Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/07/13


AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1036 AM CDT MON AUG 5 2013 .UPDATE... IN THE NEAR TERM...WILL CONTINUE TO MONITOR CONVECTIVE TRENDS ACROSS NORTHEAST SECTIONS FOR EXCESSIVE RAINFALL POTENTIAL. EXPECT ADDITIONAL DEVELOPMENT ACROSS MOST AREAS THIS AFTERNOON...AS SMALL SCALE BOUNDARIES ACT ON A VERY UNSTABLE ATMOSPHERIC COLUMN. 55 && .PREV DISCUSSION... /ISSUED 641 AM CDT MON AUG 5 2013/ AVIATION... NORTHWEST FLOW WILL BRING A SHORT WAVE ACROSS THE AREA TODAY WITH SHOWERS AND THUNDERSTORMS. PRECIPITATION IS SCATTERED ACROSS THE NORTHEAST HALF OF THE STATE. AN MCS IS EXPECTED TO DEVELOP TONIGHT IN KANSAS AND MOVE INTO NORTH ARKANSAS AGAIN TUESDAY MORNING. HIGH PRESSURE AND DRY WEATHER IS EXPECTED FOR WEDNESDAY...BUT THE ACTIVE WEATHER PATTERN WILL RETURN FOR THURSDAY AND THROUGH THE WEEKEND. PREV DISCUSSION... /ISSUED 334 AM CDT MON AUG 5 2013/ DISCUSSION... DIFFERENT DAY...SAME FORECAST. MAIN CONCERNS REMAIN CHANCES OF CONVECTION WITH THUNDERSTORM COMPLEXES MOVING ACROSS AR...MAINLY TODAY AND TUESDAY...WITH POSSIBLE HEAVY RAIN THREAT AND FLASH FLOODING POTENTIAL. TEMPERATURE FORECAST WILL BE LOWER THAN NORMAL OVER NORTHERN AR...WHILE AROUND NORMAL TO A BIT ABOVE SOUTHERN AREAS. LOWER RAIN CHANCES EXPECTED WEDNESDAY AND THURSDAY. MAIN CONVECTION TONIGHT HAS BEEN FOCUSED OVER EASTERN KS TO MO...WITH LIGHT CONVECTION OVER EASTERN OK TO NORTHERN AR. TONIGHT HAVE SEEN THE MCV AHEAD OF LAST NIGHT...AND CONVECTION HAS MADE IT TO NORTHERN AR. ALSO DID SEE CONVECTION HELPED WITH THE WEAK WARM FRONT OVER SOUTHERN AR. THIS MORNING IT REMAINS OVER OVER SOUTHERN AR WHERE SOUTH OF THE BOUNDARY DEW POINT TEMPS WERE IN THE MID 70S...WHILE MAINLY LOWER 70S THE REST OF AR. 00Z SOUNDING AT KLZK AND KSGF CONTINUED THE PRECIP WATER VALUE AROUND 2 INCHES AND UNSTABLE. A LOW LEVEL JET WAS EVIDENT INTO EASTERN KS TO EASTERN OK...THEN INTO SW MO. THE UPPER NW PATTERN CONTINUES INTO THE REGION...WITH THE LATEST SHORT WAVE MOVING OVER THE OZARKS OF OK...MO TO AR. ADDITIONAL ENERGY WAS SEEN UPSTREAM WHICH WILL AFFECT THE REGION MONDAY NIGHT. RAINS OVER NORTHERN AR WERE LOWER THAN PREVIOUS DAY BUT OVERALL VALUES OVER THE LAST SEVERAL DAYS ARE 1 TO 3 INCHES. SO FLASH FLOOD WATCH WILL BE IN AFFECT THROUGH MONDAY NIGHT...WITH THE POTENTIAL FOR FLASH FLOODING WITH HEAVY RAIN. SHORT TERM...TODAY THROUGH THURSDAY NIGHT TODAY`S FORECAST WILL START WITH A HIGH POP OVER NORTHERN AR DUE TO ON GOING CONVECTION. THE FLASH WATCH WILL CONTINUE THROUGH AT LEAST TONIGHT WITH MODELS SHOWING ANOTHER MCV EXPECTED TO AFFECT PARTS OF NORTHERN AR. WRF AND HRRR MODELS ARE A BIT DIFFERENT IN THEIR SOLUTIONS EARLY TODAY...AND LIKE HRRR BASED ON ON GOING TRENDS. MAIN SURGE OF CONVECTION WILL CONTINUE OVER NORTHERN TO PARTS OF NORTHERN CENTRAL AR TODAY...WITH A E TO SE MOVEMENT AS IT MOVES FROM KS AND MO...THEN INTO AR. PRECIP WATER VALUES REMAIN AROUND 2 INCHES OR MORE...AND STORMS WILL PRODUCE HEAVY RAIN. FLASH FLOOD WATCH THOSE AREAS THAT HAVE RECEIVED RAIN OVER THE LAST FEW DAYS AND WHERE TODAY`S HEAVY RAIN BAND WILL BE. LATER TODAY THE MCV MOVES EAST OF AR...THEN TONIGHT THE UPPER RIDGE IS FORECAST TO BUILD A BIT MORE EAST...AND TAKE THE NEXT COMPLEX MORE NORTH TO EAST...WHICH WILL AFFECT MORE N TO NE AR. THIS HOLDS INTO TUESDAY WITH FORECAST POP MORE OVER N TO NE AR. STILL SOME CHANCE WILL BE OVER MUCH OF THE STATE...BUT SHOULD BE LOWER. TUESDAY NIGHT TO WEDNESDAY AND THURSDAY...CONVECTION IS ALSO EXPECTED TO BE MORE FOCUSED OVER NORTHERN AR WITH MODEL FORECAST SHORT WAVE ENERGY. A FLASH FLOOD WATCH WILL PROBABLY BE DROP LATER TUESDAY TO WEDNESDAY BUT MAY HAVE TO BE CONSIDERED IF MORE HEAVY CONVECTION IS ANTICIPATED. OTHERWISE TEMPERATURES WILL GRADUALLY WARM INTO MID WEEK AS THE UPPER RIDGE LOWERS RAIN CHANCES A BIT AND THE HEAT OVER TEXAS MOVES INTO AR. LONG TERM...FRIDAY THROUGH SUNDAY UPPER LEVEL HIGH PRESSURE WILL BE OVER ARKANSAS THROUGH THE LONG TERM PERIOD. ALSO...THE HIGH WILL STRENGTHEN NORTHWEST INTO THE NORTHERN ROCKIES. A COLD FRONT WILL MOVE INTO NORTH ARKANSAS FRIDAY AND STALL. THE FRONT SHOULD HANG AROUND NORTH ARKANSAS THROUGH THE WEEKEND. THIS WILL KEEP CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST WITH BEST CHANCES IN THE NORTH THROUGH THE PERIOD. THE HIGH PRESSURE MAY SHIFT WESTWARD SUNDAY AND PROVIDE MORE OF A NORTHWEST FLOW AND BETTER CHANCES OF PRECIPITATION. NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 86 72 91 73 / 80 30 30 20 CAMDEN AR 94 76 97 75 / 50 10 10 10 HARRISON AR 88 72 91 72 / 90 30 20 20 HOT SPRINGS AR 93 74 95 74 / 40 20 10 10 LITTLE ROCK AR 90 74 94 75 / 60 20 20 10 MONTICELLO AR 93 76 96 76 / 50 10 10 10 MOUNT IDA AR 94 74 96 74 / 40 10 10 10 MOUNTAIN HOME AR 87 71 90 72 / 90 30 30 20 NEWPORT AR 86 73 91 74 / 60 30 30 20 PINE BLUFF AR 91 75 95 75 / 50 20 20 10 RUSSELLVILLE AR 90 73 94 74 / 60 20 20 20 SEARCY AR 88 74 92 74 / 60 20 20 20 STUTTGART AR 90 75 94 75 / 60 20 20 10 && .LZK WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR BAXTER-BOONE- CLEBURNE-FULTON-INDEPENDENCE-IZARD-JOHNSON-MARION-NEWTON-POPE- SEARCY-SHARP-STONE-VAN BUREN. && $$ AVIATION...99
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
641 AM CDT MON AUG 5 2013 .AVIATION... NORTHWEST FLOW WILL BRING A SHORT WAVE ACROSS THE AREA TODAY WITH SHOWERS AND THUNDERSTORMS. PRECIPITATION IS SCATTERED ACROSS THE NORTHEAST HALF OF THE STATE. AN MCS IS EXPECTED TO DEVELOP TONIGHT IN KANSAS AND MOVE INTO NORTH ARKANSAS AGAIN TUESDAY MORNING. HIGH PRESSURE AND DRY WEATHER IS EXPECTED FOR WEDNESDAY...BUT THE ACTIVE WEATHER PATTERN WILL RETURN FOR THURSDAY AND THROUGH THE WEEKEND. && .PREV DISCUSSION... /ISSUED 334 AM CDT MON AUG 5 2013/ DISCUSSION... DIFFERENT DAY...SAME FORECAST. MAIN CONCERNS REMAIN CHANCES OF CONVECTION WITH THUNDERSTORM COMPLEXES MOVING ACROSS AR...MAINLY TODAY AND TUESDAY...WITH POSSIBLE HEAVY RAIN THREAT AND FLASH FLOODING POTENTIAL. TEMPERATURE FORECAST WILL BE LOWER THAN NORMAL OVER NORTHERN AR...WHILE AROUND NORMAL TO A BIT ABOVE SOUTHERN AREAS. LOWER RAIN CHANCES EXPECTED WEDNESDAY AND THURSDAY. MAIN CONVECTION TONIGHT HAS BEEN FOCUSED OVER EASTERN KS TO MO...WITH LIGHT CONVECTION OVER EASTERN OK TO NORTHERN AR. TONIGHT HAVE SEEN THE MCV AHEAD OF LAST NIGHT...AND CONVECTION HAS MADE IT TO NORTHERN AR. ALSO DID SEE CONVECTION HELPED WITH THE WEAK WARM FRONT OVER SOUTHERN AR. THIS MORNING IT REMAINS OVER OVER SOUTHERN AR WHERE SOUTH OF THE BOUNDARY DEW POINT TEMPS WERE IN THE MID 70S...WHILE MAINLY LOWER 70S THE REST OF AR. 00Z SOUNDING AT KLZK AND KSGF CONTINUED THE PRECIP WATER VALUE AROUND 2 INCHES AND UNSTABLE. A LOW LEVEL JET WAS EVIDENT INTO EASTERN KS TO EASTERN OK...THEN INTO SW MO. THE UPPER NW PATTERN CONTINUES INTO THE REGION...WITH THE LATEST SHORT WAVE MOVING OVER THE OZARKS OF OK...MO TO AR. ADDITIONAL ENERGY WAS SEEN UPSTREAM WHICH WILL AFFECT THE REGION MONDAY NIGHT. RAINS OVER NORTHERN AR WERE LOWER THAN PREVIOUS DAY BUT OVERALL VALUES OVER THE LAST SEVERAL DAYS ARE 1 TO 3 INCHES. SO FLASH FLOOD WATCH WILL BE IN AFFECT THROUGH MONDAY NIGHT...WITH THE POTENTIAL FOR FLASH FLOODING WITH HEAVY RAIN. SHORT TERM...TODAY THROUGH THURSDAY NIGHT TODAY`S FORECAST WILL START WITH A HIGH POP OVER NORTHERN AR DUE TO ON GOING CONVECTION. THE FLASH WATCH WILL CONTINUE THROUGH AT LEAST TONIGHT WITH MODELS SHOWING ANOTHER MCV EXPECTED TO AFFECT PARTS OF NORTHERN AR. WRF AND HRRR MODELS ARE A BIT DIFFERENT IN THEIR SOLUTIONS EARLY TODAY...AND LIKE HRRR BASED ON ON GOING TRENDS. MAIN SURGE OF CONVECTION WILL CONTINUE OVER NORTHERN TO PARTS OF NORTHERN CENTRAL AR TODAY...WITH A E TO SE MOVEMENT AS IT MOVES FROM KS AND MO...THEN INTO AR. PRECIP WATER VALUES REMAIN AROUND 2 INCHES OR MORE...AND STORMS WILL PRODUCE HEAVY RAIN. FLASH FLOOD WATCH THOSE AREAS THAT HAVE RECEIVED RAIN OVER THE LAST FEW DAYS AND WHERE TODAY`S HEAVY RAIN BAND WILL BE. LATER TODAY THE MCV MOVES EAST OF AR...THEN TONIGHT THE UPPER RIDGE IS FORECAST TO BUILD A BIT MORE EAST...AND TAKE THE NEXT COMPLEX MORE NORTH TO EAST...WHICH WILL AFFECT MORE N TO NE AR. THIS HOLDS INTO TUESDAY WITH FORECAST POP MORE OVER N TO NE AR. STILL SOME CHANCE WILL BE OVER MUCH OF THE STATE...BUT SHOULD BE LOWER. TUESDAY NIGHT TO WEDNESDAY AND THURSDAY...CONVECTION IS ALSO EXPECTED TO BE MORE FOCUSED OVER NORTHERN AR WITH MODEL FORECAST SHORT WAVE ENERGY. A FLASH FLOOD WATCH WILL PROBABLY BE DROP LATER TUESDAY TO WEDNESDAY BUT MAY HAVE TO BE CONSIDERED IF MORE HEAVY CONVECTION IS ANTICIPATED. OTHERWISE TEMPERATURES WILL GRADUALLY WARM INTO MID WEEK AS THE UPPER RIDGE LOWERS RAIN CHANCES A BIT AND THE HEAT OVER TEXAS MOVES INTO AR. LONG TERM...FRIDAY THROUGH SUNDAY UPPER LEVEL HIGH PRESSURE WILL BE OVER ARKANSAS THROUGH THE LONG TERM PERIOD. ALSO...THE HIGH WILL STRENGTHEN NORTHWEST INTO THE NORTHERN ROCKIES. A COLD FRONT WILL MOVE INTO NORTH ARKANSAS FRIDAY AND STALL. THE FRONT SHOULD HANG AROUND NORTH ARKANSAS THROUGH THE WEEKEND. THIS WILL KEEP CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST WITH BEST CHANCES IN THE NORTH THROUGH THE PERIOD. THE HIGH PRESSURE MAY SHIFT WESTWARD SUNDAY AND PROVIDE MORE OF A NORTHWEST FLOW AND BETTER CHANCES OF PRECIPITATION. NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 86 72 91 73 / 80 30 30 20 CAMDEN AR 94 76 97 75 / 50 10 10 10 HARRISON AR 88 72 91 72 / 90 30 20 20 HOT SPRINGS AR 93 74 95 74 / 40 20 10 10 LITTLE ROCK AR 90 74 94 75 / 60 20 20 10 MONTICELLO AR 93 76 96 76 / 50 10 10 10 MOUNT IDA AR 94 74 96 74 / 40 10 10 10 MOUNTAIN HOME AR 87 71 90 72 / 90 30 30 20 NEWPORT AR 86 73 91 74 / 60 30 30 20 PINE BLUFF AR 91 75 95 75 / 50 20 20 10 RUSSELLVILLE AR 90 73 94 74 / 60 20 20 20 SEARCY AR 88 74 92 74 / 60 20 20 20 STUTTGART AR 90 75 94 75 / 60 20 20 10 && .LZK WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS EVENING FOR BAXTER-BOONE-CLEBURNE- FULTON-INDEPENDENCE-IZARD-JOHNSON-MARION-NEWTON-POPE-SEARCY- SHARP-STONE-VAN BUREN. && $$ AVIATION...51
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
334 AM CDT MON AUG 5 2013 .DISCUSSION... DIFFERENT DAY...SAME FORECAST. MAIN CONCERNS REMAIN CHANCES OF CONVECTION WITH THUNDERSTORM COMPLEXES MOVING ACROSS AR...MAINLY TODAY AND TUESDAY...WITH POSSIBLE HEAVY RAIN THREAT AND FLASH FLOODING POTENTIAL. TEMPERATURE FORECAST WILL BE LOWER THAN NORMAL OVER NORTHERN AR...WHILE AROUND NORMAL TO A BIT ABOVE SOUTHERN AREAS. LOWER RAIN CHANCES EXPECTED WEDNESDAY AND THURSDAY. MAIN CONVECTION TONIGHT HAS BEEN FOCUSED OVER EASTERN KS TO MO...WITH LIGHT CONVECTION OVER EASTERN OK TO NORTHERN AR. TONIGHT HAVE SEEN THE MCV AHEAD OF LAST NIGHT...AND CONVECTION HAS MADE IT TO NORTHERN AR. ALSO DID SEE CONVECTION HELPED WITH THE WEAK WARM FRONT OVER SOUTHERN AR. THIS MORNING IT REMAINS OVER OVER SOUTHERN AR WHERE SOUTH OF THE BOUNDARY DEW POINT TEMPS WERE IN THE MID 70S...WHILE MAINLY LOWER 70S THE REST OF AR. 00Z SOUNDING AT KLZK AND KSGF CONTINUED THE PRECIP WATER VALUE AROUND 2 INCHES AND UNSTABLE. A LOW LEVEL JET WAS EVIDENT INTO EASTERN KS TO EASTERN OK...THEN INTO SW MO. THE UPPER NW PATTERN CONTINUES INTO THE REGION...WITH THE LATEST SHORT WAVE MOVING OVER THE OZARKS OF OK...MO TO AR. ADDITIONAL ENERGY WAS SEEN UPSTREAM WHICH WILL AFFECT THE REGION MONDAY NIGHT. RAINS OVER NORTHERN AR WERE LOWER THAN PREVIOUS DAY BUT OVERALL VALUES OVER THE LAST SEVERAL DAYS ARE 1 TO 3 INCHES. SO FLASH FLOOD WATCH WILL BE IN AFFECT THROUGH MONDAY NIGHT...WITH THE POTENTIAL FOR FLASH FLOODING WITH HEAVY RAIN. && .SHORT TERM...TODAY THROUGH THURSDAY NIGHT TODAY`S FORECAST WILL START WITH A HIGH POP OVER NORTHERN AR DUE TO ON GOING CONVECTION. THE FLASH WATCH WILL CONTINUE THROUGH AT LEAST TONIGHT WITH MODELS SHOWING ANOTHER MCV EXPECTED TO AFFECT PARTS OF NORTHERN AR. WRF AND HRRR MODELS ARE A BIT DIFFERENT IN THEIR SOLUTIONS EARLY TODAY...AND LIKE HRRR BASED ON ON GOING TRENDS. MAIN SURGE OF CONVECTION WILL CONTINUE OVER NORTHERN TO PARTS OF NORTHERN CENTRAL AR TODAY...WITH A E TO SE MOVEMENT AS IT MOVES FROM KS AND MO...THEN INTO AR. PRECIP WATER VALUES REMAIN AROUND 2 INCHES OR MORE...AND STORMS WILL PRODUCE HEAVY RAIN. FLASH FLOOD WATCH THOSE AREAS THAT HAVE RECEIVED RAIN OVER THE LAST FEW DAYS AND WHERE TODAY`S HEAVY RAIN BAND WILL BE. LATER TODAY THE MCV MOVES EAST OF AR...THEN TONIGHT THE UPPER RIDGE IS FORECAST TO BUILD A BIT MORE EAST...AND TAKE THE NEXT COMPLEX MORE NORTH TO EAST...WHICH WILL AFFECT MORE N TO NE AR. THIS HOLDS INTO TUESDAY WITH FORECAST POP MORE OVER N TO NE AR. STILL SOME CHANCE WILL BE OVER MUCH OF THE STATE...BUT SHOULD BE LOWER. TUESDAY NIGHT TO WEDNESDAY AND THURSDAY...CONVECTION IS ALSO EXPECTED TO BE MORE FOCUSED OVER NORTHERN AR WITH MODEL FORECAST SHORT WAVE ENERGY. A FLASH FLOOD WATCH WILL PROBABLY BE DROP LATER TUESDAY TO WEDNESDAY BUT MAY HAVE TO BE CONSIDERED IF MORE HEAVY CONVECTION IS ANTICIPATED. OTHERWISE TEMPERATURES WILL GRADUALLY WARM INTO MID WEEK AS THE UPPER RIDGE LOWERS RAIN CHANCES A BIT AND THE HEAT OVER TEXAS MOVES INTO AR. && .LONG TERM...FRIDAY THROUGH SUNDAY UPPER LEVEL HIGH PRESSURE WILL BE OVER ARKANSAS THROUGH THE LONG TERM PERIOD. ALSO...THE HIGH WILL STRENGTHEN NORTHWEST INTO THE NORTHERN ROCKIES. A COLD FRONT WILL MOVE INTO NORTH ARKANSAS FRIDAY AND STALL. THE FRONT SHOULD HANG AROUND NORTH ARKANSAS THROUGH THE WEEKEND. THIS WILL KEEP CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST WITH BEST CHANCES IN THE NORTH THROUGH THE PERIOD. THE HIGH PRESSURE MAY SHIFT WESTWARD SUNDAY AND PROVIDE MORE OF A NORTHWEST FLOW AND BETTER CHANCES OF PRECIPITATION. NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 86 72 91 73 / 80 30 30 20 CAMDEN AR 94 76 97 75 / 50 10 10 10 HARRISON AR 88 72 91 72 / 90 30 20 20 HOT SPRINGS AR 93 74 95 74 / 40 20 10 10 LITTLE ROCK AR 90 74 94 75 / 60 20 20 10 MONTICELLO AR 93 76 96 76 / 50 10 10 10 MOUNT IDA AR 94 74 96 74 / 40 10 10 10 MOUNTAIN HOME AR 87 71 90 72 / 90 30 30 20 NEWPORT AR 86 73 91 74 / 60 30 30 20 PINE BLUFF AR 91 75 95 75 / 50 20 20 10 RUSSELLVILLE AR 90 73 94 74 / 60 20 20 20 SEARCY AR 88 74 92 74 / 60 20 20 20 STUTTGART AR 90 75 94 75 / 60 20 20 10 && .LZK WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS EVENING FOR BAXTER-BOONE-CLEBURNE- FULTON-INDEPENDENCE-IZARD-JOHNSON-MARION-NEWTON-POPE-SEARCY- SHARP-STONE-VAN BUREN. && $$ SHORT TERM...59 / LONG TERM...51
AREA FORECAST DISCUSSION
NWS TUCSON AZ
207 PM MST MON AUG 5 2013 .SYNOPSIS...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL CONTINUE THROUGH THE EARLY PORTION OF THE WEEK...THEN A BIT DRIER WITH ISOLATED TO SCATTERED THUNDERSTORMS FROM THE MIDDLE OF THE WEEK INTO NEXT WEEKEND. && .DISCUSSION...VISIBLE IMAGERY SHOWS A DOUBLE VORTEX MCV FROM THE DECAYING COMPLEX LAST NIGHT AND EARLY THIS MORNING IS NOW NEAR SHOW LOW. MEANWHILE...ANOTHER MCV IS OVER WEST CENTRAL SONORA...RIGHT ALONG THE COAST. EXTENSIVE MID LEVEL CLOUDINESS ASSOCIATED WITH THIS SYSTEM EXTENDS NORTHWARD ACROSS NORTHWEST SONORA AND INTO SOUTH CENTRAL ARIZONA. MEANWHILE...MOSTLY CLEAR SKIES ARE EVIDENT ACROSS SOUTHEAST ARIZONA...MORE SPECIFICALLY OVER MUCH OF GREENLEE...GRAHAM AND COCHISE COUNTIES. IN ADDITION...CONVECTION HAS BEEN IGNITING OVER THE SIERRA MADRES OF NORTHWEST CHIHUAHUA. THIS BAND OF STORMS SHOULD CONTINUE TO LIFT TO THE NORTH WITH VARIOUS MODELS SUGGESTING THAT ACTIVITY WILL GET STARTED ALONG THE INTERNATIONAL BORDER THIS AFTERNOON. THAT SAID...WATER VAPOR IMAGERY SHOWS AN IMPULSE OVER SOUTHERN SONORA MEXICO AND MOVING NORTHWARD WHICH HAS BEEN PART OF THE IMPETUS FOR THE CURRENT DEVELOPMENT OVER THE SIERRA MADRES. MODELS PICK UP ON THIS FEATURE WITH THE MODELS SHOWING IT MOVING ACROSS NORTHERN SONORA MEXICO AND INTO SOUTHERN ARIZONA OVERNIGHT. IN ADDITION...THE HRRR AND THE U OF A WRF-NAM SUGGEST THAT WE SHOULD SEE LIGHT ACTIVITY THROUGH THE EARLY AFTERNOON...BUT CONVECTION WILL IGNITE EITHER SIDE OF THE INTERNATIONAL BORDER AND SPREAD NORTH DURING THE MID TO LATE AFTERNOON AND CONTINUE INTO THE EVENING HOURS. SHOULD EVEN SEE CONVECTION CONTINUE AFTER MIDNIGHT TONIGHT AS THE VORT MAX MOVES THROUGH THE AREA. ADJUSTED THE POP FORECAST FOR THE 00Z-06Z PERIOD TO INCREASE CHANCES ALONG THE INTERNATIONAL BORDER WEST OF NOGALES AND COVERING SOUTHERN PORTIONS OF THE TOHONO O`ODHAM NATION. AS THE SYSTEM FROM NORTHERN MEXICO MAKES ITS WAY NORTHWARD THROUGH THIS EVENING AND OVERNIGHT...AND EVENTUALLY INTO THE NORTHERN PART OF THE STATE BY LATE TUESDAY...THE FORCING FROM THIS SYSTEM SHOULD RESULT IN SCATTERED STORM DEVELOPMENT OVER MOST OF THE DESERT/VALLEY LOCATIONS AND SLIGHTLY BETTER CHANCES FOR THE HIGHER TERRAIN ON TUESDAY. BY WEDNESDAY THE PACIFIC STORM SYSTEM WILL BEGIN TO MOVE ALONG THE COASTAL AREAS OF NORTHERN CALIFORNIA BY LATE WEDNESDAY OR EARLY THURSDAY. THIS WILL RESULT IN WEST TO SOUTHWEST WINDS ALOFT AHEAD OF THIS SYSTEM PUSHING MOISTURE TO THE EAST. RAIN CHANCES WILL DECREASE FROM THE MIDDLE TO LATTER PART OF THE WEEK. AS THE PACIFIC LOW LIFTS INTO OREGON OVER THE WEEKEND...THE HIGH TO THE EAST WILL RETROGRADE A BIT FOR A WARMING TREND. HIGHS WILL GENERALLY BE AROUND 3 TO 5 DEGS BELOW NORMAL TUESDAY... THEN NEAR NORMAL FOR WEDNESDAY...AND SLIGHTLY ABOVE NORMAL FOR THURSDAY. THEREAFTER...HIGHS ABOUT 3 TO 5 DEGS ABOVE NORMAL. LOWS WILL BE AROUND 1 TO 3 DEGS ABOVE NORMAL FOR TUESDAY THROUGH FRIDAY MORNINGS...THEN ABOUT 4 TO 6 DEGS ABOVE NORMAL FOR SATURDAY THROUGH MONDAY. && .AVIATION...SCT-BKN CLOUDS AT 10-13K FT AGL...AND BKN-OVC CLOUDS AOA 20K FT AGL THRU 05/23Z. AFT 05/23Z...SCT CLOUDS AT 7-10K FT AGL WITH ISOLD SHRA/TSRA THROUGH 05/23Z...THEN SCT TSRA DEVELOPING AFT 05/23Z AND CONTINUING THRU 06/05Z...ESPECIALLY FROM KDUG TO KOLS AND AREAS FARTHER WEST. THESE STORMS WILL THEN MOVE NORTH LATER THIS EVENING WITH A POTENTIAL FOR ISOLD ACTIVITY PERSISTING OVERNIGHT. WIND GUSTS TO 45 KTS NEAR ANY TSRA...AS WELL AS LOCAL MVFR/IFR CIGS/VSBYS. OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS THRU 06/18Z. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...MOISTURE WILL REMAIN IN PLACE ACROSS THE REGION THROUGH THE FIRST PART OF THIS WEEK...RESULTING IN A CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST ARIZONA. SLIGHTLY DRIER AIR WILL MOVE IN FROM THE WEST DURING THE LATTER PART OF THE WEEK AND INTO THE WEEKEND FOR SLIGHTLY LESSER RAIN CHANCES. OUTSIDE OF GUSTY THUNDERSTORM OUTFLOWS...WINDS DURING THE PERIOD ARE EXPECTED TO BE LIGHT...GENERALLY LESS THAN 15 MPH AND DIURNALLY DRIVEN. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
352 PM MDT MON AUG 5 2013 .SHORT TERM...CURRENT ANALYSIS SHOWS SCATTERED STORMS OVER THE MOUNTAINS WITH A FEW JUST BEGINNING TO SPREAD EASTWARD ONTO THE HIGHER TERRAIN NEAR THE WYOMING BORDER. STILL SEE THE MAIN THREAT OF ANY SEVERE STORMS NORTHEAST OF A LINE FROM WELLINGTON TO FORT MORGAN AND LIMON WHERE BEST COMBINATION OF DAYTIME HEATING AND DEEPEST MOISTURE/INSTABILITY EXISTS WITH CAPES OF 1000-2000 J/KG. FARTHER WEST INCLUDING THE I-25 URBAN CORRIDOR...TEMPERATURES WERE FINALLY BEGINNING TO WARM POST SURGE...BUT STILL STRUGGLING TO REACH CONVECTIVE TEMPS. AS A RESULT...NOT CERTAIN WE WILL SEE STORMS BUT STILL HAVE A COUPLE HOURS TO WARM AND HELP BREAK THE CAP. IN ANY CASE...DEWPOINTS WERE BEGINING TO MIX SO THREAT OF ANY STRONGER STORMS CLOSER TO THE FOOTHILLS LOOKS LOW BARRING ANY STRONGER OUTFLOWS. SHOWERS AND STORMS ARE EXPECTED TO DECREASE FROM WEST TO EAST THROUGH THE COURSE OF THE EVENING AS UPPER LEVEL DIVERGENCE ASSOCIATED WITH RIGHT REAR ENTRANCE REGION OF UPPER JET CONTINUES TO PUSH EAST. FOR TUESDAY...THE PLAINS FORECAST WILL LIKELY HINGE ON THE POSSIBILITY OF ANOTHER SURGE OF SLIGHTLY COOLER BUT MORE MOIST AIR. THIS WOULD BE FROM YET ANOTHER STORM COMPLEX LIKELY TO ORIGINATE IN THE NORTHERN PLAINS AND ROLL SOUTHEAST THROUGH NEBRASKA OVERNIGHT. AS A RESULT...HAVE COOLED OFF THE NORTHEAST CORNER A BIT...RAISED DEWPOINTS...AND WILL KEEP A LITTLE BETTER CHANCE OF STORMS ON THE PLAINS LATE IN THE AFTERNOON. .LONG TERM...CHANCE OF STORMS TO PERSIST ACROSS THE MOUNTAINS THROUGH THE EVENING WITH SOME INCREASE IN SUBTROPICAL MOISTURE. ACROSS PLAINS...AIRMASS LOOKING MORE MOIST WITH AN INCREASE IN LOW LEVEL MOISTURE BUT A BIT MORE STABLE BEHIND AFTERNOON`S COLD FRONT..NOW LOOKING LIKE THE BEST CHANCE FOR STORMS TO BE ALONG FOOTHILLS AND PALMER DIVIDE. AFTER MIDNIGHT...THERE IS SOME INCREASE IN MID LEVEL QG ASCENT AS UPPER TROUGH MOVES INTO THE GREAT BASIN. THIS SHOULD ALLOW FOR AT LEAST A CHANCE OF STORMS OVER THE MOUNTAINS WITH PERHAPS SOME INCREASE ACROSS THE PLAINS. WITH THE INCREASE IN LOW LEVEL MOISTURE...SOME STORMS COULD PRODUCE BRIEF MODERATE TO HEAVY RAINFALL. ON WEDNESDAY...UPPER TROUGH TO SLOWLY MOVE ACROSS COLORADO WITH AN INCREASE IN MID LEVEL QG ASCENT. CROSS SECTIONS STILL INDICATING DECENT MOISTURE ACROSS AREA. ENOUGH SHEAR AND MID LEVEL ASCENT WILL HELP TO INCREASE STORM CHANCES ACROSS MOUNTAINS IN AND NEAR FOOTHILLS BY THE AFTERNOON AND WILL INCREASE POPS TO THE LIKELY CATEGORY. COOLER AIRMASS TO LIMIT THE INTENSITY OF THE STORMS...STILL THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH AN INCREASING THREAT OF FLOODING ALONG THE FOOTHILLS. HIGHS TO COOL INTO THE MIDDLE 70S ACROSS THE PLAINS. STORMS TO DECREASE DURING THE EVENING AS TROUGH AXIS SHIFTS ACROSS THE EASTERN PLAINS...ENDING OVER MUCH OF THE AREA AFTER MIDNIGHT. ON THURSDAY....UPPER TROUGH TO BE EAST OF THE AREA WITH WEAK SUBSIDENCE SPREADING INTO NORTHWEST COLORADO. CROSS SECTIONS STILL SHOW GOOD MOISTURE ACROSS THE AREA...MAINLY ACROSS THE MOUNTAINS. WILL MAINTAIN THE CHANCE OF STORMS FOR THE HIGH COUNTRY AND A SLIGHT CHANCE OVER THE PLAINS. TEMPERATURES TO WARM SLIGHTLY...INTO THE LOWER AND MIDDLE 80S ACROSS THE PLAINS. ON FRIDAY...SOUTHWEST FLOW ALOFT TO PREVAIL WITH UPPER HIGH CENTERED OVER EASTERN TEXAS. FLOW TO BRING AN INCREASE IN SUBTROPICAL MOISTURE ACROSS THE AREA... MAINLY ACROSS THE MOUNTAINS. BEST CHANCE FOR STORMS TO BE OVER THE HIGH COUNTRY DURING THE AFTERNOON AND EVENING. FOR THE LATER DAYS SATURDAY THROUGH SUNDAY: SOUTHWEST FLOW ALOFT TO PREVAIL WITH SUBTROPICAL MOISTURE STILL AFFECTING THE AREA. LATEST MODELS KEEP SURFACE FRONT EAST OF THE AREA SATURDAY...SO CHANCES FOR STORMS ACROSS PLAINS NOT EXPECTED TO INCREASE. WILL MAINTAIN THE CHANCE FOR THUNDERSTORMS ACROSS THE MOUNTAINS DURING THE AFTERNOON AND EVENING...WITH A SLIGHT CHANCE OVER THE PLAINS. TEMPERATURES TO GRADUALLY WARM INTO THE MID AND UPPER 80S ACROSS THE PLAINS. && .AVIATION...THREAT OF AT LEAST SOME HIGH BASED CONVECTION IS HIGH ENOUGH TO WARRANT POSSIBILITY OF GUSTY WINDS TIL AROUND 02Z-03Z. MESOSCALE HRRR MODELS SUPPORTS THIS SCENARIO AS WELL. WILL ADDRESS THUNDER THREAT AS NEEDED...BUT ONLY A CHANCE AT THIS POINT. OTHERWISE WINDS WILL EVENTUALLY TRANSITION TO DRAINAGE WINDS OVERNIGHT...AND THEN BACK TO NORTH/NORTHEASTERLIES BY 16Z-18Z TUESDAY. && .HYDROLOGY...LOOKS LIKE THE FOOTHILL BURN SCARS ARE ON THE EDGE OF DEEPER MOISTURE AND HEAVIER RAIN THREAT. STRONGER STORMS ON THE PLAINS WILL BE CAPABLE OF PRODUCING 1 TO 1.5 INCHES IN 40 MINUTES...WHILE STRONGER FOOTHILL STORMS COULD PRODUCE 0.5 TO 0.75 INCH. SIMILAR SITUATION EXPECTED TUESDAY. ON WEDNESDAY...PRECIPITABLE WATER VALUES INCREASE AND MORE EFFICIENT RAINERS ARE ANTICIPATED. STORM COVERAGE SHOULD ALSO BE CONSIDERABLY HIGHER RESULTING IN A HIGHER THREAT OF FLOODING. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BARJENBRUCH LONG TERM....D-L AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION...CORRECTED
NWS PUEBLO CO
323 PM MDT MON AUG 5 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 244 PM MDT MON AUG 5 2013 ACTIVE DAY FOR THE WESTERN SLOPES TODAY AS THUNDERSTORMS FIRED UP EARLIER THAN PAST COUPLE DAYS WITHIN THE MONSOON PLUME. THIS IS OUT AHEAD OF LEADING DISTURBANCE MOVING THROUGH SOUTHERN AZ. MEANWHILE...ANOTHER DISTURBANCE IS EXITING EASTERN CO TO THE EAST. DEW POINTS HAVE BEEN FALLING OFF ACROSS THE SE MTS/I-25 CORRIDOR AS PROGGED BY MODELS WITH 40 DEW POINTS AND EVEN SOME UPPER 30S. EVEN OUT TOWARDS LA JUNTA AND LAMAR...DEW POINTS HAVE BEEN FALLING INTO THE LOWER 50S AS WINDS HAVE SHIFTED OUT OF THE SOUTH AND EVEN SOUTHWEST AS THE SFC LOW HAS BEEN KICKING EASTWARD. FOR THE REMAINDER OF THIS EVENING...SCATTERED THUNDERSTORMS EXPECTED ACROSS THE MOUNTAINS...WITH HRRR SUGGESTING THUNDERSTORMS WILL SPREAD INTO THE ADJACENT PLAINS DURING THE LATE AFTERNOON/EARLY EVENING. NOT AS MUCH CAPE TODAY...SO NOT EXPECTING ANY STRONG STORMS ALONG THE I-25 CORRIDOR. WRF WAS HITTING WALDO BURN SCAR BETWEEN 3-5 PM...WHILE EACH SUCCESSIVE RUN OF THE HRRR HAS BEN DELAYING THIS POTENTIAL UNTIL A NORTHERLY SURGE AIDED BY CONVECTION ACROSS NE CO DROPS INTO THE PIKES PEAK REGION JUST AS WEAK FORCING ENHANCING WRN CO CONVECTION WORKS ITS WAY EASTWARD ACROSS THE SE MTS. THIS PUTS TIME FRAME FOR WALDO TO GET HIT BETWEEN 6PM-8PM WHICH MAY BE A LITTLE DELAYED FROM BEST SFC BASED HEATING TO REALIZE STRONG CONVECTION AND HIGH RAINFALL RATES. BUT THIS WILL HAVE TO BE MONITORED CLOSELY. OTHER AREA OF CONCERN BESIDES WILL BE OUT WEST ACROSS THE PAPOOSE AND WEST FORK BURN SCARS WHERE THEY WILL BE UNDER THE GUN FROM STORMS AND HEAVY RAINFALL/POTENTIAL FLASH FLOODING UNTIL 8 PM. MEANWHILE...FAR SOUTHEAST PLAINS WILL HAVE TO BE WATCHED CLOSELY AS CONVECTION ACROSS NW KS SENDS A BOUNDARY SOUTHWESTWARD INTO SE CO...INCREASING SFC DEW POINTS. COULD SEE SOME THUNDERSTORMS DEVELOP ALONG THE LEADING EDGE OF THIS OUTFLOW ACROSS KIOWA...PROWERS AND BACA COUNTIES WITH POTENTIAL FOR A STRONG STORM OR TWO. MAIN THREAT WINDOW WILL BE DURING THE EVENING...WITH POTENTIAL FOR NEAR SEVERE HAIL AND WIND. BEST SEVERE THREAT THOUGH APPEARS TO BE JUST NORTH AND EAST OF THE AREA. TONIGHT...LOTS OF MID/HIGH CLOUDINESS WILL KEEP TEMPERATURES ON THE WARM SIDE...WITH POPS DIMINISHING FOR MOST AREAS BY MIDNIGHT. CAN`T RULE OUT SOME ISOLATED SHOWERS AND THUNDERSTORMS OUT WEST WITHIN THE MONSOON PLUME. ON TUESDAY...PERHAPS A BIT MORE ACTIVE OUT WEST AS SHORTWAVES EMBEDDED IN MONSOON PLUME WORK THEIR WAY NORTHWARD THROUGH AZ INTO SRN UT/FOUR CORNERS REGION TOWARDS 00Z. CONTEMPLATED GOING WITH A FLASH FLOOD WATCH FOR THE WEST FORK AND PAPOOSE BURN SCARS TOMORROW...BUT SFC DEW POINTS DON`T APPEAR TO MOISTEN ALL THAT MUCH...AND MODEL QPFS OFF THE LARGER SCALE MODELS ARE NOT ALL THAT MUCH HIGHER. STILL THERE IS SOME INCREASE IN PRECIP WATERS OUT THAT WAY...SO WILL HAVE TO MONITOR THIS POTENTIAL. WILL LET LATER SHIFTS GET A LOOK AT THE HIGH RES SHORT RANGE MODELS AS THEY START TO RESOLVE THAT PERIOD. OTHERWISE...FOR THE EASTERN AREAS LOOKS LIKE MORE OF THE SAME. ANOTHER DAY OF LOWER SFC DEW POINTS ACROSS THE PLAINS WHICH KEEPS LCLS ON THE HIGH SIDE. STILL ENOUGH MOISTURE IN THE MONSOON PLUME FOR SOME LOCALLY HEAVY RAIN WITH THE STRONGER STORMS...BUT FOR NOW THIS THREAT LOOKS TOO LOCALIZED TO WARRANT ANY FLASH FLOOD WATCHES FOR THE WALDO OR BLACK FOREST. THIS COULD CHANGE INTO THE EVENING HOURS AS MODELS DROP A FRONT REINFORCED BY THUNDERSTORM OUTFLOWS INTO THE AREA FROM NE CO. -KT .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 244 PM MDT MON AUG 5 2013 ...HEAVY RAIN EXPECTED ON WEDNESDAY... HIGH PRESSURE OVER TEXAS AND AN AREA OF LOW PRESSURE OFF THE NORTHERN CALIFORNIA COAST WILL FORCE SOUTHERLY MONSOON ENERGY ACROSS COLORADO THROUGH THURSDAY. THIS WILL SET THE STAGE FOR WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY TUESDAY NIGHT THROUGH THURSDAY AFTERNOON. EXPECT ACTIVE SHOWER AND THUNDERSTORM ACTIVITY TUESDAY EVENING OVER THE MOUNTAINS AND SPREADING INTO THE PLAINS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE DURING THIS TIME PERIOD. MODELS INDICATING A SMALL LULL AROUND MIDNIGHT BEFORE ACTIVITY INCREASES AGAIN HEADING INTO WEDNESDAY MORNING. HOW QUICKLY THINGS PICK LATE TUESDAY NIGHT/WEDNESDAY MORNING WILL DEPEND ON HOW FAST A FRONT MOVES SOUTH ACROSS THE AREA...AND A STRONG SHORTWAVE EJECTS NORTHEAST OUT OF THE DESERT SOUTHWEST. FRONTAL TIMING LOOKS TO IMPACT THE AREA BY WEDNESDAY MORNING WITH A VERY MOIST AIR MASS MOVING INTO THE PLAINS BEHIND THE FRONT. IN ADDITION...LOW LEVEL FLOW IS FORECAST TO TURN EASTERLY WITH GOOD UPSLOPE FLOW ACROSS THE PLAINS. ALL OF THESE LOW LEVEL FEATURES WILL COMBINE WITH A VERY STRONG SHORTWAVE TROUGH ACROSS COLORADO TO PRODUCE WIDESPREAD MODERATE TO HEAVY RAINFALL ACROSS THE AREA. IN ADDITION...COLDER AIR ALOFT WILL MOVE INTO THE AREA WHICH WILL LIKELY INCREASE LAPSE RATES AND INSTABILITY ACROSS COLORADO. THE AREA OF GREATEST CONCERN WILL BE THE EASTERN MOUNTAINS AND I-25 CORRIDOR. MODELS ARE INDICATING WELL OVER AN INCH OF PRECIPITATION WILL BE POSSIBLE...ESPECIALLY IF WE CAN GET ENHANCEMENT FROM CONVECTIVE UPDRAFTS. THE ONE CAVEAT MAY BE CLOUD COVER ACROSS THE PLAINS WHICH WOULD LIMIT INSTABILITY AND CONVECTIVE ENHANCEMENT. THIS WILL NEED TO BE WATCHED. FLASH FLOODING WILL BE OF GREAT CONCERN...ESPECIALLY FOR AREA BURN SCARS. EXTREME CAUTION IS ADVISED AND FOLKS SHOULD REMAIN COGNIZANT OF THE WEATHER AROUND THEM. THE UPPER SYSTEM WILL BE SLOW TO MOVE OUT...WITH THE MODERATE TO HEAVY RAINFALL SLOWLY MOVING EAST ACROSS THE PLAINS WEDNESDAY NIGHT. THURSDAY...MOISTURE WILL BE IN PLACE AND DEPARTING UPPER LEVEL ENERGY WILL LIKELY LEAD TO SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE MOUNTAINS THURSDAY AFTERNOON. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE...AND FLASH FLOODING WILL BE POSSIBLE OVER AREA BURN SCARS. IF TRENDS HAVE ANYTHING TO SAY ABOUT IT...THE DAY AFTER EXPECTED WIDESPREAD HEAVY RAINFALL EVENTS SEEM TO BE PRIMED FOR HEAVIER RAINFALL OUT OF THUNDERSTORMS THAN MODELS SEEM TO INDICATE. THE PATTERN BEGINS TO SHIFT FRIDAY INTO EARLY NEXT WEEK. THE LOW OFF NORTHERN CALIFORNIA WILL DRIFT NORTHWARD HAS HIGH PRESSURE OVER TEXAS BUILDS NORTH ACROSS COLORADO. THE MAIN MONSOONAL TAP SHIFTS WESTWARD INTO THE GREAT BASIN. MODELS ARE INDICATING A DOWNWARD TREND IN CONVECTIVE ACTIVITY THROUGH THE WEEKEND WITH SHOWER AND THUNDERSTORM ACTIVITY REMAINING CONFINED TO MOUNTAIN AREAS. MOZLEY && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 244 PM MDT MON AUG 5 2013 THUNDERSTORMS WILL DRIFT EASTWARD INTO THE ADJACENT PLAINS THIS EVENING AND WILL BE MOST LIKELY TO AFFECT KALS AND KCOS. WILL CARRY VCTS IN BOTH THESE TERMINALS THROUGH 01Z...WITH POTENTIAL FOR GUSTY OUTFLOW WINDS 25-30 KTS. KPUB WILL HAVE THE LOWEST CHANCE. THUNDERSTORMS WILL BRING BRIEF MVFR CIGS/VIS. THUNDERSTORMS WILL DIMINISH AFTER SUNSET FOR THE TERMINALS WITH SOME MID/HIGH DECK OF CLOUDINESS PERSISTING OVERNIGHT WHICH SHOULD PREVENT FORMATION OF ANY FOG/LOW STRATUS AT TERMINALS OVERNIGHT. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KT LONG TERM...MOZLEY AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
305 PM MDT MON AUG 5 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 244 PM MDT MON AUG 5 2013 ACTIVE DAY FOR THE WESTERN SLOPES TODAY AS THUNDERSTORMS FIRED UP EARLIER THAN PAST COUPLE DAYS WITHIN THE MONSOON PLUME. THIS IS OUT AHEAD OF LEADING DISTURBANCE MOVING THROUGH SOUTHERN AZ. MEANWHILE...ANOTHER DISTURBANCE IS EXITING EASTERN CO TO THE EAST. DEW POINTS HAVE BEEN FALLING OFF ACROSS THE SE MTS/I-25 CORRIDOR AS PROGGED BY MODELS WITH 40 DEW POINTS AND EVEN SOME UPPER 30S. EVEN OUT TOWARDS LA JUNTA AND LAMAR...DEW POINTS HAVE BEEN FALLING INTO THE LOWER 50S AS WINDS HAVE SHIFTED OUT OF THE SOUTH AND EVEN SOUTHWEST AS THE SFC LOW HAS BEEN KICKING EASTWARD. FOR THE REMAINDER OF THIS EVENING...SCATTERED THUNDERSTORMS EXPECTED ACROSS THE MOUNTAINS...WITH HRRR SUGGESTING THUNDERSTORMS WILL SPREAD INTO THE ADJACENT PLAINS DURING THE LATE AFTERNOON/EARLY EVENING. NOT AS MUCH CAPE TODAY...SO NOT EXPECTING ANY STRONG STORMS ALONG THE I-25 CORRIDOR. WRF WAS HITTING WALDO BURN SCAR BETWEEN 3-5 PM...WHILE EACH SUCCESSIVE RUN OF THE HRRR HAS BEN DELAYING THIS POTENTIAL UNTIL A NORTHERLY SURGE AIDED BY CONVECTION ACROSS NE CO DROPS INTO THE PIKES PEAK REGION JUST AS WEAK FORCING ENHANCING WRN CO CONVECTION WORKS ITS WAY EASTWARD ACROSS THE SE MTS. THIS PUTS TIME FRAME FOR WALDO TO GET HIT BETWEEN 6PM-8PM WHICH MAY BE A LITTLE DELAYED FROM BEST SFC BASED HEATING TO REALIZE STRONG CONVECTION AND HIGH RAINFALL RATES. BUT THIS WILL HAVE TO BE MONITORED CLOSELY. OTHER AREA OF CONCERN BESIDES WILL BE OUT WEST ACROSS THE PAPOOSE AND WEST FORK BURN SCARS WHERE THEY WILL BE UNDER THE GUN FROM STORMS AND HEAVY RAINFALL/POTENTIAL FLASH FLOODING UNTIL 8 PM. MEANWHILE...FAR SOUTHEAST PLAINS WILL HAVE TO BE WATCHED CLOSELY AS CONVECTION ACROSS NW KS SENDS A BOUNDARY SOUTHWESTWARD INTO SE CO...INCREASING SFC DEW POINTS. COULD SEE SOME THUNDERSTORMS DEVELOP ALONG THE LEADING EDGE OF THIS OUTFLOW ACROSS KIOWA...PROWERS AND BACA COUNTIES WITH POTENTIAL FOR A STRONG STORM OR TWO. MAIN THREAT WINDOW WILL BE DURING THE EVENING...WITH POTENTIAL FOR NEAR SEVERE HAIL AND WIND. BEST SEVERE THREAT THOUGH APPEARS TO BE JUST NORTH AND EAST OF THE AREA. TONIGHT...LOTS OF MID/HIGH CLOUDINESS WILL KEEP TEMPERATURES ON THE WARM SIDE...WITH POPS DIMINISHING FOR MOST AREAS BY MIDNIGHT. CAN`T RULE OUT SOME ISOLATED SHOWERS AND THUNDERSTORMS OUT WEST WITHIN THE MONSOON PLUME. ON TUESDAY...PERHAPS A BIT MORE ACTIVE OUT WEST AS SHORTWAVES EMBEDDED IN MONSOON PLUME WORK THEIR WAY NORTHWARD THROUGH AZ INTO SRN UT/FOUR CORNERS REGION TOWARDS 00Z. CONTEMPLATED GOING WITH A FLASH FLOOD WATCH FOR THE WEST FORK AND PAPOOSE BURN SCARS TOMORROW...BUT SFC DEW POINTS DON`T APPEAR TO MOISTEN ALL THAT MUCH...AND MODEL QPFS OFF THE LARGER SCALE MODELS ARE NOT ALL THAT MUCH HIGHER. STILL THERE IS SOME INCREASE IN PRECIP WATERS OUT THAT WAY...SO WILL HAVE TO MONITOR THIS POTENTIAL. WILL LET LATER SHIFTS GET A LOOK AT THE HIGH RES SHORT RANGE MODELS AS THEY START TO RESOLVE THAT PERIOD. OTHERWISE...FOR THE EASTERN AREAS LOOKS LIKE MORE OF THE SAME. ANOTHER DAY OF LOWER SFC DEW POINTS ACROSS THE PLAINS WHICH KEEPS LCLS ON THE HIGH SIDE. STILL ENOUGH MOISTURE IN THE MONSOON PLUME FOR SOME LOCALLY HEAVY RAIN WITH THE STRONGER STORMS...BUT FOR NOW THIS THREAT LOOKS TOO LOCALIZED TO WARRANT ANY FLASH FLOOD WATCHES FOR THE WALDO OR BLACK FOREST. THIS COULD CHANGE INTO THE EVENING HOURS AS MODELS DROP A FRONT REINFORCED BY THUNDERSTORM OUTFLOWS INTO THE AREA FROM NE CO. -KT .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 244 PM MDT MON AUG 5 2013 ...HEAVY RAIN EXPECTED ON WEDNESDAY... HIGH PRESSURE OVER TEXAS AND AN AREA OF LOW PRESSURE OFF THE NORTHERN CALIFORNIA COAST WILL FORCE SOUTHERLY MONSOON ENERGY ACROSS COLORADO THROUGH THURSDAY. THIS WILL SET THE STAGE FOR WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY TUESDAY NIGHT THROUGH THURSDAY AFTERNOON. EXPECT ACTIVE SHOWER AND THUNDERSTORM ACTIVITY TUESDAY EVENING OVER THE MOUNTAINS AND SPREADING INTO THE PLAINS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE DURING THIS TIME PERIOD. MODELS INDICATING A SMALL LULL AROUND MIDNIGHT BEFORE ACTIVITY INCREASES AGAIN HEADING INTO WEDNESDAY MORNING. HOW QUICKLY THINGS PICK LATE TUESDAY NIGHT/WEDNESDAY MORNING WILL DEPEND ON HOW FAST A FRONT MOVES SOUTH ACROSS THE AREA...AND A STRONG SHORTWAVE EJECTS NORTHEAST OUT OF THE DESERT SOUTHWEST. FRONTAL TIMING LOOKS TO IMPACT THE AREA BY WEDNESDAY MORNING WITH A VERY MOIST AIR MASS MOVING INTO THE PLAINS BEHIND THE FRONT. IN ADDITION...LOW LEVEL FLOW IS FORECAST TO TURN EASTERLY WITH GOOD UPSLOPE FLOW ACROSS THE PLAINS. ALL OF THESE LOW LEVEL FEATURES WILL COMBINE WITH A VERY STRONG SHORTWAVE TROUGH ACROSS COLORADO TO PRODUCE WIDESPREAD MODERATE TO HEAVY RAINFALL ACROSS THE AREA. IN ADDITION...COLDER AIR ALOFT WILL MOVE INTO THE AREA WHICH WILL LIKELY INCREASE LAPSE RATES AND INSTABILITY ACROSS COLORADO. THE AREA OF GREATEST CONCERN WILL BE THE EASTERN MOUNTAINS AND I-25 CORRIDOR. MODELS ARE INDICATING WELL OVER AN INCH OF PRECIPITATION WILL BE POSSIBLE...ESPECIALLY IF WE CAN GET ENHANCEMENT FROM CONVECTIVE UPDRAFTS. THE ONE CAVEAT MAY BE CLOUD COVER ACROSS THE PLAINS WHICH WOULD LIMIT INSTABILITY AND CONVECTIVE ENHANCEMENT. THIS WILL NEED TO BE WATCHED. FLASH FLOODING WILL BE OF GREAT CONCERN...ESPECIALLY FOR AREA BURN SCARS. EXTREME CAUTION IS ADVISED AND FOLKS SHOULD REMAIN COGNOSCENTE OF THE WEATHER AROUND THEM. THE UPPER SYSTEM WILL BE SLOW TO MOVE OUT...WITH THE MODERATE TO HEAVY RAINFALL SLOWLY MOVING EAST ACROSS THE PLAINS WEDNESDAY NIGHT. THURSDAY...MOISTURE WILL BE IN PLACE AND DEPARTING UPPER LEVEL ENERGY WILL LIKELY LEAD TO SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE MOUNTAINS THURSDAY AFTERNOON. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE...AND FLASH FLOODING WILL BE POSSIBLE OVER AREA BURN SCARS. IF TRENDS HAVE ANYTHING TO SAY ABOUT IT...THE DAY AFTER EXPECTED WIDESPREAD HEAVY RAINFALL EVENTS SEEM TO BE PRIMED FOR HEAVIER RAINFALL OUT OF THUNDERSTORMS THAN MODELS SEEM TO INDICATE. THE PATTERN BEGINS TO SHIFT FRIDAY INTO EARLY NEXT WEEK. THE LOW OFF NORTHERN CALIFORNIA WILL DRIFT NORTHWARD HAS HIGH PRESSURE OVER TEXAS BUILDS NORTH ACROSS COLORADO. THE MAIN MONSOONAL TAP SHIFTS WESTWARD INTO THE GREAT BASIN. MODELS ARE INDICATING A DOWNWARD TREND IN CONVECTIVE ACTIVITY THROUGH THE WEEKEND WITH SHOWER AND THUNDERSTORM ACTIVITY REMAINING CONFINED TO MOUNTAIN AREAS. MOZLEY && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 244 PM MDT MON AUG 5 2013 THUNDERSTORMS WILL DRIFT EASTWARD INTO THE ADJACENT PLAINS THIS EVENING AND WILL BE MOST LIKELY TO AFFECT KALS AND KCOS. WILL CARRY VCTS IN BOTH THESE TERMINALS THROUGH 01Z...WITH POTENTIAL FOR GUSTY OUTFLOW WINDS 25-30 KTS. KPUB WILL HAVE THE LOWEST CHANCE. THUNDERSTORMS WILL BRING BRIEF MVFR CIGS/VIS. THUNDERSTORMS WILL DIMINISH AFTER SUNSET FOR THE TERMINALS WITH SOME MID/HIGH DECK OF CLOUDINESS PERSISTING OVERNIGHT WHICH SHOULD PREVENT FORMATION OF ANY FOG/LOW STRATUS AT TERMINALS OVERNIGHT. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KT LONG TERM...MOZLEY AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1102 AM MDT MON AUG 5 2013 .UPDATE... ISSUED AT 703 AM MDT MON AUG 5 2013 UPDATED GRIDS/ZONES FOR SLIGHTLY LESS SKY COVERAGE OVER PORTIONS OF THE PLAINS...AND TO DROP LOW POPS FOR THE MTS FOR THE EARLY MON MORNING PERIOD. HIGH CLOUDS CONTINUE TO STREAM UP FROM THE SOUTH...SO STILL THINK WE WILL SEE MORE CLOUDS THAN SUN TODAY. MOST RECENT HRRR IS SHOWING FAIRLY STRONG QPF MOVING OVER THE WALDO AND BLACK FOREST AREAS AFTER 23Z TODAY...WHILE OTHER MODELS ARE A BIT MORE SPARSE. WILL HAVE TO WATCH CONVECTIVE TRENDS CLOSELY THIS AFTERNOON GIVEN THE RECENT HEAVY RAINS. ROSE && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM MDT MON AUG 5 2013 ...A BIT QUIETER TODAY...STILL SOME FLOODING CONCERNS... CURRENTLY...JUST A FEW SHOWERS LINGERING NR THE KS AND OK BORDERS. KALS FINALLY DRYING OUT AFTER A COUPLE HOURS OF SOME FAIRLY GOOD RAINFALL...NEARLY HALF AN INCH...MOST OF WHICH WAS INVISIBLE TO RADAR DUE TO BLOCKAGE AND DISTANCE FROM THE WSR NETWORK. WILL PROBABLY SEE SOME LOW CLOUDS IN THE VALLEY THIS MORN. OTHERWISE...JUST SOME LOW CLOUDS AND A BIT OF FG POSSIBLE OVER THE FAR SERN PLAINS...ESPECIALLY KIOWA COUNTY. MAIN CONCERN TODAY WILL BE AN UPPER LEVEL DISTURBANCE THAT IS EMBEDDED UNDER THE RIDGE...WHICH CAN BE SEEN CURRENTLY KICKING OFF CONVECTION OVR NM. THIS WILL PROPAGATE THRU WRN CO THIS MORN. MAIN LIFT AND FOCUS FOR CONVECTION WILL BE LATER TODAY OVER KS...SO BELIEVE THAT THE BIGGEST IMPACT FROM THE DISTURBANCE WILL BE MOSTLY E OF OUR CWA. HOWEVER...WILL STILL SEE SCT STORMS DEVELOP EARLY TODAY OVER THE MTS...SPREADING TO THE I-25 CORRIDOR LATE IN THE AFTERNOON. SO...WILL STILL HAVE TO KEEP A CLOSE EYE OUT ON THE BURN SCARS EVEN THOUGH THE INTENSITY AND COVERAGE OF STORMS LOOKS A BIT LESS. FOR THE FAR ERN PLAINS...NR THE KS BORDER...THERE COULD BE MORE VIGOROUS CONVECTION...INCLUDING THE POTENTIAL FOR A STRONG STORM OR TWO...BUT BELIEVE THAT MOST OF THE HEAVY RAIN IMPACT WILL STAY FAR ENOUGH E TO PRESENT A SMALLER RISK FOR THE RIVERS. HAVE ALREADY ISSUED A COUPLE FLOOD WARNINGS FOR THE ARKANSAS AND PURGATOIRE...BUT THESE SPOTS SHOULD CREST AND BEGIN TO RECEDE LATER THIS MORNING. EXTENSIVE MID AND HIGH CLOUDS WILL CONTINUE TO LIMIT TEMPS TODAY...BUT WITH THE RIDGE BUILDING A BIT IT SHOULD BE A COUPLE DEGREES WARMER FOR MOST SPOTS THIS AFTERNOON. HIGH CLOUDS WILL THICKEN UP A BIT OVERNIGHT ESPECIALLY FOR THE NRN AND WRN PORTIONS OF THE CWA...LEADING TO ANOTHER MILD NIGHT. ROSE .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 355 AM MDT MON AUG 5 2013 ...WEDNESDAY COULD BE A RATHER WET AND STORMY DAY... NOT MUCH OVERALL CHANGE IN THE GUIDANCE. AS HAS BEEN STATED OVER THE LAST SEVERAL DAYS...THE MONSOON PLUME WILL REMAIN IN PLACE OVER THE FCST AREA THROUGH THIS FCST PERIOD...AND THIS PATTER N WILL KEEP THE REGION RATHER WET WITH SEASONABLE TEMPERATURES. THE MAIN DAY OF CONCERN APPEARS TO BE WEDNESDAY. NEARLY ALL SIMULATIONS ARE SHOWING THIS DAY IS LIKELY GOING TO BE WET...AND WE WILL LIKELY SEE OUR BEST CHANCE OF HEAVY RAINS OVER THE REGION. QUITE A FEW AREAS HAVE HAD DECENT RAINFALL IN THE LAST WEEK OR SO...SO FLASH FLOODING CONCERNS ARE GOING TO BE MORE WIDESPREAD WITH THIS EVENT (JUST NOT THE BURN SCARS). SIMULATIONS CONTINUE TO INDICATE SEVERAL FEATURES WILL COME INTO PLAY TO BRING THE THREAT OF HEAVY RAIN WEDNESDAY. FIRST...A COOL FRONT WILL MOVE IN TUESDAY NIGHT...BRINGING ANOTHER SURGE OF LLVL MOISTURE INTO THE REGION. THE UPPER LEVEL MONSOON PLUME WILL CONTINUE OVER THE REGION ADDING TO THE MOISTURE ALOFT. ADDITIONALLY...A WELL DEFINED DISTURBANCE WILL MOVE ACROSS THE REGION DURING THE DAY WEDNESDAY...AND THIS FEATURE WILL CREATE FAVORABLE DIFFLUENCE ALOFT TO ACCENTUATE THE UPWARD VERTICAL VELOCITY FIELDS OVER THE REGION. ALL THESE FEATURES COMING TOGETHER SHOULD ALLOW FOR HEAVY CONVECTIVE PRECIP WED. THE ONLY CONCERN I SEE FOR WED IS THAT CAPE MAY BE LIMITED AS IT MAY BE QUITE CLOUDY AND COOL...AND WITH LIMITED INSOLATION...CAPE VALUES MAY NOT GET TOO HIGH. IF WE DO SEE SOME SUN THEN THE THREAT OF HEAVIER RAIN WILL INCREASE. THERE IS ALSO A CHANCE THE CONVECTION MAY BE SEVERE ON THIS DAY (ESPECIALLY IF WE CAN GET SOME DECENT CAPE) AS SHEAR WILL BE MARGINAL FOR ROTATING STORMS. WITH THE LIKELY LOW LCLS...A FEW WEAK SUPERCELL TORNADOES WILL BE POSSIBLE. WRT TO THE NDFD GRIDS...I HAVE LIKELY POPS OVER THE MTNS WED WITH HIGH SCTD POPS ON THE PLAINS. I MENTIONED HEAVY RAIN (R+) IN THE WEATHER GRIDS. IT IS TOO EARLY TO MENTION SVR IN THE NDFD. IN THE MEANTIME...TUESDAY WE WILL SEE SCATTERED STORMS OVER THE MTNS WITH SCTD ACTIVITY MOVING ONTO THE PLAINS LATE IN THE DAY. TUESDAY NIGHT THE COOL FRONT WILL MOVE DOWN...AND I CANNOT RULE OUT SOME LOCALLY HEAVY RAIN THIS EVENING/NIGHT AS AN MCS MAY FORM ON THE SE PLAINS. WEDNESDAY WILL BE BUSY AS ALLUDED TO ABOVE. THURSDAY INTO THE WEEKEND CONTINUES TO LOOK BUSY. UPSLOPE WILL CONTINUE IN THE LLVLS AND MSTR WILL CONTINUE ALOFT WITH THE PERSISTENT SW MONSOON FLOW. NO WELL DEFINED SHORT WAVES ARE EXPECTED...BUT THERE WILL BE ENOUGH FORCING/INSTABILITY TO CONTINUE THE THREAT OF AFTERNOON AND EVENING SHOWER AND STORMS OVER THE ENTIRE REGION. SOME OF THE RAIN WILL BE LOCALLY HEAVY. /HODANISH && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1035 AM MDT MON AUG 5 2013 SCATTERED -TSRA WILL DEVELOP OVER THE MOUNTAINS DURING THE EARLY AFTERNOON AND SPREAD INTO THE VALLEYS/ADJACENT PLAINS AFTER 21Z. KALS AND KCOS CARRY THE BEST PROBABILITIES FOR TSRA...AND WILL MAINTAIN VCTS FOR BOTH...THOUGH WILL BE ADDING A TEMPO GROUP FOR ERRATIC OUTFLOW WINDS DURING THE 22Z-01Z TIMEFRAME. THUNDERSTORMS WILL BRING BRIEF MVFR CIGS/VIS SHOULD THEY HIT THE TERMINALS. THUNDERSTORMS SHOULD DIMINISH AFTER SUNSET FOR THE TERMINALS WITH SOME MID/HIGH DECK OF CLOUDINESS PERSISTING OVERNIGHT WHICH SHOULD PREVENT FORMATION OF ANY FOG/LOW STRATUS AT TERMINALS OVERNIGHT. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ROSE SHORT TERM...ROSE LONG TERM...HODANISH AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
707 AM MDT MON AUG 5 2013 .UPDATE... ISSUED AT 703 AM MDT MON AUG 5 2013 UPDATED GRIDS/ZONES FOR SLIGHTLY LESS SKY COVERAGE OVER PORTIONS OF THE PLAINS...AND TO DROP LOW POPS FOR THE MTS FOR THE EARLY MON MORNING PERIOD. HIGH CLOUDS CONTINUE TO STREAM UP FROM THE SOUTH...SO STILL THINK WE WILL SEE MORE CLOUDS THAN SUN TODAY. MOST RECENT HRRR IS SHOWING FAIRLY STRONG QPF MOVING OVER THE WALDO AND BLACK FOREST AREAS AFTER 23Z TODAY...WHILE OTHER MODELS ARE A BIT MORE SPARSE. WILL HAVE TO WATCH CONVECTIVE TRENDS CLOSELY THIS AFTERNOON GIVEN THE RECENT HEAVY RAINS. ROSE && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM MDT MON AUG 5 2013 ...A BIT QUIETER TODAY...STILL SOME FLOODING CONCERNS... CURRENTLY...JUST A FEW SHOWERS LINGERING NR THE KS AND OK BORDERS. KALS FINALLY DRYING OUT AFTER A COUPLE HOURS OF SOME FAIRLY GOOD RAINFALL...NEARLY HALF AN INCH...MOST OF WHICH WAS INVISIBLE TO RADAR DUE TO BLOCKAGE AND DISTANCE FROM THE WSR NETWORK. WILL PROBABLY SEE SOME LOW CLOUDS IN THE VALLEY THIS MORN. OTHERWISE...JUST SOME LOW CLOUDS AND A BIT OF FG POSSIBLE OVER THE FAR SERN PLAINS...ESPECIALLY KIOWA COUNTY. MAIN CONCERN TODAY WILL BE AN UPPER LEVEL DISTURBANCE THAT IS EMBEDDED UNDER THE RIDGE...WHICH CAN BE SEEN CURRENTLY KICKING OFF CONVECTION OVR NM. THIS WILL PROPAGATE THRU WRN CO THIS MORN. MAIN LIFT AND FOCUS FOR CONVECTION WILL BE LATER TODAY OVER KS...SO BELIEVE THAT THE BIGGEST IMPACT FROM THE DISTURBANCE WILL BE MOSTLY E OF OUR CWA. HOWEVER...WILL STILL SEE SCT STORMS DEVELOP EARLY TODAY OVER THE MTS...SPREADING TO THE I-25 CORRIDOR LATE IN THE AFTERNOON. SO...WILL STILL HAVE TO KEEP A CLOSE EYE OUT ON THE BURN SCARS EVEN THOUGH THE INTENSITY AND COVERAGE OF STORMS LOOKS A BIT LESS. FOR THE FAR ERN PLAINS...NR THE KS BORDER...THERE COULD BE MORE VIGOROUS CONVECTION...INCLUDING THE POTENTIAL FOR A STRONG STORM OR TWO...BUT BELIEVE THAT MOST OF THE HEAVY RAIN IMPACT WILL STAY FAR ENOUGH E TO PRESENT A SMALLER RISK FOR THE RIVERS. HAVE ALREADY ISSUED A COUPLE FLOOD WARNINGS FOR THE ARKANSAS AND PURGATOIRE...BUT THESE SPOTS SHOULD CREST AND BEGIN TO RECEDE LATER THIS MORNING. EXTENSIVE MID AND HIGH CLOUDS WILL CONTINUE TO LIMIT TEMPS TODAY...BUT WITH THE RIDGE BUILDING A BIT IT SHOULD BE A COUPLE DEGREES WARMER FOR MOST SPOTS THIS AFTERNOON. HIGH CLOUDS WILL THICKEN UP A BIT OVERNIGHT ESPECIALLY FOR THE NRN AND WRN PORTIONS OF THE CWA...LEADING TO ANOTHER MILD NIGHT. ROSE .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 355 AM MDT MON AUG 5 2013 ...WEDNESDAY COULD BE A RATHER WET AND STORMY DAY... NOT MUCH OVERALL CHANGE IN THE GUIDANCE. AS HAS BEEN STATED OVER THE LAST SEVERAL DAYS...THE MONSOON PLUME WILL REMAIN IN PLACE OVER THE FCST AREA THROUGH THIS FCST PERIOD...AND THIS PATTER N WILL KEEP THE REGION RATHER WET WITH SEASONABLE TEMPERATURES. THE MAIN DAY OF CONCERN APPEARS TO BE WEDNESDAY. NEARLY ALL SIMULATIONS ARE SHOWING THIS DAY IS LIKELY GOING TO BE WET...AND WE WILL LIKELY SEE OUR BEST CHANCE OF HEAVY RAINS OVER THE REGION. QUITE A FEW AREAS HAVE HAD DECENT RAINFALL IN THE LAST WEEK OR SO...SO FLASH FLOODING CONCERNS ARE GOING TO BE MORE WIDESPREAD WITH THIS EVENT (JUST NOT THE BURN SCARS). SIMULATIONS CONTINUE TO INDICATE SEVERAL FEATURES WILL COME INTO PLAY TO BRING THE THREAT OF HEAVY RAIN WEDNESDAY. FIRST...A COOL FRONT WILL MOVE IN TUESDAY NIGHT...BRINGING ANOTHER SURGE OF LLVL MOISTURE INTO THE REGION. THE UPPER LEVEL MONSOON PLUME WILL CONTINUE OVER THE REGION ADDING TO THE MOISTURE ALOFT. ADDITIONALLY...A WELL DEFINED DISTURBANCE WILL MOVE ACROSS THE REGION DURING THE DAY WEDNESDAY...AND THIS FEATURE WILL CREATE FAVORABLE DIFFLUENCE ALOFT TO ACCENTUATE THE UPWARD VERTICAL VELOCITY FIELDS OVER THE REGION. ALL THESE FEATURES COMING TOGETHER SHOULD ALLOW FOR HEAVY CONVECTIVE PRECIP WED. THE ONLY CONCERN I SEE FOR WED IS THAT CAPE MAY BE LIMITED AS IT MAY BE QUITE CLOUDY AND COOL...AND WITH LIMITED INSOLATION...CAPE VALUES MAY NOT GET TOO HIGH. IF WE DO SEE SOME SUN THEN THE THREAT OF HEAVIER RAIN WILL INCREASE. THERE IS ALSO A CHANCE THE CONVECTION MAY BE SEVERE ON THIS DAY (ESPECIALLY IF WE CAN GET SOME DECENT CAPE) AS SHEAR WILL BE MARGINAL FOR ROTATING STORMS. WITH THE LIKELY LOW LCLS...A FEW WEAK SUPERCELL TORNADOES WILL BE POSSIBLE. WRT TO THE NDFD GRIDS...I HAVE LIKELY POPS OVER THE MTNS WED WITH HIGH SCTD POPS ON THE PLAINS. I MENTIONED HEAVY RAIN (R+) IN THE WEATHER GRIDS. IT IS TOO EARLY TO MENTION SVR IN THE NDFD. IN THE MEANTIME...TUESDAY WE WILL SEE SCATTERED STORMS OVER THE MTNS WITH SCTD ACTIVITY MOVING ONTO THE PLAINS LATE IN THE DAY. TUESDAY NIGHT THE COOL FRONT WILL MOVE DOWN...AND I CANNOT RULE OUT SOME LOCALLY HEAVY RAIN THIS EVENING/NIGHT AS AN MCS MAY FORM ON THE SE PLAINS. WEDNESDAY WILL BE BUSY AS ALLUDED TO ABOVE. THURSDAY INTO THE WEEKEND CONTINUES TO LOOK BUSY. UPSLOPE WILL CONTINUE IN THE LLVLS AND MSTR WILL CONTINUE ALOFT WITH THE PERSISTENT SW MONSOON FLOW. NO WELL DEFINED SHORT WAVES ARE EXPECTED...BUT THERE WILL BE ENOUGH FORCING/INSTABILITY TO CONTINUE THE THREAT OF AFTERNOON AND EVENING SHOWER AND STORMS OVER THE ENTIRE REGION. SOME OF THE RAIN WILL BE LOCALLY HEAVY. /HODANISH && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 355 AM MDT MON AUG 5 2013 MAIN CONCERNS WILL BE POTENTIAL FOR STORMS LATER TODAY...ALONG WITH SOME LOCALIZED AREAS OF LOW CIGS AND EVEN SOME PC FG. MOST OF THE LOW CIGS WILL STAY E OF THE KS BORDER THIS MORNING...ALTHOUGH KALS COULD SEE SOME BRIEF LOW CLOUDS OR BR DUE TO THE OVERNIGHT RAINFALL IN THE SAN LUIS VALLEY. SCT TS SHOULD GET GOING FAIRLY QUICKLY TODAY OVER THE CENTRAL AND SW MTS...BUT MOST OF THE HEAVIER PRECIP SHOULD REMAIN OVER THE HYR TRRN. A FEW STORMS MIGHT SURVIVE TO THE VC OF KCOS AND POSSIBLY KPUB AFTER 21Z TODAY. ROSE && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ROSE SHORT TERM...ROSE LONG TERM...HODANISH AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS MIAMI FL
801 PM EDT TUE AUG 6 2013 .UPDATE... ONLY ISOLATED THUNDERSTORMS REMAIN EARLY THIS EVENING ACROSS MAINLY INLAND BROWARD COUNTY AND LAKE OKEECHOBEE. THESE STORMS CONTINUE TO WEAKEN AND SHOULD DISSIPATE OVER THE NEXT FEW HOURS. WINDS SHOULD REMAIN LIGHT OVERNIGHT BEFORE TURNING MORE EASTERLY ON WEDNESDAY THROUGH THE REMAINDER OF THE WEEK. && .PREV DISCUSSION... /ISSUED 745 PM EDT TUE AUG 6 2013/ AVIATION... CONVECTION CONFINED TO INTERIOR PORTIONS WITH TAF SITES NOT EXPECTED TO BE IMPACTED THE REMAINING OF THIS EVENING. OVERNIGHT LOW LEVEL EASTERLY FLOW REGIME WILL BE BUILDING ACROSS THE AREA AND WITH THAT PATTERN FAVORING OVERNIGHT EAST COAST SHOWERS AND AFTERNOON/EVENING THUNDERSTORMS WEST COAST WILL GRADUALLY EMERGE. HENCE, TAFS INCLUDE VCSH FOR THE OVERNIGHT MORNING HOURS ALONG EAST COAST SITES AND VCTS FOR THE AFTERNOON/EVENING HOURS AT APF TOMORROW. ACTIVITY IS LIKELY TO BE SOMEWHAT CONFINED TOMORROW AS IT WAS TODAY DUE TO AREA BEING UNDER SUPPRESSING INFLUENCE OF MID LEVEL RIDGE ACROSS THE NW GULF AND BACK SIDE OF UPPER LEVEL LOW NORTH OF HISPANIOLA. ALL IN ALL VFR CONDITIONS FORECAST FOR ALL SITES THROUGH FORECAST PERIOD OUTSIDE THE OFF CHANCE OF A STORM MOVING OVER A SITE. WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT BECOMING SOUTHEAST 5 TO 10 KNOTS EAST COAST SITES LATE TOMORROW MORNING OR EARLY AFTERNOON AND ONSHORE EARLY AFTERNOON AT APF AS SEA BREEZE DEVELOPS. PREV DISCUSSION... /ISSUED 253 PM EDT TUE AUG 6 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... A MID/UPPER LEVEL RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHERN STATES INTO THE ATLANTIC WITH AN INVERTED TROUGH MOVING WEST ACROSS THE EASTERN BAHAMAS BENEATH THE RIDGE AXIS. AT THE SURFACE, A WEAK SURFACE TROUGH EXTENDS FROM SOUTH FLORIDA INTO THE NORTHERN BAHAMAS AND INTO THE CENTRAL ATLANTIC. THE SURFACE TROUGH IS A VERY SHALLOW FEATURE AND THIS COMBINED WITH THE UPPER TROUGH TO THE EAST AND RIDGE TO THE NORTH IS RESULTING IN VERY WEAK SURFACE PRESSURE GRADIENT BECOMING NORTH TO NORTHEAST FLOW ABOVE 5K FT. THE 12Z MFL SOUNDING CAPTURED THIS WELL AND ALSO SHOWS PWAT REMAINING AT AROUND TWO INCHES. ALL OF THIS SPELLS CONVECTIVE DEVELOPMENT MOVING OFF TO THE SOUTH AND THE HRRR HAS BEEN INDICATING THIS ALSO WITH GOOD INITIAL TIMING AND LOCATION. THE SOUNDING ALSO SHOWED MID LEVEL LAPSE RATES QUITE WEAK AT 5.8 DEGREES CELSIUS/KM AND A 500 MB TEMPERATURE OF ONLY -5.9 WHICH IS NEARLY TWO DEGREES WARMER THAN AVERAGE FOR EARLY AUGUST SO ONLY ISOLATED STRONG STORMS ARE EXPECTED THIS AFTERNOON AT BEST. THE MID LEVEL TROUGH WILL CONTINUE MOVING TO THE WEST IN THE SHORT TERM WITH ALL GLOBAL MODELS IN VERY GOOD AGREEMENT SHIFTING IT INTO THE CENTRAL BAHAMAS ON WEDNESDAY AND THE WESTERN BAHAMAS BY LATE THURSDAY. AS THE TROUGH APPROACHES SOUTH FLORIDA, THE EASTERLY FLOW WILL DEEPEN AS THE UPPER RIDGE TO THE NORTH MOVES LITTLE THROUGH THIS PERIOD. THE ATMOSPHERIC MOISTURE PROFILE WILL CHANGE LITTLE THROUGH WEDNESDAY AND WITH THE EAST FLOW DEEPENING, THE PRIMARY THREAT FOR CONVECTIVE ACTIVITY WILL TEND TO BE MORNING SHOWERS ALONG THE EAST COAST AND THEN SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING OVER THE INTERIOR DURING THE AFTERNOON AND MOVING TOWARDS THE SOUTHWEST COAST. THE STEERING WINDS ARE ONLY EXPECTED TO BE AROUND 5 MPH SO THE THREAT WILL EXIST FOR POSSIBLE LOCALLY HEAVY RAINS IN THE NAPLES AREA. THERE COULD ACTUALLY BE LESS ACTIVITY ON THURSDAY AS THE TROUGH APPROACHES WHICH PLACES SOUTH FLORIDA ON THE SUBSIDENCE SIDE. THIS TROUGH CURRENTLY SHOWS UP VERY WELL IN WATER VAPOR IMAGERY WITH STRONG SUBSIDENCE SHOWING UP TO ITS WEST. THE MODELS ALSO SHOW THE LOW MAINTAINING ITS CURRENT STRENGTH SO ANOTHER REASON THERE COULD BE LESS ACTIVITY. BY THURSDAY NIGHT, THE ATMOSPHERE WILL UNDERGO GOOD DESTABILIZATION AS THE TROUGH MOVES INTO THE STRAITS OF FLORIDA. THE GFS IS INDICATING 500 MB TEMPERATURES COOLING TO -11 SOUTHEAST OF KEY LARGO AND -10 OFF THE SOUTHEAST COAST. THE NAM IS A TAD BID SLOWER WITH THE MOVEMENT BUT STILL SHOWS THIS SAME COLD POOL ABOUT 50-100 MILES TO THE SOUTHEAST OF THE GFS POSITION. AT ANY RATE, THIS COULD SET OFF SOME IMPRESSIVE LIGHTNING DISPLAYS TO OUR SOUTHEAST THURSDAY EVENING AND NIGHT AS CONVECTIVE CELLS COULD EASILY DEVELOP OVER THE ATLANTIC WATERS WITH SUCH COLD TEMPERATURES ALOFT MOVING ACROSS THE GULF STREAM WATERS MAKING THE ENVIRONMENT VERY UNSTABLE. BUT AS ALWAYS AS WE GET OUT WITH TIME, CONFIDENCE IS LESS SO IT IS A WAIT AND SEE APPROACH. LONG TERM (FRIDAY-TUESDAY)... LATE IN THE WEEK AND INTO THE WEEKEND AND EARLY NEXT WEEK, THE TROUGH WILL CONTINUE WESTWARD INTO THE GULF OF MEXICO ALLOWING THE ATLANTIC RIDGE TO ALSO BUILD WEST. THIS WILL STABILIZE THE ATMOSPHERE ONCE AGAIN AND THE GFS IS ALSO SHOWING SIGNIFICANT DRYING TAKING PLACE WITH PWAT DROPPING WELL UNDER TWO INCHES. SO WHILE FRIDAY COULD REMAIN QUITE ACTIVE, MUCH LESS ACTIVITY IS LIKELY AS WE GET INTO THE WEEKEND AND CROSS OVER INTO NEXT WEEK. MARINE... LIGHT AND VARIABLE WIND TONIGHT WILL SLOWLY BECOME EAST BY WEDNESDAY AND THEN STRENGTHENING LATER IN THE WEEK AS THE GRADIENT TIGHTENS. THIS WILL BUILD SEAS OVER THE NEXT COUPLE OF DAYS BUT REMAIN WELL BELOW ADVISORY CRITERIA. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 76 89 78 89 / 20 20 20 20 FORT LAUDERDALE 78 90 81 90 / 20 20 20 20 MIAMI 78 91 79 89 / 20 20 20 20 NAPLES 77 92 76 93 / 20 40 30 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...10/CD AVIATION/RADAR...52/PS
AREA FORECAST DISCUSSION
NWS MIAMI FL
745 PM EDT TUE AUG 6 2013 .AVIATION... CONVECTION CONFINED TO INTERIOR PORTIONS WITH TAF SITES NOT EXPECTED TO BE IMPACTED THE REMAINING OF THIS EVENING. OVERNIGHT LOW LEVEL EASTERLY FLOW REGIME WILL BE BUILDING ACROSS THE AREA AND WITH THAT PATTERN FAVORING OVERNIGHT EAST COAST SHOWERS AND AFTERNOON/EVENING THUNDERSTORMS WEST COAST WILL GRADUALLY EMERGE. HENCE, TAFS INCLUDE VCSH FOR THE OVERNIGHT MORNING HOURS ALONG EAST COAST SITES AND VCTS FOR THE AFTERNOON/EVENING HOURS AT APF TOMORROW. ACTIVITY IS LIKELY TO BE SOMEWHAT CONFINED TOMORROW AS IT WAS TODAY DUE TO AREA BEING UNDER SUPPRESSING INFLUENCE OF MID LEVEL RIDGE ACROSS THE NW GULF AND BACK SIDE OF UPPER LEVEL LOW NORTH OF HISPANIOLA. ALL IN ALL VFR CONDITIONS FORECAST FOR ALL SITES THROUGH FORECAST PERIOD OUTSIDE THE OFF CHANCE OF A STORM MOVING OVER A SITE. WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT BECOMING SOUTHEAST 5 TO 10 KNOTS EAST COAST SITES LATE TOMORROW MORNING OR EARLY AFTERNOON AND ONSHORE EARLY AFTERNOON AT APF AS SEA BREEZE DEVELOPS. && .PREV DISCUSSION... /ISSUED 253 PM EDT TUE AUG 6 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... A MID/UPPER LEVEL RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHERN STATES INTO THE ATLANTIC WITH AN INVERTED TROUGH MOVING WEST ACROSS THE EASTERN BAHAMAS BENEATH THE RIDGE AXIS. AT THE SURFACE, A WEAK SURFACE TROUGH EXTENDS FROM SOUTH FLORIDA INTO THE NORTHERN BAHAMAS AND INTO THE CENTRAL ATLANTIC. THE SURFACE TROUGH IS A VERY SHALLOW FEATURE AND THIS COMBINED WITH THE UPPER TROUGH TO THE EAST AND RIDGE TO THE NORTH IS RESULTING IN VERY WEAK SURFACE PRESSURE GRADIENT BECOMING NORTH TO NORTHEAST FLOW ABOVE 5K FT. THE 12Z MFL SOUNDING CAPTURED THIS WELL AND ALSO SHOWS PWAT REMAINING AT AROUND TWO INCHES. ALL OF THIS SPELLS CONVECTIVE DEVELOPMENT MOVING OFF TO THE SOUTH AND THE HRRR HAS BEEN INDICATING THIS ALSO WITH GOOD INITIAL TIMING AND LOCATION. THE SOUNDING ALSO SHOWED MID LEVEL LAPSE RATES QUITE WEAK AT 5.8 DEGREES CELSIUS/KM AND A 500 MB TEMPERATURE OF ONLY -5.9 WHICH IS NEARLY TWO DEGREES WARMER THAN AVERAGE FOR EARLY AUGUST SO ONLY ISOLATED STRONG STORMS ARE EXPECTED THIS AFTERNOON AT BEST. THE MID LEVEL TROUGH WILL CONTINUE MOVING TO THE WEST IN THE SHORT TERM WITH ALL GLOBAL MODELS IN VERY GOOD AGREEMENT SHIFTING IT INTO THE CENTRAL BAHAMAS ON WEDNESDAY AND THE WESTERN BAHAMAS BY LATE THURSDAY. AS THE TROUGH APPROACHES SOUTH FLORIDA, THE EASTERLY FLOW WILL DEEPEN AS THE UPPER RIDGE TO THE NORTH MOVES LITTLE THROUGH THIS PERIOD. THE ATMOSPHERIC MOISTURE PROFILE WILL CHANGE LITTLE THROUGH WEDNESDAY AND WITH THE EAST FLOW DEEPENING, THE PRIMARY THREAT FOR CONVECTIVE ACTIVITY WILL TEND TO BE MORNING SHOWERS ALONG THE EAST COAST AND THEN SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING OVER THE INTERIOR DURING THE AFTERNOON AND MOVING TOWARDS THE SOUTHWEST COAST. THE STEERING WINDS ARE ONLY EXPECTED TO BE AROUND 5 MPH SO THE THREAT WILL EXIST FOR POSSIBLE LOCALLY HEAVY RAINS IN THE NAPLES AREA. THERE COULD ACTUALLY BE LESS ACTIVITY ON THURSDAY AS THE TROUGH APPROACHES WHICH PLACES SOUTH FLORIDA ON THE SUBSIDENCE SIDE. THIS TROUGH CURRENTLY SHOWS UP VERY WELL IN WATER VAPOR IMAGERY WITH STRONG SUBSIDENCE SHOWING UP TO ITS WEST. THE MODELS ALSO SHOW THE LOW MAINTAINING ITS CURRENT STRENGTH SO ANOTHER REASON THERE COULD BE LESS ACTIVITY. BY THURSDAY NIGHT, THE ATMOSPHERE WILL UNDERGO GOOD DESTABILIZATION AS THE TROUGH MOVES INTO THE STRAITS OF FLORIDA. THE GFS IS INDICATING 500 MB TEMPERATURES COOLING TO -11 SOUTHEAST OF KEY LARGO AND -10 OFF THE SOUTHEAST COAST. THE NAM IS A TAD BID SLOWER WITH THE MOVEMENT BUT STILL SHOWS THIS SAME COLD POOL ABOUT 50-100 MILES TO THE SOUTHEAST OF THE GFS POSITION. AT ANY RATE, THIS COULD SET OFF SOME IMPRESSIVE LIGHTNING DISPLAYS TO OUR SOUTHEAST THURSDAY EVENING AND NIGHT AS CONVECTIVE CELLS COULD EASILY DEVELOP OVER THE ATLANTIC WATERS WITH SUCH COLD TEMPERATURES ALOFT MOVING ACROSS THE GULF STREAM WATERS MAKING THE ENVIRONMENT VERY UNSTABLE. BUT AS ALWAYS AS WE GET OUT WITH TIME, CONFIDENCE IS LESS SO IT IS A WAIT AND SEE APPROACH. LONG TERM (FRIDAY-TUESDAY)... LATE IN THE WEEK AND INTO THE WEEKEND AND EARLY NEXT WEEK, THE TROUGH WILL CONTINUE WESTWARD INTO THE GULF OF MEXICO ALLOWING THE ATLANTIC RIDGE TO ALSO BUILD WEST. THIS WILL STABILIZE THE ATMOSPHERE ONCE AGAIN AND THE GFS IS ALSO SHOWING SIGNIFICANT DRYING TAKING PLACE WITH PWAT DROPPING WELL UNDER TWO INCHES. SO WHILE FRIDAY COULD REMAIN QUITE ACTIVE, MUCH LESS ACTIVITY IS LIKELY AS WE GET INTO THE WEEKEND AND CROSS OVER INTO NEXT WEEK. AVIATION... ISOLATED HEAVY SHOWERS AND STORMS HAVE ALREADY DEVELOPED THIS AFTERNOON ACROSS PORTIONS OF THE AREA...MOSTLY SOUTH OF A LINE FROM FLL TO APF WITH THE MEAN LOW-LEVEL NORTHERLY FLOW IN PLACE. ALTHOUGH MOST OF THE AFTERNOON/EVENING ACTIVITY SHOULD REMAIN JUST INLAND OF THE TAF SITES...WE WILL CONTINUE TO INCLUDE VCTS AT MOST SITES FROM 21Z THROUGH THE EVENING HOURS AND UPDATE AS CONDITIONS EVOLVE. OVERNIGHT TONIGHT THROUGH WEDNESDAY...THE FLOW SHOULD BECOME MORE EASTERLY...WHICH WILL TRANSLATE TO THE BEST RAINFALL CHANCES SETTING UP ACROSS THE INTERIOR AND WESTERN LOCATIONS OF SOUTH FLORIDA THROUGH THE DAY WEDNESDAY. MARINE... LIGHT AND VARIABLE WIND TONIGHT WILL SLOWLY BECOME EAST BY WEDNESDAY AND THEN STRENGTHENING LATER IN THE WEEK AS THE GRADIENT TIGHTENS. THIS WILL BUILD SEAS OVER THE NEXT COUPLE OF DAYS BUT REMAIN WELL BELOW ADVISORY CRITERIA. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 76 89 78 89 / 20 20 20 20 FORT LAUDERDALE 78 90 81 90 / 20 20 20 20 MIAMI 78 91 79 89 / 20 20 20 20 NAPLES 77 92 76 93 / 20 40 30 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...10/CD AVIATION/RADAR...52/PS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
132 PM EDT MON AUG 5 2013 .SYNOPSIS... A WEAK BACKDOOR COLD FRONT WILL BECOME NEARLY STATIONARY ACROSS SOUTHERN GEORGIA TODAY...THEN LINGER INTO MID WEEK BEFORE DISSIPATING AS HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. ATLANTIC HIGH PRESSURE WILL THEN PREVAIL LATE IN THE WEEK INTO THE WEEKEND...BEFORE ANOTHER BACKDOOR COLD FRONT AFFECTS THE AREA LATE IN THE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE FORECAST IS PRETTY MUCH EVOLVING AS EXPECTED. ONLY MINOR CHANGES WERE MADE WITH THE EARLY AFTERNOON UPDATE. MID-MORNING SURFACE ANALYSIS SHOWS THE BACKDOOR COLD FRONT HAS BECOME STATIONARY SOUTH OF THE ALTAMAHA RIVER WITH A COOL EAST/NORTHEAST FLOW PREVAILING ACROSS THE AREA. SHOWERS ARE BEGINNING TO BREAKOUT ALONG PORTIONS OF NORTH COASTAL GEORGIA AHEAD OF WHAT APPEARS TO BE THE 850MB COLD FRONT. HIGH RESOLUTION MODELS ARE SIMILAR IN DEVELOPING ADDITIONAL SHOWERS/TSTMS OVER THE NEXT FEW HOURS ACROSS MAINLY SOUTHEAST GEORGIA SOUTH OF I-16 COINCIDENT WITH THE STRONGEST 850MB CONVERGENCE AXIS. WILL INCREASE POPS TO 30 PERCENT IN THIS AREA THROUGH EARLY AFTERNOON WITH POPS DIMINISHING TO SLIGHT CHANCE LATER THIS AFTERNOON AS THE LATEST RAP SHOWS 850MB CONVERGENCE DIMINISHING WITH TIME. THE WEATHER LOOKS DRY FOR MUCH OF SOUTHEAST SOUTH CAROLINA TODAY. HIGHS WILL RANGE FROM THE MID 80S ACROSS THE CHARLESTON TRI-COUNTY AREA TO AROUND 90 ACROSS THE FAR SOUTHWEST ZONES. TEMPERATURES ALONG THE BEACHES OF CHARLESTON COUNTY WILL LIKELY ONLY TOP OUT IN THE LOWER 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... TONIGHT...ANY SHOWERS/STORMS WILL DIMINISH AND/OR PUSH FARTHER INLAND LEADING TO A RATHER DRY NIGHT WITH LOWS AROUND 70 INLAND AND MID/UPPER 70S NEAR THE COAST. TUESDAY AND TUESDAY NIGHT...A MID AND UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL EXPAND EASTWARD OVER THE REGION. MEANWHILE AT THE SURFACE...THE FORMER BACKDOOR COLD FRONT WILL REMAIN NEARLY STATIONARY IN THE VICINITY OF THE FLORIDA/GEORGIA BORDER AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE NORTHEAST. ONSHORE LOW LEVEL TRAJECTORIES WILL ADVECT MOISTURE INTO THE AREA...ESPECIALLY ACROSS SOUTHEAST GEORGIA WHERE ITS CLOSER PROXIMITY TO THE STALLED FRONT FAVORS THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS IN THE AFTERNOON. THE LACK OF DEEPER MOISTURE FARTHER TO THE NORTHEAST WILL RESULT IN LESS COVERAGE OF SHOWERS AND THUNDERSTORMS WITH SOME AREAS CLOSER TO THE SOUTH CAROLINA COAST POSSIBLY REMAINING RAIN-FREE. WITH THE LOSS OF DIURNAL HEATING ALL CONVECTION WILL DISSIPATE BY MID-EVENING OR SO. THE COOLER ONSHORE FLOW SHOULD ONLY ALLOW TEMPERATURES TO REACH HIGHS IN THE UPPER 80S TO AROUND 90 INLAND AWAY FROM THE COAST. LOWS TUESDAY NIGHT WILL ACTUALLY BE UNSEASONABLY COOL...IN THE UPPER 60S TO LOWER 70S. WEDNESDAY AND WEDNESDAY NIGHT...A WEAK SHORT WAVE DISTURBANCE WILL PASS MAINLY NORTH OF THE AREA ON WEDNESDAY...BUT CAUSE SOME WEAKNESS ALONG THE EASTERN PERIPHERY OF THE MID AND UPPER LEVEL RIDGE. AT THE SURFACE...HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTHEAST AS THE STALLED FRONT TO THE SOUTH DISSIPATES. DESPITE THE PASSAGE OF THE DISTURBANCE...MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING LITTLE IN THE WAY OF CONVECTION OVER THE AREA. THE FORECAST WILL INDICATE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH CAROLINA DURING THE AFTERNOON...MAINLY BECAUSE THE DEEPEST MOISTURE WILL REMAIN OVER THESE AREAS. DAYTIME HIGHS WILL REMAIN IN THE UPPER 80S TO AROUND 90...WITH LOWS WEDNESDAY NIGHT AROUND 70 OR IN THE LOWER 70S INLAND FROM THE BEACHES. THURSDAY...THE MID AND UPPER LEVEL RIDGE WILL EXPAND AND BECOME WEST-EAST ORIENTED OVER THE REGION AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WESTERN ATLANTIC. THIS IS A MORE TYPICAL SUMMERTIME PATTERN...WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO OCCUR ALONG AND AHEAD OF THE SEA BREEZE IN THE AFTERNOON AND EARLY EVENING. TEMPERATURES WILL WARM AS THE FLOW BECOMES MORE SOUTHERLY...WITH HIGHS IN THE LOWER 90S AWAY FROM THE COAST. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH MOST OF THE LONG TERM PERIOD...LEADING TO A HIGHER THAN NORMAL CONFIDENCE FORECAST. AN EXPANSIVE UPPER LEVEL RIDGE WILL PREVAIL OVER THE REGION THROUGH SATURDAY...BEFORE A LONG WAVE TROUGH EXPANDS ACROSS THE EASTERN U.S. LATE IN THE WEEKEND INTO EARLY NEXT WEEK. AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL PREVAIL INTO THE WEEKEND...THEN A BACKDOOR COLD FRONT APPEARS POISED TO AFFECT THE AREA LATE SUNDAY AND MONDAY. CONVECTION WILL BE DIURNALLY DRIVEN THROUGH SATURDAY...WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED ALONG AND AHEAD OF THE SEA BREEZE EACH AFTERNOON AND EARLY EVENING. THE PROBABILITY OF SHOWERS AND THUNDERSTORMS SHOULD INCREASE LATE IN THE WEEKEND INTO EARLY NEXT WEEK IN ASSOCIATION WITH THE BACKDOOR COLD FRONT. TEMPERATURES SHOULD BE NEAR NORMAL THROUGH MOST OF THE LONG TERM...WITH THE WARMEST TEMPERATURES LIKELY COMING SATURDAY WITH SOME COMPRESSIONAL HEATING AHEAD OF THE FRONT. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... THERE IS A SMALL RISK THAT AN ISOLATED SHOWER COULD IMPACT KSAV THIS AFTERNOON AS A STALLED FRONT REMAINS TO THE SOUTH. STILL...EXPECT MAINLY VFR CONDITIONS TO PREVAIL AT BOTH KCHS AND KSAV. THE MAIN ISSUE THROUGH THE AFTERNOON WILL REMAIN GUSTY EAST SOUTHEASTERLY WINDS DUE TO THE PINCHED GRADIENT. AS SUNSET NEARS...GUSTS WILL SUBSIDE. OVERNIGHT... SOME LOWER CEILINGS ARE POSSIBLE AT KSAV AS LOW LEVEL MOISTURE POOLS IN THE VICINITY OF THE STALLED FRONT...BUT WILL MAINTAIN VFR CONDITIONS FOR NOW. EXTENDED AVIATION OUTLOOK...ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE EACH AFTERNOON/EARLY EVENING AND COULD RESULT IN BRIEF REDUCTIONS IN CEILINGS/VISIBILITIES. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO PREVAIL. && .MARINE... TODAY...A BACKDOOR COLD FRONT NEAR THE SAVANNAH RIVER WILL PUSH SOUTHWARD LEADING TO A SURGE OF EAST/NORTHEAST WINDS...AS HIGH AS 15-20 KT AT TIMES OVER THE SC WATERS. SEAS WILL RESPOND A BIT AS WELL BUT SHOULD STAY 4 FT OR LESS...HIGHEST OFFSHORE. THUS...NO ADVISORIES ARE EXPECTED. TONIGHT...MAINLY EAST WINDS EXPECTED AOB 15 KT AS HIGH PRESSURE REMAINS NORTH OF THE AREA WITH LOW PRESSURE TO THE SOUTH. TUESDAY THROUGH SATURDAY...A BACKDOOR COLD FRONT WILL STALL JUST SOUTH OF THE WATERS INTO WEDNESDAY BEFORE DISSIPATING...MAINTAINING AN ONSHORE FLOW ACROSS THE WATERS. THE FLOW WILL VEER SOUTHERLY LATER IN THE WEEK AS HIGH PRESSURE BUILDS IN FROM THE WESTERN ATLANTIC. IN GENERAL...WINDS SHOULD REMAIN AT OR BELOW 15 KT...HIGHEST NEAR SEABREEZE CIRCULATIONS ALONG THE COAST. SEAS WILL RANGE BETWEEN 1-3 FT...HIGHEST OVER OUTER GEORGIA WATERS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST/JHP
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1003 AM EDT MON AUG 5 2013 .SYNOPSIS... A WEAK BACKDOOR COLD FRONT WILL BECOME NEARLY STATIONARY ACROSS SOUTHERN GEORGIA TODAY...THEN LINGER INTO MID WEEK BEFORE DISSIPATING AS HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. ATLANTIC HIGH PRESSURE WILL THEN PREVAIL LATE IN THE WEEK INTO THE WEEKEND...BEFORE ANOTHER BACKDOOR COLD FRONT AFFECTS THE AREA LATE IN THE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MID-MORNING SURFACE ANALYSIS SHOWS THE BACKDOOR COLD FRONT HAS BECOME STATIONARY SOUTH OF THE ALTAMAHA RIVER WITH A COOL EAST/NORTHEAST FLOW PREVAILING ACROSS THE AREA. SHOWERS ARE BEGINNING TO BREAKOUT ALONG PORTIONS OF NORTH COASTAL GEORGIA AHEAD OF WHAT APPEARS TO BE THE 850MB COLD FRONT. HIGH RESOLUTION MODELS ARE SIMILAR IN DEVELOPING ADDITIONAL SHOWERS/TSTMS OVER THE NEXT FEW HOURS ACROSS MAINLY SOUTHEAST GEORGIA SOUTH OF I-16 COINCIDENT WITH THE STRONGEST 850MB CONVERGENCE AXIS. WILL INCREASE POPS TO 30 PERCENT IN THIS AREA THROUGH EARLY AFTERNOON WITH POPS DIMINISHING TO SLIGHT CHANCE LATER THIS AFTERNOON AS THE LATEST RAP SHOWS 850MB CONVERGENCE DIMINISHING WITH TIME. THE WEATHER LOOKS DRY FOR MUCH OF SOUTHEAST SOUTH CAROLINA TODAY. HIGHS WILL RANGE FROM THE MID 80S ACROSS THE CHARLESTON TRI-COUNTY AREA TO AROUND 90 ACROSS THE FAR SOUTHWEST ZONES. TEMPERATURES ALONG THE BEACHES OF CHARLESTON COUNTY WILL LIKELY ONLY TOP OUT IN THE LOWER 80S. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... TONIGHT...ANY SHOWERS/STORMS WILL DIMINISH AND/OR PUSH FARTHER INLAND LEADING TO A RATHER DRY NIGHT WITH LOWS AROUND 70 INLAND AND MID/UPPER 70S NEAR THE COAST. TUESDAY AND TUESDAY NIGHT...A MID AND UPPER LEVEL RIDGE CENTERED OVER THE SOUTHERN PLAINS WILL EXPAND EASTWARD OVER THE REGION. MEANWHILE AT THE SURFACE...THE FORMER BACKDOOR COLD FRONT WILL REMAIN NEARLY STATIONARY IN THE VICINITY OF THE FLORIDA/GEORGIA BORDER AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE NORTHEAST. ONSHORE LOW LEVEL TRAJECTORIES WILL ADVECT MOISTURE INTO THE AREA...ESPECIALLY ACROSS SOUTHEAST GEORGIA WHERE ITS CLOSER PROXIMITY TO THE STALLED FRONT FAVORS THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS IN THE AFTERNOON. THE LACK OF DEEPER MOISTURE FARTHER TO THE NORTHEAST WILL RESULT IN LESS COVERAGE OF SHOWERS AND THUNDERSTORMS WITH SOME AREAS CLOSER TO THE SOUTH CAROLINA COAST POSSIBLY REMAINING RAIN-FREE. WITH THE LOSS OF DIURNAL HEATING ALL CONVECTION WILL DISSIPATE BY MID-EVENING OR SO. THE COOLER ONSHORE FLOW SHOULD ONLY ALLOW TEMPERATURES TO REACH HIGHS IN THE UPPER 80S TO AROUND 90 INLAND AWAY FROM THE COAST. LOWS TUESDAY NIGHT WILL ACTUALLY BE UNSEASONABLY COOL...IN THE UPPER 60S TO LOWER 70S. WEDNESDAY AND WEDNESDAY NIGHT...A WEAK SHORT WAVE DISTURBANCE WILL PASS MAINLY NORTH OF THE AREA ON WEDNESDAY...BUT CAUSE SOME WEAKNESS ALONG THE EASTERN PERIPHERY OF THE MID AND UPPER LEVEL RIDGE. AT THE SURFACE...HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTHEAST AS THE STALLED FRONT TO THE SOUTH DISSIPATES. DESPITE THE PASSAGE OF THE DISTURBANCE...MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING LITTLE IN THE WAY OF CONVECTION OVER THE AREA. THE FORECAST WILL INDICATE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER SOUTHEAST GEORGIA AND FAR SOUTHERN SOUTH CAROLINA DURING THE AFTERNOON...MAINLY BECAUSE THE DEEPEST MOISTURE WILL REMAIN OVER THESE AREAS. DAYTIME HIGHS WILL REMAIN IN THE UPPER 80S TO AROUND 90...WITH LOWS WEDNESDAY NIGHT AROUND 70 OR IN THE LOWER 70S INLAND FROM THE BEACHES. THURSDAY...THE MID AND UPPER LEVEL RIDGE WILL EXPAND AND BECOME WEST-EAST ORIENTED OVER THE REGION AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WESTERN ATLANTIC. THIS IS A MORE TYPICAL SUMMERTIME PATTERN...WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO OCCUR ALONG AND AHEAD OF THE SEA BREEZE IN THE AFTERNOON AND EARLY EVENING. TEMPERATURES WILL WARM AS THE FLOW BECOMES MORE SOUTHERLY...WITH HIGHS IN THE LOWER 90S AWAY FROM THE COAST. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH MOST OF THE LONG TERM PERIOD...LEADING TO A HIGHER THAN NORMAL CONFIDENCE FORECAST. AN EXPANSIVE UPPER LEVEL RIDGE WILL PREVAIL OVER THE REGION THROUGH SATURDAY...BEFORE A LONG WAVE TROUGH EXPANDS ACROSS THE EASTERN U.S. LATE IN THE WEEKEND INTO EARLY NEXT WEEK. AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL PREVAIL INTO THE WEEKEND...THEN A BACKDOOR COLD FRONT APPEARS POISED TO AFFECT THE AREA LATE SUNDAY AND MONDAY. CONVECTION WILL BE DIURNALLY DRIVEN THROUGH SATURDAY...WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED ALONG AND AHEAD OF THE SEA BREEZE EACH AFTERNOON AND EARLY EVENING. THE PROBABILITY OF SHOWERS AND THUNDERSTORMS SHOULD INCREASE LATE IN THE WEEKEND INTO EARLY NEXT WEEK IN ASSOCIATION WITH THE BACKDOOR COLD FRONT. TEMPERATURES SHOULD BE NEAR NORMAL THROUGH MOST OF THE LONG TERM...WITH THE WARMEST TEMPERATURES LIKELY COMING SATURDAY WITH SOME COMPRESSIONAL HEATING AHEAD OF THE FRONT. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... MOSTLY VFR CONDITIONS EXPECTED THROUGH 12Z TUESDAY AT BOTH KCHS AND KSAV. ISOLATED SHOWERS AND THUNDERSTORMS COULD IMPACT THE TERMINALS...ESPECIALLY AT KSAV...BUT WOULD LIKELY BE BRIEF AND CONFIDENCE IS NOT HIGH ENOUGH TO MENTION AT THIS TIME. EASTERLY WINDS WILL INCREASE UPWARDS OF AROUND 15 KT THIS AFTERNOON...MAINLY AT KSAV...WITH A FEW HIGHER GUSTS POSSIBLE AS THE GRADIENT TIGHTENS OVER THE AREA. SOME LOWER CEILINGS ARE POSSIBLE AT KSAV LATE TONIGHT AS LOW LEVEL MOISTURE POOLS IN THE VICINITY OF THE STALLED FRONT TO THE SOUTH...BUT WILL KEEP CONDITIONS VFR UNTIL CONFIDENCE INCREASES. EXTENDED AVIATION OUTLOOK...ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE EACH AFTERNOON/EARLY EVENING AND COULD RESULT IN BRIEF REDUCTIONS IN CEILINGS/VISIBILITIES. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO PREVAIL. && .MARINE... TODAY...A BACKDOOR COLD FRONT NEAR THE SAVANNAH RIVER WILL PUSH SOUTHWARD LEADING TO A SURGE OF EAST/NORTHEAST WINDS...AS HIGH AS 15-20 KT AT TIMES OVER THE SC WATERS. SEAS WILL RESPOND A BIT AS WELL BUT SHOULD STAY 4 FT OR LESS...HIGHEST OFFSHORE. THUS...NO ADVISORIES ARE EXPECTED. TONIGHT...MAINLY EAST WINDS EXPECTED AOB 15 KT AS HIGH PRESSURE REMAINS NORTH OF THE AREA WITH LOW PRESSURE TO THE SOUTH. TUESDAY THROUGH SATURDAY...A BACKDOOR COLD FRONT WILL STALL JUST SOUTH OF THE WATERS INTO WEDNESDAY BEFORE DISSIPATING...MAINTAINING AN ONSHORE FLOW ACROSS THE WATERS. THE FLOW WILL VEER SOUTHERLY LATER IN THE WEEK AS HIGH PRESSURE BUILDS IN FROM THE WESTERN ATLANTIC. IN GENERAL...WINDS SHOULD REMAIN AT OR BELOW 15 KT...HIGHEST NEAR SEABREEZE CIRCULATIONS ALONG THE COAST. SEAS WILL RANGE BETWEEN 1-3 FT...HIGHEST OVER OUTER GEORGIA WATERS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
240 PM CDT MON AUG 5 2013 .DISCUSSION... 1135 AM CDT NEAR TERM FOCUS REMAINS ON SHRA/TSRA POTENTIAL THROUGH THE REST OF THE DAY. WATER VAPOR IMAGERY SHOWS ONCE SHORTWAVE CROSSING THE LOCAL AREA LATE THIS MORNING WITH THE REMNANTS OF AN MCS MOVING SOUTHEASTWARD WITH IT. THE SOUTHWEST FLANK OF THIS ACTIVITY HAS REMAINED ACTIVE IN TERMS OF MAINTENANCE/REGENERATION OF REFLECTIVITY...AS WELL AS SOME THUNDER...AS IT MOVES FROM SOUTHWESTERN BUREAU COUNTY SOUTHEAST. WITH MID LEVEL MOISTURE TRANSPORT AIMED INTO THIS AREA SUSPECT THAT THIS BETTER ORGANIZED AREA WILL CONTINUE AND MAINLY MOVE JUST SOUTHWEST OF THE CWA OVER THE NEXT FEW HOURS...THOUGH AREAS FROM WEST OF STREATOR TO PONTIAC DOWN TO SOUTHERN FORD COUNTY MAY BE GRAZED BY SOME HEAVIER SHOWERS AND POSSIBLY SOME THUNDER. OTHERWISE EXPECT THE CURRENT AREA OF LIGHT RAIN THE NORTH NORTHEAST OF THE BETTER REFLECTIVITY TO FESTER AS IT MOVES SOUTHEASTWARD AS WELL SO SOME LIGHT RAIN WILL REMAIN CONTINUE GENERALLY ALONG AND SOUTH OF I-88 IN ILLINOIS AND EVENTUALLY INTO NW INDIANA INTO EARLY AFTERNOON BUT COVERAGE OF MEASURABLE PRECIP MAY DIMINISH WITH TIME. GOING THROUGH THE REMAINDER OF THE AFTERNOON...ANOTHER SHORTWAVE IS MOVING ACROSS NORTHERN IOWA. AN MCS CONTINUES TO MOVE ACROSS WESTERN IOWA WITH A SOUTHEAST TRAJECTORY WITH ANOTHER AREA OF SCATTERED CONVECTION BETWEEN MASON CITY AND DECORAH WHICH HAS A MORE EASTERLY MOVEMENT. THE FORCING DRIVING THIS WILL CROSS THE AREA MID TO LATE AFTERNOON AND MUCH OF THIS ACTIVITY MAY REMAIN JUST TO THE NORTH. THE CLOUD SHIELD REMAINS EXTENSIVE ACROSS THE AREA THIS MORNING WHICH HAS TEMPERED WARMING BUT THERE AREA GAPS IN COVERAGE BEHIND THE RAIN CURRENTLY CROSSING THE AREA. THIS MAY ALLOW FOR A CORRIDOR OF DESTABILIZATION ACROSS THE NORTHERN CWA WHICH MAY PROMOTE SOME ADDITIONAL SCATTERED ACTIVITY AS THE NEXT WAVE MOVES THROUGH. STRONG/SEVERE THREAT IS NOT ZERO BUT IS LOW AND VERY CONDITIONAL...HINGING ON POCKETS OF DESTABILIZATION THAT MAY OR MAY NOT MATERIALIZE THIS AFTERNOON. COVERAGE LOOKS SCATTERED SO AM FAVORING HIGH CHANCE POPS ACROSS THE NORTHERN HALF OR SO OF THE AREA FOR THE MID AND LATE AFTERNOON. WITH ANTICIPATION OF MOSTLY CLOUDY SKIES OVER MOST OF THE AREA THROUGH THE AFTERNOON HAVE LOWERED HIGHS A FEW DEGREES FOR MOST AREAS. MDB //PREV DISCUSSION... 355 AM CDT THE PRIMARY FORECAST CONCERN DURING THE PERIOD WILL BE TIMING THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS TODAY INTO TONIGHT...AND AGAIN LATE TUESDAY AND INTO WEDNESDAY. TEMPERATURES WILL ALSO A SIGNIFICANT CONCERN OVER THE NEXT FEW DAYS...AS PRECIP/CLOUD COVER AND FRONTAL TIMING WILL HAVE LARGE IMPACTS ON HOW WARM WE GET. CURRENTLY...ATTENTION IS TURNED TO THE UPPER LEVEL DISTURBANCE MOVING ACROSS NORTH DAKOTA AND INTO MINNESOTA PER WATER VAPOR IMAGERY. THIS FEATURE IS ALREADY INDUCING DECENT LOWER LEVEL SOUTHERLY FLOW AND GOOD MOISTURE RETURN ACROSS THE UPPER MIDWEST. KOAX 00 UTC RAOB FROM SUNDAY EVENING INDICATED A 1.6 INCH PWAT...AND THIS DEEPER MOISTURE IS CONTINUING TO OVERSPREAD MUCH OF THE MID AND UPPER MISSISSIPPI VALLEY AHEAD OF THIS UPPER LEVEL WAVE. SHOWER AND THUNDERSTORM ACTIVITY HAS DEVELOPED ACROSS SOUTHERN PORTIONS OF MINNESOTA JUST AHEAD OF THE AREA OF BEST MOISTURE TRANSPORT. THIS ACTIVITY IS EXPECTED TO SHIFT EAST-SOUTHEASTWARD ACROSS SOUTHERN WISCONSIN THROUGH THE MORNING AND INTO THE AFTERNOON HOURS. IT APPEARS THAT THE BEST FOCUS FOR ACTIVITY WILL BE IN SOUTHERN WISCONSIN...BUT SOME ACTIVITY WILL LIKELY GET INTO FAR NORTHERN ILLINOIS BY THIS AFTERNOON. THEREFORE...I HAVE CONTINUED TO FOCUS THE HIGHEST POPS FAR NORTH. ADDITIONAL THUNDERSTORM ACTIVITY COULD ALSO DEVELOP THIS AFTERNOON TO THE SOUTH AND WEST OF THE MAIN BATCH OF SHOWERS AND STORMS ACROSS SOUTHERN WISCONSIN AND FAR NORTHERN ILLINOIS. IT APPEARS THAT A WEAK SURFACE BOUNDARY...POSSIBLY THE OUTFLOW FROM THE NORTHERN ACTIVITY...COULD FOCUS THIS ADDITIONAL ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND EVENING ACROSS NORTHWESTERN AND POSSIBLY NORTH CENTRAL ILLINOIS. CONFIDENCE IN THE EXTENT OF THIS ADDITIONAL STORM DEVELOPMENT IS LOW AT THIS TIME. HOWEVER...IF THIS ACTIVITY DOES DEVELOP WITHIN THIS INCREASINGLY MOIST/UNSTABLE BOUNDARY LAYER...THESE STORMS COULD HAVE A STRONG TO SEVERE THREAT GIVEN THE STRENGTH OF THE DEEP LAYER SHEAR. THIS WILL HAVE TO BE MONITORED THROUGH THE DAY. IT APPEARS A STRONG TO SEVERE THREAT WOULD REMAIN ACROSS MY WESTERN AREAS...NAMELY NORTH CENTRAL ILLINOIS AND POINTS WEST THIS AFTERNOON. THIS ACTIVITY LOOKS TO CONTINUE INTO THE EVENING ACROSS MUCH OF NORTHERN ILLINOIS. AREAS ACROSS NORTHERN ILLINOIS COULD RECEIVE SOME DECENT RAINFALL AMOUNTS OUT OF THIS ACTIVITY. TEMPERATURES TODAY WILL BE TRICKY AS A RESULT OF THIS CLOUD COVER/PRECIPITATION. CURRENT THINKING IS THAT AREAS ALONG AND SOUTH OF INTERSTATE 80 COULD APPROACH THE LOW 80S THIS AFTERNOON...AS THE THREAT FOR PRECIP WILL BE MUCH LOWER THERE. HOWEVER...TO THE NORTH OF THIS...THE FLOW OFF THE LAKE...ALONG WITH MORE THICK CLOUD COVER AND PRECIP WILL LIKELY KEEP THINGS COOLER...ESPECIALLY ACROSS THE FAR NORTH...WERE TEMPERATURES MAY ONLY TOP OUT AROUND 70. ON TUESDAY...THINGS LOOK TO WARM NICELY. TEMPERATURES AT 850 AND 925 MB CONTINUE TO SUGGEST THE MID TO POSSIBLY UPPER 80S FOR DAYTIME HIGHS. THE THREAT FOR WIDESPREAD CONVECTION DURING THE DAY ALSO STILL APPEARS TO BE SOMEWHAT LIMITED...WITH THE POTENTIAL FOR SOME WEAK CAPPING...AND WITH WHAT APPEARS TO BE A DEARTH OF LARGE SCALE FORCING. WITH THIS IN MIND I CONTINUED WITH SLIGHT CHANCE POPS DURING THE DAY...AS ANY DEVELOPMENT WOULD LIKELY BE OF LOW AERIAL COVERAGE. TUESDAY NIGHT AND INTO WEDNESDAY MORNING STILL APPEARS TO BE THE MAIN SHOW. THE MODELS CONTINUE IN GOOD AGREEMENT WITH DIGGING A SIGNIFICANT UPPER LEVEL LOW FROM OVER THE HUDSON BAY...TO THE NORTH CENTRAL CONUS INTO WEDNESDAY. AS THIS OCCURS...THE MODELS ARE INSISTING THAT A A SERIES OF SHORT WAVES ACROSS THE PACIFIC NORTHWEST...WILL BE INGESTED INTO THE STRONG WESTERLIES ACROSS THE NORTHERN CONUS. ALTHOUGH THERE CONTINUES TO BE SOME UNCERTAINTY WITH THE EXTEND OF THUNDERSTORM DEVELOPMENT ACROSS NORTHERN ILLINOIS TUESDAY NIGHT...IT DOES APPEAR THE ASSOCIATED COLD FRONT FROM THIS SYSTEM WILL PUSH ACROSS THE AREA ON WEDNESDAY MORNING/EARLY AFTERNOON. GIVEN THE VERY HIGH THETA E AIR MASS...WITH 1.9+ PWATS...THAT WILL BE IN PLACE WITHIN THE WARM SECTOR OF THIS STORM...A PERIOD OF HEAVY RAINFALL IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY. THERE COULD ALSO BE A SEVERE THREAT WITH THIS ACTIVITY. THE TIME OF DAY DOES NOT APPEAR TO BE THE MOST FAVORABLE FOR SEVERE STORMS...BUT WITH A MODERATELY UNSTABLE ENVIRONMENT AND DECENT DEEP LAYER SHEAR...THERE IS AT LEAST A CONDITIONAL THREAT FOR SEVERE THUNDERSTORMS PRIOR TO THE FRONTAL PASSAGE WEDNESDAY. THE SURFACE COLD FRONT WILL BRING AN END TO THE THREAT FOR CONVECTION FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA ON WEDNESDAY. IT APPEARS ALTHOUGH COOL AIR WILL BEGIN FILTER IN ACROSS THE AREA DURING THE DAY...TEMPERATURES COULD ONE AGAIN TOP OUT INTO THE 80S BEFORE THE COOLER AIR ARRIVES. SLIGHTLY COOLER AND DRIER WILL AGAIN MAKE A RETURN TO THE AREA FOR A PERIOD LATER IN THE WEEK. HOWEVER...IT APPEARS THE STRONG WESTERLY UPPER FLOW PATTERN COULD DRIVE A FEW ADDITIONAL DISTURBANCES ACROSS CENTRAL ILLINOIS LATER IN THE WEEK. THIS ACTIVITY LOOKS TO LARGELY REMAIN SOUTH OF THE AREA...BUT I DID PUT SOME SLIGHT CHANCE POPS IN FAR SOUTH TO ACCOUNT FOR THIS POSSIBILITY. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * AREA OF -RA CONTINUING TO MOVES SE AWAY FROM CHI AREA EARLY THIS AFTERNOON. * ADDITIONAL SHOWERS LATE AFTERNOON THROUGH MID EVENING WITH MVFR VISIBILITY IN HEAVIER SHOWERS. * ISOLD TS WITHIN AREA OF SHOWERS LATE AFTERNOON INTO EARLY EVENING. * PREVAILING MVFR CONDITIONS DUE VISIBILITY AND CEILINGS DEVELOPING LATE EVENING-OVERNIGHT. //DISCUSSION...UPDATED 18Z... AREA OF -RA COVERAGE CONTINUES TO TO MOVE SE OUT OF N CENTRAL AND NE IL AT MIDDAY. AREA OF OVER THE NE-IA BORDER SHOWED A STRENGTHENING TREND DURING THE MID-LATE MORNING...THOUGH NOW WEAKENING AS OF MIDDAY. MEANWHILE...CONVECTION IN FAR NE IA HAS SHOWN SLOW GROWTH/STRENGTHENING A STRONG JET MAX CONTINUES TO ADVANCE FROM THE EASTERN DAKOTAS ACROSS CENTRAL AND SOUTHERN MN. 925-850HPA THETA E ADVECTION AND CONVERGENCE HIGHLIGHT SOUTHERN WI AND NORTHERN IL FOR CONTINUED CONVECTIVE DEVELOPMENT INTO THE LOCAL AREA MID-LATE AFTERNOON AS A SHORT WAVE TROUGH MOVES TO SE WI AN N CENTRAL IL BY 06.00Z. PARTIAL CLEARING ACROSS SOUTHERN WI AND FAR NORTHERN IL WILL ALLOW DESTABILIZATION AND PROMOTE FURTHER CONVECTIVE DEVELOPMENT DUE TO SURFACE HEATING...THOUGH ONLY EXPECT ISOLD TO WIDELY SCT TS AS WHILE THIS SURFACE HEATING IS OCCURRING BACKING AND INCREASING LOWER AND MID LEVEL FLOW WARMS THESE LEVELS COUNTERING THE DESTABILIZATION FROM THE SURFACE HEATING. LATE THIS EVENING THROUGH DAWN LOW LEVEL MOISTURE WILL BE ABUNDANT AND TRAPPED UNDER AN INVERSION WITH A TOP AROUND 950HPA...WHILE SURFACE WINDS BECOME LIGHT. EXPECT MVFR CONDITIONS TO DEVELOP OVERNIGHT...WITH LOCAL AREAS OF IFR TIL 1-2HR AFTER SUNRISE. TRS //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONTINUED VFR THROUGH MID AFTERNOON. * MEDIUM FOR SHRA AND ISOLD TS LATER AFTERNOON-EARLY EVENING. * MEDIUM FOR LOCAL MVFR WITH LATER AFTERNOON-EARLY EVENING SHRA. * MEDIUM OM MVFR CIGS/VSBYS DEVELOPING LATER EVENING AND PERSISTING INTO MID TUE MORNING...WITH LOCAL IFR. TRS //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...TSRA LIKELY WITH POSSIBLY BRIEF MVFR/IFR. WEDNESDAY...CHC OF TSRA MAINLY IN THE MORNING. THURSDAY-SUNDAY...VFR LIKELY. MTF && .MARINE... 240 PM...A BROAD WEAK TROUGH EXTENDING ACROSS THE PLAINS FROM A SLIGHTLY STRONGER LOW OVER ONTARIO WILL SLOWLY MOVE EAST ACROSS THE WESTERN LAKES WEDNESDAY...WITH THE LOW OVER ONTARIO SLOWLY MOVING EAST THROUGH MID WEEK. AHEAD OF THIS TROUGH...SOUTHERLY WINDS HAVE INCREASED TO 10-20 KT AND FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR SOME WINDS INTO THE 15-25 KT RANGE THIS EVENING BEFORE SLOWLY DIMINISHING OVERNIGHT. ONCE THE TROUGH/COLD FRONT MOVES ACROSS THE LAKE MIDDAY WEDNESDAY...WINDS WILL SHIFT NORTHERLY WITH A PERIOD OF 10-20 KTS POSSIBLE BUT APPEARS THAT WOULD BE SHORT LIVED AS HIGH PRESSURE SPREADS ACROSS THE LAKES REGION WEDNESDAY NIGHT INTO THURSDAY. THE LOW OVER ONTARIO FINALLY SHIFTS EAST INTO QUEBEC ON FRIDAY...WITH A WEAK COLD FRONT MOVING ACROSS THE WESTERN LAKES FRIDAY NIGHT SHIFTING WINDS BACK NORTHERLY INTO SATURDAY WITH ANOTHER HIGH MOVING ACROSS THE LAKES SATURDAY NIGHT INTO SUNDAY. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 233 PM CDT Mon Aug 5 2013 .DISCUSSION... ISSUED 230 PM CDT Mon Aug 5 2013 Remnants of morning thunderstorm cluster have been skirting the northern part of the forecast area over the last few hours, producing a quarter to half inch of rain near Lacon. The southern MCS has remained well away from us, with just extensive cloud cover in between the two systems. These clouds have kept most areas in the mid to upper 70s as of early afternoon, with some lower 80s occurring in the far eastern CWA where there has been more sunshine today. SHORT TERM...Tonight through Friday... Have largely rain chances from the forecast through early Tuesday, as latest models suggest a similar pattern as to last night, with two convective complexes and our forecast area in between. Rain chances should begin increasing from the southwest by Tuesday afternoon as the remnants of the morning convection creep toward us. A shortwave, current evident on water vapor imagery just north of Montana, will deepen as it swings southeast across the northern tier of states over the next couple days. Associated frontal boundary still on track to sweep across the forecast area Wednesday morning and be past us early in the afternoon. Highest rain chances remain concentrated around this front, although late night timing does not favor significant severe weather chances. Latest SPC convective outlooks only give 5% chances of severe weather Tuesday night over the entire area, and similar values ahead of the front Wednesday morning across the southeast CWA. Frontal boundary still progged to hang up to our south Wednesday night as it parallels the upper flow. General model consensus has it extending from the Ohio Valley into southern Missouri, although the GFS is further north toward the I-70 corridor. The models have been continuing their trend of inching the precipitation back northward, with some influence from another trough swinging through the western Great Lakes late in the week. Will increase PoPs to around 60% in the southeast CWA Thursday night. Confidence further north is a little shakier, with the GFS much more aggressive with surface development as the upper trough approaches, but will have rain chances over most of the remaining CWA Thursday night and in the south half on Friday. LONG TERM...Saturday through Monday... General northwest flow expected to amplify a bit through the weekend as ridging re-establishes itself across the Rockies. Most of the Midwest will be under the influence of high pressure into early next week. However, the longer range models show periodic MCS systems once again along the northern periphery of the ridge. The rain chances in the late period grids are mainly focused across the south and southwest CWA, closer to the MCS track. GEELHART && .AVIATION... ISSUED 1256 PM CDT Mon Aug 5 2013 An area of showers will continue to dissipate as it drops southeastward toward KPIA and KBMI over the next 2 to 3 hours. Based on radar trends...will include a tempo group for showers at KPIA between 18z/19z...but will only include VCSH at KBMI. Further southeast...will maintain dry conditions at the remaining central Illinois terminals. A 4000 to 5000ft overcast will remain in place through much of the day...before gradually dissipating by late afternoon/evening. As skies at least partially clear and winds diminish to less than 5kt...patchy fog may become an issue overnight. HRRR shows fog developing across the western KILX CWA toward midnight...and think that trend will spread further eastward overnight. Have hit fog hardest along/west of I-55 where low-level moisture will be most plentiful...with visbys down to 3SM at both KPIA and KSPI late tonight. Further east...have only reduced visbys to around 5SM at KCMI. Winds will initially be from the south at 10 to 15kt this afternoon...then will become light tonight. Southerly winds of around 10kt will resume by Tuesday morning. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
