Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/23/15
AREA FORECAST DISCUSSION...UPDATE
NWS PHOENIX AZ
1020 AM MST FRI AUG 21 2015
.UPDATE...
AVIATION DISCUSSION.
&&
.SYNOPSIS...
THUNDERSTORMS WILL GENERALLY REMAIN CONFINED TO THE HIGHER TERRAIN
OF SOUTHERN AND EASTERN ARIZONA THROUGH THE WEEKEND. HIGH PRESSURE
WILL SETTLE ACROSS THE FOUR CORNERS MONDAY...RESULTING IN BETTER
RAIN CHANCES ACROSS THE LOWER DESERTS. DRIER CONDITIONS WILL RETURN
BY MIDWEEK ALONG WITH NEAR TO ABOVE NORMAL TEMPERATURES.
&&
.DISCUSSION...
A SHEARING SHORTWAVE WAS STILL EVIDENT OVER FAR SERN ARIZONA/SW NEW
MEXICO ON MORNING WV IMAGERY...WITH FLOW OTHERWISE BACKING TO WLY IN
THE MIDLEVELS THROUGH THE FORECAST AREA. RATHER EXTENSIVE ACCAS
CONTINUED TO PERCOLATE FROM ERN PIMA THROUGH GILA COUNTY IN
ASSOCIATION WITH A SLUG OF MOISTURE IN THE H8-H7 LAYER TRAPPED BELOW
A WEAK ELEVATED CAPPED LAYER. HOWEVER...THE MOST NOTABLE FEATURES IN
12Z SOUNDING DATA IS RICH MOISTURE AVAILABILITY IN THE BOUNDARY
LAYER WITH KPSR DATA MEASURING 11-12 G/KG IN THE SFC-H7 LAYER...AND
KTWC SAMPLING AN IMPRESSIVE 14-15 G/KG IN A SFC-750MB LAYER.
AS A RESULT...LATEST MESOANALYSIS ESTIMATES MLCAPES IN THE SERN
QUARTER OF ARIZONA ALREADY ECLIPSING THE 1500-2000 J/KG
RANGE...ALBEIT WITH CINH STILL PRESENT. DESPITE THESE EXCESSIVE
LEVELS OF INSTABILITY...THERE IS LITTLE TO NOTHING EVIDENT IN
SATELLITE IMAGERY THAT COULD BE TERMED AS A LIFTING MECHANISM...AND
THE FACT THAT THE ACCAS TURRETS HAVE NOT EXPERIENCED UPSCALE GROWTH
SUGGEST LARGER SCALE SUBSIDENCE STILL PREDOMINATES ACROSS THE
REGION. THEREFORE...WITH STILL ONLY LIMITED SUPPORT FOR HIGH
RESOLUTION ENSEMBLE DATA...MADE VERY LITTLE CHANGE TO POPS THE
REMAINDER OF THE DAY. HOWEVER...AM STILL CONCERNED DESPITE THE LOWER
CONFIDENCE GIVEN THE POTENTIAL LARGE IMPACTS GIVEN THE HIGH
INSTABILITY VALUES. WILL CONTINUE TO EVALUATE CONVECTIVE POTENTIAL
AND COVERAGE THROUGH THE AFTERNOON.
&&
.PREVIOUS DISCUSSION...
/502 AM MST FRI AUG 21 2015/
AN ANTICYCLONE IN THE MID AND UPPER LEVELS REMAINS POSITIONED OFF
THE BAJA PENINSULA...RESULTING IN A WESTERLY COMPONENT TO THE FLOW.
AT THE SURFACE...YUMA VWP SUGGESTS THAT A SHALLOW GULF SURGE IS
TAKING PLACE ACROSS SOUTHWESTERN AZ. DEWPOINTS NEAR YUMA AND ACROSS
THE IMPERIAL VALLEY HAVE RESPONDED...INCREASING INTO THE MID TO UPPER
70S EARLY THIS MORNING. FURTHER EAST ACROSS THE LOWER DESERTS OF
SOUTH-CENTRAL AZ...AN INFLUX OF MOISTURE IS ALSO ANTICIPATED THIS
MORNING...BUT TO A LESSER DEGREE.
SOME EARLIER WRF-BASED GUIDANCE INDICATED THAT SHOWERS AND
THUNDERSTORMS WOULD DEVELOP THIS MORNING ACROSS PORTIONS OF THE
LOWER DESERTS. HOWEVER...THE LATEST LOCAL WRFS AND U OF ARIZONA WRFS
HAVE BACKED OFF CONSIDERABLY AND DEPICT CONVECTION BEING MOST
CONCENTRATED ACROSS THE HIGHER TERRAIN SOUTH AND EAST OF PHOENIX THIS
AFTERNOON. SEVERAL RUNS OF THE HRRR HAVE ALSO DISMISSED THE
POSSIBILITY OF CONVECTION STARTING EARLY THIS MORNING...THOUGH CAPES
ABOVE 1000 J/KG SHOULD CERTAINLY SUPPORT DEVELOPMENT BY EARLY
AFTERNOON. LACK OF A TRIGGER IN THE UPPER LEVELS ALONG WITH WEAK
WESTERLY FLOW POINT TO TERRAIN- BASED CONVERGENCE AS THE PRIMARY
LIFTING MECHANISM. NEVERTHELESS...THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS IN THE PHOENIX AREA...THOUGH THE GREATER LIKELIHOOD IS
FOR AREAS OF BLOWING DUST.
MEAN FLOW WILL BECOME MORE WESTERLY SATURDAY AS THE ANTICYCLONE
DRIFTS NORTHWARD. THIS WILL AGAIN CONFINE THUNDERSTORMS MAINLY TO THE
HIGHER TERRAIN EAST OF PHOENIX. MORE OF THE SAME FOR SUNDAY AS THE
HIGH DRIFTS OVERHEAD.
CONDITIONS WILL BECOME SOMEWHAT MORE FAVORABLE FOR PRECIPITATION
EARLY NEXT WEEK AS THE MONSOON HIGH BECOMES REESTABLISHED ACROSS THE
FOUR CORNERS. INCREASING EASTERLY COMPONENT TO THE FLOW GENERALLY
FAVORS HIGHER CHANCES OF THUNDERSTORMS. HOWEVER...MODEL CROSS
SECTIONS INDICATE THAT ABUNDANT MOISTURE IN THE MID AND UPPER LEVELS
MAY RESULT IN CONSIDERABLE CLOUDINESS AND ULTIMATELY A DECREASE IN
INSTABILITY AND THE POTENTIAL FOR THUNDERSTORMS ACROSS THE AREA.
OPERATIONAL GFS AND ECMWF ALSO SUGGEST THE PRESENCE OF AN INVERTED
TROUGH ACROSS NORTHERN SONORA...THOUGH DIFFERENCES IN THE STRENGTH
AND TIMING OF THIS FEATURE ARE APPARENT.
GENERAL CONSENSUS AMONG THE MODELS FOR NEXT WEEK IS THAT THE MONSOON
HIGH WILL DRIFT EASTWARD AND SOUTHWARD. FLOW WILL GRADUALLY BECOME
SOUTHWESTERLY AGAIN...FAVORING THE HIGHER TERRAIN FOR CONVECTION.
TEMPERATURES AT OR ABOVE NORMAL ARE EXPECTED THROUGH THE EXTENDED.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL
A RATHER MESSY EASTERLY FLOW ACROSS THE PHX AREA CONTINUES LATE THIS
MORNING. FULLY EXPECT WESTERLY FLOW TO DEVELOP OVER THE NEXT FEW
HOURS...APPEARING NOT AS STRONG/GUSTY AS EARLIER. ONE THING TO WATCH
IS A FEW THUNDERSHOWERS WELL E OF THE PHX AREA. ATMOSPHERE DOES HAVE
A DECENT AMOUNT OF INSTABILITY TODAY BUT NO CLEAR MECHANISM TO
RELEASE IT. SHOULD STORMS OVER SE AZ DEVELOP BETTER THROUGH THE
DAY...MAY CONTEND WITH NEARBY TS AND OUTFLOW FOR PHX AREA TERMINALS.
MOST LIKELY OUTCOME IS A SUNNY AND QUIET DAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
TYPICAL DIURNAL WIND PATTERNS WITH CLEAR SKIES THROUGH AT LEAST 00Z
SUNDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
MONSOON MOISTURE LEVELS AND HUMIDITIES WILL PERSIST THROUGH MIDWEEK.
STORM CHANCES WILL CONTINUE FOR THE HIGHER TERRAIN LOCALES FOR
SUNDAY BEFORE EXPANDING INTO THE LOWER DESERT ELEVATIONS BY THE
EARLY WORK WEEK AS SOME UPPER LEVEL DISTURBANCES PASS THROUGH THE
AREA AND SUPPORT THE POTENTIAL FOR MORE WIDESPREAD STORM
DEVELOPMENT. DAYTIME HUMIDITIES WILL RANGE FROM THE 20 TO 30 PERCENT
RANGE WHILE MAKING GOOD OVERNIGHT RECOVERIES. OUTSIDE OF
THUNDERSTORM OUTFLOW AND VICINITY WINDS...SFC WINDS TO MAINTAIN
DAYTIME HEADINGS 10 TO 20 MPH WHILE BECOMING DOWN DRAINAGE/DOWN
VALLEY IN THE OVERNIGHTS. A SLIGHT DRAW DOWN OF MONSOON MOISTURE AND
INTRUSION OF WESTERLY FLOW ALOFT WILL RELEGATE STORM CHANCES BACK
ACROSS EASTERN AZ FOR THE LATTER PART OF THE WEEK...WHILE
TEMPERATURES ALSO BEGIN TO WARM TO ABOVE NORMAL VALUES.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MO/HIRSCH
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
1004 AM MST FRI AUG 21 2015
.SYNOPSIS...SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE TO
INCREASE THROUGH THE COMING WEEKEND WITH A MORE TYPICAL MONSOON
PATTERN EXPECTED INTO EARLY NEXT WEEK. THE INCREASED MOISTURE WILL
ALSO KEEP DAYTIME TEMPERATURES CLOSER TO SEASONAL AVERAGES FRIDAY
INTO EARLY NEXT WEEK.
&&
.DISCUSSION...THE TUCSON MORNING UPPER-AIR SOUNDING INDICATED A
RATHER MOIST AND UNSTABLE AIRMASS IN PLACE ACROSS THE AREA. IN
FACT...A FEW SHOWERS AND THUNDERSTORMS WERE ALREADY REDEVELOPING IN
COCHISE COUNTY AS OF 10 AM MST. LATEST HRRR SOLUTIONS SUGGESTED
ANOTHER ACTIVE THUNDERSTORM DAY INSTORE FOR SOUTHEAST ARIZONA TODAY.
RAIN CHANCES IN THE CURRENT FORECAST STILL LOOKED ON TRACK...SO NO
PLANS TO UPDATE THE FORECAST AT THIS TIME. PLEASE REFER THE
ADDITIONAL SECTIONS FOR MORE DETAILS.
&&
.AVIATION...VALID THRU 22/18Z.
SKC-FEW HIGH CIRRUS CLOUDS AT 20-25K FT...THEN SCT-BKN CLOUDS AT 7-
11K FT AGL REDEVELOPING THIS AFTERNOON...ALONG WITH ISOLATED TO
SCATTERED SHRA/TSRA. BRIEF MVFR CONDITIONS...ALONG WITH STRONG GUSTY
WINDS POSSIBLE IN AN AROUND SHRA/TSRA. OTHERWISE...WINDS WILL
GENERALLY BE LIGHT AND TERRAIN DRIVEN. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOISTURE WILL CONTINUE TO INCREASE WITH ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED THIS AFTERNOON AND
EVENING WITH AN EMPHASIS ON AREAS FROM TUCSON AND POINTS EASTWARD.
THEREAFTER...MOISTURE AND THUNDERSTORMS CHANCES WILL INCREASE AND
SPREAD THROUGHOUT SOUTHEAST ARIZONA THROUGH THE WEEKEND INTO EARLY
NEXT WEEK. EXPECT A DECREASE IN SHOWER AND THUNDERSTORMS DURING THE
MIDDLE TO LATTER PART OF NEXT WEEK. WINDS WILL BE TYPICAL FOR MID
AUGUST AND GENERALLY LESS THAN 15 MPH WITH AFTERNOON GUSTINESS...
ESPECIALLY IN THE GILA RIVER VALLEY.
&&
.PREV DISCUSSION...THERE IS A VERY WEAK FEATURE OVER NORTHERN BAJA
THAT SHOULD MOVE SLOWLY EASTWARD AND POTENTIALLY HELP OUT ALONG OR
SOUTH OF THE BORDER LATE TODAY BUT IT IS MUCH LESS SIGNIFICANT THAN
WHAT HELPED YESTERDAYS CONVECTION. SO OVERALL WITH THE INSTABILITY
AND MOISTURE THAT WE HAVE WOULD EXPECT CONVECTION TO FIRE UP OVER
HIGHER TERRAIN EARLY THIS AFTERNOON ACROSS THE EASTERN TWO THIRDS OF
THE AREA THEN SPREAD FROM THERE DUE TO OUTFLOWS. WHAT WILL BE
INTERESTING IS STORM MOTION AS THE UPPER LEVEL WINDS ARE LIGHTER
THAN YESTERDAY SO STORM MOTION WILL BE SLOWER AND LIKELY A BIT TO
THE EAST ALTHOUGH OUTFLOWS WILL LIKELY DRIVE THE MOVEMENT OF SOME
STORMS IN THIS LIGHT FLOW. WITH 102 AS A HIGH THURSDAY I WENT AHEAD
AND BUMPED TODAYS TEMPS A DEGREE OR TWO FROM WHAT WAS IN THERE. IF
THE CONVECTION IS SLOWER TO DEVELOP WILL LIKELY BE A BIT HIGHER YET.
ON SATURDAY THE UPPER HIGH NOW JUST TO OUR SW WILL BE MOVING EAST
ACROSS THE AREA THROUGH THE DAY. WILL STILL HAVE A GOOD AMOUNT OF
MOISTURE HOWEVER MID LEVEL TEMPS WILL BE A BIT WARMER FOR LESS
INSTABILITY. SHOULD STILL SEE CONVECTION DEVELOP JUST NOT EXPECTING
AN ABUNDANCE OF IT AND WILL LIKELY BE FOCUSED ON THE TERRAIN FROM
TUCSON EASTWARD.
IT POTENTIALLY BECOMES A BIT MORE INTERESTING AFTER THAT AS THE HIGH
CONTINUES EAST TO NEW MEXICO/TEXAS BY SUNDAY. GUIDANCE CONTINUES TO
SHOW A DISTURBANCE OVER MEXICO MOVING WNW ACROSS THE AREA SUNDAY
INTO MONDAY. VARIOUS MODELS DIFFER ON THE TIMING WITH THE GFS BEING
THE QUICKER OF THE BUNCH ON THE LATEST RUN. WHEN THIS DOES PASS IT
SHOULD RAMP UP THE CONVECTION AND AT THIS TIME THE MOST LIKELY TIME
WOULD BE LATE SUNDAY INTO MONDAY. I RAISED POPS A BIT THROUGH THIS
TIME FRAME TO TRY TO CAPTURE THIS BUT WE WILL NEED TO KEEP AN EYE ON
THIS AS THE TIME APPROACHES FOR MORE DETAILS AS THE BULK OF IT COULD
SLIDE BY JUST TO OUR SOUTH DEPENDING ON THE LOCATION OF THE
EAST/WEST RIDGE AXIS. SUNDAY AND MONDAY LIKELY THE COOLEST DAYS OF
THE FORECAST PERIOD WITH HIGHS A BIT BELOW NORMAL.
TUESDAY AND WEDNESDAY THE UPPER HIGH IS IN A PRETTY GOOD POSITION
FOR CONVECTIVE ACTIVITY OVER THE CWA AND HAVE LEFT THE POPS AS THEY
WERE WHICH IS ABOUT 5-10 POINTS ABOVE CLIMO. WITH A BIT MORE
SUNSHINE BUMPED TEMPS BACK UP A BIT. SHOULD BE ABLE TO ADD A FEW
MORE 100+ DEGREE DAYS TO THE TALLY FOR TUCSON.
THURSDAY ONWARD THE UPPER HIGH IS PROGGED TO SLIDE RIGHT OVER THE
AREA WHICH WOULD ACT TO SHUT OFF THE MOISTURE FLOW AND SUPPRESS
CONVECTION WHILE ALSO ALLOWING FOR ABOVE NORMAL TEMPERATURES.
TWEAKED THE GRIDS WITH THAT IN MIND...SLIGHTLY DRIER AND WARMER.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
945 AM MST FRI AUG 21 2015
.SYNOPSIS...
THUNDERSTORMS WILL GENERALLY REMAIN CONFINED TO THE HIGHER TERRAIN
OF SOUTHERN AND EASTERN ARIZONA THROUGH THE WEEKEND. HIGH PRESSURE
WILL SETTLE ACROSS THE FOUR CORNERS MONDAY...RESULTING IN BETTER
RAIN CHANCES ACROSS THE LOWER DESERTS. DRIER CONDITIONS WILL RETURN
BY MIDWEEK ALONG WITH NEAR TO ABOVE NORMAL TEMPERATURES.
&&
.DISCUSSION...
A SHEARING SHORTWAVE WAS STILL EVIDENT OVER FAR SERN ARIZONA/SW NEW
MEXICO ON MORNING WV IMAGERY...WITH FLOW OTHERWISE BACKING TO WLY IN
THE MIDLEVELS THROUGH THE FORECAST AREA. RATHER EXTENSIVE ACCAS
CONTINUED TO PERCOLATE FROM ERN PIMA THROUGH GILA COUNTY IN
ASSOCIATION WITH A SLUG OF MOISTURE IN THE H8-H7 LAYER TRAPPED BELOW
A WEAK ELEVATED CAPPED LAYER. HOWEVER...THE MOST NOTABLE FEATURES IN
12Z SOUNDING DATA IS RICH MOISTURE AVAILABILITY IN THE BOUNDARY
LAYER WITH KPSR DATA MEASURING 11-12 G/KG IN THE SFC-H7 LAYER...AND
KTWC SAMPLING AN IMPRESSIVE 14-15 G/KG IN A SFC-750MB LAYER.
AS A RESULT...LATEST MESOANALYSIS ESTIMATES MLCAPES IN THE SERN
QUARTER OF ARIZONA ALREADY ECLIPSING THE 1500-2000 J/KG
RANGE...ALBEIT WITH CINH STILL PRESENT. DESPITE THESE EXCESSIVE
LEVELS OF INSTABILITY...THERE IS LITTLE TO NOTHING EVIDENT IN
SATELLITE IMAGERY THAT COULD BE TERMED AS A LIFTING MECHANISM...AND
THE FACT THAT THE ACCAS TURRETS HAVE NOT EXPERIENCED UPSCALE GROWTH
SUGGEST LARGER SCALE SUBSIDENCE STILL PREDOMINATES ACROSS THE
REGION. THEREFORE...WITH STILL ONLY LIMITED SUPPORT FOR HIGH
RESOLUTION ENSEMBLE DATA...MADE VERY LITTLE CHANGE TO POPS THE
REMAINDER OF THE DAY. HOWEVER...AM STILL CONCERNED DESPITE THE LOWER
CONFIDENCE GIVEN THE POTENTIAL LARGE IMPACTS GIVEN THE HIGH
INSTABILITY VALUES. WILL CONTINUE TO EVALUATE CONVECTIVE POTENTIAL
AND COVERAGE THROUGH THE AFTERNOON.
&&
.PREVIOUS DISCUSSION...
/502 AM MST FRI AUG 21 2015/
AN ANTICYCLONE IN THE MID AND UPPER LEVELS REMAINS POSITIONED OFF
THE BAJA PENINSULA...RESULTING IN A WESTERLY COMPONENT TO THE FLOW.
AT THE SURFACE...YUMA VWP SUGGESTS THAT A SHALLOW GULF SURGE IS
TAKING PLACE ACROSS SOUTHWESTERN AZ. DEWPOINTS NEAR YUMA AND ACROSS
THE IMPERIAL VALLEY HAVE RESPONDED...INCREASING INTO THE MID TO UPPER
70S EARLY THIS MORNING. FURTHER EAST ACROSS THE LOWER DESERTS OF
SOUTH-CENTRAL AZ...AN INFLUX OF MOISTURE IS ALSO ANTICIPATED THIS
MORNING...BUT TO A LESSER DEGREE.
SOME EARLIER WRF-BASED GUIDANCE INDICATED THAT SHOWERS AND
THUNDERSTORMS WOULD DEVELOP THIS MORNING ACROSS PORTIONS OF THE
LOWER DESERTS. HOWEVER...THE LATEST LOCAL WRFS AND U OF ARIZONA WRFS
HAVE BACKED OFF CONSIDERABLY AND DEPICT CONVECTION BEING MOST
CONCENTRATED ACROSS THE HIGHER TERRAIN SOUTH AND EAST OF PHOENIX THIS
AFTERNOON. SEVERAL RUNS OF THE HRRR HAVE ALSO DISMISSED THE
POSSIBILITY OF CONVECTION STARTING EARLY THIS MORNING...THOUGH CAPES
ABOVE 1000 J/KG SHOULD CERTAINLY SUPPORT DEVELOPMENT BY EARLY
AFTERNOON. LACK OF A TRIGGER IN THE UPPER LEVELS ALONG WITH WEAK
WESTERLY FLOW POINT TO TERRAIN- BASED CONVERGENCE AS THE PRIMARY
LIFTING MECHANISM. NEVERTHELESS...THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS IN THE PHOENIX AREA...THOUGH THE GREATER LIKELIHOOD IS
FOR AREAS OF BLOWING DUST.
MEAN FLOW WILL BECOME MORE WESTERLY SATURDAY AS THE ANTICYCLONE
DRIFTS NORTHWARD. THIS WILL AGAIN CONFINE THUNDERSTORMS MAINLY TO THE
HIGHER TERRAIN EAST OF PHOENIX. MORE OF THE SAME FOR SUNDAY AS THE
HIGH DRIFTS OVERHEAD.
CONDITIONS WILL BECOME SOMEWHAT MORE FAVORABLE FOR PRECIPITATION
EARLY NEXT WEEK AS THE MONSOON HIGH BECOMES REESTABLISHED ACROSS THE
FOUR CORNERS. INCREASING EASTERLY COMPONENT TO THE FLOW GENERALLY
FAVORS HIGHER CHANCES OF THUNDERSTORMS. HOWEVER...MODEL CROSS
SECTIONS INDICATE THAT ABUNDANT MOISTURE IN THE MID AND UPPER LEVELS
MAY RESULT IN CONSIDERABLE CLOUDINESS AND ULTIMATELY A DECREASE IN
INSTABILITY AND THE POTENTIAL FOR THUNDERSTORMS ACROSS THE AREA.
OPERATIONAL GFS AND ECMWF ALSO SUGGEST THE PRESENCE OF AN INVERTED
TROUGH ACROSS NORTHERN SONORA...THOUGH DIFFERENCES IN THE STRENGTH
AND TIMING OF THIS FEATURE ARE APPARENT.
GENERAL CONSENSUS AMONG THE MODELS FOR NEXT WEEK IS THAT THE MONSOON
HIGH WILL DRIFT EASTWARD AND SOUTHWARD. FLOW WILL GRADUALLY BECOME
SOUTHWESTERLY AGAIN...FAVORING THE HIGHER TERRAIN FOR CONVECTION.
