH FROM THE NORTHWEST ON TUESDAY . HAVE BUMPED POPS UP SLIGHTLY BUT STILL DRY FOR NOW. && .AVIATION... VFR CONDITIONS CAN BE EXPECTED THROUGH SUNRISE AS A FRONT BEGINS TO PUSH ACROSS NEBRASKA. ISOLATED CONVECTION CAN BE EXPECTED ALONG THE FRONT RANGE INTO THE BLACK HILLS AND PINE RIDGE REGION WHERE WIND GUSTS AND HAIL WILL BE HAZARDS TO LIGHT AIRCRAFT. AS THE FRONT PROGRESSES THROUGH THE SANDHILLS AND INTO SOUTHERN NEBRASKA THURSDAY AFTERNOON...CONVECTION WILL BECOME MORE WIDESPREAD...ALONG WITH LOWERING CEILING HEIGHTS ACROSS MUCH OF THE 098 TWEB ROUTE WHERE MVFR CONDITIONS MAY BE MET. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ POWER/13
AREA FORECAST DISCUSSION
NWS SEATTLE WA
310 AM PDT WED JUL 25 2007 .SYNOPSIS...SOME PRETTY TYPICAL SUMMER WEATHER IN STORE FOR WESTERN WASHINGTON THE NEXT FEW DAYS WITH WEAK LOW LEVEL ONSHORE FLOW AT THE SURFACE AND LIGHT SOUTHWESTERLY FLOW ALOFT. A TROUGH OF LOW PRESSURE WILL TAKE UP RESIDENCE OFFSHORE FOR THE WEEKEND. A WEAK SYSTEM MOVING OUT OF THE TROUGH WILL INCREASE THE CLOUD COVER OVER THE AREA FOR THE WEEKEND WITH A CHANCE OF RAIN ALONG THE COAST SATURDAY. && .SHORT TERM...SATELLITE IMAGERY SHOWS STRATUS ALONG THE COAST AND THE NORTHERN CASCADE FOOTHILLS THIS MORNING. GRADIENTS ACROSS THE CASCADES STILL PLUS 5 MB. THE REMAINDER OF THE GRADIENTS ARE FLAT. ACARS SOUNDINGS SHOW NORTH TO NORTHEASTERLY WINDS RIGHT OFF THE GROUND UP TO 850 MB. THIS DOES NOT BODE WELL FOR MUCH ADDITIONAL STRATUS FORMATION THIS MORNING. NOT MUCH CHANGE IN THE SURFACE OR UPPER AIR PATTERN THE NEXT COUPLE OF DAYS WITH LIGHT ONSHORE FLOW AT THE SURFACE AND LIGHT SOUTHWESTERLY FLOW ALOFT WITH AN UPPER LEVEL RIDGE BUILDING OVER THE NORTHERN ROCKIES. STRATUS WILL FORM DURING THE EARLY MORNING HOURS ALONG THE COAST BUT WITH THE LIGHT SURFACE GRADIENTS THE STRATUS WILL HAVE A TOUGH TIME GETTING VERY FAR INLAND. THE LIGHT ONSHORE GRADIENTS WILL KEEP MAX TEMPERATURES WITHIN A COUPLE DEGREES OF NORMAL. SOME SMALL CHANGES START TO TAKE PLACE ON FRIDAY AS A VERTICALLY STACKED LOW MOVES SOUTHEAST TO WEST OF THE QUEEN CHARLOTTES. A FRONT ASSOCIATED WITH THE LOW WILL APPROACH 130W LATE IN THE DAY. .LONG TERM...SAME STORY IN THE EXTENDED WITH THE GFS AND EURO MODELS DRAGGING THE FRONT ASSOCIATED WITH THE LOW INTO WESTERN WASHINGTON LATER SATURDAY INTO SUNDAY. WHILE THE GFS AND EURO ARE IN GOOD AGREEMENT THE CANADIAN MODEL REMAINS MUCH DRIER WITH THE FRONT DISSIPATING ALONG THE COAST. EVEN WITH THE EURO AND GFS PRODUCING PRECIPITATION INLAND 500 MB HEIGHTS REMAIN IN THE MID 570`S DM. HISTORICAL RECORDS SHOW MEASURABLE PRECIPITATION IN SEATTLE ONLY 10 TIMES IN 114 YEARS FOR JULY 29TH. WHILE THIS DID NOT WORK OUT TOO WELL LAST WEEKEND...JULY 21ST AND 22ND ALSO HAD ONLY 10 DAYS OF MEASURABLE PRECIP...THIS SYSTEM BEARS LITTLE RESEMBLANCE TO LAST WEEKENDS SOAKER. THE PW VALUES ARE LOWER AND MORE IMPORTANTLY THE JET ASSOCIATED WITH THIS SYSTEM IS A MORE SUMMERLIKE 70 KTS NOT 100 TO 120 KNOTS THAT WE SAW LAST WEEKEND. WILL STAY WITH THE CURRENT IDEA OF INCREASING THE CLOUD COVER FOR THE WEEKEND BUT REFRAIN FROM PUTTING PRECIPITATION IN THE FORECAST FOR THE INTERIOR. THE SOUTHWESTERLY FLOW ALOFT WITH LIGHT ONSHORE SURFACE GRADIENT PATTERN RETURNS FOR THE FIRST PART OF THE WORKWEEK NEXT WEEK. FELTON && .AVIATION...SKIES ARE MOSTLY CLEAR WITH THE EXCEPTION OF SOME STRATUS ALONG THE COAST...AND DON`T EXPECT MUCH CHANGE THIS MORNING. THE COASTAL STRATUS WILL BURN OFF AFTER 16-18Z FOR MOSTLY CLEAR SKIES ACROSS THE REGION. WINDS SHOULD BE SIMILAR TO TUESDAY EXCEPT A COUPLE OF KNOTS LOWER IN SPEED. KSEA...CLEAR SKIES. LIGHT NE WINDS WILL BE NORTH TO NORTHWEST LATE THIS MORNING INTO THIS EVENING AT ROUGHLY 06-10KT. CERNIGLIA && .SEW WATCHES/WARNINGS/ADVISORIES... .SMALL CRAFT ADVISORY CENTRAL STRAIT...EAST ENTRANCE. $$ WEATHER.GOV/SEATTLE
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
259 AM PDT FRI JUL 27 2007 .SHORT TERM (TODAY-SUNDAY)...EDDY CIRCULATION IS ATTEMPTING TO DEVELOP EARLY THIS MORNING. BENEATH THE HIGH LEVEL MOISTURE FROM LAST EVENINGS CONVECTION...LOWER LEVEL STRATUS CLOUDS CAN BE SEEN DEVELOPING ON FOG PRODUCT IMAGERY ALONG THE ORANGE AND SAN DIEGO COUNTY COASTLINES. MARINE INTRUSION SHOULD MAKE THE SOUTHERN MOST LOS ANGELES COUNTY BEACHES BY DAYBREAK...BUT INTRUSION INTO THE VENTURA COUNTY COASTS AND THE MALIBU AREA MAY BE INHIBITED AT THIS TIME. A FAIRLY DECENT SURGE OF MOISTURE IS OCCURRING THIS MORNING OVER RIVERSIDE AND IMPERIAL COUNTIES. CONCERN IS THAT THIS SURGE MAY BECOME MORE WIDESPREAD. GFS 600 MB RELATIVE HUMIDITY DATA PINPOINTED THE AREAS OF CONVECTION QUITE NICELY YESTERDAY. IF GFS 600 MB RELATIVE HUMIDITY PATTERN IS CORRECT TODAY...SAN GABRIEL MOUNTAINS SHOULD SEE CONVECTIVE STORMS FIRE OVER THE TERRAIN. IT IS POSSIBLE THAT SOME OF THE CONVECTION COULD SPREAD A LITTLE FURTHER NORTH AND WEST INTO THE VENTURA COUNTY MOUNTAINS. 850 MB AND 700 MB MIXING RATIO DATA CERTAIN INDICATE THAT ENOUGH MOISTURE IS PRESENT TO FORM CONVECTION...WITH SLIGHT HIGHER MIXING RATIOS FORECASTED RELATIVE TO YESTERDAY. POPS HAVE BEEN INCREASED ALSO FOR SATURDAY...AND IF MODELS ARE CORRECT THIS COULD BE ONE OF THE BETTER DAYS FOR CONVECTION TO FIRE OVER THE MOUNTAINS AS SOUTHWEST FLOW IS WEAKEST AND MOISTURE AT LOWER AND MIDDLE LEVELS STARTS TO INCREASE. MODELS STRUGGLING A BIT TO PIN DOWN WHAT MAY HAPPEN FOR THE REMAINDER OF THE WEEKEND. WITH TROPICAL STORM DALILA TO THE SOUTH...THERE IS A HUNCH THAT THE AREA SHOULD SEE MOISTURE SLOWLY INCREASING THROUGHOUT THE WEEKEND. BOTH MODELS ARE HINTING AT SOME PORTION THE REMAINS OF THE TROPICAL SYSTEM PUSH NORTH THROUGH THE COASTAL WATERS. GFS IS INDICATING THAT THE CIRCULATION CENTER PUSH OVER THE AREA SUNDAY. MAIN CONCERN IS THAT FLOW ALOFT MAY BE TOO STRONG SOUTHWESTERLY AND DRY OUT THE AIRMASS. CONVECTION IF ANY SHOULD REMAIN LIMITED TO THE MOUNTAINS AND DESERTS ON SUNDAY. .LONG TERM (MONDAY-THURSDAY)...MODELS ARE STILL STRUGGLING ON MODELING THE REMAINS OF TROPICAL STORM DALILA. THE UPPER-LEVEL CIRCULATION EXITS THE AREA BY MONDAY...BUT THE MODELS STRUGGLE WITH THE LOWER-LEVEL PLUME. RUN-TO-RUN CONSISTENCY IS QUITE LOW...SO VERY LITTLE CONFIDENCE SHOULD BE PLACED WITH ANY POPS FOR MIDWEEK. NAM SEEMS TO BE VERY AGGRESSIVE WITH MOISTURE...BUT BASED ON THE FORECASTED UPPER-LEVEL HIGH CENTER...AREA SHOULD BE DRIER AND MORE STABLE. GFS AND ECMWF ARE BOTH INDICATING ANOTHER POSSIBLE SURGE OF MOISTURE FOR LATE NEXT WEEK. POPS HAVE BEEN EXTENDED TO ACCOUNT FOR THIS...BUT WITH MODEL PERFORMANCE LACKING IN THE MEDIUM RANGE...LITTLE CONFIDENCE EXISTS AT THIS TIME. && .AVIATION...27/0930Z...LATEST ACARS AND PROFILER