Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/11/13
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
653 PM PDT SAT AUG 10 2013
.DISCUSSION...AS OF 2:06 PM PDT SATURDAY...AN UPPER LOW OFF THE
NORTHERN CA COASTLINE CONTINUES TO DOMINATE THE WEATHER
PATTERN...WITH MODERATE ONSHORE FLOW AND BELOW SEASONABLE NORMAL
TEMPERATURES. THIS AFTERNOON...TEMPERATURES ROSE INTO THE 60S
ALONG THE COAST...TO THE 70S INLAND. ONE OF THE WARMEST SPOTS OF
THE DAY WAS PINNACLES NATIONAL PARK...AT 87 DEGREES. TEMPERATURES
ARE FORECAST TO RISE ANOTHER FEW DEGREES BEFORE SUNSET. THESE
TEMPERATURES ARE BETWEEN 5 AND 10 DEGREES BELOW NORMAL FOR THE
MIDDLE OF AUGUST.
THE MARINE LAYER...CURRENTLY AROUND 1500 FEET...IS FORECAST TO
DEEPEN TO AROUND 2000 FEET AGAIN OVERNIGHT...WITH ABUNDANT STRATUS
INLAND. PATCHY COASTAL DRIZZLE IS ALSO POSSIBLE AGAIN
OVERNIGHT...AS BOTH THE NAM AND HRRR INDICATE MANY AREAS OF 0.01"
OF ACCUMULATION LATE TONIGHT/EARLY SUNDAY MORNING. TEMPERATURES
ARE FORECAST TO FALL INTO THE 50S OVERNIGHT...SIMILAR TO THOSE
OBSERVED LAST NIGHT.
A SUBTLE WARMING TREND IS FORECAST TO TAKE PLACE TOMORROW THROUGH
AT LEAST THE MIDDLE OF NEXT WEEK...AS THE UPPER LOW SHIFTS SLOWLY
NORTH WITH UPPER LEVEL HIGH PRESSURE OVER THE SOUTHWEST US NUDGING
NORTHWEST INTO THE AREA. 850 MB TEMPERATURES ARE FORECAST TO RISE
BETWEEN 1 AND 2 DEGREES C BETWEEN THIS AFTERNOON AND SUNDAY
AFTERNOON...RESULTING IN INLAND TEMPERATURES WARMING INTO THE MID
70S TO MID 80S. IN FACT...SOUTHERN MONTEREY AND SAN BENITO
COUNTIES ARE FORECAST TO REACH THE MID 90S.
THE MARINE LAYER WILL ALSO COMPRESS BEGINNING SUNDAY NIGHT AND
CONTINUING OVER THE NEXT FEW DAYS...AIDING IN THE WARMING TREND.
BY WEDNESDAY...TEMPERATURES INLAND WILL RISE INTO THE UPPER 70S TO
UPPER 80S...NEAR NORMAL FOR THE MIDDLE OF AUGUST.
ON A SIDE NOTE...THE CLIMATE PREDICTION CENTER 8 TO 14 DAY OUTLOOK
(VALID FROM AUGUST 18TH THROUGH AUGUST 24TH) CALL FOR SLIGHTLY
ABOVE NORMAL TEMPERATURES...MAINLY FOR THE INLAND LOCATIONS.
&&
.AVIATION...AS OF 6:50 PM PDT SATURDAY...UPPER LEVEL LOW NORTH OF
THE AREA. FLOW AROUND THE LOW IS PUSHING STRATUS AGAINST THE COAST
AND WILL SPREAD INTO THE MRY AND SFO BAY AREAS EARLY TONIGHT.
LOCAL DRIZZLE POSSIBLE NEAR THE COAST.
VICINITY OF KSFO...MVFR CIGS AFTER 02Z. WEST WINDS GUSTING TO
22-24 KT THROUGH 04Z.
KSFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...STRATUS COVERS THE SRN MRY BAY. CIGS WILL
SPREAD INTO MRY AND SNS BY 02Z. POSSIBLE DRIZZLE AT MRY.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: RILEY
AVIATION/MARINE: W PI
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
442 PM PDT SAT AUG 10 2013
.DISCUSSION...AS OF 2:06 PM PDT SATURDAY...AN UPPER LOW OFF THE
NORTHERN CA COASTLINE CONTINUES TO DOMINATE THE WEATHER
PATTERN...WITH MODERATE ONSHORE FLOW AND BELOW SEASONABLE NORMAL
TEMPERATURES. THIS AFTERNOON...TEMPERATURES ROSE INTO THE 60S
ALONG THE COAST...TO THE 70S INLAND. ONE OF THE WARMEST SPOTS OF
THE DAY WAS PINNACLES NATIONAL PARK...AT 87 DEGREES. TEMPERATURES
ARE FORECAST TO RISE ANOTHER FEW DEGREES BEFORE SUNSET. THESE
TEMPERATURES ARE BETWEEN 5 AND 10 DEGREES BELOW NORMAL FOR THE
MIDDLE OF AUGUST.
THE MARINE LAYER...CURRENTLY AROUND 1500 FEET...IS FORECAST TO
DEEPEN TO AROUND 2000 FEET AGAIN OVERNIGHT...WITH ABUNDANT STRATUS
INLAND. PATCHY COASTAL DRIZZLE IS ALSO POSSIBLE AGAIN
OVERNIGHT...AS BOTH THE NAM AND HRRR INDICATE MANY AREAS OF 0.01"
OF ACCUMULATION LATE TONIGHT/EARLY SUNDAY MORNING. TEMPERATURES
ARE FORECAST TO FALL INTO THE 50S OVERNIGHT...SIMILAR TO THOSE
OBSERVED LAST NIGHT.
A SUBTLE WARMING TREND IS FORECAST TO TAKE PLACE TOMORROW THROUGH
AT LEAST THE MIDDLE OF NEXT WEEK...AS THE UPPER LOW SHIFTS SLOWLY
NORTH WITH UPPER LEVEL HIGH PRESSURE OVER THE SOUTHWEST US NUDGING
NORTHWEST INTO THE AREA. 850 MB TEMPERATURES ARE FORECAST TO RISE
BETWEEN 1 AND 2 DEGREES C BETWEEN THIS AFTERNOON AND SUNDAY
AFTERNOON...RESULTING IN INLAND TEMPERATURES WARMING INTO THE MID
70S TO MID 80S. IN FACT...SOUTHERN MONTEREY AND SAN BENITO
COUNTIES ARE FORECAST TO REACH THE MID 90S.
THE MARINE LAYER WILL ALSO COMPRESS BEGINNING SUNDAY NIGHT AND
CONTINUING OVER THE NEXT FEW DAYS...AIDING IN THE WARMING TREND.
BY WEDNESDAY...TEMPERATURES INLAND WILL RISE INTO THE UPPER 70S TO
UPPER 80S...NEAR NORMAL FOR THE MIDDLE OF AUGUST.
ON A SIDE NOTE...THE CLIMATE PREDICTION CENTER 8 TO 14 DAY OUTLOOK
(VALID FROM AUGUST 18TH THROUGH AUGUST 24TH) CALL FOR SLIGHTLY
ABOVE NORMAL TEMPERATURES...MAINLY FOR THE INLAND LOCATIONS.
&&
.AVIATION...AS OF 4:45 PM PDT SATURDAY...UPPER LEVEL LOW NORTH OF
THE AREA. FLOW AROUND THE LOW IS PUSHING STRATUS AGAINST THE COAST
AND WILL SPREAD INTO THE MRY AND SFO BAY AREAS EARLY TONIGHT.
LOCAL DRIZZLE POSSIBLE NEAR THE COAST.
VICINITY OF KSFO...STRATUS IS NOT AS EXTENSIVE AS YESTERDAY SO
CIGS WILL COME IN SLIGHTLY LATER THAN YESTERDAY. MVFR CONDITIONS
EXPECTED BY 04Z. WEST WINDS GUSTING TO 22-24 KT THROUGH 04Z.
KSFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...STRATUS COVERS THE SRN MRY BAY. CIGS WILL
SPREAD INTO MRY AND SNS BY 02Z. POSSIBLE DRIZZLE AT MRY.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: RILEY
AVIATION/MARINE: W PI
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
348 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO SLOWLY MOVE EAST ACROSS THE REGION
THROUGH TONIGHT. THIS FRONT WILL THEN STALL TO OUR SOUTH THROUGH
MONDAY, WITH A FEW WAVES OF LOW PRESSURE POSSIBLY MOVING ALONG THE
BOUNDARY. ANOTHER COLD FRONT FROM THE WEST WILL TRACK ACROSS THE
REGION DURING TUESDAY, FOLLOWED BY HIGH PRESSURE BUILDING IN FROM
THE GREAT LAKES FOR THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
THE GFS INITIALIZATION LOOKED SLIGHTLY BETTER THAN THE WRF-NMMB AT
MOST LEVELS, ALTHOUGH IT WAS NOT BY MUCH. OVERALL THE OVERNIGHT SPC
HRW WRF-ARW CONTINUES TO LOOK CLOSEST OF THE SOUNDING RUN MESOSCALE
MODELS (HAVE TO BUMP IT UP AN HR OR TWO IN TIMING). IN THE NEARER
TERM REMOVING THE DC CLUSTER THAT IS NOT THERE, THE HRRR SERIES HAS
BEEN A FAIR COMPROMISE BETWEEN THE RAP AND COSPA.
LOOKING AT ALL OF THE MESOSCALE MODELS AND SYNOPTIC SCALE MODELS,
THE GENERAL CONSENSUS IS THAT CONVECTION SHOULD BE PEAKING WITHIN
OUR CWA BETWEEN 20Z AND 22Z. THIS COINCIDES WITH WEAK PVA AND THE
PASSING OF THE LOW LEVEL THETA E RIDGE. THEY HAVE ALSO BEEN PRETTY
CONSISTENT ON THIS ACTIVITY BECOMING THE MAIN THRUST IN OUR CWA
WITH CONVECTION TO OUR WEST WEAKENING. THE AXIS OF MAX MLCAPE IS
OVER OUR CWA SO THIS DOES SEEM LOGICAL IF WE DO RAIN OUT THE
APPROACHING CONVECTION. ITS NOT GOING TO HAVE AS CONDUCIVE
INSTABILITY ONCE THAT BATCH ARRIVES. MAYBE THE CIRRUS BLOW OFF, THE
WEAK LAPSE RATES AND OR THE LACK OF MID LEVEL QVEC CONVERGENCE, WE
HAVE NOT SEEN A LINE FORM AND IF ONE WERE IT LOOKS TO BE PRETTY FAR
EAST IN OUR CWA.
SO FOR THE NEAR NEAR TERM WE FOLLOWED THIS PREMISE WITH HIEST POPS
THRU 22Z. HOWEVER DONT WANT TO DROP THE FLASH FLOOD WATCH UNTIL WE
SEE THIS CONVECTION WEAKEN. THE 10 PM EXPIRATION TIME AS FAR AS THE
HEAVY RAIN PART OF THE WATCH APPEARS IT WILL BE TOO LATE.
SEVERE/STRONG CHANCES LOOK TO REMAIN ISOLATED. WHILE BULK SHEAR
VALUES ARE ADEQUATE IT LOOKS AS THOUGH THE CONVECTION GOING FROM
HIGHER TO LESSER SHEARED VALUES ARE NOT HAVING MUCH SUCCESS. AGAIN
THIS COULD BE RELATED ALSO TO THE WEAK MID LEVEL LAPSE RATES,
UPDRAFTS MAY NOT BE STRONG ENOUGH IN A SHEARED ENVIRONMENT AND NOT
MUCH DRY AIR AROUND (DCAPES ARE NEAR ZERO!!!)
THE FRONT ITSELF IS STILL FAIRLY FAR WEST IN PA AND GETTING IT TO
REACH THE DELAWARE VALLEY MUCH BEFORE 03Z IS UNLIKELY. SO WHILE WE
CARRY THE HIEST POPS EARLY, WE DID CONTINUE SOME CHANCE THROUGH MOST
OF THE EVENING IN OUR CWA.
DEBRIS CLOUDINESS EXPECTED FOR A CHUNK OF THE NIGHT, ESPECIALLY
SOUTHERN HALF. COUPLED WITH SOME WEAK NW WINDS POST FRONTAL, WE DID
NOT DIFFER MUCH FROM STAT GUIDANCE. GIVEN THAT DEW POINTS ARE
SUPPOSE TO DROP OVERNIGHT, DID NOT PUT IN ANY FOG IN THE GRIDS.
CHANCES ARE IF WE ARE WRONG THIS IS MORE OF AN AVIATION CONCERN THAN
PUBLIC.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
A DRY SATURDAY IS FORECAST FOR OUR CWA WITH LOWER HUMIDITY LEVELS.
THE COLD FRONT IS EXPECTED TO CLEAR ALL OF OUR CWA BY 12Z AND THE
FCST INSTABILITY DOES NOT SUPPORT THUNDER, DOESNT SUPPORT SHOWERS
EITHER. MIGHT HAVE A HARD TIME EVEN SUPPORTING MUCH IN THE WAY OF
CUMULUS.
WITH THE JET STREAM PASSING OVERHEAD SOME CIRRUS SHOULD BE AROUND.
THE SHORT WAVE THE GFS IS PASSING ACROSS OUR CWA LOOKS TOO SUSTAINED
BASED ON THE LACK OF THE CONVECTION ASSOCIATED WITH IT DURING THE
PRECEDING 6 TO 12 HOURS. MAX TEMPS LEANED GFS MOS`S WAY BASED ON
FCST 925MB AND 850MB TEMPS AS WELL AS LLVL THICKNESSES. BUT IN SPITE
OF SIMILAR MAX TEMPS TO TODAY, TOMORROW WILL FEEL MUCH BETTER WITH
THE LOWER DEW POINTS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THROUGH THE FIRST PART OF THE LONG TERM, A STALLED FRONTAL BOUNDARY
WILL BE PRESENT OFF TO OUR SOUTH, EXTENDING ACROSS PORTIONS OF
VIRGINIA AND PERHAPS INTO THE CAROLINAS. A DRIER STRETCH OF WEATHER
IS EXPECTED FOR MUCH OF THE FORECAST AREA FROM SATURDAY NIGHT
THROUGH MONDAY, AS THE FRONTAL BOUNDARY IS PROGGED TO REMAIN OFF TO
OUR SOUTH WITH WEAK HIGH PRESSURE TO THE WEST INFLUENCING OUR
REGION. A FEW SHORTWAVES/VORT MAXES ARE FORECAST TO PASS THROUGH THE
MID-LEVEL FLOW DURING THIS TIMEFRAME, SO SOME ISOLATED SHWRS/TSTORMS
CANNOT BE COMPLETELY RULED OUT. OUR SOUTHERN ZONES WOULD BE THE MOST
PROBABLE AREA FOR THIS ACTIVITY, WITH THE STALLED FRONT OFF TO THE
SOUTH. FOR NOW, WE WILL KEEP LOW POPS IN PLACE, WITH THE BEST
POTENTIAL FOR ISOLATED TO SCATTERED SHWRS/TSTORMS BEING ON MONDAY AS
THE MODELS SHOW A WAVE OF LOW PRESSURE DEVELOPING ALONG THE STALLED
BOUNDARY.
FOR TUESDAY, BOTH THE GFS AND ECMWF SHOW POSSIBLE LOW PRESSURE AND
ANOTHER COLD FRONT APPROACHING FROM THE WEST AND TRACKING THROUGH
OUR AREA. WHILE THERE ARE SOME TIMING DIFFERENCES BETWEEN THE MODELS
WITH THE EASTWARD PROGRESSION OF THE FRONT ON TUESDAY, THIS DOES
LOOK TO BE THE BEST OPPORTUNITY FOR MORE WIDESPREAD SCATTERED
CONVECTIVE ACTIVITY ACROSS THE FORECAST AREA, AND HIGH CHANCE POPS
ARE IN PLACE. THEREAFTER, A QUIETER STRETCH OF WEATHER IS EXPECTED
FOR THE REST OF THE WORK WEEK AS THE COLD FRONT PROGRESSES EAST AND
OFFSHORE EARLY WEDNESDAY, WITH HIGH PRESSURE FROM AROUND THE GREAT
LAKES REGION BUILDING TOWARD THE MID ATLANTIC. DAYTIME TEMPERATURES
IN THE WEDNESDAY THROUGH FRIDAY TIMEFRAME ARE EXPECTED TO BE A
LITTLE BELOW AVERAGE FOR MID-AUGUST, WITH HIGHS RANGING FROM THE
MIDDLE 70S TO THE LOWER 80S.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
18Z TAFS WILL CARRY THUNDERSTORMS ALL TERMINALS, BUT THEN
GENERALLY BETTER FLYING CONDITIONS ARE EXPECTED FROM THIS EVENING
ONWARD.
WE HAVE TEMPORARY MVFR CONDITIONS DURING THUNDERSTORMS FOR THE REST
OF THIS AFTERNOON AND VFR CONDITIONS BETWEEN. THERE COULD BE ONE OR
TWO BANDS OF THUNDER. SOUTHWEST WINDS WILL AVERAGE 10 TO 15 KNOTS
WITH SOME GUSTS TO AROUND 20 KNOTS. STRONGER GUSTS IN THUNDER ARE
POSSIBLE AT THE SOUTHEASTERN TERMINALS AND AIRPORTS.
FOR LATE THIS AFTERNOON AND EARLY EVENING, SOME SHOWERS MIGHT
LINGER, BUT BELIEVE THE IMPACT SHOULD BE MINIMAL WITH GENERALLY
VFR CONDITIONS. WINDS SHOULD VEER SLIGHTLY MORE TO THE WEST AND
WE DID DROP THE GUSTINESS.
OVERNIGHT, WE EXPECT THE CFP WITH VFR DEBRIS MID AND HIGH LEVEL
CLOUDS. WINDS WILL BECOME NORTHWEST AT 5 TO 10 KNOTS. WITH DRIER
AIR MOVING IN, GUIDANCE AND OUR TAFS ARE NOT CARRYING FOG.
SOMETIMES GUIDANCE GETS TOO BULLISH WITH THE MIXING ON SUMMER
NIGHTS AND WE WILL REVISIT. THE LEAST CONFIDENCE ABOUT LACK OF FOG
IS AT RURAL AND MORE OUTLYING TERMINALS.
THEN ON SATURDAY MORNING, NOT MUCH CHANGE IN SKY CONDITIONS OR
WINDS EXPECTED. SO THE LAST FORECAST PERIOD IN THE CURRENT TAF
SHOULD HOLD FOR THE TERMINALS THROUGH THE MORNING.
A SEA BREEZE FRONT MIGHT FORM SATURDAY AFTERNOON FOR NOW EXPECTED
BEYOND THE END OF THE CURRENT TAF CYCLE AND NOT REACHING KPHL BY 00Z.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY...MAINLY VFR CONDITIONS. ISOLATED
SHWRS/TSTORMS REMAIN POSSIBLE, ESPECIALLY MONDAY.
TUESDAY...VFR TO POSSIBLE MVFR AT TIMES WITH SCATTERED SHWRS/TSTORMS
POSSIBLE. LIGHT SOUTHERLY WINDS EARLY BECOME WEST-NORTHWEST LATER
TUESDAY EVE/NIGHT.
WEDNESDAY...VFR CONDITIONS EXPECTED WITH LIGHT WINDS.
&&
.MARINE...
WE WILL CONTINUE THE SCA NORTHERN WATERS INTO THIS EVENING. THE
ENTRANCE TO NEW YORK HARBOR BUOY`S SEAS HAVE RISEN TO AROUND 4 FEET
AND WITH THE CONTINUED SOUTHERLY FLOW INTO EARLY THIS EVENING, WE
MIGHT MEET THE SEAS CRITERIA. MEANWHILE THE DELAWARE BAY BUOY`S SEAS
CONTINUE TO VERIFY BELOW WAVE WATCH GUIDANCE AND THEIR WINDOW OF
OPPORTUNITY FOR SMALL CRAFT ADVISORY CONDITIONS IS CLOSING FAST.
ONCE THE FRONT CLEARS, THE WESTERLY FLOW BEHIND IT IS NOT THAT
STRONG AND SUB SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED THROUGH
SATURDAY. A SEA BREEZE FRONT SHOULD FORM ON SATURDAY AFTERNOON.
OUTLOOK...
FROM SATURDAY NIGHT THROUGH MONDAY, A FRONTAL BOUNDARY WILL REMAIN
STALLED TO THE SOUTH OF OUR FORECAST AREA AND ADJACENT COASTAL
WATERS. WINDS AND SEAS THROUGH THIS TIMEFRAME ARE EXPECTED TO BE AT
SUB-SCA LEVELS, WITH SEAS IN THE 2 TO 3 FOOT RANGE AND WINDS AT
15 KNOTS OR LESS. A COLD FRONT IS FORECAST TO CROSS THE AREA
TUESDAY, BRINGING A BETTER CHANCE FOR SCATTERED SHWRS/TSTORMS,
FOLLOWED BY HIGH PRESSURE BUILDING ACROSS THE REGION AND COASTAL
WATERS DURING WEDNESDAY. CONDITIONS ON OUR AREA WATERS ARE EXPECTED
TO REMAIN AT SUB-ADVISORY LEVELS THROUGH TUESDAY AND WEDNESDAY.
&&
.HYDROLOGY...
FLASH FLOOD WATCH CONTINUES FOR NORTHERN COUNTIES. UP TO 4 INCHES OF
RAIN HAS FALLEN OVERNIGHT LEAVING THIS AREA MORE SUSCEPTIBLE TO
FLOODING TODAY. ELSEWHERE WHILE THERE IS A LOWER CHANCE, ITS NOT A
ZERO CHANCE, BUT THE MESOSCALE MODELS CONTINUE TO SHOW FAIRLY
PROGRESSIVE STORMS, SO UNLESS THERE IS TRAINING, THE RISK STILL
APPEARS LOWER THAN LOCATIONS THAT HAVE BEEN ALREADY DOUSED THE PAST
24 HOURS.
&&
.RIP CURRENTS...
A MODERATE RISK FOR THE FORMATION OF RIP CURRENTS CONTINUES
THROUGH THIS EVENING ALONG THE NEW JERSEY COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ054-055-
061-062.
NJ...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR NJZ001-
007>010.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ450-
451.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...KLINE
AVIATION...GIGI/KLINE
MARINE...GIGI/KLINE
HYDROLOGY...GIGI
RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
110 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH FROM THE WEST THIS AFTERNOON AND
MOVE THROUGH THE REGION BY EARLY SATURDAY. THIS FRONT WILL THEN
STALL TO OUR SOUTH THROUGH MONDAY. A FEW WAVES OF LOW PRESSURE MAY
MOVE ALONG THIS BOUNDARY FOR THE EARLY PART OF THE WEEK. ANOTHER
COLD FRONT WILL CROSS THE REGION FROM THE WEST AROUND TUESDAY,
FOLLOWED BY AN AREA OF HIGH PRESSURE FOR WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SPC HRW WRF-ARW IS VERIFYING THE BEST OF THE MESOSCALE MODELS THIS
MORNING AND WAS USED AS A BACK END TIMING OF HIGHER POPS. ON THE
FRONT SIDE, THE HRRR GETS VIGOROUS RATHER QUICKLY WHICH GIVEN WE
ARE NEARING THE CONVECTIVE TEMP CAN NOT BE DISCOUNTED. THE
OPERATIVE WORD FROM HERE ON OUT IS THAT ALL OF THE MESOSCALE MODEL
PROGRESSIONS EVEN IF NOT GEOGRAPHICALLY CORRECT ARE OF DECENT
MOVEMENT. THIS WOULD REDUCE THE FLASH FLOOD THREAT IN PLACES THAT
WERE NOT DOUSED THIS MORNING. OTHERWISE, NO BIG CHANGES TO THE
CONVECTIVE CONCERNS. THE MID LEVEL LAPSE RATES ARE NOT IMPRESSIVE
AND WARMER AIR CONTINUES TO MOVE IN AT 700MB AND 500MB. THERE MAY
BE A WINDOW SERN CWA BECAUSE OF THE CAPPING WHERE THE INITIAL
RELEASE MIGHT PRODUCE VIGOROUS ENOUGH UPDRAFTS TO CAUSE
THUNDERSTORMS TO POSSIBLY REACH SEVERE LIMITS. LESS LIKELY NORTH
AND WEST OF I95 WHERE CONVECTION SHOULD BE RAMPING UPWARD PRETTY
QUICKLY.
BASED ON CURRENT TEMPS AND SUNSHINE, WE NUDGED MAX TEMPS UP
SLIGHTLY AGAIN SERN PART OF OUR CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
THE FRONT WILL CONTINUE CROSSING THE AREA TONIGHT. POPS DECREASE
FROM NORTH TO SOUTH AND THE NIGHT PROGRESSES. WINDS SHIFT TO WRLY
THEN NWRLY OVERNIGHT AND DRIER AIR BEGINS TO ARRIVE OVER THE AREA.
IT MAY TAKE UNTIL AFTER DAWN SAT TO BEGIN MIXING THE DRIER AIR DOWN.
OVERNIGHT LOW TEMPS TONIGHT WILL RANGE FROM THE LOW 60S ACROSS THE
NORTH TO THE LOW 70S OVER THE SOUTH...WHERE THE FRONT WILL CROSS
LATE.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AT THE START OF THE EXTENDD PD, THE AFOREMENTIONED CDFNT WILL BE
OFF THE CST AND ALL OF THE MDL GUID IS IN REASONABLE AGREEMENT
THAT SAT SHOULD BE MOSTLY IF NOT ALL DRY. IF THERE IS TO BE ANY
LINGERING PRECIP, IT WILL BE EARLY AND ACRS THE S. FOR NOW, WILL
JUST KEEP SOME VERY LOW POPS ACRS SRN AREAS EARLY AND THIS COULD
END UP BEING OVERDONE.
HIGH PRESSURE THEN BUILD IN BEHIND THE FRONT, WHICH WILL REMAIN
STALLED S OF THE REGION AND SUNDAY LOOKS PREDOMINANTLY DRY AS
WELL. SOME OF THE GUID IS INDICATING SOME POPS OVER THE EXTREME
SRN AREAS, WHILE OTHER GUID KEEPS THE POPS S OF THE CWA. SINCE THE
GFS (THE GUID WITH THE MOST NWD EXTENT) OFTEN OVERDOES ITS PRECIP
FIELD, AM INCLINED TO GO WITH THE OTHER SOLNS ATTM, BUT MAY NEED
TO INCREASE POPS LATER ON SUN ACRS THE S IF OTHER GUID COMES INTO
AGREEMENT.
BY MON, BOTH THE ECMWF AND GFS WANT TO BRING A WEAK LOW TO THE S
AND AGAIN ITS A QUESTION OF HOW FAR N ANY PRECIP WOULD COME. ONCE
AGAIN, THE GFS HAS A FURTHER N EXTENT, BUT BOTH MDLS INDICATE A
STRONGER LOW, SO HAVE BOUGHT OFF ON A MORE NRN EXTENT THIS TIME
AND BROUGHT SOME LOW POPS EVERYWHERE, BUT THIS IS LOW CONFIDENCE.
BY TUE, A CDFNT WILL BE APPROACHING FROM THE W AND WILL CROSS THE
REGION BY TUE NIGHT. THIS LOOKS TO BE OUR BEST CHC OF RAIN.
BEHIND THE CFP, HIGH PRESSURE WILL BUILD DOWN FROM THE NRN PLAINS
AND BRING DRY WX FOR WED AND THU.
TEMPS LOOK TO BE AT OR SLIGHTLY ABOVE NRML THRU MIDWEEK AND THEN
WILL BE A TAD BELOW NRML BEHIND THE TUE FROPA AS THE HIGH BUILDS
IN, DEW POINTS WILL BE QUITE PLEASANT FOR MID AUGUST THOUGH.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
18Z TAFS WILL CARRY THUNDERSTORMS ALL TERMINALS, BUT THEN
GENERALLY BETTER FLYING CONDITIONS ARE EXPECTED FROM THIS EVENING
ONWARD.
EXCEPT FOR KACY AND KMIV (WHICH START AT 19Z), WE WILL START THE
TAFS WITH TEMPORARY MVFR CONDITIONS DURING THUNDERSTORMS AND VFR
CONDITIONS BETWEEN. THERE COULD BE ONE OR TWO BANDS OF THUNDER.
SOUTHWEST WINDS WILL AVERAGE 10 TO 15 KNOTS WITH SOME GUSTS TO
AROUND 20 KNOTS. STRONGER GUSTS IN THUNDER ARE POSSIBLE AT THE
SOUTHEASTERN TERMINALS AND AIRPORTS.
FOR LATE THIS AFTERNOON AND EARLY EVENING, SOME SHOWERS MIGHT
LINGER, BUT BELIEVE THE IMPACT SHOULD BE MINIMAL WITH GENERALLY
VFR CONDITIONS. WINDS SHOULD VEER SLIGHTLY MORE TO THE WEST AND
WE DID DROP THE GUSTINESS.
OVERNIGHT, WE EXPECT THE CFP WITH VFR DEBRIS MID AND HIGH LEVEL
CLOUDS. WINDS WILL BECOME NORTHWEST AT 5 TO 10 KNOTS. WITH DRIER
AIR MOVING IN, GUIDANCE AND OUR TAFS ARE NOT CARRYING FOG.
SOMETIMES GUIDANCE GETS TOO BULLISH WITH THE MIXING ON SUMMER
NIGHTS AND WE WILL REVISIT. THE LEAST CONFIDENCE ABOUT LACK OF FOG
IS AT RURAL AND MORE OUTLYING TERMINALS.
THEN ON SATURDAY MORNING, NOT MUCH CHANGE IN SKY CONDITIONS OR
WINDS EXPECTED. SO THE LAST FORECAST PERIOD IN THE CURRENT TAF
SHOULD HOLD FOR THE TERMINALS THROUGH THE MORNING.
OUTLOOK...
SAT NGT THROUGH MON...THERE COULD BE SOME LINGERING LOWER CIGS
EARLY SAT, ESPECIALLY ACRS THE S, OTHERWISE...MAINLY VFR
CONDITIONS EXPECTED. ISOLATED SHWRS/TSTMS REMAIN POSSIBLE,
ESPECIALLY MONDAY. HIGH CONFIDENCE.
TUES...VFR TO POSSIBLE MVFR AT TIMES WITH SCATTERED SHWRS/TSTMS
POSSIBLE AS CDFNT CROSSES THE REGION FROM W TO E. WNDSHFT WITH
CFP. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
WINDS AND SEAS WILL SLOWLY BUILD TODAY AS THE LOW PRESSURE SYSTEM TO
THE NORTH AND ITS ATTACHED FRONT BEGIN TO MOVE TOWARD THE AREA. IT
APPEARS THAT THERE WILL BE A WEAK INVERSION IN PLACE TODAY...BUT
PROBABLY ENOUGH MIXING TO ALLOW SOME OF THE LOW LEVEL WINDS (AROUND
30 KTS) TO CREATE SOME GUSTS ACROSS THE NRN COASTAL WATERS. SEAS
ACROSS THESE AREAS MAY BUILD TO 5 FT...SO WE WILL RAISE THE SCA FLAG
FOR THE 12Z TO 00Z PERIOD TO COVER THESE ENHANCED CONDITIONS. SCT
SHOWERS/TSTMS EXPECTED ON ALL WATERS TODAY WITH LOCALLY HIGHER
WINDS/SEAS. TONIGHT...THE COLD FRONT WILL CROSS THROUGH WITH SCAT
SHOWERS/TSTMS EARLY THEN IMPROVING CONDITIONS. WINDS SHIFT TO WRLY
TONIGHT THEN NW BY MORNING.
OUTLOOK...
A COLD FRONT WILL BE TRACKING ACROSS THE CSTL WATERS, EVENTUALLY
STALLING TO OUR SOUTH THROUGH MON. SEAS ARE EXPECTED TO GENL BE IN
THE 2 TO 3 FT RANGE WITH SUSTAINED WINDS GENLY UNDER 10 KT AND
GUSTS UNDER 15 KT, SO SUB-ADVISORY CONDS ARE EXPECTED THRU THE PD.
&&
.HYDROLOGY...
FLASH FLOOD WATCH FOR NORTHERN COUNTIES. UP TO 4 INCHES OF RAIN HAS
FALLEN OVERNIGHT LEAVING THIS AREA MORE SUSCEPTIBLE TO FLOODING
TODAY. ELSEWHERE WHILE THERE IS A LOWER CHANCE, ITS NOT A ZERO
CHANCE, BUT THE MESOSCALE MODELS CONTINUE TO SHOW FAIRLY PROGRESSIVE
STORMS, SO UNLESS THERE IS TRAINING, THE RISK STILL APPEARS LOWER
THAN LOCATIONS THAT HAVE BEEN ALREADY DOUSED THE PAST 24 HOURS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ054-055-
061-062.
NJ...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR NJZ001-
007>010.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ450-
451.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...GIGI/NIERENBERG
MARINE...NIERENBERG/O`HARA
HYDROLOGY...GIGI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1200 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH FROM THE WEST THIS AFTERNOON AND
MOVE THROUGH THE REGION BY EARLY SATURDAY. THIS FRONT WILL THEN
STALL TO OUR SOUTH THROUGH MONDAY. A FEW WAVES OF LOW PRESSURE MAY
MOVE ALONG THIS BOUNDARY FOR THE EARLY PART OF THE WEEK. ANOTHER
COLD FRONT WILL CROSS THE REGION FROM THE WEST AROUND TUESDAY,
FOLLOWED BY AN AREA OF HIGH PRESSURE FOR WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SPC HRW WRF-ARW IS VERIFYING THE BEST OF THE MESOSCALE MODELS THIS
MORNING AND WAS USED AS A BACK END TIMING OF HIGHER POPS. ON THE
FRONT SIDE, THE HRRR GETS VIGOROUS RATHER QUICKLY WHICH GIVEN WE
ARE NEARING THE CONVECTIVE TEMP CAN NOT BE DISCOUNTED. THE
OPERATIVE WORD FROM HERE ON OUT IS THAT ALL OF THE MESOSCALE MODEL
PROGRESSIONS EVEN IF NOT GEOGRAPHICALLY CORRECT ARE OF DECENT
MOVEMENT. THIS WOULD REDUCE THE FLASH FLOOD THREAT IN PLACES THAT
WERE NOT DOUSED THIS MORNING. OTHERWISE, NO BIG CHANGES TO THE
CONVECTIVE CONCERNS. THE MID LEVEL LAPSE RATES ARE NOT IMPRESSIVE
AND WARMER AIR CONTINUES TO MOVE IN AT 700MB AND 500MB. THERE MAY
BE A WINDOW SERN CWA BECAUSE OF THE CAPPING WHERE THE INITIAL
RELEASE MIGHT PRODUCE VIGOROUS ENOUGH UPDRAFTS TO CAUSE
THUNDERSTORMS TO POSSIBLY REACH SEVERE LIMITS. LESS LIKELY NORTH
AND WEST OF I95 WHERE CONVECTION SHOULD BE RAMPING UPWARD PRETTY
QUICKLY.
BASED ON CURRENT TEMPS AND SUNSHINE, WE NUDGED MAX TEMPS UP
SLIGHTLY AGAIN SERN PART OF OUR CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
THE FRONT WILL CONTINUE CROSSING THE AREA TONIGHT. POPS DECREASE
FROM NORTH TO SOUTH AND THE NIGHT PROGRESSES. WINDS SHIFT TO WRLY
THEN NWRLY OVERNIGHT AND DRIER AIR BEGINS TO ARRIVE OVER THE AREA.
IT MAY TAKE UNTIL AFTER DAWN SAT TO BEGIN MIXING THE DRIER AIR DOWN.
OVERNIGHT LOW TEMPS TONIGHT WILL RANGE FROM THE LOW 60S ACROSS THE
NORTH TO THE LOW 70S OVER THE SOUTH...WHERE THE FRONT WILL CROSS
LATE.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AT THE START OF THE EXTENDD PD, THE AFOREMENTIONED CDFNT WILL BE
OFF THE CST AND ALL OF THE MDL GUID IS IN REASONABLE AGREEMENT
THAT SAT SHOULD BE MOSTLY IF NOT ALL DRY. IF THERE IS TO BE ANY
LINGERING PRECIP, IT WILL BE EARLY AND ACRS THE S. FOR NOW, WILL
JUST KEEP SOME VERY LOW POPS ACRS SRN AREAS EARLY AND THIS COULD
END UP BEING OVERDONE.
HIGH PRESSURE THEN BUILD IN BEHIND THE FRONT, WHICH WILL REMAIN
STALLED S OF THE REGION AND SUNDAY LOOKS PREDOMINANTLY DRY AS
WELL. SOME OF THE GUID IS INDICATING SOME POPS OVER THE EXTREME
SRN AREAS, WHILE OTHER GUID KEEPS THE POPS S OF THE CWA. SINCE THE
GFS (THE GUID WITH THE MOST NWD EXTENT) OFTEN OVERDOES ITS PRECIP
FIELD, AM INCLINED TO GO WITH THE OTHER SOLNS ATTM, BUT MAY NEED
TO INCREASE POPS LATER ON SUN ACRS THE S IF OTHER GUID COMES INTO
AGREEMENT.
BY MON, BOTH THE ECMWF AND GFS WANT TO BRING A WEAK LOW TO THE S
AND AGAIN ITS A QUESTION OF HOW FAR N ANY PRECIP WOULD COME. ONCE
AGAIN, THE GFS HAS A FURTHER N EXTENT, BUT BOTH MDLS INDICATE A
STRONGER LOW, SO HAVE BOUGHT OFF ON A MORE NRN EXTENT THIS TIME
AND BROUGHT SOME LOW POPS EVERYWHERE, BUT THIS IS LOW CONFIDENCE.
BY TUE, A CDFNT WILL BE APPROACHING FROM THE W AND WILL CROSS THE
REGION BY TUE NIGHT. THIS LOOKS TO BE OUR BEST CHC OF RAIN.
BEHIND THE CFP, HIGH PRESSURE WILL BUILD DOWN FROM THE NRN PLAINS
AND BRING DRY WX FOR WED AND THU.
TEMPS LOOK TO BE AT OR SLIGHTLY ABOVE NRML THRU MIDWEEK AND THEN
WILL BE A TAD BELOW NRML BEHIND THE TUE FROPA AS THE HIGH BUILDS
IN, DEW POINTS WILL BE QUITE PLEASANT FOR MID AUGUST THOUGH.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
PLENTY OF MVFR/IFR CONDITIONS ACROSS THE TERMINALS EARLY THIS
MORNING. THE SOUTHERLY FLOW OF HUMID AIR AND SEVERAL WEAK S/W MOVING
THROUGH THE FLOW WILL KEEP PLENTY OF SHOWERS ACROSS THE REGION TODAY
WITH THE AREAS NORTH/WEST BEING FAVORED EARLY AND THEN THE DEL
VALLEY AND SRN AREAS LATER THIS AFTERNOON. TSTMS ARE ALSO EXPECTED
MOSTLY THIS AFTERNOON AND EARLY EVENING. A COLD FRONT WILL CROSS THE
AREA LATER TODAY AND TONIGHT WITH IMPROVING CONDITIONS ARRIVING
BEHIND IT FRI NIGHT.
MOST MODELS ARE INDICATING ONE BATCH OF SHOWERS EARLY THIS MORNING
ACROSS THE NORTH...THEN MORE DURING THE MORNING NORTH/CENTRAL
FOLLOWED BY A BREAK THIS AFTERNOON...THEN MORE SCT TSTMS LATER THIS
AFTERNOON AND EVENING WITH THE FRONT. WE HAVE BLENDED THIS IN WITH
SOME INPUT FROM THE EARLIER TAFS TO ARRIVE AT A LOW-MOD CONFID FCST.
OUTLOOK...
SAT THROUGH MON...THERE COULD BE SOME LINGERING LOWER CIGS EARLY
SAT, ESPECIALLY ACRS THE S, OTHERWISE...MAINLY VFR CONDITIONS
EXPECTED. ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MONDAY.
HIGH CONFIDENCE.
TUES...VFR TO POSSIBLE MVFR AT TIMES WITH SCATTERED SHWRS/TSTMS
POSSIBLE AS CDFNT CROSSES THE REGION FROM W TO E. WNDSHFT WITH
CFP. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
WINDS AND SEAS WILL SLOWLY BUILD TODAY AS THE LOW PRESSURE SYSTEM TO
THE NORTH AND ITS ATTACHED FRONT BEGIN TO MOVE TOWARD THE AREA. IT
APPEARS THAT THERE WILL BE A WEAK INVERSION IN PLACE TODAY...BUT
PROBABLY ENOUGH MIXING TO ALLOW SOME OF THE LOW LEVEL WINDS (AROUND
30 KTS) TO CREATE SOME GUSTS ACROSS THE NRN COASTAL WATERS. SEAS
ACROSS THESE AREAS MAY BUILD TO 5 FT...SO WE WILL RAISE THE SCA FLAG
FOR THE 12Z TO 00Z PERIOD TO COVER THESE ENHANCED CONDITIONS. SCT
SHOWERS/TSTMS EXPECTED ON ALL WATERS TODAY WITH LOCALLY HIGHER
WINDS/SEAS. TONIGHT...THE COLD FRONT WILL CROSS THROUGH WITH SCAT
SHOWERS/TSTMS EARLY THEN IMPROVING CONDITIONS. WINDS SHIFT TO WRLY
TONIGHT THEN NW BY MORNING.
OUTLOOK...
A COLD FRONT WILL BE TRACKING ACROSS THE CSTL WATERS, EVENTUALLY
STALLING TO OUR SOUTH THROUGH MON. SEAS ARE EXPECTED TO GENL BE IN
THE 2 TO 3 FT RANGE WITH SUSTAINED WINDS GENLY UNDER 10 KT AND
GUSTS UNDER 15 KT, SO SUB-ADVISORY CONDS ARE EXPECTED THRU THE PD.
&&
.HYDROLOGY...
FLASH FLOOD WATCH FOR NORTHERN COUNTIES. UP TO 4 INCHES OF RAIN HAS
FALLEN OVERNIGHT LEAVING THIS AREA MORE SUSCEPTIBLE TO FLOODING
TODAY. ELSEWHERE WHILE THERE IS A LOWER CHANCE, ITS NOT A ZERO
CHANCE, BUT THE MESOSCALE MODELS CONTINUE TO SHOW FAIRLY PROGRESSIVE
STORMS, SO UNLESS THERE IS TRAINING, THE RISK STILL APPEARS LOWER
THAN LOCATIONS THAT HAVE BEEN ALREADY DOUSED THE PAST 24 HOURS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ054-055-
061-062.
NJ...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR NJZ001-
007>010.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ450-
451.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
930 PM EDT SAT AUG 10 2013
.UPDATE (REST OF TONIGHT AND SUNDAY)...
01Z WATER VAPOR AND H4 RAP ANALYSIS SHOW UPPER LEVEL RIDGING
BUILDING OVER THE FLORIDA PENINSULA IN THE WAKE OF A DEPARTING TUTT
CELL...NOW WELL TO OUR WEST. WHILE THE BUILDING RIDGE DID NOT REALLY
DRY THE ATMOSPHERE OUT ALL THAT MUCH OVER OUR AREA TODAY...WE DID
SEE A JUMP IN THE MID-LEVEL TEMPERATURES BETWEEN 800-600MB. THIS
INCREASE IN TEMPS CREATED A CAPPING ENVIRONMENT THAT HELD BACK JUST
ABOUT ALL THE EXPECTED CONVECTION TODAY. WAS ONLY ABLE TO BRIEFLY
GROW A FEW ISOLATED CELLS...WHICH QUICKLY COLLAPSED.
JUST ABOUT AS QUICK AN EVENING AS WE SEE AROUND THESE PARTS IN
AUGUST ONGOING OUT THERE. RADAR IS ESSENTIALLY VOID OF CONVECTIVE
ECHOES AND SEE LITTLE REASON TO EXPECT ANYTHING SUBSTANTIAL TO
DEVELOP THROUGH THE REMAINDER OF THE EVENING. HAVE REMOVED ALL POPS
FROM THE FORECAST FOR THE REST OF THE OVERNIGHT.
ANOTHER QUIET...BUT HOT DAY ON TAP FOR THE SECOND HALF OF THE
WEEKEND. UPPER RIDGE AND IT ENHANCED SYNOPTIC SUPPRESSION WILL
CONTINUE TO WARM THE COLUMN AND DRY IT OUT. CURRENT FORECAST ONLY
HAS A 20% CHANCE FOR ISOLATED STORMS SUNDAY AFTERNOON AND FEEL THIS
IS STILL ON TRACK. IN FACT...IF TODAY AS ANY SIGN OF THINGS TO
COME...THEN 20% MAY BE A BIT ON THE HIGH SIDE. HOWEVER...CAN NEVER
RULE OUT THAT ISOLATED CELL ALONG THE SEA-BREEZE THIS TIME OF
YEAR...SO WILL KEEP THIS SLIGHT CHANCE IN THE FORECAST FOR NOW. WITH
THE SYNOPTIC SUPPRESSION IN PLACE AND ONLY A SCT CU FIELD FOR MOST
SPOTS...TEMPS WILL EASILY CLIMB INTO THE MIDDLE 90S FOR MOST SPOTS
AWAY FROM THE IMMEDIATE COAST...WITH A FEW SPOTS LIKELY JUMPING
BRIEFLY INTO THE UPPER 90S. ENJOY THE REST OF YOUR NIGHT.
&&
.AVIATION...
DRIER AIR HAS MOVED INTO THE PICTURE CREATING AN UNUSUAL SCENARIO
WITH CLEAR SKIES TONIGHT AND ONLY ISOLATED SHOWERS WITH A REMOTE
CHANCE FOR A THUNDERSTORM SUNDAY.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH THE
REMAINDER OF THE WEEKEND AND MUCH OF THE UPCOMING WORK WEEK. WINDS
AND SEAS ARE EXPECTED TO REMAIN BELOW HEADLINE THRESHOLDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 77 93 78 93 / 00 20 20 30
FMY 77 94 75 94 / 00 20 20 20
GIF 75 96 75 94 / 00 10 10 20
SRQ 75 93 76 93 / 00 20 20 20
BKV 73 96 72 95 / 00 20 20 30
SPG 79 93 81 93 / 00 20 20 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...PAXTON
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1012 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED IN THE ATLANTIC WILL DIRECT A MOIST
ONSHORE FLOW INTO THE FORECAST AREA. A SLOW MOVING FRONTAL
SYSTEM WILL REMAIN NORTHWEST OF THE AREA THROUGH SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...HIGH PRESSURE CENTERED OFFSHORE WILL CIRCULATE
MOIST AIR INTO THE FORECAST AREA. THIS MOISTURE PLUS HEATING
SHOULD HELP SUPPORT SHOWERS AND THUNDERSTORMS BUT EXPECT LIMITED
COVERAGE BECAUSE OF UPPER-LEVEL RIDGING AND SLOW MOVEMENT. LEANED
TOWARD THE MORE CONSISTENT GFS MOS POPS WHICH WERE MUCH LOWER THAN
THE NAM MOS POPS. THE HIGH-RESOLUTION MODELS DISPLAYED MAINLY
SCATTERED COVERAGE BUT THE 03Z HRRR DID APPEAR TO INDICATE
ENHANCED COVERAGE IN A BAND FROM AUGUSTA TO COLUMBIA THIS
AFTERNOON. THIS MAY BE ASSOCIATED WITH THE WEAK H7 SHORTWAVE
TROUGH CAUGHT IN THE RIDGE OVER THE FORECAST AREA SHOWN BY THE
LATEST RAP. VERY HEAVY RAIN WILL BE POSSIBLE WITH ANY
THUNDERSTORMS BECAUSE OF PRECIPITABLE WATER A LITTLE OVER 2 INCHES
AND SLOW STORM MOVEMENT. LEANED TOWARD THE WARMER GFS MOS
TEMPERATURES BASED ON YESTERDAY/S VERIFICATION.
TONIGHT...EVEN WITH HIGH MOISTURE LEVELS WITH PW VALUES NEAR 2 INCHES
EXPECT RAIN CHANCES TO DECREASE TO ABOUT 20 PERCENT WITH THE LOSS OF
DAYTIME HEATING. WARM AND MUGGY WITH LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
THE MODELS CONTINUE TO SHOW A MOIST SOUTHERLY FLOW ASSOCIATED
WITH THE OFFSHORE HIGH WITH THE FRONTAL SYSTEM REMAINING NORTH OF
THE AREA. THE MOIST FLOW SUPPORTS SHOWERS AND THUNDERSTORMS BUT
STILL EXPECT LIMITED COVERAGE BECAUSE OF UPPER RIDGING AND SLOW
STORM MOVEMENT. MOST OF THE MOS GUIDANCE INDICATED JUST CHANCE
POPS. PRECIPITABLE WATER AROUND 2 INCHES PLUS SLOW STORM MOVEMENT
SUPPORTS POSSIBLE VERY HEAVY RAIN WITH ANY THUNDERSTORMS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS AND ECMWF DISPLAY A FRONT NEAR THE FORECAST AREA THROUGH THE
MEDIUM-RANGE PERIOD. THE MODELS SHOW FLAT UPPER RIDGING EARLY
WITH TROUGHING BEGINNING TUESDAY. THIS PATTERN SUPPORTS POPS ABOVE
CLIMATOLOGY. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING ALONG
THE EAST-WEST ORIENTED FRONT MAY LEAD VERY HEAVY RAINFALL DURING
PART OF THE PERIOD.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
MVFR/IFR STRATUS MOVING INTO THE AREA THIS MORNING WHICH WILL
PERSIST UNTIL AROUND 15Z DUE TO A MOIST SOUTHEAST LOW LEVEL FLOW.
VFR CONDITIONS EXPECTED TO RETURN AFTER 14Z AS BOUNDARY LAYER
MIXING TAKES HOLD. SCATTERED CONVECTION POSSIBLE THIS AFTERNOON
INTO EARLY THIS EVENING BUT COVERAGE TOO LIMITED TO INCLUDE IN
TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN AFTERNOON
CONVECTION AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
647 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED IN THE ATLANTIC WILL DIRECT A MOIST
ONSHORE FLOW INTO THE FORECAST AREA. A SLOW MOVING FRONTAL
SYSTEM WILL REMAIN NORTHWEST OF THE AREA THROUGH SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE CENTERED OFFSHORE WILL CIRCULATE MOIST AIR INTO THE
FORECAST AREA. THIS MOISTURE PLUS HEATING SHOULD HELP SUPPORT
SHOWERS AND THUNDERSTORMS BUT EXPECT LIMITED COVERAGE BECAUSE OF
UPPER-LEVEL RIDGING AND SLOW MOVEMENT. LEANED TOWARD THE MORE
CONSISTENT GFS MOS POPS WHICH WERE MUCH LOWER THAN THE NAM MOS
POPS. THE HIGH-RESOLUTION MODELS DISPLAYED MAINLY SCATTERED
COVERAGE BUT THE 03Z HRRR DID APPEAR TO INDICATE ENHANCED
COVERAGE IN A BAND FROM AUGUSTA TO COLUMBIA THIS AFTERNOON. THIS MAY
BE ASSOCIATED WITH THE WEAK H7 SHORTWAVE TROUGH CAUGHT IN THE
RIDGE OVER THE FORECAST AREA SHOWN BY THE LATEST RAP. VERY HEAVY
RAIN WILL BE POSSIBLE WITH ANY THUNDERSTORMS BECAUSE OF
PRECIPITABLE WATER A LITTLE OVER 2 INCHES AND SLOW STORM MOVEMENT.
LEANED TOWARD THE WARMER GFS MOS TEMPERATURES BASED ON YESTERDAY/S
VERIFICATION.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THE MODELS CONTINUE TO SHOW A MOIST SOUTHERLY FLOW ASSOCIATED
WITH THE OFFSHORE HIGH WITH THE FRONTAL SYSTEM REMAINING NORTH OF
THE AREA. THE MOIST FLOW SUPPORTS SHOWERS AND THUNDERSTORMS BUT
STILL EXPECT LIMITED COVERAGE BECAUSE OF UPPER RIDGING AND SLOW
STORM MOVEMENT. MOST OF THE MOS GUIDANCE INDICATED JUST CHANCE
POPS. PRECIPITABLE WATER AROUND 2 INCHES PLUS SLOW STORM MOVEMENT
SUPPORTS POSSIBLE VERY HEAVY RAIN WITH ANY THUNDERSTORMS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS AND ECMWF DISPLAY A FRONT NEAR THE FORECAST AREA THROUGH THE
MEDIUM-RANGE PERIOD. THE MODELS SHOW FLAT UPPER RIDGING EARLY
WITH TROUGHING BEGINNING TUESDAY. THIS PATTERN SUPPORTS POPS ABOVE
CLIMATOLOGY. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING ALONG
THE EAST-WEST ORIENTED FRONT MAY LEAD VERY HEAVY RAINFALL DURING
PART OF THE PERIOD.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
MVFR/IFR STRATUS MOVING INTO THE AREA EARLY THIS MORNING WHICH WILL
PERSIST UNTIL AROUND 14Z DUE TO A MOIST SOUTHEAST LOW LEVEL FLOW.
VFR CONDITIONS EXPECTED TO RETURN AFTER 14Z AS BOUNDARY LAYER MIXING
TAKES HOLD. SCATTERED CONVECTION POSSIBLE THIS AFTERNOON INTO EARLY
THIS EVENING BUT COVERAGE TOO LIMITED TO INCLUDE IN TAFS AT THIS
TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN AFTERNOON
CONVECTION AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
853 PM EDT SAT AUG 10 2013
.SYNOPSIS...
ISSUED AT 434 PM EDT SAT AUG 10 2013
A FEW SHOWERS EAST OF I-69 ASSOCIATED WITH A COLD FRONT WILL
CONTINUE TO PUSH EAST OF THE AREA THIS EVENING. SKIES ARE EXPECTED
TO CLEAR OUT OVERNIGHT WITH DRY CONDITIONS CONTINUING THROUGH
SUNDAY. THE NEXT CHANCE SHOWERS AND THUNDERSTORMS WILL ARRIVE IN
THE EARLY HOURS OF MONDAY MORNING AS A LOW PRESSURE SYSTEM MOVES
THROUGH THE REGION.
&&
.UPDATE...
ISSUED AT 827 PM EDT SAT AUG 10 2013
DEPARTING SHEARED VORTICITY MAXIMUM ACROSS THE NORTHERN GREAT LAKES
AND DIURNAL WANING OF SURFACE BASED INSTABILITY WILL RESULT IN
CONTINUED DOWNWARD TREND OF ISOLATED SHOWERS ACROSS THE EXTREME
SOUTHEAST EARLY THIS EVENING. WATER VAPOR IMAGERY EARLY THIS
EVENING AND 22Z RAP INITIALIZATION DOES SEEM TO SUGGEST PRESENCE OF
WEAK UPSTREAM SHORT WAVE ACROSS NORTHWEST ILLINOIS. APPROACH OF
THIS WEAK WAVE LATE THIS EVENING AND CONTINUED WEAK SFC
CONVERGENCE WITH LINGERING INVERTED TROUGH TYPE FEATURE COULD
ALLOW FOR AN ISOLATED SHOWER TO DEVELOP ACROSS EASTERN PORTIONS OF
THE AREA. HOWEVER...HAVE LARGELY MAINTAINED PREVIOUS FORECAST
TRENDS TO MOSTLY CLEAR/PARTLY CLOUDY CONDITIONS WITH CLOUDS
PERSISTING OVER THE NEXT FEW HOURS...ESPECIALLY IN VICINITY OF
AFOREMENTIONED SFC CONVERGENCE ZONE FROM ROUGHLY ANGOLA TO SOUTH
OF FORT WAYNE. WILL ALSO NEED TO MONITOR TRENDS THROUGH REMAINDER
OF EVENING FOR SOME PATCHY FOG POTENTIAL...PARTICULARLY ACROSS
SOUTHEAST PORTIONS OF THE AREA WHERE LOW LEVEL MOISTURE WILL
LIKELY LINGER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 447 PM EDT SAT AUG 10 2013
WK LL CVRG BNDRY IN ASSOCN/W SHEARING DISTURBANCE ALOFT AND IN
CONJUNCTION W/SUFFICIENT SFC BASED DESTABILIZATION ENOUGH TO SPARK A
NARROW BKN BAND OF SHRA ALG A HUNTING TO DEFIANCE LINE THIS AFTN.
ACTIVITY LIKELY NR PEAK AND XPC A GENERAL DOWNTREND THROUGH 23Z.
OTRWS SFC RIDGING TO EXPAND EWD ACRS THE GREAT LAKES IN BEHIND
SECONDARY WK CDFNT PASSING THROUGH THE LAKES TONIGHT YIELDING A
PLEASANTLY COOL AND DRY SUNDAY.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 447 PM EDT SAT AUG 10 2013
A WEAK UPPER LEVEL TROF AND ACCOMPANYING COLD FRONT WILL MOVE SOUTH
ACROSS THE WESTERN GREAT LAKES REGION LATE SUNDAY NIGHT...AND TOWARD
THE OHIO RIVER MONDAY NIGHT. HAVE EXPANDED SHOWER/STORM CHANCES LATE
SUNDAY NIGHT OVER NORTHERN AREAS AS A SURGE OF LOW LEVEL THETA E
REACHES FAR SOUTHERN LOWER MICHIGAN INTO NRN INDIANA. PREFER THE
ECMWF HANDLING THIS SYSTEM...WITH CONVECTIVE DEVELOPMENT IN THE AREA
OF THIS LOW LEVEL THETA E CONVERGENCE OVER LOWER MICHIGAN...AND THEN
MONDAY NIGHT WITH REDEVELOPMENT ALONG THE THE FRONT OVER NRN INDIANA
INTO NW OHIO. HAVE RAISED SHOWER/STORM CHANCES ACCORDINGLY LATE
SUNDAY NIGHT. HAVE ALSO WENT WITH A LITTLE SLOWER FRONTAL PASSAGE
MONDAY NIGHT...WITH SOME LINGERING SHOWERS POSSIBLE OVER SOUTHEAST
AREAS LATE MONDAY NIGHT. NOT OPTIMAL SEVERE STORM PARAMETERS WITH
RELATIVELY LOW CAPES AND LOW LEVEL WINDS MORE UNIDIRECTIONAL.
HOWEVER...THE RIGHT ENTRANCE REGION OF A DEPARTING 80 JET MAX MAY BE
SUFFICIENT TO PRODUCE SOME STRONG STORMS. OTHERWISE...KEPT THE
FORECAST DRY FROM TUESDAY THROUGH THE END OF THE FORECAST PERIOD
SATURDAY. HAVE BLENDED THE GFS AND ECMWF RUNS OVER THIS PERIOD...
WITH THE THERMAL TROF REMAINING OVER THE AREA LONGER THAN EARLIER
MODEL RUNS INDICATED. AS A RESULT...HAVE TRENDED MOST HIGH AND LOW
TEMPS DOWN STARTING WEDNESDAY NIGHT. THIS PATTERN IS MORE LIKE
SEPTEMBER THAN AUGUST...WITH HIGHS IN THE MID TO UPPER 70S AND LOWS
MAINLY IN THE 50S. THE GFS MEAN ENSEMBLE MOS APPEARS ON TRACK...SO
HAVE ATTEMPTED TO FOLLOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 827 PM EDT SAT AUG 10 2013
LOSS OF PEAK INSTABILITY SHOULD LIMIT ANY ADDITIONAL SHOWER
POTENTIAL FOR KFWA THIS EVENING...ALTHOUGH LINGERING LOW LEVEL
CONVERGENT AXIS IN VICINITY OF THE TERMINAL LIKELY TO KEEP SCT-BKN
VFR LOW CLOUDS IN PLACE OVER NEXT FEW HOURS. GRADIENT TO REMAIN
WEAK THROUGH THIS PERIOD WITH ONLY SLIGHT EASTWARD DISPLACEMENT TO
INVERTED SFC TROUGH TYPE FEATURE INTO NORTHWEST OHIO ON SUNDAY.
THUS...WILL KEEP TAFS DRY WITH EXPECTATION ANY ISOLD SHOWER
ACTIVITY WILL REMAIN EAST OF KFWA SUNDAY. WINDS TO REMAIN LIGHT
THROUGH THE PERIOD FAVORING NORTHWEST ON SUNDAY GIVEN SLOW
EASTWARD MIGRATION OF SFC TROUGH. WITH LIGHT WINDS AND CLEARING
SKIES THIS EVENING...MAY NEED TO EVENTUALLY ADDRESS A GREATER FOG
POTENTIAL FOR EARLY SUNDAY MORNING IN FUTURE
AMENDMENTS/ISSUANCES...PARTICULARLY AT KFWA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...KG
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
450 PM EDT FRI AUG 9 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT FRI AUG 9 2013
SCATTERED SHOWERS WILL LINGER OVER SOUTHERN COUNTIES TONIGHT AS A
REMNANT BOUNDARY DRIFTS SLOWLY SOUTH OF THE OHIO RIVER. A SECONDARY
COLD FRONT WILL MOVE ACROSS THE REGION SATURDAY...WITH HIGH PRESSURE
AND DRIER AIR BUILDING INTO CENTRAL INDIANA FOR SATURDAY NIGHT AND
SUNDAY. A STRONGER COLD FRONT WILL BRING THE NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS MONDAY AND TUESDAY. COOLER AIR WILL EXPAND INTO
THE OHIO VALLEY IN THE WAKE OF THIS FRONT FOR MUCH OF THE REST OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
MUCH OF THE THICKER CLOUD COVER HAS SCATTERED OUT INTO A CU FIELD
THIS AFTERNOON...AS THE OLD FRONTAL BOUNDARY NOW APPEARS TO HAVE
SHIFTED SOUTH CLOSER TO THE OHIO RIVER. WITH THE INCREASING
SUNSHINE...TEMPS HAD WARMED INTO LOWER 80S OVER MUCH OF THE REGION
AS OF 19Z.
DRIER AIRMASS SLOWLY ADVECTING SOUTH INTO THE FORECAST AREA...WITH
DEWPOINTS NOW INTO THE LOWER AND MIDDLE 60S NORTH OF I-70. WHILE
DEEPER MOISTURE IS STEADILY BEING SHOVED SOUTH...REMNANT DISTURBANCE
ALOFT OVER SOUTHEAST MISSOURI WILL NEED TO BE MONITORED AS IT TRACKS
INTO THE OHIO VALLEY TONIGHT. STEERING FLOW ALOFT GENERALLY
E/NE...WHICH SHOULD BRING CONVECTION ASSOCIATED WITH THE DISTURBANCE
INTO SOUTHWEST INDIANA BY 22Z. UNLIKE THE MCV FROM LAST NIGHT...THIS
FEATURE IS WEAKER AND IS TRACKING FURTHER TO THE SOUTH.
ADDITIONALLY...INSTABILITY GRADIENT JUST GRAZES SOUTHERN FORECAST
AREA WITH ONLY SUBTLE DESTABILIZATION EXPECTED BETWEEN NOW AND
SUNSET. ONCE AGAIN...CURRENT HRRR GUIDANCE SEEMS TO HAVE CAPTURED
CONVECTION WELL AND HAVE UTILIZED IT FOR THE NEXT SEVERAL HOURS.
WILL CARRY LOW CHANCE POPS MAINLY ALONG AND SOUTH OF A SULLIVAN-
BLOOMINGTON-GREENSBURG LINE THIS EVENING...GRADUALLY ENDING FROM
WEST TO EAST OVERNIGHT. COULD SEE A FEW RUMBLES OF THUNDER OVER
EXTREME SOUTHERN COUNTIES INTO THE EVENING AS WELL.
PRESENCE OF THE DRIER AIRMASS TO THE NORTH AND LESS FAVORABLE
ATMOSPHERIC CONDITIONS SHOULD KEEP ANY APPRECIABLE RAINFALL FROM
PROGRESSING MUCH FURTHER NORTH THAN THE LINE OUTLINED. MUCH OF THE
FORECAST AREA ON THE OTHER HAND WILL BE ENCOMPASSED BY THE BROAD
MID/HIGH LEVEL CLOUD SHIELD ASSOCIATED WITH THE DISTURBANCE...LIKELY
CREATING A PERIOD WITH INCREASED CLOUD COVERAGE THROUGH THE EVENING.
AS HIGHER CLOUDS DIMINISH OVERNIGHT...MODEL SOUNDINGS SUGGEST A
FAVORABLE SETUP FOR REDEVELOPMENT OF STRATUS AND POSSIBLY SOME
PATCHY FOG.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE CONSIDERING LOW LEVEL
THERMALS AS MOST AREAS SHOULD FALL INTO THE MID 60S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES IN THE SOUTH SATURDAY
AND ACROSS THE ENTIRE AREA ON MONDAY.
OLD BOUNDARY SHOULD STILL BE SOMEWHERE NEAR OR JUST SOUTH OF THE
OHIO RIVER SATURDAY MORNING WITH LINGERING LOW LEVEL MOISTURE
EXTENDING NORTH INTO THE FORECAST AREA. SECONDARY FRONT DROPPING
SOUTH FROM THE GREAT LAKES LIKELY TO BE LOCATED SOMEWHERE ACROSS THE
NORTHERN PART OF THE FORECAST AREA AT 12Z. THIS FRONT WILL STEADILY
PUSH SOUTH ACROSS THE FORECAST AREA THROUGH THE DAY...EVENTUALLY
DROPPING SOUTH OF THE OHIO RIVER SATURDAY NIGHT. VERY LITTLE FORCING
ALOFT ACCOMPANYING THE BOUNDARY...BUT PRESENCE OF THE LINGERING LOW
LEVEL MOISTURE OVER SOUTHERN COUNTIES COMBINED WITH WEAK INSTABILITY
MAY BE ENOUGH TO GENERATE ISOLATED CONVECTION DURING THE AFTERNOON
AND EARLY EVENING. WILL CARRY LOW CHANCE POPS SOUTH OF A TERRE
HAUTE-RUSHVILLE LINE.
DEEPER MOISTURE PLUME WILL FINALLY DEPART TO THE SOUTH OVERNIGHT
SATURDAY AS WEAK HIGH PRESSURE BUILDS INTO THE REGION. THE HIGH WILL
REMAIN CENTERED ACROSS CENTRAL INDIANA ON SUNDAY...SQUEEZED BETWEEN
AN UPPER LEVEL DISTURBANCE TRACKING INTO THE WESTERN GREAT LAKES
AND THE BACK EDGE OF THE DEEPER MOISTURE PLUME WHICH IS LIKELY TO
NOT PROGRESS MUCH FURTHER SOUTH THAN THE TENNESSEE AND LOWER OHIO
VALLEYS. WEAK INSTABILITY SHOULD LEND TOWARDS SOME CU DEVELOPMENT IN
THE AFTERNOON BUT LACK OF ANY APPRECIABLE FORCING ALOFT SHOULD KEEP
DRY CONDITIONS IN PLACE ON SUNDAY. THE HIGH WILL SHIFT EAST SUNDAY
NIGHT WITH LOW LEVEL FLOW VEERING BACK AROUND TO A W/SW DIRECTION
MONDAY. THIS WILL ALLOW THE DEEPER MOISTURE PLUME TO ADVECT BACK
NORTH INTO THE REGION ON MONDAY AND INTERACT WITH A COLD FRONT
MOVING IN FROM THE NORTHWEST. THE COMBINATION OF PRECIP WATER VALUES
BACK UP TO 1.5-2 INCHES AND MODEST INSTABILITY SHOULD LEND TO
SCATTERED CONVECTIVE DEVELOPMENT WITH THE FRONT MONDAY AFTERNOON.
TEMPS...GENERALLY LEANED TOWARDS COOLER MAVMOS THROUGH THE PERIOD AS
THE NAM SEEMS TO BE HANGING LOW LEVEL MOISTURE UP A BIT TOO MUCH.
HIGH TEMPS SHOULD REMAIN LARGELY IN THE 80S OVER THE WEEKEND AS LOW
LEVEL THERMALS NOT NEARLY AS COOL AS WERE PROGGED JUST A FEW DAYS
AGO. EDGE WILL BE TAKEN OFF THE HUMIDITY LEVELS HOWEVER WITH COOLER
NIGHTS. POTENTIAL IS THERE FOR TEMPS TO FALL INTO THE MID AND UPPER
50S IN A NUMBER OF LOCATIONS SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 232 PM EDT FRI AUG 9 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
AN UPPER TROUGH WILL CONTINUE ACROSS THE AREA THROUGH THE LONG TERM.
THIS WILL KEEP TEMPERATURES BELOW AVERAGE THROUGH THE PERIOD.
AS THE COLD FRONT USHERS IN THE COOL CANADIAN AIR MONDAY NIGHT INTO
TUESDAY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE...MAINLY MONDAY
NIGHT. AFTERWARD HIGH PRESSURE WILL BUILD IN AND PROVIDE DRY
CONDITIONS TUESDAY NIGHT THROUGH FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 09/2100Z TAF UPDATE/...
ISSUED AT 448 PM EDT FRI AUG 9 2013
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
ANY LINGERING MVFR CEILINGS SHOULD LIFT TO VFR VERY EARLY IN THE
PERIOD. VFR WILL THEN RULE UNTIL AROUND 06Z WHEN MVFR FOG/CEILINGS
WILL FORM WITH THE POTENTIAL FOR IFR. VFR RETURNS LATE SATURDAY
MORNING.
SATELLITE SHOWS STRATUS CONTINUING TO BREAK UP ALLOWING HEATING TO
LIFT THE CEILINGS. STILL EXPECT SCATTERED TO BROKEN CU THROUGH THE
AFTERNOON. LOOKS LIKE CHANCES FOR CONVECTION WILL HOLD OFF UNTIL
LATE AFTERNOON AND MAINLY FOR KHUF/KBMG. CHANCES ARE TOO LOW TO
MENTION IN TAFS AT THE MOMENT.
LINGERING LOW LEVEL MOISTURE WILL LEAD TO FOG DEVELOPMENT WITH SOME
STRATUS LIKELY TONIGHT. WILL GO MVFR FOR NOW...BUT POTENTIAL FOR IFR
IS THERE. WILL USE BCFG TO HINT AT THAT POSSIBILITY. FOG/STRATUS
WILL BURN OFF SATURDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50/TDUD
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
343 PM EDT FRI AUG 9 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT FRI AUG 9 2013
SCATTERED SHOWERS WILL LINGER OVER SOUTHERN COUNTIES TONIGHT AS A
REMNANT BOUNDARY DRIFTS SLOWLY SOUTH OF THE OHIO RIVER. A SECONDARY
COLD FRONT WILL MOVE ACROSS THE REGION SATURDAY...WITH HIGH PRESSURE
AND DRIER AIR BUILDING INTO CENTRAL INDIANA FOR SATURDAY NIGHT AND
SUNDAY. A STRONGER COLD FRONT WILL BRING THE NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS MONDAY AND TUESDAY. COOLER AIR WILL EXPAND INTO
THE OHIO VALLEY IN THE WAKE OF THIS FRONT FOR MUCH OF THE REST OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
MUCH OF THE THICKER CLOUD COVER HAS SCATTERED OUT INTO A CU FIELD
THIS AFTERNOON...AS THE OLD FRONTAL BOUNDARY NOW APPEARS TO HAVE
SHIFTED SOUTH CLOSER TO THE OHIO RIVER. WITH THE INCREASING
SUNSHINE...TEMPS HAD WARMED INTO LOWER 80S OVER MUCH OF THE REGION
AS OF 19Z.
DRIER AIRMASS SLOWLY ADVECTING SOUTH INTO THE FORECAST AREA...WITH
DEWPOINTS NOW INTO THE LOWER AND MIDDLE 60S NORTH OF I-70. WHILE
DEEPER MOISTURE IS STEADILY BEING SHOVED SOUTH...REMNANT DISTURBANCE
ALOFT OVER SOUTHEAST MISSOURI WILL NEED TO BE MONITORED AS IT TRACKS
INTO THE OHIO VALLEY TONIGHT. STEERING FLOW ALOFT GENERALLY
E/NE...WHICH SHOULD BRING CONVECTION ASSOCIATED WITH THE DISTURBANCE
INTO SOUTHWEST INDIANA BY 22Z. UNLIKE THE MCV FROM LAST NIGHT...THIS
FEATURE IS WEAKER AND IS TRACKING FURTHER TO THE SOUTH.
ADDITIONALLY...INSTABILITY GRADIENT JUST GRAZES SOUTHERN FORECAST
AREA WITH ONLY SUBTLE DESTABILIZATION EXPECTED BETWEEN NOW AND
SUNSET. ONCE AGAIN...CURRENT HRRR GUIDANCE SEEMS TO HAVE CAPTURED
CONVECTION WELL AND HAVE UTILIZED IT FOR THE NEXT SEVERAL HOURS.
WILL CARRY LOW CHANCE POPS MAINLY ALONG AND SOUTH OF A SULLIVAN-
BLOOMINGTON-GREENSBURG LINE THIS EVENING...GRADUALLY ENDING FROM
WEST TO EAST OVERNIGHT. COULD SEE A FEW RUMBLES OF THUNDER OVER
EXTREME SOUTHERN COUNTIES INTO THE EVENING AS WELL.
PRESENCE OF THE DRIER AIRMASS TO THE NORTH AND LESS FAVORABLE
ATMOSPHERIC CONDITIONS SHOULD KEEP ANY APPRECIABLE RAINFALL FROM
PROGRESSING MUCH FURTHER NORTH THAN THE LINE OUTLINED. MUCH OF THE
FORECAST AREA ON THE OTHER HAND WILL BE ENCOMPASSED BY THE BROAD
MID/HIGH LEVEL CLOUD SHIELD ASSOCIATED WITH THE DISTURBANCE...LIKELY
CREATING A PERIOD WITH INCREASED CLOUD COVERAGE THROUGH THE EVENING.
AS HIGHER CLOUDS DIMINISH OVERNIGHT...MODEL SOUNDINGS SUGGEST A
FAVORABLE SETUP FOR REDEVELOPMENT OF STRATUS AND POSSIBLY SOME
PATCHY FOG.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE CONSIDERING LOW LEVEL
THERMALS AS MOST AREAS SHOULD FALL INTO THE MID 60S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES IN THE SOUTH SATURDAY
AND ACROSS THE ENTIRE AREA ON MONDAY.
OLD BOUNDARY SHOULD STILL BE SOMEWHERE NEAR OR JUST SOUTH OF THE
OHIO RIVER SATURDAY MORNING WITH LINGERING LOW LEVEL MOISTURE
EXTENDING NORTH INTO THE FORECAST AREA. SECONDARY FRONT DROPPING
SOUTH FROM THE GREAT LAKES LIKELY TO BE LOCATED SOMEWHERE ACROSS THE
NORTHERN PART OF THE FORECAST AREA AT 12Z. THIS FRONT WILL STEADILY
PUSH SOUTH ACROSS THE FORECAST AREA THROUGH THE DAY...EVENTUALLY
DROPPING SOUTH OF THE OHIO RIVER SATURDAY NIGHT. VERY LITTLE FORCING
ALOFT ACCOMPANYING THE BOUNDARY...BUT PRESENCE OF THE LINGERING LOW
LEVEL MOISTURE OVER SOUTHERN COUNTIES COMBINED WITH WEAK INSTABILITY
MAY BE ENOUGH TO GENERATE ISOLATED CONVECTION DURING THE AFTERNOON
AND EARLY EVENING. WILL CARRY LOW CHANCE POPS SOUTH OF A TERRE
HAUTE-RUSHVILLE LINE.
DEEPER MOISTURE PLUME WILL FINALLY DEPART TO THE SOUTH OVERNIGHT
SATURDAY AS WEAK HIGH PRESSURE BUILDS INTO THE REGION. THE HIGH WILL
REMAIN CENTERED ACROSS CENTRAL INDIANA ON SUNDAY...SQUEEZED BETWEEN
AN UPPER LEVEL DISTURBANCE TRACKING INTO THE WESTERN GREAT LAKES
AND THE BACK EDGE OF THE DEEPER MOISTURE PLUME WHICH IS LIKELY TO
NOT PROGRESS MUCH FURTHER SOUTH THAN THE TENNESSEE AND LOWER OHIO
VALLEYS. WEAK INSTABILITY SHOULD LEND TOWARDS SOME CU DEVELOPMENT IN
THE AFTERNOON BUT LACK OF ANY APPRECIABLE FORCING ALOFT SHOULD KEEP
DRY CONDITIONS IN PLACE ON SUNDAY. THE HIGH WILL SHIFT EAST SUNDAY
NIGHT WITH LOW LEVEL FLOW VEERING BACK AROUND TO A W/SW DIRECTION
MONDAY. THIS WILL ALLOW THE DEEPER MOISTURE PLUME TO ADVECT BACK
NORTH INTO THE REGION ON MONDAY AND INTERACT WITH A COLD FRONT
MOVING IN FROM THE NORTHWEST. THE COMBINATION OF PRECIP WATER VALUES
BACK UP TO 1.5-2 INCHES AND MODEST INSTABILITY SHOULD LEND TO
SCATTERED CONVECTIVE DEVELOPMENT WITH THE FRONT MONDAY AFTERNOON.
TEMPS...GENERALLY LEANED TOWARDS COOLER MAVMOS THROUGH THE PERIOD AS
THE NAM SEEMS TO BE HANGING LOW LEVEL MOISTURE UP A BIT TOO MUCH.
HIGH TEMPS SHOULD REMAIN LARGELY IN THE 80S OVER THE WEEKEND AS LOW
LEVEL THERMALS NOT NEARLY AS COOL AS WERE PROGGED JUST A FEW DAYS
AGO. EDGE WILL BE TAKEN OFF THE HUMIDITY LEVELS HOWEVER WITH COOLER
NIGHTS. POTENTIAL IS THERE FOR TEMPS TO FALL INTO THE MID AND UPPER
50S IN A NUMBER OF LOCATIONS SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 232 PM EDT FRI AUG 9 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
AN UPPER TROUGH WILL CONTINUE ACROSS THE AREA THROUGH THE LONG TERM.
THIS WILL KEEP TEMPERATURES BELOW AVERAGE THROUGH THE PERIOD.
AS THE COLD FRONT USHERS IN THE COOL CANADIAN AIR MONDAY NIGHT INTO
TUESDAY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE...MAINLY MONDAY
NIGHT. AFTERWARD HIGH PRESSURE WILL BUILD IN AND PROVIDE DRY
CONDITIONS TUESDAY NIGHT THROUGH FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 091800Z TAFS/...
ISSUED AT 1259 PM EDT FRI AUG 9 2013
ANY LINGERING MVFR CEILINGS SHOULD LIFT TO VFR VERY EARLY IN THE
PERIOD. VFR WILL THEN RULE UNTIL AROUND 06Z WHEN MVFR FOG/CEILINGS
WILL FORM WITH THE POTENTIAL FOR IFR. VFR RETURNS LATE SATURDAY
MORNING.
SATELLITE SHOWS STRATUS CONTINUING TO BREAK UP ALLOWING HEATING TO
LIFT THE CEILINGS. STILL EXPECT SCATTERED TO BROKEN CU THROUGH THE
AFTERNOON. LOOKS LIKE CHANCES FOR CONVECTION WILL HOLD OFF UNTIL
LATE AFTERNOON AND MAINLY FOR KHUF/KBMG. CHANCES ARE TOO LOW TO
MENTION IN TAFS AT THE MOMENT.
LINGERING LOW LEVEL MOISTURE WILL LEAD TO FOG DEVELOPMENT WITH SOME
STRATUS LIKELY TONIGHT. WILL GO MVFR FOR NOW...BUT POTENTIAL FOR IFR
IS THERE. WILL USE BCFG TO HINT AT THAT POSSIBILITY. FOG/STRATUS
WILL BURN OFF SATURDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50
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
201 AM EDT FRI AUG 9 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 953 PM EDT THU AUG 8 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS LAST FEW HOURS
ACROSS OUR SOUTH AS MCV APPROACHES. RAPID REFRESH FOLLOWS THIS IDEAL
WITH NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR SOUTH THROUGH
ABOUT 06Z AND WITH MUCH LESS ACTIVITY AFTER THAT. ALSO CONCERNED
ABOUT HEAVY RAIN POTENTIAL NEXT SEVERAL HOURS AS PRECIPITABLE WATER
RUNNING ABOUT 2 TO 2.2 INCHES. WILL CONSIDER AREAL FLOOD ADVISORIES
IN SOME AREAS TO COVER THIS.
FARTHER NORTH...CURRENT FORECAST SEEMS TO BE ON TRACK. COLD FRONT WILL
MOVE SLOWLY SOUTH ACROSS OUR AREA OVERNIGHT. NAM SEEMS TO COOL TEMPERATURES
ACROSS OUR NORTHWEST TOO MUCH BY DAYBREAK. MADE A FEW TWEAKS IN
TEMPERATURES FROM PREVIOUS FORECAST. BUT IN MOST AREAS THEY SEEM OK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 200 AM EDT FRI AUG 9 2013
ENSEMBLES INDICATE A RATHER STABLE WEATHER PATTERN DURING THIS
PERIOD. SUBTROPICAL RIDGE REMAINS ALONG THE GULF COAST/SOUTHERN
PLAINS REGION...WHILE UPPER TROUGHING CONTINUES OVER THE NORTHEAST
PARTS OF THE COUNTRY.
ENSEMBLES SUGGEST AN UPPER DISTURBANCE MAY MOVE ACROSS THE AREA
EARLY NEXT WEEK...AROUND MONDAY AND TUESDAY. WILL CONTINUE WITH
CHANCE POPS AT THOSE TIMES. PRECIPITATION THREAT DIMINISHES BY NEXT
WEDNESDAY AND THURSDAY WITH THE ENSEMBLES SHOWING LITTLE TO NO QPF
POTENTIAL BY THEN. WILL GO DRY AFTER TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 09/0600Z TAFS/...
ISSUED AT 1233 AM EDT FRI AUG 9 2013
RAIN SHOWERS REMAIN CONFINED TO KBMG AND KHUF...SO WILL ONLY CARRY
MENTION OF VCSH AT THOSE TAF SITES THROUGH FRI 08Z. MVFR CONDITIONS
WILL BE LIKELY AT ALL TAF SITES THOUGH EARLY THIS MORNING DUE TO LOW
CEILINGS AND FOG FORMATION WITH MOIST AIRMASS IN PLACE.
HOWEVER...THE FRONTAL BOUNDARY THAT IS GENERATING THE CURRENT WEAK
CONVECTION OVER SOUTHERN TAF SITES WILL SHIFT FURTHER SOUTH LATER
TODAY...ALLOWING DRIER AIR TO FILTER INTO TAF SITES AND A RETURN TO
VFR CONDITIONS BY THIS AFTERNOON. WINDS WILL BE NORTHERLY AT 2 TO 8
KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...TDUD
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
1233 AM EDT FRI AUG 9 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 953 PM EDT THU AUG 8 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS LAST FEW HOURS
ACROSS OUR SOUTH AS MCV APPROACHES. RAPID REFRESH FOLLOWS THIS IDEAL
WITH NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR SOUTH THROUGH
ABOUT 06Z AND WITH MUCH LESS ACTIVITY AFTER THAT. ALSO CONCERNED
ABOUT HEAVY RAIN POTENTIAL NEXT SEVERAL HOURS AS PRECIPITABLE WATER
RUNNING ABOUT 2 TO 2.2 INCHES. WILL CONSIDER AREAL FLOOD ADVISORIES
IN SOME AREAS TO COVER THIS.
FARTHER NORTH...CURRENT FORECAST SEEMS TO BE ON TRACK. COLD FRONT WILL
MOVE SLOWLY SOUTH ACROSS OUR AREA OVERNIGHT. NAM SEEMS TO COOL TEMPERATURES
ACROSS OUR NORTHWEST TOO MUCH BY DAYBREAK. MADE A FEW TWEAKS IN
TEMPERATURES FROM PREVIOUS FORECAST. BUT IN MOST AREAS THEY SEEM OK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 09/0600Z TAFS/...
ISSUED AT 1233 AM EDT FRI AUG 9 2013
RAIN SHOWERS REMAIN CONFINED TO KBMG AND KHUF...SO WILL ONLY CARRY
MENTION OF VCSH AT THOSE TAF SITES THROUGH FRI 08Z. MVFR CONDITIONS
WILL BE LIKELY AT ALL TAF SITES THOUGH EARLY THIS MORNING DUE TO LOW
CEILINGS AND FOG FORMATION WITH MOIST AIRMASS IN PLACE.
HOWEVER...THE FRONTAL BOUNDARY THAT IS GENERATING THE CURRENT WEAK
CONVECTION OVER SOUTHERN TAF SITES WILL SHIFT FURTHER SOUTH LATER
TODAY...ALLOWING DRIER AIR TO FILTER INTO TAF SITES AND A RETURN TO
VFR CONDITIONS BY THIS AFTERNOON. WINDS WILL BE NORTHERLY AT 2 TO 8
KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....50
AVIATION...TDUD
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
1254 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1247 PM CDT FRI AUG 9 2013
WEAK COLD FRONT CONTINUES TO MAKE STEADY PROGRESS INTO THE DVN CWA
AND EXTENDED FROM NEAR FREEPORT TO JUST SOUTH OF IOWA CITY. THERE
IS A NARROW BAND OF LOWER CLOUDS BEHIND THE FRONT OTHERWISE MID
AND HIGH LEVEL CLOUDS WERE OVER THE CWA. HIGH TEMPERATURES STILL
LOOK ON TARGET TO BE IN THE UPPER 70S TO LOWER 80S AT MOST LOCATIONS.
NO SHOWERS HAVE POPPED UP AS OF YET BUT THE RAPID REFRESH STILL
SUGGESTS ISOLATED SHOWERS OR SPRINKLES THIS AFTERNOON NEAR THE FRONT.
UPDATE ISSUED AT 1055 AM CDT FRI AUG 9 2013
WEAK COLD FRONT WAS NEARING OUR FAR NW CWA BUT THE MAIN DYNAMICS
ASSOCIATED WITH AN UPPER LEVEL TROUGH WAS WELL TO OUR NORTH. WILL
CONTINUE WITH THE RAPID REFRESH MESO MODEL OF ONLY ISOLATED
SHOWERS OR SPRINKLES ACCOMPANYING THE FRONT AS IT TRACKS SOUTHEAST
ACROSS THE CWA THROUGH THE AFTERNOON. MAINLY MID/HIGH LEVEL CLOUDS
WILL BE OVER THE CWA. CURRENT TEMPERATURES RUNNING SLIGHTLY HIGHER
THAN FORECAST AT SOME LOCATIONS BUT ALL IN ALL THE GOING FORECAST
HIGHS LOOK REASONABLE...MAINLY IN THE UPPER 70S TO LOWER 80S.
FANTASTIC WEATHER EXPECTED TONIGHT AND SATURDAY AS HIGH PRESSURE
BUILDS INTO THE REGION. TEMPERATURES AND HUMIDITY LEVELS WILL BE
VERY COMFORTABLE FOR MID AUGUST.
MEANWHILE...A BAND OF RAIN AND A FEW THUNDERSTORMS WAS LOCATED
ACROSS EASTERN KS INTO CENTRAL MO WHICH WAS OCCURRING ALONG AN 850
MB FRONTAL BOUNDARY. HOWEVER...THAT WILL REMAIN WELL TO THE SOUTH
OF THE DVN CWA.
UPDATE ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS DEVELOPED ALONG/EAST OF THE
MISSISSIPPI IN WEST CENTRAL ILLINOIS. THE FEW OBS REPORTING THIS
FOG DO SHOW IT IS LOCALLY DENSE AT TIMES. WITH THE SUN ALREADY
UP...CONDITIONS SHOULD BEGIN TO IMPROVE OVER THE NEXT 90 MINUTES
SO NO HEADLINE IS BEING CONSIDERED.
THE SPRINKLES AND ISOLATED SHOWERS OVER CENTRAL/SOUTHERN IOWA HAVE
DISSIPATED AS THE FORCING WEAKENED. ALONG THE MN/IA BORDER THIS
CONVECTION IS ALSO WEAKENING AS LIFT AND CONVERGENCE WEAKENS. THE
FRONTAL PASSAGE ACROSS THE AREA IS EXPECTED TO BE MAINLY DRY DUE
TO WEAK FORCING AND NOT MUCH IN THE WAY OF MOISTURE.
HOWEVER...ISOLATED WEAK DIURNAL SPRINKLES/SHOWERS CANNOT BE
ENTIRELY RULED OUT DUE TO THE TIMING OF THE FRONTAL PASSAGE. IF
DIURNAL CONVECTION DEVELOPS IT WILL DISSIPATE SHORTLY AFTER SUNSET.
&&
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1247 PM CDT FRI AUG 9 2013
MAINLY VFR CONDS THIS AFTERNOON. THERE IS A NARROW BAND OF OCNL
MVFR CIGS BEHIND A WEAK COLD FRONT DROPPING SOUTHWARD ACROSS
EASTERN IA. THE FRONT WILL MOVE ACROSS THE TAF SITES THIS AFTERNOON
WITH ONLY ISOLATED SHOWERS OR SPRINKLES ACCOMPANYING THE FRONT.
VFR CONDS WITH SKC TONIGHT AND SATURDAY AS HIGH PRESSURE BUILDS
INTO THE REGION. VARIABLE WINDS BECOMING NORTHWEST BEHIND THE
FRONT. NORTH WINDS TONIGHT AND SATURDAY. WIND SPEEDS WILL BE LESS
THAN 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1234 PM CDT FRI AUG 9 2013
.SHORT TERM.../TODAY /...
ISSUED AT 313 AM CDT FRI AUG 9 2013
WEAK COLD FRONTAL BOUNDARY EXTENDING FROM FROM MN INTO NWRN IA INTO
KS WILL MOVE SOUTHEAST AND EXIT THE CWA BY AROUND MID DAY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING ALONG THE FRONT WILL
CONTINUE TO MOVE ESEWD WITH THE FRONT HRRR HAS A PRETTY DECENT
HANDLE ON THE PRECIP AND SUGGESTS THE PRECIP WILL BE OUT OF THE CWA
BY AROUND 18Z. HIGH PRESSURE WILL BEGIN BUILDING INTO THE STATE
THIS AFTERNOON FROM THE NORTHWEST.
.LONG TERM.../TONIGHT THROUGH THURSDAY/...
ISSUED AT 313 AM CDT FRI AUG 9 2013
SIMILAR CHALLENGES COMING UP COMPARED TO PAST FEW DAYS. APPROACHING
SHORT WAVES AND SYNOPTIC FEATURES REMAIN RATHER WEAK GIVEN TIME OF
YEAR AND QUESTIONS REVOLVING AROUND COVERAGE AND CHANCES FOR RAIN IN
THE FORECAST. FOR NOW...WEAK BOUNDARY WILL BE SOUTH OF THE REGION BY
THIS EVENING AND DRY WEATHER EXPECTED THROUGH LATE SATURDAY NIGHT.
FINALLY ON SUNDAY ANOTHER NORTHERN STREAM WAVE WILL ATTEMPT TO CROSS
THE AREA WITH SOME MOISTURE ASSOCIATED WITH IT. THIS WILL ONCE AGAIN
BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA SUNDAY INTO
MONDAY AFTERNOON. FOLLOWING THAT HIGH PRESSURE WILL DROP SOUTH OUT
OF CANADA AND KEEP TEMPERATURES COMFORTABLE IN THE UPPER 70S TO
LOWER 80S WITH SLIGHTLY COOLER READINGS OVER THE NORTH. OVERALL
QUITE PLEASANT FOR AUGUST...THOUGH A BIT BELOW NORMAL. MOST OF THE
MED RANGE MODELS SUGGEST THAT THE HIGH OVER THE GREAT LAKES WILL
REMAIN ANCHORED THERE UNTIL MID TO LATE NEXT WEEK. FOR THE MOST PART
OUR WEATHER WILL REMAIN RATHER UNEVENTFUL WITH DRIER AND COOLER THAN
NORMAL CONDITIONS.
&&
.AVIATION...09/18Z
ISSUED AT 1231 PM CDT FRI AUG 9 2013
SURFACE FRONT CURRENTLY PASSING THROUGH SOUTHERN IOWA WILL EXIT
THE STATE BY LATE AFTERNOON. ISOLATED STORMS ARE EXPECTED ALONG
THIS BOUNDARY AS IT MOVES SOUTHEAST WITH WINDS GENERALLY NORTH TO
NORTHEAST BEHIND THE BOUNDARY. WIDESPREAD VFR CONDITIONS ARE
EXPECTED OVERNIGHT INTO SATURDAY MORNING WITH UNRESTRICTED VSBYS
AND ANY CEILINGS REMAINING AT OR ABOVE TWELVE THOUSAND FEET.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MS AUG 13
LONG TERM...REV
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1102 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1055 AM CDT FRI AUG 9 2013
WEAK COLD FRONT WAS NEARING OUR FAR NW CWA BUT THE MAIN DYNAMICS
ASSOCIATED WITH AN UPPER LEVEL TROUGH WAS WELL TO OUR NORTH. WILL
CONTINUE WITH THE RAPID REFRESH MESO MODEL OF ONLY ISOLATED
SHOWERS OR SPRINKLES ACCOMPANYING THE FRONT AS IT TRACKS SOUTHEAST
ACROSS THE CWA THROUGH THE AFTERNOON. MAINLY MID/HIGH LEVEL CLOUDS
WILL BE OVER THE CWA. CURRENT TEMPERATURES RUNNING SLIGHTLY HIGHER
THAN FORECAST AT SOME LOCATIONS BUT ALL IN ALL THE GOING FORECAST
HIGHS LOOK REASONABLE...MAINLY IN THE UPPER 70S TO LOWER 80S.
FANTASTIC WEATHER EXPECTED TONIGHT AND SATURDAY AS HIGH PRESSURE
BUILDS INTO THE REGION. TEMPERATURES AND HUMIDITY LEVELS WILL BE
VERY COMFORTABLE FOR MID AUGUST.
MEANWHILE...A BAND OF RAIN AND A FEW THUNDERSTORMS WAS LOCATED
ACROSS EASTERN KS INTO CENTRAL MO WHICH WAS OCCURRING ALONG AN 850
MB FRONTAL BOUNDARY. HOWEVER...THAT WILL REMAIN WELL TO THE SOUTH
OF THE DVN CWA.
UPDATE ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS DEVELOPED ALONG/EAST OF THE
MISSISSIPPI IN WEST CENTRAL ILLINOIS. THE FEW OBS REPORTING THIS
FOG DO SHOW IT IS LOCALLY DENSE AT TIMES. WITH THE SUN ALREADY
UP...CONDITIONS SHOULD BEGIN TO IMPROVE OVER THE NEXT 90 MINUTES
SO NO HEADLINE IS BEING CONSIDERED.
THE SPRINKLES AND ISOLATED SHOWERS OVER CENTRAL/SOUTHERN IOWA HAVE
DISSIPATED AS THE FORCING WEAKENED. ALONG THE MN/IA BORDER THIS
CONVECTION IS ALSO WEAKENING AS LIFT AND CONVERGENCE WEAKENS. THE
FRONTAL PASSAGE ACROSS THE AREA IS EXPECTED TO BE MAINLY DRY DUE
TO WEAK FORCING AND NOT MUCH IN THE WAY OF MOISTURE.
HOWEVER...ISOLATED WEAK DIURNAL SPRINKLES/SHOWERS CANNOT BE
ENTIRELY RULED OUT DUE TO THE TIMING OF THE FRONTAL PASSAGE. IF
DIURNAL CONVECTION DEVELOPS IT WILL DISSIPATE SHORTLY AFTER SUNSET.
&&
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 1055 AM CDT FRI AUG 9 2013
VFR CONDS THROUGH TONIGHT. A WEAK COLD FRONT WILL MOVE ACROSS THE
TAF SITES THIS AFTERNOON WITH ONLY ISOLATED SHOWERS OR SPRINKLES
ACCOMPANYING THE FRONT. VARIABLE WINDS BECOMING NORTHWEST BEHIND
THE FRONT. NORTH WINDS TONIGHT AS HIGH PRESSURE BEGINS BUILDING
INTO THE REGION. WIND SPEEDS WILL BE LESS THAN 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
657 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS DEVELOPED ALONG/EAST OF THE
MISSISSIPPI IN WEST CENTRAL ILLINOIS. THE FEW OBS REPORTING THIS
FOG DO SHOW IT IS LOCALLY DENSE AT TIMES. WITH THE SUN ALREADY
UP...CONDITIONS SHOULD BEGIN TO IMPROVE OVER THE NEXT 90 MINUTES
SO NO HEADLINE IS BEING CONSIDERED.
THE SPRINKLES AND ISOLATED SHOWERS OVER CENTRAL/SOUTHERN IOWA HAVE
DISSIPATED AS THE FORCING WEAKENED. ALONG THE MN/IA BORDER THIS
CONVECTION IS ALSO WEAKENING AS LIFT AND CONVERGENCE WEAKENS. THE
FRONTAL PASSAGE ACROSS THE AREA IS EXPECTED TO BE MAINLY DRY DUE
TO WEAK FORCING AND NOT MUCH IN THE WAY OF MOISTURE.
HOWEVER...ISOLATED WEAK DIURNAL SPRINKLES/SHOWERS CANNOT BE
ENTIRELY RULED OUT DUE TO THE TIMING OF THE FRONTAL PASSAGE. IF
DIURNAL CONVECTION DEVELOPS IT WILL DISSIPATE SHORTLY AFTER SUNSET.
&&
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS CREATED VLIFR CONDITIONS AT KBRL.
THESE CONDITIONS WILL IMPROVE TO VFR THROUGH 14Z/09. OTHERWISE
EXPECT VFR CONDITIONS THROUGH 12Z/10 AS A WEAK FRONT MOVES THROUGH
THE AREA. ISOLATED SPRINKLES MAY BE POSSIBLE THROUGH 21Z/09 BUT
THE PROBABILITY OF A SHRA AFFECTING A TAF SITE IS AT BEST 5
PERCENT. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS DES MOINES IA
641 AM CDT FRI AUG 9 2013
.SHORT TERM.../TODAY /...
ISSUED AT 313 AM CDT FRI AUG 9 2013
WEAK COLD FRONTAL BOUNDARY EXTENDING FROM FROM MN INTO NWRN IA INTO
KS WILL MOVE SOUTHEAST AND EXIT THE CWA BY AROUND MID DAY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING ALONG THE FRONT WILL
CONTINUE TO MOVE ESEWD WITH THE FRONT HRRR HAS A PRETTY DECENT
HANDLE ON THE PRECIP AND SUGGESTS THE PRECIP WILL BE OUT OF THE CWA
BY AROUND 18Z. HIGH PRESSURE WILL BEGIN BUILDING INTO THE STATE
THIS AFTERNOON FROM THE NORTHWEST.
.LONG TERM.../TONIGHT THROUGH THURSDAY/...
ISSUED AT 313 AM CDT FRI AUG 9 2013
SIMILAR CHALLENGES COMING UP COMPARED TO PAST FEW DAYS. APPROACHING
SHORT WAVES AND SYNOPTIC FEATURES REMAIN RATHER WEAK GIVEN TIME OF
YEAR AND QUESTIONS REVOLVING AROUND COVERAGE AND CHANCES FOR RAIN IN
THE FORECAST. FOR NOW...WEAK BOUNDARY WILL BE SOUTH OF THE REGION BY
THIS EVENING AND DRY WEATHER EXPECTED THROUGH LATE SATURDAY NIGHT.
FINALLY ON SUNDAY ANOTHER NORTHERN STREAM WAVE WILL ATTEMPT TO CROSS
THE AREA WITH SOME MOISTURE ASSOCIATED WITH IT. THIS WILL ONCE AGAIN
BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA SUNDAY INTO
MONDAY AFTERNOON. FOLLOWING THAT HIGH PRESSURE WILL DROP SOUTH OUT
OF CANADA AND KEEP TEMPERATURES COMFORTABLE IN THE UPPER 70S TO
LOWER 80S WITH SLIGHTLY COOLER READINGS OVER THE NORTH. OVERALL
QUITE PLEASANT FOR AUGUST...THOUGH A BIT BELOW NORMAL. MOST OF THE
MED RANGE MODELS SUGGEST THAT THE HIGH OVER THE GREAT LAKES WILL
REMAIN ANCHORED THERE UNTIL MID TO LATE NEXT WEEK. FOR THE MOST PART
OUR WEATHER WILL REMAIN RATHER UNEVENTFUL WITH DRIER AND COOLER THAN
NORMAL CONDITIONS.
&&
.AVIATION...09/12Z
ISSUED AT 637 AM CDT FRI AUG 9 2013
WEAK COLD FRONT NERN IA INTO SOUTH CENTRAL IOWA WILL PASS
SOUTHEAST OF THE STATE THIS MORNING. ISOLATED SHOWERS OVER THE
NE RN PART OF THE STATE WILL END THIS MORNING. MID LEVEL CLOUDINESS
WILL CLEAR OUT OF THE STATE BY MID MORNING...WITH ONLY HIGH CLOUDS
REMAINING OVER THE SERN HALF. FLOW BECOMING NW-NLY STATEWIDE TODAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MS AUG 13
LONG TERM...REV
AVIATION...MS AUG 13
AREA FORECAST DISCUSSION
NWS DES MOINES IA
325 AM CDT FRI AUG 9 2013
.SHORT TERM.../TODAY /...
ISSUED AT 313 AM CDT FRI AUG 9 2013
WEAK COLD FRONTAL BOUNDARY EXTENDING FROM FROM MN INTO NWRN IA INTO
KS WILL MOVE SOUTHEAST AND EXIT THE CWA BY AROUND MID DAY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING ALONG THE FRONT WILL
CONTINUE TO MOVE ESEWD WITH THE FRONT HRRR HAS A PRETTY DECENT
HANDLE ON THE PRECIP AND SUGGESTS THE PRECIP WILL BE OUT OF THE CWA
BY AROUND 18Z. HIGH PRESSURE WILL BEGIN BUILDING INTO THE STATE
THIS AFTERNOON FROM THE NORTHWEST.
.LONG TERM.../TONIGHT THROUGH THURSDAY/...
ISSUED AT 313 AM CDT FRI AUG 9 2013
SIMILAR CHALLENGES COMING UP COMPARED TO PAST FEW DAYS. APPROACHING
SHORT WAVES AND SYNOPTIC FEATURES REMAIN RATHER WEAK GIVEN TIME OF
YEAR AND QUESTIONS REVOLVING AROUND COVERAGE AND CHANCES FOR RAIN IN
THE FORECAST. FOR NOW...WEAK BOUNDARY WILL BE SOUTH OF THE REGION BY
THIS EVENING AND DRY WEATHER EXPECTED THROUGH LATE SATURDAY NIGHT.
FINALLY ON SUNDAY ANOTHER NORTHERN STREAM WAVE WILL ATTEMPT TO CROSS
THE AREA WITH SOME MOISTURE ASSOCIATED WITH IT. THIS WILL ONCE AGAIN
BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA SUNDAY INTO
MONDAY AFTERNOON. FOLLOWING THAT HIGH PRESSURE WILL DROP SOUTH OUT
OF CANADA AND KEEP TEMPERATURES COMFORTABLE IN THE UPPER 70S TO
LOWER 80S WITH SLIGHTLY COOLER READINGS OVER THE NORTH. OVERALL
QUITE PLEASANT FOR AUGUST...THOUGH A BIT BELOW NORMAL. MOST OF THE
MED RANGE MODELS SUGGEST THAT THE HIGH OVER THE GREAT LAKES WILL
REMAIN ANCHORED THERE UNTIL MID TO LATE NEXT WEEK. FOR THE MOST PART
OUR WEATHER WILL REMAIN RATHER UNEVENTFUL WITH DRIER AND COOLER THAN
NORMAL CONDITIONS.
&&
.AVIATION...09/06Z
ISSUED AT 1149 PM CDT THU AUG 8 2013
VFR CONDITIONS WILL PREVAIL THROUGHOUT THE ENTIRE FORECAST AREA AS
HIGH PRESSURE DOMINATES THE PATTERN.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MS
LONG TERM...REV
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 AM CDT FRI AUG 9 2013
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1146 PM CDT THU AUG 8 2013
WEAK HIGH PRESSURE WILL KEEP VFR CONDITIONS FOR AT LEAST THE NEXT
24 HOURS. PASSING UPPER DISTURBANCES OVERNIGHT INTO MID MORNING WILL
PRODUCE BKN-OVC CLOUDS WITH BASES AOA 9K AGL. ISOLATED SPRINKLES
MAY OCCUR WITH NO RESTRICTION TO VISIBILITIES UNTIL 09/16Z. SKIES
WILL THEN BECOME MOSTLY CLEAR BY MID DAY. LIGHT WINDS TENDING TO
BE FROM THE NORTHEAST TONIGHT WILL SHIFT TO THE NORTHWEST AT 5 TO
10 MPH BY MID DAY FRIDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...NICHOLS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
531 PM MDT SAT AUG 10 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 217 PM MDT SAT AUG 10 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
CLEAR TO PARTLY CLOUDY. TEMPERATURES HAVE WARMED INTO MID 70S TO MID
80S. WINDS WERE GENERALLY FROM THE SOUTH AT 10 TO 20 MPH WITH GUSTS
25 TO 30 MPH. THE STRONGER WINDS FOR TODAY ARE DUE TO A LEE TROUGH
THAT HAS DEVELOPED OVER CENTRAL COLORADO AND SOUTHEAST WYOMING. A
SHORTWAVE TROUGH WAS CURRENTLY LOCATED OVER THE FOUR CORNERS
REGION...HEADING TO THE NORTHEAST. SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED OVER THE ROCKY MOUNTAINS AHEAD OF THIS SHORTWAVE TROUGH.
FOR TONIGHT...AS THE SHORTWAVE MOVES CLOSER TO THE FORECAST
AREA...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE
FRONT RANGE AND MOVE TO THE EAST. A FEW OF THESE SHOWERS AND STORMS
MIGHT BE ABLE TO MAKE IT INTO NORTHEAST COLORADO...EXTREME NORTHWEST
KANSAS AND EXTREME SOUTHWEST NEBRASKA. ALL PRECIPITATION SHOULD
WEAKEN AND DISSIPATE AFTER DAYTIME HEATING IS LOST. SEVERE WEATHER
IS NOT EXPECTED AS DECREASING INSTABILITY THIS EVENING WILL MEAN
SHOWERS AND STORMS SHOULD BE ON A WEAKENING TREND AS THEY MOVE IN. A
PERSISTENCE FORECAST HAS BEEN USED FOR LOW TEMPERATURES TONIGHT WITH
LOWS POSSIBLY A DEGREE OR TWO WARMER. THERE COULD BE SOME PATCHY FOG
TONIGHT...HOWEVER WITH WINDS FROM THE SOUTH AT 5 TO 15 MPH ALL
NIGHT...THOUGHT THE THREAT FOR FOG WAS TOO LOW TO MENTION IN THE
FORECAST PACKAGE.
FOR TOMORROW...A BETTER CHANCE FOR THE ENTIRE REGION IS EXPECTED.
ANOTHER SHORTWAVE TROUGH WILL MOVE IN...A LITTLE EARLIER TOMORROW
THAN TODAY. A LEE TROUGH IS ALSO EXPECTED TO DEVELOP TO THE WEST AND
ENTER THE REGION BY TOMORROW AFTERNOON. AS THE SHORTWAVE AND LEE
TROUGH MOVE IN...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
AHEAD OF THE LEE TROUGH WHERE SURFACE CONVERGENCE IS MAXIMIZED. THIS
WILL LIKELY BE ALONG THE KANSAS...COLORADO BORDER WITH STORMS MOVING
IN A EAST TO NORTHEAST DIRECTION. A FEW STORMS WILL BE ABLE TO REACH
SEVERE LIMITS DUE TO SURFACE CAPE OF 2000-3000J/KG...LIFTED INDICES OF -6
TO -8 AND 850-500 MB LAPSE RATES OF 7 TO 8 C/KM. 0-6 KM BULK SHEAR
OF 15 TO 25 KTS AND WEAK FLOW ALOFT WOULD INDICATE THE POTENTIAL FOR
ORGANIZED SEVERE THUNDERSTORMS AS IN SUPERCELLS OR WELL ORGANIZED
MCS SYSTEMS ARE NOT LIKELY. INSTEAD...SLOW MOVING PULSE
THUNDERSTORMS WILL BE THE MOST LIKELY STORM MODE. ANY STORM THAT CAN
BECOME SEVERE WOULD BE CAPABLE OF LARGE HAIL AND DAMAGING WINDS. IN
ADDITION...HEAVY DOWNPOURS WITH THE POTENTIAL FOR FLASH FLOODING IN
LOCATIONS WITH SATURATED GROUND ARE POSSIBLE DUE TO THE SLOW
MOVEMENT AND HIGHER PRECIPITABLE WATER EXPECTED. HIGH TEMPERATURES
ARE FORECAST TO REACH THE UPPER 80S TO LOW 90S WITH SOUTH TO
SOUTHEAST WINDS CONTINUING DURING THE DAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 217 PM MDT SAT AUG 10 2013
SUNDAY NIGHT-TUESDAY...PATTERN WILL REMAIN SIMILAR TO THE CURRENT
PATTERN WITH LARGE H5 RIDGE AXIS OVER THE ROCKIES WITH LARGE TROUGH
REMAINING OVER THE GREAT LAKES. AT THE SFC...LOW CENTER OVER THE TRI
STATE AREA WILL GRADUALLY SHIFT TO THE SOUTH AS LARGE SFC HIGH MOVES
INTO THE PLAINS ON TUESDAY.
UNSETTLED WEATHER WILL CONTINUE THROUGH THE PERIOD WITH GENERALLY
LIGHT EASTERLY SFC FLOW...MODEST SFC TDS AND A SERIES OF WEAK PV
ANOMALIES MOVING THROUGH FLOW ALOFT PROVIDING CHANCES FOR
THUNDERSTORMS GENERALLY IN THE AFTERNOON AND EARLY EVENING THROUGH
THE PERIOD. ALTHOUGH PATTERN DOES LOOK FAVORABLE FOR CONTINUED
PRECIPITATION CHANCES...AM A LITTLE HESITANT TO GO MUCH HIGHER THAN
50 PERCENT PROBABILITIES THROUGH THE PERIOD AS HARD TO FIND A CLEAR
FOCUSING MECHANISM TO FAVOR ANY PARTICULAR AREA OVER THE OTHER. FOR
TEMPS...LOOKING AT PAST 7 TO 30 DAYS VERIFICATION LOOKS LIKE A
RATHER WARM BIAS HAS DEVELOPED IN SEVERAL DATASETS FOR LOW
TEMPERATURES AND HAVE BACKED TEMPERATURES DOWN SEVERAL DEGREES IN
RESPONSE. WITH EXPECTED SFC HIGH MOVING INTO THE AREA ON
TUESDAY...THINK POTENTIAL EXISTS FOR FAIRLY COOL TEMPS DURING THE
PERIOD. THAT BEING SAID...THERE STILL IS A RATHER LARGE DEGREE OF
SPREAD IN AVAILABLE DATA AND DID NOT LIMIT THE TEMPS AS MUCH AS
POSSIBLE.
IN THE EXTENDED (TUESDAY NIGHT-SATURDAY)...MEDIUM RANGE MODELS IN
GENERAL AGREEMENT WITH H5 RIDGE GRADUALLY AMPLIFYING THROUGH THE
PERIOD AND EAST COAST TROUGH GRADUALLY WEAKEN AS HEIGHT GRADIENT
DIMINISHES. WHILE PATTERN IS CHANGING SOMEWHAT...STILL HAS A LOT OF
SIMILARITIES TO ONGOING SET UP...WITH PRECIPITATION CHANCES
CONTINUING THROUGH MUCH OF THE PERIOD WITH POPS BEING WELL SUPPORTED
BY GEFS ENSEMBLE DATA. LATEST ECMWF DOES APPEAR A BIT MORE AGGRESSIVE
WITH AMPLIFYING RIDGE AND SHIFTING IT TO THE EAST...BUT OVERALL
DIFFERENCES APPEAR MINOR AT THIS POINT. TEMPERATURES WILL GRADUALLY
WARM INTO THE UPPER 80S BY NEXT WEEKEND WITH LOWS GENERALLY IN THE
UPPER 50S TO LOW 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 523 PM MDT SAT AUG 10 2013
VFR CONDITIONS WILL CONTINUE AT KGLD AND KMCK TONIGHT. THERE IS
ONLY A SLIGHT CHANCE OF STORMS THIS EVENING BUT CURRENT RADAR IS
FREE OF ANY RETURNS AND THE HRRR MODEL DOES NOT INDICATE ANYTHING
FOR KGLD AND KMCK. THERE IS ANOTHER CHANCE OF STORMS SUNDAY
AFTERNOON SO WILL INCLUDE VICINITY STORMS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...JRM
AVIATION...FS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
536 PM EDT Fri Aug 9 2013
...Forecast Update...
Issued at 533 PM EDT Fri Aug 9 2013
Updated the grids to reflect higher coverage of showers and storms
across SW portions of the CWA. Issued a Flood Advisory for areas
around Bowling Green as some training of showers and storms with
rainfall rates over 2 inches per hour at times will overspread the
area. Will need to watch for Flash Flood Warnings in the region over
the next couple of hours. Will also keep our eye on a cluster of
storms moving into the western fringes of our CWA in a couple of
hours. A few severe reports have come from the strongest storm,
however expect a weakening trend as the cluster moves in. Overall,
will mention numerous showers and storms early this evening in areas
where the biggest clusters are located, with isolated to scattered
coverage elsewhere. Please be aware that very heavy rainfall is
likely with any shower or storm and quick ponding of water on
roadways will occur.
.SHORT TERM (Now through Sunday)...
Issued at 305 PM EDT Fri Aug 9 2013
A line of showers and thunderstorms have begun to form along the
frontal boundary, currently draped along the Ohio River. As has been
the case this week, these are efficient rain producers, dumping a
lot of rain in a short amount of time. Traffic cameras in the
Louisville metro along with obs from SDF confirm the reduced
visibilities accompanying these cells. Thankfully, the line has been
moving relatively quickly off to the east-southeast so unless the
line really fills in, setting up a potential training effect,
flooding shouldn`t be a major concern, especially in north-central
KY where the rain has been much more hit and miss as of late. If it
is able to hold together and makes its way into the Bluegrass
region, there could be some localized problems since FFG is much
lower there due to the recent heavy rains and already saturated
soils. Unfortunately, the models aren`t handling it very well with
the exception of the latest NAM (but its performance this week has
been less than stellar) so its tough to get a solid idea of how this
will play out. While the HRRR doesn`t necessarily depict it well,
this has been one of the top performing models under this regime
and its showing scattered cells developing across much of the center
of the commonwealth. Later tonight, a mid-level wave traverses
through and the HRRR grabs onto it, bringing a cluster of showers
and embedded thunderstorms through northern KY and southern IN. This
may be a bit bullish but it would be the last hurrah for the
northern half of the forecast area as the boundary slowly sinks
south (assuming this scenario holds true).
By tomorrow, the focus for convection shifts to the south once again
along the quasi-stationary boundary. As it stands right now, any
storms that fire up during the heat of the day (despite the
continued cloud cover) should wane after sunset Saturday, allowing
for most of the area to remain dry. Under light to calm winds and
lingering low-level moisture, patchy fog could be a factor for not
only tonight (wherever it doesn`t rain) but for tomorrow night as
well. Overnight lows for both nights will range from the upper 60s
to the lower 70s from north to south, respectively. Under the
aforementioned cloud cover, highs tomorrow will again be below
normal, primarily in the mid 80s. Expect this tropical-feeling
airmass to remain in place for the entirety of this forecast period.
.LONG TERM (Sunday night through Friday)...
Issued at 312 PM EDT Fri Aug 9 2013
The start of the long term period will feature generally zonal upper
flow, which will transition to an eastern trough/western ridge by
the end of the long term period. This pattern shift will allow for
drier conditions and cooler/less humid air by the middle of next
week.
A quasi-stationary frontal boundary will be draped from southwest to
northeast across southern Kentucky on Sunday. This will serve as
the focus for showers and thunderstorms to continue, mainly across
southern Kentucky as a shortwave trough rides along the boundary and
brings enhanced vertical motion. As winds turn northerly across
southern Indiana and northern Kentucky due to incoming high
pressure, think enough dry air will work in to actually keep much of
Sunday dry for those regions.
On Sunday night, the surface high will scoot east as another
shortwave trough dives through the Great Lakes region. Guidance
suggests this wave will pull the quasi-stationary front back north
which would give much more of central and northern KY decent
rainfall chances. However, am a bit skeptical of this solution as
the progged system does not appear strong enough to force the front
northward (especially if it`s continually being convectively
reinforced further south). Therefore, the more widespread activity
will likely remain across southern KY, with a general lull in
activity across northern KY and southern Indiana. Given the
continued moist atmosphere south of the front, localized flooding
will need to continue to be watched especially if areas receive
heavy rainfall through the short term period.
By Monday night into Tuesday, another surface front will approach
from the northwest. This front looks much more progressive as the
upper-level flow begins to transition to more northwesterly. As
mentioned in the previous discussion, am a bit skeptical on just how
much moisture will remain ahead of this secondary front, thus will
continue with 30-40 pops as it passes through on Tuesday. Given
the likely moist bias in guidance, instability along this front will
be less than currently progged, thus do not expect severe weather.
However, the drier air working in will help support a few healthy
downdrafts, which may lead to some sub-severe gusts in the
heavier storm cores.
The front will clear the region by Tuesday night, allowing Canadian
high pressure to build into the Ohio Valley. This will bring
welcomed relief from the muggy airmass we have seen of late, as
temperatures fall into the upper 70s/lower 80s with dewpoints in the
50s and lower 60s. This pleasant airmass will also get rid of any
additional storm potential, with dry weather expected Wednesday
through at least the end of next week.
&&
.AVIATION (18Z TAF Update)...
Issued at 128 PM EDT Fri Aug 9 2013
Current radar imagery depicts a line of storms attempting to form
along the stationary boundary draped along the Ohio River. If this
line develops, SDF will be the first to see the impacts this
afternoon and if it is able to hold together, LEX could see some
activity in the area early this evening. With the atmosphere
remaining in its warm, moist, and unstable state, showers and
thunderstorms could pop-up wherever a trigger can be found (i.e. the
frontal boundary). Satellite imagery has shown partial clearing in
southern portions of the commonwealth, particularly around the BWG
terminal. Allowing the sun to peak through will increase daytime
heating in that area, allowing for the potential for thunderstorms
to pop-up in the vicinity. Any afternoon showers and thunderstorms
that develop should wane after sunset as the focus for triggering
then shifts to a mid-level wave traversing through overnight. At
this point, confidence is too low as coverage looks to remain
minimal, if at all overnight. Where confidence is a bit higher is
with respect to the low cloud deck and at least MVFR BR impacts to
all three terminals overnight, especially closer to the pre-dawn
hours. As the front slowly moseys southward, a renewed chance for
convection could impact BWG and potentially LEX but the threat looks
to be south of SDF by tomorrow. Challenging forecast to say the
least as the Ohio Valley remains locked in this tropical-like
pattern through early this weekend.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........BJS
Short Term.....LG
Long Term......KJD
Aviation.......LG
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
314 PM EDT Fri Aug 9 2013
.SHORT TERM (Now through Saturday Night)...
Issued at 305 PM EDT Fri Aug 9 2013
A line of showers and thunderstorms have begun to form along the
frontal boundary, currently draped along the Ohio River. As has been
the case this week, these are efficient rain producers, dumping a
lot of rain in a short amount of time. Traffic cameras in the
Louisville metro along with obs from SDF confirm the reduced
visibilities accompanying these cells. Thankfully, the line has been
moving relatively quickly off to the east-southeast so unless the
line really fills in, setting up a potential training effect,
flooding shouldn`t be a major concern, especially in north-central
KY where the rain has been much more hit and miss as of late. If it
is able to hold together and makes its way into the Bluegrass
region, there could be some localized problems since FFG is much
lower there due to the recent heavy rains and already saturated
soils. Unfortunately, the models aren`t handling it very well with
the exception of the latest NAM (but its performance this week has
been less than stellar) so its tough to get a solid idea of how this
will play out. While the HRRR doesn`t necessarily depict it well,
this has been one of the top performing models under this regime
and its showing scattered cells developing across much of the center
of the commonwealth. Later tonight, a mid-level wave traverses
through and the HRRR grabs onto it, bringing a cluster of showers
and embedded thunderstorms through northern KY and southern IN. This
may be a bit bullish but it would be the last hurrah for the
northern half of the forecast area as the boundary slowly sinks
south (assuming this scenario holds true).
By tomorrow, the focus for convection shifts to the south once again
along the quasi-stationary boundary. As it stands right now, any
storms that fire up during the heat of the day (despite the
continued cloud cover) should wane after sunset Saturday, allowing
for most of the area to remain dry. Under light to calm winds and
lingering low-level moisture, patchy fog could be a factor for not
only tonight (wherever it doesn`t rain) but for tomorrow night as
well. Overnight lows for both nights will range from the upper 60s
to the lower 70s from north to south, respectively. Under the
aforementioned cloud cover, highs tomorrow will again be below
normal, primarily in the mid 80s. Expect this tropical-feeling
airmass to remain in place for the entirety of this forecast period.