TEMPERATURES AT OR ABOVE NORMAL ARE EXPECTED THROUGH THE EXTENDED.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
EARLY AM SCT-BKN CLOUDS BETWEEN PHX AND CGZ WILL SETTLE OUT TO FEW-
SCT MID-LEVEL CLOUDS FOR THE AFTN...WITH SKIES REMAINING MOSTLY
CLEAR FOR THE WESTERN TERMINALS OF BLH AND IPL. S-SE AM WINDS TO
PREVAIL FOR THE TERMINALS SAVE FOR KPHX...WHICH WILL MAINTAIN SUBTLE
W-NW HEADINGS WITH PERIODS OF VRB. AFTN WINDS TO BECOME S-SW FOR THE
PHX AREA TERMINALS...WITH PERIODS OF 20KT GUSTINESS. ISO TS SHOULD
FORM WELL EAST AND SOUTH OF THE PHX AREA...WITH VERY REMOTE CHANCES
OF OUTFLOW RELATED IMPACTS INTO KIWA DURING THE EVENING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
MONSOON MOISTURE LEVELS AND HUMIDITIES WILL PERSIST THROUGH MIDWEEK.
STORM CHANCES WILL CONTINUE FOR THE HIGHER TERRAIN LOCALES FOR
SUNDAY BEFORE EXPANDING INTO THE LOWER DESERT ELEVATIONS BY THE
EARLY WORK WEEK AS SOME UPPER LEVEL DISTURBANCES PASS THROUGH THE
AREA AND SUPPORT THE POTENTIAL FOR MORE WIDESPREAD STORM
DEVELOPMENT. DAYTIME HUMIDITIES WILL RANGE FROM THE 20 TO 30 PERCENT
RANGE WHILE MAKING GOOD OVERNIGHT RECOVERIES. OUTSIDE OF
THUNDERSTORM OUTFLOW AND VICINITY WINDS...SFC WINDS TO MAINTAIN
DAYTIME HEADINGS 10 TO 20 MPH WHILE BECOMING DOWN DRAINAGE/DOWN
VALLEY IN THE OVERNIGHTS. A SLIGHT DRAW DOWN OF MONSOON MOISTURE AND
INTRUSION OF WESTERLY FLOW ALOFT WILL RELEGATE STORM CHANCES BACK
ACROSS EASTERN AZ FOR THE LATTER PART OF THE WEEK...WHILE
TEMPERATURES ALSO BEGIN TO WARM TO ABOVE NORMAL VALUES.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MO/HIRSCH
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
502 AM MST FRI AUG 21 2015
.UPDATE...TO AVIATION AND FIRE WEATHER DISCUSSIONS...
&&
.SYNOPSIS...
THUNDERSTORMS WILL GENERALLY REMAIN CONFINED TO THE HIGHER TERRAIN OF
SOUTHERN AND EASTERN ARIZONA THROUGH THE WEEKEND. THE MONSOON HIGH
WILL SETTLE ACROSS THE FOUR CORNERS MONDAY...RESULTING IN BETTER RAIN
CHANCES ACROSS THE LOWER DESERTS. DRIER CONDITIONS WILL RETURN BY
MIDWEEK ALONG WITH NEAR TO ABOVE NORMAL TEMPERATURES.
&&
.DISCUSSION...
AN ANTICYCLONE IN THE MID AND UPPER LEVELS REMAINS POSITIONED OFF
THE BAJA PENINSULA...RESULTING IN A WESTERLY COMPONENT TO THE FLOW.
AT THE SURFACE...YUMA VWP SUGGESTS THAT A SHALLOW GULF SURGE IS
TAKING PLACE ACROSS SOUTHWESTERN AZ. DEWPOINTS NEAR YUMA AND ACROSS
THE IMPERIAL VALLEY HAVE RESPONDED...INCREASING INTO THE MID TO UPPER
70S EARLY THIS MORNING. FURTHER EAST ACROSS THE LOWER DESERTS OF
SOUTH-CENTRAL AZ...AN INFLUX OF MOISTURE IS ALSO ANTICIPATED THIS
MORNING...BUT TO A LESSER DEGREE.
SOME EARLIER WRF-BASED GUIDANCE INDICATED THAT SHOWERS AND
THUNDERSTORMS WOULD DEVELOP THIS MORNING ACROSS PORTIONS OF THE
LOWER DESERTS. HOWEVER...THE LATEST LOCAL WRFS AND U OF ARIZONA WRFS
HAVE BACKED OFF CONSIDERABLY AND DEPICT CONVECTION BEING MOST
CONCENTRATED ACROSS THE HIGHER TERRAIN SOUTH AND EAST OF PHOENIX THIS
AFTERNOON. SEVERAL RUNS OF THE HRRR HAVE ALSO DISMISSED THE
POSSIBILITY OF CONVECTION STARTING EARLY THIS MORNING...THOUGH CAPES
ABOVE 1000 J/KG SHOULD CERTAINLY SUPPORT DEVELOPMENT BY EARLY
AFTERNOON. LACK OF A TRIGGER IN THE UPPER LEVELS ALONG WITH WEAK
WESTERLY FLOW POINT TO TERRAIN- BASED CONVERGENCE AS THE PRIMARY
LIFTING MECHANISM. NEVERTHELESS...THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS IN THE PHOENIX AREA...THOUGH THE GREATER LIKELIHOOD IS
FOR AREAS OF BLOWING DUST.
MEAN FLOW WILL BECOME MORE WESTERLY SATURDAY AS THE ANTICYCLONE
DRIFTS NORTHWARD. THIS WILL AGAIN CONFINE THUNDERSTORMS MAINLY TO THE
HIGHER TERRAIN EAST OF PHOENIX. MORE OF THE SAME FOR SUNDAY AS THE
HIGH DRIFTS OVERHEAD.
CONDITIONS WILL BECOME SOMEWHAT MORE FAVORABLE FOR PRECIPITATION
EARLY NEXT WEEK AS THE MONSOON HIGH BECOMES REESTABLISHED ACROSS THE
FOUR CORNERS. INCREASING EASTERLY COMPONENT TO THE FLOW GENERALLY
FAVORS HIGHER CHANCES OF THUNDERSTORMS. HOWEVER...MODEL CROSS
SECTIONS INDICATE THAT ABUNDANT MOISTURE IN THE MID AND UPPER LEVELS
MAY RESULT IN CONSIDERABLE CLOUDINESS AND ULTIMATELY A DECREASE IN
INSTABILITY AND THE POTENTIAL FOR THUNDERSTORMS ACROSS THE AREA.
OPERATIONAL GFS AND ECMWF ALSO SUGGEST THE PRESENCE OF AN INVERTED
TROUGH ACROSS NORTHERN SONORA...THOUGH DIFFERENCES IN THE STRENGTH
AND TIMING OF THIS FEATURE ARE APPARENT.
GENERAL CONSENSUS AMONG THE MODELS FOR NEXT WEEK IS THAT THE MONSOON
HIGH WILL DRIFT EASTWARD AND SOUTHWARD. FLOW WILL GRADUALLY BECOME
SOUTHWESTERLY AGAIN...FAVORING THE HIGHER TERRAIN FOR CONVECTION.
TEMPERATURES AT OR ABOVE NORMAL ARE EXPECTED THROUGH THE EXTENDED.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
EARLY AM SCT-BKN CLOUDS BETWEEN PHX AND CGZ WILL SETTLE OUT TO FEW-
SCT MID-LEVEL CLOUDS FOR THE AFTN...WITH SKIES REMAINING MOSTLY
CLEAR FOR THE WESTERN TERMINALS OF BLH AND IPL. S-SE AM WINDS TO
PREVAIL FOR THE TERMINALS SAVE FOR KPHX...WHICH WILL MAINTAIN SUBTLE
W-NW HEADINGS WITH PERIODS OF VRB. AFTN WINDS TO BECOME S-SW FOR THE
PHX AREA TERMINALS...WITH PERIODS OF 20KT GUSTINESS. ISO TS SHOULD
FORM WELL EAST AND SOUTH OF THE PHX AREA...WITH VERY REMOTE CHANCES
OF OUTFLOW RELATED IMPACTS INTO KIWA DURING THE EVENING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...
MONSOON MOISTURE LEVELS AND HUMIDITIES WILL PERSIST THROUGH MIDWEEK.
STORM CHANCES WILL CONTINUE FOR THE HIGHER TERRAIN LOCALES FOR
SUNDAY BEFORE EXPANDING INTO THE LOWER DESERT ELEVATIONS BY THE
EARLY WORK WEEK AS SOME UPPER LEVEL DISTURBANCES PASS THROUGH THE
AREA AND SUPPORT THE POTENTIAL FOR MORE WIDESPREAD STORM
DEVELOPMENT. DAYTIME HUMIDITIES WILL RANGE FROM THE 20 TO 30 PERCENT
RANGE WHILE MAKING GOOD OVERNIGHT RECOVERIES. OUTSIDE OF
THUNDERSTORM OUTFLOW AND VICINITY WINDS...SFC WINDS TO MAINTAIN
DAYTIME HEADINGS 10 TO 20 MPH WHILE BECOMING DOWN DRAINAGE/DOWN
VALLEY IN THE OVERNIGHTS. A SLIGHT DRAW DOWN OF MONSOON MOISTURE AND
INTRUSION OF WESTERLY FLOW ALOFT WILL RELEGATE STORM CHANCES BACK
ACROSS EASTERN AZ FOR THE LATTER PART OF THE WEEK...WHILE
TEMPERATURES ALSO BEGIN TO WARM TO ABOVE NORMAL VALUES.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
328 AM MST FRI AUG 21 2015
.SYNOPSIS...
THUNDERSTORMS WILL GENERALLY REMAIN CONFINED TO THE HIGHER TERRAIN OF
SOUTHERN AND EASTERN ARIZONA THROUGH THE WEEKEND. THE MONSOON HIGH
WILL SETTLE ACROSS THE FOUR CORNERS MONDAY...RESULTING IN BETTER RAIN
CHANCES ACROSS THE LOWER DESERTS. DRIER CONDITIONS WILL RETURN BY
MIDWEEK ALONG WITH NEAR TO ABOVE NORMAL TEMPERATURES.
&&
.DISCUSSION...
AN ANTICYCLONE IN THE MID AND UPPER LEVELS REMAINS POSITIONED OFF
THE BAJA PENINSULA...RESULTING IN A WESTERLY COMPONENT TO THE FLOW.
AT THE SURFACE...YUMA VWP SUGGESTS THAT A SHALLOW GULF SURGE IS
TAKING PLACE ACROSS SOUTHWESTERN AZ. DEWPOINTS NEAR YUMA AND ACROSS
THE IMPERIAL VALLEY HAVE RESPONDED...INCREASING INTO THE MID TO UPPER
70S EARLY THIS MORNING. FURTHER EAST ACROSS THE LOWER DESERTS OF
SOUTH-CENTRAL AZ...AN INFLUX OF MOISTURE IS ALSO ANTICIPATED THIS
MORNING...BUT TO A LESSER DEGREE.
SOME EARLIER WRF-BASED GUIDANCE INDICATED THAT SHOWERS AND
THUNDERSTORMS WOULD DEVELOP THIS MORNING ACROSS PORTIONS OF THE
LOWER DESERTS. HOWEVER...THE LATEST LOCAL WRFS AND U OF ARIZONA WRFS
HAVE BACKED OFF CONSIDERABLY AND DEPICT CONVECTION BEING MOST
CONCENTRATED ACROSS THE HIGHER TERRAIN SOUTH AND EAST OF PHOENIX THIS
AFTERNOON. SEVERAL RUNS OF THE HRRR HAVE ALSO DISMISSED THE
POSSIBILITY OF CONVECTION STARTING EARLY THIS MORNING...THOUGH CAPES
ABOVE 1000 J/KG SHOULD CERTAINLY SUPPORT DEVELOPMENT BY EARLY
AFTERNOON. LACK OF A TRIGGER IN THE UPPER LEVELS ALONG WITH WEAK
WESTERLY FLOW POINT TO TERRAIN- BASED CONVERGENCE AS THE PRIMARY
LIFTING MECHANISM. NEVERTHELESS...THERE IS A SLIGHT CHANCE OF
THUNDERSTORMS IN THE PHOENIX AREA...THOUGH THE GREATER LIKELIHOOD IS
FOR AREAS OF BLOWING DUST.
MEAN FLOW WILL BECOME MORE WESTERLY SATURDAY AS THE ANTICYCLONE
DRIFTS NORTHWARD. THIS WILL AGAIN CONFINE THUNDERSTORMS MAINLY TO THE
HIGHER TERRAIN EAST OF PHOENIX. MORE OF THE SAME FOR SUNDAY AS THE
HIGH DRIFTS OVERHEAD.
CONDITIONS WILL BECOME SOMEWHAT MORE FAVORABLE FOR PRECIPITATION
EARLY NEXT WEEK AS THE MONSOON HIGH BECOMES REESTABLISHED ACROSS THE
FOUR CORNERS. INCREASING EASTERLY COMPONENT TO THE FLOW GENERALLY
FAVORS HIGHER CHANCES OF THUNDERSTORMS. HOWEVER...MODEL CROSS
SECTIONS INDICATE THAT ABUNDANT MOISTURE IN THE MID AND UPPER LEVELS
MAY RESULT IN CONSIDERABLE CLOUDINESS AND ULTIMATELY A DECREASE IN
INSTABILITY AND THE POTENTIAL FOR THUNDERSTORMS ACROSS THE AREA.
OPERATIONAL GFS AND ECMWF ALSO SUGGEST THE PRESENCE OF AN INVERTED
TROUGH ACROSS NORTHERN SONORA...THOUGH DIFFERENCES IN THE STRENGTH
AND TIMING OF THIS FEATURE ARE APPARENT.
GENERAL CONSENSUS AMONG THE MODELS FOR NEXT WEEK IS THAT THE MONSOON
HIGH WILL DRIFT EASTWARD AND SOUTHWARD. FLOW WILL GRADUALLY BECOME
SOUTHWESTERLY AGAIN...FAVORING THE HIGHER TERRAIN FOR CONVECTION.
TEMPERATURES AT OR ABOVE NORMAL ARE EXPECTED THROUGH THE EXTENDED.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES AND LIGHT WINDS AT THE TERMINAL SITES EXPECTED
OVERNIGHT THROUGH MID-DAY FRIDAY. ISOLATED THUNDERSTORMS WILL FORM
WELL EAST AND SOUTH OF PHOENIX AREA TERMINALS AFTER 20Z FRIDAY...
WITH SOUTHWEST AZ AND SOUTHEAST CA DESERT SITES REMAINING DRY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
SATURDAY THROUGH WEDNESDAY...
INCREASING MONSOON MOISTURE FROM MEXICO IS EXPECTED THIS PERIOD. A
SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS ARE FORECAST
OVER THE SOUTHERN GILA COUNTY MOUNTAINS THIS WEEKEND. THE CHANCE OF
SHOWERS AND THUNDERSTORMS WILL SPREAD WEST ACROSS MUCH OF SOUTHWEST
AND SOUTH CENTRAL ARIZONA MONDAY THROUGH WEDNESDAY. MINIMUM RELATIVE
HUMIDITY BECOMING 20 TO 30 PERCENT. SOUTH TO SOUTHWEST AFTERNOON
DIURNAL WINDS 10 TO 20 MPH. FAIR RECOVERY OVERNIGHT.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...MEYERS
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
908 AM PDT FRI AUG 21 2015
.Synopsis... Dry weather with near normal temperatures through
early next week. Hazy/smoky conditions will continue in portions
of NorCal.
&&
.Short Term Discussion (Today through Monday)...
The Delta Breeze is still healthy early this morning some stratus
that formed over northeastern Sacramento county, but it won`t last
very long. The short term forecast into Monday will be reasonable
& seasonable. Daytime highs will generally oscillate within 5
degrees of normal. For areas influenced by the Delta Breeze,
daytime highs will be near to slightly below normal while other
areas will be near to slightly above normal. For today, Valley
highs will range upper 80s (near Delta) to upper 90s (near
Redding) while max temps in higher terrain will range in the 70s
(higher elevations of the Sierra) to the upper 80s/low 90s
(foothill locations). Very subtle warming occurs starting Saturday
as ridging strengthens over NorCal.
The main concern in the short term are the hazy/smoky conditions
due to fires that continue to burn, especially the many fires in
Trinity county. The HRRR model showed that smoke particulates
from the Trinity vicinity could move southward today towards
Sacramento area and then curl around as the Delta Breeze moves
northward up the valley. However, the satellite imagery this
morning indicates less smoke than yesterday, with a swath south
and east of Sacramento area and a west to east plume into Redding.
In any case, some degree of haze will be present over the next
several days.
JBB/JClapp
&&
.Extended Discussion (Tuesday through Friday)
Near normal temperatures on Tuesday will be followed by
temperatures trending down through the rest of the week into the
weekend as a cool trough from the Gulf of Alaska approaches. How
quickly this system moves in is still in doubt, as the 00Z GFS and
ECMWF have essentially traded positions from model runs yesterday,
with the GFS now keeping a closed low off the coast and the ECMWF
bringing a quicker moving trough in on Friday. This would bring
the potential for some precipitation into far northern California
late Friday. While the GFS does keep the main low off the coast,
it does have a weak shortwave on Friday afternoon. Have introduced
just a slight chance of rain showers for the northern Coastal
Range for Friday afternoon. Will be watching to see if later model
runs trend closer together and need to expand this later.
Current Global Ensemble Forecast System (GEFS) ensembles and
analogs are pointing towards a cool down for late in the week.
Highs by Friday may stay in the 80s, even over the northern
Sacramento Valley. Increased cloud cover if the trough moves
inland would be a factor in this. EK
&&
.Aviation...
General VFR conditions expected over the next 24
hours. MVFR with local IFR cigs expected into I-680 until 17-18z,
with bases BKN010-012 in NE Sacramento county before eroding
around 17z. Wildfire smoke may pose slant-range visibility issues.
JClapp
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
425 AM PDT FRI AUG 21 2015
.SYNOPSIS...
DRY WEATHER WITH NEAR NORMAL TEMPERATURES THROUGH EARLY NEXT WEEK.
HAZY/SMOKY CONDITIONS WILL CONTINUE IN PORTIONS OF NORCAL.
&&
.DISCUSSION...
The Delta Breeze is still healthy early this morning which is
keeping temperatures in the upper 50s to mid 60s. And speaking of
temperatures, the short term forecast into Monday will be
reasonable & seasonable. Daytime highs will generally oscillate
within 5 degrees of normal. For areas influenced by the Delta
Breeze, daytime highs will be near to slightly below normal while
other areas will be near to slightly above normal. For today, Valley
highs will range upper 80s (near Delta) to upper 90s (near
Redding) while max temps in higher terrain will range in the 70s
(higher elevations of the Sierra) to the upper 80s/low 90s
(foothill locations). Very subtle warming occurs starting Saturday
as ridging strengthens over NorCal.
The main concern in the short term are the hazy/smoky conditions
due to fires that continue to burn, especially the many fires in
Trinity County. The HRRR model showed that smoke particulates from
the Trinity vicinty could move southward today towards Sacramento
area and then curl around as the Delta Breeze moves northward up
the valley. It`s going to be tricky to know where the worst smoke
conditions will be, but it`s a safe bet that much of interior
NorCal will at least be hazy the next several days.
JBB
&&
.EXTENDED DISCUSSION (Tuesday THROUGH Friday)
Near normal temperatures on Tuesday will be followed by
temperatures trending down through the rest of the week into the
weekend as a cool trough from the Gulf of Alaska approaches. How
quickly this system moves in is still in doubt, as the 00Z GFS and
ECMWF have essentially traded positions from model runs yesterday,
with the GFS now keeping a closed low off the coast and the ECMWF
bringing a quicker moving trough in on Friday. This would bring
the potential for some precipitation into far northern California
late Friday. While the GFS does keep the main low off the coast,
it does have a weak shortwave on Friday afternoon. Have introduced
just a slight chance of rain showers for the northern Coastal
Range for Friday afternoon. Will be watching to see if later model
runs trend closer together and need to expand this later.
Current Global Ensemble Forecast System (GEFS) ensembles and
analogs are pointing towards a cool down for late in the week.
Highs by Friday may stay in the 80s, even over the northern
Sacramento Valley. Increased cloud cover if the trough moves
inland would be a factor in this. EK
&&
.AVIATION...
General VFR conditions expected over the next 24 hours. MVFR with
local IFR cigs expected through the Delta until 17z, with SCT010
possible into the Sacramento metro area. Delta breeze wind gusts
to 30 kt through 17z. Mid level clouds over the northern
Sacramento Valley through this morning. Wildfire smoke around 5000
ft over the southern Sacramento Valley, and may extend to the
surface bringing some haze at times, local MVFR/IFR conditions for
the Coastal Range. EK
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
300 PM MDT FRI AUG 21 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM MDT FRI AUG 21 2015
TRAILING SOUTHERN END OF A SHORTWAVE MOVING THROUGH WESTERLY FLOW
ALOFT ACROSS WY AND NE CO HAS TRIGGERED THUNDERSTORMS ALONG THE SFC
TROF AXIS ACROSS EASTERN CO. MEANWHILE...REMNANT MOISTURE CAUGHT
WITHIN THE FLAT UPPER RIDGE ACROSS SOUTHWEST CO HAS TRIGGERED
THUNDERSTORMS ACROSS THE EASTERN SAN JUANS. THESE TWO AREAS WILL BE
THE FOCUS FOR CONTINUED THUNDERSTORM DEVELOPMENT THROUGH THIS
EVENING.
POTENTIAL FOR STRONGEST THUNDERSTORMS WILL BE ACROSS THE
FAR SOUTHEAST PLAINS...NAMELY KIOWA...PROWERS AND BACA COUNTIES.
DEW POINTS EAST OF THE SFC TROF AXIS WILL REMAIN IN THE
50S...YIELDING 2500+ J/KG AND DEEP LAYER SHEARS OF 30-35 KTS. THIS
WILL BE SUFFICIENT FOR ONE OR TWO SEVERE THUNDERSTORMS THROUGH THE
LATE AFTERNOON AND EVENING HOURS. HRRR PUTS THE GREATEST THREAT
ACROSS EASTERN KIOWA...PROWERS AND BACA COUNTIES. ACTIVITY SHOULD
SHIFT EASTWARD INTO KS BY 00Z. FOR THE SOUTHWEST MTS...MAIN THREAT
WILL BE LOCALLY HEAVY RAINFALL...THOUGH STORM MOTIONS TO THE EAST AT
15-20 KTS SHOULD HELP MITIGATE THE THREAT FOR FLASH FLOODING ON THE
WEST FORK BURN SCAR SOME. THIS AREA WILL STILL NEED TO BE MONITORED
CLOSELY THOUGH.
LOW TEMPERATURES TONIGHT SHOULD STAY ON THE MILD SIDE...PARTICULARLY
FOR THE SE PLAINS WHERE DOWNSLOPE WESTERLY WINDS INTO THE SFC TROF
WILL CONTINUE. MOISTURE LEVELS INCREASE OUT WEST A TAD WHICH SHOULD
KEEP MINS UP A COUPLE DEGREES OVER LAST NIGHTS VALUES AS WELL.
UPPER TROF WILL DROP OUT OF CANADA AND ACROSS THE NRN U.S. ROCKIES
ON SATURDAY. THIS WILL EVENTUALLY SEND A COLD FRONT THROUGH THE
SOUTHEAST PLAINS LATE SAT AFTN/EVENING. AHEAD OF THE FRONT ON
SATURDAY...EXPECT TEMPERATURES TO WARM QUICKLY. DEW POINTS WILL BE
THE LIMITING FACTOR...THOUGH THEY DO START TO REBOUND FROM THE 30S
INTO THE 40S ACROSS NORTHERN PORTIONS OF THE SE PLAINS LATE SAT AS
THE FRONT DROPS IN. CAPE VALUES WILL BE CONSIDERABLY
LOWER...PERHAPS UP TO 1000 J/KG BUT MOST LIKELY BELOW THIS VALUE.