DATA NEAR KLAX INDICATED RELATIVELY STRONG INVERSION NEAR 800 FT. CHANCES ARE THAT SOME LOW CLOUDS AND FOG...SOME DENSE COULD DEVELOP FROM NEAR ORANGE COUNTY AND MOVE NORTHWARD TOWARD LA COUNTY IMMEDIATE COASTAL AREAS BY SUNRISE. NOT TOO CONFIDENT HOWEVER THAT THIS WILL OCCUR. AREAS S OF POINT CONCEPTION SHOULD REMAIN IN VFR CATEGORY TODAY....WITH SOME LOCAL HAZE NEAR SUNRISE FOR A FEW HOURS. N OF POINT CONCEPTION...LOW CLOUDS IN LIFR CIGS CAT AND SHOULD LOWER TO IFR TO LIFR VSBYS BY EARLY MORNING HOURS AT KSMX AND KSBP THIS MORNING WITH BURNOFF NEAR 17Z TODAY. KPRB COULD ALSO SEE LIFR/IFR CIGS BEFORE DAWN...BUT ONLY MODERATE CONFIDENCE FOR THIS TO OCCUR. KLAX...EXPECT MOSTLY SUNNY SKIES WITH LOW CONFIDENCE OF STRATUS NEAR THE IMMEDIATE COAST OF KLAX BY SUNRISE. IF STRATUS DOES OCCUR...IT SHOULD REMAIN IFR CIGS AND VSBYS THROUGH 9 AM. TYPICAL SEABREEZE PATTERN TODAY WITH WINDS GENERALLY BELOW 12 KT. KBUR...VFR CONDITIONS WILL PREVAIL...WITH SOME LOCAL HAZE NEAR SUNRISE. TYPICAL DIURNAL WIND PATTERN. && .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXCWFLOX). && $$ PUBLIC...HALL AVIATION...KAPLAN WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
400 AM EDT FRI JUL 27 2007 .SYNOPSIS... THE PERSISTENT UPPER LOW NEAR THE GREAT LAKES WILL WEAKEN AND MOVE EASTWARD AS AN OPEN TROUGH OVER THE NEXT FEW DAYS. THIS PATTERN WILL KEEP US IN A VERY WARM AND HUMID AIRMASS THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO REACH OUR AREA SUNDAY NIGHT OR MONDAY AND THEN MOVE SLOWLY OFF TO THE EAST TUESDAY. HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY NIGHT INTO WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... EXPECT PRECIP CHANCES TO INCREASE SOMEWHAT LATER TODAY AND TONIGHT AS UPPER LOW STARTS MOVING...FINALLY. SOME DECENT OMEGA MAY APPROACH OUR NRN AND WRN COUNTIES BY TONIGHT BUT THERE IS STILL NOT A LOT OF SUPPORT FOR MORE THAN DIURNAL SHOWERS AND STORMS. HOWEVER, WITH THE WARM AND HUMID AIRMASS IN PLACE, AREAL COVERAGE MAY BE A BIT MORE WIDESPREAD THAN THE LAST FEW DAYS. MOS GUIDANCE VARIES QUITE A BIT WITH THE GFS ABOUT 8-10 DEGREES HIGHER THAN THE NAM. WILL SPLIT THE DIFFERENCE DUE TO THE GFS OVER-FORECASTING ITS HIGHS OF LATE. OF COURSE, TEMPS WILL BE HIGHLY DEPENDENT ON CLOUD COVER AS WELL AS ANY PRECIP WHICH DOES OR DOES NOT FALL. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... THE UPPER LOW WILL BE ON THE MOVE EASTWARD AND THE ASSOCD SFC CDFNT WILL APPROACH THE REGION. THE COLD FRONT APPEARS TO GET WASHED OUT BY SUNDAY AS IT LINGERS OVER THE REGION. THE GFS IS MUCH MORE ROBUST THAN THE WRF WITH THE DEVELOPMENT OF A SFC LOW IN THE SRN MID-ATLC STATES. THE CANADIAN HAS A WEAKER LOW FURTHER S. SATURDAY AND SUNDAY COULD END UP BEING QUITE WET WITH THE PROXIMITY OF THE FRONT AND UPPER LOW AND A WARM HUMID AIRMASS IN PLACE. IT LOOKS AS IF THIS WILL BE THE PERIOD WITH THE BEST CHANCES OF A MORE WIDESPREAD RAIN RATHER THAN JUST DIURNAL SHOWERS/STORMS. WILL HOLD OFF ON SIGNIFICANTLY INCREASING POPS OVER THE WEEKEND UNTIL PERHAPS WE HAVE A BETTER HANDLE ON WHICH PERIODS LOOK WETTEST. WILL MAKE SOME UPWARD TWEAKS ATTM THOUGH. THE BEST OMEGA IS GENERALLY IN THE NRN AND WRN ZONES AND THERE ARE MULTIPLE S/WVS THAT COULD OR COULD NOT MOVE THROUGH DURING THIS TIME. MODELS DIFFER GREATLY ON HIGH TEMPERATURES WITH THE GFS MUCH WARMER THAN THE NAM. WE WILL GO MIDDLE OF THE ROAD SINCE THE GFS HAS BEEN OVER FORECASTING HIGHS RECENTLY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THERE IS SOMEWHAT BETTER AGREEMENT IN THE EXTENDED FCST TONIGHT THEN THERE WAS LAST NIGHT, BUT STILL SOME UNCERTAINTY. SO WILL NOT BE MAKING MANY MAJOR CHANGES TO THE EXTENDED. THE COLD FRONT WHICH WILL APPROACH THE REGION WILL BECOME WASHED OUT AND MOVE VERY SLOWLY OVER THE REGION. SEVERAL WAVES OF LOW PRESSURE MAY MOVE ACROSS THE DIFFUSE BOUNDARY SUNDAY NIGHT THROUGH EARLY TUESDAY. UNLIKE LAST NIGHT, WHEN THE GFS WAS ALONE IN DEVELOPING A SFC LOW ACROSS THE MID-ATLC FROM SUNDAY NIGHT INTO TUESDAY, THE GFS DOES HAVE SOME SUPPORT TODAY FROM THE CANADIAN. THIS LOW WOULD KEEP PRECIP CHANCES INTO EARLY NEXT WEEK, BEFORE IT FINALLY MOVES ON. HOWEVER, THE UKMET DIFFERS SIGNIFICANTLY WITH A MUCH WEAKER LOW FURTHER S. THE ECMWF HAS A BARELY IDENTIFIABLE SFC LOW. SO EVEN THOUGH THE CANADIAN IS IN THE GFS CAMP, WITH THE OTHER MODELS DIFFERING SIGNIFICANTLY, THIS IS STILL A LOW CONFIDENCE FCST. IT LOOKS LIKE THERE WILL BE SOME DECENT PRECIP CHANCES SUNDAY NIGHT AND MONDAY WITH THE UPPER LOW MOVING OVER THE REGION AND SEVERAL S/WVS AS WELL. ONCE WE GET INTO THE FRONTAL ZONE, SHOWER AND TSTM ACTIVITY WILL INCREASE, ESPECIALLY IF A WAVE FORM ON THE FRONT. THE TIME PERIOD HIGH PRESSURE IS THEN EXPECTED TO BUILD IN AROUND MIDWEEK, ACCORDING TO EVEN THE SLOWEST AND MOST PESSIMISTIC MODELS. TEMPERATURES ARE EXPECTED TO REMAIN NEAR SEASONAL VALUES THROUGH THE PERIOD. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AT 0730Z, PATCHES OF STRATUS WERE FLOATING OVER OUR REGION. THE INITIAL DEVELOPMENT OF A LARGE AREA OF STRATUS OVER OUR TAF SITES ALONG THE DELAWARE RIVER AROUND 04Z AND 05Z WAS A BIT PUZZLING. A COUPLE OF ACARS SOUNDINGS FROM AROUND THAT TIME WEREN`T SHOWING MUCH OF A LOW LEVEL TEMP INVERSION. THAT CONTINUED TO BE THAT CASE AROUND 07Z WITH ANOTHER ACARS SOUNDING. A WEAK MID LEVEL SHORT WAVE WAS ROTATING UP FROM THE SOUTHWEST IN THE CIRCULATION AROUND THE LOW THAT WAS LOCATED OVER EASTERN MICHIGAN DURING THE NIGHT. IT NOW APPEARS AS THOUGH THE APPROACHING SHORT WAVE WAS STRONG ENOUGH TO MIX THE ATMOSPHERE A BIT, BRINGING AN END TO THE DEVELOPMENT OF ANY WIDESPREAD STRATUS. AGAIN, WITH THERE NOT BEING MUCH OF A LOW LEVEL TEMP INVERSION, WE`VE BACKED OFF A BIT ON THE LOW CONDITIONS FOR EARLY THIS MORNING THAT WERE ORIGINALLY FORECAST IN THE 06Z TAFS. AMENDMENTS WERE ISSUED AROUND 0720Z. IT APPEARS AS THOUGH THERE WILL BE A BETTER CHANCE FOR PRECIP TODAY THAN ON THURSDAY. WITH THE TIMING OF ANY PRECIP BEING UNCERTAIN, WE`VE CARRIED CUMULONIMBUS IN MOST OF OUR TAFS FROM 19Z ONWARD. THE ONLY EXCEPTIONS ARE KMIV AND KACY WHERE WE DID NOT CARRY CUMULONIMBUS BEING THAT IT APPEARS AS THOUGH THOSE LOCATIONS WILL HAVE A SLIGHTLY LOWER CHANCE FOR PRECIP. THEY ARE A LITTLE MORE REMOVED FROM THE INFLUENCE OF THE MID LEVEL LOW AND ANY TERRAIN EFFECTS. THE SOUTH SOUTHEAST FLOW OFF THE OCEAN SHOULD ACTUALLY HELP KEEP KMIV AND KACY UNDER SOMEWHAT MORE STABLE CONDITIONS FOR THIS AFTERNOON AND EVENING. THERE WILL BE A CONTINUING CHANCE FOR MAINLY AFTERNOON AND EVENING SHOWERS AND TSTMS FROM SATURDAY THROUGH MONDAY AS A SLOW MOVING FRONTAL BOUNDARY FROM THE NORTHWEST DROPS THROUGH OUR REGION. && .MARINE... A BROAD SOUTH TO SOUTHEAST FLOW IS EXPECTED OVER OUR MARINE AREA FOR TODAY AND INTO THE WEEKEND, UNTIL A FRONTAL BOUNDARY SLOWLY DROPS DOWN FROM THE NORTHWEST ON MONDAY. THERE WILL BE AN INCREASING CHANCE FOR SHOWERS AND TSTMS AS WE GO THROUGH THE WEEKEND. WIND SPEEDS ARE EXPECTED TO REMAIN MOSTLY BELOW 15 KNOTS INTO THE EARLY PART OF THE NEW WEEK. WAVES ON THE OCEAN WATERS OFF NEW JERSEY AND DELAWARE SHOULD REMAIN MOSTLY BETWEEN 2 AND 4 FEET. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...NIERENBERG NEAR TERM...NIERENBERG SHORT TERM...NIERENBERG LONG TERM...NIERENBERG AVIATION...IOVINO MARINE...IOVINO