355 AM CDT MON AUG 5 2013 .DISCUSSION... 355 AM CDT THE PRIMARY FORECAST CONCERN DURING THE PERIOD WILL BE TIMING THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS TODAY INTO TONIGHT...AND AGAIN LATE TUESDAY AND INTO WEDNESDAY. TEMPERATURES WILL ALSO A SIGNIFICANT CONCERN OVER THE NEXT FEW DAYS...AS PRECIP/CLOUD COVER AND FRONTAL TIMING WILL HAVE LARGE IMPACTS ON HOW WARM WE GET. CURRENTLY...ATTENTION IS TURNED TO THE UPPER LEVEL DISTURBANCE MOVING ACROSS NORTH DAKOTA AND INTO MINNESOTA PER WATER VAPOR IMAGERY. THIS FEATURE IS ALREADY INDUCING DECENT LOWER LEVEL SOUTHERLY FLOW AND GOOD MOISTURE RETURN ACROSS THE UPPER MIDWEST. KOAX 00 UTC RAOB FROM SUNDAY EVENING INDICATED A 1.6 INCH PWAT...AND THIS DEEPER MOISTURE IS CONTINUING TO OVERSPREAD MUCH OF THE MID AND UPPER MISSISSIPPI VALLEY AHEAD OF THIS UPPER LEVEL WAVE. SHOWER AND THUNDERSTORM ACTIVITY HAS DEVELOPED ACROSS SOUTHERN PORTIONS OF MINNESOTA JUST AHEAD OF THE AREA OF BEST MOISTURE TRANSPORT. THIS ACTIVITY IS EXPECTED TO SHIFT EAST-SOUTHEASTWARD ACROSS SOUTHERN WISCONSIN THROUGH THE MORNING AND INTO THE AFTERNOON HOURS. IT APPEARS THAT THE BEST FOCUS FOR ACTIVITY WILL BE IN SOUTHERN WISCONSIN...BUT SOME ACTIVITY WILL LIKELY GET INTO FAR NORTHERN ILLINOIS BY THIS AFTERNOON. THEREFORE...I HAVE CONTINUED TO FOCUS THE HIGHEST POPS FAR NORTH. ADDITIONAL THUNDERSTORM ACTIVITY COULD ALSO DEVELOP THIS AFTERNOON TO THE SOUTH AND WEST OF THE MAIN BATCH OF SHOWERS AND STORMS ACROSS SOUTHERN WISCONSIN AND FAR NORTHERN ILLINOIS. IT APPEARS THAT A WEAK SURFACE BOUNDARY...POSSIBLY THE OUTFLOW FROM THE NORTHERN ACTIVITY...COULD FOCUS THIS ADDITIONAL ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND EVENING ACROSS NORTHWESTERN AND POSSIBLY NORTH CENTRAL ILLINOIS. CONFIDENCE IN THE EXTENT OF THIS ADDITIONAL STORM DEVELOPMENT IS LOW AT THIS TIME. HOWEVER...IF THIS ACTIVITY DOES DEVELOP WITHIN THIS INCREASINGLY MOIST/UNSTABLE BOUNDARY LAYER...THESE STORMS COULD HAVE A STRONG TO SEVERE THREAT GIVEN THE STRENGTH OF THE DEEP LAYER SHEAR. THIS WILL HAVE TO BE MONITORED THROUGH THE DAY. IT APPEARS A STRONG TO SEVERE THREAT WOULD REMAIN ACROSS MY WESTERN AREAS...NAMELY NORTH CENTRAL ILLINOIS AND POINTS WEST THIS AFTERNOON. THIS ACTIVITY LOOKS TO CONTINUE INTO THE EVENING ACROSS MUCH OF NORTHERN ILLINOIS. AREAS ACROSS NORTHERN ILLINOIS COULD RECEIVE SOME DECENT RAINFALL AMOUNTS OUT OF THIS ACTIVITY. TEMPERATURES TODAY WILL BE TRICKY AS A RESULT OF THIS CLOUD COVER/PRECIPITATION. CURRENT THINKING IS THAT AREAS ALONG AND SOUTH OF INTERSTATE 80 COULD APPROACH THE LOW 80S THIS AFTERNOON...AS THE THREAT FOR PRECIP WILL BE MUCH LOWER THERE. HOWEVER...TO THE NORTH OF THIS...THE FLOW OFF THE LAKE...ALONG WITH MORE THICK CLOUD COVER AND PRECIP WILL LIKELY KEEP THINGS COOLER...ESPECIALLY ACROSS THE FAR NORTH...WERE TEMPERATURES MAY ONLY TOP OUT AROUND 70. ON TUESDAY...THINGS LOOK TO WARM NICELY. TEMPERATURES AT 850 AND 925 MB CONTINUE TO SUGGEST THE MID TO POSSIBLY UPPER 80S FOR DAYTIME HIGHS. THE THREAT FOR WIDESPREAD CONVECTION DURING THE DAY ALSO STILL APPEARS TO BE SOMEWHAT LIMITED...WITH THE POTENTIAL FOR SOME WEAK CAPPING...AND WITH WHAT APPEARS TO BE A DEARTH OF LARGE SCALE FORCING. WITH THIS IN MIND I CONTINUED WITH SLIGHT CHANCE POPS DURING THE DAY...AS ANY DEVELOPMENT WOULD LIKELY BE OF LOW AERIAL COVERAGE. TUESDAY NIGHT AND INTO WEDNESDAY MORNING STILL APPEARS TO BE THE MAIN SHOW. THE MODELS CONTINUE IN GOOD AGREEMENT WITH DIGGING A SIGNIFICANT UPPER LEVEL LOW FROM OVER THE HUDSON BAY...TO THE NORTH CENTRAL CONUS INTO WEDNESDAY. AS THIS OCCURS...THE MODELS ARE INSISTING THAT A A SERIES OF SHORT WAVES ACROSS THE PACIFIC NORTHWEST...WILL BE INGESTED INTO THE STRONG WESTERLIES ACROSS THE NORTHERN CONUS. ALTHOUGH THERE CONTINUES TO BE SOME UNCERTAINTY WITH THE EXTEND OF THUNDERSTORM DEVELOPMENT ACROSS NORTHERN ILLINOIS TUESDAY NIGHT...IT DOES APPEAR THE ASSOCIATED COLD FRONT FROM THIS SYSTEM WILL PUSH ACROSS THE AREA ON WEDNESDAY MORNING/EARLY AFTERNOON. GIVEN THE VERY HIGH THETA E AIRMASS...WITH 1.9+ PWATS...THAT WILL BE IN PLACE WITHIN THE WARM SECTOR OF THIS STORM...A PERIOD OF HEAVY RAINFALL IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY. THERE COULD ALSO BE A SEVERE THREAT WITH THIS ACTIVITY. THE TIME OF DAY DOES NOT APPEAR TO BE THE MOST FAVORABLE FOR SEVERE STORMS...BUT WITH A MODERATELY UNSTABLE ENVIRONMENT AND DECENT DEEP LAYER SHEAR...THERE IS AT LEAST A CONDITIONAL THREAT FOR SEVERE THUNDERSTORMS PRIOR TO THE FRONTAL PASSAGE WEDNESDAY. THE SURFACE COLD FRONT WILL BRING AN END TO THE THREAT FOR CONVECTION FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA ON WEDNESDAY. IT APPEARS ALTHOUGH COOL AIR WILL BEGIN FILTER IN ACROSS THE AREA DURING THE DAY...TEMPERATURES COULD ONE AGAIN TOP OUT INTO THE 80S BEFORE THE COOLER AIR ARRIVES. SLIGHTLY COOLER AND DRIER WILL AGAIN MAKE A RETURN TO THE AREA FOR A PERIOD LATER IN THE WEEK. HOWEVER...IT APPEARS THE STRONG WESTERLY UPPER FLOW PATTERN COULD DRIVE A FEW ADDITIONAL DISTURBANCES ACROSS CENTRAL ILLINOIS LATER IN THE WEEK. THIS ACTIVITY LOOKS TO LARGELY REMAIN SOUTH OF THE AREA...BUT I DID PUT SOME SLIGHT CHANCE POPS IN FAR SOUTH TO ACCOUNT FOR THIS POSSIBILITY. KJB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * SOUTHERLY WINDS POSSIBLY SHIFTING SE OR EVEN ESE FOR A PERIOD DURING THE MID TO LATE AFTERNOON INTO THE EARLY EVE. * INCREASING POTENTIAL FOR SHRA/RA BY AFTERNOON WITH DETERIORATING CIGS/VIS INTO LOW MVFR RANGE LATE IN THE DAY INTO THE EVE. * INITIAL LIMITED COVERAGE OF THUNDERSTORMS INCREASING INTO THE EVE. //DISCUSSION...UPDATED 06Z... HIGH PRESSURE CENTERED ACROSS LOWER MI EARLY THIS MORNING WILL SHIFT EAST AS AN ELONGATED LOW PRESSURE TROUGH DEVELOPS FROM THE UPPER MIDWEST INTO THE WESTERN PLAINS. AN UPPER LEVEL DISTURBANCE WILL RIDE A STRONG JET INTO THE AREA BY LATE MORNING AND INTO THE AFTERNOON...AND THIS IS RESPONSIBLE FOR THE EARLY MORNING STORMS ACROSS MN. IT IS POSSIBLE REMNANTS OF SOME OF THESE STORMS APPROACH THE AREA AS EARLY AS MID-MORNING...BUT THE MOST FAVORED TIME FOR RA/SHRA COVERAGE WILL BE THIS AFTERNOON. THERE IS A STRONG SIGNAL FOR MVFR CIGS...BUT HOW LOW IN THAT CATEGORY VARIES. IF RAIN IS MORE STEADY THEN AROUND 1000 FT IS LIKELY. AS FOR THUNDER...WHILE SOME SCATTERED EMBEDDED THUNDER IS FAVORED IN THE AFTERNOON...THE CHANCES ACTUALLY INCREASE LATE IN THE DAY INTO THE EVE. A SECOND SHORTWAVE...OR AN EXTENSION FROM THE FIRST...MAY TRIGGER SCATTERED STORMS DURING THAT TIME AND THAT IS WHY PROB30S FOR TSRA ARE IN THE TAFS. EVEN IF THESE DEVELOP...THE AMOUNT OF COVERAGE IS HIGHLY UNCERTAIN AT THIS TIME. SOUTHERLY WINDS ARE PREVALENT IN ALL HOURS OF THE TAF...HOWEVER IT IS POSSIBLE FOR A SHIFT TO SE OR ESE FOR FAR NE IL SITES...INCLUDING ORD AND MDW. THIS WOULD BE LIKELY DURING THE LATER AFTERNOON AND DEPENDS IN SOME PART HOW MUCH RAIN COVERAGE THERE IS. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE IN TIMING PRECIPITATION AND ASSOCIATED CIG/VIS TRENDS. LOW CONFIDENCE ON HOW LOW CIGS WILL DROP...BUT LIKELY NEARING AT LEAST 1500 FT IF RAIN OCCURS AS FORECAST. * LOW CONFIDENCE THAT TSRA WILL DIRECTLY IMPACT TERMINALS...MEDIUM CONFIDENCE IN AT LEAST A FEW TSRA IN THE AREA PARTICULARLY LATER TODAY INTO THIS EVE. * LOW CONFIDENCE IN WIND TRENDS AFTER 20Z TODAY. //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY AND WEDNESDAY...CHANCE OF TSRA. PERIODS OF MVFR/IFR CIG/VIS POSSIBLE. THURSDAY THROUGH SATURDAY...VFR. MTF/RATZER && .MARINE... 258 AM CDT AS HIGH PRESSURE MOVES EAST FROM LOWER MI TODAY SOUTHERLY WINDS WILL ENVELOP THE LAKE AS NEARLY STATIONARY LOW PRESSURE EVOLVES OVER MN. THIS WIND WILL LIKELY HAVE A HANDFUL OF GUSTS TO NEAR 25 KT OVER THE OPEN WATER OF THE SOUTH. AS THE LOW PRESSURE TO OUR NORTHWEST EVENTUALLY MOVES TO NEAR ST JAMES BAY WEDNESDAY MORNING...A COOL FRONT IS EXPECTED TO SWING ACROSS THE LAKE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THE COOL AIR ADVECTION IN THE WAKE OF THIS MAY ENABLE SOME 20-25 KT GUSTS ACROSS THE NORTH ON WEDNESDAY. HIGH PRESSURE WILL THEN BUILD IN FOR THURSDAY FOLLOWED BY ANOTHER LIKELY LOW PRESSURE TRANSLATING NORTHEAST INTO CANADA SOMETIME LATE IN THE WEEK. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 330 AM CDT Mon Aug 5 2013 .DISCUSSION... ISSUED 330 AM CDT Mon Aug 5 2013 SHORT TERM...Today through Thursday night Some patchy fog in southeast IL with Effingham, Terre Haute and Mount Carmel Airports having visibilities around 2 miles, should lift by mid morning. 1020 mb high pressure over Ohio and eastern lower Michigan to drift east into the mid Atlantic states by sunset with return sse flow developing over IL and bringing warmer and more humid air into region next few days. Central IL appears to be caught in between two MCS`s today with one over the upper MS valley affecting northeast IL while another MCS over the Ozarks in SW MO to stay sw of central/se IL. So most appears appear to stay dry today and models have trended drier today as well. Will just carry 20% chance of a shower or thunderstorm from I-55 west with best chances over northern 3 counties of Knox, Stark and Marshall late this morning & afternoon which will be on the southern fringe of the northern MCS system. Highs in the lower 80s this afternoon with dewpoints rising into the 60s...so getting more humid then yesterday. Skies becoming partly to mostly cloudy with more sunshine over eastern IL especially near Wabash River. Models continue to keep much of central/se IL dry tonight and will only carry small chances of showers and thunderstorms over mainly areas from I-74 ne. Central IL will continue to be in between two weather systems to our north and sw over MO. Lows tonight in the mid to upper 60s. Have isolated showers and thunderstorms possible Tuesday morning then a 30% chance Tuesday afternoon with warm and humid conditions with temps in the 80s and dewpoints into the lower 70s with southerly flow. Continue likely chances of convection Tuesday night with better chance of MCS to impact region especially by overnight Tue night and SPC has slight chance of severe storms (15%) from Knox county nw into Iowa. A cold front to press southeast through central IL Wednesday and continue a good chance of convection especially from I-72 south. Another warm and humid day Wed with highs in the mid 80s central IL and upper 80s southeast IL where dewpoints 70-75F. Models have trended wetter over area Wed night through Friday especially over southeast IL as frontal boundary becomes quasi stationary south of IL and disturbances tracking eastward along it. LONG TERM...Friday through Sunday night Drier weather to return to region by Friday night into most of this weekend as 1022 mb high pressure settles into the great lakes region. Temps and humidity levels should also be lower during this time frame. 07 && .AVIATION... ISSUED 1110 PM CDT Sun Aug 4 2013 Little change from previous discussion. Except for the 08z-12z time frame where some lower cigs/vsbys will be possible acrs our southern TAF sites, VFR conditions are expected through the remainder of this forecast period (06z Tue). Patches of mid and high level clouds continue to stream southeast into the area late this evening. Larger band of stratocu seen on satellite edging northeast with bases of cigs in the 4000-6000 foot range. In addition, the past few runs of the HRRR model indicating some lower vsbys in fog and even some stratus developing just south of SPI in the 09z-11z time frame. Current temp-dew point spreads suggest the possibility late tonight...after 08z in SPI. Remnants of MCS which passed acrs SE Mo into extreme southern IL continues to track away from area but will have to watch for some stratus and possibly some lower cigs to form on its northern periphery and drift northwest as the boundary layer winds turn more into an east-southeast direction. At this point will keep vsbys around 5 miles and introduce some lower clouds with bases around 1000 feet late tonight and for now keep this threat in SPI. Scattered-broken cigs at 4000-6000 feet will continue during the day as an upper level system pushes to our north. Will continue with VCSH mainly across our northern TAF sites but coverage appears too limited at this time to go with any tempo groups. Surface winds will continue to be light and variable tonight and then swing into a southerly direction on Monday with speeds of 8 to 13 kts. Smith && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1255 AM CDT MON AUG 5 2013 .DISCUSSION... 916 PM CDT EVENING UPDATE: MADE A FEW CHANGES TO FORECAST. BUMPED UP SKY COVER THIS EVENING WITH SHORTWAVE OVERHEAD THAT SHOULD BE OFF TO THE EAST BY OR AFTER MIDNIGHT. THERE HAVE EVEN BEEN A FEW OBS OF SPRINKLES FALLING FROM THE MID DECK BUT DID NOT FEEL THIS WERE WORTH MENTIONING IN UPDATED ZONES. TEMPERATURES HAVE BEEN TRENDING WELL SO ONLY MADE MINOR TWEAKS TO GOING LOW TEMPERATURE FORECAST...MAINLY TO RAISE TEMPERATURES A BIT IN AND NEAR CHICAGO. ALSO REMOVED SLIGHT POP MENTION FROM FAR NORTHERN ILLINOIS TOWARD DAYBREAK AS FORECAST SOUNDINGS SHOW PLENTY OF DRY AIR TO OVERCOME FROM EXPECTED DECAYING MCS THAT WILL ARRIVE TOMORROW. ALSO...THERE IS NO LOW LEVEL JET SUPPORT FOR MOISTURE TRANSPORT...WITH IT BEING FOCUSED OFF TO THE WEST THROUGH THE NIGHT INTO EARLY MONDAY. THUS ALSO TRENDED POPS TO SLOW ARRIVAL OF SHOWERS TOMORROW MORNING. HOWEVER...THERE IS GOOD AGREEMENT AMONGST GUIDANCE ON STRONG 850 MB MOISTURE TRANSPORT PUSHING INTO NORTHERN IL ESPECIALLY DURING THE AFTERNOON THAT SUPPORTS GOING HIGH LIKELY/LOW CATEGORICAL POPS FOR IN GOING FORECAST. VERY LIMITED INSTABILITY ON FORECAST SOUNDINGS WILL LIKELY KEEP THE THUNDER ISOLATED TOMORROW AND EMBEDDED WITHIN THE SHOWER ACTIVITY. RC //PREV DISCUSSION... 257 PM CDT AFTER A WARM AND UNSETTLED START TO THE WEEK...A FRONTAL PASSAGE ON WEDNESDAY WILL USHER IN COOLER AND DRIER AIR FOR THE SECOND HALF OF THE WEEK INTO NEXT WEEKEND. WEATHER FOR THE UPCOMING WEEK WILL BE INFLUENCED BY AN UPPER LEVEL RIDGE ACROSS THE SOUTHERN AND WESTERN CONUS AND AN UPPER LOW FORMING OVER HUDSON BAY AND THEN DIGGING ACROSS MANITOBA...ONTARIO...AND QUEBEC. THE LARGE SCALE INTERACTIONS BETWEEN THESE FEATURES...AND THEIR RELATIVE POSITIONS OVER THE NEXT FEW DAYS...APPEAR TO BE HANDLED IN A SIMILAR MANNER BY VARIOUS DETERMINISTIC MODELS AND THE GFS ENSEMBLE. THAT PROVIDES CONFIDENCE FOR THE OVERALL TRENDS DURING THE WEEK...BUT WITH LOWER LEVELS BEING SOMEWHAT DIFFUSE...THE TIMING AND LOCATION OF SMALLER SCALE FEATURES WILL TAKE SOME WORK TO PIN DOWN. A SHORTWAVE EMBEDDED IN THE BROAD WESTERN CONUS RIDGE HELPED LIGHT UP SEEMINGLY THE ENTIRE HIGH COUNTRY FROM ALBERTA INTO WESTERN MEXICO DURING PEAK HEATING LATE YESTERDAY. TWO DISTINCT AREAS PERSISTED OVERNIGHT INTO EARLY THIS MORNING...ONE FOCUSED OVER KANSAS AND THE OTHER IN THE DAKOTAS. THE SOUTHERN AREA HAS SHOWN A MUCH GREATER ABILITY TO HANG TOGETHER OVER MISSOURI TODAY BY VIRTUE OF ITS ACCESS TO MORE FAVORABLE GULF MOISTURE WRAPPING AROUND THE SOUTHERN EDGE OF A BROAD SURFACE HIGH THAT WAS CENTERED OVER LAKE MICHIGAN AS OF MID DAY BUT IS FORECAST TO MOVE INTO THE OHIO VALLEY BY TOMORROW MORNING. FOR TONIGHT AND MONDAY...THE GFS/ECMWF DEPICT A BROAD SHORTWAVE DEVELOPING OVER NORTHERN MONTANA THIS AFTERNOON IN AN AREA WHERE CIRCULATION IS EVIDENT IN LATEST WV IMAGERY. A CORRESPONDING 850MB TROUGH IS DEPICTED JUST EAST OF THIS AREA. THE UPPER WAVE WILL DROP THROUGH THE DAKOTAS AND APPARENTLY HELP REDEVELOP THE REMNANTS OF THE MIDLEVEL WAVE OVER THE EASTERN DAKOTAS. TOGETHER BOTH OF THESE FEATURES MOVE TOWARD THE LOCAL AREA OVERNIGHT...OVERTAKING THE 850MB TROUGH AND RUNNING AHEAD OF THE BEST MOISTURE AT LOWER LEVELS DUE TO THE LINGERING EFFECTS OF THE SURFACE RIDGE PARKED OVERHEAD TODAY. SO TOMORROW LOOKS TO START DRY ACROSS MOST OF THE FORECAST AREA. SHOWERS AND SOME THUNDERSTORMS LIKELY WILL SPREAD ACROSS AT LEAST THE NORTHERN HALF OF THE CWA BY AFTERNOON...KEEPING TEMPERATURES DOWN...AS THE 850MB TROUGH MOVES OVERHEAD AND LOWER LEVELS FINALLY SATURATE. AS FOR SEVERE STORMS...THE LOCAL AREA IS EXPECTED TO BE UNDER A BROAD AREA OF MARGINALLY FAVORABLE DEEP LAYER SPEED AND DIRECTIONAL SHEAR...BUT THE BETTER CHANCE FOR ORGANIZED STRONG CONVECTION SHOULD BE WEST AND THEN SOUTH OF THE AREA WHERE THE DEEP LAYER SHEAR OVERLAPS THE MORE PRONOUNCED LOW LEVEL INSTABILITY. FOR MONDAY NIGHT AND TUESDAY...A LOSS OF UPPER LEVEL SUPPORT...WEAK RIDGING AT MID AND LOWER LEVELS...AND DRYING FROM SUBSIDENCE ALOFT...ALL WOULD APPEAR UNFAVORABLE FOR THE MAINTENANCE OF SHOWERS PAST MIDNIGHT AND INTO TUESDAY DESPITE PLENTY OF MOISTURE AT THE SURFACE. IT IS HOWEVER POSSIBLE THAT THIS SFC MOISTURE COULD SUPPORT SOME PATCHY FOG EARLY TUESDAY. WITH SOUTH TO SOUTHWESTERLY FLOW ACROSS MOST OF THE AREA...TUESDAY AFTERNOON SHOULD ALSO BE PRETTY WARM AND HUMID...SUPPORTING HEAT INDICIES IN THE 90S FOR SOME LOCATIONS. FOR TUESDAY NIGHT AND WEDNESDAY...TSRA CHANCES AGAIN INCREASE...BUT SO DOES UNCERTAINTY. AS MENTIONED BEFORE...GFS/ECM/NAM/GEM ALL SHOW THE UPPER LOW DROPPING OUT OF HUDSON BAY INTO THE MANITOBA/ONTARIO AREA WHILE THE UPPER RIDGE FLATTENS ACROSS THE SOUTHERN CONUS. SHORTWAVES EMBEDDED IN THE SOMEWHAT ZONAL FLOW BETWEEN THESE FEATURES WILL HAVE ACCESS TO PLENTY OF MOISTURE AT LOW LEVELS...BUT IT IS NOT CLEAR IF SUCH WAVES WILL BE PRESENT OR WHERE EXACTLY THEY WILL TRAVERSE. WILL MAINTAIN HIGH END CHANCE POPS AS IN PREVIOUS FORECAST FOR MOST OF THE AREA TUESDAY NIGHT BUT FAVOR SOUTHERN PORTIONS WITH LOW END LIKELIES WHERE MODELS ARE HINTING AT A MORE LIKELY SHORTWAVE/MCS TRACK. A REALLY DIFFUSE COLD FRONT THEN CROSSES THE AREA DURING THE DAY WEDNESDAY WITHOUT MUCH LARGE SCALE SUPPORT ALOFT...SO HAVE MAINTAINED CHANCE POPS WITH THE GREATER VALUES EAST OF THIS FEATURE. ALSO HAVE REFLECTED THIS BOUNDARY IN THE MAX TEMP FCST...WITH UPPER 70S TO AROUND 80 NORTH AND MID 80S SOUTH. FOR THURSDAY AND FRIDAY...THE FRONT PUSHING THROUGH WEDNESDAY WILL DRY THINGS OUT AND COOL THE DAYTIME HIGHS THURSDAY AND FRIDAY. WILL MAINTAIN SOME SLIGHT CHANCE POPS FOR SOUTHEASTERN AREAS WEDNESDAY NIGHT TO ACCOUNT FOR UNCERTAINTIES IN TIMING...BUT THEN IGNORE THE GEM AND KEEP PRECIP OUT OF THE FORECAST THROUGH THE END OF THE WORKWEEK. FOR NEXT WEEKEND...COOLER DAYTIME HIGHS PERSIST WITH NORTHERLY FLOW AT THE SURFACE. THE UPPER LOW WILL ALSO CONTINUE ITS SPIN ACROSS THE NORTHERN GREAT LAKES...GENERATING BROAD CYCLONIC FLOW AND PROBABLY SOME WIDESPREAD AFTERNOON CLOUDINESS AND ISOLATED POPUP SHOWERS. OVERALL THERE DOES NOT APPEAR TO BE ENOUGH MOISTURE AT LOW LEVELS TO SUPPORT MENTIONABLE PRECIP AT THIS TIME RANGE. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * SOUTHERLY WINDS POSSIBLY SHIFTING SE OR EVEN ESE FOR A PERIOD DURING THE MID TO LATE AFTERNOON INTO THE EARLY EVE. * INCREASING POTENTIAL FOR SHRA/RA BY AFTERNOON WITH DETERIORATING CIGS/VIS INTO LOW MVFR RANGE LATE IN THE DAY INTO THE EVE. * INITIAL LIMITED COVERAGE OF THUNDERSTORMS INCREASING INTO THE EVE. //DISCUSSION...UPDATED 06Z... HIGH PRESSURE CENTERED ACROSS LOWER MI EARLY THIS MORNING WILL SHIFT EAST AS AN ELONGATED LOW PRESSURE TROUGH DEVELOPS FROM THE UPPER MIDWEST INTO THE WESTERN PLAINS. AN UPPER LEVEL DISTURBANCE WILL RIDE A STRONG JET INTO THE AREA BY LATE MORNING AND INTO THE AFTERNOON...AND THIS IS RESPONSIBLE FOR THE EARLY MORNING STORMS ACROSS MN. IT IS POSSIBLE REMNANTS OF SOME OF THESE STORMS APPROACH THE AREA AS EARLY AS MID-MORNING...BUT THE MOST FAVORED TIME FOR RA/SHRA COVERAGE WILL BE THIS AFTERNOON. THERE IS A STRONG SIGNAL FOR MVFR CIGS...BUT HOW LOW IN THAT CATEGORY VARIES. IF RAIN IS MORE STEADY THEN AROUND 1000 FT IS LIKELY. AS FOR THUNDER...WHILE SOME SCATTERED EMBEDDED THUNDER IS FAVORED IN THE AFTERNOON...THE CHANCES ACTUALLY INCREASE LATE IN THE DAY INTO THE EVE. A SECOND SHORTWAVE...OR AN EXTENSION FROM THE FIRST...MAY TRIGGER SCATTERED STORMS DURING THAT TIME AND THAT IS WHY PROB30S FOR TSRA ARE IN THE TAFS. EVEN IF THESE DEVELOP...THE AMOUNT OF COVERAGE IS HIGHLY UNCERTAIN AT THIS TIME. SOUTHERLY WINDS ARE PREVALENT IN ALL HOURS OF THE TAF...HOWEVER IT IS POSSIBLE FOR A SHIFT TO SE OR ESE FOR FAR NE IL SITES...INCLUDING ORD AND MDW. THIS WOULD BE LIKELY DURING THE LATER AFTERNOON AND DEPENDS IN SOME PART HOW MUCH RAIN COVERAGE THERE IS. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE IN TIMING PRECIPITATION AND ASSOCIATED CIG/VIS TRENDS. LOW CONFIDENCE ON HOW LOW CIGS WILL DROP...BUT LIKELY NEARING AT LEAST 1500 FT IF RAIN OCCURS AS FORECAST. * LOW CONFIDENCE THAT TSRA WILL DIRECTLY IMPACT TERMINALS...MEDIUM CONFIDENCE IN AT LEAST A FEW TSRA IN THE AREA PARTICULARLY LATER TODAY INTO THIS EVE. * LOW CONFIDENCE IN WIND TRENDS AFTER 20Z TODAY. //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY AND WEDNESDAY...CHANCE OF TSRA. PERIODS OF MVFR/IFR CIG/VIS POSSIBLE. THURSDAY THROUGH SATURDAY...VFR. MTF/RATZER && .MARINE... 250 PM CDT WINDS WILL BECOME LIGHT TONIGHT AS HIGH PRESSURE CENTERED OVER NORTHERN WI MOVES SE ACROSS LAKE MI THIS EVENING...AND THEN BECOME SOUTHERLY AND FRESHEN OVERNIGHT AND MONDAY AS THE HIGH MOVES OFF TO OH BY DAWN AND AN AREA OF LOW PRESSURE MOVES SLOWLY E FROM THE NORTHERN AND CENTRAL PLAINS TO THE UPPER MS AND MID MO VALLEYS DURING MONDAY. THIS LOW WEAKENS MONDAY NIGHT AS IT CONTINUES SLOWLY E INTO THE UPPER MIDWEST. ANOTHER LOW WILL MOVE E FROM WI TO MI U.P. TUE. AS THIS LOW MOVES NE INTO ONTARIO WED A COLD FRONT WILL MOVE ACROSS LAKE MI SHIFTING WINDS FROM SOUTHERLY TO OUT OF THE NE AND N AND FRESHEN AS HIGH PRESSURE SLOWLY SETTLES SE FROM THE UPPER MIDWEST AND MID MO VALLEY. THE HIGH MOVES OVER LAKE MI THU...REACHING THE MIDWEST AND MID MS VALLEY LATE THU NIGHT. LOW PRESSURE MOVING E ACROSS ONTARIO WILL MOVE ANOTHER COLD FRONT ACROSS THE LAKE LATE FRI AND FRI NIGHT. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1115 PM CDT Sun Aug 4 2013 .DISCUSSION... ISSUED 845 PM CDT Sun Aug 4 2013 High pressure continues to slowly edge east of our area early this evening. Very pleasant conditions prevail across the region with mild temperatures and comfortable humidities. As the fair weather system continues to move away tonight, our winds will turn more into the south by morning which should allow dew points to rise back into the 60s most of the area by afternoon. Satellite data depicting a rather vigorous shortwave over North Dakaota, which is forecast to track east into the Great Lakes on Monday increasing the chances for showers and thunderstorms, especially across the north. Further to our southwest, another convective complex is expected to form on the nose of the low level jet late tonight and track east and then southeast across parts of southern Missouri. 00Z ILX sounding still indicating quite a bit of dry air in place thanks to the departing area of high pressure with most models holding off any threat for rain until Monday morning at the earliest. Current zone forecast handling the evening trends quite well, so no zone update will be needed. && .AVIATION... ISSUED 1110 PM CDT Sun Aug 4 2013 Little change from previous discussion. Except for the 08z-12z time frame where some lower cigs/vsbys will be possible acrs our southern TAF sites, VFR conditions are expected through the remainder of this forecast period (06z Tue). Patches of mid and high level clouds continue to stream southeast into the area late this evening. Larger band of stratocu seen on satellite edging northeast with bases of cigs in the 4000-6000 foot range. In addition, the past few runs of the HRRR model indicating some lower vsbys in fog and even some stratus developing just south of SPI in the 09z-11z time frame. Current temp-dew point spreads suggest the possibility late tonight...after 08z in SPI. Remnants of MCS which passed acrs SE Mo into extreme southern IL continues to track away from area but will have to watch for some stratus and possibly some lower cigs to form on its northern periphery and drift northwest as the boundary layer winds turn more into an east-southeast direction. At this point will keep vsbys around 5 miles and introduce some lower clouds with bases around 1000 feet late tonight and for now keep this threat in SPI. Scattered-broken cigs at 4000-6000 feet will continue during the day as an upper level system pushes to our north. Will continue with VCSH mainly across our northern TAF sites but coverage appears too limited at this time to go with any tempo groups. Surface winds will continue to be light and variable tonight and then swing into a southerly direction on Monday with speeds of 8 to 13 kts. Smith && .PREV DISCUSSION... ISSUED 250 PM CDT Sun Aug 4 2013 High pressure slowly drifting across the Great Lakes early this afternoon, producing some diurnal cumulus. High clouds continue to stream across the south half of the state, from convection over southwest Missouri that has been on the wane the last few hours. Have had some good mixing of the air aloft which has brought surface dew points down into the lower to mid 50s, as early afternoon air temperatures reached the 75-80 degree range. Aloft, water vapor imagery showing a shortwave tracking along the periphery of an upper high centered over Texas, with the wave moving through eastern Nebraska and western Iowa. A second wave was tracking along the Montana/Saskatchewan border. The primary forecast challenge continues to be with timing of shower and thunderstorm activity the next few days. SHORT TERM...Tonight through Wednesday... Model guidance has generally settled into the thought of producing two separate MCS clusters overnight, one with the Montana wave and tracking to our north, and the other sliding southeast across Missouri in association with the Nebraska wave. Not looking terribly promising in between at the moment, with the best chances of seeing anything in our area being with the northern cluster on Monday into early evening, so have focused most of the rain chances with that feature. Have limited rain chances to slights at best over the remainder of the area into early Tuesday. The main rain maker in our area will be with the primary cold front toward midweek, as a strong upper wave swings across the Great Lakes. Some convective feedback on the GFS is resulting in a slower frontal passage, but the general model consensus a passage through our forecast area late Tuesday night through about midday Wednesday. Will have the highest rain chances over the entire area Tuesday night, and lingering into Wednesday across the southeast quarter. Frontal boundary will not be going through at an optimal time for severe weather, but some stronger winds will be possible with a few of the storms. Greatest potential for heavy rain will be during this period though, as precipitable water values rise to around 2-2.25 inches. LONG TERM...Wednesday night through Sunday... Frontal boundary to slow down Wednesday night as it starts to parallel the upper flow. Latest ECMWF more generous with spreading the rain back northward as ripples of low pressure ride along the boundary, while the GFS keeps most of the precip to our south Wednesday night and Thursday. Have kept some low chances of around 30% across southeast Illinois to account for this. The large upper low which will be spinning over south central Canada much of the week will finally swing eastward late in the week, with an associated frontal boundary sweeping through the state Friday night. With the old boundary south of us intercepting any moisture return, this frontal passage will likely be dry. These dry conditions are expected to linger into next weekend, as high pressure builds southeast into the Midwest. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
254 PM EDT MON AUG 5 2013 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 403 AM EDT MON AUG 5 2013 HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE AREA TODAY AS IT MOVES EASTWARD. VERY WEAK DISTURBANCES IN THE PREVAILING NORTHWEST FLOW ALOFT COULD POTENTIALLY SPARK A SHOWER OR STORM TONIGHT...WITH CHANCES INCREASING TOWARD MIDWEEK AS A FRONTAL SYSTEM APPROACHES FROM THE NORTHWEST AND MOVES THROUGH THE AREA. DRY WEATHER AND COOL TEMPERATURES RETURN ONCE AGAIN FOR THE COMING WEEKEND AS ANOTHER DOME OF HIGH PRESSURE SETTLES OVER THE AREA. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1055 AM EDT MON AUG 5 2013 RADAR MOSAIC SHOWS SHOWERS AND THUNDERSTORMS ACROSS NORTHWEST ILLINOIS THAT ARE HEADED SOUTHEAST. CURRENTLY SATELLITE SHOWS MOSTLY CLEAR SKIES ACROSS MUCH OF THE AREA WITH CLOUDS ACROSS NORTHERN ILLINOIS HEADING SOUTHEAST TOWARD CENTRAL INDIANA. RAP AND HRRR SHOW THE AFOREMENTIONED STORMS EITHER STAYING JUST NORTH OF THE FORECAST AREA OR CLIPPING A FEW OF THE NORTHERN COUNTIES. LOOKING AT THE CURRENT MOVEMENT AND LOCATION OF HIGH SURFACE PRESSURE THINK THERE/S AN OUTSIDE CHANCE STORMS COULD SNEAK INTO THE FAR NORTHERN PARTS OF THE AREA LATE THIS AFTERNOON...SO ADDED A SLIGHT CHANCE FOR THUNDERSTORMS THERE FROM 4 PM ON. GOING HOURLY TEMPERATURES ARE ON TRACK FOR FORECAST HIGHS IN THE LOW 80S SO LEFT THEM ALONE. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 403 AM EDT MON AUG 5 2013 WILL CONTINUE TO CARRY POPS TONIGHT...BUT SLIGHT CHANCE TO LOW CHANCE AT BEST AS SUPPORT IS WEAK. MODELS HAVE EVEN BACKED OFF OF POTENTIAL FOR TUESDAY...BUT WITH BUFKIT SHOWING SOME MODEST CONVECTIVE INSTABILITY WILL CARRY A 30 POP FOR THUNDERSTORMS. HIGHER POPS REMAIN MERITED...BUT CANNOT GO LIKELY ANY PERIOD OWING TO CONTINUED DIFFERENCES BETWEEN MODELS AND RUN TO RUN INCONSISTENCIES WITH THE RELATIVELY WEAK DISTURBANCES MOVING THROUGH THE AREA. HIGHEST POPS WILL OF COURSE BE WITH THE POTENTIAL FRONT MOVING INTO THE AREA MIDWEEK. ON TEMPS...NEAR TO JUST ABOVE CONSENSUS NUMBERS APPEARS TO FIT BEST WITH 850 TEMP TRENDS ACROSS THE BOARD. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... ISSUED AT 254 PM EDT MON AUG 5 2013 FRONTAL BOUNDARY WILL REMAIN NEARLY STATIONARY ACROSS THE OHIO VALLEY THROUGH FRIDAY WITH A CONTINUED THREAT FOR SCATTERED STORMS AS SURFACE WAVES RIPPLE ALONG THE BOUNDARY. WILL CARRY HIGHEST POPS ACROSS SOUTHERN COUNTIES IN CLOSEST PROXIMITY TO THE EXPECTED LOCATION OF THE FRONT. THE ARRIVAL OF A SECONDARY FRONT DROPPING THROUGH THE REGION FRIDAY NIGHT AND SATURDAY MORNING WILL FINALLY PUSH THE REMNANT BOUNDARY WELL SOUTH OF THE FORECAST AREA. HIGH PRESSURE WILL EXPAND INTO THE REGION...BRINGING COOLER AND MUCH DRIER WEATHER TO CENTRAL INDIANA THROUGH THE WEEKEND. MODEL GUIDANCE NOW HINTING THAT UNSETTLED WEATHER LIKELY TO RETURN FOR EARLY NEXT WEEK AS A WARM FRONT LIFTS NORTH INTO THE REGION ON THE BACK SIDE OF HIGH PRESSURE. WILL INTRODUCE LOW CHANCE POPS ON MONDAY. BUMPED HIGH TEMPS UP A FEW DEGREES FROM ALLBLEND FOR FRIDAY... ESPECIALLY ACROSS THE SOUTH...WITH THE BOUNDARY STILL ACROSS THE REGION. HIGHS WILL FALL BACK INTO THE UPPER 70S AND LOWER 80S FOR THE REMAINDER OF THE LONG TERM. && .AVIATION /DISCUSSION FOR 051800Z TAF ISSUANCE/... ISSUED AT 121 PM EDT MON AUG 5 2013 MVFR CONDITIONS POSSIBLE LATE TONIGHT AND TUESDAY MORNING... ESPECIALLY AT KHUF AND KLAF. INITIAL FOCUS FOR THE FORECAST IS AREA OF SLOWLY WEAKENING SHOWERS PROGRESSING SOUTHEAST ACROSS NORTHERN ILLINOIS. NONE OF THE MODELS CURRENTLY HANDLING THIS AREA OF PRECIP WELL AT ALL. THE AREA OF SHOWERS SHOULD CONTINUE TO WEAKEN OVER THE NEXT FEW HOURS AS VERY LITTLE INSTABILITY PRESENT OVER THE REGION. LIGHT SHOWERS HOWEVER MAY MAKE IT TO KLAF BEFORE COMPLETELY DIMINISHING...AND WILL INTRODUCE A VCSH AT THAT TERMINAL FOR THE NEXT FEW HOURS TO COVER. OUTSIDE OF THE AREA OF PRECIP...MID LEVEL CLOUDS WILL STEADILY EXPAND AND LOWER ACROSS THE FORECAST AREA INTO THE EVENING AS A SERIES OF DISTURBANCES ALOFT DRIFT THROUGH THE AREA. POTENTIAL FOR ADDITIONAL CONVECTIVE DEVELOPMENT INTO TONIGHT...ESPECIALLY OVER NORTHERN PARTS OF CENTRAL INDIANA IN CLOSER PROXIMITY TO THE UPPER FORCING TRACKING THROUGH THE GREAT LAKES. HOWEVER WITH VERY LOW CONFIDENCE IN COVERAGE AND TIMING OF ANY DEVELOPMENT...WILL KEEP FORECAST DRY FOR TONIGHT. DESPITE THE INCREASING CLOUD COVER OVERNIGHT...COMBINATION OF LIGHT SOUTHERLY FLOW AND ADDITIONAL LOW LEVEL MOISTURE WILL PRODUCE POTENTIAL FOR MVFR VISIBILITIES TO DEVELOP TOWARDS DAYBREAK TUESDAY...ESPECIALLY AT KHUF AND KLAF. MODEL SOUNDINGS AND RH PROGS SUGGESTIVE OF INCREASING POTENTIAL FOR MVFR STRATOCU TO ADVECT INTO THE REGION TUESDAY MORNING AS AN UPPER LEVEL WAVE TRACKS INTO THE MID MISSISSIPPI VALLEY BY TUESDAY AFTERNOON. LIGHT S/SW FLOW WILL BE LESS THAN 10KTS THROUGH THE END OF THE FORECAST PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...NIELD NEAR TERM...CP SHORT TERM...NIELD LONG TERM....RYAN AVIATION...RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
121 PM EDT MON AUG 5 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 403 AM EDT MON AUG 5 2013 HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE AREA TODAY AS IT MOVES EASTWARD. VERY WEAK DISTURBANCES IN THE PREVAILING NORTHWEST FLOW ALOFT COULD POTENTIALLY SPARK A SHOWER OR STORM TONIGHT...WITH CHANCES INCREASING TOWARD MIDWEEK AS A FRONTAL SYSTEM APPROACHES FROM THE NORTHWEST AND MOVES THROUGH THE AREA. DRY WEATHER AND COOL TEMPERATURES RETURN ONCE AGAIN FOR THE COMING WEEKEND AS ANOTHER DOME OF HIGH PRESSURE SETTLES OVER THE AREA. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1055 AM EDT MON AUG 5 2013 RADAR MOSAIC SHOWS SHOWERS AND THUNDERSTORMS ACROSS NORTHWEST ILLINOIS THAT ARE HEADED SOUTHEAST. CURRENTLY SATELLITE SHOWS MOSTLY CLEAR SKIES ACROSS MUCH OF THE AREA WITH CLOUDS ACROSS NORTHERN ILLINOIS HEADING SOUTHEAST TOWARD CENTRAL INDIANA. RAP AND HRRR SHOW THE AFOREMENTIONED STORMS EITHER STAYING JUST NORTH OF THE FORECAST AREA OR CLIPPING A FEW OF THE NORTHERN COUNTIES. LOOKING AT THE CURRENT MOVEMENT AND LOCATION OF HIGH SURFACE PRESSURE THINK THERE/S AN OUTSIDE CHANCE STORMS COULD SNEAK INTO THE FAR NORTHERN PARTS OF THE AREA LATE THIS AFTERNOON...SO ADDED A SLIGHT CHANCE FOR THUNDERSTORMS THERE FROM 4 PM ON. GOING HOURLY TEMPERATURES ARE ON TRACK FOR FORECAST HIGHS IN THE LOW 80S SO LEFT THEM ALONE. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 403 AM EDT MON AUG 5 2013 WILL CONTINUE TO CARRY POPS TONIGHT...BUT SLIGHT CHANCE TO LOW CHANCE AT BEST AS SUPPORT IS WEAK. MODELS HAVE EVEN BACKED OFF OF POTENTIAL FOR TUESDAY...BUT WITH BUFKIT SHOWING SOME MODEST CONVECTIVE INSTABILITY WILL CARRY A 30 POP FOR THUNDERSTORMS. HIGHER POPS REMAIN MERITED...BUT CANNOT GO LIKELY ANY PERIOD OWING TO CONTINUED DIFFERENCES BETWEEN MODELS AND RUN TO RUN INCONSISTENCIES WITH THE RELATIVELY WEAK DISTURBANCES MOVING THROUGH THE AREA. HIGHEST POPS WILL OF COURSE BE WITH THE POTENTIAL FRONT MOVING INTO THE AREA MIDWEEK. ON TEMPS...NEAR TO JUST ABOVE CONSENSUS NUMBERS APPEARS TO FIT BEST WITH 850 TEMP TRENDS ACROSS THE BOARD. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 249 AM EDT MON AUG 5 2013 ECMWF AND GFS CONTINUE TO INDICATE A COOL NORTHWEST FLOW ALOFT WITH FEW TO NO SHORT WAVE DISTURBANCES PASSING THROUGH THE FLOW INTO THE OHIO VALLEY. AT THE SURFACE A WEAK COLD FRONT IS EXPECTED TO BE PUSHING THROUGH AND EXITING THE AREA ON THURSDAY AND FRIDAY. BY FRIDAY AFTERNOON STRONG SURFACE HIGH PRESSURE LOOKS TO BE IN PLACE PROVING ANOTHER DRY WEEKEND WITH ANOTHER ROUND OF BELOW NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR 051800Z TAF ISSUANCE/... ISSUED AT 121 PM EDT MON AUG 5 2013 MVFR CONDITIONS POSSIBLE LATE TONIGHT AND TUESDAY MORNING... ESPECIALLY AT KHUF AND KLAF. INITIAL FOCUS FOR THE FORECAST IS AREA OF SLOWLY WEAKENING SHOWERS PROGRESSING SOUTHEAST ACROSS NORTHERN ILLINOIS. NONE OF THE MODELS CURRENTLY HANDLING THIS AREA OF PRECIP WELL AT ALL. THE AREA OF SHOWERS SHOULD CONTINUE TO WEAKEN OVER THE NEXT FEW HOURS AS VERY LITTLE INSTABILITY PRESENT OVER THE REGION. LIGHT SHOWERS HOWEVER MAY MAKE IT TO KLAF BEFORE COMPLETELY DIMINISHING...AND WILL INTRODUCE A VCSH AT THAT TERMINAL FOR THE NEXT FEW HOURS TO COVER. OUTSIDE OF THE AREA OF PRECIP...MID LEVEL CLOUDS WILL STEADILY EXPAND AND LOWER ACROSS THE FORECAST AREA INTO THE EVENING AS A SERIES OF DISTURBANCES ALOFT DRIFT THROUGH THE AREA. POTENTIAL FOR ADDITIONAL CONVECTIVE DEVELOPMENT INTO TONIGHT...ESPECIALLY OVER NORTHERN PARTS OF CENTRAL INDIANA IN CLOSER PROXIMITY TO THE UPPER FORCING TRACKING THROUGH THE GREAT LAKES. HOWEVER WITH VERY LOW CONFIDENCE IN COVERAGE AND TIMING OF ANY DEVELOPMENT...WILL KEEP FORECAST DRY FOR TONIGHT. DESPITE THE INCREASING CLOUD COVER OVERNIGHT...COMBINATION OF LIGHT SOUTHERLY FLOW AND ADDITIONAL LOW LEVEL MOISTURE WILL PRODUCE POTENTIAL FOR MVFR VISIBILITIES TO DEVELOP TOWARDS DAYBREAK TUESDAY...ESPECIALLY AT KHUF AND KLAF. MODEL SOUNDINGS AND RH PROGS SUGGESTIVE OF INCREASING POTENTIAL FOR MVFR STRATOCU TO ADVECT INTO THE REGION TUESDAY MORNING AS AN UPPER LEVEL WAVE TRACKS INTO THE MID MISSISSIPPI VALLEY BY TUESDAY AFTERNOON. LIGHT S/SW FLOW WILL BE LESS THAN 10KTS THROUGH THE END OF THE FORECAST PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...NIELD NEAR TERM...CP SHORT TERM...NIELD LONG TERM....PUMA AVIATION...RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1055 AM EDT MON AUG 5 2013 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 403 AM EDT MON AUG 5 2013 HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE AREA TODAY AS IT MOVES EASTWARD. VERY WEAK DISTURBANCES IN THE PREVAILING NORTHWEST FLOW ALOFT COULD POTENTIALLY SPARK A SHOWER OR STORM TONIGHT...WITH CHANCES INCREASING TOWARD MIDWEEK AS A FRONTAL SYSTEM APPROACHES FROM THE NORTHWEST AND MOVES THROUGH THE AREA. DRY WEATHER AND COOL TEMPERATURES RETURN ONCE AGAIN FOR THE COMING WEEKEND AS ANOTHER DOME OF HIGH PRESSURE SETTLES OVER THE AREA. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1055 AM EDT MON AUG 5 2013 RADAR MOSAIC SHOWS SHOWERS AND THUNDERSTORMS ACROSS NORTHWEST ILLINOIS THAT ARE HEADED SOUTHEAST. CURRENTLY SATELLITE SHOWS MOSTLY CLEAR SKIES ACROSS MUCH OF THE AREA WITH CLOUDS ACROSS NORTHERN ILLINOIS HEADING SOUTHEAST TOWARD CENTRAL INDIANA. RAP AND HRRR SHOW THE AFOREMENTIONED STORMS EITHER STAYING JUST NORTH OF THE FORECAST AREA OR CLIPPING A FEW OF THE NORTHERN COUNTIES. LOOKING AT THE CURRENT MOVEMENT AND LOCATION OF HIGH SURFACE PRESSURE THINK THERE/S AN OUTSIDE CHANCE STORMS COULD SNEAK INTO THE FAR NORTHERN PARTS OF THE AREA LATE THIS AFTERNOON...SO ADDED A SLIGHT CHANCE FOR THUNDERSTORMS THERE FROM 4 PM ON. GOING HOURLY TEMPERATURES ARE ON TRACK FOR FORECAST HIGHS IN THE LOW 80S SO LEFT THEM ALONE. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 403 AM EDT MON AUG 5 2013 WILL CONTINUE TO CARRY POPS TONIGHT...BUT SLIGHT CHANCE TO LOW CHANCE AT BEST AS SUPPORT IS WEAK. MODELS HAVE EVEN BACKED OFF OF POTENTIAL FOR TUESDAY...BUT WITH BUFKIT SHOWING SOME MODEST CONVECTIVE INSTABILITY WILL CARRY A 30 POP FOR THUNDERSTORMS. HIGHER POPS REMAIN MERITED...BUT CANNOT GO LIKELY ANY PERIOD OWING TO CONTINUED DIFFERENCES BETWEEN MODELS AND RUN TO RUN INCONSISTENCIES WITH THE RELATIVELY WEAK DISTURBANCES MOVING THROUGH THE AREA. HIGHEST POPS WILL OF COURSE BE WITH THE POTENTIAL FRONT MOVING INTO THE AREA MIDWEEK. ON TEMPS...NEAR TO JUST ABOVE CONSENSUS NUMBERS APPEARS TO FIT BEST WITH 850 TEMP TRENDS ACROSS THE BOARD. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 249 AM EDT MON AUG 5 2013 ECMWF AND GFS CONTINUE TO INDICATE A COOL NORTHWEST FLOW ALOFT WITH FEW TO NO SHORT WAVE DISTURBANCES PASSING THROUGH THE FLOW INTO THE OHIO VALLEY. AT THE SURFACE A WEAK COLD FRONT IS EXPECTED TO BE PUSHING THROUGH AND EXITING THE AREA ON THURSDAY AND FRIDAY. BY FRIDAY AFTERNOON STRONG SURFACE HIGH PRESSURE LOOKS TO BE IN PLACE PROVING ANOTHER DRY WEEKEND WITH ANOTHER ROUND OF BELOW NORMAL TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 051500Z TAF UPDATE/... ISSUED AT 1033 AM EDT MON AUG 5 2013 FORECASTS IN GREAT SHAPE THIS MORNING. ONLY CHANGE WAS TO SLOW DOWN ARRIVAL OF THICKER MID LEVEL CLOUDS INTO THE EARLY AFTERNOON BASED ON CURRENT VIS SATELLITE. 12Z DISCUSSION FOLLOWS. AFTER SOME MORNING FOG...A QUICK RETURN TO VFR CONDITIONS IS EXPECTED FOR MUCH OF THIS TAF PERIOD. DIURNAL FOG AND LOW DEW POINT DEPRESSIONS WILL LINGER AT HUF...BMG AND LAF THIS MORNING. ONCE MIXING RESUMES A QUICK RETURN TO VFR IS EXPECTED AS FOG IS LOST. FORECAST SOUNDINGS TODAY SHOW REACHABLE CONVECTIVE TEMPS WITH CCL/S NEAR 4KFT. THUS HAVE TRENDED TOWARD SOME CU VFR CU THIS LATE THIS MORNING AND THIS AFTERNOON. A QUICK MOVING SHORT WAVE WILL APPROACH THE GREAT LAKES TONIGHT...BUT BEST MOISTURE AND FORCING WILL REMAIN NORTH OF THE TAF SITES. FORECAST SOUNDINGS AND TIME HEIGHT INDICATE SOME VFR CIGS ASSOCIATED WITH THIS FEATURE AS IT PASSES...AND THIS APPROACH SEEMS BEST. CLOUDS WITH THE PASSING SYSTEM SHOULD ALSO PREVENT ANY FOG OVERNIGHT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...NIELD NEAR TERM...CP SHORT TERM...NIELD LONG TERM....PUMA AVIATION...JP/RYAN VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1252 PM CDT MON AUG 5 2013 .SYNOPSIS... ISSUED AT 348 AM CDT MON AUG 5 2013 LATEST SFC ANALYSIS WAS INDICATING DEPARTING HIGH PRESSURE CENTERED OVER LOWER MI INTO NORTHWESTERN OH...WHILE RETURN FLOW CONTINUED TO ORGANIZE UP THE PLAINS AND JUST EAST OF THE MO RVR VALLEY. UPPER 60 TO AROUND 70 SFC DPTS WERE WRAPPING UP AROUND THE WESTERN FLANK OF THE RIDGE FROM THE LOWER MS RVR VALLEY...UP ACRS NEB. CURRENT MESOANALYSIS WAS INDICATING ELEVATED PLUME OF HIGHER THTA-E AIR GENERALLY ACRS THE SAME REGIONS...MAYBE GETTING PUSHED A BIT FURTHER EAST AND NORTHEAST OF THE THE SFC LAYER ACRS THE WESTERN THIRD OF IA. ALOFT...NORTHWEST FLOW CONTINUED WITH AN EMBEDDED WAVE PUSHING ACRS NORTHWESTERN INTO WEST CENTRAL MN DRIVING MAINLY AN ELEVATED MCS ACRS THE SOUTHEAST HALF OF MN. THIS ACTIVITY DROPPING SOUTHEAST ALONG THTA-E GRADIENT AND SHOULD MAKE IT INTO THE NORTHWESTERN AND NORTHERN PORTIONS OF THE DVN CWA THIS MORNING...POSSIBLY INDEPENDENCE BY 1030Z. OTHER STRONG THTA-E ADVECTION AND CONVERGENT FIELDS WERE FUELING HEAVY CONVECTIVE BANDS ACRS KS INTO SOUTHERN MO. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 348 AM CDT MON AUG 5 2013 TODAY...WILL WALK IN PORTION OF THE UPSTREAM MN/IA BORDER MCS INTO THE NORTHWESTERN TO NORTHERN THIRD OF THE DVN CWA THIS MORNING... BUT AS IT GETS AWAY FROM BETTER SUPPORT/H85 JET THTA-E FEED FEEL THE GENERAL WEAKENING TREND THAT THE LATEST RUN HRRR SUGGESTS WILL VERIFY AS IT SPILLS ALONG AND SOUTH OF HWY 30 AFTER 12Z THROUGH 14Z. BUT MAY STILL HAVE TO WATCH FOR A STRONG STORM IN THE FAR NORTHWESTERN CWA AS IT ARRIVES THOUGH AROUND 515 TO 530 AM CDT. WILL THEN WALK THE REST OF THE MCS AGAIN PROBABLY IN A DIURNALLY WEAKENING MODE ACRS THE NORTHERN THIRD OR A LITTLE MORE OF THE DVN CWA THROUGH LATE MORNING WITH HIGHEST POPS NORTH OF HWY 30. THEN AS CONVECTIVE DEBRIS CLEARS AND WARM AIR/THTA-E ADVECTION CONTINUE ACRS THE AREA INTO THE AFTERNOON...PORTIONS OF THE DVN CWA MAY BECOME RELATIVELY UNSTABLE ESPECIALLY THE SOUTHWESTERN HALF. REMNANT OUTFLOW BOUNDARIES AND A SECONDARY TYPE WARM FRONT MAY LAY OUT ACRS THE AREA AND ACT AS POTENTIAL FOCAL POINTS FOR AFTERNOON AND EARLY EVENING CONVECTION TO REFIRE ON. SOUTHERN PORTION OF THE NW MN WAVE AND RATHER VIGOROUS MID/UPPER JET STREAKS STREAMING ALONG AND JUST NORTH OF THE AREA COULD KICK OFF SCTRD STORMS THIS AFTERNOON WITH AN ISOLATED THREAT OF STRONG TO SVR STORMS LIKE SPC IS HINTING AT DUE TO INCREASING VERTICAL SHEAR PROFILES. BUT MUCH WILL DEPEND ON EVENTUAL HIGH TEMPS AROUND 80 OR WARMER AND IF SFC DPTS CAN MAKE IT AT LEAST INTO THE UPPER 60S. WILL GO WITH LOW TO MODERATE CHC POPS THIS AFTERNOON BECAUSE OF COVERAGE/INSTABILITY CONCERNS. HIGHS COOLER IN THE MID TO UPPER 70S IN THE NORTHEASTERN THIRD...TO THE LOW TO MID 80S IN THE SOUTHWEST WITH INCREASING BOUNDARY LAYER HUMIDITY. TONIGHT...WITH THE WAVE/VORT MAX SHEARING OFF TO THE EAST OF THE AREA...END OF LIFTING MECHANISMS AND DIURNAL PROCESSES SHOULD BRING ABOUT A DECREASE OF ANY PRECIP ACTIVITY AS THE EVENING PROGRESSES. NOCTURNAL LLJ PROGGED TO FOCUS BACK TO THE WEST AND SOUTH OF THE AREA AS WELL. WITH HIGHER DPTS IN PLACE AND LIGHT VARIABLE FLOW... ANY CLOUD CLEAR OUT MAY FOSTER FOG PRODUCTION ESPECIALLY IN AREAS THAT MANAGE TO GET SOME NEEDED RAINFALL. FOR NOW WILL JUST BLANKET THE CWA WITH PATCHY LATE NIGHT FOG WORDING. LOWS IN THE MID TO UPPER 60S IN MOST OF THE LOCAL FCST AREA. ..12.. .LONG TERM...(TUESDAY THROUGH NEXT SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 A SHORT WAVE AND COOL FRONT MOVING OUT OF THE NORTHERN PLAINS TUESDAY AND THROUGH THE MID AND UPPER MISSISSIPPI VALLEY BY WEDNESDAY MORNING WILL BRING A CHANCE OF THE THUNDERSTORMS TO THE REGION. TEMPERATURES AHEAD OF THE FRONT SHOULD RISE INTO THE 80S WITH DEWPOINTS IN THE UPPER 60S AND LOW 70S. SURFACE BASED CAPES BY MID AFTERNOON ARE EXPECTED TO BE AROUND 2K J/KG OVER MOST OF THE AREA. WITH THE INSTABILITY IN PLACE AND SOME WEAK UPPER FORCING SPREADING IN AHEAD OF THE MAIN SHORTWAVE...SOME ISOLATED TO SCATTERED STRONG STORMS WILL BE POSSIBLE DURING THE AFTERNOON AND HAVE INCLUDED SLIGHT CHANCE TO LOW CHANCE POPS FOR THE ENTIRE AREA AFTER 18Z. THE MAIN FORCING IS PROGGED TO MOVE THROUGH LATE TUESDAY NIGHT AND HAVE KEPT HIGH CHANCE TO LIKELY POPS DURING THIS PERIOD. THERE SHOULD BE ENOUGH INSTABILITY WITH MODERATE DEEP LAYER SHEAR FOR A RISK OF SEVERE STORMS OVERNIGHT. THE FRONT AND UPPER WAVE WILL BE EAST OF THE AREA BY WEDNESDAY MORNING BUT THE LOW LEVEL MOISTURE WILL BE SLOW TO LEAVE IN THE WEAK FLOW BEHIND THE FRONT SO HELD ON TO SOME LOW POPS EAST AND SOUTH WEDNESDAY. FOR THE REST OF THE FORECAST PERIOD NORTHWEST FLOW WILL REMAIN IN PLACE KEEPING MAINLY DRY AND COOLER THAN NORMAL CONDITIONS OVER THE AREA. THE MODELS ARE SHOWING A COUPLE OF WAVES MOVING OUT OF THE SOUTHERN ROCKIES AND THROUGH THE MID AND LOW MISSISSIPPI VALLEY WEDNESDAY THROUGH FRIDAY. THE NORTHERN EDGE OF THE PRECIPITATION BRUSHES THE FAR SOUTHERN COUNTIES SO KEPT SOME SLIGHT CHANCE POPS GOING IN THE SOUTH MID TO LATE WEEK. BROAD BRUSH SLIGHT CHANCE POPS WERE PLACED OVER THE FORECAST AREA FOR SUNDAY WITH THE ECMWF SHOWING A SHORT WAVE MOVING OUT OF THE NORTHERN PLAINS INTO THE UPPER MS VALLEY SUNDAY AND SUNDAY NIGHT. DLF && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1238 PM CDT MON AUG 5 2013 MORNING SHOWERS/STORMS ARE CURRENTLY EXITING TO THE EAST WITH LOW LEVEL CLOUDINESS CIGS 1-3K AGL IN ITS WAKE...WHICH HAVE BEEN GRADUALLY LIFTING. IMPULSE WILL MOVE ACROSS THE AREA THIS AFTERNOON/EARLY EVENING WITH A LOW PROBABILITY FOR SOME SHOWER/STORM ACTIVITY. LEFT OUT OF TAFS FOR NOW AND WILL AMEND AS SEE FIT. BEST AREAS FOR POSSIBLE CONVECTION IS NEAR THE BRL AND POSSIBLY CID AND MLI SITES. CLEARING AND LIGHT WINDS WILL BE COMMON BY MID EVENING...ALLOWING FOR FOG AND LOW CLOUDS OVERNIGHT AND TUESDAY AM. FOR NOW BROUGHT VSBYS DOWN TO 1 SM AND CIGS TO 1K FT AGL AFTER 08Z...BUT FEEL THIS MAY NOT BE LOW ENOUGH. WINDS WILL REMAIN SOUTHERLY AT 7-12 KTS...DIMINISHING TO NEARLY CALM BY MID TO LATE EVENING. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...12 SHORT TERM...12 LONG TERM...DLF AVIATION...14
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
646 AM CDT MON AUG 5 2013 .SYNOPSIS... ISSUED AT 348 AM CDT MON AUG 5 2013 LATEST SFC ANALYSIS WAS INDICATING DEPARTING HIGH PRESSURE CENTERED OVER LOWER MI INTO NORTHWESTERN OH...WHILE RETURN FLOW CONTINUED TO ORGANIZE UP THE PLAINS AND JUST EAST OF THE MO RVR VALLEY. UPPER 60 TO AROUND 70 SFC DPTS WERE WRAPPING UP AROUND THE WESTERN FLANK OF THE RIDGE FROM THE LOWER MS RVR VALLEY...UP ACRS NEB. CURRENT MESOANALYSIS WAS INDICATING ELEVATED PLUME OF HIGHER THTA-E AIR GENERALLY ACRS THE SAME REGIONS...MAYBE GETTING PUSHED A BIT FURTHER EAST AND NORTHEAST OF THE THE SFC LAYER ACRS THE WESTERN THIRD OF IA. ALOFT...NORTHWEST FLOW CONTINUED WITH AN EMBEDDED WAVE PUSHING ACRS NORTHWESTERN INTO WEST CENTRAL MN DRIVING MAINLY AN ELEVATED MCS ACRS THE SOUTHEAST HALF OF MN. THIS ACTIVITY DROPPING SOUTHEAST ALONG THTA-E GRADIENT AND SHOULD MAKE IT INTO THE NORTHWESTERN AND NORTHERN PORTIONS OF THE DVN CWA THIS MORNING...POSSIBLY INDEPENDENCE BY 1030Z. OTHER STRONG THTA-E ADVECTION AND CONVERGENT FIELDS WERE FUELING HEAVY CONVECTIVE BANDS ACRS KS INTO SOUTHERN MO. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 348 AM CDT MON AUG 5 2013 TODAY...WILL WALK IN PORTION OF THE UPSTREAM MN/IA BORDER MCS INTO THE NORTHWESTERN TO NORTHERN THIRD OF THE DVN CWA THIS MORNING... BUT AS IT GETS AWAY FROM BETTER SUPPORT/H85 JET THTA-E FEED FEEL THE GENERAL WEAKENING TREND THAT THE LATEST RUN HRRR SUGGESTS WILL VERIFY AS IT SPILLS ALONG AND SOUTH OF HWY 30 AFTER 12Z THROUGH 14Z. BUT MAY STILL HAVE TO WATCH FOR A STRONG STORM IN THE FAR NORTHWESTERN CWA AS IT ARRIVES THOUGH AROUND 515 TO 530 AM CDT. WILL THEN WALK THE REST OF THE MCS AGAIN PROBABLY IN A DIURNALLY WEAKENING MODE ACRS THE NORTHERN THIRD OR A LITTLE MORE OF THE DVN CWA THROUGH LATE MORNING WITH HIGHEST POPS NORTH OF HWY 30. THEN AS CONVECTIVE DEBRIS CLEARS AND WARM AIR/THTA-E ADVECTION CONTINUE ACRS THE AREA INTO THE AFTERNOON...PORTIONS OF THE DVN CWA MAY BECOME RELATIVELY UNSTABLE ESPECIALLY THE SOUTHWESTERN HALF. REMNANT OUTFLOW BOUNDARIES AND A SECONDARY TYPE WARM FRONT MAY LAY OUT ACRS THE AREA AND ACT AS POTENTIAL FOCAL POINTS FOR AFTERNOON AND EARLY EVENING CONVECTION TO REFIRE ON. SOUTHERN PORTION OF THE NW MN WAVE AND RATHER VIGOROUS MID/UPPER JET STREAKS STREAMING ALONG AND JUST NORTH OF THE AREA COULD KICK OFF SCTRD STORMS THIS AFTERNOON WITH AN ISOLATED THREAT OF STRONG TO SVR STORMS LIKE SPC IS HINTING AT DUE TO INCREASING VERTICAL SHEAR PROFILES. BUT MUCH WILL DEPEND ON EVENTUAL HIGH TEMPS AROUND 80 OR WARMER AND IF SFC DPTS CAN MAKE IT AT LEAST INTO THE UPPER 60S. WILL GO WITH LOW TO MODERATE CHC POPS THIS AFTERNOON BECAUSE OF COVERAGE/INSTABILITY CONCERNS. HIGHS COOLER IN THE MID TO UPPER 70S IN THE NORTHEASTERN THIRD...TO THE LOW TO MID 80S IN THE SOUTHWEST WITH INCREASING BOUNDARY LAYER HUMIDITY. TONIGHT...WITH THE WAVE/VORT MAX SHEARING OFF TO THE EAST OF THE AREA...END OF LIFTING MECHANISMS AND DIURNAL PROCESSES SHOULD BRING ABOUT A DECREASE OF ANY PRECIP ACTIVITY AS THE EVENING PROGRESSES. NOCTURNAL LLJ PROGGED TO FOCUS BACK TO THE WEST AND SOUTH OF THE AREA AS WELL. WITH HIGHER DPTS IN PLACE AND LIGHT VARIABLE FLOW... ANY CLOUD CLEAR OUT MAY FOSTER FOG PRODUCTION ESPECIALLY IN AREAS THAT MANAGE TO GET SOME NEEDED RAINFALL. FOR NOW WILL JUST BLANKET THE CWA WITH PATCHY LATE NIGHT FOG WORDING. LOWS IN THE MID TO UPPER 60S IN MOST OF THE LOCAL FCST AREA. ..12.. .LONG TERM...(TUESDAY THROUGH NEXT SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 A SHORT WAVE AND COOL FRONT MOVING OUT OF THE NORTHERN PLAINS TUESDAY AND THROUGH THE MID AND UPPER MISSISSIPPI VALLEY BY WEDNESDAY MORNING WILL BRING A CHANCE OF THE THUNDERSTORMS TO THE REGION. TEMPERATURES AHEAD OF THE FRONT SHOULD RISE INTO THE 80S WITH DEWPOINTS IN THE UPPER 60S AND LOW 70S. SURFACE BASED CAPES BY MID AFTERNOON ARE EXPECTED TO BE AROUND 2K J/KG OVER MOST OF THE AREA. WITH THE INSTABILITY IN PLACE AND SOME WEAK UPPER FORCING SPREADING IN AHEAD OF THE MAIN SHORTWAVE...SOME ISOLATED TO SCATTERED STRONG STORMS WILL BE POSSIBLE DURING THE AFTERNOON AND HAVE INCLUDED SLIGHT CHANCE TO LOW CHANCE POPS FOR THE ENTIRE AREA AFTER 18Z. THE MAIN FORCING IS PROGGED TO MOVE THROUGH LATE TUESDAY NIGHT AND HAVE KEPT HIGH CHANCE TO LIKELY POPS DURING THIS PERIOD. THERE SHOULD BE ENOUGH INSTABILITY WITH MODERATE DEEP LAYER SHEAR FOR A RISK OF SEVERE STORMS OVERNIGHT. THE FRONT AND UPPER WAVE WILL BE EAST OF THE AREA BY WEDNESDAY MORNING BUT THE LOW LEVEL MOISTURE WILL BE SLOW TO LEAVE IN THE WEAK FLOW BEHIND THE FRONT SO HELD ON TO SOME LOW POPS EAST AND SOUTH WEDNESDAY. FOR THE REST OF THE FORECAST PERIOD NORTHWEST FLOW WILL REMAIN IN PLACE KEEPING MAINLY DRY AND COOLER THAN NORMAL CONDITIONS OVER THE AREA. THE MODELS ARE SHOWING A COUPLE OF WAVES MOVING OUT OF THE SOUTHERN ROCKIES AND THROUGH THE MID AND LOW MISSISSIPPI VALLEY WEDNESDAY THROUGH FRIDAY. THE NORTHERN EDGE OF THE PRECIPITATION BRUSHES THE FAR SOUTHERN COUNTIES SO KEPT SOME SLIGHT CHANCE POPS GOING IN THE SOUTH MID TO LATE WEEK. BROAD BRUSH SLIGHT CHANCE POPS WERE PLACED OVER THE FORECAST AREA FOR SUNDAY WITH THE ECMWF SHOWING A SHORT WAVE MOVING OUT OF THE NORTHERN PLAINS INTO THE UPPER MS VALLEY SUNDAY AND SUNDAY NIGHT. DLF && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 632 AM CDT MON AUG 5 2013 CURRENT STORM CLUSTER AFFECTING CID...DBQ AND POSSIBLY MLI THROUGH 15Z THIS MORNING. SOUTHWEST FLOW 3-5K FT AGL ALOFT AT 20 KTS PRODUCING SOME MODERATE TURBULENCE IN THE LOWER LEVELS AROUND THE SHOWERS/STORMS. AFTER THE PRECIP CLEARS THIS MORNING...A PERIOD OF LOW VFR TO MVFR STRATOCU AT BKN TO OVC COVERAGE UNTIL THE AFTERNOON WHEN CIGS ARE EXPECTED TO LIFT TO VFR AND MORE SCTRD BREAKS. ISOLATED TO WDLY SCTRD SHOWERS AND THUNDERSTORMS MAY POP UP AGAIN IN THE AFTERNOON IN THE VCNTY OF ALL TERMINALS BUT MORE LIKELY ALONG AND NORTH OF I80. SOUTH TO SOUTHWEST SFC WINDS OF 7-12 KTS. HIGHER LEVELS OF SFC MOISTURE MAY COMBINE WITH CLEARING SKIES TONIGHT AND LIGHT WINDS TO PRODUCE AREAS OF FOG AFTER 05Z TUE. COVERAGE AND DENSITY STILL UNCERTAIN AT THIS TIME BUT WILL INCLUDE AT LEAST MVFR LEVEL FOG IN THE TAFS FOR NOW. ..12.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...12 SHORT TERM...12 LONG TERM...DLF AVIATION...12
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
349 AM CDT MON AUG 5 2013 .SYNOPSIS... ISSUED AT 348 AM CDT MON AUG 5 2013 LATEST SFC ANALYSIS WAS INDICATING DEPARTING HIGH PRESSURE CENTERED OVER LOWER MI INTO NORTHWESTERN OH...WHILE RETURN FLOW CONTINUED TO ORGANIZE UP THE PLAINS AND JUST EAST OF THE MO RVR VALLEY. UPPER 60 TO AROUND 70 SFC DPTS WERE WRAPPING UP AROUND THE WESTERN FLANK OF THE RIDGE FROM THE LOWER MS RVR VALLEY...UP ACRS NEB. CURRENT MESOANALYSIS WAS INDICATING ELEVATED PLUME OF HIGHER THTA-E AIR GENERALLY ACRS THE SAME REGIONS...MAYBE GETTING PUSHED A BIT FURTHER EAST AND NORTHEAST OF THE THE SFC LAYER ACRS THE WESTERN THIRD OF IA. ALOFT...NORTHWEST FLOW CONTINUED WITH AN EMBEDDED WAVE PUSHING ACRS NORTHWESTERN INTO WEST CENTRAL MN DRIVING MAINLY AN ELEVATED MCS ACRS THE SOUTHEAST HALF OF MN. THIS ACTIVITY DROPPING SOUTHEAST ALONG THTA-E GRADIENT AND SHOULD MAKE IT INTO THE NORTHWESTERN AND NORTHERN PORTIONS OF THE DVN CWA THIS MORNING...POSSIBLY INDEPENDENCE BY 1030Z. OTHER STRONG THTA-E ADVECTION AND CONVERGENT FIELDS WERE FUELING HEAVY CONVECTIVE BANDS ACRS KS INTO SOUTHERN MO. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 348 AM CDT MON AUG 5 2013 TODAY...WILL WALK IN PORTION OF THE UPSTREAM MN/IA BORDER MCS INTO THE NORTHWESTERN TO NORTHERN THIRD OF THE DVN CWA THIS MORNING... BUT AS IT GETS AWAY FROM BETTER SUPPORT/H85 JET THTA-E FEED FEEL THE GENERAL WEAKENING TREND THAT THE LATEST RUN HRRR SUGGESTS WILL VERIFY AS IT SPILLS ALONG AND SOUTH OF HWY 30 AFTER 12Z THROUGH 14Z. BUT MAY STILL HAVE TO WATCH FOR A STRONG STORM IN THE FAR NORTHWESTERN CWA AS IT ARRIVES THOUGH AROUND 515 TO 530 AM CDT. WILL THEN WALK THE REST OF THE MCS AGAIN PROBABLY IN A DIURNALLY WEAKENING MODE ACRS THE NORTHERN THIRD OR A LITTLE MORE OF THE DVN CWA THROUGH LATE MORNING WITH HIGHEST POPS NORTH OF HWY 30. THEN AS CONVECTIVE DEBRIS CLEARS AND WARM AIR/THTA-E ADVECTION CONTINUE ACRS THE AREA INTO THE AFTERNOON...PORTIONS OF THE DVN CWA MAY BECOME RELATIVELY UNSTABLE ESPECIALLY THE SOUTHWESTERN HALF. REMNANT OUTFLOW BOUNDARIES AND A SECONDARY TYPE WARM FRONT MAY LAY OUT ACRS THE AREA AND ACT AS POTENTIAL FOCAL POINTS FOR AFTERNOON AND EARLY EVENING CONVECTION TO REFIRE ON. SOUTHERN PORTION OF THE NW MN WAVE AND RATHER VIGOROUS MID/UPPER JET STREAKS STREAMING ALONG AND JUST NORTH OF THE AREA COULD KICK OFF SCTRD STORMS THIS AFTERNOON WITH AN ISOLATED THREAT OF STRONG TO SVR STORMS LIKE SPC IS HINTING AT DUE TO INCREASING VERTICAL SHEAR PROFILES. BUT MUCH WILL DEPEND ON EVENTUAL HIGH TEMPS AROUND 80 OR WARMER AND IF SFC DPTS CAN MAKE IT AT LEAST INTO THE UPPER 60S. WILL GO WITH LOW TO MODERATE CHC POPS THIS AFTERNOON BECAUSE OF COVERAGE/INSTABILITY CONCERNS. HIGHS COOLER IN THE MID TO UPPER 70S IN THE NORTHEASTERN THIRD...TO THE LOW TO MID 80S IN THE SOUTHWEST WITH INCREASING BOUNDARY LAYER HUMIDITY. TONIGHT...WITH THE WAVE/VORT MAX SHEARING OFF TO THE EAST OF THE AREA...END OF LIFTING MECHANISMS AND DIURNAL PROCESSES SHOULD BRING ABOUT A DECREASE OF ANY PRECIP ACTIVITY AS THE EVENING PROGRESSES. NOCTURNAL LLJ PROGGED TO FOCUS BACK TO THE WEST AND SOUTH OF THE AREA AS WELL. WITH HIGHER DPTS IN PLACE AND LIGHT VARIABLE FLOW... ANY CLOUD CLEAR OUT MAY FOSTER FOG PRODUCTION ESPECIALLY IN AREAS THAT MANAGE TO GET SOME NEEDED RAINFALL. FOR NOW WILL JUST BLANKET THE CWA WITH PATCHY LATE NIGHT FOG WORDING. LOWS IN THE MID TO UPPER 60S IN MOST OF THE LOCAL FCST AREA. ..12.. .LONG TERM...(TUESDAY THROUGH NEXT SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 A SHORT WAVE AND COOL FRONT MOVING OUT OF THE NORTHERN PLAINS TUESDAY AND THROUGH THE MID AND UPPER MISSISSIPPI VALLEY BY WEDNESDAY MORNING WILL BRING A CHANCE OF THE THUNDERSTORMS TO THE REGION. TEMPERATURES AHEAD OF THE FRONT SHOULD RISE INTO THE 80S WITH DEWPOINTS IN THE UPPER 60S AND LOW 70S. SURFACE BASED CAPES BY MID AFTERNOON ARE EXPECTED TO BE AROUND 2K J/KG OVER MOST OF THE AREA. WITH THE INSTABILITY IN PLACE AND SOME WEAK UPPER FORCING SPREADING IN AHEAD OF THE MAIN SHORTWAVE...SOME ISOLATED TO SCATTERED STRONG STORMS WILL BE POSSIBLE DURING THE AFTERNOON AND HAVE INCLUDED SLIGHT CHANCE TO LOW CHANCE POPS FOR THE ENTIRE AREA AFTER 18Z. THE MAIN FORCING IS PROGGED TO MOVE THROUGH LATE TUESDAY NIGHT AND HAVE KEPT HIGH CHANCE TO LIKELY POPS DURING THIS PERIOD. THERE SHOULD BE ENOUGH INSTABILITY WITH MODERATE DEEP LAYER SHEAR FOR A RISK OF SEVERE STORMS OVERNIGHT. THE FRONT AND UPPER WAVE WILL BE EAST OF THE AREA BY WEDNESDAY MORNING BUT THE LOW LEVEL MOISTURE WILL BE SLOW TO LEAVE IN THE WEAK FLOW BEHIND THE FRONT SO HELD ON TO SOME LOW POPS EAST AND SOUTH WEDNESDAY. FOR THE REST OF THE FORECAST PERIOD NORTHWEST FLOW WILL REMAIN IN PLACE KEEPING MAINLY DRY AND COOLER THAN NORMAL CONDITIONS OVER THE AREA. THE MODELS ARE SHOWING A COUPLE OF WAVES MOVING OUT OF THE SOUTHERN ROCKIES AND THROUGH THE MID AND LOW MISSISSIPPI VALLEY WEDNESDAY THROUGH FRIDAY. THE NORTHERN EDGE OF THE PRECIPITATION BRUSHES THE FAR SOUTHERN COUNTIES SO KEPT SOME SLIGHT CHANCE POPS GOING IN THE SOUTH MID TO LATE WEEK. BROAD BRUSH SLIGHT CHANCE POPS WERE PLACED OVER THE FORECAST AREA FOR SUNDAY WITH THE ECMWF SHOWING A SHORT WAVE MOVING OUT OF THE NORTHERN PLAINS INTO THE UPPER MS VALLEY SUNDAY AND SUNDAY NIGHT. DLF && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1150 PM CDT SUN AUG 4 2013 THUNDERSTORMS IN SOUTHERN MINNESOTA ARE EXPECTED TO TRACK SOUTHEASTWARD INTO NORTHEAST IOWA BY 12Z...POTENTIALLY AFFECTING AREA TAF SITES NORTH OF I80 INCLUDING DBQ...CID...AND POSSIBLY MLI. OTHERWISE...VFR CIGS WILL CONTINUE BEFORE THE STORMS...WITH MVFR CIGS LINGERING AFTERWARD THROUGH MUCH OF MONDAY. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...12 SHORT TERM...12 LONG TERM...DLF AVIATION...DMD
AREA FORECAST DISCUSSION
NWS GOODLAND KS
748 PM MDT TUE AUG 6 2013 .UPDATE... ISSUED AT 745 PM MDT TUE AUG 6 2013 UPDATED TO REMOVE THE CONVECTIVE WATCH AND ACCOUNT FOR DECREASING THUNDERSTORM COVERAGE ACROSS THE SOUTH AND ADDITIONAL THUNDERSTORMS MOVING ACROSS NORTHEAST COLORADO INTO FAR SOUTHWEST NEBRASKA AND FAR NORTHWEST KANSAS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 222 PM MDT TUE AUG 6 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS FEATURE. THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT. WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 246 PM MDT TUE AUG 6 2013 FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL WEATHER PATTERN WILL REMAIN LARGELY UNCHANGED. AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE AREA WEDNESDAY NIGHT AND SLOWLY GLIDE EASTWARD ACROSS THE AREA WITH ANOTHER ONE FOLLOWING IT OVER THE AREA THURSDAY. WITH THE MID THROUGH UPPER LEVELS NEARLY TO TOTALLY SATURATED AND THE RIGHT ENTRANCE OF THE 300MB JET OVER THE AREA AS THESE TROUGHS MOVE THROUGH...AM THINKING THERE SHOULD BE A GOOD CHANCE FOR SCATTERED TO WIDESPREAD RAINFALL DEVELOPMENT. THE BEST AREA FOR PRECIP. CHANCES LOOKS TO BE OVER THE SOUTH HALF WHERE THE BETTER FORCING AND LIFT WILL BE. PRECIP. CHANCES TAPER OFF THURSDAY NIGHT FROM WEST TO EAST AS THE UPPER LEVEL TROUGH MOVES OUT OF THE AREA AND DRIER AIR MOVES IN BEHIND IT. WEDNESDAY EVENING LOOKS TO BE THE BEST CHANCE FOR SEVERE STORM DEVELOPMENT DUE TO 0-6KM SHEAR OF 30-50KTS. HOWEVER ANY SEVERE STORMS THAT DEVELOP SHOULD REMAIN CONFINED TO THE WESTERN AND SOUTHERN FRINGES OF THE AREA WHERE THE BEST INSTABILITY WILL BE LOCATED. HEAVY RAINFALL WILL BE THE PREDOMINANT THREAT DURING THIS TIMEFRAME DUE TO STORM MOTIONS OF 5-10KTS. A FLASH FLOOD WATCH WILL LIKELY BE NEEDED FROM WEDNESDAY THROUGH THURSDAY MORNING FOR THE SOUTHERN TWO ROWS OF COUNTIES WHERE STORM COVERAGE WILL BE MOST WIDESPREAD. AFTER SOME DISCUSSION WILL HOLD OFF ISSUING THE WATCH FOR NOW TO PREVENT CONFUSION WITH ANY POTENTIAL FLOODING THREAT FROM TODAY/S STORM ACTIVITY. FOR FRIDAY THROUGH TUESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST CONUS WILL BUILD A BIT FURTHER NORTH...WITH THE NORTHERN PERIPHERY OF THE RIDGE OVER THE AREA. MULTIPLE UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE ACROSS THE AREA DURING THIS TIME CAUSING THERE TO BE PRECIP. CHANCES FOR NEARLY EVERY DAY. MEANWHILE THE WEAK FRONT THAT HAS BEEN WEST OF THE AREA WILL MOVE EAST ACROSS THE AREA DURING THE WEEKEND INTO EARLY NEXT WEEK. AS A RESULT TEMPERATURES WILL RETURN TO NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 552 PM MDT TUE AUG 6 2013 ISOLATED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE ACROSS THE CENTRAL HIGH PLAINS...BUT THE POSSIBILITY OF ANY OF THEM MOVING ACROSS EITHER MCK OR GLD TAF SITES ARE SLIM. HAVE LEFT ANY MENTION OF THUNDERSTORMS OUT OF THE TAFS THROUGH THE OVERNIGHT PERIOD. EXPECT GLD TO REMAIN VFR THROUGH THE PERIOD WITH SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z ON WEDNESDAY. MCK WILL REMAIN MOSTLY VFR WITH A POSSIBILITY OF FOG FORMING BETWEEN 10Z- 14Z. ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE AFTER ABOUT 22Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...LOCKHART SHORT TERM...DR LONG TERM...JTL AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS TOPEKA KS
746 PM CDT Tue Aug 6 2013 .Update... Issued at 641 PM CDT Tue Aug 6 2013 HRRR model seems to have predicted the location of the developing MCS across southwest Kansas, though the speed of propagation depicted by the HRRR model of this MCS looks to be about 2 to 3 hours too fast. the the northern edge of the MCS or leftover complex of thunderstorms may move east across the south central Kansas into the southern counties of the CWA after 100 AM. If the northern edge of this complex of thunderstorms actually moves across the southern counties of the CWA then there may be periods of heavy rainfall during the early morning hours generally south of an Abilene, to Ottawa, line given PW values of 1.8 inches. There may also be isolated to scattered thunderstorms developing along a cold front in south central NE that may move southeast into portions of north central and northeast Kansas after Midnight. Isolated showers and thunderstorm may develop along or just north of an outflow boundary along I-70 across central Kansas and move southeast across portions the southern counties of the CWA through the evening hours. .Short term...(This evening through Wednesday) Issued AT 319 PM CDT Tue Aug 6 2013 At 3 PM on Wednesday, a warm and moist airmass remained in place across all of Kansas. A warm front remained situated along the Kansas Oklahoma border while a weak outflow boundary remnant from early morning storms had stalled in northern Kansas. The other feature of note is a cold front moving into Nebraska from SD. Temperatures around 90 and dewpoints in the low to mid 70s were leading to MLCAPE values across much of the area up to 4000 J/KG. Upslope flow in western Kansas along with another weak short wave trough has initiated thunderstorms near the Colorado border... similar to Monday afternoon. This western KS activity is expected to build east and southeast into south central Kansas again today, but as the low level jet increases this evening expect the complex to build more northeast. The HRRR, which has performed rather well in the past few days, suggests that this convective complex will be enhanced by additional low level jet driven convection and will track from south central Kansas up the Kansas turnpike and across east central Kansas. A few of these individual storms may be strong with damaging winds possible mainly near and south of the turnpike. Heavy rain will also be likely, but the heaviest elements are expected to be progressive in nature and widespread heavy rain is not expected at this time, although isolated flooding will be possible. Additional storms may move out of Nebraska along the cold front after midnight, and could also be strong as they enter Kansas. There is the potential for multiple fronts/boundaries to be in place across the area on Wednesday, although the main cold front should also slowly sink into Kansas. These boundaries may serve as a focus for scattered storms throughout the day, but expect most areas to be dry during the daylight hours. Temperatures will be a bit cooler, but the very moist airmass will remain in place for much of the area. Barjenbruch .Long term...(Wednesday night through Tuesday) Issued AT 319 PM CDT Tue Aug 6 2013 Wednesday evening through Friday... Currently watching the next potent shortwave trough currently rotating over far southern Arizona at this hour. This wave will bring the highest chances for convective rainfall beginning Wednesday evening. Timing with this wave continues to slightly vary between each model run unfortunately leading to some uncertainty as to when heaviest rainfall will occur. Smaller embedded troughs ejected from the main shortwave could bring scattered showers and thunderstorms early on Wednesday evening before an mcs develops over western KS and traverses east through Kansas early Thursday. Highest chances for rainfall were emphasized mainly along and south of Interstate 70. Strong isentropic lift maximizes from 305 to 315k surfaces with a strong baroclinc zone in place suggesting widespread moderate to heavy rainfall. Precipitable water values agree with this scenario reaching over 2.25 inches...two standard deviations above normal. High rainfall rates may quickly lead to flash flooding and river flooding concerns for much of the cwa as current flash flood guidance only holds around 2 inches of rainfall in a three hour period. A flood watch will need to be considered in the upcoming shifts for this period. The main wave slowly lifts northeast Thursday evening with another possible mcs developing along and behind a cold front. GFS and ECMWF both indicate a complex developing over western Nebraska tracking southeast into northeast Kansas into Friday with precip slowly tapering off west to east as subsidence builds in the late afternoon. Temperatures were lowered a few degrees on Thursday afternoon as progged rainfall throughout the day with no cloud clearing expected should hold readings in the middle to upper 70s. Drier air entering from Nebraska Friday will clear out the stratus clouds with highs in the low 80s. Friday evening through Tuesday... Subsidence building behind the wave should bring a temporary lull in the rain Friday evening through Saturday afternoon. Run to run consistency between the GFS and ECWMF contains plenty of discrepancies but overall pattern characterizes the upper ridge over the western conus building once again with northwest flow increasing over the area Sunday. Periods of off and on showers and thunderstorms begin on Sunday afternoon and continue through Tuesday as a series of shortwave troughs translate along the edge of the ridge. High are generally in the mid to upper 80s...combined with dewpoints in the upper 60s should continue with the warm and muggy conditions. && .Aviation...(for the 00Z TAFS through 00Z Wednesday evening) issued at 626 PM CDT Tue Aug 6 2013 Expect mainly VFR conditions at the TAF sites. Scattered thunderstorms may develop late this evening and move east across the TAF sites through sunrise. I kept VCTS in TAFS from 5Z through 11Z. After CU will develop with bases of 6 to 8 thousand feet. Late Wednesday afternoon isolated to scattered thunderstorms may redevelop across the TAF sites. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ Updat...Gargan Short term...Barjenbruch Long term..Bowen Aviation...Gargan
AREA FORECAST DISCUSSION
NWS GOODLAND KS
556 PM MDT TUE AUG 6 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 222 PM MDT TUE AUG 6 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS FEATURE. THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT. WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 246 PM MDT TUE AUG 6 2013 FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL WEATHER PATTERN WILL REMAIN LARGELY UNCHANGED. AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE AREA WEDNESDAY NIGHT AND SLOWLY GLIDE EASTWARD ACROSS THE AREA WITH ANOTHER ONE FOLLOWING IT OVER THE AREA THURSDAY. WITH THE MID THROUGH UPPER LEVELS NEARLY TO TOTALLY SATURATED AND THE RIGHT ENTRANCE OF THE 300MB JET OVER THE AREA AS THESE TROUGHS MOVE THROUGH...AM THINKING THERE SHOULD BE A GOOD CHANCE FOR SCATTERED TO WIDESPREAD RAINFALL DEVELOPMENT. THE BEST AREA FOR PRECIP. CHANCES LOOKS TO BE OVER THE SOUTH HALF WHERE THE BETTER FORCING AND LIFT WILL BE. PRECIP. CHANCES TAPER OFF THURSDAY NIGHT FROM WEST TO EAST AS THE UPPER LEVEL TROUGH MOVES OUT OF THE AREA AND DRIER AIR MOVES IN BEHIND IT. WEDNESDAY EVENING LOOKS TO BE THE BEST CHANCE FOR SEVERE STORM DEVELOPMENT DUE TO 0-6KM SHEAR OF 30-50KTS. HOWEVER ANY SEVERE STORMS THAT DEVELOP SHOULD REMAIN CONFINED TO THE WESTERN AND SOUTHERN FRINGES OF THE AREA WHERE THE BEST INSTABILITY WILL BE LOCATED. HEAVY RAINFALL WILL BE THE PREDOMINANT THREAT DURING THIS TIMEFRAME DUE TO STORM MOTIONS OF 5-10KTS. A FLASH FLOOD WATCH WILL LIKELY BE NEEDED FROM WEDNESDAY THROUGH THURSDAY MORNING FOR THE SOUTHERN TWO ROWS OF COUNTIES WHERE STORM COVERAGE WILL BE MOST WIDESPREAD. AFTER SOME DISCUSSION WILL HOLD OFF ISSUING THE WATCH FOR NOW TO PREVENT CONFUSION WITH ANY POTENTIAL FLOODING THREAT FROM TODAY/S STORM ACTIVITY. FOR FRIDAY THROUGH TUESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST CONUS WILL BUILD A BIT FURTHER NORTH...WITH THE NORTHERN PERIPHERY OF THE RIDGE OVER THE AREA. MULTIPLE UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE ACROSS THE AREA DURING THIS TIME CAUSING THERE TO BE PRECIP. CHANCES FOR NEARLY EVERY DAY. MEANWHILE THE WEAK FRONT THAT HAS BEEN WEST OF THE AREA WILL MOVE EAST ACROSS THE AREA DURING THE WEEKEND INTO EARLY NEXT WEEK. AS A RESULT TEMPERATURES WILL RETURN TO NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 552 PM MDT TUE AUG 6 2013 ISOLATED SHOWERS AND A FEW THUNDERSTORMS ARE POSSIBLE ACROSS THE CENTRAL HIGH PLAINS...BUT THE POSSIBILITY OF ANY OF THEM MOVING ACROSS EITHER MCK OR GLD TAF SITES ARE SLIM. HAVE LEFT ANY MENTION OF THUNDERSTORMS OUT OF THE TAFS THROUGH THE OVERNIGHT PERIOD. EXPECT GLD TO REMAIN VFR THROUGH THE PERIOD WITH SCATTERED THUNDERSTORMS DEVELOPING AFTER 18Z ON WEDNESDAY. MCK WILL REMAIN MOSTLY VFR WITH A POSSIBILITY OF FOG FORMING BETWEEN 10Z- 14Z. ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE AFTER ABOUT 22Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JTL AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS TOPEKA KS
653 PM CDT Tue Aug 6 2013 .UPDATE... Issued at 641 PM CDT Tue Aug 6 2013 HRRR model seems to have predicted the location of the developing MCS across southwest Kansas, though the speed of propagation depicted by the HRRR model of this MCS looks to be about 2 to 3 hours too fast. the the northern edge of the MCS or leftover complex of thunderstorms may move east across the south central Kansas into the southern counties of the CWA after 100 AM. If the northern edge of this complex of thunderstorms actually moves across the southern counties of the CWA then there may be periods of heavy rainfall during the early morning hours generally south of an Abilene, to Ottawa, line given PW values of 1.8 inches. There may also be isolated to scattered thunderstorms developing along a cold front in south central NE that may move southeast into portions of north central and northeast Kansas after Midnight. Isolated showers and thunderstorm may develop along or just north of an outflow boundary along I-70 across central Kansas and move southeast across portions the southern counties of the CWA through the evening hours. .Short Term...(This evening through Wednesday) Issued AT 319 PM CDT Tue Aug 6 2013 At 3 PM on Wednesday, a warm and moist airmass remained in place across all of Kansas. A warm front remained situated along the Kansas Oklahoma border while a weak outflow boundary remnant from early morning storms had stalled in northern Kansas. The other feature of note is a cold front moving into Nebraska from SD. Temperatures around 90 and dewpoints in the low to mid 70s were leading to MLCAPE values across much of the area up to 4000 J/KG. Upslope flow in western Kansas along with another weak short wave trough has initiated thunderstorms near the Colorado border... similar to Monday afternoon. This western KS activity is expected to build east and southeast into south central Kansas again today, but as the low level jet increases this evening expect the complex to build more northeast. The HRRR, which has performed rather well in the past few days, suggests that this convective complex will be enhanced by additional low level jet driven convection and will track from south central Kansas up the Kansas turnpike and across east central Kansas. A few of these individual storms may be strong with damaging winds possible mainly near and south of the turnpike. Heavy rain will also be likely, but the heaviest elements are expected to be progressive in nature and widespread heavy rain is not expected at this time, although isolated flooding will be possible. Additional storms may move out of Nebraska along the cold front after midnight, and could also be strong as they enter Kansas. There is the potential for multiple fronts/boundaries to be in place across the area on Wednesday, although the main cold front should also slowly sink into Kansas. These boundaries may serve as a focus for scattered storms throughout the day, but expect most areas to be dry during the daylight hours. Temperatures will be a bit cooler, but the very moist airmass will remain in place for much of the area. Barjenbruch .Long Term...(Wednesday night through Tuesday) Issued AT 319 PM CDT Tue Aug 6 2013 Wednesday evening through Friday... Currently watching the next potent shortwave trough currently rotating over far southern Arizona at this hour. This wave will bring the highest chances for convective rainfall beginning Wednesday evening. Timing with this wave continues to slightly vary between each model run unfortunately leading to some uncertainty as to when heaviest rainfall will occur. Smaller embedded troughs ejected from the main shortwave could bring scattered showers and thunderstorms early on Wednesday evening before an mcs develops over western KS and traverses east through Kansas early Thursday. Highest chances for rainfall were emphasized mainly along and south of Interstate 70. Strong isentropic lift maximizes from 305 to 315k surfaces with a strong baroclinc zone in place suggesting widespread moderate to heavy rainfall. Precipitable water values agree with this scenario reaching over 2.25 inches...two standard deviations above normal. High rainfall rates may quickly lead to flash flooding and river flooding concerns for much of the cwa as current flash flood guidance only holds around 2 inches of rainfall in a three hour period. A flood watch will need to be considered in the upcoming shifts for this period. The main wave slowly lifts northeast Thursday evening with another possible mcs developing along and behind a cold front. GFS and ECMWF both indicate a complex developing over western Nebraska tracking southeast into northeast Kansas into Friday with precip slowly tapering off west to east as subsidence builds in the late afternoon. Temperatures were lowered a few degrees on Thursday afternoon as progged rainfall throughout the day with no cloud clearing expected should hold readings in the middle to upper 70s. Drier air entering from Nebraska Friday will clear out the stratus clouds with highs in the low 80s. Friday evening through Tuesday... Subsidence building behind the wave should bring a temporary lull in the rain Friday evening through Saturday afternoon. Run to run consistency between the GFS and ECWMF contains plenty of discrepancies but overall pattern characterizes the upper ridge over the western conus building once again with northwest flow increasing over the area Sunday. Periods of off and on showers and thunderstorms begin on Sunday afternoon and continue through Tuesday as a series of shortwave troughs translate along the edge of the ridge. High are generally in the mid to upper 80s...combined with dewpoints in the upper 60s should continue with the warm and muggy conditions. && .Aviation...(for the 00Z TAFS through 00Z Wednesday evening) issued at 626 PM CDT Tue Aug 6 2013 Expect mainly VFR conditions at the TAF sites. Scattered thunderstorms may develop late this evening and move east across the TAF sites through sunrise. I kept VCTS in TAFS from 5Z through 11Z. After CU will develop with bases of 6 to 8 thousand feet. Late Wednesday afternoon isolated to scattered thunderstorms may redevelop across the TAF sites. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ Updat...Gargan Short term...Barjenbruch Long term..Bowen Aviation...Gargan
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
