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
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
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