SO NOT EXPECTING ANY SEVERE THUNDERSTORMS. BUT COULD SEE SOME
ISOLATED STRONGER CELLS CAPABLE OF PRODUCING LOCALLY HEAVY
RAINFALL...WHICH WOULD BE MORE OF A CONCERN FOR BURN SCARS IN EL
PASO COUNTY. FOR NOW...THREAT DOESN`T LOOK ALL THAT HIGH.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 PM MDT FRI AUG 21 2015
...COOLER SUNDAY WITH A SLOW RETURN OF THE MONSOON INTO MIDDLE OF
NEXT WEEK...
SATURDAY NIGHT-SUNDAY NIGHT...MODERATE TO STRONG WEST TO NORTHWEST
LOW ALOFT ACROSS THE REGION SATURDAY NIGHT MODERATES THROUGH THE DAY
ON SUNDAY...AS A PASSING NORTHERN TIER UPPER TROUGH CONTINUES TO
TRANSLATE SOUTH AND EAST ACROSS THE NORTHERN ROCKIES AND NORTHERN
HIGH PLAINS AND UPPER LEVEL RIDGING REBUILDS WEST ACROSS THE
SOUTHERN ROCKIES AND INTO THE DESERT SOUTHWEST. MODELS REMAIN
SIMILAR WITH BEST FORCING NORTH OF THE AREA...ALTHOUGH COULD SEE
SOME CONVECTION ALONG AN ASSOCIATED COLD FRONT MOVING ACROSS EASTERN
COLORADO LATE SATURDAY AFTERNOON THROUGH SATURDAY NIGHT. COLD FRONT
WILL ALSO BE MARKED WITH GUSTY NORTH TO NORTHEAST WINDS OF 20-30 MPH
IN ITS WAKE. OVERNIGHT LOWS TO BE TRICKY SATURDAY NIGHT...ESPECIALLY
ACROSS EASTERN COLORADO WITH WINDS SLOWLY DECOUPLING BEHIND SAID
FRONT. MODELS INDICATING A SLIGHT INCREASE IN AVAILABLE MOISTURE ON
SUNDAY...SUPPORTING ISOLATED TO SCATTERED STORMS OVER AND NEAR THE
HIGHER TERRAIN. THE BEST COVERAGE OF STORMS LOOK TO BE ACROSS THE
SOUTHERN MTS WITH THE EASTERN PLAINS EXPECTED TO BE CAPPED. HIGHS ON
SUNDAY TO BE 5-15F COOLER THAN SATURDAY...MOST NOTABLE OVER THE
EASTERN PLAINS WITH BREEZY SOUTH TO SOUTHEAST UPSLOPE FLOW
DEVELOPING IN THE AFTERNOON. WARMING ALOFT NOTED ACROSS THE AREA
SUNDAY NIGHT...THOUGH COULD SEE SOME COOLER OVERNIGHT LOWS SUNDAY
NIGHT WITH GOOD RADIATIONAL COOLING ACROSS THE LOWER ELEVATIONS.
MONDAY-FRIDAY...A RETURN TO A MORE MONSOONAL PATTERN LOOKS TO BE IN
THE OFFING AS THE UPPER RIDGE ACROSS THE DESERT SOUTHWEST AND INTO
THE GREAT BASIN SLOWLY BUILDS EAST ACROSS THE CENTRAL AND NORTHERN
ROCKIES. SOME DIFFERENCES NOTED IN LONGER RANGE MODELS WITH THE
LATEST GFS BRINGING A DISTURBANCE ACROSS THE STATE ON WEDNESDAY
SUPPORTING MORE WIDESPREAD CONVECTION ACROSS THE AREA...WHERE AS THE
ECMWF IS SLOWER AND FURTHER NORTH WITH THE DISTURBANCE. AT ANY
RATE...SHOULD SEE A SLOW INCREASE IN SUBTROPICAL MOISTURE THROUGH
THE PERIOD...WITH DAILY CHANCES OF SHOWERS AND THUNDERSTORMS OVER
AND NEAR THE HIGHER TERRAIN SLOWLY INCREASING AND SPREADING EAST
THROUGH THE PERIOD. AT OR ABOVE SEASONAL TEMPERATURES EXPECTED TO
RETURN TO THE AREA THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 300 PM MDT FRI AUG 21 2015
CONDITIONS SHOULD REMAIN VFR AT THE TERMINALS...WITH SMOKE
REDUCING THE VISIBILITIES AT TIMES. FOR NOW...DO NOT THINK SMOKE
WILL BECOME THICK ENOUGH TO REDUCE VISIBILITIES TO UNDER 6 MILES.
ISOLATED THUNDERSTORMS THIS EVENING ARE EXPECTED TO BYPASS THE
TERMINALS...THOUGH KALS COULD SEE A WINDOW OF GUSTY WEST WINDS IF
THUNDERSTORM OUTFLOWS HOLD TOGETHER AS THEY PUSH EASTWARD OFF THE
SOUTHWEST MTS. THUNDERSTORMS WILL DIMINISH THIS EVENING. A FRONT
WILL DROP SOUTH OF THE PALMER DIVIDE SAT AFTERNOON...AND WILL
BRING A SLIGHTLY BETTER CHANCE FOR THUNDERSTORMS AT THE KCOS TAF
SITE DURING THE AFTERNOON. LIGHTNING...BRIEF RAINFALL AND GUSTY
OUTFLOW WINDS WILL BE THE PRIMARY STORM THREATS. THIS FRONT WILL
SHIFT SOUTHWARD INTO THE KPUB AREA AROUND 00Z SUN. NORTHERLY WIND
GUSTS BEHIND THE FRONT COULD GUST UP TO 30-35 KTS AT BOTH KCOS AND
KPUB. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
303 PM EDT FRI AUG 21 2015
.DISCUSSION...
TONIGHT AND SATURDAY...EAST AND WEST COAST BREEZE BOUNDARIES
COMING TOGETHER OVER THE CENTER OF THE STATE WILL BRING THE BEST
CHANCE FOR STORM DEVELOPMENT LATE THIS AFTERNOON AND INTO THE
EARLY EVENING. LTST HRRR GUID SHOWS A BREEZE COLLISION WEST OF
METRO ORLANDO AFTER 5 PM. A FEW STRONG STORMS WILL BE POSSIBLE
WITH WIND GUSTS OF 40 TO 50 MPH AND FREQUENT LIGHTNING...ESP FROM
THE THEME PARKS TO LAKE COUNTY AND LAKE GEORGE. PCPN TIED TO SFC
HEATING AND BOUNDARY COLLISIONS SHOULD COME TO AN END OVER LAND
AREAS BY 1030 PM.
SAT...STACKED HIGH OVER THE STATE WL MAINTAIN CONTROL WITH MORE
STABLE CONDS OVERALL. NE WINDS WL WOKR SWD FROM THE MID ATLC
SEABOARD...PROVIDING ADTL LWR LEVEL STABILITY IN THE FORM OF A
MARINE INFLUENCE TO THE COAST AND ESP NORTHERN AREAS. PRECIP CHCS
HAVE BEEN TAPERED BACK TO ISOLD ALONG THE CST AND 30 TO 40
PERCENT INLAND. CONVERGENCE IN THE AFTN BEST SUITABLE FOR PCPN
DEVELOPMENT SHOULD LARGELY OCCUR OVER THE WESTERN SIDE OF THE
PENINSULA.
SUN...(MODIFIED PREV DISC)...MID-LEVEL HIGH PRESSURE OVER THE
GOMEX GRADUALLY WEAKENS AS SHORTWAVE IMPULSES TRAVERSE THE N/NE
PERIPHERY OF THIS ANTI-CYCLONE. THIS WILL ALLOW NORTHERLY WINDS
TO BACK TO NORTHWESTERLY. 500 MB TEMPERATURES WILL REMAIN FAIRLY
WARM AT -5C/- 6C. AT THE SURFACE HIGH PRESSURE ACROSS THE EASTERN
CONUS WILL WEAKEN AND DRIFT TOWARD THE EASTERN SEABOARD/WESTERN
ATLC WITH THE APPROACH OF A COLD FRONT. THE SURFACE PRESSURE
GRADIENT WILL REMAIN WEAK THROUGH THIS PERIOD WITH LIGHT
NORTHEASTERLY FLOW. THE EAST COAST SEA BREEZE WILL DEVELOP EACH
DAY AND PUSH INLAND. GREATEST STORM CHANCES WILL FAVOR THE
INTERIOR EACH AFTERNOON WITH STEERING FLOW FROM THE N/NNE.
MON-THU...TROUGHING IN THE MID-LEVELS WILL GRADUALLY DEVELOP ACROSS
THE EASTERN CONUS THROUGH THIS TIME AS NWRLY FLOW ALOFT BECOMES
SWRLY ACROSS THE AREA. DEEP LAYER MOISTURE WILL BE LOWER THAN
PREVIOUS DAYS. A WEAK SURFACE BOUNDARY WILL BECOME NEAR STATIONARY
ACROSS THE DEEP SOUTH WITH WEAK HIGH PRESSURE CONTINUING OVER ECFL.
OUR LIGHT ONSHORE FLOW WILL BECOME LIGHT S/SWRLY WED-THU THOUGH THE
EAST COAST SEA BREEZE WILL STILL DEVELOP EACH AFTERNOON AND PUSH
INLAND. NORTHERLY STORM STEERING FLOW WILL CONTINUE MON-TUE WITH
LOWER CONFIDENCE WED-THU IN STORM MOTION...THOUGH IT APPEARS TO BE
LIGHT/ERRATIC FOR NOW. LOWER THAN NORMAL PRECIPITATION CHANCES LIKELY
MON-TUE WITH AN UPTICK AGAIN MOVING INTO/PAST MID-WEEK TOWARDS CLIMO
NUMBERS.
&&
.AVIATION...VFR CONDS ALL COASTAL SITES WITH BRIEF MVFR CONDS
PSBL INTERIOR SITES THIS AFTN THROUGH 22/02Z IN ISOLD RELATIVELY
BRIEF TSRA/SHRA...OTHERWISE VFR CONDS INTERIOR AS WELL THROUGH
22/16Z.
&&
.MARINE...
TONIGHT AND SATURDAY...LIGHT WINDS WITH THE DIURNAL ONSHORE
BREEZE IN THE AFTERNOON WL MAINTAIN SIG WVS 2 FT OR LESS DURING
THE PERIOD. ONSHORE WINDS WILL INCREASE FROM N TO S ON SAT AS A
NE PRIMARY WIND ENTERS THE NE AND CENTRAL FL WATERS BY LATE
SATURDAY AFTN.
NEXT WEEK...WEAK PRESSURE GRADIENT OVER THE AREA WITH A LIGHT
N/NE WIND FLOW BELOW 10 KTS. GRADIENT IS SO WEAK THAT WINDS MAY BE
MORE VARIABLE IN DIRECTION AT TIMES. THE ECSB WILL DEVELOP EACH
AFTERNOON PUSHING INLAND WITH A SLIGHT BUMP UP IN SPEEDS NEAR THE
IMMEDIATE COAST. ONLY AN ISOLD THREAT FOR SHRA/TSRA. SEA HEIGHTS
AOB 3 FT.
MON-TUE...THE WEAK PRESSURE GRADIENT AND LIGHT WIND FIELDS CONTINUE
INTO EARLY WEEK AS A WEAK FRONTAL BOUNDARY SETTLES ACROSS THE DEEP
SOUTH/SOUTHEAST U.S. DAILY SEA BREEZE FORMATION AND PUSH INLAND
DURING THE AFTERNOON WILL ALSO REMAIN COMMON. SHOWER/STORM CHANCES
REMAIN ISOLD. SEAS AOB 3 FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 76 93 76 90 / 20 20 20 20
MCO 76 94 76 93 / 30 40 20 20
MLB 76 92 77 90 / 20 20 20 20
VRB 73 91 74 89 / 20 20 20 20
LEE 77 95 77 93 / 30 40 20 30
SFB 77 95 77 93 / 30 40 20 20
ORL 77 95 77 94 / 30 40 20 20
FPR 74 92 74 89 / 20 20 20 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
PUBLIC/MARINE...PENDERGRAST
IMPACT WEATHER/AVIATION...WIMMER
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
339 AM EDT FRI AUG 21 2015
.DISCUSSION...
TODAY...GPS PRECIPITABLE WATER VALUES WERE A LITTLE ABOVE 2
INCHES EARLY THIS MORNING. RECENT CLOUD TRENDS SHOW DEBRIS CLOUDS
THINNING OUT SO THERE WILL BE AMPLE MORNING HEATING. HOWEVER...THE
LATEST RAP ANALYSIS SHOWS 700MB TEMPS 10-11 CELSIUS...WHICH
USUALLY INDICATES DEEP CONVECTIVE DEVELOPMENT WILL BE DELAYED
SOME.
THE AXIS OF A WEAKENING SURFACE RIDGE OVER NORTH BAHAMAS WILL
PROVIDE LIGHT WEST/SOUTHWEST WINDS THIS MORNING...DELAYING THE
ONSET OF EAST COAST SEA BREEZE UNTIL NOON TO EARLY AFTERNOON. THIS
WILL ALLOW SOME HEAT INDEX READINGS TO REACH 100-105 BEFORE
CONVECTION INITIATES. ADDITIONALLY...THIS HOT/SULTRY AIR MASS WILL
ALLOW FOR A CHANCE OF STORMS ALONG THE COAST BEFORE THE SEA BREEZE
PUSHES WELL INLAND. THE STRONGEST BOUNDARY INTERACTIONS WILL OCCUR
OVER THE INTERIOR DURING THE LATE AFTERNOON TO EARLY EVENING.
MOS POPS CAME IN 30 PERCENT RIGHT ALONG THE COAST AND ONLY 30-50
PERCENT OVER THE INTERIOR. HAVE FOLLOWED THIS DOWNWARD TREND BUT
KEPT THE INTERIOR POPS AT 50 PERCENT.
FREQUENT LIGHTNING STRIKES IN STRONGER STORMS ARE LIKELY MAINLY
OVER THE INTERIOR. WEAK STEERING FLOW INDICATES A CONTINUED
POTENTIAL FOR QUICK 2-3 INCH RAIN AMOUNTS. GFS FORECAST SOUNDINGS
SHOW A LITTLE MID LEVEL DRYING DURING THE DAY SO A THREAT FOR
DOWNBURST WINDS 40-50 KNOTS ARE POSSIBLE TOO.
SAT-SUN...MID-LEVEL HIGH PRESSURE OVER THE GOMEX GRADUALLY
WEAKENS LATE SUN/SUN NIGHT AS SHORTWAVE IMPULSES TRAVERSE THE N/NE
PERIPHERY OF THIS ANTI-CYCLONE. THIS WILL ALLOW NORTHERLY WINDS TO
BACK TO NORTHWESTERLY. 500 MB TEMPERATURES WILL REMAIN FAIRLY WARM
AT -5C/- 6C. AT THE SURFACE HIGH PRESSURE ACROSS THE EASTERN CONUS
WILL WEAKEN AND DRIFT TOWARD THE EASTERN SEABOARD/WESTERN ATLC
WITH THE APPROACH OF A COLD FRONT. THE SURFACE PRESSURE GRADIENT
WILL REMAIN WEAK THROUGH THIS PERIOD WITH LIGHT NORTHEASTERLY
FLOW. THE EAST COAST SEA BREEZE WILL DEVELOP EACH DAY AND PUSH
INLAND. GREATEST STORM CHANCES WILL FAVOR THE INTERIOR EACH
AFTERNOON WITH STEERING FLOW FROM THE N/NNE.
MON-THU...TROUGHING IN THE MID-LEVELS WILL GRADUALLY DEVELOP ACROSS
THE EASTERN CONUS THROUGH THIS TIME AS NWRLY FLOW ALOFT BECOMES
SWRLY ACROSS THE AREA. DEEP LAYER MOISTURE WILL BE LOWER THAN
PREVIOUS DAYS. A WEAK SURFACE BOUNDARY WILL BECOME NEAR STATIONARY
ACROSS THE DEEP SOUTH WITH WEAK HIGH PRESSURE CONTINUING OVER ECFL.
OUR LIGHT ONSHORE FLOW WILL BECOME LIGHT S/SWRLY WED-THU THOUGH THE
EAST COAST SEA BREEZE WILL STILL DEVELOP EACH AFTERNOON AND PUSH
INLAND. NORTHERLY STORM STEERING FLOW WILL CONTINUE MON-TUE WITH
LOWER CONFIDENCE WED-THU IN STORM MOTION...THOUGH IT APPEARS TO BE
LIGHT/ERRATIC FOR NOW. LOWER THAN NORMAL PRECIPITATION CHANCES LIKELY
MON-TUE WITH AN UPTICK AGAIN MOVING INTO/PAST MID-WEEK TOWARDS CLIMO
NUMBERS.
&&
.AVIATION...MAINLY VFR UNTIL STORMS START FIRING THIS AFTERNOON.
ALL OF THE COASTAL SITES WILL HAVE A CHANCE OF STORMS FROM ABOUT
16-20Z. OUTFLOW BOUNDARY MERGERS WILL PROPAGATE STORMS TO THE
INTERIOR TERMINALS WITH THE GREATEST CHANCE ABOUT 19-23Z. CANNOT
PIN DOWN WHICH TERMINALS WILL BE AFFECTED BY STRONG STORMS...BUT
INTERIOR SITES WILL HAVE A SLIGHT CHANCE FOR TORRENTIAL DOWNPOURS...
FREQUENT LIGHTNING STRIKES AND GUSTY WINDS ABOVE 35 KNOTS.
&&
.MARINE...
TODAY-TONIGHT...WEAK PRESSURE GRADIENT TYPICAL OF THE AUGUST
DOLDRUMS WILL CONTINUE SO THERE ARE NO WIND/SEA CONCERNS. WEAK
STEERING TODAY SHOULD CONFINE STORM POTENTIAL TO THE MAINLAND BUT
A FEW COULD AFFECT THE INTRACOASTAL...ESPECIALLY FROM THE CAPE
NORTHWARD DURING THE EARLY TO MID AFTERNOON.
WEEKEND...WEAK PRESSURE GRADIENT OVER THE AREA WITH A LIGHT N/NE
WIND FLOW BELOW 10 KTS. GRADIENT IS SO WEAK THAT WINDS MAY BE MORE
VARIABLE IN DIRECTION AT TIMES. THE ECSB WILL DEVELOP EACH AFTERNOON
PUSHING INLAND WITH A SLIGHT BUMP UP IN SPEEDS NEAR THE IMMEDIATE
COAST. ONLY AN ISOLD THREAT FOR SHRA/TSRA. SEA HEIGHTS AOB 3 FT.
MON-TUE...THE WEAK PRESSURE GRADIENT AND LIGHT WIND FIELDS CONTINUE
INTO EARLY WEEK AS A WEAK FRONTAL BOUNDARY SETTLES ACROSS THE DEEP
SOUTH/SOUTHEAST U.S. DAILY SEA BREEZE FORMATION AND PUSH INLAND
DURING THE AFTERNOON WILL ALSO REMAIN COMMON. SHOWER/STORM CHANCES
REMAIN ISOLD. SEAS AOB 3 FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 92 76 90 75 / 40 20 30 20
MCO 94 76 93 76 / 50 20 50 20
MLB 92 77 90 77 / 40 20 30 20
VRB 92 74 89 75 / 40 20 30 20
LEE 94 77 94 77 / 50 20 50 20
SFB 94 77 93 77 / 50 20 40 20
ORL 95 78 94 77 / 50 20 50 20
FPR 92 73 89 74 / 40 20 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...LASCODY
LONG TERM....SEDLOCK
AREA FORECAST DISCUSSION
NWS MIAMI FL
138 AM EDT FRI AUG 21 2015
.AVIATION...
VFR WILL PREVAIL OVERNIGHT. A WEAK LAND BREEZE DEVELOPING COULD
ALLOW FOR SCATTERED THUNDERSTORMS TO DEVELOP ACROSS THE EAST
COAST BY MID MORNING FRI THEN OVER THE INTERIOR WITH MOVEMENT TO
THE GULF COAST THROUGH THE DAY. ADDED VCTS FOR ALL TERMINALS GIVEN
THIS REGIME EXPECTED. ANY DIRECT TSRA IMPACTS WOULD BE BRIEF, BUT
BRIEF IFR WILL BE POSSIBLE IN HEAVY RAIN. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 758 PM EDT THU AUG 20 2015/
AVIATION...
SLIGHTLY WEAKER WIND FLOW WILL BE THE ONLY CHANGE TO THE CURRENT
REGIME ON FRIDAY. IN ADDITION, A WEAKER OR NO SUBSIDENCE CAP MAY
LEAD TO MORE NUMEROUS STORMS, SOME OF WHICH MAY BE CLOSER TO THE
EAST COAST TAF SITES. HOWEVER, WITH FOCUS STILL OVER THE INTERIOR,
AND NOT A GREAT DEAL OF CONFIDENCE, WILL NOT ADD VCTS AT THIS
TIME TO THE EAST COAST. A BRIEF MVFR CIG CAN OCCUR ONCE AGAIN NEAR
DAWN UNDER EAST FLOW.
PREV DISCUSSION... /ISSUED 747 PM EDT THU AUG 20 2015/
UPDATE...
MAKING SOME MINOR ADJUSTMENTS TO THE EVENING UPDATES BASED ON
LATEST TRENDS. EARLY EVENING ACTIVITY SHOULD DIMINISH BY 02Z WITH THE
GRADIENT FLOW WEAKENING CONSIDERABLY SO THE CHANCES FOR ATLANTIC
DEVELOPMENT LATER TONIGHT MOVING ONSHORE SEEM RATHER REMOTE AT
THIS TIME. NEITHER THE HRRR NOR THE LOCALLY RUN WRF SHOW THIS
OCCURRING SO AM REMOVING MENTION OF THUNDER ALL AREAS WITH THE
EXCEPTION OF THE THE OFFSHORE WATERS FOR LATER TONIGHT.
KOB
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 92 78 92 / 20 40 30 40
FORT LAUDERDALE 79 92 79 91 / 20 50 40 50
MIAMI 79 94 78 92 / 30 50 40 50
NAPLES 78 91 77 93 / 30 50 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
751 PM EDT SAT AUG 22 2015
.SYNOPSIS...
WEAK HIGH PRESSURE WILL PREVAIL INTO SUNDAY. ANOTHER COLD FRONT
IS EXPECTED TO APPROACH FROM THE NORTHWEST EARLY NEXT WEEK...THEN
LIKELY STALL OVER OR NEAR THE REGION THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A SHORTWAVE TROUGH CURRENTLY OVER THE CENTRAL SAVANNAH RIVER AREA
WILL CONTINUE TO MOVE SOUTHEAST TOWARD SAVANNAH-BEAUFORT BY EARLY
THIS EVENING AND OFF THE COAST. MEANWHILE THE SEA BREEZE HAS
PUSHED PART-WAY INTO SOUTHEAST GA AND FARTHER INTO SOUTHEAST SC.