.LONG TERM (Sunday through Friday)...
Issued at 312 PM EDT Fri Aug 9 2013
The start of the long term period will feature generally zonal upper
flow, which will transition to an eastern trough/western ridge by
the end of the long term period. This pattern shift will allow for
drier conditions and cooler/less humid air by the middle of next
week.
A quasi-stationary frontal boundary will be draped from southwest to
northeast across southern Kentucky on Sunday. This will serve as
the focus for showers and thunderstorms to continue, mainly across
southern Kentucky as a shortwave trough rides along the boundary and
brings enhanced vertical motion. As winds turn northerly across
southern Indiana and northern Kentucky due to incoming high
pressure, think enough dry air will work in to actually keep much of
Sunday dry for those regions.
On Sunday night, the surface high will scoot east as another
shortwave trough dives through the Great Lakes region. Guidance
suggests this wave will pull the quasi-stationary front back north
which would give much more of central and northern KY decent
rainfall chances. However, am a bit skeptical of this solution as
the progged system does not appear strong enough to force the front
northward (especially if it`s continually being convectively
reinforced further south). Therefore, the more widespread activity
will likely remain across southern KY, with a general lull in
activity across northern KY and southern Indiana. Given the
continued moist atmosphere south of the front, localized flooding
will need to continue to be watched especially if areas receive
heavy rainfall through the short term period.
By Monday night into Tuesday, another surface front will approach
from the northwest. This front looks much more progressive as the
upper-level flow begins to transition to more northwesterly. As
mentioned in the previous discussion, am a bit skeptical on just how
much moisture will remain ahead of this secondary front, thus will
continue with 30-40 pops as it passes through on Tuesday. Given
the likely moist bias in guidance, instability along this front will
be less than currently progged, thus do not expect severe weather.
However, the drier air working in will help support a few healthy
downdrafts, which may lead to some sub-severe gusts in the
heavier storm cores.
The front will clear the region by Tuesday night, allowing Canadian
high pressure to build into the Ohio Valley. This will bring
welcomed relief from the muggy airmass we have seen of late, as
temperatures fall into the upper 70s/lower 80s with dewpoints in the
50s and lower 60s. This pleasant airmass will also get rid of any
additional storm potential, with dry weather expected Wednesday
through at least the end of next week.
&&
.AVIATION (18Z TAF Update)...
Issued at 128 PM EDT Fri Aug 9 2013
Current radar imagery depicts a line of storms attempting to form
along the stationary boundary draped along the Ohio River. If this
line develops, SDF will be the first to see the impacts this
afternoon and if it is able to hold together, LEX could see some
activity in the area early this evening. With the atmosphere
remaining in its warm, moist, and unstable state, showers and
thunderstorms could pop-up wherever a trigger can be found (i.e. the
frontal boundary). Satellite imagery has shown partial clearing in
southern portions of the commonwealth, particularly around the BWG
terminal. Allowing the sun to peak through will increase daytime
heating in that area, allowing for the potential for thunderstorms
to pop-up in the vicinity. Any afternoon showers and thunderstorms
that develop should wane after sunset as the focus for triggering
then shifts to a mid-level wave traversing through overnight. At
this point, confidence is too low as coverage looks to remain
minimal, if at all overnight. Where confidence is a bit higher is
with respect to the low cloud deck and at least MVFR BR impacts to
all three terminals overnight, especially closer to the pre-dawn
hours. As the front slowly moseys southward, a renewed chance for
convection could impact BWG and potentially LEX but the threat looks
to be south of SDF by tomorrow. Challenging forecast to say the
least as the Ohio Valley remains locked in this tropical-like
pattern through early this weekend.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........LG
Long Term.........KJD
Aviation..........LG
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
139 AM EDT Fri Aug 9 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1145 PM EDT Thu Aug 8 2013
One more quick update to match up areas of rain on 88D with the
forecast. Theta-E ridge axis now is focused along where the new
cells are developing in our southwest forecast area. Storms farther
north are progressing east nicely, limiting rainfall totals for now.
Issued at 944 PM EDT Thu Aug 8 2013
Did another quick update to increase PoP chances across southern
Indiana and far northern Kentucky for later this evening. Cluster
of ongoing showers and storms across southern Indiana is drifting a
little more southward now, with some backbuilding on the
southwestern flank. Extrapolated radar imagery suggests that this
could clip areas all the way south toward the Ohio River later this
evening. These showers and storms could affect the Louisville Metro
area around midnight EDT.
Secondary cluster of storms across northwest TN continues to trek
northeastward and is showing signs of gusting out to the northeast.
If these storms hold together, they could affect far southern
Kentucky after midnight as well.
Not much development off to the west at this time. However, latest
data continues to suggest that additional storms may develop to our
west and then head through central Kentucky overnight. It appears
that the models may be trying to develop convection in associated
with the nocturnal low-level jet axis. For now, have backed off
PoPs slightly in central Kentucky until after midnight and then have
let PoPs ramp up late. Rest of the forecast elements look good at
this time.
Update issued at 820 PM EDT Thu Aug 8 2013
Did a quick update to scale back precipitation chances for the next
few hours across much of Kentucky. Vorticity lobe continues to trek
eastward across Indiana this evening. Convection along the southern
edge of this boundary never really moved southward...but rather
eastward and looks to stay along and north of the I-64 corridor for
the next few hours. The best chances of rainfall in the near term
will be across our north edges of southern Indiana counties.
Secondary cluster of strong thunderstorms has rapidly intensified
across far eastern Arkansas and west Tennessee. This activity
continues to trek eastward and may affect the extreme southern
portions of our area toward the late evening hours. Additional
storms across east-central MO/IL are trying to develop. Latest
model data suggests this activity will further develop this evening
and then push into the region overnight. Will continue to go with
the higher PoPs for the later overnight period, but continue to
monitor the latest convective trends throughout the evening.
Update issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (06Z TAF Update)...
Issued at 135 AM EDT Fri Aug 9 2013
Forecast remains lower confidence, given that timing of showers and
storms still is dependent on small scale features. The near term
forecast is relatively straightforward, but rains are all close to
the terminals, but not directly affecting them at this time. Best
growth appears to be along a line from just north of KBWG to south
of KFTK. Still think KBWG has a chance to get in on these storms
over the next few hours, with KLEX a couple hours downstream. In the
juicy atmosphere, showers can develop at almost any time, so have
left in the chance at KSDF as well. Some drier air will try and work
in from the north, slowly, which should limit coverage at KSDF by
mid morning and then by late in the day at KLEX. The actual front
that has been stalled to our north may make it to KSDF/KLEX this
evening, so have variable winds for now.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Updates........RJS/MJ
Short Term.....JSD
Long Term......lg
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
401 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFFSHORE INTO THE WEEKEND...USHERING WARM
AND HUMID CONDITIONS INTO THE REGION. A COLD FRONT WILL SLOWLY
APPROACH FROM THE NORTHWEST FRIDAY INTO SATURDAY...EVENTUALLY
STALLING OVER NORTH CAROLINA ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS FEATURES A STRONG UPPER LOW SPINNING JEST
WEST OF ST JAMES BAY IN NORTHERN ONTARIO, WITH THE ASSOCIATED SFC
LOW OVER EASTERN QUEBEC. THE ATTENDANT SFC COLD FRONT EXTENDS
FROM UPSTATE NY BACK INTO THE LOWER OH VALLEY. ALOFT, FLAT W-SW
FLOW PREVAILS, IN BETWEEN STRONG HIGH PRESSURE JUST OFF THE
SOUTHEAST COAST AND STRONG UPPER LOW OVER NORTHERN CANADA. THIS
W-SW FLOW CONTINUES TO ADVECT MOISTURE DOWNSTREAM FROM A CONVOY
OF WEAK SHORTWAVE DISTURBANCES MOVING ALONG THE STALLED BOUNDARY.
PW VALUES REMAIN ~2.00 OVER THE MID- ATLANTIC REGION...AND SOLIDLY
IN THE 2-2.25" RANGE JUST WEST OF THE CENTRAL APPALACHIANS). SOME
SHOWERS PERSIST ALONG AND JUST W-NW OF THE AKQ CWA...LARGELY A
RESULT OF THE VERY MOIST AIRMASS. HOWEVER, VERY LITTLE IN THE WAY
OF AREAL COVERAGE THUS FAR OVER OUR REGION, WITH REGIONAL RADAR
REVEALING A MAJORITY OF THE ACTIVITY STILL WELL BACK NW FROM THE
OHIO VALLEY INTO CENTRAL PA AND THE NY HUDSON VALLEY.
FOR TODAY...
UPPER LOW JUST SOUTH OF HUDSON BAY WILL SLOWLY EDGE EWD TODAY
ACROSS THE ST LAWRENCE VALLEY OF QUEBEC. MEANWHILE, UPPER RIDGE
WILL AMPLIFY OFFSHORE OF THE SE CONUS. THIS WILL MAINTAIN MOIST
W-SW FLOW THROUGH THE DAY...BRINGING CONTINUED WARM AND HUMID
CONDITIONS. REGARDING PRECIPITATION CHANCES, WITH THE FRONT
ROUGHLY PARALLEL TO THE MID-UPPER FLOW, IT WILL CONTINUE TO MAKE
VERY SLOW EASTWARD PROGRESS TODAY. THUS, THE LOCAL AREA WL REMAIN
SEPARATED FROM THE MAIN AREA OF BROAD SCALE FORCING. HOWEVER, THE
WEST/DOWNSLOPE FLOW ALOFT WL AID IN THE DEVELOPMENT OF A PIEDMONT
LEE TROUGH, WHICH SHOULD BE THE FOCUS FOR A BIT MORE IN THE WAY OF
CONVECTIVE DEVELOPMENT THAN WE`VE SEEN THE PAST FEW DAYS. MAJORITY
OF THE ACTIVITY WILL REMAIN TO OUR NW. STILL, HRRR DOES FIRE UP
SOME CONVECTION ALONG A LLVL CONVERGENCE BOUNDARY...AND HV PRESERVED
HIGHEST POPS OUT THAT WAY, WITH LOWER POPS BACK TOWARD THE COASTAL
PLAIN. WL GO WITH A LOW END LIKELY POP OVER THE FAR NW, DROPPING
BACK TO A 30-50% POP FOR MUCH OF THE AREA BY MID AFTN. BEST RAIN
CHANCES ORIENTED NW OF A FARMVILLE-RICHMOND-CAMBRIDGE MD LINE.
FOR HIGHS, DESPITE PLENTY OF CLOUD COVER AND A RATHER MOIST
AIRMASS, INCREASING HEIGHTS COURTESY OF AMPLIFYING RIDGE SHOULD
ALLOW TEMPS TO RISE A DEGREE OR TWO FROM THOSE OF THURSDAY. HIGHS
GENERALLY IN THE LOWER 90S INLAND, UPPER 80S TO AROUND 90 COASTAL
AREAS.
TONIGHT...
GIVEN GENERALLY WEAK DYNAMICS, EXPECT MAJORITY OF CONVECTIVE
ACTIVITY TO WANE QUICKLY IN COVERAGE/INTENSITY WITH LOSS OF
HEATING/NOCTURNAL STABILITY. STILL, AS WE`VE SEEN THIS MORNING,
DOESN`T TAKE MUCH TO YIELD A FEW SHRAS IN AN AIRMASS THIS
MOIST...SO WILL RETAIN 30-40 POP FOR SCT SHRAS OVERNIGHT.
OTHERWISE A MOSTLY CLOUDY/MUGGY NIGHT IS EXPECTED WITH LOWS IN THE
LOW TO MID 70S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
COLD FRONT WILL CONTINUE ITS VERY SLOW MOVEMENT SWWD TOWARDS THE
NRN MID ATLANTIC SAT...STRETCHING SWWD INTO THE MID MS VALLEY. AS
WE`VE SEEN THIS MORNING, WL SEE SEVERAL WAVES DEVELOP AND TRAIN ALONG
THE FRONTAL ZONE ON SAT AS SHORTWAVE ENERGY TRAVERSES THE W-SWLY
FLOW ALOFT. WILL HAVE HIGH END LIKELY POPS WEST OF THE CHES BAY
AS MID LEVEL SHORTWAVE ENERGY AND RRQ OF +70KT JET WL PROVIDE
NEEDED FORCING FOR ASCENT OVER THESE AREAS. HIGHLY ANOMALOUS
PRECIP WATER VALUES (+2 S.D.) AND CONTINUED MID-UPPER FLOW
PARALLEL TO THE SLOWLY SAGGING FRONT WILL INCREASE THE LIKELIHOOD
FOR SLOW MOVING STORMS AND LOCALLY HEAVY RAINFALL OVER THE
AREA...AND WL UPDATE TO MENTION HEAVY RAIN IN THIS MORNING`S HWO
IN ASSOCIATION WITH THIS EXPECTATION. LATEST DATA DOES CLEAR
NORTHERN ZONES BY SAT NIGHT, BUT EXPECT THAT THE FRONT WILL BECOME
STALLED ALONG/JUST NORTH OF THE VA/NC BORDER SAT NGT DUE TO
AFOREMENTIONED PARALLEL FLOW. ACCORDINGLY...KEPT POPS AT HIGH END
CHC (40-50%) ACROSS THE SOUTHERN TWO-THIRDS OF THE CWA SAT NIGHT
FOR CONTINUED SHRAS/TSTMS...WITH LOCALLY HVY RAINFALL REMAINING A
CONCERN INTO SUN MORN.
FOR TEMPS, EXPECT ANOTHER DAY OF ABOVE NORMAL TEMPS SAT (UPR
80S/LOW 90S INLAND...U80S AT THE COAST). MILD OVERNIGHT/EARLY
MORNING LOWS DUE TO MUGGY CONDITIONS AND PERIODS OF CLOUDS. LOWS
70-75.
SUNDAY...
00Z MODELS STALL THE SFC FRONT OVER NC ON SUNDAY. THE QUESTION
STILL REMAINS IS JUST HOW MUCH PCPN WILL LINGER ACROSS OUR CWA.
THE 12Z ECMWF LIMITS PCPN TO FAR SOUTHERN VA AND NE NC (GENERALLY
SOUTH OF THE VA HWY-58 CORRIDOR). MEANWHILE...THE 0Z GFS SHOWS A
STRONGER WAVE OF LOW PRESSURE DEVELOPING ALONG THE FRONT WHICH
BRINGS PCPN BACK INTO CENTRAL VA. BASED ON THE UNCERTAINTY...WILL
NOT SHUNT PCPN CHANCES AS FAR SOUTH AS THE SREF/ECMWF WOULD
SUGGEST...INSTEAD CARRING CHC POP/SCT T (30-50%) FOR ALL BUT THE MD
EASTERN SHORE INTO SUNDAY NIGHT. CONTINUED WARM AND HUMID WITH
HIGHS IN THE 80S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
PATTERN NEXT WEEK WILL ALLOW FOR CONTINUED CHCS FOR SHRAS/TSRAS.
LONG TERM PERIOD STARTS OFF MON WITH CHCS FOR RAIN (30-40%) ALONG A
STALLED FRONTAL BOUNDARY OVER/JUST SOUTH OF THE LOCAL AREA. ZONAL FLOW
ALOFT WILL PREVENT THE FRONT FROM PUSHING SE OF THE AREA ERLY IN THE
WEEK...AND WITH CONTINUED DEEP MOISTURE THE CHC FOR RAIN WILL
CONTINUE INTO TUE DESPITE MARGINAL FORCING (MID-LVL ENERGY). AN
UPR-LVL TROF DIGS OVER THE ERN CONUS MID TO LATE WEEK AND FINALLY
FORCES THE FRONT OFFSHORE AS THE TROF PULLS OFF TO THE EAST.
TEMPS THRU THE PERIOD WILL AVG NEAR TO SLIGHTLY BELOW NORMAL...WITH
HIGHS RANGING THRU THE 80S AND LOWS IN THE 60S TO LWR 70S.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
SOUTH WINDS AROUND 5 KT HAVE KEPT THE LOWER ATMOSPHERE WELL-MIXED
AND WILL PREVENT ANY FOG FROM DEVELOPING TWD DAYBREAK. A LEE
TROUGH DEVELOPS OVER THE AREA TODAY AS A COLD FRONT IN THE OHIO
VALLEY APPROACHES THE MID ATLANTIC REGION. THIS TROUGH WILL
TIGHTEN THE PRESSURE GRADIENT AND ALSO PROVIDE A FOCUS FOR SHOWERS
AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING. REGARDING
WINDS...SOUTH WINDS WILL BECOME BREEZY BY MID MORNING WITH GUSTS
OF 20-25 KT KICKING IN BY LATE MORNING/EARLY AFTERNOON. REGARDING
THUNDERSTORMS...MODERATE TO HEAVY RAINFALL AND LOCALIZED STRONG
WIND GUSTS WILL BE THE MAIN IMPACTS. SHOWERS AND STORMS WILL
DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT WITH SOME STRAGGLING
SHOWERS POSSIBLE CLOSER TO THE COAST BY SATURDAY MORNING.
THE FRONT STALLS OVER SE VA ON SATURDAY...FOCUSING AFTERNOON
THUNDERSTORM ACTIVITY OVER THE SRN HALF OF VA AND NE NC INTO
SATURDAY EVENING. FOR SUNDAY INTO NEXT WEEK...THE STALLED FRONT
GRADUALLY PUSHES SOUTH OF THE AREA...HOWEVER PERIODS OF UNSETTLED
WEATHER SHOULD STILL BE ANTICIPATED AS MOISTURE AND ENERGY RIDE
ALONG THIS BOUNDARY.
&&
.MARINE...
A SFC TROUGH DEVELOPS BY THIS AFTN AHEAD OF AN APPROACHING COLD
FRONT. THIS FEATURE WILL CAUSE THE PRESSURE GRADIENT TO TIGHTEN AND
WILL ALSO PROVIDE A FOCUS FOR SHOWERS AND THUNDERSTORMS DURING THIS
AFTN AND EVENING. SOUTH WINDS THIS MORNING WILL TURN TO THE
SOUTHWEST BY THIS AFTERNOON AND AVERAGE 10-15 KT. GUSTS MAY REACH
20 KT AT TIMES OVER AREA WATERS (POSSIBLY UP TO 25 KT OUT NEAR
20 NM)...HOWEVER CONFIDENCE IS NOT HIGH ENOUGH TO ISSUE LOW-END SCA
FLAGS WITH THIS MORNING`S FORECAST ISSUANCE. WILL NEED TO MONITOR
TRENDS AS THE DAY UNFOLDS. REGARDLESS...LOCALLY STRONG WIND GUSTS
SHOULD BE ANTICIPATED IN THE VICINITY OF THUNDERSTORMS TODAY IN
ADDITION TO MODERATE TO HEAVY RAINFALL. SCA MAY BE POSSIBLE
OVERNIGHT TONIGHT INTO EARLY SATURDAY MORNING...BUT WILL BE HIGHLY
DEPENDENT ON CLOUD COVER AND PRECIPITATION COVERAGE (BOTH OF WHICH
CAN HAMPER MIXING STRONGER WINDS ALOFT TO THE SFC). AGAIN...WILL
NEED TO MONITOR THROUGH TODAY. WAVE HEIGHT MODELS HAVE BEEN OVERDONE
LATELY...THEREFORE SEAS FOR TODAY AND TONIGHT HAVE BEEN CAPPED AT
4 FT. EXPECT WAVES ON CHES BAY TO AVERAGE 2-3 FT DURING THIS SAME
TIME FRAME.
THE FRONT STALLS OVER SE VA/NE NC ON SATURDAY AND WILL FOCUS AFTN
THUNDERSTORM ACTIVITY OVER SRN WATERS...INCLUDING SRN CHES BAY AND
COASTAL WATERS SOUTH OF PARRAMORE ISLAND. THE STALLED FRONT
GRADUALLY PUSHES SOUTH OF THE WATERS FROM SUNDAY INTO NEXT WEEK...
HOWEVER PERIODS OF UNSETTLED WEATHER SHOULD STILL BE ANTICIPATED AS
MOISTURE AND ENERGY RIDE ALONG THIS BOUNDARY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDM
NEAR TERM...MAM
SHORT TERM...JDM/MAM
LONG TERM...MAS
AVIATION...BMD
MARINE...BMD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
141 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONT CURRENTLY ACROSS THE EASTERN GREAT LAKES WILL
CONTINUE TO TRIGGER SHOWERS AND SOME THUNDERSTORMS OVERNIGHT AND
INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FOR THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS AND THUNDERSTORMS HAVE DIMINISHED ACROSS THE REGION EARLY
THIS MORNING. HOWEVER...ANOTHER ROUND OF CONVECTION OVER
SOUTHWESTERN OHIO THAT`S TIED TO AN UPPER LEVEL SHORTWAVE WILL
CONTINUE TO MOVE EASTWARD OVER THE NEXT COUPLE OF HOURS. MANY OF
THE HI RES MODELS SUGGEST THAT ADDITIONAL SHOWERS AND
THUNDERSTORMS COULD BE REINVIGORATED AS THIS SHORTWAVE INTERACTS
WITH THE BOUNDARY THAT REMAINS JUST ALONG THE NORTHERN PERIPHERY
OF OUR FORECAST AREA. FOR NOW...DIMINISHED POPS FOR MUCH OF THE
AREA EAST OF THE OH/PA BORDER. THEN...WILL BRING IN LIKELY POPS INTO OUR
OHIO COUNTIES AS THIS AREA OF CONVECTION APPROACHES. TIMED THIS
BASED ON THE NAM AND HRRR WHICH LINED UP QUITE WELL WITH CURRENT
RADAR OBS.
CURRENT MESOSCALE ANALYSIS INDICATES PWAT VALUES NEAR 2 INCHES
OVER SOUTHERN OHIO EARLY THIS MORNING. WILL CONTINUE TO MONITOR
FOR ANY FLOODING CONCERNS ALTHOUGH EXPECT THIS TO REMAIN MORE OF A
LOCALIZED PROBLEM VS WIDESPREAD.
TEMPERATURES WILL REMAIN ELEVATED OVERNIGHT WITH PLENTY OF CLOUD
COVER PRESENT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
THE CDFNT SHOULD SINK SLOWLY SWD ACRS THE AREA FRI. A SHRTWV AND
AREA OF DEEPER MOISTURE SHOULD ENHANCE SHWR CHCS AS WELL. MDL
PROGS SHOW LMTD INSTBY FRI SO SVR WEA THREAT IS LOW...HOWEVER
PWATS WL BE ELEVATED. DO NOT THINK THREAT FOR FLOODING IS WDSPRD
ENOUGH FOR A FLOOD WATCH ATTM...BUT DID MENTION PSBL LOCALIZED
FLOODING IN THE HWO. WL MONITOR. SHWR/TSTM CHCS SHOULD BE DCRG FM
N-S LT FRI THRU SAT AS THE CDFNT PUSHES S OUT OF THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
BEST CHANCE FOR SHOWERS IN THE EXTENDED WILL BE TUESDAY AS A
SECONDARY COLD FRONT CROSSES THE REGION. RAISED POPS TO CHANCE
WITH THIS SYSTEM AS MODELS AGREE ON MORE AVAILABLE MOISTURE.
OTHERWISE HIGH PRESSURE DOMINATES INTO LATE WEEK WITH TEMPERATURES
BELOW AVERAGE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
A WIDE RANGE OF CIGS AND VSBY AT 06Z AS SHOWERS HAVE DIMINISHED.
LOW LEVEL MOISTURE AND WEAK FLOW WILL ALLOW MVFR TO IFR AT TIMES
UNTIL STRONGER SHORTWAVE APPROACHES FORM LOWER OHIO VALLEY TOWARD
DAYBREAK. WENT WITH ABOUT A 6 HOUR PERIOD OF IFR CIGS AND MVFR
IN SHOWERS AS SHORTWAVE MOVES AHEAD OF FRONT. EXPECT FROPA TOWARD
MID AFTERNOON WITH IMPROVING CONDITIONS TO VFR LATE TODAY AND
TONIGHT. WINDS WILL BECOME WEST THIS AFTERNOON BECOME NORTHWEST
THIS EVENING UNDER 10 KTS.
OUTLOOK.../SATURDAY THROUGH TUESDAY/... GENERAL VFR FOR THE WEEKEND
INTO MONDAY. A COLD FRONT WILL BRING POSSIBLE RESTRICTIONS
TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
109 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONT CURRENTLY ACROSS THE EASTERN GREAT LAKES WILL
CONTINUE TO TRIGGER SHOWERS AND SOME THUNDERSTORMS OVERNIGHT AND
INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FOR THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS AND THUNDERSTORMS HAVE DIMINISHED ACROSS THE REGION EARLY
THIS MORNING. HOWEVER...ANOTHER ROUND OF CONVECTION OVER
SOUTHWESTERN OHIO THAT`S TIED TO AN UPPER LEVEL SHORTWAVE WILL
CONTINUE TO MOVE EASTWARD OVER THE NEXT COUPLE OF HOURS. MANY OF
THE HI RES MODELS SUGGEST THAT ADDITIONAL SHOWERS AND
THUNDERSTORMS COULD BE REINVIGORATED AS THIS SHORTWAVE INTERACTS
WITH THE BOUNDARY THAT REMAINS JUST ALONG THE NORTHERN PERIPHERY
OF OUR FORECAST AREA. FOR NOW...DIMINISHED POPS FOR MUCH OF THE
AREA EAST OF THE OH/PA BORDER. THEN...WILL BRING IN LIKELY POPS INTO OUR
OHIO COUNTIES AS THIS AREA OF CONVECTION APPROACHES. TIMED THIS
BASED ON THE NAM AND HRRR WHICH LINED UP QUITE WELL WITH CURRENT
RADAR OBS.
CURRENT MESOSCALE ANALYSIS INDICATES PWAT VALUES NEAR 2 INCHES
OVER SOUTHERN OHIO EARLY THIS MORNING. WILL CONTINUE TO MONITOR
FOR ANY FLOODING CONCERNS ALTHOUGH EXPECT THIS TO REMAIN MORE OF A
LOCALIZED PROBLEM VS WIDESPREAD.
TEMPERATURES WILL REMAIN ELEVATED OVERNIGHT WITH PLENTY OF CLOUD
COVER PRESENT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
THE CDFNT SHOULD SINK SLOWLY SWD ACRS THE AREA FRI. A SHRTWV AND
AREA OF DEEPER MOISTURE SHOULD ENHANCE SHWR CHCS AS WELL. MDL
PROGS SHOW LMTD INSTBY FRI SO SVR WEA THREAT IS LOW...HOWEVER
PWATS WL BE ELEVATED. DO NOT THINK THREAT FOR FLOODING IS WDSPRD
ENOUGH FOR A FLOOD WATCH ATTM...BUT DID MENTION PSBL LOCALIZED
FLOODING IN THE HWO. WL MONITOR. SHWR/TSTM CHCS SHOULD BE DCRG FM
N-S LT FRI THRU SAT AS THE CDFNT PUSHES S OUT OF THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
HIGH PRES WL SETTLE OVR THE GT LKS AND OH VLY RGN THRU MUCH OF THE
PD. THE ONLY EXCEPTION WL BE A WK CDFNT CROSSING THE AREA ON TUE.
MOISTURE IS LMTD WITH THIS FNT SO ONLY SLGT CHC POPS IN THE FCST.
TEMPS SHOULD AVG A LTL BLO SEASONAL AVGS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
MORE RESTRICTIONS...MAINLY MVFR AND POSSIBLY IFR...CAN BE EXPECTED
TNGT IN THE FORM OF SHWRS...ST AND FOG GIVEN THE POOLING MSTR
ALNG...AND IN ADVN OF FRONTAL BNDRY.
OUTLOOK.../FRIDAY THROUGH TUESDAY/...
MORE SHWRS AND TSTMS ARE ANTICIPATED ALNG THE FRONT ON FRI. GENL
VFR WL DLVP THIS WEEKEND IN THE WAKE OF THE SWD PROGRESSING FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 PM EDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED SEVERAL WEAK SHORTWAVES
ROTATING AROUND A MID/UPPER LEVEL LOW OVER NRN ONTARIO. SCT/ISOLD
-SHRA PERSISTED MAINLY ACROSS THE SRN CWA SUPPORTED BY A WEAK
850-700 MB TROUGH AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A
115 KNOT 300 MB JET TO THE NE OF LAKE SUPERIOR. A SHORTWAVE TROUGH
NW OF LAKE SUPERIOR ALSO SUPPORTED SOME ISOLD/SCT SHOWERS OVER NW
ONTARIO FROM SIOUX LOOKOUT TO DRYDEN.
TODAY...RADAR/SATELLITE TRENDS AND SHORT RANGE MODELS SUGGEST THAT
THE SHOWERS EARLY THIS MORNING WILL DEPART TO THE EAST OF THE CWA BY
AROUND 12Z. ALTHOUGH THE STRONGER 700-500 MB QVECTOR CONV ASSOCIATED
WITH THE NW ONTARIO SHRTWV WILL REMAIN NORTH OF UPPER MICHIGAN...THE
TAIL OF THIS FEATURE COMBINED WITH LOW LEVEL CONV ALONG THE LAKE
SUPERIOR BREEZE BOUNDARY AND MINIMAL MLCAPE VALUES TO NEAR 200 J/KG
IS EXPECTED TO GENERATE ISOLD -SHRA OVER INLAND PORTIONS OF
EAST CNTRL UPPER MICHIGAN. SOME -SHRA MAY ALSO BE POSSIBLE FARTHER
WEST FROM ESC-IMT ALONG A WEAK SFC TROUGH BUT CONFIDENCE WAS LOWER
SO PCPN WAS NOT MENTIONED AT THIS TIME. OTHERWISE...850 MB TEMPS
FROM 7C-9C WILL SUPPORT SCT/BKN CU DEVELOPMENT WITH CONTINUED BELOW
NORMAL HIGHS IN THE UPPER 60S AND LOWER 70S ARE EXPECTED.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND HIGH PRES BUILDING
INTO THE REGION...CLEARING SKIES AND DIMINISHING WINDS WILL LEAD TO
FAVORABLE RADIATIONAL COOLING CONDITIONS OVERNIGHT. SO...KEPT FCST
MINS CLOSER TO THE LOWER END OF GUIDANCE...WITH READINGS INTO THE
LOWER TO MID 40S INLAND AND IN THE LOWER 50S ALONG THE GREAT LAKES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EDT FRI AUG 9 2013
OTHER THAN A PERIOD OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS
SUNDAY AFTERNOON INTO MONDAY MORNING...A RATHER EXTENDED PERIOD OF
DRY WEATHER IS EXPECTED WITH SLIGHTLY BELOW NORMAL TEMPERATURES
THROUGH MUCH OF NEXT WEEK.
SATURDAY...DRY AIR WILL CONTINUE TO FILTER IN EARLY IN THE MORNING
AS A REINFORCING SFC HIGH AND WEAK RIDGING MOVE IN FROM THE WEST.
THERE HAS BEEN SOME HINT AT ISOLATED DIURNAL SHOWERS FORMING ACROSS
INTERIOR LOCATIONS BY BOTH THE NAM AND THE GFS OFF AND ON OVER THE
PAST TWO DAYS. INVESTIGATION OF FORECAST SOUNDINGS ACROSS THE CWA
SHOW WIDESPREAD CUMULUS DEVELOPMENT WITH 5 TO 7 KFT DEPTH. GIVEN
SHALLOW CLOUD DEPTH AND INSUFFICIENT MOISTURE ELSEWHERE IN THE
LAYER...ENTRAINMENT OF DRY AIR INTO THE CUMULUS FIELD SHOULD PREVENT
PRECIP DEVELOPMENT. IF ANY SHOWERS WERE TO FORM...THEY WOULD BE VERY
LIGHT AND LIKELY FOCUSED ON LAKE BREEZE CONVERGENCE ZONES ACROSS THE
INTERIOR CENTRAL AND EAST.
SATURDAY NIGHT THROUGH MONDAY NIGHT...WEAK SHORTWAVE RIDGING WILL BE
EXITING TO THE EAST SATURDAY EVENING AS A LARGE TROUGH AXIS ROTATES
SOUTHWARD ON THE BACKSIDE OF A DEEP EASTERN CANADIAN TROUGH. MODELS
HAVE BEEN PICKING UP ON A WEAK LEAD SHORTWAVE TROUGH TRACKING ACROSS
LAKE SUPERIOR SATURDAY NIGHT. DO NOT EXPECT MUCH MORE THAN SOME
INCREASED CLOUDINESS WITH THE WAVE. THE MAIN TROUGH AXIS THEN BEGINS
TO PUSH INTO THE AREA BY SUNDAY MORNING. THE 00Z NAM IS QUITE
AGGRESSIVE WITH BRINGING PRECIP INTO THE WESTERN CWA LATE SATURDAY
NIGHT AS IT APPEARS TO HAVE FALLEN VICTIM TO CONSIDERABLE
CONVECTIVE FEEDBACK FROM A POSSIBLE MCS ACROSS SOUTHERN MN. WILL
THEREFORE IGNORE THIS SOLUTION AND KEEP CONDITIONS DRY SATURDAY
NIGHT.
WITH MANY OF THE MODELS INDICATING DECENT MOISTURE TRANSPORT AND
ISENTROPIC LIFT CONFINED TO SOUTHERN MN AND CENTRAL/SOUTHERN WI...DO
NOT SEE THAT GREAT OF A POTENTIAL FOR ACTIVITY ACROSS THE CWA ON
SUNDAY. THE MAIN WILD CARD FOR THE DAY WILL BE HOW CLOUD DEBRIS FROM
ACTIVITY TO THE SOUTH LIMITS DAYTIME HEATING. WITH OVERALL MOISTURE
PROFILES ABOVE H7 QUITE DRY ACROSS UPPER MI...CLOUD COVER SHOULD
EASILY ERODE AND NOT INHIBIT OPTIMAL HEATING.
FOUND THE 00Z GFS QUITE REASONABLE WITH THE OVERALL SYNOPTIC
SET-UP...SO GAVE IT MORE WEIGHT IN THE FORECAST. A WEAK SECONDARY
SHORTWAVE WILL BE A FOCUS FOR AFTERNOON SHOWER AND STORM DEVELOPMENT
AS THE WAVE REACHES THE CENTRAL CWA BY MID AFTERNOON. WITH NORTHWEST
FLOW ALOFT...0 TO 6 KM BULK SHEAR WILL BE ON THE ORDER OF 35 KNOTS.
HOWEVER...SFC DEW POINTS ONLY IN THE MID 50S WILL LEAD TO POOR
INSTABILITY IN THE FORM OF MLCAPE OF 600 TO 900 J/KG. THIS SHOULD
LIMIT ANY ORGANIZED CONVECTION...AND OVERALL THUNDER COVERAGE FOR
THAT MATTER. HOWEVER...WITH A DRY SUBCLOUD LAYER AND DOWNDRAFT CAPE
OVER 1000 J/KG...THERE IS AN ELEVATED POTENTIAL FOR GUSTY WINDS
UNDER ANY STRONGER SHOWERS/STORMS. BEST CHANCE OF ANY CONVECTION
WILL BE SOUTH CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
EXPECT ANY ACTIVITY TO DIMINISH WITH THE LOSS OF DAYTIME HEATING
SUNDAY EVENING. FORCING IS QUITE CONVOLUTED AT THIS POINT...WITH THE
POTENTIAL FOR MULTIPLE WEAK SHORTWAVES TO TRACK ACROSS THE CWA
THROUGH MONDAY. HAVE OPTED TO KEEP A GENERAL SLIGHT CHANCE OF
SHOWERS IN THE FORECAST FOR SUNDAY NIGHT AND MONDAY GIVEN
UNCERTAINTY OF LOCATIONS FOR BEST FORCING. OVERALL THINKING IS THAT
THE PERIOD WILL BE MOSTLY DRY WITH ONLY SEE ISOLATED SHOWERS FROM
TIME TO TIME.
MONDAY NIGHT THROUGH THURSDAY...MODEL AGREEMENT IS GOOD WITH
BRINGING IN MID-LEVEL RIDGING FROM THE WEST BY MID-WEEK. THERE
IS...HOWEVER...SOME DISAGREEMENT AT HOW QUICK THE TROUGH AXIS
COMPLETELY CLEARS THE CWA. THE GFS HAS SPED UP THE TROUGH OVER
RECENT RUNS...THE ECMWF HAS SLOWED THE TROUGH...AND THE GEM HAS HAS
WEAKENED THE TROUGH. NOT MUCH ONE CAN DO WITH THIS INFORMATION OTHER
THAN STICK WITH CONSENSUS DATA. WITH LIMITED MID-LEVEL
MOISTURE...WILL KEEP PRECIP OUT OF THE FORECAST FOR MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE WILL THEN DOMINATE THE WEATHER THROUGH
THURSDAY. ANOTHER GOOD STRING OF NIGHTS WITH GOOD RADIATIONAL
COOLING APPEAR LIKELY...WITH TUESDAY NIGHT LEADING THE WAY AS THE
SFC HIGH SETTLES OVER THE WESTERN CWA. HAVE THUS LOWERED MIN TEMPS
SEVERAL DEGREES. THE GFS HINTS AT ISOLATED SHOWERS INTERIOR WEST ON
WEDNESDAY AFTERNOON...BUT A STOUT INVERSION WITH LIMITED RETURN
MOISTURE SHOULD PREVENT DEVELOPMENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 122 PM EDT FRI AUG 9 2013
VFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES THIS AFTERNOON.
THERE IS A SLIGHT CHANCE THAT SHOWERS COULD DEVELOP ON THE LAKE
BREEZE THIS AFTERNOON ACROSS EASTERN UPPER MICHIGAN...HOWEVER DO NOT
EXPECT THESE TO IMPACT KSAW. AS A LOW PRESSURE TROUGH CROSSES FROM
ONTARIO INTO QUEBEC THIS AFTERNOON AND EARLY EVENING...THE PRESSURE
GRADIENT BETWEEN THE LOW AND INCOMING HIGH PRESSURE WILL LEAD TO
GUSTY WINDS AT ALL THREE SITES...ESPECIALLY KCMX. EXPECT THESE WINDS
TO DIE DOWN AS THE LOW MOVES FURTHER EAST AND DAYTIME HEATING IS
LOST...SHORTLY AFTER 00Z.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25 RANGE TODAY
BEHIND A TROUGH MOVING THROUGH LAKE SUPERIOR. HOWEVER...THE STRONGER
WINDS WILL BE RELATIVELY BRIEF SO MAX WAVE HEIGHTS ARE EXPECTED TO
REMAIN MAINLY IN THE 3 TO 5 FOOT RANGE. WINDS WILL VEER NW LATE
TODAY AND DIMINISH TONIGHT TO 5 TO 15 KNOTS AS HIGH PRES BUILDS INTO
THE REGION.
THE COMBINATION OF HIGH PRESSURE TRACKING SOUTHEASTWARD THROUGH WI
AND LOW PRESSURE DROPPING SOUTHWARD FROM NORTHWEST ONTARIO SATURDAY
WILL BRING W TO NW WINDS OF 10 TO 20 KNOTS ACROSS MUCH OF THE LAKE.
THE TROUGH WILL SLOWLY CROSS THE LAKE SUNDAY AFTERNOON THROUGH
MONDAY WITH WINDS UNDER 15 KNOTS. HIGH PRESSURE WILL THEN DOMINATE
THE REGION THROUGH THE MIDDLE OF NEXT WEEK AND PRODUCE WINDS UNDER
15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...MCD
MARINE...JLB/KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
745 AM EDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED SEVERAL WEAK SHORTWAVES
ROTATING AROUND A MID/UPPER LEVEL LOW OVER NRN ONTARIO. SCT/ISOLD
-SHRA PERSISTED MAINLY ACROSS THE SRN CWA SUPPORTED BY A WEAK
850-700 MB TROUGH AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A
115 KNOT 300 MB JET TO THE NE OF LAKE SUPERIOR. A SHORTWAVE TROUGH
NW OF LAKE SUPERIOR ALSO SUPPORTED SOME ISOLD/SCT SHOWERS OVER NW
ONTARIO FROM SIOUX LOOKOUT TO DRYDEN.
TODAY...RADAR/SATELLITE TRENDS AND SHORT RANGE MODELS SUGGEST THAT
THE SHOWERS EARLY THIS MORNING WILL DEPART TO THE EAST OF THE CWA BY
AROUND 12Z. ALTHOUGH THE STRONGER 700-500 MB QVECTOR CONV ASSOCIATED
WITH THE NW ONTARIO SHRTWV WILL REMAIN NORTH OF UPPER MICHIGAN...THE
TAIL OF THIS FEATURE COMBINED WITH LOW LEVEL CONV ALONG THE LAKE
SUPERIOR BREEZE BOUNDARY AND MINIMAL MLCAPE VALUES TO NEAR 200 J/KG
IS EXPECTED TO GENERATE ISOLD -SHRA OVER INLAND PORTIONS OF
EAST CNTRL UPPER MICHIGAN. SOME -SHRA MAY ALSO BE POSSIBLE FARTHER
WEST FROM ESC-IMT ALONG A WEAK SFC TROUGH BUT CONFIDENCE WAS LOWER
SO PCPN WAS NOT MENTIONED AT THIS TIME. OTHERWISE...850 MB TEMPS
FROM 7C-9C WILL SUPPORT SCT/BKN CU DEVELOPMENT WITH CONTINUED BELOW
NORMAL HIGHS IN THE UPPER 60S AND LOWER 70S ARE EXPECTED.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND HIGH PRES BUILDING
INTO THE REGION...CLEARING SKIES AND DIMINISHING WINDS WILL LEAD TO
FAVORABLE RADIATIONAL COOLING CONDITIONS OVERNIGHT. SO...KEPT FCST
MINS CLOSER TO THE LOWER END OF GUIDANCE...WITH READINGS INTO THE
LOWER TO MID 40S INLAND AND IN THE LOWER 50S ALONG THE GREAT LAKES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EDT FRI AUG 9 2013
OTHER THAN A PERIOD OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS
SUNDAY AFTERNOON INTO MONDAY MORNING...A RATHER EXTENDED PERIOD OF
DRY WEATHER IS EXPECTED WITH SLIGHTLY BELOW NORMAL TEMPERATURES
THROUGH MUCH OF NEXT WEEK.
SATURDAY...DRY AIR WILL CONTINUE TO FILTER IN EARLY IN THE MORNING
AS A REINFORCING SFC HIGH AND WEAK RIDGING MOVE IN FROM THE WEST.
THERE HAS BEEN SOME HINT AT ISOLATED DIURNAL SHOWERS FORMING ACROSS
INTERIOR LOCATIONS BY BOTH THE NAM AND THE GFS OFF AND ON OVER THE
PAST TWO DAYS. INVESTIGATION OF FORECAST SOUNDINGS ACROSS THE CWA
SHOW WIDESPREAD CUMULUS DEVELOPMENT WITH 5 TO 7 KFT DEPTH. GIVEN
SHALLOW CLOUD DEPTH AND INSUFFICIENT MOISTURE ELSEWHERE IN THE
LAYER...ENTRAINMENT OF DRY AIR INTO THE CUMULUS FIELD SHOULD PREVENT
PRECIP DEVELOPMENT. IF ANY SHOWERS WERE TO FORM...THEY WOULD BE VERY
LIGHT AND LIKELY FOCUSED ON LAKE BREEZE CONVERGENCE ZONES ACROSS THE
INTERIOR CENTRAL AND EAST.
SATURDAY NIGHT THROUGH MONDAY NIGHT...WEAK SHORTWAVE RIDGING WILL BE
EXITING TO THE EAST SATURDAY EVENING AS A LARGE TROUGH AXIS ROTATES
SOUTHWARD ON THE BACKSIDE OF A DEEP EASTERN CANADIAN TROUGH. MODELS
HAVE BEEN PICKING UP ON A WEAK LEAD SHORTWAVE TROUGH TRACKING ACROSS
LAKE SUPERIOR SATURDAY NIGHT. DO NOT EXPECT MUCH MORE THAN SOME
INCREASED CLOUDINESS WITH THE WAVE. THE MAIN TROUGH AXIS THEN BEGINS
TO PUSH INTO THE AREA BY SUNDAY MORNING. THE 00Z NAM IS QUITE
AGGRESSIVE WITH BRINGING PRECIP INTO THE WESTERN CWA LATE SATURDAY
NIGHT AS IT APPEARS TO HAVE FALLEN VICTIM TO CONSIDERABLE
CONVECTIVE FEEDBACK FROM A POSSIBLE MCS ACROSS SOUTHERN MN. WILL
THEREFORE IGNORE THIS SOLUTION AND KEEP CONDITIONS DRY SATURDAY
NIGHT.
WITH MANY OF THE MODELS INDICATING DECENT MOISTURE TRANSPORT AND
ISENTROPIC LIFT CONFINED TO SOUTHERN MN AND CENTRAL/SOUTHERN WI...DO
NOT SEE THAT GREAT OF A POTENTIAL FOR ACTIVITY ACROSS THE CWA ON
SUNDAY. THE MAIN WILD CARD FOR THE DAY WILL BE HOW CLOUD DEBRIS FROM
ACTIVITY TO THE SOUTH LIMITS DAYTIME HEATING. WITH OVERALL MOISTURE
PROFILES ABOVE H7 QUITE DRY ACROSS UPPER MI...CLOUD COVER SHOULD
EASILY ERODE AND NOT INHIBIT OPTIMAL HEATING.
FOUND THE 00Z GFS QUITE REASONABLE WITH THE OVERALL SYNOPTIC
SET-UP...SO GAVE IT MORE WEIGHT IN THE FORECAST. A WEAK SECONDARY
SHORTWAVE WILL BE A FOCUS FOR AFTERNOON SHOWER AND STORM DEVELOPMENT
AS THE WAVE REACHES THE CENTRAL CWA BY MID AFTERNOON. WITH NORTHWEST
FLOW ALOFT...0 TO 6 KM BULK SHEAR WILL BE ON THE ORDER OF 35 KNOTS.
HOWEVER...SFC DEW POINTS ONLY IN THE MID 50S WILL LEAD TO POOR
INSTABILITY IN THE FORM OF MLCAPE OF 600 TO 900 J/KG. THIS SHOULD
LIMIT ANY ORGANIZED CONVECTION...AND OVERALL THUNDER COVERAGE FOR
THAT MATTER. HOWEVER...WITH A DRY SUBCLOUD LAYER AND DOWNDRAFT CAPE
OVER 1000 J/KG...THERE IS AN ELEVATED POTENTIAL FOR GUSTY WINDS
UNDER ANY STRONGER SHOWERS/STORMS. BEST CHANCE OF ANY CONVECTION
WILL BE SOUTH CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
EXPECT ANY ACTIVITY TO DIMINISH WITH THE LOSS OF DAYTIME HEATING
SUNDAY EVENING. FORCING IS QUITE CONVOLUTED AT THIS POINT...WITH THE
POTENTIAL FOR MULTIPLE WEAK SHORTWAVES TO TRACK ACROSS THE CWA
THROUGH MONDAY. HAVE OPTED TO KEEP A GENERAL SLIGHT CHANCE OF
SHOWERS IN THE FORECAST FOR SUNDAY NIGHT AND MONDAY GIVEN
UNCERTAINTY OF LOCATIONS FOR BEST FORCING. OVERALL THINKING IS THAT
THE PERIOD WILL BE MOSTLY DRY WITH ONLY SEE ISOLATED SHOWERS FROM
TIME TO TIME.
MONDAY NIGHT THROUGH THURSDAY...MODEL AGREEMENT IS GOOD WITH
BRINGING IN MID-LEVEL RIDGING FROM THE WEST BY MID-WEEK. THERE
IS...HOWEVER...SOME DISAGREEMENT AT HOW QUICK THE TROUGH AXIS
COMPLETELY CLEARS THE CWA. THE GFS HAS SPED UP THE TROUGH OVER
RECENT RUNS...THE ECMWF HAS SLOWED THE TROUGH...AND THE GEM HAS HAS
WEAKENED THE TROUGH. NOT MUCH ONE CAN DO WITH THIS INFORMATION OTHER
THAN STICK WITH CONSENSUS DATA. WITH LIMITED MID-LEVEL
MOISTURE...WILL KEEP PRECIP OUT OF THE FORECAST FOR MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE WILL THEN DOMINATE THE WEATHER THROUGH
THURSDAY. ANOTHER GOOD STRING OF NIGHTS WITH GOOD RADIATIONAL
COOLING APPEAR LIKELY...WITH TUESDAY NIGHT LEADING THE WAY AS THE
SFC HIGH SETTLES OVER THE WESTERN CWA. HAVE THUS LOWERED MIN TEMPS
SEVERAL DEGREES. THE GFS HINTS AT ISOLATED SHOWERS INTERIOR WEST ON
WEDNESDAY AFTERNOON...BUT A STOUT INVERSION WITH LIMITED RETURN
MOISTURE SHOULD PREVENT DEVELOPMENT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 745 AM EDT FRI AUG 9 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD.
ANOTHER TROUGH IS EXPECTED TO MOVE THROUGH UPPER MICHIGAN TODAY THAT
COULD SET OFF SOME PCPN...MAINLY FOR SAW. HOWEVER...WITH DRY AIR
OVER THE REGION...SHRA CHANCES/COVERAGE/INTENSITY WILL BE LOW AND WAS NOT
INCLUDED IN THE TAF. OTHERWISE...WEST WINDS WILL INCREASE AND BECOME
GUSTY BY MIDDAY...ESPECIALLY OVER THE EXPOSED HIGHER TERRAIN AT CMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25 RANGE TODAY
BEHIND A TROUGH MOVING THROUGH LAKE SUPERIOR. HOWEVER...THE STRONGER
WINDS WILL BE RELATIVELY BRIEF SO MAX WAVE HEIGHTS ARE EXPECTED TO
REMAIN MAINLY IN THE 3 TO 5 FOOT RANGE. WINDS WILL VEER NW LATE
TODAY AND DIMINISH TONIGHT TO 5 TO 15 KNOTS AS HIGH PRES BUILDS INTO
THE REGION.
THE COMBINATION OF HIGH PRESSURE TRACKING SOUTHEASTWARD THROUGH WI
AND LOW PRESSURE DROPPING SOUTHWARD FROM NORTHWEST ONTARIO SATURDAY
WILL BRING W TO NW WINDS OF 10 TO 20 KNOTS ACROSS MUCH OF THE LAKE.
THE TROUGH WILL SLOWLY CROSS THE LAKE SUNDAY AFTERNOON THROUGH
MONDAY WITH WINDS UNDER 15 KNOTS. HIGH PRESSURE WILL THEN DOMINATE
THE REGION THROUGH THE MIDDLE OF NEXT WEEK AND PRODUCE WINDS UNDER
15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB/KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
459 AM EDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED SEVERAL WEAK SHORTWAVES
ROTATING AROUND A MID/UPPER LEVEL LOW OVER NRN ONTARIO. SCT/ISOLD
-SHRA PERSISTED MAINLY ACROSS THE SRN CWA SUPPORTED BY A WEAK
850-700 MB TROUGH AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A
115 KNOT 300 MB JET TO THE NE OF LAKE SUPERIOR. A SHORTWAVE TROUGH
NW OF LAKE SUPERIOR ALSO SUPPORTED SOME ISOLD/SCT SHOWERS OVER NW
ONTARIO FROM SIOUX LOOKOUT TO DRYDEN.
TODAY...RADAR/SATELLITE TRENDS AND SHORT RANGE MODELS SUGGEST THAT
THE SHOWERS EARLY THIS MORNING WILL DEPART TO THE EAST OF THE CWA BY
AROUND 12Z. ALTHOUGH THE STRONGER 700-500 MB QVECTOR CONV ASSOCIATED
WITH THE NW ONTARIO SHRTWV WILL REMAIN NORTH OF UPPER MICHIGAN...THE
TAIL OF THIS FEATURE COMBINED WITH LOW LEVEL CONV ALONG THE LAKE
SUPERIOR BREEZE BOUNDARY AND MINIMAL MLCAPE VALUES TO NEAR 200 J/KG
IS EXPECTED TO GENERATE ISOLD -SHRA OVER INLAND PORTIONS OF
EAST CNTRL UPPER MICHIGAN. SOME -SHRA MAY ALSO BE POSSIBLE FARTHER
WEST FROM ESC-IMT ALONG A WEAK SFC TROUGH BUT CONFIDENCE WAS LOWER
SO PCPN WAS NOT MENTIONED AT THIS TIME. OTHERWISE...850 MB TEMPS
FROM 7C-9C WILL SUPPORT SCT/BKN CU DEVELOPMENT WITH CONTINUED BELOW
NORMAL HIGHS IN THE UPPER 60S AND LOWER 70S ARE EXPECTED.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND HIGH PRES BUILDING
INTO THE REGION...CLEARING SKIES AND DIMINISHING WINDS WILL LEAD TO
FAVORABLE RADIATIONAL COOLING CONDITIONS OVERNIGHT. SO...KEPT FCST
MINS CLOSER TO THE LOWER END OF GUIDANCE...WITH READINGS INTO THE
LOWER TO MID 40S INLAND AND IN THE LOWER 50S ALONG THE GREAT LAKES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EDT FRI AUG 9 2013
OTHER THAN A PERIOD OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS
SUNDAY AFTERNOON INTO MONDAY MORNING...A RATHER EXTENDED PERIOD OF
DRY WEATHER IS EXPECTED WITH SLIGHTLY BELOW NORMAL TEMPERATURES
THROUGH MUCH OF NEXT WEEK.
SATURDAY...DRY AIR WILL CONTINUE TO FILTER IN EARLY IN THE MORNING
AS A REINFORCING SFC HIGH AND WEAK RIDGING MOVE IN FROM THE WEST.
THERE HAS BEEN SOME HINT AT ISOLATED DIURNAL SHOWERS FORMING ACROSS
INTERIOR LOCATIONS BY BOTH THE NAM AND THE GFS OFF AND ON OVER THE
PAST TWO DAYS. INVESTIGATION OF FORECAST SOUNDINGS ACROSS THE CWA
SHOW WIDESPREAD CUMULUS DEVELOPMENT WITH 5 TO 7 KFT DEPTH. GIVEN
SHALLOW CLOUD DEPTH AND INSUFFICIENT MOISTURE ELSEWHERE IN THE
LAYER...ENTRAINMENT OF DRY AIR INTO THE CUMULUS FIELD SHOULD PREVENT
PRECIP DEVELOPMENT. IF ANY SHOWERS WERE TO FORM...THEY WOULD BE VERY
LIGHT AND LIKELY FOCUSED ON LAKE BREEZE CONVERGENCE ZONES ACROSS THE
INTERIOR CENTRAL AND EAST.
SATURDAY NIGHT THROUGH MONDAY NIGHT...WEAK SHORTWAVE RIDGING WILL BE
EXITING TO THE EAST SATURDAY EVENING AS A LARGE TROUGH AXIS ROTATES
SOUTHWARD ON THE BACKSIDE OF A DEEP EASTERN CANADIAN TROUGH. MODELS
HAVE BEEN PICKING UP ON A WEAK LEAD SHORTWAVE TROUGH TRACKING ACROSS
LAKE SUPERIOR SATURDAY NIGHT. DO NOT EXPECT MUCH MORE THAN SOME
INCREASED CLOUDINESS WITH THE WAVE. THE MAIN TROUGH AXIS THEN BEGINS
TO PUSH INTO THE AREA BY SUNDAY MORNING. THE 00Z NAM IS QUITE
AGGRESSIVE WITH BRINGING PRECIP INTO THE WESTERN CWA LATE SATURDAY
NIGHT AS IT APPEARS TO HAVE FALLEN VICTIM TO CONSIDERABLE
CONVECTIVE FEEDBACK FROM A POSSIBLE MCS ACROSS SOUTHERN MN. WILL
THEREFORE IGNORE THIS SOLUTION AND KEEP CONDITIONS DRY SATURDAY
NIGHT.
WITH MANY OF THE MODELS INDICATING DECENT MOISTURE TRANSPORT AND
ISENTROPIC LIFT CONFINED TO SOUTHERN MN AND CENTRAL/SOUTHERN WI...DO
NOT SEE THAT GREAT OF A POTENTIAL FOR ACTIVITY ACROSS THE CWA ON
SUNDAY. THE MAIN WILD CARD FOR THE DAY WILL BE HOW CLOUD DEBRIS FROM
ACTIVITY TO THE SOUTH LIMITS DAYTIME HEATING. WITH OVERALL MOISTURE
PROFILES ABOVE H7 QUITE DRY ACROSS UPPER MI...CLOUD COVER SHOULD
EASILY ERODE AND NOT INHIBIT OPTIMAL HEATING.
FOUND THE 00Z GFS QUITE REASONABLE WITH THE OVERALL SYNOPTIC
SET-UP...SO GAVE IT MORE WEIGHT IN THE FORECAST. A WEAK SECONDARY
SHORTWAVE WILL BE A FOCUS FOR AFTERNOON SHOWER AND STORM DEVELOPMENT
AS THE WAVE REACHES THE CENTRAL CWA BY MID AFTERNOON. WITH NORTHWEST
FLOW ALOFT...0 TO 6 KM BULK SHEAR WILL BE ON THE ORDER OF 35 KNOTS.
HOWEVER...SFC DEW POINTS ONLY IN THE MID 50S WILL LEAD TO POOR
INSTABILITY IN THE FORM OF MLCAPE OF 600 TO 900 J/KG. THIS SHOULD
LIMIT ANY ORGANIZED CONVECTION...AND OVERALL THUNDER COVERAGE FOR
THAT MATTER. HOWEVER...WITH A DRY SUBCLOUD LAYER AND DOWNDRAFT CAPE
OVER 1000 J/KG...THERE IS AN ELEVATED POTENTIAL FOR GUSTY WINDS
UNDER ANY STRONGER SHOWERS/STORMS. BEST CHANCE OF ANY CONVECTION
WILL BE SOUTH CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
EXPECT ANY ACTIVITY TO DIMINISH WITH THE LOSS OF DAYTIME HEATING
SUNDAY EVENING. FORCING IS QUITE CONVOLUTED AT THIS POINT...WITH THE
POTENTIAL FOR MULTIPLE WEAK SHORTWAVES TO TRACK ACROSS THE CWA
THROUGH MONDAY. HAVE OPTED TO KEEP A GENERAL SLIGHT CHANCE OF
SHOWERS IN THE FORECAST FOR SUNDAY NIGHT AND MONDAY GIVEN
UNCERTAINTY OF LOCATIONS FOR BEST FORCING. OVERALL THINKING IS THAT
THE PERIOD WILL BE MOSTLY DRY WITH ONLY SEE ISOLATED SHOWERS FROM
TIME TO TIME.
MONDAY NIGHT THROUGH THURSDAY...MODEL AGREEMENT IS GOOD WITH
BRINGING IN MID-LEVEL RIDGING FROM THE WEST BY MID-WEEK. THERE
IS...HOWEVER...SOME DISAGREEMENT AT HOW QUICK THE TROUGH AXIS
COMPLETELY CLEARS THE CWA. THE GFS HAS SPED UP THE TROUGH OVER
RECENT RUNS...THE ECMWF HAS SLOWED THE TROUGH...AND THE GEM HAS HAS
WEAKENED THE TROUGH. NOT MUCH ONE CAN DO WITH THIS INFORMATION OTHER
THAN STICK WITH CONSENSUS DATA. WITH LIMITED MID-LEVEL
MOISTURE...WILL KEEP PRECIP OUT OF THE FORECAST FOR MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE WILL THEN DOMINATE THE WEATHER THROUGH
THURSDAY. ANOTHER GOOD STRING OF NIGHTS WITH GOOD RADIATIONAL
COOLING APPEAR LIKELY...WITH TUESDAY NIGHT LEADING THE WAY AS THE
SFC HIGH SETTLES OVER THE WESTERN CWA. HAVE THUS LOWERED MIN TEMPS
SEVERAL DEGREES. THE GFS HINTS AT ISOLATED SHOWERS INTERIOR WEST ON
WEDNESDAY AFTERNOON...BUT A STOUT INVERSION WITH LIMITED RETURN
MOISTURE SHOULD PREVENT DEVELOPMENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 133 AM EDT FRI AUG 9 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. ON
FRI...ANOTHER TROUGH WILL MAKE ITS WAY INTO THE U.P. EXCEPT THE
AIRMASS IS MUCH DRIER THAN TODAY. EXPECTING THAT KCMX HAS THE ONLY
CHANCE OF SEEING THESE SHOWERS...AND WAS NOT CONFIDENT ENOUGH TO
PLACE IN THE TAF. WILL GET GUSTY WINDS AT ALL SITES AS WELL FRI
AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25 RANGE TODAY
BEHIND A TROUGH MOVING THROUGH LAKE SUPERIOR. HOWEVER...THE STRONGER
WINDS WILL BE RELATIVELY BRIEF SO MAX WAVE HEIGHTS ARE EXPECTED TO
REMAIN MAINLY IN THE 3 TO 5 FOOT RANGE. WINDS WILL VEER NW LATE
TODAY AND DIMINISH TONIGHT TO 5 TO 15 KNOTS AS HIGH PRES BUILDS INTO
THE REGION.
THE COMBINATION OF HIGH PRESSURE TRACKING SOUTHEASTWARD THROUGH WI
AND LOW PRESSURE DROPPING SOUTHWARD FROM NORTHWEST ONTARIO SATURDAY
WILL BRING W TO NW WINDS OF 10 TO 20 KNOTS ACROSS MUCH OF THE LAKE.
THE TROUGH WILL SLOWLY CROSS THE LAKE SUNDAY AFTERNOON THROUGH
MONDAY WITH WINDS UNDER 15 KNOTS. HIGH PRESSURE WILL THEN DOMINATE
THE REGION THROUGH THE MIDDLE OF NEXT WEEK AND PRODUCE WINDS UNDER
15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...07
MARINE...JLB/KLUBER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
426 AM CDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT FRI AUG 9 2013
A SURFACE RIDGE ORIENTED ALONG THE UPPER MINNESOTA RIVER VALLEY WAS
BUILDING ACROSS THE REGION...WITH MOSTLY CLEAR SKIES AND LIGHT WINDS
ACROSS THE REGION. AS OF THIS MORNING A FEW AREAS OF FOG HAD
DEVELOPED...BUT THESE WERE ISOLATED INSTANCES CONFINED MAINLY TO THE
LOW LYING AREAS. A LINGERING AREA OF SHOWERS STRADDLED THE MN/IA
BORDER LIKELY A RESULT OF WEAK H850 FGEN COUPLED WITH FAVORABLE JET
DYNAMICS IN THE RIGHT ENTRANCE REGION OF A H300 SPEED MAX. AT UPPER
LEVELS THE TWO MAIN FEATURES OF INTEREST WERE THE PERSISTENT CUTOFF
LOW ACROSS ONTARIO...AS WELL AS ANOTHER PV ANOMALY CENTERED OVER THE
REDWOOD FORESTS OF NORTHERN CALIFORNIA.
EVENTUALLY A SHORTWAVE WILL EJECT OFF THE CALIFORNIAN LOW AND BRING
A CHANCE FOR SHOWERS AND THUNDERSTORMS THIS WEEKEND. IN THE MEAN
TIME...NORTHWEST FLOW AND SURFACE RIDGING WILL KEEP THE REGION DRY
TODAY AND TONIGHT. COLD AIR ADVECTION TOGETHER WITH DIABATIC SURFACE
HEATING WILL QUICKLY MIX THE BOUNDARY LAYER TODAY ALLOWING NORTHWEST
WINDS OF 15 TO 20 MPH TO BECOME WIDESPREAD BY THIS AFTERNOON. ASIDE
FROM THESE BREEZY CONDITIONS...NO SIGNIFICANT SENSIBLE WEATHER TO
SPEAK OF WITH TEMPERATURES CONTINUING ON THE COOL SIDE AS AFTERNOON
HIGHS ONLY MANAGE MID TO UPPER 70S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 326 AM CDT FRI AUG 9 2013
NOT MUCH CHANGE IN THE EXTENDED FROM WHAT WE HAVE BEEN SEEING THE
PAST COUPLE DAYS. ITS FAIRLY OBVIOUS WHEN LOOKING AT THE 240-HR RUN
TOTAL QPF OFF THE GFS/ECMWF THAT THE SYNOPTIC FRONTAL BOUNDARY
STRETCHES EASTWARD FROM OK/KS TO THE MID ATLANTIC STATES WITH AN
ANOMALOUSLY DEEP TROUGH IN THE EAST. THIS IS WHERE THE MOST RAIN
IS EXPECTED TO FALL OVER THE NEXT 7-10 DAYS. THE STRONG RIDGING
OVER THE ATLANTIC OCEAN IS FORCING THE PERSISTENT TROUGHING IN THE
EASTERN CONUS AND RIDGING UPSTREAM IN THE WEST. MN/WI REMAINS
UNDER THE INFLUENCE OF COOLER CYCLONIC FLOW AND WE EXPECT THIS TO
CONTINUE FOR AT LEAST THE NEXT SEVERAL DAYS. THE NEXT CHANCE FOR
SHOWERS AND STORMS COMES ON SUNDAY WHEN A WAVE EMBEDDED IN
NORTHWEST FLOW PASSES ACROSS THE AREA. AS IS TYPICAL...THE MODEL
GUIDANCE IS STARTING TO BECOME MORE ALIKE IN THERE REPRESENTATION
AND TIMING OF THIS FEATURE. DP/DT OF THE NAM/GFS/ECMWF ALSO SHOWS
LESS AMPLIFICATION WITH TIME AND THEREFORE FASTER SOLUTIONS. EVEN
WITH THE SHALLOWER AND FASTER SOLUTIONS...WE HAVE NOT REALLY SEEN
A SIGNIFICANT DROP IN THE MODEL QPF. THE 09.00/06Z RUNS ARE STILL
GENERATING BETWEEN 0.50-1.50" OF CONVECTIVE PRECIP. THE SPECIFIC
PLACEMENT OF THE BULLS EYE IS STILL NOT CERTAIN...BUT THERE HAS
BEEN A GRADUAL SHIFT SOUTH. THIS MAKES SENSE BECAUSE IT`S WHERE
THE GREATEAST POOL OF CAPE IS LOCATED /IN THE STATES JUST TO OUR
SOUTH/. LOW CONFIDENCE IN THE QPF/POP FORECAST SUNDAY...LOOKS
BETTER IN SOUTHERN MN...BUT BIG QUESTION MARKS STILL FOR PLACES
LIKE ST. CLOUD...TWIN CITIES...AND EAU CLAIRE.
THE GFS/ECMWF/GEFS ARE IN GOOD AGREEMENT WITH THE POSITION OF THE
MASS FIELDS THROUGH 100-120 HOURS. HOWEVER...BY NEXT
WEDNESDAY...THE OPERATIONAL GFS BECOMES A LITTLE MORE PROGRESSIVE
IN MOVING THE WEST COAST RIDING CLOSER TO MN/WI. THIS WOULD
SUGGEST WARMER TEMPS FOR THE SECOND HALF OF NEXT WEEK /MORE LOWER
80S AT LEAST/. THE ECMWF HANGS THE RIDGE BACK AND THE GEFS IS ALSO
A BIT FARTHER WEST THAN ITS OPERATIONAL COUNTERPART. HIGH
CONFIDENCE IN THE TEMP FORECAST OVER THE NEXT 7 DAYS. THERE IS VERY
LITTLE SPREAD IN THE GUIDANCE AND MOST DAYS THE RANGE IN HIGH
TEMPS IS 3-5 DEGREES /A BIT MORE FOR LOW TEMPS/. THE BIGGEST TEMP
SPREAD COMES ON SUNDAY WITH THE WARM ADVECTION...THEN CLOUD COVER
AND RAIN...SO NO SURPRISE THERE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1241 AM CDT FRI AUG 9 2013
SKIES WILL CLEAR OVERNIGHT WHICH WILL SET THE STAGE FOR FOG AT A
FEW SUSCEPTIBLE LOCATIONS...MAINLY KRWF...KSTC...AND KEAU. HIRES
MODELS SUCH AS THE HRRR AND HOPWRF CONTINUE TO DROP VISIBILITIES
LESS THAN A HALF MILE...SUPPORTING THE INCLUSION OF FOG AT THOSE
SITES. ON FRIDAY NORTHWEST WINDS WILL INCREASE AND COULD GUST TO
NEAR 20KTS DURING THE AFTERNOON.
KMSP...
LIGHT WINDS SHOULD GO CALM OVERNIGHT. THE FOG POTENTIAL AT MSP IS
TOO LOW TO INCLUDE MENTION IN THE TAFS. ON FRIDAY EXPECT VFR
CONDITIONS WITH NORTHWEST WINDS GUSTING TO NEAR 20KTS AT TIMES.
THE GUSTS WILL TAPER OFF AFTER SUNSET.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NW AT 05KTS.
SUN...VFR WITH -TSRA POSSIBLE. WINDS S AT 05KTS.
MON...VFR. WINDS N AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...CLF
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1249 AM CDT FRI AUG 9 2013
.UPDATED FOR 06Z AVIATION DISCUSSION...
ISSUED AT 1241 AM CDT FRI AUG 9 2013
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1225 PM CDT THU AUG 8 2013
SHOWER ACTIVITY WILL CONTINUE TO WANE INTO THE EVENING HOURS AS
THE WEAK IMPULSE SLIDES EAST OF THE AREA. MID LEVEL CLOUDS SCATTER
OUT THIS EVENING...WITH TEMPERATURES COOLING INTO THE UPPER 40S TO
UPPER 50S RANGE. DRY CONDITIONS ARE EXPECTED FOR FRIDAY AS SURFACE
HIGH PRESSURE ARRIVES AND DRYING OF THE MID LEVELS YIELDS MOSTLY
SUNNY SKIES. 75 TO 80 DEGREE HIGHS WITH A FEW SITES ALONG THE MN
RIVER VALLEY POTENTIALLY REACHING INTO THE LOW 80S STILL LOOKS
REASONABLE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 232 PM CDT THU AUG 8 2013
THE MAIN CHG FOR THE EXTENDED PERIOD IS WHETHER SAT/SUNDAY/S WX
SYSTEM WILL TRACK FASTER...HOLD BACK...OR/AND BE A BIT FURTHER TO
THE SOUTH.
THE SHRTWV IN QUESTION IS VERY WEAK AND DISORGANIZED ACROSS THE
SOUTHWESTERN U.S. EARLY THIS AFTN. THE STRONG UPPER LOW ACROSS
SOUTHERN CANADA WILL SLOWLY MODIFY AND MOVE OFF TO THE EAST/NE
OVER THE NEXT TWO DAYS. THE MEAN FLOW ACROSS THE UPPER MIDWEST
WILL BE CAUGHT IN BETWEEN THIS DEPARTING UPPER LOW...AND THE
SHRTWV MOVING NORTH...THEN EVENTUALLY E-SE ACROSS THE NORTHERN
PLAINS/UPPER MIDWEST OVER THE WEEKEND. SEVERAL MODEL RUNS AGO THIS
SYSTEM WAS STRONGER AND SLOWLY ACROSS THE DAKOTAS...AND NOT
AFFECTING MN/WI UNTIL SUNDAY/SUNDAY NIGHT. THEREFORE...THIS
WEEKENDS FORECAST IS HIGHLY BASED ON THE MOVEMENT OF THIS SHRTWV
AND THE STRENGTH OF IT ONCE IT MOVES ACROSS THE UPPER MIDWEST.
ALTHOUGH THE SFC LOW AND ASSOCIATED SFC BOUNDARY ARE FURTHER TO
THE SOUTH ACROSS THE UPPER MIDWEST/NORTHERN PLAINS AS IN THE
PREVIOUS MODEL RUN/S...THIS FEATURE WILL LIKELY GO THROUGH A PERIOD
OF CHGS ON STRENGTH AND POSITION. DUE TO MOST OF THE RICH TROPICAL
MOISTURE HOLDING ACROSS THE CENTRAL PLAINS/MID MISSISSIPPI VALLEY
REGION...OUR SYSTEM WILL LIKELY NOT BE A WET IN TERMS OF RAINFALL
AMTS.
NOT TOO MANY CHGS PAST SUNDAY WITH THE CONTINUED W-NW FLOW ALOFT
AS THE MEAN TROUGH HOLDS ACROSS EASTERN NORTH AMERICA...WITH A
WEAK RIDGE ACROSS THE ROCKIES. AS WITH YESTERDAY/S DISCUSSION ON
THE RETROGRADING OF THE UPPER RIDGE ACROSS THE SOUTHERN
PLAINS...AND INTO THE DESERT SW...THIS STILL REMAINS PLAUSIBLE
BASED ON THE LATEST UPPER AIR FLOW IN THE NEXT 7 TO 10 DAYS. OUR
WEATHER WILL REMAIN SOMEWHAT COOLER THAN NORMAL...WITH HUMIDITY
LEVELS QUITE DRY FOR MID AUGUST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1241 AM CDT FRI AUG 9 2013
SKIES WILL CLEAR OVERNIGHT WHICH WILL SET THE STAGE FOR FOG AT A
FEW SUSCEPTIBLE LOCATIONS...MAINLY KRWF...KSTC...AND KEAU. HIRES
MODELS SUCH AS THE HRRR AND HOPWRF CONTINUE TO DROP VISIBILITIES
LESS THAN A HALF MILE...SUPPORTING THE INCLUSION OF FOG AT THOSE
SITES. ON FRIDAY NORTHWEST WINDS WILL INCREASE AND COULD GUST TO
NEAR 20KTS DURING THE AFTERNOON.
KMSP...
LIGHT WINDS SHOULD GO CALM OVERNIGHT. THE FOG POTENTIAL AT MSP IS
TOO LOW TO INCLUDE MENTION IN THE TAFS. ON FRIDAY EXPECT VFR
CONDITIONS WITH NORTHWEST WINDS GUSTING TO NEAR 20KTS AT TIMES.
THE GUSTS WILL TAPER OFF AFTER SUNSET.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NW AT 05KTS.
SUN...VFR WITH -TSRA POSSIBLE. WINDS S AT 05KTS.
MON...VFR. WINDS N AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...JLT
AVIATION...JRB
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
955 AM CDT FRI AUG 9 2013
.UPDATE...LATEST SATELLITE IMAGERY SHOWED THAT THE MEAN UPPER RIDGE
WAS STARTING TO SHOW SIGNS OF SOME SLIGHT WEAKENING. THIS WAS NOTED
BY THE 850-700 MB INVERTED TROUGH OVER THE SOUTH HALF. AREA RADARS
WERE STARTING TO PICK UP SOME CONVECTION ACROSS THE COAST. WITH
CURRENT RADAR TRENDS HAVE PUSHED BACK GENERAL RAIN COVERAGE TIME IN
THE GRIDS. PWATS DOWN AT KLIX WAS AROUND 2.3 INCHES...WHILE 2
INCHES AT KJAN. PWATS WERE INCREASING FROM THE SOUTH AS DEEPER
TROPICAL MOISTURE WAS ADVANCING NORTH ACROSS THE REGION. EVEN THOUGH
JAN SOUNDING SHOWS SOME GOOD DCAPE THE ADVANCING DEEPER TROPICAL
MOISTURE WILL REDUCE DCAPES SOME FOR THIS AFTERNOON. HOWEVER A
FEW STRONG STORMS WITH SOME GUSTY WINDS AND LOCALLY HEAVY DOWNPOURS
IS NOT OUT OF THE QUESTION. LATEST HRRR SHOWS SOME DECENT COVERAGE AS
MOISTURE CONVERGENCE AND MOISTURE TRANSPORT OF TROPICAL MOISTURE
INCREASES SOME TODAY AROUND THE INVERTED TROUGH. SO WILL KEEP
CURRENT SCATTERED POPS FOR THIS AFTERNOON. CURRENT HOURLY TEMPS
LOOKED TO BE ON TRACK FOR THIS MORNING. AS FAR AS HEAT ADVISORY IS
CONCERN SOME AREAS MAY STRUGGLE TO REACH CRITERIA IN THE EASTERN
PORTION...BUT WILL CONTINUE TO KEEP THE ADVISORY IN PLACE FOR THE
WEST HALF. WILL KEEP THE CURRENT HIGHS FROM THE LOWER 90S EAST TO
THE UPPER 90S IN SOUTHEAST ARKANSAS./17/
./PREVIOUS DISCUSSION...426 AM CDT FRI AUG 9 2013
.DISCUSSION...
TODAY THROUGH SATURDAY NIGHT...
A FEW STORMS THAT DEVELOPED A FEW HOURS AGO OVER NORTH CENTRAL MS
ALONG AN OUTFLOW BOUNDARY HAVE DISSIPATED. OVERALL...THE PATTERN
REMAINS THE SAME WITH A VERY HOT AND HUMID AIRMASS ANCHORED OVER THE
ARKLAMISS REGION. THE HEAT ADVISORY WILL CONTINUE FOR ABOUT THE
WESTERN HALF OF THE FORECAST AREA...BUT CONVECTIVE COVERAGE MAY
EXTEND A LITTLE FARTHER WEST THAN IN RECENT DAYS.
THE HEAT ADVISORY IS A LITTLE MORE PROBLEMATIC TODAY AS EXPLICIT
FORECASTED HEAT INDICES ARE A BIT LOWER THAN HEAT ADVISORY THRESHOLD.
WITH TEMPERATURES STRUGGLING TO FALL BELOW 80 DEG F THIS MORNING
AFTER SEVERAL DAYS OF HIGH HEAT STRESS...WOULD RATHER NOT CANCEL THE
ADVISORY JUST YET. AS HAS BEEN THE CASE...LOCATIONS IN EASTERN MS
SHOULD EXPERIENCE A SHORTER DURATION OF 105+ HEAT INDICES BEFORE
AFTERNOON CONVECTION BRINGS SOME RELIEF. GUIDANCE IS ACTUALLY A
LITTLE HOTTER FOR SATURDAY THAN TODAY IN MANY LOCATIONS. HAVE
EXTENDED THE HEAT ADVISORY FOR PORTIONS OF THE DELTA REGION WHERE
CONFIDENCE IS GREATEST...BUT THE ADVISORY MAY NEED TO BE EXPANDED IF
THE FORECAST FOR GREATER HEAT CONTINUES.
AS FOR THUNDERSTORM POTENTIAL...MODELS INDICATE THAT THE HIGHLY
DIURNAL ISOLATED-SCATTERED THUNDERSTORM PATTERN WILL CONTINUE FOR
TODAY AND SATURDAY WITH THE BEST THERMODYNAMIC ENVIRONMENT AND DEEP
LAYER MOISTURE AND CONVERGENCE SHIFTING FARTHER NORTHWEST WITH TIME
AS MOISTURE TRANSPORT FROM THE GULF INCREASES. MID LEVEL LAPSE RATES
HAVE STEEPENED A BIT...AND COMBINED WITH THE VERY HOT SURFACE
TEMPERATURES/STEEP LOW LEVEL LAPSE RATES...THEY COULD INCREASE THE
RISK FOR STRONG MICROBURSTS DURING PEAK HEATING. IN ADDITION...SUBTLE
WEAKENING/SUPPRESSION OF THE RIDGE WILL ALLOW PERTURBATIONS IN THE
WESTERLIES TO INFRINGE UPON NORTHERN PORTIONS OF THE ARKLAMISS AND
HAVE INCREASED POPS THERE JUST A LITTLE. /EC/
SUNDAY THROUGH FRIDAY...
THE PATTERN FOR THE FIRST PART OF NEXT WEEK FEATURES AN EAST-WEST
DRAPED SURFACE FRONT JUST TO OUR NORTH...WITH A "FLAT" SUBTROPICAL
RIDGE AXIS OVER THE ARKLAMISS THAT EXTENDS OVER THE SOUTHERN PLAINS.
SURFACE HIGH PRESSURE WILL BE CENTERED OFF TO OUR EAST KEEPING
WARM/HUMID SOUTHERLY FLOW OFF THE GULF IN PLACE...AND IT LOOKS LIKE
AN ENHANCED SEA BREEZE COULD BRING SOME DECENT RAIN CHANCES TO
SOUTHERN ZONES SUNDAY AFTERNOON WITH JUST ISOLATED TO SCATTERED
DIURNAL CONVECTION FURTHER NORTH. FROM THERE IT APPEARS RAIN CHANCES
WILL BE ON THE INCREASE HEADED INTO THE FIRST PART OF THE WORK WEEK
AS THE UPPER RIDGE SHIFTS WEST AND HEIGHTS FALL ACROSS THE DEEP
SOUTH. WHILE MOST OF THIS ACTIVITY SHOULD BE CONFINED TO THE
AFTERNOON AND EARLY EVENING HOURS THE POSSIBILITY FOR SOME ACTIVITY
PERSISTING OVERNIGHT WILL BE A BIT HIGHER GIVEN PASSING UPPER
DISTURBANCES IN THIS PATTERN. THE INCREASED RAIN CHANCES AND FALLING
HEIGHTS WILL ALSO ALLOW TEMPERATURES TO RETURN CLOSER TO NORMAL FOR
MID AUGUST/GENERALLY LOWER 90S. CONVECTIVE PARAMETERS LOOK TO
SUPPORT A FEW STRONG STORMS DURING THIS PERIOD...BUT NOTHING OUT OF
ORDINARY FOR THIS TIME OF YEAR AND WILL OMIT MENTION OF ANY
SPECIFICS IN THE HWO.
THE MODELS CONTINUE TO SHOW THE AFOREMENTIONED SURFACE FRONT DROPPING
SOUTH INTO THE ARKLAMISS BY WEDNESDAY...PROVIDING FOCUS FOR AREAWIDE
SHOWERS AND THUNDERSTORMS AS THIS OCCURS. ALTHOUGH SPECIFICS ARE
STILL UP IN THE AIR IT DOES LOOK LIKE THE FRONT WILL DRIFT ALL THE
WAY ACROSS THE ARKLAMISS BY LATE THU OR SOMETIME FRI ALLOWING DRIER
AIR TO FILTER IN...A WELCOME CHANGE CONSIDERING THE STRETCH OF HOT AND
HUMID WEATHER WE`VE BEEN THROUGH RECENTLY. OVERNIGHT LOWS FALLING
INTO THE MID TO UPPER 60S WILL BE MUCH ANTICIPATED LATE IN THE WEEK
AND HOPEFULLY OVER THE WEEKEND AS A RESULT.
OTHER THAN A FEW MINOR ADJUSTMENTS THE GFS MOS POPS/TEMPS LOOKED
REASONABLE THROUGH THE EXTENDED RANGE. /BK/
&&
.AVIATION...THE BRIEF PERIOD OF MVFR CATEGORY FOG AND PATCHY AREAS
OF IFR/MVFR CIGS THAT DEVELOPED THIS MORNING HAS BURNED OFF AND VFR
CONDITIONS WL PREVAIL THROUGH 17Z. AFTN TSTM COVERAGE MAY BE A
LITTLE GREATER TODAY...POSSIBLY AFFECTING SITES FARTHER WEST
INCLUDING GLH/GWO/JAN/HKS. GTR/MEI/HBG/PIB CAN EXPECT TSTM COVERAGE
THIS AFTN TO BE SIMILAR TO WHAT HAS BEEN EXPERIENCED THE PAST FEW
DAYS. MAINLY VFR CONDITIONS WILL FOLLOW TODAY AND THROUGH MOST OF
TONIGHT BEFORE THE REDEVELOPMENT OF PATCHY AREAS OF FOG AND STRATUS
LATE TONIGHT INTO EARLY SATURDAY MORNING. /22/EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 95 73 94 73 / 37 20 29 17
MERIDIAN 93 73 94 71 / 44 25 30 13
VICKSBURG 96 74 95 71 / 26 18 30 18
HATTIESBURG 94 75 94 73 / 55 16 31 12
NATCHEZ 94 74 94 73 / 40 15 40 15
GREENVILLE 97 75 95 74 / 27 23 37 26
GREENWOOD 97 73 95 73 / 27 27 43 28
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...HEAT ADVISORY UNTIL 7 PM CDT SATURDAY FOR MSZ018-019-025-034-035-
040-041.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MSZ026-027-036-042-
043-047>049-053-054-059>062.
LA...HEAT ADVISORY UNTIL 7 PM CDT SATURDAY FOR LAZ007>009-015.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LAZ016-023>026.
AR...HEAT ADVISORY UNTIL 7 PM CDT SATURDAY FOR ARZ074-075.
&&
$$
17/22/EC/BK/
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
318 PM CDT Fri Aug 9 2013
.SHORT TERM: (Through Late Tonight)
Issued at 317 PM CDT Fri Aug 9 2013
Area of rain extending from central Missouri into southwest Illinois
has persisted on the north side of a side of MCV that is currently
tracking through southeast Missouri. This rain will continue to
show a slow decrease in areal coverage and intensity as the vort
moves off to the east. Focus for additional showers and
thunderstorms this evening will then shift closer to a front over
southern Missouri into southern Illinois. RAP and Local WRF shows
low level forcing persisting along and north of this front most of
the night, so will keep chances of showers and thunderstorms mainly
in areas along and south of I-44 in Missouri and I-64 in
Illinois.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 317 PM CDT Fri Aug 9 2013
Primary concern for Saturday through early next week continues to be
timing and intensity of precipitation as quasi-zonal/northwest flow
pattern continues to control our weather. Am continuing the
persistence forecast with high chance/likely pops across the eastern
Ozarks and extreme southwest Illinois, fading to low chance/slight
chance up along the I-70 corridor for Saturday. This morning`s
850mb analysis showed a strong dewpoint gradient along the I-70 with
northerly flow across northern Missouri and moist west-southwest
flow to the south of the gradient. This gradient along with the
northerly flow feeding it is probably at least partially responsible
for the lack of northward progress for today`s precipitation. All
short range guidance keeps the 850mb dewpoint gradient in basically
the same place, hence the persistence forecast. The gradient washes
out on Sunday allowing deeper moisture to filter back into the
region. However, there appears to be a general lack of dynamic
forcing on Sunday with just some weak isentropic lift on 10kt low
level southwest flow. With nothing obvious to focus convection,
will spread chance pops further north, but am not particularly
excited about going with pops higher than chance anywhere at this
time. On Monday, a strong shortwave is forecast to drop down into
the Great Lakes region which should amplify the eastern trof and
push a cold front into the mid Mississippi Valley with a
corresponding increase in pops across the area.
Medium range guidance shows a sprawling high pressure system
building down across the Upper Midwest into the Great Lakes region
late Tuesday into Wednesday. This airmass will be cooler and much
drier than is normal for mid August. 850mb temps on the GFS are
progged to be around 10-12C...which would mix down to the low to mid
70s. The ECMWF is somewhat warmer at 12-14C. Given the
discrepancy...have opted to to stick with ensemble guidance with
highs in the upper 70s to low 80s and lows in the upper 50s to low
to 60s.
Carney
&&
.AVIATION: (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1248 PM CDT Fri Aug 9 2013
Band of showers with embedded thunderstorms extending from central
MO to just south of the St. Louis metro area will continue to
slowly diminish as it moves east northeast early this afternoon.
Think northern fringe of the rain will be close enough to KSUS and
KCPS to warrant a tempo group with ceilings between 1000-2000feet.
Ceilings this low were recently observed at KUUV and KFYG. There
may still be some scattered thunderstorms redevelop this afternoon
into early this evening.
There may be some fog redevelop late tonight into early Saturday,
particularly in low lying areas. Chances will be lower farther
north where slightly drier air will be working into areas with
less rain.
Specifics for KSTL: Lambert looks like it will be just outside of
northern fringe of area of rain, so have kept with just VCSH at
this point. There may be some redevelopment of showers and
thunderstorms the rest of the afternoon, so have left the VCSH
going until 00Z. Expect rest of forecast period to be dry as
thunderstorms tonight should be well south of Lambert with
clearing skies on Saturday.
Britt
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 70 86 69 87 / 20 30 10 30
Quincy 64 82 61 85 / 10 10 10 10
Columbia 67 85 65 87 / 20 20 10 20
Jefferson City 67 85 65 87 / 20 30 10 20
Salem 67 83 64 84 / 30 30 10 30
Farmington 66 82 66 84 / 50 60 30 30
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1249 PM CDT Fri Aug 9 2013
.SHORT TERM: (Through Late Tonight)
Issued at 1010 AM CDT Fri Aug 9 2013
Rain chances will increase through late morning as vort max currently
moving into southwest Missouri continues to move northeastward. Band
of showers and thunderstorms currently extending from west of Lake
of the Ozarks to southwest of Farmington is within an area of
decent low level moisture convergence underneath increasing ascent
ahead of the vort max. This forcing will continue primarily over
central and southern Missouri through this evening. Consequently,
I have increased rain chances along and south of I-70 the rest of
the day to account for this. The latest RAP runs show that the low
level moisture convergence will persist over southern Missouri
into the evening close to the front, so may need to up chances in
the southern CWA in later forecasts.
Britt
.LONG TERM: (Tonight through Thursday)
Issued at 312 AM CDT Fri Aug 9 2013
The synoptic pattern over s sections of the FA remains essentially
unchanged tonight through Saturday, as does the seemingly non-stop
threat of showers and thunderstorms over this area. As normal,
models solutions vary in specifics but there does seem to be some
consensus that forcing of low level jet will become focused over
sw MO late tonight and into Saturday morning, although jet is much
weaker than the past few nights. So, expecting yet another
thunderstorm cluster to develop over/advect into SW Missouri
overnight, and work east into S sections of our CWA late tonight
and Saturday morning. At this time not planning any hydro
headlines due to rather weak lift and since s sections of our CWA
have been spared the extreme rains that other parts of southern
Missouri has received; nonetheless, with pwats pushing 2 inches
and given the very effective rain producing capabilities of this
airmass we will certainly be monitoring this threat.
Meanwhile...southward push of surface ridge parked over upper
Mississippi Valley will allow cooler and more stable air to work
into n sections of the CWA later tonight and Saturday. Any storms
that do form in the unstable air over the north this afternoon should
dissipate this evening, with the more stable air limiting
development during the day on Saturday.
Have continued chance POPs over southern sections of the CWA on
Saturday night and Sunday with model consensus indicating some weak
WAA/lift persisting near the weakening baroclinicity.
Eastward progression of surface ridge will allow southerly flow, and
unstable air, to return to northern sections of the CWA by Monday.
This, combined with several shortwaves pushing into area on
persistent NW flow, should mean a threat of thunderstorms for most
of the area Monday and Monday night. However, consensus of medium
range solutions do lower heights over the Great Lakes and the East
Coast as we head into midweek, which should nudge the pesky
baroclinicity a bit more to the south and west, and allow high
pressure to backdoor cooler and more stable air into the region.
Hopefully, this will provide at least temporary respite from the
wet weather in those areas that have been hard hit by flooding
over this past week.
Truett
&&
.AVIATION: (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1248 PM CDT Fri Aug 9 2013
Band of showers with embedded thunderstorms extending from central
MO to just south of the St. Louis metro area will continue to
slowly diminish as it moves east northeast early this afternoon.
Think northern fringe of the rain will be close enough to KSUS and
KCPS to warrant a tempo group with ceilings between 1000-2000feet.
Ceilings this low were recently observed at KUUV and KFYG. There
may still be some scattered thunderstorms redevelop this afternoon
into early this evening.
There may be some fog redevelop late tonight into early Saturday,
particularly in low lying areas. Chances will be lower farther
north where slightly drier air will be working into areas with
less rain.
Specifics for KSTL: Lambert looks like it will be just outside of
northern fringe of area of rain, so have kept with just VCSH at
this point. There may be some redevelopment of showers and
thunderstorms the rest of the afternoon, so have left the VCSH
going until 00Z. Expect rest of forecast period to be dry as
thunderstorms tonight should be well south of Lambert with
clearing skies on Saturday.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
1027 AM CDT Fri Aug 9 2013
.SHORT TERM: (Through Late Tonight)
Issued at 1010 AM CDT Fri Aug 9 2013
Rain chances will increase through late morning as vort max currently
moving into southwest Missouri continues to move northeastward. Band
of showers and thunderstorms currently extending from west of Lake
of the Ozarks to southwest of Farmington is within an area of
decent low level moisture convergence underneath increasing ascent
ahead of the vort max. This forcing will continue primarily over
central and southern Missouri through this evening. Consequently,
I have increased rain chances along and south of I-70 the rest of
the day to account for this. The latest RAP runs show that the low
level moisture convergence will persist over southern Missouri
into the evening close to the front, so may need to up chances in
the southern CWA in later forecasts.
Britt
.LONG TERM: (Tonight through Thursday)
Issued at 312 AM CDT Fri Aug 9 2013
The synoptic pattern over s sections of the FA remains essentially
unchanged tonight through Saturday, as does the seemingly non-stop
threat of showers and thunderstorms over this area. As normal,
models solutions vary in specifics but there does seem to be some
consensus that forcing of low level jet will become focused over
sw MO late tonight and into Saturday morning, although jet is much
weaker than the past few nights. So, expecting yet another
thunderstorm cluster to develop over/advect into SW Missouri
overnight, and work east into S sections of our CWA late tonight
and Saturday morning. At this time not planning any hydro
headlines due to rather weak lift and since s sections of our CWA
have been spared the extreme rains that other parts of southern
Missouri has received; nonetheless, with pwats pushing 2 inches
and given the very effective rain producing capabilities of this
airmass we will certainly be monitoring this threat.
Meanwhile...southward push of surface ridge parked over upper
Mississippi Valley will allow cooler and more stable air to work
into n sections of the CWA later tonight and Saturday. Any storms
that do form in the unstable air over the north this afternoon should
dissipate this evening, with the more stable air limiting
development during the day on Saturday.
Have continued chance POPs over southern sections of the CWA on
Saturday night and Sunday with model consensus indicating some weak
WAA/lift persisting near the weakening baroclinicity.
Eastward progression of surface ridge will allow southerly flow, and
unstable air, to return to northern sections of the CWA by Monday.
This, combined with several shortwaves pushing into area on
persistent NW flow, should mean a threat of thunderstorms for most
of the area Monday and Monday night. However, consensus of medium
range solutions do lower heights over the Great Lakes and the East
Coast as we head into midweek, which should nudge the pesky
baroclinicity a bit more to the south and west, and allow high
pressure to backdoor cooler and more stable air into the region.
Hopefully, this will provide at least temporary respite from the
wet weather in those areas that have been hard hit by flooding
over this past week.
Truett
&&
.AVIATION: (For the 12z TAFs through 12z Saturday Morning)
Issued at 610 AM CDT Fri Aug 9 2013
The fog that was affecting metro area TAF sites at 12Z should
continue dissipating after sunrise with VFR conditions expected by
mid-morning. Isolated to scattered showers and thunderstorms are
possible this afternoon when an upper level disturbance interacts
with a stalled frontal boundary across southern MO/IL, but confidence
in precipitation occurring at any given terminal is too low to
include a mention in the 12Z TAFs.
Specifics for KSTL: Isolated to scattered showers and
thunderstorms are possible this afternoon, but confidence in
timing and location is too low to include it in the 12Z TAF. VFR
conditions are expected outside of any thunderstorms.
42
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1234 AM CDT Fri Aug 9 2013
.UPDATE...
Issued at 929 PM CDT THU AUG 8 2013
Heavy rain threat has ended for the far southern two tier of counties
for the rest of tonight as well as Friday. Convection has sprouted
further south than the previous two nights and expect it to spread
across OK/AR tonight with a gradual shift northeast into southern
KS/MO late tonight through Friday morning. Latest NAM/RAP/local WRF
continue to show little if any QPF over the CWA tonight. HRRR has
been the best predictor of the 12-15hr period for the past several
days/nights and it too keeps the CWA basically dry. Will roll back
PoPs and go with isolated light showers overnight except increase
them over the CWA as the northern edge of the precipitation shield of
the convective complex spreads northeast.
Have also adjusted PoPs a bit on Friday to reflect the lower
confidence on rain chances. The southern CWA still retains the
highest PoPs but heavy rainfall not likely.
UPDATE Issued at 730 PM CDT THU AUG 8 2013
Relying on radar trends and HRRR which has proven to have a better
track record over the next 12 hours. Heavy rain looks like it will
shift into southern MO and out of the CWA. Will wait to see what the
00z NAM looks like before pulling the plug on the Flash Flood Watch.
For now will lower PoPs across the board with best bet for measurable
rain over the far southern counties. Sprinkles/light showers possible
through mid evening over eastern KS/west central and northwest MO.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 300 PM CDT THU AUG 8 2013
Tonight/Friday: High uncertainty exists within forecast the next 24
hours. Current model initialization have done a poor job with
short-term trends, lending to decreased confidence in solutions for
tonight into Friday. Well-defined MCV per visible satellite and
radar trends continues to spin over central Kansas. Over the past
hour, an increasing trend of echoes has been noted over portions of
Kansas, Missouri, and southern Nebraska. The coverage, persistence,
and intensity of this activity remain quite uncertain. Do not
anticipate this activity to become heavy and should only persist for
a few more hours, otherwise could have a moderate effect to going
forecast. Dry air from H7-H85 has prevented an eastward expanse to
precipitation since this morning, and models show this layer only
gradually moistening through the overnight hours. Current surface
analysis shows frontal boundary sagging southward to near the
Oklahoma-Kansas border, with profiler data showing the H85 front
just south of the forecast area. Virtually every model solution
suggests a southward shift of the heavy precipitation corridor for
tonight/Friday, and this along with current surface/profiler data,
is compelling enough to subsequently shift heavy rain axis to the
south by at least 50 miles. Current forecast places up to one inch
of rainfall in the far southern sections of the CWA, with decreasing
amounts with northward extent. Therefore, will cancel flash flood
watch for areas along Interstate 70, and continue the southern two
rows of counties as a conditional threat if a heavy rain corridor
can make it this far north. Upper disturbance over Colorado will
make its way eastward into the Central Plains tonight, but will also
begin to weaken some with time. Still, with some increase in ascent
and close proximity to surface/elevated boundaries, cannot rule out
southern sections of the forecast area receiving moderate to
occasionally heavy rainfall late tonight into Friday. Decreasing
probabilities of rain are expected after noon Friday.
.LONG TERM...(Friday Night through Thursday)
Issued at 300 PM CDT THU AUG 8 2013
Precipitation chances will focus primarily south of the forecast
area during much of the weekend as flow becomes more zonal and the
primary focus for precipitation becomes a stationary boundary near
the MO/AR border. Ongoing precipitation Friday could linger into
Friday night as the boundary sinks back to the south; afterward,
just a few stray showers and storms possibly brushing far southern
portions of the CWA will bring the only chance of precipitation
through Sunday afternoon. Temperatures this weekend will recover to
near normal with a few breaks of sunshine Saturday and surface winds
returning to the south on Sunday.
As upper-level low pressure deepens across northern Canada and the
pattern transitions into northwest flow, most models bring a weak
shortwave trough into northwest Missouri on Sunday night into early
Monday. This feature could bring in a quick shot of precipitation
and a weak frontal boundary as it pushes east southeast; however,
forcing looks fairly weak and should keep rainfall amounts low. The
boundary may again become stationary across southern Missouri and
allow rainfall chances to linger into Tuesday, but will focus
generally south of the CWA. Then for the remainder of the forecast
period, generally dry conditions are expected with the boundary
remaining south of the region and the trough in the east keeping
most northern disturbances separate from the best moisture. High
temperatures will also be a few degrees below normal next week, as a
result of the boundary remaining to the south and northwest flow
helping a bit cooler air filter down from the northern Plains.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1229 PM CDT THU AUG 8 2013
VFR conditions will continue through the TAF period with mid level
clouds between 6-10kft. A complex of thunderstorms across northern
Oklahoma will spread northeast into southeastern Kansas overnight
into tomorrow morning. These showers may spread as far north as MCI
and MKC by tomorrow afternoon however model consensus keeps
precipitation south of the terminals. However, did keep VCSH at MKC
and MCI tomorrow afternoon. Winds during the TAF period will be light
out of the northeast.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...Blair
LONG TERM...Laflin
AVIATION...73
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
830 PM MDT SAT AUG 10 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
SENT ANOTHER UPDATE TONIGHT TO REFLECT THE QUICKLY CHANGING
WEATHER CONDITIONS. MOST OF THE CONVECTIVE ACTIVITY HAS EXITED OUR
CWA...ASIDE FROM A FEW LINGERING THUNDERSTORMS OVER THE SIDNEY
REGION. MODELS ALSO HINTING THAT THERE MAY BE SOME PATCHY FOG OVER
SOME AREAS WITH CLEARING SKIES TONIGHT SO DECIDED TO INCLUDE THAT
IN THE GRIDS WHERE EXPECTED SURFACE RELATIVE HUMIDITIES WILL BE
THE GREATEST. BMICKELSON
5PM UPDATE...
SHOWERS AND THUNDERSTORMS ARE BEGINNING TO WANE LATE THIS
AFTERNOON ACROSS NORTHEAST MONTANA. THEREFORE...AT THIS TIME IT
ALSO APPEARS THAT THE THREAT FOR STRONG THUNDERSTORMS IS
BEGINNING TO COME TO AN END. KEPT SCATTERED THUNDERSTORMS FOR THE
SOUTHEAST WHERE RADAR INDICATIONS SHOW MOST CONCENTRATED ACTIVITY
STILL LOCATED. WHILE SMALL HAIL OR BRIEF GUSTY WINDS ARE STILL
POSSIBLE...MOST OF THIS ACTIVITY IS QUICKLY SLIDING EASTWARD INTO
NORTH DAKOTA. ELSEWHERE...WILL LEAVE IN ISOLATED POPS FOR NOW. A
FEW SHOWERS/THUNDERSTORMS ACROSS SOUTHWESTERN SASKATCHEWAN MAY
MAKE IT INTO WESTERN ZONES LATE THIS EVENING OR TONIGHT IF THEY
HOLD TOGETHER BUT CONFIDENCE IS LOW. WITH UPPER RIDGE ACROSS THE
WESTERN PART OF THE STATE BECOMING MORE AMPLIFIED AND TRANSLATING
FURTHER EAST...THIS ACTIVITY SHOULD CONTINUE TO DIMINISH. MALIAWCO
PREVIOUS SHORT TERM DISCUSSION...
MAIN FORECAST CHALLENGE THIS AFTERNOON AND EVENING SURROUNDS THE
CONVECTIVE POTENTIAL ACROSS NORTHEAST MONTANA WITH VIGOROUS
SHORTWAVE DROPPING DOWN FROM SASKATCHEWAN. PERSISTENT GENERAL
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING THROUGHOUT THE
NORTHEASTERN ZONES SINCE LATE THIS MORNING. A FEW OF THESE STORMS
HAVE PRODUCED SMALL HAIL AND BRIEF HEAVY DOWNPOURS. BEST
INSTABILITY WITH HIGHEST CAPE VALUES APPEAR TO BE IN THE
SOUTHEASTERN PORTIONS OF THE CWA. HOWEVER...MODEL FORECAST
SOUNDINGS SHOW A CAP IN PLACE. IN ADDITION...HIGH CLOUDINESS HAS
FILTERED OUT SOME SUNSHINE EARLY THIS AFTERNOON REDUCING
INSOLATION. THIS PLACES A BIG QUESTION MARK IN THIS PART OF THE
FORECAST. ANY STORMS THAT DEVELOPED IN THIS AREA WERE EXPECTED TO
BECOME STRONG. IT IS STILL UNCLEAR HOW THE LATE AFTERNOON AND
EVENING WILL UNFOLD. MODEL GUIDANCE CONTINUES TO SHOW SUPPORT FOR
CONVECTION BUT RECENT HRRR SOLUTIONS HAVE BACKED DOWN JUST A BIT.
WILL KEEP THE FORECAST GOING FOR NOW AS IS BUT WILL NEED TO
MONITOR FOR CHANGES. GIVEN INSTABILITY...ANY STORMS THAT DEVELOP
AND/OR PUSH INTO THE SOUTHEAST LATER THIS AFTERNOON OR EVENING MAY
BE CAPABLE OF SMALL HAIL AND GUSTY WINDS. CUMULUS FIELD
BEGINNING TO SHOW UP IN VISIBLE SATELLITE IMAGERY ACROSS RICHLAND
COUNTY. THERE WAS MUCH MORE IN THE WAY OF SUNSHINE IN
RICHLAND...NORTHERN DAWSON...AND NORTHERN WIBAUX COUNTY AND THIS
IS THE AREA THAT WILL NEED TO BE WATCHED MOST CLOSELY FOR STRONGER
STORMS. NOT GOING TO INTRODUCE SEVERE WORDING INTO THE GRIDS AS
THERE IS JUST TOO MUCH UNCERTAINTY. IN ADDITION...SPC SSEO
SUGGESTS SEVERE POTENTIAL WOULD BE FURTHER SOUTH AND EAST OF THE
FORECAST REGION. WILL NOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM
TODAY BUT POTENTIAL FOR THAT SHOULD BE BETTER TO THE SOUTH AND
EAST OF THE CWA. ASIDE FROM THE ROBUST SHORTWAVE PUSHING THROUGH FROM
SASKATCHEWAN...ADDITIONAL SHOWERS/THUNDERSTORMS ARE POSSIBLE
ACROSS PHILLIPS COUNTY WITH A VERY WEAK SHORTWAVE EMBEDDED IN THE
UPPER FLOW PATTERN PUSHING THROUGH THIS EVENING. WILL KEEP
ISOLATED SHOWERS/STORMS IN THOSE LOCATIONS THIS EVENING.
SUNDAY INTO MONDAY...10/12Z MODEL GUIDANCE CONTINUES TO BRING UPPER
RIDGE CLOSER INTO THE CWA. THIS SHOULD PROMOTE LARGE SCALE
SUBSIDENCE. WILL NOT RULE OUT DIURNALLY DRIVEN CONVECTION BUT WITH
LITTLE MOISTURE AND NOT LIFTING MECHANISM...NOTHING MORE THAN
ISOLATED IS ANTICIPATED. TEMPERATURES SHOULD ALSO GRADUALLY
INCREASE WITH RISING HEIGHTS AND WARMING 850MB TEMPERATURES WITH
THE RIDGE BUILDING IN. MALIAWCO
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
UPPER RIDGE GRADUALLY BUILDS INTO MONTANA DURING THE EXTENDED
PERIOD.
FOR TUESDAY AND WEDNESDAY...THERE WILL BE A SLOW MOVING WARM FRONT
WHICH WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS AT TIMES.
THE STORMS WILL BE PARTLY DRIVEN BY DAYTIME INSTABILITY AND PARTLY
DRIVEN BY SHORTWAVES THAT OVERTOP THE RIDGE AXIS. MODELS TIME THE
WAVES DIFFERENTLY WHICH RESULTS IN MODELS TIMING THE STORMS
DIFFERENTLY. AT THIS POINT... IT LOOKS LIKE THE BEST CHANCE FOR
STORMS WILL BE WEDNESDAY AFTERNOON AND EVENING WHEN THE WARM FRONT
IS OVER EASTERN MONTANA. IT MAY BE UNSTABLE ENOUGH FOR SEVERE
STORMS ON WEDNESDAY. THE CHANCES OF SHOWERS AND THUNDERSTORMS
COULD LINGER INTO THURSDAY DEPENDING ON HOW FAST THE FRONT MOVES
EAST.
BY FRIDAY...THE UPPER RIDGE TAKES CONTROL OF THE WEATHER.
TEMPERATURES WILL WARM TO NEAR 90 POSSIBLY WARMER BOTH FRIDAY AND
SATURDAY WITH LITTLE OR NO CHANCE OF PRECIPITATION. FORRESTER
&&
.AVIATION...
VFR. AN ISOLATED THUNDERSTORM COULD IMPACT KSDY...BRIEFLY BRINGING
MVFR CONDITIONS IN TSRA THROUGH 04Z. OTHERWISE EXPECT MOSTLY CLEAR
SKIES AND LIGHT WINDS OVERNIGHT TONIGHT INTO MIDDAY SUNDAY.
GILCHRIST
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
519 PM MDT SAT AUG 10 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
5PM UPDATE...
SHOWERS AND THUNDERSTORMS ARE BEGINNING TO WANE LATE THIS
AFTERNOON ACROSS NORTHEAST MONTANA. THEREFORE...AT THIS TIME IT
ALSO APPEARS THAT THE THREAT FOR STRONG THUNDERSTORMS IS
BEGINNING TO COME TO AN END. KEPT SCATTERED THUNDERSTORMS FOR THE
SOUTHEAST WHERE RADAR INDICATIONS SHOW MOST CONCENTRATED ACTIVITY
STILL LOCATED. WHILE SMALL HAIL OR BRIEF GUSTY WINDS ARE STILL
POSSIBLE...MOST OF THIS ACTIVITY IS QUICKLY SLIDING EASTWARD INTO
NORTH DAKOTA. ELSEWHERE...WILL LEAVE IN ISOLATED POPS FOR NOW. A
FEW SHOWERS/THUNDERSTORMS ACROSS SOUTHWESTERN SASKATCHEWAN MAY
MAKE IT INTO WESTERN ZONES LATE THIS EVENING OR TONIGHT IF THEY
HOLD TOGETHER BUT CONFIDENCE IS LOW. WITH UPPER RIDGE ACROSS THE
WESTERN PART OF THE STATE BECOMING MORE AMPLIFIED AND TRANSLATING
FURTHER EAST...THIS ACTIVITY SHOULD CONTINUE TO DIMINISH. MALIAWCO
PREVIOUS SHORT TERM DISCUSSION...
MAIN FORECAST CHALLENGE THIS AFTERNOON AND EVENING SURROUNDS THE
CONVECTIVE POTENTIAL ACROSS NORTHEAST MONTANA WITH VIGOROUS
SHORTWAVE DROPPING DOWN FROM SASKATCHEWAN. PERSISTENT GENERAL
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING THROUGHOUT THE
NORTHEASTERN ZONES SINCE LATE THIS MORNING. A FEW OF THESE STORMS
HAVE PRODUCED SMALL HAIL AND BRIEF HEAVY DOWNPOURS. BEST
INSTABILITY WITH HIGHEST CAPE VALUES APPEAR TO BE IN THE
SOUTHEASTERN PORTIONS OF THE CWA. HOWEVER...MODEL FORECAST
SOUNDINGS SHOW A CAP IN PLACE. IN ADDITION...HIGH CLOUDINESS HAS
FILTERED OUT SOME SUNSHINE EARLY THIS AFTERNOON REDUCING
INSOLATION. THIS PLACES A BIG QUESTION MARK IN THIS PART OF THE
FORECAST. ANY STORMS THAT DEVELOPED IN THIS AREA WERE EXPECTED TO
BECOME STRONG. IT IS STILL UNCLEAR HOW THE LATE AFTERNOON AND
EVENING WILL UNFOLD. MODEL GUIDANCE CONTINUES TO SHOW SUPPORT FOR
CONVECTION BUT RECENT HRRR SOLUTIONS HAVE BACKED DOWN JUST A BIT.
WILL KEEP THE FORECAST GOING FOR NOW AS IS BUT WILL NEED TO
MONITOR FOR CHANGES. GIVEN INSTABILITY...ANY STORMS THAT DEVELOP
AND/OR PUSH INTO THE SOUTHEAST LATER THIS AFTERNOON OR EVENING MAY
BE CAPABLE OF SMALL HAIL AND GUSTY WINDS. CUMUMULUS FIELD
BEGINNING TO SHOW UP IN VISIBLE SATELLITE IMAGERY ACROSS RICHLAND
COUNTY. THERE WAS MUCH MORE IN THE WAY OF SUNSHINE IN
RICHLAND...NORTHERN DAWSON...AND NORTHERN WIBAUX COUNTY AND THIS
IS THE AREA THAT WILL NEED TO BE WATCHED MOST CLOSELY FOR STRONGER
STORMS. NOT GOING TO INTRODUCE SEVERE WORDING INTO THE GRIDS AS
THERE IS JUST TOO MUCH UNCERTAINTY. IN ADDITION...SPC SSEO
SUGGESTS SEVERE POTENTIAL WOULD BE FURTHER SOUTH AND EAST OF THE
FORECAST REGION. WILL NOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM
TODAY BUT POTENTIAL FOR THAT SHOULD BE BETTER TO THE SOUTH AND
EAST OF THE CWA. ASIDE FROM THE ROBUST SHORTWAVE PUSHING THROUGH FROM
SASKATCHEWAN...ADDITIONAL SHOWERS/THUNDERSTORMS ARE POSSIBLE
ACROSS PHILLIPS COUNTY WITH A VERY WEAK SHORTWAVE EMBEDDED IN THE
UPPER FLOW PATTERN PUSHING THROUGH THIS EVENING. WILL KEEP
ISOLATED SHOWERS/STORMS IN THOSE LOCATIONS THIS EVENING.
SUNDAY INTO MONDAY...10/12Z MODEL GUIDANCE CONTINUES TO BRING UPPER
RIDGE CLOSER INTO THE CWA. THIS SHOULD PROMOTE LARGE SCALE
SUBSIDENCE. WILL NOT RULE OUT DIURNALLY DRIVEN CONVECTION BUT WITH
LITTLE MOISTURE AND NOT LIFTING MECHANISM...NOTHING MORE THAN
ISOLATED IS ANTICIPATED. TEMPERATURES SHOULD ALSO GRADUALLY
INCREASE WITH RISING HEIGHTS AND WARMING 850MB TEMPERATURES WITH
THE RIDGE BUILDING IN. MALIAWCO
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
UPPER RIDGE GRADUALLY BUILDS INTO MONTANA DURING THE EXTENDED
PERIOD.
FOR TUESDAY AND WEDNESDAY...THERE WILL BE A SLOW MOVING WARM FRONT
WHICH WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS AT TIMES.
THE STORMS WILL BE PARTLY DRIVEN BY DAYTIME INSTABILITY AND PARTLY
DRIVEN BY SHORTWAVES THAT OVERTOP THE RIDGE AXIS. MODELS TIME THE
WAVES DIFFERENTLY WHICH RESULTS IN MODELS TIMING THE STORMS
DIFFERENTLY. AT THIS POINT... IT LOOKS LIKE THE BEST CHANCE FOR
STORMS WILL BE WEDNESDAY AFTERNOON AND EVENING WHEN THE WARM FRONT
IS OVER EASTERN MONTANA. IT MAY BE UNSTABLE ENOUGH FOR SEVERE
STORMS ON WEDNESDAY. THE CHANCES OF SHOWERS AND THUNDERSTORMS
COULD LINGER INTO THURSDAY DEPENDING ON HOW FAST THE FRONT MOVES
EAST.
BY FRIDAY...THE UPPER RIDGE TAKES CONTROL OF THE WEATHER.
TEMPERATURES WILL WARM TO NEAR 90 POSSIBLY WARMER BOTH FRIDAY AND
SATURDAY WITH LITTLE OR NO CHANCE OF PRECIPITATION. FORRESTER
&&
.AVIATION...
VFR. SCATTERED THUNDERSTORMS WILL BE AFFECTING SOME OF THE AIRPORTS
THIS AFTERNOON. EXPECT GUSTY/ERRATIC WINDS...BRIEF HEAVY RAIN AND
POSSIBLY HAIL. CLEARING AND LIGHT WINDS MAY LEAD TO PATCHY FOG
LATE TONIGHT. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
306 PM MDT FRI AUG 9 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
MAIN CONCERN THIS EVENING WILL BE CONVECTIVE POTENTIAL FOR THE
SOUTHERN ZONES. MAINTAINED ISOLATED MENTION...HOWEVER...BEST
INSTABILITY LOOKS TO REMAIN SOUTH OF THE FORECAST REGION. THERE IS
EXCELLENT AGREEMENT ON THIS IDEA FROM THE 12Z/09 MODEL GUIDANCE.
THE GFS IS FURTHER SOUTH BUT THE NAM/ECMWF BRINGS QPF CLOSE ENOUGH
TO THE CWA THAT LEAVING IN ISOLATED SHOWERS/THUNDERSTORMS IS
ACCEPTABLE. THIS HAS FURTHER SUPPORT FROM RECENT HRRR MODEL RUNS
AS WELL. OTHERWISE IT LOOKS LIKE IT WILL BE A QUIET EVENING ACROSS
NORTHEAST MONTANA WITH NORTHWEST FLOW ALOFT DOMINATING AS A RESULT
OF A RIDGE ACROSS THE WESTERN PORTIONS OF THE STATE.
SATURDAY INTO SATURDAY NIGHT...A MOIST UNSTABLE AIR MASS TO THE SOUTH
OF THE CWA WILL GRADUALLY LIFT NORTHWARD. CURRENT ECMWF BRINGS
OVER 1000 J/KG OF CAPE INTO PETROLEUM COUNTY AND SOUTHERN
GARFIELD. PROXIMITY TO THE RIDGE MAY KEEP ENOUGH LARGE SCALE
SUBSIDENCE IN PLACE THAT WIDESPREAD CONVECTION WOULD SEEM
UNLIKELY. GIVEN ABUNDANT CAPE HOWEVER IN THE FAR SOUTHWESTERN
ZONES...ANY STORMS THAT DO DEVELOP WOULD HAVE THE POTENTIAL TO
BECOME STRONG. THERE IS ALSO POOR AGREEMENT WITH THE MODELS AS THE
GFS IS SOMEWHAT MORE BULLISH AND THE NAM/ECMWF SHOWING LESS IN THE
WAY OF QPF...ALTHOUGH CAPE AND SOME OF THE CONVECTIVE PARAMETERS
DO POINT TO SOME OPPORTUNITY. WILL KEEP THE ENTIRE CWA IN A SLIGHT
CHANCE...WITH LOW END CHANCE POPS IN THE SOUTH COINCIDENT WITH THE
HIGHER CAPE/INSTABILITY. GIVEN POTENTIAL DRYING EFFECT FROM
NORTHWEST FLOW ALOFT AND SUBSIDENCE FROM THE RIDGE...CONVECTION
SHOULD BE ISOLATED IN NATURE. HOWEVER...WITH MID LEVEL DRY
AIR...GOOD DIRECTIONAL SHEAR...AND ABUNDANT CAPE...CANNOT RULE OUT
ONE OR TWO SEVERE STORMS IF CONVECTION INITIATION GETS GOING...ESPECIALLY
IN THE FAR SOUTHERN ZONES.
SUNDAY...THE SYNOPTIC PATTERN WILL EXHIBIT VERY LITTLE CHANGE BUT THE
RIDGE AXIS IS EXPECTED TO TRANSLATE FURTHER EAST AND CLOSER TO THE CWA.
THIS SHOULD PROMOTE LARGE SCALE SUBSIDENCE AND SHOULD KEEP CONVECTIVE
POTENTIAL VERY LIMITED. WILL NOT RULE OUT AN ISOLATED SHOWER OR
STORM DUE TO DIURNAL HEATING BUT WITH LACK OF INSTABILITY PRESENT
STORMS SHOULD NOT BECOME STRONG. TEMPERATURES ARE EXPECTED TO
REMAIN SEASONABLY COOL AS COMPARED TO AVERAGES FOR AUGUST...HOWEVER
WITH THE RIDGE BUILDING IN LATER IN THE WEEKEND...RISING HEIGHTS
WOULD FAVOR A SLOW MODERATING TREND. MUCH OF THE CWA WILL RETURN
TO SEEING HIGHS IN THE 80S BY SUNDAY. MALIAWCO
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
MODELS CONTINUE TO ADVERTISE A BIT WITH INCREASED INSTABILITY ABOUT
MIDWEEK. IT MAY BE A BIT EARLY BUT WENT AHEAD AND MADE MENTION OF IT
IN THE HWO. REST OF FORECAST LOOKED GOOD. MODELS ARE BEGINNING TO
SHOW SIGNS OF A STRONGER RIDGE OF HIGH PRESSURE FOR LATE NEXT
WEEK...RESULTING IN TEMPERATURES THAT MAY HIT 90 IN PLACES. TFJ
PREVIOUS DISCUSSION...
THE LONG TERM FORECAST PERIOD IS CHARACTERIZED BY A VERY GRADUAL
BUT CONSISTENTLY STRENGTHENING UPPER LEVEL RIDGE ACROSS THE ROCKY
MOUNTAIN AND HIGH PLAINS REGIONS. THIS WILL SLOWLY PUSH THE LOW
PRESSURE SYSTEM OVER THE PACIFIC NORTHWEST COAST FURTHER NORTH
BEFORE IT JOINS WITH THE LARGER SCALE LOW PRESSURE SYSTEM FROM THE
GULF OF ALASKA BY MID WEEK.
THE SPLIT FLOW OVER THE ROCKY MOUNTAINS QUICKLY REJOINS ON THE LEE
SIDE. THIS IS WHERE THE FORECAST GETS A LITTLE DIFFICULT. BY
THURSDAY OVER MONTANA...THE UPPER LEVEL FLOW SHOWS MORE ZONAL WITH
SOME SUBTLE...UNCERTAIN...AND SMALL SCALE DISTURBANCES TRYING TO
MAKE THEIR WAY THROUGH THE SPLIT FLOW.
MODEL OUTPUTS ALSO INDICATE THE FORECAST COMPLEXITIES WITH THIS BY
CONTINUING TO SHOW DIFFERING SOLUTIONS. GENERALLY SPEAKING...WHERE
THE GFS SHOWS DRY...THE EC SHOWS WET AND VICE VERSA.