AREA FORECAST DISCUSSION
NWS SEATTLE WA
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`S DM...SO EVEN THOUGH MODELS SQUEEZE OUT A FEW HUNDREDTHS CHANCE POPS LOOK GOOD. .LONG TERM...LONG TERM PROGS REMAINING CONSISTENT FOR THE FIRST HALF OF NEXT WEEK WITH WESTERN WASHINGTON IN LIGHT ONSHORE GRADIENTS WITH A FLAT RIDGE ALOFT. VARYING DEGREES OF ONSHORE FLOW EACH DAY BUT THE GENERAL IDEA OF MOSTLY SUNNY CONDITIONS AND TEMPS NEAR NORMAL LOOKS GOOD. ANOTHER LOW DEVELOPS A LITTLE FURTHER SOUTH THAN THE ONE FOR SUNDAY ON THURSDAY NEXT WEEK ACCORDING TO THE MODELS. THIS IS A SOMEWHAT NEW FEATURE IN THE MODELS. SINCE IT IS DAY SEVEN WILL STAY WITH PERSISTENCE FOR NOW. FELTON .AVIATION...STRATUS FORMING PRETTY MUCH AS PLANNED...EXCEPT BASES ARE A FEW HUNDRED FEET HIGHER THAN I WOULD HAVE THOUGHT...A GOOD THING FOR PLANES. IT SHOULD CONTINUE TO SLOWLY FILL IN EARLY THIS MORNING THEN SLOWLY BREAK UP FOR A MOSTLY SUNNY AFTERNOON. KSEA...WINDS WILL REMAIN LIGHT S-SW THROUGH MUCH OF THE DAY...THEN BECOMING WSW THIS AFTERNOON. IT SHOULD NOT DEVELOP A NORTHERLY COMPONENT TODAY. BKN-SCT CLOUDS WITH BASES GENERALLY 2500-3000 FT THIS MORNING...SLOWLY LIFTING AND BREAKING UP LATE THIS MORNING. JUST A FEW SCT CLOUDS THIS AFTERNOON. CERNIGLIA && .SEW WATCHES/WARNINGS/ADVISORIES... .SMALL CRAFT ADVISORY CENTRAL STRAIT AND EAST ENTRANCE AND ADMIRALTY INLET. $$ WEATHER.GOV/SEATTLE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1120 AM EDT FRI JUL 27 2007 .MORNING UPDATE... DOING A QUICK UPDATE TODAY TO LOWER MAX TEMPS ACROSS THE EAST A COUPLE OF DEGREES BASED ON MORNING SHOWERS/STORMS. STRONG SHORTWAVE AND MCV CAN BE SEEN NEAR MILWAUKEE/CHICAGO FROM WATER VAPOR AND VIS SAT RESPECTIVELY. DRY AIR ALOFT AND FASTER 500MB WINDS FROM THE DISTURBANCE WILL HELP DESTABILIZE THE ATMOSPHERE AS WELL AS INCREASE DEEP-LAYER SHEAR. THESE SHOULD COMBINE TO CREATE A MARGINALLY-SEVERE ATMOSPHERE TODAY. OUR NERN HALF OF THE CWA MAY BE A BIT WORKED-OVER FROM THE MORNING PRECIP BASED ON CURRENT SDF ACARS SOUNDING...BUT THERE ARE BREAKS IN THE CLOUDS SO INSTABILITY SHOULD INCREASE INTO THE EARLY AFTERNOON HOURS. AND ACTUALLY A FEW SMALL CELLS ARE ALREADY DEVELOPING OVER CENTRAL-SOUTHERN INDIANA AND SOUTHERN OHIO. FORECAST SOUNDINGS HOWEVER ARE NOT THAT IMPRESSIVE...BUT SHOULD BE ENOUGH TO YIELD MARGINALLY SEVERE HAIL/WINDS THIS AFTERNOON AND EVENING. THE DAY ONE OUTLOOK FROM SPC LOOKS PRETTY GOOD...THOUGH I THINK EVEN SRN KY COULD SEE SOME SEVERE BECAUSE OF THE HIGHER INSTABILITY IN THAT REGION. OTHERWISE...THE FORECAST IS IN GOOD SHAPE. HAVE LIKELY POPS ACROSS SRN IN DOWN TO 40 POPS ACROSS SRN KY. UPDATE OUT SHORTLY. AL && .PREV DISCUSSION... SHORT TERM (TODAY AND TONIGHT)... THUNDERSTORM POTENTIAL THIS MORNING AND AGAIN LATER THIS AFTERNOON AND TONIGHT IS THE MAIN WEATHER PROBLEM FOR THE SHORT TERM PERIOD. FIRST WE HAVE TO DEAL WITH SCATTERED TRW/RW THAT DEVELOPED DURING THE PAST TWO OR THREE HOURS TO OUR WEST AND NORTHWEST THAT WILL LIKELY MOVE TO THE ESE ACROSS PORTIONS OF NORTH CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA THIS MORNING. MODELS DO SHOW SOME INCREASING LOW LEVEL CONVERGENCE ACROSS THIS AREA INTO THE MORNING HOURS AS THE LOW LEVEL FLOW INCREASES TO OUR WEST IN ADVANCE OF AN APPROACHING SHORT WAVE OFF TO OUR NORTHWEST. LATER TODAY INTO TONIGHT THE SHORT SHORT WAVE SWEEPS BY TO OUR NORTHEAST AND COMBINED WITH ITS ASSOCIATED FRONTAL SYSTEM... IN COMBINATION WITH DAYTIME HEATING...AND RATHER HIGH SFC DEWPOINTS NEAR 70...SHOULD TRIGGER MORE NUMEROUS SHOWERS AND THUNDERSTORMS. SOME OF THE STORMS COULD BE STRONG OR LOCALLY SEVERE...ESPECIALLY ACROSS SOUTH CENTRAL INDIANA AND PORTIONS OF NORTH CENTRAL AND EAST CENTRAL KENTUCKY. HPC QPF TRENDS EXCEPT FOR THIS MORNING LOOKED OK AND WILL BE USED FOR THE SHORT TERM. AS FOR TEMP TRENDS MORE LESS PERSISTENCE WITH THE CURRENT TRENDS AND THAT AGREES WITH THE PREFERRED NEW MAV FCSTS. --21 LONG TERM (SATURDAY THROUGH THURSDAY)... SATURDAY THROUGH SUNDAY NIGHT... MAIN FORECAST PROBLEM DURING THIS PD WILL BE RAIN CHANCES ON SATURDAY AS FRONTAL BOUNDARY CONTINUES TO PUSH THROUGH THE REGION. LATEST MODEL SOLUTIONS CONTINUE TO BE IN GOOD AGREEMENT WITH FRONTAL BOUNDARY WORKING THROUGH THE STATE ON SATURDAY. RESIDUAL CONVECTION WILL BE LIKELY ONGOING AT THE BEGINNING OF THE PD ACROSS MUCH OF THE AREA...BUT MAIN CONCENTRATION OF ACTIVITY WILL ACROSS OUR EASTERN AND SOUTHERN SECTIONS. THUS...WILL MAINTAIN MOSTLY CLOUDY SKIES WITH CHC POPS THROUGH THE DAY. MODEL TIME-HEIGHT PLOTS SHOW DECENT DRYING COMING IN SAT NIGHT WHICH SHOULD END PRECIP ACROSS THE REGION. TEMPERATURES WILL REMAIN WARM ON SAT WITH READINGS OF 82 TO 87 AND LOWS IN THE MID 60S BY SUN MORNING. UPPER LEVEL AND SFC RIDGE ARE FORECAST TO BUILD INTO THE REGION ON SUNDAY BRINGING DRY WEATHER TO MUCH OF THE FA. HIGHS WILL A COUPLE OF DEGREES WARMER ON SUNDAY WITH HIGHS OF 83 TO 88. MONDAY THROUGH THURSDAY... CURRENT FCST THROUGH THIS TIME PERIOD IS IN GOOD SHAPE AT THIS TIME. LATEST MODEL CONSENSUS CONTINUES TO TREND CLOSE TO PREVIOUS MODEL RUNS FROM THU MORNING/AFTERNOON. BELT OF WESTERLIES WILL REMAIN WELL NORTH OF THE REGION WITH A BAGGY H5 TROF REMAINING ENTRENCHED ACROSS THE U.S. EAST COAST. UPSTREAM H5 RIDGE IS FCST TO EXPAND SLOWLY AND CREEP EASTWARD INTO THE WESTERN OHIO VALLEY DURING THE PD. SENSIBLE WEATHER WOULD BE DRY WITH MODERATING TEMPERATURES THROUGH THE PD. CURRENT FCST HANDLES THIS QUITE WELL AND ONLY MADE SOME MINOR ADJUSTMENTS IN THE MON/TUE TIME FRAME. -MJ AVIATION (12Z TAFS)... MAIN CONCERN FOR TAFS IS THE TSTM POTENTIAL THIS MORNING AND THE MORE WIDESPREAD POTENTIAL MIDDAY INTO TONIGHT. LATEST NAM12 AND RUC40 INDICATE THAT MAIN PVA WI SYS TO ROTATE INTO NRN FA BY MIDDAY. WILL GO WI TEMPO TRW GROUP FOR 17-18Z LEX-SDF AND AROUND 21Z FOR BWG. WI COLD FRONT LAGGING BEHIND THE BEST SYNOPTIC SCALE LIFT...WILL KEEP VCTS IN TAFS INTO TONIGHT WITH GENERALLY VFR CONDS UNTIL LATE AND THEN WILL GO MVFR VSBY CONDS AS SFC GRADIENT RELAXES WITH NOT MUCH DRYING TAKING PLACE UNTIL SAT. --21 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PDT FRI JUL 27 2007 .SYNOPSIS... MOISTURE IN EASTERLY FLOW ALOFT WILL CONTINUE A CHANCE OF SHOWERS OR THUNDERSTORMS IN THE MOUNTAINS AND DESERTS...MAINLY DURING THE AFTERNOONS AND EVENINGS. A SHALLOW MARINE LAYER WILL CAUSE AREAS OF COASTAL LOW CLOUDS AND FOG IN THE NIGHTS AND MORNINGS. