Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/31/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
915 AM MST MON JUL 29 2013
.SYNOPSIS...MOST OF THE AREA WILL SEE A BREAK IN MONSOON STORMS
TODAY AND TUESDAY AS DRIER AIR HAS MOVED ACROSS THE AREA. THE
EXCEPTION WILL BE NEAR THE STATE BORDER WITH NEW MEXICO AND ALONG
THE INTERNATIONAL BORDER FROM NOGALES EAST. THE DAILY CYCLE OF
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL THEN OCCUR
DURING THE LATTER PART OF THIS WEEK AND NEXT WEEKEND. HOTTER DAYTIME
TEMPERATURES WILL OCCUR TODAY THROUGH WEDNESDAY FOLLOWED BY A
COOLING TREND BY NEXT WEEKEND.
&&
.DISCUSSION...SCATTERED TO BROKEN MOSTLY THIN CIRRIFORM CLOUDS FROM
TUCSON EWD WITH MOSTLY CLEAR SKIES ACROSS WRN PIMA COUNTY AT THIS
TIME. DEWPOINTS VALID 16Z RANGED FROM THE MID 40S ACROSS WRN PIMA
COUNTY TO THE MID 60S IN FAR SERN SECTIONS. THESE TEMPS WERE NEARLY
5-15 DEGS F LOWER VERSUS 24 HOURS AGO. 29/12Z KTWC SOUNDING DEPICTED
A FAIRLY DRY PROFILE...AND EVEN DRIER VERSUS 24 HOURS AGO...WITH
TOTAL PRECIP WATER NEAR 1.05 INCHES. THE ENVIRONMENT WAS MORE STABLE
VERSUS 24 HOURS AGO...WITH LIFTED INDEX OF PLUS 2 AND NO CAPE.
29/12Z UPPER AIR PLOTS FEATURED A 592 DM HIGH PRESSURE CENTERED OVER
SE TEXAS...AND 584 DM LOW PRESSURE CENTERED JUST OFF THE SRN
CALIFORNIA COAST VICINITY. LIGHT GENERALLY SWLY FLOW PREVAILED OVER
SE AZ.
29/12Z NAM AND RUC HRRR WERE QUITE SIMILAR TO THE OFFICIAL FORECAST
IN DEPICTING QPF/S THIS AFTERNOON AND EARLY THIS EVENING ACROSS THE
WHITE MOUNTAINS...AND MOSTLY NEAR THE CHIRICAHUA MOUNTAINS AND
HUACHUCA MOUNTAINS IN COCHISE COUNTY. DRY CONDITIONS ARE FORECAST TO
OCCUR ELSEWHERE INTO THIS EVENING. EXPECT DRY CONDITIONS AREA WIDE
LATE TONIGHT. HIGH TEMPS THIS AFTERNOON WILL BE NEARLY IDENTICAL OR
ABOUT 2-4 DEGS F WARMER VERSUS SUNDAY DEPENDING UPON LOCATION.
THERE ARE NO UPDATES PLANNED AT THIS TIME. PLEASE REFER TO THE
PREVIOUS DISCUSSION SECTION BELOW FOR ADDITIONAL DETAIL.
&&
.PREV DISCUSSION /234 AM MST MON JUL 29 2013/...TUESDAY...UPPER HIGH
WILL CONTINUE TO SLOWLY MIGRATE NORTH INTO WEST CENTRAL NEW MEXICO.
FLOW ALOFT WILL BECOME MORE EASTERLY WITH MODELS SUGGESTING A WEAK
INVERTED TROF EXTENDING FROM NORTHERN CHIHUAHUA TO SOUTHERN SONORA
MEXICO. WILL SEE A SLIGHT INCREASE IN PRECIPITABLE WATER ACROSS THE
AREA...WITH THE BEST CHANCE FOR AFTERNOON/EVENING STORMS BEING SOUTH
OF SAN SIMON TO TUBAC LINE AND UP IN THE WHITES. HIGHS WILL BE AT OR
SLIGHTLY WARMER THAN WHAT IS FORECAST FOR TODAY.
WEDNESDAY...UPPER HIGH ACROSS CENTRAL NEW MEXICO WITH EASTERLY FLOW
ACROSS THE AREA. THE AREA WILL AGAIN SEE A SLIGHT INCREASE IN
PRECIPITABLE WATER. AREAL COVERAGE OF STORMS WILL ALSO INCREASE WITH
SLIGHT CHANCES AS FAR WEST AS CENTRAL PIMA COUNTY. THE HOTTEST HIGHS
IN THIS FORECAST CYCLE LIKELY WILL OCCUR TO CLOSE OUT JULY.
THURSDAY THROUGH SUNDAY...LOW TO MID GRADE MONSOON FORECAST AS MOIST
E-SE FLOW CONTINUES WITH UPPER HIGH OVER TEXAS. HIGHS WILL GRADUALLY
COOL DURING THE PERIOD.
&&
.AVIATION...VALID THRU 30/18Z. FEW-SCT080 SCT-BKN350. AFT 29/20Z
ISOLD TSRA THRU 30/04Z OVER THE WHITE MTNS...ALG NEW MEXICO BORDER
AND ACROSS SOUTHERN COCHISE COUNTY...WITH WIND GUSTS UP TO 40 KTS
NEAR TSRA. OTHERWISE...SURFACE WIND GENERALLY 10 KTS AND DIURNAL IN
DIRECTION. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...DRIER CONDITIONS WILL BE IN PLACE OVER THE REGION
THROUGH TUESDAY WITH LOWER HUMIDITIES AND A SMALL THREAT OF
THUNDERSTORMS LIMITED TO NEAR THE STATE BORDER WITH NEW MEXICO AND
ALONG THE INTERNATIONAL BORDER FROM NOGALES EAST. AS THE WEEK
PROGRESSES...MOISTURE VALUES ACROSS THE REGION WILL GRADUALLY
INCREASE WITH AN UPPER HIGH TO OUR EAST. THIS WILL LEAD TO AN
INCREASE IN THUNDERSTORMS DURING THE SECOND HALF OF THE WEEK AND
CONTINUING INTO THE UPCOMING WEEKEND. WINDS THROUGH THE PERIOD WILL
BE DIURNALLY DRIVEN AND GENERALLY BELOW 15 MPH OUTSIDE ANY
THUNDERSTORM ACTIVITY.
&&
.CLIMATE...RAINFALL THAT OCCURRED IN DOUGLAS ON SUNDAY RAISED THE
JULY TOTAL TO OVER 10" AND THEIR MONSOON TOTAL TO 10.23". THE
DOUGLAS MONSOON TOTAL CURRENTLY RANKS AS THE 11TH WETTEST MONSOON ON
RECORD. WITH 64 DAYS LEFT IN THE 2013 MONSOON...DOUGLAS HAS AN
OUTSIDE SHOT AT THREATENING THE ALL-TIME WETTEST MONSOON TOTAL OF
15.90" WHICH OCCURRED IN 1964.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
PREVIOUS DISCUSSION/CLIMATE...JG
AVIATION/FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION
NWS EUREKA CA
358 PM PDT TUE JUL 30 2013
.SYNOPSIS...LOW CLOUDS WILL CONTINUE TO INFLUENCE COASTAL LOCATIONS
OVER THE NEXT SEVERAL DAYS BUT EXPECT SOME AFTERNOON CLEARING.
EXPECT A COOLING TREND OVER THE INTERIOR WITH HIGHS ONLY IN THE 80S
BY MIDWEEK.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
LOOKING AT THE LATEST VISIBLE SATELLITE IMAGE, LITTLE IF ANY
CLEARING ALONG THE COAST TODAY WITH MINIMAL MIXING AND LIGHT S/SW
WINDS UNDER SOME SUBTLE UPPER RIDGING. CONDITIONS SHOULD IMPROVE
TOMORROW AND THROUGH THE END OF THE WEEK, AS THERE WILL STILL BE
NORTHERLY ONSHORE FLOW, BUT THE IMPROVED MIXING AND FLOW SHOULD
PROMOTE CLEARER SKIES SOUTH OF CAPE MENDO, AND ALONG THE NORTH COAST
EACH AFTERNOON.
AN UPPER LEVEL TROUGH WILL GRADUALLY PUSH TOWARD THE PACIFIC
NORTHWEST AND EVENTUALLY PUSH THROUGH BY THE MIDDLE TO LATER
PORTIONS OF THE WEEK. THIS WILL RESULT IN A COOLING TREND WEDNESDAY
AND THURSDAY, WITH HIGHS ONLY IN THE 80S ACROSS THE INTERIOR
VALLEYS. THE TROUGH WILL CARRY LIMITED MOISTURE WITH IT, AND
INSTABILITY INDICIES AND LAPSE RATES LOOK VERY MARGINAL FOR ANY
THUNDERSTORM ACTIVITY. WITH JET ENERGY MOVING THROUGH TONIGHT INTO
WEDNESDAY HOWEVER, THERE WILL BE A SMALL CHC OF DRY T-STORMS ALONG
THE BORDER OF DEL NORTE AND SISKIYOU COUNTY. SEE FIRE WX DISCUSSION
BELOW FOR MORE DETAIL. OF PERHAPS MORE IMPORTANCE, THE INCREASING
SOUTHERLY FLOW ALOFT AND INCREASED MIXING WILL HELP CLEAR SMOKE
ALOFT, AND SHOULD BEGIN TO IMPROVE CONDITIONS IN THOSE INLAND
VALLEYS WEDNESDAY MORNING IF NOT BY THURSDAY. CONDITIONS WILL STILL
REMAIN RATHER SMOKY IN THE UPPER KLAMATH, HOWEVER. AAD
&&
.LONG TERM (FRI NIGHT THRU TUE)...NO CHANGES MADE TO THE LONG TERM
FORECAST FROM THE MORNING PACKAGE. AFTERNOON MODEL RUNS CONTINUE TO
SHOW A WARMING TREND THROUGH THE WEEKEND AS THE UPPER TROUGH FILLS.
THIS UPPER TROUGH WILL CONTINUE TO CAUSE HEADACHES WITH THE
FORECAST. MODELS CONTINUE TO PROG SOME INSTABILITY OVER THE INTERIOR
MOUNTAINS FOR THE WEEKEND AND INTO EARLY NEXT WEEK. HAVE KEPT THE
SLIGHT CHANCE OF THUNDERSTORMS IN ON SUNDAY AND MONDAY AFTERNOON
OVER THE UPPER TRINITY. SUNDAY LOOKS TO HAVE THE BEST POTENTIAL FOR
THUNDERSTORMS WITH LI`S TO -2C...DECENT MID LEVEL LAPSE RATES...AND
MU CAPE UP TO 500 J/KG. MODELS ARE ALSO HINTING AT CONVECTION FOR
TUE. CONFIDENCE OF TSTMS FOR THE WEEKEND INTO EARLY NEXT WEEK IS
MODERATE, BUT THE CONFIDENCE IN TIMING IS LOW. HENCE SPREADING THE
SLIGHT CHANCE OVER A COUPLE OF DAYS. WILL BEGIN TO NARROW THE WINDOW
AS MODELS GAIN A BETTER GRASP ON HOW THE UPPER LOW WILL BEHAVE.
BFG/STP
&&
.FIRE WEATHER...
IN GENERAL, SIGNIFICANT FIRE WEATHER HAZARDS ARE NOT EXPECTED, BUT
THERE IS A SMALL CHANCE OF DRY LIGHTNING OVER EASTERN DEL NORTE
COUNTY OVERNIGHT, AND WANTED TO AT LEAST HIGHLIGHT SOME FIRE-RELATED
WEATHER HERE WITH RESPECT TO THE DANCE FIRE NEAR ORLEANS. GENERALLY
WX CONDITIONS WILL AID IN REDUCING FIRE BEHAVIOR OVERNIGHT AND
WEDNESDAY AM, AS WINDS WILL BECOME LIGHT AND DOWNSLOPE/DOWNVALLEY
AFTER MIDNIGHT AND RH RECOVERIES WILL EVEN BE BETTER THAN LAST NIGHT
WITH A DEEPER ONSHORE PUSH FROM THE APPROACHING TROUGH. WHILE
LACKING A DEEP LAYER OF MOISTURE, THERE IS SUBSTANTIAL UPPER LEVEL
MOISTURE AND SOME DIVERGENT/DIFFLUENT FLOW ALOFT BRIEFLY WED AM
UNDER THE LF QUAD OF A JET MAX. FCST SOUNDINGS ARE VERY DRY BELOW
500 MB WITH PWS UNDER .75 INCHES SO EXPECT VERY LITTLE RAIN WITH
ANYTHING THAT DOES DEVELOP. LAPSE RATES ARE RATHER POOR ALOFT,
HOWEVER, SO EXPECT MORE HIGH/MID CLOUD DEVELOPMENT THAN T-STORM
ACTIVITY. PLUS, ANYTHING THAT DOES DEVELOP WILL QUICKLY TRACK
NORTHEAST INTO SISKIYOU COUNTY. THINK ANY ACTIVITY WED/THU PM WILL
STAY EAST OF OUR COUNTIES. W/SW WINDS MAY BE SLIGHTLY GUSTIER WED PM
OVER EXPOSED TERRAIN AND ORIENTED VALLEYS, BUT TEMPS SHOULD BE A BIT
COOLER WITH HIGHER RH. THESE CONDITIONS SHOULD ALSO HELP CONTINUE TO
TAKE SMOKE OUT OF THE AREA AND INTO OREGON AND NE CALIFORNIA, EXCEPT
RIGHT NEAR THE UPPER KLAMATH NEAR THE FIRE AREA.
&&
.AVIATION...
LITTLE IF ANY CLEARING ALONG THE COAST TODAY WITH MINIMAL MIXING AND
LIGHT S/SW WINDS UNDER SOME SUBTLE UPPER RIDGING. WITH UPPER TROUGH
APPROACHING, SUSPECT FORECAST CIGS MAY NEED TO BE RAISED, AND COULD
BE ONE OF THOSE NIGHTS WHERE CIGS LEVEL OFF OR ACTUALLY STAY UP
ABOVE 1000 FT. EXPECT LITTLE IF ANY VSBY REDUCTION OUTSIDE OF
LOCALLY TRAPPED SMOKE IN SOME INTERIOR VALLEYS, ESPECIALLY THE
KLAMATH. OPTIMISTIC FOR CLEARING WITH DEEPER MARINE LAYER AND BETTER
MIXING TOMORROW AFTERNOON, BUT WITH STILL MOIST ONSHORE FLOW, IT IS
POSSIBLE THE CLEARING IS SHORT-LIVED. AT LEAST CIGS SHOULD BE ABOVE
1000 OR EVEN CLOSER TO 2000 FT. AAD
&&
.MARINE...LIFTED CLOUD DECKS, LOW SEAS, AND LIGHT TO MODERATE WINDS
ARE THE STORY FOR THE COASTAL WATERS TODAY INTO TOMORROW. BUOYS THIS
AFTERNOON ARE RUNNING ANYWHERE FROM 3 FEET IN THE NORTH TO AROUND 5
TO 6 FEET DOWN BY POINT ARENA. THIS IS EXPECTED TO REMAIN IN PLACE
THROUGH WEDNESDAY. WINDS ARE STILL FORECAST TO BE IN THE 15 TO 20 KT
RANGE DOWNWIND OF CAPE MENDOCINO, BUT SHOULD REMAIN WELL OFF THE
MENDOCINO COAST. HOWEVER, THIS WILL GENERATE SOME SHORT PERIOD STEEP
SEAS FOR AREAS SUCH AS POINT ARENA DESPITE LIMITED LOCAL WINDS. AN
8AM WINDSAT RADIOMETER PASS MATCHES WELL WITH THE HRRR MODEL SHOWING
15 TO 20 KT WINDS DOWNWIND. SO FEEL CONFIDENT WITH THIS FORECAST.
WINDS ARE SLATED TO INCREASE SLIGHTLY AGAIN LATE IN THE WEEK AS THE
SURFACE THERMAL TROUGH REDEVELOPS ACROSS INTERIOR CALIFORNIA, CAUSING
A TIGHTENING OF THE PRESSURE GRADIENT. AS IT STAND RIGHT NOW, WINDS
AND SEAS WILL PEAK FRI AND SAT THEN COME DOWN AGAIN ON SUN. MORE TO
COME. BFG
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS TAUNTON MA
710 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT MOVES ACROSS THE REGION TODAY...POSSIBLY TRIGGERING
AN ISOLATED SHOWER ESPECIALLY ACROSS EASTERN MASSACHUSETTS AND
RHODE ISLAND. HIGH PRESSURE BUILDS INTO THE NORTHEAST TONIGHT
THROUGH WED...DELIVERING DRY WEATHER TO THE AREA ALONG WITH
COMFORTABLE TEMPERATURES AND HUMIDITY. ANOTHER FRONTAL SYSTEM
APPROACHES NEW ENGLAND THU AND FRI WITH SHOWERS LIKELY. COOLER AND
MAINLY DRY WEATHER ARE THE LATEST TRENDS FOR NEXT WEEKEND
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE..
LOW CLOUDS AND FOG CONTINUE TO STREAM ACROSS THE AREA. EARLY
CONVECTION UPSTREAM ACROSS EASTERN PA/NJ AND THE LOWER HUDSON
VALLEY HAS COMPLETELY ERODED. UNFORTUNATELY NONE OF THE GUID
SIMULATED THIS VERY WELL...WITH MODELS PROJECTING CONVECTION
CONTINUING THIS MORNING. THIS INCLUDES THE HRRR. PERHAPS
CONVECTION WELL SOUTH OF NEW ENGLAND OVER THE OCEAN ROBBED THIS
AREA OF MOISTURE AND INSTABILITY. NONETHELESS COLD FRONT ENTERING
THE NYC AREA AND HUDSON VALLEY OF NY. DEW PTS STILL IN THE MU 60S
TO NEAR 70 ACROSS NEW ENGLAND AHEAD OF THE FRONT. MODELS SUGGEST
UP TO 1500 J/KG OF CAPE BY 18Z. WINDOW OF OPPORTUNITY FOR
CONVECTION WILL BE SMALL...AS DEEP LAYER DRY AIR ALOFT IS RACING
EASTWARD AND WILL LIMIT DEEP CONVECTION ACROSS NEW ENGLAND. THUS
BEST CHANCE FOR SHOWERS/TSTMS WILL BE 15Z-18Z AND ACROSS EASTERN
MA AND RI WHERE SEA BREEZE BOUNDARIES WILL ENHANCE LOW LEVEL
CONVERGENCE AND HELP MOISTEN THE COLUMN. NEVERTHELESS AREAL
COVERAGE SHOULD BE ISOLATED AND DIMINISH MID TO LATE AFTERNOON
FROM WEST TO EAST. GIVEN THESE LIMITING FACTORS WE LOWERED POPS
FROM CHANCE TO SLIGHT CHANCE. EARLIER DISCUSSION BELOW.
---------------------------------------------------------------
AREAS OF FOG HAVE DEVELOPED IN PORTIONS OF SOUTHERN NEW ENGLAND...IN
PARTICULAR EAST COASTAL MA. THE FOG WILL REDUCE VISIBILITY TO 1/2
MILE AT TIMES THROUGH 7 AM. THE FOG IS EXPECTED TO LIFT AND
DISSIPATE BY MID MORNING.
A COLD FRONT EXTENDING NORTH TO SOUTH THROUGH EASTERN NY AND NJ
IS EXPECTED TO PUSH INTO SOUTHERN NEW ENGLAND EARLY THIS MORNING.
MODELS INDICATE THAT THE SURFACE FRONT MAY TAKE THE ENTIRE DAY TO
PUSH THROUGH OUR AREA...POSSIBLY INTO THE EVENING ACROSS FAR
EASTERN ZONES. HOWEVER...PRONOUNCED MID LEVEL DRYING MOVES IN FROM
W TO E DURING THE LATE MORNING AND EARLY AFTERNOON ACROSS OUR
AREA. NAM AND RAP INDICATE PWATS FALL TO AROUND AN INCH BY 18Z IN
WESTERN HALF OF THE FORECAST AREA...GFS PUSHES IN DRIER AIR
QUICKER. WITH APPROACH OF FROPA AND SCATTERED LINGERING SHOWERS
ALONG AND AHEAD OF THE FRONT IT IS PRUDENT TO START OFF THE DAY
WITH CHANCE POPS. THEN WITH MODELS INTRODUCING SIGNIFICANT MID
LEVEL DRYING WILL GRADUALLY DROP OFF POPS FROM WEST TO EAST...WITH
ONLY A SLIGHT CHANCE POP E COASTAL MA AND VICINITY DURING EARLY-
MID AFTERNOON WITH THE ADDED POSSIBILITY THERE THAT SEA BREEZE
DEVELOPMENT COULD HELP TRIGGER SOME SHOWERS.
CONSIDERABLE CLOUDINESS TO START OFF THE DAY WITH A MIX OF STRATUS
AND CONVECTIVE DEBRIS CLOUDS...THEN GRADUAL DECREASE IN CLOUDS
EXPECTED FROM WEST TO EAST.
USING A BLEND OF MAV/MET GUIDANCE WITH MAX TEMPS IN THE LOW TO MID
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
MONDAY NIGHT...COLD FRONT MOVES OFFSHORE...WHILE HIGH PRESSURE
BUILDS OVER THE OHIO VALLEY. MOSTLY CLEAR SKIES WITH MIN TEMPS OF
55 TO 65 DEGREES...COOLEST OVER THE FAR INTERIOR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGHLIGHTS...
* TEMPS AT OR SLIGHTLY COOLER THAN NORMAL
* SHOWERS LIKELY LATE THU INTO FRI
* NEXT WEEKEND IS TRENDING COOLER BUT MAINLY DRY
SYNOPTIC OVERVIEW...
GOOD MODEL AGREEMENT AMONG THE ECENS AND GEFS ENSEMBLES ON THE
NORTHERN STREAM JET REMAINING AMPLIFIED AND SUPPRESSED ACROSS THE
GREAT LAKES AND NEW ENGLAND THIS PERIOD. THIS WILL RESULT IN A STORM
TRACK ACROSS OR SOUTH OF THE REGION...YIELDING AN ACTIVE WEATHER
PATTERN FOR THE AREA BUT CONFINING ANY SEVERE WEATHER THREAT AND
EXCESSIVE HEAT WELL SOUTH AND SOUTHWEST OF NEW ENGLAND. THIS IS
SUPPORTED BY LATEST TELECONNECTIONS WITH NAO AND AO REMAINING WEAKLY
NEGATIVE DURING THIS FORECAST PERIOD.
SENSIBLE WEATHER...
TUE...
SIGNIFICANT AIRMASS CHANGE BEHIND MON NIGHT/S COLD FRONT WITH PWATS
DIPPING BELOW 1 INCH AND DEW PTS FALLING INTO THE U40S TO L50S!
REFRESHING WNW WIND TO ACCOMPANY THE COOLER/LESS HUMID AIRMASS TUE.
PGRAD LOOKS ROBUST ENOUGH TO PRECLUDE ANY SEABREEZES.
WED...
RIDGE OF HIGH PRES CREST OVER THE REGION AROUND 12Z...THEN SLIPPING
OFFSHORE. THIS WILL RESULT IN A COOL START BUT TEMPS WILL REBOUND
QUICKLY AS STRONG JULY SUNSHINE COMBINES WITH WEAK WARM AIR
ADVECTION AS RETURN FLOW GETS UNDERWAY. DEW PTS WILL INCH UPWARD
ESPECIALLY ALONG THE SOUTH COAST...BUT STILL ANOTHER GEM OF A DAY
WITH PLENTY OF SUNSHINE AND COMFORTABLE TEMPS AND HUMIDITY.
THU/FRI...
NEXT SHORT WAVE AND ATTENDING FRONTAL BOUNDARY APPROACHES THE REGION
LATE THU INTO FRI. FAIRLY AMPLIFIED TROUGH WITH NEGATIVE TILT. ALL
MODELS ESPECIALLY THE ECMWF SUGGEST THIS STRONG FORCING FOR ASCENT
WILL INDUCE A FRONTAL WAVE AND TRACK ALONG OR SOUTH OF NEW ENGLAND.
MORE LIKE A COOL SEASON EVENT THAN A TYPICAL SUMMER FRONTAL SYSTEM.
MODELS ALSO ADVERTISING SOME ELEVATED INSTABILITY ALONG WITH GOOD
MOISTURE ADVECTION AS PWATS CLIMB ABOVE 1.5 INCHES. ALL OF THESE
ATTRIBUTES SUGGEST A RISK FOR ENHANCED QPF. AS FOR TIMING...
SURPRISINGLY AT THIS TIME RANGE ENSEMBLES AND DETERMINISTIC GUID IN
GOOD AGREEMENT WITH HIGHEST PROBABILITY OF RAIN/SHOWERS FROM LATE
THU INTO EARLY FRI. IN FACT 00Z GEFS ENSEMBLES OFFERING LIKELY POPS
DURING THIS TIME PERIOD. TEMPS HERE WILL LIKELY BE ON THE COOL SIDE
GIVEN CLOUD COVER/RAIN AND ESPECIALLY IF SURFACE WAVE TRACKS SOUTH
OF THE REGION.
SAT/SUN...
ECENS AND GEFS ENSEMBLES BOTH HAVE POLAR VORTEX MOVING EQUATORWARD
INTO SOUTH-CENTRAL QUEBEC WITH HEIGHTS OVER NEW ENGLAND DIPPING TO
MINUS 2 STANDARD DEVIATIONS FROM CLIMO! THIS WILL SUPPORT COOLER
TEMPS. DETERMINISTIC RUNS OF THE GFS AND ECMWF ARE EVEN MORE ROBUST.
AS FOR PRECIP...PATTERN SUGGEST DRY WEATHER WITH STORM TRACK
SUPPRESSED SOUTH OF NEW ENGLAND. HOWEVER GIVEN COLD AIR ALOFT CAN/T
RULE OUT ISOLATED DIURNAL SHOWER/TSTM ESPECIALLY HIGHER TERRAIN.
FOR NEXT WEEK ALL MODEL GUID INDICATING POTENTIAL RECORD COOL TEMPS
FOR NEW ENGLAND AS POLAR VORTEX MAY CONTINUE TO DIG SOUTHWARD
THROUGH QUEBEC.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERALL...MODERATE CONFIDENCE BUT LOW CONFIDENCE ON CAPE/ISLANDS.
TODAY...ACROSS EAST COASTAL MA IFR/LIFR CIGS/VSBYS TO START IN
STRATUS AND FOG...IMPROVING TO MVFR AFTER 12-13Z...THEN IMPROVING TO
VFR BY 18Z. ON CAPE/AND ISLANDS A PERIOD OF IFR CONDITIONS IS
EXPECTED TO FORM PRIOR TO 12Z AND LAST FOR A FEW HOURS...THEN CIGS
IMPROVE TO VFR BY 18Z. OVER THE INTERIOR...MVFR/LOCALIZED IFR
CIGS/VSBYS IN FOG IMPROVE TO VFR AFTER 12Z. ISOLD-SCT SHOWERS DURING
THE MORNING...AND EARLY AFTERNOON EAST COASTAL MA THRU 19Z.
TONIGHT...HIGH CONFIDENCE VFR.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. IFR/LIFR CIGS/VSBYS
PERSIST THRU 13Z...THEN CIGS/VSBYS GRADUALLY IMPROVE AFTER 13Z. CIGS
IMPROVE TO VFR BY 18Z.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CIGS/VSBYS SHOULD
DEVELOP FOR A PERIOD OF TIME EARLY THIS MORNING...BECOMING VFR BY
13Z. SCATTERED SHOWERS POSSIBLE THRU 15Z.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...HIGH CONFIDENCE FOR VFR AND DRY WEATHER. SEABREEZES
LIKELY WED.
THU AND FRI...A PERIOD OF MVFR/IFR POSSIBLE ALONG WITH SHOWERS
LIKELY. HIGH CONFIDENCE ON SHOWERS BUT LOWER CONFIDENCE ON EXACT CIG
AND VSBY CATEGORIES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE.
TODAY...COLD FRONT APPROACHES THE WATERS TODAY BUT WINDS ARE
EXPECTED TO BE 15KT OR LESS. SEAS ON THE SOUTHERN OUTER COASTAL
WATERS EXPECTED TO PRIMARILY BE 2 TO 4 FT BUT THERE IS A CHANCE FOR
5 FT SEAS FOR A SHORT TIMEFRAME.
TONIGHT...WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA THRESHOLDS.
COLD FRONT CROSSES THE WATERS WITH WINDS BECOMING NW AROUND 10 KT
AFTER MIDNIGHT.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...FINE BOATING WEATHER WITH HIGH PRES IN CONTROL OF THE
NORTHEAST. TRANQUIL SEAS GIVEN LIGHT WINDS AND SMALL SWELLS. GOOD
VSBY AS WELL.
THU AND FRI...STRONG FRONTAL SYSTEM AND SURFACE WAVE LIKELY WITH LOW
TRACKING ALONG OR NEAR SOUTHERN NEW ENGLAND COAST. SHOWERS AND FOG
WILL YIELD POOR VSBY. LOW CONFIDENCE ON WIND FORECAST GIVEN
UNCERTAINTY ON EXACT TRACK AND INTENSITY OF LOW.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/NMB
NEAR TERM...NOCERA/NMB
SHORT TERM...NMB
LONG TERM...NOCERA
AVIATION...NOCERA/NMB
MARINE...NOCERA/NMB
AREA FORECAST DISCUSSION
NWS TAUNTON MA
356 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT MOVES ACROSS THE REGION TODAY...POSSIBLY TRIGGERING
AN ISOLATED SHOWER ESPECIALLY ACROSS EASTERN MASSACHUSETTS AND
RHODE ISLAND. HIGH PRESSURE BUILDS INTO THE NORTHEAST TONIGHT
THROUGH WED...DELIVERING DRY WEATHER TO THE AREA ALONG WITH
COMFORTABLE TEMPERATURES AND HUMIDITY. ANOTHER FRONTAL SYSTEM
APPROACHES NEW ENGLAND THU AND FRI WITH SHOWERS LIKELY. COOLER AND
MAINLY DRY WEATHER ARE THE LATEST TRENDS FOR NEXT WEEKEND
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
4 AM UPDATE..
AREAS OF FOG HAVE DEVELOPED IN PORTIONS OF SOUTHERN NEW ENGLAND...IN
PARTICULAR EAST COASTAL MA. THE FOG WILL REDUCE VISIBILITY TO 1/2
MILE AT TIMES THROUGH 7 AM. THE FOG IS EXPECTED TO LIFT AND
DISSIPATE BY MID MORNING.
A COLD FRONT EXTENDING NORTH TO SOUTH THROUGH EASTERN NY AND NJ
IS EXPECTED TO PUSH INTO SOUTHERN NEW ENGLAND EARLY THIS MORNING.
MODELS INDICATE THAT THE SURFACE FRONT MAY TAKE THE ENTIRE DAY TO
PUSH THROUGH OUR AREA...POSSIBLY INTO THE EVENING ACROSS FAR
EASTERN ZONES. HOWEVER...PRONOUNCED MID LEVEL DRYING MOVES IN FROM
W TO E DURING THE LATE MORNING AND EARLY AFTERNOON ACROSS OUR
AREA. NAM AND RAP INDICATE PWATS FALL TO AROUND AN INCH BY 18Z IN
WESTERN HALF OF THE FORECAST AREA...GFS PUSHES IN DRIER AIR
QUICKER. WITH APPROACH OF FROPA AND SCATTERED LINGERING SHOWERS
ALONG AND AHEAD OF THE FRONT IT IS PRUDENT TO START OFF THE DAY
WITH CHANCE POPS. THEN WITH MODELS INTRODUCING SIGNIFICANT MID
LEVEL DRYING WILL GRADUALLY DROP OFF POPS FROM WEST TO EAST...WITH
ONLY A SLIGHT CHANCE POP E COASTAL MA AND VICINITY DURING EARLY-
MID AFTERNOON WITH THE ADDED POSSIBILITY THERE THAT SEA BREEZE
DEVELOPMENT COULD HELP TRIGGER SOME SHOWERS.
CONSIDERABLE CLOUDINESS TO START OFF THE DAY WITH A MIX OF STRATUS
AND CONVECTIVE DEBRIS CLOUDS...THEN GRADUAL DECREASE IN CLOUDS
EXPECTED FROM WEST TO EAST.
USING A BLEND OF MAV/MET GUIDANCE WITH MAX TEMPS IN THE LOW TO MID
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
MONDAY NIGHT...COLD FRONT MOVES OFFSHORE...WHILE HIGH PRESSURE
BUILDS OVER THE OHIO VALLEY. MOSTLY CLEAR SKIES WITH MIN TEMPS OF
55 TO 65 DEGREES...COOLEST OVER THE FAR INTERIOR.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGHLIGHTS...
* TEMPS AT OR SLIGHTLY COOLER THAN NORMAL
* SHOWERS LIKELY LATE THU INTO FRI
* NEXT WEEKEND IS TRENDING COOLER BUT MAINLY DRY
SYNOPTIC OVERVIEW...
GOOD MODEL AGREEMENT AMONG THE ECENS AND GEFS ENSEMBLES ON THE
NORTHERN STREAM JET REMAINING AMPLIFIED AND SUPPRESSED ACROSS THE
GREAT LAKES AND NEW ENGLAND THIS PERIOD. THIS WILL RESULT IN A STORM
TRACK ACROSS OR SOUTH OF THE REGION...YIELDING AN ACTIVE WEATHER
PATTERN FOR THE AREA BUT CONFINING ANY SEVERE WEATHER THREAT AND
EXCESSIVE HEAT WELL SOUTH AND SOUTHWEST OF NEW ENGLAND. THIS IS
SUPPORTED BY LATEST TELECONNECTIONS WITH NAO AND AO REMAINING WEAKLY
NEGATIVE DURING THIS FORECAST PERIOD.
SENSIBLE WEATHER...
TUE...
SIGNIFICANT AIRMASS CHANGE BEHIND MON NIGHT/S COLD FRONT WITH PWATS
DIPPING BELOW 1 INCH AND DEW PTS FALLING INTO THE U40S TO L50S!
REFRESHING WNW WIND TO ACCOMPANY THE COOLER/LESS HUMID AIRMASS TUE.
PGRAD LOOKS ROBUST ENOUGH TO PRECLUDE ANY SEABREEZES.
WED...
RIDGE OF HIGH PRES CREST OVER THE REGION AROUND 12Z...THEN SLIPPING
OFFSHORE. THIS WILL RESULT IN A COOL START BUT TEMPS WILL REBOUND
QUICKLY AS STRONG JULY SUNSHINE COMBINES WITH WEAK WARM AIR
ADVECTION AS RETURN FLOW GETS UNDERWAY. DEW PTS WILL INCH UPWARD
ESPECIALLY ALONG THE SOUTH COAST...BUT STILL ANOTHER GEM OF A DAY
WITH PLENTY OF SUNSHINE AND COMFORTABLE TEMPS AND HUMIDITY.
THU/FRI...
NEXT SHORT WAVE AND ATTENDING FRONTAL BOUNDARY APPROACHES THE REGION
LATE THU INTO FRI. FAIRLY AMPLIFIED TROUGH WITH NEGATIVE TILT. ALL
MODELS ESPECIALLY THE ECMWF SUGGEST THIS STRONG FORCING FOR ASCENT
WILL INDUCE A FRONTAL WAVE AND TRACK ALONG OR SOUTH OF NEW ENGLAND.
MORE LIKE A COOL SEASON EVENT THAN A TYPICAL SUMMER FRONTAL SYSTEM.
MODELS ALSO ADVERTISING SOME ELEVATED INSTABILITY ALONG WITH GOOD
MOISTURE ADVECTION AS PWATS CLIMB ABOVE 1.5 INCHES. ALL OF THESE
ATTRIBUTES SUGGEST A RISK FOR ENHANCED QPF. AS FOR TIMING...
SURPRISINGLY AT THIS TIME RANGE ENSEMBLES AND DETERMINISTIC GUID IN
GOOD AGREEMENT WITH HIGHEST PROBABILITY OF RAIN/SHOWERS FROM LATE
THU INTO EARLY FRI. IN FACT 00Z GEFS ENSEMBLES OFFERING LIKELY POPS
DURING THIS TIME PERIOD. TEMPS HERE WILL LIKELY BE ON THE COOL SIDE
GIVEN CLOUD COVER/RAIN AND ESPECIALLY IF SURFACE WAVE TRACKS SOUTH
OF THE REGION.
SAT/SUN...
ECENS AND GEFS ENSEMBLES BOTH HAVE POLAR VORTEX MOVING EQUATORWARD
INTO SOUTH-CENTRAL QUEBEC WITH HEIGHTS OVER NEW ENGLAND DIPPING TO
MINUS 2 STANDARD DEVIATIONS FROM CLIMO! THIS WILL SUPPORT COOLER
TEMPS. DETERMINISTIC RUNS OF THE GFS AND ECMWF ARE EVEN MORE ROBUST.
AS FOR PRECIP...PATTERN SUGGEST DRY WEATHER WITH STORM TRACK
SUPPRESSED SOUTH OF NEW ENGLAND. HOWEVER GIVEN COLD AIR ALOFT CAN/T
RULE OUT ISOLATED DIURNAL SHOWER/TSTM ESPECIALLY HIGHER TERRAIN.
FOR NEXT WEEK ALL MODEL GUID INDICATING POTENTIAL RECORD COOL TEMPS
FOR NEW ENGLAND AS POLAR VORTEX MAY CONTINUE TO DIG SOUTHWARD
THROUGH QUEBEC.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERALL...MODERATE CONFIDENCE BUT LOW CONFIDENCE ON CAPE/ISLANDS.
TODAY...ACROSS EAST COASTAL MA IFR/LIFR CIGS/VSBYS TO START IN
STRATUS AND FOG...IMPROVING TO MVFR AFTER 12-13Z...THEN IMPROVING TO
VFR BY 18Z. ON CAPE/AND ISLANDS A PERIOD OF IFR CONDITIONS IS
EXPECTED TO FORM PRIOR TO 12Z AND LAST FOR A FEW HOURS...THEN CIGS
IMPROVE TO VFR BY 18Z. OVER THE INTERIOR...MVFR/LOCALIZED IFR
CIGS/VSBYS IN FOG IMPROVE TO VFR AFTER 12Z. ISOLD-SCT SHOWERS DURING
THE MORNING...AND EARLY AFTERNOON EAST COASTAL MA THRU 19Z.
TONIGHT...HIGH CONFIDENCE VFR.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. IFR/LIFR CIGS/VSBYS
PERSIST THRU 13Z...THEN CIGS/VSBYS GRADUALLY IMPROVE AFTER 13Z. CIGS
IMPROVE TO VFR BY 18Z.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR CIGS/VSBYS SHOULD
DEVELOP FOR A PERIOD OF TIME EARLY THIS MORNING...BECOMING VFR BY
13Z. SCATTERED SHOWERS POSSIBLE THRU 15Z.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...HIGH CONFIDENCE FOR VFR AND DRY WEATHER. SEABREEZES
LIKELY WED.
THU AND FRI...A PERIOD OF MVFR/IFR POSSIBLE ALONG WITH SHOWERS
LIKELY. HIGH CONFIDENCE ON SHOWERS BUT LOWER CONFIDENCE ON EXACT CIG
AND VSBY CATEGORIES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE.
TODAY...COLD FRONT APPROACHES THE WATERS TODAY BUT WINDS ARE
EXPECTED TO BE 15KT OR LESS. SEAS ON THE SOUTHERN OUTER COASTAL
WATERS EXPECTED TO PRIMARILY BE 2 TO 4 FT BUT THERE IS A CHANCE FOR
5 FT SEAS FOR A SHORT TIMEFRAME.
TONIGHT...WINDS AND SEAS ARE EXPECTED TO BE BELOW SCA THRESHOLDS.
COLD FRONT CROSSES THE WATERS WITH WINDS BECOMING NW AROUND 10 KT
AFTER MIDNIGHT.
OUTLOOK...TUESDAY THROUGH FRIDAY...
TUE AND WED...FINE BOATING WEATHER WITH HIGH PRES IN CONTROL OF THE
NORTHEAST. TRANQUIL SEAS GIVEN LIGHT WINDS AND SMALL SWELLS. GOOD
VSBY AS WELL.
THU AND FRI...STRONG FRONTAL SYSTEM AND SURFACE WAVE LIKELY WITH LOW
TRACKING ALONG OR NEAR SOUTHERN NEW ENGLAND COAST. SHOWERS AND FOG
WILL YIELD POOR VSBY. LOW CONFIDENCE ON WIND FORECAST GIVEN
UNCERTAINTY ON EXACT TRACK AND INTENSITY OF LOW.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/NMB
NEAR TERM...NMB
SHORT TERM...NMB
LONG TERM...NOCERA
AVIATION...NOCERA/NMB
MARINE...NOCERA/NMB
AREA FORECAST DISCUSSION
NWS MIAMI FL
910 AM EDT MON JUL 29 2013
.UPDATE...
LIGHT SE WIND FLOW HAS BECOME RE-ESTABLISHED OVER THE AREA WITH
COASTAL SHOWERS/TSTMS ATLANTIC AND EAST COAST THIS MORNING.
CURRENT FORECAST OF AFTERNOON CONVECTION SHIFTING TO INTERIOR AND
WESTERN SECTIONS OF SOUTH FLORIDA LOOKS ON TRACK AND IS CONSISTENT
WITH HIGH-RESOLUTION MODELS SUCH AS HRRR AND WRF. SOME MINOR
ADJUSTMENTS MAY BE NEEDED IN THE LATE MORNING FORECAST UPDATE,
PRIMARILY TO INCREASE POPS SLIGHTLY FROM THE 30/40 RANGE CURRENTLY
DEPICTED FOR THE INTERIOR AND WEST THIS AFTERNOON. INSTABILITY
PARAMETERS NOT TOO IMPRESSIVE BASED ON 12Z SOUNDING DATA, SO
STORMS THIS AFTERNOON SHOULD BE MAINLY GARDEN VARIETY.
MOLLEDA
&&
.PREV DISCUSSION... /ISSUED 733 AM EDT MON JUL 29 2013/
AVIATION...
A FEW SHRA/TSRA OVER THE ATLANTIC THIS MORNING BUT ONLY NEAR THE
KPBI TERMINAL AT THIS TIME. SOUTHEAST FLOW WILL TEND TO DIMINISH
THIS ACTIVITY DURING THE FIRST COUPLE OF HOURS AND THEN REDEVELOP
INLAND WITH MOVEMENT TOWARDS THE INTERIOR AND SOUTHWEST COAST. VFR
CONDITIONS ARE EXPECTED BUT THERE COULD BE SOME BRIEF MVFR/IFR AT
KAPF THIS AFTERNOON. SEA BREEZES WILL DEVELOP ALONG BOTH COASTS BY
LATE THIS MORNING OR EARLY AFTERNOON.
JE/KOB
PREV DISCUSSION... /ISSUED 426 AM EDT MON JUL 29 2013/
DISCUSSION...
ISOLATED SHOWERS CONTINUE TO DEVELOP ACROSS THE ATLANTIC WATERS THIS
MORNING AS THE MARINE BOUNDARY LAYER MOISTENS. A FEW OF THESE
SHOWERS ARE ALSO BEGINNING TO MAKE THEIR WAY INLAND ACROSS THE EAST
COAST METRO AREAS. THESE SHOWERS SHOULD CONTINUE TO BE LIGHT AND
SPARSE IN NATURE THROUGH THE MORNING.
THE FIRST HALF OF THE WEEK WILL BE MARKED BY THE RETURN OF EASTERLY
FLOW ACROSS THE AREA. DEEP H5 TROUGH ACROSS THE GREAT LAKES WILL
CONTINUE TO RETREAT TO NORTHEAST INTO QUEBEC THROUGH THE DAY. THIS
WILL ALLOW THE BERMUDA HIGH TO BECOME MORE FIRMLY ENTRENCHED ACROSS
THE WESTERN ATLANTIC RESULTING IN PREVAILING EASTERLY FLOW ACROSS
SOUTH FLORIDA. AS A RESULT...THE MAJORITY OF THE AFTERNOON
CONVECTION IS EXPECTED TO BE CONFINED ACROSS THE INTERIOR AND GULF
COASTAL AREAS AS EASTERLY FLOW INTERACTS WITH AN EXPECTED GULF
BREEZE. MODEL SOUNDINGS AGAIN DEPICT STEERING FLOW TO BE VERY WEAK
WHICH WILL RESULT IN SLOW MOVING STORMS AND HEIGHTEN THE RISK OF
URBAN FLOODING. THIS PATTERN IS EXPECTED TO PERSIST THROUGH MIDWEEK
WITH CHANCES FOR AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS
EACH DAY.
BY THURSDAY THE REMNANTS OF DORIAN ARE EXPECTED TO BE APPROACHING
THE BAHAMA ISLANDS. THERE IS STILL UNCERTAINTY AS TO WHETHER DORIAN
WILL REGAIN STRENGTH INTO A TROPICAL SYSTEM. CURRENTLY THE NATIONAL
HURRICANE CENTER GIVES A 50% CHANCE RE-INTENSIFICATION INTO A
TROPICAL SYSTEM. HOWEVER...THERE CONTINUES TO BE NO APPARENT SURFACE
CIRCULATION AT THIS TIME. ALSO...BOTH THE GFS AND THE ECMWF DEPICT A
GRADUAL WEAKENING OF THE WAVE AS IT HEADS TOWARD SOUTH FLORIDA. EVEN
SO...IT COULD STILL PRODUCE HEAVY RAINS ACROSS SOUTH FLORIDA
THURSDAY THROUGH FRIDAY AS IT GETS CLOSER. RAISED POPS TO LIKELY
ACROSS THE INTERIOR AND GULF COASTAL AREAS FOR THURSDAY AFTERNOON AND
EVENING. MODELS ALSO DEPICT A HIGHLY AMPLIFIED H5 TROUGH DIGGING
SOUTH INTO THE OHIO VALLEY AND INTO THE DEEP SOUTH BY THURSDAY WHICH
SHOULD ALLOW THE REMNANTS OF DORIAN TO MAKE A MOVE TO THE NORTH AND
GET PICKED UP BY THE TROUGH.
SOUTHEAST SURFACE FLOW SHOULD CONTINUE INTO THE WEEKEND AS MID LEVEL
RIDGING BUILDS BACK ACROSS SOUTH FLORIDA. CHANCES FOR SEA BREEZE
INDUCED SHOWERS AND THUNDERSTORMS WILL ALSO PREVAIL.
AVIATION...
VFR WILL PREVAIL WITH LIGHT WINDS GENERALLY 5 KT OR LESS
OVERNIGHT. THE WIND SHIFT TO THE SE FOR THE ATLANTIC WATERS WILL
CONTINUE ON MONDAY AND INCREASE TO 10 KT IN THE AFTERNOON. FOR
KAPF, WINDS WILL BECOME SW ON MONDAY AFTERNOON WITH SPEEDS NEAR 10
KT. AFTERNOON TSTORMS ARE EXPECTED TO BE FOCUSED INTERIOR AND
WEST...ONLY HAVE VCSH FOR THE EAST COAST TERMINALS AND VCTS FOR
NAPLES.
MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE THROUGH THE MIDDLE OF THE
WEEK WITH A MODERATE EAST TO SOUTHEAST WIND FLOW AND SEAS LESS
THAN 4 FEET. THERE COULD BE A SLIGHT INCREASE IN WIND BY THE
LATTER HALF OF THE WEEK AS A TROPICAL WAVE APPROACHES THE LOCAL
WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 78 88 79 / 20 20 30 20
FORT LAUDERDALE 89 80 89 81 / 20 20 30 20
MIAMI 90 79 89 80 / 20 20 30 20
NAPLES 92 76 92 76 / 30 20 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
PUBLIC/MARINE...59/MOLLEDA
AVIATION/RADAR/FIRE...30/KOB
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
407 AM EDT Mon Jul 29 2013
.NEAR TERM [Through Tonight]...
The anomalously deep eastern U.S. long wave trough is beginning to
lose amplitude across the Southeastern U.S. as the parent low drifts
northeast into Canada. There are no obvious upstream short waves
that will impact the area today. In fact, we will see some influence
today from a weak upper high over LA. At the surface, a very weak
low is still analyzed near the MS/AL coast with a trough extending
east from it into our coastal waters and then northeast across the
FL Big Bend and South Central GA. Area radars are showing isolated
showers developing east of the low and north of the trough over the
FL Panhandle. A cold front is analyzed across central portions of AL
and MS. Showers and thunderstorms are expected to be less numerous
today across our northwestern zones and somewhat drier air filters
in to the north and we see a lack of upper level support. To the
east, the presence of the surface trough and onshore flow ahead of
the weak low should result in somewhat higher PoPs of about 40
percent in the TLH-VLD corridor. Afternoon max temperatures will be
within a degree or so of normal, mainly in the lower 90s. Coastal
areas will be held to the upper 80s due to the sea breeze.
&&
.SHORT TERM [Tuesday Through Wednesday Night]...
Deep layer ridging will be present during the start of the short
term period. This will usher in drier air, giving way to slightly
above average temperatures and reduced PoPs. On Tuesday
the highest PoPs will be confined to our far eastern CWA
where some residual moisture ahead of a weak surface trough will
be present. During the day on Wednesday an upper level shortwave
will move through our CWA, increasing mid-level moisture feed. Model
guidance is indicating a weak surface reflection associated with
the shortwave, which coupled with enhanced mid-level moisture will
enhance PoPs to levels at or above climatology normals.
&&
.LONG TERM [Thursday through Sunday]...
As was expected, the upper level ridge will not be around the CWA
for too long as it initially retrogrades westward into the desert
Southwest, reestablishing the all too familiar trof across the
region. This is expected to result in an above climo period of
PoPs (40-60% conservatively) at the moment for Thursday and near
climo temps. This ridge may head back eastward for the end of the
week and weekend, resulting in another seemingly rare warm up and
decrease in PoPs.
&&
.AVIATION...
[Through 06 UTC Tuesday] Hi res guidance including the HRRR indicate
that there is a change for low cigs, most likely IFR at DHN and MVFR
at ABY and we have only included this at those two terminals and
removed from VLD. Showers are expected to get an early start at ECP
and TLH. we maintained the inherited probabilities for TS at these
two terminals and VLD. Convective coverage is too low to include any
mention of TS at DHN and ABY for this afternoon.
&&
.MARINE...
A weak surface low located off the coast of Mississippi will
slowly drift southeast and dissipate. High pressure will build over
our coastal waters giving way to typical summertime winds and
seas.
&&
.FIRE WEATHER...
Red Flag conditions are not anticipated this week.
&&
.HYDROLOGY...
In general, all area rivers currently in "Action" or flood stage
should either remain steady or gradually continue to lower over the
next several days. Widespread heavy rains are not anticipated,
though scattered heavy showers will be possible. Should one of these
storms form over or just upstream of our river system, sharp rises
will be possible. This was evident this afternoon along the Pea
River. The most notable river currently in flood is the
Choctawhatchee River near Bruce, which is expected to remain in
moderate flood stage through at least Thursday morning.
More specific stage information, as well as the latest river
forecasts can be found at the following link:
http://goo.gl/Lpg4a1
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 92 72 95 72 91 / 40 20 30 20 40
Panama City 90 76 90 77 88 / 30 20 30 20 30
Dothan 93 72 96 72 92 / 20 20 20 20 40
Albany 93 72 96 72 92 / 30 20 20 20 40
Valdosta 92 70 97 72 91 / 40 30 40 30 40
Cross City 93 70 94 72 90 / 30 10 40 30 50
Apalachicola 89 76 88 76 88 / 30 10 30 20 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Wool
SHORT TERM...Navarro/Harrigan
LONG TERM...Gould
AVIATION...Wool
MARINE...Navarro/Harrigan
FIRE WEATHER...Wool
HYDROLOGY...Harrigan
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
137 PM EDT MON JUL 29 2013
.PREV DISCUSSION... /ISSUED 1000 AM EDT MON JUL 29 2013/
UPDATE...
WEAK FRONT IS CURRENTLY DRAPED ACROSS CENTRAL GA. NOT MUCH OF A
WIND SHIFT/TEMP GRADIENT WITH THE BOUNDARY...BUT A DEFINITE DEWPOINT
GRADIENT EXISTS. CONVECTION MOST LIKELY ALONG AND SOUTH OF THE
BOUNDARY TODAY. A FEW STORMS COULD BECOME STRONG PRODUCING GUSTY
WINDS AND LIGHTNING STRIKES. THE POTENTIAL FOR SEVERE STORMS IS
LOW...BUT THE 12Z MODIFIED SOUNDING DOES SHOW SOMEWHAT OF AN
INVERTED V STRUCTURE...SO IF AN ISOLATED SEVERE STORM DOES
DEVELOP...A WET MICROBURST WILL BE POSSIBLE.
PREV DISCUSSION... /ISSUED 738 AM EDT MON JUL 29 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH TUESDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
&&
.AVIATION...
18Z UPDATE...
CONVECTION SHOULD MAINLY REMAIN SOUTH OF ATL TODAY AND TOMORROW.
NO CIG/VSBY RESTRICTIONS EXPECTED AT THE NORTHERN TERMINALS...BUT
SOME PATCHY FOG IS POSSIBLE AT THE SOUTHERN SITES. TOWARDS
SUNRISE...THE MODELS ARE PROGGING A BRIEF WIND SHIFT TO THE
NE...BUT SPEEDS SHOULD BE BLO 6 KT. WILL LEAVE OUT OF TAFS FOR
NOW.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON WINDS. HIGH CONFIDENCE REMAINING ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 69 89 69 / 20 10 20 20
ATLANTA 87 68 88 70 / 10 10 20 20
BLAIRSVILLE 82 61 84 64 / 10 5 30 30
CARTERSVILLE 85 63 90 67 / 10 5 10 30
COLUMBUS 91 73 93 72 / 30 20 20 20
GAINESVILLE 87 67 86 70 / 10 5 20 30
MACON 91 71 92 69 / 40 20 20 20
ROME 88 63 91 67 / 10 5 10 30
PEACHTREE CITY 87 66 88 65 / 10 10 20 20
VIDALIA 92 74 90 72 / 50 30 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....ATWELL
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1000 AM EDT MON JUL 29 2013
.UPDATE...
WEAK FRONT IS CURRENTLY DRAPED ACROSS CENTRAL GA. NOT MUCH OF A
WIND SHIFT/TEMP GRADIENT WITH THE BOUNDARY...BUT A DEFINITE DEWPOINT
GRADIENT EXISTS. CONVECTION MOST LIKELY ALONG AND SOUTH OF THE
BOUNDARY TODAY. A FEW STORMS COULD BECOME STRONG PRODUCING GUSTY
WINDS AND LIGHTNING STRIKES. THE POTENTIAL FOR SEVERE STORMS IS
LOW...BUT THE 12Z MODIFIED SOUNDING DOES SHOW SOMEWHAT OF AN
INVERTED V STRUCTURE...SO IF AN ISOLATED SEVERE STORM DOES
DEVELOP...A WET MICROBURST WILL BE POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 738 AM EDT MON JUL 29 2013/
PREV DISCUSSION...
SHORT TERM /TODAY THROUGH TUESDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
AVIATION...
12Z UPDATE...
FOG THIS MORNING HAS MAINLY BEEN LIMITED TO MCN AND AHN. LOW
CLOUDS HAVE BEEN SPORADIC IN LOCATION. WENT AHEAD AND MENTIONED
FEW030 AT ATL BASED ON HISTORY OF OBS...THOUGH ON THE FENCE ABOUT
WHETHER THE FEW WILL COME BACK THIS MORNING. OTHERWISE SHOULD SEE
CU DEVELOPMENT THIS AFTERNOON. CONVECTIVE ACTIVITY SHOULD BE
LIMITED TO CENTRAL GEORGIA THIS AFTERNOON BUT MAINLY ISOLD IN
COVERAGE. NOT ENOUGH OF A CHANCE TO EVEN MENTION AT MCN IN THE TAF.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON WIND AND VSBYS. MEDIUM CONFIDENCE ON CIGS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 69 / 20 5 20 20
ATLANTA 87 67 88 70 / 10 5 10 20
BLAIRSVILLE 82 60 84 64 / 5 5 20 30
CARTERSVILLE 85 61 90 67 / 5 5 10 30
COLUMBUS 91 70 93 72 / 20 5 20 20
GAINESVILLE 87 67 86 70 / 5 5 20 30
MACON 91 67 92 69 / 20 10 20 20
ROME 88 61 91 67 / 5 5 10 30
PEACHTREE CITY 87 62 88 65 / 10 5 20 20
VIDALIA 92 73 90 72 / 30 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
738 AM EDT MON JUL 29 2013
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH TUESDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
/ISSUED 404 AM EDT MON JUL 29 2013/
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
&&
.AVIATION...
12Z UPDATE...
FOG THIS MORNING HAS MAINLY BEEN LIMITED TO MCN AND AHN. LOW
CLOUDS HAVE BEEN SPORADIC IN LOCATION. WENT AHEAD AND MENTIONED
FEW030 AT ATL BASED ON HISTORY OF OBS...THOUGH ON THE FENCE ABOUT
WHETHER THE FEW WILL COME BACK THIS MORNING. OTHERWISE SHOULD SEE
CU DEVELOPMENT THIS AFTERNOON. CONVECTIVE ACTIVITY SHOULD BE
LIMITED TO CENTRAL GEORGIA THIS AFTERNOON BUT MAINLY ISOLD IN
COVERAGE. NOT ENOUGH OF A CHANCE TO EVEN MENTION AT MCN IN THE TAF.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON WIND AND VSBYS. MEDIUM CONFIDENCE ON CIGS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 69 / 20 5 20 20
ATLANTA 87 67 88 70 / 10 5 10 20
BLAIRSVILLE 82 60 84 64 / 5 5 20 30
CARTERSVILLE 85 61 90 67 / 5 5 10 30
COLUMBUS 91 70 93 72 / 20 5 20 20
GAINESVILLE 87 67 86 70 / 5 5 20 30
MACON 91 67 92 69 / 20 10 20 20
ROME 88 61 91 67 / 5 5 10 30
PEACHTREE CITY 87 62 88 65 / 10 5 20 20
VIDALIA 92 73 90 72 / 30 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....ARG
AVIATION...11
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
404 AM EDT MON JUL 29 2013
.SHORT TERM /TODAY THROUGH TUESDAY/...
A WEAK BOUNDARY CAN BE NOTED IN DEW POINTS THIS MORNING STRETCHING
ACROSS NORTH GEORGIA. IT APPEARS IT HASNT MADE IT TO ATL AND AHN
YET. A FEW SHOWERS DID FIRE UP LAST NIGHT JUST AHEAD OF THIS DRIER
AIR BUT HAVE DISSIPATED ACROSS THE CWA. THE DRIER AIR WILL CONTINUE
TO FILTER INTO NORTH GEORGIA TODAY WITH DEW POINTS IN THE MID 50S
EXPECTED FOR THIS AFTERNOON. SHOULD BE A PLEASANT DAY FOR NORTH
GEORGIA IN REGARDS TO HUMIDITY. WITH THE LOWER DEW POINTS AND HIGH
PRESSURE BUILDING INTO THE CWA...DO NOT EXPECT CONVECTION ACROSS
MOST OF NORTH GEORGIA THIS AFTERNOON. SLIGHTLY DIFFERENT STORY FOR
CENTRAL GEORGIA THOUGH. IT APPEARS THAT THE DRIER AIR WILL NOT QUITE
MAKE IT INTO THAT PART OF THE STATE. WITH THE BETTER MOISTURE AHEAD
OF THE WEAK SFC BOUNDARY...MODELS ARE ALL CONSISTENT WITH TRYING TO
PEG SOME ACCUMULATED PRECIP ACROSS CENTRAL GEORGIA...ALTHOUGH MOS
GUIDANCE VALUES ARE FAIRLY LOW...ABOUT 10 PERCENT. WENT SLIGHTLY
ABOVE GUIDANCE WITH GENERALLY A SLIGHT CHANCE FOR CENTRAL GEORGIA.
INITIAL RUNS OF THE HRRR WERE SHOWING CONVECTIVE INITIATION JUST SOUTH
OF THE METRO AREA BUT HAVE SHIFTED FURTHER SOUTH INTO CENTRAL
GEORGIA WHICH IS IN LINE WITH THE POP AREA FORECAST FOR TODAY. HRRR
DOES APPEAR TO DEVELOP A BIT OF CONVECTIVE ACTIVITY AND GIVEN THAT
SOLUTION...SLIGHT CHANCE POPS MAY BE SLIGHTLY UNDERDONE. ALSO THE
GFS DOES SHOW A VORT MAX MOVING THROUGH NORTH GEORGIA THIS MORNING
AND TYPICALLY WOULD SHOW BETTER RAIN CHANCES WITH THIS...HOWEVER
WITH THE DRY AIR IN PLACE...THINK THAT WILL HELP TO LIMIT CONVECTION.
IN ADDITION...THE ECMWF IS MUCH WEAKER WITH THIS WAVE...ALTHOUGH IT
DOES DEPICT IT WITH SIMILAR TIMING.
ANY ACTIVITY THAT DOES DEVELOP ACROSS CENTRAL GEORGIA SHOULD WEAKEN
QUICKLY TONIGHT WITH THE LOSS OF DAYTIME HEATING. BY TUESDAY AXIS OF
THE SFC HIGH WILL BE OVER EASTERN GA AND SFC HIGH WILL CONTINUE TO
DOMINATE. SOME WEAK PERTURBATIONS IN THE FLOW ALOFT...BUT OVERALL
CONVECTION SHOULD BE LIMITED AGAIN ON TUESDAY WITH BETTER CHANCES
ACROSS CENTRAL AND EASTERN GEORGIA.
MAXIMUM TEMPERATURES ARE FORECAST TO BE A FEW DEGREES BELOW NORMAL
TODAY. FOR TUESDAY MORNING...WE WILL SEE THE COOLER LOW TEMPERATURES
MAKE IT FURTHER SOUTH WITH LOWS MAKING IT INTO THE LOWER 60S ACROSS
PORTIONS OF NORTH CENTRAL GEORGIA. LOWS TUESDAY MORNING WILL BE
BELOW NORMAL.
11
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
ZONAL FLOW ACROSS THE EASTERN TWO THIRDS OF THE COUNTRY IN PLACE
AT THE BEGINNING OF THE PERIOD. FLOW WILL TRANSITION TO NORTHWEST
FLOW THROUGH MID WEEK AND INTO THE WEEKEND. NORTHWEST FLOW WILL
REMAIN THROUGH THE EXTENDED FORECAST. WITH THE DRIER AIR IN PLACE
FROM THE COLD FRONT THIS PAST WEEKEND THERE IS A SLIGHT CHANCE OF
DAYTIME STORMS UNTIL A WEAK WAVE MOVES INTO THE AREA ON WEDNESDAY.
THIS WAVE LEADS TO AN INCREASED CHANCE OF POPS AND THUNDER ON
WEDNESDAY. A SHORTWAVE EMBEDDED IN THE LARGER TROUGH WILL BRING
ANOTHER COLD FRONT INTO THE AREA THURSDAY OF NEXT WEEK. BEHIND
THIS FRONT IS DRIER AIR. TOWARDS THE END OF THE PERIOD...MOISTURE
ASSOCIATED WITH THE REMNANTS OF DORIAN ARE FORECAST TO ONCE AGAIN
INCREASE THE LIKELIHOOD OF PRECIP NEXT WEEKEND.
THAT BEING SAID...WE LOOK TO HAVE ONE MAYBE TWO DAYS OF LOW POPS
THROUGH THE EXTENDED. THE BEST CHANCE OF THUNDER APPEARS TO BE ON
THURSDAY WITH DAYTIME HEATING IN FRONT OF THE COLD FRONT. AT THIS
TIME IT DOES NOT APPEAR THERE WILL BE ORGANIZED SEVERE WEATHER IN
THE EXTENDED.
ARG
&&
.PREV DISCUSSION... /ISSUED 152 AM EDT MON JUL 29 2013/
AVIATION...
06Z UPDATE...
A FEW SHOWERS ACROSS THE AREA BUT VERY ISOLATED IN NATURE AND
SHORT LIVED. ALTHOUGH A SHOWER IS POSSIBLE THIS MORNING NEAR A TAF
SITE...CHANCES ARE VERY LOW. SOME UNCERTAINTY IN THE CIG AND VSBY
FORECAST AGAIN THIS MORNING. STARTING TO SEE SCT040 IN THE ATL
AREA AND IT IS POSSIBLE THAT SOME LOWER CLOUDS OF 020-025 COULD
DEVELOP ACROSS THE AREA BY LATER THIS MORNING. IFR TO MVFR FOG IS
EXPECTED THIS MORNING...BUT THAT SHOULD BE MAINLY LIMITED TO MCN
AND AHN...WITH A POSSIBILITY OF MVFR AT FTY AND PDK.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON CIGS AND VSBYS. HIGH CONFIDENCE ON WINDS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 69 / 20 5 20 20
ATLANTA 87 67 88 70 / 10 5 10 20
BLAIRSVILLE 82 60 84 64 / 5 5 20 30
CARTERSVILLE 85 61 90 67 / 5 5 10 30
COLUMBUS 91 70 93 72 / 20 5 20 20
GAINESVILLE 87 67 86 70 / 5 5 20 30
MACON 91 67 92 69 / 20 10 20 20
ROME 88 61 91 67 / 5 5 10 30
PEACHTREE CITY 87 62 88 65 / 10 5 20 20
VIDALIA 92 73 90 72 / 30 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....ARG
AVIATION...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
152 AM EDT MON JUL 29 2013
.PREV DISCUSSION...
UPDATE...
/ISSUED 1041 PM EDT SUN JUL 28 2013/
ONLY A FEW SHOWERS REMAIN FROM AHN TO CORDELE AND THESE ARE ON THE
DYING TREND. BY 06Z IT SHOULD BE DRY ACROSS THE CWA. MADE MINOR
ADJUSTMENTS TO THE POPS. NO OTHER CHANGES PLANNED.
SHORT TERM /TONIGHT THROUGH MONDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
WEAK FRONTAL BOUNDARY DRAPED ACROSS THE CENTRAL CWFA THIS AFTERNOON.
LOW PRESSURE AND A WARM FRONT ARE SITUATED ACROSS THE FLORIDA
PANHANDLE. ISO/SCT CONVECTION HAS DEVELOPED AHEAD OF THE WAVE OF LOW
PRESSURE DOWN SOUTH. THIS ACTIVITY SHOULD AFFECT MAINLY AREAS ALONG
THE SOUTHERN CWFA BORDER. ISOLD SHRA HAVE DEVELOPED ACROSS NORTHEAST
GA IN THE HIGHER TERRAIN. WILL HAVE TO WATCH THE SHRA/TSRA IN THE SW
CORNER OF THE CWFA...MAY HAVE TO UP THE POPS TO LIKELY IF THE
ACTIVITY KEEPS SPREADING.
LATEST RUN OF THE HRRR DOESN`T DO MUCH WITH THE CONVECTION UP
NORTH...BUT KEEPS THE SOUTHERN ACTIVITY GOING UNTIL AROUND SUNSET.
THE POTENTIAL FOR SEVERE REMAINS LOW...BUT ANY THUNDERSTORM THAT
DEVELOPS WILL HAVE THE POTENTIAL TO PRODUCE LIGHTNING STRIKES AND
GUSTY WINDS.
HRRR DIMINISHES CONVECTION AFTER SUNSET AND KEEPS THE NIGHTTIME
MOSTLY DRY. SOME PATCHY FOG IS POSSIBLE...WITH THE SATURATED GROUND
AND COOLER OVERNIGHT LOWS.
WEAK...MOSTLY DIFFUSE...FRONTAL BOUNDARY REMAINS ACROSS THE SOUTHERN
CWFA TOMORROW. DRIER AIR DOES SETTLE ON THE NORTHERN SIDE OF THE
BOUNDARY. HOWEVER...SLIGHTLY HIGHER DEWPOINTS WILL REMAIN ACROSS THE
SOUTH. MOISTURE WILL CONTINUE TO POOL ALONG THE WEAK BOUNDARY...BUT
WITH WEAK FORCING AND MARGINAL INSTABILITY...CONVECTION IS EXPECTED
TO BE LIMITED AGAIN TOMORROW.
NLISTEMAA
LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
/ISSUED AT 335 PM EDT SUN JUL 28 2013/
ADDED SLIGHT CHANCE POPS IN PORTIONS OF THE NORTH TUESDAY DUE TO
OROGRAPHIC ENHANCEMENT WITH RELATIVELY LIGHT WINDS WITH ANY LOW
LEVEL MOISTURE. HAVE MADE OTHER MINOR ADJUSTMENTS TO TEMPS BASED
ON LATEST BLEND OF GUIDANCE...OTHERWISE FORECAST LOOKS TO BE ON
TRACK AND PREVIOUS DISCUSSION FOLLOWS...
BAKER
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 359 AM EDT SUN JUL 28 2013/
LARGE SCALE PATTERN NOT FCST TO CHANGE MUCH DURING THE LONG TERM
PERIOD. UNUSUALLY ACTIVE WESTERLIES ACROSS THE CONUS WITH LONG
WAVE TROUGHING OVER THE EAST WILL CONTINUE. AFTER A BRIEF DRY
PERIOD WITH RISING HEIGHTS IN THE MID LEVELS...APPEARS THAT
WESTERLIES WILL DROP BACK DOWN INTO THE SE BY WED MORNING
CONTINUING THRU AT LEAST THUR NIGHT. BACK TO THE RAIN WE GO. BEST
CHC APPEARS TO BE WED AFT THRU THURS AFT. HEIGHTS PROGGED TO RISE
AGAIN ON FRI BUT THE WESTERLIES WILL BE JUST TO OUR NORTH.
GFS/ECMWF SHOW A COLD FRONT JUST TO OUR NORTH IN TN. MOISTURE FROM
REMNANTS OF DORIAN ALSO PROGGED BY LATE FRI AND SAT TO PUSH NORTH
INTO THE EASTERN GULF AND NRN FL AND MUCH OF GA.
ALL THIS SAID...NOT SEEING ANY SIGN OF SIGNIFICANT HEAVY RAIN OR SVR
WX. PW VALUES HIGH BUT NOT ANYTHING UNUSUALLY HIGH FOR THIS TIME OF
YEAR WITH VALUES AROUND 1.5 IN TUE/WED INCREASING TO 1.5-2.0 IN
THUR/FRI/SAT. SFC DEWPOINTS GREATER THAN 70 AND MLCAPE GREATER THAN
800 J/KG FCST TO REMAIN CONFINED TO SE COUNTIES THRU THURS THEN
SPREADING AREA WIDE FRI. COULD SEE SIGNIFICANT INSTABILITY BY NEXT
WEEKEND BASED ON 00Z GFS.
SNELSON
&&
.AVIATION...
06Z UPDATE...
A FEW SHOWERS ACROSS THE AREA BUT VERY ISOLATED IN NATURE AND
SHORT LIVED. ALTHOUGH A SHOWER IS POSSIBLE THIS MORNING NEAR A TAF
SITE...CHANCES ARE VERY LOW. SOME UNCERTAINTY IN THE CIG AND VSBY
FORECAST AGAIN THIS MORNING. STARTING TO SEE SCT040 IN THE ATL
AREA AND IT IS POSSIBLE THAT SOME LOWER CLOUDS OF 020-025 COULD
DEVELOP ACROSS THE AREA BY LATER THIS MORNING. IFR TO MVFR FOG IS
EXPECTED THIS MORNING...BUT THAT SHOULD BE MAINLY LIMITED TO MCN
AND AHN...WITH A POSSIBILITY OF MVFR AT FTY AND PDK.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON CIGS AND VSBYS. HIGH CONFIDENCE ON WINDS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 68 90 69 / 20 5 20 20
ATLANTA 87 68 88 70 / 10 5 10 20
BLAIRSVILLE 82 61 84 63 / 5 5 20 30
CARTERSVILLE 87 61 89 67 / 5 5 10 20
COLUMBUS 92 72 92 72 / 20 5 20 20
GAINESVILLE 87 68 86 69 / 5 5 20 20
MACON 91 69 91 69 / 20 10 20 20
ROME 87 61 89 68 / 5 5 10 30
PEACHTREE CITY 88 62 89 65 / 10 5 20 20
VIDALIA 91 73 90 73 / 20 20 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....ARG
AVIATION...11
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1031 PM EDT TUE JUL 30 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 253 PM EDT TUE JUL 30 2013
A WEAK SURFACE WAVE AND AN ASSOCIATED FRONTAL BOUNDARY WILL TRACK
THROUGH THE TENNESSEE AND LOWER OHIO VALLEYS INTO WEDNESDAY...
BRINGING THE CHANCE FOR RAIN SHOWERS. HIGH PRESSURE WILL BUILD
ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY ON THURSDAY WITH DRY
PLEASANT WEATHER. STORM CHANCES WILL RETURN TO THE REGION LATE
FRIDAY THROUGH SATURDAY AND AGAIN EARLY NEXT WEEK AS A FRONTAL
BOUNDARY SETS UP FROM THE CENTRAL PLAINS INTO THE LOWER OHIO VALLEY.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1004 PM EDT TUE JUL 30 2013
MAIN RAIN SHIELD HAS PASSED OFF TO THE SOUTHEAST OF THE FORECAST
AREA WHERE THE BEST UPPER SUPPORT IS. SCATTERED SHOWERS CONTINUE
ACROSS MAINLY THE NORTHERN HALF OF THE FORECAST AREA AT THE MOMENT
AS WEAK ISENTROPIC LIFT PERSISTS.
WEAK ISENTROPIC LIFT WILL CONTINUE OVERNIGHT SO CONTINUED WITH
CHANCE POPS ACROSS THE NORTH. ACROSS THE SOUTH...EXPECT ADDITIONAL
DEVELOPMENT OF SHOWERS AS A SURFACE LOW MOVES INTO THE OHIO VALLEY.
HOWEVER...FORCING IS NOT IMPRESSIVE ACROSS THE AREA...SO FEEL THAT
COVERAGE WILL NOT BE HIGH ENOUGH FOR LIKELY CATEGORY. THUS ONLY WENT
CHANCE POPS ACROSS THE SOUTH AS WELL.
TEMPERATURES LOOK GOOD AS ATMOSPHERE HAS MOISTENED UP THIS EVENING
AND EXTENSIVE CLOUD COVER WILL PERSIST.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 253 PM EDT TUE JUL 30 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WEDNESDAY AND AGAIN
FRIDAY AND TEMPS THROUGH THE PERIOD.
BACK EDGE OF THE DEEPER MOISTURE WILL BE PROGRESSING THROUGH EASTERN
COUNTIES ON WEDNESDAY MORNING AS WEAK SURFACE WAVE WITH THE
ASSOCIATED FRONTAL BOUNDARY TRACK THROUGH THE TENNESSEE VALLEY. MORE
WIDESPREAD AREA OF RAINFALL OVER SOUTHEAST COUNTIES TO START WILL
MOVE AWAY TO THE EAST AS THE MORNING PROGRESSES. WHILE LOW LEVEL
MOISTURE WILL LINGER ACROSS THE FORECAST AREA ALL DAY...ISENTROPIC
LIFT SHIFTS EAST BY MIDDAY WEDNESDAY WITH LITTLE ADDITIONAL FORCING
LEFT IN ITS WAKE. WILL MAINTAIN LOW CHANCE POPS INTO WEDNESDAY
EVENING AS PRESENCE OF WEAK INSTABILITY AND THE LOW LEVEL MOISTURE
COMBINED WITH THE PASSAGE OF A SECONDARY FRONT LATE WEDNESDAY
EVENING COULD PRODUCE ISOLATED TO SCATTERED CONVECTION. ABUNDANT
CLOUD COVER WILL PERSIST INTO WEDNESDAY NIGHT AS DEEPER MOISTURE
DOES NOT SHIFT EAST UNTIL THE PASSAGE OF THE SECONDARY BOUNDARY.
HIGH PRESSURE WILL EXPAND INTO THE REGION ON THURSDAY WITH DRY
NORTHWEST FLOW PROVIDING FOR YET ANOTHER COMFORTABLE DAY BY EARLY
AUGUST STANDARDS. DESPITE THE DRIER AIRMASS...CONVECTIVE TEMPS IN
THE UPPER 70S AND PASSAGE OF A WEAK WAVE ALOFT TO THE NORTH SUPPORT
THE LIKELY DEVELOPMENT OF A CU FIELD FOR THE AFTERNOON HOURS. UPPER
LEVEL PATTERN THURSDAY INTO FRIDAY WILL REVERT TO A FAMILIAR PATTERN
THROUGH THE SPRING AND SUMMER THIS YEAR AS A ROBUST RIDGE ALOFT
SETS UP OVER THE SOUTHERN HIGH PLAINS WHILE THE UPPER TROUGH ONCE
AGAIN ALIGNS OVER JAMES BAY. THIS WILL PLACE THE OHIO VALLEY WITHIN
A NORTHWEST FLOW ALOFT WITH A FRONTAL BOUNDARY SETTING UP FROM THE
CENTRAL PLAINS INTO THE TENNESSEE/LOWER OHIO VALLEY. AN UPPER LEVEL
WAVE WILL TRACK OUT OF THE DAKOTAS EARLY FRIDAY AND INTO THE REGION
BY FRIDAY NIGHT. MODELS EXHIBITING DISCREPANCIES WITH RESPECT TO
TIMING AND TRACK OF THE FEATURE AND SUBSEQUENTLY THE POTENTIAL
IMPACTS TO CENTRAL INDIANA. AT THIS POINT WITH THE HIGH
UNCERTAINTY...HAVE INTRODUCED LOW CHANCE POPS FRIDAY AFTERNOON.
TEMPS...COOL PATTERN WILL PERSIST THROUGH THE PERIOD...FIRST DUE TO
THE CLOUDS AND SCATTERED PRECIP LINGERING WEDNESDAY...THEN TO THE
NORTHWEST FLOW ACROSS THE REGION THURSDAY/FRIDAY. CONSALL GENERALLY
MATCHED LOW LEVEL THERMALS WELL AND ENDED UP IN BETWEEN THE WARMER
MAV AND COOLER MET GUIDANCE. EXPECT MOST OF THE AREA TO REMAIN IN
THE 70S FOR HIGHS WEDNESDAY WITH POTENTIAL FOR LOWER 80S THURSDAY/
FRIDAY. MAVMOS LARGELY LOOKED REASONABLE FOR OVERNIGHT LOWS THROUGH
THE PERIOD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 230 PM EDT TUE JUL 30 2013
CONFIDENCE REMAINS LOW FOR ANY PRECIP EVENT.
GFS AND ECMWF CONTINUE TO KEEP A NW FLOW IN PLACE ALOFT DURING
THIS PERIOD AND CONTINUE TO INDICATE POORLY DEFINED AND WEAK
DISTURBANCES PUSHING THROUGH THE FLOW. AGAIN AT THE SURFACE MAINLY A
VERY BROAD AREA OF HIGH PRESSURE LOOKS TO REMAIN IN
PLACE...HOWEVER A WEAK BOUNDARY APPEARS TO SET UP BETWEEN A HIGH
TO THE SOUTH AND ANOTHER HIGH PRESSURE SYSTEM TO THE NORTH. GIVEN
THE LACK OF UPPER SUPPORT AND THE LACK OF MOISTURE...TRENDING ANY
POPS AS LOW AS ALLBLEND WILL ALLOW ME TO AS THE PRECIP SEEMS
OVERDONE.
GIVEN THE COOL ALOFT NW FLOW...WILL CONTINUE TO TREND TEMPS AT OR
BELOW MEXMOS.
&&
.AVIATION /DISCUSSION FOR THE 31/03Z TAF UPDATE/...
ISSUED AT 1031 PM EDT TUE JUL 30 2013
NO SIGNIFICANT CHANGES REQUIRED. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 708 PM EDT TUE JUL 30 2013
VFR TO START AT IND/LAF...WITH MVFR OR AT LEAST TEMPO MVFR STARTING
AT HUF AND BMG. CONDITIONS EXPECTED TO DETERIORATE LATER THIS
EVENING AS VARIOUS MODEL FIELDS AND LAMP GUIDANCE DEPICT WIDESPREAD
IFR UPSTREAM SPREADING INTO THE AREA AS A WEAK SURFACE WAVE
APPROACHES. CEILINGS ARE THE MOST IMMEDIATE CONCERN...ALTHOUGH
VISIBILITIES COULD DROP SIGNIFICANTLY IN SOME AREAS AS WELL.
THESE SITUATIONS ALMOST ALWAYS INVOLVE FLUCTUATIONS...BUT WILL GO NO
LOWER THAN IFR AT THIS TIME. NEAR DAYBREAK...CANNOT RULE OUT
DROPPING INTO LIFR OR EVEN VLIFR CONDITIONS FOR A TIME...BUT
CONFIDENCE IN THIS IS LOW FOR THE MOMENT.
CEILINGS SHOULD BEGIN TO IMPROVE FROM LATE MORNING ON ACROSS THE
AREA AS THE SURFACE WAVE MAKES PROGRESS EASTWARD.
EXPECT THAT SHOWERS ACROSS THE AREA WILL MAINLY IMPACT THE SITES
DURING THE FIRST FEW HOURS OF THE PERIOD...AND WILL CARRY ONLY VCSH
LATER IN THE EVENING AS HRRR DEPICTS A CONTINUED DISSIPATION TREND
FROM WHAT HAS ALREADY OCCURRED.
WINDS WILL GENERALLY BE SOUTHEASTERLY AND WELL BELOW 10KT
OVERNIGHT...BECOMING NORTHWESTERLY BUT REMAINING WELL BELOW 10KT
TOMORROW AFTERNOON AS THE SURFACE WAVE PASSES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...50
SHORT TERM...RYAN
LONG TERM....PUMA
AVIATION...NIELD
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
1004 PM EDT TUE JUL 30 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 253 PM EDT TUE JUL 30 2013
A WEAK SURFACE WAVE AND AN ASSOCIATED FRONTAL BOUNDARY WILL TRACK
THROUGH THE TENNESSEE AND LOWER OHIO VALLEYS INTO WEDNESDAY...
BRINGING THE CHANCE FOR RAIN SHOWERS. HIGH PRESSURE WILL BUILD
ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY ON THURSDAY WITH DRY
PLEASANT WEATHER. STORM CHANCES WILL RETURN TO THE REGION LATE
FRIDAY THROUGH SATURDAY AND AGAIN EARLY NEXT WEEK AS A FRONTAL
BOUNDARY SETS UP FROM THE CENTRAL PLAINS INTO THE LOWER OHIO VALLEY.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1004 PM EDT TUE JUL 30 2013
MAIN RAIN SHIELD HAS PASSED OFF TO THE SOUTHEAST OF THE FORECAST
AREA WHERE THE BEST UPPER SUPPORT IS. SCATTERED SHOWERS CONTINUE
ACROSS MAINLY THE NORTHERN HALF OF THE FORECAST AREA AT THE MOMENT
AS WEAK ISENTROPIC LIFT PERSISTS.
WEAK ISENTROPIC LIFT WILL CONTINUE OVERNIGHT SO CONTINUED WITH
CHANCE POPS ACROSS THE NORTH. ACROSS THE SOUTH...EXPECT ADDITIONAL
DEVELOPMENT OF SHOWERS AS A SURFACE LOW MOVES INTO THE OHIO VALLEY.
HOWEVER...FORCING IS NOT IMPRESSIVE ACROSS THE AREA...SO FEEL THAT
COVERAGE WILL NOT BE HIGH ENOUGH FOR LIKELY CATEGORY. THUS ONLY WENT
CHANCE POPS ACROSS THE SOUTH AS WELL.
TEMPERATURES LOOK GOOD AS ATMOSPHERE HAS MOISTENED UP THIS EVENING
AND EXTENSIVE CLOUD COVER WILL PERSIST.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 253 PM EDT TUE JUL 30 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WEDNESDAY AND AGAIN
FRIDAY AND TEMPS THROUGH THE PERIOD.
BACK EDGE OF THE DEEPER MOISTURE WILL BE PROGRESSING THROUGH EASTERN
COUNTIES ON WEDNESDAY MORNING AS WEAK SURFACE WAVE WITH THE
ASSOCIATED FRONTAL BOUNDARY TRACK THROUGH THE TENNESSEE VALLEY. MORE
WIDESPREAD AREA OF RAINFALL OVER SOUTHEAST COUNTIES TO START WILL
MOVE AWAY TO THE EAST AS THE MORNING PROGRESSES. WHILE LOW LEVEL
MOISTURE WILL LINGER ACROSS THE FORECAST AREA ALL DAY...ISENTROPIC
LIFT SHIFTS EAST BY MIDDAY WEDNESDAY WITH LITTLE ADDITIONAL FORCING
LEFT IN ITS WAKE. WILL MAINTAIN LOW CHANCE POPS INTO WEDNESDAY
EVENING AS PRESENCE OF WEAK INSTABILITY AND THE LOW LEVEL MOISTURE
COMBINED WITH THE PASSAGE OF A SECONDARY FRONT LATE WEDNESDAY
EVENING COULD PRODUCE ISOLATED TO SCATTERED CONVECTION. ABUNDANT
CLOUD COVER WILL PERSIST INTO WEDNESDAY NIGHT AS DEEPER MOISTURE
DOES NOT SHIFT EAST UNTIL THE PASSAGE OF THE SECONDARY BOUNDARY.
HIGH PRESSURE WILL EXPAND INTO THE REGION ON THURSDAY WITH DRY
NORTHWEST FLOW PROVIDING FOR YET ANOTHER COMFORTABLE DAY BY EARLY
AUGUST STANDARDS. DESPITE THE DRIER AIRMASS...CONVECTIVE TEMPS IN
THE UPPER 70S AND PASSAGE OF A WEAK WAVE ALOFT TO THE NORTH SUPPORT
THE LIKELY DEVELOPMENT OF A CU FIELD FOR THE AFTERNOON HOURS. UPPER
LEVEL PATTERN THURSDAY INTO FRIDAY WILL REVERT TO A FAMILIAR PATTERN
THROUGH THE SPRING AND SUMMER THIS YEAR AS A ROBUST RIDGE ALOFT
SETS UP OVER THE SOUTHERN HIGH PLAINS WHILE THE UPPER TROUGH ONCE
AGAIN ALIGNS OVER JAMES BAY. THIS WILL PLACE THE OHIO VALLEY WITHIN
A NORTHWEST FLOW ALOFT WITH A FRONTAL BOUNDARY SETTING UP FROM THE
CENTRAL PLAINS INTO THE TENNESSEE/LOWER OHIO VALLEY. AN UPPER LEVEL
WAVE WILL TRACK OUT OF THE DAKOTAS EARLY FRIDAY AND INTO THE REGION
BY FRIDAY NIGHT. MODELS EXHIBITING DISCREPANCIES WITH RESPECT TO
TIMING AND TRACK OF THE FEATURE AND SUBSEQUENTLY THE POTENTIAL
IMPACTS TO CENTRAL INDIANA. AT THIS POINT WITH THE HIGH
UNCERTAINTY...HAVE INTRODUCED LOW CHANCE POPS FRIDAY AFTERNOON.
TEMPS...COOL PATTERN WILL PERSIST THROUGH THE PERIOD...FIRST DUE TO
THE CLOUDS AND SCATTERED PRECIP LINGERING WEDNESDAY...THEN TO THE
NORTHWEST FLOW ACROSS THE REGION THURSDAY/FRIDAY. CONSALL GENERALLY
MATCHED LOW LEVEL THERMALS WELL AND ENDED UP IN BETWEEN THE WARMER
MAV AND COOLER MET GUIDANCE. EXPECT MOST OF THE AREA TO REMAIN IN
THE 70S FOR HIGHS WEDNESDAY WITH POTENTIAL FOR LOWER 80S THURSDAY/
FRIDAY. MAVMOS LARGELY LOOKED REASONABLE FOR OVERNIGHT LOWS THROUGH
THE PERIOD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 230 PM EDT TUE JUL 30 2013
CONFIDENCE REMAINS LOW FOR ANY PRECIP EVENT.
GFS AND ECMWF CONTINUE TO KEEP A NW FLOW IN PLACE ALOFT DURING
THIS PERIOD AND CONTINUE TO INDICATE POORLY DEFINED AND WEAK
DISTURBANCES PUSHING THROUGH THE FLOW. AGAIN AT THE SURFACE MAINLY A
VERY BROAD AREA OF HIGH PRESSURE LOOKS TO REMAIN IN
PLACE...HOWEVER A WEAK BOUNDARY APPEARS TO SET UP BETWEEN A HIGH
TO THE SOUTH AND ANOTHER HIGH PRESSURE SYSTEM TO THE NORTH. GIVEN
THE LACK OF UPPER SUPPORT AND THE LACK OF MOISTURE...TRENDING ANY
POPS AS LOW AS ALLBLEND WILL ALLOW ME TO AS THE PRECIP SEEMS
OVERDONE.
GIVEN THE COOL ALOFT NW FLOW...WILL CONTINUE TO TREND TEMPS AT OR
BELOW MEXMOS.
&&
.AVIATION /DISCUSSION FOR THE 31/00Z TAFS/...
ISSUED AT 708 PM EDT TUE JUL 30 2013
VFR TO START AT IND/LAF...WITH MVFR OR AT LEAST TEMPO MVFR STARTING
AT HUF AND BMG. CONDITIONS EXPECTED TO DETERIORATE LATER THIS
EVENING AS VARIOUS MODEL FIELDS AND LAMP GUIDANCE DEPICT WIDESPREAD
IFR UPSTREAM SPREADING INTO THE AREA AS A WEAK SURFACE WAVE
APPROACHES. CEILINGS ARE THE MOST IMMEDIATE CONCERN...ALTHOUGH
VISIBILITIES COULD DROP SIGNIFICANTLY IN SOME AREAS AS WELL.
THESE SITUATIONS ALMOST ALWAYS INVOLVE FLUCTUATIONS...BUT WILL GO NO
LOWER THAN IFR AT THIS TIME. NEAR DAYBREAK...CANNOT RULE OUT
DROPPING INTO LIFR OR EVEN VLIFR CONDITIONS FOR A TIME...BUT
CONFIDENCE IN THIS IS LOW FOR THE MOMENT.
CEILINGS SHOULD BEGIN TO IMPROVE FROM LATE MORNING ON ACROSS THE
AREA AS THE SURFACE WAVE MAKES PROGRESS EASTWARD.
EXPECT THAT SHOWERS ACROSS THE AREA WILL MAINLY IMPACT THE SITES
DURING THE FIRST FEW HOURS OF THE PERIOD...AND WILL CARRY ONLY VCSH
LATER IN THE EVENING AS HRRR DEPICTS A CONTINUED DISSIPATION TREND
FROM WHAT HAS ALREADY OCCURRED.
WINDS WILL GENERALLY BE SOUTHEASTERLY AND WELL BELOW 10KT
OVERNIGHT...BECOMING NORTHWESTERLY BUT REMAINING WELL BELOW 10KT
TOMORROW AFTERNOON AS THE SURFACE WAVE PASSES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...50
SHORT TERM...RYAN
LONG TERM....PUMA
AVIATION...NIELD
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
708 PM EDT TUE JUL 30 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 253 PM EDT TUE JUL 30 2013
A WEAK SURFACE WAVE AND AN ASSOCIATED FRONTAL BOUNDARY WILL TRACK
THROUGH THE TENNESSEE AND LOWER OHIO VALLEYS INTO WEDNESDAY...
BRINGING THE CHANCE FOR RAIN SHOWERS. HIGH PRESSURE WILL BUILD
ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY ON THURSDAY WITH DRY
PLEASANT WEATHER. STORM CHANCES WILL RETURN TO THE REGION LATE
FRIDAY THROUGH SATURDAY AND AGAIN EARLY NEXT WEEK AS A FRONTAL
BOUNDARY SETS UP FROM THE CENTRAL PLAINS INTO THE LOWER OHIO VALLEY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 253 PM EDT TUE JUL 30 2013
RAIN SHIELD ASSOCIATED WITH A POORLY ORGANIZED SURFACE WAVE
CONTINUES TO MAKE SLOW EASTWARD PROGRESS INTO CENTRAL INDIANA THIS
AFTERNOON...AS DRIER AIR AND SOUTHEAST FLOW HAMPER MOISTURE
ADVECTION ACROSS THE REGION. MID/HIGH LEVEL CLOUD SHIELD HAD
ENCOMPASSED MUCH OF THE FORECAST AREA AS OF 18Z. CLOUDS HAD HELD
TEMPS DOWN THIS AFTERNOON...WITH MOST LOCATIONS HOLDING IN THE LOWER
AND MIDDLE 70S.
RAIN CHANCES REMAIN THE PRIMARY FOCUS OF THE NEAR TERM AS THE WEAK
SURFACE WAVE TRAVERSES ALONG A WARM FRONT THROUGH THE TENNESSEE AND
LOWER OHIO VALLEYS. RAIN HAVING A TOUGH TIME PROGRESSING EAST
QUICKLY DUE TO THE LACK OF MOISTURE. CURRENT IR SATELLITE INDICATING
THAT COLDER CLOUD TOPS HAVE SPLIT...FOCUSING FURTHER SOUTH OVER THE
LOWER OHIO VALLEY WHERE MOISTURE AND INSTABILITY ARE MORE
PREVALENT...WITH ANOTHER AREA OVER NORTHERN PORTIONS OF ILLINOIS/
NORTHWEST INDIANA IN CLOSER PROXIMITY TO SLIGHTLY BETTER FORCING
ALOFT. EXPECT THE AREA OF RAIN OVER NORTHERN ILLINOIS/NW INDIANA
WILL STEADILY WEAKEN IN TIME OVER THE NEXT FEW HOURS AS IT
EVENTUALLY SUCCUMBS TO THE DRIER AIR PRESENT ACROSS THE LOWER GREAT
LAKES. PRECIP AREA TO THE SOUTH ON THE OTHER HAND SHOULD CONTINUE
THROUGH TONIGHT AS LOW LEVEL FORCING INCREASES AFTER DARK AND
ISENTROPIC LIFT BRIEFLY STRENGTHENS ACROSS THE OHIO VALLEY. STILL
APPEARS THE NORTHERN EXTENT OF THE MORE WIDESPREAD RAINFALL SHOULD
IMPACT SOUTHERN COUNTIES THIS EVENING INTO THE OVERNIGHT...AND WILL
CONTINUE WITH LIKELY POPS. FURTHER NORTH HOWEVER IN THE ABSENCE OF
FORCING ALOFT...PRECIP LIKELY TO REMAIN LIGHT AND RELATIVELY
SCATTERED. HAVE LEANED MUCH CLOSER TO THE OP GFS SOLUTION REGARDING
PRECIP COVERAGE OVERNIGHT AS 12Z NAM APPEARS TO BE SIGNIFICANTLY
OVERDOING QPF AND MAY BE SUFFERING FROM CONVECTIVE FEEDBACK.
STORMS HAVE BEEN LARGELY NONEXISTENT WITH THIS WAVE SO FAR
TODAY...WITH ANY LIGHTNING BEING CONFINED TO THE VICINITY OF THE
WAVE AND BOUNDARY. WITH MODEL SOUNDINGS INDICATING LITTLE TO NO
INSTABILITY PRESENT OVER THE FORECAST AREA...HAVE REMOVED ANY
MENTION OF THUNDERSTORMS THROUGH THE PERIOD.
TEMPS...LEANED CLOSER TO THE WARMER METMOS GUIDANCE FOR OVERNIGHT
LOWS WITH CLOUDS/RAIN IMPACTING THE FORECAST AREA. EXPECT LOWS
MAINLY IN THE MID 60S.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 253 PM EDT TUE JUL 30 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WEDNESDAY AND AGAIN
FRIDAY AND TEMPS THROUGH THE PERIOD.
BACK EDGE OF THE DEEPER MOISTURE WILL BE PROGRESSING THROUGH EASTERN
COUNTIES ON WEDNESDAY MORNING AS WEAK SURFACE WAVE WITH THE
ASSOCIATED FRONTAL BOUNDARY TRACK THROUGH THE TENNESSEE VALLEY. MORE
WIDESPREAD AREA OF RAINFALL OVER SOUTHEAST COUNTIES TO START WILL
MOVE AWAY TO THE EAST AS THE MORNING PROGRESSES. WHILE LOW LEVEL
MOISTURE WILL LINGER ACROSS THE FORECAST AREA ALL DAY...ISENTROPIC
LIFT SHIFTS EAST BY MIDDAY WEDNESDAY WITH LITTLE ADDITIONAL FORCING
LEFT IN ITS WAKE. WILL MAINTAIN LOW CHANCE POPS INTO WEDNESDAY
EVENING AS PRESENCE OF WEAK INSTABILITY AND THE LOW LEVEL MOISTURE
COMBINED WITH THE PASSAGE OF A SECONDARY FRONT LATE WEDNESDAY
EVENING COULD PRODUCE ISOLATED TO SCATTERED CONVECTION. ABUNDANT
CLOUD COVER WILL PERSIST INTO WEDNESDAY NIGHT AS DEEPER MOISTURE
DOES NOT SHIFT EAST UNTIL THE PASSAGE OF THE SECONDARY BOUNDARY.
HIGH PRESSURE WILL EXPAND INTO THE REGION ON THURSDAY WITH DRY
NORTHWEST FLOW PROVIDING FOR YET ANOTHER COMFORTABLE DAY BY EARLY
AUGUST STANDARDS. DESPITE THE DRIER AIRMASS...CONVECTIVE TEMPS IN
THE UPPER 70S AND PASSAGE OF A WEAK WAVE ALOFT TO THE NORTH SUPPORT
THE LIKELY DEVELOPMENT OF A CU FIELD FOR THE AFTERNOON HOURS. UPPER
LEVEL PATTERN THURSDAY INTO FRIDAY WILL REVERT TO A FAMILIAR PATTERN
THROUGH THE SPRING AND SUMMER THIS YEAR AS A ROBUST RIDGE ALOFT
SETS UP OVER THE SOUTHERN HIGH PLAINS WHILE THE UPPER TROUGH ONCE
AGAIN ALIGNS OVER JAMES BAY. THIS WILL PLACE THE OHIO VALLEY WITHIN
A NORTHWEST FLOW ALOFT WITH A FRONTAL BOUNDARY SETTING UP FROM THE
CENTRAL PLAINS INTO THE TENNESSEE/LOWER OHIO VALLEY. AN UPPER LEVEL
WAVE WILL TRACK OUT OF THE DAKOTAS EARLY FRIDAY AND INTO THE REGION
BY FRIDAY NIGHT. MODELS EXHIBITING DISCREPANCIES WITH RESPECT TO
TIMING AND TRACK OF THE FEATURE AND SUBSEQUENTLY THE POTENTIAL
IMPACTS TO CENTRAL INDIANA. AT THIS POINT WITH THE HIGH
UNCERTAINTY...HAVE INTRODUCED LOW CHANCE POPS FRIDAY AFTERNOON.
TEMPS...COOL PATTERN WILL PERSIST THROUGH THE PERIOD...FIRST DUE TO
THE CLOUDS AND SCATTERED PRECIP LINGERING WEDNESDAY...THEN TO THE
NORTHWEST FLOW ACROSS THE REGION THURSDAY/FRIDAY. CONSALL GENERALLY
MATCHED LOW LEVEL THERMALS WELL AND ENDED UP IN BETWEEN THE WARMER
MAV AND COOLER MET GUIDANCE. EXPECT MOST OF THE AREA TO REMAIN IN
THE 70S FOR HIGHS WEDNESDAY WITH POTENTIAL FOR LOWER 80S THURSDAY/
FRIDAY. MAVMOS LARGELY LOOKED REASONABLE FOR OVERNIGHT LOWS THROUGH
THE PERIOD.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 230 PM EDT TUE JUL 30 2013
CONFIDENCE REMAINS LOW FOR ANY PRECIP EVENT.
GFS AND ECMWF CONTINUE TO KEEP A NW FLOW IN PLACE ALOFT DURING
THIS PERIOD AND CONTINUE TO INDICATE POORLY DEFINED AND WEAK
DISTURBANCES PUSHING THROUGH THE FLOW. AGAIN AT THE SURFACE MAINLY A
VERY BROAD AREA OF HIGH PRESSURE LOOKS TO REMAIN IN
PLACE...HOWEVER A WEAK BOUNDARY APPEARS TO SET UP BETWEEN A HIGH
TO THE SOUTH AND ANOTHER HIGH PRESSURE SYSTEM TO THE NORTH. GIVEN
THE LACK OF UPPER SUPPORT AND THE LACK OF MOISTURE...TRENDING ANY
POPS AS LOW AS ALLBLEND WILL ALLOW ME TO AS THE PRECIP SEEMS
OVERDONE.
GIVEN THE COOL ALOFT NW FLOW...WILL CONTINUE TO TREND TEMPS AT OR
BELOW MEXMOS.
&&
.AVIATION /DISCUSSION FOR THE 31/00Z TAFS/...
ISSUED AT 708 PM EDT TUE JUL 30 2013
VFR TO START AT IND/LAF...WITH MVFR OR AT LEAST TEMPO MVFR STARTING
AT HUF AND BMG. CONDITIONS EXPECTED TO DETERIORATE LATER THIS
EVENING AS VARIOUS MODEL FIELDS AND LAMP GUIDANCE DEPICT WIDESPREAD
IFR UPSTREAM SPREADING INTO THE AREA AS A WEAK SURFACE WAVE
APPROACHES. CEILINGS ARE THE MOST IMMEDIATE CONCERN...ALTHOUGH
VISIBILITIES COULD DROP SIGNIFICANTLY IN SOME AREAS AS WELL.
THESE SITUATIONS ALMOST ALWAYS INVOLVE FLUCTUATIONS...BUT WILL GO NO
LOWER THAN IFR AT THIS TIME. NEAR DAYBREAK...CANNOT RULE OUT
DROPPING INTO LIFR OR EVEN VLIFR CONDITIONS FOR A TIME...BUT
CONFIDENCE IN THIS IS LOW FOR THE MOMENT.
CEILINGS SHOULD BEGIN TO IMPROVE FROM LATE MORNING ON ACROSS THE
AREA AS THE SURFACE WAVE MAKES PROGRESS EASTWARD.
EXPECT THAT SHOWERS ACROSS THE AREA WILL MAINLY IMPACT THE SITES
DURING THE FIRST FEW HOURS OF THE PERIOD...AND WILL CARRY ONLY VCSH
LATER IN THE EVENING AS HRRR DEPICTS A CONTINUED DISSIPATION TREND
FROM WHAT HAS ALREADY OCCURRED.
WINDS WILL GENERALLY BE SOUTHEASERLY AND WELL BELOW 10KT
OVERNIGHT...BECOMING NORTHWESTERLY BUT REMAINING WELL BELOW 10KT
TOMORROW AFTERNOON AS THE SURFACE WAVE PASSES.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....PUMA
AVIATION...NIELD
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 GOODLAND KS
857 PM MDT TUE JUL 30 2013
.UPDATE...
ISSUED AT 847 PM MDT TUE JUL 30 2013
SMALL AREA OF THUNDERSTORMS OVER FRONTIER COUNTY CONTINUES TO MOVE
SOUTHWARD INTO THE DRIER AIR. DO NOT EXPECT IT TO SUDDENLY
DISSIPATE BEFORE REACHING RED WILLOW COUNTY SO HAVE FAIRLY HIGH
CHANCES FOR PRECIP. CHANCES THERE. PRECIP. CHANCES DECLINE
FURTHER SOUTH SINCE THE STORM WILL CONTINUE TO BE IN THE DRIER AIR
WHICH SHOULD CAUSE IT TO EVENTUALLY DISSIPATE COMPLETELY.
OVERNIGHT A PLUME OF MOISTURE AHEAD OF AN UPPER LEVEL
TROUGH...CURRENTLY OVER WYOMING...WILL MOVE OVER THE NORTHERN PART
OF THE AREA. SOUNDINGS SHOW SOME ELEVATED INSTABILITY AS THE SHORT
WAVE TROUGH MOVES THROUGH. AS A RESULT WILL HAVE SOME SLIGHT
CHANCES GOING DURING THE OVERNIGHT/EARLY MORNING HOURS AS THE
SHORT WAVE TROUGH MOVES THROUGH.