617 AM CDT Mon Aug 5 2013 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 451 AM CDT MON AUG 5 2013 Light southeast surface winds were prevalent across the area this morning with anomalously high dew points around 70 degrees across most of central and sw Kansas. Dew point depression have decreased to a few degrees in the extreme southwest to zero in parts of central Kansas. Stratus had developed overnight across most of the region and dense fog development appeared to be accelerating across central Kansas as well from areas around Great Bend to Pratt. On the larger scale, the 850 mb analysis indicated a large area of 850 mb dew points in excess of 18 degrees c across the central high plains. The mesoanalysis also indicated precipitable water values exceeding 1.5 inches across a large portion of western Kansas. && .SHORT TERM...(Today and tonight) ISSUED AT 451 AM CDT MON AUG 5 2013 Today`s forecast will be a challenge on several fronts, including this morning`s low stratus and fog, followed by warm temperatures today, the onset of any afternoon convection as well as heavy rain and flooding potential later tonight. The fog advisory will remain intact as visibilities continue to deteriorate across central Kansas. Locations along and east of highway 283 appear to have the greatest chances for dense fog development through the early morning. the fog should dissipate as temperatures warm through the mid morning hours. Models warm temperatures into the upper 90s to around 100 degrees in the extreme southern counties. A warm frontal boundary should lift northward, aiding surface dew points to mix out to slightly lower values across the far southern areas. Higher relative HUMIDITIES will be likely across the hays to Pratt regions. There will be severe weather chances later this afternoon. Large hail and damaging wind will be possible late in the day into this evening and severe watches are probable for portions of western Kansas especially if a warm frontal zone/surface wind shift develops in the vicinity of the larger surface low feature across eastern Colorado and west central Kansas. Given the water loaded nature of any supercells, wet macroburst type wind events may be the greatest threat in addition to golf ball sized or larger hail. Localized flash flooding may also develop if storms train over the same areas later this evening. Although a flood watch was considered, given less certainty in storm motions and speeds and greatest threat location, we will not issue a flood watch at this time. .LONG TERM...(Tuesday through Sunday) ISSUED AT 339 AM CDT MON AUG 5 2013 Upper level high that was located over the panhandle of Texas earlier this morning will slowly drift southeast across central Kansas early next week. As this upper high moves south the upper level ridge axis located across the Rockies will weaken as an upper level trough drops out of central Canada and into the northern plains. Tuesday night and early Wednesday a cold front will drop south across the central plains as the northern plains upper level trough moves into the western great lakes. As this cold front move south across western Kansas Tuesday night the precipitation chances will once again improve. Not only with there be a chance for thunderstorms with the frontal passage Tuesday night, but also given the upslope flow and moisture forecast by the ECMWF and GFS behind this front there will also be high chance to likely chances for convection Wednesday night and/or Thursday as an upper level trough exits the Rockies and moves across the central high plains. Timing appears to be an issue on this next more significant upper level trough have decided to stay close to the previous forecast but trend precipitation chances up on Wednesday night and Thursday. Warm 925-850mb temperatures ahead of the cold front on Tuesday continues to support highs near 100 degrees for at least southwest and south central Kansas. Behind the front 850mb temperature trends from the ECMWF and GFS suggest at least a 6c to 8c drop between 00z Wednesday to 00z Thursday. This combined the potential for some clouds and possible precipitation continues to support highs mainly in the low to mid 80s on Wednesday. mid to upper 70s for highs not out of the question across north central and west central Kansas if the cloud cover and ECMWF and NAM 925-850mb temperatures at 18z Wednesday and 00z Thursday are correct. Temperatures will then begin to warm Friday into the weekend period as the surface boundary lifts back north as a warm front. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 614 AM CDT MON AUG 5 2013 LIFR conditions can be expected at all three taf sites early this morning given light southeast winds, and low level moisture present across western Kansas. Bufr soundings and HRRR both were in decent agreement with the vsby improving quicker than the status and VFR conditions will develop by 15z at DDC and GCK. VFR conditions are expected at HYS by 17z. Scattered late day thunderstorms will be possible near a warm front that is expected to be located between DDC and HYS late this afternoon. Convection will increase in areal coverage early tonight so introduce thunderstorms into all three tafs after 00z. && .PRELIMINARY POINT TEMPS/POPS... DDC 98 70 96 67 / 20 60 50 50 GCK 98 69 94 66 / 20 70 50 50 EHA 98 70 96 65 / 20 40 40 30 LBL 100 70 98 67 / 20 50 40 40 HYS 91 70 92 68 / 30 90 50 40 P28 99 73 99 72 / 10 60 50 40 && .DDC WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY until 9 AM CDT /8 AM MDT/ this morning FOR KSZ030-031-043>046-061>066-075>081-086>090. && $$ SYNOPSIS...RUSSELL SHORT TERM...RUSSELL LONG TERM...BURGERT AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1022 PM CDT Tue Aug 6 2013 .UPDATE... ISSUED AT 1019 PM CDT TUE AUG 6 2013 Updated Aviation section UPDATE ISSUED AT 830 PM CDT TUE AUG 6 2013 Latest convection allowing mesoscale models indicate the likelihood of another mcs developing or moving into Missouri around 06z...then moving east/southeast across portions of our forecast area toward morning. The 12z nmm and arw both show convection over Iowa moving southeast across the Lower Ohio River Valley and southeast Missouri around 12z. The latest HRRR model reflectivity indicates a repeat occurrence of last night...with a slow moving mcs forming over the Ozarks tonight and progressing east across the Lower Ohio Valley Wed morning. The latest RAP model indicates a 500 mb shortwave /possible mcv/ over Kansas will move east to the Ozarks by 12z. Ahead of this feature...the 850 mb low level jet is forecast to strengthen to around 30 knots over the Ozarks tonight. All in all...it looks like potentially another favorable setup for a flash flood event in Missouri late tonight. Given decent agreement among the mesoscale models...will adjust pops upward for se Missouri overnight and mention heavy rain there. This will be the main area for flood potential through early Wednesday. Will lower pops somewhat for sw Indiana and nearby portions of IL and KY overnight. Best potential for heavy rain in those areas appears to be mainly after 12z. && .SHORT TERM...(This Evening through Wednesday) ISSUED AT 248 PM CDT TUE AUG 6 2013 The latest model runs are not as consistent as one would like. However one thing is certain and that is its going to be a very wet week ahead. The latest surface analysis depicts a weak low near the MO boot heel with an associated warm meandering just south of the fa. This front will lift north and parallel the Mississippi River by sunset. As this front lifts northeast of the heartland surface based storms will develop in its wake. The combination of the open gulf in the low levels and the monsoonal flow aloft have resulted in PWATS at or approaching 2 inches and CAPE around 1000 j/kg tonight to around 3000 j/kg Wednesday. This combined with copious amounts of moisture will likely result in flooding in the stronger storms for sure. This will be compounded over urban areas. With this in mind now we can add a cold front to the mixture which will stall over the area by Thursday as winds will parallel to the front over the region. This will result in even more rainfall. Essentially the same efficient storms that have been west of the Mississippi this week will move east into our area. Rainfall rates exceeding an inch per hour will not only be possible but common. As for temperatures expect a warmup as the warm front overtakes the area tonight. .LONG TERM...(Wednesday Night through Tuesday) ISSUED AT 248 PM CDT TUE AUG 6 2013 Status quo goes the forecast for Friday right into the weekend. Stationary front to continue to meander somewhere along or just north of the Ohio River, weak monsoonal mid level short waves will continue to rotate east from the middle of the country in broad zonal flow, and PWATS should continue up around 2 inches laden with low lvl moisture from the Gulf of Mexico. Exactly when and where multiple rounds convective systems occur remains to be pin-pointed, but somewhere in the mid MS and/or lower Ohio Valley region is likely to receive more heavy rains...esp Friday into Saturday. Would not at all be surprised to see additional flash flood watches issued for this time frame as many locations may be quite soaked by then. In fact...there are some indications that moist/unsettled conditions may now last into Sunday and Monday. && .AVIATION... ISSUED AT 1019 PM CDT TUE AUG 6 2013 Cigs scattered out in the evening but some mvfr bases still linger. Ifr is not too far beyond the fa in scntl Mo, so we`ll introduce these lower clouds in the new set of 06z tafs as the late night convection starts to take shape and move in. Kcgi-Kpah should see showers with potential ifr restrictions late tonight and this will expand eastward/northward to affect Kevv-Kowb by morning daylight hours. Bulk of pcpn should end by planning period with comparable improvement thereafter. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH through Wednesday afternoon FOR ILZ075>078- 080>094. MO...FLASH FLOOD WATCH through Wednesday afternoon FOR MOZ076-086-087- 100-107>112-114. IN...FLASH FLOOD WATCH through Wednesday afternoon FOR INZ081-082- 085>088. KY...FLASH FLOOD WATCH through Wednesday afternoon FOR KYZ001>022. && $$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
830 PM CDT Tue Aug 6 2013 .UPDATE... ISSUED AT 830 PM CDT TUE AUG 6 2013 Latest convection allowing mesoscale models indicate the likelihood of another mcs developing or moving into Missouri around 06z...then moving east/southeast across portions of our forecast area toward morning. The 12z nmm and arw both show convection over Iowa moving southeast across the Lower Ohio River Valley and southeast Missouri around 12z. The latest HRRR model reflectivity indicates a repeat occurrence of last night...with a slow moving mcs forming over the Ozarks tonight and progressing east across the Lower Ohio Valley Wed morning. The latest RAP model indicates a 500 mb shortwave /possible mcv/ over Kansas will move east to the Ozarks by 12z. Ahead of this feature...the 850 mb low level jet is forecast to strengthen to around 30 knots over the Ozarks tonight. All in all...it looks like potentially another favorable setup for a flash flood event in Missouri late tonight. Given decent agreement among the mesoscale models...will adjust pops upward for se Missouri overnight and mention heavy rain there. This will be the main area for flood potential through early Wednesday. Will lower pops somewhat for sw Indiana and nearby portions of IL and KY overnight. Best potential for heavy rain in those areas appears to be mainly after 12z. && .SHORT TERM...(This Evening through Wednesday) ISSUED AT 248 PM CDT TUE AUG 6 2013 The latest model runs are not as consistent as one would like. However one thing is certain and that is its going to be a very wet week ahead. The latest surface analysis depicts a weak low near the MO boot heel with an associated warm meandering just south of the fa. This front will lift north and parallel the Mississippi River by sunset. As this front lifts northeast of the heartland surface based storms will develop in its wake. The combination of the open gulf in the low levels and the monsoonal flow aloft have resulted in PWATS at or approaching 2 inches and CAPE around 1000 j/kg tonight to around 3000 j/kg Wednesday. This combined with copious amounts of moisture will likely result in flooding in the stronger storms for sure. This will be compounded over urban areas. With this in mind now we can add a cold front to the mixture which will stall over the area by Thursday as winds will parallel to the front over the region. This will result in even more rainfall. Essentially the same efficient storms that have been west of the Mississippi this week will move east into our area. Rainfall rates exceeding an inch per hour will not only be possible but common. As for temperatures expect a warmup as the warm front overtakes the area tonight. .LONG TERM...(Wednesday Night through Tuesday) ISSUED AT 248 PM CDT TUE AUG 6 2013 Status quo goes the forecast for Friday right into the weekend. Stationary front to continue to meander somewhere along or just north of the Ohio River, weak monsoonal mid level short waves will continue to rotate east from the middle of the country in broad zonal flow, and PWATS should continue up around 2 inches laden with low lvl moisture from the Gulf of Mexico. Exactly when and where multiple rounds convective systems occur remains to be pin-pointed, but somewhere in the mid MS and/or lower Ohio Valley region is likely to receive more heavy rains...esp Friday into Saturday. Would not at all be surprised to see additional flash flood watches issued for this time frame as many locations may be quite soaked by then. In fact...there are some indications that moist/unsettled conditions may now last into Sunday and Monday. && .AVIATION... ISSUED AT 248 PM CDT TUE AUG 6 2013 MVFR cloud deck at KEVV and KOWB should mix out early this afternoon, leaving vfr conditions for the rest of the day and evening. There is some chc that sct thunderstorms may regenerate if we get decent heating, but confidence is too low to warrant mention of thunder in the TAFS as of 18z issuance. Thunder appears a bit more likely aft 06-08Z tonight if another convective complex can get going in srn/sern MO later this evening. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...FLASH FLOOD WATCH from Midnight CDT tonight through Wednesday afternoon FOR ILZ075>078-080>094. MO...FLASH FLOOD WATCH from Midnight CDT tonight through Wednesday afternoon FOR MOZ076-086-087-100-107>112-114. IN...FLASH FLOOD WATCH from Midnight CDT tonight through Wednesday afternoon FOR INZ081-082-085>088. KY...FLASH FLOOD WATCH from Midnight CDT tonight through Wednesday afternoon FOR KYZ001>022. && $$ UPDATE...MY SHORT TERM...KH LONG TERM...GM AVIATION...GM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
534 PM EDT MON AUG 5 2013 .SYNOPSIS... HIGH PRESSURE AT THE SURFACE WILL PROMOTE A DRY AND GENERALLY SUNNY DAY. A SLOW-MOVING UPPER-LEVEL DISTURBANCE WILL BE ACCOMPANIED BY INCREASING TEMPERATURES AND ACTIVE WEATHER TUESDAY THROUGH THURSDAY. && .NEAR TERM /THROUGH TUESDAY/... WITH 530PM UPDATE...HAVE BACKED OFF POPS A LITTLE BIT MORE DURING THE OVERNIGHT HOURS. THE LATEST RUNS OF BOTH THE RAP AND THE HRRR MODELS DO NOT SHOW ANY PRECIPITATION DURING THAT TIME PERIOD...BUT HAVE STILL LEFT SOME SLIGHT CHANCE POPS FOR CONSISTENCY. PREVIOUS DISCUSSION FOLLOWS. GUIDANCE HAS TRENDED CONSISTENTLY DRIER OVNGT TNGT. BUT INCRD WEAK FORCING AND MODEST MOISTURE ADVCTN COULD HELP ERADICATE SOME OF THE DRY AIR. THUS...POPS GENLY WERE LMTD TO SLGT CHC THRU MUCH OF TNGT. POPS WERE INCRD TO CHC VERY LATE TNGT IN A PORTION OF THE FCST AREA...WHERE BEST OPPORTUNITY FOR MOISTENING OF THE COLUMN WILL BE. MIXED SUN AND CLDS WILL CONT THRU TUE WITH LOW CHCS FOR PCPN OWING TO LMTD DP MSTR. ANY SHWRS ASSOCIATED WITH SHRTWV TROF PASSAGE WILL BE SCT IN CVRG AND WILL TRANSLATE INTO ERN ZONES BY LATE TUE AFTN. MAXIMA WILL BE NR NRML IN THE UPR 70S- LWR 80S. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A WK SHRTWV WL EXIT THE RGN TUE NGT WITH DCRG SHWR CHCS. ANOTHER SHRTWV WL MOVE ACRS THE RGN WED AHD OF AN APRCHG CDFNT. MAINTAINED LIKELY POPS ACRS THE AREA FOR SHWRS AND PSBL TSTMS. CAPES 1000-1500 J/KG EXPD WITH SOME INCR IN SHEAR AS WELL...ALTHOUGH SVR POTENTIAL APPEARS LOW ATTM. PWATS WL BE INCRG BUT APPEARS TO BE NO WDSPRD FLOODING CONCERNS ATTM AS WELL. THE CDFNT SHOULD DRIFT SEWD ACRS THE AREA LT WED NGT INTO THU WITH BEST CHC POPS S AND E OF PIT. TEMPS EXPD TO BE NR SEASONAL AVGS. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A WAVE IS EXPD TO MOVE E THRU THE OH VLY ALG A STALLED CDFNT THU NGT INTO FRI...KEEPING SHWR AND TSTM CHCS IN THE FCST. A SECONDARY CDFNT SHOULD PUSH S OF THE RGN FRI NGT...RETURNING DRY WEA AND BLO AVG TEMPS FOR THE WEEKEND INTO ERLY NXT WK. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... DRY LOW-LVL AMS AND INCRG CLD CVR WILL LMT RESTRICTIONS TNGT. IF ANY FOG DVLPS...IT LKLY WILL BARELY BROACH MVFR CATEGORY. THERE IS A SMALL PSBLTY OF LGT RAIN AT KFKL...BUT DRY COLUMN SHOULD LMT POTL. GENLY VFR CONDS XPCD TUE. SCT SHWRS MAY DVLP TUE AFTN AS WEAK SHRTWV TROF CROSSES THE RGN. BRIEF RESTRICTIONS WILL BE PSBL IN ANY SHWRS...BUT CHC OF IMPACTING ANY PARTICULAR TERMINAL IS LOW. OUTLOOK.../TUESDAY THROUGH SATURDAY/... OCNL RESTRICTIONS IN SHWRS AND TSTMS PSBL WED-THU. LOW-LVL MSTR WILL INCR SGFNTLY WED-THU...LEADING TO PSBL RESTRICTIONS IN OVNGT FOG. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1156 PM EDT TUE AUG 6 2013 .AVIATION... //DISCUSSION... WITH CONVECTION HOLDING TOGETHER AS IT TRACKS ACROSS NORTHERN WISCONSIN...IT IS LOOKING INCREASINGLY LIKELY THAT AT LEAST REMNANT SHRAS/TSRAS MAKE IT INTO THE CWA LATE TONIGHT/DAYBREAK AS A 20KT SW LOW LEVEL JET FEEDS MOISTURE INTO THE AREA. WILL INTRODUCE A TEMPO FOR SHRAS/TSRAS TO MBS/FNT AS A START. WILL ALSO MAINTAIN BR WITH VSBYS OF 4-6SM GIVEN SFC DEWPOINTS NOW IN THE MID 60S. THE NEXT ROUND OF CONVECTION WILL BE FROM AFTERNOON INTO EARLY EVENING AS A SURFACE TROUGH MOVES THROUGH THE AREA. WILL MAINTAIN A PERIOD OF SHRAS...BUT FORGO TSRAS GIVEN UNCERTAINTY OF HOW MORNING ACTIVITY WILL EVOLVE (AND MODULATE ANY SUBSEQUENT AFTERNOON RE-FIRING). FOR DTW...LATE NIGHT BR STILL LOOKS TO A DECENT BET GIVEN DEWPOINTS AROUND 65F AND LIGHT SOUTH WINDS OF 5 KNOTS OR LESS. WHILE THERE WILL BE A SMALL CHANCE OF SHRAS EARLY WEDNESDAY...THE NEXT DECENT CHANCE OF SHRAS/TSRAS WILL LIKELY HOLD OFF UNTIL 20Z-22Z AS A TROUGH MOVES INTO THE AREA //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILINGS AOB 5000 FEET WEDNESDAY AFTERNOON. * LOW CONFIDENCE IN TIMING/COVERAGE OF THUNDERSTORMS WEDNESDAY AFTERNOON. && .PREV DISCUSSION...ISSUED 402 PM EDT TUE AUG 6 2013 SHORT TERM...THROUGH TONIGHT CURRENT OBSERVATIONS AND SATELLITE TRENDS SHOW CLOUDS OVER SOUTHEAST MICHIGAN...ALONG WITH RAIN SHOWERS CONTINUING TO MOVE OFF TO THE NORTHEAST. AREAS OF RAIN SHOWERS WERE ABLE TO DEVELOP OVER THE WESTERN CWA AND MAINTAIN MOMENTUM AS AN AREA OF 500 MB VORTICITY MOVED THROUGH AND LOW LEVEL LAPSE RATES INCREASED TO AROUND 6.5 C/KM. A BREAK IN THE RAIN WILL BE SEEN BEFORE ANOTHER ROUND MOVES THROUGH ROUGHLY THE SAME AREA LATE THIS AFTERNOON AND EVENING. LATEST RUN OF THE HRRR IS ADVERTISING MORE SHOWERS BETWEEN 20Z-03Z. HAVE SLIGHTLY INCREASED POPS IN AREAS MAINLY NORTH OF METRO DETROIT DURING THIS TIMEFRAME. EXPECTING MODERATE RAIN SHOWERS AS WAS SEEN THIS MORNING...WITH A SLIGHT CHANCE FOR ISOLATED THUNDERSTORMS. EXPECTING ANY THUNDERSTORMS THAT DO DEVELOP TO REMAIN BELOW SEVERE CRITERIA. HAVE BEEN MONITORING A SMALL BREAK IN CLOUDS OVER THE PAST FEW HOURS WHICH HAS ALLOWED INSTABILITY TO INCREASE. LOOKING AT THE SPC MESOANALYSIS...LOW LEVEL LAPSE RATES HAVE INCREASED TO AROUND 7-7.5 WITH SBCAPE ONLY AROUND 500 J/KG. SHOWERS HAVE STARTED TO DEVELOP JUST SOUTH OF THE LANSING AND WILL CONTINUE TO MOVE OFF TO THE NORTHEAST. CHANCES FOR PRECIPITATION WILL DIMINISH WITH THE LOSS OF DIURNAL HEATING. OVERNIGHT...SOUTHEAST MICHIGAN WILL START FEELING THE INFLUENCE FROM THE UPPER LEVEL JET STREAK AS THE LOW PRESSURE CURRENTLY OVER THE UPPER MIDWEST SAGS EAST. HIGHER CLOUDS FROM CONVECTION CURRENTLY OVER WISCONSIN WILL STREAM IN OVER SE MICHIGAN AND WITH WINDS OUT OF THE SOUTH..WILL KEEP LOWS WARMER THAN THE PREVIOUS MORNING. ANOTHER AREA OF VORTICITY ASSOCIATED AHEAD OF THE COLD FRONT IS SET TO ROTATE DOWN ACROSS THE UPPER GREAT LAKES WEDNESDAY MORNING...INCREASING THE CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS. LONG TERM...WEDNESDAY THROUGH MONDAY NOT MUCH CHANGE IN THE LONG TERM THROUGH THE PERIOD AS THE DOMINATE CUTOFF UPPER LOW CONTINUES TO WOBBLE ABOUT EASTERN CANADA. MODELS HAVE HAD AMPLE TIME TO LATCH ONTO THIS FEATURE WHICH HAS LED TO GOOD AGREEMENT WITH THE OVERALL PATTERN. A SECOND UPPER LOW OVER THE WEST COAST IS STEERING THE SOUTHERN STREAM OF THE JET UP FROM SOUTHERN CALIFORNIA THROUGH THE CENTRAL PORTION OF THE CONUS TO THE GREAT LAKES. THIS WILL BRING ABOUT SOME PHASING OF THE TWO STREAMS OVER THE GREAT LAKES THROUGH THE WEEKEND. GENERAL NW PROGRESSIVE FLOW WILL SEND A SERIES OF SHORTWAVES THROUGH THE REGION PRODUCING A FEW SHOTS AT PRECIP BUT DRY AIR AND HIGH IN THE WAKE OF THE BEST FRONT ON WEDNESDAY WILL PREVENT ANY SIGNIFICANT EVENTS. FOR WEDNESDAY...WE MAY HAVE A COUPLE ROUNDS OF PRECIP IN THE HOPPER AS MODELS INDICATE A MORNING COMPLEX WITH A LEAD SHORTWAVE FOLLOWED BY A SECOND ROUND ALONG THE COLD FRONT ITSELF LATER IN THE AFTERNOON/EVENING. BOTH THE NAM AND HRRR SUGGEST THE MORNING STORM COMPLEX WILL TRACK GENERALLY THROUGH CHI AND IND KEEPING THE BULK OF PRECIP TO OUR SOUTH WITH SOME MORE SCATTERED SHOWERS UP AROUND SE MI. THIS WILL COME MORE IN LINE THROUGH THE EVENING AS WE SEE IF/HOW THE COMPLEX ACTUALLY COMES TOGETHER. REGARDLESS THERE WILL BE A FAIR AMOUNT OF CLOUD COVER TO CONTEND WITH EARLY IN THE DAY. AS IS USUALLY THE CASE FOR THE AREA...THE AMOUNT OF CLOUDS AND HOW LONG THEY STICK AROUND WILL HELP DICTATE WHERE WE STAND WITH CONVECTION LATER IN THE DAY ALONG THE FRONT. EVEN WITH THE NAM KEEPING A FAIR AMOUNT OF CLOUDS AROUND THROUGH THE DAY IT STILL GENERATES UP TO 1500 K/KG OF CAPE WITH 30-40 KNOTS OF BULK SHEAR. GFS IS A LITTLE MORE BULLISH WITH CLEARING WHICH THEN ALLOWS MORE INSTABILITY TO BUILD ADVERTISING JUST OVER 2000 J/KG OF CAPE. ANOTHER PROBLEM WITH THE SETUP IS THAT THE PARENT SFC LOW WILL BE LIFTING TO THE NORTH THROUGH THE DAY WHICH SLOWLY ORIENTATES THE FRONT PARALLEL TO THE FLOW REDUCING SFC CONVERGENCE ALONG THE FRONT. LI/S ARE ON THE LOW SIDE AS WELL ONLY REACHING AROUND -3C. FRONTAL TIMING WILL BE FAVORABLE GIVING SE MI THE FULL DAY TO CLEAR OUT AND HEAT UP BEFORE THE FRONT ROLLS THROUGH SO CHANCES FOR STRONG ORGANIZED STORMS WILL GET LARGER AS YOU TRACK FROM MBS TO DTW. SPC IS ON TRACK WITH THIS THINKING KEEPING ONLY FAR SE MI...SE OF A LINE FROM PORT HURON TO COLDWATER...WITHIN THE SLIGHT RISK AREA. TEMPS SHOULD REACH 80+ FOR MOST LOCATIONS AS A DECENT THETA E RIDGE BUILDS IN AHEAD OF THE FRONT. 850 MB TEMPS ARE STILL PROGGED TO REACH 16C BY THE AFTERNOON HOURS. IN THE WAKE OF THE FRONT A HIGH PRESSURE SYSTEM WILL SLIDE INTO THE REGION BRINGING COOLER DRIER AIR IN FROM CANADA THROUGH SATURDAY. A WEAK FRONT WILL DROP THROUGH FRIDAY NIGHT WITH LITTLE CHANCE OF PRODUCING MORE THAN A CHANCE FOR MOST LOCATIONS. A SHORTWAVE ON SUNDAY WILL WORK OVER THE AREA BUT WILL LIKELY STRUGGLE TO PRODUCE ANY PRECIP WITH DRY AIR PRESENT. NORTHERLY FLOW WITH THE MAIN BAROCLINIC ZONE TO OUR SOUTH WILL KEEP TEMPERATURES ON THE COOL SIDE THROUGH MUCH OF THE EXTENDED. THE PATTERN HAS YIELDED AN EXTENSIVE PERIOD OF 70S AND DO NOT SEE THIS CHANGING. MARINE... LOW PRESSURE WILL SAG OVER THE UPPER GREAT LAKES PULLING A COLD FRONT THROUGH THE AREA LATER WEDNESDAY EVENING. SOUTHERLY WINDS AHEAD OF THE FRONT WILL CONTINUE OVERNIGHT AND THROUGH WEDNESDAY. WARMER AIR ASSOCIATED WITH THE SOUTHERLY WINDS WILL KEEP CONDITIONS STABLE OVER THE WATERS. CHANCE FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS WILL INCREASE STARTING WEDNESDAY MORNING. WINDS WILL DIMINISH THURSDAY INTO FRIDAY AS HIGH PRESSURE OVERSPREADS THE REGION. ANOTHER COLD FRONT IS FORECAST TO TRAVERSE THE LAKES FRIDAY NIGHT. A PUSH OF MUCH COLDER AIR BEHIND THIS FRONT IS LIKELY TO CAUSE STRENGTHENING OF THE POST FRONTAL NORTHWEST WINDS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....DG SHORT TERM...SS LONG TERM....DRK MARINE.......SS YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1137 PM EDT TUE AUG 6 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 347 PM EDT TUE AUG 6 2013 A COLD FRONT WILL MOVE THROUGH THE NORTHERN PLAINS TONIGHT AND APPROACH LAKE MICHIGAN TOWARDS DAYBREAK. THE FRONT WILL SWEEP THROUGH LOWER MICHIGAN ON WEDNESDAY BRINGING COOLER AND DRIER AIR INTO THE REGION FOR WEDNESDAY NIGHT AND THURSDAY. SHOWER AND STORMS WILL ACCOMPANY THE FRONT BOTH TONIGHT AND WEDNESDAY. SOME OF THE STORMS MAY BE ON THE STRONG SIDE WEDNESDAY AFTERNOON SOUTH AND EAST OF GRAND RAPIDS. HIGHS ON WEDNESDAY WILL PUSH INTO THE UPPER 70S AND LOWER 80S. THE UPCOMING WEEKEND LOOKS DRY WITH HIGHS IN THE 70S. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 347 PM EDT TUE AUG 6 2013 MAIN CONCERNS IN THE SHORT TERM ARE RELATED TO CONVECTION TONIGHT AND WEDNESDAY. CURRENT THINKING IS WE WILL SEE SOME SCATTERED SHOWERS AND STORMS BETWEEN NOW AND MIDNIGHT...WITH BETTER CHANCES OCCURRING LATE. THE LATEST HRRR GUIDANCE WOULD SUGGEST WE WILL SEE A THUNDERSTORM COMPLEX ROLL EAST OUT OF WISCONSIN AND MOVE INTO CENTRAL LOWER MICHIGAN OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN THE CONFIGURATION OF THE 850MB LLJ. NOT EXPECTING SEVERE WEATHER AT THIS TIME...BUT THE SIMULATED REFLECTIVITY IS IN THE FORM OF A SQUALL LINE. EXPECT SCATTERED SHOWERS AND STORMS TO BE OVER A DECENT AMOUNT OF THE FORECAST AREA BETWEEN 09Z AND 15Z AS UPSTREAM RESIDUAL CONVECTION SLIDES INTO LOWER MICHIGAN OR DEVELOPS OVERHEAD ON THE LLJ. SHOWERS AND STORMS SHOULD REFOCUS MIDDAY ALONG THE COLD FRONT THAT SHOULD BISECT THE CWA. STRONG STORMS ARE POSSIBLE IN THE EASTERN CWA TOMORROW AFTERNOON WITH 40 KNOTS OF DEEP LAYER SHEAR AND THE POTENTIAL FOR SOME BREAKS IN THE OVERCAST AHEAD OF THE MORNING STORMS. CLOUD COVER TOMORROW MORNING WILL DETERMINE THE STRENGTH OF THE AFTERNOON CONVECTION AS DEEP MOISTURE WILL BE IN PLACE. THE SHOWERS AND STORMS SHOULD EXIT TO THE EAST EARLY IN THE EVENING AS THE FRONT SWEEPS THROUGH. MAINLY DRY WEATHER IS THEN FORECAST FROM WEDNESDAY EVENING THROUGH THURSDAY NIGHT. THERE IS SOME SMALL POTENTIAL FOR SHOWERS AND STORMS IN THE SOUTH THURSDAY NIGHT...BUT THIS ACTIVITY MAY JUST MISS THE AREA TO THE SOUTH PER RECENT MODEL TRENDS. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 347 PM EDT TUE AUG 6 2013 THE POLAR VORTEX OVER EASTERN CANADA WILL CONTINUE TO PLAY A ROLE IN OUR WEATHER THROUGH THE EXTENDED PERIOD. A STRONG SHORT WAVE MOVING ACROSS ONTARIO WILL PUSH A COLD FRONT THROUGH THE CWA FRIDAY SENDING ANOTHER PUSH OF COOLER AIR SOUTH ACROSS THE CWA FOR THE WEEKEND. THE LACK OF DEEP MOISTURE AND INSTABILITY WILL RESULT IN LIGHT SHOWERS AT BEST FRIDAY. MUCH OF THE WEEKEND LOOKS DRY WITH HIGHS IN THE MID 70S AND DEWPOINTS IN THE 50S AS SFC HIGH PRESSURE SETTLES OVER THE GREAT LAKES. ANOTHER SHORT WAVE WILL DROP SOUTH FROM NORTHERN ONTARIO DURING THE MONDAY/TUESDAY TIME FRAME. SIMILAR TO THE LAST FRONT...THERE WON/T BE MUCH MOISTURE WITH THIS FRONT EITHER. LOW CHANCES OF SHOWERS WILL COVER THIS TROUGH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1136 PM EDT TUE AUG 6 2013 THE MAIN QUESTION IS THE CONVECTION OVER EASTERN MINNESOTA AND WESTERN WISCONSIN... CAN IT REACH SOUTHWEST LOWER MICHIGAN BEFORE DISSIPATING? THE HRRR CONTINUES TO SLOW DOWN THE ARRIVAL TIME OF THE CONVECTION INTO SOUTHWEST MICHIGAN. USING THE TIMING TOOL SEVERAL TIME I FIND THE SAME TREND... EVEN WITH THE 45 KNOT SPEED OF THE CONVECTION... IT IS SLOWER EACH TIME I CHECK. AS OF 0330Z IT NOW SUGGESTS MKG AROUND 10Z AND GRR AROUND 11Z AND 12Z FOR AZO AND BTL. SO I SLOWED THE TIMING IN THE TAFS. THE CONVECTION ON THE COLD FRONT SHOULD STILL DEVELOP EAST OF US-131 EARLY TO MID AFTERNOON. IT MAY IMPACT LAN AND JXN MORE SO THAN AZO AND BTL EVEN SO I KEPT THE VCTS IN THOSE TAF SITES... AZO...BTL...LAN AND JXN JUST IN CASE. && .MARINE... ISSUED AT 347 PM EDT TUE AUG 6 2013 HAVE HELD OFF ON ANY SMALL CRAFT ADVISORIES OR BEACH HAZARDS STATEMENTS AS THE WINDS AND WAVES IN TODAY/S MODEL RUNS ARE NOT AS SIGNIFICANT AS LAST NIGHT OR YESTERDAY. IT APPEARS AT THIS POINT IN BOTH THE SOUTHERLY FLOW TONIGHT AND THE NORTH FLOW BEHIND THE FRONT TOMORROW THAT WE REMAIN BELOW CRITERIA. AM A BIT CONCERNED THOUGH BASED ON THE WINDS SEEN IN BUFKIT THAT WE WON/T INDEED BE HIGHER BOTH TONIGHT...WEDNESDAY AND WEDNESDAY NIGHT. WE WILL SEE AS WE PROGRESS THROUGH THE EVENING AS BUFKIT WOULD SUGGEST INCREASING WINDS IN THE 04Z-08Z TIME FRAME. WE PLAY THINGS LOWER AT THIS POINT BUT WATCH CAUTIOUSLY AND CLOSELY. && .HYDROLOGY... ISSUED AT 347 PM EDT TUE AUG 6 2013 NO SIGNIFICANT HYDRO ISSUES EXPECTED THROUGH THE NEXT COUPLE DAYS WITH NEAR NORMAL FLOWS IN PLACE NOW AND FORECAST RAINFALL IS NOT EXPECTED TO BE WIDESPREAD OR OVERLY HEAVY. RAINFALL LAST NIGHT WAS QUITE LIMITED AS WELL SO WE ARE STARTING OFF WITH FAIRLY DRY GROUND OVER MUCH OF THE AREA. RAINFALL IS EXPECTED TONIGHT THROUGH WEDNESDAY...BUT IT WILL BE ASSOCIATED WITH THUNDERSTORM COMPLEXES THAT WILL BE TRAVERSING THE AREA AT A DECENT CLIP. THE FIRST COMES LATE TONIGHT AS STORMS THAT FIRE IN MINNESOTA THIS EVENING TRY TO MOVE ACROSS LAKE MICHIGAN AFTER MIDNIGHT. THESE STORMS WILL LIKELY AFFECT CENTRAL LOWER MICHIGAN. SCATTERED SHOWERS AND STORMS WILL THEN TRAVERSE MUCH OF THE AREA LATE TONIGHT AND WEDNESDAY MORNING. A MORE CONCENTRATED AREA OF SHOWERS AND STORMS WILL AFFECT THE EASTERN TO SOUTHEASTERN HALF OF THE AREA WEDNESDAY AFTERNOON. WE COULD SEE GENERAL RAINFALL AMOUNTS ON THE ORDER OF A QUARTER TO HALF INCH WITH ISOLATED AMOUNTS AROUND AN INCH. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...DUKE SHORT TERM...DUKE LONG TERM...93 AVIATION...WDM HYDROLOGY...DUKE MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
743 PM EDT TUE AUG 6 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 347 PM EDT TUE AUG 6 2013 A COLD FRONT WILL MOVE THROUGH THE NORTHERN PLAINS TONIGHT AND APPROACH LAKE MICHIGAN TOWARDS DAYBREAK. THE FRONT WILL SWEEP THROUGH LOWER MICHIGAN ON WEDNESDAY BRINGING COOLER AND DRIER AIR INTO THE REGION FOR WEDNESDAY NIGHT AND THURSDAY. SHOWER AND STORMS WILL ACCOMPANY THE FRONT BOTH TONIGHT AND WEDNESDAY. SOME OF THE STORMS MAY BE ON THE STRONG SIDE WEDNESDAY AFTERNOON SOUTH AND EAST OF GRAND RAPIDS. HIGHS ON WEDNESDAY WILL PUSH INTO THE UPPER 70S AND LOWER 80S. THE UPCOMING WEEKEND LOOKS DRY WITH HIGHS IN THE 70S. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 347 PM EDT TUE AUG 6 2013 MAIN CONCERNS IN THE SHORT TERM ARE RELATED TO CONVECTION TONIGHT AND WEDNESDAY. CURRENT THINKING IS WE WILL SEE SOME SCATTERED SHOWERS AND STORMS BETWEEN NOW AND MIDNIGHT...WITH BETTER CHANCES OCCURRING LATE. THE LATEST HRRR GUIDANCE WOULD SUGGEST WE WILL SEE A THUNDERSTORM COMPLEX ROLL EAST OUT OF WISCONSIN AND MOVE INTO CENTRAL LOWER MICHIGAN OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN THE CONFIGURATION OF THE 850MB LLJ. NOT EXPECTING SEVERE WEATHER AT THIS TIME...BUT THE SIMULATED REFLECTIVITY IS IN THE FORM OF A SQUALL LINE. EXPECT SCATTERED SHOWERS AND STORMS TO BE OVER A DECENT AMOUNT OF THE FORECAST AREA BETWEEN 09Z AND 15Z AS UPSTREAM RESIDUAL CONVECTION SLIDES INTO LOWER MICHIGAN OR DEVELOPS OVERHEAD ON THE LLJ. SHOWERS AND STORMS SHOULD REFOCUS MIDDAY ALONG THE COLD FRONT THAT SHOULD BISECT THE CWA. STRONG STORMS ARE POSSIBLE IN THE EASTERN CWA TOMORROW AFTERNOON WITH 40 KNOTS OF DEEP LAYER SHEAR AND THE POTENTIAL FOR SOME BREAKS IN THE OVERCAST AHEAD OF THE MORNING STORMS. CLOUD COVER TOMORROW MORNING WILL DETERMINE THE STRENGTH OF THE AFTERNOON CONVECTION AS DEEP MOISTURE WILL BE IN PLACE. THE SHOWERS AND STORMS SHOULD EXIT TO THE EAST EARLY IN THE EVENING AS THE FRONT SWEEPS THROUGH. MAINLY DRY WEATHER IS THEN FORECAST FROM WEDNESDAY EVENING THROUGH THURSDAY NIGHT. THERE IS SOME SMALL POTENTIAL FOR SHOWERS AND STORMS IN THE SOUTH THURSDAY NIGHT...BUT THIS ACTIVITY MAY JUST MISS THE AREA TO THE SOUTH PER RECENT MODEL TRENDS. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 347 PM EDT TUE AUG 6 2013 THE POLAR VORTEX OVER EASTERN CANADA WILL CONTINUE TO PLAY A ROLE IN OUR WEATHER THROUGH THE EXTENDED PERIOD. A STRONG SHORT WAVE MOVING ACROSS ONTARIO WILL PUSH A COLD FRONT THROUGH THE CWA FRIDAY SENDING ANOTHER PUSH OF COOLER AIR SOUTH ACROSS THE CWA FOR THE WEEKEND. THE LACK OF DEEP MOISTURE AND INSTABILITY WILL RESULT IN LIGHT SHOWERS AT BEST FRIDAY. MUCH OF THE WEEKEND LOOKS DRY WITH HIGHS IN THE MID 70S AND DEWPOINTS IN THE 50S AS SFC HIGH PRESSURE SETTLES OVER THE GREAT LAKES. ANOTHER SHORT WAVE WILL DROP SOUTH FROM NORTHERN ONTARIO DURING THE MONDAY/TUESDAY TIME FRAME. SIMILAR TO THE LAST FRONT...THERE WON/T BE MUCH MOISTURE WITH THIS FRONT EITHER. LOW CHANCES OF SHOWERS WILL COVER THIS TROUGH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 742 PM EDT TUE AUG 6 2013 I AM WATCHING FOR THE POTENTIAL THAT A LINE OF THUNDERSTORMS WILL DEVELOP AHEAD OF THE SYSTEM HEADING EAST SOUTHEAST FROM MINNESOTA THIS EVENING. BASED ON TIMING FROM THE HRRR 19Z...20Z AND 21Z RUNS (MODEL VERY CONSISTENT ON TIMING) THE LINE SHOULD REACH THE LAKE SHORE AROUND 08Z NEAR LITTLE SABLE POINT... MKG BY 09Z AND BTL-AZO BY 10Z. I PUT THE STORMS IN THE MKG AND GRR TAF BUT ONLY VCTS FOR THE OTHER TAFS SINCE I AM NOT AS SURE THE LINE WILL HOLD TOGETHER THAT LONG. COULD BE GUSTY WINDS AT MKG AND GRR AS THE LINE MOVES THROUGH. THE HRRR SHOWS GUSTS TO 45 KNOTS BUT THIS TOO FAR OUR IN TIME FOR OUR TAFS FOR THAT SORT OF DETAIL. HOWEVER... IF THE STORMS ACT AS THE HRRR SUGGESTS... I WILL LATER UPDATE THE TAFS TO INCLUDE GUSTY WINDS TO BETTER SHOW THE EXPECTED STORM IMPACTS. ONCE THE STORMS MOVE THROUGH THERE WILL BE SOME CLEARING BEHIND THE LINE. I EXPECT ANOTHER LINE WILL FORM EAST OF US-131 AHEAD OF THE COLD FRONT LATE MORNING AND HEAD EAST ACROSS LAN AND JXN BY EARLY AFTERNOON. ONCE AGAIN I PUT VCTS FOR THIS TOO. && .MARINE... ISSUED AT 347 PM EDT TUE AUG 6 2013 HAVE HELD OFF ON ANY SMALL CRAFT ADVISORIES OR BEACH HAZARDS STATEMENTS AS THE WINDS AND WAVES IN TODAY/S MODEL RUNS ARE NOT AS SIGNIFICANT AS LAST NIGHT OR YESTERDAY. IT APPEARS AT THIS POINT IN BOTH THE SOUTHERLY FLOW TONIGHT AND THE NORTH FLOW BEHIND THE FRONT TOMORROW THAT WE REMAIN BELOW CRITERIA. AM A BIT CONCERNED THOUGH BASED ON THE WINDS SEEN IN BUFKIT THAT WE WON/T INDEED BE HIGHER BOTH TONIGHT...WEDNESDAY AND WEDNESDAY NIGHT. WE WILL SEE AS WE PROGRESS THROUGH THE EVENING AS BUFKIT WOULD SUGGEST INCREASING WINDS IN THE 04Z-08Z TIME FRAME. WE PLAY THINGS LOWER AT THIS POINT BUT WATCH CAUTIOUSLY AND CLOSELY. && .HYDROLOGY... ISSUED AT 347 PM EDT TUE AUG 6 2013 NO SIGNIFICANT HYDRO ISSUES EXPECTED THROUGH THE NEXT COUPLE DAYS WITH NEAR NORMAL FLOWS IN PLACE NOW AND FORECAST RAINFALL IS NOT EXPECTED TO BE WIDESPREAD OR OVERLY HEAVY. RAINFALL LAST NIGHT WAS QUITE LIMITED AS WELL SO WE ARE STARTING OFF WITH FAIRLY DRY GROUND OVER MUCH OF THE AREA. RAINFALL IS EXPECTED TONIGHT THROUGH WEDNESDAY...BUT IT WILL BE ASSOCIATED WITH THUNDERSTORM COMPLEXES THAT WILL BE TRAVERSING THE AREA AT A DECENT CLIP. THE FIRST COMES LATE TONIGHT AS STORMS THAT FIRE IN MINNESOTA THIS EVENING TRY TO MOVE ACROSS LAKE MICHIGAN AFTER MIDNIGHT. THESE STORMS WILL LIKELY AFFECT CENTRAL LOWER MICHIGAN. SCATTERED SHOWERS AND STORMS WILL THEN TRAVERSE MUCH OF THE AREA LATE TONIGHT AND WEDNESDAY MORNING. A MORE CONCENTRATED AREA OF SHOWERS AND STORMS WILL AFFECT THE EASTERN TO SOUTHEASTERN HALF OF THE AREA WEDNESDAY AFTERNOON. WE COULD SEE GENERAL RAINFALL AMOUNTS ON THE ORDER OF A QUARTER TO HALF INCH WITH ISOLATED AMOUNTS AROUND AN INCH. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...DUKE SHORT TERM...DUKE LONG TERM...93 AVIATION...WDM HYDROLOGY...DUKE MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
138 PM EDT MON AUG 5 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 334 AM EDT MON AUG 5 2013 CLOUDS WILL BE ON THE INCREASE THIS MORNING...AND RAIN WILL SPREAD IN ACROSS THE AREA THIS AFTERNOON AND EARLY THIS EVENING. RAIN IS THEN EXPECTED TO REMAIN OVER THE AREA FOR A GOOD PORTION OF THE NIGHT TONIGHT. THERE WILL BE A LOW CHANCE OF A THUNDERSTORM TONIGHT...HOWEVER MOST AREAS WILL NOT SEE ONE AND SEVERE WEATHER IS NOT EXPECTED. ANOTHER BETTER CHANCE OF SHOWERS AND STORMS WILL COME DURING THE TUESDAY NIGHT AND WEDNESDAY TIME FRAME AHEAD OF AND ALONG A COLD FRONT THAT WILL MOVE THROUGH THE AREA. DRIER AIR CAN BE EXPECTED FOR THE END OF THE WEEK. && .UPDATE... ISSUED AT 1153 AM EDT MON AUG 5 2013 BACKED OFF ON THE CHANCES FOR SHOWERS THIS AFTERNOON JUST A BIT. DRIER AIR IS WINNING THE BATTLE AT THE MOMENT WITH MUCH OF THE PRECIP DIMINISHING IN AREAL EXTENT AND INTENSITY AS TO MOVES INTO LOWER MI. THERE MAY BE A DECENT LULL THROUGH THE EARLY TO MID AFTERNOON HOURS. THE EXPECTATION IS THAT WE WILL SEE PRECIPITATION BECOME MORE WIDESPREAD IN THE LATE AFTERNOON THOUGH AND INTO THE EVENING HOURS. THE HRRR SHOWS A LITTTLE LESS PRECIPITATION THAN IT DID A FEW HOURS AGO BUT STILL SHOWS RAIN SHOWERS EXPANDING IN COVERAGE TOWARDS 00Z. SO...CHANCE TYPE POPS FOR RAIN SHOWERS INTO MID AFTERNOON BECOMING LIKELY TOWARDS EVENING. MODELS SHOW A GOOD INFLUX OF MOISTURE IN THE LOWER LEVELS WHICH IS WHY WE EXPECT PRECIP TO EXPAND LATER. 850MB MOISTURE TRANSPORT INCREASES AS DOES ISENTROPIC LIFT ON THE 305K SURFACE LATER THIS AFTERNOON. SOLID LIFT ON THE 305K SURFACE IS SEEN AT 00Z WITH CONDENSATION PRESSURE DEFICITS NEAR 0MB/S. SOME BREAKS IN THE OVERCAST WILL BE POSSIBLE THIS AFTERNOON. THE BREAKS COMBINED WITH A LITTLE LESS PRECIPITATION IS WHY WE HAVE NUDGED HIGH TEMPS UP SLIGHTLY IN ALL AREAS. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 334 AM EDT MON AUG 5 2013 THE TWO MAIN PERIODS OF CONCERN ARE RAIN CHANCES THIS AFTERNOON AND TONIGHT...AND THEN CONVECTIVE POTENTIAL TUE NIGHT AND WED. THE MAIN CHANGES TO THE FCST ARE AN INCREASE IN RAIN CHCS THIS AFTERNOON/ TONIGHT AND ALSO DROPPING TEMPS A BIT TODAY AS A RESULT OF THE HIGHER CONFIDENCE OF THE RAIN. AS MENTIONED ABOVE...CONFIDENCE HAS INCREASED A DECENT AMOUNT THAT MOST OF THE AREA WILL SEE A DECENT RAINFALL LATER THIS AFTERNOON AND TONIGHT. MOST OF THE MODELS HAVE FOLLOWED THE EURO IN BRINGING THE SHORT WAVE NOW ACROSS ERN NORTH DAKOTA AS OF 07Z TOWARD THE CWFA LATER TODAY AND TONIGHT. CONVECTION HAS BLOWN UP ACROSS SRN MN AS EXPECTED THIS MORNING AT THE NOSE OF THE LLJ/MOISTURE TRANSPORT JUST AHEAD OF THE WAVE. THE WAVE IS NOT EXPECTED TO LOSE ITS PUNCH AS QUICKLY...AND THE LLJ/MOISTURE TRANSPORT AXIS WILL SHIFT TO LAKE MICHIGAN BY 00Z. WE WILL LIKELY SEE THE SHOWERS OUT AHEAD OF IT TRAVEL VIA THE FAST MID LEVEL FLOW INTO THE AREA A BIT EARLIER AHEAD OF THE LLJ. IT APPEARS THAT RAIN WILL APPROACH THE COAST BY 18Z...AND SHOULD OVERSPREAD A GOOD MAJORITY OF THE CWFA BY 00Z TONIGHT. FOR THIS REASON...WE BELIEVE TEMPS WILL RISE QUICKLY TO AROUND 70 BY THE TIME THE RAIN MOVES IN...BEFORE FALLING ONCE THE RAIN GET HERE. THE INSTABILITY DOES NOT FOLLOW AS QUICKLY...AND WEAKENS BY THE TIME IT GETS HERE AFTER 03Z TONIGHT AS THE SHORT WAVE BEGINS TO ENTER THE AREA. EVEN WHEN IT DOES ARRIVE...IT WILL LIKELY ONLY PRODUCE ISOLATED STORMS AS LI/S ARE JUST A TOUCH BELOW ZERO C. DUE TO THE LACK OF INSTABILITY BOTH AT THE SFC AND ALOFT...WE DO NOT EXPECT ANY SEVERE WEATHER EVEN WITH GOOD SHEAR VALUES. THE RAIN SHOULD MOVE OUT BY 12Z TUE AS THE SHORT WAVE SHOULD BE READY TO EXIT THE CWFA BY THAT TIME. WE SHOULD SEE A RELATIVE LULL IN PCPN WITH SOME SHORT WAVE RIDGING EXPECTED IN THE WAKE. THE SFC FRONT WILL BE JUST SOUTHWEST OF THE AREA...AND WE COULD SEE WEAK SHORT WAVES IN THE FAST FLOW ALOFT POTENTIALLY TOUCH OFF ADDITIONAL SHOWERS AND STORMS. THE NEXT BEST CHC OF ADDITIONAL SHOWERS AND STORMS WILL COME DURING THE SECOND HALF OF TUE NIGHT AND WED MORNING ACROSS THE AREA. THIS WILL OCCUR AS A BETTER DEFINED SHORT WAVE IS EXPECTED TO DIVE SE OUT OF CANADA AND INTO THE UPPER MIDWEST TUE NIGHT. AHEAD OF THE SHORT WAVE...WE WILL SEE THE LLJ HELP TO FIRE CONVECTION TO OUR WEST NEAR THE QUAD CITIES AND THEN MOVE IN VIA THE MEAN WRLY FLOW ALOFT. IF THINGS EVOLVE THIS WAY...THIS SHOULD LIMIT THE CONVECTIVE/SEVERE POTENTIAL ON WED AS THE FRONT MOVES THROUGH AS IT WILL LIMIT THE HEATING AHEAD OF THE FRONT. CONVECTION WILL REMAIN POSSIBLE INTO WED AFTERNOON BEFORE THE FRONT EXITS BY 00Z THU. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 334 AM EDT MON AUG 5 2013 THE THEME OF SLIGHTLY BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH NEXT WEEKEND AS THE PERSISTENT/LARGE VORTEX REMAINS OVER EASTERN CANADA. WILL GO WITH A DRY FORECAST ON WEDNESDAY NIGHT AND THURSDAY AS CURRENT INDICATIONS ARE THAT THE COLD FRONT WILL BE EAST OF THE AREA WITH HIGH PRESSURE BUILDING IN. THE UPPER LOW WHICH DROPS SOUTH TOWARD THE LAKE SUPERIOR REGION LATE IN THE WEEK SHOULD SEND ANOTHER COLD FRONT THROUGH LWR MI ON FRIDAY NIGHT. HOWEVER AHEAD OF THAT FRONT ON FRIDAY H8 TEMPS NEAR 15C TRY TO SNEAK IN. GIVEN ENOUGH SUNSHINE... WE COULD TOP 80 DEGREES FRIDAY AFTERNOON. WILL CARRY A SLIGHT CHANCE OF RAIN SHOWERS WITH THE COLD FRONT ON FRIDAY NIGHT... ALTHOUGH THE COLD AIR BEHIND IT DOES NOT APPEAR TO LINGER TOO LONG SINCE THE UPPER LOW LIFTS OUT OVER THE WEEKEND AND THE FLOW ALOFT GOES ZONAL AGAIN FOR A FEW DAYS. THAT IMPLIES THAT TEMPERATURES NEXT WEEKEND WILL NOT BE TOO MUCH BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 138 PM EDT MON AUG 5 2013 AN UPPER LEVEL LOW WILL CAUSE SHOWER TO DEVELOP LATE THIS AFTERNOON ACROSS THE CWA. REGIONAL NEPH ANALYSIS SHOWS A SHARP DROP FROM VFR TO MVFR OVER EASTERN/CENTRAL WISCONSIN. LOOK FOR A SIMILAR FALLOFF IN CIGS OVER THE TAF SITES THIS EVENING. LOOKING AT MVFR/IFR FOR MUCH OF THE PERIOD. && .MARINE... ISSUED AT 334 AM EDT MON AUG 5 2013 NO MARINE HEADLINES WILL BE REQUIRED WITH THIS FCST PACKAGE. AFTER A BREAK IN THE WINDS EARLY THIS MORNING...WINDS WILL COME BACK UP A BIT TODAY. THIS TIME THEY WILL HAVE A SRLY COMPONENT TO THEM...OUT AHEAD OF THE NEXT INCOMING SYSTEM. SOME LOCATIONS UP NORTH COULD INITIALLY SEE SOME WINDS UP TO 20 KNOTS. SRN LOCATIONS COULD THEN SEE SOME WINDS APPROACH 20 KNOTS TONIGHT AS THE LOW LEVEL JET PASSES ACROSS THOSE AREAS. WINDS WILL DIMINISH ON TUE...ONLY TO COME UP TUE NIGHT AND EARLY WED AHEAD OF THE NEXT FRONT. && .HYDROLOGY... ISSUED AT 334 AM EDT MON AUG 5 2013 WE ARE NOT EXPECTING ANY FLOODING AT THIS TIME...HOWEVER IT DOES LOOK LIKE THE AREA WILL SEE SOME BENEFICIAL RAINS THIS WEEK THROUGH WED. THE AREA OF RAINFALL EXPECTED THIS AFTERNOON AND TONIGHT ALMOST APPEARS TO BE A GOOD SOAKING RAIN. PRECIPITABLE WATERS COME UP A BIT TO AROUND 1.5 INCHES. THIS IS NOT ABNORMALLY HIGH FOR THIS TIME OF THE YEAR. WE ARE EXPECTING THAT MANY LOCATIONS WILL SEE UP TO 0.75 INCHES OF RAIN THROUGH TONIGHT. THE NEXT BATCH OF RAIN WOULD LIKELY BE TUE NIGHT AND WED AS THE NEXT FRONT APPROACHES THE AREA. RAIN AMOUNTS THEN ARE STILL A BIT UNCERTAIN...BUT SOME HEAVIER DOWNPOURS WILL BE POSSIBLE THEN WITH MORE CONVECTION POSSIBLE COMPARED TO TONIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...DUKE SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MEADE AVIATION...93 HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1153 AM EDT MON AUG 5 2013 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 334 AM EDT MON AUG 5 2013 CLOUDS WILL BE ON THE INCREASE THIS MORNING...AND RAIN WILL SPREAD IN ACROSS THE AREA THIS AFTERNOON AND EARLY THIS EVENING. RAIN IS THEN EXPECTED TO REMAIN OVER THE AREA FOR A GOOD PORTION OF THE NIGHT TONIGHT. THERE WILL BE A LOW CHANCE OF A THUNDERSTORM TONIGHT...HOWEVER MOST AREAS WILL NOT SEE ONE AND SEVERE WEATHER IS NOT EXPECTED. ANOTHER BETTER CHANCE OF SHOWERS AND STORMS WILL COME DURING THE TUESDAY NIGHT AND WEDNESDAY TIME FRAME AHEAD OF AND ALONG A COLD FRONT THAT WILL MOVE THROUGH THE AREA. DRIER AIR CAN BE EXPECTED FOR THE END OF THE WEEK. && .UPDATE... ISSUED AT 1153 AM EDT MON AUG 5 2013 BACKED OFF ON THE CHANCES FOR SHOWERS THIS AFTERNOON JUST A BIT. DRIER AIR IS WINNING THE BATTLE AT THE MOMENT WITH MUCH OF THE PRECIP DIMINISHING IN AREAL EXTENT AND INTENSITY AS TO MOVES INTO LOWER MI. THERE MAY BE A DECENT LULL THROUGH THE EARLY TO MID AFTERNOON HOURS. THE EXPECTATION IS THAT WE WILL SEE PRECIPITATION BECOME MORE WIDESPREAD IN THE LATE AFTERNOON THOUGH AND INTO THE EVENING HOURS. THE HRRR SHOWS A LITTTLE LESS PRECIPITATION THAN IT DID A FEW HOURS AGO BUT STILL SHOWS RAIN SHOWERS EXPANDING IN COVERAGE TOWARDS 00Z. SO...CHANCE TYPE POPS FOR RAIN SHOWERS INTO MID AFTERNOON BECOMING LIKELY TOWARDS EVENING. MODELS SHOW A GOOD INFLUX OF MOISTURE IN THE LOWER LEVELS WHICH IS WHY WE EXPECT PRECIP TO EXPAND LATER. 850MB MOISTURE TRANSPORT INCREASES AS DOES ISENTROPIC LIFT ON THE 305K SURFACE LATER THIS AFTERNOON. SOLID LIFT ON THE 305K SURFACE IS SEEN AT 00Z WITH CONDENSATION PRESSURE DEFICITS NEAR 0MB/S. SOME BREAKS IN THE OVERCAST WILL BE POSSIBLE THIS AFTERNOON. THE BREAKS COMBINED WITH A LITTLE LESS PRECIPITATION IS WHY WE HAVE NUDGED HIGH TEMPS UP SLIGHTLY IN ALL AREAS. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 334 AM EDT MON AUG 5 2013 THE TWO MAIN PERIODS OF CONCERN ARE RAIN CHANCES THIS AFTERNOON AND TONIGHT...AND THEN CONVECTIVE POTENTIAL TUE NIGHT AND WED. THE MAIN CHANGES TO THE FCST ARE AN INCREASE IN RAIN CHCS THIS AFTERNOON/ TONIGHT AND ALSO DROPPING TEMPS A BIT TODAY AS A RESULT OF THE HIGHER CONFIDENCE OF THE RAIN. AS MENTIONED ABOVE...CONFIDENCE HAS INCREASED A DECENT AMOUNT THAT MOST OF THE AREA WILL SEE A DECENT RAINFALL LATER THIS AFTERNOON AND TONIGHT. MOST OF THE MODELS HAVE FOLLOWED THE EURO IN BRINGING THE SHORT WAVE NOW ACROSS ERN NORTH DAKOTA AS OF 07Z TOWARD THE CWFA LATER TODAY AND TONIGHT. CONVECTION HAS BLOWN UP ACROSS SRN MN AS EXPECTED THIS MORNING AT THE NOSE OF THE LLJ/MOISTURE TRANSPORT JUST AHEAD OF THE WAVE. THE WAVE IS NOT EXPECTED TO LOSE ITS PUNCH AS QUICKLY...AND THE LLJ/MOISTURE TRANSPORT AXIS WILL SHIFT TO LAKE MICHIGAN BY 00Z. WE WILL LIKELY SEE THE SHOWERS OUT AHEAD OF IT TRAVEL VIA THE FAST MID LEVEL FLOW INTO THE AREA A BIT EARLIER AHEAD OF THE LLJ. IT APPEARS THAT RAIN WILL APPROACH THE COAST BY 18Z...AND SHOULD OVERSPREAD A GOOD MAJORITY OF THE CWFA BY 00Z TONIGHT. FOR THIS REASON...WE BELIEVE TEMPS WILL RISE QUICKLY TO AROUND 70 BY THE TIME THE RAIN MOVES IN...BEFORE FALLING ONCE THE RAIN GET HERE. THE INSTABILITY DOES NOT FOLLOW AS QUICKLY...AND WEAKENS BY THE TIME IT GETS HERE AFTER 03Z TONIGHT AS THE SHORT WAVE BEGINS TO ENTER THE AREA. EVEN WHEN IT DOES ARRIVE...IT WILL LIKELY ONLY PRODUCE ISOLATED STORMS AS LI/S ARE JUST A TOUCH BELOW ZERO C. DUE TO THE LACK OF INSTABILITY BOTH AT THE SFC AND ALOFT...WE DO NOT EXPECT ANY SEVERE WEATHER EVEN WITH GOOD SHEAR VALUES. THE RAIN SHOULD MOVE OUT BY 12Z TUE AS THE SHORT WAVE SHOULD BE READY TO EXIT THE CWFA BY THAT TIME. WE SHOULD SEE A RELATIVE LULL IN PCPN WITH SOME SHORT WAVE RIDGING EXPECTED IN THE WAKE. THE SFC FRONT WILL BE JUST SOUTHWEST OF THE AREA...AND WE COULD SEE WEAK SHORT WAVES IN THE FAST FLOW ALOFT POTENTIALLY TOUCH OFF ADDITIONAL SHOWERS AND STORMS. THE NEXT BEST CHC OF ADDITIONAL SHOWERS AND STORMS WILL COME DURING THE SECOND HALF OF TUE NIGHT AND WED MORNING ACROSS THE AREA. THIS WILL OCCUR AS A BETTER DEFINED SHORT WAVE IS EXPECTED TO DIVE SE OUT OF CANADA AND INTO THE UPPER MIDWEST TUE NIGHT. AHEAD OF THE SHORT WAVE...WE WILL SEE THE LLJ HELP TO FIRE CONVECTION TO OUR WEST NEAR THE QUAD CITIES AND THEN MOVE IN VIA THE MEAN WRLY FLOW ALOFT. IF THINGS EVOLVE THIS WAY...THIS SHOULD LIMIT THE CONVECTIVE/SEVERE POTENTIAL ON WED AS THE FRONT MOVES THROUGH AS IT WILL LIMIT THE HEATING AHEAD OF THE FRONT. CONVECTION WILL REMAIN POSSIBLE INTO WED AFTERNOON BEFORE THE FRONT EXITS BY 00Z THU. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 334 AM EDT MON AUG 5 2013 THE THEME OF SLIGHTLY BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH NEXT WEEKEND AS THE PERSISTENT/LARGE VORTEX REMAINS OVER EASTERN CANADA. WILL GO WITH A DRY FORECAST ON WEDNESDAY NIGHT AND THURSDAY AS CURRENT INDICATIONS ARE THAT THE COLD FRONT WILL BE EAST OF THE AREA WITH HIGH PRESSURE BUILDING IN. THE UPPER LOW WHICH DROPS SOUTH TOWARD THE LAKE SUPERIOR REGION LATE IN THE WEEK SHOULD SEND ANOTHER COLD FRONT THROUGH LWR MI ON FRIDAY NIGHT. HOWEVER AHEAD OF THAT FRONT ON FRIDAY H8 TEMPS NEAR 15C TRY TO SNEAK IN. GIVEN ENOUGH SUNSHINE... WE COULD TOP 80 DEGREES FRIDAY AFTERNOON. WILL CARRY A SLIGHT CHANCE OF RAIN SHOWERS WITH THE COLD FRONT ON FRIDAY NIGHT... ALTHOUGH THE COLD AIR BEHIND IT DOES NOT APPEAR TO LINGER TOO LONG SINCE THE UPPER LOW LIFTS OUT OVER THE WEEKEND AND THE FLOW ALOFT GOES ZONAL AGAIN FOR A FEW DAYS. THAT IMPLIES THAT TEMPERATURES NEXT WEEKEND WILL NOT BE TOO MUCH BELOW NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 754 AM EDT MON AUG 5 2013 SHOWERS APPROACHING FROM WISCONSIN AND MINNESOTA SHOULD OVERSPREAD THE REGION FROM WEST TO EAST AFTER 18Z THIS AFTERNOON. FLIGHT CONDITIONS ARE EXPECTED TO REMAIN VFR WITH CIGS FALLING TO 4000-6000 FT AND VSBYS MOSTLY GREATER THAN 6 MILES AS THE SHOWERS ARRIVE. HOWEVER TONIGHT CONDITIONS SHOULD TREND DOWN INTO MVFR CATEGORY AFTER 03Z AS THE RAIN CONTINUES WITH THE WARM FRONT LIFTING NORTH TOWARD SRN LWR MI. SOME IFR IS ALSO POSSIBLE AFTER 06Z AS HIGHER DEW POINT AIR ASSOCIATED WITH THE WARM FRONT TRIES TO NUDGE IN FROM THE SOUTHWEST. TSTMS ARE VERY UNLIKELY TODAY INTO THE EARLY EVENING ALTHOUGH THAT CHANCE DOES CREEP UP TOWARD 06Z. DID NOT PUT ANY TSTMS IN THE TAFS AT THIS POINT BUT THIS WILL NEED TO BE MONITORED. && .MARINE... ISSUED AT 334 AM EDT MON AUG 5 2013 NO MARINE HEADLINES WILL BE REQUIRED WITH THIS FCST PACKAGE. AFTER A BREAK IN THE WINDS EARLY THIS MORNING...WINDS WILL COME BACK UP A BIT TODAY. THIS TIME THEY WILL HAVE A SRLY COMPONENT TO THEM...OUT AHEAD OF THE NEXT INCOMING SYSTEM. SOME LOCATIONS UP NORTH COULD INITIALLY SEE SOME WINDS UP TO 20 KNOTS. SRN LOCATIONS COULD THEN SEE SOME WINDS APPROACH 20 KNOTS TONIGHT AS THE LOW LEVEL JET PASSES ACROSS THOSE AREAS. WINDS WILL DIMINISH ON TUE...ONLY TO COME UP TUE NIGHT AND EARLY WED AHEAD OF THE NEXT FRONT. && .HYDROLOGY... ISSUED AT 334 AM EDT MON AUG 5 2013 WE ARE NOT EXPECTING ANY FLOODING AT THIS TIME...HOWEVER IT DOES LOOK LIKE THE AREA WILL SEE SOME BENEFICIAL RAINS THIS WEEK THROUGH WED. THE AREA OF RAINFALL EXPECTED THIS AFTERNOON AND TONIGHT ALMOST APPEARS TO BE A GOOD SOAKING RAIN. PRECIPITABLE WATERS COME UP A BIT TO AROUND 1.5 INCHES. THIS IS NOT ABNORMALLY HIGH FOR THIS TIME OF THE YEAR. WE ARE EXPECTING THAT MANY LOCATIONS WILL SEE UP TO 0.75 INCHES OF RAIN THROUGH TONIGHT. THE NEXT BATCH OF RAIN WOULD LIKELY BE TUE NIGHT AND WED AS THE NEXT FRONT APPROACHES THE AREA. RAIN AMOUNTS THEN ARE STILL A BIT UNCERTAIN...BUT SOME HEAVIER DOWNPOURS WILL BE POSSIBLE THEN WITH MORE CONVECTION POSSIBLE COMPARED TO TONIGHT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...DUKE SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1259 PM CDT MON AUG 5 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT MON AUG 5 2013 A 30 KT LLJ NOSING UP INTO SW MN EARLY THIS MORNING HAS FORCED A FAIRLY BROAD SHIELD OF SHOWERS WITH EMBEDDED THUNDERSTORMS THAT HAS BEEN STEADILY MAKING ITS WAY ACROSS MN THIS MORNING. ELEVATED INSTABILITY HAS NOT MADE MUCH PROGRESS NE THOUGH...WHICH IS WHY ANY DEEPER CONVECTION HAS ESSENTIALLY BEEN CRAWLING AROUND THE MPX CWA BORDER WITH FSD. MOST OF THE HOPWRF MEMBERS ALONG WITH THE LOCAL MPX-WRF HAVE ALL DONE A DECENT JOB IN CAPTURING WHAT HAS HAPPENED SO FAR OVERNIGHT IN TERMS PRECIP PLACEMENT...THEY HAVE ALL JUST BEEN ABOUT 2 HOURS BEHIND SCHEDULE. AS A RESULT...WAS FAIRLY AGGRESSIVE WITH MOVING LIKELY OR BETTER POPS OUT OF THE AREA THIS MORNING. BASED ON CURRENT MOVEMENT...BACK EDGE OF THE SHOWERS OVER CENTRAL MN WILL BE CLEARING THE EAU AREA AROUND 11Z...SO CERTAINLY DOES NOT MAKE MUCH SENSE TO HAVE MUCH IN THE WAY OF POPS BEYOND 15Z. THE ONLY POTENTIAL PROBLEM FOR THIS FASTER PROGRESSION OF LOWER POPS THROUGH THE AREA IS THE FACT THAT THERE IS A SFC TROUGH/COLD FRONT FEATURE CURRENTLY MOVING THROUGH THE ERN DAKOTAS THAT THE HRRR IS TRYING TO DEVELOP ANOTHER LINE OF CONVECTION ALONG LATER THIS MORNING. HAVE SEEN A FEW SPECKLES ON THE RADAR TO THE WEST OF THE MAIN PRECIP SHIELD OVER WRN MN...BUT TO THIS POINT WE HAVE NOT SEEN ANYTHING TO SUGGEST STORMS ON THE ORDER OF THE WHAT THE 5Z AND 6Z VERSIONS OF THE HRRR HAVE BEEN SHOWING DEVELOPING NEAR THE MN/SD. WITH MAIN PUSH OF MOISTURE TRANSPORT FOLLOWING THE PRECIP SHIELD EAST AND WITH AT LEAST SOME DEGREE OF OVERTURNING OCCURRING WITH THE FIRST ROUND OF RAIN...HAVE FAVORED THE FASTER DEPARTURE OF PRECIP...THOUGH THIS MAY NEED TO BE CHANGED BEFORE RUNNING OUT THE DOOR AT 6 AM. FOR THIS AFTERNOON...BIG CHANGE TO THE FORECAST WAS TO BOOST HIGHS A FEW DEGREES...MAINLY OVER MN. BASED ON THE HOPWRF...ALONG WITH THE RAP...EXPECT SKIES TO OPEN UP PRETTY GOOD BY THIS AFTERNOON BEHIND THIS MORNINGS ACTIVITY. WITH H85 TEMPS IN THE NEIGHBORHOOD OF 16C...THIS WOULD FAVOR MIXING DOWN HIGHS INTO THE LOW TO MID 80S ACROSS MN. HELD HIGHS IN THE 70S ACROSS WI WHERE CLOUD COVER WILL BE MORE PERSISTENT. OF COURSE IF THE CLOUDS DO NOT CLEAR OUT AS PLANNED...THEN IT WILL BE A SECOND DAY IN A ROW WHERE CLOUDS RESULT IN A FORECAST THAT IS A BIT OVERDONE ON THE HIGHS.... FOR THIS AFTERNOON...THAT AFOREMENTIONED DAKOTAS THROUGH WILL MEANDER OVER TO NEAR THE MN/WI BORDER. THE GFS DEVELOPS UP TO 1000 J/KG OF MLCAPE OUT AHEAD OF THIS BOUNDARY...WHICH MAY BE ENOUGH TO GENERATE SOME ISO/SCT STORMS. HOWEVER...BEHIND THIS MORNINGS WAVE...ALL MODELS SHOW SOME PRETTY EXTENSIVE DRYING AND SUBSIDENCE IN THE MID-LEVELS. NAM/RAP SOUNDINGS SHOW A DECENT SUBSIDENCE INVERSION DEVELOPING AROUND H7 AS WELL. ALL OF THIS POINTS TO WHAT SHOULD BE A DRY DAY...THOUGH WITH INSTABILITY FORECAST TO BE IN PLACE...CAN NOT COMPLETELY RULE OUT SOME DIURNALLY DRIVEN THUNDERSTORM ACTIVITY DEVELOPING...SO HAVE LEFT SOME 20-30 POPS IN PLACE THIS AFTERNOON FOR ERN MN INTO WRN WI. FOR TONIGHT...THE MPX AREA LOOKS TO BE CAUGHT BETWEEN AREAS OF FORCING FOR PRECIP...WITH CURRENT PRECIPITATION HEADING FOR MICHIGAN AND THE FRONT FOR TUESDAY AFTERNOON REMAINING FAR ENOUGH NW TO KEEP THE AREA DRY. AT THE MOMENT...EXPECT MAINLY CLEAR SKIES TONIGHT...WITH LIGHT AND VARIABLE WINDS. WITH DEWPS UP IN THE UPPER 50S TO MID 60S...THIS COULD LEAD TO SOME POCKETS OF FOG DEVELOPING OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 330 AM CDT MON AUG 5 2013 THE MAIN FORECAST CONCERN DURING THE TUESDAY THROUGH SUNDAY PERIOD WILL BE THE CHANCES FOR SHRA/TSRA TUESDAY AFTERNOON INTO TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH THE REGION. THE REMAINS SOME VARIABILITY IN THE TIMING AND ORIENTATION OF THE FRONT AMONGST THE GFS... NAM... ECMWF... AND SREF... WITH THE NAM BEING FASTEST AND ECMWF BEING SLOWEST. A SHORTWAVE ROTATING EAST FROM THE NORTHERN ROCKIES WILL HELP DRIVE THE FRONT ACROSS THE AREA WHILE THE MAIN UPPER TROUGH DROPS SOUTH FROM CANADA. LARGE SCALE FORCING IN TERMS OF UPPER DIVERGENCE AND DPVA LOOK SUFFICIENT FOR FAIRLY WIDESPREAD PCPN TO OCCUR ALONG/AHEAD OF THE FRONT... WITH THALER QG DIAGNOSTICS DEPICTING AN ELONGATED AREA OF GOOD 700MB OMEGA FROM WESTERN LAKE SUPERIOR INTO NORTHWEST IOWA BY 00Z WEDNESDAY. THIS SHOULD BE MORE THAN SUFFICIENT TO GET SHRA/TSRA GOING DURING THE AFTERNOON HOURS AS THE FRONT MOVES THROUGH THE AREA. THE QUESTION THEN BECOMES WHETHER OR NOT ANY SEVERE WEATHER CAN BE EXPECTED. THE NEW DAY 2 OUTLOOK FROM SPC DOES INCLUDE A SLIGHT RISK ACROSS MOST OF THE AREA... ESSENTIALLY NEAR AND SOUTH OF I-94. IT LOOKS LIKE WE/LL HAVE ANYWHERE FROM 1000-2000 J/KG OF MLCAPE WITH WHICH TO WORK... ALONG WITH DEEP LAYER SHEAR AOA 40 KT... SO SOME ORGANIZED CONVECTION IS CERTAINLY POSSIBLE. DEEP LAYER SHEAR WILL BE SUFFICIENT FOR SUPERCELLS... BUT WOULDN/T EXPECT THE MODE TO REMAIN DISCRETE FOR VERY LONG GIVEN THE EXPECTATION FOR SOMEWHAT WIDESPREAD DEVELOPMENT. SO... CURRENT EXPECTATIONS WOULD BE FOR INITIAL SUPERCELLS TO QUICKLY TRANSITION INTO CLUSTERS AND A LINEAR SYSTEM WITH TIME. LOW LEVEL SHEAR DOESN/T LOOK TO BE TOO SIGNIFICANT... LIKELY AOB 15-20KT... WHICH SHOULD KEEP TORNADOES FROM BEING MUCH OF A THREAT... LEAVING LARGE HAIL AND WIND AS THE MAIN POTENTIAL ISSUES. THE FRONT SHOULD PUSH THROUGH THE REMAINDER OF THE FORECAST AREA TUESDAY NIGHT... WITH DRY WEATHER AND COOLER TEMPERATURES ON WEDNESDAY AS CANADIAN HIGH PRESSURE BUILDS INTO THE AREA. THE NEXT CHANCE FOR PCPN LOOKS TO HOLD OFF UNTIL THURSDAY AFTERNOON AND THURSDAY NIGHT... WHEN THE MAIN UPPER LOW OVER CENTRAL CANADA DROPS SOUTH TOWARD THE INTERNATIONAL BORDER AND ANOTHER COLD FRONT PUSHES ACROSS THE REGION. MOISTURE RETURN WILL BE LIMITED AHEAD OF THE FRONT... BUT WILL BE SUFFICIENT GIVEN DECENT FORCING FOR SOME SHRA/TSRA. KEPT THINGS MAINLY DRY FROM FRIDAY THROUGH SUNDAY WITH THE EXPECTATION THAT AN EXPANSIVE HIGH WILL BUILD IN FROM CANADA. HOWEVER... IT SHOULD BE NOTED THAT THE 00Z ECMWF IS MORE PROGRESSIVE THAN THE GFS WITH THE UPPER PATTERN AND MANAGES TO FLATTEN THE FLOW OVER THE NORTH CENTRAL CONUS AND BRINGS A SURFACE LOW ACROSS MINNESOTA ON SUNDAY WITH DECENT FRONTOGENESIS AND AN ACCOMPANYING SLUG OF PCPN. STUCK CLOSER TO THE PREVIOUS FORECAST AND GFS AT THIS POINT... AND JUST INCLUDED SOME CHANCE POPS OVER THE SOUTHWEST PORTION OF THE CWFA ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1246 PM CDT MON AUG 5 2013 MVFR CIGS OVER MUCH OF THE REGION WITH ABUNDANT LOW LEVEL MOISTURE REMAINING IN THE WAKE OF THE OVERNIGHT/EARLY MORNING MCS. THIS SHOULD GRADUALLY LIFT THIS AFTERNOON...CLEARING OUT DURING THE EVENING. EXPECT CLOUDS TO LINGER LONGEST OVER THE NORTH AND EAST. SOME THREAT OF CONVECTION REFIRING INTO THE AFTERNOON ACROSS MAINLY WESTERN WI. THIS IS EXPECTED TO BE ISOLATED IT IT DOES REGENERATE...AND SHOULD WANE BY EARLY EVENING. WHERE CLOUD CLEAR OUT...SOME POSSIBILITY OF FOG FORMING LATE...MAINLY TO THE EAST AND SOUTH. WILL CONTINUE TO MENTION LIFR FOG AT KEAU AND SOME FOG AT KRNH. OTHER PROBLEM IS THE TIMING OF INCOMING COLD FRONT...WHICH WILL AFFECT KAXN REGION BEFORE 18Z...AND THEREAFTER ACROSS THE REST OF THE AREA. WILL MENTION VCSH THERE AFTER 15Z FOR NOW. SOUTH WINDS BECOMING NORTHWEST WITH TROUGH PASSAGE THIS AFTERNOON...AND BECOMING LIGHT/VRBL OVER MUCH OF THE AREA INTO TONIGHT. EXPECT WINDS TO BECOME SOUTHERLY AGAIN AHEAD OF THE COLD FRONT TUESDAY MORNING. KMSP...MVFR CIGS TO LIFT TO VFR THIS AFTERNOON...AND CLEARING INTO TONIGHT. EXPECT ANY CONVECTION THAT REDEVELOPS TO BE ISOLATED AND MAINLY EAST OF THE AREA...SO LEFT OUT OF TAF. SOME POSSIBILITY OF FOG FORMING IN THE RIVER VALLEYS LATER TONIGHT...WITH LIGHT WINDS AND LEFTOVER MOISTURE. DONT BELIEVE IT WILL BE WIDESPREAD ENOUGH TO INCLUDE IN THE TAF AT THE MOMENT. TIMING OF FRONT INTO TUESDAY AFTERNOON/EVENING IS THE OTHER PROBLEM. AFTER COLLABORATING WITH CWSU...DECIDED TO MENTION A PROB30 TSRA AFTER 21Z. WINDS WILL BE SOUTH TURING SOUTHWEST EARLY THIS AFTERNOON...THEN NORTHWEST LATE AFTERNOON INTO THE EVENING AS A WEAK TROUGH MOVES THROUGH. SHOULD SEE LIGHT WINDS OVERNIGHT AND SOUTHERLY AHEAD OF THE FRONT ON TUESDAY. /OUTLOOK FOR KMSP/ TUE...TSRA LIKELY AFTERNOON/EVENING. VFR OUTSIDE OF TSRA. WINDS WSW 5-10KTS...BCMG NW OVERNIGHT. WED...VFR. WINDS NW 10 KTS. THU...VFR. CHC TSRA OVERNIGHT. WINDS SW 5 KTS. && $$ SHORT TERM...MPG LONG TERM... AVIATION...DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
559 AM CDT MON AUG 5 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT MON AUG 5 2013 A 30 KT LLJ NOSING UP INTO SW MN EARLY THIS MORNING HAS FORCED A FAIRLY BROAD SHIELD OF SHOWERS WITH EMBEDDED THUNDERSTORMS THAT HAS BEEN STEADILY MAKING ITS WAY ACROSS MN THIS MORNING. ELEVATED INSTABILITY HAS NOT MADE MUCH PROGRESS NE THOUGH...WHICH IS WHY ANY DEEPER CONVECTION HAS ESSENTIALLY BEEN CRAWLING AROUND THE MPX CWA BORDER WITH FSD. MOST OF THE HOPWRF MEMBERS ALONG WITH THE LOCAL MPX-WRF HAVE ALL DONE A DECENT JOB IN CAPTURING WHAT HAS HAPPENED SO FAR OVERNIGHT IN TERMS PRECIP PLACEMENT...THEY HAVE ALL JUST BEEN ABOUT 2 HOURS BEHIND SCHEDULE. AS A RESULT...WAS FAIRLY AGGRESSIVE WITH MOVING LIKELY OR BETTER POPS OUT OF THE AREA THIS MORNING. BASED ON CURRENT MOVEMENT...BACK EDGE OF THE SHOWERS OVER CENTRAL MN WILL BE CLEARING THE EAU AREA AROUND 11Z...SO CERTAINLY DOES NOT MAKE MUCH SENSE TO HAVE MUCH IN THE WAY OF POPS BEYOND 15Z. THE ONLY POTENTIAL PROBLEM FOR THIS FASTER PROGRESSION OF LOWER POPS THROUGH THE AREA IS THE FACT THAT THERE IS A SFC TROUGH/COLD FRONT FEATURE CURRENTLY MOVING THROUGH THE ERN DAKOTAS THAT THE HRRR IS TRYING TO DEVELOP ANOTHER LINE OF CONVECTION ALONG LATER THIS MORNING. HAVE SEEN A FEW SPECKLES ON THE RADAR TO THE WEST OF THE MAIN PRECIP SHIELD OVER WRN MN...BUT TO THIS POINT WE HAVE NOT SEEN ANYTHING TO SUGGEST STORMS ON THE ORDER OF THE WHAT THE 5Z AND 6Z VERSIONS OF THE HRRR HAVE BEEN SHOWING DEVELOPING NEAR THE MN/SD. WITH MAIN PUSH OF MOISTURE TRANSPORT FOLLOWING THE PRECIP SHIELD EAST AND WITH AT LEAST SOME DEGREE OF OVERTURNING OCCURRING WITH THE FIRST ROUND OF RAIN...HAVE FAVORED THE FASTER DEPARTURE OF PRECIP...THOUGH THIS MAY NEED TO BE CHANGED BEFORE RUNNING OUT THE DOOR AT 6 AM. FOR THIS AFTERNOON...BIG CHANGE TO THE FORECAST WAS TO BOOST HIGHS A FEW DEGREES...MAINLY OVER MN. BASED ON THE HOPWRF...ALONG WITH THE RAP...EXPECT SKIES TO OPEN UP PRETTY GOOD BY THIS AFTERNOON BEHIND THIS MORNINGS ACTIVITY. WITH H85 TEMPS IN THE NEIGHBORHOOD OF 16C...THIS WOULD FAVOR MIXING DOWN HIGHS INTO THE LOW TO MID 80S ACROSS MN. HELD HIGHS IN THE 70S ACROSS WI WHERE CLOUD COVER WILL BE MORE PERSISTENT. OF COURSE IF THE CLOUDS DO NOT CLEAR OUT AS PLANNED...THEN IT WILL BE A SECOND DAY IN A ROW WHERE CLOUDS RESULT IN A FORECAST THAT IS A BIT OVERDONE ON THE HIGHS.... FOR THIS AFTERNOON...THAT AFOREMENTIONED DAKOTAS THROUGH WILL MEANDER OVER TO NEAR THE MN/WI BORDER. THE GFS DEVELOPS UP TO 1000 J/KG OF MLCAPE OUT AHEAD OF THIS BOUNDARY...WHICH MAY BE ENOUGH TO GENERATE SOME ISO/SCT STORMS. HOWEVER...BEHIND THIS MORNINGS WAVE...ALL MODELS SHOW SOME PRETTY EXTENSIVE DRYING AND SUBSIDENCE IN THE MID-LEVELS. NAM/RAP SOUNDINGS SHOW A DECENT SUBSIDENCE INVERSION DEVELOPING AROUND H7 AS WELL. ALL OF THIS POINTS TO WHAT SHOULD BE A DRY DAY...THOUGH WITH INSTABILITY FORECAST TO BE IN PLACE...CAN NOT COMPLETELY RULE OUT SOME DIURNALLY DRIVEN THUNDERSTORM ACTIVITY DEVELOPING...SO HAVE LEFT SOME 20-30 POPS IN PLACE THIS AFTERNOON FOR ERN MN INTO WRN WI. FOR TONIGHT...THE MPX AREA LOOKS TO BE CAUGHT BETWEEN AREAS OF FORCING FOR PRECIP...WITH CURRENT PRECIPITATION HEADING FOR MICHIGAN AND THE FRONT FOR TUESDAY AFTERNOON REMAINING FAR ENOUGH NW TO KEEP THE AREA DRY. AT THE MOMENT...EXPECT MAINLY CLEAR SKIES TONIGHT...WITH LIGHT AND VARIABLE WINDS. WITH DEWPS UP IN THE UPPER 50S TO MID 60S...THIS COULD LEAD TO SOME POCKETS OF FOG DEVELOPING OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 330 AM CDT MON AUG 5 2013 THE MAIN FORECAST CONCERN DURING THE TUESDAY THROUGH SUNDAY PERIOD WILL BE THE CHANCES FOR SHRA/TSRA TUESDAY AFTERNOON INTO TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH THE REGION. THE REMAINS SOME VARIABILITY IN THE TIMING AND ORIENTATION OF THE FRONT AMONGST THE GFS... NAM... ECMWF... AND SREF... WITH THE NAM BEING FASTEST AND ECMWF BEING SLOWEST. A SHORTWAVE ROTATING EAST FROM THE NORTHERN ROCKIES WILL HELP DRIVE THE FRONT ACROSS THE AREA WHILE THE MAIN UPPER TROUGH DROPS SOUTH FROM CANADA. LARGE SCALE FORCING IN TERMS OF UPPER DIVERGENCE AND DPVA LOOK SUFFICIENT FOR FAIRLY WIDESPREAD PCPN TO OCCUR ALONG/AHEAD OF THE FRONT... WITH THALER QG DIAGNOSTICS DEPICTING AN ELONGATED AREA OF GOOD 700MB OMEGA FROM WESTERN LAKE SUPERIOR INTO NORTHWEST IOWA BY 00Z WEDNESDAY. THIS SHOULD BE MORE THAN SUFFICIENT TO GET SHRA/TSRA GOING DURING THE AFTERNOON HOURS AS THE FRONT MOVES THROUGH THE AREA. THE QUESTION THEN BECOMES WHETHER OR NOT ANY SEVERE WEATHER CAN BE EXPECTED. THE NEW DAY 2 OUTLOOK FROM SPC DOES INCLUDE A SLIGHT RISK ACROSS MOST OF THE AREA... ESSENTIALLY NEAR AND SOUTH OF I-94. IT LOOKS LIKE WE/LL HAVE ANYWHERE FROM 1000-2000 J/KG OF MLCAPE WITH WHICH TO WORK... ALONG WITH DEEP LAYER SHEAR AOA 40 KT... SO SOME ORGANIZED CONVECTION IS CERTAINLY POSSIBLE. DEEP LAYER SHEAR WILL BE SUFFICIENT FOR SUPERCELLS... BUT WOULDN/T EXPECT THE MODE TO REMAIN DISCRETE FOR VERY LONG GIVEN THE EXPECTATION FOR SOMEWHAT WIDESPREAD DEVELOPMENT. SO... CURRENT EXPECTATIONS WOULD BE FOR INITIAL SUPERCELLS TO QUICKLY TRANSITION INTO CLUSTERS AND A LINEAR SYSTEM WITH TIME. LOW LEVEL SHEAR DOESN/T LOOK TO BE TOO SIGNIFICANT... LIKELY AOB 15-20KT... WHICH SHOULD KEEP TORNADOES FROM BEING MUCH OF A THREAT... LEAVING LARGE HAIL AND WIND AS THE MAIN POTENTIAL ISSUES. THE FRONT SHOULD PUSH THROUGH THE REMAINDER OF THE FORECAST AREA TUESDAY NIGHT... WITH DRY WEATHER AND COOLER TEMPERATURES ON WEDNESDAY AS CANADIAN HIGH PRESSURE BUILDS INTO THE AREA. THE NEXT CHANCE FOR PCPN LOOKS TO HOLD OFF UNTIL THURSDAY AFTERNOON AND THURSDAY NIGHT... WHEN THE MAIN UPPER LOW OVER CENTRAL CANADA DROPS SOUTH TOWARD THE INTERNATIONAL BORDER AND ANOTHER COLD FRONT PUSHES ACROSS THE REGION. MOISTURE RETURN WILL BE LIMITED AHEAD OF THE FRONT... BUT WILL BE SUFFICIENT GIVEN DECENT FORCING FOR SOME SHRA/TSRA. KEPT THINGS MAINLY DRY FROM FRIDAY THROUGH SUNDAY WITH THE EXPECTATION THAT AN EXPANSIVE HIGH WILL BUILD IN FROM CANADA. HOWEVER... IT SHOULD BE NOTED THAT THE 00Z ECMWF IS MORE PROGRESSIVE THAN THE GFS WITH THE UPPER PATTERN AND MANAGES TO FLATTEN THE FLOW OVER THE NORTH CENTRAL CONUS AND BRINGS A SURFACE LOW ACROSS MINNESOTA ON SUNDAY WITH DECENT FRONTOGENESIS AND AN ACCOMPANYING SLUG OF PCPN. STUCK CLOSER TO THE PREVIOUS FORECAST AND GFS AT THIS POINT... AND JUST INCLUDED SOME CHANCE POPS OVER THE SOUTHWEST PORTION OF THE CWFA ON SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 559 AM CDT MON AUG 5 2013 TURNING OUT TO BE QUITE THE UGLY AVIATION MORNING OUT THERE...AS IFR/MVFR CIGS ARE FILLING IN ACROSS THE AREA IN THE WAKE OF THE RAIN SHIELD NOW MOVING INTO IOWA/WI. IN ADDITION...SOME REMNANT MOISTURE TRANSPORT AND WAA HAS ALLOWED SHOWERS TO REDEVELOP FROM THE TWIN CITIES BACK TO RWF...FURTHER AIDING THE CAUSE OF THE LOW CIGS. FOLLOWED THE IDEA OF THE HOPWRF FOR CIGS...WITH A CLEARING RAPIDLY WORKING FROM WEST TO EAST ACROSS THE AREA BETWEEN 15Z AND 21Z. FOR AFTERNOON CONVECTION...SEE ABOVE FOR WHY IT IS LOOKING LIKE IT WILL BE TOUGH TO GET MUCH GOING TODAY...ESPECIALLY ACROSS MN. COUPLE OF THE HOPWRF MEMBERS STILL SHOWING SOME SCT CONVECTION DEVELOPING IN WRN WI THIS AFTERNOON...SO LEFT A PROB30 TSRA MENTION IN FOR EAU...BUT THAT IS IT. TONIGHT...FOG MAY BECOME A BIG ISSUE AS SKIES CLEAR OUT AND WINDS GO LIGHT AND VRB. WI LOOKS TO HAVE THE GREATEST POTENTIAL FOR DENSE FOG...AS THEY WILL BE THE COOLEST TODAY THANKS TO CLOUDS CLEARING OUT THERE LAST. NMM/ARW BOTH SHOW DENSE FOG DEVELOPING IN WI TONIGHT...SO STARTED TO SHOW SIGNS OF THAT AT THE END OF THE TAFS FOR RNH/EAU. WILL PROBABLY HAVE TO KEEP AN EYE ON THE FG FOR STC AS WELL. KMSP...WILL PROBABLY SEE A HIGH DEGREE OF VARIABILITY IN CIGS FOR THE FIRST COUPLE OF HOURS OF THE TAF...BUT BY 14Z...EXPECT A FAIRLY PERSISTENT DECK OF STRATUS DEVELOP IN THE 015 TO 020 RANGE. TILL THEN WILL LIKELY MAKE SOME PRETTY RAPID AND FREQUENT JUMPS BETWEEN IFR/VFR CIGS. WITH DEWPS BACK IN THE 60S AND HIGHS AROUND 80...CAN NOT COMPLETELY RULE OUT A STRAY SHRA/TSRA THIS AFTERNOON...BUT IT DOES NOT LOOK WORTHY OF MENTIONING IN THE TAF. TONIGHT...MAY HAVE SOME FOG TO DEAL WITH IN THE RIVER VALLEY. /OUTLOOK FOR KMSP/ TUE...TSRA LIKELY AFTERNOON/EVENING. VFR OUTSIDE OF TSRA. WINDS WSW 5-10KTS...BCMG NW OVERNIGHT. WED...VFR. WINDS NW 10 KTS. THU...VFR. CHC TSRA OVERNIGHT. WINDS SW 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM... AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
328 AM CDT MON AUG 5 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT MON AUG 5 2013 A 30 KT LLJ NOSING UP INTO SW MN EARLY THIS MORNING HAS FORCED A FAIRLY BROAD SHIELD OF SHOWERS WITH EMBEDDED THUNDERSTORMS THAT HAS BEEN STEADILY MAKING ITS WAY ACROSS MN THIS MORNING. ELEVATED INSTABILITY HAS NOT MADE MUCH PROGRESS NE THOUGH...WHICH IS WHY ANY DEEPER CONVECTION HAS ESSENTIALLY BEEN CRAWLING AROUND THE MPX CWA BORDER WITH FSD. MOST OF THE HOPWRF MEMBERS ALONG WITH THE LOCAL MPX-WRF HAVE ALL DONE A DECENT JOB IN CAPTURING WHAT HAS HAPPENED SO FAR OVERNIGHT IN TERMS PRECIP PLACEMENT...THEY HAVE ALL JUST BEEN ABOUT 2 HOURS BEHIND SCHEDULE. AS A RESULT...WAS FAIRLY AGGRESSIVE WITH MOVING LIKELY OR BETTER POPS OUT OF THE AREA THIS MORNING. BASED ON CURRENT MOVEMENT...BACK EDGE OF THE SHOWERS OVER CENTRAL MN WILL BE CLEARING THE EAU AREA AROUND 11Z...SO CERTAINLY DOES NOT MAKE MUCH SENSE TO HAVE MUCH IN THE WAY OF POPS BEYOND 15Z. THE ONLY POTENTIAL PROBLEM FOR THIS FASTER PROGRESSION OF LOWER POPS THROUGH THE AREA IS THE FACT THAT THERE IS A SFC TROUGH/COLD FRONT FEATURE CURRENTLY MOVING THROUGH THE ERN DAKOTAS THAT THE HRRR IS TRYING TO DEVELOP ANOTHER LINE OF CONVECTION ALONG LATER THIS MORNING. HAVE SEEN A FEW SPECKLES ON THE RADAR TO THE WEST OF THE MAIN PRECIP SHIELD OVER WRN MN...BUT TO THIS POINT WE HAVE NOT SEEN ANYTHING TO SUGGEST STORMS ON THE ORDER OF THE WHAT THE 5Z AND 6Z VERSIONS OF THE HRRR HAVE BEEN SHOWING DEVELOPING NEAR THE MN/SD. WITH MAIN PUSH OF MOISTURE TRANSPORT FOLLOWING THE PRECIP SHIELD EAST AND WITH AT LEAST SOME DEGREE OF OVERTURNING OCCURRING WITH THE FIRST ROUND OF RAIN...HAVE FAVORED THE FASTER DEPARTURE OF PRECIP...THOUGH THIS MAY NEED TO BE CHANGED BEFORE RUNNING OUT THE DOOR AT 6 AM. FOR THIS AFTERNOON...BIG CHANGE TO THE FORECAST WAS TO BOOST HIGHS A FEW DEGREES...MAINLY OVER MN. BASED ON THE HOPWRF...ALONG WITH THE RAP...EXPECT SKIES TO OPEN UP PRETTY GOOD BY THIS AFTERNOON BEHIND THIS MORNINGS ACTIVITY. WITH H85 TEMPS IN THE NEIGHBORHOOD OF 16C...THIS WOULD FAVOR MIXING DOWN HIGHS INTO THE LOW TO MID 80S ACROSS MN. HELD HIGHS IN THE 70S ACROSS WI WHERE CLOUD COVER WILL BE MORE PERSISTENT. OF COURSE IF THE CLOUDS DO NOT CLEAR OUT AS PLANNED...THEN IT WILL BE A SECOND DAY IN A ROW WHERE CLOUDS RESULT IN A FORECAST THAT IS A BIT OVERDONE ON THE HIGHS.... FOR THIS AFTERNOON...THAT AFOREMENTIONED DAKOTAS THROUGH WILL MEANDER OVER TO NEAR THE MN/WI BORDER. THE GFS DEVELOPS UP TO 1000 J/KG OF MLCAPE OUT AHEAD OF THIS BOUNDARY...WHICH MAY BE ENOUGH TO GENERATE SOME ISO/SCT STORMS. HOWEVER...BEHIND THIS MORNINGS WAVE...ALL MODELS SHOW SOME PRETTY EXTENSIVE DRYING AND SUBSIDENCE IN THE MID-LEVELS. NAM/RAP SOUNDINGS SHOW A DECENT SUBSIDENCE INVERSION DEVELOPING AROUND H7 AS WELL. ALL OF THIS POINTS TO WHAT SHOULD BE A DRY DAY...THOUGH WITH INSTABILITY FORECAST TO BE IN PLACE...CAN NOT COMPLETELY RULE OUT SOME DIURNALLY DRIVEN THUNDERSTORM ACTIVITY DEVELOPING...SO HAVE LEFT SOME 20-30 POPS IN PLACE THIS AFTERNOON FOR ERN MN INTO WRN WI. FOR TONIGHT...THE MPX AREA LOOKS TO BE CAUGHT BETWEEN AREAS OF FORCING FOR PRECIP...WITH CURRENT PRECIPITATION HEADING FOR MICHIGAN AND THE FRONT FOR TUESDAY AFTERNOON REMAINING FAR ENOUGH NW TO KEEP THE AREA DRY. AT THE MOMENT...EXPECT MAINLY CLEAR SKIES TONIGHT...WITH LIGHT AND VARIABLE WINDS. WITH DEWPS UP IN THE UPPER 50S TO MID 60S...THIS COULD LEAD TO SOME POCKETS OF FOG DEVELOPING OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 330 AM CDT MON AUG 5 2013 THE MAIN FORECAST CONCERN DURING THE TUESDAY THROUGH SUNDAY PERIOD WILL BE THE CHANCES FOR SHRA/TSRA TUESDAY AFTERNOON INTO TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH THE REGION. THE REMAINS SOME VARIABILITY IN THE TIMING AND ORIENTATION OF THE FRONT AMONGST THE GFS... NAM... ECMWF... AND SREF... WITH THE NAM BEING FASTEST AND ECMWF BEING SLOWEST. A SHORTWAVE ROTATING EAST FROM THE NORTHERN ROCKIES WILL HELP DRIVE THE FRONT ACROSS THE AREA WHILE THE MAIN UPPER TROUGH DROPS SOUTH FROM CANADA. LARGE SCALE FORCING IN TERMS OF UPPER DIVERGENCE AND DPVA LOOK SUFFICIENT FOR FAIRLY WIDESPREAD PCPN TO OCCUR ALONG/AHEAD OF THE FRONT... WITH THALER QG DIAGNOSTICS DEPICTING AN ELONGATED AREA OF GOOD 700MB OMEGA FROM WESTERN LAKE SUPERIOR INTO NORTHWEST IOWA BY 00Z WEDNESDAY. THIS SHOULD BE MORE THAN SUFFICIENT TO GET SHRA/TSRA GOING DURING THE AFTERNOON HOURS AS THE FRONT MOVES THROUGH THE AREA. THE QUESTION THEN BECOMES WHETHER OR NOT ANY SEVERE WEATHER CAN BE EXPECTED. THE NEW DAY 2 OUTLOOK FROM SPC DOES INCLUDE A SLIGHT RISK ACROSS MOST OF THE AREA... ESSENTIALLY NEAR AND SOUTH OF I-94. IT LOOKS LIKE WE/LL HAVE ANYWHERE FROM 1000-2000 J/KG OF MLCAPE WITH WHICH TO WORK... ALONG WITH DEEP LAYER SHEAR AOA 40 KT... SO SOME ORGANIZED CONVECTION IS CERTAINLY POSSIBLE. DEEP LAYER SHEAR WILL BE SUFFICIENT FOR SUPERCELLS... BUT WOULDN/T EXPECT THE MODE TO REMAIN DISCRETE FOR VERY LONG GIVEN THE EXPECTATION FOR SOMEWHAT WIDESPREAD DEVELOPMENT. SO... CURRENT EXPECTATIONS WOULD BE FOR INITIAL SUPERCELLS TO QUICKLY TRANSITION INTO CLUSTERS AND A LINEAR SYSTEM WITH TIME. LOW LEVEL SHEAR DOESN/T LOOK TO BE TOO SIGNIFICANT... LIKELY AOB 15-20KT... WHICH SHOULD KEEP TORNADOES FROM BEING MUCH OF A THREAT... LEAVING LARGE HAIL AND WIND AS THE MAIN POTENTIAL ISSUES. THE FRONT SHOULD PUSH THROUGH THE REMAINDER OF THE FORECAST AREA TUESDAY NIGHT... WITH DRY WEATHER AND COOLER TEMPERATURES ON WEDNESDAY AS CANADIAN HIGH PRESSURE BUILDS INTO THE AREA. THE NEXT CHANCE FOR PCPN LOOKS TO HOLD OFF UNTIL THURSDAY AFTERNOON AND THURSDAY NIGHT... WHEN THE MAIN UPPER LOW OVER CENTRAL CANADA DROPS SOUTH TOWARD THE INTERNATIONAL BORDER AND ANOTHER COLD FRONT PUSHES ACROSS THE REGION. MOISTURE RETURN WILL BE LIMITED AHEAD OF THE FRONT... BUT WILL BE SUFFICIENT GIVEN DECENT FORCING FOR SOME SHRA/TSRA. KEPT THINGS MAINLY DRY FROM FRIDAY THROUGH SUNDAY WITH THE EXPECTATION THAT AN EXPANSIVE HIGH WILL BUILD IN FROM CANADA. HOWEVER... IT SHOULD BE NOTED THAT THE 00Z ECMWF IS MORE PROGRESSIVE THAN THE GFS WITH THE UPPER PATTERN AND MANAGES TO FLATTEN THE FLOW OVER THE NORTH CENTRAL CONUS AND BRINGS A SURFACE LOW ACROSS MINNESOTA ON SUNDAY WITH DECENT FRONTOGENESIS AND AN ACCOMPANYING SLUG OF PCPN. STUCK CLOSER TO THE PREVIOUS FORECAST AND GFS AT THIS POINT... AND JUST INCLUDED SOME CHANCE POPS OVER THE SOUTHWEST PORTION OF THE CWFA ON SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 110 AM CDT MON AUG 5 2013 THUNDERSTORM COMPLEX OVER MN NOW IS MAIN CONCERN FOR THESE TAFS. BIG THING TO NOTE ABOUT THIS COMPLEX IS BASED ON CURRENT TRENDS...NOTHING IS FAST ENOUGH WITH HANDLING THIS COMPLEX. BASED ON HOW THINGS ARE LINING UP ON RADAR...PREFER A 00Z HOPWRF IDEA WITH PRIMARY AXIS OF PRECIPITATION ALIGNING FAIRLY CLOSELY TO THE MN RIVER VALLEY FROM WC MN INTO SE MN/NE IA. FOR TIMING...STUCK CLOSE TO THE IDEA OF THE HOPWRF MEMBERS...JUST SPED THEM UP A COUPLE OF HOURS. THAT GETS THUNDER OUT OF AXN WITHIN THE HOUR...THROUGH MSP BY AROUND 10Z AND OUT OF THE EAU AREA SHORTLY AFTER 12Z. AS THESE SHOWERS MOVE THROUGH...WILL HAVE TO WATCH FOR THE DEVELOPMENT OF MVFR OR LOWER CIGS THAT COULD PLAGUE SITES MUCH OF THE MORNING. FOR THE AFTERNOON...EXPECT SKIES TO SCT OUT. BASED ANY AFTERNOON THUNDER POTENTIAL ON THE GFS...WHICH CONFINES INSTABILITY TO WRN WI THIS AFTERNOON. WILL BE A BOUNDARY WORKING INTO THERE AS WELL...WHICH SUPPORTS THE IDEA OF SOME SCT TSRA DEVELOPING IN THE EAST THIS AFTERNOON. FOR TONIGHT...SKIES SHOULD GO MOSTLY CLEAR WITH WINDS GOING LGT AND VRB. KMSP...BASED SHRA/TSRA TIMING MORE ON CURRENT TRENDS THEN ANY BIT OF GUIDANCE...AS ALL GUIDANCE IS BEHIND THE CURVE IN TERMS OF TIMING OF CURRENT ACTIVITY. HEAVIEST PRECIP STILL LOOKS TO BE GOING SOUTH OF THE FIELD...THOUGH STILL LOOKS GOOD FOR AN UP TO 2 HOUR PERIOD OF SHRA/TSRA BETWEEN MAINLY 8Z AND 10Z. DO EXPECT CIGS TO DEVELOP BEHIND THE RAIN...BUT STILL LOTS OF QUESTIONS AS TO HOW LOW THEY WILL BE. CURRENTLY IN SW MN/SE SD CIGS ARE MAINLY CHECKING IN AT 3K TO 4K FT...SO CURRENT TAF MAY BE OVERDONE. CONFIDENCE IS HIGH IN THE REST OF THE TAF BEING DRY...WITH ANY SCT ACTIVITY THIS AFTERNOON ENDING UP EAST OF THE FIELD. /OUTLOOK FOR KMSP/ TUE...TSRA LIKELY AFTERNOON/EVENING. VFR OUTSIDE OF TSRA. WINDS WSW 5-10KTS...BCMG NW OVERNIGHT. WED...VFR. WINDS NW 10 KTS. THU...VFR. CHC TSRA OVERNIGHT. WINDS SW 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM... AVIATION...MPG
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
946 PM CDT Tue Aug 6 2013 .UPDATE... Issued at 945 PM CDT TUE AUG 6 2013 Have made some minor changes to PoPs to account for trends with convection across northern Missouri and convection over southern Kansas possibly moving in later tonight. Also, confidence is increasing that we`ll see thunderstorms develop between 10pm and midnight in our far southern zones. ACCAS was evident on visible imagery before sunset and on IR imagery before the cirrus shield from the Kansas storms obscured things. Still, an arc of ACCAS can be inferred from southern Missouri to around Harrisonville. The HRRR, our local WRF and the RAP all generate storms in this arc within the next few hours. Across our north, thunderstorms have developed ahead of the main front, possible on or near a residual outflow boundary. Instability will remain moderate to strong overnight and shear may be enough for some storm organization. But updrafts have had a hard time persisting for very long to utilize the shear. Overall, the initial updrafts are more likely to produce marginally severe hail tonight. Otherwise the greatest threat should be from heavy rain and localized, especially if storms in our south develop and track over areas that saw rain late last night/early this morning. Localized strong to damaging winds may also continue into the night with any of the strongest storms. && .SHORT TERM...(This Evening through Wednesday Night) Issued at 331 PM CDT TUE AUG 6 2013 Tonight: Another potentially active period is anticipated late this evening into the overnight hours for much of the forecast area. Several boundaries are noted across the region as of early this afternoon, all that may potentially contribute as a focus for convective development during the next 12 hours. An outflow boundary from earlier convection over Nebraska and Iowa, identified by surface observations and transient convective towers, has pushed southward into northern Missouri, approximately 70 miles north of the Interstate 70 corridor. Second, a poorly defined thermal boundary that has been a primary driving force for several days remains across southeast Kansas into southern Missouri. Lastly, a cold front over the Nebraska Panhandle into southeast South Dakota continues a steady southward push. These boundaries will be the main focus for additional showers and thunderstorm development across the forecast area this evening and overnight. Upslope flow over the High Plains will once again help promote scattered thunderstorms over western Kansas this afternoon. This activity will likely evolve into a complex of thunderstorms and move eastward during the evening. While the initial activity may gradually weaken, a strengthening 30kt low-level jet will induce additional convection along and north of the aforementioned boundaries across the CWA. This overall philosophy is supported by recent convective-resolving and operational models, and is similar to last nights evolution. Additional thunderstorms may develop along the cold front over Nebraska and Iowa, with a complex of thunderstorms moving towards northern Missouri. Models have struggled with consistently developing activity in this region, and the lack of a cumulus field along the boundary remains. Nevertheless, sufficient forcing should allow for thunderstorms to develop in this region, but uncertainty remains to how far south the activity will persist. Overall, uncertainty exists with current forecast with regards to timing and coverage for tonight, but enough evidence supports scattered to occasionally widespread convection over portions of the CWA overnight. With high precipitable water values and moderate instability, the most robust convection will be capable of heavy rainfall and localized damaging wind gusts. While widespread flooding concerns are not expected at this stage, localized flooding in some creeks or streams cannot be ruled out. Wednesday/Wednesday night: The majority of moderate/heavy rainfall should be in the process of exiting the CWA around sunrise Wed. The cold front will push through the forecast area no later than mid-morning Wednesday, with northerly winds occurring behind the boundary. Some drier air will advect into the northern portion of the CWA by Wed evening, while a humid airmass should remain elsewhere. Scattered showers or weak thunderstorms will be possible north of the frontal boundary during the daylight hours, mainly south of Interstate 70. A much more substantial chance for rainfall is expected Wednesday night into Thursday morning, mainly for areas along and south of Interstate 70. Here, embedded waves within the upper low and increasing isentropic ascent should lead to widespread convective development. Areas of heavy rainfall will be possible, and depending on tonights convective episode, concern may increase for flooding late Wed night into Thursday as grounds become saturated. More specifics will be realized in subsequent forecasts as details on frontal position, wave timing, and previous convective evolution becomes known. .LONG TERM...(Thursday through Tuesday) Issued at 331 PM CDT TUE AUG 6 2013 Long term forecast will remain focused on surface boundary across the region and numerous short wave troughs moving through the flow providing a chance for precipitation through much of the period. Hudson Bay low will begin to quickly translate eastward across the northern Great Lakes region as a shortwave trough rounds the southern edge of a newly developing region of low pressure in this same area. General northwest flow pattern across the central US will quickly begin to break down as a region of low pressure moves out of Baja California and into the Four Corners region. The trough will continue to move eastward across the Rockies and out onto the Plains by the end of the week. As this system nears the region...it will interact with a quasi-stationary surface boundary that will be positioned across the Central Plains. Depending on where this boundary eventually positions itself will decide where main convective activity will likely develop. Current long-range models indicate that there is the potential for storms to redevelop over the same general region through much of the period. With precipitable water values progged to be 1.5 to 2 inches across many areas, expect heavy rain to develop leading to potential flooding issues in these locations. By early next week, models begin to diverge with the EC rebuilding a ridge over the Rockies and keeping more of a pronounced northwest flow component while the GFS develops a broader ridge with more of a zonal component to the flow over the CWA. Both models bring numerous shortwave troughs across the region, but timing of these features remain uncertain and will effect precipitation chances. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) Issued at 627 PM CDT TUE AUG 6 2013 VFR conditions are likely to prevail through the entire forecast. The exception may be during a possible thunderstorm complex late tonight and in the wake of any complex through tomorrow morning. But confidence in actually getting any storms into the terminals is rather low at this time so have maintained the VCTS group but delayed it an hour or two. If thunderstorms do impact the terminals the most likely timing looks to be after 06Z through sunrise, impacting morning flight operations. Thunderstorm chances look low through the remainder of the valid period. Winds will be light throughout the period but will switch from the south/southwest currently and this evening to a more northerly direction by tomorrow morning as a front moves through. Once winds switch to the north/northeast they should remain from that direction for the remainder of the forecast. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...CDB SHORT TERM...Blair LONG TERM...PMM AVIATION...CDB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1256 PM CDT MON AUG 5 2013 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 335 AM CDT MON AUG 5 2013 THE LARGE SCALE FLOW REGIME HAS CHANGED LITTLE OVER THE LAST 24 HOURS WITH A VORTEX OVER HUDSON BAY AND UPPER HIGH CENTERED IN WEST TX AND NW FLOW ALOFT THROUGH THE NATIONS MIDSECTION. WEAK DISTURBANCES ALOFT CONTINUE TO TRACK FROM THE CENTRAL ROCKIES ESEWD THRU KS WITHIN THE FLOW ALOFT. CLUSTERS OF THUNDERSTORMS ACROSS SE KS AND SW MO EARLY THIS MORNING ARE OCCURING TO THE NORTH OF A QUASI- STATIONARY BOUNDARY DRAPPED FROM THE OK PANHANDLE INTO THE LOWER MS VALLEY AND IN ADVANCE OF ONE OF THESE WEAK DISTURBANCES...AND ARE STRONGLY DRIVEN BY A BROAD 30+ KT SWLY LLJ. MODEL CONSENSUS AND RECENT RUNS OF THE HRRR SUGGEST A FAMILIAR THEME TO RECENT MORNINGS...THE ACTIVITY WILL TRACK ESEWD THIS MORNING IN ADVANCE OF THE MIGRATING DISTURBANCE AND AS THE LLJ VEERS TO MORE WESTERLY. THIS SHOULD BRING THE GREATEST IMPACT OF THE WEAKENING SHOWERS AND THUNDERSTORMS TO THE EASTERN OZARKS THIS MORNING...WITH ANY RESIDUAL SHOWERS EXITING BY EARLY AFTERNOON. FORCING FOR ANY PRECIPITATION IS RATHER WEAK AND NON-FOCUSED ELSEWHERE AND WORTHY OF A MERE SLIGHT CHANCE. I THINK THERE WILL BE A SLIGHT NORTHWARD JOG IN THE MCS TRACK TONIGHT INTO TUESDAY AS THE BOUNDARY TO THE SOUTH LIFTS SLIGHTLY AND DISTURBANCES ALOFT TRACK A TAD FURTHER NORTH THAN THE LAST SEVERAL DAYS. PRESENT INDICATIONS ARE THAT THE ONE OR MORE MCSS WILL DEVELOP FROM SOUTH CENTRAL KS INTO SOUTH CENTRAL MO AS THE SWLY LLJ RAMPS UP THIS EVENING AND THEN STRENGTHENS AND VEERS OVERNIGHT. THIS ACTIVITY WILL BE ONGOING WITHIN THIS CORRIDOR AT DAYBREAK TUESDAY AND SHIFTING TO THE ESE DURING THE DAY IN ADVANCE OF THE MIGRATING DISTURBANCE ALOFT AND AS THE LLJ CONTINUES TO VEER. THE HIGHEST POPS WILL BE CONCENTRATED ALONG AN AXIS JEFFERSON CITY TO FARMINGTON. GLASS .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 AM CDT MON AUG 5 2013 CONSENSUS OF THE ECMWF...SREF...AND NAM IS WE SHOULD SEE A SYNOPTIC SCALE COLD FRONT PUSH INTO NRN SECTIONS OF THE AREA LATE TUESDAY NIGHT AND PROGRESS SEWD DURING THE DAY ON WEDNESDAY. A BROAD SWLY LLJ OF 30+ KTS REMAINS FOCUSED AHEAD OF THE FRONT TUESDAY NIGHT AND SHOULD SUPPORT LIKELY PROBABILITIES OF SHOWERS AND THUNDERSTORMS WITH THAT THREAT SHIFTING SEWD AHEAD OF THE FRONT ON WEDNESDAY. THE UPPER FLOW REGIME WILL CHANGE SLIGHTLY WEDNESDAY THROUGH FRIDAY WITH A MORE ZONAL COMPONENT WHILE THE FRONT BECOMES QUASI-STATIONARY FROM THE TN VALLEY ACROSS ARKANSAS INTO NORTHERN OK. THIS MORE ZONAL COMPONENT IN THE FLOW ALOFT WILL BRING THE DISTURBANCE TRACK WEST TO EAST MORE THROUGH THE MID MS VALLEY AND MODULATE THE S/SWLY LLJ...TO BRING A CONTINUED THREAT OF SHOWERS AND THUNDERSTORMS TO THE SOUTHERN 2/3RDS OF THE CWA AT LEAST INTO FRIDAY. GLASS && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1241 PM CDT MON AUG 5 2013 RIDGE OF SFC HIGH PRESSURE CONTINUE TO SLIDE OFF TO THE EAST WITH WINDS NOW OUT OF THE SOUTH NEAR 10 KTS. RAIN ASSOCIATED WITH OVERNIGHT MCS HAS LARGELY STAYED SOUTH OF TAF SITES. HOWEVER...SOME MVFR CEILINGS ARE POSSIBLE THROUGH MID AFTERNOON TO THE NORTH OF THIS FEATURE. CEILINGS WILL ALSO BE THE PRIMARY CONCERN TONIGHT. FRONT OVER THE MID SOUTH WILL RETREAT NORTHWARD TONIGHT AS A WARM FRONT WITH WINDS BACKING MORE TO THE SOUTHEAST AROUND 5 KNOTS. LOW CEILINGS ARE LIKELY WITH FOG POSSIBLE AHEAD OF THE FRONT AND AM FORECASTING MVFR CEILINGS...THOUGH MODELS INDICATE THEY COULD DIP DOWN INTO IFR. WARM FRONT WILL PASS THROUGH THE AREA BY AROUND NOON WITH AREAS TO THE SOUTH OF THE BOUNDARY HAVING WINDS VEER TO THE SOUTH SOUTHWEST. SPECIFICS FOR KSTL... RIDGE OF SFC HIGH PRESSURE CONTINUE TO SLIDE OFF TO THE EAST WITH WINDS NOW OUT OF THE SOUTH NEAR 10 KTS. RAIN ASSOCIATED WITH OVERNIGHT MCS HAS LARGELY STAYED SOUTH OF LAMBERT FIELD. HOWEVER...SOME MVFR CEILINGS ARE POSSIBLE THROUGH MID AFTERNOON TO THE NORTH OF THIS FEATURE. LEFT OUT OF TAF FOR NOW AS 975 TO 900 HPA MEAN FLOW HAS VEERED TO THE WEST NORTHWEST AND SHOULD KEEP THESE AFOREMENTIONED CEILINGS JUST TO THE SOUTH OF THE TERMINAL. HOWEVER...WILL MONITOR AND AMEND AS NECESSARY THIS AFTERNOON. CEILINGS WILL ALSO BE THE PRIMARY CONCERN TONIGHT. FRONT OVER THE MID SOUTH WILL RETREAT NORTHWARD TONIGHT AS A WARM FRONT WITH WINDS BACKING MORE TO THE SOUTHEAST AROUND 5 KNOTS. LOW CEILINGS ARE LIKELY WITH FOG POSSIBLE AHEAD OF THE FRONT AND AM FORECASTING MVFR CEILINGS...THOUGH MODELS INDICATE THEY COULD DIP DOWN INTO IFR. WARM FRONT WILL PASS THROUGH THE AREA BY AROUND NOON WITH AREAS TO THE SOUTH OF THE BOUNDARY HAVING WINDS VEER TO THE SOUTH SOUTHWEST. THE ATMOSPHERE WILL ALSO BECOME INCREASINGLY UNSTABLE SO INTRODUCED A VCSH GROUP BEGINNING AT 1900 UTC. GOSSELIN && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