THE SEA BREEZE IN SOUTHERN SC HAS BEEN ENHANCED BY EARLIER
CONVECTIVE OUTFLOWS. CONVECTION ASSOCIATED WITH THE SHORTWAVE WILL
DRIVE SOUTHEAST THROUGH LATE AFTERNOON...EVENTUALLY INTERACTING
WITH THE SEA BREEZE AND OTHER BOUNDARIES. THE HRRR HAS BEEN DOING
QUITE WELL THUS FAR TODAY AND THE GOING FORECAST HAS NOT CHANGED
MUCH FROM EARLIER PROGS. THE INCOMING CONVECTION WILL DROP
SOUTHEAST AND THEN SOUTH-SOUTHEAST DOWN THE SEA BREEZE THROUGH 7
OR 8 PM. THE BEST COVERAGE WILL BE SOUTH OF WALTERBORO DOWN TOWARD
BEAUFORT AND SAVANNAH. MODERATE INSTABILITY BUT WEAK MID-LEVEL
LAPSE RATES IN PLACE AT THIS TIME. ISOLATED DAMAGING WIND GUSTS
POSSIBLE WITH MORE ORGANIZED MULTI-CELL STORMS. ALSO LOCALIZED
HEAVY RAINFALL GIVEN PWATS ABOVE 2.1" AND SOME MERGING CELLS.
ACTIVITY SHOULD TAPER OFF EARLY TO MID EVENING AS THE SHORTWAVE
MOVES OFFSHORE AND THE BOUNDARY LAYER STABILIZES. WEAK NORTHEAST
FLOW ACROSS INTERIOR AREAS...DRIER AIR FILTERING IN ABOVE THE
SURFACE AND WET SOILS COULD SUPPORT SOME FOG AWAY FROM THE COAST.
WE MAINTAINED PATCHY FOG IN THE GRIDDED FORECAST.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
HIGH PRESSURE EARLY SUNDAY WILL SHIFT OFFSHORE LATER IN THE DAY AND
REMAIN OVER THE ATLANTIC THROUGH TUESDAY AS A COLD FRONT APPROACHES
FROM THE WEST...EVENTUALLY STALLING INLAND. ALOFT...GENERAL
TROUGHINESS WILL PERSIST AND WITH PLENTIFUL MOISTURE MUCH OF THE
TIME RAIN CHANCES LOOK TO BE AT LEAST NORMAL FOR THIS TIME OF YEAR
/ABOUT 30 PERCENT/.
SUNDAY...HIGH PRESSURE TO START THE DAY WILL SHIFT OFFSHORE AS A
SHORTWAVE TROUGH APPROACHES FROM THE WEST. THE DEEPEST MOISTURE
LOOKS TO BE GENERALLY SOUTH AND WEST OF CHARLESTON WHICH WILL BE
CLOSER TO THE INLAND TROUGH AND THIS IS WHERE WE HAVE THE HIGHEST
/40 PERCENT/ RAIN CHANCES. HIGH TEMPS MOSTLY IN THE LOWER 90S WITH
HEAT INDICES MAINLY 95-100 OVER SOUTH CAROLINA AND CLOSER TO 105
NEAR THE ALTAMAHA RIVER. RAIN CHANCES WILL WIND DOWN SUNDAY NIGHT
AND SHIFT OFFSHORE ALONG WITH THE SHORTWAVE. LOWS A BIT ABOVE NORMAL
IN THE LOWER 70S INLAND AND MID TO UPPER 70S NEAR THE COAST.
MONDAY...THE UPPER TROUGH WILL BE OFFSHORE AND WITH SLIGHTLY LOWER
PWATS RAIN CHANCES SHOULD BE A BIT LOWER AS WELL. HOWEVER...THE SEA
BREEZE AND INLAND TROUGH SHOULD LEAD TO SOME SHOWERS AND
THUNDERSTORMS...LIKELY NEAR THE COAST IN THE MORNING...THEN SHIFTING
INLAND IN THE AFTERNOON. HIGHS ABOVE NORMAL IN THE LOWER TO MID 90S
WITH HEAT INDICES NEAR 100 DEGREES MOST INLAND AREAS AND CLOSER TO
105 DEGREES NEAR THE ALTAMAHA RIVER. RAIN WILL DIMINISH IN THE EARLY
EVENING WITH MOSTLY DRY CONDITIONS OVERNIGHT ALTHOUGH THE WEAK COLD
FRONT OVER CENTRAL SC/GA WILL BE PUSHING TOWARD THE COAST LATE. LOWS
WILL BE WARM IN THE LOWER 70S INLAND AND MID TO UPPER 70S CLOSER TO
THE COAST.
TUESDAY...STRONGER UPPER TROUGHING RE-DEVELOPS ACROSS THE AREA IN
RESPONSE TO A DEEP UPPER LOW OVER THE GREAT LAKES REGION. A WEAK
COLD FRONT OVER INLAND AREAS SHOULD STALL DUE TO DIURNAL
HEATING...PROVIDING A FOCUS FOR SCATTERED SHOWERS AND THUNDERSTORMS
MAINLY IN THE AFTERNOON. MORE CLOUDS AND HIGHER RAIN COVERAGE SHOULD
LIMIT HIGHS A BIT...AROUND 90 NORTH WITH MID 90S OVER SOUTHEAST
GEORGIA. HEAT INDICES WILL AGAIN BE NEAR TO SLIGHTLY ABOVE 100
DEGREES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
GLOBAL MODELS ALL SHOW THAT AT LEAST A BROAD UPPER TROUGH WILL
REMAIN OVER THE EASTERN U.S. DOWN INTO THE SOUTHEAST THROUGH MUCH OF
THE PERIOD. THE GFS SEEMS TO BE THE STRONGEST/MOST AGGRESSIVE WITH
THE UPPER TROUGH. AT THE SURFACE...EVEN WITH THE STRONGER GFS
SOLUTION FOR THE UPPER TROUGH...IT STILL APPEARS THAT A WEAK COLD
FRONT STALLS NEAR OR JUST WEST OF THE AREA THROUGH THE PERIOD.
HOWEVER...THERE IS STILL SOME UNCERTAINTY WITH THIS SOLUTION...AND
THE GUIDANCE INDICATES THAT SOME DRIER LOW LEVEL AIR MAY
WORK INTO AT LEAST THE WESTERN ZONES MID TO LATE WEEK. SURFACE/LOW
LEVEL WINDS FIELDS ARE EXPECTED TO BE LIGHT THROUGH THE
PERIOD...ALLOWING AFTERNOON SEA BREEZES TO DEVELOP EACH
DAY...HELPING TO SPARK CONVECTION. HAVE KEPT LOW END CHANCE POPS
MUCH OF THE PERIOD FOR MAINLY AFTERNOON CONVECTION. EVEN WITH THE
UPPER TROUGH...GUIDANCE STILL SHOWING TEMPERATURES ABOVE NORMAL
THROUGH THE PERIOD...WITH HIGHS AROUND 90 TO THE LOWER 90S AND LOWS
IN THE LOWER 70S.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR WILL PREVAIL THROUGH MOST OF THE VALID 0ZZ TAF CYCLE.
HOWEVER...THERE IS THE POTENTIAL FOR SOME FOG LATE TONIGHT
THROUGH DAYBREAK SUNDAY. WE MAINTAINED 6SM AT BOTH SITES SINCE WE
THINK THE BEST FOG DEVELOPMENT WILL BE FARTHER INLAND.
HOWEVER...SINCE BOTH TERMINALS WILL HAVE WET SOIL...FOG MAY VERY
WELL SPREAD FARTHER SOUTHEAST AND DROP VSBYS AT ONE OR BOTH
TERMINALS INTO MVFR OR LOWER. SCATTERED CONVECTION COULD AGAIN
IMPACT THE TERMINALS SUNDAY AFTERNOON/EVENING. BUT PROBABILITIES
ARE TOO SMALL TO INCLUDE AT THIS TIME.
EXTENDED AVIATION OUTLOOK...MOSTLY VFR. MAINLY AFTERNOON SCATTERED
SHOWERS/THUNDERSTORMS EXPECTED THROUGH THE PERIOD POSSIBLY LEADING
TO BRIEF PERIODS OF FLIGHT RESTRICTIONS AT BOTH TERMINALS. LOWEST
CHANCES PROBABLY ON MONDAY.
&&
.MARINE...
WITH WEAK COLD FRONT DRAPED ACROSS THE AREA...WINDS WILL BE
RELATIVELY LIGHT THROUGH THE OVERNIGHT HOURS. THE ONLY EXCEPTION
WILL BE ALONG THE COAST LINE WHERE A 10-12 KT SEA BREEZE WILL
PERSIST UNTIL EARLY EVENING.
SUNDAY THROUGH THURSDAY...NO SIGNIFICANT CONCERNS THROUGH THE PERIOD
AS HIGH PRESSURE GIVES WAY TO AN APPROACHING WEAK COLD FRONT WHICH
WILL STALL INLAND. WINDS WILL PICK UP FROM THE SOUTH TOWARD MID WEEK
BUT SHOULD MOSTLY BE 15 KT OR LESS WITH SEAS BUILDING UP TO 4 FT
BEYOND 20 NM.
WATERSPOUTS...CONDITIONS APPEAR TO BE FAVORABLE FOR AN ENHANCED RISK
OF WATERSPOUTS EACH MORNING THROUGH MONDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JRL
SHORT TERM...RJB
LONG TERM...RFM
AVIATION...
MARINE...JRL/RJB
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
310 PM EDT FRI AUG 21 2015
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
FRONTAL BOUNDARY CONTINUES ACROSS CENTRAL GA THIS AFTERNOON. THE
BOUNDARY WILL CONTINUE TO OOZE SOUTHWARD THROUGH THE EVENING. IN THE
MID LEVELS...WV AND RAP ANALYSIS SHOWS A FAIRLY DECENT SHORTWAVE
HELPING TO ENHANCE SHOWERS AND THUNDERSTORM DEVELOPMENT IN
CENTRAL/EASTERN AL. THE SHORTWAVE WILL CONTINUE EASTWARD...SPREADING
CONVECTION INTO NORTH CENTRAL GA AND WILL ALSO HELP PUSH THE OLD
FRONT A LITTLE FURTHER SOUTH.
SURFACE INSTABILITY IS GREATEST ALONG AND SOUTH OF THE FRONT BUT MID
LEVEL LAPSE RATES REMAIN WEAK. WITH HIGH PWATS...MAIN HAZARDS FROM
STORMS WILL BE LOCALLY HEAVY RAINFALL PLUS FREQUENT LIGHTNING. A FEW
STRONG STORMS ARE POSSIBLE WITH GUSTY WINDS.
THE FRONT SHOULD MOVE TO OVER THE SOUTHERN PORTION OF THE CWFA
TONIGHT. WITH THE LOSS OF HEATING...CONVECTIVE COVERAGE SHOULD
MOSTLY DIMINISH.
MODELS ARE PROGGING ANOTHER GOOD SHORTWAVE TO MOVE EAST IN THE FLOW
TOMORROW. THE DISTURBANCE WILL INTERACT WITH THE OLD BOUNDARY AND
PRODUCE SCATTERED/ISOLD SHRA/TSRA AGAIN TOMORROW AFTERNOON.
NLISTEMAA
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MAINLY ONLY TWEAKS TO THE LONG TERM BASED ON THE LASTEST GUIDANCE.
BDL
PREVIOUS DISCUSSION...
THE EXTENDED FORECAST START OFF WITH WEAKENING BOUNDARY ACROSS
CENTRAL GA SUNDAY MOVING SOUTH. THE NEXT FRONTAL SYSTEM BEGINS TO
MOVE INTO N GA MONDAY MORNING BUT THERE IS NOT MUCH MOISTURE ASSOCIATED
WITH IT. THIS BOUNDARY WILL ACT AS A CATALYST FOR STORMS TO
DEVELOP ACROSS THE AREA MONDAY AND TUESDAY BUT IT WILL ALSO USHER
IN A MUCH DRIER AIRMASS TUESDAY NIGHT. THIS DRIER AIR IS EXPECTED
TO STAY ACROSS THE REGION THROUGH THURSDAY WHICH WILL KEEP
SHRA/TSRA ACTIVITY TO A MINIMUM. ALL IN ALL IT LOOKS LIKE WE MAY
BE IN THE BEGINNING STAGES OF TRANSITIONING TO A MORE FALL LIKE
PATTERN...WITH FRONTS MOVING THROUGH THE STATE GIVING THE CWA
MOSTLY CLEAR SKIES FOR A FEW DAYS AND NOT STALLING ACROSS CENTRAL
OR SOUTH GA. TEMPS REMAIN IN THE MID 80S TO MID 90S THROUGH THE
EXTENDED.
01
&&
.AVIATION...
18Z UPDATE...
CONVECTION HAS BEGUN DEVELOPING ACROSS THE AREA WITH KMCN AND KCSG
ALONG MAIN LINE. SO FAR STORMS HAVE REMAINED SHOWERS BUT WE ARE
EXPECTING THUNDERSTORMS ACROSS THE TAF SITES MAINLY 19-24Z. WINDS
WILL BE NORTHWEST TO WEST AT 5-10KTS INITIALLY...DIMINISHING AFTER
00Z WITH THE LOOS OF HEATING. PATCHY FOG WILL DEVELOP IN THE USUAL
SUSPECTS AND RAIN SOAKED AREAS BY DAYBREAK WITH MVFR VISIBILITIES.
EXPECT CIGS IN MVFR/VFR RANGE THROUGH THE PERIOD.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON CIGS/TIMING OF TS
MEDIUM TO HIGH ON ALL OTHER ELEMENTS.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 89 72 90 / 30 30 20 40
ATLANTA 73 89 73 89 / 20 30 20 40
BLAIRSVILLE 64 83 66 84 / 30 30 20 50
CARTERSVILLE 69 90 69 90 / 20 30 20 40
COLUMBUS 75 92 75 92 / 20 30 20 30
GAINESVILLE 71 86 71 87 / 30 30 20 50
MACON 73 93 74 92 / 30 30 20 40
ROME 69 89 70 90 / 20 20 20 30
PEACHTREE CITY 71 91 72 90 / 20 30 20 40
VIDALIA 75 93 74 92 / 30 30 20 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NLISTEMAA
LONG TERM....BDL
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
201 PM EDT FRI AUG 21 2015
.PREV DISCUSSION... /ISSUED 949 AM EDT FRI AUG 21 2015/
UPDATE...
OLD FRONTAL BOUNDARY CURRENTLY DRAPED ACROSS CENTRAL GA THIS
MORNING. IN THE MID LEVELS...A SHEAR AXIS IS SITUATED ALMOST
DIRECTED ON TOP OF THE BOUNDARY.
WV AND 500MB RAP ANALYSIS SHOWS A WEAK WAVE SHORTWAVE ASSOCIATED
WITH THE SHOWERS ACROSS EASTERN GA THIS MORNING. THERE ARE TWO MORE
SHORTWAVES ANALYZED IN THE FLOW...ONE ACROSS CENTRAL AL AND ANOTHER
ACROSS THE ARKLAMISS. THE WAVE ACROSS CENTRAL AL SHOULD HELP SCT
CONVECTION DEVELOP THIS AFTERNOON DURING PEAK HEATING ACROSS MUCH OF
THE CWFA.
HAVE UPDATED THE POPS ACCORDING TO THE LATEST RADAR TRENDS. HAVE
ALSO TWEAKED THE AFTERNOON POPS A BIT TO COME A LITTLE MORE INTO
LINE WITH THE HRRR...WHICH HAS A PRETTY GOOD HANDLE ON THE SHRA THAT
ARE ONGOING.
LOCALLY HEAVY RAINFALL AND FREQUENT LIGHTNING STRIKES ARE THE MAIN
HAZARDS ASSOCIATED WITH ANY THUNDERSTORMS THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 414 AM EDT FRI AUG 21 2015/
SHORT TERM /TODAY THROUGH SATURDAY/...
NAM/GFS/ECMWF IN VERY GOOD AGREEMENT THROUGH THE SHORT TERM. SURFACE
TROUGH HAS STALLED ACROSS NORTH GEORGIA KEEPING MOST OF THE CWA IN
THE WARM AND MOIST SECTOR. THIS TROUGH WILL NOT MOVE MUCH BUT SHOULD
BE A FOCUS FOR CONVECTION THIS AFTERNOON AS A WEAK WAVE MOVES ALONG
THE BOUNDARY. AFTER THIS WAVE MOVES TO OUR EAST...THE SURFACE TROUGH
WILL SHIFT SOUTH. CAPES REMAIN IN THE 1500-2000 RANGE ALONG WITH
PWATS RANGING FROM 1.8 TO 2.1 INCHES. WILL KEEP HIGH CHANCE POPS
ACROSS NORTH AND PARTS OF CENTRAL GA WHERE THE DEEPEST MOISTURE WILL
BE WITH CHANCE POPS ELSEWHERE. CONVECTION WILL DIMINISH QUICKLY THIS
EVENING. ON SATURDAY EXPECT CONVECTION AGAIN ALTHOUGH WITH SLIGHTLY
DRIER AIR OVER THE REGION WILL LIMIT POPS TO SLIGHT CHANCE TO CHANCE
AND MAINLY DURING THE AFTERNOON. GUIDANCE TEMPS HAVE BEEN RUNNING 1
TO 2 DEGREES TOO LOW OVER THE PAST 10 DAYS AND HAVE THEREFORE RAISED
MAX TEMPS BOTH DAYS BY A DEGREE OR TWO.
17
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE EXTENDED FORECAST START OFF WITH WEAKENING BOUNDARY ACROSS
CENTRAL GA SUNDAY MOVING SOUTH. THE NEXT FRONTAL SYSTEM BEGINS TO
MOVE INTO N GA MONDAY MORNING BUT THERE IS NOT MUCH MOISTURE ASSOCIATED
WITH IT. THIS BOUNDARY WILL ACT AS A CATALYST FOR STORMS TO
DEVELOP ACROSS THE AREA MONDAY AND TUESDAY BUT IT WILL ALSO USHER
IN A MUCH DRIER AIRMASS TUESDAY NIGHT. THIS DRIER AIR IS EXPECTED
TO STAY ACROSS THE REGION THROUGH THURSDAY WHICH WILL KEEP
SHRA/TSRA ACTIVITY TO A MINIMUM. ALL IN ALL IT LOOKS LIKE WE MAY
BE IN THE BEGINNING STAGES OF TRANSITIONING TO A MORE FALL LIKE
PATTERN...WITH FRONTS MOVING THROUGH THE STATE GIVING THE CWA
MOSTLY CLEAR SKIES FOR A FEW DAYS AND NOT STALLING ACROSS CENTRAL
OR SOUTH GA. TEMPS REMAIN IN THE MID 80S TO MID 90S THROUGH THE
EXTENDED.
01
&&
.AVIATION...
18Z UPDATE...
CONVECTION HAS BEGUN DEVELOPING ACROSS THE AREA WITH KMCN AND KCSG
ALONG MAIN LINE. SO FAR STORMS HAVE REMAINED SHOWERS BUT WE ARE
EXPECTING THUNDERSTORMS ACROSS THE TAF SITES MAINLY 19-24Z. WINDS
WILL BE NORTHWEST TO WEST AT 5-10KTS INITIALLY...DIMINISHING AFTER
00Z WITH THE LOOS OF HEATING. PATCHY FOG WILL DEVELOP IN THE USUAL
SUSPECTS AND RAIN SOAKED AREAS BY DAYBREAK WITH MVFR VISIBILITIES.
EXPECT CIGS IN MVFR/VFR RANGE THROUGH THE PERIOD.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON CIGS/TIMING OF TS
MEDIUM TO HIGH ON ALL OTHER ELEMENTS.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 71 89 71 / 50 50 30 20
ATLANTA 89 71 90 73 / 50 50 30 20
BLAIRSVILLE 82 65 84 63 / 40 40 30 20
CARTERSVILLE 89 69 91 69 / 40 50 30 10
COLUMBUS 91 74 93 75 / 40 40 20 20
GAINESVILLE 86 71 87 71 / 50 50 30 20
MACON 92 73 93 73 / 40 40 20 20
ROME 87 68 90 69 / 40 50 30 10
PEACHTREE CITY 89 70 91 71 / 50 50 30 20
VIDALIA 93 76 94 74 / 40 40 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NLISTEMAA
LONG TERM....BDL
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
949 AM EDT FRI AUG 21 2015
.UPDATE...
OLD FRONTAL BOUNDARY CURRENTLY DRAPED ACROSS CENTRAL GA THIS
MORNING. IN THE MID LEVELS...A SHEAR AXIS IS SITUATED ALMOST
DIRECTED ON TOP OF THE BOUNDARY.
WV AND 500MB RAP ANALYSIS SHOWS A WEAK WAVE SHORTWAVE ASSOCIATED
WITH THE SHOWERS ACROSS EASTERN GA THIS MORNING. THERE ARE TWO MORE
SHORTWAVES ANALYZED IN THE FLOW...ONE ACROSS CENTRAL AL AND ANOTHER
ACROSS THE ARKLAMISS. THE WAVE ACROSS CENTRAL AL SHOULD HELP SCT
CONVECTION DEVELOP THIS AFTERNOON DURING PEAK HEATING ACROSS MUCH OF
THE CWFA.
HAVE UPDATED THE POPS ACCORDING TO THE LATEST RADAR TRENDS. HAVE
ALSO TWEAKED THE AFTERNOON POPS A BIT TO COME A LITTLE MORE INTO
LINE WITH THE HRRR...WHICH HAS A PRETTY GOOD HANDLE ON THE SHRA THAT
ARE ONGOING.
LOCALLY HEAVY RAINFALL AND FREQUENT LIGHTNING STRIKES ARE THE MAIN
HAZARDS ASSOCIATED WITH ANY THUNDERSTORMS THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 718 AM EDT FRI AUG 21 2015/
PREV DISCUSSION... /ISSUED 414 AM EDT FRI AUG 21 2015/
SHORT TERM /TODAY THROUGH SATURDAY/...
NAM/GFS/ECMWF IN VERY GOOD AGREEMENT THROUGH THE SHORT TERM. SURFACE
TROUGH HAS STALLED ACROSS NORTH GEORGIA KEEPING MOST OF THE CWA IN
THE WARM AND MOIST SECTOR. THIS TROUGH WILL NOT MOVE MUCH BUT SHOULD
BE A FOCUS FOR CONVECTION THIS AFTERNOON AS A WEAK WAVE MOVES ALONG
THE BOUNDARY. AFTER THIS WAVE MOVES TO OUR EAST...THE SURFACE TROUGH
WILL SHIFT SOUTH. CAPES REMAIN IN THE 1500-2000 RANGE ALONG WITH
PWATS RANGING FROM 1.8 TO 2.1 INCHES. WILL KEEP HIGH CHANCE POPS
ACROSS NORTH AND PARTS OF CENTRAL GA WHERE THE DEEPEST MOISTURE WILL
BE WITH CHANCE POPS ELSEWHERE. CONVECTION WILL DIMINISH QUICKLY THIS
EVENING. ON SATURDAY EXPECT CONVECTION AGAIN ALTHOUGH WITH SLIGHTLY
DRIER AIR OVER THE REGION WILL LIMIT POPS TO SLIGHT CHANCE TO CHANCE
AND MAINLY DURING THE AFTERNOON. GUIDANCE TEMPS HAVE BEEN RUNNING 1
TO 2 DEGREES TOO LOW OVER THE PAST 10 DAYS AND HAVE THEREFORE RAISED
MAX TEMPS BOTH DAYS BY A DEGREE OR TWO.
17
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE EXTENDED FORECAST START OFF WITH WEAKENING BOUNDARY ACROSS
CENTRAL GA SUNDAY MOVING SOUTH. THE NEXT FRONTAL SYSTEM BEGINS TO
MOVE INTO N GA MONDAY MORNING BUT THERE IS NOT MUCH MOISTURE ASSOCIATED
WITH IT. THIS BOUNDARY WILL ACT AS A CATALYST FOR STORMS TO
DEVELOP ACROSS THE AREA MONDAY AND TUESDAY BUT IT WILL ALSO USHER
IN A MUCH DRIER AIRMASS TUESDAY NIGHT. THIS DRIER AIR IS EXPECTED
TO STAY ACROSS THE REGION THROUGH THURSDAY WHICH WILL KEEP
SHRA/TSRA ACTIVITY TO A MINIMUM. ALL IN ALL IT LOOKS LIKE WE MAY
BE IN THE BEGINNING STAGES OF TRANSITIONING TO A MORE FALL LIKE
PATTERN...WITH FRONTS MOVING THROUGH THE STATE GIVING THE CWA
MOSTLY CLEAR SKIES FOR A FEW DAYS AND NOT STALLING ACROSS CENTRAL
OR SOUTH GA. TEMPS REMAIN IN THE MID 80S TO MID 90S THROUGH THE
EXTENDED.