SOUNDINGS OVER THE EASTERN HALF OF THE AREA ARE STILL SUGGESTING
FOG DEVELOPMENT TONIGHT. DO NOT ANTICIPATE IT TO BE AS THICK AS THE
LAST COUPLE OF NIGHTS DUE TO THE RATHER SHALLOW DEPTH TO THE
SATURATION.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 PM MDT TUE JUL 30 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS ELONGATED RIDGE ACROSS
THE SOUTHERN PLAINS WITH WESTERLY FLOW IN PLACE ACROSS THE
CENTRAL/HIGH PLAINS. A WEAK LEE TROUGH IS CURRENTLY IN PLACE ACROSS
EASTERN COLORADO WITH A WEAK CONVERGENCE REGION EXTENDING INTO OUR
WESTERN CWA.
THIS WILL ACT AS THE FOCUS FOR ISOLATED THUNDERSTORM DEVELOPMENT
THIS AFTERNOON...WITH CU FIELD ALREADY IN PLACE AND RADAR INDICATING
SEVERAL DEVELOPING UPDRAFTS JUST NW OF OUR CWA NEAR YUMA COUNTY. WITH
STORM MOTIONS OUT OF THE EAST 10-20KT MOST STORMS WILL BE SLOW
MOVERS...THOUGH WE COULD STILL SEE THIS ACTIVITY MOVE FURTHER EAST
IN OUR CWA THROUGH THE AFTERNOON BEFORE FALLING APART AFTER SUNSET
WITH LOSS OF DAYTIME HEATING AND INCREASING LOW LEVEL CINH. LATEST
RAP ANALYSIS SHOWS SB/ML CAPE VALUES RANGING FROM 1000-1500
J/KG...AND WITH ADJUSTED SOUNDINGS SUPPORTING POSSIBLE CAPE VALUES
IN THE 2000-2500J/KG RANGE LATER THIS AFTERNOON. WITH HIGH TD
DEPRESSIONS TO ABOUT 700MB THROUGH A DRY ADIABATIC AIR MASS AND HIGH
LFC/LCL IN THE 10-13KFT RANGE WE COULD SEE STRONG THUNDERSTORM GUST
POTENTIAL. IF WE REALIZE THE HIGHER CAPE VALUES I COULDNT RULE OUT
LARGE HAIL POTENTIAL...HOWEVER AT THIS POINT STRONG WINDS ARE
PROBABLY THE GREATER THREAT WITH ANY THUNDERSTORMS THAT DEVELOP.
MET/MAV GUIDANCE ARE INDICATING FOG DEVELOPMENT TONIGHT...HOWEVER
WITH W-SW WINDS TO 10KT AT THE SURFACE AND BL WINDS IN EXCESS OF
20KT...I AM NOT AS CONFIDENT WE WILL SEE A REPEAT OF LAST NIGHT.
WITH TROUGH AXIS SHIFTING EAST WE COULD STILL SEE LIGHT SURFACE
WINDS IN THE EAST WHERE FOG WOULD BE MORE LIKELY TO OCCUR...AND
WHERE I KEPT PATCHY FOG MENTION.
A WEAK COLD FRONT WILL DROP SOUTH LATE TONIGHT AND STALL ALONG THE
NE/KS STATE LINE BY MIDDAY WEDNESDAY WITH A PRE FRONTAL TROUGH
SETTLING TO OUR SOUTHEAST. AHEAD OF THE TROUGH AXIS CAPE VALUES IN
EXCESS OF 2500 J/KG ARE ADVERTISED. THIS TROUGH AXIS WILL BE THE
MAIN FOCUS WITH GOOD SURFACE CONVERGENCE IN PLACE...AND I KEPT 30/40
POPS TIED TO THIS FEATURE...AND LOWER POPS TO THE NORTH. WITH BETTER
CAPE AND MARGINALLY BETTER SHEER WE WILL SEE A CHANCE FOR
THUNDERSTORMS TO BECOME BETTER ORGANIZED WITH SEVERE WIND/HAIL A
POSSIBILITY IN OUR SOUTHEAST DURING THE AFTERNOON.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 250 PM MDT TUE JUL 30 2013
NO MAJOR CHANGES SEEN TO THE UPPER PATTERN ACROSS THE SOUTHERN AND
CENTRAL PLAINS DURING THIS PERIOD. UPPER HIGH NOW CENTERED OVER
NEW MEXICO AND WAFFLE BACK AND FORTH OVER TO WEST TEXAS AND BACK DURING
PERIOD. ALTHOUGH THE UPPER RIDGE IS FORECAST TO ASSERT ITSELF SLIGHTLY
NORTH OVER THE MOUNTAINS...A SERIES OF WEAK UPPER IMPULSES WILL
CONTINUE TO MOVE OVER THE TOP OF THE RIDGE KEEPING IT FAIRLY
FLAT OVERALL.
THIS MAKES IT DIFFICULT TO ASSESS TIMING OF PRECIPITATION. ALL
GUIDANCE IS SUGGESTING AN ACTIVE FLOW REGIME WILL CONTINUE WITH
SLIGHT CHANCE TO CHANCE POPS EVERY DAY. RIGHT NOW THE MOST ACTIVE
PERIODS FOR PRECIPITATION LOOK TO BE THURSDAY NIGHT AND AGAIN
SATURDAY NIGHT. TEMPERATURES WILL CONTINUE SEASONAL WITH HIGHS
MOSTLY IN THE UPPER 80S TO LOWER 90S AND LOWS IN THE 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 531 PM MDT TUE JUL 30 2013
VFR TO POSSIBLY MVFR CONDITIONS ARE FORECAST FOR THE 0Z TAFS.
WINDS AT KGLD WILL SLOWLY SHIFT TO THE SOUTHEAST OVER THE NEXT
FEW HOURS AS THE DECAYING THUNDERSTORM SOUTHEAST OF KGLD CONTINUES
TO MOVE AWAY. OVERNIGHT KMCK MAY HAVE SOME PATCHY FOG AND LOW
CLOUDS. WEDNESDAY A WEAK FRONT/SURFACE TROUGH WILL MOVE INTO THE
AREA DURING THE MORNING. THE LIGHT WINDS WILL SHIFT TO THE NORTH
BEHIND THE SURFACE BOUNDARY. DURING THE AFTERNOON THUNDERSTORMS
WILL DEVELOP ALONG AND/OR AHEAD OF THE SURFACE BOUNDARY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...DLF
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
639 PM CDT TUE JUL 30 2013
...UPDATE TO ADD UPDATE SECTION AND 00Z AVIATION DISCUSSION...
.UPDATE...
ISSUED AT 630 PM CDT TUE JUL 30 2013
HAVE A CONCERN THROUGH THE OVERNIGHT HOURS FOR DENSE FOG. WET GROUNDS
FROM ANTECEDENT RAINS AND CALM WINDS WILL CREATE AN ENVIRONMENT THAT
IS CONDUCIVE FOR DENSE FOG. THIS IS SUGGESTED WITH HRRR AND BUFKIT GUIDANCE
AS WELL AS SOME MOS GUIDANCE. AS A RESULT, HAVE ISSUED A DENSE FOG ADVISORY.
SECOND CONCERN WAS TO REMOVE ANY STORM CHANCES THIS EVENING AS ACTIVITY
IS NORTHWEST KANSAS IS WEAKENING AND CUMULUS ACROSS THE KANSAS/COLORADO
BORDER IS NOT UNDERGOING ADEQUATE VERTICAL GROWTH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 156 PM CDT TUE JUL 30 2013
TODAY IS SEEING A VERY SLOW CLEARING PATTERN IN THE CLOUDS FROM
WEST TO EAST. THIS SLOWNESS IN CLEARING IS PARTIALLY DUE TO THE
NORTH TO NORTHEAST LOW LEVEL FLOW, WHICH IS A SLIGHT UPSLOPE
PATTERN. THE OTHER REASON THE EAST IS SO SLOW TO CLEAR OUT IS THE
ABUNDANT SURFACE MOISTURE ACROSS OUR EASTERN ZONES, WITH PLENTY OF
LEFTOVER RAINFALL STILL ACROSS MUCH OF THE EASTERN FORECAST AREA,
ESPECIALLY SOUTHEAST OF A LINE FROM LA CROSSE TO ASHLAND. SOME OF
THESE COUNTIES RECEIVED OVER 3 INCHES OF RAINFALL MONDAY EVENING,
ESPECIALLY ACROSS PRATT AND BARBER COUNTIES. FOR THIS REASON, ALONG
WITH EXPECTED CLEAR SKIES AND LIGHT WINDS EXPECTED, THERE SHOULD
BE SOME MORE FOG FORM TOWARD 09Z TO 10Z. I HAVE DECIDED TO PUT IN
PATCHY FOG WORDING FOR NOW ACROSS OUR SOUTHEASTERN SECTIONS, AND
LATER SHIFTS CAN UPDATE TO DENSE FOG IF IT FORMS. BOTH THE NAM
AND THE HRRR MODELS ARE INDICATED AROUND 1SM VISIBILITIES IN FOG.
AS FOR LOW TEMPERATURES, NO CHANGES WERE MADE TO THE PREVIOUS
FORECAST. CLEAR SKIES AND LIGHT WINDS WILL ALLOW TEMPERATURES TO
DROP TO THE MID 60S IN OUR WEST AND THE UPPER 60S IN OUR
SOUTHEAST.
MOSTLY SUNNY SKIES AREA EXPECTED WEDNESDAY, AFTER SOME SCATTERED
MORNING FOG. WINDS WILL BE LIGHT AND VARIABLE EARLY, THEN SHIFT TO
THE SOUTHEAST IN THE AFTERNOON AT 10 TO 20 MPH. A COLD FRONT
WILL APPROACH WESTERN KANSAS BY AFTERNOON. THE NAM MODEL BRINGS IN
THUNDERSTORMS WEDNESDAY AFTERNOON AS EARLY AS 19Z IN OUR NORTHWEST
ZONES OF SCOTT AND LANE COUNTIES, AND ADVANCES THE RAIN TOWARD
DODGE CITY AS EARLY AS 22Z. THE ECMWF AND GFS MODELS ARE A LITTLE
SLOWER, BRINGING RAIN TO SCOTT AND LANE COUNTIES AFTER 22Z AND NOT
NEAR DODGE CITY UNTIL AFTER 02Z. HAVE STARTED SLIGHT 20 PERCENT
CHANCES IN OUR FAR NORTHWEST, SUCH AS SCOTT AND LANE COUNTIES, AND
DELAYED THE ONSET OF CHANCE POP CATEGORIES IN THE DODGE CITY AREA
UNTIL 03Z. SOME OF THE LATE AFTERNOON AND EVENING STORMS COULD
CONTAIN DAMAGING WINDS AND HAIL AS LARGE AS GOLF BALLS. THE FRONT
WILL MOVE THROUGH WESTERN AND INTO CENTRAL KANSAS BY WEDNESDAY
EVENING, BRINGING RAIN CHANCES FOR SHOWERS AND THUNDERSTORMS TO
THE PRATT AND COLDWATER AREAS AFTER 00Z THURSDAY. WITH SKIES
STARTING OUT WEDNESDAY MORNING AS MOSTLY SUNNY, THEN BECOMING
PARTLY CLOUDY BY MID TO LATE AFTERNOON, AND POSSIBLY EVEN MOSTLY
CLOUDY BY EVENING, MAXIMUM TEMPERATURES COULD BE A LITTLE TRICKY.
STAYED WITH THE PREVIOUS FORECAST OF MID 90S IN THE WEST AND NEAR
90F IN THE EAST. HOW MUCH RAIN WILL FALL IS ALWAYS A LITTLE
CHALLENGING, BUT I THINK THE QPF_FM_POP PROCEDURE DID A FAIRLY
GOOD JOB WITH FORECAST RAINFALL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 339 PM CDT TUE JUL 30 2013
AN UPPER LEVEL LONGWAVE TROUGH WILL GENERALLY RESIDE OVER THE EASTERN
UNITED STATES THROUGH TUESDAY AUGUST 6TH, WITH UPPER LEVEL RIDGING
WAFFLING BACK AND FORTH BETWEEN NEW MEXICO AND TEXAS. ALONG THE
NORTHERN PERIPHERY OF THE RIDGE OVER THE CENTRAL HIGH PLAINS, A
QUASI-STATIONARY SURFACE FRONTAL BOUNDARY WILL EXIST, WITH LOW
LEVEL MOISTURE CONVERGING ALONG AND NORTH OF THE BOUNDARY.
ADDITIONALLY, EVAPOTRANSPIRATION FROM THE PREVIOUS HEAVY RAINS
ACROSS THE SOUTHERN AND CENTRAL PLAINS AND SUBSEQUENT TRANSPORT OF
THIS MOISTURE TO THE NORTHWEST WITH THE LOW LEVEL FLOW, WILL
ENHANCE MIXING RATIOS EVEN FURTHER. CONVECTIVE CLUSTERS WILL
ORIGINATE OFF OF THE VARIOUS TERRAIN FEATURES IN THE LEE OF THE
ROCKIES JUST ABOUT EVERY DAY, AND A FEW OF THESE COULD GROW
UPSCALE INTO LARGER CONVECTIVE CLUSTERS AND AFFECT WESTERN KANSAS
THROUGH AUGUST 6TH. THE TIMING OF THE INDIVIDUAL STORM CLUSTERS
CANNOT BE PREDICTED WITH MUCH ACCURACY IN THIS REGIME. THEREFORE,
20 TO 40% STORM CHANCES WERE GENERALLY MAINTAINED THROUGH AUGUST
6TH. ALSO, GIVEN THE UNCERTAINTY IN ANY CONVECTION AND RESULTANT
COOL OUTFLOW, HIGH TEMPERATURES WILL BE TRICKY AS WELL. OUR BEST
ESTIMATE IS THAT HIGH AND LOW TEMPERATURES WILL BE WITHIN A FEW
DEGREES OF CLIMATOLOGICAL VALUES (HIGHS 86-97F AT DODGE CITY, WITH
COOLER READINGS THAN THIS NEAR INTERSTATE 70 AND WARMER READINGS
NEAR THE OKLAHOMA STATE LINE). KEEP IN MIND THAT ANY WIDESPREAD
CLOUD COVER OR RAINFALL COULD LEAD TO MUCH COOLER TEMPERATURES ON
ANY GIVEN DAY.
AFTER AUGUST 6TH, THE VARIOUS MODELS ARE ADVERTISING A STRONG UPPER
LEVEL LOW TO DROP SOUTHWARD OUT OF CANADA INTO THE GREAT LAKES
REGION. THE ASSOCIATED COLD FRONT COULD BRING MUCH COOLER AIR INTO THE
CENTRAL PLAINS BY LATE NEXT WEEK, WITH HIGHS POSSIBLY FALLING INTO
THE 70S DEPENDING ON THE AMOUNT OF ACCOMPANYING CLOUD COVER AND
PRECIPITATION BEHIND THE FRONT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 630 PM CDT TUE JUL 30 2013
IFR/LIFR CIGS POSSIBLE ACROSS EASTERN SECTIONS...MAINLY IMPACTING KDDC
AND PARTICULARLY KHYS DUE TO FOG FORMATION THROUGH THE OVERNIGHT AND
INTO THE MORNING HOURS. WINDS WILL BE CALM THROUGH MORNING AND THEN
SOUTHERLY 5-11 KT TOMORROW AFTER 15Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 66 93 68 93 / 10 30 30 30
GCK 66 94 68 94 / 10 40 40 30
EHA 67 95 67 95 / 10 30 40 30
LBL 68 95 69 95 / 10 30 40 30
HYS 65 89 68 92 / 10 30 30 40
P28 69 89 70 94 / 0 10 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY FROM 1 AM TO 9 AM CDT WEDNESDAY FOR KSZ031-
046-065-066-079>081-089-090.
&&
$$
UPDATE...SUGDEN
SHORT TERM...BURKE
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
537 PM MDT TUE JUL 30 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 PM MDT TUE JUL 30 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS ELONGATED RIDGE ACROSS
THE SOUTHERN PLAINS WITH WESTERLY FLOW IN PLACE ACROSS THE
CENTRAL/HIGH PLAINS. A WEAK LEE TROUGH IS CURRENTLY IN PLACE ACROSS
EASTERN COLORADO WITH A WEAK CONVERGENCE REGION EXTENDING INTO OUR
WESTERN CWA.
THIS WILL ACT AS THE FOCUS FOR ISOLATED THUNDERSTORM DEVELOPMENT
THIS AFTERNOON...WITH CU FIELD ALREADY IN PLACE AND RADAR INDICATING
SEVERAL DEVELOPING UPDRAFTS JUST NW OF OUR CWA NEAR YUMA COUNTY. WITH
STORM MOTIONS OUT OF THE EAST 10-20KT MOST STORMS WILL BE SLOW
MOVERS...THOUGH WE COULD STILL SEE THIS ACTIVITY MOVE FURTHER EAST
IN OUR CWA THROUGH THE AFTERNOON BEFORE FALLING APART AFTER SUNSET
WITH LOSS OF DAYTIME HEATING AND INCREASING LOW LEVEL CINH. LATEST
RAP ANALYSIS SHOWS SB/ML CAPE VALUES RANGING FROM 1000-1500
J/KG...AND WITH ADJUSTED SOUNDINGS SUPPORTING POSSIBLE CAPE VALUES
IN THE 2000-2500J/KG RANGE LATER THIS AFTERNOON. WITH HIGH TD
DEPRESSIONS TO ABOUT 700MB THROUGH A DRY ADIABATIC AIR MASS AND HIGH
LFC/LCL IN THE 10-13KFT RANGE WE COULD SEE STRONG THUNDERSTORM GUST
POTENTIAL. IF WE REALIZE THE HIGHER CAPE VALUES I COULDNT RULE OUT
LARGE HAIL POTENTIAL...HOWEVER AT THIS POINT STRONG WINDS ARE
PROBABLY THE GREATER THREAT WITH ANY THUNDERSTORMS THAT DEVELOP.
MET/MAV GUIDANCE ARE INDICATING FOG DEVELOPMENT TONIGHT...HOWEVER
WITH W-SW WINDS TO 10KT AT THE SURFACE AND BL WINDS IN EXCESS OF
20KT...I AM NOT AS CONFIDENT WE WILL SEE A REPEAT OF LAST NIGHT.
WITH TROUGH AXIS SHIFTING EAST WE COULD STILL SEE LIGHT SURFACE
WINDS IN THE EAST WHERE FOG WOULD BE MORE LIKELY TO OCCUR...AND
WHERE I KEPT PATCHY FOG MENTION.
A WEAK COLD FRONT WILL DROP SOUTH LATE TONIGHT AND STALL ALONG THE
NE/KS STATE LINE BY MIDDAY WEDNESDAY WITH A PRE FRONTAL TROUGH
SETTLING TO OUR SOUTHEAST. AHEAD OF THE TROUGH AXIS CAPE VALUES IN
EXCESS OF 2500 J/KG ARE ADVERTISED. THIS TROUGH AXIS WILL BE THE
MAIN FOCUS WITH GOOD SURFACE CONVERGENCE IN PLACE...AND I KEPT 30/40
POPS TIED TO THIS FEATURE...AND LOWER POPS TO THE NORTH. WITH BETTER
CAPE AND MARGINALLY BETTER SHEER WE WILL SEE A CHANCE FOR
THUNDERSTORMS TO BECOME BETTER ORGANIZED WITH SEVERE WIND/HAIL A
POSSIBILITY IN OUR SOUTHEAST DURING THE AFTERNOON.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 250 PM MDT TUE JUL 30 2013
NO MAJOR CHANGES SEEN TO THE UPPER PATTERN ACROSS THE SOUTHERN AND
CENTRAL PLAINS DURING THIS PERIOD. UPPER HIGH NOW CENTERED OVER
NEW MEXICO AND WAFFLE BACK AND FORTH OVER TO WEST TEXAS AND BACK DURING
PERIOD. ALTHOUGH THE UPPER RIDGE IS FORECAST TO ASSERT ITSELF SLIGHTLY
NORTH OVER THE MOUNTAINS...A SERIES OF WEAK UPPER IMPULSES WILL
CONTINUE TO MOVE OVER THE TOP OF THE RIDGE KEEPING IT FAIRLY
FLAT OVERALL.
THIS MAKES IT DIFFICULT TO ASSESS TIMING OF PRECIPITATION. ALL
GUIDANCE IS SUGGESTING AN ACTIVE FLOW REGIME WILL CONTINUE WITH
SLIGHT CHANCE TO CHANCE POPS EVERY DAY. RIGHT NOW THE MOST ACTIVE
PERIODS FOR PRECIPITATION LOOK TO BE THURSDAY NIGHT AND AGAIN
SATURDAY NIGHT. TEMPERATURES WILL CONTINUE SEASONAL WITH HIGHS
MOSTLY IN THE UPPER 80S TO LOWER 90S AND LOWS IN THE 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 531 PM MDT TUE JUL 30 2013
VFR TO POSSIBLY MVFR CONDITIONS ARE FORECAST FOR THE 0Z TAFS.
WINDS AT KGLD WILL SLOWLY SHIFT TO THE SOUTHEAST OVER THE NEXT
FEW HOURS AS THE DECAYING THUNDERSTORM SOUTHEAST OF KGLD CONTINUES
TO MOVE AWAY. OVERNIGHT KMCK MAY HAVE SOME PATCHY FOG AND LOW
CLOUDS. WEDNESDAY A WEAK FRONT/SURFACE TROUGH WILL MOVE INTO THE
AREA DURING THE MORNING. THE LIGHT WINDS WILL SHIFT TO THE NORTH
BEHIND THE SURFACE BOUNDARY. DURING THE AFTERNOON THUNDERSTORMS
WILL DEVELOP ALONG AND/OR AHEAD OF THE SURFACE BOUNDARY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...DLF
AVIATION...JTL
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1045 PM EDT TUE JUL 30 2013
.UPDATE...
ISSUED AT 1045 PM EDT TUE JUL 30 2013
DID A QUICK UPDATE TO THE GRIDS AND ZONES TO FINE TUNE RAIN CHANCES
THROUGH THE NIGHT AS WELL AS TO PUSH BACK ANY THUNDER CHANCES UNTIL
CLOSER TOWARDS DAWN...FOR MOST LOCATIONS. ALSO TWEAKED TEMPS AND
DEWPOINTS PER THE LATEST OBS AND TRENDS. UPDATES HAVE BEEN SENT TO
THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 645 PM EDT TUE JUL 30 2013
22Z SFC ANALYSIS SHOWS THAT OUR COOL HIGH PRESSURE IS NOW RETREATING
TO THE EAST IN THE FACE OF A DEVELOPING AREA OF LOW PRESSURE LIFTING
INTO THE MID MISSISSIPPI VALLEY. AHEAD OF THIS LOW...AN MCV IN THE
MID LEVELS OF THE ATMOSPHERE IS PUSHING EAST INTO KENTUCKY THIS
EVENING. THIS IS HELPING TO SUSTAIN A LARGE AREA OF LIGHT TO MODERATE
RAIN SLOWLY CROSSING THE BLUEGRASS STATE. FOR EAST KENTUCKY...SO
FAR...THIS HAS MEANT LITTLE MORE THAN SOME VIRGA OVER THE CUMBERLAND
VALLEY BUT MORE SUBSTANTIAL SHOWERS ARE NOT FAR OUT. EXPECT THE RAIN
TO OVERTAKE THE CWA THROUGH THE LATE EVENING AND EARLY MORNING HOURS
FROM WEST TO EAST. A STRAY BOLT OF LIGHTNING WILL BE POSSIBLE THROUGH
THE NIGHT ALONG WITH HEAVIER AMOUNTS OF RAIN FOR THE SOUTHEAST PARTS
OF THE AREA PER THE LATEST NAM12 AND HRRR GUIDANCE. HAVE UPDATED THE
FIRST TWO PERIODS OF THE FORECAST TO REFLECT THIS. ALSO ADJUSTED
TEMPERATURES AND DEWPOINTS THROUGH THE NIGHT IN LINE WITH THE LATEST
THOUGHTS ON PCPN CHANCES AND QPF. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS...ALONG WITH A FRESHENED SET OF ZONES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 250 PM EDT TUE JUL 30 2013
SFC WARM FRONT FROM SRN ILL TO MIDDLE TENN AND SLOWLY CREEPING TO THE
NE. CURRENT PCPN APPEARS TO BE EDGING INTO MIDDLE KY. CURRENT CLOUD
COVER OVER ERN KY IS HIGH CI WITH SOME MID LEVEL CLOUDS AND VIRGA
EDGING INTO OUR SWRN COUNTIES. SKEW-T INDICATES A WEAK SPEED MAX AT
50H COINCIDENT WITH A VERY MOIST LAYER ABOVE AND VERY DRY BELOW THAT
MAX. SHOULD SEE A GRADUAL MOISTENING OF THE LOWER LAYERS AND A
LOWERING OF THE CEILING HEIGHTS THIS EVENING INTO TONIGHT.
MODELS INDICATE THE PCPN ENTERING THE I-75 CORRIDOR AROUND MIDNIGHT
TONIGHT AS A COLD FRONT SWEEPS ACROSS THE OHIO VALLEY OVERNIGHT. THE
COLD FRONT WILL PROVIDE THE BEST RAINFALL EARLY THU BEFORE BECOMING
NEARLY STATIONARY JUST EAST OF THE APPALACHIAN MTNS WITH SEVERAL
SHORT WAVES DROPPING FROM THE GREAT LAKES TO REINFORCE THE ERN TROF.
EACH SHORT WAVE WILL BRING ANOTHER QUICK SHOT OF PCPN BUT THE
RAINFALL ON WED NITE AND THU WILL NOT BE AS HEAVY OR WIDESPREAD WITH
THE FRONTAL BNDRY HAVING WRUNG MUCH OF THE AVAILABLE MOISTURE FROM
THE AIR. THE LAST OF THE SHRA SHOULD EASE OUT OF THE STATE ON THU
MORNING WITH THE SKY BEGINNING TO CLEAR THU AFTERNOON.
CLOUD COVER AND AN INCREASE IN DEW POINTS WILL HOLD TEMPS TONIGHT IN
THE LOWER 60S. WITH THE INFLUX OF RAIN ON WED BEFORE DROPPING TO THE
MID 60S WED NITE. THEN WITH AN END TO THE RAIN AND SOME HELP FROM
BREAKS IN THE CLOUD COVER ON THU AFTERNOON...TEMPS COULD SHOOT UP TO
THE LOWER 80S. THU HIGHS ARE PREDICATED ON SOME CLEARING...SO IF THE
CLOUDS REMAIN THE HIGHS WILL NECESSARILY NEED TO BE LOWERED SOME.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 251 PM EDT TUE JUL 30 2013
THE MODELS START OFF IN VERY GOOD AGREEMENT WITH UPPER TROUGHS OVER
BOTH COASTS AND AN UPPER RIDGE OVER THE ROCKIES. WITH THIS TYPE OF
PATTERN...SYSTEMS FROM THE WEST COAST ARE BEING BLOCKED BY THE RIDGE
FROM MOVING ACROSS THE AREA. ALL THE SYSTEMS THAT COME THROUGH THE
AREA COME FROM ARES FAR TO THE NORTH AND THEN MOVE DOWN THE BACK OF
THE UPPER TROUGH. THIS SHOULD RESULT IN CONTINUED COOL WEATHER FOR
THIS TIME OF YEAR. BY SUNDAY...THE TIMING OF THE SYSTEMS STARTS TO
BECOME LESS CERTAIN AS THE MODELS DIFFER IN THE TIMING OF THE SHORT
WAVES MOVING DOWN THE BACK SIDE OF THE TROUGH. THE GFS HAS A FRONT
MOVING THROUGH THE AREA ON SATURDAY AND HAS THE LAST OF THE
PRECIPITATION MOVING OUT OF THE AREA SUNDAY MORNING. THE 00Z ECMWF
IS A LITTLE SLOWER WITH MOVING THE RAIN OUT. THE GFS BRINGS THE NEXT
SYSTEM THROUGH ON TUESDAY WHILE THE THE 00Z ECMWF THEN DOES NOT MOVE
THE NEXT SYSTEM INTO THE AREA UNTIL WEDNESDAY. WILL STAY WITH A
MODEL BLEND FOR TIMING AND THEN NUDGE IT TOWARD THE NEW ECMWF
FORECAST WHEN IT COMES IN AT 3 PM. FOR TEMPERATURES STAYED CLOSE
STAYED A BIT COOLER THAN MOS...BUT DID NOT MAKE ANY LARGE CHANGES
FROM THE CONSENSUS MODEL BLEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 835 PM EDT TUE JUL 30 2013
AVIATION CONDITIONS WILL GRADUALLY WORSEN THROUGHOUT THE FORECAST
AREA OVERNIGHT AS A LARGE AREA OF SHOWERS MOVES IN FROM THE WEST.
THIS WILL LOWER VIS AND CIGS IN THE SOUTHWEST LOCATIONS THIS EVENING
BEFORE OVERTAKING THE REST OF THE AREA LATER TONIGHT. DURING THE
WORST OF IT...AN EXTENDED PERIOD MVFR CAN BE EXPECTED WITH
INTERMITTENT TIMES OF IFR. THUNDERSTORMS WILL BE POSSIBLE LATER
TONIGHT AS WELL WITH THE BEST CHANCES OCCURRING ON WEDNESDAY. THE
PCPN THREAT SHOULD COME TO AN END FROM WEST TO EAST DURING THE LATTER
PART OF THE DAY...WEDNESDAY. WINDS WILL BE RELATIVELY LIGHT THROUGH
THE PERIOD...GRADUALLY SWITCHING FROM THE SOUTHEAST TO WEST BY MID
DAY WEDNESDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...DUSTY
LONG TERM...JJ
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
923 PM EDT TUE JUL 30 2013
.FORECAST UPDATE...
Issued at 922 PM EDT Tue Jul 30 2013
Made some substantial changes to the ongoing forecast this evening,
to account for the latest trends in observations and guidance.
Current radar depicts batch of moderate rainfall now pushing east of
the I-65 corridor. This rain is in association with a slug of
isentropic ascent pushing northeast ahead of an approaching
shortwave trough. Behind this steadier rain, scattered showers
continue across western KY. The main question will be if coverage
of these showers increase over the next few hours as the main
shortwave trough approaches, or whether they continue as scattered
and light in nature. The latest guidance suggests that the main QG
forcing associated with the approaching trough will stay mainly
across far southern KY and TN. The latest HRRR supports this
thinking, moving this initial slug of precipitation out and keeping
just scattered showers around for the rest of the night, with the
heavier showers/embedded storms across southern KY and TN. Will
trend the forecast drier, however, do still expect at least some
expansion in the precip overnight across KY as the main shortwave
trough approaches. Therefore, after an initial decrease in pops
late this evening across the west, will keep pops at around 50 after
midnight for most locations, with higher amounts towards morning
across the Cumberland region where it looks like the best forcing
for ascent will reside. Updated products already out.
Issued at 611 PM EDT Tue Jul 30 2013
Ran an update early this evening to account for the latest
precipitation trends. Light to moderate showers continue to push
east towards the I-65 corridor. Rainfall rates/amounts with this
activity have been rather meager, with many locations picking up
less than a tenth of an inch per hour with this activity. Debated
removing thunder potential for tonight, but as the shortwave trough
approaches, a low-level jet should develop in response. An
inversion around 850mb will lead to some weak elevated instability,
so the forced ascent along the nose of the LLJ could lead to
isolated rumbles of thunder. The best chance for this looks to be
across southern KY. Otherwise, the rest of the forecast looks on
track.
&&
.SHORT TERM (Tonight through Wednesday night)...
Issued at 310 PM EDT Tue Jul 30 2013
Expect unsettled weather over the next 24-36 hours, as a couple of
upper-level disturbances interact with a nearly stationary front
across the Ohio and Tennessee Valleys. Main impact will be a soaking
rain overnight into Wednesday morning.
This afternoon we can see an unusually solid precip shield for this
time of year moving into western Kentucky and southwest Indiana, as
a disturbance in the zonal upper flow pushes across the Mississippi
Valley. Expect this activity to continue to spread eastward across
central KY and southern IN during the late afternoon and early
evening. Heaviest precip will be after midnight tonight and into
Wednesday morning. Nearly moist adiabatic profiles will leave us
hard pressed for thunder, let alone severe. PWATs near 2 inches and
potential long duration of precip could support heavy rainfall, but
that is tempered somewhat by not-so-vigorous upward motion. Total
QPF will be an inch to maybe an inch and a half, most likely just a
soaking rain for much of the area.
By Wednesday afternoon some drier air will begin to sweep in aloft,
and may contribute to some gusty winds with some of the stronger
cells. The best chance for any strong wind gust will be in the
southeast, toward Lake Cumberland.
Temps will be modulated by clouds and precip. Still quite a bit of
room to drop tonight, so we should be in the upper 60s in most
locations. Max temps on Wednesday are near consensus of raw model
data, and split the difference neatly between GFS MOS and NAM MOS,
just either side of 80.
Precip chances will drop rapidly Wednesday evening, with slight or
low chance POPs limited to areas east of I-65 after midnight. Drier
air will take a while to arrive, so it will be the warmest and
muggiest night of the week, but still only around climo.
.LONG TERM (Thursday through Tuesday)...
Issued at 307 PM EDT Tue Jul 30 2013
This forecast period is anticipated to be rather unsettled in the
Ohio Valley as a series of shortwaves traverses through. Long range
models indicate a persistent pattern of troughing over southern
Canada and ridging over the southwest U.S. Analysis of NCEP`s
ensembles unveils the region locked into slightly anomalous (below
normal) 850mb mean temps for the entire period along with decent
precip chances on Thursday as well as another good shot Saturday.
The latest run of the GFS (12Z) finally agrees with this assessment
through the weekend, attempting to line up more with the 00Z run of
the ECMWF.
Given the significant deterministic model divergence starting
Monday, have kept PoPs at just slight chance through the early work
week for now until higher confidence can be applied to the forecast.
Am tempted to lean more toward the ECMWF (00Z is the latest provided
at this time) for early next week given that the GFS seems to push
the stubborn Canadian trough off into the Atlantic a little too
quickly. The GFS opening up the pattern locally for a low to eject
into the Great Lakes region from the northern Plains and am thinking
it`ll be a more progressive pattern shift rather than the abruptness
it paints. Do agree with the GFS depicting a boundary slowing down
and eventually washing out as it struggles to make its way into the
Southeast by the middle of next week but considering the low
confidence for the beginning of the week and given that this begins
to reach beyond the scope of this forecast, will simply have to take
the wait and see approach for now to see the overall evolution.
As alluded to already, temps should remain slightly below normal for
this time of year and have gone with highs primarily in the low to
mid 80s. Lows could be a bit closer to normal and should range from
the low to mid 60s overnight Thursday and moderating to around the
70 degree mark by early next week. Nailing down the specifics of
temps is typically tricky in the long term period but is especially
difficult since cloud cover/precip could vastly change just how high
or low temps will get as well as the confidence of said weather
being relatively low, as aforementioned.
&&
.AVIATION (00Z TAF Update)...
Issued at 723 PM EDT Tue Jul 30 2013
This TAF period will be characterized by a rather complex weather
setup, lending to rather low confidence in just how things will play
out overnight into tomorrow. In the near term, light to moderate
showers will continue to spread east across all TAF sites. Some
pockets of heavier rain will be capable of briefly dropping
conditions into MVFR thresholds (as SDF experienced earlier in the
evening), but the next few hours should remain mostly VFR across all
sites.
Confidence begins to decrease overnight, as the next shortwave
trough approaches the region. The latest guidance suggests that the
main forcing with this system may scoot mainly south of KLEX and
KSDF, which would bring much less precip early Wednesday morning
throughout the day. Therefore, have backed off a bit on the
prevailing rainfall at these sites. Cigs/vsbys may still drop into
MVFR thresholds, with perhaps even some pockets of IFR cigs possible
as some cooler air works in behind the system Wednesday morning.
However, am not confident enough in that scenario at this time, thus
will leave MVFR cigs of FL022-FL025 at all sites. Have removed VCTS
at KSDF and KLEX given the above reasoning, but left it at KBWG
where it looks like a bit more instability may be present.
Otherwise, winds will be rather light and out of the south
throughout the period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........KD
Short Term.......RAS
Long Term........lg
Aviation.........KD
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
835 PM EDT TUE JUL 30 2013
.UPDATE...
ISSUED AT 645 PM EDT TUE JUL 30 2013
22Z SFC ANALYSIS SHOWS THAT OUR COOL HIGH PRESSURE IS NOW RETREATING
TO THE EAST IN THE FACE OF A DEVELOPING AREA OF LOW PRESSURE LIFTING
INTO THE MID MISSISSIPPI VALLEY. AHEAD OF THIS LOW...AN MCV IN THE
MID LEVELS OF THE ATMOSPHERE IS PUSHING EAST INTO KENTUCKY THIS
EVENING. THIS IS HELPING TO SUSTAIN A LARGE AREA OF LIGHT TO MODERATE
RAIN SLOWLY CROSSING THE BLUEGRASS STATE. FOR EAST KENTUCKY...SO
FAR...THIS HAS MEANT LITTLE MORE THAN SOME VIRGA OVER THE CUMBERLAND
VALLEY BUT MORE SUBSTANTIAL SHOWERS ARE NOT FAR OUT. EXPECT THE RAIN
TO OVERTAKE THE CWA THROUGH THE LATE EVENING AND EARLY MORNING HOURS
FROM WEST TO EAST. A STRAY BOLT OF LIGHTNING WILL BE POSSIBLE THROUGH
THE NIGHT ALONG WITH HEAVIER AMOUNTS OF RAIN FOR THE SOUTHEAST PARTS
OF THE AREA PER THE LATEST NAM12 AND HRRR GUIDANCE. HAVE UPDATED THE
FIRST TWO PERIODS OF THE FORECAST TO REFLECT THIS. ALSO ADJUSTED
TEMPERATURES AND DEWPOINTS THROUGH THE NIGHT IN LINE WITH THE LATEST
THOUGHTS ON PCPN CHANCES AND QPF. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS...ALONG WITH A FRESHENED SET OF ZONES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 250 PM EDT TUE JUL 30 2013
SFC WARM FRONT FROM SRN ILL TO MIDDLE TENN AND SLOWLY CREEPING TO THE
NE. CURRENT PCPN APPEARS TO BE EDGING INTO MIDDLE KY. CURRENT CLOUD
COVER OVER ERN KY IS HIGH CI WITH SOME MID LEVEL CLOUDS AND VIRGA
EDGING INTO OUR SWRN COUNTIES. SKEW-T INDICATES A WEAK SPEED MAX AT
50H COINCIDENT WITH A VERY MOIST LAYER ABOVE AND VERY DRY BELOW THAT
MAX. SHOULD SEE A GRADUAL MOISTENING OF THE LOWER LAYERS AND A
LOWERING OF THE CEILING HEIGHTS THIS EVENING INTO TONIGHT.
MODELS INDICATE THE PCPN ENTERING THE I-75 CORRIDOR AROUND MIDNIGHT
TONIGHT AS A COLD FRONT SWEEPS ACROSS THE OHIO VALLEY OVERNIGHT. THE
COLD FRONT WILL PROVIDE THE BEST RAINFALL EARLY THU BEFORE BECOMING
NEARLY STATIONARY JUST EAST OF THE APPALACHIAN MTNS WITH SEVERAL
SHORT WAVES DROPPING FROM THE GREAT LAKES TO REINFORCE THE ERN TROF.
EACH SHORT WAVE WILL BRING ANOTHER QUICK SHOT OF PCPN BUT THE
RAINFALL ON WED NITE AND THU WILL NOT BE AS HEAVY OR WIDESPREAD WITH
THE FRONTAL BNDRY HAVING WRUNG MUCH OF THE AVAILABLE MOISTURE FROM
THE AIR. THE LAST OF THE SHRA SHOULD EASE OUT OF THE STATE ON THU
MORNING WITH THE SKY BEGINNING TO CLEAR THU AFTERNOON.
CLOUD COVER AND AN INCREASE IN DEW POINTS WILL HOLD TEMPS TONIGHT IN
THE LOWER 60S. WITH THE INFLUX OF RAIN ON WED BEFORE DROPPING TO THE
MID 60S WED NITE. THEN WITH AN END TO THE RAIN AND SOME HELP FROM
BREAKS IN THE CLOUD COVER ON THU AFTERNOON...TEMPS COULD SHOOT UP TO
THE LOWER 80S. THU HIGHS ARE PREDICATED ON SOME CLEARING...SO IF THE
CLOUDS REMAIN THE HIGHS WILL NECESSARILY NEED TO BE LOWERED SOME.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 251 PM EDT TUE JUL 30 2013
THE MODELS START OFF IN VERY GOOD AGREEMENT WITH UPPER TROUGHS OVER
BOTH COASTS AND AN UPPER RIDGE OVER THE ROCKIES. WITH THIS TYPE OF
PATTERN...SYSTEMS FROM THE WEST COAST ARE BEING BLOCKED BY THE RIDGE
FROM MOVING ACROSS THE AREA. ALL THE SYSTEMS THAT COME THROUGH THE
AREA COME FROM ARES FAR TO THE NORTH AND THEN MOVE DOWN THE BACK OF
THE UPPER TROUGH. THIS SHOULD RESULT IN CONTINUED COOL WEATHER FOR
THIS TIME OF YEAR. BY SUNDAY...THE TIMING OF THE SYSTEMS STARTS TO
BECOME LESS CERTAIN AS THE MODELS DIFFER IN THE TIMING OF THE SHORT
WAVES MOVING DOWN THE BACK SIDE OF THE TROUGH. THE GFS HAS A FRONT
MOVING THROUGH THE AREA ON SATURDAY AND HAS THE LAST OF THE
PRECIPITATION MOVING OUT OF THE AREA SUNDAY MORNING. THE 00Z ECMWF
IS A LITTLE SLOWER WITH MOVING THE RAIN OUT. THE GFS BRINGS THE NEXT
SYSTEM THROUGH ON TUESDAY WHILE THE THE 00Z ECMWF THEN DOES NOT MOVE
THE NEXT SYSTEM INTO THE AREA UNTIL WEDNESDAY. WILL STAY WITH A
MODEL BLEND FOR TIMING AND THEN NUDGE IT TOWARD THE NEW ECMWF
FORECAST WHEN IT COMES IN AT 3 PM. FOR TEMPERATURES STAYED CLOSE
STAYED A BIT COOLER THAN MOS...BUT DID NOT MAKE ANY LARGE CHANGES
FROM THE CONSENSUS MODEL BLEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 835 PM EDT TUE JUL 30 2013
AVIATION CONDITIONS WILL GRADUALLY WORSEN THROUGHOUT THE FORECAST
AREA OVERNIGHT AS A LARGE AREA OF SHOWERS MOVES IN FROM THE WEST.
THIS WILL LOWER VIS AND CIGS IN THE SOUTHWEST LOCATIONS THIS EVENING
BEFORE OVERTAKING THE REST OF THE AREA LATER TONIGHT. DURING THE
WORST OF IT...AN EXTENDED PERIOD MVFR CAN BE EXPECTED WITH
INTERMITTENT TIMES OF IFR. THUNDERSTORMS WILL BE POSSIBLE LATER
TONIGHT AS WELL WITH THE BEST CHANCES OCCURRING ON WEDNESDAY. THE
PCPN THREAT SHOULD COME TO AN END FROM WEST TO EAST DURING THE LATTER
PART OF THE DAY...WEDNESDAY. WINDS WILL BE RELATIVELY LIGHT THROUGH
THE PERIOD...GRADUALLY SWITCHING FROM THE SOUTHEAST TO WEST BY MID
DAY WEDNESDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...DUSTY
LONG TERM...JJ
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS GRAY ME
102 PM EDT MON JUL 29 2013
.SYNOPSIS...
LOW PRESSURE NEAR HUDSON BAY WILL DRAG A TRAILING COLD FRONT ACROSS
THE AREA LATE THIS AFTERNOON...THEN OFFSHORE TONIGHT. AN UPPER LOW WILL
CROSS NORTH OF THE REGION TUESDAY. A WEAK RIDGE OF HIGH PRESSURE
WILL BRING A PLEASANT DAY WITH SUNNY SKIES FOR WEDNESDAY. A SERIES
OF DISTURBANCES WILL CROSS THE REGION THURSDAY THROUGH SUNDAY
BRINGING SCATTERED SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1259 PM...CONVECTION FIRING FROM THE UPPER CONNECTICUT RIVER
VALLEY NORTHEASTWARD INTO FAR NORTHERN OXFORD COUNTY MAINE. HAVE
UPDATED THE FORECAST TO ACCOUNT FOR THIS AS RAP MODEL IS HANDLING
THE CURRENT TRENDS FAIRLY WELL. FOLLOWED A RAP/NAM MIX INTO THIS
EVENING. STORM PREDICTION CENTER STILL SHOWING A VERY SLIGHT
CHANCE OF SEVERE WEATHER IN OUR AREA THIS AFTERNOON AND EVENING.
AT THIS TIME STORMS ARE MOSTLY GOING UP AND DOWN WITHOUT INCIDENT.
939 AM...ADJUSTED MAINLY POP AND SKY COVER TO MATCH CURRENT TRENDS.
STILL BELIEVE THAT INLAND WESTERN MAINE AND NORTHERN AND CENTRAL
NEW HAMPSHIRE THIS AFTERNOON WILL BE THE FOCUS FOR ANY CONVECTION
THAT CAN GET GOING. AFTERNOON HEATING WILL BE THE KEY TO
THUNDERSTORMS OCCURRING. STORM PREDICTION CENTER HAS HIGHLIGHTED
NORTHERN NEW ENGLAND FOR A VERY LOW RISK OF SEVERE THIS AFTERNOON
-- MAINLY CONTINGENT UPON RECEIVING SUFFICIENT HEATING FOR
CONVECTION TO FIRE.
615 AM...I ADJUSTED 1ST PERIOD GRIDS BASED ON RADAR TRENDS AS WELL
AS THE 10Z MESONET FOR THIS ESTF UPDATE.
PREV DISC...
AT 06Z...A 1015 MILLIBAR LOW AND A WAVY FRONTAL BOUNDARY WERE
SITUATED ACROSS THE GULF OF MAINE. A 1011 MILLIBAR LOW WAS
CENTERED SOUTHEAST OF HUDSON BAY WITH A TRAILING COLD FRONT OVER
EASTERN NEW YORK STATE.
THE COLD FRONT WILL SLIDE EASTWARD TODAY ACCOMPANIED BY SCATTERED
SHOWERS AND THUNDERSTORMS. THE SOUTHERLY TRAJECTORY AND MARINE
INFLUENCE WILL LIMIT CONVECTION SOMEWHAT FOR THE MIDCOAST AND
ADJACENT INTERIOR. IF WE SEE SEVERAL HOURS OF CLEARING AND HEATING
TODAY...THE MODELS SUGGEST THAT A FEW STRONG STORMS ARE POSSIBLE
ACROSS EASTERN NEW HAMPSHIRE INTO WESTERN MAINE. I`VE INCLUDED
ENHANCED WORDING FOR HAIL AND GUSTY WINDS IN THE GRIDS FOR
PORTIONS OF THE FORECAST AREA LATER TODAY. HIGHS TODAY WILL RANGE
FROM NEAR 70F MIDCOAST TO THE LOWER 80S FOR SOUTHERN INTERIOR
SECTIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
THE FRONT CLEARS THE COAST TONIGHT WITH A FEW LINGERING CLOUDS
ACROSS NORTHERN SECTIONS WITH THE UPPER TROUGH ALONG WITH WIDELY
SCATTERED SHOWERS.
ON TUESDAY...MOUNTAIN CLOUDS AND SCATTERED SHOWERS WITH THE UPPER
TROUGH OTHERWISE PARTLY SUNNY WITH SEASONABLE HIGHS IN THE 70S AND
LOWER 80S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
SPOKES OF AN UPPER LEVEL TROUGH OVER CANADA AND THE EASTERN CONUS
WILL CONTINUE TO ROTATE THROUGH NORTHERN NEW ENGLAND BRINGING
PERIODS OF SHOWERS AND THUNDERSTORMS IN THE EXTENDED PERIOD.
WEDNESDAY WILL BE DRY HOWEVER AS WE WILL BE UNDER THE INFLUENCE OF
WEAK RIDGING AND IN BETWEEN TWO SHORT WAVES. TEMPERATURES INCREASE
A FEW DEGREES OVER THE PREVIOUS DAY WITH LOWER TO MID 80S ALONG
THE COAST AND SOUTH. SKIES WILL BE MOSTLY SUNNY WITH LIGHT WINDS.
SURFACE HIGH PRESSURE PASSES TO OUR SOUTH AND INTO THE EASTERN
ATLANTIC THURSDAY. INCREASING SOUTHERLY FLOW AND MORE INTENSE
TROUGHING WILL CREATE SHOWERS AND THUNDERSTORMS THURSDAY AND
FRIDAY. RAIN SHOULD START LATER THURSDAY AS A WARM FRONT LIFTS
OVER THE REGION...FOLLOWED BY A SURFACE TROUGH AXIS HELPING TO
FOCUS CONVECTION FRIDAY NIGHT. THE UPPER LEVEL TROUGH STAGNATES
WITH BLOCKING HIGH PRESSURE BUILDING OVER THE ATLANTIC. THIS WILL
KEEP NEW ENGLAND HUMID AND WARM WITH PERIODS OF SHOWERS...AS A
TRUE COLD FRONT DOESN`T ARRIVE TO USHER IN COOLER DRIER AIR UNTIL
PERHAPS NEXT MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY/...VFR CEILINGS WITH SCT MVFR IN
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. AREAS OF
MVFR TONIGHT IN FOG WITH LCL IFR CONDITIONS POSSIBLE TOWARDS DAWN
TUES IN FOG. VFR EXPECTED TUE.
LONG TERM...PERIODS OF MVFR VISIBILITIES IN FOG MOST MORNINGS.
LOWER CEILINGS IN SHOWERS THURSDAY AFTERNOON THROUGH FRIDAY NIGHT.
&&
.MARINE...
SHORT TERM /THROUGH TUESDAY/...WINDS AND SEAS WILL REMAIN BLO SCA
CONDS. LCL VSBY RESTRICTIONS IN FOG POSSIBLE THROUGH TONIGHT.
LONG TERM...WINDS AND SEAS EXPECTED TO BE BELOW SCA CRITERIA.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SHORT TERM...STJEAN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1203 PM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND THEN
CROSS THE REGION TONIGHT. ANOTHER TROUGH OF LOW PRESSURE WILL CROSS
THE REGION ON TUESDAY...FOLLOWED BY HIGH PRESSURE BUILDING ACROSS
THE REGION WEDNESDAY AND MOVING EAST THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1130 AM UPDATE: BASED ON THE LATEST RADAR IMAGERY AND HRRR MODEL
PROJECTIONS OF FUTURE EVOLUTION OF CNVCTN THIS AFTN INTO THIS
EVE...WE OPTD TO DELAY THE ONSET OF HIER POPS ASSOCIATED WITH TSTM
DEVELOPMENT TIL LATER THIS AFTN FOR MOST OF THE FA. THIS BASED ON
THE SLOWER ONSET OF ANY SUNSHINE ACROSS THE FA TO HELP INITIATE
TSTMS. LATEST HRRR MODEL RUNS SUGGEST THAT THE STRONGEST TSTMS
LATE THIS AFTN WILL BE OUT WEST WHERE THE LONGEST PD OF SUNSHINE
IS XPCTD...WITH A LN OF SCT-BKN TSTMS WEAKENING AS IT MOVES INTO
NE AND E CNTRL PTNS OF THE FA THIS EVE DUE TO LESSER SUNSHINE AND
INSTABILITY. WE WILL KEEP ENHANCED WORDING FOR GUSTY WINDS...SMALL
HAIL AND HEAVY DOWNPOURS. LASTLY...WE INCORPORATED LATEST OBSVD
TEMPS INTO THE HRLY TEMP FCST LEADING UP TO UNMODIFIED FCST HI
TEMPS THIS AFTN.
920 AM UPDATE: IN THIS UPDATE...WE ADDED ENHANCED TSTM WORDING FOR
GUSTY WINDS...SMALL HAIL AND HEAVY DOWNPOURS FOR LATER THIS AFTN
INTO THE EVE BASED ON SPC GUIDANCE...SPCLY FOR THE NW TWO THIRDS
OF THE FA. OTHER THAN INCORPORATING LATEST OBSVD TEMPS INTO THE
HRLY TEMP FCST LEADING UP TO FCST HI TEMPS THIS AFTN...NO OTHER
CHGS ATTM.
550 AM UPDATE: PATCHY SHOWERS OVER EASTERN PARTS OF THE STATE ARE
LIFTING NORTHEAST AND AWAY. RAIN WILL LIKELY END FOR A WHILE IN
THE EAST. MEANWHILE MORE CONVECTIVE SHOWERS ARE BEGINNING TO PUSH
INTO WESTERN AREAS IN RESPONSE TO THE UPPER LOW BUILDING OVER.
FORECAST WAS UPDATED TO REFLECT ONE AREA OF SHOWERS MOVING AWAY
AND THE NEXT AREA MOVING IN DURING THE COURSE OF THE DAY.
ORGNL DISC: A TROUGH OF LOW PRESSURE APPROACHING FROM THE WEST
WILL CONTINUE PULLING MOISTURE NORTH ACROSS THE AREA THIS MORNING
AS SHOWERS SPREAD IN FROM THE SOUTHWEST. SHOWERS ASSOCIATED WITH
THIS TROUGH WILL LIKELY COME IN TWO PHASES TODAY. AN INITIAL BATCH
OF SHOWERS WILL COME THROUGH THIS MORNING AS THE TROUGH DRAWS
MOISTURE NORTH ACROSS THE REGION. THERE MAY BE A BREAK AROUND
MIDDAY AS A BIT OF DRIER AIR PULLS IN ALOFT AND SKIES BRIGHTEN A
BIT. THEN LATER TODAY AS THE UPPER TROUGH MOVES IN AND HEIGHTS
LOWER THE ATMOSPHERE WILL BECOME UNSTABLE. CAPES ARE PROGGED TO
REACH AROUND 1000 J/KG LATE THIS AFTERNOON. MESOSCALE MODELS ARE
SHOWING A LINE OF SHOWERS AND THUNDERSTORMS MOVING INTO WESTERN
AREAS EARLY THIS AFTERNOON. SHOWERS AND THUNDERSTORMS WILL THEN BE
LIKELY THIS AFTERNOON ACROSS CENTRAL AND NORTHERN AREAS AS A WEAK
SURFACE TROUGH MOVES IN AND HEIGHTS CONTINUE TO FALL ALOFT WITH
THE APPROACH OF THE UPPER TROUGH. SOUNDING FORECASTS INDICATE THAT
UNSTABLE CONDITIONS LAST WELL INTO THIS EVENING AS HEIGHTS
CONTINUE TO FALL. SOME THUNDERSTORMS MAY CONTINUE TO BE SCATTERED
AROUND WELL INTO THE EVENING TONIGHT. SHOWERS ARE THEN EXPECTED TO
TAPER OFF TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AN UPPER LOW WILL MOVE NORTH OF THE REGION TUESDAY...WHILE A
SECONDARY SURFACE COLD FRONT/TROF CROSS THE FORECAST AREA. EXPECT
MOSTLY CLOUDY SKIES ALONG WITH A CHANCE OF SHOWERS/THUNDERSTORMS
ACROSS NORTHERN AREAS TUESDAY...WITH PARTLY SUNNY SKIES ALONG WITH
A CHANCE OF SHOWERS ACROSS CENTRAL AND DOWNEAST AREAS. THE UPPER
LOW WILL MOVE NORTHEAST TUESDAY NIGHT WHILE SURFACE HIGH PRESSURE
BEGINS TO BUILD EAST. AN EVENING SHOWER IS POSSIBLE ACROSS
NORTHERN AREAS EARLY TUESDAY NIGHT...WITH DECREASING CLOUDS
OVERNIGHT. PARTLY CLOUDY/MOSTLY CLEAR SKIES ARE EXPECTED ACROSS
CENTRAL AND DOWNEAST PORTIONS OF THE FORECAST AREA TUESDAY NIGHT.
SURFACE HIGH PRESSURE WILL CROSS THE REGION WEDNESDAY THROUGH
WEDNESDAY NIGHT. AN UPPER DISTURBANCE CROSSING THE REGION
WEDNESDAY WILL BRING PARTLY SUNNY SKIES TO THE FORECAST AREA.
PARTLY CLOUDY/MOSTLY CLEAR SKIES ARE EXPECTED ACROSS NORTHERN
AREAS WEDNESDAY NIGHT...WITH MOSTLY CLEAR SKIES ACROSS
CENTRAL/DOWNEAST AREAS. TEMPERATURES WILL BE AT SLIGHTLY BELOW
NORMAL LEVELS TUESDAY...WITH NEAR NORMAL LEVEL TEMPERATURES
WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION EARLY THURSDAY WITH A
WARM FRONT APPROACHING LATE. PARTLY SUNNY SKIES ARE EXPECTED
ACROSS THE REGION THURSDAY...WITH MOSTLY CLOUDY SKIES AND A
CHANCE OF SHOWERS THURSDAY NIGHT. A COLD/OCCLUDED FRONT WILL CROSS
THE REGION FRIDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
OTHER COLD FRONTS/TROFS WILL CROSS THE REGION BOTH SATURDAY AND
SUNDAY BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
FORECAST AREA...WITH THE BETTER CHANCES ACROSS NORTHERN AREAS.
TEMPERATURES WILL BE AT NEAR NORMAL LEVELS THURSDAY...WITH
SLIGHTLY BELOW NORMAL LEVEL TEMPERATURES FRIDAY THROUGH SUNDAY.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
NEAR TERM: GENERALLY IFR TO OCCASIONALLY MVFR CONDITIONS IN
SHOWERS AND LOW CLOUDS ARE EXPECTED TODAY AND TONIGHT.
SHORT TERM: VARIABLE CONDITIONS ARE POSSIBLE WITH ANY
SHOWERS/THUNDERSTORMS TUESDAY INTO TUESDAY EVENING.
OTHERWISE...GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS THE
REGION TUESDAY THROUGH MUCH OF THURSDAY. VARIABLE CONDITIONS ARE
POSSIBLE WITH SHOWERS/THUNDERSTORMS AGAIN FRIDAY.
&&
.MARINE...
NEAR TERM: WINDS ARE EXPECTED TO BE LIGHT TODAY AND TONIGHT. FOG
WILL LIKELY LIMIT VISIBILITIES OVER THE WATERS EARLY TODAY.
SHORT TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY LEVELS TUESDAY THROUGH FRIDAY. VISIBILITIES COULD BE
REDUCED IN SHOWERS THURSDAY NIGHT INTO FRIDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORCROSS
LONG TERM...NORCROSS
AVIATION...VJN/NORCROSS
MARINE...VJN/NORCROSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
759 PM EDT TUE JUL 30 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 314 PM EDT TUE JUL 30 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A WNW FLOW ALF
OVER THE NRN TIER CONUS AND OVER THE UPR LKS BTWN A SPRAWLING RDG
OVER THE S AND A TROF OVER CNTRL CANADA. SOME SCT -SHRA ASSOCIATED
WITH A DISTURBANCE THRU ONTARIO JUST N OF LK SUP IMPACTED UPR MI
EARLIER IN THE DAY...BUT THE ARRIVAL OF MUCH DRIER AIR ALF SHOWN
BEST ON THE 12Z MPX...ABERDEEN SDAKOTA...AND BISMARCK RAOBS IS
CAUSING THE SHRA TO DIMINISH THIS AFTN. STRONG CAPPING DEPICTED ON
THE LOCAL AND THOSE UPSTREAM RAOBS HAS PREVENTED ANY TS. THE CLDS
ARE A BIT MORE RESILIENT ESPECIALLY OVER THE W WITH LINGERING LLVL
MSTR SHOWN ON THOSE UPSTREAM RAOBS. FARTHER TO THE W...ANOTHER
SHRTWV MOVING FM THE NRN ROCKIES INTO THE NRN PLAINS IS INTERACTING
WITH THE MUCH MOISTER ENVIRONMENT SHOWN ON THE 12Z GLASGOW MT RAOB
AND CAUSING MORE SHRA/TS TO EXPAND INTO THE NRN PLAINS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/IMPACT ON TEMPS
TNGT AND THEN SHRA/TS CHCS LATE TNGT THRU WED ASSOCIATED WITH
DISTURBANCE NOW ROLLING INTO THE NRN PLAINS.
TNGT...WITH DRYING ALF AND LOSS OF DAYTIME HEATING...ANY LINGERING
DIURNAL -SHRA SHOULD DIMINISH ANRD 00Z...WITH THE MORE PERSISTENT
ACTIVITY ALONG DECAYING LK BREEZE BNDRY OVER THE NCENTRAL. SUPRISED
SEVERAL OF THE MODELS GENERATE PCPN THRU MUCH OF THE NGT. BUT
CONSIDERING THE MAGNITUDE OF THE DRYING SHOWN ON THE UPSTREAM RAOBS
AND LACK OF ANY SGNFT H85 THETA E ADVCTN...SUSPECT THE REST OF THE
EVNG WL FEATURE DRY WX WITH THIS MID LVL DRY AIR DOMINATING. MORE
SHRA MAY ARRIVE OVER THE W LATER TNGT AS DPVA/HGT FALLS IN ADVANCE
OF NEXT SHRTWV PUSH INTO THE AREA AND ERODE MID LVL CAPPING AND
MOISTEN THE MID LVLS. BUMPED UP POPS OVER THE W TO ACCOUNT FOR MODEL
TRENDS TOWARD FASTER ARRIVAL OF THIS DYNAMIC FORCING.
WED...SHRA/EMBEDDED TS OVER THE W IN THE MRNG IN ADVANCE OF INCOMING
SHRTWV/ATTENDANT COLD FNT WL MOVE E THRU THE DAY WITH FAIRLY POTENT
DPVA/DEEP LYR QVECTOR CNVGC. A GOOD AMOUNT OF CLD COVER/FCST NEUTRAL
TO NEGATIVE H85 THETA E ADVCTN WL LIMIT HOW MUCH DEEPER LAPSE RATES
CAN DESTABILIZE...AND MODEL FCST SDNGS SHOW NARROW/SKINNY CAPE
DESPITE MUCAPE AS HI AS 1000J/KG. SO SUSPECT SEVERE WX THREAT WL BE
QUITE LIMITED DESPITE STRENGTH OF SHRTWV/12HR HGT FALLS UP TO 60M
DURING DIURNAL HEATING TIME/DEEP LYR SHEAR 30-35KTS...ESPECIALLY
SINCE MODELS HAVE TRENDED FASTER WITH THE SHRTWV PASSAGE/COLD FROPA.
THE BETTER CHC FOR MORE WDSPRD AND STRONGER SHRA/TS WOULD BE OVER
THE E...WHERE LATER ARRIVAL OF THE FNT MIGHT ALLOW FOR MORE DIURNAL
ENHANCEMENT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 241 PM EDT TUE JUL 30 2013
MUCH OF THIS TIME PERIOD WILL BE PLAGUED BY AFTERNOON SHOWERS OR
POSSIBLE THUNDERSTORMS ACROSS MAINLY CENTRAL UPPER MICHIGAN...THANKS
TO PERSISTENT NW FLOW ALOFT USHERING IN NEARLY DAILY DISTURBANCES
THAT WILL BE ENHANCED BY DAYTIME HEATING AND POTENTIAL LAKE BREEZES.
EXPECT A NEARLY STEADY FORECAST OF THROUGH TUESDAY OF LOWS IN THE
50S /WITH A FEW UPPER 40S/ AND HIGHS IN THE 60S TO LOW 70S /WARMEST
SOUTH CENTRAL/.
BY WEDNESDAY EVENING THE MAIN SYSTEM WILL BE ON ITS WAY OUT...WITH
THE 500MB LOW SET UP ACROSS NORTHERN ONTARIO AND A BROAD TROUGH
EXTENDING FROM ALBERTA AND SASKATCHEWAN THROUGH WI AND MI. THE SLOW
MOVING SFC LOW SHOULD BE OVER N ONTARIO...WITH A COLD FRONT
EXTENDING ACROSS E UPPER MI. BEHIND THE FRONT...LIGHT W TO WNW FLOW
WILL BE THE RULE NEAR THE SFC...WITH THE SFC TROUGH SLOWLY EXITING
EASTWARD BY THE END OF THE WORK WEEK. A SECONDARY COLD FRONT/TROUGH
WILL CROSS THE REGION LATE THURSDAY AFTERNOON...WITH ANOTHER GOOD
CHANCE OF SHOWERS OR THUNDERSTORMS MAINLY INLAND FROM LAKE SUPERIOR.
HIGH PRESSURE WILL ENCOMPASS UPPER MI AND LAKE SUPERIOR LATE FRIDAY
THROUGH SUNDAY. THE GFS AND ECMWF ARE IN A SLIGHT DISAGREEMENT BY
SUNDAY NIGHT...WHICH CONTINUES THROUGH THE REMAINDER OF THE FCST
PERIOD. IT ALL STEMS FROM TIMING OF THE NEXT WAVES SWINGING IN FROM
THE NW...WITH THE GFS BUILDING IN A MORE ROBUST RIDGE AT THE SFC AND
ALOFT SUNDAY NIGHT. EXPECT WAA TO BEGIN OVER THE W LATE
SUNDAY...WITH HIGH CLOUDS ENCROACHING IN ADVANCE OF LOW PRESSURE
ORGANIZING ACROSS THE PLAINS STATES. WE MAY END UP DRY ON
MONDAY...AS THE 30/00Z IS MUCH WEAKER AND SLOWER WITH THE LOW WHEN
COMPARED TO THE 30/12Z GFS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 757 PM EDT TUE JUL 30 2013
FEED OF LOW-LEVEL MOISTURE FROM THE SW WILL LEAD TO OCNL MVFR CIGS
AT KIWD THIS EVENING. WILL NEED TO MONITOR TRENDS TO SEE IF THESE
MVFR CIGS SPREAD FARTHER N AND E TO REACH KCMX/KSAW. OTHERWISE...VFR
CONDITIONS SHOULD PREVAIL THRU TONIGHT. WHILE THE NIGHTTIME HRS
SHOULD BE DRY...THERE MAY BE A FEW -SHRA AROUND THE AREA...THOUGH
CONFIDENCE IS TOO LOW TO INCLUDE MENTION. BETTER OPPORTUNITY FOR
SHRA WILL ARRIVE WED MORNING INTO THE AFTN AS COLD FRONT SWINGS THRU
THE UPPER LAKES. ANY HEAVIER SHRA COULD BRING MVFR CONDITIONS. THERE
MAY BE A FEW TSRA AS WELL...ESPECIALLY ACROSS CNTRL UPPER MI...BUT
TSRA WILL DEPEND ON AMOUNT OF DAYTIME HEATING TO GENERATE
INSTABILITY. FOR NOW...DID NOT INCLUDE TSRA IN FCST. PCPN CHC WILL
END NW TO SE DURING THE AFTN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 314 PM EDT TUE JUL 30 2013
EXPECT WINDS NO HIGHER THAN 20 KTS THIS FORECAST PERIOD WITH A WEAK
PRESSURE GRADIENT DOMINATING THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
345 PM EDT MON JUL 29 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 251 PM EDT MON JUL 29 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE WRN GRT LKS BTWN SLOWLY DEPARTING CUTOFF LO JUST S OF
JAMES BAY AND AN UPR RDG OVER MN. THE ARRIVAL OF SFC HI PRES/ACYC
FLOW AND DRIER AIRMASS SHOWN ON THE 12Z INL RAOB ARE BRINGING A
MOSUNNY DAY TO THE CWA. LOOKING UPSTREAM...A SHRTWV IS MOVING INTO
THE NRN PLAINS IN THE WSW FLOW ALF BTWN THE UPR RDG OVER MN AND A
TROF OVER SW CANADA. THERE ARE SOME SHRA/TS ASSOCIATED WITH THIS
FEATURE...AND SOME CLDS WELL IN ADVANCE OF THE SHRA ARE SPILLING
INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM ARE MIN TEMPS TNGT AND THE CHC
FOR SOME SHRA ON TUE.
TNGT...UPR RDG AXIS IS PROGGED TO DRIFT W-E OVER UPR MI TNGT.
FOLLOWING THE PASSAGE OF THE UPR RDG...SOME MSTR IN ADVANCE OF
SHRTWV MOVING INTO MN IS FCST TO SPREAD INTO THE WRN CWA. IN CONCERT
WITH INCRSG WSW FLOW AT H925 ON THE BACK SIDE OF RETREATING SFC HI
PRES TO THE E...THE FALL OF TEMP OVER THE NW PORTIONS OF THE CWA
SHOULD BE HELD IN CHECK A BIT. THE BEST CHC FOR MIN TEMPS FALLING
FARTHER INTO THE 40S WL BE OVER THE INTERIOR SCENTRAL AND E...WHERE
THE CLDS WL ARRIVE LATEST CLOSER TO THE RETREATING HI.
TUE...A NUMBER OF MODELS GENERATE SOME MAINLY LGT PCPN OVER UPR MI
AS SHRTWV DRIFTS TO THE E AND INTERACTS WITH MODEST RETURN OF
SOMEWHAT HIER H85 THETA E. SUSPECT THE BEST CHC FOR SOME SHRA WL BE
IN THE AFTN WITH DAYTIME HEATING AND SOME LLVL CNVGC ON LK BREEZE
BNDRYS. SYNOPTIC SCALE SW FLOW SHOULD LIMIT INLAND PENETRATION OF
BREEZE OFF LK SUP. SINCE MODEL FCST SDNGS CONTINUE TO EXHIBIT
RELATIVELY WARM MID LVLS TEMPS/SOME CAPPING AOA H7/MARGINAL MID LVL
LAPSE RATES...WENT NO HIER THAN SCHC POPS AND KEPT OUT THE MENTION
OF TS FOR NOW WITH LIMITED INSTABILITY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 344 PM EDT MON JUL 29 2013
WE WILL START THIS LONG TERM PERIOD OUT WITH WESTERLY FLOW AT
500MB...WITH A RIDGE STUCK ACROSS THE SOUTHERN U.S. AND THE NEXT OF
A SERIES OF LOWS SET UP ACROSS MANITOBA.
THE 500MB LOW OVER MANITOBA WILL SHIFT ACROSS WESTERN AND CENTRAL
ONTARIO WEDNESDAY AS THE SFC RIDGE OVERHEAD EXITS TO THE SE. 850MB
TEMPS IN DECENT WAA BEHIND THE RIDGE SHOULD RISE TO AROUND 13C
BEFORE COLD FRONT SWEEPS IN FROM THE WNW DURING THE AFTERNOON AND
EARLY EVENING HOURS. TIMING LOOKS TO BE SIMILAR WITH THE AVAILABLE
MODEL GUIDANCE...WITH SHOWERS AND THUNDERSTORMS REMAINING MAINLY TO
OUR W OR OVER LAKE SUPERIOR THROUGH 12Z WEDNESDAY...AROUND 0.25IN
OVER THE W TIER OF COUNTIES BY 18Z...AND CENTRAL AND E DURING THE
MID TO LATE AFTERNOON HOURS. THERE ARE A COUPLE OF OUTLIERS. THE
29/12Z REGIONAL WRF AND CANADIAN RUNS WERE EITHER TOO STRONG OR TOO
WEAK WITH THE SHORTWAVES ROTATING THROUGH...AS THE 500MB TROUGH
BEGINS TO SWING INTO UPPER MI ON WEDNESDAY. VARIABLE PRECIPITATION
OUTPUTS OF NEARLY NOTHING TO AROUND AN INCH WERE THE RESULT. THE WRF
AND CANADIAN RUNS WERE EXCLUDED FROM MUCH OF THIS FCST...GIVEN THE
LOWER CONFIDENCE IN EITHER SOLUTION.
EXPECT THE COLD FRONT TO BE OVER FAR EASTERN UPPER MI BY 06Z
THURSDAY...WITH COOLER AIR FILTERING IN FROM THE NW ONCE AGAIN.
850MB TEMPS SHOULD FALL TO AROUND 8C BY DAYBREAK THURSDAY...WITH
LOWS NEAR 50F OVER THE W HALF OF UPPER MI WITH W WINDS HOVERING NEAR
10KTS.
NO REAL WARM UP IS EXPECTED FOR THURSDAY THROUGH THE UPCOMING
WEEKEND AS A SERIES OF DISTURBANCES SWINGING IN FROM THE NW HELP
KEEP THEM IN CHECK. THERE COULD BE SOME POP UP AFTERNOON SHOWERS OR
EVEN A THUNDERSTORM THURSDAY AFTERNOON INLAND FROM LAKE
SUPERIOR...AS ANOTHER SHORTWAVE ROTATES AROUND THE MAIN 500MB LOW
STUCK NEAR AND ACROSS HUDSON BAY. A SLIGHTLY MORE SIGNIFICANT SFC
TROUGH/500MB SHORTWAVE WILL SLIDE ACROSS FRIDAY AFTERNOON...WITH
ADDITIONAL CLOUD COVER...SHOWERS...AND INLAND POP UP THUNDERSTORMS.
YET ANOTHER ROUND OF SHOWERS WILL BE POSSIBLE SATURDAY...ALTHOUGH
LIKELY FARTHER EAST AS THE ENTIRE SYSTEM SHIFTS EASTWARD AND THE SFC
RIDGE BEGINS TO SHIFT IN. EXPECT DRY WEATHER SUNDAY AS THE SFC HIGH
PUSHES OVERHEAD...EVEN THROUGH NW FLOW LINGERS ALOFT. WITH THE
29/12Z ECMWF SHOWING 850MB TEMPS ON AROUND 7C AND LIGHT N
WINDS...60S AND LOW 70S STILL LOOK REASONABLE FOR HIGH TEMPS. AS FOR
DAY 7/MONDAY...THE SFC HIGH DOES NOT LOOK TO MOVE MUCH...BUT A WAVE
SLIDING THROUGH THE NW FLOW COULD BRING A PARTLY CLOUDY SKY TO THE W
WITH A FEW SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 131 PM EDT MON JUL 29 2013
ALTHOUGH SOME MID CLDS AND PERHAPS A FEW -SHRA WL SPILL INTO UPR MI
LATER TNGT/TUE IN ADVANCE OF A DISTURBANCE MOVING E INTO MN...EXPECT
VFR CONDITIONS TO PREDOMINATE AT ALL 3 TAF SITES WITH LINGERING LLVL
DRY AIR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 251 PM EDT MON JUL 29 2013
EXPECT WINDS NO HIER THAN 20 KTS THIS FORECAST PERIOD WITH WEAK PRES
GRADIENT DOMINATING THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
252 PM EDT MON JUL 29 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 251 PM EDT MON JUL 29 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE WRN GRT LKS BTWN SLOWLY DEPARTING CUTOFF LO JUST S OF
JAMES BAY AND AN UPR RDG OVER MN. THE ARRIVAL OF SFC HI PRES/ACYC
FLOW AND DRIER AIRMASS SHOWN ON THE 12Z INL RAOB ARE BRINGING A
MOSUNNY DAY TO THE CWA. LOOKING UPSTREAM...A SHRTWV IS MOVING INTO
THE NRN PLAINS IN THE WSW FLOW ALF BTWN THE UPR RDG OVER MN AND A
TROF OVER SW CANADA. THERE ARE SOME SHRA/TS ASSOCIATED WITH THIS
FEATURE...AND SOME CLDS WELL IN ADVANCE OF THE SHRA ARE SPILLING
INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM ARE MIN TEMPS TNGT AND THE CHC
FOR SOME SHRA ON TUE.
TNGT...UPR RDG AXIS IS PROGGED TO DRIFT W-E OVER UPR MI TNGT.
FOLLOWING THE PASSAGE OF THE UPR RDG...SOME MSTR IN ADVANCE OF
SHRTWV MOVING INTO MN IS FCST TO SPREAD INTO THE WRN CWA. IN CONCERT
WITH INCRSG WSW FLOW AT H925 ON THE BACK SIDE OF RETREATING SFC HI
PRES TO THE E...THE FALL OF TEMP OVER THE NW PORTIONS OF THE CWA
SHOULD BE HELD IN CHECK A BIT. THE BEST CHC FOR MIN TEMPS FALLING
FARTHER INTO THE 40S WL BE OVER THE INTERIOR SCENTRAL AND E...WHERE
THE CLDS WL ARRIVE LATEST CLOSER TO THE RETREATING HI.
TUE...A NUMBER OF MODELS GENERATE SOME MAINLY LGT PCPN OVER UPR MI
AS SHRTWV DRIFTS TO THE E AND INTERACTS WITH MODEST RETURN OF
SOMEWHAT HIER H85 THETA E. SUSPECT THE BEST CHC FOR SOME SHRA WL BE
IN THE AFTN WITH DAYTIME HEATING AND SOME LLVL CNVGC ON LK BREEZE
BNDRYS. SYNOPTIC SCALE SW FLOW SHOULD LIMIT INLAND PENETRATION OF
BREEZE OFF LK SUP. SINCE MODEL FCST SDNGS CONTINUE TO EXHIBIT
RELATIVELY WARM MID LVLS TEMPS/SOME CAPPING AOA H7/MARGINAL MID LVL
LAPSE RATES...WENT NO HIER THAN SCHC POPS AND KEPT OUT THE MENTION
OF TS FOR NOW WITH LIMITED INSTABILITY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 342 AM EDT MON JUL 29 2013
LITTLE CHANGE TO THE LONG TERM FORECAST OVER THE LAST 24 HOURS WITH
THE PRIMARY WEATHER MAKER FOR THE PERIOD BEING A COLD FRONT MOVING
THROUGH ON WEDNESDAY.
UPPER MICHIGAN WILL BE UNDER AN SURFACE RIDGE AND EXITTING WEAK
UPPER RIDGE ON TUESDAY MORNING. AFTER A COOL START...TEMPERATURES
SHOULD WARM UP QUICKLY UNDER INCREASING HIGH CLOUDS FROM THE WEST
AND HIGHS WILL BE IN THE 70S. WITH A SHORTWAVE MOVING ACROSS LAKE
SUPERIOR DURING THE MORNING AND FIRST PART OF THE
AFTERNOON...QUESTION BECOMES WHETHER THERE WILL BE ENOUGH MOISTURE
FOR SHOWER DEVELOPMENT. MODELS HAVE TRENDED UP MOISTURE OVER THE
LAST 24 HOURS AND INDICATE MORE DIURNAL CLOUD DEVELOPMENT OVER THE
CENTRAL AND EAST...ESPECIALLY NEAR THE WEAK LAKE BREEZE CONVERGENCE
AROUND LAKE SUPERIOR. WITH THIS INCREASE IN MOISTURE...MORE MODELS
ARE HINTING AT LIGHT SHOWER DEVELOPMENT (ESPECIALLY IN THE HI-RES
MODELS). INSTABILITY IS FAIRLY MARGINAL AND WITH A CAP AROUND
10KFT...WOULDN/T EXPECT THE CLOUDS TO BUILD TOO MUCH...BUT FELT
THERE WAS ENOUGH INDICATION OF SOME SHOWERS TO MENTION A SLIGHT
CHANCE BY THE LAKE BREEZE IN NORTH CENTRAL AND EAST. KEPT THUNDER
OUT OF THE FORECAST SINCE CLOUD DEPTH IS SHALLOW AND THE CAP WILL
KEEP THE CLOUD ABOVE FREEZING.
PRECIPITATION CHANCES WILL REMAIN LIMITED ON TUESDAY NIGHT UNTIL
THE STRONG SHORTWAVE ARRIVES OVER THE WESTERN U.P. LATE WEDNESDAY
MORNING AND MOVES ACROSS THE REST OF THE U.P. ON WEDNESDAY
AFTERNOON AND EVENING. WITH GROWING CONFIDENCE IN PRECIPITATION
OCCURRING...WILL TREND VALUES UP TO LIKELY OVER PORTIONS OF THE CWA
AND TRY TO PROVIDE BETTER TIMING ON THE SHOWERS MOVING THROUGH
FROM WEST TO EAST. WILL CAP THUNDER AT CHANCE PROBS SINCE MLCAPE IS
BELOW 600J/KG OVER THE ENTIRE AREA. MODELS ARE ALL OVER THE PLACE ON
THE EFFECT SHEAR FOR THE THUNDERSTORMS /20-40KTS/...BUT WITH THE
MARGINAL INSTABILITY...DON/T THINK THERE IS MUCH SEVERE CONCERN.
WEAK INSTABILITY IN AN AREA WHERE THERE WILL LIKELY BE A BROAD AREA
OF SHOWERS DOESN/T LEND ITSELF TO SEVERE WEATHER...ESPECIALLY IF
CLOUDS AND RAIN SPREAD NORTHEAST AHEAD OF THE FRONT UNDER THE WARM
AIR ADVECTION. OUT OF THE ENTIRE AREA...THE BEST OPPORTUNITY FOR
STRONGER THUNDERSTORMS WOULD BE OVER THE SOUTH CENTRAL...WHERE THE
INGREDIENTS OVERLAP THE BEST AND FRONT TIMING TOWARDS PEAK HEATING
OCCURS.
THROUGH JULY 28TH...OUR OFFICE IS UP TO THE 8TH WETTEST JULY
ON RECORD. THE ADDITIONAL RAIN ON WEDNESDAY...LIKELY A QUARTER OF AN
INCH OR MORE...SHOULD EASILY PUSH THIS JULY INTO THE TOP 5 WETTEST
JULY/S ON RECORD. THE FRONT AND DEEPER MOISTURE WILL QUICKLY DEPART
FROM WEST TO EAST WEDNESDAY EVENING AND EARLY OVERNIGHT HOURS AND
WILL CONTINUE THE TREND TOWARDS DRY AND CLEARING.
BEHIND THE SHORTWAVE...THE AREA WILL BE ON THE SOUTHWEST SIDE OF THE
UPPER TROUGH ROTATING IN NORTHERN ONTARIO AND SLOWLY MOVING EAST
INTO QUEBEC THIS WEEKEND. MOST LOCATIONS WILL BE DRY ON
THURSDAY...BUT MOISTURE WRAPPING AROUND THE UPPER LOW WILL LEAD TO
PARTLY CLOUDY SKIES OVER PORTIONS OF THE AREA WITH DIURNAL
HEATING...ESPECIALLY OVER THE EAST. ANOTHER SHORTWAVE DOES ROTATE
AROUND THE UPPER LOW ON THURSDAY AFTERNOON...SO DID MENTION SOME
SHOWERS NEAR LAKE MICHIGAN WHERE THERE WILL BE THE GREATEST
INSTABILITY.
FRIDAY INTO THE WEEKEND WILL BE DOMINATED BY THE NORTHWEST FLOW
ALOFT...ALTHOUGH THE AREA WILL BE ON THE EDGE OF THE WEATHER FROM
THE UPPER LOW AND THE OTHER WAVES MOVING THROUGH THE CENTRAL PLAINS
AND LOWER GREAT LAKES. EXPECT THIS TO PRODUCE MAINLY DRY
CONDITIONS...ALTHOUGH AN OCCASIONAL SHOWER CAN/T BE COMPLETELY
RULED OUT AS SHORTWAVES ROTATE AROUND THE UPPER LOW. A HIGH PRESSURE
RIDGE WILL SLOWLY NOSE INTO THE SOUTHWEST HALF OF THE CWA SATURDAY
AND SUNDAY FROM A HIGH CENTERED NEAR LAKE WINNIPEG. TEMPERATURES
THURSDAY THROUGH THE WEEKEND WILL BE A LITTLE BELOW NORMAL...WITH
HIGHS IN THE MID 60S TO LOWER 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 131 PM EDT MON JUL 29 2013
ALTHOUGH SOME MID CLDS AND PERHAPS A FEW -SHRA WL SPILL INTO UPR MI
LATER TNGT/TUE IN ADVANCE OF A DISTURBANCE MOVING E INTO MN...EXPECT
VFR CONDITIONS TO PREDOMINATE AT ALL 3 TAF SITES WITH LINGERING LLVL
DRY AIR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 251 PM EDT MON JUL 29 2013
EXPECT WINDS NO HIER THAN 20 KTS THIS FORECAST PERIOD WITH WEAK PRES
GRADIENT DOMINATING THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1050 PM MDT Sun Jul 28 2013
UPDATED AVIATION SECTION
.DISCUSSION...
An update for minor changes to the forecast. After a fairly active
evening with strong to severe thunderstorms over north central
and central Montana, the storms have quieted down. A storm with
heavy rain persists over the hi- line near Cut Bank, otherwise
lighter showers and some thunderstorms exist over central and
southwest Montana. A surge of moisture is expected to drop south
from Alberta overnight. Along with a weak upper level disturbance,
additional precipitation is expected - mainly over the hi-line. The
HRRR and RUC do indicate nocturnal precipitation/thunderstorms. As
a result, have bumped the pops over north central Montana
overnight. Other than this, the wind forecast was tweaked in the
period before midnight. Otherwise, no changes to the forecast. db
&&
.AVIATION...
UPDATED 0450Z.
The airmass remains somewhat unstable and showers and thunderstorms
continue to develop. Convective activity should continue overnight
as a weak cold front pushes south out of Canada and will bring an
influx of moisture with it. Areas of low clouds and rain may develop
behind the front, mainly across the Hi-Line. VFR conditions prevail
with MVFR conditions in the vicinity of thunderstorms. Increasing
MVFR conditions are possible after 08z associated with rain showers.
&&
.PREV DISCUSSION...
/ISSUED 550 PM MDT Sun Jul 28 2013/
Tonight through Tuesday...Not much change in the weather can be
expected in the short term period. An upper level low over Central
Alberta/Saskatchewan will remain quasi-stationary through Monday
night before an upper ridge builds over the Pacific Northwest and
Northern Rockies causing the low to accelerate east. Montana will
remain under a generally moist and somewhat unstable southwest to
westerly flow aloft through the short term for scattered showers
and thunderstorms each day. At this time there is nothing to
indicate that storms will become severe but they will become
increasingly moist as precipitable water levels increase across
the region and could bring locally heavy rain and possible
flooding concerns. Temperatures will remain near seasonable levels
each day. mpj
Tuesday Night through Sunday...Medium range forecast models
generally agree on the overall solution through most of the
period, only slightly disagreeing for the upcoming weekend. A weak
upper level ridge of high pressure will remain centered over
western Montana Tuesday night. However, weak disturbances moving
through the ridge will generally keep a slight chance of showers
and thunderstorms over the area. An upper level low pressure area
over the Pacific Northwest coast will then gradually move onshore
and across the Pacific Northwest Wednesday through Friday,
shifting the flow aloft to a more moist and unstable southwesterly
one. Disturbances ejecting from the upper low will move through
the flow and over the area, which the models reflect in higher
precipitation amounts over the area. Have therefore increased the
chances for precipitation during this period, especially so in the
mountains and over the plains of north central/central Montana.
This is due to the fact that the models tend to keep winds
easterly over the plains as surface high pressure remains east of
the area. These easterly winds will advect surface moisture into
the plains areas and move the moisture up the slopes of the Rocky
Mountain Front, making for efficient generation of precipitation.
The unstable flow aloft will also keep at least a slight chance of
thunderstorms around as well through the period, but the increased
chance of wet thunderstorms will help limit new fire starts due to
lightning strikes. Temperatures on Wednesday will warm to a few
degrees below seasonal averages, but the disturbances and
resulting precipitation will help keep high temperatures 5 to 10
degrees below average for this period. The high pressure ridge
will then rebuild into the state from the south for the weekend,
causing the upper low to retrograde back towards the Pacific
Northwest coast. This will decrease the chance of precipitation
and allow temperatures to warm back closer to normal by Sunday.
The only discrepancy is that the ECMWF model is a bit faster than
the GFS/GEM models in rebuilding this ridge, which would mean a
bit quicker of a warm up. Will monitor this situation over the
next few days and make adjustments accordingly. Coulston
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 50 74 51 78 / 40 30 20 20
CTB 48 68 47 72 / 40 20 20 20
HLN 54 79 53 83 / 30 20 10 30
BZN 48 80 48 83 / 30 30 20 20
WEY 36 74 38 74 / 30 20 20 20
DLN 47 81 47 83 / 20 10 10 20
HVR 52 73 51 74 / 40 30 30 30
LWT 51 71 50 75 / 50 50 30 40
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS HASTINGS NE
638 PM CDT TUE JUL 30 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 246 PM CDT TUE JUL 30 2013
MAIN UPPER LEVEL SCENARIO INCLUDES A PERSISTENT SUBTROPICAL RIDGE
OVER THE SOUTHERN UNITED STATES. SPLIT JET WITHIN QUASI-ZONAL FLOW
IN THE NORTH CONTAINS A SHORTWAVE TROUGH SKIRTING ACROSS THE
NORTHERN PLAINS WHICH SHOULD DEVELOP A LONG ADVERTISED MCS OVER
SOUTH DAKOTA THAT SHOULD MAKE ITS WAY SOUTHEAST...AND COULD JUST
SWIPE THE CWA IN THE NORTH BY LATE TONIGHT. THERE COULD BE ENOUGH
SHEAR TO GET SOME STRONG TO SEVERE WEATHER FROM THE REMNANTS OF THE
EXPECTED MCS. CONVERGENCE ALONG AN APPROACHING COLD FRONT WILL ALSO
INCREASE PRECIPITATION AND SEVERE THUNDERSTORM CHANCES. AS A SIDE
NOTE...SKY COVER IS DIFFICULT TO FORECAST FOR THIS EVENING...AND I
HAVE CURBED THE ENTHUSIASM OF MOST MODELS FOR CLEARING...AS EVEN
THE HRRR HAS SHOWN TOO MUCH OPTIMISM FOR THE CLEARING.
ALSO...MODELS HAVE CONTINUED TO ADVERTISE A FAIRLY STRONG SIGNAL FOR
FOG AND HAVE BEEN PRETTY CONSISTENT AS STRATUS IS FORECAST TO
LOWER UNTIL WE GET DENSE FOG IN OUR EAST. CONFIDENCE IS HIGHER WITH
THE RECENT CONSISTENCY...AND A FAIRLY STRONG SIGNAL IN THE
EASTERN THIRD OF THE CWA PERSISTS...PROMPTING ME TO ISSUE A DENS
FOG ADVISORY FOR LATE TONIGHT INTO WEDNESDAY MORNING.
A COLD FRONT WILL MAKE ITS WAY ACROSS THE CWA FOR WEDNESDAY AND WILL
BE THE FOCUS FOR MORE POSSIBLE SEVERE WEATHER. DEWPOINTS ARE
EXPECTED TO POOL NEAR THE BOUNDARY WITH INCREASED INSTABILITY ALONG
THE FRONT...AND CONTINUED LOW-LEVEL CONVERGENCE. BULK SHEAR WILL
ALSO BE SUFFICIENT ENOUGH FOR SEVERE WEATHER...EVEN IF THERE ARE
LIMITED BREAKS IN SKY COVER. THIS COULD WIND UP BEING A POTENTIALLY
INTERESTING DAY DEPENDING ON THE TIMING OF THE COLD FRONT. KEPT A
CHANCE OF PRECIPITATION NEAR THE FRONT...SIMILAR TO THE PREVIOUS
FORECAST.
BASED TEMPERATURES AND DEWPOINTS ON RECENT MODEL PERFORMANCE AND NOT
MUCH HAS CHANGED FOR THESE FIELDS COMPARED TO THE PREVIOUS
FORECAST...EXCEPT PERHAPS HIGHER DEWPOINTS NEAR THE PROJECTED TIMING
AND PLACEMENT OF THE COLD FRONT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUL 30 2013
GUIDANCE SUGGESTS NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST
OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG TERM FORECAST
PERIOD. WITH MULTIPLE MID LEVEL PERTURBATIONS PERHAPS MOVING OVER
THE AREA WITHIN THE MEAN MID LEVEL FLOW...POPS REMAIN LITTERED
THROUGHOUT MOST ALL OF THE LONG TERM FORECAST PERIOD. OUT OF ALL THE
LONG TERM FORECAST PERIODS...THE HIGHEST CONFIDENCE WITH RESPECT TO
POPS EXISTS DURING THURSDAY AND THURSDAY NIGHT. THESE ARE TIME
PERIODS IN WHICH GUIDANCE SUGGESTS LOW LEVEL THERMAL ADVECTION AND
RESULTANT ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY ALONG THE
315-320K SURFACES...WILL PERSIST. THIS THERMAL ADVECTION...WORKING IN
CONCERT WITH OMEGA FROM MID LEVEL PERTURBATIONS PUSHING
OVERHEAD...SHOULD BE STRONG ENOUGH TO PROMOTE PRECIPITATION
PRODUCTION ACROSS MUCH OF OUR AREA. TAKING A AVERAGE OF THE
NAM...OPERATIONAL GFS...EC...AND SREF-MEAN PROVIDES BETWEEN A
QUARTER INCH AND A HALF INCH OF RAIN ACROSS MUCH OF OUR CWA DURING
THE DAY THURSDAY...AND MUCH OF THE SAME ACROSS OUR EAST THURSDAY
NIGHT. WENT AHEAD AND INCREASED POPS ACROSS MUCH OF OUR CWA THURSDAY
INTO THURSDAY NIGHT AS A RESULT. POPS ALSO CONTINUE ACROSS OUR AREA
FOR THE MOST PART HEADING INTO FRIDAY BEFORE THE PRIMARY AXIS OF
THERMAL ADVECTION FINALLY EXITS THE AREA TO THE EAST. AS MENTIONED
ALREADY...THE POTENTIAL FOR MID LEVEL PERTURBATIONS MOVING OVER THE
AREA SUGGESTS POPS REMAIN WARRANTED ACROSS OUR AREA THROUGH THE
REMAINDER OF THE EXTENDED FORECAST PERIOD. ALLBLEND PROVIDED A
VARIETY OF POPS TO OUR AREA EACH DAY...GENERALLY IN THE 20-40%
RANGE...AND GIVEN THE LOW PROBABILITY OF IMPROVING THE FORECAST
THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART.
INCREASING LOW LEVEL RETURN FLOW AND RESULTANT MOISTURE FLUX INTO
THE AREA SHOULD HELP PROMOTE RESPECTABLE VALUES OF POTENTIAL
INSTABILITY ON THURSDAY...WITH GUIDANCE FROM THE NAM...OPERATIONAL
GFS...AND EC SUGGESTING MUCAPE VALUES RANGING BETWEEN 1500 AND
3500J/KG ACROSS OUR CWA. DEEP LAYER BULK SHEAR VALUES OF 35-45KTS
ARE ALSO FORECAST ACROSS THE AREA ON THURSDAY. THERE IS A CONCERN
THAT EXPANSIVE CLOUD COVER WILL KEEP LOW LEVEL TEMPERATURES ON THE
COOL SIDE WHICH WOULD HELP PRESERVE A LOW LEVEL CAPPING
INVERSION...WHICH WOULD OBVIOUSLY INHIBIT STRONG/DEEP CONVECTION
FROM BEING REALIZED. THAT BEING SAID...IF NEAR-SURFACE BASED
CONVECTION CAN BE REALIZED THURSDAY...THEN CERTAINLY SEVERE WEATHER
WILL BE POSSIBLE AND WILL INTRODUCE SUCH WORDING TO THE HWO. BEYOND
THURSDAY...GUIDANCE SUGGESTS MUCAPE VALUES IN EXCESS OF 2000J/KG
COULD BE REALIZED MOST ANY DAY...BUT AS ALREADY MENTIONED CONFIDENCE
ON WHEN AND WHERE CONVECTION WILL BE REALIZED IS VERY LOW AND AS A
RESULT...WILL MAINTAIN VAGUE SEVERE WEATHER WORDING IN THE HWO FOR
FRIDAY AND BEYOND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 632 PM CDT TUE JUL 30 2013
STRATUS WILL BE THE BIGGEST TOSS UP FOR THIS FORECAST. MODELS ARE
PERFORMING POORLY AND ARE OF LITTLE HELP. JUST TOOK A BEST GUESS
BASED ON PATTERN RECOGNITION AND WENT WITH PREDOMINANTLY MVFR
CONDITIONS OVERNIGHT...HOWEVER THE TERMINAL IS ON THE FAR
NORTHWESTERN EDGE OF STRATUS AND IS TEETERING ON THE MVFR/VFR
MARGINS. WIND WILL BE LIGHT AND REDUCED VISIBILITY HAS BEEN
CONSISTENTLY ADVERTISED OVER THE PAST FEW DAYS. THE WORST
VISIBILITY SHOULD REMAIN EAST OF THE TERMINAL. THERE IS A VERY
SLIGHT CHANCE OF A THUNDERSTORM LATE TONIGHT...PRIMARILY AFTER
09Z...BUT MOST OF THE ACTIVITY IS STILL EXPECTED TO REMAIN NORTH
OF THE TERMINAL. THERE IS ALSO A VERY OUTSIDE CHANCE OF SOME
STRONG WIND GUSTS. A LULL IS EXPECTED DURING THE DAY ON
WEDNESDAY...AND BY LATE AFTERNOON/EARLY EVENING...MORE STORMS
COULD FIRE ALONG A COLD FRONT IN THE VICINITY...BUT PROBABLY NOT
UNTIL LATE AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY FROM 4 AM TO 10 AM CDT WEDNESDAY FOR NEZ041-
048-049-063-064-076-077-086-087.
KS...DENSE FOG ADVISORY FROM 4 AM TO 10 AM CDT WEDNESDAY FOR KSZ007-
019.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...BRYANT
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1249 PM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT MON JUL 29 2013
TODAY...MULTIPLE MODES OF ATMOSPHERIC UNREST ARE OPERATING ACROSS
THE FCST AREA THIS MORNING AND ARE EXPECTED TO CONTINUE THROUGH
THIS EVENING. STRATUS...FOG...DRIZZLE...SHOWERS PRODUCING DECENT
RAINFALL IN A WARM CLOUD PROCESS ARE OPERATING ACROSS SWRN NEB
THROUGH NCNTL NEBRASKA THIS MORNING. THIS AREA OF WEATHER IS
EXPECTED TO SHIFT EAST THIS MORNING AND COVER AREAS ALONG AND
EAST OF HIGHWAY 183 THIS AFTERNOON. IT IS BELIEVED THAT THE
SHOWERS AND DRIZZLE/FOG SHOULD EXIT BY 18Z AS THIS IS BEING
DRIVEN BY MOISTURE TRANSPORT AT THE 315K SFC AND ACCORDING TO THE
RAP...THIS TRANSPORT SHOULD WEAKEN THIS MORNING.
THE ONGOING MCS ACROSS NWRN NEB IS EXPECTED TO DECAY BY 12Z AS
RADAR SUGGESTS AN OCCLUSION PROCESS IS UNDERWAY ACROSS FAR SWRN
SD. ALSO THE RAP SHOWS MOISTURE TRANSPORT ON THE 315K SFC WILL
WEAKEN.
TEMPERATURES TODAY RANGE FROM 60S ACROSS THE EAST UNDER A BLANKET
OF STRATUS TO 80S ACROSS WRN NEB WHERE IT IS BELIEVED SKIES WILL
CLEAR. THE RAP MODEL SHOWS 750MB CAPE INCREASING TO AROUND 1000
J/KG AND THE NAM THEN SHOWS THE ATM DESTABILIZING ACROSS SWRN AND
WRN NEB LATE THIS AFTERNOON. DOWN DRAFT CAPE NEAR 1000 J/KG COULD
SUPPORT A FEW STORMS WITH GUSTY WINDS...MAINLY THIS EVENING AS
THE STORMS ARE EXPECTED TO ORIGINATE ACROSS THE CYS DIVIDE AND
PARTS OF NERN COLO AND MOVE INTO THE FCST LATE THIS AFTN OR EARLY
EVENING.
TONIGHT...SCATTERED TSTMS ARE EXPECTED TO REMAIN WEST OF HIGHWAY
83 AND MAINLY ALONG AND WEST OF HIGHWAY 61. THE NAM SHOWS THESE
STORMS WEAKENING/DISSIPATING BY 03Z. A WEAK MOSTLY OUTFLOW DRIVEN
COLD FRONT IS EXPECTED TO DRAPE FROM KOGA TO KVTN IN THE WAKE OF
THE STORMS AND LOW LEVEL MOISTURE EAST OF THE FRONT APPEARS
LIKELY TO PRODUCE ANOTHER ROUND OF STRATUS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CDT MON JUL 29 2013
UPPER LEVEL RIDGE IS GENERALLY ACROSS THE 4 CORNERS REGION...AND
WILL BUILD EAST TOWARDS THE WEEKEND. MEANWHILE AN UPPER LEVEL
TROUGH/LOW WILL PUSH ACROSS CANADA MID WEEK...WITH THE LOW
REACHING THE SRN PART OF HUDSON BAY BY THE WEEKEND. OVER THE HIGH
PLAINS FLOW WILL BE NORTHWEST THROUGH THE WEEK...WITH A TRANSITION
TO MORE ZONAL BY WEEKEND.
AT THE SFC..COOL CANADIAN HIGH PRESSURE ACROSS THE CENTRAL PLAINS
EARLY...WILL SLOWLY PUSH EAST...WITH A WARM UP EXPECTED. THEN A
COLD FRONT WILL PUSH ACROSS THE AREA WEDNESDAY WITH ANOTHER COOL
DOWN TO END THE WEEK. HIGHS SHOULD RETURN TO THE 80S...NEAR OR
SLIGHTLY BELOW SEASONAL BY MID WEEK...AHEAD OF THE FRONT. BY FRIDAY
AS THE COOLER HIGH PRESSURE PUSHES ACROSS THE CENTRAL
PLAINS...TEMPS TO COOL BACK INTO THE UPPER 70S TO LOWER 80S. AFTER
THE EXTENT OF THE LATEST COOL DOWN...WILL HAVE TO MONITOR CLOSELY
THE COOLER AIR AS A TREND DOWN IN TEMPS IS POSSIBLE.
MODELS IN AGREEMENT WITH AN ACTIVE PATTERN TO CONTINUE THROUGH THE
WEEK WITH SEVERAL DISTURBANCES TO RIDE THE PERIPHERY OF THE RIDGE
AND ACROSS THE AREA. MOISTURE REMAINS DECENT WITH DEW PTS IN THE
UPPER 50S TO LOWER AND MID 60S. WITH EACH QUICK MOVING WAVE EXPECT
SHOWERS AND A FEW THUNDERSTORMS TO BE POSSIBLE.
ON WEDNESDAY...WITH THE PASSAGE OF THE COLD FRONT AND COOLER AIR
ALOFT...THERE COULD BE A FEW STRONG THUNDERSTORMS. TIMING AND
PLACEMENT OF THE BEST INSTABILITY STILL IN QUESTION...AND WILL BE
WATCH OVER THE NEXT COUPLE OF DAYS. THE REST OF THE WEEK WILL
CONTINUE TO SEE A CHANCE FOR SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH EACH PASSING WAVE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1249 PM CDT MON JUL 29 2013
THE 18Z TAF ISSUANCE FOR KLBF AND KVTN. EXPECTING THE IFR TO
MVFR CEILINGS TO LIFT FROM WEST TO EAST TODAY...WITH VFR ANTICIPATED
AT KLBF AFTER 21Z. AT KVTN...CEILINGS ARE BEGINNING TO IMPROVE
EARLY THIS AFTERNOON...SUCH THAT NO RESTRICTIONS ARE ANTICIPATED
WITHIN THE NEXT HOUR OR SO. FOR THE OVERNIGHT...NEAR TERM MODEL
GUIDANCE SUGGESTS THE LOWERED CEILINGS WILL RETURN WEST...WITH A
REPEAT OF IFR OR POSSIBLY LOWER FOR KLBF IN BOTH CEILING AND
VISIBILITY. THERE/S A BIT MORE UNCERTAINTY WITH THE NORTHWARD
EXTENT OF THE STRATUS OVERNIGHT...THUS WILL BE LESS PESSIMISTIC IN
CEILING AND VISIBILITY FORECASTS FOR KVTN. OTHERWISE STORMS ARE
POSSIBLE ACROSS THE EASTERN PANHANDLE THIS EVENING...WITH ADDITIONAL
CONVECTION POSSIBLE ACROSS NW NEBRASKA AFTER 15Z TOMORROW. STRONG
WIND GUSTS AND HAIL WOULD BE POSSIBLE WITH ANY STORM.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
618 AM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT MON JUL 29 2013
TODAY...MULTIPLE MODES OF ATMOSPHERIC UNREST ARE OPERATING ACROSS
THE FCST AREA THIS MORNING AND ARE EXPECTED TO CONTINUE THROUGH
THIS EVENING. STRATUS...FOG...DRIZZLE...SHOWERS PRODUCING DECENT
RAINFALL IN A WARM CLOUD PROCESS ARE OPERATING ACROSS SWRN NEB
THROUGH NCNTL NEBRASKA THIS MORNING. THIS AREA OF WEATHER IS
EXPECTED TO SHIFT EAST THIS MORNING AND COVER AREAS ALONG AND
EAST OF HIGHWAY 183 THIS AFTERNOON. IT IS BELIEVED THAT THE
SHOWERS AND DRIZZLE/FOG SHOULD EXIT BY 18Z AS THIS IS BEING
DRIVEN BY MOISTURE TRANSPORT AT THE 315K SFC AND ACCORDING TO THE
RAP...THIS TRANSPORT SHOULD WEAKEN THIS MORNING.