GRANTED...LARGE SCALE FORCING FOR ASCENT SHOWS VIRTUALLY NO
ACTIVITY WHAT SO EVER. SO IF ANY PRECIPITATION SYSTEMS MOVE
THROUGH THE REGION...THE IMPACTS ARE EXPECTED TO BE MINIMAL WITH
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.
TEMPERATURES ARE EXPECTED TO GRADUALLY WARM TO NEAR NORMAL LEVELS
FOR THIS TIME OF YEAR. BMICKELSON
&&
.AVIATION...
VFR. GOOD FLYING CONDITIONS THROUGH THE NEXT 24 HOURS. HIGH CLOUDS
FROM THUNDERSTORMS TO OUR SOUTHWEST SHOULD BE ALL THAT MOVES IN
LATER TONIGHT. EAST WINDS WILL REMAIN LIGHT. STORMS LATE SATURDAY
COULD MOVE A BIT CLOSER...BUT NOT ENOUGH TO AFFECT FLIGHT
OPERATIONS. TFJ
&&
.CLIMATE...
SO FAR AUGUST HAS AVERAGED MORE THAN 6 DEGREES BELOW NORMAL IN THE
GLASGOW AREA. THE AVERAGE HIGH TEMPERATURE (AT LEAST FOR GLASGOW)
WILL BEGIN TO DROP SATURDAY WHILE WE SHOULD SEE WARMER CONDITIONS
RETURN NEXT WEEK. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
344 PM CDT FRI AUG 9 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI AUG 9 2013
THE PRIMARY ISSUES DURING THE NEXT 24 HOURS INVOLVES ISOLATED AND
LIKELY NON-SEVERE SHOWER/STORM DEVELOPMENT INTO THIS
EVENING...AND WHETHER OR NOT ANY IMPACTFUL FOG MIGHT DEVELOP AGAIN
OVERNIGHT. HAVE MAINTAINED A SHOWER/STORM-FREE FORECAST CWA-WIDE
FROM LATE THIS EVENING THROUGH SATURDAY AFTERNOON.
20Z OBJECTIVE SURFACE ANALYSIS REVEALS A VERY SUBTLE...WEAK COLD
FRONT ALIGNED GENERALLY EAST-WEST ACROSS THE HEART OF THE NEB
CWA...ALTHOUGH ONE HAS TO LOOK PRETTY TO FIND IT...AS ALL IT
REALLY DOES IS SEPARATE A LIGHT EAST-NORTHEAST BREEZE FROM A LIGHT
EAST TO EAST-SOUTHEAST ONE. THIS LIGHT FLOW WITH SUSTAINED BREEZES
MOST ALL AREAS NO MORE THAN 5-10 MPH IS A RESULT OF BROAD SURFACE
HIGH PRESSURE OVER THE REGION...WITH THE CORE OF THE PARENT HIGH
AROUND 1027 MILLIBARS CENTERED WELL TO THE NORTH OVER
SASKATCHEWAN. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA REVEALS RATHER WEAK FLOW ALOFT OVER THE CWA...GENERALLY
WESTERLY UP AT 300MB...NORTHERLY AT 500 MB...AND EVEN FARTHER DOWN
FROM THE EAST-NORTHEAST AT 700MB. ON THE LARGE SCALE...THE CENTRAL
PLAINS LIES IN THE INTERFACE BETWEEN A BROAD TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE TRACKING EAST ACROSS SOUTHEAST CANADA...AND A
RIDGE AXIS EXTENDING EAST-WEST ACROSS THE SOUTHERN CONUS AND THEN
NORTHWARD INTO THE ROCKIES. ON A MORE REGIONAL LEVEL...A LOW-
AMPLITUDE MID LEVEL DISTURBANCE IS LIFTING OUT ACROSS EASTERN
KS/WESTERN MO. OTHER VERY SUBTLE DISTURBANCES APPEAR TO BE
RIPPLING OUT OF THE WY AREA TOWARD WESTERN NEB/SOUTHWEST SD...AND
HELPING TO KICK OFF STORMS IN THE NORTHERN PANHANDLE.
LOCALLY...JUST WITHIN THE PAST HOUR A FEW SMALL...ISOLATED
SHOWERS/POSSIBLY WEAK STORMS HAVE BUBBLED UP OVER DAWSON/BUFFALO
COUNTIES BUT HAVE SHOWED LITTLE SIGN OF MAINTAINING ORGANIZATION.
VISIBLE SATELLITE REVEALS PARTLY TO MOSTLY CLOUDY SKIES OVER THE
CWA AT MID-AFTERNOON...WITH A DECENT LOW LEVEL CUMULUS FIELD
ACROSS MUCH OF THE CENTRAL/WEST...AND SOME LINGERING HIGH CIRRUS
STILL GRADUALLY DEPARTING EASTERN COUNTIES. HIGH TEMPS APPEAR TO
BE FAIRLY WELL ON TRACK...WITH MOST AREAS LIKELY TO END UP IN THE
81-84 RANGE.
GOING FORWARD THROUGH THE LATE AFTERNOON HOURS THROUGH
03Z/10PM...HAVE OPTED TO KEEP THINGS SIMPLE AND ADVERTISE A SLIGHT
CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS CWA-WIDE...ALTHOUGH WOULD
ANTICIPATE THE MOST LIKELY LOCALIZED DEVELOPMENT TO CONTINUE
TARGETING THE WESTERN HALF OF THE NEB CWA...WHERE LATEST MESO-
ANALYSIS INDICATES 0-1KM MLCAPE UP TO AROUND 1500 J/KG...AND WITH
LITTLE IF ANY CINH BUT ALSO VERY LIMITED FORCING FOR ASCENT. WITH
DEEP-LAYER SHEAR AVERAGING NO MORE THAN 15-20KT AND MID LEVEL
LAPSE RATES RATHER SHALLOW AT ONLY 5-6 C/KM...THE THREAT FOR
STRONG TO SEVERE STORMS APPEARS TO BE QUITE LIMITED IF NOT NON-
EXISTENT. POST-03Z/10PM...WILL AIM FOR A DRY REST OF THE
NIGHT...AS ANY DIURNAL SUPPORT FOR CONVECTION FROM AFTERNOON
HEATING WILL BE ON THE WANE...AND GIVEN THAT THE MAIN TRACK OF LOW
AMPLITUDE MID LEVEL DISTURBANCES OVERNIGHT SHOULD GENERALLY TARGET
THE NEB/SD BORDER AREA. FURTHERMORE...THE NOSE OF A MODEST 35KT
850MB LOW LEVEL JET CLEARLY AIMS INTO SOUTHERN SD/FAR NORTH CENTRAL
NEB OVERNIGHT...WHICH IS WHERE MOST MODELS INCLUDING THE NAM AND
4M WRF-NMM FOCUS CONVECTION. THAT BEING SAID...WILL HAVE TO KEEP
AN EYE ON THE NORTHWEST CWA AS THE LATEST HRRR MAINTAINS SOME
SANDHILLS CONVECTION WITHIN 50 MILES OF THE CWA THROUGH AROUND
MIDNIGHT...BUT FEEL THIS MAY BE A BIT CLOSER TO HOME THAN IT
ACTUALLY WILL BE. AT THE SURFACE TONIGHT...BREEZES WILL REMAIN
QUITE LIGHT AND AVERAGE UNDER 5 MPH...WHILE GRADUALLY TURNING TO A
SOUTHERLY DIRECTION. GIVEN THE LIGHT WIND SETUP...THERE IS AT
LEAST SOME CONCERN THAT FOG COULD AGAIN DEVELOP AND REDUCE
VISIBILITY TO 1 MILE OR LESS. HOWEVER...THE CONSENSUS OF
MODELS/GUIDANCE IS THAT TONIGHT/S FOG EVENT SHOULDN/T BE AS
DENSE/IMPACTFUL...POSSIBLY DUE TO SLIGHTLY BETTER BETTER MIXING
JUST ABOVE THE SURFACE. FOR NOW...WILL MAINTAIN THE GENERIC PATCHY
FOG MENTION CWA-WIDE FOR THE LATE NIGHT/EARLY MORNING HOURS
INTRODUCED BY THE PREVIOUS SHIFT...BUT WILL DEFER TO THE NEXT FEW
SHIFTS TO POTENTIALLY RAMP UP THIS FOG WORDING IF NEED BE. AS FOR
LOW TEMPS...ACTUALLY NUDGED DOWN 1-2 DEGREES FROM PREVIOUS IN MOST
SPOTS PER A GUIDANCE BLEND...WHICH PUTS MOST AREAS DOWN BETWEEN
57-61 DEGREES.
TURNING TO THE SATURDAY DAYTIME PERIOD 12Z-00Z/7AM-7PM...MAINTAINED
A RAIN-FREE FORECAST CWA-WIDE. IN THE MID/UPPER LEVELS...FAIRLY
WEAK TO MODEST WEST-NORTHWEST FLOW WILL MAINTAIN OVER THE CENTRAL
PLAINS AT/ABOVE 500MB...AND THERE SHOULD BE SOME SUBTLE HEIGHT
RISES AS WELL...AS THE SOUTHERN PLAINS/SOUTHERN ROCKIES RIDGE
EDGES NORTH JUST A BIT. THE PRIMARY MID LEVEL SHORTWAVE TROUGH
TRACK DURING THE DAY WILL BE FROM SD TOWARD SOUTHWEST MN/NORTHWEST
IA...AND THIS DISTURBANCE SHOULD TEAM WITH AN EAST-WEST QUASI-
STATIONARY FRONT SETTING UP NEAR THE NEB/SD BORDER TO FOCUS THE
VAST MAJORITY OF DAYTIME CONVECTION AT LEAST 50-100 MILES NORTH
AND POSSIBLY NORTHWEST OF THE CWA. THE ODDS OF CONVECTION FORMING
LOCALLY WITH DAYTIME HEATING SEEMS SMALLER THAN TODAY GIVEN
SLIGHTLY WARMER TEMPS EVIDENT AT 700MB...DESPITE MODEST MLCAPE
VALUES CLIMBING INTO THE 500-1000 J/KG RANGE PER THE 18Z NAM.
MODEL FORECASTS SOUNDINGS ALSO CLEARLY SHOW A WEAK BUT EVIDENT CAP.
OTHERWISE...ALTHOUGH BY NO MEANS WINDY...THE LATE MORNING-
AFTERNOON HOURS SHOULD FEATURE SOME OF THE MOST NOTICEABLE MODEST
BREEZES FELT IN MOST OF THE CWA IN SEVERAL DAYS...AS A TIGHTENED
PRESSURE GRADIENT TO THE EAST OF HIGH PLAINS LEE TROUGH SHOULD
PROMOTE SUSTAINED SOUTHERLY SPEEDS 10-15 MPH MOST AREAS. GIVEN THE
SOUTHERLY BREEZES...SLIGHTLY WARMER TEMPS AT 850MB...AND LIKELY NO
WORSE THAN PARTLY CLOUDY SKIES...SEE LITTLE REASON WHY HIGH TEMPS
SHOULDN/T BE AT LEAST A TOUCH HIGHER THAN TODAY. AS A
RESULT...NUDGED UP PREVIOUS HIGHS 1-2 DEGREES IN MOST AREAS...WITH
MOST OF THE CWA AIMED FOR FAIRLY UNIFORM HIGHS BETWEEN 83-86
DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM CDT FRI AUG 9 2013
GUIDANCE SUGGESTS QUASI-ZONAL TO NORTHWESTERLY MID TO UPPER LEVEL
FLOW WILL PERSIST OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG
TERM FORECAST PERIOD...WITH THE POSSIBILITY OF MULTIPLE MID LEVEL
PERTURBATIONS MOVING OVER THE AREA. PRECIPITATION CHANCES REMAIN
INTACT THROUGHOUT THE LONG TERM FORECAST PERIOD AS A RESULT.
STARTING SATURDAY NIGHT...THERE ARE SIGNS...PRIMARILY FROM THE
EC...OPERATIONAL GFS AND SREF-MEAN...THAT CENTRAL TO NORTHERN HIGH
PLAINS CONVECTION FROM SATURDAY AFTERNOON/EVENING MAY HOLD TOGETHER
LONG ENOUGH...PRIMARILY DUE TO LOW LEVEL THERMAL ADVECTION ALONG THE
AXIS OF A ~30KT 850MB JET STREAK...TO IMPACT NORTHERN PORTIONS OF
OUR CWA. CONFIDENCE IS NOT OVERLY HIGH THAT MEASURABLE PRECIPITATION
WILL BE REALIZED ACROSS OUR AREA SATURDAY NIGHT AND AS A
RESULT...POPS ONLY IN THE 20-30% RANGE CURRENTLY EXIST. HEADING INTO
THE DAY SUNDAY...LOW LEVEL CONVERGENCE ALONG A LOW LEVEL BAROCLINIC
ZONE/TROUGH COULD PROMOTE ENOUGH LIFT...ALONG WITH A PASSING MID
LEVEL PERTURBATION...TO PROMOTE PRECIPITATION PRODUCTION ACROSS
PORTIONS OF THE REGION. WHERE EXACTLY THE BOUNDARY POSITIONS ITSELF
IS THE BIGGEST QUESTION AT THIS TIME. THE NAM...EC...AND SREF-MEAN
ALL SUGGEST THE BOUNDARY WILL MOVE INTO NORTHERN OR CENTRAL PORTIONS
OF OUR CWA...WHILE THE OPERATIONAL GFS KEEPS THE BOUNDARY TO THE NORTH OF
OUR AREA. GIVEN THE UNCERTAINTY WITH RESPECT TO BOUNDARY
LOCATION...WENT NO HIGHER THAN 20-30% FOR THE DAY SUNDAY. CHANCES
FOR PRECIPITATION...ALBEIT LOW CHANCES DUE TO LOW CONFIDENCE...THEN
CONTINUE ACROSS MUCH OF OUR AREA SUNDAY NIGHT AS THE AXIS OF A
25-30KT 850MB JET STREAK DEVELOPS AND YET ANOTHER MID LEVEL
PERTURBATION POTENTIALLY MOVES OVER PORTIONS OF THE REGION. 20-30%
POPS REMAIN INTACT ACROSS THE AREA SUNDAY NIGHT AS A RESULT.
FINALLY...DURING THE DAY MONDAY...YET ANOTHER WEAK MID LEVEL
PERTURBATION MAY MOVE OVER THE AREA. CONFIDENCE IS LOW WITH RESPECT
TO ANY ONE LOCATION ACROSS THE AREA RECEIVING MEASURABLE
PRECIPITATION BUT RATHER THAN ELIMINATE POPS...WENT AHEAD AND
PRESENTED MOSTLY ~20% POPS TO MUCH OF OUR AREA FOR MONDAY.
MID LEVEL PERTURBATIONS MOVING OVER THE AREA WILL ALSO PROMOTE
CHANCES FOR PRECIPITATION ACROSS OUR AREA MONDAY NIGHT ONWARD AND AS
A RESULT...ALLBLEND PRESENTED POPS RANGING ANYWHERE FROM 20% TO 50%.
AFTER COORDINATION WITH SURROUNDING OFFICES...A FEW MINOR TWEAKS
WERE MADE TO TUESDAY POPS. OTHERWISE...ALLBLEND POPS WERE LEFT
UNCHANGED FOR THE MOST PART DUE TO THE LOW PROBABILITY OF IMPROVING
ON THE ALLBLEND SOLUTION.
DECENT LOW LEVEL MOISTURE...WITH SURFACE DEWPOINTS IN THE UPPER 60S
TO NEAR 70...WILL HELP PROMOTE RESPECTABLE LEVELS OF POTENTIAL
INSTABILITY BOTH SUNDAY AND MONDAY...WITH THE NAM AND OPERATIONAL GFS
BOTH SUGGESTING MUCAPE VALUES IN THE 2500-3500J/KG RANGE. DEEP LAYER
BULK SHEAR DOES NOT APPEAR AS THOUGH IT WILL BE OVERLY
IMPRESSIVE...GENERALLY IN THE 20-25KT RANGE...BUT GIVEN THE EXPECTED
POTENTIAL INSTABILITY WILL GO AHEAD AND OUTLOOK STRONG TO SEVERE
STORMS IN THE HWO FOR SUNDAY AND MONDAY. A SOMEWHAT DRIER LOW LEVEL
AIRMASS IS THEN EXPECTED TO INFILTRATE THE AREA TUESDAY ONWARD THUS
RESULTING IN LOWER POTENTIAL INSTABILITY VALUES. AS A RESULT...WILL
REFRAIN FROM ANY STRONG/SEVERE WEATHER WORDING IN THE HWO TUESDAY
AND BEYOND.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1248 PM CDT FRI AUG 9 2013
VFR CEILING/VISIBILITY IS ANTICIPATED FOR THE VAST MAJORITY OF THE
PERIOD...WITH THE MAIN ISSUE BEING ANOTHER POSSIBLE ROUND OF FOG
DURING THE OVERNIGHT/EARLY MORNING HOURS. AT THIS TIME...DENSE FOG
AND ASSOCIATED LIFR/VLIFR CATEGORIES ARE NOT ANTICIPATED...AND
FOR NOW WILL MAINTAIN THEME FROM PREVIOUS FORECAST OF ONLY MVFR
VISIBILITY RESTRICTIONS FROM 08Z-14Z. THIS WILL NEED CLOSELY
WATCHED HOWEVER...AS LIGHT SURFACE WINDS COULD ULTIMATELY FOSTER
WORSE CONDITIONS. OTHERWISE...IN THE NEARER TERM DURING THE NEXT 6
HOURS OR SO...A SCATTERED TO POTENTIALLY BROKEN CUMULUS FIELD
COULD FLIRT WITH HIGH-END MVFR LEVELS...BUT SHOULD PREVAIL NO
WORSE THAN LOWER VFR HEIGHTS. ITS NOT OUT OF THE QUESTION THAT A
ROGUE SHOWER/THUNDERSTORM COULD FLARE UP THIS AFTERNOON INTO EARLY
THIS EVENING...BUT THE LIKELIHOOD/ANTICIPATED COVERAGE DOES NOT
EVEN SEEM TO WARRANT A VCSH/VCTS MENTION AT THIS TIME. SURFACE
WINDS WILL AVERAGE UNDER 10KT THROUGH THE ENTIRE PERIOD...BUT
START TO PICK UP SLIGHTLY FROM THE SOUTH TOWARD THE VERY END OF
THE PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1251 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1248 PM CDT FRI AUG 9 2013
RECENTLY COMPLETED A FAIRLY MINOR UPDATE. PRECIP-WISE...DELAYED
THE SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDER FOR THE MAJORITY OF
THE CWA UNTIL POST-20Z/3PM. HIGH TEMP- WISE...MADE VERY MINOR 1-2
DEGREE ADJUSTMENTS/MAINLY DOWNWARD/IN MOST NEB ZONES...WITH MORE
OF A 3-5 DEGREE DOWNWARD BUMP IN SOME KS ZONES ESPECIALLY
OSBORNE/MITCHELL COUNTY AREA TO ACCOUNT FOR THICKER HIGH/MID LEVEL
CLOUD COVER. SHALLOW CUMULUS FIELD IS QUICKLY BLOSSOMING IN THE
CLEARING ACROSS MUCH OF THE NORTHWEST 1/4 OF THE CWA...AND TIME
WILL TELL IF THESE ACTUALLY CAN FLARE UP INTO ISOLATED SHOWERS
/NON-SEVERE STORMS.
UPDATE ISSUED AT 1032 AM CDT FRI AUG 9 2013
DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE BY 10 AM AS EXPECTED.
PLENTY OF MID-HIGH CLOUDS CONTINUE TO STREAM NORTH INTO ESPECIALLY
THE CENTRAL/EASTERN CWA FROM A SHORTWAVE TROUGH CENTERED OVER
SOUTHERN/EASTERN KS...AND THIS COULD VERY WELL CONTINUE TO PROMOTE
MOSTLY CLOUDY SKIES WELL INTO THE AFTERNOON HOURS ESPECIALLY EAST
OF HIGHWAY 281...WITH AREAS FARTHER WEST SEEING INCREASING
SUNSHINE. THIS COULD MESS WITH CURRENTLY-ADVERTISED HIGH TEMPS A
BIT AND KEEP SOME PLACES DOWN CLOSER TO 80 VERSUS MID-80S...BUT
WILL STAY THE COURSE FOR NOW AND TAKE ANOTHER LOOK AROUND MID-DAY.
PRECIP-WISE...SLASHED ALL MENTION OF RAIN THROUGH 18Z/1PM EXCEPT
FOR A SLIGHT CHANCE OF SPRINKLES IN OUR FAR SOUTHERN KS ZONES IN
CASE SOMETHING CAN WORK NORTH FROM THE MORE ORGANIZED ACTIVITY IN
CENTRAL KS. FOR THIS AFTERNOON...ODDS ARE PRETTY HIGH THAT THE
VAST MAJORITY OF THE CWA REMAINS DRY...BUT WITH A FAIRLY WEAKLY
CAPPED AIRMASS AND ROUGHLY 500-1000 J/KG 0-1 KM MIXED-LAYER CAPE
PROGGED TO BUILD PER THE LATEST RAP/NAM...HIGHEST IN THE
WEST...HELD ONTO A SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDER THIS
AFTERNOON FOR ALL BUT THE FAR NORTHEASTERN FEW COUNTIES. AS HAS
BEEN THE CASE OF LATE...THIS MODEST CAPE IS DISTRIBUTED IN A
TALL/SKINNY PROFILE WITH MID LEVEL LAPSE RATES ONLY AROUND 6
C/KM...SO THIS SHOULD GREATLY MINIMIZE ANY SEVERE WEATHER
THREAT...ALONG WITH DEEP-LAYER SHEAR ONLY AROUND 20KT OR LESS.
UPDATE ISSUED AT 746 AM CDT FRI AUG 9 2013
THE DENSE FOG ADVISORY HAS BEEN EXPANDED TO INCLUDE SEVERAL MORE
NEBRASKA COUNTIES...BASICALLY EVERYBODY ALONG/SOUTH OF INTERSTATE
80 AND ALSO SHERMAN/HOWARD. AREA AIRPORT OBS AND NDOR WEBCAMS
CLEARLY REVEAL AT LEAST LOCALLY DENSE FOG HAS EXPANDED EASTWARD
INTO THE YORK/AURORA AREAS...AND ALSO AT LEAST INTO NORTHERN
PORTIONS OF COUNTIES BORDERING THE STATE LINE...AS EVIDENCED BY
THE WEB CAM NEAR CAMPBELL. ITS CERTAINLY NOT A SOLID BLANKET OF
DENSE FOG ACROSS THE ENTIRE EXPANDED ADVISORY AREA...BUT ENOUGH
TO JUSTIFY THE HEADLINE FOR THE MORNING COMMUTE. EXPECTING
VISIBILITY TO IMPROVE CONSIDERABLY BY THE 9-10 AM HOUR...AS
SUPPORTED BY THE LATEST HRRR VISIBILITY PROG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN CHALLENGE WILL BE DETERMINING CHANCES OF PRECIPITATION AND
DENSE FOG THIS MORNING. THE LARGE SCALE PATTERN INCLUDES AN UPPER
CLOSED LOW SOUTH OF HUDSON BAY WITH A TROUGH EXTENDING INTO THE
GREAT LAKES AND OHIO VALLEY AND ALSO A CLOSED OVER THE CALIFORNIA
COAST. SOME DENSE FOG HAS DEVELOPED AS A RESULT OF LOW DEWPOINT
DEPRESSIONS AND CALM WIND...PRIMARILY IN THE WEST CENTRAL
CWA...INCLUDING THE TRI- CITIES OF KEARNEY...HASTINGS...AND GRAND
ISLAND. THE FOG SHOULD BURN OFF BY MID-MORNING AS MIXING ENSUES. A
FRONTOLYTIC SURFACE BOUNDARY WILL CONTINUE TO SAG THROUGH THE
VICINITY OF THE CWA TODAY INTO THIS EVENING...WHICH WILL PROVIDE A
FOCUS FOR SOME CONVECTION...ALTHOUGH NOT A HUGE AMOUNT OF SUPPORT.
AS INSTABILITY DECREASES AFTER SUNSET...SO WILL THE SHOT AT SOME
ISOLATED CONVECTION. ALSO...IN THE SOUTHERN CWA...THIS AREA MAY BE
CLOSE ENOUGH TO BE IN A MID- LEVEL FRONTOGENETIC AREA FROM
ACTIVITY IN THE SOUTH TO GET SOME CONVECTION GOING. THERE WILL
PROBABLY NOT BE ENOUGH INSTABILITY FOR THUNDER UNTIL THIS
AFTERNOON AND EVENING...BUT NOT ENOUGH TO SUPPORT SEVERE WEATHER.
STILL GOING WITH HIGHS IN THE 80S WITH THE EXPECTATION OF SOME
SUNSHINE BREAKING OUT AND KEPT SIMILAR TEMPERATURES FROM THE
PREVIOUS FORECAST FOR LOWS TONIGHT. SOME FOG IS NOT OUT OF THE
QUESTION TONIGHT AS WIND WILL BE LIGHT ONCE AGAIN...WITH A SIMILAR
TEMPERATURE AND DEWPOINT SITUATION AS THIS MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD WITH
A SERIES OF UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND BRING
MULTIPLE CHANCES FOR THUNDERSTORMS. MODELS CONTINUE TO BE SIMILAR IN
THE MAIN FEATURES...BUT THE DETAILS ARE A LITTLE DIFFERENT WITH EACH
MODEL.
SATURDAY WILL CONTINUE TO BE DRY SINCE WE WILL BE BETWEEN UPPER
LEVEL WAVES. THE FIRST WAVE TO MOVE THROUGH WILL MOVE INTO THE AREA
SATURDAY NIGHT. THERE IS A WEAK COLD FRONT ACROSS NORTHERN NEBRASKA
AND AS THE WAVE MOVES INTO THE AREA THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE FRONT. THIS SHOULD KEEP THE PRECIPITATION CONFINED
TO THE NORTHERN PART OF THE FORECAST AREA.
SUNDAY AND SUNDAY NIGHT THE SURFACE COLD FRONT DRIFTS TO THE SOUTH
AND AS AN UPPER LEVEL WAVE MOVES THROUGH THE CHANCES FOR
THUNDERSTORMS SPREAD ACROSS THE AREA. SUNDAY NIGHT APPEARS AT THIS
TIME TO BE THE BEST CHANCE FOR THUNDERSTORMS ACROSS THE AREA. A FEW
THUNDERSTORMS COULD LINGER INTO MONDAY AS THE FRONT CONTINUES TO
MOVE TO THE SOUTH.
THE NEXT UPPER LEVEL WAVE WILL MOVE INTO THE AREA MONDAY NIGHT AND
TUESDAY. ONCE AGAIN THE BETTER CHANCE FOR THUNDERSTORMS WILL BE
DURING THE NIGHT TIME. THE PERIOD TUESDAY NIGHT THROUGH THURSDAY THE
MODELS HAVE A FEW MORE DIFFERENCES. WILL KEEP SOME MAINLY LOW
CHANCES FOR THUNDERSTORMS ACROSS THE AREA. EXPECT THAT ANY
THUNDERSTORMS WILL BE FAIRLY ISOLATED.
TEMPERATURES FOR SATURDAY AND SUNDAY WILL BE FAIRLY CLOSE TO NORMAL
FOR THIS TIME OF YEAR. WITH THE COLD FRONT MOVING THROUGH SUNDAY THE
TEMPERATURES ON MONDAY WILL BE A LITTLE COOLER. THE SLIGHTLY COOLER
TEMPERATURES WILL CONTINUE THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1248 PM CDT FRI AUG 9 2013
VFR CEILING/VISIBILITY IS ANTICIPATED FOR THE VAST MAJORITY OF THE
PERIOD...WITH THE MAIN ISSUE BEING ANOTHER POSSIBLE ROUND OF FOG
DURING THE OVERNIGHT/EARLY MORNING HOURS. AT THIS TIME...DENSE FOG
AND ASSOCIATED LIFR/VLIFR CATEGORIES ARE NOT ANTICIPATED...AND
FOR NOW WILL MAINTAIN THEME FROM PREVIOUS FORECAST OF ONLY MVFR
VISIBILITY RESTRICTIONS FROM 08Z-14Z. THIS WILL NEED CLOSELY
WATCHED HOWEVER...AS LIGHT SURFACE WINDS COULD ULTIMATELY FOSTER
WORSE CONDITIONS. OTHERWISE...IN THE NEARER TERM DURING THE NEXT 6
HOURS OR SO...A SCATTERED TO POTENTIALLY BROKEN CUMULUS FIELD
COULD FLIRT WITH HIGH-END MVFR LEVELS...BUT SHOULD PREVAIL NO
WORSE THAN LOWER VFR HEIGHTS. ITS NOT OUT OF THE QUESTION THAT A
ROGUE SHOWER/THUNDERSTORM COULD FLARE UP THIS AFTERNOON INTO EARLY
THIS EVENING...BUT THE LIKELIHOOD/ANTICIPATED COVERAGE DOES NOT
EVEN SEEM TO WARRANT A VCSH/VCTS MENTION AT THIS TIME. SURFACE
WINDS WILL AVERAGE UNDER 10KT THROUGH THE ENTIRE PERIOD...BUT
START TO PICK UP SLIGHTLY FROM THE SOUTH TOWARD THE VERY END OF
THE PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1032 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1032 AM CDT FRI AUG 9 2013
DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE BY 10 AM AS EXPECTED.
PLENTY OF MID-HIGH CLOUDS CONTINUE TO STREAM NORTH INTO ESPECIALLY
THE CENTRAL/EASTERN CWA FROM A SHORTWAVE TROUGH CENTERED OVER
SOUTHERN/EASTERN KS...AND THIS COULD VERY WELL CONTINUE TO PROMOTE
MOSTLY CLOUDY SKIES WELL INTO THE AFTERNOON HOURS ESPECIALLY EAST
OF HIGHWAY 281...WITH AREAS FARTHER WEST SEEING INCREASING
SUNSHINE. THIS COULD MESS WITH CURRENTLY-ADVERTISED HIGH TEMPS A
BIT AND KEEP SOME PLACES DOWN CLOSER TO 80 VERSUS MID-80S...BUT
WILL STAY THE COURSE FOR NOW AND TAKE ANOTHER LOOK AROUND MID-DAY.
PRECIP-WISE...SLASHED ALL MENTION OF RAIN THROUGH 18Z/1PM EXCEPT
FOR A SLIGHT CHANCE OF SPRINKLES IN OUR FAR SOUTHERN KS ZONES IN
CASE SOMETHING CAN WORK NORTH FROM THE MORE ORGANIZED ACTIVITY IN
CENTRAL KS. FOR THIS AFTERNOON...ODDS ARE PRETTY HIGH THAT THE
VAST MAJORITY OF THE CWA REMAINS DRY...BUT WITH A FAIRLY WEAKLY
CAPPED AIRMASS AND ROUGHLY 500-1000 J/KG 0-1 KM MIXED-LAYER CAPE
PROGGED TO BUILD PER THE LATEST RAP/NAM...HIGHEST IN THE
WEST...HELD ONTO A SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDER THIS
AFTERNOON FOR ALL BUT THE FAR NORTHEASTERN FEW COUNTIES. AS HAS
BEEN THE CASE OF LATE...THIS MODEST CAPE IS DISTRIBUTED IN A
TALL/SKINNY PROFILE WITH MID LEVEL LAPSE RATES ONLY AROUND 6
C/KM...SO THIS SHOULD GREATLY MINIMIZE ANY SEVERE WEATHER
THREAT...ALONG WITH DEEP-LAYER SHEAR ONLY AROUND 20KT OR LESS.
UPDATE ISSUED AT 746 AM CDT FRI AUG 9 2013
THE DENSE FOG ADVISORY HAS BEEN EXPANDED TO INCLUDE SEVERAL MORE
NEBRASKA COUNTIES...BASICALLY EVERYBODY ALONG/SOUTH OF INTERSTATE
80 AND ALSO SHERMAN/HOWARD. AREA AIRPORT OBS AND NDOR WEBCAMS
CLEARLY REVEAL AT LEAST LOCALLY DENSE FOG HAS EXPANDED EASTWARD
INTO THE YORK/AURORA AREAS...AND ALSO AT LEAST INTO NORTHERN
PORTIONS OF COUNTIES BORDERING THE STATE LINE...AS EVIDENCED BY
THE WEB CAM NEAR CAMPBELL. ITS CERTAINLY NOT A SOLID BLANKET OF
DENSE FOG ACROSS THE ENTIRE EXPANDED ADVISORY AREA...BUT ENOUGH
TO JUSTIFY THE HEADLINE FOR THE MORNING COMMUTE. EXPECTING
VISIBILITY TO IMPROVE CONSIDERABLY BY THE 9-10 AM HOUR...AS
SUPPORTED BY THE LATEST HRRR VISIBILITY PROG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN CHALLENGE WILL BE DETERMINING CHANCES OF PRECIPITATION AND
DENSE FOG THIS MORNING. THE LARGE SCALE PATTERN INCLUDES AN UPPER
CLOSED LOW SOUTH OF HUDSON BAY WITH A TROUGH EXTENDING INTO THE
GREAT LAKES AND OHIO VALLEY AND ALSO A CLOSED OVER THE CALIFORNIA
COAST. SOME DENSE FOG HAS DEVELOPED AS A RESULT OF LOW DEWPOINT
DEPRESSIONS AND CALM WIND...PRIMARILY IN THE WEST CENTRAL
CWA...INCLUDING THE TRI- CITIES OF KEARNEY...HASTINGS...AND GRAND
ISLAND. THE FOG SHOULD BURN OFF BY MID-MORNING AS MIXING ENSUES. A
FRONTOLYTIC SURFACE BOUNDARY WILL CONTINUE TO SAG THROUGH THE
VICINITY OF THE CWA TODAY INTO THIS EVENING...WHICH WILL PROVIDE A
FOCUS FOR SOME CONVECTION...ALTHOUGH NOT A HUGE AMOUNT OF SUPPORT.
AS INSTABILITY DECREASES AFTER SUNSET...SO WILL THE SHOT AT SOME
ISOLATED CONVECTION. ALSO...IN THE SOUTHERN CWA...THIS AREA MAY BE
CLOSE ENOUGH TO BE IN A MID- LEVEL FRONTOGENETIC AREA FROM
ACTIVITY IN THE SOUTH TO GET SOME CONVECTION GOING. THERE WILL
PROBABLY NOT BE ENOUGH INSTABILITY FOR THUNDER UNTIL THIS
AFTERNOON AND EVENING...BUT NOT ENOUGH TO SUPPORT SEVERE WEATHER.
STILL GOING WITH HIGHS IN THE 80S WITH THE EXPECTATION OF SOME
SUNSHINE BREAKING OUT AND KEPT SIMILAR TEMPERATURES FROM THE
PREVIOUS FORECAST FOR LOWS TONIGHT. SOME FOG IS NOT OUT OF THE
QUESTION TONIGHT AS WIND WILL BE LIGHT ONCE AGAIN...WITH A SIMILAR
TEMPERATURE AND DEWPOINT SITUATION AS THIS MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD WITH
A SERIES OF UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND BRING
MULTIPLE CHANCES FOR THUNDERSTORMS. MODELS CONTINUE TO BE SIMILAR IN
THE MAIN FEATURES...BUT THE DETAILS ARE A LITTLE DIFFERENT WITH EACH
MODEL.
SATURDAY WILL CONTINUE TO BE DRY SINCE WE WILL BE BETWEEN UPPER
LEVEL WAVES. THE FIRST WAVE TO MOVE THROUGH WILL MOVE INTO THE AREA
SATURDAY NIGHT. THERE IS A WEAK COLD FRONT ACROSS NORTHERN NEBRASKA
AND AS THE WAVE MOVES INTO THE AREA THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE FRONT. THIS SHOULD KEEP THE PRECIPITATION CONFINED
TO THE NORTHERN PART OF THE FORECAST AREA.
SUNDAY AND SUNDAY NIGHT THE SURFACE COLD FRONT DRIFTS TO THE SOUTH
AND AS AN UPPER LEVEL WAVE MOVES THROUGH THE CHANCES FOR
THUNDERSTORMS SPREAD ACROSS THE AREA. SUNDAY NIGHT APPEARS AT THIS
TIME TO BE THE BEST CHANCE FOR THUNDERSTORMS ACROSS THE AREA. A FEW
THUNDERSTORMS COULD LINGER INTO MONDAY AS THE FRONT CONTINUES TO
MOVE TO THE SOUTH.
THE NEXT UPPER LEVEL WAVE WILL MOVE INTO THE AREA MONDAY NIGHT AND
TUESDAY. ONCE AGAIN THE BETTER CHANCE FOR THUNDERSTORMS WILL BE
DURING THE NIGHT TIME. THE PERIOD TUESDAY NIGHT THROUGH THURSDAY THE
MODELS HAVE A FEW MORE DIFFERENCES. WILL KEEP SOME MAINLY LOW
CHANCES FOR THUNDERSTORMS ACROSS THE AREA. EXPECT THAT ANY
THUNDERSTORMS WILL BE FAIRLY ISOLATED.
TEMPERATURES FOR SATURDAY AND SUNDAY WILL BE FAIRLY CLOSE TO NORMAL
FOR THIS TIME OF YEAR. WITH THE COLD FRONT MOVING THROUGH SUNDAY THE
TEMPERATURES ON MONDAY WILL BE A LITTLE COOLER. THE SLIGHTLY COOLER
TEMPERATURES WILL CONTINUE THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 551 AM CDT FRI AUG 9 2013
REDUCED VISIBILITY WILL BE THE BIGGEST ISSUE FOR THE FORECAST
THIS MORNING. SOME ISOLATED SHOWERS COULD OCCUR FOR THIS AFTERNOON
AND EVENING...BUT CHANCES ARE LOW ENOUGH TO NOT INCLUDE IN THE
FORECAST FOR NOW. MORE REDUCED VISIBILITY IS POSSIBLE FOR LATE
TONIGHT AGAIN...BUT PERHAPS NOT AS DENSE AS THIS MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
746 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 746 AM CDT FRI AUG 9 2013
THE DENSE FOG ADVISORY HAS BEEN EXPANDED TO INCLUDE SEVERAL MORE
NEBRASKA COUNTIES...BASICALLY EVERYBODY ALONG/SOUTH OF INTERSTATE
80 AND ALSO SHERMAN/HOWARD. AREA AIRPORT OBS AND NDOR WEBCAMS
CLEARLY REVEAL AT LEAST LOCALLY DENSE FOG HAS EXPANDED EASTWARD
INTO THE YORK/AURORA AREAS...AND ALSO AT LEAST INTO NORTHERN
PORTIONS OF COUNTIES BORDERING THE STATE LINE...AS EVIDENCED BY
THE WEB CAM NEAR CAMPBELL. ITS CERTAINLY NOT A SOLID BLANKET OF
DENSE FOG ACROSS THE ENTIRE EXPANDED ADVISORY AREA...BUT ENOUGH
TO JUSTIFY THE HEADLINE FOR THE MORNING COMMUTE. EXPECTING
VISIBILITY TO IMPROVE CONSIDERABLY BY THE 9-10 AM HOUR...AS
SUPPORTED BY THE LATEST HRRR VISIBILITY PROG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN CHALLENGE WILL BE DETERMINING CHANCES OF PRECIPITATION AND
DENSE FOG THIS MORNING. THE LARGE SCALE PATTERN INCLUDES AN UPPER
CLOSED LOW SOUTH OF HUDSON BAY WITH A TROUGH EXTENDING INTO THE
GREAT LAKES AND OHIO VALLEY AND ALSO A CLOSED OVER THE CALIFORNIA
COAST. SOME DENSE FOG HAS DEVELOPED AS A RESULT OF LOW DEWPOINT
DEPRESSIONS AND CALM WIND...PRIMARILY IN THE WEST CENTRAL
CWA...INCLUDING THE TRI- CITIES OF KEARNEY...HASTINGS...AND GRAND
ISLAND. THE FOG SHOULD BURN OFF BY MID-MORNING AS MIXING ENSUES. A
FRONTOLYTIC SURFACE BOUNDARY WILL CONTINUE TO SAG THROUGH THE
VICINITY OF THE CWA TODAY INTO THIS EVENING...WHICH WILL PROVIDE A
FOCUS FOR SOME CONVECTION...ALTHOUGH NOT A HUGE AMOUNT OF SUPPORT.
AS INSTABILITY DECREASES AFTER SUNSET...SO WILL THE SHOT AT SOME
ISOLATED CONVECTION. ALSO...IN THE SOUTHERN CWA...THIS AREA MAY BE
CLOSE ENOUGH TO BE IN A MID- LEVEL FRONTOGENETIC AREA FROM
ACTIVITY IN THE SOUTH TO GET SOME CONVECTION GOING. THERE WILL
PROBABLY NOT BE ENOUGH INSTABILITY FOR THUNDER UNTIL THIS
AFTERNOON AND EVENING...BUT NOT ENOUGH TO SUPPORT SEVERE WEATHER.
STILL GOING WITH HIGHS IN THE 80S WITH THE EXPECTATION OF SOME
SUNSHINE BREAKING OUT AND KEPT SIMILAR TEMPERATURES FROM THE
PREVIOUS FORECAST FOR LOWS TONIGHT. SOME FOG IS NOT OUT OF THE
QUESTION TONIGHT AS WIND WILL BE LIGHT ONCE AGAIN...WITH A SIMILAR
TEMPERATURE AND DEWPOINT SITUATION AS THIS MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD WITH
A SERIES OF UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND BRING
MULTIPLE CHANCES FOR THUNDERSTORMS. MODELS CONTINUE TO BE SIMILAR IN
THE MAIN FEATURES...BUT THE DETAILS ARE A LITTLE DIFFERENT WITH EACH
MODEL.
SATURDAY WILL CONTINUE TO BE DRY SINCE WE WILL BE BETWEEN UPPER
LEVEL WAVES. THE FIRST WAVE TO MOVE THROUGH WILL MOVE INTO THE AREA
SATURDAY NIGHT. THERE IS A WEAK COLD FRONT ACROSS NORTHERN NEBRASKA
AND AS THE WAVE MOVES INTO THE AREA THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE FRONT. THIS SHOULD KEEP THE PRECIPITATION CONFINED
TO THE NORTHERN PART OF THE FORECAST AREA.
SUNDAY AND SUNDAY NIGHT THE SURFACE COLD FRONT DRIFTS TO THE SOUTH
AND AS AN UPPER LEVEL WAVE MOVES THROUGH THE CHANCES FOR
THUNDERSTORMS SPREAD ACROSS THE AREA. SUNDAY NIGHT APPEARS AT THIS
TIME TO BE THE BEST CHANCE FOR THUNDERSTORMS ACROSS THE AREA. A FEW
THUNDERSTORMS COULD LINGER INTO MONDAY AS THE FRONT CONTINUES TO
MOVE TO THE SOUTH.
THE NEXT UPPER LEVEL WAVE WILL MOVE INTO THE AREA MONDAY NIGHT AND
TUESDAY. ONCE AGAIN THE BETTER CHANCE FOR THUNDERSTORMS WILL BE
DURING THE NIGHT TIME. THE PERIOD TUESDAY NIGHT THROUGH THURSDAY THE
MODELS HAVE A FEW MORE DIFFERENCES. WILL KEEP SOME MAINLY LOW
CHANCES FOR THUNDERSTORMS ACROSS THE AREA. EXPECT THAT ANY
THUNDERSTORMS WILL BE FAIRLY ISOLATED.
TEMPERATURES FOR SATURDAY AND SUNDAY WILL BE FAIRLY CLOSE TO NORMAL
FOR THIS TIME OF YEAR. WITH THE COLD FRONT MOVING THROUGH SUNDAY THE
TEMPERATURES ON MONDAY WILL BE A LITTLE COOLER. THE SLIGHTLY COOLER
TEMPERATURES WILL CONTINUE THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 551 AM CDT FRI AUG 9 2013
REDUCED VISIBILITY WILL BE THE BIGGEST ISSUE FOR THE FORECAST
THIS MORNING. SOME ISOLATED SHOWERS COULD OCCUR FOR THIS AFTERNOON
AND EVENING...BUT CHANCES ARE LOW ENOUGH TO NOT INCLUDE IN THE
FORECAST FOR NOW. MORE REDUCED VISIBILITY IS POSSIBLE FOR LATE
TONIGHT AGAIN...BUT PERHAPS NOT AS DENSE AS THIS MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ046>048-
060>064-072>077-082>087.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
219 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 133 AM CDT FRI AUG 9 2013
UPDATED THE FORECAST TO INCLUDE FOG OVERNIGHT AND EARLY SATURDAY
MORNING AS THE HRRR HAS INDICATED MORE OF A CHANCE OF
FOG...ESPECIALLY ON THE NEBRASKA SIDE...WHERE THE SKY COVER HAS
CLEARED.
UPDATE ISSUED AT 942 PM CDT THU AUG 8 2013
REMOVED THUNDERSTORMS FROM THE FORECAST TONIGHT BASED ON MODEL
INSTABILITY...AS WELL AS CURRENT RADAR AND SATELLITE TRENDS. ALSO
DECREASED POPS SIGNIFICANTLY ACROSS THE OUTLOOK AREA TONIGHT
THROUGH MID MORNING FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 427 PM CDT THU AUG 8 2013
BEEN LITTLE CHANGE IN THE OVERALL PATTERN ACROSS THE REGION...WITH
UPPER AIR AND SATELLITE DATA CONTINUING TO SHOW ZONAL FLOW IN THE
UPPER LEVELS...SET UP BETWEEN BROAD TROUGHING JUST TO THE EAST AND A
RIDGE AXIS IN PLACE OVER PORTIONS OF THE ROCKIES. BETWEEN THE
PASSAGE OF ONE UPPER LEVEL DISTURBANCE LAST NIGHT/EARLY THIS MORNING
AND ANOTHER APPROACHING FROM THE WEST...IT HAS BEEN A CLOUDY/DREARY
AND COOLER DAY ACROSS THE CWA. TEMPS HAVE BEEN HANGING OUT IN THE
70S...AND WITH SURFACE HIGH REMAINING IN PLACE ACROSS THE
AREA...WINDS CONTINUE TO BE ON THE LIGHT/VARIABLE SIDE.
LOOKING AT THE REST OF THIS AFTERNOON AND INTO THIS
EVENING/TONIGHT...THE MAIN STORY WILL CONTINUE TO LIE WITH
PRECIPITATION CHANCES. RECENT RADAR TRENDS SHOWING AN INCREASE IN
RETURNS ACROSS THE CWA ASSOCIATED WITH THAT NEXT MID/UPPER LEVEL
DISTURBANCE...WITH MODELS IN DECENT AGREEMENT WITH ITS CONTINUED
EASTWARD PASSAGE THROUGH THE REGION. INSTABILITY IS MEAGER...AND
SHEAR/LAPSE RATES ARE LOW...SO WHILE A FEW THUNDERSTORMS WILL BE
POSSIBLE...NOT EXPECTING IT TO BE WIDESPREAD AND WILL KEEP MENTION
OF SHOWERS WITH ISOLATED THUNDER.
WITH LITTLE CHANGE IN THE PATTERN THROUGH THE SHORT TERM
PERIOD...PRECIPITATION CHANCES WILL BE PRESENT AGAIN TOMORROW...WITH
MODELS SHOWING YET ANOTHER DISTURBANCE SET TO MOVE THROUGH THE
REGION. THE BETTER FOCUS LOOKS TO BE MOSTLY TO THE SOUTH...CLOSER
TO THE MAIN SFC FRONT...BUT COULD STILL AFFECT AT LEAST PORTIONS OF
THE CWA...SO KEPT POPS GOING WITH BETTER CHANCES IN OUR NC KS
COUNTIES. SURFACE HIGH PRESSURE REMAINS IN PLACE...KEEPING THE
LIGHT/VARIABLE WINDS AROUND.
AS FAR AS TEMPERATURES GO...OVERNIGHT LOWS TONIGHT EXPECTED TO AGAIN
BOTTOM OUT IN THE 60S...WITH HIGH TEMPERATURES TOMORROW FORECAST IN
THE LOWER 80S...WITH NOT AS MUCH CLOUD COVER EXPECTED AS TODAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 427 PM CDT THU AUG 8 2013
FOR THE MOST PART...THIS 6-DAY PERIOD REFLECTS LITTLE CHANGE FROM
THE PREVIOUS FORECAST...WITH MULTIPLE...LOW-CONFIDENCE RAIN
CHANCES IN THE SAT EVENING-THURSDAY TIME FRAME...BUT NOTHING THAT
STANDS OUT AS A HEIGHTENED CHANCE OF A WIDESPREAD SOAKER...LET
ALONE A HEIGHTENED RISK OF SEVERE WEATHER. IN OTHER WORDS...THE
PRESENCE OF SHOWER/THUNDERSTORM WORDING IN ALMOST EVERY FORECAST
PERIOD SHOULD NOT BE TAKEN AS A SIGN THAT ALL PLACES WILL SEE
NOTABLE RAINFALL DURING THE NEXT WEEK...ALTHOUGH LOCALIZED SPOTS
PROBABLY WILL SEE AT LEAST 1-2 INCHES. AS FOR CHANGES THAT WERE
MADE TO PREVIOUS FORECAST...BOTH LOW AND HIGH TEMPS WERE NUDGED UP
A BIT FROM FRI NIGHT-SUNDAY...AND SLIGHT POPS WERE ADDED FOR
FRIDAY EVENING. EVEN SO...HIGH TEMPS WILL CONTINUE TO AVERAGE AT
LEAST SLIGHTLY BELOW NORMAL MOST EVERY DAY...PROLONGING AN
INCREASINGLY IMPRESSIVE LACK OF HIGHER-END SUMMER HEAT THAT HAS
BEEN ONGOING SINCE JULY 23RD.
STARTING OUT FRIDAY EVENING/NIGHT...THE LARGE-SCALE SYNOPTIC
PICTURE ALOFT FEATURES FAIRLY WEAK QUASI-ZONAL FLOW PERSISTING
OVER THE REGION...AS THE CENTRAL PLAINS REMAINS IN BETWEEN A BROAD
EAST-WEST RIDGE CENTERED OVER THE SOUTHERN STATES...AND A LARGE
SCALE TROUGH EXTENDING FROM SOUTHEAST CANADA INTO THE GREAT
LAKES/NORTHEAST STATES...WHILE WELL OFF TO THE WEST A SLOW-MOVING
CLOSED LOW PERSISTS NEAR THE CA/OR COAST. AT THE SURFACE...BROAD
HIGH PRESSURE CENTERED JUST EAST OF THE AREA WILL RESULT IN VERY
LIGHT PREVAILING EASTERLY/SOUTHERLY LOW. STRONGLY CONSIDERED
LEAVING THE ENTIRE 12-HOUR PERIOD VOID OF RAIN MENTION...BUT
ENOUGH MODELS SUCH AS THE NAM/GFS AND ALSO REFLECTIVITY PER THE
12Z 4K WRF-NMM...SUGGESTED THAT IT MIGHT BE BEST TO INTRODUCE A
SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS TO ALL AREAS
DURING THE EVENING. ALTHOUGH CONFIDENCE IS CERTAINLY QUITE LOW ON
PLACEMENT...AND THUS THE BROAD-BRUSHED SLIGHT POPS ALL AREAS...SUBTLE
FORCING FROM A MID LEVEL DISTURBANCE GENERALLY TRACKING ACROSS THE
SOUTHERN CWA...AND POSSIBLY ALSO LOWER-LEVEL CONVERGENCE ALONG A
WEAK SURFACE BOUNDARY MAINLY WITHIN THE NORTHERN 1/2 OF NEBRASKA
COULD SPARK A FEW AREAS OF CONVECTION. SOME OF THIS ACTIVITY COULD
SIMPLY BE A CONTINUATION OF LATE-AFTERNOON ACTIVITY. AT ANY
RATE...WITH WEAK DEEP LAYER SHEAR AND 0-1KM MLCAPE PER THE NAM
QUICKLY DROPPING WELL UNDER 500 J/KG IN MOST AREAS POST-
00Z...CERTAINLY NOT FORESEEING A SEVERE THREAT. POST-
MIDNIGHT...KEPT THE FORECAST DRY AT LEAST FOR NOW...AS FORCING
APPEARS MINIMAL AND THE NOSE OF THE 850 MILLIBAR LOW LEVEL JET
AIMS WELL TO THE NORTH. NUDGED UP LOW TEMPS 1-2 DEGREES MOST
AREAS PER LATEST MET/MAV GUIDANCE TRENDS...WITH NEARLY ALL AREAS
LOW 60S.
SATURDAY/SATURDAY NIGHT...THE LARGE SCALE SCENE ALOFT CHANGES
LITTLE...AS DOMINANT RIDGING REMAINS TO THE SOUTH...AND PREVAILING
TROUGHING REMAINS ACROSS THE FAR WEST AND NORTHEAST CONUS. THERE
WILL CONTINUE TO BE LOW-AMPLITUDE SHORTWAVE TROUGHS WORKING
THROUGH THE LOCAL QUASI-ZONAL FLOW HOWEVER...ALTHOUGH EVEN AT THIS
RANGE MODELS ARE IN DISAGREEMENT ON THE MOST FAVORED
TRACK...ALTHOUGH THE 12Z ECMWF NOW SHOWS A FAIRLY POTENT SMALL
SHORTWAVE/POSSIBLY MCV FEATURE DRIFTING THROUGH THE NORTHERN 1/2
OF NEBRASKA. AT LEAST FOR NOW...HAVE LEFT THE DAYTIME PERIOD VOID
OF RAIN MENTION TO STAY CONSISTENT WITH LAST SEVERAL FORECAST
ISSUANCES...BUT THIS IS NOT YET A GUARANTEE TO REMAIN SO. THAT
BEING SAID...BEST CHANCES FOR AFTERNOON CONVECTION SHOULD REMAIN
AT LEAST SLIGHTLY NORTH AND/OR WEST OF THE CWA. THE LATEST NAM
SOUNDINGS SHOW DECENT 0-1KM MLCAPE OF 1000+ J/KG DEVELOPING OVER
THE AREA DURING THE AFTERNOON...BUT ALSO WITH A WEAK CAP HOLDING
THINGS AT BAY. AT THE SURFACE...ALTHOUGH BY NO MEANS
WINDY...SATURDAY MAY HAVE ONE OF THE STEADIER BREEZES OF THE
ENTIRE FORECAST...GENERALLY 10-15 MPH FROM THE SOUTH DURING THE
AFTERNOON. ASSUMING DAYTIME CONVECTION HOLDS AT BAY...THE LOW
LEVEL TEMP FIELD SUPPORTS A 1-3 DEGREE INCREASE IN HIGH TEMPS
VERSUS PREVIOUS FORECAST...AND NOW HAVE MOST AREAS 83-85...BUT
THIS IS STILL NOT AS WARM AS THE LATEST NAM/MET WOULD SUGGEST. FOR
SATURDAY NIGHT...A BIT BETTER LOW LEVEL THETA-E ADVECTION SIGNAL
SUGGESTS THAT ESPECIALLY THE NORTHERN/WESTERN CWA COULD GET IN ON
SOME STORMS. DUE TO OBVIOUS UNCERTAINTY AT THIS TIME RANGE...OPTED
TO GO AHEAD AND LEAVE PREVIOUS FORECAST ESSENTIALLY UNCHANGED FOR
NOW...WITH SLIGHT POPS ONLY CONFINED TO AREAS NORTH OF I-80. AGAIN
THINKING LITTLE IF ANY SEVERE THREAT.
SUNDAY DAYTIME THROUGH MONDAY NIGHT...20-40 POPS ARE IN PLACE ACROSS
THE ENTIRE CWA THIS ENTIRE TIME...WITH THE MAIN CONCENTRATION OF
HIGHEST 40 POPS FOCUSED ON SUNDAY NIGHT...AT LEAST FOR NOW.
AGAIN...THE MID/UPPER AIR PATTERN REMAINS NOTABLY
CONSISTENT...WITH THE CENTRAL PLAINS UNDER NEAR-ZONAL TO SLIGHTLY-
NORTHWESTERLY FLOW...BETWEEN A SOUTHERN CONUS RIDGE AND NORTHEAST
CONUS TROUGH. AS VARIOUS SMALLER-SCALE WAVES WORK THROUGH THE
FLOW...THERE COULD BE VARIOUS ROUNDS OF THUNDERSTORMS...BUT TO SAY
CONFIDENCE IS LOW IN THE DETAILS IS AN UNDERSTATEMENT. ITS
POSSIBLE THAT SUNDAY AFTERNOON INTO SUNDAY EVENING COULD FEATURE A
MARGINAL SEVERE/HEAVY RAIN THREAT...BUT WITH DEEP LAYER SHEAR
STRUGGLING TO REACH 30 KNOTS AND THIS BEING 3+ DAYS AWAY...IT
STILL SEEMS A BIT EARLY TO EVEN PINPOINT THIS TIME FRAME IN THE
HAZARDOUS WEATHER OUTLOOK. BUMPED UP HIGH TEMPS SUNDAY 1-2 MOST
AREAS...MAINLY MID 80S IN NEB AND UPPER 80S IN KS...WITH MONDAY
GENERALLY LOW 80S AND MID 80S IN THESE SAME AREAS...RESPECTIVELY.
TUESDAY THROUGH THURSDAY...20-30 POPS CONTINUE TO BLANKET THE
ENTIRE CWA THIS ENTIRE TIME...AND OBVIOUSLY LATER SHIFTS WILL HAVE
TO GRADUALLY REFINE THESE VERY MURKY RAIN CHANCES. ON THE LARGE-
SCALE...THE LATEST ECMWF/GFS ARE IN PRETTY GOOD AGREEMENT SHOWING
THE FLOW ALOFT OVER THE CENTRAL PLAINS TRANSITIONING FROM MORE
ZONAL TO MORE TRUE-NORTHWESTERLY...AS THE RIDGE STRENGTHENS AND
BUILDS NORTH OVER THE ROCKIES. THIS CONTINUES TO PLACE THE LOCAL
REGION IN THE PATH OF PERIODIC LOW AMPLITUDE SHORTWAVE
TROUGHS...THAT COULD KICK OFF CONVECTION OVERHEAD...OR ALLOW HIGH
PLAINS CONVECTION TO SURVIVE EASTWARD INTO THE AREA. SO MANY
DETAILS TO SORT OUT AS THIS TIME FRAME NEARS. TEMP-WISE...MADE
VERY LITTLE CHANGE TO PREVIOUS FORECAST...WITH HIGHS GENERALLY
LOW-MID 80S AND LOWS MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 133 AM CDT FRI AUG 9 2013
REDUCED VISIBILITY WILL BE THE BIGGEST ISSUE FOR THE FORECAST
OVERNIGHT INTO FRIDAY MORNING. SOME MODELS INDICATE THAT WE COULD
TANK DOWN TO LIFR...BUT STAYING A LITTLE MORE CONSERVATIVE DOWN TO
IFR FOR A SHORT TIME BEFORE IMPROVEMENT OCCURS. SOME ISOLATED
SHOWERS COULD OCCUR FOR FRIDAY AND FRIDAY EVENING...BUT CHANCES
ARE LOW ENOUGH TO NOT INCLUDE IN THE FORECAST FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...ADO
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT THU AUG 8 2013
.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.
BROKEN MID LEVEL CLOUDS WILL GRADUALLY SCATTER THROUGH 18Z...WITH
PERIODS OF CLEAR SKIES ALLOWING MVFR FOG TO FORM AROUND 12Z. VSBYS
COULD BRIEFLY DROP TO 2SM AT KOFK. THEN VFR CONDITIONS ARE
FORECAST FROM MID MORNING ON AS NORTH TO NORTHEAST WINDS AND
SCATTERED MID AND HIGH CLOUDS ARE EXPECTED.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 342 PM CDT THU AUG 8 2013/
DISCUSSION...
MAIN SHORT TERM CONCERN IS POPS THROUGH TONIGHT AS SCATTERED
SHOWERS CONTINUE TO DRIFT EAST ACROSS THE CWA.
LATEST WATER VAPOR IMAGERY AND LATEST RAP 500MB ANALYSIS SHOW A
LARGE UPPER LOW OVER ONTARIO WITH A RIDGE EXTENDING FROM THE FOUR
CORNERS REGION INTO BRITISH COLUMBIA. IN BETWEEN THIS...A WEAK
SHORTWAVE EXTENDS FROM EASTERN NEBRASKA INTO NORTHEAST KANSAS WITH
ANOTHER CIRCULATION IN SOUTH CENTRAL COLORADO.
THE SHORTWAVE ENERGY OVER THE REGION CONTINUES TO SUPPORT AN AREA
OF WIDELY SCATTERED SHOWERS OVER THE FORECAST AREA. THE LATEST RAP
SEEMS TO HAVE A GOOD HANDLE...ALBEIT A BIT OVERDONE ON QPF...AND
HAVE FOLLOWED MORE CLOSELY TO ITS TRENDS. UPPER LEVEL SUPPORT WILL
MOVE OUT OF THE AREA EARLY THIS EVENING SO HAVE ONLY CARRIED A
MENTION OF PCPN THROUGH THIS TIME. DID CONTINUE A MENTION OF SMALL
POPS IN THE FAR SOUTHEAST AFTER 06Z WITH SOME WEAK UPPER LEVEL
SUPPORT REMAINING INTO THE MORNING.
FRIDAY CONTINUES TO LOOK MOSTLY DRY BUT DID KEEP A SMALL POP IN
FOR THE SOUTH WITH SOME WEAK UPPER LEVEL SUPPORT IN THE AREA.
WITH MID/UPPER LEVEL FLOW OUT OF THE NORTHWEST THROUGH THE
WEEKEND...AND INCREASING WAA REGIME...WILL KEEP SOME SCATTERED
POPS ACROSS THE AREA...MAINLY IN THE NORTH. A STRONGER SHORTWAVE
WILL SLIDE ACROSS SOUTH DAKOTA THROUGH THE NORTHWEST FLOW
SATURDAY...SO BEST CHANCES WILL BE IN THE NORTH...ALTHOUGH WE
SHOULD NOTE THAT THE NEW 12Z ECMWF IS TRENDING THIS WAVE A BIT
FARTHER SOUTH.
ON AND OFF AGAIN SHOWERS AND TSTMS CANNOT BE RULED OUT THROUGH THE
EXTENDED WITH WEAK UPPER LEVEL SUPPORT SLIDING THROUGH THE REGION.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
650 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL KEEP A MOIST AIR MASS IN
PLACE OVER THE CAROLINAS TODAY. A COLD FRONT WILL MOVE INTO THE
REGION THIS WEEKEND... THEN STALL OVER THE AREA INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
THIS MORNING...
PATCHY CIRRUS IS MOSTLY DISSIPATING OVERHEAD...WITH PARTLY CLOUDY
SKIES OBSERVED OVER THE WESTERN CWA AND NEARLY CLEAR CONDITIONS OVER
THE EAST. A LIGHT SOUTHERLY WIND CONTINUES TO STIR OVER MUCH OF THE
CWA...BUT WHERE WINDS GO CALM...SOME PATCHY FOG MAY BE POSSIBLE
AROUND SUNRISE. THE HRRR ALSO SHOWS SOME SHOWERS DEVELOPING OVER
UPSTATE SC...DRIFTING NORTHEAST INTO THE WESTERN PIEDMONT. WHILE
SOME WEAK MUCAPE ANALYZED ON THE SPC MESO-ANALYSIS WOULD SUPPORT
THIS...THERE HAVE YET TO BE ANY SIGNS OF DEVELOPMENT ON REGIONAL
RADAR.
TODAY...
AS A COLD FRONT MOVES SLOWLY THROUGH THE OHIO VALLEY REGION
TODAY...THE DEEP LAYER FLOW AHEAD OF THE FRONT WILL BECOME MORE
UNIFORM AND SOUTHWESTERLY. THE UPPER LEVEL RIDGE TO OUR SOUTHWEST
WILL CAUSE A COUPLE CONVECTIVELY INDUCED DISTURBANCES UPSTREAM TO
SHEAR OUT AND DRIFT NORTHEAST TOWARD THE MID-ATLANTIC STATES TODAY.
THIS WILL LEAVE LOW-LEVEL CONVERGENCE IN THE FORM OF A
PREFRONTAL/LEE TROUGH AS THE MAIN TRIGGER FOR SCATTERED CONVECTION
THIS AFTERNOON. PW VALUES ARE RATHER HIGH...ABOVE 2 INCHES...BUT
MID-LEVEL LAPSE RATES ARE WEAK AND MLCAPE IS FORECAST TO REMAIN
AROUND 1000 J/KG AT BEST. MOST OF THE HI-RES MODELS SHOW
DEVELOPMENT GENERALLY FROM WINSTON-SALEM TO ROXBORO BY 20Z....WHERE
THE SFC TO 850MB CONVERGENCE IS STRONGEST....DRIFTING EAST THIS
EVENING BUT DYING OFF WITH LOSS OF HEATING. THE SEABREEZE SHOULD
ALSO BE ACTIVE AGAIN...THOUGH SOUTHWESTERLY LOW-LEVEL FLOW WOULD NOT
SUPPORT A STRONG INLAND PUSH.
REGARDING HIGHS...LOW-LEVEL THICKNESSES ARE FORECAST TO BE EQUAL TO
OR GREATER THAN OBSERVED VALUES ON THURSDAY...WHICH WOULD SUPPORT
LEANING TOWARD THE WARMER MAV MOS VALUES OF UPPER 80S AND LOWERS
90S. THIS IS ALSO BE SUPPORTED BY MORE WEST-SOUTHWESTERLY
PRE-FRONTAL FLOW WITH AT LEAST A WEAK DOWNSLOPE COMPONENT.
TONIGHT...
THE COLD FRONT WILL REMAIN TO OUR NORTH TONIGHT...AND INCREASINGLY
WESTERLY 850MB FLOW SHOULD HELP TO LIMIT ANY ADDITIONAL SHOWERS OR
STORMS OVERNIGHT. A CAVEAT TO THIS COULD BE OUTFLOW FROM STORMS TO
OUR NORTH...BUT HI-RES MODELS ARENT SHOWING VERY ROBUST CONVECTION
ALONG THE MAIN FRONTAL ZONE TODAY. THUS...EXPECT MOST OF THE NIGHT
TO BE DRY AFTER MIDNIGHT...WITH MUGGY LOWS IN THE LOWER 70S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...
SATURDAY AND SATURDAY NIGHT...
THE COLD FRONT TO OUR NORTH IS FORECAST TO SLIDE SOUTH INTO NC AND
ESSENTIALLY STALL THROUGH THE WEEKEND. WITH HIGH PW VALUES AROUND 2
INCHES...MORE FOCUSED LOW-LEVEL CONVERGENCE...AND SLIGHTLY STRONGER
BUT BROAD CYCLONIC FLOW ALOFT...SHOWERS AND STORMS SHOULD BE MORE
NUMEROUS BY EARLY SATURDAY AFTERNOON. SREF PROBABILITIES INDICATE A
MUCH GREATER LIKELIHOOD OF MLCAPE ABOVE 1000 J/KG...AND WITH 25-30KT
OF 0-6KM BULK SHEAR...A FEW CLUSTERS OF STRONG STORMS WITH DAMAGING
WIND GUSTS WILL BE POSSIBLE. A GREATER THREAT MAY BE TRAINING OF
HEAVY DOWNPOURS AS THE STEERING FLOW BECOMES PARALLEL TO THE FRONT.
WILL CONTINUE WITH LIKELY POPS DURING THE DAY SATURDAY AND MAINTAIN
A CHANCE ON SATURDAY NIGHT GIVEN THAT THE FRONT AND VARIOUS OUTFLOW
BOUNDARIES WILL LINGER OVER THE CWA. THICKER CLOUD COVER AND
EARLIER CONVECTIVE INITIATION MAY HOLD TEMPS DOWN TO THE MID/UPPER
80S IN THE NORTH SATURDAY...WHILE LOWER 90S MAY BE MORE COMMON
ACROSS THE SOUTHERN PIEDMONT/COASTAL PLAIN AS THE 850MB THERMAL
RIDGE SHIFT SOUTH. SATURDAY NIGHT LOWS AGAIN IN THE LOWER 70S.
-SMITH
FOR SUNDAY/SUNDAY NIGHT: WILL BE TOUGH TO ESCAPE GETTING WET ON
SUNDAY. THE DIFFUSE FRONTAL ZONE IS LIKELY TO BE SITUATED FROM SE VA
ACROSS NW NC AND BACK NW THROUGH KY... WITH A PRECEDING TROUGH
THROUGH ERN AND SOUTH CENTRAL NC (POTENTIALLY REINFORCED BY
CONVECTIVE OUTFLOW)... WHILE MID LEVEL LONGWAVE TROUGH AMPLIFIES
SLIGHTLY THROUGH SUNDAY NIGHT. DYNAMIC FORCING FOR ASCENT IS WEAK
BUT EVIDENT AT THE MID-UPPER LEVELS... INCLUDING UPPER DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF THE WEAKENING 80 KT WESTERLY JET TO OUR
NE... SUBTLE DPVA WITH ONE WEAK MIDLEVEL WAVE SKIRTING ACROSS VA/NRN
NC SUNDAY... AND 20-30 METER MIDLEVEL HEIGHT FALLS. BUT THE SOMEWHAT
WEAK AND LARGELY WESTERLY LOW LEVEL WIND FIELD SUGGESTS THAT LIFT
ROOTED IN THE LOWER LEVELS MAY BE LIMITED TO SURFACE CONVERGENCE
ALONG THE TROUGH. DEEP LAYER BULK SHEAR IS MARGINAL AT AROUND 20-25
KTS (HIGHEST NORTH) THROUGH MUCH OF SUNDAY/SUNDAY NIGHT... BUT WITH
MLCAPE PROJECTED TO PEAK AT 1200-2000 J/KG (LOWEST NW AND HIGHEST
SE) AND CAPE IN THE MIXED-PHASE REGION TOPPING OUT AT A FAIRLY
RESPECTABLE 500-900 J/KG... A FEW STORMS COULD BECOME STRONG WITH A
RISK OF HAIL. HEAVY RAINERS AND TRAINING/SLOW-MOVING CELLS WILL ALSO
BRING ABOUT A RISK OF LOCALIZED FLOODING GIVEN PW VALUES HOLDING
AROUND 2 INCHES... AND THE WESTERLY FLOW AND HINTS AT AN INVERTED-V
PROFILE INDICATE POSSIBLE STRONG WIND GUSTS AS WELL. BELIEVE WE`LL
SEE GOOD COVERAGE OF CONVECTION EARLY ACROSS THE NORTH... RISING TO
LIKELY AND TRANSLATING SLOWLY TO THE SOUTHEAST THROUGH THE AFTERNOON
AND EVENING... BEFORE TRENDING OUT OF ALL BUT THE FAR EASTERN CWA
OVERNIGHT. HIGHS 86-91 AND LOWS 68-73.
FOR MONDAY/MONDAY NIGHT: THE SURFACE FRONT IS LIKELY TO BECOME EVEN
WEAKER AND MORE DIFFUSE OVER THE REGION MONDAY... AS IT WAITS FOR A
SECOND STRONGER COLD FRONT (ASSOCIATED WITH THE MID LEVEL SHORTWAVE
TROUGH SWINGING THROUGH SRN ONTARIO/SW QUEBEC) TO PUSH SOUTHEASTWARD
THROUGH THE GREAT LAKES/OH VALLEY TOWARD NC. WE MAY SEE ANOTHER
EARLY START TO CONVECTION ALONG THE DYING TROUGH OVER THE
CAROLINAS... AS THE GFS DEPICTS 18Z MLCAPE OF 2000-2500 J/KG AND
-10C TO -30C CAPE REACHING 1000 J/KG AREAWIDE. WHILE DYNAMIC FORCING
FOR LIFT LOOKS EVEN WEAKER MONDAY THAN ON SUNDAY... THE HIGH PW
VALUES ALONG WITH FAVORABLE THERMODYNAMICS AND THE PRESENCE OF A LOW
LEVEL FOCUS SUGGEST WE SHOULD SEE AT LEAST 50-60% COVERAGE OF
SHOWERS/STORMS IN THE AFTERNOON... PARTICULARLY OVER THE CENTRAL AND
SE PORTIONS OF THE FORECAST AREA... WINDING DOWN AS WE HEAD THROUGH
THE EVENING WITH LOSS OF HEATING AND SUBSEQUENT STABILIZATION.
MODELS DIFFER WIDELY ON THICKNESSES... LIKELY DUE IN PART TO
DIFFERENCES IN CLOUD COVER AND PRECIP COVERAGE... BUT GIVEN
EXPECTATIONS OF DECENT MID LEVEL CLOUD COVER THROUGH THIS TIME FRAME
AND POSSIBLE EARLY CONVECTION... WILL HOLD HIGH TEMPS A BIT BELOW
NORMAL... 85-89... WITH NEAR NORMAL LOWS OF 69-73. -GIH
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 310 AM FRIDAY...
EXPECT CONTINUED ABOVE-NORMAL RAIN CHANCES INTO WEDNESDAY...
FOLLOWED BY DRIER AND COOLER (POTENTIALLY MUCH SO) CONDITIONS FOR
THURSDAY. MODELS DIG THE MIDLEVEL TROUGH DOWN WELL INTO THE EASTERN
CONUS TUESDAY INTO WEDNESDAY... WITH THE SURFACE COLD FRONT PUSHING
TO OUR SOUTH WEDNESDAY. THEY THEN DEPICT THE DEVELOPMENT OF COLD AIR
DAMMING LATE WEDNESDAY AS THE SURFACE FRONT PUSHES JUST TO OUR
SOUTH WHILE CANADIAN HIGH PRESSURE SLIDES BY TO OUR NORTH... ACROSS
THE GREAT LAKES/OH VALLEY TO THE MIDATLANTIC/NORTHEAST. THE
AGREEMENT AMONG THE GFS/ECMWF/CANADIAN REGARDING THIS EVOLUTION IS
ACTUALLY FAIRLY GOOD CONSIDERING IT IS DAYS 5-7 OF THE FORECAST.
WILL KEEP A GOOD CHANCE OF SHOWERS/STORMS (HIGHER SOUTH/EAST)
TUESDAY INTO WEDNESDAY WITH TEMPS TRENDING FROM NEAR NORMAL TO JUST
BELOW NORMAL... THEN WILL GO LARGELY DRY THURSDAY BUT WITH LINGERING
CLOUD COVER AS 850 MB OVERRUNNING FLOW SHOULD RESUME BY LATE IN THE
DAY. GFS/ECMWF THICKNESSES PLUNGE TO AROUND 30 METERS BELOW NORMAL
THURSDAY... SUGGESTING HIGHS OF 77-83. -GIH
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM FRIDAY...
A NARROW OF REGION OF STRATUS HAS FORMED OVER THE COASTAL
PLAIN...STRETCHING FROM KFAY TO KRWI IS SLOWLY EXPANDING TO THE
NORTHWEST. EXPECT IFR CEILINGS TO PERSIST AT KFAY AND KRWI THROUGH
AROUND 13Z...BUT IT DOES NOT APPEAR THESE CEILINGS WILL MAKE IT ALL
THE WAY TO KRDU BEFORE DAYTIME MIXING BEGINS TO ERODE THE STRATUS.
OTHERWISE...A FEW SITES ARE REPORTING MVFR VSBYS...INCLUDING KINT.
THESE CONDITIONS WILL ALSO IMPROVE RAPIDLY AFTER 12Z.
THIS AFTERNOON...SCATTERED SHOWERS AND STORMS SHOULD DEVELOP BY
18-20Z. HI-RES MODELS SHOW CONVECTIVE DEVELOPMENT OVER THE HIGHER
TERRAIN...EVENTUALLY MOVING INTO THE NORTHWEST PIEDMONT AND
IMPACTING KGSO AND KINT. WHILE THE STORMS ARE NOT EXPECTED TO BE
SEVERE...STRONG WIND GUSTS AND BRIEF IFR/LIFR CONDITIONS WILL BE
POSSIBLE.
THE LOSS OF HEATING SHOULD BRING ALL SHOWER AND STORMS TO AN END
THIS EVENING...WITH JUST A LIGHT SOUTHWESTERLY WIND OVERNIGHT.
STRATUS WILL BE POSSIBLE AGAIN LATE TONIGHT...ALTHOUGH WITH MORE OF
A WEST-SOUTHWESTERLY WIND...LOW CEILINGS MAY AGAIN BE CONFINED TO
THE COASTAL PLAIN.
OUTLOOK...
A COLD FRONT WILL MOVE SOUTH INTO VIRGINIA AND THE CAROLINAS OVER
THE WEEKEND...EVENTUALLY STALLING AND LINGERING THROUGH EARLY NEXT
WEEK. THIS WILL BRING AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH
ABOVE AVERAGE CHANCES OF SHOWERS AND STORMS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
655 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY GIVE WAY TO A MORE UNSETTLED PATTERN FOR
THE NEXT SEVERAL DAYS. GENEROUS AMOUNTS OF RAINFALL ARE POSSIBLE
SUNDAY THROUGH MUCH OF NEXT WEEK. A COLD FRONT MAY MOVE FAR ENOUGH
SOUTH LATE NEXT WEEK TO LEAD TO DRIER CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...THE MOST RECENT HRRR RUNS ARE NOT INITIALIZING
WITH ANY OF THE OBSERVED SHOWER ACTIVITY ALONG THE CAROLINA COAST.
FOR THE NEXT SEVERAL HOURS I EXPECT TO SEE A CONTINUATION OF
SCATTERED SHOWERS DEVELOPING ALONG THE SC LANDBREEZE FRONT...MOVING
NORTHEASTWARD WITH THE MEAN LOW LEVEL FLOW. OVER LAND THE BEST
POTENTIAL FOR ADDITIONAL RAINFALL WILL BE THE SOUTHPORT/BALD HEAD
ISLAND VICINITY...WITH A SECOND BATCH OF SHOWERS RECENTLY OBSERVED
DEVELOPING JUST SOUTHWEST OF GEORGETOWN WHICH COULD AFFECT COASTAL
SOUTH CAROLINA IF THEY HOLD TOGETHER. NO CHANGES IN THINKING FOR THE
AFTERNOON AS THE SEABREEZE SHOULD DRIVE MOST OF THE PRECIPITATION
INLAND FROM THE BEACHES. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE HIGH PRESSURE OFF THE U.S. EAST COAST IS DRAWING HOT
TROPICAL AIR NORTHWARD FROM THE CARIBBEAN. THE SUBTROPICAL RIDGE AT
500 THROUGH 200 MB IS NEARLY OVERHEAD AS A WELL-DEFINED TUTT LOW
MOVES WESTWARD UNDER THE RIDGE ACROSS THE FLORIDA KEYS. 850 MB
TEMPERATURES HAVE WARMED ALMOST ANOTHER FULL DEGREE CELSIUS FROM
YESTERDAY WHICH SHOULD GUARANTEE 91-93 ACROSS MOST OF THE INTERIOR
EASTERN CAROLINAS...WITH 88-90 EXPECTED NEAR THE COAST. IT IS WORTH
NOTING THAT THE MARINE ENVIRONMENT IS RIGHT AT ITS PEAK
CLIMATOLOGICAL TEMPERATURES OF THE YEAR AS MEASURED BY SEA SURFACE
AND AIR TEMPERATURE...SO THE COOLING EFFECT PROVIDED BY THE
SEABREEZE HAS REACHED ITS MINIMUM.
STEADY SOUTH-SOUTHWEST WINDS HAVE BEEN BLOWING ALONG THE COAST ALL
MORNING. AS A LANDBREEZE DEVELOPS BETWEEN GEORGETOWN AND SOUTHPORT
AND INTERCEPTS THIS WARM AND HUMID LOW-LEVEL AIRSTREAM...EXPECT A
LINE OF TOWERING CUMULUS AND EVENTUALLY SHOWERS DEVELOP AROUND OR
SHORTLY AFTER DAYBREAK. THE LAST SEVERAL RUNS OF THE HRRR DEPICT
THIS CONVECTION MAINLY REMAINING OFFSHORE...BUT IMPACTING AT LEAST
PORTIONS OF BRUNSWICK AND NEW HANOVER COUNTIES BETWEEN 8-11 AM. AS
HEAT AND HUMIDITY BUILD INLAND LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE SEABREEZE BOUNDARY
BEGINNING BY NOON. COVERAGE SHOULD AVERAGE ABOUT 30 PERCENT OF THE
AREA DURING THE DAYLIGHT HOURS...AIDED BY STORM MOTION TOWARD THE
NORTHEAST AT 12-15 MPH AND VERY LITTLE CONVECTIVE CAPPING WITHIN AN
AIRMASS CHARACTERIZED BY CAPE 1000-1500 J/KG. THESE SHOULD BE PULSE
STORMS WITH NO SIGNIFICANT WIND OR DRY LAYERS ALOFT AND PRECIPITABLE
WATER AROUND 2.0 INCHES.
CONVECTION SHOULD FALL APART DURING THE EARLY TO MID EVENING HOURS
WITH THE LOSS OF DAYTIME HEATING. MOSTLY CLEAR SKIES ARE EXPECTED
OVERNIGHT WITH LOWS FALLING TO 73-77...WARMEST ALONG THE SOUTH-
FACING BRUNSWICK COUNTY BEACHES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...MID LEVEL RIDGE WILL SLOWLY WEAKEN THROUGH THE
PERIOD AS THE TROPOSPHERE GRADUALLY BECOMES MORE CONDUCIVE FOR
CONVECTION. AT THE SURFACE...TOUGH TO DISTINGUISH BETWEEN AN ACTUAL
FRONT OR TROUGH BUT THE FOCUS WILL BE THE IMPORTANT FACTOR.
NUMERICAL GUIDANCE REFLECTS THIS TREND WITH SLOWLY INCREASING POPS
FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON. THE OFFICIAL
FORECAST SHOWS THIS AS WELL WITH POPS INITIALLY AT SLIGHT CHANCE
TRENDING UP TO GOOD CHANCE BY SUNDAY PM. PRECIPITABLE WATER VALUES
CLIMB FROM APPROXIMATELY 1.75 INCHES SATURDAY TO NEAR 2.00 INCHES
SUNDAY.
SOME MINOR DISAGREEMENT BETWEEN THE MAV AND MET NUMBERS FOR HIGH
TEMPERATURES ESPECIALLY INLAND. WILL LEAN TOWARD THE WARMER MAV
NUMBERS SATURDAY AND SLIGHTLY COOLER MET NUMBERS SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT AN
EXTENDED PERIOD OF WET WEATHER AS TROUGHING IS IN PLACE ACROSS THE
MIDWEST AND RIDGING OUT WEST. THERE IS A SIGNAL THAT THE FRONT MAY
SLIP FAR ENOUGH SOUTH VIA THE PREFERRED ECMWF ENSEMBLE MEAN SOLUTION
FROM WPC THAT THURSDAY COULD DRY OUT A BIT. THIS IS REFLECTED IN
GRAPHICS FROM WPC AND IN OUR OFFICIAL FORECAST. WE ARE FORECASTING
HIGH CHANCE POPS AND EVEN A PERIOD...TUESDAY...OF LIKELY POPS WHICH
SEEM WARRANTED. AS MENTIONED LAST NIGHT...I BELIEVE THERE WILL BE
MORE LIKELY POPS WARRANTED AS WE DRAW CLOSER TO THE ONSET OF THE
EVENT. TEMPERATURE TRENDS REMAIN INTACT WITH DAYTIME
HIGHS...CERTAINLY MODULATED BY RAINFALL NEAR CLIMATOLOGY AND
OVERNIGHT LOWS A BIT ON THE HIGH SIDE CITING THE PREVAILING
MOISTURE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...A BIT OF A CONVERGENCE BOUNDARY WITH A WEAK LAND BREEZE
THIS MORNING. SCATTERED CONVECTION WILL OCCUR ALONG THIS BOUNDARY
THIS MORNING AS IT TRANSITIONS TO A SEA BREEZE BY LATE MORNING. A
SOUTH SOUTHWEST GRADIENT WILL CREATE GUSTY WINDS BY MIDDAY. THIS
AFTERNOON...THE PIEDMONT THERMAL TROUGH WILL SET UP...WITH SCATTERED
CONVECTION EXPECTED MAINLY DOWN THE I-95 CORRIDOR.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY
THROUGH TUESDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...SHOWER ACTIVITY GOT OFF TO AN EARLIER THAN
EXPECTED START...BUT THE REMAINDER OF THE FORECAST IS NEARLY
UNCHANGED. THE BULK OF THE SHOWERS SHOULD WRAP UP BY LATE MORNING AS
THE FOCUS FOR NEW CONVECTIVE DEVELOPMENT SHIFTS INLAND WITH THE
DEVELOPING SEABREEZE CIRCULATION. SEAS BUILT TO 3 FT RECENTLY AT
BOTH THE WILMINGTON HARBOR BUOY JUST SOUTH OF SOUTHPORT...AND AT THE
OCEAN CREST PIER WAVE GAUGE ON OAK ISLAND. I HAVE BUMPED UP THE
ONSET OF 3 FOOT SEAS BY A FEW HOURS TO MATCH OBSERVATIONS. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
HIGH PRESSURE OFF THE U.S. EAST COAST WILL MAINTAIN A
SOUTH-SOUTHWEST WIND ACROSS THE AREA TODAY AND TONIGHT. HIGH
RESOLUTION MODELS INDICATE A LANDBREEZE MAY DEVELOP ALONG THE SOUTH
CAROLINA COAST AROUND DAYBREAK...POTENTIALLY IGNITING SCATTERED
SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE MORNING HOURS. RADAR
IS CURRENTLY CLEAR...BUT THIS PATTERN OF AN EARLY MORNING LANDBREEZE
LEADING TO SHOWERS IS A TYPICAL AUGUST WEATHER SCENARIO HERE. AS
HEAT BUILDS INLAND DURING THE LATE MORNING AND AFTERNOON HOURS MOST
OF THE SHOWER ACTIVITY OVER THE OCEAN SHOULD DISSIPATE WITH A MODEST
SEABREEZE INCREASING WIND SPEEDS TO 15 KNOTS NEAR SHORE. FOR TONIGHT
SHOWER CHANCES APPEAR QUITE LOW AS SOUTH-SOUTHWEST WINDS RETURN TO A
STEADY 10-15 KNOTS.
SEAS CURRENTLY AVERAGE 2 FT NEARSHORE WITH 2.5 TO 3 FOOT SEAS
REPORTED FROM THE FRYING PAN SHOALS BUOY. SEAS SHOULD AVERAGE 2-3 FT
THROUGH TONIGHT IN A COMBINATION OF 4 SECOND WIND WAVE AND 9 SECOND
SOUTHEAST SWELL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A RELATIVELY WEAK FRONT OR SURFACE TROUGH WILL
REMAIN INLAND ALLOWING A PERSISTENT SOUTHWEST FLOW TO CONTINUE
THOUGH THE PERIOD. WIND SPEEDS WILL BE 10-15 KNOTS. IT APPEARS THERE
IS A LITTLE ENHANCEMENT OF THE LOW LEVEL WIND FIELDS OVERNIGHT
SATURDAY INTO SUNDAY MORNING WHICH WILL TILT THE SPEEDS TO THE
HIGHER END OF THE RANGE. SIGNIFICANT SEAS REMAIN UNCHANGED WITH 2-3
FEET SHORTER PERIOD WIND WAVES.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...DIFFUSE FRONT DRAPED ACROSS THE AREA WILL NOT
HAVE A SIGNIFICANT IMPACT ON THE COASTAL WATERS FORECAST AT LEAST
FROM A SYNOPTIC STANDPOINT. SOUTHWEST WINDS OF AROUND TEN KNOTS WILL
PREVAIL WITH SIGNIFICANT SEAS OF 2-4 FEET. THE WAVEWATCH GUIDANCE IS
TRENDING UP FROM 2-3 FEET MONDAY TO 2-4 FEET TUESDAY MAINLY ACROSS
THE OUTER WATERS. PERIODS SHOW WIND WAVES WHICH GIVES ME PAUSE AS
THE WIND FIELDS REMAIN WEAK BUT THE INCREASE ISN/T A SIGNIFICANT
IMPACT ON THE FORECAST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
642 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY GIVE WAY TO A MORE UNSETTLED PATTERN FOR
THE NEXT SEVERAL DAYS. GENEROUS AMOUNTS OF RAINFALL ARE POSSIBLE
SUNDAY THROUGH MUCH OF NEXT WEEK. A COLD FRONT MAY MOVE FAR ENOUGH
SOUTH LATE NEXT WEEK TO LEAD TO DRIER CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...THE MOST RECENT HRRR RUNS ARE NOT INITIALIZING
WITH ANY OF THE OBSERVED SHOWER ACTIVITY ALONG THE CAROLINA COAST.
FOR THE NEXT SEVERAL HOURS I EXPECT TO SEE A CONTINUATION OF
SCATTERED SHOWERS DEVELOPING ALONG THE SC LANDBREEZE FRONT...MOVING
NORTHEASTWARD WITH THE MEAN LOW LEVEL FLOW. OVER LAND THE BEST
POTENTIAL FOR ADDITIONAL RAINFALL WILL BE THE SOUTHPORT/BALD HEAD
ISLAND VICINITY...WITH A SECOND BATCH OF SHOWERS RECENTLY OBSERVED
DEVELOPING JUST SOUTHWEST OF GEORGETOWN WHICH COULD AFFECT COASTAL
SOUTH CAROLINA IF THEY HOLD TOGETHER. NO CHANGES IN THINKING FOR THE
AFTERNOON AS THE SEABREEZE SHOULD DRIVE MOST OF THE PRECIPITATION
INLAND FROM THE BEACHES. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE HIGH PRESSURE OFF THE U.S. EAST COAST IS DRAWING HOT
TROPICAL AIR NORTHWARD FROM THE CARIBBEAN. THE SUBTROPICAL RIDGE AT
500 THROUGH 200 MB IS NEARLY OVERHEAD AS A WELL-DEFINED TUTT LOW
MOVES WESTWARD UNDER THE RIDGE ACROSS THE FLORIDA KEYS. 850 MB
TEMPERATURES HAVE WARMED ALMOST ANOTHER FULL DEGREE CELSIUS FROM
YESTERDAY WHICH SHOULD GUARANTEE 91-93 ACROSS MOST OF THE INTERIOR
EASTERN CAROLINAS...WITH 88-90 EXPECTED NEAR THE COAST. IT IS WORTH
NOTING THAT THE MARINE ENVIRONMENT IS RIGHT AT ITS PEAK
CLIMATOLOGICAL TEMPERATURES OF THE YEAR AS MEASURED BY SEA SURFACE
AND AIR TEMPERATURE...SO THE COOLING EFFECT PROVIDED BY THE
SEABREEZE HAS REACHED ITS MINIMUM.
STEADY SOUTH-SOUTHWEST WINDS HAVE BEEN BLOWING ALONG THE COAST ALL
MORNING. AS A LANDBREEZE DEVELOPS BETWEEN GEORGETOWN AND SOUTHPORT
AND INTERCEPTS THIS WARM AND HUMID LOW-LEVEL AIRSTREAM...EXPECT A
LINE OF TOWERING CUMULUS AND EVENTUALLY SHOWERS DEVELOP AROUND OR
SHORTLY AFTER DAYBREAK. THE LAST SEVERAL RUNS OF THE HRRR DEPICT
THIS CONVECTION MAINLY REMAINING OFFSHORE...BUT IMPACTING AT LEAST
PORTIONS OF BRUNSWICK AND NEW HANOVER COUNTIES BETWEEN 8-11 AM. AS
HEAT AND HUMIDITY BUILD INLAND LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE SEABREEZE BOUNDARY
BEGINNING BY NOON. COVERAGE SHOULD AVERAGE ABOUT 30 PERCENT OF THE
AREA DURING THE DAYLIGHT HOURS...AIDED BY STORM MOTION TOWARD THE
NORTHEAST AT 12-15 MPH AND VERY LITTLE CONVECTIVE CAPPING WITHIN AN
AIRMASS CHARACTERIZED BY CAPE 1000-1500 J/KG. THESE SHOULD BE PULSE
STORMS WITH NO SIGNIFICANT WIND OR DRY LAYERS ALOFT AND PRECIPITABLE
WATER AROUND 2.0 INCHES.
CONVECTION SHOULD FALL APART DURING THE EARLY TO MID EVENING HOURS
WITH THE LOSS OF DAYTIME HEATING. MOSTLY CLEAR SKIES ARE EXPECTED
OVERNIGHT WITH LOWS FALLING TO 73-77...WARMEST ALONG THE SOUTH-
FACING BRUNSWICK COUNTY BEACHES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...MID LEVEL RIDGE WILL SLOWLY WEAKEN THROUGH THE
PERIOD AS THE TROPOSPHERE GRADUALLY BECOMES MORE CONDUCIVE FOR
CONVECTION. AT THE SURFACE...TOUGH TO DISTINGUISH BETWEEN AN ACTUAL
FRONT OR TROUGH BUT THE FOCUS WILL BE THE IMPORTANT FACTOR.
NUMERICAL GUIDANCE REFLECTS THIS TREND WITH SLOWLY INCREASING POPS
FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON. THE OFFICIAL
FORECAST SHOWS THIS AS WELL WITH POPS INITIALLY AT SLIGHT CHANCE
TRENDING UP TO GOOD CHANCE BY SUNDAY PM. PRECIPITABLE WATER VALUES
CLIMB FROM APPROXIMATELY 1.75 INCHES SATURDAY TO NEAR 2.00 INCHES
SUNDAY.
SOME MINOR DISAGREEMENT BETWEEN THE MAV AND MET NUMBERS FOR HIGH
TEMPERATURES ESPECIALLY INLAND. WILL LEAN TOWARD THE WARMER MAV
NUMBERS SATURDAY AND SLIGHTLY COOLER MET NUMBERS SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT AN
EXTENDED PERIOD OF WET WEATHER AS TROUGHING IS IN PLACE ACROSS THE
MIDWEST AND RIDGING OUT WEST. THERE IS A SIGNAL THAT THE FRONT MAY
SLIP FAR ENOUGH SOUTH VIA THE PREFERRED ECMWF ENSEMBLE MEAN SOLUTION
FROM WPC THAT THURSDAY COULD DRY OUT A BIT. THIS IS REFLECTED IN
GRAPHICS FROM WPC AND IN OUR OFFICIAL FORECAST. WE ARE FORECASTING
HIGH CHANCE POPS AND EVEN A PERIOD...TUESDAY...OF LIKELY POPS WHICH
SEEM WARRANTED. AS MENTIONED LAST NIGHT...I BELIEVE THERE WILL BE
MORE LIKELY POPS WARRANTED AS WE DRAW CLOSER TO THE ONSET OF THE
EVENT. TEMPERATURE TRENDS REMAIN INTACT WITH DAYTIME
HIGHS...CERTAINLY MODULATED BY RAINFALL NEAR CLIMATOLOGY AND
OVERNIGHT LOWS A BIT ON THE HIGH SIDE CITING THE PREVAILING
MOISTURE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A SOUTHWEST LOW LEVEL JET WITH 1000 FT AGL WIND SPEEDS
NEAR 20 KNOTS SHOULD PREVENT FOG FORMATION THROUGH DAYBREAK...BUT
COULD ACTUALLY FAVOR LOW STRATUS DEVELOPMENT INLAND. GFS AND NAM MOS
BOTH SHOW THIS POTENTIAL AT FLO AND LBT...BUT AFTER LAST NIGHT`S
BUST WITH IFR CONDITIONS FORECAST BUT NEVER OCCURRING I AM NOT SO
CERTAIN. FOR NOW I WILL ONLY INCLUDE SCATTERED LOW CLOUDS IN THE
FORECAST...BUT BE AWARE THERE IS SOME POTENTIAL FOR AN HOUR OR TWO
OF IFR CEILINGS AT BOTH FLO AND LBT...MAINLY 10-12Z.
AFTER DAYBREAK...SCATTERED CUMULUS WITH BASES 2000-3000 FT AGL
SHOULD DEVELOP WITH MODERATE SOUTHWEST LOW LEVEL WINDS GUSTING AS
HIGH AS 20 KNOTS AT THE COAST. MUCH LIKE YESTERDAY SCATTERED SHOWERS
MAY DEVELOP FIRST IN THE WILMINGTON AREA...SPREADING INLAND WITH THE
AFTERNOON SEABREEZE.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY
THROUGH TUESDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...SHOWER ACTIVITY GOT OFF TO AN EARLIER THAN
EXPECTED START...BUT THE REMAINDER OF THE FORECAST IS NEARLY
UNCHANGED. THE BULK OF THE SHOWERS SHOULD WRAP UP BY LATE MORNING AS
THE FOCUS FOR NEW CONVECTIVE DEVELOPMENT SHIFTS INLAND WITH THE
DEVELOPING SEABREEZE CIRCULATION. SEAS BUILT TO 3 FT RECENTLY AT
BOTH THE WILMINGTON HARBOR BUOY JUST SOUTH OF SOUTHPORT...AND AT THE
OCEAN CREST PIER WAVE GAUGE ON OAK ISLAND. I HAVE BUMPED UP THE
ONSET OF 3 FOOT SEAS BY A FEW HOURS TO MATCH OBSERVATIONS. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
HIGH PRESSURE OFF THE U.S. EAST COAST WILL MAINTAIN A
SOUTH-SOUTHWEST WIND ACROSS THE AREA TODAY AND TONIGHT. HIGH
RESOLUTION MODELS INDICATE A LANDBREEZE MAY DEVELOP ALONG THE SOUTH
CAROLINA COAST AROUND DAYBREAK...POTENTIALLY IGNITING SCATTERED
SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE MORNING HOURS. RADAR
IS CURRENTLY CLEAR...BUT THIS PATTERN OF AN EARLY MORNING LANDBREEZE
LEADING TO SHOWERS IS A TYPICAL AUGUST WEATHER SCENARIO HERE. AS
HEAT BUILDS INLAND DURING THE LATE MORNING AND AFTERNOON HOURS MOST
OF THE SHOWER ACTIVITY OVER THE OCEAN SHOULD DISSIPATE WITH A MODEST
SEABREEZE INCREASING WIND SPEEDS TO 15 KNOTS NEAR SHORE. FOR TONIGHT
SHOWER CHANCES APPEAR QUITE LOW AS SOUTH-SOUTHWEST WINDS RETURN TO A
STEADY 10-15 KNOTS.
SEAS CURRENTLY AVERAGE 2 FT NEARSHORE WITH 2.5 TO 3 FOOT SEAS
REPORTED FROM THE FRYING PAN SHOALS BUOY. SEAS SHOULD AVERAGE 2-3 FT
THROUGH TONIGHT IN A COMBINATION OF 4 SECOND WIND WAVE AND 9 SECOND
SOUTHEAST SWELL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A RELATIVELY WEAK FRONT OR SURFACE TROUGH WILL
REMAIN INLAND ALLOWING A PERSISTENT SOUTHWEST FLOW TO CONTINUE
THOUGH THE PERIOD. WIND SPEEDS WILL BE 10-15 KNOTS. IT APPEARS THERE
IS A LITTLE ENHANCEMENT OF THE LOW LEVEL WIND FIELDS OVERNIGHT
SATURDAY INTO SUNDAY MORNING WHICH WILL TILT THE SPEEDS TO THE
HIGHER END OF THE RANGE. SIGNIFICANT SEAS REMAIN UNCHANGED WITH 2-3
FEET SHORTER PERIOD WIND WAVES.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...DIFFUSE FRONT DRAPED ACROSS THE AREA WILL NOT
HAVE A SIGNIFICANT IMPACT ON THE COASTAL WATERS FORECAST AT LEAST
FROM A SYNOPTIC STANDPOINT. SOUTHWEST WINDS OF AROUND TEN KNOTS WILL
PREVAIL WITH SIGNIFICANT SEAS OF 2-4 FEET. THE WAVEWATCH GUIDANCE IS
TRENDING UP FROM 2-3 FEET MONDAY TO 2-4 FEET TUESDAY MAINLY ACROSS
THE OUTER WATERS. PERIODS SHOW WIND WAVES WHICH GIVES ME PAUSE AS
THE WIND FIELDS REMAIN WEAK BUT THE INCREASE ISN/T A SIGNIFICANT
IMPACT ON THE FORECAST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
318 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY GIVE WAY TO A MORE UNSETTLED PATTERN FOR
THE NEXT SEVERAL DAYS. GENEROUS AMOUNTS OF RAINFALL ARE POSSIBLE
SUNDAY THROUGH MUCH OF NEXT WEEK. A FRONT MAY MOVE FAR ENOUGH
SOUTH LATE NEXT WEEK LEADING TO DRIER CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...SURFACE HIGH PRESSURE OFF THE U.S. EAST COAST
IS DRAWING HOT TROPICAL AIR NORTHWARD FROM THE CARIBBEAN. THE
SUBTROPICAL RIDGE AT 500 THROUGH 200 MB IS NEARLY OVERHEAD AS A
WELL-DEFINED TUTT LOW MOVES WESTWARD UNDER THE RIDGE ACROSS THE
FLORIDA KEYS. 850 MB TEMPERATURES HAVE WARMED ALMOST ANOTHER FULL
DEGREE CELSIUS FROM YESTERDAY WHICH SHOULD GUARANTEE 91-93 ACROSS
MOST OF THE INTERIOR EASTERN CAROLINAS...WITH 88-90 EXPECTED NEAR
THE COAST. IT IS WORTH NOTING THAT THE MARINE ENVIRONMENT IS RIGHT
AT ITS PEAK CLIMATOLOGICAL TEMPERATURES OF THE YEAR AS MEASURED BY
SEA SURFACE AND AIR TEMPERATURE...SO THE COOLING EFFECT PROVIDED BY
THE SEABREEZE HAS REACHED ITS MINIMUM.
STEADY SOUTH-SOUTHWEST WINDS HAVE BEEN BLOWING ALONG THE COAST ALL
MORNING. AS A LANDBREEZE DEVELOPS BETWEEN GEORGETOWN AND SOUTHPORT
AND INTERCEPTS THIS WARM AND HUMID LOW-LEVEL AIRSTREAM...EXPECT A
LINE OF TOWERING CUMULUS AND EVENTUALLY SHOWERS DEVELOP AROUND OR
SHORTLY AFTER DAYBREAK. THE LAST SEVERAL RUNS OF THE HRRR DEPICT
THIS CONVECTION MAINLY REMAINING OFFSHORE...BUT IMPACTING AT LEAST
PORTIONS OF BRUNSWICK AND NEW HANOVER COUNTIES BETWEEN 8-11 AM. AS
HEAT AND HUMIDITY BUILD INLAND LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE SEABREEZE BOUNDARY
BEGINNING BY NOON. COVERAGE SHOULD AVERAGE ABOUT 30 PERCENT OF THE
AREA DURING THE DAYLIGHT HOURS...AIDED BY STORM MOTION TOWARD THE
NORTHEAST AT 12-15 MPH AND VERY LITTLE CONVECTIVE CAPPING WITHIN AN
AIRMASS CHARACTERIZED BY CAPE 1000-1500 J/KG. THESE SHOULD BE PULSE
STORMS WITH NO SIGNIFICANT WIND OR DRY LAYERS ALOFT AND PRECIPITABLE
WATER AROUND 2.0 INCHES.
CONVECTION SHOULD FALL APART DURING THE EARLY TO MID EVENING HOURS
WITH THE LOSS OF DAYTIME HEATING. MOSTLY CLEAR SKIES ARE EXPECTED
OVERNIGHT WITH LOWS FALLING TO 73-77...WARMEST ALONG THE SOUTH-
FACING BRUNSWICK COUNTY BEACHES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...MID LEVEL RIDGE WILL SLOWLY WEAKEN THROUGH THE PERIOD
AS THE TROPOSPHERE GRADUALLY BECOMES MORE CONDUCIVE FOR CONVECTION.
AT THE SURFACE...TOUGH TO DISTINGUISH BETWEEN AN ACTUAL FRONT OR
TROUGH BUT THE FOCUS WILL BE THE IMPORTANT FACTOR. NUMERICAL
GUIDANCE REFLECTS THIS TREND WITH SLOWLY INCREASING POPS FROM
SATURDAY MORNING THROUGH SUNDAY AFTERNOON. THE OFFICIAL FORECAST
SHOWS THIS AS WELL WITH POPS INITIALLY AT SLIGHT CHANCE TRENDING UP
TO GOOD CHANCE BY SUNDAY PM. PRECIPITABLE WATER VALUES CLIMB FROM
APPROXIMATELY 1.75 INCHES SATURDAY TO NEAR 2.00 INCHES SUNDAY.
SOME MINOR DISAGREEMENT BETWEEN THE MAV AND MET NUMBERS FOR HIGH
TEMPERATURES ESPECIALLY INLAND. WILL LEAN TOWARD THE WARMER MAV
NUMBERS SATURDAY AND SLIGHTLY COOLER MET NUMBERS SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT AN EXTENDED
PERIOD OF WET WEATHER AS TROUGHING IS IN PLACE ACROSS THE MIDWEST
AND RIDGING OUT WEST. THERE IS A SIGNAL THAT THE FRONT MAY SLIP FAR
ENOUGH SOUTH VIA THE PREFERRED ECMWF ENSEMBLE MEAN SOLUTION FROM WPC
THAT THURSDAY COULD DRY OUT A BIT. THIS IS REFLECTED IN GRAPHICS
FROM WPC AND IN OUR OFFICIAL FORECAST. WE ARE FORECASTING HIGH
CHANCE POPS AND EVEN A PERIOD...TUESDAY...OF LIKELY POPS WHICH SEEM
WARRANTED. AS MENTIONED LAST NIGHT...I BELIEVE THERE WILL BE MORE
LIKELY POPS WARRANTED AS WE DRAW CLOSER TO THE ONSET OF THE EVENT.
TEMPERATURE TRENDS REMAIN INTACT WITH DAYTIME HIGHS...CERTAINLY
MODULATED BY RAINFALL NEAR CLIMATOLOGY AND OVERNIGHT LOWS A BIT ON
THE HIGH SIDE CITING THE PREVAILING MOISTURE.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A SOUTHWEST LOW LEVEL JET WITH 1000 FT AGL WIND SPEEDS
NEAR 20 KNOTS SHOULD PREVENT FOG FORMATION THROUGH DAYBREAK...BUT
COULD ACTUALLY FAVOR LOW STRATUS DEVELOPMENT INLAND. GFS AND NAM MOS
BOTH SHOW THIS POTENTIAL AT FLO AND LBT...BUT AFTER LAST NIGHT`S
BUST WITH IFR CONDITIONS FORECAST BUT NEVER OCCURRING I AM NOT SO
CERTAIN. FOR NOW I WILL ONLY INCLUDE SCATTERED LOW CLOUDS IN THE
FORECAST...BUT BE AWARE THERE IS SOME POTENTIAL FOR AN HOUR OR TWO
OF IFR CEILINGS AT BOTH FLO AND LBT...MAINLY 10-12Z.
AFTER DAYBREAK...SCATTERED CUMULUS WITH BASES 2000-3000 FT AGL
SHOULD DEVELOP WITH MODERATE SOUTHWEST LOW LEVEL WINDS GUSTING AS
HIGH AS 20 KNOTS AT THE COAST. MUCH LIKE YESTERDAY SCATTERED SHOWERS
MAY DEVELOP FIRST IN THE WILMINGTON AREA...SPREADING INLAND WITH THE
AFTERNOON SEABREEZE.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY
THROUGH TUESDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...HIGH PRESSURE OFF THE U.S. EAST COAST WILL
MAINTAIN A SOUTH-SOUTHWEST WIND ACROSS THE AREA TODAY AND TONIGHT.
HIGH RESOLUTION MODELS INDICATE A LANDBREEZE MAY DEVELOP ALONG THE
SOUTH CAROLINA COAST AROUND DAYBREAK...POTENTIALLY IGNITING
SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE MORNING
HOURS. RADAR IS CURRENTLY CLEAR...BUT THIS PATTERN OF AN EARLY
MORNING LANDBREEZE LEADING TO SHOWERS IS A TYPICAL AUGUST WEATHER
SCENARIO HERE. AS HEAT BUILDS INLAND DURING THE LATE MORNING AND
AFTERNOON HOURS MOST OF THE SHOWER ACTIVITY OVER THE OCEAN SHOULD
DISSIPATE WITH A MODEST SEABREEZE INCREASING WIND SPEEDS TO 15
KNOTS NEAR SHORE. FOR TONIGHT SHOWER CHANCES APPEAR QUITE LOW AS
SOUTH-SOUTHWEST WINDS RETURN TO A STEADY 10-15 KNOTS.
SEAS CURRENTLY AVERAGE 2 FT NEARSHORE WITH 2.5 TO 3 FOOT SEAS
REPORTED FROM THE FRYING PAN SHOALS BUOY. SEAS SHOULD AVERAGE 2-3 FT
THROUGH TONIGHT IN A COMBINATION OF 4 SECOND WIND WAVE AND 9 SECOND
SOUTHEAST SWELL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A RELATIVELY WEAK FRONT OR SURFACE TROUGH WILL
REMAIN INLAND ALLOWING A PERSISTENT SOUTHWEST FLOW TO CONTINUE
THOUGH THE PERIOD. WIND SPEEDS WILL BE 10-15 KNOTS. IT APPEARS THERE
IS A LITTLE ENHANCEMENT OF THE LOW LEVEL WIND FIELDS OVERNIGHT
SATURDAY INTO SUNDAY MORNING WHICH WILL TILT THE SPEEDS TO THE
HIGHER END OF THE RANGE. SIGNIFICANT SEAS REMAIN UNCHANGED WITH 2-3
FEET SHORTER PERIOD WIND WAVES.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...DIFFUSE FRONT DRAPED ACROSS THE AREA WILL NOT
HAVE A SIGNIFICANT IMPACT ON THE COASTAL WATERS FORECAST AT LEAST
FROM A SYNOPTIC STANDPOINT. SOUTHWEST WINDS OF AROUND TEN KNOTS WILL
PREVAIL WITH SIGNIFICANT SEAS OF 2-4 FEET. THE WAVEWATCH GUIDANCE IS
TRENDING UP FROM 2-3 FEET MONDAY TO 2-4 FEET TUESDAY MAINLY ACROSS
THE OUTER WATERS. PERIODS SHOW WIND WAVES WHICH GIVES ME PAUSE AS
THE WIND FIELDS REMAIN WEAK BUT THE INCREASE ISN/T A SIGNIFICANT
IMPACT ON THE FORECAST.
&&
.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
310 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL KEEP A MOIST AIR MASS IN
PLACE OVER THE CAROLINAS TODAY. A COLD FRONT WILL MOVE INTO THE
REGION THIS WEEKEND... THEN STALL OVER THE AREA INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
THIS MORNING...
PATCHY CIRRUS IS MOSTLY DISSIPATING OVERHEAD...WITH PARTLY CLOUDY
SKIES OBSERVED OVER THE WESTERN CWA AND NEARLY CLEAR CONDITIONS OVER
THE EAST. A LIGHT SOUTHERLY WIND CONTINUES TO STIR OVER MUCH OF THE
CWA...BUT WHERE WINDS GO CALM...SOME PATCHY FOG MAY BE POSSIBLE
AROUND SUNRISE. THE HRRR ALSO SHOWS SOME SHOWERS DEVELOPING OVER
UPSTATE SC...DRIFTING NORTHEAST INTO THE WESTERN PIEDMONT. WHILE
SOME WEAK MUCAPE ANALYZED ON THE SPC MESO-ANALYSIS WOULD SUPPORT
THIS...THERE HAVE YET TO BE ANY SIGNS OF DEVELOPMENT ON REGIONAL
RADAR.
TODAY...
AS A COLD FRONT MOVES SLOWLY THROUGH THE OHIO VALLEY REGION
TODAY...THE DEEP LAYER FLOW AHEAD OF THE FRONT WILL BECOME MORE
UNIFORM AND SOUTHWESTERLY. THE UPPER LEVEL RIDGE TO OUR SOUTHWEST
WILL CAUSE A COUPLE CONVECTIVELY INDUCED DISTURBANCES UPSTREAM TO
SHEAR OUT AND DRIFT NORTHEAST TOWARD THE MID-ATLANTIC STATES TODAY.
THIS WILL LEAVE LOW-LEVEL CONVERGENCE IN THE FORM OF A
PREFRONTAL/LEE TROUGH AS THE MAIN TRIGGER FOR SCATTERED CONVECTION
THIS AFTERNOON. PW VALUES ARE RATHER HIGH...ABOVE 2 INCHES...BUT
MID-LEVEL LAPSE RATES ARE WEAK AND MLCAPE IS FORECAST TO REMAIN
AROUND 1000 J/KG AT BEST. MOST OF THE HI-RES MODELS SHOW
DEVELOPMENT GENERALLY FROM WINSTON-SALEM TO ROXBORO BY 20Z....WHERE
THE SFC TO 850MB CONVERGENCE IS STRONGEST....DRIFTING EAST THIS
EVENING BUT DYING OFF WITH LOSS OF HEATING. THE SEABREEZE SHOULD
ALSO BE ACTIVE AGAIN...THOUGH SOUTHWESTERLY LOW-LEVEL FLOW WOULD NOT
SUPPORT A STRONG INLAND PUSH.
REGARDING HIGHS...LOW-LEVEL THICKNESSES ARE FORECAST TO BE EQUAL TO
OR GREATER THAN OBSERVED VALUES ON THURSDAY...WHICH WOULD SUPPORT
LEANING TOWARD THE WARMER MAV MOS VALUES OF UPPER 80S AND LOWERS
90S. THIS IS ALSO BE SUPPORTED BY MORE WEST-SOUTHWESTERLY
PRE-FRONTAL FLOW WITH AT LEAST A WEAK DOWNSLOPE COMPONENT.
TONIGHT...
THE COLD FRONT WILL REMAIN TO OUR NORTH TONIGHT...AND INCREASINGLY
WESTERLY 850MB FLOW SHOULD HELP TO LIMIT ANY ADDITIONAL SHOWERS OR
STORMS OVERNIGHT. A CAVEAT TO THIS COULD BE OUTFLOW FROM STORMS TO
OUR NORTH...BUT HI-RES MODELS ARENT SHOWING VERY ROBUST CONVECTION
ALONG THE MAIN FRONTAL ZONE TODAY. THUS...EXPECT MOST OF THE NIGHT
TO BE DRY AFTER MIDNIGHT...WITH MUGGY LOWS IN THE LOWER 70S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...
SATURDAY AND SATURDAY NIGHT...
THE COLD FRONT TO OUR NORTH IS FORECAST TO SLIDE SOUTH INTO NC AND
ESSENTIALLY STALL THROUGH THE WEEKEND. WITH HIGH PW VALUES AROUND 2
INCHES...MORE FOCUSED LOW-LEVEL CONVERGENCE...AND SLIGHTLY STRONGER
BUT BROAD CYCLONIC FLOW ALOFT...SHOWERS AND STORMS SHOULD BE MORE
NUMEROUS BY EARLY SATURDAY AFTERNOON. SREF PROBABILITIES INDICATE A
MUCH GREATER LIKELIHOOD OF MLCAPE ABOVE 1000 J/KG...AND WITH 25-30KT
OF 0-6KM BULK SHEAR...A FEW CLUSTERS OF STRONG STORMS WITH DAMAGING
WIND GUSTS WILL BE POSSIBLE. A GREATER THREAT MAY BE TRAINING OF
HEAVY DOWNPOURS AS THE STEERING FLOW BECOMES PARALLEL TO THE FRONT.
WILL CONTINUE WITH LIKELY POPS DURING THE DAY SATURDAY AND MAINTAIN
A CHANCE ON SATURDAY NIGHT GIVEN THAT THE FRONT AND VARIOUS OUTFLOW
BOUNDARIES WILL LINGER OVER THE CWA. THICKER CLOUD COVER AND
EARLIER CONVECTIVE INITIATION MAY HOLD TEMPS DOWN TO THE MID/UPPER
80S IN THE NORTH SATURDAY...WHILE LOWER 90S MAY BE MORE COMMON
ACROSS THE SOUTHERN PIEDMONT/COASTAL PLAIN AS THE 850MB THERMAL
RIDGE SHIFT SOUTH. SATURDAY NIGHT LOWS AGAIN IN THE LOWER 70S.
-SMITH
FOR SUNDAY/SUNDAY NIGHT: WILL BE TOUGH TO ESCAPE GETTING WET ON
SUNDAY. THE DIFFUSE FRONTAL ZONE IS LIKELY TO BE SITUATED FROM SE VA
ACROSS NW NC AND BACK NW THROUGH KY... WITH A PRECEDING TROUGH
THROUGH ERN AND SOUTH CENTRAL NC (POTENTIALLY REINFORCED BY
CONVECTIVE OUTFLOW)... WHILE MID LEVEL LONGWAVE TROUGH AMPLIFIES
SLIGHTLY THROUGH SUNDAY NIGHT. DYNAMIC FORCING FOR ASCENT IS WEAK
BUT EVIDENT AT THE MID-UPPER LEVELS... INCLUDING UPPER DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF THE WEAKENING 80 KT WESTERLY JET TO OUR
NE... SUBTLE DPVA WITH ONE WEAK MIDLEVEL WAVE SKIRTING ACROSS VA/NRN
NC SUNDAY... AND 20-30 METER MIDLEVEL HEIGHT FALLS. BUT THE SOMEWHAT
WEAK AND LARGELY WESTERLY LOW LEVEL WIND FIELD SUGGESTS THAT LIFT
ROOTED IN THE LOWER LEVELS MAY BE LIMITED TO SURFACE CONVERGENCE
ALONG THE TROUGH. DEEP LAYER BULK SHEAR IS MARGINAL AT AROUND 20-25
KTS (HIGHEST NORTH) THROUGH MUCH OF SUNDAY/SUNDAY NIGHT... BUT WITH
MLCAPE PROJECTED TO PEAK AT 1200-2000 J/KG (LOWEST NW AND HIGHEST
SE) AND CAPE IN THE MIXED-PHASE REGION TOPPING OUT AT A FAIRLY
RESPECTABLE 500-900 J/KG... A FEW STORMS COULD BECOME STRONG WITH A
RISK OF HAIL. HEAVY RAINERS AND TRAINING/SLOW-MOVING CELLS WILL ALSO
BRING ABOUT A RISK OF LOCALIZED FLOODING GIVEN PW VALUES HOLDING
AROUND 2 INCHES... AND THE WESTERLY FLOW AND HINTS AT AN INVERTED-V
PROFILE INDICATE POSSIBLE STRONG WIND GUSTS AS WELL. BELIEVE WE`LL
SEE GOOD COVERAGE OF CONVECTION EARLY ACROSS THE NORTH... RISING TO
LIKELY AND TRANSLATING SLOWLY TO THE SOUTHEAST THROUGH THE AFTERNOON
AND EVENING... BEFORE TRENDING OUT OF ALL BUT THE FAR EASTERN CWA
OVERNIGHT. HIGHS 86-91 AND LOWS 68-73.
FOR MONDAY/MONDAY NIGHT: THE SURFACE FRONT IS LIKELY TO BECOME EVEN
WEAKER AND MORE DIFFUSE OVER THE REGION MONDAY... AS IT WAITS FOR A
SECOND STRONGER COLD FRONT (ASSOCIATED WITH THE MID LEVEL SHORTWAVE
TROUGH SWINGING THROUGH SRN ONTARIO/SW QUEBEC) TO PUSH SOUTHEASTWARD
THROUGH THE GREAT LAKES/OH VALLEY TOWARD NC. WE MAY SEE ANOTHER
EARLY START TO CONVECTION ALONG THE DYING TROUGH OVER THE
CAROLINAS... AS THE GFS DEPICTS 18Z MLCAPE OF 2000-2500 J/KG AND
-10C TO -30C CAPE REACHING 1000 J/KG AREAWIDE. WHILE DYNAMIC FORCING
FOR LIFT LOOKS EVEN WEAKER MONDAY THAN ON SUNDAY... THE HIGH PW
VALUES ALONG WITH FAVORABLE THERMODYNAMICS AND THE PRESENCE OF A LOW
LEVEL FOCUS SUGGEST WE SHOULD SEE AT LEAST 50-60% COVERAGE OF
SHOWERS/STORMS IN THE AFTERNOON... PARTICULARLY OVER THE CENTRAL AND
SE PORTIONS OF THE FORECAST AREA... WINDING DOWN AS WE HEAD THROUGH
THE EVENING WITH LOSS OF HEATING AND SUBSEQUENT STABILIZATION.
MODELS DIFFER WIDELY ON THICKNESSES... LIKELY DUE IN PART TO
DIFFERENCES IN CLOUD COVER AND PRECIP COVERAGE... BUT GIVEN
EXPECTATIONS OF DECENT MID LEVEL CLOUD COVER THROUGH THIS TIME FRAME
AND POSSIBLE EARLY CONVECTION... WILL HOLD HIGH TEMPS A BIT BELOW
NORMAL... 85-89... WITH NEAR NORMAL LOWS OF 69-73. -GIH
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 310 AM FRIDAY...
EXPECT CONTINUED ABOVE-NORMAL RAIN CHANCES INTO WEDNESDAY...