709 AM CDT MON AUG 5 2013 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 335 AM CDT MON AUG 5 2013 THE LARGE SCALE FLOW REGIME HAS CHANGED LITTLE OVER THE LAST 24 HOURS WITH A VORTEX OVER HUDSON BAY AND UPPER HIGH CENTERED IN WEST TX AND NW FLOW ALOFT THROUGH THE NATIONS MIDSECTION. WEAK DISTURBANCES ALOFT CONTINUE TO TRACK FROM THE CENTRAL ROCKIES ESEWD THRU KS WITHIN THE FLOW ALOFT. CLUSTERS OF THUNDERSTORMS ACROSS SE KS AND SW MO EARLY THIS MORNING ARE OCCURING TO THE NORTH OF A QUASI- STATIONARY BOUNDARY DRAPPED FROM THE OK PANHANDLE INTO THE LOWER MS VALLEY AND IN ADVANCE OF ONE OF THESE WEAK DISTURBANCES...AND ARE STRONGLY DRIVEN BY A BROAD 30+ KT SWLY LLJ. MODEL CONSENSUS AND RECENT RUNS OF THE HRRR SUGGEST A FAMILIAR THEME TO RECENT MORNINGS...THE ACTIVITY WILL TRACK ESEWD THIS MORNING IN ADVANCE OF THE MIGRATING DISTURBANCE AND AS THE LLJ VEERS TO MORE WESTERLY. THIS SHOULD BRING THE GREATEST IMPACT OF THE WEAKENING SHOWERS AND THUNDERSTORMS TO THE EASTERN OZARKS THIS MORNING...WITH ANY RESIDUAL SHOWERS EXITING BY EARLY AFTERNOON. FORCING FOR ANY PRECIPITATION IS RATHER WEAK AND NON-FOCUSED ELSEWHERE AND WORTHY OF A MERE SLIGHT CHANCE. I THINK THERE WILL BE A SLIGHT NORTHWARD JOG IN THE MCS TRACK TONIGHT INTO TUESDAY AS THE BOUNDARY TO THE SOUTH LIFTS SLIGHTLY AND DISTURBANCES ALOFT TRACK A TAD FURTHER NORTH THAN THE LAST SEVERAL DAYS. PRESENT INDICATIONS ARE THAT THE ONE OR MORE MCSS WILL DEVELOP FROM SOUTH CENTRAL KS INTO SOUTH CENTRAL MO AS THE SWLY LLJ RAMPS UP THIS EVENING AND THEN STRENGTHENS AND VEERS OVERNIGHT. THIS ACTIVITY WILL BE ONGOING WITHIN THIS CORRIDOR AT DAYBREAK TUESDAY AND SHIFTING TO THE ESE DURING THE DAY IN ADVANCE OF THE MIGRATING DISTURBANCE ALOFT AND AS THE LLJ CONTINUES TO VEER. THE HIGHEST POPS WILL BE CONCENTRATED ALONG AN AXIS JEFFERSON CITY TO FARMINGTON. GLASS .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 AM CDT MON AUG 5 2013 CONSENSUS OF THE ECMWF...SREF...AND NAM IS WE SHOULD SEE A SYNOPTIC SCALE COLD FRONT PUSH INTO NRN SECTIONS OF THE AREA LATE TUESDAY NIGHT AND PROGRESS SEWD DURING THE DAY ON WEDNESDAY. A BROAD SWLY LLJ OF 30+ KTS REMAINS FOCUSED AHEAD OF THE FRONT TUESDAY NIGHT AND SHOULD SUPPORT LIKELY PROBABILITIES OF SHOWERS AND THUNDERSTORMS WITH THAT THREAT SHIFTING SEWD AHEAD OF THE FRONT ON WEDNESDAY. THE UPPER FLOW REGIME WILL CHANGE SLIGHTLY WEDNESDAY THROUGH FRIDAY WITH A MORE ZONAL COMPONENT WHILE THE FRONT BECOMES QUASI-STATIONARY FROM THE TN VALLEY ACROSS ARKANSAS INTO NORTHERN OK. THIS MORE ZONAL COMPONENT IN THE FLOW ALOFT WILL BRING THE DISTURBANCE TRACK WEST TO EAST MORE THROUGH THE MID MS VALLEY AND MODULATE THE S/SWLY LLJ...TO BRING A CONTINUED THREAT OF SHOWERS AND THUNDERSTORMS TO THE SOUTHERN 2/3RDS OF THE CWA AT LEAST INTO FRIDAY. GLASS && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 707 AM CDT MON AUG 5 2013 MCS COMPLEX OVER SOUTHWESTERN MO TO CONTINUE TRACKING TO THE EAST SOUTHEAST THIS MORNING...SLIDING JUST SOUTH OF TAF SITES. COULD SEE SOME ISOLATED/SCATTERED ACTIVITY AT KCOU...BUT CONFIDENCE IS LOW...SO JUST KEPT VCSH MENTION THERE. OTHERWISE...MAIN ISSUE TO DEAL WITH IS VARIABLE CLOUD HEIGHTS. IFR/MVFR CIGS HAVE DEVELOPED NORTH OF COMPLEX OVER CENTRAL MO...BUT NOT SURE HOW LONG THEY WILL PERSIST. FOR NOW HAVE MVFR/IFR CIGS SCATTERING OUT AT KCOU/KUIN BY 14Z. REST OF TAF SITES TO SEE LOW END VFR CIGS THROUGH MIDDAY...BEFORE SCATTERING OUT. AS FOR WINDS...TO PERSIST FROM THE SOUTH AND INCREASE TO AROUND 10KTS...THEN DIMINISH TOWARDS SUNSET. ANOTHER ROUND OF STORMS IS POSSIBLE TONIGHT THAT WOULD AFFECT CENTRAL MO...SO ADDED VCSH MENTION TO KCOU AFTER 10Z TUESDAY. SPECIFICS FOR KSTL...MCS COMPLEX OVER SOUTHWESTERN MO TO CONTINUE TRACKING TO THE EAST SOUTHEAST THIS MORNING...SLIDING JUST SOUTH OF TAF SITES. OTHERWISE...MAIN ISSUE TO DEAL WITH IS VARIABLE CLOUD HEIGHTS. LOW END VFR CIGS EXPECTED TO MOVE IN AND PERSIST THROUGH MIDDAY...BEFORE SCATTERING OUT. AS FOR WINDS...TO PERSIST FROM THE SOUTH AND INCREASE TO AROUND 10KTS...THEN DIMINISH TOWARDS SUNSET. ANOTHER ROUND OF STORMS IS POSSIBLE TONIGHT THAT WOULD NOT MOVE INTO METRO AREA TIL AFTER 14Z TUESDAY...SO ADDED VCSH MENTION TO KSTL DURING THIS PERIOD. BYRD && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
341 AM CDT MON AUG 5 2013 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 335 AM CDT MON AUG 5 2013 THE LARGE SCALE FLOW REGIME HAS CHANGED LITTLE OVER THE LAST 24 HOURS WITH A VORTEX OVER HUDSON BAY AND UPPER HIGH CENTERED IN WEST TX AND NW FLOW ALOFT THROUGH THE NATIONS MIDSECTION. WEAK DISTURBANCES ALOFT CONTINUE TO TRACK FROM THE CENTRAL ROCKIES ESEWD THRU KS WITHIN THE FLOW ALOFT. CLUSTERS OF THUNDERSTORMS ACROSS SE KS AND SW MO EARLY THIS MORNING ARE OCCURING TO THE NORTH OF A QUASI- STATIONARY BOUNDARY DRAPPED FROM THE OK PANHANDLE INTO THE LOWER MS VALLEY AND IN ADVANCE OF ONE OF THESE WEAK DISTURBANCES...AND ARE STRONGLY DRIVEN BY A BROAD 30+ KT SWLY LLJ. MODEL CONSENSUS AND RECENT RUNS OF THE HRRR SUGGEST A FAMILIAR THEME TO RECENT MORNINGS...THE ACTIVITY WILL TRACK ESEWD THIS MORNING IN ADVANCE OF THE MIGRATING DISTURBANCE AND AS THE LLJ VEERS TO MORE WESTERLY. THIS SHOULD BRING THE GREATEST IMPACT OF THE WEAKENING SHOWERS AND THUNDERSTORMS TO THE EASTERN OZARKS THIS MORNING...WITH ANY RESIDUAL SHOWERS EXITING BY EARLY AFTERNOON. FORCING FOR ANY PRECIPITATION IS RATHER WEAK AND NON-FOCUSED ELSEWHERE AND WORTHY OF A MERE SLIGHT CHANCE. I THINK THERE WILL BE A SLIGHT NORTHWARD JOG IN THE MCS TRACK TONIGHT INTO TUESDAY AS THE BOUNDARY TO THE SOUTH LIFTS SLIGHTLY AND DISTURBANCES ALOFT TRACK A TAD FURTHER NORTH THAN THE LAST SEVERAL DAYS. PRESENT INDICATIONS ARE THAT THE ONE OR MORE MCSS WILL DEVELOP FROM SOUTH CENTRAL KS INTO SOUTH CENTRAL MO AS THE SWLY LLJ RAMPS UP THIS EVENING AND THEN STRENGTHENS AND VEERS OVERNIGHT. THIS ACTIVITY WILL BE ONGOING WITHIN THIS CORRIDOR AT DAYBREAK TUESDAY AND SHIFTING TO THE ESE DURING THE DAY IN ADVANCE OF THE MIGRATING DISTURBANCE ALOFT AND AS THE LLJ CONTINUES TO VEER. THE HIGHEST POPS WILL BE CONCENTRATED ALONG AN AXIS JEFFERSON CITY TO FARMINGTON. GLASS .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 AM CDT MON AUG 5 2013 CONSENSUS OF THE ECMWF...SREF...AND NAM IS WE SHOULD SEE A SYNOPTIC SCALE COLD FRONT PUSH INTO NRN SECTIONS OF THE AREA LATE TUESDAY NIGHT AND PROGRESS SEWD DURING THE DAY ON WEDNESDAY. A BROAD SWLY LLJ OF 30+ KTS REMAINS FOCUSED AHEAD OF THE FRONT TUESDAY NIGHT AND SHOULD SUPPORT LIKELY PROBABILITIES OF SHOWERS AND THUNDERSTORMS WITH THAT THREAT SHIFTING SEWD AHEAD OF THE FRONT ON WEDNESDAY. THE UPPER FLOW REGIME WILL CHANGE SLIGHTLY WEDNESDAY THROUGH FRIDAY WITH A MORE ZONAL COMPONENT WHILE THE FRONT BECOMES QUASI-STATIONARY FROM THE TN VALLEY ACROSS ARKANSAS INTO NORTHERN OK. THIS MORE ZONAL COMPONENT IN THE FLOW ALOFT WILL BRING THE DISTURBANCE TRACK WEST TO EAST MORE THROUGH THE MID MS VALLEY AND MODULATE THE S/SWLY LLJ...TO BRING A CONTINUED THREAT OF SHOWERS AND THUNDERSTORMS TO THE SOUTHERN 2/3RDS OF THE CWA AT LEAST INTO FRIDAY. GLASS && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1131 PM CDT SUN AUG 4 2013 EXPECTING VFR CONDITIONS TO CONTINUE TO PREVAIL ACROSS MUCH OF THE AREA...WITH THE EXCEPTIONS OF PARTS OF CENTRAL AND NORTHEAST MISSOURI AS WELL AS A SMALL PART OF WEST CENTRAL ILLINOIS. A SMALL PART OF SOUTHEAST MISSOURI...PROBABLY SOUTH OF FARMINGTON...WILL LIKELY SEE LOWERED CEILINGS AS WELL AS LOWERED VISIBILITY IN RAIN AND POSSIBLY THUNDERSTORMS LATER TONIGHT. CIGS BELOW 2000FT...AND POSSIBLY BELOW 1000FT LOOK LIKELY ACROSS CENTRAL MISSOURI AND THAT SMALL PORTION OF SOUTHEAST MISSOURI. A COMPLEX OF THUNDERSTORMS IS ALREADY MOVING INTO SOUTHWEST MISSOURI FROM KANSAS...AND DEBRIS FROM THESE STORMS WILL BE THE PRIMARY CAUSE OF THE MVFR CIGS LATER TONIGHT. THINK MOST OF THE PRECIP SHOULD STAY IN SOUTHWEST/SOUTH CENTRAL MISSOURI THOUGH. CEILINGS SHOULD RISE BACK TO VFR RANGE BY 18Z MONDAY. SPECIFICS FOR KSTL... EXPECT VFR FLIGHT CONDITIONS AND LIGHT SOUTHEAST-SOUTH SOUTHEAST FLOW TO CONTINUE TONIGHT. A COMPLEX OF THUNDERSTORMS WILL PASS WELL TO THE SOUTHWEST OF THE TERMINAL THROUGH THE NIGHT INTO MONDAY MORNING. DEBRIS CLOUDS FROM THESE STORMS WILL LIKELY CAUSE CIGS TO FALL TO LOW VFR RANGE DURING THE MORNING. THERE IS STILL SOME POSSIBILITY THAT CIGS COULD FALL BELOW 3000FT...BUT LATEST MODEL GUIDANCE HAS BEEN TRENDING HIGHER. VFR CONDITIONS ARE EXPECTED TO CONTINUE MONDAY INTO MONDAY NIGHT. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1204 AM CDT Mon Aug 5 2013 .SHORT TERM...(This Evening through Monday Night) Issued at 406 PM CDT SUN AUG 4 2013 Tonight...12Z operational models, especially the NAM, had difficulty evaluating the mesoscale features from last nights/todays MCS with double MCV...mesoscale vorticity center...structure. As one would expect the short range HRRR did a much better job with this system. The trailing MCV now moving into southeastern KS is aiding downstream scattered areas of rain from the southern CWA southward across southern MO. The latest HRRR maintains this area of precipitation through mid evening and then steadily diminishes it. Will follow this trend for the evening hours. Thunder chances look minimal owing to less than stellar instability due to the rain-cooled airmass and extensive cloud shield. Looking upstream within the monsoonal flow circulating around the Southern Plains upper high yields little if any clues for the next shortwave or disturbance aloft which could generate new convection. However, believe convection for the overnight hours lies with the increasing southwesterly low level jet that is expected to form from the Southern Plains into KS. GFS and NAM output both signal increasing moisture convergence and isentropic ascent will likely generate another convective complex. Due to the subsidence left behind from todays MCS and the models poor handling of this feature have some question as to where this convection will form. For now will place my bet on southeastern KS with the activity spreading into and across mainly the southern CWA. In addition to the rain tonight am expecting to see MVFR type fog form. Monday-Monday night...Models show no discernible disturbances embedded with the northwest flow which will affect the CWA during the daylight hours. So, rain chances are most likely tied to the morning hours and across the far southern counties where the combo of isentropic lift and a weakening low level jet aid a departing MCS. Have backed off on high temperatures by a handful of degrees as warm front not likely to move into the CWA and amount of residual cloud cover will impact surface heating. The nocturnal low-level jet is expected to reform Monday night and enhance the lift along/north of the surface front which is expected to lift northward across central/eastern KS and west central MO later in the evening. Have moderate confidence this will generate some healthy convection and will increase PoPs after midnight for the western counties. .LONG TERM...(Tuesday through Sunday) Issued at 406 PM CDT SUN AUG 4 2013 Slight northwest to almost zonal type flow regime will continue across the central US as the Hudson Bay vortex across southern Canada will deepen as it slowly progresses towards southern Ontario and the northern Great Lakes region. A shortwave trough will rotate along the periphery of this system and help to push a cold front southeastward through the Central Plains. This front will near the area by Tuesday night and will be the focus for convective development Tuesday night into Wednesday morning. The expected MCS will initially develop north of the CWA, along the front, during the afternoon and gradually make its way into the CWA as the evening progresses. The remainder of the week will see spotty precipitation chances as the Hudson Bay low gradually moves eastward and ridging remains positioned across the Rockies. A few shortwave troughs may ride the ridge and help to initiate convection across the region. Temperatures will be slightly cooler behind this front as surface high slides into the region, but will gradually warm into the mid 80s as we near the weekend. && .AVIATION...(For the 06Z TAFS through 06Z Monday Night) Issued at 1153 PM CDT SUN AUG 4 2013 Low MVFR to IFR conditions are expected to dominate the morning hours of Monday. Have left IFR conditions in through noon as there is an expectation that early morning storms to the south will be very slow to clear. Have left any mention of convection out of the terminals at this time owing to very low confidence that any storms will move that far north from the main axis of activity which has set up across southeast Kansas. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ SHORT TERM...MJ LONG TERM...PMM AVIATION...Cutter
AREA FORECAST DISCUSSION
NWS GLASGOW MT
909 PM MDT TUE AUG 6 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY... NORTHWESTERLY FLOW ALOFT CONTINUES THROUGH THURSDAY. WEATHER FOR THE NORTHERN CONUS IS DOMINATED BY A LARGE UPPER LOW OVER NORTH CENTRAL CANADA. AS THIS LOW SPINS AND MAKES SLOW PROGRESS EASTWARD OVER THE NEXT FEW DAYS...PERIODIC SHORTWAVE DISTURBANCES IN THE FLOW AROUND THE LOW PASS OVER THE MONTANA AREA. THESE DISTURBANCES BRING SUPPORT FOR SHOWERS AND THUNDERSTORMS. SHOWER ACTIVITY MOSTLY OCCURS IN THE AFTERNOONS AS DAYTIME HEATING OF THE RELATIVELY MOIST BOUNDARY LAYER CREATES CONVECTIVE INSTABILITY WHICH COMBINES WITH MODEST UPPER LEVEL FORCING FROM SHORTWAVE ACTIVITY. CURRENTLY..SOME NON-SEVERE SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED WITH THE PASSAGE OF A SHORTWAVE TONIGHT WITH A WEAKER ONE DUE LATE WEDNESDAY. THURSDAY AFTERNOON HAS A LOWER CHANCE OF CONVECTIVE ACTIVITY AS THE GFS AND NAM HAVE THE CANADA LOW BY THAT TIME FAR ENOUGH EASTWARD TO ALLOW SOME BUILDING OF HIGH PRESSURE OVER THE ROCKIES. FOR TONIGHT...THE HRRR MODEL SEEMS TO HAVE A REASONABLE HANDLE ON DEVELOPMENT FOLLOWING THE LOWER RESOLUTION MODELS IN PRODUCING AN AREA OF SHOWERS OVER THE NORTHEAST 2/3RDS OF THE CWA...WHICH DIES OUT AROUND 9PM. STRENGTH OF CONVECTION IS EXPECTED TO BE MODEST...THOUGH SOME THUNDERSTORMS WILL OCCUR...AS BOUNDARY LAYER INSTABILITY IS WEAK WITH LESS THAN 1000 J/KG OF MLCAPE AT MOST...WHICH RAPIDLY DECLINES AFTER 6PM AS THE SURFACE COOLS DIURNALLY. TEMPERATURES ARE EXPECTED TO BE MILD THROUGH THURSDAY DUE TO CLOUD COVER AND LIMITED THICKNESSES IN THE SOUTHWEST QUADRANT OF THE CANADA LOW. THERE IS ALSO A LACK OF WELL-DEFINED SURFACE FEATURES THAT WOULD LEAD TO STRONG WINDS. CURRENT SURFACE LOW EXITING THE DAKOTAS HAS KEPT NORTHWESTERLY SURFACE WINDS IN PLACE. THESE WINDS WILL BECOME LIGHTER TONIGHT AND WEDNESDAY...AND THEN MORE EASTERLY ON THURSDAY AS A THERMAL SURFACE LOW DEVELOPS OVER THE ROCKIES. MARTIN .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... THE EXTENDED PERIOD BEGINS THURSDAY NIGHT WITH HIGH PRESSURE AND A HEAT DOME OVER THE SOUTHWESTERN DESERT...WITH AN UPPER RIDGE EXTENDING NORTH ALL THE WAY UP INTO THE PACIFIC NORTHWEST. THE CLOSED UPPER LEVEL CANADIAN LOW WILL BE RETREATING EAST INTO ONTARIO...LEAVING BEHIND IN ITS WAKE ANOTHER...BUT WEAKER...TROUGH OVER THE PRAIRIE PROVINCES. THIS PATTERN WILL MAINTAIN OUR NORTHWEST FLOW ALOFT AND THE STATIONARY BOUNDARY ACROSS NORTHEAST MONTANA THROUGH MOST OF THE WEEKEND. THIS FLOW WILL NOT BE CLEAN...RESULTING IN OCCASIONAL SHORT PERIODS OF RAIN SHOWERS OR THUNDERSTORMS. THEN AS THE RIDGE ATTEMPTS TO MOVE EAST A COUPLE OF LOWS IN THE PAC-NW AND WESTERN CANADA SEND MOISTURE OVER THE DIVIDE. THIS MOISTURE AND MORE DISTURBANCES WILL TEND TO KNOCK DOWN THE RIDGE AND CONTINUE TO PRODUCE RAIN SHOWERS AND THUNDERSTORMS INTO NEXT WEEK. GUIDANCE SUGGEST WARMING TO ABOVE NORMAL...BUT THE PATTERN MIGHT RESIST THAT GUIDANCE TREND. FEW SIGNIFICANT CHANGES WERE NEEDED. SCT PREVIOUS DISCUSSION... FORECAST THROUGH THE END OF THE WEEK WILL BE INFLUENCED BY THE LINGERING EFFECTS OF THE STRONG HUDSON BAY LOW. UPPER RIDGE BUILDING NORTH ALONG THE ROCKIES WILL BE THE MAIN PLAYER FOR EARLY NEXT WEEK. MODELS SLIPPING OUT OF AGREEMENT REGARDING THE HUDSON BAY LOW AFTER IT DROPS INTO CENTRAL MANITOBA. ECMWF MOVES IT EAST FASTER THEN THE GFS BUT LEAVES A PORTION BEHIND IN SASKATCHEWAN THURSDAY NIGHT. EC CURRENTLY NOT INDICATING MUCH INFLUENCE ON THE SENSIBLE WEATHER WITH THIS FEATURE BUT THAT COULD CHANGE. NORTHWEST FLOW INTO EASTERN MONTANA ALONG WITH CANADIAN HIGH PUSHING INTO THE NORTHERN PLAINS SUGGEST A SHORT PERIOD OF DRIER WEATHER BUT AS SHORTWAVES BEGIN EJECTING OUT OF THE TROF ALONG THE WEST COAST AND THROUGH THE NORTHERN ROCKIES RIDGE...WILL SEE A RETURN OF THUNDERSTORM CHANCES. AFTER A COOL START TO THE EXTENDED PERIOD WITH THE PROXIMITY OF THE HUDSON BAY LOW...TEMPERATURES WILL WARM THROUGH THE WEEKEND AS UPPER RIDGE PUSHES OUT INTO THE NORTHERN PLAINS. EBERT && .AVIATION... VFR THROUGH THE REST OF TONIGHT. AN UPPER LEVEL RIDGE WEST OF THE DIVIDE AND A STRONG LOW PRESSURE SYSTEM OVER MANITOBA WILL MAINTAIN NORTHWEST FLOW ALOFT FOR NORTHEAST MONTANA. THESE WEATHER SYSTEMS HAVE PLACED A STATIONARY FRONT ACROSS ROUGHLY THE LOCAL TERMINALS THAT WILL BE THE FOCUS OF INTERMITTENT RAIN SHOWERS AND GENERAL THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING. BRIEF PERIODS OF LESS THAN VFR CONDITIONS ARE POSSIBLE WITH ANY THUNDERSTORMS THAT DEVELOP. WIND WILL BECOME LIGHT AND VARIABLE TONIGHT AND INTO WEDNESDAY EVENING. SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
244 PM MDT MON AUG 5 2013 .DISCUSSION... LESS ACTIVE TODAY THAN AT THIS TIME YESTERDAY. SHOWERS AND STORMS WITH LOCALLY HVY RAIN ARE STILL DEVELOPING OVER THE NORTHERN AND WESTERN HIGH TERRAIN AND EASTERN HIGH PLAINS. STORM MOTIONS ARE FASTER AND MORE TO THE NORTHEAST. LAPS PARAMETERS STILL INDICATE POTENTIAL FOR A FEW STRONG STORMS ARE FLASH FLOODING IS NOT OUT OF THE QUESTION FOR ANY AREA. RUC GUIDANCE AGAIN SHOWS ACTIVITY MERGING INTO THE RGV THIS VALLEY HOWEVER CONFIDENCE NOT AS HIGH SINCE OTHER GUIDANCE MEMBERS KEEP ALL ACTIVITY FARTHER SOUTH AND THERE IS A LESS THAN IMPRESSIVE CU FIELD OVER THE AREA ATTM. THE INTERESTINGLY THERE IS A WELL DEFINED WAVE THAT HAS DEVELOPED IN THE MONSOONAL PLUME HEADING NORTH INTO THE NM BOOTHEEL. FOR THIS REASON HAVE KEPT A LARGER THAN TYPICAL AREA OF CHANCE POPS FOR THE OVERNIGHT. THE NEXT VERY WELL DEFINED WAVE IS POISED OVER THE BAJA REGION AND THIS WILL MOVE NORTH THROUGH THE MONSOON PLUME TUESDAY. TOTAL BLENDED PWAT VALUES PER CIRA IMAGERY WITH THIS WAVE ARE IN THE 2.25-2.50 RANGE. 12Z GFS INDICATES THE MAX THETA-E WAVE ASSOCIATED WITH THIS SYSTEM WILL SLIDE OVER CENTRAL AND WESTERN NM NOW... WHICH IS A LITTLE FARTHER EAST THAN PREVIOUS RUNS. STORM MOTIONS WILL BE FASTER TO THE NE BUT FLASH FLOODING IS STILL A CONCERN. THIS UPPER WAVE WILL GET CAUGHT UP IN INCREASING WESTERLY FLOW OVER THE CENTRAL ROCKIES THEN NW FLOW OVER THE GREAT PLAINS. A BACK DOOR FRONTAL BOUNDARY WILL BE FORCED SOUTHWARD INTO THE NE PLAINS BEHIND THESE UPPER DYNAMICS. VERY MOIST UPSLOPE FLOW WILL IMPACT THE SANGRES EASTWARD ACROSS THE PLAINS AND GIVEN LATEST ROUNDS OF HEAVY RAINFALL IN THIS AREA...THE FLASH FLOOD THREAT WILL BE QUITE HIGH. WEDNESDAY NIGHT EXPECTING TO SEE A LARGE RAIN SHIELD SHIFTING SOUTHEAST OVER THE EAST...FOLLOWED BY A DRIER DAY FOR THURSDAY. TEMPS WILL BE BELOW NORMAL THROUGH THE WHOLE PERIOD. THE FRIDAY THROUGH MONDAY PERIOD LOOKS INTERESTING WITH ANOTHER MONSOON BURST POSSIBLE DURING THIS TIME OVER CENTRAL AND WESTERN NM. MODEL CONSISTENCY ON TIMING AND PLACEMENT IS NOT THE BEST SO WILL KEEP VALUES JUST AT CLIMO OR BELOW FOR NOW. GUYER && .FIRE WEATHER... UPPER HIGH WILL REMAIN CENTERED OVER PORTIONS OF TEXAS AND THE LOWER MISSISSIPPI VALLEY THROUGH TUESDAY. THE MONSOONAL MOISTURE PLUME WILL REMAIN CENTERED OVER WESTERN AND CENTRAL NEW MEXICO DURING THIS PERIOD. WETTING THUNDERSTORMS WILL BE EMBEDDED WITHIN THIS PLUME WITH HIGHER HUMIDITY. MODELS SHOWS A GRADUAL CHANGE IN THE MONSOON FLOW WEDNESDAY AND THURSDAY AS A WEAK TROUGH SWINGS ACROSS THE SOUTHERN AND CENTRAL ROCKIES. WEDNESDAY COULD BE QUITE DYNAMIC AS FAR AS AN EXPECTED DRIER TREND ACROSS THE WEST AND WETTING THUNDERSTORMS CENTRAL AND EASTERN AREAS. MODELS SHOW AN UPTICK IN THE UPPER FLOW SO THIS SHOULD TRANSLATE INTO A LITTLE STRONGER SURFACE WIND VERSUS WHAT WE HAVE HAD THE PAST SEVERAL DAYS. MIGHT BE A LITTLE LOW IN THE GRIDDED WIND FORECAST SO WILL WATCH THE TREND IN THE MODELS. A BACK DOOR COLD FRONT TIED TO A VIGOROUS LOW PRESSURE AREA SHOULD ADD TO THE THUNDERSTORM FOCUS ACROSS THE NORTHEAST. IT APPEARS THAT HUMIDITY VALUES LOWER THE MOST ACROSS THE SOUTHWEST HALF. THURSDAY LOOKS TO BE DRIER BOTH HUMIDITY AND WETTING THUNDERSTORM WISE. WINDS ALSO LOOK TO BE LIGHTER ON THURSDAY VERSUS WEDNESDAY. BOTH THE ECMWF AND GFS WEATHER MODELS SHOW THE UPPER HIGH REDEVELOPING OVER CENTRAL TEXAS ON FRIDAY. MONSOONAL MOISTURE WOULD TRY TO FLOW BACK OVER THE AREA. AS OF RIGHT NOW...RESIDUAL OR LEFTOVER MOISTURE SHOULD FOCUS WETTING THUNDERSTORM DEVELOPMENT OVER THE NORTH CENTRAL MOUNTAINS AND PORTIONS OF THE NORTHEAST PLAINS. THE PLUME OF MOISTURE SHOULD REINVIGORATE OVER WESTERN AND CENTRAL NEW MEXICO DURING THE WEEKEND. HUMIDITY VALUES WOULD TREND UP. A MONSOON BURST CONCENTRATING SIGNIFICANT MOISTURE AND STORMS WOULD BE POSSIBLE DURING THIS PERIOD. WEATHER MODELS TRY TO ELONGATE THE UPPER HIGH OVER PORTIONS OF NEW MEXICO EARLY NEXT WEEK. RESIDUAL MOISTURE WOULD BE AROUND AND CAUGHT WITHIN THIS UPPER HIGH ALTHOUGH STORMS WOULD BE MORE IN THE RECYCLE MODE VERSUS A TRUE MONSOON BURST MODE. THUS THE WETTING RAIN COVERAGE WOULD GRADUALLY DECLINE. WILL CONTINUE TO MONITOR THIS TREND. 50 && .AVIATION... 18Z TAF CYCLE BASED ON STEERING FLOW CONSIDERATIONS AND THE LATEST MODEL FORECASTS DECIDED TO GO BULLISH FOR WESTERN TERMINAL SITES LIKE GUP. DO NOT HAVE MVFR CIGS ASSOCIATED WITH THE STORMS ALTHOUGH COULD SEE SOME MTN TOP OBSCD FOR A PERIOD. MAIN CONVECTIVE ACTION SHOULD BE OUT WEST TODAY. STORMS SHOULD ALSO FIRE UP ALONG THE EAST SLOPES OF THE CENTRAL MTNS BUT THE ATMOSPHERE MAY BE A BIT WORKED OVER FROM YESTERDAY/S CONVECTION. EITHER WAY...GOING WITH SOME VCSH AT ABQ/SAF AND LVS LATER IN THE DAY. TCC AND ROW SHOULD BE UNDER VFR CONDITIONS THE NEXT 24 HOURS. 50 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 65 88 64 87 / 20 20 20 20 DULCE........................... 54 83 54 79 / 30 40 40 40 CUBA............................ 55 83 54 81 / 50 50 40 40 GALLUP.......................... 58 82 58 83 / 30 30 30 20 EL MORRO........................ 53 76 51 78 / 40 50 40 30 GRANTS.......................... 57 80 57 82 / 40 40 40 20 QUEMADO......................... 56 79 53 81 / 40 50 50 20 GLENWOOD........................ 60 84 59 86 / 30 30 30 20 CHAMA........................... 51 75 51 70 / 50 50 40 60 LOS ALAMOS...................... 60 82 58 79 / 50 40 30 50 PECOS........................... 59 79 57 75 / 40 40 40 40 CERRO/QUESTA.................... 54 79 55 75 / 40 40 40 50 RED RIVER....................... 48 71 48 67 / 50 60 60 60 ANGEL FIRE...................... 46 75 47 70 / 50 60 50 60 TAOS............................ 54 84 54 78 / 40 40 40 50 MORA............................ 54 78 55 73 / 40 50 40 60 ESPANOLA........................ 62 86 61 83 / 40 30 30 40 SANTA FE........................ 60 81 58 78 / 40 30 30 40 SANTA FE AIRPORT................ 62 86 60 84 / 40 30 30 40 ALBUQUERQUE FOOTHILLS........... 68 84 65 86 / 40 30 30 20 ALBUQUERQUE HEIGHTS............. 69 86 67 88 / 30 30 30 20 ALBUQUERQUE VALLEY.............. 65 89 66 89 / 30 30 30 20 ALBUQUERQUE WEST MESA........... 67 89 65 90 / 40 30 30 20 LOS LUNAS....................... 66 88 65 88 / 30 30 30 20 RIO RANCHO...................... 66 89 65 90 / 40 30 30 20 SOCORRO......................... 67 92 66 92 / 30 30 30 10 SANDIA PARK/CEDAR CREST......... 61 82 59 83 / 40 30 30 30 TIJERAS......................... 62 84 59 84 / 40 30 30 30 MORIARTY/ESTANCIA............... 59 84 59 84 / 40 30 30 30 CLINES CORNERS.................. 60 81 59 80 / 30 30 40 30 GRAN QUIVIRA.................... 62 84 59 82 / 40 30 40 20 CARRIZOZO....................... 65 88 64 86 / 30 30 30 10 RUIDOSO......................... 58 80 57 78 / 30 50 40 20 CAPULIN......................... 57 83 57 75 / 50 50 50 60 RATON........................... 59 88 59 79 / 50 50 40 60 SPRINGER........................ 59 88 60 81 / 40 40 30 60 LAS VEGAS....................... 58 83 58 78 / 30 50 40 50 CLAYTON......................... 67 93 66 84 / 40 20 40 60 ROY............................. 63 89 63 82 / 40 30 30 50 CONCHAS......................... 70 95 69 90 / 30 20 20 30 SANTA ROSA...................... 69 93 68 90 / 20 20 20 20 TUCUMCARI....................... 72 99 71 94 / 20 10 20 30 CLOVIS.......................... 69 97 69 93 / 10 10 10 10 PORTALES........................ 69 98 70 94 / 5 10 10 10 FORT SUMNER..................... 71 95 70 92 / 10 20 20 20 ROSWELL......................... 72 98 72 97 / 5 10 10 10 PICACHO......................... 65 89 64 89 / 10 20 20 10 ELK............................. 62 82 61 83 / 30 40 30 30 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1127 PM MDT SUN AUG 4 2013 .AVIATION... 06Z TAF CYCLE SHRA AND A FEW TSRA WILL CONTINUE ACROSS THE NORTHERN MTS THRU APPROX 10Z. MT TOPS MAY BE OCCASIONALLY OBSCURED. ELSEWHERE... OUTFLOW BOUNDARIES WILL CONTINUE TO INITIATE NEW STORMS FROM ABQ TO ONM AND EASTWARD TO CQC. THESE STORMS MAY MOVE INTO LVS BUT CONFIDENCE IS LOW ATTM. BRIEF HVY RAIN WILL LOCALLY REDUCE VSBY DOWN TO 4SM. MUCH OF THIS ACTIVITY WILL DIMINISH BY SUNRISE...THOUGH A FEW STORMS MAY DEVELOP OVER THE SW MTNS AROUND THIS TIME. ANOTHER ROUND OF SHRA AND TSRA WILL DEVELOP OVER THE HIGH TERRAIN AND NE NM BY LATE MORNING/EARLY AFTN. OUTFLOW BOUNDARY COLLISIONS WILL AGAIN HELP DEVELOP STORMS ACROSS THE LOWER ELEVATIONS BY LATE AFTN. LOCALLY HVY RAIN...SMALL HAIL AND GUSTY WINDS WILL BE THE MAIN THREATS. 34 && .PREV DISCUSSION...216 PM MDT SUN AUG 4 2013... ...INCREASED POTENTIAL FOR LOCALLY HEAVY RAINFALL THROUGH TONIGHT... RADAR TRENDS INDICATING SCATTERED TO NUMEROUS STORMS ACROSS THE HIGH TERRAIN OF CENTRAL NM. 19Z LAPS ANALYSIS SHOWS A SIGNIFICANT AMOUNT OF MOIST INSTABILITY OVER THE AREA WITH 2000-3500J/KG CAPE AND LIFTED INDICES BTWN -3 AND -6C FROM THE RGV INTO THE NE PLAINS. 700-500MB STORM MOTION VECTORS ARE NORTH NEAR 5 KTS WHICH IS MUCH SLOWER THAN YESTERDAY...SO THE HEAVY RAINFALL THREAT IS HIGHER AS WELL. PLACED MENTION OF LCL HEAVY RAIN IN GRIDS BUT WILL NOT ISSUE A FLASH FLOOD WATCH. OUTFLOW BOUNDARIES WILL ACTIVATE IN THIS REGIME TO PRODUCE MORE STORMS FOR VALLEY AREAS LATER IN THE DAY AS SHOWN BY THE RUC AND HRRR GUIDANCE. A LARGE PRECIP SHIELD IS LIKELY TO MOVE SLOWLY NORTH OVER CENTRAL NM AS WELL TONIGHT. RAISED POPS CONSIDERABLY FOR THIS REGION. MONDAY WILL BE AN ACTIVE DAY AGAIN. THE GFS INDICATES PWAT VALUES WILL TREND DOWN JUST SLIGHTLY AND THE MAIN AXIS OF INSTABILITY WILL SHIFT A LITTLE EAST ONTO THE HIGH PLAINS. STORM MOTIONS WILL BE MORE SOUTHWESTERLY AND SLOW AGAIN. THIS WILL BRING A LITTLE MORE COVERAGE TO THE EASTERN PLAINS DURING THE EVENING. WESTERN NM WILL STILL SEE VERY WEAK STORM MOTIONS WITH LCL HEAVY RAINFALL. TUESDAY IS EXPECTED TO BE ACTIVE AS WELL. AN EASTERLY WAVE NOTED ON WATER VAPOR ALONG THE WEST CENTRAL MEXICAN COAST WILL SHIFT NORTH AND IMPACT EASTERN AZ/WESTERN NM. RAISED POPS FOR TUESDAY. STEERING FLOW WILL INCREASE MORE BUT STILL REMAIN LIGHT ENOUGH FOR HEAVY RAINERS. DRIER MORE STABLE AIR WILL WORK INTO WESTERN/CENTRAL NM BEHIND THE UPPER WAVE. STORM COVERAGE WILL DIMINISH CONSIDERABLY FOR THE WEST. THIS UPPER WAVE WILL BECOME CAUGHT UP IN NORTHWEST FLOW OVER THE CENTRAL PLAINS STATES AND ENHANCE A SURFACE BACK DOOR FRONTAL BOUNDARY OVER NORTHEAST NM. THE NAM IS BULLISH WITH THE STRENGTH OF THIS SURFACE BOUNDARY AND THE COVERAGE OF STORMS. OVERALL THE PATTERN THROUGH THE REMAINDER OF THE WEEK LOOKS TO LOCK IN A VERY WELL DEFINED MONSOONAL CIRCULATION OVER CENTRAL/WESTERN NM. GUYER .FIRE WEATHER... UPPER HIGH ANCHORED OVER CENTRAL TEXAS WILL SLOWLY SHIFT TOWARD THE EAST AND SOUTH THROUGH LATE TUESDAY...BECOMING ELONGATED NEAR THE TX GULF COAST REGION BY WEDNESDAY MORNING. WELL ADVERTISED UPTICK IN THUNDERSTORM COVERAGE FOR THIS AFTERNOON HAS PANNED OUT WELL WITH STORM MOTIONS GENERALLY TOWARD THE NORTH-NORTHEAST AT 15 MPH OR LESS. OUTFLOW BOUNDARY INTERACTIONS IN THE PRESENCE OF A MUCH MORE UNSTABLE ENVIRONMENT SHOULD RESULT IN QUITE A BIT MORE THUNDERSTORM ACTIVITY IN THE VALLEYS BY MID TO LATE AFTERNOON AND INTO THE EVENING AS COMPARED TO SATURDAY...WITH THE POTENTIAL FOR HEAVY THUNDERSTORM RAINS INCREASING AND EXPANDING ACROSS THE NORTHEAST. THE UPPER FLOW REGIME WILL FAVOR LATE NIGHT OR NOCTURNAL SHOWERS FOR AREAS BETWEEN THE CONTINENTAL DIVIDE AND CENTRAL MOUNTAIN CHAIN WITH THE CENTRAL VALLEY CORRIDOR ESPECIALLY FAVORED. WELL-ESTABLISHED MONSOON PLUME ALONG THE WESTERN PERIPHERY OF THE RIDGE WILL CHANGE VERY LITTLE OVER THE NEXT 24-36 HOURS. LINGERING CLOUD COVER MONDAY MORNING MAY LIMIT EARLY DAYTIME HEATING AND THUS TOMORROW/S CROP OF THUNDERSTORMS MAY NOT BE QUITE AS WIDESPREAD AS TODAY BUT THE PATTERN WILL REMAIN FAVORABLE FOR THE WESTERN TWO-THIRDS OF THE AREA. TUESDAY WILL MARK A TRANSITION TO A RELATIVELY FASTER SW TO NE STEERING FLOW...AND POSSIBLY AN ENHANCED WINDOW OF MOISTURE/DYNAMIC FORCING ASSOCIATED WITH AN EASTERLY WAVE THAT WILL SLOWLY APPROACH THE REGION IN THE CLOCKWISE FLOW AROUND THE HIGH. WHILE MODELS SHOW THIS FEATURE TRACKING NORTH-NORTHWEST WELL TO OUR SOUTHWEST...ITS REMNANTS SHOULD EVENTUALLY WORK BACK TOWARD THE EAST AND THE FOUR CORNERS. MEDIUM RANGE GUIDANCE SHOWING SOME NICE CONSISTENCY THUS FAR AND WE WILL SEE IF THE TREND CONTINUES. OVERALL LOW CONFIDENCE IN WHAT WILL BECOME OF THIS FEATURE...HOW FAR NORTH IT MAY TRACK BUT THE MODELS ARE GENERALLY IN DECENT AGREEMENT SHOWING THE WAVE TRANSLATING EASTWARD OVER SOUTHERN COLORADO AND NORTHERN NEW MEXICO WED-WED PM. AT THE SAME TIME...A GOOD LOOKING BACKDOOR COLD FRONT IS INDICATED TO SURGE SOUTHWARD SETTING UP A POTENTIALLY VERY ACTIVE PATTERN FOR AREAS EAST OF THE CENTRAL MOUNTAIN CHAIN AND ESPECIALLY THE NORTHEAST. EXTENT OF LOWER LEVEL DRYING ACROSS THE WEST REMAINS A BIG QUESTION MARK...AS MODELS ARE QUITE AGGRESSIVE IN DRYING DEW POINTS DURING THE WED/THU PERIOD. KJ && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
222 PM EDT MON AUG 5 2013 .SYNOPSIS... HIGH PRESSURE OVER NEW YORK WILL MOVE OFF THE EAST COAST TONIGHT. AN INCREASINGLY MOIST SOUTHERLY FLOW WILL DEVELOP ON TUESDAY AND CONTINUE INTO WEDNESDAY AHEAD OF A COLD FRONT. SCATTERED SHOWERS WILL BE POSSIBLE ON TUESDAY OVER PORTIONS OF NORTHEAST PENNSYLVANIA AND CENTRAL NEW YORK...WITH SHOWERS AND THUNDERSTORMS BECOMING MORE LIKELY ON WEDNESDAY AND WEDNESDAY NIGHT AS THE COLD FRONT APPROACHES. LINGERING SHOWERS WILL BE POSSIBLE ACROSS NORTHEAST PENNSYLVANIA INTO THURSDAY AFTERNOON NEAR THE DEPARTING FRONT. && .NEAR TERM /THROUGH TUESDAY/... SFC HI PRES CNTRD OVER NY/PA THIS AFTN WILL DRIFT EWD OFF THE EAST CST TNGT. DIURNAL CU XPCTD TO DSPT LATER THIS AFTN...WITH SOME MID AND HI LVL CLDS WORKING INTO THE RGN TNGT. RUC LOOKS OVERDONE WITH RETURNING LOW LVL MSTR LATER TNGT...AND XPCT ANY CONVECTION ASSCD WITH UPSTREAM S/WV`S OVER THE GTLAKES TO DSPT/WEAKEN AS THEY MOV EWD TWDS THE RGN. K INDICES ON TUE AFTN SUGGEST BEST CHC FOR SCT CONVECTION ACRS PORTIONS OF THE WYOMING VLY INTO THE CNTRL SRN TIER AND FINGER LAKES WHERE K`S >32 AND BL LI`S ARND -1 TO -2. GFS ALSO SUGGESTS BEST CHC FOR SCT ACTIVITY WILL BE ACRS WRN ZONES ON TUE BASED ON LOW LVL CONVERGENCE AND INSTABILTY FIELDS. FOR NOW JUST INDICATED THE CHC FOR -SHRA ON TUE ACRS THESE AREAS. CLD FIELDS AVERAGED OUT TO MOSTLY CLDY...BUT WE`LL LIKELY SEE A DECENT AMT OF SUNSHINE THROUGH THE MID/UPR DECK. MAXES GNRLY M/U70S. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... CONFIDENCE FACTOR DECREASES IN THE SHORT TERM...AS DETERMINISTIC MDLS STILL SHOW DIFFS IN TIMING OF FNT AND POTNL CONVECTIVE SYSTEMS. LOW LVL MSTR WILL INCRS ON SRLY FLOW...WITH LOW CLDS PSBL ACRS THE SRN TIER AND NE PA BY WED MRNG. FOR NOW RETAINED SLGT CHC/LOW CHC POPS ON TUE NGT...INCRSNG TO LIKELY BY WED NGT WITH APRCH OF THE CDFNT. BY 12Z THU...IT APPEARS THAT THE FNT WILL JUST BE ENTERING THE FAR WRN/NW ZONES...GETTING INTO THE SRN CATSKILLS AND NE PA BY THU EVNG. SOME IMPRVMNT IS LIKELY IN THE AFTN ACRS THE FINGER LAKES...CNTRL SRN TIER AND SRN TUG ON THU AFTN...WITH CHC POPS ACRS SE ZONES CLOSER TO THE FNT. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... CHGS MADE TO EXTNDD PORTION OF THE FCST BASED ON 12Z GUIDANCE FILTERING IN. 12Z GFS BRINGS BNDRY THRU THURSDAY AND THEN IT APPEARS TO GET HUNG UP ACRS THE AREA. THIS WL SET THE STAGE FOR SFC LOW TO RIDE UP ALONG THE FRONT PER GFS AND LATEST CMC ON FRIDAY. GFS IS FURTHER NORTH THAN CMC AT THIS POINT RIDING IT NORTH ALONG THE AXIS OF THE GREAT LKS, WHEREAS CMC MVS IT ACRS NRN TIER OF PA INTO HUDSON VLY BY 06Z SATURDAY. 00Z EURO ALSO HINTING AT A WK LOW TREKKING ACRS THE AREA ON FRIDAY THO NOT AS STRONG AS GFS OR CMC. BASED ON LATEST TRENDS, HV BUMPED POPS TO BTWN 40-50% FOR FRIDAY AND DROPPED AFTN MAXES INTO THE 70S. FROPA LOOKS TO FINALLY OCCUR FRIDAY NIGHT AS SFC LOW HEADS INTO CANADIAN MARITIMES WITH DRYING HIPRES BUILDING IN AND POPS DWINDLING BY 12Z SATURDAY. NW FLOW WL FILTER IN COOL ADVECTION WITH H8 TEMPS DROPPING TO NR +10C FOR SATURDAY AFTN. CAA CONTS FOR SUNDAY AS NW FLOW RMNS OVR THE AREA THUS EXPECTING TEMPS TO BE COOLER ON SUNDAY WITH OVERALL TEMPS THRU THE PD RUNNING BLO NORMAL. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... 18Z UPDATE... HIGH PRESSURE BUILDING INTO THE AREA THIS AFTERNOON WILL RESULT IN SCT-BKN CUMULUS FIELD DIMINISHING AFTER 00Z AND LEAVING HIGH CIRRUS IN ITS WAKE. VFR CONDITIONS EXPECTED NEXT 24 HOURS UNDER HIGH PRESSURE. DRY AIRMASS WILL PREVENT MUCH IN THE THE WAY OF FOG DEVELOPING TONIGHT. WINDS LIGHT OUT OF THE NORTHWEST EARLY WILL BECOME MORE SOUTHEASTERLY TONIGHT THEN INCREASE IN SPEEDS AFTER 14Z TUESDAY. OUTLOOK... TUE AFTERNOON/TUE NIGHT...CHC MVFR SHWRS AFTER 18Z. WED/WED NIGHT...MVFR CIGS SHWRS/TSRA. THU...MVFR IN SHRA AND TSRA IMPROVING TO VFR LATE. FRI...MVFR IN SHRA/TSRA. SAT...BECOMING VFR UNDER HIGH PRESSURE && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ LONG TERM...PVN AVIATION...PVN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
318 PM EDT MON AUG 5 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE MID ATLANTIC WILL MOVE OFFSHORE TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL THROUGH MID TO LATE WEEK. && .NEAR TERM /THROUGH TUESDAY/... AS OF 300 PM MONDAY... OVERVIEW: SYNOPTIC SUBSIDENCE /HEIGHT RISES/ OVER THE MID-ATLANTIC THIS MORNING WILL WANE AND SHIFT TO NEW ENGLAND THIS AFT/TONIGHT AS AN UPPER LEVEL TROUGH PROGRESSES FURTHER NORTHEAST INTO THE CANADIAN MARITIMES. ACCORDINGLY...1021 MB SFC HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC THIS MORNING WILL WEAKEN AND SHIFT OFFSHORE THE MID- ATLANTIC COAST. AS THE SFC HIGH PROGRESSES EASTWARD AND A LIGHT S/SE RETURN FLOW DEVELOPS OVER THE WESTERN CAROLINAS THIS AFT/EVE...A STATIONARY FRONT EXTENDING EASTWARD FROM NORTHERN GA INTO CENTRAL/UPSTATE SC WILL BEGIN TO LIFT NORTH FROM UPSTATE SC INTO WESTERN NC (ALONG AND WEST OF I-77)...WITH MOISTURE SLOWLY INCREASING TONIGHT ALONG AND WEST OF THE HIGHWAY 1 CORRIDOR. TONIGHT: GIVEN THE AFOREMENTIONED MOISTURE IN ADDITION TO SEASONABLY WEAK MID-LEVEL LAPSE RATES...DIURNAL DESTABILIZATION TODAY WILL BE MARGINAL AND LARGELY CONFINED TO WESTERN PORTIONS OF THE STATE WHERE LOW-LEVEL CONVERGENCE /MOISTURE POOLING/ AND THE SLOW NORTHWARD RETREAT OF THE FRONT WILL CONTRIBUTE TO PERHAPS 250-500 J/KG MLCAPE. GRADUAL LOW-LEVEL MOISTURE RETURN OVERNIGHT WILL RESULT IN A SLOW INCREASE IN MUCAPE...PERHAPS UP TO 500 J/KG IN THE WESTERN PIEDMONT AND 1000 J/KG IN THE FOOTHILLS/MOUNTAINS BY 12Z TUE MORNING. FORCING FOR ASCENT WILL BE CONFINED TO WEAK/SHALLOW LOW-LEVEL CONVERGENCE AND UPSLOPE FLOW IN WESTERN NC THIS AFTERNOON INTO TONIGHT. ALTHOUGH THERE IS AT LEAST A POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN W/NW FLOW ALOFT THROUGH TONIGHT...19Z WV IMAGERY AND RAP DATA DO NOT SUGGEST ANY SIGNIFICANT DPVA WILL BE PRESENT. PER 19Z VIS SAT/RADAR IMAGERY INDICATING SHALLOW AGITATED CU AND A FEW BRIEF SHOWERS IN THE WEST...WILL INDICATE A SLIGHT CHANCE OF SHOWERS THROUGH THIS EVENING. INCREASINGLY MOIST LOW-LEVEL UPSLOPE FLOW AND A RELATIVELY BETTER CHANCE FOR SMALL AMPLITUDE DISTURBANCES ALOFT SHOULD RESULT IN A BETTER CHANCE FOR ISOLD/SCT SHOWERS IN THE WESTERN PIEDMONT PRIOR TO SUNRISE TUE...SUPPORTED BY THE LATEST HIGH-RES CONVECTION ALLOWING MODELS. WILL INDICATE INCREASING PRECIP CHANCES. EXPECT LOWS TONIGHT NEAR OR SLIGHTLY BELOW NORMAL...IN THE LOWER TO UPPER 60S...WARMEST IN THE WEST/SW PIEDMONT WHERE MORE CLOUD COVER AND BETTER LOW-LEVEL MOISTURE WILL BE PRESENT AND COOLEST IN THE TYPICAL AREAS OF THE NORTHERN PIEDMONT AND NE COASTAL PLAIN WHERE A DRIER AIRMASS AND LESS CLOUD COVER (AT LEAST INITIALLY) WILL PREVAIL. TUESDAY: EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER... RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE SANDHILLS AND COASTAL PLAIN. -VINCENT && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 318 PM MONDAY... TUESDAY NIGHT...APPROACH OF A WEAK MID-UPPER LEVEL DISTURBANCE COUPLED WITH AN INCREASINGLY MOIST AIR MASS WILL SUPPORT THE POTENTIAL FOR A FEW SHOWERS/ISOLATED THUNDER WELL INTO THE NIGHT...MAINLY OVER THE NW PIEDMONT. INCREASING/THICKENING CLOUD COVER AND A LIGHT SLY WIND WILL RESULT IN A FAIRLY UNIFORM TEMP FIELD OVERNIGHT. MIN TEMPS UPPER 60S TO AROUND 70. WEDNESDAY AND WEDNESDAY NIGHT...THE MID-UPPER LEVEL TROUGH TRANSLATE SLOWLY EWD TOWARD AND ACROSS THE MID ATLANTIC AND CAROLINAS WED AFTERNOON-EVENING. 12Z GFS NOT TOO IMPRESSIVE WITH ITS CONVECTIVE PARAMETERS WED AFTERNOON-EVENING ...DEPICTING MARGINAL/SLIGHT INSTABILITY AT BEST. STILL...FAVORED LOW LEVEL CONFLUENCE OVER THE WESTERN PIEDMONT DURING PRIME HEATING SUPPORT HIGH CHANCE POP IN THIS REGION....WITH POPS TAPERING TO SLIGHT CHANCE OVER THE SOUTHERN COASTAL PLAINS AND SANDHILLS. MORE CLOUDS THAN SUN WILL LIMIT NORMAL DIURNAL TEMP RISE IN THE WEST-NW WHERE MAX TEMPS EXPECTED TO BE LOWER 80S. PARTIAL SUN OVER THE SE HALF SHOULD WARM TEMPS WELL INTO THE 80S. CONSIDERABLE CLOUDINESS WEDNESDAY NIGHT WILL MAINTAIN HUMID CONDITIONS. MIN TEMPS AROUND 70/LOWER 70S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 318 PM MONDAY... THURSDAY... LINGERING MID-UPPER LEVEL TROUGH WILL MAINTAIN A DECENT THREAT FOR SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AS LOW LEVEL CONVERGENCE PROJECTED TO BE MAXIMIZED OVER OUR REGION. ONLY CAVEAT IS THAT BUILDING MID-UPPER LEVEL HEIGHTS MAY RESULT IN THE DEVELOPMENT OF A LAYER OF WARM AIR ALOFT...POSSIBLY CAPPING AIR MASS AND LIMITING CONVECTIVE DEVELOPMENT. HOWEVER CONSIDERING THE AMOUNT OF LOW LEVEL CONVERGENCE AND AVAILABLE MOISTURE SUPPORT CHANCE POPS THURSDAY. FRIDAY-SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE CHANCE-SLIGHT CHANCE POPS NW-SE ACROSS THE REGION FRIDAY WITH HIGH CHANCE POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT. SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE NORTHERN LAKES TO TRANSLATE INTO OUR REGION. TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5 DEGREES ABOVE NORMAL. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 245 PM MONDAY... 24-HR TAF PERIOD: DRY HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC WILL WEAKEN AND MOVE OFFSHORE THE DELMARVA THIS AFTERNOON INTO TONIGHT...WITH A WEAK SOUTHERLY RETURN FLOW DEVELOPING OVER THE REGION AND A SEASONABLY MOIST AIRMASS RETURNING TO CENTRAL AND WESTERN NC. MVFR CEILINGS AND ISOLD SHOWERS WILL BE POSSIBLE AT THE INT/GSO TERMINALS THIS AFT/EVE...THOUGH OVERALL PROBABILITIES WILL BE LOW AND THUNDER APPEARS UNLIKELY. PER 16-17Z VIS SAT AND RADAR IMAGERY...WILL INDICATE VCSH OR A TEMPO GROUP FOR MVFR CEILINGS AND AN ISOLD SHOWER IN THE 18-21Z TIME FRAME AT THE INT/GSO TERMINALS. OTHERWISE... EXPECT VFR CONDITIONS TO PREVAIL THROUGH MIDNIGHT. EXPECT AN INCREASING POTENTIAL FOR MVFR CEILINGS AND ISOLD TO SCT SHOWERS BETWEEN MIDNIGHT AND SUNRISE TUE MORNING AT THE INT/GSO TERMINALS... WITH ISOLD/SCT SHOWERS PERSISTING THROUGH THE REMAINDER OF THE TAF PERIOD. FURTHER EAST AT RDU/FAY/RWI...EXPECT A POTENTIAL FOR MVFR CEILINGS PRIOR TO SUNRISE TUE...WITH AN INCREASING POTENTIAL FOR ISOLD SHOWER ACTIVITY BY TUE AFTERNOON...PRIMARILY AT THE FAY/RDU TERMINALS. LOOKING AHEAD: EXPECT SUB-VFR CONDITIONS TO OCCUR PRIMARILY DURING THE MORNING (06-14Z) HOURS IN ASSOC/W LOW CEILINGS AND/OR FOG...AND DURING THE AFT/EVE HOURS (18-03Z) IN ASSOCIATION WITH ISOLD TO SCT SHOWERS AND THUNDERSTORMS TUE-FRI. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM..WSS LONG TERM...WSS AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
308 PM EDT MON AUG 5 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE MID ATLANTIC WILL MOVE OFFSHORE TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL THROUGH MID TO LATE WEEK. && .NEAR TERM /THROUGH TUESDAY/... AS OF 300 PM MONDAY... OVERVIEW: SYNOPTIC SUBSIDENCE /HEIGHT RISES/ OVER THE MID-ATLANTIC THIS MORNING WILL WANE AND SHIFT TO NEW ENGLAND THIS AFT/TONIGHT AS AN UPPER LEVEL TROUGH PROGRESSES FURTHER NORTHEAST INTO THE CANADIAN MARITIMES. ACCORDINGLY...1021 MB SFC HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC THIS MORNING WILL WEAKEN AND SHIFT OFFSHORE THE MID- ATLANTIC COAST. AS THE SFC HIGH PROGRESSES EASTWARD AND A LIGHT S/SE RETURN FLOW DEVELOPS OVER THE WESTERN CAROLINAS THIS AFT/EVE...A STATIONARY FRONT EXTENDING EASTWARD FROM NORTHERN GA INTO CENTRAL/UPSTATE SC WILL BEGIN TO LIFT NORTH FROM UPSTATE SC INTO WESTERN NC (ALONG AND WEST OF I-77)...WITH MOISTURE SLOWLY INCREASING TONIGHT ALONG AND WEST OF THE HIGHWAY 1 CORRIDOR. TONIGHT: GIVEN THE AFOREMENTIONED MOISTURE IN ADDITION TO SEASONABLY WEAK MID-LEVEL LAPSE RATES...DIURNAL DESTABILIZATION TODAY WILL BE MARGINAL AND LARGELY CONFINED TO WESTERN PORTIONS OF THE STATE WHERE LOW-LEVEL CONVERGENCE /MOISTURE POOLING/ AND THE SLOW NORTHWARD RETREAT OF THE FRONT WILL CONTRIBUTE TO PERHAPS 250-500 J/KG MLCAPE. GRADUAL LOW-LEVEL MOISTURE RETURN OVERNIGHT WILL RESULT IN A SLOW INCREASE IN MUCAPE...PERHAPS UP TO 500 J/KG IN THE WESTERN PIEDMONT AND 1000 J/KG IN THE FOOTHILLS/MOUNTAINS BY 12Z TUE MORNING. FORCING FOR ASCENT WILL BE CONFINED TO WEAK/SHALLOW LOW-LEVEL CONVERGENCE AND UPSLOPE FLOW IN WESTERN NC THIS AFTERNOON INTO TONIGHT. ALTHOUGH THERE IS AT LEAST A POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN W/NW FLOW ALOFT THROUGH TONIGHT...19Z WV IMAGERY AND RAP DATA DO NOT SUGGEST ANY SIGNIFICANT DPVA WILL BE PRESENT. PER 19Z VIS SAT/RADAR IMAGERY INDICATING SHALLOW AGITATED CU AND A FEW BRIEF SHOWERS IN THE WEST...WILL INDICATE A SLIGHT CHANCE OF SHOWERS THROUGH THIS EVENING. INCREASINGLY MOIST LOW-LEVEL UPSLOPE FLOW AND A RELATIVELY BETTER CHANCE FOR SMALL AMPLITUDE DISTURBANCES ALOFT SHOULD RESULT IN A BETTER CHANCE FOR ISOLD/SCT SHOWERS IN THE WESTERN PIEDMONT PRIOR TO SUNRISE TUE...SUPPORTED BY THE LATEST HIGH-RES CONVECTION ALLOWING MODELS. WILL INDICATE INCREASING PRECIP CHANCES. EXPECT LOWS TONIGHT NEAR OR SLIGHTLY BELOW NORMAL...IN THE LOWER TO UPPER 60S...WARMEST IN THE WEST/SW PIEDMONT WHERE MORE CLOUD COVER AND BETTER LOW-LEVEL MOISTURE WILL BE PRESENT AND COOLEST IN THE TYPICAL AREAS OF THE NORTHERN PIEDMONT AND NE COASTAL PLAIN WHERE A DRIER AIRMASS AND LESS CLOUD COVER (AT LEAST INITIALLY) WILL PREVAIL. TUESDAY: EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER... RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE SANDHILLS AND COASTAL PLAIN. -VINCENT && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 250 AM MONDAY... FOR WEDNESDAY/WEDNESDAY NIGHT: A WEAK MID LEVEL WAVE EXTENDING FROM LAKE ERIE TO KY/TN EARLY WED WILL SHIFT EASTWARD ACROSS THE APPALACHIANS TO THE NORTHEAST STATES THROUGH WED NIGHT. THIS WAVE WILL SERVE AS A WEAK/DIFFUSE WARM FRONT ALOFT AS THE TX RIDGE BUILDS A BIT TO THE NE AND THE FAST WESTERLIES OVER THE NRN TIER OF THE CONUS FLATTENS OUT. THE SOUTHERN PORTION OF THIS WAVE APPEARS TO CONSIST OF ENERGY EMANATING FROM MCS ACTIVITY OVER MO EARLY TUE... SO EXPECT THIS MCV TO BRING COPIOUS MID LEVEL CLOUDINESS WEDNESDAY... RESULTING IN MOSTLY CLOUDY TO CLOUDY SKIES AREAWIDE. THE INCREASING SOUTHERLY LOW LEVEL FLOW SHOULD BE MOST PRONOUNCED OVER THE MOUNTAINS INTO THE WRN CWA... WHERE LOW LEVEL MASS CONVERGENCE WILL BE ENHANCED ALONG/AHEAD OF THE INCOMING 850 MB FRONT. FORECAST SOUNDINGS SHOW GREATER MOISTURE THROUGH THE COLUMN IN THE WRN CWA WHILE THE AIR BENEATH 600 MB IS DRIER IN THE EAST... AND THE MID LEVEL WARMING CENTERED AROUND 500 MB SHOULD LIMIT INSTABILITY... WITH MODELS GENERALLY SHOWING 1000 J/KG OR LESS IN THE WRN CWA ONLY. BUT THE INCREASING PW VALUES TO AROUND 2 INCHES IN THIS AREA WARRANT GOOD CHANCE POPS IN THE WRN CWA RANGING TO JUST SLIGHT CHANCE IN THE FAR ERN CWA... TAPERING OFF BY LATE EVENING. THICKNESSES ABOUT 10 M BELOW NORMAL WITH PLENTY OF CLOUDS SUPPORT HIGHS AROUND A CATEGORY BELOW NORMAL... 83-87. CONTINUED MOSTLY CLOUDY OVERNIGHT AS THE SKY BEHIND SLOWLY-DEPARTING HIGH-BASED STRATOCU FILLS IN WITH FOG/STRATUS OVERNIGHT. LOWS 68-72. FOR THURSDAY/THURSDAY NIGHT: RELATIVELY DRY. FAST AND FLAT FLOW CONTINUES THU MORNING FROM THE EASTERN ROCKIES AND GREAT PLAINS EASTWARD THROUGH THE OH VALLEY AND GREAT LAKES TO THE MIDATLANTIC AND NORTHEAST. MEANWHILE THE TX RIDGE EXPANDS EASTWARD OVER THE GULF AND SOUTHEAST STATES... A REACTION TO A VORTICITY MAX MOVING FROM THE FOUR CORNERS EAST INTO THE TROUGH BASE OF A STRONG VORTEX CENTERED OVER THE MANITOBA/ONTARIO BORDER. THIS WILL RESULT IN VERY WEAK AND ILL-DEFINED MID LEVEL FLOW OVER NC... NOTED ON NAM/GFS FORECAST SOUNDINGS DEPICTING CONSIDERABLE DRYING ALOFT. AT THE SURFACE... A STRENGTHENING FRONTAL ZONE FROM OK THROUGH THE OH VALLEY TO NEW ENGLAND WILL MOVE LITTLE THROUGH THU NIGHT AS IT WAITS FOR THE CANADA VORTEX TO AMPLIFY SLIGHTLY STARTING FRIDAY... AND THE WEAK LEE TROUGH WILL HOLD OVER THE VA/NC PIEDMONT. THE BETTER LOW LEVEL MOISTURE FLUX WILL BE DEFLECTED TO OUR WEST AND NORTH THROUGH THU NIGHT... IN THE BETTER WARM/MOIST CONVEYOR ZONE... AND PW OVER NC SLIPS TO A RELATIVE MINIMUM. HAVE HELD POPS AT JUST LOW CHANCE MAINLY ACROSS THE FAR WEST AND NRN CWA... ON THE EDGE OF THE RIDGE CORE. WITH FEWER CLOUDS AND AN ASSOCIATED UPTICK OF THICKNESSES TO JUST A BIT BELOW NORMAL... EXPECT HIGHS OF 86-90. SHOULD SEE INCREASING AND THICKENING/LOWERING MID CLOUDS THU NIGHT AS WEAK WESTERLY STEERING FLOW BRINGS BLOWOFF CLOUDS FROM OH VALLEY AND MID MISS VALLEY CONVECTION. LOWS 69-74. -GIH && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 220 AM MONDAY... STILL APPEARS THAT WE`LL SEE WET WEATHER FRIDAY/SATURDAY WITH SOME IMPROVEMENT POSSIBLE FOR SUNDAY. THE CANADIAN VORTEX WOBBLES EASTWARD ACROSS ONTARIO TO CENTRAL QUEBEC DURING THIS TIME FRAME... RESULTING IN A SLIGHT SOUTHWARD DIP TO THE WESTERLIES AND EVENTUAL EVOLUTION TO A WNW STEERING FLOW OVER NC BY SUNDAY. THE SURFACE FRONT ACROSS THE OH VALLEY AND NORTHEAST STATES EARLY FRIDAY BECOMES MORE E/W ORIENTED IN RESPONSE TO THIS EASTWARD MOVEMENT OF THE SHALLOW LONGWAVE TROUGH... AND THE LEE TROUGH SHARPENS OVER CENTRAL VA/NC AS BOTH 850 MB WINDS AND PW VALUES INCREASE WITHIN THE ENCROACHING WARM/MOIST CONVEYOR ZONE. EXPECT ABOVE-NORMAL LOWS AND SLIGHTLY BELOW-NORMAL HIGHS FRIDAY/SATURDAY AS WARM THICKNESSES ARE OFFSET BY CLOUDS AND A GOOD CHANCE OF SHOWERS/STORMS. GFS/ECMWF PUSH THE SURFACE FRONT TO SC AND ERN NC BY SUNDAY AS THE AXIS OF THE BROAD LONGWAVE TROUGH SHIFTS OVERHEAD AND JUST TO OUR EAST. WILL RETAIN LOW CHANCE POPS AREAWIDE BUT A LITTLE HIGHER IN THE EAST/SOUTH AS THE FRONT COULD HANG UP IN THE VICINITY. TEMPS NEAR TO SLIGHTLY BELOW NORMAL... ALTHOUGH THIS (ALONG WITH THE SURFACE FRONT POSITION ON SUNDAY) IS FAR FROM CERTAIN. -GIH && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 245 PM MONDAY... 24-HR TAF PERIOD: DRY HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC WILL WEAKEN AND MOVE OFFSHORE THE DELMARVA THIS AFTERNOON INTO TONIGHT...WITH A WEAK SOUTHERLY RETURN FLOW DEVELOPING OVER THE REGION AND A SEASONABLY MOIST AIRMASS RETURNING TO CENTRAL AND WESTERN NC. MVFR CEILINGS AND ISOLD SHOWERS WILL BE POSSIBLE AT THE INT/GSO TERMINALS THIS AFT/EVE...THOUGH OVERALL PROBABILITIES WILL BE LOW AND THUNDER APPEARS UNLIKELY. PER 16-17Z VIS SAT AND RADAR IMAGERY...WILL INDICATE VCSH OR A TEMPO GROUP FOR MVFR CEILINGS AND AN ISOLD SHOWER IN THE 18-21Z TIME FRAME AT THE INT/GSO TERMINALS. OTHERWISE... EXPECT VFR CONDITIONS TO PREVAIL THROUGH MIDNIGHT. EXPECT AN INCREASING POTENTIAL FOR MVFR CEILINGS AND ISOLD TO SCT SHOWERS BETWEEN MIDNIGHT AND SUNRISE TUE MORNING AT THE INT/GSO TERMINALS... WITH ISOLD/SCT SHOWERS PERSISTING THROUGH THE REMAINDER OF THE TAF PERIOD. FURTHER EAST AT RDU/FAY/RWI...EXPECT A POTENTIAL FOR MVFR CEILINGS PRIOR TO SUNRISE TUE...WITH AN INCREASING POTENTIAL FOR ISOLD SHOWER ACTIVITY BY TUE AFTERNOON...PRIMARILY AT THE FAY/RDU TERMINALS. LOOKING AHEAD: EXPECT SUB-VFR CONDITIONS TO OCCUR PRIMARILY DURING THE MORNING (06-14Z) HOURS IN ASSOC/W LOW CEILINGS AND/OR FOG...AND DURING THE AFT/EVE HOURS (18-03Z) IN ASSOCIATION WITH ISOLD TO SCT SHOWERS AND THUNDERSTORMS TUE-FRI. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM..SMITH/HARTFIELD LONG TERM...HARTFIELD AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1136 AM EDT MON AUG 5 2013 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE MID ATLANTIC WILL MOVE OFFSHORE TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL THROUGH MID TO LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1130 AM MONDAY... OVERVIEW: SYNOPTIC SUBSIDENCE /HEIGHT RISES/ OVER THE MID-ATLANTIC EARLY THIS MORNING WILL WANE AND SHIFT TO NEW ENGLAND THIS AFT/EVE AS AN UPPER LEVEL TROUGH PROGRESSES FURTHER NORTHEAST INTO THE CANADIAN MARITIMES. ACCORDINGLY...1021 MB SFC HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC THIS MORNING WILL WEAKEN AND SHIFT OFFSHORE THE MID- ATLANTIC COAST THIS AFTERNOON INTO TONIGHT. AS THE SFC HIGH PROGRESSES EASTWARD AND A LIGHT S/SE RETURN FLOW DEVELOPS OVER THE WESTERN CAROLINAS THIS AFT/EVE...A STATIONARY FRONT EXTENDING EASTWARD FROM NORTHERN GA INTO CENTRAL/UPSTATE SC WILL BEGIN TO LIFT NORTH FROM UPSTATE SC INTO WESTERN NC (ALONG AND WEST OF I-77)... WITH MOISTURE SLOWLY INCREASING TONIGHT ALONG AND WEST OF THE HIGHWAY 1 CORRIDOR. SFC DEWPOINTS WILL RANGE FROM THE MID/UPPER 50S (EAST) TO LOWER/MID 60S (WEST/SW) THIS AFTERNOON. PRECIPITATION CHANCES: GIVEN THE AFOREMENTIONED MOISTURE IN ADDITION TO SEASONABLY WEAK MID-LEVEL LAPSE RATES...DIURNAL DESTABILIZATION TODAY WILL BE MARGINAL AND LARGELY CONFINED TO SOUTHWEST PORTIONS OF THE STATE WHERE LOW-LEVEL CONVERGENCE /MOISTURE POOLING/ AND THE SLOW NORTHWARD RETREAT OF THE FRONT WILL CONTRIBUTE TO PERHAPS 250-500 J/KG MLCAPE. GRADUAL LOW-LEVEL MOISTURE RETURN OVERNIGHT WILL RESULT IN A SLOW INCREASE IN MUCAPE...PERHAPS UP TO 500 J/KG IN THE WESTERN PIEDMONT AND 1000 J/KG IN THE FOOTHILLS/MOUNTAINS BY 12Z TUE MORNING. FORCING FOR ASCENT WILL BE CONFINED TO WEAK/SHALLOW LOW-LEVEL CONVERGENCE AND UPSLOPE FLOW IN WESTERN NC THIS AFTERNOON INTO TONIGHT. ALTHOUGH THERE IS AT LEAST A POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN W/NW FLOW ALOFT THROUGH TONIGHT...15Z WV IMAGERY AND RAP DATA DO NOT SUGGEST ANY SIGNIFICANT DPVA WILL BE PRESENT. PER 15Z VIS SAT IMAGERY INDICATING SHALLOW AGITATED CU IN THE WEST...A FEW SPRINKLES OR PERHAPS AN ISOLD SHOWER CANNOT BE COMPLETELY RULED OUT IN THE TRIAD OR SW PIEDMONT THIS AFTERNOON... THOUGH PROBS ARE TOO LOW TO WARRANT MENTION IN THE FORECAST. WITH THE ABOVE IN MIND...WILL CONTINUE TO INDICATE DRY CONDITIONS THROUGH MIDNIGHT. INCREASINGLY MOIST LOW-LEVEL UPSLOPE FLOW AND A RELATIVELY BETTER CHANCE FOR SMALL AMPLITUDE DISTURBANCES ALOFT MAY RESULT IN PERIODIC DRIZZLE OR VERY LIGHT RAIN IN THE FAR WESTERN PIEDMONT PRIOR TO SUNRISE TUE...PERHAPS ISOLD TO SCATTERED SHOWER ACTIVITY ALONG AND WEST OF I-77. WILL INDICATE A SLIGHT CHANCE OF SHOWERS IN THE TRIAD AFTER MIDNIGHT. TEMPERATURES: EXPECT HIGHS NEAR OR A FEW DEGREES BELOW NORMAL IN THE LOWER/MID 80S NW PIEDMONT (MORE CLOUD COVER) TO MID/UPPER 80S IN THE SANDHILLS AND SE COASTAL PLAIN (LESS CLOUD COVER). EXPECT LOWS TONIGHT NEAR OR SLIGHTLY BELOW NORMAL...IN THE LOWER TO UPPER 60S...WARMEST IN THE WEST/SW PIEDMONT WHERE MORE CLOUD COVER AND BETTER LOW-LEVEL MOISTURE WILL BE PRESENT AND COOLEST IN THE TYPICAL AREAS OF THE NORTHERN PIEDMONT AND NE COASTAL PLAIN WHERE A DRIER AIRMASS AND LESS CLOUD COVER (AT LEAST INITIALLY) WILL PREVAIL. -VINCENT && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 250 AM MONDAY... TUESDAY AND TUESDAY NIGHT... HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MAINTAIN WEAK INFLUENCE OVER THE FAR EASTERN PORTIONS OF THE AREA...WHILE MOIST SOUTHERLY FLOW CONTINUES TO TAKE HOLD ACROSS MOST OF CENTRAL NC. HOWEVER...DEWPOINTS ARE FORECAST TO HOLD IN THE MID AND UPPER 60S...LEADING TO LIMITED DESTABILIZATION. ADDITIONAL FORCING IS TOUGH TO PICK OUT IN MODEL GUIDANCE...WITH DISTURBANCES IN THE NORTHWESTERLY UPPER LEVEL FLOW EXPECTED TO MOSTLY PASS TO OUR NORTH AND NO REAL SIGN OF A LEE TROUGH UNTIL LATER IN THE WEEK. WILL KEEP A CHANCE OF SHOWERS AND STORMS IN THE NORTHWEST PIEDMONT LATE TUESDAY AS DIFFERENTIAL HEATING CONVECTION OVER THE MOUNTAINS MAY TRY TO PUSH EAST INTO THE PIEDMONT. HIGHS A COUPLE DEGREES WARMER THAN MONDAY IN THE 84-88 RANGE. TUESDAY NIGHT LOWS IN THE MID TO UPPER 60S. -SMITH FOR WEDNESDAY/WEDNESDAY NIGHT: A WEAK MID LEVEL WAVE EXTENDING FROM LAKE ERIE TO KY/TN EARLY WED WILL SHIFT EASTWARD ACROSS THE APPALACHIANS TO THE NORTHEAST STATES THROUGH WED NIGHT. THIS WAVE WILL SERVE AS A WEAK/DIFFUSE WARM FRONT ALOFT AS THE TX RIDGE BUILDS A BIT TO THE NE AND THE FAST WESTERLIES OVER THE NRN TIER OF THE CONUS FLATTENS OUT. THE SOUTHERN PORTION OF THIS WAVE APPEARS TO CONSIST OF ENERGY EMANATING FROM MCS ACTIVITY OVER MO EARLY TUE... SO EXPECT THIS MCV TO BRING COPIOUS MID LEVEL CLOUDINESS WEDNESDAY... RESULTING IN MOSTLY CLOUDY TO CLOUDY SKIES AREAWIDE. THE INCREASING SOUTHERLY LOW LEVEL FLOW SHOULD BE MOST PRONOUNCED OVER THE MOUNTAINS INTO THE WRN CWA... WHERE LOW LEVEL MASS CONVERGENCE WILL BE ENHANCED ALONG/AHEAD OF THE INCOMING 850 MB FRONT. FORECAST SOUNDINGS SHOW GREATER MOISTURE THROUGH THE COLUMN IN THE WRN CWA WHILE THE AIR BENEATH 600 MB IS DRIER IN THE EAST... AND THE MID LEVEL WARMING CENTERED AROUND 500 MB SHOULD LIMIT INSTABILITY... WITH MODELS GENERALLY SHOWING 1000 J/KG OR LESS IN THE WRN CWA ONLY. BUT THE INCREASING PW VALUES TO AROUND 2 INCHES IN THIS AREA WARRANT GOOD CHANCE POPS IN THE WRN CWA RANGING TO JUST SLIGHT CHANCE IN THE FAR ERN CWA... TAPERING OFF BY LATE EVENING. THICKNESSES ABOUT 10 M BELOW NORMAL WITH PLENTY OF CLOUDS SUPPORT HIGHS AROUND A CATEGORY BELOW NORMAL... 83-87. CONTINUED MOSTLY CLOUDY OVERNIGHT AS THE SKY BEHIND SLOWLY-DEPARTING HIGH-BASED STRATOCU FILLS IN WITH FOG/STRATUS OVERNIGHT. LOWS 68-72. FOR THURSDAY/THURSDAY NIGHT: RELATIVELY DRY. FAST AND FLAT FLOW CONTINUES THU MORNING FROM THE EASTERN ROCKIES AND GREAT PLAINS EASTWARD THROUGH THE OH VALLEY AND GREAT LAKES TO THE MIDATLANTIC AND NORTHEAST. MEANWHILE THE TX RIDGE EXPANDS EASTWARD OVER THE GULF AND SOUTHEAST STATES... A REACTION TO A VORTICITY MAX MOVING FROM THE FOUR CORNERS EAST INTO THE TROUGH BASE OF A STRONG VORTEX CENTERED OVER THE MANITOBA/ONTARIO BORDER. THIS WILL RESULT IN VERY WEAK AND ILL-DEFINED MID LEVEL FLOW OVER NC... NOTED ON NAM/GFS FORECAST SOUNDINGS DEPICTING CONSIDERABLE DRYING ALOFT. AT THE SURFACE... A STRENGTHENING FRONTAL ZONE FROM OK THROUGH THE OH VALLEY TO NEW ENGLAND WILL MOVE LITTLE THROUGH THU NIGHT AS IT WAITS FOR THE CANADA VORTEX TO AMPLIFY SLIGHTLY STARTING FRIDAY... AND THE WEAK LEE TROUGH WILL HOLD OVER THE VA/NC PIEDMONT. THE BETTER LOW LEVEL MOISTURE FLUX WILL BE DEFLECTED TO OUR WEST AND NORTH THROUGH THU NIGHT... IN THE BETTER WARM/MOIST CONVEYOR ZONE... AND PW OVER NC SLIPS TO A RELATIVE MINIMUM. HAVE HELD POPS AT JUST LOW CHANCE MAINLY ACROSS THE FAR WEST AND NRN CWA... ON THE EDGE OF THE RIDGE CORE. WITH FEWER CLOUDS AND AN ASSOCIATED UPTICK OF THICKNESSES TO JUST A BIT BELOW NORMAL... EXPECT HIGHS OF 86-90. SHOULD SEE INCREASING AND THICKENING/LOWERING MID CLOUDS THU NIGHT AS WEAK WESTERLY STEERING FLOW BRINGS BLOWOFF CLOUDS FROM OH VALLEY AND MID MISS VALLEY CONVECTION. LOWS 69-74. -GIH && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 220 AM MONDAY... STILL APPEARS THAT WE`LL SEE WET WEATHER FRIDAY/SATURDAY WITH SOME IMPROVEMENT POSSIBLE FOR SUNDAY. THE CANADIAN VORTEX WOBBLES EASTWARD ACROSS ONTARIO TO CENTRAL QUEBEC DURING THIS TIME FRAME... RESULTING IN A SLIGHT SOUTHWARD DIP TO THE WESTERLIES AND EVENTUAL EVOLUTION TO A WNW STEERING FLOW OVER NC BY SUNDAY. THE SURFACE FRONT ACROSS THE OH VALLEY AND NORTHEAST STATES EARLY FRIDAY BECOMES MORE E/W ORIENTED IN RESPONSE TO THIS EASTWARD MOVEMENT OF THE SHALLOW LONGWAVE TROUGH... AND THE LEE TROUGH SHARPENS OVER CENTRAL VA/NC AS BOTH 850 MB WINDS AND PW VALUES INCREASE WITHIN THE ENCROACHING WARM/MOIST CONVEYOR ZONE. EXPECT ABOVE-NORMAL LOWS AND SLIGHTLY BELOW-NORMAL HIGHS FRIDAY/SATURDAY AS WARM THICKNESSES ARE OFFSET BY CLOUDS AND A GOOD CHANCE OF SHOWERS/STORMS. GFS/ECMWF PUSH THE SURFACE FRONT TO SC AND ERN NC BY SUNDAY AS THE AXIS OF THE BROAD LONGWAVE TROUGH SHIFTS OVERHEAD AND JUST TO OUR EAST. WILL RETAIN LOW CHANCE POPS AREAWIDE BUT A LITTLE HIGHER IN THE EAST/SOUTH AS THE FRONT COULD HANG UP IN THE VICINITY. TEMPS NEAR TO SLIGHTLY BELOW NORMAL... ALTHOUGH THIS (ALONG WITH THE SURFACE FRONT POSITION ON SUNDAY) IS FAR FROM CERTAIN. -GIH && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 710 AM MONDAY... A COLD FRONT HAS PUSHED SOUTH THROUGH THE AREA...WITH DRIER AIR NOW SPREADING ACROSS THE AREA AS HIGH PRESSURE BUILDS IN FROM THE NORTH. THIS WILL LEAD TO A LIGHT/VARIABLE WIND AND VFR CONDITIONS TODAY. THE HIGH PRESSURE WILL SHIFT OFFSHORE TONIGHT...ALLOWING SOUTHERLY RETURN FLOW TO DEVELOP AND MOISTURE TO INCREASE ACROSS THE WESTERN PORTIONS OF THE AREA. HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN VFR..WITH CLOUD DECKS AT OR ABOVE 3500 FT. OUTLOOK... AS MOISTURE INCREASES THIS WEEK...EARLY MORNING STRATUS/FOG POTENTIAL WILL ALSO INCREASE...WITH AFTERNOON SHOWERS AND STORMS POSSIBLE EACH DAY. THE MOST ACTIVE PERIODS FOR SHOWERS/STORMS APPEAR TO WEDNESDAY AFTERNOON AND FRIDAY/SATURDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM..SMITH/HARTFIELD LONG TERM...HARTFIELD AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
101 PM CDT MON AUG 5 2013 .UPDATE... ISSUED AT 1250 PM CDT MON AUG 5 2013 CLOUDS CONTINUE TO SLOWLY DIMINISH ACROSS THE AREA BUT IT WILL BE HIGHLY VARIABLE AS FAR AS TIMING GOES. THE FAR NW FA HAS CLEARED OUT SO WOULD EXPECT THE COOPERSTOWN...KGFK AND KHCO AREAS TO THIN OUT IN THE NEXT HOUR OR SO. IT WILL STILL TAKE LONGEST FOR THE EASTERN FA TO CLEAR SO IT SHOULD STAY THE COOLEST THERE FOR HIGH TEMPS. REST OF THE AREA WILL SEE A SLOW TEMP RECOVERY AS IT WILL TAKE SOME SUN TO REACH HIGHS IN THE 70S. THEREFORE IT WILL LIKELY BE A LATE AFTERNOON HIGH FOR MOST AREAS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 SURFACE TROUGH WILL CONTINUE TO PROPAGATE THROUGH THE FA. SCATTERED SHOWERS ACROSS THE EASTERN FA SHOULD BE EAST OF THE REGION BY 12Z. WEAK HIGH PRESSURE WILL MOVE INTO THE REGION. THE MAIN CHALLENGE FOR TODAY WILL BE CLOUDS AND ASSOCIATED TEMPERATURES. THERE IS AN AREA OF LOW CLOUDS BEHIND THE SURFACE TROUGH...ALONG THE INTERNATIONAL BORDER. THIS AREA OF CLOUDS HAS BEEN ADVECTING SOUTHWARD OVER THE PAST FEW HOURS...AND THE LATEST RAP GUIDANCE INDICATES THAT THIS TREND WILL CONTINUE. FOLLOWING THIS GUIDANCE MOST AREAS (EXCEPT PORTIONS OF SOUTHEAST NORTH DAKOTA) WILL LIKELY BE MOSTLY CLOUDY INTO AT LEAST THE EARLY AFTERNOON HOURS. THE THOUGHT IS THAT THE CLOUDS SHOULD BEGIN TO DISSIPATE ENOUGH BY MID-LATE AFTERNOON FOR MAX TEMPS TO BE ABLE TO REACH INTO THE MID-UPPER 70S. THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE TROUGH/COLD FRONT WILL MOVE THROUGH THE REGION TONIGHT INTO TUESDAY. FORCING AND INSTABILITY APPEAR TO BE STRONGER THAN THIS PAST SYSTEM...WHICH COULD LEAD TO MORE WIDESPREAD ACTIVITY. THE BEST SEVERE POTENTIAL WILL BE SOUTH OF THE FA WHERE INSTABILITY IS STRONGEST. HOWEVER...DEEP LAYER SHEAR WILL BE STRONG AND A FEW STRONGER STORMS WOULD SEEM POSSIBLE (ESPECIALLY TUESDAY AFTERNOON ACROSS SE ND INTO WC MN WHERE THE SFC FRONT WILL BE LOCATED DURING PEAK HEATING). .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 TUESDAY NIGHT-WEDNESDAY NIGHT...HIGH PRESSURE WILL AGAIN MOVE INTO THE REGION WHICH SHOULD LEAD TO MOSTLY DRY CONDITIONS. THURSDAY-SUNDAY NIGHT...00 UTC GFS/ECMWF SHOW SAME BASIC SYNOPTIC PATTERN...BUT DIFFER ON THE SPEED AT WHICH THE CLOSED CANADIAN LOW EJECTS INTO QUEBEC. THE ECMWF IS QUICKER THAN THE GFS AND THIS ALLOWS ANOTHER PACIFIC SHORT-WAVE TO MOVE INTO THE NORTHERN PLAINS NEXT WEEKEND. THE SLOWER GFS MAINTAINS DRY NORTHWEST FLOW ACROSS THE FORECAST AREA. GIVEN MODEL DIFFERENCES...WILL KEEP A MAINLY DRY FORECAST FRIDAY AND BEYOND. BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE THURSDAY AS ANOTHER COLD FRONT SWEEPS ACROSS THE REGION. COLD POOL ALOFT ASSOCIATED WITH DEEP CLOSED LOW WILL KEEP TEMPERATURES WELL BELOW MID-AUGUST NORMALS. HIGHS THURSDAY/ FRIDAY WILL STRUGGLE TO BREAK 70 DEGREES IN PLACES. A GRADUAL WARM-UP IS EXPECTED INTO THE WEEKEND...BUT STILL 5 TO 10 DEGREES COOLER THAN NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 101 PM CDT MON AUG 5 2013 MFVR CIGS TO CONTINUE TO LIFT AND SCT OUT THIS AFTERNOON IN THE VALLEY AND EVENING AT BJI. VFR OVERNIGHT WITH A POSSIBILITY OF SOME THUNDER IN THE DVL BSN. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...GODON SHORT TERM...TG LONG TERM...TG/ROGERS AVIATION...JK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1250 PM CDT MON AUG 5 2013 .UPDATE... ISSUED AT 1250 PM CDT MON AUG 5 2013 CLOUDS CONTINUE TO SLOWLY DIMINISH ACROSS THE AREA BUT IT WILL BE HIGHLY VARIABLE AS FAR AS TIMING GOES. THE FAR NW FA HAS CLEARED OUT SO WOULD EXPECT THE COOPERSTOWN...KGFK AND KHCO AREAS TO THIN OUT IN THE NEXT HOUR OR SO. IT WILL STILL TAKE LONGEST FOR THE EASTERN FA TO CLEAR SO IT SHOULD STAY THE COOLEST THERE FOR HIGH TEMPS. REST OF THE AREA WILL SEE A SLOW TEMP RECOVERY AS IT WILL TAKE SOME SUN TO REACH HIGHS IN THE 70S. THEREFORE IT WILL LIKELY BE A LATE AFTERNOON HIGH FOR MOST AREAS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 SURFACE TROUGH WILL CONTINUE TO PROPAGATE THROUGH THE FA. SCATTERED SHOWERS ACROSS THE EASTERN FA SHOULD BE EAST OF THE REGION BY 12Z. WEAK HIGH PRESSURE WILL MOVE INTO THE REGION. THE MAIN CHALLENGE FOR TODAY WILL BE CLOUDS AND ASSOCIATED TEMPERATURES. THERE IS AN AREA OF LOW CLOUDS BEHIND THE SURFACE TROUGH...ALONG THE INTERNATIONAL BORDER. THIS AREA OF CLOUDS HAS BEEN ADVECTING SOUTHWARD OVER THE PAST FEW HOURS...AND THE LATEST RAP GUIDANCE INDICATES THAT THIS TREND WILL CONTINUE. FOLLOWING THIS GUIDANCE MOST AREAS (EXCEPT PORTIONS OF SOUTHEAST NORTH DAKOTA) WILL LIKELY BE MOSTLY CLOUDY INTO AT LEAST THE EARLY AFTERNOON HOURS. THE THOUGHT IS THAT THE CLOUDS SHOULD BEGIN TO DISSIPATE ENOUGH BY MID-LATE AFTERNOON FOR MAX TEMPS TO BE ABLE TO REACH INTO THE MID-UPPER 70S. THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE TROUGH/COLD FRONT WILL MOVE THROUGH THE REGION TONIGHT INTO TUESDAY. FORCING AND INSTABILITY APPEAR TO BE STRONGER THAN THIS PAST SYSTEM...WHICH COULD LEAD TO MORE WIDESPREAD ACTIVITY. THE BEST SEVERE POTENTIAL WILL BE SOUTH OF THE FA WHERE INSTABILITY IS STRONGEST. HOWEVER...DEEP LAYER SHEAR WILL BE STRONG AND A FEW STRONGER STORMS WOULD SEEM POSSIBLE (ESPECIALLY TUESDAY AFTERNOON ACROSS SE ND INTO WC MN WHERE THE SFC FRONT WILL BE LOCATED DURING PEAK HEATING). .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 TUESDAY NIGHT-WEDNESDAY NIGHT...HIGH PRESSURE WILL AGAIN MOVE INTO THE REGION WHICH SHOULD LEAD TO MOSTLY DRY CONDITIONS. THURSDAY-SUNDAY NIGHT...00 UTC GFS/ECMWF SHOW SAME BASIC SYNOPTIC PATTERN...BUT DIFFER ON THE SPEED AT WHICH THE CLOSED CANADIAN LOW EJECTS INTO QUEBEC. THE ECMWF IS QUICKER THAN THE GFS AND THIS ALLOWS ANOTHER PACIFIC SHORT-WAVE TO MOVE INTO THE NORTHERN PLAINS NEXT WEEKEND. THE SLOWER GFS MAINTAINS DRY NORTHWEST FLOW ACROSS THE FORECAST AREA. GIVEN MODEL DIFFERENCES...WILL KEEP A MAINLY DRY FORECAST FRIDAY AND BEYOND. BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE THURSDAY AS ANOTHER COLD FRONT SWEEPS ACROSS THE REGION. COLD POOL ALOFT ASSOCIATED WITH DEEP CLOSED LOW WILL KEEP TEMPERATURES WELL BELOW MID-AUGUST NORMALS. HIGHS THURSDAY/ FRIDAY WILL STRUGGLE TO BREAK 70 DEGREES IN PLACES. A GRADUAL WARM-UP IS EXPECTED INTO THE WEEKEND...BUT STILL 5 TO 10 DEGREES COOLER THAN NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1250 PM CDT MON AUG 5 2013 WILL BE COMING SOON. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...GODON SHORT TERM...TG LONG TERM...TG/ROGERS AVIATION...JK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
945 AM CDT MON AUG 5 2013 .UPDATE... ISSUED AT 944 AM CDT MON AUG 5 2013 LOOKS LIKE IT WILL BE A CLOUDY START TO THE DAY WITH THE MAIN QUESTION BEING HOW FAST AND WHERE CLEARING WILL OCCUR. ALREADY SEEING SOMEWHAT OF A CLEARING LINE JUST NORTH OF THE CANADIAN BORDER WHICH SHOULD SLOWLY DROP INTO OUR NORTH BY LATER THIS MORNING. SHOULD ALSO BE SOME DECREASING CLOUDS ACROSS THE WEST BY LATE MORNING BUT THE EAST MAY BE STUCK UNDER THE CLOUDS THE LONGEST. THIS WILL IMPACT TEMPS BUT NOT MAKE ANY ADJUSTMENTS THERE UNTIL THERE IS A BETTER IDEA TO CLOUD TRENDS. KVWU IS REPORTING A SPRINKLE BUT THAT IS PRETTY ISOLATED. ELBOW LAKE ALSO HAS A LITTLE FOG BUT THINK THAT WILL BE SHORT LIVED. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 SURFACE TROUGH WILL CONTINUE TO PROPAGATE THROUGH THE FA. SCATTERED SHOWERS ACROSS THE EASTERN FA SHOULD BE EAST OF THE REGION BY 12Z. WEAK HIGH PRESSURE WILL MOVE INTO THE REGION. THE MAIN CHALLENGE FOR TODAY WILL BE CLOUDS AND ASSOCIATED TEMPERATURES. THERE IS AN AREA OF LOW CLOUDS BEHIND THE SURFACE TROUGH...ALONG THE INTERNATIONAL BORDER. THIS AREA OF CLOUDS HAS BEEN ADVECTING SOUTHWARD OVER THE PAST FEW HOURS...AND THE LATEST RAP GUIDANCE INDICATES THAT THIS TREND WILL CONTINUE. FOLLOWING THIS GUIDANCE MOST AREAS (EXCEPT PORTIONS OF SOUTHEAST NORTH DAKOTA) WILL LIKELY BE MOSTLY CLOUDY INTO AT LEAST THE EARLY AFTERNOON HOURS. THE THOUGHT IS THAT THE CLOUDS SHOULD BEGIN TO DISSIPATE ENOUGH BY MID-LATE AFTERNOON FOR MAX TEMPS TO BE ABLE TO REACH INTO THE MID-UPPER 70S. THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE TROUGH/COLD FRONT WILL MOVE THROUGH THE REGION TONIGHT INTO TUESDAY. FORCING AND INSTABILITY APPEAR TO BE STRONGER THAN THIS PAST SYSTEM...WHICH COULD LEAD TO MORE WIDESPREAD ACTIVITY. THE BEST SEVERE POTENTIAL WILL BE SOUTH OF THE FA WHERE INSTABILITY IS STRONGEST. HOWEVER...DEEP LAYER SHEAR WILL BE STRONG AND A FEW STRONGER STORMS WOULD SEEM POSSIBLE (ESPECIALLY TUESDAY AFTERNOON ACROSS SE ND INTO WC MN WHERE THE SFC FRONT WILL BE LOCATED DURING PEAK HEATING). .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 TUESDAY NIGHT-WEDNESDAY NIGHT...HIGH PRESSURE WILL AGAIN MOVE INTO THE REGION WHICH SHOULD LEAD TO MOSTLY DRY CONDITIONS. THURSDAY-SUNDAY NIGHT...00 UTC GFS/ECMWF SHOW SAME BASIC SYNOPTIC PATTERN...BUT DIFFER ON THE SPEED AT WHICH THE CLOSED CANADIAN LOW EJECTS INTO QUEBEC. THE ECMWF IS QUICKER THAN THE GFS AND THIS ALLOWS ANOTHER PACIFIC SHORT-WAVE TO MOVE INTO THE NORTHERN PLAINS NEXT WEEKEND. THE SLOWER GFS MAINTAINS DRY NORTHWEST FLOW ACROSS THE FORECAST AREA. GIVEN MODEL DIFFERENCES...WILL KEEP A MAINLY DRY FORECAST FRIDAY AND BEYOND. BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE THURSDAY AS ANOTHER COLD FRONT SWEEPS ACROSS THE REGION. COLD POOL ALOFT ASSOCIATED WITH DEEP CLOSED LOW WILL KEEP TEMPERATURES WELL BELOW MID-AUGUST NORMALS. HIGHS THURSDAY/ FRIDAY WILL STRUGGLE TO BREAK 70 DEGREES IN PLACES. A GRADUAL WARM-UP IS EXPECTED INTO THE WEEKEND...BUT STILL 5 TO 10 DEGREES COOLER THAN NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 658 AM CDT MON AUG 5 2013 IFR/MVFR CIGS WILL CONTINUE TO ADVECT EAST AND AFFECT MUCH OF THE REGION THIS MORNING...AND INTO THE AFTERNOON HOURS. CIGS WILL GRADUALLY LIFT THROUGH THE MORNING HOURS...BUT SHOULD REMAIN MVFR. THE MAIN CHALLENGE WILL BE WHEN/IF THESE CLOUDS CLEAR/DISSIPATE. USED THE LATEST RAP GUIDANCE FOR TIMING...WHICH HAS BEEN DOING A DECENT JOB WITH REALITY. THUNDER CHANCES INCREASE OVERNIGHT...LIKELY AFFECTING KDVL BY 12Z TUE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...GODON SHORT TERM...TG LONG TERM...TG/ROGERS AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
658 AM CDT MON AUG 5 2013 .UPDATE... ISSUED AT 658 AM CDT MON AUG 5 2013 WEAK SURFACE LOW LOCATED BETWEEN CROOKSTON AND FOSSTON IS PROPAGATING TO THE EAST...BUT SLOWER THAN ANTICIPATED. THIS FEATURE AND THE ASSOCIATED SURFACE TROUGH SHOULD BE JUST EAST OF THE FA BY 18Z. WILL ADD PATCHY DRIZZLE FOR THE NORTHERN VALLEY THIS MORNING. THERE IS SOME VALLEY INDUCED DRIZZLE WITH THE LOW LEVEL MOISTURE COMBINED WITH WEAK LIFT FROM THE NORTH WINDS ALONG THE VALLEY. OTHERWISE...LOWERED MAX TEMPS A COUPLE DEGREES AS CONFIDENCE HAS INCREASED THAT CLOUDS WILL REMAIN INTO THE AFTERNOON HOURS. HOWEVER...STILL THINK THAT CLOUDS WILL SCATTER BY MID-AFTERNOON TO ALLOW FOR HEATING INTO THE 70S (EXCEPT FOR MAYBE THE FAR EASTERN FA). && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 SURFACE TROUGH WILL CONTINUE TO PROPAGATE THROUGH THE FA. SCATTERED SHOWERS ACROSS THE EASTERN FA SHOULD BE EAST OF THE REGION BY 12Z. WEAK HIGH PRESSURE WILL MOVE INTO THE REGION. THE MAIN CHALLENGE FOR TODAY WILL BE CLOUDS AND ASSOCIATED TEMPERATURES. THERE IS AN AREA OF LOW CLOUDS BEHIND THE SURFACE TROUGH...ALONG THE INTERNATIONAL BORDER. THIS AREA OF CLOUDS HAS BEEN ADVECTING SOUTHWARD OVER THE PAST FEW HOURS...AND THE LATEST RAP GUIDANCE INDICATES THAT THIS TREND WILL CONTINUE. FOLLOWING THIS GUIDANCE MOST AREAS (EXCEPT PORTIONS OF SOUTHEAST NORTH DAKOTA) WILL LIKELY BE MOSTLY CLOUDY INTO AT LEAST THE EARLY AFTERNOON HOURS. THE THOUGHT IS THAT THE CLOUDS SHOULD BEGIN TO DISSIPATE ENOUGH BY MID-LATE AFTERNOON FOR MAX TEMPS TO BE ABLE TO REACH INTO THE MID-UPPER 70S. THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE TROUGH/COLD FRONT WILL MOVE THROUGH THE REGION TONIGHT INTO TUESDAY. FORCING AND INSTABILITY APPEAR TO BE STRONGER THAN THIS PAST SYSTEM...WHICH COULD LEAD TO MORE WIDESPREAD ACTIVITY. THE BEST SEVERE POTENTIAL WILL BE SOUTH OF THE FA WHERE INSTABILITY IS STRONGEST. HOWEVER...DEEP LAYER SHEAR WILL BE STRONG AND A FEW STRONGER STORMS WOULD SEEM POSSIBLE (ESPECIALLY TUESDAY AFTERNOON ACROSS SE ND INTO WC MN WHERE THE SFC FRONT WILL BE LOCATED DURING PEAK HEATING). .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 TUESDAY NIGHT-WEDNESDAY NIGHT...HIGH PRESSURE WILL AGAIN MOVE INTO THE REGION WHICH SHOULD LEAD TO MOSTLY DRY CONDITIONS. THURSDAY-SUNDAY NIGHT...00 UTC GFS/ECMWF SHOW SAME BASIC SYNOPTIC PATTERN...BUT DIFFER ON THE SPEED AT WHICH THE CLOSED CANADIAN LOW EJECTS INTO QUEBEC. THE ECMWF IS QUICKER THAN THE GFS AND THIS ALLOWS ANOTHER PACIFIC SHORT-WAVE TO MOVE INTO THE NORTHERN PLAINS NEXT WEEKEND. THE SLOWER GFS MAINTAINS DRY NORTHWEST FLOW ACROSS THE FORECAST AREA. GIVEN MODEL DIFFERENCES...WILL KEEP A MAINLY DRY FORECAST FRIDAY AND BEYOND. BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE THURSDAY AS ANOTHER COLD FRONT SWEEPS ACROSS THE REGION. COLD POOL ALOFT ASSOCIATED WITH DEEP CLOSED LOW WILL KEEP TEMPERATURES WELL BELOW MID-AUGUST NORMALS. HIGHS THURSDAY/ FRIDAY WILL STRUGGLE TO BREAK 70 DEGREES IN PLACES. A GRADUAL WARM-UP IS EXPECTED INTO THE WEEKEND...BUT STILL 5 TO 10 DEGREES COOLER THAN NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 658 AM CDT MON AUG 5 2013 IFR/MVFR CIGS WILL CONTINUE TO ADVECT EAST AND AFFECT MUCH OF THE REGION THIS MORNING...AND INTO THE AFTERNOON HOURS. CIGS WILL GRADUALLY LIFT THROUGH THE MORNING HOURS...BUT SHOULD REMAIN MVFR. THE MAIN CHALLENGE WILL BE WHEN/IF THESE CLOUDS CLEAR/DISSIPATE. USED THE LATEST RAP GUIDANCE FOR TIMING...WHICH HAS BEEN DOING A DECENT JOB WITH REALITY. THUNDER CHANCES INCREASE OVERNIGHT...LIKELY AFFECTING KDVL BY 12Z TUE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...TG LONG TERM...TG/ROGERS AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
348 AM CDT MON AUG 5 2013 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 SURFACE TROUGH WILL CONTINUE TO PROPAGATE THROUGH THE FA. SCATTERED SHOWERS ACROSS THE EASTERN FA SHOULD BE EAST OF THE REGION BY 12Z. WEAK HIGH PRESSURE WILL MOVE INTO THE REGION. THE MAIN CHALLENGE FOR TODAY WILL BE CLOUDS AND ASSOCIATED TEMPERATURES. THERE IS AN AREA OF LOW CLOUDS BEHIND THE SURFACE TROUGH...ALONG THE INTERNATIONAL BORDER. THIS AREA OF CLOUDS HAS BEEN ADVECTING SOUTHWARD OVER THE PAST FEW HOURS...AND THE LATEST RAP GUIDANCE INDICATES THAT THIS TREND WILL CONTINUE. FOLLOWING THIS GUIDANCE MOST AREAS (EXCEPT PORTIONS OF SOUTHEAST NORTH DAKOTA) WILL LIKELY BE MOSTLY CLOUDY INTO AT LEAST THE EARLY AFTERNOON HOURS. THE THOUGHT IS THAT THE CLOUDS SHOULD BEGIN TO DISSIPATE ENOUGH BY MID-LATE AFTERNOON FOR MAX TEMPS TO BE ABLE TO REACH INTO THE MID-UPPER 70S. THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE TROUGH/COLD FRONT WILL MOVE THROUGH THE REGION TONIGHT INTO TUESDAY. FORCING AND INSTABILITY APPEAR TO BE STRONGER THAN THIS PAST SYSTEM...WHICH COULD LEAD TO MORE WIDESPREAD ACTIVITY. THE BEST SEVERE POTENTIAL WILL BE SOUTH OF THE FA WHERE INSTABILITY IS STRONGEST. HOWEVER...DEEP LAYER SHEAR WILL BE STRONG AND A FEW STRONGER STORMS WOULD SEEM POSSIBLE (ESPECIALLY TUESDAY AFTERNOON ACROSS SE ND INTO WC MN WHERE THE SFC FRONT WILL BE LOCATED DURING PEAK HEATING). .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 348 AM CDT MON AUG 5 2013 TUESDAY NIGHT-WEDNESDAY NIGHT...HIGH PRESSURE WILL AGAIN MOVE INTO THE REGION WHICH SHOULD LEAD TO MOSTLY DRY CONDITIONS. THURSDAY-SUNDAY NIGHT...00 UTC GFS/ECMWF SHOW SAME BASIC SYNOPTIC PATTERN...BUT DIFFER ON THE SPEED AT WHICH THE CLOSED CANADIAN LOW EJECTS INTO QUEBEC. THE ECMWF IS QUICKER THAN THE GFS AND THIS ALLOWS ANOTHER PACIFIC SHORT-WAVE TO MOVE INTO THE NORTHERN PLAINS NEXT WEEKEND. THE SLOWER GFS MAINTAINS DRY NORTHWEST FLOW ACROSS THE FORECAST AREA. GIVEN MODEL DIFFERENCES...WILL KEEP A MAINLY DRY FORECAST FRIDAY AND BEYOND. BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE THURSDAY AS ANOTHER COLD FRONT SWEEPS ACROSS THE REGION. COLD POOL ALOFT ASSOCIATED WITH DEEP CLOSED LOW WILL KEEP TEMPERATURES WELL BELOW MID-AUGUST NORMALS. HIGHS THURSDAY/ FRIDAY WILL STRUGGLE TO BREAK 70 DEGREES IN PLACES. A GRADUAL WARM-UP IS EXPECTED INTO THE WEEKEND...BUT STILL 5 TO 10 DEGREES COOLER THAN NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1130 PM CDT SUN AUG 4 2013 THERE IS A BAND OF IFR/MVFR CIGS TO THE NORTH OF DEVILS LAKE...THAT COULD MOVE INTO THE NORTHERN AREAS OVERNIGHT INTO MONDAY MORNING WILL MENTION SOME MVFR CIGS IN THE NORTH...AND THIS WILL HAVE TO BE MONITORED TO SEE IF IFR CIGS DEVELOP. OTHERWISE...WINDS WILL SHIFT TO THE NW BEHIND THE SFC BOUNDARY BUT REMAIN AT OR UNDER 10 KT WITH A CLEARING TREND MONDAY AFTERNOON FROM NW TO SE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...TG LONG TERM...TG/ROGERS AVIATION...DK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1258 AM CDT MON AUG 5 2013 .UPDATE... ISSUED AT 1258 AM CDT MON AUG 5 2013 WEAK COLD FRONT EXTENDED FROM NEAR GRAND FORKS SOUTHWESTWARD TO NEAR BISMARCK AND DICKINSON. ISOLATED SHOWERS/THUNDERSTORMS HAD DISSIPATED AND HAVE SLIGHT CHANCES OF THUNDER DIMINISHING TO NO CHANCES BY AROUND 4 AM. THE MAIN CHANGE IN THIS UPDATE IS TO INCLUDE THE MENTION OF AREAS OF FOG FOR WESTERN AND CENTRAL NORTH DAKOTA. FOLLOWING THE WEAK FRONT...LOW CLOUDS WERE MOVING IN FROM THE NORTH AND ALSO FORMING/EXPANDING ACROSS NORTH CENTRAL NORTH DAKOTA. LATEST SAT PICS INDICATED SCATTERED LOW CLOUDS OR FOG ALONG THE FRONT...AND FOG WAS SEEN IN LOW LYING AREAS AROUND BISMARCK - THUS THINKING FOG AND LOW CLOUDS WILL DOMINATE MUCH OF THE OVERNIGHT HOURS. ONLY MINOR CHANGES IN OVERNIGHT LOWS. UPDATE ISSUED AT 917 PM CDT SUN AUG 4 2013 UPDATE FOR EVENING/OVERNIGHT POPS. STRONG THUNDERSTORMS ACROSS THE SOUTH CENTRAL HAVE CONTINUED TO TREND DOWNWARD OVER THE PAST HOUR AS THEY MOVE INTO A LESS UNSTABLE AIRMASS. THIS TREND IS EXPECTED TO CONTINUE THROUGH LATE EVENING. CAN`T RULE OUT AN ISOLATED STORM WITH SMALL HAIL...BUT NO ADDITIONAL SEVERE WEATHER IS EXPECTED. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 330 PM CDT SUN AUG 4 2013 MAIN FORECAST PROBLEM IN THE SHORT TERM PERIOD IS THE CHANCE OF SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON AND TONIGHT. MODELS HAVE BEEN HAVING A HARD TIME FIGURING OUT WHAT WILL TRANSPIRE LATE THIS AFTERNOON INTO THIS EVENING. MANY FAVORABLE FACTORS FOR CONVECTION ARE IN PLACE. STRONG UPPER LEVEL JET IS PROVIDING GOOD BULK SHEAR WITH INDIVIDUAL IMPULSES TRACKING ACROSS NORTHEAST MONTANA AND SOUTHERN SASKATCHEWAN. DEWPOINT HAVE CLIMBED INTO THE UPPER 50S TO LOWER 60S ACROSS THE AREA WITH AN INVERTED SURFACE TROUGH TRACKING SLOWLY EAST ACROSS WESTERN NORTH DAKOTA PROVIDING AN ADDITIONAL FOCUSING MECHANISM FOR CONVECTION. THE LIMITING FACTOR HAS BEEN THE EXTENSIVE CLOUD COVER PROVIDING MEAGER LOW LEVEL LAPSE RATES. 19Z KDIK LAPS SOUNDING STILL INDICATES AROUND 100 MB OF CIN TO BE OVERCOME. HOWEVER SKIES ARE BEGINNING TO CLEAR IN EASTERN MONTANA INTO WESTERN NORTH DAKOTA WITH A GOOD 3 HOURS OF HEATING BEFORE WE PASS OUR DIURNAL MAX AND CURRENTLY 1000-1500 J/KG OF CAPE AVAILABLE OVER FAR WESTERN NORTH DAKOTA. THE DIRECTIONAL SHEAR PROFILE DOES BECOME LESS FAVORABLE WITH SIGNIFICANT DRYING ALOFT TAKING PLACE BEHIND THE INVERTED TROUGH WHICH CURRENTLY LAYS OVER WESTERN NORTH DAKOTA. MESOSCALE MODELS HAVE BEEN ALL OVER THE PLACE WITH CONVECTION ACROSS WESTERN AND CENTRAL NORTH DAKOTA. ABOUT THE ONLY TREND THAT CAN BE SEEN IS THAT SUCCESSIVE RUNS HAVE BECOME LESS AND LESS OMINOUS FOR CONVECTION DEVELOPING OVER WESTERN OR CENTRAL NORTH DAKOTA THIS AFTERNOON OR THIS EVENING. WITH THIS SAID...STILL THINK THERE IS A WINDOW OF OPPORTUNITY FOR CONVECTION OVER CENTRAL NORTH DAKOTA LATE THIS AFTERNOON THROUGH LATE EVENING. THE 18Z RAP SHOWS CONVECTION TRYING TO DEVELOP OVER THE NORTH CENTRAL LATE THIS AFTERNOON...SPREADING SOUTHWEST INTO SOUTHWEST NORTH DAKOTA EARLY THIS EVENING. BUT THE STRONGEST CONVECTION REMAIN OVER THE NORTH CENTRAL INTO EASTERN NORTH DAKOTA...CLOSEST TO THE MID LEVEL SHORTWAVE TROUGH. THE 12Z WRF DID NOT HAVE A GOOD HANDLE ON CONVECTION ACROSS THE NORTH...BUT DOES DEVELOP A LINE OF CONVECTION ACROSS THE SOUTHWEST BETWEEN 21-22Z. EACH SUCCESSIVE RUN OF THE HRRR CONTINUES DEPICT WEAKER CONVECTION DEVELOPING OVER CENTRAL AND EASTERN NORTH DAKOTA THIS EVENING. SETTLED ON A 20-30 POPS OVER THE CENTRAL INTO THE SOUTHWEST LATE THIS AFTERNOON SPREADING INTO CENTRAL AND EASTERN NORTH DAKOTA TONIGHT. WILL NOT MENTION SEVERE WORDING BUT A FEW STRONG TO POSSIBLY SEVERE CELLS CAN NOT BE RULED OUT GIVEN THE STRONG SHEAR AND INCREASING CAPE. CONVECTION...IF IT DOES DEVELOP SHOULD MOVE OUT OF THE EASTERN CWA AFTER MIDNIGHT. WE THEN GET A PERIOD OF UPPER LEVEL RIDGING MONDAY AHEAD OF THE NEXT SHORTWAVE TROUGH...AND THE STRONG SHORTWAVE ASSOCIATED WITH THE RETROGRADING UPPER LEVEL LOW OVER DROPPING DOWN FROM THE HUDSON BAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 PM CDT SUN AUG 4 2013 THE NORTHERN PLAINS WILL BE UNDER NORTHWEST FLOW ALOFT MONDAY NIGHT WITH UPPER LEVEL RIDGING ACROSS THE SOUTHERN PLAINS AND DEEP LOW PRESSURE OVER THE WESTERN HUDSON BAY. WILL SEE INCREASING CHANCES OF SHOWERS/THUNDERSTORMS MONDAY EVENING WEST AND LATE MONDAY NIGHT THROUGH TUESDAY MORNING AREA WIDE AS A POTENT EMBEDDED S/WV ROTATES THROUGH THE FLOW AND INTO NORTH DAKOTA...IN ADDITION TO A SFC TROUGH/COLD FRONTAL BOUNDARY PUSHING SOUTH ACROSS THE STATE INTO TUESDAY MORNING. BY TUESDAY AFTERNOON...THE MAIN AREA OF SHOWERS/THUNDERSTORMS ASSOCIATED WITH THE COLD FRONT WILL HAVE MOVED SOUTH AND EAST OF CENTRAL NORTH DAKOTA. WILL NEED TO KEEP AN EYE ON THE SOUTHEAST DURING THE AFTERNOON FOR A STRONGER STORM WHERE MODELS PROJECT NEAR 1000 J/KG OF CAPE AND LITTLE IF ANY CIN. BY TUESDAY EVENING THE UPPER LEVEL LOW IS FORECAST TO BE BETWEEN HUDSON BAY AND LAKE WINNIPEG...MAINTAINING STRONG NORTHWEST FLOW ALOFT THROUGH THURSDAY (POSSIBLY INTO FRIDAY) WITH THE UPPER LOW REMAINING QUASI-STATIONARY. LINGERING LOW LEVEL MOISTURE COUPLED WITH EMBEDDED ENERGY IN THE FLOW ALOFT WILL MAINTAIN SOME CHANCE FOR DIURNALLY DRIVEN SHOWERS/ISOLATED THUNDERSTORMS BOTH WEDNESDAY AND THURSDAY. UPPER LOW PROPAGATES SLOWLY EAST TO OVER ONTARIO FRIDAY INTO FRIDAY NIGHT...WITH A RIDGE BUILDING INTO THE MONTANA ROCKIES. HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE DAKOTAS THURSDAY NIGHT...REMAINING IN PLACE WELL INTO THE WEEKEND. THIS WILL LEAD TO MAINLY DRY CONDITIONS AND CONTINUED BELOW NORMAL TEMPERATURES OVER MOST OF THE CWA THROUGH THE REMAINDER OF THE PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1258 AM CDT MON AUG 5 2013 LARGE AREA OF LOW CLOUDS AND FOG WAS FORMING/MOVING IN BEHIND A WEAK COLD FRONT THAT EXTENDED FROM NEAR KGFK TO NEAR KBIS AND KDIK AT 06Z. ADDED TEMPO GROUPS FOR MVFR/IFR CIGS AND VSBYS FOR TAF SITES. EXPECT DISSIPATING FOG AND LOWER CLOUDS BY AROUND 15Z/16Z IN KISN/KDIK/KMOT/KBIS AND BY AROUND 18Z AT KJMS. EXPECT SCATTERED THUNDERSTORMS IN WESTERN NORTH DAKOTA BY/AFTER 00Z AHEAD OF THE NEXT COLD FRONT THAT IS EXPECTED TO MOVE SOUTHEASTWARD ACROSS NORTH DAKOTA LATE MONDAY EVENING/NIGHT. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...TWH LONG TERM...NH AVIATION...JV
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
200 AM EDT MON AUG 5 2013 .SYNOPSIS... A BELT OF FAST WNW FLOW ALOFT WILL EXTEND FROM THE DAKOTAS TO THE MID-ATLANTIC COAST THROUGH THE MIDDLE OF THE WEEK...AS THE DEEP TROUGH OVER THE NORTHEAST SLIDES OFFSHORE AND PIVOTS AROUND A LARGE VORTEX MOVING SOUTHWEST FROM HUDSON BAY INTO SOUTH-CENTRAL CANADA. UPPER LEVEL HEIGHTS SHOULD RISE DURING THE SECOND HALF OF THE WEEK AS THE MID-LEVEL FLOW SHIFTS TO THE WEST-SOUTHWEST. AT THE SURFACE...HIGH PRESSURE OVER LK MICHIGAN THIS EVENING WILL MIGRATE OVER PENNSYLVANIA ON MONDAY BEFORE SLIDING OFF THE COAST MONDAY NIGHT. INCREASING MOISTURE IN ADVANCE OF A PLAINS/MIDWEST FRONTAL SYSTEM WILL BRING PERIODS RAIN FROM TUESDAY THROUGH THE END OF THE WEEK. BELOW NORMAL TEMPERATURES WILL MODERATE THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... STAGE IS SET FOR A VERY COOL NIGHT /FOR EARLY AUGUST/ ACROSS CENTRAL PA...AS NEGATIVE PWAT AND 8H TEMPS ANOMALIES ON THE ORDER OF -2SD WILL ACCOMPANY SFC HIGH BUILDING OVR THE STATE. KCLE RADAR LOOP EARLIER THIS EVENING SHOWED A FINE LINE PUSHING INTO NE OHIO AND NW PA. THIS BOUNDARY REPRESENTS A SFC TROF SEPARATING DRY AIR OVR CENTRAL PA FROM EVEN DRIER AIR PUSHING IN FROM THE NORTH. LATEST SFC-8H LYR DWPTS FROM NAM AND RAP PICK UP THIS FEATURE WELL AND SUGGEST THE BNDRY AND DRIEST AIR NEVER REACH THE LAUREL HIGHLANDS. THEREFORE...EXPECT THE NW MTNS TO SEE THE COOLEST TEMPS RELATIVE TO NORMAL WITH MINS DROPPING INTO THE U30S IN THE NORMALLY COLDER VALLEYS. ONLY POSSIBLE WILD CARD WILL BE CIRRUS SPREADING IN AHEAD OF FAST-MOVING SHORTWAVE OVR THE GRT LKS. CURRENT THINKING IS THAT THESE HIGH CLOUDS WILL BE THIN ENOUGH TO NOT SIGNIFICANTLY DAMPEN RADIATIONAL COOLING. HAVE LOWERED OVERNIGHT TEMPS TO ARND 40F OVR THE NW MTNS...TO THE M50S FROM MDT SOUTH AND EAST. A NEARLY CALM WIND...AND WATER TEMPS NEARLY 30F WARMER THAN ANTICIPATED AIR TEMPS...SHOULD RESULT IN A NEAR CERTAINTY OF FOG LATE TONIGHT IN THE DEEP RIVER/STREAM VALLEYS OF THE ALLEGHENIES...ESP NORTH OF I-80. PATCHY FOG ALSO LIKELY FURTHER EAST WITHIN THE RIDGE/VALLEY REGION FROM AOO TO UNV AND SEG...ESP NEAR ANY BODIES OF WATER. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... ANY PATCHY FOG WILL LIFT/DISSIPATE BETWEEN 13-15Z. THE FAIR/DRY WEATHER WILL PREVAIL TOMORROW WITH SFC HIGH PRESSURE IN CONTROL OF THE REGIONAL WEATHER PATTERN. HIGH QUALITY CANADIAN AIRMASS WILL FOSTER COMFORTABLE TEMPS AND HUMIDITY. A DECENT AMT OF SUNSHINE SHOULD EASILY ALLOW MIXING TO 850MB AND ENS MEAN 850 TEMPS ARND 10C SHOULD TRANSLATE TO MAX TEMPS IN THE 70S. AS THE SIGNIFICANT AREA OF COOL HIGH PRESSURE OVER PA SLIDES TO THE EAST LATE MONDAY INTO MONDAY NIGHT...A STG WAA PATTERN WILL EVOLVE EWD FROM THE OH VLY. THIS IS SHOWN NICELY BY A BROAD SURGE OF POSITIVE 850-700MB THETA-E ADVECTION. DEVELOPING SLY FLOW AHEAD OF APPROACHING WARM FRONT WILL AID IN INCREASING LLVL MSTR...AND 90KT JET EMBEDDED WITHIN BELT OF FAST WNW FLOW ALOFT WILL PROVIDE SYNOPTIC LIFT. CONSENSUS OF OPRN MDLS AND ENS GUIDANCE SUPPORTS CHC FOR SHOWERS ACRS THE SW 1/2 OF THE CWA IN THE 06-12Z TUE TIMEFRAME. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... WEAK TO MODERATE WSWRLY FLOW ALOFT AT THE START OF THE PERIOD WILL TURN MORE NWRLY AS HUDSON BAY UPPER LOW PROGRESSES INTO EASTERN CANADA BY THE END OF THE PERIOD. PLENTY OF WEAK SHORTWAVE TROFS WILL BE PRESENT TO BRING WEAK FRONTS THROUGH THE REGION DURING THE PERIOD. A STG WAA PATTERN WILL EVOLVE EWD FROM THE OH VLY. THIS IS SHOWN NICELY BY A BROAD SURGE OF POSITIVE 850-700MB THETA-E ADVECTION. DEVELOPING SOUTHERLY FLOW AHEAD OF APPROACHING WARM FRONT WILL AID IN INCREASING LLVL MSTR...AND 90KT JET EMBEDDED WITHIN BELT OF FAST WNW FLOW ALOFT WILL PROVIDE SYNOPTIC LIFT. CONSENSUS OF 04/12Z OPRN MDLS AND ENS GUIDANCE SUPPORTS CHC FOR SHOWERS ACRS THE SW 1/2 OF THE CWA IN THE 00-12Z TUE TIMEFRAME UPPER RIDGE OVER NUNAVUT/NW TERRITORIES WILL MAINTAIN MEAN TROUGHING OVER SERN CANADA...ANCHORED BY A CLOSED LOW TRACKING EWD ACRS MANITOBA/ONTARIO INTO QUEBEC BY THE END OF THE PERIOD. MODEL SPREAD IN THE TIMING OF THE LOW IS IMPACTING SFC/PCPN DETAILS DOWNSTREAM. SHORTWAVE ENERGY ROTATING AROUND THE BASE OF THE CLOSED LOW WILL PROPEL A SFC FRONT FROM THE NRN PLAINS SEWD THRU THE MIDWEST/OH VLY TUE-WED BEFORE SLOWING ITS PROGRESSION OVER THE APPLCHNS AND MID-ATLC STATES THU-FRI. WAVES OF LOW PRES RIDING ALONG THE FRONT WILL BE ACCOMPANIED BY RNFL OF VARYING INTENSITY WED-FRI...WITH SCT CONVECTION PRECEDING A WARM FRONT ON TUE. THE OVERALL PATTERN LOOKS PERIODICALLY WET AND UNSETTLED...WITH SEVERAL BOUTS OF SHOWERS/TSTMS TUE-FRI. SOME MODERATION IN DAILY TEMPS SHOULD OCCUR AHEAD OF THE FRONT. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE PROVIDING WHAT SHOULD BE A GOOD RADIATIONAL COOLING NIGHT. EXPECT SOME FOG FORMATION OVERNIGHT...BUT A PERSISTENT LIGHT NORTHWEST WIND...COMBINED WITH SOME HIGH CLOUDS...MAY LIMIT FOG EXTENT. AFTER MORNING FOG...LOOK FOR HIGH PRESSURE TO PROVIDE VFR CONDITIONS MONDAY. WARM ADVECTION WILL INTRODUCE LOW CHANCE SHRA/TSRA BEGINNING MONDAY NIGHT INTO TUESDAY....WITH GREATER CHANCES WEDNESDAY AS WARM FRONT MOVES ACROSS THE REGION. APPROACHING COLD FRONT WILL THEN TRIGGER POSSIBLE SHRA/TSRA LATER THURSDAY...MAINLY IN THE NORTHWEST. MORE WIDESPREAD ACTIVITY FRIDAY WITH COLD FRONTAL PASSAGE. OUTLOOK... TUE-WED...MAINLY VFR...BUT A CHC OF SHOWERS AND STORMS. THU-FRI...GENERALLY VFR...BUT RESTRICTIONS IN SHRA/TSRA. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...FITZGERALD SHORT TERM...CERU/STEINBUGL LONG TERM...GARTNER/STEINBUGL AVIATION...JUNG/MARTIN
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.