THE ONGOING MCS ACROSS NWRN NEB IS EXPECTED TO DECAY BY 12Z AS
RADAR SUGGESTS AN OCCLUSION PROCESS IS UNDERWAY ACROSS FAR SWRN
SD. ALSO THE RAP SHOWS MOISTURE TRANSPORT ON THE 315K SFC WILL
WEAKEN.
TEMPERATURES TODAY RANGE FROM 60S ACROSS THE EAST UNDER A BLANKET
OF STRATUS TO 80S ACROSS WRN NEB WHERE IT IS BELIEVED SKIES WILL
CLEAR. THE RAP MODEL SHOWS 750MB CAPE INCREASING TO AROUND 1000
J/KG AND THE NAM THEN SHOWS THE ATM DESTABILIZING ACROSS SWRN AND
WRN NEB LATE THIS AFTERNOON. DOWN DRAFT CAPE NEAR 1000 J/KG COULD
SUPPORT A FEW STORMS WITH GUSTY WINDS...MAINLY THIS EVENING AS
THE STORMS ARE EXPECTED TO ORIGINATE ACROSS THE CYS DIVIDE AND
PARTS OF NERN COLO AND MOVE INTO THE FCST LATE THIS AFTN OR EARLY
EVENING.
TONIGHT...SCATTERED TSTMS ARE EXPECTED TO REMAIN WEST OF HIGHWAY
83 AND MAINLY ALONG AND WEST OF HIGHWAY 61. THE NAM SHOWS THESE
STORMS WEAKENING/DISSIPATING BY 03Z. A WEAK MOSTLY OUTFLOW DRIVEN
COLD FRONT IS EXPECTED TO DRAPE FROM KOGA TO KVTN IN THE WAKE OF
THE STORMS AND LOW LEVEL MOISTURE EAST OF THE FRONT APPEARS
LIKELY TO PRODUCE ANOTHER ROUND OF STRATUS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CDT MON JUL 29 2013
UPPER LEVEL RIDGE IS GENERALLY ACROSS THE 4 CORNERS REGION...AND
WILL BUILD EAST TOWARDS THE WEEKEND. MEANWHILE AN UPPER LEVEL
TROUGH/LOW WILL PUSH ACROSS CANADA MID WEEK...WITH THE LOW
REACHING THE SRN PART OF HUDSON BAY BY THE WEEKEND. OVER THE HIGH
PLAINS FLOW WILL BE NORTHWEST THROUGH THE WEEK...WITH A TRANSITION
TO MORE ZONAL BY WEEKEND.
AT THE SFC..COOL CANADIAN HIGH PRESSURE ACROSS THE CENTRAL PLAINS
EARLY...WILL SLOWLY PUSH EAST...WITH A WARM UP EXPECTED. THEN A
COLD FRONT WILL PUSH ACROSS THE AREA WEDNESDAY WITH ANOTHER COOL
DOWN TO END THE WEEK. HIGHS SHOULD RETURN TO THE 80S...NEAR OR
SLIGHTLY BELOW SEASONAL BY MID WEEK...AHEAD OF THE FRONT. BY FRIDAY
AS THE COOLER HIGH PRESSURE PUSHES ACROSS THE CENTRAL
PLAINS...TEMPS TO COOL BACK INTO THE UPPER 70S TO LOWER 80S. AFTER
THE EXTENT OF THE LATEST COOL DOWN...WILL HAVE TO MONITOR CLOSELY
THE COOLER AIR AS A TREND DOWN IN TEMPS IS POSSIBLE.
MODELS IN AGREEMENT WITH AN ACTIVE PATTERN TO CONTINUE THROUGH THE
WEEK WITH SEVERAL DISTURBANCES TO RIDE THE PERIPHERY OF THE RIDGE
AND ACROSS THE AREA. MOISTURE REMAINS DECENT WITH DEW PTS IN THE
UPPER 50S TO LOWER AND MID 60S. WITH EACH QUICK MOVING WAVE EXPECT
SHOWERS AND A FEW THUNDERSTORMS TO BE POSSIBLE.
ON WEDNESDAY...WITH THE PASSAGE OF THE COLD FRONT AND COOLER AIR
ALOFT...THERE COULD BE A FEW STRONG THUNDERSTORMS. TIMING AND
PLACEMENT OF THE BEST INSTABILITY STILL IN QUESTION...AND WILL BE
WATCH OVER THE NEXT COUPLE OF DAYS. THE REST OF THE WEEK WILL
CONTINUE TO SEE A CHANCE FOR SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH EACH PASSING WAVE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 618 AM CDT MON JUL 29 2013
IT LOOKS LIKE THE IFR/LIFR CIGS/VSBY WILL LIFT NORTHEAST INTO
NCNTL NEBRASKA THIS AFTERNOON. FOR TONIGHT WE ARE EXPECTING A
RETURN TO IFR/LIFR...MAINLY AFTER 06Z AND THE AREA AFFECTED WOULD
BE FROM KIML NORTHEAST THROUGH KVTN. THE CONCERN IS FOG
DEVELOPMENT WHICH COULD IN SOME AREAS BECOME DENSE ACCORDING TO
THE GUIDANCE WHICH HAS MODERATE SKILL IN THESE TYPES OF EVENTS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
402 AM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT MON JUL 29 2013
TODAY...MULTIPLE MODES OF ATMOSPHERIC UNREST ARE OPERATING ACROSS
THE FCST AREA THIS MORNING AND ARE EXPECTED TO CONTINUE THROUGH
THIS EVENING. STRATUS...FOG...DRIZZLE...SHOWERS PRODUCING DECENT
RAINFALL IN A WARM CLOUD PROCESS ARE OPERATING ACROSS SWRN NEB
THROUGH NCNTL NEBRASKA THIS MORNING. THIS AREA OF WEATHER IS
EXPECTED TO SHIFT EAST THIS MORNING AND COVER AREAS ALONG AND
EAST OF HIGHWAY 183 THIS AFTERNOON. IT IS BELIEVED THAT THE
SHOWERS AND DRIZZLE/FOG SHOULD EXIT BY 18Z AS THIS IS BEING
DRIVEN BY MOISTURE TRANSPORT AT THE 315K SFC AND ACCORDING TO THE
RAP...THIS TRANSPORT SHOULD WEAKEN THIS MORNING.
THE ONGOING MCS ACROSS NWRN NEB IS EXPECTED TO DECAY BY 12Z AS
RADAR SUGGESTS AN OCCLUSION PROCESS IS UNDERWAY ACROSS FAR SWRN
SD. ALSO THE RAP SHOWS MOISTURE TRANSPORT ON THE 315K SFC WILL
WEAKEN.
TEMPERATURES TODAY RANGE FROM 60S ACROSS THE EAST UNDER A BLANKET
OF STRATUS TO 80S ACROSS WRN NEB WHERE IT IS BELIEVED SKIES WILL
CLEAR. THE RAP MODEL SHOWS 750MB CAPE INCREASING TO AROUND 1000
J/KG AND THE NAM THEN SHOWS THE ATM DESTABILIZING ACROSS SWRN AND
WRN NEB LATE THIS AFTERNOON. DOWN DRAFT CAPE NEAR 1000 J/KG COULD
SUPPORT A FEW STORMS WITH GUSTY WINDS...MAINLY THIS EVENING AS
THE STORMS ARE EXPECTED TO ORIGINATE ACROSS THE CYS DIVIDE AND
PARTS OF NERN COLO AND MOVE INTO THE FCST LATE THIS AFTN OR EARLY
EVENING.
TONIGHT...SCATTERED TSTMS ARE EXPECTED TO REMAIN WEST OF HIGHWAY
83 AND MAINLY ALONG AND WEST OF HIGHWAY 61. THE NAM SHOWS THESE
STORMS WEAKENING/DISSIPATING BY 03Z. A WEAK MOSTLY OUTFLOW DRIVEN
COLD FRONT IS EXPECTED TO DRAPE FROM KOGA TO KVTN IN THE WAKE OF
THE STORMS AND LOW LEVEL MOISTURE EAST OF THE FRONT APPEARS
LIKELY TO PRODUCE ANOTHER ROUND OF STRATUS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 400 AM CDT MON JUL 29 2013
UPPER LEVEL RIDGE IS GENERALLY ACROSS THE 4 CORNERS REGION...AND
WILL BUILD EAST TOWARDS THE WEEKEND. MEANWHILE AN UPPER LEVEL
TROUGH/LOW WILL PUSH ACROSS CANADA MID WEEK...WITH THE LOW
REACHING THE SRN PART OF HUDSON BAY BY THE WEEKEND. OVER THE HIGH
PLAINS FLOW WILL BE NORTHWEST THROUGH THE WEEK...WITH A TRANSITION
TO MORE ZONAL BY WEEKEND.
AT THE SFC..COOL CANADIAN HIGH PRESSURE ACROSS THE CENTRAL PLAINS
EARLY...WILL SLOWLY PUSH EAST...WITH A WARM UP EXPECTED. THEN A
COLD FRONT WILL PUSH ACROSS THE AREA WEDNESDAY WITH ANOTHER COOL
DOWN TO END THE WEEK. HIGHS SHOULD RETURN TO THE 80S...NEAR OR
SLIGHTLY BELOW SEASONAL BY MID WEEK...AHEAD OF THE FRONT. BY FRIDAY
AS THE COOLER HIGH PRESSURE PUSHES ACROSS THE CENTRAL
PLAINS...TEMPS TO COOL BACK INTO THE UPPER 70S TO LOWER 80S. AFTER
THE EXTENT OF THE LATEST COOL DOWN...WILL HAVE TO MONITOR CLOSELY
THE COOLER AIR AS A TREND DOWN IN TEMPS IS POSSIBLE.
MODELS IN AGREEMENT WITH AN ACTIVE PATTERN TO CONTINUE THROUGH THE
WEEK WITH SEVERAL DISTURBANCES TO RIDE THE PERIPHERY OF THE RIDGE
AND ACROSS THE AREA. MOISTURE REMAINS DECENT WITH DEW PTS IN THE
UPPER 50S TO LOWER AND MID 60S. WITH EACH QUICK MOVING WAVE EXPECT
SHOWERS AND A FEW THUNDERSTORMS TO BE POSSIBLE.
ON WEDNESDAY...WITH THE PASSAGE OF THE COLD FRONT AND COOLER AIR
ALOFT...THERE COULD BE A FEW STRONG THUNDERSTORMS. TIMING AND
PLACEMENT OF THE BEST INSTABILITY STILL IN QUESTION...AND WILL BE
WATCH OVER THE NEXT COUPLE OF DAYS. THE REST OF THE WEEK WILL
CONTINUE TO SEE A CHANCE FOR SHOWERS AND THUNDERSTORMS ASSOCIATED
WITH EACH PASSING WAVE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1223 AM CDT MON JUL 29 2013
CEILINGS BELOW 1000 FEET AGL ARE LIKELY TO CONTINUE THROUGH THE
NIGHT TONIGHT IN CENTRAL AND SOUTHWEST NEBRASKA...EVEN SPREADING
INTO A LARGE PART OF NORTH CENTRAL NEBRASKA BY 08Z. SOME
PROBABILISTIC MODEL OUTPUT HAS THE CEILING LIFTING ABOVE 1000
FEET BY 17Z...BUT CONTINUING LESS THAN 2000 FEET UNTIL MID-
AFTERNOON. THAT ASSESSMENT SEEMS TO APPLY TO THE LBF TERMINAL.
FOR VTN...THERE IS MORE UNCERTAINTY REGARDING THE EXPECTATION OF
CEILINGS BELOW 1000 FEET. FOR THE AREAS WITH CEILING LOWER THAN
1000 FEET...IT IS NOT LIKELY TO GO BELOW 300 FEET AND WILL MOST
LIKELY STAY AT 600 FEET OR HIGHER IN MUCH OF THE AREA. AREAS OF
BR/FG MAY DEVELOP ALONG THE EDGES OF THE STRATUS BRINGING
VISIBILITY TO LESS THAN 1SM IN AREAS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
950 PM EDT TUE JUL 30 2013
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER OVER SOUTHEAST NORTH CAROLINA
OVERNIGHT AS WEAK HIGH PRESSURE BUILDS INTO THE MID ATLANTIC FROM
THE NORTHWEST. AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE REGION
WEDNESDAY. THIS WILL BE FOLLOWED BY A COLD FRONT THAT SLOWLY CROSSES
THE REGION THURSDAY AND FRIDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 950 PM TUESDAY...
A STATIONARY FRONT REMAINS DRAPED ACROSS EASTERN NC/SC AND EXTENDS
WEST ACROSS GA/AL...WITH WEAK HIGH PRESSURE NOW CENTERED OVER
SOUTHEAST VA. THE FEW SHOWERS AND STORMS IN THE VICINITY OF THE
FRONT HAVE REMAINED NEAR THE COAST THIS EVENING. UPSTREAM...A FAIRLY
PRONOUNCED VORT MAX IS MOVING ACROSS CENTRAL TN...WITH A LARGE AREA
OF MOSTLY STRATIFORM PRECIP OUT AHEAD OF IT...REACHING AS FAR EAST
AS KNOXVILLE. SOME MID/HIGH-LEVEL MOISTENING OVER WESTERN NC CAN BE
SEEN IN THE 00Z KGSO RAOB AND A LARGE VEIL OF CLOUD COVER JUST
REACHING THE WESTERN PIEDMONT. HOWEVER...THERE IS STILL QUITE A BIT
OF DRY AIR BETWEEN 600-800MB AND RAP SOUNDINGS ACTUALLY MAINTAIN
THIS LAYER OF DRY AIR THROUGH THE NIGHT AND INTO WEDNESDAY MORNING.
THE MOST RECENT RUNS OF THE HRRR SUGGEST VERY LIGHT PRECIP OVER THE
WESTERN PIEDMONT AFTER 09-10Z...WHICH MAY END UP JUST BEING
SPRINKLES OR LIGHT RAIN. BASED ON THIS...WILL REMOVE THE MENTION OF
THUNDER FROM THE FORECAST THROUGH MID-MORNING. DEWPOINTS HAVE
SURGED BACK INTO THE UPPER 60S AND LOWER 70S OVER MUCH OF THE
CWA...AND COMBINED WITH INCREASING MID/HIGH CLOUDS...FORECAST LOWS
MOSTLY IN THE UPPER 60S AND LOWER 70S APPEAR ON TRACK.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 PM TUESDAY...
MCS-INDUCED VORT MAX WILL MOVE ACROSS THE AREA ON WEDNESDAY...WITH
CONTINUED MOISTURE RETURN IN STRENGTHENING SOUTHWEST FLOW AHEAD OF
THE MID LEVEL SYSTEM. INSTABILITY WILL BE MARGINAL WITH WEAK
SHEAR...SBCAPE ~500J AND MID LEVEL LAPSE RATES ~5C/KM...BUT THE
VIGOROUS MID LEVEL VORT WILL BE SUPPORTED BY SOME UPPER DIFFLUENCE
WITH A 55-60KT UPPER JET EXITING THE AREA. POP WISE...WILL INTRODUCE
POPS IN THE WEST TOMORROW MORNING...WITH CONVECTION BECOMING LIKELY
ACROSS CENTRAL NC WITH THE TRANSLATION OF THE MID LEVEL SYSTEM AND
DIURNAL INSTABILITY CYCLE. HIGHS WILL BE HAMPERED BY CLOUDINESS...
ESPECIALLY IN THE WEST...WITH LOWER 80S WEST TO SOME UPPER 80S IN
THE EAST WHERE PRECIP WILL BE SLOWER TO ARRIVE.
WE REMAIN IN THE A FAVORABLE MOISTURE ADVECTION REGIME WITH DEEP
SOUTHWEST FLOW TOMORROW NIGHT WITH CYCLONIC FLOW ALOFT. POP CHANCES
WILL REMAIN IN THE HIGH CHANCE TO LIKELY RANGE WITH ONLY SMALL
CHANCES FOR THUNDER GIVEN A LULL IN MID LEVEL DISTURBANCES. MINS
WILL BE MILD GIVEN THE SOUTHERLY FLOW AND CLOUDINESS...68-72.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 250 PM TUESDAY...
OVERALL THE LONG TERM PERIOD WILL CONTINUE TO FEATURE A MEAN TROUGH
ACROSS THE EASTERN CONUS WITH A SERIES OF SHORTWAVES/WEAK FRONTS
PROGRESSING THROUGH THE AREA. THIS SET-UP WILL KEEP THE SUMMER HEAT
AT BAY WHILE PROVIDING PERIODS OF INCREASED SHOWER AND THUNDERSTORM
ACTIVITY.
PRECIP ASSOCIATED WITH THE NEXT UPPER TROUGH/SURFACE FRONT SHOULD BE
ONGOING TO START THE DAY ON THURSDAY. ALTHOUGH THE ACTUAL FRONT WILL
LIKELY NOT MOVE THROUGH THE AREA UNTIL LATE IN THE DAY...THE
PREFRONTAL TROUGH...HEATING (ALTHOUGH EXTENSIVE CLOUD COVER SHOULD
KEEP TEMPS DOWN SOME) AND ANY WEAK DISTURBANCES ALOFT SHOULD PROVIDE
ENOUGH OF A TRIGGER FOR CONVECTION VIRTUALLY ANYWHERE IN THE
FORECAST AREA. THEN AS THE FRONT MOVES THROUGH LATER IN THE DAY AND
INTO THE EVENING HOURS...PRECIP SHOULD TRANSLATE FROM WEST TO EAST.
ALTHOUGH WIDESPREAD SEVERE STORMS ARE NOT EXPECTED...WITH INCREASING
SHEAR AND POCKETS OF HIGHER INSTABILITY (DIFFERENTIAL HEATING FROM
ANY BREAKS IN THE CLOUDS)...AN ISOLATED STRONG TO SEVERE STORM
CANNOT BE RULED OUT. PRECIP SHOULD END FROM WEST TO EAST THURSDAY
NIGHT INTO FRIDAY MORNING.
BY FRIDAY...THE FRONT SHOULD STALL/WASH OUT SOMEWHERE NEAR THE
REGION. OVERALL...THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH PUSHING
IT SOUTH/EAST OF THE FORECAST AREA WHICH WOULD RESULT IN MOSTLY DRY
CONDITIONS FOR CENTRAL NC...WHILE THE GFS HAS SLOWER WITH THE
EASTWARD PROGRESSION (ALTHOUGH THE 12Z RUN OF THE GFS HAS COME MORE
IN LINE WITH THE ECMWF). NEVERTHELESS...GIVEN THE TIME OF THE YEAR
AND THE SIMILARITY TO RECENT EVENTS...WILL MAINTAIN AT LEAST A
MENTION OF PRECIP FOR FRIDAY AND SATURDAY...ESPECIALLY ON FRIDAY AND
MOSTLY ACROSS THE EASTERN/SOUTHERN PORTIONS OF THE FORECAST AREA.
THIS PATTERN WE ARE IN WILL CONTINUE AS YET ANOTHER SYSTEM WILL
APPROACH THE AREA LATE IN THE WEEKEND/EARLY NEXT WEEK (ALTHOUGH
TIMING REMAINS IN QUESTION). LATEST INDICATIONS SHOW PRECIP RAMPING
BACK UP LATE SATURDAY INTO SUNDAY...WITH EARLY NEXT WEEK DRYING OUT
AS THE FRONT SHIFTS/STALLS SOMEWHERE SOUTH/EAST OF THE FORECAST AREA
(ALTHOUGH AS CAN BE EXPECTED THIS FAR OUT...THIS IS TIMING SUBJECT
CHANGE.
TEMPS WILL ULTIMATELY BE DEPENDENT ON THE EXACT TIMING/EXTENT OF ANY
PRECIP THAT OCCURS...BUT SHOULD LARGELY BE NEAR TO SLIGHTLY BELOW
NORMAL THROUGH THE PERIOD.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 PM TUESDAY...
VFR CONDITIONS ARE EXPECTED OVERALL FOR THE 00Z VALID TAF PERIOD.
WHILE SOME GUIDANCE HINTS AT IFR FOG TOWARD KRWI AND KFAY DURING THE
LATE NIGHT AND INTO THE EARLY MORNING HOURS OF WEDNESDAY...SREF
PROBABILITIES OF SUCH CONDITIONS ARE LOW AND HIGHER CLOUDS MOVING IN
FROM THE WEST MAY TEMPER THE THREAT. STILL...THE BETTER CHANCES WITH
RELATIVELY THINNER CLOUDS SHOULD BE TOWARD KFAY AND KRWI...SO FOR
THE 00Z TAF FORECAST MVFR FOG WILL BE INCLUDED FOR PERIODS FROM
ABOUT 09Z TO 13Z AT THOSE TWO SITES.
MOISTENING MID- AND UPPER-LEVELS SHOULD COMPENSATE FOR DRIER
LOW-LEVEL AIR TO ALLOW FOR AT LEAST SOME AREAS OF LIGHT RAIN TO
DEVELOP ALONG AND AHEAD OF A MID-LEVEL DISTURBANCE MOVING ACROSS
CENTRAL NORTH CAROLINA WEDNESDAY. GUIDANCE DIFFERS ON THE POTENTIAL
AND THE TIMING...BUT THE DISTURBANCE IS STRONG ENOUGH...AND THE MID-
AND UPPER-LEVELS MOIST ENOUGH IN GUIDANCE FORECASTS...THAT AREAS OF
LIGHT RAIN SEEM LIKELY SPREADING FROM WEST-TO-EAST ACROSS CENTRAL
NORTH CAROLINA DURING WEDNESDAY. INSTABILITY IS LESS CERTAIN AND
HAVE LEFT OUT THE MENTION OF THUNDER FOR NOW. VARIABLE WINDS
OVERNIGHT BECOME MORE SOUTH TO SOUTHWEST WEDNESDAY.
BEYOND THE 00Z VALID TAF PERIOD...WEDNESDAY NIGHT ADVERSE AVIATION
CONDITIONS INCLUDE THE POTENTIAL FOR SCATTERED THUNDERSTORMS...AND
AREAS OF LOW CLOUDS IN A MOIST AIR MASS. AT LEAST SCATTERED SHOWERS
AND THUNDERSTORMS ARE EXPECTED THURSDAY...BEFORE SUCH CONDITIONS
START TO IMPROVE LATE THURSDAY INTO THURSDAY EVENING. PATCHY SUB-VFR
CONDITIONS IN FOG IS POSSIBLE THURSDAY NIGHT ESPECIALLY TOWARD KFAY
AND KRWI. FOR MUCH OF THE WEEKEND...EXPECT VFR CONDITIONS...WITH
ISOLATED MAINLY LATE DAY CONVECTION PRODUCING ANY ADVERSE AVIATION
CONDITIONS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MLM/DJF
NEAR TERM...BLS
SHORT TERM...MLM
LONG TERM...KRR
AVIATION...MLM/DJF
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
322 PM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT WILL SLIDE OFFSHORE EARLY TUESDAY AND LINGER NEAR
THE COAST INTO WEDNESDAY BEFORE DISSIPATING. HIGH PRESSURE OFFSHORE
WILL DOMINATE LATE IN THE WEEK. ANOTHER COLD FRONT WILL APPROACH FROM
THE NORTHWEST THIS WEEK BEFORE STALLING NEAR OR JUST NORTH OF THE AREA.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 315 PM MONDAY...THUNDERSTORMS HAVE BLOSSOMED THIS AFTERNOON
ACROSS THE REGION IN AREA OF HIGH INSTABILITY WITH SURFACE-BASED
CAPE VALUES IN EXCESS OF 4000 J/KG AND STRONG MOISTURE CONVERGENCE
AHEAD OF COLD FRONTAL BOUNDARY. THE STORMS HAVE BEEN PROLIFIC
LIGHTNING PRODUCERS AND HAVE PRODUCED LOCALIZED HEAVY RAINFALL
AMOUNTS. GOOD AGREEMENT AMONGST THE VARIOUS 4 KM WRF MODELS...THE
HRRR AND THE RAP MODELS THAT THE PRECIPITATION SHOULD DISSIPATE
SHORTLY AFTER DARK WITH LOSS OF HEATING. WILL CARRY A LIKELY POP
ACROSS ROUGHLY THE SOUTHEASTERN THIRD OF THE CWA THROUGH 00Z WITH
HIGH CHANCE ACROSS THE HIGHWAY 17 CORRIDOR AND JUST SLIGHT CHANCE
FAR WEST. WITH SOME SLIGHTLY LOWER DEWPOINTS WORKING INTO THE
REGION...THE FAR NORTHWESTERN COUNTIES MAY NOT SEE ANY
PRECIPITATION THIS EVENING. AFTER DARK...HAVE JUST CHC POPS ALONG
AND EAST OF HIGHWAY 17 WITH NO POPS TO THE WEST. LOW TEMPERATURES
WILL SHOW A SIMILAR GRADIENT WITH UPPER 60S WEST OF HIGHWAY
17...BUT LOWER TO MID 70S TO THE EAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
AS OF 315 PM MONDAY...THE MID-LEVEL TROUGH AXIS SHOULD BE OFFSHORE
BY EARLY TUESDAY ALONG WITH MOST OF THE DEEP MOISTURE AS THE
FRONTAL BOUNDARY MOVES JUST SOUTH OF OUR COAST AND LIKELY STALLS.
THINK ROUGHLY THE NORTHERN TWO-THIRDS OF OUR CWA WILL BE DRY ON
TUESDAY AS UPPER HEIGHTS BUILD IN A ZONAL FLOW ALOFT. DID HANG ON
TO 20 TO 30 PCT POPS ALONG THE SOUTHERN THIRD OF THE AREA TOMORROW
GIVEN THE CLOSE PROXIMITY OF THE FRONT. MAXIMUM TEMPERATURES
SHOULD BE IN THE MIDDLE TO UPPER 80S AREA-WIDE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 245 PM MON...USED A CONSENSUS BLEND THROUGH THE EXTENDED
PERIOD. UPPER PATTERN WILL FEATURE AND AMPLIFYING TROF ALONG THE
EASTERN SEABOARD THROUGH FRIDAY NIGHT. THE TROF WILL SLOWLY LIFT
OUT THIS WEEKEND WITH A ZONAL FLOW RETURNING FOR EARLY NEXT WEEK.
AT THE SURFACE...STATIONARY BOUNDARY TO THE SOUTH TUESDAY NIGHT
WILL LIFT NORTH WEDNESDAY INTO WEDNESDAY NIGHT. A COLD FRONT WILL
SLOWLY APPROACH FROM THE NORTHWEST THIS WEEKEND. HIGHEST RAIN
CHANCES WILL BE IN THE MIDWEEK PERIOD WITH THE WARM FRONT LIFTING
THROUGH AND GOOD LOW LEVEL THETA-E RIDGE SET UP ACROSS THE AREA.
RAIN CHANCES WILL NOT BE AS HIGH FROM LATE WEEK INTO THE WEEKEND
AS THETA-E RIDGE SHIFTS TO THE SOUTH.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 1230 PM MONDAY...STRATUS HAVE BEEN SLOW TO DISSIPATE AT THE
TAF SITES THIS MORNING...BUT HAVE FINALLY DONE SO BY NOON. EXPECT
LARGELY VFR CONDITIONS OUTSIDE OF SCATTERED SHOWERS AND TSTMS
THROUGH THE AFTERNOON AND EVENING...ALTHOUGH HEAVY RAINFALL WILL
REDUCE VSBYS AND CEILINGS TO MVFR AND PERHAPS BRIEFLY IFR AT
TIMES. BOTH PERSISTENCE AND THE 12Z NUMERICAL GUIDANCE INDICATES A
GOOD POSSIBILITY OF FOG LATE TONIGHT...GIVEN HIGH BOUNDARY LAYER
RH AND A WET GROUND IN SPOTS AND WILL FORECAST AT LEAST MVFR FOG
TOWARD TUESDAY MORNING.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 245 PM MON...GENERALLY VFR EXCEPT IN SCATTERED SHOWERS AND
THUNDERSTORMS EACH DAY. LIGHT EAST WINDS WEDNESDAY. SOUTHWEST
THURSDAY THROUGH SATURDAY.
&&
.MARINE...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 325 PM MONDAY...A COLD FRONT IS DRAPED ACROSS THE NORTHERN
TIER OF THE CWA AND WINDS HAVE GONE MORE WNW/NW OVER THE ALBEMARLE
SOUND AND FAR NORTH WHILE OTHER AREAS REMAIN SOUTH. WINDS SHOULD
GRADUALLY VEER TO W/NW LATER TONIGHT AND HAVE INDICATED THAT TREND
IN THE CURRENT MARINE FORECAST. WIND SPEEDS SHOULD REMAIN AOB 15
KNOTS WITH SEAS 2 TO 4 FEET...OUTSIDE OF THIS EVENING`S
CONVECTION. N/NE WINDS EARLY TUESDAY WILL GRADUALLY BECOME MORE
SE/S LATE TUESDAY AS THE FRONT TO THE SOUTH MEANDERS SLOWLY NORTH.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 245 PM MON...FRONTAL BOUNDARY WILL BE JUST SOUTH OF THE
WATERS TUESDAY NIGHT...BUT WILL THEN LIFT NORTH OF THE AREA
WEDNESDAY AND WEDNESDAY NIGHT. A COLD FRONT WILL SLOWLY DRIFT IN
FROM THE NORTHWEST THIS WEEKEND. LIGHT EAST WINDS FORECAST FOR
WEDNESDAY AS THE WARM FRONT LIFTS THROUGH. SOUTHWEST FLOW SETS UP
BEGINNING THURSDAY WITH THE WARM FRONT TO THE NORTH AND THE COLD
FRONT APPROACHING FROM THE NORTHWEST. THE PRESSURE GRADIENT
TIGHTENS UP AS WELL THURSDAY AND FRIDAY WITH 15-20 KNOTS OVER THE
COASTAL WATERS SOUTH OF OREGON INLET AND 10-15 KNOTS ELSEWHERE.
SMALL CRAFT SEAS FORECAST FOR THE OREGON INLET TO OCRACOKE WATERS
OF 4-6 FEET. THE GRADIENT WILL RELAX AS THE FRONT APPROACHES THE
COAST ON SATURDAY WITH WINDS AND SEAS SUBSIDING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...HSA
AVIATION...CTC/HSA
MARINE...CTC/HSA
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
912 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH FROM THE NORTHWEST TODAY...THEN
SLIDE OFFSHORE EARLY TUESDAY. THE FRONT WILL LINGER NEAR THE COAST
INTO WEDNESDAY BEFORE DISSIPATING. HIGH PRESSURE OFFSHORE WILL
DOMINATE LATE IN THE WEEK. ANOTHER COLD FRONT WILL APPROACH FROM
THE NORTHWEST SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 910 AM MONDAY...WIDESPREAD CONVECTION CONTINUES OUT OVER THE
GULF STREAM WITH A SMALL CLUSTER OF SHOWERS OVER THE NORTHERN
OUTER BANKS AND A COUPLE OF ISOLATED SHOWERS OVER PAMLICO COUNTY.
THE NSSL...REGIONAL WRF AND HRRR ALL INDICATE SHOWERS/TSTMS
REFORMING ALONG THE SEA BREEZE AROUND 16-17Z AND MOVING INLAND.
MADE ONLY MINOR ADJUSTMENTS TO THE POPS...BASED ON A CONSENSUS OF
THESE MODELS. WITH TEMPERATURES RUNNING A COUPLE OF DEGREES AHEAD
OF PROJECTIONS...DID BUMP MAX TEMPS UP A DEGREE OR TWO FOR THE
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 220 AM MON...WEAK FRONT WILL CROSS REGION TONIGHT. LIMITED
FORCING ALOFT AND MDLS NOT INDICATING MUCH PRECIP OVER AREA.
INLAND AREAS SEE A DECENT DROP IN PRECIP WTR SO CONT PREV FCST OF
NO POPS INLAND TO SMALL CHC CLOSER TO CST. LOWS WILL RANGE FROM
UPR 60S/AROUND 70 WELL INLAND TO MID 70S BEACHES.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 4 AM MON...A COLD FRONT WILL DISSIPATE ALONG THE COAST TUES
WITH THE SEA BREEZE BECOMING DOMINANT ALONG THE SOUTH COAST IN THE
AFTERNOON. PWATS DROP TO AROUND 1.2" NORTH OF HIGHWAY 70 BUT
REMAIN AROUND 1.7" SOUTHERN SECTIONS...THOUGH THE NAM DOES SHOW
SOME RECOVERY NORTH IN THE AFTERNOON. NEAR ZONAL FLOW ALOFT WITH
LACK OF FORCING WILL LIMIT CONVECTION WITH THE BEST CHANCE
SOUTHERN AREAS ALONG THE SEA BREEZE.
SLY FLOW RETURNS WED BRINGING A RESURGENCE OF PWATS UP TO 2" BY
THE AFTERNOON WHILE THE UPPER LEVEL WILL EXPERIENCE HEIGHT FALLS
IN RESPONSE TO AN UPPER TROUGH DIGGING ACROSS THE MID WEST. A
SERIES OF SHORTWAVE ENERGY WILL MOVE THROUGH FLOW ALOFT WED
THROUGH THU BRINGING THE BEST FORCING AND HIGHEST POPS THROUGH THE
LONG TERM. A COLD FRONT WILL APPROACH THE REGION LATE THU BUT
MODELS STALL THE FRONT TO THE WEST THU NIGHT.
THE UPPER TOUGH AXIS MOVES OFFSHORE THU NIGHT WITH A DRIER AIRMASS
MOVING INTO THE REGION FRI WITH PWATS FORECAST TO DROP TO 1-1.4"
DURING THE AFTERNOON. EXPECT TYPICAL SUMMERTIME PATTERN FRI AND
SAT WITH THE BERMUDA HIGH OFFSHORE AND THE PIEDMONT TROUGH INLAND.
ZONAL TO SLIGHT CYCLONIC FLOW ALOFT WITH NO UPPER LEVEL FORCING
WILL YIELD NEAR TO SLIGHTLY BELOW CLIMO POPS FOR JULY. A COLD
FRONT APPROACHING FROM THE NW AND SHORTWAVE ENERGY ALOFT WILL
BRING BETTER CHANCES FOR CONVECTION SUN.
TEMPS THROUGH THE LONG TERM WILL BE NEAR NORMAL FOR THE MOST PART
WITH HIGHS IN THE UPPER 80S TO AROUND 90 INLAND AND MID 80S ALONG
THE COAST...THOUGH ABUNDANT CLOUD COVER AND GREATER COVERAGE OF
PCPN THU COULD KEEP HIGHS IN THE MID 80S.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 645 AM MON...AREAS OF MVFR/IFR FOG/STRATUS HV DEVELOPED ACROSS
THE AREA. THESE LOW CLOUDS AND FOG SHLD LIFT/DISSIPATE FAIRLY
QUICKLY AFTER SUNRISE WITH VFR BECOMING DOMINANT FROM MID MORN ON.
SOME WDLY SCT TO SCT CONVECTION POSS LATE MORN THRU AFTN...HOWEVER
IMPACTS TO TERMINALS WILL BE BRIEF IF AT ALL. CONT VFR THIS EVENING
THEN WILL AGAIN HAVE THREAT FOR SOME SCT MVFR/IFR STRATUS AND FOG
LATE TONIGHT AS WINDS GO LIGHT TO CALM WITH WEAK FRONT CROSSING.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...A COLD FRONT DISSIPATES ALONG THE SOUTH COAST TUE
WITH DRIER AIR FILTERING IN FROM THE NORTH...BEST CHANCE OF
CONVECTION SOUTHERN SECTIONS ALONG THE SEABREEZE. UPPER TROUGHING
AND A COLD FRONT APPROACHING FROM THE WEST WED AND THU BRINGING
BETTER CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD.
LESSENING CHANCES OF CONVECTION FRI AS THE UPPER TROUGH SLIDES
EAST OF THE REGION WITH THE FRONT STALLING TO THE WEST. PATCHY
LATE NIGHT EARLY MORNING FOG AND STRATUS POSSIBLE EACH DAY THROUGH
THE LONG TERM.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/
AS OF 910 AM MONDAY...NO BIG CHANGES TO THE CURRENT MARINE
FORECAST EXCEPT TO SLIGHTLY INCREASE WINDS TO 10 TO 15 KNOTS OVER
THE SOUNDS AND FAR NORTHERN WATERS BASED ON CURRENT OBSERVATIONS.
SW WINDS OF 15 KNOTS OR LESS SHOULD CONTINUE THROUGH THE DAY. LIGHT
WSW WINDS AHEAD OF THE FRONT IN THE EVENING WILL BECOME LIGHT NNE
LATE. SEAS WILL AVG 2 TO 4 FEET THRU THE PERIOD.
LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 4 AM MON...LIGHT NE WINDS AOB 10 KT EARLY TUE BECOME
ERLY DURING THE AFTERNOON AS A COLD FRONT DISSIPATES ALONG THE
SOUTHERN COASTAL AREAS. SE WINDS AOB 10 KT DOMINATE TUE NIGHT AND
WED WITH HIGH PRES CENTERED OFFSHORE. SW WINDS AROUND 10-15 KT
DEVELOP WED NIGHT AND STRENGTHEN TO 15-20 KT THU AS A TROUGH
LIFTS NORTH THROUGH THE WATERS AND PRES GRADIENTS TIGHTEN BETWEEN
THE BERMUDA HIGH OFFSHORE AND A FRONT APPROACHING FROM THE W. THE
FRONT STALLS W OF THE AREA THU NIGHT/FRI WITH GRADIENTS WEAKENING
SOME WITH SW WINDS MAINLY 10-15 KT BY FRI. SEAS GENERALLY 2-4 FT
THROUGH WED...THEN BUILD TO 3-5 FT WED NIGHT-FRI IN RESPONSE TO
STRONGER SW FLOW.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RF
NEAR TERM...CTC
SHORT TERM...RF
LONG TERM...SK
AVIATION...RF/SK
MARINE...CTC/RF/SK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
630 PM CDT TUE JUL 30 2013
.UPDATE...
ISSUED AT 630 PM CDT TUE JUL 30 2013
THE POTENTIAL STILL EXISTS FOR A BAND OF ISOLATED TO SCATTERED
THUNDERSTORMS OR SHOWERS TO MOVE THROUGH THE REGION OVERNIGHT.
THERE WILL BE FORCING FROM THE UPPER WAVE NEAR THE INTERNATIONAL
BORDER AS WELL AS AN UPPER JET. HOWEVER...INSTABILITY WILL BE VERY
WEAK...WHICH SHOULD LEAD TO LIMITED COVERAGE. THE HRRR AND RAP
SUGGEST PRECIP IS POSSIBLE...BUT WITH 10%-20% COVERAGE. WILL
MAINTAIN THE IDEA OF SCATTERED THUNDERSTORMS. HOPEFULLY...WE
SHOULD HAVE A BETTER IDEA ON THE SITUATION AS THE NEXT UPDATE
APPROACHES.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 332 PM CDT TUE JUL 30 2013
MAIN CHALLENGE FOR THE SHORT TERM REMAINS PCPN CHANCES. MODELS NOT
IN VERY GOOD AGREEMENT ON THE OVERALL DETAILS SO PREFER THE 12Z
TUE SPC WRF FOR PCPN TONIGHT. THE CURRENT AREA OF SHOWERS THAT WAS
ACROSS SOUTH CENTRAL ND HAS FINALLY BEEN THINNING ON ITS NORTHERN
FRINGE. ANOTHER LITTLE PATCH OF ECHOES WENT THRU KDVL AND FELL
APART. SPC DID ISSUE A SEVERE TSTM WATCH FOR PORTIONS OF WESTERN
AND CENTRAL SD. THIS AREA HAS HEATED OUT TODAY AND MLCAPE VALUES
HAVE PUSHED QUITE HIGH. FOR OUR FA THERE HAS BEEN A LOT OF REMNANT
CLOUD COVER WHICH HAS HELD DOWN TEMPS. THE BEST SHORT WAVE IS
DROPPING INTO SOUTHERN CANADA AND THERE ARE A LOT OF SHOWERS
ASSOCIATED WITH IT ACROSS SOUTHERN SASKATCHEWAN AND SOUTHWEST
MANITOBA. SOME OF THESE MAY AFFECT THE NORTHERN FA TONIGHT. THINK
THE SHOWERS/ISOLATED THUNDER APPROACHING THE SOUTHWEST FA WILL
CONTINUE TO DROP SE. SPC WRF AND OTHER MODELS WANT TO KEEP SOME
LOW CHANCES FOR PCPN OVERNIGHT WHILE THE NEW 12Z ECMWF IS
BASICALLY DRY. OVERALL CONFIDENCE IS LOW FOR MUCH PCPN IN OUR FA
TONIGHT BUT HAVE KEPT SOME SCATTERED SHOWERS/TSTMS AROUND TO
BLEND WITH ADJACENT OFFICES. LOW LEVEL JET AND WARM ADVECTION
SHOULD BE SOUTH OF THE FA AS WELL WHICH ALSO FAVORS THE DRIER
FORECAST.
DID GO WITH A DRY FORECAST WED THINKING ANY LINGERING PCPN WOULD
BE EAST OF THE FA. SEVERAL MODELS SHOW A WEAK SHORT WAVE WED NIGHT
DROPPING A LITTLE LIGHT PCPN IN THE NORTHEAST BUT WITH LITTLE
MODEL CONSENSUS LEFT THE FORECAST DRY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 332 PM CDT TUE JUL 30 2013
A LITTLE BIT OF A COLD POOL WILL DROP DOWN INTO THE NORTH/NE FA ON
THU WITH MORE SHORT WAVE ENERGY. SCENARIO IS GOOD FOR SOME MORNING
SHOWERS WITH THE CHANCE OF SOME AFTERNOON RUMBLES OF THUNDER. MOST
OF THIS ENERGY SHOULD MOVE EAST OF THE FA BY FRIDAY WITH SFC HIGH
PRESSURE BUILDING BACK INTO THE AREA.
FOR SUN NIGHT THRU WED AN UPPER RIDGE AND DRY AIRMASS WILL KEEP
THE EARLY PART OF THE PERIOD DRY...BUT THE RIDGE WILL MOVE OFF TO
THE EAST ON MONDAY AND THERE WILL BE INCREASING CHANCES OF TSTMS
MON AFTN INTO THE EVENING AS A WAVE MOVES ACROSS THE NORTHERN
TIER. ACTIVITY SHOULD CONTINUE INTO THROUGH THE DAY ON TUESDAY AND
IMPROVE BY EARLY WED MORNING. DAYTIME HIGHS NEXT WEEK WILL
CONTINUE TO BE BELOW SEASONAL NORMS...WITH MAX TEMPS GENERALLY IN
THE UPPER 70S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 630 PM CDT TUE JUL 30 2013
ANY CIGS EXPECTED TO BE VFR THROUGH THE PERIOD. THUNDER CHANCES
WILL MOVE THROUGH THE REGION OVERNIGHT...BUT COVERAGE IS NOT
EXPECTED TO BE ENOUGH FOR A MENTION IN THE FORECAST. WILL MONITOR
AND AMEND IF NEEDED. BREEZY NORTHWEST WINDS ARE EXPECTED WEDNESDAY
AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...GODON
LONG TERM...GODON/ROGERS
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
338 PM CDT MON JUL 29 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 338 PM CDT MON JUL 29 2013
FORECAST CHALLENGES INCLUDE CONVECTIVE CHANCES TONIGHT THROUGH
TOMORROW NIGHT. GFS/NAM/ECMWF/GEM SYNOPTIC FIELDS IN GOOD OVERALL
AGREEMENT...BUT DIFFER SOMEWHAT WITH THE MESOSCALE DETAILS. WILL
USE THE RAP FOR THE ONGOING CONVECTION ACROSS CENTRAL ND THIS
EVENING AND TONIGHT...SHIFTING TO A MODEL BLEND FOR THE REMAINDER
OF THE SHORT-TERM.
20 UTC REGIONAL RADARS SHOW THE SHOWERS ACROSS NORTHEAST SD HAVE
BARELY MOVED INTO THE SOUTHERN VALLEY WITH PERHAPS A FEW SPRINKLES
FALLING ACROSS THE LAKES COUNTRY OF WEST CENTRAL MN. WILL KEEP 20
TO 30 POPS IN THESE AREAS THROUGH THE EARLY EVENING AFTER WHICH ANY
REMAINING ACTIVITY SHOULD DISSIPATE. IN ADDITION...THE ORIGINAL
LINE OF CONVECTION AHEAD OF THE SURFACE TROUGH THIS MORNING HAS
DISSIPATED AND GIVEN WAY TO A STRONGER LINE NOW STRETCHING FROM
NORTHWEST OF MINOT TO SOUTHWEST OF BISMARCK...MOVING TO THE EAST
AROUND 25 KTS. THESE THUNDERSTORMS ARE ALIGNED ALONG THE SURFACE
BOUNDARY NEAR THE AXIS OF GREATEST INSTABILITY. AS THE SHORT-WAVE
ALOFT PROPAGATES ACROSS EASTERN ND AND NORTHWEST MN THIS EVENING
AND OVERNIGHT...THESE STORMS WILL CONTINUE TO MOVE ACROSS ND/MN.
HOWEVER...INSTABILITY IS WEAK ALONG AND EAST OF THE VALLEY...SO
THE EXTENT TO WHICH THEY HOLD TOGETHER IS IN QUESTION. THE RAP
WITH SUPPORT FROM THE GFS/NAM DISSIPATE THESE STORMS EAST OF THE
VALLEY AND IF THIS VERIFIES...CURRENT POPS MAY BE TOO HIGH. GIVEN
HIGHER INSTABILITY TO THE WEST...SOME THUNDERSTORMS COULD BE STRONG
AND EVEN SEVERE ACROSS THE DEVILS LAKE BASIN. HOWEVER...NO SEVERE
CONVECTION IS EXPECTED ALONG AND EAST OF THE VALLEY.
MUCH OF TUESDAY SHOULD BE DRY AS THE REGION IS BETWEEN WEATHER
SYSTEMS...BUT SHOWER AND THUNDERSTORM CHANCES INCREASE AGAIN LATE
IN THE DAY AND OVERNIGHT AS A STRONG CANADIAN SHORT-WAVE AND
ASSOCIATED COLD FRONT MOVE ACROSS THE FORECAST AREA. THE HIGHEST
INSTABILITY WILL REMAIN ACROSS SD INTO SOUTHWEST MN...BUT MODELS
INDICATE MLCAPE UP TO 1500 J/KG MAINLY ALONG AND SOUTH OF THE I-94
CORRIDOR BY TUESDAY AFTERNOON. WITH THE APPROACHING COLD FRONT AND
50+ KTS OF 0 TO 6 KM BULK SHEAR ASSOCIATED WITH A 60 TO 80 KT 300
HPA JET STREAK...MODELS HINT AT A CONVECTIVE COMPLEX DEVELOPING
SOMEWHERE NEAR THE ND/SD BORDER. SPC DAY 2 CONVECTIVE OUTLOOK
SHOWS A SLIGHT RISK FOR SEVERE CONVECTION IN THIS AREA AND THIS
SEEMS REASONABLE. EXACT PLACEMENT OF ANY COMPLEX THAT DOES DEVELOP
IS UNCERTAIN AS IS THE EASTWARD EXTENT TO THE SEVERE POTENTIAL...
SO SOMETHING TO FINE-TUNE IN THE NEXT FORECAST PACKAGE IF POSSIBLE.
THERMAL RIDGE AXIS MOVES OVERHEAD IN FRONT OF THE COLD FRONT...SO
HIGHS TUESDAY WILL REACH THE UPPER 70S TO NEAR 80 DEGREES.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 338 PM CDT MON JUL 29 2013
WEDNESDAY AND THURSDAY WILL BE DRY WITH SURFACE HIGH PRESSURE
BUILDING ACROSS THE FORECAST AREA. TEMPERATURES WILL BE A BIT
COOLER WITH HIGHS IN THE 70S AND LOWS IN THE 50S. WINDS WILL BE
BREEZY FROM THE NORTHWEST WEDNESDAY BEFORE BECOMING LIGHT ON
THURSDAY AS THE PRESSURE GRADIENT RELAXES.
HIGH PRESSURE WILL REMAIN FROM MANITOBA INTO EASTERN NORTH DAKOTA
FRIDAY INTO SATURDAY KEEPING US DRY WITH TEMPERATURES REMAINING
NEARLY 10 DEGREES BELOW AVERAGE. HIGH PRESSURE MOVES EAST INTO THE
WESTERN GREAT LAKES REGION BY LATE SUNDAY ALLOWING NEXT SHORT WAVE
AND SURFACE LOW TO MOVE INTO THE NORTHERN PLAINS. THIS SYSTEM WILL
GIVE THE RISK OF SHOWERS AND THUNDERSTORMS SUNDAY TO EASTERN NORTH
DAKOTA AND PARTS OF WESTERN MINNESOTA...WHILE EASTERN FCST AREA WILL
REMAIN DRY. WILL GO WITH MOSTLY 30-40 POPS MONDAY AS SYSTEM MOVES
THROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 108 PM CDT MON JUL 29 2013
AFTERNOON DIURNAL CUMULUS FIELD IN NW MN WILL BE AROUND THROUGH
00Z...MOSTLY SCATTERED BUT LOCALLY VFR BROKEN. OTHERWISE
CONSIDERABLE HIGH CLOUDS WILL BE PRESENT INTO TONIGHT AS SURFACE
TROUGH MOVES SLOWLY EAST THRU ERN ND LATE TONIGHT. HRRR 3 KM
INDICATES SHOWERS TO MOVE INTO DVL REGION BY 00Z AND THEN INTO NRN
VALLEY 02-03Z SO TIMED PRECIP INTO DVL-GFK-TVF BASED ON THAT. SOME
GUSTY SOUTH WINDS TO 20-22KTS DVL INTO GFK THIS AFTN...THEN
DIMINISHING TO UNDER 10 KTS TONIGHT. THREAT FOR PRECIP ESP IN SE
ND INTO WCNTRL MN TUESDAY MIDDAY-AFTN BUT NOT INCLUDED IN LATE
PERIODS OF TAFS AT THIS TIME DUE TO TIMING UNCERTAINTIES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/RIDDLE
AVIATION...RIDDLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
108 PM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 108 PM CDT MON JUL 29 2013
SHOWERS ACROSS NORTHEAST SD HAVE MOVED FARTHER NORTH AND EAST THAN
PREVIOUSLY FORECAST...SO ADDED CHANCE POPS ACROSS SOUTHEAST ND
THROUGH MUCH OF THE AFTERNOON. STILL THINK THE MAIN SHOW WILL BE
THE SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND WESTERN ND
ASSOCIATED WITH THE SURFACE TROUGH AND SHORT-WAVE ALOFT. PRIMARY
CONVECTIVE LINE IS NOW APPROACHING RUGBY...SO INCREASED CHANCE
POPS FARTHER EAST ACROSS THE NORTHERN VALLEY THIS AFTERNOON. A
SECONDARY CONVECTIVE LINE HAS DEVELOPED ALONG THE PRIMARY SURFACE
WIND SHIFT FROM ESTEVAN MB TO WILLISTON TO BAKER MT AND THIS TOO
WILL MAKE ITS WAY ACROSS THE STATE THIS AFTERNOON AND EVENING.
ADJUSTED HOURLY TEMPERATURE AND SKY GRIDS TO BLEND WITH LATEST
OBSERVATIONS. OTHERWISE...FORECAST IS IN GOOD SHAPE.
UPDATE ISSUED AT 1027 AM CDT MON JUL 29 2013
TRICKY PRECIPITATION FORECAST TODAY AND TONIGHT. WILL FOLLOW THE
LATEST RAP FOR THE MORNING UPDATE WHICH APPEARS TO BEST REFLECT
CURRENT REALITY. TWO AREAS OF SHOWERS/THUNDERSTORMS TO BE CONCERNED
WITH TODAY. THE FIRST IS AN CLUSTER OF SHOWERS NORTH AND WEST OF
ABERDEEN ALONG THE NOSE OF A 30 KT 850 HPA JET AND MID-LEVEL
MOISTURE GRADIENT. THE SECOND IS A LINE OF SHOWERS AND EMBEDDED
THUNDERSTORMS FROM STANLEY TO NORTHWEST OF DICKINSON ASSOCIATED
WITH THE MAIN SURFACE TROUGH AND SHORT-WAVE ALOFT. THE RAP
SUGGESTS THESE TWO AREAS OF PRECIPITATION WILL CONVERGE WEST OF
THE FORECAST AREA THIS AFTERNOON AND THEN MOVE INTO THE VALLEY IN
SOME FORM LATER THIS EVENING. BEST MIXED LAYER INSTABILITY (UP TO
1500 J/KG) WILL BE CONFINED TO THE DEVILS LAKE BASIN...SO SOME
STRONG TO MARGINALLY SEVERE STORMS ARE POSSIBLE IN THIS AREA. FOR
NOW...NOT CERTAIN ON STORM AREAL COVERAGE...SO WILL KEEP POPS IN
THE CHANCE CATEGORY INCREASING FROM WEST TO EAST LATE THIS
AFTERNOON AND EVENING.
LARGE MID-HIGH LEVEL CLOUD SHIELD HAS DEVELOPED AHEAD OF THE
SURFACE TROUGH AND THIS MAY IMPACT TEMPERATURES TODAY. FOR NOW...
INCREASED SKY GRIDS AND SLOWED THE RISE OF HOURLY TEMPERATURES...
BUT KEPT AFTERNOON HIGHS IN THE MID TO UPPER 70S. DEPENDING ON
EVOLUTION OF CLOUDS...MAY HAVE TO KNOCK THESE VALUES DOWN A FEW
DEGREES AT THE 1 PM FORECAST UPDATE.
UPDATE ISSUED AT 640 AM CDT MON JUL 29 2013
CONVECTION IN NORTH CENTRAL ND ALONG THE CANADIAN BORDER LOOKS
LIKE IT WILL AT MOST CLIP NORTHWESTERN TOWNER COUNTY. THUS...WILL
CONTINUE TO KEEP ONLY MINIMAL POPS IN THE NORTHWESTERN CWA UNTIL
LATER THIS AFTERNOON. MINOR TWEAKS TO TEMPS AND WINDS BUT NO MAJOR
CHANGES.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
CONVECTION CHANCES THROUGHOUT THE PERIOD WILL BE THE PRIMARY
FORECAST CONCERN.
THE MAIN UPPER RIDGE AXIS OVER WESTERN MN WILL CONTINUE TO SHIFT
EASTWARD TODAY AS NEAR ZONAL FLOW SETS IN. CONVECTION HAS BEEN
ONGOING SINCE AROUND MIDNIGHT IN NORTHWESTERN ND. THINK THAT THIS
ACTIVITY WILL START TO DISSIPATE AS IT MOVES FURTHER EAST INTO
STABLE AIR. HOWEVER...WILL KEEP AN EYE ON IT AND MAY MAKE SOME
LAST MINUTE ADJUSTMENTS.
SHORTWAVE OVER ID SHOULD MOVE OUT INTO THE NORTHERN PLAINS TODAY.
SOUTHERLY WINDS WILL BE PICKING UP AS THE SFC TROUGH AXIS MOVES
INTO ND...SO THERE SHOULD BE SOME RETURN FLOW. ON THE OTHER
HAND...MODELS ARE IN PRETTY DECENT AGREEMENT THAT THE BEST
INSTABILITY AXIS WILL REMAIN TO OUR WEST THIS AFTERNOON. THINK
THAT SOME PRECIP MAY ENTER THE DEVILS LAKE BASIN THIS
AFTERNOON...BUT THE EASTERN TWO THIRDS OF THE CWA WILL NOT SEE
MUCH UNTIL TONIGHT. AT THIS POINT IT SEEMS THAT STORMS MOVING
THROUGH WILL BE SUB SEVERE.
NEAR ZONAL FLOW CONTINUES INTO TUESDAY...WITH A STRONGER SHORTWAVE
TROUGH MOVING INTO MANITOBA. A SFC TROUGH AXIS WILL SET UP OVER
THE CENTRAL CWA AND COULD BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT. SFC BASED CAPE VALUES WILL BE AROUND 1500 J/KG...AND
DEEP LAYER BULK SHEAR WILL BE AROUND 40 KTS OR SO. THE MAIN COLD
FRONT AND UPPER FORCING DO NOT MOVE IN UNTIL TUESDAY NIGHT THOUGH
SO JUST KEPT POPS IN THE 30 PERCENT RANGE BEFORE 00Z.
AS FOR TEMPERATURES...CONTINUED A SLOW WARMING TREND WITH HIGHS
BACK AROUND 80 DEGREES IN SOME AREAS FOR TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
TUESDAY NIGHT...A COLD FRONT MOVING THROUGH ALONG WITH THE MAIN UPPER
TROUGH DIGGING DOWN OUT OF CANADA SHOULD PROVIDE THE FOCUS FOR
CONTINUED THUNDERSTORM DEVELOPMENT. BUMPED UP POPS A BIT INTO THE
HIGH CHANCE RANGE FOR OVERNIGHT HOURS...WITH A BIT OF PRECIP
LINGERING IN THE SOUTHEAST WEDNESDAY MORNING. WEDNESDAY AND
WEDNESDAY NIGHT SHOULD BE FAIRLY QUIET WITH SFC HIGH PRESSURE
BUILDING IN AND NORTHWESTERLY FLOW ALOFT. TEMPS WILL GET KNOCKED
BACK A BIT INTO THE 70S BEHIND THE COLD FRONT ON WEDNESDAY.
THURSDAY-SUNDAY...
A VERY STAGNANT UPPER FLOW PATTERN IS EXPECTED TO PERSIST THROUGH
THE MAJORITY OF THIS PERIOD. NORTHWEST FLOW ALOFT WILL BE MAINTAINED
ACROSS THE NORTHERN PLAINS IN BETWEEN A BLOCKING UPPER LEVEL RIDGE
ACROSS WESTERN CANADA AND A TROUGH OVER EASTERN CANADA...WITH THE
SUBTROPICAL RIDGE REMAINING ANCHORED ACROSS THE SOUTHERN HIGH
PLAINS. THIS PATTERN WILL KEEP DEEP MOISTURE SOUTH OF THE
REGION...AND PRECIP CHANCES LOW OVERALL...ALTHOUGH A FEW SHOWERS ARE
POSSIBLE WITH ANY WAVES DROPPING OUT OF CANADA.
TEMPS ON THURSDAY MAY APPROACH SEASONAL NORMS IN THE 70S TO NEAR 80.
HOWEVER...OPERATIONAL MODELS SUGGEST A STRONGER WAVE WILL PUSH
THROUGH THURSDAY NIGHT...WITH BROAD SFC HIGH PRESSURE NOSING INTO
THE NORTHERN PLAINS FOR LATE WEEK. A SURGE OF REINFORCING COOLER AIR
AMIDST NORTHERLY LOW-LEVEL FLOW WILL KEEP TEMPS BELOW NORMAL THROUGH
NEXT WEEKEND.
BY LATE NEXT WEEKEND...THE 00Z GFS/ECMWF TEMPORARILY FLATTEN THE
UPPER FLOW AND KICK THE WESTERN US UPPER LOW EASTWARD...WITH THE 00Z
ECMWF A BIT MORE ROBUST WITH MOISTURE RETURN AND PRECIP CHANCES.
CONFIDENCE IN ANY SCENARIO AT THIS RANGE IS LOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 108 PM CDT MON JUL 29 2013
AFTERNOON DIURNAL CUMULUS FIELD IN NW MN WILL BE AROUND THROUGH
00Z...MOSTLY SCATTERED BUT LOCALLY VFR BROKEN. OTHERWISE
CONSIDERABLE HIGH CLOUDS WILL BE PRESENT INTO TONIGHT AS SURFACE
TROUGH MOVES SLOWLY EAST THRU ERN ND LATE TONIGHT. HRRR 3 KM
INDICATES SHOWERS TO MOVE INTO DVL REGION BY 00Z AND THEN INTO NRN
VALLEY 02-03Z SO TIMED PRECIP INTO DVL-GFK-TVF BASED ON THAT. SOME
GUSTY SOUTH WINDS TO 20-22KTS DVL INTO GFK THIS AFTN...THEN
DIMINISHING TO UNDER 10 KTS TONIGHT. THREAT FOR PRECIP ESP IN SE
ND INTO WCNTRL MN TUESDAY MIDDAY-AFTN BUT NOT INCLUDED IN LATE
PERIODS OF TAFS AT THIS TIME DUE TO TIMING UNCERTAINTIES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...JR
LONG TERM...JR/MAKOWSKI
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1106 AM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 1105 AM CDT MON JUL 29 2013
LOCAL RADAR SHOWING AN UPSCALE TREND IN AREAL COVERAGE AND
INTENSITY OF THUNDERSTORMS APPROACHING MINOT. HAVE ADJUSTED POPS
AND WEATHER GRIDS ACCORDINGLY FOR THE NEXT FEW HOURS. LATEST
VISIBLE IMAGERY SHOWS A BRIEF BREAK IN THE CLOUDS WEST IN BETWEEN
SUCCESSIVE SHORTWAVES. ANY CLEARING/HEATING WILL LEAD THE WAY TO
AN INCREASE THREAT FOR STRONG TO SEVERE THUNDERSTORMS BY MID TO
LATE AFTERNOON. WILL CONTINUE TO MONITOR.
UPDATE ISSUED AT 825 AM CDT MON JUL 29 2013
LATEST WATER VAPOR IMAGERY AND LOCAL/REGIONAL RADAR SHOWS A COUPLE
OF SHORTWAVES LINING UP FROM CENTRAL MONTANA INTO CENTRAL NORTH
DAKOTA THIS MORNING. UPPER DIVERGENCE FIELD PER SREF SEEMS TO MESH IN
PRETTY WELL WHERE SHOWERS/THUNDERSTORMS ARE DEVELOPING...ESPECIALLY
OVER THE WEST AND NORTH CENTRAL. THE LATEST HRRR MODEL IS
FORECASTING A LINE OF SHOWERS AND THUNDERSTORMS TO IMPINGE ON OUR
WESTERN BORDER BY 17Z TO 18Z WITH A PROGRESSIVE/EASTWARD MOVEMENT
THIS AFTERNOON INTO SOUTH CENTRAL NORTH DAKOTA. THIS SEEMS
REASONABLE PER UPSTREAM WEATHER IN CENTRAL MONTANA.
FOR THIS MORNINGS UPDATE...BASED ON THE ABOVE...HAVE HAVE BOOSTED
POPS WEST AND NORTH CENTRAL...AND CHANGED WORDING TO AREAL
COVERAGE/SCATTERED...VERSUS UNCERTAINTY. BISMARCK SOUNDING AND
CLOUD COVER OUTSIDE OF THE OFFICE STILL SHOWS A CAP IS IN
PLACE...BUT WITH THE APPROACH OF THE UPSTREAM SHORTWAVES...ENOUGH
COOLING ALOFT WILL ALLOW FOR SCATTERED THUNDERSTORMS THIS
AFTERNOON. THUS HAVE MENTIONED ISOLATED SHOWERS FOR THE MORNING
AND THEN INTRODUCED THUNDER FOR THE AFTERNOON FROM BISMARCK EAST.
UPDATE ISSUED AT 636 AM CDT MON JUL 29 2013
ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT
OBS/TRENDS...OTHERWISE LITTLE CHANGE TO THE GOING FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON JUL 29 2013
THE SHORT RANGE MODELS...INCLUDING THE HIGH RESOLUTION CONVECTIVE
SHORT TERM MODELS...WERE DOING A POOR JOB WITH CONVECTION
OCCURRING AT THE TIME OF THIS WRITING. THIS HAS BEEN THE CASE FOR
THE PAST 24 HOURS AS WELL. THE MODEL GUIDANCE IS REASONABLE...
BASED ON POSITION OF SURFACE LOW TROUGH THROUGH EASTERN MONTANA
AND PLACEMENT AND MOVEMENT OF MID LEVEL DISTURBANCES...IT IS JUST
THAT THE ATMOSPHERE IS NOT COOPERATING AND REACTING AS EXPECTED.
HAVE NOW CASTED THE ONGOING CONVECTION FOR THE NEXT 8 HOURS AND
THEN...IN COLLABORATION WITH NEIGHBORING OFFICES...BLANKETED THE
WEST WITH CHANCE POPS...AND SPREAD THEM EAST THROUGH THE DAY.
AS THE SURFACE TROUGH MOVES INTO THE WESTERN DAKOTAS TODAY...AND
MOISTURE POOLS AROUND IT ON SOUTHEAST SURFACE WINDS AND
INCREASINGLY MOIST (HIGHER DEW POINT) AIR...ENOUGH INSTABILITY
SHOULD BE RELEASED TO TRIGGER DEEP MOIST CONVECTION ACROSS EASTERN
MONTANA AND THE WESTERN DAKOTAS. THIS WILL BE AIDED BY THE NEXT
WEAK MID LEVEL WAVE APPROACHING.
SEVERE WEATHER PARAMETERS ARE LACKING...SO AS FAR AS SEVERE
CONVECTION GOES...NOTHING BUT ISOLATED SEVERE IS ANTICIPATED.
TONIGHT...AS THE SYSTEM MOVES EAST...STORMS WILL END FROM THE
WEST...IN THE EVENING FROM WILLISTON TO DICKINSON...AND BY
MIDNIGHT FROM MINOT TO BISMARCK.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON JUL 29 2013
MEDIUM TO LONG RANGE FORECAST MODELS ARE IN DECENT AGREEMENT FOR
MUCH OF THE LONG TERM FORECAST PERIOD.
MODELS CONTINUE TO INDICATE AN ACTIVE TUESDAY/TUESDAY
NIGHT...ESPECIALLY ALONG TO SOUTH OF INTERSTATE 94 WHERE A LINGERING
SFC BOUNDARY/COLD FRONT WILL COINCIDE WITH DIVERGENT FLOW ALOFT IN
THE RRQ OF AN UPPER LEVEL JET STREAK AND MUCAPE NEARING 1-1.5K J/KG
MID TO LATE AFTERNOON. FARTHER NORTH...A POTENT MID LEVEL TROUGH
WILL SWING EAST ACROSS SOUTH CENTRAL CANADA...INTO LAKE WINNIPEG
LATE AFTERNOON. THIS WILL DRIVE THE SFC COLD FRONT SOUTH INTO SOUTH
DAKOTA BY MID EVENING. BEST CHANCE OF SEVERE WEATHER STILL LOOKS
FROM THE INTERSTATE 94 CORRIDOR COUNTIES SOUTH INTO SOUTH DAKOTA
WITH INSTABILITY TAPERING OFF TO THE NORTH OF THE FRONT. MAIN
QUESTION IS WILL THE MORNING CONVECTION ADVERTISED BY MODELS OVER
EASTERN MONTANA/WESTERN NORTH DAKOTA AND RESULTANT CLOUD COVER BE
ENOUGH TO SHUN THE SEVERE POTENTIAL? OR ARE MODELS PERHAPS
SUGGESTING STRONG TO SEVERE CONVECTION ONGOING TUESDAY MORNING BEING
MAINTAINED THROUGH THE AFTERNOON ALONG THE FRONTAL BOUNDARY?
REGARDLESS...POP WILL BE HIGH GIVEN THE DYNAMICS IN PLACE WITH THE
MAIN QUESTION BEING HOW STRONG WILL THE STORMS BE. WILL MAINTAIN A
HIGH POP FOR MOST LOCATIONS TUESDAY MORNING...AFTERNOON...AND
EVENING...TRENDING DOWN LATE TUESDAY NIGHT/EARLY WED MORNING.
AFTER TUESDAY NIGHT...NORTHWEST FLOW ALOFT DEVELOPS ALONG WITH
SURFACE HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA INTO EASTERN
SOUTH DAKOTA. STABLE AIR ACCOMPANIES THE SFC HIGH SO HAVE REMOVED
ALL MENTION OF PRECIPITATION WED/WED NIGHT...AND TRENDED DOWN
THURSDAY/THURS NIGHT LEAVING A THUNDERSTORM MENTION FAR SOUTH AND
FAR WEST FOR NOW. FOR FRIDAY...PATTERN REMAINS IN PLACE ALTHOUGH WE
DO START TO SEE RETURN FLOW WEST WHERE I HAVE KEPT THUNDERSTORMS IN
THE FORECAST.
LATEST 00Z MODELS DEVELOP A QUASI-ZONAL FLOW OVER THE NORTHERN
PLAINS FOR NEXT WEEKEND WHICH WOULD RESULT IN BETTER CHANCES FOR
MORE WIDESPREAD SHOWERS/THUNDERSTORMS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1105 AM CDT MON JUL 29 2013
MAINLY VFR CIGS/VSBYS OUTSIDE OF ANY THUNDERSTORMS. SCATTERED
SHOWERS AND THUNDERSTORMS WILL BE COMMON THROUGH THE AFTERNOON AND
EARLY EVENING. HAVE INSERTED PREDOMINANT THUNDERSTORM CONDITIONS
WHERE CONFIDENCE WAS HIGHER...AT KMOT/KISN/KDIK/KBIS. WILL
CONTINUE WITH THE VCTS AT KJMS UNTIL THE COVERAGE GETS CLOSER AND
CONFIDENCE IS HIGHER TO MENTION PREDOMINANT. EXPECT MVFR TO POSSIBLE
IFR CIGS/VSBYS IN THE STRONGER THUNDERSTORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JPM
LONG TERM...NH
AVIATION...KS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1027 AM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 1027 AM CDT MON JUL 29 2013
TRICKY PRECIPITATION FORECAST TODAY AND TONIGHT. WILL FOLLOW THE
LATEST RAP FOR THE MORNING UPDATE WHICH APPEARS TO BEST REFLECT
CURRENT REALITY. TWO AREAS OF SHOWERS/THUNDERSTORMS TO BE CONCERNED
WITH TODAY. THE FIRST IS AN CLUSTER OF SHOWERS NORTH AND WEST OF
ABERDEEN ALONG THE NOSE OF A 30 KT 850 HPA JET AND MID-LEVEL
MOISTURE GRADIENT. THE SECOND IS A LINE OF SHOWERS AND EMBEDDED
THUNDERSTORMS FROM STANLEY TO NORTHWEST OF DICKINSON ASSOCIATED
WITH THE MAIN SURFACE TROUGH AND SHORT-WAVE ALOFT. THE RAP
SUGGESTS THESE TWO AREAS OF PRECIPITATION WILL CONVERGE WEST OF
THE FORECAST AREA THIS AFTERNOON AND THEN MOVE INTO THE VALLEY IN
SOME FORM LATER THIS EVENING. BEST MIXED LAYER INSTABILITY (UP TO
1500 J/KG) WILL BE CONFINED TO THE DEVILS LAKE BASIN...SO SOME
STRONG TO MARGINALLY SEVERE STORMS ARE POSSIBLE IN THIS AREA. FOR
NOW...NOT CERTAIN ON STORM AREAL COVERAGE...SO WILL KEEP POPS IN
THE CHANCE CATEGORY INCREASING FROM WEST TO EAST LATE THIS
AFTERNOON AND EVENING.
LARGE MID-HIGH LEVEL CLOUD SHIELD HAS DEVELOPED AHEAD OF THE
SURFACE TROUGH AND THIS MAY IMPACT TEMPERATURES TODAY. FOR NOW...
INCREASED SKY GRIDS AND SLOWED THE RISE OF HOURLY TEMPERATURES...
BUT KEPT AFTERNOON HIGHS IN THE MID TO UPPER 70S. DEPENDING ON
EVOLUTION OF CLOUDS...MAY HAVE TO KNOCK THESE VALUES DOWN A FEW
DEGREES AT THE 1 PM FORECAST UPDATE.
UPDATE ISSUED AT 640 AM CDT MON JUL 29 2013
CONVECTION IN NORTH CENTRAL ND ALONG THE CANADIAN BORDER LOOKS
LIKE IT WILL AT MOST CLIP NORTHWESTERN TOWNER COUNTY. THUS...WILL
CONTINUE TO KEEP ONLY MINIMAL POPS IN THE NORTHWESTERN CWA UNTIL
LATER THIS AFTERNOON. MINOR TWEAKS TO TEMPS AND WINDS BUT NO MAJOR
CHANGES.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
CONVECTION CHANCES THROUGHOUT THE PERIOD WILL BE THE PRIMARY
FORECAST CONCERN.
THE MAIN UPPER RIDGE AXIS OVER WESTERN MN WILL CONTINUE TO SHIFT
EASTWARD TODAY AS NEAR ZONAL FLOW SETS IN. CONVECTION HAS BEEN
ONGOING SINCE AROUND MIDNIGHT IN NORTHWESTERN ND. THINK THAT THIS
ACTIVITY WILL START TO DISSIPATE AS IT MOVES FURTHER EAST INTO
STABLE AIR. HOWEVER...WILL KEEP AN EYE ON IT AND MAY MAKE SOME
LAST MINUTE ADJUSTMENTS.
SHORTWAVE OVER ID SHOULD MOVE OUT INTO THE NORTHERN PLAINS TODAY.
SOUTHERLY WINDS WILL BE PICKING UP AS THE SFC TROUGH AXIS MOVES
INTO ND...SO THERE SHOULD BE SOME RETURN FLOW. ON THE OTHER
HAND...MODELS ARE IN PRETTY DECENT AGREEMENT THAT THE BEST
INSTABILITY AXIS WILL REMAIN TO OUR WEST THIS AFTERNOON. THINK
THAT SOME PRECIP MAY ENTER THE DEVILS LAKE BASIN THIS
AFTERNOON...BUT THE EASTERN TWO THIRDS OF THE CWA WILL NOT SEE
MUCH UNTIL TONIGHT. AT THIS POINT IT SEEMS THAT STORMS MOVING
THROUGH WILL BE SUB SEVERE.
NEAR ZONAL FLOW CONTINUES INTO TUESDAY...WITH A STRONGER SHORTWAVE
TROUGH MOVING INTO MANITOBA. A SFC TROUGH AXIS WILL SET UP OVER
THE CENTRAL CWA AND COULD BE THE FOCUS FOR THUNDERSTORM
DEVELOPMENT. SFC BASED CAPE VALUES WILL BE AROUND 1500 J/KG...AND
DEEP LAYER BULK SHEAR WILL BE AROUND 40 KTS OR SO. THE MAIN COLD
FRONT AND UPPER FORCING DO NOT MOVE IN UNTIL TUESDAY NIGHT THOUGH
SO JUST KEPT POPS IN THE 30 PERCENT RANGE BEFORE 00Z.
AS FOR TEMPERATURES...CONTINUED A SLOW WARMING TREND WITH HIGHS
BACK AROUND 80 DEGREES IN SOME AREAS FOR TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM CDT MON JUL 29 2013
TUESDAY NIGHT...A COLD FRONT MOVING THROUGH ALONG WITH THE MAIN UPPER
TROUGH DIGGING DOWN OUT OF CANADA SHOULD PROVIDE THE FOCUS FOR
CONTINUED THUNDERSTORM DEVELOPMENT. BUMPED UP POPS A BIT INTO THE
HIGH CHANCE RANGE FOR OVERNIGHT HOURS...WITH A BIT OF PRECIP
LINGERING IN THE SOUTHEAST WEDNESDAY MORNING. WEDNESDAY AND
WEDNESDAY NIGHT SHOULD BE FAIRLY QUIET WITH SFC HIGH PRESSURE
BUILDING IN AND NORTHWESTERLY FLOW ALOFT. TEMPS WILL GET KNOCKED
BACK A BIT INTO THE 70S BEHIND THE COLD FRONT ON WEDNESDAY.
THURSDAY-SUNDAY...
A VERY STAGNANT UPPER FLOW PATTERN IS EXPECTED TO PERSIST THROUGH
THE MAJORITY OF THIS PERIOD. NORTHWEST FLOW ALOFT WILL BE MAINTAINED
ACROSS THE NORTHERN PLAINS IN BETWEEN A BLOCKING UPPER LEVEL RIDGE
ACROSS WESTERN CANADA AND A TROUGH OVER EASTERN CANADA...WITH THE
SUBTROPICAL RIDGE REMAINING ANCHORED ACROSS THE SOUTHERN HIGH
PLAINS. THIS PATTERN WILL KEEP DEEP MOISTURE SOUTH OF THE
REGION...AND PRECIP CHANCES LOW OVERALL...ALTHOUGH A FEW SHOWERS ARE
POSSIBLE WITH ANY WAVES DROPPING OUT OF CANADA.
TEMPS ON THURSDAY MAY APPROACH SEASONAL NORMS IN THE 70S TO NEAR 80.
HOWEVER...OPERATIONAL MODELS SUGGEST A STRONGER WAVE WILL PUSH
THROUGH THURSDAY NIGHT...WITH BROAD SFC HIGH PRESSURE NOSING INTO
THE NORTHERN PLAINS FOR LATE WEEK. A SURGE OF REINFORCING COOLER AIR
AMIDST NORTHERLY LOW-LEVEL FLOW WILL KEEP TEMPS BELOW NORMAL THROUGH
NEXT WEEKEND.
BY LATE NEXT WEEKEND...THE 00Z GFS/ECMWF TEMPORARILY FLATTEN THE
UPPER FLOW AND KICK THE WESTERN US UPPER LOW EASTWARD...WITH THE 00Z
ECMWF A BIT MORE ROBUST WITH MOISTURE RETURN AND PRECIP CHANCES.
CONFIDENCE IN ANY SCENARIO AT THIS RANGE IS LOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 640 AM CDT MON JUL 29 2013
VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD WITH NO BR
FORMING OVER THE EAST THIS MORNING. MID AND HIGH CLOUDS WILL
CONTINUE TO SPREAD OVER THE AREA FROM THE WEST. SHOWERS AND
THUNDERSTORMS WILL BEGIN MOVING INTO THE WESTERN FORECAST AREA
THIS AFTERNOON AND SPREAD EASTWARD OVERNIGHT. HOWEVER...CONFIDENCE
IS NOT HIGH ENOUGH AT SPECIFIC LOCATIONS TO INCLUDE A MENTION
EXCEPT AT KDVL. WINDS WILL SHIFT AROUND TO THE SOUTH AND PICK UP
TO NEAR 10 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...JR
LONG TERM...JR/MAKOWSKI
AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
825 AM CDT MON JUL 29 2013
.UPDATE...
ISSUED AT 825 AM CDT MON JUL 29 2013
LATEST WATER VAPOR IMAGERY AND LOCAL/REGIONAL RADAR SHOWS A COUPLE
OF SHORTWAVES LINING UP FROM CENTRAL MONTANA INTO CENTRAL NORTH
DAKOTA THIS MORNING. UPPER DIVERGENCE FIELD PER SREF SEEMS TO MESH IN
PRETTY WELL WHERE SHOWERS/THUNDERSTORMS ARE DEVELOPING...ESPECIALLY
OVER THE WEST AND NORTH CENTRAL. THE LATEST HRRR MODEL IS
FORECASTING A LINE OF SHOWERS AND THUNDERSTORMS TO IMPINGE ON OUR
WESTERN BORDER BY 17Z TO 18Z WITH A PROGRESSIVE/EASTWARD MOVEMENT
THIS AFTERNOON INTO SOUTH CENTRAL NORTH DAKOTA. THIS SEEMS
REASONABLE PER UPSTREAM WEATHER IN CENTRAL MONTANA.
FOR THIS MORNINGS UPDATE...BASED ON THE ABOVE...HAVE HAVE BOOSTED
POPS WEST AND NORTH CENTRAL...AND CHANGED WORDING TO AREAL
COVERAGE/SCATTERED...VERSUS UNCERTAINTY. BISMARCK SOUNDING AND
CLOUD COVER OUTSIDE OF THE OFFICE STILL SHOWS A CAP IS IN
PLACE...BUT WITH THE APPROACH OF THE UPSTREAM SHORTWAVES...ENOUGH
COOLING ALOFT WILL ALLOW FOR SCATTERED THUNDERSTORMS THIS
AFTERNOON. THUS HAVE MENTIONED ISOLATED SHOWERS FOR THE MORNING
AND THEN INTRODUCED THUNDER FOR THE AFTERNOON FROM BISMARCK EAST.
UPDATE ISSUED AT 636 AM CDT MON JUL 29 2013
ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT
OBS/TRENDS...OTHERWISE LITTLE CHANGE TO THE GOING FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON JUL 29 2013
THE SHORT RANGE MODELS...INCLUDING THE HIGH RESOLUTION CONVECTIVE
SHORT TERM MODELS...WERE DOING A POOR JOB WITH CONVECTION
OCCURRING AT THE TIME OF THIS WRITING. THIS HAS BEEN THE CASE FOR
THE PAST 24 HOURS AS WELL. THE MODEL GUIDANCE IS REASONABLE...
BASED ON POSITION OF SURFACE LOW TROUGH THROUGH EASTERN MONTANA
AND PLACEMENT AND MOVEMENT OF MID LEVEL DISTURBANCES...IT IS JUST
THAT THE ATMOSPHERE IS NOT COOPERATING AND REACTING AS EXPECTED.
HAVE NOW CASTED THE ONGOING CONVECTION FOR THE NEXT 8 HOURS AND
THEN...IN COLLABORATION WITH NEIGHBORING OFFICES...BLANKETED THE
WEST WITH CHANCE POPS...AND SPREAD THEM EAST THROUGH THE DAY.
AS THE SURFACE TROUGH MOVES INTO THE WESTERN DAKOTAS TODAY...AND
MOISTURE POOLS AROUND IT ON SOUTHEAST SURFACE WINDS AND
INCREASINGLY MOIST (HIGHER DEW POINT) AIR...ENOUGH INSTABILITY
SHOULD BE RELEASED TO TRIGGER DEEP MOIST CONVECTION ACROSS EASTERN
MONTANA AND THE WESTERN DAKOTAS. THIS WILL BE AIDED BY THE NEXT
WEAK MID LEVEL WAVE APPROACHING.
SEVERE WEATHER PARAMETERS ARE LACKING...SO AS FAR AS SEVERE
CONVECTION GOES...NOTHING BUT ISOLATED SEVERE IS ANTICIPATED.
TONIGHT...AS THE SYSTEM MOVES EAST...STORMS WILL END FROM THE
WEST...IN THE EVENING FROM WILLISTON TO DICKINSON...AND BY
MIDNIGHT FROM MINOT TO BISMARCK.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON JUL 29 2013
MEDIUM TO LONG RANGE FORECAST MODELS ARE IN DECENT AGREEMENT FOR
MUCH OF THE LONG TERM FORECAST PERIOD.
MODELS CONTINUE TO INDICATE AN ACTIVE TUESDAY/TUESDAY
NIGHT...ESPECIALLY ALONG TO SOUTH OF INTERSTATE 94 WHERE A LINGERING
SFC BOUNDARY/COLD FRONT WILL COINCIDE WITH DIVERGENT FLOW ALOFT IN
THE RRQ OF AN UPPER LEVEL JET STREAK AND MUCAPE NEARING 1-1.5K J/KG
MID TO LATE AFTERNOON. FARTHER NORTH...A POTENT MID LEVEL TROUGH
WILL SWING EAST ACROSS SOUTH CENTRAL CANADA...INTO LAKE WINNIPEG
LATE AFTERNOON. THIS WILL DRIVE THE SFC COLD FRONT SOUTH INTO SOUTH
DAKOTA BY MID EVENING. BEST CHANCE OF SEVERE WEATHER STILL LOOKS
FROM THE INTERSTATE 94 CORRIDOR COUNTIES SOUTH INTO SOUTH DAKOTA
WITH INSTABILITY TAPERING OFF TO THE NORTH OF THE FRONT. MAIN
QUESTION IS WILL THE MORNING CONVECTION ADVERTISED BY MODELS OVER
EASTERN MONTANA/WESTERN NORTH DAKOTA AND RESULTANT CLOUD COVER BE
ENOUGH TO SHUN THE SEVERE POTENTIAL? OR ARE MODELS PERHAPS
SUGGESTING STRONG TO SEVERE CONVECTION ONGOING TUESDAY MORNING BEING
MAINTAINED THROUGH THE AFTERNOON ALONG THE FRONTAL BOUNDARY?
REGARDLESS...POP WILL BE HIGH GIVEN THE DYNAMICS IN PLACE WITH THE
MAIN QUESTION BEING HOW STRONG WILL THE STORMS BE. WILL MAINTAIN A
HIGH POP FOR MOST LOCATIONS TUESDAY MORNING...AFTERNOON...AND
EVENING...TRENDING DOWN LATE TUESDAY NIGHT/EARLY WED MORNING.
AFTER TUESDAY NIGHT...NORTHWEST FLOW ALOFT DEVELOPS ALONG WITH
SURFACE HIGH PRESSURE BUILDING ACROSS NORTH DAKOTA INTO EASTERN
SOUTH DAKOTA. STABLE AIR ACCOMPANIES THE SFC HIGH SO HAVE REMOVED
ALL MENTION OF PRECIPITATION WED/WED NIGHT...AND TRENDED DOWN
THURSDAY/THURS NIGHT LEAVING A THUNDERSTORM MENTION FAR SOUTH AND
FAR WEST FOR NOW. FOR FRIDAY...PATTERN REMAINS IN PLACE ALTHOUGH WE
DO START TO SEE RETURN FLOW WEST WHERE I HAVE KEPT THUNDERSTORMS IN
THE FORECAST.
LATEST 00Z MODELS DEVELOP A QUASI-ZONAL FLOW OVER THE NORTHERN
PLAINS FOR NEXT WEEKEND WHICH WOULD RESULT IN BETTER CHANCES FOR
MORE WIDESPREAD SHOWERS/THUNDERSTORMS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY)
ISSUED AT 430 AM CDT MON JUL 29 2013
NOW CASTING THE CONVECTION UPSTREAM WOULD YIELD NO THUNDERSTORMS AT
ANY TAF SITE THROUGH 29/16Z. AT 29/0910Z THUNDERSTORMS WERE
DEVELOPING THROUGH CENTRAL MONTANA. THEY WILL INCREASE TODAY AND
MOVE INTO NORTH DAKOTA...FROM WEST TO EAST...AS THE NEXT MID LEVEL
WAVE MOVES THROUGH...SUPPORTED AT THE SURFACE BY A TROUGH ALONG
THE MONTANA / DAKOTAS BORDER. SCATTERED STORMS ARE FORECAST AFTER
29/16Z WEST...ADVANCING SLOWLY EAST THROUGH THE DAY...REACHING
KJMS AFTER 29/23Z. EXPECT SOUTHEAST SURFACE WINDS 10 TO 15
KNOTS...GUSTY IN AND NEAR STORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JPM
LONG TERM...NH
AVIATION...JPM
AREA FORECAST DISCUSSION
NWS TULSA OK
959 PM CDT TUE JUL 30 2013
.DISCUSSION...
MOST OF THE AFTERNOON ACTIVITY HAS DISSIPATED WITH THE LOSS OF
DAYTIME HEATING. HOWEVER...ACTIVITY PERSISTS OVER PORTIONS OF
NORTHWEST ARKANSAS...QUITE SIMILAR TO WHAT THE HRRR MODEL WAS
SUGGESTING THIS AFTERNOON. WITH THE WEAK BOUNDARY STALLED OVER THE
REGION IT IS HARD TO RULE OUT OVERNIGHT ACTIVITY. WILL LEAVE THE
SLIGHT CHANCE POPS IN FOR THE OVERNIGHT. THE 00Z NAM STILL
SUPPORTS THE DEVELOPMENT OF FOG ACROSS NORTHEAST OKLAHOMA AND
NORTHWEST ARKANSAS LATE TONIGHT. OVERALL...WILL NOT MAKE MUCH
CHANGE TO THE GOING FORECAST.
LACY
&&
.PREV DISCUSSION... /ISSUED 625 PM CDT TUE JUL 30 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
A FEW SHOWERS OR THUNDERSTORMS WILL LINGER THROUGH 03Z AS WEAK
FRONTAL BOUNDARY PUSHES THROUGH THE AREA OVERNIGHT. MINIMAL
IMPACT AT ANY FORECAST SITE EXPECTED AT THIS TIME. RAINFALL FROM
LAST NIGHT WILL LIKELY LEAD TO MVFR VSBYS AND CEILINGS ACROSS NE
OK AND NW ARKANSAS FROM ABOUT 08-15Z...ESPECIALLY IF SUFFICIENT
CLEARING TAKES PLACE. FRONT SHOULD BE MOSTLY SE OF AREA WED
AFTERNOON.
PREV DISCUSSION... /ISSUED 344 PM CDT TUE JUL 30 2013/
DISCUSSION...
WEAK FRONTAL BOUNDARY CURRENTLY FROM WEST CENTRAL MISSOURI
ON TO CENTRAL OKLAHOMA TO NORTH TEXAS WILL SLIDE SOUTHEAST
TONIGHT TO NEAR INTERSTATE 40 BY WEDNESDAY MORNING. FRONT
CONTINUES SLIDING SOUTH WEDNESDAY TO SOUTH OF RED RIVER.
ALTHOUGH PLENTY OF MOISTURE IS AVAILABLE..UPPER SUPPORT IS
LACKING WHICH TRANSLATES TO CHANCE POPS TONIGHT...MAINLY
BEFORE MIDNIGHT.
UPPER HIGH ANCHORED / CENTERED OVER NEW MEXICO-WEST TEXAS
BRINGS DRY NORTHWEST FLOW WEDNESDAY-THURSDAY. MINOR WAVES
IN THE NORTHWEST FLOW GENERATES LOW CHANCE POPS FRIDAY AND
THE WEEKEND...MAINLY NORTHEAST AREAS.
LOW CHANCE POPS PREVAIL EARLY NEXT WEEK WITH NEAR SEASONAL
(HOT) WEATHER. UNUSUAL...FOR SUMMER...PATTERN FORECAST BY
BOTH ECMWF/GFS NEXT WEEK. SIGNIFICANT HUDSON BAY UPPER LOW
DIVES INTO NORTH CENTRAL STATES...WHILE UPPER RIDGE BUILDS
NORTH INTO BRITISH COLUMBIA YUKON & NORTHWEST TERRITORIES.
GW
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 73 91 72 93 / 20 10 0 0
FSM 74 93 73 95 / 50 20 0 10
MLC 73 94 73 96 / 40 10 0 0
BVO 70 88 68 91 / 20 10 0 0
FYV 70 88 66 90 / 40 10 0 0
BYV 70 87 68 90 / 40 20 0 0
MKO 72 91 72 93 / 40 10 0 0
MIO 71 87 69 90 / 30 10 0 0
F10 73 92 72 94 / 40 10 0 0
HHW 74 95 75 97 / 30 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1005 PM CDT TUE JUL 30 2013
.UPDATE...
ISSUED AT 1000 PM CDT TUE JUL 30 2013
MAINLY DRY RIGHT NOW ACROSS THE CWA...WITH JUST MAYBE SOME SPRINKLES
NORTH OF INTERSTATE 90. CONVECTION EVOLUTION OVERNIGHT REMAINS LOW
CONFIDENCE. HOWEVER IT APPEARS LIKE WE WILL SEE A LULL OVER THE NEXT
FEW HOURS. LATER TONIGHT...SEE PRETTY STRONG THETAE ADVECTION AROUND
800 TO 850 MB...FOCUSED ACROSS THE SOUTHWEST HALF OF THE CWA.
MEANWHILE...BEST UPPER LEVEL FORCING WILL MOVE TO OUR NORTH. LATEST
NAM AND HRRR IN PRETTY GOOD AGREEMENT THAT STORMS CURRENTLY OVER
NORTHERN WYOMING AND SOUTHERN MONTANA WILL MAINTAIN THEMSELVES AS
THEY PUSH EAST TOWARDS OUR AREA. MOST MODEL SOLUTIONS HINT AT AREAS
ALONG AND SOUTH OF INTERSTATE 90 BEING FAVORED BY THIS LATE NIGHT
CONVECTION. THIS WOULD MAKE SENSE GIVEN WHERE THETAE ADVECTION SEEMS
TO WANT TO FOCUS. HOWEVER WITH THE WAVE PASSING TO OUR NORTH...AND
THE RAP AND HRRR BOTH SHOWING ACTIVITY NORTH OF INTERSTATE 90...WILL
JUST KEEP AN EQUAL THREAT OF 40 TO 50 POPS ACROSS THE ENTIRE
CWA...WITH PROGRESSION FROM WEST TO EAST FROM ABOUT 09Z TO 15Z. GIVEN
THE ELEVATED NATURE OF CONVECTION AND LOW INSTABILITY...NOT THINKING
WE SEE ANY SEVERE WEATHER WITH THIS ACTIVITY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 303 PM CDT TUE JUL 30 2013
UPPER DYNAMICS AND RESULTING LIFT SHOULD BE BEST FOR STORMS IN THE
NORTHERN PART OF OUR FORECAST AREA TONIGHT...BUT SOME SIGNIFICANT
CELLS POSSIBLE SOUTHWEST ALSO WHERE BETTER HEATING AND INSTABILITY
WILL COMBINE WITH DECENT MOISTURE. WIND FIELDS ARE NOTHING TO BRAG
ABOUT AT ANY LEVEL AND WILL KEEP TOP POPS NORTH BARELY INTO THE
LIKELY RANGE. WILL BRING THE THREAT INTO THE FAR WEST AT THE START
OF THE EVENING AND MOVE IT SLOWLY EAST. SPC MENTION OF CELLS AND
CLUSTERS SEEMS RIGHT AS IT DOES NOT LOOK LIKE AN MCS ENVIRONMENT.
SEVERE RISK SLIGHT FOR EARLY THIS EVENING OUT WEST ALSO SEEMS RIGHT.
THE SLOW MOVEMENT OF THE THREAT WILL BRING IT INTO THE EXTREME
SOUTHEAST PART OF OUR AREA...SUCH AS TO SLB IN NORTHWEST IA...ABOUT
7 AM CDT/12Z WEDNESDAY. BY THAT TIME THE THREAT WILL BEGIN TO
DECREASE FROM THE NORTHWEST. EXCEPT FOR THE 12Z NAM RUN WHICH
SUGGESTS HANGING ONTO THE THREAT SOUTHEAST WEDNESDAY EVENING...
MODELS HAVE ACTIVITY OUT OF THE DAY BY THE END OF THE WEDNESDAY
DAYTIME PERIOD. SKIES SHOULD GO MOSTLY CLEAR FROM THE NORTHWEST
WEDNESDAY BEHIND THE DECREASE IN SHOWERS AND STORMS.
ASIDE FROM THE SHOWERS AND STORMS...SOLID LOW CLOUDS MAY STAY
ANCHORED SOUTHEAST/FAR EAST INTO MUCH OF TONIGHT...THOUGH THERE ARE
A FEW HOURS OF DAYTIME HEATING LEFT TO BREAK THE CLOUDS UP A LITTLE
MORE. LOW TEMPERATURE SHOULD BE MOSTLY IN THE LOWER 60S TONIGHT.
UPPER 70S NORTHEAST TO LOWER 80S SOUTHWEST LOOK GOOD FOR HIGHS
WEDNESDAY BASED ON LINGERING CLOUD COVER WITH THE CONTINUING MORNING
PRECIPITATION.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 303 PM CDT TUE JUL 30 2013
NOT MUCH ACTIVITY WEDNESDAY NIGHT AS CONVECTIVE THREAT SHIFTS SOUTH
AND EAST AND HIGH PRESSURE BUILDS IN. WITH CLEAR SKIES AND LIGHT
WINDS WILL GO A LITTLE COOLER THAN GUIDANCE...AIMING FOR THE MID TO
UPPER 50S IN MOST SPOTS. NOT OUT OF THE QUESTION FOR A FEW LOW SPOTS
TO TOUCH 50 DEGREES.
A FAIRLY STRONG LITTLE JET MAX SCOOTS THROUGH MINNESOTA ON THURSDAY
AND THURSDAY NIGHT WHICH WILL DRIVE A BOUNDARY SOUTH THURSDAY NIGHT.
TO THE SOUTH AND SOUTHWEST OF THIS JET MAX THE LOW AND MID LEVEL
WIND FIELD ENHANCES WITH A MODERATELY STRONG LOW LEVEL JET AROUND
850MB FOCUSING AROUND THE MISSOURI RIVER FROM ABOUT 0Z FRIDAY
THROUGH 6Z FRIDAY. DEEPER LAYER SHEAR INCREASES A BIT DURING THIS
TIME AS WELL AS THE 700-500MB WINDS TURN MORE NORTHWEST AND
STRENGTHEN A BIT. A SOMEWHAT STABLE AIR MASS WILL LIKELY BE IN PLACE
INITIALLY BUT WITH THE INCREASING LOW LEVEL JET BETTER ELEVATED
INSTABILITY LIKELY TO FEED INTO THE FAR SOUTHERN CWA FROM 0Z TO 6Z
FRIDAY. WHILE THE SEVERE THREAT WILL BE HIGHER TO THE SOUTH AND
SOUTHWEST OF THE CWA THERE WILL STILL BE A THREAT IN THE FAR
SOUTHERN CWA. GOING FORECAST FOR THIS LOOKS PRETTY GOOD AND WILL NOT
STRAY TOO FAR FROM IT. THE FAR NORTHERN CWA MAY HAVE TROUBLE GETTING
ANY ACTIVITY THURSDAY AND THURSDAY NIGHT.
FRIDAY WILL SEE MORE STABLE AIR SETTLE IN FROM THE NORTH AND SHOULD
PROVIDE THE AREA WITH A QUIET AND FAIRLY PLEASANT DAY. HIGHS MAINLY
MID 70S TO LOWER 80S WITH FAIRLY AVERAGE SUMMER TIME HUMIDITY
VALUES.
FOR SATURDAY THROUGH TUESDAY...OVERALL PATTERN CONTINUES TO BE
SOMEWHAT ANOMALOUS FOR THIS TIME OF YEAR WITH A WEAK RIDGE OF HIGH
PRESSURE OVER THE WESTERN HIGH PLAINS AND MODERATE WEST TO NORTHWEST
FLOW ALOFT. THIS KEEPS THE LOWER AND MID LEVEL TEMPERATURES A LITTLE
COOLER THAN NORMAL AS WELL SO SUSPECT THAT TEMPERATURES WILL REMAIN
BELOW NORMAL THROUGH THE PERIOD. IN FACT LOOKING AT THE ECMWF
ENSEMBLE OUTPUT OF 850MB TEMPERATURES THERE IS A REALLY STRONG
SIGNAL TO REMAIN BELOW NORMAL AS 90 TO 95 PERCENT OF THE MEMBERS ARE
COOLER THAN THE THE SEASONAL NORMAL THROUGH ABOUT AUGUST 12. IT DOES
APPEAR THAT THIS PATTERN WILL BE A BIT MORE SUPPORTIVE OF RAIN
CHANCES SO WILL NEED TO INCLUDE SOME MENTION DURING THIS TIME. WILL
AIM FOR THE BEST CHANCE FOR THIS SUNDAY INTO MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 637 PM CDT TUE JUL 30 2013
SCATTERED CONVECTION WILL BE POSSIBLE WEST TO EAST ACROSS THE AREA
THIS EVENING THROUGH WEDNESDAY MIDDAY. WILL KEEP MENTION OF THUNDER
MINIMAL IN THE TAFS AT THIS TIME BECAUSE TIMING/LOCATION OF GREATER
CHANCES DIFFICULT TO PINPOINT...AND INSTABILITY DOES LESSEN AS THE
NIGHT PROGRESSES. WINDS WILL GENERALLY BE VARIABLE AT/BELOW 10KTS
UNTIL A WEAK COLD FRONT PUSHES THROUGH THE REGION WEDNESDAY. HOWEVER
RANDOM OUTFLOW BOUNDARIES FROM CONVECTION COULD BRIEFLY PRODUCE SOME
STRONGER WIND GUSTS UP TO 25-30KTS THIS EVENING. AFTER THE COLD FRONT
PASSES ON WEDNESDAY...WINDS WILL FAVOR NORTHWEST AT 10-15 KTS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHENARD
SHORT TERM...
LONG TERM...08
AVIATION...JH
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1149 PM CDT SUN JUL 28 2013
.UPDATE...
SEE 06Z AVIATION FORECAST BELOW.
&&
.AVIATION...
VFR CONDITIONS SHOULD PREVAIL THROUGH ABOUT SUNRISE ACROSS WEST
CENTRAL TEXAS. MODELS CONTINUE TO SHOW SOME MVFR CIGS DEVELOPING
ACROSS THE SOUTHERN AND EASTERN TERMINALS BY AROUND SUNRISE. IF IT
DOES DEVELOP...SHOULD ONLY LAST A FEW HOURS BEFORE LIFTING AND DISSIPATING.
OTHERWISE...SOUTH AND SOUTHEAST WINDS WILL PREVAIL
TONIGHT...BEFORE INCREASING AND BECOMING GUSTY BY MID MORNING.
&&
.PREV DISCUSSION... /ISSUED 1052 PM CDT SUN JUL 28 2013/
UPDATE...
MINOR CHANGES MADE TO THE FORECAST FOR THE REST OF THE NIGHT.
ISOLATED CONVECTION CONTINUES ACROSS PORTIONS OF THE CONCHO VALLEY
AND NORTH EDWARDS PLATEAU LATE THIS EVENING. WILL KEEP SLIGHT
CHANCE OF SHOWERS AND THUNDERSTORM`S GOING OVERNIGHT FOR ROUGHLY
THE WESTERN HALF OF THE CWA AS A WEAK MID LEVEL DISTURBANCE
AFFECTS THE AREA. LATEST RUC SEEMS TOO AGGRESSIVE WITH QPF
OVERNIGHT WHILE THE HRRR SEEMS MORE REASONABLE. ONLY MINOR CHANGES
WERE MADE TO TEMPS AND DEWPOINTS TO ACCOUNT FOR TRENDS. UPDATED
PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 621 PM CDT SUN JUL 28 2013/
UPDATE...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
AREA RADARS SHOW A FEW SHOWERS ACROSS THE NORTHWEST HILL COUNTRY
AND NORTHERN EDWARDS PLATEAU...BUT NOTHING THAT SEEMS TO BE
IMMINENT FOR THE TERMINAL LOCATIONS AT KJCT/JUNCTION...KBBD/BRADY...AND
KSOA/SONORA. COVERAGE IS ISOLATED AT BEST...BUT SHOULD CONTINUE
FOR AT LEAST THE NEXT FEW HOURS. HAVE INCLUDED A VCSH FOR THE
THOSE SITES AND WILL CONTINUE TO MONITOR. IF THOSE AREAS DO SEE A
SHOWER...THEN GUSTY WINDS AND BRIEF MVFR CIGS WILL BE POSSIBLE.
OTHERWISE...VFR CONDITIONS SHOULD PREVAIL. MODELS SUGGEST SOME
THREAT OF MVFR CIGS AS LOW CLOUDS DEVELOP ACROSS THE SOUTHERN AND
EASTERN AREA BY SUNRISE...AND WILL CONTINUE THE MENTION IN THE
FORECAST FOR NOW.