01
AVIATION...
12Z UPDATE...
ISOLATED LIGHT SHOWERS HAVE DEVELOPED AROUND THE ATL AREA AND WILL
ADD A VCSH IN THE ATL AREA TAFS AND ALSO AHN. VERY THIN AREAS OF
IFR CIGS ALSO AROUND THE ATL AREA AND WILL NEED TO INCLUDE SCT-BKN
IFR CIGS THIS MORNING. THERE SHOULD BE SOME INITIAL LIFTING WITH
DAYTIME HEATING WHICH WILL BRING SCT-BKN MVFR CIGS LATER THIS
MORNING BUT BECOMING VFR BY NOON. EXPECT SCATTERED TSRA TO DEVELOP
THIS AFTERNOON AND DIMINISH RAPIDLY AFTER SUNSET.
//ATL CONFIDENCE...12Z UPDATE...
LOW TO MEDIUM ON CIGS EARLY THIS MORNING
MEDIUM ON TIMING OF CONVECTION
HIGH ON REMAINING ELEMENTS
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 71 89 71 / 50 50 30 20
ATLANTA 89 71 90 73 / 50 50 30 20
BLAIRSVILLE 82 65 84 63 / 40 40 30 20
CARTERSVILLE 89 69 91 69 / 40 50 30 10
COLUMBUS 91 74 93 75 / 40 40 20 20
GAINESVILLE 86 71 87 71 / 50 50 30 20
MACON 92 73 93 73 / 40 40 20 20
ROME 87 68 90 69 / 40 50 30 10
PEACHTREE CITY 89 70 91 71 / 50 50 30 20
VIDALIA 93 76 94 74 / 40 40 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
856 PM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 856 PM CDT SAT AUG 22 2015
THE BAND OF SHOWERS AND ISOLATED STORMS ACROSS EAST CENTRAL IL HAS
DISSIPATED, WHILE A FEW SHOWERS LINGER CLOSER TO THE CENTER OF THE
SHORTWAVE SOUTH OF HIGHWAY 50. THE MAIN CONCERN THE REST OF THE
NIGHT WILL SHIFT TO THE APPROACHING COLD FRONT, THAT IS PROJECTED
TO REACH OUR WESTERN COUNTIES LATER TONIGHT. THE LATEST HRRR AND
RAP GUIDANCE SHOW A DIMINISHING TREND IN THE LINE OF STORMS AS
THEY MOVE ACROSS ILLINOIS. THE TIMING OF THE FRONTS ARRIVAL LENDS
CREDENCE TO THAT TREND, WITH LOW INSTABILITY AND WEAKENING SHEAR
PROFILES EARLY SUNDAY MORNING. WE WILL KEEP THE PROGRESSION OF A
BAND OF CHANCE POPS ACROSS OUR COUNTIES FROM WEST TO EAST LATE
TONIGHT AND SUNDAY MORNING. CONFIDENCE IS LOWERING IN A SOLID
LINE OF SHOWERS/STORMS, WITH A MORE BROKEN LINE LOOKING MORE
LIKELY.
THE DIURNAL SWING TONIGHT WILL BE TEMPERED BY INCREASING CLOUD
COVER AHEAD OF THE STORMS, AND FROM CLOUDS ASSOCIATED WITH THE
SHORTWAVE IN SOUTHERN IL. WILL KEEP LOWS IN THE MID-UPPER 60S, AS
DEWPOINTS BEGIN TO CLIMB THROUGH THE 60S.
MAIN UPDATE TONIGHT WAS TO THE WEATHER GRIDS THIS EVENING, AND TO
INCREASE CLOUD COVER TONIGHT. OTHERWISE, THE FORECAST GRIDS LOOK
REASONABLE FOR NOW.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT SAT AUG 22 2015
A WEAKENING AREA OF SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST OF
EFFINGHAM WERE AHEAD OF A SHORT WAVE TROF OVER CENTRAL MO/AR. THIS
CONVECTION WILL CONTINUE TO WEAKEN AS IT TRACKS ENE INTO SOUTHEAST
IL DURING REST OF THIS AFTERNOON AND EARLY EVENING BEFORE SUNSET.
HIGHEST POPS WERE OVER SHELBY...EFFINGHAM AND CLAY COUNTIES. MOST OF
CENTRAL IL SHOULD STAY DRY THROUGH THIS EVENING WITH PARTLY TO
MOSTLY CLOUDY SKIES. A 997 MB LOW PRESSURE OVER EAST CENTRAL ND HAS
A COLD FRONT EXTENDING INTO EASTERN SD/NEBRASKA AND NW KS. MODELS
TAKE COLD FRONT EAST TOWARD THE IA/IL BORDER AND CENTRAL MO BY 12Z/7
AM SUNDAY. CHANCES OF SHOWERS AND THUNDERSTORMS INCREASE OVER IL
RIVER VALLEY AFTER 06Z/1 AM TONIGHT AND REACH AS FAR EAST AS I-57 BY
12Z/SUNDAY WITH SLIGHT POPS IN EASTERN IL LATE TONIGHT. SPC KEEPS
MARGINAL RISK OF SEVERE STORMS WEST OF CWA (FROM QUAD CITIES TO
QUINCY WEST) TONIGHT. NUDGED LOWS UP A TAD OVERNIGHT INTO THE MID TO
UPPER 60S DUE TO MORE CLOUD COVER AND SE WINDS. COOLEST LOWS IN THE
LOWER 60S AROUND DANVILLE WHERE MET/MAV HAVE 62F.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 256 PM CDT SAT AUG 22 2015
THERE WILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS TO START THE DAY
SUNDAY ACROSS CENTRAL AND SOUTHEAST ILLINOIS AS A COLD FRONT BEGINS
TO PUSH INTO THE AREA FROM THE NORTHWEST. THE EARLY ARRIVAL OF THE
FRONT, WHICH SHOULD EXIT THE FORECAST AREA INTO INDIANA DURING THE
AFTERNOON EVEN IN THE SLOWER MODEL SOLUTIONS, WILL PRECLUDE
SIGNIFICANT PRE FRONTAL INSTABILITY. GUIDANCE STILL SUGGESTS CAPE
VALUES REACHING AROUND 2500 J/KG IN THE FAR EAST/SOUTHEAST PORTION
OF THE FORECAST AREA, BUT CORRESPONDING BULK SHEAR VALUES ARE STILL
RATHER WEAK AND TOP OUT AROUND 25 KTS. SO, DO NOT EXPECT MORE THAN
SCATTERED SHOWERS/STORMS ACROSS THE FORECAST AREA AHEAD OF THE
FRONT, WITH PRECIPITATION QUICKLY ENDING FROM WEST TO EAST DURING
THE AFTERNOON AS THE FRONT SWEEPS THROUGH.
THE UPPER LEVEL FLOW ACROSS THE AREA TRENDS NORTHWESTERLY BEHIND
SUNDAY`S SYSTEM, ALBEIT MOSTLY NEUTRAL LOCALLY, AS UPPER RIDGING
BUILDS THROUGH THE ROCKIES. THIS UPPER FLOW PATTERN IS ACCOMPANIED
BY HIGH PRESSURE AT THE SURFACE MORE OFTEN THAN NOT, AND THESE
FEATURES SHOULD HELP KEEP CONDITIONS QUIET AND SLIGHTLY COOLER THAN
NORMAL. MODEL GUIDANCE NOT IN VERY GOOD AGREEMENT IN WHEN THE NEXT
DISTURBANCE OF CONSEQUENCE WILL IMPACT THE AREA IN THIS FLOW REGIME,
BUT IT DOES NOT APPEAR AS THOUGH IT WILL ARRIVE MUCH SOONER THAN
NEXT SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 656 PM CDT SAT AUG 22 2015
SHOWERS AND ISOLATED THUNDERSTORMS ARE BEING PERSISTENT ACROSS OUR
EAST CENTRAL COUNTIES, NEAR DEC AND HEADED TOWARD CMI. THE SEEM TO
BE ASSOCIATED WITH A COMPACT SHORTWAVE THAT IS GENERALLY MOVING
EASTWARD ACROSS SOUTHERN IL, BUT A LINE OF CONVECTION IS DRIFTING
E-NE ACROSS OUR AREA. WILL INCLUDE THUNDER AT DEC THROUGH 02Z, BUT
LEAVE THUNDER OUT OF CMI FOR NOW. THE GENERAL TREND EARLIER THIS
EVENING WAS TOWARD SOME WEAKENING, SO WILL MONITOR TRENDS THE NEXT
HOUR FOR POSSIBLE MENTION OF THUNDER AT CMI. BETWEEN 01-02Z.
CLOUD HEIGHTS HAVE DIPPED TO MVFR AT SPI...WITH VFR LEVELS AT ALL
OTHER TERMINAL SITES. UPSTREAM TRENDS SHOW VFR CONDITIONS SHOULD
RETURN FOR LATE EVENING.
SHOWERS AND STORMS WILL APPROACH LATER TONIGHT FOR PIA (08Z) AND
SPI (09Z), AS A COLD FRONT APPROACHES FROM THE NW. A LINE OF
SHOWERS/STORMS IS EXPECTED TO PROGRESS ACROSS IL, WITHIN A GENERAL
WINDOW OF 3-5 HOURS. NO SEVERE WEATHER IS EXPECTED, AS SHEAR
VALUES REMAIN LOW, AND INSTABILITY MARGINAL.
CLEARING IS EXPECTED TO DEVELOP BY SUNDAY AFTERNOON FOR PIA, WITH
CLEARING WORKING EASTWARD TO CMI BY 22Z.
WINDS WILL START OUT SOUTHEAST THIS EVENING AT LESS THAN 10KT,
THEN BECOME SOUTH AHEAD OF THE LINE OF PRECIP. ONCE THE COLD FRONT
PASSES SUNDAY MORNING, WINDS WILL BECOME W-NW AND INCREASE TO
10-14KT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHIMON
SHORT TERM...07
LONG TERM...BAK
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
121 PM CDT FRI AUG 21 2015
.SHORT TERM /TODAY/...
ISSUED AT 346 AM CDT FRI AUG 21 2015
MAIN FORECAST CONCERN WAS FOCUSED ON TEMPERATURES AND WINDS FOR
THIS AFTERNOON...AND WITH WEAK SHORTWAVE PROVIDING SOME ISOLATED
SHOWERS/STORMS THROUGH THE MID-MORNING. A FEW ELEVATED
SHOWERS/STORMS HAVE DEVELOPED OVER WEST-CENTRAL TO NORTHWEST IOWA
AND LOOK TO MEANDER INTO NORTH-CENTRAL IOWA THROUGH 15Z THIS
MORNING. THERE IS ENOUGH FORCING AND ELEVATED INSTABILITY...ALBEIT
VERY WEAK...BUT ENOUGH TO WARRANT SLIGHT/LOW CHANCE POPS OVER THE
NORTH. HOWEVER WITH A A STRONG CAP IN PLACE TODAY...IT WILL LIMIT
ANYTHING PAST 15Z. THE LATEST 21.07Z HRRR HAS A DECENT HANDLE ON
THE CONVECTIVE TRENDS AND LEANED TOWARD ITS SOLUTION FOR POPS/WX.
STRONG MIXING AND WAA DEVELOP TODAY AS PRESSURE GRADIENT TIGHTENS
THIS AFTERNOON. MIXING TO AROUND 850MB PUTS HIGHS IN THE LOWER 80S
AND TWEAKED MAX TEMPS UP SLIGHTLY. THE MAV/ECS HAD A GREAT HANDLE
ON TEMPS TODAY AS THE MET WAS TOO COLD THROUGHOUT THE FORECAST
AREA. ALSO TWEAKED UP WINDS SLIGHTLY AS WINDS ATOP THE MIXED LAYER
IN THE 25-30 KNOT RANGE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 346 AM CDT FRI AUG 21 2015
THE LONG TERM FORECAST IS CHARACTERIZED BY VARYING TEMPERATURES
AND MOSTLY DRY CONDITIONS BUT PUNCTUATED AND HEADLINED BY THE
STORM SYSTEM MOVING ACROSS THE REGION ON SATURDAY AND SATURDAY
NIGHT. THE DRIVER FOR THIS SYSTEM WILL COME IN THE FORM OF A
MID/UPPER LEVEL TROUGH...STRONG FOR THIS SEASON...MOVING ACROSS
THE NORTHERN ROCKIES ON FRIDAY NIGHT AND OVER THE DAKOTAS AND
MINNESOTA ON SATURDAY AND SATURDAY NIGHT. THIS WILL BE REFLECTED
AT THE SURFACE BY A STEADILY STRENGTHENING
TROUGH/FRONT...INITIALLY STRETCHING DOWN THE HIGH PLAINS AND THEN
SWEEPING EAST/SOUTHEAST IN RESPONSE TO THE PROGRESSION OF THE
MID/UPPER TROUGH ON SATURDAY/SATURDAY NIGHT. AHEAD OF THIS SYSTEM
MOST OF SATURDAY WILL BE WARM AND INCREASINGLY BREEZY ACROSS OUR
FORECAST AREA AS THE SURFACE PRESSURE GRADIENT TIGHTENS UP
BETWEEN THE HIGH PLAINS TROUGH AND A LARGE HIGH PRESSURE AREA
DEPARTING TO THE EAST. FOR MUCH OF THE DAY THINGS WILL REMAIN
QUIET...BUT BY PEAK HEATING IN THE LATE AFTERNOON/EVENING
INSTABILITY WILL BE MAXIMIZED AND THE SURFACE FRONT WILL SERVE AS
A MECHANISM FOR THUNDERSTORM DEVELOPMENT COINCIDENT WITH THE
ARRIVAL OF STRONGER FORCING AND WIND FIELDS ALOFT GIVEN THE
APPROACH OF THE MID/UPPER TROUGH. INITIAL STORMS WILL LIKELY BE
ORGANIZED WITHIN THIS ENVIRONMENT PROVIDING A FAIRLY SUBSTANTIAL
SEVERE WEATHER THREAT...THEN AS THE SYSTEM MOVES EAST/SOUTHEAST
WITH SUNSET THE STORMS SHOULD BECOME MORE LINEAR AND GRADUALLY
DIMINISH IN INTENSITY BY THE TIME THEY REACH EASTERN IOWA. FOR NOW
THE PRIMARY QUESTIONS ARE WHERE THE STORMS WILL INITIALLY
DEVELOP...OVER SOUTH DAKOTA/MINNESOTA/NEBRASKA OR OVER
WESTERN/NORTHWESTERN IOWA...AND HOW FAR EAST/SOUTHEAST THEY WILL
REMAIN SEVERE AS THEY MOVE QUICKLY ACROSS THE STATE. SPC PRODUCTS
HANDLE THE THREAT WELL AND WILL BE CLOSELY MONITORED TODAY AND
TOMORROW.
AFTER THE FRONT AND ASSOCIATED STORMS BLOW THROUGH ON SATURDAY
NIGHT WE WILL ONCE AGAIN SEE MOSTLY CLEAR...COOL...AND BREEZY
WEATHER FROM SUNDAY INTO EARLY NEXT WEEK. BY MONDAY THE 500 MB
PATTERN WILL FEATURE A DEEPENING GYRE OVER THE GREAT LAKES
REGION...THAT BEING THE SYSTEM THAT AFFECTED US ON
SATURDAY/SATURDAY NIGHT...WITH A DEVELOPING RIDGE OVER THE FOUR
CORNERS REGION. INITIALLY THIS WILL PLACE IOWA BENEATH PERSISTENT
NORTHWEST FLOW RESULTING IN A VERY SLOW WARMING TREND. BY MIDWEEK
AS THE EASTERN GYRE DEPARTS THE WESTERN RIDGE WILL BUILD FURTHER
AND APPROACH OUR AREA...BUT MOST OF THE HEAT BUBBLE SHOULD REMAIN
WEST/SOUTHWEST OF IOWA THROUGH AT LEAST WEDNESDAY. THERE ARE
CONSISTENT INDICATIONS THAT A SHORTWAVE WILL OVERTOP THE 500 MB
RIDGE SOMETIME AROUND THURSDAY...POSSIBLY PROVIDING US WITH
ANOTHER CHANCE FOR RAIN BUT MORE IMPORTANTLY SHUNTING THE RIDGE
SOUTHWARD FOR A DAY OR TWO. BEYOND THIS...LOOKING TOWARD THE NEXT
WEEKEND OR SO...IT REMAINS UNCERTAIN WHETHER THE LARGE RIDGE WILL
BE ABLE TO BUILD UP OVER THE MIDWEST OR WILL REMAIN JUST TO OUR
SOUTHWEST. THIS WILL DETERMINE WHETHER WE GET ONE LAST BLAST OF
SUMMER HEAT OR NOT.
&&
.AVIATION...21/18Z
ISSUED AT 119 PM CDT FRI AUG 21 2015
GENERALLY VFR CONDITIONS THROUGH THE PERIOD. LOW POTENTIAL FOR
STRATUS DEVELOPING OVERNIGHT HOWEVER WINDS SHOULD REMAIN STRONG
ENOUGH TO KEEP THIS POTENTIAL AT A MINIMUM. OTHERWISE BREEZY
SOUTHERLY WINDS TODAY DIMINISHING OVERNIGHT THEN INCREASING AGAIN
SATURDAY MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...LEE
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
650 AM CDT FRI AUG 21 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
ISSUED AT 346 AM CDT FRI AUG 21 2015
MAIN FORECAST CONCERN WAS FOCUSED ON TEMPERATURES AND WINDS FOR
THIS AFTERNOON...AND WITH WEAK SHORTWAVE PROVIDING SOME ISOLATED
SHOWERS/STORMS THROUGH THE MID-MORNING. A FEW ELEVATED
SHOWERS/STORMS HAVE DEVELOPED OVER WEST-CENTRAL TO NORTHWEST IOWA
AND LOOK TO MEANDER INTO NORTH-CENTRAL IOWA THROUGH 15Z THIS
MORNING. THERE IS ENOUGH FORCING AND ELEVATED INSTABILITY...ALBEIT
VERY WEAK...BUT ENOUGH TO WARRANT SLIGHT/LOW CHANCE POPS OVER THE
NORTH. HOWEVER WITH A A STRONG CAP IN PLACE TODAY...IT WILL LIMIT
ANYTHING PAST 15Z. THE LATEST 21.07Z HRRR HAS A DECENT HANDLE ON
THE CONVECTIVE TRENDS AND LEANED TOWARD ITS SOLUTION FOR POPS/WX.
STRONG MIXING AND WAA DEVELOP TODAY AS PRESSURE GRADIENT TIGHTENS
THIS AFTERNOON. MIXING TO AROUND 850MB PUTS HIGHS IN THE LOWER 80S
AND TWEAKED MAX TEMPS UP SLIGHTLY. THE MAV/ECS HAD A GREAT HANDLE
ON TEMPS TODAY AS THE MET WAS TOO COLD THROUGHOUT THE FORECAST
AREA. ALSO TWEAKED UP WINDS SLIGHTLY AS WINDS ATOP THE MIXED LAYER
IN THE 25-30 KNOT RANGE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 346 AM CDT FRI AUG 21 2015
THE LONG TERM FORECAST IS CHARACTERIZED BY VARYING TEMPERATURES
AND MOSTLY DRY CONDITIONS BUT PUNCTUATED AND HEADLINED BY THE
STORM SYSTEM MOVING ACROSS THE REGION ON SATURDAY AND SATURDAY
NIGHT. THE DRIVER FOR THIS SYSTEM WILL COME IN THE FORM OF A
MID/UPPER LEVEL TROUGH...STRONG FOR THIS SEASON...MOVING ACROSS
THE NORTHERN ROCKIES ON FRIDAY NIGHT AND OVER THE DAKOTAS AND
MINNESOTA ON SATURDAY AND SATURDAY NIGHT. THIS WILL BE REFLECTED
AT THE SURFACE BY A STEADILY STRENGTHENING
TROUGH/FRONT...INITIALLY STRETCHING DOWN THE HIGH PLAINS AND THEN
SWEEPING EAST/SOUTHEAST IN RESPONSE TO THE PROGRESSION OF THE
MID/UPPER TROUGH ON SATURDAY/SATURDAY NIGHT. AHEAD OF THIS SYSTEM
MOST OF SATURDAY WILL BE WARM AND INCREASINGLY BREEZY ACROSS OUR
FORECAST AREA AS THE SURFACE PRESSURE GRADIENT TIGHTENS UP
BETWEEN THE HIGH PLAINS TROUGH AND A LARGE HIGH PRESSURE AREA
DEPARTING TO THE EAST. FOR MUCH OF THE DAY THINGS WILL REMAIN
QUIET...BUT BY PEAK HEATING IN THE LATE AFTERNOON/EVENING
INSTABILITY WILL BE MAXIMIZED AND THE SURFACE FRONT WILL SERVE AS
A MECHANISM FOR THUNDERSTORM DEVELOPMENT COINCIDENT WITH THE
ARRIVAL OF STRONGER FORCING AND WIND FIELDS ALOFT GIVEN THE
APPROACH OF THE MID/UPPER TROUGH. INITIAL STORMS WILL LIKELY BE
ORGANIZED WITHIN THIS ENVIRONMENT PROVIDING A FAIRLY SUBSTANTIAL
SEVERE WEATHER THREAT...THEN AS THE SYSTEM MOVES EAST/SOUTHEAST
WITH SUNSET THE STORMS SHOULD BECOME MORE LINEAR AND GRADUALLY
DIMINISH IN INTENSITY BY THE TIME THEY REACH EASTERN IOWA. FOR NOW
THE PRIMARY QUESTIONS ARE WHERE THE STORMS WILL INITIALLY
DEVELOP...OVER SOUTH DAKOTA/MINNESOTA/NEBRASKA OR OVER
WESTERN/NORTHWESTERN IOWA...AND HOW FAR EAST/SOUTHEAST THEY WILL
REMAIN SEVERE AS THEY MOVE QUICKLY ACROSS THE STATE. SPC PRODUCTS
HANDLE THE THREAT WELL AND WILL BE CLOSELY MONITORED TODAY AND
TOMORROW.
AFTER THE FRONT AND ASSOCIATED STORMS BLOW THROUGH ON SATURDAY
NIGHT WE WILL ONCE AGAIN SEE MOSTLY CLEAR...COOL...AND BREEZY
WEATHER FROM SUNDAY INTO EARLY NEXT WEEK. BY MONDAY THE 500 MB
PATTERN WILL FEATURE A DEEPENING GYRE OVER THE GREAT LAKES
REGION...THAT BEING THE SYSTEM THAT AFFECTED US ON
SATURDAY/SATURDAY NIGHT...WITH A DEVELOPING RIDGE OVER THE FOUR
CORNERS REGION. INITIALLY THIS WILL PLACE IOWA BENEATH PERSISTENT
NORTHWEST FLOW RESULTING IN A VERY SLOW WARMING TREND. BY MIDWEEK
AS THE EASTERN GYRE DEPARTS THE WESTERN RIDGE WILL BUILD FURTHER
AND APPROACH OUR AREA...BUT MOST OF THE HEAT BUBBLE SHOULD REMAIN
WEST/SOUTHWEST OF IOWA THROUGH AT LEAST WEDNESDAY. THERE ARE
CONSISTENT INDICATIONS THAT A SHORTWAVE WILL OVERTOP THE 500 MB
RIDGE SOMETIME AROUND THURSDAY...POSSIBLY PROVIDING US WITH
ANOTHER CHANCE FOR RAIN BUT MORE IMPORTANTLY SHUNTING THE RIDGE
SOUTHWARD FOR A DAY OR TWO. BEYOND THIS...LOOKING TOWARD THE NEXT
WEEKEND OR SO...IT REMAINS UNCERTAIN WHETHER THE LARGE RIDGE WILL
BE ABLE TO BUILD UP OVER THE MIDWEST OR WILL REMAIN JUST TO OUR
SOUTHWEST. THIS WILL DETERMINE WHETHER WE GET ONE LAST BLAST OF
SUMMER HEAT OR NOT.