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES. .SHORT TERM (TODAY-MON)... THERE WERE PATCHES OF LOW CLOUDS AND FOG IN THE COASTAL AREAS THIS MORNING AND STRATUS REMAINS QUITE EXTENSIVE OFFSHORE. THERE WERE ALSO MID LEVEL DEBRIS CLOUDS. THE 12Z NKX SOUNDING HAD AN INVERSION BASED BELOW 1000 FT. PRECIPITABLE WATER WAS 1.44 INCHES AND THE SOUNDING SHOWED MODERATE INSTABILITY. SLIGHTLY STRONGER ONSHORE GRADIENTS WITH 3-4 MB SAN-IPL. EARLY AFTERNOON ACARS SOUNDINGS INDICATE THE INVERSION WAS STILL BASED BELOW 1000 FT. THUNDERSTORMS WERE BEGINNING TO DEVELOP OVER THE MOUNTAINS THIS AFTERNOON. UPPER LEVEL HIGH PRESSURE WILL CONTINUE OVER THE SW WITH A SERIES OF WEAK SHORT WAVE TROUGHS MOVING THROUGH THE PAC NW THROUGH THE SHORT TERM. THERE WILL BE ENOUGH MOISTURE AND INSTABILITY FOR ISOLATED THUNDERSTORMS IN THE MOUNTAINS AND DESERTS. THE MOISTURE BECOMES A LITTLE MORE ELEVATED BUT CONTINUES THROUGH EARLY NEXT WEEK WHICH WILL MAINTAIN A SLIGHTLY LOWER CHANCE OF THUNDERSTORMS IN THE MOUNTAINS AND DESERTS EACH AFTERNOON AND EVENING. THE FLOW ALOFT REMAINS WEAK SO THUNDERSTORMS WILL BE SLOW MOVING AND COULD PRODUCE FLASH FLOODING IN THE MOUNTAINS WITH WATER POSSIBLY FLOWING DOWN THE DESERT SLOPES AND A FLASH FLOOD WATCH IS IN EFFECT INTO THIS EVENING. AN ISOLATED SEVERE THUNDERSTORM CANNOT BE RULED OUT. AN INTERMITTENT COASTAL EDDY SHOULD MAKE THE MARINE LAYER A LITTLE MORE EXTENSIVE. HOWEVER...THE MARINE LAYER WILL REMAIN FAIRLY SHALLOW WITH LOW CLOUDS AND FOG MOSTLY CONFINED TO THE COASTAL AREAS DURING THE LATE NIGHTS AND MORNINGS. THE INCREASED MARINE INFLUENCE WILL BRING A LITTLE COOLING W OF THE MOUNTAINS. && .LONG TERM (TUE-FRI)... EXTENDED PROGS INDICATE NOT MUCH CHANGE IN THE GENERAL PATTERN AT LEAST THROUGH MID WEEK. THERE ARE SOME INDICATIONS OF A DRYING TREND TOWARD THE END OF NEXT WEEK WHICH WOULD RESULT IN A DECREASE IN THUNDERSTORM ACTIVITY. && .AVIATION... 271900Z...MDCRS SOUNDINGS CONTINUE TO SHOW THE MARINE LAYER DEPTH 500 FEET OR LESS ALONG THE COAST. A COASTAL EDDY IS EXPECTED TO DEVELOP THIS EVENING AND OVERNIGHT WHICH WILL HELP DEEPEN THE MARINE LAYER A LITTLE THROUGH SATURDAY TO AROUND 1200 FEET. STRATUS WITH BASES AROUND 500 FEET MSL SHOULD DEVELOP ALONG THE COAST THIS EVENING THEN PUSH LOCALLY INLAND OVERNIGHT. STRATUS SHOULD MOVE OVER KSAN BY 08Z TONIGHT. BASES COULD BE LOW ENOUGH TO BE BELOW LOCALIZER RUNWAY 27 MINIMUMS. STRATUS SHOULD CLEAR BY 16Z ON SATURDAY. ISOLATED THUNDERSTORMS ARE EXPECTED THROUGH SUNSET FOR THE MOUNTAINS AND ADJACENT DESERT AREAS FROM THE MEXICAN BORDER NORTH TO NEAR BIG BEAR LAKE. BASES COULD BE AS LOW AS FL080 WITH TOPS AT OR ABOVE FL400 AT TIMES. HORTON && .SGX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FOR THE MOUNTAINS AND DESERTS UNTIL 7 PM PDT THIS EVENING. SEE LAXFFASGX FOR DETAILS. && $$ PUBLIC...DVA AVIATION...HORTON
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
1130 AM PDT FRI JUL 27 2007 .SYNOPSIS... MOISTURE IN EASTERLY FLOW ALOFT WILL CONTINUE A CHANCE OF SHOWERS OR THUNDERSTORMS IN THE MOUNTAINS AND DESERTS...MAINLY DURING THE AFTERNOONS AND EVENINGS. A SHALLOW MARINE LAYER WILL CAUSE AREAS OF COASTAL LOW CLOUDS AND FOG IN THE NIGHTS AND MORNINGS. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES. .SHORT TERM (TODAY-MON)... THERE WERE PATCHES OF LOW CLOUDS AND FOG IN THE COASTAL AREAS THIS MORNING AND STRATUS REMAINS QUITE EXTENSIVE OFFSHORE. THERE WERE ALSO A FEW MID LEVEL DEBRIS CLOUDS. THE 12Z NKX SOUNDING HAD AN INVERSION BASED BELOW 1000 FT. PRECIPITABLE WATER WAS 1.44 INCHES AND THE SOUNDING SHOWED MODERATE INSTABILITY. WEAK ONSHORE GRADIENTS. UPPER LEVEL HIGH PRESSURE WILL CONTINUE OVER THE SW WITH A SERIES OF WEAK SHORT WAVE TROUGHS MOVING THROUGH THE PAC NW THROUGH THE SHORT TERM. THERE WILL BE ENOUGH MOISTURE AND INSTABILITY FOR ISOLATED THUNDERSTORMS IN THE MOUNTAINS TODAY WITH A LITTLE LOWER CHANCE IN THE DESERTS. THE MOISTURE BECOMES A LITTLE MORE ELEVATED BUT CONTINUES THROUGH EARLY NEXT WEEK WHICH WILL MAINTAIN A SLIGHTLY DECREASED CHANCE OF THUNDERSTORMS IN THE MOUNTAINS AND DESERTS EACH AFTERNOON AND EVENING. THE FLOW ALOFT REMAINS WEAK SO THUNDERSTORMS WILL BE SLOW MOVING AND COULD PRODUCE FLASH FLOODING IN THE MOUNTAINS AND ADJACENT DESERTS...ESPECIALLY TODAY AND A FLASH FLOOD WATCH IS IN EFFECT. AN ISOLATED SEVERE THUNDERSTORM CANNOT BE RULED OUT. AN INTERMITTENT COASTAL EDDY SHOULD MAKE THE MARINE LAYER A LITTLE MORE EXTENSIVE. HOWEVER...THE MARINE LAYER WILL REMAIN FAIRLY SHALLOW WITH LOW CLOUDS AND FOG MOSTLY CONFINED TO THE COASTAL AREAS DURING THE NIGHTS AND MORNINGS. THE INCREASED MARINE INFLUENCE WILL BRING A LITTLE COOLING W OF THE MOUNTAINS. && .LONG TERM (TUE-FRI)... EXTENDED PROGS INDICATE NOT MUCH CHANGE IN THE GENERAL PATTERN AT LEAST THROUGH MID WEEK. THERE ARE SOME INDICATIONS OF A DRYING TREND TOWARD THE END OF NEXT WEEK WHICH WOULD RESULT IN A DECREASE IN THUNDERSTORM ACTIVITY. && .AVIATION... 271400Z...MARINE LAYER DEPTH THIS MORNING WAS LESS THAN 700 FEET BASED ON MDCRS SOUNDINGS. MARINE LAYER DEPTH WILL SHOW LITTLE CHANGE TODAY BUT MAY DEEPEN SLIGHTLY TONIGHT AND SATURDAY IN RESPONSE TO A DEVELOPING COASTAL EDDY. PATCHY STRATUS ALONG THE COAST WITH BASES AROUND 500 FEET MSL FROM CENTRAL SAN DIEGO COUNTY NORTH TO ORANGE COUNTY SHOULD BREAK UP BY 16Z. STRATUS SHOULD REFORM ALONG THE COAST THIS EVENING THEN PUSH LOCALLY INLAND TONIGHT. STRATUS SHOULD MOVE OVER KSAN BETWEEN 06Z AND 08Z TONIGHT. BASES COULD BE LOW ENOUGH TO BE BELOW LOCALIZER RUNWAY 27 MINIMUMS. STRATUS SHOULD CLEAR BY 16Z ON SATURDAY. ISOLATED THUNDERSTORMS ARE EXPECTED LATE THIS MORNING THROUGH SUNSET FOR THE MOUNTAINS AND ADJACENT DESERT AREAS FROM THE MEXICAN BORDER NORTH TO NEAR BIG BEAR LAKE. BASES COULD BE AS LOW AS FL080 WITH TOPS AT OR ABOVE FL400 AT TIMES. HORTON && .SGX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FOR THE MOUNTAINS AND DESERTS UNTIL 7 PM PDT THIS EVENING. SEE LAXFFASGX FOR DETAILS. && $$ PUBLIC...DVA AVIATION...HORTON
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