PREV DISCUSSION... /ISSUED 403 PM CDT SUN JUL 28 2013/
SHORT TERM...
/TONIGHT/
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MOST COUNTIES...
UPPER-LEVEL CIRCULATION...BASED ON THE LATEST WATER VAPOR
LOOP...DOES NOT LOOK AS PROMISING FOR POSSIBLE SHOWERS AND
THUNDERSTORMS TONIGHT. THE NAM AND GFS 500 MB WIND FIELDS INDICATE
A MINOR SHORT-WAVE TROUGH IN THE FLOW OVER SOUTHEASTERN NEW MEXICO
AND WEST TEXAS. THE NAM DEVELOPS THIS TROUGH MORE THAN THE GFS.
UNFORTUNATELY...ANALYSIS OF THE WATER VAPOR LOOP DOES NOT REVEAL
ANY INDICATION OF THIS TROUGH. THE OVERALL FLOW IN THIS AREA IS
NORTHWEST TO SOUTHEAST. THE NAM REALLY DEVELOPS QPF OVER MUCH OF
WEST CENTRAL TEXAS TONIGHT...AND THE MET MOS PRODUCTS PRESENT 60
POPS FOR BOTH ABILENE AND SAN ANGELO TONIGHT. THE MEX HAS ONLY 10
POPS. SO...WITH LOW CONFIDENCE...I DECIDED TO CONTINUE ONLY 20
POPS FOR TONIGHT. BUT...I EXPANDED THE 20 POPS AREA OVER MORE OF
WEST CENTRAL TEXAS TO ALL EXCEPT MAINLY THE NORTHWEST HILL
COUNTRY.
/TOMORROW/
SLIGHT CHANCE POPS CONTINUES MOST LOCATIONS...
THE NAM CONTINUES AN UPPER-LEVEL TROUGH OVER WEST CENTRAL TEXAS
INTO TOMORROW. AGAIN...MY CONFIDENCE IS NOT HIGH. AT LEAST...IT IS
NOT HIGH ENOUGH TO GIVE ABILENE 50 POPS FOR TOMORROW AS THE MET
MOS PRODUCT INDICATES. SO...I WILL CONTINUE WITH ONLY SLIGHT
CHANCE POPS OVER AN ALMOST IDENTICAL AREA TO TONIGHT.
OTHERWISE...AFTERNOON HIGHS TOMORROW IN THE RANGE OF 98 TO AROUND
100...MOST LOCATIONS...LOOK GOOD.
/MONDAY NIGHT/
SLIGHT CHANCE EVENING POPS MAINLY WEST...
IF SHOWERS AND THUNDERSTORMS DO DEVELOP TOMORROW...SOME MAY LINGER
ACROSS MAINLY OUR WEST COUNTIES TOMORROW EVENING. THUS...I DECIDED
TO CONTINUE 20 POPS FOR SOME OF OUR BIG COUNTRY COUNTIES AND A FEW
OTHER WESTERN COUNTIES. OTHERWISE...RAIN CHANCES END AND
TEMPERATURES DROP TO AROUND 75 FOR OVERNIGHT LOWS.
/TUESDAY THROUGH WEDNESDAY.
DRY AND HOT...
MODELS STRENGTHEN THE RIDGE OVER THE REGION. CLOUD COVER WILL
DIMINISH. AFTERNOON HIGHS AND OVERNIGHT LOWS AROUND 100 AND
75...RESPECTIVELY...LOOK LIKELY.
LONG TERM...
/WEDNESDAY NIGHT THROUGH SUNDAY/
DRY CONDITIONS CONTINUE WITH UNSEASONABLY HOT AFTERNOON HIGHS...
MODELS THIS CYCLE CONTINUE HIGH PRESSURE OVER THE REGION. MODELS
INDICATE THE 500 MB HIGH PRESSURE CENTER WILL MEANDER OVER OR NEAR
TEXAS THROUGH NEXT WEEKEND. AFTERNOON HIGHS MAINLY IN THE UPPER
90S TO AROUND 100...WHICH WE ALREADY IN OUR PREVIOUS FORECAST
PACKAGE...STILL LOOKS GOOD. OVERNIGHT LOWS MAY VARY A DEGREE OR
TWO. HOWEVER...NUMBERS CLOSE TO PERSISTENCE...MAINLY LOWER TO MID
70S...LOOK REASONABLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 75 98 76 99 76 / 20 20 5 5 0
SAN ANGELO 75 98 75 100 75 / 20 20 5 5 0
JUNCTION 75 97 75 98 74 / 10 10 5 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1146 PM CDT SUN JUL 28 2013
.AVIATION...
FOR THE 06Z TAFS...NO SIGNIFICANT CHANGES FROM THE 00Z TAFS.
LATE EVENING INFRARED SATELLITE IMAGERY HAS NOT INDICATED A
SIGNIFICANT INCREASE IN MID-LEVEL CLOUDS/MOISTURE RETURN OVER THE
REGION...SO CONFIDENCE IN THE RAP FORECAST SOLUTION MENTIONED
BELOW HAS INCREASED. IN GENERAL...AN ISOLATED SHOWER OR
THUNDERSTORM IS NOT IMPOSSIBLE OVERNIGHT...BUT CHANCES LOOK SMALL
AT THIS TIME. MVFR CIGS ARE STILL EXPECTED TO BUILD OVER KACT
AROUND 12Z.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
FOR THE 00Z TAFS...VFR CONDITIONS ARE EXPECTED AT METROPLEX AREA
TAF SITES WHILE HIGH MVFR CIGS ARE EXPECTED OVER KACT EARLY
TOMORROW MORNING. THERE ARE ALSO SOME LOW PRECIPITATION CHANCES
WORTH MENTIONING HERE IN THE DISCUSSION...BUT NOT IN THE TAFS AT
THIS TIME.
EVENING OBJECTIVE SURFACE ANALYSIS DEPICTS A TROUGH OF LOW-
PRESSURE ORIENTED EAST-WEST ACROSS CENTRAL TEXAS...JUST SOUTH OF
TEMPLE. ANALYSIS ALSO DEPICTS A RELATIVELY TIGHT GRADIENT OF
THETA-E ALONG THIS TROUGH WITH HIGHER THETA-E VALUES LOCATED TO
THE SOUTH OF THE TROUGH. THIS TROUGH LIKELY MARKS WHAT IS LEFT OF
THE STATIONARY BOUNDARY THAT WAS LOCATED NEAR THE TX COAST
YESTERDAY EVENING.
MODELS INDICATE THAT THIS TROUGH AND HIGHER THETA-E AIR WILL MOVE
NORTH OVERNIGHT KEEPING SOME LOW CHANCE OF ISOLATED RAIN SHOWERS
IN PLAY THROUGH THE OVERNIGHT HOURS FOR ALL AREA TAF SITES. NAM
FORECAST SOUNDINGS SEEM TO BE THE MOST AGGRESSIVE WITH MOISTURE
INCREASE AND ASCENT ASSOCIATED WITH THIS NORTHWARD MOVING BOUNDARY
INDICATING SOME CHANCE AT ELEVATED THUNDERSTORMS TONIGHT. THE RAP
SOUNDINGS ARE DRIER AND PROBABLY MORE REPRESENTATIVE OF THIS WEAK
BOUNDARY THAN THE NAM. THEREFORE KEPT MENTION OF PRECIPITATION
OUT OF THE TAFS FOR THE TIME BEING.
MODELS INDICATE THAT THE BOUNDARY BECOMES SO DIFFUSE THAT IT IS
DIFFICULT TO TRACK ANY MORE BY TOMORROW MORNING. THIS SEEMS
REASONABLE WITH NO CONVERGENCE OR LARGE SCALE FLOW TO REINFORCE
THE FRONTAL BOUNDARY. ATTENTION WILL THEN TURN TO AREAS NORTHWEST
OF THE METROPLEX TOMORROW AFTERNOON AS A WEAK UPPER LEVEL
DISTURBANCE MOVES OVERHEAD. AT THIS TIME THE MAIN AREA OF FORCING
FOR ASCENT LOOKS TO REMAIN NORTHWEST OF THE METROPLEX...SO THINK
ALL THUNDERSTORM ACTIVITY WILL TEND TO FOLLOW SUIT.
CAVANAUGH
&&
.UPDATE...
UPDATING FORECAST TO REMOVE POPS FOR THE REST OF THE NIGHT. FWD
SOUNDING SHOWS INVERSION SETTING UP ALREADY...AND IT WILL BE
STRONGER AS THE EVENING COOLS. ALSO TWEAKING SKY/TEMPERATURE GRIDS
JUST A BIT. 84
&&
.PREV DISCUSSION... /ISSUED 310 PM CDT SUN JUL 28 2013/
THE FRONT THAT MOVED THROUGH FRIDAY NIGHT HAS LOST MOST OF ITS
DEFINITION DURING ITS STINT IN CENTRAL TEXAS...BUT THE BROAD AREA
OF ENHANCED MOISTURE THAT POOLED ALONG THE BOUNDARY IS NOW SURGING
NORTHWARD ACROSS NORTH TEXAS. INSTABILITY AND LIFT IS LIMITED...
BUT THE LOW-MID 70 DEWPOINTS COMBINED WITH DIURNAL HEATING HAVE
RESULTED IN A FEW CONVECTIVE SHOWERS IN CENTRAL AND SOUTHEAST
TEXAS. ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS EVENING ACROSS
THE SOUTHERN HALF OF THE CWA WHERE THERE WILL BE A LITTLE BETTER
INSTABILITY...BUT WILL JUST MENTION ISOLATED SHOWERS OVER THE
NORTHERN HALF OF THE AREA THIS EVENING AND TONIGHT. LOWS TONIGHT
WILL BE SEVERAL DEGREES WARMER THAN LAST NIGHT THANKS TO THE
INCREASED MOISTURE...CLOUD COVER AND SOUTHERLY WINDS.
MODELS HAVE ANALYZED A WEAK POCKET OF POTENTIAL VORTICITY OVER
WEST TEXAS AND GUIDANCE /WITH THE EXCEPTION OF THE GFS/ IS IN GOOD
AGREEMENT THAT THIS ENERGY WILL TRACK NORTHEASTWARD AND ACROSS
THE NORTHWEST ZONES TOMORROW. MOISTURE/INSTABILITY WILL BE
SUFFICIENT FOR A FEW SHOWERS/STORMS IN THE NW ZONES MONDAY...AND
ACROSS THE RED RIVER COUNTIES MONDAY EVENING BEFORE THE ENERGY
EXITS THE REGION. THE BRUNT OF THE CONVECTION WILL REMAIN WELL TO
THE NORTH OF THE REGION ACROSS KANSAS AND OKLAHOMA WHERE A STRONG
SHORTWAVE TROUGH WILL TRACK THROUGH THE PLAINS. THIS SHORTWAVE
WILL BE RESPONSIBLE FOR INCREASED SOUTHERLY FLOW TOMORROW WITH
WINDS NEAR 15-20 MPH DURING THE AFTERNOON. HIGH TEMPS WILL
CONTINUE THEIR MODERATING TREND WITH READINGS JUST SHY OF NORMAL.
THE UPPER LEVEL RIDGE WILL STRENGTHEN OVER NEW MEXICO BY TUESDAY
AND WEDNESDAY...WHICH RESULTS IN NORTHWEST TO NORTHERLY FLOW ALOFT
OVER NORTH TEXAS. THIS SHOULD HELP PROPEL A WEAK FRONT IN OKLAHOMA
SOUTHWARD TO THE RED RIVER VALLEY BY WEDNESDAY. MOISTURE AND
INSTABILITY LOOK SUFFICIENT FOR A SLIGHT CHANCE OF SHOWERS/STORMS
ACROSS THE NORTHERN COUNTIES WEDNESDAY AFTERNOON AND EVENING.
AGAIN THE GFS IS THE OUTLIER SOLUTION AND KEEPS THE FRONT WELL TO
THE NORTH...BUT THE GEM/ECMWF REMAIN CONSISTENT IN BRINGING THE
FRONT INTO TEXAS. THE ECMWF IS NOW PUSHING THE FRONT WELL INTO THE
HEART OF THE CWA ON THURSDAY BEFORE DISSIPATING IT. WILL SHOW 10
PERCENT POPS OVER THE ENTIRE AREA ON THURSDAY FOR STRAY CONVECTION
ALONG THE OLD FRONTAL BOUNDARY...BUT WILL NOT MENTION IT IN THE
WORDED FORECAST JUST YET AS THE UPPER HIGH WILL BE INTENSIFYING ON
THURSDAY AND MAY SUPPRESS CONVECTION ALTOGETHER. ALTHOUGH THE
FRONT LOOKS TO ENTER THE CWA MIDWEEK...THERE WILL BE LITTLE COOL
ADVECTION ASSOCIATED WITH IT. IN FACT DIMINISHING SURFACE WINDS
WILL RESULT IN HIGH TEMPS WARMING A DEGREE OR TWO EACH DAY...AND
THE HUMIDITY MAY BE A BIT OPPRESSIVE THURSDAY DUE DEEPER MOISTURE
POOLING ALONG THE DISSIPATING FRONT.
THE UPPER LEVEL RIDGE WILL STRENGTHEN BY LATE WEEK AND TEMPS WILL
CONTINUE TO WARM. FRIDAY LOOKS TO BE THE WARMEST DAY WITH HIGHS
NEAR 100+ IN MOST AREAS. THE CENTER OF THE RIDGE WILL BACK OFF TO
THE SOUTHWEST NEXT WEEKEND WITH PERHAPS A 1-2 DEGREE COOL DOWN.
THE GOOD NEWS IS THAT ANOTHER STRONG BACKDOOR FRONT IS STILL
ADVERTISED IN ABOUT 8 DAYS. THIS LOOKS TO BE THE NEXT SHOT AT MORE
SCATTERED RAINFALL AND COOLER TEMPS.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 77 96 76 97 77 / 10 10 5 5 5
WACO, TX 76 96 76 97 76 / 10 5 5 5 5
PARIS, TX 71 93 72 95 73 / 10 10 20 10 10
DENTON, TX 75 95 75 96 75 / 10 20 10 10 10
MCKINNEY, TX 74 94 74 96 75 / 10 10 10 10 10
DALLAS, TX 78 96 77 98 79 / 10 10 5 5 5
TERRELL, TX 75 95 74 96 75 / 10 5 5 5 5
CORSICANA, TX 75 96 74 96 75 / 10 5 5 5 5
TEMPLE, TX 75 96 74 97 74 / 10 5 5 5 5
MINERAL WELLS, TX 73 96 73 98 75 / 10 20 5 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
749 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM EASTERN NEW YORK TO CENTRAL GEORGIA.
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND WILL REMAIN
ACROSS THE MID ATLANTIC INTO TUESDAY. LOW PRESSURE COMING OUT OF
THE CENTRAL PLAINS WILL APPROACH THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT MONDAY...
MSAS LIFTED INDEX ANALYSIS AND SURFACE PRESSURE FROM 07Z/3AM
SHOWED COLD FRONT FROM JUST EAST OF LYNCHBURG TO JUST SOUTH OF
MARTINSVILLE. ISOLATED SHOWERS WERE JUST EAST OF THE FRONT WITH A
SUBTLE SHORT WAVE COMING THROUGH THE BASE OF THE TROF HELPING
TRIGGER THE PRECIPITATION. LOCAL WRF AND 06Z RUC GUIDANCE LINED UP
WELL WITH THE CURRENT LOCATIONS OF THE PRECIPITATION. BOTH OF
THESE MODELS HAD ALL OF THE PRECIPITATION OUT OF THE FORECAST AREA
BY 10Z/6AM. CLOUDS IN THE EAST WILL TAKE LONGER TO EXIT THE
FORECAST AREA...BUT BY 15Z/11AM...MUCH OF THE REGION WILL BE
MOSTLY SUNNY. SURFACE DEW POINTS HAVE DROPPED INTO THE LOWER 50S
ACROSS WEST VIRGINIA. MODELS HAVE ALL DEW POINTS IN THE FORECAST
AREA DROPPING BELOW 60S DEGREES BY 21Z/5PM. A SLIGHT DOWNSLOPE
WIND WILL BRING THE DRIER AIR ALOFT DOWN TO THE SURFACE EAST OF
THE BLUE RIDGE THIS AFTERNOON. USED A BLEND OF MET/MAV GUIDANCE
FOR AFTERNOON HIGHS. VALLEYS WILL DECOUPLE TONIGHT SO FOLLOWED
COOLER NUMBERS THERE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
AN UPPER LEVEL LOW OVER THE GREAT LAKES THIS MORNING WILL TRAVEL
NORTHEAST INTO THE CANADIAN MARITIMES TUESDAY INTO WEDNESDAY. HIGH
PRESSURE WILL SLIDE EAST ACROSS OUR REGION TUESDAY AND PUSH INTO THE
ATLANTIC WEDNESDAY. COOLER AND DRIER WEATHER EXPECTED TUESDAY. BELOW
NORMAL HIGHS TEMPERATURES WILL RANGE FROM THE LOWER 70S IN THE
MOUNTAINS TO THE MID 80S IN THE PIEDMONT.
MOISTURE OVERRUNS THE RIDGE TUESDAY NIGHT WITH THE CHANCE FOR RAIN
TO RETURN IN THE SOUTHWESTERN PORTIONS OF FORECAST AREA. WITH
ADDITIONAL CLOUD COVER...PLAYED LOW TEMPERATURES CLOSER TO THE
WARMER MOS GUIDANCE TUESDAY NIGHT WITH READINGS THE MID 50S IN THE
MOUNTAINS TO UPPER 60S IN THE SOUTHEAST. LOW TEMPERATURES COULD BE
COOLER ESPECIALLY IN THE NORTHWEST MOUNTAINS IF CLOUD COVER OR
MOISTURE AND SHORTWAVE DOES NOT ARRIVAL OR IS SLOWER. GOOD CHANCE
OF RAIN WEDNESDAY AND WEDNESDAY NIGHT AS AN INSITU WEDGE TAKES
RESIDENCE OVER THE AREA. LEANING TOWARDS A NAM/ECMWF BLEND...RAIN
SHOULD SPREAD NORTHEAST ACROSS OUR REGION WEDNESDAY. THE BEST CHANCE
OF RAIN IS ACROSS THE SOUTHERN BLUE RIDGE MOUNTAINS WITH A
PERSISTENT SOUTHEAST FLOW. WITH THE RAIN KEPT THE ADVERTISED COOLER
HIGHS WEDNESDAY FROM THE LOWER 70S IN THE MOUNTAINS TO LOWER 80S IN
THE PIEDMONT. ALLOWED FOR SOME THUNDERSTORMS IN WEST. USED THE
ENSEMBLE LOWS FOR WEDNESDAY NIGHT FROM THE LOWER 60S IN THE WEST TO
AROUND 70 DEGREES IN THE EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 AM EDT MONDAY...
STRATIFORM RAIN WILL GIVE WAY TO SHOWERS ON THURSDAY...AS A SURFACE
WAVE TRACKS NORTH ALONG A FRONT. THIS FRONT IS EXPECTED TO CLEAR THE
AREA THURSDAY EVENING. SURFACE HIGH PRESSURE AND ZONAL FLOW ALOFT
WILL BRING DRY WEATHER BACK INTO THE REGION THURSDAY NIGHT INTO
SATURDAY. THEN THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
INCREASES ON SUNDAY WITH THE APPROACH OF ANOTHER COLD FRONT.
ON THURSDAY...AS A SURFACE WAVE TRACKS NORTH ALONG A FRONT. THIS
FRONT IS EXPECTED TO CLEAR THE AREA THURSDAY EVENING. SURFACE HIGH
PRESSURE AND ZONAL FLOW ALOFT WILL BRING DRY WEATHER BACK INTO THE
REGION THURSDAY NIGHT INTO SATURDAY. THEN THE NEXT CHANCE FOR
SHOWERS AND THUNDERSTORMS INCREASES ON SUNDAY WITH THE APPROACH OF
ANOTHER COLD FRONT.
TEMPERATURES SHOULD REBOUND TOWARD NORMAL ON THURSDAY AS THE RAIN
MOVES EAST. TEMPERATURES WILL BE AT OR ABOVE NORMAL NEXT WEEKEND
UNTIL THE FRONT PASSES TO THE EAST.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 730 AM EDT MONDAY...
SHALLOW GROUND FOG AT BCB/LWB/BLF WILL DISSIPATE BY 14Z/10AM.
THESE SITES PLUS ROA/LYH/DAN WILL BE VFR FOR THE REST OF THE DAY.
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY...AND INFLUENCE
THE WEATHER PATTERN THROUGH TUESDAY. VFR CONDITIONS ARE EXPECTED
THROUGH TONIGHT. THE EXCEPTION WILL BE VALLEY FOG WITH IFR TO LIFR
VISIBILITIES OVERNIGHT...INCLUDING AT LWB. HIGH CONFIDENCE OF FOG
FORMATION AGAIN TONIGHT AT KLWB.
ON WEDNESDAY...AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA.
EXPECT A RETURN OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS AS EARLY AS LATE TUESDAY NIGHT ACROSS THE WEST.
FOR THURSDAY AND FRIDAY...AN UPPER RIDGE STRETCHES EAST WITH
MOUNTAIN THUNDERSTORMS EXPECTED DURING EACH AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
726 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM EASTERN NEW YORK TO CENTRAL GEORGIA.
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND WILL REMAIN
ACROSS THE MID ATLANTIC INTO TUESDAY. LOW PRESSURE COMING OUT OF
THE CENTRAL PLAINS WILL APPROACH THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT MONDAY...
MSAS LIFTED INDEX ANALYSIS AND SURFACE PRESSURE FROM 07Z/3AM
SHOWED COLD FRONT FROM JUST EAST OF LYNCHBURG TO JUST SOUTH OF
MARTINSVILLE. ISOLATED SHOWERS WERE JUST EAST OF THE FRONT WITH A
SUBTLE SHORT WAVE COMING THROUGH THE BASE OF THE TROF HELPING
TRIGGER THE PRECIPITATION. LOCAL WRF AND 06Z RUC GUIDANCE LINED UP
WELL WITH THE CURRENT LOCATIONS OF THE PRECIPITATION. BOTH OF
THESE MODELS HAD ALL OF THE PRECIPITATION OUT OF THE FORECAST AREA
BY 10Z/6AM. CLOUDS IN THE EAST WILL TAKE LONGER TO EXIT THE
FORECAST AREA...BUT BY 15Z/11AM...MUCH OF THE REGION WILL BE
MOSTLY SUNNY. SURFACE DEW POINTS HAVE DROPPED INTO THE LOWER 50S
ACROSS WEST VIRGINIA. MODELS HAVE ALL DEW POINTS IN THE FORECAST
AREA DROPPING BELOW 60S DEGREES BY 21Z/5PM. A SLIGHT DOWNSLOPE
WIND WILL BRING THE DRIER AIR ALOFT DOWN TO THE SURFACE EAST OF
THE BLUE RIDGE THIS AFTERNOON. USED A BLEND OF MET/MAV GUIDANCE
FOR AFTERNOON HIGHS. VALLEYS WILL DECOUPLE TONIGHT SO FOLLOWED
COOLER NUMBERS THERE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
AN UPPER LEVEL LOW OVER THE GREAT LAKES THIS MORNING WILL TRAVEL
NORTHEAST INTO THE CANADIAN MARITIMES TUESDAY INTO WEDNESDAY. HIGH
PRESSURE WILL SLIDE EAST ACROSS OUR REGION TUESDAY AND PUSH INTO THE
ATLANTIC WEDNESDAY. COOLER AND DRIER WEATHER EXPECTED TUESDAY. BELOW
NORMAL HIGHS TEMPERATURES WILL RANGE FROM THE LOWER 70S IN THE
MOUNTAINS TO THE MID 80S IN THE PIEDMONT.
MOISTURE OVERRUNS THE RIDGE TUESDAY NIGHT WITH THE CHANCE FOR RAIN
TO RETURN IN THE SOUTHWESTERN PORTIONS OF FORECAST AREA. WITH
ADDITIONAL CLOUD COVER...PLAYED LOW TEMPERATURES CLOSER TO THE
WARMER MOS GUIDANCE TUESDAY NIGHT WITH READINGS THE MID 50S IN THE
MOUNTAINS TO UPPER 60S IN THE SOUTHEAST. LOW TEMPERATURES COULD BE
COOLER ESPECIALLY IN THE NORTHWEST MOUNTAINS IF CLOUD COVER OR
MOISTURE AND SHORTWAVE DOES NOT ARRIVAL OR IS SLOWER. GOOD CHANCE
OF RAIN WEDNESDAY AND WEDNESDAY NIGHT AS AN INSITU WEDGE TAKES
RESIDENCE OVER THE AREA. LEANING TOWARDS A NAM/ECMWF BLEND...RAIN
SHOULD SPREAD NORTHEAST ACROSS OUR REGION WEDNESDAY. THE BEST CHANCE
OF RAIN IS ACROSS THE SOUTHERN BLUE RIDGE MOUNTAINS WITH A
PERSISTENT SOUTHEAST FLOW. WITH THE RAIN KEPT THE ADVERTISED COOLER
HIGHS WEDNESDAY FROM THE LOWER 70S IN THE MOUNTAINS TO LOWER 80S IN
THE PIEDMONT. ALLOWED FOR SOME THUNDERSTORMS IN WEST. USED THE
ENSEMBLE LOWS FOR WEDNESDAY NIGHT FROM THE LOWER 60S IN THE WEST TO
AROUND 70 DEGREES IN THE EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 AM EDT MONDAY...
STRATIFORM RAIN WILL GIVE WAY TO SHOWERS ON THURSDAY...AS A SURFACE
WAVE TRACKS NORTH ALONG A FRONT. THIS FRONT IS EXPECTED TO CLEAR THE
AREA THURSDAY EVENING. SURFACE HIGH PRESSURE AND ZONAL FLOW ALOFT
WILL BRING DRY WEATHER BACK INTO THE REGION THURSDAY NIGHT INTO
SATURDAY. THEN THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
INCREASES ON SUNDAY WITH THE APPROACH OF ANOTHER COLD FRONT.
ON THURSDAY...AS A SURFACE WAVE TRACKS NORTH ALONG A FRONT. THIS
FRONT IS EXPECTED TO CLEAR THE AREA THURSDAY EVENING. SURFACE HIGH
PRESSURE AND ZONAL FLOW ALOFT WILL BRING DRY WEATHER BACK INTO THE
REGION THURSDAY NIGHT INTO SATURDAY. THEN THE NEXT CHANCE FOR
SHOWERS AND THUNDERSTORMS INCREASES ON SUNDAY WITH THE APPROACH OF
ANOTHER COLD FRONT.
TEMPERATURES SHOULD REBOUND TOWARD NORMAL ON THURSDAY AS THE RAIN
MOVES EAST. TEMPERATURES WILL BE AT OR ABOVE NORMAL NEXT WEEKEND
UNTIL THE FRONT PASSES TO THE EAST.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 130 AM EDT MONDAY...
SHALLOW GROUND FOG AT BCB/LWB/BLF WILL DISSIPATE BY 14Z/10AM.
THESE SITES PLUS ROA/LYH/DAN WILL BE VFR FOR THE REST OF THE DAY.
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY...AND INFLUENCE
THE WEATHER PATTERN THROUGH TUESDAY. VFR CONDITIONS ARE EXPECTED
THROUGH TONIGHT. THE EXCEPTION WILL BE VALLEY FOG WITH IFR TO LIFR
VISIBILITIES OVERNIGHT...INCLUDING AT LWB. HIGH CONFIDENCE OF FOG
FORMATION AGAIN TONIGHT AT KLWB.
ON WEDNESDAY...AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA.
EXPECT A RETURN OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS AS EARLY AS LATE TUESDAY NIGHT ACROSS THE WEST.
FOR THURSDAY AND FRIDAY...AN UPPER RIDGE STRETCHES EAST WITH
MOUNTAIN THUNDERSTORMS EXPECTED DURING EACH AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/PM
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
433 AM EDT MON JUL 29 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM EASTERN NEW YORK TO CENTRAL GEORGIA.
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND WILL REMAIN
ACROSS THE MID ATLANTIC INTO TUESDAY. LOW PRESSURE COMING OUT OF
THE CENTRAL PLAINS WILL APPROACH THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 415 AM EDT MONDAY...
MSAS LIFTED INDEX ANALYSIS AND SURFACE PRESSURE FROM 07Z/3AM
SHOWED COLD FRONT FROM JUST EAST OF LYNCHBURG TO JUST SOUTH OF
MARTINSVILLE. ISOLATED SHOWERS WERE JUST EAST OF THE FRONT WITH A
SUBTLE SHORT WAVE COMING THROUGH THE BASE OF THE TROF HELPING
TRIGGER THE PRECIPITATION. LOCAL WRF AND 06Z RUC GUIDANCE LINED UP
WELL WITH THE CURRENT LOCATIONS OF THE PRECIPITATION. BOTH OF
THESE MODELS HAD ALL OF THE PRECIPITATION OUT OF THE FORECAST AREA
BY 10Z/6AM. CLOUDS IN THE EAST WILL TAKE LONGER TO EXIT THE
FORCAST AREA...BUT BY 15Z/11AM...MUCH OF THE REGION WILL BE
MOSTLY SUNNY. SURFACE DEW POINTS HAVE DROPPED INTO THE LOWER 50S
ACROSS WEST VIRGINIA. MODELS HAVE ALL DEW POINTS IN THE FORECAST
AREA DROPPING BELOW 60S DEGREES BY 21Z/5PM. A SLIGHT DOWNSLOPE
WIND WILL BRING THE DRIER AIR ALOFT DOWN TO THE SURFACE EAST OF
THE BLUE RIDGE THIS AFTERNOON. USED A BLEND OF MET/MAV GUIDANCE
FOR AFTERNOON HIGHS. VALLEYS WILL DECOUPLE TONIGHT SO FOLLOWED
COOLER NUMBERS THERE FOR OVERNIGHT LOWS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EDT MONDAY...
AN UPPER LEVEL LOW OVER THE GREAT LAKES THIS MORNING WILL TRAVEL
NORTHEAST INTO THE CANADIAN MARITIMES TUESDAY INTO WEDNESDAY. HIGH
PRESSURE WILL SLIDE EAST ACROSS OUR REGION TUESDAY AND PUSH INTO THE
ATLANTIC WEDNESDAY. COOLER AND DRIER WEATHER EXPECTED TUESDAY. BELOW
NORMAL HIGHS TEMPERATURES WILL RANGE FROM THE LOWER 70S IN THE
MOUNTAINS TO THE MID 80S IN THE PIEDMONT.
MOISTURE OVERRUNS THE RIDGE TUESDAY NIGHT WITH THE CHANCE FOR RAIN
TO RETURN IN THE SOUTHWESTERN PORTIONS OF FORECAST AREA. WITH
ADDITIONAL CLOUD COVER...PLAYED LOW TEMPERATURES CLOSER TO THE
WARMER MOS GUIDANCE TUESDAY NIGHT WITH READINGS THE MID 50S IN THE
MOUNTAINS TO UPPER 60S IN THE SOUTHEAST. LOW TEMPERATURES COULD BE
COOLER ESPECIALLY IN THE NORTHWEST MOUNTAINS IF CLOUD COVER OR
MOISTURE AND SHORTWAVE DOES NOT ARRIVAL OR IS SLOWER. GOOD CHANCE
OF RAIN WEDNESDAY AND WEDNESDAY NIGHT AS AN INSITU WEDGE TAKES
RESIDENCE OVER THE AREA. LEANING TOWARDS A NAM/ECMWF BLEND...RAIN
SHOULD SPREAD NORTHEAST ACROSS OUR REGION WEDNESDAY. THE BEST CHANCE
OF RAIN IS ACROSS THE SOUTHERN BLUE RIDGE MOUNTAINS WITH A
PERSISTENT SOUTHEAST FLOW. WITH THE RAIN KEPT THE ADVERTISED COOLER
HIGHS WEDNESDAY FROM THE LOWER 70S IN THE MOUNTAINS TO LOWER 80S IN
THE PIEDMONT. ALLOWED FOR SOME THUNDERSTORMS IN WEST. USED THE
ENSEMBLE LOWS FOR WEDNESDAY NIGHT FROM THE LOWER 60S IN THE WEST TO
AROUND 70 DEGREES IN THE EAST.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 AM EDT MONDAY...
STRATIFORM RAIN WILL GIVE WAY TO SHOWERS ON THURSDAY...AS A SURFACE
WAVE TRACKS NORTH ALONG A FRONT. THIS FRONT IS EXPECTED TO CLEAR THE
AREA THURSDAY EVENING. SURFACE HIGH PRESSURE AND ZONAL FLOW ALOFT
WILL BRING DRY WEATHER BACK INTO THE REGION THURSDAY NIGHT INTO
SATURDAY. THEN THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
INCREASES ON SUNDAY WITH THE APPROACH OF ANOTHER COLD FRONT.
ON THURSDAY...AS A SURFACE WAVE TRACKS NORTH ALONG A FRONT. THIS
FRONT IS EXPECTED TO CLEAR THE AREA THURSDAY EVENING. SURFACE HIGH
PRESSURE AND ZONAL FLOW ALOFT WILL BRING DRY WEATHER BACK INTO THE
REGION THURSDAY NIGHT INTO SATURDAY. THEN THE NEXT CHANCE FOR
SHOWERS AND THUNDERSTORMS INCREASES ON SUNDAY WITH THE APPROACH OF
ANOTHER COLD FRONT.
TEMPERATURES SHOULD REBOUND TOWARD NORMAL ON THURSDAY AS THE RAIN
MOVES EAST. TEMPERATURES WILL BE AT OR ABOVE NORMAL NEXT WEEKEND
UNTIL THE FRONT PASSES TO THE EAST.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AS OF 130 AM EDT MONDAY...
A COLD FRONT WAS NEAR BLUE RIDGE. WIDELY SCT SHRA/TSRA WERE FOUND
MAINLY EAST OF THE FRONTAL BOUNDARY FROM THE VA/NC PIEDMONT
EASTWARD TO THE COAST. EXPECT DAN TO HAVE SHOWERS WITH OCCASIONAL
MVFR VISIBILITIES THROUGH 08Z/4AM.
HIGH POTENTIAL FOR IFR-LIFR FOG AT LWB AND BCB...AND MVFR FOG FOR
DAN AND LYH EARLY THIS MORNING. GROUND IS MOIST FROM RECENT RAIN
AND ALTHOUGH AIR MASS MOVING INTO THE AREA IS DRY...IMMEDIATE SFC
LAYER WILL REMAIN QUITE MOIST AND DECOUPLE FROM BOUNDARY LAYER.
THIS SHOULD ALLOW FOR A SHALLOW LAYER OF GROUND FOG TO FORM AT
THESE TYPICAL SITES. MODERATE CONFIDENCE OF HOW LOW VISIBILITIES
WILL BE. WITH LOWER SURFACE DEW POINTS COMING INTO THE
REGION...TEMPERATURE/DEW POINT SPREAD AT LYH AND DAN MAY NOT
SUPPORT FOG FOR LONG.
SOME STRATOCUMULUS WAS FORMING ALONG THE WESTERN WEDGE OF THE
APPALACHIANS. BLF MAY GO IN AND OUT OF MVFR CEILINGS EARLY THIS
MORNING. HIGHER CONFIDENCE THAT LWB WILL STAY VFR UNTIL THE GROUND
FOG FORMS.
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY...AND INFLUENCE
THE WEATHER PATTERN THROUGH TUESDAY. MAINLY VFR CONDITIONS ARE
EXPECTED THROUGH THIS TIME PERIOD WITH LATE NIGHT AND EARLY
MORNING VALLEY FOG AND IFR VISIBILITIES LIKELY.
ON WEDNESDAY...AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA.
EXPECT A RETURN OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS AS EARLY AS LATE TUESDAY NIGHT ACROSS THE WEST.
FOR THURSDAY AND FRIDAY...AN UPPER RIDGE STRETCHES EAST WITH
MOUNTAIN THUNDERSTORMS EXPECTED DURING THE AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...KK
LONG TERM...RCS
AVIATION...AMS/PM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 PM CDT TUE JUL 30 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 215 PM CDT TUE JUL 30 2013
CURRENTLY AS OF 19Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED SUBTROPICAL
RIDGING OVER THE SOUTHWESTERN U.S....TROUGHING OVER SASKATCHEWAN AND
MANITOBA...AND WEST-NORTHWEST FLOW FROM MONTANA INTO THE FORECAST
AREA. WITHIN THE FLOW...A FEW SHORTWAVES WERE CROSSING NORTH DAKOTA.
CONDITIONS ARE DRY ACROSS THE FORECAST AREA...BUT PLENTY OF STRATUS
OF THE LOW TO MID LEVEL VARIETY EXISTS. THESE CLOUDS HAVE HELD
TEMPERATURES DOWN SOMEWHAT...BUT ENOUGH SUN HAS MADE IT THROUGH WITH
THE 850MB TEMPS BETWEEN 11-13C PER 12Z RAOBS TO BRING READINGS INTO
THE 70S. TO THE WEST...A COLD FRONT WAS PRESENT OVER FAR WESTERN
MN...JUST AHEAD OF THE SHORTWAVES. THE COLD FRONT SO FAR HAS NOT
DONE ANYTHING PRECIPITATION WISE...BUT THERE HAS BEEN CONVECTION
BEHIND THE FRONT OVER SOUTHERN SOUTH DAKOTA.
SYNOPTIC OVERVIEW...
MODELS ARE IN VERY GOOD AGREEMENT DROPPING A PORTION OF THE
TROUGHING OVER SOUTH CENTRAL CANADA THROUGH THE FORECAST AREA
WEDNESDAY AFTERNOON. THIS PORTION OF THE TROUGH...OR SHORTWAVE...IS
OF MOST CONCERN...SINCE IT WILL PUSH THE COLD FRONT TO OUR WEST
ACROSS THE FORECAST AREA. IT APPEARS THE SHORTWAVES CURRENTLY ACROSS
NORTH DAKOTA WILL HEAD EAST TOWARDS UPPER MI.
HAZARDS...
SOME SEVERE WEATHER POTENTIAL WEDNESDAY AFTERNOON GIVEN 0-6 KM SHEAR
VALUES AROUND 40 KT PRESENT WITH A FRONTAL PASSAGE. HOWEVER...THERE
ARE SERIOUS CONCERNS ON AVAILABLE INSTABILITY AS DESCRIBED IN THE
DETAILS BELOW. SHOULD SEVERE WEATHER OCCUR...HAIL WILL BE THE MAIN
CONCERN.
DETAILS...
A LIGHT SOUTHERLY FLOW AHEAD OF THE WESTERN MN COLD FRONT WILL ALLOW
SOME OF THE LOWER CEILING STRATUS AND FOG THAT HAS PRESENT JUST
SOUTH OF THE FORECAST AREA TO COME UP INTO NORTHEAST IOWA AND FAR
SOUTHWEST WISCONSIN TONIGHT. HAVE ADDED SOME FOG MENTION TO THESE
LOCATIONS. OTHERWISE...TONIGHT LOOKS FAIRLY QUIET WITH BASICALLY NO
ISENTROPIC LIFT AND ALL SHORTWAVE FORCING HEADING UP TO THE NORTH.
ONE ITEM OF INTEREST PRESENT IN SOME PAST HRRR RUNS AS WELL AS THE
30.12Z ECMWF AND HIRES-ARW IS A BAND OF SHOWERS FROM NEAR WABASHA
COUNTY TO TAYLOR COUNTY BETWEEN 00-09Z. GIVEN THE 30.17Z HRRR RUN IS
DRY AND AFOREMENTIONED FORCING SIGNALS ARE WEAK TO NONE...HAVE KEPT
THE FORECAST DRY IN THIS AREA. A MIX OF LOW AND HIGHER STRATUS
SHOULD PERSIST THROUGH MUCH OF THE NIGHT...HELPING TO KEEP
TEMPERATURES UP.
ON WEDNESDAY...THE NEXT SHORTWAVE OF FOCUS DROPPING OUT OF SOUTH
CENTRAL CANADA WILL PROVIDE A PERIOD OF DPVA ACROSS THE FORECAST
AREA...ALONG WITH GIVING THE COLD FRONT OVER FAR WESTERN MN A BIGGER
PUSH. THE BIG QUESTIONS ARE BOTH FRONTAL TIMING AND HOW WARM CAN WE
GET PRIOR TO FRONTAL ARRIVAL. ALTHOUGH THERE IS NOW LESS CONCERN
FOR LOW CEILING STRATUS OVER ABOUT THE NORTHWEST 2/3 OF THE FORECAST
AREA...ISENTROPIC LIFT FIELDS SUGGEST A GOOD AMOUNT OF MID/HIGH
CLOUDS WILL OVERSPREAD THE AREA AHEAD OF THE SHORTWAVE AND COLD
FRONT. THE 30.12Z NAM EVEN DEVELOPS SOME LIGHT PRECIPITATION OUT OF
THESE CLOUDS NORTH OF I-90. MAIN COLD FRONTAL TIMING STILL LOOKS TO
BE DURING THE AFTERNOON WHICH IS GOOD...BUT THE AFOREMENTIONED
CLOUDS MAY LIMIT HEATING AND THUS BOTH CAPE AND CONVECTIVE
DEVELOPMENT ON THE FRONT. MODEL CONSENSUS IS TO GET HIGH
TEMPERATURES PRIOR TO FRONTAL ARRIVAL UP INTO THE MID 70S TO AROUND
80...WHICH RESULTS IN ABOUT 500-1000 J/KG OF TALL...THIN CAPE. THE
SKINNY NATURE OF THE CAPE WILL HELP MINIMIZE THE SEVERE WEATHER
POTENTIAL DESPITE FAVORABLE SHEAR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 215 PM CDT TUE JUL 30 2013
SYNOPTIC OVERVIEW...
30.12Z ECMWF/GFS/CANADIAN ALL SUGGEST A REX BLOCK STAYING MOSTLY IN
PLACE OVER WESTERN CANADA INTO THE GULF OF ALASKA...ALONG WITH
TROUGHING OVER SOUTHEAST CANADA INTO THE GREAT LAKES
REGION...THROUGH THE LONG TERM PERIOD. THIS MEANS THE FORECAST AREA
WILL STAY IN COOL...NORTHWEST FLOW WITH SHORTWAVES COMING THROUGH
THAT CAN BE HARD TO TIME. WHETHER OR NOT THESE SHORTWAVES PRODUCE
PRECIPITATION WILL DEPEND ON MOISTURE AVAILABILITY.
WEDNESDAY NIGHT THROUGH FRIDAY...
IN THE WAKE OF WEDNESDAYS COLD FRONTAL PASSAGE...THE 30.12Z NAM
BRINGS SOME PRECIP THROUGH THE SOUTHWESTERN HALF OF THE FORECAST
AREA WEDNESDAY NIGHT. THIS IS A RESULT OF SOME WEAK 305K ISENTROPIC
LIFT AHEAD OF A WEAK SHORTWAVE TRAVERSING IOWA...AS WELL AS BEING IN
THE LEFT EXIT REGION OF A 100 KT JET STREAK. ALL OTHER AVAILABLE
GUIDANCE IS DRY...CONSISTENT TOO WITH THE PREVIOUS FORECAST.
THEREFORE...HAVE KEPT A DRY FORECAST GOING. MODELS HAVE TRENDED
DRIER ON THURSDAY WITH ANY CONVECTIVE FORCING WELL OFF TO OUR NORTH
OR SOUTHWEST. ADDITIONALLY...IT APPEARS THERE SHOULD BE A SURGE OF
DRY AIR ON THURSDAY TO HELP MIX DEWPOINTS DOWN...ALSO FAVORING A
DRIER FORECAST. THURSDAY NIGHT INTO FRIDAY MAY STAND TO HAVE THE
BEST CHANCE FOR PRECIPITATION IN THIS NORTHWEST FLOW...IF YOU
BELIEVE THE NAM. MODELS ARE IN GOOD AGREEMENT DROPPING A SHORTWAVE
THROUGH NORTHERN WI FRIDAY MORNING. THE NAM IS MOST ROBUST IN
GENERATING BOTH LIFT AND QPF FROM THIS SHORTWAVE. HOWEVER...THE
GFS/ECMWF/CANADIAN ARE ALL MUCH DRIER AND SOME EVEN SUGGEST A DRY
FORECAST. THEREFORE...CONFIDENCE IN THE NAM SCENARIO IS QUITE LOW.
DID MAINTAIN A 20 PERCENT CHANCE FOR LATE THURSDAY NIGHT ACROSS THE
FORECAST AREA...AS WELL AS SOUTH OF I-90 ON FRIDAY...IN THE EVENT
THE NAM IS RIGHT. WITH 850MB TEMP ANOMALIES HOVERING IN THAT 0.5-1
STANDARD DEVIATION BELOW NORMAL...TEMPERATURES SHOULD CONTINUE TO
RUN ABOUT 5F DEGREES BELOW NORMAL FOR HIGHS. GENERALLY FOLLOWED A
MODEL GUIDANCE CONSENSUS FOR BOTH HIGHS AND LOWS.
FRIDAY NIGHT THROUGH TUESDAY...
DESPITE A NORTHWEST FLOW DURING THE WEEKEND...CONFIDENCE OF HAVING
IT DRY IS INCREASING. THE REASON IS THAT MODELS HAVE BEEN
CONSISTENTLY SHOWING CANADIAN HIGH PRESSURE BUILDING INTO THE
FORECAST AREA IN THE WAKE OF THAT SHORTWAVE CROSSING NORTHERN WI
FRIDAY MORNING. GIVEN THE CANADIAN SOURCE REGION...THE WEEKEND DOES
LOOK COOL...BUT NOT NEARLY AS COLD AS LAST WEEKEND. 850MB TEMPS DROP
TO 10-12C ON SATURDAY AND 8-11C ON SUNDAY WHICH AT MOST ARE 1-1.5
STANDARD DEVIATIONS BELOW NORMAL. THESE TEMPS STILL SUPPORT HIGHS IN
THE 70S. THE BIGGER QUESTION WILL BE LOWS...WHICH HIGHLY DEPENDS ON
TIMING WHEN THE SURFACE HIGH BUILDS OVERHEAD FOR PRIME RADIATIONAL
COOLING CONDITIONS. LOWS IN THE TYPICAL COLDER SPOTS IN THE 40S ARE
CERTAINLY POSSIBLE.
HEADING INTO EARLY NEXT WEEK...THERE ARE SIGNS IN THE 30.12Z
ECMWF/GFS OF A MORE SIGNIFICANT SHORTWAVE DROPPING THROUGH THE
NORTHWEST FLOW...COMING THROUGH THE FORECAST AREA ON MONDAY. THIS IS
A BIT OF A CHANGE FOR THE ECMWF...BEGINNING TO LEAN MORE TOWARDS
WHAT THE PAST FEW GFS RUNS HAVE SUGGESTED. IN ANY EVENT...CHANCES OF
SHOWERS AND THUNDERSTORMS ARE REQUIRED FOR SUNDAY NIGHT AND MONDAY
TO ACCOUNT FOR THE SHORTWAVE AND ASSOCIATED FORCING. FOR MONDAY
NIGHT AND TUESDAY...CONTINUITY AND MODEL CONSENSUS SUGGESTS HOLDING
ONTO 20-30 PERCENT CHANCES DURING THIS TIME PERIOD. THESE CHANCES
ARE ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE. HOWEVER...NEW
30.12Z GUIDANCE...PARTICULARLY THE ECMWF...SUGGESTING THAT A DRIER
FORECAST MAY BE MORE CORRECT. GIVEN THE UNCERTAINTY BEING IN
NORTHWEST FLOW AND HOW FAR OUT TUESDAY IS IN THE FORECAST...HAVE
LEFT THE CHANCES ALONE FOR NOW. 850MB TEMPS REMAIN BELOW
NORMAL...BETWEEN 10-12C...KEEPING HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE JUL 30 2013
NOT A VERY HIGH CONFIDENCE FORECAST WITH THIS SET OF TAFS. WEAK
RIDGING REMAINS OVER THE AREA WITH LOTS OF MOISTURE TRAPPED IN THE
LOW LEVELS AND THE CONCERN IS WHETHER THIS MOISTURE WILL MANIFEST
ITSELF AS MVFR/IFR CONDITIONS THROUGH THE NIGHT. CURRENTLY SOME
MVFR CEILINGS ALREADY IN PLACE ACROSS NORTHERN IOWA INTO SOUTH
CENTRAL MINNESOTA AND ANY RESTRICTIONS TO VISIBILITY LIMITED TO
SOUTHEAST IOWA AND ILLINOIS. THE 30.18Z NAM AND 30.21Z RAP ARE
INDICATING THE BETTER LOW LEVEL MOISTURE WITH THE BEST CHANCE FOR
SATURATION LOOKS TO STAY SOUTH OF BOTH TAF SITS ACROSS IOWA INTO
ILLINOIS. THIS TREND IS ALSO SEEN IN THE 30.15Z SREF PROBABILITIES
AND 30.20Z HRRR WHICH KEEP THE MVFR/IFR SOUTH OF THE
IOWA/MINNESOTA BORDER. WITH THE MVFR CEILINGS ALREADY VERY CLOSE
TO THE AREA...HAVE NOT TOTALLY BACKED OUT OF THEM OCCURRING...HAVE
JUST PUSHED THE TIMING BACK AND TAKEN THE IFR FROM A CATEGORICAL
OCCURRENCE TO HAVING IT IN A TEMPO GROUP. EITHER WAY...THE
MOISTURE FIELD LOOKS TO GET PUSHED PAST THE AREA WEDNESDAY MORNING
AS A COLD FRONT APPROACHES FROM THE NORTHWEST. A PRE-FRONTAL WIND
SHIFT SHOULD BRING THE WINDS AROUND TO THE WEST AND LIMIT THE
CONVERGENCE ALONG THE FRONT. THE CAPE LOOKS TO BE PRETTY
LIMITED...LESS THAN A 1000 J/KG...SO FOR NOW HAVE ONLY INCLUDED A
VCSH FOR THE AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
235 PM CDT MON JUL 29 2013
.SHORT TERM...(TONIGHT AND TUESDAY)
ISSUED AT 235 PM CDT MON JUL 29 2013
A BIT OF UPPER LEVEL ENERGY WILL WORK WITH THE 850 MB LOW LEVEL
JET/MOISTURE TRANSPORT TO FIRE A SHOWER/THUNDERSTORM COMPLEX IN THE
IA/MO VICINITY TONIGHT...TRACKING IT EAST ON TUES. WHILE THIS
COMPLEX IS EXPECTED TO STAY SOUTH OF THE FORECAST AREA...THERE IS
SOME MEAGER MOISTURE TRANSPORT INTO THE REGION...ALONG WITH A 700 MB
LOW AND WEAK LOW LEVEL TEMPERATURE ADVECTION. MESO MODELS AND 29.12
RUNS OF GFS AND NAM SUGGEST THAT THERE WILL BE ENOUGH CONVERGENCE TO
PRODUCE SCATTERED/ISOLATED SHOWERS LATE TONIGHT THROUGH AT LEAST THE
TUE MORNING. RADAR TRENDS TO THE WEST MIRROR THIS. WILL CONTINUE
SHOWER CHANCES FOR NOW...LITTLE/IF ANY INSTABILTY FOR STORMS.
CHANCES MAY NEED TO BE INCREASED IF THE AREAL COVERAGE LOOKS MORE
WIDESPREAD. AMOUNTS SHOULD BE FAIRLY SMALL FOR THOSE LOCATIONS THAT
RECEIVE SOME RAIN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 235 PM CDT MON JUL 29 2013
500 MB SHORTWAVE TROUGH STILL ON TRACK TO SLIDE WEST-EAST ACROSS
SOUTHERN CANADA OVER THE NEXT COUPLE DAYS...SKIMMING NORTHERN
PORTIONS OF THE GREAT LAKES ON WED. WHILE THE BULK OF THE UPPER
LEVEL FORCING WILL BE TO THE NORTH...THE SYSTEM WILL DRAG A SFC
FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MORE CONSENSUS IN
TIMING OF THE FRONT...WITH THE PREVIOUSLY FAST GFS COMING MORE
INLINE WITH THE NAM AND ECMWF. CONVERGENCE IS SOMEWHAT MEAGER AROUND
THE FRONT...BUT THERE WILL BE ABOUT 1000-1500 J/KG SBCAPE FOR IT TO
TAP...ALTHOUGH BUFKIT SOUNDINGS SHOW ITS FAIRLY SKINNY AND NOT
CONDUCIVE TO STRONG UPDRAFTS. THERE IS GOOD SHEAR OF 35-40 KTS IN
THE 0-6 KM LAYER. IF THE SYSTEM LOOKED MORE DYNAMIC...TIMING WOULD
FAVOR SEVERE WEATHER. AS IT STANDS NOW...SEE STRONG/ISOLATED SEVERE
STORMS MORE LIKELY - AS LONG AS THE INSTABILTY IS THERE. THERE IS
LOW LEVEL WARM AIR ADVECTION/ISENTROPIC UPGLIDE PRE-FRONT...WHICH
COULD RESULT IN SOME CLOUDS/SCATTERED SHOWERS IN THE MORNING. THIS
COULD MUCK UP THE ATMOSPHERE...LEAVING LESS INSTABILTY TO WORK ON.
NOT CLEAR HOW THIS WILL PLAY OUT...BUT THERE WILL BE A GOOD SHOT FOR
SHOWERS/STORMS ON WED...LIKELY MORE WIDESPREAD ACROSS THE NORTH.
ON THU...AREA IS UNDER CYCLONIC FLOW AND THE GFS AND NAM SUGGEST
THAT A PIECE OR TWO OF UPPER LEVEL ENERGY COULD TRACK ACROSS
NORTHERN PARTS OF THE REGION. ADD IN MLCAPES 500-1000 J/KG AND THIS
COULD BE ENOUGH TO SPARK A FEW SHOWERS ACROSS THE NORTH/NORTHEAST.
CONFIDENCE NOT HIGH ENOUGH TO ADD TO THE FORECAST AT THE
MOMENT...BUT IF SIGNAL PERSISTS...SMALL CHANCES WILL BE NEEDED. PCPN
AMOUNTS WOULD BE MINIMAL.
FOR FRIDAY...THE GFS CONTINUES TO FAVOR KEEPING RAIN CHANCES
ASSOCIATED WITH A WEAK SHORTWAVE/LEFT-OVER CONVECTIVE COMPLEX SOUTH
OF THE AREA. A TREND IT STARTED YESTERDAY. THE ECMWF IS ALSO FARTHER
SOUTH...WHICH IT HINTED AT IN ITS PREVIOUS RUN. THE GEM WOULD BRING
US PRETTY GOOD RAINS...DUE TO DEVELOPING THE THU NIGHT STORM COMPLEX
A WHOLE STATE NORTH OF THE OTHER MODELS. GOING TO STICK WITH THE
SOUTHERN SOLUTIONS FOR NOW...WHICH HAS BEEN CONSENSUS.
MODELS HOLD THE PROMISE OF A DRY WEEKEND FOR THE REGION...WITH WEAK
SFC HIGH PRESSURE MOVING OVERHEAD AND ANY RIPPLES IN THE NORTHWEST
FLOW SHUTTLING NORTH OR SOUTH OF THE FORECAST AREA. OF COURSE...IN A
RELATIVELY DIRTY FLOW SUCH AS WHAT IS EXPECTED...THIS CAN CHANGE.
TEMPERATURES WILL BE MUCH MORE PLEASANT COMPARED TO LAST
WEEKEND...BUT THE PATTERN WILL STILL KEEP THEM NEAR OR BELOW THE
LATE JULY/EARLY AUGUST NORMALS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUL 29 2013
THE 29.12Z MODELS ARE IN GOOD AGREEMENT THAT A MID LEVEL SHORT
WAVE TROUGH WILL MOVE THROUGH THE REGION ON TUESDAY MORNING. A
BROKEN DECK INSTABILITY OF CUMULUS WILL BE SEEN ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON...AND THEN CONTINUE
INTO TONIGHT AS LOW LEVEL MOISTURE CONTINUES TO SURGE INTO THE
REGION. ARW AND RAP CONTINUE TO SUGGEST THAT SCATTERED SHOWERS
WILL MOVE INTO THE KRST AROUND 30.05Z...AND THEN CONTINUE THROUGH
THE REMAINDER OF THE MORNING. EXPECT THE CEILINGS TO BECOME MVFR
AFTER 30.09Z IN KRST. WITH SHOWERS SATURATING THE BOUNDARY LAYER
EXPECT THAT BR WILL REDUCE VISIBILITIES INTO THE MVFR RANGE FROM
30.09Z TO 30.15Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1247 PM CDT MON JUL 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT MON JUL 29 2013
QUIET WEATHER IN PLACE DURING THIS PERIOD. DEEP LOW PRESSURE AREA
CONTINUES TO PRESS EAST AND SKIES HAVE CLEARED. WAITING ON VALLEY
FOG TO FORM...WHICH SHOULD DISSIPATE QUICKLY THIS MORNING. HIGH
PRESSURE BUILDING IN AND SOUTHERLY RETURN FLOW HAS BEGUN IN THE
HIGH PLAINS WITH ABUNDANT CLOUD AND RAIN SHOWERS PER RADARS ACROSS
NEB/KS. 06Z PROFILER IN CENTRAL KS INDICATES ONE HOUR AVERAGE OF
40 KTS MOVING MOISTURE NORTH AND CONVERGING IT. THIS IN RESPONSE
TO MUDDLED SHORTWAVE TROUGH ENERGY OVER THE ROCKIES IN WRLY FLOW.
MOISTURE SOURCE IS STILL IN OK JUST SOUTH OF THE FRONT LYING FROM
SWRN CO TO ARKANSAS.
TONIGHT THE FRONTAL BOUNDARY IN THE SRN PLAINS WILL BEGIN TO LIFT
NORTH AND BECOME CONVECTIVELY ACTIVE AS SOUTHERLY FLOW BEGINS
ACROSS MOST OF THE PLAINS. A CONVECTIVE COMPLEX WILL RESULT OVER
I-80 CORRIDOR AND SOUTH...WITH BROAD MOISTURE ADVECTION ARRIVING
IN THE SWRN FORECAST AREA BY TUESDAY SUNRISE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 340 AM CDT MON JUL 29 2013
FORECAST CHALLENGES WERE THE WEAK LIFT ENVIRONMENT TUESDAY INTO
AND INCLUDING THE FRONTAL PASSAGE WEDNESDAY. SEVERE WEATHER
CHANCES WEDNESDAY WERE ALSO REFINED...VERY GOOD WIND SHEAR...POOR
FRONTAL CONVERGENCE AND LESSER CAPE.
300/305K ISENTROPIC SURFACES INDICATE VERY WEAK LIFT FROM KC-GRB
WITH MIXING RATIO VALUES INCREASING FROM 3 TO 9 G/KG RAPIDLY
TUESDAY MORNING. SOME WEAK CONVERGENCE WITH THIS ADVECTION OF HIGH
MOISTURE FROM W-E TUESDAY. WEATHER OUTCOME IS A 600-800MB LAYER
OF HIGH RH AND THICKER CLOUDS FOR TUESDAY. 29.00Z/03Z MODEL GUIDANCE
/SREF/NAM/GFS/ AGREE VERY WELL ON THIS FORECAST...INCREASING THE
CONFIDENCE. THIS CLOUD INCREASE WAS A MAJOR CHANGE TO THE
FORECAST. ALTHOUGH ONLY WEAK LIFT IS FORECAST...SOUTHERN TAIL OF
NORTHERN-PASSING SHORTWAVE TROUGH WILL ALSO PROVIDE A BIT OF
LIFT TUESDAY TO ALLOW SOME SHOWERS TO POSSIBLY POP UP. THUS...HAVE
AGAIN RE-ADDED THE RAIN CHANCES IN THE MOIST ENVIRONMENT
TUESDAY...THESE MAY NEED TO BE INCREASED MORE. WOULD THINK SOME
SCT/ISO SHRA WILL BE AROUND.
WHILE THE WEAK FORCING TUESDAY WEAKENS AND SHIFTS EAST TUESDAY
NIGHT...THE MOISTURE REMAINS TO ALLOW AGAIN AN ISO SHRA CHANCE.
ALL OF THESE ARE GROUND WETTING TYPE SYSTEMS AT MOST. A DRY PERIOD
UNTIL FRONTAL PASSAGE WEDNESDAY LOOKS ON TARGET. HOWEVER...WITH
TIMING ISSUES ON THE FRONT WEDNESDAY...DECIDED TO REMOVE DETAIL
ON THE RAIN CHANCES THAT DAY. HAVE ALSO INCREASED THE RAIN CHANCES
NORTH OF I-94 WITH IMPROVING CONSENSUS ON FORCING AND MOISTURE.THE
29.00Z GFS REMAINS THE FAST SOLUTION WITH THE FRONT...WHILE THE
NAM/ECMWF ARE SLOWER AND HAVE WARM ADVECTION ACROSS THE AREA
WEDNESDAY AT 12Z IN A PRE-FRONTAL ENVIRONMENT. BY 18Z WED...THE
GFS PUSHES THE FRONT THROUGH THE FORECAST AREA INTO CENTRAL
WI...AND HAVE SIDED MORE WITH THE SLOWER SOLUTIONS. 29.03Z SREF
MEAN WOULD BE A BIT OF A COMPROMISE OF THE TWO.
TARGETING THE 925 MB MOISTURE CONVERGENCE...THE BEST SIGNALS ARE
FURTHER NORTHWEST OF THE FORECAST AREA WHICH ISNT PREFERRED FOR
SEVERE WEATHER HERE. WOULD THINK AN AFTERNOON FRONTAL PASSAGE WILL
OCCUR WEDNESDAY WITH MLCAPE AROUND 1000 J/KG...INCREASING SWWRD
INTO IA. THE AREA WILL HAVE GOOD WIND SHEAR IN THE 0-6KM LAYER
WITH ORGANIZED STORMS POSSIBLE. RIGHT NOW THE QUESTION APPEARS TO
BE CONVERGENCE ON THE FRONT AND SUSTAINED FORCING FOR UPDRAFTS.
WOULD THINK IF THIS INCREASES IN FUTURE FORECASTS...A FEW
SUPERCELLS WOULD BE POSSIBLE. HOWEVER...THE SURFACE PRESSURE
GRADIENT AND WIND FLOW IS PRETTY WEAK IN MOST GUIDANCE...SO THINK
THE SEVERE WEATHER WILL BE ANYTHING ABOVE AN ISOLATE STORM OR TWO.
AREAS NORTH OF I-90...CLOSER TO THE STRONGER SHORTWAVE TROUGH
FORCING WOULD PROBABLY BE FAVORED...EVEN IN THE LESSER MLCAPE.
THURSDAY-SUNDAY...THIS PERIOD IS DOMINATED BY NORTHWEST FLOW AND
BELOW NORMAL TEMPERATURES. RAIN CHANCES CONTINUE THURSDAY NIGHT
TO FRIDAY NIGHT FOR A SYSTEM SHIFTING THROUGH THE NORTHWEST FLOW.
MOST OF THE RAIN CHANCES ARE TO THE SOUTH WITH MORE CONVECTIVE
INSTABILITY. THE CHALLENGE FOR WEATHER THIS PERIOD IS DEVELOPING
ENOUGH INSTABILITY IN THE NORTHWEST FLOW FOR GOOD CONVECTIVE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1247 PM CDT MON JUL 29 2013
THE 29.12Z MODELS ARE IN GOOD AGREEMENT THAT A MID LEVEL SHORT
WAVE TROUGH WILL MOVE THROUGH THE REGION ON TUESDAY MORNING. A
BROKEN DECK INSTABILITY OF CUMULUS WILL BE SEEN ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA THIS AFTERNOON...AND THEN CONTINUE
INTO TONIGHT AS LOW LEVEL MOISTURE CONTINUES TO SURGE INTO THE
REGION. ARW AND RAP CONTINUE TO SUGGEST THAT SCATTERED SHOWERS
WILL MOVE INTO THE KRST AROUND 30.05Z...AND THEN CONTINUE THROUGH
THE REMAINDER OF THE MORNING. EXPECT THE CEILINGS TO BECOM MVFR
AFTER 30.09Z IN KRST. WITH SHOWERS SATURATING THE BOUNDARY LAYER
EXPECT THAT BR WILL REDUCE VISIBILITIES INTO THE MVFR RANGE FROM
30.09Z TO 30.15Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
957 AM CDT MON JUL 29 2013
.UPDATE...CLOUDS ACROSS THE NORTHEAST HALF OF THE FORECAST AREA
ARE FAIRLY THIN GIVEN LATEST GRB SOUNDING AND RAP MODEL SOUNDINGS.
CONSEQUENTLY...THE SUN IS BEGINNING TO POKE THROUGH IN
SPOTS...WITH INCREASED HEATING/MIXING LIKELY TO HELP CLEAR THINGS
UP THROUGH LATE MORNING. THUS STILL EXPECTING HIGH TEMPS INTO THE
70S ACROSS THE FORECAST AREA THIS AFTERNOON.
&&
.AVIATION/18Z TAFS/...MVFR CIGS ACROSS THE NORTHEAST HALF OF THE
FORECAST AREA WILL IMPROVE BY LATE MORNING AS DAYTIME/HEATING
MIXING EATS AWAY AT THE LOW CLOUD DECK. SHOULD SEE A GOOD AMOUNT
OF SUN THEN FOR THE AFTERNOON.
IT SHOULD BE QUIET TONIGHT...WITH INCREASING MOISTURE POSSIBLY
BRINGING A RETURN OF SOME LOW CLOUDS AND A CHANCE FOR SHOWERS
TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT MON JUL 29 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
IMMEDIATE FORECAST CONCERN IS EARLY MORNING CLOUD COVER. LATEST
11-3.9 MICRON IMAGERY SHOWING RENEWED SWD PROGRESSION OF STRATUS
SHIELD OVER PORTIONS OF EAST CENTRAL WI. HOWEVER MORE BREAKS IN
THE CLOUDS OVER SOUTHEAST WI AS DRIER AIR AND INCREASING
SUBSIDENCE BUILD INTO THE REGION. STRATUS APPEARS FAIRLY SOLID
NORTH OF KSBM INTO NORTHEAST WI. WITH LOW LEVEL THERMAL TROUGH
LINGERING OVER EASTERN WI AT 12Z BEFORE WEAKENING...LIKELY TO BE
PERIOD OF BKN-OVC CLOUDS EARLY OVER THE EAST BEFORE THINNING.
EXPECT MORE CU TO REDEVELOP LATER THIS MRNG AND EARLY AFTN BUT
SHOULD REMAIN FEW-SCT FOR THE AFTN. WINDS TO TURN ONSHORE BY EARLY
AFTN...WHICH WILL KEEP LAKESHORE AREAS A FEW DEGREES COOLER.
BOTH GFS AND NAM INCREASE WEAK FORCING AFTER MIDNIGHT OVER SOUTH
CENTRAL WI AS LOW TO MID LEVEL MOISTURE RETURNS. PRECIPITABLE
WATER VALUES INCREASE AROUND THREE QUARTERS INCH BY 12Z IN THIS
AREA. HOWEVER 00Z NAM OUTLIER WITH STRONGER LOW LEVEL CONVERGENCE
ASSOCD WITH 85H JET AND APPROACHING WEAK MID-LEVEL 7H WAVE. NAM
ALSO SHOWING LITTLE CONSISTENCY FROM EARLIER RUNS. FOR NOW...WL
CONTINUE DRY FORECAST THRU 12Z WITH SCHC POPS SPREADING IN ON TUE.
SOME LIGHT FOG POSSIBLE IN LIGHT BOUNDARY LAYER WINDS LATER
TONIGHT IN ERN CWA BEFORE CLOUDS THICKEN.
TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
SHORT TERM MODELS SHOWING SOME DISAGREEMENT WITH FEATURES DURING
THIS PERIOD. THE NAM/CANADIAN/ECMWF SHOW LOW PRESSURE PASSING
SOUTH OF THE REGION TUESDAY INTO TUESDAY NIGHT. NAM ONLY MODEL
BRINGING QPF INTO THE SOUTHERN COUNTIES WITH THIS FEATURE...AS
850MB WARM AIR ADVECTION AND LOW LEVEL JET NOSE FOCUSES INTO
PORTIONS OF THE AREA. NAM MAY BE OVERDONE WITH THESE FEATURES AS
IT TENDS TO BE.
NAM FORECAST SOUNDINGS SHOW FAIRLY DEEP MOISTURE TUESDAY...BECOMING
SHALLOWER TUESDAY NIGHT. LITTLE TO NO INSTABILITY SHOWING UP
DURING THIS TIME. GFS DOES NOT SHOW THE LOW PASSING SOUTH OF THE
REGION TUESDAY INTO TUESDAY NIGHT.
THE CANADIAN AND GFS SHOW QPF WITH A PASSING 500MB VORTICITY
MAXIMUM MAINLY TUESDAY NIGHT INTO EARLY WEDNESDAY. THE ECMWF IS
FAIRLY DRY DURING THIS TIME. GFS FORECAST SOUNDINGS SHOWING
SIMILAR MOISTURE PROFILES TO THE NAM TUESDAY INTO TUESDAY
NIGHT...WITH A BIT MORE INSTABILITY. GFS SEEMS TO BE ODD MODEL OUT
DURING THIS TIME WITH ITS LACK OF A LOW TO THE SOUTH.
THE GFS/CANADIAN/ECMWF THEN BRING SURFACE COLD FRONT/500MB
VORTICITY MAXIMUM SOUTHEAST THROUGH THE REGION WEDNESDAY INTO
EARLY WEDNESDAY EVENING...WITH THE NAM AROUND 6 HOURS SLOWER. ALL
MODELS SHOW QPF WITH THE FRONTAL PASSAGE...WITH NAM/GFS FORECAST
SOUNDINGS SHOWING TALL SKINNY MEAN LAYER CAPE. DRIER AIR THEN
WORKS INTO THE AREA LATER WEDNESDAY NIGHT WITH COLD AIR ADVECTION.
GIVEN THE DIFFERENCES AMONG THE MODELS DURING THIS PERIOD...LEANED
TOWARDS CONSENSUS POPS AND TEMPERATURES. THIS LEFT LOWER END POPS
FOR TUESDAY INTO TUESDAY NIGHT...WITH HIGHER POPS WEDNESDAY INTO
WEDNESDAY EVENING WITH THE FRONTAL PASSAGE. TEMPERATURES SHOULD
REMAIN SLIGHTLY BELOW SEASONAL NORMALS.
THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
GFS/ECMWF THEN SHOW FAIR AGREEMENT IN THIS PERIOD. THURSDAY LOOKS
DRY WITH HIGH PRESSURE INFLUENCE STILL OVER THE AREA. MODELS IN
BETTER AGREEMENT WITH COLD FRONTAL PASSAGE AND QPF TIMING ON
FRIDAY...WITH GFS WETTER THAN ECMWF WITH QPF. 500MB VORTICITY
MAXIMUM PASSES THROUGH FRIDAY AS WELL. HIGH PRESSURE FROM THE
NORTH THEN BRINGS COOLER AND DRIER AIRMASS INTO THE REGION
SATURDAY INTO SUNDAY ACROSS THE REGION.
GIVEN SOME OF THE DIFFERENCES IN THIS PERIOD...WENT WITH CONSENSUS
POPS AND TEMPERATURES. HIGHEST POPS WILL BE FRIDAY INTO FRIDAY
NIGHT WITH THE FRONTAL PASSAGE. TEMPERATURES SHOULD REMAIN AROUND
OR SLIGHTLY BELOW SEASONAL NORMALS.
AVIATION/12Z TAFS/...BRIEF PERIOD OF MVFR CIGS MAY AFFECT ERN
TAF SITES EARLY THIS MRNG AS LAST VESTIGES OF LOW LEVEL COLD AIR
ADVECTION AND THERMAL TROF LINGER IN THE AREA BEFORE SHIFTING OFF
TO THE EAST. OTRW...MAINLY FEW-SCT CU EXPCD TO REDEVELOP LATER
THIS MRNG AND AFTN. VFR CONDITIONS TO CONTINUE TNGT. ERN TAF SITES
MAY EXPERIENCE LIGHT FOG AFT MIDNIGHT DUE TO LIGHT BOUNDARY LAYER
FLOW BEFORE MID/HIGH CLOUDS THICKEN LATE.
MARINE...NORTHWEST WINDS WILL CONTINUE TO SUBSIDE AS PRESSURE
GRADIENT RELAXES OVER LAKE MI THIS MORNING. EXPECT WINDS TO TURN
ONSHORE LATE THIS MRNG AND EARLY AFTERNOON AS LAKE BREEZE
DEVELOPS. WINDS LOOK TO REMAIN MAINLY LESS THAN 20 KNOTS FOR THE
FORESEEABLE FUTURE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...MBK
TUESDAY THROUGH SUNDAY...WOOD
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1127 AM MDT MON JUL 29 2013
.UPDATE...
ISSUED AT 935 AM MDT MON JUL 29 2013
MINOR CHANGES TO TODAYS FORECAST. LOWERED POPS THE REST OF THIS
MORNING AND DECREASED SKY COVER. STILL EXPECTING ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON AS
THE LOW LEVELS DESTABILIZE. CLOUD COVER HAS SLOWED THE RISE OF
TEMPERATURES THIS MORNING BUT THE HIGH TEMPERATURE FORECAST LOOKS
IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1127 AM MDT MON JUL 29 2013
MVFR CONDITIONS WILL CONTINUE INTO THIS AFTERNOON OVER MUCH OF THE
NEBRASKA PANHANDLE WITH SLOW IMPROVEMENT. WIDELY SCATTERED SHOWERS
AND TSTMS DEVELOPING ALONG THE LARAMIE RANGE BY MID-AFTN SHOULD THEN
SPREAD EASTWARD OVER THE PLAINS THROUGH THE EVENING BEFORE ENDING.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...RE
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
938 AM MDT MON JUL 29 2013
.UPDATE...
ISSUED AT 935 AM MDT MON JUL 29 2013
MINOR CHANGES TO TODAYS FORECAST. LOWERED POPS THE REST OF THIS
MORNING AND DECREASED SKY COVER. STILL EXPECTING ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON AS
THE LOW LEVELS DESTABILIZE. CLOUD COVER HAS SLOWED THE RISE OF
TEMPERATURES THIS MORNING BUT THE HIGH TEMPERATURE FORECAST LOOKS
IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 547 AM MDT MON JUL 29 2013
IFR CONDITIONS WILL CONTINUE OVER MUCH OF THE PLAINS THROUGH THE
MID-MORNING. LOW CLOUDS WILL THEN SCATTER OUT BY LATE MORNING.
EXPECT SHOWERS AND TSTMS TO DEVELOP ALONG THE LARAMIE RANGE BY THE
EARLY AFTN THEN SPREAD EASTWARD OVER THE PLAINS THROUGH THE
EVENING. WINDS WILL GENERALLY BE LESS THAN 15 KTS...EXCEPT NEAR
STORMS WHERE BRIEF GUSTY WINDS WILL BE POSSIBLE.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...FINCH
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
558 AM MDT MON JUL 29 2013
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 547 AM MDT MON JUL 29 2013
IFR CONDITIONS WILL CONTINUE OVER MUCH OF THE PLAINS THROUGH THE
MID-MORNING. LOW CLOUDS WILL THEN SCATTER OUT BY LATE MORNING.
EXPECT SHOWERS AND TSTMS TO DEVELOP ALONG THE LARAMIE RANGE BY THE
EARLY AFTN THEN SPREAD EASTWARD OVER THE PLAINS THROUGH THE
EVENING. WINDS WILL GENERALLY BE LESS THAN 15 KTS...EXCEPT NEAR
STORMS WHERE BRIEF GUSTY WINDS WILL BE POSSIBLE.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...FINCH
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
426 AM MDT MON JUL 29 2013
.SHORT TERM...(TODAY AND WEDNESDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
SATELLITE PIX AND AREA WEBCAMS SHOW AN AREA OF FOG...THICKEST
ALONG THE INTERSTATE 80 CORRIDOR FROM CHEYENNE TO SIDNEY EARLY
THIS MORNING. THIS FOG IS A RESULT OF MOIST LLVL SE FLOW ALONG
THE EASTERN PLAINS. SOME IMPROVEMENT HAS BEEN NOTED OVER THE PAST
HOUR AT KCYS AS WINDS HAVE TURNED WESTERLY. 00Z NAM AND HRRR HAVE
HANDLED THIS WELL...SO SHOULD SEE FOG GRADUALLY LIFT FROM WEST OF
EAST THROUGH MID-MORNING. OTHERWISE....KCYS 88D WAS RETURNING SOME
WEAK SHOWER ACTIVITY MOVING EAST ACROSS THE PANHANDLE. THIS
ACTIVITY WILL HAVE PUSHED EAST OF THE CWFA BY SUNRISE...LEAVING A
PARTLY/MOSTLY CLOUDY START TO THE DAY. THIS CLOUD COVER WILL BREAK
UP SUFFICIENTLY TO ALLOW FOR DESTABILIZATION BY MIDDAY AND WHEN
COMBINED WITH INCREASING MID-LEVEL MOISTURE AND AN APPROACHING
SHORTWAVE WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS. LLVL THETA-E RIDGE WILL TAKE
RESIDENCY ACROSS THE WESTERN NEBRASKA PANHANDLE BY AFTERNOON.
CORRESPONDING PROGD SBCAPES OF 700-1200 J/KG WILL AID IN
CONVECTIVE ORGANIZATION THERE. SO BY MIDDAY...WILL SEE CONVECTION
DEVELOPING ACROSS THE SE WYOMING MOUNTAINS AND ADJACENT PLAINS.
EVENTUALLY THIS ACTIVITY WILL TRANSLATE EAST INTO THE EASTERN
PLAINS LIKELY GAINING STRENGTH THROUGH THE AFTERNOON /EVENING.
ALTHOUGH DO NOT EXPECT MUCH OF A SEVERE THREAT...WOULD NOT BE
SURPRISED TO SEE ONE OR TWO STORMS APPROACH THAT STRENGTH. STORM
MOTIONS OF LESS THAN 10 KNOTS COMBINED WITH PWATS OF 125-150
PERCENT OF NORMAL SUGGEST HEAVY RAIN WILL BE THE PRIMARY HAZARD OF
CONCERN. THE SHORTWAVE WILL SLOWLY ROTATE THRU TONIGHT...SO HAVE
MAINTAINED A CHANCE OF LINGERING CONVECTION INTO THE OVERNIGHT
HOURS AS WELL.
FOR TUESDAY...WINDS WILL TURN MORE WESTERLY BEHIND MONDAY NIGHTS
SHORTWAVE PASSAGE WHICH WILL PUSH LLVL MOISTURE AND RESULTANT LLVL
THETA-E RIDGING ACROSS FAR EASTERN ZONES. TUESDAY WILL OFFER LESS
CONVECTIVE COVERAGE COMPARED TO TODAY...WITH BEST CHANCES ACROSS
FAR EASTERN ZONES. ONCE AGAIN LIMITED INSTABILITY WILL SUPPRESS
ANY CHANCE FOR WIDESPREAD SEVERE CONVECTION. SFC BOUNDARY WILL
SLIDE SOUTH TUESDAY NIGHT...SO HAVE KEPT LINGERING THUNDERSTORM
CHANCES ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE.
FLOW TURNS NORTHWEST FOR WEDNESDAY. LLVL FLOW WILL SLOWLY TURN TO
THE SOUTHWEST DURING THE DAY...BUT LIKELY WONT HAVE ENOUGH TIME TO
ADVECT SUFFICIENT MOISTURE FOR ANYTHING MORE THAN WEAK
INSTABILITY. AS SUCH...EXPECT TO SEE SOME WEAK DEVELOPMENT ALONG
THE LARAMIE RANGE...ROLLING OUT ONTO THE ADJACENT EASTERN PLAINS
BY LATE AFTERNOON AND EVENING.
LLVL THERMAL RIDGE WILL GRADUALLY AMPLIFY UPSTREAM THROUGH THE
PERIOD. SO WILL SEE HIGH TEMPERATURES WARM WELL INTO THE 80S FOR
TODAY AND TUESDAY...TEMPERED SOME WEDNESDAY FOR EASTERN ZONES BY
TUESDAY NIGHTS WEAK FROPA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 418 AM MDT MON JUL 29 2013
LOOKS LIKE THERE WILL BE A CHANCE OF AFTN AND EVENING TSTMS MOST
DAYS IN THE EXTENDED...ESPECIALLY OVER THE PLAINS. MIDLEVEL RIDGE
AXIS IS POSITIONED ACROSS CENTRAL WY ON THURS WITH SE SFC WINDS IN
NEBRASKA. CAPE VALUES AROUND 2000 J/KG WILL COMBINE WITH SUFFICIENT
DEEP LAYER SHEAR TO PRODUCE SOME STRONGER DISCRETE CELLS. WHILE
HEAVY RAIN WILL BE POSSIBLE WITH PW VALUES ABOVE 1 INCH...STEERING
FLOW OF 25-30 KTS SHOULD KEEP FLOODING THREAT DOWN. SYNOPTIC
PATTERN DOES NOT CHANGE MUCH FOR FRIDAY. SFC HIGH PRESSURE OVER THE
NORTHERN PLAINS WILL CONTINUE THE EAST-TO-SOUTHEAST FLOW AT THE
SFC. THETA-E AXIS STRETCHES FROM THE PANHANDLE INTO NIOBRARA COUNTY
WITH CAPE VALUES APPROACHING 2500 J/KG. COULD BE SEVERE STORMS ONCE
AGAIN WITH THE FAVORABLE SHEAR PROFILE. FLOW ALOFT BECOMES MORE
SOUTHWESTERLY BY THE WEEKEND. WHILE PW VALUES DROP FOR AREAS ALONG
AND WEST OF THE LARAMIE RANGE ON SATURDAY AND SUNDAY...THEY REMAIN
ABOVE NORMAL OVER MUCH OF THE PLAINS AS THE SOUTH-TO-SOUTHEAST
UPSLOPE AND MOISTURE ADVECTION PERSISTS. THE GFS SUGGESTS THAT
STRONG AND SEVERE STORMS WOULD BE POSSIBLE INTO THE WEEKEND OVER THE
PANHANDLE WHILE SOUTHEAST WY WOULD DRY OUT SOME. TEMPS WILL BE
AROUND NORMAL THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1051 PM MDT SUN JUL 28 2013
PROLONGED AND EXPANSIVE IFR EVENT UNDERWAY WITH LOW CEILINGS AT
KAIA...KSNY AND JUST RECENTLY HERE AT KCYS. HRR HAS A GREAT HANDLE
ON THIS STRATUS AND USED IT FOR MY GUIDANCE ON THE 06Z TAFS.
STRATUS TO STAY IN WHERE IT IS IN THE SOUTHERN/CENTRAL PANHANDLE
AND HERE AT KCYS THROUGH 12Z. THEN BEGINS TO LIFT AT KCYS AFTER
13Z OR SO. MAY TAKE A LITTLE LONGER TO BREAK IN THE PANHANDLE.
CONCERN IS FOR KCDR. THEY ARE GOING TO SEE A LINE OF SHOWERS MOVE
THROUGH UP THERE THAT SHOULD HELP KEEP THEM UP FOR A WHILE. WITH A
SOUTHEAST DOWNSLOPE WIND OFF THE PINE RIDGE...CONFIDENCE IS
SOMEWHAT HIGH THAT THEY SHOULD STAY MVFR OR BETTER THROUGH THE
OVERNIGHT HOURS.
&&
.FIRE WEATHER...
ISSUED AT 418 AM MDT MON JUL 29 2013
DAILY AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES WILL
SUPPRESS FIRE WEATHER CONCERNS THROUGH EARLY IN THE WEEK. OF
COURSE...SOME OF THESE THUNDERSTORMS MAY PROVIDE ADDITIONAL FIRE
STARTS. HOWEVER...SLOWLY MOVEMENT OF THIS ACTIVITY WILL LIKELY
PROVIDE A BOOST TO THE CHANCE OF WETTING RAINS. MINIMUM RELATIVE
HUMIDITIES WILL LIKELY ONLY FALL INTO THE 20S MONDAY AND
TUESDAY...WITH PERHAPS A FEW UPPER TEENS CREEPING IN OVER CARBON
COUNTY BY WEDNESDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...HAHN
LONG TERM...FINCH
AVIATION...CLAYCOMB
FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
431 AM EDT WED JUL 31 2013
.SHORT TERM /TODAY THROUGH THURSDAY/...
RAIN ALREADY RETURNING TO THE AREA TODAY AS PERTURBATIONS MOVE
THROUGH THE UPPER LEVEL FLOW. MEDIUM RANGE AND HI RES MODELS ARE
IN AGREEMENT THAT THE CWA WILL SEE CONVECTION TODAY...HOWEVER
CONSIDERABLE DISAGREEMENT IN TERMS OF TIMING. WRF NMM SEEMS TO
HAVE A SURGE IN CONVECTION DURING THE MORNING THAN A LULL DURING
THE AFTERNOON. LOCAL WRF TENDS TO WEAKEN CONVECTION THIS
MORNING...DEVELOP ACROSS CENTRAL GEORGIA THIS AFTERNOON AND THEN
ACROSS THE NORTH DURING THE LATE AFTERNOON. HRRR CONTINUES TO
SHIFT THE CURRENT CONVECTION TO THE EAST AND THEN DEVELOP
CONVECTION ACROSS THE ENTIRE CWA AS THE AFTERNOON APPROACHES.
GIVEN ALL OF THIS AND MEDIUM RANGE MODELS...GOOD CONFIDENCE OF
HIGH POPS FOR TODAY...HOWEVER LOW CONFIDENCE IN TERMS OF TIMING.
FORECAST IS MOST CLOSELY IN LINE WITH THE HRRR.
FOR THE STORMS CURRENTLY ONGOING...MAIN CONCERN IS GUSTY WINDS. GFS
CAPE FORECAST LOOKS MORE REASONABLE TODAY...RATHER THAN LAST NIGHT
WHERE IT WAS GAPPING THE CWA WITH INSTABILITY. FORECAST CAPE VALUES
ARE AROUND 1500-2000 J/KG FOR THE AFTERNOON. STILL EXPECTING BETWEEN
20 AND 30KTS OF DEEP LAYER SHEAR TODAY AND BETWEEN THIS AND THE
INSTABILITY VALUES...COULD SEE ISOLATED SEVERE STORMS. MAIN THREAT
WILL BE DAMAGING WINDS. ALTHOUGH THE CWA HAS HAD A FEW DAYS WITHOUT
RAIN...ALLOWING US TO BE ABLE TO HANDLE MORE IN TERMS OF
RAINFALL...WILL STILL HAVE TO MONITOR RAINFALL AMOUNTS CLOSELY.
AROUND ONE TO ONE AND A HALF INCHES OF RAIN IS EXPECTED THROUGH
THURSDAY...WITH LOCALIZED HIGHER AMOUNTS POSSIBLE. 1HR FFG VALUES
ARE AROUND 2.5 TO 3.5 INCHES SO WE SHOULD BE ABLE TO HANDLE THESE
AMOUNTS...BUT THERE IS THE POTENTIAL FOR LOCALIZED FLOODING WITH
HIGHER RAINFALL VALUES.
SFC FRONT MOVES THROUGH CWA ON THURSDAY. CONVECTION SHOULD DECREASE
BY THURSDAY MORNING...BUT THEN INCREASE AGAIN ON THURSDAY ALONG AND
SOUTH OF THIS FRONT.
11
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AT THE BEGINNING OF THE PERIOD A WEAK FRONTAL BOUNDARY WILL BE
MOVING INTO CENTRAL GEORGIA. CONVECTION ASSOCIATED WITH THIS
BOUNDARY MAY BE ONGOING. EXPECT THIS CONVECTION TO BE ON A GENERAL
WEAKENING TREND THROUGH THE EVENING. AT THIS POINT FRIDAY LOOKS TO
BE THE BEST DAY FOR NO POPS ACROSS THE REGION AS WE WAIT FOR
NORTHWEST FLOW TO BRING US ANOTHER IMPULSE AND RAIN TO THE AREA.
MOISTURE ASSOCIATED WITH DORIAN SHOULD HELP IN INCREASE PWATS AND
RAIN CHANCES THIS WEEKEND AND INTO NEXT WEEK. THE MODELS SUGGEST
THAT WE KEEP NORTHWEST FLOW THROUGH AT LEAST MID NEXT WEEK...WHEN
THEY TRY TO BUILD A RIDGE INTO THE SOUTHERN UNITED STATES. MAY
CONCERN IN THE EXTENDED COULD BE RAINFALL ASSOCIATED WITH THE
SHOWERS AND THUNDERSTORMS THIS WEEKEND AND INTO EARLY NEXT WEEK.
THIS WILL NEED TO BE MONITORED CLOSELY FOR POSSIBLE FLOODING AS WE
APPROACH THIS WEEKEND.
ARG
&&
.AVIATION...
06Z UPDATE...
CONVECTIVE ACTIVITY IS A LITTLE EARLIER THAN EXPECTED SO MOVED UP
TIMING OF SHRA IN THE TAFS. ALTHOUGH ISOLD TSRA ARE POSSIBLE THIS
MORNING...BETTER CHANCES STILL REMAIN INTO THE AFTERNOON. STILL
THE POTENTIAL FOR MVFR VSBYS AT AHN AND MCN THIS MORNING BUT
CONFIDENCE IS LOW. WIND SHIFT IS EXPECTED THIS AFTERNOON AT ATL
FROM SE TO SW BUT WIDE RANGE OF TIMING IN THE MODELS AND FORECAST
TIMING IS IN THE MIDDLE OF THE SOLUTIONS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON VSBYS. LOW CONFIDENCE ON CIGS. LOW CONFIDENCE ON
WIND...DUE TO DIRECTION LATE MORNING INTO THE AFTERNOON. LOW
CONFIDENCE ON TIMING OF SHRA/TSRA.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 69 88 68 / 90 70 30 20
ATLANTA 84 71 87 70 / 80 70 30 10
BLAIRSVILLE 77 66 83 62 / 80 60 20 10
CARTERSVILLE 85 69 88 66 / 80 60 20 10
COLUMBUS 88 72 91 72 / 70 60 50 30
GAINESVILLE 82 70 86 68 / 80 70 30 10
MACON 87 71 90 70 / 80 70 50 30
ROME 84 70 89 66 / 80 60 20 10
PEACHTREE CITY 84 70 87 66 / 80 70 30 20
VIDALIA 88 73 88 72 / 60 50 60 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....ARG
AVIATION...11
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1129 PM MDT TUE JUL 30 2013
.UPDATE...
ISSUED AT 847 PM MDT TUE JUL 30 2013
SMALL AREA OF THUNDERSTORMS OVER FRONTIER COUNTY CONTINUES TO MOVE
SOUTHWARD INTO THE DRIER AIR. DO NOT EXPECT IT TO SUDDENLY
DISSIPATE BEFORE REACHING RED WILLOW COUNTY SO HAVE FAIRLY HIGH
CHANCES FOR PRECIP. CHANCES THERE. PRECIP. CHANCES DECLINE
FURTHER SOUTH SINCE THE STORM WILL CONTINUE TO BE IN THE DRIER AIR
WHICH SHOULD CAUSE IT TO EVENTUALLY DISSIPATE COMPLETELY.
OVERNIGHT A PLUME OF MOISTURE AHEAD OF AN UPPER LEVEL
TROUGH...CURRENTLY OVER WYOMING...WILL MOVE OVER THE NORTHERN PART
OF THE AREA. SOUNDINGS SHOW SOME ELEVATED INSTABILITY AS THE SHORT
WAVE TROUGH MOVES THROUGH. AS A RESULT WILL HAVE SOME SLIGHT
CHANCES GOING DURING THE OVERNIGHT/EARLY MORNING HOURS AS THE
SHORT WAVE TROUGH MOVES THROUGH.
SOUNDINGS OVER THE EASTERN HALF OF THE AREA ARE STILL SUGGESTING
FOG DEVELOPMENT TONIGHT. DO NOT ANTICIPATE IT TO BE AS THICK AS THE
LAST COUPLE OF NIGHTS DUE TO THE RATHER SHALLOW DEPTH TO THE
SATURATION.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 PM MDT TUE JUL 30 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS ELONGATED RIDGE ACROSS
THE SOUTHERN PLAINS WITH WESTERLY FLOW IN PLACE ACROSS THE
CENTRAL/HIGH PLAINS. A WEAK LEE TROUGH IS CURRENTLY IN PLACE ACROSS
EASTERN COLORADO WITH A WEAK CONVERGENCE REGION EXTENDING INTO OUR
WESTERN CWA.
THIS WILL ACT AS THE FOCUS FOR ISOLATED THUNDERSTORM DEVELOPMENT
THIS AFTERNOON...WITH CU FIELD ALREADY IN PLACE AND RADAR INDICATING
SEVERAL DEVELOPING UPDRAFTS JUST NW OF OUR CWA NEAR YUMA COUNTY. WITH
STORM MOTIONS OUT OF THE EAST 10-20KT MOST STORMS WILL BE SLOW
MOVERS...THOUGH WE COULD STILL SEE THIS ACTIVITY MOVE FURTHER EAST
IN OUR CWA THROUGH THE AFTERNOON BEFORE FALLING APART AFTER SUNSET
WITH LOSS OF DAYTIME HEATING AND INCREASING LOW LEVEL CINH. LATEST
RAP ANALYSIS SHOWS SB/ML CAPE VALUES RANGING FROM 1000-1500
J/KG...AND WITH ADJUSTED SOUNDINGS SUPPORTING POSSIBLE CAPE VALUES
IN THE 2000-2500J/KG RANGE LATER THIS AFTERNOON. WITH HIGH TD
DEPRESSIONS TO ABOUT 700MB THROUGH A DRY ADIABATIC AIR MASS AND HIGH
LFC/LCL IN THE 10-13KFT RANGE WE COULD SEE STRONG THUNDERSTORM GUST
POTENTIAL. IF WE REALIZE THE HIGHER CAPE VALUES I COULDNT RULE OUT
LARGE HAIL POTENTIAL...HOWEVER AT THIS POINT STRONG WINDS ARE
PROBABLY THE GREATER THREAT WITH ANY THUNDERSTORMS THAT DEVELOP.
MET/MAV GUIDANCE ARE INDICATING FOG DEVELOPMENT TONIGHT...HOWEVER
WITH W-SW WINDS TO 10KT AT THE SURFACE AND BL WINDS IN EXCESS OF
20KT...I AM NOT AS CONFIDENT WE WILL SEE A REPEAT OF LAST NIGHT.
WITH TROUGH AXIS SHIFTING EAST WE COULD STILL SEE LIGHT SURFACE
WINDS IN THE EAST WHERE FOG WOULD BE MORE LIKELY TO OCCUR...AND
WHERE I KEPT PATCHY FOG MENTION.
A WEAK COLD FRONT WILL DROP SOUTH LATE TONIGHT AND STALL ALONG THE
NE/KS STATE LINE BY MIDDAY WEDNESDAY WITH A PRE FRONTAL TROUGH
SETTLING TO OUR SOUTHEAST. AHEAD OF THE TROUGH AXIS CAPE VALUES IN
EXCESS OF 2500 J/KG ARE ADVERTISED. THIS TROUGH AXIS WILL BE THE
MAIN FOCUS WITH GOOD SURFACE CONVERGENCE IN PLACE...AND I KEPT 30/40
POPS TIED TO THIS FEATURE...AND LOWER POPS TO THE NORTH. WITH BETTER
CAPE AND MARGINALLY BETTER SHEER WE WILL SEE A CHANCE FOR
THUNDERSTORMS TO BECOME BETTER ORGANIZED WITH SEVERE WIND/HAIL A
POSSIBILITY IN OUR SOUTHEAST DURING THE AFTERNOON.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 250 PM MDT TUE JUL 30 2013
NO MAJOR CHANGES SEEN TO THE UPPER PATTERN ACROSS THE SOUTHERN AND
CENTRAL PLAINS DURING THIS PERIOD. UPPER HIGH NOW CENTERED OVER
NEW MEXICO AND WAFFLE BACK AND FORTH OVER TO WEST TEXAS AND BACK DURING
PERIOD. ALTHOUGH THE UPPER RIDGE IS FORECAST TO ASSERT ITSELF SLIGHTLY
NORTH OVER THE MOUNTAINS...A SERIES OF WEAK UPPER IMPULSES WILL
CONTINUE TO MOVE OVER THE TOP OF THE RIDGE KEEPING IT FAIRLY
FLAT OVERALL.
THIS MAKES IT DIFFICULT TO ASSESS TIMING OF PRECIPITATION. ALL
GUIDANCE IS SUGGESTING AN ACTIVE FLOW REGIME WILL CONTINUE WITH
SLIGHT CHANCE TO CHANCE POPS EVERY DAY. RIGHT NOW THE MOST ACTIVE
PERIODS FOR PRECIPITATION LOOK TO BE THURSDAY NIGHT AND AGAIN
SATURDAY NIGHT. TEMPERATURES WILL CONTINUE SEASONAL WITH HIGHS
MOSTLY IN THE UPPER 80S TO LOWER 90S AND LOWS IN THE 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1108 PM MDT TUE JUL 30 2013
MVFR TO VFR CONDITIONS FORECAST FOR THE 6Z TAFS. LATEST RADAR
SHOWS AN AREA OF STORMS OVER SOUTHWEST NEBRASKA MOVING TO THE
SOUTHEAST. IF STORMS KEEP THEIR CURRENT COURSE/SPEED THEY WILL BE
MOVING OVER KMCK AROUND 6Z. BASED ON OGALLALA/S OBSERVATION IFR
CONDITIONS ARE POSSIBLE WHEN THE STORM MOVES THROUGH KMCK. HOWEVER
THE STORMS SHOULD BE MOVING OUT OF THE LOW LEVEL JET BY THE TIME
THEY ARE NEAR KMCK...SO THEIR INTENSITY SHOULD DIMINISH. THE
OBSERVATION FROM KIML WILL HELP DECIDE HOW LOW TO GO FOR KMCK..BUT
AM HESITANT TO GO TOO LOW SINCE THE STORM SHOULD BE WEAKENING BY
THEN. OTHERWISE ISOLATED TO SCATTERED STORMS WILL BE POSSIBLE FOR
KMCK UNTIL ALMOST THE EARLY MORNING AHEAD OF AN UPPER LEVEL TROUGH
THAT WILL MOVE THROUGH AROUND 12Z. THERE COULD BE SOME FOG LATE
TONIGHT FOR KMCK. SOUNDINGS ARE NOT TOO FAVORABLE FOR FOG
DEVELOPMENT...BUT MCK HAS FAIRLY HIGH DEW POINTS AND HAS NOT YET
CHANGED AIR MASSES...SO WILL PLACE A MENTION OF FOG IN THE TAF FOR
NOW.
WEDNESDAY STORMS SHOULD INITIALLY DEVELOP DURING THE EARLY
AFTERNOON ALONG A WEAK COLD FRONT. AS THE DAY PROGRESSES THE COLD
FRONT WILL MOVE FURTHER SOUTH...TAKING THE STORMS WITH IT. STORM
COVERAGE NEAR THE SITES SHOULD DECLINE THROUGH THE AFTERNOON AS A
RESULT. THERE MAY BE SOME MORE WIDELY SCATTERED STORMS DURING THE
EVENING AS SOME ELEVATED INSTABILITY WILL BE IN PLACE AS ANOTHER
SHORT WAVE TROUGH MOVES THROUGH...BUT WILL LEAVE OUT A MENTION OF
STORMS FOR THIS TIME FRAME.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...DLF
AVIATION...JTL
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1207 AM CDT WED JUL 31 2013
...UPDATED FOR AVIATION...
.UPDATE...
ISSUED AT 630 PM CDT TUE JUL 30 2013
HAVE A CONCERN THROUGH THE OVERNIGHT HOURS FOR DENSE FOG. WET GROUNDS
FROM ANTECEDENT RAINS AND CALM WINDS WILL CREATE AN ENVIRONMENT THAT
IS CONDUCIVE FOR DENSE FOG. THIS IS SUGGESTED WITH HRRR AND BUFKIT GUIDANCE
AS WELL AS SOME MOS GUIDANCE. AS A RESULT, HAVE ISSUED A DENSE FOG ADVISORY.
SECOND CONCERN WAS TO REMOVE ANY STORM CHANCES THIS EVENING AS ACTIVITY
IS NORTHWEST KANSAS IS WEAKENING AND CUMULUS ACROSS THE KANSAS/COLORADO
BORDER IS NOT UNDERGOING ADEQUATE VERTICAL GROWTH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 156 PM CDT TUE JUL 30 2013
TODAY IS SEEING A VERY SLOW CLEARING PATTERN IN THE CLOUDS FROM
WEST TO EAST. THIS SLOWNESS IN CLEARING IS PARTIALLY DUE TO THE
NORTH TO NORTHEAST LOW LEVEL FLOW, WHICH IS A SLIGHT UPSLOPE
PATTERN. THE OTHER REASON THE EAST IS SO SLOW TO CLEAR OUT IS THE
ABUNDANT SURFACE MOISTURE ACROSS OUR EASTERN ZONES, WITH PLENTY OF
LEFTOVER RAINFALL STILL ACROSS MUCH OF THE EASTERN FORECAST AREA,
ESPECIALLY SOUTHEAST OF A LINE FROM LA CROSSE TO ASHLAND. SOME OF
THESE COUNTIES RECEIVED OVER 3 INCHES OF RAINFALL MONDAY EVENING,
ESPECIALLY ACROSS PRATT AND BARBER COUNTIES. FOR THIS REASON, ALONG
WITH EXPECTED CLEAR SKIES AND LIGHT WINDS EXPECTED, THERE SHOULD
BE SOME MORE FOG FORM TOWARD 09Z TO 10Z. I HAVE DECIDED TO PUT IN
PATCHY FOG WORDING FOR NOW ACROSS OUR SOUTHEASTERN SECTIONS, AND
LATER SHIFTS CAN UPDATE TO DENSE FOG IF IT FORMS. BOTH THE NAM
AND THE HRRR MODELS ARE INDICATED AROUND 1SM VISIBILITIES IN FOG.
AS FOR LOW TEMPERATURES, NO CHANGES WERE MADE TO THE PREVIOUS
FORECAST. CLEAR SKIES AND LIGHT WINDS WILL ALLOW TEMPERATURES TO
DROP TO THE MID 60S IN OUR WEST AND THE UPPER 60S IN OUR
SOUTHEAST.
MOSTLY SUNNY SKIES AREA EXPECTED WEDNESDAY, AFTER SOME SCATTERED
MORNING FOG. WINDS WILL BE LIGHT AND VARIABLE EARLY, THEN SHIFT TO
THE SOUTHEAST IN THE AFTERNOON AT 10 TO 20 MPH. A COLD FRONT
WILL APPROACH WESTERN KANSAS BY AFTERNOON. THE NAM MODEL BRINGS IN
THUNDERSTORMS WEDNESDAY AFTERNOON AS EARLY AS 19Z IN OUR NORTHWEST
ZONES OF SCOTT AND LANE COUNTIES, AND ADVANCES THE RAIN TOWARD
DODGE CITY AS EARLY AS 22Z. THE ECMWF AND GFS MODELS ARE A LITTLE
SLOWER, BRINGING RAIN TO SCOTT AND LANE COUNTIES AFTER 22Z AND NOT
NEAR DODGE CITY UNTIL AFTER 02Z. HAVE STARTED SLIGHT 20 PERCENT
CHANCES IN OUR FAR NORTHWEST, SUCH AS SCOTT AND LANE COUNTIES, AND
DELAYED THE ONSET OF CHANCE POP CATEGORIES IN THE DODGE CITY AREA
UNTIL 03Z. SOME OF THE LATE AFTERNOON AND EVENING STORMS COULD
CONTAIN DAMAGING WINDS AND HAIL AS LARGE AS GOLF BALLS. THE FRONT
WILL MOVE THROUGH WESTERN AND INTO CENTRAL KANSAS BY WEDNESDAY
EVENING, BRINGING RAIN CHANCES FOR SHOWERS AND THUNDERSTORMS TO
THE PRATT AND COLDWATER AREAS AFTER 00Z THURSDAY. WITH SKIES
STARTING OUT WEDNESDAY MORNING AS MOSTLY SUNNY, THEN BECOMING
PARTLY CLOUDY BY MID TO LATE AFTERNOON, AND POSSIBLY EVEN MOSTLY
CLOUDY BY EVENING, MAXIMUM TEMPERATURES COULD BE A LITTLE TRICKY.