NOT ANTICIPATING ANY MAJOR CHANGES TNT. DID LOWER POPS SOME FOR THE WESTERN CWA WHERE IT APPEARS ANY CONVECTION IS HAVING A HARD TIME GETTING ITS ACT TOGETHER OVER THE WESTERN HIGH PLAINS. FOR THE NORTHEAST CWA WILL MAINTAIN DECENT CHC POPS. NICE LOOKING S/W IN WV IMAGERY OVER WESTERN NORTH DAKOTA IS HELPING PROVIDE THE LIFT FOR SOME STORMS SOUTH OF BISMARCK. SOME OF THAT ACTIVITY MAY MAKE ITS WAY DOWN INTO NORTHERN SOUTH DAKOTA THIS EVENING. ONLY PROBLEM IS THAT ITS STILL FAIRLY STABLE OVER THE NORTHEAST PART OF THE CWA PER THE 00Z RAOB. MEANWHILE THE HRRR CONTINUES TO DEVELOP ELEVATED OVERNIGHT STUFF ON THE NOSE OF THE LLJ AHEAD OF THAT PREVIOUSLY MENTIONED S/W...SO WILL LEAVE POPS AS IS DESPITE SOME CONCERNS ABOUT TOO MUCH STABILITY OVER THE EASTERN CWA. TEMPS LOOK OKAY. && .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT A WEALTH OF CLOUDS COVER THE CWA THIS AFTERNOON...MUCH OF IT MVFR ACROSS CENTRAL SD. THE SUMMER SUN HAS NOT BURNED THIS OFF AND VIS SATELLITE INDICATES IT IS STILL STUBBORN TO LEAVE AND RATHER THICK. LOOKS LIKE SKIES WILL STAY MOSTLY CLOUDY THROUGH THE AFTERNOON. WITH THE ABUNDANCE OF CLOUDS...THE ATMOSPHERE HAS NOT BEEN ALLOWED TO DESTABILIZE. THE ONLY AREA THAT HAS RECEIVED A GOOD AMOUNT OF SUN TODAY IS FAR WESTERN SD. MESOANALYSIS SHOWS THIS AREA IS PUSHING 2000 J/KG MLCAPE WITH 50 KNOTS 0-6KM SHEAR. FARTHER EAST TOWARDS THE MISSOURI VALLEY...ONLY ABOUT 500 J/KG MLCAPE AND A LARGE CAP STILL IN PLACE. SPC SLIGHT RISK THREAT STILL HIGHLIGHTS WESTERN SD AND THIS LOOKS GOOD BASED ON CURRENT SITUATION. THE CWA HAS BEEN QUIET ALL DAY LONG AND HAD TO CUT POPS BACK TO SLIGHT CHANCE THEN EVENTUALLY TO NOTHING THROUGHOUT THE DAY. RATHER DIFFICULT PRECIP FORECAST TONIGHT AS WELL AND HI RES MODELS NOT OFFERING UP MUCH HELP. IT APPEARS THERE MAY BE TWO AREAS OF FOCUS...WITH THE POSSIBILITY OF A LARGE PORTION OF THE CWA FALLING IN BETWEEN THE TWO BEST AREAS OF PRECIP POTENTIAL. THE FIRST AREA IS THE AREA OF WESTERN SD. WHATEVER FIRES LATER THIS AFTERNOON AND EVENING COULD BECOME STRONG TO SEVERE AND EVENTUALLY MAKE ITS WAY INTO THE FAR WESTERN COUNTIES BY THIS EVENING. BUT ANYTHING THAT MOVES EAST WILL ENCOUNTER MUCH MORE STABLE AIR. THE NEXT AREA TO WATCH IS THE FAR NORTHEAST CWA LATER THIS EVENING AND OVERNIGHT. WATER VAPOR IMAGERY SHOWS TWO SEPARATE WAVES OF ENERGY ACROSS MONTANA AND FAR SOUTHERN CANADA. THESE WAVES WILL SLIDE EAST-SOUTHEAST INTO THE REGION OVERNIGHT AND MODELS ARE SHOWING SHOWERS AND STORMS ACROSS EASTERN ND...FAR NORTHEAST SD AND INTO MN THIS EVENING AND OVERNIGHT. MUCAPE INCREASES TO 1000-1500 J/KG WITH BULK SHEAR OF AROUND 50 KNOTS. THERE COULD BE A FEW STRONGER STORMS WITHIN THE WAA REGIME ACROSS THE FAR NORTHEAST CWA LATER TONIGHT. TRIED TO CONSTRUCT POP GRIDS WITH HIGHER CHANCES ACROSS THE FAR NORTHEAST AND FAR SOUTHWEST...BUT CONFIDENCE THIS GO AROUND IS RATHER LOW. AFTER QUIET CONDITIONS ON MONDAY...WILL THEN BE WATCHING THE COLD FRONTAL PASSAGE ON TUESDAY. FAIRLY POTENT FRONT MOVING THROUGH DURING THE DAY AND CHANCES FOR SHOWERS AND STORMS LOOK PRETTY GOOD. THERE COULD BE A FEW STRONGER STORMS ON TUESDAY WITH 1000-1500 J/KG GENERALLY SPEAKING AND 50+ KNOTS OF SHEAR. ALTHOUGH...STRONGEST INSTABILITY IS SOUTH OF THE REGION. .LONG TERM...WEDNESDAY THROUGH SUNDAY BELOW NORMAL TEMPERATURES WILL CONTINUE TO RULE THE LONG TERM PERIOD. A STRONG SOUTHERN CANADIAN COLD VORTEX WILL WOBBLE SLOWLY EAST THROUGH THE END OF THE WEEK AND INTO THE WEEKEND. THIS WILL PUT US IN CONTINUED COOL NORTHWEST FLOW. THIS FLOW WILL BECOME MORE WEST NORTHWEST THROUGH THE WEEKEND AS AN UPPER LEVEL RIDGE AXIS PUSHES IN FROM THE WEST. THE MODELS SHOW SURFACE CANADIAN HIGH PRESSURE DOMINATING THROUGH MOST OF THE LONG TERM. A COLD FRONT COMING ACROSS THE CWA FOR WEDNESDAY NIGHT AND THURSDAY WILL BRING CHANCES OF SHOWERS AND THUNDERSTORMS TO THE ENTIRE CWA. OTHERWISE...THE SHOWER/STORM CHANCES WILL BE CONFINED TO ALONG AND WEST OF THE MISSOURI RIVER FOR MOST OF THE REST OF THE LONG TERM AS SHORT WAVES COME OVER THE WESTERN RIDGE. AREAS MAINLY EAST OF THE MISSOURI RIVER SHOULD REMAIN MORE ON THE STABLE AND DRIER SIDE. ALSO WITH THE SURFACE HIGH PRESSURE...DONT EXPECT MUCH FOR WIND THROUGH THE ENTIRE LONG TERM. HIGHS THROUGH THE ENTIRE LONG TERM SHOULD BE MOSTLY IN THE 70S TO THE LOWER 80S ACROSS THE CWA. && .AVIATION... 06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS MVFR CIGS ARE EXPECTED FOR A COUPLE MORE HOURS TONIGHT AT KABR/KATY. OTHERWISE...VFR FLYING WEATHER CONDITIONS WILL PREVAIL. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...TDK/DORN SHORT TERM...TMT LONG TERM...MOHR AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1021 PM CDT TUE AUG 6 2013 .UPDATE...RADAR CURRENTLY SHOWING WIDELY SCATTERED LIGHT SHOWERS ACROSS MIDDLE TENNESSEE, WITH VERY HUMID AIR MASS IN PLACE. EVENING SOUNDING FROM OHX SHOWS PRECIPITABLE WATER OF 2.11 INCHES AND A K-INDEX OF 33. LIFTED INDEX REMAINS -5.6, WITH CONVECTIVE AVAILABLE POTENTIAL ENERGY OF 2,528 J/KG, SO THERE`S PLENTY OF INSTABILITY AROUND, TOO. LATEST HRRR SHOWS SCATTERED ACTIVITY CONTINUING THROUGH THE NIGHT ACROSS MIDDLE TENNESSEE, BUT NOTHING TOO HEAVY. EARLIER DROPPED EVENING POP`S FROM LIKELY TO SCATTERED, LEAVING OVERNIGHT POP`S ALONE. GOING TO GO AHEAD AND REDUCE OVERNIGHT POP`S TO SCATTERED, TOO, AS THERE`S NOTHING TO SUGGEST MUCH OF AN INCREASE IN ACTIVITY BETWEEN 06Z AND 12Z. && .PREV DISCUSSION... /ISSUED 701 PM CDT TUE AUG 6 2013/ UPDATE...CUTTING EVENING POP`S BACK TO SCATTERED GIVEN THE LACK OF COVERAGE NOW AND THE LACK OF CONVECTIVE DEVELOPMENT FORECAST BY THE HRRR THROUGH 06Z. LEAVING OVERNIGHT POP`S UNCHANGED. PREV DISCUSSION... /ISSUED 636 PM CDT TUE AUG 6 2013/ UPDATE...FOR 00Z TAFS. AVIATION... AN UPPER LEVEL DISTURBANCE OVER WESTERN KY IS TRACKING ESE ACROSS THE REGION. THIS WILL CONTINUE A CHANCE FOR OFF AND ON SHRA/TSRA MAINLY IN A PERFECT LINE WITH OUR TERMINALS...FROM CKV TO BNA TO CSV...OVER THE NEXT FEW HOURS. ONCE THE DISTURBANCE MOVES EAST...SKIES SHOULD GO FROM BKN-OVC TO MORE FEW-SCT. HOWEVER TOWARDS DAWN...A WARM FRONTAL BOUNDARY SOUTHWEST OF THE REGION WILL PUSH NNE. VSBYS AHEAD OF THIS FEATURE COULD DROP GIVEN THE AMOUNT OF LOW-LEVEL MOISTURE AND THUS WE CONTINUE THE MVFR VSBYS AROUND DAWN (IFR AT CSV WITH MVFR CIGS). CHANCES FOR SHRA/TSRA TOMORROW MORNING COULD BE ELEVATED IF A CONVECTIVE COMPLEX CAN GET GOING OUT OVER THE PLAINS AND TRACK SOUTHEAST ALONG THE WARM FRONT...WHICH SHOULD AFFECT OUR TAF SITES SHOULD IT HOLD TOGETHER. OTHERWISE...A SCATTERED SHRA/TSRA CHANCE WILL BE THE RULE FOR MUCH OF WEDNESDAY. CAN HANDLE BETTER TIMING WITH TEMPOS/PREVAILING GROUPS WITH LATER FORECASTS. PREV DISCUSSION... /ISSUED 324 PM CDT TUE AUG 6 2013/ DISCUSSION...UNSETTLED AND SOMEWHAT UNUSUAL AUGUST WX WILL CONTINUE INTO THIS FORECAST PERIOD WITH INTERMITTENT SHOWERS AND THUNDERSTORMS. OUR MAIN CONCERN THROUGH THE NEXT COUPLE OF DAYS IS LOCALLY HEAVY RAINFALL. SO FAR...OUR COVERAGE AREA HAS NOT RECEIVED CONCENTRATED HEAVY RAINFALL AMOUNTS...SO WE DO NOT NEED ANY FLASH FLOOD WATCHES AT THIS TIME. VERY MOIST AIR HAS BEEN MOVING INTO MID TN...AND DEEP MOISTURE WILL REMAIN IN PLACE THROUGH AT LEAST THE NEXT 48 HOURS. FORECAST SOUNDINGS SHOW PRECIPITABLE WATER VALUES CLIMBING WELL OVER 2 INCHES AT TIMES. LIFT ACROSS A WARM FRONTAL ZONE WILL PERSIST THROUGH TONIGHT INTO WEDNESDAY MORNING AS ANOTHER UPPER WAVE APPROACHES FROM THE WEST. ADDITIONAL IMPULSES AND RESIDUAL BOUNDARIES WILL BE THE MAIN FACTORS TOMORROW AFTERNOON THROUGH THURSDAY. ALL OF THIS MEANS A GOOD CHANCE FOR MORE RAIN AND THUNDERSTORMS. UNFORTUNATELY...THERE ARE MANY UNCERTAINTIES REGARDING THE EXACT TIMING AND EVOLUTION OF THE SHOWERS AND STORMS...SO ANYONE WITH OUTDOOR PLANS WILL NEED TO KEEP A CLOSE WATCH ON RADAR LOOPS AND SHORT RANGE FORECAST UPDATES. IN GENERAL...1 TO 2 INCHES OF RAIN CAN BE EXPECTED THROUGH THE NEXT COUPLE OF DAYS...BUT THE STRONGER STORMS WILL EASILY PRODUCE LOCALIZED HEAVIER AMOUNTS...WITH RAINFALL RATES WELL OVER AN INCH PER HOUR POSSIBLE. A FEW STRONG STORMS WITH GUSTY WINDS ARE POSSIBLE TONIGHT. TOMORROW AFTERNOON AND THURSDAY AFTERNOON LOOK LIKE THE MOST UNSTABLE TIMES...WHEN A FEW SEVERE STORMS COULD DEVELOP. THESE WOULD PRODUCE LOCALIZED STRONG WIND GUSTS...HEAVY DOWNPOURS AND FREQUENT LIGHTNING. WE DO NOT SEE ANY WIDESPREAD OR WELL ORGANIZED SEVERE WX THREAT AT THIS TIME. BY FRIDAY AND CONTINUING INTO SATURDAY...RISING HEIGHTS WILL DEVELOP WITH A BERMUDA RIDGE BRIDGING ACROSS TO A SOUTHERN PLAINS RIDGE. THIS PATTERN WILL BRING VERY WARM AND HUMID CONDITIONS WITH SCATTERED DIURNALLY DRIVEN THUNDERSTORMS. MODELS INDICATE A FRONT DROPPING TOWARD THE AREA SATURDAY NIGHT INTO SUNDAY. SOME SLIGHTLY DRIER AIR MAY SEEP IN FROM THE NORTH...BUT WITH THE FRONT STALLING OVER THE AREA...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE. LOOKING AHEAD INTO NEXT WEEK...MORE OF THE SAME UNSETTLED SUMMER PATTERN OF 2013...AS NORTHWEST FLOW ALOFT BRINGS PERIODIC DISTURBANCES ACROSS THE REGION. 13 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ROSE
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
701 PM CDT TUE AUG 6 2013 .UPDATE...CUTTING EVENING POP`S BACK TO SCATTERED GIVEN THE LACK OF COVERAGE NOW AND THE LACK OF CONVECTIVE DEVELOPMENT FORECAST BY THE HRRR THROUGH 06Z. LEAVING OVERNIGHT POP`S UNCHANGED. && .PREV DISCUSSION... /ISSUED 636 PM CDT TUE AUG 6 2013/ UPDATE...FOR 00Z TAFS. AVIATION... AN UPPER LEVEL DISTURBANCE OVER WESTERN KY IS TRACKING ESE ACROSS THE REGION. THIS WILL CONTINUE A CHANCE FOR OFF AND ON SHRA/TSRA MAINLY IN A PERFECT LINE WITH OUR TERMINALS...FROM CKV TO BNA TO CSV...OVER THE NEXT FEW HOURS. ONCE THE DISTURBANCE MOVES EAST...SKIES SHOULD GO FROM BKN-OVC TO MORE FEW-SCT. HOWEVER TOWARDS DAWN...A WARM FRONTAL BOUNDARY SOUTHWEST OF THE REGION WILL PUSH NNE. VSBYS AHEAD OF THIS FEATURE COULD DROP GIVEN THE AMOUNT OF LOW-LEVEL MOISTURE AND THUS WE CONTINUE THE MVFR VSBYS AROUND DAWN (IFR AT CSV WITH MVFR CIGS). CHANCES FOR SHRA/TSRA TOMORROW MORNING COULD BE ELEVATED IF A CONVECTIVE COMPLEX CAN GET GOING OUT OVER THE PLAINS AND TRACK SOUTHEAST ALONG THE WARM FRONT...WHICH SHOULD AFFECT OUR TAF SITES SHOULD IT HOLD TOGETHER. OTHERWISE...A SCATTERED SHRA/TSRA CHANCE WILL BE THE RULE FOR MUCH OF WEDNESDAY. CAN HANDLE BETTER TIMING WITH TEMPOS/PREVAILING GROUPS WITH LATER FORECASTS. PREV DISCUSSION... /ISSUED 324 PM CDT TUE AUG 6 2013/ DISCUSSION...UNSETTLED AND SOMEWHAT UNUSUAL AUGUST WX WILL CONTINUE INTO THIS FORECAST PERIOD WITH INTERMITTENT SHOWERS AND THUNDERSTORMS. OUR MAIN CONCERN THROUGH THE NEXT COUPLE OF DAYS IS LOCALLY HEAVY RAINFALL. SO FAR...OUR COVERAGE AREA HAS NOT RECEIVED CONCENTRATED HEAVY RAINFALL AMOUNTS...SO WE DO NOT NEED ANY FLASH FLOOD WATCHES AT THIS TIME. VERY MOIST AIR HAS BEEN MOVING INTO MID TN...AND DEEP MOISTURE WILL REMAIN IN PLACE THROUGH AT LEAST THE NEXT 48 HOURS. FORECAST SOUNDINGS SHOW PRECIPITABLE WATER VALUES CLIMBING WELL OVER 2 INCHES AT TIMES. LIFT ACROSS A WARM FRONTAL ZONE WILL PERSIST THROUGH TONIGHT INTO WEDNESDAY MORNING AS ANOTHER UPPER WAVE APPROACHES FROM THE WEST. ADDITIONAL IMPULSES AND RESIDUAL BOUNDARIES WILL BE THE MAIN FACTORS TOMORROW AFTERNOON THROUGH THURSDAY. ALL OF THIS MEANS A GOOD CHANCE FOR MORE RAIN AND THUNDERSTORMS. UNFORTUNATELY...THERE ARE MANY UNCERTAINTIES REGARDING THE EXACT TIMING AND EVOLUTION OF THE SHOWERS AND STORMS...SO ANYONE WITH OUTDOOR PLANS WILL NEED TO KEEP A CLOSE WATCH ON RADAR LOOPS AND SHORT RANGE FORECAST UPDATES. IN GENERAL...1 TO 2 INCHES OF RAIN CAN BE EXPECTED THROUGH THE NEXT COUPLE OF DAYS...BUT THE STRONGER STORMS WILL EASILY PRODUCE LOCALIZED HEAVIER AMOUNTS...WITH RAINFALL RATES WELL OVER AN INCH PER HOUR POSSIBLE. A FEW STRONG STORMS WITH GUSTY WINDS ARE POSSIBLE TONIGHT. TOMORROW AFTERNOON AND THURSDAY AFTERNOON LOOK LIKE THE MOST UNSTABLE TIMES...WHEN A FEW SEVERE STORMS COULD DEVELOP. THESE WOULD PRODUCE LOCALIZED STRONG WIND GUSTS...HEAVY DOWNPOURS AND FREQUENT LIGHTNING. WE DO NOT SEE ANY WIDESPREAD OR WELL ORGANIZED SEVERE WX THREAT AT THIS TIME. BY FRIDAY AND CONTINUING INTO SATURDAY...RISING HEIGHTS WILL DEVELOP WITH A BERMUDA RIDGE BRIDGING ACROSS TO A SOUTHERN PLAINS RIDGE. THIS PATTERN WILL BRING VERY WARM AND HUMID CONDITIONS WITH SCATTERED DIURNALLY DRIVEN THUNDERSTORMS. MODELS INDICATE A FRONT DROPPING TOWARD THE AREA SATURDAY NIGHT INTO SUNDAY. SOME SLIGHTLY DRIER AIR MAY SEEP IN FROM THE NORTH...BUT WITH THE FRONT STALLING OVER THE AREA...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE. LOOKING AHEAD INTO NEXT WEEK...MORE OF THE SAME UNSETTLED SUMMER PATTERN OF 2013...AS NORTHWEST FLOW ALOFT BRINGS PERIODIC DISTURBANCES ACROSS THE REGION. 13 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ROSE
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AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
853 PM CDT TUE AUG 6 2013 .UPDATE... THUNDERSTORMS ACROSS EAST CENTRAL MN AND NORTHWEST WISCONSIN ARE TRYING TO ORGANIZE INTO A LARGER LINE COMPLEX. THE BEST AXIS OF MOISTURE AND INSTABILITY LOOKS TO BE OVER WESTERN WISCONSIN...INTO SOUTHERN WISCONSIN. DEVELOPMENT ON THE SOUTHWEST FLANK HAS STRUGGLED TO EXPAND FARTHER SOUTHWEST. THE HRRR HAS BEEN VERY CONSISTENT WITH ITS HOURLY UPDATES IN BRINGING A LINE OF STORMS THROUGH HERE BETWEEN ABOUT 1 AND 4 AM...HITTING MOST OF THE FORECAST AREA. THE STORMS COULD BE WEAKENING BY THE TIME THEY REACH THE SOUTHEAST...BUT IF THIS THING GETS BETTER ORGANIZED WITH GOOD COLD POOL DYNAMICS...IT WILL LIVE ON LONGER. THE MAIN THREAT WILL BE STRONG STRAIGHT LINE WINDS AND LARGE HAIL. CURRENT TIMING HAS IT ENTERING MARQUETTE...GREEN LAKE...SAUK COUNTIES BETWEEN MIDNIGHT AND 1 AM...EXITING THE SOUTHEAST BY AROUND 4 AM. THE LINE SHOULD BEGIN TO ACCELERATE ONCE IT BECOMES BETTER ORGANIZED...SO CURRENT MOVEMENT ISN/T AN ACCURATE EXTRAPOLATION. && .AVIATION/06Z TAFS/... VFR CONDITIONS ARE GENERALLY EXPECTED THROUGH THE PERIOD. A LINE OF STRONG THUNDERSTORMS WILL MOVE THROUGH THE AREA BETWEEN MIDNIGHT AND 4 AM. THEY SHOULD REACH MADISON BY 2 AM AND MILWAUKEE/KENOSHA AROUND 4 AM. BRIEF MVFR CONDITIONS ARE LIKELY WITH THE THUNDERSTORMS...ALONG WITH STRONG AND GUSTY NORTHWEST WINDS FROM THE STORMS. PRESSURE GRADIENT WINDS WILL BE SOUTHWEST UNTIL FRONTAL PASSAGE EARLY WEDNESDAY AFTERNOON. && .PREV DISCUSSION... /ISSUED 345 PM CDT TUE AUG 6 2013/ VERY SHORT TERM...TONIGHT AND WEDNESDAY. IT SHOULD BE STAY DRY THROUGH EARLY EVENING...WITH SHOWERS/STORMS FOCUSING WEST CLOSER TO AN APPROACHING COLD FRONT. AS THE FRONT APPROACHES...THE ACTIVITY WILL LIKELY MOVE INTO THE FORECAST AREA LATE EVENING INTO TONIGHT. CURRENT THINKING IS THAT THE BEST CHANCE FOR STORMS WILL BE FROM 10 PM TO 4 AM. THE BIG QUESTIONS REMAIN HOW MUCH OF THE CONVECTION WILL SURVIVE AND IF ANY STORMS WILL BE SEVERE. STILL LOOKS LIKE THERE COULD BE A GOOD AMOUNT OF INSTABILITY AFTER SUNSET. LATEST SOUNDINGS ARE MORE REASONABLE WITH DEWPOINTS AND ARE INDICATING UPWARDS OF 1000 J/KG CAPE AS THE FRONT APPROACHES. 0-6 KM BULK SHEAR WILL BE IN THE 35-45 KT RANGE...PLENTY TO CONSIDER STRONG TO SEVERE STORMS. THE LATEST UPDATE OF THE SPC DAY 1 CONVECTIVE OUTLOOK PULLED THE SLIGHT RISK OUT OF THE EAST...BUT KEPT IT FOR THE WESTERN TWO THIRDS OF THE FORECAST AREA. THE MAIN THREAT WOULD PROBABLY BE DAMAGING WINDS WITH BOWING LINES. WILL HAVE TO MONITOR UPSTREAM ACTIVITY THIS AFTERNOON AND EVENING TO CONTINUE TO ASSESS STORM TIMING AND THE SEVERE THREAT FOR SOUTHERN WISCONSIN. EXPECTING MAINLY DRY WEATHER BY DAYBREAK WEDNESDAY...WITH A SHOWER OR STORM POSSIBLY LINGERING INTO EARLY MORNING. IT WILL BE DRY MID MORNING THROUGH THE AFTERNOON BEHIND THE DEPARTING FRONT. LOOKS LIKE WARM AIRMASS WILL LINGER LONG ENOUGH FOR NEAR NORMAL TEMPS TOMORROW. SHOULD BE A PRETTY NICE DAY. SHORT TERM...WEDNESDAY NIGHT THROUGH FRIDAY. DRIER AIR AND WEAK HIGH PRESSURE SETTLES IN BEHIND EXITING CDFNT AND LINGERS THROUGH THURSDAY. TEMPERATURES WILL REMAIN AVERAGING A LITTLE BELOW NORMAL FOR EARLY AUGUST. SHORT TERM GUIDANCE IS IN REASONABLE AGREEMENT ON CARRYING WEAK CDFNT THRU SRN WI THURSDAY NIGHT. LOW PRESSURE MOVING ACROSS SRN CANADA A BIT MORE AMPLIFIED THAN DEPICTED BY EARLIER GUIDANCE...HOWEVER MOISTURE REMAINS LIMITED. FOR NOW WL ADD SMALL POPS FOR -SHRA ACROSS NRN CWA LATER THU NIGHT AS LITTLE INSTABILITY SEEN ON FORECAST SOUNDINGS AT THIS TIME. SLIGHTLY MORE ZONAL FLOW ON FRIDAY BUT STILL EXPECT ANY PRECIPITATION THAT DEVELOPS NORTH OF STRONG FRONTAL BOUNDARY TO THE SOUTH SHOULD REMAIN SOUTH OF THE AREA. HOWEVER MAY SEE SOME HIGH CLOUDS AFFECT SRN WI ON FRIDAY. LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. MEDIUM RANGE GUIDANCE HAVING SOME DIFFICULTY IN STRENGTH AND EASTWARD TIMING OF DEEP VORTEX NORTH OF THE GREAT LAKES AT THE START OF THE PERIOD. ECMWF AND GEM SHOWING LESS WEST-NORTHWEST FLOW IN ITS WAKE ACROSS SOUTHERN WI...AND MORE ZONAL FLOW...WHILE GFS HAS TRENDED BACK TO OLDER ECMWF SOLUTIONS. THE MORE ZONAL FLOW OVER THE UPPER MIDWEST AND CENTRAL MS VALLEY REGION WILL ALLOW PRECIP AND CLOUDS FORMING ALONG AND NORTH OF STRONG EAST-WEST FRONTAL BOUNDARY TO INCH CLOSER TO SRN WI. HWVR AT THIS TIME STILL APPEARS DRIER ZONAL FLOW AND SLOW-MOVING WEAK HIGH PRESSURE SHOULD CONTINUE TO BRING DRY WEATHER TO SRN WI FOR THE WEEKEND. UPSTREAM RIDGING ARCING FROM THE SOUTHERN PLAINS ACROSS THE ROCKIES LOOKS TO REMAIN NEARLY STATIONARY INTO EARLY NEXT WEEK. SOME CONSISTENCY IN MEDIUM RANGE GUIDANCE BRINGING SHORT WAVE TROUGH FROM SOUTHERN CANADA ACROSS WI SUN NGT/MON TIME FRAME. SLIGHT INCREASE IN MID-LEVEL MOISTURE AT THIS TIME PER TIME-SECTIONS SO WL CONTINUE SMALL POPS. DRY CONDITIONS RETURN FOR EARLY NEXT WEEK. GFS 5 DAY 5H MEANS CONTINUE TO SHOW HEIGHTS REMAINING SLIGHTLY BELOW NORMAL FOR THE PERIOD...CONTRIBUTING TO DAYTIME TEMPERATURES CONTINUING TO AVERAGE SLIGHTLY BELOW NORMAL. AVIATION /00Z TAFS/...STILL LOOKS LIKE THERE WILL BE SHOWERS/STORMS THIS EVENING AND INTO TONIGHT AS A COLD FRONT APPROACHES. STRONG TO SEVERE STORMS ARE POSSIBLE...WITH DAMAGING WINDS THE MAIN THREAT. THE PRECIP SHOULD WIND DOWN BY EARLY OR MID WEDNESDAY MORNING AS THE COLD FRONT AND LOW PRESSURE HEAD EAST...WITH DRY WEATHER EXPECTED THOUGH THE REMAINDER OF THE DAY. COULD SEE SOME LOWER VSBYS IN STORMS TONIGHT...BUT OTHERWISE SHOULD REMAIN VFR OVERNIGHT. MAY SEE SOME MVFR CIGS FOR A COUPLE HOURS TOMORROW MORNING...BUT WILL LIKELY RETURN TO VFR BY LATE MORNING OR AFTERNOON AS MIXING INCREASES. NOT A LOT OF CONFIDENCE IN THE LOWER CIGS FOR TOMORROW...SO WILL KEEP VFR IN TAFS FOR NOW. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...DAVIS TONIGHT/WEDNESDAY AND AVIATION/MARINE...DDV WEDNESDAY NIGHT THROUGH TUESDAY...MBK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
805 PM CDT TUE AUG 6 2013 .MESOSCALE DISCUSSION... ISSUED AT 805 PM CDT TUE AUG 6 2013 CONVECTION CONTINUES ACROSS CENTRAL MINNESOTA AND NOW INTO PORTIONS OF NORTHWEST WISCONSIN AS DPVA SPREADS DOWNSTREAM. STILL LOOKING AT THE EARLIEST ARRIVAL TIME INTO THE FORECAST AREA BEING BETWEEN 830 AND 9 PM...IN THE LAKE CITY MN AND WESTERN TAYLOR COUNTY AREAS. MLCAPE STILL LOOKS FAVORABLE FOR THE STORMS TO CONTINUE WITH VALUES OF 1000-1500 J/KG ACROSS MUCH OF THE FORECAST AREA AS OF 00Z PER RAP ANALYSIS. ONE THING OF INTEREST IS THE WARM NOSE AT 800MB ON THE 00Z MPX SOUNDING. 06.22Z LOCAL WRF RUN AS WELL AS THE 06.18Z NAM BOTH SUGGEST THE BULK OF THE CONVECTION WILL END UP STAYING MAINLY ALONG AND NORTH OF I-94. IT APPEARS THE REASON IS THAT THIS WARM NOSE AT 800MB IS A FEW DEGREES WARMER ACROSS SOUTHERN MN...CAPPING CONVECTION DESPITE THE COLD FRONT PUSHING THROUGH THERE. 00Z RAP ANALYSIS ALSO DEPICTED A 100-150 J/KG MLCIN IN SOUTHWEST MN...WHICH THE SOUTHWEST WINDS HELP ADVECT AHEAD OF THE SOUTHWARD DROPPING FRONT. SEVERE THUNDERSTORM WATCH WAS ISSUED ABOUT A HALF HOUR AGO ENCOMPASSING MOST AREAS NORTH OF I-90...MINUS DODGE...OLMSTED AND MOWER COUNTIES IN MN. WATCH AREA BASICALLY HITS THE EDGE OF THE CAPPING AND THE TRACK OF THE SHORTWAVE. LARGE HAIL MAY BE AN INITIAL CONCERN WITH THE CONVECTION AS IT COMES INTO THE FORECAST AREA...BUT ANTICIPATING AN EVOLUTION TOWARDS WIND AS COLD POOLS CONTINUE TO DEVELOP. HAVE NOTICED WIND GUSTS BECOMING MUCH MORE APPARENT ON OBSERVATIONS IN CENTRAL MN...WITH GUSTS OF 41 KT AT MSP...24 KT AT LITCHFIELD AND 36 KT AT WILLMAR. && .SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT) ISSUED AT 305 PM CDT TUE AUG 6 2013 MAIN FORECAST CONCERNS THIS PACKAGE...SHRA/TSRA CHANCES AND SEVERE THREAT TONIGHT...TEMPERATURES THRU THE PERIOD. 18Z DATA ANALYSIS HAD LOW PRESSURE CENTERED NEAR THE MN/ND/SD BORDER. WEAK WARM FRONT EXTENDED FROM THE LOW TO NEAR THE MN/WI BORDER WHILE A SECOND TROUGH/FRONT EXTENDED INTO SOUTHWEST MN/WESTERN IA. INSTABILITY CONTINUED TO BUILD IN AREAS SOUTH OF THE WARM FRONT... WHERE PLENTY OF SUNSHINE WAS HELPING PUSH TEMPS INTO THE LOWER 80S AND SOUTH TO SOUTHWEST SFC-850MB FLOW WAS INCREASING SFC DEW POINTS INTO THE MID/UPPER 60S ACROSS MUCH OF IA/NEARBY AREAS. CONVECTION SINCE LATE MORNING CONFINED TO CENTRAL MN/NORTHWEST WI...EAST OF THE LOW AND NORTH OF THE WARM FRONT. WV IMAGERY SHOWING SHORTWAVE ENERGY SPREADING FROM THE DAKOTAS/MT INTO MN. NO MAJOR PROBLEMS NOTED IN 06.12Z MODEL INITIALIZATIONS. GFS SFC DEW POINT ANALYSIS WITH ITS USUAL POOR DEPICTION OF REALITY AT 12Z. SOLUTIONS SIMILAR FOR TONIGHT THRU WED NIGHT WITH PASSAGE OF THE COLD FRONT TONIGHT THEN COOLER/DRIER CAN HIGH PRESSURE BUILDING IN FOR WED/WED NIGHT. DPROG/DT OF 500MB HGTS AT 06.12Z SHOWED THE MODEL RUNS OF 04.12Z AND 05.12Z VERIFIED WELL ACROSS NOAM/EASTERN PAC WITH LATEST RUNS OFFERING A TIGHT CONSENSUS OF THE EARLIER RUNS. CONSENSUS TIGHTER AS THE MT/DAKOTAS SHORTWAVE ENERGY MOVES ACROSS THE REGION TONIGHT. FOR WED/WED NIGHT LATEST CONSENSUS FAVORS MORE EASTERLY OF EARLIER MODELS AS THE LOW JUST SOUTHWEST OF HUDSONS BAY LOW SINKS SLOWLY SOUTH INTO WESTERN ONT BY 12Z THU. CHECK OF OBS VS. MODEL DATA AT 18Z SHOW ALL WERE REASONABLE WITH THE ND/MN/SD BORDER LOW BUT WERE ON THE WEAK SIDE WITH THE FRONTS/TROUGHS TO THE EAST/SOUTH OF THE LOW. MODELS GENERALLY A BIT ROBUST WITH THE DEW POINT INCREASE INTO EASTERN SD/WESTERN MN AHEAD OF THE LOW. MODELS STRUGGLED WITH 12-18Z PRECIP ACROSS MUCH OF THE UPPER MIDWEST... BEING TOO WIDESPREAD. NO ONE MODEL FAVORITE AND SIDED WITH THE MODEL/ENSEMBLE CONSENSUS. WITH DETAIL DIFFERENCES IN CONVECTIVE EVOLUTION LATE THIS AFTERNOON/EVENING...SHORT-TERM FCST CONFIDENCE AVERAGE TONIGHT...THEN GOOD WED/WED NIGHT UNDER HIGH PRESSURE. IN THE SHORT TERM..LOW AND COLD FRONT MOVE EAST THRU THIS EVENING INTO THE MOIST/UNSTABLE AIRMASS OVER THE AREA. THIS AS THE DAKOTAS/ MT SHORTWAVE ENERGY AND SOME 500-300MB PV ADVECTION PIVOT SOUTHEAST ACROSS MN/WI. THIS WITH 0-6KM SHEAR IN THE 40-50KT RANGE. CONVECTION EXPECTED TO INITIATE ALONG THE SOUTHWEST MN/WESTERN IA TROUGH/FRONT LATE THIS AFTERNOON THEN SPREAD EAST INTO/ACROSS THE FCST AREA THIS EVENING INTO THE EARLY OVERNIGHT HOURS. SOME OF THE TSRA LOOKING TO BE SEVERE THIS EVENING...SEE SWODY1 FOR MORE DETAILS. PREVIOUS FCST GRIDS ALREADY HAD SHRA/TSRA CHANCES CENTERED ON THIS EVENING IN THE 70-80 PERCENT RANGE...JUST TRENDED FOR A BIT MORE OF THE EXPECTED TIMING OF THE PRECIP/FRONT ACROSS THE FCST AREA OVERNIGHT. GOOD MODEL CONSENSUS FOR THE COLD FRONT TO BE EAST/SOUTH OF THE FCST AREA BY 12Z WED WITH LOWER LEVEL COLD ADVECTION/SUBSIDENCE/DRYING SPREADING SOUTH ACROSS THE AREA IN ITS WAKE. TRENDED FCST GRIDS DRY FOR WED AS CAN HIGH PRESSURE SINKS SOUTH INTO THE UPPER MIDWEST. CENTER OF THE HIGH DRIFTS OVERHEAD WED NIGHT WITH WHAT SHOULD BE LIGHT WINDS/MOSTLY CLEAR-CLEAR SKIES. CONCERN RETURNS TO THE POTENTIAL FOR LATE NIGHT/EARLY MORNING RADIATIONAL FOG. GIVEN THE TIME OF YEAR AND WHAT SHOULD BE RATHER WIDESPREAD RAINS TONIGHT AND SOME EVAPO-TRANSPIRATION DEW POINT RECOVERY WED EVENING...DID ADD PATCHY VALLEY FOG TO FCST GRIDS FOR LATE WED NIGHT/EARLY THU MORNING. WITH NO ONE MODEL FAVORITE...USED A BLEND OF THE NUMERICAL TEMP GUIDANCE FOR LOWS/HIGHS TONIGHT THRU WED NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 305 PM CDT TUE AUG 6 2013 MAIN FORECAST CONCERNS FOR THURSDAY THROUGH FRIDAY NIGHT...SHRA/TSRA CHANCE MAINLY NORTH OF I-90 THU NIGHT...TEMPERATURES. MODELS CONTINUE WITH TIGHTENING CONSENSUS THU/THU NIGHT AS THE ONTARIO MID LEVEL LOW MOVES EAST AND A STRONGER SHORTWAVE ROTATES AROUND ITS BACKSIDE AND INTO THE REGION. BY FRI/FRI NIGHT TIMING DIFFERENCES BEGIN TO INCREASE WITH THE EASTWARD PROGRESS OF THE MID LEVEL LOW. OVERALL TREND THU THRU FRI NIGHT FAVORS FASTER OF EARLIER MODELS WITH THIS LOW MOVING EAST. FCST CONFIDENCE FOR THE THU-FRI NIGHT PERIOD IS AVERAGE TO GOOD. CAN HIGH PRESSURE REMAINS OVER THE AREA THU FOR WHAT SHOULD BE A DRY/QUIET/SEASONABLY COOL DAY. STRONGER TREND AMONG THE MODELS WITH THE SHORTWAVE TO DROP ACROSS THE REGION THU NIGHT SENDS ANOTHER SFC TROUGH/COLD FRONT INTO/ACROSS THE AREA. THIS RESULTS IN AN INCREASING LOWER LEVEL THERMO-DYNAMIC FORCING SIGNAL TO PUSH INTO THE FCST AREA THU NIGHT. PW VALUES PROGGED INTO THE 1 TO 1.25 INCH RANGE THU NIGHT...ALONG WITH WEAK TO MODEST 850-500MB FN CONVERGENCE. THIS LOWER LEVEL FORCING/LIFT DOES WEAKEN THRU THU NIGHT AS THE SHORTWAVE ENERGY SHEARS EAST AND THE FRONT LOSES ITS PUSH. HOWEVER...DID CONTINUE A 20-30 PERCENT SHRA/TSRA CHANCE ACROSS THE NORTHWEST HALF OF THE FCST AREA THU EVENING...THEN A SMALL SHRA CHANCE ACROSS MOST OF THE FCST AREA LATE THU NIGHT AS REMNANTS OF THE FRONT AND LIFT PUSH TOWARD THE WI/IL BORDER. FRI/FRI NIGHT LOOKING TO BE DOMINATED BY LOW LEVEL COLD ADVECTION/SUBSIDENCE/ DRYING AS YET ANOTHER CANADIAN HIGH BUILDS SOUTH INTO THE UPPER MIDWEST...UNDER THE PERSISTENT NORTHWEST FLOW ALOFT. MAY YET NEED TO ADD LATE NIGHT/EARLY MORNING VALLEY FOG MENTION TO GRIDS CENTERED ON 12Z SAT BUT PLENTY OF TIME TO SORT OUT THOSE DETAILS. USED A BLEND OF THE NUMERICAL GUIDANCE HIGHS/LOWS THU THRU FRI THEN FAVORED COOLER OF GUIDANCE LOWS WITH CAN HIGH SETTLING OVERHEAD FRI NIGHT. FOR SATURDAY THRU TUESDAY... THE MEDIUM RANGE MODEL RUNS OF 06.00Z/06.12Z ARE IN REASONABLE AGREEMENT SAT-SUN AS THE 500MB FLOW OVER THE WEST COAST STAYS BLOCKY AND A RATHER LARGE VORTEX REMAINS DOWNSTREAM OVER EASTERN CAN. SOME CONSENSUS FOR A STRONGER SHORTWAVE TROUGH TO ROTATE AROUND THE WEST SIDE OF THIS VORTEX AND INTO THE UPPER MIDWEST SUNDAY. TREND FROM 05.00Z RUNS IS FOR MORE TROUGHING/MID LEVEL LOW TO REMAIN NEAR JAMES BAY INTO EARLY NEXT WEEK. THE BLOCKY WESTERN NOAM PATTERN PERSISTS INTO THE MIDDLE OF NEXT WEAK...WITH THE EAST HALF OF NOAM REMAINING UNDER TROUGHING AND MORE IMPORTANTLY THE WESTERN GREAT LAKES STAYING UNDER NORTHWEST FLOW ALOFT. AS HAS BEEN THE CASE THE PAST WEEK OR SO...CONFIDENCE FOR DAY 4-7 TEMPS REMAINING NEAR OR BELOW NORMAL IS GOOD. CONFIDENCE IN PRECIP CHANCES FOR SAT-TUE BELOW AVERAGE DUE TO TYPICAL NORTHWEST FLOW SHORTWAVE TIMING/DETAIL DIFFERENCES... ESPECIALLY BY MON/TUE. CANADIAN HIGH PRESSURE IS IN PLACE OVER THE UPPER MIDWEST TO START THE WEEKEND...AND WITH LITTLE PROGRESSION OF THE FLOW PATTERN AND CONTINUED NORTHWEST FLOW ALOFT...MODEL SIGNAL IS FOR SOME FORM OF CANADIAN HIGH PRESSURE TO REMAIN OVER OR NEAR THE REGION WELL INTO NEXT WEEK. VARIOUS MODELS BRING SMALL SHRA/TSRA CHANCES TO THE AREA WITH PASSING SHORTWAVES FOR SUN-TUE. GIVEN THE LOOSE CONSENSUS FOR A STRONGER SHORTWAVE TO DROP ACROSS THE REGION SUNDAY...WITH INDICATIONS OF A SFC/LOWER LEVEL TROUGH...A ROUND OF MOISTURE INCREASE AND THERMO-DYNAMIC FORCING...A SMALL SHRA/TSRA CHANCE SUN/SUN NIGHT LOOKS REASONABLE. WITH HGTS LOOKING TO RISE MON/TUE AND THE SFC HIGH REMAINING OVER THE REGION...DAYS 6/7 LOOK TO TREND MORE DRY RATHER THAN WET. HOWEVER GIVEN WEAK RIPPLES IN THE FLOW AND COOLER TEMPS ALOFT...CANNOT COMPLETELY RULE OUT A SHRA OR TSRA MON/ TUE AND LEFT THE SMALL MODEL/ENSEMBLE CONSENSUS RAIN CHANCES THESE DAYS. SAT-TUE TEMPS REMAINING AROUND A CATEGORY BELOW NORMAL...PER THE MODEL/ENSEMBLE CONSENSUS...APPEAR WELL TRENDED AT THIS TIME. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 625 PM CDT TUE AUG 6 2013 NUMEROUS SHOWERS AND STORMS ENCOMPASSED MUCH OF WEST CENTRAL MINNESOTA AS OF 23Z. THIS PRECIPITATION STILL LOOKS POISED TO IMPACT THE TAF SITES...BUT AT A LATER TIME THAN PREVIOUSLY FORECAST. HAVE DELAYED THE STORM ARRIVAL TO AT LEAST 02-03Z AT RST AND 03-04Z AT LSE. THEY SHOULD LAST ABOUT 3 HOURS AND THEN EXIT OFF TO THE SOUTHEAST WITH THE PASSAGE OF A COLD FRONT. ACCOMPANYING THE STORMS COULD BE SOME STRONG WIND GUSTS AND HAIL...BUT TOO MUCH UNCERTAINTY EXISTS TO INCLUDE THESE IN THE TAFS AT THIS TIME. HAVE INCLUDED A TEMPO FOR MVFR VISIBILITIES...THOUGH...SINCE THERE IS POTENTIAL FOR HEAVY DOWNPOURS. A FEW HOURS AFTER THE FRONTAL PASSAGE...COOLER AIR RUNNING INTO THE MOIST AIRMASS IN PLACE IS LIKELY TO LEAD TO A STRATUS DECK...WITH IFR CONDITIONS. THESE CEILINGS ARE EXPECTED TO IMPROVE THROUGH THE MORNING AS DAYTIME MIXING AND NORTHWEST WINDS DRIVE IN DRIER AIR INTO THE TAF SITES. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE...AJ SHORT TERM...RRS LONG TERM....RRS AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
310 PM CDT MON AUG 5 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 310 PM CDT MON AUG 5 2013 THE NEXT 24 TO 36 HOURS WILL FEATURE A MORE ACTIVE PERIOD WITH A FEW WEATHER SYSTEMS TO CONTEND WITH INCLUDING PRECIPITATION CHANCES THIS EVENING...FOG OVERNIGHT...AND THEN SEVERE THREAT TUESDAY AFTERNOON/EVENING. LATEST WATER VAPOR COMBINED WITH RAP 500MB HEIGHTS SHOW BROAD NORTHWEST FLOW EAST OF THE ROCKIES...WITH NUMEROUS EMBEDDED SHORTWAVE TROUGHS. ONE CURRENTLY MOVING THROUGH MINNESOTA/IOWA...WHILE UPSTREAM ACROSS ALBERTA SITS A MORE VIGOROUS WAVE. FINALLY...A CLOSED POLAR VORTEX RESIDES NEAR HUDSON BAY. FOR THIS EVENING INTO TONIGHT...WILL CARRY A SLIGHT CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS UNTIL UPPER LEVEL SHORTWAVE COMPLETELY EXITS THE AREA. DESPITE SURFACE TROUGH LAGGING BEHIND...AND BUILDING INSTABILITY WITH CLEARING SKIES...SUBSIDENCE IN THE WAKE OF THE UPPER LEVEL SHORTWAVE AND SOME LOW TO MID LEVEL DRYING SHOULD PRECLUDE THE DEVELOPMENT OF ADDITIONAL SHOWERS/STORMS. HAVE ADDED PATCHY TO AREAS OF FOG FOR PARTS OF WISCONSIN...INCLUDING THE MS AND WISCONSIN RIVER VALLEYS OVERNIGHT AS A WEAK SURFACE HIGH BUILDS IN THE WAKE OF THE DEPARTING SYSTEM AND AHEAD OF THE APPROACHING COLD FRONT. NICE SETUP WITH TODAY/S COOL...CLOUDY CONDITIONS AND RECENT RAINFALL...THEN CLEARING SKIES LATE THIS EVENING. SURFACE WIND FIELD DROPS TO 5 KTS OR LESS...AND SOUNDINGS SHOW DECENT BOUNDARY LAYER SATURATION THOUGH TRY TO SHOW A STIFF BREEZE AT ABOUT 500 FT. COULD BE A MORE WIDESPREAD FOG SCENARIO INSTEAD OF JUST THE RIVER VALLEYS...SOMETHING TO WATCH THIS EVENING. THE ALBERTA SHORTWAVE TROUGH THEN TAKES AIM ON THE AREA...AND WILL BE THE FOCUS FOR PUSHING THROUGH A SURFACE COLD FRONT TUESDAY EVENING. BUILDING INSTABILITY DURING THE DAY IS SOMEWHAT CONDITIONAL ON AN EARLY MORNING MCS EXPECTED WELL TO OUR WEST...BUT BY MID AFTERNOON...MUCAPE BETWEEN 1500 AND 2000 J/KG COULD BE REALIZED. THE SHEAR ENVIRONMENT IS MORE THAN SUFFICIENT FOR SEVERE STORMS AS 250 MB JET MAX OVERHEAD PUTS 40 TO 50 KTS OF EFFECTIVE SHEAR ACROSS MUCH OF THE AREA...AND THE LOW-LEVELS HAVE FAVORABLE LAPSE RATES. HODOGRAPHS SHOW MODEST LOOPING. OVERALL...IF INSTABILITY CONDITIONS ARE MET...ENVISION STORM MODE TO FAVOR RIGHT MOVING CLUSTER OF CELLS EVOLVING INTO BOWING SEGMENTS WITH THE MAIN THREAT LARGE HAIL AND DAMAGING WINDS. 0-1 KM SHEAR ENVIRONMENT IS UNIDIRECTIONAL SO NOT EXPECTING A FAVORABLE TORNADO ENVIRONMENT HOWEVER WITH THAT SAID...ANY LINGERING SURFACE BOUNDARIES COULD COMPLICATE THAT. MODEL AGREEMENT ON FRONTAL TIMING IS HIGHER WITH THE 05.12Z GUIDANCE...WHICH ADDS CONFIDENCE TO THE LATE AFTERNOON AND EVENING PRECIPITATION CHANCES. THE NAM REMAINS A FASTER OUTLIER WHILE THE GEM/GFS/ECMWF ARE CONSISTENT WITH A 00 TO 06Z PASSAGE. EARLIER FORECAST TIMING FOR POPS LOOK GOOD SO HAVE CARRIED SIMILAR THINKING. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 310 PM CDT MON AUG 5 2013 THE BIG STORY IN THE LONG TERM WILL BE A CONTINUATION OF THE UNSEASONABLY COOL WEATHER PATTERN AS THE MAIN POLAR VORTEX / CLOSED UPPER LOW WOBBLES ACROSS SOUTHERN CANADA. OUTSIDE OF SCATTERED DAYTIME CUMULUS FIELD ACROSS WISCONSIN WEDNESDAY...HIGH PRESSURE DOMINATES WITH PLEASANT CONDITIONS. HIGHS LOWER TO MIDDLE 70S. ANOTHER SIMILAR DAY THURSDAY...THOUGH BY EVENING INTO THE NIGHT THE CLOSED UPPER LOW WOBBLES FURTHER TO THE SOUTH AS ANOTHER PIECE OF ENERGY ROUNDS THE BASE. THIS TRIES TO DRIVE A SURFACE COLD FRONT WITH SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MINNESOTA INTO WISCONSIN. HOWEVER...BETTER DYNAMICS AND MOISTURE TRANSPORT REMAIN IN THE WEST AND NORTH FORECAST...AND THE FRONT WASHES OUT BEFORE MAKING IT VERY FAR INTO THE FORECAST AREA. WILL CONTINUE SLIGHT CHANCES IN THE NORTHWEST WHILE THE REST OF THE AREA WILL LIKELY ONLY SEE INCREASED CLOUD COVER. IN THE WAKE OF THIS SHORTWAVE TROUGH...A REINFORCING SHOT OF COOLER AIR SURGES IN AS SEEN BY 850 MB TEMPERATURES FRIDAY AND SATURDAY DROPPING TO THE 8 TO 10C RANGE. HIGHS IN THE 70S AND OVERNIGHT LOWS COULD DIP INTO THE UPPER 40S TO LOWER 50S...ESPECIALLY FOR THE TYPICAL COOLER SPOTS OF CENTRAL WISCONSIN. DEPENDING ON THE HIGH PRESSURE AXIS...COULD SEE A FEW MORNINGS OF RIVER VALLEY FOG AS WELL. OVERALL...VERY NICE CONDITIONS FOR EARLY/MID AUGUST POSSIBLE ACROSS THE ENTIRE UPPER MIDWEST FROM FRIDAY INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1221 PM CDT MON AUG 5 2013 AN UPPER LEVEL DISTURBANCE CONTINUED TO SLIDE SOUTHEAST ACROSS MN/WI AT MID DAY. BULK OF THE SHRA/TSRA HAD MOVED SOUTHEAST OF THE TAF SITES...WITH THE MAIN FORCING/LIFT ALSO MOVING OFF TO THE EAST/ SOUTH. LEFT 18Z TAF SET SHRA/TSRA-FREE WITH CONVECTION FOR THE REST OF THE AFTERNOON/EVENING LOOKING TO BE WDLY SCT AT MOST WITH MUCH UNCERTAINTY IF ONE WOULD CROSS EITHER THE KRST/KLSE AIRPORTS. BIGGER CONCERN IS LOWER LEVEL MOISTURE/CLOUDS IN THE WAKE OF THIS MORNING/S CONVECTION ADVECTING INTO THE AREA ON SOUTH WINDS. RATHER WIDESPREAD MVFR AND LCL IFR CIGS AROUND THE AREA AT MID-DAY. WITH THE MAIN LOWER LEVEL TROUGH REMAINING WEST OF THE AREA...THESE LOOKING TO PERSIST THRU THE AFTERNOON INTO THE EVENING. MODEL CONSENSUS BUILDS WEAK HIGH PRESSURE INTO THE AREA LATER THIS EVENING/OVERNIGHT. CONTINUED THE TREND OF THE LOWER CLOUD DECKS BECOMING SCT BY LATE EVENING...BUT WITH THE MOIST BOUNDARY LAYER FROM THIS MORNINGS RAINS THIS SETS THE AREA UP FOR RADIATIONAL BR/FG LATER TONIGHT INTO TUE MORNING. ADDED VCFG AND TEMPO 2SM BR TO KLSE IN THE 9-14Z PERIOD AND MVFR BR TO KRST IN ROUGHLY THE SAME PERIOD. ONCE THE BR/FG LIFT/BURN OFF TUE MORNING...GENERALLY GOOD VFR THEN EXPECTED THRU MUCH OF TUE WITH SOME DRIER IN THE 925-850MB LAYER MIXING TOWARD THE SFC WITH DIURNAL WARMING/MIXING THRU THE DAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...ZT LONG TERM....ZT AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1028 AM CDT MON AUG 5 2013 .UPDATE...FORECAST HAS BEEN MODIFIED SIGNIFICANTLY TO LOWER POPS ESPECIALLY IN EASTERN CWA. TRENDS IN HRRR SUPPORT MORE IN THE WAY OF SCATTERED COVERAGE THIS AFTERNOON. INITIAL PRECIP AREA HAS DIMINISHED AND REMNANTS HAVE SHIFTED SOUTH AND SOUTHEAST OF THE CWA. UPSTREAM BREAKS IN THE CLOUD COVER ALONG WITH THE SWIFT UPPER NW FLOW...JET STREAM DYNAMICS SHOULD RESULT IN AT LEAST SCATTERED REDEVELOPMENT PER THE HRRR. SEEING SOME OF THIS UPSTREAM IN NE IA...WITH OTHER WEAKER DEVELOPMENT NORTH AND NORTHWEST OF LA CROSSE. PC && .AVIATION/18Z TAFS/...MID LEVEL DECK ASSOCIATED WITH BATCH OF SHRA THAT MOVED THROUGH GRADUALLY SHOWING SOME DECREASE ACROSS SC WI. MORE SHRA/ISOLD TSRA DEVELOPMENT EXPECTED THIS AFTERNOON/THIS EVENING WITH MID LEVEL JET STREAK AND INCREASED MOISTURE. WITH WEAKER GRADIENT IN PLACE TONIGHT INTO EARLY TUESDAY WILL HAVE TO WATCH FOR STRATUS/FOG DEVELOPMENT. CURRENT TAFS HAVE THIS HANDLED WELL AND SEE NO REASON TO DEVIATE TOO MUCH FROM THE PRIOR THINKING. PC && .PREV DISCUSSION... /ISSUED 329 AM CDT MON AUG 5 2013/ TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH MID/UPPER LEVEL NORTHWEST FLOW CONTINUES WITH A 112 KNOT 250 MB JET MAX THAT REACHES WISCONSIN DURING THE EARLY MORNING HOURS. THE RIGHT ENTRANCE REGION BRINGS AN AREA OF MODERATE UPPER DIVERGENCE INTO WISCONSIN BY SUNRISE. THE JET MAX REMAINS ACROSS SOUTHERN WISCONSIN THROUGH THE AFTERNOON BEFORE WEAKENING TONIGHT. SEVERAL 500 MB CYCLONIC VORTICITY MAXIMUM MOVE ACROSS SOUTHERN WISCONSIN TODAY AND TONIGHT...SOME LIKELY CONVECTIVELY INDUCED. MODERATE 700 MB UPWARD MOTION PUSHES INTO WEST CENTRAL WISCONSIN BY SUNRISE AND ACROSS SOUTHERN WISCONSIN THIS MORNING. THE 700 MB LAYER SATURATES DURING THE EARLY MORNING AS THE 850/700 MB MOISTURE CONVERGENCE INCREASES IN THE BAROCLINIC ZONE ACROSS SOUTHWEST WISCONSIN BEFORE WARM AIR ADVECTION BEGINS. THE LARGE SURFACE HIGH WILL BE CENTERED OVER OHIO BY SUNRISE WITH WEAK SOUTH WINDS ON THE BACK SIDE OF THE HIGH AHEAD OF A WEAK SURFACE TROUGH OVER MINNESOTA. SHOWERS SHOULD PUSH INTO AREAS WEST OF MADISON AFTER SUNRISE AND SPREAD ACROSS SOUTHEAST WISCONSIN LATER THIS MORNING. LIMITED ELEVATED CAPE...BUT WITH 100 JOULES/KG SEEN ON THE SOUNDINGS IF LIFTED FROM 8 THSD FT...ISOLATED/SCATTERED THUNDERSTORMS ARE EXPECTED. THE MAIN BAND OF SHOWERS WILL EXIT THE SOUTHEAST LATER DURING THE AFTERNOON. HOWEVER MOISTURE REMAINS IN PLACE...AND WITH WEAK 850/700 MB MOISTURE CONVERGENCE CONTINUING TONIGHT...MORE SHOWERS WILL BE POSSIBLE. LOW LEVELS REMAIN MOIST AND THE NAM DEVELOPS ALMOST 500 JOULES/KG OF CAPE LATE TONIGHT ACROSS THE FORECAST AREA. THEREFORE THE CHANCE OF THUNDERSTORMS WILL CONTINUE WITH THE WEAK LOW LEVEL LIFT. TUESDAY AND WEDNESDAY...FORECAST CONFIDENCE...MEDIUM LOOKS PRETTY QUIET DURING THE DAY TUESDAY. THE NAM IS SHOWING CONVECTION THROUGH THE DAY...BUT OTHER MODELS SHOWING MORE OF A CAP TO KEEP THINGS MAINLY DRY. KEPT POPS ON THE LOW END. SHOULD SEE SHOWERS/STORMS IN THE EVENING AND OVERNIGHT AS THE COLD FRONT AND MAIN SHORTWAVE MOVE THROUGH...SO KEPT LIKELY POPS GOING. EXPECTING AT LEAST A LITTLE SUNSHINE TUESDAY...SO STILL THINK LOW TO EVEN MID 80S POSSIBLE WITH 925 MB TEMPS IN THE 21-23C RANGE. SHOULD SEE THE PRECIP EXIT WEDNESDAY MORNING...TURNING DRY IN THE AFTERNOON AS HIGH PRESSURE BEGINS TO BUILD IN BEHIND THE FRONT. SHOULD SEE HIGH TEMPS NEAR TO A COUPLE DEGREES BELOW NORMAL. THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE...MEDIUM GENERALLY LOOKS PLEASANT TO END THE WEEK...AS HIGH PRESSURE SLIDES IN BEHIND THE DEPARTING FRONT THURSDAY WITH TEMPS A BIT BELOW NORMAL. WILL SEE NEAR NORMAL TEMPS FRIDAY WITH A WEAK FRONT AT SOME POINT. A SHOWER OR TWO IS NOT OUT OF THE QUESTION...BUT IT LOOKS LIKE MAINLY A DRY FRONTAL PASSAGE. HIGH PRESSURE WILL THEN LIKELY RETURN SATURDAY...WITH CURRENT MODELS SUGGESTING DRY WEATHER THROUGH THE WEEKEND WITH TEMPS A BIT BELOW NORMAL. AVIATION/12Z TAFS/... EXPECT THE CLOUDS TO THICKEN AND LOWER THIS MORNING AHEAD OF THE APPROACHING JET MAX AND UPWARD MOTION. SHOWERS SHOULD PUSH INTO AREAS WEST OF MADISON AROUND SUNRISE AND ACROSS THE SOUTHEAST DURING THE MORNING. WIDESPREAD MVFR CIGS/VSBYS EXPECTED...AND WITH LOW LEVEL MOISTURE IN PLACE SOME IFR CIGS/VSBYS TONIGHT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ TODAY/TONIGHT AND AVIATION/MARINE...HENTZ TUESDAY THROUGH SUNDAY...DDV
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
1031 PM PDT TUE AUG 6 2013 .UPDATE... KRGX RADAR HAS BEEN WORKING FINE OVER THE LAST SEVERAL HOURS WITH NO PROBLEMS. A FEW STORMS EARLIER OVER NORTHERN WASHOE COUNTY AND SURPRISE VALLEY CALIFORNIA PRODUCED SOME STRONG OUTFLOW WINDS, ALTHOUGH THE CELLS DID NOT LOOK IMPRESIVE BY ANY MEANS ON RADAR. A GUST OF 58 MPH WAS RECORDED AT SURPRISE VALLEY RAWS AROUND 9PM THIS EVENING. NOCTURNAL CONVECTION CONTINUES TO BLOSSOM OVER NORTHWESTERN NEVADA AND NORTHEASTERN CALIFORNIA AT THIS HOUR. HAVE UPDATED THE FORECAST FOR OVERNIGHT AND EARLY WEDNESDAY MORNING TO BRING ISOLATED THUNDERSTORMS FURTHER SOUTH INTO THE RENO-TAHOE AREA, AS WELL AS FURTHER EAST INTO PERSHING AND CHURCHILL COUNTIES. LATEST HRRR MODEL RUNS HAVE SHOWN CONVECTIVE DEVELOPMENT AFTER MIDNIGHT IN THESE AREAS AS THE NEGATIVELY TILTED SHORTWAVE MOVES INTO THE AREA. THERE IS PLENTY OF ELEVATED INSTABILITY AS SEEN ON LATEST SATELLITE IMAGERY. ANY STORMS THAT DO DEVELOP WILL BE VERY HIGH BASED AND FAST MOVING WITH LITTLE RAINFALL POSSIBLE. HOON && .PREVIOUS DISCUSSION... /ISSUED 546 PM PDT TUE AUG 6 2013/ UPDATE... MADE AN UPDATE TO THE FORECAST TO INCLUDE AREAS OF SMOKE AND HAZE IN MONO AND ALPINE COUNTIES TONIGHT AND WEDNESDAY. ALSO, THE WSR- 88D RADAR ON VIRGINIA PEAK HAS EXPERIENCED ANOTHER OUTAGE OF WIDEBAND COMMUNICATIONS. TECHNICIANS HAVE BEEN ALERTED TO THE OUTAGE AND ARE WORKING TO FIX THE PROBLEM AS SOON AS POSSIBLE. AS FOR THE STORMS ALONG THE SIERRA FRONT, WE CONTINUE TO MONITOR THE STORMS USING RADARS IN THE SACRAMENTO AND HANFORD CALIFORNIA. NONE OF THE STORMS LOOK PARTICULARLY STRONG, ALTHOUGH WITH THE VERY DRY BOUNDARY LAYER (AS SEEN ON THE 00Z SOUNDING), STRONG GUSTY OUTFLOW WINDS UP TO 50 MPH OR MORE ARE POSSIBLE WITH EVEN WEAK STORMS. HOON PREVIOUS DISCUSSION... /ISSUED 311 PM PDT TUE AUG 6 2013/ SYNOPSIS... LOW PRESSURE OFF THE CALIFORNIA COAST WILL EDGE CLOSER TO EASTERN CALIFORNIA AND WESTERN NEVADA THIS WEEK. INCREASING MOISTURE AND INSTABILITY FROM THE LOW WILL BRING THE THREAT OF THUNDERSTORMS THIS WEEK...MOST WIDESPREAD NORTH OF INTERSTATE 80. TEMPERATURES WILL FALL TO 5 TO 10 DEGREES BELOW AVERAGE LATE THIS WEEK. SHORT TERM... MAIN CHANGE TO THE SHORT TERM FORECAST WAS TO INCREASE THUNDERSTORM COVERAGE THURSDAY MORNING OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA NORTH OF SUSANVILLE AND LOVELOCK. LOOKING AT THE VISIBLE SATELLITE THIS AFTERNOON THERE ARE TWO AREAS OF NOTE. IN/NEAR THE SIERRA SOUTH OF HIGHWAY 50, DAYTIME HEATING AND SOUTHEAST FLOW ALOFT HAS ALLOWED CUMULUS TO BUILD UP THE CREST. SO FAR IN THE VISIBLE SATELLITE AND PER WEB CAMS, THE CUMULUS LOOKS MODEST BUT SEVERAL HOURS OF ADDITIONAL HEATING SHOULD ALLOW A FEW HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP AND SPREAD NORTH UP THE CREST INTO NORTHEAST CALIFORNIA AND INTO FAR WESTERN NEVADA. THE OTHER AREA OF NOTE IS NORTH OF GERLACH AND SUSANVILLE WHERE DIVERGENCE ALOFT BETWEEN THE COASTAL UPPER LOW AND A RIDGE AXIS OVER NORTHEAST NEVADA IS PRODUCING ELEVATED SHOWERS AND, RECENTLY, A THUNDERSTORM. MOVING ON TO THE FORECAST TONIGHT THROUGH THURSDAY NIGHT, THE UPPER LOW OFF THE NORTHERN CALIFORNIA COAST WILL MOVE SLOWLY EAST- NORTHEAST TOWARDS CAPE MENDOCINO. TWO UPPER WAVES WILL MOVE AROUND THE LOW, ONE TONIGHT AND THE SECOND THURSDAY. THE WAVES WILL BRING ISOLATED TO SCATTERED THUNDERSTORMS (BOTH ELEVATED AND SURFACE- BASED), WITH THE MOST WIDESPREAD THUNDERSTORMS EXPECTED NORTH OF INTERSTATE 80. AS FAR AS THE FIRST WAVE TONIGHT, IT IS CURRENTLY APPROACHING THE CALIFORNIA COAST WITH AN ASSOCIATED JET STREAK MOVING OVER THE SAN FRANCISCO AREA. THIS IS FIRING UP ELEVATED CONVECTION OVER NORTHERN CALIFORNIA AND, AS THE DISTURBANCE MOVES INLAND LATE TONIGHT, OVER LASSEN, NORTHERN WASHOE AND MODOC COUNTIES. THEY ARE ONLY EXPECTED TO BE ISOLATED AS THE MAIN UPPER FORCING REMAINS OVER NORTHERN CALIFORNIA AND SOUTHERN OREGON THROUGH WEDNESDAY MORNING. ON WEDNESDAY, THE FIRST UPPER WAVE WILL PASS INTO SOUTHERN OREGON. AFTER A FEW ISOLATED THUNDERSTORMS EARLY OVER FAR NORTHEAST CALIFORNIA AND NEAR THE SURPRISE VALLEY, DIURNAL CONVECTION WILL FIRE UP BY EARLY AFTERNOON. THE BEST COVERAGE SHOULD BE NORTH OF SUSANVILLE AND GERLACH AS A RESIDUAL MOISTURE BOUNDARY AND CONVERGENT WESTERLY FLOW DEVELOPS DOWNWIND OF LASSEN PEAK. ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE SOUTH OF HIGHWAY 50 IN THE BASIN AND RANGE AS WESTERLY WINDS KICK OFF THE SIERRA IN THE AFTERNOON AND EVENING. THAT AREA WILL BE MORE STABLE THAN FURTHER NORTH AS A DRY SLOT INVADES IN THE POST-WAVE AIRMASS SO STORMS MAY HAVE A LITTLE TROUBLE GETTING GOING THERE. WEDNESDAY NIGHT AND THURSDAY MORNING, ANOTHER ROUND OF NOCTURNAL CONVECTION IS POSSIBLE NORTH OF INTERSTATE 80 AS THE SECOND UPPER WAVE MOVES OVERHEAD. SEE THE FIRE WEATHER DISCUSSION FOR MORE DETAILS ON THAT WAVE. THURSDAY AFTERNOON AND EVENING A JET STREAK MOVES OVER THE NORTHERN SIERRA FOR A BETTER SHOT AT DIURNAL CONVECTION DOWN TO THE RENO-TAHOE AREA BY EARLY EVENING. SNYDER LONG TERM...FRIDAY THROUGH TUESDAY... FEW CHANGES TO THE EXTENDED FORECAST AS MEDIUM RANGE MODELS CONTINUE TO MAINTAIN GOOD AGREEMENT WITH THE CUTOFF LOW PRESSURE OVER THE WEST COAST. MAIN CHANGE WAS TO COOL HIGH TEMPERATURES ON FRIDAY AND SATURDAY A FEW DEGREES AS THE CORE OF THE LOW MOVES OVER NORTHERN CALIFORNIA AND FAR NORTHWEST NEVADA. ON FRIDAY ISOLATED THUNDERSTORMS WILL CONTINUE IN THE NORTHERN SIERRA NORTH OF LAKE TAHOE WITH THE POSSIBILITY OF NOCTURNAL STORMS CONTINUING MAINLY NORTH OF SUSANVILLE. ON SATURDAY ISOLATED THUNDERSTORMS MAY STILL BE POSSIBLE NORTH OF SUSANVILLE AS THE LOW LIFTS OUT OF THE AREA. FRIDAY SHOULD BE THE COLDEST DAY OF THE WEEK WITH TEMPERATURES IN WESTERN NEVADA IN THE MID 80`S AND MID 70`S IN THE SIERRA. BY SUNDAY THE LOW BEGINS TO WEAKEN AND MOVE NORTH INTO OREGON AS HIGH PRESSURE REBUILDS OVER THE FOUR CORNERS. THE BEST INSTABILITY MOVES NORTH WITH THE LOW PRESSURE LEAVING ONLY A FEW CUMULUS CLOUDS ALONG THE SIERRA. BY MONDAY TEMPERATURES WILL RETURN TO NORMAL WITH WESTERN NEVADA RETURNING TO AROUND 90 DEGREES AND THE SIERRA AROUND 80. TOLBY AVIATION... CUMULUS WITH ISOLATED HIGH-BASED STORMS ARE BUILDING NORTH IN AND NEAR THE SIERRA THIS AFTERNOON. OUTFLOW WINDS TO 40-45 KTS ARE POSSIBLE AROUND STORMS WITH THE PRIMARY CIG/VSBY RESTRICTIONS EXPECTED OVER HIGHER TERRAIN WHERE HEAVIER RAIN WILL REACH THE GROUND. STILL NOT PLANNING ON MENTIONING ANY THUNDER AT KTRK/KTVL/KRNO/KMMH TERMINALS THIS EVENING AS CLOUDS ARE PUSHING EAST OF THE CREST TOWARDS THE PINE NUT RANGE (EASTERN DOUGLAS COUNTY) BEFORE THEY REACH NORTH TO HIGHWAY 50. AS FAR AS SMOKE FROM FIRES WEST OF THE SIERRA CREST, IT WILL AFFECT VSBYS THROUGH THIS EVENING IN MONO COUNTY ESPECIALLY WEST OF BRIDGEPORT AND SOUTH OF MONO LAKE. ISOLATED THUNDERSTORMS MAY PERSIST OVER AREAS NORTH OF SUSANVILLE THROUGH THE NIGHT WITH GUSTY OUTFLOW WINDS. ON WEDNESDAY, THUNDERSTORMS SHOULD BE RESTRICTED TO SOUTH OF HIGHWAY 50 AND NORTH OF SUSANVILLE AND GERLACH. SNYDER FIRE WEATHER... BIGGEST CONCERN REMAINS THUNDERSTORMS THURSDAY. UNTIL THEN, STILL EXPECT ISOLATED THUNDERSTORMS NEAR AND EAST OF THE SIERRA CREST THIS EVENING. BUILDING CUMULUS ALREADY OVER MONO COUNTY, WITH SOME NOW DEVELOPING A LITTLE FURTHER NORTH. ONLY EXPECTING A FEW STORMS BUT THEY SHOULD BE DRY WITH VERY DRY LOW LEVELS AND STORM MOTIONS NWD AROUND 20 MPH. OTHER CONCERN IS IMPRESSIVE MID/UPPER LEVEL WAVE OFF POINT CONCEPTION. FORCING AHEAD OF IT IS IMPRESSIVE AND ALREADY GETTING A FEW ISOLATED C-G STRIKES OVER THE SACRAMENTO VALLEY SHOWING THE ELEVATED INSTABILITY. THIS WILL MOVE THROUGH OVERNIGHT WITH MODELS SHOWING IMPRESSIVE FORCING AND INSTABILITY AHEAD OF THE WAVE. IT LOOKS TO PASS THROUGH NW CA AND SW OREGON AFTER 12Z SO WE WILL ONLY BE ON THE FRINGE. WILL CONTINUE WITH ISOLATED DRY THUNDERSTORMS FOR LASSEN AND PLUMAS COUNTIES NORTH OF HWY 70 TONIGHT INTO EXTREME NW NEVADA. BEST ACTION WILL BE FURTHER NORTH AND WEST. DRIER AIR AND A BIT STRONGER WEST FLOW WILL OCCUR IN THE WAKE OF THE WAVE WEDNESDAY. THEREFORE, STILL EXPECT MAIN THREAT FOR THUNDERSTORMS NORTH OF SUSANVILLE/GERLACH. MAY SEE SOME SCT COVERAGE RIGHT NEAR THE OREGON BORDER WITH HYBRID WET/DRY STORMS. IT IS A CONCERN, BUT WITH LIMITED AREA AFFECT WILL NOT ISSUE A WATCH/WARNING THERE. AS FOR THURSDAY, AN UPPER WAVE IS EXPECTED TO MOVE IN THURSDAY MORNING WITH GOOD UPPER JET SUPPORT. IN ADDITION, MID-LEVEL MOISTURE WILL INCREASE WITH THUNDERSTORMS LIKELY TO START AROUND SUNRISE. THE BEST FORCING AND MOISTURE REMAIN NORTH OF I-80 WITH SCATTERED STORMS INTO THE AFTERNOON. LOW LEVEL MOISTURE WILL ALSO INCREASE DURING THE DAY, BUT THE FAST STORM MOTIONS OF 20-25 MPH WILL LIKELY KEEP THE STORMS IN A HYBRID WET/DRY MODE. HAVE ISSUED A WATCH FOR THE ZONES NORTH OF I-80; 270, 271, 278, 453, 458. 271 MAY BE A BIT TOO WET AS WE GO FURTHER INTO THE DAY THURSDAY, BUT GIVEN THE THREAT IN THE MORNING WHEN STORMS WOULD BE DRIER, I THOUGHT IT WOULD BE PRUDENT TO ADD IT. WALLMANN && .REV WATCHES/WARNINGS/ADVISORIES... NV...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING NVZ458. FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING NVZ453. CA...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING CAZ270-271-278. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
1021 PM PDT TUE AUG 6 2013 .UPDATE... KRGX RADAR HAS BEEN WORKING FINE OVER THE LAST SEVERAL HOURS WITH NO PROBLEMS. NOCTURNAL CONVECTION CONTINUES TO BLOSSOM OVER NORTHWESTERN NEVADA AND NORTHEASTERN CALIFORNIA AT THIS HOUR. HAVE UPDATED THE FORECAST FOR OVERNIGHT AND EARLY WEDNESDAY MORNING TO BRING ISOLATED THUNDERSTORMS FURTHER SOUTH INTO THE RENO-TAHOE AREA, AS WELL AS FURTHER EAST INTO PERSHING AND CHURCHILL COUNTIES. LATEST HRRR MODEL RUNS HAVE SHOWN CONVECTIVE DEVELOPMENT AFTER MIDNIGHT IN THESE AREAS AS THE NEGATIVELY TILTED SHORTWAVE MOVES INTO THE AREA. THERE IS PLENTY OF ELEVATED INSTABILITY AS SEEN ON LATEST SATELLITE IMAGERY. ANY STORMS THAT DO DEVELOP WILL BE VERY HIGH BASED AND FAST MOVING WITH LITTLE RAINFALL POSSIBLE. HOON && .PREVIOUS DISCUSSION... /ISSUED 546 PM PDT TUE AUG 6 2013/ UPDATE... MADE AN UPDATE TO THE FORECAST TO INCLUDE AREAS OF SMOKE AND HAZE IN MONO AND ALPINE COUNTIES TONIGHT AND WEDNESDAY. ALSO, THE WSR- 88D RADAR ON VIRGINIA PEAK HAS EXPERIENCED ANOTHER OUTAGE OF WIDEBAND COMMUNICATIONS. TECHNICIANS HAVE BEEN ALERTED TO THE OUTAGE AND ARE WORKING TO FIX THE PROBLEM AS SOON AS POSSIBLE. AS FOR THE STORMS ALONG THE SIERRA FRONT, WE CONTINUE TO MONITOR THE STORMS USING RADARS IN THE SACRAMENTO AND HANFORD CALIFORNIA. NONE OF THE STORMS LOOK PARTICULARLY STRONG, ALTHOUGH WITH THE VERY DRY BOUNDARY LAYER (AS SEEN ON THE 00Z SOUNDING), STRONG GUSTY OUTFLOW WINDS UP TO 50 MPH OR MORE ARE POSSIBLE WITH EVEN WEAK STORMS. HOON PREVIOUS DISCUSSION... /ISSUED 311 PM PDT TUE AUG 6 2013/ SYNOPSIS... LOW PRESSURE OFF THE CALIFORNIA COAST WILL EDGE CLOSER TO EASTERN CALIFORNIA AND WESTERN NEVADA THIS WEEK. INCREASING MOISTURE AND INSTABILITY FROM THE LOW WILL BRING THE THREAT OF THUNDERSTORMS THIS WEEK...MOST WIDESPREAD NORTH OF INTERSTATE 80. TEMPERATURES WILL FALL TO 5 TO 10 DEGREES BELOW AVERAGE LATE THIS WEEK. SHORT TERM... MAIN CHANGE TO THE SHORT TERM FORECAST WAS TO INCREASE THUNDERSTORM COVERAGE THURSDAY MORNING OVER NORTHEAST CALIFORNIA AND WESTERN NEVADA NORTH OF SUSANVILLE AND LOVELOCK. LOOKING AT THE VISIBLE SATELLITE THIS AFTERNOON THERE ARE TWO AREAS OF NOTE. IN/NEAR THE SIERRA SOUTH OF HIGHWAY 50, DAYTIME HEATING AND SOUTHEAST FLOW ALOFT HAS ALLOWED CUMULUS TO BUILD UP THE CREST. SO FAR IN THE VISIBLE SATELLITE AND PER WEB CAMS, THE CUMULUS LOOKS MODEST BUT SEVERAL HOURS OF ADDITIONAL HEATING SHOULD ALLOW A FEW HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP AND SPREAD NORTH UP THE CREST INTO NORTHEAST CALIFORNIA AND INTO FAR WESTERN NEVADA. THE OTHER AREA OF NOTE IS NORTH OF GERLACH AND SUSANVILLE WHERE DIVERGENCE ALOFT BETWEEN THE COASTAL UPPER LOW AND A RIDGE AXIS OVER NORTHEAST NEVADA IS PRODUCING ELEVATED SHOWERS AND, RECENTLY, A THUNDERSTORM. MOVING ON TO THE FORECAST TONIGHT THROUGH THURSDAY NIGHT, THE UPPER LOW OFF THE NORTHERN CALIFORNIA COAST WILL MOVE SLOWLY EAST- NORTHEAST TOWARDS CAPE MENDOCINO. TWO UPPER WAVES WILL MOVE AROUND THE LOW, ONE TONIGHT AND THE SECOND THURSDAY. THE WAVES WILL BRING ISOLATED TO SCATTERED THUNDERSTORMS (BOTH ELEVATED AND SURFACE- BASED), WITH THE MOST WIDESPREAD THUNDERSTORMS EXPECTED NORTH OF INTERSTATE 80. AS FAR AS THE FIRST WAVE TONIGHT, IT IS CURRENTLY APPROACHING THE CALIFORNIA COAST WITH AN ASSOCIATED JET STREAK MOVING OVER THE SAN FRANCISCO AREA. THIS IS FIRING UP ELEVATED CONVECTION OVER NORTHERN CALIFORNIA AND, AS THE DISTURBANCE MOVES INLAND LATE TONIGHT, OVER LASSEN, NORTHERN WASHOE AND MODOC COUNTIES. THEY ARE ONLY EXPECTED TO BE ISOLATED AS THE MAIN UPPER FORCING REMAINS OVER NORTHERN CALIFORNIA AND SOUTHERN OREGON THROUGH WEDNESDAY MORNING. ON WEDNESDAY, THE FIRST UPPER WAVE WILL PASS INTO SOUTHERN OREGON. AFTER A FEW ISOLATED THUNDERSTORMS EARLY OVER FAR NORTHEAST CALIFORNIA AND NEAR THE SURPRISE VALLEY, DIURNAL CONVECTION WILL FIRE UP BY EARLY AFTERNOON. THE BEST COVERAGE SHOULD BE NORTH OF SUSANVILLE AND GERLACH AS A RESIDUAL MOISTURE BOUNDARY AND CONVERGENT WESTERLY FLOW DEVELOPS DOWNWIND OF LASSEN PEAK. ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE SOUTH OF HIGHWAY 50 IN THE BASIN AND RANGE AS WESTERLY WINDS KICK OFF THE SIERRA IN THE AFTERNOON AND EVENING. THAT AREA WILL BE MORE STABLE THAN FURTHER NORTH AS A DRY SLOT INVADES IN THE POST-WAVE AIRMASS SO STORMS MAY HAVE A LITTLE TROUBLE GETTING GOING THERE. WEDNESDAY NIGHT AND THURSDAY MORNING, ANOTHER ROUND OF NOCTURNAL CONVECTION IS POSSIBLE NORTH OF INTERSTATE 80 AS THE SECOND UPPER WAVE MOVES OVERHEAD. SEE THE FIRE WEATHER DISCUSSION FOR MORE DETAILS ON THAT WAVE. THURSDAY AFTERNOON AND EVENING A JET STREAK MOVES OVER THE NORTHERN SIERRA FOR A BETTER SHOT AT DIURNAL CONVECTION DOWN TO THE RENO-TAHOE AREA BY EARLY EVENING. SNYDER LONG TERM...FRIDAY THROUGH TUESDAY... FEW CHANGES TO THE EXTENDED FORECAST AS MEDIUM RANGE MODELS CONTINUE TO MAINTAIN GOOD AGREEMENT WITH THE CUTOFF LOW PRESSURE OVER THE WEST COAST. MAIN CHANGE WAS TO COOL HIGH TEMPERATURES ON FRIDAY AND SATURDAY A FEW DEGREES AS THE CORE OF THE LOW MOVES OVER NORTHERN CALIFORNIA AND FAR NORTHWEST NEVADA. ON FRIDAY ISOLATED THUNDERSTORMS WILL CONTINUE IN THE NORTHERN SIERRA NORTH OF LAKE TAHOE WITH THE POSSIBILITY OF NOCTURNAL STORMS CONTINUING MAINLY NORTH OF SUSANVILLE. ON SATURDAY ISOLATED THUNDERSTORMS MAY STILL BE POSSIBLE NORTH OF SUSANVILLE AS THE LOW LIFTS OUT OF THE AREA. FRIDAY SHOULD BE THE COLDEST DAY OF THE WEEK WITH TEMPERATURES IN WESTERN NEVADA IN THE MID 80`S AND MID 70`S IN THE SIERRA. BY SUNDAY THE LOW BEGINS TO WEAKEN AND MOVE NORTH INTO OREGON AS HIGH PRESSURE REBUILDS OVER THE FOUR CORNERS. THE BEST INSTABILITY MOVES NORTH WITH THE LOW PRESSURE LEAVING ONLY A FEW CUMULUS CLOUDS ALONG THE SIERRA. BY MONDAY TEMPERATURES WILL RETURN TO NORMAL WITH WESTERN NEVADA RETURNING TO AROUND 90 DEGREES AND THE SIERRA AROUND 80. TOLBY AVIATION... CUMULUS WITH ISOLATED HIGH-BASED STORMS ARE BUILDING NORTH IN AND NEAR THE SIERRA THIS AFTERNOON. OUTFLOW WINDS TO 40-45 KTS ARE POSSIBLE AROUND STORMS WITH THE PRIMARY CIG/VSBY RESTRICTIONS EXPECTED OVER HIGHER TERRAIN WHERE HEAVIER RAIN WILL REACH THE GROUND. STILL NOT PLANNING ON MENTIONING ANY THUNDER AT KTRK/KTVL/KRNO/KMMH TERMINALS THIS EVENING AS CLOUDS ARE PUSHING EAST OF THE CREST TOWARDS THE PINE NUT RANGE (EASTERN DOUGLAS COUNTY) BEFORE THEY REACH NORTH TO HIGHWAY 50. AS FAR AS SMOKE FROM FIRES WEST OF THE SIERRA CREST, IT WILL AFFECT VSBYS THROUGH THIS EVENING IN MONO COUNTY ESPECIALLY WEST OF BRIDGEPORT AND SOUTH OF MONO LAKE. ISOLATED THUNDERSTORMS MAY PERSIST OVER AREAS NORTH OF SUSANVILLE THROUGH THE NIGHT WITH GUSTY OUTFLOW WINDS. ON WEDNESDAY, THUNDERSTORMS SHOULD BE RESTRICTED TO SOUTH OF HIGHWAY 50 AND NORTH OF SUSANVILLE AND GERLACH. SNYDER FIRE WEATHER... BIGGEST CONCERN REMAINS THUNDERSTORMS THURSDAY. UNTIL THEN, STILL EXPECT ISOLATED THUNDERSTORMS NEAR AND EAST OF THE SIERRA CREST THIS EVENING. BUILDING CUMULUS ALREADY OVER MONO COUNTY, WITH SOME NOW DEVELOPING A LITTLE FURTHER NORTH. ONLY EXPECTING A FEW STORMS BUT THEY SHOULD BE DRY WITH VERY DRY LOW LEVELS AND STORM MOTIONS NWD AROUND 20 MPH. OTHER CONCERN IS IMPRESSIVE MID/UPPER LEVEL WAVE OFF POINT CONCEPTION. FORCING AHEAD OF IT IS IMPRESSIVE AND ALREADY GETTING A FEW ISOLATED C-G STRIKES OVER THE SACRAMENTO VALLEY SHOWING THE ELEVATED INSTABILITY. THIS WILL MOVE THROUGH OVERNIGHT WITH MODELS SHOWING IMPRESSIVE FORCING AND INSTABILITY AHEAD OF THE WAVE. IT LOOKS TO PASS THROUGH NW CA AND SW OREGON AFTER 12Z SO WE WILL ONLY BE ON THE FRINGE. WILL CONTINUE WITH ISOLATED DRY THUNDERSTORMS FOR LASSEN AND PLUMAS COUNTIES NORTH OF HWY 70 TONIGHT INTO EXTREME NW NEVADA. BEST ACTION WILL BE FURTHER NORTH AND WEST. DRIER AIR AND A BIT STRONGER WEST FLOW WILL OCCUR IN THE WAKE OF THE WAVE WEDNESDAY. THEREFORE, STILL EXPECT MAIN THREAT FOR THUNDERSTORMS NORTH OF SUSANVILLE/GERLACH. MAY SEE SOME SCT COVERAGE RIGHT NEAR THE OREGON BORDER WITH HYBRID WET/DRY STORMS. IT IS A CONCERN, BUT WITH LIMITED AREA AFFECT WILL NOT ISSUE A WATCH/WARNING THERE. AS FOR THURSDAY, AN UPPER WAVE IS EXPECTED TO MOVE IN THURSDAY MORNING WITH GOOD UPPER JET SUPPORT. IN ADDITION, MID-LEVEL MOISTURE WILL INCREASE WITH THUNDERSTORMS LIKELY TO START AROUND SUNRISE. THE BEST FORCING AND MOISTURE REMAIN NORTH OF I-80 WITH SCATTERED STORMS INTO THE AFTERNOON. LOW LEVEL MOISTURE WILL ALSO INCREASE DURING THE DAY, BUT THE FAST STORM MOTIONS OF 20-25 MPH WILL LIKELY KEEP THE STORMS IN A HYBRID WET/DRY MODE. HAVE ISSUED A WATCH FOR THE ZONES NORTH OF I-80; 270, 271, 278, 453, 458. 271 MAY BE A BIT TOO WET AS WE GO FURTHER INTO THE DAY THURSDAY, BUT GIVEN THE THREAT IN THE MORNING WHEN STORMS WOULD BE DRIER, I THOUGHT IT WOULD BE PRUDENT TO ADD IT. WALLMANN && .REV WATCHES/WARNINGS/ADVISORIES... NV...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING NVZ458. FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING NVZ453. CA...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING CAZ270-271-278. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS MIAMI FL
158 AM EDT WED AUG 7 2013 .AVIATION... WITH WEAK FLOW OVER SOUTH FLORIDA, THE SEA BREEZE SHOULD BE ABLE TO DEVELOP AROUND MID DAY. UNTIL THEN, THE WEATHER SHOULD BE FAIRLY QUIET, WITH VFR CONDITIONS. ONCE THE SEA BREEZE KICKS IN AROUND MID DAY, IT WILL BEGIN TO ONCE AGAIN TRIGGER CONVECTION. HOWEVER, IT SHOULD BE MORE INLAND THAN ON THE COAST, THUS, HAVE KEPT VCTS OUT OF THE TAFS FOR ALL BUT KAPF TODAY. HOWEVER, DID PLACE VCSH AS SOME SHOWERS COULD INITIALIZE NEAR THE COAST AND MOVE INLAND BEFORE THEY DEVELOP INTO THUNDERSTORMS. WINDS TODAY WILL BE GENERALLY SOUTHEAST AROUND 10 KTS. && .PREV DISCUSSION... /ISSUED 801 PM EDT TUE AUG 6 2013/ UPDATE... ONLY ISOLATED THUNDERSTORMS REMAIN EARLY THIS EVENING ACROSS MAINLY INLAND BROWARD COUNTY AND LAKE OKEECHOBEE. THESE STORMS CONTINUE TO WEAKEN AND SHOULD DISSIPATE OVER THE NEXT FEW HOURS. WINDS SHOULD REMAIN LIGHT OVERNIGHT BEFORE TURNING MORE EASTERLY ON WEDNESDAY THROUGH THE REMAINDER OF THE WEEK. PREV DISCUSSION... /ISSUED 253 PM EDT TUE AUG 6 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... A MID/UPPER LEVEL RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHERN STATES INTO THE ATLANTIC WITH AN INVERTED TROUGH MOVING WEST ACROSS THE EASTERN BAHAMAS BENEATH THE RIDGE AXIS. AT THE SURFACE, A WEAK SURFACE TROUGH EXTENDS FROM SOUTH FLORIDA INTO THE NORTHERN BAHAMAS AND INTO THE CENTRAL ATLANTIC. THE SURFACE TROUGH IS A VERY SHALLOW FEATURE AND THIS COMBINED WITH THE UPPER TROUGH TO THE EAST AND RIDGE TO THE NORTH IS RESULTING IN VERY WEAK SURFACE PRESSURE GRADIENT BECOMING NORTH TO NORTHEAST FLOW ABOVE 5K FT. THE 12Z MFL SOUNDING CAPTURED THIS WELL AND ALSO SHOWS PWAT REMAINING AT AROUND TWO INCHES. ALL OF THIS SPELLS CONVECTIVE DEVELOPMENT MOVING OFF TO THE SOUTH AND THE HRRR HAS BEEN INDICATING THIS ALSO WITH GOOD INITIAL TIMING AND LOCATION. THE SOUNDING ALSO SHOWED MID LEVEL LAPSE RATES QUITE WEAK AT 5.8 DEGREES CELSIUS/KM AND A 500 MB TEMPERATURE OF ONLY -5.9 WHICH IS NEARLY TWO DEGREES WARMER THAN AVERAGE FOR EARLY AUGUST SO ONLY ISOLATED STRONG STORMS ARE EXPECTED THIS AFTERNOON AT BEST. THE MID LEVEL TROUGH WILL CONTINUE MOVING TO THE WEST IN THE SHORT TERM WITH ALL GLOBAL MODELS IN VERY GOOD AGREEMENT SHIFTING IT INTO THE CENTRAL BAHAMAS ON WEDNESDAY AND THE WESTERN BAHAMAS BY LATE THURSDAY. AS THE TROUGH APPROACHES SOUTH FLORIDA, THE EASTERLY FLOW WILL DEEPEN AS THE UPPER RIDGE TO THE NORTH MOVES LITTLE THROUGH THIS PERIOD. THE ATMOSPHERIC MOISTURE PROFILE WILL CHANGE LITTLE THROUGH WEDNESDAY AND WITH THE EAST FLOW DEEPENING, THE PRIMARY THREAT FOR CONVECTIVE ACTIVITY WILL TEND TO BE MORNING SHOWERS ALONG THE EAST COAST AND THEN SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING OVER THE INTERIOR DURING THE AFTERNOON AND MOVING TOWARDS THE SOUTHWEST COAST. THE STEERING WINDS ARE ONLY EXPECTED TO BE AROUND 5 MPH SO THE THREAT WILL EXIST FOR POSSIBLE LOCALLY HEAVY RAINS IN THE NAPLES AREA. THERE COULD ACTUALLY BE LESS ACTIVITY ON THURSDAY AS THE TROUGH APPROACHES WHICH PLACES SOUTH FLORIDA ON THE SUBSIDENCE SIDE. THIS TROUGH CURRENTLY SHOWS UP VERY WELL IN WATER VAPOR IMAGERY WITH STRONG SUBSIDENCE SHOWING UP TO ITS WEST. THE MODELS ALSO SHOW THE LOW MAINTAINING ITS CURRENT STRENGTH SO ANOTHER REASON THERE COULD BE LESS ACTIVITY. BY THURSDAY NIGHT, THE ATMOSPHERE WILL UNDERGO GOOD DESTABILIZATION AS THE TROUGH MOVES INTO THE STRAITS OF FLORIDA. THE GFS IS INDICATING 500 MB TEMPERATURES COOLING TO -11 SOUTHEAST OF KEY LARGO AND -10 OFF THE SOUTHEAST COAST. THE NAM IS A TAD BID SLOWER WITH THE MOVEMENT BUT STILL SHOWS THIS SAME COLD POOL ABOUT 50-100 MILES TO THE SOUTHEAST OF THE GFS POSITION. AT ANY RATE, THIS COULD SET OFF SOME IMPRESSIVE LIGHTNING DISPLAYS TO OUR SOUTHEAST THURSDAY EVENING AND NIGHT AS CONVECTIVE CELLS COULD EASILY DEVELOP OVER THE ATLANTIC WATERS WITH SUCH COLD TEMPERATURES ALOFT MOVING ACROSS THE GULF STREAM WATERS MAKING THE ENVIRONMENT VERY UNSTABLE. BUT AS ALWAYS AS WE GET OUT WITH TIME, CONFIDENCE IS LESS SO IT IS A WAIT AND SEE APPROACH. LONG TERM (FRIDAY-TUESDAY)... LATE IN THE WEEK AND INTO THE WEEKEND AND EARLY NEXT WEEK, THE TROUGH WILL CONTINUE WESTWARD INTO THE GULF OF MEXICO ALLOWING THE ATLANTIC RIDGE TO ALSO BUILD WEST. THIS WILL STABILIZE THE ATMOSPHERE ONCE AGAIN AND THE GFS IS ALSO SHOWING SIGNIFICANT DRYING TAKING PLACE WITH PWAT DROPPING WELL UNDER TWO INCHES. SO WHILE FRIDAY COULD REMAIN QUITE ACTIVE, MUCH LESS ACTIVITY IS LIKELY AS WE GET INTO THE WEEKEND AND CROSS OVER INTO NEXT WEEK. MARINE... LIGHT AND VARIABLE WIND TONIGHT WILL SLOWLY BECOME EAST BY WEDNESDAY AND THEN STRENGTHENING LATER IN THE WEEK AS THE GRADIENT TIGHTENS. THIS WILL BUILD SEAS OVER THE NEXT COUPLE OF DAYS BUT REMAIN WELL BELOW ADVISORY CRITERIA. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 78 89 80 / 30 20 20 20 FORT LAUDERDALE 90 81 90 81 / 30 20 20 20 MIAMI 91 79 89 80 / 30 20 20 20 NAPLES 92 76 93 77 / 40 30 30 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...10/CD AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS GOODLAND KS
308 AM MDT WED AUG 7 2013 .UPDATE... ISSUED AT 745 PM MDT TUE AUG 6 2013 UPDATED TO REMOVE THE CONVECTIVE WATCH AND ACCOUNT FOR DECREASING THUNDERSTORM COVERAGE ACROSS THE SOUTH AND ADDITIONAL THUNDERSTORMS MOVING ACROSS NORTHEAST COLORADO INTO FAR SOUTHWEST NEBRASKA AND FAR NORTHWEST KANSAS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 222 PM MDT TUE AUG 6 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS FEATURE. THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT. WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 308 AM MDT WED AUG 7 2013 DIFFERENCES EXIST IN THE TIMING AND CHARACTER OF SHORTWAVE THAT MOVES ACROSS THE AREA EARLY IN THE EXTENDED PERIOD. AT THE START OF THE EXTENDED...RELATIVELY COOL/DRY NORTHEASTERLY POST FRONTAL SURFACE FLOW WILL BE IN PLACE ACROSS THE AREA EARLY SATURDAY. THIS WILL TRANSITION INTO SOUTHEASTERLY SURFACE FLOW LATER IN THE DAY ON SATURDAY. ADEQUATE MOISTURE AND LOW LEVEL CONVERGENCE MAY RESULT IN SHOWERS AND THUNDERSTORMS DEVELOPING SATURDAY AFTERNOON...ESPECIALLY ACROSS THE WESTERN PORTION OF THE AREA. ADDITIONALLY...CONVECTION THAT DEVELOPS FROM ELEVATED HEATING IN THE COLORADO MAY MOVE EASTWARD REACHING WESTERN PORTIONS OF THE AREA DURING THE EVENING. THE PATTERN CHANGES LITTLE THROUGH THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK. WESTERLIES ALOFT WILL CONTINUE WITH EMBEDDED MINOR DIFFICULT TO TIME SHORTWAVE TROUGHS NECESSITATING SLIGHT TO LOW CHANCE POPS EACH DAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1148 PM MDT TUE AUG 6 2013 INITIAL CONCERNS ARE ONGOING CONVECTION TO THE WEST OF BOTH TAF SITES. GLD WILL EXPERIENCE A SHIFT IN WIND DIRECTION AND INCREASE IN SPEEDS AS A RESULT OF AN OUTFLOW BOUNDARY SHORTLY AFTER 06Z. THUNDERSTORMS SHOULD DECREASE OVER THE NEXT FEW HOURS. OTHER CONCERNS FOR GLD WAS A BRIEF REDUCTION OF VISIBILITY LAST HOUR. THIS APPEARS TO BE TEMPORARY. FURTHER REDUCTIONS ARE UNLIKELY ESPECIALLY AFTER THUNDERSTORM OUTFLOW BOUNDARY PASSES THROUGH. FOR MCCOOK...THUNDERSTORMS MAY BE IN THE VICINITY BY AROUND 08Z. SOME FOG COULD FORM AT MCK BUT NEARBY THUNDERSTORMS AND RESULTANT OUTFLOW MAY KEEP WINDS UP ENOUGH TO PREVENT THIS. TRENDS WILL BE MONITORED AND AMENDMENTS MAY BE NEEDED LATER TONIGHT. OTHERWISE...SHOWERS AND THUNDERSTORMS ARE POSSIBLE AT EITHER SITE TOMORROW AFTERNOON AND EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...LOCKHART SHORT TERM...DR LONG TERM...BRB AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
317 AM CDT Wed Aug 7 2013 ...UPDATED LONG TERM... .SYNOPSIS... ISSUED AT 1229 AM CDT WED AUG 7 2013 At 00z Wednesday a +100kt 250mb jet extended from South Dakota into the western great lakes. The right entrance region was located near central Nebraska/northern Kansas. At the 500mb level an upper level trough was located over eastern Montana and an upper level ridge axis was located across the pacific northwest. Further south over the southern plains an upper high was located near the gulf coast of Texas and an upper level low/trough moved northward out of Mexico into eastern Arizona. Convection that developed across southwest Kansas near the Colorado border around 00z Wednesday was currently moving east/southeast across south central Kansas at 05z. These storms appeared to located where the better 850mb moisture, frontogenesis, and warm air advection were occurring earlier this evening. Further north another area of convection had developed during the evening hours from northeast Colorado into western Nebraska. This a located near a surface trough of low pressure and where better moist upslope flow was present along with better mid level lapse rates. RAP also hinted at a subtle upper level wave was located in this area at 00z. && .SHORT TERM...(Today and tonight) ISSUED AT 251 AM CDT WED AUG 7 2013 The NAM, RAP, GFS were all in decent agreement this morning with moving an upper level trough across northern Kansas early this morning. Based on the 06z location of this upper wave it appears that an area of convection had developed ahead of this system based on the composite radar loop. Given this and the timing of the upper level trough will raise precipitation chances in the north to at least high chance for early this morning. Further south the chances for convection early will be less but still given weak lift forecast across southwest Kansas will keep some small pops going early today. Convection should briefly taper off as the upper level trough passes east of the area, however by the early afternoon the chances for convection will begin to improve, especially across far western and southwest Kansas where moist upslope flow is expected and better afternoon instability and 0-6km shear is forecast to be located. Convection will then increase in areal coverage as it spreads east across the remainder of western Kansas late today and overnight as the Arizona upper low/trough moves east across New Mexico. Heavy rainfall will still be an issue later today and overnight given the precipitable water content on the Dodge City soundings at 1.42 inches at 00z Wednesday. Also strong damaging winds and large hail will be possible from some these storms late today and early tonight. The flood watch currently in the effect still looks on track given several opportunities of heavy precipitation later today through Thursday. .LONG TERM...(Thursday through Tuesday) ISSUED AT 315 AM CDT WED AUG 7 2013 A cool and wet period is forecast for the area with much above average forecaster certainty for significant measurable rainfall through thursday. The synoptic set up includes an already very moist atmosphere across the central high plains, characterized by dew points in the 60s and 70s. additionally, and upper high center over the Southern Plains and Gulf region helping transport additional pacific moisture poleward. the kinematic fields will include the slow development of a Central Rockies through which will place Western Kansas under a favorable positive vorticity and warm advection region for maximum lift potential thursday. Additionally, a surface/850 mb frontal zone will air in low level frontogenesis adding to the QG component. These elements have given enough confidence to raise precipitation chances into the categorical range during the day 2 period. The slow nature of this existing wave will create a fluid forecast situation . The jet streak will still leave a broad right rear quadrant entrance region into Friday, and thunderstorm cannot be ruled out through this period as well, although the trend would be downward. During this period it is likely that a widespread one to two inches of rain will fall over the entire southwest and central Kansas region. Areas of higher rainfall perhaps in excess of 5 inches are possible based on model run totals, but with relatively low forecaster confidence with respect to coverage. From Friday and onward increased ridging along the High Plains region will create a warming trend with opportunities for severe weather producing MCS events into early next week. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1229 AM CDT WED AUG 7 2013 Models and guidance remains in decent agreement in keeping the wind easterly across western Kansas overnight and Wednesday. Boundary layer not as moist as the past few nights and with stronger winds forecast just above the surface it currently appears enough mixing will occur to prevent any significant fog/status development. latest HRRR also suggesting a similar solution. Convection over northeast Colorado will move east/southeast and currently is expected to impact mainly the Hays area around daybreak. Widespread convection will then once again be possible by later today/early tonight across all of western Kansas. && .PRELIMINARY POINT TEMPS/POPS... DDC 82 66 78 62 / 70 80 50 40 GCK 80 65 77 61 / 70 80 50 40 EHA 83 65 79 61 / 70 80 40 40 LBL 83 67 81 63 / 70 70 40 40 HYS 79 65 75 61 / 70 80 60 40 P28 85 69 81 66 / 70 80 50 40 && .DDC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066- 079-081. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...RUSSELL AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
254 AM CDT Wed Aug 7 2013 ...UPDATED SHORT TERM DISCUSSION... .SYNOPSIS... ISSUED AT 1229 AM CDT WED AUG 7 2013 At 00z Wednesday a +100kt 250mb jet extended from South Dakota into the western great lakes. The right entrance region was located near central Nebraska/northern Kansas. At the 500mb level an upper level trough was located over eastern Montana and an upper level ridge axis was located across the pacific northwest. Further south over the southern plains an upper high was located near the gulf coast of Texas and an upper level low/trough moved northward out of Mexico into eastern Arizona. Convection that developed across southwest Kansas near the Colorado border around 00z Wednesday was currently moving east/southeast across south central Kansas at 05z. These storms appeared to located where the better 850mb moisture, frontogenesis, and warm air advection were occurring earlier this evening. Further north another area of convection had developed during the evening hours from northeast Colorado into western Nebraska. This a located near a surface trough of low pressure and where better moist upslope flow was present along with better mid level lapse rates. RAP also hinted at a subtle upper level wave was located in this area at 00z. && .SHORT TERM...(Today and tonight) ISSUED AT 251 AM CDT WED AUG 7 2013 The NAM, RAP, GFS were all in decent agreement this morning with moving an upper level trough across northern Kansas early this morning. Based on the 06z location of this upper wave it appears that an area of convection had developed ahead of this system based on the composite radar loop. Given this and the timing of the upper level trough will raise precipitation chances in the north to at least high chance for early this morning. Further south the chances for convection early will be less but still given weak lift forecast across southwest Kansas will keep some small pops going early today. Convection should briefly taper off as the upper level trough passes east of the area, however by the early afternoon the chances for convection will begin to improve, especially across far western and southwest Kansas where moist upslope flow is expected and better afternoon instability and 0-6km shear is forecast to be located. Convection will then increase in areal coverage as it spreads east across the remainder of western Kansas late today and overnight as the Arizona upper low/trough moves east across New Mexico. Heavy rainfall will still be an issue later today and overnight given the precipitable water content on the Dodge City soundings at 1.42 inches at 00z Wednesday. Also strong damaging winds and large hail will be possible from some these storms late today and early tonight. The flood watch currently in the effect still looks on track given several opportunities of heavy precipitation later today through Thursday. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 320 PM CDT TUE AUG 6 2013 Not too much has changed in the extended forecast, except rain chances have increased in the Thursday time frame. 80% categorical shower and thunderstorms chances late Wednesday night and early Thursday morning will taper to 50 to 60 percent likely chances by Thursday day break, and stay about there through the day Thursday. a meandering surface front across southwestern Kansas will combine with an upper level short wave moving east across western Kansas, to bring more substantial rainfall to southwestern Kansas Thursday. The upper wave will move into central Kansas late Thursday night, and precipitation chances will taper even lower into the 40 percent range Thursday night, and diminish downward to 15 percent by Friday afternoon. Once that upper wave is to our east, another will be tracking from the west, nearly on it`s heal. Saturday will see scattered 20 to 30 percent rain chances, and low widely scattered showers and thunderstorm trend will persist into Sunday night. On Monday, chance pops will cover most all of our forecast area of southwestern Kansas, as the larger upper wave will be crossing then. Precipitation chances will shift east Monday night and Tuesday, and felt slight chances were enough for now out in the day 8 time frame. For temperatures, Thursday will start out "cool" with highs int he upper 70s across out northern 3/4ths of the forecast area, and in the lower to mid 80d along the Oklahoma border. This will mainly be due to a cold front slipping southward through our area, but also due to clouds and precipitation being plentiful. Clouds will be slow to break up and clear on Friday, so temperatures will respond to the lower 80s to middle 80s. A warming trend will ensue through Sunday, when max temps will rise into the lower to middle 90s. Max temps will remain in that 90s range Sunday through Tuesday. Minimum temperatures will range in the lower to middle 60s from Thursday through Sunday, then rise a little into the middle 60s to lower 70s Monday through Tuesday. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1229 AM CDT WED AUG 7 2013 Models and guidance remains in decent agreement in keeping the wind easterly across western Kansas overnight and Wednesday. Boundary layer not as moist as the past few nights and with stronger winds forecast just above the surface it currently appears enough mixing will occur to prevent any significant fog/status development. latest HRRR also suggesting a similar solution. Convection over northeast Colorado will move east/southeast and currently is expected to impact mainly the Hays area around daybreak. Widespread convection will then once again be possible by later today/early tonight across all of western Kansas. && .PRELIMINARY POINT TEMPS/POPS... DDC 82 66 78 62 / 70 80 50 40 GCK 80 65 77 61 / 70 80 50 40 EHA 83 65 79 61 / 70 80 40 40 LBL 83 67 81 63 / 70 70 40 40 HYS 79 65 75 61 / 70 80 60 40 P28 85 69 81 66 / 70 80 50 40 && .DDC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066- 079-081. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...BURKE AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1156 PM MDT TUE AUG 6 2013 .UPDATE... ISSUED AT 745 PM MDT TUE AUG 6 2013 UPDATED TO REMOVE THE CONVECTIVE WATCH AND ACCOUNT FOR DECREASING THUNDERSTORM COVERAGE ACROSS THE SOUTH AND ADDITIONAL THUNDERSTORMS MOVING ACROSS NORTHEAST COLORADO INTO FAR SOUTHWEST NEBRASKA AND FAR NORTHWEST KANSAS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 222 PM MDT TUE AUG 6 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS FEATURE. THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT. WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 246 PM MDT TUE AUG 6 2013 FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL WEATHER PATTERN WILL REMAIN LARGELY UNCHANGED. AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE AREA WEDNESDAY NIGHT AND SLOWLY GLIDE EASTWARD ACROSS THE AREA WITH ANOTHER ONE FOLLOWING IT OVER THE AREA THURSDAY. WITH THE MID THROUGH UPPER LEVELS NEARLY TO TOTALLY SATURATED AND THE RIGHT ENTRANCE OF THE 300MB JET OVER THE AREA AS THESE TROUGHS MOVE THROUGH...AM THINKING THERE SHOULD BE A GOOD CHANCE FOR SCATTERED TO WIDESPREAD RAINFALL DEVELOPMENT. THE BEST AREA FOR PRECIP. CHANCES LOOKS TO BE OVER THE SOUTH HALF WHERE THE BETTER FORCING AND LIFT WILL BE. PRECIP. CHANCES TAPER OFF THURSDAY NIGHT FROM WEST TO EAST AS THE UPPER LEVEL TROUGH MOVES OUT OF THE AREA AND DRIER AIR MOVES IN BEHIND IT. WEDNESDAY EVENING LOOKS TO BE THE BEST CHANCE FOR SEVERE STORM DEVELOPMENT DUE TO 0-6KM SHEAR OF 30-50KTS. HOWEVER ANY SEVERE STORMS THAT DEVELOP SHOULD REMAIN CONFINED TO THE WESTERN AND SOUTHERN FRINGES OF THE AREA WHERE THE BEST INSTABILITY WILL BE LOCATED. HEAVY RAINFALL WILL BE THE PREDOMINANT THREAT DURING THIS TIMEFRAME DUE TO STORM MOTIONS OF 5-10KTS. A FLASH FLOOD WATCH WILL LIKELY BE NEEDED FROM WEDNESDAY THROUGH THURSDAY MORNING FOR THE SOUTHERN TWO ROWS OF COUNTIES WHERE STORM COVERAGE WILL BE MOST WIDESPREAD. AFTER SOME DISCUSSION WILL HOLD OFF ISSUING THE WATCH FOR NOW TO PREVENT CONFUSION WITH ANY POTENTIAL FLOODING THREAT FROM TODAY/S STORM ACTIVITY. FOR FRIDAY THROUGH TUESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST CONUS WILL BUILD A BIT FURTHER NORTH...WITH THE NORTHERN PERIPHERY OF THE RIDGE OVER THE AREA. MULTIPLE UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE ACROSS THE AREA DURING THIS TIME CAUSING THERE TO BE PRECIP. CHANCES FOR NEARLY EVERY DAY. MEANWHILE THE WEAK FRONT THAT HAS BEEN WEST OF THE AREA WILL MOVE EAST ACROSS THE AREA DURING THE WEEKEND INTO EARLY NEXT WEEK. AS A RESULT TEMPERATURES WILL RETURN TO NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1148 PM MDT TUE AUG 6 2013 INITIAL CONCERNS ARE ONGOING CONVECTION TO THE WEST OF BOTH TAF SITES. GLD WILL EXPERIENCE A SHIFT IN WIND DIRECTION AND INCREASE IN SPEEDS AS A RESULT OF AN OUTFLOW BOUNDARY SHORTLY AFTER 06Z. THUNDERSTORMS SHOULD DECREASE OVER THE NEXT FEW HOURS. OTHER CONCERNS FOR GLD WAS A BRIEF REDUCTION OF VISIBILITY LAST HOUR. THIS APPEARS TO BE TEMPORARY. FURTHER REDUCTIONS ARE UNLIKELY ESPECIALLY AFTER THUNDERSTORM OUTFLOW BOUNDARY PASSES THROUGH. FOR MCCOOK...THUNDERSTORMS MAY BE IN THE VICINITY BY AROUND 08Z. SOME FOG COULD FORM AT MCK BUT NEARBY THUNDERSTORMS AND RESULTANT OUTFLOW MAY KEEP WINDS UP ENOUGH TO PREVENT THIS. TRENDS WILL BE MONITORED AND AMENDMENTS MAY BE NEEDED LATER TONIGHT. OTHERWISE...SHOWERS AND THUNDERSTORMS ARE POSSIBLE AT EITHER SITE TOMORROW AFTERNOON AND EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...LOCKHART SHORT TERM...DR LONG TERM...JTL AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1240 AM CDT Wed Aug 7 2013 ...UPDATED SYNOPSIS AND AVIATION... .SYNOPSIS... ISSUED AT 1229 AM CDT WED AUG 7 2013 At 00z Wednesday a +100kt 250mb jet extended from South Dakota into the western great lakes. The right entrance region was located near central Nebraska/northern Kansas. At the 500mb level an upper level trough was located over eastern Montana and an upper level ridge axis was located across the pacific northwest. Further south over the southern plains an upper high was located near the gulf coast of Texas and an upper level low/trough moved northward out of Mexico into eastern Arizona. Convection that developed across southwest Kansas near the Colorado border around 00z Wednesday was currently moving east/southeast across south central Kansas at 05z. These storms appeared to located where the better 850mb moisture, frontogenesis, and warm air advection were occurring earlier this evening. Further north another area of convection had developed during the evening hours from northeast Colorado into western Nebraska. This a located near a surface trough of low pressure and where better moist upslope flow was present along with better mid level lapse rates. RAP also hinted at a subtle upper level wave was located in this area at 00z. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 235 PM CDT TUE AUG 6 2013 The wet weather pattern continues as weak disturbances move around the periphery of an upper level high centered across Texas. The mid and lower levels of the atmosphere will be quite moist for this time of the year with PWAT values over 1.25 inches across western Kansas through the short term period. Thunderstorms are expected to form across far western Kansas this afternoon and spread eastward through the evening. Some of these storms may become severe with large hail and damaging winds being the main concern. A few other storms could form across the KS/OK border where a stationary front is located. Thunderstorm chances continue through midnight with decreasing coverage during the early morning hours. If storms train over the same location for an extended period of time, flooding could become a concern. Clouds will increase this afternoon with mostly cloudy skies expected overnight. Winds at the surface will generally be from the east to east southeast which will allow upslope flow to occur across western Kansas. With mostly cloudy skies overnight, lows tonight are expected to range from the upper 60s across west central Kansas to lower 70s across south central Kansas. Another lull in the action is expected Wednesday morning as the thunderstorms the night before moves into eastern Kansas. Meanwhile, a surface cold front is progged to move through Nebraska in the morning and into northern Kansas by the afternoon. Another round of thunderstorms are forecasted to form across eastern Colorado in the afternoon and move into western Kansas. A few of these storms could also become severe with strong winds and large hail being the main concern. Once again, if storms train over the same location for an extended period of time, flooding could become a concern. Winds will continue to be from the east with the exception of areas behind the aforementioned front where northeast winds will be observed. Cooler temperatures are expected tomorrow with highs ranging from the mid 70s across west central Kansas to mid 80s across south central Kansas. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 320 PM CDT TUE AUG 6 2013 Not too much has changed in the extended forecast, except rain chances have increased in the Thursday time frame. 80% categorical shower and thunderstorms chances late Wednesday night and early Thursday morning will taper to 50 to 60 percent likely chances by Thursday day break, and stay about there through the day Thursday. a meandering surface front across southwestern Kansas will combine with an upper level short wave moving east across western Kansas, to bring more substantial rainfall to southwestern Kansas Thursday. The upper wave will move into central Kansas late Thursday night, and precipitation chances will taper even lower into the 40 percent range Thursday night, and diminish downward to 15 percent by Friday afternoon. Once that upper wave is to our east, another will be tracking from the west, nearly on it`s heal. Saturday will see scattered 20 to 30 percent rain chances, and low widely scattered showers and thunderstorm trend will persist into Sunday night. On Monday, chance pops will cover most all of our forecast area of southwestern Kansas, as the larger upper wave will be crossing then. Precipitation chances will shift east Monday night and Tuesday, and felt slight chances were enough for now out in the day 8 time frame. For temperatures, Thursday will start out "cool" with highs int he upper 70s across out northern 3/4ths of the forecast area, and in the lower to mid 80d along the Oklahoma border. This will mainly be due to a cold front slipping southward through our area, but also due to clouds and precipitation being plentiful. Clouds will be slow to break up and clear on Friday, so temperatures will respond to the lower 80s to middle 80s. A warming trend will ensue through Sunday, when max temps will rise into the lower to middle 90s. Max temps will remain in that 90s range Sunday through Tuesday. Minimum temperatures will range in the lower to middle 60s from Thursday through Sunday, then rise a little into the middle 60s to lower 70s Monday through Tuesday. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1229 AM CDT WED AUG 7 2013 Models and guidance remains in decent agreement in keeping the wind easterly across western Kansas overnight and Wednesday. Boundary layer not as moist as the past few nights and with stronger winds forecast just above the surface it currently appears enough mixing will occur to prevent any significant fog/status development. latest HRRR also suggesting a similar solution. Convection over northeast Colorado will move east/southeast and currently is expected to impact mainly the Hays area around daybreak. Widespread convection will then once again be possible by later today/early tonight across all of western Kansas. && .PRELIMINARY POINT TEMPS/POPS... DDC 66 78 62 80 / 80 50 40 40 GCK 65 77 61 81 / 80 50 40 40 EHA 64 79 61 83 / 80 40 40 40 LBL 66 81 63 82 / 70 40 40 40 HYS 64 75 61 80 / 80 60 40 40 P28 69 81 66 82 / 80 50 40 40 && .DDC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066- 079-081. && $$ SYNOPSIS...BURGERT SHORT TERM...HOVORKA_42 LONG TERM...BURKE AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1215 AM CDT Wed Aug 7 2013 .UPDATE... ISSUED AT 1131 PM CDT TUE AUG 6 2013 STORMS ALONG THE FRONT HAVE DIMINISHED ACROSS SOUTH CENTRAL NE. DECIDED TO REDUCE POPS ACROSS THE NORTHERN COUNTIES TO SLIGHT FOR THE REMAINDER OF TONIGHT. MCS NOW MOVING ACROSS SOUTH CENTRAL KS. THE NORTHERN EDGE OF THE MCS MAY CLIP THE SOUTHERN COUNTIES OF THE CWA...SOUTH OF I-70. PW ON THE 00Z TOP SOUNDING WAS 1.98 INCHES...SO THERE MAY BE SOME HEAVY RAINFALL IF THE MCS DOES CLIP THE SOUTHERN COUNTIES. ALSO THESE AREAS HAVE RECEIVED A LOT OF RAINFALL OVER THE PAST WEEK...THUS ANY ADDITIONAL HEAVY RAINFALL WILL RESULT IN RUNOFF AND POTENTIAL FLOODING. I KEPT LIKELY POPS FOR THE EARLY MORNING HOURS ALONG AND SOUTH OF THE I-35 CORRIDOR. && .SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 319 PM CDT TUE AUG 6 2013 HRRR model seems to have predicted the location of the developing MCS across southwest Kansas, though the speed of propagation depicted by the HRRR model of this MCS looks to be about 2 to 3 hours too fast. the the northern edge of the MCS or leftover complex of thunderstorms may move east across the south central Kansas into the southern counties of the CWA after 100 AM. If the northern edge of this complex of thunderstorms actually moves across the southern counties of the CWA then there may be periods of heavy rainfall during the early morning hours generally south of an Abilene, to Ottawa, line given PW values of 1.8 inches. There may also be isolated to scattered thunderstorms developing along a cold front in south central NE that may move southeast into portions of north central and northeast Kansas after Midnight. Isolated showers and thunderstorm may develop along or just north of an outflow boundary along I-70 across central Kansas and move southeast across portions the southern counties of the CWA through the evening hours. .Short term...(This evening through Wednesday) Issued AT 319 PM CDT Tue Aug 6 2013 At 3 PM on Wednesday, a warm and moist airmass remained in place across all of Kansas. A warm front remained situated along the Kansas Oklahoma border while a weak outflow boundary remnant from early morning storms had stalled in northern Kansas. The other feature of note is a cold front moving into Nebraska from SD. Temperatures around 90 and dewpoints in the low to mid 70s were leading to MLCAPE values across much of the area up to 4000 J/KG. Upslope flow in western Kansas along with another weak short wave trough has initiated thunderstorms near the Colorado border... similar to Monday afternoon. This western KS activity is expected to build east and southeast into south central Kansas again today, but as the low level jet increases this evening expect the complex to build more northeast. The HRRR, which has performed rather well in the past few days, suggests that this convective complex will be enhanced by additional low level jet driven convection and will track from south central Kansas up the Kansas turnpike and across east central Kansas. A few of these individual storms may be strong with damaging winds possible mainly near and south of the turnpike. Heavy rain will also be likely, but the heaviest elements are expected to be progressive in nature and widespread heavy rain is not expected at this time, although isolated flooding will be possible. Additional storms may move out of Nebraska along the cold front after midnight, and could also be strong as they enter Kansas. There is the potential for multiple fronts/boundaries to be in place across the area on Wednesday, although the main cold front should also slowly sink into Kansas. These boundaries may serve as a focus for scattered storms throughout the day, but expect most areas to be dry during the daylight hours. Temperatures will be a bit cooler, but the very moist airmass will remain in place for much of the area. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 319 PM CDT TUE AUG 6 2013 Wednesday evening through Friday... Currently watching the next potent shortwave trough currently rotating over far southern Arizona at this hour. This wave will bring the highest chances for convective rainfall beginning Wednesday evening. Timing with this wave continues to slightly vary between each model run unfortunately leading to some uncertainty as to when heaviest rainfall will occur. Smaller embedded troughs ejected from the main shortwave could bring scattered showers and thunderstorms early on Wednesday evening before an mcs develops over western KS and traverses east through Kansas early Thursday. Highest chances for rainfall were emphasized mainly along and south of Interstate 70. Strong isentropic lift maximizes from 305 to 315k surfaces with a strong baroclinc zone in place suggesting widespread moderate to heavy rainfall. Precipitable water values agree with this scenario reaching over 2.25 inches...two standard deviations above normal. High rainfall rates may quickly lead to flash flooding and river flooding concerns for much of the cwa as current flash flood guidance only holds around 2 inches of rainfall in a three hour period. A flood watch will need to be considered in the upcoming shifts for this period. The main wave slowly lifts northeast Thursday evening with another possible mcs developing along and behind a cold front. GFS and ECMWF both indicate a complex developing over western Nebraska tracking southeast into northeast Kansas into Friday with precip slowly tapering off west to east as subsidence builds in the late afternoon. Temperatures were lowered a few degrees on Thursday afternoon as progged rainfall throughout the day with no cloud clearing expected should hold readings in the middle to upper 70s. Drier air entering from Nebraska Friday will clear out the stratus clouds with highs in the low 80s. Friday evening through Tuesday... Subsidence building behind the wave should bring a temporary lull in the rain Friday evening through Saturday afternoon. Run to run consistency between the GFS and ECWMF contains plenty of discrepancies but overall pattern characterizes the upper ridge over the western conus building once again with northwest flow increasing over the area Sunday. Periods of off and on showers and thunderstorms begin on Sunday afternoon and continue through Tuesday as a series of shortwave troughs translate along the edge of the ridge. High are generally in the mid to upper 80s...combined with dewpoints in the upper 60s should continue with the warm and muggy conditions. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Wednesday NIGHT) ISSUED AT 1209 AM CDT WED AUG 7 2013 A complex of storms will pass south of the TAF sites this morning, through some scattered thunderstorms may develop northward across the TAF sites after 6Z and last through sunrise. Expect VFR conditions through most of the the period. There may be isolated to scattered thunderstorms developing at the TAF sites late this afternoon and through the evening hours of Wednesday. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GARGAN SHORT TERM...BARJENBRUCH LONG TERM...BOWEN AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