930 AM PDT FRI JUL 27 2007 .SYNOPSIS... MOISTURE IN EASTERLY FLOW ALOFT WILL CONTINUE A CHANCE OF SHOWERS OR THUNDERSTORMS IN THE MOUNTAINS AND DESERTS...MAINLY DURING THE AFTERNOONS AND EVENINGS. A SHALLOW MARINE LAYER WILL CAUSE AREAS OF COASTAL LOW CLOUDS AND FOG IN THE NIGHTS AND MORNINGS. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES. .SHORT TERM (TODAY-MON)... THERE WERE PATCHES OF LOW CLOUDS AND FOG IN THE COASTAL AREAS THIS MORNING AND STRATUS REMAINS QUITE EXTENSIVE OFFSHORE. THERE WERE ALSO A FEW MID LEVEL DEBRIS CLOUDS. THE 12Z NKX SOUNDING HAD AN INVERSION BASED BELOW 1000 FT. PRECIPITABLE WATER WAS 1.44 INCHES AND THE SOUNDING SHOWED MODERATE INSTABILITY. WEAK ONSHORE GRADIENTS. UPPER LEVEL HIGH PRESSURE WILL CONTINUE OVER THE SW WITH A SERIES OF WEAK SHORT WAVE TROUGHS MOVING THROUGH THE PAC NW THROUGH THE SHORT TERM. THERE WILL BE ENOUGH MOISTURE AND INSTABILITY FOR ISOLATED THUNDERSTORMS IN THE MOUNTAINS TODAY WITH A LITTLE LOWER CHANCE IN THE DESERTS. THE MOISTURE BECOMES A LITTLE MORE ELEVATED BUT CONTINUES THROUGH EARLY NEXT WEEK WHICH WILL MAINTAIN A SLIGHTLY DECREASED CHANCE OF THUNDERSTORMS IN THE MOUNTAINS AND DESERTS EACH AFTERNOON AND EVENING. THE FLOW ALOFT REMAINS WEAK SO THUNDERSTORMS WILL BE SLOW MOVING AND COULD PRODUCE FLASH FLOODING IN THE MOUNTAINS AND ADJACENT DESERTS. AN ISOLATED SEVER THUNDERSTORM CANNOT BE RULED OUT. AN INTERMITTENT COASTAL EDDY SHOULD MAKE THE MARINE LAYER A LITTLE MORE EXTENSIVE. HOWEVER...THE MARINE LAYER WILL REMAIN FAIRLY SHALLOW WITH LOW CLOUDS AND FOG MOSTLY CONFINED TO THE COASTAL AREAS DURING THE NIGHTS AND MORNINGS. THE INCREASED MARINE INFLUENCE WILL BRING A LITTLE COOLING W OF THE MOUNTAINS. && .LONG TERM (TUE-FRI)... EXTENDED PROGS INDICATE NOT MUCH CHANGE IN THE GENERAL PATTERN AT LEAST THROUGH MID WEEK. THERE ARE SOME INDICATIONS OF A DRYING TREND TOWARD THE END OF NEXT WEEK WHICH WOULD RESULT IN A DECREASE IN THUNDERSTORM ACTIVITY. && .AVIATION... 271400Z...MARINE LAYER DEPTH THIS MORNING WAS LESS THAN 700 FEET BASED ON MDCRS SOUNDINGS. MARINE LAYER DEPTH WILL SHOW LITTLE CHANGE TODAY BUT MAY DEEPEN SLIGHTLY TONIGHT AND SATURDAY IN RESPONSE TO A DEVELOPING COASTAL EDDY. PATCHY STRATUS ALONG THE COAST WITH BASES AROUND 500 FEET MSL FROM CENTRAL SAN DIEGO COUNTY NORTH TO ORANGE COUNTY SHOULD BREAK UP BY 16Z. STRATUS SHOULD REFORM ALONG THE COAST THIS EVENING THEN PUSH LOCALLY INLAND TONIGHT. STRATUS SHOULD MOVE OVER KSAN BETWEEN 06Z AND 08Z TONIGHT. BASES COULD BE LOW ENOUGH TO BE BELOW LOCALIZER RUNWAY 27 MINIMUMS. STRATUS SHOULD CLEAR BY 16Z ON SATURDAY. ISOLATED THUNDERSTORMS ARE EXPECTED LATE THIS MORNING THROUGH SUNSET FOR THE MOUNTAINS AND ADJACENT DESERT AREAS FROM THE MEXICAN BORDER NORTH TO NEAR BIG BEAR LAKE. BASES COULD BE AS LOW AS FL080 WITH TOPS AT OR ABOVE FL400 AT TIMES. HORTON && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...DVA AVIATION...HORTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
255 PM CDT FRI JUL 27 2007 .DISCUSSION... 255 PM CDT WEAK SFC REFLECTION OF MID LVL S/WV TROF MOVG ACROSS NERN IL THIS AFTN...WITH WEAK LOW PRESSURE CENTER/CIRCULATION BETWEEN KORD AND KMDW AT 19Z. GOES VAPOR IMAGERY SHOWS MID LVL WAVE NICELY...WITH STRONG DRYING/SUBSIDENCE IN MID/UPPER LVLS DENOTED BY DARKENING IN IMAGERY OVER WI/NRN IL AND LK MICH. 88D CONTINUES TO SHOW WEAK ISOLATED CONVECTIVE SHOWERS TRYING TO DVLP...THOUGH COMBO OF PREVIOUSLY MENTIONED LARGE SCALE SUBSIDENCE...AND RELATIVELY WARM TEMP PROFILES WITH MINIMAL INSTABILITY PER CURRENT ACARS ASCENT/DESCENT SOUNDINGS FROM KORD...SUGGEST COVERAGE TO REMAIN ISOLATED WITH ONLY SHALLOW CONVECTIVE UPDRAFTS SUGGESTING LITTLE SUPPORT FOR THUNDER. EXPECT SHOWERS TO FADE WITH LOSS OF DIURNAL INSTABILITY TOWARD SUNSET...SO WILL MAINTAIN ISOLATED RW MENTION ONLY THROUGH EARLY EVENING. MAIN S/WV THEN CONTINUES OFF TO THE SOUTHEAST OVERNIGHT...WITH 20 METER 500 HPA HGT RISES. LLVL FLOW BECOMING NE AS SFC LOW/COLD FRONT SLIDES TOWARD OHIO VALLEY...THOUGH SFC DWPTS SLOW TO DROP OFF INITIALLY TONIGHT. FCST SOUNDINGS SUGGEST POTENTIAL FOR LAKE INDUCED STRATUS DVLPMNT WITH COOLING OF MOIST BOUNDARY LAYER. EXPECT SOME LINGERING STRATOCU SATURDAY WITH GRADUAL DRYING OF LLVLS...AND SECONDARY VORT/SPD MAX DROPPING FROM NRN PLAINS TOWARD MID MS VLY/WRN LAKES BY SAT NGT. CLOSED LOW OVER EASTERN LAKES FORECAST TO OPEN UP AND MOVE EAST WITH MAIN UPPER TROUGH AXIS DURG PERIOD...THOUGH GFS/NCEP ENSEMBLES AND 12Z ECMWF ALL TREND TOWARD FORMING ANOTHER CLOSED LOW ALONG EAST COAST AS S/WV ROUNDS ENTERS BASE OF TROF. MEANWHILE...UPPER RIDGE BUILDS ACROS NRN PLAINS/UPPER MIDWEST...WITH SFC HIGH PRESSURE GRADUALLY DRIFTING SOUTHEAST ACROSS WESTERN LAKES REGION THROUGH TUES. THUS PERIOD OF DRY WX WITH GRADUALLY DCRSG CLOUDS AND GRADUALLY WARMING TEMPS EXPECTED THROUGH MID NEXT WEEK FOR WFO LOT CWA. FCST 950/850 HPA TEMPS SUGGEST MAX TEMPS MODERATING FROM UPPER 70S/LOW 80S THIS WEEKEND...WITH LAKE INFLUENCE ON NELY WINDS...TO MID/UPPER 80S BY WED WITH AREAS NEAR LAKE MICH STILL SEEING DAILY LAKE BREEZE INFLUENCE IN WEAK SFC PRESSURE GRADIENT VCNTY SFC RIDGE. MEDIUM RANGE GUIDANCE INDICATES MORE AMPLIFIED S/WV TROF MOVG FROM WESTERN CANADA THROUGH ONT/HUDSON BAY BY MID WEEK...WHICH EVENTUALLY FLATTENS UPPER RIDGE ACROSS LAKES AND TRAILS WEAK SFC COLD FRONT INTO UPPER MIDWEST/NRN LAKES BY THURSDAY. AT THIS TIME...THURSDAY APPEARS TO BE WARMEST FOR NRN IL/IND AS LLVL THERMAL RIDGE GETS NUDGED SOUTHWARD ACROSS FCST AREA IN RESPONSE TO FLATTING OF UPPER RIDGE. HAVE BUMPED HPC NUMBERS JUST A BIT FOR MAXES THURSDAY AS LLVL FLOW BECOMES A LITTLE MORE SOUTHWEST WITH SFC RIDGE WEAKENING AND SLIDING OFF TO ESE...MORE ALONG 00Z MEX GUIDANCE WITH LOWER 90S FCST. FAIRLY GOOD AGREEMENT THAT WEAK SFC COLD FRONT TRAILING CANADIAN LOW PRESSURE WILL SAG INTO THE AREA LATE THURSDAY...THOUGH BECOMING STATIONARY ACROSS IL/IND ALONG SOUTHERN PERIPHERY OF FASTER ZONAL FLOW ALOFT FRI. APPEARS VERY WEAK SOUTHWARD PUSH TO FRONT THIS FAR SOUTH AT THIS GREAT DISTANCE...AND IN AGREEMENT WITH SURROUNDING WFOS HAVE MAINTAINED DRY FORECAST THRU FRIDAY. RATZER && .AVIATION... 1245PM CDT MAIN CONCERN FOR THE 18Z TAF PERIOD WILL SHIFT FROM PCPN POTENTIAL AND VISIBILITY TO CEILING ISSUES. CURRENTLY...A WEAK MID LEVEL CIRCULATION AND AN ASSOCIATED SURFACE LOW ON A COLD FRONT ARE PASSING THROUGH NERN IL. THE SYSTEM HAS ALREADY PASSED THROUGH THE RFD AREA AND WINDS THERE HAVE BEGUN TO SHIFT NELY. THE REMAINDER OF THE TAF SITES WILL FOLLOW SUIT WITHIN THE FIRST 1-2 HRS OF THE PERIOD. CEILINGS ACROSS THE REGION ARE A MIXED BAG OF IFR...MVFR AND VFR...WITH IFR LEVEL STRATO CU OCCASIONALLY GOING SCT. AS THE MID LEVEL CIRCULATION PASSES TO THE EAST...COOLER AIR ALOFT WILL FILTER OVER THE REGION AND CEILINGS WILL BECOME WIDESPREAD BKN-OVC...GRADUALLY LOWERING FROM LOWER RANGE MVFR TO IFR. THE LOWEST CEILINGS WILL BE NEAR THE LAKE FRONT AS NELY FLOW OFF THE LAKE WILL CONTINUE TO ENHANCE LOW LEVEL MOISTURE. WITH OVERNIGHT COOLING AND COPIOUS AMOUNTS OF LOW LEVEL MOISTURE IN PLACE...VISBY WILL ALSO LIKELY LOWER AGAIN TO 3-5SM...BUT WINDS ARND 10KT OVERNIGHT WILL LIKELY KEEP THE AIRMASS MIXED ENOUGH TO KEEP VISBY ABV IFR LEVELS. KREIN && .MARINE... 