STAYED WITH THE PREVIOUS FORECAST OF MID 90S IN THE WEST AND NEAR
90F IN THE EAST. HOW MUCH RAIN WILL FALL IS ALWAYS A LITTLE
CHALLENGING, BUT I THINK THE QPF_FM_POP PROCEDURE DID A FAIRLY
GOOD JOB WITH FORECAST RAINFALL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 339 PM CDT TUE JUL 30 2013
AN UPPER LEVEL LONGWAVE TROUGH WILL GENERALLY RESIDE OVER THE EASTERN
UNITED STATES THROUGH TUESDAY AUGUST 6TH, WITH UPPER LEVEL RIDGING
WAFFLING BACK AND FORTH BETWEEN NEW MEXICO AND TEXAS. ALONG THE
NORTHERN PERIPHERY OF THE RIDGE OVER THE CENTRAL HIGH PLAINS, A
QUASI-STATIONARY SURFACE FRONTAL BOUNDARY WILL EXIST, WITH LOW
LEVEL MOISTURE CONVERGING ALONG AND NORTH OF THE BOUNDARY.
ADDITIONALLY, EVAPOTRANSPIRATION FROM THE PREVIOUS HEAVY RAINS
ACROSS THE SOUTHERN AND CENTRAL PLAINS AND SUBSEQUENT TRANSPORT OF
THIS MOISTURE TO THE NORTHWEST WITH THE LOW LEVEL FLOW, WILL
ENHANCE MIXING RATIOS EVEN FURTHER. CONVECTIVE CLUSTERS WILL
ORIGINATE OFF OF THE VARIOUS TERRAIN FEATURES IN THE LEE OF THE
ROCKIES JUST ABOUT EVERY DAY, AND A FEW OF THESE COULD GROW
UPSCALE INTO LARGER CONVECTIVE CLUSTERS AND AFFECT WESTERN KANSAS
THROUGH AUGUST 6TH. THE TIMING OF THE INDIVIDUAL STORM CLUSTERS
CANNOT BE PREDICTED WITH MUCH ACCURACY IN THIS REGIME. THEREFORE,
20 TO 40% STORM CHANCES WERE GENERALLY MAINTAINED THROUGH AUGUST
6TH. ALSO, GIVEN THE UNCERTAINTY IN ANY CONVECTION AND RESULTANT
COOL OUTFLOW, HIGH TEMPERATURES WILL BE TRICKY AS WELL. OUR BEST
ESTIMATE IS THAT HIGH AND LOW TEMPERATURES WILL BE WITHIN A FEW
DEGREES OF CLIMATOLOGICAL VALUES (HIGHS 86-97F AT DODGE CITY, WITH
COOLER READINGS THAN THIS NEAR INTERSTATE 70 AND WARMER READINGS
NEAR THE OKLAHOMA STATE LINE). KEEP IN MIND THAT ANY WIDESPREAD
CLOUD COVER OR RAINFALL COULD LEAD TO MUCH COOLER TEMPERATURES ON
ANY GIVEN DAY.
AFTER AUGUST 6TH, THE VARIOUS MODELS ARE ADVERTISING A STRONG UPPER
LEVEL LOW TO DROP SOUTHWARD OUT OF CANADA INTO THE GREAT LAKES
REGION. THE ASSOCIATED COLD FRONT COULD BRING MUCH COOLER AIR INTO THE
CENTRAL PLAINS BY LATE NEXT WEEK, WITH HIGHS POSSIBLY FALLING INTO
THE 70S DEPENDING ON THE AMOUNT OF ACCOMPANYING CLOUD COVER AND
PRECIPITATION BEHIND THE FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1202 AM CDT WED JUL 31 2013
AREAS OF GROUND FOG WITH VSBYS LESS THAN 1 MILE ARE POSSIBLE
THROUGH 14-15Z, THEN EXPECT VFR CONDITIONS. A COMPLEX OF
THUNDERSTORMS IS THEN FORECAST TO DEVELOP NEAR KGCK BY 23-02Z AND
DROP SOUTH WITH SOME SEVERE. KDDC AND KHYS MAY BE CLOSE OR GET
INTO THE ACTIVITY LATER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 93 71 97 / 30 30 30 20
GCK 68 94 71 96 / 40 30 30 20
EHA 67 95 71 97 / 40 30 30 20
LBL 69 95 72 97 / 40 30 30 20
HYS 68 92 71 89 / 30 40 40 20
P28 70 94 73 93 / 10 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ031-046-
065-066-079>081-089-090.
&&
$$
UPDATE...SUGDEN
SHORT TERM...BURKE
LONG TERM...FINCH
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS JACKSON KY
348 AM EDT WED JUL 31 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 340 AM EDT WED JUL 31 2013
A SHORTWAVE IS CURRENTLY WORKING THROUGH THE OH VALLEY REGION IN
WEST NORTHWEST FLOW...BUT IS PRODUCING ONLY LIGHT RAIN SHOWERS
LOCALLY. A RIDGE OF HIGH PRESSURE WAS CENTERED OVER THEE SOUTHERN
ROCKIES WITH AN UPPER LEVEL LOW AND TROUGH CONTINUING TO EXIT THE
NORTHEASTERN CONUS INTO THE MARITIMES. ALSO IN THE NORTHERN
STREAM...A SHORTWAVE TRACKING NEAR THE US/CANADIAN BORDER IS
APPROACHING THE UPPER MS VALLEY AND WESTERN ONTARIO. HEAVIER
PRECIPITATION THUS FAR HAS BEEN CONFINED TO SOUTHERN MIDDLE AND
EASTERN TN AND THE NORTHERN GULF COAST STATES. THERE HAS ALSO BEEN A
SLIGHT INCREASE IN CONVECTION OVER WESTERN KY.
THE SHORTWAVE NOW WORKING THROUGH THE OH VALLEY AND INTO THE
APPALACHIAN REGION AND THE SHORTWAVE WORKING TOWARD THE WESTERN GREAT
LAKES WILL EVENTUALLY BECOME A BIT MORE PHASED BY THUS AND LEAD TO A
RETURN TO A MORE AMPLIFIED EASTERN/NORTHEASTERN CONUS THROUGH AND
ROCKIES/PLAINS RIDGE. MEANWHILE A SFC LOW IS LAGGING THE UPPER LEVEL
SHORTWAVE WORKING THROUGH THE OH VALLEY. THIS LOW WILL DRIFT THROUGH
THE LOWER OH VALLEY REGION AND REACH CENTRAL KY THIS EVENING...EVENTUALLY
BECOMING DIFFUSE AND MORE OR LESS MERGING WITH A COLD FRONT ASSOCIATED
WITH THE TROUGH WORKING THROUGH ONTARIO AND THE GREAT LAKES REGION
TONIGHT AND INTO THURSDAY. THE SFC COLD FRONT SHOULD CROSS THE CWA ON
THURSDAY.
THE 0Z NAM AND THE 4Z HRR GENERALLY INDICATE REDEVELOPMENT OF
STRONGER CONVECTION THAN THE LIGHT SHOWERS CURRENTLY OVER THE CWA
TOWARD DAWN AND THEN WORK THIS INTO EASTERN KY THIS MORNING AND INTO
THIS AFTERNOON. THE NAM HAS BULLSEYE OF QPF OVER THE LAKE CUMBERLAND
REGION...BUT MUCH OF THE OTHER GUIDANCE HAS HIGHER QPF NEAR THE TN
BORDER...AND IS NOT NEARLY AS MUCH. CONFIDENCE IN THE EVOLUTION OF
THIS CONVECTION IS BELOW AVERAGE...BUT THE MODEL CONSENSUS IS THAT
BEST CHANCES SHOULD BE ACROSS THE SOUTH TODAY. THE 5Z HRRR HAS THROWN
A BIT MORE UNCERTAINTY INTO THE PICTURE...ESPECIALLY ACROSS THE NORTH
WITH IT SUGGEST COULD LARGELY REMAIN DRY.
WE HAVE OPTED TO GO VERY CLOSE TO HPC QPF WHICH LED TO LOWER AMOUNTS
THAN THE NAM OVER THE SOUTH WITH THE HIGHEST POPS OVER THE SOUTHERN
CWA. HOWEVER...THIS STILL YIELDS NEARLY AN INCH OF RAIN THROUGH
TONIGHT. ALTHOUGH A SHORTWAVE CURRENTLY WORKING THROUGH THE OH VALLEY
AND ANOTHER UPSTREAM WILL WORK ACROSS THE AREA THIS AFTERNOON AND THE
SFC LOW WILL GRADUALLY APPROACH THE AREA...CLOUD COVER SHOULD LIMIT
OVERALL INSTABILITY. THE CLOSEST LIGHTNING AT PRESENT IS OVER WESTERN
KY. THUS WE HAVE KEPT COVERAGE OF THUNDER AT ISOLATED TO SCATTERED
LEVELS THROUGH THIS EVENING WITH HIGHER COVERAGE OF SHOWERS.
HOWEVER... CHANCES FOR CONVECTION WILL LINGER THROUGH MOST OF THE
PERIOD...UNTIL LATE ON THU WHEN A COLD FRONT WILL SWEEP THE DEEPER
MOISTURE EAST AND SOUTHEAST OF THE AREA.
MOS GUIDANCE WAS TOO WARM WITH HIGHS ON TUE AND WE HAVE WENT ON THE
COLDER END OF GUIDANCE FOR MAX T TODAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 AM EDT WED JUL 31 2013
MODELS ARE AGREEING A BIT MORE HEADING INTO THE UPCOMING
WEEKEND...SO CONFIDENCE IN THE FORECAST IS INCREASING. STARTING
THURSDAY NIGHT...HIGH PRESSURE WILL BE BUILDING INTO THE
REGION...SETTING UP A DRY AND PLEASANT END TO THE WEEK. A SHORTWAVE
TROUGH WILL THEN DRAG A SURFACE WARM FRONT BACK TO THE NORTHEAST
LATE FRIDAY NIGHT INTO SATURDAY WITH ISENTROPIC ASCENT DEVELOPING
OVER THE REGION. THIS WILL YIELD THE POTENTIAL FOR A WET PERIOD ON
SATURDAY...AS THE WARM FRONT STALLS OVER THE AREA. A SECONDARY
SHORTWAVE PUSHING ACROSS THE GREAT LAKES WILL THEN DRAG A COLD FRONT
SOUTHWARD ACROSS THE OHIO RIVER VALLEY SATURDAY NIGHT INTO EARLY
SUNDAY...WITH ANOTHER PERIOD OF UNSETTLED WEATHER EXPECTED. THIS
FRONTAL BOUNDARY WILL GET SHOVED SOUTHWARD ON SUNDAY WITH DRY
WEATHER RETURNING TO FINISH OUT THE WEEKEND. HOWEVER...THE ACTIVE
WEATHER WILL CONTINUE AS ANOTHER SHORTWAVE PUSHES EAST INTO THE AREA
ON MONDAY...BRINGING ANOTHER ROUND OF SHOWERS AND PERHAPS A
THUNDERSTORM TO THE AREA. DRIER WEATHER MAY RETURN BY TUESDAY AND
WEDNESDAY...BUT GIVEN THE TROUGH OVER THE REGION...ADDITIONAL WAVES
OF UNSETTLED WEATHER COULD IMPACT THE REGION. HIGHS THROUGH THE
PERIOD WILL BE A TOUCH BELOW NORMAL WITH A GENERAL TROUGH OVER THE
EASTERN US...KEEPING TEMPERATURES UNUSUALLY COOL FOR THIS TIME OF
YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 210 AM EDT WED JUL 31 2013
THE AREA OF RAIN CURRENTLY OVER THE REGION HAS BEEN SO LIGHT THAT
CONDITIONS HAVE GENERALLY REMAINED VFR. IF MORE INTENSE SHOWERS
DEVELOP TO OUR WEST AFTER ABOUT 8Z AND ENTER THE CWA AROUND DAWN AND
MOVE ACROSS THE AREA ON WED...AVIATION CONDITIONS SHOULD GRADUALLY
WORSEN INTO THE MVFR RANGE FOR VIS AND OR CIGS. A BIT OF IFR
IS POSSIBLE IN ANY THUNDERSTORMS AFTER 15Z. THE PCPN THREAT SHOULD
DIMINISH LATE IN THE PERIOD AS A COLD FRONT APPROACHES THE AREA.
HOWEVER...MVFR MAY BE POSSIBLE LATE IN THE PERIOD ALONG THE FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
211 AM EDT WED JUL 31 2013
.UPDATE...
ISSUED AT 200 AM EDT WED JUL 31 2013
ALTHOUGH THE NAM AND HRRR GUIDANCE SUGGEST SOME ELEVATED CONVECTION
MAY OCCUR TOWARD INSTABILITY APPEARS TOO LIMITED FOR ANY THUNDER FOR
THE REMAINDER OF THE NIGHT. THE HRRR WEAKENS THIS CONVECTION MOVING
INTO THE JKL CWA DURING WED MORNING AND GENERALLY SHIFTS IT INTO TN.
OPTED TO REMOVE THUNDER FROM THE FORECAST FOR THE REST OF THE
OVERNIGHT HOURS. TEMPERATURES IN A FEW WESTERN LOCATIONS PARTICULARLY
THE CUMBERLAND VALLEY WERE RUNNING A LITTLE COOLER THAN THE PREVIOUS
FORECAST AND TEMP AND DEWPOINT GRIDS HAVE BEEN ADJUSTED ACCORDINGLY.
THE 0Z NAM QPF SEEMS A BIT TOO HIGH OVER THE SOUTH EARLY ON WED AND
UNLESS SOME THUNDERSTORMS DO DEVELOP AND TRAIN A BIT EVEN THE 22Z HPC
QPF SEEMS A BIT OVERDONE AS WELL. CONFIDENCE IN THE HIGHER VALUES IS
NOT ALL THAT HIGHS SO 12Z TO 18Z QPF FOR WED WAS TONED DOWN A BIT
FROM THE INHERITED FORECAST.
UPDATE ISSUED AT 1045 PM EDT TUE JUL 30 2013
DID A QUICK UPDATE TO THE GRIDS AND ZONES TO FINE TUNE RAIN CHANCES
THROUGH THE NIGHT AS WELL AS TO PUSH BACK ANY THUNDER CHANCES UNTIL
CLOSER TOWARDS DAWN...FOR MOST LOCATIONS. ALSO TWEAKED TEMPS AND
DEWPOINTS PER THE LATEST OBS AND TRENDS. UPDATES HAVE BEEN SENT TO
THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 645 PM EDT TUE JUL 30 2013
22Z SFC ANALYSIS SHOWS THAT OUR COOL HIGH PRESSURE IS NOW RETREATING
TO THE EAST IN THE FACE OF A DEVELOPING AREA OF LOW PRESSURE LIFTING
INTO THE MID MISSISSIPPI VALLEY. AHEAD OF THIS LOW...AN MCV IN THE
MID LEVELS OF THE ATMOSPHERE IS PUSHING EAST INTO KENTUCKY THIS
EVENING. THIS IS HELPING TO SUSTAIN A LARGE AREA OF LIGHT TO MODERATE
RAIN SLOWLY CROSSING THE BLUEGRASS STATE. FOR EAST KENTUCKY...SO
FAR...THIS HAS MEANT LITTLE MORE THAN SOME VIRGA OVER THE CUMBERLAND
VALLEY BUT MORE SUBSTANTIAL SHOWERS ARE NOT FAR OUT. EXPECT THE RAIN
TO OVERTAKE THE CWA THROUGH THE LATE EVENING AND EARLY MORNING HOURS
FROM WEST TO EAST. A STRAY BOLT OF LIGHTNING WILL BE POSSIBLE THROUGH
THE NIGHT ALONG WITH HEAVIER AMOUNTS OF RAIN FOR THE SOUTHEAST PARTS
OF THE AREA PER THE LATEST NAM12 AND HRRR GUIDANCE. HAVE UPDATED THE
FIRST TWO PERIODS OF THE FORECAST TO REFLECT THIS. ALSO ADJUSTED
TEMPERATURES AND DEWPOINTS THROUGH THE NIGHT IN LINE WITH THE LATEST
THOUGHTS ON PCPN CHANCES AND QPF. UPDATES HAVE BEEN SENT TO THE NDFD
AND WEB SERVERS...ALONG WITH A FRESHENED SET OF ZONES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 250 PM EDT TUE JUL 30 2013
SFC WARM FRONT FROM SRN ILL TO MIDDLE TENN AND SLOWLY CREEPING TO THE
NE. CURRENT PCPN APPEARS TO BE EDGING INTO MIDDLE KY. CURRENT CLOUD
COVER OVER ERN KY IS HIGH CI WITH SOME MID LEVEL CLOUDS AND VIRGA
EDGING INTO OUR SWRN COUNTIES. SKEW-T INDICATES A WEAK SPEED MAX AT
50H COINCIDENT WITH A VERY MOIST LAYER ABOVE AND VERY DRY BELOW THAT
MAX. SHOULD SEE A GRADUAL MOISTENING OF THE LOWER LAYERS AND A
LOWERING OF THE CEILING HEIGHTS THIS EVENING INTO TONIGHT.
MODELS INDICATE THE PCPN ENTERING THE I-75 CORRIDOR AROUND MIDNIGHT
TONIGHT AS A COLD FRONT SWEEPS ACROSS THE OHIO VALLEY OVERNIGHT. THE
COLD FRONT WILL PROVIDE THE BEST RAINFALL EARLY THU BEFORE BECOMING
NEARLY STATIONARY JUST EAST OF THE APPALACHIAN MTNS WITH SEVERAL
SHORT WAVES DROPPING FROM THE GREAT LAKES TO REINFORCE THE ERN TROF.
EACH SHORT WAVE WILL BRING ANOTHER QUICK SHOT OF PCPN BUT THE
RAINFALL ON WED NITE AND THU WILL NOT BE AS HEAVY OR WIDESPREAD WITH
THE FRONTAL BNDRY HAVING WRUNG MUCH OF THE AVAILABLE MOISTURE FROM
THE AIR. THE LAST OF THE SHRA SHOULD EASE OUT OF THE STATE ON THU
MORNING WITH THE SKY BEGINNING TO CLEAR THU AFTERNOON.
CLOUD COVER AND AN INCREASE IN DEW POINTS WILL HOLD TEMPS TONIGHT IN
THE LOWER 60S. WITH THE INFLUX OF RAIN ON WED BEFORE DROPPING TO THE
MID 60S WED NITE. THEN WITH AN END TO THE RAIN AND SOME HELP FROM
BREAKS IN THE CLOUD COVER ON THU AFTERNOON...TEMPS COULD SHOOT UP TO
THE LOWER 80S. THU HIGHS ARE PREDICATED ON SOME CLEARING...SO IF THE
CLOUDS REMAIN THE HIGHS WILL NECESSARILY NEED TO BE LOWERED SOME.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 251 PM EDT TUE JUL 30 2013
THE MODELS START OFF IN VERY GOOD AGREEMENT WITH UPPER TROUGHS OVER
BOTH COASTS AND AN UPPER RIDGE OVER THE ROCKIES. WITH THIS TYPE OF
PATTERN...SYSTEMS FROM THE WEST COAST ARE BEING BLOCKED BY THE RIDGE
FROM MOVING ACROSS THE AREA. ALL THE SYSTEMS THAT COME THROUGH THE
AREA COME FROM ARES FAR TO THE NORTH AND THEN MOVE DOWN THE BACK OF
THE UPPER TROUGH. THIS SHOULD RESULT IN CONTINUED COOL WEATHER FOR
THIS TIME OF YEAR. BY SUNDAY...THE TIMING OF THE SYSTEMS STARTS TO
BECOME LESS CERTAIN AS THE MODELS DIFFER IN THE TIMING OF THE SHORT
WAVES MOVING DOWN THE BACK SIDE OF THE TROUGH. THE GFS HAS A FRONT
MOVING THROUGH THE AREA ON SATURDAY AND HAS THE LAST OF THE
PRECIPITATION MOVING OUT OF THE AREA SUNDAY MORNING. THE 00Z ECMWF
IS A LITTLE SLOWER WITH MOVING THE RAIN OUT. THE GFS BRINGS THE NEXT
SYSTEM THROUGH ON TUESDAY WHILE THE THE 00Z ECMWF THEN DOES NOT MOVE
THE NEXT SYSTEM INTO THE AREA UNTIL WEDNESDAY. WILL STAY WITH A
MODEL BLEND FOR TIMING AND THEN NUDGE IT TOWARD THE NEW ECMWF
FORECAST WHEN IT COMES IN AT 3 PM. FOR TEMPERATURES STAYED CLOSE
STAYED A BIT COOLER THAN MOS...BUT DID NOT MAKE ANY LARGE CHANGES
FROM THE CONSENSUS MODEL BLEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 210 AM EDT WED JUL 31 2013
THE AREA OF RAIN CURRENTLY OVER THE REGION HAS BEEN SO LIGHT THAT
CONDITIONS HAVE GENERALLY REMAINED VFR. IF MORE INTENSE SHOWERS
DEVELOP TO OUR WEST AFTER ABOUT 8Z AND ENTER THE CWA AROUND DAWN AND
MOVE ACROSS THE AREA ON WED...AVIATION CONDITIONS SHOULD GRADUALLY
WORSEN INTO THE MVFR RANGE FOR VIS AND OR CIGS. A BIT OF IFR
IS POSSIBLE IN ANY THUNDERSTORMS AFTER 15Z. THE PCPN THREAT SHOULD
DIMINISH LATE IN THE PERIOD AS A COLD FRONT APPROACHES THE AREA.
HOWEVER...MVFR MAY BE POSSIBLE LATE IN THE PERIOD ALONG THE FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...DUSTY
LONG TERM...JJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 AM EDT WED JUL 31 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 314 PM EDT TUE JUL 30 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A WNW FLOW ALF
OVER THE NRN TIER CONUS AND OVER THE UPR LKS BTWN A SPRAWLING RDG
OVER THE S AND A TROF OVER CNTRL CANADA. SOME SCT -SHRA ASSOCIATED
WITH A DISTURBANCE THRU ONTARIO JUST N OF LK SUP IMPACTED UPR MI
EARLIER IN THE DAY...BUT THE ARRIVAL OF MUCH DRIER AIR ALF SHOWN
BEST ON THE 12Z MPX...ABERDEEN SDAKOTA...AND BISMARCK RAOBS IS
CAUSING THE SHRA TO DIMINISH THIS AFTN. STRONG CAPPING DEPICTED ON
THE LOCAL AND THOSE UPSTREAM RAOBS HAS PREVENTED ANY TS. THE CLDS
ARE A BIT MORE RESILIENT ESPECIALLY OVER THE W WITH LINGERING LLVL
MSTR SHOWN ON THOSE UPSTREAM RAOBS. FARTHER TO THE W...ANOTHER
SHRTWV MOVING FM THE NRN ROCKIES INTO THE NRN PLAINS IS INTERACTING
WITH THE MUCH MOISTER ENVIRONMENT SHOWN ON THE 12Z GLASGOW MT RAOB
AND CAUSING MORE SHRA/TS TO EXPAND INTO THE NRN PLAINS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/IMPACT ON TEMPS
TNGT AND THEN SHRA/TS CHCS LATE TNGT THRU WED ASSOCIATED WITH
DISTURBANCE NOW ROLLING INTO THE NRN PLAINS.
TNGT...WITH DRYING ALF AND LOSS OF DAYTIME HEATING...ANY LINGERING
DIURNAL -SHRA SHOULD DIMINISH ANRD 00Z...WITH THE MORE PERSISTENT
ACTIVITY ALONG DECAYING LK BREEZE BNDRY OVER THE NCENTRAL. SUPRISED
SEVERAL OF THE MODELS GENERATE PCPN THRU MUCH OF THE NGT. BUT
CONSIDERING THE MAGNITUDE OF THE DRYING SHOWN ON THE UPSTREAM RAOBS
AND LACK OF ANY SGNFT H85 THETA E ADVCTN...SUSPECT THE REST OF THE
EVNG WL FEATURE DRY WX WITH THIS MID LVL DRY AIR DOMINATING. MORE
SHRA MAY ARRIVE OVER THE W LATER TNGT AS DPVA/HGT FALLS IN ADVANCE
OF NEXT SHRTWV PUSH INTO THE AREA AND ERODE MID LVL CAPPING AND
MOISTEN THE MID LVLS. BUMPED UP POPS OVER THE W TO ACCOUNT FOR MODEL
TRENDS TOWARD FASTER ARRIVAL OF THIS DYNAMIC FORCING.
WED...SHRA/EMBEDDED TS OVER THE W IN THE MRNG IN ADVANCE OF INCOMING
SHRTWV/ATTENDANT COLD FNT WL MOVE E THRU THE DAY WITH FAIRLY POTENT
DPVA/DEEP LYR QVECTOR CNVGC. A GOOD AMOUNT OF CLD COVER/FCST NEUTRAL
TO NEGATIVE H85 THETA E ADVCTN WL LIMIT HOW MUCH DEEPER LAPSE RATES
CAN DESTABILIZE...AND MODEL FCST SDNGS SHOW NARROW/SKINNY CAPE
DESPITE MUCAPE AS HI AS 1000J/KG. SO SUSPECT SEVERE WX THREAT WL BE
QUITE LIMITED DESPITE STRENGTH OF SHRTWV/12HR HGT FALLS UP TO 60M
DURING DIURNAL HEATING TIME/DEEP LYR SHEAR 30-35KTS...ESPECIALLY
SINCE MODELS HAVE TRENDED FASTER WITH THE SHRTWV PASSAGE/COLD FROPA.
THE BETTER CHC FOR MORE WDSPRD AND STRONGER SHRA/TS WOULD BE OVER
THE E...WHERE LATER ARRIVAL OF THE FNT MIGHT ALLOW FOR MORE DIURNAL
ENHANCEMENT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 241 PM EDT TUE JUL 30 2013
MUCH OF THIS TIME PERIOD WILL BE PLAGUED BY AFTERNOON SHOWERS OR
POSSIBLE THUNDERSTORMS ACROSS MAINLY CENTRAL UPPER MICHIGAN...THANKS
TO PERSISTENT NW FLOW ALOFT USHERING IN NEARLY DAILY DISTURBANCES
THAT WILL BE ENHANCED BY DAYTIME HEATING AND POTENTIAL LAKE BREEZES.
EXPECT A NEARLY STEADY FORECAST OF THROUGH TUESDAY OF LOWS IN THE
50S /WITH A FEW UPPER 40S/ AND HIGHS IN THE 60S TO LOW 70S /WARMEST
SOUTH CENTRAL/.
BY WEDNESDAY EVENING THE MAIN SYSTEM WILL BE ON ITS WAY OUT...WITH
THE 500MB LOW SET UP ACROSS NORTHERN ONTARIO AND A BROAD TROUGH
EXTENDING FROM ALBERTA AND SASKATCHEWAN THROUGH WI AND MI. THE SLOW
MOVING SFC LOW SHOULD BE OVER N ONTARIO...WITH A COLD FRONT
EXTENDING ACROSS E UPPER MI. BEHIND THE FRONT...LIGHT W TO WNW FLOW
WILL BE THE RULE NEAR THE SFC...WITH THE SFC TROUGH SLOWLY EXITING
EASTWARD BY THE END OF THE WORK WEEK. A SECONDARY COLD FRONT/TROUGH
WILL CROSS THE REGION LATE THURSDAY AFTERNOON...WITH ANOTHER GOOD
CHANCE OF SHOWERS OR THUNDERSTORMS MAINLY INLAND FROM LAKE SUPERIOR.
HIGH PRESSURE WILL ENCOMPASS UPPER MI AND LAKE SUPERIOR LATE FRIDAY
THROUGH SUNDAY. THE GFS AND ECMWF ARE IN A SLIGHT DISAGREEMENT BY
SUNDAY NIGHT...WHICH CONTINUES THROUGH THE REMAINDER OF THE FCST
PERIOD. IT ALL STEMS FROM TIMING OF THE NEXT WAVES SWINGING IN FROM
THE NW...WITH THE GFS BUILDING IN A MORE ROBUST RIDGE AT THE SFC AND
ALOFT SUNDAY NIGHT. EXPECT WAA TO BEGIN OVER THE W LATE
SUNDAY...WITH HIGH CLOUDS ENCROACHING IN ADVANCE OF LOW PRESSURE
ORGANIZING ACROSS THE PLAINS STATES. WE MAY END UP DRY ON
MONDAY...AS THE 30/00Z IS MUCH WEAKER AND SLOWER WITH THE LOW WHEN
COMPARED TO THE 30/12Z GFS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 138 AM EDT WED JUL 31 2013
VFR CONDITIONS SHOULD PREVAIL THRU THE NIGHT AT KIWD/KCMX/KSAW.
HOWEVER...THERE IS A SMALL POTENTIAL FOR FOG OR LOWER CLOUDS TO
DEVELOP AS CURRENT STRATOCU DECK BREAKS UP SOME. WILL BE SOMETHING
TO MONITOR. WHILE THE NIGHTTIME HRS SHOULD BE DRY...THERE MAY BE A
FEW -SHRA/SPRINKLES AROUND THE AREA...PARTICULARLY IN CNTRL UPPER
MI. COVERAGE SHOULD BE TOO LOW TO INCLUDE MENTION IN FCST. BETTER
OPPORTUNITY FOR SHRA WILL ARRIVE THIS MORNING INTO THE AFTN AS COLD
FRONT SWINGS THRU THE UPPER LAKES. ANY HEAVIER SHRA COULD BRING MVFR
CONDITIONS. THERE MAY BE A FEW TSRA AS WELL...ESPECIALLY ACROSS
CNTRL UPPER MI...BUT TSRA WILL DEPEND ON AMOUNT OF DAYTIME HEATING
TO GENERATE INSTABILITY. FOR NOW...ONLY INCLUDED VCSH AT KCMX/KIWD
DUE TO BETTER INSTABILITY DEVELOPING S AND E OF THOSE TERMINALS.
OPTED TO INCLUDE VCTS AT KSAW WITH FRONT ARRIVAL COINCIDING WITH
DAYTIME HEATING. PCPN CHC WILL END NW TO SE DURING THE AFTN WITH VFR
CONDITIONS INTO THE EVENING HRS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 314 PM EDT TUE JUL 30 2013
EXPECT WINDS NO HIGHER THAN 20 KTS THIS FORECAST PERIOD WITH A WEAK
PRESSURE GRADIENT DOMINATING THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
356 AM CDT WED JUL 31 2013
.SHORT TERM...TODAY THROUGH THURSDAY.
AT 330 AM...ISOLATED SHOWERS AND THUNDERSTORMS WERE DEVELOPING
ACROSS THE REGION. THE STRONGEST STORM WAS MOVING QUICKLY TOWARD
THE WESTERN PORTION OF THE CWA...SPECIFICALLY CASS COUNTY.
TEMPERATURES AT 3 AM RANGED FROM THE MID 50S TO THE MID 60S.
PATCHY FOG ALSO WAS FOUND ACROSS THE CWA. THERE HAS BEEN SOME
IMPROVEMENT AS THICKER CLOUDS HAVE MOVED IN.
THE MAIN FOCUS FOR TODAY IS ON THUNDERSTORM POTENTIAL. A FRONTAL
BOUNDARY WILL CONTINUE TO MOVE TO THE SOUTH AND EAST ACROSS THE
REGION TODAY...WITH ISOLATED THUNDERSTORMS DEVELOPING ALONG AND
AHEAD OF THE FRONT. IN ADDITION...ANOTHER TROUGH WILL FOLLOW
BEHIND THE FRONT. TOUGH TO PUT TOO MUCH INTO TIMING TODAY BUT
THINK ISOLATED WORDING WILL COVER IT WELL. IN ADDITION...THERE
SHOULD BE SOME DIURNAL SHOWERS AND STORMS ACROSS THE NORTH BY THIS
AFTERNOON. THE HRRR...4 KM NMM AND RAP ARE ALL INDICATING THAT
THERE WILL BE SOME DEVELOPMENT DUE TO DAYTIME HEATING WITH SOME
WEAK INSTABILITY BY THIS AFTERNOON. THE BEST CHANCE FOR SEEING
SOME STRONGER STORMS IS IN EC MN AND NW WI...WHERE SPC HAS A 5
PERCENT WIND AND HAIL CONTOUR.
WITH THE LOSS OF DAYTIME HEATING WE SHOULD SEE A QUICK DEMISE TO
THE SHOWERS AND THUNDERSTORMS TONIGHT. WITH COLD AIR ALOFT AND AN
UPPER LEVEL SHORTWAVE AND VORT MAX...WE SHOULD SEE MORE DIURNAL
ACTIVITY ON THURSDAY SO WILL CONTINUE WITH SMALLER POPS ACROSS
MUCH OF THE AREA BY AFTERNOON.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
THURSDAY NIGHT A WEAK TROUGH AXIS CONTINUES TO MOVE ACROSS THE
FORECAST AREA AS A SHORTWAVE MOVES THROUGH THE UPPER FLOW. SOME
MODELS ARE GENERATING A NICE MCS OVER THE FORECAST AREA AND THEN
DRIVING IT SOUTHEAST ALONG WITH THE UPPER LEVEL FLOW. BETTER
INSTABILITY WILL BE FARTHER SOUTH ALONG THE STRONGER BAROCLINIC ZONE
ACROSS SOUTH DAKOTA EXTENDING INTO IOWA...SO AM NOT TERRIBLY EXCITED
ABOUT ANYTHING SIGNIFICANT THURSDAY NIGHT...BUT AM CARRYING SOME
CHANCE POPS FOR AT LEAST A PORTION OF THE AREA. MUCH IS GOING TO
DEPEND ON THE TIMING OF THE SHORTWAVE WHICH IS HANDLED IN VARYING
WAYS BY THE MODELS THIS MORNING. MIN TEMPS TO BE KEPT MILD BY EXTRA
CLOUD COVER...AND WILL BE MAINLY IN THE 50S.
FRIDAY THROUGH MOST OF SUNDAY A STRONG SURFACE RIDGE BUILDS INTO
THE REGION. ON FRIDAY BEFORE THE RIDGE GETS FIRMLY ESTABLISHED HAVE
SOME SLIGHT CHANCE POPS AS CYCLONIC FLOW ALOFT INTERACTS WITH SOME
LINGERING LOW LEVEL MOISTURE AND CONVERGENCE. TEMPERATURES COOL OFF
FAIRLY SIGNIFICANTLY BY FRIDAY NIGHT AND SATURDAY...WITH ANOTHER
NIGHT WITH SOME 40S ALL THREE NIGHTS...AND HIGHS ONLY IN THE LOW 70S
SATURDAY.
LATE SUNDAY...SUNDAY NIGHT AND MONDAY THINGS BEGIN TO SHIFT AS ANOTHER
SHORTWAVE DIVES THROUGH THE UPPER LEVEL FLOW AND THE SURFACE RIDGE
SHIFTS EAST OF THE AREA. THIS ALLOWS THE BAROCLINIC ZONE TO SHIFT
NORTH INTO SOUTH DAKOTA AND SOUTHERN MINNESOTA...AND WITH THE UPPER
LEVEL JET OVER NORTHERN MINNESOTA BY SUNDAY NIGHT AN MCS CAN BE
EXPECTED TO GENERATE SOMEWHERE NEAR OR SOUTH OF THE FORECAST AREA
THAT NIGHT. HOWEVER...AM NOT TOO CONVINCED IT WILL BE THIS FAR
NORTH AND HAVE LIMITED HIGHER POPS TO THE SOUTHERN COUNTIES WITH
LESS ACROSS THE NORTH. TEMPERATURES REMAIN COOL WITH HIGHS IN THE
LOW 70S. THE NORTHWEST FLOW CONTINUES INTO TUESDAY AND THERE ARE
SOME INDICATIONS THAT WE WILL HAVE ANOTHER SHORTWAVE DUE THROUGH
WITH ANOTHER CHANCE OF PRECIPITATION...BUT CONFIDENCE IS NOT VERY
HIGH AT THIS TIME AND HAVE LIMITED POPS. TEMPERATURES TO REMAIN
NEAR OR SLIGHTLY BELOW NORMAL.
&&
.AVIATION.../06Z TAF ISSUANCE/
AN APPROACHING COLD FRONT WILL MOVE THROUGH NORTHEAST MINNESOTA AND
NORTHWEST WISCONSIN OVERNIGHT. IT COULD BRING SOME SHOWERS AND
STORMS TO THE REGION THROUGH EARLY WEDNESDAY AFTERNOON. PATCHY BR
AND FG COULD BRING PERIODS OF LIFR/IFR/MVFR CIGS AND VSBYS TO THE
KHYR/KDLH/KHIB AREAS THROUGH EARLY THIS MORNING...WITH KHYR LIKELY
BEING THE MOST AFFECTED. GUSTY WNW TO NW WINDS WILL DEVELOP BY
THIS AFTERNOON IN THE WAKE OF THE COLD FRONT. VFR CONDITIONS ARE
EXPECTED FOR LATE THIS MORNING THROUGH THIS EVENING.
&&
.POINT TEMPS/POPS...
DLH 76 53 74 55 / 20 20 20 20
INL 71 49 74 51 / 20 20 30 10
BRD 76 52 76 55 / 20 10 10 10
HYR 79 50 76 53 / 20 20 20 30
ASX 76 52 75 54 / 20 20 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....LE
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
354 AM CDT WED JUL 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT WED JUL 31 2013
TODAY AND TONIGHT...HIGH PRESSURE HAS BUILT INTO SCNTL NEB IN WAKE
OF LAST NIGHTS CRUSHING TSTM EVENT. ALL INDICATIONS ARE THE
ATMOSPHERE WILL REMAIN NEARLY QUIET THIS AFTERNOON AND THIS EVENING.
THERE IS PERHAPS THE POTENTIAL FOR DESTABILIZATION THIS AFTN ACROSS
THE CNTL HIGH PLAINS. ISOLATED STORMS COULD DEVELOP ACROSS WRN NEB
WHICH WOULD MOVE EAST AND DISSIPATE IN THE EVENING ACROSS NCNTL NEB.
THERE IS ALSO THE POTENTIAL FOR DESTABILIZATION ACROSS SWRN AND
SCNTL NEB THIS AFTN AND THIS EVENING NORTH OF A SFC FRONT CURRENTLY
LOCATED ACROSS KS AND NERN COLORADO. SPC HAS OUTLOOKED FRONTIER
COUNTY NORTHEAST THROUGH CUSTER AND HOLT COUNTIES IN THEIR DAY 1
OUTLOOK FOR SEVERE TSTM DEVELOPMENT.
FOR THIS MORNING...A CLUSTER OF SHOWERS AND TSTMS ACROSS SWRN SD
COULD SWEEP EAST AND SOUTHEAST THROUGH PARTS OF NWRN AND NCNTL NEB.
THIS IS HIGHLY SPECULATIVE GIVEN THE MODEL DYNAMIC ADJUSTMENT
PROCESS DURING THE FIRST 12 HRS. THE RAP AND HRRR HAVE THEIR OWN
IDEAS. THE RAP SHOWS SCATTERED STORM COVERAGE ACROSS NCNTL NEB WHILE
THE HRRR IS SLOWER AND FARTHER EAST JUST BRUSHING HOLT AND BOYD
COUNTIES. THE FCST IS FOR ISOLATED SHRA/TSTM COVERAGE GIVEN CURRENT
RADAR TRENDS.
TEMPERATURES TODAY ARE ON THE COOL SIDE OF AN ENVELOP OF MID 70S TO
NEAR 90. A BLEND OF MODEL DATA PLUS BIAS CORRECTION YIELDED LOW TO
UPPER 80S FOR HIGHS UNDER SCATTERED AND BROKEN CLOUD COVER.
LASTLY...THE MODELS CONTINUE TO ADVERTISE A LATE NIGHT MCS DROPPING
THROUGH NWRN NEB AROUND 06Z AND THEN PEDDLING EAST AND SOUTHEAST
THROUGH MUCH OF NCNTL NEB BETWEEN 06Z AND 12Z. THE 06Z NAM SHOWS
MODEST ELEVATED CAP AROUND 1000 J/KG AND AN MCS DROPPING MORE SOUTH
THROUGH SCNTL NEB BY 12Z. GIVEN THE TRACK OF THE STORMS TUESDAY
EVENING THIS SOLN HAS SOME CREDIBILITY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 349 AM CDT WED JUL 31 2013
ACTIVE WEATHER TO CONTINUE THROUGH THE PERIOD. A WARM FRONT WILL
EXTEND WEST TO EAST ACROSS THE AREA THURSDAY AND BE THE FOCUS FOR
TSTM DEVELOPMENT. CONTINUED NORTHWEST FLOW ALOFT WILL COMBINE WITH
EAST TO SOUTHEAST WINDS AT THE SFC...PRODUCING FAVORABLE SHEAR FOR
SUPERCELL TSTMS WITH LARGE HAIL AND DAMAGING WIND POTENTIAL. WILL
ALSO HAVE TO WATCH FOR HEAVY RAIN/FLOODING POTENTIAL...AS SOME AREAS
HAVE RECEIVED WELL OVER TWO INCHES OF RAIN THE LAST FEW DAYS.
VALENTINE FOR INSTANCE HAD OVER TWO INCHES OF RAIN JUST LAST
NIGHT.
THE AFOREMENTIONED FRONT WILL REMAIN IN THE AREA FRIDAY THROUGH THE
UPCOMING WEEKEND...AND CONTINUE TO BE THE FOCUS FOR AT LEAST
SCATTERED TSTM DEVELOPMENT. RICH MOISTURE...SHEAR...AND
INSTABILITY...WILL CONTINUE TO BRING THE THREAT FOR A FEW SEVERE
STORMS AS WELL AS LOCALIZED HEAVY RAIN.
BY EARLY NEXT WEEK...HIGH PRESSURE WILL TRY TO NUDGE SOUTH INTO THE
AREA FROM THE NORTHERN PLAINS/CANADA. THIS MAY FORCE THE RICHER
MOISTURE SOUTH INTO KANSAS AND OKLAHOMA...BUT STILLS APPEARS TO BE
ENOUGH MOISTURE IN THE AREA TO CONTINUE SOME SLIGHT AND LOW END
CHANCES FOR TSTM ACTIVITY.
TEMPERATURE WISE...WITH THE FRONT REMAINING IN THE AREA...ALONG WITH
CLOUDS AND PRECIPITATION FROM TIME TO TIME...HIGHS WILL REMAIN
GENERALLY IN THE 80S. OVERNIGHT LOWS WILL BE MILD WITH THE INCREASED
MOISTURE CONTENT IN THE AIR...WITH MOST LOCALS REMAINING IN THE 60S
AT NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1240 AM CDT WED JUL 31 2013
THE HRRR AND RAP MODELS SHOW THE STORMS ACROSS WRN SD SWEEPING
EAST SOUTHEAST THROUGH KVTN AROUND 10Z AND INTO NCNTL NEB THROUGH
12Z. IF THE HRRR IS CORRECT THE STORMS COULD TAKE A MORE SOUTHERLY
TACK AND AFFECT KLBF AROUND 12Z. CURRENT RADAR TRENDS CERTAINLY
SUPPORT A WEAK STORM MOVING THROUGH THE KVTN AREA. THE RAP MODEL
ALSO SHOWS A PERIOD OF MVFR ACROSS NRN NEB THIS MORNING WHICH
SHOULD MIX OUT BY LATE MORNING.
FOR THIS AFTN AND THIS EVENING...THE NAM WOULD SUGGEST ISOLATED TO
SCATTERED TSTM ACTIVITY DEVELOPING ACROSS WRN NEB LATE THIS
AFTERNOON WHICH WOULD MOVE EAST INTO NCNTL NEB DURING THE EVENING
AND WEAKEN.
GIVEN THE VERY VOLITILE ATMOSPHERE IN PLACE...SOME STORMS COULD BE
STRONG OR SEVERE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1253 AM CDT WED JUL 31 2013
.UPDATE...
SCATTERED STRONG TO SEVERE THUNDERSTORMS CONTINUE WITH GOOD
INSTABILITY EXTENDING NORTHWEST THROUGH CUSTER...LINCOLN AND
NORTHWEST...WITH SEVERE THUNDERSTORM WATCH NUMBER 452 TO ALSO
INCLUDE LINCOLN COUNTY. ADDITIONAL CONVECTION DEVELOPING INTO THE
FAR NORTHWEST WITH WATCH VALID UNTIL 11 PM CDT.
&&
.PREV DISCUSSION... /ISSUED 629 PM CDT TUE JUL 30 2013/
UPDATE...
ISSUED AT 620 PM CDT TUE JUL 30 2013
SEVERE THUNDERSTORM WATCH NUMBER 452 CONTINUES WITH
CUSTER...GARFIELD ...HOLT AND WHEELER COUNTIES ADDED AS SEVERE
STORMS CONTINUE TO PUSH SOUTHEAST INTO THE NORTH CENTRAL. STORM
REPORTS HAIL UP TO GOLFBALL AND WIND GUSTS TO 70 MPH.
SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 320 PM CDT TUE JUL 30 2013
SEVERE THUNDERSTORM WATCH IN PLACE FOR NORTHERN AND WEST CENTRAL
NEBRASKA GENERALLY ALONG AND NORTH OF HIGHWAY 2. ONGOING
THUNDERSTORMS OVER NORTHERN NEBRASKA WILL CARRY EAST INTO NORTH
CENTRAL NEBRASKA OVER NIGHT AS THE FRONT OVER CENTRAL SOUTH DAKOTA
MOVES SOUTH TONIGHT. BUFR SOUNDINGS HINT AT REDEVELOPMENT OF FOG
OVER SOUTHWEST NEBRASKA EARLY WEDNESDAY MORNING. HAVE LOWERED
TEMPERATURES ACROSS WESTERN NEBRASKA TONIGHT EXCEPT OVER SOUTHWEST
AND NORTH CENTRAL WHERE CLOUDS AND FOG SHOULD KEEP TEMPERATURES UP.
FOG TO BURN OFF EARLY ON WEDNESDAY BUT COOLER AIR IN BEHIND FRONT
WILL KEEP MUCH OF NORTH CENTRAL NEBRASKA IN COOLER TEMPERATURES.
TEMPERATURES IN LOW 80S NORTH AND UPPER 80S EXTREME SOUTHWEST.
SLIGHT CHANCE OF THUNDERSTORMS IN THE ONEILL AREA THROUGH THE
MORNING AND THEN SHIFT TO SOUTHWEST AND SOUTH CENTRAL LATE AFTERNOON
WITH A WEAK LOW DEVELOPING ALONG THE FRONT OVER SOUTHWEST NEBRASKA.
LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 320 PM CDT TUE JUL 30 2013
A DISTURBANCE WILL MOVE INTO THE FORECAST AREA WEDNESDAY NIGHT. HAVE
INCREASED POPS TO 50 PERCENT PORTIONS OF SHERIDAN AND WRN CHERRY
COUNTY AFTER MIDNIGHT. THE NAM MODEL HAS BEEN CONSISTENT SHOWING
THIS AND THE 12Z GFS IS COMING IN LINE. THIS DISTURBANCE WILL SLOWLY
MOVE SOUTHEAST THURSDAY INTO THURSDAY NIGHT. HAVE INCREASED INTO
LIKELY POPS CENTRAL AND EAST. A WEAK COLD FRONT WEDNESDAY NIGHT WILL
SLOWLY LIFT NORTHEAST AS A WARM FRONT THROUGH THURSDAY
NIGHT...FURTHER AIDING IN LIFT. THERE IS THE POTENTIAL FOR SEVERE
STORMS THURSDAY INTO THURSDAY NIGHT WITH FAVORABLE DEEP LAYER SHEAR
AND INSTABILITY. HIGHS THURSDAY MAINLY IN THE MID 80S.
MAINLY A SLIGHT CHANCE FRIDAY WITH INCREASING 30-40 POPS FRIDAY
NIGHT. CREST OF UPPER RIDGE AXIS TO BE ACROSS NEBR PANHANDLE AND ERN
CO. AFTERNOON STORM DEVELOPMENT TO PUSH EAST IN THE EVENING AND
OVERNIGHT. SIMILAR SETUP THROUGH SATURDAY NIGHT. A NORTHWEST FLOW
SETS UP SUNDAY THROUGH TUESDAY WITH A 20 TO 30 PERCENT CHANCE DAILY.
HIGHS MAINLY IN THE MID 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1240 AM CDT WED JUL 31 2013
THE HRRR AND RAP MODELS SHOW THE STORMS ACROSS WRN SD SWEEPING
EAST SOUTHEAST THROUGH KVTN AROUND 10Z AND INTO NCNTL NEB THROUGH
12Z. IF THE HRRR IS CORRECT THE STORMS COULD TAKE A MORE SOUTHERLY
TACK AND AFFECT KLBF AROUND 12Z. CURRENT RADAR TRENDS CERTAINLY
SUPPORT A WEAK STORM MOVING THROUGH THE KVTN AREA. THE RAP MODEL
ALSO SHOWS A PERIOD OF MVFR ACROSS NRN NEB THIS MORNING WHICH
SHOULD MIX OUT BY LATE MORNING.
FOR THIS AFTN AND THIS EVENING...THE NAM WOULD SUGGEST ISOLATED TO
SCATTERED TSTM ACTIVITY DEVELOPING ACROSS WRN NEB LATE THIS
AFTERNOON WHICH WOULD MOVE EAST INTO NCNTL NEB DURING THE EVENING
AND WEAKEN.
GIVEN THE VERY VOLITILE ATMOSPHERE IN PLACE...SOME STORMS COULD BE
STRONG OR SEVERE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...TLK
LONG TERM...TAYLOR
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1237 AM CDT WED JUL 31 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 246 PM CDT TUE JUL 30 2013
MAIN UPPER LEVEL SCENARIO INCLUDES A PERSISTENT SUBTROPICAL RIDGE
OVER THE SOUTHERN UNITED STATES. SPLIT JET WITHIN QUASI-ZONAL FLOW
IN THE NORTH CONTAINS A SHORTWAVE TROUGH SKIRTING ACROSS THE
NORTHERN PLAINS WHICH SHOULD DEVELOP A LONG ADVERTISED MCS OVER
SOUTH DAKOTA THAT SHOULD MAKE ITS WAY SOUTHEAST...AND COULD JUST
SWIPE THE CWA IN THE NORTH BY LATE TONIGHT. THERE COULD BE ENOUGH
SHEAR TO GET SOME STRONG TO SEVERE WEATHER FROM THE REMNANTS OF THE
EXPECTED MCS. CONVERGENCE ALONG AN APPROACHING COLD FRONT WILL ALSO
INCREASE PRECIPITATION AND SEVERE THUNDERSTORM CHANCES. AS A SIDE
NOTE...SKY COVER IS DIFFICULT TO FORECAST FOR THIS EVENING...AND I
HAVE CURBED THE ENTHUSIASM OF MOST MODELS FOR CLEARING...AS EVEN
THE HRRR HAS SHOWN TOO MUCH OPTIMISM FOR THE CLEARING.
ALSO...MODELS HAVE CONTINUED TO ADVERTISE A FAIRLY STRONG SIGNAL FOR
FOG AND HAVE BEEN PRETTY CONSISTENT AS STRATUS IS FORECAST TO
LOWER UNTIL WE GET DENSE FOG IN OUR EAST. CONFIDENCE IS HIGHER WITH
THE RECENT CONSISTENCY...AND A FAIRLY STRONG SIGNAL IN THE
EASTERN THIRD OF THE CWA PERSISTS...PROMPTING ME TO ISSUE A DENS
FOG ADVISORY FOR LATE TONIGHT INTO WEDNESDAY MORNING.
A COLD FRONT WILL MAKE ITS WAY ACROSS THE CWA FOR WEDNESDAY AND WILL
BE THE FOCUS FOR MORE POSSIBLE SEVERE WEATHER. DEWPOINTS ARE
EXPECTED TO POOL NEAR THE BOUNDARY WITH INCREASED INSTABILITY ALONG
THE FRONT...AND CONTINUED LOW-LEVEL CONVERGENCE. BULK SHEAR WILL
ALSO BE SUFFICIENT ENOUGH FOR SEVERE WEATHER...EVEN IF THERE ARE
LIMITED BREAKS IN SKY COVER. THIS COULD WIND UP BEING A POTENTIALLY
INTERESTING DAY DEPENDING ON THE TIMING OF THE COLD FRONT. KEPT A
CHANCE OF PRECIPITATION NEAR THE FRONT...SIMILAR TO THE PREVIOUS
FORECAST.
BASED TEMPERATURES AND DEWPOINTS ON RECENT MODEL PERFORMANCE AND NOT
MUCH HAS CHANGED FOR THESE FIELDS COMPARED TO THE PREVIOUS
FORECAST...EXCEPT PERHAPS HIGHER DEWPOINTS NEAR THE PROJECTED TIMING
AND PLACEMENT OF THE COLD FRONT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 246 PM CDT TUE JUL 30 2013
GUIDANCE SUGGESTS NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST
OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG TERM FORECAST
PERIOD. WITH MULTIPLE MID LEVEL PERTURBATIONS PERHAPS MOVING OVER
THE AREA WITHIN THE MEAN MID LEVEL FLOW...POPS REMAIN LITTERED
THROUGHOUT MOST ALL OF THE LONG TERM FORECAST PERIOD. OUT OF ALL THE
LONG TERM FORECAST PERIODS...THE HIGHEST CONFIDENCE WITH RESPECT TO
POPS EXISTS DURING THURSDAY AND THURSDAY NIGHT. THESE ARE TIME
PERIODS IN WHICH GUIDANCE SUGGESTS LOW LEVEL THERMAL ADVECTION AND
RESULTANT ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY ALONG THE
315-320K SURFACES...WILL PERSIST. THIS THERMAL ADVECTION...WORKING IN
CONCERT WITH OMEGA FROM MID LEVEL PERTURBATIONS PUSHING
OVERHEAD...SHOULD BE STRONG ENOUGH TO PROMOTE PRECIPITATION
PRODUCTION ACROSS MUCH OF OUR AREA. TAKING A AVERAGE OF THE
NAM...OPERATIONAL GFS...EC...AND SREF-MEAN PROVIDES BETWEEN A
QUARTER INCH AND A HALF INCH OF RAIN ACROSS MUCH OF OUR CWA DURING
THE DAY THURSDAY...AND MUCH OF THE SAME ACROSS OUR EAST THURSDAY
NIGHT. WENT AHEAD AND INCREASED POPS ACROSS MUCH OF OUR CWA THURSDAY
INTO THURSDAY NIGHT AS A RESULT. POPS ALSO CONTINUE ACROSS OUR AREA
FOR THE MOST PART HEADING INTO FRIDAY BEFORE THE PRIMARY AXIS OF
THERMAL ADVECTION FINALLY EXITS THE AREA TO THE EAST. AS MENTIONED
ALREADY...THE POTENTIAL FOR MID LEVEL PERTURBATIONS MOVING OVER THE
AREA SUGGESTS POPS REMAIN WARRANTED ACROSS OUR AREA THROUGH THE
REMAINDER OF THE EXTENDED FORECAST PERIOD. ALLBLEND PROVIDED A
VARIETY OF POPS TO OUR AREA EACH DAY...GENERALLY IN THE 20-40%
RANGE...AND GIVEN THE LOW PROBABILITY OF IMPROVING THE FORECAST
THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART.
INCREASING LOW LEVEL RETURN FLOW AND RESULTANT MOISTURE FLUX INTO
THE AREA SHOULD HELP PROMOTE RESPECTABLE VALUES OF POTENTIAL
INSTABILITY ON THURSDAY...WITH GUIDANCE FROM THE NAM...OPERATIONAL
GFS...AND EC SUGGESTING MUCAPE VALUES RANGING BETWEEN 1500 AND
3500J/KG ACROSS OUR CWA. DEEP LAYER BULK SHEAR VALUES OF 35-45KTS
ARE ALSO FORECAST ACROSS THE AREA ON THURSDAY. THERE IS A CONCERN
THAT EXPANSIVE CLOUD COVER WILL KEEP LOW LEVEL TEMPERATURES ON THE
COOL SIDE WHICH WOULD HELP PRESERVE A LOW LEVEL CAPPING
INVERSION...WHICH WOULD OBVIOUSLY INHIBIT STRONG/DEEP CONVECTION
FROM BEING REALIZED. THAT BEING SAID...IF NEAR-SURFACE BASED
CONVECTION CAN BE REALIZED THURSDAY...THEN CERTAINLY SEVERE WEATHER
WILL BE POSSIBLE AND WILL INTRODUCE SUCH WORDING TO THE HWO. BEYOND
THURSDAY...GUIDANCE SUGGESTS MUCAPE VALUES IN EXCESS OF 2000J/KG
COULD BE REALIZED MOST ANY DAY...BUT AS ALREADY MENTIONED CONFIDENCE
ON WHEN AND WHERE CONVECTION WILL BE REALIZED IS VERY LOW AND AS A
RESULT...WILL MAINTAIN VAGUE SEVERE WEATHER WORDING IN THE HWO FOR
FRIDAY AND BEYOND.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1230 AM CDT WED JUL 31 2013
LOTS OF UNCERTAINTY OVER THE NEXT FEW HOURS AS MODELS ARE HAVING A
TOUGH TIME HANDLING CURRENT CONVECTIVE TRENDS. THAT SAID...WENT
AHEAD AN TRIED TO TIME THE AREA OF SHOWERS AND THUNDERSTORMS NEAR
THEDFORD...AND IF THEY HOLD TOGETHER...THEY SHOULD BE REACHING
KGRI AROUND 08Z. AFTER THIS AREA OF SHOWERS PASS...EXPECT SOME
LIGHT BR DEVELOPMENT JUST BEFORE SUNRISE...AND KEPT MVFR VSBYS AND
CIGS TO ACCOUNT FOR POTENTIAL FOG DEVELOPMENT AS WINDS WILL BE
LIGHT AND SOILS REMAIN FAIRLY SATURATED. THEN AS WE TRANSITION IN
TO THE DAYTIME HOURS WEDNESDAY...EXPECT AN APPROACHING FRONT TO
PROVIDE A TRIGGER FOR ADDITIONAL CONVECTIVE DEVELOPMENT...AND KEPT
A VCTS OR VCSH FROM 31/18Z ONWARD...AS THIS FRONT IS EXPECTED TO
STALL OVER THE HEART OF THE FORECAST AREA THROUGH THE EVENING AND
OVERNIGHT HOURS. OTHER THAN POTENTIAL OUTFLOW WINDS...SYNOPTIC
SCALE FLOW THROUGH THE PERIOD WILL BE LIGHT AND SOMEWHAT VARIABLE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY FROM 4 AM TO 10 AM CDT THIS MORNING FOR
NEZ041-048-049-063-064-076-077-086-087.
KS...DENSE FOG ADVISORY FROM 4 AM TO 10 AM CDT THIS MORNING FOR
KSZ007-019.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...BRYANT
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
447 AM EDT WED JUL 31 2013
.SYNOPSIS...
HIGH PRESSURE PUSHING EAST ACROSS NEW YORK AND PENNSYLVANIA WILL
BRING DRY WEATHER AND SEASONABLE TEMPERATURES TO THE AREA TODAY.
MEANWHILE...MOISTURE ASSOCIATED WITH A PASSING COLD FRONT WILL BRING
A GOOD CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS TONIGHT AND
THURSDAY. LINGERING MOISTURE AND SOMEWHAT UNSTABLE AIR BEHIND THE
FRONT MAY BRING A FEW MORE SHOWERS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE CENTERED OVER NY AND PA EARLY THIS MORNING IS BRINGING
MAINLY CLEAR SKIES TO THE AREA...ALTHOUGH HIGH CLOUDS CONTINUE TO
SKIRT PARTS OF WESTERN NEW YORK AND THE SOUTHERN TIER. THE PRESENCE
OF THE CLOUDS WILL LIKELY LIMIT THE EXTENT OF VALLEY THAT DEVELOPS
BEFORE DAYBREAK...ESPECIALLY BASED ON THE LATEST TREND SHOWN ON THE
IR SATELLITE LOOP WHICH SUGGESTS THAT THE HIGH LEVEL CLOUDS WILL
EXPAND ACROSS THE AREA.
AFTER THE EARLY MORNING FOG DISSIPATES...MID AND HIGH LEVEL CLOUDS
WILL CONTINUE TO SPREAD EAST ACROSS THE AREA TODAY AS THE COLD FRONT
OVER THE PLAINS STATES MOVES EAST INTO THE CENTRAL GREAT LAKES. A
LIGHT SOUTHERLY FLOW AHEAD OF THE FRONT WILL ALLOW TEMPERATURES TO
WARM GENERALLY INTO THE MID AND UPPER 70S DURING THE
AFTERNOON...WITH A FEW SPOTS ACROSS THE SOUTHERN TIER AND FINGER
LAKES POSSIBLY WARMING INTO THE LOWER 80S...DEPENDING ON HOW
EXTENSIVE THE MID LEVEL CLOUDS BECOME.
CONDITIONS WILL DETERIORATE TONIGHT AS MOISTURE DEEPENS AHEAD OF THE
APPROACHING COLD FRONT. THE LATEST GUIDANCE STILL SHOWS STRONG
FRONTOGENETIC FORCING IN THE MID LEVELS OF THE ATMOSPHERE...WHILE A
DECENT UPPER LEVEL JET LIFTS NORTH INTO WESTERN QUEBEC. AS THESE
SOURCES OF FAVORABLE LIFT INTERACT WITH THE INCREASING MOISTURE...
A PERIOD OF MODERATE RAIN IS POSSIBLE...ESPECIALLY DURING THE SECOND
HALF OF THE NIGHT. WHILE THE NAM AND GFS QPF OUTPUTS APPEAR TO BE
SUFFERING FROM CONVECTIVE FEEDBACK...A SOLID HALF INCH OF RAIN IS
POSSIBLE ACROSS PARTS OF WESTERN NEW YORK BEFORE DAYBREAK.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THE LONGWAVE PATTERN THAT WE WILL BE IN DURING THE NEXT WEEK TO TEN
DAYS IS ONE THAT SNOW LOVERS DREAM OF HAVING DURING THE WINTER
MONTHS...BUT ALAS...THEY WILL HAVE TO BE CONTENT WITH COMFORTABLY
COOL LATE SUMMER CONDITIONS. A DEEP TROUGH WILL BE RE-ESTABLISHED
ACROSS EASTERN CANADA AND THE GREAT LAKES REGION AT THE START OF
THIS PERIOD...WITH ADDITIONAL SHORTWAVE ENERGY DIVING INTO ITS BASE
AND THE BUILDING OF A GREENLAND BLOCK INSURING THAT THE HIGH
AMPLITUDE BLOCKING PATTERN WILL BE ANCHORED IN PLACE FOR SOME TIME
TO COME. THIS GENERAL LONGWAVE PATTERN IS STRONGLY SUPPORTED BY ALL
MEDIUM RANGE ENSEMBLE PACKAGES AS WELL AS CPC FORECASTS OF
HEMISPHERIC PROCESSES...LIKE THE NAO AND PNA. MORE ON THIS IN THE
LONG RANGE DISCUSSION BELOW. NOW FOCUSING IN ON THE DETAILS...
A COLD FRONT WILL MARCH ACROSS OUR FORECAST AREA ON THURSDAY...
WITH WIDESPREAD SHOWERS AND POSSIBLY A FEW EMBEDDED THUNDERSTORMS
EXPECTED AS A RESULT. THE GUIDANCE PACKAGES HAVE BEEN DEPICTING A
PROGRESSIVELY EARLIER ONSET OF PCPN FOR THE PAST SEVERAL RUNS...AND
IT SEEMS AS IF THIS IS TIED DIRECTLY TO THE SPEED AND PLACEMENT OF
THE FAVORABLE UPPER LEVEL LIFT SUPPLIED BY A 100KT H25 JET OVER
WESTERN QUEBEC. A 3 TO 5 HOUR PERIOD OF SHOWERS WILL BE ASSOCIATED
WITH THE LIFT FOUND WITHIN THE RR ENTRANCE REGION OF THIS JET...
WITH LINGERING SHOWERS FOUND BACK IN THE VCNTY OF THE LOW LEVEL
FORCING NEAR THE FRONT. THIS WILL BOIL DOWN TO THE BULK OF THE
SHOWERS COMING DURING THE MORNING HOURS FOR THE WRN COUNTIES...AND
DURING THE MIDDAY FOR SITES EAST OF LK ONTARIO. THE SHOWERS WILL
THUS QUICKLY TAPER OFF FROM WEST TO EAST DURING THE COURSE OF THE
AFTERNOON. HAVE RAISED POPS TO 90 REGIONWIDE WITH BASIN AVERAGE QPF
RANGING FROM A QUARTER TO A HALF INCH.
BY THURSDAY EVENING...THE PLUME OF DEEP MOISTURE AHEAD OF THE
FRONT WILL BE RACING ACROSS NEW ENGLAND WHILE THE ACTUAL SFC FRONT
WILL ONLY BE SLOWLY MAKING ITS WAY ACROSS THE EASTERN LAKE ONTARIO
REGION. THIS WILL KEEP THE LIKELIHOOD FOR SOME SHOWERS OVER THE
EASTERN FINGER LAKES AND FOR SITES EAST OF LK ONTARIO...WITH JUST
SPOTTY LIGHT SHOWERS POSSIBLE UNDER A PASSING SHORTWAVE ACROSS THE
WRN COUNTIES. THE TREND WILL DEFINTIELY BE TOWARDS DRIER WEATHER
THOUGH AS LOW LEVEL RIDGING WILL BUILD EAST FROM LOWER MICHIGAN AND
THE OHIO VALLEY.
ANOTHER ISSUE TO KEEP AN EYE ON WILL BE MARGINALLY FAVORABLE
CONDITIONS FOR NUISANCE LAKE EFFECT DURING THE WEE HOURS OF
FRIDAY MORNING. H85 TEMPS ARE FORECAST TO DROP TO AROUND 10C BY
DAYBREAK...AND WITH LK SFC TEMPS IN THE VCNTY OF 22C...THAT WOULD
ONLY SUPPORT WEAK INSTABILITY. THERE WILL ALSO BE LIMITED SYNOPTIC
MOISTURE TO WORK WITH...SO WILL CONTINUE SLGT CHC POPS EAST OF LK
ERIE AND LOW CHC POPS EAST OF LK ONTARIO FOR ANY MINOR LAKE
RESPONSE.
ON FRIDAY AND FRIDAY NIGHT...A SERIES OF WEAK SHORT WAVES WILL
ROTATE THROUGH THE BASE OF THE UPPER LEVEL TROUGH THAT WILL BE
FIRMLY ESTABLISHED OVER THE GREAT LAKES. WHILE THE VAST MAJORITY OF
THIS 24 HOUR PERIOD SHOULD BE RAIN FREE...SCATTERED LIGHT SHOWERS
WILL BE POSSIBLE. THE COMBINATION OF LATE SUMMER HEATING DURING THE
MIDDAY/AFTERNOON WILL COMBINE WITH A SEASONABLY COOL AIRMASS TO
GENERATE LOW LEVEL LAPSE RATES OF 9-10 DEG C/KM...AND THIS ALONG
WITH THE FORCING FROM THE AFOREMENTIONED SHORTWAVE SHOULD BE ENOUGH
TO SUPPORT CHC POPS THROUGH THE EVENING HOURS. THE OVERNIGHT SHOULD
LARGELY BE RAIN FREE...WITH ONLY CHC POPS EAST OF LK ONTARIO FOR
SOME LAKE EFFECT. TEMPS FRIDAY WILL AVERAGE ABOUT 5 DEG F BELOW
NORMAL WITH AFTERNOON HIGHS GENERALLY IN THE MID 70S.
SATURDAY SHOULD BE A FAIRLY NICE DAY...ALBEIT IT SEASONABLY COOL AS
SFC HIGH PRESSURE CENTERED OVER THE CANADIAN PRAIRIES WILL BUILD
SOUTHEAST ACROSS ALL OF THE GREAT LAKES. THIS SHOULD ENCOURAGE
PARTIAL SUNSHINE ACROSS THE REGION WITH H85 TEMPS HOLDING MAX TEMPS
IN THE LOW TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
ALL OF THE THE MEDIUM RANGE ENSEMBLES REMAIN IN STRONG AGREEMENT
THAT THE DEEP...UPPER LEVEL TROUGH WILL HOLD IN PLACE ACROSS EASTERN
NORTH AMERICA THROUGH MUCH IF NOT ALL OF NEXT WEEK. THIS SCENARIO
WILL GUARANTEE THAT WE WILL CONTINUE TO EXPERIENCE BELOW NORMAL
TEMPERATURES...ALTHOUGH NOT ANOMALOUSLY SO AS MERCURY LEVELS WILL
GENERALLY AVERAGING 3-5 DEG F BELOW NORMAL.
IN TERMS OF PCPN...THE BULK OF THIS TIME PERIOD WILL BE RAINFREE.
BESIDES THE LOW CHC FOR NUISANCE LAKE SHOWERS SOUTHEAST OF LK
ONTARIO...CANADIAN HIGH PRESSURE BUILDING ACROSS THE LOWER GREAT
SHOULD PROVIDE THE REGION WITH DRY WEATHER SUNDAY AND MONDAY. THE
ECMWF HAS BECOME THE OUTLIER ON SUNDAY IN THAT IT SUGGESTS THAT A
VIGOROUS SHORTWAVE WILL GENERATE SOME SHOWERS...BUT THIS IS A NEW
SOLUTION AND ONE THAT IS NOT SUPPORTED BY OTHER PACKAGES.
THE POTENTIAL FOR A FAIRLY POTENT SHORTWAVE AND ASSOCIATED SFC WAVE
TO PASS THROUGH THE REGION ON TUESDAY WILL NECESSITATE THE
INTRODUCTION OF CHC POPS.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE CENTERED OVER NY AND PA WILL MAINTAIN VFR CONDITIONS
ACROSS MOST OF THE AREA EARLY THIS MORNING. THE MAIN EXCEPTION WILL
BE ACROSS THE SOUTHERN TIER VALLEYS WHERE RADIATIONAL COOLING MAY
RESULT IN IFR VSBYS IN FOG AT TIMES. THE PRESENCE OF HIGH LEVEL
CLOUDS WILL LIKELY LIMIT THE EXTENT OF THE IFR CONDITIONS.
EXPECT THE VALLEY FOG TO BURN OFF BY MID MORNING. AFTER THIS...MID
AND HIGH LEVEL CLOUDS WILL SPREAD EAST ACROSS THE AREA IN ADVANCE OF
THE NEXT SYSTEM.
OUTLOOK...
THURSDAY...VFR/MVFR WITH SHOWERS AND A FEW SCATTERED THUNDERSTORMS
PRODUCING ASSOCIATED BRIEF IFR.
FRIDAY AND SATURDAY...MAINLY VFR WITH A SMALL CHANCE OF SHOWERS.
SUNDAY...VFR.
&&
.MARINE...
A RELATIVELY WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE ACROSS THE
LOWER LAKES TODAY AND TONIGHT. AFTER A FRONT CROSSES THE LAKES ON
THURSDAY...THE WINDS WILL SWITCH TO THE SOUTHWEST AND PICK UP A
BIT...BUT CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA. MORE IMPORTANTLY...THE FRONT WILL BRING A GOOD
CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS TONIGHT AND
THURSDAY...WITH LOCAL INCREASES IN WIND AND WAVES POSSIBLE.
THE PRESSURE GRADIENT BETWEEN BETWEEN A SURFACE HIGH OVER THE MIDDLE
ATLANTIC STATES AND LOW PRESSURE PUSHING ACROSS HUDSON BAY WILL
CAUSE WESTERLY WINDS TO PICK UP A LITTLE MORE ON FRIDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TJP
NEAR TERM...TJP
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...TJP
MARINE...TJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT WED JUL 31 2013
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL CROSS THE REGION FROM THE
WEST TODAY. A WEAK COLD FRONT WILL APPROACH FROM THE NORTHWEST ON
THURSDAY...THEN STALL OUT OVER THE EASTERN CAROLINAS ON FRIDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 950 PM TUESDAY...
A STATIONARY FRONT REMAINS DRAPED ACROSS EASTERN NC/SC AND EXTENDS
WEST ACROSS GA/AL...WITH WEAK HIGH PRESSURE NOW CENTERED OVER
SOUTHEAST VA. THE FEW SHOWERS AND STORMS IN THE VICINITY OF THE
FRONT HAVE REMAINED NEAR THE COAST THIS EVENING. UPSTREAM...A FAIRLY
PRONOUNCED VORT MAX IS MOVING ACROSS CENTRAL TN...WITH A LARGE AREA
OF MOSTLY STRATIFORM PRECIP OUT AHEAD OF IT...REACHING AS FAR EAST
AS KNOXVILLE. SOME MID/HIGH-LEVEL MOISTENING OVER WESTERN NC CAN BE
SEEN IN THE 00Z KGSO RAOB AND A LARGE VEIL OF CLOUD COVER JUST
REACHING THE WESTERN PIEDMONT. HOWEVER...THERE IS STILL QUITE A BIT
OF DRY AIR BETWEEN 600-800MB AND RAP SOUNDINGS ACTUALLY MAINTAIN
THIS LAYER OF DRY AIR THROUGH THE NIGHT AND INTO WEDNESDAY MORNING.
THE MOST RECENT RUNS OF THE HRRR SUGGEST VERY LIGHT PRECIP OVER THE
WESTERN PIEDMONT AFTER 09-10Z...WHICH MAY END UP JUST BEING
SPRINKLES OR LIGHT RAIN. BASED ON THIS...WILL REMOVE THE MENTION OF
THUNDER FROM THE FORECAST THROUGH MID-MORNING. DEWPOINTS HAVE
SURGED BACK INTO THE UPPER 60S AND LOWER 70S OVER MUCH OF THE
CWA...AND COMBINED WITH INCREASING MID/HIGH CLOUDS...FORECAST LOWS
MOSTLY IN THE UPPER 60S AND LOWER 70S APPEAR ON TRACK.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 PM TUESDAY...
MCS-INDUCED VORT MAX WILL MOVE ACROSS THE AREA ON WEDNESDAY...WITH
CONTINUED MOISTURE RETURN IN STRENGTHENING SOUTHWEST FLOW AHEAD OF
THE MID LEVEL SYSTEM. INSTABILITY WILL BE MARGINAL WITH WEAK
SHEAR...SBCAPE ~500J AND MID LEVEL LAPSE RATES ~5C/KM...BUT THE
VIGOROUS MID LEVEL VORT WILL BE SUPPORTED BY SOME UPPER DIFFLUENCE
WITH A 55-60KT UPPER JET EXITING THE AREA. POP WISE...WILL INTRODUCE
POPS IN THE WEST TOMORROW MORNING...WITH CONVECTION BECOMING LIKELY
ACROSS CENTRAL NC WITH THE TRANSLATION OF THE MID LEVEL SYSTEM AND
DIURNAL INSTABILITY CYCLE. HIGHS WILL BE HAMPERED BY CLOUDINESS...
ESPECIALLY IN THE WEST...WITH LOWER 80S WEST TO SOME UPPER 80S IN
THE EAST WHERE PRECIP WILL BE SLOWER TO ARRIVE.
WE REMAIN IN THE A FAVORABLE MOISTURE ADVECTION REGIME WITH DEEP
SOUTHWEST FLOW TOMORROW NIGHT WITH CYCLONIC FLOW ALOFT. POP CHANCES
WILL REMAIN IN THE HIGH CHANCE TO LIKELY RANGE WITH ONLY SMALL
CHANCES FOR THUNDER GIVEN A LULL IN MID LEVEL DISTURBANCES. MINS
WILL BE MILD GIVEN THE SOUTHERLY FLOW AND CLOUDINESS...68-72.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE MODELS ARE IN VERY GOOD OVERALL AGREEMENT IN THE MEAN MID/UPPER
FLOW PATTERN AND THE RESULTANT SURFACE REFLECTIONS FRIDAY THROUGH
TUESDAY. A MEAN UPPER TROUGH WILL REMAIN ESTABLISHED FROM THE GREAT
LAKES SOUTHWARD THROUGH THE TENNESSEE VALLEY EASTWARD TO THE EASTERN
SEABOARD. THIS WILL KEEP TEMPERATURES IN CHECK FOR THE
CLIMATOLOGICALLY HOTTEST TIME OF THE YEAR. WE WILL ALSO SEE A COUPLE
OF COLD FRONTS THAT WILL BRING ENHANCED CHANCES OF SHOWERS AND
THUNDERSTORMS. NO BIG CHANGE NEEDED TO THE CURRENT FORECAST. THE
HIGHLIGHTS INCLUDE... DRY WEATHER AND BELOW NORMAL TEMPS FRI
AFTERNOON THROUGH SATURDAY. LOWS 63-68. HIGHS MID TO UPPER 80S.
A CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS/STORMS SUNDAY INTO
MONDAY. DRIER AGAIN LATER MONDAY INTO TUESDAY. THEN ANOTHER FRONT
WITH A CHANCE OF CONVECTION AGAIN LATER TUE-WED.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 200 AM WEDNESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS ARE EXPECTED TO PREVAIL THIS MORNING GIVEN WIDESPREAD
CLOUD COVER AND A RELATIVELY LOW LIKELIHOOD OF SUB-VFR FOG OR
STRATUS DEVELOPMENT. LIGHT SHOWER ACTIVITY PROGRESSING EAST INTO THE
FOOTHILLS/PIEDMONT MAY RESULT IN PERIODIC LIGHT RAIN AT THE INT/GSO
TERMINALS THIS MORNING...THOUGH CEILINGS AND VISBYS ARE LIKELY TO
REMAIN VFR. ALTHOUGH SHOWER/THUNDERSTORM ACTIVITY IS EXPECTED TO BE
PRESENT THIS AFT/EVE AND TONIGHT...UNCERTAINTY IS GREATER THAN
NORMAL WITH REGARD TO THE LOCATION/TIMING/COVERAGE OF SUCH
ACTIVITY...AND AT THIS TIME WILL SIMPLY MENTION VCSH AT ALL
TERMINALS.
LOOKING AHEAD:
EXPECT AN INCREASING POTENTIAL FOR SUB-VFR CEILINGS BY SUNRISE THU
MORNING...ALONG WITH A CONTINUED CHANCE FOR SHOWERS AND
THUNDERSTORMS THU INTO THU NIGHT AT ALL TERMINALS AS A WEAK COLD
FRONT APPROACHES FROM THE W/NW. RELATIVELY DRIER AND VFR CONDITIONS
ARE EXPECTED FRI AS THE FRONT STALLS IN THE EASTERN CAROLINAS...
THOUGH CHANCES FOR PRIMARILY AFT/EVE SHOWERS AND STORMS WILL
INCREASE OVER THE WEEKEND AS YET ANOTHER FRONT APPROACHES THE REGION
FROM THE NORTH. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLS
SHORT TERM...MLM
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
201 AM EDT WED JUL 31 2013
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL CROSS THE REGION FROM THE
WEST TODAY. A WEAK COLD FRONT WILL APPROACH FROM THE NORTHWEST ON
THURSDAY...THEN STALL OUT OVER THE EASTERN CAROLINAS ON FRIDAY.
&&
.NEAR TERM /TONIGHT/...
AS OF 950 PM TUESDAY...
A STATIONARY FRONT REMAINS DRAPED ACROSS EASTERN NC/SC AND EXTENDS
WEST ACROSS GA/AL...WITH WEAK HIGH PRESSURE NOW CENTERED OVER
SOUTHEAST VA. THE FEW SHOWERS AND STORMS IN THE VICINITY OF THE
FRONT HAVE REMAINED NEAR THE COAST THIS EVENING. UPSTREAM...A FAIRLY
PRONOUNCED VORT MAX IS MOVING ACROSS CENTRAL TN...WITH A LARGE AREA
OF MOSTLY STRATIFORM PRECIP OUT AHEAD OF IT...REACHING AS FAR EAST
AS KNOXVILLE. SOME MID/HIGH-LEVEL MOISTENING OVER WESTERN NC CAN BE
SEEN IN THE 00Z KGSO RAOB AND A LARGE VEIL OF CLOUD COVER JUST
REACHING THE WESTERN PIEDMONT. HOWEVER...THERE IS STILL QUITE A BIT
OF DRY AIR BETWEEN 600-800MB AND RAP SOUNDINGS ACTUALLY MAINTAIN
THIS LAYER OF DRY AIR THROUGH THE NIGHT AND INTO WEDNESDAY MORNING.
THE MOST RECENT RUNS OF THE HRRR SUGGEST VERY LIGHT PRECIP OVER THE
WESTERN PIEDMONT AFTER 09-10Z...WHICH MAY END UP JUST BEING
SPRINKLES OR LIGHT RAIN. BASED ON THIS...WILL REMOVE THE MENTION OF
THUNDER FROM THE FORECAST THROUGH MID-MORNING. DEWPOINTS HAVE
SURGED BACK INTO THE UPPER 60S AND LOWER 70S OVER MUCH OF THE
CWA...AND COMBINED WITH INCREASING MID/HIGH CLOUDS...FORECAST LOWS
MOSTLY IN THE UPPER 60S AND LOWER 70S APPEAR ON TRACK.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 240 PM TUESDAY...
MCS-INDUCED VORT MAX WILL MOVE ACROSS THE AREA ON WEDNESDAY...WITH
CONTINUED MOISTURE RETURN IN STRENGTHENING SOUTHWEST FLOW AHEAD OF
THE MID LEVEL SYSTEM. INSTABILITY WILL BE MARGINAL WITH WEAK
SHEAR...SBCAPE ~500J AND MID LEVEL LAPSE RATES ~5C/KM...BUT THE
VIGOROUS MID LEVEL VORT WILL BE SUPPORTED BY SOME UPPER DIFFLUENCE
WITH A 55-60KT UPPER JET EXITING THE AREA. POP WISE...WILL INTRODUCE
POPS IN THE WEST TOMORROW MORNING...WITH CONVECTION BECOMING LIKELY
ACROSS CENTRAL NC WITH THE TRANSLATION OF THE MID LEVEL SYSTEM AND
DIURNAL INSTABILITY CYCLE. HIGHS WILL BE HAMPERED BY CLOUDINESS...
ESPECIALLY IN THE WEST...WITH LOWER 80S WEST TO SOME UPPER 80S IN
THE EAST WHERE PRECIP WILL BE SLOWER TO ARRIVE.
WE REMAIN IN THE A FAVORABLE MOISTURE ADVECTION REGIME WITH DEEP
SOUTHWEST FLOW TOMORROW NIGHT WITH CYCLONIC FLOW ALOFT. POP CHANCES
WILL REMAIN IN THE HIGH CHANCE TO LIKELY RANGE WITH ONLY SMALL
CHANCES FOR THUNDER GIVEN A LULL IN MID LEVEL DISTURBANCES. MINS
WILL BE MILD GIVEN THE SOUTHERLY FLOW AND CLOUDINESS...68-72.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 250 PM TUESDAY...
OVERALL THE LONG TERM PERIOD WILL CONTINUE TO FEATURE A MEAN TROUGH
ACROSS THE EASTERN CONUS WITH A SERIES OF SHORTWAVES/WEAK FRONTS
PROGRESSING THROUGH THE AREA. THIS SET-UP WILL KEEP THE SUMMER HEAT
AT BAY WHILE PROVIDING PERIODS OF INCREASED SHOWER AND THUNDERSTORM
ACTIVITY.
PRECIP ASSOCIATED WITH THE NEXT UPPER TROUGH/SURFACE FRONT SHOULD BE
ONGOING TO START THE DAY ON THURSDAY. ALTHOUGH THE ACTUAL FRONT WILL
LIKELY NOT MOVE THROUGH THE AREA UNTIL LATE IN THE DAY...THE
PREFRONTAL TROUGH...HEATING (ALTHOUGH EXTENSIVE CLOUD COVER SHOULD
KEEP TEMPS DOWN SOME) AND ANY WEAK DISTURBANCES ALOFT SHOULD PROVIDE
ENOUGH OF A TRIGGER FOR CONVECTION VIRTUALLY ANYWHERE IN THE
FORECAST AREA. THEN AS THE FRONT MOVES THROUGH LATER IN THE DAY AND
INTO THE EVENING HOURS...PRECIP SHOULD TRANSLATE FROM WEST TO EAST.
ALTHOUGH WIDESPREAD SEVERE STORMS ARE NOT EXPECTED...WITH INCREASING
SHEAR AND POCKETS OF HIGHER INSTABILITY (DIFFERENTIAL HEATING FROM
ANY BREAKS IN THE CLOUDS)...AN ISOLATED STRONG TO SEVERE STORM
CANNOT BE RULED OUT. PRECIP SHOULD END FROM WEST TO EAST THURSDAY
NIGHT INTO FRIDAY MORNING.
BY FRIDAY...THE FRONT SHOULD STALL/WASH OUT SOMEWHERE NEAR THE
REGION. OVERALL...THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH PUSHING
IT SOUTH/EAST OF THE FORECAST AREA WHICH WOULD RESULT IN MOSTLY DRY
CONDITIONS FOR CENTRAL NC...WHILE THE GFS HAS SLOWER WITH THE
EASTWARD PROGRESSION (ALTHOUGH THE 12Z RUN OF THE GFS HAS COME MORE
IN LINE WITH THE ECMWF). NEVERTHELESS...GIVEN THE TIME OF THE YEAR
AND THE SIMILARITY TO RECENT EVENTS...WILL MAINTAIN AT LEAST A
MENTION OF PRECIP FOR FRIDAY AND SATURDAY...ESPECIALLY ON FRIDAY AND
MOSTLY ACROSS THE EASTERN/SOUTHERN PORTIONS OF THE FORECAST AREA.
THIS PATTERN WE ARE IN WILL CONTINUE AS YET ANOTHER SYSTEM WILL
APPROACH THE AREA LATE IN THE WEEKEND/EARLY NEXT WEEK (ALTHOUGH
TIMING REMAINS IN QUESTION). LATEST INDICATIONS SHOW PRECIP RAMPING
BACK UP LATE SATURDAY INTO SUNDAY...WITH EARLY NEXT WEEK DRYING OUT
AS THE FRONT SHIFTS/STALLS SOMEWHERE SOUTH/EAST OF THE FORECAST AREA
(ALTHOUGH AS CAN BE EXPECTED THIS FAR OUT...THIS IS TIMING SUBJECT
CHANGE.
TEMPS WILL ULTIMATELY BE DEPENDENT ON THE EXACT TIMING/EXTENT OF ANY
PRECIP THAT OCCURS...BUT SHOULD LARGELY BE NEAR TO SLIGHTLY BELOW
NORMAL THROUGH THE PERIOD.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 200 AM WEDNESDAY...
24-HR TAF PERIOD:
VFR CONDITIONS ARE EXPECTED TO PREVAIL THIS MORNING GIVEN WIDESPREAD
CLOUD COVER AND A RELATIVELY LOW LIKELIHOOD OF SUB-VFR FOG OR
STRATUS DEVELOPMENT. LIGHT SHOWER ACTIVITY PROGRESSING EAST INTO THE
FOOTHILLS/PIEDMONT MAY RESULT IN PERIODIC LIGHT RAIN AT THE INT/GSO
TERMINALS THIS MORNING...THOUGH CEILINGS AND VISBYS ARE LIKELY TO
REMAIN VFR. ALTHOUGH SHOWER/THUNDERSTORM ACTIVITY IS EXPECTED TO BE
PRESENT THIS AFT/EVE AND TONIGHT...UNCERTAINTY IS GREATER THAN
NORMAL WITH REGARD TO THE LOCATION/TIMING/COVERAGE OF SUCH
ACTIVITY...AND AT THIS TIME WILL SIMPLY MENTION VCSH AT ALL
TERMINALS.
LOOKING AHEAD:
EXPECT AN INCREASING POTENTIAL FOR SUB-VFR CEILINGS BY SUNRISE THU
MORNING...ALONG WITH A CONTINUED CHANCE FOR SHOWERS AND
THUNDERSTORMS THU INTO THU NIGHT AT ALL TERMINALS AS A WEAK COLD
FRONT APPROACHES FROM THE W/NW. RELATIVELY DRIER AND VFR CONDITIONS
ARE EXPECTED FRI AS THE FRONT STALLS IN THE EASTERN CAROLINAS...
THOUGH CHANCES FOR PRIMARILY AFT/EVE SHOWERS AND STORMS WILL
INCREASE OVER THE WEEKEND AS YET ANOTHER FRONT APPROACHES THE REGION
FROM THE NORTH. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...BLS
SHORT TERM...MLM
LONG TERM...KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
347 AM CDT WED JUL 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT WED JUL 31 2013
MAIN FORECAST CONCERN WILL BE SHOWER AND THUNDERSTORM COVERAGE IN
THE NEAR TERM. LATEST RADAR AT 0818 UTC SHOWS THAT THE SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY GRADUALLY SHIFTING TO THE SOUTH
AND EAST. THUNDERSTORMS ARE EXPECTED TO REMAIN SUB-SEVERE...PER THE
08 UTC SPC MESOANALYSIS...AS ML AND MU CAPE ARE MINIMAL EVEN
THOUGH 50 KTS OF 0-6 KM SHEAR IS PRESENT. THE 06 UTC HRRR AND 07
UTC RAP BOTH CONTINUE THE TREND OF MOVING SHOWER AND THUNDERSTORM
ACTIVITY TO THE SOUTH AND EAST...WITH ALL ACTIVITY COMING TO AN
END ACROSS THE SOUTH CENTRAL BETWEEN 13 TO 15 UTC.
FOR TODAY AND TONIGHT...NORTHWEST FLOW WILL PREVAIL
ALLOWING FOR DRY AND QUIET WEATHER TO TAKE HOLD AS HIGH PRESSURE
MOVES OVER THE REGION. COOLER THAN TEMPERATURES ARE EXPECTED WITH
HIGHS GENERALLY IN THE 70S AND LOWS IN THE UPPER 40S TO MID 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CDT WED JUL 31 2013
THE MEDIUM RANGE MODELS ARE STILL IN FAIRLY GOOD AGREEMENT WITH
PERSISTENT NORTHWESTERLY FLOW ALOFT OVER WESTERN AND CENTRAL NORTH
DAKOTA THROUGH THE PERIOD. THIS PATTERN WILL MAINTAIN BELOW NORMAL
TEMPERATURES ACROSS THE STATE THROUGH THE FIRST WEEK IN AUGUST.
NORTHWEST FLOW IS ALSO NOTORIOUS FOR LOW PREDICTABILITY WAVES
YIELDING THE POTENTIAL FOR ISOLATED CONVECTION NEARLY EVERY DAY.
HOWEVER...THE BEST CHANCES FOR WIDESPREAD PRECIPITATION LOOK TO BE
SATURDAY THROUGH SUNDAY AS THE PACIFIC NORTHWEST UPPER LOW
PROPAGATES ALONG THE CREST OF THE RIDGE INTO THE NORTHERN PLAINS.
THUNDERSTORMS SHOULD REMAIN BELOW SEVERE LIMITS GIVEN THE WEAK
INSTABILITY PROGGED DURING THE WEEKEND. HOWEVER...WILL CONTINUE TO
MONITOR TRENDS AND ADJUST THE FORECAST AS NEEDED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 112 AM CDT WED JUL 31 2013
AT 1 AM CDT...SHOWER AND THUNDERSTORM COVERAGE HAS INCREASED
SOUTH OF INTERSTATE 94 AS A WEAK COLD FRONTAL BOUNDARY CONTINUES
TO SLIDE SOUTH. HAVE INTRODUCED VCTS AT KDIK AND KBIS THROUGH 08Z.
ACTIVITY SHOULD DIMINISH OVER THE NEXT FEW HOURS...WITH VFR
CONDITIONS PREVAILING AT ALL SITES...EXCEPT FOR MVFR CONDITIONS IN
THUNDERSTORMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LTH
LONG TERM...TM
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
338 AM EDT WED JUL 31 2013
.SYNOPSIS...
A COLD FRONT ACROSS THE NORTHERN PLAINS WILL CONTINUE SOUTHEAST
TODAY AND DROP ACROSS THE AREA EARLY THURSDAY. WEAK HIGH PRESSURE
WILL BUILD IN ON FRIDAY AHEAD OF ANOTHER COLD FRONT THAT IS
EXPECTED ON SATURDAY. CANADIAN HIGH PRESSURE WILL BUILD IN SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE...NOW EAST OF THE AREA WILL CONTINUE TO LOOSE ITS
GRIP ON THE AREA TODAY AS A SURFACE LOW OVER SOUTHERN ILLINOIS
MOVES THROUGH KENTUCKY BEFORE EXPANDING OVER OHIO. ALSO A COLD
FRONT OVER THE NORTHERN PLAINS WILL CONTINUE TO DROP SOUTHEAST
TOWARD THE AREA. FOLLOWING THE NAM80...THE MODEL SHOWS A SHORT WAVE
MOVING INTO THE AREA FROM THE WEST DURING THE MORNING AND
AFFECTING THE EAST HALF OF THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE ACROSS THE AREA THROUGH THE DAY AND THE HRRR SHOWS PRECIP
BREAKING OUT IN THE WEST EARLY WHICH AGREES WITH THE CURRENT RADAR.
NOT EXPECTING AN ALL DAY RAIN BUT WILL HAVE CHANCE POPS INCREASING
TO LIKELY IN THE WEST TODAY WITH POPS INCREASING TO HIGH CHANCE
EAST. WILL HAVE HIGH A DEGREE OR TWO BELOW GUIDANCE GIVEN EXPECTED
CLOUDS AND PRECIP.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT LOOKING FOR PRECIP TO EXPAND ACROSS THE AREA AS COLD FRONT
APPROACHES FROM THE NORTHWEST AND MORE JET ENERGY DROP ACROSS THE
AREA. WILL HAVE CATEGORICAL POPS EAST AND LIKELY POPS WEST. WEAK
HIGH PRESSURE BUILDS IN FRIDAY SO WILL TAPER POPS WEST THROUGH THE
NIGHT INTO THURSDAY. WILL ALSO TAPER EAST BUT WILL HOLD ONTO A LOW
CHANCE POP TO COVER ANY LINGERING MOISTURE WITH THE AFTERNOON
INSTABILITY THAT DEVELOPS UNDER THE UPPER TROF. A BIT CONCERNED
ABOUT WESTERN COUNTIES FOR THE SAME REASON BUT FOR NOW WILL KEEP
DRY. FRIDAY AFTERNOON WILL BRING BACK CHANCE POPS AS SECOND COLD
FRONT APPROACHES FROM THE NORTHWEST. BOTH THE NAM AND GFS SHOW
SHORT WAVES DROPPING ACROSS THE AREA WITH THE MEAN TROUGH
REMAINING ACROSS THE GREAT LAKES AND OHIO VALLEY. CHANCE POPS WILL
CONTINUE FRIDAY NIGHT AND SATURDAY AS THE FRONT DROPS THROUGH. DRY
AIR AND BUILDING HIGH PRESSURE EXPECTED SATURDAY NIGHT. HIGHS
RATHER UNREMARKABLE FOR THIS TIME OF YEAR WITH MOST LOCATIONS ON
MOST DAYS LIKELY NOT GETTING OUT OF THE 70S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
NOT MUCH CHANGE GOING INTO NEXT WEEK. STILL MAINTAIN AN EASTERN U.S.
TROUGH AND THEREFORE TEMPERATURES THAT WILL BE RUNNING SLIGHTLY
BELOW NORMAL. THE UPPER TROUGH AXIS WILL BE EAST OF THE AREA SUNDAY
WITH SURFACE HIGH PRESSURE BUILDING IN ACROSS THE GREAT LAKES AND
OHIO VALLEY. NEXT MINOR UPPER WAVE RE-ENFORCING THE LONGWAVE
TROUGH...MAY BRING IN A FEW SHOWERS MONDAY NIGHT...GIVE OR TAKE A
LITTLE DUE TO TIMING IT THIS FAR OUT.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
SLOW MOVING AND WEAK SYSTEM TO CROSS THE AREA BETWEEN 12Z WED AND
12Z THU. FOR THE REST OF THE OVERNIGHT HOURS...VFR. ANY LIGHT SHRA
DURING THE DAYLIGHT HOURS TODAY WILL BE SPOTTY AND HIT OR MISS.
CEILINGS WILL EVER SO SLOWLY LOWER...STAYING VFR THROUGH THE
AFTERNOON. THE BEST CHANCES OF SHRA AND POSSIBLY A RUMBLE OF THUNDER
ARRIVE THIS EVENING...ALONG WITH THE CHANCES OF NON-VFR WEATHER. THE
BEST DEFINED SURFACE FEATURE...A WEAK COLD FRONT WILL BE NEARING
TOL/FDY BY 06Z THU. MAY HAVE SOME NON-VFR CEILINGS BEHIND THIS
FRONT. WINDS WILL BE LIGHT/VARIABLE TO LIGHT SOUTH TODAY AND INTO
TONIGHT.
.OUTLOOK...AREAS OF NON-VFR POSSIBLE WEDNESDAY NIGHT AND THURSDAY.
&&
.MARINE...
IT WILL REMAIN RELATIVELY QUIET ON THE LAKE FOR THE NEXT FEW DAYS.
ONLY FEATURES OF NOTE ARE A WEAK COLD FRONT CROSSING THE LAKE
TONIGHT. THIS AFTERNOON WINDS WILL BE LIGHT/VARIABLE...BECOMING
LIGHT SOUTH AHEAD OF THE FRONT. A SHIFT TO THE WEST CAN BE EXPECTED
AFTER THE FRONT...BUT SPEEDS STILL LIGHT. A SECONDARY TROUGH CROSSES
THE LAKE THURSDAY NIGHT AND HIGH PRESSURE THEN BUILDS ACROSS THE
OHIO VALLEY FOR FRIDAY. ANOTHER WEAK COLD FRONT SLIPS ACROSS THE
LAKE SATURDAY. UNCERTAIN AS TO IF CONDITIONS WILL GET CHOPPY ENOUGH
FOR ANY SMALL CRAFT ADV CONDITIONS. GRADIENT SEEMS FAIRLY WEAK. THE
CHOPPIER CONDITIONS MAY ACTUALLY ARRIVE BRIEFLY SUNDAY AS THE HIGH
BUILDS IN. OBVIOUSLY THERE IS LOW CONFIDENCE YET.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
1156 PM CDT TUE JUL 30 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
A FEW SHOWERS OR AN ISOLATED THUNDERSTORM WILL REMAIN POSSIBLE
OVERNIGHT AS A WEAK FRONTAL BOUNDARY REMAINS OVER THE AREA...PROBABILITY
REMAINS TOO LOW TO INCLUDE IN TAFS AT THIS TIME. MOIST AIRMASS
WILL LEAD TO MVFR VSBYS IN MANY LOCATIONS IN NE OK AND NW AR...
WITH WIDESPREAD MVFR CEILINGS LIKELY DEVELOPING IN THESE AREAS BY
12Z. CEILINGS LIFT BY AFTERNOON WITH VFR CONDITIONS THEREAFTER.
ISOLATED THUNDERSTORMS POSSIBLE IN TERRAIN OF W AR AND SE OK WED
AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 959 PM CDT TUE JUL 30 2013/
DISCUSSION...
MOST OF THE AFTERNOON ACTIVITY HAS DISSIPATED WITH THE LOSS OF
DAYTIME HEATING. HOWEVER...ACTIVITY PERSISTS OVER PORTIONS OF
NORTHWEST ARKANSAS...QUITE SIMILAR TO WHAT THE HRRR MODEL WAS
SUGGESTING THIS AFTERNOON. WITH THE WEAK BOUNDARY STALLED OVER THE
REGION IT IS HARD TO RULE OUT OVERNIGHT ACTIVITY. WILL LEAVE THE
SLIGHT CHANCE POPS IN FOR THE OVERNIGHT. THE 00Z NAM STILL
SUPPORTS THE DEVELOPMENT OF FOG ACROSS NORTHEAST OKLAHOMA AND
NORTHWEST ARKANSAS LATE TONIGHT. OVERALL...WILL NOT MAKE MUCH
CHANGE TO THE GOING FORECAST.
LACY
PREV DISCUSSION... /ISSUED 625 PM CDT TUE JUL 30 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
A FEW SHOWERS OR THUNDERSTORMS WILL LINGER THROUGH 03Z AS WEAK
FRONTAL BOUNDARY PUSHES THROUGH THE AREA OVERNIGHT. MINIMAL
IMPACT AT ANY FORECAST SITE EXPECTED AT THIS TIME. RAINFALL FROM
LAST NIGHT WILL LIKELY LEAD TO MVFR VSBYS AND CEILINGS ACROSS NE
OK AND NW ARKANSAS FROM ABOUT 08-15Z...ESPECIALLY IF SUFFICIENT
CLEARING TAKES PLACE. FRONT SHOULD BE MOSTLY SE OF AREA WED
AFTERNOON.
PREV DISCUSSION... /ISSUED 344 PM CDT TUE JUL 30 2013/
DISCUSSION...
WEAK FRONTAL BOUNDARY CURRENTLY FROM WEST CENTRAL MISSOURI
ON TO CENTRAL OKLAHOMA TO NORTH TEXAS WILL SLIDE SOUTHEAST
TONIGHT TO NEAR INTERSTATE 40 BY WEDNESDAY MORNING. FRONT
CONTINUES SLIDING SOUTH WEDNESDAY TO SOUTH OF RED RIVER.
ALTHOUGH PLENTY OF MOISTURE IS AVAILABLE..UPPER SUPPORT IS
LACKING WHICH TRANSLATES TO CHANCE POPS TONIGHT...MAINLY
BEFORE MIDNIGHT.
UPPER HIGH ANCHORED / CENTERED OVER NEW MEXICO-WEST TEXAS
BRINGS DRY NORTHWEST FLOW WEDNESDAY-THURSDAY. MINOR WAVES
IN THE NORTHWEST FLOW GENERATES LOW CHANCE POPS FRIDAY AND
THE WEEKEND...MAINLY NORTHEAST AREAS.
LOW CHANCE POPS PREVAIL EARLY NEXT WEEK WITH NEAR SEASONAL
(HOT) WEATHER. UNUSUAL...FOR SUMMER...PATTERN FORECAST BY
BOTH ECMWF/GFS NEXT WEEK. SIGNIFICANT HUDSON BAY UPPER LOW
DIVES INTO NORTH CENTRAL STATES...WHILE UPPER RIDGE BUILDS
NORTH INTO BRITISH COLUMBIA YUKON & NORTHWEST TERRITORIES.
GW
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1103 PM CDT TUE JUL 30 2013
.UPDATE...