FOLLOWED BY DRIER AND COOLER (POTENTIALLY MUCH SO) CONDITIONS FOR
THURSDAY. MODELS DIG THE MIDLEVEL TROUGH DOWN WELL INTO THE EASTERN
CONUS TUESDAY INTO WEDNESDAY... WITH THE SURFACE COLD FRONT PUSHING
TO OUR SOUTH WEDNESDAY. THEY THEN DEPICT THE DEVELOPMENT OF COLD AIR
DAMMING LATE WEDNESDAY AS THE SURFACE FRONT PUSHES JUST TO OUR
SOUTH WHILE CANADIAN HIGH PRESSURE SLIDES BY TO OUR NORTH... ACROSS
THE GREAT LAKES/OH VALLEY TO THE MIDATLANTIC/NORTHEAST. THE
AGREEMENT AMONG THE GFS/ECMWF/CANADIAN REGARDING THIS EVOLUTION IS
ACTUALLY FAIRLY GOOD CONSIDERING IT IS DAYS 5-7 OF THE FORECAST.
WILL KEEP A GOOD CHANCE OF SHOWERS/STORMS (HIGHER SOUTH/EAST)
TUESDAY INTO WEDNESDAY WITH TEMPS TRENDING FROM NEAR NORMAL TO JUST
BELOW NORMAL... THEN WILL GO LARGELY DRY THURSDAY BUT WITH LINGERING
CLOUD COVER AS 850 MB OVERRUNNING FLOW SHOULD RESUME BY LATE IN THE
DAY. GFS/ECMWF THICKNESSES PLUNGE TO AROUND 30 METERS BELOW NORMAL
THURSDAY... SUGGESTING HIGHS OF 77-83. -GIH
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
MOSTLY VFR CONDITIONS ACROSS CENTRAL NC EARLY THIS MORNING. SOME OF
THE HIGH RESOLUTION MODELS ARE SHOWING THE DEVELOPMENT OF SHOWERS
OVER UPSTATE SC THROUGH 09Z...WHICH WOULD THEN DRIFT NORTHEAST INTO
THE WESTERN PIEDMONT OF NC. HOWEVER...THERE HAVE YET TO BE ANY
SIGNS OF SHOWER ACTIVITY...SO THE MAIN CONCERN FOR KGSO AND KINT
WILL BE STRATUS JUST PRIOR TO SUNRISE. GIVEN THAT THE PATTERN HAS
NOT CHANGED VERY MUCH OVER THE PAST 24 HOURS AND THERE WAS VERY
LITTLE STRATUS THURSDAY MORNING...THE CURRENT THINKING IS THAT ANY
IFR/MVFR CEILINGS WILL BE VERY BRIEF BETWEEN 10Z AND 13Z. TO THE
EAST...WHERE SKIES ARE ESSENTIALLY CLEAR AT THE MOMENT...IFR AND
MVFR VSBYS ARE MORE LIKELY IF WINDS GO CALM. AGAIN...THIS APPEARS
TO BE A THREAT TO OCCUR AROUND SUNRISE...WITH VFR CONDITIONS TO
PREVAIL BY 15Z. SCATTERED SHOWERS AND STORMS SHOULD DEVELOP THIS
AFTERNOON...MOSTLY LIKELY IMPACTING KGSO AND KINT AFTER 20Z.
OUTLOOK...
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH/BSD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL KEEP A MOIST AIR MASS IN
PLACE OVER THE CAROLINAS TODAY. A COLD FRONT WILL MOVE INTO THE
REGION THIS WEEKEND... THEN STALL OVER THE AREA INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
THIS MORNING...
PATCHY CIRRUS IS MOSTLY DISSIPATING OVERHEAD...WITH PARTLY CLOUDY
SKIES OBSERVED OVER THE WESTERN CWA AND NEARLY CLEAR CONDITIONS OVER
THE EAST. A LIGHT SOUTHERLY WIND CONTINUES TO STIR OVER MUCH OF THE
CWA...BUT WHERE WINDS GO CALM...SOME PATCHY FOG MAY BE POSSIBLE
AROUND SUNRISE. THE HRRR ALSO SHOWS SOME SHOWERS DEVELOPING OVER
UPSTATE SC...DRIFTING NORTHEAST INTO THE WESTERN PIEDMONT. WHILE
SOME WEAK MUCAPE ANALYZED ON THE SPC MESO-ANALYSIS WOULD SUPPORT
THIS...THERE HAVE YET TO BE ANY SIGNS OF DEVELOPMENT ON REGIONAL
RADAR.
TODAY...
AS A COLD FRONT MOVES SLOWLY THROUGH THE OHIO VALLEY REGION
TODAY...THE DEEP LAYER FLOW AHEAD OF THE FRONT WILL BECOME MORE
UNIFORM AND SOUTHWESTERLY. THE UPPER LEVEL RIDGE TO OUR SOUTHWEST
WILL CAUSE A COUPLE CONVECTIVELY INDUCED DISTURBANCES UPSTREAM TO
SHEAR OUT AND DRIFT NORTHEAST TOWARD THE MID-ATLANTIC STATES TODAY.
THIS WILL LEAVE LOW-LEVEL CONVERGENCE IN THE FORM OF A
PREFRONTAL/LEE TROUGH AS THE MAIN TRIGGER FOR SCATTERED CONVECTION
THIS AFTERNOON. PW VALUES ARE RATHER HIGH...ABOVE 2 INCHES...BUT
MID-LEVEL LAPSE RATES ARE WEAK AND MLCAPE IS FORECAST TO REMAIN
AROUND 1000 J/KG AT BEST. MOST OF THE HI-RES MODELS SHOW
DEVELOPMENT GENERALLY FROM WINSTON-SALEM TO ROXBORO BY 20Z....WHERE
THE SFC TO 850MB CONVERGENCE IS STRONGEST....DRIFTING EAST THIS
EVENING BUT DYING OFF WITH LOSS OF HEATING. THE SEABREEZE SHOULD
ALSO BE ACTIVE AGAIN...THOUGH SOUTHWESTERLY LOW-LEVEL FLOW WOULD NOT
SUPPORT A STRONG INLAND PUSH.
REGARDING HIGHS...LOW-LEVEL THICKNESSES ARE FORECAST TO BE EQUAL TO
OR GREATER THAN OBSERVED VALUES ON THURSDAY...WHICH WOULD SUPPORT
LEANING TOWARD THE WARMER MAV MOS VALUES OF UPPER 80S AND LOWERS
90S. THIS IS ALSO BE SUPPORTED BY MORE WEST-SOUTHWESTERLY
PRE-FRONTAL FLOW WITH AT LEAST A WEAK DOWNSLOPE COMPONENT.
TONIGHT...
THE COLD FRONT WILL REMAIN TO OUR NORTH TONIGHT...AND INCREASINGLY
WESTERLY 850MB FLOW SHOULD HELP TO LIMIT ANY ADDITIONAL SHOWERS OR
STORMS OVERNIGHT. A CAVEAT TO THIS COULD BE OUTFLOW FROM STORMS TO
OUR NORTH...BUT HI-RES MODELS ARENT SHOWING VERY ROBUST CONVECTION
ALONG THE MAIN FRONTAL ZONE TODAY. THUS...EXPECT MOST OF THE NIGHT
TO BE DRY AFTER MIDNIGHT...WITH MUGGY LOWS IN THE LOWER 70S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...
SATURDAY AND SATURDAY NIGHT...
THE COLD FRONT TO OUR NORTH IS FORECAST TO SLIDE SOUTH INTO NC AND
ESSENTIALLY STALL THROUGH THE WEEKEND. WITH HIGH PW VALUES AROUND 2
INCHES...MORE FOCUSED LOW-LEVEL CONVERGENCE...AND SLIGHTLY STRONGER
BUT BROAD CYCLONIC FLOW ALOFT...SHOWERS AND STORMS SHOULD BE MORE
NUMEROUS BY EARLY SATURDAY AFTERNOON. SREF PROBABILITIES INDICATE A
MUCH GREATER LIKELIHOOD OF MLCAPE ABOVE 1000 J/KG...AND WITH 25-30KT
OF 0-6KM BULK SHEAR...A FEW CLUSTERS OF STRONG STORMS WITH DAMAGING
WIND GUSTS WILL BE POSSIBLE. A GREATER THREAT MAY BE TRAINING OF
HEAVY DOWNPOURS AS THE STEERING FLOW BECOMES PARALLEL TO THE FRONT.
WILL CONTINUE WITH LIKELY POPS DURING THE DAY SATURDAY AND MAINTAIN
A CHANCE ON SATURDAY NIGHT GIVEN THAT THE FRONT AND VARIOUS OUTFLOW
BOUNDARIES WILL LINGER OVER THE CWA. THICKER CLOUD COVER AND
EARLIER CONVECTIVE INITIATION MAY HOLD TEMPS DOWN TO THE MID/UPPER
80S IN THE NORTH SATURDAY...WHILE LOWER 90S MAY BE MORE COMMON
ACROSS
THE SOUTHERN PIEDMONT/COASTAL PLAIN AS THE 850MB THERMAL RIDGE SHIFT
SOUTH. SATURDAY NIGHT LOWS AGAIN IN THE LOWER 70S. -SMITH
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...
UPDATED SHORTLY...
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
MOSTLY VFR CONDITIONS ACROSS CENTRAL NC EARLY THIS MORNING. SOME OF
THE HIGH RESOLUTION MODELS ARE SHOWING THE DEVELOPMENT OF SHOWERS
OVER UPSTATE SC THROUGH 09Z...WHICH WOULD THEN DRIFT NORTHEAST INTO
THE WESTERN PIEDMONT OF NC. HOWEVER...THERE HAVE YET TO BE ANY
SIGNS OF SHOWER ACTIVITY...SO THE MAIN CONCERN FOR KGSO AND KINT
WILL BE STRATUS JUST PRIOR TO SUNRISE. GIVEN THAT THE PATTERN HAS
NOT CHANGED VERY MUCH OVER THE PAST 24 HOURS AND THERE WAS VERY
LITTLE STRATUS THURSDAY MORNING...THE CURRENT THINKING IS THAT ANY
IFR/MVFR CEILINGS WILL BE VERY BRIEF BETWEEN 10Z AND 13Z. TO THE
EAST...WHERE SKIES ARE ESSENTIALLY CLEAR AT THE MOMENT...IFR AND
MVFR VSBYS ARE MORE LIKELY IF WINDS GO CALM. AGAIN...THIS APPEARS
TO BE A THREAT TO OCCUR AROUND SUNRISE...WITH VFR CONDITIONS TO
PREVAIL BY 15Z. SCATTERED SHOWERS AND STORMS SHOULD DEVELOP THIS
AFTERNOON...MOSTLY LIKELY IMPACTING KGSO AND KINT AFTER 20Z.
OUTLOOK...
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH
LONG TERM...MLM/BAS
AVIATION...SMITH/BSD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1015 PM CDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 1015 PM CDT SAT AUG 10 2013
STRONG THUNDERSTORMS HAVE EXITED SOUTHWESTERN NORTH DAKOTA.
AN AREA OF SHOWERS WITH ISOLATED THUNDERSTORMS WILL CONTINUE TO
MOVE SOUTH ACROSS SOUTHWESTERN AND SOUTHCENTRAL NORTH DAKOTA
THROUGH THE OVERNIGHT HOURS. THIS SHOULD PRODUCE AN ADDITIONAL ONE
TENTH TO ONE QUARTER INCH OF PRECIPITATION OVER THE AFFECTED AREAS.
THE ONLY UPDATE TO THE FORECAST WAS TO REMOVE FIRST PERIOD POPS
FROM THE EASTERN ZONES AS DRIER AIR FILTERS IN FROM THE NORTH. THE
REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED GRIDDED
AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 715 PM CDT SAT AUG 10 2013
NUMEROUS THUNDERSTORMS WEST OF THE MISSOURI RIVER HAVE LOST
THEIR SEVERE CHARACTERISTICS WITHIN THE PAST HOUR WITH THE LOSS OF
DAYTIME HEATING. THUNDERSTORMS COULD BE STRONG AT TIMES DURING THE
NEXT HOUR OR SO. HOWEVER...A CONTINUED DOWNWARD TREND IN INTENSITY
IS EXPECTED TO CONTINUE WITH DECREASING CAPE.
THE 22Z HRRR PROGS THIS AREA OF CONVECTION TO CONTINUE TO PUSH
SOUTH ACROSS SOUTHWESTERN AND SOUTHCENTRAL NORTH DAKOTA THIS
EVENING. IT SHOULD CONTINUE WEAKEN AND MOVE OUT OF THE BISMARCK
CWA BY 09Z. UPDATED HOURLY POPS BASED ON THE LATEST RUN OF THE HRRR.
FURTHERMORE...HEAVY RAINFALL REPORTS OF ONE TO THREE INCHES IN SPOTS
WILL ADD TO RESIDUAL LOW LEVEL MOISTURE OVER WESTERN NORTH DAKOTA.
THE LATEST SHORT RANGE MODEL GUIDANCE PROGS THE CENTER OF A
SURFACE ANTICYCLONE TO SETTLE OVER NORTHWESTERN NORTH DAKOTA BY
EARLY SUNDAY MORNING. THE COMBINATION OF LIGHT WINDS AND RESIDUAL
LOW-LEVEL MOISTURE SHOULD ALLOW FOR AREAS OF FOG TO DEVELOP OVER
NORTHWESTERN NORTH DAKOTA...WITH PATCHY FOG POSSIBLE OVER
SOUTHWESTERN NORTH DAKOTA. UPDATED THE FORECAST TO REFLECT THIS
LINE OF REASONING.
THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
THE MAIN FORECAST CONCERN IN THE SHORT TERM PERIOD IS CONVECTIVE
TRENDS AND MARGINAL SEVERE POTENTIAL THROUGH TONIGHT. LATEST HI-
RES WRF/HRRR MODEL RUNS POINT TO POTENTIAL FOR STRONG STORMS
CONTINUING TO SPREAD INTO THE WEST THIS AFTERNOON/EVENING...SUPPORTED
BY A DECENT SHORT WAVE TROUGH CURRENTLY IN SOUTHERN
SASKATCHEWAN...AND ANOTHER IMPULSE IN CENTRAL MONTANA. MUCAPES AOA
1000 J/KG AND MARGINAL DEEP LAYER SHEAR SUGGEST AN ISOLATED STORM
OR TWO CAPABLE OF QUARTER SIZE HAIL. INVERTED V BUFR SOUNDINGS
ALSO INDICATE SOME GUSTY WIND POTENTIAL WITH STORM DOWNDRAFTS. STORMS
IN FAR NORTHEAST MONTANA HAVE ALREADY PRODUCED SOME HAIL UP TO
PENNY SIZE IN ROOSEVELT COUNTY. ALSO THINKING THE SHORTWAVE WILL
SUSTAIN SHOWERS AND STORMS INTO CENTRAL AND SOUTHEAST COUNTIES
AFTER DARK. LOOKING AHEAD...ISOLATED STORMS WILL AGAIN BE POSSIBLE
SUNDAY AFTERNOON IN THE EXTREME SOUTHWEST WITH THE ARRIVAL OF
ANOTHER PIECE OF MID-LEVEL ENERGY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
MAIN FORECAST CONCERNS ARE INTERMITTENT PRECIP CHANCES THROUGH
THE PERIOD. GFS/ECMWF/GEM/ENSEMBLES ARE ALL IN GOOD AGREEMENT WITH
OVERALL PATTERN THROUGH THE EXTENDED. UPPER LEVEL PATTERN WILL
CONSIST OF WESTERN N AMERICAN RIDGE IN PLACE WITH EASTERN N
AMERICAN TROUGH. THIS PLACES THE NORTHERN PLAINS IN NORTHWEST FLOW
WITH OCCASIONAL DISTURBANCES MOVING ACROSS THE REGION...SUPPORTING
INTERMITTENT CHANCES OF PRECIPITATION. BEST CHANCES FOR PRECIP
WILL BE ACROSS SOUTHWEST PORTION OF THE STATE...CLOSER TO BEST
INSTABILITY. 00Z ECMWF SHOWS A BETTER DEFINED SHORTWAVE IN
NORTHWEST FLOW ON THURSDAY. FOR NOW...WILL CONTINUE TO CARRY SMALL
POCKET OF CHANCE POPS ASSOCIATED WITH THIS FEATURE INTO CENTRAL
NORTH DAKOTA THURSDAY...BUT OTHERWISE ANY PRECIP CHANCES REMAIN
RELATIVELY LOW IN THE SLIGHT CHANCE CATEGORY.
WITH REGARD TO TEMPERATURES...MAX TEMPS EARLY IN THE PERIOD SHOULD
START OUT SLIGHTLY BELOW NORMAL. NORMAL HIGH FOR BIS IS 85 FOR THE
NEXT SEVERAL DAYS. AS RIDGE AXIS OVER THE WEST NUDGES EASTWARD
SLIGHTLY...WE SHOULD SEE TEMPS BACK TO THE LOW 80S BY MID WEEK.
SLIGHT DIFFERENCES IN MODEL SOLUTIONS BY NEXT SATURDAY BUT
GFS/ECMWF/ENSEMBLES SUPPORT RIDGE AXIS OVER OR JUST TO THE WEST OF
ND WHICH WOULD SUPPORT ABOVE NORMAL TEMPS. 12Z MOS GUIDANCE GIVES
BIS A HIGH OF 92 NEXT SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 715 PM CDT SAT AUG 10 2013
THUNDERSTORMS AND ASSOCIATED MVFR CONDITIONS WILL IMPACT THE KDIK-
KBIS TERMINAL AERODROMES THIS EVENING. FURTHERMORE...MVFR VSBYS
COULD DEVELOP FROM KISN-KDIK BETWEEN 09Z-14Z. HOWEVER...CONFIDENCE
IS LOW IN THIS PANNING OUT SO WILL LEAVE OUT OF THE RESPECTIVE
TAFS FOR NOW. OTHERWISE...VFR CONDITIONS CAN BE EXPECTED OVER MOST
OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
LONG TERM...JNS
AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
715 PM CDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 715 PM CDT SAT AUG 10 2013
NUMEROUS THUNDERSTORMS WEST OF THE MISSOURI RIVER HAVE LOST
THEIR SEVERE CHARACTERISTICS WITHIN THE PAST HOUR WITH THE LOSS OF
DAYTIME HEATING. THUNDERSTORMS COULD BE STRONG AT TIMES DURING THE
NEXT HOUR OR SO. HOWEVER...A CONTINUED DOWNWARD TREND IN INTENSITY
IS EXPECTED TO CONTINUE WITH DECREASING CAPE.
THE 22Z HRRR PROGS THIS AREA OF CONVECTION TO CONTINUE TO PUSH
SOUTH ACROSS SOUTHWESTERN AND SOUTHCENTRAL NORTH DAKOTA THIS
EVENING. IT SHOULD CONTINUE WEAKEN AND MOVE OUT OF THE BISMARCK
CWA BY 09Z. UPDATED HOURLY POPS BASED ON THE LATEST RUN OF THE HRRR.
FURTHERMORE...HEAVY RAINFALL REPORTS OF ONE TO THREE INCHES IN SPOTS
WILL ADD TO RESIDUAL LOW LEVEL MOISTURE OVER WESTERN NORTH DAKOTA.
THE LATEST SHORT RANGE MODEL GUIDANCE PROGS THE CENTER OF A
SURFACE ANTICYCLONE TO SETTLE OVER NORTHWESTERN NORTH DAKOTA BY
EARLY SUNDAY MORNING. THE COMBINATION OF LIGHT WINDS AND RESIDUAL
LOW-LEVEL MOISTURE SHOULD ALLOW FOR AREAS OF FOG TO DEVELOP OVER
NORTHWESTERN NORTH DAKOTA...WITH PATCHY FOG POSSIBLE OVER
SOUTHWESTERN NORTH DAKOTA. UPDATED THE FORECAST TO REFLECT THIS
LINE OF REASONING.
THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
THE MAIN FORECAST CONCERN IN THE SHORT TERM PERIOD IS CONVECTIVE
TRENDS AND MARGINAL SEVERE POTENTIAL THROUGH TONIGHT. LATEST HI-
RES WRF/HRRR MODEL RUNS POINT TO POTENTIAL FOR STRONG STORMS
CONTINUING TO SPREAD INTO THE WEST THIS AFTERNOON/EVENING...SUPPORTED
BY A DECENT SHORT WAVE TROUGH CURRENTLY IN SOUTHERN
SASKATCHEWAN...AND ANOTHER IMPULSE IN CENTRAL MONTANA. MUCAPES AOA
1000 J/KG AND MARGINAL DEEP LAYER SHEAR SUGGEST AN ISOLATED STORM
OR TWO CAPABLE OF QUARTER SIZE HAIL. INVERTED V BUFR SOUNDINGS
ALSO INDICATE SOME GUSTY WIND POTENTIAL WITH STORM DOWNDRAFTS. STORMS
IN FAR NORTHEAST MONTANA HAVE ALREADY PRODUCED SOME HAIL UP TO
PENNY SIZE IN ROOSEVELT COUNTY. ALSO THINKING THE SHORTWAVE WILL
SUSTAIN SHOWERS AND STORMS INTO CENTRAL AND SOUTHEAST COUNTIES
AFTER DARK. LOOKING AHEAD...ISOLATED STORMS WILL AGAIN BE POSSIBLE
SUNDAY AFTERNOON IN THE EXTREME SOUTHWEST WITH THE ARRIVAL OF
ANOTHER PIECE OF MID-LEVEL ENERGY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
MAIN FORECAST CONCERNS ARE INTERMITTENT PRECIP CHANCES THROUGH
THE PERIOD. GFS/ECMWF/GEM/ENSEMBLES ARE ALL IN GOOD AGREEMENT WITH
OVERALL PATTERN THROUGH THE EXTENDED. UPPER LEVEL PATTERN WILL
CONSIST OF WESTERN N AMERICAN RIDGE IN PLACE WITH EASTERN N
AMERICAN TROUGH. THIS PLACES THE NORTHERN PLAINS IN NORTHWEST FLOW
WITH OCCASIONAL DISTURBANCES MOVING ACROSS THE REGION...SUPPORTING
INTERMITTENT CHANCES OF PRECIPITATION. BEST CHANCES FOR PRECIP
WILL BE ACROSS SOUTHWEST PORTION OF THE STATE...CLOSER TO BEST
INSTABILITY. 00Z ECMWF SHOWS A BETTER DEFINED SHORTWAVE IN
NORTHWEST FLOW ON THURSDAY. FOR NOW...WILL CONTINUE TO CARRY SMALL
POCKET OF CHANCE POPS ASSOCIATED WITH THIS FEATURE INTO CENTRAL
NORTH DAKOTA THURSDAY...BUT OTHERWISE ANY PRECIP CHANCES REMAIN
RELATIVELY LOW IN THE SLIGHT CHANCE CATEGORY.
WITH REGARD TO TEMPERATURES...MAX TEMPS EARLY IN THE PERIOD SHOULD
START OUT SLIGHTLY BELOW NORMAL. NORMAL HIGH FOR BIS IS 85 FOR THE
NEXT SEVERAL DAYS. AS RIDGE AXIS OVER THE WEST NUDGES EASTWARD
SLIGHTLY...WE SHOULD SEE TEMPS BACK TO THE LOW 80S BY MID WEEK.
SLIGHT DIFFERENCES IN MODEL SOLUTIONS BY NEXT SATURDAY BUT
GFS/ECMWF/ENSEMBLES SUPPORT RIDGE AXIS OVER OR JUST TO THE WEST OF
ND WHICH WOULD SUPPORT ABOVE NORMAL TEMPS. 12Z MOS GUIDANCE GIVES
BIS A HIGH OF 92 NEXT SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 715 PM CDT SAT AUG 10 2013
THUNDERSTORMS AND ASSOCIATED MVFR CONDITIONS WILL IMPACT THE KDIK-
KBIS TERMINAL AERODROMES THIS EVENING. FURTHERMORE...MVFR VSBYS
COULD DEVELOP FROM KISN-KDIK BETWEEN 09Z-14Z. HOWEVER...CONFIDENCE
IS LOW IN THIS PANNING OUT SO WILL LEAVE OUT OF THE RESPECTIVE
TAFS FOR NOW. OTHERWISE...VFR CONDITIONS CAN BE EXPECTED OVER MOST
OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
LONG TERM...JNS
AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
541 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 541 PM CDT FRI AUG 9 2013
THE LATEST WATER VAPOR IMAGERY SHOWS NORTHERN/CENTRAL NORTH DAKOTA
DOMINATED BY NORTHWEST FLOW ALOFT...WHILE FAR SOUTHWEST/SOUTHERN
NORTH DAKOTA ARE BECOMING DETACHED FROM THE DOMINATE NORTHWEST FLOW.
HERE...WEAK RIDGING WAS OBSERVED ON WATER VAPOR WHICH EXTENDED FROM
THE FRONT RANGE OF THE ROCKIES INTO THE PANHANDLE OF IDAHO. THIS IS
INDUCING A WEST TO WEAK NORTHWEST FLOW. COUPLE OF SHORTWAVES TO NOTE
FOR TONIGHT/SATURDAY...THE FIRST WAS ALONG THE NORTHERN WYOMING AND
MONTANA BORDER...A SECOND IN CENTRAL IDAHO...AND A THIRD IN EAST
CENTRAL ALBERTA. THESE SHORTWAVES WILL TOP THE RIDGE AND SHIFT EAST
TONIGHT/SATURDAY. THE STRONGEST OMEGA/LIFT FOR TONIGHT AND SATURDAY
REMAINS IN SOUTH DAKOTA...BUT DOES GRAZE WESTERN AND SOUTHERN NORTH
DAKOTA LATER TONIGHT THROUGH SATURDAY. THE LATEST HRRR REFLECTIVITY
SUGGESTS THAT CONVECTION NOW OVER SOUTH CENTRAL MONTANA WILL SHIFT
EAST TONIGHT ALLOWING FOR THE POSSIBILITY OF ISOLATED SHOWERS IN
THE FAR SOUTHWEST AND EDGING FAIRLY CLOSE TO OUR FAR SOUTH CENTRAL
ZONES...MAINLY TOWARD AND AFTER 05Z SATURDAY. WILL CONTINUE TO
WATCH THIS ACTIVITY THIS EVENING. LATEST BOWMAN RADAR IS JUST
BEGINNING TO SHOW SOME WEAK REFLECTIVITY`S IN FAR SOUTHEAST
MONTANA. FOR THIS UPDATE...HAVE INCREASED SKY GRIDS FOR THE EARLY
PART OF THIS EVENING BASED ON VISIBLE SATELLITE AND SURFACE
OBSERVATIONS. REST OF THE FORECAST HAS THE TRENDS HANDLED WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE MAIN FORECAST ISSUE IN THE NEAR TERM IS PRECIPITATION CHANCES
TONIGHT AND SATURDAY. A WARM FRONT WILL LIFT NORTH INTO SOUTH
DAKOTA TONIGHT AS A SHORT WAVE TROUGH TOPS THE UPPER RIDGE. RAIN
COVERAGE IS EXPECTED TO REMAIN RATHER LIMITED ACROSS THE SOUTHERN
COUNTIES SO 20/30 POPS SEEM REASONABLE. SHOWERS AND ISOLATED
STORMS WILL LIKELY PUSH A BIT FARTHER NORTH INTO THE STATE ON
SATURDAY AFTERNOON. THERE SHOULD BE ENOUGH ELEVATED INSTABILITY TO
SUPPORT A FEW THUNDERSTORMS...BUT NO SEVERE WEATHER IS ANTICIPATED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE EXTENDED WILL BE CHARACTERIZED BY A MID/UPPER LEVEL RIDGE SLOWLY
BUILDING FROM THE ROCKIES EARLY IN THE PERIOD INTO THE CENTRAL
PLAINS BY THE END OF THE PERIOD. THIS WILL GENERATE A GRADUAL
WARMING TREND TO NEAR NORMAL TEMPERATURES BY FRIDAY.
LINGERING CONVECTION ALONG AND SOUTH OF I-94 SATURDAY EVENING SHOULD
WANE WITH THE LOSS OF DAYTIME HEATING.
AS A MID/UPPER RIDGE BUILDS INTO THE REGION...UPPER LEVEL DYNAMICS
WILL BE ON THE DECREASE. HOWEVER...LINGERING MOISTURE AND
INSTABILITY WILL GENERATE A SLIGHT CHANCE OF DIURNALLY DRIVEN
CONVECTION PRIMARILY ALONG AND WEST OF THE MISSOURI RIVER DURING THE
AFTERNOON/EVENING HOURS SUNDAY THROUGH WEDNESDAY.
THE UPPER RIDGE IS PROGGED TO BREAK DOWN SOMEWHAT THURSDAY AS A
RIDGE RUNNER CRESTS OVER THE ANTICYCLONIC RIDGE AXIS. FOR NOW
INDICATED SLIGHT CHANCE POPS AREAWIDE. HOWEVER...POPS MAY NEED TO BE
INCREASED IF FUTURE RUNS ADD CREDENCE TO THE 12Z SUITE OF MODEL
GUIDANCE.
THE RIDGE RUNNER SHORTWAVE IS THEN PROGGED TO PUSH EAST OF THE REGION
FRIDAY WITH PRECIP CHANCES ENDING FROM WEST TO EAST. HIGHS FRIDAY
LOOK TO RANGE FROM THE LOWER 80S EAST TO THE UPPER 80S WEST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 541 PM CDT FRI AUG 9 2013
KMOT AND KJMS WILL BEGIN WITH LOW VFR CIGS AT 00Z SATURDAY WITH
IMPROVEMENTS TO SCT VFR BY AROUND 03Z. OVERALL SCT/BKN LOW TO MID
LEVEL CLOUDS WILL DOMINATE THROUGH SATURDAY...WITH A VCSH IN
KDIK/KBIS/KJMS UNTIL THE PRECIPITATION AREA BECOMES BETTER APPARENT
FOR PREDOMINANT CONDITIONS. KISN/KMOT LOOK TO BE FAR ENOUGH REMOVED
FROM ANY MENTION OF PRECIPITATION NEXT 24HR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...RP KINNEY
LONG TERM...TM
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1230 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1230 PM CDT FRI AUG 9 2013
SKY COVER WAS INCREASED A BIT FARTHER SOUTH TO ACCOUNT FOR DIURNAL
CUMULUS DEVELOPMENT. THICKER STRATOCU CLOSER TO THE CANADIAN
BORDER HAS LIMITED THE TEMPERATURE RISE...SO HAVE LOWERED HIGHS BY
A FEW DEGREES FOR THIS AFTERNOON FROM THE DEVILS LAKE BASIN INTO
THE NORTHERN VALLEY. HAVE KEPT THE ISOLATED SHOWER MENTION ALONG
THE CANADIAN BORDER FOR THIS AFTERNOON. THE 16Z RAP SHOWS LITTLE
IN THE WAY OF SHOWER ACTIVITY...BUT STILL SEEING SOME WEAK
UPSTREAM RETURNS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1230 PM CDT FRI AUG 9 2013
AREA OF MVFR TO LOW VFR CIGS CONTINUES TO PUSH SOUTHWARD FROM
MANITOBA BORDER THROUGH THE NORTHERN HALF OF THE FA DOWN TO THE US
HWY 2 CORRIDOR. EXPECT DAYTIME HEATING TO SLOWLY LIFT THIS LOWER
DECK SO THAT BY MID AFTERNOON CIGS SHUD RECOVER ABV VFR THRESHOLD.
SOUTH OF HWY 2 CORRIDOR EXPECT MAINLY VFR CONDS WITH AN INCREASING
VFR CLD DECK IN THE AFTERNOON. NORTHERLY BLAYER WINDS GUSTING FROM
10 TO 20 MPH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...MAKOWSKI
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1000 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1000 AM CDT FRI AUG 9 2013
CANADIAN RADARS CONTINUE TO SHOW SOME WEAK RETURNS DROPPING SOUTH
ASSOCIATED WITH A WEAK SHORTWAVE TROUGH ROTATING TOWARDS THE BASE
OF THE BROAD UPPER LOW OVER EASTERN CANADA. EXTENDED LOW POPS FOR
TODAY WESTWARD A BIT INTO THE NORTHERN VALLEY...BUT ANTICIPATE ANY
SHOWERS WILL REMAIN LIGHT AND RATHER ISOLATED. AFTERNOON TEMPS
WILL BE SIMILAR TO THE PAST FEW DAYS...ALTHOUGH NORTHWEST WINDS
WILL BE GUSTY AT TIMES.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 1000 AM CDT FRI AUG 9 2013
AREA OF MVFR CIGS PUSHING SOUTHWARD FROM MANITOBA SHUD OVERSPREAD
THE FAR NORTHERN FA DONW TO THE US HWY 2 CORRIDOR BY EARLY
AFTERNOON. EXPECT DATIME HEATING TO SLOLY LIFT THIS LOWER DECK SO
THAT BY MID AFTERNOON CIGS SHUD RECOVER ABV VFR THRESHOLD. SOUTH OF
HWY 2 CORRIDOR EXPECT MAINLY VFR CONDS WITH AN INCREASING VFR CLD
DECK IN THE AFTERNOON. NORTHERLY BLAYER WINDS GUSTING FROM 10 TO 20
MPH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...MAKOWSKI
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...GUST
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
655 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 655 AM CDT FRI AUG 9 2013
MADE SLIGHT ADJUSTMENTS TO HOURLY TEMPERATURES AND SKY COVER BASED
ON LATEST OBSERVATIONS. OTHERWISE...FORECAST IS ON TRACK WITH NO
MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 655 AM CDT FRI AUG 9 2013
VFR CONDITIONS WILL PERSIST AT ALL TAF SITES THROUGH 12 UTC
SATURDAY. CLEAR SKIES THIS MORNING WILL GIVE WAY TO SCT-BKN CU
LATE THIS MORNING AND AFTERNOON IN THE 4-5 KFT LAYER AGL...
ESPECIALLY ACROSS NORTHEAST ND INTO NORTHWEST MN. NORTHWEST
WINDS WILL INCREASE LATER THIS MORNING FROM 10 TO 15 KTS BEFORE
DECREASING AFTER SUNSET THIS EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
354 AM CDT FRI AUG 9 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1137 PM CDT THU AUG 8 2013
VFR CONDITIONS THROUGH THE PERIOD. SCATTERED 5-8K FT CLOUDS
TONIGHT INTO FRI AM THEN LIKELY BROKEN CUMULUS DEVELOPMENT ESP NE
ND INTO NRN MN WITH DAYTIME HEATING FRI AFTN IN THE 5-7K FT RANGE.
WINDS LIGHT/VARIABLE TONIGHT AND GENERALLY NORTHWEST 5 TO 10 KTS
FRIDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
129 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 130 AM CDT FRI AUG 9 2013
EMBEDDED MID LEVEL ENERGY/SUBTLE SHORTWAVE TROUGHS CONTINUE TO
TRACK ACROSS THE REGION IN NORTHWEST FLOW ALOFT. THUS FAR MAIN
RESULT HAS BEEN AN INCREASE IN MID LEVEL CLOUDS OVER WEST AND
CENTRAL NORTH DAKOTA. SCATTERED SHOWERS OVER NORTHEAST MONTANA
MOVING SLOWLY SOUTHEAST. FOR NOW LEFT THE FORECAST DRY ACROSS MY
WEST AS UNSURE WHETHER THESE SHOWERS WILL MAKE IT TO THE WESTERN
ND BORDER OR NOT. LINE OF THUNDERSTORMS FROM SOUTHEAST MONTANA INTO
THE BLACK HILLS OF WESTERN SOUTH DAKOTA NEAR A STATIONARY
BOUNDARY. A FEW MODELS TRY TO DEVELOP PRECIPITATION OVER MY
SOUTHWEST BETWEEN NOW AND 12Z...POSSIBLY ASSOCIATED WITH THE WAVE
GENERATING SHOWERS NORTH OF GLASGOW/WOLF POINT AT THE MOMENT.
MAIN UPDATE WAS TO INCREASE CLOUDS A BIT WEST AND CENTRAL...AND
ADJUST HOURLY WEATHER ELEMENTS BASED ON LATEST OBSERVATIONS/TRENDS.
UPDATE ISSUED AT 906 PM CDT THU AUG 8 2013
LATEST SATELLITE IMAGERY AND REGIONAL RADAR SHOWS THE SHORTWAVE IN
FAR SOUTHERN SASKATCHEWAN IS WEAKENING WITH TIME AS SHOWERS
CONTINUE TO WEAKEN AS THEY MOVE INTO FAR NORTHWEST NORTH DAKOTA.
WILL CARRY A SLIGHT CHANCE FOR THE NEXT HOUR OR TWO MAINLY FOR
DIVIDE COUNTY. OTHERWISE DRY AND MOSTLY CLEAR FOR ALL AREAS EXCEPT
IN THE FAR SOUTHWEST WHERE CLOUD DEBRIS IS QUICKLY APPROACHING FAR
SOUTHEAST MONTANA AND NORTHWEST SOUTH DAKOTA. THE RAP MAINTAINS
SOME LIGHT PRECIPITATION CHANCES DEVELOPING IN THE FAR SOUTHWEST
AS A SHORTWAVE PUSHES THROUGH SOUTH CENTRAL MONTANA. INSTABILITY
REMAINS WEAK AND WILL CONTINUE TO MONITOR FOR THE POSSIBILITY OF A
SHOWER OR TWO DEVELOPING AFTER MIDNIGHT...HOWEVER THE 00Z NAM IS
DRY...SO NOT REAL CONFIDENT IN THIS OCCURRING. LOOKING AHEAD...SLIGHTLY
BETTER INSTABILITY REACHES FAR SOUTHWESTERN NORTH DAKOTA FRIDAY
AFTERNOON/EVENING FOR CHANCE OF SHOWERS AND THUNDERSTORMS. WILL
ADJUST SKY GRIDS IN THE NORTHWEST AND SOUTHWEST TO ACCOUNT FOR THE
INCREASE IN CLOUDS. OTHER UPDATES WERE MAINLY TO HOURLY SENSIBLE
WEATHER ELEMENTS.
UPDATE ISSUED AT 457 PM CDT THU AUG 8 2013
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW CONTINUING WITH AN
UPSTREAM MID LEVEL SHORTWAVE LOCATED IN SOUTH CENTRAL SASKATCHEWAN.
REGIONAL RADAR SHOWS ISOLATED RAIN SHOWERS JUST NORTH OF THE MONTANA
BORDER MOVING SOUTHEAST WITH TIME. LIGHT RAIN AT SWIFT CURRENT PER
LATEST SURFACE OBSERVATIONS AND THE GFS HAS THE BEST HANDLE ON THE
PRECIPITATION AREA...WITH THE RAP NOT FAR BEHIND. THE GFS HOLDS A
THIN AREA OF LIGHT SHOWERS TOGETHER AS THEY MOVE INTO NORTHWESTERN
NORTH DAKOTA THIS EVENING AND WILL FOLLOW. THE RAP SHOWS A WEAKENING
OF THE SHOWERS AND KEEPS IT DRY. BASED ON THE LATEST RADAR AND
SURFACE OBSERVATIONS...THINK ENOUGH EVIDENCE UPSTREAM AND IN THE
GFS SOLUTION TO SOLIDIFY A MENTION OF ISOLATED SHOWERS NORTHWEST
INTO PORTIONS OF NORTH CENTRAL TONIGHT. THE GFS H7-H5 RELATIVE
HUMIDITY FIELD ALSO MATCHES THE VISIBLE SATELLITE IMAGERY WELL WHEN
OVERLAID AND THUS WILL INCREASE SKY GRIDS A BIT TO CAPTURE THIS.
ALSO AS MENTIONED FROM THE PREVIOUS DISCUSSION BELOW THE OTHER INTEREST
OVERNIGHT COULD BE OUR FAR SOUTHWEST ZONES...WHERE CONVECTION OVER
NORTHERN WYOMING THIS AFTERNOON IS FORECAST TO BUILD FURTHER NORTH
AND POSSIBLY SEEP INTO THE SOUTHWEST BY AROUND 04Z FRIDAY...PER
RAP MODEL. THE HRRR MODEL HAS CHANGED ITS COURSE BY KEEPING THE
REFLECTIVITY`S SOUTH WHEREAS EARLIER IT ALSO MAKE A TRACK INTO
SOUTHWEST NORTH DAKOTA. WILL CONTINUE TO MONITOR...OTHERWISE
MOSTLY CLEAR TO PARTLY CLOUDY SKIES CAN BE ANTICIPATED FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING INTO TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
CURRENTLY...HIGH PRESSURE CONTINUES TO BUILD ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE COOL HIGH PRESSURE SUPPRESS AND
THUNDERSTORM ACTIVITY LAT THIS AFTERNOON AND TONIGHT. BUT A FEW
SPRINKLES OR AN ISOLATED SHOWER CANNOT BE RULED OUT LATE THIS
AFTERNOON.
TONIGHT...THE SURFACE HIGH PRESSURE RIDGE REMAINS SITUATED
NORTHWEST TO SOUTHEAST ACROSS THE CWA...WHILE SHORTWAVE ENERGY
APPROACHES EASTERN NORTH DAKOTA AND ALSO SOUTHWEST NORTH DAKOTA.
THIS WILL LIKELY RESULT IN LITTLE MORE THAN INCREASING CLOUDS OVER
THE SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT. SOME OF THE MODELS
ARE INDICATING VERY LIGHT QPF IN THE SOUTHWEST BETWEEN 06-12Z
FRIDAY. BUT FOR NOW KEPT WITH THE CURRENT DRY FORECAST. EXPECT A
COOL NIGHT WITH HIGHS RANGING FROM THE MID 40S FAR NORTH TO THE
LOW TO MID 50S FAR SOUTH.
SHORTWAVE ENERGY WORKING THROUGH A NORTHERN ROCKIES UPPER RIDGE
WILL SUPPORT SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST
MONTANA...NORTHERN WYOMING AND WESTERN SOUTH DAKOTA FRIDAY
AFTERNOON. IT IS POSSIBLE THAT A FEW OF THESE SHOWERS OR
THUNDERSTORMS COULD MOVE INTO THE SOUTHWEST FRIDAY AFTERNOON.
HOWEVER...GUIDANCE CONTINUES TO TREND FARTHER SOUTH SO WILL
CONTINUE WITH PERSISTENCE AND KEEP THINGS DRY ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
A SLOW WARMING TREND POTENTIALLY BACK TO NEAR NORMAL TEMPERATURES
NEXT WEEK WILL HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON NORTHWEST FLOW
ALOFT CONTINUING THROUGH MONDAY...BEFORE A POTENTIAL SHIFT OF THE
UPPER LEVEL RIDGE AXIS ACROSS THE NORTHERN PLAINS TUESDAY ONWARD.
THIS WOULD SUPPORT A SLOW WARMING TREND FROM THE RECENT BELOW NORMAL
TEMPERATURES TO WIDESPREAD HIGHS IN THE 80S BY MID TO LATE NEXT
WEEK. IN REGARDS TO PRECIPITATION CHANCES...THERE IS CHANCE OF
THUNDERSTORMS SATURDAY AND SATURDAY NIGHT AS THE LAST OF THE
SIGNIFICANT WAVES EMBEDDED IN NORTHWEST FLOW PROPAGATES ACROSS THE
NORTHERN PLAINS. THEREAFTER...THUNDERSTORM CHANCES HOLD OFF UNTIL
MID TO LATE NEXT WEEK WITH INCREASING MOISTURE TRANSPORT UNDER THE
RIDGE AHEAD OF LEE SURFACE LOW PRESSURE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 130 AM CDT FRI AUG 9 2013
VFR CONDITIONS THROUGH THE 06Z TAF PERIOD. WILL SEE SCT-BKN MID
LEVEL CLOUDS AT TIMES EARLY TO MID MORNING FOR ALL LOCATIONS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
149 AM EDT FRI AUG 9 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY PERSISTS INTO THE WEEKEND WITH ROUNDS OF
SHOWERS AND THUNDERSTORMS. COLD FRONT SAGS SLOWLY SOUTH THROUGH
VICINITY SATURDAY INTO SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
1015 PM UPDATE...
DECREASED POPS FURTHER THIS EVE MOST PLACES BASED ON RADAR
TRENDS...STILL KEEPING ISO COVERAGE WORDING THOUGH. HAVE SOME LKLY
IN N MTNS NEXT FEW HRS TO FOLLOW CONCENTRATION OF SHRA. STILL ON
TRACK FOR INCREASE IN SHRA TOWARD MORNING W HALF OF CWA.
745 PM UPDATE...
THINGS QUIETING DOWN THIS EVE WITH MOST OF THE SHRA CLOSER TO
FRONT IN OH. SOME SHRA NOTED TRAVERSING THRU THE MTNS AND
LOWLANDS. WITH HI RES MDLS NOT SHOWING MUCH THRU 06Z ASIDE FROM SE
OH...WILL DROP POPS MOST PLACES...GOING WITH MOSTLY ISO LATER THIS
EVE. THINK MORE SHRA IN THE CARDS...THOUGH...AS SFC FRONT TRIES
TO INCH S INTO PORTIONS OF SE OH. HRRR TRENDS BACK THIS UP WITH
SHRA MOVING BACK IN W HALF OF CWA AFTER 06Z.
PREVIOUS DISCUSSION BELOW...
ACTIVE WEATHER CONTINUES FOR THE NEAR TERM AND BEYOND...WITH THE
PRIMARY FORECAST CONCERN REVOLVING AROUND PRECIP AMOUNTS EXPECTED
ALONG WITH SUBSEQUENT FLOODING POTENTIAL.
AT 18Z RADAR DEPICTING A NORTH/SOUTH BROKEN LINE OF SHOWERS WITH
SOME THUNDER MOVING EASTWARD ACROSS THE CENTRAL PART OF THE FORECAST
AREA. SFC FRONT CURRENTLY LOCATED ROUGHLY JUST SOUTH OF CLEVELAND
OHIO W/SW-WARD TO JUST NORTH OF DAYTON OHIO...WITH EXPECTED
DEVELOPING SHOWERS/THUNDERSTORMS NEAR IT AS WELL. LINE OF SHOWERS
CURRENTLY BISECTING AREA WILL CONTINUE EAST INTO THE MOUNTAINS BY
LATE AFTERNOON...WITH SHOWERS/STORMS ON THE FRONT TO PUSH E/NE-WARD
AND EVENTUALLY MAKING INTO PARTS OF THE NW ZONES BY LATE
AFTERNOON/EARLY EVE. NOT EXPECTING MUCH IN THE WAY OF A SEVERE
THREAT WITH THESE STORMS FOR OUR AREA...BUT SIMILAR TO YESTERDAY...A
MARGINAL THREAT FOR A SEVERE STORM EXISTS MAINLY TO THE NORTH AND
NORTHWEST OF THE FORECAST AREA.
OVERNIGHT ANY ONGOING CONVECTION WILL CONTINUE TO SLIDE EASTWARD
MAINLY ACROSS NORTHERN ZONES WHILE DIMINISHING IN COVERAGE AND
STRENGTH AS INSTABILITY WANES. SHOULD SEE THE NORMAL LULL IN
OVERNIGHT PRECIP COVERAGE INITIALLY BUT WILL LEAVE LOW/MID CHANCE
POPS IN THE EARLY OVERNIGHT HOURS. BY AND AFTER 06Z THE NEXT IN THE
SERIES OF VORT MAXES APPROACHES THE WESTERN ZONES WITH SFC LOW
RIDING ALONG THE STALLED FRONT JUST TO THE NW OF THE AREA. TOUGH TO
KNOW HOW MUCH TO INCREASE POPS WITH THESE FEATURES BUT WILL BRING IN
HIGHER POPS ACROSS THE WEST QUICKER THAN THE USUAL DIURNAL
TREND...BY 09Z-12Z FRI. THIS VORT MAX QUICKLY PUSHES OFF TO THE EAST
WHILE BEING REPLACED BY A STRONGER VORT MAX PROGGED TO MOVE ACROSS
NORTHERN ZONES DURING THE AFTERNOON. AS SFC LOW CONTINUES TO PULL
AWAY TO THE NORTH THE COLD FRONT ATTEMPTS TO PUSH SOUTHEAST A BIT
AND FOR A TIME AFTER 18Z FRI-00Z SAT MAY BE LOCATED OVER OUR SE OHIO
ZONES. STILL EXPECT THE HIGHEST GENERAL COVERAGE OF PRECIP TO BE
NEAR AND OUT AHEAD OF THE VORT MAX BUT MAY SEE SOME REDEVELOPMENT
ALONG THE FRONT ITSELF FURTHER WEST.
REGARDING FLASH FLOODING POTENTIAL...THE GENERAL CONSENSUS OF PRECIP
MODEL OUTPUT RUNNING AROUND 1.00IN - 1.50IN. THE AREA IS AND HAS
BEEN MOSTLY DRY RECENTLY. WHILE NOT APPEARING TO BE A WIDESPREAD
FLOOD THREAT...WITH TALL STORMS AND PWATS AT AND OVER 2.00IN AND
STORM MOTION AROUND 10-15KTS...STORMS SHOULD BE GOOD RAINMAKERS.
WILL CONTINUE THE FLASH FLOOD WATCH MAINLY FOR THE POTENTIAL OF SOME
LOCALIZED FLASH FLOODING...WITH THE HIGHEST THREAT APPEARING TO COME
EARLY FRIDAY AT THIS POINT IN TIME.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
FRONTAL BOUNDARY STALLED OUT ALONG NORTHERN ZONES FRIDAY NIGHT...BUT
WILL SLOWLY SAG SOUTH ACROSS THE CWA ON SATURDAY...WITH A GRADUAL
DRYING TREND NORTH TO SOUTH AS IT DOES SO. KEPT HEAVY RAIN WORDING
INT HE FORECAST FOR FRIDAY NIGHT...AS PW VALUES ARE PROGGED TO STILL
BE OVER 2 INCHES. FRONTAL BOUNDARY WILL END UP TO THE SOUTH OF THE
CWA BY SUNDAY MORNING. WILL STILL BE A CHANCE FOR SOME SHOWER/STORM
ACTIVITY ALONG THE EXTREME SOUTHERN/EASTERN ZONES AS WAVES CONTINUE
TO PUSH EAST ACROSS THE FRONTAL BOUNDARY...BUT THE BULK OF THE CWA
SHOULD BE IN DRIER...AND SOMEWHAT COOLER WEATHER. AS WITH PREVIOUS
FORECAST...CONTINUED TO TREND MORE TOWARDS THE GFS/ECMWF SOLUNS
WHICH INDICATE A WAVE...AND THUS HIGHER POPS MOVING ACROSS
SOUTHERN/CENTRAL ZONES FRIDAY NIGHT/SATURDAY.
AS STATED PREVIOUSLY...THE FFA MAY BE ABLE TO BE TRIMMED EARLY
ACROSS THE NORTHERN ZONES FRIDAY NIGHT AS THIS FRONTAL BOUNDARY
STARTS TO SINK SOUTH ACROSS THE CWA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD STARTS OUT DRIER AS FRONTAL BOUNDARY TO THE SOUTH OF
THE CWA...AND HIGH PRESSURE BRIEFLY BUILDS IN FROM THE NORTH.
HOWEVER...MOISTURE AND HUMIDITY WILL BE ON THE INCREASE ONCE AGAIN
BY LATE MONDAY NIGHT INTO TUESDAY...AS A LOW PRESSURE SYSTEM...AND
COLD FRONTAL BOUNDARY APPROACH AND MOVE THROUGH THE AREA THROUGH MID
WEEK. INCREASED POPS TO AT LEAST CHANCE-HIGH CHANCE CATEGORY
EARLY-MID WEEK. COULD SEE HEAVY DOWNPOURS ASSOCIATED WITH ANY
SHOWERS/STORMS AS PW VALUES WILL ONCE AGAIN RISE UP TO AROUND
1.7-1.9 INCHES...AND DEPENDING ON WHAT HAPPENS OVER THE NEXT FEW
DAYS/INTO THE WEEKEND...COULD DETERMINE WHETHER OR NOT ANY LOCALIZED
WATER ISSUES WILL BE A CONCERN.
FRONTAL BOUNDARY SINKS TO THE SOUTH ON THURSDAY...WITH DRIER AND
COOLER WEATHER IN ITS WAKE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
06Z FRIDAY THRU 06Z SATURDAY...
VERY MOIST AND UNSTABLE AIRMASS IN PLACE WITH THREAT OF SHOWERS AND
STORMS IN OUR COUNTY WARNING AREA(CWA). WITH THE MODEL AGREED MAIN
SHORT WAVE...BEST CHANCE OF RAIN WILL BE ACROSS THE NORTH THRU
15Z...SHIFTING INTO CENTRAL PORTIONS THIS AFTERNOON AND INTO THE
SOUTH TONIGHT.
06Z THRU 15Z...BECOMING GENERALLY MVFR IN CEILINGS AND FOG BY
08Z...WITH OCCASIONAL IFR IN RAIN ACROSS THE NORTH ESPECIALLY ALONG
AND NORTH OF A PKB-CKB-EKN LINE.
AFTER 15Z...CONTINUED MVFR CONDITIONS...ACROSS NORTHERN AND CENTRAL
PORTIONS...ESPECIALLY HTS-CRW-EKN WHERE BEST CHANCE OF RAIN WILL BE.
BECOMING VFR CEILINGS NORTH OF PKB-CKB LINE BY 18Z AND FAR SOUTH
INCLUDING BKW.
AFTER 00Z...BEST CHANCE OF RAIN AND MVFR CONDITIONS MAINLY ACROSS
THE SOUTH HALF ESPECIALLY AFFECTING BKW. ELSEWHERE GENERALLY VFR
CEILINGS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING OF FLIGHT CONDITIONS MAY BE HIGHLY
VARIABLE OVERNIGHT AND TOMORROW.
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 FRI 08/09/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY M M M H H H H H H H H H
HTS CONSISTENCY M M M M H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M L M M M M L H H M M L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H L H H H H M
AFTER 06Z SATURDAY...
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...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...50/SL
NEAR TERM...50/30
SHORT TERM...SL
LONG TERM...SL
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
136 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ARES OF SHOWERS WERE SHOWING TRAINING ECHOS OVER PORTIONS OF
SOUTHEAST INDIANA. UPDATED THE FORECAST TO ACCOUNT FOR THE
CATEGORICAL NATURE OF THE SHOWERS AND THUNDERSTORMS IN THIS AREA
WITH AN EXPECTATION THAT THEY WILL PROGRESS TO THE EAST-SOUTHEAST
OVERNIGHT. TEMPERATURES AND DEWPOINTS WERE BLENDED WITH OBSERVED
VALUES AND WERE ON TRACK AS NEAR AS I COULD SEE.
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
EFFECTIVE FRONTAL BOUNDARY MAY HAVE SLID A LITTLE FARTHER SOUTH
THIS EVENING DUE TO RECENT CONVECTION AS SEEN ON MOSAIC RADAR.
THIS MAY PLAY A PART IN WHERE THE BEST COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR OVERNIGHT. CONVECTION CURRENTLY OVER THE
REGION HAS SHOWN A DOWNWARD TREND WITH THE DIURNAL CYCLE.
HOWEVER...AN UPTICK IS EXPECTED AGAIN LATER THIS EVENING AND
OVERNIGHT AS AN UPSTREAM MCV OVER SE ILLINOIS TRAVELS EAST THROUGH
THE OHIO VALLEY. ASSOCIATED SUBTLE LOW LEVEL JET/850 MB MOISTURE
TRANSPORT AND A WEAKLY REFLECTED SFC WAVE MAY ALLOW SHOWERS AND
THUNDERSTORMS TO BECOME MORE FOCUSED SOUTH OF THE DAYTON AND
COLUMBUS AREAS...IN OTHER WORDS...ALONG AND SOUTH OF THE OHIO
RIVER BASED ON LATEST MODEL RUNS. BUT GIVEN OSCILLATING SOLUTIONS
FROM RUN TO RUN...AM HESITANT AT THIS TIME TO CUT BUT THE FFA FOR THE
DAYTON AND COLUMBUS AREAS. SO WILL LET THIS HOLD AT THIS TIME BUT
MENTION THAT BETTER COVERAGE MAY BE CLOSER TO THE OHIO RIVER. THE
AIRMASS TONIGHT WILL BE VERY MOIST...PWATS IN EXCESS OF 2
INCHES...AND WARM CLOUD DEPTHS WILL BE FAVORABLE FOR
COLLISION/COALESCENCE PROCESSES. SO THE HEAVY RAIN THREAT WILL
CONTINUE...WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR OR
PERHAPS IN SLIGHTLY LESSER TIMES GIVEN FAVORABLE ENVIRONMENT.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT OF THE FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
MVFR VSBYS AND CIGS WILL BE LIKELY THROUGH THE REMAINDER OF
TONIGHT AS A DISTURBANCE BRINGS LIGHT PRECIPITATION TO MOST OF
OUR TERMINALS. THERE COULD BE SOME LOWERING OF CIGS TO IFR AS WE
GET CLOSER TO SUNRISE. MOST PRECIPITATION WILL EXIT THE AREA AFTER
SUNRISE AND OUR LOW CIGS SHOULD SCATTER BY MID MORNING. THIS WILL
LEAVE THE AREA WITH VFR CONDITIONS FROM MID MORNING THROUGH THE
EVENING.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH UNTIL 8 AM EDT THIS MORNING FOR OHZ045-046-
051>056-060>065-070>072.
FLASH FLOOD WATCH THROUGH THIS EVENING FOR OHZ073-074-077>082-
088.
KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH UNTIL 8 AM EDT THIS MORNING FOR INZ050-058-
059-066-073-074.
FLASH FLOOD WATCH THROUGH THIS EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS TULSA OK
759 PM CDT SAT AUG 10 2013
.DISCUSSION...
ZONES UPDATED TO REFLECT NON-PRECIP THIS EVENING...
AT LEAST THROUGH 06Z. AFTER LOOK AT 00Z WRF AND
LATEST HRRR MAY SCALE POPS BACK MORE WITH 945 PM
EVENING UPDATE. GW
&&
.PREV DISCUSSION... /ISSUED 629 PM CDT SAT AUG 10 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
AFTERNOON CU FIELD WILL DISSIPATE OVER THE NEXT FEW
HOURS...ALTHOUGH SHOULD SEE MVFR CIGS REDEVELOP AFTER
06Z FOR MOST LOCATIONS. COULD HAVE SOME SHOWERS DEVELOP
TOWARD DAYBREAK IN WESTERN AR...ALTHOUGH CONFIDENCE ISN`T
HIGH ENOUGH TO INCLUDE IN TAFS AT THIS TIME.
PREV DISCUSSION... /ISSUED 253 PM CDT SAT AUG 10 2013/
DISCUSSION...
FRONTAL BOUNDARY CURRENTLY STALLED IN THE HIGHER TERRAIN OVER FAR
SOUTHEAST OKLAHOMA....EXTENDING INTO WEST CENTRAL ARKANSAS.
FURTHER BEHIND THE FRONT MILD CONDITIONS FOR THIS TIME OF YEAR
WITH TEMPERATURES RUNNING IN THE LOWER 80S ACROSS NORTHEAST
OKLAHOMA.
IN THE SHORT TERM...COULD SEE A FEW PULSE STRONG/POSSIBLY SEVERE
THUNDERSTORMS DEVELOP ACROSS FAR SOUTHEAST OKLAHOMA AND WEST
CENTRAL ARKANSAS NEAR FRONTAL BOUNDARY THROUGH THIS EVENING.
DAMAGING WINDS AND HEAVY RAINFALL WILL BE THE PRIMARY THREAT IN
THE STRONGER CELLS. DEPENDING ON HOW LONG STORMS LINGER INTO THE
OVERNIGHT HOURS...COULD SEE A FEW ISOLATED AREAS HAVE A LIMITED
FLASH FLOOD THREAT.
FOCUS TURNS TO EARLY NEXT WEEK WITH THE POTENTIAL FOR ANOTHER
HEAVY RAIN EVENT ACROSS MUCH OF THE AREA. MODELS IN GENERAL
AGREEMENT WITH DEVELOPING STRONGER NORTHWEST FLOW ALOFT DURING
THIS TIME AS LARGE SCALE TROUGH SWINGS THROUGH THE GREAT LAKES
REGION. PRECIPITATION CHANCES WILL INCREASE BY MONDAY AFTERNOON
AS MOIST/UNSTABLE AIR-MASS DEVELOPS. STORMS EXPECTED TO FORM INTO
A LARGER CONVECTIVE COMPLEX INTO MONDAY NIGHT WITH THE POTENTIAL
FOR HEAVY RAINFALL/FLOODING. HEAVY RAIN THREAT WILL CONTINUE
TUESDAY INTO EARLY WEDNESDAY BEFORE COLD FRONT SWEEPS THROUGH THE
ENTIRE AREA. DRY/MILD CONDITIONS AGAIN EXPECTED BY LATE NEXT
WEEK AS HIGH PRESSURE BUILDS OVER THE CENTRAL/SOUTHERN PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 69 91 74 91 / 10 10 20 50
FSM 74 91 74 92 / 40 30 20 40
MLC 71 94 73 95 / 20 20 20 40
BVO 66 90 70 90 / 10 10 20 50
FYV 68 88 69 89 / 40 30 20 50
BYV 68 85 70 88 / 40 30 20 50
MKO 70 91 72 92 / 20 20 20 50
MIO 66 90 71 88 / 10 10 20 50
F10 70 92 73 93 / 10 10 20 40
HHW 75 96 75 96 / 30 20 20 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...21
LONG TERM....21
AREA FORECAST DISCUSSION
NWS NORMAN OK
1210 AM CDT FRI AUG 9 2013
.AVIATION... WIDESPREAD SHOWERS AND THUNDERSTORMS WILL CONTINUE
EARLY IN THE PERIOD WITH PREVAILING OR TEMPO GROUPS AT ALL BUT FAR
SRN SITES. POST FRONTAL MVFR CIGS MAY SPREAD THROUGH NRN AND INTO
CNTRL OK THROUGH THE EARLY MORNING HOURS THEN BECOMING VFR DURING
THE AFTN.
&&
.PREV DISCUSSION... /ISSUED 647 PM CDT THU AUG 8 2013/
.AVIATION...
SEVERAL SMALL CLUSTERS OF STORMS HAVE FORMED DURING THE
LATE AFTERNOON AND EARLY EVENING IN SOUTHWEST OK AND
WESTERN NORTH TEXAS. RECENT HRRR RUNS SUGGEST BETTER ORGANIZATION
MAY OCCUR AS PRECIP/STORMS MOVE NORTHEAST THIS EVENING. IF THIS
OCCURS MOST OF THE PRECIP MAY CLEAR SOUTHWEST OK AND NORTH TEXAS
BY THE LATE EVENING. ADDITIONAL STORMS MAY IMPACT WESTERN AND
NORTHERN OKLAHOMA LATE THIS EVENING AND OVERNIGHT. MVFR CEILINGS
AND VISIBILITIES MAY OCCUR WITH THE STRONGER STORMS THIS
EVENING AND OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 328 PM CDT THU AUG 8 2013/
DISCUSSION...
EXTENSIVE CLOUD COVER HELD DOWN TEMPERATURES FOR MOST OF THE
DAY...GREATLY LIMITING INSTABILITY AND DELAYING THE FORMATION OF
SHOWERS/THUNDERSTORMS. THE CLOUD COVER HAS DIMINISHED ACROSS THE
WESTERN HALF OF OUR FORECAST AREA...ALLOWING RAPID WARMING AND
DESTABILIZATION. A FEW THUNDERSTORMS FORMED QUICKLY WITHIN THE
PAST HOUR JUST OUTSIDE OUR FORECAST AREA IN TEXAS. ADDITIONAL
DEVELOPMENT IS LIKELY...BUT THE EXACT LOCATION IS STILL UNCLEAR.
THERE IS ALSO SOME UNCERTAINTY REGARDING THE EVENTUAL FORMATION OF
ANOTHER MCS OVERNIGHT...BUT IT STILL SEEMS MOST PROBABLE THAT
NORTHERN OKLAHOMA WILL BE THE TARGET OF ANY CONVECTIVE SYSTEMS
THAT MAY DEVELOP TONIGHT. AS A RESULT...THE EXPECTED RAINFALL
COULD CAUSE FLOODING PROBLEMS...AND A FLOOD WATCH HAS BEEN ISSUED
FOR TONIGHT THROUGH MIDDAY TOMORROW.
IT APPEARS THAT THE SUPPORT FOR CONTINUED CONVECTION WILL DIMINISH
TOMORROW...CAUSING LOWER CHANCES OF RAIN AND STORMS...LESS
QPF...AND LESS CHANCE OF ADDITIONAL FLOODING. RIVERS MAY CONTINUE
TO FLOOD...BUT OTHERWISE THE RISK IS MUCH LOWER TOMORROW AFTERNOON
INTO THE WEEKEND.
THE OVERALL PATTERN REMAINS FAVORABLE FOR OCCASIONAL SHOWERS AND
THUNDERSTORMS THROUGH THE PERIOD...WITH TEMPERATURES RUNNING
FAIRLY CLOSE TO THE SEASONAL AVERAGES.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 73 90 71 90 / 60 30 20 10
HOBART OK 73 91 69 92 / 60 20 20 10
WICHITA FALLS TX 75 98 73 96 / 40 20 20 10
GAGE OK 68 80 65 87 / 60 20 10 10
PONCA CITY OK 71 85 68 85 / 70 30 20 10
DURANT OK 74 100 74 97 / 30 20 20 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH FRIDAY AFTERNOON
FOR OKZ004>008-010>013.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEDFORD OR
849 PM PDT SAT AUG 10 2013
.SHORT TERM...THE UPPER LOW ALONG THE OREGON COAST WILL GRADUALLY
MOVE NORTH TONIGHT INTO SUNDAY MORNING. EXPECT CONTINUED ISOLATED
TO SCATTERED SHOWERS THIS EVENING INTO TONIGHT WITH THIS LOW IN
THE AREA. HOWEVER THUNDERSTORM ACTIVITY HAS DECREASED FOR MUCH OF
THE CWA. BASED ON THE CURRENT TRENDS AND MODEL FORECASTS, EXPECT
ONLY A SLIGHT CHANCE FOR THUNDERSTORMS THIS EVENING INTO TONIGHT
OVER THE AREA, EXCEPT IN CENTRAL SISKIYOU COUNTY WHERE SCATTERED
THUNDERSTORMS MAY CONTINUE THROUGH THE EVENING AS A WEAK
DISTURBANCE CONTINUES TO MOVE OVER THE AREA.
SUNDAY...THE LOW IS FORECAST TO SHIFT NORTH OF THE CWA WITH
SOUTHWEST FLOW ALOFT DEVELOPING OVER THE AREA. MODELS CONTINUE TO
SHOW ISOLATED THUNDERSTORMS AND SHOWERS DEVELOPING IN THE
AFTERNOON AND EVENING, MAINLY ALONG THE CASCADES AND JUST TO THE
EAST IN OREGON AS WELL AS IN SISKIYOU COUNTY IN NORTHERN
CALIFORNIA.
UPDATED THE EVENING GRIDS TO SHOW DECREASED CHANCES FOR
THUNDERSTORMS.
&&
.AVIATION...THIS EVENING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WILL CONTINUE INLAND. ALONG THE COAST WIDESPREAD MVFR CIGS HAVE
DEVELOPED. MVFR CIGS WILL CONTINUE OVERNIGHT INTO SUNDAY MORNING ALONG
THE COAST WITH AREAS OF IFR CIGS AND LOCAL IFR VISIBILITIES
DEVELOPING LATE TONIGHT THROUGH EARLY SUNDAY MORNING. ALSO EXPECT
THE MVFR CIGS TO SPREAD INLAND INTO DOUGLAS AND JOSEPHINE COUNTIES
BETWEEN 05Z- 10Z, PERSISTING THROUGH MID TO LATE MORNING BEFORE
LIFTING TO VFR AROUND 17Z AND PARTIALLY CLEARING. ALONG THE
COAST...EXPECT CLEARING DURING THE LATE MORNING AND EARLY
AFTERNOON BETWEEN 18Z- 21Z. ADDITIONALLY SHOWERS AND THUNDERSTORMS
SUNDAY AFTERNOON AND EVENING WILL BE MORE ISOLATED, PRIMARILY
ALONG AND NEAR THE CASCADE CREST. BTL/CC
&&
.PREV DISCUSSION... /ISSUED 221 PM PDT SAT AUG 10 2013/
DISCUSSION...THE UPPER LOW CONTINUES TO SPIN OVER SOUTHWEST
OREGON WITH SEVERAL SHORTWAVES MOVING THROUGH TODAY. THUNDERSTORMS
ARE ALREADY BLOWING UP ALONG THE CASCADES AND EASTERN DOUGLAS
COUNTY. MEANWHILE THE MID LEVEL CLOUD SHIELD IN WESTERN SISKIYOU
COUNTY IS ERODING...SO IT COULD BE A TIMING ISSUE AS TO HOW MUCH
THUNDERSTORM ACTIVITY DEVELOPS IN NORTHERN CAL...JOSEPHINE AND
JACKSON COUNTIES. FURTHER NORTH THUNDERSTORMS WILL CONTINUE TO
INCREASE IN COVERAGE THROUGH EARLY THIS EVENING WITH SOME THAT COULD
BE MODERATE TO SEVERE PRODUCING MODERATE TO HEAVY RAIN...HAIL AND
GUSTY OUTFLOW WINDS. MODIFIED THE MORNING SOUNDING FOR THAT IT`S
EXPECTED TO LOOK LIKE THIS AFTERNOON AND IT`S SHOWING CAPE VALUES
NEAR 1400 J/KG AND PRECIPITABLE WATER VALUES NEAR AN INCH AND LIFTED
INDICES NEAR -6. THE RAP 13 AND LOCAL HRRR MODELS PUT MOST OF THE
QPF ALONG AND WEST OF THE CASCADES AND HAVE THUS INCREASED POPS AND
QPF IN THESE AREAS. HOWEVER MID LEVEL MOISTURE WILL INCREASE IN
NORTHERN KLAMATH AND LAKE COUNTIES WITH AT THE SAME TIME SHORTWAVES
ARE APPROACHING. SO EXPECT THIS AREA TO SEE INCREASED ACTIVITY AS
WELL.
RIGHT NOW...NOT MUCH IS GOING ON IN MODOC AND SOUTHERN LAKE
COUNTY...BUT WERE GETTING CUMULUS DEVELOPMENT AND EXPECT SOME
ACTIVITY THERE LATE THIS AFTERNOON.
THE UPPER LOW WILL MOVE INTO THE NORTHWEST PART OF THE FORECAST AREA
TONIGHT WITH A SOUTHWEST FLOW ALOFT DEVELOPING. THUNDERSTORMS SHOULD
DECREASE LATER THIS EVENING...THEN THE FOCUS FOR STORMS TONIGHT IS
EXPECTED TO SHIFT OVER THE NORTHERN CASCADES...NORTHERN LAKE AND
KLAMATH COUNTIES.
THE UPPER LOW FINALLY MOVES NORTH OF THE AREA SUNDAY AND WE`LL GET
INTO A SOUTHWEST FLOW ALOFT. THE CASCADES...EASTSIDE AND PARTS OF
THE SISKIYOUS HAVE THE BEST CHANCE OF GETTING THUNDERSTORMS IN THE
AFTERNOON AND EARLY EVENING...BUT IT`S POSSIBLE ISOLATED STORMS
COULD DEVELOP ALONG THE SISKIYOUS.
THE UPPER LOW CONTINUES TO MOVE NORTH AND WEAKEN MONDAY WITH A
CONTINUED SOUTHWEST FLOW OVER THE AREA. THE HIGHEST CHANCE FOR
THUNDERSTORMS WILL BE ALONG THE CASCADES INTO NORTHERN LAKE AND
KLAMATH COUNTIES. EVEN THEN WERE NOT EXPECTING ANYTHING SIGNIFICANT.
THE EC AND GFS SHOW ANOTHER UPPER LOW SETTING SHOP WEST OF THE GULF
OF ALASKA WITH A CONTINUES SOUTHWEST FLOW OVER THE AREA. THIS WILL
RESULT IN DRY CONDITIONS WITH TEMPERATURES NEAR NORMAL. WHILE I
CANNOT RULE OUT ANY CHANCE OF PRECIPITATION EAST OF THE
CASCADES...THE ODDS ARE LOW THAT WE`LL GET ANYTHING. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT SUNDAY FOR ORZ027-030-031.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
CC
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
736 AM EDT FRI AUG 9 2013
.SYNOPSIS...
THE WARM MOIST AIR CONTINUES TO BRING SHOWERS TO THE REGION. A
COLD FRONT WILL BEGIN TO PUSH DRIER AIR INTO PENNSYLVANIA LATER
THIS AFTERNOON INTO EARLY SATURDAY. THE COLD FRONT WILL LIKELY
TRIGGER THUNDERSTORMS LATER TODAY. MUCH DRIER WILL MOVE OVER THE
ENTIRE REGION SATURDAY. A TROUGH BUILDS OVER NORTHEASTERN NORTH
AMERICA WHICH SHOULD KEEP US IN GENERALLY NORTHWEST FLOW MOST OF
THE NEXT 3-8 DAYS ENSURING WEAK FRONTAL PASSAGES AND GENERALLY LOW
HUMIDITY AND LOW PROBABILITY OF SIGNIFICANT RAINFALL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR CONTINUES TO SHOW SHOWERS AND EMBEDDED THUNDERSTORMS MOVING
OVER THE MOISTURE BOUNDARY OVER CENTRAL PENNSYLVANIA BEST DEFINED
IN THE LOW-LEVEL THETA-E GRADIENT. THE LARGER SCALE THETA GRADIENT
IS IMPLYING THE FRONTAL PUSH TO OUR NORTHWEST IS NOT INTO
NORTHWESTERNMOST PA. SHOWERS WILL BECOME MORE NUMEROUS IN THE WEST
OVER THE NEXT FEW HOURS.
THE WARM MOIST AIR AND ABOVE NORMAL PW HAVE KEPT THE MORNING LOWS
MAINLY IN THE UPPER 60S AND 70S. GOING TO BE A WARM MOIST DAY OVER
CENTRAL AND SOUTHEASTERN AREAS.
THE PROBABILITY OF RAIN SHOULD DROP OFF FAST IN THE NW THIS
AFTERNOON. MOST FORECASTS FROM SREF TO HRRR IMPLY BY MID- LATE
AFTERNOON THE THREAT OF RAIN IN NW PASSES. EVEN CENTRAL AREAS
NOW APPEAR TO HAVE A GOOD SHOW OF NICE LATER AFTERNOON AND EARLY
EVENING AS THE DRIER AIR SLIDES TO THE SOUTHEAST.
SHOWERS AND STORMS WITH LOCALLY HEAVY RAIN FROM A FEW STRONGER
CELLS WILL LINGER LONGER IN THE SOUTHEAST.
TEMPS MAINLY 70S IN NEW TO MID-UPPER 80S SOUTHEAST. WINDS SHOULD
BECOME MORE WESTERLY IN NW PA THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE MODELS ALL SHOW LOWER PW AIR FILTERING INTO PA FAST. DROPPED
ALL POPS IN CENTRAL AND NORTHERN AREAS BEFORE 8 PM. LOWERED POPS
FAST IN THE SOUTHEAST WITH NO RAIN OF NOTE MUCH AFTER MIDNIGHT
THEN THE DRYING OUT BEGINS. ENSEMBLES IMPLY BY 0300 UTC ALL THREAT
OF RAIN IS TO OUR SOUTH AND EAST.
SATURDAY SHOULD BE MOSTLY SUNNY WITH TEMPERATURES NEAR NORMAL. THE
850 HPA TEMPS DO NOT DROP BELOW NORMAL UNTIL AFTER THIS PERIOD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE COMING WEEK SHOULD BE RELATIVELY DRY AS MOST MODELS AT THIS
TIME AND ENSEMBLE FORECAST SYSTEMS (EFS) SHOW PW VALUES GENERALLY
NORMAL TO BELOW NORMAL. NOT A GOOD PATTERN FOR RAIN LET ALONE
HEAVY RAINFALL.
A MEAN TROUGH WILL DOMINATE THE EASTERN UNITED STATES WELL INTO
NEXT WEEK. SOME PIN WHEELING WAVES IMPLY CHANCES OF SCATTERED
SHOWERS SHOULD WE GET A ENOUGH MOISTURE OR INSTABILITY AHEAD OF
SOME OF THE WAVES. AT THIS TIME WE FLIRT WITH SOME MOISTURE TUES-WED
FOR SLIGHT INCREASE SHOWERS...NOT VERY IMPRESSIVE.
THE 850 HPA TEMPS ARE NORMAL TO SOME PERIODS WHERE THEY FALL
SLIGHTLY BELOW NORMAL. THE PW STAYS NORMAL TO BELOW NORMAL TOO.
THE PIN WHEELING TROUGHS OF COURSE PUSH THE WEAK SURGES OF COOLER
AND DRIER AIR IN.
THUS A GENERALLY COOL DRY WEEK IS CURRENTLY FORECAST.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
WIDE RANGE IN CONDITIONS THE LAST FEW HOURS.
MADE SOME ADJUSTMENTS TO THE 12Z TAFS.
SOME HEAVY SHOWERS DEVELOPING JUST EAST OF UNV NOW.
MORE WIDESPRED SHOWERS NOW TO THE WEST WITH THE FRONT.
EXPECT CONDITIONS TO IMPROVE FROM WEST TO EAST THIS AFT...
AS A WEAK COLD FRONT MOVES ACROSS THE AREA. DEWPOINTS ON
THE HIGH SIDE...BUT WINDS ALOFT NOT REAL STRONG FOR
SEVERE STORMS.
INTERESTING THING ABOUT DEWPOINTS. MAV GUIDANCE FCST A
DEWPOINT OF 75 IN MDT YESTERDAY. DEWPOINTS CAME UP HIGH...
BUT NOT THAT HIGH.
EXPECT SHOWERS AND STORMS TO TAPER OFF ACROSS THE FAR
SE ON SAT.
WEAK COLD ADVECTION TODAY INTO SAT...NOT A LOT OF COLD
ADVECTION BEFORE THE MIDDLE OF NEXT WEEK.
MAIN CONCERN WILL BE IF WE WILL GET FOG SAT AM...BEHIND
THE FRONT...AS TEMPS FALL TO NEAR THE CROSS OVER VALUE.
FOR NOW...HAVE FOG IN BFD.
LOOKS LIKE IT WILL BE MID WEEK...BEFORE ANY REAL DEEP
COLD AIR WORKS INTO CENTRAL PA.
OUTLOOK...
SAT...MVFR/IFR EARLY WITH PATCHY FOG...THEN VFR.
SUN-MON...GENERALLY VFR...BUT POSSIBLE AM RESTRICTIONS IN FOG.
TUE...VFR...BUT POSSIBLE RESTRICTIONS IN SHRA/TSRA WITH NEXT
COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
543 AM EDT FRI AUG 9 2013
.SYNOPSIS...
THE WARM MOIST AIR CONTINUES TO BRING SHOWERS TO THE REGION. A
COLD FRONT WILL BEGIN TO PUSH DRIER AIR INTO PENNSYLVANIA LATER
THIS AFTERNOON INTO EARLY SATURDAY. THE COLD FRONT WILL LIKELY
TRIGGER THUNDERSTORMS LATER TODAY. MUCH DRIER WILL MOVE OVER THE
ENTIRE REGION SATURDAY. A TROUGH BUILDS OVER NORTHEASTERN NORTH
AMERICA WHICH SHOULD KEEP US IN GENERALLY NORTHWEST FLOW MOST OF
THE NEXT 3-8 DAYS ENSURING WEAK FRONTAL PASSAGES AND GENERALLY LOW
HUMIDITY AND LOW PROBABILITY OF SIGNIFICANT RAINFALL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR CONTINUES TO SHOW SHOWERS AND EMBEDDED THUNDERSTORMS MOVING
OVER THE MOISTURE BOUNDARY OVER CENTRAL PENNSYLVANIA BEST DEFINED
IN THE LOW-LEVEL THETA-E GRADIENT. THE LARGER SCALE THETA GRADIENT
IS IMPLYING THE FRONTAL PUSH TO OUR NORTHWEST IS NOT INTO
NORTHWESTERNMOST PA. SHOWERS WILL BECOME MORE NUMEROUS IN THE WEST
OVER THE NEXT FEW HOURS.
THE WARM MOIST AIR AND ABOVE NORMAL PW HAVE KEPT THE MORNING LOWS
MAINLY IN THE UPPER 60S AND 70S. GOING TO BE A WARM MOIST DAY OVER
CENTRAL AND SOUTHEASTERN AREAS.
THE PROBABILITY OF RAIN SHOULD DROP OFF FAST IN THE NW THIS
AFTERNOON. MOST FORECASTS FROM SREF TO HRRR IMPLY BY MID- LATE
AFTERNOON THE THREAT OF RAIN IN NW PASSES. EVEN CENTRAL AREAS
NOW APPEAR TO HAVE A GOOD SHOW OF NICE LATER AFTERNOON AND EARLY
EVENING AS THE DRIER AIR SLIDES TO THE SOUTHEAST.
SHOWERS AND STORMS WITH LOCALLY HEAVY RAIN FROM A FEW STRONGER
CELLS WILL LINGER LONGER IN THE SOUTHEAST.
TEMPS MAINLY 70S IN NEW TO MID-UPPER 80S SOUTHEAST. WINDS SHOULD
BECOME MORE WESTERLY IN NW PA THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE MODELS ALL SHOW LOWER PW AIR FILTERING INTO PA FAST. DROPPED
ALL POPS IN CENTRAL AND NORTHERN AREAS BEFORE 8 PM. LOWERED POPS
FAST IN THE SOUTHEAST WITH NO RAIN OF NOTE MUCH AFTER MIDNIGHT
THEN THE DRYING OUT BEGINS. ENSEMBLES IMPLY BY 0300 UTC ALL THREAT
OF RAIN IS TO OUR SOUTH AND EAST.
SATURDAY SHOULD BE MOSTLY SUNNY WITH TEMPERATURES NEAR NORMAL. THE
850 HPA TEMPS DO NOT DROP BELOW NORMAL UNTIL AFTER THIS PERIOD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE COMING WEEK SHOULD BE RELATIVELY DRY AS MOST MODELS AT THIS
TIME AND ENSEMBLE FORECAST SYSTEMS (EFS) SHOW PW VALUES GENERALLY
NORMAL TO BELOW NORMAL. NOT A GOOD PATTERN FOR RAIN LET ALONE
HEAVY RAINFALL.
A MEAN TROUGH WILL DOMINATE THE EASTERN UNITED STATES WELL INTO
NEXT WEEK. SOME PIN WHEELING WAVES IMPLY CHANCES OF SCATTERED
SHOWERS SHOULD WE GET A ENOUGH MOISTURE OR INSTABILITY AHEAD OF
SOME OF THE WAVES. AT THIS TIME WE FLIRT WITH SOME MOISTURE TUES-WED
FOR SLIGHT INCREASE SHOWERS...NOT VERY IMPRESSIVE.
THE 850 HPA TEMPS ARE NORMAL TO SOME PERIODS WHERE THEY FALL
SLIGHTLY BELOW NORMAL. THE PW STAYS NORMAL TO BELOW NORMAL TOO.
THE PIN WHEELING TROUGHS OF COURSE PUSH THE WEAK SURGES OF COOLER
AND DRIER AIR IN.
THUS A GENERALLY COOL DRY WEEK IS CURRENTLY FORECAST.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
WIDE RANGE IN CONDITIONS THE LAST FEW HOURS.
MADE SOME ADJUSTMENTS TO THE 09Z TAFS.
SOME HEAVY SHOWERS DEVELOPING JUST EAST OF UNV NOW.
MORE WIDESPRED SHOWERS NOW TO THE WEST WITH THE FRONT.
EXPECT CONDITIONS TO IMPROVE FROM WEST TO EAST THIS AFT...
AS A WEAK COLD FRONT MOVES ACROSS THE AREA. DEWPOINTS ON
THE HIGH SIDE...BUT WINDS ALOFT NOT REAL STRONG FOR
SEVERE STORMS.
INTERESTING THING ABOUT DEWPOINTS. MAV GUIDANCE FCST A
DEWPOINT OF 75 IN MDT YESTERDAY. DEWPOINTS CAME UP HIGH...
BUT NOT THAT HIGH.
EXPECT SHOWERS AND STORMS TO TAPER OFF ACROSS THE FAR
SE ON SAT.
WEAK COLD ADVECTION TODAY INTO SAT...NOT A LOT OF COLD
ADVECTION BEFORE THE MIDDLE OF NEXT WEEK.
MAIN CONCERN WILL BE IF WE WILL GET FOG SAT AM...BEHIND
THE FRONT...AS TEMPS FALL TO NEAR THE CROSS OVER VALUE.
LOOKS LIKE IT WILL BE MID WEEK...BEFORE ANY REAL DEEP
COLD AIR WORKS INTO CENTRAL PA.
OUTLOOK...
SAT...MVFR/IFR EARLY WITH PATCHY FOG...THEN VFR.
SUN-MON...GENERALLY VFR...BUT POSSIBLE AM RESTRICTIONS IN FOG.
TUE...VFR...BUT POSSIBLE RESTRICTIONS IN SHRA/TSRA WITH NEXT
COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
510 AM EDT FRI AUG 9 2013
.SYNOPSIS...
THE WARM MOIST AIR CONTINUES TO BRING SHOWERS TO THE REGION. A
COLD FRONT WILL BEGIN TO PUSH DRIER AIR INTO PENNSYLVANIA LATER
THIS AFTERNOON INTO EARLY SATURDAY. THE COLD FRONT WILL LIKELY
TRIGGER THUNDERSTORMS LATER TODAY. MUCH DRIER WILL MOVE OVER THE
ENTIRE REGION SATURDAY. A TROUGH BUILDS OVER NORTHEASTERN NORTH
AMERICA WHICH SHOULD KEEP US IN GENERALLY NORTHWEST FLOW MOST OF
THE NEXT 3-8 DAYS ENSURING WEAK FRONTAL PASSAGES AND GENERALLY LOW
HUMIDITY AND LOW PROBABILITY OF SIGNIFICANT RAINFALL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR CONTINUES TO SHOW SHOWERS AND EMBEDDED THUNDERSTORMS MOVING
OVER THE MOISTURE BOUNDARY OVER CENTRAL PENNSYLVANIA BEST DEFINED
IN THE LOW-LEVEL THETA-E GRADIENT. THE LARGER SCALE THETA GRADIENT
IS IMPLYING THE FRONTAL PUSH TO OUR NORTHWEST IS NOT INTO
NORTHWESTERNMOST PA. SHOWERS WILL BECOME MORE NUMEROUS IN THE WEST
OVER THE NEXT FEW HOURS.
THE WARM MOIST AIR AND ABOVE NORMAL PW HAVE KEPT THE MORNING LOWS
MAINLY IN THE UPPER 60S AND 70S. GOING TO BE A WARM MOIST DAY OVER
CENTRAL AND SOUTHEASTERN AREAS.
THE PROBABILITY OF RAIN SHOULD DROP OFF FAST IN THE NW THIS
AFTERNOON. MOST FORECASTS FROM SREF TO HRRR IMPLY BY MID- LATE
AFTERNOON THE THREAT OF RAIN IN NW PASSES. EVEN CENTRAL AREAS
NOW APPEAR TO HAVE A GOOD SHOW OF NICE LATER AFTERNOON AND EARLY
EVENING AS THE DRIER AIR SLIDES TO THE SOUTHEAST.
SHOWERS AND STORMS WITH LOCALLY HEAVY RAIN FROM A FEW STRONGER
CELLS WILL LINGER LONGER IN THE SOUTHEAST.
TEMPS MAINLY 70S IN NEW TO MID-UPPER 80S SOUTHEAST. WINDS SHOULD
BECOME MORE WESTERLY IN NW PA THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE MODELS ALL SHOW LOWER PW AIR FILTERING INTO PA FAST. DROPPED
ALL POPS IN CENTRAL AND NORTHERN AREAS BEFORE 8 PM. LOWERED POPS
FAST IN THE SOUTHEAST WITH NO RAIN OF NOTE MUCH AFTER MIDNIGHT
THEN THE DRYING OUT BEGINS. ENSEMBLES IMPLY BY 0300 UTC ALL THREAT
OF RAIN IS TO OUR SOUTH AND EAST.
SATURDAY SHOULD BE MOSTLY SUNNY WITH TEMPERATURES NEAR NORMAL. THE
850 HPA TEMPS DO NOT DROP BELOW NORMAL UNTIL AFTER THIS PERIOD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE COMING WEEK SHOULD BE RELATIVELY DRY AS MOST MODELS AT THIS
TIME AND ENSEMBLE FORECAST SYSTEMS (EFS) SHOW PW VALUES GENERALLY
NORMAL TO BELOW NORMAL. NOT A GOOD PATTERN FOR RAIN LET ALONE
HEAVY RAINFALL.
A MEAN TROUGH WILL DOMINATE THE EASTERN UNITED STATES WELL INTO
NEXT WEEK. SOME PIN WHEELING WAVES IMPLY CHANCES OF SCATTERED
SHOWERS SHOULD WE GET A ENOUGH MOISTURE OR INSTABILITY AHEAD OF
SOME OF THE WAVES. AT THIS TIME WE FLIRT WITH SOME MOISTURE TUES-WED
FOR SLIGHT INCREASE SHOWERS...NOT VERY IMPRESSIVE.
THE 850 HPA TEMPS ARE NORMAL TO SOME PERIODS WHERE THEY FALL
SLIGHTLY BELOW NORMAL. THE PW STAYS NORMAL TO BELOW NORMAL TOO.
THE PIN WHEELING TROUGHS OF COURSE PUSH THE WEAK SURGES OF COOLER
AND DRIER AIR IN.
THUS A GENERALLY COOL DRY WEEK IS CURRENTLY FORECAST.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
A FEW SHOWERS ON THE RADAR...MAINLY SE...WHERE WINDS ARE
MORE FROM THE SE.
WIDE RANGE WITH CIGS WILL CONTINUE THIS MORNING. VISIBILITIES
NOT BAD FOR THE MOST PART.
EXPECT CONDITIONS TO IMPROVE FROM WEST TO EAST THIS AFT...
AS WEAK COLD FRONT MOVES ACROSS THE AREA. DEWPOINTS ON
THE HIGH SIDE...BUT WINDS ALOFT NOT REAL STRONG FOR
SEVERE STORMS.
EXPECT SHOWERS AND STORMS TO TAPER OFF ACROSS THE FAR
SE ON SAT.
WEAK COLD ADVECTION TODAY INTO SAT...NOT A LOT OF COLD
ADVECTION BEFORE THE MIDDLE OF NEXT WEEK.
MAIN CONCERN WILL BE IF WE WILL GET FOG SAT AM...BEHIND
THE FRONT...AS TEMPS FALL TO NEAR THE CROSS OVER VALUE.
LOOKS LIKE IT WILL BE MID WEEK...BEFORE ANY REAL DEEP
COLD AIR WORKS INTO CENTRAL PA.
OUTLOOK...
SAT...MVFR/IFR EARLY WITH PATCHY FOG...THEN VFR.
SUN-MON...GENERALLY VFR...BUT POSSIBLE AM RESTRICTIONS IN FOG.
TUE...VFR...BUT POSSIBLE RESTRICTIONS IN SHRA/TSRA WITH NEXT
COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1113 AM EDT FRI AUG 9 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE REGION THROUGH SATURDAY.
A COLD FRONT WILL MOVE SLOWLY SOUTH INTO THE AREA LATE THIS WEEKEND.
A SECOND COLD FRONT IS EXPECTED TO MOVE OVER THE REGION DURING THE
MID WEEK. DEEP MOISTURE MAY LINGER OVER THE SOUTHERN APPALACHIAN
REGION UNTIL NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM EDT...WILL DELAY THE ONSET OF ANY SCT TSTM COVERAGE
EAST OF THE MTNS UNTIL LATER IN THE AFTN GIVEN THE LACK OF
TRIGGERING AND LATEST HRRR MODEL CONVECTIVE TIMING. WILL PUSH UP THE
TIMING AND VALUE OF POPS IN THE WRN MTNS GIVEN MORE WESTERLY UPSLOPE
TRIGGERING AND LATEST HRRR AND RADAR TRENDS. MAX TEMPS HAVE ALSO
BEEN RAISED AT LEAST A DEGREE THROUGHOUT MOST OF THE AREA GIVEN THE
BETTER ISOLATION THAN YESTERDAY. FAR ERN PIEDMONT SECTIONS WILL SEE
HEAT INDEX VALUES CREEP POSSIBLY INTO THE UPPER 90S TODAY WITH NEAR
90 MAX TEMPS AND DEWPOINTS IN THE MID 70S...BUT THESE SHOULD REMAIN
WELL BELOW ADVISORY LEVELS.
OTHERWISE...DEEP SW FLOW WILL MAINTAIN UNSEASONABLY HIGH MOISTURE
LEVELS WITH PWAT VALUES IN THE NEIGHBORHOOD OF 2 INCHES OVER THE
AREA THROUGH THE PERIOD. WITH CLOUD BEARING WINDS ONLY AROUND 10
KTS...SLOW CELL MOVEMENT COMBINED WITH EFFICIENT RAINFALL PRODUCERS
WILL RESULT IN A LOCALIZED FLASH FLOOD THREAT...ESPECIALLY WITH ANY
CELLS THAT BECOME ANCHORED ON TERRAIN FEATURES OR OUTFLOW
BOUNDARIES.
MUCH LIKE LAST EVENING...MOST OF THE SHORT TERM AND MESOSCALE MODELS
FEATURE A RATHER ABRUPT CESSATION TO CONVECTIVE ACTIVITY THIS
EVENING...SO POPS WILL DIMINISH INTO THE OVERNIGHT HOURS...ALTHOUGH
THE APPROACH OF A FRONTAL BOUNDARY FROM THE TN VALLEY WILL
INCREASE THE CHANCES FOR CONVECTION TO WANDER INTO THE NC MTNS LATE
TONIGHT INTO EARLY SATURDAY...SO A CHANCE POP WILL BE CARRIED THERE
THROUGH THE OVERNIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 200 AM EDT FRIDAY...ON SATURDAY...BOTH THE GFS AND ECMWF
INDICATE THAT A WEST TO EAST BACK DOOR COLD FRONT WILL DRIFT SOUTH
ACROSS KY/VA. THE FORECAST AREA WILL REMAIN SOUTH OF THE
BOUNDARY...RESULTING IN LIGHT LLVL SOUTHWEST WINDS. GFS FORECAST
SOUNDINGS INDICATE THAT THE ENVIRONMENT ACROSS THE CWA WILL LIKELY
FEATURE PW VALUES IN EXCESS OF 2 INCHES...K INDEX VALUES IN THE
U30S...AND A DEEP LAYER OF RH VALUES GREATER THAN 80 PERCENT. IN
ADDITION...CAPE VALUES WILL LIKELY RANGE BETWEEN 1500-2000 J/KG
WITH WEAK LLVL CIN. MODELS INDICATE THAT A MID LEVEL RIDGE WILL
REMAIN CENTERED OFF THE GA COAST...RIDGING WEST INTO THE SOUTHERN
PLAINS. THE PATTERN WILL LIKELY FEATURE MODERATE H5 HEIGHTS OVER THE
UPPER SAVANNAH RIVER VALLEY...FAVORING THE NRN CWA FOR PASSAGES OF
POTENTIAL S/W. THE COMBINATION OF THE MOISTURE RICH
ENVIRONMENT...ADEQUATE CONDITIONAL INSTABILITY...AND THE PLACEMENT
OF THE SFC FRONT AND MID LEVEL S/W...I WILL CONTINUE TO INDICATE
LIKELY POPS ACROSS THE MTNS AND I-40 CORRIDOR...WITH SOLID CHC POPS
SOUTH.
GFS FORECAST SOUNDINGS INDICATE THAT THE MOIST ENVIRONMENT WILL
REMAIN THROUGH SUNDAY. SHORT RANGE MODELS INDICATE THAT THE SFC
FRONT WILL SLIP SLIGHTLY FURTHER SOUTH...POSSIBLY ENTERING THE I-40
CORRIDOR. THE MID LEVEL PATTERN WILL ONCE AGAIN FAVOR THE TRACK OF
ANY WEAK EMBEDDED S/W ACROSS THE NORTHERN HALF OF THE
CWA...ESPECIALLY DURING THE AFTERNOON. I WILL CONTINUE TO ADVERTISE
LIKELY POPS...BUT WILL INCREASE POPS ACROSS THE UPPER SAVANNAH RIVER
VALLEY FROM SATURDAY. THE MAIN THREAT OVER THE WEEKEND WILL BE THE
POTENTIAL FOR EXCESSIVE RAINFALL. HIGH TEMPERATURES WILL REMAIN
SLIGHTLY BELOW NORMAL THROUGH THE WEEKEND.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 220 AM EDT FRIDAY...THE EXTENDED PERIOD CONTINUES TO APPEAR
UNSETTLED. THE WEEKEND COLD FRONT MAY BECOME NEARLY STATIONARY OVER
THE CENTRAL CAROLINAS ON MONDAY...THEN PUSHING ACROSS THE LOW
COUNTRY ON TUESDAY. HOWEVER...CANADIAN HIGH PRESSURE WILL BUILD
ACROSS THE GREAT LAKES ON TUESDAY...POSSIBLY SWEEPING ANOTHER WEAK
BACK DOOR FRONT INTO THE FA TUESDAY NIGHT INTO WEDNESDAY. IT APPEARS
THAT WEDNESDAY AND WEDNESDAY NIGHT WILL BE FAVORABLE FOR SHRA/TSRA
DEVELOPMENT...GIVEN THE POSSIBLE PASSAGE OF A MID LEVEL TROF
COMBINED WITH FROPA/ISENTROPIC LIFT ACROSS THE SOUTHERN APPALACHIAN
REGION. I WILL INDICATE POPS BETWEEN 40 TO 50 PERCENT WEDNESDAY AND
WEDNESDAY NIGHT. DRIER AIR WILL BEGIN TO BUILD FROM THE NW DURING
THE DAY ON THURSDAY...BUT MOISTURE APPEARS TO REMAIN EAST OF THE
MTNS. I WILL INDICATE LOWERING POPS ON THURSDAY. OVERALL...THE
EXTENDED PERIOD APPEARS PRIMED FOR PERIODS OF HEAVY RAINFALL.
TEMPERATURES WILL VERY LIKELY VERIFY BELOW NORMAL THROUGH THE
PERIOD.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...STILL ANTICIPATE FURTHER DEVELOPMENT OF
CUMULUS/STRATOCUMULS MVFR LEVEL SCT TO BKN CLOUDS WITH HEATING INTO
THE EARLY AFTN. SCATTERED CONVECTION IS ALSO EXPECTED TO DEVELOP
ACROSS MUCH OF THE AREA THIS AFTERNOON/EVENING. KAVL WILL BE THE
MOST LIKELY TERMINAL TO SEE CONVECTION...AS THE HIGH TERRAIN TO THE
SOUTHWEST APPEARS TO BE A FAVORED LOCATION FOR DEVELOPMENT THIS
AFTERNOON. CONVECTION IS EXPECTED TO GRADUALLY WANE TONIGHT...
ALTHOUGH CHANCES MAY INCREASE LATE TONIGHT ACROSS THE MOUNTAINS...AS
CONVECTION AHEAD OF A COLD FRONT INCHES ITS WAY ACROSS THE TN
VALLEY. WINDS WILL REMAIN OUT OF THE SW AT 7 TO 10 KTS. NOCTURNAL
FOG/STRATUS WILL BE POSSIBLE...BUT OCCURRENCE MAY DEPEND HEAVILY
UPON WHAT SITES RECEIVE RAINFALL LATER TODAY.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM ACTIVITY WILL CONTINUE
THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS WILL BE POSSIBLE LATE
EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS UNDER
ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY NEXT
WEEK.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 88% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 88% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 83% HIGH 98% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...NED
NEAR TERM...HG/JDL
SHORT TERM...NED
LONG TERM...NED
AVIATION...HG/JDL
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
921 PM CDT SAT AUG 10 2013
.UPDATE...
AN AREA OF SHOWERS AND THUNDERSTORMS NOW APPROACHING THE
NORTHWESTERN CWA...AND ACCORDING TO THE HRRR MODEL...LOOKS TO
TRACK ACROSS MUCH OF THE WESTERN CWA DURING THE OVERNIGHT HOURS.
MAY STILL SEE A FEW SHOWERS OR STORMS POP UP ACROSS THE FAR
SOUTHEAST AS WELL AS THE LLJ KICKS IN OVERNIGHT. HAVE ADJUSTED
POPS AND WEATHER ACCORDINGLY. NO CHANGES MADE TO WINDS OR
TEMPERATURES AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
A WEAK WEATHER SYSTEM IS PROCEEDING THROUGH THE CWA...WITH
GENERALLY LIGHT RAIN...AND THE ODD LIGHTNING STRIKE. THIS SYSTEM
WILL CONTINUE EAST...WITH THE NORTHERN END OF THE PRECIPITATION
ENCOUNTERING DRIER AIR AND THUS WILL SEE LOWER POPS ALONG AND
NORTH OF HIGHWAY 12. ANOTHER CLIPPER IS EVIDENT OVER NORTHERN
NORTH DAKOTA. GUIDANCE HAS PEGGED THIS SYSTEM TO MOVE THROUGH
NORTHEAST SOUTH DAKOTA WITH ADDITIONAL LIGHT QPF. A LOW LEVEL JET
DEVELOPS IN RESPONSE TO THESE FEATURES...HOWEVER A BOUNDARY HAS
SET UP BETWEEN VALENTINE AND ONEIL NEBRASKA...WHICH WILL HELP
FOCUS CONVECTION AND LIMIT STORMS FROM DEVELOPING AS FAR NORTH AS
THE EASTERN CWA. HIGH PRESSURE FOLLOWS FOR SUNDAY...REINFORCING
EASTERLY FLOW...AND FORCING LOW LEVEL MOISTURE AND INSTABILITY TO
THE WEST. STORMS FIRING IN WESTERN SOUTH DAKOTA MAY TREK INTO FAR
WESTERN COUNTIES BEFORE DISSIPATING HOWEVER. UNDER WEST/NORTHWEST
FLOW ALOFT...WE MAY SEE ADDITIONAL WEAK IMPULSES WHICH MODELS HAVE
A HARD TIME CAPTURING...THOUGH AT THIS TIME NONE LOOK TO HAVE ANY
MOISTURE BELOW 15KFT TO BE CONCERNED WITH.
H85 TEMPERATURES WILL RANGE FROM +12 TO +16C...SLIGHTLY BELOW
NORMAL BUT NOT CLIMATOLOGICALLY SIGNIFICANT...THUS WILL KEEP
TEMPERATURE FORECAST A TAD BELOW NORMALS.
.LONG TERM...TUESDAY THROUGH SATURDAY
THE LATEST SUITE OF MODELS CONTINUE TO ADVERTISE THE SAME OLD
PATTERN THAT HAS BEEN LOCKED IN NOW FOR SOMETIME ACROSS THE CONUS.
THAT PATTERN BEING MID LEVEL RIDGING OVER THE ROCKIES...AND
TROFFING OVER THE EASTERN CONUS. MEANWHILE SFC HIGH PRESSURE WILL
CONTINUE TO FEED DRY AIR INTO THE EASTERN CWA...AND ALSO SERVE TO
KEEP THE MOST ACTIVE BAROCLINIC ZONE/BOUNDARY PUSHED WEST AND
SOUTH OF THE ABR FORECAST AREA. SO THROUGH THE ENTIRE PERIOD IT
APPEARS THE SOUTHWEST CWA WILL HAVE THE HIGHEST PROBABILITIES FOR
MEASURABLE RAIN SINCE IT WILL BE CLOSEST TO THE NEARLY STATIONARY
SFC BOUNDARY. TEMPERATURES SHOULD AVERAGE OUT NEAR OR BELOW NORMAL
UNTIL TOWARD NEXT WEEKEND. AT THAT TIME THE PATTERN IS EXPECTED TO
SHIFT A LITTLE EAST AND ALLOW FOR A WARM AIR INTRUSION.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
SCATTERED LIGHT SHOWERS WILL PUSH ACROSS THE SOUTHEASTERN CWA
DURING THE EARLY EVENING HOURS. A FEW THUNDERSTORMS ARE POSSIBLE
ACROSS THE SOUTH CENTRAL CWA...THEN AGAIN AROUND AND SHORTLY AFTER
MIDNIGHT ACROSS ABOUT THE SOUTHERN HALF OF THE CWA...POSSIBLY
AFFECTING KATY AND KPIR. BY SUNRISE SUNDAY MORNING...THE
PRECIPITATION SHOULD COME TO AN END...LEAVING VFR CONDITIONS IN
CONTROL THROUGH THE DAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...PARKIN
SHORT TERM...CONNELLY
LONG TERM...TDK
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
933 PM CDT SAT AUG 10 2013
.UPDATE...
UPDATED FOR INCREASING RAIN CHANCES IN NARROW ZONE ALONG THE
MS/TN BORDER.
&&
.DISCUSSION...
OUTFLOW FROM EARLIER CONVECTION IN NORTHEAST MISSISSIPPI HAS
DRIFTED NORTH TO ALONG A TUNICA...OLIVE BRANCH...SELMER...SAVANNAH
LINE...WITH CONVECTION BACKBUILDING INTO HARDEMAN COUNTY. RAINFALL
AMOUNTS WITH THESE TRAINING ECHOES HAVE BEEN UP TO OVER
THREE INCHES...PROMPTING FLASH FLOOD WARNINGS. STORMS SHOULD
CONTINUE IN THIS CORRIDOR THROUGH MIDNIGHT.
JAB
&&
.PREV DISCUSSION... /ISSUED 738 PM CDT SAT AUG 10 2013/
UPDATE...
UPDATED TO REDUCE RAIN CHANCES THIS EVENING AND ADJUST CLOUD COVER.
DISCUSSION...
LOCATION OF WEAK FRONTAL BOUNDARY BECOMING MORE DIFFUSE AS
MEMPHIS WINDS HAVE NOW SWUNG NORTHERLY. MAIN FRONTAL CLOUD COVER
THOUGH REMAINS NORTH OF A HARRISBURG ARKANSAS TO HUNTINGDON
TENNESSEE LINE. ALSO RADAR TRENDS HAVE SHOWN A FEW SPOTTY SHOWERS
IN THIS ZONE OVER THE PAST HOUR.
THE COMBINATION OF DIMINISHING INSTABILITY AND THE HRRR MODEL
TRENDING TOWARDS WEAKENING CONVECTION IN CENTRAL ARKANSAS...HAVE
REDUCED RAIN CHANCES TO JUST SLIGHT THROUGH THE EVENING. HAVE
LEFT FORECAST FOR AFTER MIDNIGHT ALONE ALONG AND NORTH OF
INTERSTATE FORTY...AS PERSISTENCE THE PAST FEW DAYS HAS SHOWN
SHOWERS AND STORMS REFIRING IN THIS REGION BEFORE DAYBREAK.
FURTHER SOUTH HAVE KEPT THE SLIGHT RAIN CHANCE WORDING THROUGH
EARLY SUNDAY MORNING.
ALSO TWEAKED CLOUD COVER WORDING TO MOSTLY CLOUDY SKIES ACROSS
THE NORTHWEST THROUGH THE NIGHT.
JAB
PREV DISCUSSION... /ISSUED 730 PM CDT SAT AUG 10 2013/
UPDATE...
UPDATED FOR THE 00Z AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 345 PM CDT SAT AUG 10 2013/
DISCUSSION...20Z SURFACE ANALYSIS PLACES A QUASI-STATIONARY
BOUNDARY FROM THE OHIO VALLEY BACK THROUGH THE MISSOURI
BOOTHEEL...CENTRAL ARKANSAS...AND INTO EAST TEXAS THIS AFTERNOON.
SHOWERS AND A FEW THUNDERSTORMS HAVE MAINLY BEEN CONFINED TO NORTH
MISSISSIPPI THIS AFTERNOON WHERE A COMBINATION OF MODERATE
INSTABILITY...LEFT OVER OUTFLOW BOUNDARIES FROM LAST NIGHT/S
CONVECTION...AND A TROPICAL PLUME OF LOW LEVEL MOISTURE FROM THE
GULF OF MEXICO RESULTED IN SHOWERS AND THUNDERSTORMS AS CONVECTIVE
TEMPERATURES WERE REACHED. MEANWHILE...THE BOUNDARY LAYER
STABILIZED ACROSS THE REMAINDER OF THE MID SOUTH AND
SHOWERS/THUNDERSTORMS DISSIPATED. SHORT TERM CONVECTIVE POTENTIAL
THROUGH TUESDAY NIGHT REMAINS THE PREDOMINANT FORECAST CHALLENGE
IN THIS AFTERNOON/S FORECAST.
SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)...LATEST SHORT TERM
MODELS CONTINUE TO INDICATE VERY LITTLE IF ANY CHANGE IN THE
OVERALL PATTERN ACROSS THE LOWER MISSISSIPPI VALLEY AS A QUASI-
STATIONARY WILL NOT MOVE MUCH ACROSS THE MIDDLE AND LOWER MISSISSIPPI
VALLEYS THROUGH TUESDAY NIGHT. THE TREND OVER THE PAST FEW NIGHTS
HAS BEEN FOR THE RE-DEVELOPMENT OF SHOWERS AND THUNDERSTORMS AS
850 MB LOW LEVEL WINDS INCREASE TO 25-30 KTS ALONG AN 850 MB
THETA-E RIDGE AXIS AND MIGRATE INTO THE MID SOUTH OVERNIGHT
TOWARDS MORNING. THUS...HAVE LEANED TOWARD LOWER EVENING
SHOWER/THUNDERSTORM CHANCES WITH GREATER CHANCES
OVERNIGHT...ESPECIALLY ALONG AND NORTHWEST OF THE MISSISSIPPI
RIVER. LATEST MODELS DO NOT INDICATE A SUBSTANTIAL AMOUNT OF RAIN
OCCURRING OVER THE NEXT FEW DAYS ALONG WITH A MORE FAVORABLE
WIDESPREAD HEAVY RAINFALL PATTERN. THUS...DECIDED TO NOT ISSUE A
FLASH FLOOD WATCH GIVEN THESE RECENT TRENDS. NONETHELESS...LATER
SHIFTS WILL CONTINUE TO MONITOR SUBSEQUENT TRENDS/MODEL RUNS IF
THIS SCENARIO CHANGES. REGARDLESS...HIGH PRECIPITABLE WATER VALUES
AVERAGING AROUND 2 INCHES WILL STILL FAVOR THE POTENTIAL FOR
LOCALIZED FLASH FLOODING FROM HEAVY RAINFALL. WILL MENTION THE
POTENTIAL FOR A STRONG THUNDERSTORM OR TWO WITH GUSTY WINDS AND
HEAVY RAINFALL AS THE THREATS.
LONG TERM...(WEDNESDAY THROUGH SATURDAY)...LATEST GFS/ECMWF LONG
TERM MODELS INDICATE THE THREAT FOR PERSISTENT SHOWERS AND
THUNDERSTORMS WILL GRADUALLY DIMINISH BY LATE WEEK AS AN UPPER
LEVEL LONGWAVE TROUGH AXIS PUSHES THE WEAK QUASI-STATIONARY
BOUNDARY SOUTH AS A COLD FRONT. SLIGHTLY COOLER TEMPERATURES WILL
BUILD IN FOR THE REMAINDER OF THE PERIOD.
CJC
&&
.AVIATION...
00Z TAF CYCLE
A FRONTAL BOUNDARY REMAINS STRETCHED ALONG OR JUST NORTH OF THE
I-40 CORRIDOR. ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO THE
NORTH OF THE FRONT AND MAY IMPACT KJBR THROUGH THE EVENING. IN
ADDITION...MVFR CIGS WILL BE COMMON TO THE NORTH OF THE FRONT
INCLUDING KJBR. A CONVECTIVE OUTFLOW BOUNDARY MOVING NORTH FROM
NORTHEAST MISSISSIPPI INTO WEST TENNESSEE MAY RESULT IN A FEW
STORMS IN THE VICINITY OF KMKL OVER THE NEXT FEW HOURS.
ELSEWHERE...AT KMEM AND KTUP EXPECT DRY CONDITIONS AND VFR CIGS/VSBYS.
LATER TONIGHT...INCREASING LOW LEVEL FLOW NOSING OVER THE FRONT
WILL LIKELY RESULT IN INCREASING STORM COVERAGE ALONG AND NORTH OF
THE FRONT. THE FRONT WILL LIKELY MOVE VERY LITTLE THROUGH THE
NIGHT. EXPECT AN INCREASE IN STORMS AT KJBR LATE TONIGHT INTO
SUNDAY MORNING ALONG WITH IFR CIG REDUCTIONS. ADDED A TEMPO TO
ACCOUNT FOR THIS ACTIVITY. FURTHER SOUTH...OUTFLOW DRIVEN
CONVECTION MAY RESULT IN SCATTERED SHOWERS AND STORMS DEVELOPING
SOUTH INTO KMKL AND KMEM THROUGH SUNDAY MORNING.
LATER SUNDAY AFTERNOON...CONVECTIVE OUTFLOW FROM MORNING
CONVECTION SHOULD SPREAD SOUTH WITH AN OUTFLOW DOMINATED AIRMASS
DEVELOPING AT KMEM/KJBR/KMKL WITH SCATTERING CLOUDS AND REDUCED
STORM CHANCES. INCREASED DIURNAL CONVECTION WILL AGAIN DEVELOP AT
KTUP BY AFTERNOON AND WENT WITH TEMPO DURING THE AFTERNOON TO
ACCOUNT FOR THIS ACTIVITY. THESE STORMS SHOULD DEVELOP WITHIN DEEP
TROPICAL MOISTURE PLUME STILL IN PLACE OVER NORTHEAST MISSISSIPPI.
WINDS WILL BE LIGHT NORTHERLY TO THE NORTH OF ANY OUTFLOW BOUNDARY AND
LIGHT AND VARIABLE TO THE SOUTH. WINDS WILL RETURN LIGHT SOUTHERLY
LATER SUNDAY AFTERNOON AT KMEM AND KMKL AS THE AIRMASS RECOVERS.
JLH
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 75 91 74 91 / 30 50 30 50
MKL 69 87 71 87 / 30 50 30 50
JBR 71 87 72 88 / 50 50 30 50
TUP 73 91 72 91 / 20 50 30 50
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
738 PM CDT SAT AUG 10 2013
.UPDATE...
UPDATED TO REDUCE RAIN CHANCES THIS EVENING AND ADJUST CLOUD COVER.
&&
.DISCUSSION...
LOCATION OF WEAK FRONTAL BOUNDARY BECOMING MORE DIFFUSE AS
MEMPHIS WINDS HAVE NOW SWUNG NORTHERLY. MAIN FRONTAL CLOUD COVER
THOUGH REMAINS NORTH OF A HARRISBURG ARKANSAS TO HUNTINGDON
TENNESSEE LINE. ALSO RADAR TRENDS HAVE SHOWN A FEW SPOTTY SHOWERS
IN THIS ZONE OVER THE PAST HOUR.
THE COMBINATION OF DIMINISHING INSTABILITY AND THE HRRR MODEL
TRENDING TOWARDS WEAKENING CONVECTION IN CENTRAL ARKANSAS...HAVE
REDUCED RAIN CHANCES TO JUST SLIGHT THROUGH THE EVENING. HAVE
LEFT FORECAST FOR AFTER MIDNIGHT ALONE ALONG AND NORTH OF
INTERSTATE FORTY...AS PERSISTENCE THE PAST FEW DAYS HAS SHOWN
SHOWERS AND STORMS REFIRING IN THIS REGION BEFORE DAYBREAK.
FURTHER SOUTH HAVE KEPT THE SLIGHT RAIN CHANCE WORDING THROUGH
EARLY SUNDAY MORNING.
ALSO TWEAKED CLOUD COVER WORDING TO MOSTLY CLOUDY SKIES ACROSS
THE NORTHWEST THROUGH THE NIGHT.
JAB
&&
.PREV DISCUSSION... /ISSUED 730 PM CDT SAT AUG 10 2013/
.UPDATE...
.UPDATED FOR THE 00Z AVIATION DISCUSSION.
.PREV DISCUSSION... /ISSUED 345 PM CDT SAT AUG 10 2013/
DISCUSSION...20Z SURFACE ANALYSIS PLACES A QUASI-STATIONARY
BOUNDARY FROM THE OHIO VALLEY BACK THROUGH THE MISSOURI
BOOTHEEL...CENTRAL ARKANSAS...AND INTO EAST TEXAS THIS AFTERNOON.
SHOWERS AND A FEW THUNDERSTORMS HAVE MAINLY BEEN CONFINED TO NORTH
MISSISSIPPI THIS AFTERNOON WHERE A COMBINATION OF MODERATE
INSTABILITY...LEFT OVER OUTFLOW BOUNDARIES FROM LAST NIGHT/S
CONVECTION...AND A TROPICAL PLUME OF LOW LEVEL MOISTURE FROM THE
GULF OF MEXICO RESULTED IN SHOWERS AND THUNDERSTORMS AS CONVECTIVE
TEMPERATURES WERE REACHED. MEANWHILE...THE BOUNDARY LAYER
STABILIZED ACROSS THE REMAINDER OF THE MID SOUTH AND
SHOWERS/THUNDERSTORMS DISSIPATED. SHORT TERM CONVECTIVE POTENTIAL
THROUGH TUESDAY NIGHT REMAINS THE PREDOMINANT FORECAST CHALLENGE
IN THIS AFTERNOON/S FORECAST.
SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)...LATEST SHORT TERM
MODELS CONTINUE TO INDICATE VERY LITTLE IF ANY CHANGE IN THE
OVERALL PATTERN ACROSS THE LOWER MISSISSIPPI VALLEY AS A QUASI-
STATIONARY WILL NOT MOVE MUCH ACROSS THE MIDDLE AND LOWER MISSISSIPPI
VALLEYS THROUGH TUESDAY NIGHT. THE TREND OVER THE PAST FEW NIGHTS
HAS BEEN FOR THE RE-DEVELOPMENT OF SHOWERS AND THUNDERSTORMS AS
850 MB LOW LEVEL WINDS INCREASE TO 25-30 KTS ALONG AN 850 MB
THETA-E RIDGE AXIS AND MIGRATE INTO THE MID SOUTH OVERNIGHT
TOWARDS MORNING. THUS...HAVE LEANED TOWARD LOWER EVENING
SHOWER/THUNDERSTORM CHANCES WITH GREATER CHANCES
OVERNIGHT...ESPECIALLY ALONG AND NORTHWEST OF THE MISSISSIPPI
RIVER. LATEST MODELS DO NOT INDICATE A SUBSTANTIAL AMOUNT OF RAIN
OCCURRING OVER THE NEXT FEW DAYS ALONG WITH A MORE FAVORABLE
WIDESPREAD HEAVY RAINFALL PATTERN. THUS...DECIDED TO NOT ISSUE A
FLASH FLOOD WATCH GIVEN THESE RECENT TRENDS. NONETHELESS...LATER
SHIFTS WILL CONTINUE TO MONITOR SUBSEQUENT TRENDS/MODEL RUNS IF
THIS SCENARIO CHANGES. REGARDLESS...HIGH PRECIPITABLE WATER VALUES
AVERAGING AROUND 2 INCHES WILL STILL FAVOR THE POTENTIAL FOR
LOCALIZED FLASH FLOODING FROM HEAVY RAINFALL. WILL MENTION THE
POTENTIAL FOR A STRONG THUNDERSTORM OR TWO WITH GUSTY WINDS AND
HEAVY RAINFALL AS THE THREATS.
LONG TERM...(WEDNESDAY THROUGH SATURDAY)...LATEST GFS/ECMWF LONG
TERM MODELS INDICATE THE THREAT FOR PERSISTENT SHOWERS AND
THUNDERSTORMS WILL GRADUALLY DIMINISH BY LATE WEEK AS AN UPPER
LEVEL LONGWAVE TROUGH AXIS PUSHES THE WEAK QUASI-STATIONARY
BOUNDARY SOUTH AS A COLD FRONT. SLIGHTLY COOLER TEMPERATURES WILL
BUILD IN FOR THE REMAINDER OF THE PERIOD.
CJC
&&
.AVIATION...
00Z TAF CYCLE
A FRONTAL BOUNDARY REMAINS STRETCHED ALONG OR JUST NORTH OF THE
I-40 CORRIDOR. ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO THE
NORTH OF THE FRONT AND MAY IMPACT KJBR THROUGH THE EVENING. IN
ADDITION...MVFR CIGS WILL BE COMMON TO THE NORTH OF THE FRONT
INCLUDING KJBR. A CONVECTIVE OUTFLOW BOUNDARY MOVING NORTH FROM
NORTHEAST MISSISSIPPI INTO WEST TENNESSEE MAY RESULT IN A FEW
STORMS IN THE VICINITY OF KMKL OVER THE NEXT FEW HOURS.
ELSEWHERE...AT KMEM AND KTUP EXPECT DRY CONDITIONS AND VFR CIGS/VSBYS.