245 PM...A COLD FRONT IS CURRENTLY SWEEPING DOWN THE LAKE AND WILL REACH THE SOUTHERN TIP OF THE LAKE BY LATE TONIGHT. AS COOL HIGH PRESSURE BUILDS OVER THE UPPER PLAINS AND NRN LAKE MICHIGAN...WINDS WILL TURN NRLY AND INCREASE INTO THE 20-25KT RANGE. GIVEN THE LONG FETCH DOWN THE LAKE...WAVES SHOULD QUICKLY INCREASE TO 6-8 FEET OVERNIGHT. ON CHANGE TO THE PREVIOUS FORECAST PACKAGE IS TO DELAY THE BEGINNING OF THE SCA FOR THE NEARSHORE WATERS UNTIL 00Z THIS EVENING AS THE FRONT IS MOVING A LITTLE SLOWER THAN PREVIOUSLY ANTICIPATED. WINDS NOT EXPECTED TO CLIMB INTO GALE RANGES AS THE AIRMASS BEHIND THE FRONT IS NOT THAT COLD AND THE CENTRAL PRESSURE OF THE HIGH IS RELATIVELY WEAK. BY EARLY NEXT WEEK...THE HIGH WILL CONTINUE TO SAG OVER THE LAKE...DECREASING PRESSURE GRADIENTS AND DECREASING THE PRESSURE GRADIENT. THE HIGH SHOULD REMAIN NEARLY STATIONARY THROUGH MIDWEEK. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH UNTIL 23Z FRIDAY. IN...FLASH FLOOD WATCH UNTIL 23Z FRIDAY. LM...SCA 20Z TODAY UNTIL 03Z SUN ALL ILL AND IN SHORE && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
523 PM EDT FRI JUL 27 2007 .MESO UPDATE... SFC LAPS CAPE SHOWS MOST UNSTABLE AIR IS OVER OUR SERN CWA. STORMS MOSTLY WEAKENING NOW...WITH A LARGE MASS OF SHOWERS AND EMBEDDED THUNDERSTORMS OVER MUCH OF THE CWA...WHICH IS REALLY STABILIZING THE ATMS. DIGITAL VILS HAVE COME DOWN AS WELL...AND THE THREATS NOW REVOLVE AROUND CLARK COUNTY KY AND OTHER STORMS ACROSS THE SERN CWA. ALSO HAVE A FLASH FLOOD WARNING FOR TAYLOR COUNTY AS WE RECEIVED UP TO TWO INCHES OF RAINFALL IN UNDER AN HOUR. MONITORING OF THE ABOVE CONTINUES... WITH HIGH FREEZING HEIGHTS...THREATS NOW SEEM TO BE ABOUT ANOTHER HOUR OR TWO OF MARGINALLY SEVERE WINDS AND TORRENTIAL RAIN/MINOR FLOODING. OTHER STORMS HAVE DEVELOPED WELL UPSTREAM IN ACROSS IN/IL/MO. THESE ARE LIKELY DIURNALLY-DRIVEN...AND OUR ATMS WOULD BE WORKED OVER BY THE TIME THEY ARRIVE THAT I CAN ONLY SEE AN OVERALL SVR THREAT THROUGH ABOUT 700 PM EDT. CAN HOPEFULLY KNOCK OUT SOME COUNTIES OF THE WATCH AFTER THAT TIME FRAME. AL && .PREV DISCUSSION... SHORT TERM (TONIGHT AND SATURDAY)... ...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 02Z... STRONG SHORTWAVE DIVING DOWN FROM THE CHICAGO-LAND AREA HAS SPARKED SHOWERS AND STORMS ACROSS THE AREA (MCV VISIBLE IN REFLECTIVITY OVER CENTRAL IL). GIVEN MODERATE INSTABILITY AND GOOD DEEP-LAYER SHEAR (30 KTS FROM RECENT SDF ACARS SOUNDING AND AREA VWPS)...MARGINALLY SEVERE STORMS ARE POSSIBLE WITH DAMAGING WINDS AND LARGE HAIL BEING THE MAIN THREATS. THINK WIND RATHER THAN HAIL IS POSSIBLE GIVEN HIGH FREEZING AND WET-BULB HEIGHTS. WILL LIKELY BE ABLE TO CANCEL TIERS OF COUNTIES FROM NORTH TO SOUTH WITHIN THE WATCH AREA STARTING AT 6PM EDT OR SO. SHOWERS AND THUNDERSTORMS WILL LIKELY DIMINISH IN STRENGTH GREATLY AFTER 10 PM EDT...THOUGH STEADY RAIN WITH A FEW EMBEDDED STORMS ARE POSSIBLE THROUGHOUT THE OVERNIGHT HOURS. TRIMMED BACK POPS AFTER MIDNIGHT AS A RESULT...BUT STILL HAVE SLT TO LOW CHC POPS TOWARD MORNING. GIVEN AMPLE CLOUDS AND PRECIP...WENT ABOVE GUIDANCE FOR OVERNIGHT LOWS. AFTER MIDNIGHT...IT WILL LIKELY BECOME MORE OF AN AVIATION CONCERN...WITH MVFR/IFR CIGS AND VSBYS POSSIBLE. HAVE HINTED AT THIS IN THE TAFS ALREADY...AND MAY MENTION FOG OVERNIGHT TOWARD SAT MORN IN THE GRIDS/ZONES. TRAILING SYNOPTIC COOL FRONT WILL BE LOCATED NEAR THE OHIO RIVER BY 12Z SATURDAY. KEPT SLT CHC POPS IN FAR NRN CWA UNTIL 18Z SAT...WITH CHC POPS ELSEWHERE UNTIL 00Z SUN (HIGHEST POPS SOUTH UNTIL FRONT REACHES TN BORDER SATURDAY NIGHT). AM NOT EXPECTING SEVERE STORMS AT THIS TIME AS I FEEL MOST OF THE INSTABILITY WILL REMAIN SOUTH OF THE CWA. HAVE LOW 80S FOR HIGHS TOMORROW EVERYWHERE EXCEPT MID/UPPER 80S CLOSE TO TN BORDER. AL LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)... MAIN FORECAST CONCERNS FOR THE LONGER TERM WILL BE HOW FAST THE CLOUDS WILL DECREASE AFTER THE FRONT PUSHES THROUGH AND WILL ANY SHOWERS DEVELOP BEHIND THE FRONT ON SUNDAY. A TROUGH WILL PERSIST ALONG THE APPALACHIAN MOUNTAINS WITH A LARGE RIDGE SITTING OVER THE WEST HALF OF THE NATION THROUGH MUCH OF THE LONGER TERM PERIOD. BY THE END OF THE PERIOD THE TROUGH WEAKENS AND MOVES EAST AND THE UPPER RIDGE BECOMES BROADER AND EXTENDS EAST INTO THE LOWER OHIO VALLEY. GFS IS CONSISTENT WITH GFS ENSEMBLE...ECMWF AND UKMET AND WILL GENERALLY FOLLOW THE MODEL CONSENSUS. SATURDAY NIGHT THROUGH MONDAY NIGHT... THE COLD FRONT WILL EXIT THE REGION BY SATURDAY EVENING TAKING THE PRECIPITATION WITH IT. HOWEVER CLOUDS WILL LINGER OVER THE AREA SATURDAY NIGHT AND SUNDAY THEN DECREASE FROM THE NORTH SUNDAY NIGHT. A FEW SPRINKLES OR AN ISOLATED SHOWER COULD DEVELOP ACROSS OUR FAR SOUTHERN AND EASTERN COUNTIES DURING THE DAY SUNDAY...BUT FOR NOW WILL LEAVE ANY MENTION OF SPRINKLES OUT. BY MONDAY CLOUDS WILL PERSIST ONLY OVER THE FAR SOUTHERN AND EASTERN PARTS OF THE LMK FORECAST AREA. HIGH TEMPERATURES WILL BE IN THE UPPER 80S BOTH SUNDAY AND MONDAY. TUESDAY THROUGH FRIDAY... HIGH PRESSURE WILL BUILD INTO THE LOWER OHIO VALLEY TUESDAY. AT THE SAME TIME THE UPPER TROUGH WILL BE WEAKENING AND MOVING TO THE NORTHEAST. THIS WILL ALLOW HIGH PRESSURE TO SETTLE OVER THE OHIO VALLEY THROUGH THE REST OF THE WEEK. SKIES WILL STAY MOSTLY SUNNY DURING THE DAY AND MOSTLY CLEAR AT NIGHT. THERE WILL BE SOME INCREASE IN CLOUDS BY THE END OF THE WEEK BUT SUNSHINE WILL STILL BE DOMINANT DURING THE DAYTIME. TEMPERATURES WILL STAY QUITE WARM WITH HIGHS AROUND 90 AND LOWS IN THE MID AND UPPER 60S THROUGH THE END OF THE WEEK. SCHOLZ AVIATION (FOR 18Z TAFS)... FAIRLY STRONG UPPER-AIR DISTURBANCE OVER CHICAGO IS GENERATING A BATCH OF RAIN WITH EMBEDDED THUNDERSTORMS OVER CENTRAL IL/IN. CIGS WITHIN THIS AREA ARE GENERALLY IN THE LOW MVFR RANGE...WITH SOME AREAS SEEING DOWN TO LOW IFR CIGS AND IFR VSBYS FROM RA/BR. WILL TRY AND BEST TIME THIS IN AREA TAFS. AHEAD OF THIS PRECIP...WILL KEEP THE STEADY RAIN MORE ON THE MVFR SIDE OF THINGS AFTER 19Z AT SDF AND AFTER 20Z AT LEX. THINK THIS STEADY RAIN WILL BE NORTH OF THE BWG TAF SITE...AT WHICH POINT MORE OF AN ISLD-SCT T-STORM WOULD OCCUR OVER SRN KY. WILL HAVE MORE OF A VICINITY WORDING IN BWG UNTIL AFTER MIDNIGHT...AND THEN MAY INTRODUCE A PREVAILING RAIN GROUP. OTHERWISE...WITH AMPLE MOISTURE COULD HAVE BR AND MVFR-IFR VSBYS OVERNIGHT TOWARD SAT MORN. BL WINDS MAY BE BORDER-LINE LLWS CRITERIA AT BWG BETWEEN 06-12Z WITH 925MB WESTERLY WINDS OF 30 KTS...BUT WILL LEAVE THIS OUT FOR NOW AND SEE HOW THINGS PROGRESS. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