ISSUED AT 1000 PM CDT TUE JUL 30 2013
MAINLY DRY RIGHT NOW ACROSS THE CWA...WITH JUST MAYBE SOME SPRINKLES
NORTH OF INTERSTATE 90. CONVECTION EVOLUTION OVERNIGHT REMAINS LOW
CONFIDENCE. HOWEVER IT APPEARS LIKE WE WILL SEE A LULL OVER THE NEXT
FEW HOURS. LATER TONIGHT...SEE PRETTY STRONG THETAE ADVECTION AROUND
800 TO 850 MB...FOCUSED ACROSS THE SOUTHWEST HALF OF THE CWA.
MEANWHILE...BEST UPPER LEVEL FORCING WILL MOVE TO OUR NORTH. LATEST
NAM AND HRRR IN PRETTY GOOD AGREEMENT THAT STORMS CURRENTLY OVER
NORTHERN WYOMING AND SOUTHERN MONTANA WILL MAINTAIN THEMSELVES AS
THEY PUSH EAST TOWARDS OUR AREA. MOST MODEL SOLUTIONS HINT AT AREAS
ALONG AND SOUTH OF INTERSTATE 90 BEING FAVORED BY THIS LATE NIGHT
CONVECTION. THIS WOULD MAKE SENSE GIVEN WHERE THETAE ADVECTION SEEMS
TO WANT TO FOCUS. HOWEVER WITH THE WAVE PASSING TO OUR NORTH...AND
THE RAP AND HRRR BOTH SHOWING ACTIVITY NORTH OF INTERSTATE 90...WILL
JUST KEEP AN EQUAL THREAT OF 40 TO 50 POPS ACROSS THE ENTIRE
CWA...WITH PROGRESSION FROM WEST TO EAST FROM ABOUT 09Z TO 15Z. GIVEN
THE ELEVATED NATURE OF CONVECTION AND LOW INSTABILITY...NOT THINKING
WE SEE ANY SEVERE WEATHER WITH THIS ACTIVITY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 303 PM CDT TUE JUL 30 2013
UPPER DYNAMICS AND RESULTING LIFT SHOULD BE BEST FOR STORMS IN THE
NORTHERN PART OF OUR FORECAST AREA TONIGHT...BUT SOME SIGNIFICANT
CELLS POSSIBLE SOUTHWEST ALSO WHERE BETTER HEATING AND INSTABILITY
WILL COMBINE WITH DECENT MOISTURE. WIND FIELDS ARE NOTHING TO BRAG
ABOUT AT ANY LEVEL AND WILL KEEP TOP POPS NORTH BARELY INTO THE
LIKELY RANGE. WILL BRING THE THREAT INTO THE FAR WEST AT THE START
OF THE EVENING AND MOVE IT SLOWLY EAST. SPC MENTION OF CELLS AND
CLUSTERS SEEMS RIGHT AS IT DOES NOT LOOK LIKE AN MCS ENVIRONMENT.
SEVERE RISK SLIGHT FOR EARLY THIS EVENING OUT WEST ALSO SEEMS RIGHT.
THE SLOW MOVEMENT OF THE THREAT WILL BRING IT INTO THE EXTREME
SOUTHEAST PART OF OUR AREA...SUCH AS TO SLB IN NORTHWEST IA...ABOUT
7 AM CDT/12Z WEDNESDAY. BY THAT TIME THE THREAT WILL BEGIN TO
DECREASE FROM THE NORTHWEST. EXCEPT FOR THE 12Z NAM RUN WHICH
SUGGESTS HANGING ONTO THE THREAT SOUTHEAST WEDNESDAY EVENING...
MODELS HAVE ACTIVITY OUT OF THE DAY BY THE END OF THE WEDNESDAY
DAYTIME PERIOD. SKIES SHOULD GO MOSTLY CLEAR FROM THE NORTHWEST
WEDNESDAY BEHIND THE DECREASE IN SHOWERS AND STORMS.
ASIDE FROM THE SHOWERS AND STORMS...SOLID LOW CLOUDS MAY STAY
ANCHORED SOUTHEAST/FAR EAST INTO MUCH OF TONIGHT...THOUGH THERE ARE
A FEW HOURS OF DAYTIME HEATING LEFT TO BREAK THE CLOUDS UP A LITTLE
MORE. LOW TEMPERATURE SHOULD BE MOSTLY IN THE LOWER 60S TONIGHT.
UPPER 70S NORTHEAST TO LOWER 80S SOUTHWEST LOOK GOOD FOR HIGHS
WEDNESDAY BASED ON LINGERING CLOUD COVER WITH THE CONTINUING MORNING
PRECIPITATION.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 303 PM CDT TUE JUL 30 2013
NOT MUCH ACTIVITY WEDNESDAY NIGHT AS CONVECTIVE THREAT SHIFTS SOUTH
AND EAST AND HIGH PRESSURE BUILDS IN. WITH CLEAR SKIES AND LIGHT
WINDS WILL GO A LITTLE COOLER THAN GUIDANCE...AIMING FOR THE MID TO
UPPER 50S IN MOST SPOTS. NOT OUT OF THE QUESTION FOR A FEW LOW SPOTS
TO TOUCH 50 DEGREES.
A FAIRLY STRONG LITTLE JET MAX SCOOTS THROUGH MINNESOTA ON THURSDAY
AND THURSDAY NIGHT WHICH WILL DRIVE A BOUNDARY SOUTH THURSDAY NIGHT.
TO THE SOUTH AND SOUTHWEST OF THIS JET MAX THE LOW AND MID LEVEL
WIND FIELD ENHANCES WITH A MODERATELY STRONG LOW LEVEL JET AROUND
850MB FOCUSING AROUND THE MISSOURI RIVER FROM ABOUT 0Z FRIDAY
THROUGH 6Z FRIDAY. DEEPER LAYER SHEAR INCREASES A BIT DURING THIS
TIME AS WELL AS THE 700-500MB WINDS TURN MORE NORTHWEST AND
STRENGTHEN A BIT. A SOMEWHAT STABLE AIR MASS WILL LIKELY BE IN PLACE
INITIALLY BUT WITH THE INCREASING LOW LEVEL JET BETTER ELEVATED
INSTABILITY LIKELY TO FEED INTO THE FAR SOUTHERN CWA FROM 0Z TO 6Z
FRIDAY. WHILE THE SEVERE THREAT WILL BE HIGHER TO THE SOUTH AND
SOUTHWEST OF THE CWA THERE WILL STILL BE A THREAT IN THE FAR
SOUTHERN CWA. GOING FORECAST FOR THIS LOOKS PRETTY GOOD AND WILL NOT
STRAY TOO FAR FROM IT. THE FAR NORTHERN CWA MAY HAVE TROUBLE GETTING
ANY ACTIVITY THURSDAY AND THURSDAY NIGHT.
FRIDAY WILL SEE MORE STABLE AIR SETTLE IN FROM THE NORTH AND SHOULD
PROVIDE THE AREA WITH A QUIET AND FAIRLY PLEASANT DAY. HIGHS MAINLY
MID 70S TO LOWER 80S WITH FAIRLY AVERAGE SUMMER TIME HUMIDITY
VALUES.
FOR SATURDAY THROUGH TUESDAY...OVERALL PATTERN CONTINUES TO BE
SOMEWHAT ANOMALOUS FOR THIS TIME OF YEAR WITH A WEAK RIDGE OF HIGH
PRESSURE OVER THE WESTERN HIGH PLAINS AND MODERATE WEST TO NORTHWEST
FLOW ALOFT. THIS KEEPS THE LOWER AND MID LEVEL TEMPERATURES A LITTLE
COOLER THAN NORMAL AS WELL SO SUSPECT THAT TEMPERATURES WILL REMAIN
BELOW NORMAL THROUGH THE PERIOD. IN FACT LOOKING AT THE ECMWF
ENSEMBLE OUTPUT OF 850MB TEMPERATURES THERE IS A REALLY STRONG
SIGNAL TO REMAIN BELOW NORMAL AS 90 TO 95 PERCENT OF THE MEMBERS ARE
COOLER THAN THE THE SEASONAL NORMAL THROUGH ABOUT AUGUST 12. IT DOES
APPEAR THAT THIS PATTERN WILL BE A BIT MORE SUPPORTIVE OF RAIN
CHANCES SO WILL NEED TO INCLUDE SOME MENTION DURING THIS TIME. WILL
AIM FOR THE BEST CHANCE FOR THIS SUNDAY INTO MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1103 PM CDT TUE JUL 30 2013
QUIEST START TO THE PERIOD...WITH SCATTERED SHRA/TSRA EXPECTED TO
MOVE BACK INTO WESTERN AREAS AFTER 08Z-09Z. THIS ACTIVITY WILL MOVE
ACROSS THE FORECAST AREA THROUGH THE MORNING...FOLLOWED BY GRADUAL
CLEARING THROUGH THE AFTERNOON. WITH RELATIVELY WEAK INSTABILITY
THROUGH THE EARLY MORNING...ALONG WITH LOW CONFIDENCE IN TIMING AND
COVERAGE...HAVE LEFT MENTION OF THUNDER OUT OF KHON/KFSD TAFS...BUT
DO HAVE TEMPO GROUP FOR SHRA FOR MOST LIKELY TIME. ASIDE FROM THE
CONVECTIVE POTENTIAL...VFR CONDITIONS WILL BE DOMINANT. HOWEVER MVFR
TO LOCALLY IFR VISIBILITIES COULD EXPAND BACK INTO PARTS OF NORTHWEST
IOWA DURING THE EARLY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHENARD
SHORT TERM...
LONG TERM...08
AVIATION...JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 PM CDT TUE JUL 30 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 215 PM CDT TUE JUL 30 2013
CURRENTLY AS OF 19Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED SUBTROPICAL
RIDGING OVER THE SOUTHWESTERN U.S....TROUGHING OVER SASKATCHEWAN AND
MANITOBA...AND WEST-NORTHWEST FLOW FROM MONTANA INTO THE FORECAST
AREA. WITHIN THE FLOW...A FEW SHORTWAVES WERE CROSSING NORTH DAKOTA.
CONDITIONS ARE DRY ACROSS THE FORECAST AREA...BUT PLENTY OF STRATUS
OF THE LOW TO MID LEVEL VARIETY EXISTS. THESE CLOUDS HAVE HELD
TEMPERATURES DOWN SOMEWHAT...BUT ENOUGH SUN HAS MADE IT THROUGH WITH
THE 850MB TEMPS BETWEEN 11-13C PER 12Z RAOBS TO BRING READINGS INTO
THE 70S. TO THE WEST...A COLD FRONT WAS PRESENT OVER FAR WESTERN
MN...JUST AHEAD OF THE SHORTWAVES. THE COLD FRONT SO FAR HAS NOT
DONE ANYTHING PRECIPITATION WISE...BUT THERE HAS BEEN CONVECTION
BEHIND THE FRONT OVER SOUTHERN SOUTH DAKOTA.
SYNOPTIC OVERVIEW...
MODELS ARE IN VERY GOOD AGREEMENT DROPPING A PORTION OF THE
TROUGHING OVER SOUTH CENTRAL CANADA THROUGH THE FORECAST AREA
WEDNESDAY AFTERNOON. THIS PORTION OF THE TROUGH...OR SHORTWAVE...IS
OF MOST CONCERN...SINCE IT WILL PUSH THE COLD FRONT TO OUR WEST
ACROSS THE FORECAST AREA. IT APPEARS THE SHORTWAVES CURRENTLY ACROSS
NORTH DAKOTA WILL HEAD EAST TOWARDS UPPER MI.
HAZARDS...
SOME SEVERE WEATHER POTENTIAL WEDNESDAY AFTERNOON GIVEN 0-6 KM SHEAR
VALUES AROUND 40 KT PRESENT WITH A FRONTAL PASSAGE. HOWEVER...THERE
ARE SERIOUS CONCERNS ON AVAILABLE INSTABILITY AS DESCRIBED IN THE
DETAILS BELOW. SHOULD SEVERE WEATHER OCCUR...HAIL WILL BE THE MAIN
CONCERN.
DETAILS...
A LIGHT SOUTHERLY FLOW AHEAD OF THE WESTERN MN COLD FRONT WILL ALLOW
SOME OF THE LOWER CEILING STRATUS AND FOG THAT HAS PRESENT JUST
SOUTH OF THE FORECAST AREA TO COME UP INTO NORTHEAST IOWA AND FAR
SOUTHWEST WISCONSIN TONIGHT. HAVE ADDED SOME FOG MENTION TO THESE
LOCATIONS. OTHERWISE...TONIGHT LOOKS FAIRLY QUIET WITH BASICALLY NO
ISENTROPIC LIFT AND ALL SHORTWAVE FORCING HEADING UP TO THE NORTH.
ONE ITEM OF INTEREST PRESENT IN SOME PAST HRRR RUNS AS WELL AS THE
30.12Z ECMWF AND HIRES-ARW IS A BAND OF SHOWERS FROM NEAR WABASHA
COUNTY TO TAYLOR COUNTY BETWEEN 00-09Z. GIVEN THE 30.17Z HRRR RUN IS
DRY AND AFOREMENTIONED FORCING SIGNALS ARE WEAK TO NONE...HAVE KEPT
THE FORECAST DRY IN THIS AREA. A MIX OF LOW AND HIGHER STRATUS
SHOULD PERSIST THROUGH MUCH OF THE NIGHT...HELPING TO KEEP
TEMPERATURES UP.
ON WEDNESDAY...THE NEXT SHORTWAVE OF FOCUS DROPPING OUT OF SOUTH
CENTRAL CANADA WILL PROVIDE A PERIOD OF DPVA ACROSS THE FORECAST
AREA...ALONG WITH GIVING THE COLD FRONT OVER FAR WESTERN MN A BIGGER
PUSH. THE BIG QUESTIONS ARE BOTH FRONTAL TIMING AND HOW WARM CAN WE
GET PRIOR TO FRONTAL ARRIVAL. ALTHOUGH THERE IS NOW LESS CONCERN
FOR LOW CEILING STRATUS OVER ABOUT THE NORTHWEST 2/3 OF THE FORECAST
AREA...ISENTROPIC LIFT FIELDS SUGGEST A GOOD AMOUNT OF MID/HIGH
CLOUDS WILL OVERSPREAD THE AREA AHEAD OF THE SHORTWAVE AND COLD
FRONT. THE 30.12Z NAM EVEN DEVELOPS SOME LIGHT PRECIPITATION OUT OF
THESE CLOUDS NORTH OF I-90. MAIN COLD FRONTAL TIMING STILL LOOKS TO
BE DURING THE AFTERNOON WHICH IS GOOD...BUT THE AFOREMENTIONED
CLOUDS MAY LIMIT HEATING AND THUS BOTH CAPE AND CONVECTIVE
DEVELOPMENT ON THE FRONT. MODEL CONSENSUS IS TO GET HIGH
TEMPERATURES PRIOR TO FRONTAL ARRIVAL UP INTO THE MID 70S TO AROUND
80...WHICH RESULTS IN ABOUT 500-1000 J/KG OF TALL...THIN CAPE. THE
SKINNY NATURE OF THE CAPE WILL HELP MINIMIZE THE SEVERE WEATHER
POTENTIAL DESPITE FAVORABLE SHEAR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 215 PM CDT TUE JUL 30 2013
SYNOPTIC OVERVIEW...
30.12Z ECMWF/GFS/CANADIAN ALL SUGGEST A REX BLOCK STAYING MOSTLY IN
PLACE OVER WESTERN CANADA INTO THE GULF OF ALASKA...ALONG WITH
TROUGHING OVER SOUTHEAST CANADA INTO THE GREAT LAKES
REGION...THROUGH THE LONG TERM PERIOD. THIS MEANS THE FORECAST AREA
WILL STAY IN COOL...NORTHWEST FLOW WITH SHORTWAVES COMING THROUGH
THAT CAN BE HARD TO TIME. WHETHER OR NOT THESE SHORTWAVES PRODUCE
PRECIPITATION WILL DEPEND ON MOISTURE AVAILABILITY.
WEDNESDAY NIGHT THROUGH FRIDAY...
IN THE WAKE OF WEDNESDAYS COLD FRONTAL PASSAGE...THE 30.12Z NAM
BRINGS SOME PRECIP THROUGH THE SOUTHWESTERN HALF OF THE FORECAST
AREA WEDNESDAY NIGHT. THIS IS A RESULT OF SOME WEAK 305K ISENTROPIC
LIFT AHEAD OF A WEAK SHORTWAVE TRAVERSING IOWA...AS WELL AS BEING IN
THE LEFT EXIT REGION OF A 100 KT JET STREAK. ALL OTHER AVAILABLE
GUIDANCE IS DRY...CONSISTENT TOO WITH THE PREVIOUS FORECAST.
THEREFORE...HAVE KEPT A DRY FORECAST GOING. MODELS HAVE TRENDED
DRIER ON THURSDAY WITH ANY CONVECTIVE FORCING WELL OFF TO OUR NORTH
OR SOUTHWEST. ADDITIONALLY...IT APPEARS THERE SHOULD BE A SURGE OF
DRY AIR ON THURSDAY TO HELP MIX DEWPOINTS DOWN...ALSO FAVORING A
DRIER FORECAST. THURSDAY NIGHT INTO FRIDAY MAY STAND TO HAVE THE
BEST CHANCE FOR PRECIPITATION IN THIS NORTHWEST FLOW...IF YOU
BELIEVE THE NAM. MODELS ARE IN GOOD AGREEMENT DROPPING A SHORTWAVE
THROUGH NORTHERN WI FRIDAY MORNING. THE NAM IS MOST ROBUST IN
GENERATING BOTH LIFT AND QPF FROM THIS SHORTWAVE. HOWEVER...THE
GFS/ECMWF/CANADIAN ARE ALL MUCH DRIER AND SOME EVEN SUGGEST A DRY
FORECAST. THEREFORE...CONFIDENCE IN THE NAM SCENARIO IS QUITE LOW.
DID MAINTAIN A 20 PERCENT CHANCE FOR LATE THURSDAY NIGHT ACROSS THE
FORECAST AREA...AS WELL AS SOUTH OF I-90 ON FRIDAY...IN THE EVENT
THE NAM IS RIGHT. WITH 850MB TEMP ANOMALIES HOVERING IN THAT 0.5-1
STANDARD DEVIATION BELOW NORMAL...TEMPERATURES SHOULD CONTINUE TO
RUN ABOUT 5F DEGREES BELOW NORMAL FOR HIGHS. GENERALLY FOLLOWED A
MODEL GUIDANCE CONSENSUS FOR BOTH HIGHS AND LOWS.
FRIDAY NIGHT THROUGH TUESDAY...
DESPITE A NORTHWEST FLOW DURING THE WEEKEND...CONFIDENCE OF HAVING
IT DRY IS INCREASING. THE REASON IS THAT MODELS HAVE BEEN
CONSISTENTLY SHOWING CANADIAN HIGH PRESSURE BUILDING INTO THE
FORECAST AREA IN THE WAKE OF THAT SHORTWAVE CROSSING NORTHERN WI
FRIDAY MORNING. GIVEN THE CANADIAN SOURCE REGION...THE WEEKEND DOES
LOOK COOL...BUT NOT NEARLY AS COLD AS LAST WEEKEND. 850MB TEMPS DROP
TO 10-12C ON SATURDAY AND 8-11C ON SUNDAY WHICH AT MOST ARE 1-1.5
STANDARD DEVIATIONS BELOW NORMAL. THESE TEMPS STILL SUPPORT HIGHS IN
THE 70S. THE BIGGER QUESTION WILL BE LOWS...WHICH HIGHLY DEPENDS ON
TIMING WHEN THE SURFACE HIGH BUILDS OVERHEAD FOR PRIME RADIATIONAL
COOLING CONDITIONS. LOWS IN THE TYPICAL COLDER SPOTS IN THE 40S ARE
CERTAINLY POSSIBLE.
HEADING INTO EARLY NEXT WEEK...THERE ARE SIGNS IN THE 30.12Z
ECMWF/GFS OF A MORE SIGNIFICANT SHORTWAVE DROPPING THROUGH THE
NORTHWEST FLOW...COMING THROUGH THE FORECAST AREA ON MONDAY. THIS IS
A BIT OF A CHANGE FOR THE ECMWF...BEGINNING TO LEAN MORE TOWARDS
WHAT THE PAST FEW GFS RUNS HAVE SUGGESTED. IN ANY EVENT...CHANCES OF
SHOWERS AND THUNDERSTORMS ARE REQUIRED FOR SUNDAY NIGHT AND MONDAY
TO ACCOUNT FOR THE SHORTWAVE AND ASSOCIATED FORCING. FOR MONDAY
NIGHT AND TUESDAY...CONTINUITY AND MODEL CONSENSUS SUGGESTS HOLDING
ONTO 20-30 PERCENT CHANCES DURING THIS TIME PERIOD. THESE CHANCES
ARE ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE. HOWEVER...NEW
30.12Z GUIDANCE...PARTICULARLY THE ECMWF...SUGGESTING THAT A DRIER
FORECAST MAY BE MORE CORRECT. GIVEN THE UNCERTAINTY BEING IN
NORTHWEST FLOW AND HOW FAR OUT TUESDAY IS IN THE FORECAST...HAVE
LEFT THE CHANCES ALONE FOR NOW. 850MB TEMPS REMAIN BELOW
NORMAL...BETWEEN 10-12C...KEEPING HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1146 PM CDT TUE JUL 30 2013
AN AREA OF CLEARING HAS DEVELOPED THIS EVENING ACROSS WESTERN AND
SOUTHERN MINNESOTA AND IS MAKING STEADY EASTWARD PROGRESS. LOOKS
LIKE IT SHOULD BE INTO KRST BY TAF ISSUANCE TIME AND THEN THE
QUESTION BECOMES WHETHER THIS WILL ALLOW FOG AND LOW CLOUDS TO
FORM OVERNIGHT WITH GOOD RADIATIONAL COOLING CONDITIONS. ALREADY
SEEING A FEW LOCATIONS WITH MVFR FOG WHERE IT HAS BEEN CLEAR FOR A
COUPLE OF HOURS...SO THE POTENTIAL IS THERE FOR THIS TO OCCUR.
THUS WILL LEAVE IN THE POSSIBILITY OF IFR CONDITIONS OVERNIGHT AT
KRST. NOT AS CLEAR CUT FOR KLSE WHETHER THE CLEARING WILL ARRIVE
IN TIME WITH ENOUGH HOURS OF COOLING LEFT IN THE NIGHT FOR THE FOG
TO DEVELOP. BUT BEFORE THAT CAN HAPPEN...A SMALL AREA OF MVFR
CLOUDS NEEDS TO MOVE THROUGH FIRST. WILL SHOW THESE COMING IN
AROUND 08Z AND WHILE IT MAY SCATTERED OUT FOR A WHILE...IT THEN
HAS THE POSSIBILITY OF FOGGING RIGHT BACK UP. WILL SHOW THE MVFR
CLOUDS HOLDING ON WITH THE POSSIBILITY OF IFR CONDITIONS AS WELL.
THE WIND SHIFT TO THE WEST AHEAD OF THE MAIN FRONT WILL OCCUR AT
BOTH SITES BETWEEN 12 AND 15Z TO END ANY MVFR/IFR CONDITIONS THAT
DEVELOP OVERNIGHT. THE 31.00Z NAM HAS COME IN WITH EVEN LESS
FORCING AND CONVERGENCE ALONG THE FRONT AND SHOWS VERY LITTLE RAIN
OCCURRING. BASED ON THIS HAVE DROPPED THE VCSH OUT OF THE FORECAST
AND WILL JUST SHOW SOME SCATTERED CUMULUS AS THE FRONT COMES
THROUGH WITH HIGH VFR CEILINGS THAT WILL THEN SCATTER OUT DURING
THE EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
804 AM EDT WED JUL 31 2013
.PREV DISCUSSION... /ISSUED 431 AM EDT WED JUL 31 2013/
SHORT TERM /TODAY THROUGH THURSDAY/...
RAIN ALREADY RETURNING TO THE AREA TODAY AS PERTURBATIONS MOVE
THROUGH THE UPPER LEVEL FLOW. MEDIUM RANGE AND HI RES MODELS ARE
IN AGREEMENT THAT THE CWA WILL SEE CONVECTION TODAY...HOWEVER
CONSIDERABLE DISAGREEMENT IN TERMS OF TIMING. WRF NMM SEEMS TO
HAVE A SURGE IN CONVECTION DURING THE MORNING THAN A LULL DURING
THE AFTERNOON. LOCAL WRF TENDS TO WEAKEN CONVECTION THIS
MORNING...DEVELOP ACROSS CENTRAL GEORGIA THIS AFTERNOON AND THEN
ACROSS THE NORTH DURING THE LATE AFTERNOON. HRRR CONTINUES TO
SHIFT THE CURRENT CONVECTION TO THE EAST AND THEN DEVELOP
CONVECTION ACROSS THE ENTIRE CWA AS THE AFTERNOON APPROACHES.
GIVEN ALL OF THIS AND MEDIUM RANGE MODELS...GOOD CONFIDENCE OF
HIGH POPS FOR TODAY...HOWEVER LOW CONFIDENCE IN TERMS OF TIMING.
FORECAST IS MOST CLOSELY IN LINE WITH THE HRRR.
FOR THE STORMS CURRENTLY ONGOING...MAIN CONCERN IS GUSTY WINDS. GFS
CAPE FORECAST LOOKS MORE REASONABLE TODAY...RATHER THAN LAST NIGHT
WHERE IT WAS GAPPING THE CWA WITH INSTABILITY. FORECAST CAPE VALUES
ARE AROUND 1500-2000 J/KG FOR THE AFTERNOON. STILL EXPECTING BETWEEN
20 AND 30KTS OF DEEP LAYER SHEAR TODAY AND BETWEEN THIS AND THE
INSTABILITY VALUES...COULD SEE ISOLATED SEVERE STORMS. MAIN THREAT
WILL BE DAMAGING WINDS. ALTHOUGH THE CWA HAS HAD A FEW DAYS WITHOUT
RAIN...ALLOWING US TO BE ABLE TO HANDLE MORE IN TERMS OF
RAINFALL...WILL STILL HAVE TO MONITOR RAINFALL AMOUNTS CLOSELY.
AROUND ONE TO ONE AND A HALF INCHES OF RAIN IS EXPECTED THROUGH
THURSDAY...WITH LOCALIZED HIGHER AMOUNTS POSSIBLE. 1HR FFG VALUES
ARE AROUND 2.5 TO 3.5 INCHES SO WE SHOULD BE ABLE TO HANDLE THESE
AMOUNTS...BUT THERE IS THE POTENTIAL FOR LOCALIZED FLOODING WITH
HIGHER RAINFALL VALUES.
SFC FRONT MOVES THROUGH CWA ON THURSDAY. CONVECTION SHOULD DECREASE
BY THURSDAY MORNING...BUT THEN INCREASE AGAIN ON THURSDAY ALONG AND
SOUTH OF THIS FRONT.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AT THE BEGINNING OF THE PERIOD A WEAK FRONTAL BOUNDARY WILL BE
MOVING INTO CENTRAL GEORGIA. CONVECTION ASSOCIATED WITH THIS
BOUNDARY MAY BE ONGOING. EXPECT THIS CONVECTION TO BE ON A GENERAL
WEAKENING TREND THROUGH THE EVENING. AT THIS POINT FRIDAY LOOKS TO
BE THE BEST DAY FOR NO POPS ACROSS THE REGION AS WE WAIT FOR
NORTHWEST FLOW TO BRING US ANOTHER IMPULSE AND RAIN TO THE AREA.
MOISTURE ASSOCIATED WITH DORIAN SHOULD HELP IN INCREASE PWATS AND
RAIN CHANCES THIS WEEKEND AND INTO NEXT WEEK. THE MODELS SUGGEST
THAT WE KEEP NORTHWEST FLOW THROUGH AT LEAST MID NEXT WEEK...WHEN
THEY TRY TO BUILD A RIDGE INTO THE SOUTHERN UNITED STATES. MAY
CONCERN IN THE EXTENDED COULD BE RAINFALL ASSOCIATED WITH THE
SHOWERS AND THUNDERSTORMS THIS WEEKEND AND INTO EARLY NEXT WEEK.
THIS WILL NEED TO BE MONITORED CLOSELY FOR POSSIBLE FLOODING AS WE
APPROACH THIS WEEKEND.
ARG
&&
.AVIATION...
12Z UPDATE...
MAIN CONCERN IS TIMING OF SHRA/TSRA THIS MORNING AND LIKELIHOOD OF
TSRA THIS AFTERNOON AND EARLY EVENING. NO SIGN THAT BANDS OF SHRA
WITH EMBEDDED TSRA OVER AL AND NW GA WILL DISSIPATE...HIGH
CONFIDENCE THAT PRECIP WILL CONTINUE THRU MUCH OF THE DAY.
INTENSITY OF TSRA WILL LIKELY BE HELD DOWN BY CLOUDS AND RAIN SO
HAVE KEPT VSBYS UP. WINDS WILL SHIFT TO SSW IN ATL AREA AIRPORTS
AROUND 17Z. WILL LIKELY SEE CIGS APPROACH IFR LATE TONIGHT AFTER
09Z.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF SHRA/TSRA. HIGH CONFIDENCE ON WIND
SHIFT.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 69 88 68 / 70 60 30 20
ATLANTA 84 71 87 70 / 80 60 30 10
BLAIRSVILLE 77 66 83 62 / 90 60 20 10
CARTERSVILLE 85 69 88 66 / 80 60 20 10
COLUMBUS 88 72 91 72 / 70 70 50 30
GAINESVILLE 82 70 86 68 / 70 60 30 10
MACON 87 71 90 70 / 90 50 50 30
ROME 84 70 89 66 / 90 70 20 10
PEACHTREE CITY 84 70 87 66 / 90 50 30 20
VIDALIA 88 73 88 72 / 70 80 60 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....ARG
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1009 AM CDT WED JUL 31 2013
.UPDATE...
ISSUED AT 959 AM CDT WED JUL 31 2013
SATELLITE TRENDS THIS MORNING SHOW THE CLOUDS ARE
THINNING/CLEARING. THIS THINNING/CLEARING WILL CONTINUE DURING THE
LATE MORNING AND EARLY AFTERNOON HOURS.
THERE ARE QUESTIONS REGARDING THE POTENTIAL FOR DIURNAL CONVECTION
THIS AFTERNOON. THERE IS NO REAL COHERENT BOUNDARY AND THE FORCING
IS QUITE WEAK. IMMEDIATE TRENDS FROM THE RAP SHOW DOWNWARD MOTION
CONTINUING INTO LATE MORNING BEFORE SOME LIFT DEVELOPS AHEAD OF
THE NEXT SHORTWAVE IN THE AFTERNOON. FCST SOUNDINGS SHOW
CONVECTIVE TEMPERATURES CLIMBING INTO THE UPPER 70S WHICH IS RIGHT
AROUND THE MAX TEMPERATURES FOR THE DAY.
SO...WILL CONTINUE THE POSSIBILITY OF ISOLATED
SHOWERS/THUNDERSTORMS ACROSS MAINLY THE NORTHERN CWFA DURING THE
AFTERNOON FOR NOW. THE POSSIBILITY DOES EXIST THAT THE PRECIP
POTENTIAL MAY GET PULLED DEPENDING UPON HOW THINGS EVOLVE DURING
THE AFTERNOON. ..08..
&&
.SYNOPSIS...
ISSUED AT 305 AM CDT WED JUL 31 2013
ANALYSIS AT 07Z (2 AM CDT) DEPICTS AREA UNDER LOW CLOUDS AND FOG AS
REMNANTS OF UPPER DISTURBANCE FROM YESTERDAY MOVES EAST. SURFACE
ANALYSIS PRESSURE RISE AND FALL PATTERN SUPPORTS UPPER AIR AND MOST
SOLUTIONS OF SLIGHTLY DRIER AIR AND SUBSIDENCE TO ARRIVE NEXT
SEVERAL HOURS FROM THE NORTHWEST. NW FLOW TO CONTINUE OVER AREA
NEXT SEVERAL DAYS KEEPING REGION NEAR TO SLIGHTLY BELOW NORMAL
REGARDING TEMPERATURES AS HAS BEEN THE CASE NOW FOR MUCH OF THIS
SUMMER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT WED JUL 31 2013
TODAY...ANALYSIS SUPPORTS LOW CLOUDS AND AREAS OF FOG WITH
VISIBILITIES OF 1-3 MILES TO BURN OFF BETWEEN 8-10 AM. SUBSIDENCE
WITH DIFFLUENT LOW LEVEL FLOW AND MIXING SUGGESTS CONVECTIVE
TEMPERATURES UNLIKELY TO BE REACHED AND THUS DRY CONDITIONS
WARRANTED. A WEAK UPPER DISTURBANCE IN SOUTH DAKOTA WILL NEED TO
BE MONITORED BY DAY SHIFT BUT NOWCAST TOOLS SUGGEST IT WILL BE
DRY. LOW LEVEL THERMAL FIELDS AND MODEST BL MIXING INDICATE HIGHS
WITHIN A DEGREE OR TWO OF 80 DEGREES FOR TODAY...A WARM MID SUMMER
DAY WITH DEWPOINTS IN THE LOWER TO MIDDLE 60S FOR MODERATE HUMIDITY.
THESE TEMPERATURES ARE GENERALLY 3 TO 5 DEGREES BELOW NORMAL.
TONIGHT...LIGHT NORTHWEST WINDS SHOULD BRING IN ENOUGH DRIER AIR
AND ENOUGH MIXING TO LIMIT ANY FOG FORMATION TONIGHT. MOSTLY FAIR
SKIES WILL ALLOW FOR MINS IN THE UPPER 50S FAR NW SECTIONS TO THE
LOWER 60S ELSEWHERE. AGAIN THIS IS A FEW DEGREES BELOW NORMAL.
NICHOLS
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 305 AM CDT WED JUL 31 2013
NORTHWEST FLOW WILL KEEP TEMPERATURES BELOW NORMAL THROUGH THE
EXTENDED PERIOD WITH HIGHS GENERALLY IN THE UPPER 70S TO LOWER 80S
AND LOWS IN THE LOWER TO MID 60S.
THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME MAINLY ON
FRIDAY AND THEN AGAIN SUNDAY NIGHT INTO MONDAY AS SIGNIFICANT WAVES
MOVE ALONG IN THE FLOW.
INTERESTING THAT THE 00Z ECMWF HAS BACKED OFF ON SHOWING A POLAR VORTEX
DIVING INTO NORTHERN MN ON AUGUST 8. IT NOW DEPICTS MORE OF A BROAD
TROF IN THE EASTERN UNITED STATES WITH A 1030 MB HIGH DROPPING INTO
THE UPPER MIDWEST WITH 850 MB TEMPERATURES OF +8C INTO THE DVN CWA.
WE SHALL SEE WHAT THE NEXT RUNS SHOW.
HAASE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 615 AM CDT WED JUL 31 2013
LOW CLOUDS AND AREAS OF FOG WILL DISSIPATE AT ALL THE TERMINALS
BETWEEN 31/12-15Z. THEN...VFR CONDITIONS WILL PREVAIL FOR AT LEAST
THE NEXT 24 HOURS WITH FAIR SKIES AND FEW-SCT COVERAGE OF FAIR
WEATHER CUMULUS CLOUDS WITH BASES AOA 4 K AGL. WINDS WILL BE OUT
OF THE NORTHWEST AT 5 TO 10 MPH OR LESS THROUGH THIS EVENING AND
THEN BECOMING LIGHT TOWARD 01/12Z.
NICHOLS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...HAASE
AVIATION...NICHOLS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1055 AM CDT WED JUL 31 2013
.UPDATE...
ISSUED AT 1055 AM CDT WED JUL 31 2013
WEAK SFC LOW ACROSS THE AREA LATE THIS MORNING...WITH FAIRLY
EXTENSIVE LOWER CLOUD COVER...AND CONVECTION CLOSE TO THE KY/TN
BORDER...MAINLY IN NW TN. LATEST HRRR / NSSL WRF SHOWS VERY
LITTLE CONVECTION ACROSS THE AREA TODAY. WVAPOR SHOWS A VERY
SUBTLE WAVE COMING SE FROM ERN NE AND SRN IA INTO NRN MO.
CONSIDERING THAT THE MESO MODELS DEVELOP INSTABILITY ACROSS
THE AREA TODAY...SOME WEAK SFC CONVERGENCE AS THE LOW DRIFTS
ACROSS THE AREA...AND PERHAPS WEAK UPPER SUPPORT FROM THE TAIL
END OF THE AFOREMENTIONED WAVE...WILL LEAVE AT LEAST SLIGHT
CHANCE POPS FOR CONVECTION GOING THROUGH THE DAY AND MONITOR.
BEST INSTABILITY AT 15Z IS INTO SEMO...WITH SFC LI/S DOWN TO
-4 AND CAPES APPROACHING 2000. TEMPS AND CLOUDS FORECAST WERE
GENERALLY ON TRACK...SO ONLY MINOR TWEAKS THERE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 133 AM CDT WED JUL 31 2013
GFS/NAM/RAP ALL PICK UP ON SHOWERS OVER WKY MOVING EAST WITH DRIER
AIR ALREADY STARTING TO WORK IN FROM THE WEST AND SHUT PCPN
CHANCES OFF OR AT LEAST ON A DOWNWARD TREND. WILL CONTINUE POPS
THRU EARLY TODAY...THEN WANE LATER AS UPPER TROF MAKES PASSAGE AND
SURFACE HIGH PRESSURE TRIES TO BUILD INTO MS VALLEY IN THE WAKE OF
ITS DEPARTURE...BY 00Z THU.
AFOREMENTIONED SURFACE HIGH THEN REALLY SETTLES ACROSS TN VALLEY
AND BECOMES THE WEATHER FEATURE OF NOTE FOR THE ENSUING 24-36
HOURS OR AT LEAST TIL THE NEXT SYSTEM TAKES SHAPE AND MOVES IN ON
FRIDAY. BY THEN THE HIGH HAS SHIFTED EASTWARD ACROSS THE
CUMBERLAND PLATEAU AND A WARM/SOUPY RETURN FLOW DEVELOPS IN
ADVANCE OF AN INCOMING WAVE. THIS WILL TOUCH OFF SHOWER AND STORM
CHANCES BEGINNING FRIDAY AND LASTING INTO THE WEEKEND.
WE`LL SEE TEMPS AND HUMIDITY LEVELS GRADUALLY RETURN TOWARD CLIMO
NORMS HERE IN THE NEXT 24 HOURS AND PERSIST THRU THE REMAINDER OF
THE WORKWEEK.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 245 AM CDT WED JUL 31 2013
AN UNSETTLED PATTERN IS SHAPING UP OVER THE WEEKEND INTO THE FIRST
PART OF NEXT WEEK. THE QUAD STATE REGION WILL REMAIN IN NORTHWEST
FLOW ALOFT...WITH UPPER LEVEL RIDGING OVER THE WESTERN AND SOUTHERN
U.S. AND AN UPPER LEVEL TROUGH IN THE EAST. A BAROCLINIC ZONE IS
EXPECTED TO DEVELOP OVER THE REGION ON SATURDAY AND REMAIN IN CLOSE
PROXIMITY THROUGH MONDAY. THIS WILL HELP TO INCREASE THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS OVER THE WEEKEND...ESPECIALLY SATURDAY
AS A MID LEVEL WAVE PROGRESSES ACROSS THE REGION.
MODELS ARE STILL NOT IN THE BEST AGREEMENT BY SUNDAY AND MONDAY.
SOME MODEL RUNS HAVE TENDED TO SHIFT THE FRONTAL ZONE SOUTH OF THE
AREA BY EARLY IN THE NEW WEEK. OTHERS...HOWEVER...FOCUS ADDITIONAL
ACTIVITY ALONG AND NORTH OF THE BOUNDARY AS IT RETURNS TO THE NORTH
AS A WARM FRONT LATE SUNDAY INTO MONDAY. GIVEN THE LOW CONFIDENCE
FORECAST...WILL KEEP CHANCE PROBABILITIES GOING FOR NOW.
TEMPERATURES THROUGH THE PERIOD WILL BE NEAR IF NOT A FEW DEGREES
BELOW SEASONAL NORMS. EXPECT A SMALLER THAN NORMAL DIURNAL RANGE
WITH THE ANTICIPATED SKY COVER AND PRECIPITATION CHANCES. HUMIDITY
LEVELS WILL BE QUITE HIGH AS WELL WITH DEW POINTS FORECAST IN THE
UPPER 60S TO NEAR 70.
&&
.AVIATION...
ISSUED AT 1055 AM CDT WED JUL 31 2013
WILL MONITOR CONVECTIVE CHANCES THE REST OF THE DAY. GRADUAL
IMPROVEMENT IN CLOUD BASE HEIGHTS AND VSBYS EXPECTED WITH WEAK
MIXING...HEAT OF THE DAY. LOWER CLOUDS MAY LINGER TONIGHT ACROSS
PART OF THE AREA...WITH SOME LIGHT FOG POSSIBLE AS WELL.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...NOLES
AVIATION...NOLES
AREA FORECAST DISCUSSION
NWS JACKSON KY
1130 AM EDT WED JUL 31 2013
.UPDATE...
ISSUED AT 1130 AM EDT WED JUL 31 2013
UPDATED THE FORECAST TO BETTER TIME THE PRECIPITATION INTO THE AREA
BASED ON MODEL SOUNDINGS AND CURRENT RADAR ACTIVITY...DECREASED THE
COVERAGE AND TIMING FOR THUNDERSTORMS TODAY AND TOOK THE THUNDER OUT
OF THE TONIGHT FORECAST. STILL HAVE SOME CONCERN THAT THIS SYSTEM IS
GOING TO STAY FURTHER SOUTH THAN WHAT IS CURRENTLY FORECAST. MAY
HAVE TO DECREASE THE PROBABILITY OF PRECIPITATION FOR AREAS NORTH OF
THE MOUNTAIN PARKWAY. MAKE SOME MORE ADJUSTMENTS DURING THE 2 PM
UPDATE.
UPDATE ISSUED AT 755 AM EDT WED JUL 31 2013
HOURLY TEMP AND DEWPOINTS WERE FRESHENED UP BASED ON RECENT OBS.
UPSTREAM RADAR RETURNS STILL FAVOR HIGHER POPS IN THE FAR SOUTH. NO
SUBSTANTIAL CHANGES WERE MADE AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 340 AM EDT WED JUL 31 2013
A SHORTWAVE IS CURRENTLY WORKING THROUGH THE OH VALLEY REGION IN
WEST NORTHWEST FLOW...BUT IS PRODUCING ONLY LIGHT RAIN SHOWERS
LOCALLY. A RIDGE OF HIGH PRESSURE WAS CENTERED OVER THEE SOUTHERN
ROCKIES WITH AN UPPER LEVEL LOW AND TROUGH CONTINUING TO EXIT THE
NORTHEASTERN CONUS INTO THE MARITIMES. ALSO IN THE NORTHERN
STREAM...A SHORTWAVE TRACKING NEAR THE US/CANADIAN BORDER IS
APPROACHING THE UPPER MS VALLEY AND WESTERN ONTARIO. HEAVIER
PRECIPITATION THUS FAR HAS BEEN CONFINED TO SOUTHERN MIDDLE AND
EASTERN TN AND THE NORTHERN GULF COAST STATES. THERE HAS ALSO BEEN A
SLIGHT INCREASE IN CONVECTION OVER WESTERN KY.
THE SHORTWAVE NOW WORKING THROUGH THE OH VALLEY AND INTO THE
APPALACHIAN REGION AND THE SHORTWAVE WORKING TOWARD THE WESTERN GREAT
LAKES WILL EVENTUALLY BECOME A BIT MORE PHASED BY THUS AND LEAD TO A
RETURN TO A MORE AMPLIFIED EASTERN/NORTHEASTERN CONUS THROUGH AND
ROCKIES/PLAINS RIDGE. MEANWHILE A SFC LOW IS LAGGING THE UPPER LEVEL
SHORTWAVE WORKING THROUGH THE OH VALLEY. THIS LOW WILL DRIFT THROUGH
THE LOWER OH VALLEY REGION AND REACH CENTRAL KY THIS EVENING...EVENTUALLY
BECOMING DIFFUSE AND MORE OR LESS MERGING WITH A COLD FRONT ASSOCIATED
WITH THE TROUGH WORKING THROUGH ONTARIO AND THE GREAT LAKES REGION
TONIGHT AND INTO THURSDAY. THE SFC COLD FRONT SHOULD CROSS THE CWA ON
THURSDAY.
THE 0Z NAM AND THE 4Z HRR GENERALLY INDICATE REDEVELOPMENT OF
STRONGER CONVECTION THAN THE LIGHT SHOWERS CURRENTLY OVER THE CWA
TOWARD DAWN AND THEN WORK THIS INTO EASTERN KY THIS MORNING AND INTO
THIS AFTERNOON. THE NAM HAS BULLSEYE OF QPF OVER THE LAKE CUMBERLAND
REGION...BUT MUCH OF THE OTHER GUIDANCE HAS HIGHER QPF NEAR THE TN
BORDER...AND IS NOT NEARLY AS MUCH. CONFIDENCE IN THE EVOLUTION OF
THIS CONVECTION IS BELOW AVERAGE...BUT THE MODEL CONSENSUS IS THAT
BEST CHANCES SHOULD BE ACROSS THE SOUTH TODAY. THE 5Z HRRR HAS THROWN
A BIT MORE UNCERTAINTY INTO THE PICTURE...ESPECIALLY ACROSS THE NORTH
WITH IT SUGGEST COULD LARGELY REMAIN DRY.
WE HAVE OPTED TO GO VERY CLOSE TO HPC QPF WHICH LED TO LOWER AMOUNTS
THAN THE NAM OVER THE SOUTH WITH THE HIGHEST POPS OVER THE SOUTHERN
CWA. HOWEVER...THIS STILL YIELDS NEARLY AN INCH OF RAIN THROUGH
TONIGHT. ALTHOUGH A SHORTWAVE CURRENTLY WORKING THROUGH THE OH VALLEY
AND ANOTHER UPSTREAM WILL WORK ACROSS THE AREA THIS AFTERNOON AND THE
SFC LOW WILL GRADUALLY APPROACH THE AREA...CLOUD COVER SHOULD LIMIT
OVERALL INSTABILITY. THE CLOSEST LIGHTNING AT PRESENT IS OVER WESTERN
KY. THUS WE HAVE KEPT COVERAGE OF THUNDER AT ISOLATED TO SCATTERED
LEVELS THROUGH THIS EVENING WITH HIGHER COVERAGE OF SHOWERS.
HOWEVER... CHANCES FOR CONVECTION WILL LINGER THROUGH MOST OF THE
PERIOD...UNTIL LATE ON THU WHEN A COLD FRONT WILL SWEEP THE DEEPER
MOISTURE EAST AND SOUTHEAST OF THE AREA.
MOS GUIDANCE WAS TOO WARM WITH HIGHS ON TUE AND WE HAVE WENT ON THE
COLDER END OF GUIDANCE FOR MAX T TODAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 AM EDT WED JUL 31 2013
MODELS ARE AGREEING A BIT MORE HEADING INTO THE UPCOMING
WEEKEND...SO CONFIDENCE IN THE FORECAST IS INCREASING. STARTING
THURSDAY NIGHT...HIGH PRESSURE WILL BE BUILDING INTO THE
REGION...SETTING UP A DRY AND PLEASANT END TO THE WEEK. A SHORTWAVE
TROUGH WILL THEN DRAG A SURFACE WARM FRONT BACK TO THE NORTHEAST
LATE FRIDAY NIGHT INTO SATURDAY WITH ISENTROPIC ASCENT DEVELOPING
OVER THE REGION. THIS WILL YIELD THE POTENTIAL FOR A WET PERIOD ON
SATURDAY...AS THE WARM FRONT STALLS OVER THE AREA. A SECONDARY
SHORTWAVE PUSHING ACROSS THE GREAT LAKES WILL THEN DRAG A COLD FRONT
SOUTHWARD ACROSS THE OHIO RIVER VALLEY SATURDAY NIGHT INTO EARLY
SUNDAY...WITH ANOTHER PERIOD OF UNSETTLED WEATHER EXPECTED. THIS
FRONTAL BOUNDARY WILL GET SHOVED SOUTHWARD ON SUNDAY WITH DRY
WEATHER RETURNING TO FINISH OUT THE WEEKEND. HOWEVER...THE ACTIVE
WEATHER WILL CONTINUE AS ANOTHER SHORTWAVE PUSHES EAST INTO THE AREA
ON MONDAY...BRINGING ANOTHER ROUND OF SHOWERS AND PERHAPS A
THUNDERSTORM TO THE AREA. DRIER WEATHER MAY RETURN BY TUESDAY AND
WEDNESDAY...BUT GIVEN THE TROUGH OVER THE REGION...ADDITIONAL WAVES
OF UNSETTLED WEATHER COULD IMPACT THE REGION. HIGHS THROUGH THE
PERIOD WILL BE A TOUCH BELOW NORMAL WITH A GENERAL TROUGH OVER THE
EASTERN US...KEEPING TEMPERATURES UNUSUALLY COOL FOR THIS TIME OF
YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 755 AM EDT WED JUL 31 2013
UPSTREAM RADAR AND SOME OF THE MODEL GUIDANCE FAVORS CONVECTION OVER
CENTRAL KY WORKING ACROSS THE SOUTHERN PART OF THE CWA THROUGH ABOUT
18Z. THIS WOULD AFFECT LOZ AND SME AND PERHAPS AS FAR NORTH AS JKL.
THE NORTHERN PART OF THE CWA SHOULD EXPERIENCE MORE IN THE WAY OF
SCATTERED CONVECTION. A BIT OF IFR IS POSSIBLE IN ANY THUNDERSTORMS
AFTER 15Z. OTHERWISE...MVR IS EXPECTED MOST OF THE TIME THROUGH 6Z.
THE PCPN THREAT SHOULD DIMINISH LATE IN THE PERIOD AS A COLD FRONT
WORKS INTO THE AREA. SOME LOW CLOUDS NEAR THE FRONT COULD LIMIT VSBY
AND CIG TO IFR OR LOWER...AND PERHAPS BELOW AIRPORT MINS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
800 AM EDT WED JUL 31 2013
.UPDATE...
ISSUED AT 755 AM EDT WED JUL 31 2013
HOURLY TEMP AND DEWPOINTS WERE FRESHENED UP BASED ON RECENT OBS.
UPSTREAM RADAR RETURNS STILL FAVOR HIGHER POPS IN THE FAR SOUTH. NO
SUBSTANTIAL CHANGES WERE MADE AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 340 AM EDT WED JUL 31 2013
A SHORTWAVE IS CURRENTLY WORKING THROUGH THE OH VALLEY REGION IN
WEST NORTHWEST FLOW...BUT IS PRODUCING ONLY LIGHT RAIN SHOWERS
LOCALLY. A RIDGE OF HIGH PRESSURE WAS CENTERED OVER THEE SOUTHERN
ROCKIES WITH AN UPPER LEVEL LOW AND TROUGH CONTINUING TO EXIT THE
NORTHEASTERN CONUS INTO THE MARITIMES. ALSO IN THE NORTHERN
STREAM...A SHORTWAVE TRACKING NEAR THE US/CANADIAN BORDER IS
APPROACHING THE UPPER MS VALLEY AND WESTERN ONTARIO. HEAVIER
PRECIPITATION THUS FAR HAS BEEN CONFINED TO SOUTHERN MIDDLE AND
EASTERN TN AND THE NORTHERN GULF COAST STATES. THERE HAS ALSO BEEN A
SLIGHT INCREASE IN CONVECTION OVER WESTERN KY.
THE SHORTWAVE NOW WORKING THROUGH THE OH VALLEY AND INTO THE
APPALACHIAN REGION AND THE SHORTWAVE WORKING TOWARD THE WESTERN GREAT
LAKES WILL EVENTUALLY BECOME A BIT MORE PHASED BY THUS AND LEAD TO A
RETURN TO A MORE AMPLIFIED EASTERN/NORTHEASTERN CONUS THROUGH AND
ROCKIES/PLAINS RIDGE. MEANWHILE A SFC LOW IS LAGGING THE UPPER LEVEL
SHORTWAVE WORKING THROUGH THE OH VALLEY. THIS LOW WILL DRIFT THROUGH
THE LOWER OH VALLEY REGION AND REACH CENTRAL KY THIS EVENING...EVENTUALLY
BECOMING DIFFUSE AND MORE OR LESS MERGING WITH A COLD FRONT ASSOCIATED
WITH THE TROUGH WORKING THROUGH ONTARIO AND THE GREAT LAKES REGION
TONIGHT AND INTO THURSDAY. THE SFC COLD FRONT SHOULD CROSS THE CWA ON
THURSDAY.
THE 0Z NAM AND THE 4Z HRR GENERALLY INDICATE REDEVELOPMENT OF
STRONGER CONVECTION THAN THE LIGHT SHOWERS CURRENTLY OVER THE CWA
TOWARD DAWN AND THEN WORK THIS INTO EASTERN KY THIS MORNING AND INTO
THIS AFTERNOON. THE NAM HAS BULLSEYE OF QPF OVER THE LAKE CUMBERLAND
REGION...BUT MUCH OF THE OTHER GUIDANCE HAS HIGHER QPF NEAR THE TN
BORDER...AND IS NOT NEARLY AS MUCH. CONFIDENCE IN THE EVOLUTION OF
THIS CONVECTION IS BELOW AVERAGE...BUT THE MODEL CONSENSUS IS THAT
BEST CHANCES SHOULD BE ACROSS THE SOUTH TODAY. THE 5Z HRRR HAS THROWN
A BIT MORE UNCERTAINTY INTO THE PICTURE...ESPECIALLY ACROSS THE NORTH
WITH IT SUGGEST COULD LARGELY REMAIN DRY.
WE HAVE OPTED TO GO VERY CLOSE TO HPC QPF WHICH LED TO LOWER AMOUNTS
THAN THE NAM OVER THE SOUTH WITH THE HIGHEST POPS OVER THE SOUTHERN
CWA. HOWEVER...THIS STILL YIELDS NEARLY AN INCH OF RAIN THROUGH
TONIGHT. ALTHOUGH A SHORTWAVE CURRENTLY WORKING THROUGH THE OH VALLEY
AND ANOTHER UPSTREAM WILL WORK ACROSS THE AREA THIS AFTERNOON AND THE
SFC LOW WILL GRADUALLY APPROACH THE AREA...CLOUD COVER SHOULD LIMIT
OVERALL INSTABILITY. THE CLOSEST LIGHTNING AT PRESENT IS OVER WESTERN
KY. THUS WE HAVE KEPT COVERAGE OF THUNDER AT ISOLATED TO SCATTERED
LEVELS THROUGH THIS EVENING WITH HIGHER COVERAGE OF SHOWERS.
HOWEVER... CHANCES FOR CONVECTION WILL LINGER THROUGH MOST OF THE
PERIOD...UNTIL LATE ON THU WHEN A COLD FRONT WILL SWEEP THE DEEPER
MOISTURE EAST AND SOUTHEAST OF THE AREA.
MOS GUIDANCE WAS TOO WARM WITH HIGHS ON TUE AND WE HAVE WENT ON THE
COLDER END OF GUIDANCE FOR MAX T TODAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 AM EDT WED JUL 31 2013
MODELS ARE AGREEING A BIT MORE HEADING INTO THE UPCOMING
WEEKEND...SO CONFIDENCE IN THE FORECAST IS INCREASING. STARTING
THURSDAY NIGHT...HIGH PRESSURE WILL BE BUILDING INTO THE
REGION...SETTING UP A DRY AND PLEASANT END TO THE WEEK. A SHORTWAVE
TROUGH WILL THEN DRAG A SURFACE WARM FRONT BACK TO THE NORTHEAST
LATE FRIDAY NIGHT INTO SATURDAY WITH ISENTROPIC ASCENT DEVELOPING
OVER THE REGION. THIS WILL YIELD THE POTENTIAL FOR A WET PERIOD ON
SATURDAY...AS THE WARM FRONT STALLS OVER THE AREA. A SECONDARY
SHORTWAVE PUSHING ACROSS THE GREAT LAKES WILL THEN DRAG A COLD FRONT
SOUTHWARD ACROSS THE OHIO RIVER VALLEY SATURDAY NIGHT INTO EARLY
SUNDAY...WITH ANOTHER PERIOD OF UNSETTLED WEATHER EXPECTED. THIS
FRONTAL BOUNDARY WILL GET SHOVED SOUTHWARD ON SUNDAY WITH DRY
WEATHER RETURNING TO FINISH OUT THE WEEKEND. HOWEVER...THE ACTIVE
WEATHER WILL CONTINUE AS ANOTHER SHORTWAVE PUSHES EAST INTO THE AREA
ON MONDAY...BRINGING ANOTHER ROUND OF SHOWERS AND PERHAPS A
THUNDERSTORM TO THE AREA. DRIER WEATHER MAY RETURN BY TUESDAY AND
WEDNESDAY...BUT GIVEN THE TROUGH OVER THE REGION...ADDITIONAL WAVES
OF UNSETTLED WEATHER COULD IMPACT THE REGION. HIGHS THROUGH THE
PERIOD WILL BE A TOUCH BELOW NORMAL WITH A GENERAL TROUGH OVER THE
EASTERN US...KEEPING TEMPERATURES UNUSUALLY COOL FOR THIS TIME OF
YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 755 AM EDT WED JUL 31 2013
UPSTREAM RADAR AND SOME OF THE MODEL GUIDANCE FAVORS CONVECTION OVER
CENTRAL KY WORKING ACROSS THE SOUTHERN PART OF THE CWA THROUGH ABOUT
18Z. THIS WOULD AFFECT LOZ AND SME AND PERHAPS AS FAR NORTH AS JKL.
THE NORTHERN PART OF THE CWA SHOULD EXPERIENCE MORE IN THE WAY OF
SCATTERED CONVECTION. A BIT OF IFR IS POSSIBLE IN ANY THUNDERSTORMS
AFTER 15Z. OTHERWISE...MVR IS EXPECTED MOST OF THE TIME THROUGH 6Z.
THE PCPN THREAT SHOULD DIMINISH LATE IN THE PERIOD AS A COLD FRONT
WORKS INTO THE AREA. SOME LOW CLOUDS NEAR THE FRONT COULD LIMIT VIS
AND CIG TO IFR OR LOWER...AND PERHAPS BELOW AIRPORT MINS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1030 AM CDT WED JUL 31 2013
.UPDATE...MADE MINOR TWEAK TO SKY FCST TODAY AND POPS. MAIN THEME
REMAINS THE PROGRESSION OF THE SFC COLD FRONT SOUTH AND EAST OF THE
CWA THIS AFTERNOON. RW/TRW POTENTIAL REMAINS OVER WISC ZONES WITH
FRONTAL CONVERGENCE/INSTABILITY...AND UNDER STEEPENING LAPSE RATES
OVER NRN MN ZONES. LATEST RAP13 SHOWS AN AREA OF 85/70H LAPSE
RATES OF 6C/KM TO 6.5C/KM PUSHING ACROSS BORDERLAND. DEEP LAYER
MOISTURE IS QUESTIONABLE OVER NWRN CORNER OF CWA. 85/70H RH IS
70 TO 90 PERCENT ACROSS ARROWHEAD SO BETTER CHC APPEARS TO BE IN
THAT LOCATION. PUSHED MAX TEMPS A FEW DEGREES HIGHER NEAR LAKEFRONT
IN DLH VICINITY AS WESTERLY WINDS DOWNSLOPE TO SUPERIOR. GUSTY
WINDS WILL INCREASE TODAY OVER NE MN ZONES AS MIXING LAYER DEEPENS
SIGNIFICANTLY AND TAPS INTO HIGHER WINDS ALOFT.
&&
.PREV DISCUSSION... /ISSUED 647 AM CDT WED JUL 31 2013/
AVIATION...
A COLD FRONT SLOWLY MOVING THROUGH THE REGION TODAY IS EXPECTED TO
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS THROUGH EARLY
AFTERNOON. PATCHY EARLY MORNING FOG IS QUICKLY BURNING OFF...AND
EXPECT VFR CONDITIONS BY 15Z THIS MORNING. KHYR CURRENTLY HAS LIFR
CONDITIONS IN FOG AND STRATUS...AND WILL TAKE A LITTLE LONGER TO
IMPROVE TO VFR. AFTERWARDS...MAINLY VFR CONDITIONS EXPECTED THROUGH
THE PERIOD. THOUGH CONVECTION EXPECTED UNTIL LATE AFTERNOON OR
EARLY EVENING...COVERAGE EXPECTED TO BE QUITE LOW AND POTENTIAL
FOR A PARTICULAR TERMINAL TO BE AFFECTED KIND OF LOW. WILL HAVE TO
MONITOR FOR LATER UPDATES. BEHIND FRONT...GUSTY WNW TO NW WINDS
WILL DEVELOP BY LATE AFTERNOON IN THE WAKE OF THE COLD FRONT. VFR
CONDITIONS ARE EXPECTED THROUGH THIS EVENING AND OVERNIGHT TONIGHT.
PREV DISCUSSION... /ISSUED 356 AM CDT WED JUL 31 2013/
SHORT TERM...TODAY THROUGH THURSDAY.
AT 330 AM...ISOLATED SHOWERS AND THUNDERSTORMS WERE DEVELOPING
ACROSS THE REGION. THE STRONGEST STORM WAS MOVING QUICKLY TOWARD
THE WESTERN PORTION OF THE CWA...SPECIFICALLY CASS COUNTY.
TEMPERATURES AT 3 AM RANGED FROM THE MID 50S TO THE MID 60S.
PATCHY FOG ALSO WAS FOUND ACROSS THE CWA. THERE HAS BEEN SOME
IMPROVEMENT AS THICKER CLOUDS HAVE MOVED IN.
THE MAIN FOCUS FOR TODAY IS ON THUNDERSTORM POTENTIAL. A FRONTAL
BOUNDARY WILL CONTINUE TO MOVE TO THE SOUTH AND EAST ACROSS THE
REGION TODAY...WITH ISOLATED THUNDERSTORMS DEVELOPING ALONG AND
AHEAD OF THE FRONT. IN ADDITION...ANOTHER TROUGH WILL FOLLOW
BEHIND THE FRONT. TOUGH TO PUT TOO MUCH INTO TIMING TODAY BUT
THINK ISOLATED WORDING WILL COVER IT WELL. IN ADDITION...THERE
SHOULD BE SOME DIURNAL SHOWERS AND STORMS ACROSS THE NORTH BY THIS
AFTERNOON. THE HRRR...4 KM NMM AND RAP ARE ALL INDICATING THAT
THERE WILL BE SOME DEVELOPMENT DUE TO DAYTIME HEATING WITH SOME
WEAK INSTABILITY BY THIS AFTERNOON. THE BEST CHANCE FOR SEEING
SOME STRONGER STORMS IS IN EC MN AND NW WI...WHERE SPC HAS A 5
PERCENT WIND AND HAIL CONTOUR.
WITH THE LOSS OF DAYTIME HEATING WE SHOULD SEE A QUICK DEMISE TO
THE SHOWERS AND THUNDERSTORMS TONIGHT. WITH COLD AIR ALOFT AND AN
UPPER LEVEL SHORTWAVE AND VORT MAX...WE SHOULD SEE MORE DIURNAL
ACTIVITY ON THURSDAY SO WILL CONTINUE WITH SMALLER POPS ACROSS
MUCH OF THE AREA BY AFTERNOON.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
THURSDAY NIGHT A WEAK TROUGH AXIS CONTINUES TO MOVE ACROSS THE
FORECAST AREA AS A SHORTWAVE MOVES THROUGH THE UPPER FLOW. SOME
MODELS ARE GENERATING A NICE MCS OVER THE FORECAST AREA AND THEN
DRIVING IT SOUTHEAST ALONG WITH THE UPPER LEVEL FLOW. BETTER
INSTABILITY WILL BE FARTHER SOUTH ALONG THE STRONGER BAROCLINIC ZONE
ACROSS SOUTH DAKOTA EXTENDING INTO IOWA...SO AM NOT TERRIBLY EXCITED
ABOUT ANYTHING SIGNIFICANT THURSDAY NIGHT...BUT AM CARRYING SOME
CHANCE POPS FOR AT LEAST A PORTION OF THE AREA. MUCH IS GOING TO
DEPEND ON THE TIMING OF THE SHORTWAVE WHICH IS HANDLED IN VARYING
WAYS BY THE MODELS THIS MORNING. MIN TEMPS TO BE KEPT MILD BY EXTRA
CLOUD COVER...AND WILL BE MAINLY IN THE 50S.
FRIDAY THROUGH MOST OF SUNDAY A STRONG SURFACE RIDGE BUILDS INTO
THE REGION. ON FRIDAY BEFORE THE RIDGE GETS FIRMLY ESTABLISHED HAVE
SOME SLIGHT CHANCE POPS AS CYCLONIC FLOW ALOFT INTERACTS WITH SOME
LINGERING LOW LEVEL MOISTURE AND CONVERGENCE. TEMPERATURES COOL OFF
FAIRLY SIGNIFICANTLY BY FRIDAY NIGHT AND SATURDAY...WITH ANOTHER
NIGHT WITH SOME 40S ALL THREE NIGHTS...AND HIGHS ONLY IN THE LOW 70S
SATURDAY.
LATE SUNDAY...SUNDAY NIGHT AND MONDAY THINGS BEGIN TO SHIFT AS ANOTHER
SHORTWAVE DIVES THROUGH THE UPPER LEVEL FLOW AND THE SURFACE RIDGE
SHIFTS EAST OF THE AREA. THIS ALLOWS THE BAROCLINIC ZONE TO SHIFT
NORTH INTO SOUTH DAKOTA AND SOUTHERN MINNESOTA...AND WITH THE UPPER
LEVEL JET OVER NORTHERN MINNESOTA BY SUNDAY NIGHT AN MCS CAN BE
EXPECTED TO GENERATE SOMEWHERE NEAR OR SOUTH OF THE FORECAST AREA
THAT NIGHT. HOWEVER...AM NOT TOO CONVINCED IT WILL BE THIS FAR
NORTH AND HAVE LIMITED HIGHER POPS TO THE SOUTHERN COUNTIES WITH
LESS ACROSS THE NORTH. TEMPERATURES REMAIN COOL WITH HIGHS IN THE
LOW 70S. THE NORTHWEST FLOW CONTINUES INTO TUESDAY AND THERE ARE
SOME INDICATIONS THAT WE WILL HAVE ANOTHER SHORTWAVE DUE THROUGH
WITH ANOTHER CHANCE OF PRECIPITATION...BUT CONFIDENCE IS NOT VERY
HIGH AT THIS TIME AND HAVE LIMITED POPS. TEMPERATURES TO REMAIN
NEAR OR SLIGHTLY BELOW NORMAL.
&&
.POINT TEMPS/POPS...
DLH 76 53 74 55 / 20 10 20 10
INL 71 49 74 51 / 20 20 30 20
BRD 76 52 76 55 / 20 10 10 10
HYR 79 50 76 53 / 20 10 20 20
ASX 76 52 75 54 / 20 20 20 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...CANNON
AREA FORECAST DISCUSSION
NWS DULUTH MN
647 AM CDT WED JUL 31 2013
.AVIATION...
A COLD FRONT SLOWLY MOVING THROUGH THE REGION TODAY IS EXPECTED TO
BRING SCATTERED SHOWERS AND A FEW THUNDERSTORMS THROUGH EARLY
AFTERNOON. PATCHY EARLY MORNING FOG IS QUICKLY BURNING OFF...AND
EXPECT VFR CONDITIONS BY 15Z THIS MORNING. KHYR CURRENTLY HAS LIFR
CONDITIONS IN FOG AND STRATUS...AND WILL TAKE A LITTLE LONGER TO
IMPROVE TO VFR. AFTERWARDS...MAINLY VFR CONDITIONS EXPECTED THROUGH
THE PERIOD. THOUGH CONVECTION EXPECTED UNTIL LATE AFTERNOON OR
EARLY EVENING...COVERAGE EXPECTED TO BE QUITE LOW AND POTENTIAL
FOR A PARTICULAR TERMINAL TO BE AFFECTED KIND OF LOW. WILL HAVE TO
MONITOR FOR LATER UPDATES. BEHIND FRONT...GUSTY WNW TO NW WINDS
WILL DEVELOP BY LATE AFTERNOON IN THE WAKE OF THE COLD FRONT. VFR
CONDITIONS ARE EXPECTED THROUGH THIS EVENING AND OVERNIGHT TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 356 AM CDT WED JUL 31 2013/
SHORT TERM...TODAY THROUGH THURSDAY.
AT 330 AM...ISOLATED SHOWERS AND THUNDERSTORMS WERE DEVELOPING
ACROSS THE REGION. THE STRONGEST STORM WAS MOVING QUICKLY TOWARD
THE WESTERN PORTION OF THE CWA...SPECIFICALLY CASS COUNTY.
TEMPERATURES AT 3 AM RANGED FROM THE MID 50S TO THE MID 60S.
PATCHY FOG ALSO WAS FOUND ACROSS THE CWA. THERE HAS BEEN SOME
IMPROVEMENT AS THICKER CLOUDS HAVE MOVED IN.
THE MAIN FOCUS FOR TODAY IS ON THUNDERSTORM POTENTIAL. A FRONTAL
BOUNDARY WILL CONTINUE TO MOVE TO THE SOUTH AND EAST ACROSS THE
REGION TODAY...WITH ISOLATED THUNDERSTORMS DEVELOPING ALONG AND
AHEAD OF THE FRONT. IN ADDITION...ANOTHER TROUGH WILL FOLLOW
BEHIND THE FRONT. TOUGH TO PUT TOO MUCH INTO TIMING TODAY BUT
THINK ISOLATED WORDING WILL COVER IT WELL. IN ADDITION...THERE
SHOULD BE SOME DIURNAL SHOWERS AND STORMS ACROSS THE NORTH BY THIS
AFTERNOON. THE HRRR...4 KM NMM AND RAP ARE ALL INDICATING THAT
THERE WILL BE SOME DEVELOPMENT DUE TO DAYTIME HEATING WITH SOME
WEAK INSTABILITY BY THIS AFTERNOON. THE BEST CHANCE FOR SEEING
SOME STRONGER STORMS IS IN EC MN AND NW WI...WHERE SPC HAS A 5
PERCENT WIND AND HAIL CONTOUR.
WITH THE LOSS OF DAYTIME HEATING WE SHOULD SEE A QUICK DEMISE TO
THE SHOWERS AND THUNDERSTORMS TONIGHT. WITH COLD AIR ALOFT AND AN
UPPER LEVEL SHORTWAVE AND VORT MAX...WE SHOULD SEE MORE DIURNAL
ACTIVITY ON THURSDAY SO WILL CONTINUE WITH SMALLER POPS ACROSS
MUCH OF THE AREA BY AFTERNOON.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
THURSDAY NIGHT A WEAK TROUGH AXIS CONTINUES TO MOVE ACROSS THE
FORECAST AREA AS A SHORTWAVE MOVES THROUGH THE UPPER FLOW. SOME
MODELS ARE GENERATING A NICE MCS OVER THE FORECAST AREA AND THEN
DRIVING IT SOUTHEAST ALONG WITH THE UPPER LEVEL FLOW. BETTER
INSTABILITY WILL BE FARTHER SOUTH ALONG THE STRONGER BAROCLINIC ZONE
ACROSS SOUTH DAKOTA EXTENDING INTO IOWA...SO AM NOT TERRIBLY EXCITED
ABOUT ANYTHING SIGNIFICANT THURSDAY NIGHT...BUT AM CARRYING SOME
CHANCE POPS FOR AT LEAST A PORTION OF THE AREA. MUCH IS GOING TO
DEPEND ON THE TIMING OF THE SHORTWAVE WHICH IS HANDLED IN VARYING
WAYS BY THE MODELS THIS MORNING. MIN TEMPS TO BE KEPT MILD BY EXTRA
CLOUD COVER...AND WILL BE MAINLY IN THE 50S.
FRIDAY THROUGH MOST OF SUNDAY A STRONG SURFACE RIDGE BUILDS INTO
THE REGION. ON FRIDAY BEFORE THE RIDGE GETS FIRMLY ESTABLISHED HAVE
SOME SLIGHT CHANCE POPS AS CYCLONIC FLOW ALOFT INTERACTS WITH SOME
LINGERING LOW LEVEL MOISTURE AND CONVERGENCE. TEMPERATURES COOL OFF
FAIRLY SIGNIFICANTLY BY FRIDAY NIGHT AND SATURDAY...WITH ANOTHER
NIGHT WITH SOME 40S ALL THREE NIGHTS...AND HIGHS ONLY IN THE LOW 70S
SATURDAY.
LATE SUNDAY...SUNDAY NIGHT AND MONDAY THINGS BEGIN TO SHIFT AS ANOTHER
SHORTWAVE DIVES THROUGH THE UPPER LEVEL FLOW AND THE SURFACE RIDGE
SHIFTS EAST OF THE AREA. THIS ALLOWS THE BAROCLINIC ZONE TO SHIFT
NORTH INTO SOUTH DAKOTA AND SOUTHERN MINNESOTA...AND WITH THE UPPER
LEVEL JET OVER NORTHERN MINNESOTA BY SUNDAY NIGHT AN MCS CAN BE
EXPECTED TO GENERATE SOMEWHERE NEAR OR SOUTH OF THE FORECAST AREA
THAT NIGHT. HOWEVER...AM NOT TOO CONVINCED IT WILL BE THIS FAR
NORTH AND HAVE LIMITED HIGHER POPS TO THE SOUTHERN COUNTIES WITH
LESS ACROSS THE NORTH. TEMPERATURES REMAIN COOL WITH HIGHS IN THE
LOW 70S. THE NORTHWEST FLOW CONTINUES INTO TUESDAY AND THERE ARE
SOME INDICATIONS THAT WE WILL HAVE ANOTHER SHORTWAVE DUE THROUGH
WITH ANOTHER CHANCE OF PRECIPITATION...BUT CONFIDENCE IS NOT VERY
HIGH AT THIS TIME AND HAVE LIMITED POPS. TEMPERATURES TO REMAIN
NEAR OR SLIGHTLY BELOW NORMAL.
&&
.POINT TEMPS/POPS...
DLH 76 53 74 55 / 20 20 20 20
INL 71 49 74 51 / 20 20 30 10
BRD 76 52 76 55 / 20 10 10 10
HYR 79 50 76 53 / 20 20 20 30
ASX 76 52 75 54 / 20 20 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...LE
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
629 AM CDT WED JUL 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT WED JUL 31 2013
TODAY AND TONIGHT...HIGH PRESSURE HAS BUILT INTO SCNTL NEB IN WAKE
OF LAST NIGHTS CRUSHING TSTM EVENT. ALL INDICATIONS ARE THE
ATMOSPHERE WILL REMAIN NEARLY QUIET THIS AFTERNOON AND THIS EVENING.
THERE IS PERHAPS THE POTENTIAL FOR DESTABILIZATION THIS AFTN ACROSS
THE CNTL HIGH PLAINS. ISOLATED STORMS COULD DEVELOP ACROSS WRN NEB
WHICH WOULD MOVE EAST AND DISSIPATE IN THE EVENING ACROSS NCNTL NEB.
THERE IS ALSO THE POTENTIAL FOR DESTABILIZATION ACROSS SWRN AND
SCNTL NEB THIS AFTN AND THIS EVENING NORTH OF A SFC FRONT CURRENTLY
LOCATED ACROSS KS AND NERN COLORADO. SPC HAS OUTLOOKED FRONTIER
COUNTY NORTHEAST THROUGH CUSTER AND HOLT COUNTIES IN THEIR DAY 1
OUTLOOK FOR SEVERE TSTM DEVELOPMENT.
FOR THIS MORNING...A CLUSTER OF SHOWERS AND TSTMS ACROSS SWRN SD
COULD SWEEP EAST AND SOUTHEAST THROUGH PARTS OF NWRN AND NCNTL NEB.
THIS IS HIGHLY SPECULATIVE GIVEN THE MODEL DYNAMIC ADJUSTMENT
PROCESS DURING THE FIRST 12 HRS. THE RAP AND HRRR HAVE THEIR OWN
IDEAS. THE RAP SHOWS SCATTERED STORM COVERAGE ACROSS NCNTL NEB WHILE
THE HRRR IS SLOWER AND FARTHER EAST JUST BRUSHING HOLT AND BOYD
COUNTIES. THE FCST IS FOR ISOLATED SHRA/TSTM COVERAGE GIVEN CURRENT
RADAR TRENDS.
TEMPERATURES TODAY ARE ON THE COOL SIDE OF AN ENVELOP OF MID 70S TO
NEAR 90. A BLEND OF MODEL DATA PLUS BIAS CORRECTION YIELDED LOW TO
UPPER 80S FOR HIGHS UNDER SCATTERED AND BROKEN CLOUD COVER.
LASTLY...THE MODELS CONTINUE TO ADVERTISE A LATE NIGHT MCS DROPPING
THROUGH NWRN NEB AROUND 06Z AND THEN PEDDLING EAST AND SOUTHEAST
THROUGH MUCH OF NCNTL NEB BETWEEN 06Z AND 12Z. THE 06Z NAM SHOWS
MODEST ELEVATED CAP AROUND 1000 J/KG AND AN MCS DROPPING MORE SOUTH
THROUGH SCNTL NEB BY 12Z. GIVEN THE TRACK OF THE STORMS TUESDAY
EVENING THIS SOLN HAS SOME CREDIBILITY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 349 AM CDT WED JUL 31 2013
ACTIVE WEATHER TO CONTINUE THROUGH THE PERIOD. A WARM FRONT WILL
EXTEND WEST TO EAST ACROSS THE AREA THURSDAY AND BE THE FOCUS FOR
TSTM DEVELOPMENT. CONTINUED NORTHWEST FLOW ALOFT WILL COMBINE WITH
EAST TO SOUTHEAST WINDS AT THE SFC...PRODUCING FAVORABLE SHEAR FOR
SUPERCELL TSTMS WITH LARGE HAIL AND DAMAGING WIND POTENTIAL. WILL
ALSO HAVE TO WATCH FOR HEAVY RAIN/FLOODING POTENTIAL...AS SOME AREAS
HAVE RECEIVED WELL OVER TWO INCHES OF RAIN THE LAST FEW DAYS.
VALENTINE FOR INSTANCE HAD OVER TWO INCHES OF RAIN JUST LAST
NIGHT.
THE AFOREMENTIONED FRONT WILL REMAIN IN THE AREA FRIDAY THROUGH THE
UPCOMING WEEKEND...AND CONTINUE TO BE THE FOCUS FOR AT LEAST
SCATTERED TSTM DEVELOPMENT. RICH MOISTURE...SHEAR...AND
INSTABILITY...WILL CONTINUE TO BRING THE THREAT FOR A FEW SEVERE
STORMS AS WELL AS LOCALIZED HEAVY RAIN.
BY EARLY NEXT WEEK...HIGH PRESSURE WILL TRY TO NUDGE SOUTH INTO THE
AREA FROM THE NORTHERN PLAINS/CANADA. THIS MAY FORCE THE RICHER
MOISTURE SOUTH INTO KANSAS AND OKLAHOMA...BUT STILLS APPEARS TO BE
ENOUGH MOISTURE IN THE AREA TO CONTINUE SOME SLIGHT AND LOW END
CHANCES FOR TSTM ACTIVITY.
TEMPERATURE WISE...WITH THE FRONT REMAINING IN THE AREA...ALONG WITH
CLOUDS AND PRECIPITATION FROM TIME TO TIME...HIGHS WILL REMAIN
GENERALLY IN THE 80S. OVERNIGHT LOWS WILL BE MILD WITH THE INCREASED
MOISTURE CONTENT IN THE AIR...WITH MOST LOCALS REMAINING IN THE 60S
AT NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 622 AM CDT WED JUL 31 2013
A BANK OF MVFR/LOCAL IFR HAS DEVELOPED ACROSS PARTS OF WRN NEB. THIS
BANK OF CLOUDS SHOULD LIFT TO VFR AROUND 15Z-17Z. ISOLATED
SHRA/TSTMS CONTINUE TO FIRE...MAINLY EAST OF HIGHWAY 83 THIS
MORNING. THIS INSTABILITY IS EXPECTED TO SHIFT EAST AND SOUTH AND
BECOME THE FORCING MECHANISM FOR SCATTERED SEVERE THUNDERSTORMS
THIS AFTN FROM FRONTIER COUNTY NORTHEAST THROUGH CUSTER AND HOLT
COUNTIES. CONFIDENCE IS ON THE LOW SIDE WITH THIS AS NEITHER THE
HRRR OR RAP MODELS SHOW MUCH FORMING THROUGH 23Z. ALSO...ISOLATED
TSTMS MAY FORM ACROSS WRN NEB LATE THIS AFTERNOON OR THIS EVENING.
THE MOST SIGNIFICANT CONVECTION IS EXPECTED TO FORM LATE TONIGHT
WITH STORMS DEVELOPING ACROSS THE CNTL HIGH PLAINS...BETWEEN 03Z-
06Z AND SPINNING SOUTH AND EAST THROUGH WRN AND NCNTL NEB THROUGH
12Z THURSDAY. NOTE THAT THE NAM SHOWS TWO ROUNDS OF STORMS RIPPING
THROUGH THE FCST AREA AND THIS SEEMS CREDIBLE GIVEN THE VERY ACTIVE
WEATHER PATTERN UNDERWAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BUFFALO NY
948 AM EDT WED JUL 31 2013
.SYNOPSIS...
HIGH PRESSURE PUSHING EAST ACROSS NEW YORK AND PENNSYLVANIA WILL
BRING DRY WEATHER AND SEASONABLE TEMPERATURES TO THE AREA TODAY.
MEANWHILE...MOISTURE ASSOCIATED WITH A PASSING COLD FRONT WILL BRING
A GOOD CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS TONIGHT AND
THURSDAY. LINGERING MOISTURE AND SOMEWHAT UNSTABLE AIR BEHIND THE
FRONT MAY BRING A FEW MORE SHOWERS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE CENTERED OVER NEW YORK AND PA WILL PROVIDE US WITH
DRY WEATHER AND SEASONABLE TEMPERATURES TODAY. THERE WILL BE A
GRADUAL INCREASE IN MID AND HIGH LEVEL CLOUDS AS MOISTURE
ASSOCIATED WITH WARM AIR ADVECTION OVER THE OHIO VALLEY AND
CENTRAL GREAT LAKES MOVES SLOWLY TO THE EAST. REGIONAL RADARS SHOW
AN EXPANDING AREA OF SHOWERS OVER MICHIGAN AND CENTRAL
OHIO...MOVING SLOWLY TO THE EAST. THE EASTERN EDGE OF THIS PCPN
MAY REACH FAR WESTERN NEW YORK LATE IN THE DAY...BUT THE REST OF
THE AREA SHOULD STAY DRY.
A LIGHT SOUTHERLY FLOW AHEAD OF THE MIDWEST COLD FRONT FRONT WILL
ALLOW TEMPERATURES TO WARM GENERALLY INTO THE MID AND UPPER 70S
DURING THE AFTERNOON...WITH A FEW SPOTS ACROSS THE GENESEE VALLEY
AND FINGER LAKES POSSIBLY WARMING INTO THE LOWER 80S...DEPENDING ON
HOW EXTENSIVE THE MID LEVEL CLOUDS BECOME.
CONDITIONS WILL DETERIORATE THIS EVENING AND TONIGHT AS MOISTURE
DEEPENS AHEAD OF THE APPROACHING COLD FRONT. THE LATEST GUIDANCE
STILL SHOWS STRONG FRONTOGENETIC FORCING IN THE MID LEVELS OF THE
ATMOSPHERE...WHILE A DECENT UPPER LEVEL JET LIFTS NORTH INTO WESTERN
QUEBEC. AS THESE SOURCES OF FAVORABLE LIFT INTERACT WITH THE
INCREASING MOISTURE...A PERIOD OF MODERATE RAIN IS POSSIBLE
...ESPECIALLY DURING THE SECOND HALF OF THE NIGHT. WHILE THE NAM AND
GFS QPF OUTPUTS APPEAR TO BE SUFFERING FROM CONVECTIVE FEEDBACK...A
SOLID HALF INCH OF RAIN IS POSSIBLE ACROSS PARTS OF WESTERN NEW YORK
BEFORE DAYBREAK.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THE LONGWAVE PATTERN THAT WE WILL BE IN DURING THE NEXT WEEK TO TEN
DAYS IS ONE THAT SNOW LOVERS DREAM OF HAVING DURING THE WINTER
MONTHS...BUT ALAS...THEY WILL HAVE TO BE CONTENT WITH COMFORTABLY
COOL LATE SUMMER CONDITIONS. A DEEP TROUGH WILL BE RE-ESTABLISHED
ACROSS EASTERN CANADA AND THE GREAT LAKES REGION AT THE START OF
THIS PERIOD...WITH ADDITIONAL SHORTWAVE ENERGY DIVING INTO ITS BASE
AND THE BUILDING OF A GREENLAND BLOCK INSURING THAT THE HIGH
AMPLITUDE BLOCKING PATTERN WILL BE ANCHORED IN PLACE FOR SOME TIME
TO COME. THIS GENERAL LONGWAVE PATTERN IS STRONGLY SUPPORTED BY ALL
MEDIUM RANGE ENSEMBLE PACKAGES AS WELL AS CPC FORECASTS OF
HEMISPHERIC PROCESSES...LIKE THE NAO AND PNA. MORE ON THIS IN THE
LONG RANGE DISCUSSION BELOW. NOW FOCUSING IN ON THE DETAILS...
A COLD FRONT WILL MARCH ACROSS OUR FORECAST AREA ON THURSDAY...
WITH WIDESPREAD SHOWERS AND POSSIBLY A FEW EMBEDDED THUNDERSTORMS
EXPECTED AS A RESULT. THE GUIDANCE PACKAGES HAVE BEEN DEPICTING A
PROGRESSIVELY EARLIER ONSET OF PCPN FOR THE PAST SEVERAL RUNS...AND
IT SEEMS AS IF THIS IS TIED DIRECTLY TO THE SPEED AND PLACEMENT OF
THE FAVORABLE UPPER LEVEL LIFT SUPPLIED BY A 100KT H25 JET OVER
WESTERN QUEBEC. A 3 TO 5 HOUR PERIOD OF SHOWERS WILL BE ASSOCIATED
WITH THE LIFT FOUND WITHIN THE RR ENTRANCE REGION OF THIS JET...
WITH LINGERING SHOWERS FOUND BACK IN THE VCNTY OF THE LOW LEVEL
FORCING NEAR THE FRONT. THIS WILL BOIL DOWN TO THE BULK OF THE
SHOWERS COMING DURING THE MORNING HOURS FOR THE WRN COUNTIES...AND
DURING THE MIDDAY FOR SITES EAST OF LK ONTARIO. THE SHOWERS WILL
THUS QUICKLY TAPER OFF FROM WEST TO EAST DURING THE COURSE OF THE
AFTERNOON. HAVE RAISED POPS TO 90 REGIONWIDE WITH BASIN AVERAGE QPF
RANGING FROM A QUARTER TO A HALF INCH.
BY THURSDAY EVENING...THE PLUME OF DEEP MOISTURE AHEAD OF THE
FRONT WILL BE RACING ACROSS NEW ENGLAND WHILE THE ACTUAL SFC FRONT
WILL ONLY BE SLOWLY MAKING ITS WAY ACROSS THE EASTERN LAKE ONTARIO
REGION. THIS WILL KEEP THE LIKELIHOOD FOR SOME SHOWERS OVER THE
EASTERN FINGER LAKES AND FOR SITES EAST OF LK ONTARIO...WITH JUST
SPOTTY LIGHT SHOWERS POSSIBLE UNDER A PASSING SHORTWAVE ACROSS THE
WRN COUNTIES. THE TREND WILL DEFINTIELY BE TOWARDS DRIER WEATHER
THOUGH AS LOW LEVEL RIDGING WILL BUILD EAST FROM LOWER MICHIGAN AND
THE OHIO VALLEY.
ANOTHER ISSUE TO KEEP AN EYE ON WILL BE MARGINALLY FAVORABLE
CONDITIONS FOR NUISANCE LAKE EFFECT DURING THE WEE HOURS OF
FRIDAY MORNING. H85 TEMPS ARE FORECAST TO DROP TO AROUND 10C BY
DAYBREAK...AND WITH LK SFC TEMPS IN THE VCNTY OF 22C...THAT WOULD
ONLY SUPPORT WEAK INSTABILITY. THERE WILL ALSO BE LIMITED SYNOPTIC
MOISTURE TO WORK WITH...SO WILL CONTINUE SLGT CHC POPS EAST OF LK
ERIE AND LOW CHC POPS EAST OF LK ONTARIO FOR ANY MINOR LAKE
RESPONSE.
ON FRIDAY AND FRIDAY NIGHT...A SERIES OF WEAK SHORT WAVES WILL
ROTATE THROUGH THE BASE OF THE UPPER LEVEL TROUGH THAT WILL BE
FIRMLY ESTABLISHED OVER THE GREAT LAKES. WHILE THE VAST MAJORITY OF
THIS 24 HOUR PERIOD SHOULD BE RAIN FREE...SCATTERED LIGHT SHOWERS
WILL BE POSSIBLE. THE COMBINATION OF LATE SUMMER HEATING DURING THE
MIDDAY/AFTERNOON WILL COMBINE WITH A SEASONABLY COOL AIRMASS TO
GENERATE LOW LEVEL LAPSE RATES OF 9-10 DEG C/KM...AND THIS ALONG
WITH THE FORCING FROM THE AFOREMENTIONED SHORTWAVE SHOULD BE ENOUGH
TO SUPPORT CHC POPS THROUGH THE EVENING HOURS. THE OVERNIGHT SHOULD
LARGELY BE RAIN FREE...WITH ONLY CHC POPS EAST OF LK ONTARIO FOR
SOME LAKE EFFECT. TEMPS FRIDAY WILL AVERAGE ABOUT 5 DEG F BELOW
NORMAL WITH AFTERNOON HIGHS GENERALLY IN THE MID 70S.
SATURDAY SHOULD BE A FAIRLY NICE DAY...ALBEIT IT SEASONABLY COOL AS
SFC HIGH PRESSURE CENTERED OVER THE CANADIAN PRAIRIES WILL BUILD
SOUTHEAST ACROSS ALL OF THE GREAT LAKES. THIS SHOULD ENCOURAGE
PARTIAL SUNSHINE ACROSS THE REGION WITH H85 TEMPS HOLDING MAX TEMPS
IN THE LOW TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
ALL OF THE THE MEDIUM RANGE ENSEMBLES REMAIN IN STRONG AGREEMENT
THAT THE DEEP...UPPER LEVEL TROUGH WILL HOLD IN PLACE ACROSS EASTERN
NORTH AMERICA THROUGH MUCH IF NOT ALL OF NEXT WEEK. THIS SCENARIO
WILL GUARANTEE THAT WE WILL CONTINUE TO EXPERIENCE BELOW NORMAL
TEMPERATURES...ALTHOUGH NOT ANOMALOUSLY SO AS MERCURY LEVELS WILL
GENERALLY AVERAGING 3-5 DEG F BELOW NORMAL.
IN TERMS OF PCPN...THE BULK OF THIS TIME PERIOD WILL BE RAINFREE.
BESIDES THE LOW CHC FOR NUISANCE LAKE SHOWERS SOUTHEAST OF LK
ONTARIO...CANADIAN HIGH PRESSURE BUILDING ACROSS THE LOWER GREAT
SHOULD PROVIDE THE REGION WITH DRY WEATHER SUNDAY AND MONDAY. THE
ECMWF HAS BECOME THE OUTLIER ON SUNDAY IN THAT IT SUGGESTS THAT A
VIGOROUS SHORTWAVE WILL GENERATE SOME SHOWERS...BUT THIS IS A NEW
SOLUTION AND ONE THAT IS NOT SUPPORTED BY OTHER PACKAGES.
THE POTENTIAL FOR A FAIRLY POTENT SHORTWAVE AND ASSOCIATED SFC WAVE
TO PASS THROUGH THE REGION ON TUESDAY WILL NECESSITATE THE
INTRODUCTION OF CHC POPS.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
PATCHY FOG ACROSS THE SOUTHERN TIER WILL BURN OFF BY MID MORNING.
OTHERWISE...HIGH PRESSURE CENTERED OVER NY AND PA WILL MAINTAIN VFR
CONDITIONS ACROSS THE AREA TODAY. THERE WILL BE AN INCREASE IN MID
AND HIGH LEVEL CLOUDS LATER THIS MORNING AND DURING THE AFTERNOON AS
MOISTURE DEVELOPING AHEAD OF THE MIDWEST COLD FRONT MOVES SLOWLY TO
THE EAST.
SHOWERS AND POSSIBLE THUNDERSTORMS WILL THEN SPREAD ACROSS THE AREA
THIS EVENING AND TONIGHT AS THE APPROACHING FRONT INTERACTS WITH
INCREASING MOISTURE LIFTING NORTH FROM THE OHIO VALLEY. WITH MORE
WIDESPREAD SHOWERS...CONDITIONS WILL GRADUALLY LOWER TO MVFR BEFORE
DAYBREAK AT MOST TAF SITES WEST OF KART.
OUTLOOK...
THURSDAY...VFR/MVFR WITH SHOWERS AND A FEW SCATTERED THUNDERSTORMS
PRODUCING ASSOCIATED BRIEF IFR.
FRIDAY AND SATURDAY...MAINLY VFR WITH A SMALL CHANCE OF SHOWERS.
SUNDAY...VFR.
&&
.MARINE...
A RELATIVELY WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE ACROSS THE
LOWER LAKES TODAY AND TONIGHT. AFTER A FRONT CROSSES THE LAKES ON
THURSDAY...THE WINDS WILL SWITCH TO THE SOUTHWEST AND PICK UP A
BIT...BUT CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA. MORE IMPORTANTLY...THE FRONT WILL BRING A GOOD
CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS TONIGHT AND
THURSDAY...WITH LOCAL INCREASES IN WIND AND WAVES POSSIBLE.
THE PRESSURE GRADIENT BETWEEN BETWEEN A SURFACE HIGH OVER THE MIDDLE
ATLANTIC STATES AND LOW PRESSURE PUSHING ACROSS HUDSON BAY WILL
CAUSE WESTERLY WINDS TO PICK UP A LITTLE MORE ON FRIDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TJP
NEAR TERM...LEVAN/TJP
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...LEVAN/TJP
MARINE...LEVAN/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
717 AM EDT WED JUL 31 2013
.SYNOPSIS...
HIGH PRESSURE PUSHING EAST ACROSS NEW YORK AND PENNSYLVANIA WILL
BRING DRY WEATHER AND SEASONABLE TEMPERATURES TO THE AREA TODAY.
MEANWHILE...MOISTURE ASSOCIATED WITH A PASSING COLD FRONT WILL BRING
A GOOD CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS TONIGHT AND
THURSDAY. LINGERING MOISTURE AND SOMEWHAT UNSTABLE AIR BEHIND THE
FRONT MAY BRING A FEW MORE SHOWERS ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
PATCHY FOG ACROSS THE SOUTHERN TIER WILL DISSIPATE BY MID
MORNING. OTHERWISE...HIGH PRESSURE CENTERED OVER NEW YORK AND PA
WILL PROVIDE US WITH DRY WEATHER AND SEASONABLE TEMPERATURES
TODAY. THERE WILL BE A GRADUAL INCREASE IN MID AND HIGH LEVEL
CLOUDS AS MOISTURE ASSOCIATED WITH WARM AIR ADVECTION OVER THE
OHIO VALLEY AND CENTRAL GREAT LAKES MOVES SLOWLY TO THE EAST.
REGIONAL RADARS SHOW AN EXPANDING AREA OF SHOWERS OVER MICHIGAN
AND CENTRAL OHIO...MOVING SLOWLY TO THE EAST. THE EASTERN EDGE OF
THIS PCPN MAY REACH FAR WESTERN NEW YORK LATE IN THE DAY...BUT THE
REST OF THE AREA SHOULD STAY DRY.
A LIGHT SOUTHERLY FLOW AHEAD OF THE MIDWEST COLD FRONT FRONT WILL
ALLOW TEMPERATURES TO WARM GENERALLY INTO THE MID AND UPPER 70S
DURING THE AFTERNOON...WITH A FEW SPOTS ACROSS THE GENESEE VALLEY
AND FINGER LAKES POSSIBLY WARMING INTO THE LOWER 80S...DEPENDING ON
HOW EXTENSIVE THE MID LEVEL CLOUDS BECOME.
CONDITIONS WILL DETERIORATE THIS EVENING AND TONIGHT AS MOISTURE
DEEPENS AHEAD OF THE APPROACHING COLD FRONT. THE LATEST GUIDANCE
STILL SHOWS STRONG FRONTOGENETIC FORCING IN THE MID LEVELS OF THE
ATMOSPHERE...WHILE A DECENT UPPER LEVEL JET LIFTS NORTH INTO WESTERN
QUEBEC. AS THESE SOURCES OF FAVORABLE LIFT INTERACT WITH THE
INCREASING MOISTURE...A PERIOD OF MODERATE RAIN IS POSSIBLE
...ESPECIALLY DURING THE SECOND HALF OF THE NIGHT. WHILE THE NAM AND
GFS QPF OUTPUTS APPEAR TO BE SUFFERING FROM CONVECTIVE FEEDBACK...A
SOLID HALF INCH OF RAIN IS POSSIBLE ACROSS PARTS OF WESTERN NEW YORK
BEFORE DAYBREAK.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THE LONGWAVE PATTERN THAT WE WILL BE IN DURING THE NEXT WEEK TO TEN
DAYS IS ONE THAT SNOW LOVERS DREAM OF HAVING DURING THE WINTER
MONTHS...BUT ALAS...THEY WILL HAVE TO BE CONTENT WITH COMFORTABLY
COOL LATE SUMMER CONDITIONS. A DEEP TROUGH WILL BE RE-ESTABLISHED
ACROSS EASTERN CANADA AND THE GREAT LAKES REGION AT THE START OF
THIS PERIOD...WITH ADDITIONAL SHORTWAVE ENERGY DIVING INTO ITS BASE
AND THE BUILDING OF A GREENLAND BLOCK INSURING THAT THE HIGH
AMPLITUDE BLOCKING PATTERN WILL BE ANCHORED IN PLACE FOR SOME TIME
TO COME. THIS GENERAL LONGWAVE PATTERN IS STRONGLY SUPPORTED BY ALL
MEDIUM RANGE ENSEMBLE PACKAGES AS WELL AS CPC FORECASTS OF
HEMISPHERIC PROCESSES...LIKE THE NAO AND PNA. MORE ON THIS IN THE
LONG RANGE DISCUSSION BELOW. NOW FOCUSING IN ON THE DETAILS...
A COLD FRONT WILL MARCH ACROSS OUR FORECAST AREA ON THURSDAY...
WITH WIDESPREAD SHOWERS AND POSSIBLY A FEW EMBEDDED THUNDERSTORMS
EXPECTED AS A RESULT. THE GUIDANCE PACKAGES HAVE BEEN DEPICTING A
PROGRESSIVELY EARLIER ONSET OF PCPN FOR THE PAST SEVERAL RUNS...AND
IT SEEMS AS IF THIS IS TIED DIRECTLY TO THE SPEED AND PLACEMENT OF
THE FAVORABLE UPPER LEVEL LIFT SUPPLIED BY A 100KT H25 JET OVER
WESTERN QUEBEC. A 3 TO 5 HOUR PERIOD OF SHOWERS WILL BE ASSOCIATED
WITH THE LIFT FOUND WITHIN THE RR ENTRANCE REGION OF THIS JET...
WITH LINGERING SHOWERS FOUND BACK IN THE VCNTY OF THE LOW LEVEL
FORCING NEAR THE FRONT. THIS WILL BOIL DOWN TO THE BULK OF THE
SHOWERS COMING DURING THE MORNING HOURS FOR THE WRN COUNTIES...AND
DURING THE MIDDAY FOR SITES EAST OF LK ONTARIO. THE SHOWERS WILL
THUS QUICKLY TAPER OFF FROM WEST TO EAST DURING THE COURSE OF THE
AFTERNOON. HAVE RAISED POPS TO 90 REGIONWIDE WITH BASIN AVERAGE QPF
RANGING FROM A QUARTER TO A HALF INCH.
BY THURSDAY EVENING...THE PLUME OF DEEP MOISTURE AHEAD OF THE
FRONT WILL BE RACING ACROSS NEW ENGLAND WHILE THE ACTUAL SFC FRONT
WILL ONLY BE SLOWLY MAKING ITS WAY ACROSS THE EASTERN LAKE ONTARIO
REGION. THIS WILL KEEP THE LIKELIHOOD FOR SOME SHOWERS OVER THE
EASTERN FINGER LAKES AND FOR SITES EAST OF LK ONTARIO...WITH JUST
SPOTTY LIGHT SHOWERS POSSIBLE UNDER A PASSING SHORTWAVE ACROSS THE
WRN COUNTIES. THE TREND WILL DEFINTIELY BE TOWARDS DRIER WEATHER
THOUGH AS LOW LEVEL RIDGING WILL BUILD EAST FROM LOWER MICHIGAN AND
THE OHIO VALLEY.
ANOTHER ISSUE TO KEEP AN EYE ON WILL BE MARGINALLY FAVORABLE
CONDITIONS FOR NUISANCE LAKE EFFECT DURING THE WEE HOURS OF
FRIDAY MORNING. H85 TEMPS ARE FORECAST TO DROP TO AROUND 10C BY
DAYBREAK...AND WITH LK SFC TEMPS IN THE VCNTY OF 22C...THAT WOULD
ONLY SUPPORT WEAK INSTABILITY. THERE WILL ALSO BE LIMITED SYNOPTIC
MOISTURE TO WORK WITH...SO WILL CONTINUE SLGT CHC POPS EAST OF LK
ERIE AND LOW CHC POPS EAST OF LK ONTARIO FOR ANY MINOR LAKE
RESPONSE.
ON FRIDAY AND FRIDAY NIGHT...A SERIES OF WEAK SHORT WAVES WILL
ROTATE THROUGH THE BASE OF THE UPPER LEVEL TROUGH THAT WILL BE
FIRMLY ESTABLISHED OVER THE GREAT LAKES. WHILE THE VAST MAJORITY OF
THIS 24 HOUR PERIOD SHOULD BE RAIN FREE...SCATTERED LIGHT SHOWERS
WILL BE POSSIBLE. THE COMBINATION OF LATE SUMMER HEATING DURING THE
MIDDAY/AFTERNOON WILL COMBINE WITH A SEASONABLY COOL AIRMASS TO
GENERATE LOW LEVEL LAPSE RATES OF 9-10 DEG C/KM...AND THIS ALONG
WITH THE FORCING FROM THE AFOREMENTIONED SHORTWAVE SHOULD BE ENOUGH
TO SUPPORT CHC POPS THROUGH THE EVENING HOURS. THE OVERNIGHT SHOULD
LARGELY BE RAIN FREE...WITH ONLY CHC POPS EAST OF LK ONTARIO FOR
SOME LAKE EFFECT. TEMPS FRIDAY WILL AVERAGE ABOUT 5 DEG F BELOW
NORMAL WITH AFTERNOON HIGHS GENERALLY IN THE MID 70S.
SATURDAY SHOULD BE A FAIRLY NICE DAY...ALBEIT IT SEASONABLY COOL AS
SFC HIGH PRESSURE CENTERED OVER THE CANADIAN PRAIRIES WILL BUILD
SOUTHEAST ACROSS ALL OF THE GREAT LAKES. THIS SHOULD ENCOURAGE
PARTIAL SUNSHINE ACROSS THE REGION WITH H85 TEMPS HOLDING MAX TEMPS
IN THE LOW TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
ALL OF THE THE MEDIUM RANGE ENSEMBLES REMAIN IN STRONG AGREEMENT
THAT THE DEEP...UPPER LEVEL TROUGH WILL HOLD IN PLACE ACROSS EASTERN
NORTH AMERICA THROUGH MUCH IF NOT ALL OF NEXT WEEK. THIS SCENARIO
WILL GUARANTEE THAT WE WILL CONTINUE TO EXPERIENCE BELOW NORMAL
TEMPERATURES...ALTHOUGH NOT ANOMALOUSLY SO AS MERCURY LEVELS WILL
GENERALLY AVERAGING 3-5 DEG F BELOW NORMAL.
IN TERMS OF PCPN...THE BULK OF THIS TIME PERIOD WILL BE RAINFREE.
BESIDES THE LOW CHC FOR NUISANCE LAKE SHOWERS SOUTHEAST OF LK
ONTARIO...CANADIAN HIGH PRESSURE BUILDING ACROSS THE LOWER GREAT
SHOULD PROVIDE THE REGION WITH DRY WEATHER SUNDAY AND MONDAY. THE
ECMWF HAS BECOME THE OUTLIER ON SUNDAY IN THAT IT SUGGESTS THAT A
VIGOROUS SHORTWAVE WILL GENERATE SOME SHOWERS...BUT THIS IS A NEW
SOLUTION AND ONE THAT IS NOT SUPPORTED BY OTHER PACKAGES.