LATER TONIGHT...INCREASING LOW LEVEL FLOW NOSING OVER THE FRONT
WILL LIKELY RESULT IN INCREASING STORM COVERAGE ALONG AND NORTH OF
THE FRONT. THE FRONT WILL LIKELY MOVE VERY LITTLE THROUGH THE
NIGHT. EXPECT AN INCREASE IN STORMS AT KJBR LATE TONIGHT INTO
SUNDAY MORNING ALONG WITH IFR CIG REDUCTIONS. ADDED A TEMPO TO
ACCOUNT FOR THIS ACTIVITY. FURTHER SOUTH...OUTFLOW DRIVEN
CONVECTION MAY RESULT IN SCATTERED SHOWERS AND STORMS DEVELOPING
SOUTH INTO KMKL AND KMEM THROUGH SUNDAY MORNING.
LATER SUNDAY AFTERNOON...CONVECTIVE OUTFLOW FROM MORNING
CONVECTION SHOULD SPREAD SOUTH WITH AN OUTFLOW DOMINATED AIRMASS
DEVELOPING AT KMEM/KJBR/KMKL WITH SCATTERING CLOUDS AND REDUCED
STORM CHANCES. INCREASED DIURNAL CONVECTION WILL AGAIN DEVELOP AT
KTUP BY AFTERNOON AND WENT WITH TEMPO DURING THE AFTERNOON TO
ACCOUNT FOR THIS ACTIVITY. THESE STORMS SHOULD DEVELOP WITHIN DEEP
TROPICAL MOISTURE PLUME STILL IN PLACE OVER NORTHEAST MISSISSIPPI.
WINDS WILL BE LIGHT NORTHERLY TO THE NORTH OF ANY OUTFLOW BOUNDARY AND
LIGHT AND VARIABLE TO THE SOUTH. WINDS WILL RETURN LIGHT SOUTHERLY
LATER SUNDAY AFTERNOON AT KMEM AND KMKL AS THE AIRMASS RECOVERS.
JLH
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 75 91 74 91 / 30 50 30 50
MKL 69 87 71 87 / 30 50 30 50
JBR 71 87 72 88 / 50 50 30 50
TUP 73 91 72 91 / 20 50 30 50
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
157 PM CDT FRI AUG 9 2013
.MESOSCALE UPDATE...TO INCLUDE SURFACE BASED CAPES
MESO CONVECTIVE VORTICITY CENTER APPROACHING POPLAR BLUFF AT THIS
TIME. MCV KICKED OFF WHAT APPEARS TO BE A GRAVITY WAVE THAT HAS
JUST CROSSED MISSISSIPPI RIVER. WINDS TURNED WEST AT MEMPHIS WITH
ITS PASSAGE. THIS FEATURE WILL NEED TO BE WATCHED AS IT APPROACHES
THE TENNESSEE RIVER AND MOVES EASTWARD. GRAVITY WAVES CAN IGNITE
STORMS AND INTENSIFY THEM QUICKLY. SURFACE BASED CAPES ARE 4000
PLUS JOULES PER KILOGRAM FROM NORTHEAST MISSISSIPPI NORTHEAST TO
AB OUT NASHVILLE.
BOYD
&&
.PREV DISCUSSION... /ISSUED 154 PM CDT FRI AUG 9 2013/
MESOSCALE UPDATE...
MESO CONVECTIVE VORTICITY CENTER APPROACHING POPLAR BLUFF AT THIS
TIME. MCV KICKED OFF WHAT APPEARS TO BE A GRAVITY WAVE THAT HAS
JUST CROSSED MISSISSIPPI RIVER. WINDS TURNED WEST AT MEMPHIS WITH
ITS PASSAGE. THIS FEATURE WILL NEED TO BE WATCHED AS IT APPROACHES THE
TENNESSEE RIVER AND MOVES EASTWARD. GRAVITY WAVES CAN IGNITE
STORMS AND INTENSIFY THEM QUICKLY.
BOYD
PREV DISCUSSION... /ISSUED 104 PM CDT FRI AUG 9 2013/
UPDATE...
18Z TAF DISCUSSION.
AVIATION...
RADAR IMAGERY SHOWS SCATTERED -SHRA/-TSRA CONTINUE TO AFFECT
CSV...WITH NEW DEVELOPMENT OF -SHRA SOUTH OF CKV/WEST OF BNA.
BASED ON RADAR TRENDS AND LATEST HRRR MODEL RUNS...WILL MENTION
VCTS/VCSH COVERAGE DUE TO SCATTERED NATURE OF CONVECTION WITH MOST
LIKELY PRECIP IMPACTS AT CSV THIS AFTERNOON/EVENING. SCALED BACK
ON PRECIP CHANCES LATE EVENING/TONIGHT BEFORE BRINGING PRECIP
BACK IN TOWARDS SUNRISE. GENERALLY VFR CIGS ANTICIPATED WITH
OCCASIONAL MVFR POSSIBLE...WITH MVFR VIS DUE TO PATCHY FOG AROUND
SUNRISE SATURDAY MORNING AT CKV/CSV. LIGHT SOUTHWEST TO SOUTH
WINDS EXPECTED THROUGH THE TAF PERIOD.
55
PREV DISCUSSION... /ISSUED 1051 AM CDT FRI AUG 9 2013/
UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
154 PM CDT FRI AUG 9 2013
.MESOSCALE UPDATE...
MESO CONVECTIVE VORTICITY CENTER APPROACHING POPLAR BLUFF AT THIS
TIME. MCV KICKED OFF WHAT APPEARS TO BE A GRAVITY WAVE THAT HAS
JUST CROSSED MISSISSIPPI RIVER. WINDS TURNED WEST AT MEMPHIS WITH
ITS PASSAGE. THIS FEATURE WILL NEED TO BE WATCHED AS IT APPROACHES THE
TENNESSEE RIVER AND MOVES EASTWARD. GRAVITY WAVES CAN IGNITE
STORMS AND INTENSIFY THEM QUICKLY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 104 PM CDT FRI AUG 9 2013/
UPDATE...
18Z TAF DISCUSSION.
AVIATION...
RADAR IMAGERY SHOWS SCATTERED -SHRA/-TSRA CONTINUE TO AFFECT
CSV...WITH NEW DEVELOPMENT OF -SHRA SOUTH OF CKV/WEST OF BNA.
BASED ON RADAR TRENDS AND LATEST HRRR MODEL RUNS...WILL MENTION
VCTS/VCSH COVERAGE DUE TO SCATTERED NATURE OF CONVECTION WITH MOST
LIKELY PRECIP IMPACTS AT CSV THIS AFTERNOON/EVENING. SCALED BACK
ON PRECIP CHANCES LATE EVENING/TONIGHT BEFORE BRINGING PRECIP
BACK IN TOWARDS SUNRISE. GENERALLY VFR CIGS ANTICIPATED WITH
OCCASIONAL MVFR POSSIBLE...WITH MVFR VIS DUE TO PATCHY FOG AROUND
SUNRISE SATURDAY MORNING AT CKV/CSV. LIGHT SOUTHWEST TO SOUTH
WINDS EXPECTED THROUGH THE TAF PERIOD.
55
PREV DISCUSSION... /ISSUED 1051 AM CDT FRI AUG 9 2013/
UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
104 PM CDT FRI AUG 9 2013
.UPDATE...
18Z TAF DISCUSSION.
&&
.AVIATION...
RADAR IMAGERY SHOWS SCATTERED -SHRA/-TSRA CONTINUE TO AFFECT
CSV...WITH NEW DEVELOPMENT OF -SHRA SOUTH OF CKV/WEST OF BNA.
BASED ON RADAR TRENDS AND LATEST HRRR MODEL RUNS...WILL MENTION
VCTS/VCSH COVERAGE DUE TO SCATTERED NATURE OF CONVECTION WITH MOST
LIKELY PRECIP IMPACTS AT CSV THIS AFTERNOON/EVENING. SCALED BACK
ON PRECIP CHANCES LATE EVENING/TONIGHT BEFORE BRINGING PRECIP
BACK IN TOWARDS SUNRISE. GENERALLY VFR CIGS ANTICIPATED WITH
OCCASIONAL MVFR POSSIBLE...WITH MVFR VIS DUE TO PATCHY FOG AROUND
SUNRISE SATURDAY MORNING AT CKV/CSV. LIGHT SOUTHWEST TO SOUTH
WINDS EXPECTED THROUGH THE TAF PERIOD.
55
&&
.PREV DISCUSSION... /ISSUED 1051 AM CDT FRI AUG 9 2013/
UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1051 AM CDT FRI AUG 9 2013
.UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
634 AM CDT FRI AUG 9 2013
.UPDATE...FOR 12Z AVIATION DISCUSSION.
&&
.AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
&&
.PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
313 AM CDT FRI AUG 9 2013
DISCUSSION...
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 88 71 88 71 / 60 60 60 40
CLARKSVILLE 88 69 87 68 / 60 60 60 40
CROSSVILLE 83 66 81 67 / 60 50 70 40
COLUMBIA 89 71 89 72 / 40 50 60 40
LAWRENCEBURG 88 71 90 71 / 40 40 60 40
WAVERLY 88 69 88 70 / 60 60 60 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1158 PM CDT THU AUG 8 2013
.UPDATE...FOR 06Z AVIATION.
&&
.AVIATION...06Z TAF DISCUSSION.
WITH THE CURRENT TRENDS AND WHAT SEEMS TO BE A STABLE YET MOIST
ATMOSPHERE...HAVE PUSHED PREVAILING RAIN AND VCTS BACK UNTIL 12Z.
THIS DOES NOT NEGATE LOWER FLIGHT CATEGORIES THOUGH. IFR TO MVFR
CONDITIONS WILL LIKELY SETTLE INTO MIDDLE TENNESSEE BY DAYBREAK.
THE ONE FACTOR THAT MAY STIFLE STRATUS/FOG DEVELOPMENT IS THE
CURRENT HIGH CLOUD SHIELD. WILL GO AHEAD AND PREVAIL THESE CLOUDS
AS SATELLITE SHOWS SOME CLEARING IS POSSIBLE WITHIN THE NEXT 3
HOURS. WINDS WILL BE LIGHT...AND VEER TO THE SOUTHWEST BY FRIDAY
AFTERNOON.
UNGER
&&
.PREV DISCUSSION... /ISSUED 1005 PM CDT THU AUG 8 2013/
UPDATE...ACTIVITY OVER WEST TENNESSEE IS DIMINISHING RAPIDLY AS
OUR QUIET WEATHER CONTINUES THIS EVENING. SURFACE FRONT WILL
INCH CLOSER TO MIDDLE TENNESSEE OVERNIGHT. HRRR SHOWS VERY LITTLE
PRECIPITATION MOVING ACROSS MIDDLE TENNESSEE OVER THE NEXT SEVERAL
HOURS, ALTHOUGH THE LATEST NAM SHOWS AN AXIS OF 850 MB MOISTURE
AND POSITIVE OMEGA PUSHING THROUGH THE MID STATE AFTER 06Z. GIVEN
THAT THE ATMOSPHERE REMAINS VERY MOIST AND MODESTLY UNSTABLE, AND
THE NOCTURNAL STORMS THAT DEVELOPED LAST NIGHT, AM LOATHE TO LOWER
POP`S THIS TIME. SO WILL LEAVE THE CURRENT FORECAST ALONE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
633 PM CDT SAT AUG 10 2013
.DISCUSSION...
See aviation discussion below.
&&
.AVIATION...
Scattered showers and thunderstorms have developed across much of
the area with MAF about the only TAF site not in danger of having TS
on station. However the storms today have been short lived with not
much lightning so even the other sites with TEMPO TS may miss out.
The convective threat will increase over the next few hours then
diminish near midnight and early tomorrow morning. Tomorrow the main
focus for thunderstorms will be in SE NM and the mountains west of
the other TAF sites. VFR conditions expected through the period
except perhaps briefly in TS.
Hennig
&&
.PREV DISCUSSION... /ISSUED 247 PM CDT SAT AUG 10 2013/
DISCUSSION...
A weak cold front that had moved into the region yesterday had a bit
of a push this morning from overnight convection and is now stalled
from the Big Bend eastward into central TX. The NAM and RUC have
convection developing along southern portions of the boundary and
rapidly developing CU marking this boundary can be seen on visible
satellite. A few showers already showing up across the southeastern
zones and went ahead and added isolated mention to this area for the
remainder of today. Otherwise, easterly upslope flow and a
persistent theta e ridge may result in showers and thunderstorms
across the higher terrain and SE New Mexico this evening and could
linger overnight with upper level weaknesses moving through New
Mexico on the western periphery of the upper ridge. Will keep
chance POPs going across these areas during this time.
The NAM has convection developing once again Sunday across much of
the region. It is the most aggressive with QPF output and will only
include slight chance across most of the area. Think highest chances
will remain across SE NM as another disturbance moves east through
the TX Panhandle Sunday afternoon. Rain chances will continue into
the overnight hours mainly across the Permian Basin. PWATs will
remain higher through the weekend so will keep mention of potential
heavy rainfall. Monday, the upper ridge begins to move back west and
rain chances decrease for our area for at least a few days. In
general, temperatures will remain cooler than what we experienced
last week.
By mid week, the upper ridge will be centered over the Desert
Southwest leaving west TX and SE NM under weak NW flow aloft. Hard
to tell if any disturbances moving SE in the flow aloft will affect
us just yet but will keep an eye on it. Models are hanging onto a
weak cold front sagging into the region Wednesday afternoon/evening,
increasing rain chances across the northern PB through Thursday
morning. For now, will hold off on increasing POPs in the grids.
Expect temperatures to cool toward normals for the end of the work
week.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 71 94 73 95 / 30 10 20 10
BIG SPRING TX 73 96 74 96 / 20 10 20 10
CARLSBAD NM 69 91 72 95 / 30 20 10 10
DRYDEN TX 77 99 76 98 / 20 20 10 10
FORT STOCKTON TX 72 95 72 96 / 20 20 10 10
GUADALUPE PASS TX 65 87 67 89 / 30 20 10 10
HOBBS NM 67 89 71 92 / 30 20 20 10
MARFA TX 62 86 63 86 / 30 20 10 10
MIDLAND INTL AIRPORT TX 72 95 73 96 / 20 10 20 10
ODESSA TX 73 95 74 95 / 20 10 20 10
WINK TX 74 96 75 98 / 30 20 20 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
44/27
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
307 PM CDT FRI AUG 9 2013
.SHORT TERM...
.Tonight and Saturday...
Isolated severe thunderstorms with damaging winds possible again
this afternoon and evening. The best potential will be in the Big
Country, along a weak cold front along the I-20 corridor.
Discussion:
Conditions are similar to yesterday with an inverted V sounding.
Instability was fairly high. RAP ML CAPES ranged from 2000-3000 J/KG
in the Big Country and Concho Valley, with the highest values near
Sweetwater. Focus for initial storm development will be a weak front
along the I-20 corridor...although a few storms will likely develop
farther south along thunderstorm outflow boundaries. Main
thunderstorm threat will be damaging winds. With weak steering
currents, storm movement will be slow. This may also bring
localized flooding in urban areas.
The front is expected to move south Saturday afternoon...becoming
stationary somewhere along the I-10 corridor...although placement is
uncertain. The main threat will be strong gusty winds and dangerous
lightning.
.LONG TERM...
.Saturday Night...
Slight chance of storms will linger into the evening hours.
Whatever is left of the weak cold front will remain somewhere across
West Central Texas, along with whatever outflow boundaries may still
be in the area. Any storms that develop during the heat of the day
will keep going until shortly after sunset before dissipating.
.Sunday into Wednesday...
A dry pattern will prevail, with temperatures not quite as hot.
Upper level ridge of high pressure takes a bigger role for early
next week, slowly shifting back to the west. Low level temperatures
and 850 mb readings are forecasted to be cooler by a few degrees, so
forecast highs at or hopefully just below the 100 degree mark. With
the ridge in place overhead and without a boundary to aid, getting
any thunderstorms to develop will be extremely tough. Will opt to
keep the forecast dry.
.Wednesday Night into Friday...
Storms will be possible again across the Big Country.
By late Wednesday, the upper level ridge will have shifted far
enough to the west to put West Central Texas into northwest flow.
This is typically a wetter pattern, as storms develop across the
Panhandle during the afternoon and move southeast into the area
during the overnight hours. Best chances look to be across the Big
Country and Heartland with the chances decreasing to the southwest.
Have inserted pops for the northeast portions of the area for now,
and leave the remainder of the area dry. But if the northwest flow
sets up as the models suggest, may have to expand the rainfall
coverage as we get into next week.
Otherwise, northwest flow is usually a little cooler as well. This
is shown in the model guidance, showing highs near climatology
normals in the mid to upper 90s.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 100 71 96 76 96 / 20 30 20 20 10
SAN ANGELO 103 71 99 74 97 / 20 30 20 20 10
JUNCTION 103 72 100 75 97 / 10 5 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/07
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1035 AM CDT FRI AUG 9 2013
.UPDATE...
NE-SW BAND OF MORNING CONVECTION HAS BUT ABOUT ALL DIED AWAY
OUTSIDE OF A FEW SPRINKLES FROM COMANCHE TO STEPHENVILLE. VISIBLE
SATELLITE INDICATES A SHARP CONTRAST FROM CLOUDY SKIES UNDERNEATH
THIS ONE-TWO COUNTYWIDE BAND...TO MOSTLY SUNNY SKIES. MEANWHILE A
WEAK SURFACE LOW/BOUNDARY WAS ORIENTED FROM NEAR GRAHAM TO BETWEEN
BOWIE AND WICHITA FALLS.
THE WEAK SURFACE BOUNDARY IS EXPECTED TO SLOWLY MOVE SOUTHEAST
ACROSS THE NORTHWEST COUNTIES PER THE RUC/SREF FORECASTS. BEST
PWATS BETWEEN 1.75-2.00 INCHES WILL ALSO BE IN THE VICINITY ON THE
NORTHWEST EDGE OF THE UPPER RIDGE ANCHORED OVER THE WESTERN GULF
COAST. AS A SHORTWAVE DISTURBANCE OVER SE COLORADO DROPS SE OVER
CENTRAL/WESTERN OKLAHOMA...ENOUGH DIFFERRENTIAL HEATING/LIFT OFF THE
NORTHWEST EDGE OF MORNING CLOUDS WILL COINCIDE WITH RICH MOISTURE
AND INSTABILITY FOR ISOLATED TO SCATTERED STORMS MAINLY NORTH OF
I-20 AND WEST OF I-35W LATER THIS AFTERNOON AND EVENING.
FREQUENT LIGHTNING AND GUSTY DOWNBURST WINDS WOULD BE THE MAIN
THREATS WITH ANY STRONG TO BRIEF SEVERE STORMS THROUGH SUNSET.
ISOLATED ACTIVITY MAY MAINTAIN AFTER DARK IN THIS AREA WITH THE
SHORTWAVE NEARBY...BUT OVERALL CONVECTIVE COVERAGE SHOULD GRADUALLY
DIMINISH WITH LOSS OF STRONG DAYTIME HEATING.
WHERE THE WEAK SURFACE BOUNDARY ENDS UP SATURDAY IS ANYONE/S GUESS
AND HAVE LEFT CURRENT POPS INTACT.
05/
&&
.AVIATION...
FOR THE 12Z TAFS...EARLY MORNING SHOWERS AND THUNDERSTORMS AROUND
THE DFW AREA IS THE PRIMARY AVIATION WEATHER CONCERN TODAY.
ALTHOUGH RAIN SHOWERS AND THUNDERSTORMS TO THE WEST AND SOUTHWEST
OF THE DFW AREA HAVE BEEN SLOW TO BUILD OVER THE METROPLEX...THIS
ACTIVITY IS STILL EXPECTED TO MOVE/DEVELOP NORTHEAST THIS MORNING.
THE HRRR REMAINS PERSISTENT IN INDICATING SCATTERED SHOWERS OVER
THE DFW METROPLEX THIS MORNING AND IR SATELLITE INDICATES COOLING
CLOUD TOPS SPREADING OVER TARRANT AND DALLAS COUNTIES. COOLING
CLOUD TOPS ARE EVIDENCE OF SOME MID-LEVEL ASCENT ORIENTED
SOUTHEAST OF A QUASI-STATIONARY FRONT LOCATED NORTHWEST OF THE DFW
METROPLEX.
WITH FORCING FOR ASCENT INDICATED BY SATELLITE IMAGERY...CONFIDENCE
IN THE HRRR FORECAST IS SUFFICIENTLY HIGH TO INCLUDE A MENTION OF
VCTS IN METROPLEX AREA TAFS THIS MORNING THROUGH 16Z. EXPECT RAIN
SHOWERS WITH ISOLATED STORMS TO DEVELOP OVER TARRANT COUNTY AFTER
12Z...SPREADING EAST INTO DALLAS COUNTY THROUGH 14Z.
AFTERNOON AND SURFACE BASED THUNDERSTORM ACTIVITY IS EXPECTED TO
REMAIN CLOSELY TIED TO THE STATIONARY FRONT...AND THEREFORE SHOULD
REMAIN NORTHWEST OF THE DFW METROPLEX. OTHERWISE...VFR CONDITIONS
ARE EXPECTED THROUGH THE FORECAST PERIOD.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 346 AM CDT FRI AUG 9 2013/
ISOLATED SHOWERS EXPECTED THIS MORNING IN A BAND OF ENHANCED
MOISTURE EXTENDING FROM EASTLAND TO GAINESVILLE. THIS ACTIVITY
WILL DISSIPATE BY MID TO LATE MORNING...WITH DIMINISHING CLOUD
COVER LEADING TO HIGH TEMPERATURES ONCE AGAIN AT OR ABOVE 100 IN
MOST AREAS. LIKE YESTERDAY...A FEW AREAS THAT EXPERIENCE SHOWERS
AND MORE PERSISTENT MORNING CLOUD COVER MAY REMAIN IN THE UPPER
90S FOR HIGHS. SURFACE DEWPOINTS ARE EXPECTED TO MIX OUT INTO THE
50S AND LOWER 60S IN MOST AREAS AGAIN THIS AFTERNOON...WHICH
SHOULD HELP KEEP HEAT INDEX VALUES BELOW 105. HOWEVER...A FEW
VALUES NEAR OR JUST ABOVE 105 CAN BE EXPECTED THIS AFTERNOON...AND
AGAIN SATURDAY AFTERNOON...BEFORE THE DRIER AIR MIXES DOWN TO THE
NEAR SURFACE LAYER.
FOR THIS AFTERNOON...EXPECT WIDELY SCATTERED THUNDERSTORM
DEVELOPMENT TO FOCUS ALONG A WEAK SURFACE TROUGH/STATIONARY FRONT
THAT CURRENTLY EXTENDS JUST SOUTH OF THE RED RIVER. ADDITIONAL
OUTFLOW BOUNDARIES EXIST ACROSS NORTH TEXAS...BUT SUBSIDENCE FROM
UPPER HIGH IS STRONGER FURTHER SOUTH. WILL FORECAST 20 POPS IN AN
AREA NORTHWEST OF DFW NEAR THE EXPECTED LOCATION OF THE FRONTAL
BOUNDARY NEAR MAX HEATING TIME. IF SURFACE DEWPOINTS CAN REMAIN IN
THE MID 60S NEAR THE BOUNDARY...LOCAL SURFACE BASED CAPE VALUES
AROUND 2000 J/KG CAN BE EXPECTED. ANY STORM THAT DOES DEVELOP OR
SPREAD INTO NORTH TEXAS NEAR OR JUST AFTER MAX HEATING WILL BE
CAPABLE OF DAMAGING DOWNBURST WINDS.
EXPECT ANY REMAINING CONVECTION TO DISSIPATE BY MIDNIGHT
TONIGHT...WITH PARTLY CLOUDY SKIES EXPECTED. FOR SATURDAY AND
SUNDAY AFTERNOON AND EVENING...EXPECT THE BEST CHANCES FOR
CONVECTION TO BE NEAR THE SURFACE BOUNDARY WHICH IS FORECAST TO
EXTEND ACROSS THE EASTERN AND SOUTHERN PARTS OF THE CWA. THE
OPERATIONAL NAM SUGGESTS THE POTENTIAL FOR A GREATER COVERAGE OF
CONVECTION JUST SOUTH AND SOUTHEAST OF THE METROPLEX SATURDAY
AFTERNOON AND EVENING. HOWEVER...THAT SOLUTION IS NOT SUPPORTED BY
THE OTHER AVAILABLE GUIDANCE AND WILL THEREFORE KEEP POPS NO
HIGHER THAN 20 PERCENT. PROXIMITY OF UPPER RIDGE AND OVERALL
SHALLOW ASCENT NEAR THE BOUNDARY SUGGEST THAT THE NAM IS LIKELY
TOO WET FOR THE SATURDAY AFTN/EVE PERIOD.
DRY WEATHER EXPECTED ON MONDAY AND TUESDAY AS THE RIDGE THAT WILL
BE ALIGNED WEST-EAST ACROSS THE SOUTHERN U.S. OVER THE WEEKEND
REDEVELOPS IN A NORTH-SOUTH FASHION ALONG THE ROCKY MOUNTAINS.
WITH TROUGHING FORECAST IN THE NORTHEAST U.S...THE RESULTING
NORTHWEST FLOW PATTERN WILL BE FAVORABLE FOR A MORE SUBSTANTIAL...
ALBEIT STILL RELATIVELY WEAK...COLD FRONT TO MOVE INTO NORTH
TEXAS. WITH MOISTURE STILL IN PLACE AND UPPER RIDGE WELL OFF TO THE
WEST...EXPECT ONE OR MORE ROUNDS OF SCATTERED CONVECTION TO AFFECT
PARTS OF NORTH AND CENTRAL TEXAS. WILL SPREAD POPS FROM NORTH TO
SOUTH ACROSS THE AREA STARTING TUESDAY NIGHT AND CONTINUING
THROUGH DAY 7 /THURSDAY AUG 15/. ITS TOO EARLY TO GO HIGHER THAN
ABOUT 30 POPS...BUT LATER FORECASTS MAY RAISE THE WEDS-THURS POPS
IF PATTERN CHANGE CONTINUES TO EVOLVE AS EXPECTED. ADDITIONAL
CLOUD COVER AND AREAS OF RAIN WILL HOLD TEMPERATURES DOWN INTO THE
LOWER AND MID 90S ON THURSDAY.
09/PATRICK
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 102 78 101 80 98 / 20 10 10 10 10
WACO, TX 100 77 100 77 98 / 5 5 20 20 10
PARIS, TX 100 75 97 74 96 / 20 20 10 10 20
DENTON, TX 102 75 99 78 98 / 20 20 10 10 10
MCKINNEY, TX 102 76 101 78 98 / 20 10 10 10 20
DALLAS, TX 103 81 103 81 99 / 20 10 10 10 10
TERRELL, TX 103 77 102 78 98 / 10 10 20 20 20
CORSICANA, TX 103 77 101 79 98 / 5 5 20 20 20
TEMPLE, TX 100 74 99 75 97 / 5 5 20 20 20
MINERAL WELLS, TX 101 74 100 76 98 / 20 10 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/05
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
653 AM CDT FRI AUG 9 2013
.AVIATION...
FOR THE 12Z TAFS...EARLY MORNING SHOWERS AND THUNDERSTORMS AROUND
THE DFW AREA IS THE PRIMARY AVIATION WEATHER CONCERN TODAY.
ALTHOUGH RAIN SHOWERS AND THUNDERSTORMS TO THE WEST AND SOUTHWEST
OF THE DFW AREA HAVE BEEN SLOW TO BUILD OVER THE METROPLEX...THIS
ACTIVITY IS STILL EXPECTED TO MOVE/DEVELOP NORTHEAST THIS MORNING.
THE HRRR REMAINS PERSISTENT IN INDICATING SCATTERED SHOWERS OVER
THE DFW METROPLEX THIS MORNING AND IR SATELLITE INDICATES COOLING
CLOUD TOPS SPREADING OVER TARRANT AND DALLAS COUNTIES. COOLING
CLOUD TOPS ARE EVIDENCE OF SOME MID-LEVEL ASCENT ORIENTED
SOUTHEAST OF A QUASI-STATIONARY FRONT LOCATED NORTHWEST OF THE DFW
METROPLEX.
WITH FORCING FOR ASCENT INDICATED BY SATELLITE IMAGERY...CONFIDENCE
IN THE HRRR FORECAST IS SUFFICIENTLY HIGH TO INCLUDE A MENTION OF
VCTS IN METROPLEX AREA TAFS THIS MORNING THROUGH 16Z. EXPECT RAIN
SHOWERS WITH ISOLATED STORMS TO DEVELOP OVER TARRANT COUNTY AFTER
12Z...SPREADING EAST INTO DALLAS COUNTY THROUGH 14Z.
AFTERNOON AND SURFACE BASED THUNDERSTORM ACTIVITY IS EXPECTED TO
REMAIN CLOSELY TIED TO THE STATIONARY FRONT...AND THEREFORE SHOULD
REMAIN NORTHWEST OF THE DFW METROPLEX. OTHERWISE...VFR CONDITIONS
ARE EXPECTED THROUGH THE FORECAST PERIOD.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 346 AM CDT FRI AUG 9 2013/
ISOLATED SHOWERS EXPECTED THIS MORNING IN A BAND OF ENHANCED
MOISTURE EXTENDING FROM EASTLAND TO GAINESVILLE. THIS ACTIVITY
WILL DISSIPATE BY MID TO LATE MORNING...WITH DIMINISHING CLOUD
COVER LEADING TO HIGH TEMPERATURES ONCE AGAIN AT OR ABOVE 100 IN
MOST AREAS. LIKE YESTERDAY...A FEW AREAS THAT EXPERIENCE SHOWERS
AND MORE PERSISTENT MORNING CLOUD COVER MAY REMAIN IN THE UPPER
90S FOR HIGHS. SURFACE DEWPOINTS ARE EXPECTED TO MIX OUT INTO THE
50S AND LOWER 60S IN MOST AREAS AGAIN THIS AFTERNOON...WHICH
SHOULD HELP KEEP HEAT INDEX VALUES BELOW 105. HOWEVER...A FEW
VALUES NEAR OR JUST ABOVE 105 CAN BE EXPECTED THIS AFTERNOON...AND
AGAIN SATURDAY AFTERNOON...BEFORE THE DRIER AIR MIXES DOWN TO THE
NEAR SURFACE LAYER.
FOR THIS AFTERNOON...EXPECT WIDELY SCATTERED THUNDERSTORM
DEVELOPMENT TO FOCUS ALONG A WEAK SURFACE TROUGH/STATIONARY FRONT
THAT CURRENTLY EXTENDS JUST SOUTH OF THE RED RIVER. ADDITIONAL
OUTFLOW BOUNDARIES EXIST ACROSS NORTH TEXAS...BUT SUBSIDENCE FROM
UPPER HIGH IS STRONGER FURTHER SOUTH. WILL FORECAST 20 POPS IN AN
AREA NORTHWEST OF DFW NEAR THE EXPECTED LOCATION OF THE FRONTAL
BOUNDARY NEAR MAX HEATING TIME. IF SURFACE DEWPOINTS CAN REMAIN IN
THE MID 60S NEAR THE BOUNDARY...LOCAL SURFACE BASED CAPE VALUES
AROUND 2000 J/KG CAN BE EXPECTED. ANY STORM THAT DOES DEVELOP OR
SPREAD INTO NORTH TEXAS NEAR OR JUST AFTER MAX HEATING WILL BE
CAPABLE OF DAMAGING DOWNBURST WINDS.
EXPECT ANY REMAINING CONVECTION TO DISSIPATE BY MIDNIGHT
TONIGHT...WITH PARTLY CLOUDY SKIES EXPECTED. FOR SATURDAY AND
SUNDAY AFTERNOON AND EVENING...EXPECT THE BEST CHANCES FOR
CONVECTION TO BE NEAR THE SURFACE BOUNDARY WHICH IS FORECAST TO
EXTEND ACROSS THE EASTERN AND SOUTHERN PARTS OF THE CWA. THE
OPERATIONAL NAM SUGGESTS THE POTENTIAL FOR A GREATER COVERAGE OF
CONVECTION JUST SOUTH AND SOUTHEAST OF THE METROPLEX SATURDAY
AFTERNOON AND EVENING. HOWEVER...THAT SOLUTION IS NOT SUPPORTED BY
THE OTHER AVAILABLE GUIDANCE AND WILL THEREFORE KEEP POPS NO
HIGHER THAN 20 PERCENT. PROXIMITY OF UPPER RIDGE AND OVERALL
SHALLOW ASCENT NEAR THE BOUNDARY SUGGEST THAT THE NAM IS LIKELY
TOO WET FOR THE SATURDAY AFTN/EVE PERIOD.
DRY WEATHER EXPECTED ON MONDAY AND TUESDAY AS THE RIDGE THAT WILL
BE ALIGNED WEST-EAST ACROSS THE SOUTHERN U.S. OVER THE WEEKEND
REDEVELOPS IN A NORTH-SOUTH FASHION ALONG THE ROCKY MOUNTAINS.
WITH TROUGHING FORECAST IN THE NORTHEAST U.S...THE RESULTING
NORTHWEST FLOW PATTERN WILL BE FAVORABLE FOR A MORE SUBSTANTIAL...
ALBEIT STILL RELATIVELY WEAK...COLD FRONT TO MOVE INTO NORTH
TEXAS. WITH MOISTURE STILL IN PLACE AND UPPER RIDGE WELL OFF TO THE
WEST...EXPECT ONE OR MORE ROUNDS OF SCATTERED CONVECTION TO AFFECT
PARTS OF NORTH AND CENTRAL TEXAS. WILL SPREAD POPS FROM NORTH TO
SOUTH ACROSS THE AREA STARTING TUESDAY NIGHT AND CONTINUING
THROUGH DAY 7 /THURSDAY AUG 15/. ITS TOO EARLY TO GO HIGHER THAN
ABOUT 30 POPS...BUT LATER FORECASTS MAY RAISE THE WEDS-THURS POPS
IF PATTERN CHANGE CONTINUES TO EVOLVE AS EXPECTED. ADDITIONAL
CLOUD COVER AND AREAS OF RAIN WILL HOLD TEMPERATURES DOWN INTO THE
LOWER AND MID 90S ON THURSDAY.
09/PATRICK
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 102 78 101 80 98 / 20 10 10 10 10
WACO, TX 100 77 100 77 98 / 5 5 20 20 10
PARIS, TX 100 75 97 74 96 / 10 10 10 10 20
DENTON, TX 102 75 99 78 98 / 20 20 10 10 10
MCKINNEY, TX 102 76 101 78 98 / 20 10 10 10 20
DALLAS, TX 103 81 103 81 99 / 10 10 10 10 10
TERRELL, TX 103 77 102 78 98 / 5 10 20 20 20
CORSICANA, TX 103 77 101 79 98 / 5 5 20 20 20
TEMPLE, TX 100 74 99 75 97 / 5 5 20 20 20
MINERAL WELLS, TX 101 74 100 76 98 / 30 20 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
115 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT IS EXPECTED TO APPROACH THE REGION FROM
THE NORTHWEST THIS EVENING BEFORE PASSING SOUTHEAST THROUGH OUR
AREA THIS WEEKEND. HIGH PRESSURE OVER THE UPPER MIDWEST SHIFTS
SOUTHEAST THROUGH THE MID ATLANTIC BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT FRIDAY...
FOG/STRATUS FADING WITH BETTER HEATING UNDER LESS CLOUD COVER
THIS MORNING AND EXPECT MOST TO CLEAR IN THE NEXT HOUR OR SO. OTRW
FRONT REMAINS STALLED OUT ACROSS THE SRN OHIO VALLEY THIS MORNING
PRECEDED BY A BAND OF SHRA/TSRA ASSOCIATED WITH WEAK S/W ENERGY
ALONG THE RESIDUAL PRE-FRONTAL ZONE. MORNING SOUNDINGS SHOW BETTER
FLOW ALOFT AHEAD OF THE FRONT/WAVE THIS MORNING WITH DECENT
WESTERLY FLOW WHICH SHOULD HELP SHRA/TSRA MOVE A BIT FASTER THIS
AFTERNOON. HOWEVER UNIDIRECTIONAL TRAJECTORY MAY OFFSET THIS BY
ALLOWING STORMS TO ALIGN IN BANDS ESPCLY AS THE SFC-85H STEERING
BRIEFLY TURNS MORE SW WITH THE PASSING VORT NOW OVER KY AROUND MID
AFTERNOON. THIS SHOULD HELP PROMPT DEVELOPMENT ALONG THE SRN BLUE
RIDGE AS SEEN VIA SEVERAL SOLNS WITH ANOTHER AREA ACROSS THE FAR
NW WITH THE SAGGING CONVECTION TO THE NW. LATEST MODIFIED RAOBS
ALSO SHOW MUCH MORE CAPE/INSTABILITY PER MORE INSOLATION THIS
AFTERNOON ESPCLY BLUE RIDGE EAST WHERE STRONGER STORMS APPEAR
LIKELY PER BETTER JET ALOFT. STILL APPEARS THREAT FOR FLOODING
RAINFALL WILL BE MORE LOCALIZED UNLESS BLUE RIDGE CONVECTION AND
COVERAGE TO THE NW COMES TOGETHER SO STILL HOLDING OFF ON ANY
WATCHES FOR NOW.
OTRW HAVE ADJUSTED POPS FOR SLOWER ARRIVAL NW GIVEN CURRENT RADAR
TRENDS AND INCREASED TO LIKELYS IN A BAND BLUE RIDGE VICINITY
WHERE 2-3K J/KG CAPES POSSIBLE. WEST WIND ALONG WITH COMPRESSION
AHEAD OF THE FRONT SHOULD COMBO WITH HEATING AND +19-20C AT 85H TO
PUSH HIGHS TO ARND 90 SE AND MAINLY 80S ELSW PER OBSERVED
THICKNESS.
PREVIOUS DISCUSSION AS OF 330 AM EDT FRIDAY...
RADARS QUIET THIS MORNING WITH ONLY ONE LONE SHOWER EXITING NRN
GREENBRIER COUNTY WITH MOST CONVECTION CENTERED WITH AND AHEAD OF A
SHORTWAVE AROUND CINCINNATI. THE 12Z ECMWF/00Z GFS ZERO IN ON THIS
SHORTWAVE AND PRECIP AND MAINLY SEE IT SHIFTING ENE INTO NRN WV
LATER THIS MORNING WITH A FEW SHOWERS MAKING ITS WAY INTO SE WV. FOR
EARLY TODAY WILL BE DEALING WITH AREAS OF FOG...LOCALLY DENSE AS IT
HAS CLEARED OUT SOME ASIDE FROM SOME HIGH CLOUDS. THIS FOG WILL BE
GOING AWAY AROUND 900 AM.
LOOKING AT WSW FLOW BACKING DURING THE DAY AND AFTER MIDDAY MODELS
SHOWING SOME LOW LVL CONVERGENCE ALONG THE BLUE RIDGE WITH A
PREFRONTAL TROUGH...WITH UPPER SUPPORT AND MAIN FRONT STAYING ACROSS
THE OHIO VALLEY INTO THE MID ATLANTIC. THINK COVERAGE WILL AGAIN
BECOME SCATTERED TO NUMEROUS OVER THE MOUNTAINS THEN SHIFT TO THE
PIEDMONT AS FLOW BACKS. WITH BETTER MIXING AND MORE SUNSHINE...THE
INSTABILITY AND CONVECTIVE TEMPS SUPPORT MORE THUNDER. STORMS WILL
BE HEAVY RAIN PRODUCERS AND MEAN FLOW SHOWING STORM MOVEMENT OF 10
TO 20 MPH. OVERALL THREAT FOR SVR THUNDERSTORMS AND FLASH FLOODING
REMAINS ISOLATED...SO NO WATCHES FOR FLASH FLOODING EXPECTED AND
WILL CONTINUE TO MENTION HEAVY RAIN...ISOLATED SVR IN THE HWO.
AS WE HEAD INTO LATE AFTERNOON AND EARLY EVENING THE LOW LVL FLOW
VEERS TO THE WEST AND THE GFS ESPECIALLY DRIES THE LEE SIDE OF THE
MOUNTAINS OUT WHILE HOLDING ONTO CONVECTION IN THE PIEDMONT...SO
WILL BE LEANING TOWARD LOWER POPS IN THE NEW RIVER VALLEY/FOOTHILLS
BY DUSK WHILE KEEPING THE WRN SLOPES AND PIEDMONT WITH HIGHER POPS.
OUR LOCAL WRF AND HRRR SHOWING THIS TO BE THE CASE AS WELL.
THINK WILL SEE SHOWERS AND STORMS SUBSIDE AGAIN BY LATE
EVENING/MIDNIGHT ESPECIALLY IN THE EAST WITH LOSS OF HEATING BUT
EXPECT THE THREAT OF SHOWERS TO REMAIN OVER THE WV/FAR SW VA MTNS
AHEAD OF THE FRONT AND CLOSER TO THE UPPER LEVEL SUPPORT.
FOR HIGHS TODAY WENT CLOSE TO THE ECMWF MOS AS THE GFS SEEMS TO WARM
AND NAM TOO COOL. LOOKING AT WARMER TEMPS WITH MORE SUN AND MIXING
BEFORE STORMS SET IN...WITH LOWER 80S WEST TO MID 80S TO NEAR 90
EAST.
TONIGHT REMAINS MUGGY WITH LOWS GENERALLY IN THE MID TO UPPER 60S
MOUNTAINS INTO THE LOWER 70S EAST.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EDT FRIDAY...
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THIS WEEKEND
INTO THE NEXT WORKWEEK AS A COLD FRONT MAKES ITS WAY ACROSS OUR
REGION. IN STICKING CLOSE WITH THE ECMWF MODEL SOLUTION...EXPECT TO
START SATURDAY OFF WITH THE COLD FRONT SITUATED NEAR THE INTERSTATE
81 CORRIDOR...WITH THE FRONT DRIFTING SLOWLY SOUTHWARD THROUGH THE
DAY...PERHAPS AIDED IN ITS PUSH BY OUTFLOW FROM AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS. BY SUNDAY MORNING...THE FRONT IS EXPECTED
TO ADVANCE INTO NORTH CAROLINA...WHERE IT WILL STALL AND BEGIN TO
WASH OUT ON MONDAY AS ANOTHER COLD FRONT APPROACHES FROM THE UPPER
MIDWEST.
DESPITE THE PASSAGE OF THE FRONT...WILL STILL SEE ABUNDANT LOW LEVEL
MOISTURE ACROSS OUR AREA AS DRIER AIR LINGERS TO OUR NORTH. MINOR
DISTURBANCES ALOFT WILL CONTINUALLY PASS ALONG THE FRONT FROM THE
WEST DURING THE WEEKEND...AND WILL TRIGGER ROUNDS OF SHOWERS AND
THUNDERSTORMS...MAINLY EACH AFTERNOON AND EVENING WHEN ENHANCED BY
DAYTIME HEATING. AS IN PREVIOUS NIGHTS...BELIEVE WE WILL SEE A
DRASTIC REDUCTION IN THE AMOUNT OF SHOWER ACTIVITY AFTER
SUNSET...ALTHOUGH CANNOT RULE A FEW SHOWERS DURING THE OVERNIGHTS.
WILL ALSO POINT OUT THE POSSIBILITY OF A FEW STRONG STORMS ON
SATURDAY AND SUNDAY...MORE SO SOUTH OF INTERSTATE 81. WHILE STRONG
THUNDERSTORM WINDS AND FREQUENT LIGHTNING WILL BE CONCERNS...THE
GREATEST CONCERN WILL BE FROM LOCALLY HEAVY RAIN AND THE POSSIBILITY
OF FLASH FLOODING. ANY FLOODING SHOULD REMAIN LOCAL IN SCALE...BUT
MAY DEVELOP QUICKLY IN STORMS WITH HIGH RAINFALL RATES...AND
ESPECIALLY IN LOCATIONS WITH SATURATED SOILS FROM RECENT HEAVY RAIN.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
AS OF 100 PM EDT FRIDAY...
OVERALL FLAVOR OF THE FORECAST WILL BE CONVECTION ALONG AND WEST
OF THE BLUE RIDGE THROUGH EARLY AFTERNOON...WITH THE FOCUS
SHIFTING TO THE PIEDMONT LATER THIS AFTERNOON...THEN FOG/STRATUS
FOR BLUE RIDGE WESTWARD OVERNIGHT. HAVE LOW CONFIDENCE IN VFR
CIGS/VSBYS OVERNIGHT...ESPECIALLY IF THESE AIRPORTS SEE ANY
SIGNIFICANT DIRECT PRECIPITATION TODAY. HOWEVER...FEEL THE
GENERAL WIND DIRECTION GOING TO WLY WILL LEAD TO SOME DOWNSLOPE
AND HELP MITIGATE NOCTURNAL FOG AND LOW CIGS. WILL GO AGAINST MOS
GUIDANCE HERE AND RATHER THAN HEDGE...WILL GO WITH AN OPTIMISTIC
FORECAST FOR KDAN AND KLYH.
MODELS SEEM TO HAVE A DECENT HANDLE ON PCPN TRENDS AND CONTINUE
TO SQUEEZE OUT SOME LIGHT SHOWERS FOR THE OVERNIGHT ALONG AND WEST
OF THE BLUE RIDGE IN LIGHT W/NWLY FLOW. WILL BRING IN THE LOW
CLOUDS AND FOG AT KBLF/KLWB/KBCB AND USE VCSH TO HANDLE THE PCPN
AT KBLF/KLWB. KROA WILL BE IN THE TRANSITION ZONE BUT WILL SHADE
THINGS TO THE OPTIMISTIC SIDE AND USE A TEMPO FOR SOME MVFR
CIGS/VSBY.
...AVIATION EXTENDED...
THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE WEEKEND AND KEEPS THE
THREAT OF SHOWERS/STORMS AROUND. THE FRONT MAY SLIP SOUTH OF THE
AREA BY MONDAY INTO TUESDAY WITH STILL SOME THREAT OF SHOWERS OVER
THE SRN CWA FROM DAN-BCB-BLF.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...MBS/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1017 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT IS EXPECTED TO APPROACH THE REGION FROM
THE NORTHWEST THIS AFTERNOON BEFORE PASSING SOUTHEAST THROUGH OUR
AREA THIS WEEKEND. HIGH PRESSURE OVER THE UPPER MIDWEST SHIFTS
SOUTHEAST THROUGH THE MID ATLANTIC BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT FRIDAY...
FOG/STRATUS FADING WITH BETTER HEATING UNDER LESS CLOUD COVER
THIS MORNING AND EXPECT MOST TO CLEAR IN THE NEXT HOUR OR SO. OTRW
FRONT REMAINS STALLED OUT ACROSS THE SRN OHIO VALLEY THIS MORNING
PRECEDED BY A BAND OF SHRA/TSRA ASSOCIATED WITH WEAK S/W ENERGY
ALONG THE RESIDUAL PRE-FRONTAL ZONE. MORNING SOUNDINGS SHOW BETTER
FLOW ALOFT AHEAD OF THE FRONT/WAVE THIS MORNING WITH DECENT
WESTERLY FLOW WHICH SHOULD HELP SHRA/TSRA MOVE A BIT FASTER THIS
AFTERNOON. HOWEVER UNIDIRECTIONAL TRAJECTORY MAY OFFSET THIS BY
ALLOWING STORMS TO ALIGN IN BANDS ESPCLY AS THE SFC-85H STEERING
BRIEFLY TURNS MORE SW WITH THE PASSING VORT NOW OVER KY AROUND MID
AFTERNOON. THIS SHOULD HELP PROMPT DEVELOPMENT ALONG THE SRN BLUE
RIDGE AS SEEN VIA SEVERAL SOLNS WITH ANOTHER AREA ACROSS THE FAR
NW WITH THE SAGGING CONVECTION TO THE NW. LATEST MODIFIED RAOBS
ALSO SHOW MUCH MORE CAPE/INSTABILITY PER MORE INSOLATION THIS
AFTERNOON ESPCLY BLUE RIDGE EAST WHERE STRONGER STORMS APPEAR
LIKELY PER BETTER JET ALOFT. STILL APPEARS THREAT FOR FLOODING
RAINFALL WILL BE MORE LOCALIZED UNLESS BLUE RIDGE CONVECTION AND
COVERAGE TO THE NW COMES TOGETHER SO STILL HOLDING OFF ON ANY
WATCHES FOR NOW.
OTRW HAVE ADJUSTED POPS FOR SLOWER ARRIVAL NW GIVEN CURRENT RADAR
TRENDS AND INCREASED TO LIKELYS IN A BAND BLUE RIDGE VICINITY
WHERE 2-3K J/KG CAPES POSSIBLE. WEST WIND ALONG WITH COMPRESSION
AHEAD OF THE FRONT SHOULD COMBO WITH HEATING AND +19-20C AT 85H TO
PUSH HIGHS TO ARND 90 SE AND MAINLY 80S ELSW PER OBSERVED
THICKNESS.
PREVIOUS DISCUSSION AS OF 330 AM EDT FRIDAY...
RADARS QUIET THIS MORNING WITH ONLY ONE LONE SHOWER EXITING NRN
GREENBRIER COUNTY WITH MOST CONVECTION CENTERED WITH AND AHEAD OF A
SHORTWAVE AROUND CINCINNATI. THE 12Z ECMWF/00Z GFS ZERO IN ON THIS
SHORTWAVE AND PRECIP AND MAINLY SEE IT SHIFTING ENE INTO NRN WV
LATER THIS MORNING WITH A FEW SHOWERS MAKING ITS WAY INTO SE WV. FOR
EARLY TODAY WILL BE DEALING WITH AREAS OF FOG...LOCALLY DENSE AS IT
HAS CLEARED OUT SOME ASIDE FROM SOME HIGH CLOUDS. THIS FOG WILL BE
GOING AWAY AROUND 900 AM.
LOOKING AT WSW FLOW BACKING DURING THE DAY AND AFTER MIDDAY MODELS
SHOWING SOME LOW LVL CONVERGENCE ALONG THE BLUE RIDGE WITH A
PREFRONTAL TROUGH...WITH UPPER SUPPORT AND MAIN FRONT STAYING ACROSS
THE OHIO VALLEY INTO THE MID ATLANTIC. THINK COVERAGE WILL AGAIN
BECOME SCATTERED TO NUMEROUS OVER THE MOUNTAINS THEN SHIFT TO THE
PIEDMONT AS FLOW BACKS. WITH BETTER MIXING AND MORE SUNSHINE...THE
INSTABILITY AND CONVECTIVE TEMPS SUPPORT MORE THUNDER. STORMS WILL
BE HEAVY RAIN PRODUCERS AND MEAN FLOW SHOWING STORM MOVEMENT OF 10
TO 20 MPH. OVERALL THREAT FOR SVR THUNDERSTORMS AND FLASH FLOODING
REMAINS ISOLATED...SO NO WATCHES FOR FLASH FLOODING EXPECTED AND
WILL CONTINUE TO MENTION HEAVY RAIN...ISOLATED SVR IN THE HWO.
AS WE HEAD INTO LATE AFTERNOON AND EARLY EVENING THE LOW LVL FLOW
VEERS TO THE WEST AND THE GFS ESPECIALLY DRIES THE LEE SIDE OF THE
MOUNTAINS OUT WHILE HOLDING ONTO CONVECTION IN THE PIEDMONT...SO
WILL BE LEANING TOWARD LOWER POPS IN THE NEW RIVER VALLEY/FOOTHILLS
BY DUSK WHILE KEEPING THE WRN SLOPES AND PIEDMONT WITH HIGHER POPS.
OUR LOCAL WRF AND HRRR SHOWING THIS TO BE THE CASE AS WELL.
THINK WILL SEE SHOWERS AND STORMS SUBSIDE AGAIN BY LATE
EVENING/MIDNIGHT ESPECIALLY IN THE EAST WITH LOSS OF HEATING BUT
EXPECT THE THREAT OF SHOWERS TO REMAIN OVER THE WV/FAR SW VA MTNS
AHEAD OF THE FRONT AND CLOSER TO THE UPPER LEVEL SUPPORT.
FOR HIGHS TODAY WENT CLOSE TO THE ECMWF MOS AS THE GFS SEEMS TO WARM
AND NAM TOO COOL. LOOKING AT WARMER TEMPS WITH MORE SUN AND MIXING
BEFORE STORMS SET IN...WITH LOWER 80S WEST TO MID 80S TO NEAR 90
EAST.
TONIGHT REMAINS MUGGY WITH LOWS GENERALLY IN THE MID TO UPPER 60S
MOUNTAINS INTO THE LOWER 70S EAST.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EDT FRIDAY...
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THIS WEEKEND
INTO THE NEXT WORKWEEK AS A COLD FRONT MAKES ITS WAY ACROSS OUR
REGION. IN STICKING CLOSE WITH THE ECMWF MODEL SOLUTION...EXPECT TO
START SATURDAY OFF WITH THE COLD FRONT SITUATED NEAR THE INTERSTATE
81 CORRIDOR...WITH THE FRONT DRIFTING SLOWLY SOUTHWARD THROUGH THE
DAY...PERHAPS AIDED IN ITS PUSH BY OUTFLOW FROM AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS. BY SUNDAY MORNING...THE FRONT IS EXPECTED
TO ADVANCE INTO NORTH CAROLINA...WHERE IT WILL STALL AND BEGIN TO
WASH OUT ON MONDAY AS ANOTHER COLD FRONT APPROACHES FROM THE UPPER
MIDWEST.
DESPITE THE PASSAGE OF THE FRONT...WILL STILL SEE ABUNDANT LOW LEVEL
MOISTURE ACROSS OUR AREA AS DRIER AIR LINGERS TO OUR NORTH. MINOR
DISTURBANCES ALOFT WILL CONTINUALLY PASS ALONG THE FRONT FROM THE
WEST DURING THE WEEKEND...AND WILL TRIGGER ROUNDS OF SHOWERS AND
THUNDERSTORMS...MAINLY EACH AFTERNOON AND EVENING WHEN ENHANCED BY
DAYTIME HEATING. AS IN PREVIOUS NIGHTS...BELIEVE WE WILL SEE A
DRASTIC REDUCTION IN THE AMOUNT OF SHOWER ACTIVITY AFTER
SUNSET...ALTHOUGH CANNOT RULE A FEW SHOWERS DURING THE OVERNIGHTS.
WILL ALSO POINT OUT THE POSSIBILITY OF A FEW STRONG STORMS ON
SATURDAY AND SUNDAY...MORE SO SOUTH OF INTERSTATE 81. WHILE STRONG
THUNDERSTORM WINDS AND FREQUENT LIGHTNING WILL BE CONCERNS...THE
GREATEST CONCERN WILL BE FROM LOCALLY HEAVY RAIN AND THE POSSIBILITY
OF FLASH FLOODING. ANY FLOODING SHOULD REMAIN LOCAL IN SCALE...BUT
MAY DEVELOP QUICKLY IN STORMS WITH HIGH RAINFALL RATES...AND
ESPECIALLY IN LOCATIONS WITH SATURATED SOILS FROM RECENT HEAVY RAIN.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
AS OF 740 AM EDT FRIDAY...
FOG/LOW CLOUDS SHOULD CLEAR OUT THIS MORNING BY 14Z. SHOWERS AND
SOME STORMS MOVE TOWARD BLF/LWB AFTER 15Z AND MORESO IN THE
AFTERNOON. MODELS SHOWING MORE DEVELOPMENT IN THE EAST SO WILL
HAVE PREDOMINANT SHOWERS AT ALL SITES. SOME DIFFERENCES IN THE
ENDING TIME BUT THINK THE BCB/ROA AREA WILL CLEAR OUT SOONER WHILE
WINDS TURN TO THE WEST...WHILE DAN/LYH/BLF/LWB MAY SEE SHOWERS
LINGER INTO THE EVENING. KEPT VCTS IN THERE FOR NOW BUT CONFIDENCE
HIGH FOR MORE THUNDER TODAY GIVEN MORE SUN.
APPEARS FOG AND LOWER STRATUS COULD BE AN ISSUE AGAIN LATE FRIDAY
NIGHT.
THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE WEEKEND AND KEEPS THE
THREAT OF SHOWERS/STORMS AROUND. THE FRONT MAY SLIP SOUTH OF THE
AREA BY MONDAY INTO TUESDAY WITH STILL SOME THREAT OF SHOWERS OVER
THE SRN CWA FROM DAN-BCB-BLF.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
403 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONT IS EXPECTED TO MOVE SOUTHEAST THROUGH OUR AREA
THIS WEEKEND. HIGH PRESSURE OVER THE UPPER MIDWEST SHIFTS
SOUTHEAST THROUGH THE MID ATLANTIC BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM EDT FRIDAY...
RADARS QUIET THIS MORNING WITH ONLY ONE LONE SHOWER EXITING NRN
GREENBRIER COUNTY WITH MOST CONVECTION CENTERED WITH AND AHEAD OF A
SHORTWAVE AROUND CINCINNATI. THE 12Z ECMWF/00Z GFS ZERO IN ON THIS
SHORTWAVE AND PRECIP AND MAINLY SEE IT SHIFTING ENE INTO NRN WV
LATER THIS MORNING WITH A FEW SHOWERS MAKING ITS WAY INTO SE WV. FOR
EARLY TODAY WILL BE DEALING WITH AREAS OF FOG...LOCALLY DENSE AS IT
HAS CLEARED OUT SOME ASIDE FROM SOME HIGH CLOUDS. THIS FOG WILL BE
GOING AWAY AROUND 900 AM.
LOOKING AT WSW FLOW BACKING DURING THE DAY AND AFTER MIDDAY MODELS
SHOWING SOME LOW LVL CONVERGENCE ALONG THE BLUE RIDGE WITH A
PREFRONTAL TROUGH...WITH UPPER SUPPORT AND MAIN FRONT STAYING ACROSS
THE OHIO VALLEY INTO THE MID ATLANTIC. THINK COVERAGE WILL AGAIN
BECOME SCATTERED TO NUMEROUS OVER THE MOUNTAINS THEN SHIFT TO THE
PIEDMONT AS FLOW BACKS. WITH BETTER MIXING AND MORE SUNSHINE...THE
INSTABILITY AND CONVECTIVE TEMPS SUPPORT MORE THUNDER. STORMS WILL
BE HEAVY RAIN PRODUCERS AND MEAN FLOW SHOWING STORM MOVEMENT OF 10
TO 20 MPH. OVERALL THREAT FOR SVR THUNDERSTORMS AND FLASH FLOODING
REMAINS ISOLATED...SO NO WATCHES FOR FLASH FLOODING EXPECTED AND
WILL CONTINUE TO MENTION HEAVY RAIN...ISOLATED SVR IN THE HWO.
AS WE HEAD INTO LATE AFTERNOON AND EARLY EVENING THE LOW LVL FLOW
VEERS TO THE WEST AND THE GFS ESPECIALLY DRIES THE LEE SIDE OF THE
MOUNTAINS OUT WHILE HOLDING ONTO CONVECTION IN THE PIEDMONT...SO
WILL BE LEANING TOWARD LOWER POPS IN THE NEW RIVER VALLEY/FOOTHILLS
BY DUSK WHILE KEEPING THE WRN SLOPES AND PIEDMONT WITH HIGHER POPS.
OUR LOCAL WRF AND HRRR SHOWING THIS TO BE THE CASE AS WELL.
THINK WILL SEE SHOWERS AND STORMS SUBSIDE AGAIN BY LATE
EVENING/MIDNIGHT ESPECIALLY IN THE EAST WITH LOSS OF HEATING BUT
EXPECT THE THREAT OF SHOWERS TO REMAIN OVER THE WV/FAR SW VA MTNS
AHEAD OF THE FRONT AND CLOSER TO THE UPPER LEVEL SUPPORT.
FOR HIGHS TODAY WENT CLOSE TO THE ECMWF MOS AS THE GFS SEEMS TO WARM
AND NAM TOO COOL. LOOKING AT WARMER TEMPS WITH MORE SUN AND MIXING
BEFORE STORMS SET IN...WITH LOWER 80S WEST TO MID 80S TO NEAR 90
EAST.
TONIGHT REMAINS MUGGY WITH LOWS GENERALLY IN THE MID TO UPPER 60S
MOUNTAINS INTO THE LOWER 70S EAST.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EDT FRIDAY...
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THIS WEEKEND
INTO THE NEXT WORKWEEK AS A COLD FRONT MAKES ITS WAY ACROSS OUR
REGION. IN STICKING CLOSE WITH THE ECMWF MODEL SOLUTION...EXPECT TO
START SATURDAY OFF WITH THE COLD FRONT SITUATED NEAR THE INTERSTATE
81 CORRIDOR...WITH THE FRONT DRIFTING SLOWLY SOUTHWARD THROUGH THE
DAY...PERHAPS AIDED IN ITS PUSH BY OUTFLOW FROM AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS. BY SUNDAY MORNING...THE FRONT IS EXPECTED
TO ADVANCE INTO NORTH CAROLINA...WHERE IT WILL STALL AND BEGIN TO
WASH OUT ON MONDAY AS ANOTHER COLD FRONT APPROACHES FROM THE UPPER
MIDWEST.
DESPITE THE PASSAGE OF THE FRONT...WILL STILL SEE ABUNDANT LOW LEVEL
MOISTURE ACROSS OUR AREA AS DRIER AIR LINGERS TO OUR NORTH. MINOR
DISTURBANCES ALOFT WILL CONTINUALLY PASS ALONG THE FRONT FROM THE
WEST DURING THE WEEKEND...AND WILL TRIGGER ROUNDS OF SHOWERS AND
THUNDERSTORMS...MAINLY EACH AFTERNOON AND EVENING WHEN ENHANCED BY
DAYTIME HEATING. AS IN PREVIOUS NIGHTS...BELIEVE WE WILL SEE A
DRASTIC REDUCTION IN THE AMOUNT OF SHOWER ACTIVITY AFTER
SUNSET...ALTHOUGH CANNOT RULE A FEW SHOWERS DURING THE OVERNIGHTS.
WILL ALSO POINT OUT THE POSSIBILITY OF A FEW STRONG STORMS ON
SATURDAY AND SUNDAY...MORE SO SOUTH OF INTERSTATE 81. WHILE STRONG
THUNDERSTORM WINDS AND FREQUENT LIGHTNING WILL BE CONCERNS...THE
GREATEST CONCERN WILL BE FROM LOCALLY HEAVY RAIN AND THE POSSIBILITY
OF FLASH FLOODING. ANY FLOODING SHOULD REMAIN LOCAL IN SCALE...BUT
MAY DEVELOP QUICKLY IN STORMS WITH HIGH RAINFALL RATES...AND
ESPECIALLY IN LOCATIONS WITH SATURATED SOILS FROM RECENT HEAVY RAIN.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AS OF 140 AM EDT FRIDAY...
DEALING WITH A BIT OF FOG AND LOW CLOUDS EARLY THIS MORNING
ESPECIALLY AT ROA/LYH/BCB...WHERE IT RAINED. SEEMS THERE ARE
BREAKS IN THE LOWER CLOUDS TO ALLOW FOR FOG AND LOW STRATUS...AND
CONFIDENCE HIGH ENOUGH TO FORECAST IFR OR WORSE AT ALL TAF SITES
BUT BLF WHERE THEY SHOULD DROP TO MVFR. ANY SHOWERS SHOULD STAY
MAINLY NORTH OF LWB/BLF BUT KEPT VCSH AT LWB GIVEN PROXIMITY OF
UPPER SHORTWAVE.
FOG/LOW CLOUD SHOULD CLEAR OUT BY MID MORNING BUT WILL BE BKN AT
MVFR/VFR THRU THE DAY. WITH GOOD MIXING FROM A WSW WIND SHOULD SEE
MORE SUNSHINE BY THE AFTERNOON AND MODELS ADVERTISING GOOD THREAT
OF SHOWERS AND STORMS. HAVE ALLOWED FOR VCTS AT ALL TAF SITES WITH
LIGHT TO MODERATE SHOWERS. HOWEVER...WILL KEEP VSBYS/CIGS VFR.
THE CONVECTION WEAKENS/ENDS AROUND 00Z SAT EXCEPT LINGERING
SHOWERS ACROSS THE LWB CORRIDOR DUE TO ANOTHER SHORTWAVE PUSHING
ACROSS NRN WV.
APPEARS FOG AND LOWER STRATUS COULD BE AN ISSUE AGAIN FRIDAY
NIGHT.
THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE WEEKEND AND KEEPS THE
THREAT OF SHOWERS/STORMS AROUND. THE FRONT MAY SLIP SOUTH OF THE
AREA BY MONDAY INTO TUESDAY WITH STILL SOME THREAT OF SHOWERS OVER
THE SRN CWA FROM DAN-BCB-BLF.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...WP
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1123 AM PDT Fri Aug 9 2013
.SYNOPSIS...
QUIET WEATHER THIS MORNING WILL BE FOLLOWED BY INCREASED CLOUDS
AND A THREAT OF PRECIPITATION THIS AFTERNOON. FROM THIS EVENING
THROUGH MUCH OF NEXT WEEK A PERSISTENT WEATHER PATTERN WILL BRING
A CHANCE OF THUNDERSTORMS EACH DAY WITH TEMPERATURES REMAINING
SEASONABLY WARM.
&&
.DISCUSSION...
This afternoon...The east-west band of elevated convection...which
crossed the WA/ID border earlier this morning continues to drift
slowly northward...away from parent upper low. Cloud tops have
generally warmed over the past couple hours and suspect that trend
will continue as it usually does with elevated convection this
time of day. The threat of elevated convection will wane through
early-afternoon...however if the HRRR model solution is
correct...the threat will perk up by mid-afternoon. RUC forecasts
show the greatest CAPEs this afternoon developing over the central
Idaho Panhandle and the dying band of elevated convection could
be the driving trigger. Although CAPEs rise across the entire
forecast area this afternoon...there will be a decent amount of
convective capping or CIN to overcome and given the positioning of
the upper level low this may not be accomplished. Pops have been
lowered for most locations aside from the central Panhandle and
along the Cascades. Remainder of forecast left generally as
is...but decreased cloud cover a bit. Afternoon temps still look
warm for this time of year with highs generally in the 90s. fx
&&
.AVIATION...
18Z TAFS: VFR conditions expected at all sites through the period.
Only weather of consequence was band of elevated instability and a
few Accas clouds near KPUW...KLWS...and KMWH moving slowly
northward. Cloud tops will likely be too low to produce
lightning...but there is a remote chance. Looks like thunder
chances will increase this afternoon but most should keep clear of
TAF sites. Biggest threat will occur over the central ID
Panhandle. The threat will increase again late this evening or
overnight as a weak shortwave approaches from the south.
Confidence is low that any will directly hit any forecast
site...however it was at least worth a mention of VCTS between
06-12z or so. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 93 66 91 65 88 64 / 10 20 20 50 50 40
Coeur d`Alene 91 61 90 60 88 58 / 10 20 20 50 50 40
Pullman 92 56 89 55 87 52 / 20 30 20 40 40 30
Lewiston 99 66 96 65 94 64 / 20 30 20 40 40 30
Colville 96 57 93 57 92 56 / 10 20 20 50 50 40
Sandpoint 89 57 88 55 86 54 / 10 20 30 40 50 50
Kellogg 89 59 88 58 86 57 / 20 30 20 60 60 50
Moses Lake 97 65 95 64 93 61 / 10 30 40 50 30 20
Wenatchee 96 70 94 69 93 67 / 10 30 60 60 50 40
Omak 98 66 96 64 95 62 / 10 30 40 50 70 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WA... Red Flag Warning from 5 PM this afternoon to 11 PM PDT Sunday
for East Washington Central Cascade Mountains (Zone 682)-
East Washington Central Cascade Valleys (Zone 677)-East
Washington North Cascades (Zone 685)-East Washington
Northern Columbia Basin (Zone 673)-East Washington
Okanogan/Methow Valleys (Zone 684)-East Washington Palouse
and Spokane Area (Zone 674)-East Washington South Central
Cascade Mountains (Zone 680)-East Washington South Central
Cascade Valleys (Zone 676).
Flash Flood Watch from Saturday morning through Sunday evening
for East Slopes Northern Cascades-Waterville Plateau-
Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
950 PM CDT SAT AUG 10 2013
.UPDATE...OVERNIGHT INTO TOMORROW MORNING
ISSUED AT 949 PM CDT SAT AUG 10 2013
CONTINUE TO MONITOR CONVECTIVE TRENDS FOR THE OVERNIGHT PERIOD AS
A SYSTEM MOVES INTO THE REGION. CURRENTLY...SHOWERS HAVE FIZZLED
ACROSS SOUTHERN MINNESOTA AS AN INITIAL MID LEVEL SHORTWAVE TROUGH
HAS WEAKENED AS IT HAS TRACKED EAST TOWARD THE MISSISSIPPI RIVER.
THE STRONGER LIFT IS STILL WELL BACK TO THE WEST ALONG TWO
SEPARATE FEATURES...A FRONTOGENETIC BAND IN SOUTHEAST SOUTH DAKOTA
AND A MID LEVEL SHORT WAVE TROUGH IN NORTH DAKOTA. THE PAST FEW
RUNS OF THE HRRR AND RAP HAVE BROUGHT SOME OF THE SCATTERED LIGHT
RAIN SHOWERS INTO THE REGION THROUGH THE NEXT 6 HOURS OR SO...BUT
DO NOT EXPECT MUCH IF ANYTHING OUT OF THESE. THE MAIN SHOW WILL
COME IN INITIALLY WITH THE BAND OF FRONTOGENESIS THAT HAS HELPED
CONVECTION DEVELOP IN SOUTHEAST SOUTH DAKOTA ALONG A SURFACE WARM
FRONT. THIS BAND IS GOING TO VERY SLOWLY DRIFT EAST OVERNIGHT AND
MAY NOT REACH THE REGION UNTIL LATER IN THE MORNING. THIS LEADS TO
SOME QUESTIONS ABOUT HOW MUCH WILL BUILD IN AHEAD OF IT AS LOW
LEVEL MOISTURE TRANSPORT DOES TRY TO INCREASE FROM THE SOUTHWEST.
BASED ON THIS...WILL HAVE TO BACK OFF ON THE PRECIPITATION CHANCES
A LITTLE OVERNIGHT BUT WILL KEEP THEM ON THE HIGHER SIDE TOMORROW
MORNING AND AFTERNOON.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 347 PM CDT SAT AUG 10 2013
MAIN FORECAST CONCERNS ARE ON SHOWERS AND THUNDERSTORMS LATE TONIGHT
THROUGH SUNDAY NIGHT.
LATEST WATER VAPOR IMAGERY SHOWED WEST/NORTHWEST FLOW ALOFT ACROSS
THE REGION. TWO MAIN SHORTWAVES TO FOCUS ON OVER THE NEXT 36
HOURS...A LEADING WAVE OVER EASTERN SOUTH DAKOTA AND
ANOTHER VIGOROUS SHORTWAVE OVER SOUTHERN SASKATCHEWAN DIGGING
SOUTHEAST INTO WESTERN NORTH DAKOTA. SHOWERS AND EMBEDDED
THUNDERSTORMS WERE OCCURRING OVER EASTERN AND NORTH CENTRAL SOUTH
DAKOTA. AN ADDITIONAL AREA OF SHOWERS AND STORMS WERE ERUPTING
OVER EXTREME NORTHWEST MONTANA AND NORTHWESTERN NORTH DAKOTA.
THE SHORTWAVE OVER EASTERN SOUTH DAKOTA WILL MAKE ITS WAY EAST INTO
THE FORECAST AREA LATE THIS EVENING. MEANWHILE...THE NORTHERN
SHORTWAVE WILL BE PUSHING SOUTHEAST INTO THE REGION AS A 250MB JET
STREAK INTENSIFIES AND SAGS SOUTH...PLACING THE RIGHT ENTRANCE REGION
OVER CENTRAL MINNESOTA/INTO CENTRAL WISCONSIN. A FRONTAL BOUNDARY
WILL ORIENT ITSELF RIGHT ALONG THE INTERSTATE 90 CORRIDOR LATE THIS
EVENING INTO THE OVERNIGHT HOURS AND PROVIDE THE FOCUS FOR SHOWER
AND THUNDERSTORMS DEVELOPMENT. THINKING A COMPLEX OF SHOWERS AND
STORMS SHOULD INTENSIFY OVER SOUTHEAST SOUTH DAKOTA/SOUTHWEST
MINNESOTA/NORTHWEST IOWA...THEN PUSH EAST INTO THE FORECAST AREA LATE
TONIGHT INTO EARLY SUNDAY MORNING. THERE IS A GENERAL INCREASE IN
MOISTURE TRANSPORT INTO THE FRONT OVERNIGHT INTO SATURDAY
MORNING AND A RATHER IMPRESSIVE INCREASE IN FRONTOGENESIS
ESPECIALLY IN THE NAM. WHILE THE NAM APPEARS TO BE CONTAMINATED BY
SOME CONVECTION...THINKING IT HAS THE RIGHT IDEA WITH AN INCREASE
IN FRONTOGENESIS IN THE 9 TO 15Z TIME FRAME. ADDITIONAL SHOWER AND
POSSIBLY SCATTERED THUNDERSTORM DEVELOPMENT IS LIKELY AHEAD OF THE
MAIN COMPLEX OF STORMS WORKING INTO THE AREA FROM THE WEST
TONIGHT. PLAN ON SHOWERS AND STORMS TO SPREAD INTO AREAS WEST OF
THE MISSISSIPPI RIVER AFTER MIDNIGHT THEN WORKING EAST INTO
CENTRAL AND SOUTHWEST WISCONSIN AROUND DAYBREAK SUNDAY MORNING.
SOME HEALTHY RAINFALL AMOUNTS IN STORE FOR LOCATIONS ALONG AND
SOUTH OF INTERSTATE 90...WHERE RAINFALL COULD TOTAL 1/2 INCH TO
NEARLY ONE INCH DEPENDING ON EXACTLY WHERE THE BAND SETS UP. THE
BAND OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL PERSIST OVER
THE AREA THROUGH THE MORNING HOURS AND INTO SUNDAY AFTERNOON THEN
SHOULD GRADUALLY START TO SHIFT SOUTHWARD. THE ABUNDANT CLOUD
COVER AND ONGOING SHOWERS AND STORMS WILL HELP LIMIT HOW MUCH
INSTABILITY BUILDS THROUGH THE DAY AND WILL ALSO ACT TO KEEP
TEMPERATURES ON THE COOL SIDE WITH HIGHS ONLY IN THE LOWER 70S. IN
FACT...LOCATIONS RIGHT UNDER THE BAND WILL STRUGGLE TO GET OUT OF
THE 60S. IF THERE HAPPENS TO BE A BREAK IN THE ACTIVITY FROM MID
SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON AND ENOUGH INSTABILITY
CAN BUILD ALONG THE FRONTAL BOUNDARY THERE IS AN OUTSIDE CHANCE OF
A STRONGER THUNDERSTORM OVER NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. THE OVERALL PROBABILITY OF THIS OCCURRING OVER THESE
AREA APPEARS LOW AT THIS TIME...BUT WILL HAVE TO KEEP A CLOSE EYE
ON CLOUD/PRECIPITATION TRENDS. FORECAST MODELS ATTEMPT TO INCREASE
THE INSTABILITY RIGHT ALONG THE BOUNDARY SUNDAY AFTERNOON OVER
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN WITH MLCAPE VALUES
CLIMBING TO AROUND 1100 J/KG. 0-6KM BULK SHEAR VALUES HOVERING
AROUND 40 KTS WOULD BE SUFFICIENT FOR A SEVERE STORM OR TWO. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS. ALSO...WILL
HAVE TO KEEP A CLOSE EYE ON ANY STORMS THAT WOULD DEVELOP RIGHT
ALONG THE BOUNDARY WHERE SHEAR PROFILES COULD POSSIBLY SUPPORT A
TORNADO. ALL OF THIS IS CONDITIONAL ON AFTERNOON DESTABILIZATION.
ONGOING SHOWERS AND STORMS WILL GRADUALLY TAPER OFF SUNDAY EVENING
INTO LATE SUNDAY NIGHT AS THE BOUNDARY SLIPS SOUTH AND THE JET
STREAK WEAKENS SLIGHTLY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 347 PM CDT SAT AUG 10 2013
SHOWERS AND STORMS TAPER OFF SUNDAY NIGHT THEN ANOTHER TROUGH DIVES
SOUTH OUT OF CANADA AND INTO THE UPPER MISSISSIPPI RIVER VALLEY
MONDAY AFTERNOON INTO TUESDAY. THIS FEATURE MAY GENERATE A FEW
SHOWERS AND ISOLATED STORMS AS IT MOVES THROUGH...PARTICULARLY OVER
NORTH CENTRAL WISCONSIN. CANADIAN HIGH PRESSURE THEN BUILDS INTO THE
AREA TUESDAY THROUGH THURSDAY WITH DRY AND QUIET CONDITIONS
EXPECTED. WILL HAVE TO KEEP A CLOSE EYE ON THE POTENTIAL FOR VALLEY
FOG WITH THE HIGH OVERHEAD AND LIGHT WINDS. PLAN ON SEASONABLY COOL
TEMPERATURES THROUGH THE THE WEEK WITH HIGHS IN THE MID TO UPPER
70S. RAIN CHANCES RETURN THURSDAY NIGHT THROUGH FRIDAY NIGHT AS
WEAK SHORTWAVES MOVE THROUGH THE REGION. HOWEVER...LATEST MODEL
GUIDANCE HINTS AT THIS TIME FRAME POSSIBLY ENDING UP DRY. IF MODEL
TRENDS CONTINUE PRECIPITATION CHANCES MAY NOT BE NEEDED DURING
THIS TIME FRAME WITH THE SURFACE HIGH HOLDING STRONG FROM THE
MIDDLE OF NEXT WEEK ALL THE WAY INTO NEXT WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 640 PM CDT SAT AUG 10 2013
THE MAIN FOCUS GOING INTO TOMORROW IS WITH THE RAIN CHANCES AND
WHETHER ANY MVFR/IFR CONDITIONS WILL FORM. AN INITIAL BAND OF
SHOWERS HAS DEVELOPED IN SOUTHWEST MINNESOTA AND WILL TRACK TO THE
EAST THIS EVENING. THE CONDITIONS BECOME LESS FAVORABLE FOR THE
SHOWERS TO HOLD TOGETHER AS IT TRACKS TO THE EAST...SO EXPECT
THAT IT WILL CONTINUE TO DIMINISH IN COVERAGE AS IT REACHES RST.
STILL COULD HAVE A FEW SHOWERS IN SOUTHEAST MINNESOTA...SO HAVE
PUT IN SOME VCSH FOR LATER THIS EVENING.
THE MAIN SHOW COMES IN OVERNIGHT INTO TOMORROW MORNING AS A TROUGH
DIGS DOWN FROM THE DAKOTAS. RAIN IS EXPECTED TO BECOME FAIRLY
WIDESPREAD AROUND DAYBREAK...BUT THE QUESTION IS WHERE THIS BAND
OF RAIN WILL FORM AND WHETHER IT WILL BE IN AT THE TAF SITES. IF
IT DOES LINE UP ALONG A RST/LSE LINE...THEN THERE COULD BE SOME
MVFR OR IFR CONDITIONS THAT COME ALONG WITH IT. THERE DOES NOT
APPEAR TO BE MUCH IN THE WAY OF INSTABILITY IN PLACE AS THE RAIN
FALLS...SO AM NOT EXPECTING MUCH IN THE WAY OF LIGHTNING WITH THE
RAIN. CONDITIONS SHOULD IMPROVE INTO THE AFTERNOON AS THE FOCUS
SHIFTS SOUTH ALONG THE FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS TUCSON AZ
205 AM MST SUN AUG 11 2013
.SYNOPSIS...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS FROM TUCSON
EASTWARD AND SOUTHWARD THIS AFTERNOON AND THIS EVENING. DECREASING
CHANCES FOR THUNDERSTORMS WILL THEN OCCUR MONDAY THROUGH WEDNESDAY
AS DEEPER MOISTURE MOVES EAST OF THE AREA. SCATTERED AFTERNOON AND
EVENING THUNDERSTORMS WILL THEN PREVAIL MAINLY EAST OF TUCSON DURING
THE LATTER PART OF THE WEEK.
&&
.DISCUSSION...PRONOUNCED MOISTURE GRADIENT ACROSS SE AZ EARLY THIS
MORNING...WITH DEWPOINTS VALID 09Z RANGING FROM THE MID 50S-MID 60S
ERN SECTIONS TO THE LOWER-MID 30S FROM TUCSON WWD. BLENDED TOTAL
PRECIP WATER IMAGERY ALSO DEPICTED THE DISTINCT MOISTURE GRADIENT
NICELY...WITH VALUES RANGING FROM NEARLY 1.20 INCHES ACROSS SE
COCHISE COUNTY TO ABOUT 0.60 INCH ACROSS FAR WRN PIMA COUNTY.
11/00Z NAM/GFS/ECMWF REMAINED SIMILAR VERSUS PREVIOUS SOLUTIONS IN
MOVING THE MOISTURE GRADIENT FURTHER WWD TODAY...AND GENERALLY
BISECTING THIS FORECAST AREA FROM TUCSON EWD WITH DEEPER MOISTURE
FROM MUCH DRIER AIR ACROSS WRN SECTIONS. 11/06Z RUC HRRR DEVELOPS
PRECIP ECHOES BY 18Z ACROSS THE CATALINA/RINCON/SANTA RITA MTNS NEAR
TUCSON...AS WELL AS ACROSS MUCH OF THE REST OF SANTA CRUZ COUNTY...
AND ACROSS THE HIGHER TERRAIN OF SRN GRAHAM/COCHISE COUNTIES.
FOR TODAY...NO SIGNIFICANT ADJUSTMENTS WERE MADE TO THE INHERITED
GRIDDED DATA POP FIELDS. THUS...SCATTERED SHOWERS/TSTMS FROM TUCSON
EWD/SWD THIS AFTERNOON AND THIS EVENING WITH DRY CONDITIONS ACROSS
WRN PIMA COUNTY. THERE SHOULD BE ENOUGH MOISTURE TO JUSTIFY A SLIGHT
CHANCE OF SHOWERS/TSTMS LATE TONIGHT ACROSS THE WHITE MOUNTAINS WITH
DRY CONDITIONS ELSEWHERE.
MONDAY-WEDNESDAY...DEEPER MOISTURE IS PROGGED TO MOVE WELL EAST AND
SOUTH OF SE AZ AS GENERALLY SWLY FLOW ALOFT PREVAILS. ISOLATED-
SCATTERED AFTERNOON/EVENING TSTMS MOSTLY EAST OF TUCSON MONDAY...
THEN ISOLATED AFTERNOON/EVENING TSTMS TUE-WED MAINLY NEAR THE
MOUNTAINS OF GREENLEE/GRAHAM/COCHISE COUNTIES WITH DRY CONDITIONS
ELSEWHERE.
THURSDAY-SATURDAY...UPPER RIDGE TO AMPLIFY OVER THE WRN CONUS AS
HIGH PRESSURE ALOFT BECOMES CENTERED OVER THIS FORECAST AREA. SOME
INCREASE IN MOISTURE IS PROGGED TO OCCUR THIS PERIOD. HOWEVER...
INCREASED MID-LEVEL TEMPS MAY BE A LIMITING FACTOR FOR CONVECTIVE
DEVELOPMENT. FOR CONTINUITY...HAVE MAINTAINED ISOLATED-SCATTERED
AFTERNOON AND EVENING SHOWERS/TSTMS MAINLY FROM TUCSON EWD/SWD.
HIGH TEMPS THIS WEEK WILL AVERAGE ABOUT 2-5 DEGS F ABOVE NORMAL.
&&
.AVIATION...TSRA/SHRA TO DEVELOP FROM KTUS VICINITY EWD/SWD AROUND
17Z-18Z THIS MORNING. SCT TSRA/SHRA TO THEN OCCUR FROM KTUS EWD/SWD
THIS AFTERNOON AND THIS EVENING. EXPECT MVFR CONDITIONS AND WIND
GUSTS TO AROUND 45 KTS WITH THE STRONGEST TSRA. BULK OF PRECIP TO BE
LIMITED TO THE WHITE MTNS NE OF KSAD 06Z-12Z MONDAY. OTHERWISE...
MOSTLY CLEAR SKIES WEST OF KTUS WITH SCT-OVC CLOUDS MOSTLY AT 8-12K
FT AGL FROM KTUS EWD/SWD THRU EARLY MONDAY MORNING OR 12/12Z.
SURFACE WIND GENERALLY LESS THAN 10 KTS THRU EARLY MONDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED THUNDERSTORMS WILL OCCUR FROM TUCSON
EASTWARD AND SOUTHWARD THIS AFTERNOON AND THIS EVENING. THERE WILL
BE DECREASING CHANCES FOR THUNDERSTORMS MONDAY THROUGH WEDNESDAY AS
DEEPER MOISTURE MOVES EAST OF THE AREA. THEREAFTER...ISOLATED TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL PREVAIL THURSDAY
THROUGH SATURDAY. OTHERWISE...NORMAL DIURNAL WIND TRENDS WILL OCCUR
THIS WEEK...WITH OCCASIONAL GUSTS DURING THE AFTERNOON AND EARLY
EVENING HOURS DUE TO STRONG DAYTIME HEATING.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
BF
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
133 AM EDT SUN AUG 11 2013
.SYNOPSIS...
ISSUED AT 133 AM EDT SUN AUG 11 2013
HIGH PRESSURE WILL MAINTAIN DRY CONDITIONS THROUGHOUT THE DAY
TODAY. NEXT CHANCE OF SHOWERS AND THUNDERSTORMS WILL ARRIVE IN THE
EARLY HOURS OF MONDAY MORNING AS A LOW PRESSURE SYSTEM MOVES
THROUGH THE REGION.
&&
.UPDATE...
ISSUED AT 827 PM EDT SAT AUG 10 2013
DEPARTING SHEARED VORTICITY MAXIMUM ACROSS THE NORTHERN GREAT LAKES
AND DIURNAL WANING OF SURFACE BASED INSTABILITY WILL RESULT IN
CONTINUED DOWNWARD TREND OF ISOLATED SHOWERS ACROSS THE EXTREME
SOUTHEAST EARLY THIS EVENING. WATER VAPOR IMAGERY EARLY THIS
EVENING AND 22Z RAP INITIALIZATION DOES SEEM TO SUGGEST PRESENCE OF
WEAK UPSTREAM SHORT WAVE ACROSS NORTHWEST ILLINOIS. APPROACH OF
THIS WEAK WAVE LATE THIS EVENING AND CONTINUED WEAK SFC
CONVERGENCE WITH LINGERING INVERTED TROUGH TYPE FEATURE COULD
ALLOW FOR AN ISOLATED SHOWER TO DEVELOP ACROSS EASTERN PORTIONS OF
THE AREA. HOWEVER...HAVE LARGELY MAINTAINED PREVIOUS FORECAST
TRENDS TO MOSTLY CLEAR/PARTLY CLOUDY CONDITIONS WITH CLOUDS
PERSISTING OVER THE NEXT FEW HOURS...ESPECIALLY IN VICINITY OF
AFOREMENTIONED SFC CONVERGENCE ZONE FROM ROUGHLY ANGOLA TO SOUTH
OF FORT WAYNE. WILL ALSO NEED TO MONITOR TRENDS THROUGH REMAINDER
OF EVENING FOR SOME PATCHY FOG POTENTIAL...PARTICULARLY ACROSS
SOUTHEAST PORTIONS OF THE AREA WHERE LOW LEVEL MOISTURE WILL
LIKELY LINGER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 447 PM EDT SAT AUG 10 2013
WK LL CVRG BNDRY IN ASSOCN/W SHEARING DISTURBANCE ALOFT AND IN
CONJUNCTION W/SUFFICIENT SFC BASED DESTABILIZATION ENOUGH TO SPARK A
NARROW BKN BAND OF SHRA ALG A HUNTING TO DEFIANCE LINE THIS AFTN.
ACTIVITY LIKELY NR PEAK AND XPC A GENERAL DOWNTREND THROUGH 23Z.
OTRWS SFC RIDGING TO EXPAND EWD ACRS THE GREAT LAKES IN BEHIND
SECONDARY WK CDFNT PASSING THROUGH THE LAKES TONIGHT YIELDING A
PLEASANTLY COOL AND DRY SUNDAY.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 447 PM EDT SAT AUG 10 2013
A WEAK UPPER LEVEL TROF AND ACCOMPANYING COLD FRONT WILL MOVE SOUTH
ACROSS THE WESTERN GREAT LAKES REGION LATE SUNDAY NIGHT...AND TOWARD
THE OHIO RIVER MONDAY NIGHT. HAVE EXPANDED SHOWER/STORM CHANCES LATE
SUNDAY NIGHT OVER NORTHERN AREAS AS A SURGE OF LOW LEVEL THETA E
REACHES FAR SOUTHERN LOWER MICHIGAN INTO NRN INDIANA. PREFER THE
ECMWF HANDLING THIS SYSTEM...WITH CONVECTIVE DEVELOPMENT IN THE AREA
OF THIS LOW LEVEL THETA E CONVERGENCE OVER LOWER MICHIGAN...AND THEN
MONDAY NIGHT WITH REDEVELOPMENT ALONG THE THE FRONT OVER NRN INDIANA
INTO NW OHIO. HAVE RAISED SHOWER/STORM CHANCES ACCORDINGLY LATE
SUNDAY NIGHT. HAVE ALSO WENT WITH A LITTLE SLOWER FRONTAL PASSAGE
MONDAY NIGHT...WITH SOME LINGERING SHOWERS POSSIBLE OVER SOUTHEAST
AREAS LATE MONDAY NIGHT. NOT OPTIMAL SEVERE STORM PARAMETERS WITH
RELATIVELY LOW CAPES AND LOW LEVEL WINDS MORE UNIDIRECTIONAL.
HOWEVER...THE RIGHT ENTRANCE REGION OF A DEPARTING 80 JET MAX MAY BE
SUFFICIENT TO PRODUCE SOME STRONG STORMS. OTHERWISE...KEPT THE
FORECAST DRY FROM TUESDAY THROUGH THE END OF THE FORECAST PERIOD
SATURDAY. HAVE BLENDED THE GFS AND ECMWF RUNS OVER THIS PERIOD...
WITH THE THERMAL TROF REMAINING OVER THE AREA LONGER THAN EARLIER
MODEL RUNS INDICATED. AS A RESULT...HAVE TRENDED MOST HIGH AND LOW
TEMPS DOWN STARTING WEDNESDAY NIGHT. THIS PATTERN IS MORE LIKE
SEPTEMBER THAN AUGUST...WITH HIGHS IN THE MID TO UPPER 70S AND LOWS
MAINLY IN THE 50S. THE GFS MEAN ENSEMBLE MOS APPEARS ON TRACK...SO
HAVE ATTEMPTED TO FOLLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 133 AM EDT SUN AUG 11 2013
SURFACE HIGH PRESSURE WILL MAINTAIN LIGHT WINDS AND VFR CONDITIONS
FOR MUCH OF THE FORECAST PERIOD. RESIDUAL NEAR SURFACE MOISTURE
AROUND KFWA MAY SUPPORT SOME BRIEF BR DEVELOPMENT LATER THIS
MORNING BUT AREA DEWPOINTS ARE FAIRLY LOW WITH NO VIS REDUCTION AS
OF YET. WILL MAINTAIN MVFR MENTION BUT ANY PATCHY FOG THAT
DEVELOPS SHOULD BE SHALLOW WITH LIMITED AVIATION IMPACT. ALONG
WITH SOME SCT DIURNAL CU...MIDLEVEL CLOUDS WILL BE INCREASING
TOWARD THE END OF THE DAY AS THE NEXT SYSTEM APPROACHES BUT
CEILINGS EXPECTED TO REMAIN WELL WITHIN VFR CATEGORY THROUGH THE
PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...KG/AGD
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...AGD
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
317 AM CDT SUN AUG 11 2013
.SYNOPSIS...
ISSUED AT 305 AM CDT SUN AUG 11 2013
06Z SFC ANALYSIS HAS A WEAK LOW NEAR KICR WITH A STATIONARY FRONT
SOUTHEAST INTO WESTERN IOWA. A WEAK BOUNDARY RAN FROM SOUTHEAST
SOUTH DAKOTA INTO NORTHERN IOWA. DEW POINTS WERE IN THE 50S ACROSS
THE GREAT LAKES WITH 60S IN THE PLAINS AND 70S ACROSS THE DEEP SOUTH
AND OHIO VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
THE MCS AND LIFT TOOLS WHEN APPLIED TO TRENDS IN THE RAP AND OTHER
MODELS SUGGEST A MAJORITY OF THE PRECIPITATION WILL REMAIN NORTH OF
THE CWFA THROUGH MID DAY WITH SOME SHOWERS BRUSHING THE NORTHERN
CWFA IN THE HIGHWAY 20 CORRIDOR. RECENT TRENDS WITH THE RAP SUGGEST
PRECIPITATION MAY NOT BEGIN ENTERING THE NORTHERN CWFA UNTIL AROUND
SUNRISE.
PRECIPITATION SHOULD WANE DURING THE LATE MORNING AND EARLY
AFTERNOON BEFORE RE-DEVELOPING THIS AFTERNOON HOURS DURING MAX
HEATING. ANY PRECIPITATION IN THE HWY 20 CORRIDOR WILL EXPAND
SOUTHWARD TO HWY 30 AND EVENTUALLY TO I-80 BY LATE AFTERNOON.
TONIGHT...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL BE ACROSS
ROUGHLY THE NORTHERN HALF OF THE CWFA DURING THE EVENING BEFORE
SLOWLY SPREADING SOUTH AFTER MIDNIGHT. THE EXTREME SOUTHERN PART OF
THE CWFA CURRENTLY LOOKS TO BE DRY BOTH TODAY AND TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN AUG 11 2013
RAIN CHANCES LINGER EARLY IN THE WEEK THEN MAINLY DRY AND PLEASANT
REST OF THE PERIOD WITH NEAR TO BELOW NORMAL TEMPS.
MON-MON NGT... SURFACE AND 850 MB COLD FRONTS WILL GRADUALLY SLIDE
THROUGH THE AREA AS AN UPPER LEVEL TROUGH MOVES INTO THE GREAT
LAKES. 850 MB BOUNDARY IS SUGGESTED TO BE PRIMARY PCPN MECHANISM
DUE TO BETTER CONVERGENCE WITH SCATTERED ELEVATED SHOWERS AND
ISOLD STORMS MAINLY NORTH OF I-80 MON AM SLIDING SOUTHEAST IN THE
PM. CONVERGENCE ALONG SURFACE FRONT FAIRLY WEAK BUT IF SUFFICIENT
HEATING INTO THE MID 80S THEN CAPPING INVERSION SHOULD WEAKEN AND
JUST ENOUGH CONVERGENCE TO ALLOW SCATTERED STORMS TO DEVELOP FROM
MID PM TO EARLY EVE MAINLY JUST S/SE OF QUAD CITIES. ENVIRONMENT
LOOKS LIKE FAIRLY WEAK TO MARGINAL SHEAR (0-6KM BULK SHEAR 20-25 KTS)
AND MODERATE INSTABILITY (MUCAPES 1500-2000+ J/KG)... THUS MARGINAL
ISOLD PULSE TYPE STORMS SUGGESTED WITH SOME SMALL HAIL AND DOWNBURST
WINDS POSSIBLE. BANKING ON ANY PCPN MAINLY SCATTERED AND ENOUGH
BREAKS IN CLOUDS TO YIELD WIDESPREAD 80S FOR HIGHS WITH THE WARMEST
READINGS ACROSS THE SOUTHERN CWA. RAIN CHCS LINGER MON EVE ACROSS THE
SOUTH...THEN HIGH PRESSURE RIDGE BEGINS TO BUILD IN OVRNGT BRINGING IN
DRIER AIR. LOWS MON NGT COOLEST NORTH WHERE SOME 50S WHILE 60S ARE
LIKELY ELSEWHERE.
TUE-TUE NGT... UKMET IS AN OUTLIER HOLDING UP MID LEVEL BAROCLINIC
ZONE ACROSS SOUTHERN CWA AND GENERATING SOME ADDITIONAL PCPN ON TUE.
HAVE SIDED TOWARD CONSENSUS FCST WITH CONTINUED DRY AND COOL
ADVECTION WITH STRENGTHENING NORTHWEST FLOW ALOFT AND INCOMING SURFACE
RIDGE SHUNTING BAROCLINIC ZONE AND PCPN PROCESSES SOUTH/WEST OF THE
CWA. HIGHS TUE RANGING FROM SOME MID 70S NORTH TO LOWER 80S SOUTH WITH
PT-MOSUNNY SKIES. CONTINUED LOWERING OF DEWPTS MAINLY INTO THE 50S
COUPLED WITH N/NE WINDS 5-10 MPH SHOULD MAKE FOR A REAL NICE AND
VERY COMFORTABLE DAY FOR OUTDOOR ACTIVITIES. COOL CONDITIONS EXPECTED
TUE NGT WITH CLEARING SKIES AND LIGHT WINDS ALLOWING FOR WIDESPREAD
LOWS IN THE 50S.
WED-SAT...FLOW ALOFT WILL REMAIN NORTHWEST WITH LARGE EXPANSE OF HIGH
PRESSURE AT THE SURFACE SLOWLY SHIFTING FROM THE UPPER MIDWEST INTO
THE OH VLY. RESULT WILL BE A PROLONGED PERIOD OF FANTASTIC WX FEATURING
LOW HUMIDITY...LIGHT WINDS...MAINLY CLEAR SKIES AND SLIGHTLY BELOW
NORMAL TEMPS WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S AND LOWS IN
THE 50S TO AROUND 60F.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
VFR WX IS EXPECTED THROUGH 06Z/12. THE POSSIBILITY DOES EXIST THAT
KDBQ MAY SEE VCSH OR EVEN VCTS IN THE 12Z/11 TO 18Z/11 TIME FRAME.
AFT 18Z/11 DIURNAL CONVECTION WILL DEVELOP THAT MAY AFFECT A TAF
SITE WITH A BRIEF PERIOD OF MVFR CONDITIONS. AFT 06Z/12 THE
POSSIBILITY DOES EXIST FOR POCKETS OF MVFR VSBYS DEVELOPING ACROSS
EASTERN IOWA AND NORTHERN ILLINOIS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
325 AM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO SQUIRRELLY IN THIS PATTERN TO BITE
ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE RUN.
DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A THREAT
FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 210 AM EDT SUN AUG 11 2013
THE LAST OF THE SHOWERS AND FORMER THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH FAR EAST KENTUCKY EARLY THIS MORNING. THE LOWER CIGS AND
VSBY WILL BE HIT AND MISS THROUGH THE NIGHT AND WILL PROBABLY NOT
BLANKET THE ENTIRE AREA. AN IMPROVEMENT TO VFR SHOULD TAKE PLACE BY
LATE MORNING ON SUNDAY. SHOWERS WILL BE POSSIBLE AT JUST ABOUT ANY
POINT THROUGH THE DAY ON SUNDAY. WINDS WILL BE LIGHT AND VARIABLE
DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EDT SUN AUG 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WRLY FLOW THROUGH THE NRN
GREAT LAKES ON THE SRN FLANK OF A MID/UPPER LEVEL TROUGH EXTENDING
FROM HUDSON BAY TO NEW FOUNDLAND. A WELL-DEFINED UPSTREAM SHORTWAVE
TROUGH LOCATED NEAR THE NW CORNER OF MN SUPPORTED A BAND OF LIGHT
SHOWERS OVER N CNTRL MN. THE HEAVIER SHRA/TSRA REMAINED WELL TO THE
SOUTH FROM SE SD AND SW MN INTO NW IA ALONG THE 850 MB FRONT. AT THE
SFC...A WEAK TROUGH AHEAD OF THE MID LEVEL SHRTWV EXTENDED FROM NEAR
CYQT NRN MN. IR LOOP SHOWED MAINLY CLEAR SKIES OVER UPPER MI WITH
MID CLOUDS APPROACHING FROM NE MN.
TODAY...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE TIMING OF
THE SHRTWV ACROSS THE AREA BRINGING THIS FEATURE INTO CNTRL UPPER MI
AROUND 18Z AND QUICKLY TO LAKE HURON BY 00Z. THE COMBINATION OF THE
WEAK 700-300 MB QVECTOR CONV WITH THE SHRTWV AND LOW LEVEL CONV
ALONG THE TROUGH AND LAKE BREEZE BOUNDARIES SHOULD BE ENOUGH TO
SUPPORT AT LEAST SUPPORT ISOLD/SCT PCPN. MLCAPE VALUES TO AROUND 400
J/KG...PER NAM...WILL BE MARGINAL FOR TSRA BUT WITH THE ARRIVAL OF
THE SHRTWV DURING PEAK HEATING ISOLD TSRA WILL ALSO BE POSSIBLE.
TONIGHT...ANY SHRA/TSRA THAT DEVELOP DURING THE AFTERNOON WILL
DIMINISH WITH THE LOSS OF DAYTIME HEATING AND THE DEPARTURE OF THE
SHRTWV. A SLIGHT CHANCE FOR SHOWERS WAS MENTIONED AS ANOTHER WEAK
SHRTWV AND SFC MOVES THROUGH UPPER MI. EVEN THOUGH MOISTURE IS
LIMITED...SUCH WEAK DISTURBANCES IN THE BROAD CYCLONIC FLOW PATTERN
HAVE OFTEN MANAGED TO SUPPORT ISOLATED LIGHT SHOWERS.
HOWEVER...CONFIDENCE IN TIMING/POSITION OF ANY PCPN IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 316 AM EDT SUN AUG 11 2013
A QUIET WEEK IS IN THE MAKING FOR UPPER MICHIGAN AS HIGH PRESSURE
ANCHORS ITSELF OVER THE WESTERN GREAT LAKES. MOSTLY CLEAR SKIES
SHOULD BE THE RULE...THOUGH A SERIES OF WEAK SHORTWAVES COULD BE A
BIT PESKY WITH CLOUDS AROUND MID-WEEK. TEMPERATURES WILL SLOWLY WARM
TO NEAR NORMAL...WITH SEVERAL CHILLY NIGHTS
EXPECTED...ESPECIALLY TUESDAY NIGHT.
MONDAY AND MONDAY NIGHT...THE MAIN AXIS OF AN EASTERN CANADIAN
TROUGH WILL BE APPROACHING THE AREA AT THE START OF THE PERIOD.
MODEL GUIDANCE HAS STRUGGLED WITH MAINTAINING A STEADY APPROACH TO
THE STRUCTURE OF THIS TROUGH AXIS. THERE ARE SEVERAL DISTINCT AXES
EMBEDDED IN THE MAIN TROUGH...AND EACH SHOULD SWING THROUGH THE CWA
IN ABOUT 12 HOUR INTERVALS STARTING MONDAY MORNING. THE MAIN PLAYER
IN THIS SERIES IS CURRENTLY MOVING SSW INTO FAR NORTHWEST HUDSON BAY
AROUND THE WESTERN PERIPHERY OF AN IMPRESSIVE VORT MAX OVER CENTRAL
HUDSON BAY. BOTH ARE CLEARLY APPARENT IN WATER VAPOR SAT...SO SEE NO
REASON TO QUESTION MODEL PERFORMANCE WITH TIMING. THE TROUGH SHOULD
BE OVER WESTERN LAKE SUPERIOR BY 18Z MONDAY...AND EASTERN UPPER MI
AT 00Z TUESDAY. MID-LEVEL SUPPORT WILL BE PRESENT WITH MODEST H5
Q-VECTOR CONVERGENCE AND H7 FRONTOGENESIS. A SUBSIDENCE INVERSION
AROUND 600MB BEHIND SUNDAYS SYSTEM AND DRIER AIR BEHIND THE SFC
FRONT WILL LIMIT PCPN COVERAGE. LAKE BREEZE CONVERGENCE WILL ASSIST
PCPN DEVELOPMENT...BUT STABILIZING NW GRADIENT FLOW SHOULD CONFINE
BEST COVERAGE TO THE SOUTH-CENTRAL AND ALONG LAKE MI. THUNDER
POTENTIAL WILL BE MINIMAL WITH MUCAPE STRUGGLING TO REACH 500 J/KG
NORTH OF GRB. MOST OF THIS CAPE WILL BE BELOW THE 0C LEVEL...SO KEPT
THUNDER AT SLIGHT CHANCE OVER JUST THE SOUTH CENTRAL CWA.
MONDAY NIGHT AND TUESDAY...ANY PRECIP WILL DIMINISH WITH THE PASSAGE
OF AN ASSOCIATED SFC TROUGH AND LOSS OF DAYTIME HEATING MONDAY
EVENING. A SECOND MID-LEVEL WAVE CLOSER ASSOCIATED WITH THE MAIN
TROUGH AXIS WILL BE CROSSING THE CWA BY 12Z TUESDAY. THE NAM AND
ECMWF ARE A BIT SLOWER WITH THIS TROUGH AND ACTUALLY KICK OFF SOME
LIGHT SHOWER ACTIVITY ACROSS THE INTERIOR CENTRAL AND EAST TUESDAY
MORNING. WITH THE ATMOSPHERE QUITE DEPLETED OF MOISTURE AS NOTED BY
PWATS OF ONLY 0.7 INCHES...DO NOT EXPECT MUCH MORE THAN SOME
MID-LEVEL CLOUDINESS WITH MAYBE A FEW SPRINKLES. THIS DOES MAKE MIN
TEMPS FOR MONDAY NIGHT A LITTLE HARDER TO PIN DOWN. GIVEN THE
UNCERTAINTY IN MID-CLOUD COVER...OPTED NOT TO CHANGE MUCH AND LEAVE
TEMPS RANGING FROM THE MID 40S INTERIOR WEST TO THE LOW 50S ALONG
THE SHORE. QUITE A COOL TUESDAY WILL FOLLOW UNDER H8 TEMPS OF ONLY 4
TO 7C...COOLEST EAST. MIXING SHOULD REACH THE H8 LEVEL...SO TEMPS
ARE EXPECTED TO APPROACH 70F SOUTH CENTRAL. AN EXCELLENT MODIS SST
CAPTURE TODAY SHOWS LAKE TEMPS AROUND 50F IN THE NORTHERN OPEN
WATERS...AND MID 50S IN THE REMAINDER OF THE OPEN WATERS. SO EVEN
WITH A NORTH WIND...THE COASTAL AREAS SHOULD BE ABLE TO BREAK INTO
THE LOW 60S.
TUESDAY NIGHT THROUGH THURSDAY...SFC HIGH PRESSURE WILL SETTLE OVER
WESTERN UPPER MI TUESDAY NIGHT AS MID-LEVEL RIDGING ATTEMPTS TO
BUILD EASTWARD INTO THE UPPER MS VALLEY. LOW PWAT UNDER 0.5 INCHES
AND LIGHT WINDS WILL LEAD TO EXCELLENT RADIATIONAL COOLING.
CONTINUED USING A BLEND OF GUIDANCE THAT HAS PERFORMED WELL ON
SIMILAR NIGHTS OVER THE PAST FEW WEEKS. EXPECT 40S FOR ALL BUT THE
IMMEDIATE SHORE. SOME TYPICAL INTERIOR WEST COLD SPOTS COULD EVEN
SEE UPPER 30S.
A THIRD WAVE WILL SKIM THE NE CWA WEDNESDAY MORNING. LITTLE MOISTURE
AND MINIMAL LIFT WILL BRING ONLY SCATTERED MID-CLOUDS. ANOTHER WAVE
WILL FOLLOW THE SAME TRACK ON THURSDAY...BUT WILL SUCCUMB TO THE
SAME LIMITING FACTORS. CLOUDINESS SHOULD BE A LITTLE MORE AS LIMITED
MOISTURE RETURN BEGINS ON THE BACKSIDE THE SFC RIDGE.
FRIDAY AND SATURDAY...MODEL GUIDANCE IS SHOWING A TROUGH DROPPING SE
OVER NORTHERN ONTARIO LATE FRIDAY INTO SATURDAY. THOUGH GUIDANCE IS
SHOWING MORE CONSISTENCY...WILL CONTINUE CONSENSUS APPROACH TO
PRECIP CHANCES FOR NOW...WHICH SHOULD BE LIMITED TO SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 124 AM EDT SUN AUG 11 2013
EXCEPT FOR SOME SHALLOW GROUND FOG AT IWD EARLY THIS MRNG...EXPECT
VFR CONDITIONS THIS FCST PERIOD AT ALL THREE TAF SITES. A PASSING
DISTURBANCE MAY CAUSE SOME -SHRA THIS AFTN IN THE PRESENCE OF
DAYTIME HEATING AT SAW AND PERHAPS IWD...BUT CONFIDENCE IS TOO LO TO
INCLUDE MORE THAN VCSH IN THE TAFS ATTM. ANY -SHRA WL END BY SUNSET
WITH THE ONSET OF NOCTURNAL COOLING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EDT SUN AUG 11 2013
A SERIES OF WEAK TROUGHS WILL MOVE THROUGH LAKE SUPERIOR THROUGH
MONDAY. HOWEVER...WINDS ARE EXPECTED TO REMAIN LESS THAN 20 KNOTS.
HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT LAKES TUESDAY
THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS BILLINGS MT
319 AM MDT SUN AUG 11 2013
.SHORT TERM...VALID FOR TDY AND MON...
A BROAD 500-HPA RIDGE WILL KEEP A WARMING TREND GOING THE NEXT FEW
DAYS...BUT WEAK IMPULSES CUTTING THROUGH THE RIDGE WILL ALSO BRING
SOME CHANCES OF STORMS TO THE REGION AS WELL.
FIRST OF ALL...THE BOUNDARY LAYER IN SOUTHEASTERN MT IS VERY CLOSE
TO SATURATION AS OF 09 UTC...AND STRATUS IS BEGINNING TO FORM OVER
THE DAKOTAS AND AS FAR WEST AS BAKER. GIVEN WEAK EASTERLY GRADIENT
WINDS THROUGH THE MORNING...WE EXPECT STRATUS TO CONTINUE BUILDING
AND PROBABLY SET IN THROUGH AT LEAST LATE MORNING /A SCENARIO THAT
THE HRRR SUPPORTS/. WE WILL HAVE PATCHY FOG IN THE FORECAST ACROSS
SOUTHEASTERN MT THROUGH 15 UTC AS WELL. MEANWHILE...DRAINAGE WINDS
HAVE ACTUALLY TAKEN HOLD OVER SOUTH CENTRAL MT...WHICH HAS LOWERED
DEWPOINTS AND LIKELY NEGATED ANY FOG THREAT THIS MORNING IN PLACES
LIKE BILLINGS.
TODAY...WE HAVE REALIGNED AFTERNOON POPS TO FOCUS ON SOUTH CENTRAL
MT AND NORTH CENTRAL WY WHERE TERRAIN CIRCULATIONS WILL LIKELY AID
CONVECTIVE DEVELOPMENT...WHILE REMOVING THEM AND GOING WITHOUT ANY
MENTION OF STORM CHANCES IN MOST OF SOUTHEASTERN MT. THE CHOICE TO
GO WITH A DRY AFTERNOON FORECAST IN SOUTHEASTERN MT WAS BASED ON A
LACK OF DISCERNIBLE SHORT WAVE IMPULSES EITHER UPSTREAM IN MORNING
MOISTURE CHANNEL IMAGES OR IN AFTERNOON MODEL SIMULATIONS. NOT ONE
OF THE HIGH-RESOLUTION...CONVECTION-ALLOWING MODELS USED IN THE 00
UTC SPC SSEO DEVELOPED STORMS IN SOUTHEASTERN MT...WHICH CERTAINLY
HELPED BUILD OUR CONFIDENCE IN A DRY FORECAST. MLCAPE OF 1000 J/KG
WILL BE PRESENT DURING PEAK HEATING THOUGH...SO WE WILL KEEP WATCH
OF NEAR-TERM TRENDS IN CASE CHANCES NEED TO BE ADDED BACK IN LATER
ON. MEANWHILE...OVER SOUTH CENTRAL MT AND NORTH CENTRAL WY...AFTER
SEEING HOW EASILY CONVECTION FORMED SAT IN THIS SYNOPTIC SITUATION
OUR CONFIDENCE IN STORM DEVELOPMENT HAS INCREASED. THE MODELS FROM
00 UTC ADD SUPPORT FOR THIS. GUSTY WINDS OR EVEN A MARGINAL SEVERE
STORM IS POSSIBLE /SIMILAR TO SAT/. MOREOVER...THE 21 UTC SREF HAS
NOTABLE PROBABILITIES FOR DRY THUNDERSTORMS...WHICH IS A VERY REAL
POSSIBILITY WHERE FORECAST SOUNDINGS HAVE PRECIPITABLE WATERS LESS
THAN ABOUT 0.80 INCHES /WEST OF BILLINGS TOWARD LIVINGSTON/. BASED
ON MID- AND UPPER-LEVEL WINDS...STORM MOTIONS COULD BE SLOW ENOUGH
TO ELEVATE WETTING RAIN CHANCES A BIT MORE THAN THEY COULD BE IN A
SITUATION LIKE THIS...SO A LARGE-SCALE /RED FLAG-WORTHY/ LIGHTNING
EVENT IS NOT EXPECTED AT THIS TIME.
TONIGHT...THE 00 UTC SPC SSEO AS WELL AS 500-HPA VORTICITY MAXIMUM
FIELDS FROM THE 00 UTC GFS /AND TO AN EXTENT THE ECMWF/ SUPPORT 30
TO 40 PERCENT STORM CHANCES THIS EVENING FROM HARLOWTON TOWARD BIG
TIMBER AND EAST TO BILLINGS. GUSTY WINDS...MARGINAL SEVERE RISK...
AND SOME DRY LIGHTNING POTENTIAL WILL CONTINUE WITH STORMS THROUGH
THE EVENING AS WELL. LOW POPS ARE SUPPORTED OVER THE WHOLE AREA AS
A WEAK 500-HPA SHORT WAVE MAY MOVE INTO SOUTHEASTERN MT OVERNIGHT.
MON...THE LARGE-SCALE PATTERN WILL REMAIN SIMILAR...BUT THERE HAVE
BEEN SOME INDICATIONS FOR BETTER FORCING NEAR A STATIONARY FRONTAL
BOUNDARY IN SOUTHEASTERN MT DURING THE AFTERNOON AND EVENING. THAT
COULD GENERATE ANOTHER MORE NOTABLE SEVERE RISK GIVEN 0-6-KM SHEAR
VECTORS OF 30 KT OR MORE. WE NEED TO HAVE AT LEAST LOW POPS ACROSS
THE REST OF THE AREA AGAIN TOO. SCHULTZ
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
NO SIGNIFICANT CHANGES WERE MAE IN THE EXTENDED FORECAST PERIODS
FOR THIS PACKAGE. A RIDGE OF HIGH PRESSURE WILL DOMINATE THE
EXTENDED TIME FRAME WITH ACTIVE CONVECTIVE WEATHER THROUGH ABOUT
MIDWEEK...WINDING DOWN TO A DRIER AND WARMER REGIME FOR THE LATTER
PART OF THE WORK WEEK. LONG RANGE PROGGS DO INDICATE A SIGNIFICANT
WEATHER SYSTEM CRASHING THE RIDGE NEXT SATURDAY/SATURDAY NIGHT.
THIS WILL NEED TO BE MONITORED FOR FIRE WEATHER CONCERNS. BT
&&
.AVIATION...
A FEW LIGHT SHOWERS OR SPRINKLES WILL LINGER ACROSS THE FORECAST
AREA EARLY THIS MORNING...MAINLY ALONG AND NORTH OF A KLVM TO KBIL
AND KMLS LINE. AREAS OF FOG AND LOW CLOUDS ARE EXPECTED TO DEVELOP
BY SUNRISE AND LINGER THROUGH ABOUT 16Z FROM KMLS TO KBHK AND
SOUTHWARD. SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP ACROSS THE
AREA LATE THIS AFTERNOON AND INTO THE EVENING. LOCAL IFR TO MVFR
CAN BE EXPECTED WITHIN STRONGER THUNDERSTORMS. BT
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 088 062/088 059/086 060/087 060/091 062/093 062/091
2/T 32/T 22/T 22/T 20/U 00/U 01/U
LVM 090 054/089 052/088 052/088 050/091 051/095 051/090
3/T 32/T 22/T 22/T 21/U 10/U 01/U
HDN 089 060/091 058/089 058/088 059/092 059/095 059/093
2/T 22/T 32/T 22/T 20/U 00/U 00/U
MLS 087 063/088 061/087 061/087 061/091 063/094 064/093
1/B 23/T 32/T 23/T 31/U 00/U 01/U
4BQ 087 059/088 058/086 058/087 058/090 059/093 059/093
1/B 23/T 32/T 33/T 30/U 00/U 00/U
BHK 079 058/082 056/080 057/082 057/087 058/089 059/089
1/B 23/T 33/T 33/T 32/T 00/U 01/U
SHR 089 056/088 055/087 056/087 054/089 055/092 055/092
2/T 23/T 32/T 22/T 21/U 10/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
246 AM CDT SUN AUG 11 2013
.DISCUSSION...
PRECIPITATION CHANCES THROUGH MONDAY NIGHT PRIMARY FORECAST FOCUS
AS A WEAK FRONT SAGS ACROSS THE FA LATE TODAY INTO MONDAY.
EARLY MORNING SATELLITE/RADAR SHOWED A VORT MAX/TROUGH MOVG SE
ACROSS NWRN MN WITH SEVERAL CONVECTIVE CLUSTERS TO THE SW ON NOSE
OF LOW LEVEL JET/WARM ADVECTION OVR SD INTO NW IA. ALTHOUGH
VARIOUS SHORT TERM MODELS LIKE HOP WRF/RAP KEPT PRECIP MOSTLY NE
OF FA THIS AM ...4KM WRF AND HRRR DID TRY TO DEVELOP SOME OVER NRN
ZONES THIS MORNING. SO SOME SMALL POPS WILL BE MAINTAINED WITH
LAST MINUTE ADJUSTMENTS POSSIBLE BASED ON TRENDS BEFORE ISSUANCE.
OTHERWISE WITH BOUNDARY FORECAST TO SLOWLY SAG INTO NRN ZONES THIS
AFTN...HEATING SHOULD HELP REGENERATE CONVECTION LATER THIS
AFTERNOON...ALTHOUGH 4KM WHICH DEVELOPED IT MOSTLY S OF HIGHWAY 30
APPEARED TOO FAR S. COVERAGE THIS AFTERNOON AND EVOLUTION TONIGHT
IN DOUBT AS H5-H7 QG FORCING WAS NEGLIGIBLE WITH DIFFERENTIAL
HEATING ACROSS BOUNDARY THIS AFTN THEN SYSTEM MOTION FOR INFLOW
WOULD BE PRIMARY DRIVERS AS LOW LEVEL JET WEAKENS FAIRLY
SUBSTANTIALLY THROUGH TONIGHT. THUS KEPT POPS IN CHC CATEGORY FOR
NOW FOR LATE AFTN THROUGH EARLY TONIGHT. WITH THIS LACK OF LOW
LEVEL JET TONIGHT CONFIDENCE NOT VERY HIGH ON HOW MUCH COVERAGE
WILL EXIST AFTER 06Z OVER FA SO GENERALLY TRENDED POPS DOWN AFTER
THAT TIME. WITH MODEL AGREEMENT IN H85 THERMAL RIDGE POKING UP
TOWARD WCNTRL ZONES THIS AFTN BOOSTED HIGHS A BIT...WHICH WERE
STILL BELOW WARMER NAM WHICH ONE OF THESE DAYS MAY ACTUALLY TURN
OUT BETTER IF SWRLY SFC WINDS CAN BE MAINTAINED LONG ENOUGH.
IF CONVECTION TONIGHT PUSHES EFFECTIVE BOUNDARY SOUTH OF FA BY
MONDAY AFTN FURTHER CONVECTIVE DEVELOPMENT COULD BE LIMITED OVER
OUR AREA AND TRENDS WILL NEED MONITORING. HOWEVER...FOR NOW LEFT
IN CHC POPS S WITH SLIGHTS N THROUGH NORFOLK OR SO AS BOUNDARY
PUSH WAS MODEST AT BEST. ALTHOUGH H85 TEMPS DON/T COOL SIGNIFICANTLY
YET ON MONDAY...TEMPERATURES SHOULD BE SOMEWHAT COOLER MOST
AREAS...ESPECIALLY IF DEBRIS CLOUDS CAN BE MAINTAINED. SOME POPS
WERE KEPT THEN MONDAY NIGHT SW 2/3RDS OR SO IN CASE ANY UPSTREAM
CONVECTION WOULD HOLD TOGETHER...ALTHOUGH MUST SAY NOT REALLY SOLD
ON THAT IDEA.