&&
.AVIATION...21/12Z
ISSUED AT 648 AM CDT FRI AUG 21 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. ONLY CONCERN
IS WITH GUSTY WINDS LATE THIS MORNING INTO THE AFTERNOON...AND
SUSTAINED WINDS ARE EXPECTED TO PERSIST TONIGHT INTO TOMORROW
MORNING WITH A DECENT PRESSURE GRADIENT ACROSS THE STATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...LEE
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
346 AM CDT FRI AUG 21 2015
.SHORT TERM /TODAY/...
ISSUED AT 346 AM CDT FRI AUG 21 2015
MAIN FORECAST CONCERN WAS FOCUSED ON TEMPERATURES AND WINDS FOR
THIS AFTERNOON...AND WITH WEAK SHORTWAVE PROVIDING SOME ISOLATED
SHOWERS/STORMS THROUGH THE MID-MORNING. A FEW ELEVATED
SHOWERS/STORMS HAVE DEVELOPED OVER WEST-CENTRAL TO NORTHWEST IOWA
AND LOOK TO MEANDER INTO NORTH-CENTRAL IOWA THROUGH 15Z THIS
MORNING. THERE IS ENOUGH FORCING AND ELEVATED INSTABILITY...ALBEIT
VERY WEAK...BUT ENOUGH TO WARRANT SLIGHT/LOW CHANCE POPS OVER THE
NORTH. HOWEVER WITH A A STRONG CAP IN PLACE TODAY...IT WILL LIMIT
ANYTHING PAST 15Z. THE LATEST 21.07Z HRRR HAS A DECENT HANDLE ON
THE CONVECTIVE TRENDS AND LEANED TOWARD ITS SOLUTION FOR POPS/WX.
STRONG MIXING AND WAA DEVELOP TODAY AS PRESSURE GRADIENT TIGHTENS
THIS AFTERNOON. MIXING TO AROUND 850MB PUTS HIGHS IN THE LOWER 80S
AND TWEAKED MAX TEMPS UP SLIGHTLY. THE MAV/ECS HAD A GREAT HANDLE ON
TEMPS TODAY AS THE MET WAS TOO COLD THROUGHOUT THE FORECAST AREA.
ALSO TWEAKED UP WINDS SLIGHTLY AS WINDS ATOP THE MIXED LAYER IN THE
25-30 KNOT RANGE.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 346 AM CDT FRI AUG 21 2015
THE LONG TERM FORECAST IS CHARACTERIZED BY VARYING TEMPERATURES
AND MOSTLY DRY CONDITIONS BUT PUNCTUATED AND HEADLINED BY THE
STORM SYSTEM MOVING ACROSS THE REGION ON SATURDAY AND SATURDAY
NIGHT. THE DRIVER FOR THIS SYSTEM WILL COME IN THE FORM OF A
MID/UPPER LEVEL TROUGH...STRONG FOR THIS SEASON...MOVING ACROSS
THE NORTHERN ROCKIES ON FRIDAY NIGHT AND OVER THE DAKOTAS AND
MINNESOTA ON SATURDAY AND SATURDAY NIGHT. THIS WILL BE REFLECTED
AT THE SURFACE BY A STEADILY STRENGTHENING
TROUGH/FRONT...INITIALLY STRETCHING DOWN THE HIGH PLAINS AND THEN
SWEEPING EAST/SOUTHEAST IN RESPONSE TO THE PROGRESSION OF THE
MID/UPPER TROUGH ON SATURDAY/SATURDAY NIGHT. AHEAD OF THIS SYSTEM
MOST OF SATURDAY WILL BE WARM AND INCREASINGLY BREEZY ACROSS OUR
FORECAST AREA AS THE SURFACE PRESSURE GRADIENT TIGHTENS UP
BETWEEN THE HIGH PLAINS TROUGH AND A LARGE HIGH PRESSURE AREA
DEPARTING TO THE EAST. FOR MUCH OF THE DAY THINGS WILL REMAIN
QUIET...BUT BY PEAK HEATING IN THE LATE AFTERNOON/EVENING
INSTABILITY WILL BE MAXIMIZED AND THE SURFACE FRONT WILL SERVE AS
A MECHANISM FOR THUNDERSTORM DEVELOPMENT COINCIDENT WITH THE
ARRIVAL OF STRONGER FORCING AND WIND FIELDS ALOFT GIVEN THE
APPROACH OF THE MID/UPPER TROUGH. INITIAL STORMS WILL LIKELY BE
ORGANIZED WITHIN THIS ENVIRONMENT PROVIDING A FAIRLY SUBSTANTIAL
SEVERE WEATHER THREAT...THEN AS THE SYSTEM MOVES EAST/SOUTHEAST
WITH SUNSET THE STORMS SHOULD BECOME MORE LINEAR AND GRADUALLY
DIMINISH IN INTENSITY BY THE TIME THEY REACH EASTERN IOWA. FOR NOW
THE PRIMARY QUESTIONS ARE WHERE THE STORMS WILL INITIALLY
DEVELOP...OVER SOUTH DAKOTA/MINNESOTA/NEBRASKA OR OVER
WESTERN/NORTHWESTERN IOWA...AND HOW FAR EAST/SOUTHEAST THEY WILL
REMAIN SEVERE AS THEY MOVE QUICKLY ACROSS THE STATE. SPC PRODUCTS
HANDLE THE THREAT WELL AND WILL BE CLOSELY MONITORED TODAY AND
TOMORROW.
AFTER THE FRONT AND ASSOCIATED STORMS BLOW THROUGH ON SATURDAY
NIGHT WE WILL ONCE AGAIN SEE MOSTLY CLEAR...COOL...AND BREEZY
WEATHER FROM SUNDAY INTO EARLY NEXT WEEK. BY MONDAY THE 500 MB
PATTERN WILL FEATURE A DEEPENING GYRE OVER THE GREAT LAKES
REGION...THAT BEING THE SYSTEM THAT AFFECTED US ON
SATURDAY/SATURDAY NIGHT...WITH A DEVELOPING RIDGE OVER THE FOUR
CORNERS REGION. INITIALLY THIS WILL PLACE IOWA BENEATH PERSISTENT
NORTHWEST FLOW RESULTING IN A VERY SLOW WARMING TREND. BY MIDWEEK
AS THE EASTERN GYRE DEPARTS THE WESTERN RIDGE WILL BUILD FURTHER
AND APPROACH OUR AREA...BUT MOST OF THE HEAT BUBBLE SHOULD REMAIN
WEST/SOUTHWEST OF IOWA THROUGH AT LEAST WEDNESDAY. THERE ARE
CONSISTENT INDICATIONS THAT A SHORTWAVE WILL OVERTOP THE 500 MB
RIDGE SOMETIME AROUND THURSDAY...POSSIBLY PROVIDING US WITH
ANOTHER CHANCE FOR RAIN BUT MORE IMPORTANTLY SHUNTING THE RIDGE
SOUTHWARD FOR A DAY OR TWO. BEYOND THIS...LOOKING TOWARD THE NEXT
WEEKEND OR SO...IT REMAINS UNCERTAIN WHETHER THE LARGE RIDGE WILL
BE ABLE TO BUILD UP OVER THE MIDWEST OR WILL REMAIN JUST TO OUR
SOUTHWEST. THIS WILL DETERMINE WHETHER WE GET ONE LAST BLAST OF
SUMMER HEAT OR NOT.
&&
.AVIATION...21/06Z
ISSUED AT 1149 PM CDT THU AUG 20 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD WITH MID
CLOUDS TO MOVE IN OVERNIGHT. STILL SOME ISOLATED SHRA/TSRA
POSSIBLE LATE TONIGHT INTO EARLY FRIDAY...COULD IMPACT KFOD AND
KMCW. STILL HAVE LEFT OUT OF THE TAF GIVEN THE UNCERTAINTY AND
WIDELY SCATTERED NATURE OF THE EXPECTED STORMS. SOUTHERLY WINDS TO
PICK UP FRIDAY...AND DIMINISH AGAIN FRIDAY EVENING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...LEE
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
241 PM MDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 1003 AM MDT FRI AUG 21 2015
CURRENT FORECAST FOR THE AFTERNOON AND EVENING LOOKS ON TRACK
WITH THE LATEST OBSERVATIONS AND MODEL DATA. DID ADJUST THE
COVERAGE AND VALUE OF THE RAINFALL CHANCES A BIT GIVEN THE GOOD
AGREEMENT AMONG THE MODELS FOR THE STORM ACTIVITY THIS AFTERNOON.
EXPECT STORMS TO DEVELOP ALONG A SURFACE TROUGH/DRY LINE OVER THE
WESTERN PART OF THE AREA. THE STRONGEST LIFT WILL REMAIN TIED
TO THE NEARLY STATIONARY TROUGH THROUGH THE AFTERNOON...SO EXPECT
STORMS TO DEVELOP ALONG IT AND MOVE SLOWLY EAST. THE MAIN QUESTION
WILL BE HOW FAR EAST WILL THE STORMS GO BEFORE DISSIPATING SINCE
THE MAJORITY OF THE LIFT WILL REMAIN WITH THE SURFACE TROUGH.
CURRENTLY LOOKS LIKE THE MAJORITY OF THE STORMS WILL WEAKEN BY THE
TIME THEY REACH THE HIGHWAY 83 CORRIDOR...ALTHOUGH STORMS WHICH
MOVE OVER SOUTHWEST NEBRASKA MAY MAKE IT ALL THE WAY THROUGH RED
WILLOW COUNTY BEFORE DISSIPATING.
FOR THE EVENING AM NOT TOO CONFIDENT REGARDING STORMS EAST OF
HIGHWAY 25. AM THINKING ONCE THE SURFACE HEATING ENDS THE NOSE OF
THE LOW LEVEL JET WILL SERVE AS THE PRIMARY TRIGGER FOR
STORMS...WHICH WILL BE PRIMARILY WEST OF HIGHWAY 27. HOWEVER
SOUNDINGS INDICATE A FAIRLY DRY ENVIRONMENT DURING THE
EVENING WEST OF HIGHWAY 27...WHICH MAY HINDER STORM DEVELOPMENT
DESPITE THE INFLUENCE OF THE NOSE OF THE LOW LEVEL JET.
ASIDE FROM THE STORMS DID INCREASE THE WINDS DUE TO THE
STRENGTHENING LOW LEVEL JET IN THE AFTERNOON MIXING TO THE GROUND.
WEST OF THE SURFACE TROUGH THE WINDS WILL BE LIGHT DUE TO THE LOW.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 330 AM MDT FRI AUG 21 2015
FORECAST CONCERNS WILL BE THUNDERSTORM CHANCES INTO THE BEGINNING OF
THE WEEKEND AND HOW COOL TO MAKE IT SATURDAY NIGHT INTO SUNDAY
NIGHT. SATELLITE SHOWING AN AMPLIFIED/BLOCKY OVER THE PACIFIC. THIS
TRANSITIONS TO A BROAD TROUGH/WESTERLY ALOFT OVER MOST OF THE
COUNTRY. STRONG SYSTEM DIGGING INTO SOUTHWEST CANADA WITH SEVERAL
SHORTWAVE TROUGHS EMBEDDED IN THE WESTERLY FLOW.
AT JET LEVEL...MODELS DID WELL. AT MID LEVELS...THE GFS/CANADIAN AND
THE UKMET WERE DOING A LITTLE BETTER THAN THE ECMWF. THE SREF AND
ESPECIALLY THE NAM WERE NOT DOING WELL. THE GFS WAS DOING A LITTLE
BETTER THAN THE ECMWF WITH THE LOW LEVEL WIND FIELD. ALL MODELS
INITIALIZED WELL ON THE LOW LEVEL THERMAL FIELD
DIFFICULT AND UNCERTAIN PRECIPITATION FORECAST...ESPECIALLY
THROUGH THIS EVENING. CONFIDENCE IS BELOW AVERAGE FOR THE
PRECIPITATION FORECAST.
TODAY/TONIGHT...WILL HAVE TO KEEP AN EYE ON ANY LATE NIGHT/EARLY
MORNING DEVELOPMENT NEAR THE BOUNDARY JUST TO THE NORTH OF OUR
AREA. MODELS HAVE BEEN HINTING AT IT AND WILL CONTINUE TO MONITOR.
FOR YESTERDAYS THUNDERSTORMS...JUST ENOUGH MOISTURE ALONG A
BOUNDARY WITH A WEAK SHORTWAVE TROUGH WAS ABLE TO SPARK ISOLATED
THUNDERSTORMS OVER AND NEAR THE NORTHEAST PORTION OF THE AREA. NOT
TOO DIFFERENT A SETUP FOR TODAY FROM YESTERDAY. AGAIN WHAT MAKES
FORECAST UNCERTAIN IS THE MOISTURE AVAILABILITY...ESPECIALLY
ABOVE THE LOW LEVELS...WHERE DOES THE SURFACE TROUGH SETUP AND THE
WEAK/COMPLICATED MID LEVEL FORCING INVOLVED.
MODELS HAVE THE BOUNDARY PRETTY CLOSE BUT A LITTLE FURTHER WEST THAN
WHAT WAS SHOWN YESTERDAY. 700 MB SHORTWAVE EJECTS INTO THE PLAINS THIS
AFTERNOON AND IT LOOKS TO BE IN TWO PIECES. ONE PORTION GOES
ACROSS THE NORTH AND IS THE SLOWER OF THE TWO SHORTWAVE TROUGHS.
THE SECOND ONE GOES ACROSS TO OUR SOUTH AND BRUSHES THE SOUTHERN
PORTION OF THE AREA. THERE IS WEAK FORCING IN BETWEEN. ALSO THE
MODELS DIFFER ON HOW FAR EAST DURING THE DAY THEY MOVE THESE
SHORTWAVE TROUGHS.
CONVECTIVE ALLOWING MODELS ARE HAVING A DIFFICULT WITH ALL THIS. THE
ARW HAS LITTLE TO NOTHING. THE HRRR AND ESPECIALLY THE NMM DEVELOP
ROBUST CONVECTION OVER THE WESTERN PORTION OF THE AREA THIS
AFTERNOON CLOSE TO THE SURFACE TROUGH. THE 00Z NAM DID NOT INDICATE
ANYTHING BUT NOW THE 06Z NAM IS MATCHING UP WITH THE ABOVE TWO
MODELS. THE 00Z ECMWF EXPLODES CONVECTION OVER THE NORTHERN PORTION
OF THE AREA. ALL THIS TIME A RATHER STOUT EML LIES OVER THE AREA.
AFTER LOOKING AT THIS AND COLLABORATION...PULLED THE INITIATION A
LITTLE FURTHER WEST THAN BEFORE. THE PROBLEM THEN BECOMES HOW FAR
EAST TO TAKE THIS ACTIVITY. THE HRRR TAKES IT FURTHER EAST WHILE THE
REST OF THE OUTPUT THAT DID DEVELOP SOMETHING JUST KEEPS IT OVER
THE WEST AS IT EITHER DISSIPATES THE THUNDERSTORMS OR MOVES THEM
OF THE AREA TO THE NORTH OR SOUTH. SO DID LOWER POPS A LITTLE DUE
TO THIS.
IT DOES LOOK LIKE THE THUNDERSTORMS END BY 06Z. HOWEVER ELEVATED
STORMS/REDEVELOPMENT WILL NEED TO BE LOOKED AT AGAIN TO A LOW LEVEL
JET AND DECENT WARM AIR ADVECTION PATTERN ALOFT AHEAD OF ANOTHER
SHORTWAVE TROUGH. FOR THIS AFTERNOON AND EVENINGS CONVECTION...IF
STORMS DEVELOP...IT WILL BE POSSIBLE THAT THESE WILL BECOME SEVERE
DUE TO THE INSTABILITY AND LAPSE RATES INVOLVED. NO MATTER IF
STORMS DEVELOP OR NOT...BOUNDARY LAYER MOISTURE INCREASES AND AT
THE VERY LEAST A LOT OF STRATUS WILL DEVELOP WITH SOME PATCHY FOG
INVOLVED.
PRESSURE FALLS AND GRADIENT SUPPORT NEAR BREEZY OR BREEZY CONDITIONS.
GUIDANCE HAS BEEN RUNNING COOL ON MAXES HERE THE LAST FEW DAYS.
THE GFS/MAV HAS BEEN DOING THE BEST AND HAVE RAISED THE MAXES SOME.
SATURDAY/SATURDAY NIGHT...PATCHY FOG ENDS BY MID MORNING WITH THE
STRATUS LASTING A LITTLE LONGER. THERE ARE STILL DIFFERENCES IN
HOW FAST THE MODELS BRING IN THE COLD FRONT. THE NAM IS THE
SLOWEST FOLLOWED BY SREF. THE GFS/ECMWF/CANADIAN ARE THE FASTEST.
ROUGHLY IT LOOKS LIKE THE FRONT IS THROUGH THE NORTHWEST HALF OF
THE AREA BY LATE MORNING. THE FRONT THEN LOOKS TO MOVE ACROSS THE
REST OF THE AREA BY LATE AFTERNOON OR EARLY EVENING.
THE CHANCE OF THUNDERSTORMS WILL BE OVER THE SOUTHEAST PORTION OF
THE AREA IN ADVANCE OF THIS FRONT. CONTINUED THE LOW CHANCE POPS IN
THIS AREA. FRONT AND ASSOCIATED FORCING EXIT THE AREA EARLY IN
THE EVENING AND SO PRECIPITATION CUTS OFF RATHER FAST.
WINDS BEHIND THE FRONT COULD GET WINDY AND THE DAY SHIFT WILL NEED
TO LOOK AT RAISING THE WINDS EVEN MORE. DESPITE SIMILAR TIMING TO
YESTERDAYS OUTPUT...MODELS HAVE RAISED HIGH TEMPERATURES FOR THE
DAY. THE GFS...CANADIAN AND THE NAM ARE IN DECENT AGREEMENT ON
THIS. IT SEEMS THAT THE COLDER AIR DOES LAG SLIGHTLY BEHIND THE
FRONT. DID RAISE MAXES A LITTLE BUT THEY MAY NEED TO BE RAISED
EVEN MORE IN SOUTHERN LOCATIONS.
WINDS STAY UP ENOUGH TONIGHT THAT TEMPERATURES SHOULD NOT DROP
LIKE A ROCK. IF THE WINDS LET UP QUICKER...GOOD RADIATIONAL
CONDITIONS WOULD BE IN PLACE AND A LOWERING OF THE MINS WOULD BE
NEEDED.
SUNDAY/SUNDAY NIGHT...DRY PERIOD WITH POST FRONTAL COOL AIR MASS IN
PLACE. NEW GUIDANCE FOR TEMPERATURES VERY SIMILAR TO WHAT WAS IN
THERE FOR MAXES AND MADE ONLY SLIGHT ADJUSTMENTS. ONCE AGAIN FOR THE
MINS...IF WINDS END UP BEING LESS THAN CURRENTLY PREDICTED ADDITIONAL
COOLING WILL BE NEEDED.
.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 241 PM MDT FRI AUG 21 2015
FOR THIS RUN OF THE EXTENDED FORECAST...THE PRIMARY SENSIBLE WEATHER
TO FOCUS ON WILL BE SATURDAY INTO SATURDAY NIGHT AS A COLD FRONT
PASSES AND THUNDERSTORM DEVELOPMENT OCCURS.
BEGINNING SATURDAY MORNING...A COLD FRONT SHOULD BEGIN SLIDING INTO
THE FORECAST AREA. AHEAD OF THE FRONT...AMPLE MIXING WILL LEAD TO A
FAST RISE IN THE TEMPERATURES BEFORE THE FRONT MOVES THROUGH.
THEREFORE...HIGH TEMPERATURE FORECAST IS TRICKY BECAUSE OF QUESTIONS
ON THE DEGREE OF WARMING AND FRONT TIMING. AHEAD OF THE COLD
FRONT...A MOIST AND UNSTABLE AIRMASS WILL BE IN PLACE. THE STORM
ENVIRONMENT SHOULD BE CHARACTERIZED BY SBCAPE OF 2000-3500
J/KG...850-500 MB LAPSE RATES OF 8-9 C/KM...0-6 KM BULK SHEAR NEAR
30 KTS...INCREASING IN THE EVENING. THIS MEANS A FEW STRONG/SEVERE
STORMS ARE POSSIBLE AHEAD OF THE FRONT. THE LOCATIONS UNDER THE
HIGHEST THREAT FOR STORMS/SEVERE WEATHER LIE ALONG AND SOUTH OF A
LINE FROM HILL CITY KANSAS TO OAKLEY TO KIT CARSON COLORADO. THE
PRIMARY THREATS WILL BE LARGE HAIL AND DAMAGING WINDS. WEAK SHEAR
INDICATE STORMS MAY BE PULSE-LIKE IN NATURE BUT SOME ORGANIZATION IS
LIKELY...SIMILAR TO TODAY`S ACTIVITY. ANOTHER ITEM TO NOTE IS THAT
STORM MOVEMENT SHOULD BE ROUGHLY PARALLEL TO THE FRONT. THIS MAY
LEAD TO A FLASH FLOODING THREAT IF STORMS TRAIN ALONG THE EAST/WEST
ORIENTED COLD FRONT. STORMS SHOULD EXIT THE REGION DURING THE
EVENING AS THE FRONT CONTINUES ITS SOUTHWARD PUSH.
FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT...BELOW NORMAL TEMPERATURES
AND DRY WEATHER CAN BE ANTICIPATED. IN FACT...WE WILL LIKELY OBSERVE
A FEW LOW TEMPERATURES IN THE UPPER 40S BOTH SATURDAY AND SUNDAY
NIGHTS. THIS IS SIMILAR TO THE COLD FRONT THAT PASSED THROUGH IN
RECENT DAYS. IN ADDITION TO COOLER WEATHER...VERY DRY AIR ADVECTS IN
FROM THE NORTHWEST. DRY AIR IS ALREADY IN PLACE ACCORDING TO
OBSERVATIONS ACROSS NORTHEAST COLORADO...WYOMING AND MONTANA. THIS
FURTHERS CONFIDENCE IN COOL TEMPERATURES WITH CLEAR SKIES OVERHEAD
AND LIGHT WINDS DUE TO A PASSING SURFACE HIGH PRESSURE.
A WARMING TREND BEGINS MONDAY AS AN UPPER LEVEL RIDGE BUILDS OVER
THE REGION. WITH THE RIDGE OF HIGH PRESSURE IN PLACE AND NO
APPRECIABLE SHORTWAVE TROUGHS ROUNDING THE RIDGE...WENT WITH A DRY
FORECAST. A FEW STORMS MAY SNEAK INTO EAST COLORADO TUESDAY EVENING
BUT MOST ACTIVITY SHOULD REMAIN CONFINED TO THE COLORADO FRONT RANGE.