240 AM EDT WED AUG 7 2013 .SYNOPSIS... ISSUED AT 240 AM EDT WED AUG 7 2013 A COLD FRONT WILL BRING STRONG TO SEVERE THUNDERSTORMS FROM EARLY THIS MORNING THROUGH EARLY AFTERNOON WITH DAMAGING WIND GUSTS BEING THE PRIMARY SEVERE WEATHER THREAT. MAINLY FAIR WEATHER WITH SEASONABLE TEMPERATURES IS ANTICIPATED LATE THIS WEEK THROUGH THE WEEKEND ALTHOUGH A COLD FRONT WILL BRING A SMALL CHANCE OF A SHOWER ON FRIDAY. && .SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON) ISSUED AT 240 AM EDT WED AUG 7 2013 OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE SEVERE WX POTENTIAL TODAY. RGNL RADAR TRENDS EARLY THIS MORNING SHOW A VERY WELL DEVELOPED MCS WITH HIGH WINDS OVER EAST CENTRAL WI AND WEST CENTRAL LAKE MI. THESE STORMS WILL MOVE INTO OUR NW FCST AREA AND POTENTIALLY BRING DAMAGING WIND GUSTS DURING THE EARLY MORNING HOURS. EXTRAPOLATION OF RADAR TRENDS CORROBORATED WITH 00Z 4KM WRF-NMM SIM Z GUIDANCE AND COLD FRONTAL TIMING SUGGESTS THAT THUNDERSTORMS ARE LIKELY TO DEVELOP ACROSS OUR AREA FROM THE EARLY MORNING HOURS TODAY THROUGH AROUND 18Z THIS AFTERNOON. STRONG TO SEVERE STORMS ARE LIKELY THIS MORNING AND EARLY AFTERNOON GIVEN SUFFICIENT MOISTURE... LIFT FROM THE FRONT AND WEAK TO POTENTIALLY MODERATE INSTABILITY. 0-6KM BULK SHEAR VALUES OF 35-40 KTS ARE ALSO FAVORABLE FOR STRONG TO SEVERE STORMS FROM EARLY THIS MORNING THROUGH AROUND TO SHORTLY AFTER MIDDAY. DAMAGING WIND GUSTS ARE THE PRIMARY SVR WX THREAT. THE REMAINDER OF THE SHORT TERM FCST PERIOD LOOKS TRANQUIL AS A HIGH PRESSURE RIDGE BUILDS IN TONIGHT THROUGH TOMORROW. ANOTHER COLD FRONT WILL MOVE THROUGH OUR AREA ON FRIDAY BRINGING A REINFORCING SHOT OF COOLER AIR AND A SLIGHT CHC OF A SHOWER OR STORM. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 245 AM EDT WED AUG 7 2013 NO IMPACT WEATHER IN THE EXTENDED AS COOL CANADIAN SURFACE HIGH IS IN CONTROL THROUGH THE WEEKEND. A FEW SHOWERS ARE POSSIBLE EARLY NEXT WEEK AS ANOTHER REINFORCING COLD FRONT MOVES THROUGH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1136 PM EDT TUE AUG 6 2013 THE MAIN QUESTION IS THE CONVECTION OVER EASTERN MINNESOTA AND WESTERN WISCONSIN... CAN IT REACH SOUTHWEST LOWER MICHIGAN BEFORE DISSIPATING? THE HRRR CONTINUES TO SLOW DOWN THE ARRIVAL TIME OF THE CONVECTION INTO SOUTHWEST MICHIGAN. USING THE TIMING TOOL SEVERAL TIME I FIND THE SAME TREND... EVEN WITH THE 45 KNOT SPEED OF THE CONVECTION... IT IS SLOWER EACH TIME I CHECK. AS OF 0330Z IT NOW SUGGESTS MKG AROUND 10Z AND GRR AROUND 11Z AND 12Z FOR AZO AND BTL. SO I SLOWED THE TIMING IN THE TAFS. THE CONVECTION ON THE COLD FRONT SHOULD STILL DEVELOP EAST OF US-131 EARLY TO MID AFTERNOON. IT MAY IMPACT LAN AND JXN MORE SO THAN AZO AND BTL EVEN SO I KEPT THE VCTS IN THOSE TAF SITES... AZO...BTL...LAN AND JXN JUST IN CASE. && .MARINE... ISSUED AT 240 AM EDT WED AUG 7 2013 WINDS WILL VEER TO THE WEST THEN NORTHWEST TO NORTH TODAY BEHIND THE COLD FRONT AND CAUSE WAVE HEIGHTS TO RAMP UP SOMEWHAT. HOWEVER WINDS AND WAVE HEIGHTS SHOULD REMAIN BELOW SCA CRITERIA. THUNDERSTORMS WITH HIGH WINDS WILL POSE A HAZARD TO MARINERS THIS MORNING. && .HYDROLOGY... ISSUED AT 240 AM EDT WED AUG 7 2013 NO SIGNIFICANT HYDRO ISSUES ANTICIPATED WITH RAINFALL TODAY NOT EXPECTED TO BE VERY HEAVY IN TERMS OF BASIN AVERAGE QPF AMOUNTS... THOUGH HEAVIEST STORMS COULD CERTAINLY PRODUCE LOCALLY HEAVY RAINFALL AND SOME URBAN AND SMALL STREAM TYPE FLOODING ISSUES THIS MORNING AND EARLY AFTERNOON. BASIN AVERAGE QPF AMOUNTS OF ONLY AROUND A QUARTER TO THREE QUARTERS OF AN INCH ARE EXPECTED BUT HEAVIEST STORMS COULD EASILY PRODUCE LOCALLY HIGHER AMOUNTS OF AN INCH OR TWO. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...OSTUNO AVIATION...WDM HYDROLOGY...LAURENS MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1143 PM CDT Tue Aug 6 2013 .UPDATE... Issued at 945 PM CDT TUE AUG 6 2013 Have made some minor changes to PoPs to account for trends with convection across northern Missouri and convection over southern Kansas possibly moving in later tonight. Also, confidence is increasing that we`ll see thunderstorms develop between 10pm and midnight in our far southern zones. ACCAS was evident on visible imagery before sunset and on IR imagery before the cirrus shield from the Kansas storms obscured things. Still, an arc of ACCAS can be inferred from southern Missouri to around Harrisonville. The HRRR, our local WRF and the RAP all generate storms in this arc within the next few hours. Across our north, thunderstorms have developed ahead of the main front, possible on or near a residual outflow boundary. Instability will remain moderate to strong overnight and shear may be enough for some storm organization. But updrafts have had a hard time persisting for very long to utilize the shear. Overall, the initial updrafts are more likely to produce marginally severe hail tonight. Otherwise the greatest threat should be from heavy rain and localized, especially if storms in our south develop and track over areas that saw rain late last night/early this morning. Localized strong to damaging winds may also continue into the night with any of the strongest storms. && .SHORT TERM...(This Evening through Wednesday Night) Issued at 331 PM CDT TUE AUG 6 2013 Tonight: Another potentially active period is anticipated late this evening into the overnight hours for much of the forecast area. Several boundaries are noted across the region as of early this afternoon, all that may potentially contribute as a focus for convective development during the next 12 hours. An outflow boundary from earlier convection over Nebraska and Iowa, identified by surface observations and transient convective towers, has pushed southward into northern Missouri, approximately 70 miles north of the Interstate 70 corridor. Second, a poorly defined thermal boundary that has been a primary driving force for several days remains across southeast Kansas into southern Missouri. Lastly, a cold front over the Nebraska Panhandle into southeast South Dakota continues a steady southward push. These boundaries will be the main focus for additional showers and thunderstorm development across the forecast area this evening and overnight. Upslope flow over the High Plains will once again help promote scattered thunderstorms over western Kansas this afternoon. This activity will likely evolve into a complex of thunderstorms and move eastward during the evening. While the initial activity may gradually weaken, a strengthening 30kt low-level jet will induce additional convection along and north of the aforementioned boundaries across the CWA. This overall philosophy is supported by recent convective-resolving and operational models, and is similar to last nights evolution. Additional thunderstorms may develop along the cold front over Nebraska and Iowa, with a complex of thunderstorms moving towards northern Missouri. Models have struggled with consistently developing activity in this region, and the lack of a cumulus field along the boundary remains. Nevertheless, sufficient forcing should allow for thunderstorms to develop in this region, but uncertainty remains to how far south the activity will persist. Overall, uncertainty exists with current forecast with regards to timing and coverage for tonight, but enough evidence supports scattered to occasionally widespread convection over portions of the CWA overnight. With high precipitable water values and moderate instability, the most robust convection will be capable of heavy rainfall and localized damaging wind gusts. While widespread flooding concerns are not expected at this stage, localized flooding in some creeks or streams cannot be ruled out. Wednesday/Wednesday night: The majority of moderate/heavy rainfall should be in the process of exiting the CWA around sunrise Wed. The cold front will push through the forecast area no later than mid-morning Wednesday, with northerly winds occurring behind the boundary. Some drier air will advect into the northern portion of the CWA by Wed evening, while a humid airmass should remain elsewhere. Scattered showers or weak thunderstorms will be possible north of the frontal boundary during the daylight hours, mainly south of Interstate 70. A much more substantial chance for rainfall is expected Wednesday night into Thursday morning, mainly for areas along and south of Interstate 70. Here, embedded waves within the upper low and increasing isentropic ascent should lead to widespread convective development. Areas of heavy rainfall will be possible, and depending on tonights convective episode, concern may increase for flooding late Wed night into Thursday as grounds become saturated. More specifics will be realized in subsequent forecasts as details on frontal position, wave timing, and previous convective evolution becomes known. .LONG TERM...(Thursday through Tuesday) Issued at 331 PM CDT TUE AUG 6 2013 Long term forecast will remain focused on surface boundary across the region and numerous short wave troughs moving through the flow providing a chance for precipitation through much of the period. Hudson Bay low will begin to quickly translate eastward across the northern Great Lakes region as a shortwave trough rounds the southern edge of a newly developing region of low pressure in this same area. General northwest flow pattern across the central US will quickly begin to break down as a region of low pressure moves out of Baja California and into the Four Corners region. The trough will continue to move eastward across the Rockies and out onto the Plains by the end of the week. As this system nears the region...it will interact with a quasi-stationary surface boundary that will be positioned across the Central Plains. Depending on where this boundary eventually positions itself will decide where main convective activity will likely develop. Current long-range models indicate that there is the potential for storms to redevelop over the same general region through much of the period. With precipitable water values progged to be 1.5 to 2 inches across many areas, expect heavy rain to develop leading to potential flooding issues in these locations. By early next week, models begin to diverge with the EC rebuilding a ridge over the Rockies and keeping more of a pronounced northwest flow component while the GFS develops a broader ridge with more of a zonal component to the flow over the CWA. Both models bring numerous shortwave troughs across the region, but timing of these features remain uncertain and will effect precipitation chances. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday Night) Issued at 1144 PM CDT TUE AUG 6 2013 Models continue to indicate an area of thunderstorms over south central Kansas will move to the east through the night with an arc of thunderstorms developing from southern Missouri to the south side of the Kansas City metro. Latest radar returns show storms developing in the vicinity of the Lake of the Ozarks, near to where an ACCAS field has been evident all night. This should eventually arc back to the west and impact the south KC metro. Have maintained VCTS in the TAFs because for now, the greatest probabilities for storms appear to the south of the terminals. However some storms may venture further north but confidence is higher that greater impacts will be felt south of the terminals. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ UPDATE...CDB SHORT TERM...Blair LONG TERM...PMM AVIATION...CDB
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1018 PM MDT TUE AUG 6 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY... UPDATE...A FRONT CONTINUES TO SPLIT THE REGION IN TWO PARTS. NORTH OF THE FRONT THUNDERSTORMS DEVELOPED THIS AFTERNOON AND HAVE SINCE PUSHED INTO NORTH DAKOTA. LOOKING FOR A FAIRLY QUIET REMAINDER OF THE EVENING. UPDATED FORECAST TO REFLECT THE DOWNWARD TREND IN THE COVERAGE OF THE CONVECTIVE SHOWERS AND THUNDERSTORMS FOR THE NIGHT TIME HOURS. PROTON NORTHWESTERLY FLOW ALOFT CONTINUES THROUGH THURSDAY. WEATHER FOR THE NORTHERN CONUS IS DOMINATED BY A LARGE UPPER LOW OVER NORTH CENTRAL CANADA. AS THIS LOW SPINS AND MAKES SLOW PROGRESS EASTWARD OVER THE NEXT FEW DAYS...PERIODIC SHORTWAVE DISTURBANCES IN THE FLOW AROUND THE LOW PASS OVER THE MONTANA AREA. THESE DISTURBANCES BRING SUPPORT FOR SHOWERS AND THUNDERSTORMS. SHOWER ACTIVITY MOSTLY OCCURS IN THE AFTERNOONS AS DAYTIME HEATING OF THE RELATIVELY MOIST BOUNDARY LAYER CREATES CONVECTIVE INSTABILITY WHICH COMBINES WITH MODEST UPPER LEVEL FORCING FROM SHORTWAVE ACTIVITY. CURRENTLY..SOME NON-SEVERE SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED WITH THE PASSAGE OF A SHORTWAVE TONIGHT WITH A WEAKER ONE DUE LATE WEDNESDAY. THURSDAY AFTERNOON HAS A LOWER CHANCE OF CONVECTIVE ACTIVITY AS THE GFS AND NAM HAVE THE CANADA LOW BY THAT TIME FAR ENOUGH EASTWARD TO ALLOW SOME BUILDING OF HIGH PRESSURE OVER THE ROCKIES. FOR TONIGHT...THE HRRR MODEL SEEMS TO HAVE A REASONABLE HANDLE ON DEVELOPMENT FOLLOWING THE LOWER RESOLUTION MODELS IN PRODUCING AN AREA OF SHOWERS OVER THE NORTHEAST 2/3RDS OF THE CWA...WHICH DIES OUT AROUND 9PM. STRENGTH OF CONVECTION IS EXPECTED TO BE MODEST...THOUGH SOME THUNDERSTORMS WILL OCCUR...AS BOUNDARY LAYER INSTABILITY IS WEAK WITH LESS THAN 1000 J/KG OF MLCAPE AT MOST...WHICH RAPIDLY DECLINES AFTER 6PM AS THE SURFACE COOLS DIURNALLY. TEMPERATURES ARE EXPECTED TO BE MILD THROUGH THURSDAY DUE TO CLOUD COVER AND LIMITED THICKNESSES IN THE SOUTHWEST QUADRANT OF THE CANADA LOW. THERE IS ALSO A LACK OF WELL-DEFINED SURFACE FEATURES THAT WOULD LEAD TO STRONG WINDS. CURRENT SURFACE LOW EXITING THE DAKOTAS HAS KEPT NORTHWESTERLY SURFACE WINDS IN PLACE. THESE WINDS WILL BECOME LIGHTER TONIGHT AND WEDNESDAY...AND THEN MORE EASTERLY ON THURSDAY AS A THERMAL SURFACE LOW DEVELOPS OVER THE ROCKIES. MARTIN .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... THE EXTENDED PERIOD BEGINS THURSDAY NIGHT WITH HIGH PRESSURE AND A HEAT DOME OVER THE SOUTHWESTERN DESERT...WITH AN UPPER RIDGE EXTENDING NORTH ALL THE WAY UP INTO THE PACIFIC NORTHWEST. THE CLOSED UPPER LEVEL CANADIAN LOW WILL BE RETREATING EAST INTO ONTARIO...LEAVING BEHIND IN ITS WAKE ANOTHER...BUT WEAKER...TROUGH OVER THE PRAIRIE PROVINCES. THIS PATTERN WILL MAINTAIN OUR NORTHWEST FLOW ALOFT AND THE STATIONARY BOUNDARY ACROSS NORTHEAST MONTANA THROUGH MOST OF THE WEEKEND. THIS FLOW WILL NOT BE CLEAN...RESULTING IN OCCASIONAL SHORT PERIODS OF RAIN SHOWERS OR THUNDERSTORMS. THEN AS THE RIDGE ATTEMPTS TO MOVE EAST A COUPLE OF LOWS IN THE PAC-NW AND WESTERN CANADA SEND MOISTURE OVER THE DIVIDE. THIS MOISTURE AND MORE DISTURBANCES WILL TEND TO KNOCK DOWN THE RIDGE AND CONTINUE TO PRODUCE RAIN SHOWERS AND THUNDERSTORMS INTO NEXT WEEK. GUIDANCE SUGGEST WARMING TO ABOVE NORMAL...BUT THE PATTERN MIGHT RESIST THAT GUIDANCE TREND. FEW SIGNIFICANT CHANGES WERE NEEDED. SCT PREVIOUS DISCUSSION... FORECAST THROUGH THE END OF THE WEEK WILL BE INFLUENCED BY THE LINGERING EFFECTS OF THE STRONG HUDSON BAY LOW. UPPER RIDGE BUILDING NORTH ALONG THE ROCKIES WILL BE THE MAIN PLAYER FOR EARLY NEXT WEEK. MODELS SLIPPING OUT OF AGREEMENT REGARDING THE HUDSON BAY LOW AFTER IT DROPS INTO CENTRAL MANITOBA. ECMWF MOVES IT EAST FASTER THEN THE GFS BUT LEAVES A PORTION BEHIND IN SASKATCHEWAN THURSDAY NIGHT. EC CURRENTLY NOT INDICATING MUCH INFLUENCE ON THE SENSIBLE WEATHER WITH THIS FEATURE BUT THAT COULD CHANGE. NORTHWEST FLOW INTO EASTERN MONTANA ALONG WITH CANADIAN HIGH PUSHING INTO THE NORTHERN PLAINS SUGGEST A SHORT PERIOD OF DRIER WEATHER BUT AS SHORTWAVES BEGIN EJECTING OUT OF THE TROF ALONG THE WEST COAST AND THROUGH THE NORTHERN ROCKIES RIDGE...WILL SEE A RETURN OF THUNDERSTORM CHANCES. AFTER A COOL START TO THE EXTENDED PERIOD WITH THE PROXIMITY OF THE HUDSON BAY LOW...TEMPERATURES WILL WARM THROUGH THE WEEKEND AS UPPER RIDGE PUSHES OUT INTO THE NORTHERN PLAINS. EBERT && .AVIATION... VFR TO MVFR CEILINGS DURING THE MORNING. WITH THE PASSAGE OF THUNDERSTORMS EARLIER THIS EVENING EXCESSIVE MOISTURE APPEARS TO BE ADEQUATE ENOUGH TO GENERATE A LOW CEILING ACROSS THE NORTHERN AND EASTERN MOST TERMINALS WITH KOLF VERY LIKELY TO SEE FUEL LOADING CONDITIONS. THE OTHER THREE TERMINALS ARE CLOSE TO MVFR AND COULD ALSO EXPERIENCE THESE CONDITIONS BUT ARE NOT YET PLACED INTO THE TAFS. WILL HAVE TO MONITOR THE GOES FOG/IR SATELLITE PRODUCT ACROSS THE REGION THIS EVENING AND AMEND AS NEEDED. AN UPPER LEVEL RIDGE WEST OF THE DIVIDE AND A STRONG LOW PRESSURE SYSTEM OVER MANITOBA WILL MAINTAIN NORTHWEST FLOW ALOFT FOR NORTHEAST MONTANA. THESE WEATHER SYSTEMS HAVE PLACED A STATIONARY FRONT ACROSS ROUGHLY THE LOCAL TERMINALS THAT WILL BE THE FOCUS OF INTERMITTENT RAIN SHOWERS AND GENERAL THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING. BRIEF PERIODS OF LESS THAN VFR CONDITIONS ARE POSSIBLE WITH ANY THUNDERSTORMS THAT DEVELOP. ISOLATED FOG AND LOW STRATUS IN THE EVENINGS COULD ALSO BE POSSIBLE AS A BY PRODUCT BUT CONFIDENCE IS NOT YET HIGH ENOUGH TO PLACE IN THE TAFS. WIND WILL BECOME LIGHT AND VARIABLE TONIGHT INTO WEDNESDAY EVENING. GAH && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1228 AM CDT WED AUG 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE THROUGH TONIGHT SPARKING TSTMS...SOME SEVERE. A SUBTROPICAL DISTURBANCE...CURRENTLY ACROSS AZ...UT AND WRN COLO WILL LIFT THROUGH THE SRN PTN OF FCST AREA WEDNESDAY AND THURSDAY PRODUCING RAIN...MAINLY SOUTH OF THE INTERSTATE 80. THE UPPER LEVEL LOW ACROSS HUDSON BAY WILL MIGRATE INTO THE CANADIAN MARITIMES THIS WEEKEND. IN DOING SO...A LOBE OF UPPER LEVEL ENERGY COULD PRODUCE THUNDERSTORMS ACROSS NRN NEB SATURDAY NIGHT AND SUNDAY. && .UPDATE... ISSUED AT 754 PM CDT TUE AUG 6 2013 GIVEN THAT THE HRRR MODEL IS PLUGGING SWRN NEB WITH A SQUALL LINE THIS EVENING AND THAT WFO CYS IS ISSUING WARNINGS FOR THE PANHANDLE...POPS HAVE BEEN RAISED TO AROUND 50 PERCENT AND SEVERE WORDING HAS BEEN ADDED UNTIL MIDNIGHT. THE 23Z HRRR CONTINUES TO FLOG SWRN NEB WITH STRONG TO PERHAPS SEVERE STORMS. THE CONVECTIVE COMPLEX SHOULD EXIT THE FCST AREA BY AROUND 05Z THIS EVENING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 335 PM CDT TUE AUG 6 2013 TONIGHT AND WEDNESDAY...CONDITIONS FAIRLY UNSTABLE ACROSS SOUTHWEST INTO CENTRAL NEBRASKA...AND SCATTERED THUNDERSTORMS ARE STILL POSSIBLE. A COLD FRONT IS CURRENTLY MOVING SOUTH INTO NORTHERN NEBRASKA...WITH AN OLD OUTFLOW BOUNDARY NEARLY STATIONARY ACROSS SOUTHWEST NEBRASKA. THESE FEATURES COULD SERVE AS A FOCUS FOR THUNDERSTORM INITIATION YET THIS AFTERNOON. OTHER STORMS DEVELOPING ACROSS EASTERN WYOMING ARE EXPECTED TO MOVE EAST AND SOUTHEAST AND MAY MOVE INTO SOUTHWEST NEBRASKA LATER THIS EVENING. COVERAGE OF ANY STORM ACTIVITY IS EXPECTED TO REMAIN WIDELY SCATTERED AS OVERALL FORCING IS FAIRLY WEAK...AND NO REAL DEFINED UPPER LEVEL DISTURBANCE IS PRESENT. WILL KEEP POPS AT 30 PERCENT OR LESS TONIGHT DUE TO THESE FACTORS. A SUB TROPICAL DISTURBANCE WILL APPROACH THE AREA FROM THE SOUTHWEST CONUS WEDNESDAY...BUT CURRENT INDICATIONS ARE THAT THE MORE SIGNIFICANT RAIN FROM THIS SYSTEM WILL REMAIN TO OUR SOUTH AND WEST DURING THE DAY WEDNESDAY. COOLER CONDITIONS ARE EXPECTED FOR WEDNESDAY IN THE WAKE OF THE COLD FRONT AND WITH THE INCREASED CLOUD COVER FROM THE SUB TROPICAL DISTURBANCE. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 335 PM CDT TUE AUG 6 2013 WEDNESDAY NIGHT THROUGH FRIDAY... ALL EYES ARE ON THE SUBTROPICAL DISTURBANCE CURRENTLY ACROSS AZ/SRN UT/SWRN COLO. THE MODEL CONSENSUS TAKES THIS DISTURBANCE THROUGH NERN COLO/SWRN NEB/NWRN KS WEDNESDAY NIGHT AND THURSDAY. A CLOSED 700MB LOW FORMS BRIEFLY WEDNESDAY NIGHT AND THEN OPENS UP IN A POSITIVE FASHION THURSDAY. THUS IT WOULD APPEAR MOST OF THE RAIN WILL FALL ON THE FORWARD SIDE OF THE DISTURBANCE WEDNESDAY NIGHT AND THURSDAY. THE HPC...GEM...GFS...NAM AND ECM FCSTS WERE BLENDED FOR THE QPF FORECAST WHICH PRODUCES 1/2 TO 1 INCH OF RAIN ALONG AND SOUTH OF INTERSTATE 80. POPS ARE STILL LIMITED TO 40 PERCENT GIVEN THE TIMING AND TRACK UNCERTAINTIES OF A SYSTEM ROTATING NORTH AND EAST AROUND A SUBTROPICAL HIGH. THE MODELS DO SHOW A COLD FRONT APPROACHING NCNTL NEB LATE THURSDAY AFTN WHICH COULD ADD FOCUS TO THE RAIN EVENT. K-INDICES ARE OPERATING IN THE 30-35C RANGE. THE MODELS SHOW SOME CLEARING THURSDAY AFTN WHICH WOULD ALLOW TEMPS TO RISE INTO THE 70S. FOR FRIDAY...THE NAM...ECM AND GEM SHOW SOME AFTN TSTM ACTIVITY DEVELOPING OFF THE LARAMIE RANGE WHICH COULD DRIFT INTO WRN NEB LATE IN THE AFTERNOON. TEMPERATURES SHOULD RISE INTO THE UPPER 70S TO LOWER 80S. OTHERWISE FRIDAYS FORECAST IS UNEVENTFUL. THE NAM SHOWED STORMS FIRING OFF THE THE BACK HILLS THURSDAY AS THE COLD MOVES THROUGH. THESE STORMS...IF THEY DEVELOP...WOULD MOVE SOUTHEAST INTO NCNTL NEB LATE IN THE AFTN. FRIDAY NIGHT THROUGH TUESDAY...RAIN CHANCES PERK UP SATURDAY NIGHT AND SUNDAY AS A REINFORCING COLD FRONT DROPS THROUGH THE NRN PLAINS AND INTO NCNTL NEB. THE GEM...GFS AND ECM ARE IN GOOD AGREEMENT TAKING A LOBE OF ENERGY THRU THE NRN PLAINS AS THE HUDSON BAY LOW KICKS OUT INTO THE CANADIAN MARITIMES. MOST OF THIS ENERGY AND RAINFALL TRACK THROUGH SD SO JUST NRN NEB PICKS UP A 1/4 INCH OR SO RAINFALL. THE REST OF THE FCST IS JUST ISOLATED POPS. THE 300MB JET MAX SWINGS EAST FOCUSING THE BEST SUPPORT FOR RAINFALL INTO THE OHIO VALLEY. FARTHER WEST...A BELT OF STRONG WINDS ALOFT WILL CONTINUE ACROSS KS AND COLO. THIS COULD SUPPORT ISOLATED DIURNALLY DRIVEN TSTMS ACROSS WRN/NCNTL NEB. IT LOOKS LIKE THE SUBTROPICAL HIGH SHIFTS EAST INTO TEXAS A BIT AND TAKES THE BEST MOISTURE THRU THE MID SOUTH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1230 AM CDT WED AUG 7 2013 ONGOING CONVECTION ACROSS SOUTHWESTERN NEBRASKA...MAY IMPACT THE KLBF TERMINAL VICINITY OVER THE NEXT COUPLE OF HOURS. ATTM...THIS ACTIVITY IS EXPECTED TO REMAIN JUST OFF TO THE SOUTHWEST OF THE KLBF TERMINAL. FOR THE REMAINDER OF TONIGHT AND WEDNESDAY...EXPECT SCATTERED TO BROKEN CLOUDINESS ACROSS WESTERN AND SOUTHWESTERN NEBRASKA WITH CIGS GENERALLY RANGING FROM 10000 TO 25000 FT AGL. FOR THE KVTN TERMINAL...SCATTERED TO BROKEN CIGS OF 25000 FT AGL ARE EXPECTED OVER THE NEXT 24 HRS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CDC SHORT TERM...TAYLOR LONG TERM...CDC AVIATION...CLB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
754 PM CDT TUE AUG 6 2013 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE THROUGH TONIGHT SPARKING TSTMS...SOME SEVERE. A SUBTROPICAL DISTURBANCE...CURRENTLY ACROSS AZ...UT AND WRN COLO WILL LIFT THROUGH THE SRN PTN OF FCST AREA WEDNESDAY AND THURSDAY PRODUCING RAIN...MAINLY SOUTH OF THE INTERSTATE 80. THE UPPER LEVEL LOW ACROSS HUDSON BAY WILL MIGRATE INTO THE CANADIAN MARITIMES THIS WEEKEND. IN DOING SO...A LOBE OF UPPER LEVEL ENERGY COULD PRODUCE THUNDERSTORMS ACROSS NRN NEB SATURDAY NIGHT AND SUNDAY. && .UPDATE... ISSUED AT 754 PM CDT TUE AUG 6 2013 GIVEN THAT THE HRRR MODEL IS PLUGGING SWRN NEB WITH A SQUALL LINE THIS EVENING AND THAT WFO CYS IS ISSUING WARNINGS FOR THE PANHANDLE...POPS HAVE BEEN RAISED TO AROUND 50 PERCENT AND SEVERE WORDING HAS BEEN ADDED UNTIL MIDNIGHT. THE 23Z HRRR CONTINUES TO FLOG SWRN NEB WITH STRONG TO PERHAPS SEVERE STORMS. THE CONVECTIVE COMPLEX SHOULD EXIT THE FCST AREA BY AROUND 05Z THIS EVENING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 335 PM CDT TUE AUG 6 2013 TONIGHT AND WEDNESDAY...CONDITIONS FAIRLY UNSTABLE ACROSS SOUTHWEST INTO CENTRAL NEBRASKA...AND SCATTERED THUNDERSTORMS ARE STILL POSSIBLE. A COLD FRONT IS CURRENTLY MOVING SOUTH INTO NORTHERN NEBRASKA...WITH AN OLD OUTFLOW BOUNDARY NEARLY STATIONARY ACROSS SOUTHWEST NEBRASKA. THESE FEATURES COULD SERVE AS A FOCUS FOR THUNDERSTORM INITIATION YET THIS AFTERNOON. OTHER STORMS DEVELOPING ACROSS EASTERN WYOMING ARE EXPECTED TO MOVE EAST AND SOUTHEAST AND MAY MOVE INTO SOUTHWEST NEBRASKA LATER THIS EVENING. COVERAGE OF ANY STORM ACTIVITY IS EXPECTED TO REMAIN WIDELY SCATTERED AS OVERALL FORCING IS FAIRLY WEAK...AND NO REAL DEFINED UPPER LEVEL DISTURBANCE IS PRESENT. WILL KEEP POPS AT 30 PERCENT OR LESS TONIGHT DUE TO THESE FACTORS. A SUB TROPICAL DISTURBANCE WILL APPROACH THE AREA FROM THE SOUTHWEST CONUS WEDNESDAY...BUT CURRENT INDICATIONS ARE THAT THE MORE SIGNIFICANT RAIN FROM THIS SYSTEM WILL REMAIN TO OUR SOUTH AND WEST DURING THE DAY WEDNESDAY. COOLER CONDITIONS ARE EXPECTED FOR WEDNESDAY IN THE WAKE OF THE COLD FRONT AND WITH THE INCREASED CLOUD COVER FROM THE SUB TROPICAL DISTURBANCE. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 335 PM CDT TUE AUG 6 2013 WEDNESDAY NIGHT THROUGH FRIDAY... ALL EYES ARE ON THE SUBTROPICAL DISTURBANCE CURRENTLY ACROSS AZ/SRN UT/SWRN COLO. THE MODEL CONSENSUS TAKES THIS DISTURBANCE THROUGH NERN COLO/SWRN NEB/NWRN KS WEDNESDAY NIGHT AND THURSDAY. A CLOSED 700MB LOW FORMS BRIEFLY WEDNESDAY NIGHT AND THEN OPENS UP IN A POSITIVE FASHION THURSDAY. THUS IT WOULD APPEAR MOST OF THE RAIN WILL FALL ON THE FORWARD SIDE OF THE DISTURBANCE WEDNESDAY NIGHT AND THURSDAY. THE HPC...GEM...GFS...NAM AND ECM FCSTS WERE BLENDED FOR THE QPF FORECAST WHICH PRODUCES 1/2 TO 1 INCH OF RAIN ALONG AND SOUTH OF INTERSTATE 80. POPS ARE STILL LIMITED TO 40 PERCENT GIVEN THE TIMING AND TRACK UNCERTAINTIES OF A SYSTEM ROTATING NORTH AND EAST AROUND A SUBTROPICAL HIGH. THE MODELS DO SHOW A COLD FRONT APPROACHING NCNTL NEB LATE THURSDAY AFTN WHICH COULD ADD FOCUS TO THE RAIN EVENT. K-INDICES ARE OPERATING IN THE 30-35C RANGE. THE MODELS SHOW SOME CLEARING THURSDAY AFTN WHICH WOULD ALLOW TEMPS TO RISE INTO THE 70S. FOR FRIDAY...THE NAM...ECM AND GEM SHOW SOME AFTN TSTM ACTIVITY DEVELOPING OFF THE LARAMIE RANGE WHICH COULD DRIFT INTO WRN NEB LATE IN THE AFTERNOON. TEMPERATURES SHOULD RISE INTO THE UPPER 70S TO LOWER 80S. OTHERWISE FRIDAYS FORECAST IS UNEVENTFUL. THE NAM SHOWED STORMS FIRING OFF THE THE BACK HILLS THURSDAY AS THE COLD MOVES THROUGH. THESE STORMS...IF THEY DEVELOP...WOULD MOVE SOUTHEAST INTO NCNTL NEB LATE IN THE AFTN. FRIDAY NIGHT THROUGH TUESDAY...RAIN CHANCES PERK UP SATURDAY NIGHT AND SUNDAY AS A REINFORCING COLD FRONT DROPS THROUGH THE NRN PLAINS AND INTO NCNTL NEB. THE GEM...GFS AND ECM ARE IN GOOD AGREEMENT TAKING A LOBE OF ENERGY THRU THE NRN PLAINS AS THE HUDSON BAY LOW KICKS OUT INTO THE CANADIAN MARITIMES. MOST OF THIS ENERGY AND RAINFALL TRACK THROUGH SD SO JUST NRN NEB PICKS UP A 1/4 INCH OR SO RAINFALL. THE REST OF THE FCST IS JUST ISOLATED POPS. THE 300MB JET MAX SWINGS EAST FOCUSING THE BEST SUPPORT FOR RAINFALL INTO THE OHIO VALLEY. FARTHER WEST...A BELT OF STRONG WINDS ALOFT WILL CONTINUE ACROSS KS AND COLO. THIS COULD SUPPORT ISOLATED DIURNALLY DRIVEN TSTMS ACROSS WRN/NCNTL NEB. IT LOOKS LIKE THE SUBTROPICAL HIGH SHIFTS EAST INTO TEXAS A BIT AND TAKES THE BEST MOISTURE THRU THE MID SOUTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 637 PM CDT TUE AUG 6 2013 THE HRRR IS SENDING A SQUALL LINE THROUGH SWRN NEB THIS EVENING. THE MODEL SHOWS IT COULD AFFECT KLBF BUT THE MODEL TENDS TO OVERDO COVERAGE. THUS THE BEST FORECAST WOULD BE FOR VCTS AT KLBF THIS EVENING UNTIL WE ACERTAIN THE TRACK OF THIS SQUALL LINE. OTHERWISE VFR IS EXPECTED THIS EVENING. RAIN AND PERHAPS THUNDER IS EXPECTED WEDNESDAY ACROSS SWRN AND SCNTL NEB...MAINLY ALONG AND SOUTH OF I-80. SOME OF THE MODELS ARE FAST. SO WE ARE PLANNING ON VFR AT KLBF AND KVTN UNTIL WE ASCERTAIN THE TIMING AND EXPECTED FLIGHT CATEGORIES. GIVEN THE UPSLOPE FLOW...WE WOULD EXPECT MVFR AND PERHAPS IFR TO MOST LIKELY DEVELOP ALONG AND WEST OF HIGHWAY 61 WEDNESDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CDC SHORT TERM...TAYLOR LONG TERM...CDC AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
637 PM CDT TUE AUG 6 2013 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE THROUGH TONIGHT SPARKING TSTMS...SOME SEVERE. A SUBTROPICAL DISTURBANCE...CURRENTLY ACROSS AZ...UT AND WRN COLO WILL LIFT THROUGH THE SRN PTN OF FCST AREA WEDNESDAY AND THURSDAY PRODUCING RAIN...MAINLY SOUTH OF THE INTERSTATE 80. THE UPPER LEVEL LOW ACROSS HUDSON BAY WILL MIGRATE INTO THE CANADIAN MARITIMES THIS WEEKEND. IN DOING SO...A LOBE OF UPPER LEVEL ENERGY COULD PRODUCE THUNDERSTORMS ACROSS NRN NEB SATURDAY NIGHT AND SUNDAY. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 335 PM CDT TUE AUG 6 2013 TONIGHT AND WEDNESDAY...CONDITIONS FAIRLY UNSTABLE ACROSS SOUTHWEST INTO CENTRAL NEBRASKA...AND SCATTERED THUNDERSTORMS ARE STILL POSSIBLE. A COLD FRONT IS CURRENTLY MOVING SOUTH INTO NORTHERN NEBRASKA...WITH AN OLD OUTFLOW BOUNDARY NEARLY STATIONARY ACROSS SOUTHWEST NEBRASKA. THESE FEATURES COULD SERVE AS A FOCUS FOR THUNDERSTORM INITIATION YET THIS AFTERNOON. OTHER STORMS DEVELOPING ACROSS EASTERN WYOMING ARE EXPECTED TO MOVE EAST AND SOUTHEAST AND MAY MOVE INTO SOUTHWEST NEBRASKA LATER THIS EVENING. COVERAGE OF ANY STORM ACTIVITY IS EXPECTED TO REMAIN WIDELY SCATTERED AS OVERALL FORCING IS FAIRLY WEAK...AND NO REAL DEFINED UPPER LEVEL DISTURBANCE IS PRESENT. WILL KEEP POPS AT 30 PERCENT OR LESS TONIGHT DUE TO THESE FACTORS. A SUB TROPICAL DISTURBANCE WILL APPROACH THE AREA FROM THE SOUTHWEST CONUS WEDNESDAY...BUT CURRENT INDICATIONS ARE THAT THE MORE SIGNIFICANT RAIN FROM THIS SYSTEM WILL REMAIN TO OUR SOUTH AND WEST DURING THE DAY WEDNESDAY. COOLER CONDITIONS ARE EXPECTED FOR WEDNESDAY IN THE WAKE OF THE COLD FRONT AND WITH THE INCREASED CLOUD COVER FROM THE SUB TROPICAL DISTURBANCE. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 335 PM CDT TUE AUG 6 2013 WEDNESDAY NIGHT THROUGH FRIDAY... ALL EYES ARE ON THE SUBTROPICAL DISTURBANCE CURRENTLY ACROSS AZ/SRN UT/SWRN COLO. THE MODEL CONSENSUS TAKES THIS DISTURBANCE THROUGH NERN COLO/SWRN NEB/NWRN KS WEDNESDAY NIGHT AND THURSDAY. A CLOSED 700MB LOW FORMS BRIEFLY WEDNESDAY NIGHT AND THEN OPENS UP IN A POSITIVE FASHION THURSDAY. THUS IT WOULD APPEAR MOST OF THE RAIN WILL FALL ON THE FORWARD SIDE OF THE DISTURBANCE WEDNESDAY NIGHT AND THURSDAY. THE HPC...GEM...GFS...NAM AND ECM FCSTS WERE BLENDED FOR THE QPF FORECAST WHICH PRODUCES 1/2 TO 1 INCH OF RAIN ALONG AND SOUTH OF INTERSTATE 80. POPS ARE STILL LIMITED TO 40 PERCENT GIVEN THE TIMING AND TRACK UNCERTAINTIES OF A SYSTEM ROTATING NORTH AND EAST AROUND A SUBTROPICAL HIGH. THE MODELS DO SHOW A COLD FRONT APPROACHING NCNTL NEB LATE THURSDAY AFTN WHICH COULD ADD FOCUS TO THE RAIN EVENT. K-INDICES ARE OPERATING IN THE 30-35C RANGE. THE MODELS SHOW SOME CLEARING THURSDAY AFTN WHICH WOULD ALLOW TEMPS TO RISE INTO THE 70S. FOR FRIDAY...THE NAM...ECM AND GEM SHOW SOME AFTN TSTM ACTIVITY DEVELOPING OFF THE LARAMIE RANGE WHICH COULD DRIFT INTO WRN NEB LATE IN THE AFTERNOON. TEMPERATURES SHOULD RISE INTO THE UPPER 70S TO LOWER 80S. OTHERWISE FRIDAYS FORECAST IS UNEVENTFUL. THE NAM SHOWED STORMS FIRING OFF THE THE BACK HILLS THURSDAY AS THE COLD MOVES THROUGH. THESE STORMS...IF THEY DEVELOP...WOULD MOVE SOUTHEAST INTO NCNTL NEB LATE IN THE AFTN. FRIDAY NIGHT THROUGH TUESDAY...RAIN CHANCES PERK UP SATURDAY NIGHT AND SUNDAY AS A REINFORCING COLD FRONT DROPS THROUGH THE NRN PLAINS AND INTO NCNTL NEB. THE GEM...GFS AND ECM ARE IN GOOD AGREEMENT TAKING A LOBE OF ENERGY THRU THE NRN PLAINS AS THE HUDSON BAY LOW KICKS OUT INTO THE CANADIAN MARITIMES. MOST OF THIS ENERGY AND RAINFALL TRACK THROUGH SD SO JUST NRN NEB PICKS UP A 1/4 INCH OR SO RAINFALL. THE REST OF THE FCST IS JUST ISOLATED POPS. THE 300MB JET MAX SWINGS EAST FOCUSING THE BEST SUPPORT FOR RAINFALL INTO THE OHIO VALLEY. FARTHER WEST...A BELT OF STRONG WINDS ALOFT WILL CONTINUE ACROSS KS AND COLO. THIS COULD SUPPORT ISOLATED DIURNALLY DRIVEN TSTMS ACROSS WRN/NCNTL NEB. IT LOOKS LIKE THE SUBTROPICAL HIGH SHIFTS EAST INTO TEXAS A BIT AND TAKES THE BEST MOISTURE THRU THE MID SOUTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 637 PM CDT TUE AUG 6 2013 THE HRRR IS SENDING A SQUALL LINE THROUGH SWRN NEB THIS EVENING. THE MODEL SHOWS IT COULD AFFECT KLBF BUT THE MODEL TENDS TO OVERDO COVERAGE. THUS THE BEST FORECAST WOULD BE FOR VCTS AT KLBF THIS EVENING UNTIL WE ACERTAIN THE TRACK OF THIS SQUALL LINE. OTHERWISE VFR IS EXPECTED THIS EVENING. RAIN AND PERHAPS THUNDER IS EXPECTED WEDNESDAY ACROSS SWRN AND SCNTL NEB...MAINLY ALONG AND SOUTH OF I-80. SOME OF THE MODELS ARE FAST. SO WE ARE PLANNING ON VFR AT KLBF AND KVTN UNTIL WE ASCERTAIN THE TIMING AND EXPECTED FLIGHT CATEGORIES. GIVEN THE UPSLOPE FLOW...WE WOULD EXPECT MVFR AND PERHAPS IFR TO MOST LIKELY DEVELOP ALONG AND WEST OF HIGHWAY 61 WEDNESDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CDC SHORT TERM...TAYLOR LONG TERM...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1131 AM CDT MON AUG 5 2013 .AVIATION... 18Z TAFS FOR KOFK...KOMA AND KLNK. ALTHOUGH MORNING CONVECTION WAS SHOWING APPARENT SIGNS OF WEAKENING IT COULD STILL IMPACT TAF SITES. WITH 18Z FORECAST IT APPEARED KOMA WAS AIRPORT POTENTIALLY IMPACTED AND A BRIEF TSTM TEMPO GROUP WAS FORECAST. HOWEVER...TRENDS WILL NEED MONITORING AS WEAK BOUNDARY IN REGION AND AFTERNOON HEATING COULD INCREASE COVERAGE AGAIN. OTHERWISE...A GENERAL DECREASE IN MVFR CIGS EXPECTED THROUGH AFTERNOON...WITH VFR CIGS OR NO CIGS BY LATE AFTERNOON. LATER TONIGHT IFR CIGS COULD AGAIN DEVELOP AHEAD OF ANOTHER TSTM COMPLEX PROBABLY MOVING TOWARD ERN NEBR BY TUESDAY MORNING. THIS IFR CIG MENTION WAS MAINTAINED AT KOFK/KLNK WITH TEMPO LOW MVFR CIG FORECAST AT KOMA AT THIS TIME. A PROB30 GROUP WAS CARRIED AT KOFK WHERE TSTM ACTIVITY APPEARED MOST POSSIBLE TUESDAY MORNING. CHERMOK && .PREV DISCUSSION... /ISSUED 352 AM CDT MON AUG 5 2013/ DISCUSSION... SHORT TERM CONCERNS WILL BE LOW CLOUDS AND FOG THIS MORNING AND POTENTIAL FOR ISOLATED SHOWERS AND THUNDERSTORMS TODAY IN THE NORTH THEN ATTENTION TURNS TO TUESDAY CONVECTIVE POTENTIAL. WATER VAPOR SATELLITE IMAGERY AND LIGHTNING DATA SHOW MOISTURE STREAMING NORTHWARD ACROSS MEXICO INTO THE FOUR CORNERS REGION INTO THE PLAINS AND THEN SOUTHEAST TOWARD THE LOWER MISSISSIPPI VALLEY... ANTI-CYCLONICALLY AROUND THE LARGE AREA OF H5 HIGH PRESSURE CENTERED OVER NEW MEXICO AND WEST TEXAS. MEANWHILE...CONVECTION WAS ALSO MOVING INTO THE PACIFIC NORTHWEST AND ACROSS THE NORTHERN PLAINS...WHERE THE STRONGER H3 JET RESIDED. THERE WERE 10 TO 20 METER HEIGHT FALLS ASSOCIATED WITH SHORTWAVE TROFS OVER NORTH DAKOTA AND ALSO NEAR SPRINGFIELD MISSOURI. THERE WAS ABUNDANT MOISTURE OVER THE PLAINS WITH MOST LOCATION ON THE PWAT CHART BETWEEN 100-160% OF NORMAL. WIDESPREAD H85 DEWPOINTS OF +12 TO +16C...WITH A MAX OF +18C AT DDC. H7 DEWPOINTS WERE +9 DEG C AT DDC AND +6 AT TOP. H7 TEMPERATURES HAD WARMED INTO THE +10 TO +14 C RANGE FOR MUCH OF THE PLAINS...WITH THE COOLER TEMPS TOWARD ABR...TOP/SPRINGFIELD. THERE WERE TWO THERMAL RIDGES AT H85...ONE WAS NOSING INTO THE NEBRASKA PANHANDLE AND THE OTHER WAS NOSING INTO THE TEXAS PANHANDLE AND OKLAHOMA. THE LATEST WSR-88D RADAR MOSAIC SHOWED THREE CONVECTIVE COMPLEXES....ONE ACROSS MN/NRN IA...ONE OVER SOUTHEAST KANSAS AND ONE OVER WESTERN SOUTH DAKOTA. AFTER SOME MORNING CLOUDS AND FOG...A STRONG SHORTWAVE TROF OVER NORTH DAKOTA WILL CONTINUE TO PUSH SOUTHEAST TODAY AND WILL DRAG A FRONT INTO NORTHEAST NEBRASKA. THE BULK OF THE CONVECTIVE ACTIVITY SHOULD REMAIN TO OUR NORTH AND EAST...LIMITED BY THE WARM MID LEVEL TEMPERATURES LOCALLY...HOWEVER ISOLATED ELEVATED THUNDERSTORMS COULD MAKE IT INTO NORTHEAST NEBRASKA AND WEST CENTRAL IOWA. THERE IS STRONG DEEP LAYER SHEAR OF 50KTS...SO STORMS WILL NEED TO BE WATCHED NEAR THE SD/NEB BORDER. MOST OF THE SHORT RANGE MODELS LIMIT THE SOUTHWARD PROGRESS DURING THE DAY...HOWEVER THE LATEST RAP IS MORE AGGRESSIVE WITH PRECIPITATION MAKING IT FARTHER SOUTH...SO THIS WILL NEED TO BE WATCHED. WARMER H85 TEMPS ARE EXPECTED AND HAVE HIGHS IN THE 80S ALTHOUGH IF CLOUDS HANG ON...THIS COULD KEEP THE HIGHS A LITTLE LOWER. MONDAY NIGHT...AN MCS IS FORECAST TO DEVELOP OVER THE NORTHERN PLAINS AND SPREAD SOUTHEAST. THIS SYSTEM HAS DECENT INSTABILITY OF 3-4000J/KG AND DEEP LAYER SHEAR OF 45-53KTS THUS STORMS COULD BE SEVERE. THE MODELS HAVE A VARIETY OF SOLUTIONS ON THE PLACEMENT OF THE BEST PRECIP...HOWEVER WILL MAINTAIN HIGH POPS WITH THE FRONT TUESDAY INTO TUESDAY EVENING. POOLING OF MOISTURE ALONG THE FRONT COULD RESULT IN LOCALLY HEAVY RAINS. DRYING ENSUES WITH SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTH SHOULD SHUT DOWN THE PRECIPITATION TUESDAY NIGHT AND WEDNESDAY. HIGHS WEDNESDAY SHOULD BE COOLER...IN THE 70S TO LOWER 80S. RETURN FLOW SETS UP WEDNESDAY NIGHT AND COULD SEE SOME STORMS RETURN ESPECIALLY SOUTHWEST. THE EXTENDED THURSDAY THROUGH SUNDAY. H5 LOW PRESSURE OVER HUDSON BAY WILL SLOWLY MOVE EAST WITH BUILDING HEIGHTS OVER THE ROCKIES AND NORTHWEST FLOW ALOFT FOR THE FORECAST AREA. DEEP MOISTURE WILL REMAIN IN PLACE...ESPECIALLY FOR THE SOUTHERN PART OF THE FORECAST AREA AND THIS IS WHERE THERE WOULD BE A HIGHER RISK OF THUNDERSTORMS. SHORTWAVES IN THE NORTHWEST FLOW ALOFT AND STORMS THAT FORM IN THE WESTERN HIGH PLAINS COULD ROLL EAST FRIDAY NIGHT INTO SUNDAY NIGHT...ALTHOUGH THE EASTERLY LOW LEVEL FLOW OFF THE SURFACE HIGH COULD LIMIT COVERAGE. THERE ARE DECENT MODEL DIFFERENCES BY SUNDAY AS TO WHERE THE FRONTAL SYSTEMS WILL BE THUS HAVE LEFT IN THE CHC POPS. HIGHS WILL CONTINUE TO BE AT OR BELOW NORMAL. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
635 AM CDT MON AUG 5 2013 .AVIATION...12Z TAFS FOR KOFK...KLNK AND KOMA. LOW CLOUDS WILL LINGER ACROSS EASTERN NEBRASKA THROUGH MUCH OF THE MORNING BEFORE SCATTERING/LIFTING TO VFR. EXPECT IFR CIGS AND MVFR VSBYS AT ALL TAF SITES...BUT IFR VSBYS AT KOFK WILL BE POSSIBLE AT LEAST THROUGH 15Z. VFR CONDITIONS SHOULD PREVAIL BETWEEN 18Z AND 06Z BEFORE MORE LOW CLOUDS AND FOG REDEVELOP TOWARD THE END OF THE TAF PERIOD. THERE IS AN OUTSIDE CHANCE FOR THUNDERSTORMS BETWEEN 18Z AND 00Z...ESPECIALLY IN THE KOFK AREA. THEN MORE STORMS IN WESTERN AND CENTRAL NEBRASKA COULD WORK INTO KOFK/KLNK AREAS AFTER 06Z. BOTH POTENTIAL THUNDERSTORM CHANCES ARE NOT MENTIONED IN TAFS AT THIS TIME DUE TO LOW CONFIDENCE OF OCCURRENCE AND EXPECTED ISOLATED NATURE OF STORMS. DERGAN && .PREV DISCUSSION... /ISSUED 352 AM CDT MON AUG 5 2013/ DISCUSSION... SHORT TERM CONCERNS WILL BE LOW CLOUDS AND FOG THIS MORNING AND POTENTIAL FOR ISOLATED SHOWERS AND THUNDERSTORMS TODAY IN THE NORTH ..THEN ATTENTION TURNS TOTUESDAY CONVECTIVE POTENTIAL. WATER VAPOR SATELLITE IMAGERY AND LIGHTNING DATA SHOW MOISTURE STREAMING NORTHWARD ACROSS MEXICO INTO THE FOUR CORNERS REGION INTO THE PLAINS AND THEN SOUTHEAST TOWARD THE LOWER MISSISSIPPI VALLEY... ANTI-CYCLONICALLY AROUND THE LARGE AREA OF H5 HIGH PRESSURE CENTERED OVER NEW MEXICO AND WEST TEXAS. MEANWHILE...CONVECTION WAS ALSO MOVING INTO THE PACIFIC NORTHWEST AND ACROSS THE NORTHERN PLAINS...WHERE THE STRONGER H3 JET RESIDED. THERE WERE 10 TO 20 METER HEIGHT FALLS ASSOCIATED WITH SHORTWAVE TROFS OVER NORTH DAKOTA AND ALSO NEAR SPRINGFIELD MISSOURI. THERE WAS ABUNDANT MOISTURE OVER THE PLAINS WITH MOST LOCATION ON THE PWAT CHART BETWEEN 100-160% OF NORMAL. WIDESPREAD H85 DEWPOINTS OF +12 TO +16C...WITH A MAX OF +18C AT DDC. H7 DEWPOINTS WERE +9 DEG C AT DDC AND +6 AT TOP. H7 TEMPERATURES HAD WARMED INTO THE +10 TO +14 C RANGE FOR MUCH OF THE PLAINS...WITH THE COOLER TEMPS TOWARD ABR...TOP/SPRINGFIELD. THERE WERE TWO THERMAL RIDGES AT H85...ONE WAS NOSING INTO THE NEBRASKA PANHANDLE AND THE OTHER WAS NOSING INTO THE TEXAS PANHANDLE AND OKLAHOMA. THE LATEST WSR-88D RADAR MOSAIC SHOWED THREE CONVECTIVE COMPLEXES....ONE ACROSS MN/NRN IA...ONE OVER SOUTHEAST KANSAS AND ONE OVER WESTERN SOUTH DAKOTA. AFTER SOME MORNING CLOUDS AND FOG...A STRONG SHORTWAVE TROF OVER NORTH DAKOTA WILL CONTINUE TO PUSH SOUTHEAST TODAY AND WILL DRAG A FRONT INTO NORTHEAST NEBRASKA. THE BULK OF THE CONVECTIVE ACTIVITY SHOULD REMAIN TO OUR NORTH AND EAST...LIMITED BY THE WARM MID LEVEL TEMPERATURES LOCALLY...HOWEVER ISOLATED ELEVATED THUNDERSTORMS COULD MAKE IT INTO NORTHEAST NEBRASKA AND WEST CENTRAL IOWA. THERE IS STRONG DEEP LAYER SHEAR OF 50KTS...SO STORMS WILL NEED TO BE WATCHED NEAR THE SD/NEB BORDER. MOST OF THE SHORT RANGE MODELS LIMIT THE SOUTHWARD PROGRESS DURING THE DAY...HOWEVER THE LATEST RAP IS MORE AGGRESSIVE WITH PRECIPITATION MAKING IT FARTHER SOUTH...SO THIS WILL NEED TO BE WATCHED. WARMER H85 TEMPS ARE EXPECTED AND HAVE HIGHS IN THE 80S ALTHOUGH IF CLOUDS HANG ON...THIS COULD KEEP THE HIGHS A LITTLE LOWER. MONDAY NIGHT...AN MCS IS FORECAST TO DEVELOP OVER THE NORTHERN PLAINS AND SPREAD SOUTHEAST. THIS SYSTEM HAS DECENT INSTABILITY OF 3-4000J/KG AND DEEP LAYER SHEAR OF 45-53KTS THUS STORMS COULD BE SEVERE. THE MODELS HAVE A VARIETY OF SOLUTIONS ON THE PLACEMENT OF THE BEST PRECIP...HOWEVER WILL MAINTAIN HIGH POPS WITH THE FRONT TUESDAY INTO TUESDAY EVENING. POOLING OF MOISTURE ALONG THE FRONT COULD RESULT IN LOCALLY HEAVY RAINS. DRYING ENSUES WITH SURFACE HIGH PRESSURE BUILDING IN FROM THE NORTH SHOULD SHUT DOWN THE PRECIPITATION TUESDAY NIGHT AND WEDNESDAY. HIGHS WEDNESDAY SHOULD BE COOLER...IN THE 70S TO LOWER 80S. RETURN FLOW SETS UP WEDNESDAY NIGHT AND COULD SEE SOME STORMS RETURN ESPECIALLY SOUTHWEST. THE EXTENDED THURSDAY THROUGH SUNDAY. H5 LOW PRESSURE OVER HUDSON BAY WILL SLOWLY MOVE EAST WITH BUILDING HEIGHTS OVER THE ROCKIES AND NORTHWEST FLOW ALOFT FOR THE FORECAST AREA. DEEP MOISTURE WILL REMAIN IN PLACE...ESPECIALLY FOR THE SOUTHERN PART OF THE FORECAST AREA AND THIS IS WHERE THERE WOULD BE A HIGHER RISK OF THUNDERSTORMS. SHORTWAVES IN THE NORTHWEST FLOW ALOFT AND STORMS THAT FORM IN THE WESTERN HIGH PLAINS COULD ROLL EAST FRIDAY NIGHT INTO SUNDAY NIGHT...ALTHOUGH THE EASTERLY LOW LEVEL FLOW OFF THE SURFACE HIGH COULD LIMIT COVERAGE. THERE ARE DECENT MODEL DIFFERENCES BY SUNDAY AS TO WHERE THE FRONTAL SYSTEMS WILL BE THUS HAVE LEFT IN THE CHC POPS. HIGHS WILL CONTINUE TO BE AT OR BELOW NORMAL. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
312 AM EDT WED AUG 7 2013 .SYNOPSIS... A PATTERN MORE TYPICAL OF SUMMER...WARM TEMPERATURES AND AFTERNOON AND EVENING THUNDERSTORMS WILL DEVELOP OVER THE NEXT FEW DAYS ACROSS THE AREA. LATE IN THE PERIOD RAIN CHANCES MAY INCREASE AS A FRONT MOVES CLOSER TO THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...AFTER YESTERDAY`S FORECAST DEBACLE ALONG AND WEST OF THE INTERSTATE 95 CORRIDOR...I AM HOPING THIS IS A BETTER FORECAST FOR TODAY. SURFACE HIGH PRESSURE IS DEPARTING THE COASTAL MID-ATLANTIC REGION...BUT A RIDGE AXIS REMAINS ENTRENCHED ACROSS THE INTERIOR CAROLINAS. EASTERLY FLOW ACROSS THE ATLANTIC IS GRADUALLY WARMING AND MOISTENING AS THE SOURCE REGION FOR THE INCOMING STREAMLINES SHIFTS TO BERMUDA INSTEAD OF EASTERN CANADA. THE UPPER LEVEL PATTERN FEATURES A 500 MB RIDGE OVER EASTERN TEXAS WITH A WEAKENING LONGWAVE TROUGH OVER THE EASTERN U.S. 500 MB HEIGHTS SHOULD RISE BY ABOUT 20 METERS OVER THE CAROLINAS TODAY. ONE POTENTIAL PROBLEM DESPITE THE BUILDING RIDGE IS A WEAK SHORTWAVE TROUGH EMBEDDED IN THE WESTERLY UPPER LEVEL FLOW. THIS FEATURE IS COLOCATED WITH A CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA EARLY THIS MORNING...AND IS DEPICTED BETTER IN THE GFS THAN THE NAM. IT SHOULD TRANSIT THE EASTERN CAROLINAS DURING THE LATE AFTERNOON HOURS...WEAKENING ALONG THE COAST THIS EVENING AS A COL (WEAK WIND REGION) DEVELOPS IN BETWEEN THE TEXAS AND BERMUDA RIDGES. AT THE RISK OF MAKING THE SAME MISTAKE I DID YESTERDAY...I SEE A VERY LOW RISK FOR SHOWERS TODAY GIVEN INSUFFICIENT MOISTURE AND WEAK LAPSE RATES WITHIN THE LOWER TROPOSPHERE. FORECAST SOUNDINGS FROM THE GFS...ECMWF AND RUC SHOW A CAPPED CONVECTIVE ENVIRONMENT. ONLY THE NAM DEVELOPS ANY SUBSTANTIAL SURFACE-BASED OR ELEVATED INSTABILITY TODAY (DUE TO SURFACE DEWPOINTS THAT LOOK TOO HIGH) BUT THAT MODEL ALSO SHOWS INSUFFICIENT FORCING FOR SHOWERS. THE 200-300 MB JET STREAM IS NOW WELL NORTH AND EAST OF THE CAROLINAS...TAKING ANY POTENTIAL UPPER DIVERGENT REGIONS OUT OF THE PICTURE LOCALLY. SCATTERED MID-LEVEL CLOUDS COULD BECOME A LITTLE MORE SUBSTANTIAL AT TIMES INLAND TODAY...BUT SHOULD NOT DO TOO MUCH TO HOLD TEMPERATURES DOWN. HIGHS ARE EXPECTED TO REACH 87-88 INLAND WITH MID 80S NEAR THE COAST. FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH LOWS 69-74...WARMEST AT THE COAST. MODELS ARE HINTING AT THE SOUTHEAST FLOW ALONG THE COAST POTENTIALLY YIELDING SOME MARINE SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A TREND OF INCREASING POPS TOWARD SUNRISE THURSDAY AT THE BEACHES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE SEABREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS UNCHANGED FOR THE MOST PART. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...EXPECT VFR THROUGH THE PERIOD WITH THE EXCEPTION OF MVFR DUE TO FOG AT THE INLAND SITES LATE OVERNIGHT BEFORE DAYBREAK. LIGHT WINDS AND MAINLY MID AND HIGH CLOUDS WILL CONTINUE INTO THE OVERNIGHT HOURS. ANTICIPATE MVFR DUE TO FOG TO DEVELOP IN A FEW HOURS AT FLO AND LBT. MOISTURE POOLING AROUND 2000 FT AGL COULD ALSO DEVELOP SOME STRATUS AT THE INLAND AIRPORTS. AFTER DAYBREAK...VFR WILL PREVAIL WITH LIGHT SOUTH-SOUTHEAST WINDS BECOMING AOB 10 KTS ON WEDNESDAY...BECOMING LIGHT INTO THE EVENING HOURS. EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM WEDNESDAY...HIGH PRESSURE OFF THE MID-ATLANTIC COAST SHOULD MOVE FARTHER OUT TO SEA TODAY...BUT A SURFACE RIDGE AXIS WILL REMAIN PARKED ACROSS INTERIOR NORTH CAROLINA. UNTIL THIS RIDGE AXIS BREAKS DOWN DURING THE DAY THURSDAY OUR WIND DIRECTIONS WILL NOT VEER SIGNIFICANTLY FROM EAST-SOUTHEAST. MODELS ARE IN EXCELLENT AGREEMENT WITH WIND SPEEDS...EXPECTED TO AVERAGE 10 KNOTS BOTH TODAY AND TONIGHT. SEAS CURRENTLY AROUND 2 FT SHOULD CHANGE VERY LITTLE THROUGH TONIGHT WITH VIRTUALLY NO SWELL ENERGY VISIBLE ON SPECTRAL WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY. SHOWER CHANCES WILL REMAIN VERY LOW THROUGH THIS EVENING...BUT MAY INCREASE A LITTLE AFTER MIDNIGHT TONIGHT...ESPECIALLY OFFSHORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS. THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN KNOTS.WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT SEAS OF 2-3 FEET. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...TRA SHORT TERM...SHK LONG TERM...SHK AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT WED AUG 7 2013 .SYNOPSIS... A MOIST SOUTHERLY RETURN FLOW WILL PREVAIL ACROSS THE REGION THROUGH MID TO LATE WEEK...ON THE WESTERN PERIPHERY OF AN OFFSHORE RIDGE. A COLD FRONT WILL MOVE INTO THE REGION BY THIS WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 255 AM WEDNESDAY... PERSISTENCE WILL DOMINATE THE FORECAST TODAY AS SOUTHERLY LOW-LEVEL FLOW CONTINUES BENEATH WEST-NORTHWESTERLY FLOW ALOFT. WEAK WARM ADVECTION...MASS CONVERGENCE ALONG THE HIGHER TERRAIN... AND MOISTURE POOLING OVER WESTERN WILL PROMOTE SCATTERED SHOWERS BY THIS AFTERNOON. THE MOST RECENT HRRR RUN INDICATES SHOWERS NEAR THE TRIAD BY AROUND NOON. DESPITE DEWPOINTS IN THE MID AND UPPER 60S...WIDESPREAD CLOUD COVER...BOTH AT LOW-LEVELS AND ALOFT...ALONG WITH WEAK MID-LEVEL LAPSE RATES WILL KEEP MLCAPE AT 500 J/KG OR LESS EAST OF THE MOUNTAINS. A WEAK UPPER DISTURBANCE LEFT OVER FROM CONVECTION OVER MISSOURI IS CROSSING THE TN VALLEY THIS MORNING...BUT THE MODEL CONSENSUS IS FOR THE DISTURBANCE TO CONTINUE TO WEAKEN AS IT DROPS EAST-SOUTHEAST TOWARD GEORGIA AND SC. THUS..THE CHANCE OF STORMS IS RATHER LOW TODAY. FORECAST SOUNDINGS SUGGEST A FEW MORE BREAKS IN CLOUD COVER TODAY...BUT THE STRATUS OVER THE WESTERN PIEDMONT THIS MORNING AND HIGH CLOUDS DRIFTING OVERHEAD SHOULD HOLD TEMPS DOWN OVER THE WESTERN CWA...WITH 82-87 A GOOD COMPROMISE OF STATISTICAL GUIDANCE. TONIGHT IN THE ABSENCE OF ANY SIGNIFICANT FORCING ALOFT...SHOWERS SHOULD BE DIURNAL IN NATURE AND THE OVERNIGHT PERIOD DRY. STRATUS IS LIKELY AGAIN OVER THE WESTERN PIEDMONT...WITH LOWS IN THE UPPER 60S TO AROUND 70...WARMEST IN THE WEST. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM WEDNESDAY... THURSDAY AND THURSDAY NIGHT... HEIGHTS ALOFT ARE EXPECTED TO RISE SLIGHTLY ON THURSDAY AS THE UPPER RIDGE OVER THE SOUTHERN US BRIEFLY EXPANDS EASTWARD AND A SHORTWAVE BEGINS TO DIVE SOUTH OUT OF CENTRAL CANADA. PW VALUES WILL CONTINUE TO CREEP UP TO ABOVE 1.75`...BUT THE LACK OF FORCING AND AFOREMENTIONED RIDGING ALOFT SHOULD KEEP CONVECTION CONFINED TO THE SEABREEZE AND HIGHER TERRAIN. HIGHS IN THE MID TO UPPER 80S. LOWS THURSDAY NIGHT AROUND 70. -SMITH FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN MIDLEVEL VORTEX MOVES FROM CENTRAL ONTARIO OVER QUEBEC THROUGH FRI NIGHT WITH THE TRAILING BROAD TROUGH AXIS SHIFTING ACROSS THE GREAT LAKES INTO THE MIDATLANTIC AND NORTHEAST. THE ASSOCIATED SURFACE COLD FRONT BECOMES MORE EAST-WEST ORIENTED TO OUR NORTH WHILE HEIGHTS ALOFT RISE SLIGHTLY OVER NC. THE UPPER LEVEL ANTICYCLONE TO OUR SOUTH SHIFTS EASTWARD... AND THE STRENGTHENING WESTERLY FLOW AT JET LEVEL INDUCES INCREASING UPPER DIVERGENCE OVER VA INTO CENTRAL NC (ALTHOUGH MODELS DIFFER ON THE DETAILS)... AND THE STRENGTHENING AND VEERING LOW LEVEL FLOW (WITH THE 850 MB TROUGH PASSAGE) RESULTS IN STRENGTHENING MOISTURE TRANSPORT PARTICULARLY OVER NORTH CENTRAL AND NORTHEAST NC IN THE AFTERNOON THROUGH EVENING. MODERATE INSTABILITY (MLCAPE OF 1200-1800 J/KG) IS EXPECTED FRI AFTERNOON/EVENING BUT WITH POOR DEEP-LAYER SHEAR UNDER 20 KTS FOR MUCH OF THE DAY...ALTHOUGH THIS DOES IMPROVE SLIGHTLY OVERNIGHT AS MIDLEVEL WINDS STRENGTHEN NEAR THE NC/VA BORDER... WHILE SOME WEAK ELEVATED INSTABILITY LINGERS. GIVEN THIS COMBINATION OF INSTABILITY AND WEAK DYNAMIC FORCING FOR ASCENT WITH HIGH PW AT OR ABOVE 2.0 INCHES... AT LEAST A 50% COVERAGE OF SHOWERS/STORMS IS JUSTIFIED ACROSS THE WRN/NRN CWA WHERE MOISTURE TRANSPORT IS HIGHEST ALONG THE LEE SURFACE TROUGH... WITH A LITTLE LOWER CHANCE OVER THE SOUTHEAST CLOSER TO THE MIDLEVEL ANTICYCLONE CENTER. HIGHS 88-92. RAIN CHANCES SHOULD WIND DOWN BY LATE EVENING AS LOW LEVEL FLOW BECOMES MORE WESTERLY WITH DOWNSLOPE DRYING AND INCREASING STABILITY AFTER SUNSET... BUT THE ANOMALOUSLY HIGH MOISTURE CONTENT OF THE COLUMN SUPPORTS A CONTINUED THREAT OF ISOLATED SHOWERS OVERNIGHT. LOWS 70-74. FOR SATURDAY/SATURDAY NIGHT: THIS STILL LOOKS LIKE THE WETTEST DAY OF THIS FORECAST. HEIGHTS ALOFT BEGIN TO FALL OVER THE APPALACHIANS INTO CENTRAL NC AS ENERGY TRACKS INTO THE TROUGH BASE... FROM ONTARIO ACROSS THE OH VALLEY... WHILE DEEP MOISTURE PERSISTS OVER THE LINGERING LEE TROUGH OVER CENTRAL NC AHEAD OF THE APPROACHING LARGE SCALE FRONTAL ZONE TO OUR NORTH AND NORTHWEST. THE INCREASING DPVA... HIGH LOW-LEVEL THETA-E... HIGH PW... AND MODERATE INSTABILITY SUPPORTS A 50-60% CHANCE OF SHOWERS/STORMS... HIGHEST IN THE NW AND NORTHERN CWA WHERE UPPER DIVERGENCE WILL BE GREATEST IN THE RIGHT ENTRANCE REGION OF THE 80-100 KT JET CORE OVER/OFF NEW ENGLAND. HIGHS 88-93 AS THE ABOVE-NORMAL THICKNESSES ARE TEMPERED BY ABUNDANT CLOUDINESS AND THE EARLY ONSET OF CONVECTION. LOWS AGAIN 70-74 WITH PLENTY OF CLOUDS AND A FEW RESIDUAL SHOWERS OVERNIGHT. -GIH && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 250 AM WEDNESDAY... THE AMPLIFICATION OF THE EASTERN US TROUGH CONTINUES INTO EARLY NEXT WEEK AS A SECONDARY VORTEX DROPS DOWN THROUGH ERN ONTARIO/JAMES BAY. MODELS INDICATE THAT THE SURFACE FRONT WILL SINK SLOWLY SE INTO FAR NRN AND WRN NC SUNDAY/SUNDAY NIGHT. WITH INCREASING DYNAMIC FORCING... MODERATE AFTERNOON INSTABILITY (2000-2500 J/KG MAINLY ALONG/EAST OF HIGHWAY 1)... AND CONTINUED HIGH MOISTURE THROUGH THE COLUMN... HIGH PROBABILITIES OF SHOWERS/STORMS SHOULD EXTEND THROUGH SUNDAY. THE GFS/ECMWF SWING THE MIDLEVEL LOW OVER SE ONTARIO AND SRN QUEBEC/UPPER ST LAWRENCE... AMPLIFYING THE SOUTHERN PORTION OF THE MEAN TROUGH SUFFICIENTLY SO AS TO NUDGE THE FRONT TO ERN/SRN NC FOR MONDAY/TUESDAY. CONSIDERING THAT THE MODEL RUNS FROM A FEW DAYS AGO WERE PUSHING THIS FRONT TO OUR SOUTH AS EARLY AS SUNDAY AND HAVE NOW BACKED OFF ON THAT SCENARIO... AND CONSIDERING THAT TRUE COLD FRONT PASSAGE THROUGH NC WITHOUT A STRONG AMPLIFYING TROUGH IS A RARITY... I HAVE SOME RESERVATIONS ABOUT BRINGING IN A LOT OF STABLE OR MARKEDLY COOLER AIR INTO THE NRN/WRN CWA. WILL HOLD ONTO DAILY CHANCE POPS OVER THE ERN/SRN CWA... NEAR THE LIKELY POSITION OF THE FRONTAL ZONE... WITH SLIGHTLY LOWER POPS (BUT NOT ZERO) OVER THE NW BOTH MONDAY AND TUESDAY. THICKNESSES SHOULD DIP A BIT HEADING INTO EARLY NEXT WEEK... SO EXPECT HIGHS TO TREND FROM AROUND 90 SUNDAY INTO THE MID-UPPER 80S BY TUESDAY. LOWS IN THE UPPER 60S TO LOWER 70S... SLIPPING 2-3 DEGREES FROM SUNDAY TO TUESDAY. -GIH && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 140 AM WEDNESDAY... THE PATTERN OF A MOIST SOUTHERLY FLOW AND BETTER CHANCES OF SHOWERS OVER THE WESTERN PIEDMONT WILL CONTINUE THROUGH THE TAF PERIOD. MVFR CEILINGS HAVE ALREADY DEVELOPED AT KGSO AND KINT...AND MAY LOWER TO IFR BY 10Z BASED ON FORECAST SOUNDINGS AND NEARBY OBSERVATIONS. TO THE EAST...MUCH DRIER LOW LEVEL AIR AND PERIOD OF HIGH CLOUDS SHOULD MAINTAIN VFR CONDITIONS...WITH JUST A SMALL CHANCE OF MVFR VSBYS AT KRWI/KFAY PRIOR TO SUNRISE. TODAY...WHERE STRATUS DOES DEVELOP...A SLOW LIFTING AND SCATTERING OF CEILINGS IS EXPECTED...ALTHOUGH VFR CONDITIONS SHOULD PREVAIL EVEN IN THE TRIAD BY MIDDAY. A FEW SHOWERS WILL BE POSSIBLE AROUND KGSO AND KINT...MAINLY AFTER 18Z. OUTLOOK... MORNING STRATUS AND AFTERNOON SHOWERS/STORMS WILL BE POSSIBLE EACH DAY FOR THE REMAINDER OF THE WEEK...ALTHOUGH THE COVERAGE OF SHOWERS AND STORMS IS EXPECTED TO INCREASE FRIDAY AND SATURDAY AS A COLD FRONT MOVES INTO THE REGION FROM THE NORTHWEST. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...SMITH SHORT TERM..SMITH/HARTFIELD LONG TERM...HARTFIELD AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
343 AM EDT WED AUG 7 2013 .SYNOPSIS... MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION. COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... DIFFICULT NEAR TERM FORECAST ON THIS GRAVEYARD SHIFT...IN THESE WANING DOG DAYS OF SUMMER. THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT WITH A FEW SHOWERS DEVELOPING ON RADAR. THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY. SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO 50 PERCENT RANGE THERE TODAY. PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT TERM PERIOD. WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM TEMPERATURES BELOW GFS MOS GUIDANCE. A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40 PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY TIME. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH SLOWER FRONT. CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR. WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST. HOWEVER...HAVE MADE SOME CHANGES TO REFLECT DIFFERENCES IN LATEST MODEL GUIDANCE. WPC INDICATES A COLD FRONT SHOULD BE LOCATED JUST TO OUR NORTHWEST EARLY IN THE PERIOD...SLOWLY SINKING SOUTH. SEVERAL MID-LEVEL SHORTWAVES AND A WEAK AREA OF LOW PRESSURE WILL THEN PUSH EAST MONDAY INTO TUESDAY. LATEST GFS IS SLOWER WITH THE SOUTHEAST PROGRESS OF THE COLD FRONT. WITH THIS IN MIND...HAVE HELD ONTO LOW POPS A LITTLE LONGER FOR SATURDAY NIGHT INTO SUNDAY. LOWERED HPC TEMP NUMBERS A FEW DEGREES AS THEY APPEAR TOO WARM FOR THE EXPECTED CONDITIONS. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... STILL THINKING CLOUDS WILL INCREASE AT 2 TO 4 THSD FT...WITH CEILINGS BECOMING MORE COMMON BETWEEN 09Z AND 12Z THIS MORNING. 00Z NAM SHOWS NICE 925 MB MOISTURE CONVERGENCE. 06Z VAD WINDS SHOWING FASTER 925 MB FLOW AT ILN DOWN TO JKL COMPARED TO RLX...BACKING THAT FORECAST. AS A RESULT...WILL HOLD OFF FORMING THICKER FOG...BUT 3 TO 5 MILES IN LIGHT FOG LIKELY IN SPOTS 09Z TO 12Z. A FEW SPOTTY SHOWERS COULD EASILY WITH THIS LOW LEVEL FORCING 08Z TO 12Z. THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING THE CONVECTION. CURRENTLY HAVE COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASING IN THE SOUTH AND TRI STATE AROUND HTS BY 18Z THEN MOVING EAST 18Z WEDNESDAY TO 00Z THURSDAY. QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3 THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT. VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z THURSDAY. VSBY AOB 3 MILES IN CONVECTION. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: SOME THICKER FOG COULD BRIEFLY FORM IN SPOTS IN WEST VIRGINIA FOR PREDAWN AND DAWN IF CLOUDS ARE SLOWER IN BECOMING A CEILING. TIMING AND COVERAGE OF CONVECTION COULD VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE WED 08/07/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY H H H H H M M M M M M M HTS CONSISTENCY H H H H H H M H M M M M BKW CONSISTENCY M H H H M H H H H M M M EKN CONSISTENCY M H L L L H M H M M M M PKB CONSISTENCY H H H H M M M M M M M M CKB CONSISTENCY H H H M M M M M M M M M AFTER 06Z THURSDAY... IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY AT NIGHT AND INTO THE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ SHORT TERM...MZ LONG TERM...JSH AVIATION...KTB
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1234 AM CDT WED AUG 7 2013 .AVIATION 06Z... MAIN FRONTAL BOUNDARY IS STILL LOCATED OFF TO THE SOUTHWEST TONIGHT...WITH CONVECTION GOING STRONG ALONG IT WELL TO OUR WEST IN OK/KS. THIS CONVECTION SHOULD TRACK ESE ALONG THE BOUNDARY AS IT PUSHES NORTH. SKIES WILL BE SLOW TO CLEAR FOR CSV...BUT BNA AND ESPECIALLY CKV SHOULD GET OUT OF THE BKN-OVC SKIES AT SOME POINT. WITH THE AMPLE LOW-LEVEL MOISTURE IN PLACE...MAY LOWER THE VSBYS IN THE TAFS CURRENTLY FOR THESE TWO LOCATIONS. CSV WILL EXPERIENCE MORE OF A LOWERED STRATUS CLOUD DECK THAN THE BR/FG POSSIBLE AT BNA/CSV. MAY DROP CONDITIONS DOWN TO IFR AT TIMES BETWEEN 06-12Z EARLY WED MORN. MAY SEE A FEW RANDOM SHRA POP UP...ESPECIALLY AT CSV...BEFORE STRONGER CONVECTION OVER THE PLAINS REACHES MIDDLE TN...SHOULD IT HOLD TOGETHER. IF IT FALLS APART...REDEVELOPMENT WEDNESDAY AFTERNOON IS LIKELY AND WILL HAVE TO INSERT TEMPOS IN OR PREVAILING GROUPS IN THE MOMENT FOR WEDNESDAY AFTER 18Z. ANY SHRA/TSRA ON WED WILL BRING BRIEF IFR VSBYS/CIGS AS WELL AS THE POTENTIAL FOR BRIEF WIND GUSTS OVER 40 KTS. OTHERWISE PREVAILING WINDS THROUGHOUT THIS TAF PERIOD SHOULD MAINLY BE LIGHT AND SOUTHEASTERLY. && .PREV DISCUSSION... /ISSUED 1021 PM CDT TUE AUG 6 2013/ UPDATE...RADAR CURRENTLY SHOWING WIDELY SCATTERED LIGHT SHOWERS ACROSS MIDDLE TENNESSEE, WITH VERY HUMID AIR MASS IN PLACE. EVENING SOUNDING FROM OHX SHOWS PRECIPITABLE WATER OF 2.11 INCHES AND A K-INDEX OF 33. LIFTED INDEX REMAINS -5.6, WITH CONVECTIVE AVAILABLE POTENTIAL ENERGY OF 2,528 J/KG, SO THERE`S PLENTY OF INSTABILITY AROUND, TOO. LATEST HRRR SHOWS SCATTERED ACTIVITY CONTINUING THROUGH THE NIGHT ACROSS MIDDLE TENNESSEE, BUT NOTHING TOO HEAVY. EARLIER DROPPED EVENING POP`S FROM LIKELY TO SCATTERED, LEAVING OVERNIGHT POP`S ALONE. GOING TO GO AHEAD AND REDUCE OVERNIGHT POP`S TO SCATTERED, TOO, AS THERE`S NOTHING TO SUGGEST MUCH OF AN INCREASE IN ACTIVITY BETWEEN 06Z AND 12Z. PREV DISCUSSION... /ISSUED 701 PM CDT TUE AUG 6 2013/ UPDATE...CUTTING EVENING POP`S BACK TO SCATTERED GIVEN THE LACK OF COVERAGE NOW AND THE LACK OF CONVECTIVE DEVELOPMENT FORECAST BY THE HRRR THROUGH 06Z. LEAVING OVERNIGHT POP`S UNCHANGED. PREV DISCUSSION... /ISSUED 636 PM CDT TUE AUG 6 2013/ UPDATE...FOR 00Z TAFS. AVIATION... AN UPPER LEVEL DISTURBANCE OVER WESTERN KY IS TRACKING ESE ACROSS THE REGION. THIS WILL CONTINUE A CHANCE FOR OFF AND ON SHRA/TSRA MAINLY IN A PERFECT LINE WITH OUR TERMINALS...FROM CKV TO BNA TO CSV...OVER THE NEXT FEW HOURS. ONCE THE DISTURBANCE MOVES EAST...SKIES SHOULD GO FROM BKN-OVC TO MORE FEW-SCT. HOWEVER TOWARDS DAWN...A WARM FRONTAL BOUNDARY SOUTHWEST OF THE REGION WILL PUSH NNE. VSBYS AHEAD OF THIS FEATURE COULD DROP GIVEN THE AMOUNT OF LOW-LEVEL MOISTURE AND THUS WE CONTINUE THE MVFR VSBYS AROUND DAWN (IFR AT CSV WITH MVFR CIGS). CHANCES FOR SHRA/TSRA TOMORROW MORNING COULD BE ELEVATED IF A CONVECTIVE COMPLEX CAN GET GOING OUT OVER THE PLAINS AND TRACK SOUTHEAST ALONG THE WARM FRONT...WHICH SHOULD AFFECT OUR TAF SITES SHOULD IT HOLD TOGETHER. OTHERWISE...A SCATTERED SHRA/TSRA CHANCE WILL BE THE RULE FOR MUCH OF WEDNESDAY. CAN HANDLE BETTER TIMING WITH TEMPOS/PREVAILING GROUPS WITH LATER FORECASTS. PREV DISCUSSION... /ISSUED 324 PM CDT TUE AUG 6 2013/ DISCUSSION...UNSETTLED AND SOMEWHAT UNUSUAL AUGUST WX WILL CONTINUE INTO THIS FORECAST PERIOD WITH INTERMITTENT SHOWERS AND THUNDERSTORMS. OUR MAIN CONCERN THROUGH THE NEXT COUPLE OF DAYS IS LOCALLY HEAVY RAINFALL. SO FAR...OUR COVERAGE AREA HAS NOT RECEIVED CONCENTRATED HEAVY RAINFALL AMOUNTS...SO WE DO NOT NEED ANY FLASH FLOOD WATCHES AT THIS TIME. VERY MOIST AIR HAS BEEN MOVING INTO MID TN...AND DEEP MOISTURE WILL REMAIN IN PLACE THROUGH AT LEAST THE NEXT 48 HOURS. FORECAST SOUNDINGS SHOW PRECIPITABLE WATER VALUES CLIMBING WELL OVER 2 INCHES AT TIMES. LIFT ACROSS A WARM FRONTAL ZONE WILL PERSIST THROUGH TONIGHT INTO WEDNESDAY MORNING AS ANOTHER UPPER WAVE APPROACHES FROM THE WEST. ADDITIONAL IMPULSES AND RESIDUAL BOUNDARIES WILL BE THE MAIN FACTORS TOMORROW AFTERNOON THROUGH THURSDAY. ALL OF THIS MEANS A GOOD CHANCE FOR MORE RAIN AND THUNDERSTORMS. UNFORTUNATELY...THERE ARE MANY UNCERTAINTIES REGARDING THE EXACT TIMING AND EVOLUTION OF THE SHOWERS AND STORMS...SO ANYONE WITH OUTDOOR PLANS WILL NEED TO KEEP A CLOSE WATCH ON RADAR LOOPS AND SHORT RANGE FORECAST UPDATES. IN GENERAL...1 TO 2 INCHES OF RAIN CAN BE EXPECTED THROUGH THE NEXT COUPLE OF DAYS...BUT THE STRONGER STORMS WILL EASILY PRODUCE LOCALIZED HEAVIER AMOUNTS...WITH RAINFALL RATES WELL OVER AN INCH PER HOUR POSSIBLE. A FEW STRONG STORMS WITH GUSTY WINDS ARE POSSIBLE TONIGHT. TOMORROW AFTERNOON AND THURSDAY AFTERNOON LOOK LIKE THE MOST UNSTABLE TIMES...WHEN A FEW SEVERE STORMS COULD DEVELOP. THESE WOULD PRODUCE LOCALIZED STRONG WIND GUSTS...HEAVY DOWNPOURS AND FREQUENT LIGHTNING. WE DO NOT SEE ANY WIDESPREAD OR WELL ORGANIZED SEVERE WX THREAT AT THIS TIME. BY FRIDAY AND CONTINUING INTO SATURDAY...RISING HEIGHTS WILL DEVELOP WITH A BERMUDA RIDGE BRIDGING ACROSS TO A SOUTHERN PLAINS RIDGE. THIS PATTERN WILL BRING VERY WARM AND HUMID CONDITIONS WITH SCATTERED DIURNALLY DRIVEN THUNDERSTORMS. MODELS INDICATE A FRONT DROPPING TOWARD THE AREA SATURDAY NIGHT INTO SUNDAY. SOME SLIGHTLY DRIER AIR MAY SEEP IN FROM THE NORTH...BUT WITH THE FRONT STALLING OVER THE AREA...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE. LOOKING AHEAD INTO NEXT WEEK...MORE OF THE SAME UNSETTLED SUMMER PATTERN OF 2013...AS NORTHWEST FLOW ALOFT BRINGS PERIODIC DISTURBANCES ACROSS THE REGION. 13 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ AL
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
448 AM CDT WED AUG 7 2013 .SHORT TERM... The main concern today will be convective chances late this afternoon and evening and heat advisory conditions across the Big Country. The upper level high will be positioned over eastern Texas today with a surface trough situated over our western counties by late afternoon. A cold front currently over southern Kansas is expected to drop south into northwest Texas by afternoon and become stationary through the evening hours. Compressional warming ahead of the front along with 850 millibar temperatures between 28 and 30 degrees Celsius will result in very hot temperatures again today. The hottest temperatures will occur across the northeastern half of the Big Country where compressional warming effects will be greatest. Afternoon highs across this area will top out between 103 and 106 degrees with corresponding heat indices between 104 and 107 degrees. Elsewhere, expected highs between 100 and 104 degrees with slightly lower heat indices. Included Jones County to the latest heat advisory which also covers Haskell, Throckmorton and Shackelford counties until 8 pm this evening. The aforementioned surface trough will be a focus for convective development by late afternoon across western counties as the cap weakens with intense heating. The NAM seems to have a better handle on this scenario as does the HRRR with both showing development along the trough axis by late afternoon. Went ahead and added slight pops generally west of a Throckmorton, Eden to Sonora line through early evening. While widespread severe weather is not expected, inverted V profiles with large dewpoint depressions will be favorable for a few microbursts with the stronger cells. Storms will be diurnally driven and should dissipate by mid to late evening with loss of heating. Low temperatures tonight will generally be in the mid and upper 70s. 24 .LONG TERM... Above normal temperatures will continue for all of West Central Texas through much of the extended forecast, although showers and thunderstorms may provide brief relief from the heat. Another hot day is forecast, although 850mb temperatures are slightly cooler than what we are expecting this afternoon. Highs should range from 99 to 102 over the southern counties to 101 to 104 across much of the Big Country. Isolated to scattered showers and thunderstorms are expected to develop along a surface trough across our western counties by late afternoon. I included a slight chance of showers and thunderstorms across mainly the western half of the area...with a chance across the extreme western Concho Valley and Big Country. In the meantime...a weak cold front will approach the northern Big Country during the late evening or early morning hours. Scattered showers and thunderstorms will be possible with the boundary...and I have kept a slight chance POPs going through the overnight hours for much of the Big Country. I trended my dewpoint temperatures closer to the more moist NAM through Friday. Model differences arise in the placement of a cold front across the region on Friday and Saturday. The NAM is the fastest with the boundary, stalling it across the Concho Valley during the early morning hours Friday, while the GFS and ECMWF are about 6 to 10 hours slower. Given the expected boundary across area and decent moisture to work with...I believe showers and thunderstorms will develop across parts of the Big Country, Heartland, and Concho Valley during the late afternoon/evening hours. Timing of the front will make a difference on both high temperatures and placement of best POPS, and for now I have kept a slight chance across generally the northern half of the region, and I tweaked highs down slightly. Although I cannot rule out an isolated shower or thunderstorms Saturday as the diffuse boundary remains in the area, confidence is not high enough to include in the forecast at this time. An inverted trough/low will move across South Texas Sunday into Monday, then into northern Mexico. Although the best dynamics associated with this feature will remain south of area area, it should pull in better gulf moisture Sunday and Monday. I cannot rule out diurnally driven isolated showers and thunderstorms during the afternoon hours, across mainly the southeast counties, but for now I have kept the forecast dry. High temperatures should be slightly above seasonal normals, generally in the mid and upper 90s, with lows in the 70s. Daniels && .PRELIMINARY POINT TEMPS/POPS... ABILENE 103 78 100 77 97 / 20 20 20 20 20 SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20 JUNCTION 103 76 101 73 100 / 10 10 5 5 10 && .SJT WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON. && $$ 24/Daniels
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1021 AM CDT WED AUG 7 2013 .UPDATE... ISSUED AT 1020 AM CDT WED AUG 7 2013 A FEW THUNDERSTORMS HAVE DEVELOPED ALONG THE COLD FRONT FROM JUST NORTHWEST OF MACOMB TO NEAR KEWANEE AND WERE MOVING EAST/NORTHEAST. SOME OF THE STORMS WILL PRODUCE BRIEF HEAVY RAINFALL. THE FRONT WILL CONTINUE TO SAG TO THE SOUTHEAST OF THE CWA BY NOON OR 1 PM. THE HRRR MESO MODEL INDICATES THE FRONT BECOMING MORE ACTIVE BY EARLY THIS AFTERNOON BUT BY THEN THE FRONT SHOULD BE SOUTHEAST OF THE DVN CWA. OTHERWISE...BEHIND THE FRONT WINDS WILL TURN NORTHWEST TO NORTH WITH GRADUALLY LOWERING DEW POINTS. CANADIAN HIGH WILL BUILD INTO THE REGION TONIGHT AND THURSDAY WITH MUCH MORE COMFORTABLE TEMPERATURES AND HUMIDITY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 322 AM CDT WED AUG 7 2013 WESTERN GRT LKS FRONTAL SYSTEM TO CONTINUE TO SWEEP THROUGH THE AREA THIS MORNING AND WILL WALK OUT ANY LINGERING CONVECTION/STORM CLUSTERS THROUGH 14Z TO 16Z...MAY DECAY BEFORE THEN LIKE LATEST HIRES MODEL RUNS SUGGEST. DESPITE FROPA...SOME LAG IN LLVL COOLER AIR ADVECTION AND EXPECT TEMPS TO WARM INTO THE LOW TO MID 80S IN THE SOUTHEASTERN HALF OF THE DVN CWA...UPPER 70S IN THE NORTHWESTERN FCST AREA. THESE TEMPS BANKING ON CONVECTIVE DEBRIS ERODING DIURNALLY. A BOUT OF PASSING SFC RIDGING WILL MAKE FOR A MAINLY CLEAR SKY AND COOLER TEMPS TONIGHT WITH SOME 50S OCCURRING NORTH OF I80. VALLEY FOG POSSIBLE. .LONG TERM...(THURSDAY THROUGH NEXT TUESDAY) ISSUED AT 322 AM CDT WED AUG 7 2013 GENERALLY BELOW NORMAL TEMP REGIME CONTINUES. MAIN STORY AT THE END OF THE WEEK WILL BE ACTIVE GRT BSN AND SOUTHERN STREAM FLOWS LOADED WITH MONSOONAL MOISTURE AND IF SOME OF IT CAN MAKE IT THIS FAR NORTH. LATEST MODEL TRENDS CONTINUE TO SHOW SOME PHASING POTENTIAL WITH NORTHERN PLAINS/UPPER MIDWEST TROFFINESS WHICH WOULD INDUCE SOME LLVL CYCLOGENESIS ACRS THE SOUTHERN PLAINS OVER TO THE MID MS RVR VALLEY. TIMING OF THIS PROCESS AND HOW FAR NORTH IT CAN MAKE IT STILL UNCERTAIN WITH MODEL VARIABILITY...BUT SIGNALS ARE THERE THAT AT LEAST THE SOUTHERN THIRD TO HALF OF THE CWA MAY GET IN ON SOME OVERRUNNING PRECIP/SOME POTENTIALLY DECENT SOAKING RAINS/ AT WEEKS END. THE 00Z GFS AND UKMET TARGET LATE THU NIGHT INTO FRIDAY...WHILE THE 00Z ECMWF IS POINTING AT FRI NIGHT AND NOT AS FAR NORTH AS THE PREVIOUS MENTIONED MODELS WITH IT/S PRECIP SWATH. MAY TREND TOWARD THE UKMET AND GFS WITH POPS INCREASING IN THE SOUTH THU NIGHT INTO FRI FOR NOW. BUST POTENTIAL FOR ADVERTISED TEMPS TO BE TOO WARM IN THE SOUTH HALF IF THIS MATERIALIZES BECAUSE OF PRECIP AND CLOUD COVER ESPECIALLY ON FRI. TELECONNECTION PERSISTENCE...THE GENERAL PATTERN OF NORTHWEST FLOW ALOFT WITH RE-ENFORCING DUMPS OF CANADIAN HIGHS DOWN THE UPPER MIDWEST AND WESTERN GRT LKS OVER THE WEEKEND AND INTO MID NEXT WEEK. SOME CHANCE OF A NORTHWEST FLOW PRECIS EVENT IN ONE OF THESE TRANSITIONS...WITH ONE WINDOW OF OPPORTUNITY LOOKING LIKE SUNDAY NIGHT INTO MONDAY. && .AVIATION...(FOR THE 12Z TADS THROUGH 12Z THURSDAY MORNING) ISSUED AT 637 AM CDT WED AUG 7 2013 A COLD FRONT WILL MOVE THROUGH THE AREA BY EARLY THIS AFTERNOON. GROUND FOG AND PATCHY STRATUS WITH BASES BELOW 1FT OCCURRING IN THE WARM MOIST AIR AHEAD OF THE FRONT SHOULD LIFT OR DISSIPATE WITH HEATING EARLY THIS MORNING. THE PREFRONTAL AIRMASS SHOULD DESTABILIZE ENOUGH BY LATE MORNING TO ALLOW A FEW THUNDERSTORMS TO DEVELOP ALONG THE FRONT. THESE STORMS COULD IMPACT KBRL LATE THIS MORNING OR EARLY THIS AFTERNOON. THERE SHOULD BE ENOUGH RESIDUAL MOISTURE BEHIND THE FRONT FOR SOME SCATTERED CU DEVELOPMENT THIS AFTERNOON. FORECAST MODELS WERE SUGGESTING THE POTENTIAL FOR SOME STRATUS MOVING OFF LAKE MICHIGAN LATE TONIGHT AND REACHING THE MISSISSIPPI RIVER BY THURSDAY MORNING. IF THIS OCCURS THEN KMLI AND KDBQ COULD SEE SOME LOW CIGS BY 12Z THURSDAY. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...HAASE SHORT TERM...12 LONG TERM...12 AVIATION...DLF
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
739 AM CDT Wed Aug 7 2013 ...UPDATED FOR AVIATION... .SYNOPSIS... ISSUED AT 1229 AM CDT WED AUG 7 2013 At 00z Wednesday a +100kt 250mb jet extended from South Dakota into the western great lakes. The right entrance region was located near central Nebraska/northern Kansas. At the 500mb level an upper level trough was located over eastern Montana and an upper level ridge axis was located across the pacific northwest. Further south over the southern plains an upper high was located near the gulf coast of Texas and an upper level low/trough moved northward out of Mexico into eastern Arizona. Convection that developed across southwest Kansas near the Colorado border around 00z Wednesday was currently moving east/southeast across south central Kansas at 05z. These storms appeared to located where the better 850mb moisture, frontogenesis, and warm air advection were occurring earlier this evening. Further north another area of convection had developed during the evening hours from northeast Colorado into western Nebraska. This a located near a surface trough of low pressure and where better moist upslope flow was present along with better mid level lapse rates. RAP also hinted at a subtle upper level wave was located in this area at 00z. && .SHORT TERM...(Today and tonight) ISSUED AT 251 AM CDT WED AUG 7 2013 The NAM, RAP, GFS were all in decent agreement this morning with moving an upper level trough across northern Kansas early this morning. Based on the 06z location of this upper wave it appears that an area of convection had developed ahead of this system based on the composite radar loop. Given this and the timing of the upper level trough will raise precipitation chances in the north to at least high chance for early this morning. Further south the chances for convection early will be less but still given weak lift forecast across southwest Kansas will keep some small pops going early today. Convection should briefly taper off as the upper level trough passes east of the area, however by the early afternoon the chances for convection will begin to improve, especially across far western and southwest Kansas where moist upslope flow is expected and better afternoon instability and 0-6km shear is forecast to be located. Convection will then increase in areal coverage as it spreads east across the remainder of western Kansas late today and overnight as the Arizona upper low/trough moves east across New Mexico. Heavy rainfall will still be an issue later today and overnight given the precipitable water content on the Dodge City soundings at 1.42 inches at 00z Wednesday. Also strong damaging winds and large hail will be possible from some these storms late today and early tonight. The flood watch currently in the effect still looks on track given several opportunities of heavy precipitation later today through Thursday. .LONG TERM...(Thursday through Tuesday) ISSUED AT 315 AM CDT WED AUG 7 2013 A cool and wet period is forecast for the area with much above average forecaster certainty for significant measurable rainfall through Thursday. The synoptic set up includes an already very moist atmosphere across the central high plains, characterized by dew points in the 60s and 70s. Additionally, and upper high center over the Southern Plains and Gulf region helping transport additional pacific moisture poleward. The kinematic fields will include the slow development of a Central Rockies through which will place Western Kansas under a favorable positive vorticity and warm advection region for maximum lift potential Thursday. Additionally, a surface/850 mb frontal zone will air in low level frontogenesis adding to the QG component. These elements have given enough confidence to raise precipitation chances into the categorical range during the day 2 period. The slow nature of this existing wave will create a fluid forecast situation . The jet streak will still leave a broad right rear quadrant entrance region into Friday, and thunderstorm cannot be ruled out through this period as well, although the trend would be downward. During this period it is likely that a widespread one to two inches of rain will fall over the entire southwest and central Kansas region. Areas of higher rainfall perhaps in excess of 5 inches are possible based on model run totals, but with relatively low forecaster confidence with respect to coverage. From Friday and onward increased ridging along the High Plains region will create a warming trend with opportunities for severe weather producing MCS events into early next week. && .AVIATION...(For the 12Z TAFS through 12Z Thursday morning) ISSUED AT 729 AM CDT WED AUG 7 2013 Overcast stratus will remain in the vfr category across the area with scattered lower stratus in some areas. Thunderstorms now exiting the region have promoted gusty nortwest winds around 20 knots thios morning. Deep moist convection will redevelop by afternoon and become more numerous in the evening. && .PRELIMINARY POINT TEMPS/POPS... DDC 82 66 72 65 / 40 90 80 60 GCK 80 65 71 65 / 40 90 80 60 EHA 83 65 73 62 / 70 70 80 50 LBL 83 67 75 64 / 40 80 80 50 HYS 79 65 76 65 / 50 90 80 70 P28 85 69 78 66 / 30 70 80 50 && .DDC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066- 079-081. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...RUSSELL AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
539 AM MDT WED AUG 7 2013 .UPDATE... ISSUED AT 745 PM MDT TUE AUG 6 2013 UPDATED TO REMOVE THE CONVECTIVE WATCH AND ACCOUNT FOR DECREASING THUNDERSTORM COVERAGE ACROSS THE SOUTH AND ADDITIONAL THUNDERSTORMS MOVING ACROSS NORTHEAST COLORADO INTO FAR SOUTHWEST NEBRASKA AND FAR NORTHWEST KANSAS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 222 PM MDT TUE AUG 6 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS FEATURE. THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT. WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 308 AM MDT WED AUG 7 2013 DIFFERENCES EXIST IN THE TIMING AND CHARACTER OF SHORTWAVE THAT MOVES ACROSS THE AREA EARLY IN THE EXTENDED PERIOD. AT THE START OF THE EXTENDED...RELATIVELY COOL/DRY NORTHEASTERLY POST FRONTAL SURFACE FLOW WILL BE IN PLACE ACROSS THE AREA EARLY SATURDAY. THIS WILL TRANSITION INTO SOUTHEASTERLY SURFACE FLOW LATER IN THE DAY ON SATURDAY. ADEQUATE MOISTURE AND LOW LEVEL CONVERGENCE MAY RESULT IN SHOWERS AND THUNDERSTORMS DEVELOPING SATURDAY AFTERNOON...ESPECIALLY ACROSS THE WESTERN PORTION OF THE AREA. ADDITIONALLY...CONVECTION THAT DEVELOPS FROM ELEVATED HEATING IN THE COLORADO MAY MOVE EASTWARD REACHING WESTERN PORTIONS OF THE AREA DURING THE EVENING. THE PATTERN CHANGES LITTLE THROUGH THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK. WESTERLIES ALOFT WILL CONTINUE WITH EMBEDDED MINOR DIFFICULT TO TIME SHORTWAVE TROUGHS NECESSITATING SLIGHT TO LOW CHANCE POPS EACH DAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 538 AM MDT WED AUG 7 2013 VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS. PRECIPITATION COULD BECOME RELATIVELY WIDESPREAD TODAY BUT THERE ARE SOME TIMING UNCERTAINTIES ON WHEN SHRA OR TSRA MIGHT IMPACT EITHER SITE. PRECIPITATION COULD CONTINUE OVERNIGHT TOO...BUT THE CURRENT TAF DOES NOT REFLECT THIS SINCE UNCERTAINTY EXISTS IN TIMING AND PLACEMENT. THE MOST LIKELY SITE TO BE IMPACTED BY SHOWERS OR THUNDERSTORMS TODAY THROUGH THE EVENING WILL BE GLD. SOME STRATUS MAY OCCUR IN THE MVFR CATEGORY OVERNIGHT AS WELL. SIGNIFICANT VISIBILITY RESTRICTIONS ARE UNLIKELY THROUGH THE NEXT 24 HOURS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KSZ027>029-041-042. CO...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR COZ092. NE...NONE. && $$ UPDATE...LOCKHART SHORT TERM...DR LONG TERM...BRB AVIATION...BRB
AREA FORECAST DISCUSSION
NWS JACKSON KY
1147 AM EDT WED AUG 7 2013 .UPDATE... ISSUED AT 1147 AM EDT WED AUG 7 2013 NDFD AND ZFP HAVE BEEN UPDATED. WHILE THE EARLY MORNING RUNS OF THE HRRR DID NOT DO A VERY GOOD JOB HANDLING THE CONVECTION THIS MORNING...THE 12 NAM SEEMS TO HAVE A BETTER HANDLE ON THINGS. BASED ON CURRENT TRENDS THE NUMEROUS SHOWERS IN THE SOUTHEAST WILL CONTINUE FOR THE NEXT FEW HOURS...WITH SCATTERED THUNDERSTORMS POSSIBLE ANYWHERE IN THE FORECAST AREA AS WE MOVE INTO THE AFTERNOON. HAVE ADJUSTED AFTERNOON CONVECTIVE COVERAGE TO NUMEROUS IN THE SOUTHEAST AND SCATTERED ELSEWHERE. AFTERNOON TEMPERATURES AND EXTENT OF CONVECTIVE DEVELOPMENT WILL BE ALMOST ENTIRELY DEPENDENT ON SKY COVER. STILL EXPECT ENOUGH BREAKS TO ALLOW TEMPERATURES TO RISE INTO THE LOWER 80S IN MOST AREAS. UPDATE ISSUED AT 956 AM EDT WED AUG 7 2013 NDFD AND ASSOCIATED PRODUCTS...INCLUDING ZFP HAVE BEEN UPDATED. THE NEAR TERM MODELS ARE NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...AND AS SUCH THIS THROWS DOUBT INTO THE NEAR TERM GUIDANCE FOR THE REST OF THE DAY INTO TONIGHT. THE 11Z HRRR SHOWED THE DEVELOPMENT OF THE CONVECTION EARLY THIS MORNING BUT QUICKLY HAD IT DIE AWAY BEFORE BRINGING AN ORGANIZED BAND OF CONVECTION ACROSS THE AREA FROM LATE MORNING INTO EARLY AFTERNOON WITH ANOTHER ROUND OF ORGANIZED CONVECTION FROM LATE AFTERNOON INTO THE EVENING. THE 12Z HRRR IS JUST COMING IN...AND STILL NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...BUT IS LEANING TOWARDS MORE DISORGANIZATION IN THE CONVECTION FOR THIS AFTERNOON. THERE WILL BE CONSIDERABLE DEBRIS CLOUDINESS ACROSS THE AREA TODAY...BUT EXPECT SOME BREAKS IN THE CLOUDS IN THE WAKE OF THE SHOWERS AND THUNDERSTORMS THAT OCCUR THIS MORNING. THIS WOULD ALLOW ADDITIONAL DESTABILIZATION WITH MORE AFTERNOON HEATING. WHERE BREAKS HAVE OCCURRED IN CENTRAL KY TEMPERATURES HAVE JUMPED INTO THE UPPER 70S AND AS SUCH WILL INCREASE AFTERNOON MAXIMUM TEMPERATURES SEVERAL DEGREES. WITH NUMEROUS SHOWERS ALREADY OCCURRING ACROSS THE AREA HAVE INCREASED RAIN CHANCES FOR THIS MORNING IN ALL BUT THE FAR NORTH...YIELDING NUMEROUS SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR TODAY IN MOST AREAS...RATHER THAN JUST FOR THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 356 AM EDT WED AUG 7 2013 THE ENTIRE FORECAST WILL BE PROGGED BY SUBTLE SHORTWAVES MOVING EASTWARD FROM THE ROCKIES AND GREAT PLAINS...AND IMPACTING KY OR SURROUNDING AREAS. FOR THE SHORT TERM...THE FOCUS WILL BE ON A SHORT WAVE THAT MODEL CONSENSUS HAS REACHING WESTERN KY BY 18Z TODAY...AND EASTERN KY IN THE EVENING AROUND 0Z. ANOTHER LARGER SHORTWAVE WILL THEN APPROACH WESTERN KY AND MUCH OF TN THE FOLLOWING AFTERNOON ON THURSDAY. BOTH OF THESE WAVES WILL TRANSLATE TO SURFACE INSTABILITY AND THE EXPECTATION OF CONVECTIVE DEVELOPMENT. STARTING WITH TODAY...A WARM FRONT THAT MOVED THROUGH LAST NIGHT HAS ALLOWED FOR STRONG WAA AND A VAST INCREASE IN THE HUMIDITY VALUES. WHILE EXPECTED CLOUD COVER TODAY WILL KEEP TEMPERATURES FROM RISING TO THEIR FULL POTENTIAL...DEW POINTS ON THE OTHER HAND WILL RISE TO THE LOW 70S...ALLOWING FOR HIGH HUMIDITY AND APPARENT TEMPERATURES IN THE MID AND UPPER 80S IN SOME LOCATIONS. THE SHORTWAVE APPROACHING FROM THE WEST WILL TRANSLATE TO A SURFACE LOW PRESSURE SYSTEM TO THE NORTH OVER THE UPPER GREAT LAKES. AS THIS SHORTWAVE AND ASSOCIATED LOW PRESSURE SYSTEM CONTINUE ON THEIR TREK NORTHEAST...IT WILL PULL A LARGE COLD FRONT SEWARD ACROSS MI/IN/IL/AND MO DURING THE AFTERNOON...NEARING THE OHIO VALLEY WEDNESDAY NIGHT. WITH THE VERY MOIST AND UNSTABLE ENVIRONMENT ALREADY AT PLAY DURING THE DAY TODAY...THE ISENTROPIC LIFT AHEAD OF THE APPROACHING FRONT WILL BE ENOUGH TO KICK START CONVECTION ACROSS THE AREA. WHILE MODELS ARE STILL SOMEWHAT LACKLUSTER ON THEIR SOLUTION AGREEMENT...WILL GO WITH THE CONSENSUS THAT BEST PRECIP POTENTIAL WILL BE IN THE FAR EASTERN PORTION OF THE CWA BETWEEN 15 AND 0Z TODAY. WITH GOOD DIRECTIONAL AND SPEED SHEAR...AS WELL AS MARGINAL CAPE VALUES...COULD SEE STORMS DEVELOP ACROSS THE ENTIRE CWA. WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN THE MID AND UPPER LEVELS...COULD SEE SOME POTENTIAL FOR STRONG WINDS AND SMALL HAIL DEVELOPMENT IN ADDITION TO SOME HEAVY DOWNPOURS. BEST CONVECTIVE ACTIVITY WILL DIE DOWN OVERNIGHT WITH LOSS OF DAYTIME HEATING...BUT AS COLD FRONT JUST TO OUR NORTH BECOMES NEARLY STATIONARY...THERE WILL BE ENOUGH INSTABILITY AND LIFT NEARBY TO PREVENT DROPPING POPS BELOW CHANCES. THIS WILL BE REINFORCED BY THE FACT THAT CLOUD COVER AND CONTINUED WARM AIR FILTERING IN FROM THE SOUTH WILL PREVENT LOWS FROM DROPPING BELOW 70 IN MANY LOCATIONS. THIS WILL RESULT IN A VERY SOUPY NIGHT WITH HUMIDITY VALUES RANGING FROM 90 TO 100 PERCENT ACROSS MUCH OF THE REGION. ANY LITTLE THING COULD BE ENOUGH TO INITIATE SOME SORT OF PRECIP IN SUCH AN ENVIRONMENT AS A RESULT. BY 12Z THURSDAY...THE NEXT SHORTWAVE TO IMPACT THE AREA WILL FIND ITSELF OVER MISSOURI AND NORTHERN ARKANSAS. AT THE SURFACE...THIS WILL BEGIN INTERACTING WITH THE STATIONARY SURFACE COLD FRONT AND THE DAYTIME INSTABILITY...BRINGING AN INCREASE OF CONVECTION ACROSS WESTERN KY IN THE MORNING...AND THEN ACROSS THE ENTIRE FRONTAL BOUNDARY BY AFTERNOON...WITH PRECIP CHANCES EXPECTED TO IMPACT FROM AS FAR WEST AS COLORADO...THEN POINTS EASTWARD...AND ACROSS THE ENTIRETY OF THE EASTERN SEABOARD. ONCE AGAIN...MODEL CONSENSUS IS PEGGING THE FAR EASTERN PORTIONS OF THE STATE FOR THE BEST QPF AND PRECIP POTENTIAL...THOUGH IN SUCH AN ENVIRONMENT SCT TO WIDESPREAD STORM DEVELOPMENT CAN BE EXPECTED JUST ABOUT ANYWHERE ACROSS THE REGION. CAPE VALUES THIS DAY WILL BE MUCH MORE SUBSTANTIAL IN THE EAST CENTRAL...WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN ALOFT DURING THE AFTERNOON HOURS. THE LATEST ECMWF IS ALSO SHOWING THAT WHILE LAPSE RATES WILL STILL NOT BE THAT IMPRESSIVE...THERE WILL BE A GOOD AREA OF QVECTOR CONVERGENCE THAT MOVES ACROSS THE STATE THURSDAY AFTERNOON/EVENING. ALL THINGS BEING FACTORED IN...LATEST NAM SOUNDINGS SUPPORT THE IDEA THAT WITH LITTLE IN THE WAY OF LAPSE RATES AND PWAT VALUES NEARING 2 INCHES IN SOME PLACES...WILL PROBABLY EXPECT MORE OF A HEAVY RAIN THREAT WITH THESE STORMS COMPARED TO TODAY. SOME ISOLATED STRONGER STORMS CAN NOT BE RULED OUT HOWEVER. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 356 AM EDT WED AUG 7 2013 THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN ALOFT FOR THE EXTENDED. LIKE LAST NIGHT...THE MAIN DIFFERENCES REVOLVE AROUND SHORTWAVES AND MESOSCALE FEATURES THAT ARE MORE DIFFICULT TO RESOLVE THIS FAR OUT. THE GENERAL PATTERN STARTS WITH A DOMINANT TROUGH OVER SOUTH CENTRAL CANADA NORTH OF FLAT RIDGING COVERING THE SOUTHERN TIER OF THE STATES. BETWEEN THESE...RELATIVELY FAST FLOW WILL BRING ENERGY FROM THE WEST COAST TO THE EAST PASSING THROUGH THE OHIO VALLEY. WHILE THE CORE OF THE NORTHERN TROUGH MOVES EAST BY EARLY SATURDAY THE TROUGH ITSELF WILL REFORM OVER THE WEEKEND AND ACTUALLY BUILD SOUTH TO ENCOMPASS THE GREAT LAKES OHIO VALLEY BY 00Z TUESDAY. OVER OUR AREA THIS EVOLUTION WILL BUCKLE THE INITIALLY ZONAL PATTERN INTO ONE OF NORTHWEST FLOW. THROUGH IT ALL...KENTUCKY WILL HAVE TO DEAL WITH PASSING WAVES OF MID LEVEL ENERGY ALONG WITH ANY THAT MAY BE CONVECTIVELY DRIVEN. THIS SHOULD MEAN AN LARGELY UNSETTLED PERIOD OF WEATHER. DUE TO THE GENERAL MODEL AGREEMENT...HAVE FAVORED A MODEL BLEND WITH A BIT OF A LEAN TOWARD THE 00Z ECMWF. SENSIBLE WEATHER WILL FEATURE AN EXTENDED PERIOD OF POTENTIALLY EXCESSIVE RAINS AS A FRONTAL BOUNDARY AND HIGHER THAN NORMAL PW AIR WILL REMAIN IN IN PLACE THROUGH THE WEEKEND. COMBINED WITH DAYTIME INSTABILITY...AND SOME UPPER LEVEL SUPPORT...EACH DAY COULD TURN OUT TO BE A WASHOUT WITH HEAVY RAIN FROM A COMPLEX OF SHOWERS AND THUNDERSTORMS. HOWEVER...SIMILAR TO TODAY...SOME OF THESE PARAMETERS MAY NOT COME TOGETHER AND A GOOD PORTION OF THE AREA COULD BE DRY DESPITE THE SET UP. AS SUCH...THE FORECAST WILL CONSIST OF HIGHER POP CHANCES DURING THE LATE AFTERNOON AND EARLY EVENING HOURS WITH A DIMINISHMENT AT NIGHT THROUGH SUNDAY. OF COURSE...ANY MCS ACTIVITY COULD EASILY EXTEND INTO THE NIGHT SO CANNOT GO DRY FOR THESE TIMES EITHER. UNFORTUNATELY...WITH THE POTENTIAL FOR MCS DEVELOPMENT THROUGH THE BULK OF THE EXTENDED...CONFIDENCE IS LOWER THAN NORMAL FOR FORECAST SPECIFICS ASIDE FROM THE ACKNOWLEDGMENT OF THE BUILT UP POSSIBILITIES. THEREFORE...THE FORECAST WILL CONSIST OF RATHER HIGH POPS THROUGH THE WEEKEND...WITH LESS OF A THREAT ON MONDAY AND TUESDAY IF THE NEW ECMWF IS RIGHT AND THE FRONT DROPS SOUTH. ALONG WITH THE HIGH POPS WILL GO COOLER THAN NORMAL TEMPS... THOUGH THE HIGH DEWPOINTS WILL MAKE IT FEEL SEVERAL DEGREES WARMER THAN ACTUAL AIR TEMPERATURE. BASED ON THE 00Z ECMWF...HIGH PRESSURE MAY BE ABLE TO PUSH IN AND SHOVE THE MORE HUMID AIR SOUTH FOR A GOOD PORTION OF THE UPCOMING WEEK. UNTIL THEN...THOUGH...WE WILL BE AWASH IN A MUGGY AIR MASS COMPLETE WITH MOST OF THE INGREDIENTS NEEDED FOR HEAVY RAINS. THE CR GRID LOAD CAME IN PRETTY GOOD FOR THIS CONVECTIVELY UNSETTLED SITUATION. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO TOWARD THE LATEST SPECIFICS FROM THE ECMWF. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS THROUGHOUT THE EXTENDED PERIOD GIVEN THE HIGH MOISTURE CONTENT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 655 AM EDT WED AUG 7 2013 SOMEWHAT OF AN UNSETTLED TAF FORECAST. MODEL GUIDANCE IS NOT IN FULL AGREEMENT ABOUT THE EXACT SET UP AND LOCATION OF TODAYS CONVECTIVE DEVELOPMENT...NOR IS THERE MUCH AGREEMENT ON THE CIGS THROUGHOUT THE DAY. BASED ON LATEST OBSERVATIONS...WHILE SOME LOCATIONS ARE STILL EXPERIENCING MVFR OR LOWER CONDITIONS...TAF SITES SEEM TO BE TAKING A UPWARD TREND. UNTIL ONSET OF PRECIP...AND PERHAPS EVEN AFTER...EXPECT CIGS TO REMAIN ABOVE VFR. THERE IS STILL A CHANCE HOWEVER...THAT AS WE GO INTO THE DAYTIME HOURS SOME OF THE CONVECTIVE DEVELOPMENT COULD LOWER TO MVFR. PRECIP CHANCES WILL LESSON WITH LOSS OF DAYTIME HEATING THIS EVENING...BUT VCSH WILL STILL BE WARRANTED. WHILE SOME BR DEVELOPMENT IS POSSIBLE AFTER THIS POINT...CLOUD COVER COULD WORK TO INHIBIT ITS DEVELOPMENT...SO WAS NOT CONFIDENT ENOUGH TO INCLUDE IN TAFS THIS FAR OUT IN THE PERIOD. MUCH LIKE LAST NIGHT...FOG WILL LIKELY OCCUR IN A FEW ISOLATED SPOTS AND REMAIN OUT OF THE TAF SITES. BASED ON LOWERING CIGS THROUGHOUT THE NIGHT LAST NIGHT...COULD ALSO EXPECT A SIMILAR SITUATION TONIGHT. BUT ONCE AGAIN...WITH SUCH LOW MODEL CONFIDENCE AND BEING THIS FAR OUT...CHOSE NOT TO INCLUDE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...JMW LONG TERM...GREIF AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