THE POTENTIAL FOR A FAIRLY POTENT SHORTWAVE AND ASSOCIATED SFC WAVE
TO PASS THROUGH THE REGION ON TUESDAY WILL NECESSITATE THE
INTRODUCTION OF CHC POPS.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
PATCHY FOG ACROSS THE SOUTHERN TIER WILL BURN OFF BY MID MORNING.
OTHERWISE...HIGH PRESSURE CENTERED OVER NY AND PA WILL MAINTAIN VFR
CONDITIONS ACROSS THE AREA TODAY. THERE WILL BE AN INCREASE IN MID
AND HIGH LEVEL CLOUDS LATER THIS MORNING AND DURING THE AFTERNOON AS
MOISTURE DEVELOPING AHEAD OF THE MIDWEST COLD FRONT MOVES SLOWLY TO
THE EAST.
SHOWERS AND POSSIBLE THUNDERSTORMS WILL THEN SPREAD ACROSS THE AREA
THIS EVENING AND TONIGHT AS THE APPROACHING FRONT INTERACTS WITH
INCREASING MOISTURE LIFTING NORTH FROM THE OHIO VALLEY. WITH MORE
WIDESPREAD SHOWERS...CONDITIONS WILL GRADUALLY LOWER TO MVFR BEFORE
DAYBREAK AT MOST TAF SITES WEST OF KART.
OUTLOOK...
THURSDAY...VFR/MVFR WITH SHOWERS AND A FEW SCATTERED THUNDERSTORMS
PRODUCING ASSOCIATED BRIEF IFR.
FRIDAY AND SATURDAY...MAINLY VFR WITH A SMALL CHANCE OF SHOWERS.
SUNDAY...VFR.
&&
.MARINE...
A RELATIVELY WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE ACROSS THE
LOWER LAKES TODAY AND TONIGHT. AFTER A FRONT CROSSES THE LAKES ON
THURSDAY...THE WINDS WILL SWITCH TO THE SOUTHWEST AND PICK UP A
BIT...BUT CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA. MORE IMPORTANTLY...THE FRONT WILL BRING A GOOD
CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS TONIGHT AND
THURSDAY...WITH LOCAL INCREASES IN WIND AND WAVES POSSIBLE.
THE PRESSURE GRADIENT BETWEEN BETWEEN A SURFACE HIGH OVER THE MIDDLE
ATLANTIC STATES AND LOW PRESSURE PUSHING ACROSS HUDSON BAY WILL
CAUSE WESTERLY WINDS TO PICK UP A LITTLE MORE ON FRIDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TJP
NEAR TERM...TJP
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...TJP
MARINE...TJP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
904 AM CDT WED JUL 31 2013
.UPDATE...
ISSUED AT 901 AM CDT WED JUL 31 2013
LATEST VISIBLE SATELLITE IMAGERY SHOWS A SCT TO BKN CUMULUS FIELD
FROM NEAR CROSBY TO STANLEY AND INTO GARRISON...ASSOCIATED WITH A
COLD POCKET IN THE H85-H7 LAYER. THIS WILL CONTINUE TO MOVE
SOUTHEAST INTO THE JAMES RIVER VALLEY AS THE MID AND UPPER LEVEL
WINDS WINDS ARE NORTHWEST. WATER VAPOR IMAGERY SHOWS THE NEXT
SHORTWAVE NOW OVER NORTHWEST SASKATCHEWAN MOVING SOUTHEAST WITH
TIME. IT IS FORECAST TO SHIFT NEAR SASKATOON AROUND 00Z
THURSDAY...WITH SOME SPOTTY SHOWERS REACHING AS FAR SOUTH AS
BRANDON MANITOBA. AN ISOLATED SHOWER COULD CLIP THE TURTLE
MOUNTAINS EARLY THIS EVENING BUT NOT MUCH MORE THAN THAT.
MAIN ADJUSTMENT TO THE GRIDS THIS MORNING IS TO INCREASE SKY
COVER TO ACCOUNT FOR THE CUMULUS DECK...AS SOUNDINGS AND CROSS
SECTIONS SHOW WE WILL REMAIN NEARLY DRY ADIABATIC INTO THE
SHALLOW MOIST/COLDER H85-H7 LAYER. MIXING INTO DRIER AIR ALOFT
THIS AFTERNOON WILL LIMIT COVERAGE AND VERTICAL EXTENT.
UPDATE ISSUED AT 639 AM CDT WED JUL 31 2013
UPDATED THE FORECAST TO REMOVE FIRST PERIOD POPS FROM THE
SOUTHWESTERN ZONES BASED ON CURRENT RADAR OBS/TRENDS. FOR THE
SOUTHEASTERN ZONES...CHANGED PRECIPITATION WORDING TO COVERAGE
TERMINOLOGY TO BETTER REFLECT THE CURRENT CONDITIONS. THE
CONVECTIVE ACTIVITY SHOULD BE OUT OF THE SOUTHERN JAMES RIVER
BASIN IN THE NEXT FEW HOURS.
FURTHERMORE...ADDED PATCHY FOG WORDING AROUND DICKINSON GIVEN THE
LIGHT WINDS AND REDUCED VISIBILITIES HAVING BEEN REPORTED THERE FOR
ABOUT AN HOUR NOW. THINK VISIBILITIES WILL IMPROVE IN THE NEXT
HOUR OR SO WHEN VERTICAL MIXING COMMENCES.
THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED
GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT WED JUL 31 2013
MAIN FORECAST CONCERN WILL BE SHOWER AND THUNDERSTORM COVERAGE IN
THE NEAR TERM. LATEST RADAR AT 0818 UTC SHOWS THAT THE SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY GRADUALLY SHIFTING TO THE SOUTH
AND EAST. THUNDERSTORMS ARE EXPECTED TO REMAIN SUB-SEVERE...PER THE
08 UTC SPC MESOANALYSIS...AS ML AND MU CAPE ARE MINIMAL EVEN
THOUGH 50 KTS OF 0-6 KM SHEAR IS PRESENT. THE 06 UTC HRRR AND 07
UTC RAP BOTH CONTINUE THE TREND OF MOVING SHOWER AND THUNDERSTORM
ACTIVITY TO THE SOUTH AND EAST...WITH ALL ACTIVITY COMING TO AN
END ACROSS THE SOUTH CENTRAL BETWEEN 13 TO 15 UTC.
FOR TODAY AND TONIGHT...NORTHWEST FLOW WILL PREVAIL
ALLOWING FOR DRY AND QUIET WEATHER TO TAKE HOLD AS HIGH PRESSURE
MOVES OVER THE REGION. COOLER THAN TEMPERATURES ARE EXPECTED WITH
HIGHS GENERALLY IN THE 70S AND LOWS IN THE UPPER 40S TO MID 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CDT WED JUL 31 2013
THE MEDIUM RANGE MODELS ARE STILL IN FAIRLY GOOD AGREEMENT WITH
PERSISTENT NORTHWESTERLY FLOW ALOFT OVER WESTERN AND CENTRAL NORTH
DAKOTA THROUGH THE PERIOD. THIS PATTERN WILL MAINTAIN BELOW NORMAL
TEMPERATURES ACROSS THE STATE THROUGH THE FIRST WEEK IN AUGUST.
NORTHWEST FLOW IS ALSO NOTORIOUS FOR LOW PREDICTABILITY WAVES
YIELDING THE POTENTIAL FOR ISOLATED CONVECTION NEARLY EVERY DAY.
HOWEVER...THE BEST CHANCES FOR WIDESPREAD PRECIPITATION LOOK TO BE
SATURDAY THROUGH SUNDAY AS THE PACIFIC NORTHWEST UPPER LOW
PROPAGATES ALONG THE CREST OF THE RIDGE INTO THE NORTHERN PLAINS.
THUNDERSTORMS SHOULD REMAIN BELOW SEVERE LIMITS GIVEN THE WEAK
INSTABILITY PROGGED DURING THE WEEKEND. HOWEVER...WILL CONTINUE TO
MONITOR TRENDS AND ADJUST THE FORECAST AS NEEDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 639 AM CDT WED JUL 31 2013
IFR/LIFR VSBYS IN MIST/FOG OVER KDIK SHOULD IMPROVE TO VFR AFTER
14Z AS SURFACE TEMPERATURES INCREASE. OTHERWISE...VFR CONDITIONS
WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE
REMAINDER OF THE TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...LTH
LONG TERM...TM
AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
639 AM CDT WED JUL 31 2013
.UPDATE...
ISSUED AT 639 AM CDT WED JUL 31 2013
UPDATED THE FORECAST TO REMOVE FIRST PERIOD POPS FROM THE
SOUTHWESTERN ZONES BASED ON CURRENT RADAR OBS/TRENDS. FOR THE
SOUTHEASTERN ZONES...CHANGED PRECIPITATION WORDING TO COVERAGE
TERMINOLOGY TO BETTER REFLECT THE CURRENT CONDITIONS. THE
CONVECTIVE ACTIVITY SHOULD BE OUT OF THE SOUTHERN JAMES RIVER
BASIN IN THE NEXT FEW HOURS.
FURTHERMORE...ADDED PATCHY FOG WORDING AROUND DICKINSON GIVEN THE
LIGHT WINDS AND REDUCED VISIBILITIES HAVING BEEN REPORTED THERE FOR
ABOUT AN HOUR NOW. THINK VISIBILITIES WILL IMPROVE IN THE NEXT
HOUR OR SO WHEN VERTICAL MIXING COMMENCES.
THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED
GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT WED JUL 31 2013
MAIN FORECAST CONCERN WILL BE SHOWER AND THUNDERSTORM COVERAGE IN
THE NEAR TERM. LATEST RADAR AT 0818 UTC SHOWS THAT THE SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY GRADUALLY SHIFTING TO THE SOUTH
AND EAST. THUNDERSTORMS ARE EXPECTED TO REMAIN SUB-SEVERE...PER THE
08 UTC SPC MESOANALYSIS...AS ML AND MU CAPE ARE MINIMAL EVEN
THOUGH 50 KTS OF 0-6 KM SHEAR IS PRESENT. THE 06 UTC HRRR AND 07
UTC RAP BOTH CONTINUE THE TREND OF MOVING SHOWER AND THUNDERSTORM
ACTIVITY TO THE SOUTH AND EAST...WITH ALL ACTIVITY COMING TO AN
END ACROSS THE SOUTH CENTRAL BETWEEN 13 TO 15 UTC.
FOR TODAY AND TONIGHT...NORTHWEST FLOW WILL PREVAIL
ALLOWING FOR DRY AND QUIET WEATHER TO TAKE HOLD AS HIGH PRESSURE
MOVES OVER THE REGION. COOLER THAN TEMPERATURES ARE EXPECTED WITH
HIGHS GENERALLY IN THE 70S AND LOWS IN THE UPPER 40S TO MID 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CDT WED JUL 31 2013
THE MEDIUM RANGE MODELS ARE STILL IN FAIRLY GOOD AGREEMENT WITH
PERSISTENT NORTHWESTERLY FLOW ALOFT OVER WESTERN AND CENTRAL NORTH
DAKOTA THROUGH THE PERIOD. THIS PATTERN WILL MAINTAIN BELOW NORMAL
TEMPERATURES ACROSS THE STATE THROUGH THE FIRST WEEK IN AUGUST.
NORTHWEST FLOW IS ALSO NOTORIOUS FOR LOW PREDICTABILITY WAVES
YIELDING THE POTENTIAL FOR ISOLATED CONVECTION NEARLY EVERY DAY.
HOWEVER...THE BEST CHANCES FOR WIDESPREAD PRECIPITATION LOOK TO BE
SATURDAY THROUGH SUNDAY AS THE PACIFIC NORTHWEST UPPER LOW
PROPAGATES ALONG THE CREST OF THE RIDGE INTO THE NORTHERN PLAINS.
THUNDERSTORMS SHOULD REMAIN BELOW SEVERE LIMITS GIVEN THE WEAK
INSTABILITY PROGGED DURING THE WEEKEND. HOWEVER...WILL CONTINUE TO
MONITOR TRENDS AND ADJUST THE FORECAST AS NEEDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 639 AM CDT WED JUL 31 2013
IFR/LIFR VSBYS IN MIST/FOG OVER KDIK SHOULD IMPROVE TO VFR AFTER
14Z AS SURFACE TEMPERATURES INCREASE. OTHERWISE...VFR CONDITIONS
WILL PREVAIL OVER WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE
REMAINDER OF THE TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...LTH
LONG TERM...TM
AVIATION...TM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1026 AM EDT WED JUL 31 2013
.SYNOPSIS...
LOW PRESSURE CROSSES TODAY. A WEAK COLD FRONT CROSSES THURSDAY.
HIGH PRESSURE PASSES FRIDAY MORNING. A COLD FRONT CROSSES THIS
WEEKEND...FOLLOWED BY HIGH PRESSURE SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
1015 AM UPDATE...
DISTURBANCE MOVING THRU CWA ATTM WITH MAINLY SCT -SHRA AND EVEN
SOME -DZ ABOUT THE AREA. WEAKENING VORT MAX HANGING OUT ACROSS SE OH
CO WITH LOBE APPENDAGE MOVING NE INTO N WV SERVING AS MAIN FOCUS
FOR LIFT. RUC AND HRRR SEEMS TO HAVE A MUCH BETTER HANDLE ON
THINGS VS OTHER MDLS AND HAVE USED THESE AS GUIDANCE FOR THIS
UPDATE. WILL DECREASE POPS SIGNIFICANTLY WITH PASSAGE OF THIS VORT
LOBE...LINGERING ACROSS N MTNS. SE DOWNSLOPING FLOW ALSO SERVING
TO REALLY HAMPER THINGS THIS MORNING ACROSS THE LOWLANDS. HARD TO
SEE MUCH TO LATCH ON TO FOR FORCING THIS AFTN OUTSIDE OF MTNS BUT
WILL LEAVE A LOW POP IN. WOULD THINK THAT SOME OF THE LOW CLDS
WILL BREAK UP LATER THIS AFTN BUT ABUNDANT LLVL MOISTURE REMAINS
SO NOT EXPECTING MUCH IN THE WAY OF SUN.
PREVIOUS DISCUSSION FOLLOWS...
UNSETTLED WEATHER RETURNING TO THE AREA IN THE NEAR TERM. AT THE
SURFACE...HIGH PRESSURE CONTINUES TO SLIDE OFF TO THE EAST...AS A
LOW PRESSURE SYSTEM APPROACHES FROM THE WEST. SPLIT FLOW PATTERN
ALOFT OVER THE EASTERN U.S...WITH A SHORTWAVE AT 06Z PUSHING
SOUTHEAST OUT OF THE MIDWEST TOWARDS THE REGION...TO BE FOLLOWED BY
A SECONDARY SHORTWAVE WHICH WILL MOVE EAST TO NORTHEAST ACROSS THE
CWA DURING THE DAY. MODELS HAVE BACKED OFF SOMEWHAT ON QPF AMOUNTS
ACROSS THE CWA...AND INDICATE BULK OF MOISTURE/DYNAMICS SHOULD
REMAIN TO THE SOUTH AND EAST. PREVIOUS MODEL RUNS INDICATED PW
VALUES RISING TO AROUND 2 INCHES ACROSS THE CWA...BUT NOW INDICATE
VALUES OF GENERALLY AROUND 1.6 TO 1.7. WILL STILL BE HEAVIER
SHOWERS/STORMS AT TIMES TODAY...BUT THINK CWA WILL BE SPARED ANY
MAJOR WATER ISSUES...PARTICULARLY WITH 3 HR FFG ACROSS SOUTHERN AND
MOUNTAIN ZONES...WHERE HEAVIER PRECIPITATION AMOUNTS ARE
EXPECTED...ARE GENERALLY WELL OVER 2-3 INCHES IN THE 3 HOUR PERIOD.
BULK OF PRECIPITATION WILL TAPER OFF EARLY TONIGHT...BUT POST RAIN
FOG AND LOW STRATUS WILL BE THE RULE. KEPT OVERNIGHT LOW
TEMPERATURES ON THE WARM SIDE AS A RESULT. WILL CONTINUE TO MAINTAIN
A CHANCE FOR SHOWERS/STORMS ACROSS THE CWA IN THE OVERNIGHT
HOURS...AS ANOTHER UPPER SHORTWAVE TROUGH...AND SURFACE COLD FRONT
APPROACH THE CWA FROM THE WEST...WITH FRONT WINDING UP JUST TO THE
WEST OF THE CWA AT THE END OF THE PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
SHORT WAVE TROUGH EXITS FIRST THING IN THE MORNING...TAKING THE DEEP
LAYER MOISTURE AND THE LAST OF THE SIGNIFICANT RAINFALL WITH IT. A
SECOND SHORT WAVE TROUGH SETTLES INTO THE AREA LATE THU AFTER A WEAK
COLD FRONT CROSSES...LITTLE FORCING ASSOCIATED WITH EITHER AND NOT A
LOT OF MOISTURE TO WORK WITH OUTSIDE THE LOW LEVELS. WILL LIKELY
SEE A MURKY SOUGHT OF DAY WITH STRATUS AND FOG IN THE MORNING GIVING
WAY TO SOME SUNSHINE IN THE AFTERNOON ALONG WITH LOW COVERAGE POP UP
SHOWERS / THUNDERSTORMS.
HIGH PRESSURE PASSES S OF THE AREA THU NT INTO FRI..LIKELY LEADING
TO DENSE RIVER VALLEY FOG EARLY FRI MORNING. ANOTHER SHORT WAVE
TROUGH IN NEARLY ZONAL FLOW ALOFT ARRIVES FRI NT IN THE WORLD OF THE
NAM...AND LOOKS SIMILAR TO THE ONE ARRIVING IN THE NEAR TERM. OTHER
MODELS ARE SLOWER AND / OR FLATTER WITH THIS FEATURE. FOR NOW DID
EXTEND THE EXISTING SMALL CHANCE FOR PRECIPITATION SAT BACK INTO FRI
NT.
TEMPERATURES LOOKED GOOD FOR THU AND THU NT. USED ADJMET TO RAISE
HIGHS A BIT FRI AND CONSALL FOR SAME ON LOWS FRI NT.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
GENERALLY FOLLOWED WPC THINKING WITH SOME TWEAKS. HIGH PRESSURE
SHOULD PREVAIL AT THE BEGINNING OF THE PERIOD. ANOTHER COLD FRONT
WILL THEN PUSH SLOWLY SOUTHEAST WITH A CHANCE OF SHOWERS AND
STORMS SATURDAY INTO SUNDAY NIGHT. ANOTHER SYSTEM SHOULD BRING
MORE PRECIP CHANCES FOR EARLY NEXT WEEK.
TEMPERATURES SHOULD GENERALLY REMAIN SLIGHTLY BELOW NORMAL.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
12Z WEDNESDAY THRU 12Z THURSDAY...
PATCHY MVFR VALLEY FOG WILL BURN OFF AFTER 13Z.
CLOUDS THICKENING AND LOWERING IN ADVANCE OF AN APPROACHING LOW PRESSURE
SYSTEM...WHICH IS SPREADING SHOWERS THIS MORNING...AND THUNDERSTORMS
MAINLY AFTER 16Z...BACK INTO THE AREA. EXPECT LOCAL MVFR
CONDITIONS IN VICINITY OF SHOWERS/STORMS...WITH SOUTHERN WEST
VIRGINIA...EASTERN KENTUCKY...SOUTHWEST VA...AND MOUNTAINS OF WV
THE MOST FAVORED LOCATIONS FOR ACTIVITY.
AFTER 00Z...EXPECT WIDESPREAD IFR/LIFR CONDITIONS TO DEVELOP IN LOW
STRATUS AND CONTINUED SHOWER/ISOLD THUNDERSTORM ACTIVITY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND DEVELOPMENT OF MVFR CONDITIONS IN
SHOWERS AND STORMS MAY DIFFER FROM CURRENT FORECAST. DEVELOPMENT
OF LOW STRATUS AFTER 00Z MAY VARY FROM CURRENT FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H M M M M M M
HTS CONSISTENCY H H H H M M M M M M M M
BKW CONSISTENCY H H H H M M M M M M M M
EKN CONSISTENCY L H H H H H M M M M M M
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z THURSDAY...
POSSIBLE IFR IN POST-RAIN STRATUS AND FOG INTO THURSDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/SL
NEAR TERM...SL/30
SHORT TERM...TRM
LONG TERM...JSH
AVIATION...SL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
725 AM EDT WED JUL 31 2013
.SYNOPSIS...
A COLD FRONT ACROSS THE NORTHERN PLAINS WILL CONTINUE SOUTHEAST
TODAY AND DROP ACROSS THE AREA EARLY THURSDAY. WEAK HIGH PRESSURE
WILL BUILD IN ON FRIDAY AHEAD OF ANOTHER COLD FRONT THAT IS
EXPECTED ON SATURDAY. CANADIAN HIGH PRESSURE WILL BUILD IN SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...NO BIG CHANGES ALTHOUGH DID INCREASE POPS TO LIKELY
SOUTHWEST COUNTIES STARTING NOW.
PREVIOUS...HIGH PRESSURE...NOW EAST OF THE AREA WILL CONTINUE TO
LOOSE ITS GRIP ON THE AREA TODAY AS A SURFACE LOW OVER SOUTHERN
ILLINOIS MOVES THROUGH KENTUCKY BEFORE EXPANDING OVER OHIO. ALSO A
COLD FRONT OVER THE NORTHERN PLAINS WILL CONTINUE TO DROP
SOUTHEAST TOWARD THE AREA. FOLLOWING THE NAM80...THE MODEL SHOWS A
SHORT WAVE MOVING INTO THE AREA FROM THE WEST DURING THE MORNING
AND AFFECTING THE EAST HALF OF THE AREA THIS AFTERNOON. MOISTURE
WILL INCREASE ACROSS THE AREA THROUGH THE DAY AND THE HRRR SHOWS
PRECIP BREAKING OUT IN THE WEST EARLY WHICH AGREES WITH THE
CURRENT RADAR. NOT EXPECTING AN ALL DAY RAIN BUT WILL HAVE CHANCE
POPS INCREASING TO LIKELY IN THE WEST TODAY WITH POPS INCREASING
TO HIGH CHANCE EAST. WILL HAVE HIGH A DEGREE OR TWO BELOW GUIDANCE
GIVEN EXPECTED CLOUDS AND PRECIP.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT LOOKING FOR PRECIP TO EXPAND ACROSS THE AREA AS COLD FRONT
APPROACHES FROM THE NORTHWEST AND MORE JET ENERGY DROP ACROSS THE
AREA. WILL HAVE CATEGORICAL POPS EAST AND LIKELY POPS WEST. WEAK
HIGH PRESSURE BUILDS IN FRIDAY SO WILL TAPER POPS WEST THROUGH THE
NIGHT INTO THURSDAY. WILL ALSO TAPER EAST BUT WILL HOLD ONTO A LOW
CHANCE POP TO COVER ANY LINGERING MOISTURE WITH THE AFTERNOON
INSTABILITY THAT DEVELOPS UNDER THE UPPER TROF. A BIT CONCERNED
ABOUT WESTERN COUNTIES FOR THE SAME REASON BUT FOR NOW WILL KEEP
DRY. FRIDAY AFTERNOON WILL BRING BACK CHANCE POPS AS SECOND COLD
FRONT APPROACHES FROM THE NORTHWEST. BOTH THE NAM AND GFS SHOW
SHORT WAVES DROPPING ACROSS THE AREA WITH THE MEAN TROUGH
REMAINING ACROSS THE GREAT LAKES AND OHIO VALLEY. CHANCE POPS WILL
CONTINUE FRIDAY NIGHT AND SATURDAY AS THE FRONT DROPS THROUGH. DRY
AIR AND BUILDING HIGH PRESSURE EXPECTED SATURDAY NIGHT. HIGHS
RATHER UNREMARKABLE FOR THIS TIME OF YEAR WITH MOST LOCATIONS ON
MOST DAYS LIKELY NOT GETTING OUT OF THE 70S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
NOT MUCH CHANGE GOING INTO NEXT WEEK. STILL MAINTAIN AN EASTERN U.S.
TROUGH AND THEREFORE TEMPERATURES THAT WILL BE RUNNING SLIGHTLY
BELOW NORMAL. THE UPPER TROUGH AXIS WILL BE EAST OF THE AREA SUNDAY
WITH SURFACE HIGH PRESSURE BUILDING IN ACROSS THE GREAT LAKES AND
OHIO VALLEY. NEXT MINOR UPPER WAVE RE-ENFORCING THE LONGWAVE
TROUGH...MAY BRING IN A FEW SHOWERS MONDAY NIGHT...GIVE OR TAKE A
LITTLE DUE TO TIMING IT THIS FAR OUT.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
SLOW MOVING AND WEAK SYSTEM TO CROSS THE AREA BETWEEN 12Z WED AND
12Z THU. ONE BATCH OF SHOWERS MOVING EAST ALONG AND SOUTH OF A
LINE FROM FDY/MFD/CAK. SOME AREAS OF MVFR VSBY WITHIN THE RAIN.
ANY SHOWERS AFTER THIS WAVE WILL LIKELY BE SPOTTY AND HIT OR MISS
SINCE THE NEXT FEATURE TO KICK OFF SHOWERS AND POSSIBLY A RUMBLE
OF THUNDER WILL BE MOVING IN FOR THIS EVENING/TONIGHT.
PREDOMINATELY VFR UP UNTIL THIS EVENING. LIGHT/VARIABLE TO LIGHT
SOUTH WINDS TODAY. ONLY HAVE MEDIUM CONFIDENCE IN TIMING OF
PRECIP FOR TONIGHT BUT COVERAGE LOOKS LIKELY. NON-VFR CONDITIONS
IN THE SHRA/TS AND THEN LOW END MVFR OR IFR CIGS A GOOD BET WITH
AND AFTER THE COLD FRONT FOR A TIME. IMPROVEMENT THURSDAY MORNING.
.OUTLOOK...AREAS OF NON-VFR EARLY THURSDAY AND POSSIBLY AGAIN
THURSDAY AFTERNOON IN SHRA.
&&
.MARINE...
IT WILL REMAIN RELATIVELY QUIET ON THE LAKE FOR THE NEXT FEW DAYS.
ONLY FEATURES OF NOTE ARE A WEAK COLD FRONT CROSSING THE LAKE
TONIGHT. THIS AFTERNOON WINDS WILL BE LIGHT/VARIABLE...BECOMING
LIGHT SOUTH AHEAD OF THE FRONT. A SHIFT TO THE WEST CAN BE EXPECTED
AFTER THE FRONT...BUT SPEEDS STILL LIGHT. A SECONDARY TROUGH CROSSES
THE LAKE THURSDAY NIGHT AND HIGH PRESSURE THEN BUILDS ACROSS THE
OHIO VALLEY FOR FRIDAY. ANOTHER WEAK COLD FRONT SLIPS ACROSS THE
LAKE SATURDAY. UNCERTAIN AS TO IF CONDITIONS WILL GET CHOPPY ENOUGH
FOR ANY SMALL CRAFT ADV CONDITIONS. GRADIENT SEEMS FAIRLY WEAK. THE
CHOPPIER CONDITIONS MAY ACTUALLY ARRIVE BRIEFLY SUNDAY AS THE HIGH
BUILDS IN. OBVIOUSLY THERE IS LOW CONFIDENCE YET.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
637 AM EDT WED JUL 31 2013
.SYNOPSIS...
A COLD FRONT ACROSS THE NORTHERN PLAINS WILL CONTINUE SOUTHEAST
TODAY AND DROP ACROSS THE AREA EARLY THURSDAY. WEAK HIGH PRESSURE
WILL BUILD IN ON FRIDAY AHEAD OF ANOTHER COLD FRONT THAT IS
EXPECTED ON SATURDAY. CANADIAN HIGH PRESSURE WILL BUILD IN SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...NO BIG CHANGES ALTHOUGH DID INCREASE POPS TO LIKELY
SOUTHWEST COUNTIES STARTING NOW.
PREVIOUS...HIGH PRESSURE...NOW EAST OF THE AREA WILL CONTINUE TO
LOOSE ITS GRIP ON THE AREA TODAY AS A SURFACE LOW OVER SOUTHERN
ILLINOIS MOVES THROUGH KENTUCKY BEFORE EXPANDING OVER OHIO. ALSO A
COLD FRONT OVER THE NORTHERN PLAINS WILL CONTINUE TO DROP
SOUTHEAST TOWARD THE AREA. FOLLOWING THE NAM80...THE MODEL SHOWS A
SHORT WAVE MOVING INTO THE AREA FROM THE WEST DURING THE MORNING
AND AFFECTING THE EAST HALF OF THE AREA THIS AFTERNOON. MOISTURE
WILL INCREASE ACROSS THE AREA THROUGH THE DAY AND THE HRRR SHOWS
PRECIP BREAKING OUT IN THE WEST EARLY WHICH AGREES WITH THE
CURRENT RADAR. NOT EXPECTING AN ALL DAY RAIN BUT WILL HAVE CHANCE
POPS INCREASING TO LIKELY IN THE WEST TODAY WITH POPS INCREASING
TO HIGH CHANCE EAST. WILL HAVE HIGH A DEGREE OR TWO BELOW GUIDANCE
GIVEN EXPECTED CLOUDS AND PRECIP.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT LOOKING FOR PRECIP TO EXPAND ACROSS THE AREA AS COLD FRONT
APPROACHES FROM THE NORTHWEST AND MORE JET ENERGY DROP ACROSS THE
AREA. WILL HAVE CATEGORICAL POPS EAST AND LIKELY POPS WEST. WEAK
HIGH PRESSURE BUILDS IN FRIDAY SO WILL TAPER POPS WEST THROUGH THE
NIGHT INTO THURSDAY. WILL ALSO TAPER EAST BUT WILL HOLD ONTO A LOW
CHANCE POP TO COVER ANY LINGERING MOISTURE WITH THE AFTERNOON
INSTABILITY THAT DEVELOPS UNDER THE UPPER TROF. A BIT CONCERNED
ABOUT WESTERN COUNTIES FOR THE SAME REASON BUT FOR NOW WILL KEEP
DRY. FRIDAY AFTERNOON WILL BRING BACK CHANCE POPS AS SECOND COLD
FRONT APPROACHES FROM THE NORTHWEST. BOTH THE NAM AND GFS SHOW
SHORT WAVES DROPPING ACROSS THE AREA WITH THE MEAN TROUGH
REMAINING ACROSS THE GREAT LAKES AND OHIO VALLEY. CHANCE POPS WILL
CONTINUE FRIDAY NIGHT AND SATURDAY AS THE FRONT DROPS THROUGH. DRY
AIR AND BUILDING HIGH PRESSURE EXPECTED SATURDAY NIGHT. HIGHS
RATHER UNREMARKABLE FOR THIS TIME OF YEAR WITH MOST LOCATIONS ON
MOST DAYS LIKELY NOT GETTING OUT OF THE 70S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
NOT MUCH CHANGE GOING INTO NEXT WEEK. STILL MAINTAIN AN EASTERN U.S.
TROUGH AND THEREFORE TEMPERATURES THAT WILL BE RUNNING SLIGHTLY
BELOW NORMAL. THE UPPER TROUGH AXIS WILL BE EAST OF THE AREA SUNDAY
WITH SURFACE HIGH PRESSURE BUILDING IN ACROSS THE GREAT LAKES AND
OHIO VALLEY. NEXT MINOR UPPER WAVE RE-ENFORCING THE LONGWAVE
TROUGH...MAY BRING IN A FEW SHOWERS MONDAY NIGHT...GIVE OR TAKE A
LITTLE DUE TO TIMING IT THIS FAR OUT.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SLOW MOVING AND WEAK SYSTEM TO CROSS THE AREA BETWEEN 12Z WED AND
12Z THU. FOR THE REST OF THE OVERNIGHT HOURS...VFR. ANY LIGHT SHRA
DURING THE DAYLIGHT HOURS TODAY WILL BE SPOTTY AND HIT OR MISS.
CEILINGS WILL EVER SO SLOWLY LOWER...STAYING VFR THROUGH THE
AFTERNOON. THE BEST CHANCES OF SHRA AND POSSIBLY A RUMBLE OF THUNDER
ARRIVE THIS EVENING...ALONG WITH THE CHANCES OF NON-VFR WEATHER. THE
BEST DEFINED SURFACE FEATURE...A WEAK COLD FRONT WILL BE NEARING
TOL/FDY BY 06Z THU. MAY HAVE SOME NON-VFR CEILINGS BEHIND THIS
FRONT. WINDS WILL BE LIGHT/VARIABLE TO LIGHT SOUTH TODAY AND INTO
TONIGHT.
.OUTLOOK...AREAS OF NON-VFR POSSIBLE WEDNESDAY NIGHT AND THURSDAY.
&&
.MARINE...
IT WILL REMAIN RELATIVELY QUIET ON THE LAKE FOR THE NEXT FEW DAYS.
ONLY FEATURES OF NOTE ARE A WEAK COLD FRONT CROSSING THE LAKE
TONIGHT. THIS AFTERNOON WINDS WILL BE LIGHT/VARIABLE...BECOMING
LIGHT SOUTH AHEAD OF THE FRONT. A SHIFT TO THE WEST CAN BE EXPECTED
AFTER THE FRONT...BUT SPEEDS STILL LIGHT. A SECONDARY TROUGH CROSSES
THE LAKE THURSDAY NIGHT AND HIGH PRESSURE THEN BUILDS ACROSS THE
OHIO VALLEY FOR FRIDAY. ANOTHER WEAK COLD FRONT SLIPS ACROSS THE
LAKE SATURDAY. UNCERTAIN AS TO IF CONDITIONS WILL GET CHOPPY ENOUGH
FOR ANY SMALL CRAFT ADV CONDITIONS. GRADIENT SEEMS FAIRLY WEAK. THE
CHOPPIER CONDITIONS MAY ACTUALLY ARRIVE BRIEFLY SUNDAY AS THE HIGH
BUILDS IN. OBVIOUSLY THERE IS LOW CONFIDENCE YET.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
ISSUED BY NATIONAL WEATHER SERVICE RALEIGH NC
1037 AM EDT WED JUL 31 2013
.SYNOPSIS...
AN UPPER-LEVEL DISTURBANCE WILL TRACK FROM THE TENNESSEE VALLEY
TOWARD THE SOUTHEAST STATES THROUGH THURSDAY BRINGING RAIN TO THE
REGION TODAY ALONG WITH UNSEASONABLY COOL TEMPERATURES. A COLD
FRONT WILL MOVE THROUGH THE AREA THURSDAY...RESULTING IN
DECREASING CLOUDS AND MORE SCATTERED SHOWER ACTIVITY. WEAK HIGH
PRESSURE WILL THEN DOMINATE THROUGH SATURDAY WHEN THE NEXT COLD
FRONT ARRIVES FROM THE OHIO VALLEY. WARMER TEMPERATURES ARE
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND WITH SCATTERED
MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1037 AM EDT WEDNESDAY...
HAVE MADE A FEW TWEAKS TO POPS FOR THE REST OF THIS MORNING BASED
ON CURRENT RADAR TRENDS...OTHERWISE CURRENT FORECAST ON-TRACK.
WHILE THE MORNING ANALYSIS SHOWS THAT THERE IS STILL PLENTY OF
SHORT WAVE ENERGY UPSTREAM...PARTICULARLY OVER THE SOUTHERN
APPALACHIANS...NOTED THAT THE LATEST HRRR RUN SHOWS THE BEST
COVERAGE OF NEW PRECIP DEVELOPMENT OCCURRING ACROSS THE SOUTH-
CENTRAL AND EASTERN ZONES LATER THIS AFTERNOON.
PREV DISC AS OF 430 AM EDT WEDNESDAY...
FOCUS FOR THE NEAR TERM WILL BE ONUPPER DISTURBANCE TRACKING FROM
THE TENNESSEE VALLEY SE TOWARD GA/SC THROUGH EARLY THU. AS
EXPECTED FOR THE PAST SEVERAL DAYS...THIS WILL BE MAINLY A -RA
EVENT FOR OUR CWA...WITH VERY LIMITED HEATING AND AN IN SITU WEDGE
DEVELOPING FROM EXTENSIVE CLOUD COVER AND -RA FALLING INTO THE
RELATIVELY DRY AIR FOR THE END OF JULY...ONLY EXPECTING -RA WITH
ISOLD MODERATE RA THROUGH 12Z THU. WHILE THERE ARE SOME
DIFFERENCES BETWEEN THE GFS/ECMWF/CMC WITH A COOLER/LESS QPF
SOLUTION AS COMPARED TO THE MUCH WETTER/STORMIER NAM...HAVE LEANED
HEAVILY TOWARD THE GFS/ECMWF/CMC SUITE WITH NEAR ZERO INSTABILITY
INDICATED TODAY PER EARLIER THINKING. CONSEQUENTLY...HAVE REMOVED
ALL MENTION OF TSRA WITH THIS PACKAGE THROUGH 12Z THU. OVERALL
RAINFALL FOR MOST OF THE CWA SHOULD BE IN THE 0.5 TO 1.0 INCH
RANGE AT BEST WITH -RA DOMINATING MOST OF THE TIME. NOTE...LATEST
1-2 DAY WPC QPF MOSTLY ONE INCH OR LESS. THUS...NO CONCERNS FOR OR
NEED FOR A FLASH FLOOD WATCH WITHIN THIS PERIOD.
HAVE CONTINUED THE TREND OF ADVERTISING BELOW TO MUCH BELOW NORMAL
TEMPERATURES TODAY PER REASONING NOTED ABOVE OF IN SITU WEDGE
FROM CLOUDS AND RAIN BEGINNING EARLY...WITH DEWPOINTS STILL IN THE
MID 50S TO LOWER 60S...RATHER LOW FOR LATE JULY. DIURNAL RANGE
WILL BE LIMITED AND COOLING OVERNIGHT INTO THU MORNING WILL ALSO
BE LIMITED...WITH MOST AREAS AT LEAST 5 DEG WARMER THAN THIS
MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 232 PM EDT TUESDAY...
ANOTHER WEAK UPPER WAVE REINFORCING TROUGH WITH ASSOCIATE SURFACE
FRONT TO PUSH THROUGH ON THURSDAY. SOME SIGNS THIS WILL CONTINUE
TO TAP SOME GULF MOISTURE BUT NOTHING LIKE WHAT WE SAW THIS PAST
WEEKEND AND LOOKS TO BE A PROGRESSIVE SYSTEM SO PREFER FASTER
SOLUTIONS...WHICH ARE ECMWF AND NAM VS. SLOWER GFS. PRECIP COULD
MOVE EAST OF FCST AREA BY 21Z BUT HAVE LEFT SOME LOW CHC POPS IN
THROUGH 03Z DUE TO SOME UNCERTAINTY...BUT FEELING IS THIS IS
LIKELY TO MOVE THROUGH FASTER VS. SLOWER. WE SHOULD LOSE ANY WEAK
WEDGE AHEAD OF THE FRONT BY MORNING...SO MODEST INSTABILITY
ESPECIALLY OUT EAST AHEAD OF FRONT FROM MIDDAY ONWARD...SO THUNDER
IN GRIDS AFTER 15Z AND HIGHEST QPF AHEAD OF FRONT IN FAR EAST BY
AFTERNOON. NOT READY TO GO CATEGORICAL...MAINLY DUE TO THE
LINGERING UNCERTAINTY IN TIMING AND WHERE ALONG FRONT THERE MIGHT
BE MORE CONTINUOUS COVERAGE VS. SCATTERED SHOWERS/STORMS. AT THIS
POINT SEVERE CHANCES LOOK MINIMAL GIVEN MODERATE INSTABILITY AND
FAIRLY WEAK SHEAR. ALSO DOES NOT APPEAR CONVECTION ORGANIZED
ENOUGH FOR MUCH OF A FLASH FLOOD THREAT...NOR IS THERE ANY UPSLOPE
COMPONENT ALONG BLUE RIDGE AND AREAS OF CONVECTION SHOULD BE
MOVING QUICKLY WITH FRONTAL BOUNDARY. TEMPERATURES IN MOST PLACES
SHOULD BE ON COOL SIDE OF GUIDANCE...BUT WILL HAVE TO CONSIDER
POTENTIAL FOR DECENT AMOUNT OF SUN IN THE WEST IF FRONT MOVES
FASTER...EXCEPT FOR FAR WESTERN SLOPES WHERE CLOUDS AND A FEW
SHOWERS COULD LINGER. SO SOME SPOTS IN WESTERN VALLEYS MAY WARM TO
AS MUCH OR HIGHER THAN PIEDMONT...DEPENDING ON TIMING OF
FRONT...LINGERING PRECIP EAST IN AFTERNOON...AND SUNSHINE IN WEST.
SOMEWHAT DRIER AIR BUT NOT NECESSARILY MUCH COOLER AIRMASS BEHIND
FRONT FOR THURS NIGHT INTO FRIDAY. DOWNSLOPE AND MORE SUN SHOULD
CONTRIBUTE TO WARMER TEMPS...ESPECIALLY OUT EAST BUT PROBABLY
EVERYWHERE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 420 AM EDT WEDNESDAY...
ANOTHER FRONT TO SLIDE DOWN FROM NORTH BY END OF WEEKEND WITH WAVE
POSSIBLY BRINGING SHOWERS IN AHEAD OF IT AS EARLY AS SATURDAY
MORNING. TRICKY TO KNOW THIS FAR OUT JUST HOW MUCH THIS FRONT WILL
SAG SOUTH ACROSS FCST AREA...AND WHETHER BY LATE SUNDAY IT WILL
ACTUALLY DROP SOUTH OF THE AREA OR STALL ACROSS US...BUT LATEST
TRENDS SUGGEST IT MAY TRY TO MAKE IT THROUGH THUS MADE SOME
ADJUSTMENTS TO POPS BASED ON THIS. TEMPS LIKELY AT OR JUST BELOW
NORMAL THROUGH WEEKEND AND INTO EARLY NEXT WEEK WITH THE EFFECTS OF
THIS FRONTAL BOUNDARY PASSING THROUGH...AND THEN THE POSSIBILITY OF
LIFTING BACK ACROSS US AS A WARM FRONT BRINGING PRECIP CHANCES
AROUND WITH ONLY A SHORT BREAK...IF ANY...LATE SUNDAY INTO MONDAY.
MUCH UNCERTAINTY AT THIS TIME HOWEVER.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 AM EDT WEDNESDAY...
-RA CONTINUED TO SPREAD ACROSS THE CWA FROM W-E WITH MID/HIGH VFR
CIGS. HAVE YET TO SEE ANY CLOUDS MUCH BELOW 050 ANYWHERE...MOST
AOA 080. VSBYS MOSTLY VFR WITH PCPN FALLING FROM HIGH BASED CIGS
WITH SPOTTY GROUND FOG LWB/LYH/BCB. EXPECT WIDESPREAD -RA TO
CONTINUE TO OVERSPREAD THE AREA FROM W-E INTO MID- MORNING WITH
MOSTLY VFR TO HIGH END MVFR CIGS...GENERALLY AOA035. AS THE
INSITU WEDGE EVOLVES THROUGH THE DAY...EXPECT CIGS TO LOWER TOWARD
MVFR TOWARD EVENING AND ESPECIALLY TOWARD 06Z. MODELS HINT THAT
BULK OF PCPN MAY PASS THROUGH THE CWA IN THE 12Z-20Z TIME
FRAME...MOVING EAST OF THE CWA AFT 20Z. AM CONCERNED THAT THERE
MAY BE -DZ OVERNIGHT IN THE LYH/ROA/BCB AREA...WITH ATTENDING
LOWER VSBYS AS A RESULT. OCCASIONAL MVFR VSBYS CAN BE EXPECTED
THROUGH THE DAYTIME IN -RA BR. WINDS FAVORING A SSE-SSW DIRECTION
WITH SPEEDS MOSTLY AOB 5KTS. HAVE REMOVED ALL MENTION OF TSRA AS
GFS AT LEAST SHOWS NEAR ZERO INSTABILITY TODAY AND WITH AN INSITU
WEDGE AND EXTENSIVE CLOUD COVER/LIGHT PCPN...WOULD NOT EXPECT
ENOUGH INSTABILITY TO BE REALIZED FOR TSRA. IF THERE WERE...ONLY
DAN WOULD SEEM TO HAVE THE POTENTIAL FOR SUCH.
MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH 00Z...THEN MEDIUM
CONFIDENCE.
MEDIUM CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD THROUGH TAF VALID PERIOD.
MEDIUM CONFIDENCE IN WIND DIR THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN LITTLE TO NO THUNDER AT TAF SITES
THROUGH TAF VALID PERIOD.
EXTENDED AVIATION DISCUSSION...
COLD FRONT ARRIVES THURSDAY WITH POTENTIAL FOR DEEPER CONVECTION
ESPCLY EAST OF THE BLUE RIDGE THURSDAY AFTERNOON. THIS FRONT WILL
PUSH SOUTHEAST OF US THURSDAY NIGHT WITH VFR RETURNING...OUTSIDE
FOG IN THE MORNINGS AT TYPICAL SITES KLWB/KBCB...AND MAYBE
KLYH/KDAN GIVEN WET GROUND.
ANOTHER FRONT ARRIVES SOMETIME THIS WEEKEND AND COULD BRING
SHOWERS AND STORMS...WITH SUB-VFR AT TIMES.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...NP/RAB
SHORT TERM...SK
LONG TERM...RCS/SK
AVIATION...JH/RAB
AREA FORECAST DISCUSSION
NWS FLAGSTAFF AZ
330 PM MST WED JUL 31 2013
.SYNOPSIS...MOISTURE AND INSTABILITY HAS INCREASED OVER NORTHERN
ARIZONA WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TODAY.
THUNDERSTORM COVERAGE SHOULD INCREASE FURTHER ON THURSDAY AND FRIDAY.
&&
.DISCUSSION...SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPED FROM
NEAR DESERT VIEW AT THE GRAND CANYON...MOGOLLON RIM...TO THE WHITE
MOUNTAINS TODAY. THE STORMS ARE MOVING NORTHWARD INTO THE LCR THIS
AFTERNOON. THIS ACTIVITY IS EXPECTED TO CONTINUE INTO THIS EVENING.
VISIBLE SATELLITE SHOWED SEVERAL UPPER DISTURBANCES OVER NORTHERN
MEXICO THIS MORNING. THESE DISTURBANCES ARE MORNING NORTHWARD AND
MAY WELL CONTINUE THUNDERSTORM ACTIVITY WELL INTO THE NIGHT OVER
NORTHERN ARIZONA. THE 17Z RUN OF THE HRRR SHOWED RAIN SHOWERS
RE-DEVELOPING OVER THE RIM COUNTRY LATE THIS EVENING. HAVE KEPT
CHANCE POPS GOING THROUGH THE NIGHT FOR THE HIGHER TERRAIN OVER MUCH
OF NORTHERN ARIZONA.
HIGH PRESSURE WILL REMAIN EAST OF ARIZONA FOR THE NEXT WEEK. ARIZONA
WILL BE ON THE WESTERN EDGE OF THE HIGH WITH A SOUTH TO SOUTHWEST
FLOW OVER THE STATE. THE GFS AND EC ARE AT ODDS ON HOW MUCH MOISTURE
WILL MOVE OVER THE STATE AND IF/WHEN SIGNIFICANT DRYING WILL HAPPEN.
FORECAST LEANS MORE TOWARD THE EC GIVEN HOW IT HAS HANDLED THE
WETTER PATTERN SO FAR THIS SUMMER.
SHOWER AND THUNDERSTORM COVERAGE SHOULD INCREASE EACH DAY ACROSS
THE AREA THROUGH FRIDAY AND THEN REMAIN FAIRLY CONSTANT THROUGH THE
WEEKEND.
&&
.AVIATION...FOR THE 00Z PACKAGE...MONSOON MOISTURE IS ON THE
INCREASE. ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE UNTIL
04Z...DIMINISHING THE REMAINDER OF THE NIGHT. WIND GUSTS UP TO 40
KTS NEAR STORMS. THUNDERSTORM WILL DEVELOP AGAIN ON THURSDAY AFTER
18Z. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...MONSOON MOISTURE WILL PUSH BACK ACROSS NORTHERN
ARIZONA WITH AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS ON
THURSDAY AND FRIDAY.
SATURDAY THROUGH MONDAY...THE CHANCE FOR SHOWERS AND THUNDERSTORMS
WILL CONTINUE OVER NORTHERN ARIZONA.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC.........MAS
AVIATION.......MCCOLLUM
FIRE WEATHER...MCCOLLUM
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
205 PM EDT WED JUL 31 2013
.PREV DISCUSSION... /ISSUED 431 AM EDT WED JUL 31 2013/
SHORT TERM /TODAY THROUGH THURSDAY/...
RAIN ALREADY RETURNING TO THE AREA TODAY AS PERTURBATIONS MOVE
THROUGH THE UPPER LEVEL FLOW. MEDIUM RANGE AND HI RES MODELS ARE
IN AGREEMENT THAT THE CWA WILL SEE CONVECTION TODAY...HOWEVER
CONSIDERABLE DISAGREEMENT IN TERMS OF TIMING. WRF NMM SEEMS TO
HAVE A SURGE IN CONVECTION DURING THE MORNING THAN A LULL DURING
THE AFTERNOON. LOCAL WRF TENDS TO WEAKEN CONVECTION THIS
MORNING...DEVELOP ACROSS CENTRAL GEORGIA THIS AFTERNOON AND THEN
ACROSS THE NORTH DURING THE LATE AFTERNOON. HRRR CONTINUES TO
SHIFT THE CURRENT CONVECTION TO THE EAST AND THEN DEVELOP
CONVECTION ACROSS THE ENTIRE CWA AS THE AFTERNOON APPROACHES.
GIVEN ALL OF THIS AND MEDIUM RANGE MODELS...GOOD CONFIDENCE OF
HIGH POPS FOR TODAY...HOWEVER LOW CONFIDENCE IN TERMS OF TIMING.
FORECAST IS MOST CLOSELY IN LINE WITH THE HRRR.
FOR THE STORMS CURRENTLY ONGOING...MAIN CONCERN IS GUSTY WINDS. GFS
CAPE FORECAST LOOKS MORE REASONABLE TODAY...RATHER THAN LAST NIGHT
WHERE IT WAS GAPPING THE CWA WITH INSTABILITY. FORECAST CAPE VALUES
ARE AROUND 1500-2000 J/KG FOR THE AFTERNOON. STILL EXPECTING BETWEEN
20 AND 30KTS OF DEEP LAYER SHEAR TODAY AND BETWEEN THIS AND THE
INSTABILITY VALUES...COULD SEE ISOLATED SEVERE STORMS. MAIN THREAT
WILL BE DAMAGING WINDS. ALTHOUGH THE CWA HAS HAD A FEW DAYS WITHOUT
RAIN...ALLOWING US TO BE ABLE TO HANDLE MORE IN TERMS OF
RAINFALL...WILL STILL HAVE TO MONITOR RAINFALL AMOUNTS CLOSELY.
AROUND ONE TO ONE AND A HALF INCHES OF RAIN IS EXPECTED THROUGH
THURSDAY...WITH LOCALIZED HIGHER AMOUNTS POSSIBLE. 1HR FFG VALUES
ARE AROUND 2.5 TO 3.5 INCHES SO WE SHOULD BE ABLE TO HANDLE THESE
AMOUNTS...BUT THERE IS THE POTENTIAL FOR LOCALIZED FLOODING WITH
HIGHER RAINFALL VALUES.
SFC FRONT MOVES THROUGH CWA ON THURSDAY. CONVECTION SHOULD DECREASE
BY THURSDAY MORNING...BUT THEN INCREASE AGAIN ON THURSDAY ALONG AND
SOUTH OF THIS FRONT.
11
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AT THE BEGINNING OF THE PERIOD A WEAK FRONTAL BOUNDARY WILL BE
MOVING INTO CENTRAL GEORGIA. CONVECTION ASSOCIATED WITH THIS
BOUNDARY MAY BE ONGOING. EXPECT THIS CONVECTION TO BE ON A GENERAL
WEAKENING TREND THROUGH THE EVENING. AT THIS POINT FRIDAY LOOKS TO
BE THE BEST DAY FOR NO POPS ACROSS THE REGION AS WE WAIT FOR
NORTHWEST FLOW TO BRING US ANOTHER IMPULSE AND RAIN TO THE AREA.
MOISTURE ASSOCIATED WITH DORIAN SHOULD HELP IN INCREASE PWATS AND
RAIN CHANCES THIS WEEKEND AND INTO NEXT WEEK. THE MODELS SUGGEST
THAT WE KEEP NORTHWEST FLOW THROUGH AT LEAST MID NEXT WEEK...WHEN
THEY TRY TO BUILD A RIDGE INTO THE SOUTHERN UNITED STATES. MAY
CONCERN IN THE EXTENDED COULD BE RAINFALL ASSOCIATED WITH THE
SHOWERS AND THUNDERSTORMS THIS WEEKEND AND INTO EARLY NEXT WEEK.
THIS WILL NEED TO BE MONITORED CLOSELY FOR POSSIBLE FLOODING AS WE
APPROACH THIS WEEKEND.
ARG
&&
.AVIATION...
18Z UPDATE...
WITH WIDESPREAD PRECIPITATION ONGOING ACROSS THE REGION WE ALREADY
HAVE A WIDE MIXTURE OF IFR TO VFR CONDITIONS. THIS SHOULD CONTINUE
WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE
FORECAST AREA THROUGH AT LEAST 06Z. WIDESPREAD IFR CONDITIONS ARE
EXPECTED TO DEVELOP BY 06-10Z...LASTING THROUGH 12Z AND IMPROVING TO
MVFR ACROSS MOST OF THE AREA BY 14Z. WINDS HAVE BEEN SOMEWHAT
VARIABLE BUT SHOULD BEGIN TRENDING TOWARD SOUTHWESTERLY AND
EVENTUALLY WESTERLY OVERNIGHT.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 69 88 68 / 70 60 30 20
ATLANTA 84 71 87 70 / 80 60 30 10
BLAIRSVILLE 77 66 83 62 / 90 60 20 10
CARTERSVILLE 85 69 88 66 / 80 60 20 10
COLUMBUS 88 72 91 72 / 70 70 50 30
GAINESVILLE 82 70 86 68 / 70 60 30 10
MACON 87 71 90 70 / 90 50 50 30
ROME 84 70 89 66 / 90 70 20 10
PEACHTREE CITY 84 70 87 66 / 90 50 30 20
VIDALIA 88 73 88 72 / 70 80 60 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....ARG
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1244 PM CDT WED JUL 31 2013
.UPDATE...
ISSUED AT 1234 PM CDT WED JUL 31 2013
THE CLEARING TREND IS SLOW BUT CONTINUES. WHERE THE CLOUDS HAVE
CLEARED DIURNAL CU HAS DEVELOPED. BASED ON OVERALL TEMPERATURE
TRENDS THE MAX TEMPERATURES HAVE BEEN LOWERED BY A DEGREE.
THE POSSIBILITY OF DIURNAL CONVECTION IS BECOMING DOUBTFUL. THE
RAP TRENDS CONTINUE TO SHOW BOTH THE THERMAL AND CONVECTIVE
TEMPERATURES RISING TO OR ABOVE THE MAX TEMPERATURES FOR THIS
AFTERNOON. THE CU THAT HAS DEVELOPED HAS SHOWN NO UPSCALE GROWTH
SUGGESTING CONVECTION IS NOT IMMINENT.
POPS FOR THIS AFTERNOON HAVE BEEN CUT BACK A BIT FURTHER BUT MAY
STILL BE TOO HIGH IN AREAL COVERAGE AND AMOUNTS. IF CONVECTION
DOES OCCUR...IT WOULD BE DURING PEAK HEATING AND THEN MAY ONLY BE
ISOLATED SHOWERS. ..08..
UPDATE ISSUED AT 959 AM CDT WED JUL 31 2013
SATELLITE TRENDS THIS MORNING SHOW THE CLOUDS ARE
THINNING/CLEARING. THIS THINNING/CLEARING WILL CONTINUE DURING THE
LATE MORNING AND EARLY AFTERNOON HOURS.
THERE ARE QUESTIONS REGARDING THE POTENTIAL FOR DIURNAL CONVECTION
THIS AFTERNOON. THERE IS NO REAL COHERENT BOUNDARY AND THE FORCING
IS QUITE WEAK. IMMEDIATE TRENDS FROM THE RAP SHOW DOWNWARD MOTION
CONTINUING INTO LATE MORNING BEFORE SOME LIFT DEVELOPS AHEAD OF
THE NEXT SHORTWAVE IN THE AFTERNOON. FCST SOUNDINGS SHOW
CONVECTIVE TEMPERATURES CLIMBING INTO THE UPPER 70S WHICH IS RIGHT
AROUND THE MAX TEMPERATURES FOR THE DAY.
SO...WILL CONTINUE THE POSSIBILITY OF ISOLATED
SHOWERS/THUNDERSTORMS ACROSS MAINLY THE NORTHERN CWFA DURING THE
AFTERNOON FOR NOW. THE POSSIBILITY DOES EXIST THAT THE PRECIP
POTENTIAL MAY GET PULLED DEPENDING UPON HOW THINGS EVOLVE DURING
THE AFTERNOON. ..08..
&&
.SYNOPSIS...
ISSUED AT 305 AM CDT WED JUL 31 2013
ANALYSIS AT 07Z (2 AM CDT) DEPICTS AREA UNDER LOW CLOUDS AND FOG AS
REMNANTS OF UPPER DISTURBANCE FROM YESTERDAY MOVES EAST. SURFACE
ANALYSIS PRESSURE RISE AND FALL PATTERN SUPPORTS UPPER AIR AND MOST
SOLUTIONS OF SLIGHTLY DRIER AIR AND SUBSIDENCE TO ARRIVE NEXT
SEVERAL HOURS FROM THE NORTHWEST. NW FLOW TO CONTINUE OVER AREA
NEXT SEVERAL DAYS KEEPING REGION NEAR TO SLIGHTLY BELOW NORMAL
REGARDING TEMPERATURES AS HAS BEEN THE CASE NOW FOR MUCH OF THIS
SUMMER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT WED JUL 31 2013
TODAY...ANALYSIS SUPPORTS LOW CLOUDS AND AREAS OF FOG WITH
VISIBILITIES OF 1-3 MILES TO BURN OFF BETWEEN 8-10 AM. SUBSIDENCE
WITH DIFFLUENT LOW LEVEL FLOW AND MIXING SUGGESTS CONVECTIVE
TEMPERATURES UNLIKELY TO BE REACHED AND THUS DRY CONDITIONS
WARRANTED. A WEAK UPPER DISTURBANCE IN SOUTH DAKOTA WILL NEED TO
BE MONITORED BY DAY SHIFT BUT NOWCAST TOOLS SUGGEST IT WILL BE
DRY. LOW LEVEL THERMAL FIELDS AND MODEST BL MIXING INDICATE HIGHS
WITHIN A DEGREE OR TWO OF 80 DEGREES FOR TODAY...A WARM MID SUMMER
DAY WITH DEWPOINTS IN THE LOWER TO MIDDLE 60S FOR MODERATE HUMIDITY.
THESE TEMPERATURES ARE GENERALLY 3 TO 5 DEGREES BELOW NORMAL.
TONIGHT...LIGHT NORTHWEST WINDS SHOULD BRING IN ENOUGH DRIER AIR
AND ENOUGH MIXING TO LIMIT ANY FOG FORMATION TONIGHT. MOSTLY FAIR
SKIES WILL ALLOW FOR MINS IN THE UPPER 50S FAR NW SECTIONS TO THE
LOWER 60S ELSEWHERE. AGAIN THIS IS A FEW DEGREES BELOW NORMAL.
NICHOLS
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 305 AM CDT WED JUL 31 2013
NORTHWEST FLOW WILL KEEP TEMPERATURES BELOW NORMAL THROUGH THE
EXTENDED PERIOD WITH HIGHS GENERALLY IN THE UPPER 70S TO LOWER 80S
AND LOWS IN THE LOWER TO MID 60S.
THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME MAINLY ON
FRIDAY AND THEN AGAIN SUNDAY NIGHT INTO MONDAY AS SIGNIFICANT WAVES
MOVE ALONG IN THE FLOW.
INTERESTING THAT THE 00Z ECMWF HAS BACKED OFF ON SHOWING A POLAR VORTEX
DIVING INTO NORTHERN MN ON AUGUST 8. IT NOW DEPICTS MORE OF A BROAD
TROF IN THE EASTERN UNITED STATES WITH A 1030 MB HIGH DROPPING INTO
THE UPPER MIDWEST WITH 850 MB TEMPERATURES OF +8C INTO THE DVN CWA.
WE SHALL SEE WHAT THE NEXT RUNS SHOW.
HAASE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1234 PM CDT WED JUL 31 2013
CIGS CONTINUE TO RAISE ACROSS THE AREA WITH MVFR CIGS GENERALLY
ALONG AND EAST OF THE MISSISSIPPI. VFR WX WILL DEVELOP THROUGH
00Z/01 ACROSS THE AREA WITH A VERY WEAK FRONT PASSING THROUGH.
DIURNAL CONVECTION MAY OCCUR THIS AFTERNOON BUT OVERALL COVERAGE
SHOULD BE 15 PERCENT OR LESS. THE PROBABILITY OF A SHRA OR TSRA
AFFECTING A TAF SITE THROUGH 00Z/01 IS AT BEST 5 PERCENT. AFT
00Z/01 VFR WX IS EXPECTED WITH POSSIBLY SOME VERY LOCALIZED GROUND
FOG AROUND SUNRISE. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...HAASE
AVIATION...08
AREA FORECAST DISCUSSION...CORRECTED
NWS GOODLAND KS
116 PM MDT WED JUL 31 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 116 PM MDT WED JUL 31 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS AMPLIFIED RIDGE ACROSS
THE INTER-MOUNTAIN WEST WITH NW FLOW IN PLACE ACROSS THE HIGH
PLAINS. AT THE SURFACE A COLD FRONT IS CURRENTLY IN PLACE ACROSS
CENTRAL NEBRASKA WITH SEVERAL AREAS OF WEAK CONVERGENCE ALONG A PRE
FRONTAL TROUGH THROUGH THE CENTRAL PART OF OUR CWA...AND POSSIBLY
SEVERAL OTHER WEAK SURFACE FEATURES ASSOCIATED WITH OLD OUTFLOW FROM
OVERNIGHT CONVECTION IN THE EAST.
LATEST RAP ANALYSIS INDICATES SBCAPE IN EXCESS OF 3000 J/KG...AND
PWAT VALUES 1-1.5 INCHES ACROSS OUR CWA. THIS VERY MOIST AND
UNSTABLE AIRMASS HAS COMBINED WITH PREVIOUSLY MENTIONED SURFACE
FEATURES TO DEVELOPMENT OF SEVERAL ISOLATED THUNDERSTORMS ACROSS
THE SOUTHERN PART OF OUR CWA. WITH CU FIELD IN PLACE AND
FORCING INCREASING AHEAD OF APPROACHING COLD FRONT I WOULD
ANTICIPATE THUNDERSTORM COVERAGE TO INCREASE THROUGH THIS
AFTERNOON. RAP ALSO INDICATES 0-6KM BULK SHEER IN EXCESS OF 40KT
ACROSS THE SOUTHEASTERN HALF OF OUR CWA...AND WITH LLJ INCREASING
AROUND 00Z I WOULD EXPECT SHEER TO ONLY INCREASE. WHILE I AM
MAINLY ANTICIPATING HAIL/WIND/MULTI-CELL THREAT THROUGH
TONIGHT...TORNADOES COULDNT BE RULED OUT WITH SUPERCELLS THAT
DEVELOP CONSIDERING THE LARGE SCALE SHEER PROFILES. A SEVERE
THUNDERSTORM WATCH HAS ALREADY BEEN ISSUED FOR THE SOUTHERN HALF
OF OUR CWA...AND IF ADDITIONAL ACTIVITY DEVELOPS FURTHER NORTH OF
WATCH WE MAY NEED TO DO A LOCAL EXPANSION CONSIDERING THE
ENVIRONMENT.
WITH 0-6KM STORM MOTION GENERALLY TO THE SOUTHEAST MOST ACTIVITY
SHOULD BE TRANSITIONING OUT OF OUR CWA THIS EVENING...THOUGH WITH
GOOD THETA-E CONVERGENCE AHEAD OF LLJ WE SHOULD SEE ADDITIONAL
DEVELOPMENT TONIGHT ESPECIALLY ACROSS THE NORTHEAST.
.LONG TERM...(TOMORROW THROUGH WEDNESDAY)
ISSUED AT 1244 PM MDT WED JUL 31 2013
THE UPPER PATTERN THIS PERIOD WILL FEATURE A RIDGE CENTERED OVER
TEXAS AND OCCASIONAL SHORTWAVE TROUGHS MOVING OUT OF THE CENTRAL
AND NORTHERN ROCKIES ACROSS THE PLAINS. THIS MEANS THE SAME OLD
STORY THAT HAS BEEN RUNNING A FEW WEEKS NOW: DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS AND TEMPERATURES NEAR NORMAL. MESOSCALE
DETAILS WILL ULTIMATELY PLAY A LARGE ROLE IN DETERMINING WHERE
BETTER THUNDERSTORM CHANCES WILL BE ON ANY GIVEN DAY...BUT THEY
ARE DIFFICULT TO PREDICT BEYOND A DAY OR TWO AT BEST. AS A
RESULT...POPS WILL BE RATHER BROADBRUSHED ACROSS THE AREA. ON
THURSDAY...SEVERE STORMS WILL BE POSSIBLE GIVEN SUFFICIENT
INSTABILITY AND FAVORABLE SHEAR PROFILES. SEVERE POTENTIAL FOR THE
REMAINDER OF THE PERIOD WILL BE TIED TO SHORTWAVE IMPULSES WITH
LOW PREDICTABILITY AT THIS TIME RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1133 AM MDT WED JUL 31 2013
SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON
AHEAD OF APPROACHING COLD FRONT WITH COVERAGE DECREASING THIS
EVENING. THUNDERSTORMS WILL THEN REDEVELOP WITH SUPPORT FROM LOW
LEVEL JET AND LINGERING MOISTURE/INSTABILITY. BEST CHANCE FOR
THUNDERSTORMS THIS AFTERNOON/EVENING SHOULD BE SOUTHEAST OF BOTH
TERMINALS...WITH KGLD MOSTLY LIKELY TO SEE ACTIVITY AT TERMINAL.
OVERNIGHT ACTIVITY WILL HAVE BEST COVERAGE NEAR KMCK WITH
CLUSTER/COMPLEX OF THUNDERSTORMS DEVELOPING OVER CENTRAL NEBRASKA.
VFR CONDITIONS SHOULD PREVAIL AT BOTH KGLD AND KMCK...THOUGH LOWER
CONDITIONS ARE CERTAINLY POSSIBLE WITH THUNDERSTORM ACTIVITY.
LIGHT FOG MAY ALSO DEVELOP AROUND SUNRISE AT KMCK WITH MOIST
AIRMASS IN PLACE...WHICH COULD RESULT IN MVFR CIGS. CONFIDENCE IS
TOO LOW IN FOG TO ADD TO TAF DUE TO POSSIBLE EFFECTS OF
OVERNIGHT THUNDERSTORM ACTIVITY. WINDS SHOULD GENERALLY REMAIN
12KT OR LESS THROUGH TONIGHT AT BOTH TERMINALS WITH WINDS SHIFTING
TO THE NORTH AND THEN SOUTH- SOUTHEAST BY THURSDAY MORNING. GUSTY
WINDS MAY DEVELOP AT KGLD SHORTLY AFTER SUNRISE...WITH LIGHTER
WINDS AT KMCK WITH FRONT NEARBY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS JACKSON KY
158 PM EDT WED JUL 31 2013
.UPDATE...
ISSUED AT 158 PM EDT WED JUL 31 2013
THE SYSTEM MOVING INTO THE AREA TURNED OUT TO BE MUCH WEAKER THAN
INDICATED ON THE MODELS...SO UPDATED THE FORECAST TO DECREASE THE
AMOUNT OF RAIN EXPECTED AND TO DECREASE THE HIGH TEMPERATURES FOR
TODAY. THE REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 1130 AM EDT WED JUL 31 2013
UPDATED THE FORECAST TO BETTER TIME THE PRECIPITATION INTO THE AREA
BASED ON MODEL SOUNDINGS AND CURRENT RADAR ACTIVITY...DECREASED THE
COVERAGE AND TIMING FOR THUNDERSTORMS TODAY AND TOOK THE THUNDER OUT
OF THE TONIGHT FORECAST. STILL HAVE SOME CONCERN THAT THIS SYSTEM IS
GOING TO STAY FURTHER SOUTH THAN WHAT IS CURRENTLY FORECAST. MAY
HAVE TO DECREASE THE PROBABILITY OF PRECIPITATION FOR AREAS NORTH OF
THE MOUNTAIN PARKWAY. MAKE SOME MORE ADJUSTMENTS DURING THE 2 PM
UPDATE.
UPDATE ISSUED AT 755 AM EDT WED JUL 31 2013
HOURLY TEMP AND DEWPOINTS WERE FRESHENED UP BASED ON RECENT OBS.
UPSTREAM RADAR RETURNS STILL FAVOR HIGHER POPS IN THE FAR SOUTH. NO
SUBSTANTIAL CHANGES WERE MADE AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 340 AM EDT WED JUL 31 2013
A SHORTWAVE IS CURRENTLY WORKING THROUGH THE OH VALLEY REGION IN
WEST NORTHWEST FLOW...BUT IS PRODUCING ONLY LIGHT RAIN SHOWERS
LOCALLY. A RIDGE OF HIGH PRESSURE WAS CENTERED OVER THEE SOUTHERN
ROCKIES WITH AN UPPER LEVEL LOW AND TROUGH CONTINUING TO EXIT THE
NORTHEASTERN CONUS INTO THE MARITIMES. ALSO IN THE NORTHERN
STREAM...A SHORTWAVE TRACKING NEAR THE US/CANADIAN BORDER IS
APPROACHING THE UPPER MS VALLEY AND WESTERN ONTARIO. HEAVIER
PRECIPITATION THUS FAR HAS BEEN CONFINED TO SOUTHERN MIDDLE AND
EASTERN TN AND THE NORTHERN GULF COAST STATES. THERE HAS ALSO BEEN A
SLIGHT INCREASE IN CONVECTION OVER WESTERN KY.
THE SHORTWAVE NOW WORKING THROUGH THE OH VALLEY AND INTO THE
APPALACHIAN REGION AND THE SHORTWAVE WORKING TOWARD THE WESTERN GREAT
LAKES WILL EVENTUALLY BECOME A BIT MORE PHASED BY THUS AND LEAD TO A
RETURN TO A MORE AMPLIFIED EASTERN/NORTHEASTERN CONUS THROUGH AND
ROCKIES/PLAINS RIDGE. MEANWHILE A SFC LOW IS LAGGING THE UPPER LEVEL
SHORTWAVE WORKING THROUGH THE OH VALLEY. THIS LOW WILL DRIFT THROUGH
THE LOWER OH VALLEY REGION AND REACH CENTRAL KY THIS EVENING...EVENTUALLY
BECOMING DIFFUSE AND MORE OR LESS MERGING WITH A COLD FRONT ASSOCIATED
WITH THE TROUGH WORKING THROUGH ONTARIO AND THE GREAT LAKES REGION
TONIGHT AND INTO THURSDAY. THE SFC COLD FRONT SHOULD CROSS THE CWA ON
THURSDAY.
THE 0Z NAM AND THE 4Z HRR GENERALLY INDICATE REDEVELOPMENT OF
STRONGER CONVECTION THAN THE LIGHT SHOWERS CURRENTLY OVER THE CWA
TOWARD DAWN AND THEN WORK THIS INTO EASTERN KY THIS MORNING AND INTO
THIS AFTERNOON. THE NAM HAS BULLSEYE OF QPF OVER THE LAKE CUMBERLAND
REGION...BUT MUCH OF THE OTHER GUIDANCE HAS HIGHER QPF NEAR THE TN
BORDER...AND IS NOT NEARLY AS MUCH. CONFIDENCE IN THE EVOLUTION OF
THIS CONVECTION IS BELOW AVERAGE...BUT THE MODEL CONSENSUS IS THAT
BEST CHANCES SHOULD BE ACROSS THE SOUTH TODAY. THE 5Z HRRR HAS THROWN
A BIT MORE UNCERTAINTY INTO THE PICTURE...ESPECIALLY ACROSS THE NORTH
WITH IT SUGGEST COULD LARGELY REMAIN DRY.
WE HAVE OPTED TO GO VERY CLOSE TO HPC QPF WHICH LED TO LOWER AMOUNTS
THAN THE NAM OVER THE SOUTH WITH THE HIGHEST POPS OVER THE SOUTHERN
CWA. HOWEVER...THIS STILL YIELDS NEARLY AN INCH OF RAIN THROUGH
TONIGHT. ALTHOUGH A SHORTWAVE CURRENTLY WORKING THROUGH THE OH VALLEY
AND ANOTHER UPSTREAM WILL WORK ACROSS THE AREA THIS AFTERNOON AND THE
SFC LOW WILL GRADUALLY APPROACH THE AREA...CLOUD COVER SHOULD LIMIT
OVERALL INSTABILITY. THE CLOSEST LIGHTNING AT PRESENT IS OVER WESTERN
KY. THUS WE HAVE KEPT COVERAGE OF THUNDER AT ISOLATED TO SCATTERED
LEVELS THROUGH THIS EVENING WITH HIGHER COVERAGE OF SHOWERS.
HOWEVER... CHANCES FOR CONVECTION WILL LINGER THROUGH MOST OF THE
PERIOD...UNTIL LATE ON THU WHEN A COLD FRONT WILL SWEEP THE DEEPER
MOISTURE EAST AND SOUTHEAST OF THE AREA.
MOS GUIDANCE WAS TOO WARM WITH HIGHS ON TUE AND WE HAVE WENT ON THE
COLDER END OF GUIDANCE FOR MAX T TODAY.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 AM EDT WED JUL 31 2013
MODELS ARE AGREEING A BIT MORE HEADING INTO THE UPCOMING
WEEKEND...SO CONFIDENCE IN THE FORECAST IS INCREASING. STARTING
THURSDAY NIGHT...HIGH PRESSURE WILL BE BUILDING INTO THE
REGION...SETTING UP A DRY AND PLEASANT END TO THE WEEK. A SHORTWAVE
TROUGH WILL THEN DRAG A SURFACE WARM FRONT BACK TO THE NORTHEAST
LATE FRIDAY NIGHT INTO SATURDAY WITH ISENTROPIC ASCENT DEVELOPING
OVER THE REGION. THIS WILL YIELD THE POTENTIAL FOR A WET PERIOD ON
SATURDAY...AS THE WARM FRONT STALLS OVER THE AREA. A SECONDARY
SHORTWAVE PUSHING ACROSS THE GREAT LAKES WILL THEN DRAG A COLD FRONT
SOUTHWARD ACROSS THE OHIO RIVER VALLEY SATURDAY NIGHT INTO EARLY
SUNDAY...WITH ANOTHER PERIOD OF UNSETTLED WEATHER EXPECTED. THIS
FRONTAL BOUNDARY WILL GET SHOVED SOUTHWARD ON SUNDAY WITH DRY
WEATHER RETURNING TO FINISH OUT THE WEEKEND. HOWEVER...THE ACTIVE
WEATHER WILL CONTINUE AS ANOTHER SHORTWAVE PUSHES EAST INTO THE AREA
ON MONDAY...BRINGING ANOTHER ROUND OF SHOWERS AND PERHAPS A
THUNDERSTORM TO THE AREA. DRIER WEATHER MAY RETURN BY TUESDAY AND
WEDNESDAY...BUT GIVEN THE TROUGH OVER THE REGION...ADDITIONAL WAVES
OF UNSETTLED WEATHER COULD IMPACT THE REGION. HIGHS THROUGH THE
PERIOD WILL BE A TOUCH BELOW NORMAL WITH A GENERAL TROUGH OVER THE
EASTERN US...KEEPING TEMPERATURES UNUSUALLY COOL FOR THIS TIME OF
YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 158 AM EDT WED JUL 31 2013
THE TAF GUIDANCE HAS BEEN ALL OVER THE PLACE AND DID NOT EVEN CAPTURE
CURRENT CONDITIONS VERY WELL. AS SUCH...CONFIDENCE IS A BIT LOWER THAN
NORMAL. A WHOLE LOT IS GOING TO DEPEND ON HOW MUCH RAIN FALLS TONIGHT
AND HOW MUCH CLOUD COVER THERE IS. EXPECT TO SEE SOME VLIFR TONIGHT
AS THERE IS SUFFICIENT LOW LEVEL MOISTURE. THIS IS THE KIND OF
FORECAST WHERE IF YOU DO NOT GET THE VSBY RIGHT...THE STRATUS COULD
STILL PUT THE FORECAST IN THE CORRECT CATEGORY. EXPECTING A COMBINATION
OF THE FOG AND STRATUS TONIGHT WILL THIS FALL LIKE SUMMER SYSTEM.
ALSO EXPECT THE CLEARING TO TAKE LONGER THAN NORM FOR THE MORNING
FORECAST
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
255 PM EDT WED JUL 31 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO MOVE OFF THE COAST TODAY AND A COLD
FRONT WILL APPROACH FROM THE OHIO VALLEY TONIGHT. THE COLD FRONT
WILL PASS THROUGH THE AREA LATE THURSDAY INTO THURSDAY NIGHT AND
HIGH PRESSURE WILL RETURN FOR FRIDAY. HIGH PRESSURE WILL MOVE OFF
THE COAST SATURDAY AND ANOTHER COLD FRONT WILL IMPACT THE AREA
LATE SATURDAY INTO SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE HAS MADE IT OFF THE MID ATLANTIC COAST THIS
AFTERNOON. SOUTHERLY FLOW AROUND THE HIGH HAS INCREASED ACROSS LWX
WITH PWATS SLIGHTLY INCREASING. AN UPPER LEVEL DISTURBANCE HAS
MOVED EASTWARD FROM THE OHIO VALLEY AND IS ACROSS NORTH CENTRAL
VA. ANOTHER AREA OF ENERGY IS OVER SOUTHERN WV AND SW VA. ISOLATED
SHOWERS HAVE SPREAD OVER THE HIGHLANDS...CENTRAL FOOTHILLS AND
NOVA THIS MORNING. THIS SHORTWAVE ENERGY WILL MOVE EASTWARD
THROUGH THE AFTERNOON CAUSING HEIGHTS TO FALL. ISOLATED AREAS OF
THUNDERSTORMS HAVE FORMED OUTSIDE OF LWX AND ALONG DIFFERENTIAL
HEATING BOUNDARIES INCLUDING ONE NEAR RICHMOND. CU CAN ALSO BE
SEEN ON VISIBLE ACROSS MOST AREAS ALONG THE EAST COAST AND
NORTHEAST WHERE BREAKS CAUSED THEM TO GET MORE HEATING. CLOUDS
HAVE BEEN COVERING MOST OF THE MID ATLANTIC WITH THE EXCEPTION OF
NE MD TODAY. THIS AREA IS STILL DEALING WITH SUBSIDENCE FROM
DEPARTING HIGH BUT AREA COULD SEE POP UP SHOWERS THIS AFTERNOON.
A MILD DAY OF TEMPERATURES EXPECTED AS PLACES IN THE HIGHLANDS
AND CENTRAL FOOTHILLS ARE NOT OUT OF THE 60S YET. TEMPS ARE
EXPECTED TO REACH THE UPPER 70S TO THE MID 80S EAST OF THE BLUE
RIDGE.
THERE ARE A FEW DIFFERENCES IN THE MODELS FOR LATER THIS EVENING AND
OVERNIGHT. THE 12Z NAM HAS MANY VORT MAXES MOVING UP THE EAST COAST
THIS EVENING AND OVERNIGHT WHICH WOULD ULTIMATELY LEAD TO HIGHER
CHANCE OF SHOWERS. GFS/ECMWF SHOW SHORTWAVE ENERGY MOVING OFF THE
COAST THIS EVENING WITH MOISTURE INCREASING ACROSS THE HIGHLANDS.
ELSEWHERE...LITTLE FORCING MAY PRODUCE ISOLATED SHOWERS OVERNIGHT.
HI RES MODELS SUCH AS THE WRF AND HRRR HAVE ALSO SHOWN SHOWERS
MOVING UP THE EAST COAST THIS EVENING BUT ARE CURRENTLY NOT
INTIALZING WELL. LEANED TOWARDS THE GFS/ECWMF IN FORECAST SINCE
THEY HAVE TRACKED THE LATEST SHORTWAVE AND INTIALIZED THE BEST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
COLD FRONT CROSSES THE MID ATLANTIC THURSDAY. PWATS INCREASE TO 1.8
INCHES AND SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED.
COVERAGE OF SHOWERS WILL INCREASE FROM THE HIGHLANDS THURSDAY
MORNING TO THE CHESAPEAKE BAY BY THE EVENING. SYSTEM SEEMS
PROGRESSIVE AND WPC GUIDANCE HAS AROUND AN INCH OF PRECIPITATION
EXPECTED. LOCALLY HIGHER AMOUNTS ARE POSSIBLE IN THUNDERSTORMS AS
INSTABILITY INCREASES AHEAD OF THE FROPA. CLOUD COVER WILL PLAY A
ROLE IN DAMPENING A SVR THREAT BUT FLASH FLOODING WILL BE POSSIBLE. 1-HR
FFG OVER NE MD IS LOWER THAN OTHER AREAS EAST OF THE BLUE RIDGE.
THIS AREA WILL NEED TO BE WATCHED IF THUNDERSTORMS APPROACH.
PREVIOUS DISCUSSION...
THURSDAY NIGHT...QUICK CUTOFF FROM PRECIP AS THE SFC
TROUGH MOVES EAST FROM THE CWA THURSDAY EVENING. CD FROPAS ARE
RARE FOR SUMMER... BUT CONSENSUS HAS THE TROUGH REACHING THE MID-
ATLANTIC COASTLINE THROUGH THE OVERNIGHT. MAV/MET/SREF BLEND MAKES
FOR MIN TEMPS LOW TO MID 60S INLAND...AROUND 70F FOR URBAN AND
NEARSHORE LOCALES. THE RAIN ON THURSDAY SHOULD LOWER THE WATER
TEMPS A BIT...BUT THEY ARE CURRENTLY AROUND 80F.
FRIDAY...DOWNSLOPING FLOW...SUNSHINE...AND LESS HUMIDITY LEAD TO
HIGHER TEMPS THAN RAINY THURSDAY. MID 80S MAX TEMPS...NEAR NORMAL.
DRY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
UPR TROUGH PERSISTS OVER THE ERN CONUS THROUGH THE FORECAST PERIOD.
SFC TROUGH CROSSES THE MID-ATLANTIC SATURDAY INTO SUNDAY WITH CHANCE
POPS. MORE CANADIAN HIGH PRESSURE SUNDAY AND MONDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
CLOUDS HAVE THICKENED TODAY AND A FEW SHOWERS HAVE FORMED AND
DIMINISHED ACROSS THE AREA. EXPECT COVERAGE TO INCREASE THROUGH
THURSDAY AS A COLD FRONT APPROACHES FROM THE WEST.
SOUTHERLY FLOW WILL CONTINUE AHEAD OF COLD FRONT AND CLOUDS WILL
LOWER LEADING TO MVFR AND IFR CONDITIONS. VSBYS MAY BE REDUCED TO
MVFR LEVELS IN ANY PRECIPITATION...ESPECIALLY LATER THIS EVENING
AND OVERNIGHT.
HEAVY SHOWERS/THUNDERSTORMS THURSDAY AHEAD OF A WEAK COLD FRONT. IFR
CONDS LIKELY IN STRONGER ACTIVITY SLY FLOW GUSTS UP TO 20
KT...HIGHER IN THUNDERSTORMS. WLY/NWLY FLOW THURSDAY NIGHT THROUGH
FRIDAY IN VFR CONDS. SFC TROUGH SATURDAY INTO SUNDAY WITH SCATTERED
THUNDERSTORMS.
&&
.MARINE...
SOUTHERLY FLOW AROUND THE SFC HIGH WILL CONTINUE THROUGH THURSDAY.
WINDS 5-10 KNOTS EXPECTED ON THE WATERS THE REST OF THE AFTERNOON
BEFORE INCREASING AS COLD FRONT NEARS. S-SE FLOW WITH GUSTS UP TO
20 KNOTS EXPECTED OVERNIGHT. A SMALL CRAFT ADVISORY IS IN EFFECT
TONIGHT FOR THE MARYLAND CHESAPEAKE BAY SOUTH OF POOLES ISLAND AND
THE LOWER TIDAL POTOMAC RIVER.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TONIGHT AND THURSDAY AS
FROPA APPROACHES FROM THE WEST. WLY/NWLY FLOW AROUND 15 KT
THURSDAY NIGHT INTO FRIDAY. WEAK DISTURBANCE SATURDAY INTO SUNDAY
BRINGS SCATTERED THUNDERSTORMS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES HAVE INCREASED TO AROUND A HALF FOOT ABOVE NORMAL
THIS AFTERNOON. SOUTHERLY FLOW WILL CONTINUE THROUGH MOST OF
THURSDAY AND MINOR COASTAL FLOODING WILL BE POSSIBLE NEAR
SENSITIVE LOCATIONS DURING THE HIGH TIDE CYCLE LATE TONIGHT INTO
THURSDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT
THURSDAY FOR ANZ531>534-537-539>541-543.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT THURSDAY FOR ANZ530-
536-538-542.
&&
$$
SYNOPSIS...HAS
NEAR TERM...HAS
SHORT TERM...HAS/BAJ
LONG TERM...BAJ
AVIATION...BAJ/HAS
MARINE...BAJ/HAS
TIDES/COASTAL FLOODING...HAS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
312 PM EDT WED JUL 31 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 311 PM EDT WED JUL 31 2013
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THROUGH THIS EVENING AS
A WEAK COLD FRONT PASSES THROUGH. CONDITIONS DRY OUT ON THURSDAY
BEFORE RAIN CHANCES RETURN FRIDAY MORNING WITH A WEAK UPPER AIR
WAVE. TEMPERATURES WILL REMAIN A LITTLE COOL WITH HIGHS IN THE
MID TO UPPER 70S THROUGH THE WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 311 PM EDT WED JUL 31 2013
EXPECT SHOWERS AND ANY POSSIBLE THUNDERSTORMS TO END BY THIS
EVENING WITH ONLY A SLIGHT CHANCE FOR SHOWERS AND STORMS TO THE
EAST TOMORROW AFTERNOON. SOLID CHANCE FOR RAIN RETURNS FRIDAY
MORNING WITH THE NEXT SHORTWAVE ROTATING THROUGH THE NORTHWEST
FLOW.
WE COULD CERTAINLY SEE SOME STORMS IMPACT SOUTHWEST LOWER MICHIGAN
AS THEY MOVE IN FROM WISCONSIN. STORMS ARE CURRENTLY DEVELOPING IN
CENTRAL WISCONSIN ALONG THE COLD FRONT. NOT OVERLY IMPRESSED...THE
BEST CHANCE FOR THUNDERSTORMS IS CERTAIN TO THE NORTHEAST. CLOUD
COVER HAS LIMITED INSTABILITY AND THE UPPER AIR DIVERGENCE IS MORE
FAVORABLE IN NORTHER LOWER MICHIGAN. THE HRRR SUGGESTS A WEAKENING
BAND OF SHOWERS WILL ENTER WEST MICHIGAN EARLY THIS EVENING...SO
WE BUMPED UP POPS SLIGHTLY.
AREAS OF FOG ARE LIKELY OVERNIGHT WITH THE RAIN COMING TO AN END BY
MIDNIGHT OR SO AND DRIER AIR FILTERING IN BEHIND THE FRONT. CLOUDS
DURING THE DAY HAVE LIMITED HIGH TEMPS AND CLOUDS CLEARING
OVERNIGHT AS WELL AS LIGHT WINDS ALL SUGGEST FAVORABLE CONDITIONS
FOR FOG DEVELOPMENT.
DUE TO THE POSITIONING OF THE UPPER LEVEL JET AND LIMITED
INSTABILITY...WE FEEL THE BEST AREA FOR SHOWERS AND STORMS ON
THURSDAY AFTERNOON IS EASTERN LWR MICHIGAN. THE UPPER JET FLOWS
DIRECTLY OVER US ON FRIDAY BRINGING THE POTENTIAL FOR ADDITIONAL
SHOWERS...HOWEVER THE ENTRANCE AND EXIT REGION DYNAMICS PASS TO
THE NORTHEAST AND SOUTHWEST. THE HEAVIER QPF AMOUNTS ARE RESERVED
TO THESE AREAS FOR THESE REASONS.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 311 PM EDT WED JUL 31 2013
SEASONABLY COOL TEMPERATURES ARE EXPECTED THROUGH THE LONG RANGE
FORECAST PERIOD WITH A PERSISTENT UPPER LEVEL TROUGH IN PLACE OVER
THE NORTHERN GREAT LAKES REGION THAT WILL AMPLIFY OVER OUR REGION
TOWARD THE MIDDLE PORTION OF NEXT WEEK.
A HIGH PRESSURE RIDGE SHOULD BRING FAIR AND DRY BUT SEASONABLY COOL
WEATHER SATURDAY THROUGH SUNDAY. THE FORECAST FOR THE EARLY TO
MIDDLE PORTION OF NEXT WEEK BECOMES A LITTLE MORE UNCERTAIN SINCE THE
UPPER LEVEL TROUGH WILL AMPLIFY OVER THE NORTHERN GREAT LAKES REGION
AND SEVERAL SHORTWAVES WILL DROP DOWN FROM THE NW. THIS TYPE OF
PATTERN COULD BRING SOME SCATTERED SHOWERS AND A FEW STORMS MONDAY
THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1230 PM EDT WED JUL 31 2013
VARIABLE CONDITIONS WILL CONTINUE THIS AFTERNOON RANGING MAINLY FROM
MVFR TO IFR DUE TO LOW CIGS AND SCATTERED SHOWERS. WE CANNOT
COMPLETELY RULE OUT DEVELOPMENT OF AN ISOLATED STORM LATE THIS
AFTERNOON BUT THE BETTER CHANCE FOR STORMS WILL STAY EAST OF ALL OUR
TERMINALS OVER EASTERN LOWER MICHIGAN INTO ONTARIO CANADA THIS
EVENING.
A FEW SCATTERED SHOWERS WILL LINGER INTO THIS EVENING BEFORE THE
SHOWERS END AND CONDITIONS WILL GRADUALLY IMPROVE FROM MVFR/IFR TO
VFR OVERNIGHT THROUGH 18Z THURSDAY. THERE IS A SMALL CHANCE OF
PATCHY FOG DURING THE EARLY MORNING HOURS THURSDAY PARTICULARLY IF
SKIES TRY TO CLEAR OVERNIGHT... BUT THERE IS NOT ENOUGH POTENTIAL IN
IT TO WARRANT INCLUSION IN THE TERMINAL FCSTS AT THIS TIME.
&&
.MARINE...
ISSUED AT 311 PM EDT WED JUL 31 2013
WINDS WILL PICK UP ON THURSDAY BEHIND THE COLD FRONT OUT OF THE
NORTHWEST. WINDS WILL BE IN THE 10 TO 15 KT RANGE...KEEPING WINDS
AND WAVES BELOW SMALL CRAFT ADVISORY CRITERIA.
&&
.HYDROLOGY...
ISSUED AT 311 PM EDT WED JUL 31 2013
LIMITED QPF WILL RESULT IN FEW HYDRO CONCERNS THROUGH THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...EBW
SHORT TERM...WDM/EBW
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...WDM/EBW
MARINE...WDM/EBW
AREA FORECAST DISCUSSION
NWS DULUTH MN
1252 PM CDT WED JUL 31 2013
.AVIATION...
COLD AIR ALOFT HAS RESULTED IN SCATTERED CU DEVELOPMENT AROUND 3-4
KFT ACROSS THE NORTHLAND. VERY ISOLATED SHOWERS AND A POSSIBLE
THUNDERSTORM WILL BE FOUND THIS AFTERNOON...MAINLY OVER THE
MINNESOTA ARROWHEAD AND NORTHERN WISCONSIN. HAVE KEPT VCSH AT KHIB
AND KHYR THROUGH 00Z. THE STEEP LAPSE RATES HAVE ALSO ALLOWED FOR
DEEP MIXING AND GUSTY WEST-NORTHWEST WINDS. EXPECT FREQUENT GUSTS
OF 20-25 KT THROUGH THE EARLY EVENING. WINDS WILL DIMINISH QUICKLY
AROUND SUNSET. SIMILAR CONDITIONS WITH ISOLATED SHOWERS AND GUSTY
NORTHWEST WINDS WILL BE FOUND THURSDAY.
&&
.PREV DISCUSSION... /ISSUED 1030 AM CDT WED JUL 31 2013/
UPDATE...MADE MINOR TWEAK TO SKY FCST TODAY AND POPS. MAIN THEME
REMAINS THE PROGRESSION OF THE SFC COLD FRONT SOUTH AND EAST OF THE
CWA THIS AFTERNOON. RW/TRW POTENTIAL REMAINS OVER WISC ZONES WITH
FRONTAL CONVERGENCE/INSTABILITY...AND UNDER STEEPENING LAPSE RATES
OVER NRN MN ZONES. LATEST RAP13 SHOWS AN AREA OF 85/70H LAPSE
RATES OF 6C/KM TO 6.5C/KM PUSHING ACROSS BORDERLAND. DEEP LAYER
MOISTURE IS QUESTIONABLE OVER NWRN CORNER OF CWA. 85/70H RH IS
70 TO 90 PERCENT ACROSS ARROWHEAD SO BETTER CHC APPEARS TO BE IN
THAT LOCATION. PUSHED MAX TEMPS A FEW DEGREES HIGHER NEAR LAKEFRONT
IN DLH VICINITY AS WESTERLY WINDS DOWNSLOPE TO SUPERIOR. GUSTY
WINDS WILL INCREASE TODAY OVER NE MN ZONES AS MIXING LAYER DEEPENS
SIGNIFICANTLY AND TAPS INTO HIGHER WINDS ALOFT.
PREV DISCUSSION... /ISSUED 356 AM CDT WED JUL 31 2013/
SHORT TERM...TODAY THROUGH THURSDAY.
AT 330 AM...ISOLATED SHOWERS AND THUNDERSTORMS WERE DEVELOPING
ACROSS THE REGION. THE STRONGEST STORM WAS MOVING QUICKLY TOWARD
THE WESTERN PORTION OF THE CWA...SPECIFICALLY CASS COUNTY.
TEMPERATURES AT 3 AM RANGED FROM THE MID 50S TO THE MID 60S.
PATCHY FOG ALSO WAS FOUND ACROSS THE CWA. THERE HAS BEEN SOME
IMPROVEMENT AS THICKER CLOUDS HAVE MOVED IN.
THE MAIN FOCUS FOR TODAY IS ON THUNDERSTORM POTENTIAL. A FRONTAL
BOUNDARY WILL CONTINUE TO MOVE TO THE SOUTH AND EAST ACROSS THE
REGION TODAY...WITH ISOLATED THUNDERSTORMS DEVELOPING ALONG AND
AHEAD OF THE FRONT. IN ADDITION...ANOTHER TROUGH WILL FOLLOW
BEHIND THE FRONT. TOUGH TO PUT TOO MUCH INTO TIMING TODAY BUT
THINK ISOLATED WORDING WILL COVER IT WELL. IN ADDITION...THERE
SHOULD BE SOME DIURNAL SHOWERS AND STORMS ACROSS THE NORTH BY THIS
AFTERNOON. THE HRRR...4 KM NMM AND RAP ARE ALL INDICATING THAT
THERE WILL BE SOME DEVELOPMENT DUE TO DAYTIME HEATING WITH SOME
WEAK INSTABILITY BY THIS AFTERNOON. THE BEST CHANCE FOR SEEING
SOME STRONGER STORMS IS IN EC MN AND NW WI...WHERE SPC HAS A 5
PERCENT WIND AND HAIL CONTOUR.
WITH THE LOSS OF DAYTIME HEATING WE SHOULD SEE A QUICK DEMISE TO
THE SHOWERS AND THUNDERSTORMS TONIGHT. WITH COLD AIR ALOFT AND AN
UPPER LEVEL SHORTWAVE AND VORT MAX...WE SHOULD SEE MORE DIURNAL
ACTIVITY ON THURSDAY SO WILL CONTINUE WITH SMALLER POPS ACROSS
MUCH OF THE AREA BY AFTERNOON.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
THURSDAY NIGHT A WEAK TROUGH AXIS CONTINUES TO MOVE ACROSS THE
FORECAST AREA AS A SHORTWAVE MOVES THROUGH THE UPPER FLOW. SOME
MODELS ARE GENERATING A NICE MCS OVER THE FORECAST AREA AND THEN
DRIVING IT SOUTHEAST ALONG WITH THE UPPER LEVEL FLOW. BETTER
INSTABILITY WILL BE FARTHER SOUTH ALONG THE STRONGER BAROCLINIC ZONE
ACROSS SOUTH DAKOTA EXTENDING INTO IOWA...SO AM NOT TERRIBLY EXCITED
ABOUT ANYTHING SIGNIFICANT THURSDAY NIGHT...BUT AM CARRYING SOME
CHANCE POPS FOR AT LEAST A PORTION OF THE AREA. MUCH IS GOING TO
DEPEND ON THE TIMING OF THE SHORTWAVE WHICH IS HANDLED IN VARYING
WAYS BY THE MODELS THIS MORNING. MIN TEMPS TO BE KEPT MILD BY EXTRA
CLOUD COVER...AND WILL BE MAINLY IN THE 50S.
FRIDAY THROUGH MOST OF SUNDAY A STRONG SURFACE RIDGE BUILDS INTO
THE REGION. ON FRIDAY BEFORE THE RIDGE GETS FIRMLY ESTABLISHED HAVE
SOME SLIGHT CHANCE POPS AS CYCLONIC FLOW ALOFT INTERACTS WITH SOME
LINGERING LOW LEVEL MOISTURE AND CONVERGENCE. TEMPERATURES COOL OFF
FAIRLY SIGNIFICANTLY BY FRIDAY NIGHT AND SATURDAY...WITH ANOTHER
NIGHT WITH SOME 40S ALL THREE NIGHTS...AND HIGHS ONLY IN THE LOW 70S
SATURDAY.
LATE SUNDAY...SUNDAY NIGHT AND MONDAY THINGS BEGIN TO SHIFT AS ANOTHER
SHORTWAVE DIVES THROUGH THE UPPER LEVEL FLOW AND THE SURFACE RIDGE
SHIFTS EAST OF THE AREA. THIS ALLOWS THE BAROCLINIC ZONE TO SHIFT
NORTH INTO SOUTH DAKOTA AND SOUTHERN MINNESOTA...AND WITH THE UPPER
LEVEL JET OVER NORTHERN MINNESOTA BY SUNDAY NIGHT AN MCS CAN BE
EXPECTED TO GENERATE SOMEWHERE NEAR OR SOUTH OF THE FORECAST AREA
THAT NIGHT. HOWEVER...AM NOT TOO CONVINCED IT WILL BE THIS FAR
NORTH AND HAVE LIMITED HIGHER POPS TO THE SOUTHERN COUNTIES WITH
LESS ACROSS THE NORTH. TEMPERATURES REMAIN COOL WITH HIGHS IN THE
LOW 70S. THE NORTHWEST FLOW CONTINUES INTO TUESDAY AND THERE ARE
SOME INDICATIONS THAT WE WILL HAVE ANOTHER SHORTWAVE DUE THROUGH
WITH ANOTHER CHANCE OF PRECIPITATION...BUT CONFIDENCE IS NOT VERY
HIGH AT THIS TIME AND HAVE LIMITED POPS. TEMPERATURES TO REMAIN
NEAR OR SLIGHTLY BELOW NORMAL.
&&
.POINT TEMPS/POPS...
DLH 76 53 74 55 / 20 10 20 20
INL 71 49 74 51 / 20 20 30 10
BRD 76 52 76 55 / 20 10 10 10
HYR 79 50 76 53 / 20 10 20 30
ASX 76 52 75 54 / 20 20 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1240 PM CDT WED JUL 31 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT WED JUL 31 2013
TODAY AND TONIGHT...HIGH PRESSURE HAS BUILT INTO SCNTL NEB IN WAKE
OF LAST NIGHTS CRUSHING TSTM EVENT. ALL INDICATIONS ARE THE
ATMOSPHERE WILL REMAIN NEARLY QUIET THIS AFTERNOON AND THIS EVENING.
THERE IS PERHAPS THE POTENTIAL FOR DESTABILIZATION THIS AFTN ACROSS
THE CNTL HIGH PLAINS. ISOLATED STORMS COULD DEVELOP ACROSS WRN NEB
WHICH WOULD MOVE EAST AND DISSIPATE IN THE EVENING ACROSS NCNTL NEB.
THERE IS ALSO THE POTENTIAL FOR DESTABILIZATION ACROSS SWRN AND
SCNTL NEB THIS AFTN AND THIS EVENING NORTH OF A SFC FRONT CURRENTLY
LOCATED ACROSS KS AND NERN COLORADO. SPC HAS OUTLOOKED FRONTIER
COUNTY NORTHEAST THROUGH CUSTER AND HOLT COUNTIES IN THEIR DAY 1
OUTLOOK FOR SEVERE TSTM DEVELOPMENT.
FOR THIS MORNING...A CLUSTER OF SHOWERS AND TSTMS ACROSS SWRN SD
COULD SWEEP EAST AND SOUTHEAST THROUGH PARTS OF NWRN AND NCNTL NEB.
THIS IS HIGHLY SPECULATIVE GIVEN THE MODEL DYNAMIC ADJUSTMENT
PROCESS DURING THE FIRST 12 HRS. THE RAP AND HRRR HAVE THEIR OWN
IDEAS. THE RAP SHOWS SCATTERED STORM COVERAGE ACROSS NCNTL NEB WHILE
THE HRRR IS SLOWER AND FARTHER EAST JUST BRUSHING HOLT AND BOYD
COUNTIES. THE FCST IS FOR ISOLATED SHRA/TSTM COVERAGE GIVEN CURRENT
RADAR TRENDS.
TEMPERATURES TODAY ARE ON THE COOL SIDE OF AN ENVELOP OF MID 70S TO
NEAR 90. A BLEND OF MODEL DATA PLUS BIAS CORRECTION YIELDED LOW TO
UPPER 80S FOR HIGHS UNDER SCATTERED AND BROKEN CLOUD COVER.
LASTLY...THE MODELS CONTINUE TO ADVERTISE A LATE NIGHT MCS DROPPING
THROUGH NWRN NEB AROUND 06Z AND THEN PEDDLING EAST AND SOUTHEAST
THROUGH MUCH OF NCNTL NEB BETWEEN 06Z AND 12Z. THE 06Z NAM SHOWS
MODEST ELEVATED CAP AROUND 1000 J/KG AND AN MCS DROPPING MORE SOUTH
THROUGH SCNTL NEB BY 12Z. GIVEN THE TRACK OF THE STORMS TUESDAY
EVENING THIS SOLN HAS SOME CREDIBILITY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 349 AM CDT WED JUL 31 2013
ACTIVE WEATHER TO CONTINUE THROUGH THE PERIOD. A WARM FRONT WILL
EXTEND WEST TO EAST ACROSS THE AREA THURSDAY AND BE THE FOCUS FOR
TSTM DEVELOPMENT. CONTINUED NORTHWEST FLOW ALOFT WILL COMBINE WITH
EAST TO SOUTHEAST WINDS AT THE SFC...PRODUCING FAVORABLE SHEAR FOR
SUPERCELL TSTMS WITH LARGE HAIL AND DAMAGING WIND POTENTIAL. WILL
ALSO HAVE TO WATCH FOR HEAVY RAIN/FLOODING POTENTIAL...AS SOME AREAS
HAVE RECEIVED WELL OVER TWO INCHES OF RAIN THE LAST FEW DAYS.
VALENTINE FOR INSTANCE HAD OVER TWO INCHES OF RAIN JUST LAST
NIGHT.