WEDNESDAY AND BEYOND...GUIDANCE DISAGREEMENT AND UNCERTAINTY
REGARDING SHORTWAVE TROUGH POTENTIAL AND HIGH PRESSURE RIDGE
STRENGTH REDUCE FORECAST CONFIDENCE IN PRECIPITATION CHANCES.
MAINTAINED CR_INITIALIZATION POPS WHICH SEEMED REASONABLE GIVEN THIS
TIME OF YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1136 AM MDT FRI AUG 21 2015
VFR CONDITIONS EXPECTED FOR THE 18Z TAFS. SOUTH WINDS WILL
INCREASE THROUGH THE AFTERNOON THEN DECLINE SOME DURING THE
EVENING. SCATTERED STORMS WILL MOVE EAST ACROSS THE AREA AND BE
MOST LIKELY TO IMPACT KGLD RATHER THAN KMCK LATE THIS AFTERNOON
INTO THE EVENING. MINOR FOG MAY DEVELOP OVERNIGHT INTO EARLY
MORNING FOR BOTH SITES. AT THIS TIME KGLD LOOKS MORE FAVORABLE FOR
FOG THAN KMCK. SATURDAY WINDS WILL TURN TO THE WEST THEN NORTHWEST AHEAD
OF A COLD FRONT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1141 AM MDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 1003 AM MDT FRI AUG 21 2015
CURRENT FORECAST FOR THE AFTERNOON AND EVENING LOOKS ON TRACK
WITH THE LATEST OBSERVATIONS AND MODEL DATA. DID ADJUST THE
COVERAGE AND VALUE OF THE RAINFALL CHANCES A BIT GIVEN THE GOOD
AGREEMENT AMONG THE MODELS FOR THE STORM ACTIVITY THIS AFTERNOON.
EXPECT STORMS TO DEVELOP ALONG A SURFACE TROUGH/DRY LINE OVER THE
WESTERN PART OF THE AREA. THE STRONGEST LIFT WILL REMAIN TIED
TO THE NEARLY STATIONARY TROUGH THROUGH THE AFTERNOON...SO EXPECT
STORMS TO DEVELOP ALONG IT AND MOVE SLOWLY EAST. THE MAIN QUESTION
WILL BE HOW FAR EAST WILL THE STORMS GO BEFORE DISSIPATING SINCE
THE MAJORITY OF THE LIFT WILL REMAIN WITH THE SURFACE TROUGH.
CURRENTLY LOOKS LIKE THE MAJORITY OF THE STORMS WILL WEAKEN BY THE
TIME THEY REACH THE HIGHWAY 83 CORRIDOR...ALTHOUGH STORMS WHICH
MOVE OVER SOUTHWEST NEBRASKA MAY MAKE IT ALL THE WAY THROUGH RED
WILLOW COUNTY BEFORE DISSIPATING.
FOR THE EVENING AM NOT TOO CONFIDENT REGARDING STORMS EAST OF
HIGHWAY 25. AM THINKING ONCE THE SURFACE HEATING ENDS THE NOSE OF
THE LOW LEVEL JET WILL SERVE AS THE PRIMARY TRIGGER FOR
STORMS...WHICH WILL BE PRIMARILY WEST OF HIGHWAY 27. HOWEVER
SOUNDINGS INDICATE A FAIRLY DRY ENVIRONMENT DURING THE
EVENING WEST OF HIGHWAY 27...WHICH MAY HINDER STORM DEVELOPMENT
DESPITE THE INFLUENCE OF THE NOSE OF THE LOW LEVEL JET.
ASIDE FROM THE STORMS DID INCREASE THE WINDS DUE TO THE
STRENGTHENING LOW LEVEL JET IN THE AFTERNOON MIXING TO THE GROUND.
WEST OF THE SURFACE TROUGH THE WINDS WILL BE LIGHT DUE TO THE LOW.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 330 AM MDT FRI AUG 21 2015
FORECAST CONCERNS WILL BE THUNDERSTORM CHANCES INTO THE BEGINNING OF
THE WEEKEND AND HOW COOL TO MAKE IT SATURDAY NIGHT INTO SUNDAY
NIGHT. SATELLITE SHOWING AN AMPLIFIED/BLOCKY OVER THE PACIFIC. THIS
TRANSITIONS TO A BROAD TROUGH/WESTERLY ALOFT OVER MOST OF THE
COUNTRY. STRONG SYSTEM DIGGING INTO SOUTHWEST CANADA WITH SEVERAL
SHORTWAVE TROUGHS EMBEDDED IN THE WESTERLY FLOW.
AT JET LEVEL...MODELS DID WELL. AT MID LEVELS...THE GFS/CANADIAN AND
THE UKMET WERE DOING A LITTLE BETTER THAN THE ECMWF. THE SREF AND
ESPECIALLY THE NAM WERE NOT DOING WELL. THE GFS WAS DOING A LITTLE
BETTER THAN THE ECMWF WITH THE LOW LEVEL WIND FIELD. ALL MODELS
INITIALIZED WELL ON THE LOW LEVEL THERMAL FIELD
DIFFICULT AND UNCERTAIN PRECIPITATION FORECAST...ESPECIALLY
THROUGH THIS EVENING. CONFIDENCE IS BELOW AVERAGE FOR THE
PRECIPITATION FORECAST.
TODAY/TONIGHT...WILL HAVE TO KEEP AN EYE ON ANY LATE NIGHT/EARLY
MORNING DEVELOPMENT NEAR THE BOUNDARY JUST TO THE NORTH OF OUR
AREA. MODELS HAVE BEEN HINTING AT IT AND WILL CONTINUE TO MONITOR.
FOR YESTERDAYS THUNDERSTORMS...JUST ENOUGH MOISTURE ALONG A
BOUNDARY WITH A WEAK SHORTWAVE TROUGH WAS ABLE TO SPARK ISOLATED
THUNDERSTORMS OVER AND NEAR THE NORTHEAST PORTION OF THE AREA. NOT
TOO DIFFERENT A SETUP FOR TODAY FROM YESTERDAY. AGAIN WHAT MAKES
FORECAST UNCERTAIN IS THE MOISTURE AVAILABILITY...ESPECIALLY
ABOVE THE LOW LEVELS...WHERE DOES THE SURFACE TROUGH SETUP AND THE
WEAK/COMPLICATED MID LEVEL FORCING INVOLVED.
MODELS HAVE THE BOUNDARY PRETTY CLOSE BUT A LITTLE FURTHER WEST THAN
WHAT WAS SHOWN YESTERDAY. 700 MB SHORTWAVE EJECTS INTO THE PLAINS THIS
AFTERNOON AND IT LOOKS TO BE IN TWO PIECES. ONE PORTION GOES
ACROSS THE NORTH AND IS THE SLOWER OF THE TWO SHORTWAVE TROUGHS.
THE SECOND ONE GOES ACROSS TO OUR SOUTH AND BRUSHES THE SOUTHERN
PORTION OF THE AREA. THERE IS WEAK FORCING IN BETWEEN. ALSO THE
MODELS DIFFER ON HOW FAR EAST DURING THE DAY THEY MOVE THESE
SHORTWAVE TROUGHS.
CONVECTIVE ALLOWING MODELS ARE HAVING A DIFFICULT WITH ALL THIS. THE
ARW HAS LITTLE TO NOTHING. THE HRRR AND ESPECIALLY THE NMM DEVELOP
ROBUST CONVECTION OVER THE WESTERN PORTION OF THE AREA THIS
AFTERNOON CLOSE TO THE SURFACE TROUGH. THE 00Z NAM DID NOT INDICATE
ANYTHING BUT NOW THE 06Z NAM IS MATCHING UP WITH THE ABOVE TWO
MODELS. THE 00Z ECMWF EXPLODES CONVECTION OVER THE NORTHERN PORTION
OF THE AREA. ALL THIS TIME A RATHER STOUT EML LIES OVER THE AREA.
AFTER LOOKING AT THIS AND COLLABORATION...PULLED THE INITIATION A
LITTLE FURTHER WEST THAN BEFORE. THE PROBLEM THEN BECOMES HOW FAR
EAST TO TAKE THIS ACTIVITY. THE HRRR TAKES IT FURTHER EAST WHILE THE
REST OF THE OUTPUT THAT DID DEVELOP SOMETHING JUST KEEPS IT OVER
THE WEST AS IT EITHER DISSIPATES THE THUNDERSTORMS OR MOVES THEM
OF THE AREA TO THE NORTH OR SOUTH. SO DID LOWER POPS A LITTLE DUE
TO THIS.
IT DOES LOOK LIKE THE THUNDERSTORMS END BY 06Z. HOWEVER ELEVATED
STORMS/REDEVELOPMENT WILL NEED TO BE LOOKED AT AGAIN TO A LOW LEVEL
JET AND DECENT WARM AIR ADVECTION PATTERN ALOFT AHEAD OF ANOTHER
SHORTWAVE TROUGH. FOR THIS AFTERNOON AND EVENINGS CONVECTION...IF
STORMS DEVELOP...IT WILL BE POSSIBLE THAT THESE WILL BECOME SEVERE
DUE TO THE INSTABILITY AND LAPSE RATES INVOLVED. NO MATTER IF
STORMS DEVELOP OR NOT...BOUNDARY LAYER MOISTURE INCREASES AND AT
THE VERY LEAST A LOT OF STRATUS WILL DEVELOP WITH SOME PATCHY FOG
INVOLVED.
PRESSURE FALLS AND GRADIENT SUPPORT NEAR BREEZY OR BREEZY CONDITIONS.
GUIDANCE HAS BEEN RUNNING COOL ON MAXES HERE THE LAST FEW DAYS.
THE GFS/MAV HAS BEEN DOING THE BEST AND HAVE RAISED THE MAXES SOME.
SATURDAY/SATURDAY NIGHT...PATCHY FOG ENDS BY MID MORNING WITH THE
STRATUS LASTING A LITTLE LONGER. THERE ARE STILL DIFFERENCES IN
HOW FAST THE MODELS BRING IN THE COLD FRONT. THE NAM IS THE
SLOWEST FOLLOWED BY SREF. THE GFS/ECMWF/CANADIAN ARE THE FASTEST.
ROUGHLY IT LOOKS LIKE THE FRONT IS THROUGH THE NORTHWEST HALF OF
THE AREA BY LATE MORNING. THE FRONT THEN LOOKS TO MOVE ACROSS THE
REST OF THE AREA BY LATE AFTERNOON OR EARLY EVENING.
THE CHANCE OF THUNDERSTORMS WILL BE OVER THE SOUTHEAST PORTION OF
THE AREA IN ADVANCE OF THIS FRONT. CONTINUED THE LOW CHANCE POPS IN
THIS AREA. FRONT AND ASSOCIATED FORCING EXIT THE AREA EARLY IN
THE EVENING AND SO PRECIPITATION CUTS OFF RATHER FAST.
WINDS BEHIND THE FRONT COULD GET WINDY AND THE DAY SHIFT WILL NEED
TO LOOK AT RAISING THE WINDS EVEN MORE. DESPITE SIMILAR TIMING TO
YESTERDAYS OUTPUT...MODELS HAVE RAISED HIGH TEMPERATURES FOR THE
DAY. THE GFS...CANADIAN AND THE NAM ARE IN DECENT AGREEMENT ON
THIS. IT SEEMS THAT THE COLDER AIR DOES LAG SLIGHTLY BEHIND THE
FRONT. DID RAISE MAXES A LITTLE BUT THEY MAY NEED TO BE RAISED
EVEN MORE IN SOUTHERN LOCATIONS.
WINDS STAY UP ENOUGH TONIGHT THAT TEMPERATURES SHOULD NOT DROP
LIKE A ROCK. IF THE WINDS LET UP QUICKER...GOOD RADIATIONAL
CONDITIONS WOULD BE IN PLACE AND A LOWERING OF THE MINS WOULD BE
NEEDED.
SUNDAY/SUNDAY NIGHT...DRY PERIOD WITH POST FRONTAL COOL AIR MASS IN
PLACE. NEW GUIDANCE FOR TEMPERATURES VERY SIMILAR TO WHAT WAS IN
THERE FOR MAXES AND MADE ONLY SLIGHT ADJUSTMENTS. ONCE AGAIN FOR THE
MINS...IF WINDS END UP BEING LESS THAN CURRENTLY PREDICTED ADDITIONAL
COOLING WILL BE NEEDED.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 330 AM MDT FRI AUG 21 2015
THE EXTENDED PERIOD LOOKS TO BE MOSTLY DRY ALONG WITH NEAR TO ABOVE
NORMAL TEMPERATURES FOR THE AREA AS RIDGING INFLUENCES THE FORECAST.
ON MONDAY...AN UPPER LEVEL RIDGE CONTINUES TO BUILD INTO THE PLAINS
FOLLOWING THE SYSTEM PREDICTED TO IMPACT THE REGION THIS WEEKEND.
THE RIDGE AMPLIFIES AND MOVES EAST EARLY NEXT WEEK...WITH ITS AXIS
NEARING THE PLAINS ON WEDNESDAY. DRY CONDITIONS ARE EXPECTED DURING
THIS TIME FRAME.
MOISTURE RETURNS TO THE AREA WEDNESDAY AND THURSDAY AS A SHORTWAVE
MOVES ALONG THE PERSISTENT RIDGE. THIS DISTURBANCE LOOKS TO GENERATE
SHOWER AND THUNDERSTORM CHANCES WEDNESDAY NIGHT AND THURSDAY FOR
PORTIONS OF THE REGION.
AFTER SUNDAYS COOL DOWN...TEMPERATURES ARE EXPECTED TO QUICKLY
REBOUND IN THE EXTENDED PERIOD WITH HIGHS IN THE UPPER 80S TO LOW
90S AND LOWS IN THE UPPER 50S TO UPPER 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1136 AM MDT FRI AUG 21 2015
VFR CONDITIONS EXPECTED FOR THE 18Z TAFS. SOUTH WINDS WILL
INCREASE THROUGH THE AFTERNOON THEN DECLINE SOME DURING THE
EVENING. SCATTERED STORMS WILL MOVE EAST ACROSS THE AREA AND BE
MOST LIKELY TO IMPACT KGLD RATHER THAN KMCK LATE THIS AFTERNOON
INTO THE EVENING. MINOR FOG MAY DEVELOP OVERNIGHT INTO EARLY
MORNING FOR BOTH SITES. AT THIS TIME KGLD LOOKS MORE FAVORABLE FOR
FOG THAN KMCK. SATURDAY WINDS WILL TURN TO THE WEST THEN NORTHWEST AHEAD
OF A COLD FRONT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...JBH
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1019 AM MDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 1003 AM MDT FRI AUG 21 2015
CURRENT FORECAST FOR THE AFTERNOON AND EVENING LOOKS ON TRACK
WITH THE LATEST OBSERVATIONS AND MODEL DATA. DID ADJUST THE
COVERAGE AND VALUE OF THE RAINFALL CHANCES A BIT GIVEN THE GOOD
AGREEMENT AMONG THE MODELS FOR THE STORM ACTIVITY THIS AFTERNOON.
EXPECT STORMS TO DEVELOP ALONG A SURFACE TROUGH/DRY LINE OVER THE
WESTERN PART OF THE AREA. THE STRONGEST LIFT WILL REMAIN TIED
TO THE NEARLY STATIONARY TROUGH THROUGH THE AFTERNOON...SO EXPECT
STORMS TO DEVELOP ALONG IT AND MOVE SLOWLY EAST. THE MAIN QUESTION
WILL BE HOW FAR EAST WILL THE STORMS GO BEFORE DISSIPATING SINCE
THE MAJORITY OF THE LIFT WILL REMAIN WITH THE SURFACE TROUGH.
CURRENTLY LOOKS LIKE THE MAJORITY OF THE STORMS WILL WEAKEN BY THE
TIME THEY REACH THE HIGHWAY 83 CORRIDOR...ALTHOUGH STORMS WHICH
MOVE OVER SOUTHWEST NEBRASKA MAY MAKE IT ALL THE WAY THROUGH RED
WILLOW COUNTY BEFORE DISSIPATING.
FOR THE EVENING AM NOT TOO CONFIDENT REGARDING STORMS EAST OF
HIGHWAY 25. AM THINKING ONCE THE SURFACE HEATING ENDS THE NOSE OF
THE LOW LEVEL JET WILL SERVE AS THE PRIMARY TRIGGER FOR
STORMS...WHICH WILL BE PRIMARILY WEST OF HIGHWAY 27. HOWEVER
SOUNDINGS INDICATE A FAIRLY DRY ENVIRONMENT DURING THE
EVENING WEST OF HIGHWAY 27...WHICH MAY HINDER STORM DEVELOPMENT
DESPITE THE INFLUENCE OF THE NOSE OF THE LOW LEVEL JET.
ASIDE FROM THE STORMS DID INCREASE THE WINDS DUE TO THE
STRENGTHENING LOW LEVEL JET IN THE AFTERNOON MIXING TO THE GROUND.
WEST OF THE SURFACE TROUGH THE WINDS WILL BE LIGHT DUE TO THE LOW.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 330 AM MDT FRI AUG 21 2015
FORECAST CONCERNS WILL BE THUNDERSTORM CHANCES INTO THE BEGINNING OF
THE WEEKEND AND HOW COOL TO MAKE IT SATURDAY NIGHT INTO SUNDAY
NIGHT. SATELLITE SHOWING AN AMPLIFIED/BLOCKY OVER THE PACIFIC. THIS
TRANSITIONS TO A BROAD TROUGH/WESTERLY ALOFT OVER MOST OF THE
COUNTRY. STRONG SYSTEM DIGGING INTO SOUTHWEST CANADA WITH SEVERAL
SHORTWAVE TROUGHS EMBEDDED IN THE WESTERLY FLOW.
AT JET LEVEL...MODELS DID WELL. AT MID LEVELS...THE GFS/CANADIAN AND
THE UKMET WERE DOING A LITTLE BETTER THAN THE ECMWF. THE SREF AND
ESPECIALLY THE NAM WERE NOT DOING WELL. THE GFS WAS DOING A LITTLE
BETTER THAN THE ECMWF WITH THE LOW LEVEL WIND FIELD. ALL MODELS
INITIALIZED WELL ON THE LOW LEVEL THERMAL FIELD
DIFFICULT AND UNCERTAIN PRECIPITATION FORECAST...ESPECIALLY
THROUGH THIS EVENING. CONFIDENCE IS BELOW AVERAGE FOR THE
PRECIPITATION FORECAST.
TODAY/TONIGHT...WILL HAVE TO KEEP AN EYE ON ANY LATE NIGHT/EARLY
MORNING DEVELOPMENT NEAR THE BOUNDARY JUST TO THE NORTH OF OUR
AREA. MODELS HAVE BEEN HINTING AT IT AND WILL CONTINUE TO MONITOR.
FOR YESTERDAYS THUNDERSTORMS...JUST ENOUGH MOISTURE ALONG A
BOUNDARY WITH A WEAK SHORTWAVE TROUGH WAS ABLE TO SPARK ISOLATED
THUNDERSTORMS OVER AND NEAR THE NORTHEAST PORTION OF THE AREA. NOT
TOO DIFFERENT A SETUP FOR TODAY FROM YESTERDAY. AGAIN WHAT MAKES
FORECAST UNCERTAIN IS THE MOISTURE AVAILABILITY...ESPECIALLY
ABOVE THE LOW LEVELS...WHERE DOES THE SURFACE TROUGH SETUP AND THE
WEAK/COMPLICATED MID LEVEL FORCING INVOLVED.
MODELS HAVE THE BOUNDARY PRETTY CLOSE BUT A LITTLE FURTHER WEST THAN
WHAT WAS SHOWN YESTERDAY. 700 MB SHORTWAVE EJECTS INTO THE PLAINS THIS
AFTERNOON AND IT LOOKS TO BE IN TWO PIECES. ONE PORTION GOES
ACROSS THE NORTH AND IS THE SLOWER OF THE TWO SHORTWAVE TROUGHS.
THE SECOND ONE GOES ACROSS TO OUR SOUTH AND BRUSHES THE SOUTHERN
PORTION OF THE AREA. THERE IS WEAK FORCING IN BETWEEN. ALSO THE
MODELS DIFFER ON HOW FAR EAST DURING THE DAY THEY MOVE THESE
SHORTWAVE TROUGHS.
CONVECTIVE ALLOWING MODELS ARE HAVING A DIFFICULT WITH ALL THIS. THE
ARW HAS LITTLE TO NOTHING. THE HRRR AND ESPECIALLY THE NMM DEVELOP
ROBUST CONVECTION OVER THE WESTERN PORTION OF THE AREA THIS
AFTERNOON CLOSE TO THE SURFACE TROUGH. THE 00Z NAM DID NOT INDICATE
ANYTHING BUT NOW THE 06Z NAM IS MATCHING UP WITH THE ABOVE TWO
MODELS. THE 00Z ECMWF EXPLODES CONVECTION OVER THE NORTHERN PORTION
OF THE AREA. ALL THIS TIME A RATHER STOUT EML LIES OVER THE AREA.
AFTER LOOKING AT THIS AND COLLABORATION...PULLED THE INITIATION A
LITTLE FURTHER WEST THAN BEFORE. THE PROBLEM THEN BECOMES HOW FAR
EAST TO TAKE THIS ACTIVITY. THE HRRR TAKES IT FURTHER EAST WHILE THE
REST OF THE OUTPUT THAT DID DEVELOP SOMETHING JUST KEEPS IT OVER
THE WEST AS IT EITHER DISSIPATES THE THUNDERSTORMS OR MOVES THEM
OF THE AREA TO THE NORTH OR SOUTH. SO DID LOWER POPS A LITTLE DUE
TO THIS.
IT DOES LOOK LIKE THE THUNDERSTORMS END BY 06Z. HOWEVER ELEVATED
STORMS/REDEVELOPMENT WILL NEED TO BE LOOKED AT AGAIN TO A LOW LEVEL
JET AND DECENT WARM AIR ADVECTION PATTERN ALOFT AHEAD OF ANOTHER
SHORTWAVE TROUGH. FOR THIS AFTERNOON AND EVENINGS CONVECTION...IF
STORMS DEVELOP...IT WILL BE POSSIBLE THAT THESE WILL BECOME SEVERE
DUE TO THE INSTABILITY AND LAPSE RATES INVOLVED. NO MATTER IF
STORMS DEVELOP OR NOT...BOUNDARY LAYER MOISTURE INCREASES AND AT
THE VERY LEAST A LOT OF STRATUS WILL DEVELOP WITH SOME PATCHY FOG
INVOLVED.
PRESSURE FALLS AND GRADIENT SUPPORT NEAR BREEZY OR BREEZY CONDITIONS.
GUIDANCE HAS BEEN RUNNING COOL ON MAXES HERE THE LAST FEW DAYS.
THE GFS/MAV HAS BEEN DOING THE BEST AND HAVE RAISED THE MAXES SOME.
SATURDAY/SATURDAY NIGHT...PATCHY FOG ENDS BY MID MORNING WITH THE
STRATUS LASTING A LITTLE LONGER. THERE ARE STILL DIFFERENCES IN
HOW FAST THE MODELS BRING IN THE COLD FRONT. THE NAM IS THE
SLOWEST FOLLOWED BY SREF. THE GFS/ECMWF/CANADIAN ARE THE FASTEST.
ROUGHLY IT LOOKS LIKE THE FRONT IS THROUGH THE NORTHWEST HALF OF
THE AREA BY LATE MORNING. THE FRONT THEN LOOKS TO MOVE ACROSS THE
REST OF THE AREA BY LATE AFTERNOON OR EARLY EVENING.