317 PM EDT FRI JUL 27 2007 .SHORT TERM (TONIGHT AND SATURDAY)... ...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 02Z... STRONG SHORTWAVE DIVING DOWN FROM THE CHICAGO-LAND AREA HAS SPARKED SHOWERS AND STORMS ACROSS THE AREA (MCV VISIBLE IN REFLECTIVITY OVER CENTRAL IL). GIVEN MODERATE INSTABILITY AND GOOD DEEP-LAYER SHEAR (30 KTS FROM RECENT SDF ACARS SOUNDING AND AREA VWPS)...MARGINALLY SEVERE STORMS ARE POSSIBLE WITH DAMAGING WINDS AND LARGE HAIL BEING THE MAIN THREATS. THINK WIND RATHER THAN HAIL IS POSSIBLE GIVEN HIGH FREEZING AND WET-BULB HEIGHTS. WILL LIKELY BE ABLE TO CANCEL TIERS OF COUNTIES FROM NORTH TO SOUTH WITHIN THE WATCH AREA STARTING AT 6PM EDT OR SO. SHOWERS AND THUNDERSTORMS WILL LIKELY DIMINISH IN STRENGTH GREATLY AFTER 10 PM EDT...THOUGH STEADY RAIN WITH A FEW EMBEDDED STORMS ARE POSSIBLE THROUGHOUT THE OVERNIGHT HOURS. TRIMMED BACK POPS AFTER MIDNIGHT AS A RESULT...BUT STILL HAVE SLT TO LOW CHC POPS TOWARD MORNING. GIVEN AMPLE CLOUDS AND PRECIP...WENT ABOVE GUIDANCE FOR OVERNIGHT LOWS. AFTER MIDNIGHT...IT WILL LIKELY BECOME MORE OF AN AVIATION CONCERN...WITH MVFR/IFR CIGS AND VSBYS POSSIBLE. HAVE HINTED AT THIS IN THE TAFS ALREADY...AND MAY MENTION FOG OVERNIGHT TOWARD SAT MORN IN THE GRIDS/ZONES. TRAILING SYNOPTIC COOL FRONT WILL BE LOCATED NEAR THE OHIO RIVER BY 12Z SATURDAY. KEPT SLT CHC POPS IN FAR NRN CWA UNTIL 18Z SAT...WITH CHC POPS ELSEWHERE UNTIL 00Z SUN (HIGHEST POPS SOUTH UNTIL FRONT REACHES TN BORDER SATURDAY NIGHT). AM NOT EXPECTING SEVERE STORMS AT THIS TIME AS I FEEL MOST OF THE INSTABILITY WILL REMAIN SOUTH OF THE CWA. HAVE LOW 80S FOR HIGHS TOMORROW EVERYWHERE EXCEPT MID/UPPER 80S CLOSE TO TN BORDER. AL .LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)... MAIN FORECAST CONCERNS FOR THE LONGER TERM WILL BE HOW FAST THE CLOUDS WILL DECREASE AFTER THE FRONT PUSHES THROUGH AND WILL ANY SHOWERS DEVELOP BEHIND THE FRONT ON SUNDAY. A TROUGH WILL PERSIST ALONG THE APPALACHIAN MOUNTAINS WITH A LARGE RIDGE SITTING OVER THE WEST HALF OF THE NATION THROUGH MUCH OF THE LONGER TERM PERIOD. BY THE END OF THE PERIOD THE TROUGH WEAKENS AND MOVES EAST AND THE UPPER RIDGE BECOMES BROADER AND EXTENDS EAST INTO THE LOWER OHIO VALLEY. GFS IS CONSISTENT WITH GFS ENSEMBLE...ECMWF AND UKMET AND WILL GENERALLY FOLLOW THE MODEL CONSENSUS. SATURDAY NIGHT THROUGH MONDAY NIGHT... THE COLD FRONT WILL EXIT THE REGION BY SATURDAY EVENING TAKING THE PRECIPITATION WITH IT. HOWEVER CLOUDS WILL LINGER OVER THE AREA SATURDAY NIGHT AND SUNDAY THEN DECREASE FROM THE NORTH SUNDAY NIGHT. A FEW SPRINKLES OR AN ISOLATED SHOWER COULD DEVELOP ACROSS OUR FAR SOUTHERN AND EASTERN COUNTIES DURING THE DAY SUNDAY...BUT FOR NOW WILL LEAVE ANY MENTION OF SPRINKLES OUT. BY MONDAY CLOUDS WILL PERSIST ONLY OVER THE FAR SOUTHERN AND EASTERN PARTS OF THE LMK FORECAST AREA. HIGH TEMPERATURES WILL BE IN THE UPPER 80S BOTH SUNDAY AND MONDAY. TUESDAY THROUGH FRIDAY... HIGH PRESSURE WILL BUILD INTO THE LOWER OHIO VALLEY TUESDAY. AT THE SAME TIME THE UPPER TROUGH WILL BE WEAKENING AND MOVING TO THE NORTHEAST. THIS WILL ALLOW HIGH PRESSURE TO SETTLE OVER THE OHIO VALLEY THROUGH THE REST OF THE WEEK. SKIES WILL STAY MOSTLY SUNNY DURING THE DAY AND MOSTLY CLEAR AT NIGHT. THERE WILL BE SOME INCREASE IN CLOUDS BY THE END OF THE WEEK BUT SUNSHINE WILL STILL BE DOMINANT DURING THE DAYTIME. TEMPERATURES WILL STAY QUITE WARM WITH HIGHS AROUND 90 AND LOWS IN THE MID AND UPPER 60S THROUGH THE END OF THE WEEK. SCHOLZ && .AVIATION (FOR 18Z TAFS)... FAIRLY STRONG UPPER-AIR DISTURBANCE OVER CHICAGO IS GENERATING A BATCH OF RAIN WITH EMBEDDED THUNDERSTORMS OVER CENTRAL IL/IN. CIGS WITHIN THIS AREA ARE GENERALLY IN THE LOW MVFR RANGE...WITH SOME AREAS SEEING DOWN TO LOW IFR CIGS AND IFR VSBYS FROM RA/BR. WILL TRY AND BEST TIME THIS IN AREA TAFS. AHEAD OF THIS PRECIP...WILL KEEP THE STEADY RAIN MORE ON THE MVFR SIDE OF THINGS AFTER 19Z AT SDF AND AFTER 20Z AT LEX. THINK THIS STEADY RAIN WILL BE NORTH OF THE BWG TAF SITE...AT WHICH POINT MORE OF AN ISLD-SCT T-STORM WOULD OCCUR OVER SRN KY. WILL HAVE MORE OF A VICINITY WORDING IN BWG UNTIL AFTER MIDNIGHT...AND THEN MAY INTRODUCE A PREVAILING RAIN GROUP. OTHERWISE...WITH AMPLE MOISTURE COULD HAVE BR AND MVFR-IFR VSBYS OVERNIGHT TOWARD SAT MORN. BL WINDS MAY BE BORDER-LINE LLWS CRITERIA AT BWG BETWEEN 06-12Z WITH 925MB WESTERLY WINDS OF 30 KTS...BUT WILL LEAVE THIS OUT FOR NOW AND SEE HOW THINGS PROGRESS. AL && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
108 PM EDT FRI JUL 27 2007 .AVIATION (FOR 18Z TAFS)... FAIRLY STRONG UPPER-AIR DISTURBANCE OVER CHICAGO IS GENERATING A BATCH OF RAIN WITH EMBEDDED THUNDERSTORMS OVER CENTRAL IL/IN. CIGS WITHIN THIS AREA ARE GENERALLY IN THE LOW MVFR RANGE...WITH SOME AREAS SEEING DOWN TO LOW IFR CIGS AND IFR VSBYS FROM RA/BR. WILL TRY AND BEST TIME THIS IN AREA TAFS. AHEAD OF THIS PRECIP...WILL KEEP THE STEADY RAIN MORE ON THE MVFR SIDE OF THINGS AFTER 19Z AT SDF AND AFTER 20Z AT LEX. THINK THIS STEADY RAIN WILL BE NORTH OF THE BWG TAF SITE...AT WHICH POINT MORE OF AN ISLD-SCT T-STORM WOULD OCCUR OVER SRN KY. WILL HAVE MORE OF A VICINITY WORDING IN BWG UNTIL AFTER MIDNIGHT...AND THEN MAY INTRODUCE A PREVAILING RAIN GROUP. OTHERWISE...WITH AMPLE MOISTURE COULD HAVE BR AND MVFR-IFR VSBYS OVERNIGHT TOWARD SAT MORN. BL WINDS MAY BE BORDER-LINE LLWS CRITERIA AT BWG BETWEEN 06-12Z WITH 925MB WESTERLY WINDS OF 30 KTS...BUT WILL LEAVE THIS OUT FOR NOW AND SEE HOW THINGS PROGRESS. AL && .PREVIOUS DISCUSSION BELOW... MORNING UPDATE... DOING A QUICK UPDATE TODAY TO LOWER MAX TEMPS ACROSS THE EAST A COUPLE OF DEGREES BASED ON MORNING SHOWERS/STORMS. STRONG SHORTWAVE AND MCV CAN BE SEEN NEAR MILWAUKEE/CHICAGO FROM WATER VAPOR AND VIS SAT RESPECTIVELY. DRY AIR ALOFT AND FASTER 500MB WINDS FROM THE DISTURBANCE WILL HELP DESTABILIZE THE ATMOSPHERE AS WELL AS INCREASE DEEP-LAYER SHEAR. THESE SHOULD COMBINE TO CREATE A MARGINALLY-SEVERE ATMOSPHERE TODAY. OUR NERN HALF OF THE CWA MAY BE A BIT WORKED-OVER FROM THE MORNING PRECIP BASED ON CURRENT SDF ACARS SOUNDING...BUT THERE ARE BREAKS IN THE CLOUDS SO INSTABILITY SHOULD INCREASE INTO THE EARLY AFTERNOON HOURS. AND ACTUALLY A FEW SMALL CELLS ARE ALREADY DEVELOPING OVER CENTRAL-SOUTHERN INDIANA AND SOUTHERN OHIO. FORECAST SOUNDINGS HOWEVER