THE AFOREMENTIONED FRONT WILL REMAIN IN THE AREA FRIDAY THROUGH THE
UPCOMING WEEKEND...AND CONTINUE TO BE THE FOCUS FOR AT LEAST
SCATTERED TSTM DEVELOPMENT. RICH MOISTURE...SHEAR...AND
INSTABILITY...WILL CONTINUE TO BRING THE THREAT FOR A FEW SEVERE
STORMS AS WELL AS LOCALIZED HEAVY RAIN.
BY EARLY NEXT WEEK...HIGH PRESSURE WILL TRY TO NUDGE SOUTH INTO THE
AREA FROM THE NORTHERN PLAINS/CANADA. THIS MAY FORCE THE RICHER
MOISTURE SOUTH INTO KANSAS AND OKLAHOMA...BUT STILLS APPEARS TO BE
ENOUGH MOISTURE IN THE AREA TO CONTINUE SOME SLIGHT AND LOW END
CHANCES FOR TSTM ACTIVITY.
TEMPERATURE WISE...WITH THE FRONT REMAINING IN THE AREA...ALONG WITH
CLOUDS AND PRECIPITATION FROM TIME TO TIME...HIGHS WILL REMAIN
GENERALLY IN THE 80S. OVERNIGHT LOWS WILL BE MILD WITH THE INCREASED
MOISTURE CONTENT IN THE AIR...WITH MOST LOCALS REMAINING IN THE 60S
AT NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1239 PM CDT WED JUL 31 2013
THE 18Z TAF ISSUANCE FOR KLBF AND KVTN. STRATUS DECK CONTINUES TO
BUILD TO THE SOUTHWEST ACROSS PORTIONS OF THE NORTH CENTRAL AND
CENTRAL SANDHILLS EARLY THIS AFTERNOON. MVFR FLIGHT CEILINGS HAVE
BEEN REPORTED AT BOTH KVTN AND KLBF...THUS WILL INCLUDE A MENTION AT
BOTH SITES FOR NOW THROUGH 00Z. THERE IS A BIT OF UNCERTAINTY ON
WHETHER OR NOT THE STRATUS WILL BREAK...SO UPDATES MAY BE NEEDED.
OTHERWISE THUNDERSTORM WILL INCREASE IN COVERAGE OVERNIGHT FROM WEST
TO EAST...WITH THE POTENTIAL OF VISIBILITY REDUCTIONS FROM HEAVY
RAIN. THE MOST SIGNIFICANT CONVECTION IS EXPECTED TO FORM LATE
TONIGHT WITH STORMS DEVELOPING ACROSS THE CNTL HIGH
PLAINS...BETWEEN 03Z- 06Z AND SPINNING SOUTH AND EAST THROUGH WRN
AND NCNTL NEB THROUGH 12Z THURSDAY. NOTE THAT THE NAM SHOWS TWO
ROUNDS OF STORMS RIPPING THROUGH THE FCST AREA AND THIS SEEMS
CREDIBLE GIVEN THE VERY ACTIVE WEATHER PATTERN UNDERWAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
214 PM EDT WED JUL 31 2013
.SYNOPSIS...
SHOWERS AND SCATTERED THUNDERSTORMS WILL OVERSPREAD THE REGION
TONIGHT AND THURSDAY AS A COLD FRONT APPROACHES THEN CROSSES THE
REGION. LINGERING MOISTURE AND SOMEWHAT UNSTABLE AIR BEHIND THE
FRONT MAY BRING A FEW MORE SHOWERS ON FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
CLOUDS WILL CONTINUE TO OVERSPREAD THE REGION AND THICKEN THIS
EVENING AS MOISTURE DEEPENS AHEAD OF THE APPROACHING COLD FRONT.
RADARS SHOWING ACTIVITY OVER SOUTHERN ONTARIO BUT THE AIR MASS IS
STILL SO DRY OVER THE REGION THAT IT WILL LIKELY BE A WHILE BEFORE
WE ACTUALLY SEE PCPN REACHING THE GROUND. THAT BEING SAID ONCE THE
RAIN DOES BEGIN THE UPPER DYNAMICS WILL BE SUCH THAT A PERIOD OF
MODERATE RAIN IS LIKELY ACROSS WESTERN NEW YORK BY MORNING AND
ACROSS THE EASTERN SECTIONS DURING THURSDAY MORNING...WITH
RAINFALL TOTALS GENERALLY AROUND A HALF INCH.
A COLD FRONT WILL CROSS THE AREA ON THURSDAY. THE SHOWERS WILL
THUS QUICKLY TAPER OFF FROM WEST TO EAST DURING THE COURSE OF THE
AFTERNOON.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
THE LONGWAVE PATTERN THAT WE WILL BE IN DURING THE NEXT WEEK TO TEN
DAYS IS ONE THAT SNOW LOVERS DREAM OF HAVING DURING THE WINTER
MONTHS...BUT ALAS...THEY WILL HAVE TO BE CONTENT WITH COMFORTABLY
COOL LATE SUMMER CONDITIONS. A DEEP TROUGH WILL BE RE-ESTABLISHED
ACROSS EASTERN CANADA AND THE GREAT LAKES REGION AT THE START OF
THIS PERIOD...WITH ADDITIONAL SHORTWAVE ENERGY DIVING INTO ITS BASE
AND THE BUILDING OF A GREENLAND BLOCK INSURING THAT THE HIGH
AMPLITUDE BLOCKING PATTERN WILL BE ANCHORED IN PLACE FOR SOME TIME
TO COME. THIS GENERAL LONGWAVE PATTERN IS STRONGLY SUPPORTED BY ALL
MEDIUM RANGE ENSEMBLE PACKAGES AS WELL AS CPC FORECASTS OF
HEMISPHERIC PROCESSES...LIKE THE NAO AND PNA. MORE ON THIS IN THE
LONG RANGE DISCUSSION BELOW. NOW FOCUSING IN ON THE DETAILS...
A COLD FRONT WILL MARCH ACROSS OUR FORECAST AREA ON THURSDAY...
WITH WIDESPREAD SHOWERS AND POSSIBLY A FEW EMBEDDED THUNDERSTORMS
EXPECTED AS A RESULT. THE GUIDANCE PACKAGES HAVE BEEN DEPICTING A
PROGRESSIVELY EARLIER ONSET OF PCPN FOR THE PAST SEVERAL RUNS...AND
IT SEEMS AS IF THIS IS TIED DIRECTLY TO THE SPEED AND PLACEMENT OF
THE FAVORABLE UPPER LEVEL LIFT SUPPLIED BY A 100KT H25 JET OVER
WESTERN QUEBEC. A 3 TO 5 HOUR PERIOD OF SHOWERS WILL BE ASSOCIATED
WITH THE LIFT FOUND WITHIN THE RR ENTRANCE REGION OF THIS JET...
WITH LINGERING SHOWERS FOUND BACK IN THE VCNTY OF THE LOW LEVEL
FORCING NEAR THE FRONT. THIS WILL BOIL DOWN TO THE BULK OF THE
SHOWERS COMING DURING THE MORNING HOURS FOR THE WRN COUNTIES...AND
DURING THE MIDDAY FOR SITES EAST OF LK ONTARIO. THE SHOWERS WILL
THUS QUICKLY TAPER OFF FROM WEST TO EAST DURING THE COURSE OF THE
AFTERNOON. HAVE RAISED POPS TO 90 REGIONWIDE WITH BASIN AVERAGE QPF
RANGING FROM A QUARTER TO A HALF INCH.
BY THURSDAY EVENING...THE PLUME OF DEEP MOISTURE AHEAD OF THE
FRONT WILL BE RACING ACROSS NEW ENGLAND WHILE THE ACTUAL SFC FRONT
WILL ONLY BE SLOWLY MAKING ITS WAY ACROSS THE EASTERN LAKE ONTARIO
REGION. THIS WILL KEEP THE LIKELIHOOD FOR SOME SHOWERS OVER THE
EASTERN FINGER LAKES AND FOR SITES EAST OF LK ONTARIO...WITH JUST
SPOTTY LIGHT SHOWERS POSSIBLE UNDER A PASSING SHORTWAVE ACROSS THE
WRN COUNTIES. THE TREND WILL DEFINTIELY BE TOWARDS DRIER WEATHER
THOUGH AS LOW LEVEL RIDGING WILL BUILD EAST FROM LOWER MICHIGAN AND
THE OHIO VALLEY.
ANOTHER ISSUE TO KEEP AN EYE ON WILL BE MARGINALLY FAVORABLE
CONDITIONS FOR NUISANCE LAKE EFFECT DURING THE WEE HOURS OF
FRIDAY MORNING. H85 TEMPS ARE FORECAST TO DROP TO AROUND 10C BY
DAYBREAK...AND WITH LK SFC TEMPS IN THE VCNTY OF 22C...THAT WOULD
ONLY SUPPORT WEAK INSTABILITY. THERE WILL ALSO BE LIMITED SYNOPTIC
MOISTURE TO WORK WITH...SO WILL CONTINUE SLGT CHC POPS EAST OF LK
ERIE AND LOW CHC POPS EAST OF LK ONTARIO FOR ANY MINOR LAKE
RESPONSE.
ON FRIDAY AND FRIDAY NIGHT...A SERIES OF WEAK SHORT WAVES WILL
ROTATE THROUGH THE BASE OF THE UPPER LEVEL TROUGH THAT WILL BE
FIRMLY ESTABLISHED OVER THE GREAT LAKES. WHILE THE VAST MAJORITY OF
THIS 24 HOUR PERIOD SHOULD BE RAIN FREE...SCATTERED LIGHT SHOWERS
WILL BE POSSIBLE. THE COMBINATION OF LATE SUMMER HEATING DURING THE
MIDDAY/AFTERNOON WILL COMBINE WITH A SEASONABLY COOL AIRMASS TO
GENERATE LOW LEVEL LAPSE RATES OF 9-10 DEG C/KM...AND THIS ALONG
WITH THE FORCING FROM THE AFOREMENTIONED SHORTWAVE SHOULD BE ENOUGH
TO SUPPORT CHC POPS THROUGH THE EVENING HOURS. THE OVERNIGHT SHOULD
LARGELY BE RAIN FREE...WITH ONLY CHC POPS EAST OF LK ONTARIO FOR
SOME LAKE EFFECT. TEMPS FRIDAY WILL AVERAGE ABOUT 5 DEG F BELOW
NORMAL WITH AFTERNOON HIGHS GENERALLY IN THE MID 70S.
SATURDAY SHOULD BE A FAIRLY NICE DAY...ALBEIT IT SEASONABLY COOL AS
SFC HIGH PRESSURE CENTERED OVER THE CANADIAN PRAIRIES WILL BUILD
SOUTHEAST ACROSS ALL OF THE GREAT LAKES. THIS SHOULD ENCOURAGE
PARTIAL SUNSHINE ACROSS THE REGION WITH H85 TEMPS HOLDING MAX TEMPS
IN THE LOW TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
ALL OF THE THE MEDIUM RANGE ENSEMBLES REMAIN IN STRONG AGREEMENT
THAT THE DEEP...UPPER LEVEL TROUGH WILL HOLD IN PLACE ACROSS EASTERN
NORTH AMERICA THROUGH MUCH IF NOT ALL OF NEXT WEEK. THIS SCENARIO
WILL GUARANTEE THAT WE WILL CONTINUE TO EXPERIENCE BELOW NORMAL
TEMPERATURES...ALTHOUGH NOT ANOMALOUSLY SO AS MERCURY LEVELS WILL
GENERALLY AVERAGING 3-5 DEG F BELOW NORMAL.
IN TERMS OF PCPN...THE BULK OF THIS TIME PERIOD WILL BE RAINFREE.
BESIDES THE LOW CHC FOR NUISANCE LAKE SHOWERS SOUTHEAST OF LK
ONTARIO...CANADIAN HIGH PRESSURE BUILDING ACROSS THE LOWER GREAT
SHOULD PROVIDE THE REGION WITH DRY WEATHER SUNDAY AND MONDAY. THE
ECMWF HAS BECOME THE OUTLIER ON SUNDAY IN THAT IT SUGGESTS THAT A
VIGOROUS SHORTWAVE WILL GENERATE SOME SHOWERS...BUT THIS IS A NEW
SOLUTION AND ONE THAT IS NOT SUPPORTED BY OTHER PACKAGES.
THE POTENTIAL FOR A FAIRLY POTENT SHORTWAVE AND ASSOCIATED SFC WAVE
TO PASS THROUGH THE REGION ON TUESDAY WILL NECESSITATE THE
INTRODUCTION OF CHC POPS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR CONDS PREVAIL ACROSS THE REGION AND WILL SO THROUGH THE EARLY
EVENING. CLOUDS WILL BECOME OVERCAST DURING THE EVENING HOURS WITH
CIGS LOWERING TO MVFR BEFORE DAYBREAK ACROSS FINGER LAKES AND
WEST... AND CONTINUING TO LOWER ACROSS THE EASTERN SECTIONS
THURSDAY MORNING. SHOWERS AND SCATTERED THUNDERSTORMS WILL
OVERSPREAD FROM WEST TO EAST MAINLY FROM MIDNIGHT ONWARD.
FOLLOWING FROPA...CONDS WILL THEN IMPROVE TO VFR FROM WEST TO EAST
ON THURSDAY.
OUTLOOK...
FRIDAY AND SATURDAY...MAINLY VFR WITH A SMALL CHANCE OF SHOWERS.
SUNDAY...VFR.
&&
.MARINE...
A RELATIVELY WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE ACROSS THE
LOWER LAKES TONIGHT. AFTER A FRONT CROSSES THE LAKES ON
THURSDAY...THE WINDS WILL SWITCH TO THE SOUTHWEST AND PICK UP A
BIT...BUT CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA. MORE IMPORTANTLY...THE FRONT WILL BRING A GOOD
CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS TONIGHT AND
THURSDAY...WITH LOCAL INCREASES IN WIND AND WAVES POSSIBLE.
THE PRESSURE GRADIENT BETWEEN BETWEEN A SURFACE HIGH OVER THE MIDDLE
ATLANTIC STATES AND LOW PRESSURE PUSHING ACROSS HUDSON BAY WILL
CAUSE WESTERLY WINDS TO PICK UP A LITTLE MORE ON FRIDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LEVAN
NEAR TERM...LEVAN
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...LEVAN
MARINE...LEVAN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1208 PM CDT WED JUL 31 2013
.UPDATE...
ISSUED AT 1208 PM CDT WED JUL 31 2013
LATEST VISIBLE IMAGERY SHOWS SCATTERED CUMULUS CLOUDS EMBEDDED WITHIN
THE NORTHWEST FLOW...WITH AN ISOLATED AREA OF BROKEN CLOUDS SEEN NEAR
THE BISMARCK/MANDAN AREA. THE FORECAST REMAINS ON TRACK THIS AFTERNOON
WITH MOSTLY SUNNY SKIES. ONLY MINOR UPDATES TO HOURLY TEMPERATURES.
UPDATE ISSUED AT 901 AM CDT WED JUL 31 2013
LATEST VISIBLE SATELLITE IMAGERY SHOWS A SCT TO BKN CUMULUS FIELD
FROM NEAR CROSBY TO STANLEY AND INTO GARRISON...ASSOCIATED WITH A
COLD POCKET IN THE H85-H7 LAYER. THIS WILL CONTINUE TO MOVE
SOUTHEAST INTO THE JAMES RIVER VALLEY AS THE MID AND UPPER LEVEL
WINDS WINDS ARE NORTHWEST. WATER VAPOR IMAGERY SHOWS THE NEXT
SHORTWAVE NOW OVER NORTHWEST SASKATCHEWAN MOVING SOUTHEAST WITH
TIME. IT IS FORECAST TO SHIFT NEAR SASKATOON AROUND 00Z
THURSDAY...WITH SOME SPOTTY SHOWERS REACHING AS FAR SOUTH AS
BRANDON MANITOBA. AN ISOLATED SHOWER COULD CLIP THE TURTLE
MOUNTAINS EARLY THIS EVENING BUT NOT MUCH MORE THAN THAT.
MAIN ADJUSTMENT TO THE GRIDS THIS MORNING IS TO INCREASE SKY
COVER TO ACCOUNT FOR THE CUMULUS DECK...AS SOUNDINGS AND CROSS
SECTIONS SHOW WE WILL REMAIN NEARLY DRY ADIABATIC INTO THE
SHALLOW MOIST/COLDER H85-H7 LAYER. MIXING INTO DRIER AIR ALOFT
THIS AFTERNOON WILL LIMIT COVERAGE AND VERTICAL EXTENT.
UPDATE ISSUED AT 639 AM CDT WED JUL 31 2013
UPDATED THE FORECAST TO REMOVE FIRST PERIOD POPS FROM THE
SOUTHWESTERN ZONES BASED ON CURRENT RADAR OBS/TRENDS. FOR THE
SOUTHEASTERN ZONES...CHANGED PRECIPITATION WORDING TO COVERAGE
TERMINOLOGY TO BETTER REFLECT THE CURRENT CONDITIONS. THE
CONVECTIVE ACTIVITY SHOULD BE OUT OF THE SOUTHERN JAMES RIVER
BASIN IN THE NEXT FEW HOURS.
FURTHERMORE...ADDED PATCHY FOG WORDING AROUND DICKINSON GIVEN THE
LIGHT WINDS AND REDUCED VISIBILITIES HAVING BEEN REPORTED THERE FOR
ABOUT AN HOUR NOW. THINK VISIBILITIES WILL IMPROVE IN THE NEXT
HOUR OR SO WHEN VERTICAL MIXING COMMENCES.
THE REMAINING WEATHER ELEMENTS ARE IN GOOD SHAPE. THE UPDATED
GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT WED JUL 31 2013
MAIN FORECAST CONCERN WILL BE SHOWER AND THUNDERSTORM COVERAGE IN
THE NEAR TERM. LATEST RADAR AT 0818 UTC SHOWS THAT THE SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY GRADUALLY SHIFTING TO THE SOUTH
AND EAST. THUNDERSTORMS ARE EXPECTED TO REMAIN SUB-SEVERE...PER THE
08 UTC SPC MESOANALYSIS...AS ML AND MU CAPE ARE MINIMAL EVEN
THOUGH 50 KTS OF 0-6 KM SHEAR IS PRESENT. THE 06 UTC HRRR AND 07
UTC RAP BOTH CONTINUE THE TREND OF MOVING SHOWER AND THUNDERSTORM
ACTIVITY TO THE SOUTH AND EAST...WITH ALL ACTIVITY COMING TO AN
END ACROSS THE SOUTH CENTRAL BETWEEN 13 TO 15 UTC.
FOR TODAY AND TONIGHT...NORTHWEST FLOW WILL PREVAIL
ALLOWING FOR DRY AND QUIET WEATHER TO TAKE HOLD AS HIGH PRESSURE
MOVES OVER THE REGION. COOLER THAN TEMPERATURES ARE EXPECTED WITH
HIGHS GENERALLY IN THE 70S AND LOWS IN THE UPPER 40S TO MID 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CDT WED JUL 31 2013
THE MEDIUM RANGE MODELS ARE STILL IN FAIRLY GOOD AGREEMENT WITH
PERSISTENT NORTHWESTERLY FLOW ALOFT OVER WESTERN AND CENTRAL NORTH
DAKOTA THROUGH THE PERIOD. THIS PATTERN WILL MAINTAIN BELOW NORMAL
TEMPERATURES ACROSS THE STATE THROUGH THE FIRST WEEK IN AUGUST.
NORTHWEST FLOW IS ALSO NOTORIOUS FOR LOW PREDICTABILITY WAVES
YIELDING THE POTENTIAL FOR ISOLATED CONVECTION NEARLY EVERY DAY.
HOWEVER...THE BEST CHANCES FOR WIDESPREAD PRECIPITATION LOOK TO BE
SATURDAY THROUGH SUNDAY AS THE PACIFIC NORTHWEST UPPER LOW
PROPAGATES ALONG THE CREST OF THE RIDGE INTO THE NORTHERN PLAINS.
THUNDERSTORMS SHOULD REMAIN BELOW SEVERE LIMITS GIVEN THE WEAK
INSTABILITY PROGGED DURING THE WEEKEND. HOWEVER...WILL CONTINUE TO
MONITOR TRENDS AND ADJUST THE FORECAST AS NEEDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1208 PM CDT WED JUL 31 2013
VFR CIGS/VSBYS NEXT 24HR. SCT CUMULUS CLOUDS WILL CONTINUE THROUGH
SUNSET WITH CLEARING SKIES COMMENCING THEREAFTER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...LTH
LONG TERM...TM
AVIATION...KS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
350 PM EDT WED JUL 31 2013
.SYNOPSIS...
A WEAK COLD FRONT CROSSES LATE TONIGHT AND EARLY THURSDAY. HIGH
PRESSURE PASSES THURSDAY NIGHT/FRIDAY MORNING. A COLD FRONT CROSSES
THIS WEEKEND...FOLLOWED BY BELOW NORMAL TEMPERATURES EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
DISTURBANCE MOVING THRU CWA WITH MAINLY SCT -SHRA AND EVEN SOME
-DZ ABOUT THE AREA. WEAKENING VORT MAX HANGING OUT ACROSS SE OH CO
WITH LOBE APPENDAGE MOVING NE INTO N WV SERVING AS MAIN FOCUS FOR
LIFT. RUC AND HRRR SEEMS TO HAVE A MUCH BETTER HANDLE ON THINGS VS
OTHER MDLS AND HAVE USED THESE AS GUIDANCE. OTHERWISE LOOKING AT
AN ABUNDANCE OF LLVL MOISTURE REMAINDER OF AFTN.
FRONT POISED TO MOVE THRU LATE TONIGHT INTO EARLY THU MORNING WITH
A BAND OF SHRA WITH IT. THERE COULD BE AN AREA OF -RA OR DZ ALONG
AND E OF I79 TONIGHT BEFORE AFOREMENTIONED SHRA ARRIVE WITH
IMPRESSIVE DRYING SHOWING UP IN MID LVLS. THINK LOW STRATUS AND
FG WILL SETUP REGARDLESS THIS EVE...TRYING TO LIFT SOME AS FRONTAL
SHRA MOVE IN PREDAWN.
ALL OF THIS PUSHES E ON THU WITH AMPLIFYING UPR TROF ACROSS OH
VALLEY. HOWEVER...LLVL MOISTURE WILL BE VERY SLOW TO GIVE UP THE
GHOST. EVEN THOUGH LOW STRATUS LIFTS BY MIDDAY...SUSPECT THIS WILL
GIVE WAY TO AN ABUNDANCE OF CU GIVEN H85 MOISTURE UNDERNEATH A
DEVELOPING STOUT INVERSION ARND H7. AS FOR POPS DRY THINGS OUT FOR
MOST PART. DID LEAVE SOME LOW POPS FOR A FEW EARLY AFTN DEVELOPMENT
ACROSS THE MTNS.
FOR TEMPS...INHERITED NUMBERS LOOKED GOOD TONIGHT. ELECTED TO GO
CLOSER TO COOLER MET ON THU WITH EXPECTATION THAT EXTENT OF CLDS
HOLDS NUMBERS DOWN A BIT.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
A FEW OF THE MESO MODELS ARE SHOWING SOME LINGERING SHOWERS BEHIND
THE COLD FRONT THURSDAY NIGHT. DUE TO THE TIME OF DAY AND DRY AIR
PUSH...DO NOT THINK THAT THIS IS REALISTIC. WILL LEAVE DRY FOR NOW.
HIGH PRESSURE THEN PROVIDES A BRIEF PERIOD OF DRY WEATHER FRIDAY
MORNING. ALL MODELS ARE SHOWING SOME MOISTURE PUSHING BACK IN LATE
FRIDAY...ALTHOUGH TIMING DIFFERENCES EXIST. WILL INCLUDE A CHANCE OF
SHOWERS...AND POSSIBLY THUNDERSTORMS...BUT NOT BE TOO DEFINITIVE. WILL
INCREASE POPS INTO SATURDAY AS FRONT APPROACHES AND MOISTURE
DEEPENS. FRONT THEN PUSHES THROUGH LATE SATURDAY/SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
LOTS OF MODEL DIFFERENCES IN HOW FAR SOUTH THE FRONT AND MOISTURE
PUSH FOR THE END OF THE WEEKEND AND BEGINNING OF NEXT WEEK. USED A
BLEND OF THE ECMWF MEAN AND THE GEFS...WHICH WOULD PUT THE FRONT
JUST SOUTH OF THE FORECAST AREA. WITH SOME WAVES POSSIBLE ALONG THE
FRONT...SOME PRECIPITATION COULD MAKE IT INTO THE FORECAST
AREA...WITH THE BEST CHANCES IN THE SOUTH.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
18Z WEDNESDAY THRU 18Z THURSDAY...
UPR LVL DISTURBANCE SLOWLY PUSH NE THRU AREA THIS AFTN WITH SCT
SHRA AND EVEN PATCHY DZ. THINK KCRW...KBKW...KEKN STAND BEST CHC
OF SEEING PCPN AND THUS HAVE THOSE TERMINALS IN MVFR VSBY IN SHRA
THIS AFTN. OTHERWISE GENERALLY LOOKING AT MVFR CIGS SAVE ACROSS SE
OH AND N WV LOWLANDS. THESE WILL LWR TONIGHT INTO MAINLY IFR CIGS
WITH MVFR ACROSS SE OH/N LOWLANDS. HAVE SOME IFR VSBY COMBO FG
WHERE IT HAS RAINED. KEKN MAY SEE CIGS LWR INTO LIFR.
SLOW MOVING COLD FRONT APPROACHES AFTER 10Z WITH SOME SHRA. THESE
SHOULD ALLOW CIGS AND VSBY TO IMPROVE BY DAWN. FRONT MOVES E OF
AREA THU MORNING. LLVL MOISTURE WILL LINGER THOUGH...BENEATH A
DEVELOPING INVERSION...WHICH WILL DELAY IMPROVEMENT OF CIGS. THINK
LOW STRATUS LIFTS INTO MVFR ABUNDANCE OF CU BY AFTN. ANY LINGERING
SHRA ACROSS THE MTNS SHOULD END IN AFTN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DEVELOPMENT OF LOW STRATUS/FOG AFTER 00Z MAY
VARY FROM CURRENT FORECAST. TIMING OF FRONT AND SHRA TONIGHT 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 H H M M M M M M M H H H
HTS CONSISTENCY M M M M M M H H H H H H
BKW CONSISTENCY M M M M M M H H H M M M
EKN CONSISTENCY H H M M M M M M M H H H
PKB CONSISTENCY H H H H H H H H H M M M
CKB CONSISTENCY H H H H H H H H H M M H
AFTER 18Z THURSDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS LATE FRIDAY THROUGH
SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...RPY
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
230 PM EDT WED JUL 31 2013
.SYNOPSIS...
A WEAK COLD FRONT CROSSES LATE TONIGHT AND EARLY THURSDAY. HIGH
PRESSURE PASSES FRIDAY MORNING. A COLD FRONT CROSSES THIS
WEEKEND...FOLLOWED BY HIGH PRESSURE SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY/...
DISTURBANCE MOVING THRU CWA WITH MAINLY SCT -SHRA AND EVEN SOME
-DZ ABOUT THE AREA. WEAKENING VORT MAX HANGING OUT ACROSS SE OH CO
WITH LOBE APPENDAGE MOVING NE INTO N WV SERVING AS MAIN FOCUS FOR
LIFT. RUC AND HRRR SEEMS TO HAVE A MUCH BETTER HANDLE ON THINGS VS
OTHER MDLS AND HAVE USED THESE AS GUIDANCE. OTHERWISE LOOKING AT
AN ABUNDANCE OF LLVL MOISTURE REMAINDER OF AFTN.
FRONT POISED TO MOVE THRU LATE TONIGHT INTO EARLY THU MORNING WITH
A BAND OF SHRA WITH IT. THERE COULD BE AN AREA OF -RA OR DZ ALONG
AND E OF I79 TONIGHT BEFORE AFOREMENTIONED SHRA ARRIVE WITH
IMPRESSIVE DRYING SHOWING UP IN MID LVLS. THINK LOW STRATUS AND
FG WILL SETUP REGARDLESS THIS EVE...TRYING TO LIFT SOME AS FRONTAL
SHRA MOVE IN PREDAWN.
ALL OF THIS PUSHES E ON THU WITH AMPLIFYING UPR TROF ACROSS OH
VALLEY. HOWEVER...LLVL MOISTURE WILL BE VERY SLOW TO GIVE UP THE
GHOST. EVEN THOUGH LOW STRATUS LIFTS BY MIDDAY...SUSPECT THIS WILL
GIVE WAY TO AN ABUNDANCE OF CU GIVEN H85 MOISTURE UNDERNEATH A
DEVELOPING STOUT INVERSION ARND H7. AS FOR POPS DRY THINGS OUT FOR
MOST PART. DID LEAVE SOME LOW POPS FOR A FEW EARLY AFTN DEVELOPMENT
ACROSS THE MTNS.
FOR TEMPS...INHERITED NUMBERS LOOKED GOOD TONIGHT. ELECTED TO GO
CLOSER TO COOLER MET ON THU WITH EXPECTATION THAT EXTENT OF CLDS
HOLDS NUMBERS DOWN A BIT.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
SHORT WAVE TROUGH EXITS FIRST THING IN THE MORNING...TAKING THE DEEP
LAYER MOISTURE AND THE LAST OF THE SIGNIFICANT RAINFALL WITH IT. A
SECOND SHORT WAVE TROUGH SETTLES INTO THE AREA LATE THU AFTER A WEAK
COLD FRONT CROSSES...LITTLE FORCING ASSOCIATED WITH EITHER AND NOT A
LOT OF MOISTURE TO WORK WITH OUTSIDE THE LOW LEVELS. WILL LIKELY
SEE A MURKY SOUGHT OF DAY WITH STRATUS AND FOG IN THE MORNING GIVING
WAY TO SOME SUNSHINE IN THE AFTERNOON ALONG WITH LOW COVERAGE POP UP
SHOWERS / THUNDERSTORMS.
HIGH PRESSURE PASSES S OF THE AREA THU NT INTO FRI..LIKELY LEADING
TO DENSE RIVER VALLEY FOG EARLY FRI MORNING. ANOTHER SHORT WAVE
TROUGH IN NEARLY ZONAL FLOW ALOFT ARRIVES FRI NT IN THE WORLD OF THE
NAM...AND LOOKS SIMILAR TO THE ONE ARRIVING IN THE NEAR TERM. OTHER
MODELS ARE SLOWER AND / OR FLATTER WITH THIS FEATURE. FOR NOW DID
EXTEND THE EXISTING SMALL CHANCE FOR PRECIPITATION SAT BACK INTO FRI
NT.
TEMPERATURES LOOKED GOOD FOR THU AND THU NT. USED ADJMET TO RAISE
HIGHS A BIT FRI AND CONSALL FOR SAME ON LOWS FRI NT.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
GENERALLY FOLLOWED WPC THINKING WITH SOME TWEAKS. HIGH PRESSURE
SHOULD PREVAIL AT THE BEGINNING OF THE PERIOD. ANOTHER COLD FRONT
WILL THEN PUSH SLOWLY SOUTHEAST WITH A CHANCE OF SHOWERS AND
STORMS SATURDAY INTO SUNDAY NIGHT. ANOTHER SYSTEM SHOULD BRING
MORE PRECIP CHANCES FOR EARLY NEXT WEEK.
TEMPERATURES SHOULD GENERALLY REMAIN SLIGHTLY BELOW NORMAL.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
18Z WEDNESDAY THRU 18Z THURSDAY...
UPR LVL DISTURBANCE SLOWLY PUSH NE THRU AREA THIS AFTN WITH SCT
SHRA AND EVEN PATCHY DZ. THINK KCRW...KBKW...KEKN STAND BEST CHC
OF SEEING PCPN AND THUS HAVE THOSE TERMINALS IN MVFR VSBY IN SHRA
THIS AFTN. OTHERWISE GENERALLY LOOKING AT MVFR CIGS SAVE ACROSS SE
OH AND N WV LOWLANDS. THESE WILL LWR TONIGHT INTO MAINLY IFR CIGS
WITH MVFR ACROSS SE OH/N LOWLANDS. HAVE SOME IFR VSBY COMBO FG
WHERE IT HAS RAINED. KEKN MAY SEE CIGS LWR INTO LIFR.
SLOW MOVING COLD FRONT APPROACHES AFTER 10Z WITH SOME SHRA. THESE
SHOULD ALLOW CIGS AND VSBY TO IMPROVE BY DAWN. FRONT MOVES E OF
AREA THU MORNING. LLVL MOISTURE WILL LINGER THOUGH...BENEATH A
DEVELOPING INVERSION...WHICH WILL DELAY IMPROVEMENT OF CIGS. THINK
LOW STRATUS LIFTS INTO MVFR ABUNDANCE OF CU BY AFTN. ANY LINGERING
SHRA ACROSS THE MTNS SHOULD END IN AFTN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DEVELOPMENT OF LOW STRATUS/FOG AFTER 00Z MAY
VARY FROM CURRENT FORECAST. TIMING OF FRONT AND SHRA TONIGHT 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 H H M M M M M M M H H H
HTS CONSISTENCY M M M M M M H H H H H H
BKW CONSISTENCY M M M M M M H H H M M M
EKN CONSISTENCY H H M M M M M M M H H H
PKB CONSISTENCY H H H H H H H H H M M M
CKB CONSISTENCY H H H H H H H H H M M H
AFTER 18Z THURSDAY...
POSSIBLE IFR IN POST-RAIN STRATUS AND FOG INTO THURSDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...TRM
LONG TERM...JSH
AVIATION...30
AREA FORECAST DISCUSSION...CORRECTION
NWS PENDLETON OR
1244 PM PDT WED JUL 31 2013
CORRECTION APPLIED DUE TO DISSEMINATION ISSUES
.SHORT TERM...UPDATE...AN UPPER LEVEL LOW, WITH EMBEDDED SHORTWAVE
DISTURBANCES, IS OFF THE PACIFIC COASTLINE THIS MORNING ADVECTING
MOISTURE INTO OUR REGION THIS MORNING. RADAR INDICATES THAT SHOWERS
HAVE DEVELOPED OVER THE FOOTHILLS OF THE BLUE MOUNTAINS AND THE JOHN
DAY HIGHLANDS, WHILE THE CASCADES HAVE NO RETURNS SHOWING UP. HAVE
UPDATED THE POP GRIDS THIS MORNING TO INDICATE AN ISOLATED CHANCE OF
SHOWERS FOR MAINLY THE JOHN DAY HIGHLANDS AND THE BLUE MOUNTAINS.
ALSO, AS A RESULT OF CLOUDINESS FROM MORNING ACTIVITY, HAVE TRIMMED
BACK THE MAX TEMPERATURES FOR MOST LOCATIONS.
WATER VAPOR IS SHOWING A SHORTWAVE IMPULSE NEAR THE CALIFORNIA AND
OREGON BORDER, MOVING NORTHEAST TOWARDS OUR CWA. IT IS ANTICIPATED
THAT THIS IMPULSE WILL ARRIVE IN OUR AREA BY THIS AFTERNOON,
PROVIDING A FOCUSING MECHANISM AND LIFT FOR INCREASED THUNDERSTORM
ACTIVITY LATER TODAY. MARGINAL INSTABILITY OF APPROXIMATELY 500 J
PER KG OF ELEVATED CAPE, A STRONG INVERTED V PROFILE IN FORECASTED
SOUNDINGS, AND NEAR 50 KTS OF SHEAR ARE CONDUCIVE FACTORS FOR STRONG
THUNDERSTORMS CAPABLE OF PRODUCING STRONG WINDS AND EVEN SOME SMALL
HAIL. LATEST HRRR RUNS AND HI-RES WRF ENSEMBLE INDICATE THAT THE
STORMS WILL START MAINLY OVER THE CENTRAL AND EASTERN OREGON
HIGHLANDS, THEN PROPAGATE INTO THE LOWER COLUMBIA BASIN LATER THIS
EVENING. BIEDA/SOLOMON
.LONG TERM...PREVIOUS DISCUSSION...FRIDAY NIGHT THROUGH
WEDNESDAY...AN UPPER LOW PRESSURE SYSTEM CENTERED OVER EAST CENTRAL
WASHINGTON FRIDAY NIGHT WILL MOVE OFF TO THE NORTHEAST ON SATURDAY.
IN ITS WAKE THERE WILL BE A REMNANT UPPER TROUGH OVER THE PACIFIC
NORTHWEST AND THE FORECAST AREA. THIS WILL KEEP UNSETTLED AND COOL
CONDITIONS OVER THE FORECAST AREA...ESPECIALLY IN THE NORTHERN
PORTIONS OF THE CWA ON SATURDAY. THIS UNSETTLED WEATHER WILL
DECREASE SUNDAY AND MONDAY AS AN UPPER RIDGE BUILDS OVER THE REGION.
THE UPPER RIDGE WILL BE DEVELOPING IN RESPONSE TO A NEW UPPER LOW
THAT WILL DEVELOP OFF THE NORTHERN CALIFORNIA COAST. THE RESULT WILL
BE MORE DRY CONDITIONS AND A WARMING TREND FOR EARLY NEXT WEEK. THE
LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS SCENARIO
THROUGH MONDAY AND TUESDAY THOUGH THERE WILL BE SOME DIFFERENCES TO
EXACTLY WHERE THE UPPER LOW WILL BE CENTERED OFF THE COAST. ON
WEDNESDAY THE MODEL DIFFERENCES BECOME GREATER BUT STILL SHOW A
RIDGE OVER THE CWA WITH AN UPPER LOW OFF THE CALIFORNIA COAST. 88
&&
.AVIATION...18Z TAFS...A LOW PRESSURE SYSTEM WILL BRING AN INCREASE
IN HIGH AND MID LEVEL CLOUDS OVER THE AREA TODAY AND THROUGH
TOMORROW. ISOLATED AND SCATTERED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WILL OCCUR ACROSS THE REGION. KDLS...KRDM AND KBDN
WILL BE AFFECTED FIRST THIS AFTERNOON AND THEN SPREAD TO THE REST OF
THE TAF SITES THIS EVENING. MAY SEE BRIEF MVFR CONDITIONS IN RAIN
DIRECTLY UNDER A THUNDERSTORM BUT OTHERWISE VFR CONDITIONS WILL
PREVAIL. CAN NOT PINPOINT EXACTLY WHEN A THUNDERSTORM WILL PASS OVER
A TAF SITE...AND THEREFORE ONLY INDICATED THE POTENTIAL WITH A MID
LEVEL CLOUD LAYER DURING THE AFTERNOON AND EVENING...WHEN THE BEST
THUNDERSTORM POTENTIAL WILL BE. EXPECT WINDS TO REMAIN LESS THAN 15
KTS THROUGH TONIGHT...BUT CAN EXPECT GUSTY WINDS NEAR THUNDERSTORMS.
AREAS OF SMOKE WILL CONTINUE DUE TO AREA WILDFIRES. DMH
&&
.FIRE WEATHER...A LOW PRESSURE SYSTEM WILL BRING THUNDERSTORMS TO
THE FORECAST AREA TODAY. THE FIRST DISTURBANCE IS ROTATING AROUND
THE LOW AND WILL ENTER OUR AREA THIS AFTERNOON. A RED FLAG WARNING
ARE FOR ALL FIRE WEATHER ZONES THROUGH THURSDAY EVENING. WHILE
THUNDERSTORMS WILL START OUT WITH LIGHT PRECIPITATION...EXPECT THEM
TO BECOME WETTER TODAY ALONG THE CASCADES AND THEN TONIGHT INTO
TOMORROW FOR THE REST OF THE REGION. THUNDERSTORMS WILL CONTINUE
TOMORROW AS THE LOW MOVES OVERHEAD. ALL RED FLAG WARNINGS WILL END
TOMORROW NIGHT AND EXPECT THUNDERSTORMS TO DECREASE IN COVERAGE
OVERNIGHT ON TOMORROW NIGHT AND INTO FRIDAY. THUNDERSTORMS ARE
EXPECTED TO HAVE THE POTENTIAL OF PRODUCING STRONG GUSTY WINDS.
SURFACE WINDS WILL ALSO INCREASE ON TOMORROW AS THE LOW MOVES
EASTWARD WITH LOCALLY BREEZY TO WINDY CONDITIONS ESPECIALLY IN THE
COLUMBIA BASIN AND NEAR THE CASCADE GAPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 81 60 83 58 / 20 30 40 30
ALW 84 64 86 62 / 20 30 30 40
PSC 87 64 88 64 / 10 30 30 40
YKM 86 63 86 62 / 20 30 30 30
HRI 85 62 87 63 / 20 30 30 30
ELN 83 61 84 62 / 20 30 40 40
RDM 84 52 76 45 / 30 30 60 20
LGD 80 57 78 54 / 20 30 60 50
GCD 82 57 76 53 / 30 30 60 30
DLS 87 63 80 61 / 30 30 30 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING FROM 8 PM THIS EVENING TO 11 PM PDT THURSDAY
ORZ044-050-508.
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THURSDAY
ORZ049-502-503-505>507.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY ORZ041-042-509.
WA...RED FLAG WARNING FROM 8 PM THIS EVENING TO 11 PM PDT THURSDAY
WAZ026>029.
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THURSDAY
WAZ030.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY WAZ024-520-521.
FIRE WEATHER WATCH FROM 8 PM PDT THIS EVENING THROUGH THURSDAY
EVENING WAZ026-027-520.
&&
THREAT INDEX
TODAY : YELLOW
THURSDAY : YELLOW
FRIDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
98/91/84/84
AREA FORECAST DISCUSSION...CORRECTED
NWS PENDLETON OR
931 AM PDT WED JUL 31 2013
CORRECTION IN SHORT TERM DISCUSSION
.SHORT TERM...UPDATE...AN UPPER LEVEL LOW, WITH EMBEDDED SHORTWAVE
DISTURBANCES, IS OFF THE PACIFIC COASTLINE THIS MORNING ADVECTING
MOISTURE INTO OUR REGION THIS MORNING. RADAR INDICATES THAT SHOWERS
HAVE DEVELOPED OVER THE FOOTHILLS OF THE BLUE MOUNTAINS AND THE JOHN
DAY HIGHLANDS, WHILE THE CASCADES HAVE NO RETURNS SHOWING UP. HAVE
UPDATED THE POP GRIDS THIS MORNING TO INDICATE AN ISOLATED CHANCE OF
SHOWERS FOR MAINLY THE JOHN DAY HIGHLANDS AND THE BLUE MOUNTAINS.
ALSO, AS A RESULT OF CLOUDINESS FROM MORNING ACTIVITY, HAVE TRIMMED
BACK THE MAX TEMPERATURES FOR MOST LOCATIONS.
WATER VAPOR IS SHOWING A SHORTWAVE IMPULSE NEAR THE CALIFORNIA AND
OREGON BORDER, MOVING NORTHEAST TOWARDS OUR CWA. IT IS ANTICIPATED
THAT THIS IMPULSE WILL ARRIVE IN OUR AREA BY THIS AFTERNOON,
PROVIDING A FOCUSING MECHANISM AND LIFT FOR INCREASED THUNDERSTORM
ACTIVITY LATER TODAY. MARGINAL INSTABILITY OF APPROXIMATELY 500 J
PER KG OF ELEVATED CAPE, A STRONG INVERTED V PROFILE IN FORECASTED
SOUNDINGS, AND NEAR 50 KTS OF SHEAR ARE CONDUCIVE FACTORS FOR STRONG
THUNDERSTORMS CAPABLE OF PRODUCING STRONG WINDS AND EVEN SOME SMALL
HAIL. LATEST HRRR RUNS AND HI-RES WRF ENSEMBLE INDICATE THAT THE
STORMS WILL START MAINLY OVER THE CENTRAL AND EASTERN OREGON
HIGHLANDS, THEN PROPAGATE INTO THE LOWER COLUMBIA BASIN LATER THIS
EVENING. BIEDA/SOLOMON
.LONG TERM...PREVIOUS DISCUSSION...FRIDAY NIGHT THROUGH
WEDNESDAY...AN UPPER LOW PRESSURE SYSTEM CENTERED OVER EAST CENTRAL
WASHINGTON FRIDAY NIGHT WILL MOVE OFF TO THE NORTHEAST ON SATURDAY.
IN ITS WAKE THERE WILL BE A REMNANT UPPER TROUGH OVER THE PACIFIC
NORTHWEST AND THE FORECAST AREA. THIS WILL KEEP UNSETTLED AND COOL
CONDITIONS OVER THE FORECAST AREA...ESPECIALLY IN THE NORTHERN
PORTIONS OF THE CWA ON SATURDAY. THIS UNSETTLED WEATHER WILL
DECREASE SUNDAY AND MONDAY AS AN UPPER RIDGE BUILDS OVER THE REGION.
THE UPPER RIDGE WILL BE DEVELOPING IN RESPONSE TO A NEW UPPER LOW
THAT WILL DEVELOP OFF THE NORTHERN CALIFORNIA COAST. THE RESULT WILL
BE MORE DRY CONDITIONS AND A WARMING TREND FOR EARLY NEXT WEEK. THE
LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS SCENARIO
THROUGH MONDAY AND TUESDAY THOUGH THERE WILL BE SOME DIFFERENCES TO
EXACTLY WHERE THE UPPER LOW WILL BE CENTERED OFF THE COAST. ON
WEDNESDAY THE MODEL DIFFERENCES BECOME GREATER BUT STILL SHOW A
RIDGE OVER THE CWA WITH AN UPPER LOW OFF THE CALIFORNIA COAST. 88
&&
.AVIATION...PREVIOUS DISCUSSION...12Z TAFS...VFR CONDITIONS WILL
PREVAIL. HOWEVER THERE WILL BE AN ABUNDANCE OF HIGH CLOUDS AND SOME
MID LEVEL CLOUDS AS WELL BETWEEN 100-120 AND FROM 200-250. THERE
WILL BE ISOLATED TO SCATTERED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS THAT WILL AFFECT KDLS...KRDM...KBDN AND KYKM TODAY.
THE THUNDERSTORM ACTIVITY WILL THEN SPREAD OVER THE REST OF THE AREA
BY THIS EVENING. MOST STORMS THAT DEVELOP WILL BE WEAK BUT THERE
COULD BE SOME TEMPORARY MVFR CONDITIONS DUE TO LOWERING VISIBILITY
IN THE IMMEDIATE VICINITY OF SHOWERS WITH THE STRONGER STORMS.
THUNDERSTORMS WILL BE HIGH BASED SO CIGS WILL STAY WELL ABOVE VFR
MINIMUMS AT ALL TAF SITES. WINDS WILL BE LIGHT AND GENERALLY 5 TO 15
KTS THROUGH TONIGHT. AREAS OF SMOKE WILL CONTINUE IN THE VICINITY OF
WILDFIRES. 88
&&
.FIRE WEATHER...A LOW PRESSURE SYSTEM WILL BRING THUNDERSTORMS TO
THE FORECAST AREA TODAY. THE FIRST DISTURBANCE IS ROTATING AROUND
THE LOW AND WILL ENTER OUR AREA THIS AFTERNOON. A RED FLAG WARNING
ARE FOR ALL FIRE WEATHER ZONES THROUGH THURSDAY EVENING. WHILE
THUNDERSTORMS WILL START OUT WITH LIGHT PRECIPITATION...EXPECT THEM
TO BECOME WETTER TODAY ALONG THE CASCADES AND THEN TONIGHT INTO
TOMORROW FOR THE REST OF THE REGION. THUNDERSTORMS WILL CONTINUE
TOMORROW AS THE LOW MOVES OVERHEAD. ALL RED FLAG WARNINGS WILL END
TOMORROW NIGHT AND EXPECT THUNDERSTORMS TO DECREASE IN COVERAGE
OVERNIGHT ON TOMORROW NIGHT AND INTO FRIDAY. THUNDERSTORMS ARE
EXPECTED TO HAVE THE POTENTIAL OF PRODUCING STRONG GUSTY WINDS.
SURFACE WINDS WILL ALSO INCREASE ON TOMORROW AS THE LOW MOVES
EASTWARD WITH LOCALLY BREEZY TO WINDY CONDITIONS ESPECIALLY IN THE
COLUMBIA BASIN AND NEAR THE CASCADE GAPS.
&&
.PREV DISCUSSION... /ISSUED 700 AM PDT WED JUL 31 2013/
SHORT TERM...TODAY THROUGH FRIDAY AFTERNOON...TROUGH OFFSHORE SETS
UP CONDITIONS FAVORABLE FOR THUNDERSTORMS FOR THE NEXT THREE DAYS.
STRONG VERTICAL WIND SHEAR TODAY MAY SUPPORT A FEW STRONG OR
MARGINALLY SEVERE STORMS BUT INSTABILITY IS ONLY MARGINAL TODAY. AS
SUCH A FEW STORMS TODAY AND THIS EVENING MAY BE CAPABLE OF PRODUCING
MARGINALLY SEVERE HAIL TO ONE INCH IN DIAMETER AND GUSTY WINDS.
THUNDERSTORMS WILL BEGIN OVER THE MOUNTAINS IN CENTRAL OREGON AND
THE SOUTHERN BLUE MOUNTAINS BY MID AFTERNOON TODAY. SOME STORMS MAY
MOVE NORTH INTO THE LOWER COLUMBIA BASIN AS WELL AS NORTH CENTRAL
OREGON IN THE EVENING.
A MID/UPPER LEVEL SHORT WAVE SWINGS EAST OF THE OREGON CASCADES
OVERNIGHT THUS SOME STRONG DYNAMIC LIFT, WHICH WILL TRIGGER ISOLATED
TO SCATTERED NOCTURNAL THUNDERSTORMS IN THE BLUE MOUNTAINS TOWARD
DAYBREAK THURSDAY MORNING WITH STORMS BEING TRIGGERED BY DYNAMIC
LIFT FOR THE DURATION OF THURSDAY. STORMS ON THURSDAY ARE NOT
EXPECTED TO BE SEVERE. ALTHOUGH THE ATMOSPHERE WILL BE MUCH MORE
UNSTABLE DURING THE DAYTIME ON THURSDAY, ONLY WEAK VERTICAL WIND
SHEAR IS EXPECTED SO THE THUNDERSTORMS THURSDAY SHOULD BE WEAKER
THAN STORMS TODAY.
THE FOCUS FOR THUNDERSTORMS SHIFTS TO NE OREGON AND SE WASHINGTON ON
FRIDAY AS THE UPPER LEVEL TROUGH SWINGS EAST OF THE CASCADES. POLAN
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 86 60 86 58 / 20 30 40 30
ALW 90 63 88 62 / 20 30 30 40
PSC 91 63 90 63 / 10 30 30 40
YKM 86 63 89 62 / 20 30 30 40
HRI 89 61 89 62 / 20 30 30 30
ELN 87 60 87 62 / 20 30 40 50
RDM 83 52 79 45 / 30 30 60 20
LGD 89 55 82 53 / 20 30 50 50
GCD 89 56 82 53 / 30 30 60 30
DLS 88 61 82 60 / 30 30 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING FROM 8 PM THIS EVENING TO 11 PM PDT THURSDAY
ORZ044-050-508.
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THURSDAY
ORZ049-502-503-505>507.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY ORZ041-042-509.
WA...RED FLAG WARNING FROM 8 PM THIS EVENING TO 11 PM PDT THURSDAY
WAZ026>029.
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THURSDAY
WAZ030.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY WAZ024-520-521.
FIRE WEATHER WATCH FROM 8 PM PDT THIS EVENING THROUGH THURSDAY
EVENING WAZ026-027-520.
&&
THREAT INDEX
TODAY : YELLOW
THURSDAY : YELLOW
FRIDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
98/91/84/84
AREA FORECAST DISCUSSION
NWS MEDFORD OR
930 AM PDT WED JUL 31 2013
.SHORT TERM...A SHORTWAVE HAS MOVED OVER THE AREA THIS MORNING.
HOWEVER DESPITE ELEVATED INSTABILITY AND A JET ALOFT WE HAVE NOT
SEEN THUNDERSTORMS DEVELOP THIS MORNING WEST OF THE CASCADES. THE
LATEST RAP FORECAST SHOWS SOME PRECIPITATION AND POSSIBLE
THUNDERSTORM DEVELOPMENT IN PORTIONS OF DOUGLAS COUNTY AS THIS
SHORTWAVE CONTINUES TO MOVE NORTH THIS MORNING. SO WILL LEAVE
THUNDERSTORMS IN THE WESTERN VALLEYS FOR NOW BUT MAY UPDATE LATE
THIS MORNING IF NOTHING DEVELOPS TO REMOVE THEM FROM JOSEPHINE
COUNTY AND WESTERN DOUGLAS COUNTY. FURTHER EAST THIS MORNING SOME
WEAK SHOWERS HAVE DEVELOPED OVER MODOC AND LAKE COUNTY. HAVE ADDED
THESE TO THE FORECAST. THESE ARE VERY HIGH BASED AND EXPECT LITTLE
IF ANY PRECIPITATION TO REACH THE GROUND. THE SHORTWAVE ASSOCIATED
WITH THESE SHOWERS IS EXPECTED TO TRACK NORTH-NORTHEAST TODAY AND
OUT OF THE AREA IN THE AFTERNOON. WILL MONITOR THIS ISSUE AS WELL.
THEN IN THE AFTERNOON AND EVENING TODAY, THE FORECAST IS ON TRACK
FOR ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP FROM THE
SOUTHERN OREGON CASCADES EAST INTO KLAMATH AND NORTHERN LAKE
COUNTY. ALSO SOME ISOLATED THUNDERSTORMS MAY DEVELOP OVER THE
SISKIYOUS AND MOVE INTO THE ROGUE VALLEY. ADDITIONALLY THE WESTERN
FOOTHILLS OF THE CASCADES IN JACKSON AND DOUGLAS COUNTIES MAY SEE
THUNDERSTORMS AS WELL. HAVE ADDED ISOLATED THUNDERSTORMS INTO THE
AFTERNOON AND EVENING FORECAST TODAY FOR AREAS FURTHER SOUTH WHERE
THE RAP, WRF, NAM AND GFS ARE SHOWING A POTENTIAL FOR CONVECTION -
THIS INCLUDES CENTRAL AND EASTERN SISKIYOU COUNTY AND FAR
NORTHWEST MODOC COUNTY.
SMOKE REMAINS A CONCERN OVER SOUTHWEST PORTIONS OF THE AREA AND
ESPECIALLY IN THE WESTERN SOUTHERN OREGON VALLEYS. THE LATEST
SMOKE FORECAST FOR SURFACE SMOKE INDICATES THAT CONDITIONS MAY
IMPROVE ON THURSDAY AROUND LATE MORNING BUT DEGRADE AGAIN IN THE
LATE AFTERNOON AND EVENING.
&&
.AVIATION...WILDFIRES BURNING IN DOUGLAS AND JOSEPHINE COUNTIES
WILL CONTINUE TO PRODUCE PLENTY OF SMOKE ACROSS SOUTHWEST OREGON
AND NORTHERN CALIFORNIA. THIS SMOKE WILL CAUSE MOUNTAIN
OBSCURATIONS AND REDUCE VISIBILITIES AT LOWER ELEVATIONS...EVEN
DOWN TO IFR AT TIMES.
THERE IS A SLIGHT CHANCE OF DRY THUNDERSTORMS THIS MORNING
ACROSS THE INLAND WEST SIDE VALLEYS OF OREGON AND AREAS NEAR THE
CASCADES AS WINDS AND MOISTURE INCREASE ALOFT. BY THIS AFTERNOON
AND EVENING...THUNDERSTORMS WILL ALSO BE POSSIBLE IN AND EAST OF
THE CASCADES IN OREGON, ESPECIALLY AROUND CRATER LAKE AND THE EAST
SIDE NORTH OF KLMT.
ELSEWHERE...AWAY FROM THE FIRES...EXPECT VFR, BUT MARINE STRATUS
WILL BRING MVFR/IFR CIGS AND PATCHY FOG TO COASTAL AREAS, MAINLY
NORTH OF CAPE BLANCO AND ALSO NEAR BROOKINGS. SOME OF THESE CIGS
WILL SPREAD INLAND TO THE UMPQUA BASIN. STRATUS WILL ERODE BACK TO
THE COASTLINE BY LATE MORNING.
&&
.PREV DISCUSSION... /ISSUED 100 AM PDT WED JUL 31 2013/
DISCUSSION...31/00Z NAM/GFS IN.
THE MAIN STORY THIS MORNING IS THE EXTREMELY SMOKY CONDITIONS OVER
PORTIONS OF SOUTHWEST OREGON AND NORTHERN CALIFORNIA. THERE IS
ALSO THE THREAT OF THUNDERSTORM ACTIVITY NOW THROUGH THURSDAY.
OTHER THAN THAT THERE IS MARINE STRATUS ALONG PORTIONS OF THE
COAST AND LOTS OF MIDDLE AND HIGH LEVEL CLOUD COVERAGE ASSOCIATED
WITH AN INCOMING SHORT WAVE.
A LONG WAVE UPPER TROUGH IS NOW OFFSHORE NEAR 130W. SHORT WAVES
EJECTING FROM THIS TROUGH WILL ENHANCE UPPER LEVEL INSTABILITY AND
THUS INCREASE THE CHANCES OF CONVECTION. THE FIRST IN THE SERIES
IS NOW MOVING THROUGH THE AREA. A SECOND WEAKER WAVE WILL MOVE
THROUGH WEDNESDAY AFTERNOON AND EVENING. SEVERAL MORE WEAKER WAVES
WILL FOLLOW WEDNESDAY NIGHT INTO THURSDAY AS THE LONG WAVE TROUGH
APPROACHES THE COAST. THE TROUGH WILL MOVE ONSHORE THURSDAY NIGHT
BUT WILL REMAIN OVER THE PACIFIC NORTHWEST AS SHORT WAVES MOVE
DOWN THE BACKSIDE OF THE TROUGH AND SLOW ITS PROGRESS.
THE EVENING SHIFT DID AN EXCELLENT ANALYSIS OF THE CONVECTION
POTENTIAL THROUGH WEDNESDAY. IT FOLLOWS WITH SOME ADDITIONAL
INFORMATION ADDED FROM THE 31/00Z RUNS.
31/00Z GUIDANCE SHOWS INCREASING MID LEVEL INSTABILITY AS A SHORT
WAVE ARRIVES AND MOVES THROUGH WHICH MEANS THE POTENTIAL FOR
NOCTURNAL THUNDERSTORMS TUESDAY NIGHT. THE 31/00Z KMFR SOUNDING
SHOWS INCREASING MOISTURE ALOFT BUT IS ALSO OF THE INVERTED-V TYPE
BELOW 700 MB...WHICH MEANS VERY DRY AIR REMAINS IN THE LOW
LEVELS. THUS...ANY THUNDERSTORMS THAT DO DEVELOP ARE LIKELY TO BE
DRY AND MAY RESULT IN MORE FIRE STARTS. THESE STORMS WOULD ALSO BE
CAPABLE OF STRONG GUSTY DOWNDRAFT WINDS (DCAPES > 500 J/KG) WHICH
WOULD BE VERY HAZARDOUS TO PERSONNEL FIGHTING EXISTING FIRES.
CONDITIONS WILL CONTINUE TO DESTABILIZE LATER THIS MORNING INTO
THIS AFTERNOON. THE LATEST DLP (DRY LIGHTNING POTENTIAL) GUIDANCE
SHOWS THE GREATEST THREAT FOR DRY STORMS ON THE WEST SIDE FROM
12Z-18Z WEDNESDAY WITH CONDITIONS BECOMING VERY UNSTABLE IN THE
AFTERNOON (LI`S -4 TO -6, MID LEVEL LAPSE RATES 8.5C/KM, AND CAPES
> 500 J/KG). THE MAIN THREAT WILL BE OVER THE WESTERN INTERIOR
VALLEYS AND THE CASCADES. THE STORMS WILL TEND TO BECOME WETTER
WEDNESDAY AFTERNOON OVER THE WEST SIDE...BUT THEY`LL BE MOVING
RIGHT ALONG...SO PRECIPITATION TOTALS WILL REMAIN LOW.
THE MAIN THREAT AREA WILL SHIFT TO THE CASCADES AND EAST SIDE
THURSDAY AS A MARINE PUSH BRINGS IN COOLER AIR AND MORE STABLE
CONDITIONS TO THE WEST SIDE. MODEL LIFTED INDICES ARE NOT AS
IMPRESSIVE THEN AS THEY ARE FOR WEDNESDAY. EXPECT CONTINUED
THUNDERSTORM ACTIVITY FROM THE CASCADES EAST BUT COVERAGE AND
INTENSITY WILL BE LESS. FRIDAY WILL BE MORE STABLE. THE MAIN
THREAT AREA BY THAT TIME WILL BE EAST OF THE CASCADES. IF THE
31/00Z GFS VERIFIES THERE WILL BE NO THUNDERSTORMS FRIDAY OR
SATURDAY. THE NAM IS SLIGHTLY MORE UNSTABLE AND MAY SUPPORT
ISOLATED COVERAGE OVER LAKE COUNTY FRIDAY.
WEAK LOW PRESSURE WILL LINGER OVER THE AREA THROUGH THE WEEKEND
WITH A WARMING TREND. UNSTABLE CONDITIONS MAY REDEVELOP SUNDAY AND
THE CURRENT FORECAST INCLUDES A SLIGHT CHANCE OF AFTERNOON/EVENING
THUNDERSTORMS OVER THE HIGHER TERRAIN. THE TROUGH IS CURRENTLY
PROGGED TO SHEAR EARLY NEXT WEEK...LEAVING A CUTOFF LOW OFF THE
CALIFORNIA COAST. AT THAT POINT THE FORECAST WILL BE DEPENDENT ON
THE LOCATION OF THE CUTOFF...WHICH IS A REAL DICEY FORECAST THIS
FAR OUT. THE LOW WILL LIKELY REMAIN WHEREVER IT SETS UP UNTIL AT
LEAST THE MIDDLE OF NEXT WEEK.
AVIATION...WILDFIRES BURNING IN DOUGLAS AND JOSEPHINE COUNTIES
WILL CONTINUE TO PRODUCE PLENTY OF SMOKE ACROSS SOUTHWEST OREGON
AND NORTHERN CALIFORNIA. THIS SMOKE WILL CAUSE MOUNTAIN
OBSCURATIONS AND REDUCE VISIBILITIES AT LOWER ELEVATIONS...EVEN
DOWN TO IFR AT TIMES.
ISOLATED DRY THUNDERSTORMS MAY DEVELOP LATER THIS MORNING ACROSS
THE INLAND WEST SIDE VALLEYS OF OREGON AND AREAS NEAR THE CASCADES
AS WINDS AND MOISTURE INCREASE ALOFT. BY THIS AFTERNOON AND
EVENING...THUNDERSTORMS WILL ALSO BE POSSIBLE IN AND EAST OF THE
CASCADES IN OREGON...ESPECIALLY AROUND CRATER LAKE AND THE EAST
SIDE NORTH OF KLMT.
ELSEWHERE...AWAY FROM THE FIRES...EXPECT VFR...BUT MARINE STRATUS
WILL BRING MVFR/IFR CIGS AND PATCHY FOG TO COASTAL AREAS...MAINLY
NORTH OF CAPE BLANCO AND ALSO NEAR BROOKINGS. SOME OF THESE CIGS
WILL SPREAD INLAND TO THE UMPQUA BASIN. STRATUS WILL ERODE BACK TO
THE COASTLINE BY LATE MORNING. -WRIGHT
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR ORZ021-024.
RED FLAG WARNING UNTIL 8 PM PDT THURSDAY FOR ORZ023-026.
RED FLAG WARNING UNTIL 2 PM PDT THIS AFTERNOON FOR ORZ022.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY FOR
ORZ025-027-030-031.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY FOR ORZ028-029.
CA...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR CAZ080.
PACIFIC COASTAL WATERS...NONE.
$$
CC
AREA FORECAST DISCUSSION
NWS PENDLETON OR
921 AM PDT WED JUL 31 2013
.SHORT TERM...UPDATE...AN UPPER LEVEL LOW, WITH EMBEDDED SHORTWAVE
DISTURBANCES, IS OFF THE PACIFIC COASTLINE THIS MORNING ADVECTING
MOISTURE INTO OUR REGION THIS MORNING. RADAR INDICATES THAT SHOWERS
HAVE DEVELOPED OVER THE FOOTHILLS OF THE BLUE MOUNTAINS AND THE JOHN
DAY HIGHLANDS, WHILE THE CASCADES HAVE NO RETURNS SHOWING UP. HAVE
UPDATED THE POP GRIDS THIS MORNING TO INDICATE AN ISOLATED CHANCE OF
SHOWERS FOR MAINLY THE JOHN DAY HIGHLANDS AND THE BLUE MOUNTAINS.
ALSO, AS A RESULT OF CLOUDINESS FROM MORNING ACTIVITY, HAVE TRIMMED
BACK THE MAX TEMPERATURES FOR MOST LOCATIONS.
WATER VAPOR IS SHOWING A SHORTWAVE IMPULSE NEAR THE CALIFORNIA AND
OREGON BORDER, MOVING NORTHEAST TOWARDS OUR CWA. IT IS ANTICIPATED
THAT THIS IMPULSE WILL ARRIVE IN OUR AREA BY THIS AFTERNOON,
PROVIDING A FOCUSING MECHANISM AND LIFT FOR INCREASED THUNDERSTORM
ACTIVITY LATER TODAY. MARGINAL INSTABILITY OF APPROXIMATELY 500 J
PER KG OF ELEVATED CAPE, A STRONG INVERTED V PROFILE IN FORECASTED
SOUNDINGS, AND NEAR 50 KTS ARE CONDUCIVE FACTORS FOR STRONG
THUNDERSTORMS CAPABLE OF PRODUCING STRONG WINDS AND EVEN SOME SMALL
HAIL. LATEST HRRR RUNS AND HI-RES WRF ENSEMBLE INDICATE THAT THE
STORMS WILL START MAINLY OVER THE CENTRAL AND EASTERN OREGON
HIGHLANDS, THEN PROPAGATE INTO THE LOWER COLUMBIA BASIN LATER THIS
EVENING. BIEDA/SOLOMON
.LONG TERM...PREVIOUS DISCUSSION...FRIDAY NIGHT THROUGH
WEDNESDAY...AN UPPER LOW PRESSURE SYSTEM CENTERED OVER EAST CENTRAL
WASHINGTON FRIDAY NIGHT WILL MOVE OFF TO THE NORTHEAST ON SATURDAY.
IN ITS WAKE THERE WILL BE A REMNANT UPPER TROUGH OVER THE PACIFIC
NORTHWEST AND THE FORECAST AREA. THIS WILL KEEP UNSETTLED AND COOL
CONDITIONS OVER THE FORECAST AREA...ESPECIALLY IN THE NORTHERN
PORTIONS OF THE CWA ON SATURDAY. THIS UNSETTLED WEATHER WILL
DECREASE SUNDAY AND MONDAY AS AN UPPER RIDGE BUILDS OVER THE REGION.
THE UPPER RIDGE WILL BE DEVELOPING IN RESPONSE TO A NEW UPPER LOW
THAT WILL DEVELOP OFF THE NORTHERN CALIFORNIA COAST. THE RESULT WILL
BE MORE DRY CONDITIONS AND A WARMING TREND FOR EARLY NEXT WEEK. THE
LONG RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS SCENARIO
THROUGH MONDAY AND TUESDAY THOUGH THERE WILL BE SOME DIFFERENCES TO
EXACTLY WHERE THE UPPER LOW WILL BE CENTERED OFF THE COAST. ON
WEDNESDAY THE MODEL DIFFERENCES BECOME GREATER BUT STILL SHOW A
RIDGE OVER THE CWA WITH AN UPPER LOW OFF THE CALIFORNIA COAST. 88
&&
.AVIATION...PREVIOUS DISCUSSION...12Z TAFS...VFR CONDITIONS WILL
PREVAIL. HOWEVER THERE WILL BE AN ABUNDANCE OF HIGH CLOUDS AND SOME
MID LEVEL CLOUDS AS WELL BETWEEN 100-120 AND FROM 200-250. THERE
WILL BE ISOLATED TO SCATTERED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS THAT WILL AFFECT KDLS...KRDM...KBDN AND KYKM TODAY.
THE THUNDERSTORM ACTIVITY WILL THEN SPREAD OVER THE REST OF THE AREA
BY THIS EVENING. MOST STORMS THAT DEVELOP WILL BE WEAK BUT THERE
COULD BE SOME TEMPORARY MVFR CONDITIONS DUE TO LOWERING VISIBILITY
IN THE IMMEDIATE VICINITY OF SHOWERS WITH THE STRONGER STORMS.
THUNDERSTORMS WILL BE HIGH BASED SO CIGS WILL STAY WELL ABOVE VFR
MINIMUMS AT ALL TAF SITES. WINDS WILL BE LIGHT AND GENERALLY 5 TO 15
KTS THROUGH TONIGHT. AREAS OF SMOKE WILL CONTINUE IN THE VICINITY OF
WILDFIRES. 88
&&
.FIRE WEATHER...A LOW PRESSURE SYSTEM WILL BRING THUNDERSTORMS TO
THE FORECAST AREA TODAY. THE FIRST DISTURBANCE IS ROTATING AROUND
THE LOW AND WILL ENTER OUR AREA THIS AFTERNOON. A RED FLAG WARNING
ARE FOR ALL FIRE WEATHER ZONES THROUGH THURSDAY EVENING. WHILE
THUNDERSTORMS WILL START OUT WITH LIGHT PRECIPITATION...EXPECT THEM
TO BECOME WETTER TODAY ALONG THE CASCADES AND THEN TONIGHT INTO
TOMORROW FOR THE REST OF THE REGION. THUNDERSTORMS WILL CONTINUE
TOMORROW AS THE LOW MOVES OVERHEAD. ALL RED FLAG WARNINGS WILL END
TOMORROW NIGHT AND EXPECT THUNDERSTORMS TO DECREASE IN COVERAGE
OVERNIGHT ON TOMORROW NIGHT AND INTO FRIDAY. THUNDERSTORMS ARE
EXPECTED TO HAVE THE POTENTIAL OF PRODUCING STRONG GUSTY WINDS.
SURFACE WINDS WILL ALSO INCREASE ON TOMORROW AS THE LOW MOVES
EASTWARD WITH LOCALLY BREEZY TO WINDY CONDITIONS ESPECIALLY IN THE
COLUMBIA BASIN AND NEAR THE CASCADE GAPS.
&&
.PREV DISCUSSION... /ISSUED 700 AM PDT WED JUL 31 2013/
SHORT TERM...TODAY THROUGH FRIDAY AFTERNOON...TROUGH OFFSHORE SETS
UP CONDITIONS FAVORABLE FOR THUNDERSTORMS FOR THE NEXT THREE DAYS.
STRONG VERTICAL WIND SHEAR TODAY MAY SUPPORT A FEW STRONG OR
MARGINALLY SEVERE STORMS BUT INSTABILITY IS ONLY MARGINAL TODAY. AS
SUCH A FEW STORMS TODAY AND THIS EVENING MAY BE CAPABLE OF PRODUCING
MARGINALLY SEVERE HAIL TO ONE INCH IN DIAMETER AND GUSTY WINDS.
THUNDERSTORMS WILL BEGIN OVER THE MOUNTAINS IN CENTRAL OREGON AND
THE SOUTHERN BLUE MOUNTAINS BY MID AFTERNOON TODAY. SOME STORMS MAY
MOVE NORTH INTO THE LOWER COLUMBIA BASIN AS WELL AS NORTH CENTRAL
OREGON IN THE EVENING.
A MID/UPPER LEVEL SHORT WAVE SWINGS EAST OF THE OREGON CASCADES
OVERNIGHT THUS SOME STRONG DYNAMIC LIFT, WHICH WILL TRIGGER ISOLATED
TO SCATTERED NOCTURNAL THUNDERSTORMS IN THE BLUE MOUNTAINS TOWARD
DAYBREAK THURSDAY MORNING WITH STORMS BEING TRIGGERED BY DYNAMIC
LIFT FOR THE DURATION OF THURSDAY. STORMS ON THURSDAY ARE NOT
EXPECTED TO BE SEVERE. ALTHOUGH THE ATMOSPHERE WILL BE MUCH MORE
UNSTABLE DURING THE DAYTIME ON THURSDAY, ONLY WEAK VERTICAL WIND
SHEAR IS EXPECTED SO THE THUNDERSTORMS THURSDAY SHOULD BE WEAKER
THAN STORMS TODAY.
THE FOCUS FOR THUNDERSTORMS SHIFTS TO NE OREGON AND SE WASHINGTON ON
FRIDAY AS THE UPPER LEVEL TROUGH SWINGS EAST OF THE CASCADES. POLAN
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 86 60 86 58 / 20 30 40 30
ALW 90 63 88 62 / 20 30 30 40
PSC 91 63 90 63 / 10 30 30 40
YKM 86 63 89 62 / 20 30 30 40
HRI 89 61 89 62 / 20 30 30 30
ELN 87 60 87 62 / 20 30 40 50
RDM 83 52 79 45 / 30 30 60 20
LGD 89 55 82 53 / 20 30 50 50
GCD 89 56 82 53 / 30 30 60 30
DLS 88 61 82 60 / 30 30 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING FROM 8 PM THIS EVENING TO 11 PM PDT THURSDAY
ORZ044-050-508.
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THURSDAY
ORZ049-502-503-505>507.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY ORZ041-042-509.
WA...RED FLAG WARNING FROM 8 PM THIS EVENING TO 11 PM PDT THURSDAY
WAZ026>029.
RED FLAG WARNING FROM 2 PM THIS AFTERNOON TO 11 PM PDT THURSDAY
WAZ030.
RED FLAG WARNING UNTIL 11 PM PDT THURSDAY WAZ024-520-521.
FIRE WEATHER WATCH FROM 8 PM PDT THIS EVENING THROUGH THURSDAY
EVENING WAZ026-027-520.
&&
THREAT INDEX
TODAY : YELLOW
THURSDAY : YELLOW
FRIDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
98/91/84/84
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
346 PM CDT WED JUL 31 2013
.SHORT TERM...
A WEAK COLD FRONT WAS SITUATED ROUGHLY ALONG THE I-20 CORRIDOR THIS
AFTERNOON. THIS FRONT IS EXPECTED TO DROP A BIT FARTHER SOUTH INTO
NORTHERN PORTIONS OF THE CONCHO VALLEY AND HEARTLAND BEFORE STALLING
OUT TONIGHT. THE FRONT WILL BECOME MORE DIFFUSE ON THURSDAY AND
SHOULD WASH OUT ACROSS THE AREA BY AFTERNOON. AS OF 3 PM...ISOLATED
CONVECTION HAS FORMED JUST AHEAD OF THE FRONT OVER SOUTHERN PORTIONS
OF THE BIG COUNTRY. WILL KEEP ISOLATED CONVECTION IN THE FORECAST
THROUGH EARLY EVENING WITH ACTIVITY EXPECTED TO DISSIPATE AFTER
SUNSET WITH LOSS OF HEATING.
CONVECTION HAS ALSO DEVELOPED ACROSS THE HIGHER TERRAIN IN EASTERN
NEW MEXICO THIS AFTERNOON. LATEST NAM AND HRRR INDICATE THAT THIS
ACTIVITY MAY MAKE A RUN AT OUR WESTERN COUNTIES TOWARDS DAYBREAK
THURSDAY AS IT WEAKENS. NOT CONFIDENT THAT THIS WILL HAPPEN SO KEPT
THE FORECAST DRY OVERNIGHT. DRY AND HOT CONDITIONS CONTINUE THURSDAY
AFTERNOON WITH HIGHS 99 TO 102 AND HEAT INDICES 102 TO 105 DEGREES.
24
.LONG TERM...
HOT AND DRY CONDITIONS WILL DOMINATE THE WEATHER ACROSS WEST CENTRAL
TEXAS FROM FRIDAY THROUGH AT LEAST THE MIDDLE OF NEXT WEEK. THE
SURFACE HIGH THAT IS CURRENTLY CENTERED OVER NEW MEXICO WILL
REPOSITION ITSELF OVER TEXAS THROUGH AT LEAST THE NEXT 7 DAYS. THIS
WILL RESULT IN NEAR NIL RAIN CHANCES...WITH HIGH TEMPERATURES
RANGING FROM 98 TO 103...WHILE OVERNIGHT LOWS FALL INTO THE MID AND
UPPER 70S. VERY LITTLE RELIEF IN THE HOT AND DRY PATTERN IS EXPECTED
THROUGH THE NEXT 7 DAYS...AND POSSIBLY BEYOND...AS THE UPPER LEVEL
HIGH REMAINS PARKED OVER THE LONE STAR STATE.
DANIELS
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 76 100 75 101 75 / 10 5 0 0 0
SAN ANGELO 75 101 75 101 74 / 20 5 0 0 0
JUNCTION 75 99 73 99 72 / 10 0 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
24/DANIELS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
202 PM EDT WED JUL 31 2013
.SYNOPSIS...
AN UPPER-LEVEL DISTURBANCE WILL TRACK FROM THE TENNESSEE VALLEY
TOWARD THE SOUTHEAST STATES THROUGH THURSDAY BRINGING RAIN TO THE
REGION TODAY ALONG WITH UNSEASONABLY COOL TEMPERATURES. A COLD
FRONT WILL MOVE THROUGH THE AREA THURSDAY...RESULTING IN
DECREASING CLOUDS AND MORE SCATTERED SHOWER ACTIVITY. WEAK HIGH
PRESSURE WILL THEN DOMINATE THROUGH SATURDAY WHEN THE NEXT COLD
FRONT ARRIVES FROM THE OHIO VALLEY. WARMER TEMPERATURES ARE
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND WITH SCATTERED
MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1255 PM EDT WEDNESDAY...
EARLY AFTERNOON RADAR TRENDS DEPICT THE AREA OF PRECIPITATION THAT
HAS BEEN MAKING ITS WAY SLOWLY EASTWARD ACROSS THE REGION IS
CENTERED ALONG A LINE FROM NEAR MARTINSBURG VA TO LEWISBURG WV.
AREAS ALONG AND EAST OF A LYNCHBURG VA TO DANVILLE VA LINE HAVE
EXPERIENCED LITTLE IF ANY RAIN SO FAR TODAY...BUT IN THIS
AREA...COVERAGE OF RAIN WILL BE INCREASING THIS AFTERNOON.
ALSO..THIS REGION...AND WESTWARD ALONG THE VA/NC BORDER WILL SEE
INCREASING INSTABILITY...AND THE POTENTIAL FOR HEAVIER RAIN
SHOWERS AND A STRAY THUNDERSTORM OR TWO. AREAS ALONG AND WEST OF
I-77 IN VA AND NC ARE EXPERIENCING THE LEAST AMOUNT OF
PRECIPITATION CURRENTLY. THIS AREA WILL SEE AN INCREASE IN
COVERAGE BY THE LATE AFTERNOON THANKS TO AN IMPULSE IN KY HEADING
EASTWARD...AND INCREASED INSTABILITY OVER THE NORTHERN MOUNTAINS
AND FOOTHILLS OF NC. HAVE TWEAKED THE HOURLY TEMPERATURE...DEW
POINT...WIND...AND SKY COVER THROUGH THE LATE AFTERNOON BASED UPON
THE CURRENT OBSERVATIONS AND EXPECTED TRENDS. HAVE INCREASED HIGH
TEMPERATURES BY A FEW DEGREES IN THE EAST...AND DECREASE BY A FEW
IN THE MOUNTAINS.
AS OF 1037 AM EDT WEDNESDAY...
HAVE MADE A FEW TWEAKS TO POPS FOR THE REST OF THIS MORNING BASED
ON CURRENT RADAR TRENDS...OTHERWISE CURRENT FORECAST ON-TRACK.
WHILE THE MORNING ANALYSIS SHOWS THAT THERE IS STILL PLENTY OF
SHORT WAVE ENERGY UPSTREAM...PARTICULARLY OVER THE SOUTHERN
APPALACHIANS...NOTED THAT THE LATEST HRRR RUN SHOWS THE BEST
COVERAGE OF NEW PRECIP DEVELOPMENT OCCURRING ACROSS THE SOUTH-
CENTRAL AND EASTERN ZONES LATER THIS AFTERNOON.
PREV DISC AS OF 430 AM EDT WEDNESDAY...
FOCUS FOR THE NEAR TERM WILL BE ONUPPER DISTURBANCE TRACKING FROM
THE TENNESSEE VALLEY SE TOWARD GA/SC THROUGH EARLY THU. AS
EXPECTED FOR THE PAST SEVERAL DAYS...THIS WILL BE MAINLY A -RA
EVENT FOR OUR CWA...WITH VERY LIMITED HEATING AND AN IN SITU WEDGE
DEVELOPING FROM EXTENSIVE CLOUD COVER AND -RA FALLING INTO THE
RELATIVELY DRY AIR FOR THE END OF JULY...ONLY EXPECTING -RA WITH
ISOLD MODERATE RA THROUGH 12Z THU. WHILE THERE ARE SOME
DIFFERENCES BETWEEN THE GFS/ECMWF/CMC WITH A COOLER/LESS QPF
SOLUTION AS COMPARED TO THE MUCH WETTER/STORMIER NAM...HAVE LEANED
HEAVILY TOWARD THE GFS/ECMWF/CMC SUITE WITH NEAR ZERO INSTABILITY
INDICATED TODAY PER EARLIER THINKING. CONSEQUENTLY...HAVE REMOVED
ALL MENTION OF TSRA WITH THIS PACKAGE THROUGH 12Z THU. OVERALL
RAINFALL FOR MOST OF THE CWA SHOULD BE IN THE 0.5 TO 1.0 INCH
RANGE AT BEST WITH -RA DOMINATING MOST OF THE TIME. NOTE...LATEST
1-2 DAY WPC QPF MOSTLY ONE INCH OR LESS. THUS...NO CONCERNS FOR OR
NEED FOR A FLASH FLOOD WATCH WITHIN THIS PERIOD.
HAVE CONTINUED THE TREND OF ADVERTISING BELOW TO MUCH BELOW NORMAL
TEMPERATURES TODAY PER REASONING NOTED ABOVE OF IN SITU WEDGE
FROM CLOUDS AND RAIN BEGINNING EARLY...WITH DEWPOINTS STILL IN THE
MID 50S TO LOWER 60S...RATHER LOW FOR LATE JULY. DIURNAL RANGE
WILL BE LIMITED AND COOLING OVERNIGHT INTO THU MORNING WILL ALSO
BE LIMITED...WITH MOST AREAS AT LEAST 5 DEG WARMER THAN THIS
MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 232 PM EDT TUESDAY...
ANOTHER WEAK UPPER WAVE REINFORCING TROUGH WITH ASSOCIATE SURFACE
FRONT TO PUSH THROUGH ON THURSDAY. SOME SIGNS THIS WILL CONTINUE
TO TAP SOME GULF MOISTURE BUT NOTHING LIKE WHAT WE SAW THIS PAST
WEEKEND AND LOOKS TO BE A PROGRESSIVE SYSTEM SO PREFER FASTER
SOLUTIONS...WHICH ARE ECMWF AND NAM VS. SLOWER GFS. PRECIP COULD
MOVE EAST OF FCST AREA BY 21Z BUT HAVE LEFT SOME LOW CHC POPS IN
THROUGH 03Z DUE TO SOME UNCERTAINTY...BUT FEELING IS THIS IS
LIKELY TO MOVE THROUGH FASTER VS. SLOWER. WE SHOULD LOSE ANY WEAK
WEDGE AHEAD OF THE FRONT BY MORNING...SO MODEST INSTABILITY
ESPECIALLY OUT EAST AHEAD OF FRONT FROM MIDDAY ONWARD...SO THUNDER
IN GRIDS AFTER 15Z AND HIGHEST QPF AHEAD OF FRONT IN FAR EAST BY
AFTERNOON. NOT READY TO GO CATEGORICAL...MAINLY DUE TO THE
LINGERING UNCERTAINTY IN TIMING AND WHERE ALONG FRONT THERE MIGHT
BE MORE CONTINUOUS COVERAGE VS. SCATTERED SHOWERS/STORMS. AT THIS
POINT SEVERE CHANCES LOOK MINIMAL GIVEN MODERATE INSTABILITY AND
FAIRLY WEAK SHEAR. ALSO DOES NOT APPEAR CONVECTION ORGANIZED
ENOUGH FOR MUCH OF A FLASH FLOOD THREAT...NOR IS THERE ANY UPSLOPE
COMPONENT ALONG BLUE RIDGE AND AREAS OF CONVECTION SHOULD BE
MOVING QUICKLY WITH FRONTAL BOUNDARY. TEMPERATURES IN MOST PLACES
SHOULD BE ON COOL SIDE OF GUIDANCE...BUT WILL HAVE TO CONSIDER
POTENTIAL FOR DECENT AMOUNT OF SUN IN THE WEST IF FRONT MOVES
FASTER...EXCEPT FOR FAR WESTERN SLOPES WHERE CLOUDS AND A FEW
SHOWERS COULD LINGER. SO SOME SPOTS IN WESTERN VALLEYS MAY WARM TO
AS MUCH OR HIGHER THAN PIEDMONT...DEPENDING ON TIMING OF
FRONT...LINGERING PRECIP EAST IN AFTERNOON...AND SUNSHINE IN WEST.
SOMEWHAT DRIER AIR BUT NOT NECESSARILY MUCH COOLER AIRMASS BEHIND
FRONT FOR THURS NIGHT INTO FRIDAY. DOWNSLOPE AND MORE SUN SHOULD
CONTRIBUTE TO WARMER TEMPS...ESPECIALLY OUT EAST BUT PROBABLY
EVERYWHERE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 420 AM EDT WEDNESDAY...
ANOTHER FRONT TO SLIDE DOWN FROM NORTH BY END OF WEEKEND WITH WAVE
POSSIBLY BRINGING SHOWERS IN AHEAD OF IT AS EARLY AS SATURDAY
MORNING. TRICKY TO KNOW THIS FAR OUT JUST HOW MUCH THIS FRONT WILL
SAG SOUTH ACROSS FCST AREA...AND WHETHER BY LATE SUNDAY IT WILL
ACTUALLY DROP SOUTH OF THE AREA OR STALL ACROSS US...BUT LATEST
TRENDS SUGGEST IT MAY TRY TO MAKE IT THROUGH THUS MADE SOME
ADJUSTMENTS TO POPS BASED ON THIS. TEMPS LIKELY AT OR JUST BELOW
NORMAL THROUGH WEEKEND AND INTO EARLY NEXT WEEK WITH THE EFFECTS OF
THIS FRONTAL BOUNDARY PASSING THROUGH...AND THEN THE POSSIBILITY OF
LIFTING BACK ACROSS US AS A WARM FRONT BRINGING PRECIP CHANCES
AROUND WITH ONLY A SHORT BREAK...IF ANY...LATE SUNDAY INTO MONDAY.
MUCH UNCERTAINTY AT THIS TIME HOWEVER.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 145 PM EDT WEDNESDAY...
EXPANSIVE AREA OF LIGHT RAIN CONTINUES TO PROGRESS EAST ACROSS THE
REGION WITH THE GREATEST CONCENTRATION ALONG A LINE FROM KLWB-
KLYH. MOST AREAS WITHIN THIS REGION OF RAIN ARE EXPERIENCING VFR
CONDITIONS WITH POCKETS OF MVFR CIGS/VSBYS. WEST OF THE MAIN RAIN
AREA...THERE IS A GREATER EXPANSE OF MVFR CONDITIONS WITH EITHER
DRIZZLE OR VERY PATCHY LIGHT RAIN. AS THE DAY PROGRESSESS...MODEL
GUIDANCE SUGGESTS AREAS ALONG AND EAST OF A KLYH-KDAN LINE...AND
ALONG AND SOUTH OF A KDAH-KGEV LINE MAY BECOME UNSTABLE ENOUGH FOR
DISTINCT HEAVIER RAIN SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO.
AS WE PROGRESS INTO THE OVERNIGHT HOURS...LOW PRESSURE WILL
PROGRESS FROM KENTUCKY TO PENNSYLVANIA WHICH WILL BRING A WARM
FRONT NORTH THROUGH THE REGION ON THE EAST SIDE OF THE LOW. WE ARE
EXPECTING A GENERAL TREND TOWARD LOWERING FLIGHT CONDITIONS
DURING THIS PERIOD TO IFR AT MOST LOCATIONS ALONG WITH PATCHY
LIGHT RAIN...DRIZZLE AND MIST/FOG. WINDS DURING THE PERIOD WILL
REMAIN LIGHT AND VARIABLE BUT TREND LIGHT FROM THE SOUTHWEST
TOWARD DAYBREAK THURSDAY.
THE COLD FRONT ASSOCIATED WITH THE LOW IS EXPECTED TO MOVE INTO
THE WESTERN PART OF THE AREA AFTER 12Z/8AM THURSDAY. ANTICIPATE
WINDS TO BECOME WESTERLY LATE IN THE MORNING NEAR A KLWB-KBLF
LINE. FLIGHT CATEGORIES WILL GRADUALLY IMPROVE THROUGH THE MORNING
HEAD OF THE COLD FRONT...BUT ONCE THE FRONT MOVES THROUGH WESTERN
TERMINAL LOCATIONS...ANTICIPATE A QUICKER RATE. SHOWERS WILL BE
POSSIBLE ALONG THE FRONT BY LATE MORNING...WITH SOME ISOLATED
THUNDERSTORMS BY THE EARLY AFTERNOON.
THE INFLUENCE OF THE FRONT WILL CONTINUE TO PROVIDE SHOWERS ACROSS
PARTS OF THE REGION INTO THURSDAY EVENING...ESPECIALLY IN THE
EAST.
HIGH PRESSURE STARTS BUILDING INTO THE AREA BY LATE THURSDAY
NIGHT AND CONTIUE OVER THE AREA THROUGH EARLY SATURDAY. MAINLY VFR
CONDITIONS ARE EXPECTED DURING THIS PERIOD EXCEPT LATE AT NIGHT
AND EARLY MORNING HOURS WHEN MOUNTAIN AND RIVER VALLEY FOG WILL BE
POSSIBLE.
THE NEXT COLD FRONT IS PROGGED TO MOVE THROUGH THE AREA SATURDAY
EVENING INTO SUNDAY MORNING. ANTICPATE A RETURN OF SCATTERED
SHOWERS AND STORMS AND SOME AREAS OF SUB-VFR CONDITIONS.
HIGH PRESSURE AND MAINLY VFR CONDITIONS RETURN BY MONDAY. EARLY
MORNING FOG WILL AGAIN BE A POSSIBILITY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...DS/NP/RAB
SHORT TERM...SK
LONG TERM...RCS/SK
AVIATION...DS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1257 PM EDT WED JUL 31 2013
.SYNOPSIS...
AN UPPER-LEVEL DISTURBANCE WILL TRACK FROM THE TENNESSEE VALLEY
TOWARD THE SOUTHEAST STATES THROUGH THURSDAY BRINGING RAIN TO THE
REGION TODAY ALONG WITH UNSEASONABLY COOL TEMPERATURES. A COLD
FRONT WILL MOVE THROUGH THE AREA THURSDAY...RESULTING IN
DECREASING CLOUDS AND MORE SCATTERED SHOWER ACTIVITY. WEAK HIGH
PRESSURE WILL THEN DOMINATE THROUGH SATURDAY WHEN THE NEXT COLD
FRONT ARRIVES FROM THE OHIO VALLEY. WARMER TEMPERATURES ARE
EXPECTED FOR THE END OF THE WEEK INTO THE WEEKEND WITH SCATTERED
MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1255 PM EDT WEDNESDAY...
EARLY AFTERNOON RADAR TRENDS DEPICT THE AREA OF PRECIPITATION THAT
HAS BEEN MAKING ITS WAY SLOWLY EASTWARD ACROSS THE REGION IS
CENTERED ALONG A LINE FROM NEAR MARTINSBURG VA TO LEWISBURG WV.
AREAS ALONG AND EAST OF A LYNCHBURG VA TO DANVILLE VA LINE HAVE
EXPERIENCED LITTLE IF ANY RAIN SO FAR TODAY...BUT IN THIS
AREA...COVERAGE OF RAIN WILL BE INCREASING THIS AFTERNOON.
ALSO..THIS REGION...AND WESTWARD ALONG THE VA/NC BORDER WILL SEE
INCREASING INSTABILITY...AND THE POTENTIAL FOR HEAVIER RAIN
SHOWERS AND A STRAY THUNDERSTORM OR TWO. AREAS ALONG AND WEST OF
I-77 IN VA AND NC ARE EXPERIENCING THE LEAST AMOUNT OF
PRECIPITATION CURRENTLY. THIS AREA WILL SEE AN INCREASE IN
COVERAGE BY THE LATE AFTERNOON THANKS TO AN IMPULSE IN KY HEADING
EASTWARD...AND INCREASED INSTABILITY OVER THE NORTHERN MOUNTAINS
AND FOOTHILLS OF NC. HAVE TWEAKED THE HOURLY TEMPERATURE...DEW
POINT...WIND...AND SKY COVER THROUGH THE LATE AFTERNOON BASED UPON
THE CURRENT OBSERVATIONS AND EXPECTED TRENDS. HAVE INCREASED HIGH
TEMPERATURES BY A FEW DEGREES IN THE EAST...AND DECREASE BY A FEW
IN THE MOUNTAINS.
AS OF 1037 AM EDT WEDNESDAY...
HAVE MADE A FEW TWEAKS TO POPS FOR THE REST OF THIS MORNING BASED
ON CURRENT RADAR TRENDS...OTHERWISE CURRENT FORECAST ON-TRACK.
WHILE THE MORNING ANALYSIS SHOWS THAT THERE IS STILL PLENTY OF
SHORT WAVE ENERGY UPSTREAM...PARTICULARLY OVER THE SOUTHERN
APPALACHIANS...NOTED THAT THE LATEST HRRR RUN SHOWS THE BEST
COVERAGE OF NEW PRECIP DEVELOPMENT OCCURRING ACROSS THE SOUTH-
CENTRAL AND EASTERN ZONES LATER THIS AFTERNOON.
PREV DISC AS OF 430 AM EDT WEDNESDAY...
FOCUS FOR THE NEAR TERM WILL BE ONUPPER DISTURBANCE TRACKING FROM
THE TENNESSEE VALLEY SE TOWARD GA/SC THROUGH EARLY THU. AS
EXPECTED FOR THE PAST SEVERAL DAYS...THIS WILL BE MAINLY A -RA
EVENT FOR OUR CWA...WITH VERY LIMITED HEATING AND AN IN SITU WEDGE
DEVELOPING FROM EXTENSIVE CLOUD COVER AND -RA FALLING INTO THE
RELATIVELY DRY AIR FOR THE END OF JULY...ONLY EXPECTING -RA WITH
ISOLD MODERATE RA THROUGH 12Z THU. WHILE THERE ARE SOME
DIFFERENCES BETWEEN THE GFS/ECMWF/CMC WITH A COOLER/LESS QPF
SOLUTION AS COMPARED TO THE MUCH WETTER/STORMIER NAM...HAVE LEANED
HEAVILY TOWARD THE GFS/ECMWF/CMC SUITE WITH NEAR ZERO INSTABILITY
INDICATED TODAY PER EARLIER THINKING. CONSEQUENTLY...HAVE REMOVED
ALL MENTION OF TSRA WITH THIS PACKAGE THROUGH 12Z THU. OVERALL
RAINFALL FOR MOST OF THE CWA SHOULD BE IN THE 0.5 TO 1.0 INCH
RANGE AT BEST WITH -RA DOMINATING MOST OF THE TIME. NOTE...LATEST
1-2 DAY WPC QPF MOSTLY ONE INCH OR LESS. THUS...NO CONCERNS FOR OR
NEED FOR A FLASH FLOOD WATCH WITHIN THIS PERIOD.
HAVE CONTINUED THE TREND OF ADVERTISING BELOW TO MUCH BELOW NORMAL
TEMPERATURES TODAY PER REASONING NOTED ABOVE OF IN SITU WEDGE
FROM CLOUDS AND RAIN BEGINNING EARLY...WITH DEWPOINTS STILL IN THE
MID 50S TO LOWER 60S...RATHER LOW FOR LATE JULY. DIURNAL RANGE
WILL BE LIMITED AND COOLING OVERNIGHT INTO THU MORNING WILL ALSO
BE LIMITED...WITH MOST AREAS AT LEAST 5 DEG WARMER THAN THIS
MORNING.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 232 PM EDT TUESDAY...
ANOTHER WEAK UPPER WAVE REINFORCING TROUGH WITH ASSOCIATE SURFACE
FRONT TO PUSH THROUGH ON THURSDAY. SOME SIGNS THIS WILL CONTINUE
TO TAP SOME GULF MOISTURE BUT NOTHING LIKE WHAT WE SAW THIS PAST
WEEKEND AND LOOKS TO BE A PROGRESSIVE SYSTEM SO PREFER FASTER
SOLUTIONS...WHICH ARE ECMWF AND NAM VS. SLOWER GFS. PRECIP COULD
MOVE EAST OF FCST AREA BY 21Z BUT HAVE LEFT SOME LOW CHC POPS IN
THROUGH 03Z DUE TO SOME UNCERTAINTY...BUT FEELING IS THIS IS
LIKELY TO MOVE THROUGH FASTER VS. SLOWER. WE SHOULD LOSE ANY WEAK
WEDGE AHEAD OF THE FRONT BY MORNING...SO MODEST INSTABILITY
ESPECIALLY OUT EAST AHEAD OF FRONT FROM MIDDAY ONWARD...SO THUNDER
IN GRIDS AFTER 15Z AND HIGHEST QPF AHEAD OF FRONT IN FAR EAST BY
AFTERNOON. NOT READY TO GO CATEGORICAL...MAINLY DUE TO THE
LINGERING UNCERTAINTY IN TIMING AND WHERE ALONG FRONT THERE MIGHT
BE MORE CONTINUOUS COVERAGE VS. SCATTERED SHOWERS/STORMS. AT THIS
POINT SEVERE CHANCES LOOK MINIMAL GIVEN MODERATE INSTABILITY AND
FAIRLY WEAK SHEAR. ALSO DOES NOT APPEAR CONVECTION ORGANIZED
ENOUGH FOR MUCH OF A FLASH FLOOD THREAT...NOR IS THERE ANY UPSLOPE
COMPONENT ALONG BLUE RIDGE AND AREAS OF CONVECTION SHOULD BE
MOVING QUICKLY WITH FRONTAL BOUNDARY. TEMPERATURES IN MOST PLACES
SHOULD BE ON COOL SIDE OF GUIDANCE...BUT WILL HAVE TO CONSIDER
POTENTIAL FOR DECENT AMOUNT OF SUN IN THE WEST IF FRONT MOVES
FASTER...EXCEPT FOR FAR WESTERN SLOPES WHERE CLOUDS AND A FEW
SHOWERS COULD LINGER. SO SOME SPOTS IN WESTERN VALLEYS MAY WARM TO
AS MUCH OR HIGHER THAN PIEDMONT...DEPENDING ON TIMING OF
FRONT...LINGERING PRECIP EAST IN AFTERNOON...AND SUNSHINE IN WEST.
SOMEWHAT DRIER AIR BUT NOT NECESSARILY MUCH COOLER AIRMASS BEHIND
FRONT FOR THURS NIGHT INTO FRIDAY. DOWNSLOPE AND MORE SUN SHOULD
CONTRIBUTE TO WARMER TEMPS...ESPECIALLY OUT EAST BUT PROBABLY
EVERYWHERE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 420 AM EDT WEDNESDAY...
ANOTHER FRONT TO SLIDE DOWN FROM NORTH BY END OF WEEKEND WITH WAVE
POSSIBLY BRINGING SHOWERS IN AHEAD OF IT AS EARLY AS SATURDAY
MORNING. TRICKY TO KNOW THIS FAR OUT JUST HOW MUCH THIS FRONT WILL
SAG SOUTH ACROSS FCST AREA...AND WHETHER BY LATE SUNDAY IT WILL
ACTUALLY DROP SOUTH OF THE AREA OR STALL ACROSS US...BUT LATEST
TRENDS SUGGEST IT MAY TRY TO MAKE IT THROUGH THUS MADE SOME
ADJUSTMENTS TO POPS BASED ON THIS. TEMPS LIKELY AT OR JUST BELOW
NORMAL THROUGH WEEKEND AND INTO EARLY NEXT WEEK WITH THE EFFECTS OF
THIS FRONTAL BOUNDARY PASSING THROUGH...AND THEN THE POSSIBILITY OF
LIFTING BACK ACROSS US AS A WARM FRONT BRINGING PRECIP CHANCES
AROUND WITH ONLY A SHORT BREAK...IF ANY...LATE SUNDAY INTO MONDAY.
MUCH UNCERTAINTY AT THIS TIME HOWEVER.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 745 AM EDT WEDNESDAY...
-RA CONTINUED TO SPREAD ACROSS THE CWA FROM W-E WITH MID/HIGH VFR
CIGS. HAVE YET TO SEE ANY CLOUDS MUCH BELOW 050 ANYWHERE...MOST
AOA 080. VSBYS MOSTLY VFR WITH PCPN FALLING FROM HIGH BASED CIGS
WITH SPOTTY GROUND FOG LWB/LYH/BCB. EXPECT WIDESPREAD -RA TO
CONTINUE TO OVERSPREAD THE AREA FROM W-E INTO MID- MORNING WITH
MOSTLY VFR TO HIGH END MVFR CIGS...GENERALLY AOA035. AS THE
INSITU WEDGE EVOLVES THROUGH THE DAY...EXPECT CIGS TO LOWER TOWARD
MVFR TOWARD EVENING AND ESPECIALLY TOWARD 06Z. MODELS HINT THAT
BULK OF PCPN MAY PASS THROUGH THE CWA IN THE 12Z-20Z TIME
FRAME...MOVING EAST OF THE CWA AFT 20Z. AM CONCERNED THAT THERE
MAY BE -DZ OVERNIGHT IN THE LYH/ROA/BCB AREA...WITH ATTENDING
LOWER VSBYS AS A RESULT. OCCASIONAL MVFR VSBYS CAN BE EXPECTED
THROUGH THE DAYTIME IN -RA BR. WINDS FAVORING A SSE-SSW DIRECTION
WITH SPEEDS MOSTLY AOB 5KTS. HAVE REMOVED ALL MENTION OF TSRA AS
GFS AT LEAST SHOWS NEAR ZERO INSTABILITY TODAY AND WITH AN INSITU
WEDGE AND EXTENSIVE CLOUD COVER/LIGHT PCPN...WOULD NOT EXPECT
ENOUGH INSTABILITY TO BE REALIZED FOR TSRA. IF THERE WERE...ONLY
DAN WOULD SEEM TO HAVE THE POTENTIAL FOR SUCH.
MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH 00Z...THEN MEDIUM
CONFIDENCE.
MEDIUM CONFIDENCE IN VSBYS THROUGH TAF VALID PERIOD.
HIGH CONFIDENCE IN WIND SPD THROUGH TAF VALID PERIOD.
MEDIUM CONFIDENCE IN WIND DIR THROUGH TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN LITTLE TO NO THUNDER AT TAF SITES
THROUGH TAF VALID PERIOD.
EXTENDED AVIATION DISCUSSION...
COLD FRONT ARRIVES THURSDAY WITH POTENTIAL FOR DEEPER CONVECTION
ESPCLY EAST OF THE BLUE RIDGE THURSDAY AFTERNOON. THIS FRONT WILL
PUSH SOUTHEAST OF US THURSDAY NIGHT WITH VFR RETURNING...OUTSIDE
FOG IN THE MORNINGS AT TYPICAL SITES KLWB/KBCB...AND MAYBE
KLYH/KDAN GIVEN WET GROUND.
ANOTHER FRONT ARRIVES SOMETIME THIS WEEKEND AND COULD BRING
SHOWERS AND STORMS...WITH SUB-VFR AT TIMES.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...RAB
NEAR TERM...DS/NP/RAB
SHORT TERM...SK
LONG TERM...RCS/SK
AVIATION...JH/RAB