IN FACT...EVEN THOUGH SOME SMALL POPS WERE ALSO MAINTAINED TO INTO
MIDWEEK BEFORE SPREADING E TOWARD FRIDAY...APPEARS BULK OF ANY
ACTIVITY COULD REMAIN TO OUR WEST THROUGH LATE WEEK...ESPECIALLY
PER 00Z ECMWF. THAT MODEL HAS REMAINED FAIRLY CONSISTENT IN THAT
REGARD. PLEASANT TEMPERATURES LOOK IN STORE FOR FORECAST AREA
MUCH OF NEXT WEEK BEFORE MODERATING LATE AS NORTHWESTERLY FLOW
SENDS CANADIAN HIGH PRESSURE DOWN MISSISSIPPI VALLEY. THIS HAS
BEEN ONE OF OUR SAVING GRACES THIS SUMMER AS SIGNIFICANTS RAINS
HAVE BEEN SPOTTY AND MANY AREAS ARE RUNNING MODERATE PRECIP
DEFICITS SINCE JUNE.
CHERMOK
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK AND KOFK.
VFR CONDITIONS PREVAIL THROUGH THE PERIOD WITH SOUTH TO SOUTHEAST
WINDS LESS THAN 10 KNOTS...THEN BECOMING SOUTHWEST BY 15 TO 18Z.
THUNDERSTORM CHANCES RETURN SUNDAY BY 20Z-02Z AT KOFK AS A COLD
FRONT APPROACHES THE REGION. THUNDERSTORMS COULD AFFECT KOMA
00-05Z AND KLNK 02-06Z.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
330 AM MDT SUN AUG 11 2013
.DISCUSSION...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
&&
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.AVIATION...
06Z TAF CYCLE
WIDESPREAD TSRA ACROSS MUCH OF THE AREA ALONG AND SOUTH OF I40 IS
MERGING INTO A LARGE SHIELD OF STRATIFORM RAINFALL SURROUNDING THE
ABQ METRO AREA. ANOTHER LARGE RAIN SHIELD WITH EMBEDDED THUNDER IS
SLIDING NORTHEAST OUT OF SOUTHERN NM WHERE VERY RICH MOISTURE IS
INTERACTING WITH AN UPPER LEVEL WAVE. CONFIDENCE HIGH ON RAINFALL
FOR AREAS ALONG AND SOUTH OF I-40 FOR REST OF TONIGHT...WITH THE
LOWEST CIGS AROUND KROW. MODEL SOUNDINGS INDICATE IFR CONDITIONS
BY MORNING OVER THIS REGION. THICK CLOUD COVER WILL LINGER OVER
THE REGION THROUGH MID MORNING WITH EVEN SOME SHOWERS CONTINUING
OVER THE EASTERN PLAINS. STORMS SHOULD BE LATE TO FIRE UP ACROSS
THE REGION SUNDAY AS HEATING WILL BE HARD TO COME BY UNTIL AFT 21Z.
GUYER
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 85 59 88 61 / 30 20 20 10
DULCE........................... 79 50 81 51 / 30 30 30 20
CUBA............................ 80 51 80 53 / 40 30 30 20
GALLUP.......................... 81 52 82 58 / 40 30 30 20
EL MORRO........................ 77 52 78 53 / 50 30 40 20
GRANTS.......................... 78 52 81 57 / 40 40 40 20
QUEMADO......................... 78 51 81 55 / 50 40 40 20
GLENWOOD........................ 83 58 87 61 / 40 40 20 20
CHAMA........................... 74 46 75 47 / 40 30 40 30
LOS ALAMOS...................... 78 55 81 56 / 40 30 30 20
PECOS........................... 77 54 80 55 / 40 30 30 20
CERRO/QUESTA.................... 78 47 77 49 / 30 30 40 30
RED RIVER....................... 69 45 67 45 / 50 30 50 30
ANGEL FIRE...................... 73 46 75 46 / 40 30 50 30
TAOS............................ 79 49 81 51 / 30 20 30 20
MORA............................ 76 51 76 51 / 40 30 40 30
ESPANOLA........................ 83 55 86 59 / 30 30 20 20
SANTA FE........................ 79 53 82 59 / 30 30 30 20
SANTA FE AIRPORT................ 82 56 84 59 / 30 20 20 20
ALBUQUERQUE FOOTHILLS........... 82 60 86 61 / 40 30 30 20
ALBUQUERQUE HEIGHTS............. 83 63 86 67 / 30 30 20 20
ALBUQUERQUE VALLEY.............. 85 60 89 65 / 30 30 20 20
ALBUQUERQUE WEST MESA........... 84 62 87 66 / 30 30 20 20
LOS LUNAS....................... 85 61 89 65 / 30 30 20 20
RIO RANCHO...................... 85 62 87 66 / 30 30 20 20
SOCORRO......................... 86 62 87 65 / 40 40 30 20
SANDIA PARK/CEDAR CREST......... 80 58 84 55 / 40 30 30 20
TIJERAS......................... 82 58 85 59 / 30 30 30 20
MORIARTY/ESTANCIA............... 81 55 83 58 / 40 30 30 20
CLINES CORNERS.................. 78 55 81 59 / 40 30 40 20
GRAN QUIVIRA.................... 79 56 81 60 / 40 40 30 20
CARRIZOZO....................... 82 60 83 62 / 40 30 20 20
RUIDOSO......................... 74 57 75 56 / 60 40 40 20
CAPULIN......................... 80 51 82 55 / 50 20 30 30
RATON........................... 82 53 83 55 / 40 20 30 30
SPRINGER........................ 81 53 86 57 / 40 20 30 30
LAS VEGAS....................... 78 53 81 56 / 40 30 30 20
CLAYTON......................... 88 61 89 63 / 30 20 30 30
ROY............................. 86 58 85 62 / 40 20 30 30
CONCHAS......................... 87 63 92 68 / 30 20 20 20
SANTA ROSA...................... 87 62 90 64 / 30 20 20 20
TUCUMCARI....................... 89 65 92 68 / 30 20 20 20
CLOVIS.......................... 87 64 89 66 / 40 20 20 10
PORTALES........................ 86 66 90 68 / 30 20 20 10
FORT SUMNER..................... 87 65 91 67 / 40 20 20 10
ROSWELL......................... 89 67 92 70 / 40 20 20 10
PICACHO......................... 83 61 86 64 / 50 30 20 20
ELK............................. 77 59 81 60 / 60 40 20 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
132 AM CDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 132 AM CDT SUN AUG 11 2013
SURFACE HIGH PRESSURE BUILDING SOUTH INTO NORTHERN NORTH DAKOTA
LATE TONIGHT...ADVECTING DRIER AIR SOUTH INTO THE REGION. THIS HAS
PRETTY MUCH ENDED ALL PRECIPITATION OVER THE CWA WITH THE
EXCEPTION OF A FEW LINGERING SHOWERS OVER MY SOUTHEAST.
MAIN CONCERN SHIFTS TO FOG DEVELOPMENT EARLY THIS MORNING ACROSS
THE NORTH AND EVENTUALLY SOUTHWARD AS SKIES TREND CLEAR. CROSBY
HAS REPORTED ZERO...WITH DEWPOINT DEPRESSIONS ELSEWHERE NEARING
OR AT ZERO. A DENSE FOG ADVISORY IS NOT OUT OF THE QUESTION BUT
WILL HOLD OFF FOR NOW WITH ONLY A FEW OBS COMING IN AT LESS THAN
ONE MILE.
UPDATE ISSUED AT 1015 PM CDT SAT AUG 10 2013
STRONG THUNDERSTORMS HAVE EXITED SOUTHWESTERN NORTH DAKOTA.
AN AREA OF SHOWERS WITH ISOLATED THUNDERSTORMS WILL CONTINUE TO
MOVE SOUTH ACROSS SOUTHWESTERN AND SOUTH CENTRAL NORTH DAKOTA
THROUGH THE OVERNIGHT HOURS. THIS SHOULD PRODUCE AN ADDITIONAL ONE
TENTH TO ONE QUARTER INCH OF PRECIPITATION OVER THE AFFECTED AREAS.
THE ONLY UPDATE TO THE FORECAST WAS TO REMOVE FIRST PERIOD POPS
FROM THE EASTERN ZONES AS DRIER AIR FILTERS IN FROM THE NORTH. THE
REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED GRIDDED
AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 715 PM CDT SAT AUG 10 2013
NUMEROUS THUNDERSTORMS WEST OF THE MISSOURI RIVER HAVE LOST
THEIR SEVERE CHARACTERISTICS WITHIN THE PAST HOUR WITH THE LOSS OF
DAYTIME HEATING. THUNDERSTORMS COULD BE STRONG AT TIMES DURING THE
NEXT HOUR OR SO. HOWEVER...A CONTINUED DOWNWARD TREND IN INTENSITY
IS EXPECTED TO CONTINUE WITH DECREASING CAPE.
THE 22Z HRRR PROGS THIS AREA OF CONVECTION TO CONTINUE TO PUSH
SOUTH ACROSS SOUTHWESTERN AND SOUTH CENTRAL NORTH DAKOTA THIS
EVENING. IT SHOULD CONTINUE WEAKEN AND MOVE OUT OF THE BISMARCK
CWA BY 09Z. UPDATED HOURLY POPS BASED ON THE LATEST RUN OF THE HRRR.
FURTHERMORE...HEAVY RAINFALL REPORTS OF ONE TO THREE INCHES IN SPOTS
WILL ADD TO RESIDUAL LOW LEVEL MOISTURE OVER WESTERN NORTH DAKOTA.
THE LATEST SHORT RANGE MODEL GUIDANCE PROGS THE CENTER OF A
SURFACE ANTICYCLONE TO SETTLE OVER NORTHWESTERN NORTH DAKOTA BY
EARLY SUNDAY MORNING. THE COMBINATION OF LIGHT WINDS AND RESIDUAL
LOW-LEVEL MOISTURE SHOULD ALLOW FOR AREAS OF FOG TO DEVELOP OVER
NORTHWESTERN NORTH DAKOTA...WITH PATCHY FOG POSSIBLE OVER
SOUTHWESTERN NORTH DAKOTA. UPDATED THE FORECAST TO REFLECT THIS
LINE OF REASONING.
THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
THE MAIN FORECAST CONCERN IN THE SHORT TERM PERIOD IS CONVECTIVE
TRENDS AND MARGINAL SEVERE POTENTIAL THROUGH TONIGHT. LATEST HI-
RES WRF/HRRR MODEL RUNS POINT TO POTENTIAL FOR STRONG STORMS
CONTINUING TO SPREAD INTO THE WEST THIS AFTERNOON/EVENING...SUPPORTED
BY A DECENT SHORT WAVE TROUGH CURRENTLY IN SOUTHERN
SASKATCHEWAN...AND ANOTHER IMPULSE IN CENTRAL MONTANA. MUCAPES AOA
1000 J/KG AND MARGINAL DEEP LAYER SHEAR SUGGEST AN ISOLATED STORM
OR TWO CAPABLE OF QUARTER SIZE HAIL. INVERTED V BUFR SOUNDINGS
ALSO INDICATE SOME GUSTY WIND POTENTIAL WITH STORM DOWNDRAFTS. STORMS
IN FAR NORTHEAST MONTANA HAVE ALREADY PRODUCED SOME HAIL UP TO
PENNY SIZE IN ROOSEVELT COUNTY. ALSO THINKING THE SHORTWAVE WILL
SUSTAIN SHOWERS AND STORMS INTO CENTRAL AND SOUTHEAST COUNTIES
AFTER DARK. LOOKING AHEAD...ISOLATED STORMS WILL AGAIN BE POSSIBLE
SUNDAY AFTERNOON IN THE EXTREME SOUTHWEST WITH THE ARRIVAL OF
ANOTHER PIECE OF MID-LEVEL ENERGY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 225 PM CDT SAT AUG 10 2013
MAIN FORECAST CONCERNS ARE INTERMITTENT PRECIP CHANCES THROUGH
THE PERIOD. GFS/ECMWF/GEM/ENSEMBLES ARE ALL IN GOOD AGREEMENT WITH
OVERALL PATTERN THROUGH THE EXTENDED. UPPER LEVEL PATTERN WILL
CONSIST OF WESTERN N AMERICAN RIDGE IN PLACE WITH EASTERN N
AMERICAN TROUGH. THIS PLACES THE NORTHERN PLAINS IN NORTHWEST FLOW
WITH OCCASIONAL DISTURBANCES MOVING ACROSS THE REGION...SUPPORTING
INTERMITTENT CHANCES OF PRECIPITATION. BEST CHANCES FOR PRECIP
WILL BE ACROSS SOUTHWEST PORTION OF THE STATE...CLOSER TO BEST
INSTABILITY. 00Z ECMWF SHOWS A BETTER DEFINED SHORTWAVE IN
NORTHWEST FLOW ON THURSDAY. FOR NOW...WILL CONTINUE TO CARRY SMALL
POCKET OF CHANCE POPS ASSOCIATED WITH THIS FEATURE INTO CENTRAL
NORTH DAKOTA THURSDAY...BUT OTHERWISE ANY PRECIP CHANCES REMAIN
RELATIVELY LOW IN THE SLIGHT CHANCE CATEGORY.
WITH REGARD TO TEMPERATURES...MAX TEMPS EARLY IN THE PERIOD SHOULD
START OUT SLIGHTLY BELOW NORMAL. NORMAL HIGH FOR BIS IS 85 FOR THE
NEXT SEVERAL DAYS. AS RIDGE AXIS OVER THE WEST NUDGES EASTWARD
SLIGHTLY...WE SHOULD SEE TEMPS BACK TO THE LOW 80S BY MID WEEK.
SLIGHT DIFFERENCES IN MODEL SOLUTIONS BY NEXT SATURDAY BUT
GFS/ECMWF/ENSEMBLES SUPPORT RIDGE AXIS OVER OR JUST TO THE WEST OF
ND WHICH WOULD SUPPORT ABOVE NORMAL TEMPS. 12Z MOS GUIDANCE GIVES
BIS A HIGH OF 92 NEXT SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 132 AM CDT SUN AUG 11 2013
MAIN AVIATION CONCERN WILL BE POSSIBLE FOG/LOW STRATUS DEVELOPMENT
ACROSS THE NORTH AND JAMES RIVER VALLEY NOW THROUGH 15Z SUNDAY
MORNING. OTHERWISE EXPECT VFR THROUGH THE REMAINDER OF THE PERIOD.
MAY SEE AN ISOLATED THUNDERSTORM THIS AFTERNOON/EVENING AT KDIK.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
LONG TERM...JNS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
537 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN
DURING THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING
MUCH QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH
SHOT OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS
TEMPERATURES AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS
TO TURN SW LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND
APPROACHES. QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA
AND PLENTY OF SUN.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
AS WAS THE CASE YESTERDAY...SOME SHOWERS ON THE RADAR.
I WAS THINKING THAT ANY SHOWERS WOULD BE ALONG THE MD
LINE...NOT UP BY I-80. STILL EXPECT THESE TO BE AWAY FROM
OUR TAF SITES.
A LOT OF CLDS...SO TOOK FOG OUT OF THE 06Z PACKAGE...BUT
A LITTLE FOG HERE AND THERE...BEEN ADJUSTING THE FCST FOR
THIS.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
432 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN DURING
THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING MUCH
QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH SHOT
OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS TEMPERATURES
AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS TO TURN SW
LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND APPROACHES.
QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA AND PLENTY OF
SUN.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
SOME CLDS AROUND 3500 FEET JUST TO THE NORTH AND WEST OF
THE OFFICE...WILL PREVAIL THROUGH SUNRISE. NOT CLEAR WHY
THESE EXIST...BUT GIVEN THE CLDS...TOOK FOG OUT OF THE TAFS.
RADAR RETURNS MOVING FAST...NOT SEEING ANY MID LVL CLDS...
THUS HARD TO SEE WHY ANYTHING IS MOVING THIS FAST.
THERE COULD BE A BRIEF SPRINKLE ALONG THE MD BORDER LATER
TODAY AND SUNDAY NIGHT...BUT LIKELY TO BE SOUTH OF ANY OF
OUR TAF SITES.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
220 AM EDT SUN AUG 11 2013
.SYNOPSIS...
A WEAK WEATHER SYSTEM IS BRINGING VARIABLE CLOUD COVER TO THE
REGION OVERNIGHT TONIGHT. A FEW ISOLATED SHOWERS ARE POSSIBLE
ACROSS WESTERN PENNSYLVANIA. SUNDAY WILL FEATURE PARTLY TO MOSTLY
CLOUDY SKIES WITH JUST A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM
TO PORTIONS OF THE AREA. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
OVERVIEW...MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE IS IN VERY
GOOD AGREEMENT IN MAINTAINING A RELATIVELY AMPLIFIED PATTERN
THROUGH THE MIDDLE/LATE PART OF NEXT WEEK. THIS WILL BE GENERALLY
CHARACTERIZED BY FOUR CORNERS/ROCKIES UPPER RIDGING AND MEAN
TROUGHING OVER THE EASTERN THIRD OF THE CONUS. A POLAR FRONT WILL
PUSH SEWD FROM THE LOWER GRT LKS ACROSS THE MID-ATLANTIC/NORTHEAST
STATES ON TUESDAY. BEHIND THE FRONT...A LARGE DOME OF HIGH
PRESSURE BUILDING SEWD FROM THE SOUTH-CENTRAL CANADIAN PRAIRIES
WILL DOMINATE THE REGIONAL WEATHER PATTERN THROUGH THE END OF THE
PERIOD.
HIGHLIGHTS...AT LEAST MARGINAL/ISOLATED SEVERE TSTMS MAY BE
POSSIBLE ON DAY 4/TUE AS BROAD HEIGHT FALLS AND RELATIVELY COOL
TEMPERATURES/STRONG CYCLONIC WINDS ALOFT SPREAD ACROSS THE REGION
IN ASSOCIATION WITH THE AMPLIFYING UPPER TROUGH CROSSING THE GRT
LKS. DETAILS SUCH AS FRONTAL TIMING AND DEGREE OF DESTABILIZATION
ARE STILL IN QUESTION...HOWEVER A CATEGORICAL SLGT RISK OUTLOOK
SEEMS PROBABLE. ADDED 5-10 PCT TO POPS INCREASING TO LKLY IN MOST
AREAS...WHICH IS IN LINE WITH THE LATEST CONSENSUS MOS DATA.
A REFRESHINGLY COOL/DRY CANADIAN AIRMASS IS FCST TO FILTER INTO
THE AREA BEHIND THE FRONT. 10/12Z GEFS MEAN PWS STAY BELOW NORMAL
FROM TUE NGT THRU EARLY FRI...WHICH SUPPORTS A COOL AND DRY
MID/LATE WEEK PERIOD WITH TEMPERATURES AVERAGING BELOW NORMAL.
ALSO ANTICIPATE A FEW RELATIVELY COOL/CHILLY MORNINGS WITH UPPER
30S POSSIBLE A.M. THURSDAY OVER THE NRN TIER.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SOME CLDS AROUND 3500 FEET JUST TO THE NORTH AND WEST OF
THE OFFICE...WILL PREVAIL THROUGH SUNRISE. NOT CLEAR WHY
THESE EXIST...BUT GIVEN THE CLDS...TOOK FOG OUT OF THE TAFS.
RADAR RETURNS MOVING FAST...NOT SEEING ANY MID LVL CLDS...
THUS HARD TO SEE WHY ANYTHING IS MOVING THIS FAST.
THERE COULD BE A BRIEF SPRINKLE ALONG THE MD BORDER LATER
TODAY AND SUNDAY NIGHT...BUT LIKELY TO BE SOUTH OF ANY OF
OUR TAF SITES.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...STEINBUGL
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
156 AM EDT SUN AUG 11 2013
.SYNOPSIS...
A WEAK WEATHER SYSTEM IS BRINGING VARIABLE CLOUD COVER TO THE
REGION OVERNIGHT TONIGHT. A FEW ISOLATED SHOWERS ARE POSSIBLE
ACROSS WESTERN PENNSYLVANIA. SUNDAY WILL FEATURE PARTLY TO MOSTLY
CLOUDY SKIES WITH JUST A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM
TO PORTIONS OF THE AREA. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND TUESDAY
WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
OVERVIEW...MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE IS IN VERY
GOOD AGREEMENT IN MAINTAINING A RELATIVELY AMPLIFIED PATTERN
THROUGH THE MIDDLE/LATE PART OF NEXT WEEK. THIS WILL BE GENERALLY
CHARACTERIZED BY FOUR CORNERS/ROCKIES UPPER RIDGING AND MEAN
TROUGHING OVER THE EASTERN THIRD OF THE CONUS. A POLAR FRONT WILL
PUSH SEWD FROM THE LOWER GRT LKS ACROSS THE MID-ATLANTIC/NORTHEAST
STATES ON TUESDAY. BEHIND THE FRONT...A LARGE DOME OF HIGH
PRESSURE BUILDING SEWD FROM THE SOUTH-CENTRAL CANADIAN PRAIRIES
WILL DOMINATE THE REGIONAL WEATHER PATTERN THROUGH THE END OF THE
PERIOD.
HIGHLIGHTS...AT LEAST MARGINAL/ISOLATED SEVERE TSTMS MAY BE
POSSIBLE ON DAY 4/TUE AS BROAD HEIGHT FALLS AND RELATIVELY COOL
TEMPERATURES/STRONG CYCLONIC WINDS ALOFT SPREAD ACROSS THE REGION
IN ASSOCIATION WITH THE AMPLIFYING UPPER TROUGH CROSSING THE GRT
LKS. DETAILS SUCH AS FRONTAL TIMING AND DEGREE OF DESTABILIZATION
ARE STILL IN QUESTION...HOWEVER A CATEGORICAL SLGT RISK OUTLOOK
SEEMS PROBABLE. ADDED 5-10 PCT TO POPS INCREASING TO LKLY IN MOST
AREAS...WHICH IS IN LINE WITH THE LATEST CONSENSUS MOS DATA.
A REFRESHINGLY COOL/DRY CANADIAN AIRMASS IS FCST TO FILTER INTO
THE AREA BEHIND THE FRONT. 10/12Z GEFS MEAN PWS STAY BELOW NORMAL
FROM TUE NGT THRU EARLY FRI...WHICH SUPPORTS A COOL AND DRY
MID/LATE WEEK PERIOD WITH TEMPERATURES AVERAGING BELOW NORMAL.
ALSO ANTICIPATE A FEW RELATIVELY COOL/CHILLY MORNINGS WITH UPPER
30S POSSIBLE A.M. THURSDAY OVER THE NRN TIER.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
MAINLY JUST SCT-BKN CIRRUS STREAMING OVERHEAD TONIGHT IN STRONG
WESTERLY FLOW ALOFT. BUT A WEAK DEWPOINT BOUNDARY OVER NW PA/E OH
COMBINED WITH LIGHT NE FLOW AT LOWER LEVELS AND SLIGHT CONVERGENCE
IN THE 850MB FLOW HAS INITIATED AN AREA OF STRATOCU BASED AROUND
4000 FT. THESE CLOUDS WILL LIKELY SLIP INTO KBFD-KJST OVER NEXT
FEW HOURS AND MAY LINGER MUCH OF THE OVERNIGHT. BUT OVERALL...VFR
CONDITIONS EXPECTED TONIGHT WITH ONLY SOME PATCHY VALLEY FOG
FORMING FOR A COUPLE HOURS CLOSE TO SUNRISE.
ON SUNDAY...A WEAK WEATHER DISTURBANCE WILL BRING A CHANCE FOR A
SHOWER ALONG THE PA/MD BORDER NEAR KJST LATE IN THE DAY...BUT WILL
HAVE A HARD TIME PUSHING NORTH/EAST OF THAT. VFR CONDITIONS AND
LIGHT WINDS CONTINUE.
OUTLOOK...
SUN-MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
MON NIGHT-TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND SCT
TSTMS.
TUE NIGHT-THU...PRIMARILY VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...STEINBUGL
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
329 AM CDT SUN AUG 11 2013
DISCUSSION...
WEAK STATIONARY FRONTAL BOUNDARY IS POSITIONED JUST NW OF THE MID
STATE THIS MORNING. IT NOW APPEARS THAT THIS FEATURE WILL MOVE
LITTLE OVER THE NEXT 24-48 HRS. OTW..CURRENT RADAR SHOWING SOME SCT
CONVECTION ACROSS FAR NORTHERN PORTIONS OF THE MID STATE. WESTERLIES
ALOFT ARE STILL IN PLACE AS THE W-E UPPER RIDGE REMAIN SUPPRESSED TO
OUR SOUTH.
LATEST HRRR SUPPORTING LESS IN THE WAY OF CONVECTION TODAY AND
TONIGHT. THIS IS FURTHER ENFORCED BY DRIER MOISTURE DEPTH LEVELS AS
COMPARED TO PREVIOUS DAYS. STILL THOUGH...PLENTY OF HUMIDITY TO
WORK WITH AND CANNOT RULES OUT LOW POPS FOR TODAY AND TONIGHT IN THE
20-40 PERCENT RANGE.
AS WE GO THROUGH MONDAY AND TUESDAY...MID LEVEL TEMPS WILL BEGIN TO
COOL AS AN UPCOMING TROUGHING PATTERN BEGINS TO EMERGE. AS OUR WINDS
ALOFT BECOME MORE NORTHERLY...A STRONGER COLD FRONT WILL BEGIN TO
PUSH SOUTHWARD AND FURTHER INCREASE PRECIP CHANCES. LOOKS AS THOUGH
THE FROPA WILL OCCUR SOMETIME LATE WEDNESDAY AS IT APPEARS TO SLOW
DOWN A BIT. WILL GO AHEAD AND INCLUDE INCREASING POPS WITH TIME WITH
LIKELY VALUES BY TUESDAY. TEMPERATURES WILL RUN A DEGREE OR TWO
ABOVE NORMAL. MOS NUMBERS LOOK REASONABLE.
IN THE EXT FCST...SHOWER AND TSTM CHANCES WILL REMAIN RATHER HIGH ON
WEDNESDAY AS THE FRONT REMAINS IN CLOSE PROXIMITY. SOME DRIER AIR
WILL WORK IN THU-SAT BUT AFTERNOON ELEVATED CAPE VALUES WILL
RETURN BY THE WEEKEND. THEREFORE...LOW 20-30 POPS WILL RETURN BY
THE TAIL END OF THE EXTENDED.
OTW...STILL LOOKING AT A COOLING TREND FOR THE EXT WITH LOWS MID TO
UPPER 60S...HIGHS MID 80S...COOLER PLATEAU.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 89 72 89 71 / 30 30 40 50
CLARKSVILLE 88 68 89 68 / 30 30 40 50
CROSSVILLE 84 66 84 66 / 40 30 40 50
COLUMBIA 89 72 89 71 / 40 30 50 50
LAWRENCEBURG 89 70 88 70 / 40 30 50 50
WAVERLY 88 69 89 69 / 30 30 40 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
346 AM CDT SUN AUG 11 2013
.SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
&&
.MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
&&
.LONG-TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 40 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 40 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
PZ/83...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1141 PM CDT SAT AUG 10 2013
.UPDATE...
ISSUED AT 949 PM CDT SAT AUG 10 2013
CONTINUE TO MONITOR CONVECTIVE TRENDS FOR THE OVERNIGHT PERIOD AS
A SYSTEM MOVES INTO THE REGION. CURRENTLY...SHOWERS HAVE FIZZLED
ACROSS SOUTHERN MINNESOTA AS AN INITIAL MID LEVEL SHORTWAVE TROUGH
HAS WEAKENED AS IT HAS TRACKED EAST TOWARD THE MISSISSIPPI RIVER.
THE STRONGER LIFT IS STILL WELL BACK TO THE WEST ALONG TWO
SEPARATE FEATURES...A FRONTOGENETIC BAND IN SOUTHEAST SOUTH DAKOTA
AND A MID LEVEL SHORT WAVE TROUGH IN NORTH DAKOTA. THE PAST FEW
RUNS OF THE HRRR AND RAP HAVE BROUGHT SOME OF THE SCATTERED LIGHT
RAIN SHOWERS INTO THE REGION THROUGH THE NEXT 6 HOURS OR SO...BUT
DO NOT EXPECT MUCH IF ANYTHING OUT OF THESE. THE MAIN SHOW WILL
COME IN INITIALLY WITH THE BAND OF FRONTOGENESIS THAT HAS HELPED
CONVECTION DEVELOP IN SOUTHEAST SOUTH DAKOTA ALONG A SURFACE WARM
FRONT. THIS BAND IS GOING TO VERY SLOWLY DRIFT EAST OVERNIGHT AND
MAY NOT REACH THE REGION UNTIL LATER IN THE MORNING. THIS LEADS TO
SOME QUESTIONS ABOUT HOW MUCH WILL BUILD IN AHEAD OF IT AS LOW
LEVEL MOISTURE TRANSPORT DOES TRY TO INCREASE FROM THE SOUTHWEST.
BASED ON THIS...WILL HAVE TO BACK OFF ON THE PRECIPITATION CHANCES
A LITTLE OVERNIGHT BUT WILL KEEP THEM ON THE HIGHER SIDE TOMORROW
MORNING AND AFTERNOON.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 347 PM CDT SAT AUG 10 2013
MAIN FORECAST CONCERNS ARE ON SHOWERS AND THUNDERSTORMS LATE TONIGHT
THROUGH SUNDAY NIGHT.
LATEST WATER VAPOR IMAGERY SHOWED WEST/NORTHWEST FLOW ALOFT ACROSS
THE REGION. TWO MAIN SHORTWAVES TO FOCUS ON OVER THE NEXT 36
HOURS...A LEADING WAVE OVER EASTERN SOUTH DAKOTA AND
ANOTHER VIGOROUS SHORTWAVE OVER SOUTHERN SASKATCHEWAN DIGGING
SOUTHEAST INTO WESTERN NORTH DAKOTA. SHOWERS AND EMBEDDED
THUNDERSTORMS WERE OCCURRING OVER EASTERN AND NORTH CENTRAL SOUTH
DAKOTA. AN ADDITIONAL AREA OF SHOWERS AND STORMS WERE ERUPTING
OVER EXTREME NORTHWEST MONTANA AND NORTHWESTERN NORTH DAKOTA.
THE SHORTWAVE OVER EASTERN SOUTH DAKOTA WILL MAKE ITS WAY EAST INTO
THE FORECAST AREA LATE THIS EVENING. MEANWHILE...THE NORTHERN
SHORTWAVE WILL BE PUSHING SOUTHEAST INTO THE REGION AS A 250MB JET
STREAK INTENSIFIES AND SAGS SOUTH...PLACING THE RIGHT ENTRANCE REGION
OVER CENTRAL MINNESOTA/INTO CENTRAL WISCONSIN. A FRONTAL BOUNDARY
WILL ORIENT ITSELF RIGHT ALONG THE INTERSTATE 90 CORRIDOR LATE THIS
EVENING INTO THE OVERNIGHT HOURS AND PROVIDE THE FOCUS FOR SHOWER
AND THUNDERSTORMS DEVELOPMENT. THINKING A COMPLEX OF SHOWERS AND
STORMS SHOULD INTENSIFY OVER SOUTHEAST SOUTH DAKOTA/SOUTHWEST
MINNESOTA/NORTHWEST IOWA...THEN PUSH EAST INTO THE FORECAST AREA LATE
TONIGHT INTO EARLY SUNDAY MORNING. THERE IS A GENERAL INCREASE IN
MOISTURE TRANSPORT INTO THE FRONT OVERNIGHT INTO SATURDAY
MORNING AND A RATHER IMPRESSIVE INCREASE IN FRONTOGENESIS
ESPECIALLY IN THE NAM. WHILE THE NAM APPEARS TO BE CONTAMINATED BY
SOME CONVECTION...THINKING IT HAS THE RIGHT IDEA WITH AN INCREASE
IN FRONTOGENESIS IN THE 9 TO 15Z TIME FRAME. ADDITIONAL SHOWER AND
POSSIBLY SCATTERED THUNDERSTORM DEVELOPMENT IS LIKELY AHEAD OF THE
MAIN COMPLEX OF STORMS WORKING INTO THE AREA FROM THE WEST
TONIGHT. PLAN ON SHOWERS AND STORMS TO SPREAD INTO AREAS WEST OF
THE MISSISSIPPI RIVER AFTER MIDNIGHT THEN WORKING EAST INTO
CENTRAL AND SOUTHWEST WISCONSIN AROUND DAYBREAK SUNDAY MORNING.
SOME HEALTHY RAINFALL AMOUNTS IN STORE FOR LOCATIONS ALONG AND
SOUTH OF INTERSTATE 90...WHERE RAINFALL COULD TOTAL 1/2 INCH TO
NEARLY ONE INCH DEPENDING ON EXACTLY WHERE THE BAND SETS UP. THE
BAND OF SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL PERSIST OVER
THE AREA THROUGH THE MORNING HOURS AND INTO SUNDAY AFTERNOON THEN
SHOULD GRADUALLY START TO SHIFT SOUTHWARD. THE ABUNDANT CLOUD
COVER AND ONGOING SHOWERS AND STORMS WILL HELP LIMIT HOW MUCH
INSTABILITY BUILDS THROUGH THE DAY AND WILL ALSO ACT TO KEEP
TEMPERATURES ON THE COOL SIDE WITH HIGHS ONLY IN THE LOWER 70S. IN
FACT...LOCATIONS RIGHT UNDER THE BAND WILL STRUGGLE TO GET OUT OF
THE 60S. IF THERE HAPPENS TO BE A BREAK IN THE ACTIVITY FROM MID
SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON AND ENOUGH INSTABILITY
CAN BUILD ALONG THE FRONTAL BOUNDARY THERE IS AN OUTSIDE CHANCE OF
A STRONGER THUNDERSTORM OVER NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. THE OVERALL PROBABILITY OF THIS OCCURRING OVER THESE
AREA APPEARS LOW AT THIS TIME...BUT WILL HAVE TO KEEP A CLOSE EYE
ON CLOUD/PRECIPITATION TRENDS. FORECAST MODELS ATTEMPT TO INCREASE
THE INSTABILITY RIGHT ALONG THE BOUNDARY SUNDAY AFTERNOON OVER
NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN WITH MLCAPE VALUES
CLIMBING TO AROUND 1100 J/KG. 0-6KM BULK SHEAR VALUES HOVERING
AROUND 40 KTS WOULD BE SUFFICIENT FOR A SEVERE STORM OR TWO. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS. ALSO...WILL
HAVE TO KEEP A CLOSE EYE ON ANY STORMS THAT WOULD DEVELOP RIGHT
ALONG THE BOUNDARY WHERE SHEAR PROFILES COULD POSSIBLY SUPPORT A
TORNADO. ALL OF THIS IS CONDITIONAL ON AFTERNOON DESTABILIZATION.
ONGOING SHOWERS AND STORMS WILL GRADUALLY TAPER OFF SUNDAY EVENING
INTO LATE SUNDAY NIGHT AS THE BOUNDARY SLIPS SOUTH AND THE JET
STREAK WEAKENS SLIGHTLY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 347 PM CDT SAT AUG 10 2013
SHOWERS AND STORMS TAPER OFF SUNDAY NIGHT THEN ANOTHER TROUGH DIVES
SOUTH OUT OF CANADA AND INTO THE UPPER MISSISSIPPI RIVER VALLEY
MONDAY AFTERNOON INTO TUESDAY. THIS FEATURE MAY GENERATE A FEW
SHOWERS AND ISOLATED STORMS AS IT MOVES THROUGH...PARTICULARLY OVER
NORTH CENTRAL WISCONSIN. CANADIAN HIGH PRESSURE THEN BUILDS INTO THE
AREA TUESDAY THROUGH THURSDAY WITH DRY AND QUIET CONDITIONS
EXPECTED. WILL HAVE TO KEEP A CLOSE EYE ON THE POTENTIAL FOR VALLEY
FOG WITH THE HIGH OVERHEAD AND LIGHT WINDS. PLAN ON SEASONABLY COOL
TEMPERATURES THROUGH THE THE WEEK WITH HIGHS IN THE MID TO UPPER
70S. RAIN CHANCES RETURN THURSDAY NIGHT THROUGH FRIDAY NIGHT AS
WEAK SHORTWAVES MOVE THROUGH THE REGION. HOWEVER...LATEST MODEL
GUIDANCE HINTS AT THIS TIME FRAME POSSIBLY ENDING UP DRY. IF MODEL
TRENDS CONTINUE PRECIPITATION CHANCES MAY NOT BE NEEDED DURING
THIS TIME FRAME WITH THE SURFACE HIGH HOLDING STRONG FROM THE
MIDDLE OF NEXT WEEK ALL THE WAY INTO NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1141 PM CDT SAT AUG 10 2013
SHOWERS AND A FEW THUNDERSTORMS ARE TRACKING EAST ACROSS SOUTHERN
MINNESOTA AND WILL BECOME MORE WIDESPREAD THROUGH SUNDAY MORNING.
SOME MVFR CONDITIONS ARE POSSIBLE AS THE MORNING PROGRESSES AND
THE RAIN PERSISTS. WHILE SOME SCATTERED LIGHT RAIN SHOWERS ARE
DEVELOPING NEAR RST...THE MAIN CLUSTER OF SHOWERS AND
THUNDERSTORMS WILL MOVE INTO RST AROUND 8Z AND LSE AROUND 10Z.
THIS RAIN COULD HANG OUT ACROSS THE REGION THROUGH MUCH OF THE
MORNING AND PERHAPS INTO THE EARLY AFTERNOON AS THIS SYSTEM MOVES
THROUGH. IF SOME THUNDERSTORMS DEVELOP...CAN NOT RULE OUT SOME IFR
CONDITIONS DEVELOPING FOR A BRIEF PERIOD. OTHERWISE...EXPECT THAT
CONDITIONS WILL IMPROVE INTO SUNDAY EVENING AS THE SYSTEM DROPS TO
THE SOUTHEAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS BOISE ID
906 AM MDT SUN AUG 11 2013
.DISCUSSION...MADE SOME MINOR UPDATES TO BOOST POPS IN NORTHERN
PORTION OF FORECAST AREA INCLUDING BAKER COUNTY OREGON...THE
WEST CENTRAL MOUNTAINS AND NORTHERN BOISE MOUNTAINS IN IDAHO.
THESE AREAS NOW LOOK LIKE A GOOD BET TO SEE SCATTERED
THUNDERSTORMS THIS AFTERNOON AND EVENING. THIS THINKING IS
SUPPORTED BY OBSERVATIONS...MODEL DATA AND SATELLITE IMAGERY. THE
12Z SOUNDING AT BOISE IS MORE MOIST TODAY AND PROJECTED TO BE MORE
UNSTABLE IN THE AFTERNOON THAN YESTERDAY. EARLY MORNING VISIBLE
SATELLITE IMAGERY ALREADY SHOWS LOTS OF CUMULUS CLOUDS IN EASTERN
OREGON AND IN IDAHO. THE 12Z RUNS OF THE NAM AND HRRR MODELS SHOW
SCATTERED CONVECTION BREAKING OUT AROUND 21Z. THE MAIN THREAT WITH
THESE THUNDERSTORMS WILL BE LIGHTNING AND GUSTY WINDS WHICH COULD
LEAD TO ADDITIONAL FIRE STARTS IN THE FORESTS. DRIER AIR IN NEVADA
SHOULD MOVE INTO SOUTHERN OREGON AND SOUTHERN IDAHO TODAY FOR
MOSTLY SUNNY AND HOT WEATHER THERE. SOUTHERLY WINDS SHOULD
CONTINUE TO BLOW WILD FIRE SMOKE TOWARDS THE NORTH TODAY...KEEPING
THE TREASURE AND MAGIC VALLEYS RELATIVELY SMOKE FREE WHILE
BRINGING DENSE SMOKE TO MCCALL...DONNELLY...IDAHO CITY...CASCADE AND
OTHER AREAS IN THE WEST CENTRAL MOUNTAINS OF IDAHO.
&&
AVIATION...WIDESPREAD SMOKE LAYERS ALOFT THROUGH MONDAY...CAUSING
AREAS OF TERRAIN OBSCURATION IN THE BOISE AND W CENTRAL IDAHO
MOUNTAINS...WITH MVFR AND LOCAL IFR CONDITIONS IN THE VALLEYS UNTIL
18Z AND AFTER 06Z MONDAY. AFTER 18Z...ISOLATED THUNDERSTORMS
...EXCEPT SCATTERED THUNDERSTORMS OVER N HARNEY AND W BAKER
COUNTIES AS WELL AS N OF A LINE FROM ONTARIO OREGON TO IDAHO CITY
IDAHO. SURFACE WINDS...LIGHT EXCEPT NEAR THUNDERSTORMS. WINDS
ALOFT...SOUTH AVERAGING 12 KTS AT 10K FEET MSL.
&&
.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH MONDAY...UPPER LOW CENTERED ALONG THE
OREGON COAST WILL DRIFT SLOWLY NORTHWARD REACHING THE WASHINGTON
COAST TONIGHT AND MONDAY. THERE IS SOME MOISTURE AVAILABLE ACROSS SE
OREGON AND SW IDAHO FOR CONVECTION. PWAT/S ARE AROUND 0.75 INCHES
THROUGH MONDAY...WHICH IS SLIGHTLY ABOVE NORMAL. THERE IS ALSO SOME
WEAK UPPER LEVEL SUPPORT FOR CONVECTION DUE TO OUR PROXIMITY TO THE
UPPER LOW. DAYTIME HEATING WILL INITIATE CONVECTION THIS
AFTERNOON...WITH ISOLATED SHOWERS AND THUNDERSTORMS DEVELOPING
ACROSS SE OREGON AND THE HIGHER TERRAIN OF SW IDAHO. THUNDERSTORMS
WILL BE SCATTERED IN BAKER COUNTY. SOUTHERLY FLOW THIS AFTERNOON
WILL BRING DENSE SMOKE FROM FIRES IN ELMORE AND CAMAS COUNTY
NORTHWARD INTO THE BOISE/WEST CENTRAL MTNS. THE SMOKE MAY BE DENSE
ENOUGH TO INHIBIT HEATING THUS LIMITING CONVECTION. PWAT/S OF AROUND
0.75 INCHES AND THE OVERALL PATTERN OF SW FLOW ALOFT WILL CONTINUE
THROUGH MONDAY SO EXPECT A REPEAT OF AFTERNOON CONVECTION...WITH
SLIGHT CHANCE OF SHOWERS AND STORMS IN SE OREGON AND THE HIGHER
TERRAIN OF SW IDAHO. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL.
WINDS WILL BE LIGHT... EXCEPT GUSTY IN THE VICINITY OF
THUNDERSTORMS.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY...MODELS AGREE THAT THE
WARM UPPER LEVEL RIDGE WILL GAIN STRENGTH AND SHIFT WEST TUESDAY AND
WEDNESDAY. THIS WILL BRING GRADUAL WARMING THROUGH THURSDAY AND A
DECREASING CHANCE OF THUNDERSTORMS...WITH ANY CONVECTION CONFINED TO
THE NORTHERN EDGE OF OUR CWA. TEMPERATURES WILL AVERAGE ABOUT 5
DEGREES ABOVE NORMAL. MODELS ARE STARTING TO HINT AT A PATTERN
CHANGE BY THE END OF THE WEEK...WITH THE NORTH PORTION OF THE RIDGE
SHIFTING EAST OF THE ROCKIES ON FRIDAY ALLOWING MORE PROGRESSIVE
WESTERLY FLOW ALOFT TO REACH IDAHO AND THE NORTHERN ROCKIES ON
SATURDAY. THIS WOULD MEAN CONTINUED DRY WEATHER WITH TEMPERATURES
POSSIBLY COOLING A FEW DEGREES NEXT WEEKEND.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...RED FLAG WARNING FROM 3 PM THIS AFTERNOON TO 9 PM MDT THIS
EVENING IDZ401>403.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...JB
AVIATION.....VM
PREV SHORT TERM...BW
PREV LONG TERM....MT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1044 AM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
&&
.PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LAKE BREEZE PSBL THIS AFTN. WIND SHIFT FROM LIGHT WEST OR
SOUTHWEST TO LIGHT EASTERLY.
* LOW CHANCE FOR SCATTERED SHRA/TSRA THIS AFTERNOON...BUT SOMEWHAT BETTER
CHANCES FAVORED MID/LATE EVENING AND EARLY TONIGHT.
JEE
//DISCUSSION...UPDATED 12Z...
TRICKY FORECAST THIS MORNING IN TERMS OF SHRA/TSRA CHANCES AND
WIND DIRECTION TRENDS. HIGH PRESSURE REMAINS OVER THE AREA BUT
WILL BE SLIDING SOUTHEASTWARD THROUGH THE DAY AS A COOL FRONTAL
BOUNDARY DROPS SOUTHWARD FROM ONTARIO AND EVENTUALLY CROSSES THE
AREA MONDAY. IN THE MEANTIME...AN UPPER LEVEL DISTURBANCE AND
ASSOCIATED MID LEVEL WARM ADVECTION GENERATED A SMALL SHRA/TSRA
COMPLEX WHICH IS NOW SHOWING SIGNS OF DECAY OVER NORTH-CENTRAL
IOWA. THIS WILL BE THE FIRST CHANCE FOR SHRA AT THE TERMINALS BUT
THERE MAY NOT BE MUCH LEFT OF IT BY MID MORNING WHICH IS WHEN IT
WOULD ARRIVE AT RFD. HAVE RETAINED VCSH MENTION AT RFD TO ACCOUNT
FOR THE POTENTIAL FOR SOME LIGHT RAIN OR SPRINKLES. SHOULD THIS
PRECIP HOLD TOGETHER IT WOULD REACH THE CHI AREA TERMINALS TOWARD
MIDDAY BUT HAVE A HARD TIME SEEING MUCH MORE THAN SOME LIGHT RAIN
OR SPRINKLES BY THEN. WARM ADVECTION WILL REMAIN IN PLACE ALOFT
WHICH MAY HELP TRIGGER SOME ISOLD/SCT DEVELOPMENT THIS AFTERNOON
BUT AM THINKING THAT THE BETTER CHANCES WILL ARRIVE THIS EVENING
AND EARLY TONIGHT AS THE LOW LEVEL JET INTENSIFIES TO THE WEST.
WILL CONTINUE WITH PROB30 FOR TS DURING THE EVENING HOURS WITH
SOME ACTIVITY POSSIBLE...BUT IT APPEARS THE BULK OF ANY ACTIVITY
WILL BE NORTH OF THE WISCONSIN BORDER. ADDITIONAL CHANCES WILL BE
IN PLACE MONDAY AS THE AFOREMENTIONED COLD FRONT CROSSES THE AREA
BUT THE EXTENT OF THE ACTIVITY WILL LIKELY DEPEND ON HOW ACTIVITY
EVOLVES TONIGHT SO WILL KEEP THE LATER PART OF THE 30 HR ORD TAF
DRY. THE FRONT MAY SLOW SO HAVE OPTED TO KEEP A SOUTHWEST WIND
MONDAY MORNING.
IN TERMS OF WINDS...WITH THE HIGH OVERHEAD MOST LOCATIONS HAVE
BEEN CALM OVERNIGHT WITH A FEW SITES STARTING TO REGISTER SOME
LIGHT WINDS. EXPECT A WEST TO WEST-NORTHWEST DIRECTION THIS
MORNING WITH SPEEDS REMAINING QUITE LIGHT. A LAKE BREEZE IS
EXPECTED TO DEVELOP LATE THIS MORNING AND MOVE INLAND TURNING
WINDS EASTERLY AND WILL CONTINUE WITH THE IDEA OF IT CROSSING
ORD/MDW LATER THIS AFTERNOON. THIS WILL NEED TO BE WATCHED CLOSELY
THOUGH BECAUSE AN INFLUX OF CLOUD COVER COULD PREVENT ITS
DEVELOPMENT AS COULD ANY SORT OF OUTFLOW FROM THE DECAYING
SHRA/TSRA COMPLEX. WINDS THEN TURN SOUTH TO SOUTHEAST THIS EVENING
RETURNING TO SOUTHWEST OVERNIGHT AS THE PRESSURE GRADIENT
TIGHTENS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM LOW CONFIDENCE IN LAKE BREEZE DEVELOPING AND CROSSING THE
TERMINALS THIS AFTERNOON.
* MEDIUM CONFIDENCE IN LOW CHANCE FOR SHRA/TSRA THROUGH THE
AFTERNOON THEN INCREASING CHANCES MID/LATE EVENING.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
701 AM CDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 649 AM CDT SUN AUG 11 2013
RADAR TRENDS SHOW THE PRECIPITATION THAT IS/WILL BE SKIRTING THE
NORTHERN CWFA IS MORE SHOWERS THAN STORMS. RAP TRENDS WITH THE
MCS...LIFT...AND HEAVY RAIN TOOLS INDICATE THE CURRENT NOCTURNAL
CONVECTION WILL MOVE THROUGH THE HWY 20 CORRIDOR AND SLOWLY
DISSIPATE AS IT ENCOUNTERS MORE DRY AIR AND MOVES AWAY FROM THE
BETTER SUPPORT.
A LULL IN ACTIVITY IS STILL EXPECTED LATE THIS MORNING AND EARLY
AFTERNOON BEFORE NEW DIURNAL CONVECTION DEVELOPS. THIS NEW
CONVECTION WILL LIKELY HOLD OFF UNTIL PEAK HEATING AS THE NEW 12Z
SOUNDING HAS THE CONVECTIVE TEMPERATURE IN THE MID 70S.
THE QUESTION THEN BECOMES HOW FAR SOUTH WILL THE NEW CONVECTION GO
INTO THIS EVENING AND OVERNIGHT. THE OVERALL FORCING IS WEAK IN
SPITE OF A WEAK FRONT/BOUNDARY MOVING THROUGH. THE BETTER CHANCES
STILL APPEAR TO BE NORTH OF I-80. ..08..
&&
.SYNOPSIS...
ISSUED AT 305 AM CDT SUN AUG 11 2013
06Z SFC ANALYSIS HAS A WEAK LOW NEAR KICR WITH A STATIONARY FRONT
SOUTHEAST INTO WESTERN IOWA. A WEAK BOUNDARY RAN FROM SOUTHEAST
SOUTH DAKOTA INTO NORTHERN IOWA. DEW POINTS WERE IN THE 50S ACROSS
THE GREAT LAKES WITH 60S IN THE PLAINS AND 70S ACROSS THE DEEP SOUTH
AND OHIO VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
THE MCS AND LIFT TOOLS WHEN APPLIED TO TRENDS IN THE RAP AND OTHER
MODELS SUGGEST A MAJORITY OF THE PRECIPITATION WILL REMAIN NORTH OF
THE CWFA THROUGH MID DAY WITH SOME SHOWERS BRUSHING THE NORTHERN
CWFA IN THE HIGHWAY 20 CORRIDOR. RECENT TRENDS WITH THE RAP SUGGEST
PRECIPITATION MAY NOT BEGIN ENTERING THE NORTHERN CWFA UNTIL AROUND
SUNRISE.
PRECIPITATION SHOULD WANE DURING THE LATE MORNING AND EARLY
AFTERNOON BEFORE RE-DEVELOPING THIS AFTERNOON HOURS DURING MAX
HEATING. ANY PRECIPITATION IN THE HWY 20 CORRIDOR WILL EXPAND
SOUTHWARD TO HWY 30 AND EVENTUALLY TO I-80 BY LATE AFTERNOON.
TONIGHT...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL BE ACROSS
ROUGHLY THE NORTHERN HALF OF THE CWFA DURING THE EVENING BEFORE
SLOWLY SPREADING SOUTH AFTER MIDNIGHT. THE EXTREME SOUTHERN PART OF
THE CWFA CURRENTLY LOOKS TO BE DRY BOTH TODAY AND TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN AUG 11 2013
RAIN CHANCES LINGER EARLY IN THE WEEK THEN MAINLY DRY AND PLEASANT
REST OF THE PERIOD WITH NEAR TO BELOW NORMAL TEMPS.
MON-MON NGT... SURFACE AND 850 MB COLD FRONTS WILL GRADUALLY SLIDE
THROUGH THE AREA AS AN UPPER LEVEL TROUGH MOVES INTO THE GREAT
LAKES. 850 MB BOUNDARY IS SUGGESTED TO BE PRIMARY PCPN MECHANISM
DUE TO BETTER CONVERGENCE WITH SCATTERED ELEVATED SHOWERS AND
ISOLD STORMS MAINLY NORTH OF I-80 MON AM SLIDING SOUTHEAST IN THE
PM. CONVERGENCE ALONG SURFACE FRONT FAIRLY WEAK BUT IF SUFFICIENT
HEATING INTO THE MID 80S THEN CAPPING INVERSION SHOULD WEAKEN AND
JUST ENOUGH CONVERGENCE TO ALLOW SCATTERED STORMS TO DEVELOP FROM
MID PM TO EARLY EVE MAINLY JUST S/SE OF QUAD CITIES. ENVIRONMENT
LOOKS LIKE FAIRLY WEAK TO MARGINAL SHEAR (0-6KM BULK SHEAR 20-25 KTS)
AND MODERATE INSTABILITY (MUCAPES 1500-2000+ J/KG)... THUS MARGINAL
ISOLD PULSE TYPE STORMS SUGGESTED WITH SOME SMALL HAIL AND DOWNBURST
WINDS POSSIBLE. BANKING ON ANY PCPN MAINLY SCATTERED AND ENOUGH
BREAKS IN CLOUDS TO YIELD WIDESPREAD 80S FOR HIGHS WITH THE WARMEST
READINGS ACROSS THE SOUTHERN CWA. RAIN CHCS LINGER MON EVE ACROSS THE
SOUTH...THEN HIGH PRESSURE RIDGE BEGINS TO BUILD IN OVRNGT BRINGING IN
DRIER AIR. LOWS MON NGT COOLEST NORTH WHERE SOME 50S WHILE 60S ARE
LIKELY ELSEWHERE.
TUE-TUE NGT... UKMET IS AN OUTLIER HOLDING UP MID LEVEL BAROCLINIC
ZONE ACROSS SOUTHERN CWA AND GENERATING SOME ADDITIONAL PCPN ON TUE.
HAVE SIDED TOWARD CONSENSUS FCST WITH CONTINUED DRY AND COOL
ADVECTION WITH STRENGTHENING NORTHWEST FLOW ALOFT AND INCOMING SURFACE
RIDGE SHUNTING BAROCLINIC ZONE AND PCPN PROCESSES SOUTH/WEST OF THE
CWA. HIGHS TUE RANGING FROM SOME MID 70S NORTH TO LOWER 80S SOUTH WITH
PT-MOSUNNY SKIES. CONTINUED LOWERING OF DEWPTS MAINLY INTO THE 50S
COUPLED WITH N/NE WINDS 5-10 MPH SHOULD MAKE FOR A REAL NICE AND
VERY COMFORTABLE DAY FOR OUTDOOR ACTIVITIES. COOL CONDITIONS EXPECTED
TUE NGT WITH CLEARING SKIES AND LIGHT WINDS ALLOWING FOR WIDESPREAD
LOWS IN THE 50S.
WED-SAT...FLOW ALOFT WILL REMAIN NORTHWEST WITH LARGE EXPANSE OF HIGH
PRESSURE AT THE SURFACE SLOWLY SHIFTING FROM THE UPPER MIDWEST INTO
THE OH VLY. RESULT WILL BE A PROLONGED PERIOD OF FANTASTIC WX FEATURING
LOW HUMIDITY...LIGHT WINDS...MAINLY CLEAR SKIES AND SLIGHTLY BELOW
NORMAL TEMPS WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S AND LOWS IN
THE 50S TO AROUND 60F.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 649 AM CDT SUN AUG 11 2013
THE CURRENT NOCTURNAL CONVECTION IS MORE SHRA THAN TSRA. THERE
SHOULD BE A VCSH FOR KDBQ THROUGH MID MORNING BEFORE ALL ACTIVITY
DISSIPATES. SO...VFR WX STILL LOOKS ON TAP THROUGH 06Z/12. NEW
CONVECTION IS EXPECTED TO DEVELOP BY 21Z/11 THAT MAY RESULT IN
BRIEF MVFR CONDITIONS AT A TAF SITE. SHRA/TSRA WILL CONTINUE AFT
SUNSET WITH KDBQ POSSIBLY EXPERIENCING MVFR CONDITIONS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS JACKSON KY
1048 AM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 1047 AM EDT SUN AUG 11 2013
MADE A FEW UPDATES TO THE INHERITED FORECAST. REMOVED THE PRE-FIRST
PERIOD THAT WAS INCLUDED WITH THE 4 AM FORECAST PACKAGE...AND REMOVED
MENTION OF EARLY MORNING FOG. THE HIGHER PRECIPITATION CHANCES FROM
EARLIER THIS MORNING WERE ALSO REMOVED FROM THE TODAY PERIOD...AS THE
AREA IS CURRENTLY EXPERIENCING A LULL IN SHOWERS AND STORMS.
HOWEVER...WITH A SLUGGISH FRONTAL BOUNDARY MEANDERING ABOUT ACROSS
THE AREA...ANTICIPATE THAT SHOWERS AND STORMS WILL AGAIN INCREASE IN
COVERAGE AS THE DAY WEARS ON...PARTICULARLY ALONG AND SOUTH OF THE
HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDOR. LOCALLY HEAVY RAINFALL
WILL REMAIN A POSSIBILITY THROUGHOUT THE DAY WHERE MORE WIDESPREAD
SHOWERS AND STORMS OCCUR.
UPDATE ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO OUT OF SORTS IN THIS PATTERN TO
BITE ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE
RUN. DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A
THREAT FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 730 AM EDT SUN AUG 11 2013
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH SOUTHEAST KENTUCKY THIS MORNING. THE LOWER CIGS AND VSBY
WILL CONTINUE TO BE HIT AND MISS THROUGH THE MORNING. AN IMPROVEMENT
TO VFR SHOULD TAKE PLACE BY LATE MORNING. SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE AT JUST ABOUT ANY POINT THROUGH THE
DAY. TONIGHT...DO EXPECT SOME LOWER VIS AND CIGS DUE TO FOG AS THE
FROM FINALLY SINKS SOUTH OF THE TAF SITES. WINDS WILL BE LIGHT AND
VARIABLE DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
730 AM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO SQUIRRELLY IN THIS PATTERN TO BITE
ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE RUN.
DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A THREAT
FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 730 AM EDT SUN AUG 11 2013
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH SOUTHEAST KENTUCKY THIS MORNING. THE LOWER CIGS AND VSBY
WILL CONTINUE TO BE HIT AND MISS THROUGH THE MORNING. AN IMPROVEMENT
TO VFR SHOULD TAKE PLACE BY LATE MORNING. SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE AT JUST ABOUT ANY POINT THROUGH THE
DAY. TONIGHT...DO EXPECT SOME LOWER VIS AND CIGS DUE TO FOG AS THE
FROM FINALLY SINKS SOUTH OF THE TAF SITES. WINDS WILL BE LIGHT AND
VARIABLE DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
734 AM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EDT SUN AUG 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WRLY FLOW THROUGH THE NRN
GREAT LAKES ON THE SRN FLANK OF A MID/UPPER LEVEL TROUGH EXTENDING
FROM HUDSON BAY TO NEW FOUNDLAND. A WELL-DEFINED UPSTREAM SHORTWAVE
TROUGH LOCATED NEAR THE NW CORNER OF MN SUPPORTED A BAND OF LIGHT
SHOWERS OVER N CNTRL MN. THE HEAVIER SHRA/TSRA REMAINED WELL TO THE
SOUTH FROM SE SD AND SW MN INTO NW IA ALONG THE 850 MB FRONT. AT THE
SFC...A WEAK TROUGH AHEAD OF THE MID LEVEL SHRTWV EXTENDED FROM NEAR
CYQT NRN MN. IR LOOP SHOWED MAINLY CLEAR SKIES OVER UPPER MI WITH
MID CLOUDS APPROACHING FROM NE MN.
TODAY...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE TIMING OF
THE SHRTWV ACROSS THE AREA BRINGING THIS FEATURE INTO CNTRL UPPER MI
AROUND 18Z AND QUICKLY TO LAKE HURON BY 00Z. THE COMBINATION OF THE
WEAK 700-300 MB QVECTOR CONV WITH THE SHRTWV AND LOW LEVEL CONV
ALONG THE TROUGH AND LAKE BREEZE BOUNDARIES SHOULD BE ENOUGH TO
SUPPORT AT LEAST SUPPORT ISOLD/SCT PCPN. MLCAPE VALUES TO AROUND 400
J/KG...PER NAM...WILL BE MARGINAL FOR TSRA BUT WITH THE ARRIVAL OF
THE SHRTWV DURING PEAK HEATING ISOLD TSRA WILL ALSO BE POSSIBLE.
TONIGHT...ANY SHRA/TSRA THAT DEVELOP DURING THE AFTERNOON WILL
DIMINISH WITH THE LOSS OF DAYTIME HEATING AND THE DEPARTURE OF THE
SHRTWV. A SLIGHT CHANCE FOR SHOWERS WAS MENTIONED AS ANOTHER WEAK
SHRTWV AND SFC MOVES THROUGH UPPER MI. EVEN THOUGH MOISTURE IS
LIMITED...SUCH WEAK DISTURBANCES IN THE BROAD CYCLONIC FLOW PATTERN
HAVE OFTEN MANAGED TO SUPPORT ISOLATED LIGHT SHOWERS.
HOWEVER...CONFIDENCE IN TIMING/POSITION OF ANY PCPN IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 316 AM EDT SUN AUG 11 2013
A QUIET WEEK IS IN THE MAKING FOR UPPER MICHIGAN AS HIGH PRESSURE
ANCHORS ITSELF OVER THE WESTERN GREAT LAKES. MOSTLY CLEAR SKIES
SHOULD BE THE RULE...THOUGH A SERIES OF WEAK SHORTWAVES COULD BE A
BIT PESKY WITH CLOUDS AROUND MID-WEEK. TEMPERATURES WILL SLOWLY WARM
TO NEAR NORMAL...WITH SEVERAL CHILLY NIGHTS
EXPECTED...ESPECIALLY TUESDAY NIGHT.
MONDAY AND MONDAY NIGHT...THE MAIN AXIS OF AN EASTERN CANADIAN
TROUGH WILL BE APPROACHING THE AREA AT THE START OF THE PERIOD.
MODEL GUIDANCE HAS STRUGGLED WITH MAINTAINING A STEADY APPROACH TO
THE STRUCTURE OF THIS TROUGH AXIS. THERE ARE SEVERAL DISTINCT AXES
EMBEDDED IN THE MAIN TROUGH...AND EACH SHOULD SWING THROUGH THE CWA
IN ABOUT 12 HOUR INTERVALS STARTING MONDAY MORNING. THE MAIN PLAYER
IN THIS SERIES IS CURRENTLY MOVING SSW INTO FAR NORTHWEST HUDSON BAY
AROUND THE WESTERN PERIPHERY OF AN IMPRESSIVE VORT MAX OVER CENTRAL
HUDSON BAY. BOTH ARE CLEARLY APPARENT IN WATER VAPOR SAT...SO SEE NO
REASON TO QUESTION MODEL PERFORMANCE WITH TIMING. THE TROUGH SHOULD
BE OVER WESTERN LAKE SUPERIOR BY 18Z MONDAY...AND EASTERN UPPER MI
AT 00Z TUESDAY. MID-LEVEL SUPPORT WILL BE PRESENT WITH MODEST H5
Q-VECTOR CONVERGENCE AND H7 FRONTOGENESIS. A SUBSIDENCE INVERSION
AROUND 600MB BEHIND SUNDAYS SYSTEM AND DRIER AIR BEHIND THE SFC
FRONT WILL LIMIT PCPN COVERAGE. LAKE BREEZE CONVERGENCE WILL ASSIST
PCPN DEVELOPMENT...BUT STABILIZING NW GRADIENT FLOW SHOULD CONFINE
BEST COVERAGE TO THE SOUTH-CENTRAL AND ALONG LAKE MI. THUNDER
POTENTIAL WILL BE MINIMAL WITH MUCAPE STRUGGLING TO REACH 500 J/KG
NORTH OF GRB. MOST OF THIS CAPE WILL BE BELOW THE 0C LEVEL...SO KEPT
THUNDER AT SLIGHT CHANCE OVER JUST THE SOUTH CENTRAL CWA.
MONDAY NIGHT AND TUESDAY...ANY PRECIP WILL DIMINISH WITH THE PASSAGE
OF AN ASSOCIATED SFC TROUGH AND LOSS OF DAYTIME HEATING MONDAY
EVENING. A SECOND MID-LEVEL WAVE CLOSER ASSOCIATED WITH THE MAIN
TROUGH AXIS WILL BE CROSSING THE CWA BY 12Z TUESDAY. THE NAM AND
ECMWF ARE A BIT SLOWER WITH THIS TROUGH AND ACTUALLY KICK OFF SOME
LIGHT SHOWER ACTIVITY ACROSS THE INTERIOR CENTRAL AND EAST TUESDAY
MORNING. WITH THE ATMOSPHERE QUITE DEPLETED OF MOISTURE AS NOTED BY
PWATS OF ONLY 0.7 INCHES...DO NOT EXPECT MUCH MORE THAN SOME
MID-LEVEL CLOUDINESS WITH MAYBE A FEW SPRINKLES. THIS DOES MAKE MIN
TEMPS FOR MONDAY NIGHT A LITTLE HARDER TO PIN DOWN. GIVEN THE
UNCERTAINTY IN MID-CLOUD COVER...OPTED NOT TO CHANGE MUCH AND LEAVE
TEMPS RANGING FROM THE MID 40S INTERIOR WEST TO THE LOW 50S ALONG
THE SHORE. QUITE A COOL TUESDAY WILL FOLLOW UNDER H8 TEMPS OF ONLY 4
TO 7C...COOLEST EAST. MIXING SHOULD REACH THE H8 LEVEL...SO TEMPS
ARE EXPECTED TO APPROACH 70F SOUTH CENTRAL. AN EXCELLENT MODIS SST
CAPTURE TODAY SHOWS LAKE TEMPS AROUND 50F IN THE NORTHERN OPEN
WATERS...AND MID 50S IN THE REMAINDER OF THE OPEN WATERS. SO EVEN
WITH A NORTH WIND...THE COASTAL AREAS SHOULD BE ABLE TO BREAK INTO
THE LOW 60S.
TUESDAY NIGHT THROUGH THURSDAY...SFC HIGH PRESSURE WILL SETTLE OVER
WESTERN UPPER MI TUESDAY NIGHT AS MID-LEVEL RIDGING ATTEMPTS TO
BUILD EASTWARD INTO THE UPPER MS VALLEY. LOW PWAT UNDER 0.5 INCHES
AND LIGHT WINDS WILL LEAD TO EXCELLENT RADIATIONAL COOLING.
CONTINUED USING A BLEND OF GUIDANCE THAT HAS PERFORMED WELL ON
SIMILAR NIGHTS OVER THE PAST FEW WEEKS. EXPECT 40S FOR ALL BUT THE
IMMEDIATE SHORE. SOME TYPICAL INTERIOR WEST COLD SPOTS COULD EVEN
SEE UPPER 30S.
A THIRD WAVE WILL SKIM THE NE CWA WEDNESDAY MORNING. LITTLE MOISTURE
AND MINIMAL LIFT WILL BRING ONLY SCATTERED MID-CLOUDS. ANOTHER WAVE
WILL FOLLOW THE SAME TRACK ON THURSDAY...BUT WILL SUCCUMB TO THE
SAME LIMITING FACTORS. CLOUDINESS SHOULD BE A LITTLE MORE AS LIMITED
MOISTURE RETURN BEGINS ON THE BACKSIDE THE SFC RIDGE.
FRIDAY AND SATURDAY...MODEL GUIDANCE IS SHOWING A TROUGH DROPPING SE
OVER NORTHERN ONTARIO LATE FRIDAY INTO SATURDAY. THOUGH GUIDANCE IS
SHOWING MORE CONSISTENCY...WILL CONTINUE CONSENSUS APPROACH TO
PRECIP CHANCES FOR NOW...WHICH SHOULD BE LIMITED TO SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 733 AM EDT SUN AUG 11 2013
EXPECT VFR CONDITIONS THIS FCST PERIOD AT ALL THREE TAF SITES. A
PASSING DISTURBANCE MAY CAUSE SOME -SHRA THIS AFTN IN THE PRESENCE
OF DAYTIME HEATING AT SAW AND PERHAPS IWD...BUT CONFIDENCE IS TOO LOW
TO INCLUDE MORE THAN VCSH IN THE TAFS. ANY -SHRA WILL END BY
SUNSET WITH THE ONSET OF NOCTURNAL COOLING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EDT SUN AUG 11 2013
A SERIES OF WEAK TROUGHS WILL MOVE THROUGH LAKE SUPERIOR THROUGH
MONDAY. HOWEVER...WINDS ARE EXPECTED TO REMAIN LESS THAN 20 KNOTS.
HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT LAKES TUESDAY
THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
1027 AM CDT SUN AUG 11 2013
.UPDATE...
THE FOCUS ON THIS UPDATE IS ON CLOUD COVER AND PCPN TRENDS THROUGH
THIS EVENING. THE MODELS ARE SUGGESTING THAT SCATTERED/BROKEN
CUMULUS CLOUDS WILL DEVELOP IN OUR COOL WNW FLOW EARLY THIS
AFTERNOON WHEN WE GET CLOSER TO PEAK HEATING AND AFTER SOME OF THE
REMAINING MID TO HIGH LEVEL CLOUDS FROM THIS MORNING DISSIPATE OR
MOVE OUT OF THE FORECAST AREA. THE HRRR AND SREF...INCLUDING SOME
OTHER MODELS...ARE SUGGESTING THERE MAY BE SOME SHOWERS AND/OR
SPRINKLES AMIDST THE SCT/BKN CUMULUS. THEREFORE...I ADDED SOME
MENTION OF SHOWERS OVER MOST OF THE NORTHLAND FOR THIS AFTERNOON.
THERE MAY ALSO BE SOME WEAK THUNDERSHOWERS.
.AVIATION...12Z TAF ISSUANCE...
UPPER LEVEL SYSTEM WILL CROSS CWA TODAY WITH SHOWERS POSSIBLE AT
TIMES. CEILINGS SHOULD REMAIN VFR EXCEPT NEAR KINL WHERE MVFR
MAY DEVELOP THIS MORNING AND INTO THE EARLY AFTERNOON. SFC HIGH
BUILDS INTO REGION OVERNIGHT HOWEVER MAY SEE LINGERING VFR
CEILINGS NEAR 5K TO 7K FEET ACROSS SOME TERMINALS.
&&
.PREV DISCUSSION... /ISSUED 703 AM CDT SUN AUG 11 2013/
UPDATE....
SHOWERS ARE SLIGHTLY MORE NUMEROUS THAN THOUGHT SO MADE SOME
SLIGHT ADJUSTMENTS TO RAISE POPS SLIGHTLY.
PREV DISCUSSION... /ISSUED 330 AM CDT SUN AUG 11 2013/
SHORT TERM...
THE UPPER LEVEL LOW PRESSURE TROUGH CENTERED OVR EASTERN CANADA AND
STRETCHING ACROSS THE GREAT LAKES WILL PRODUCE SOME MORE SHOWERS
TODAY. A COUPLE MORE S/WVS WILL ROTATE THROUGH THE TROF TODAY.
CURRENT WV LOOP DEPICTS THE S/WV INTO NWRN MN.. AND HAS RESULTED
IN SOME VERY LIGHT SHOWERS ACROSS NORTHERN MN. THIS WAVE WILL
ROTATE SEWRD ACROSS THE CWA...AND HAVE GIVEN SMALL POPS FOR THE
REGION. EXPECT SHOWERS TO BE MAINLY THIS MORNING IN THE FAR
NORTH...AND NOT BEGIN TIL MID TO LATE MORNING IN NWRN WI. HAVE
INTRODUCED SOME THUNDER LATER TODAY WITH FAIRLY STEEP LOW LEVEL
LAPSE RATES LATER THIS MORNING AND AFTERNOON AND LI`S DOWN TO -2.
EXTENDED...MONDAY THROUGH SATURDAY...
AN UNUSUALLY STRONG MID LVL VORTEX OVER CTRL ONTARIO WILL PUSH A SFC
COLD FRONT ACROSS THE REGION MONDAY. A CYCLONICALLY CURVED FLOW
COMBINED WITH SUFFICIENT DEEP LAYER MOISTURE WILL CREATE SHOWER
POTENTIAL OVER THE NRN/ERN PARTS OF THE CWA. FOR THE REMAINDER OF
THE WEEK THE ANOMALOUS ONTARIO MID LVL TROF WILL MOVE EAST.
INCREASING RIDGING ALOFT WILL ALLOW A LARGE SFC HIGH TO EXPAND
FROM THE SRN PLAINS OF CANADA INTO THE LOWER GT LAKES. A PERIOD OF
QUIET WX IS EXPECTED TUES THROUGH THUR AS SUBSIDENCE SFC/ALOFT
DOMINATES MOST OF THE REGION. THE ONLY POSSIBLE EXCEPTION WOULD BE
OVER ERN ARROWHEAD CLOSER TO EASTERN VORTEX. CONFIDENCE IN FCST
DECREASES BY FRIDAY AS GEM/GFS/ECMWF DISAGREE ON MID LVL FLOW
EVOLUTION. AS WAS THE CASE IN PREVIOUS GRIDS/FCST WILL CARRY SOME
LOW POPS BEGINNING FRIDAY...AND INTO THE WEEKEND. THE CONSENSUS IS
THAT A WARMING TREND IS APPEARING MORE LIKELY FOR THE WEEKEND AS
UPPER HEIGHTS BUILD AND 925/85 TEMP VALUES RISE ABOVE WHAT WE HAVE
EXPERIENCED IN A WHILE. 85H MSTR TRANSPORT AMONG THE MED RANGE MDLS
SUGGESTS ENOUGH MOISTURE WILL BE AVAILABLE FOR CONVECTION
SAT/SUNDAY. OVERALL SYNOPTIC SCALE PATTERN THIS WEEKEND WOULD
SUGGEST INCREASING POSSIBILITY OF MCS GENERATION OVER SRN
SASK/MAN...MOVING SE TOWARDS CWA. TOO MANY UNCERTAINTIES TO
HIGHLIGHT MAGNITUDE/AREAL COVERAGE OF POTENTIAL STRONG/SVR STORMS.
TEMPS WILL AVERAGE BLO CLIMO MOST OF THE WEEK AND THEN NEAR/ABOVE
CLIMO FOR THE WEEKEND.
&&
.POINT TEMPS/POPS...
DLH 76 54 72 49 / 20 10 10 0
INL 71 48 71 45 / 30 20 20 0
BRD 78 52 76 50 / 20 10 10 0
HYR 76 50 74 47 / 20 10 10 0
ASX 76 52 71 48 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS JACKSON MS
1000 AM CDT SUN AUG 11 2013
.UPDATE...MID LEVEL WEST TO EAST ORIENTED RIDGE AXIS CONTINUES
ACROSS THE CWA. SURFACE ANALYSIS STILL HAS HIGH PRESSURE OVER THE
WESTERN ATLANTIC RIDGING WEST OVER THE GULF COAST STATES. THIS LIGHT
SOUTHERLY LOW LEVEL FLOW WAS HELPING MAINTAIN OUR +2IN PW AIRMASS.
HEATING THIS MORNING WAS ON TRACK AND A CU FIELD WAS ALREADY NOTED
OVER OUR SOUTHEAST ZONES SPREADING NORTH. THIS IS WHERE HI-RES
MODELS SUGGEST CONVECTION WL INITIATE GOING INTO THE AFTERNOON.
SCATTERED COVERAGE IS STILL EXPECTED AND OVERALL FORECAST REMAINS ON
TRACK FOR TODAY. A FEW STRONG STORMS WILL BE HARD TO RULE OUT BUT
WET MICROBURST POTENTIAL WILL BE LOW AGAIN TODAY. /22/
&&
.AVIATION...CONVECTION HAS GOTTEN AN EARLY START TODAY AS SOME
ISOLATED SHOWERS HAVE DEVELOPED AND ARE LIFTING NORTH OVER EAST
CENTRAL AND SOUTHEAST MISSISSIPPI...KMEI AND KHBG. WHILE VFR
CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TAF SITES THROUGH THE
COURSE OF THE DAY...SCATTERED CONVECTION IS FORECAST TO DEVELOP AS
WE HEAT UP AND OUR ATMOSPHERE DESTABILIZES. SITES THAT OBSERVE
CONVECTION WITHIN THEIR RESPECTED AERODROMES TODAY WILL LIKELY
EXPERIENCE A BRIEF BOUT OF MVFR/IFR FLIGHT STATUSES DUE TO DEGRADED
VISIBILITIES AND/OR CEILINGS. WIND GUSTS IN THE 26-34 KNOT RANGE
ARE ALSO POSSIBLE WITH THE MOST INTENSE STORMS. SUSTAINED WINDS
AWAY FROM CONVECTION TODAY WILL BE SOUTHEASTERLY BETWEEN 3-8 KNOTS.
SHOWERS AND STORMS WILL GRADUALLY DIMINISH THROUGH THE EVENING HOURS
AND VFR CONDITIONS WILL CONTINUE INTO THE NIGHT. WINDS WILL ALSO
SUBSIDE DURING THIS TIME...BECOMING LIGHT TO CALM OVERNIGHT INTO
MONDAY MORNING. PATCHY FOG AND LOW STRATUS WILL BE POSSIBLE
OVER MAINLY EAST AND SOUTHEAST MISSISSIPPI...KGTR...KMEI...AND
KHBG. THIS COULD AGAIN BRIEFLY REDUCE CEILINGS AND/OR VISIBILITIES
TO MVFR/IFR STATUS AROUND SUNRISE MONDAY. /19/
$$
.PREV DISCUSSION... /ISSUED 402 AM CDT SUN AUG 11 2013/
SHORT TERM...TODAY THROUGH MONDAY NIGHT...SEASONAL WEATHER FOR MID
AUGUST WILL BE THE NAME OF THE GAME ACROSS THE ARKLAMISS THROUGH THE
FIRST PART OF THE WORK WEEK. THE "FLAT" UPPER RIDGE THATS BEEN IN
PLACE ACROSS THE SOUTHEASTERN CONUS WILL REMAIN THE MAIN STORY
THROUGH THE SHORT TERM. THE AIRMASS IS QUITE SOUPY AS PW VALUES HAVE
CLIMBED ABOVE 2 INCHES AND LOOK TO REMAIN IN EXCESS OF 2 IN FOR THE
NEXT FEW DAYS. MOSTLY CLEAR SKIES THIS MORNING WILL GIVE WAY TO
DECENT SHOWER AND THUNDERSTORM COVERAGE THIS AFTERNOON/EARLY EVENING
AS THE BOUNDARY LAYER HEATS UP. LATEST HRRR RUNS SUGGEST THE BEST
STORM COVERAGE EARLY ON WILL BE SOUTH OF THE NATCHEZ TRACE WITH
COVERAGE EXPANDING FURTHER NORTH AS TIME WEARS ON. LATEST LOCAL WRF
AND ASSOCIATED NAM GUIDANCE SUGGESTS BETTER COVERAGE ACROSS NORTHERN
ZONES EARLY ON BEFORE COVERAGE INCREASES ACROSS THE SOUTH IN THE
AFTERNOON AS THE SEA BREEZE WORKS ITS WAY IN. NEEDLESS TO SAY THERE
IS STILL SOME UNCERTAINTY IN THE DETAILS OF HOW TODAY WILL EVOLVE
ALTHOUGH I DO LIKE THE HRRR SOLUTION AT THIS POINT. LAPSE RATES LOOK
RATHER MEAGER ONCE AGAIN TODAY/SIMILAR TO YESTERDAY/AND WILL
HIGHLIGHT THE RISK OF A FEW STRONG STORMS IN THE HWO FOR THE
AFTERNOON...NOTHING TOO SIGNIFICANT. VERY WEAK FLOW IN THE
ATMOSPHERE WILL YIELD VERY SLOW STORM MOTIONS WHICH WILL ENHANCE THE
RISK FOR LOCALLY HEAVY RAINS AND FLOODING...WE`LL BE KEEPING AN EYE
ON THAT TODAY. A BLEND OF GFS MOS WITH THE COOLER NAM GUIDANCE GAVE
REASONABLE LOOKING HIGHS FOR TODAY IN THE LOW/MID 90S. ITS FEASIBLE
A FEW AREAS THAT SEE SOME CONVECTION EARLY ON AND HANG ON TO SOME
CLOUD COVER THROUGH THE DAY WILL STRUGGLE TO REACH 90.
CONVECTION WILL WANE THIS EVENING USHERING IN ANOTHER QUIET NIGHT
TONIGHT WITH LOWS FALLING INTO THE LOW/MID 70S. A REPEAT PERFORMANCE
OF TODAY LOOKS IN STORE FOR TOMORROW WITH CONVECTION EXPANDING IN
COVERAGE THROUGH THE AFTERNOON...BEFORE DIMINISHING DURING THE
EVENING. TEMPS WILL BE SIMILAR TO TODAY WITH HIGHS IN THE LOW/MID
90S/OVERNIGHT LOWS TUE MORNING IN THE LOW/MID 70S. /BK/
LONG TERM...TUESDAY THROUGH SUNDAY...THE GLOBAL MODELS CONTINUE TO
BE IN DECENT AGREEMENT AND SUPPORT THE PATTERN CHANGE THAT WILL
BRING WETTER AND COOLER CONDITIONS TO THE REGION.
AS WE HEAD INTO MID WEEK...THE FLAT MID/UPPER RIDGE WILL GIVE WAY TO
MORE OF A NW FLOW TYPE PATTERN. THIS WILL ALLOW A SFC FRONT TO
STEADILY MAKE ITS WAY INTO THE REGION BY THU. AHEAD OF THE FRONT
LOOK FOR AN ACTIVE CONVECTIVE REGIME TO DEVELOP AS DEEP LIFT AND LOW
LEVEL MOISTURE CONVERGENCE INCREASE. IT APPEARS THERE WILL BE
MULTIPLE OPPORTUNITIES FOR PRECIP BETWEEN TUE AND WED NIGHT WITH
SOME HEAVY RAINFALL POSSIBLE. A WIDESPREAD 1-2 INCHES IS LOOKING
LIKELY WITH LOCALIZED 2-4 POSSIBLE DURING THIS PERIOD. TIMING RAIN
EPISODES WILL BE TOUGH AS CHANCES WILL BE QUITE HIGH FOR EITHER DAY
OR NIGHT PERIODS. GFS POPS WERE PRETTY HIGH AND MOST OF THAT WAS
ACCEPTED. HOWEVER...ADJUSTMENTS WERE MADE BASED OFF EURO MODEL DATA
AND TIMING. AT THIS TIME (REMEMBER ITS STILL DAY 3-4) POPS WILL
RANGE FROM 50-70% DURING THE TUE-WED NIGHT PERIODS WITH THE SOME OF
THE BEST RAIN POTENTIAL FOCUSED ON WED. WHILE I MENTIONED THE MODELS
WERE IN DECENT AGREEMENT...THIS LATEST RUN OF THE GFS WAS A BIT
SLOWER AND THIS RESULTED IN SUBSTANTIALLY HIGH POPS FOR NORTHERN
SECTIONS OF THE AREA WED NIGHT. WHILE THERE IS UNCERTAINTY IN HOW
THE SYSTEM/PRECIP WILL EVOLVE...MORE WEIGHT WAS GIVEN TO THE TIMING
OF THE EURO DO TO ITS CONSISTENCY. AS A RESULT...POPS WERE LOWERED
LOWERED ACROSS THE NORTH TO FIT THE EURO TIMING AND STAY MORE IN
LINE WITH PREV FORECASTS.
BY THU...A MORE AMPLIFIED PATTERN WILL HELP PUSH THE SFC BOUNDARY
THROUGH THE CWA ALONG WITH THE DEEPER MOISTURE. AS A RESULT...PRECIP
POTENTIAL WILL BE ON THE DEGREASE. AGAIN...THE SLOWER GFS HELD ONTO
POPS MORE AND VALUES WERE TAPERED BACK TO MATCH MORE OF THE EURO.
GENERALLY DRIER CONDITIONS WILL EXIST FOR THE FRI-SUN PERIODS.
AS FOR TEMPS...COOLER READINGS ARE EXPECTED AND FOR THE MOST
PART...GUIDANCE IS SUPPORTING THIS. THE MAIN ISSUE IS ON TUE WHERE
THE GFS IS QUITE WARM. ENSEMBLE MOS ALONG WITH THE EURO AND NAM ARE
MUCH COOLER. THE COOLER SCENARIO FITS BETTER AS CLOUDS AND A EARLIER
START TO THE PRECIP ARE EXPECTED. DUE TO THIS...HIGH TEMPS WERE CUT
SOME 3-5 DEGREES. A SIMILAR SITUATION EXISTS ON WED. THE GFS IS
LOWER WITH TEMPS...BUT AGAIN IS THE WARM OUTLIER COMPARED TO THE
ENSEMBLE MOS AND EURO. WED COULD ACTUALLY BE SUBSTANTIALLY LOWER
THAN CLIMO WITH LOWER/MID 80S A REAL POSSIBILITY FOR HIGHS. WHILE I
DID NOT GET THAT AGGRESSIVE...TEMPS WERE CUT TO FIT A RANGE OF 86-89.
FOR THU-SUN...BELOW AVG CONDITIONS LOOK TO BE THE RULE AND THIS IS
SUPPORTED BY ALL EXTENDED MOS/MODEL DATA. /CME/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 91 72 91 73 / 53 30 55 28
MERIDIAN 91 71 90 72 / 58 30 54 38
VICKSBURG 91 73 92 71 / 50 30 49 24
HATTIESBURG 92 74 92 74 / 51 28 63 40
NATCHEZ 90 73 91 73 / 50 26 60 31
GREENVILLE 93 74 92 74 / 50 30 44 27
GREENWOOD 92 73 91 73 / 50 30 49 29
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
22/19/BK/CME
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
958 AM MDT SUN AUG 11 2013
.UPDATE...
OVERALL FORECAST IN GOOD SHAPE. MAIN CHANGE WAS TO INCREASE POPS
THIS AFTERNOON IN RESPONSE TO NAM SHOWING A BETTER CHANCE OF
THUNDERSTORMS EARLY THIS AFTERNOON. NAM PICKED UP ON A WEAK VORT
CENTER DRIFTING OVER CENTRAL AREAS THIS MORNING HEADING INTO
SOUTHEAST MONTANA BY MID DAY. SATELLITE ALREADY SHOWING SOME MID
LEVEL CONVECTION WITH A FEW WEAK RADAR RETURNS OVER ROSEBUD
COUNTY. DO THINK THAT THIS ENERGY WILL GENERATE MORE CONVECTION
OVER NORTHEAST WYOMING THAN SOUTHEAST MONTANA BUT ENOUGH THERE TO
MENTION SLIGHT CHANCE OF STORMS. MAIN FOCUS THIS AFTERNOON WILL BE
A SHORTWAVE EMBEDDED IN DIFFLUENT SOUTHERLY FLOW MOVING INTO
SOUTHWEST/SOUTH CENTRAL MONTANA. MODELS IN GOOD AGREEMENT
DEVELOPING AN AREA OF CONVECTION OVER SOUTHWEST
MOUNTAINS...PUSHING NORTHEAST THROUGH THE LATE AFTERNOON AND
EVENING...SIMILAR TO LAST NIGHT. MOISTURE IS A BIT MORE LIMITED
TODAY OVER WESTERN ZONES SO THREAT FOR STRONG WIND GUSTS IS
GREATER THAN YESTERDAY. ONCE STORMS MOVE OFF THE MOUNTAINS AND
INTO THE LOWER ELEVATIONS MORE MOISTURE IS AVAILABLE FOR RAIN AND
SMALL HAIL. AS WAS THE CASE YESTERDAY THERE COULD BE A BRIEF
SEVERE STORM WITH LARGER HAIL DUE TO CELL MERGER/BOUNDARY
COLLISION...BUT OVERALL THE MAIN THREAT WILL BE GUSTY WINDS.
SREF/SSEO SOLUTIONS KEEP CONVECTION GOING OVER NORTHERN ZONES LATE
IN THE EVENING ACROSS NORTHERN ZONES...WITH A BIT OF AN ELEVATED
STRONG TO SEVERE THREAT AROUND MIDNIGHT OVER NORTHEAST ZONES. WILL
SEE IF THIS CONTINUES WITH LATEST MODEL RUNS AND MAY INCREASE
POPS AND MENTION STRONGER STORMS FOR THIS AREA WITH AFTERNOON
PACKAGE. TEMPERATURES LOOK PRETTY GOOD...BUT THERE IS AN AREA OF
DENSE SMOKE ALOFT MOVING OUT OF NORTH CENTRAL MONTANA TOWARD THE
SOUTHEAST. THIS COULD LIMIT HEATING BY A FEW DEGREES THIS
AFTERNOON CENTRAL AND EAST. CHAMBERS
&&
.SHORT TERM...VALID FOR TDY AND MON...
A BROAD 500-HPA RIDGE WILL KEEP A WARMING TREND GOING THE NEXT FEW
DAYS...BUT WEAK IMPULSES CUTTING THROUGH THE RIDGE WILL ALSO BRING
SOME CHANCES OF STORMS TO THE REGION AS WELL.
FIRST OF ALL...THE BOUNDARY LAYER IN SOUTHEASTERN MT IS VERY CLOSE
TO SATURATION AS OF 09 UTC...AND STRATUS IS BEGINNING TO FORM OVER
THE DAKOTAS AND AS FAR WEST AS BAKER. GIVEN WEAK EASTERLY GRADIENT
WINDS THROUGH THE MORNING...WE EXPECT STRATUS TO CONTINUE BUILDING
AND PROBABLY SET IN THROUGH AT LEAST LATE MORNING /A SCENARIO THAT
THE HRRR SUPPORTS/. WE WILL HAVE PATCHY FOG IN THE FORECAST ACROSS
SOUTHEASTERN MT THROUGH 15 UTC AS WELL. MEANWHILE...DRAINAGE WINDS
HAVE ACTUALLY TAKEN HOLD OVER SOUTH CENTRAL MT...WHICH HAS LOWERED
DEWPOINTS AND LIKELY NEGATED ANY FOG THREAT THIS MORNING IN PLACES
LIKE BILLINGS.
TODAY...WE HAVE REALIGNED AFTERNOON POPS TO FOCUS ON SOUTH CENTRAL
MT AND NORTH CENTRAL WY WHERE TERRAIN CIRCULATIONS WILL LIKELY AID
CONVECTIVE DEVELOPMENT...WHILE REMOVING THEM AND GOING WITHOUT ANY
MENTION OF STORM CHANCES IN MOST OF SOUTHEASTERN MT. THE CHOICE TO
GO WITH A DRY AFTERNOON FORECAST IN SOUTHEASTERN MT WAS BASED ON A
LACK OF DISCERNIBLE SHORT WAVE IMPULSES EITHER UPSTREAM IN MORNING
MOISTURE CHANNEL IMAGES OR IN AFTERNOON MODEL SIMULATIONS. NOT ONE
OF THE HIGH-RESOLUTION...CONVECTION-ALLOWING MODELS USED IN THE 00
UTC SPC SSEO DEVELOPED STORMS IN SOUTHEASTERN MT...WHICH CERTAINLY
HELPED BUILD OUR CONFIDENCE IN A DRY FORECAST. MLCAPE OF 1000 J/KG
WILL BE PRESENT DURING PEAK HEATING THOUGH...SO WE WILL KEEP WATCH
OF NEAR-TERM TRENDS IN CASE CHANCES NEED TO BE ADDED BACK IN LATER
ON. MEANWHILE...OVER SOUTH CENTRAL MT AND NORTH CENTRAL WY...AFTER
SEEING HOW EASILY CONVECTION FORMED SAT IN THIS SYNOPTIC SITUATION
OUR CONFIDENCE IN STORM DEVELOPMENT HAS INCREASED. THE MODELS FROM
00 UTC ADD SUPPORT FOR THIS. GUSTY WINDS OR EVEN A MARGINAL SEVERE
STORM IS POSSIBLE /SIMILAR TO SAT/. MOREOVER...THE 21 UTC SREF HAS
NOTABLE PROBABILITIES FOR DRY THUNDERSTORMS...WHICH IS A VERY REAL
POSSIBILITY WHERE FORECAST SOUNDINGS HAVE PRECIPITABLE WATERS LESS
THAN ABOUT 0.80 INCHES /WEST OF BILLINGS TOWARD LIVINGSTON/. BASED
ON MID- AND UPPER-LEVEL WINDS...STORM MOTIONS COULD BE SLOW ENOUGH
TO ELEVATE WETTING RAIN CHANCES A BIT MORE THAN THEY COULD BE IN A
SITUATION LIKE THIS...SO A LARGE-SCALE /RED FLAG-WORTHY/ LIGHTNING
EVENT IS NOT EXPECTED AT THIS TIME.
TONIGHT...THE 00 UTC SPC SSEO AS WELL AS 500-HPA VORTICITY MAXIMUM
FIELDS FROM THE 00 UTC GFS /AND TO AN EXTENT THE ECMWF/ SUPPORT 30
TO 40 PERCENT STORM CHANCES THIS EVENING FROM HARLOWTON TOWARD BIG
TIMBER AND EAST TO BILLINGS. GUSTY WINDS...MARGINAL SEVERE RISK...
AND SOME DRY LIGHTNING POTENTIAL WILL CONTINUE WITH STORMS THROUGH
THE EVENING AS WELL. LOW POPS ARE SUPPORTED OVER THE WHOLE AREA AS
A WEAK 500-HPA SHORT WAVE MAY MOVE INTO SOUTHEASTERN MT OVERNIGHT.
MON...THE LARGE-SCALE PATTERN WILL REMAIN SIMILAR...BUT THERE HAVE
BEEN SOME INDICATIONS FOR BETTER FORCING NEAR A STATIONARY FRONTAL
BOUNDARY IN SOUTHEASTERN MT DURING THE AFTERNOON AND EVENING. THAT
COULD GENERATE ANOTHER MORE NOTABLE SEVERE RISK GIVEN 0-6-KM SHEAR
VECTORS OF 30 KT OR MORE. WE NEED TO HAVE AT LEAST LOW POPS ACROSS
THE REST OF THE AREA AGAIN TOO. SCHULTZ
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
NO SIGNIFICANT CHANGES WERE MAE IN THE EXTENDED FORECAST PERIODS
FOR THIS PACKAGE. A RIDGE OF HIGH PRESSURE WILL DOMINATE THE
EXTENDED TIME FRAME WITH ACTIVE CONVECTIVE WEATHER THROUGH ABOUT
MIDWEEK...WINDING DOWN TO A DRIER AND WARMER REGIME FOR THE LATTER
PART OF THE WORK WEEK. LONG RANGE PROGGS DO INDICATE A SIGNIFICANT
WEATHER SYSTEM CRASHING THE RIDGE NEXT SATURDAY/SATURDAY NIGHT.
THIS WILL NEED TO BE MONITORED FOR FIRE WEATHER CONCERNS. BT
&&
.AVIATION...
AREAS OF FOG ARE LIFTING FROM KMLS TO KBHK AND SOUTH...BUT LOW
CLOUDS MAY LINGER INTO AFTERNOON. SHOWERS AND THUNDERSTORMS ARE
EXPECTED ACROSS ALL ROUTES THIS AFTERNOON AND INTO THE
EVENING...BEGINNING OVER WESTERN TERMINALS. LOCAL IFR TO MVFR CAN
BE EXPECTED WITHIN STRONGER THUNDERSTORMS. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 086 062/088 059/086 060/087 060/091 062/093 062/091
3/T 32/T 22/T 22/T 20/U 00/U 01/U
LVM 088 054/089 052/088 052/088 050/091 051/095 051/090
3/T 32/T 22/T 22/T 21/U 10/U 01/U
HDN 088 060/091 058/089 058/088 059/092 059/095 059/093
2/T 32/T 32/T 22/T 20/U 00/U 00/U
MLS 085 063/088 061/087 061/087 061/091 063/094 064/093
2/T 23/T 32/T 23/T 31/U 00/U 01/U
4BQ 085 059/088 058/086 058/087 058/090 059/093 059/093
2/T 23/T 32/T 33/T 30/U 00/U 00/U
BHK 080 058/082 056/080 057/082 057/087 058/089 059/089
2/T 23/T 33/T 33/T 32/T 00/U 01/U
SHR 087 056/088 055/087 056/087 054/089 055/092 055/092
3/T 33/T 32/T 22/T 21/U 10/U 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
638 AM CDT SUN AUG 11 2013
.AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK.
MAIN AVN CONCERN IS TSRA DEVELOPING LATER THIS AFTN. A FRONTAL
BNDRY OVER THE DAKOTAS THIS MORNING IS EXPECTED TO SLOWLY DRIFT
SWD AND PUSH INTO ERN NEBR LATE THIS AFTN. EXPECT STORMS WILL
DEVELOP ROUGHLY BTWN KSUX AND KGRI THEN ADVANCE SWD INTO THE
EARLY EVENING. ENVIRONMENTAL CONDITIONS WILL BE FAVORABLE FOR A
FEW SVR TSRA...AND AT THIS POINT PROBABLY MORE LIKELY TO BE AN
ISSUE AT KOMA AND KLNK. HOWEVER...WENT CONSERVATIVE WITH THE 12Z
TAF GROUPS AND DID NOT INCLUDE MENTION OF SVR STORMS IN THE TEMPO
GROUPS. OTHERWISE VFR THE REST OF THE FCST PD.
DEE
&&
.PREV DISCUSSION... /ISSUED 246 AM CDT SUN AUG 11 2013/
DISCUSSION...
PRECIPITATION CHANCES THROUGH MONDAY NIGHT PRIMARY FORECAST FOCUS
AS A WEAK FRONT SAGS ACROSS THE FA LATE TODAY INTO MONDAY.
EARLY MORNING SATELLITE/RADAR SHOWED A VORT MAX/TROUGH MOVG SE
ACROSS NWRN MN WITH SEVERAL CONVECTIVE CLUSTERS TO THE SW ON NOSE
OF LOW LEVEL JET/WARM ADVECTION OVR SD INTO NW IA. ALTHOUGH
VARIOUS SHORT TERM MODELS LIKE HOP WRF/RAP KEPT PRECIP MOSTLY NE
OF FA THIS AM ...4KM WRF AND HRRR DID TRY TO DEVELOP SOME OVER NRN
ZONES THIS MORNING. SO SOME SMALL POPS WILL BE MAINTAINED WITH
LAST MINUTE ADJUSTMENTS POSSIBLE BASED ON TRENDS BEFORE ISSUANCE.
OTHERWISE WITH BOUNDARY FORECAST TO SLOWLY SAG INTO NRN ZONES THIS
AFTN...HEATING SHOULD HELP REGENERATE CONVECTION LATER THIS
AFTERNOON...ALTHOUGH 4KM WHICH DEVELOPED IT MOSTLY S OF HIGHWAY 30
APPEARED TOO FAR S. COVERAGE THIS AFTERNOON AND EVOLUTION TONIGHT
IN DOUBT AS H5-H7 QG FORCING WAS NEGLIGIBLE WITH DIFFERENTIAL
HEATING ACROSS BOUNDARY THIS AFTN THEN SYSTEM MOTION FOR INFLOW
WOULD BE PRIMARY DRIVERS AS LOW LEVEL JET WEAKENS FAIRLY
SUBSTANTIALLY THROUGH TONIGHT. THUS KEPT POPS IN CHC CATEGORY FOR
NOW FOR LATE AFTN THROUGH EARLY TONIGHT. WITH THIS LACK OF LOW
LEVEL JET TONIGHT CONFIDENCE NOT VERY HIGH ON HOW MUCH COVERAGE
WILL EXIST AFTER 06Z OVER FA SO GENERALLY TRENDED POPS DOWN AFTER
THAT TIME. WITH MODEL AGREEMENT IN H85 THERMAL RIDGE POKING UP
TOWARD WCNTRL ZONES THIS AFTN BOOSTED HIGHS A BIT...WHICH WERE
STILL BELOW WARMER NAM WHICH ONE OF THESE DAYS MAY ACTUALLY TURN
OUT BETTER IF SWRLY SFC WINDS CAN BE MAINTAINED LONG ENOUGH.
IF CONVECTION TONIGHT PUSHES EFFECTIVE BOUNDARY SOUTH OF FA BY
MONDAY AFTN FURTHER CONVECTIVE DEVELOPMENT COULD BE LIMITED OVER
OUR AREA AND TRENDS WILL NEED MONITORING. HOWEVER...FOR NOW LEFT
IN CHC POPS S WITH SLIGHTS N THROUGH NORFOLK OR SO AS BOUNDARY
PUSH WAS MODEST AT BEST. ALTHOUGH H85 TEMPS DON/T COOL SIGNIFICANTLY
YET ON MONDAY...TEMPERATURES SHOULD BE SOMEWHAT COOLER MOST
AREAS...ESPECIALLY IF DEBRIS CLOUDS CAN BE MAINTAINED. SOME POPS
WERE KEPT THEN MONDAY NIGHT SW 2/3RDS OR SO IN CASE ANY UPSTREAM
CONVECTION WOULD HOLD TOGETHER...ALTHOUGH MUST SAY NOT REALLY SOLD
ON THAT IDEA.
IN FACT...EVEN THOUGH SOME SMALL POPS WERE ALSO MAINTAINED TO INTO
MIDWEEK BEFORE SPREADING E TOWARD FRIDAY...APPEARS BULK OF ANY
ACTIVITY COULD REMAIN TO OUR WEST THROUGH LATE WEEK...ESPECIALLY
PER 00Z ECMWF. THAT MODEL HAS REMAINED FAIRLY CONSISTENT IN THAT
REGARD. PLEASANT TEMPERATURES LOOK IN STORE FOR FORECAST AREA
MUCH OF NEXT WEEK BEFORE MODERATING LATE AS NORTHWESTERLY FLOW
SENDS CANADIAN HIGH PRESSURE DOWN MISSISSIPPI VALLEY. THIS HAS
BEEN ONE OF OUR SAVING GRACES THIS SUMMER AS SIGNIFICANTS RAINS
HAVE BEEN SPOTTY AND MANY AREAS ARE RUNNING MODERATE PRECIP
DEFICITS SINCE JUNE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
927 AM MDT SUN AUG 11 2013
.UPDATE...
UPDATED MORNING PRECIPITATION CHANCES AND SKY COVER FOR NORTH-CENTRAL
AND WESTERN AREAS. RAIN COOLED/STABLE ATMOSPHERE IN PLACE THIS MORNING
OVER THESE AREAS SO NOT EXPECTING MUCH IN THE WAY OF CLOUDS AND/OR
SHOWERS. ALSO TRENDED DOWN POPS FOR THE RG VALLEY AND SAN JUAN RIVER
VALLEY FOR THIS AFTERNOON WITH MOST ACTIVITY HOLDING OFF UNTIL EARLY
EVENING AFTER SFC HEATING WORKS AWAY AT SUBSIDENCE INVERSION BEHIND
DEPARTING WAVE/MCV.
33
&&
.PREV DISCUSSION...538 AM MDT SUN AUG 11 2013...
.AVIATION...
12Z TAF CYCLE
WIDESPREAD SHOWERS AND A FEW TSRA CONTINUE SOUTH OF AN ABQ TO TCC
LINE. THIS ACTIVITY WILL CONTINUE INTO THE MID MORNING HOURS. LOW
VSBYS WILL BE POSSIBLE WITH THE HEAVIER SHOWERS...MAINLY AROUND
KCVS AND KCVN. CONFIDENCE IS NOT HAS HIGH FOR IFR CIGS NEAR ROW
THIS MORNING AS MID LEVEL CLOUD COVER HAS LINGERED OVER THE AREA.
OTHERWISE...THIS AFTERNOONS CONVECTION SHOULD START A BIT LATER
TODAY. STORMS WILL TEND TO FAVOR THE HIGH TERRAIN INITIALLY BEFORE
MOVING EAST OVER THE LOWER ELEVATIONS. OVERALL...STORMS SHOULD
NOT BE AS WIDESPREAD AS YDAY. LOCALLY HEAVY RAIN AND SMALL HAIL
WILL AGAIN BE A CONCERN WITH THE STRONGER STORMS.
34
.PREV DISCUSSION...330 AM MDT SUN AUG 11 2013...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
538 AM MDT SUN AUG 11 2013
.AVIATION...
12Z TAF CYCLE
WIDESPREAD SHOWERS AND A FEW TSRA CONTINUE SOUTH OF AN ABQ TO TCC
LINE. THIS ACTIVITY WILL CONTINUE INTO THE MID MORNING HOURS. LOW
VSBYS WILL BE POSSIBLE WITH THE HEAVIER SHOWERS...MAINLY AROUND
KCVS AND KCVN. CONFIDENCE IS NOT HAS HIGH FOR IFR CIGS NEAR ROW
THIS MORNING AS MID LEVEL CLOUD COVER HAS LINGERED OVER THE AREA.
OTHERWISE...THIS AFTERNOONS CONVECTION SHOULD START A BIT LATER
TODAY. STORMS WILL TEND TO FAVOR THE HIGH TERRAIN INITIALLY BEFORE
MOVING EAST OVER THE LOWER ELEVATIONS. OVERALL...STORMS SHOULD
NOT BE AS WIDESPREAD AS YDAY. LOCALLY HEAVY RAIN AND SMALL HAIL
WILL AGAIN BE A CONCERN WITH THE STRONGER STORMS.
34
&&
.PREV DISCUSSION...330 AM MDT SUN AUG 11 2013...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
949 AM EDT SUN AUG 11 2013
.SYNOPSIS...
A LARGE HIGH PRESSURE SYSTEM WILL REMAIN IN CONTROL OF THE WEATHER
PATTERN TODAY...ALLOWING FOR ONE MORE COMFORTABLE AND RAIN FREE
DAY ACROSS OUR REGION. HIGH TEMPERATURES WILL WARM INTO THE LOWER
TO MIDDLE 70S ACROSS MUCH OF THE AREA...WITH A FEW LOW 80S POSSIBLE
ACROSS THE LOWER WYOMING VALLEY. BY MONDAY...RAIN CHANCES WILL
INCREASE DURING THE LATE AFTERNOON AS A WEAK AREA OF LOW PRESSURE
BEGINS MOVING NORTH ALONG THE MID-ATLANTIC COAST. BY MONDAY NIGHT
AND TUESDAY...EXPECT RAIN CHANCES TO INCREASE AS A STRONG COLD
FRONT MOVES THROUGH THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
945 AM UPDATE... MORE IN THE WAY OF CLDNS...ALG WITH ISOLD
-SHRA/SPRINKLES WERE ADDED TO THE FCST TDY FOR OUR FAR SRN ZNS.
OTHWS...NO SIG CHGS ATTM.
SAT/RADAR IMAGERY SHOW A CLOUD BAND (GENERALLY 4-7 K FT AGL) MOVG
ACRS PA LATE THIS MRNG...ALG WITH POTENTIALLY A FEW SPRINKLES. A
CLOSER INSPECTION OF THE THERMAL/MOISTURE FIELDS SHOW SOME 850 MB
FGEN THIS RGN...OWING TO A NARROW RGN OF CONVERGENT FLOW...AND
ASSOCD MOIST CONDS/HIGHER DEW PTS. THE LATEST HRRR RUNS SEEM TO
PICK UP ON THIS SCENARIO...AND SHOW SOME WEAK RETURNS MOVG ACRS
PTNS OF NE PA THROUGH MID TO LATE AFTN. ALTHOUGH WE CERTAINLY
DON`T EXPECT MUCH PCPN OUT OF THIS...WE FELT IT PRUDENT TO THROW
IN ISOLD SHWRS/SPRINKLES...AND OBVIOUSLY INSERT ADDTNL CLOUD
COVER OVER THE NEAR-TERM.
DUE TO THE SHALLOW NATURE OF THE AFOREMENTIONED AREA OF
MOISTURE...WE THINK IT COULD MIX OUT TO SOME DEGREE DURG THE
AFTN. THUS...WE`RE ONLY CARRYING ISOLD/SCHC POPS TIL 18-21Z.
ALSO...WE THINK SOME BREAKS OF SUNSHINE ARE LIKELY TO DVLP THIS
AFTN OVER SRN PTNS OF THE FA...AND GIVEN THIS...WE DIDN`T DEVIATE
MUCH FROM OUR EARLIER HIGH TEMP FCST (GENERALLY 75-80 DEGS).
FARTHER N ACRS CNY...LIFE IS GOOD...WITH A DRY AMS/SINKING MOTION
REGIME IN PLACE. ONLY SOME SPOTTY FAIR WX CU IS ANTICIPATED...WITH
A GENERALLY SUNNY AFTN ON TAP.
PREV DISC... 08Z MSAS SURFACE ANALYSIS SHOWING A LARGE AREA OF
HIGH PRESSURE EXTENDING ACROSS MUCH OF THE GREAT LAKES REGION THIS
MORNING...WITH TEMPS LARGELY HOVERING IN THE LWR 50S. 11-3.9U
SATELLITE IMAGERY SHOWING A FEW PATCHES OF MID-LEVEL CLOUDS
STREAMING ACROSS THE REGION AS MOISTURE REMAINS TRAPPED BELOW A
FAIRLY STRONG SUBSIDENCE INVERSION WHICH IS READILY APPARENT ON
THE 00Z BUF RAOB. HEADING INTO TODAY...THESE CLOUDS WILL LIKELY
DISSIPATE AS DAYTIME HEATING COMMENCES BEFORE SOME SCATTERED FLAT
CU DEVELOP BY LATE MORNING AND EARLY AFTERNOON.
WITH NO SENSIBLE WX EXPECTED TODAY...MAIN FCST ISSUE REMAINS
CENTERED ON DAYTIME TEMPS. 850 TEMPS ARE FORECAST TO RISE A DEGREE
OR TWO OVER YESTERDAY/S VALUES...HOWEVER LOW-LEVEL FLOW WILL
REMAIN FROM THE NORTHWEST THROUGH A GOOD CHUNK OF THE DAY.
CONSIDERING MOST LOCATIONS UP ACROSS THE LAKE PLAIN REMAINED A FEW
DEGREES BELOW MODEL GUIDANCE ON SATURDAY...HAVE ELECTED TO
MAINTAIN A SIMILAR TREND TODAY WITH LOW TO MID 70S EXPECTED UP
NORTH...WITH MID TO UPPER 70S ANTICIPATED FROM THE TWIN TIERS
SOUTH.
A SIMILAR NIGHT EXPECTED TONIGHT WITH HIGH PRESSURE REMAINING IN
CONTROL OF THE WX PATTERN. THE ONLY POTENTIAL FLY IN THE OINTMENT
WILL BE A WEAK SHORTWAVE MOVING EAST THROUGH CENTRAL PA OVERNIGHT
WITH THE GFS OFFERING SOME LIGHT SHWR ACTIVITY ACROSS SOUTHEASTERN
PA AS WEAK WARM AIR ADVECTION INTERACTS WITH A MARINE FRONT.
THERE IS SOME POTENTIAL THAT SOME SHWRS MAY TRY BUILDING UP
TOWARDS OUR NE PA ZONES HOWEVER DECIDED TO LEAVE THE FCST DRY
CONSIDERING HOW DRY THE ATMOSPHERE CURRENTLY IS. WILL ALLOW THE
DAY SHIFT TO TAKE ANOTHER LOOK BEFORE DECIDED WHETHER A MENTION
WILL BE NEEDED. OVERNIGHT LOWS WILL AGAIN FALL INTO THE LOWER TO
MIDDLE 50S WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED
ALOFT. THIS SHOULD ALLOW FOR GREAT VIEWING CONDITIONS OF THE
PERSEID`S METEOR SHOWER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
CLOUDS TO BE ON THE INCREASE THROUGH THE DAY ON MONDAY AS STRONG
SHORTWAVE TROUGH ROTATES SOUTHEAST FROM WESTERN ONTARIO INTO THE
NORTH-CENTRAL LAKES. AS THIS OCCURS...STRENGTHENING SFC LOW
PRESSURE WILL BEGIN TRACKING FROM NORTHERN MICHIGAN INTO SOUTH-
CENTRAL ONTARIO...WITH A COLD FRONT EXTENDING WELL SOUTH THROUGH
THE OHIO VLY. A RETURN OF SOUTHERLY WINDS IN ADVANCE OF BOTH
FEATURES WILL LEAD TO INCREASING MOISTURE ADVECTION THROUGH THE
DAY WITH FCST MODELS HIGHLIGHTING POSSIBLE SHOWERS/ISO STORMS
ACROSS THE WESTERN ZONES BY LATE AFTERNOON...WITH ANOTHER AREA OF
SHWRS POSSIBLE ACROSS FROM NORTHEAST PA NORTH INTO THE CATSKILLS
AS AFOREMENTIONED MARINE FRONT LIFTS NORTH TOWARDS THE REGION.
BOTH THE GFS AND NAM SHOW A SHORTWAVE MOVING ACROSS THE REGION
DURING THE AFTERNOON OFFERING A LITTLE SYNOPTIC SCALE FORCING FOR
POSSIBLE DEVELOPMENT. AS SUCH...HAVE INCREASED POPS INTO THE CHC
CATEGORY BEGINNING IN THE AFTERNOON FROM THE TWIN TIERS AND
WESTERN FINGER LAKES SOUTH...BEFORE RISING POPS FURTHER TO THE
NORTH BY THE END OF THE PERIOD. INSTABILITY LOOKS MEAGER AT BEST
ONCE AGAIN HOWEVER WITH A FEW HUNDRED JOULES POTENTIALLY
AVAILABLE...HAVE DECIDED TO OFFER AN ISOLATED THUNDER MENTION.
MAIN COLD FRONT TO SLIDE THROUGH THE AREA ON TUESDAY WITH ALL
INDICATIONS SUGGESTING THE COLD FRONT WILL BEGIN MOVING THROUGH
OUR AREA BETWEEN THE 12-15Z TIME FRAME. BEYOND THIS...FEATURE WILL
QUICKLY RACE TO THE SOUTHEAST AS MAIN EASTERN CANADIAN CLOSED LOW
RETREATS TOWARDS EASTERN QUEBEC AND TRAILING SHORTWAVE ENERGY
QUICKLY SETTLES SOUTH ACROSS OUR AREA. THUS EXPECT A GRADUAL
DECREASE IN SHWRS/ISO STORMS THROUGH THE EVENING WITH DRY BUT COOL
CONDITIONS THEN ANTICIPATED TUE NIGHT. FOR NOW...MODEL TRENDS
SUGGEST BEST INSTABILITY WILL BE EAST OF OUR REGION LENDING HOPE
THAT ANY ORGANIZED SEVERE WX WILL NOT IMPACT OUT AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
4 AM UPDATE...
MODELS CONTINUE TO SHOW A BROAD TROF ALOFT THROUGH THE EXTENDED
PERIOD WITH SFC HIGH PRESSURE IN THE VICINITY. A BEAUTIFUL STRETCH
OF WEATHER FOR LATE SUMMER WITH TEMPS GRADUALLY MODIFYING TO
SEASONAL LEVELS BY LATE IN THE PERIOD. CURRENT FORECAST IN GOOD
SHAPE JUST MINOR ADJUSTMENTS BASED ON LATEST WPC GUIDANCE.
130 PM UPDATE... FROPA WL OCCUR ON TUESDAY LEAVING THE AREA
HIGH AND DRY WITH 1020MB SFC HIGH PRESSURE BUILDING IN. ALL MED
RANGE MODELS ARE IN EXTREMELY GOOD AGREEMENT AT BOTH THE SFC AND
ALOFT. UL TROF WL PERSIST THRU THE PD WITH OCNL CLD CVR MVG THRU
BUT VRY LITTLE FRCG APPEARS PRESENT AT THIS TIME THRU THE END OF
THE WEEK. HIGH PRESSURE WL BUILD OFF THE EAST COAST ON SATURDAY
WITH THE RETURN OF WARMER TEMPS FOR THE WEEKEND. BY THE END OF THE
LONG TERM TEMPS WL CLIMB TO MORE SEASONAL VALUES.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
DENSE VALLEY FOG AT KELM WILL PERSIST UNTIL 13Z/14Z THEN LIFT.
IN GENERAL, VFR CONDITIONS WILL PERSIST THROUGH THIS TAF PERIOD
WITH FEW/SCT CU AROUND 5K FT TODAY THEN JUST SCATTERED CI OVERNIGHT.
ANOTHER VALLEY FOG EVENT IS EXPECTED TONIGHT WITH KELM DROPPING
INTO THE IFR CATEGORY AROUND 09Z.
LIGHT WINDS BECOMING NORTHWEST 5-10 KNOTS THEN LIGHT AGAIN THIS EVENING.
OUTLOOK...
MON...MAINLY VFR.
MON NGT/TUE...MVFR IN SHRA/TSRA.
WED...MAINLY VFR.
THU...VFR...IFR PSBL IN AM AT KELM FROM FG/BR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/MLJ
SHORT TERM...CMG
LONG TERM...PVN/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
746 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730AM UPDATE...MINOR CHANGES TO NEAR TERM FCST FOR THE EARLY
MORNING UPDATE. IR/VIS SATL SHOWS BAND OF MID LVL CLOUDS STREAKING
EWD ALONG THE I-80 CORRIDOR...WITH SOME ISOLD SPRINKLES /LKLY NOT
MEASURABLE PCPN/ SHOWING UP ON RADAR. CLEARING TO THE NORTH ALONG
THE PA/NY BORDER HAS LEAD TO RIVER/STREAM VALLEY FOG. SOME FOG
ALSO INDICATED VIA SATL ACRS THE SCENTRL MTNS WHERE SKIES ARE ALSO
M/CLR.
PREVIOUS DISCUSSION...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN
DURING THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING
MUCH QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH
SHOT OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS
TEMPERATURES AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS
TO TURN SW LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND
APPROACHES. QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA
AND PLENTY OF SUN.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MAIN CHANGE AT 12Z IS THE BFD OB...NOTAM ISSUED...ET
STAFF LOOKING INTO ISSUE...UNABLE TO DIAL INTO SITE.
DUJ HAD A SHOWER. AS WAS THE CASE YESTERDAY...SOME SHOWERS
ON THE RADAR. I WAS THINKING THAT ANY SHOWERS WOULD BE ALONG
THE MD LINE...NOT UP BY I-80. STILL EXPECT THESE TO BE AWAY
FROM OUR TAF SITES.
A LOT OF CLDS...SO TOOK FOG OUT OF THE 06Z PACKAGE...BUT
A LITTLE FOG HERE AND THERE...BEEN ADJUSTING THE FCST FOR
THIS.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS/STEINBUGL
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
658 AM EDT SUN AUG 11 2013
.SYNOPSIS...
LOOK FOR VARIABLE CLOUD COVER AND NEAR SEASONABLE TEMPERATURES
TODAY ACROSS CENTRAL PENNSYLVANIA. THERE ARE A COUPLE WEAK WEATHER
DISTURBANCES MOVING ACROSS THE AREA WHICH COULD BRING A FEW
ISOLATED SHOWERS OR THUNDERSHOWERS...HOWEVER THE MAJORITY OF THE
AREA WILL BE RAIN FREE. MONDAY WILL FEATURE SIMILAR WEATHER
BEFORE A STRONGER FRONTAL SYSTEM APPROACHES ON MONDAY NIGHT AND
TUESDAY WHEN THE REGION WILL SE A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS. BEHIND THIS FRONT WILL BE COOLER AND DRIER
CONDITIONS FOR THE MIDDLE AND END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK BOUNDARY SETTING UP ACROSS WESTERN PA WITH A FEW LIGHT
RETURNS ON RADAR. THIS AREA IS SLOWLY DRIFTING EAST TOWARDS THE
WESTERN CWA BOUNDARY. HRRR RUNS SUGGEST THIS COULD HOLD TOGETHER
SO MADE A SMALL ADJUSTMENT TO UP POPS THERE. OTHERWISE THE REST OF
THE FORECAST LOOKING ON TRACK WITH VARIABLE CLOUDS AND SOME PATCHY
FOG BY SUNRISE. SUNDAY WILL SEE ANOTHER LOW CHANCE OF SHOWERS OR
EVEN AN ISOLATED THUNDERSTORM BUT THE LARGE MAJORITY OF THE REGION
WILL BE RAIN FREE. TEMPERATURES LOOKING VERY CLOSE TO SEASONAL
NORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CWA WILL BE AHEAD OF APPROACHING FRONTAL SYSTEM WITH SIMILAR
WEATHER TO SUNDAY. POPS ARE GREATEST LATER MONDAY AND MON NIGHT AS
FRONTAL BOUNDARY MOVES CLOSER TO REGION.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
WESTERN RIDGE AND EAST COAST TROUGH WILL BE THE PREVAILING PATTERN
DURING THIS PERIOD. FRONTAL SYSTEM ON TUESDAY WILL BRING A CHANCE
OF SHOWERS AND THUNDERSTORMS TO THE AREA. GUIDANCE NOT SHOWING
MUCH QPF WITH THIS EVENT...AND THE BIGGEST IMPACT WILL BE A FRESH
SHOT OF DRIER AND COOLER AIR FOR THE MIDDLE OF THE WEEK AS
TEMPERATURES AGAIN DROP BELOW AVERAGE ON WED AND THU. FLOW BEGINS
TO TURN SW LATE IN THE PERIOD FOR SOME MODERATION AS THE WEEKEND
APPROACHES. QUITE DRY PW FROM WED ON WITH NO POPS ACROSS THE CWA
AND PLENTY OF SUN.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MAIN CHANGE AT 12Z IS THE BFD OB...NOTAM ISSUED...ET
STAFF LOOKING INTO ISSUE...UNABLE TO DIAL INTO SITE.