ARE NOT THAT IMPRESSIVE...BUT SHOULD BE ENOUGH TO YIELD MARGINALLY SEVERE HAIL/WINDS THIS AFTERNOON AND EVENING. THE DAY ONE OUTLOOK FROM SPC LOOKS PRETTY GOOD...THOUGH I THINK EVEN SRN KY COULD SEE SOME SEVERE BECAUSE OF THE HIGHER INSTABILITY IN THAT REGION. OTHERWISE...THE FORECAST IS IN GOOD SHAPE. HAVE LIKELY POPS ACROSS SRN IN DOWN TO 40 POPS ACROSS SRN KY. UPDATE OUT SHORTLY. AL SHORT TERM (TODAY AND TONIGHT)... THUNDERSTORM POTENTIAL THIS MORNING AND AGAIN LATER THIS AFTERNOON AND TONIGHT IS THE MAIN WEATHER PROBLEM FOR THE SHORT TERM PERIOD. FIRST WE HAVE TO DEAL WITH SCATTERED TRW/RW THAT DEVELOPED DURING THE PAST TWO OR THREE HOURS TO OUR WEST AND NORTHWEST THAT WILL LIKELY MOVE TO THE ESE ACROSS PORTIONS OF NORTH CENTRAL KENTUCKY AND SOUTH CENTRAL INDIANA THIS MORNING. MODELS DO SHOW SOME INCREASING LOW LEVEL CONVERGENCE ACROSS THIS AREA INTO THE MORNING HOURS AS THE LOW LEVEL FLOW INCREASES TO OUR WEST IN ADVANCE OF AN APPROACHING SHORT WAVE OFF TO OUR NORTHWEST. LATER TODAY INTO TONIGHT THE SHORT SHORT WAVE SWEEPS BY TO OUR NORTHEAST AND COMBINED WITH ITS ASSOCIATED FRONTAL SYSTEM... IN COMBINATION WITH DAYTIME HEATING...AND RATHER HIGH SFC DEWPOINTS NEAR 70...SHOULD TRIGGER MORE NUMEROUS SHOWERS AND THUNDERSTORMS. SOME OF THE STORMS COULD BE STRONG OR LOCALLY SEVERE...ESPECIALLY ACROSS SOUTH CENTRAL INDIANA AND PORTIONS OF NORTH CENTRAL AND EAST CENTRAL KENTUCKY. HPC QPF TRENDS EXCEPT FOR THIS MORNING LOOKED OK AND WILL BE USED FOR THE SHORT TERM. AS FOR TEMP TRENDS MORE LESS PERSISTENCE WITH THE CURRENT TRENDS AND THAT AGREES WITH THE PREFERRED NEW MAV FCSTS. --21 LONG TERM (SATURDAY THROUGH THURSDAY)... SATURDAY THROUGH SUNDAY NIGHT... MAIN FORECAST PROBLEM DURING THIS PD WILL BE RAIN CHANCES ON SATURDAY AS FRONTAL BOUNDARY CONTINUES TO PUSH THROUGH THE REGION. LATEST MODEL SOLUTIONS CONTINUE TO BE IN GOOD AGREEMENT WITH FRONTAL BOUNDARY WORKING THROUGH THE STATE ON SATURDAY. RESIDUAL CONVECTION WILL BE LIKELY ONGOING AT THE BEGINNING OF THE PD ACROSS MUCH OF THE AREA...BUT MAIN CONCENTRATION OF ACTIVITY WILL ACROSS OUR EASTERN AND SOUTHERN SECTIONS. THUS...WILL MAINTAIN MOSTLY CLOUDY SKIES WITH CHC POPS THROUGH THE DAY. MODEL TIME-HEIGHT PLOTS SHOW DECENT DRYING COMING IN SAT NIGHT WHICH SHOULD END PRECIP ACROSS THE REGION. TEMPERATURES WILL REMAIN WARM ON SAT WITH READINGS OF 82 TO 87 AND LOWS IN THE MID 60S BY SUN MORNING. UPPER LEVEL AND SFC RIDGE ARE FORECAST TO BUILD INTO THE REGION ON SUNDAY BRINGING DRY WEATHER TO MUCH OF THE FA. HIGHS WILL A COUPLE OF DEGREES WARMER ON SUNDAY WITH HIGHS OF 83 TO 88. MONDAY THROUGH THURSDAY... CURRENT FCST THROUGH THIS TIME PERIOD IS IN GOOD SHAPE AT THIS TIME. LATEST MODEL CONSENSUS CONTINUES TO TREND CLOSE TO PREVIOUS MODEL RUNS FROM THU MORNING/AFTERNOON. BELT OF WESTERLIES WILL REMAIN WELL NORTH OF THE REGION WITH A BAGGY H5 TROF REMAINING ENTRENCHED ACROSS THE U.S. EAST COAST. UPSTREAM H5 RIDGE IS FCST TO EXPAND SLOWLY AND CREEP EASTWARD INTO THE WESTERN OHIO VALLEY DURING THE PD. SENSIBLE WEATHER WOULD BE DRY WITH MODERATING TEMPERATURES THROUGH THE PD. CURRENT FCST HANDLES THIS QUITE WELL AND ONLY MADE SOME MINOR ADJUSTMENTS IN THE MON/TUE TIME FRAME. -MJ && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
306 PM MDT FRI JUL 27 2007 .DISCUSSION... COMPLICATED PATTERN CONTINUES TO EVOLVE OVER NM AND THE CONVECTIVE COMPLEXES DEVELOPING FROM DAY TO DAY MAKE IT DIFFICULT TO ANALYZE HOW WELL MODEL SOLUTIONS HANDLE EVEN THE NEXT 48 HOURS. THE WATER VAPOR LOOP THIS AFTERNOON SHOWS AN UPPER WAVE OVER TX SHEARING NW INTO THE NE QUADRANT OF NM DEFORMING THE MOISTURE PLUME OVER NORTHERN NM AND COLORADO. 400-250MB AIRCRAFT WIND DATA SHOWS THE 40-60 KNOT JET PUSHING INTO SE CO ALONG THE NORTHERN PERIPHERY OF THE UPPER LOW. SHOWERS AND STORMS HAVE DEVELOPED OVER THE ESTANCIA VALLEY AND WESTERN MTNS. ACTIVITY OVER THE ESTANCIA VALLEY WILL LIKELY CONTINUE MOVING SLOWLY WEST AROUND 5 TO 10 MPH THIS EVE INTO THE SANDIA... MANZANO...AND JEMEZ MTNS AND PERHAPS THE RIO GRANDE VALLEY. 12Z GUIDANCE SHOWS THE UPPER WAVE CONTINUING TO PUSH WEST TOWARD NM SHOVING THE MAIN MOISTURE PLUME INTO THE SW MTNS AND SE AZ. THINK THE BEST THREAT FOR FLASH FLOODING IS OVER THE SW MTNS WITH WEAK STORM MOTION...PWATS FORECAST AROUND 1.5 INCHES...AND DECENT MOISTURE CONVERGENCE. HOWEVER...CONFIDENCE IS TOO LOW TO HOIST A WATCH SINCE UPPER WAVE HAS BEEN A COMPLICATING FACTOR FOR THE PAST SEVERAL DAYS IN THE MODELS AND CONVECTION HAS BEEN MEAGER TO SUSTAIN ITSELF AFTER DARK. 15Z SREF/12Z MREF MEMBERS DO SHOW THE UPPER WAVE PUSHING WEST ACROSS THE SOUTHERN HALF OF NM THROUGH MONDAY AND TUESDAY. IF THE UPPER WAVE MAINTAINS ITSELF THROUGH THIS PERIOD WE MAY STILL SEE A DECENT SOUTH TO NORTH PLUME SET UP OVER THE STATE NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 64 89 65 90 / 40 30 30 20 GALLUP.......................... 58 84 56 84 / 60 40 30 30 GRANTS.......................... 55 83 55 84 / 40 30 30 30 GLENWOOD........................ 59 88 60 88 / 50 50 40 40 CHAMA........................... 48 77 48 79 / 40 50 40 40 LOS ALAMOS...................... 56 83 55 81 / 30 30 40 40 RED RIVER....................... 46 71 45 70 / 30 50 60 50 TAOS............................ 49 83 52 82 / 30 30 40 40 SANTA FE........................ 56 86 57 83 / 40 30 40 40 SANTA FE AIRPORT................ 57 87 57 85 / 40 30 40 40 ESPANOLA........................ 59 89 59 87 / 30 30 40 30 ALBUQUERQUE HEIGHTS............. 65 90 67 88 / 50 20 40 30 ALBUQUERQUE VALLEY.............. 64 92 66 90 / 50 20 40 30 ALBUQUERQUE FOOTHILLS........... 62 88 68 86 / 50 30 40 30 ALBUQUERQUE WEST MESA........... 64 90 67 89 / 50 20 40 30 SOCORRO......................... 65 91 65 91 / 50 20 30 30 SANDIA PARK/CEDAR CREST......... 55 83 57 79 / 40 40 40 40 MORIARTY/ESTANCIA............... 52 88 53 85 / 40 20 30 30 CARRIZOZO....................... 62 87 63 85 / 40 20 20 20 RUIDOSO......................... 54 78 55 75 / 40 30 30 30 RATON........................... 55 84 55 82 / 20 30 40 40 LAS VEGAS....................... 54 83 53 80 / 30 20 40 30 ROY............................. 59 87 60 83 / 20 20 30 30 CLAYTON......................... 61 91 62 87 / 10 10 20 30 SANTA ROSA...................... 63 92 63 89 / 20 10 20 20 TUCUMCARI....................... 65 94 65 91 / 10 10 10 20 FORT SUMNER..................... 65 93 66 89 / 10 10 20 20 CLOVIS.......................... 63 91 63 89 / 10 10 10 20 PORTALES........................ 64 90 64 90 / 20 10 10 20 ROSWELL......................... 68 94 69 92 / 20 10 20 20 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ GUYER