957 AM EDT WED AUG 7 2013 .UPDATE... ISSUED AT 956 AM EDT WED AUG 7 2013 NDFD AND ASSOCIATED PRODUCTS...INCLUDING ZFP HAVE BEEN UPDATED. THE NEAR TERM MODELS ARE NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...AND AS SUCH THIS THROWS DOUBT INTO THE NEAR TERM GUIDANCE FOR THE REST OF THE DAY INTO TONIGHT. THE 11Z HRRR SHOWED THE DEVELOPMENT OF THE CONVECTION EARLY THIS MORNING BUT QUICKLY HAD IT DIE AWAY BEFORE BRINGING AN ORGANIZED BAND OF CONVECTION ACROSS THE AREA FROM LATE MORNING INTO EARLY AFTERNOON WITH ANOTHER ROUND OF ORGANIZED CONVECTION FROM LATE AFTERNOON INTO THE EVENING. THE 12Z HRRR IS JUST COMING IN...AND STILL NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...BUT IS LEANING TOWARDS MORE DISORGANIZATION IN THE CONVECTION FOR THIS AFTERNOON. THERE WILL BE CONSIDERABLE DEBRIS CLOUDINESS ACROSS THE AREA TODAY...BUT EXPECT SOME BREAKS IN THE CLOUDS IN THE WAKE OF THE SHOWERS AND THUNDERSTORMS THAT OCCUR THIS MORNING. THIS WOULD ALLOW ADDITIONAL DESTABILIZATION WITH MORE AFTERNOON HEATING. WHERE BREAKS HAVE OCCURRED IN CENTRAL KY TEMPERATURES HAVE JUMPED INTO THE UPPER 70S AND AS SUCH WILL INCREASE AFTERNOON MAXIMUM TEMPERATURES SEVERAL DEGREES. WITH NUMEROUS SHOWERS ALREADY OCCURRING ACROSS THE AREA HAVE INCREASED RAIN CHANCES FOR THIS MORNING IN ALL BUT THE FAR NORTH...YIELDING NUMEROUS SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR TODAY IN MOST AREAS...RATHER THAN JUST FOR THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 356 AM EDT WED AUG 7 2013 THE ENTIRE FORECAST WILL BE PROGGED BY SUBTLE SHORTWAVES MOVING EASTWARD FROM THE ROCKIES AND GREAT PLAINS...AND IMPACTING KY OR SURROUNDING AREAS. FOR THE SHORT TERM...THE FOCUS WILL BE ON A SHORT WAVE THAT MODEL CONSENSUS HAS REACHING WESTERN KY BY 18Z TODAY...AND EASTERN KY IN THE EVENING AROUND 0Z. ANOTHER LARGER SHORTWAVE WILL THEN APPROACH WESTERN KY AND MUCH OF TN THE FOLLOWING AFTERNOON ON THURSDAY. BOTH OF THESE WAVES WILL TRANSLATE TO SURFACE INSTABILITY AND THE EXPECTATION OF CONVECTIVE DEVELOPMENT. STARTING WITH TODAY...A WARM FRONT THAT MOVED THROUGH LAST NIGHT HAS ALLOWED FOR STRONG WAA AND A VAST INCREASE IN THE HUMIDITY VALUES. WHILE EXPECTED CLOUD COVER TODAY WILL KEEP TEMPERATURES FROM RISING TO THEIR FULL POTENTIAL...DEW POINTS ON THE OTHER HAND WILL RISE TO THE LOW 70S...ALLOWING FOR HIGH HUMIDITY AND APPARENT TEMPERATURES IN THE MID AND UPPER 80S IN SOME LOCATIONS. THE SHORTWAVE APPROACHING FROM THE WEST WILL TRANSLATE TO A SURFACE LOW PRESSURE SYSTEM TO THE NORTH OVER THE UPPER GREAT LAKES. AS THIS SHORTWAVE AND ASSOCIATED LOW PRESSURE SYSTEM CONTINUE ON THEIR TREK NORTHEAST...IT WILL PULL A LARGE COLD FRONT SEWARD ACROSS MI/IN/IL/AND MO DURING THE AFTERNOON...NEARING THE OHIO VALLEY WEDNESDAY NIGHT. WITH THE VERY MOIST AND UNSTABLE ENVIRONMENT ALREADY AT PLAY DURING THE DAY TODAY...THE ISENTROPIC LIFT AHEAD OF THE APPROACHING FRONT WILL BE ENOUGH TO KICK START CONVECTION ACROSS THE AREA. WHILE MODELS ARE STILL SOMEWHAT LACKLUSTER ON THEIR SOLUTION AGREEMENT...WILL GO WITH THE CONSENSUS THAT BEST PRECIP POTENTIAL WILL BE IN THE FAR EASTERN PORTION OF THE CWA BETWEEN 15 AND 0Z TODAY. WITH GOOD DIRECTIONAL AND SPEED SHEAR...AS WELL AS MARGINAL CAPE VALUES...COULD SEE STORMS DEVELOP ACROSS THE ENTIRE CWA. WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN THE MID AND UPPER LEVELS...COULD SEE SOME POTENTIAL FOR STRONG WINDS AND SMALL HAIL DEVELOPMENT IN ADDITION TO SOME HEAVY DOWNPOURS. BEST CONVECTIVE ACTIVITY WILL DIE DOWN OVERNIGHT WITH LOSS OF DAYTIME HEATING...BUT AS COLD FRONT JUST TO OUR NORTH BECOMES NEARLY STATIONARY...THERE WILL BE ENOUGH INSTABILITY AND LIFT NEARBY TO PREVENT DROPPING POPS BELOW CHANCES. THIS WILL BE REINFORCED BY THE FACT THAT CLOUD COVER AND CONTINUED WARM AIR FILTERING IN FROM THE SOUTH WILL PREVENT LOWS FROM DROPPING BELOW 70 IN MANY LOCATIONS. THIS WILL RESULT IN A VERY SOUPY NIGHT WITH HUMIDITY VALUES RANGING FROM 90 TO 100 PERCENT ACROSS MUCH OF THE REGION. ANY LITTLE THING COULD BE ENOUGH TO INITIATE SOME SORT OF PRECIP IN SUCH AN ENVIRONMENT AS A RESULT. BY 12Z THURSDAY...THE NEXT SHORTWAVE TO IMPACT THE AREA WILL FIND ITSELF OVER MISSOURI AND NORTHERN ARKANSAS. AT THE SURFACE...THIS WILL BEGIN INTERACTING WITH THE STATIONARY SURFACE COLD FRONT AND THE DAYTIME INSTABILITY...BRINGING AN INCREASE OF CONVECTION ACROSS WESTERN KY IN THE MORNING...AND THEN ACROSS THE ENTIRE FRONTAL BOUNDARY BY AFTERNOON...WITH PRECIP CHANCES EXPECTED TO IMPACT FROM AS FAR WEST AS COLORADO...THEN POINTS EASTWARD...AND ACROSS THE ENTIRETY OF THE EASTERN SEABOARD. ONCE AGAIN...MODEL CONSENSUS IS PEGGING THE FAR EASTERN PORTIONS OF THE STATE FOR THE BEST QPF AND PRECIP POTENTIAL...THOUGH IN SUCH AN ENVIRONMENT SCT TO WIDESPREAD STORM DEVELOPMENT CAN BE EXPECTED JUST ABOUT ANYWHERE ACROSS THE REGION. CAPE VALUES THIS DAY WILL BE MUCH MORE SUBSTANTIAL IN THE EAST CENTRAL...WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN ALOFT DURING THE AFTERNOON HOURS. THE LATEST ECMWF IS ALSO SHOWING THAT WHILE LAPSE RATES WILL STILL NOT BE THAT IMPRESSIVE...THERE WILL BE A GOOD AREA OF QVECTOR CONVERGENCE THAT MOVES ACROSS THE STATE THURSDAY AFTERNOON/EVENING. ALL THINGS BEING FACTORED IN...LATEST NAM SOUNDINGS SUPPORT THE IDEA THAT WITH LITTLE IN THE WAY OF LAPSE RATES AND PWAT VALUES NEARING 2 INCHES IN SOME PLACES...WILL PROBABLY EXPECT MORE OF A HEAVY RAIN THREAT WITH THESE STORMS COMPARED TO TODAY. SOME ISOLATED STRONGER STORMS CAN NOT BE RULED OUT HOWEVER. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 356 AM EDT WED AUG 7 2013 THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN ALOFT FOR THE EXTENDED. LIKE LAST NIGHT...THE MAIN DIFFERENCES REVOLVE AROUND SHORTWAVES AND MESOSCALE FEATURES THAT ARE MORE DIFFICULT TO RESOLVE THIS FAR OUT. THE GENERAL PATTERN STARTS WITH A DOMINANT TROUGH OVER SOUTH CENTRAL CANADA NORTH OF FLAT RIDGING COVERING THE SOUTHERN TIER OF THE STATES. BETWEEN THESE...RELATIVELY FAST FLOW WILL BRING ENERGY FROM THE WEST COAST TO THE EAST PASSING THROUGH THE OHIO VALLEY. WHILE THE CORE OF THE NORTHERN TROUGH MOVES EAST BY EARLY SATURDAY THE TROUGH ITSELF WILL REFORM OVER THE WEEKEND AND ACTUALLY BUILD SOUTH TO ENCOMPASS THE GREAT LAKES OHIO VALLEY BY 00Z TUESDAY. OVER OUR AREA THIS EVOLUTION WILL BUCKLE THE INITIALLY ZONAL PATTERN INTO ONE OF NORTHWEST FLOW. THROUGH IT ALL...KENTUCKY WILL HAVE TO DEAL WITH PASSING WAVES OF MID LEVEL ENERGY ALONG WITH ANY THAT MAY BE CONVECTIVELY DRIVEN. THIS SHOULD MEAN AN LARGELY UNSETTLED PERIOD OF WEATHER. DUE TO THE GENERAL MODEL AGREEMENT...HAVE FAVORED A MODEL BLEND WITH A BIT OF A LEAN TOWARD THE 00Z ECMWF. SENSIBLE WEATHER WILL FEATURE AN EXTENDED PERIOD OF POTENTIALLY EXCESSIVE RAINS AS A FRONTAL BOUNDARY AND HIGHER THAN NORMAL PW AIR WILL REMAIN IN IN PLACE THROUGH THE WEEKEND. COMBINED WITH DAYTIME INSTABILITY...AND SOME UPPER LEVEL SUPPORT...EACH DAY COULD TURN OUT TO BE A WASHOUT WITH HEAVY RAIN FROM A COMPLEX OF SHOWERS AND THUNDERSTORMS. HOWEVER...SIMILAR TO TODAY...SOME OF THESE PARAMETERS MAY NOT COME TOGETHER AND A GOOD PORTION OF THE AREA COULD BE DRY DESPITE THE SET UP. AS SUCH...THE FORECAST WILL CONSIST OF HIGHER POP CHANCES DURING THE LATE AFTERNOON AND EARLY EVENING HOURS WITH A DIMINISHMENT AT NIGHT THROUGH SUNDAY. OF COURSE...ANY MCS ACTIVITY COULD EASILY EXTEND INTO THE NIGHT SO CANNOT GO DRY FOR THESE TIMES EITHER. UNFORTUNATELY...WITH THE POTENTIAL FOR MCS DEVELOPMENT THROUGH THE BULK OF THE EXTENDED...CONFIDENCE IS LOWER THAN NORMAL FOR FORECAST SPECIFICS ASIDE FROM THE ACKNOWLEDGMENT OF THE BUILT UP POSSIBILITIES. THEREFORE...THE FORECAST WILL CONSIST OF RATHER HIGH POPS THROUGH THE WEEKEND...WITH LESS OF A THREAT ON MONDAY AND TUESDAY IF THE NEW ECMWF IS RIGHT AND THE FRONT DROPS SOUTH. ALONG WITH THE HIGH POPS WILL GO COOLER THAN NORMAL TEMPS... THOUGH THE HIGH DEWPOINTS WILL MAKE IT FEEL SEVERAL DEGREES WARMER THAN ACTUAL AIR TEMPERATURE. BASED ON THE 00Z ECMWF...HIGH PRESSURE MAY BE ABLE TO PUSH IN AND SHOVE THE MORE HUMID AIR SOUTH FOR A GOOD PORTION OF THE UPCOMING WEEK. UNTIL THEN...THOUGH...WE WILL BE AWASH IN A MUGGY AIR MASS COMPLETE WITH MOST OF THE INGREDIENTS NEEDED FOR HEAVY RAINS. THE CR GRID LOAD CAME IN PRETTY GOOD FOR THIS CONVECTIVELY UNSETTLED SITUATION. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO TOWARD THE LATEST SPECIFICS FROM THE ECMWF. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS THROUGHOUT THE EXTENDED PERIOD GIVEN THE HIGH MOISTURE CONTENT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 655 AM EDT WED AUG 7 2013 SOMEWHAT OF AN UNSETTLED TAF FORECAST. MODEL GUIDANCE IS NOT IN FULL AGREEMENT ABOUT THE EXACT SET UP AND LOCATION OF TODAYS CONVECTIVE DEVELOPMENT...NOR IS THERE MUCH AGREEMENT ON THE CIGS THROUGHOUT THE DAY. BASED ON LATEST OBSERVATIONS...WHILE SOME LOCATIONS ARE STILL EXPERIENCING MVFR OR LOWER CONDITIONS...TAF SITES SEEM TO BE TAKING A UPWARD TREND. UNTIL ONSET OF PRECIP...AND PERHAPS EVEN AFTER...EXPECT CIGS TO REMAIN ABOVE VFR. THERE IS STILL A CHANCE HOWEVER...THAT AS WE GO INTO THE DAYTIME HOURS SOME OF THE CONVECTIVE DEVELOPMENT COULD LOWER TO MVFR. PRECIP CHANCES WILL LESSON WITH LOSS OF DAYTIME HEATING THIS EVENING...BUT VCSH WILL STILL BE WARRANTED. WHILE SOME BR DEVELOPMENT IS POSSIBLE AFTER THIS POINT...CLOUD COVER COULD WORK TO INHIBIT ITS DEVELOPMENT...SO WAS NOT CONFIDENT ENOUGH TO INCLUDE IN TAFS THIS FAR OUT IN THE PERIOD. MUCH LIKE LAST NIGHT...FOG WILL LIKELY OCCUR IN A FEW ISOLATED SPOTS AND REMAIN OUT OF THE TAF SITES. BASED ON LOWERING CIGS THROUGHOUT THE NIGHT LAST NIGHT...COULD ALSO EXPECT A SIMILAR SITUATION TONIGHT. BUT ONCE AGAIN...WITH SUCH LOW MODEL CONFIDENCE AND BEING THIS FAR OUT...CHOSE NOT TO INCLUDE. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...JMW LONG TERM...GREIF AVIATION...JMW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1048 AM EDT WED AUG 7 2013 .SYNOPSIS... A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VALLEY WILL LEAD TO SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER MAINLY ALONG AND WEST OF THE INTERSTATE 81 CORRIDOR BY THIS AFTERNOON. RAIN AND THUNDER CHANCES WILL INCREASE AREAWIDE BEGINNING TONIGHT AS A LONG AWAITED COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL THEN STALL ACROSS THE AREA BY THURSDAY MORNING KEEPING THE THREAT FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1045 AM UPDATE... CONVECTION IS BEGINNING TO DVLP ON GUST FRONT OVR NRN OHIO AT THIS TIME. MCS NOW OVR SRN ONTARIO/MICHIGAN HAS DVLPD AHD OF MAIN UPR WV AND THIS SHUD BEGIN TO FIZZLE THRU THE DAY. SHUD ALSO HEAD OFF JUST TO THE NORTH OF CWA PER LATEST HIRES MODELS IN 1000-500MB THICKNESS FIELDS. MAIN QUESTION IS WHAT KIND OF REMNANT WV THIS MCS CAN DISLODGE TWD THE FA THIS AFTN. EML PRESENT ON 12Z ILN SOUNDING EXPECTED TO SPREAD INTO WRN ZONES THIS AFTN. IF ANYTHING CAN DVLP THIS AFTN WHICH LATEST MODELS ARE HOLDING QPF OFF UNTIL AFT 00Z, WITH EXCEPTION OF HRRR AND RAP, POTENTIAL EXISTS FOR ISOLD SVR. CAPES FCST TO BE ON THE ORDER OF 1000 J/KG AND BULK SHEAR VALUES OF 20-30KTS IN THE 0-1 AND 0-3KM LAYERS WITH QUITE A BIT OF DIRECTIONAL SHEAR PRESENT PER KELM RAP SNDGS. SEE NO REASON TO CHG POP FCST AT THIS TIME WITH SCTD SHOWERS AND ISOLD THUNDER ACRS WRN ZONES AFT 18Z AND THEN INCRSG TO SCTD THUNDER LATE THIS AFTN. WL CONTINUE TO MONITOR FOR ANY CHGS TO CURRENT THINKING. ALSO RMVD MENTION OF ISOLD SHOWERS ACRS SRN ZONES IN MARINE LYR FOR THE NEXT COUPLE OF HOURS. WITH EXTENSIVE CLD CVR ACRS THE REGION AND TEMPS ONLY RISING 1-2 DEGREES OVR THE PAST HR HV LEFT MAX TEMP FCST UNCHANGED. MAX TEMPS SHUD RISE TO FCST VALUES IF BREAKS CAN DVLP IN CLDS. FOR NOW, WILL JUST SIT AND WAIT BFR MAKING ANY CHGS TO TEMP/POP/WX GRIDS. 625 AM UPDATE... TOOK THE LIBERTY OF INCREASING HIGH TEMPS A DEGREE OR TWO FOR LATER TODAY AS LOW STRATUS UP HERE AT THE AIRPORT LOOKS PRETTY THIN. AS A RESULT...A LITTLE MORE SUNSHINE IS EXPECTED WHICH SHOULD HELP IN THE DIURNAL HEATING DEPARTMENT. NO OTHER CHANGES NEEDED AT THE PRESENT TIME. PREVIOUS NEAR TERM DISCUSSION... EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING LOW STRATUS CONTINUING TO WORK NORTH INTO THE FCST AREA AS SOUTHERLY RETURN FLOW INCREASES ON THE BACKSIDE OF HIGH PRESSURE NOW POSITIONED OF THE MID-ATLANTIC COAST. THE PRESENCE OF THESE CLOUDS MAKES TODAY/S FORECAST ANYTHING BUT EASY AS CLOUD COVER WILL HAVE SIGNIFICANT IMPACTS ON BOTH THE DESTABILIZATION POTENTIAL AND HIGH TEMP FORECASTS LATER TODAY. IN ANY EVENT ...UPPER-LEVEL PATTERN REMAINS DOMINATED BY A BROAD UPPER LOW WHICH CONTINUES TO SPIN JUST SOUTH OF HUDSON BAY THIS MORNING...WITH DEVELOPING DIFFLUENT FLOW DOWNSTREAM ACROSS THE CENTRAL AND EASTERN GREAT LAKES. EMBEDDED WITHIN THIS FLOW IS A FAIRLY DECENT SHORTWAVE AND VERY DISCERNIBLE MCS WHICH CONTINUES TO WORK THROUGH WESTERN/CENTRAL MICHIGAN THIS MORNING. IN FACT...RADAR APPEARANCE OF THIS MCS IS VERY IMPRESSIVE WITH ALL INDICATIONS SUGGESTING THIS FEATURE HAS ORGANIZED INTO A WELL- DEFINED DERECHO WITH WIDESPREAD WIND DAMAGE REPORTED AS FAR WEST AS SOUTHEASTERN NORTH DAKOTA. CURRENT THINKING IS THIS FEATURE WILL WEAKEN WITH FURTHER EASTWARD PROGRESS INTO SOUTHERN ONTARIO AS ATMOSPHERE DOWNSTREAM REMAINS MUCH MORE STABLE. LINGERING MCV/SHORTWAVE ENERGY LIKELY TO PASS JUST TO OUR NORTH LATER THIS MORNING AS FLOW UPPER FLOW BECOMES MORE SOUTHWEST DOWNSTREAM OVER THE EASTERN LAKES. MOVING INTO TODAY...FCST MODELS CONTINUE TO HINT AT DEVELOPING SHWRS/ISO STORMS AS DIURNAL HEATING COMBINES WITH THE PASSING OF A FEW WEAK SHORTWAVES. THAT SAID...MODEL INSTABILITY REMAINS ANYTHING BUT IMPRESSIVE WITH BOTH GFS AND NAM SUGGESTING MLCAPE VALUES OF MAYBE A FEW HUNDRED JOULES AT BEST...MAINLY ALONG AND WEST OF THE I-81 CORRIDOR. CONSIDERING FORCING REMAINS FAIRLY WEAK DESPITE WHAT APPEARS TO BE A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VLY...AREAL COVERAGE OF SHWRS/STORMS LIKELY TO REMAIN IN THE ISO-SCT CATEGORY. FOR NOW HAVE MAINTAINED THIS TREND FROM PREVIOUS FORECASTS WITH THUNDER MENTION MAINLY CONFINED TO AREAS OUTLINED ABOVE. TEMP FORECAST ANYTHING BUT EASY DUE TO LOW STRATUS WHICH SOME MODELS SUGGEST WILL BE WITH US FOR A GOOD PORTION OF THE HEATING CYCLE. WITH THIS BEING THE CASE...HAVE KEPT HIGHEST VALUES (UPPER 70S) CONFINED TO THE IMMEDIATE LAKE PLAIN...WITH COOLER VALUES FROM THE FINGER LAKES AND POINTS SOUTH. OBVIOUSLY A FEW BREAKS HERE AND THERE MAY YIELD WARMER VALUES THAN CURRENTLY FORECAST...ESPECIALLY FOR TWIN TIERS AND FINGER LAKES AREAS. BY TONIGHT...COLD FRONT EXPECTED TO DROP SOUTH ACROSS THE FCST AREA AFTER 00Z THIS EVENING. AS THIS OCCURS...EXPECT SHWRS/STORMS TO INCREASE WITH TIME AND THUS HAVE MAINTAINED NUMEROUS MENTION FOR THE REGION DURING THE ENTIRE PERIOD. OVERNIGHT LOWS SHOULD BE FAIRLY WARM WITH CLOUDS/PRECIP IN THE VICINITY WITH VALUES LARGELY FALLING INTO THE LOWER TO MIDDLE 60S AREAWIDE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AFOREMENTIONED FRONT TO STALL ACROSS THE FCST AREA ON THURSDAY WITH CONTINUES CHANCES FOR SHWRS/STORMS THROUGH MUCH OF THE DAYLIGHT HRS. FCST MODELS TO HINT AT BETTER INSTABILITY GENERATION DURING THE DAY WITH BOTH GFS AND NAM OFFERING ROUGHLY 500-1000 J/KG. THIS COMBINED WITH 0-6 KM BULK SHEAR VECTORS OF 30-40 KTS SUGGESTS THAT SOME SEVERE WILL BE POSSIBLE IF STORMS BECOME ORGANIZED. CURRENT SPC DAY 2 OUTLOOK HIGHLIGHTS OUR AREA WITH A "SEE TEXT" FOR THE POSSIBILITY OF ORGANIZED MULTICELLS OFFERING AN ISOLATED WIND/HAIL THREAT. AS HAS BEEN THE CASE IN RECENT DAYS...OVERALL SYNOPTIC FORCING LOOKS FAIRLY WEAK DESPITE FRONTAL BOUNDARY REMAINING POSITIONED OVER THE AREA. BEYOND THIS...SHWRS/STORMS REMAIN IN THE FCST THROUGH FRI WITH INDICATIONS SUGGESTING BEST FORCING WILL ARRIVE FRI NGT/EARLY SAT AS HUDSON BAY UPPER LOW BEGINS TO SHIFT EAST AND TAKE ON A NEGATIVE TILT WITH TIME. AS THIS OCCURS...MODELS SHOW A SFC LOW LIFTING NORTH FROM THE OHIO VLY WITH A PRETTY GOOD SLUG OF MOISTURE AS PWAT VALUES EXCEED 2" BY 00Z SAT. SOME AREAS MAY SEE A BRIEF PERIOD OF MODERATE TO HEAVY RAIN FRI NGT/EARLY SAT BUT MAIN AREA SHOULD MOVE FAIRLY QUICKLY TO THE NORTHEAST...THUS NO SIGNIFICANT IMPACTS EXPECTED. && .LONG TERM /SATURDAY THROUGH TUESDAY/... 200 PM UPDATE... FRIDAY NIGHT WE WILL BE IN THE PROCESS OF MOVING A COLD FRONT THROUGH OUR AREA. SOME SHOWERS MAY LINGER THROUGH FRIDAY NIGHT...ESPECIALLY ACROSS NEPA. A MARKED PUNCH OF DRIER AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL RACE OUT OF THE GREAT LAKES AND BE WITH US BY 12Z SATURDAY. THIS WILL END ANY SHOWER THREAT AND DRY US OUT FOR SATURDAY. HIGH PRESSURE WILL CONTROL OUR WEATHER SUNDAY INTO EARLY NEXT WEEK WITH A BEAUTIFUL STRETCH OF WEATHER. IT WILL REMAIN BELOW AVERAGE WITH 850 TEMPS IN THE LOWER TEENS SUPPORTING HIGHS IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 40S AND 50S. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... UPDATED AT 630 AM... PATCHY MVFR CIGS WILL GIVE WAY TO VFR CONDITIONS BY 14Z. VFR CONDITIONS WILL PERSIST THROUGH MOST OF THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON THROUGH THIS EVENING WILL BE ACCOMPANIED BY SCATTERED BRIEF PERIODS OF MVFR CIGS AND VSBYS. WINDS WILL BE LIGHT AND VARIABLE THIS MORNING BECOMING SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15 KTS TONIGHT. OUTLOOK... THU AND THU NGT...MVFR IN SHRA AND TSRA. FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH. SAT AND SUN...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...CMG/PVN NEAR TERM...CMG/PVN SHORT TERM...CMG LONG TERM...HEDEN AVIATION...MSE/TAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1019 AM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA MONDAY AND TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF INTERSTATE 95. THE MORNING SOUNDINGS CONTINUE TO BE RATHER DRY WITH THE NEWPORT SOUNDINGS PRECIPITABLE WATER JUST BE LOW THE 50TH PERCENTILE. THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME OF PRODUCING ANY CONVECTION AND THE 12 UTC HRRR IS SHOWING ISOLATED CONVECTION AT 18 UTC BUT IT IS SHORT LIVED AND MAINLY WEST OF A BURGAW TO ANDREWS LINE. AT THIS TIME CONFIDENCE IS LOW OF A SLIGHT CHANCE OF CONVECTION SO WILL CONTINUE WITH THE CURRENT FORECAST OF LESS THAN A 15 PERCENT CHANCE OF MEASURABLE PRECIPITATION. FROM PREVIOUS DISCUSSION...FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH LOWS 69-74...WARMEST AT THE COAST. MODELS ARE HINTING AT THE SOUTHEAST FLOW ALONG THE COAST POTENTIALLY YIELDING SOME MARINE SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A TREND OF INCREASING POPS TOWARD SUNRISE THURSDAY AT THE BEACHES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE SEA-BREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS UNCHANGED FOR THE MOST PART. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY. PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON HOURS...DIMINISHING TONIGHT. SOME LIGHT FOG IS POSSIBLE AFTER 08Z...MAINLY INLAND. EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM WEDNESDAY...NORTHEAST TO EAST WINDS THIS MORNING WITH SPEEDS UNDER 10 KNOTS. THIS IS PRODUCING SEAS OF 2 TO 3 FEET. WINDS ARE STILL ON TRACK TO VEER TO THE SOUTHEAST BY AFTERNOON. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS. THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN KNOTS. WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT SEAS OF 2-3 FEET. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DRH SHORT TERM...SHK LONG TERM...SHK AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
740 AM EDT WED AUG 7 2013 .SYNOPSIS... A MOIST SOUTHERLY RETURN FLOW WILL PREVAIL ACROSS THE REGION THROUGH MID TO LATE WEEK...ON THE WESTERN PERIPHERY OF AN OFFSHORE RIDGE. A COLD FRONT WILL MOVE INTO THE REGION BY THIS WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 255 AM WEDNESDAY... PERSISTENCE WILL DOMINATE THE FORECAST TODAY AS SOUTHERLY LOW-LEVEL FLOW CONTINUES BENEATH WEST-NORTHWESTERLY FLOW ALOFT. WEAK WARM ADVECTION...MASS CONVERGENCE ALONG THE HIGHER TERRAIN... AND MOISTURE POOLING OVER WESTERN WILL PROMOTE SCATTERED SHOWERS BY THIS AFTERNOON. THE MOST RECENT HRRR RUN INDICATES SHOWERS NEAR THE TRIAD BY AROUND NOON. DESPITE DEWPOINTS IN THE MID AND UPPER 60S...WIDESPREAD CLOUD COVER...BOTH AT LOW-LEVELS AND ALOFT...ALONG WITH WEAK MID-LEVEL LAPSE RATES WILL KEEP MLCAPE AT 500 J/KG OR LESS EAST OF THE MOUNTAINS. A WEAK UPPER DISTURBANCE LEFT OVER FROM CONVECTION OVER MISSOURI IS CROSSING THE TN VALLEY THIS MORNING...BUT THE MODEL CONSENSUS IS FOR THE DISTURBANCE TO CONTINUE TO WEAKEN AS IT DROPS EAST-SOUTHEAST TOWARD GEORGIA AND SC. THUS..THE CHANCE OF STORMS IS RATHER LOW TODAY. FORECAST SOUNDINGS SUGGEST A FEW MORE BREAKS IN CLOUD COVER TODAY...BUT THE STRATUS OVER THE WESTERN PIEDMONT THIS MORNING AND HIGH CLOUDS DRIFTING OVERHEAD SHOULD HOLD TEMPS DOWN OVER THE WESTERN CWA...WITH 82-87 A GOOD COMPROMISE OF STATISTICAL GUIDANCE. TONIGHT IN THE ABSENCE OF ANY SIGNIFICANT FORCING ALOFT...SHOWERS SHOULD BE DIURNAL IN NATURE AND THE OVERNIGHT PERIOD DRY. STRATUS IS LIKELY AGAIN OVER THE WESTERN PIEDMONT...WITH LOWS IN THE UPPER 60S TO AROUND 70...WARMEST IN THE WEST. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM WEDNESDAY... THURSDAY AND THURSDAY NIGHT... HEIGHTS ALOFT ARE EXPECTED TO RISE SLIGHTLY ON THURSDAY AS THE UPPER RIDGE OVER THE SOUTHERN US BRIEFLY EXPANDS EASTWARD AND A SHORTWAVE BEGINS TO DIVE SOUTH OUT OF CENTRAL CANADA. PW VALUES WILL CONTINUE TO CREEP UP TO ABOVE 1.75`...BUT THE LACK OF FORCING AND AFOREMENTIONED RIDGING ALOFT SHOULD KEEP CONVECTION CONFINED TO THE SEABREEZE AND HIGHER TERRAIN. HIGHS IN THE MID TO UPPER 80S. LOWS THURSDAY NIGHT AROUND 70. -SMITH FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN MIDLEVEL VORTEX MOVES FROM CENTRAL ONTARIO OVER QUEBEC THROUGH FRI NIGHT WITH THE TRAILING BROAD TROUGH AXIS SHIFTING ACROSS THE GREAT LAKES INTO THE MIDATLANTIC AND NORTHEAST. THE ASSOCIATED SURFACE COLD FRONT BECOMES MORE EAST-WEST ORIENTED TO OUR NORTH WHILE HEIGHTS ALOFT RISE SLIGHTLY OVER NC. THE UPPER LEVEL ANTICYCLONE TO OUR SOUTH SHIFTS EASTWARD... AND THE STRENGTHENING WESTERLY FLOW AT JET LEVEL INDUCES INCREASING UPPER DIVERGENCE OVER VA INTO CENTRAL NC (ALTHOUGH MODELS DIFFER ON THE DETAILS)... AND THE STRENGTHENING AND VEERING LOW LEVEL FLOW (WITH THE 850 MB TROUGH PASSAGE) RESULTS IN STRENGTHENING MOISTURE TRANSPORT PARTICULARLY OVER NORTH CENTRAL AND NORTHEAST NC IN THE AFTERNOON THROUGH EVENING. MODERATE INSTABILITY (MLCAPE OF 1200-1800 J/KG) IS EXPECTED FRI AFTERNOON/EVENING BUT WITH POOR DEEP-LAYER SHEAR UNDER 20 KTS FOR MUCH OF THE DAY...ALTHOUGH THIS DOES IMPROVE SLIGHTLY OVERNIGHT AS MIDLEVEL WINDS STRENGTHEN NEAR THE NC/VA BORDER... WHILE SOME WEAK ELEVATED INSTABILITY LINGERS. GIVEN THIS COMBINATION OF INSTABILITY AND WEAK DYNAMIC FORCING FOR ASCENT WITH HIGH PW AT OR ABOVE 2.0 INCHES... AT LEAST A 50% COVERAGE OF SHOWERS/STORMS IS JUSTIFIED ACROSS THE WRN/NRN CWA WHERE MOISTURE TRANSPORT IS HIGHEST ALONG THE LEE SURFACE TROUGH... WITH A LITTLE LOWER CHANCE OVER THE SOUTHEAST CLOSER TO THE MIDLEVEL ANTICYCLONE CENTER. HIGHS 88-92. RAIN CHANCES SHOULD WIND DOWN BY LATE EVENING AS LOW LEVEL FLOW BECOMES MORE WESTERLY WITH DOWNSLOPE DRYING AND INCREASING STABILITY AFTER SUNSET... BUT THE ANOMALOUSLY HIGH MOISTURE CONTENT OF THE COLUMN SUPPORTS A CONTINUED THREAT OF ISOLATED SHOWERS OVERNIGHT. LOWS 70-74. FOR SATURDAY/SATURDAY NIGHT: THIS STILL LOOKS LIKE THE WETTEST DAY OF THIS FORECAST. HEIGHTS ALOFT BEGIN TO FALL OVER THE APPALACHIANS INTO CENTRAL NC AS ENERGY TRACKS INTO THE TROUGH BASE... FROM ONTARIO ACROSS THE OH VALLEY... WHILE DEEP MOISTURE PERSISTS OVER THE LINGERING LEE TROUGH OVER CENTRAL NC AHEAD OF THE APPROACHING LARGE SCALE FRONTAL ZONE TO OUR NORTH AND NORTHWEST. THE INCREASING DPVA... HIGH LOW-LEVEL THETA-E... HIGH PW... AND MODERATE INSTABILITY SUPPORTS A 50-60% CHANCE OF SHOWERS/STORMS... HIGHEST IN THE NW AND NORTHERN CWA WHERE UPPER DIVERGENCE WILL BE GREATEST IN THE RIGHT ENTRANCE REGION OF THE 80-100 KT JET CORE OVER/OFF NEW ENGLAND. HIGHS 88-93 AS THE ABOVE-NORMAL THICKNESSES ARE TEMPERED BY ABUNDANT CLOUDINESS AND THE EARLY ONSET OF CONVECTION. LOWS AGAIN 70-74 WITH PLENTY OF CLOUDS AND A FEW RESIDUAL SHOWERS OVERNIGHT. -GIH && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 250 AM WEDNESDAY... THE AMPLIFICATION OF THE EASTERN US TROUGH CONTINUES INTO EARLY NEXT WEEK AS A SECONDARY VORTEX DROPS DOWN THROUGH ERN ONTARIO/JAMES BAY. MODELS INDICATE THAT THE SURFACE FRONT WILL SINK SLOWLY SE INTO FAR NRN AND WRN NC SUNDAY/SUNDAY NIGHT. WITH INCREASING DYNAMIC FORCING... MODERATE AFTERNOON INSTABILITY (2000-2500 J/KG MAINLY ALONG/EAST OF HIGHWAY 1)... AND CONTINUED HIGH MOISTURE THROUGH THE COLUMN... HIGH PROBABILITIES OF SHOWERS/STORMS SHOULD EXTEND THROUGH SUNDAY. THE GFS/ECMWF SWING THE MIDLEVEL LOW OVER SE ONTARIO AND SRN QUEBEC/UPPER ST LAWRENCE... AMPLIFYING THE SOUTHERN PORTION OF THE MEAN TROUGH SUFFICIENTLY SO AS TO NUDGE THE FRONT TO ERN/SRN NC FOR MONDAY/TUESDAY. CONSIDERING THAT THE MODEL RUNS FROM A FEW DAYS AGO WERE PUSHING THIS FRONT TO OUR SOUTH AS EARLY AS SUNDAY AND HAVE NOW BACKED OFF ON THAT SCENARIO... AND CONSIDERING THAT TRUE COLD FRONT PASSAGE THROUGH NC WITHOUT A STRONG AMPLIFYING TROUGH IS A RARITY... I HAVE SOME RESERVATIONS ABOUT BRINGING IN A LOT OF STABLE OR MARKEDLY COOLER AIR INTO THE NRN/WRN CWA. WILL HOLD ONTO DAILY CHANCE POPS OVER THE ERN/SRN CWA... NEAR THE LIKELY POSITION OF THE FRONTAL ZONE... WITH SLIGHTLY LOWER POPS (BUT NOT ZERO) OVER THE NW BOTH MONDAY AND TUESDAY. THICKNESSES SHOULD DIP A BIT HEADING INTO EARLY NEXT WEEK... SO EXPECT HIGHS TO TREND FROM AROUND 90 SUNDAY INTO THE MID-UPPER 80S BY TUESDAY. LOWS IN THE UPPER 60S TO LOWER 70S... SLIPPING 2-3 DEGREES FROM SUNDAY TO TUESDAY. -GIH && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 740 AM WEDNESDAY... THE PATTERN OF A MOIST SOUTHERLY FLOW AND BETTER CHANCES OF SHOWERS OVER THE WESTERN PIEDMONT WILL CONTINUE THROUGH THE TAF PERIOD. CEILINGS HAVE BEEN HOVERING AROUND MVFR LEVELS IN THE TRIAD THIS MORNING...BUT SHOULD IMPROVE TO VFR BY MID-MORNING. MOST HI-RESOLUTION MODELS SHOW SHOWERS DEVELOPING TO THE SOUTH AND WEST OF KGSO/KINT BY 16Z...LIKELY MOVING INTO THE VICINITY OF THOSE TERMINALS THROUGHOUT THE AFTERNOON. WHILE A THUNDERSTORM IS CERTAINLY POSSIBLE...THE CHANCE APPEARS TO BE RELATIVELY LOW TODAY. MOST OF THE SHOWERS OR STORMS SHOULD THEN WEAKEN AND DISSIPATE AS THEY MOVE EAST INTO A MORE STABLE ENVIRONMENT OVER THE PIEDMONT AND COASTAL PLAIN. TONIGHT...STRATUS IS EXPECTED TO REDEVELOP LATE...PRIMARILY OVER THE WESTERN PIEDMONT...WITH A BETTER CHANCE OF LIMITED VSBYS AT EASTERN TERMINALS. OUTLOOK... MORNING STRATUS AND AFTERNOON SHOWERS/STORMS WILL BE POSSIBLE EACH DAY FOR THE REMAINDER OF THE WEEK...ALTHOUGH THE COVERAGE OF SHOWERS AND STORMS IS EXPECTED TO INCREASE FRIDAY AND SATURDAY AS A COLD FRONT MOVES INTO THE REGION FROM THE NORTHWEST. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...SMITH SHORT TERM..SMITH/HARTFIELD LONG TERM...HARTFIELD AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
705 AM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA MONDAY AND TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...06Z MODELS LOOK VERY SIMILAR TO THEIR 00Z COUNTERPARTS. THE ONE TREND I DID NOTICE IS AN INCREASE IN MID-LEVEL CLOUD COVER ACROSS MAINLY THE INTERIOR EASTERN CAROLINAS THROUGH MOST OF THE AFTERNOON. THIS HAS LED ME TO CHANGE SKY COVER FORECASTS TO "MOSTLY CLOUDY" ACROSS ALL OF THE INTERSTATE 95 CORRIDOR WITH A ONE-DEGREE TWEAK DOWNWARD IN FORECAST HIGHS AT FLO/LBT/UDG. NO SIGNIFICANT CHANGES HAVE BEEN MADE ALONG THE COAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... AFTER YESTERDAY`S FORECAST DEBACLE ALONG AND WEST OF THE INTERSTATE 95 CORRIDOR...I AM HOPING THIS IS A BETTER FORECAST FOR TODAY. SURFACE HIGH PRESSURE IS DEPARTING THE COASTAL MID-ATLANTIC REGION...BUT A RIDGE AXIS REMAINS ENTRENCHED ACROSS THE INTERIOR CAROLINAS. EASTERLY FLOW ACROSS THE ATLANTIC IS GRADUALLY WARMING AND MOISTENING AS THE SOURCE REGION FOR THE INCOMING STREAMLINES SHIFTS TO BERMUDA INSTEAD OF EASTERN CANADA. THE UPPER LEVEL PATTERN FEATURES A 500 MB RIDGE OVER EASTERN TEXAS WITH A WEAKENING LONGWAVE TROUGH OVER THE EASTERN U.S. 500 MB HEIGHTS SHOULD RISE BY ABOUT 20 METERS OVER THE CAROLINAS TODAY. ONE POTENTIAL PROBLEM DESPITE THE BUILDING RIDGE IS A WEAK SHORTWAVE TROUGH EMBEDDED IN THE WESTERLY UPPER LEVEL FLOW. THIS FEATURE IS COLLOCATED WITH A CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA EARLY THIS MORNING...AND IS DEPICTED BETTER IN THE GFS THAN THE NAM. IT SHOULD TRANSIT THE EASTERN CAROLINAS DURING THE LATE AFTERNOON HOURS...WEAKENING ALONG THE COAST THIS EVENING AS A COL (WEAK WIND REGION) DEVELOPS IN BETWEEN THE TEXAS AND BERMUDA RIDGES. AT THE RISK OF MAKING THE SAME MISTAKE I DID YESTERDAY...I SEE A VERY LOW RISK FOR SHOWERS TODAY GIVEN INSUFFICIENT MOISTURE AND WEAK LAPSE RATES WITHIN THE LOWER TROPOSPHERE. FORECAST SOUNDINGS FROM THE GFS...ECMWF AND RUC SHOW A CAPPED CONVECTIVE ENVIRONMENT. ONLY THE NAM DEVELOPS ANY SUBSTANTIAL SURFACE-BASED OR ELEVATED INSTABILITY TODAY (DUE TO SURFACE DEWPOINTS THAT LOOK TOO HIGH) BUT THAT MODEL ALSO SHOWS INSUFFICIENT FORCING FOR SHOWERS. THE 200-300 MB JET STREAM IS NOW WELL NORTH AND EAST OF THE CAROLINAS...TAKING ANY POTENTIAL UPPER DIVERGENT REGIONS OUT OF THE PICTURE LOCALLY. SCATTERED MID-LEVEL CLOUDS COULD BECOME A LITTLE MORE SUBSTANTIAL AT TIMES INLAND TODAY...BUT SHOULD NOT DO TOO MUCH TO HOLD TEMPERATURES DOWN. HIGHS ARE EXPECTED TO REACH 87-88 INLAND WITH MID 80S NEAR THE COAST. FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH LOWS 69-74...WARMEST AT THE COAST. MODELS ARE HINTING AT THE SOUTHEAST FLOW ALONG THE COAST POTENTIALLY YIELDING SOME MARINE SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A TREND OF INCREASING POPS TOWARD SUNRISE THURSDAY AT THE BEACHES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE SEABREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS UNCHANGED FOR THE MOST PART. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY. PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON HOURS...DIMINISHING TONIGHT. SOME LIGHT FOG IS POSSIBLE AFTER 08Z...MAINLY INLAND. EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...THE ONLY CHANGE TO THE FORECAST WAS TO BACK WIND DIRECTIONS BY 20-30 DEGREES FOR THE REMAINDER OF THE MORNING... STILL VEERING SOUTHEASTERLY THIS AFTERNOON. WIND SPEEDS AND SEA HEIGHTS STILL LOOK GOOD. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... HIGH PRESSURE OFF THE MID-ATLANTIC COAST SHOULD MOVE FARTHER OUT TO SEA TODAY...BUT A SURFACE RIDGE AXIS WILL REMAIN PARKED ACROSS INTERIOR NORTH CAROLINA. UNTIL THIS RIDGE AXIS BREAKS DOWN DURING THE DAY THURSDAY OUR WIND DIRECTIONS WILL NOT VEER SIGNIFICANTLY FROM EAST-SOUTHEAST. MODELS ARE IN EXCELLENT AGREEMENT WITH WIND SPEEDS...EXPECTED TO AVERAGE 10 KNOTS BOTH TODAY AND TONIGHT. SEAS CURRENTLY AROUND 2 FT SHOULD CHANGE VERY LITTLE THROUGH TONIGHT WITH VIRTUALLY NO SWELL ENERGY VISIBLE ON SPECTRAL WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY. SHOWER CHANCES WILL REMAIN VERY LOW THROUGH THIS EVENING...BUT MAY INCREASE A LITTLE AFTER MIDNIGHT TONIGHT...ESPECIALLY OFFSHORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS. THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN KNOTS.WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT SEAS OF 2-3 FEET. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...SHK LONG TERM...SHK AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
635 AM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA MONDAY AND TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...06Z MODELS LOOK VERY SIMILAR TO THEIR 00Z COUNTERPARTS. THE ONE TREND I DID NOTICE IS AN INCREASE IN MID-LEVEL CLOUD COVER ACROSS MAINLY THE INTERIOR EASTERN CAROLINAS THROUGH MOST OF THE AFTERNOON. THIS HAS LED ME TO CHANGE SKY COVER FORECASTS TO "MOSTLY CLOUDY" ACROSS ALL OF THE INTERSTATE 95 CORRIDOR WITH A ONE-DEGREE TWEAK DOWNWARD IN FORECAST HIGHS AT FLO/LBT/UDG. NO SIGNIFICANT CHANGES HAVE BEEN MADE ALONG THE COAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... AFTER YESTERDAY`S FORECAST DEBACLE ALONG AND WEST OF THE INTERSTATE 95 CORRIDOR...I AM HOPING THIS IS A BETTER FORECAST FOR TODAY. SURFACE HIGH PRESSURE IS DEPARTING THE COASTAL MID-ATLANTIC REGION...BUT A RIDGE AXIS REMAINS ENTRENCHED ACROSS THE INTERIOR CAROLINAS. EASTERLY FLOW ACROSS THE ATLANTIC IS GRADUALLY WARMING AND MOISTENING AS THE SOURCE REGION FOR THE INCOMING STREAMLINES SHIFTS TO BERMUDA INSTEAD OF EASTERN CANADA. THE UPPER LEVEL PATTERN FEATURES A 500 MB RIDGE OVER EASTERN TEXAS WITH A WEAKENING LONGWAVE TROUGH OVER THE EASTERN U.S. 500 MB HEIGHTS SHOULD RISE BY ABOUT 20 METERS OVER THE CAROLINAS TODAY. ONE POTENTIAL PROBLEM DESPITE THE BUILDING RIDGE IS A WEAK SHORTWAVE TROUGH EMBEDDED IN THE WESTERLY UPPER LEVEL FLOW. THIS FEATURE IS COLLOCATED WITH A CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA EARLY THIS MORNING...AND IS DEPICTED BETTER IN THE GFS THAN THE NAM. IT SHOULD TRANSIT THE EASTERN CAROLINAS DURING THE LATE AFTERNOON HOURS...WEAKENING ALONG THE COAST THIS EVENING AS A COL (WEAK WIND REGION) DEVELOPS IN BETWEEN THE TEXAS AND BERMUDA RIDGES. AT THE RISK OF MAKING THE SAME MISTAKE I DID YESTERDAY...I SEE A VERY LOW RISK FOR SHOWERS TODAY GIVEN INSUFFICIENT MOISTURE AND WEAK LAPSE RATES WITHIN THE LOWER TROPOSPHERE. FORECAST SOUNDINGS FROM THE GFS...ECMWF AND RUC SHOW A CAPPED CONVECTIVE ENVIRONMENT. ONLY THE NAM DEVELOPS ANY SUBSTANTIAL SURFACE-BASED OR ELEVATED INSTABILITY TODAY (DUE TO SURFACE DEWPOINTS THAT LOOK TOO HIGH) BUT THAT MODEL ALSO SHOWS INSUFFICIENT FORCING FOR SHOWERS. THE 200-300 MB JET STREAM IS NOW WELL NORTH AND EAST OF THE CAROLINAS...TAKING ANY POTENTIAL UPPER DIVERGENT REGIONS OUT OF THE PICTURE LOCALLY. SCATTERED MID-LEVEL CLOUDS COULD BECOME A LITTLE MORE SUBSTANTIAL AT TIMES INLAND TODAY...BUT SHOULD NOT DO TOO MUCH TO HOLD TEMPERATURES DOWN. HIGHS ARE EXPECTED TO REACH 87-88 INLAND WITH MID 80S NEAR THE COAST. FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH LOWS 69-74...WARMEST AT THE COAST. MODELS ARE HINTING AT THE SOUTHEAST FLOW ALONG THE COAST POTENTIALLY YIELDING SOME MARINE SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A TREND OF INCREASING POPS TOWARD SUNRISE THURSDAY AT THE BEACHES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE SEABREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS UNCHANGED FOR THE MOST PART. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...EXPECT VFR THROUGH THE PERIOD WITH THE EXCEPTION OF MVFR DUE TO FOG AT THE INLAND SITES LATE OVERNIGHT BEFORE DAYBREAK. LIGHT WINDS AND MAINLY MID AND HIGH CLOUDS WILL CONTINUE INTO THE OVERNIGHT HOURS. ANTICIPATE MVFR DUE TO FOG TO DEVELOP IN A FEW HOURS AT FLO AND LBT. MOISTURE POOLING AROUND 2000 FT AGL COULD ALSO DEVELOP SOME STRATUS AT THE INLAND AIRPORTS. AFTER DAYBREAK...VFR WILL PREVAIL WITH LIGHT SOUTH-SOUTHEAST WINDS BECOMING AOB 10 KTS ON WEDNESDAY...BECOMING LIGHT INTO THE EVENING HOURS. EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...THE ONLY CHANGE TO THE FORECAST WAS TO BACK WIND DIRECTIONS BY 20-30 DEGREES FOR THE REMAINDER OF THE MORNING... STILL VEERING SOUTHEASTERLY THIS AFTERNOON. WIND SPEEDS AND SEA HEIGHTS STILL LOOK GOOD. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... HIGH PRESSURE OFF THE MID-ATLANTIC COAST SHOULD MOVE FARTHER OUT TO SEA TODAY...BUT A SURFACE RIDGE AXIS WILL REMAIN PARKED ACROSS INTERIOR NORTH CAROLINA. UNTIL THIS RIDGE AXIS BREAKS DOWN DURING THE DAY THURSDAY OUR WIND DIRECTIONS WILL NOT VEER SIGNIFICANTLY FROM EAST-SOUTHEAST. MODELS ARE IN EXCELLENT AGREEMENT WITH WIND SPEEDS...EXPECTED TO AVERAGE 10 KNOTS BOTH TODAY AND TONIGHT. SEAS CURRENTLY AROUND 2 FT SHOULD CHANGE VERY LITTLE THROUGH TONIGHT WITH VIRTUALLY NO SWELL ENERGY VISIBLE ON SPECTRAL WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY. SHOWER CHANCES WILL REMAIN VERY LOW THROUGH THIS EVENING...BUT MAY INCREASE A LITTLE AFTER MIDNIGHT TONIGHT...ESPECIALLY OFFSHORE. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS. THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN KNOTS.WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT SEAS OF 2-3 FEET. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...SHK LONG TERM...SHK AVIATION...SGL
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
900 AM EDT WED AUG 7 2013 .SYNOPSIS... MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION. COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... MORNING UPDATE...MADE SOME VERY MINOR CHANGES TO THE AERIAL EXTENT OF THE SCATTERED SHOWER AND ISOLATED THUNDERSTORM COVERAGE THIS MORNING BASED ON THE LOCATION OF ACCAS AS WELL AS THE CONVECTION IN EASTERN KENTUCKY. ASIDE FROM THESE TWO FEATURES MUCH OF THE AFTERNOON STORMS WILL BE OF THE HEATING GENERATED AIR MASS VARIETY SO STUCK WITH THE TREND OF BROADENING CHANCE POPS AND LIKELIES SPREADING IN FROM THE SOUTH AND WEST. PREVIOUS DISCUSSION...DIFFICULT NEAR TERM FORECAST ON THIS GRAVEYARD SHIFT...IN THESE WANING DOG DAYS OF SUMMER. THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT WITH A FEW SHOWERS DEVELOPING ON RADAR. THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY. SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO 50 PERCENT RANGE THERE TODAY. PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT TERM PERIOD. WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM TEMPERATURES BELOW GFS MOS GUIDANCE. A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40 PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY TIME. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH SLOWER FRONT. CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR. WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST. HOWEVER...TRIMMED POPS FOR LATE IN THE PERIOD AS I THOUGHT THEY WERE TOO HIGH...BASED ON THE WPC DAYS 4-7 SFC PROGS. WPC INDICATES AN AREA OF LOW PRESSURE SHOULD BE LOCATED JUST TO OUR WEST WITH A FRONT EXTENDING EAST-WEST ACROSS OUR FORECAST AREA. THE LOW SHOULD MOVE SOUTHEAST ON SUNDAY...DRAGGING A COLD FRONT WITH IT. BY MONDAY MORNING...SFC LOW SHOULD BE LOCATED JUST OFF THE EAST COAST WITH THE FRONT TO OUR SOUTH AND EAST. THIS BOUNDARY IS EXPECTED TO MOVE LITTLE THROUGH THE REMAINDER OF OUR PERIOD. MODELS SUGGEST SEVERAL SHORTWAVES WILL PUSH EAST/SOUTHEAST WITH TIME. WITH FRONT TO OUR SOUTHEAST...EXPECT THESE FEATURES MAY BE SUFFICIENT FOR A FEW SHOWERS/STORMS ACROSS OUR SOUTH AND EAST MONDAY INTO WEDNESDAY. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... PATCHY CLOUDS AND ISOLATED SHOWER DID FORM 06Z TO 10Z...KEEPING VSBY MOSTLY AOA 5 MILES. THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING THE CONVECTION. IN THE 12Z SET OF TAFS WILL UP THE TIME AN HOUR OR TWO FOR THE COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASING IN THE TRI STATE AROUND HTS AND SOUTHERN WEST VIRGINIA INTO SOUTHWEST VIRGINIA DURING THE 15Z TO 18Z TIME FRAME...THEN MOVING EAST 18Z WEDNESDAY TO 00Z THURSDAY. COVERAGE OF CONVECTION PKB TO CKB DIFFICULT TO FIGURE BUT HAVE POPS MAXING OUT THERE BETWEEN 18Z TO 00Z. QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3 THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT. VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z THURSDAY AND REMAINING MOSTLY MVFR F BECAUSE OF CLOUDS COVER. VSBY AOB 3 MILES IN CONVECTION. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY. THE CUMULUS CEILINGS MAY SCATTER OUT IN PLACES LATE TODAY AND THIS EVENING...LEAVING CEILING AT HIGHER LAYERS THAN FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY M M M H H H M M M M M M HTS CONSISTENCY H H H H H M M M M M M M BKW CONSISTENCY M M M M H M M M M M M M EKN CONSISTENCY M M M M M H H H M M M M PKB CONSISTENCY M M M H M M M M M M M M CKB CONSISTENCY M M M H H H M M M M M M AFTER 12Z THURSDAY... IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY AT NIGHT AND INTO THE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB/JR SHORT TERM...MZ LONG TERM...JSH AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
851 AM EDT WED AUG 7 2013 .SYNOPSIS... MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION. COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... DIFFICULT NEAR TERM FORECAST ON THIS GRAVEYARD SHIFT...IN THESE WANING DOG DAYS OF SUMMER. THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT WITH A FEW SHOWERS DEVELOPING ON RADAR. THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY. SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO 50 PERCENT RANGE THERE TODAY. PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT TERM PERIOD. WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM TEMPERATURES BELOW GFS MOS GUIDANCE. A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40 PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY TIME. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH SLOWER FRONT. CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR. WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST. HOWEVER...TRIMMED POPS FOR LATE IN THE PERIOD AS I THOUGHT THEY WERE TOO HIGH...BASED ON THE WPC DAYS 4-7 SFC PROGS. WPC INDICATES AN AREA OF LOW PRESSURE SHOULD BE LOCATED JUST TO OUR WEST WITH A FRONT EXTENDING EAST-WEST ACROSS OUR FORECAST AREA. THE LOW SHOULD MOVE SOUTHEAST ON SUNDAY...DRAGGING A COLD FRONT WITH IT. BY MONDAY MORNING...SFC LOW SHOULD BE LOCATED JUST OFF THE EAST COAST WITH THE FRONT TO OUR SOUTH AND EAST. THIS BOUNDARY IS EXPECTED TO MOVE LITTLE THROUGH THE REMAINDER OF OUR PERIOD. MODELS SUGGEST SEVERAL SHORTWAVES WILL PUSH EAST/SOUTHEAST WITH TIME. WITH FRONT TO OUR SOUTHEAST...EXPECT THESE FEATURES MAY BE SUFFICIENT FOR A FEW SHOWERS/STORMS ACROSS OUR SOUTH AND EAST MONDAY INTO WEDNESDAY. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... PATCHY CLOUDS AND ISOLATED SHOWER DID FORM 06Z TO 10Z...KEEPING VSBY MOSTLY AOA 5 MILES. THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING THE CONVECTION. IN THE 12Z SET OF TAFS WILL UP THE TIME AN HOUR OR TWO FOR THE COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASING IN THE TRI STATE AROUND HTS AND SOUTHERN WEST VIRGINIA INTO SOUTHWEST VIRGINIA DURING THE 15Z TO 18Z TIME FRAME...THEN MOVING EAST 18Z WEDNESDAY TO 00Z THURSDAY. COVERAGE OF CONVECTION PKB TO CKB DIFFICULT TO FIGURE BUT HAVE POPS MAXING OUT THERE BETWEEN 18Z TO 00Z. QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3 THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT. VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z THURSDAY AND REMAINING MOSTLY MVFR F BECAUSE OF CLOUDS COVER. VSBY AOB 3 MILES IN CONVECTION. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY. THE CUMULUS CEILINGS MAY SCATTER OUT IN PLACES LATE TODAY AND THIS EVENING...LEAVING CEILING AT HIGHER LAYERS THAN FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY M M M H H H M M M M M M HTS CONSISTENCY H H H H H M M M M M M M BKW CONSISTENCY M M M M H M M M M M M M EKN CONSISTENCY M M M M M H H H M M M M PKB CONSISTENCY M M M H M M M M M M M M CKB CONSISTENCY M M M H H H M M M M M M AFTER 12Z THURSDAY... IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY AT NIGHT AND INTO THE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB SHORT TERM...MZ LONG TERM...JSH AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
621 AM EDT WED AUG 7 2013 .SYNOPSIS... MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION. COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... DIFFICULT NEAR TERM FORECAST ON THIS GRAVEYARD SHIFT...IN THESE WANING DOG DAYS OF SUMMER. THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT WITH A FEW SHOWERS DEVELOPING ON RADAR. THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY. SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO 50 PERCENT RANGE THERE TODAY. PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT TERM PERIOD. WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM TEMPERATURES BELOW GFS MOS GUIDANCE. A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40 PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY TIME. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH SLOWER FRONT. CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR. WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST. HOWEVER...HAVE MADE SOME CHANGES TO REFLECT DIFFERENCES IN LATEST MODEL GUIDANCE. WPC INDICATES A COLD FRONT SHOULD BE LOCATED JUST TO OUR NORTHWEST EARLY IN THE PERIOD...SLOWLY SINKING SOUTH. SEVERAL MID-LEVEL SHORTWAVES AND A WEAK AREA OF LOW PRESSURE WILL THEN PUSH EAST MONDAY INTO TUESDAY. LATEST GFS IS SLOWER WITH THE SOUTHEAST PROGRESS OF THE COLD FRONT. WITH THIS IN MIND...HAVE HELD ONTO LOW POPS A LITTLE LONGER FOR SATURDAY NIGHT INTO SUNDAY. LOWERED HPC TEMP NUMBERS A FEW DEGREES AS THEY APPEAR TOO WARM FOR THE EXPECTED CONDITIONS. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... PATCHY CLOUDS AND ISOLATED SHOWER DID FORM 06Z TO 10Z...KEEPING VSBY MOSTLY AOA 5 MILES. THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING THE CONVECTION. IN THE 12Z SET OF TAFS WILL UP THE TIME AN HOUR OR TWO FOR THE COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASING IN THE TRI STATE AROUND HTS AND SOUTHERN WEST VIRGINIA INTO SOUTHWEST VIRGINIA DURING THE 15Z TO 18Z TIME FRAME...THEN MOVING EAST 18Z WEDNESDAY TO 00Z THURSDAY. COVERAGE OF CONVECTION PKB TO CKB DIFFICULT TO FIGURE BUT HAVE POPS MAXING OUT THERE BETWEEN 18Z TO 00Z. QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3 THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT. VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z THURSDAY AND REMAINING MOSTLY MVFR F BECAUSE OF CLOUDS COVER. VSBY AOB 3 MILES IN CONVECTION. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY. THE CUMULUS CEILINGS MAY SCATTER OUT IN PLACES LATE TODAY AND THIS EVENING...LEAVING CEILING AT HIGHER LAYERS THAN FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY M M M H H H M M M M M M HTS CONSISTENCY H H H H H M M M M M M M BKW CONSISTENCY M M M M H M M M M M M M EKN CONSISTENCY M M M M M H H H M M M M PKB CONSISTENCY M M M H M M M M M M M M CKB CONSISTENCY M M M H H H M M M M M M AFTER 12Z THURSDAY... IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY AT NIGHT AND INTO THE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ SHORT TERM...MZ LONG TERM...JSH AVIATION...KTB
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1009 AM CDT WED AUG 7 2013 .DISCUSSION... THE MCS SKIRTING THE NORTHERN FRINGES OF THE MIDSOUTH HAS BEEN WEAKENING OVER THE LAST COUPLE OF HOURS. THIS COMPLEX WILL SHIFT ESE OVER THE NEXT FEW HOURS AND CONTINUE TO BREAK APART. SOME GRAVITY WAVES THAT...EMANATED FROM THE MCS...ARE VISIBLE ON THE KNQA 88D IMAGERY ACROSS CENTRAL CRITTENDEN AND NORTHERN SHELBY COUNTIES. A MORE SIGNIFICANT BOUNDARY STRETCHES FROM EASTERN LAUDERDALE COUNTY INTO NORTH CROSS COUNTY. THIS MARKS THE LEADING EDGE OF THE COLD POOL. THIS BOUNDARY...COMBINED WITH CLOUD COVER...SHOULD LIMIT THE POTENTIAL HIGH TEMPS TODAY ACROSS MUCH OF THE MIDSOUTH. CURRENT FORECAST IS FAIRLY CONSERVATIVE WITH TEMPS AND THEY LOOK GOOD ATTM. HRRR DOES A GOOD JOB DEPICTING THIS SOUTHWARD MOVING OUTFLOW BOUNDARY AND SHOWS SHOWERS AND THUNDERSTORMS DEVELOPING ALONG IT AS IN MOVES THROUGH AN INCREASINGLY UNSTABLE AIRMASS ACROSS NORTH MISSISSIPPI EARLY THIS AFTERNOON. INCREASED POPS ALONG THE NORTHERN TIER FOR THE REMAINDER OF THE MORNING DUE TO ONGOING MCS. DECREASED POPS ALONG THE NORTHERN TIER THIS AFTERNOON IN ANTICIPATION THAT THE MCS MOVES OFF TO THE ESE. ADDED POPS TO THE SOUTHWEST PART OF THE CWA...DELTA REGION...DUE TO THE OUTFLOW BOUNDARY MOVING THROUGH. UPDATE OUT. SJM && PREV DISCUSSION... /ISSUED 236 AM CDT WED AUG 7 2013/ ANOTHER DAY AND ANOTHER MCS TO AFFECT THE MIDSOUTH TODAY. LATEST RADAR IMAGES ARE LOOKING VERY REMINISCENT FROM LAST NIGHT. A LARGE MCS IS CURRENTLY LOCATED OVER SOUTHEAST KANSAS AND NORTHEAST OKLAHOMA AT THIS TIME. THE ONLY DIFFERENCE MAY BE IS THAT THE MCS IS A LITTLE SLOWER SINCE BY THIS TIME LAST NIGHT THE MCS HAD CROSSED INTO SOUTHWEST MISSOURI AND THE SOUTHERN EXTENT IS FURTHER SOUTH THAN LAST NIGHTS. ON ITS CURRENT TRACK EXPECT THE REMNANTS TO MOVE INTO NORTHEAST ARKANSAS BY 8 AM THIS MORNING. MEANWHILE...ADDITIONAL CONVECTION HAS FIRED UP ACROSS SOUTHEAST MISSOURI. THIS IS PRETTY SIMILAR TO WHAT OCCURRED LAST NIGHT. THE CONVECTION IS ON THE NOSE OF THE LOW LEVEL JET AND AHEAD OF AN APPROACHING WARM FRONT THAT IS CURRENTLY LOCATED FROM NEAR JONESBORO TO CORINTH. THE CONVECTION IS EXPECTED TO EXPAND AND INCREASE IN COVERAGE OVER THE NEXT COUPLE OF HOURS. ALREADY SEEING THE FIRST SHOWERS POP UP OBION AND LAKE COUNTIES. THE ATMOSPHERE IS VERY MOIST WITH PW/S OBSERVED AT 2.11 INCHES OFF THE 00Z BNA SOUNDING. ISOLATED LOCATIONS ACROSS THE AREA SUCH AS WEAKLEY COUNTY HAVE ALREADY RECEIVED A LARGE AMOUNT OF RAINFALL. FLASH FLOOD GUIDANCE FOR ONE HOUR IS AT 1.8 FOR WEAKLEY COUNTY SO FLASH FLOODING WILL BE A THREAT AGAIN TODAY FROM ANY THUNDERSTORMS THAT DEVELOP OVER THE AREA. EXPECT BY MIDDAY...CONVECTION WILL BE THE GREATEST ACROSS WEST TENNESSEE NEAR THE TENNESSEE RIVER. CLOUDS AND CONVECTION WILL KEEP TEMPERATURES DOWN ACROSS AT LEAST THE NORTHEAST HALF OF THE CWA. EXPECT HIGHS IN THE LOWER TO MID 80S. MEANWHILE...ACROSS THE SOUTHWEST HALF OF THE CWA TEMPERATURES SHOULD GET UP INTO THE LOWER TO MID 90S UNLESS ABUNDANT CIRRUS FROM MCS KEEPS CONDITIONS COOLER. DEPENDING ON DEWPOINTS...PHILLIPS COUNTY ARKANSAS AND PORTIONS OF NORTHWEST MISSISSIPPI MAY NEED TO BE MONITORED FOR A HEAT ADVISORY. NOT CONFIDENT AT THIS POINT TO ISSUE ONE DUE TO THE AMOUNT OF CLOUD COVER HEADING TOWARD THE MIDSOUTH AT THIS TIME. MODELS SUGGEST THE FRONTAL BOUNDARY WILL BE LOCATED NEAR THE MO/AR BORDER THIS EVENING. EXPECT THE BOUNDARY TO BE THE MAIN SOURCE OF CONVECTION. CAN/T RULE OUT ANOTHER MCS DEVELOPING AS WELL THUS WILL KEEP HIGHEST POPS ACROSS THE NORTHERN AREAS. CONFIDENCE IN FORECAST DROPS OFF AFTER TONIGHT. MODELS SUGGEST FRONT MAY LIFT NORTHWARD INTO MISSOURI THURSDAY NIGHT INTO FRIDAY THUS ANY MCS WOULD STAY NORTH OF THE CWA THURSDAY NIGHT INTO FRIDAY MORNING. WILL THIS HAPPEN...WHO KNOWS. HOWEVER...AT LEAST DIURNAL CONVECTION SHOULD STILL BE POSSIBLE ON FRIDAY. THE COLD FRONT SHOULD SAG SOUTH INTO THE CWA OVER THE WEEKEND AND BRING DECENT CHANCES FOR SHOWERS AND THUNDERSTORMS. HAVE BUMPED UP POPS FOR SATURDAY AS A RESULT. HOW FAR SOUTH THE FRONT GOES REMAINS A QUESTION THAT THE 00Z GFS AND 00Z ECMWF DIFFER ON REGARDING THEIR SOLUTIONS. AS A RESULT...HAVE LEFT FORECAST AS IS FOR MONDAY AND TUESDAY. KRM && .AVIATION... ONCE AGAIN BASED THE TAFS ON PERSISTENCE AND RADAR TRENDS MORE THAN ANYTHING ELSE. CONVECTION UPSTREAM ACROSS MISSOURI WILL CONTINUE TO SINK SOUTH AND EAST. FEEL LIKELY MOST OF THE STORMS WILL STAY NORTH OF MEM...AND MOST LIKELY JBR...MOST CERTAINLY TUP. MKL WILL LIKELY SEE STORMS ARRIVE AROUND 14Z...WITH PREVAILING STORMS POSSIBLE SOMETIME BETWEEN 16AND 17Z. WILL TEMPO 3SM TSRA AT MKL...FOR PLANNING PURPOSES...BUT THE EXACT TIME MAY NEED TO BE ADJUSTED...ESPECIALLY IF ADDITIONAL STORMS DEVELOP AHEAD OF THE ONGOING CONVECTION. ONLY INCLUDED VCTS AT JBR AND MEM FOR NOW...STARTING AT 16Z...AND VCSH BY 20Z. ONCE AGAIN...ADDITIONAL DEVELOPMENT MAY REQUIRE AMENDMENTS. LIGHT SOUTHERLY WINDS WILL PREVAIL AT ALL SITES...BUT COULD BECOME VARIABLE AND GUSTY IN ASSOCIATION WITH STORMS. JBR MAY SEE A EASTERLY SHIFT IN WINDS OVERNIGHT. FOG MAY DEVELOP AT MKL AFTER 06Z TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... MEM 93 77 93 78 / 20 30 20 10 MKL 83 73 88 74 / 60 50 50 20 JBR 88 75 90 75 / 50 30 30 20 TUP 92 74 92 74 / 40 20 40 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
913 AM CDT WED AUG 7 2013 .UPDATE... Isolated convection is ongoing over West TX this morning but this activity is expected to dissipate over the next 1-2 hours. Scattered altocumulus castellanus (ACCAS) have developed over portions of West Central TX...indicating some mid level instability. We`ll see relatively quiet weather conditions through early afternoon with a surface based cu field developing after noon. With temperatures warming well above 100 degrees, we should not have any trouble tapping into this instability. Low-level forcing will be tied to a surface trough although convergence will not be all that strong. On the water vapor loop, the primary feature of interest is the compact upper cyclone found to our south near the Big Bend. This low is favorably located to enhance upper-level divergence across West Central TX today. This could yield slightly better convective coverage than I`m currently anticipating. I did change the thunderstorms in the forecast to areal qualifiers and made minor changes in the dewpoint, wind and sky grids. The public and fire weather forecast products have been updated. Johnson && .PREV DISCUSSION... /ISSUED 647 AM CDT WED AUG 7 2013/ DISCUSSION... See 12Z aviation discussion below. AVIATION... VFR conditions will prevail across the terminals the next 24 hours. Isolated to widely scattered thunderstorms may develop late this afternoon and early evening across western portions of the Big Country, Concho Valley and northern Edwards Plateau. However, limited coverage will preclude mentioning in the TAFS at this time. PREV DISCUSSION... /ISSUED 448 AM CDT WED AUG 7 2013/ SHORT TERM... The main concern today will be convective chances late this afternoon and evening and heat advisory conditions across the Big Country. The upper level high will be positioned over eastern Texas today with a surface trough situated over our western counties by late afternoon. A cold front currently over southern Kansas is expected to drop south into northwest Texas by afternoon and become stationary through the evening hours. Compressional warming ahead of the front along with 850 millibar temperatures between 28 and 30 degrees Celsius will result in very hot temperatures again today. The hottest temperatures will occur across the northeastern half of the Big Country where compressional warming effects will be greatest. Afternoon highs across this area will top out between 103 and 106 degrees with corresponding heat indices between 104 and 107 degrees. Elsewhere, expected highs between 100 and 104 degrees with slightly lower heat indices. Included Jones County to the latest heat advisory which also covers Haskell, Throckmorton and Shackelford counties until 8 pm this evening. The aforementioned surface trough will be a focus for convective development by late afternoon across western counties as the cap weakens with intense heating. The NAM seems to have a better handle on this scenario as does the HRRR with both showing development along the trough axis by late afternoon. Went ahead and added slight pops generally west of a Throckmorton, Eden to Sonora line through early evening. While widespread severe weather is not expected, inverted V profiles with large dewpoint depressions will be favorable for a few microbursts with the stronger cells. Storms will be diurnally driven and should dissipate by mid to late evening with loss of heating. Low temperatures tonight will generally be in the mid and upper 70s. 24 LONG TERM... Above normal temperatures will continue for all of West Central Texas through much of the extended forecast, although showers and thunderstorms may provide brief relief from the heat. Another hot day is forecast, although 850mb temperatures are slightly cooler than what we are expecting this afternoon. Highs should range from 99 to 102 over the southern counties to 101 to 104 across much of the Big Country. Isolated to scattered showers and thunderstorms are expected to develop along a surface trough across our western counties by late afternoon. I included a slight chance of showers and thunderstorms across mainly the western half of the area...with a chance across the extreme western Concho Valley and Big Country. In the meantime...a weak cold front will approach the northern Big Country during the late evening or early morning hours. Scattered showers and thunderstorms will be possible with the boundary...and I have kept a slight chance POPs going through the overnight hours for much of the Big Country. I trended my dewpoint temperatures closer to the more moist NAM through Friday. Model differences arise in the placement of a cold front across the region on Friday and Saturday. The NAM is the fastest with the boundary, stalling it across the Concho Valley during the early morning hours Friday, while the GFS and ECMWF are about 6 to 10 hours slower. Given the expected boundary across area and decent moisture to work with...I believe showers and thunderstorms will develop across parts of the Big Country, Heartland, and Concho Valley during the late afternoon/evening hours. Timing of the front will make a difference on both high temperatures and placement of best POPS, and for now I have kept a slight chance across generally the northern half of the region, and I tweaked highs down slightly. Although I cannot rule out an isolated shower or thunderstorms Saturday as the diffuse boundary remains in the area, confidence is not high enough to include in the forecast at this time. An inverted trough/low will move across South Texas Sunday into Monday, then into northern Mexico. Although the best dynamics associated with this feature will remain south of area area, it should pull in better gulf moisture Sunday and Monday. I cannot rule out diurnally driven isolated showers and thunderstorms during the afternoon hours, across mainly the southeast counties, but for now I have kept the forecast dry. High temperatures should be slightly above seasonal normals, generally in the mid and upper 90s, with lows in the 70s. Daniels && .PRELIMINARY POINT TEMPS/POPS... ABILENE 103 78 100 77 97 / 20 20 20 20 20 SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20 JUNCTION 103 76 101 73 100 / 10 10 5 5 10 && .SJT WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON. && $$ 25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
647 AM CDT WED AUG 7 2013 .DISCUSSION... See 12Z aviation discussion below. && .AVIATION... VFR conditions will prevail across the terminals the next 24 hours. Isolated to widely scattered thunderstorms may develop late this afternoon and early evening across western portions of the Big Country, Concho Valley and northern Edwards Plateau. However, limited coverage will preclude mentioning in the TAFS at this time. && .PREV DISCUSSION... /ISSUED 448 AM CDT WED AUG 7 2013/ .SHORT TERM... The main concern today will be convective chances late this afternoon and evening and heat advisory conditions across the Big Country. The upper level high will be positioned over eastern Texas today with a surface trough situated over our western counties by late afternoon. A cold front currently over southern Kansas is expected to drop south into northwest Texas by afternoon and become stationary through the evening hours. Compressional warming ahead of the front along with 850 millibar temperatures between 28 and 30 degrees Celsius will result in very hot temperatures again today. The hottest temperatures will occur across the northeastern half of the Big Country where compressional warming effects will be greatest. Afternoon highs across this area will top out between 103 and 106 degrees with corresponding heat indices between 104 and 107 degrees. Elsewhere, expected highs between 100 and 104 degrees with slightly lower heat indices. Included Jones County to the latest heat advisory which also covers Haskell, Throckmorton and Shackelford counties until 8 pm this evening. The aforementioned surface trough will be a focus for convective development by late afternoon across western counties as the cap weakens with intense heating. The NAM seems to have a better handle on this scenario as does the HRRR with both showing development along the trough axis by late afternoon. Went ahead and added slight pops generally west of a Throckmorton, Eden to Sonora line through early evening. While widespread severe weather is not expected, inverted V profiles with large dewpoint depressions will be favorable for a few microbursts with the stronger cells. Storms will be diurnally driven and should dissipate by mid to late evening with loss of heating. Low temperatures tonight will generally be in the mid and upper 70s. 24 .LONG TERM... Above normal temperatures will continue for all of West Central Texas through much of the extended forecast, although showers and thunderstorms may provide brief relief from the heat. Another hot day is forecast, although 850mb temperatures are slightly cooler than what we are expecting this afternoon. Highs should range from 99 to 102 over the southern counties to 101 to 104 across much of the Big Country. Isolated to scattered showers and thunderstorms are expected to develop along a surface trough across our western counties by late afternoon. I included a slight chance of showers and thunderstorms across mainly the western half of the area...with a chance across the extreme western Concho Valley and Big Country. In the meantime...a weak cold front will approach the northern Big Country during the late evening or early morning hours. Scattered showers and thunderstorms will be possible with the boundary...and I have kept a slight chance POPs going through the overnight hours for much of the Big Country. I trended my dewpoint temperatures closer to the more moist NAM through Friday. Model differences arise in the placement of a cold front across the region on Friday and Saturday. The NAM is the fastest with the boundary, stalling it across the Concho Valley during the early morning hours Friday, while the GFS and ECMWF are about 6 to 10 hours slower. Given the expected boundary across area and decent moisture to work with...I believe showers and thunderstorms will develop across parts of the Big Country, Heartland, and Concho Valley during the late afternoon/evening hours. Timing of the front will make a difference on both high temperatures and placement of best POPS, and for now I have kept a slight chance across generally the northern half of the region, and I tweaked highs down slightly. Although I cannot rule out an isolated shower or thunderstorms Saturday as the diffuse boundary remains in the area, confidence is not high enough to include in the forecast at this time. An inverted trough/low will move across South Texas Sunday into Monday, then into northern Mexico. Although the best dynamics associated with this feature will remain south of area area, it should pull in better gulf moisture Sunday and Monday. I cannot rule out diurnally driven isolated showers and thunderstorms during the afternoon hours, across mainly the southeast counties, but for now I have kept the forecast dry. High temperatures should be slightly above seasonal normals, generally in the mid and upper 90s, with lows in the 70s. Daniels && .PRELIMINARY POINT TEMPS/POPS... ABILENE 103 78 100 77 97 / 20 20 20 20 20 SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20 JUNCTION 103 76 101 73 100 / 10 10 5 5 10 && .SJT WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON. && $$ 24
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
956 AM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 950 AM EDT WEDNESDAY... THIS MORNING 8AM/12Z RNK SOUNDING SHOWED THAT A WEST FLOW CONTINUES ABOVE LOW LEVEL SOUTHERLY FLOW AND PWATS HAVE CLIMB TO 1.31 INCHES. HRRR AND RNKWRF-ARW INDICATED THAT BEST COVERAGE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL BE ACROSS THE WEST MOUNTAINS. CONTINUED THE MENTION OF HEAVY RAIN WITH AFTERNOON THUNDERSTORMS BECAUSE SOME OF THE THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. MADE SOME ADJUSTMENTS IN POPS AND WEATHER. INCREASED POPS ACROSS SOUTHWEST PORTIONS OF FORECAST AREA LATE MORNING INTO THIS AFTERNOON. ADJUSTED TEMPERATURES AND DEW POINTS ACCORDING TO LATEST OBS AND TRENDS. MORE CHANGES LATER THIS MORNING. AS OF 710 AM EDT WEDNESDAY... JUST A SHOWER OR TWO OUT THERE THIS MORNING ACROSS THE MOUNTAINS INTO THE ROANOKE VALLEY. ALSO DENSE FOG HAS BECOME AN ISSUE ACROSS THE BLUE RIDGE ALONG THE I-77 CORRIDOR AND SHOULD BURN OFF BY 14Z. LATEST MODELS ARE ADVERTISING SOME DIFFERENCES THIS MORNING. THE 06Z NAM/GFS 00Z ECMWF ARE SHOWING CONVECTION ACROSS E TN/NRN GA BUT OVERDOING THE COVERAGE. THE ECWMF HOWEVER IS DOING A BETTER JOB HANDLING THE MCS ACROSS MO INTO WRN KY. FOR THIS MORNING WILL KEEP CHANCE POPS INTO THE WEST PER CONVECTION POPPING ACROSS ERN KY ATTM...WITH LESS THREAT IN THE PIEDMONT. STILL LOOKS LIKE BEST CONVERGENCE ACROSS THE NC MTNS INTO FAR SRN WV THIS AFTERNOON...SO NO CHANGES TO POPS THERE WITH HIGH CHANCE TO LOW LIKELY. PREVIOUS VALID DISCUSSION... GIVEN HIGH PWATS ADDED HEAVY RAIN THREAT WITH THE THUNDERSTORMS. CANNOT RULE OUT ISOLATED FLASH FLOODING OR SVR SO WILL MENTION THAT IN THE HWO. LIKE TUESDAY...SKY COVER WILL BE VARIABLE BUT THINK MORE CLOUDS THAN SUN EXPECTED AND KEPT TEMPS CLOSE TO A MODEL/MOS BLEND FOR HIGHS WITH MID TO UPPER 70S WEST TO LOWER TO MID 80S EAST. TONIGHT...THERE IS A POTENTIAL FOR WHAT IS GOING ON IN KS/MO THIS MORNING TO GET CAUGHT UP IN THE WESTERLIES AS FLOW FLATTENS...MOVING TOWARD OUR MOUNTAINS OVERNIGHT. HOWEVER...MODELS ARE FAVORING KEEPING THE AXIS OF BEST LIFT...LOW LVL FORCING ACROSS THE OHIO/TN VALLEYS AND MAY SEE SOME STORMS MOVE INTO THE WESTERN CWA LATE. SO FOR NOW WILL KEEP HIGH CHANCE IN THE FAR WEST TONIGHT WITH DIMINISHING POPS IN THE EAST. WITH CONTINUED MORE CLOUDS AND HIGH MOIST CONTENT LOW TEMPS WILL BE IN THE 60S. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 400 AM EDT WEDNESDAY... WILL START THURSDAY OFF WITH ONLY ISOLATED SHOWERS THAT WILL BECOME WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS DURING THE AFTERNOON AND EVENING AS WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL WIND FLOW. WILL AGAIN SEE A THREAT OF LOCALLY HEAVY RAIN AS WEAKER UPPER LEVEL WINDS ASSOCIATED WITH THE BUILDING RIDGE TO OUR SOUTH RESULT IN SLOWER STORM MOVEMENT... WHILE DEEP ATMOSPHERIC MOISTURE POOLS AHEAD OF A COLD FRONT SITUATED NEAR THE OHIO RIVER. SHOWERS AND THUNDERSTORMS WILL BE MORE WIDESPREAD ON FRIDAY AS A SHORTWAVE ROTATING AROUND AN UPPER LOW NORTH OF THE GREAT LAKES WILL BEGIN TO NUDGE THE COLD FRONT FURTHER SOUTH. STRONG MOISTURE ADVECTION SOUTH OF THE FRONT WILL PUSH PRECIPITABLE WATER VALUES TO 2 INCHES OR MORE FOR MOST OF OUR AREA...AND AFTERNOON HEATING WILL PUSH CAPES INTO THE 1000 TO 1500 J/KG RANGE. WIND SPEEDS ALOFT WILL BE A LITTLE STRONGER...BUT BELIEVE THAT STORMS WHICH DEVELOP WITH AFTERNOON HEATING WILL BECOME VERY EFFICIENT RAINFALL PRODUCERS... ENHANCING THE FLASH FLOOD THREAT FOR OUR AREA. WOULD ALSO NOT BE SURPRISED TO SEE A FEW STORMS BECOME SEVERE...ESPECIALLY ACROSS THE PIEDMONTS...CAPABLE OF PRODUCING DAMAGING WINDS. MODELS ARE IN GENERAL AGREEMENT IN THEIR LATEST RUNS THAT THE SHORTWAVE TROUGH MOVING EAST ACROSS CANADA WILL ADVANCE THE COLD FRONT INTO NORTHERN VIRGINIA AND CENTRAL WEST VIRGINIA BY SATURDAY AFTERNOON. WILL GO WITH THE MODEL CONSENSUS ON FRONTAL PLACEMENT... KEEPING IN MIND THAT DISTURBANCES IN THE ZONAL FLOW ALOFT MAY CAUSE THE FRONT TO WAVER NORTH AND SOUTH AT TIMES. THAT STATED...TRULY DRIER AIR IS EXPECTED TO REMAIN WELL TO THE NORTH THROUGH SATURDAY NIGHT...AND WILL STILL EXPECT SCATTERED SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 400 AM EDT WEDNESDAY... LOOKING AT BETTER AGREEMENT IN THE LONG TERM MODELS FOR EARLY NEXT WEEK...WITH BOTH THE GFS AND ECMWF SOLUTIONS PUSHING THE COLD FRONT INTO THE CAROLINAS BY MONDAY MORNING. THE SOUTHWARD PUSH OF THE FRONT WILL MEAN ONLY SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS MONDAY AND TUESDAY...MAINLY SOUTH OF THE INTERSTATE 81 CORRIDOR. WILL BE KEEPING AN EYE ON ANOTHER WAVE ALOFT DROPPING OUT OF CANADA AND LIFTING MOISTURE BACK NORTH BY MIDWEEK...WHICH MAY SIGNAL A RETURN OF MORE WIDESPREAD CONVECTION. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 730 AM EDT WEDNESDAY... FOG AND MVFR CIGS WILL GIVE WAY TO VFR BY 15Z. SHOWERS AND STORMS ENTER THE WESTERN CWA AFTER 16Z WITH ACTIVITY MORE SCATTERED EAST OF ROANOKE THIS AFTERNOON. WILL STILL KEEP VCTS IN ALL TAFS AND HAVE -SHRA IN THE PREDOMINANT WX. FOR NOW KEEPING VSBYS AOA 6SM AND WILL HAVE TO AMEND IF STORMS HEAD TOWARD A TERMINAL. CONFIDENCE IS HIGH THAT LWB/BLF WILL SEE RAIN. AS IS THE CASE THIS TIME OF YEAR...STORMS IN A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS DOWN AND LOWER CIGS/VSBYS. TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR VSBYS ARE POSSIBLE. FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE TIME...IT SHOULD BE VFR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...KK/WP SHORT TERM...NF LONG TERM...JH AVIATION...WP
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
351 PM MDT WED AUG 7 2013 .SHORT TERM...A COMPLEX PICTURE TODAY WITH SEVERAL UPPER LEVEL SHORTWAVES EMBEDDED WITHIN AN OVERALL WEAK TROUGH CENTERED BACK TOWARDS THE FOUR CORNERS REGION. SATELLITE WATER VAPOR LOOP CAPTURES THINGS BEST. ONE FEATURE WENT BY THIS MORNING INTO EARLY AFTERNOON WITH SOME THUNDERSTORM ACTIVITY EAST OF DENVER THAT HAS SINCE MOVED OFF AND WEAKENED. THE PLATTEVILLE PROFILER SHOWS THIS I BELIEVE CENTERED AROUND 600 MB. WIDESPREAD CLOUDINESS BUT NOT MUCH RAIN FOR MOST OF THE REST OF THE FORECAST AREA WHICH HAS KEPT TEMPERATURES ON THE COOL SIDE AND THUNDER LIMITED SO FAR. MORE SUN AND WARMER CONDITIONS HAVE BEEN PRESENT SOUTH OF THE PALMER DIVIDE AND A SECOND WAVE SEEN IN THE WATER VAPOR IMAGERY AND CAPTURED BY THE RAP ANALYSES IS MOVING INTO THIS AREA WITH THUNDERSTORMS RAPIDLY DEVELOPING. THESE SHOULD MOVE INTO THE PALMER DIVIDE REGION OVER THE NEXT SEVERAL HOURS SO WILL CONTINUE THE FLASH FLOOD WATCH. ALTHOUGH SURFACE WARMING HAS BEEN LIMITED ACROSS THE PALMER DIVIDE COMPARED TO SOUTHEAST COLORADO DEW POINTS ARE QUITE HIGH WITH 61 NOW AT LIMON. ANOTHER WAVE IS FOUND FARTHER SOUTH MOVING NORTH INTO SOUTHWEST COLORADO AND THIS FEATURE IF IT HOLDS TOGETHER COULD HELP SUPPORT MORE ACTIVITY LATER TONIGHT AGAIN TO THE EAST OF DENVER. SEE THIS SECOND WAVE IN THE LATEST HRRR FORECAST RUN FROM 19Z BUT HRRR KEEPS IT RATHER FAR TO THE SOUTH AS IT APPROACHES NEAR 06Z. MAYBE TOO FAR SOUTH AS IT ALSO SEEMS TO BE WITH THE CURRENT WAVE OF STORMS MOVING EAST OF PUB AND COS. MEANWHILE AN UPPER LEVEL CIRCULATION REMAINS BEHIND NEAR THE FOUR CORNERS AND WHAT IS LEFT OF THIS COULD BE A FACTOR TOMORROW OR SHIFT MORE TO THE EAST. THE MAIN PRECIPITATION LOOKS LIKE IT WILL CONTINUE TO STAY EAST AND SOUTH OF DENVER. THERE IS ANOTHER AREA OF MORE SCATTERED THUNDERSTORMS OVER THE FOOTHILLS OVER LARIMER COUNTY AND SOME OF THESE COULD MOVE ONTO THE ADJACENT FRONT RANGE. MEANWHILE THERE CONTINUES TO BE A WIDE RANGE OF MODEL SOLUTIONS EVEN FOR THE PRECIPITATION IN THE NEXT 6 TO 12 HOURS. THE 12Z GFS HAD THE MOST ORGANIZED WIDESPREAD HEAVY RAIN AREA AS IT ORGANIZED ONE OF THE ABOVE NOTED FEATURES INTO A COMPACT CIRCULATION AT 700 MB. OTHER MODELS KEEP MOST OF THE PRECIP MUCH FARTHER TO THE SOUTH. LATEST HRRR HAS A WAVE OF PRECIP NEXT FEW HOURS THEN STAYS FARTHER SOUTH. SOMETHING IN BETWEEN THE EXTREMES LOOKS MOST LIKELY AND KEPT HIGHEST POPS OVER THE PALMER DIVIDE AND FAR EASTERN ZONES LINGERING INTO THURSDAY MORNING. .LONG TERM...BACK EDGE OF MID LEVEL TROUGH TO BE EXITING EASTERN COLORADO DURING THE EVENING WITH WEAK SUBSIDENCE SPREADING ACROSS THE AREA. FLOW ALOFT APPEARS A BIT SPLIT WITH WESTERLY FLOW ACROSS SOUTHERN COLORADO AND NORTHWEST FLOW ALOFT OVER NORTHERN COLORADO...WITH THE MAIN BATCH OF SUBTROPICAL MOISTURE TO THE WEST AND SOUTH OF THE CFWA. STILL ENOUGH MOISTURE AND WEAK INSTABILITY DURING THE EVENING FOR SOME THUNDERSTORMS WHILE AIRMASS A BIT MORE STABLE OVER PLAINS. SHOULD SEE STORMS END ACROSS PLAINS AROUND MIDNIGHT AS AIRMASS CONTINUES TO STABILIZE WITH PERHAPS A FEW STORMS LINGERING OVERNIGHT ACROSS THE HIGH COUNTRY. ON FRIDAY...FLOW ALOFT BECOMES MORE WESTERLY BY THE AFTERNOON AS MODEL CONSENSUS SHOWS A WEAK UPPER TROUGH MOVES ACROSS NORTHERN WYOMING. HOWEVER...700 MB LOW IS STILL MORE SOUTHWEST...WHICH SHOULD ALLOW SOME INCREASE IN SUBTROPICAL MOISTURE OVER THE AREA. SURFACE HIGH TO PUSH ACROSS INTO CENTRAL PLAINS WITH LOW LEVEL FLOW BECOMING SOUTHEAST BY THE AFTERNOON. THIS WILL ALLOW SOME INCREASE IN LOW LEVEL MOISTURE ALONG WITH SLIGHTLY COOLER TEMPERATURES. FORECAST SOUNDINGS SHOW A BIT OF A CAP ACROSS THE PLAINS. SO BEST CHANCE FOR THUNDERSTORMS TO OCCUR ACROSS THE MOUNTAINS AND FOOTHILLS DURING THE AFTERNOON AND EVENING WITH MOST STORMS ENDING AROUND MIDNIGHT. ON SATURDAY...SOUTHWEST FLOW ALOFT TO PREVAIL WITH SOME INCREASE IN SUBTROPICAL MOISTURE...WHICH SHOULD LEAD TO A CHANCE OF THUNDERSTORMS OVER THE HIGH COUNTRY. ACROSS PLAINS...AIRMASS STILL FAIRLY CAPPED AS NOTED BY FORECAST SOUNDINGS WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT. SOUTHEAST SURFACE WINDS OVER EASTERN COLORADO TO PREVAIL BY THE THE AFTERNOON WITH SOME HINTS OF A DENVER CYCLONE WHICH MAY INCREASE STORM CHANCES EAST AND SOUTH OF DENVER. TEMPERATURES TO WARM IN THE LOWER 80S ACROSS THE PLAINS. FOR SUNDAY...SOUTHWEST FLOW ALOFT TO CONTINUE WITH WEAK UPPER TROUGH MOVING ACROSS CENTRAL PLAINS. MODELS SHOW WEAK FRONT MOVING ACROSS THE PLAINS BY THE AFTERNOON WITH SOME INCREASE IN LOW LEVEL MOISTURE. HOWEVER THE BEST INSTABILITY LOOKS TO BE EAST OF COLORADO. BEST CHANCE FOR THUNDERSTORMS TO BE ACROSS MOUNTAINS WITH A SLIGHT CHANCE OVER THE PLAINS. HIGHS ACROSS PLAINS LOOK TO BE IN THE LOWER 80S. FOR THE LATER DAYS...MONDAY THROUGH WEDNESDAY: MODELS SHOW UPPER LEVEL RIDGE BUILDING ACROSS COLORADO WITH A GRADUAL DECREASE IN SUBTROPICAL MOISTURE. THIS TO LEAD TO A DECREASING CHANCE OF THUNDERSTORMS AND SLIGHTLY WARMER TEMPERATURES. && .AVIATION...WEAK WIND SHIFT WENT BY DIA EARLIER BUT OTHERWISE A GENERAL SOUTHEAST FLOW EXPECTED UNTIL LATER IN THE EVENING. MOST IF NOT ALL THUNDERSTORMS SHOULD REMAIN SOUTH AND EAST OF THE AIRPORT AS IT LOOKS NOW. && .HYDROLOGY...GIVEN THE DEVELOPMENT TO OUR SOUTH AS NOTED ABOVE WITH PUB GETTING ALMOST AN INCH OF RAIN IN A SHORT TIME THE THREAT OF FLASH FLOODING STILL IN PLACE SO CONTINUE THE WATCH FOR THE PALMER DIVIDE REGION. && .BOU WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ041-046-047. && $$ SHORT TERM...SZOKE LONG TERM....D-L AVIATION...SZOKE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
320 PM MDT WED AUG 7 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 320 PM MDT WED AUG 7 2013 COMPLEX WEATHER PATTERN AFFECTING THE REGION THIS AFTERNOON. AT THE SURFACE THERE IS A WEAK QUASI STATIONARY FRONTAL BOUNDARY DRAPED NEAR THE WY BORDER. ALOFT AND STUCK IN AN UPPER LEVEL RIDGE AXIS IS A SHORTWAVE TROUGH CENTERED IN SOUTH CENTRAL UT. WHILE THE CENTER OF ROTATION WILL STRUGGLE TO MOVE EAST TONIGHT AS EVIDENCED BY THE RAP MODEL...ITS TROUGH WILL ROTATE NORTHEAST INTO SOUTHERN CO. AXIS OF GREATEST INSTABILITY...MUCAPES 1000 TO 2000 J/KG... EXTENDS ALONG THE CO/NM BORDER AT THIS TIME AND THIS INDEED IS WHERE THE MOST VIGOROUS CONVECTION HAS DEVELOPED. THESE STORMS WILL MOVE NORTHEAST INTO SOUTHWEST CO AND INTO THE SAN JUAN MTNS THROUGH EARLY EVENING. MEANWHILE...RAINFALL ASSOCIATED WITH THE CENTER OF ROTATION ACROSS SRN UT WILL ALSO MOVE EAST. OBSERVED RAINFALL RATES SO FAR THIS AFTERNOON HAVE BEEN 0.2 TO 0.3/HOUR IN PARTS OF THE SAN JUANS AND IN THE CENTRAL MTNS. EXPECT EVEN HIGHER RATES TO OCCUR WITH THE STRONG CONVECTION. SO FLASH FLOOD WATCH LOOKS GOOD AND WILL REMAIN IN EFFECT THROUGH MIDNIGHT. THERE IS A MID LEVEL SHEAR AXIS BASICALLY ALONG I-70 WITH DRIER AIR TO THE NORTH. CONSEQUENTLY CONVECTION NORTH OF I-70 WILL BE LESS ROBUST. EXPECT SHOWERS TO DIMINISH OVERNIGHT BUT LINGER OVER THE CENTRAL AND SOUTHERN AREAS TO SOME EXTENT. ON THURSDAY...THE SHORTWAVE SHOULD BE EAST OF THE AREA WITH THE RIDGE AXIS AGAIN DOMINATING. HOWEVER...THERE WILL STILL BE MID TO HIGH LEVEL MOISTURE TRAPPED UNDER THE RIDGE...SO EXPECT ISOLATED TO SCATTERED CONVECTION DIURNAL CONVECTION WEST TO NUMEROUS STORMS EAST...FOCUSED ON THE USUAL HIGHER TERRAIN LOCATIONS. SLIGHTLY LESS CLOUD COVER INITIALLY ON THURSDAY WILL HELP TEMPS RISE A LITTLE QUICKER AND HIGHER THAN TODAY...THOUGH STILL REMAIN BELOW NORMAL. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 320 PM MDT WED AUG 7 2013 THE LARGE SCALE PATTERN CHANGES LITTLE AS A LOW PRESSURE TROUGH CONTINUES TO SIT ALONG THE WEST COAST...AND HIGH PRESSURE REMAINS PARKED OVER TEXAS. AFTER A BRIEF PERIOD OF NORTH/NORTHWEST FLOW BEHIND TODAY`S DISTURBANCE...SOUTHERLY FLOW WILL QUICKLY BECOME REESTABLISHED ON FRIDAY. HOWEVER MODELS CONTINUE TO ADVERTISE A MODEST DROP IN MOISTURE ACROSS THE AREA. THESE SOMEWHAT DRIER CONDITIONS WILL THEN PERSIST THROUGH THE EARLY PART OF NEXT WEEK. PRECIPITABLE WATER WILL DROP FROM TODAY`S VALUES OF 0.6-1.0 INCH ...NORTH-SOUTH/CENTRAL TO MORE LIKE 0.4-0.6 INCH ACROSS MOST OF THE AREA. THE LATEST MODEL RUNS HAVE DELAYED FURTHER DRYING UNTIL AROUND MIDWEEK. BETTER SUNSHINE AND THIS MODEST AMOUNT OF MOISTURE WILL STILL RESULT IN ISOLATED TO SCATTERED AFTERNOON SHOWER AND THUNDERSTORM DEVELOPMENT...BUT THIS WILL GENERALLY BE TIED TO THE HIGHER TERRAIN IN THIS DRIER ENVIRONMENT. ONE WEAK DISTURBANCE WILL PASS ACROSS ID/WY AROUND THE TOP OF THE RIDGE ON FRIDAY FOR A LITTLE ENHANCEMENT ACROSS THE NORTH...OTHERWISE THE SOUTH WILL BE FAVORED. THE 12Z GFS AND ECMWF RUNS SHOW GOOD AGREEMENT WITH THIS PERSISTENT PATTERN...AND AS THE HIGH EVENTUALLY SHIFTS WEST INTO SOUTHERN NM/AZ BY THE MIDDLE OF NEXT WEEK. AS THE HIGH REACHES SOUTHERN NM...IT WILL TEND TO BLOCK THE SUBTROPICAL MOISTURE STREAM. THEREFORE LOOK FOR ANOTHER NOTCH OF DRYING. IN SPITE OF GOOD MODEL AGREEMENT...SUBSEQUENT MODEL RUNS HAVE SLOWED THE DRYING TREND. THEREFORE CONFIDENCE IS NOT OVERLY HIGH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 320 PM MDT WED AUG 7 2013 PREVAILING CONDITIONS AT TAF SITES WILL BE VFR. HOWEVER WITH THE SLOW MOVING UPPER LEVEL WAVE ACROSS SE AZ AND S CO...SCT TO NUMEROUS SHRA AND TSRA WILL BE OVER THE REGION THROUGH EARLY TONIGHT...MAINLY KMTJ AND SOUTH. AREAS OF MOUNTAIN OBSCURATION IN FOG/SHRA WILL BE EXPECTED. DRIER AIR ALONG AND NORTH OF I-70 WILL KEEP THOSE LOCATIONS WITH RELATIVELY LOWER CHANCES OF CONVECTION. CONDITIONS WILL IMPROVE LATE TONIGHT...WITH A FEW SHOWERS PERSISTING OVER THE SAN JUAN MOUNTAINS INTO THURSDAY MORNING. SHOWERS AND THUNDERSTORMS WILL REDEVELOP AFTER 18Z THURSDAY...FAVORING THE SAN JUAN MOUNTAINS TO THE CENTRAL CONTINENTAL DIVIDE AREA. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ011-012-014- 017>023. UT...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR UTZ022-028-029. && $$ SHORT TERM...BWM LONG TERM...EH AVIATION...BWM
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
106 PM CDT WED AUG 7 2013 .UPDATE... ISSUED AT 105 PM CDT WED AUG 7 2013 COLD FRONT CONTINUES TO SAG TO THE SOUTHEAST AND IN THE DVN CWA EXTENDS FROM PUTNAM COUNTY TO HANCOCK COUNTY. A FEW SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ALONG AND AHEAD OF THE FRONT WHICH SHOULD EXIT THE CWA EARLY THIS AFTERNOON. ELSEWHERE...A BAND OF LOW CLOUDS WAS DROPPING SOUTHEAST INTO OUR FAR NW CWA BUT WAS ERODING/THINNING ON THE SOUTH EDGE. TEMPERATURES HAVE REACHED THEIR PEAK AND ARE EXPECTED TO STEADY OUT. DEWPOINTS WILL ALSO GRADUALLY LOWER THROUGH THE AFTERNOON WITH NORTHWEST TO NORTH WINDS ADVECTING SOMEWHAT DRIER AIR INTO THE CWA. UPDATE ISSUED AT 1020 AM CDT WED AUG 7 2013 A FEW THUNDERSTORMS HAVE DEVELOPED ALONG THE COLD FRONT FROM JUST NORTHWEST OF MACOMB TO NEAR KEWANEE AND WERE MOVING EAST/NORTHEAST. SOME OF THE STORMS WILL PRODUCE BRIEF HEAVY RAINFALL. THE FRONT WILL CONTINUE TO SAG TO THE SOUTHEAST OF THE CWA BY NOON OR 1 PM. THE HRRR MESO MODEL INDICATES THE FRONT BECOMING MORE ACTIVE BY EARLY THIS AFTERNOON BUT BY THEN THE FRONT SHOULD BE SOUTHEAST OF THE DVN CWA. OTHERWISE...BEHIND THE FRONT WINDS WILL TURN NORTHWEST TO NORTH WITH GRADUALLY LOWERING DEW POINTS. CANADIAN HIGH WILL BUILD INTO THE REGION TONIGHT AND THURSDAY WITH MUCH MORE COMFORTABLE TEMPERATURES AND HUMIDITY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 322 AM CDT WED AUG 7 2013 WESTERN GRT LKS FRONTAL SYSTEM TO CONTINUE TO SWEEP THROUGH THE AREA THIS MORNING AND WILL WALK OUT ANY LINGERING CONVECTION/STORM CLUSTERS THROUGH 14Z TO 16Z...MAY DECAY BEFORE THEN LIKE LATEST HIRES MODEL RUNS SUGGEST. DESPITE FROPA...SOME LAG IN LLVL COOLER AIR ADVECTION AND EXPECT TEMPS TO WARM INTO THE LOW TO MID 80S IN THE SOUTHEASTERN HALF OF THE DVN CWA...UPPER 70S IN THE NORTHWESTERN FCST AREA. THESE TEMPS BANKING ON CONVECTIVE DEBRIS ERODING DIURNALLY. A BOUT OF PASSING SFC RIDGING WILL MAKE FOR A MAINLY CLEAR SKY AND COOLER TEMPS TONIGHT WITH SOME 50S OCCURRING NORTH OF I80. VALLEY FOG POSSIBLE. .LONG TERM...(THURSDAY THROUGH NEXT TUESDAY) ISSUED AT 322 AM CDT WED AUG 7 2013 GENERALLY BELOW NORMAL TEMP REGIME CONTINUES. MAIN STORY AT THE END OF THE WEEK WILL BE ACTIVE GRT BSN AND SOUTHERN STREAM FLOWS LOADED WITH MONSOONAL MOISTURE AND IF SOME OF IT CAN MAKE IT THIS FAR NORTH. LATEST MODEL TRENDS CONTINUE TO SHOW SOME PHASING POTENTIAL WITH NORTHERN PLAINS/UPPER MIDWEST TROFFINESS WHICH WOULD INDUCE SOME LLVL CYCLOGENESIS ACRS THE SOUTHERN PLAINS OVER TO THE MID MS RVR VALLEY. TIMING OF THIS PROCESS AND HOW FAR NORTH IT CAN MAKE IT STILL UNCERTAIN WITH MODEL VARIABILITY...BUT SIGNALS ARE THERE THAT AT LEAST THE SOUTHERN THIRD TO HALF OF THE CWA MAY GET IN ON SOME OVERRUNNING PRECIP/SOME POTENTIALLY DECENT SOAKING RAINS/ AT WEEKS END. THE 00Z GFS AND UKMET TARGET LATE THU NIGHT INTO FRIDAY...WHILE THE 00Z ECMWF IS POINTING AT FRI NIGHT AND NOT AS FAR NORTH AS THE PREVIOUS MENTIONED MODELS WITH IT/S PRECIP SWATH. MAY TREND TOWARD THE UKMET AND GFS WITH POPS INCREASING IN THE SOUTH THU NIGHT INTO FRI FOR NOW. BUST POTENTIAL FOR ADVERTISED TEMPS TO BE TOO WARM IN THE SOUTH HALF IF THIS MATERIALIZES BECAUSE OF PRECIP AND CLOUD COVER ESPECIALLY ON FRI. TELECONNECTION PERSISTENCE...THE GENERAL PATTERN OF NORTHWEST FLOW ALOFT WITH RE-ENFORCING DUMPS OF CANADIAN HIGHS DOWN THE UPPER MIDWEST AND WESTERN GRT LKS OVER THE WEEKEND AND INTO MID NEXT WEEK. SOME CHANCE OF A NORTHWEST FLOW PRECIS EVENT IN ONE OF THESE TRANSITIONS...WITH ONE WINDOW OF OPPORTUNITY LOOKING LIKE SUNDAY NIGHT INTO MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 105 PM CDT WED AUG 7 2013 MAINLY VFR CONDS THROUGH THURSDAY MORNING. HOWEVER MVFR BR 10-15Z/08 AT KBRL. NORTHWEST TO NORTH WINDS AROUND 10 KNOTS THIS AFTERNOON WITH WINDS BECOMING NORTHEAST TO EAST AT LESS THAN 10 KNOTS TONIGHT INTO THURSDAY. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...HAASE SHORT TERM...12 LONG TERM...12 AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 PM MDT WED AUG 7 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 221 PM MDT WED AUG 7 2013 LATEST WV IMAGERY AND RAP H5 ANALYSIS INDICATES ZONAL FLOW STILL IN PLACE ACROSS THE CONUS WITH STRONG CLOSED LOW OVER CENTRAL CANADA. AN EMBEDDED H5/H7 LOW IN IN PLACE UPSTREAM OF THE CWA OVER THE FOUR CORNER REGION. LARGE SCALE FORCING AND MID LEVEL MOISTURE CONTINUE TO ADVECT INTO THE CWA FROM THE SOUTHWEST AHEAD OF THE FOUR CORNERS TROUGH. RAP ANALYSIS STILL SHOWS 500-1500 J/KG OF MUCAPE IN PLACE...SO THUNDERSTORMS ARE CERTAINLY POSSIBLE. AT THIS POINT OVERALL THREAT FOR SEVERE THUNDERSTORMS SEEMS LOW. MODELS CONTINUE TO PAIN BULLS EYE OF 0.50+ QPF...FAVORING SOUTHERN LOCATIONS. AT THE SAME TIME...NAM/SREF HAVE TRENDED FURTHER NORTH WHICH DOES SEEM TO HAVE SUPPORT LOOKING AT LATEST RADAR TRENDS. I ADJUSTED POPS ACCORDINGLY. RAP INDICATES PWATS IN EXCESS OF 1.3"...AND WHILE LOWER THAN THE LAST FEW DAYS IS STILL CLIMATOLOGICALLY HIGH. BASED ON RADAR/SATELLITE TRENDS...AND THE NATURE OF THIS PATTERN...I AM CURRENTLY EXPECTING SEVERAL PERIODS OF SHOWERS/THUNDERSTORMS ROTATING ACROSS OUR CWA THROUGH TONIGHT...BEFORE THE MAIN TROUGH MOVES ACROSS THE REGION. AS THIS OCCURS WE MIGHT SEE OUR BEST CHANCE FOR HEAVY PRECIP ACROSS MOST OF THE CWA. THERE IS STILL SOME INDICATION THIS COULD OCCUR LATER IN THE DAY THURSDAY...HOWEVER CONSENSUS SUPPORTS A MORNING TROUGH PASSAGE AND DECREASING CHANCES THROUGH MIDDAY THURSDAY. REGARDING WATCH...CONSIDERING THE LIKELIHOOD THAT PRECIPITATION WILL REMAIN LIGHT TO MODERATE ACROSS MOST OF THE AREA WITH HIGHEST TOTALS SPREAD OUT OVER 6-12HR PERIOD...I AM STARTING TO QUESTION THE POTENTIAL FOR FLASH FLOODING. LATEST 6HR FLASH FLOOD GUIDANCE IS GENERALLY IN THE 2-3 INCH RANGE OVER THE WATCH AREA AND UNLESS WE CAN GET A STRONG THUNDERSTORM EMBEDDED WITHIN THE LARGER AREA OF LIGHT-MODERATE RAIN IM NOT SURE WE WILL SEE THESE RATES. WE MAY BE ABLE TO CANCEL THE WATCH LATER THIS EVENING...BUT I WOULD RATHER WAIT AND SEE HOW CONVECTION EVOLVES. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 221 PM MDT WED AUG 7 2013 THURSDAY EVENING THE UPPER LEVEL SHORT WAVE TROUGH WILL MOVE EAST OF THE AREA. WITH THE NOSE OF THE LOW LEVEL JET OVER THE EASTERN PART OF THE AREA AS WELL...AND A WEAK RIGHT ENTRANCE REGION OF THE 300MB JET OVER THE AREA...THERE MAY BE SOME LINGERING PRECIP. ACTIVITY AHEAD OF THE EXITING TROUGH. MEANWHILE BEHIND THE TROUGH DRIER AIR WILL BE MOVING IN WHICH WILL CAUSE PRECIP. CHANCES TO DECLINE FROM WEST TO EAST. HOWEVER WITH COOLER AIR MOVING IN THERE WILL BE SOME INSTABILITY LINGERING BEHIND THE TROUGH. WITH SOME MUCH SMALLER UPPER LEVEL DISTURBANCES MOVING THROUGH BEHIND THE MAIN FEATURE...ISOLATED STORMS CANNOT BE RULED OUT DURING THE EVENING AND INTO THE OVERNIGHT HOURS. FRIDAY ANOTHER UPPER LEVEL SHORT WAVE TROUGH WILL DEVELOP OVER FAR EASTERN COLORADO IN THE LATE AFTERNOON. AT THE SURFACE A TROUGH WILL BE OVER THE WESTERN BORDER OF THE TRI-STATE AREA BENEATH THE SHORT WAVE. WITH SURFACE CONVERGENCE AND UPPER LEVEL LIFT...ANTICIPATE SOME STORMS DEVELOPING ALONG THE SURFACE TROUGH DURING THE MID AFTERNOON INTO THE EARLY EVENING. MEAN STORM MOTIONS WILL BE VERY SLOW...WITH MOTIONS TURNING FROM THE WEST TO THE NORTH. THESE MOTIONS WILL KEEP THE STORMS CONFINED TO THE SURFACE TROUGH. BY THE LATE EVENING ANY STORMS THAT DEVELOPED WILL DISSIPATE AS THE ENVIRONMENT STABILIZES. THE MAIN THREAT WITH ANY STORMS THAT DEVELOP WILL BE HEAVY RAINFALL. SATURDAY THROUGH WEDNESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST CONUS WILL SLOWLY BUILD NORTHWARD...WITH THE TRI-STATE AREA REMAINING UNDER THE PERIPHERY OF THE RIDGE. AS A RESULT MULTIPLE UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE OVER THE AREA THROUGH THE PERIOD. THE STRONGER TROUGHS WILL MOVE OVER THE AREA AFTER THE WEEKEND. MEANWHILE A FRONT WILL WAFFLE BACK AND FORTH OVER THE AREA DURING THIS PERIOD WHICH WILL CAUSE TEMPERATURES TO VARY SOMEWHAT. AT THIS TIME RANGE DIFFICULT TO KNOW WHERE THE FRONT WILL BE SO WILL KEEP THE CONSENSUS TEMP. FORECAST OF NEAR NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1145 AM MDT WED AUG 7 2013 VFR CONDITIONS SHOULD PREVAIL AT BOTH TERMINALS THROUGH THE VALID TAF PERIOD. MVFR/IFR CONDITIONS CANT BE RULED OUT IF A STRONGER THUNDERSTORM WERE TO OCCUR...HOWEVER CONFIDENCE IS TOO LOW TO ADD MENTION AT THIS TIME. SHOWERS/THUNDERSTORMS ARE EXPECTED TO SPREAD EAST THROUGH THE AFTERNOON WITH BEST CHANCES AT BOTH TERMINALS THROUGH THIS EVENING...THOUGH THIS ACTIVITY COULD POSSIBLY LINGER ALL NIGHT. ADDITIONAL SHOWERS/THUNDERSTORMS MAY DEVELOP THURSDAY MORNING...I WAS NOT CONFIDENT ENOUGH TO PREVAIL THE CONDITIONS THU MORNING AT EITHER TERMINAL. INSTEAD I INCLUDED VCSH THROUGH THE REMAINING TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR KSZ027>029-041- 042. CO...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR COZ092. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JTL AVIATION...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
111 PM CDT Wed Aug 7 2013 ...UPDATED FOR THE AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1229 AM CDT WED AUG 7 2013 At 00z Wednesday a +100kt 250mb jet extended from South Dakota into the western great lakes. The right entrance region was located near central Nebraska/northern Kansas. At the 500mb level an upper level trough was located over eastern Montana and an upper level ridge axis was located across the pacific northwest. Further south over the southern plains an upper high was located near the gulf coast of Texas and an upper level low/trough moved northward out of Mexico into eastern Arizona. Convection that developed across southwest Kansas near the Colorado border around 00z Wednesday was currently moving east/southeast across south central Kansas at 05z. These storms appeared to located where the better 850mb moisture, frontogenesis, and warm air advection were occurring earlier this evening. Further north another area of convection had developed during the evening hours from northeast Colorado into western Nebraska. This a located near a surface trough of low pressure and where better moist upslope flow was present along with better mid level lapse rates. RAP also hinted at a subtle upper level wave was located in this area at 00z. && .SHORT TERM...(Today and tonight) ISSUED AT 251 AM CDT WED AUG 7 2013 The NAM, RAP, GFS were all in decent agreement this morning with moving an upper level trough across northern Kansas early this morning. Based on the 06z location of this upper wave it appears that an area of convection had developed ahead of this system based on the composite radar loop. Given this and the timing of the upper level trough will raise precipitation chances in the north to at least high chance for early this morning. Further south the chances for convection early will be less but still given weak lift forecast across southwest Kansas will keep some small pops going early today. Convection should briefly taper off as the upper level trough passes east of the area, however by the early afternoon the chances for convection will begin to improve, especially across far western and southwest Kansas where moist upslope flow is expected and better afternoon instability and 0-6km shear is forecast to be located. Convection will then increase in areal coverage as it spreads east across the remainder of western Kansas late today and overnight as the Arizona upper low/trough moves east across New Mexico. Heavy rainfall will still be an issue later today and overnight given the precipitable water content on the Dodge City soundings at 1.42 inches at 00z Wednesday. Also strong damaging winds and large hail will be possible from some these storms late today and early tonight. The flood watch currently in the effect still looks on track given several opportunities of heavy precipitation later today through Thursday. .LONG TERM...(Thursday through Tuesday) ISSUED AT 315 AM CDT WED AUG 7 2013 A cool and wet period is forecast for the area with much above average forecaster certainty for significant measurable rainfall through Thursday. The synoptic set up includes an already very moist atmosphere across the central high plains, characterized by dew points in the 60s and 70s. Additionally, and upper high center over the Southern Plains and Gulf region helping transport additional pacific moisture poleward. The kinematic fields will include the slow development of a Central Rockies through which will place Western Kansas under a favorable positive vorticity and warm advection region for maximum lift potential Thursday. Additionally, a surface/850 mb frontal zone will air in low level frontogenesis adding to the QG component. These elements have given enough confidence to raise precipitation chances into the categorical range during the day 2 period. The slow nature of this existing wave will create a fluid forecast situation . The jet streak will still leave a broad right rear quadrant entrance region into Friday, and thunderstorm cannot be ruled out through this period as well, although the trend would be downward. During this period it is likely that a widespread one to two inches of rain will fall over the entire southwest and central Kansas region. Areas of higher rainfall perhaps in excess of 5 inches are possible based on model run totals, but with relatively low forecaster confidence with respect to coverage. From Friday and onward increased ridging along the High Plains region will create a warming trend with opportunities for severe weather producing MCS events into early next week. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) ISSUED AT 105 PM CDT WED AUG 7 2013 MVFR Cigs have moved into the kddc area, and will likely spread west and north as the afternoon and evening progress. Scattered thunderstorms are also expected to develop, but will only be carried in the Tafs as vcsh until after 01z. Then a tempo group for 2sm +tsra will cover the period from 01z to 05z. Cigs from 01-05Z should remain in the Mvfr ovc040 range. && .PRELIMINARY POINT TEMPS/POPS... DDC 66 72 65 78 / 90 80 60 30 GCK 65 71 65 77 / 90 80 60 30 EHA 65 73 62 80 / 70 80 50 30 LBL 67 75 64 80 / 80 80 50 30 HYS 65 76 65 76 / 90 80 70 40 P28 69 78 66 81 / 70 80 50 30 && .DDC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066- 079-081. && $$ SYNOPSIS...BURGERT SHORT TERM...BURGERT LONG TERM...RUSSELL AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS JACKSON KY
152 PM EDT WED AUG 7 2013 .UPDATE... ISSUED AT 151 PM EDT WED AUG 7 2013 UPDATED TO NDFD FOR LATEST OBSERVATIONAL TRENDS. BASED ON CURRENT RADAR TRENDS HAVE TAPERED THE NUMEROUS SHOWERS IN THE EAST TO SCATTERED A LITTLE QUICKER THAN PREVIOUS FORECAST. CONVECTIVE COVERAGE LOOKS TO REMAIN SCATTERED ACROSS THE ENTIRE AREA FOR THE REMAINDER OF THE AFTERNOON WITH MORE SHOWERS THAN THUNDERSTORMS. UPDATE ISSUED AT 1147 AM EDT WED AUG 7 2013 NDFD AND ZFP HAVE BEEN UPDATED. WHILE THE EARLY MORNING RUNS OF THE HRRR DID NOT DO A VERY GOOD JOB HANDLING THE CONVECTION THIS MORNING...THE 12 NAM SEEMS TO HAVE A BETTER HANDLE ON THINGS. BASED ON CURRENT TRENDS THE NUMEROUS SHOWERS IN THE SOUTHEAST WILL CONTINUE FOR THE NEXT FEW HOURS...WITH SCATTERED THUNDERSTORMS POSSIBLE ANYWHERE IN THE FORECAST AREA AS WE MOVE INTO THE AFTERNOON. HAVE ADJUSTED AFTERNOON CONVECTIVE COVERAGE TO NUMEROUS IN THE SOUTHEAST AND SCATTERED ELSEWHERE. AFTERNOON TEMPERATURES AND EXTENT OF CONVECTIVE DEVELOPMENT WILL BE ALMOST ENTIRELY DEPENDENT ON SKY COVER. STILL EXPECT ENOUGH BREAKS TO ALLOW TEMPERATURES TO RISE INTO THE LOWER 80S IN MOST AREAS. UPDATE ISSUED AT 956 AM EDT WED AUG 7 2013 NDFD AND ASSOCIATED PRODUCTS...INCLUDING ZFP HAVE BEEN UPDATED. THE NEAR TERM MODELS ARE NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...AND AS SUCH THIS THROWS DOUBT INTO THE NEAR TERM GUIDANCE FOR THE REST OF THE DAY INTO TONIGHT. THE 11Z HRRR SHOWED THE DEVELOPMENT OF THE CONVECTION EARLY THIS MORNING BUT QUICKLY HAD IT DIE AWAY BEFORE BRINGING AN ORGANIZED BAND OF CONVECTION ACROSS THE AREA FROM LATE MORNING INTO EARLY AFTERNOON WITH ANOTHER ROUND OF ORGANIZED CONVECTION FROM LATE AFTERNOON INTO THE EVENING. THE 12Z HRRR IS JUST COMING IN...AND STILL NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...BUT IS LEANING TOWARDS MORE DISORGANIZATION IN THE CONVECTION FOR THIS AFTERNOON. THERE WILL BE CONSIDERABLE DEBRIS CLOUDINESS ACROSS THE AREA TODAY...BUT EXPECT SOME BREAKS IN THE CLOUDS IN THE WAKE OF THE SHOWERS AND THUNDERSTORMS THAT OCCUR THIS MORNING. THIS WOULD ALLOW ADDITIONAL DESTABILIZATION WITH MORE AFTERNOON HEATING. WHERE BREAKS HAVE OCCURRED IN CENTRAL KY TEMPERATURES HAVE JUMPED INTO THE UPPER 70S AND AS SUCH WILL INCREASE AFTERNOON MAXIMUM TEMPERATURES SEVERAL DEGREES. WITH NUMEROUS SHOWERS ALREADY OCCURRING ACROSS THE AREA HAVE INCREASED RAIN CHANCES FOR THIS MORNING IN ALL BUT THE FAR NORTH...YIELDING NUMEROUS SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR TODAY IN MOST AREAS...RATHER THAN JUST FOR THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 356 AM EDT WED AUG 7 2013 THE ENTIRE FORECAST WILL BE PROGGED BY SUBTLE SHORTWAVES MOVING EASTWARD FROM THE ROCKIES AND GREAT PLAINS...AND IMPACTING KY OR SURROUNDING AREAS. FOR THE SHORT TERM...THE FOCUS WILL BE ON A SHORT WAVE THAT MODEL CONSENSUS HAS REACHING WESTERN KY BY 18Z TODAY...AND EASTERN KY IN THE EVENING AROUND 0Z. ANOTHER LARGER SHORTWAVE WILL THEN APPROACH WESTERN KY AND MUCH OF TN THE FOLLOWING AFTERNOON ON THURSDAY. BOTH OF THESE WAVES WILL TRANSLATE TO SURFACE INSTABILITY AND THE EXPECTATION OF CONVECTIVE DEVELOPMENT. STARTING WITH TODAY...A WARM FRONT THAT MOVED THROUGH LAST NIGHT HAS ALLOWED FOR STRONG WAA AND A VAST INCREASE IN THE HUMIDITY VALUES. WHILE EXPECTED CLOUD COVER TODAY WILL KEEP TEMPERATURES FROM RISING TO THEIR FULL POTENTIAL...DEW POINTS ON THE OTHER HAND WILL RISE TO THE LOW 70S...ALLOWING FOR HIGH HUMIDITY AND APPARENT TEMPERATURES IN THE MID AND UPPER 80S IN SOME LOCATIONS. THE SHORTWAVE APPROACHING FROM THE WEST WILL TRANSLATE TO A SURFACE LOW PRESSURE SYSTEM TO THE NORTH OVER THE UPPER GREAT LAKES. AS THIS SHORTWAVE AND ASSOCIATED LOW PRESSURE SYSTEM CONTINUE ON THEIR TREK NORTHEAST...IT WILL PULL A LARGE COLD FRONT SEWARD ACROSS MI/IN/IL/AND MO DURING THE AFTERNOON...NEARING THE OHIO VALLEY WEDNESDAY NIGHT. WITH THE VERY MOIST AND UNSTABLE ENVIRONMENT ALREADY AT PLAY DURING THE DAY TODAY...THE ISENTROPIC LIFT AHEAD OF THE APPROACHING FRONT WILL BE ENOUGH TO KICK START CONVECTION ACROSS THE AREA. WHILE MODELS ARE STILL SOMEWHAT LACKLUSTER ON THEIR SOLUTION AGREEMENT...WILL GO WITH THE CONSENSUS THAT BEST PRECIP POTENTIAL WILL BE IN THE FAR EASTERN PORTION OF THE CWA BETWEEN 15 AND 0Z TODAY. WITH GOOD DIRECTIONAL AND SPEED SHEAR...AS WELL AS MARGINAL CAPE VALUES...COULD SEE STORMS DEVELOP ACROSS THE ENTIRE CWA. WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN THE MID AND UPPER LEVELS...COULD SEE SOME POTENTIAL FOR STRONG WINDS AND SMALL HAIL DEVELOPMENT IN ADDITION TO SOME HEAVY DOWNPOURS. BEST CONVECTIVE ACTIVITY WILL DIE DOWN OVERNIGHT WITH LOSS OF DAYTIME HEATING...BUT AS COLD FRONT JUST TO OUR NORTH BECOMES NEARLY STATIONARY...THERE WILL BE ENOUGH INSTABILITY AND LIFT NEARBY TO PREVENT DROPPING POPS BELOW CHANCES. THIS WILL BE REINFORCED BY THE FACT THAT CLOUD COVER AND CONTINUED WARM AIR FILTERING IN FROM THE SOUTH WILL PREVENT LOWS FROM DROPPING BELOW 70 IN MANY LOCATIONS. THIS WILL RESULT IN A VERY SOUPY NIGHT WITH HUMIDITY VALUES RANGING FROM 90 TO 100 PERCENT ACROSS MUCH OF THE REGION. ANY LITTLE THING COULD BE ENOUGH TO INITIATE SOME SORT OF PRECIP IN SUCH AN ENVIRONMENT AS A RESULT. BY 12Z THURSDAY...THE NEXT SHORTWAVE TO IMPACT THE AREA WILL FIND ITSELF OVER MISSOURI AND NORTHERN ARKANSAS. AT THE SURFACE...THIS WILL BEGIN INTERACTING WITH THE STATIONARY SURFACE COLD FRONT AND THE DAYTIME INSTABILITY...BRINGING AN INCREASE OF CONVECTION ACROSS WESTERN KY IN THE MORNING...AND THEN ACROSS THE ENTIRE FRONTAL BOUNDARY BY AFTERNOON...WITH PRECIP CHANCES EXPECTED TO IMPACT FROM AS FAR WEST AS COLORADO...THEN POINTS EASTWARD...AND ACROSS THE ENTIRETY OF THE EASTERN SEABOARD. ONCE AGAIN...MODEL CONSENSUS IS PEGGING THE FAR EASTERN PORTIONS OF THE STATE FOR THE BEST QPF AND PRECIP POTENTIAL...THOUGH IN SUCH AN ENVIRONMENT SCT TO WIDESPREAD STORM DEVELOPMENT CAN BE EXPECTED JUST ABOUT ANYWHERE ACROSS THE REGION. CAPE VALUES THIS DAY WILL BE MUCH MORE SUBSTANTIAL IN THE EAST CENTRAL...WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN ALOFT DURING THE AFTERNOON HOURS. THE LATEST ECMWF IS ALSO SHOWING THAT WHILE LAPSE RATES WILL STILL NOT BE THAT IMPRESSIVE...THERE WILL BE A GOOD AREA OF QVECTOR CONVERGENCE THAT MOVES ACROSS THE STATE THURSDAY AFTERNOON/EVENING. ALL THINGS BEING FACTORED IN...LATEST NAM SOUNDINGS SUPPORT THE IDEA THAT WITH LITTLE IN THE WAY OF LAPSE RATES AND PWAT VALUES NEARING 2 INCHES IN SOME PLACES...WILL PROBABLY EXPECT MORE OF A HEAVY RAIN THREAT WITH THESE STORMS COMPARED TO TODAY. SOME ISOLATED STRONGER STORMS CAN NOT BE RULED OUT HOWEVER. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 356 AM EDT WED AUG 7 2013 THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN ALOFT FOR THE EXTENDED. LIKE LAST NIGHT...THE MAIN DIFFERENCES REVOLVE AROUND SHORTWAVES AND MESOSCALE FEATURES THAT ARE MORE DIFFICULT TO RESOLVE THIS FAR OUT. THE GENERAL PATTERN STARTS WITH A DOMINANT TROUGH OVER SOUTH CENTRAL CANADA NORTH OF FLAT RIDGING COVERING THE SOUTHERN TIER OF THE STATES. BETWEEN THESE...RELATIVELY FAST FLOW WILL BRING ENERGY FROM THE WEST COAST TO THE EAST PASSING THROUGH THE OHIO VALLEY. WHILE THE CORE OF THE NORTHERN TROUGH MOVES EAST BY EARLY SATURDAY THE TROUGH ITSELF WILL REFORM OVER THE WEEKEND AND ACTUALLY BUILD SOUTH TO ENCOMPASS THE GREAT LAKES OHIO VALLEY BY 00Z TUESDAY. OVER OUR AREA THIS EVOLUTION WILL BUCKLE THE INITIALLY ZONAL PATTERN INTO ONE OF NORTHWEST FLOW. THROUGH IT ALL...KENTUCKY WILL HAVE TO DEAL WITH PASSING WAVES OF MID LEVEL ENERGY ALONG WITH ANY THAT MAY BE CONVECTIVELY DRIVEN. THIS SHOULD MEAN AN LARGELY UNSETTLED PERIOD OF WEATHER. DUE TO THE GENERAL MODEL AGREEMENT...HAVE FAVORED A MODEL BLEND WITH A BIT OF A LEAN TOWARD THE 00Z ECMWF. SENSIBLE WEATHER WILL FEATURE AN EXTENDED PERIOD OF POTENTIALLY EXCESSIVE RAINS AS A FRONTAL BOUNDARY AND HIGHER THAN NORMAL PW AIR WILL REMAIN IN IN PLACE THROUGH THE WEEKEND. COMBINED WITH DAYTIME INSTABILITY...AND SOME UPPER LEVEL SUPPORT...EACH DAY COULD TURN OUT TO BE A WASHOUT WITH HEAVY RAIN FROM A COMPLEX OF SHOWERS AND THUNDERSTORMS. HOWEVER...SIMILAR TO TODAY...SOME OF THESE PARAMETERS MAY NOT COME TOGETHER AND A GOOD PORTION OF THE AREA COULD BE DRY DESPITE THE SET UP. AS SUCH...THE FORECAST WILL CONSIST OF HIGHER POP CHANCES DURING THE LATE AFTERNOON AND EARLY EVENING HOURS WITH A DIMINISHMENT AT NIGHT THROUGH SUNDAY. OF COURSE...ANY MCS ACTIVITY COULD EASILY EXTEND INTO THE NIGHT SO CANNOT GO DRY FOR THESE TIMES EITHER. UNFORTUNATELY...WITH THE POTENTIAL FOR MCS DEVELOPMENT THROUGH THE BULK OF THE EXTENDED...CONFIDENCE IS LOWER THAN NORMAL FOR FORECAST SPECIFICS ASIDE FROM THE ACKNOWLEDGMENT OF THE BUILT UP POSSIBILITIES. THEREFORE...THE FORECAST WILL CONSIST OF RATHER HIGH POPS THROUGH THE WEEKEND...WITH LESS OF A THREAT ON MONDAY AND TUESDAY IF THE NEW ECMWF IS RIGHT AND THE FRONT DROPS SOUTH. ALONG WITH THE HIGH POPS WILL GO COOLER THAN NORMAL TEMPS... THOUGH THE HIGH DEWPOINTS WILL MAKE IT FEEL SEVERAL DEGREES WARMER THAN ACTUAL AIR TEMPERATURE. BASED ON THE 00Z ECMWF...HIGH PRESSURE MAY BE ABLE TO PUSH IN AND SHOVE THE MORE HUMID AIR SOUTH FOR A GOOD PORTION OF THE UPCOMING WEEK. UNTIL THEN...THOUGH...WE WILL BE AWASH IN A MUGGY AIR MASS COMPLETE WITH MOST OF THE INGREDIENTS NEEDED FOR HEAVY RAINS. THE CR GRID LOAD CAME IN PRETTY GOOD FOR THIS CONVECTIVELY UNSETTLED SITUATION. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO TOWARD THE LATEST SPECIFICS FROM THE ECMWF. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS THROUGHOUT THE EXTENDED PERIOD GIVEN THE HIGH MOISTURE CONTENT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 151 PM EDT WED AUG 7 2013 SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE TO AFFECT THE ENTIRE FORECAST AREA FOR THE REMAINDER OF THE AFTERNOON. WITH THE WIDELY SCATTERED NATURE OF THE CONVECTION WILL GO WITH VCTS IN THE TAFS FOR THE REMAINDER OF THE AFTERNOON. THE GENERAL TREND WILL BE FOR CEILINGS TO INCREASE THROUGH THE AFTERNOON INTO THE EVENING WITH MVFR TO VFR CEILINGS THIS AFTERNOON GIVING WAY TO ALL VFR CEILINGS THIS EVENING. CONDITIONS WILL DETERIORATE LATE TONIGHT AND INTO THE DAY ON THURSDAY AS MORE WIDESPREAD SHOWERS AND THUNDERSTORMS MOVE INTO THE AREA IN ADVANCE OF AN APPROACHING COLD FRONT. EXPECT WIDESPREAD MVFR CONDITIONS BY DAYBREAK THURSDAY. CONDITIONS WILL THEN LIKELY IMPROVE LATE IN THE DAY ON THURSDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SBH SHORT TERM...JMW LONG TERM...GREIF AVIATION...SBH