DUJ HAD A SHOWER. AS WAS THE CASE YESTERDAY...SOME SHOWERS
ON THE RADAR. I WAS THINKING THAT ANY SHOWERS WOULD BE ALONG
THE MD LINE...NOT UP BY I-80. STILL EXPECT THESE TO BE AWAY
FROM OUR TAF SITES.
A LOT OF CLDS...SO TOOK FOG OUT OF THE 06Z PACKAGE...BUT
A LITTLE FOG HERE AND THERE...BEEN ADJUSTING THE FCST FOR
THIS.
PATTERN IS ONE OF FAST MOVING SHORTWAVES JUST TO THE SOUTH
OF PA INTO MONDAY. AFTER THIS...AN ABNORMALLY STRONG UPPER
LVL SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BY
MID WEEK. SHOWERS AND STRONG STORMS LIKELY WITH THIS FRONT.
OUTLOOK...
MON...VFR. SLIGHT CHANCE FOR A SHOWER SOUTH.
TUE...MAINLY VFR...BUT MVFR POSS IN SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS
NEAR TERM...ROSS
SHORT TERM...ROSS
LONG TERM...ROSS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1004 AM CDT SUN AUG 11 2013
.UPDATE...
FRONTAL BOUNDARY JUST TO OUR NORTHWEST PROGGED TO SAG SOUTHEASTWARD
DURING THE DAY BEFORE RETREATING TONIGHT. EXPECT TO SEE SHOWERS
AND ISOLATED THUNDERSTORMS INCREASE IN NUMBER AS WE TO THROUGH THE
DAY ESPECIALLY ONCE HEATING CRANKS UP. NOT EXPECTING TO SEE MUCH
IN THE WAY OF ORGANIZATION OF ACTIVITY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 651 AM CDT SUN AUG 11 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL TIMING/AREAL SHWR/TSTMS COVERAGE AND IMPACTS...
IFR/MVFR FOG IMPACTS 11/12Z-11/13Z & 12/06Z-12/12Z. EXPECTING A GRADUAL
TREND FROM IFR-VFR CEILINGS TOWARD VFR BKN CU BY 11/17Z. WITH STATIONARY
FRONT EXPECTED TO DRIFT SLOWLY NWD THRU 12/12Z AND A CONTINUANCE OF ZONAL
FLOW ALOFT...STILL EXPECTING SCT SHWR/TSTM DEVELOPMENT...JUST VERY HARD TO
PINPOINT EXACT TIMING/AREAL COVERAGE...VCSH WITH VCTS REMARKS DIURNALLY BASED.
EXPECTING SOME DECREASE IN SHWR/TSTM ACTIVITY AFTER 12/06Z-12/08Z WITH
BREAKS IN CEILINGS ALLOWING FOR MVFR FOG FORMATION.
PREV DISCUSSION.../ISSUED 329 AM CDT SUN AUG 11 2013/
WEAK STATIONARY FRONTAL BOUNDARY IS POSITIONED JUST NW OF THE MID
STATE THIS MORNING. IT NOW APPEARS THAT THIS FEATURE WILL MOVE
LITTLE OVER THE NEXT 24-48 HRS. OTW..CURRENT RADAR SHOWING SOME
SCT CONVECTION ACROSS FAR NORTHERN PORTIONS OF THE MID STATE.
WESTERLIES ALOFT ARE STILL IN PLACE AS THE W-E UPPER RIDGE REMAIN
SUPPRESSED TO OUR SOUTH.
LATEST HRRR SUPPORTING LESS IN THE WAY OF CONVECTION TODAY AND
TONIGHT. THIS IS FURTHER ENFORCED BY DRIER MOISTURE DEPTH LEVELS AS
COMPARED TO PREVIOUS DAYS. STILL THOUGH...PLENTY OF HUMIDITY TO
WORK WITH AND CANNOT RULES OUT LOW POPS FOR TODAY AND TONIGHT IN THE
20-40 PERCENT RANGE.
AS WE GO THROUGH MONDAY AND TUESDAY...MID LEVEL TEMPS WILL BEGIN TO
COOL AS AN UPCOMING TROUGHING PATTERN BEGINS TO EMERGE. AS OUR WINDS
ALOFT BECOME MORE NORTHERLY...A STRONGER COLD FRONT WILL BEGIN TO
PUSH SOUTHWARD AND FURTHER INCREASE PRECIP CHANCES. LOOKS AS THOUGH
THE FROPA WILL OCCUR SOMETIME LATE WEDNESDAY AS IT APPEARS TO SLOW
DOWN A BIT. WILL GO AHEAD AND INCLUDE INCREASING POPS WITH TIME WITH
LIKELY VALUES BY TUESDAY. TEMPERATURES WILL RUN A DEGREE OR TWO
ABOVE NORMAL. MOS NUMBERS LOOK REASONABLE.
IN THE EXT FCST...SHOWER AND TSTM CHANCES WILL REMAIN RATHER HIGH ON
WEDNESDAY AS THE FRONT REMAINS IN CLOSE PROXIMITY. SOME DRIER AIR
WILL WORK IN THU-SAT BUT AFTERNOON ELEVATED CAPE VALUES WILL
RETURN BY THE WEEKEND. THEREFORE...LOW 20-30 POPS WILL RETURN BY
THE TAIL END OF THE EXTENDED.
OTW...STILL LOOKING AT A COOLING TREND FOR THE EXT WITH LOWS MID TO
UPPER 60S...HIGHS MID 80S...COOLER PLATEAU.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
925 AM EDT SUN AUG 11 2013
.DISCUSSION...SHOWERS AND STORMS ALREADY ON THE INCREASE THIS
MORNING AND TRAINING ALONG THE FRONTAL BOUNDARY...ALONG AND JUST
NORTH OF TN/KY STATELINE EAST INTO SW VA. COVERAGE HAS INCREASED
ENOUGH...THAT I WILL LIKELY UPDATE GRIDS AND PRODUCTS BY MID MORNING
RATHER THAN NOON TODAY. LATEST RUC MODEL RUN SPREADS CONVECTION OVER
THE BULK OF THE FORECAST AREA THROUGH THE AFTERNOON...SO PLAN TO
KEEP OR EVEN EXPAND LIKELY POPS FOR TODAY.
LOCALLY HEAVY RAINS THE MAIN THREAT AS HAS BEEN FOR THE PAST FEW
DAYS. HOWEVER...24 HOUR RAINFALL PRODUCT FROM MORRISTOWN AND HYTOP
RADARS SHOWED FEWER POCKETS OF VERY HEAVY RAINS OVER THE PAST 24
HOURS.
FOG IS DISSIPATING AND LOW CLOUD DECK LIFTING AT THIS TIME...SO WILL
ALSO REMOVE FOG AND MORNING WORDING IN THE UPDATE. MOS MAX TEMPS FOR
TODAY WERE UNDERCUT AND THIS SHOULD WORK OUT WELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 89 72 88 72 83 / 60 30 50 50 70
KNOXVILLE MCGHEE TYSON AIRPORT, TN 89 70 86 71 81 / 60 20 40 50 60
OAK RIDGE, TN 89 69 86 70 82 / 60 20 40 50 70
TRI CITIES AIRPORT, TN 88 65 83 66 78 / 50 20 40 50 60
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
651 AM CDT SUN AUG 11 2013
.UPDATE...FOR 12Z AVIATION DISCUSSION.
&&
.AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL TIMING/AREAL SHWR/TSTMS COVERAGE AND IMPACTS...
IFR/MVFR FOG IMPACTS 11/12Z-11/13Z & 12/06Z-12/12Z. EXPECTING A GRADUAL
TREND FROM IFR-VFR CEILINGS TOWARD VFR BKN CU BY 11/17Z. WITH STATIONARY
FRONT EXPECTED TO DRIFT SLOWLY NWD THRU 12/12Z AND A CONTINUANCE OF ZONAL
FLOW ALOFT...STILL EXPECTING SCT SHWR/TSTM DEVELOPMENT...JUST VERY HARD TO
PINPOINT EXACT TIMING/AREAL COVERAGE...VCSH WITH VCTS REMARKS DIURNALLY BASED.
EXPECTING SOME DECREASE IN SHWR/TSTM ACTIVITY AFTER 12/06Z-12/08Z WITH
BREAKS IN CEILINGS ALLOWING FOR MVFR FOG FORMATION.
&&
.PREV DISCUSSION.../ISSUED 329 AM CDT SUN AUG 11 2013/
WEAK STATIONARY FRONTAL BOUNDARY IS POSITIONED JUST NW OF THE MID
STATE THIS MORNING. IT NOW APPEARS THAT THIS FEATURE WILL MOVE
LITTLE OVER THE NEXT 24-48 HRS. OTW..CURRENT RADAR SHOWING SOME
SCT CONVECTION ACROSS FAR NORTHERN PORTIONS OF THE MID STATE.
WESTERLIES ALOFT ARE STILL IN PLACE AS THE W-E UPPER RIDGE REMAIN
SUPPRESSED TO OUR SOUTH.
LATEST HRRR SUPPORTING LESS IN THE WAY OF CONVECTION TODAY AND
TONIGHT. THIS IS FURTHER ENFORCED BY DRIER MOISTURE DEPTH LEVELS AS
COMPARED TO PREVIOUS DAYS. STILL THOUGH...PLENTY OF HUMIDITY TO
WORK WITH AND CANNOT RULES OUT LOW POPS FOR TODAY AND TONIGHT IN THE
20-40 PERCENT RANGE.
AS WE GO THROUGH MONDAY AND TUESDAY...MID LEVEL TEMPS WILL BEGIN TO
COOL AS AN UPCOMING TROUGHING PATTERN BEGINS TO EMERGE. AS OUR WINDS
ALOFT BECOME MORE NORTHERLY...A STRONGER COLD FRONT WILL BEGIN TO
PUSH SOUTHWARD AND FURTHER INCREASE PRECIP CHANCES. LOOKS AS THOUGH
THE FROPA WILL OCCUR SOMETIME LATE WEDNESDAY AS IT APPEARS TO SLOW
DOWN A BIT. WILL GO AHEAD AND INCLUDE INCREASING POPS WITH TIME WITH
LIKELY VALUES BY TUESDAY. TEMPERATURES WILL RUN A DEGREE OR TWO
ABOVE NORMAL. MOS NUMBERS LOOK REASONABLE.
IN THE EXT FCST...SHOWER AND TSTM CHANCES WILL REMAIN RATHER HIGH ON
WEDNESDAY AS THE FRONT REMAINS IN CLOSE PROXIMITY. SOME DRIER AIR
WILL WORK IN THU-SAT BUT AFTERNOON ELEVATED CAPE VALUES WILL
RETURN BY THE WEEKEND. THEREFORE...LOW 20-30 POPS WILL RETURN BY
THE TAIL END OF THE EXTENDED.
OTW...STILL LOOKING AT A COOLING TREND FOR THE EXT WITH LOWS MID TO
UPPER 60S...HIGHS MID 80S...COOLER PLATEAU.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1042 AM CDT SUN AUG 11 2013
.DISCUSSION...UPDATED HOURLY GRIDS TO REFLECT TRENDS. THE BULK OF
THE SHOWER AND THUNDER ACTIVITY REMAINS WELL SOUTH OF THE CWA...AS
THE UPPER LOW IS POSITIONED FARTHER SOUTH THAN EXPECTED. HOWEVER
MODELS CONTINUE TO SHIFT THE LOW AND THE ASSOCIATED SURFACE
COASTAL TROUGH WEST ACROSS THE REGION. WITH AN UNSTABLE AIRMASS
AND LITTLE TO NO CAPPING...WILL CONTINUE TO EXPECT COVERAGE TO
FILL IN THROUGH THE EARLY AFTERNOON...WITH BETTER DEVELOPMENT OVER
LAND ALONG THE SEA BREEZE. ACTIVITY SHOULD DIMINISH THIS LATE
AFTERNOON/EARLY EVENING WITH THE LOSS OF HEATING.
&&
.PREV DISCUSSION... /ISSUED 630 AM CDT SUN AUG 11 2013/
DISCUSSION...SEE 12Z AVIATION DISCUSSION.
AVIATION...PRETTY MUCH NO CHANGE IN THE TIMING OF THE CONVECTION
AS THAT STILL LOOKS GOOD. ANOTHER ROUND OF SCATTERED CONVECTION
EXPECTED TODAY...AND PRETTY MUCH KEPT TIMING OF THE TEMPOS WITH
VCTS STARTING ABOUT AN HOUR BEFORE TEMPO AND ENDING ABOUT ONE HOUR
AFTER TEMPO ENDS. SOME MORNING MVFR BR AND HAVE INCLUDED IN KALI
AND KVCT BUT CANNOT RULE OUT IT OCCURRING IN KCRP AND KLRD.
OTHERWISE...VFR CONDITIONS OUTSIDE OF CONVECTION. WINDS AGAIN
START OFF LIGHT AND VARIABLE THIS MORNING...GRADUALLY VEERING
DURING THE DAY/AFTERNOON AND BECOMING SOUTHEAST GENERALLY LESS
THAN 11 KNOTS (OUTSIDE OF THUNDER). WINDS BECOME VERY LIGHT AOB
06Z...AND COULD HAVE FOG AGAIN AT KVCT AND KALI BEFORE END OF
TERMINAL FORECAST. HELD OFF AT KALI BUT PUT 5SM BR AT KVCT ABOUT
09Z. NO RAINFALL FORECAST FOR THE OVERNIGHT PERIOD.
PREV DISCUSSION... /ISSUED 346 AM CDT SUN AUG 11 2013/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 30 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 30 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
630 AM CDT SUN AUG 11 2013
.DISCUSSION...SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...PRETTY MUCH NO CHANGE IN THE TIMING OF THE CONVECTION
AS THAT STILL LOOKS GOOD. ANOTHER ROUND OF SCATTERED CONVECTION
EXPECTED TODAY...AND PRETTY MUCH KEPT TIMING OF THE TEMPOS WITH
VCTS STARTING ABOUT AN HOUR BEFORE TEMPO AND ENDING ABOUT ONE HOUR
AFTER TEMPO ENDS. SOME MORNING MVFR BR AND HAVE INCLUDED IN KALI
AND KVCT BUT CANNOT RULE OUT IT OCCURRING IN KCRP AND KLRD.
OTHERWISE...VFR CONDITIONS OUTSIDE OF CONVECTION. WINDS AGAIN
START OFF LIGHT AND VARIABLE THIS MORNING...GRADUALLY VEERING
DURING THE DAY/AFTERNOON AND BECOMING SOUTHEAST GENERALLY LESS
THAN 11 KNOTS (OUTSIDE OF THUNDER). WINDS BECOME VERY LIGHT AOB
06Z...AND COULD HAVE FOG AGAIN AT KVCT AND KALI BEFORE END OF
TERMINAL FORECAST. HELD OFF AT KALI BUT PUT 5SM BR AT KVCT ABOUT
09Z. NO RAINFALL FORECAST FOR THE OVERNIGHT PERIOD.
&&
.PREV DISCUSSION... /ISSUED 346 AM CDT SUN AUG 11 2013/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 40 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 40 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
136 PM PDT SUN AUG 11 2013
.DISCUSSION...AS OF 1:36 PM PDT SUNDAY...AN UPPER TROUGH OFF THE
CA COASTLINE CONTINUED TO DOMINATE THE WEATHER PATTERN...WITH
MODERATE ONSHORE FLOW AND ABUNDANT STRATUS OFFSHORE. IN FACT...THE
ONSHORE GRADIENT ACTUALLY STRENGTHENED THIS AFTERNOON COMPARED TO
YESTERDAY AFTERNOON...RESULTING IN COOLER TEMPERATURES ALONG THE
COAST. AT THE SAME TIME...A VERY SUBTLE WARMING TREND OCCURRED
INLAND...WITH TEMPERATURES RANGING FROM THE 70S TO MID 80S
INLAND. THESE TEMPERATURES ARE STILL ABOUT 5 TO 10 DEGREES BELOW
NORMAL FOR THE MIDDLE OF AUGUST.
ANOTHER TYPICAL EVENING IS IN STORE FOR THE REGION...AS THE MARINE
LAYER REMAINS AROUND 1500 FEET...WITH PATCHY COASTAL DRIZZLE
POSSIBLE AGAIN LATE TONIGHT/EARLY MONDAY MORNING. BOTH THE NAM AND
HRRR INDICATE ISOLATED AREAS OF 0.01" TO 0.02" UP AND DOWN THE
COASTLINE. THE NAM AND HRRR CONTINUE TO VERIFY WELL WITH REGARDS
TO DRIZZLE...SO IT WAS ADDED TO THE ENTIRE COASTLINE.
A WARMING TREND WILL CONTINUE MONDAY INTO THE MIDDLE OF NEXT WEEK
AS AN UPPER LEVEL RIDGE SETS UP OVER THE FOUR CORNERS REGION WITH
HIGH PRESSURE NUDGING WEST INTO CA. 850 MB TEMPERATURES ARE
FORECAST TO RISE FROM THE 17 DEGREES C RANGE MONDAY AFTERNOON...TO
BETWEEN 21 AND 23 DEGREES C BY WEDNESDAY AFTERNOON. THIS WILL
RESULT IN DAYTIME HIGH TEMPERATURES CLIMBING INTO THE 80S TO MID
90S INLAND...NEAR NORMAL FOR THE MIDDLE OF AUGUST. TEMPERATURES
ALONG THE COAST WILL REMAIN MILD...AS COASTAL LOW CLOUDS WILL BE
PRESENT EACH NIGHT INTO THE MORNING HOURS...WITH TEMPERATURES
MAINLY IN THE 60S.
BY THURSDAY...A SIGNIFICANT UPPER LEVEL LOW WILL MOVE EAST TOWARD
THE PAC NW COASTLINE...WITH AN UPPER TROUGH DIGGING SOUTH AND
IMPACTING THE CA COAST. THIS WILL RESULT IN A DEEPENING MARINE
LAYER...STRONGER ONSHORE FLOW...AND A COOLING TREND INTO AT LEAST
FRIDAY.
OTHERWISE...NO MAJOR CHANGES TO THE FORECAST...WITH A PERSISTENT
DRY WEATHER PATTERN AND SUBTLE VARIATIONS WITH REGARDS TO THE
MARINE LAYER AND TEMPERATURE FORECAST.
&&
.AVIATION...AS OF 10:40 AM PDT SUNDAY...MARINE LAYER DEPTH
CONTINUES AROUND 1500 FEET AND MOST TERMINALS ARE STILL AFFECTED
BY LOW STRATUS CEILINGS. EXPECT CLEARING WITHIN THE NEXT HOUR OR
TWO. AFTERNOON SEABREEZE WINDS EXPECTED ONCE AGAIN.
VICINITY OF KSFO...MVFR CIGS UNTIL 19-20Z. WEST WIND GUSTS TO 20-22
KNOTS BEGINNING 21Z TODAY. EARLY CIG RETURN TONIGHT BY 03Z.
KSFO BRIDGE APPROACH...MVFR CIGS CLEARING BEFORE SFO. SOUTH PART
OF BAY IS ALREADY CLEAR...EXPECT VFR BY 19Z.
MONTEREY BAY AREA TERMINALS...IFR CIGS TIL 20Z. EARLY RETURN OF
LOW CLOUDS BY 02Z.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: RILEY
AVIATION/MARINE: SIMS
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
518 PM CDT SUN AUG 11 2013
.DISCUSSION...
310 PM CDT
MAIN FORECAST CONCERNS FOCUS ON SHOWER/THUNDERSTORM POTENTIAL
THROUGH THE FIRST 24-36 HOURS OF THE PACKAGE...WITH THE APPROACH AND
PASSAGE OF SLOW MOVING COLD FRONT AND WEAK FRONTAL WAVE TONIGHT
THROUGH MONDAY. SURFACE HIGH PRESSURE WILL THEN SPREAD ACROSS THE
REGION MID-LATE WEEK...MAKING FOR A RELATIVELY QUIET PERIOD OF
AUGUST WEATHER...WITH TEMPERATURES AVERAGING COOLER THAN NORMAL.
THE MAIN FEATURES ON THE LOCAL WEATHER MAP THIS AFTERNOON CONSIST OF
AN AREA OF HIGH PRESSURE OVER CENTRAL ILLINOIS...WHICH CONTINUES TO
WEAKEN AND DRIFT SOUTHEAST OF THE LOCAL CWA. OF MORE INTEREST IS A
WEST-EAST SURFACE FRONTAL BOUNDARY...WHICH STRETCHES FROM THE HIGH
PLAINS OF EASTERN WYOMING...ACROSS NEBRASKA AND NORTHERN IOWA INTO
FAR NORTHWEST ILLINOIS PER 19Z ANALYSIS. WEAKENING AREAS OF
PRECIPITATION HAVE CONTINUED TO WORK EAST ACROSS SOUTHERN
MN/NORTHERN IA AND SOUTHERN WI DURING THE DAY...IN RESPONSE TO WEAK
BUT PERSISTENT WEST-SOUTHWEST LOW LEVEL FLOW INDUCED BY SHORT WAVE
PROPAGATING ACROSS THE UPPER MISSISSIPPI VALLEY...AND ASSOCIATED
WARM/MOIST ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE. WHILE
PRECIP IN THE WFO LOT CWA HAS BEEN LIMITED TO MAINLY A FEW SPRINKLES
ALONG THE IL/WI BORDER...SPC RAP MESOANALYSIS AND RAP/WRF FORECAST
SOUNDINGS CONTINUE TO DEPICT SOME WEAK INSTABILITY DEVELOPING OVER
NORTHWEST/NORTH CENTRAL IL NEAR THE SURFACE FRONT DURING THE LATE
AFTERNOON HOURS. 250-500 J/KG MUCAPE ADMITTEDLY WEAK...THOUGH
PRESENCE OF PERSISTENT WEAK CONVERGENCE/ASCENT ALONG THE BAROCLINIC
BOUNDARY DOES PRESENT SOME POTENTIAL FOR ADDITIONAL SHRA/ISOLATED
TSRA DEVELOPMENT...WITH SOME INCREASE IN CU DEVELOPMENT NOTED IN
RECENT GOES VIS IMAGERY. HAVE MAINTAINED AN ISOLATES SHRA/TSRA
MENTION AFTER 4-5 PM ACROSS PARTS OF NORTH CENTRAL ILLINOIS ROUGHLY
NORTH OF THE ROCK AND WEST OF THE FOX RIVERS.
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS THEN APPEARS TO INCREASE
FROM MID/LATE-EVENING INTO THE OVERNIGHT HOURS FROM NORTHEAST IOWA
INTO SOUTHERN WISCONSIN...AND ADJACENT PORTIONS OF NORTHERN
ILLINOIS. THIS INCREASE IS IN RESPONSE TO WEAK LARGE SCALE HEIGHT
FALLS INDICATIVE OF ASCENT WITH ADDITIONAL SHORT WAVE ENERGY
APPROACHING FROM UPSTREAM...AND INCREASING MOISTURE TRANSPORT ALONG
LOW LEVEL BAROCLINIC ZONE WITH 925-850MB WEST-SOUTHWEST 20-25 KT
FLOW AS INDICATED BY COMPLEMENTARY RAP/WRF-NAM PROGS. UPPER LEVEL
DIVERGENCE IN RIGHT ENTRANCE REGION TO UPPER LEVEL JET STREAK MAY
ALSO AID IN DEVELOPMENT FROM NORTHEAST IA INTO SOUTHWEST WI EARLIER
IN THE NIGHT...BEFORE IT TRANSLATES FARTHER EAST ACROSS MICHIGAN
LATE. WEAK SURFACE WAVE ALONG FRONT CURRENTLY OVER NORTHEAST
NEBRASKA IS PROGGED TO MOVE ACROSS SOUTHERN WI IN THE PROCESS.
WITH THE LOW LEVEL JET GRADUALLY VEERING FROM WEST-SOUTHWEST TO WEST
THROUGH THE NIGHT...THIS SHOULD HELP FOCUS FOR PRECIP SHIFT FROM
NORTHEAST IA/SOUTHWEST WI EARLY...TO SOUTHWESTERN MICHIGAN BY
SUNRISE. ALL GUIDANCE POINTS TO A FAIRLY LIMITED PORTION OF NORTHERN
IL BEING AFFECTED...PRIMARILY NORTH OF THE INTERSTATE 88 CORRIDOR.
WHILE INSTABILITY IS NOT PARTICULARLY IMPRESSIVE...UPSTREAM PWAT
VALUES ARE ROUGHLY 1.25-1.50 INCHES AND WESTERLY LOW LEVEL FLOW
MAY SUPPORT SLOW EASTWARD TRANSLATION OF RESULTING CELLS. THIS COULD
PRODUCE SOME LOCALLY HEAVY RAINFALL IF TRAINING WERE TO OCCUR.
THE TRAILING COLD FRONT IT THEN PROGGED TO PUSH SLOWLY SOUTHEAST
ACROSS THE FORECAST AREA ON MONDAY...AS THE WEAK LOW PULLS AWAY
ACROSS LOWER MICHIGAN AND DEEPER FLOW OVER THE UPPER MIDWEST BECOMES
NORTHWESTERLY WITH DIGGING UPPER TROUGH. ADDITIONAL SCATTERED SHOWER
AND THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG/AHEAD OF THE FRONT...
WITH THE GREATEST POTENTIAL ACROSS THE SOUTHEAST HALF OF THE CWA
WHERE THE FRONT WILL BE DURING THE BETTER DIURNAL INSTABILITY.
INCREASE IN MID-LEVEL FLOW ACROSS THE REGION ON MONDAY WILL LIKELY
SUPPORT A GREATER CONDITIONAL MARGINAL SEVERE WIND/HAIL THREAT
ACROSS THE SOUTHEAST COUNTIES AND AREAS EAST BY AFTERNOON.
UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHEAST CONUS INTO MONDAY
NIGHT...WITH A SECONDARY PUSH OF COOLER DRIER AIR FROM THE NORTH
HELPING TO SHOVE THE COLD FRONT OUT OF THE CWA OVERNIGHT...AND COOL
HIGH PRESSURE BUILDING SOUTHEAST ACROSS THE AREA TUESDAY-WEDNESDAY.
WITH THE MAIN UPPER TROUGH AXIS REMAINING OFF TO THE EAST OF THE
AREA...AND UPPER RIDGE TO THE WEST ACROSS ROCKIES...A PERIOD OF
FAIRLY QUIET AND COOLER THAN AVERAGE WEATHER IS ANTICIPATED. LOW
LEVEL THERMAL GUIDANCE SUGGESTS AFTERNOON HIGHS IN THE MID-UPPER 70S
DURING THE MID-WEEK PERIOD...GRADUALLY MODERATING TO THE UPPER 70S
AND LOWER 80S LATE WEEK AND NEXT WEEKEND. SOME INDICATION IN THE
LONGER RANGE GUIDANCE THAT AN UPPER LOW WILL DEVELOP ACROSS THE
LOWER OHIO OR TENNESSEE VALLEYS LATE IN THE WEEKEND...WITH BOTH THE
ECMWF AND GFS RUNS SUGGESTING THE POTENTIAL TO WRAP A LITTLE
MOISTURE INTO THE AREA FROM THE SOUTHEAST. OTHERWISE...APPEARS
MAINLY DRY THROUGH THE PERIOD BEYOND TOMORROW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* E-W LINE OF SCATTERED SHOWERS...POSSIBLE ISOLATED THUNDER NEXT
FEW HOURS
* POTENTIAL FOR SOME VARIABILITY IN WINDS IN VICINITY OF SHOWERS
* MORE WIDESPREAD SHOWERS AND POSSIBLE THUNDER AFTER MIDNIGHT
ALLSOPP
//DISCUSSION...UPDATED 22Z...
LINE OF SCATTERED SHOWERS HAS DEVELOPED IN AN EAST-WEST BAND FROM
FEP TO RFD TO NEAR PWK. SHOWERS MOVING JUST S OF DUE EAST AND WILL
REMAIN MOSTLY NORTH OF ORD. VERY LITTLE INSTABILITY OVER NORTHEAST
IL...WITH BETTER INSTABILITY OVER WESTERN IL INTO IA. ISOLATED
THUNDER NOT OUT OF THE QUESTION BUT CHANCES OF THUNDER APPEAR LOW
THE NEXT FEW HOURS. OUTFLOW FROM A STRONGER SHOWER COULD CAUSE
SOME FLUCTUATION IN WIND SPEED AND DIRECTION AT RFD AND ORD THE
NEXT FEW HOURS.
WEAK LAKE BREEZE HAS STALLED AND APPEARS TO BE RETREATING TO THE
EAST. EXPECT THIS TREND TO CONTINUE.
ALLSOPP
PREVIOUS DISCUSSION...18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OVER WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM TO HIGH CONFIDENCE IN LAKE BREEZE STAYING EAST OF
ORD/MDW.
* MEDIUM TO HIGH CONFIDENCE IN WIND REMAINING SOUTHWEST BUT
OUTFLOW FROM SHOWERS COULD BRIEFLY CAUSE WIND TO FLUCTUATE TO
NW.
* MEDIUM CONFIDENCE IN TIMING OF ADDITIONAL SHOWERS AND ISOLATED
THUNDER LATE TONIGHT.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
330 PM CDT
AS HIGH PRESSURE CENTERED OVER THE CENTRAL GREAT LAKES SHIFTS
SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT...A GENERAL SOUTHERLY
DIRECTION CAN BE EXPECTED ACROSS THE LAKE. ALTHOUGH...A WEAK
TROUGH OF LOW PRESSURE WILL MOVE EAST THROUGH ONTARIO AND THE
NORTHERN GREAT LAKES WITH WINDS THEN EXPECTED TO BEGIN SHIFTING TO
THE WEST LATE TONIGHT. AS THIS TROUGH EXITS TO THE EAST AND HIGH
PRESSURE BUILDS SOUTH OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY AND MONDAY NIGHT...WINDS WILL TURN MORE NORTHERLY ON MONDAY
WHILE INCREASING. NORTHERLY WINDS AND WAVES WILL CONTINUE TO
INCREASE/BUILD MONDAY NIGHT INTO TUESDAY...WITH WAVES HAZARDOUS TO
SMALL CRAFT POSSIBLE ACROSS BOTH THE ILLINOIS AND INDIANA
NEARSHORE WATERS TUESDAY/TUESDAY NIGHT. WINDS AND WAVES WILL BEGIN
TO DIMINISH LATER TUESDAY NIGHT INTO WEDNESDAY...AS HIGH PRESSURE
SETTLES BACK IN.
RODRIGUEZ
&&
.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:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
330 PM CDT SUN AUG 11 2013
.DISCUSSION...
310 PM CDT
MAIN FORECAST CONCERNS FOCUS ON SHOWER/THUNDERSTORM POTENTIAL
THROUGH THE FIRST 24-36 HOURS OF THE PACKAGE...WITH THE APPROACH AND
PASSAGE OF SLOW MOVING COLD FRONT AND WEAK FRONTAL WAVE TONIGHT
THROUGH MONDAY. SURFACE HIGH PRESSURE WILL THEN SPREAD ACROSS THE
REGION MID-LATE WEEK...MAKING FOR A RELATIVELY QUIET PERIOD OF
AUGUST WEATHER...WITH TEMPERATURES AVERAGING COOLER THAN NORMAL.
THE MAIN FEATURES ON THE LOCAL WEATHER MAP THIS AFTERNOON CONSIST OF
AN AREA OF HIGH PRESSURE OVER CENTRAL ILLINOIS...WHICH CONTINUES TO
WEAKEN AND DRIFT SOUTHEAST OF THE LOCAL CWA. OF MORE INTEREST IS A
WEST-EAST SURFACE FRONTAL BOUNDARY...WHICH STRETCHES FROM THE HIGH
PLAINS OF EASTERN WYOMING...ACROSS NEBRASKA AND NORTHERN IOWA INTO
FAR NORTHWEST ILLINOIS PER 19Z ANALYSIS. WEAKENING AREAS OF
PRECIPITATION HAVE CONTINUED TO WORK EAST ACROSS SOUTHERN
MN/NORTHERN IA AND SOUTHERN WI DURING THE DAY...IN RESPONSE TO WEAK
BUT PERSISTENT WEST-SOUTHWEST LOW LEVEL FLOW INDUCED BY SHORT WAVE
PROPAGATING ACROSS THE UPPER MISSISSIPPI VALLEY...AND ASSOCIATED
WARM/MOIST ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE. WHILE
PRECIP IN THE WFO LOT CWA HAS BEEN LIMITED TO MAINLY A FEW SPRINKLES
ALONG THE IL/WI BORDER...SPC RAP MESOANALYSIS AND RAP/WRF FORECAST
SOUNDINGS CONTINUE TO DEPICT SOME WEAK INSTABILITY DEVELOPING OVER
NORTHWEST/NORTH CENTRAL IL NEAR THE SURFACE FRONT DURING THE LATE
AFTERNOON HOURS. 250-500 J/KG MUCAPE ADMITTEDLY WEAK...THOUGH
PRESENCE OF PERSISTENT WEAK CONVERGENCE/ASCENT ALONG THE BAROCLINIC
BOUNDARY DOES PRESENT SOME POTENTIAL FOR ADDITIONAL SHRA/ISOLATED
TSRA DEVELOPMENT...WITH SOME INCREASE IN CU DEVELOPMENT NOTED IN
RECENT GOES VIS IMAGERY. HAVE MAINTAINED AN ISOLATES SHRA/TSRA
MENTION AFTER 4-5 PM ACROSS PARTS OF NORTH CENTRAL ILLINOIS ROUGHLY
NORTH OF THE ROCK AND WEST OF THE FOX RIVERS.
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS THEN APPEARS TO INCREASE
FROM MID/LATE-EVENING INTO THE OVERNIGHT HOURS FROM NORTHEAST IOWA
INTO SOUTHERN WISCONSIN...AND ADJACENT PORTIONS OF NORTHERN
ILLINOIS. THIS INCREASE IS IN RESPONSE TO WEAK LARGE SCALE HEIGHT
FALLS INDICATIVE OF ASCENT WITH ADDITIONAL SHORT WAVE ENERGY
APPROACHING FROM UPSTREAM...AND INCREASING MOISTURE TRANSPORT ALONG
LOW LEVEL BAROCLINIC ZONE WITH 925-850MB WEST-SOUTHWEST 20-25 KT
FLOW AS INDICATED BY COMPLEMENTARY RAP/WRF-NAM PROGS. UPPER LEVEL
DIVERGENCE IN RIGHT ENTRANCE REGION TO UPPER LEVEL JET STREAK MAY
ALSO AID IN DEVELOPMENT FROM NORTHEAST IA INTO SOUTHWEST WI EARLIER
IN THE NIGHT...BEFORE IT TRANSLATES FARTHER EAST ACROSS MICHIGAN
LATE. WEAK SURFACE WAVE ALONG FRONT CURRENTLY OVER NORTHEAST
NEBRASKA IS PROGGED TO MOVE ACROSS SOUTHERN WI IN THE PROCESS.
WITH THE LOW LEVEL JET GRADUALLY VEERING FROM WEST-SOUTHWEST TO WEST
THROUGH THE NIGHT...THIS SHOULD HELP FOCUS FOR PRECIP SHIFT FROM
NORTHEAST IA/SOUTHWEST WI EARLY...TO SOUTHWESTERN MICHIGAN BY
SUNRISE. ALL GUIDANCE POINTS TO A FAIRLY LIMITED PORTION OF NORTHERN
IL BEING AFFECTED...PRIMARILY NORTH OF THE INTERSTATE 88 CORRIDOR.
WHILE INSTABILITY IS NOT PARTICULARLY IMPRESSIVE...UPSTREAM PWAT
VALUES ARE ROUGHLY 1.25-1.50 INCHES AND WESTERLY LOW LEVEL FLOW
MAY SUPPORT SLOW EASTWARD TRANSLATION OF RESULTING CELLS. THIS COULD
PRODUCE SOME LOCALLY HEAVY RAINFALL IF TRAINING WERE TO OCCUR.
THE TRAILING COLD FRONT IT THEN PROGGED TO PUSH SLOWLY SOUTHEAST
ACROSS THE FORECAST AREA ON MONDAY...AS THE WEAK LOW PULLS AWAY
ACROSS LOWER MICHIGAN AND DEEPER FLOW OVER THE UPPER MIDWEST BECOMES
NORTHWESTERLY WITH DIGGING UPPER TROUGH. ADDITIONAL SCATTERED SHOWER
AND THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG/AHEAD OF THE FRONT...
WITH THE GREATEST POTENTIAL ACROSS THE SOUTHEAST HALF OF THE CWA
WHERE THE FRONT WILL BE DURING THE BETTER DIURNAL INSTABILITY.
INCREASE IN MID-LEVEL FLOW ACROSS THE REGION ON MONDAY WILL LIKELY
SUPPORT A GREATER CONDITIONAL MARGINAL SEVERE WIND/HAIL THREAT
ACROSS THE SOUTHEAST COUNTIES AND AREAS EAST BY AFTERNOON.
UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHEAST CONUS INTO MONDAY
NIGHT...WITH A SECONDARY PUSH OF COOLER DRIER AIR FROM THE NORTH
HELPING TO SHOVE THE COLD FRONT OUT OF THE CWA OVERNIGHT...AND COOL
HIGH PRESSURE BUILDING SOUTHEAST ACROSS THE AREA TUESDAY-WEDNESDAY.
WITH THE MAIN UPPER TROUGH AXIS REMAINING OFF TO THE EAST OF THE
AREA...AND UPPER RIDGE TO THE WEST ACROSS ROCKIES...A PERIOD OF
FAIRLY QUIET AND COOLER THAN AVERAGE WEATHER IS ANTICIPATED. LOW
LEVEL THERMAL GUIDANCE SUGGESTS AFTERNOON HIGHS IN THE MID-UPPER 70S
DURING THE MID-WEEK PERIOD...GRADUALLY MODERATING TO THE UPPER 70S
AND LOWER 80S LATE WEEK AND NEXT WEEKEND. SOME INDICATION IN THE
LONGER RANGE GUIDANCE THAT AN UPPER LOW WILL DEVELOP ACROSS THE
LOWER OHIO OR TENNESSEE VALLEYS LATE IN THE WEEKEND...WITH BOTH THE
ECMWF AND GFS RUNS SUGGESTING THE POTENTIAL TO WRAP A LITTLE
MOISTURE INTO THE AREA FROM THE SOUTHEAST. OTHERWISE...APPEARS
MAINLY DRY THROUGH THE PERIOD BEYOND TOMORROW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
BRIEF PERIOD OF VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
330 PM CDT
AS HIGH PRESSURE CENTERED OVER THE CENTRAL GREAT LAKES SHIFTS
SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT...A GENERAL SOUTHERLY
DIRECTION CAN BE EXPECTED ACROSS THE LAKE. ALTHOUGH...A WEAK
TROUGH OF LOW PRESSURE WILL MOVE EAST THROUGH ONTARIO AND THE
NORTHERN GREAT LAKES WITH WINDS THEN EXPECTED TO BEGIN SHIFTING TO
THE WEST LATE TONIGHT. AS THIS TROUGH EXITS TO THE EAST AND HIGH
PRESSURE BUILDS SOUTH OUT OF CANADA INTO THE NORTHERN PLAINS
MONDAY AND MONDAY NIGHT...WINDS WILL TURN MORE NORTHERLY ON MONDAY
WHILE INCREASING. NORTHERLY WINDS AND WAVES WILL CONTINUE TO
INCREASE/BUILD MONDAY NIGHT INTO TUESDAY...WITH WAVES HAZARDOUS TO
SMALL CRAFT POSSIBLE ACROSS BOTH THE ILLINOIS AND INDIANA
NEARSHORE WATERS TUESDAY/TUESDAY NIGHT. WINDS AND WAVES WILL BEGIN
TO DIMINISH LATER TUESDAY NIGHT INTO WEDNESDAY...AS HIGH PRESSURE
SETTLES BACK IN.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
310 PM CDT SUN AUG 11 2013
.DISCUSSION...
310 PM CDT
MAIN FORECAST CONCERNS FOCUS ON SHOWER/THUNDERSTORM POTENTIAL
THROUGH THE FIRST 24-36 HOURS OF THE PACKAGE...WITH THE APPROACH AND
PASSAGE OF SLOW MOVING COLD FRONT AND WEAK FRONTAL WAVE TONIGHT
THROUGH MONDAY. SURFACE HIGH PRESSURE WILL THEN SPREAD ACROSS THE
REGION MID-LATE WEEK...MAKING FOR A RELATIVELY QUIET PERIOD OF
AUGUST WEATHER...WITH TEMPERATURES AVERAGING COOLER THAN NORMAL.
THE MAIN FEATURES ON THE LOCAL WEATHER MAP THIS AFTERNOON CONSIST OF
AN AREA OF HIGH PRESSURE OVER CENTRAL ILLINOIS...WHICH CONTINUES TO
WEAKEN AND DRIFT SOUTHEAST OF THE LOCAL CWA. OF MORE INTEREST IS A
WEST-EAST SURFACE FRONTAL BOUNDARY...WHICH STRETCHES FROM THE HIGH
PLAINS OF EASTERN WYOMING...ACROSS NEBRASKA AND NORTHERN IOWA INTO
FAR NORTHWEST ILLINOIS PER 19Z ANALYSIS. WEAKENING AREAS OF
PRECIPITATION HAVE CONTINUED TO WORK EAST ACROSS SOUTHERN
MN/NORTHERN IA AND SOUTHERN WI DURING THE DAY...IN RESPONSE TO WEAK
BUT PERSISTENT WEST-SOUTHWEST LOW LEVEL FLOW INDUCED BY SHORT WAVE
PROPAGATING ACROSS THE UPPER MISSISSIPPI VALLEY...AND ASSOCIATED
WARM/MOIST ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE. WHILE
PRECIP IN THE WFO LOT CWA HAS BEEN LIMITED TO MAINLY A FEW SPRINKLES
ALONG THE IL/WI BORDER...SPC RAP MESOANALYSIS AND RAP/WRF FORECAST
SOUNDINGS CONTINUE TO DEPICT SOME WEAK INSTABILITY DEVELOPING OVER
NORTHWEST/NORTH CENTRAL IL NEAR THE SURFACE FRONT DURING THE LATE
AFTERNOON HOURS. 250-500 J/KG MUCAPE ADMITTEDLY WEAK...THOUGH
PRESENCE OF PERSISTENT WEAK CONVERGENCE/ASCENT ALONG THE BAROCLINIC
BOUNDARY DOES PRESENT SOME POTENTIAL FOR ADDITIONAL SHRA/ISOLATED
TSRA DEVELOPMENT...WITH SOME INCREASE IN CU DEVELOPMENT NOTED IN
RECENT GOES VIS IMAGERY. HAVE MAINTAINED AN ISOLATES SHRA/TSRA
MENTION AFTER 4-5 PM ACROSS PARTS OF NORTH CENTRAL ILLINOIS ROUGHLY
NORTH OF THE ROCK AND WEST OF THE FOX RIVERS.
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS THEN APPEARS TO INCREASE
FROM MID/LATE-EVENING INTO THE OVERNIGHT HOURS FROM NORTHEAST IOWA
INTO SOUTHERN WISCONSIN...AND ADJACENT PORTIONS OF NORTHERN
ILLINOIS. THIS INCREASE IS IN RESPONSE TO WEAK LARGE SCALE HEIGHT
FALLS INDICATIVE OF ASCENT WITH ADDITIONAL SHORT WAVE ENERGY
APPROACHING FROM UPSTREAM...AND INCREASING MOISTURE TRANSPORT ALONG
LOW LEVEL BAROCLINIC ZONE WITH 925-850MB WEST-SOUTHWEST 20-25 KT
FLOW AS INDICATED BY COMPLEMENTARY RAP/WRF-NAM PROGS. UPPER LEVEL
DIVERGENCE IN RIGHT ENTRANCE REGION TO UPPER LEVEL JET STREAK MAY
ALSO AID IN DEVELOPMENT FROM NORTHEAST IA INTO SOUTHWEST WI EARLIER
IN THE NIGHT...BEFORE IT TRANSLATES FARTHER EAST ACROSS MICHIGAN
LATE. WEAK SURFACE WAVE ALONG FRONT CURRENTLY OVER NORTHEAST
NEBRASKA IS PROGGED TO MOVE ACROSS SOUTHERN WI IN THE PROCESS.
WITH THE LOW LEVEL JET GRADUALLY VEERING FROM WEST-SOUTHWEST TO WEST
THROUGH THE NIGHT...THIS SHOULD HELP FOCUS FOR PRECIP SHIFT FROM
NORTHEAST IA/SOUTHWEST WI EARLY...TO SOUTHWESTERN MICHIGAN BY
SUNRISE. ALL GUIDANCE POINTS TO A FAIRLY LIMITED PORTION OF NORTHERN
IL BEING AFFECTED...PRIMARILY NORTH OF THE INTERSTATE 88 CORRIDOR.
WHILE INSTABILITY IS NOT PARTICULARLY IMPRESSIVE...UPSTREAM PWAT
VALUES ARE ROUGHLY 1.25-1.50 INCHES AND WESTERLY LOW LEVEL FLOW
MAY SUPPORT SLOW EASTWARD TRANSLATION OF RESULTING CELLS. THIS COULD
PRODUCE SOME LOCALLY HEAVY RAINFALL IF TRAINING WERE TO OCCUR.
THE TRAILING COLD FRONT IT THEN PROGGED TO PUSH SLOWLY SOUTHEAST
ACROSS THE FORECAST AREA ON MONDAY...AS THE WEAK LOW PULLS AWAY
ACROSS LOWER MICHIGAN AND DEEPER FLOW OVER THE UPPER MIDWEST BECOMES
NORTHWESTERLY WITH DIGGING UPPER TROUGH. ADDITIONAL SCATTERED SHOWER
AND THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG/AHEAD OF THE FRONT...
WITH THE GREATEST POTENTIAL ACROSS THE SOUTHEAST HALF OF THE CWA
WHERE THE FRONT WILL BE DURING THE BETTER DIURNAL INSTABILITY.
INCREASE IN MID-LEVEL FLOW ACROSS THE REGION ON MONDAY WILL LIKELY
SUPPORT A GREATER CONDITIONAL MARGINAL SEVERE WIND/HAIL THREAT
ACROSS THE SOUTHEAST COUNTIES AND AREAS EAST BY AFTERNOON.
UPPER TROUGH CONTINUES TO DIG ACROSS THE NORTHEAST CONUS INTO MONDAY
NIGHT...WITH A SECONDARY PUSH OF COOLER DRIER AIR FROM THE NORTH
HELPING TO SHOVE THE COLD FRONT OUT OF THE CWA OVERNIGHT...AND COOL
HIGH PRESSURE BUILDING SOUTHEAST ACROSS THE AREA TUESDAY-WEDNESDAY.
WITH THE MAIN UPPER TROUGH AXIS REMAINING OFF TO THE EAST OF THE
AREA...AND UPPER RIDGE TO THE WEST ACROSS ROCKIES...A PERIOD OF
FAIRLY QUIET AND COOLER THAN AVERAGE WEATHER IS ANTICIPATED. LOW
LEVEL THERMAL GUIDANCE SUGGESTS AFTERNOON HIGHS IN THE MID-UPPER 70S
DURING THE MID-WEEK PERIOD...GRADUALLY MODERATING TO THE UPPER 70S
AND LOWER 80S LATE WEEK AND NEXT WEEKEND. SOME INDICATION IN THE
LONGER RANGE GUIDANCE THAT AN UPPER LOW WILL DEVELOP ACROSS THE
LOWER OHIO OR TENNESSEE VALLEYS LATE IN THE WEEKEND...WITH BOTH THE
ECMWF AND GFS RUNS SUGGESTING THE POTENTIAL TO WRAP A LITTLE
MOISTURE INTO THE AREA FROM THE SOUTHEAST. OTHERWISE...APPEARS
MAINLY DRY THROUGH THE PERIOD BEYOND TOMORROW.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
BRIEF PERIOD OF VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 PM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
//PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
BRIEF PERIOD OF VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1254 PM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
//PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LAKE BREEZE THIS AFTN WILL SHIFT WINDS TO THE SE. WINDS ARE
EXPECTED TO REMAIN LIGHT AROUND 5 KT.
* SHRA/TSRA EXPECTED AFTER MIDNIGHT THROUGH THE MORNING HOURS.
VCTS PSBL AT ORD AFTER MIDNIGHT.
JEE
//DISCUSSION...UPDATED 18Z...
STILL THINKING THE MAJORITY OF SHRA AND TSRA WILL REMAIN NORTH OF
THE TERMINALS THIS AFTN AND EVENING. INSTABILITY AND FORCING ARE
STRONGEST OVER IOWA WHERE NEW CONVECTION HAS FORMED. BKN CLOUD
COVER FROM THIS MORNINGS SHRA IS KEEPING INSTABILITY AT BAY
LOCALLY.
STILL EXPECTING A WEAK LAKE BREEZE TO PASS THROUGH THE EASTERN
TERMINALS THIS AFTN WITH WEAK SE WINDS BEHIND IT. LATER THIS
AFTN/EVENING CONVECTION SHOULD RE-FIRE OV WI. KEPT THE VCSH AT RFD
BTWN 20Z AND 00Z AS SCT SHRA MAY SINK SOUTH OR FORM ARND RFD.
DEWPOINTS ARE IN THE LOW TO MID 60S NEAR RFD AND SKIES ARE
BEGINNING TO THIN ACROSS NW IL.
THE CONVECTIVE SYSTEM THEN SINKS SOUTH AHEAD OF THE COLD FRONT
LATE TONIGHT...BUT FORCING WEAKENS ALONG THE FRONT SO EXPECTING
THE SHRA TO DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT. ALSO
EXPECTING THUNDER TO DIMINISH DUE TO DECLINING INSTABILITY SO
KEPT IT OUT OF MDW AND GYY. WINDS SHIFT TO W AND THEN NW TOMORROW
ARND 10 KT. THERE IS A CHANCE ORD WINDS MAY BECOME DUE NORTH AND
THEN FLOP OVER TO NE LATE TOMORROW AFTN. CONFIDENCE IS NOT TOO
HIGH IN THAT SITUATION GIVEN WIND SPEEDS ARND 10KT SO JUST KEPT NW
WINDS THROUGH THE END OF THE PERIOD FOR NOW.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN TIMING OF LAKE BREEZE.
* HIGH CONFIDENCE IN LIGHT SE WINDS BEHIND THE LAKE BREEZE.
* MEDIUM CONFIDENCE IN SHRA/TSRA AND TIMING TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1127 AM CDT SUN AUG 11 2013
.DISCUSSION...
1044 AM CDT
FOR MORNING UPDATE...
HAVE ADJUSTED FORECAST A BIT MAINLY TO CONFINE LOW CHANCE POPS TO
NORTHERN TIER OR TWO OF IL COUNTIES INTO THIS AFTERNOON. HAVE
REMOVED ANY MENTION OF THUNDER PRIOR TO LATE AFTERNOON.
WEAK SURFACE HIGH PRESSURE RIDGE WAS OVER IL THIS MORNING...WHILE A
NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED FROM A LEE TROUGH OVER
THE HIGH PLAINS INTO NORTHERN IA. A COUPLE AREAS OF PRECIPITATION
WERE OCCURRING FROM FAR NORTHERN IA/SOUTHERN MN INTO SOUTHERN WI AT
MID-MORNING...ASSOCIATED WITH A PAIR OF WEAK SHORT WAVE TROUGHS
PROPAGATING ALONG AND NORTH OF THE ELEVATED BAROCLINIC ZONE.
SOUTHWEST 25-30 KT FLOW IN THE 925-850MB LAYER AND ASSOCIATED
MOISTURE TRANSPORT/CONVERGENCE APPEARS TO WEAKEN SLIGHTLY AND SHIFT
INTO SOUTHERN WISCONSIN THIS AFTERNOON...MAINTAINING THREAT OF
MAINLY JUST ISOLATED/SCATTERED LIGHT SHOWERS/SPRINKLES ACROSS FAR
NORTHERN IL...WITH PERHAPS A FEW HOUR BREAK BETWEEN LIGHT ACTIVITY
NOW OVER FAR NORTHERN CHICAGO SUBURBS AND NEXT BATCH OVER NORTHERN
IA. 12Z SOUNDINGS INDICATE LITTLE/NO CAPE THIS FAR EAST...WITH
STEEPER MID-LEVEL LAPSE RATES NOTED FARTHER WEST INTO THE PLAINS.
SPC/RAP MESOANALYSIS MUCAPE DEPICTION SHOWS INSTABILITY IS LIMITED
TO AREAS WEST OF THE MISSISSIPPI RIVER THIS MORNING...THOUGH
FORECAST SOUNDINGS FROM 12Z WRF AND 12Z RAP BOTH DO DEVELOP SOME
VERY WEAK MLCAPE BY LATE THIS AFTERNOON ACROSS NORTH CENTRAL IL AS
LOW LEVELS WARM A BIT...WITH 200-400 J/KG NOTED AROUND ROCKFORD AND
VICINITY AFTER 21-22Z WHICH MAY BE ENOUGH FOR AN ISOLATED
THUNDERSTORM OR TWO. HAVE NOT MADE CHANGES FOR TONIGHT YET...WITH
GUIDANCE GENERALLY IN AGREEMENT IN REDEVELOPING/STRENGTHENING MOIST
TRANSPORT INTO THE ELEVATED FRONTAL ZONE A LITTLE FARTHER EAST ALONG
IL/WI BORDER AND AREAS EAST OVERNIGHT.
OTHERWISE...CURRENT CONVECTION-ALLOWING GUIDANCE (WRF-NMM/HRRR-SPC 4
KM WRF) ALL SUGGEST PRECIP THREAT FAIRLY MINIMAL ACROSS SOUTHERN 2/3
OR SO OF CWA THROUGH THIS AFTERNOON...AND HAVE LOWERED POPS
ACCORDINGLY. DID TWEAK SKY COVER UP A BIT NORTH OF I-80 BASED ON
SATELLITE TRENDS THIS MORNING...AND ADJUSTED HOURLY TEMP TRENDS
ESPECIALLY NORTH CENTRAL IL WHERE CLOUDS HAVE SLOWED WARMING THIS
MORNING.
RATZER
//PREV DISCUSSION...
341 AM CDT
THE PRIMARY FORECAST CONCERN CONTINUES TO BE ON SHRA/TSRA CHANCES
TODAY THROUGH MONDAY EVENING.
A LOOSELY ORGANIZED MCS CURRENTLY OVER SOUTHERN MN AND NORTHERN IA
WILL TRACK EAST SOUTHEAST TOWARD SRN WI AND FAR NORTHERN IL BUT
COMPLETELY OUTRUN ANY ELEVATED INSTABILITY SO WOULDNT BE SURPRISED
THAT ALL THAT MAKES IT INTO FAR NORTHERN CWA MID MORNING AND EARLY
AFTERNOON IS A FEW SHOWERS OR MAYBE EVEN JUST SPRINKLES. HAVE KEPT
LOW CHANCE POPS CONFINED TO NEAR THE WISCONSIN BORDER. THE MAIN
IMPACT OF THIS FEATURE WILL LIKELY BE THAT ITS CLOUD COVER WILL
LIMIT WARMING POTENTIAL OVER THE NORTHERN 1/2 OR SO OF THE CWA
DESPITE THERMAL PROFILES THAT WOULD FAVOR HIGHS INTO THE MID 80S.
MID AND UPPER 70S ARE NOW EXPECTED ALONG THE WISCONSIN BORDER
TRENDING UPWARD TO THE MID 80S IN THE FAR SOUTH WHERE MUCH LESS
CLOUD COVER IS ANTICIPATED.
AFTER THE CLUSTER OF SHRA/TSRA FALLS APART BY EARLY
AFTERNOON...THERE COULD BE BREAKS DEVELOPING IN THE CLOUD COVER OVER
THE NORTHERN CWA. ATTENTION WILL TURN TO WARM FRONTAL BOUNDARY
LIFTING NORTH INTO NORTH CENTRAL ILLINOIS. GUIDANCE INDICATES MODEST
MOISTURE CONVERGENCE ON THE LEADING EDGE OF THE ELEVATED WARM
FRONT...SO COULD POSSIBLY SEE SCATTERED SHRA AND TSRA DEVELOPMENT IN
THE LATE AFTERNOON AND EARLY EVENING PUSHING NORTHEAST WITH THE
FRONT. STRONG NORTHWESTERLY FLOW ALOFT WILL BE OFFSET BY LIMITED
INSTABILITY...POSSIBLY A FEW HUNDRED J/KG.
WHILE THE SURFACE AND ELEVATED WARM FRONT ARE LIFTING NORTHEAST IN
THE EVENING...GUIDANCE IS VERY CONSISTENT IN DEPICTING STRENGTHENING
925 TO 850 MOISTURE TRANSPORT AND STRONG MOISTURE CONVERGENCE ON THE
NOSE OF THIS FOCUSED INTO SOUTHERN WISCONSIN BEFORE SHIFTING EAST.
BUMPED POPS ALONG THE WISCONSIN BORDER TO THE LIKELY CATEGORY...AND
THE EXACT PLACEMENT OF THE CONVERGENCE AXIS WILL DETERMINE IF THESE
AREAS WILL SEE DECENT RAINFALL AMOUNTS OR THE FOCUS IS EVEN FURTHER
NORTH INTO WISCONSIN THAN CURRENTLY DEPICTED. SUPPORTING DECENT
RAINFALL AMOUNTS WILL BE PWAT VALUES APPROACHING 1.5 INCHES OR
POSSIBLY HIGHER. FARTHER SOUTH DOWN TO THE I-80 AND I-88
CORRIDORS...INCREASED LOW LEVEL JET FORCING AND DISTURBED
WEST-NORTHWEST FLOW AT THE MID LEVELS IS EXPECTED TO SUPPORT
FESTERING SCATTERED SHRA AND TSRA DEVELOPMENT. LOW TEMPERATURES WILL
BE SEVERAL DEGREES WARMER THAN THIS MORNING DUE TO WARM ADVECTION
AND CLOUD COVER.
ON MONDAY INTO MONDAY EVENING...A MORE OR LESS WEST-EAST ORIENTED
COLD FRONT TRAILING SOUTHWARD FROM LOW PRESSURE WELL OFF TO THE
NORTHEAST WILL BE PUSHING SOUTHWARD THROUGH THE AREA. DESPITE
ANTICIPATION OF AT LEAST BROKEN CLOUD COVER...850 TEMPS IN THE MID
TEENS AND 925 TEMPS AROUND 20C OR EVEN HIGHER WILL SUPPORT HIGHS
FROM AROUND 80 NORTH TO THE MID TO POSSIBLY EVEN A FEW UPPER 80S FAR
SOUTH. THE TIMING OF THE FRONTAL PASSAGE WILL DICTATE THE EXTENT OF
THE THUNDERSTORM THREAT...THOUGH HAVE MOST CONFIDENCE IN THE
SOUTHERN HALF OF THE AREA SEEING AT LEAST SCATTERED DEVELOPMENT EVEN
WITH A FASTER FROPA.
AS COLD FRONTS TEND TO DO THIS TIME OF YEAR...AM BANKING ON A SLOWER
PROGRESSION OF THE FRONT AND THUS GOOD INSTABILITY/POTENTIALLY IN
EXCESS OF 1500-2000 J/KG OF MLCAPE/ALL THE WAY TO THE NORTHERN CWA
BORDER BY LATE MORNING...WHICH IS SHOWN WELL BY FORECAST SOUNDINGS.
WITH GUIDANCE INDICATING GOOD CONVERGENCE ALONG AND FRONT AND UP TO
850 MB...HAVE BUMPED POPS TO THE HIGH CHANCE RANGE PROGRESSING
SOUTHWARD INTO THE EARLY EVENING. THOUGH FLOW ALOFT STARTS OUT
MARGINAL...IT AND CONCORDANTLY DEEP LAYER DO INCREASE INTO THE
AFTERNOON...WITH VALUES APPROACHING 40 KT. THUS CONTINUE TO BE
CONCERNED FOR STRONG TO SEVERE TSRA DEVELOPMENT. ORIENTATION OF
STEERING FLOW TO FRONT WOULD INDICATE MULTICELLS OR SMALL LINE
SEGMENTS CAPABLE OF PRODUCING DAMAGING OR GUSTY WINDS ARE POSSIBLE.
THE SPC DAY 2 OUTLOOK HAS MOST OF THE AREA UNDER A SEE TEXT AND 5%
SEVERE PROBABILITIES.
STRONG COOL ADVECTION WILL COMMENCE BEHIND THE FRONT TOMORROW NIGHT
INTO TUESDAY...THOUGH THE COOLEST THERMAL PROFILES WILL NOT ARRIVE
UNTIL TUESDAY NIGHT AND WEDNESDAY. THEREFORE...TUESDAY LOOKS TO BE A
BEAUTIFUL DAY WITH HIGHS FAVORED IN THE UPPER 70S (POSSIBLY A FEW 80
READINGS IN THE FAR SOUTH) AWAY FROM LAKE MICHIGAN...AND LAKESHORE
AREAS LIMITED TO THE LOWER 70S BY ONSHORE FLOW. AFTER A CHILLY
TUESDAY NIGHT WITH RURAL/SUBURBAN LOWS IN THE LOWER-MID 50S 850 MB
TEMPS BELOW +9 AND 925 TEMPS BELOW +13 ON WEDNESDAY WILL RESULT IN
A COOL BUT STILL PLEASANT DAY WITH HIGHS IN THE MID 70S. THE DEEP
TROUGH OVER THE NORTHEASTERN 1/3 OF THE CONUS WILL GRADUALLY LIFT
THURSDAY THROUGH THE SATURDAY...SUPPORTING GRADUALLY WARMING
TEMPERATURES FROM THEIR MID WEEK MINIMUM...BUT SURFACE HIGH PRESSURE
LOCKED OVER THE REGION WILL RESULT IN AN EXTENDED PERIOD OF DRY
WEATHER.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* LAKE BREEZE THIS AFTN WILL SHIFT WINDS TO THE SE. WINDS ARE
EXPECTED TO REMAIN LIGHT AROUND 5 KT.
* SLIGHT CHANCE OF SHRA/TSRA LATE THIS EVENING WITH A BETTER
CHANCE OF SHRA/TSRA LATE TONIGHT INTO MONDAY MORNING.
JEE
//DISCUSSION...UPDATED 16Z...
MADE SOME ADJUSTMENTS BASED ON CURRENT TRENDS AND LATEST GUIDANCE.
WINDS HAVE TURNED EAST ALONG THE LAKESHORE BUT THINKING THE WINDS
WILL BE MORE SE WHEN THE LAKE BREEZE MOVES THROUGH THE EASTERN
TERMINALS. ALSO THINKING THE SE WINDS WILL BE LIGHT AROUND 5 KT AS
THE DOWNTOWN OB HAS BEEN STEADY ARND 5 KT SINCE THE WIND TURNED
EAST.
LOOKING AT PRECIP TODAY...THINKING THE VAST MAJORITY OF SHRA/TSRA
WILL REMAIN NORTH OF THE TERMINALS ALONG THE STATIONARY BOUNDARY
OVER SOUTHERN WI. GUIDANCE DOES SUGGEST THE LINE MAY SINK SOUTH A
BIT WITH SHRA IN THE VICINITY OF RFD LATE THIS AFTN...THEREFORE
PUT A VCSH IN AT RFD AFT 20Z. GUIDANCE HAS THE FRONT
SINKING SOUTH A BIT LATER SO PUSHED CHANCES OF PRECIP BACK A FEW
HOURS. RFD WILL BE IMPACTED FIRST. NOT SURE HOW MUCH INSTABILITY
WILL BE AROUND SO WENT WITH A HIGHER CHANCE OF SHRA THAN TS...BUT
CANNOT COMPLETELY RULE TS OUT AT RFD. FOR THE EASTERN
TERMINALS...SHRA MAY ARRIVE EVEN LATER THAN CURRENTLY INDICATED BUT
DECIDED TO PUSH THE PRECIP BACK INCREMENTALLY.
PREVIOUS DISCUSSION...12Z...
TRICKY FORECAST THIS MORNING IN TERMS OF SHRA/TSRA CHANCES AND
WIND DIRECTION TRENDS. HIGH PRESSURE REMAINS OVER THE AREA BUT
WILL BE SLIDING SOUTHEASTWARD THROUGH THE DAY AS A COOL FRONTAL
BOUNDARY DROPS SOUTHWARD FROM ONTARIO AND EVENTUALLY CROSSES THE
AREA MONDAY. IN THE MEANTIME...AN UPPER LEVEL DISTURBANCE AND
ASSOCIATED MID LEVEL WARM ADVECTION GENERATED A SMALL SHRA/TSRA
COMPLEX WHICH IS NOW SHOWING SIGNS OF DECAY OVER NORTH-CENTRAL
IOWA. THIS WILL BE THE FIRST CHANCE FOR SHRA AT THE TERMINALS BUT
THERE MAY NOT BE MUCH LEFT OF IT BY MID MORNING WHICH IS WHEN IT
WOULD ARRIVE AT RFD. HAVE RETAINED VCSH MENTION AT RFD TO ACCOUNT
FOR THE POTENTIAL FOR SOME LIGHT RAIN OR SPRINKLES. SHOULD THIS
PRECIP HOLD TOGETHER IT WOULD REACH THE CHI AREA TERMINALS TOWARD
MIDDAY BUT HAVE A HARD TIME SEEING MUCH MORE THAN SOME LIGHT RAIN
OR SPRINKLES BY THEN. WARM ADVECTION WILL REMAIN IN PLACE ALOFT
WHICH MAY HELP TRIGGER SOME ISOLD/SCT DEVELOPMENT THIS AFTERNOON
BUT AM THINKING THAT THE BETTER CHANCES WILL ARRIVE THIS EVENING
AND EARLY TONIGHT AS THE LOW LEVEL JET INTENSIFIES TO THE WEST.
WILL CONTINUE WITH PROB30 FOR TS DURING THE EVENING HOURS WITH
SOME ACTIVITY POSSIBLE...BUT IT APPEARS THE BULK OF ANY ACTIVITY
WILL BE NORTH OF THE WISCONSIN BORDER. ADDITIONAL CHANCES WILL BE
IN PLACE MONDAY AS THE AFOREMENTIONED COLD FRONT CROSSES THE AREA
BUT THE EXTENT OF THE ACTIVITY WILL LIKELY DEPEND ON HOW ACTIVITY
EVOLVES TONIGHT SO WILL KEEP THE LATER PART OF THE 30 HR ORD TAF
DRY. THE FRONT MAY SLOW SO HAVE OPTED TO KEEP A SOUTHWEST WIND
MONDAY MORNING.
IN TERMS OF WINDS...WITH THE HIGH OVERHEAD MOST LOCATIONS HAVE
BEEN CALM OVERNIGHT WITH A FEW SITES STARTING TO REGISTER SOME
LIGHT WINDS. EXPECT A WEST TO WEST-NORTHWEST DIRECTION THIS
MORNING WITH SPEEDS REMAINING QUITE LIGHT. A LAKE BREEZE IS
EXPECTED TO DEVELOP LATE THIS MORNING AND MOVE INLAND TURNING
WINDS EASTERLY AND WILL CONTINUE WITH THE IDEA OF IT CROSSING
ORD/MDW LATER THIS AFTERNOON. THIS WILL NEED TO BE WATCHED CLOSELY
THOUGH BECAUSE AN INFLUX OF CLOUD COVER COULD PREVENT ITS
DEVELOPMENT AS COULD ANY SORT OF OUTFLOW FROM THE DECAYING
SHRA/TSRA COMPLEX. WINDS THEN TURN SOUTH TO SOUTHEAST THIS EVENING
RETURNING TO SOUTHWEST OVERNIGHT AS THE PRESSURE GRADIENT
TIGHTENS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE IN TIMING OF LAKE BREEZE.
* HIGH CONFIDENCE IN LIGHT SE WINDS BEHIND THE LAKE BREEZE.
* MEDIUM CONFIDENCE IN DRY CONDITIONS THROUGH THIS AFTN AND TIMING
OF SHRA/TSRA LATE TONIGHT/MONDAY MORNING. SHRA/TSRA MAY ARRIVE
EVEN LATER.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT THROUGH SATURDAY...VFR NO SIG WEATHER.
MDB
&&
.MARINE...
248 AM CDT
HIGH PRESSURE REMAINS SPREAD FROM PENNSYLVANIA BACK INTO ILLINOIS
AND MISSOURI BUT WILL BE SLOWLY SLIDING SOUTHEASTWARD THROUGH
TOMORROW. LOW PRESSURE WILL THEN MOVE FROM CENTRAL AND NORTHERN
ONTARIO EASTWARD ACROSS QUEBEC TONIGHT INTO MONDAY. A COLD FRONT
WILL EXTEND SOUTHWESTWARD FROM THE LOW AND DROP SOUTHWARD DOWN THE
LAKE MONDAY. SOUTHERLY WINDS WILL BE IN PLACE AHEAD OF THE FRONT BUT
TURN NORTHERLY BEHIND IT AS STRONG HIGH PRESSURE SPREADS IN MONDAY
NIGHT AND TUESDAY. THIS WILL ALLOW THE PRESSURE GRADIENT TO TIGHTEN
AND COMBINE WITH COOL AIR ADVECTION TO PRODUCE INCREASED WINDS
MONDAY NIGHT AND TUESDAY WITH STEADY 15 TO 20 KT SPEEDS EXPECTED
WITH GUSTS TO 25 KT POSSIBLE...MAINLY SOUTH. THE LONG FETCH WILL
KICK WAVES UP TO THE 4 TO 6 FT RANGE SOUTH AND ACROSS THE ILLINOIS
AND INDIANA NEARSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
IF THESE WINDS MATERIALIZE. THE STRONG HIGH PRESSURE SYSTEM WILL BE
CENTERED OVER LAKE MICHIGAN FROM TUESDAY NIGHT THROUGH EARLY NEXT
WEEKEND LEADING TO A PERIOD OF LIGHT WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1225 PM CDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 1216 PM CDT SUN AUG 11 2013
IT HAS RAINED LITTLE MORE THAN A FEW ISOLATED SPRINKLES THUS FAR
TODAY...AND IT APPEARS THERE IS LITTLE THREAT FOR ANYTHING MORE
THAN THIS UNTIL MID AFTERNOON. I HAVE DONE SEVERAL UPDATES TO
REDUCE POPS NORTH...AND UNTIL WE SEE NEW CONVECTION FORMING
NORTHERN IOWA...WE MAY NEED MORE UPDATES TO DRY THE FORECAST OUT
MORE SO. TEMPERATURES HAVE BEEN BUMPED UP TO LOWER TO MID 80S IN
MOST LOCATIONS GIVEN THE LACK OF DENSE PERSISTENT CLOUD COVER
SOUTH OF HIGHWAY 20.
ERVIN
&&
.SYNOPSIS...
ISSUED AT 305 AM CDT SUN AUG 11 2013
06Z SFC ANALYSIS HAS A WEAK LOW NEAR KICR WITH A STATIONARY FRONT
SOUTHEAST INTO WESTERN IOWA. A WEAK BOUNDARY RAN FROM SOUTHEAST
SOUTH DAKOTA INTO NORTHERN IOWA. DEW POINTS WERE IN THE 50S ACROSS
THE GREAT LAKES WITH 60S IN THE PLAINS AND 70S ACROSS THE DEEP SOUTH
AND OHIO VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN AUG 11 2013
THE MCS AND LIFT TOOLS WHEN APPLIED TO TRENDS IN THE RAP AND OTHER
MODELS SUGGEST A MAJORITY OF THE PRECIPITATION WILL REMAIN NORTH OF
THE CWFA THROUGH MID DAY WITH SOME SHOWERS BRUSHING THE NORTHERN
CWFA IN THE HIGHWAY 20 CORRIDOR. RECENT TRENDS WITH THE RAP SUGGEST
PRECIPITATION MAY NOT BEGIN ENTERING THE NORTHERN CWFA UNTIL AROUND
SUNRISE.
PRECIPITATION SHOULD WANE DURING THE LATE MORNING AND EARLY
AFTERNOON BEFORE RE-DEVELOPING THIS AFTERNOON HOURS DURING MAX
HEATING. ANY PRECIPITATION IN THE HWY 20 CORRIDOR WILL EXPAND
SOUTHWARD TO HWY 30 AND EVENTUALLY TO I-80 BY LATE AFTERNOON.
TONIGHT...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL BE ACROSS
ROUGHLY THE NORTHERN HALF OF THE CWFA DURING THE EVENING BEFORE
SLOWLY SPREADING SOUTH AFTER MIDNIGHT. THE EXTREME SOUTHERN PART OF
THE CWFA CURRENTLY LOOKS TO BE DRY BOTH TODAY AND TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN AUG 11 2013
RAIN CHANCES LINGER EARLY IN THE WEEK THEN MAINLY DRY AND PLEASANT
REST OF THE PERIOD WITH NEAR TO BELOW NORMAL TEMPS.
MON-MON NGT... SURFACE AND 850 MB COLD FRONTS WILL GRADUALLY SLIDE
THROUGH THE AREA AS AN UPPER LEVEL TROUGH MOVES INTO THE GREAT
LAKES. 850 MB BOUNDARY IS SUGGESTED TO BE PRIMARY PCPN MECHANISM
DUE TO BETTER CONVERGENCE WITH SCATTERED ELEVATED SHOWERS AND
ISOLD STORMS MAINLY NORTH OF I-80 MON AM SLIDING SOUTHEAST IN THE
PM. CONVERGENCE ALONG SURFACE FRONT FAIRLY WEAK BUT IF SUFFICIENT
HEATING INTO THE MID 80S THEN CAPPING INVERSION SHOULD WEAKEN AND
JUST ENOUGH CONVERGENCE TO ALLOW SCATTERED STORMS TO DEVELOP FROM
MID PM TO EARLY EVE MAINLY JUST S/SE OF QUAD CITIES. ENVIRONMENT
LOOKS LIKE FAIRLY WEAK TO MARGINAL SHEAR (0-6KM BULK SHEAR 20-25 KTS)
AND MODERATE INSTABILITY (MUCAPES 1500-2000+ J/KG)... THUS MARGINAL
ISOLD PULSE TYPE STORMS SUGGESTED WITH SOME SMALL HAIL AND DOWNBURST
WINDS POSSIBLE. BANKING ON ANY PCPN MAINLY SCATTERED AND ENOUGH
BREAKS IN CLOUDS TO YIELD WIDESPREAD 80S FOR HIGHS WITH THE WARMEST
READINGS ACROSS THE SOUTHERN CWA. RAIN CHCS LINGER MON EVE ACROSS THE
SOUTH...THEN HIGH PRESSURE RIDGE BEGINS TO BUILD IN OVRNGT BRINGING IN
DRIER AIR. LOWS MON NGT COOLEST NORTH WHERE SOME 50S WHILE 60S ARE
LIKELY ELSEWHERE.
TUE-TUE NGT... UKMET IS AN OUTLIER HOLDING UP MID LEVEL BAROCLINIC
ZONE ACROSS SOUTHERN CWA AND GENERATING SOME ADDITIONAL PCPN ON TUE.
HAVE SIDED TOWARD CONSENSUS FCST WITH CONTINUED DRY AND COOL
ADVECTION WITH STRENGTHENING NORTHWEST FLOW ALOFT AND INCOMING SURFACE
RIDGE SHUNTING BAROCLINIC ZONE AND PCPN PROCESSES SOUTH/WEST OF THE
CWA. HIGHS TUE RANGING FROM SOME MID 70S NORTH TO LOWER 80S SOUTH WITH
PT-MOSUNNY SKIES. CONTINUED LOWERING OF DEWPTS MAINLY INTO THE 50S
COUPLED WITH N/NE WINDS 5-10 MPH SHOULD MAKE FOR A REAL NICE AND
VERY COMFORTABLE DAY FOR OUTDOOR ACTIVITIES. COOL CONDITIONS EXPECTED
TUE NGT WITH CLEARING SKIES AND LIGHT WINDS ALLOWING FOR WIDESPREAD
LOWS IN THE 50S.
WED-SAT...FLOW ALOFT WILL REMAIN NORTHWEST WITH LARGE EXPANSE OF HIGH
PRESSURE AT THE SURFACE SLOWLY SHIFTING FROM THE UPPER MIDWEST INTO
THE OH VLY. RESULT WILL BE A PROLONGED PERIOD OF FANTASTIC WX FEATURING
LOW HUMIDITY...LIGHT WINDS...MAINLY CLEAR SKIES AND SLIGHTLY BELOW
NORMAL TEMPS WITH HIGHS MAINLY IN THE UPPER 70S TO LOWER 80S AND LOWS IN
THE 50S TO AROUND 60F.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1216 PM CDT SUN AUG 11 2013
A WEAK FRONT WILL MOVE THROUGH EASTERN IOWA TODAY...BRINGING A LOW
THREAT FOR SCATTERED SHOWERS. AN ISOLATED STORM CANNOT BE RULED
OUT...BUT THIS THREAT WILL BE TOO LOW TO INCLUDED MENTION IN TAFS.
OTHERWISE...EXPECTED PARTLY TO MOSTLY CLOUDY SKIES THROUGH
TOMORROW...WITH MAINLY MID CLOUDS BETWEEN 5000 FT AND 10000 FT
CIGS. WINDS WILL BE 6 TO 10 KTS FROM THE SOUTHWEST THROUGH SUNSET
TODAY...THEN LIGHT AND VARIABLE OVERNIGHT...AND AFTER 15Z
MONDAY...NORTH WINDS OF 6 TO 10 KTS ARE EXPECTED BEHIND THE WEAK
FRONT. DURING THE PERIOD OF NEARLY CALM WINDS TONIGHT...THERE IS A
LOW THREAT FOR FOG. THIS TREND WILL BE WATCHED CAREFULLY FOR
POTENTIAL MVFR FOG CONDITIONS IF SKIES CAN BE CLEAR AT THE SAME
TIME PERIOD.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...ERVIN
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS JACKSON KY
134 PM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 107 PM EDT SUN AUG 11 2013
HAD TO ISSUE ANOTHER QUICK UPDATE TO THE FORECAST. THE INHERITED
FORECAST HAD THE HIGHEST PRECIPITATION PROBABILITIES ALONG AND JUST
NORTH AND WEST OF THE TENNESSEE AND VIRGINIA BORDERS RESPECTIVELY.
HOWEVER...SHOWERS AND STORMS IN THAT AREA HAVE DISSIPATED ALMOST
COMPLETELY OVER THE PAST COUPLE OF HOURS. WITH SCATTERED SHOWERS AND
STORMS NOW FIRING IN VICINITY OF THE FRONTAL BOUNDARY WELL NORTH OF
THE TENNESSEE LINE...THE FORECAST POPS...SKY COVER...AND QPF HAD TO
ALL BE MODIFIED TO REFLECT THIS NEW TRENDS. THEREFORE...PRECIPITATION
CHANCES FOR AREAS NORTH OF THE HAL ROGERS PARKWAY WERE INCREASED TO
50 PERCENT FOR THE REST OF THE DAY...WHILE THE POPS SOUTH OF THERE
WERE LOWERED DRAMATICALLY AND SLOWLY RAMPED UP TOWARD LATE
AFTERNOON...AS THE FRONT...AND THE WAVE OF LOW PRESSURE THAT HAS
FORMED ALONG IT...MOVE OFF TO THE EAST. THE UPDATED ZONES HAVE
ALREADY BEEN SENT.
UPDATE ISSUED AT 1047 AM EDT SUN AUG 11 2013
MADE A FEW UPDATES TO THE INHERITED FORECAST. REMOVED THE PRE-FIRST
PERIOD THAT WAS INCLUDED WITH THE 4 AM FORECAST PACKAGE...AND REMOVED
MENTION OF EARLY MORNING FOG. THE HIGHER PRECIPITATION CHANCES FROM
EARLIER THIS MORNING WERE ALSO REMOVED FROM THE TODAY PERIOD...AS THE
AREA IS CURRENTLY EXPERIENCING A LULL IN SHOWERS AND STORMS.
HOWEVER...WITH A SLUGGISH FRONTAL BOUNDARY MEANDERING ABOUT ACROSS
THE AREA...ANTICIPATE THAT SHOWERS AND STORMS WILL AGAIN INCREASE IN
COVERAGE AS THE DAY WEARS ON...PARTICULARLY ALONG AND SOUTH OF THE
HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDOR. LOCALLY HEAVY RAINFALL
WILL REMAIN A POSSIBILITY THROUGHOUT THE DAY WHERE MORE WIDESPREAD
SHOWERS AND STORMS OCCUR.
UPDATE ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO OUT OF SORTS IN THIS PATTERN TO
BITE ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE
RUN. DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A
THREAT FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN AUG 11 2013
A VERY CHALLENGING TAF FORECAST YET AGAIN TODAY. AN WEST TO EAST
ORIENTED LINE OF SHOWERS AND THUNDERSTORMS HAS FORMED AND IS MOVING
ALONG THE MOUNTAIN PARKWAY. THESE SHOWERS AND STORMS ARE EXPECTED TO
INCREASE IN COVERAGE AS THE AFTERNOON WEARS ON AND EXPAND SOUTH AS
A FRONTAL BOUNDARY AND A WAVE OF LOW PRESSURE MOVE EAST ACROSS THE
AREA. JKL WILL SEE THE FIRST ROUND OF SHOWERS AND STORMS TODAY AND
COULD EXPERIENCE PERIODS OF MVFR CONDITIONS WHILE THE RAIN IS
FALLING. LOZ AND SME SHOULD BE OFF THE HOOK UNTIL 20 OR 21Z...AS THE
AFOREMENTIONED WEATHER SYSTEMS MAKES ITS WAY EASTWARD. MVFR
CONDITIONS WILL ALSO BE EXPECTED AT LOZ AND SME WHEN SHOWERS AND
STORMS EVENTUALLY AFFECT THOSE TAF SITES DIRECTLY. LATER
TONIGHT...AFTER 5Z OR SO...FOG IS ON TAP FOR THE TAF SITES...AS
COOLER AIR SETTLES IN BEHIND THE FRONT. CONSIDERING THE AMOUNT OF
RAIN THAT HAS FALLEN ACROSS THE ENTIRE AREA THE PAST SEVERAL
DAYS...AND WITH PARTLY CLOUDY SKIES AND LIGHT WINDS EXPECTED...FOG
WILL BE A GOOD BET LATER TONIGHT INTO EARLY TOMORROW MORNING. IN
GENERAL...IFR CONDITIONS ARE EXPECTED WHEN THE FOG IS AT ITS WORST
AND JKL AND LOZ...BUT THERE COULD BE BRIEF PERIODS OF LIFR CONDITIONS
TOWARDS DAWN TOMORROW...AS THE RAIN OF THE PAST SEVERAL DAYS HAS
SATURATED THE GROUND AT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
107 PM EDT SUN AUG 11 2013
.UPDATE...
ISSUED AT 107 PM EDT SUN AUG 11 2013
HAD TO ISSUE ANOTHER QUICK UPDATE TO THE FORECAST. THE INHERITED
FORECAST HAD THE HIGHEST PRECIPITATION PROBABILITIES ALONG AND JUST
NORTH AND WEST OF THE TENNESSEE AND VIRGINIA BORDERS RESPECTIVELY.
HOWEVER...SHOWERS AND STORMS IN THAT AREA HAVE DISSIPATED ALMOST
COMPLETELY OVER THE PAST COUPLE OF HOURS. WITH SCATTERED SHOWERS AND
STORMS NOW FIRING IN VICINITY OF THE FRONTAL BOUNDARY WELL NORTH OF
THE TENNESSEE LINE...THE FORECAST POPS...SKY COVER...AND QPF HAD TO
ALL BE MODIFIED TO REFLECT THIS NEW TRENDS. THEREFORE...PRECIPITATION
CHANCES FOR AREAS NORTH OF THE HAL ROGERS PARKWAY WERE INCREASED TO
50 PERCENT FOR THE REST OF THE DAY...WHILE THE POPS SOUTH OF THERE
WERE LOWERED DRAMATICALLY AND SLOWLY RAMPED UP TOWARD LATE
AFTERNOON...AS THE FRONT...AND THE WAVE OF LOW PRESSURE THAT HAS
FORMED ALONG IT...MOVE OFF TO THE EAST. THE UPDATED ZONES HAVE
ALREADY BEEN SENT.
UPDATE ISSUED AT 1047 AM EDT SUN AUG 11 2013
MADE A FEW UPDATES TO THE INHERITED FORECAST. REMOVED THE PRE-FIRST
PERIOD THAT WAS INCLUDED WITH THE 4 AM FORECAST PACKAGE...AND REMOVED
MENTION OF EARLY MORNING FOG. THE HIGHER PRECIPITATION CHANCES FROM
EARLIER THIS MORNING WERE ALSO REMOVED FROM THE TODAY PERIOD...AS THE
AREA IS CURRENTLY EXPERIENCING A LULL IN SHOWERS AND STORMS.
HOWEVER...WITH A SLUGGISH FRONTAL BOUNDARY MEANDERING ABOUT ACROSS
THE AREA...ANTICIPATE THAT SHOWERS AND STORMS WILL AGAIN INCREASE IN
COVERAGE AS THE DAY WEARS ON...PARTICULARLY ALONG AND SOUTH OF THE
HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDOR. LOCALLY HEAVY RAINFALL
WILL REMAIN A POSSIBILITY THROUGHOUT THE DAY WHERE MORE WIDESPREAD
SHOWERS AND STORMS OCCUR.
UPDATE ISSUED AT 720 AM EDT SUN AUG 11 2013
HAVE UPDATED THE GRIDS TO REFLECT THE SHOWERS AND THUNDERSTORMS...
ALONG WITH HEAVY RAINS...MOVING THROUGH THE HEADWATERS OF THE
CUMBERLAND VALLEY. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 325 AM EDT SUN AUG 11 2013
06Z SFC ANALYSIS SHOWS EAST KENTUCKY IN THE MIDST OF A WASHED OUT
BOUNDARY. THIS IS HELPING TO INITIATE ANOTHER REDEVELOPMENT OF
SHOWERS...AND PROBABLY EVENTUAL THUNDERSTORMS...OVER THE CUMBERLAND
VALLEY. THE EARLIER ROUNDS OF STORMS AND HEAVY RAINS LEFT BEHIND
STRETCHES OF THOROUGHLY SATURATED GROUND ACROSS A GOOD PORTION OF
EAST KENTUCKY. THESE PLACES WILL HAVE TO WATCHED CLOSELY DURING THE
REST OF THE NIGHT...AND INTO TODAY...FOR ANY NEW HEAVY RAIN THREATS.
OTHERWISE...THE PARTLY CLOUDY SKIES...WET BOUNDARY LAYER...AND LIGHT
WINDS HAVE BEEN ENOUGH FOR AREA OF FOG TO DEVELOP ACROSS THE AREA
ALONG WITH LOCALLY DENSE PATCHES. THIS MUGGY AND MOIST ENVIRONMENT IS
FURTHER EVIDENCED BY THE CURRENT TEMPERATURES AND DEWPOINTS IN OUR
COVERAGE AREA ALL BEING WITHIN A DEGREE OR TWO OF 70.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION
OF THE FORECAST AS THEY ALL DEPICT CONFLUENT FLOW OVER THE OHIO
VALLEY BETWEEN A DEEP TROUGH OVER SOUTHEAST CANADA AND FLAT RIDGING
ABOVE THE DEEP SOUTH. THIS FLOW WILL CONTAIN SOME WEAK BATCHES OF MID
LEVEL ENERGY RIPPLING PAST DURING THE NEXT 24 HOURS. THESE WAVES...AS
MODELED...ARE LESS NOTE WORTHY THAN THOSE OF THE PAST SEVERAL DAYS.
ACCORDINGLY...A DIMINISHMENT OF THE UPPER LEVELS IMPACT ON WEATHER
AND TIMING IS EXPECTED FOR TODAY INTO MONDAY. AS A RESULT...EXPECT THE
WEATHER FOR EAST KENTUCKY TO BE MOST DETERMINED BY MORE MESOSCALE
AND NEAR SFC FEATURES DURING THE NEXT 24 TO 48 HOURS. THEREFORE...
HAVE FAVORED THE LATEST GUIDANCE FROM THE NAM12 MOST HEAVILY WITH
SOME INFLUENCE FROM THE ECMWF AND...IN THE NEAR TERM...WHERE
REASONABLE...THE HRRR.
SENSIBLE WEATHER WILL FEATURE ANOTHER PERIOD OF DEALING WITH A NEARBY
FRONTAL BOUNDARY IN AN ENVIRONMENT OF HIGH MOISTURE. THIS BOUNDARY IS
EXPECTED TO SLIP SOUTH LATER TODAY AND TONIGHT BEFORE LIFTING BACK
NORTH ON MONDAY. THE MOVEMENT SHOULD PROVIDE SOME BOUNDS FOR THE
GREATEST THREAT OF SHOWER AND THUNDERSTORM ACTIVITY...PRIMARILY
DIURNALLY DRIVEN...THROUGH MONDAY. HAVE COMPOSED THE POP AND WX GRIDS
WITH THIS IN MIND IN CONJUNCTION WITH PRIMARILY THE NAM12
GUIDANCE...AS THE HRRR IS JUST TOO OUT OF SORTS IN THIS PATTERN TO
BITE ON ITS PATTERNS...BEYOND THE NEXT FEW HOURS OF EACH SUCCESSIVE
RUN. DUE TO THE HIGH PW AIR AND THE POTENTIAL FOR TRAINING STORMS A
THREAT FOR HEAVY TO EXCESSIVE RAIN REMAINS TODAY...BUT PRIMARILY FOR
LOCATIONS ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. WILL CONTINUE TO
HIT THIS IN THE HWO...BUT HAVE LIMITED TO JUST THE SOUTHERN ZONES IN
THE WX GRIDS FOR NOW. WITH A BIT MORE CLEARING AND SLIGHTLY LOWER
DEWPOINTS TONIGHT WOULD EXPECT MORE IN THE WAY OF FOG...LOCALLY
DENSE. HAVE ADDED THIS TO THE WX GRIDS...AS WELL. HIGHS TODAY AND
MONDAY WILL CONTINUE TO BE MOST DEPENDENT ON THE CLOUD COVER AND
CONVECTION...BUT GENERALLY THE 80 TO 85 DEGREE RANGE SHOULD SUFFICE.
AGAIN USED THE CONSSHORT AS A STARTING POINT FOR WINDS AND DEWPOINTS
THROUGH 24 HOURS...CONSALL THEREAFTER. AS FOR TEMPS...FAVORED THE
CONSALL FOR MAX AND MIN VALUES WITH A DIURNAL CURVE SET FROM OBS. AS
FOR POPS...HAVE ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH...
AND IN PARTICULAR ON...MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 320 AM EDT SUN AUG 11 2013
THIS FCST BEGINS WITH A RIDGE OVER THE ROCKIES AND A LARGE TROF OVER
THE ERN HALF OF THE CONUS. WITH THE TROF IN PLACE...EXPECT TEMPS TO
REMAIN BELOW SEASONAL AVERAGES. HOWEVER WITH THE NW FLOW ALOFT...
NUMEROUS SHORT WAVES WILL DIVE INTO THE ERN TROF AND BRING PERIODS
OF RAIN TO THE AREA AS THEY REINFORCE THE LONG WAVE TROF. WITH THE
AMPLIFIED PATTERN IN PLACE A SLOWER PROGRESSION OF VORT MAXES
PUSHING OVER THE RIDGE AND DIVING INTO THE TROF IS USUALLY A BETTER
CHOICE. THE ECMWF FITS THIS SCENARIO BETTER THAN THE OTHER
OPERATIONAL MODELS AND HAS BEEN UTILIZED TO TWEAK THE EXTENDED GRID
PROCEDURE.
FOR SENSIBLE WEATHER WE EXPECT A GOOD CHANCE OF RAIN MON NITE AND
TUE AS A RELATIVELY STRONG SHORT WAVE ROTATES THRU THE GREAT LAKES
AROUND THE ANCHORING LOW IN SRN CANADA. AS THIS SHORT WAVE CLEARS
TOWARDS NEW ENGLAND ON WED AND SFC HIGH PRESSURE CAN BUILD INTO THE
COMMONWEALTH...A SHORT PERIOD OF MOSTLY DRY WEATHER WILL SETTLE INTO
THE AREA. THE NEXT IN THE SERIES OF SHORT WAVES WILL DROP INTO THE
OHIO VALLEY THU NITE BRINGING MORE RAIN TO THE AREA AS A FRONT DROPS
SOUTH ON FRI. WE EXPECT THE FRONT TO STALL ALONG THE OHIO RIVER TO
KEEP THE THREAT OF RAIN IN THE EXTENDED FCST WELL INTO THE WEEKEND.
FOR TEMPERATURES...LOOK FOR HIGHS AROUND 80 ON TUE BEFORE THE RAIN
CAN DROP THE HIGHS INTO THE MID 70S FOR WED. THE THERMOMETER WILL
SLOWLY CLIMB AGAIN UNTIL REACHING VALUES AROUND 80 AGAIN FOR SAT.
LOW TEMPS WILL REMAIN IN THE 60S WITH MINOR FLUCTUATIONS EXCEPT FOR
WED NIGHT WHEN THE DRIER AIR AND MOSTLY CLEAR SKIES WILL ALLOW THE
MERCURY TO DIP INTO THE UPPER 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 730 AM EDT SUN AUG 11 2013
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ARE MAKING THEIR WAY
THROUGH SOUTHEAST KENTUCKY THIS MORNING. THE LOWER CIGS AND VSBY
WILL CONTINUE TO BE HIT AND MISS THROUGH THE MORNING. AN IMPROVEMENT
TO VFR SHOULD TAKE PLACE BY LATE MORNING. SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE AT JUST ABOUT ANY POINT THROUGH THE
DAY. TONIGHT...DO EXPECT SOME LOWER VIS AND CIGS DUE TO FOG AS THE
FROM FINALLY SINKS SOUTH OF THE TAF SITES. WINDS WILL BE LIGHT AND
VARIABLE DURING THE FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...GREIF
LONG TERM...DUSTY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 PM EDT SUN AUG 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 504 AM EDT SUN AUG 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WRLY FLOW THROUGH THE NRN
GREAT LAKES ON THE SRN FLANK OF A MID/UPPER LEVEL TROUGH EXTENDING
FROM HUDSON BAY TO NEW FOUNDLAND. A WELL-DEFINED UPSTREAM SHORTWAVE
TROUGH LOCATED NEAR THE NW CORNER OF MN SUPPORTED A BAND OF LIGHT
SHOWERS OVER N CNTRL MN. THE HEAVIER SHRA/TSRA REMAINED WELL TO THE
SOUTH FROM SE SD AND SW MN INTO NW IA ALONG THE 850 MB FRONT. AT THE
SFC...A WEAK TROUGH AHEAD OF THE MID LEVEL SHRTWV EXTENDED FROM NEAR
CYQT NRN MN. IR LOOP SHOWED MAINLY CLEAR SKIES OVER UPPER MI WITH
MID CLOUDS APPROACHING FROM NE MN.
TODAY...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE TIMING OF
THE SHRTWV ACROSS THE AREA BRINGING THIS FEATURE INTO CNTRL UPPER MI
AROUND 18Z AND QUICKLY TO LAKE HURON BY 00Z. THE COMBINATION OF THE
WEAK 700-300 MB QVECTOR CONV WITH THE SHRTWV AND LOW LEVEL CONV
ALONG THE TROUGH AND LAKE BREEZE BOUNDARIES SHOULD BE ENOUGH TO
SUPPORT AT LEAST SUPPORT ISOLD/SCT PCPN. MLCAPE VALUES TO AROUND 400
J/KG...PER NAM...WILL BE MARGINAL FOR TSRA BUT WITH THE ARRIVAL OF
THE SHRTWV DURING PEAK HEATING ISOLD TSRA WILL ALSO BE POSSIBLE.
TONIGHT...ANY SHRA/TSRA THAT DEVELOP DURING THE AFTERNOON WILL
DIMINISH WITH THE LOSS OF DAYTIME HEATING AND THE DEPARTURE OF THE
SHRTWV. A SLIGHT CHANCE FOR SHOWERS WAS MENTIONED AS ANOTHER WEAK
SHRTWV AND SFC MOVES THROUGH UPPER MI. EVEN THOUGH MOISTURE IS
LIMITED...SUCH WEAK DISTURBANCES IN THE BROAD CYCLONIC FLOW PATTERN
HAVE OFTEN MANAGED TO SUPPORT ISOLATED LIGHT SHOWERS.
HOWEVER...CONFIDENCE IN TIMING/POSITION OF ANY PCPN IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 316 AM EDT SUN AUG 11 2013
A QUIET WEEK IS IN THE MAKING FOR UPPER MICHIGAN AS HIGH PRESSURE
ANCHORS ITSELF OVER THE WESTERN GREAT LAKES. MOSTLY CLEAR SKIES
SHOULD BE THE RULE...THOUGH A SERIES OF WEAK SHORTWAVES COULD BE A
BIT PESKY WITH CLOUDS AROUND MID-WEEK. TEMPERATURES WILL SLOWLY WARM
TO NEAR NORMAL...WITH SEVERAL CHILLY NIGHTS
EXPECTED...ESPECIALLY TUESDAY NIGHT.
MONDAY AND MONDAY NIGHT...THE MAIN AXIS OF AN EASTERN CANADIAN
TROUGH WILL BE APPROACHING THE AREA AT THE START OF THE PERIOD.
MODEL GUIDANCE HAS STRUGGLED WITH MAINTAINING A STEADY APPROACH TO
THE STRUCTURE OF THIS TROUGH AXIS. THERE ARE SEVERAL DISTINCT AXES
EMBEDDED IN THE MAIN TROUGH...AND EACH SHOULD SWING THROUGH THE CWA
IN ABOUT 12 HOUR INTERVALS STARTING MONDAY MORNING. THE MAIN PLAYER
IN THIS SERIES IS CURRENTLY MOVING SSW INTO FAR NORTHWEST HUDSON BAY
AROUND THE WESTERN PERIPHERY OF AN IMPRESSIVE VORT MAX OVER CENTRAL
HUDSON BAY. BOTH ARE CLEARLY APPARENT IN WATER VAPOR SAT...SO SEE NO
REASON TO QUESTION MODEL PERFORMANCE WITH TIMING. THE TROUGH SHOULD
BE OVER WESTERN LAKE SUPERIOR BY 18Z MONDAY...AND EASTERN UPPER MI
AT 00Z TUESDAY. MID-LEVEL SUPPORT WILL BE PRESENT WITH MODEST H5
Q-VECTOR CONVERGENCE AND H7 FRONTOGENESIS. A SUBSIDENCE INVERSION
AROUND 600MB BEHIND SUNDAYS SYSTEM AND DRIER AIR BEHIND THE SFC
FRONT WILL LIMIT PCPN COVERAGE. LAKE BREEZE CONVERGENCE WILL ASSIST
PCPN DEVELOPMENT...BUT STABILIZING NW GRADIENT FLOW SHOULD CONFINE
BEST COVERAGE TO THE SOUTH-CENTRAL AND ALONG LAKE MI. THUNDER
POTENTIAL WILL BE MINIMAL WITH MUCAPE STRUGGLING TO REACH 500 J/KG
NORTH OF GRB. MOST OF THIS CAPE WILL BE BELOW THE 0C LEVEL...SO KEPT
THUNDER AT SLIGHT CHANCE OVER JUST THE SOUTH CENTRAL CWA.
MONDAY NIGHT AND TUESDAY...ANY PRECIP WILL DIMINISH WITH THE PASSAGE
OF AN ASSOCIATED SFC TROUGH AND LOSS OF DAYTIME HEATING MONDAY
EVENING. A SECOND MID-LEVEL WAVE CLOSER ASSOCIATED WITH THE MAIN
TROUGH AXIS WILL BE CROSSING THE CWA BY 12Z TUESDAY. THE NAM AND
ECMWF ARE A BIT SLOWER WITH THIS TROUGH AND ACTUALLY KICK OFF SOME
LIGHT SHOWER ACTIVITY ACROSS THE INTERIOR CENTRAL AND EAST TUESDAY
MORNING. WITH THE ATMOSPHERE QUITE DEPLETED OF MOISTURE AS NOTED BY
PWATS OF ONLY 0.7 INCHES...DO NOT EXPECT MUCH MORE THAN SOME
MID-LEVEL CLOUDINESS WITH MAYBE A FEW SPRINKLES. THIS DOES MAKE MIN
TEMPS FOR MONDAY NIGHT A LITTLE HARDER TO PIN DOWN. GIVEN THE
UNCERTAINTY IN MID-CLOUD COVER...OPTED NOT TO CHANGE MUCH AND LEAVE
TEMPS RANGING FROM THE MID 40S INTERIOR WEST TO THE LOW 50S ALONG
THE SHORE. QUITE A COOL TUESDAY WILL FOLLOW UNDER H8 TEMPS OF ONLY 4
TO 7C...COOLEST EAST. MIXING SHOULD REACH THE H8 LEVEL...SO TEMPS
ARE EXPECTED TO APPROACH 70F SOUTH CENTRAL. AN EXCELLENT MODIS SST
CAPTURE TODAY SHOWS LAKE TEMPS AROUND 50F IN THE NORTHERN OPEN
WATERS...AND MID 50S IN THE REMAINDER OF THE OPEN WATERS. SO EVEN
WITH A NORTH WIND...THE COASTAL AREAS SHOULD BE ABLE TO BREAK INTO
THE LOW 60S.
TUESDAY NIGHT THROUGH THURSDAY...SFC HIGH PRESSURE WILL SETTLE OVER
WESTERN UPPER MI TUESDAY NIGHT AS MID-LEVEL RIDGING ATTEMPTS TO
BUILD EASTWARD INTO THE UPPER MS VALLEY. LOW PWAT UNDER 0.5 INCHES
AND LIGHT WINDS WILL LEAD TO EXCELLENT RADIATIONAL COOLING.
CONTINUED USING A BLEND OF GUIDANCE THAT HAS PERFORMED WELL ON
SIMILAR NIGHTS OVER THE PAST FEW WEEKS. EXPECT 40S FOR ALL BUT THE
IMMEDIATE SHORE. SOME TYPICAL INTERIOR WEST COLD SPOTS COULD EVEN
SEE UPPER 30S.
A THIRD WAVE WILL SKIM THE NE CWA WEDNESDAY MORNING. LITTLE MOISTURE
AND MINIMAL LIFT WILL BRING ONLY SCATTERED MID-CLOUDS. ANOTHER WAVE
WILL FOLLOW THE SAME TRACK ON THURSDAY...BUT WILL SUCCUMB TO THE
SAME LIMITING FACTORS. CLOUDINESS SHOULD BE A LITTLE MORE AS LIMITED
MOISTURE RETURN BEGINS ON THE BACKSIDE THE SFC RIDGE.
FRIDAY AND SATURDAY...MODEL GUIDANCE IS SHOWING A TROUGH DROPPING SE
OVER NORTHERN ONTARIO LATE FRIDAY INTO SATURDAY. THOUGH GUIDANCE IS
SHOWING MORE CONSISTENCY...WILL CONTINUE CONSENSUS APPROACH TO
PRECIP CHANCES FOR NOW...WHICH SHOULD BE LIMITED TO SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 131 PM EDT SUN AUG 11 2013
EXPECT VFR CONDITIONS THIS FCST PERIOD AT ALL THREE TAF SITES. A
PASSING DISTURBANCE MAY CAUSE SOME -SHRA THIS AFTN IN THE PRESENCE
OF DAYTIME HEATING AT SAW AND PERHAPS IWD...BUT CONFIDENCE IS TOO LOW
TO INCLUDE MORE THAN VCSH IN THE TAFS. ANY -SHRA WILL END BY
SUNSET WITH THE ONSET OF NOCTURNAL COOLING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 504 AM EDT SUN AUG 11 2013
A SERIES OF WEAK TROUGHS WILL MOVE THROUGH LAKE SUPERIOR THROUGH
MONDAY. HOWEVER...WINDS ARE EXPECTED TO REMAIN LESS THAN 20 KNOTS.
HIGH PRESSURE WILL RESUME CONTROL OF THE WRN GREAT LAKES TUESDAY
THROUGH THE END OF THE WEEK TO KEEP WINDS GENERALLY LIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1230 PM CDT SUN AUG 11 2013
.AVIATION...18Z TAF ISSUANCE...
GENERALLY VFR CIGS THROUGH THIS AFTERNOON WITH ISOLATED RAIN
SHOWERS AND EVEN A FEW VERY ISOLATED T-STORMS. VSBYS COULD DROP TO
MVFR TEMPORARILY IN THE BRIEF HEAVY SHOWERS. WINDS WILL REMAIN
LIGHT FROM THE N/NW...EXCEPT AROUND THE PERIPHERY OF LAKE
SUPERIOR...WITH A LIGHT LAKE BREEZE. COULD SEE PATCHY FOG DEVELOP
LATE TONIGHT WHERE MID/HIGH CLOUDS CLEAR OFF.
&&
.PREV DISCUSSION... /ISSUED 1027 AM CDT SUN AUG 11 2013/
UPDATE...
THE FOCUS ON THIS UPDATE IS ON CLOUD COVER AND PCPN TRENDS THROUGH
THIS EVENING. THE MODELS ARE SUGGESTING THAT SCATTERED/BROKEN
CUMULUS CLOUDS WILL DEVELOP IN OUR COOL WNW FLOW EARLY THIS
AFTERNOON WHEN WE GET CLOSER TO PEAK HEATING AND AFTER SOME OF THE
REMAINING MID TO HIGH LEVEL CLOUDS FROM THIS MORNING DISSIPATE OR
MOVE OUT OF THE FORECAST AREA. THE HRRR AND SREF...INCLUDING SOME
OTHER MODELS...ARE SUGGESTING THERE MAY BE SOME SHOWERS AND/OR
SPRINKLES AMIDST THE SCT/BKN CUMULUS. THEREFORE...I ADDED SOME
MENTION OF SHOWERS OVER MOST OF THE NORTHLAND FOR THIS AFTERNOON.
THERE MAY ALSO BE SOME WEAK THUNDERSHOWERS.
AVIATION...12Z TAF ISSUANCE...
UPPER LEVEL SYSTEM WILL CROSS CWA TODAY WITH SHOWERS POSSIBLE AT
TIMES. CEILINGS SHOULD REMAIN VFR EXCEPT NEAR KINL WHERE MVFR
MAY DEVELOP THIS MORNING AND INTO THE EARLY AFTERNOON. SFC HIGH
BUILDS INTO REGION OVERNIGHT HOWEVER MAY SEE LINGERING VFR
CEILINGS NEAR 5K TO 7K FEET ACROSS SOME TERMINALS.
PREV DISCUSSION... /ISSUED 703 AM CDT SUN AUG 11 2013/
UPDATE....
SHOWERS ARE SLIGHTLY MORE NUMEROUS THAN THOUGHT SO MADE SOME
SLIGHT ADJUSTMENTS TO RAISE POPS SLIGHTLY.
PREV DISCUSSION... /ISSUED 330 AM CDT SUN AUG 11 2013/
SHORT TERM...
THE UPPER LEVEL LOW PRESSURE TROUGH CENTERED OVR EASTERN CANADA AND
STRETCHING ACROSS THE GREAT LAKES WILL PRODUCE SOME MORE SHOWERS
TODAY. A COUPLE MORE S/WVS WILL ROTATE THROUGH THE TROF TODAY.
CURRENT WV LOOP DEPICTS THE S/WV INTO NWRN MN.. AND HAS RESULTED
IN SOME VERY LIGHT SHOWERS ACROSS NORTHERN MN. THIS WAVE WILL
ROTATE SEWRD ACROSS THE CWA...AND HAVE GIVEN SMALL POPS FOR THE
REGION. EXPECT SHOWERS TO BE MAINLY THIS MORNING IN THE FAR
NORTH...AND NOT BEGIN TIL MID TO LATE MORNING IN NWRN WI. HAVE
INTRODUCED SOME THUNDER LATER TODAY WITH FAIRLY STEEP LOW LEVEL
LAPSE RATES LATER THIS MORNING AND AFTERNOON AND LI`S DOWN TO -2.
EXTENDED...MONDAY THROUGH SATURDAY...
AN UNUSUALLY STRONG MID LVL VORTEX OVER CTRL ONTARIO WILL PUSH A SFC
COLD FRONT ACROSS THE REGION MONDAY. A CYCLONICALLY CURVED FLOW
COMBINED WITH SUFFICIENT DEEP LAYER MOISTURE WILL CREATE SHOWER
POTENTIAL OVER THE NRN/ERN PARTS OF THE CWA. FOR THE REMAINDER OF
THE WEEK THE ANOMALOUS ONTARIO MID LVL TROF WILL MOVE EAST.
INCREASING RIDGING ALOFT WILL ALLOW A LARGE SFC HIGH TO EXPAND
FROM THE SRN PLAINS OF CANADA INTO THE LOWER GT LAKES. A PERIOD OF
QUIET WX IS EXPECTED TUES THROUGH THUR AS SUBSIDENCE SFC/ALOFT
DOMINATES MOST OF THE REGION. THE ONLY POSSIBLE EXCEPTION WOULD BE
OVER ERN ARROWHEAD CLOSER TO EASTERN VORTEX. CONFIDENCE IN FCST
DECREASES BY FRIDAY AS GEM/GFS/ECMWF DISAGREE ON MID LVL FLOW
EVOLUTION. AS WAS THE CASE IN PREVIOUS GRIDS/FCST WILL CARRY SOME
LOW POPS BEGINNING FRIDAY...AND INTO THE WEEKEND. THE CONSENSUS IS
THAT A WARMING TREND IS APPEARING MORE LIKELY FOR THE WEEKEND AS
UPPER HEIGHTS BUILD AND 925/85 TEMP VALUES RISE ABOVE WHAT WE HAVE
EXPERIENCED IN A WHILE. 85H MSTR TRANSPORT AMONG THE MED RANGE MDLS
SUGGESTS ENOUGH MOISTURE WILL BE AVAILABLE FOR CONVECTION
SAT/SUNDAY. OVERALL SYNOPTIC SCALE PATTERN THIS WEEKEND WOULD
SUGGEST INCREASING POSSIBILITY OF MCS GENERATION OVER SRN
SASK/MAN...MOVING SE TOWARDS CWA. TOO MANY UNCERTAINTIES TO
HIGHLIGHT MAGNITUDE/AREAL COVERAGE OF POTENTIAL STRONG/SVR STORMS.
TEMPS WILL AVERAGE BLO CLIMO MOST OF THE WEEK AND THEN NEAR/ABOVE
CLIMO FOR THE WEEKEND.
&&
.POINT TEMPS/POPS...
DLH 55 72 49 69 / 10 10 0 0
INL 49 71 45 70 / 20 20 0 0
BRD 51 76 50 74 / 10 10 0 0
HYR 52 74 47 72 / 10 10 0 10
ASX 53 71 48 68 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
313 PM CDT Sun Aug 11 2013
.SHORT TERM: (Through Late Tonight)
Issued at 313 PM CDT Sun Aug 11 2013
Low level flow is turning back around to the south across southern
and central Missouri. Already seeing cumulus spread up to near
California Missouri and points west-northwest. A weak low level jet
develops tonight which produces some decent moisture convergence at
850mb primarily over southern portions of the CWFA. It doesn`t look
like the forcing is strong enough to produce very widespread or
organized convection, however the RUC is showing about 900 J/KG CAPE
in the region of moisture convergence, and the CAPE is fairly tall
extending up to 35,000ft. Certainly can`t rule out isolated-widely
scattered showers and thunderstorms over southeast Missouri and
possibly parts of east central and central Missouri as well, though
the lift drops off further north. Lows will be warmer tonight due
to the increasing cloud cover and southerly flow.
Carney
.LONG TERM: (Monday through Next Sunday)
Issued at 313 PM CDT Sun Aug 11 2013
Main concern continues to be thunderstorms chances early this week.
Scattered thunderstorms may be ongoing over the eastern Ozarks into
southern Illinois early Monday on the nose of a veering low level
jet. Better chance of storms will be focused along a cold front
that enters the northern CWFA early in the day and moves slowly
south through the day. Atmosphere will become increasingly
unstable along and ahead of the front with MLCAPEs around 1,000
J/kg with some weak CIN. This should be enough to generate
scattered thunderstorms given weak large scale ascent from a
passing shortwave. There may be a few strong storms that could
producing some gusty winds given the relatively dry low-mid levels
seen on the forecast soundings, though deep layer shear of only
25-30 knots will limit overall severe threat.
Not too many changes to previous thinking that rain chances will
diminish from north to south on Monday Night and Tuesday as the
front slowly moves south into the Mid South. Still have a dry
forecast going mid to late week as an impressive surface ridge
creeps southward through the area. Easterly low level flow and
850mb temperatures around 10C should keep temperatures below mid
August normals from Wednesday into Friday. Latest runs of the
GFS/ECMWF do agree that an upper trough will deepen over Missouri
and Illinois by Saturday. There will be Gulf moisture drawn
northward ahead of this trough, though any rain looks like it will
stay just south and east of us next weekend. 850mb temperatures
will warm into the mid-teens causing temperatures to climb closer
to normal by next weekend.
Britt
&&
.AVIATION: (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1236 PM CDT Sun Aug 11 2013
VFR flight conditions and light southeast flow will prevail for
the rest of the day into tonight across the region. There is a
small chance that some showers and possibly a thunderstorm could
develop across the eastern Ozarks before sunset. A weak low level
jet will develop late tonight over southern Missouri which may be
enough to develop isolated showers or thunderstorms along and
south of the I-70 corridor, but chances of precip appear to be
very low at this time so have left mention out of terminal
forecasts.
Specifics for KSTL:
VFR flight conditions and light southeast flow will continue to
prevail at Lambert through tonight. There is a slight chance that
some isolated showers or thunderstorms could develop south of the
terminal, around sunrise which could affect Lambert. However,
chances are so small right now that I`ve opted to leave mention of
precip out of the TAF at this time. A cold front will approach the
terminal from the north late Monday. Additional thunderstorm
development is possible ahead of the front Monday afternoon,
however am leaving mention out until we get a better handle on
timing and potential coverage of storms.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
308 PM CDT SUN AUG 11 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 245 PM CDT SUN AUG 11 2013
A SURFACE TROUGH OF LOW PRESSURE ACROSS NORTHERN NEBRASKA THIS
AFTERNOON IS EXPECTED TO PROVIDE ENOUGH CONVERGENCE FOR THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE OUTLOOK
AREA BY LATE AFTERNOON AS THE CAP BEGINS TO WEAKEN. WHILE THE
INSTABILITY VALUES REMAIN HIGH...ON THE ORDER OF 3000 J/KG OF MU
CAPE...THE WIND SHEAR VALUES ARE VERY WEAK...AND PRIMARY CONCERN
WITH THESE STORMS WILL BE THE POTENTIAL FOR LARGE HAIL. MODELED
SOUNDINGS ALSO INDICATE AN INVERTED V ATMOSPHERIC PROFILE FOR THE
LATE AFTERNOON AND EARLY EVENING HOURS...SO STRONG WIND GUSTS MAY
ALSO BE A CONCERN. NOT SURPRISINGLY...THE ENTIRE OUTLOOK ARE
REMAINS IN A SLIGHT RISK FOR SEVERE WEATHER FROM SPC...WITH LARGE
HAIL AND WINDS BEING THE PRIMARY CONCERN.
SOME OF THE LATEST MODEL RUNS ARE INDICATING THE CONVECTION
CURRENTLY DEVELOPING ACROSS THE HIGH PLAINS AND ASSOCIATED WITH A
PASSING SHORTWAVE IN WV IMAGERY...WILL EVENTUALLY MERGE WITH
CONVECTION IN PROXIMITY OF THE SURFACE TROUGH...WHICH COULD RESULT
IN AN ACTIVE EVENING...PRECIPITATION WISE...ACROSS THE LOCAL
AREA. THE 12Z WRF APPEARS TO BE THE MOST AGGRESSIVE WITH THE
SCENARIO...AND THE 18Z RAP ALSO HINTING AT A SOLUTION SIMILAR TO
THIS...SO FELT CONFIDENT ENOUGH TO INCREASE POPS THROUGH THE EARLY
EVENING HOURS INTO THE 50 PERCENT RANGE ACROSS MOST OF THE AREA.
OTHERWISE...WITH THE SLOW MOVEMENT OF ANY STORMS THAT DO
DEVELOP...HEAVY RAINFALL WILL ALSO BE A CONCERN...AND CONTINUED
WITH THE POTENTIAL FOR VERY LOCALIZED FLOODING THIS EVENING AND
OVERNIGHT.
FOR MONDAY...EXPECT A MOSTLY DRY START TO THE DAY...WITH
INCREASING CHANCES FOR PRECIPITATION BY AFTERNOON AS WE COULD SEE
SOME CONVECTION REDEVELOP IN THE VICINITY OF THE STALLED OUT
FRONT/TROUGH WHICH WILL THEN BE ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 245 PM CDT SUN AUG 11 2013
COOLER THAN NORMAL SUMMER WEATHER WILL SETTLE IN ACROSS OUR REGION
FOR MUCH OF THE WORKWEEK IN A NORTHWEST FLOW REGIME ACROSS THE
CENTRAL PLAINS. WARMER AIR WILL RESIDE TO THE WEST FM THE DESERT SW
NORTH ACROSS THE ROCKIES...WHILE TO THE EAST...A TROUGH NEAR THE
HUDSON BAY WILL DEEPEN AND TRANSLATE ACROSS THE EASTERN CONUS.
COOLER AIR WILL BACK IN ACROSS THE PLAINS FM THE UPPER MIDWEST AND A
1022ISH MB SFC HIGH WILL BUILD SOUTH FM THIS AREA ONTO THE PLAINS...AND
WILL REINFORCE THE COOLER AIRMASS UNTIL AROUND THE THURSDAY TIME
FRAME. BY THE END OF THE WEEK AND HEADING INTO THE WEEKEND...THE
SFC RIDGE AXIS SLIDES EAST AND THE UPPER RIDGE OVER THE ROCKIES WILL
BEGINS TO BUILD TOWARDS THE PLAINS AND TEMPERATURES WILL BEGIN TO
MODERATE CLOSER TO SEASONAL NORMALS.
FOR CONVECTIVE POTENTIAL...CANNOT RULE OUT TSTM CHANCES DURING THIS
TIME FRAME...WITH DEVELOPMENT DEPENDENT UPON BOUNDARY LOCATIONS AND
TIMING OF WAVES. ON MONDAY...A FEW STORMS MAY LINGER IN THE
MORNING...WITH REDEVELOPMENT POSSIBLE DURING THE DAY ALONG A BACK
DOOR COOL FRONTAL BOUNDARY AND ALSO TO THE WEST IN AN UPSLOPE FLOW
REGIME. A STRONG TO SEVERE STORM IS POSSIBLE IN SUFFICIENT
INSTABILITY...BUT SHEAR REMAINS WEAK. THE BETTER PCPN CHCS BEGIN TO
FOCUS TO OUR WEST THROUGH MID WEEK...WITH SOME POTENTIAL FOR HIGH
PLAINS CONVECTION TO MIGRATE EAST TOWARDS OUR WESTERN CWA. AS
PATTERN CONTINUES TO AMPLIFY...FOCUS TURNS MORE TO TIMING OF WAVES
TOPPING RIDGE AND CROSSING THE PLAINS...WITH HIT OR MISS CHCS FOR
THE OUTER PERIODS...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE
POPS.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1230 PM CDT SUN AUG 11 2013
VFR CONDITIONS WILL PREVAIL AT KGRI FOR THE NEXT SEVERAL HOURS AS
VARIABLY CLOUDY SKIES STREAM ACROSS THE REGION. GUSTY SOUTHERLY
WINDS WILL ALSO CONTINUE THROUGH ABOUT 23Z...WHEN THE SURFACE
TROUGH ACROSS NORTHERN NEBRASKA SAGS CLOSER TO THE TERMINAL. THIS
TROUGH SHOULD PROVIDE ENOUGH CONVERGENCE FOR THE DEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE EVENING HOURS...AND
INTRODUCED A TEMPO GROUP FOR MVFR VSBYS AND CIGS FROM
11/23Z-12/02Z...AS THIS BOUNDARY SAGS SOUTH. OTHERWISE...WINDS
WILL BE LIGHT AND VARIABLE TOWARDS MORNING...WITH VFR CONDITIONS
AND LIGHT NORTHEASTERLY WINDS EXPECTED DURING THE DAY MONDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...FAY
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1206 PM CDT SUN AUG 11 2013
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
POTENTIAL FOR TSRA THROUGH THE EVENING AND POTENTIAL FOR IFR
CONDITIONS LATER TONIGHT ARE THE MAIN AVIATION CONCERNS. EXPECT
SCATTERED STORMS TO DEVELOP ACROSS EASTERN NEBRASKA THIS AFTN
AND CONTINUE THIS EVENING. UNCERTAINTY EXITS AS TO HOW LONG STORMS
WILL BE AROUND BUT COVERAGE SHOULD DECREASE SOME BY AROUND SUNSET.
WINDS WILL SHIFT TO THE NORTH INITIALLY THEN BECOME NORTHEAST.
SHALLOW COOL MOIST AIRMASS BEHIND THE FRONT WILL BE FAVORABLE FOR
SOME FOG AND LOW CLOUDS. DID MENTION IFR CEILINGS AND VSBYS AT
KOFK...AND WILL NEED TO MONITOR FOR POSSIBLE INCLUSION FOR KOMA
AND KLNK.
MILLER
&&
.PREV DISCUSSION... /ISSUED 246 AM CDT SUN AUG 11 2013/
DISCUSSION...
PRECIPITATION CHANCES THROUGH MONDAY NIGHT PRIMARY FORECAST FOCUS
AS A WEAK FRONT SAGS ACROSS THE FA LATE TODAY INTO MONDAY.
EARLY MORNING SATELLITE/RADAR SHOWED A VORT MAX/TROUGH MOVG SE
ACROSS NWRN MN WITH SEVERAL CONVECTIVE CLUSTERS TO THE SW ON NOSE
OF LOW LEVEL JET/WARM ADVECTION OVR SD INTO NW IA. ALTHOUGH
VARIOUS SHORT TERM MODELS LIKE HOP WRF/RAP KEPT PRECIP MOSTLY NE
OF FA THIS AM ...4KM WRF AND HRRR DID TRY TO DEVELOP SOME OVER NRN
ZONES THIS MORNING. SO SOME SMALL POPS WILL BE MAINTAINED WITH
LAST MINUTE ADJUSTMENTS POSSIBLE BASED ON TRENDS BEFORE ISSUANCE.
OTHERWISE WITH BOUNDARY FORECAST TO SLOWLY SAG INTO NRN ZONES THIS
AFTN...HEATING SHOULD HELP REGENERATE CONVECTION LATER THIS
AFTERNOON...ALTHOUGH 4KM WHICH DEVELOPED IT MOSTLY S OF HIGHWAY 30
APPEARED TOO FAR S. COVERAGE THIS AFTERNOON AND EVOLUTION TONIGHT
IN DOUBT AS H5-H7 QG FORCING WAS NEGLIGIBLE WITH DIFFERENTIAL
HEATING ACROSS BOUNDARY THIS AFTN THEN SYSTEM MOTION FOR INFLOW
WOULD BE PRIMARY DRIVERS AS LOW LEVEL JET WEAKENS FAIRLY
SUBSTANTIALLY THROUGH TONIGHT. THUS KEPT POPS IN CHC CATEGORY FOR
NOW FOR LATE AFTN THROUGH EARLY TONIGHT. WITH THIS LACK OF LOW
LEVEL JET TONIGHT CONFIDENCE NOT VERY HIGH ON HOW MUCH COVERAGE
WILL EXIST AFTER 06Z OVER FA SO GENERALLY TRENDED POPS DOWN AFTER
THAT TIME. WITH MODEL AGREEMENT IN H85 THERMAL RIDGE POKING UP
TOWARD WCNTRL ZONES THIS AFTN BOOSTED HIGHS A BIT...WHICH WERE
STILL BELOW WARMER NAM WHICH ONE OF THESE DAYS MAY ACTUALLY TURN
OUT BETTER IF SWRLY SFC WINDS CAN BE MAINTAINED LONG ENOUGH.
IF CONVECTION TONIGHT PUSHES EFFECTIVE BOUNDARY SOUTH OF FA BY
MONDAY AFTN FURTHER CONVECTIVE DEVELOPMENT COULD BE LIMITED OVER
OUR AREA AND TRENDS WILL NEED MONITORING. HOWEVER...FOR NOW LEFT
IN CHC POPS S WITH SLIGHTS N THROUGH NORFOLK OR SO AS BOUNDARY
PUSH WAS MODEST AT BEST. ALTHOUGH H85 TEMPS DON/T COOL SIGNIFICANTLY
YET ON MONDAY...TEMPERATURES SHOULD BE SOMEWHAT COOLER MOST
AREAS...ESPECIALLY IF DEBRIS CLOUDS CAN BE MAINTAINED. SOME POPS
WERE KEPT THEN MONDAY NIGHT SW 2/3RDS OR SO IN CASE ANY UPSTREAM
CONVECTION WOULD HOLD TOGETHER...ALTHOUGH MUST SAY NOT REALLY SOLD
ON THAT IDEA.
IN FACT...EVEN THOUGH SOME SMALL POPS WERE ALSO MAINTAINED TO INTO
MIDWEEK BEFORE SPREADING E TOWARD FRIDAY...APPEARS BULK OF ANY
ACTIVITY COULD REMAIN TO OUR WEST THROUGH LATE WEEK...ESPECIALLY
PER 00Z ECMWF. THAT MODEL HAS REMAINED FAIRLY CONSISTENT IN THAT
REGARD. PLEASANT TEMPERATURES LOOK IN STORE FOR FORECAST AREA
MUCH OF NEXT WEEK BEFORE MODERATING LATE AS NORTHWESTERLY FLOW
SENDS CANADIAN HIGH PRESSURE DOWN MISSISSIPPI VALLEY. THIS HAS
BEEN ONE OF OUR SAVING GRACES THIS SUMMER AS SIGNIFICANTS RAINS
HAVE BEEN SPOTTY AND MANY AREAS ARE RUNNING MODERATE PRECIP
DEFICITS SINCE JUNE.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1139 AM MDT SUN AUG 11 2013
.AVIATION...
18Z TAF CYCLE
VFR CONDITIONS FORECAST AT AREA TERMINALS OUTSIDE OF SCATTERED
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. MVFR
CIGS/VSBYS LIKELY WITH THUNDERSTORMS LATER TODAY...WITH SOME
SHORT-LIVED IFR CONDITIONS POSSIBLE. TERMINALS MOST LIKELY TO BE
IMPACTED INCLUDE KGUP...KSAF AND KLVS. IMPACTS TO KABQ WILL BE
LATER IF AT ALL...BETWEEN 00-03Z.
11
&&
.PREV DISCUSSION...927 AM MDT SUN AUG 11 2013...
UPDATED MORNING PRECIPITATION CHANCES AND SKY COVER FOR NORTH-CENTRAL
AND WESTERN AREAS. RAIN COOLED/STABLE ATMOSPHERE IN PLACE THIS MORNING
OVER THESE AREAS SO NOT EXPECTING MUCH IN THE WAY OF CLOUDS AND/OR
SHOWERS. ALSO TRENDED DOWN POPS FOR THE RG VALLEY AND SAN JUAN RIVER
VALLEY FOR THIS AFTERNOON WITH MOST ACTIVITY HOLDING OFF UNTIL EARLY
EVENING AFTER SFC HEATING WORKS AWAY AT SUBSIDENCE INVERSION BEHIND
DEPARTING WAVE/MCV.
33
.PREV DISCUSSION...330 AM MDT SUN AUG 11 2013...
LARGE AREA OF RAIN COVERING MUCH OF THE SOUTH CENTRAL WITH SHOWERS
AND STORMS MORE ACTIVE SOUTHEAST/EAST CENTRAL...AND SOME OF THESE
ARE HEAVY RAINERS. THE ENTIRE MESS IS MOVING NORTHEAST ATTM.
FORECAST SURFACE PATTERN FOR THE CWA LACKING THE LOW LEVEL EASTERLY
FLOW OF FRIDAY AND SATURDAY. WINDS AND THEREFORE CONVECTION MAY MOVE
A BIT FASTER TODAY WITH SOME INDICATION THERE/S AN UPPER
PERTURBATION OR TWO TO PASS THROUGH THE CENTRAL PORTION OF THE
STATE...AND TPW IMAGERY SHOWS AN INCH OR MORE OVER MOST OF THE
SOUTHEAST THREE QUARTERS OF THE STATE...ALTHOUGH WATER VAPOR IMAGERY
SUGGESTS SOME DRIER AIR ALOFT COULD START TO WORK INTO THE WEST.
CONCERN THAT AFTER THIS MORNINGS ACTIVITY DIMINISHES THERE MAY BE A
BRIEF LULL BEFORE CONVECTION GETS GOING AGAIN...WHICH HRRR INDICATES
IT MAY NOT REGENERATE TO CURRENT LEVELS. THEREFORE WILL ALLOW THE
FFA TO RUN ITS COURSE AND EXPIRE AT 6AM. HOWEVER...ANY STORM COULD
STILL PRODUCE LOCALLY HEAVY RAINFALL WHICH COULD LEAD TO FLASH
FLOODING...AND WILL HAVE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
MENTIONED IN THE ZFP.
MONDAY NOT LOOKING AS DRY AS PREVIOUSLY THOUGHT WITH PLENTY OF
RESIDUAL MOISTURE UNDERNEATH THE BUILDING RIDGE. LATEST NAM BRINGING
IN THE BOUNDARY INTO THE NORTH/NORTHEAST MONDAY EVENING AND IT
REACHES THE CENTRAL MT CHAIN TUESDAY AFTERNOON/EVENING. HAVE MADE
SOME ADJUSTMENTS TO THE POP/WX GRIDS TO ACCOUNT FOR THIS. LOW LEVEL
EASTERLY FLOW PERSISTS WEDNESDAY THEN WEAKENS SOME INTO THURSDAY AS
THE UPPER RIDGE AXIS STAYS TO OUR WEST AND NORTHWEST. OVERALL
INDICATIONS ARE THE UPCOMING WORK WEEK AND INTO NEXT WEEKEND MAY BE
MORE ACTIVE AND WETTER ESPECIALLY FOR PORTIONS OF THE NORTH AND
EAST.
.FIRE WEATHER...
EXCELLENT HUMIDITY RECOVERIES AGAIN THIS MORNING AS SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS THE LOWER RIO GRANDE VALLEY EASTWARD
ACROSS THE EAST CENTRAL PLAINS. THESE SHOWERS AND THUNDERSTORMS WILL
LINGER INTO THE MORNING HOURS BEFORE DIMINISHING. THIS AFTERNOONS
CROP OF THUNDERSTORMS IS EXPECTED TO GET A LATER START THAN
YESTERDAY...BUT RESIDUAL MOISTURE SHOULD BE ENOUGH FOR STORMS TO
DEVELOP ACROSS THE HIGH TERRAIN. STORM MOTIONS WILL BE FROM WEST TO
EAST AND A BIT FASTER THAN YESTERDAY. NONETHELESS...LOCALLY HEAVY
RAIN AND FLOODING WILL REMAIN A CONCERN. OTHERWISE... HUMIDITIES
WILL BE VERY CLOSE TO YESTERDAYS READINGS...WITH HIGH TEMPERATURES
REMAINING SLIGHTLY BELOW NORMAL.
THE MONSOON PLUME WILL BE CUT OFF MONDAY AS THE UPPER HIGH SHIFTS
WESTWARD. RECYCLE MODE IN THE FORM OF SHOWERS AND THUNDERSTORMS
WILL BE IN FULL SWING...THOUGH COVERAGE SHOULD START TO TREND
DOWNWARD SOMEWHAT. TEMPS SHOULD ALSO BE A FEW DEGREES WARMER THAN
TODAY. BY TUESDAY...THE UPPER HIGH WILL BE ELONGATED OVER SOUTHERN
NM...BUT NORTHWEST FLOW ALOFT OVER NORTHEAST NM WILL HELP DRIVE A
BACK DOOR COLD FRONT INTO THE REGION. STORMS ON TUESDAY WILL FAVOR
NE NM NEAR THE FRONT AS DRIER AIR WILL CONTINUE TO MOVE IN FROM THE
WEST ELSEWHERE. HUMIDITIES WILL TREND DOWNWARD...MAINLY ACROSS
WESTERN AND CENTRAL AREAS...MONDAY AND TUESDAY.
THE FRONT WILL SAG FURTHER SOUTH ACROSS THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...AS THE UPPER HIGH FOCUSES OVER THE BOOTHEEL OF NM. WITH
ABUNDANT LOW LEVEL MOISTURE MOVING IN BEHIND THE FRONT...NOT ONLY
WILL HUMIDITIES GET A BOOST...BUT CHANCES FOR THUNDERSTORMS WILL
INCREASE. ELSEWHERE....STORMS WILL CONTINUE TO RELY ON RECYCLED
MOISTURE.
NOT MUCH CHANGE LATE IN THE WEEK...THE UPPER HIGH WILL REMAIN OVER
THE BOOTHEEL REGION...AND DRY AIR ALOFT WILL CONTINUE TO FILTER INTO
THE STATE AROUND THE HIGH. EASTERN PLAINS WILL REMAIN THE FAVORED
AREA FOR STORMS...THOUGH HIGH TERRAIN STORMS WILL REMAIN POSSIBLE
WITH RECYCLED MOISTURE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
641 PM EDT SUN AUG 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH THIS EVENING. A
STORM SYSTEM AND ASSOCIATED COLD FRONT WILL APPROACH THE NORTH
COUNTRY LATE MONDAY AFTERNOON WITH SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED INTO TUESDAY. THE FRONT WILL SLOWLY PUSH
EASTWARD TUESDAY NIGHT USHERING IN A COOL AND DRY CANADIAN
AIRMASS. TEMPERATURES THROUGH THE REST OF THE WORKWEEK WILL BE A
FEW DEGREES BELOW NORMAL FOR MID-AUGUST.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
AS OF 641 PM EDT SUNDAY...LATE-AFTERNOON VISIBLE SATELLITE TRENDS
SHOW DIURNALLY-DRIVEN FAIR WEATHER STRATOCUMULUS QUICKLY ERODING.
LOOKING UPSTREAM HOWEVER...A BROAD SWATH OF BROKEN TO OVERCAST
4000-6000 FT CEILINGS IS QUICKLY MOVING INTO WESTERN NEW YORK AND
THE NORTHERN SHORE OF LAKE ONTARIO. THESE CLOUDS ARE EMBEDDED IN
FAST ZONAL FLOW ALOFT /40-50KTS AT 500 MB PER RAP MODEL ANALYSES/.
THESE WILL MOVE WEST-TO- EAST OVER THE SOUTHERN SAINT LAWRENCE
VALLEY...NORTHERN ADIRONDACKS...AND INTO SOUTHERN VERMONT THROUGH
MIDNIGHT. SO I HAVE INCREASED CLOUD COVER THROUGH MIDNIGHT IN
THESE AREAS...THOUGH QUICKLY CLEARING AS PER SATELLITE TRENDS
ACROSS THE NORTHERN LAKES. I ALSO ADJUSTED LOW TEMPERATURES UP A
DEGREE OR SO GIVEN THE GREATER COVERAGE IN CLOUDS. ASIDE FROM
THESE MINOR ADJUSTMENTS THE GOING FORECAST LOOKS GOOD AT THIS
POINT WITH NO OTHER CHANGES MADE.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 337 PM EDT SUNDAY...INCREASING CLOUDS EXPECTED ON MONDAY
AHEAD OF AN APPROACHING UPPER LEVEL TROUGH MOVING SOUTHEASTWARD
OUT OF NORTHERN ONTARIO. ITS ASSOCIATED SFC COLD FRONT WILL BE
SLOW TO MOVE SOUTHEASTWARD WITH 500 MB FLOW BEING NEARLY PARALLEL
TO THE SFC FRONT. SO HAVE SLOWED THE ONSET OF SLIGHT CHANCE
PRECIPITATION PROBABILITIES INTO THE SAINT LAWRENCE VALLEY UNTIL
AFTER 18Z MONDAY WITH THAT IDEA IN MIND...AND A SLOW EASTWARD
INCREASE THROUGH THE EVENING UP TO HIGH CHANCE/LOW LIKELY BY 12Z
TUESDAY. HIGHS MONDAY IN THE 70S WITH A FEW LOW 80S POSSIBLE IN
THE CHAMPLAIN VALLEY & LOWS IN THE 50S TO LOW 60S.
THE FRONT WILL BE SLOWLY PUSHING SOUTHEASTWARD ACROSS THE REGION ON
TUESDAY. THINK THAT THUNDER IS POSSIBLE BUT MAINLY FROM THE
CHAMPLAIN VALLEY SOUTH AND EAST. IN FACT THE COMBINATION OF
STRONGEST DYNAMICS AS WELL AS SOME MODEST INSTABILITY /CAPE VALUES
800-1000 J/KG/ SUGGESTS THE BEST CHANCE FOR THUNDER WILL BE ACROSS
CENTRAL AND SOUTHERN VERMONT. WHILE LIKELY POPS ARE INDICATED FOR
MOST OF THE AREA ON TUESDAY...HAVE INCLUDED CHANCE THUNDER FOR
CENTRAL AND SOUTHERN VERMONT WITH SLIGHT CHANCE THUNDER FOR THE REST
OF VERMONT FOR TUESDAY AFTERNOON. FRONT LOOKS TO PUSH THROUGH THE
AREA AFTER 00Z WEDNESDAY WITH SOME LINGERING SHOWERS UNTIL THE FRONT
CLEARS FOR EASTERN VERMONT. GENERALLY THINK IT`S A LIGHT TO MODERATE
QPF EVENT WITH 36 HR QPF TOTALS FROM .25" TO .50".
STRONG COLD AIR ADVECTION BEHIND THE FRONT ON TUESDAY NIGHT WITH 850
TEMPERATURES DROPPING TO +4C TO +6C SHOULD ALLOW FOR LOW
TEMPERATURES TO DROP INTO THE 40S TO LOW 50S. DUE TO SOME QUESTION
AS TO HOW MUCH CLOUD COVER WILL BE LEFT OVER HAVE OPTED TO LEAN
SLIGHTLY WARMER. IF SKIES CAN CLEAR OUT FURTHER IT MAY BE A FEW
DEGREES COOLER THAN SHOWN HOWEVER.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 337 PM EDT SUNDAY...NORTHWEST FLOW ALOFT DEVELOPS ON
BACKSIDE OF UPPER TROUGH ON WEDNESDAY. DRIER WEATHER IS
EXPECTED...BUT COLD AIR ADVECTION WILL RESULT IN HIGH TEMPERATURES
BEING SEVERAL DEGREES BELOW NORMAL. UPPER TROUGH TO PERSIST OVER
EASTERN CANADA THURSDAY AND FRIDAY FOR A CONTINUATION OF THE DRY
WEATHER WITH SLOWLY MODERATING TEMPERATURES...BUT VALUES WILL
STILL BE SLIGHTLY BELOW NORMAL. EVENTUALLY THE FLOW ALOFT BACKS TO
THE WEST AND SOUTHWEST OVER THE WEEKEND...SO THE WARMING TREND
WILL CONTINUE TO APPROACH SEASONAL LEVELS. DRY WEATHER WILL
CONTINUE TO BE THE RULE. IF THERE IS ANY CHANCE FOR SHOWERS...A
SMALL CHANCE AT BEST...IT WOULD BE ON FRIDAY AS A WEAK FRONT DROPS
DOWN INTO THE AREA FROM THE NORTH.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
THROUGH 18Z MONDAY...STILL LOOKING AT VFR CONDITIONS THROUGH MOST
OF THE PERIOD. THE ONLY EXCEPTION TO THIS WILL BE A PERIOD OF IFR
TO VLIFR CONDITIONS AT KSLK AND KMPV BETWEEN 07Z AND 12Z.
OTHERWISE...WINDS WILL BE VARIABLE AT SPEEDS UNDER 10 KNOTS
THROUGH MUCH OF THE PERIOD.
OUTLOOK 18Z MONDAY THROUGH THURSDAY...
18Z MONDAY THROUGH 00Z TUESDAY...MAINLY VFR UNDER SURFACE HIGH
PRESSURE.
00Z TUESDAY THROUGH 00Z WEDNESDAY...OCNL MVFR IN RAIN SHOWERS AS COLD
FRONT MOVES ACROSS THE REGION.
00Z WEDNESDAY THROUGH 00Z SATURDAY...MAINLY VFR AS HIGH PRESSURE RETURNS
TO THE REGION.
&&
.EQUIPMENT...
AS OF 337 PM EDT SUNDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LOCONTO
NEAR TERM...LOCONTO
SHORT TERM...LOCONTO
LONG TERM...EVENSON
AVIATION...EVENSON/WGH
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1253 PM EDT SUN AUG 11 2013
.SYNOPSIS...
A LARGE HIGH PRESSURE SYSTEM WILL REMAIN IN CONTROL OF THE WEATHER
PATTERN TODAY...ALLOWING FOR ONE MORE COMFORTABLE AND RAIN FREE
DAY ACROSS OUR REGION. HIGH TEMPERATURES WILL WARM INTO THE LOWER
TO MIDDLE 70S ACROSS MUCH OF THE AREA...WITH A FEW LOW 80S POSSIBLE
ACROSS THE LOWER WYOMING VALLEY. BY MONDAY...RAIN CHANCES WILL
INCREASE DURING THE LATE AFTERNOON AS A WEAK AREA OF LOW PRESSURE
BEGINS MOVING NORTH ALONG THE MID-ATLANTIC COAST. BY MONDAY NIGHT
AND TUESDAY...EXPECT RAIN CHANCES TO INCREASE AS A STRONG COLD
FRONT MOVES THROUGH THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
945 AM UPDATE... MORE IN THE WAY OF CLDNS...ALG WITH ISOLD
-SHRA/SPRINKLES WERE ADDED TO THE FCST TDY FOR OUR FAR SRN ZNS.
OTHWS...NO SIG CHGS ATTM.
SAT/RADAR IMAGERY SHOW A CLOUD BAND (GENERALLY 4-7 K FT AGL) MOVG
ACRS PA LATE THIS MRNG...ALG WITH POTENTIALLY A FEW SPRINKLES. A
CLOSER INSPECTION OF THE THERMAL/MOISTURE FIELDS SHOW SOME 850 MB
FGEN THIS RGN...OWING TO A NARROW RGN OF CONVERGENT FLOW...AND
ASSOCD MOIST CONDS/HIGHER DEW PTS. THE LATEST HRRR RUNS SEEM TO
PICK UP ON THIS SCENARIO...AND SHOW SOME WEAK RETURNS MOVG ACRS
PTNS OF NE PA THROUGH MID TO LATE AFTN. ALTHOUGH WE CERTAINLY
DON`T EXPECT MUCH PCPN OUT OF THIS...WE FELT IT PRUDENT TO THROW
IN ISOLD SHWRS/SPRINKLES...AND OBVIOUSLY INSERT ADDTNL CLOUD
COVER OVER THE NEAR-TERM.
DUE TO THE SHALLOW NATURE OF THE AFOREMENTIONED AREA OF
MOISTURE...WE THINK IT COULD MIX OUT TO SOME DEGREE DURG THE
AFTN. THUS...WE`RE ONLY CARRYING ISOLD/SCHC POPS TIL 18-21Z.
ALSO...WE THINK SOME BREAKS OF SUNSHINE ARE LIKELY TO DVLP THIS
AFTN OVER SRN PTNS OF THE FA...AND GIVEN THIS...WE DIDN`T DEVIATE
MUCH FROM OUR EARLIER HIGH TEMP FCST (GENERALLY 75-80 DEGS).
FARTHER N ACRS CNY...LIFE IS GOOD...WITH A DRY AMS/SINKING MOTION
REGIME IN PLACE. ONLY SOME SPOTTY FAIR WX CU IS ANTICIPATED...WITH
A GENERALLY SUNNY AFTN ON TAP.
PREV DISC... 08Z MSAS SURFACE ANALYSIS SHOWING A LARGE AREA OF
HIGH PRESSURE EXTENDING ACROSS MUCH OF THE GREAT LAKES REGION THIS
MORNING...WITH TEMPS LARGELY HOVERING IN THE LWR 50S. 11-3.9U
SATELLITE IMAGERY SHOWING A FEW PATCHES OF MID-LEVEL CLOUDS
STREAMING ACROSS THE REGION AS MOISTURE REMAINS TRAPPED BELOW A
FAIRLY STRONG SUBSIDENCE INVERSION WHICH IS READILY APPARENT ON
THE 00Z BUF RAOB. HEADING INTO TODAY...THESE CLOUDS WILL LIKELY
DISSIPATE AS DAYTIME HEATING COMMENCES BEFORE SOME SCATTERED FLAT
CU DEVELOP BY LATE MORNING AND EARLY AFTERNOON.
WITH NO SENSIBLE WX EXPECTED TODAY...MAIN FCST ISSUE REMAINS
CENTERED ON DAYTIME TEMPS. 850 TEMPS ARE FORECAST TO RISE A DEGREE
OR TWO OVER YESTERDAY/S VALUES...HOWEVER LOW-LEVEL FLOW WILL
REMAIN FROM THE NORTHWEST THROUGH A GOOD CHUNK OF THE DAY.
CONSIDERING MOST LOCATIONS UP ACROSS THE LAKE PLAIN REMAINED A FEW
DEGREES BELOW MODEL GUIDANCE ON SATURDAY...HAVE ELECTED TO
MAINTAIN A SIMILAR TREND TODAY WITH LOW TO MID 70S EXPECTED UP
NORTH...WITH MID TO UPPER 70S ANTICIPATED FROM THE TWIN TIERS
SOUTH.
A SIMILAR NIGHT EXPECTED TONIGHT WITH HIGH PRESSURE REMAINING IN
CONTROL OF THE WX PATTERN. THE ONLY POTENTIAL FLY IN THE OINTMENT
WILL BE A WEAK SHORTWAVE MOVING EAST THROUGH CENTRAL PA OVERNIGHT
WITH THE GFS OFFERING SOME LIGHT SHWR ACTIVITY ACROSS SOUTHEASTERN
PA AS WEAK WARM AIR ADVECTION INTERACTS WITH A MARINE FRONT.
THERE IS SOME POTENTIAL THAT SOME SHWRS MAY TRY BUILDING UP
TOWARDS OUR NE PA ZONES HOWEVER DECIDED TO LEAVE THE FCST DRY
CONSIDERING HOW DRY THE ATMOSPHERE CURRENTLY IS. WILL ALLOW THE
DAY SHIFT TO TAKE ANOTHER LOOK BEFORE DECIDED WHETHER A MENTION
WILL BE NEEDED. OVERNIGHT LOWS WILL AGAIN FALL INTO THE LOWER TO
MIDDLE 50S WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED
ALOFT. THIS SHOULD ALLOW FOR GREAT VIEWING CONDITIONS OF THE
PERSEID`S METEOR SHOWER.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
CLOUDS TO BE ON THE INCREASE THROUGH THE DAY ON MONDAY AS STRONG
SHORTWAVE TROUGH ROTATES SOUTHEAST FROM WESTERN ONTARIO INTO THE
NORTH-CENTRAL LAKES. AS THIS OCCURS...STRENGTHENING SFC LOW
PRESSURE WILL BEGIN TRACKING FROM NORTHERN MICHIGAN INTO SOUTH-
CENTRAL ONTARIO...WITH A COLD FRONT EXTENDING WELL SOUTH THROUGH
THE OHIO VLY. A RETURN OF SOUTHERLY WINDS IN ADVANCE OF BOTH
FEATURES WILL LEAD TO INCREASING MOISTURE ADVECTION THROUGH THE
DAY WITH FCST MODELS HIGHLIGHTING POSSIBLE SHOWERS/ISO STORMS
ACROSS THE WESTERN ZONES BY LATE AFTERNOON...WITH ANOTHER AREA OF
SHWRS POSSIBLE ACROSS FROM NORTHEAST PA NORTH INTO THE CATSKILLS
AS AFOREMENTIONED MARINE FRONT LIFTS NORTH TOWARDS THE REGION.
BOTH THE GFS AND NAM SHOW A SHORTWAVE MOVING ACROSS THE REGION
DURING THE AFTERNOON OFFERING A LITTLE SYNOPTIC SCALE FORCING FOR
POSSIBLE DEVELOPMENT. AS SUCH...HAVE INCREASED POPS INTO THE CHC
CATEGORY BEGINNING IN THE AFTERNOON FROM THE TWIN TIERS AND
WESTERN FINGER LAKES SOUTH...BEFORE RISING POPS FURTHER TO THE
NORTH BY THE END OF THE PERIOD. INSTABILITY LOOKS MEAGER AT BEST
ONCE AGAIN HOWEVER WITH A FEW HUNDRED JOULES POTENTIALLY
AVAILABLE...HAVE DECIDED TO OFFER AN ISOLATED THUNDER MENTION.
MAIN COLD FRONT TO SLIDE THROUGH THE AREA ON TUESDAY WITH ALL
INDICATIONS SUGGESTING THE COLD FRONT WILL BEGIN MOVING THROUGH
OUR AREA BETWEEN THE 12-15Z TIME FRAME. BEYOND THIS...FEATURE WILL
QUICKLY RACE TO THE SOUTHEAST AS MAIN EASTERN CANADIAN CLOSED LOW
RETREATS TOWARDS EASTERN QUEBEC AND TRAILING SHORTWAVE ENERGY
QUICKLY SETTLES SOUTH ACROSS OUR AREA. THUS EXPECT A GRADUAL
DECREASE IN SHWRS/ISO STORMS THROUGH THE EVENING WITH DRY BUT COOL
CONDITIONS THEN ANTICIPATED TUE NIGHT. FOR NOW...MODEL TRENDS
SUGGEST BEST INSTABILITY WILL BE EAST OF OUR REGION LENDING HOPE
THAT ANY ORGANIZED SEVERE WX WILL NOT IMPACT OUT AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
LTL CHG TO THE MED RNG FCST WTIH WPC GDNC LOOKING GOOD. SFC HIGH
PRESSURE IN THE VICINITY...WITH A BEAUTIFUL STRETCH OF WEATHER FOR LATE
SUMMER. POTNL FOR SOME -SHRA LATE IN THE PD IF WE CAN GET SOME
ATLC MSTR INTO THE AREA. TEMPS MODIFYING TO NEAR SEASONAL NORMS
FOR DAYTIME HIGHS...BUT THE NIGHTS WILL CONTINUE TO BE ON THE COOL
SIDE UNTIL LATE IN THE WEEK.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR TO PREVAIL THRU 18Z MON. DIURNAL CU WILL DSPT LATER THIS
AFTN...WITH GNRLY SKC EARLY THIS EVNG GIVING WAY TO SOME SCT-BKN
MID AND HI CLDS TNGT. THESE CLDS MAKE THE ELM FOG FCST
INTERESTING...AS OTHER PARAMS LOOK QUITE FVRBL FOR REDVLPMNT OF
VLY FOG TNGT. CHECKLIST ALSO INDICATES A GOOD CHC FOR DENSE FOG.
FOR NOW WE`LL GO WITH A 2SM BR TEMPO 1/2 FG FROM 09-12Z...WHICH
WILL HAVE TO BE REVISITED IN LATER UPDATES. FOR TMRW...PSSG OF A
MID LVL S/WV WITH BKN100 XPCTD TO PREVAIL. WINDS THIS AFTN ARND 5
KTS MAINLY FROM THE W OR NW...L&V TNGT WITH TYPICAL DRAINAGE
FLOWS...THEN WRLY ON MON 5-10 KTS.
OUTLOOK...
MON NGT/TUE...MVFR IN SHRA/TSRA.
WED/THU/FRI...VFR...BRIEF IFR PSBL AT ELM IN EARLY MRNG VLY FOG.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/MLJ
SHORT TERM...CMG
AREA FORECAST DISCUSSION
NWS RALEIGH NC
200 PM EDT SUN AUG 11 2013
.SYNOPSIS...
A SURFACE TROUGH WILL LINGER OVER THE CAROLINAS AND MIDDLE ATLANTIC
REGION THROUGH TUESDAY. A COLD FRONT WILL THEN CROSS OUR AREA
TUESDAY NIGHT...AND REMAIN STALLED ALONG THE COAST THROUGH THE REST
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM SUNDAY...
THE PATTERN WILL REMAIN RATHER PERSISTENT THROUGH THE NEAR TERM...
WITH ADDITIONAL SHOWERS AND THUNDERSTORMS EXPECTED THIS AFTERNOON
AND EVENING. REGIONAL RADAR SHOWS SHOWERS AND THUNDERSTORMS JUST TO
OUR WEST ACROSS THE FOOTHILLS...AND THESE ARE EXPECTED TO CONTINUE
MOVING EAST WITH NEW DEVELOPMENT EASTWARD ON OUTFLOW BOUNDARIES.
ALSO NOTED A WEAK/SHEARED SHORT WAVE EMBEDDED IN THE MID LEVEL FLOW
CURRENTLY MOVING ACROSS THE MOUNTAINS. THIS FEATURE MAY PROVIDE SOME
ADDITIONAL SUPPORT FOR THE ONGOING ACTIVITY. LATEST OBSERVED
CONVECTIVE PARAMETERS ARE SIMILAR TO YESTERDAY...SO IN TERMS OF
IMPACTS...TODAYS THUNDERSTORMS WILL ONCE AGAIN BE CAPABLE OF MAINLY
BRIEF INTENSE DOWNPOURS AND FREQUENT TO EXCESSIVE-AT-TIMES CG
LIGHTNING. STILL CAN`T RULE OUT A COUPLE ISOLATED DAMAGING WIND
GUSTS...ALTHOUGH ITS WORTH NOTING THAT THE LATEST DCAPE VALUES
ACROSS ALL OF CENTRAL NC ARE BELOW 600 J/KG...WITH THE RAP SHOWING
LITTLE INCREASE THROUGH THE AFTERNOON.
ACTIVITY SHOULD WIND DOWN BY MIDNIGHT...WITH PC SKIES THE REST OF
THE NIGHT AND SOME PATCHY FOG...PARTICULARLY NEAR AREAS THAT RECEIVE
HEAVIER RAIN THIS AFTERNOON. LOWS TONIGHT WILL BE SIMILAR TO PREV
NIGHTS...LOWER 70S.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 200 PM SUNDAY...
IN THE BIG PICTURE...THE L/W TROUGH OVER NE NORTH AMERICA WILL BEGIN
TO DEEPEN SOUTHWARD AS A S/W TROUGH EMBEDDED WITHIN THE L/W TROUGH
MOVES SOUTH ACROSS THE GREAT LAKES. FOR OUR AREA...FORECAST
SOUNDINGS SHOW SUBTLE DRYING IN THE WAKE OF THE OF THE WEAK S/W
TROUGH THAT WILL CROSS OUR AREA LATER TODAY. HOWEVER...WITH PWAT
STILL PROGGED TO REMAIN AT OR SLIGHTLY ABOVE 1.75 INCHES...LITTLE
OVERALL CHANGE IN THE CONVECTIVE PARAMETERS FROM TODAY...AND THE
PIEDMONT TROUGH PROVIDING LOW LEVEL SUPPORT...LOOK FOR ADDITIONAL
SCATTERED AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS...
WITH THE MAIN IMPACTS ONCE AGAIN BEING DOWNPOURS...CG LIGHTNING...
AND PERHAPS AN ISOLD DAMAGING WIND GUST OR TWO. ITS WORTH NOTING
THAT MOST CAMS SHOW LESS COVERAGE OF THIS ACTIVITY COMPARED TO
TODAY...PERHAPS A RESULT OF THE SUBTLE DRYING AND LIMITED LARGE
SCALE SUPPORT. GIVEN SLIGHTLY LOWER HEIGHTS AND SUBSEQUENT THICKNESS
VALUES...HIGHS ON MONDAY SHOULD BE A DEGREE TO TWO LOWER THAN
TODAY...STILL AROUND 90 FOR MOST PLACES ALONG WITH PLENTY OF
HUMIDITY. THE HIGHEST HEAT INDEX VALUES IN OUR CWA WILL BE IN THE
UPPER 90S ACROSS OUR SE ZONES WHERE SFC DWPTS WILL BE THE HIGHEST.
MONDAY NIGHT...A WEAK S/W TROUGH IN THE SW FLOW IS PROGGED TO MOVE
ACROSS THE MID ATLANTIC REGION. THE SYNOPTIC SCALE MODELS ARE MORE
AGGRESSIVE WITH PRECIP/QPF AS A RESULT OF THIS SYSTEM...WHILE MANY
OF THE CAMS ARE LESS ENTHUSIASTIC FOR MUCH PRECIP ACROSS OUR AREA...
LIKELY THE RESULT OF LOSS OF DAYTIME HEATING. SINCE THERE WILL BE
SOME SYNOPTIC FORCING IN THE AREA...PREFER TO KEEP AT LEAST A SLIGHT
CHANCE POP ACROSS OUR ZONES DURING THIS TIME. LOWS ONCE AGAIN IN THE
LOWER 70S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 200 PM SUNDAY...
THE LONG TERM FORECAST IS STILL ON TRACK FOR A VERY WET PERIOD FROM
TUESDAY THROUGH SUNDAY WITH A FRONTAL ZONE STALLING OUT OVER THE
AREA AS MULTIPLE SHORTWAVES PROGRESS ALONG IT. 6Z GEFS ANOMALIES
SHOW PRECIPITABLE WATER VALUES 2-3 STANDARD DEVIATIONS ABOVE NORMAL
IN THE SOUTHERN PORTION OF THE AREA WITH RAW VALUES OF 2-2.5 INCHES
THROUGH MUCH OF THE LONG TERM. COMPETING FOR NOTORIETY WILL BE HIGH
TEMPERATURES...THURSDAY IN PARTICULAR...WHEN HIGHS IN THE TRIAD
COULD BE ONLY IN THE LOW TO MID 70S. BOTH THE ECMWF AND GFS ARE
SHOWING THICKNESS VALUES IN THE HIGH 1360S WHICH CORRESPONDS TO
NORMAL VALUES FOR EARLY MAY...NOT EARLY AUGUST. THE LARGEST SEVERE
THREAT DURING THIS PERIOD WILL BE FLOODING AS WPC IS STILL SHOWING 7
DAY TOTALS 2.5-3 INCHES IN THE TRIAD...3-4 INCHES IN THE
TRIANGLE...AND 5 PLUS ON THE COAST.
FOR TUESDAY THE FRONT IS PROGGED TO SET UP OVER UPSTATE SOUTH
CAROLINA AND THE COASTAL PLAIN OF NORTH CAROLINA. FORECAST SOUNDINGS
IN BUFKIT SHOW A SETUP SIMILAR TO THE LAST COUPLE OF DAYS WITH GOOD
INSTABILITY ALONG WITH MODERATE SHEAR VALUES...LEADING TO MOST
LIKELY MULTICELLULAR OR BROKEN LINE TYPE CONVECTION. BY
WEDNESDAY...WITH THE FRONTAL STILL PARKED TO THE SOUTH...THE SURFACE
HIGH BEGINS TO MOVE EASTWARD...BEGINNING TO DEVELOP THE WEDGE AS.
INSTABILITY CRASHES BUT SHEAR INCREASES TO 40-50 KNOTS. SOUNDINGS
BECOME VERY SATURATED IN THE LOW LEVELS AS WARM RAIN PROCESSES
BECOME DOMINANT. ANAFRONTAL RAIN WILL SPREAD NORTHWARD THROUGH NC
AND INTO SOUTHERN VA BY WEDNESDAY EVENING. SURFACE TEMPERATURES WILL
COOL IN RESPONSE TO CLOUD COVER AND THE NORTHEASTERLY SURFACE WINDS
BROUGHT ON BY THE FORMATION OF THE WEDGE FRONT. THIS GENERAL PATTERN
CONTINUES THROUGH THE DAY ON THURSDAY. AN ADDED PUNCH TO THE
RAINFALL TOTALS ON THURSDAY COULD BE PROVIDED BY A MESO-LOW MOVING
UP FROM GEORGIA THROUGH SOUTH CAROLINA AND INTO OUR CWA FROM THE
SOUTHWEST.
ON FRIDAY...THE SOUNDINGS DRY OUT A LITTLE BIT...AS THE MESO-LOW
EXITS TO THE NORTHEAST...TAKING A LOT OF MOISTURE WITH IT. A SMALL
SURFACE HIGH TRIES TO FORM OVER THE CAROLINAS AND MID-LEVEL DRY AIR
WILL EVENTUALLY WORK DOWN TO THE SURFACE ALTHOUGH SUFFICIENT MID AND
UPPER LEVEL SATURATION WILL KEEP IT CLOUDY THROUGH SATURDAY NIGHT.
PRECIPITATION CHANCES WILL BE BEST ALONG THE COAST AS AN INVERTED
TROUGH SETS UP OVER THE COAST. MUCH FURTHER SOUTH IN THE GULF OF
MEXICO...THE GFS SPINS UP A TROPICAL SYSTEM WHICH HEADS FOR MOBILE
BAY...BUT THIS FEATURE HAS NOT YET APPEARED IN THE ECMWF.
LOW LEVEL MOISTENING BEGINS AGAIN ON SUNDAY WITH THE RETURN OF
RAILROAD TRACK SOUNDINGS AND AT LEAST SOME LOW LEVEL INSTABILITY
AHEAD OF WHAT MAY OR MAY NOT BE A TROPICAL SYSTEM MOVING INTO
ALABAMA. REGARDLESS OF WHAT IT IS...THE LOW PRESSURE SYSTEM COUPLED
WITH THE HIGH OFF THE COAST WILL FUNNEL EVEN MORE MOISTURE INTO THE
CAROLINAS FOR SUNDAY AND BEYOND INTO THE WORK WEEK.
TEMPERATURES WILL SHOW A COOLING TREND EARLY IN THE LONG TERM WITH
UPPER 80S ON TUESDAY CRASHING TO THE LOW 80S BY WEDNESDAY AND DOWN
INTO THE MID TO UPPER 70S...AT LEAST IN THE NW...THURSDAY AND FRIDAY
BEFORE REBOUNDING BACK INTO THE LOW 80S IN MOST PLACES BY SUNDAY.
EXPECT LOWS IN THE UPPER 60S TO LOW 70S EARLY ON FOLLOWED BY LOW TO
MID 60S LATE IN THE PERIOD.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 1255 PM SUNDAY...
SIMILAR TO YESTERDAY...SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP ACROSS CENTRAL NC AROUND 18Z. STORMS MAY BRIEFLY
REDUCE CIGS AND VSBY TO IFR CONDITIONS...ALONG WITH ISOLD 30-40 KT
WIND GUSTS. OUTSIDE OF TSTM ACTIVITY...EXPECTED VFR CONDITIONS
THROUGH THIS EVENING. LATER TONIGHT...SOME PATCHY FOG MAY REDUCE
VSBY TO 1-3 MILES...HOWEVER THIS IS MOST LIKELY TO OCCUR NEAR
LOCATIONS THAT RECEIVE HEAVIER RAINFALL THIS AFTERNOON. AFT 12/13Z
AND THROUGH THE REST OF THE TAF PERIOD...EXPECT VFR CONDITIONS AFTER
FOG BURNS OFF.
LOOKING AHEAD:
SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND STORMS...AND
PATCHY MORNING FOG AND/OR LOW STRATUS WHERE STORMS OCCUR THE DAY
BEFORE...ARE EXPECTED THROUGH TUE NIGHT. THEN A MORE ACTIVE AND WET
PERIOD OF WEATHER MAY OCCUR DURING THE MID-LATE PORTION OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NP
NEAR TERM...NP
SHORT TERM..NP
LONG TERM...RTE
AVIATION...NP
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
319 PM EDT SUN AUG 11 2013
.SYNOPSIS...
STATIONARY FRONT LINGERS ACROSS THE OHIO VALLEY AND WEST VIRGINIA TONIGHT.
UPPER LEVEL DISTURBANCES MONDAY NIGHT...OLD BOUNDARY LIFT NORTH AS
A WARM FRONT. COLD FRONT TUESDAY. COOLER AND DRIER AIRMASS MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
OVERALL PATTERN REMAINS THE SAME TODAY AND ESSENTIALLY FOR ONE MORE
DAY WITH FORECAST AREA WITHIN ZONAL FLOW REGIME IN THE BASE OF
LONGWAVE UPPER TROUGH CENTERED OVER ONTARIO/QUEBEC CANADA. S/W
TROUGHS WITH ASSOC VORT MAXES CONTINUE TO PERIODICALLY MOVE ACROSS
THE AREA THROUGH THE MEAN FLOW WITH WEAK DIFFUSE SFC FRONT
CONTINUING TO MEANDER ACROSS THE NORTHERN PART OF THE AREA. OVERALL
THREAT FOR FLASH FLOODING HAS SUBSIDED BUT THE PRIMARY FORECAST
CONCERN CONTINUES TO BE THE TIMING OF VORT MAXES AND SUBSEQUENT OFF
AND ON AGAIN PRECIP CHANCES.
TOUGH TO PICK OUT THE QUASI-STATIONARY DIFFUSE SFC FRONT AT 15Z SFC
ANALYSIS WITH TEMPS ALONE. A GOOD MOISTURE GRADIENT STILL IN PLACE
ACROSS THE NORTHERN PART OF THE FORECAST AREA BUT DEWPTS HAVE RISEN
2-5 DEGREES IN THE PAST 2-3 HOURS ACROSS NW ZONES...INDICATING
PERHAPS SOME NORTHERN RETREAT TO THE FRONT. PRESSURE FIELD ALSO SEEM
TO INDICATE FRONT LOCATED ROUGHLY JUST NORTH OF PBZ SOUTHWESTWARD TO
NEAR PERRY COUNTY OH TO NEAR CINCINNATI...WITH A VERY WEAK SFC LOW
OVER SC OHIO. THIS MORNING/S ONGOING PRECIP ACROSS THE SOUTHERN
ZONES ASSOC WITH YET ANOTHER VORT MAX EXPECTED TO CONTINUE EASTWARD
AS THE VORT MAX PUSHES EAST AS WELL. LATEST RUC13 AND NAM12
DEPICTING THE NEXT RIPPLE/VORT MAX APPROACHING NW ZONES BTWN 21Z AND
00Z MON. A FEW SHOWERS ALREADY POPPING UP NEAR FRONT ACROSS NC KY
AND SW OHIO NEAR FRONTAL ZONE. WILL MOST LIKELY INCREASE PRECIP
CHANCES ACROSS THE WESTERN ZONES BY MID/LATE AFTERNOON TO CHANCE TO
ACCOUNT FOR POTENTIAL ACTIVITY PUSHING INTO THE NW ZONES. NOT
EXPECTING MUCH IN THE WAY OF SEVERE POTENTIAL WITH THIS ACTIVITY BUT
A FEW OF THESE COULD BE ON THE STRONGER SIDE. MEANWHILE ALSO EXPECT
SHOWERS AND THUNDERSTORMS TO CONTINUE TO INCREASE IN COVERAGE OVER
SOUTHERN AND SOUTHEAST ZONES WHERE BETTER DEEP LAYER MOISTURE
CONTINUES TO RESIDE.
OVERNIGHT ANY ONGOING CONVECTION SHOULD DISSIPATE RAPIDLY WITH THE
LOSS OF DAYTIME HEATING...WITH THE CONVECTION NO LONGER TIED TO THE
SFC FRONT WHICH IS PROGGED TO REMAIN WEST WITH THE APPROACH OF A SFC
LOW OVER SOUTHERN GREAT LAKES. EXPECT LOWLANDS TO BE DRY BY 06Z
MON...AND REMOVED POPS FOR ALL LOCATIONS BY 09Z MON. CLOUDS WHICH
WILL INITIALLY ATTEMPT TO SCATTER INTO A MOSTLY CLEAR TO PARTLY
CLOUDY SKY EARLY ON MAY REFORM INTO A LOW STRATUS DECK...PARTICULARLY
OVER THE WV LOWLANDS WHERE DEWPOINTS REMAIN RELATIVELY HIGH...WITH
NAM12 BUFKIT SOUNDINGS INDICATING COMPLETE SATURATION UP TO AROUND
700FT AGL WITH SLIGHTLY STRONGER WINDS AT 925MB CREATING SOME
OVERTURNING. RECENT RUC13 SOUNDING LESS ROBUST ON THIS SATURATED
LAYER...SO STRATUS DECK STILL SOMEWHAT IN QUESTION. EITHER
WAY...STILL EXPECT THE USUAL VALLEY FOG AND HAZE AS WELL.
MONDAY...THE AREA STARTS OFF DRY WITH INITIAL ZONAL FLOW. HOWEVER AS
HAS BEEN THE CASE AS OF LATE...FLOW QUICKLY RETURNS TO THE W/SW BY
18Z MON AS THE NEXT S/W TROUGH AND VORT MAX QUICKLY DIVES AROUND THE
BASE OF THE LONGWAVE TROUGH INTO THE LOWER AND MID OHIO RIVER VALLEY
DURING THE AFTERNOON HOURS. EARLY MORNING CLOUDS IN PLACE SHOULD
SLOWLY ERODE BY MID TO LATE MORNING AND LEAVE BEHIND A GENERALLY
PARTLY CLOUDY SKY BY EARLY AFTERNOON. WILL BRING IN SLIGHT CHANCE TO
LOW CHANCE POPS BY THE AFTERNOON HOURS FROM WEST TO EAST BUT EXPECT
THE BULK OF THE PRECIP TO HOLD OFF UNTIL THE EVENING HOURS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
GFS MODEL SHOWS A VORT MAX FEATURE...AHEAD OF A PARENT LONGWAVE
TROUGH...APPROACHING FROM THE NORTHWEST BY 00Z TUESDAY. NAM
SOLUTION BRING DEEP MOISTURE ALONG A SMALL AREA OF H6 2D
FRONTOGENESIS AROUND THE TRI STATE AREA BY 00Z TUESDAY. SOUTHWEST
FLOW INJECTS MOISTURE INTO WV MONDAY NIGHT...ALLOWING SHOWERS AND
STORMS TO DEVELOP DURING THE OVERNIGHT HOURS. A BOUNDARY LAYER
COVERGENCE ZONE IS ALSO EVIDENT LIFTING NORTH FROM 00-03Z TUESDAY
WITH PWATS AROUND 1.8 INCHES. BOTH MODELS ARE IN AGREEMENT IN
THEIR QPF FIELDS WITH THE AFOREMENTIONED SHORTWAVE.
INCREASE POPS WITH THIS WARM-FRONT- LIKE FEATURE LIFTING NORTH
LATE MONDAY NIGHT.
A PRE FRONTAL TROUGH APPROACHES FROM THE NORTHWEST...EVIDENT IN BL
CONVERGENCE FIELDS...SFC CAPE AROUND 1000 J/KG WITH A GRADIENT JUST
NORTHWEST...AND PWATS AROUND 1.75. THEREFORE...ADJUSTED POPS TO
LIKELY/CATEGORICAL WITH THE PRE-FRONTAL WAVE TUESDAY. CODED A LULL
IN POPS AFTER SECOND ROUND OF SHOWERS OR STORMS ASSOCIATED WITH
PRE FRONTAL TROUGH...BEFORE INCREASING POPS BACK TO HIGH
LIKELIES...AND EVEN CATEGORICAL OVER NORTHEAST MOUNTAINS THROUGH
EARLY TUESDAY NIGHT. FLOW TURNS FROM THE NORTH LATE TUESDAY NIGHT
AND WEDNESDAY.
RELATIVELY COOLER AND DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT
TUESDAY NIGHT WITH LINGERING CLOUDS...DECREASING CLOUDS AND POPS
FROM WEST TO EAST TUESDAY NIGHT. EXPECT PLEASANT TEMPERATURES
TUESDAY NIGHT AND WEDNESDAY WITH TEMPERATURES BELOW NORMAL.
THE FRONT CLEAR THE MOUNTAINS BY LATE TUESDAY NIGHT.
BLENDED THE BIAS CORRECTED NAM WITH SREF SOLUTIONS FOR
TEMPERATURES THROUGH THE PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE BUILDS FROM THE WEST...AS A COLD FRONT EXITS EAST OF
THE APPALACHIANS WEDNESDAY MORNING. NORTHERLY FLOW CONTINUES
THURSDAY KEEPING FRESH AND COOLER AIRMASS IN PLACE. THIS BROAD
HIGH PRESSURE WILL BRING SUBSIDENCE...CLEAR SKIES...AND COOLER
TEMPERATURES AREA EXPECTED THROUGH THE END OF THE WEEK.
FLOW BECOMES NORTHERLY EARLY WEDNESDAY THROUGH FRIDAY.
THEREFORE...HIGHS WILL STRUGGLE TO REACH THE MID TO LOWER
80S...WHILE LOWS WILL DEPEND ON EITHER SKIES CLEAR OR NOT. CLEAR
SKIES COULD ALLOW RADIATIONAL COOLING DURING THE NIGHTS...CAPABLE
TO DROP LOW TEMPERATURES INTO THE MID 50S BY THURSDAY. THE GFS
MODEL SUGGEST A SHARP H5 TROUGH APPROACHES FROM THE WEST FRIDAY
NIGHT INTO SATURDAY.
THEREFORE...ADJUSTED POPS...SKY...AND TEMPERATURES. USED THE HPC
GUIDANCE FOR TEMPERATURES AND POPS...WITH SOME TIMING TWEAKING IN
BETWEEN.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
18Z SUNDAY THRU 18Z MONDAY...
SHOWERS WITH A FEW THUNDERSTORMS CONTINUE THIS AFTERNOON MAINLY
ACROSS THE SOUTHERN ZONES...WITH MORE SHOWERS AND THUNDERSTORMS
OVER CENTRAL AND SW OHIO MOVING EASTWARD TOWARDS THE TRI-STATE
AREA AND SE OHIO. EXPECT MAINLY VFR CONDITIONS TO PREVAIL THIS
AFTERNOON...WITH THE EXCEPTION OF BKW WHERE MVFR CIGS SHOULD
PREVAIL WITH PERHAPS SOME INTERMITTENT VFR. SHOULD A SHOWER OR
STORM DIRECTLY IMPACT A TERMINAL...INTERMITTENT MVFR CIGS WITH
MVFR/IFR VIS WILL LIKELY RESULT WITH BRIEF HEAVY RAINFALL.
OVERNIGHT SHOWERS AND THUNDERSTORMS WILL DIMINISH IN COVERAGE AND
INTENSITY WITH MOST LOCATIONS DRY BY 06Z. FOG AND/OR LOW STRATUS
WILL LIKELY FORM AFTER 06Z AND TOWARDS THE DAWN HOURS WITH SKIES
ATTEMPTING TO SCATTER TO MOSTLY CLEAR BY 09Z ACROSS MOST LOWLAND
LOCATIONS WITH ABUNDANT LLVL MOISTURE AND RECENT RAINS. CONDITIONS
ARE EXPECTED TO IMPROVE DURING THE MORNING HOURS AS USUAL...BUT
IMPROVEMENT MAY BE A BIT SLOWER THAN NORMAL AS A POTENTIAL STOUT
LOW STRATUS DECK MAY BE A BIT STUBBORN TO SCATTER.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: REDEVELOPMENT OF CONVECTION THIS AFTERNOON
AND EVENING COULD VARY. TIMING OF ONSET FOG TONIGHT AND
IMPROVEMENT OF FLIGHT CONDITIONS EARLY MON MORNING MAY 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.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M M M M M M M H H M L L
HTS CONSISTENCY M M M H H H H H H M L L
BKW CONSISTENCY H H H H M M M M M H H H
EKN CONSISTENCY H H H H H H M H H M L L
PKB CONSISTENCY H H H H H H H H H M L L
CKB CONSISTENCY H H H H H H H H H M M L
AFTER 18Z MONDAY...
IFR POSSIBLE IN FOG/LOW STRATUS MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/50
NEAR TERM...50
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...50
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
248 PM EDT SUN AUG 11 2013
.SYNOPSIS...
STATIONARY FRONT LINGERS ACROSS THE OHIO VALLEY THROUGH MONDAY.
UPPER LEVEL DISTURBANCE MONDAY NIGHT. COLD FRONT TUESDAY. COOLER
AND DRIER AIRMASS MIDWEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
OVERALL PATTERN REMAINS THE SAME TODAY AND ESSENTIALLY MONDAY AS
WELL FOR ONE MORE DAY WITH FORECAST AREA WITHIN ZONAL FLOW REGIME IN
THE BASE OF LONGWAVE UPPER TROUGH CENTERED OVER ONTARIO/QUEBEC
CANADA. S/W TROUGHS WITH ASSOC VORT MAXES CONTINUE TO PERIODICALLY
MOVE ACROSS THE AREA THROUGH THE MEAN FLOW WITH WEAK DIFFUSE SFC
FRONT CONTINUING TO MEANDER ACROSS THE NORTHERN PART OF THE AREA.
OVERALL THREAT FOR FLASH FLOODING HAS SUBSIDED BUT THE PRIMARY
FORECAST CONCERN CONTINUES TO BE THE TIMING OF VORT MAXES AND
SUBSEQUENT OFF AND ON AGAIN PRECIP CHANCES.
TOUGH TO PICK OUT THE QUASI-STATIONARY DIFFUSE SFC FRONT AT 15Z SFC
ANALYSIS WITH TEMPS ALONE. A GOOD MOISTURE GRADIENT STILL IN PLACE
ACROSS THE NORTHERN PART OF THE FORECAST AREA BUT DEWPTS HAVE RISEN
2-5 DEGREES IN THE PAST 2-3 HOURS ACROSS NW ZONES...INDICATING
PERHAPS SOME NORTHERN RETREAT TO THE FRONT. PRESSURE FIELD ALSO SEEM
TO INDICATE FRONT LOCATED ROUGHLY JUST NORTH OF PBZ SOUTHWESTWARD TO
NEAR PERRY COUNTY OH TO NEAR CINCINNATI...WITH A VERY WEAK SFC LOW
OVER SC OHIO. THIS MORNING/S ONGOING PRECIP ACROSS THE SOUTHERN
ZONES ASSOC WITH YET ANOTHER VORT MAX EXPECTED TO CONTINUE EASTWARD
AS THE VORT MAX PUSHES EAST AS WELL. LATEST RUC13 AND NAM12
DEPICTING THE NEXT RIPPLE/VORT MAX APPROACHING NW ZONES BTWN 21Z AND
00Z MON. A FEW SHOWERS ALREADY POPPING UP NEAR FRONT ACROSS NC KY
AND SW OHIO NEAR FRONTAL ZONE. WILL MOST LIKELY INCREASE PRECIP
CHANCES ACROSS THE WESTERN ZONES BY MID/LATE AFTERNOON TO CHANCE TO
ACCOUNT FOR POTENTIAL ACTIVITY PUSHING INTO THE NW ZONES. NOT
EXPECTING MUCH IN THE WAY OF SEVERE POTENTIAL WITH THIS ACTIVITY BUT
A FEW OF THESE COULD BE ON THE STRONGER SIDE. MEANWHILE ALSO EXPECT
SHOWERS AND THUNDERSTORMS TO CONTINUE TO INCREASE IN COVERAGE OVER
SOUTHERN AND SOUTHEAST ZONES WHERE BETTER DEEP LAYER MOISTURE
CONTINUES TO RESIDE.
OVERNIGHT ANY ONGOING CONVECTION SHOULD DISSIPATE RAPIDLY WITH THE
LOSS OF DAYTIME HEATING...WITH THE CONVECTION NO LONGER TIED TO THE
SFC FRONT WHICH IS PROGGED TO REMAIN WEST WITH THE APPROACH OF A SFC
LOW OVER SOUTHERN GREAT LAKES. EXPECT LOWLANDS TO BE DRY BY 06Z
MON...AND REMOVED POPS FOR ALL LOCATIONS BY 09Z MON. CLOUDS WHICH
WILL INITIALLY ATTEMPT TO SCATTER INTO A MOSTLY CLEAR TO PARTLY
CLOUDY SKY EARLY ON MAY REFORM INTO A LOW STRATUS DECK...PARTICULARLY
OVER THE WV LOWLANDS WHERE DEWPOINTS REMAIN RELATIVELY HIGH...WITH
NAM12 BUFKIT SOUNDINGS INDICATING COMPLETE SATURATION UP TO AROUND
700FT AGL WITH SLIGHTLY STRONGER WINDS AT 925MB CREATING SOME
OVERTURNING. RECENT RUC13 SOUNDING LESS ROBUST ON THIS SATURATED
LAYER...SO STRATUS DECK STILL SOMEWHAT IN QUESTION. EITHER
WAY...STILL EXPECT THE USUAL VALLEY FOG AND HAZE AS WELL.
MONDAY...THE AREA STARTS OFF DRY WITH INITIAL ZONAL FLOW. HOWEVER AS
HAS BEEN THE CASE AS OF LATE...FLOW QUICKLY RETURNS TO THE W/SW BY
18Z MON AS THE NEXT S/W TROUGH AND VORT MAX QUICKLY DIVES AROUND THE
BASE OF THE LONGWAVE TROUGH INTO THE LOWER AND MID OHIO RIVER VALLEY
DURING THE AFTERNOON HOURS. EARLY MORNING CLOUDS IN PLACE SHOULD
SLOWLY ERODE BY MID TO LATE MORNING AND LEAVE BEHIND A GENERALLY
PARTLY CLOUDY SKY BY EARLY AFTERNOON. WILL BRING IN SLIGHT CHANCE TO
LOW CHANCE POPS BY THE AFTERNOON HOURS FROM WEST TO EAST BUT EXPECT
THE BULK OF THE PRECIP TO HOLD OFF UNTIL THE EVENING HOURS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
MULTIPLE VORTICITY MAXIMA RIPPLE INTO THE OHIO VALLEY MONDAY AHEAD
OF A COLD FRONT MOVING INTO THE SOUTHERN GREAT LAKES. WILL GET
DECENT FRONTOGENESIS FROM THESE FEATURES...FOLLOWED NEARLY
SEAMLESSLY BY THE COLD FRONT ITSELF...PROVIDING THE MAIN SOURCE FOR
THE LIFT. LOW LEVEL FLOW BACKS TO THE SOUTHWEST...WITH A RETURN OF
THE MOISTURE FROM THE BRIEF PERIOD OF DRYING IN AND AROUND THE 850MB
LEVEL. DEEP MOISTURE AHEAD OF THE FRONT WILL BRING ROUNDS OF SHOWERS
AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY...WITH THE FRONT CLEARING
THE MOUNTAINS BY LATE TUESDAY. CLEAR THE POPS TUESDAY NIGHT.
IN THE CONVECTION...PRECIPITABLE WATER VALUES WILL RETURN TO THE
1.50 TO 1.75 INCH RANGE MONDAY...AND CLOSER TO 2.00 INCHES TUESDAY.
DO NOT ANTICIPATE MUCH IN TERMS OF A SEVERE THREAT FOR THE AREA ON
MONDAY OR TUESDAY...ALTHOUGH TUESDAY WILL SEE A LITTLE BETTER
ORGANIZATION TO THE FLOW WITH 0 TO 6 KM BULK SHEAR VECTORS IN THE 30
TO 40 KNOT RANGE.
WITH THE CLEARING OF THE COLD FRONT AND THE HUMID AIRMASS...COOLER
AND DRIER CONDITIONS COME IN FOR MID WEEK. TENDED TO UNDERCUT THE
GUIDANCE NUMBERS JUST A TOUCH GIVEN THE 850MB TEMPERATURES DROPPING
INTO THE UPPER SINGLE DIGITS CELSIUS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BY WEDNESDAY MORNING...THE COLD FRONT SHOULD BE ALREADY EAST OF
THE APPALACHIANS...LEAVING WV AND THE OH VALLEY UNDER A SURFACE
HIGH PRESSURE. CLEAR SKIES...AND COOLER TEMPERATURES AREA EXPECTED
THROUGH THE END OF THE WEEK...SINCE FLOW BECOMES NORTHERLY EARLY
WEDNESDAY THROUGH FRIDAY. THEREFORE...HIGHS WILL STRUGGLE TO REACH
THE MID TO LOWER 80S...WHILE LOWS WILL DEPEND ON EITHER SKIES
CLEAR OR NOT. CLEAR SKIES COULD ALLOW RADIATIONAL COOLING DURING
THE NIGHTS...CAPABLE TO DROP LOW TEMPERATURES INTO THE MID 50S BY
THURSDAY. THE GFS MODEL SUGGEST A SHARP H5 TROUGH APPROACHES FROM
THE WEST FRIDAY NIGHT INTO SATURDAY.
THEREFORE...ADJUSTED POPS...SKY...AND TEMPERATURES. USED THE HPC
GUIDANCE FOR TEMPERATURES AND POPS...WITH SOME TIMING TWEAKING IN
BETWEEN.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
18Z SUNDAY THRU 18Z MONDAY...
SHOWERS WITH A FEW THUNDERSTORMS CONTINUE THIS AFTERNOON MAINLY
ACROSS THE SOUTHERN ZONES...WITH MORE SHOWERS AND THUNDERSTORMS
OVER CENTRAL AND SW OHIO MOVING EASTWARD TOWARDS THE TRI-STATE
AREA AND SE OHIO. EXPECT MAINLY VFR CONDITIONS TO PREVAIL THIS
AFTERNOON...WITH THE EXCEPTION OF BKW WHERE MVFR CIGS SHOULD
PREVAIL WITH PERHAPS SOME INTERMITTENT VFR. SHOULD A SHOWER OR
STORM DIRECTLY IMPACT A TERMINAL...INTERMITTENT MVFR CIGS WITH
MVFR/IFR VIS WILL LIKELY RESULT WITH BRIEF HEAVY RAINFALL.
OVERNIGHT SHOWERS AND THUNDERSTORMS WILL DIMINISH IN COVERAGE AND
INTENSITY WITH MOST LOCATIONS DRY BY 06Z. FOG AND/OR LOW STRATUS
WILL LIKELY FORM AFTER 06Z AND TOWARDS THE DAWN HOURS WITH SKIES
ATTEMPTING TO SCATTER TO MOSTLY CLEAR BY 09Z ACROSS MOST LOWLAND
LOCATIONS WITH ABUNDANT LLVL MOISTURE AND RECENT RAINS. CONDITIONS
ARE EXPECTED TO IMPROVE DURING THE MORNING HOURS AS USUAL...BUT
IMPROVEMENT MAY BE A BIT SLOWER THAN NORMAL AS A POTENTIAL STOUT
LOW STRATUS DECK MAY BE A BIT STUBBORN TO SCATTER.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: REDEVELOPMENT OF CONVECTION THIS AFTERNOON
AND EVENING COULD VARY. TIMING OF ONSET FOG TONIGHT AND
IMPROVEMENT OF FLIGHT CONDITIONS EARLY MON MORNING MAY 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.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY M M M M M M M H H M L L
HTS CONSISTENCY M M M H H H H H H M L L
BKW CONSISTENCY H H H H M M M M M H H H
EKN CONSISTENCY H H H H H H M H H M L L
PKB CONSISTENCY H H H H H H H H H M L L
CKB CONSISTENCY H H H H H H H H H M M L
AFTER 18Z MONDAY...
IFR POSSIBLE IN FOG/LOW STRATUS MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26/50
NEAR TERM...50
SHORT TERM...26
LONG TERM...ARJ
AVIATION...50
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
442 PM EDT SUN AUG 11 2013
.SYNOPSIS...
GRADUAL UPPER-LEVEL TROUGH AMPLIFICATION IS EXPECTED EARLY THIS
WEEK OVER THE GREAT LAKES REGION AND ADJACENT OHIO VALLEY/NORTHEAST
STATES. THE MEAN UPPER TROUGHING WILL PERSIST THROUGH THE SECOND
HALF OF THE WEEK...KEEPING TEMPERATURES BELOW NORMAL. A COLD FRONT
WILL BE THE FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS AS IT
CROSSES THE REGION ON TUESDAY. CANADIAN HIGH PRESSURE WILL PROVIDE
FAIR WEATHER AND COOL/DRY CONDITIONS FROM WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
MOST OF THE MID DECK OF CLOUDS HAS EITHER MOVED EAST OR
DISSIPATED. THE LOW-LEVEL MOISTURE HAS PRODUCED BANDS OF FAIR
WEATHER CUMULUS OVER MUCH OF THE NORTHERN AND CENTRAL AREAS. RADAR
SHOWS A FEW ENHANCED ELEMENTS...WEAK SHOWERS MAINLY EAST OF ALTOONA.
THE FEW SHOWERS AND ENHANCED CLOUDS OVER THE SOUTHWEST ARE IN THE
MODEST TONGUE OF HIGHER THETA-E AIR NOISING UP FROM THE PANHANDLE
OF WV. THERE IS A LARGE SCALE THETA-E GRADIENT...WELL DEFINED AT
1000 HPA DRAPED ACROSS SOUTHEAST PA NORTH OF ALTOONA THEN WEST
INTO OHIO. BEST ISOLATED SHOWERS WILL BE IN THE SOUTHWEST IN THAT
SLIVER OF HIGH THETA-E AIR.
SHOULD BE QUITE COMFORTABLE THROUGH THIS EVENING WITH TEMPERATURES
RANGING 70 TO LOWER 80S IN SOUTHEAST AND DEW POINTS MAINLY IN
UPPER 40 TO MID 60S.
OVERNIGHT MODELS AND HIGH RESOLUTION MODELS SHOW ISOLATED
CONVECTION AND NO ORGANIZATION. THE 4KM NAM ACTUALLY DEVELOPS A
SMALL MCS...PROBABLY OUT OF THE WAVES OVER MICHIGAN THIS
AFTERNOON...AND BRINGS THE SYSTEM INTO WESTERN PA BY 0500 UTC AND
WEAKENS IT AS IT MOVES INTO SE PA AND DIES A SLOW DEATH NEAR
HARRISBURG. SO KEPT POPS MAINLY SLIGHT CHANCE AFTER MIDNIGHT.
THE RAP AND 4KM NAM PULL SOME OF THE WARMER AIR NORTHWARD TONIGHT
AND THE BOUNDARY GETS INTO N-CENTRAL PA. BEST CHANCE WOULD BE
ALONG AND SOUTH OF BOUNDARY IN MODELS AND BEST FORCING AFTER 0600
UTC WOULD BE SW PA.
OVERNIGHT LOWS MAINLY UPPER MID-50S TO MID 60S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
SREF/GEFS FROM 15 AND 12 UTC SEEM TO SHOW LIGHT RAIN AMOUNTS WHICH
THIS TIME OF YEAR SHOW A WET BIAS. WILL BE WARMER AND MOISTURE
MONDAY SO CANNOT RULE OUT SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. BUT NOTHING IMPLIES A BIG RAIN POTENTIAL AS PW
VALUES ARE STILL LOW.
PREVIOUS DISCUSSION:
SOME CLOUDS/SPOTTY LGT SHOWERS MAY BE LINGERING OVR ERN
SXNS PER MDL CONS EARLY TOMORROW. THE SFC-850MB FLOW WILL SHIFT TO
THE WSW AHEAD OF POLAR FRONT PUSHING SEWD FROM THE GRT LKS REGION.
GRADUAL HGT FALLS ARE EXPECTED TO OCCUR IN ASSOCIATION WITH
UPPER TROUGH DIGGING SEWD ACRS NRN ONTARIO INTO NW QUEBEC...WITH
INCREASINGLY STRONG CYCLONIC UPPER FLOW OVERSPREADING THE GRT LKS
REGION AND ADJACENT OH VLY. THE BEST LLVL MSTR FLUX AND CAPE IS
PROGGED IMMEDIATELY AHEAD OF THE COLD FRONT OVER PORTIONS OF THE
MIDWEST/LWR LKS/UPPER OH VLY DURING THE AFTN...WITH TSTMS EXPECTED
TO INCREASE/INTENSIFY AS BLYR DESTABILIZES. NOT EXPECTING OUR AREA
TO BE IMPACTED UNTL LATER AROUND MID/LATE EVE...AS STORMS SPREAD
SEWD. THE DAY 2 SEE TEXT/5 PCT SVR PROBS INCLUDE THE NW AND NCNTRL
ZONES...HOWEVER ANY STORMS THAT REACH THIS AREA SHOULD BE OF A
WEAKENING CONVECTIVE INTENSITY.
WILL KEEP SCHC POPS FOR THE DAYTIME HOWEVER EXPECT ANY CONVECTION
TO BE ISOLD AT BEST. HIGHEST POPS /LKLY CATG OR 60-70 PCT/ ARE
OVER THE NW ZONES TOMORROW NIGHT. PRE-FRONTAL WSWLY FLOW SHOULD
ALLOW TEMPS TO CLIMB A FEW TO SEVERAL DEGS WARMER THAN TODAY WITH
HIGHS RIGHT AROUND NORMAL FOR THIS TIME OF YEAR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
GENERALLY COSMETIC CHANGES MADE TO PREVIOUS EXTENDED FORECAST
TODAY AS PATTERN WILL BE DOMINATED BY THE ROCKY MOUNTAIN UPPER
RIDGE AND DOWNSTREAM LONG WAVE TROF FROM EASTERN CANADA TO THE MID
ATLANTIC REGION THIS WEEK.
BEST CHANCE OF PRECIPITATION WILL COME FROM A FRONTAL SYSTEM
MONDAY NIGHT AND TUESDAY BEFORE THE MEAN UPPER TROF AXIS SETTLES
EAST OF THE AREA FOR THE LATTER HALF OF THIS WEEK. AS PREVIOUSLY
MENTIONED...THE BIGGEST IMPACT WILL BE A FRESH SHOT OF DRIER AND
COOLER AIR FOR THE MIDDLE OF THE WEEK AS TEMPERATURES DROP BELOW
AVERAGE ON WED AND THU. FLOW BEGINS TO TURN SW LATE IN THE PERIOD
FOR SOME MODERATION AS THE WEEKEND APPROACHES.
LATE IN THE PERIOD...WESTERN ATLANTIC UPPER RIDGE RETROGRADES AND
AMPLIFIES OVER BERMUDA. THIS WILL HELP TO SHARPEN THE EAST COAST
TROF AXIS AND DIRECT DEEPER LAYER MOISTURE NORTHWARD INTO THE MID
ATLANTIC REGION NEXT WEEKEND. HAVE INTRODUCED SHOWER CHANCES AS A
RESULT...MAINLY ON SUNDAY. GULF COAST TROPICAL DEVELOPMENT IS
POSSIBLE WITH THIS SURGE OF MOISTURE...SO WE`LL BE WATCHING THIS
WITH INTEREST AS THE WEEK PROGRESSES.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
VFR CONDS WILL PREVAIL THRU THE AFTN. COSPA DATA SUGGESTS AN
ISOLD SHOWER/TSTM IS PSBL OVER THE SCNTRL TERMINALS...BUT
PROBABILITY/COVERAGE IS TOO LOW TO INCLUDE IN TAFS ATTM. SOME LOW
CLOUDS AND FOG ARE PSBL TNT INTO MONDAY MORNING...AND HAVE ADDED
BR/VCFG AND RESTRICTED VIS WITH THE 18Z ISSUANCE. CONFIDENCE IN
IFR IS MEDIUM GIVEN FAIRLY GOOD AGREEMENT AMONGST THE GUIDANCE.
WILL MAINTAIN REGULAR TAF AT BFD USING TOTAL OB CONCEPT...AND THE
FACT THAT THERE IS NO SIG WX. IF THE OUTAGE CONTINUES INTO TONIGHT
LATER ISSUANCES MAY INCLUDE AMD NOT SKED GIVEN THE PROSPECT OF FOG
AND LOW CIGS OVERNIGHT.
OUTLOOK...
MON...VFR. SHOWERS/TSTMS LKLY OVER THE NW AIRFIELDS MON NGT.
TUE...VFR/MVFR WITH SCT SHOWERS AND TSTMS.
WED-THU...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...ROSS/DEVOIR
AVIATION...STEINBUGL
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
320 PM CDT SUN AUG 11 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 317 PM CDT SUN AUG 11 2013
SURFACE BOUNDARY HAS SET UP FROM NEAR YANKTON SOUTH DAKOTA
NORTHEASTWARD TO CANTON AND EAST TO SPENCER. AIRMASS REMAINS WARM
AND UNSTABLE SOUTH OF THIS BOUNDARY WHERE TEMPERATURES HAVE ALREADY
RISEN INTO THE LOWER 80S WITH DEWPOINTS NEAR 70. RAP SOUNDINGS
SUGGEST THAT MUCAPE VALUES ARE OVER 2000 J/KG WITH EFFECTIVE SHEAR
NEAR 25 TO 35 KT IN THIS AREA. WITH CONTINUED DESTABILIZATION AND
VERY LITTLE CAPPING INDICATED...SCATTERED STORMS ARE EXPECTED TO
DEVELOP ACROSS THE SOUTHEASTERN CORNER OF THE FORECAST AREA WITHIN
THE NEXT FEW HOURS. STRATUS FIELD ENCOMPASSING THE BULK OF THE
FORECAST AREA COULD KEEP THE FOCUS JUST SOUTH OF THE FORECAST AREA
WHERE MID LEVEL LAPSE RATES ARE A BIT MORE IMPRESSIVE AND A LARGE
CUMULUS FIELD CAN BE SEEN ON SATELLITE.
WITH THE SURFACE LOW SLOWLY EDGING EASTWARD THROUGH THE
EVENING...THE BOUNDARY SHOULD BEGIN TO ADVANCE EASTWARD AND IS
EXPECTED TO EXIT THE FORECAST AREA BY AROUND 03Z. IF STORMS MANAGE
TO DEVELOP WITHIN OUR CWA...A FEW SEVERE STORMS WILL BE POSSIBLE AND
WILL POSE A THREAT OF HAIL UP TO GOLF BALLS AND 60 MPH WIND GUSTS.
PRECIPITABLE WATER VALUES REMAIN QUITE HIGH AT 1.5" OR HIGHER...SO
HEAVY RAINFALL WILL ALSO BE LIKELY WITH WITH SHOWERS AND STORMS.
STRATUS NEAR THE BOUNDARY WILL ALSO GRADUALLY BEGIN TO CLEAR OUR
FROM NORTHWEST TO SOUTHEAST THROUGH THIS EVENING BEHIND THIS
SYSTEM...BUT COULD BECOME HUNG UP NEAR THE MISSOURI VALLEY AND SOUTH
CENTRAL IOWA NEAR THE BAGGY PORTION OF THE FRONT. MONDAY WILL BE
ANOTHER PLEASANT LATE SUMMER DAY WITH RELATIVELY LIGHT WINDS AND
SLIGHTLY BELOW NORMAL TEMPERATURES AND PARTLY CLOUDY SKIES. HIGHS
WILL BE IN THE MID 70S TO LOWER 80S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 317 PM CDT SUN AUG 11 2013
MONDAY NIGHT THROUGH WEDNESDAY LOOKS TO STAY MAINLY DRY OVER THE
AREA AS WE REMAIN IN BETWEEN A DIGGING TROUGH TOWARDS THE EAST COAST
AND A BUILDING RIDGE WEST OF THE ROCKIES. HIGH PRESSURE DROPPING OUT
OF CANADA TO OUR EAST...WILL KEEP COOL EASTERLY FLOW OVER US...AND
SHOULD ALSO KEEP MOST OF THE INSTABILITY SOUTH AND WEST OF OUR CWA.
WOULD EXPECT DAILY ISOLATED TO SCATTERED STORM DEVELOPMENT IN THE
WESTERN PLAINS WHERE THE SOUTHEASTERLY UPSLOPE FLOW...CONVERGENCE
AND INSTABILITY ARE MAXIMIZED. HOWEVER THINK MOST OF THAT ACTIVITY
WILL STAY OUT OF OUR AREA. THE EXCEPTION COULD BE IN THE FAR
SOUTHWEST CORNER OF OUR CWA...TOWARDS GREGORY COUNTY...WHICH IS
CLOSE ENOUGH TO THIS ACTION TO WARRANT A LOW CHANCE POP EACH DAY AND
NIGHT. NAM IS A BIT MORE AGGRESSIVE WITH CONVECTION ALONG THE
MISSOURI RIVER AND WEST OF THE JAMES RIVER MONDAY NIGHT INTO
TUESDAY. IT IS FURTHER EAST WITH THE 850 MB BOUNDARY...ALLOWING
CONVERGENCE AND INSTABILITY TO CREEP FURTHER NORTHEAST. BUT SINCE IT
IS A PRETTY BIG OUTLIER AT THIS TIME...WILL STICK CLOSER TO THE
ECMWF AND GFS SOLUTIONS. LOWS MONDAY NIGHT AND TUESDAY NIGHT
DEPENDENT ON CLOUD COVER...BUT AT THIS POINT THINKING WE SEE ENOUGH
CLEARING TO GET SOME COOL LOWS EAST OF THE JAMES RIVER...WITH LOW
AND MID 50S EXPECTED. HIGHS TUESDAY AND WEDNESDAY WILL STAY BELOW
NORMAL...WITH MID AND UPPER 70S COMMON.
BY WEDNESDAY NIGHT THE RIDGING BEGINS TO PUSH NORTHEAST CLOSER TO
THE AREA AS OUR HIGH PRESSURE MOVES OFF TO THE EAST. THIS WILL ALLOW
LOW LEVEL SOUTHEASTERLY WINDS TO MOVE FURTHER INTO THE
AREA...ALLOWING FOR A SLOW INCREASE IN INSTABILITY. THIS WILL ALSO
ALLOW FOR NIGHTLY INCREASES IN THE LOW LEVEL JET WHICH SHOULD ACT TO
HELP INCREASE OUR PRECIP CHANCES. WEDNESDAY NIGHT MAY SEE SOME
ACTIVITY MAKE IT CLOSE TO INTERSTATE 29...AND BY THURSDAY INTO
THURSDAY NIGHT WE MIGHT BE ABLE TO GET SOME CONVECTION ACROSS THE
CWA. INSTABILITY STILL ON THE LOW SIDE AND FORCING NOT THAT
IMPRESSIVE...SO ONLY LOW CHANCE POPS WARRANTED AT THIS TIME. AS THE
RIDGING CONTINUES TO SLOWLY BUILD IN...STARTING TO LOOK LIKE FRIDAY
INTO THE WEEKEND WILL STAY DRY...WITH A WARMING TREND EACH DAY.
THURSDAY WILL SEE MID 70S TO NEAR 80...WITH READINGS NEAR 80 TO 85
OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1239 PM CDT SUN AUG 11 2013
SCATTERED MVFR CEILINGS NEAR THE STALLED BOUNDARY EXTEND ACROSS
SOUTHWEST MINNESOTA INTO MUCH OF SOUTHEAST SD. THESE CLOUDS WILL
SLOWLY SHIFT EASTWARD DISSIPATE THROUGH AROUND 00Z AS THE FRONT
DRIFTS SOUTHEAST. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO FIRE THIS AFTERNOON ALONG AND AHEAD OF
THE BOUNDARY...MAINLY SOUTH OF A VERMILION SD TO SPIRIT LAKE IA LINE.
IFR VISIBILITY AND LOW CEILINGS WILL BE POSSIBLE IN STORMS. A FEW
STRONG TO SEVERE STORMS WILL BE POSSIBLE FROM 21Z TO 03Z. WITH
SEVERAL MODELS INDICATING RATHER LIGHT WINDS OVERNIGHT AND GIVEN THE
RECENT HEAVY RAINFALL...ADDED SOME LOWER VISIBILITY AFTER 10Z IN HON
AND FSD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...CHENARD
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1242 PM CDT SUN AUG 11 2013
.DISCUSSION...UPDATED FOR THE 18Z AVIATION DISCUSSION.
&&
.AVIATION...CONVECTION IS SLOW TO DEVELOP...BUT STARTING TO SEE
MORE DEVELOPMENT WITH ADDITIONAL HEATING. SIMILAR SET UP TO
YESTERDAY...WITH MOST ACTIVITY DEVELOPING ALONG THE SEA BREEZE
AFFECTING CRP-VCT-ALI BETWEEN 18Z-22Z...THEN LRD BTWN 22Z-00Z.
BRIEF MVFR VSBY/CIGS IN AND AROUND ANY THUNDERSTORMS...WITH GUSTY
WIND. OTHERWISE VFR THROUGH THE EVENING. REDEVELOPMENT OF STRATUS
AND FOG IS EXPECTED EARLY MONDAY...HOWEVER MVFR CONDITIONS WERE
VERY BRIEF AND PATCHY SO WILL NOT MENTION AT THIS TIME WITH THE
EXCEPTION OF VCT. AS FOR WINDS...GENERAL 10-15KT E-SE WINDS THIS
AFTERNOON...BECOMING LIGHT AND VARIABLE OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 1042 AM CDT SUN AUG 11 2013/
DISCUSSION...UPDATED HOURLY GRIDS TO REFLECT TRENDS. THE BULK OF
THE SHOWER AND THUNDER ACTIVITY REMAINS WELL SOUTH OF THE CWA...AS
THE UPPER LOW IS POSITIONED FARTHER SOUTH THAN EXPECTED. HOWEVER
MODELS CONTINUE TO SHIFT THE LOW AND THE ASSOCIATED SURFACE
COASTAL TROUGH WEST ACROSS THE REGION. WITH AN UNSTABLE AIRMASS
AND LITTLE TO NO CAPPING...WILL CONTINUE TO EXPECT COVERAGE TO
FILL IN THROUGH THE EARLY AFTERNOON...WITH BETTER DEVELOPMENT OVER
LAND ALONG THE SEA BREEZE. ACTIVITY SHOULD DIMINISH THIS LATE
AFTERNOON/EARLY EVENING WITH THE LOSS OF HEATING.
PREV DISCUSSION... /ISSUED 630 AM CDT SUN AUG 11 2013/
DISCUSSION...SEE 12Z AVIATION DISCUSSION.
AVIATION...PRETTY MUCH NO CHANGE IN THE TIMING OF THE CONVECTION
AS THAT STILL LOOKS GOOD. ANOTHER ROUND OF SCATTERED CONVECTION
EXPECTED TODAY...AND PRETTY MUCH KEPT TIMING OF THE TEMPOS WITH
VCTS STARTING ABOUT AN HOUR BEFORE TEMPO AND ENDING ABOUT ONE HOUR
AFTER TEMPO ENDS. SOME MORNING MVFR BR AND HAVE INCLUDED IN KALI
AND KVCT BUT CANNOT RULE OUT IT OCCURRING IN KCRP AND KLRD.
OTHERWISE...VFR CONDITIONS OUTSIDE OF CONVECTION. WINDS AGAIN
START OFF LIGHT AND VARIABLE THIS MORNING...GRADUALLY VEERING
DURING THE DAY/AFTERNOON AND BECOMING SOUTHEAST GENERALLY LESS
THAN 11 KNOTS (OUTSIDE OF THUNDER). WINDS BECOME VERY LIGHT AOB
06Z...AND COULD HAVE FOG AGAIN AT KVCT AND KALI BEFORE END OF
TERMINAL FORECAST. HELD OFF AT KALI BUT PUT 5SM BR AT KVCT ABOUT
09Z. NO RAINFALL FORECAST FOR THE OVERNIGHT PERIOD.
PREV DISCUSSION... /ISSUED 346 AM CDT SUN AUG 11 2013/
SHORT TERM (TODAY THROUGH MONDAY)...ANOTHER SHOT AT SCATTERED
SHOWERS AND THUNDERSTORMS TODAY AS MOISTURE REMAINS IN PLACE AND
UPPER LOW MOVES TOWARD AREA (AS SEEN ON H20 IMAGERY). HAVE PRETTY
MUCH KEPT POPS AS-IS FOR TODAY AND TONIGHT...AS THESE SEEM
REASONABLE AND 4 KM HRRR IS SHOWING SCATTERED CONVECTION INLAND
AREAS TODAY. FOR MONDAY...MOISTURE DECREASES A TAD AND MODELS WEAKEN
UPPER LOW...SO AM GOING TO KEEP THE POPS LOW FOR NOW. DID BUMP THEM
TO 30 POPS OVER THE EXTREME SOUTHEAST MORE PROXIMATE TO WEAKENING
UPPER LOW. TEMPERATURES WERE A BIT WARMER YESTERDAY THAN EXPECTED
OVER MANY LOCATIONS...SO AM GOING TO GO CLOSE TO PERSISTENCE GIVEN
THE FACT THAT SIMILAR AREAL COVERAGE IS EXPECTED TODAY (EXCEPT OUT
WEST WHERE THINK THERE WILL BE MORE CLOUDS TODAY THAN YESTERDAY THUS
AM GOING TO GO JUST A BIT COOLER). GO A BIT WARMER ON MONDAY WITH
LESS RAIN AND CLOUDS IN THE AREA. ONCE AGAIN HEAT INDICES 105 OR
HIGHER WILL BE MORE ISOLATED AND GENERALLY LESS THAN 2 HOURS SO WILL
HOLD OFF ON ANY SPS TODAY (PUT IN HWO). DITTO ON MONDAY.
MARINE (TODAY THROUGH MONDAY)...GENERALLY WEAK TO MODERATE EAST
FLOW TODAY BECOMING SOUTHEAST BY TONIGHT AND CONTINUING ON MONDAY.
SCATTERED SHOWERS/STORMS TODAY...WITH LESS ACTIVITY MONDAY GIVEN
LOWER MOISTURE...WITH MORE CONVECTION LIKELY OVER THE SOUTHERN AREAS
MORE PROXIMATE TO UPPER LOW.
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...HIGH PRESSURE BUILDS
BACK IN FOR THE MIDDLE OF THE WEEK AS UPPER LEVEL LOW SHIFTS TO THE
WEST. THIS WILL LEAD TO DRY AND HOT CONDITIONS ACROSS SOUTH TEXAS
THROUGH THURSDAY. AS THE UPPER RIDGE THEN SHIFTS WESTWARD A TROUGH
DIGS ACROSS THE EASTERN HALF OF THE COUNTRY...BECOMING SURPRISINGLY
AMPLIFIED BY FRIDAY/SATURDAY PERIOD. AT THE SURFACE MODELS DEPICT A
WEAK COLD FRONT INTO CENTRAL TEXAS THURSDAY/FRIDAY. PREVIOUSLY
QUESTIONED THIS FRONT MAKING IT INTO SOUTH TEXAS THIS TIME OF
YEAR...BUT STARTING TO THINK IT MAY BE A POSSIBILITY. HAVE ALLOWED
WINDS TO BACK A BIT MORE FRIDAY WITH THE APPROACHING FRONT. MOISTURE
NOT TOO IMPRESSIVE AT THIS POINT...AND WILL JUST STICK WITH 20 POPS
IN THE NORTHEAST FOR NOW. IF THE FRONT DOES GET INTO THE
AREA...WOULD EXPECT MORE CLOUDS...AND SLIGHTLY COOLER
TEMPERATURES...BUT PROBABLY NOT MORE THAN A COUPLE OF DEGREES.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 95 78 96 78 97 / 40 10 30 10 10
VICTORIA 97 75 98 76 98 / 40 10 20 10 10
LAREDO 99 79 100 79 103 / 20 10 10 10 10
ALICE 97 76 98 76 100 / 40 10 20 10 10
ROCKPORT 92 79 93 80 92 / 30 20 20 10 10
COTULLA 100 76 100 76 103 / 10 10 10 10 10
KINGSVILLE 96 76 97 77 99 / 40 10 20 10 10
NAVY CORPUS 91 79 91 79 92 / 30 20 30 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...AVIATION
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
345 PM CDT SUN AUG 11 2013
.SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM.
A FEW SHOWERS AND THUNDERSTORMS HAVE BEEN PERSISTENT ALONG THE MN/IA
BORDER TODAY. THEY ARE COINCIDENT WITH DEEP LAYER MOISTURE FLUX
CONVERGENCE... 850MB FRONTOGENESIS... WEAK DIFFERENTIAL VORTICITY
ADVECTION... AND UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT ENTRANCE
REGION OF THE UPPER JET. THESE FEATURES WILL SLOWLY TRACK EASTWARD
ACROSS SOUTHERN WISCONSIN TONIGHT. IN ADDITION...A DECENT SURFACE
BAROCLINIC ZONE HAS SET UP OVER SOUTHERN WI DUE TO THE EXTENSIVE
CLOUD COVER. THERE IS A TIGHT TEMPERATURE GRADIENT RIGHT ALONG THE
WI/IL BORDER.
THE HRRR AND OTHER MESOSCALE MODELS ARE ALL CURRENTLY OVERDOING THE
PRECIP GOING ON IN IA/MN RIGHT NOW...SO LOW CONFIDENCE IN THEIR
PREDICTION OF WIDESPREAD COVERAGE FOR TONIGHT. NONETHELESS...THERE
IS ENOUGH PERSISTENT FORCING TO HAVE LIKELY SHOWERS AND ISOLATED
THUNDER IN THE FORECAST ACROSS SOUTHERN WI...MAINLY ALONG AND SOUTH
OF I-94...FOR MOST OF THE NIGHT. CHANCES WILL TAPER OFF FROM WEST TO
EAST AFTER MIDNIGHT.
FOG IS LOOKING LIKELY FOR TONIGHT. ORIGINALLY...A COLD FRONT WAS
GOING TO BE DROPPING DOWN TONIGHT...BUT THAT IS LOOKING DELAYED
UNTIL TOMORROW NOW. WINDS WILL BE LIGHT AND THERE IS ADDED LOW LEVEL
MOISTURE FROM THIS MORNING/S RAIN OVER ALL OF SOUTHERN WISCONSIN.
WITH DEWPOINT TEMPS SITTING IN THE LOWER 60S...EXPECTING A SMALL
SPREAD TONIGHT. DENSE FOG WILL BE POSSIBLE...ALTHOUGH THAT WOULD
REQUIRE A PERIOD OF CLEAR SKIES. NOT SURE HOW FAR SOUTH THAT
NORTHERN EDGE OF THE CLOUD SHIELD WILL SINK TONIGHT... SO NOT
CONFIDENT ENOUGH TO ISSUE A DENSE FOG ADVISORY FOR ANY PARTICULAR
AREA AT THIS TIME.
MONDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
A COLD FRONT WILL DROP DOWN ACROSS SOUTHERN WI ON MONDAY. IT LOOKS
LIKE IT WILL COME IN TWO WAVES...WITH A WEAK SURFACE FRONT WITH
WINDS BECOMING NORTH EARLY MONDAY MORNING...AND THEN A PUSH OF
COLDER AIR LATE MONDAY AFTERNOON. THAT SECOND PUSH IS EXPECTED TO
RUSH DOWN THE LAKE A LITTLE FASTER THAN INLAND...ALSO KNOWN AS A
BACK DOOR COLD FRONT...AND BRING SOME STRONGER WINDS WITH IT.
THERE WILL BE STEEP LOW LEVEL LAPSE RATES AND CYCLONIC FLOW ALOFT
WHICH WILL HELP CLOUDS DEVELOP DURING THE DAY. THERE MAY BE JUST
ENOUGH MOISTURE AROUND IN THE EASTERN MKX FORECAST AREA TO ALLOW FOR
SCATTERED SHOWERS. WHILE THE CHANCE IS SMALL...THERE COULD BE A FEW
RUMBLES OF THUNDER AS WELL. CLOUDS WILL KEEP EASTERN MKX AREA A
LITTLE COOLER IN THE MID 70S...WHILE BREAKS IN THE CLOUDS SHOULD
ALLOW WESTERN AREAS TO WARM UP TO AROUND 80.
.LONG TERM...
MONDAY NIGHT - CONFIDENCE...MEDIUM
SHORT-WAVE TROUGH SWINGS SOUTHEAST THROUGH MY COUNTY WARNING AREA
MONDAY NIGHT. NORMALLY...ONE WOULD THINK OF HAVING AT LEAST A LOW-
CHANCE PROBABILITIES OF MEASURABLE PRECIP WITH A TROUGH.
HOWEVER...MODELS DON/T SHOW MUCH MOISTURE ABOVE 10 THSD FT AGL IN
THE TIME SECTIONS. IN FACT THEY SHOW DRYING TO VARYING DEGREES.
WITH THE LACK OF SATURATION IN THE -10 TO -20C LAYER OF
AIR...CAN/T SEE PRECIPITATION. THE NAM/ECWMF HAVE MY CWA DRY...AND
GFS SPITS OUT A COUPLE SHOWERS. WILL KEEP FORECAST DRY.
TUESDAY THROUGH THURSDAY - CONFIDENCE...MEDIUM
LARGE COOL HIGH PRESSURE DROPS SOUTHEAST TROUGH GREAT LAKES REGION.
QUIET WEATHER. CAN SEE SOME FOG IN RIVER VALLEYS...SO PUT THAT INTO
THE GRID FORECASTS. THE NAM/GFS MODELS SUGGEST ISOLATED SHOWERS
TUESDAY THROUGH THURSDAY WITH HEATING DURING THE DAY. THIS LOOKS TO
TO SOME KIND OF NOISE SINCE THE BUFKIT SOUNDINGS SHOW A PERSISTENT
SUBSIDENCE INVERSION BETWEEN 10 AND 15 THSD FT DURING THIS TIME THAT
CAPS ANY MIXED BOUNDARY LAYER AIR FROM RISING UPWARD. SO WILL KEEP
DRY DURING THIS PERIOD.
FRIDAY THROUGH SUNDAY - CONFIDENCE...MEDIUM
GFS SUGGESTS CHANCES FOR PRECIPITATION ON FRIDAY AS A SHORTWAVE
TROUGH AND VORTMAX DROP INTO AND ATTEMPT TO CLOSE OFF OVER SOUTHERN
WISCONSIN. ECMWF IS SIMILAR BUT WEAKER...AND KEEPS THINGS DRY. BOTH
THE GFS AND ECMWF HAVE MID-LEVEL DRY AIR ON FRIDAY...SUGGESTING
MID-LEVEL SUBSIDENCE INVERSION HANGS TOUGH. RATHER THAN YO-YO ON
THE FORECAST...WILL KEEP HOLDING OFF ON CHANCE FOR PRECIPITATION. IT
IS EVEN POSSIBLE THE CLOSING-OFF IDEA WILL OCCUR SOUTH OF WISCONSIN
ANYWAY.
SURFACE HIGH PRESSURE EXTENSION FROM EAST COAST BACK TO ILLINOIS/WI
AREA PER MODEL FORECAST SUGGESTS DRY FOR SATURDAY AND SUNDAY.
&&
.AVIATION/00Z TAFS/...
AN AREA OF SHOWERS WITH A FEW THUNDERSTORMS OVER NORTHERN IOWA WILL
SLOWLY WORK THEIR WAY EASTWARD ACROSS SOUTHERN WI OVERNIGHT. NOT
QUITE CERTAIN ABOUT COVERAGE...BUT THEY SHOULD AT LEAST BE
SCATTERED...IF NOT NUMEROUS. CEILINGS AND VISIBILITIES WILL LOWER
INTO MVFR RANGE WITH AREAS OF FOG AND SCATTERED SHOWERS/THUNDER.
SCATTERED SHOWERS AND ISOLATED THUNDER POSSIBLE ONCE AGAIN MONDAY
AFTERNOON MAINLY EAST OF MADISON WITH A COLD FRONT DROPPING DOWN
ACROSS WISCONSIN.
&&
.MARINE...
A COLD FRONT PUSHES SOUTH MONDAY WITH WINDS TURNING TO THE NORTH AND
THEN NORTHEAST ACROSS LAKE MICHIGAN. PRESSURE RISES ON THE ORDER OF
3 MB/6 HOURS AND DECENT COLD ADVECTION SHOULD KICK UP WINDS AT LEAST
INTO 15 KNOT RANGE. FAVORABLE FETCH MONDAY NIGHT THROUGH TUESDAY
WITH SPEEDS APPROACHING SMALL CRAFT LEVELS SHOULD GENERATE DECENT
WAVES ESPECIALLY FROM MILWAUKEE ON SOUTH. RIGHT NOW LOOKING AT
ABOUT 4 FOOT WAVES LATE MONDAY NIGHT THROUGH TUESDAY AND THESE MAY
LINGER INTO TUESDAY NIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...KAPELA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
248 PM CDT SUN AUG 11 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 248 PM CDT SUN AUG 11 2013
MAIN FORECAST CONCERNS ARE ON PRECIPITATION TONIGHT AND DENSE FOG
POTENTIAL TONIGHT INTO MONDAY MORNING.
CURRENTLY...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER
MUCH OF THE U.S. AND CANADIAN ROCKIES...WHILE TROUGHING DOMINATED
SOUTHEAST CANADA. THE FORECAST AREA RESIDES IN WEST-NORTHWEST
FLOW...WITH SHORTWAVES OF NOTE OVER NORTHEAST IOWA...SOUTHERN
MANITOBA AND A MUCH STRONGER ONE OVER NORTHERN MANITOBA. THE
NORTHEAST IOWA SHORTWAVE...COMBINED WITH A LOW TO MID LEVEL
FRONTOGENESIS ZONE AND A RIGHT ENTRANCE REGION OF AN 80 KT UPPER
JET STREAK IN NORTHERN WI...HAS HELPED TO KEEP SOME SHOWER
ACTIVITY GOING ACROSS NORTHERN IOWA THROUGH THE AFTERNOON. ALSO
PLENTY OF CLOUDS EXIST ACROSS THE FORECAST AREA...RESULTING FROM
DEEP LOW LEVEL MOISTURE SEEN ON THE 12Z MPX SOUNDING AND THE LACK
OF MUCH WIND FLOW TO ADVECT DRIER AIR SEEN ACROSS NORTH DAKOTA AND
NORTHERN MN. THE DRIER AIR LIES BEHIND A SURFACE TROUGH STRETCHING
FROM EASTERN NEBRASKA INTO NORTHWEST WI. A FEW SHOWERS HAVE FORMED
ON THIS TROUGH ACROSS EAST CENTRAL MN. FARTHER SOUTH...A WARM
FRONT ENHANCED BY OUTFLOW FROM THE SHOWERS WAS PRESENT STRETCHING
ALONG US-20 IN IOWA.
SYNOPTIC OVERVIEW...
FOCUS IS MOSTLY ON THE SHORTWAVE OVER NORTHERN MANITOBA. MODELS PROG
THIS SHORTWAVE TO DROP SOUTHEAST INTO UPPER MICHIGAN ON MONDAY. THIS
SHORTWAVE ALLOWS UPPER TROUGHING TO MOVE INTO THE FORECAST AREA...
AND SIMULTANEOUSLY HELPS GIVE THE SURFACE TROUGH IN MN A PUSH
SOUTHEAST. BY 12Z MONDAY...THE TROUGH...LIKELY NOW A COLD
FRONT...SHOULD BE SOUTHEAST OF THE AREA. THERE ARE ALSO
INDICATIONS OF AN INVERTED SURFACE TROUGH LINGERING BACK EXTENDING
NORTHWEST TO SOUTHEAST OVER CENTRAL/EASTERN WI...ASSOCIATED WITH
THAT SHORTWAVE DROPPING INTO UPPER MI.
HAZARDS...
DENSE FOG CONCERNS TONIGHT GIVEN RECENT RAINS...LIGHT WINDS...LATE
DAY CLEARING AND SMALL TEMP/DEWPOINT SPREADS ALREADY.
DETAILS...
SHOWERS IN EAST CENTRAL MINNESOTA MAY TRY TO DROP DOWN INTO
NORTHWESTERN SECTIONS OF THE FORECAST AREA THIS EVENING.
HOWEVER...THEY ARE HIGHLY DIURNALLY DRIVEN...THUS ONCE HEATING
ENDS THEY SHOULD FALL APART QUICKLY. INCLUDED SOME 20 PERCENT
CHANCES FOR THEM FOR A FEW HOURS THIS EVENING. MEANWHILE...TO THE
SOUTH...ONGOING SHOWERS AND STORMS ACROSS NORTHEAST IOWA MAY
PERSIST THROUGH MUCH OF THE EVENING...SUPPORTED BY THE SHORTWAVE
TRACKING ACROSS NORTHEAST IOWA...THE LOW/MID LEVEL F-GEN AND RIGHT
ENTRANCE REGION. HOWEVER...AS THE UPPER FLOW TURNS MORE
NORTHWESTERLY... ANTICIPATING THESE FORCING FEATURES TO DROP
SOUTHEAST AND HELP DIMINISH THE PRECIPITATION. DID KEEP 20-40
PERCENT CHANCES GOING AFTER MIDNIGHT JUST IN CASE PRECIP HOLDS
ON A BIT LONGER THAN EXPECTED.
CONCERN THEN SHIFTS TO FOG GIVEN RECENT RAIN. CLOUDS OVER THE
FORECAST AREA...PARTICULARLY OVER THE NORTHERN HALF...SHOULD CLEAR
OUT THIS EVENING. WINDS LOOK TO STAY FAIRLY LIGHT THROUGH THE
NIGHT...EVEN AFTER THE TROUGH/FRONTAL PASSAGE. ITS WORTH NOTING
THAT WINDS DO PICK UP AT 950MB INTO THE 10-20 KT RANGE BY 12Z...
HOWEVER...THESE ARE ABOVE A 3C FRONTAL INVERSION. THUS...THEY SHOULD
NOT IMPACT THE FOG POTENTIAL MUCH. IN FACT...11.00Z/06Z/12Z HIRES
ARW/NMM AND 11.09Z SREF VISIBILITY PROGS SHOW PRETTY MUCH A SOLID
AREA OF FOG OVER SOUTHEAST MN...NORTHERN PARTS OF IOWA AND MUCH OF
SOUTHERN WI. ADDED MENTION OF FOG EARLIER ACROSS MUCH OF THE
FORECAST AREA...AND NOW HAVE RAISED THE COVERAGE TO WIDESPREAD IN A
CORRIDOR FROM SOUTHEAST MINNESOTA EAST INTO JACKSON...JUNEAU...ADAMS
AND VERNON COUNTIES OF WI. THIS AREA HAS ALSO BEEN INCLUDED IN A
DENSE FOG ADVISORY...SINCE FROM A REGIONAL PERSPECTIVE SEEMS TO
HAVE THE HIGHEST PROBABILITY OF METEOROLOGICAL CONDITIONS
FAVORABLE FOR DENSE FOG. THE ADVISORY MAY HAVE TO BE EXPANDED
SOUTH...ESPECIALLY IF SKIES END UP CLEARING THERE.
FOR MONDAY...COOLER AIR ALOFT UNDER THE UPPER TROUGHING COMBINED
WITH THE INVERTED SURFACE TROUGH...DAYTIME HEATING AND LINGERING LOW
LEVEL MOISTURE SHOULD ALLOW FOR ISOLATED/SCATTERED SHOWERS TO FORM
ALONG/NORTHEAST OF I-94. MLCAPE VALUES ALONG THE INVERTED TROUGH ARE
IN THE 100-300 J/KG AT 18Z...ENOUGH MAYBE TO GET A FEW
THUNDERSTORMS. BETTER INSTABILITY IS OFF TOWARDS SOUTHEAST WI WITH
HELP FROM LAKE BREEZE CONVERGENCE. ONCE THE FOG AND ASSOCIATED LOW
STRATUS MIX OUT A FEW HOURS AFTER SUNRISE...RELATIVELY BREEZY
NORTHWEST WINDS APPEAR TO SET UP. 850MB TEMPS IN THE 10-14C RANGE
SUPPORT HIGHS IN THE MID 70S TO LOW 80S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 248 PM CDT SUN AUG 11 2013
MUCH OF THE ENTIRE LONG TERM PERIOD IS DOMINATED BY RIDGING OVER THE
WESTERN U.S. AND TROUGHING IN THE EASTERN U.S....A POSITIVE PNA
PATTERN THAT RESULTS IN COOLER AND DRIER THAN NORMAL WEATHER. AT THE
SURFACE...CANADIAN HIGH PRESSURE IS PROGGED TO BUILD INTO THE AREA
MONDAY NIGHT AND TUESDAY...SIT OVER THE AREA TUESDAY NIGHT THROUGH
WEDNESDAY...THEN ONLY SLOWLY DRIFT OFF TOWARDS THE EASTERN GREAT
LAKES THIS WEEKEND. DRY AIR ACCOMPANYING THE HIGH LOOKS TO KEEP THE
BULK OF THE LONG TERM PERIOD DRY. IN FACT...PRECIPITABLE WATER
VALUES ARE FORECAST BETWEEN 50-70 PERCENT OF NORMAL FOR TUESDAY
THROUGH THURSDAY. THIS SHOULD RESULT IN DECENT MIXING OF DEWPOINTS
DURING THE AFTERNOONS.
THE ONLY FEATURE REALLY OF INTEREST FOR POTENTIAL PRECIPITATION IS A
SHORTWAVE TROUGH THAT DROPS DOWN THROUGH THE NORTHWEST FLOW INTO THE
AREA THURSDAY NIGHT AND FRIDAY. BOTH THE 11.12Z GFS/CANADIAN PRODUCE
SOME LIGHT PRECIPITATION WITH IT OVER WESTERN AND NORTHERN SECTIONS
OF THE FORECAST AREA...WHEREAS THE 11.00Z/11.12Z ECMWF IS DRY. FROM
A CONSENSUS STANDPOINT...HAVE CONTINUED TO CARRY A 20 PERCENT CHANCE
TO ACCOUNT FOR THE GFS/CANADIAN. HOWEVER...LATER FORECASTS WILL BE
ABLE TO GO DRY IF THE GFS/CANADIAN TREND TOWARDS THE ECMWF.
TEMPERATURE WISE...850MB TEMP ANOMALIES ARE PROGGED TO BOTTOM OUT
BETWEEN 1-1.5C BELOW NORMAL FOR TUESDAY AND WEDNESDAY...READINGS OF
8C EAST TO 10C WEST. THUS THIS WILL BE THE COLDEST PERIOD WITH HIGHS
IN THE 70S. LOWS ARE LIKELY GOING TO DIP INTO THE 40S AT THE TYPICAL
COLD SPOTS TUESDAY NIGHT AND WEDNESDAY NIGHT WITH THE HIGH
OVERHEAD...WHICH WILL ALSO BE THE MOST FAVORABLE TIME PERIODS FOR
VALLEY FOG. VALLEY FOG IS ALSO POSSIBLE MONDAY NIGHT...BUT WINDS
WITH THE INCOMING HIGH MAY RESTRICT SOME OF THE COVERAGE. SLOW
WARMING OF 850MB TEMPS AND ANOMALIES IS FORECAST FOR THURSDAY AND
BEYOND...PEAKING AT 12C EAST TO 15C WEST AND AROUND NORMAL FOR
ANOMALY BY SUNDAY. THUS TEMPERATURES SHOULD SLOWLY CLIMB TOO EACH
DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM CDT SUN AUG 11 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS
THE AREA THIS AFTERNOON INTO EARLY THIS EVENING. THE BULK OF THIS
ACTIVITY WILL OCCUR SOUTH OF INTERSTATE 90...WITH ISOLATED
SHOWERS POSSIBLE AT THE TAF SITES. PLAN ON MVFR CEILINGS AT TIMES
THIS AFTERNOON WITH CLOUD BASES AROUND 1500 FT. CLEARING IS
EXPECTED TO OCCUR FROM THE NORTHWEST TONIGHT AS DRIER AIR MOVES
IN ALOFT. THIS WILL SET THE STAGE FOR DENSE FOG AT THE TAF SITES.
THE ONLY NEGATIVE GOING FOR DENSE FOG IS THE POTENTIAL FOR SOME
LINGERING CLOUDS OVER THE AREA OVERNIGHT. LIFR CONDITIONS ARE
EXPECTED AFTER MIDNIGHT TONIGHT IN DENSE FOG AT BOTH TAF SITES
WITH VISIBILITIES FALLING TO 1/4 MILE OR LESS AT TIMES. THE FOG
SHOULD MIX OUT IN THE 13 TO 14Z TIMEFRAME WITH VFR CONDITIONS
EXPECTED BY THE MID TO LATE MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY FROM 3 AM TO 9 AM CDT MONDAY FOR WIZ032>034-
041>044-053.
MN...DENSE FOG ADVISORY FROM 3 AM TO 9 AM CDT MONDAY FOR MNZ079-
086>088-094>096.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1235 PM CDT SUN AUG 11 2013
.UPDATE...
FIRST WAVE OF LIGHT RAIN ASSOCIATED WITH A SHORTWAVE TROUGH HAS
SHIFTED INTO THE NORTHEAST MKX FORECAST AREA LATE THIS MORNING.
ANOTHER AREA OF SHOWERS WITH A FEW RUMBLES OF THUNDER ALONG THE
MN/IOWA BORDER HAS BEEN MOVING EAST WITH A VERY WEAK SHORTWAVE WITH
SOME SUPPORT FROM DIVERGENCE ALOFT DUE TO A RIGHT ENTRANCE REGION OF
THE UPPER JET. THE LEADING EDGE OF THAT PRECIP IS DISSIPATING AS IT
GETS INTO SOUTHWEST WI...BUT THE BACK EDGE OF IT HAS SUPPORT FROM
850MB FRONTOGENESIS.
THE 15Z HRRR AND 12Z WRF-ARW AND WRF-NMM SHOW THE SOUTH CENTRAL
MN/NORTH CENTRAL IOWA PRECIP TO EXPAND ACROSS SOUTHERN WI THIS
AFTERNOON. THEIR INITIALIZATION LOOKS OVERDONE...SO WILL KEEP THE
LOWER POPS /SCATTERED/ MENTION THROUGH THE AFTERNOON. WEAK
INSTABILITY ALLOWS FOR THUNDER POSSIBILITY.
TEMPS WILL STAY PRETTY COOL TODAY DUE TO THE CLOUD COVER. GOING MAX
TEMPS IN THE LOWER 70S LOOKS ON TRACK.
ONE MORE SHORTWAVE TROUGH DROPS THROUGH THE UPPER MIDWEST THIS
EVENING...ALONG WITH A WESTERLY LOW LEVEL JET AND WEAK UPPER
DIVERGENCE. THEREFORE...NOT GIVING UP ON THE POSSIBILITY FOR ANOTHER
ROUND OF SHOWERS WITH ISOLATED THUNDER THIS EVENING...BUT CONFIDENCE
IS LOW.
&&
.AVIATION/18Z TAFS/...
SHOWERS AND THUNDERSTORMS WILL BE A SMALL THREAT FOR THE AFTERNOON.
THE PRECIP MOVING INTO SOUTHWEST WI NOW IS DISSIPATING.
THERE IS LOWER CONFIDENCE ON HOW THE EVENING PRECIP WILL PAN OUT. IT
MAY BE MORE SCATTERED SHOWERS WITH A FEW THUNDERSTORMS NOW INSTEAD
OF WIDESPREAD SHOWERS AND THUNDERSTORMS. CEILINGS AND VISIBILITIES
WILL LOWER INTO MVFR RANGE PATCHY FOG AND THREAT FOR SHOWERS/THUNDER.
&&
.PREV DISCUSSION... /ISSUED 325 AM CDT SUN AUG 11 2013/
TODAY-FORECAST CONFIDENCE MEDIUM
INITIAL SHORT WAVE TROUGH MOVING THROUGH WITH 20 METER HEIGHT FALLS
EARLY THIS MORNING AND SHOULD BE OVER THE EASTERN GREAT LAKES BY THE
AFTERNOON. COMPLEX DOUBLE UPPER JET STRUCTURE DIFFICULT TO INTERPRET
FORCING DURING THE DAY WITH ONE BRANCH ACROSS LAKES INTO SOUTHERN
QUEBEC AND THE OTHER FROM OHIO VALLEY INTO SOUTHERN NEW ENGLAND.
LOW LEVEL JET IS WEAK AND VEERS TO DUE WEST DURING THE DAY AT ABOUT
20 KNOTS FROM NORTHERN IOWA INTO SOUTHERN WISCONSIN.
ACTIVE CONVECTION FARTHER FAR WEST AND MOST SHORT RANGE AND
MESOSCALE MODEL GUIDANCE KEEPS IT THAT WAY DURING THE DAY. MOSTLY
ANVIL DEBRIS MAKING INTO SOUTHERN WISCONSIN BEFORE LATE AFTERNOON SO
WILL WAIT UNTIL AFTER 18Z TO INTRODUCE THUNDER.
CLOUDS AND PRECIPITATION SHOULD HOLD READINGS DOWN WITH MOST
LOCATIONS STRUGGLING TO REACH THE MIDDLE 70S.
TONIGHT-FORECAST CONFIDENCE HIGH
DEEP UPPER LOW MOVES ACROSS JAMES BAY WITH ASSOCIATED TROUGH DIGGING
SOUTH ACROSS ONTARIO. WIDESPREAD HEIGHT FALLS OF 20 TO 60 METERS
SPREAD OVER GREAT LAKES AS COLD FRONT PUSHES INTO CENTRAL
WISCONSIN. 90 KNOT 250 MB JET MOVES ACROSS LAKE HURON WITH RIGHT
ENTRANCE REGION OVER SOUTHERN WISCONSIN. 850 MB JET INCREASES TO
ABOUT 30 KNOTS OVER SOUTHERN LAKE MICHIGAN DURING THE NIGHT WITH
DECENT WARM ADVECTION AT LOW LEVELS. THUS...APPEARS THAT
THUNDERSTORMS WILL IMPACT MOST OF SOUTHERN WISCONSIN AND ESPECIALLY
SOUTHERN TWO TIERS.
TOUGH TO GET OVERLY EXCITED ABOUT SEVERE POTENTIAL DESPITE DECENT
SHEAR. MODELS HAVE MARGINAL INSTABILITY SO APPEARS THAT LARGE
CONVECTIVE BLOB MOVES THROUGH WITH MARGINAL WIND AND HAIL THREAT PER
SPC OUTLOOK.
MONDAY - CONFIDENCE...MEDIUM
LINGERING SURFACE/850 TROUGH IN THE SE RESULTS IN SHRA CHANCES
ESPECIALLY DURING THE MORNING HOURS. FRONTOGENETICAL FORCING IS WEAK
AND SO IS THE Q-VECTOR CONVERGENCE. RENEWED SHORTWAVE ENERGY ARRIVES
LATER IN THE AFTERNOON WITH AN UPTICK IN FORCING. HOWEVER LOW LEVEL
COLD ADVECTION STARTING TO KICK IN AS WELL. NAM AND GFS BOTH SHOW
LIGHT QPF IN THE 18-00Z TIME FRAME ESPECIALLY IN NE CWA. BUFKIT
SOUNDINGS SHOW CAPE DEVELOPING IN THE AFTERNOON. WILL MAINTAIN THE
GOING CHANCE FOR TSRA POPPING UP IN THE WAKE OF MORNING FRONTAL TYPE
PRECIP.
TUESDAY - CONFIDENCE...MEDIUM
COOLER AIRMASS WITH NE WINDS AND 850 THERMAL TROUGH EXTENDING INTO
ERN WI. YET ANOTHER SHORTWAVE WRAPS INTO WI IN THE NORTHWEST FLOW.
MUCH ONLY THE NAM GENERATES PRECIP WITH OTHER MODELS KEEPING THE
DRIER AIRMASS DOMINANT. THE ECMWF SHOWS DEW POINTS DROPPING INTO THE
U40S/L50S WHICH SEEMS PLAUSIBLE AND WOULD LIMIT THE INSTABILITY.
BUFKIT SOUNDINGS FROM BOTH THE NAM AND GFS SUGGEST COLUMN TOO DRY TO
SUPPORT ANY PRECIP. WILL KEEP FORECAST DRY PER ECMWF/GFS MOS DESPITE
THE FORMIDABLE LOOK TO THE 500 MILLIBAR SHORTWAVE AND SMALLISH POPS
FROM THE NAM.
WEDNESDAY THROUGH SATURDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE WILL BE DOMINANT THIS PERIOD WITH QUIET CONDITIONS.
925 TEMPS COOLEST WEDNESDAY WITH VERY SLOW MODIFICATION INTO
SATURDAY. INFLUENCE OF HIGH KEEPING PRECIP POTENTIAL NEAR NIL. GFS
IS THROWING OUT SOME PRECIP SPLOTCHES HERE AND THERE THOUGH
LEANING TOWARDS THE DRY LOOK OF THE ECMWF.
AVIATION/12Z TAFS/...VFR CONDITIONS EXPECTED MUCH OF THE PERIOD.
PATCHY MVFR FOG MAINLY KENW AREA FIRST THING SHOULD NOT LINGER
VERY LONG. DEBRIS CLOUDS SPREADING IN FROM THUNDERSTORM COMPLEX
ALONG IOWA/MINNESOTA BORDER EARLY TODAY AND SHOULD LINGER INTO
MONDAY.
SHOWERS AND THUNDERSTORMS WILL BE A THREAT FOR NEXT 24 HOURS OR MORE
BUT ESPECIALLY TONIGHT. MOST OF THE ACTIVITY DURING THE DAY SHOULD
BE RELATIVELY LIGHT AND NOT HAVE MUCH IMPACT ON CEILINGS AND
VISIBILITIES. CEILINGS AND VISIBILITIES WILL LOWER INTO MVFR RANGE
FOR A WHILE TONIGHT WITH PERSISTENT PRECIPITATION AND LOCALLY
HEAVIER SHOWERS.
MARINE...COLD FRONT PUSHES SOUTH MONDAY WITH WINDS TURNING TO THE NORTH
AND THEN NORTHEAST ACROSS LAKE MICHIGAN. PRESSURE RISES ON THE ORDER
OF 3 MB/6 HOURS AND DECENT COLD ADVECTION SHOULD KICK UP WINDS AT LEAST
INTO 15 KNOT RANGE. FAVORABLE FETCH MONDAY NIGHT THROUGH TUESDAY WITH
SPEEDS APPROACHING SMALL CRAFT LEVELS SHOULD GENERATE DECENT WAVES
ESPECIALLY FROM MILWAUKEE ON SOUTH. RIGHT NOW LOOKING AT ABOUT 4
FOOT WAVES LATE MONDAY NIGHT THROUGH TUESDAY AND THESE MAY LINGER
INTO TUESDAY NIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...COLLAR
MONDAY THROUGH SATURDAY...CRAVEN