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
302 PM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN PARKED OFFSHORE THROUGH THE END OF THE WEEK. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL MOISTURE UP THE EASTERN SEABOARD. LOW PRESSURE MOVING EAST THROUGH CANADA LATE IN THE WEEK WILL DRAG A COLD FRONT SOUTHEAST INTO THE MID ATLANTIC SATURDAY. THAT FRONT WILL STALL OVER THE AREA INTO EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... A V-SHAPED AREA OF CLEARING OVER THE WRN SECTIONS OF THE CWA - THE WV PORTION OF THE APLCNS - HAS RESULTED IN ENOUGH INSTABILITY COMBINING W/ A WEAK LEE TROUGH TO DEVELOP A HANDFUL OF TSTMS. ATTM...THESE CELLS ARE TRUDGING ALONG THE LOW LEVEL BOUNDARY STATIONED FROM NEAR ELKINS WV TO AROUND WINCHESTER VA. POCKETS OF CLEARING ALSO OCCURRING OVER THE NRN VA PIEDMONT AND I-95 CORRIDOR...WHERE NUMEROUS AND VERY SMALL-SCALE SHOWERS ARE DRIFTING OFF TO THE NE. HAD THERE NOT BEEN THE SOLID STRATUS DECK FOR MUCH OF THE DAY...THIS TYPE OF ACTIVITY WOULD LIKELY BE MUCH MORE WIDESPREAD AND STRONGER...GIVEN THE DEEP MID-LEVEL DRY LAYER AND DECENT LAPSE RATES. WITH SEVERAL MORE HRS OF DAYTIME LEFT...AREAS THAT CONTINUE TO CLEAR OUT WILL ALSO SEE SOME OF THIS SCATTERED SHOWER/ISOLATED TSTM ACTIVITY DEVELOP. THE STRONGEST OF THIS ACTIVITY WILL LIKELY BE LIMITED TO THE POTOMAC HIGHLANDS/APLCNS AND PARTS OF THE NRN VA SHEN VLY THRU THE AFTN/EVE HRS. THE UPPER LEVEL FORCING AND DYNAMICS ARE - AND WILL CONTINUE TO BE MUCH STRONGER THAN THE LOW LEVELS...WHICH MEANS THAT VERY LITTLE LOW LEVEL INTERACTIONS WILL MAKE FOR ONLY A FEW TSTM CELLS BUT THE ONES THAT DEVELOP WILL HAVE HEFTY SUPPORT FOR MAINTENANCE. THE FAVORABLE BULK SHEER WILL ALSO...IN PART...MAKE UP FOR THE RELATIVELY LOW INSTABILITY. IN VARIOUS FORMS AND DEPICTIONS...THE HRRR AND OTHER LOCAL GUIDANCE CONTINUE TO DEVELOPING THE FAIRLY RAGGED AND DISORGANIZED CONVECTIVE LINES IN NRN OH...STRENGTHEN AND DRAG THEM ACROSS THE REMAINDER OF WRN AND CNTRL PA TOWARD THE LATE NIGHT HRS TONIGHT. EACH RUN A LITTLE DIFFERENT BUT STILL HIGHLIGHT THE MASON-DIXON LINE AND THE TIER OF NRN MD COUNTIES ALONG IT AS THE NRN EXTENT OF WHERE THIS LINE COULD SWING ACROSS. KEPT HIGHER POPS ACROSS THE NRN TIER THIS EVE/TONIGHT FOR THIS EVENTUALITY. THOUGH MUCH OF THE LINE COULD DISSIPATE AND BECOME STRATIFORM -SHRA...GUSTY WINDS FROM THE UPPER LEVELS COULD BE A POSSIBILITY FROM EVEN POCKETS OF HEAVY DOWNPOURS. RAISED THE NEAR-TERM FORECAST TEMPS A COUPLE OF DEGREES W/ THE QUICK DISSIPATION OF THE STRATUS DECK. MOST AREAS ARE NOW CLIMBING AT LEAST INTO THE L80S. DEWPOINTS ARE ALSO CHARGING UP INTO THE U60S AND L70S...MAKING FOR WHAT WILL BE A FAIRLY HUMID OVERNIGHT PERIOD. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... THURSDAY BOTH THE EURO AND THE GFS BRING A TROUGH INTO THE REGION FROM THE WEST. IT WILL BE ENOUGH TO AMP UP CHANCES OF THUNDER TO LIKELY ACROSS ALL BUT SOUTHERN MD AND CENTRAL VA. WITH PRECIPITABLE WATER FORECAST TO BE AROUND 2 INCHES AND WITH A FEW HINDERED OF CAPE...THERE COULD BE SOME ISOLATED FLOODING ISSUES OR SEVERE THREAT. NWS STORM PREDICTION CENTER MAINTAINS OUR AREA IN THE 5 PERCENT CHANCE FOR A FEW SEVERE STORMS ON THU. FRI INTO FRI NIGHT WEAK TROF REMAINS OVER THE AREA. WILL MAINTAIN CHANCE POPS OF TSTMS FOR THAT DIFFUSE FORCING. STILL...THERE IS ENOUGH CAPE FOR A FEW ISOLATED SEVERE STORMS POSSIBLE. SPC HAS 5 PERCENT AGAIN. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... SATURDAY LOW PRESSURE WILL BE TRAVELING EAST THROUGH EASTERN CANADA. THE ASSOCIATED COLD FRONT WILL ENTER OUR AREA ON SATURDAY...BUT WILL LIKELY STALL OVER OR VERY NEAR OUR AREA INTO EARLY NEXT WEEK. THAT WILL RESULT IN CHC TO SLIGHT CHC POPS FOR TSTMS RIGHT THRU THIS PART OF THE FORECAST. TEMPS WILL BE NEAR NORMAL. AT THE MOMENT...SATURDAY LOOKS LIKE THE WARMEST DAY WITH HIGHS IN THE UPPER 80S TO LOWER 90S ACROSS THE REGION...BUT THAT WILL DEPEND ON THE FRONT. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... BREAKS IN THE LOW STRATUS STARTING TO INCH NWD ACROSS THE NRN VA PIEDMONT AND SHOULD BE SPREADING TOWARD THE DC AREA EARLY THIS AFTN. CIGS WILL IMPROVE TO MVFR DURING THIS AFTN AS DAYTIME MIXING DEEPENS. LATEST GUIDANCE SHOWS THIS AFTN MAINLY VFR. TEMPORARY/LOCAL RESTRICTIONS POSSIBLE THOUGH IN HEAVIER SHRA AND TSRA. TSRA THIS AFTN MAINLY ISO TO SCT. LOW CLOUDS WILL TRY TO REDEVELOP AGAIN LATE TNGT...BUT LLVL FLOW VEERS FROM THE SW SO SLIGHTLY DRIER AIR MAY LIMIT THIS POTENTIAL. MOIST SLY RETURN FLOW WILL BE ACCOMPANIED BY DAILY CHANCES FOR SHRA AND TSRA DURING THE REST OF THE WEEK...WITH THE GREATEST CHANCES ON THURSDAY. THE POTENTIAL IS THERE FOR PERIODS OF LOW CLOUDS AND FOG EACH NGT/ERY MRNG GIVEN THE MOIST BOUNDARY LAYER IN PLACE. A COLD FRONT MOVES INTO THE REGION ON SATURDAY AND STALLS WITH CONTINUED ISOLATED TO SCT TSTMS INTO EARLY NEXT WEEK. && .MARINE... SLY CHANNELING WILL STRENGTHEN DURING THE AFTN HRS OVER THE BAY. SCA IN EFFECT FOR MOST OF THE MD CHSPK BAY. SMALL CRAFT ADVISORIES ARE POSSIBLE AGAIN THURSDAY NIGHT...MAINLY ON THE CENTRAL BAY AND LOWER TIDAL POTOMAC. VERY LOW WIND SPEEDS ARE EXPECTED EARLY NEXT WEEK AS THE FRONT STALLS OVER OR NEAR THE WATERS. && .TIDES/COASTAL FLOODING... AFTER A MORNING OF NEARLY 1.5FT POSITIVE TIDAL ANOMALIES... SOMEWHAT OF A DECREASE TOWARD THE AFTN H.T. CYCLES. ANOMALIES AROUND CLOSER TO ONE FT...WHICH MAY HOLD STEADY INTO THE OVERNIGHT HRS. WILL MONITOR THE LATEST TRENDS AND THE OVERNIGHT SLY CHANNELING WIND CONTRIBUTION FOR ADZY POTENTIAL. SLY FLOW AND NEAR NEW MOON LUNAR CYCLE WILL CONTINUE THROUGH THE END OF THE WEEK AS HIGH PRESSURE REMAINS OFF THE EAST COAST. THE HIGHER OF THE TWO HIGH TIDES EACH DAY WILL BE THE ONE TO WATCH FOR POTENTIAL MINOR TIDAL FLOODING. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ531>533- 539>542. SMALL CRAFT ADVISORY FROM 11 AM TO 6 PM EDT THURSDAY FOR ANZ530>534-537>543. SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ534-537- 543. && $$ UPDATE...GMS PREV DISCUSSION...JRK/CAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
609 PM EDT WED AUG 7 2013 .SYNOPSIS... SOUTHERLY WINDS BETWEEN HIGH PRESSURE OFF THE EAST COAST AND A COLD FRONT APPROACHING FROM THE MIDWEST WILL KEEP WARM AND MORE HUMID CONDITIONS TO OUR AREA TONIGHT...ALONG WITH A CHANCE FOR A FEW SHOWERS AND THUNDERSTORMS. SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD LATER TONIGHT AND THURSDAY MORNING AS THE FRONT MOVES ACROSS WESTERN AND CENTRAL NEW YORK. SOMEWHAT UNSETTLED WEATHER WILL LAST INTO FRIDAY. && .NEAR TERM /THROUGH THURSDAY/... ONGOING CONVECTION WILL MAKE THIS EVENINGS FORECAST A FAST EVOLVING ONE...AS SEVERAL AREAS OF THUNDERSTORMS CAN BE SEEN ON RADAR LATE THIS AFTERNOON. THE MOST SIGNIFICANT CLUSTER IS TO OUR SOUTH...WITH A SCATTERED LINE EXTENDING FROM ROCHESTER TO THE SAINT LAWRENCE...AND ANOTHER LINE EXTENDING FROM SE MICHIGAN INTO SOUTHERN ONTARIO NORTH OF LAKE ONTARIO. THE MAJORITY OF THIS ACTIVITY IS NOT ACROSS WESTERN NEW YORK...DESPITE FAIRLY UNSTABLE AIR IN PLACE OF AROUND 1000 J/KG. BASED ON RADAR TRENDS AND THE SCATTERED ACTIVITY ACROSS WESTERN MICHIGAN...AND CLEARING UPSTREAM ON VISIBLE SATELLITE...EXPECT ONLY SCATTERED CONVECTION DURING THE EVENING HOURS. THIS IS SUPPORTED BY THE 18Z NAM AND MOST HRRR RUNS...AND WHILE SOME OTHER GUIDANCE CARRIES SIGNIFICANT QPF THIS EVENING...MUCH OF THIS IS ADVECTING AREAS OF CONVECTION WHICH HAVE NOT DEVELOPED AS FORECAST. LATER TONIGHT MAY BE A DIFFERENT STORY...AS THE SHOWERS AND THUNDERSTORMS ACROSS ONTARIO ARE FORECASTS TO DROP ACROSS OUR REGION AS THE FRONTAL BOUNDARY SAGS SOUTH. THIS WILL LIKELY BRING SHOWERS AND THUNDERSTORMS TO MOST LOCATIONS TONIGHT...MAINLY IN THE 11 PM TO 4 AM TIMEFRAME. GIVEN WIND FIELDS AND LINGERING INSTABILITY...THERE WOULD BE A MARGINAL OPPORTUNITY FOR SEVERE WEATHER WITH THIS...BUT PROBABLY CONTINGENT ON STRONG STORMS DEVELOPING UPSTREAM AND ADVECTING INTO OUR REGION. THIS SCENARIO WOULD GIVE US OPPORTUNITY TO ADJUST...AND GIVEN THE MARGINAL PROBABILITY WILL NOT CARRY ANY ENHANCED WORDING AT THIS TIME. WITH THE CONTINUED INFLUX OF WARM AND HUMID AIR THROUGH THE NIGHT...THE OVERNIGHT LOWS WILL BE IN THE MIDDLE TO UPPER 60S AND EVEN NEAR 70 IN DOWNSLOPING AREAS ACROSS THE LAKE PLAINS AND IN URBAN AREAS. WITH THE SLOW PASSAGE OF THE COL FRONT ON THURSDAY...EXPECT HIGH TEMPS TO REACH THE UPPER 70S TO LOWER 80S. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... MATURE SURFACE LOW PRESSURE AND PARENT UPPER LEVEL LOW WILL BE CENTERED OVER NORTHERN ONTARIO PROVINCE NEAR THE HUDSON BAY THURSDAY EVENING. A COLD FRONT ORIENTED FROM A TRIPLE POINT LOW OVER THE CANADIAN MARITIMES SOUTHWEST ACROSS THE ADIRONDACKS TO THE OHIO VALLEY WILL BE STALLING/SLOWING AS IT BECOMES PARALLEL WITH THE UPPER LEVEL FLOW. A SURFACE WAVE WILL LIFT NORTHEAST ALONG THE FRONT THURSDAY EVENING. A SWATH OF SHOWERS ASSOCIATED WITH THIS WAVE AND POSSIBLY SOME EMBEDDED LIGHTING LOOKS TO SHIFT ACROSS THE SOUTHERN TIER INTO THE FINGER LAKES AND ACROSS CENTRAL NEW YORK IN THE EVENING. ITS NORTHERN EDGE MAY EVEN BRING SOME LIGHT RAIN TO THE NIAGARA FRONTIER. THE SHOWERS WILL SHIFT EAST INTO CENTRAL AND EASTERN NEW YORK OVERNIGHT. THE SURFACE WAVE WILL SHIFT NORTH ACROSS NEW ENGLAND THROUGH FRIDAY WHILE ACTING TO SHOVE THE COLD FRONT WELL SOUTH AND EAST OF THE FORECAST AREA. A CHANCE OF RAIN WILL LINGER ACROSS THE FINGER LAKES AND NORTH COUNTY FRIDAY MORNING OTHERWISE EXPECT WESTERN AND NORTH CENTRAL NEW YORK TO BE RAIN FREE BY MID-AFTERNOON BEHIND THE FRONT. THE 12Z NAM IS THE ONLY OUTLIER IN THIS SCENARIO AS IT FORECASTS A SECOND SURFACE WAVE TO LIFT ALONG THE FRONT EARLY FRIDAY WITH ANOTHER ROUND OF RAIN ACROSS WNY THROUGH THE AFTERNOON. THIS IDEA HAS BEEN DISCOUNTED WITH THE MAJORITY OF FORECAST MODELS SHOWING DRY CONDITIONS ON FRIDAY. CANADIAN PRAIRIE SOURCED HIGH PRESSURE WILL BUILD ACROSS THE GREAT LAKES REGION THROUGH FRIDAY AND INTO SATURDAY WITH SEASONABLY COOL TEMPERATURES AND DRY SUNNY CONDITIONS TO START OFF THE WEEKEND. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AN AMPLIFIED WESTERN RIDGE AND EASTERN TROUGH 500MB PATTERN WILL BE IN PLACE ACROSS SOUTHERN CANADA OVER THE WEEKEND. ZONAL FLOW IN THE BASE OF THE EASTERN CANADIAN TROUGH WILL EXTENDING FROM THE NORTHERN PLAINS EAST ACROSS THE GREAT LAKES TO THE NORTHEAST STATES. THIS SHOULD KEEP SEASONABLY COOL AND DRY WEATHER IN PLACE FOR AT LEAST SUNDAY AND MONDAY. MEDIUM RANGE MODELS THEN SHOW THE NEXT STRONG VORTICITY MAX/DISTURBANCE TO DROP INTO THE BASE OF THIS TROUGH ACROSS THE GREAT LAKES MONDAY NIGHT AND LIFTING INTO ATLANTIC CANADA ON TUESDAY. THE 00Z ECMWF IS MUCH DRIER AHEAD OF THE TROUGH AXIS THAN THE 12Z GFS SHOWING JUST A LIMITED SHOWER THREAT. THE GFS SHOWS MORE OF A FRONTAL ORIENTATION. HAVE ONLY INCLUDED A SLIGHT CHANCE OF SHOWERS FOR NOW MONDAY NIGHT IN TO TUESDAY UNTIL MORE MODEL AGREEMENT CAN BE MADE. BY WEDNESDAY HIGH PRESSURE EITHER LINGERS OR BUILDS BACK ACROSS NEW YORK DEPEND ON WHICH MODEL YOU LOOK AT BUT WILL KEEP WEDNESDAY DRY. THE LINGERING TROUGH OVER EASTERN CANADA WILL KEEP SEASONABLY COOL TEMPERATURES IN PLACE ACROSS THE FORECAST AREA THROUGH MID NEXT WEEK WITH NO STRONG CONNECTION TO THE GULF OR ATLANTIC. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... AT 21Z...MOSTLY VFR CONDITIONS WERE IN PLACE...WITH THE MAIN CONCERN THE POTENTIAL FOR CONVECTION. FOR THIS EVENING...THE BEST CHANCE FOR THUNDERSTORMS WILL BE ROC EASTWARD. AFTER THIS... EXPECT A WEAKENING LINE OF THUNDERSTORMS TO DROP ACROSS THE REGION. THUNDERSTORMS COULD TEMPORARILY DROP VSBY TO 2 SM IN HEAVY RAIN. OUTSIDE OF THUNDERSTORMS...EXPECT MAINLY VFR CONDITIONS. LINGERING LOW MOISTURE MAY RESULT IN SOME LOW CLOUDS OR FOG AT JHW...OR BRIEF PERIODS OF MVFR CIGS ELSEWHERE. TAFS HEDGE ON THE OPTIMISTIC SIDE...SINCE THERE IS STILL UNCERTAINTY AS TO WHERE RAIN WILL FALL OVERNIGHT. OUTLOOK... THURSDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. SATURDAY AND SUNDAY...VFR. MONDAY...VFR WITH CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS. && .MARINE... AS A COLD FRONT CROSSES THE CENTRAL LAKES LATE TONIGHT AND EASTERN LAKES ON THURSDAY...THE WINDS WILL SWITCH TO THE WEST SOUTHWEST AND DIMINISH. HIGH PRESSURE IS FORECAST TO SETTLE ACROSS THE EASTERN LAKES ON FRIDAY. SMALL CRAFT ADVISORY CONDITIONS ARE NOT EXPECTED. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...WCH NEAR TERM...APFFEL/WCH SHORT TERM...SMITH LONG TERM...SMITH AVIATION...APFFEL/WCH MARINE...WCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
603 PM EDT WED AUG 7 2013 .SYNOPSIS... RAIN AND THUNDER CHANCES INCREASE THIS EVENING, AS A COLD FRONT MOVES SOUTHEAST TOWARDS THE AREA. THIS FEATURE WILL THEN STALL WEST OF THE AREA BY MORNING, KEEPING THE THREAT FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE WORK WEEK. THIS FRONTAL PASSAGE LOOKS TO FINALLY OCCUR FRIDAY EVENING. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 545 PM UPDATE... WITH CLOUDY SKIES AND MARINE LAYER SHOWERS ARE NOT MATERIALIZING. LOWERED POPS. A FEW SHOWERS AND TSTORMS FORMED IN WRN NY AND WRN PA BUT THEY ARE DYING AS THEY MOVE EAST. BULK OF PA PRECIP WILL MISS TO THE SOUTH AND VERY LITTLE IN NY. SEE NO REASON WHY THE MARINE LAYER WITH COOL TEMPS WILL NOT REMAIN THROUGH THE NIGHT. 245 PM UPDATE... SFC LOPRES JUST SOUTH OF HUDSON BAY HAS DRAPED A CDFNT DOWN ACRS LK HURON AND SWWRD INTO NRN MO. AT THE SAME TIME CONVECTION THAT DVLPD OVRNGT HAS THROWN OUT A GUST FRONT AND HAS ALLOWED STORMS TO DVLP ACRS NRN OH. MAIN AREA OF STORMS ACRS SRN ONTARIO HAS LIFTED NORTH AS EXPECTED WITH MAIN S/WV ROTATING ARND BASE OF HUDSON BAY TROF. TIMING ON THIS AFOREMENTIONED LINE OF STORMS PLACES IT INTO EXTRM WRN ZONES BY 21Z THIS AFTN AND WL WORK TWD CNTRL PART OF CWA BY 00Z. THIS LOOKS TO BE KICKED OFF BY S/WV WORKING ITS WAY EAST ACRS NRN OH AND IT APPEARS TO BE HEADING A LITTLE SOUTH OF EAST. THUS, WL MAINTAIN LKLY POPS THRU TONIGHT WITH CONTINUAL MOISTURE BEING PUMPED INTO REGION ON LLJ AND PW VALUES INCRSG TO NEAR 1.50 INCHES AND ANY SUBTLE S/WVS THAT ENCROACH UPON THE AREA. BULLSEYE OF QPF ALONG THE I-81 CORRIDOR ADVERTISED BY 12Z GFS AND LATEST RAP APPEARS TO BE A RESULT OF CONVECTIVE FEEDBACK AND HV DISCOUNTED THIS SOLN. THINK THAT AREAL AVGS WL LKLY BE BETWEEN 0.25 AND 0.50 INCHES. AS FOR OVRNGT MINS DO NOT THINK TEMPS WL MV MUCH AS CLDS RMN ENTRENCHED OVR AREA. FCST LOWS WL BOTTOM OUT IN THE L/M 60S. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... 245 PM UPDATE... FRONTAL BNDRY WL STALL OUT THUR MRNG JUST TO THE WEST OF THE AREA AND RMN THERE INTO FRIDAY. VRY LITTLE MIXING WL OCCUR DRG THE DAY AS AREA WL LKLY BE SOCKED IN WITH CLDS ONCE AGAIN. MAX TEMPS WL JUST BARELY TOP OUT IN THE 80S. CAPES WL BE SIMILAR TO WED WITH VALUES APPCHG 1000 J/KG BUT WIND SHEAR IS EXPECTED TO DROP OFF DRG THE DAY. PW VALUES PROGGED TO APPCH 2.00 INCHES DRG THE DAY THUS ANY STORM THAT DVLPS MAY PRODUCE MODERATE TO HVY RAIN. LKLY POPS WL CONTINUE TOMORROW NGT AS BNDRY RMNS STALLED OUT TO THE WEST. MED RANGE MODELS HINTING AT SFC LOPRES RIDING UP ALONG THE FRONT THU NGT AND HELPING GIVE THE FRONT A LITTLE SHOVE TO THE SOUTH. FROPA NOW LOOKS TO OCCUR DRG THE DAY FRIDAY. THUS, HV TAKEN OUT PCPN AFT 12Z SATURDAY. NO OTHER CHGS NEEDED TO THE END OF THE SHORT TERM WITH PERHAPS SOME LINGERING SHOWERS ON FRIDAY WITH RMNG UL WV MVG THRU BHND FRONT. ELONGATED VORT MAX PROGGED TO MV THRU ON SATURDAY BUT WITH DRY AIRMASS IN PLACE NOT EXPECTING MUCH MORE THAN CLDS AT THIS POINT. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... 200 PM UPDATE... AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S. A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST. FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE AFTERNOON MONDAY. UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... UPDATED AT 200 PM...GENERALLY MVFR CIGS ACROSS THE AREA. PATCH OF SHOWERS MOVING ACROSS NORTHEAST PA INTO THE CATSKILLS WITH IFR CIGS OVER HIGHER TERRAIN. A LINE OF SCATTERED SHOWERS AND THUNDERSTORMS IS EXPECTED TO MOVE ACROSS WESTERN NEW YORK INTO THE FINGER LAKES REGION BETWEEN 21Z AND 00Z AND CONTINUE EAST EXITING THE AREA BETWEEN 03Z AND 05Z. OVERNIGHT MVFR CIGS ARE EXPECTED TO CONTINUE WITH IFR ACROSS THE HIGHER TERRAIN. THERE IS A CHANCE OF SHOWERS MOVING AFTER 06Z AND SOME MVFR VSBYS IN LIGHT FOG. WINDS WILL BE S TO SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15 KTS TONIGHT. OUTLOOK... THU AND THU NGT...MVFR IN SHRA AND TSRA. FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH. SAT THRU MON...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN/TAC NEAR TERM...PVN/TAC SHORT TERM...PVN LONG TERM...BMW AVIATION...BMW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
249 PM EDT WED AUG 7 2013 .SYNOPSIS... RAIN AND THUNDER CHANCES INCREASE LATE THIS AFTERNOON AS A LONG AWAITED COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL THEN STALL WEST OF THE AREA BY MORNING KEEPING THE THREAT FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE WORK WEEK. THIS FRONTAL PASSAGE LOOKS TO FINALLY OCCUR SOMETIME FRIDAY EVENING. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 245 PM UPDATE... SFC LOPRES JUST SOUTH OF HUDSON BAY HAS DRAPED A CDFNT DOWN ACRS LK HURON AND SWWRD INTO NRN MO. AT THE SAME TIME CONVECTION THAT DVLPD OVRNGT HAS THROWN OUT A GUST FRONT AND HAS ALLOWED STORMS TO DVLP ACRS NRN OH. MAIN AREA OF STORMS ACRS SRN ONTARIO HAS LIFTED NORTH AS EXPECTED WITH MAIN S/WV ROTATING ARND BASE OF HUDSON BAY TROF. TIMING ON THIS AFOREMENTIONED LINE OF STORMS PLACES IT INTO EXTRM WRN ZONES BY 21Z THIS AFTN AND WL WORK TWD CNTRL PART OF CWA BY 00Z. THIS LOOKS TO BE KICKED OFF BY S/WV WORKING ITS WAY EAST ACRS NRN OH AND IT APPEARS TO BE HEADING A LITTLE SOUTH OF EAST. THUS, WL MAINTAIN LKLY POPS THRU TONIGHT WITH CONTINUAL MOISTURE BEING PUMPED INTO REGION ON LLJ AND PW VALUES INCRSG TO NEAR 1.50 INCHES AND ANY SUBTLE S/WVS THAT ENCROACH UPON THE AREA. BULLSEYE OF QPF ALONG THE I-81 CORRIDOR ADVERTISED BY 12Z GFS AND LATEST RAP APPEARS TO BE A RESULT OF CONVECTIVE FEEDBACK AND HV DISCOUNTED THIS SOLN. THINK THAT AREAL AVGS WL LKLY BE BETWEEN 0.25 AND 0.50 INCHES. AS FOR OVRNGT MINS DO NOT THINK TEMPS WL MV MUCH AS CLDS RMN ENTRENCHED OVR AREA. FCST LOWS WL BOTTOM OUT IN THE L/M 60S. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... 245 PM UPDATE... FRONTAL BNDRY WL STALL OUT THUR MRNG JUST TO THE WEST OF THE AREA AND RMN THERE INTO FRIDAY. VRY LITTLE MIXING WL OCCUR DRG THE DAY AS AREA WL LKLY BE SOCKED IN WITH CLDS ONCE AGAIN. MAX TEMPS WL JUST BARELY TOP OUT IN THE 80S. CAPES WL BE SIMILAR TO WED WITH VALUES APPCHG 1000 J/KG BUT WIND SHEAR IS EXPECTED TO DROP OFF DRG THE DAY. PW VALUES PROGGED TO APPCH 2.00 INCHES DRG THE DAY THUS ANY STORM THAT DVLPS MAY PRODUCE MODERATE TO HVY RAIN. LKLY POPS WL CONTINUE TOMORROW NGT AS BNDRY RMNS STALLED OUT TO THE WEST. MED RANGE MODELS HINTING AT SFC LOPRES RIDING UP ALONG THE FRONT THU NGT AND HELPING GIVE THE FRONT A LITTLE SHOVE TO THE SOUTH. FROPA NOW LOOKS TO OCCUR DRG THE DAY FRIDAY. THUS, HV TAKEN OUT PCPN AFT 12Z SATURDAY. NO OTHER CHGS NEEDED TO THE END OF THE SHORT TERM WITH PERHAPS SOME LINGERING SHOWERS ON FRIDAY WITH RMNG UL WV MVG THRU BHND FRONT. ELONGATED VORT MAX PROGGED TO MV THRU ON SATURDAY BUT WITH DRY AIRMASS IN PLACE NOT EXPECTING MUCH MORE THAN CLDS AT THIS POINT. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... 200 PM UPDATE... AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S. A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST. FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE AFTERNOON MONDAY. UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... UPDATED AT 200 PM...GENERALLY MVFR CIGS ACROSS THE AREA. PATCH OF SHOWERS MOVING ACROSS NORTHEAST PA INTO THE CATSKILLS WITH IFR CIGS OVER HIGHER TERRAIN. A LINE OF SCATTERED SHOWERS AND THUNDERSTORMS IS EXPECTED TO MOVE ACROSS WESTERN NEW YORK INTO THE FINGER LAKES REGION BETWEEN 21Z AND 00Z AND CONTINUE EAST EXITING THE AREA BETWEEN 03Z AND 05Z. OVERNIGHT MVFR CIGS ARE EXPECTED TO CONTINUE WITH IFR ACROSS THE HIGHER TERRAIN. THERE IS A CHANCE OF SHOWERS MOVING AFTER 06Z AND SOME MVFR VSBYS IN LIGHT FOG. WINDS WILL BE S TO SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15 KTS TONIGHT. OUTLOOK... THU AND THU NGT...MVFR IN SHRA AND TSRA. FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH. SAT THRU MON...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN SHORT TERM...PVN LONG TERM...BMW AVIATION...BMW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
157 PM EDT WED AUG 7 2013 .SYNOPSIS... A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VALLEY WILL LEAD TO SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER MAINLY ALONG AND WEST OF THE INTERSTATE 81 CORRIDOR BY THIS AFTERNOON. RAIN AND THUNDER CHANCES WILL INCREASE AREAWIDE BEGINNING TONIGHT AS A LONG AWAITED COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL THEN STALL ACROSS THE AREA BY THURSDAY MORNING KEEPING THE THREAT FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1 PM UPDATE...ANOTHER GRID UPDATE TO LOWER MAX TEMPS AS CLDS ARE HANGING TUFF ACRS CWA THIS AFTN. THIN CLDS ARE AS CLOSE AS OUR WRN BORDER BUT EXPECT CLDS WL NOT BREAK UP WITH SRLY FLOW CONTG TO PUMP MOISTURE INTO CNTRL NY. THUS, HV GONE CLDY AREAWIDE FOR TDA WITH HIGHS IN SOME LOCALES STRUGGLING TO REACH 70F. NOT OVERLY IMPRESSED WITH SVR CONVECTIVE CHCS THIS AFTN AS WRN NY APPEARS TO HV THE BEST INSTABILITY, HWVR WL HV TO WATCH ANY STORMS THAT ARE ABLE TO MV INTO THE REGION AS LOW-LVL WIND SHEAR IS CERTAINLY SUBSTANTIAL. TIMING ON CONVECTIVE LINE ACRS ONTARIO AND NWPA PUTS IT INTO EXTRM WRN ZONES BY 21Z. 1045 AM UPDATE... CONVECTION IS BEGINNING TO DVLP ON GUST FRONT OVR NRN OHIO AT THIS TIME. MCS NOW OVR SRN ONTARIO/MICHIGAN HAS DVLPD AHD OF MAIN UPR WV AND THIS SHUD BEGIN TO FIZZLE THRU THE DAY. SHUD ALSO HEAD OFF JUST TO THE NORTH OF CWA PER LATEST HIRES MODELS IN 1000-500MB THICKNESS FIELDS. MAIN QUESTION IS WHAT KIND OF REMNANT WV THIS MCS CAN DISLODGE TWD THE FA THIS AFTN. EML PRESENT ON 12Z ILN SOUNDING EXPECTED TO SPREAD INTO WRN ZONES THIS AFTN. IF ANYTHING CAN DVLP THIS AFTN WHICH LATEST MODELS ARE HOLDING QPF OFF UNTIL AFT 00Z, WITH EXCEPTION OF HRRR AND RAP, POTENTIAL EXISTS FOR ISOLD SVR. CAPES FCST TO BE ON THE ORDER OF 1000 J/KG AND BULK SHEAR VALUES OF 20-30KTS IN THE 0-1 AND 0-3KM LAYERS WITH QUITE A BIT OF DIRECTIONAL SHEAR PRESENT PER KELM RAP SNDGS. SEE NO REASON TO CHG POP FCST AT THIS TIME WITH SCTD SHOWERS AND ISOLD THUNDER ACRS WRN ZONES AFT 18Z AND THEN INCRSG TO SCTD THUNDER LATE THIS AFTN. WL CONTINUE TO MONITOR FOR ANY CHGS TO CURRENT THINKING. ALSO RMVD MENTION OF ISOLD SHOWERS ACRS SRN ZONES IN MARINE LYR FOR THE NEXT COUPLE OF HOURS. WITH EXTENSIVE CLD CVR ACRS THE REGION AND TEMPS ONLY RISING 1-2 DEGREES OVR THE PAST HR HV LEFT MAX TEMP FCST UNCHANGED. MAX TEMPS SHUD RISE TO FCST VALUES IF BREAKS CAN DVLP IN CLDS. FOR NOW, WILL JUST SIT AND WAIT BFR MAKING ANY CHGS TO TEMP/POP/WX GRIDS. 625 AM UPDATE... TOOK THE LIBERTY OF INCREASING HIGH TEMPS A DEGREE OR TWO FOR LATER TODAY AS LOW STRATUS UP HERE AT THE AIRPORT LOOKS PRETTY THIN. AS A RESULT...A LITTLE MORE SUNSHINE IS EXPECTED WHICH SHOULD HELP IN THE DIURNAL HEATING DEPARTMENT. NO OTHER CHANGES NEEDED AT THE PRESENT TIME. PREVIOUS NEAR TERM DISCUSSION... EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING LOW STRATUS CONTINUING TO WORK NORTH INTO THE FCST AREA AS SOUTHERLY RETURN FLOW INCREASES ON THE BACKSIDE OF HIGH PRESSURE NOW POSITIONED OF THE MID-ATLANTIC COAST. THE PRESENCE OF THESE CLOUDS MAKES TODAY/S FORECAST ANYTHING BUT EASY AS CLOUD COVER WILL HAVE SIGNIFICANT IMPACTS ON BOTH THE DESTABILIZATION POTENTIAL AND HIGH TEMP FORECASTS LATER TODAY. IN ANY EVENT ...UPPER-LEVEL PATTERN REMAINS DOMINATED BY A BROAD UPPER LOW WHICH CONTINUES TO SPIN JUST SOUTH OF HUDSON BAY THIS MORNING...WITH DEVELOPING DIFFLUENT FLOW DOWNSTREAM ACROSS THE CENTRAL AND EASTERN GREAT LAKES. EMBEDDED WITHIN THIS FLOW IS A FAIRLY DECENT SHORTWAVE AND VERY DISCERNIBLE MCS WHICH CONTINUES TO WORK THROUGH WESTERN/CENTRAL MICHIGAN THIS MORNING. IN FACT...RADAR APPEARANCE OF THIS MCS IS VERY IMPRESSIVE WITH ALL INDICATIONS SUGGESTING THIS FEATURE HAS ORGANIZED INTO A WELL- DEFINED DERECHO WITH WIDESPREAD WIND DAMAGE REPORTED AS FAR WEST AS SOUTHEASTERN NORTH DAKOTA. CURRENT THINKING IS THIS FEATURE WILL WEAKEN WITH FURTHER EASTWARD PROGRESS INTO SOUTHERN ONTARIO AS ATMOSPHERE DOWNSTREAM REMAINS MUCH MORE STABLE. LINGERING MCV/SHORTWAVE ENERGY LIKELY TO PASS JUST TO OUR NORTH LATER THIS MORNING AS FLOW UPPER FLOW BECOMES MORE SOUTHWEST DOWNSTREAM OVER THE EASTERN LAKES. MOVING INTO TODAY...FCST MODELS CONTINUE TO HINT AT DEVELOPING SHWRS/ISO STORMS AS DIURNAL HEATING COMBINES WITH THE PASSING OF A FEW WEAK SHORTWAVES. THAT SAID...MODEL INSTABILITY REMAINS ANYTHING BUT IMPRESSIVE WITH BOTH GFS AND NAM SUGGESTING MLCAPE VALUES OF MAYBE A FEW HUNDRED JOULES AT BEST...MAINLY ALONG AND WEST OF THE I-81 CORRIDOR. CONSIDERING FORCING REMAINS FAIRLY WEAK DESPITE WHAT APPEARS TO BE A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VLY...AREAL COVERAGE OF SHWRS/STORMS LIKELY TO REMAIN IN THE ISO-SCT CATEGORY. FOR NOW HAVE MAINTAINED THIS TREND FROM PREVIOUS FORECASTS WITH THUNDER MENTION MAINLY CONFINED TO AREAS OUTLINED ABOVE. TEMP FORECAST ANYTHING BUT EASY DUE TO LOW STRATUS WHICH SOME MODELS SUGGEST WILL BE WITH US FOR A GOOD PORTION OF THE HEATING CYCLE. WITH THIS BEING THE CASE...HAVE KEPT HIGHEST VALUES (UPPER 70S) CONFINED TO THE IMMEDIATE LAKE PLAIN...WITH COOLER VALUES FROM THE FINGER LAKES AND POINTS SOUTH. OBVIOUSLY A FEW BREAKS HERE AND THERE MAY YIELD WARMER VALUES THAN CURRENTLY FORECAST...ESPECIALLY FOR TWIN TIERS AND FINGER LAKES AREAS. BY TONIGHT...COLD FRONT EXPECTED TO DROP SOUTH ACROSS THE FCST AREA AFTER 00Z THIS EVENING. AS THIS OCCURS...EXPECT SHWRS/STORMS TO INCREASE WITH TIME AND THUS HAVE MAINTAINED NUMEROUS MENTION FOR THE REGION DURING THE ENTIRE PERIOD. OVERNIGHT LOWS SHOULD BE FAIRLY WARM WITH CLOUDS/PRECIP IN THE VICINITY WITH VALUES LARGELY FALLING INTO THE LOWER TO MIDDLE 60S AREAWIDE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AFOREMENTIONED FRONT TO STALL ACROSS THE FCST AREA ON THURSDAY WITH CONTINUES CHANCES FOR SHWRS/STORMS THROUGH MUCH OF THE DAYLIGHT HRS. FCST MODELS TO HINT AT BETTER INSTABILITY GENERATION DURING THE DAY WITH BOTH GFS AND NAM OFFERING ROUGHLY 500-1000 J/KG. THIS COMBINED WITH 0-6 KM BULK SHEAR VECTORS OF 30-40 KTS SUGGESTS THAT SOME SEVERE WILL BE POSSIBLE IF STORMS BECOME ORGANIZED. CURRENT SPC DAY 2 OUTLOOK HIGHLIGHTS OUR AREA WITH A "SEE TEXT" FOR THE POSSIBILITY OF ORGANIZED MULTICELLS OFFERING AN ISOLATED WIND/HAIL THREAT. AS HAS BEEN THE CASE IN RECENT DAYS...OVERALL SYNOPTIC FORCING LOOKS FAIRLY WEAK DESPITE FRONTAL BOUNDARY REMAINING POSITIONED OVER THE AREA. BEYOND THIS...SHWRS/STORMS REMAIN IN THE FCST THROUGH FRI WITH INDICATIONS SUGGESTING BEST FORCING WILL ARRIVE FRI NGT/EARLY SAT AS HUDSON BAY UPPER LOW BEGINS TO SHIFT EAST AND TAKE ON A NEGATIVE TILT WITH TIME. AS THIS OCCURS...MODELS SHOW A SFC LOW LIFTING NORTH FROM THE OHIO VLY WITH A PRETTY GOOD SLUG OF MOISTURE AS PWAT VALUES EXCEED 2" BY 00Z SAT. SOME AREAS MAY SEE A BRIEF PERIOD OF MODERATE TO HEAVY RAIN FRI NGT/EARLY SAT BUT MAIN AREA SHOULD MOVE FAIRLY QUICKLY TO THE NORTHEAST...THUS NO SIGNIFICANT IMPACTS EXPECTED. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... 200 PM UPDATE... AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S. A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST. FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE AFTERNOON MONDAY. UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... UPDATED AT 200 PM...GENERALLY MVFR CIGS ACROSS THE AREA. PATCH OF SHOWERS MOVING ACROSS NORTHEAST PA INTO THE CATSKILLS WITH IFR CIGS OVER HIGHER TERRAIN. A LINE OF SCATTERED SHOWERS AND THUNDERSTORMS IS EXPECTED TO MOVE ACROSS WESTERN NEW YORK INTO THE FINGER LAKES REGION BETWEEN 21Z AND 00Z AND CONTINUE EAST EXITING THE AREA BETWEEN 03Z AND 05Z. OVERNIGHT MVFR CIGS ARE EXPECTED TO CONTINUE WITH IFR ACROSS THE HIGHER TERRAIN. THERE IS A CHANCE OF SHOWERS MOVING AFTER 06Z AND SOME MVFR VSBYS IN LIGHT FOG. WINDS WILL BE S TO SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15 KTS TONIGHT. OUTLOOK... THU AND THU NGT...MVFR IN SHRA AND TSRA. FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH. SAT THRU MON...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...CMG/PVN NEAR TERM...CMG/PVN SHORT TERM...CMG LONG TERM...BMW AVIATION...BMW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
107 PM EDT WED AUG 7 2013 .SYNOPSIS... A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VALLEY WILL LEAD TO SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER MAINLY ALONG AND WEST OF THE INTERSTATE 81 CORRIDOR BY THIS AFTERNOON. RAIN AND THUNDER CHANCES WILL INCREASE AREAWIDE BEGINNING TONIGHT AS A LONG AWAITED COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL THEN STALL ACROSS THE AREA BY THURSDAY MORNING KEEPING THE THREAT FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1 PM UPDATE...ANOTHER GRID UPDATE TO LOWER MAX TEMPS AS CLDS ARE HANGING TUFF ACRS CWA THIS AFTN. THIN CLDS ARE AS CLOSE AS OUR WRN BORDER BUT EXPECT CLDS WL NOT BREAK UP WITH SRLY FLOW CONTG TO PUMP MOISTURE INTO CNTRL NY. THUS, HV GONE CLDY AREAWIDE FOR TDA WITH HIGHS IN SOME LOCALES STRUGGLING TO REACH 70F. NOT OVERLY IMPRESSED WITH SVR CONVECTIVE CHCS THIS AFTN AS WRN NY APPEARS TO HV THE BEST INSTABILITY, HWVR WL HV TO WATCH ANY STORMS THAT ARE ABLE TO MV INTO THE REGION AS LOW-LVL WIND SHEAR IS CERTAINLY SUBSTANTIAL. TIMING ON CONVECTIVE LINE ACRS ONTARIO AND NWPA PUTS IT INTO EXTRM WRN ZONES BY 21Z. 1045 AM UPDATE... CONVECTION IS BEGINNING TO DVLP ON GUST FRONT OVR NRN OHIO AT THIS TIME. MCS NOW OVR SRN ONTARIO/MICHIGAN HAS DVLPD AHD OF MAIN UPR WV AND THIS SHUD BEGIN TO FIZZLE THRU THE DAY. SHUD ALSO HEAD OFF JUST TO THE NORTH OF CWA PER LATEST HIRES MODELS IN 1000-500MB THICKNESS FIELDS. MAIN QUESTION IS WHAT KIND OF REMNANT WV THIS MCS CAN DISLODGE TWD THE FA THIS AFTN. EML PRESENT ON 12Z ILN SOUNDING EXPECTED TO SPREAD INTO WRN ZONES THIS AFTN. IF ANYTHING CAN DVLP THIS AFTN WHICH LATEST MODELS ARE HOLDING QPF OFF UNTIL AFT 00Z, WITH EXCEPTION OF HRRR AND RAP, POTENTIAL EXISTS FOR ISOLD SVR. CAPES FCST TO BE ON THE ORDER OF 1000 J/KG AND BULK SHEAR VALUES OF 20-30KTS IN THE 0-1 AND 0-3KM LAYERS WITH QUITE A BIT OF DIRECTIONAL SHEAR PRESENT PER KELM RAP SNDGS. SEE NO REASON TO CHG POP FCST AT THIS TIME WITH SCTD SHOWERS AND ISOLD THUNDER ACRS WRN ZONES AFT 18Z AND THEN INCRSG TO SCTD THUNDER LATE THIS AFTN. WL CONTINUE TO MONITOR FOR ANY CHGS TO CURRENT THINKING. ALSO RMVD MENTION OF ISOLD SHOWERS ACRS SRN ZONES IN MARINE LYR FOR THE NEXT COUPLE OF HOURS. WITH EXTENSIVE CLD CVR ACRS THE REGION AND TEMPS ONLY RISING 1-2 DEGREES OVR THE PAST HR HV LEFT MAX TEMP FCST UNCHANGED. MAX TEMPS SHUD RISE TO FCST VALUES IF BREAKS CAN DVLP IN CLDS. FOR NOW, WILL JUST SIT AND WAIT BFR MAKING ANY CHGS TO TEMP/POP/WX GRIDS. 625 AM UPDATE... TOOK THE LIBERTY OF INCREASING HIGH TEMPS A DEGREE OR TWO FOR LATER TODAY AS LOW STRATUS UP HERE AT THE AIRPORT LOOKS PRETTY THIN. AS A RESULT...A LITTLE MORE SUNSHINE IS EXPECTED WHICH SHOULD HELP IN THE DIURNAL HEATING DEPARTMENT. NO OTHER CHANGES NEEDED AT THE PRESENT TIME. PREVIOUS NEAR TERM DISCUSSION... EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING LOW STRATUS CONTINUING TO WORK NORTH INTO THE FCST AREA AS SOUTHERLY RETURN FLOW INCREASES ON THE BACKSIDE OF HIGH PRESSURE NOW POSITIONED OF THE MID-ATLANTIC COAST. THE PRESENCE OF THESE CLOUDS MAKES TODAY/S FORECAST ANYTHING BUT EASY AS CLOUD COVER WILL HAVE SIGNIFICANT IMPACTS ON BOTH THE DESTABILIZATION POTENTIAL AND HIGH TEMP FORECASTS LATER TODAY. IN ANY EVENT ...UPPER-LEVEL PATTERN REMAINS DOMINATED BY A BROAD UPPER LOW WHICH CONTINUES TO SPIN JUST SOUTH OF HUDSON BAY THIS MORNING...WITH DEVELOPING DIFFLUENT FLOW DOWNSTREAM ACROSS THE CENTRAL AND EASTERN GREAT LAKES. EMBEDDED WITHIN THIS FLOW IS A FAIRLY DECENT SHORTWAVE AND VERY DISCERNIBLE MCS WHICH CONTINUES TO WORK THROUGH WESTERN/CENTRAL MICHIGAN THIS MORNING. IN FACT...RADAR APPEARANCE OF THIS MCS IS VERY IMPRESSIVE WITH ALL INDICATIONS SUGGESTING THIS FEATURE HAS ORGANIZED INTO A WELL- DEFINED DERECHO WITH WIDESPREAD WIND DAMAGE REPORTED AS FAR WEST AS SOUTHEASTERN NORTH DAKOTA. CURRENT THINKING IS THIS FEATURE WILL WEAKEN WITH FURTHER EASTWARD PROGRESS INTO SOUTHERN ONTARIO AS ATMOSPHERE DOWNSTREAM REMAINS MUCH MORE STABLE. LINGERING MCV/SHORTWAVE ENERGY LIKELY TO PASS JUST TO OUR NORTH LATER THIS MORNING AS FLOW UPPER FLOW BECOMES MORE SOUTHWEST DOWNSTREAM OVER THE EASTERN LAKES. MOVING INTO TODAY...FCST MODELS CONTINUE TO HINT AT DEVELOPING SHWRS/ISO STORMS AS DIURNAL HEATING COMBINES WITH THE PASSING OF A FEW WEAK SHORTWAVES. THAT SAID...MODEL INSTABILITY REMAINS ANYTHING BUT IMPRESSIVE WITH BOTH GFS AND NAM SUGGESTING MLCAPE VALUES OF MAYBE A FEW HUNDRED JOULES AT BEST...MAINLY ALONG AND WEST OF THE I-81 CORRIDOR. CONSIDERING FORCING REMAINS FAIRLY WEAK DESPITE WHAT APPEARS TO BE A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VLY...AREAL COVERAGE OF SHWRS/STORMS LIKELY TO REMAIN IN THE ISO-SCT CATEGORY. FOR NOW HAVE MAINTAINED THIS TREND FROM PREVIOUS FORECASTS WITH THUNDER MENTION MAINLY CONFINED TO AREAS OUTLINED ABOVE. TEMP FORECAST ANYTHING BUT EASY DUE TO LOW STRATUS WHICH SOME MODELS SUGGEST WILL BE WITH US FOR A GOOD PORTION OF THE HEATING CYCLE. WITH THIS BEING THE CASE...HAVE KEPT HIGHEST VALUES (UPPER 70S) CONFINED TO THE IMMEDIATE LAKE PLAIN...WITH COOLER VALUES FROM THE FINGER LAKES AND POINTS SOUTH. OBVIOUSLY A FEW BREAKS HERE AND THERE MAY YIELD WARMER VALUES THAN CURRENTLY FORECAST...ESPECIALLY FOR TWIN TIERS AND FINGER LAKES AREAS. BY TONIGHT...COLD FRONT EXPECTED TO DROP SOUTH ACROSS THE FCST AREA AFTER 00Z THIS EVENING. AS THIS OCCURS...EXPECT SHWRS/STORMS TO INCREASE WITH TIME AND THUS HAVE MAINTAINED NUMEROUS MENTION FOR THE REGION DURING THE ENTIRE PERIOD. OVERNIGHT LOWS SHOULD BE FAIRLY WARM WITH CLOUDS/PRECIP IN THE VICINITY WITH VALUES LARGELY FALLING INTO THE LOWER TO MIDDLE 60S AREAWIDE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AFOREMENTIONED FRONT TO STALL ACROSS THE FCST AREA ON THURSDAY WITH CONTINUES CHANCES FOR SHWRS/STORMS THROUGH MUCH OF THE DAYLIGHT HRS. FCST MODELS TO HINT AT BETTER INSTABILITY GENERATION DURING THE DAY WITH BOTH GFS AND NAM OFFERING ROUGHLY 500-1000 J/KG. THIS COMBINED WITH 0-6 KM BULK SHEAR VECTORS OF 30-40 KTS SUGGESTS THAT SOME SEVERE WILL BE POSSIBLE IF STORMS BECOME ORGANIZED. CURRENT SPC DAY 2 OUTLOOK HIGHLIGHTS OUR AREA WITH A "SEE TEXT" FOR THE POSSIBILITY OF ORGANIZED MULTICELLS OFFERING AN ISOLATED WIND/HAIL THREAT. AS HAS BEEN THE CASE IN RECENT DAYS...OVERALL SYNOPTIC FORCING LOOKS FAIRLY WEAK DESPITE FRONTAL BOUNDARY REMAINING POSITIONED OVER THE AREA. BEYOND THIS...SHWRS/STORMS REMAIN IN THE FCST THROUGH FRI WITH INDICATIONS SUGGESTING BEST FORCING WILL ARRIVE FRI NGT/EARLY SAT AS HUDSON BAY UPPER LOW BEGINS TO SHIFT EAST AND TAKE ON A NEGATIVE TILT WITH TIME. AS THIS OCCURS...MODELS SHOW A SFC LOW LIFTING NORTH FROM THE OHIO VLY WITH A PRETTY GOOD SLUG OF MOISTURE AS PWAT VALUES EXCEED 2" BY 00Z SAT. SOME AREAS MAY SEE A BRIEF PERIOD OF MODERATE TO HEAVY RAIN FRI NGT/EARLY SAT BUT MAIN AREA SHOULD MOVE FAIRLY QUICKLY TO THE NORTHEAST...THUS NO SIGNIFICANT IMPACTS EXPECTED. && .LONG TERM /SATURDAY THROUGH TUESDAY/... 200 PM UPDATE... FRIDAY NIGHT WE WILL BE IN THE PROCESS OF MOVING A COLD FRONT THROUGH OUR AREA. SOME SHOWERS MAY LINGER THROUGH FRIDAY NIGHT...ESPECIALLY ACROSS NEPA. A MARKED PUNCH OF DRIER AIR IN THE MID LEVELS OF THE ATMOSPHERE WILL RACE OUT OF THE GREAT LAKES AND BE WITH US BY 12Z SATURDAY. THIS WILL END ANY SHOWER THREAT AND DRY US OUT FOR SATURDAY. HIGH PRESSURE WILL CONTROL OUR WEATHER SUNDAY INTO EARLY NEXT WEEK WITH A BEAUTIFUL STRETCH OF WEATHER. IT WILL REMAIN BELOW AVERAGE WITH 850 TEMPS IN THE LOWER TEENS SUPPORTING HIGHS IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 40S AND 50S. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/... UPDATED AT 630 AM... PATCHY MVFR CIGS WILL GIVE WAY TO VFR CONDITIONS BY 14Z. VFR CONDITIONS WILL PERSIST THROUGH MOST OF THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON THROUGH THIS EVENING WILL BE ACCOMPANIED BY SCATTERED BRIEF PERIODS OF MVFR CIGS AND VSBYS. WINDS WILL BE LIGHT AND VARIABLE THIS MORNING BECOMING SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15 KTS TONIGHT. OUTLOOK... THU AND THU NGT...MVFR IN SHRA AND TSRA. FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH. SAT AND SUN...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...CMG/PVN NEAR TERM...CMG/PVN SHORT TERM...CMG LONG TERM...HEDEN AVIATION...MSE/TAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
200 PM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE NORTHEAST THEN MOVE OFFSHORE OVER THE NEXT SEVERAL DAYS. AS THE RIDGE LOSES ITS GRIP ACROSS THE REGION THE WINDS WILL BECOME SOUTHERLY ALLOWING THE RETURN OF WARMER AND MORE HUMID AIR INTO THE CAROLINAS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA MONDAY THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 2 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF INTERSTATE 95. THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN WILLIAMSBURG COUNTY. A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS CONTINUE. MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR THE BEACHES AROUND SUNRISE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 2 PM WEDNESDAY...THE ATMOSPHERE WILL BE TRANSITIONING BACK TO A MORE TYPICAL SUMMERTIME PATTERN WITH HIGH PRESSURE SETTING UP OFF THE COAST ALLOWING FOR THE RETURN OF MORE HUMID CONDITIONS. AN H5 SUBTROPICAL RIDGE WILL BECOME PINCHED FROM THE SOUTHEAST U.S. WESTWARD TO THE LOWER MS VALLEY AND TX...WITH A STRONG SHORTWAVE PUSHING ACROSS SOUTHEAST CANADA AND WESTWARD MOVING H5 TROFS OVER THE GULF OF MEXICO. DON/T THINK THE AIR-MASS WILL BECOME STRONGLY CAPPED ACROSS THE FORECAST AREA AND WITH SUFFICIENT INSTABILITY EXPECT WIDELY SCATTERED SHOWERS/TSTMS EACH DAY. THE SEA BREEZE FRONT WILL BE THE PRIMARY LIFTING MECHANISM...MORE-SO IN THE AFTERNOON AND EARLY EVENING. MAX/MIN TEMPS WILL BE AT OR ABOVE CLIMO EACH PERIOD. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 2 PM WEDNESDAY...ELONGATED MID LEVEL RIDGE WILL START TO BREAK DOWN EARLY NEXT WEEK WITH LONGWAVE 5H TROUGH SETTING UP OVER THE EAST COAST BY THE END OF THE PERIOD. THE PERIOD WILL START OFF WARM AND RELATIVELY DRY...HIGHS IN THE LOW TO MID 90S AND LOWS IN THE LOW TO MID 70S WITH SLIGHT CHC TO LOW CHC POP. CONVECTION IS LIKELY TO BE DIURNAL IN NATURE AND ASSOCIATED WITH THE SEA BREEZE AND PIEDMONT TROUGH. BREAK DOWN OF THE RIDGE AND RETREATING BERMUDA HIGH ALLOWS A COLD FRONT TO DROP IN FROM THE NORTHWEST ON MON. MID LEVEL TROUGH AXIS NEVER MOVES OFF THE COAST AND THE FRONT ENDS UP LAYING PARALLEL TO THE STEERING FLOW. THIS WILL KEEP THE FRONT STALLED IN THE AREA THROUGH WED. ABUNDANT DEEP MOISTURE IN THE PRESENCE OF THE BOUNDARY...ALONG WITH OCCASIONAL SHORTWAVES PASSING OVERHEAD IN SOUTHEAST FLOW WILL ELEVATE POP CHANCES FOR SECOND HALF OF THE PERIOD. WILL KEEP POP IN CHC CAT BUT INCREASE TO 40-50 ALONG WITH LOWERING HIGHS. LOWS WILL LIKELY REMAIN IN THE LOW TO MID 70S AS COOLER AIR REMAINS TRAPPED NORTHWEST OF THE REGION AND CLOUD COVER WILL LINGER. THINK COVERAGE OF PRECIP WILL DECREASE OVERNIGHT BUT SHOWERS ARE LIKELY TO LINGER OVERNIGHT SO WILL MAINTAIN LOW CHC POP. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY. PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON HOURS...DIMINISHING TONIGHT. OVERNIGHT...MODELS ARE PRETTY AGGRESSIVE WITH BRINGING IN LIFR FOG/STRATUS INLAND. ONLY MODERATE CONFIDENCE WITH THIS SCENARIO...GIVEN A POSSIBILITY OF A VARIETY OF LAYERS OF CLOUDS DEBRIS FROM THE WEAKENING SHORT WAVE. THURSDAY...BECOMING VFR BY 13Z OR SO. WINDS WILL BE LIGHT... SWINGING TO THE SOUTHWEST AS HIGH PRESSURE SHIFTS A BIT MORE OFFSHORE. EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND MONDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 2 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10 KNOTS WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW THERE HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A SMALL CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE OF HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH TOWARDS THE COAST. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 2 PM WEDNESDAY...HIGH PRESSURE WILL PRESIDE OFFSHORE RESULTING IN SOUTHERLY FLOW ACROSS THE COASTAL WATERS DURING THE SHORT TERM PERIOD. THE PRESSURE GRADIENT WILL LIKELY SUPPORT WINDS IN THE 10-15 KT RANGE...WITH SOME ENHANCEMENT EACH DAY FROM THE SEA BREEZE CIRCULATION. SEAS WILL LIKELY AVERAGE 3 FT AWAY FROM THE COAST THURSDAY AND 3-4 FT BY FRIDAY AFTERNOON...WITH HIGHER FREQUENCY WAVES DOMINATING THE WAVE SPECTRUM. LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 2 PM WEDNESDAY...BERMUDA HIGH AND PIEDMONT TROUGH WILL MAINTAIN SOUTH TO SOUTHWEST FLOW OVER THE WATERS THROUGH THE PERIOD. RELATIVELY WEAK GRADIENT WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE WITH HIGHEST VALUES IN THE AFTERNOON/EVENING. SPEEDS MAY INCREASE A LITTLE LATE IN THE PERIOD AS COLD FRONT DROPS IN FROM THE NORTHWEST AND PINCHES GRADIENT. SEAS OF 2 TO 4 FT WILL BE A COMBINATION OF DOMINANT SOUTHERLY WIND WAVE AND EAST TO SOUTHEAST SWELL. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DRH SHORT TERM...SRP LONG TERM...III AVIATION...DL/DRH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
127 PM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA MONDAY AND TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 115 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF INTERSTATE 95. THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN WILLIAMSBURG COUNTY. A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS CONTINUE. MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR THE BEACHES AROUND SUNRISE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE SEA-BREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS UNCHANGED FOR THE MOST PART. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY. PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON HOURS...DIMINISHING TONIGHT. OVERNIGHT...MODELS ARE PRETTY AGGRESSIVE WITH BRINGING IN LIFR FOG/STRATUS INLAND. ONLY MODERATE CONFIDENCE WITH THIS SCENARIO...GIVEN A POSSIBILITY OF A VARIETY OF LAYERS OF CLOUDS DEBRIS FROM THE WEAKENING SHORT WAVE. THURSDAY...BECOMING VFR BY 13Z OR SO. WINDS WILL BE LIGHT...SWINGING TO THE SOUTHWEST AS HIGH PRESSURE SHIFTS A BIT MORE OFFSHORE. EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND MONDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 115 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10 KNOTS WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW THERE HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A SMALL CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE OF HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH TOWARDS THE COAST. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS. THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN KNOTS. WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT SEAS OF 2-3 FEET. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DRH SHORT TERM...SHK LONG TERM...SHK AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
117 PM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA MONDAY AND TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 115 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF INTERSTATE 95. THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN WILLIAMSBURG COUNTY. A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS CONTINUE. MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR THE BEACHES AROUND SUNRISE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE SEA-BREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS UNCHANGED FOR THE MOST PART. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 12Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY. PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON HOURS...DIMINISHING TONIGHT. SOME LIGHT FOG IS POSSIBLE AFTER 08Z...MAINLY INLAND. EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 115 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10 KNOTS WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW THERE HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A SMALL CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE OF HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH TOWARDS THE COAST. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS. THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN KNOTS. WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT SEAS OF 2-3 FEET. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DRH SHORT TERM...SHK LONG TERM...SHK AVIATION...SGL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
542 PM CDT WED AUG 7 2013 .UPDATE... ISSUED AT 542 PM CDT WED AUG 7 2013 LATEST WATER VAPOR IMAGERY SHOWS A SHORTWAVE NOW WORKING ITS WAY INTO NORTHEAST MONTANA FROM SOUTHERN SASKATCHEWAN. AN AREA OF RAIN SHOWERS CONTINUE TO MOVE INTO NORTHWEST NORTH DAKOTA. THE LATEST RAP HAS A GOOD READ ON THE ACTIVITY AS SCOOTS IT ACROSS THE NORTH CENTRAL THIS EVENING. IN ADDITION...WILL WATCH FOR SHOWERS TO DEVELOP IN THE WEST AND SOUTH CENTRAL EARLY TONIGHT PER RAP MODEL. RADAR SHOWING A WEAK LINE TRYING TO GENERATE FROM NEAR WILLISTON SOUTH TO TROTTERS AT THIS MOMENT. BEST FORCING REMAINS NORTH. THUS WILL CONTINUE WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NORTH THIS EVENING AND ISOLATED SHOWERS/THUNDERSTORMS WEST AND CENTRAL OVERNIGHT. GIVEN THE WEAK INSTABILITY...THUNDER SHOULD REMAIN ISOLATED. MINOR UPDATES TO HOURLY TEMPS/DEWPOINTS AND CHANGED UNCERTAINTY WORDING TO AREAL COVERAGE IN THE WEATHER GROUP BASED ON RADAR. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 338 PM CDT WED AUG 7 2013 CURRENTLY...A STRONG UPPER LEVEL JET AND A SHORTWAVE IMPULSE TRACKING ACROSS SOUTHERN SASKATCHEWAN IS RESPONSIBLE FOR PRODUCING SCATTERED SHOWERS FROM NORTHEAST MONTANA INTO NORTHWEST NORTH DAKOTA. THE SHOWERS ARE EXPECTED TO TRACK EAST AND SOUTH ACROSS THE AREA LATE THIS AFTERNOON AND THIS EVENING. SIMILAR TO THE TRACK OF A SHORTWAVE YESTERDAY. THE MAIN DIFFERENCE IS THE ATMOSPHERE IS MORE STABLE TODAY. HOWEVER...WITH A STRONG UPPER LEVEL JET AND SHORTWAVE...WE CANNOT RULE OUT A FEW THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING...WITH SMALL HAIL AND GUSTY WINDS. HOWEVER IN THE FORECAST WE LIMITED THE BEST CHANCES TO THE NORTH LATE THIS AFTERNOON...AND WITH LIMITED INSTABILITY AND CAPPING ALOFT...WE KEPT A MENTION OF SHOWERS WITH ONLY ISOLATED THUNDERSTORMS. EXPECT PRECIPITATION CHANCES TO DIMINISH AS THE SYSTEM TRACKS SOUTHEAST. BUT THE LATEST RAP AND HRRR HOLD REFLECTIVITIES TOGETHER AS THEY TRACK INTO THE SOUTHEAST CWA AROUND MIDNIGHT. MODELS HAVE TRENDED FARTHER SOUTH WITH THE NEXT WAVE COMING INTO THE AREA AFTER MIDNIGHT. HAVE THEREFORE CONTINUED THE TREND OF LOWERING POPS ACROSS THE AREA. CURRENTLY HAVE CHANCE POPS ACROSS THE FAR SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT...AND HAVE DROPPED POPS ACROSS THE SOUTH ON THURSDAY MORNING. ANOTHER SHORTWAVE MOVING ACROSS ALBERTA TONIGHT WILL DROP SOUTHEAST INTO THE LOCAL AREA THURSDAY AFTERNOON. THIS COULD DEVELOP AN ISOLATED SHOWERS ACROSS THE NORTH DURING THE AFTERNOON. TEMPERATURES WILL REMAIN ON THE COOL SIDE WITH HIGHS RANGING FROM THE 60S NORTH TO THE 70S SOUTH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 338 PM CDT WED AUG 7 2013 CONTINUED BELOW NORMAL TEMPERATURES WILL HIGHLIGHT THE EXTENDED FORECAST. AS HAS BEEN THE PATTERN OVER THE LAST COUPLE WEEKS...NORTHWEST FLOW ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH THE EXTENDED. THIS FAVORS BELOW NORMAL TEMPERATURES WITH HIGHS GENERALLY IN THE 70S...PERHAPS RECOVERING INTO THE LOWER 80S BY MID NEXT WEEK. OVERALL...THE COOLER EDGE OF GUIDANCE HAS BEEN HANDLING THIS PATTERN BETTER...AND THUS UTILIZED A BLEND OF THE BIAS CORRECTED 12 UTC SUITE. IN REGARDS TO PRECIPITATION...WHILE ISOLATED DIURNAL CONVECTION IS HARD TO RULE OUT ANY DAY UNDER NORTHWEST FLOW...THE FAVORED PERIODS FOR PRECIPITATION ARE SATURDAY WITH LEE SURFACE LOW PRESSURE AND AGAIN TUESDAY INTO WEDNESDAY AS PACIFIC ENERGY CRESTS THE UPPER LEVEL INTERMOUNTAIN WEST RIDGE AND PROPAGATES INTO THE NORTHERN PLAINS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 542 PM CDT WED AUG 7 2013 SCT/BKN LOW VFR CIGS WILL CONTINUE THROUGH THE TAF PERIOD UNDER A NORTHWEST UPPER FLOW AND A COUPLE OF UPPER AIR DISTURBANCES RESULTING IN A VCSH MENTION AT KISN/KMOT/KJMS. COULD BE PATCHY FOG DEVELOPING FOR A SHORT PERIOD TOWARD 12Z THURSDAY AT KMOT. WILL MONITOR SATELLITE AND SURFACE OBSERVATIONS BEFORE MENTIONING A PREDOMINATE GROUP IN THE FORECAST. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...TWH LONG TERM...AYD AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
338 PM CDT WED AUG 7 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 338 PM CDT WED AUG 7 2013 CURRENTLY...A STRONG UPPER LEVEL JET AND A SHORTWAVE IMPULSE TRACKING ACROSS SOUTHERN SASKATCHEWAN IS RESPONSIBLE FOR PRODUCING SCATTERED SHOWERS FROM NORTHEAST MONTANA INTO NORTHWEST NORTH DAKOTA. THE SHOWERS ARE EXPECTED TO TRACK EAST AND SOUTH ACROSS THE AREA LATE THIS AFTERNOON AND THIS EVENING. SIMILAR TO THE TRACK OF A SHORTWAVE YESTERDAY. THE MAIN DIFFERENCE IS THE ATMOSPHERE IS MORE STABLE TODAY. HOWEVER...WITH A STRONG UPPER LEVEL JET AND SHORTWAVE...WE CANNOT RULE OUT A FEW THUNDERSTORMS THIS AFTERNOON AND EARLY EVENING...WITH SMALL HAIL AND GUSTY WINDS. HOWEVER IN THE FORECAST WE LIMITED THE BEST CHANCES TO THE NORTH LATE THIS AFTERNOON...AND WITH LIMITED INSTABILITY AND CAPPING ALOFT...WE KEPT A MENTION OF SHOWERS WITH ONLY ISOLATED THUNDERSTORMS. EXPECT PRECIPITATION CHANCES TO DIMINISH AS THE SYSTEM TRACKS SOUTHEAST. BUT THE LATEST RAP AND HRRR HOLD REFLECTIVITIES TOGETHER AS THEY TRACK INTO THE SOUTHEAST CWA AROUND MIDNIGHT. MODELS HAVE TRENDED FARTHER SOUTH WITH THE NEXT WAVE COMING INTO THE AREA AFTER MIDNIGHT. HAVE THEREFORE CONTINUED THE TREND OF LOWERING POPS ACROSS THE AREA. CURRENTLY HAVE CHANCE POPS ACROSS THE FAR SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT...AND HAVE DROPPED POPS ACROSS THE SOUTH ON THURSDAY MORNING. ANOTHER SHORTWAVE MOVING ACROSS ALBERTA TONIGHT WILL DROP SOUTHEAST INTO THE LOCAL AREA THURSDAY AFTERNOON. THIS COULD DEVELOP AN ISOLATED SHOWERS ACROSS THE NORTH DURING THE AFTERNOON. TEMPERATURES WILL REMAIN ON THE COOL SIDE WITH HIGHS RANGING FROM THE 60S NORTH TO THE 70S SOUTH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 338 PM CDT WED AUG 7 2013 CONTINUED BELOW NORMAL TEMPERATURES WILL HIGHLIGHT THE EXTENDED FORECAST. AS HAS BEEN THE PATTERN OVER THE LAST COUPLE WEEKS...NORTHWEST FLOW ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH THE EXTENDED. THIS FAVORS BELOW NORMAL TEMPERATURES WITH HIGHS GENERALLY IN THE 70S...PERHAPS RECOVERING INTO THE LOWER 80S BY MID NEXT WEEK. OVERALL...THE COOLER EDGE OF GUIDANCE HAS BEEN HANDLING THIS PATTERN BETTER...AND THUS UTILIZED A BLEND OF THE BIAS CORRECTED 12 UTC SUITE. IN REGARDS TO PRECIPITATION...WHILE ISOLATED DIURNAL CONVECTION IS HARD TO RULE OUT ANY DAY UNDER NORTHWEST FLOW...THE FAVORED PERIODS FOR PRECIPITATION ARE SATURDAY WITH LEE SURFACE LOW PRESSURE AND AGAIN TUESDAY INTO WEDNESDAY AS PACIFIC ENERGY CRESTS THE UPPER LEVEL INTERMOUNTAIN WEST RIDGE AND PROPAGATES INTO THE NORTHERN PLAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 338 PM CDT WED AUG 7 2013 OTHERWISE VFR CEILINGS EXPECTED THROUGH THE PERIOD. BROUGHT A VCTS/VCSH ACROSS KISN KMOT AND KJMS THIS AFTERNOON AND THIS EVENING. CONVECTION DEVELOPING LATER TONIGHT NOW APPEARS FARTHER SOUTH SO DID NO INCLUDE THUNDER AT TAF SITES FOR THE SYSTEM LATE TONIGHT INTO THURSDAY MORNING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...TWH LONG TERM...AYD AVIATION...TWH
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
312 PM CDT WED AUG 7 2013 .DISCUSSION... THE OUTFLOW BOUNDARY GENERATED FROM THIS MORNINGS MCS CONTINUES TO PUSH ACROSS NORTHERN MISSISSIPPI. SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG AND IN ADVANCE OF THE BOUNDARY AND WILL CONTINUE TO PUSH ACROSS THE REMAINDER OF NORTH MISSISSIPPI OVER THE NEXT COUPLE OF HOURS. THESE STORMS COULD BE STRONG WITH GUSTY WINDS AND HEAVY RAIN. THE BOUNDARY HAS LIMITED HIGH TEMPS ACROSS THE DELTA THOUGH THE SOUTHERN MOST COUNTIES...FROM TALLAHATCHIE TO MONROE...HAVE WARMED INTO THE MID 90S WITH HEAT INDEX VALUES FLIRTING WITH 105 DEGREES. THE REMNANTS OF THE COLD POOL HAVE RESULTED IN A RELATIVELY NICE DAY ACROSS MUCH OF EASTERN AR...THE MO BOOTHEEL AND WEST TENNESSEE WHERE TEMPS AR MOSTLY IN THE 80S TO AROUND 90. THE AIRMASS STILL QUITE STABLE AND PRECIP FREE. TONIGHT...LOOKING AT A FAIRLY QUITE EVENING GIVEN THE WORKED OVER AIRMASS IN PLACE. WENT WITH A 20 POP OVER MOST OF THE AREA AND A 30 POP OVER NE ARKANSAS WHERE THE HRRR IS HINTING AT SOME DEVELOPMENT BEFORE MIDNIGHT. LOOKING AT ANOTHER POTENTIAL MCS SCENARIO LATER TONIGHT AS THE LOW LEVEL JET REDEVELOPS OVER EASTERN OK AND WESTERN AR AND IMPINGES UPON THE WEAK STATIONARY FRONT ACROSS THE AREA. THIS FRONT HAS BEEN HAVING TROUBLE LIFTING NORTH OVER THE LAST COUPLE OF DAYS THANKS TO THE RECENT MCS ACTIVITY AND ASSOCD COLD POOLS. AN AREA OF SHOWERS AND THUNDERSTORMS SHOULD BLOSSOM OVER SRN MISSOURI AFTER MIDNIGHT AND THEN HEAD ESE AND SKIRT THE NORTHERN TIER OF THE MIDSOUTH BY MORNING. POPS WILL DECREASE SHARPLY TOWARD SOUTHERN AREAS OF THE MIDSOUTH. ANOTHER MILD NIGHT ON TAP WITH LOWS IN THE MID 70S. THURSDAY...EXPECT THE MCS TO SKIRT THE NORTHERN TIER AND WEAKEN AS IT SPREADS EAST. BEST CHANCE WILL BE ACROSS NORTHERN AND EASTERN SECTION WITH LESSER CHANCES TOWARD THE SOUTHWEST. MEX GUIDANCE CONTINUES TO BE VERY WARM AND WENT CLOSER TO THE COOLER MET GUIDANCE. EXPECT THAT ANOTHER OUTFLOW BOUNDARY MAY PUSH SOUTH WHICH WILL HELP KEEP A LID ON TEMPS. AREAS SOUTHWEST OF MEMPHIS ARE LIKELY TO GET THE WARMEST AND COULD FLIRT WITH HEAT ADVISORY CRITERIA. THURSDAY NIGHT THROUGH FRIDAY NIGHT...PATTERN REMAINS SIMILAR WITH A BROAD UPPER RIDGE ACROSS THE SOUTHERN U.S AND A WEAK STATIONARY FRONT ACROSS SOUTHERN MISSOURI. EXPECT MCS DEVELOPMENT ALONG THIS FRONT EACH NIGHT WITH THE BEST CHANCES OF PRECIP ALONG THE NORTHERN TIER OF THE MIDSOUTH. CONTINUED TO PREFER THE COOLER MET GUIDANCE THOUGH PARTS OF NORTH MISSISSIPPI AND EAST CENTRAL ARKANSAS WILL FLIRT WITH HEAT ADVISORY CRITERIA ON FRIDAY. SATURDAY THROUGH SUNDAY...CONFIDENCE STARTING TO WANE AT THIS POINT. UPPER RIDGE REMAINS ACROSS THE SOUTHERN U.S. WHILE THE WEAK BOUNDARY TRIES TO SLIP SOUTH INTO THE MIDSOUTH BUT REALLY DOES NOT MOVE MUCH. CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED ACROSS THE REGION. MEX STILL TOO WARM. MONDAY THROUGH WEDNESDAY...MEDIUM RANGE MODELS INDICATE THAT AN UPPER TROF WILL DEVELOP OVER THE EASTERN U.S. EARLY NEXT WEEK. THE GFS IS NOT AS DEEP WITH THE TROF WHICH REESTABLISHES NORTHWEST FLOW ACROSS THE REGION AND KEEPS THE SURFACE BOUNDARY IN THE AREA RESULTING IN A RENEWED MCS PATTERN. THE ECMWF HAS A DEEPER TROF AND ACTUALLY PUSHES THE FRONT SOUTH...SHUTTING OFF PRECIP CHANCES. FOR NOW JUST WENT WITH A COMPROMISE OF 20 POPS AND SLIGHTLY COOLER THAN NORMAL TEMPS. SJM && .AVIATION... 18Z TAF CYCLE SHOWERS AND THUNDERSTORMS HAVE DISSIPATED WITH THE REMNANTS OF A MESOSCALE CONVECTIVE SYSTEM ACROSS THE REGION. HOWEVER...THE SHOWER/THUNDERSTORM FOCUS FOR THIS AFTERNOON WILL BE ACROSS NORTH MISSISSIPPI IN ASSOCIATION WITH AN OUTFLOW BOUNDARY JUST SOUTH/EAST OF MEM AS OF 18Z. THUS...WILL CARRY MENTION OF VCTS AT TUP THROUGH 07/20Z. OTHERWISE...MAINLY RAIN FREE CONDITIONS WILL CONTINUE AT TAF SITES INTO TONIGHT. ANOTHER UPPER LEVEL SHORTWAVE TROUGH MAY DEVELOP ACROSS PORTIONS OF SOUTHERN MISSOURI TONIGHT AND SPREAD INTO THE AREA THURSDAY MORNING. CONFIDENCE IS LOWER WITH OVERALL SHOWER/THUNDERSTORM COVERAGE/PROBABILITIES AND WILL CARRY VCSH FOR THURSDAY MORNING FOR THE TIME BEING. NORTHWEST/NORTH WINDS BETWEEN 4-7 KTS THIS AFTERNOON WILL BACK SOUTH AND DECREASE TO 4 KTS OR LESS TONIGHT AND AVERAGE BETWEEN 4-6 KTS THURSDAY MORNING. PATCHY FOG AND MVFR CONDITIONS POSSIBLE AT JBR/MKL/TUP LATE TONIGHT. CJC && .PRELIMINARY POINT TEMPS/POPS... MEM 77 93 78 94 / 30 30 10 30 MKL 73 88 74 91 / 50 60 30 40 JBR 75 90 75 92 / 50 40 30 40 TUP 75 93 75 93 / 20 40 10 40 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1245 PM CDT WED AUG 7 2013 .UPDATE... UPDATED TO ADD 18Z AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 1009 AM CDT WED AUG 7 2013/ DISCUSSION... THE MCS SKIRTING THE NORTHERN FRINGES OF THE MIDSOUTH HAS BEEN WEAKENING OVER THE LAST COUPLE OF HOURS. THIS COMPLEX WILL SHIFT ESE OVER THE NEXT FEW HOURS AND CONTINUE TO BREAK APART. SOME GRAVITY WAVES THAT...EMANATED FROM THE MCS...ARE VISIBLE ON THE KNQA 88D IMAGERY ACROSS CENTRAL CRITTENDEN AND NORTHERN SHELBY COUNTIES. A MORE SIGNIFICANT BOUNDARY STRETCHES FROM EASTERN LAUDERDALE COUNTY INTO NORTH CROSS COUNTY. THIS MARKS THE LEADING EDGE OF THE COLD POOL. THIS BOUNDARY...COMBINED WITH CLOUD COVER...SHOULD LIMIT THE POTENTIAL HIGH TEMPS TODAY ACROSS MUCH OF THE MIDSOUTH. CURRENT FORECAST IS FAIRLY CONSERVATIVE WITH TEMPS AND THEY LOOK GOOD ATTM. HRRR DOES A GOOD JOB DEPICTING THIS SOUTHWARD MOVING OUTFLOW BOUNDARY AND SHOWS SHOWERS AND THUNDERSTORMS DEVELOPING ALONG IT AS IN MOVES THROUGH AN INCREASINGLY UNSTABLE AIRMASS ACROSS NORTH MISSISSIPPI EARLY THIS AFTERNOON. INCREASED POPS ALONG THE NORTHERN TIER FOR THE REMAINDER OF THE MORNING DUE TO ONGOING MCS. DECREASED POPS ALONG THE NORTHERN TIER THIS AFTERNOON IN ANTICIPATION THAT THE MCS MOVES OFF TO THE ESE. ADDED POPS TO THE SOUTHWEST PART OF THE CWA...DELTA REGION...DUE TO THE OUTFLOW BOUNDARY MOVING THROUGH. UPDATE OUT. SJM PREV DISCUSSION... /ISSUED 236 AM CDT WED AUG 7 2013/ ANOTHER DAY AND ANOTHER MCS TO AFFECT THE MIDSOUTH TODAY. LATEST RADAR IMAGES ARE LOOKING VERY REMINISCENT FROM LAST NIGHT. A LARGE MCS IS CURRENTLY LOCATED OVER SOUTHEAST KANSAS AND NORTHEAST OKLAHOMA AT THIS TIME. THE ONLY DIFFERENCE MAY BE IS THAT THE MCS IS A LITTLE SLOWER SINCE BY THIS TIME LAST NIGHT THE MCS HAD CROSSED INTO SOUTHWEST MISSOURI AND THE SOUTHERN EXTENT IS FURTHER SOUTH THAN LAST NIGHTS. ON ITS CURRENT TRACK EXPECT THE REMNANTS TO MOVE INTO NORTHEAST ARKANSAS BY 8 AM THIS MORNING. MEANWHILE...ADDITIONAL CONVECTION HAS FIRED UP ACROSS SOUTHEAST MISSOURI. THIS IS PRETTY SIMILAR TO WHAT OCCURRED LAST NIGHT. THE CONVECTION IS ON THE NOSE OF THE LOW LEVEL JET AND AHEAD OF AN APPROACHING WARM FRONT THAT IS CURRENTLY LOCATED FROM NEAR JONESBORO TO CORINTH. THE CONVECTION IS EXPECTED TO EXPAND AND INCREASE IN COVERAGE OVER THE NEXT COUPLE OF HOURS. ALREADY SEEING THE FIRST SHOWERS POP UP OBION AND LAKE COUNTIES. THE ATMOSPHERE IS VERY MOIST WITH PW/S OBSERVED AT 2.11 INCHES OFF THE 00Z BNA SOUNDING. ISOLATED LOCATIONS ACROSS THE AREA SUCH AS WEAKLEY COUNTY HAVE ALREADY RECEIVED A LARGE AMOUNT OF RAINFALL. FLASH FLOOD GUIDANCE FOR ONE HOUR IS AT 1.8 FOR WEAKLEY COUNTY SO FLASH FLOODING WILL BE A THREAT AGAIN TODAY FROM ANY THUNDERSTORMS THAT DEVELOP OVER THE AREA. EXPECT BY MIDDAY...CONVECTION WILL BE THE GREATEST ACROSS WEST TENNESSEE NEAR THE TENNESSEE RIVER. CLOUDS AND CONVECTION WILL KEEP TEMPERATURES DOWN ACROSS AT LEAST THE NORTHEAST HALF OF THE CWA. EXPECT HIGHS IN THE LOWER TO MID 80S. MEANWHILE...ACROSS THE SOUTHWEST HALF OF THE CWA TEMPERATURES SHOULD GET UP INTO THE LOWER TO MID 90S UNLESS ABUNDANT CIRRUS FROM MCS KEEPS CONDITIONS COOLER. DEPENDING ON DEWPOINTS...PHILLIPS COUNTY ARKANSAS AND PORTIONS OF NORTHWEST MISSISSIPPI MAY NEED TO BE MONITORED FOR A HEAT ADVISORY. NOT CONFIDENT AT THIS POINT TO ISSUE ONE DUE TO THE AMOUNT OF CLOUD COVER HEADING TOWARD THE MIDSOUTH AT THIS TIME. MODELS SUGGEST THE FRONTAL BOUNDARY WILL BE LOCATED NEAR THE MO/AR BORDER THIS EVENING. EXPECT THE BOUNDARY TO BE THE MAIN SOURCE OF CONVECTION. CAN/T RULE OUT ANOTHER MCS DEVELOPING AS WELL THUS WILL KEEP HIGHEST POPS ACROSS THE NORTHERN AREAS. CONFIDENCE IN FORECAST DROPS OFF AFTER TONIGHT. MODELS SUGGEST FRONT MAY LIFT NORTHWARD INTO MISSOURI THURSDAY NIGHT INTO FRIDAY THUS ANY MCS WOULD STAY NORTH OF THE CWA THURSDAY NIGHT INTO FRIDAY MORNING. WILL THIS HAPPEN...WHO KNOWS. HOWEVER...AT LEAST DIURNAL CONVECTION SHOULD STILL BE POSSIBLE ON FRIDAY. THE COLD FRONT SHOULD SAG SOUTH INTO THE CWA OVER THE WEEKEND AND BRING DECENT CHANCES FOR SHOWERS AND THUNDERSTORMS. HAVE BUMPED UP POPS FOR SATURDAY AS A RESULT. HOW FAR SOUTH THE FRONT GOES REMAINS A QUESTION THAT THE 00Z GFS AND 00Z ECMWF DIFFER ON REGARDING THEIR SOLUTIONS. AS A RESULT...HAVE LEFT FORECAST AS IS FOR MONDAY AND TUESDAY. KRM && .AVIATION... 18Z TAF CYCLE SHOWERS AND THUNDERSTORMS HAVE DISSIPATED WITH THE REMNANTS OF A MESOSCALE CONVECTIVE SYSTEM ACROSS THE REGION. HOWEVER...THE SHOWER/THUNDERSTORM FOCUS FOR THIS AFTERNOON WILL BE ACROSS NORTH MISSISSIPPI IN ASSOCIATION WITH AN OUTFLOW BOUNDARY JUST SOUTH/EAST OF MEM AS OF 18Z. THUS...WILL CARRY MENTION OF VCTS AT TUP THROUGH 07/20Z. OTHERWISE...MAINLY RAIN FREE CONDITIONS WILL CONTINUE AT TAF SITES INTO TONIGHT. ANOTHER UPPER LEVEL SHORTWAVE TROUGH MAY DEVELOP ACROSS PORTIONS OF SOUTHERN MISSOURI TONIGHT AND SPREAD INTO THE AREA THURSDAY MORNING. CONFIDENCE IS LOWER WITH OVERALL SHOWER/THUNDERSTORM COVERAGE/PROBABILITIES AND WILL CARRY VCSH FOR THURSDAY MORNING FOR THE TIME BEING. NORTHWEST/NORTH WINDS BETWEEN 4-7 KTS THIS AFTERNOON WILL BACK SOUTH AND DECREASE TO 4 KTS OR LESS TONIGHT AND AVERAGE BETWEEN 4-6 KTS THURSDAY MORNING. PATCHY FOG AND MVFR CONDITIONS POSSIBLE AT JBR/MKL/TUP LATE TONIGHT. CJC && .PRELIMINARY POINT TEMPS/POPS... MEM 92 77 93 78 / 20 30 20 10 MKL 86 73 88 74 / 60 50 50 20 JBR 88 75 90 75 / 50 30 30 20 TUP 93 74 92 74 / 40 20 40 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1218 PM CDT WED AUG 7 2013 .AVIATION... Scattered altocumulus has persisted over the eastern counties this morning with otherwise clear skies across West Central Texas. We`ll see a surface based cu field develop by 20z with isolated showers and thunderstorms possible, mainly west of a KSOA to KBWD line. I did include VCSH for KABI and KSJT for the afternoon hours but given the spatial uncertainty, I left mention of thunder out of the current forecast. Any storms that develop this afternoon are expected to dissipate by 02z. Winds will veer to a west to southwest direction at KSJT and KSOA this afternoon with predominantly south winds elsewhere. Expect occasional gusts exceeding 15 kts but sustained winds will remain less than 12 kts. Johnson && .PREV DISCUSSION... /ISSUED 913 AM CDT WED AUG 7 2013/ UPDATE... Isolated convection is ongoing over West TX this morning but this activity is expected to dissipate over the next 1-2 hours. Scattered altocumulus castellanus (ACCAS) have developed over portions of West Central TX, indicating some mid level instability. We`ll see relatively quiet weather conditions through early afternoon with a surface based cu field developing after noon. With temperatures warming well above 100 degrees, we should not have any trouble tapping into this instability. Low-level forcing will be tied to a surface trough although convergence will not be all that strong. On the water vapor loop, the primary feature of interest is the compact upper cyclone found to our south near the Big Bend. This low is favorably located to enhance upper-level divergence across West Central TX today. This could yield slightly better convective coverage than I`m currently anticipating. I did change the thunderstorms in the forecast to areal qualifiers and made minor changes in the dewpoint, wind and sky grids. The public and fire weather forecast products have been updated. Johnson PREV DISCUSSION... /ISSUED 647 AM CDT WED AUG 7 2013/ DISCUSSION... See 12Z aviation discussion below. AVIATION... VFR conditions will prevail across the terminals the next 24 hours. Isolated to widely scattered thunderstorms may develop late this afternoon and early evening across western portions of the Big Country, Concho Valley and northern Edwards Plateau. However, limited coverage will preclude mentioning in the TAFS at this time. PREV DISCUSSION... /ISSUED 448 AM CDT WED AUG 7 2013/ SHORT TERM... The main concern today will be convective chances late this afternoon and evening and heat advisory conditions across the Big Country. The upper level high will be positioned over eastern Texas today with a surface trough situated over our western counties by late afternoon. A cold front currently over southern Kansas is expected to drop south into northwest Texas by afternoon and become stationary through the evening hours. Compressional warming ahead of the front along with 850 millibar temperatures between 28 and 30 degrees Celsius will result in very hot temperatures again today. The hottest temperatures will occur across the northeastern half of the Big Country where compressional warming effects will be greatest. Afternoon highs across this area will top out between 103 and 106 degrees with corresponding heat indices between 104 and 107 degrees. Elsewhere, expected highs between 100 and 104 degrees with slightly lower heat indices. Included Jones County to the latest heat advisory which also covers Haskell, Throckmorton and Shackelford counties until 8 pm this evening. The aforementioned surface trough will be a focus for convective development by late afternoon across western counties as the cap weakens with intense heating. The NAM seems to have a better handle on this scenario as does the HRRR with both showing development along the trough axis by late afternoon. Went ahead and added slight pops generally west of a Throckmorton, Eden to Sonora line through early evening. While widespread severe weather is not expected, inverted V profiles with large dewpoint depressions will be favorable for a few microbursts with the stronger cells. Storms will be diurnally driven and should dissipate by mid to late evening with loss of heating. Low temperatures tonight will generally be in the mid and upper 70s. 24 LONG TERM... Above normal temperatures will continue for all of West Central Texas through much of the extended forecast, although showers and thunderstorms may provide brief relief from the heat. Another hot day is forecast, although 850mb temperatures are slightly cooler than what we are expecting this afternoon. Highs should range from 99 to 102 over the southern counties to 101 to 104 across much of the Big Country. Isolated to scattered showers and thunderstorms are expected to develop along a surface trough across our western counties by late afternoon. I included a slight chance of showers and thunderstorms across mainly the western half of the area...with a chance across the extreme western Concho Valley and Big Country. In the meantime...a weak cold front will approach the northern Big Country during the late evening or early morning hours. Scattered showers and thunderstorms will be possible with the boundary...and I have kept a slight chance POPs going through the overnight hours for much of the Big Country. I trended my dewpoint temperatures closer to the more moist NAM through Friday. Model differences arise in the placement of a cold front across the region on Friday and Saturday. The NAM is the fastest with the boundary, stalling it across the Concho Valley during the early morning hours Friday, while the GFS and ECMWF are about 6 to 10 hours slower. Given the expected boundary across area and decent moisture to work with...I believe showers and thunderstorms will develop across parts of the Big Country, Heartland, and Concho Valley during the late afternoon/evening hours. Timing of the front will make a difference on both high temperatures and placement of best POPS, and for now I have kept a slight chance across generally the northern half of the region, and I tweaked highs down slightly. Although I cannot rule out an isolated shower or thunderstorms Saturday as the diffuse boundary remains in the area, confidence is not high enough to include in the forecast at this time. An inverted trough/low will move across South Texas Sunday into Monday, then into northern Mexico. Although the best dynamics associated with this feature will remain south of area area, it should pull in better gulf moisture Sunday and Monday. I cannot rule out diurnally driven isolated showers and thunderstorms during the afternoon hours, across mainly the southeast counties, but for now I have kept the forecast dry. High temperatures should be slightly above seasonal normals, generally in the mid and upper 90s, with lows in the 70s. Daniels && .PRELIMINARY POINT TEMPS/POPS... ABILENE 103 78 100 77 97 / 20 20 20 20 20 SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20 JUNCTION 103 76 101 73 100 / 10 10 5 5 10 && .SJT WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON. && $$ 25
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
636 PM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL MOISTURE UP THE EASTERN SEABOARD. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY/... AS OF 635 PM EDT WEDNESDAY... NOT A LOT OF BIG CHANGES EARLY THIS EVENING. OUR FOCUS FOR THE BEST COVERAGE OF SHOWERS AND STORMS HEADING INTO THE EVENING REMAINS ACROSS THE MOUNTAINS...AND PERHAPS ONE OR TWO TIERS OF COUNTIES EAST OF THE CREST OF THE BLUE RIDGE. LATEST LOCAL AND REGIONAL RADAR TRENDS SHOW THE FORECAST DECREASE IN COVERAGE AND INTENSITY. THIS TREND IS EXPECTED TO CONTINUE THROUGH THE EVENING. HAVE TWEAKED TRENDS IN HOURLY TEMPERATURES AND DEW POINTS TO REFLECT THE LATEST OBSERVATIONS AND EXPECTED TRENDS THROUGH THE EVENING. AS OF 340 PM EDT WEDNESDAY... SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING WILL DIMINISH WITH THE LOSS OF SOLAR HEATING TONIGHT. CONTINUED THE MENTION OF HEAVY RAIN WITH THUNDERSTORMS BECAUSE SOME OF THE THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. HOWEVER...NOT EXPECTING WIDESPREAD FLASH FLOODING WITH 1 FFG RELATIVELY HIGH RANGING FROM 1.6 TO 3 INCHES. LOCAL WATER PROBLEMS ARE POSSIBLE DEPENDING ON EVOLUTION AND TRACK OF THUNDERSTORMS. PLACED THE HIGHEST POPS IN THE WEST AND TAPER OFF AS ONE HEAD SOUTHEAST TONIGHT. THERE IS THE POTENTIAL FOR SOME STORMS MOVE INTO THE WESTERN CWA LATE TONIGHT INTO THURSDAY MORNING AS DEPICTED ON HRRR AND ECMWF. WENT WITH WARMER MOS LOW TEMPERATURES FROM THE LOWER 60S IN THE MOUNTAINS TO AROUND 70 DEGREES IN THE SOUTHEAST. ISOLATED SHOWERS THURSDAY MORNING WILL BECOME SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS THURSDAY AFTERNOON AND EVENING AS WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL WIND FLOW. WITH PRECIPITABLE WATER FORECAST AROUND 2 INCHES AND SOME CAPE...THERE COULD BE SOME THUNDERSTORMS WITH LOCALLY HEAVY RAINS. A FEW OF THE STORMS COULD BE STRONG TO SEVERE ACROSS THE NORTH AS SPC HAS A 5 PERCENT CHANCE FOR A SEVERE STORMS ON THURSDAY. PLAYED HIGH TEMPERATURES ON THURSDAY FROM THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE PIEDMONTS. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 400 PM EDT WEDNESDAY... WITH A CLOSED LOW OVER THE UPPER GREAT LAKES AND A BROAD UPPER RIDGE FROM THE WESTERN ATLANTIC THROUGH THE ARKLATEX...A STATIONARY BOUNDARY WILL REMAIN NEAR OUR REGION THROUGH THE PERIOD. EVERY DAY WILL FEATURE SHOWERS AND STORMS...WITH PERHAPS FRIDAY BEING THE WETTEST DAY. THE BOUNDARY PERHAPS SINKS A LITTLE FURTHER SOUTH AND WITH A WESTERLY/DOWNSLOPING WIND DEVELOPING...THERE MAY BE LESS COVERAGE AND MORE FOCUS ACROSS SOUTHSIDE VIRGINIA AND THE NC PIEDMONT. WITH LITTLE OR NO FLOW...BACKBUILDING AND/OR COLLIDING STORMS...AND HIGH PWATS...THE OPPORTUNITY FOR FLASH FLOODING WILL CONTINUE WITH A FLASH FLOOD WATCH PERHAPS NEEDED AT SOME POINT BASED ON ANTECEDENT CONDITIONS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 400 PM EDT WEDNESDAY... WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... AS OF 130 PM EDT WEDNESDAY... NUMEROUS MVFR SHOWERS AND THUNDERSTORMS EXPECTED IN THE WEST WITH ISOLATED TO SCATTERED COVERAGE OF STORMS IN THE EAST. PATCHES OF LOW CLOUDS IFR/LIFR WILL PERSIST ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS THIS AFTERNOON INTO TONIGHT. LWB AND BLF TAF SITES HAVE THE BEST CHANCE FOR A THUNDERSTORM THIS AFTERNOON INTO TONIGHT. HOWEVER...ANY TAF SITE COULD HAVE A THUNDERSTORMS. AS IS THE CASE THIS TIME OF YEAR...THUNDERSTORMS IN A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS DOWN AND LOWER CIGS/VSBYS. TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR VSBYS ARE POSSIBLE. FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...DS/KK SHORT TERM...KM LONG TERM...KM AVIATION...WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
400 PM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL MOISTURE UP THE EASTERN SEABOARD. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY/... AS OF 340 PM EDT WEDNESDAY... SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING WILL DIMINISH WITH THE LOSS OF SOLAR HEATING TONIGHT. CONTINUED THE MENTION OF HEAVY RAIN WITH THUNDERSTORMS BECAUSE SOME OF THE THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. HOWEVER...NOT EXPECTING WIDESPREAD FLASH FLOODING WITH 1 FFG RELATIVELY HIGH RANGING FROM 1.6 TO 3 INCHES. LOCAL WATER PROBLEMS ARE POSSIBLE DEPENDING ON EVOLUTION AND TRACK OF THUNDERSTORMS. PLACED THE HIGHEST POPS IN THE WEST AND TAPER OFF AS ONE HEAD SOUTHEAST TONIGHT. THERE IS THE POTENTIAL FOR SOME STORMS MOVE INTO THE WESTERN CWA LATE TONIGHT INTO THURSDAY MORNING AS DEPICTED ON HRRR AND ECMWF. WENT WITH WARMER MOS LOW TEMPERATURES FROM THE LOWER 60S IN THE MOUNTAINS TO AROUND 70 DEGREES IN THE SOUTHEAST. ISOLATED SHOWERS THURSDAY MORNING WILL BECOME SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS THURSDAY AFTERNOON AND EVENING AS WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL WIND FLOW. WITH PRECIPITABLE WATER FORECAST AROUND 2 INCHES AND SOME CAPE...THERE COULD BE SOME THUNDERSTORMS WITH LOCALLY HEAVY RAINS. A FEW OF THE STORMS COULD BE STRONG TO SEVERE ACROSS THE NORTH AS SPC HAS A 5 PERCENT CHANCE FOR A SEVERE STORMS ON THURSDAY. PLAYED HIGH TEMPERATURES ON THURSDAY FROM THE MID 70S IN THE MOUNTAINS TO THE MID 80S IN THE PIEDMONTS. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 400 PM EDT WEDNESDAY... WITH A CLOSED LOW OVER THE UPPER GREAT LAKES AND A BROAD UPPER RIDGE FROM THE WESTERN ATLANTIC THROUGH THE ARKLATEX...A STATIONARY BOUNDARY WILL REMAIN NEAR OUR REGION THROUGH THE PERIOD. EVERY DAY WILL FEATURE SHOWERS AND STORMS...WITH PERHAPS FRIDAY BEING THE WETTEST DAY. THE BOUNDARY PERHAPS SINKS A LITTLE FURTHER SOUTH AND WITH A WESTERLY/DOWNSLOPING WIND DEVELOPING...THERE MAY BE LESS COVERAGE AND MORE FOCUS ACROSS SOUTHSIDE VIRGINIA AND THE NC PIEDMONT. WITH LITTLE OR NO FLOW...BACKBUILDING AND/OR COLLIDING STORMS...AND HIGH PWATS...THE OPPORTUNITY FOR FLASH FLOODING WILL CONTINUE WITH A FLASH FLOOD WATCH PERHAPS NEEDED AT SOME POINT BASED ON ANTECEDENT CONDITIONS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 400 PM EDT WEDNESDAY... WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... AS OF 130 PM EDT WEDNESDAY... NUMEROUS MVFR SHOWERS AND THUNDERSTORMS EXPECTED IN THE WEST WITH ISOLATED TO SCATTERED COVERAGE OF STORMS IN THE EAST. PATCHES OF LOW CLOUDS IFR/LIFR WILL PERSIST ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS THIS AFTERNOON INTO TONIGHT. LWB AND BLF TAF SITES HAVE THE BEST CHANCE FOR A THUNDERSTORM THIS AFTERNOON INTO TONIGHT. HOWEVER...ANY TAF SITE COULD HAVE A THUNDERSTORMS. AS IS THE CASE THIS TIME OF YEAR...THUNDERSTORMS IN A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS DOWN AND LOWER CIGS/VSBYS. TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR VSBYS ARE POSSIBLE. FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP/KK NEAR TERM...KK SHORT TERM...KM LONG TERM...KM AVIATION...WP/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
141 PM EDT WED AUG 7 2013 .SYNOPSIS... HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 120 PM EDT WEDNESDAY... CONVECTION DEVELOPING THIS AFTERNOON IN THE MOIST UNSTABLE AIR AS HIGHLIGHTED BY RNKWRFARW AND HRRR. THUNDERSTORMS FIRE UP DURING NEXT COUPLE OF HOURS WHERE LOW LEVEL LAPSE RATE HIGHEST ACROSS WEST VIRGINIA AS SEEN ON SPC MESOSCALE ANALYSIS. ISOLATED STORMS ALSO FORMING IN THE PIEDMONT. HOWEVER...THE BEST COVERAGE SHOULD REMAIN IN THE WEST. MADE SOME MINOR ADJUSTMENTS IN ISC GRIDS. AS OF 950 AM EDT WEDNESDAY... THIS MORNING 8AM/12Z RNK SOUNDING SHOWED THAT A WEST FLOW CONTINUES ABOVE LOW LEVEL SOUTHERLY FLOW AND PWATS HAVE CLIMB TO 1.31 INCHES. HRRR AND RNKWRF-ARW INDICATED THAT BEST COVERAGE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL BE ACROSS THE WEST MOUNTAINS. CONTINUED THE MENTION OF HEAVY RAIN WITH AFTERNOON THUNDERSTORMS BECAUSE SOME OF THE THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. MADE SOME ADJUSTMENTS IN POPS AND WEATHER. INCREASED POPS ACROSS SOUTHWEST PORTIONS OF FORECAST AREA LATE MORNING INTO THIS AFTERNOON. ADJUSTED TEMPERATURES AND DEW POINTS ACCORDING TO LATEST OBS AND TRENDS. MORE CHANGES LATER THIS MORNING. AS OF 710 AM EDT WEDNESDAY... JUST A SHOWER OR TWO OUT THERE THIS MORNING ACROSS THE MOUNTAINS INTO THE ROANOKE VALLEY. ALSO DENSE FOG HAS BECOME AN ISSUE ACROSS THE BLUE RIDGE ALONG THE I-77 CORRIDOR AND SHOULD BURN OFF BY 14Z. LATEST MODELS ARE ADVERTISING SOME DIFFERENCES THIS MORNING. THE 06Z NAM/GFS 00Z ECMWF ARE SHOWING CONVECTION ACROSS E TN/NRN GA BUT OVERDOING THE COVERAGE. THE ECWMF HOWEVER IS DOING A BETTER JOB HANDLING THE MCS ACROSS MO INTO WRN KY. FOR THIS MORNING WILL KEEP CHANCE POPS INTO THE WEST PER CONVECTION POPPING ACROSS ERN KY ATTM...WITH LESS THREAT IN THE PIEDMONT. STILL LOOKS LIKE BEST CONVERGENCE ACROSS THE NC MTNS INTO FAR SRN WV THIS AFTERNOON...SO NO CHANGES TO POPS THERE WITH HIGH CHANCE TO LOW LIKELY. PREVIOUS VALID DISCUSSION... GIVEN HIGH PWATS ADDED HEAVY RAIN THREAT WITH THE THUNDERSTORMS. CANNOT RULE OUT ISOLATED FLASH FLOODING OR SVR SO WILL MENTION THAT IN THE HWO. LIKE TUESDAY...SKY COVER WILL BE VARIABLE BUT THINK MORE CLOUDS THAN SUN EXPECTED AND KEPT TEMPS CLOSE TO A MODEL/MOS BLEND FOR HIGHS WITH MID TO UPPER 70S WEST TO LOWER TO MID 80S EAST. TONIGHT...THERE IS A POTENTIAL FOR WHAT IS GOING ON IN KS/MO THIS MORNING TO GET CAUGHT UP IN THE WESTERLIES AS FLOW FLATTENS...MOVING TOWARD OUR MOUNTAINS OVERNIGHT. HOWEVER...MODELS ARE FAVORING KEEPING THE AXIS OF BEST LIFT...LOW LVL FORCING ACROSS THE OHIO/TN VALLEYS AND MAY SEE SOME STORMS MOVE INTO THE WESTERN CWA LATE. SO FOR NOW WILL KEEP HIGH CHANCE IN THE FAR WEST TONIGHT WITH DIMINISHING POPS IN THE EAST. WITH CONTINUED MORE CLOUDS AND HIGH MOIST CONTENT LOW TEMPS WILL BE IN THE 60S. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... AS OF 400 AM EDT WEDNESDAY... WILL START THURSDAY OFF WITH ONLY ISOLATED SHOWERS THAT WILL BECOME WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS DURING THE AFTERNOON AND EVENING AS WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL WIND FLOW. WILL AGAIN SEE A THREAT OF LOCALLY HEAVY RAIN AS WEAKER UPPER LEVEL WINDS ASSOCIATED WITH THE BUILDING RIDGE TO OUR SOUTH RESULT IN SLOWER STORM MOVEMENT... WHILE DEEP ATMOSPHERIC MOISTURE POOLS AHEAD OF A COLD FRONT SITUATED NEAR THE OHIO RIVER. SHOWERS AND THUNDERSTORMS WILL BE MORE WIDESPREAD ON FRIDAY AS A SHORTWAVE ROTATING AROUND AN UPPER LOW NORTH OF THE GREAT LAKES WILL BEGIN TO NUDGE THE COLD FRONT FURTHER SOUTH. STRONG MOISTURE ADVECTION SOUTH OF THE FRONT WILL PUSH PRECIPITABLE WATER VALUES TO 2 INCHES OR MORE FOR MOST OF OUR AREA...AND AFTERNOON HEATING WILL PUSH CAPES INTO THE 1000 TO 1500 J/KG RANGE. WIND SPEEDS ALOFT WILL BE A LITTLE STRONGER...BUT BELIEVE THAT STORMS WHICH DEVELOP WITH AFTERNOON HEATING WILL BECOME VERY EFFICIENT RAINFALL PRODUCERS... ENHANCING THE FLASH FLOOD THREAT FOR OUR AREA. WOULD ALSO NOT BE SURPRISED TO SEE A FEW STORMS BECOME SEVERE...ESPECIALLY ACROSS THE PIEDMONTS...CAPABLE OF PRODUCING DAMAGING WINDS. MODELS ARE IN GENERAL AGREEMENT IN THEIR LATEST RUNS THAT THE SHORTWAVE TROUGH MOVING EAST ACROSS CANADA WILL ADVANCE THE COLD FRONT INTO NORTHERN VIRGINIA AND CENTRAL WEST VIRGINIA BY SATURDAY AFTERNOON. WILL GO WITH THE MODEL CONSENSUS ON FRONTAL PLACEMENT... KEEPING IN MIND THAT DISTURBANCES IN THE ZONAL FLOW ALOFT MAY CAUSE THE FRONT TO WAVER NORTH AND SOUTH AT TIMES. THAT STATED...TRULY DRIER AIR IS EXPECTED TO REMAIN WELL TO THE NORTH THROUGH SATURDAY NIGHT...AND WILL STILL EXPECT SCATTERED SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON AND EVENING. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 400 AM EDT WEDNESDAY... LOOKING AT BETTER AGREEMENT IN THE LONG TERM MODELS FOR EARLY NEXT WEEK...WITH BOTH THE GFS AND ECMWF SOLUTIONS PUSHING THE COLD FRONT INTO THE CAROLINAS BY MONDAY MORNING. THE SOUTHWARD PUSH OF THE FRONT WILL MEAN ONLY SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS MONDAY AND TUESDAY...MAINLY SOUTH OF THE INTERSTATE 81 CORRIDOR. WILL BE KEEPING AN EYE ON ANOTHER WAVE ALOFT DROPPING OUT OF CANADA AND LIFTING MOISTURE BACK NORTH BY MIDWEEK...WHICH MAY SIGNAL A RETURN OF MORE WIDESPREAD CONVECTION. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 130 PM EDT WEDNESDAY... NUMEROUS MVFR SHOWERS AND THUNDERSTORMS EXPECTED IN THE WEST WITH ISOLATED TO SCATTERED COVERAGE OF STORMS IN THE EAST. PATCHES OF LOW CLOUDS IFR/LIFR WILL PERSIST ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS THIS AFTERNOON INTO TONIGHT. LWB AND BLF TAF SITES HAVE THE BEST CHANCE FOR A THUNDERSTORM THIS AFTERNOON INTO TONIGHT. HOWEVER...ANY TAF SITE COULD HAVE A THUNDERSTORMS. AS IS THE CASE THIS TIME OF YEAR...THUNDERSTORMS IN A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS DOWN AND LOWER CIGS/VSBYS. TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR VSBYS ARE POSSIBLE. FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...KK/WP SHORT TERM...NF LONG TERM...JH AVIATION...WP/KK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
230 PM MDT WED AUG 7 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 300 PM MDT WED AUG 7 2013 SHOWERS AND THUNDERSTORMS WERE DEVELOPING EARLY THIS AFTERNOON OVER VARIOUS PARTS OF THE CWA. THE ACTIVITY IS SLOWLY BECOMING MORE INTENSE...BUT SO FAR HAS BEEN HINDERED SOME BY THE CIRRUS CURRENTLY OVER THE AREA. AT LEAST A SCATTERED COVERAGE OF STORMS SHOULD CONTINUE THROUGH EARLY THURSDAY MORNING. THE ATMOSPHERE IS MOIST AND UNSTABLE WITH SURFACE FORCING NEAR THE MOUNTAINS. IN ADDITION...A SHORTWAVE TROUGH NEAR THE FOUR CORNERS REGION EARLY THIS AFTERNOON WILL MOVE NORTHEAST AND NEAR THE CWA THROUGH EARLY THURSDAY MORNING. THE MAIN THREAT STILL APPEARS TO BE A PERIOD OF HEAVY RAIN...SMALL HAIL AND GUSTY WINDS THROUGH THE EVENING. THE BEST POTENTIAL FOR SEVERE STORMS WILL BE IN THE NORTH PART OF THE CWA IN THE AREA OF BETTER 0-6 KM SHEAR THROUGH THIS EVENING. AREAS OF LOW CLOUDS AND FOG WILL BE POSSIBLE LATER TONIGHT AND INTO MID MORNING THURSDAY FROM KSNY TO THE SOUTHERN LARAMIE RANGE. BY MIDDAY THURSDAY...HEIGHTS ALOFT BUILD OVER THE ROCKIES WITH A SHORTWAVE RIDGE OVER THE AREA THROUGH FRIDAY. THE PLUME OF MID AND UPPER LEVEL MOISTURE WILL BE MAINLY OVER THE SOUTH PART OF THE CWA THURSDAY AND THEN OVER THE ENTIRE CWA FRIDAY. MOIST BOUNDARY LAYER UPSLOPE WINDS WILL CONTINUE THROUGH FRIDAY WITH SURFACE DEW POINTS IN THE 50S TO THE EAST OF THE LARAMIE RANGE. PRECIPITABLE WATER VALUES THROUGH THAT TIME WILL CONTINUE TO RANGE FROM NEAR ONE HALF INCH OVER SOUTH CENTRAL WYOMING TO AN INCH OVER THE PANHANDLE. A SCATTERED COVERAGE OF AFTERNOON AND EVENING THUNDERSTORMS WILL AGAIN TAKE PLACE OVER THE CWA ON THURSDAY. THEN ON FRIDAY...MODELS MOVE A MORE SIGNIFICANT SHORTWAVE NEAR THE CWA. THAT SHOULD RESULT IN MORE COVERAGE AND PERHAPS HEAVIER RAINFALL. TEMPERATURES WILL BE SIMILAR OVER THE CWA THROUGH FRIDAY WITH READINGS NEAR OR JUST BELOW NORMAL. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 300 PM MDT WED AUG 7 2013 NEW ECMWF 12Z RUN CONTINUES TO BE MORE BULLISH ON QPF...PARTICULARLY WEST OF THE LARAMIE RANGE FRIDAY NIGHT. NAM/WRF BACKS THE ECMWF SOLUTIONS...SO KEPT PRETTY HIGH POPS GOING OUT WEST FRIDAY NIGHT. THIS IS DUE TO A PRETTY POTENT VORT MAX TRACKING NORTHEAST THROUGH THE RIDGE. ITS REALLY SLOW MOVING TO THE NORTHEAST AND BY SATURDAY MORNING...IT FINALLY CLEARS TO CWFA. SO CURRENTLY THINKING IS FOR SHOWERS AND THUNDERSTORMS TO CONTINUE ALL NIGHT...PARTICULARLY OUT WEST AND INTO CONVERSE COUNTY. RESIDUAL MOISTURE AND UPSLOPING WINDS EAST OF THE LARAMIE RANGE WILL AID IN ANOTHER ROUND OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS SATURDAY AND SATURDAY EVENING. WE ARE LOOKING AT THE BROKEN RECORD CONTINUING THROUGH MID WEEK AS MONSOONAL MOISTURE REMAINS OVER THE AREA. ITS A GOOD PROBLEM TO HAVE AS WE ARE STILL WAY BELOW ON RAINFALL...AND THE RAIN KEEPS FIRE WEATHER CONCERNS AT BAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING) ISSUED AT 1046 AM MDT WED AUG 7 2013 LOOKS LIKE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS FOR THIS AFTERNOON. LATEST HRRR FORECAST SHOWING THUNDERSTORMS FORMING ALONG A LINE JUST NORTH OF CHADRON OVER TO LUSK AROUND 19Z...SWEEPING SOUTH THROUGH THE SOUTHERN PANHANDLE BY 00Z. BASED TIMING ON ITS FORECAST. THEN BEHIND THE LINE...WE SEE A NORTHEAST WIND DEVELOPING BEHIND THIS LINE. HRRR AND SREF SHOWING A FAIRLY WIDESPREAD AND PROLONGED LOW CEILING EVENT WITH THESE NORTHEAST UPSLOPING WINDS. BELIEVE THE MOST PROBABLE AREA WILL BE HERE AT KCYS AND KSNY IN THE SOUTHERN PANHANDLE. BUT KAIA AND KBFF COULD ALSO BE IMPACTED. SHOULD THESE AIRPORTS AND THE PANHANDLE RECEIVE GOOD RAINFALL TODAY...THEN CONFIDENCE WILL CERTAINLY GROW THAT IT WILL HAPPEN. && .FIRE WEATHER... ISSUED AT 300 PM MDT WED AUG 7 2013 MONSOONAL MOISTURE WILL REMAIN OVER THE CWA THROUGH AT LEAST FRIDAY. THE RESULT WILL BE AT LEAST A SCATTERED COVERAGE OF MAINLY LATE DAY SHOWERS AND THUNDERSTORMS EACH DAY AND TEMPERATURES AT OR JUST BELOW NORMAL. THE ATMOSPHERE DRIES SOME FOR THE WEEKEND AND EARLY NEXT WEEK AND MAY RESULT IN MARGINAL FIRE WEATHER CONDITIONS FOR THE LOWER ELEVATIONS OF THE WEST PART OF THE CWA. HOWEVER...WINDS IN MOST AREAS WILL BE FAIRLY LIGHT THROUGH EARLY NEXT WEEK. IN GENERAL THAT LEADS TO A REDUCED FIRE WEATHER CONCERN OVER THE CWA DURING THAT TIME. DRY THUNDERSTORMS WILL BE A POSSIBILITY ON SOME DAYS OVER THE LOWER ELEVATIONS OF CARBON COUNTY. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...WEILAND LONG TERM...CLAYCOMB AVIATION...CLAYCOMB FIRE WEATHER...WEILAND
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1055 AM MDT WED AUG 7 2013 .UPDATE... ISSUED AT 1023 AM MDT WED AUG 7 2013 THIS AFTERNOON AND EVENING SHOULD BE FAIRLY ACTIVE OVER MUCH OF THE CWA. THE ATMOSPHERE WILL CONTINUE TO DESTABILIZE THROUGH THE AFTERNOON AND PRECIPITABLE WATER VALUES WILL BE AROUND THREE QUARTERS OF AN INCH. IN ADDITION...THE LOW LEVEL THETA-E RIDGE AXIS WILL BE OVER THE EAST PART OF THE CWA. ALONG WITH SURFACE FORCING...A SHORTWAVE TROUGH CURRENTLY TO OUR SOUTH WILL LIFT NORTH AND AFFECT THE SOUTH THIRD OF THE CWA THIS AFTERNOON AND EVENING. ANOTHER SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTH PART OF THE CWA DURING THAT TIME. STORMS IN THE SOUTH WILL LIKELY PRODUCE A PERIOD OF HEAVY RAIN...GUSTY WINDS AND SMALL HAIL. MEANWHILE...THOSE IN THE NORTH WILL HAVE BETTER SHEAR AND STRONGER STORMS WILL BE POSSIBLE. THERE CONTINUES TO BE A POTENTIAL FOR MORE LANDSPOUTS THIS AFTERNOON AND EVENING WITH THE STORMS. IN A RECENT UPDATE...INCREASED POPS AND ADDED HEAVY RAIN...HAIL AND WINDS WILL THE THUNDERSTORMS. ALSO MADE MINOR ADJUSTMENTS TO THE REST OF THE FIRST PERIOD OF THE FORECAST. && .SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON) ISSUED AT 439 AM MDT WED AUG 7 2013 A FEW ELEVATED WARM ADVECTION SHOWERS OVER THE NEBRASKA PANHANDLE AS OF 10Z. THIS ACTIVITY SHOULD SHIFT EAST OF THE AREA THIS MORNING WITH THE AREA OF STRONGER ISENTROPIC FORCING. HOWEVER... BROAD WEAK FORCING WILL BE IN PLACE ACROSS THE EASTERN 1/2 OF THE FORECAST AREA THROUGH THE REMAINDER OF THE MORNING SO CAN`T RULE OUT ISOLATED THUNDERSTORMS AS THE ELEVATED INSTABILITY IS IN PLACE. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS ON TAP FOR LATE TODAY...BUT COVERAGE AND INTENSITY IS A BIG QUESTION GIVEN THE VERY POOR PERFORMANCE OF SHORT TERM MODELS THE LAST SEVERAL DAYS. SEVERE THREAT APPEARS MINIMAL BUT WILL HAVE TO KEEP A CLOSE EYE ON STORMS THIS AFTERNOON. NAM AND GFS DIFFER SOMEWHAT ON THE CAPE WITH THE NAM INDICATING HIGHER VALUES NEAR 2000 J/KG WHILE THE GFS IS CLOSER TO 1000 J/KG. DEEP LAYER SHEAR NOT AS STRONG AS MANY DAYS THE LAST FEW WEEKS...BUT THERE MAY BE ENOUGH CAPE AND SHEAR FOR A FEW SUPERCELLS THIS AFTERNOON AND EARLY EVENING EAST OF THE LARAMIE RANGE. IT DOES APPEAR THE MAIN POTENTIAL FOR STRONGER STORMS WILL BE IN THE NORTH OVER CONVERSE AND NIOBRARA COUNTY AND THE NORTHERN NEBRASKA PANHANDLE. OF COURSE THAT IS BASED ON CURRENT NAM AND GFS PROJECTIONS WHICH HAVE BEEN SUSPECT AT BEST THE LAST SEVERAL DAYS...SO CONFIDENCE IS LOW. ONE CONCERN IS THE POTENTIAL FOR NON-SUPERCELL TORNADOES/ LANDSPOUTS THIS AFTERNOON. OVER THE LAST WEEK THERE HAVE BEEN TWO LANDSPOUTS NEAR CHEYENNE AND TODAY LOOKS LIKE A VERY FAVORABLE SET UP FOR MORE LANDSPOUT TYPE TORNADOES IN SOUTHEAST WYOMING EAST OF THE LARAMIE RANGE. LAPSE RATES BY EARLY THIS AFTERNOON WILL EXCEED 7 DEG/KG IN THE BOUNDARY LAYER WHILE 0-3 KM CAPE VALUES WILL EXCEED 100 J/KG WHICH IS QUITE HIGH FOR THE 0-3 KM LAYER. THE ONLY OTHER NEEDED INGREDIENT WILL BE A BOUNDARY TO FORM ON. MODELS DO INDICATE A BOUNDARY NEAR OR JUST EAST OF THE LARAMIE RANGE...SO THAT WILL BE SOMETHING TO WATCH AS WELL AS ANY OUTFLOW BOUNDARIES THAT MAY INTERSECT OR INITIATE CONVECTION. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 439 AM MDT WED AUG 7 2013 THURSDAY NIGHT...ISOLATED TO SCATTERED EVENING THUNDERSTORMS ON TAP ALONG AND WEST OF INTERSTATE 25 IN A LOW AND MID LEVEL THETA-E RIDGE AXIS WITH DECENT THETA-E ADVECTION. CONVECTION WILL WANE AFTER MIDNIGHT WITH LOSS OF DAYTIME HEATING AND WITH LESS LIFT FROM MESOSCALE MECHANISMS. FRIDAY...WILL SEE AN INCREASE IN AFTERNOON AND EVENING THUNDERSTORM COVERAGE AS A PASSING SHORTWAVE TROUGH ALOFT AIDS IN DEVELOPMENT OF MECHANICAL UPSLOPE SOUTHEAST LOW LEVEL WINDS ADVECTING INCREASING MOISTURE INTO OUR COUNTIES. BULK OF COVERAGE WILL STRETCH FROM DOUGLAS TO RAWLINS IN CLOSE PROXIMITY TO THE LOW AND MID LEVEL THETA-E RIDGE AXIS. SATURDAY/SUNDAY...LESS THUNDERSTORM COVERAGE AS LOW AND MID LEVEL MOISTURE AND THUNDERSTORM FUEL DECREASES...ALONG WITH WARMING TEMPERATURES ALOFT ACTING TO PROVIDE MORE CONVECTIVE INHIBITION...CIN. MONDAY/TUESDAY...RIDGING ALOFT PREVAILS...LIMITING AFTERNOON AND EVENING THUNDERSTORM COVERAGE. HOWEVER...PERSISTENCE OF LOW LEVEL UPSLOPE AND DIFFERENTIAL HEATING WILL AID IN AT LEAST ISOLATED LATE DAY THUNDERSTORMS EACH DAY...PRIMARILY ALONG THE UPSLOPE FAVORED LOCALES ALONG AND EAST OF THE LARAMIE RANGE AND THE INTERSTATE 25 CORRIDOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING) ISSUED AT 1046 AM MDT WED AUG 7 2013 LOOKS LIKE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS FOR THIS AFTERNOON. LATEST HRRR FORECAST SHOWING THUNDERSTORMS FORMING ALONG A LINE JUST NORTH OF CHADRON OVER TO LUSK AROUND 19Z...SWEEPING SOUTH THROUGH THE SOUTHERN PANHANDLE BY 00Z. BASED TIMING ON ITS FORECAST. THEN BEHIND THE LINE...WE SEE A NORTHEAST WIND DEVELOPING BEHIND THIS LINE. HRRR AND SREF SHOWING A FAIRLY WIDESPREAD AND PROLONGED LOW CEILING EVENT WITH THESE NORTHEAST UPSLOPING WINDS. BELIEVE THE MOST PROBABLE AREA WILL BE HERE AT KCYS AND KSNY IN THE SOUTHERN PANHANDLE. BUT KAIA AND KBFF COULD ALSO BE IMPACTED. SHOULD THESE AIRPORTS AND THE PANHANDLE RECEIVE GOOD RAINFALL TODAY...THEN CONFIDENCE WILL CERTAINLY GROW THAT IT WILL HAPPEN. && .FIRE WEATHER... ISSUED AT 439 AM MDT WED AUG 7 2013 ACTIVE WEATHER PATTERN WILL CONTINUE INTO THE FORESEEABLE FUTURE. MAIN CHANCES FOR RAIN WILL BE ALONG AND EAST OF THE LARAMIE RANGE WITH LESS CHANCES TO THE WEST. MARGINAL CRITICAL FIRE CONDITIONS WILL OCCUR A FEW DAYS OVER CARBON COUNTY OTHERWISE HUMIDITY VALUES WILL BE ON THE HIGH SIDE THROUGH EARLY NEXT WEEK. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ UPDATE...WEILAND SHORT TERM...LIEBL LONG TERM...RUBIN AVIATION...CLAYCOMB FIRE WEATHER...LIEBL