THE CHANCE OF THUNDERSTORMS WILL BE OVER THE SOUTHEAST PORTION OF
THE AREA IN ADVANCE OF THIS FRONT. CONTINUED THE LOW CHANCE POPS IN
THIS AREA. FRONT AND ASSOCIATED FORCING EXIT THE AREA EARLY IN
THE EVENING AND SO PRECIPITATION CUTS OFF RATHER FAST.
WINDS BEHIND THE FRONT COULD GET WINDY AND THE DAY SHIFT WILL NEED
TO LOOK AT RAISING THE WINDS EVEN MORE. DESPITE SIMILAR TIMING TO
YESTERDAYS OUTPUT...MODELS HAVE RAISED HIGH TEMPERATURES FOR THE
DAY. THE GFS...CANADIAN AND THE NAM ARE IN DECENT AGREEMENT ON
THIS. IT SEEMS THAT THE COLDER AIR DOES LAG SLIGHTLY BEHIND THE
FRONT. DID RAISE MAXES A LITTLE BUT THEY MAY NEED TO BE RAISED
EVEN MORE IN SOUTHERN LOCATIONS.
WINDS STAY UP ENOUGH TONIGHT THAT TEMPERATURES SHOULD NOT DROP
LIKE A ROCK. IF THE WINDS LET UP QUICKER...GOOD RADIATIONAL
CONDITIONS WOULD BE IN PLACE AND A LOWERING OF THE MINS WOULD BE
NEEDED.
SUNDAY/SUNDAY NIGHT...DRY PERIOD WITH POST FRONTAL COOL AIR MASS IN
PLACE. NEW GUIDANCE FOR TEMPERATURES VERY SIMILAR TO WHAT WAS IN
THERE FOR MAXES AND MADE ONLY SLIGHT ADJUSTMENTS. ONCE AGAIN FOR THE
MINS...IF WINDS END UP BEING LESS THAN CURRENTLY PREDICTED ADDITIONAL
COOLING WILL BE NEEDED.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 330 AM MDT FRI AUG 21 2015
THE EXTENDED PERIOD LOOKS TO BE MOSTLY DRY ALONG WITH NEAR TO ABOVE
NORMAL TEMPERATURES FOR THE AREA AS RIDGING INFLUENCES THE FORECAST.
ON MONDAY...AN UPPER LEVEL RIDGE CONTINUES TO BUILD INTO THE PLAINS
FOLLOWING THE SYSTEM PREDICTED TO IMPACT THE REGION THIS WEEKEND.
THE RIDGE AMPLIFIES AND MOVES EAST EARLY NEXT WEEK...WITH ITS AXIS
NEARING THE PLAINS ON WEDNESDAY. DRY CONDITIONS ARE EXPECTED DURING
THIS TIME FRAME.
MOISTURE RETURNS TO THE AREA WEDNESDAY AND THURSDAY AS A SHORTWAVE
MOVES ALONG THE PERSISTENT RIDGE. THIS DISTURBANCE LOOKS TO GENERATE
SHOWER AND THUNDERSTORM CHANCES WEDNESDAY NIGHT AND THURSDAY FOR
PORTIONS OF THE REGION.
AFTER SUNDAYS COOL DOWN...TEMPERATURES ARE EXPECTED TO QUICKLY
REBOUND IN THE EXTENDED PERIOD WITH HIGHS IN THE UPPER 80S TO LOW
90S AND LOWS IN THE UPPER 50S TO UPPER 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 540 AM MDT FRI AUG 21 2015
AT THIS TIME VFR CONDITIONS ARE EXPECTED AT BOTH SITES. SOUTHERLY
WINDS WILL INCREASE THIS MORNING AND BECOME GUSTY. THESE GUSTY
WINDS WILL LAST WELL INTO THE NIGHT WITH SUSTAINED SPEEDS OF 14 TO
17 KNOTS WITH GUSTS 22 TO 25 KNOTS. THUNDERSTORMS ARE EXPECTED TO
DEVELOP THIS AFTERNOON AND EVENING BUT MODEL DIFFERENCES ON TIME
AND AREA OF INITIATION MAKE THINGS A LITTLE UNCERTAIN.
AT THIS TIME ONLY FEEL COMFORTABLE ENOUGH TO PUT IN A VCTS AT BOTH
SITES WITH KGLD STARTING AT 21Z AND KMCK AT 00Z. THUNDERSTORMS ARE
EXPECTED TO BE DONE BY 03Z. LATER IN THE NIGHT SOME FOG IS
EXPECTED VISIBILITIES STAYING ABOVE MVFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...JBH
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
545 AM MDT FRI AUG 21 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 330 AM MDT FRI AUG 21 2015
FORECAST CONCERNS WILL BE THUNDERSTORM CHANCES INTO THE BEGINNING OF
THE WEEKEND AND HOW COOL TO MAKE IT SATURDAY NIGHT INTO SUNDAY
NIGHT. SATELLITE SHOWING AN AMPLIFIED/BLOCKY OVER THE PACIFIC. THIS
TRANSITIONS TO A BROAD TROUGH/WESTERLY ALOFT OVER MOST OF THE
COUNTRY. STRONG SYSTEM DIGGING INTO SOUTHWEST CANADA WITH SEVERAL
SHORTWAVE TROUGHS EMBEDDED IN THE WESTERLY FLOW.
AT JET LEVEL...MODELS DID WELL. AT MID LEVELS...THE GFS/CANADIAN AND
THE UKMET WERE DOING A LITTLE BETTER THAN THE ECMWF. THE SREF AND
ESPECIALLY THE NAM WERE NOT DOING WELL. THE GFS WAS DOING A LITTLE
BETTER THAN THE ECMWF WITH THE LOW LEVEL WIND FIELD. ALL MODELS
INITIALIZED WELL ON THE LOW LEVEL THERMAL FIELD
DIFFICULT AND UNCERTAIN PRECIPITATION FORECAST...ESPECIALLY
THROUGH THIS EVENING. CONFIDENCE IS BELOW AVERAGE FOR THE
PRECIPITATION FORECAST.
TODAY/TONIGHT...WILL HAVE TO KEEP AN EYE ON ANY LATE NIGHT/EARLY
MORNING DEVELOPMENT NEAR THE BOUNDARY JUST TO THE NORTH OF OUR
AREA. MODELS HAVE BEEN HINTING AT IT AND WILL CONTINUE TO MONITOR.
FOR YESTERDAYS THUNDERSTORMS...JUST ENOUGH MOISTURE ALONG A
BOUNDARY WITH A WEAK SHORTWAVE TROUGH WAS ABLE TO SPARK ISOLATED
THUNDERSTORMS OVER AND NEAR THE NORTHEAST PORTION OF THE AREA. NOT
TOO DIFFERENT A SETUP FOR TODAY FROM YESTERDAY. AGAIN WHAT MAKES
FORECAST UNCERTAIN IS THE MOISTURE AVAILABILITY...ESPECIALLY
ABOVE THE LOW LEVELS...WHERE DOES THE SURFACE TROUGH SETUP AND THE
WEAK/COMPLICATED MID LEVEL FORCING INVOLVED.
MODELS HAVE THE BOUNDARY PRETTY CLOSE BUT A LITTLE FURTHER WEST THAN
WHAT WAS SHOWN YESTERDAY. 700 MB SHORTWAVE EJECTS INTO THE PLAINS THIS
AFTERNOON AND IT LOOKS TO BE IN TWO PIECES. ONE PORTION GOES
ACROSS THE NORTH AND IS THE SLOWER OF THE TWO SHORTWAVE TROUGHS.
THE SECOND ONE GOES ACROSS TO OUR SOUTH AND BRUSHES THE SOUTHERN
PORTION OF THE AREA. THERE IS WEAK FORCING IN BETWEEN. ALSO THE
MODELS DIFFER ON HOW FAR EAST DURING THE DAY THEY MOVE THESE
SHORTWAVE TROUGHS.
CONVECTIVE ALLOWING MODELS ARE HAVING A DIFFICULT WITH ALL THIS. THE
ARW HAS LITTLE TO NOTHING. THE HRRR AND ESPECIALLY THE NMM DEVELOP
ROBUST CONVECTION OVER THE WESTERN PORTION OF THE AREA THIS
AFTERNOON CLOSE TO THE SURFACE TROUGH. THE 00Z NAM DID NOT INDICATE
ANYTHING BUT NOW THE 06Z NAM IS MATCHING UP WITH THE ABOVE TWO
MODELS. THE 00Z ECMWF EXPLODES CONVECTION OVER THE NORTHERN PORTION
OF THE AREA. ALL THIS TIME A RATHER STOUT EML LIES OVER THE AREA.
AFTER LOOKING AT THIS AND COLLABORATION...PULLED THE INITIATION A
LITTLE FURTHER WEST THAN BEFORE. THE PROBLEM THEN BECOMES HOW FAR
EAST TO TAKE THIS ACTIVITY. THE HRRR TAKES IT FURTHER EAST WHILE THE
REST OF THE OUTPUT THAT DID DEVELOP SOMETHING JUST KEEPS IT OVER
THE WEST AS IT EITHER DISSIPATES THE THUNDERSTORMS OR MOVES THEM
OF THE AREA TO THE NORTH OR SOUTH. SO DID LOWER POPS A LITTLE DUE
TO THIS.
IT DOES LOOK LIKE THE THUNDERSTORMS END BY 06Z. HOWEVER ELEVATED
STORMS/REDEVELOPMENT WILL NEED TO BE LOOKED AT AGAIN TO A LOW LEVEL
JET AND DECENT WARM AIR ADVECTION PATTERN ALOFT AHEAD OF ANOTHER
SHORTWAVE TROUGH. FOR THIS AFTERNOON AND EVENINGS CONVECTION...IF
STORMS DEVELOP...IT WILL BE POSSIBLE THAT THESE WILL BECOME SEVERE
DUE TO THE INSTABILITY AND LAPSE RATES INVOLVED. NO MATTER IF
STORMS DEVELOP OR NOT...BOUNDARY LAYER MOISTURE INCREASES AND AT
THE VERY LEAST A LOT OF STRATUS WILL DEVELOP WITH SOME PATCHY FOG
INVOLVED.
PRESSURE FALLS AND GRADIENT SUPPORT NEAR BREEZY OR BREEZY CONDITIONS.
GUIDANCE HAS BEEN RUNNING COOL ON MAXES HERE THE LAST FEW DAYS.
THE GFS/MAV HAS BEEN DOING THE BEST AND HAVE RAISED THE MAXES SOME.
SATURDAY/SATURDAY NIGHT...PATCHY FOG ENDS BY MID MORNING WITH THE
STRATUS LASTING A LITTLE LONGER. THERE ARE STILL DIFFERENCES IN
HOW FAST THE MODELS BRING IN THE COLD FRONT. THE NAM IS THE
SLOWEST FOLLOWED BY SREF. THE GFS/ECMWF/CANADIAN ARE THE FASTEST.
ROUGHLY IT LOOKS LIKE THE FRONT IS THROUGH THE NORTHWEST HALF OF
THE AREA BY LATE MORNING. THE FRONT THEN LOOKS TO MOVE ACROSS THE
REST OF THE AREA BY LATE AFTERNOON OR EARLY EVENING.
THE CHANCE OF THUNDERSTORMS WILL BE OVER THE SOUTHEAST PORTION OF
THE AREA IN ADVANCE OF THIS FRONT. CONTINUED THE LOW CHANCE POPS IN
THIS AREA. FRONT AND ASSOCIATED FORCING EXIT THE AREA EARLY IN
THE EVENING AND SO PRECIPITATION CUTS OFF RATHER FAST.
WINDS BEHIND THE FRONT COULD GET WINDY AND THE DAY SHIFT WILL NEED
TO LOOK AT RAISING THE WINDS EVEN MORE. DESPITE SIMILAR TIMING TO
YESTERDAYS OUTPUT...MODELS HAVE RAISED HIGH TEMPERATURES FOR THE
DAY. THE GFS...CANADIAN AND THE NAM ARE IN DECENT AGREEMENT ON
THIS. IT SEEMS THAT THE COLDER AIR DOES LAG SLIGHTLY BEHIND THE
FRONT. DID RAISE MAXES A LITTLE BUT THEY MAY NEED TO BE RAISED
EVEN MORE IN SOUTHERN LOCATIONS.
WINDS STAY UP ENOUGH TONIGHT THAT TEMPERATURES SHOULD NOT DROP
LIKE A ROCK. IF THE WINDS LET UP QUICKER...GOOD RADIATIONAL
CONDITIONS WOULD BE IN PLACE AND A LOWERING OF THE MINS WOULD BE
NEEDED.
SUNDAY/SUNDAY NIGHT...DRY PERIOD WITH POST FRONTAL COOL AIR MASS IN
PLACE. NEW GUIDANCE FOR TEMPERATURES VERY SIMILAR TO WHAT WAS IN
THERE FOR MAXES AND MADE ONLY SLIGHT ADJUSTMENTS. ONCE AGAIN FOR THE
MINS...IF WINDS END UP BEING LESS THAN CURRENTLY PREDICTED ADDITIONAL
COOLING WILL BE NEEDED.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 330 AM MDT FRI AUG 21 2015
THE EXTENDED PERIOD LOOKS TO BE MOSTLY DRY ALONG WITH NEAR TO ABOVE
NORMAL TEMPERATURES FOR THE AREA AS RIDGING INFLUENCES THE FORECAST.
ON MONDAY...AN UPPER LEVEL RIDGE CONTINUES TO BUILD INTO THE PLAINS
FOLLOWING THE SYSTEM PREDICTED TO IMPACT THE REGION THIS WEEKEND.
THE RIDGE AMPLIFIES AND MOVES EAST EARLY NEXT WEEK...WITH ITS AXIS
NEARING THE PLAINS ON WEDNESDAY. DRY CONDITIONS ARE EXPECTED DURING
THIS TIME FRAME.
MOISTURE RETURNS TO THE AREA WEDNESDAY AND THURSDAY AS A SHORTWAVE
MOVES ALONG THE PERSISTENT RIDGE. THIS DISTURBANCE LOOKS TO GENERATE
SHOWER AND THUNDERSTORM CHANCES WEDNESDAY NIGHT AND THURSDAY FOR
PORTIONS OF THE REGION.
AFTER SUNDAYS COOL DOWN...TEMPERATURES ARE EXPECTED TO QUICKLY
REBOUND IN THE EXTENDED PERIOD WITH HIGHS IN THE UPPER 80S TO LOW
90S AND LOWS IN THE UPPER 50S TO UPPER 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 540 AM MDT FRI AUG 21 2015
AT THIS TIME VFR CONDITIONS ARE EXPECTED AT BOTH SITES. SOUTHERLY
WINDS WILL INCREASE THIS MORNING AND BECOME GUSTY. THESE GUSTY
WINDS WILL LAST WELL INTO THE NIGHT WITH SUSTAINED SPEEDS OF 14 TO
17 KNOTS WITH GUSTS 22 TO 25 KNOTS. THUNDERSTORMS ARE EXPECTED TO
DEVELOP THIS AFTERNOON AND EVENING BUT MODEL DIFFERENCES ON TIME
AND AREA OF INITIATION MAKE THINGS A LITTLE UNCERTAIN.
AT THIS TIME ONLY FEEL COMFORTABLE ENOUGH TO PUT IN A VCTS AT BOTH
SITES WITH KGLD STARTING AT 21Z AND KMCK AT 00Z. THUNDERSTORMS ARE
EXPECTED TO BE DONE BY 03Z. LATER IN THE NIGHT SOME FOG IS
EXPECTED VISIBILITIES STAYING ABOVE MVFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...JBH
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
352 AM MDT FRI AUG 21 2015
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 330 AM MDT FRI AUG 21 2015
FORECAST CONCERNS WILL BE THUNDERSTORM CHANCES INTO THE BEGINNING OF
THE WEEKEND AND HOW COOL TO MAKE IT SATURDAY NIGHT INTO SUNDAY
NIGHT. SATELLITE SHOWING AN AMPLIFIED/BLOCKY OVER THE PACIFIC. THIS
TRANSITIONS TO A BROAD TROUGH/WESTERLY ALOFT OVER MOST OF THE
COUNTRY. STRONG SYSTEM DIGGING INTO SOUTHWEST CANADA WITH SEVERAL
SHORTWAVE TROUGHS EMBEDDED IN THE WESTERLY FLOW.
AT JET LEVEL...MODELS DID WELL. AT MID LEVELS...THE GFS/CANADIAN AND
THE UKMET WERE DOING A LITTLE BETTER THAN THE ECMWF. THE SREF AND
ESPECIALLY THE NAM WERE NOT DOING WELL. THE GFS WAS DOING A LITTLE
BETTER THAN THE ECMWF WITH THE LOW LEVEL WIND FIELD. ALL MODELS
INITIALIZED WELL ON THE LOW LEVEL THERMAL FIELD
DIFFICULT AND UNCERTAIN PRECIPITATION FORECAST...ESPECIALLY
THROUGH THIS EVENING. CONFIDENCE IS BELOW AVERAGE FOR THE
PRECIPITATION FORECAST.
TODAY/TONIGHT...WILL HAVE TO KEEP AN EYE ON ANY LATE NIGHT/EARLY
MORNING DEVELOPMENT NEAR THE BOUNDARY JUST TO THE NORTH OF OUR
AREA. MODELS HAVE BEEN HINTING AT IT AND WILL CONTINUE TO MONITOR.
FOR YESTERDAYS THUNDERSTORMS...JUST ENOUGH MOISTURE ALONG A
BOUNDARY WITH A WEAK SHORTWAVE TROUGH WAS ABLE TO SPARK ISOLATED
THUNDERSTORMS OVER AND NEAR THE NORTHEAST PORTION OF THE AREA. NOT
TOO DIFFERENT A SETUP FOR TODAY FROM YESTERDAY. AGAIN WHAT MAKES
FORECAST UNCERTAIN IS THE MOISTURE AVAILABILITY...ESPECIALLY
ABOVE THE LOW LEVELS...WHERE DOES THE SURFACE TROUGH SETUP AND THE
WEAK/COMPLICATED MID LEVEL FORCING INVOLVED.
MODELS HAVE THE BOUNDARY PRETTY CLOSE BUT A LITTLE FURTHER WEST THAN
WHAT WAS SHOWN YESTERDAY. 700 MB SHORTWAVE EJECTS INTO THE PLAINS THIS
AFTERNOON AND IT LOOKS TO BE IN TWO PIECES. ONE PORTION GOES
ACROSS THE NORTH AND IS THE SLOWER OF THE TWO SHORTWAVE TROUGHS.
THE SECOND ONE GOES ACROSS TO OUR SOUTH AND BRUSHES THE SOUTHERN
PORTION OF THE AREA. THERE IS WEAK FORCING IN BETWEEN. ALSO THE
MODELS DIFFER ON HOW FAR EAST DURING THE DAY THEY MOVE THESE
SHORTWAVE TROUGHS.
CONVECTIVE ALLOWING MODELS ARE HAVING A DIFFICULT WITH ALL THIS. THE
ARW HAS LITTLE TO NOTHING. THE HRRR AND ESPECIALLY THE NMM DEVELOP
ROBUST CONVECTION OVER THE WESTERN PORTION OF THE AREA THIS
AFTERNOON CLOSE TO THE SURFACE TROUGH. THE 00Z NAM DID NOT INDICATE
ANYTHING BUT NOW THE 06Z NAM IS MATCHING UP WITH THE ABOVE TWO
MODELS. THE 00Z ECMWF EXPLODES CONVECTION OVER THE NORTHERN PORTION
OF THE AREA. ALL THIS TIME A RATHER STOUT EML LIES OVER THE AREA.
AFTER LOOKING AT THIS AND COLLABORATION...PULLED THE INITIATION A
LITTLE FURTHER WEST THAN BEFORE. THE PROBLEM THEN BECOMES HOW FAR
EAST TO TAKE THIS ACTIVITY. THE HRRR TAKES IT FURTHER EAST WHILE THE
REST OF THE OUTPUT THAT DID DEVELOP SOMETHING JUST KEEPS IT OVER
THE WEST AS IT EITHER DISSIPATES THE THUNDERSTORMS OR MOVES THEM
OF THE AREA TO THE NORTH OR SOUTH. SO DID LOWER POPS A LITTLE DUE
TO THIS.
IT DOES LOOK LIKE THE THUNDERSTORMS END BY 06Z. HOWEVER ELEVATED
STORMS/REDEVELOPMENT WILL NEED TO BE LOOKED AT AGAIN TO A LOW LEVEL
JET AND DECENT WARM AIR ADVECTION PATTERN ALOFT AHEAD OF ANOTHER
SHORTWAVE TROUGH. FOR THIS AFTERNOON AND EVENINGS CONVECTION...IF
STORMS DEVELOP...IT WILL BE POSSIBLE THAT THESE WILL BECOME SEVERE
DUE TO THE INSTABILITY AND LAPSE RATES INVOLVED. NO MATTER IF
STORMS DEVELOP OR NOT...BOUNDARY LAYER MOISTURE INCREASES AND AT
THE VERY LEAST A LOT OF STRATUS WILL DEVELOP WITH SOME PATCHY FOG
INVOLVED.
PRESSURE FALLS AND GRADIENT SUPPORT NEAR BREEZY OR BREEZY CONDITIONS.
GUIDANCE HAS BEEN RUNNING COOL ON MAXES HERE THE LAST FEW DAYS.
THE GFS/MAV HAS BEEN DOING THE BEST AND HAVE RAISED THE MAXES SOME.
SATURDAY/SATURDAY NIGHT...PATCHY FOG ENDS BY MID MORNING WITH THE
STRATUS LASTING A LITTLE LONGER. THERE ARE STILL DIFFERENCES IN
HOW FAST THE MODELS BRING IN THE COLD FRONT. THE NAM IS THE
SLOWEST FOLLOWED BY SREF. THE GFS/ECMWF/CANADIAN ARE THE FASTEST.
ROUGHLY IT LOOKS LIKE THE FRONT IS THROUGH THE NORTHWEST HALF OF
THE AREA BY LATE MORNING. THE FRONT THEN LOOKS TO MOVE ACROSS THE
REST OF THE AREA BY LATE AFTERNOON OR EARLY EVENING.
THE CHANCE OF THUNDERSTORMS WILL BE OVER THE SOUTHEAST PORTION OF
THE AREA IN ADVANCE OF THIS FRONT. CONTINUED THE LOW CHANCE POPS IN
THIS AREA. FRONT AND ASSOCIATED FORCING EXIT THE AREA EARLY IN
THE EVENING AND SO PRECIPITATION CUTS OFF RATHER FAST.
WINDS BEHIND THE FRONT COULD GET WINDY AND THE DAY SHIFT WILL NEED
TO LOOK AT RAISING THE WINDS EVEN MORE. DESPITE SIMILAR TIMING TO
YESTERDAYS OUTPUT...MODELS HAVE RAISED HIGH TEMPERATURES FOR THE
DAY. THE GFS...CANADIAN AND THE NAM ARE IN DECENT AGREEMENT ON
THIS. IT SEEMS THAT THE COLDER AIR DOES LAG SLIGHTLY BEHIND THE
FRONT. DID RAISE MAXES A LITTLE BUT THEY MAY NEED TO BE RAISED
EVEN MORE IN SOUTHERN LOCATIONS.
WINDS STAY UP ENOUGH TONIGHT THAT TEMPERATURES SHOULD NOT DROP
LIKE A ROCK. IF THE WINDS LET UP QUICKER...GOOD RADIATIONAL
CONDITIONS WOULD BE IN PLACE AND A LOWERING OF THE MINS WOULD BE
NEEDED.
SUNDAY/SUNDAY NIGHT...DRY PERIOD WITH POST FRONTAL COOL AIR MASS IN
PLACE. NEW GUIDANCE FOR TEMPERATURES VERY SIMILAR TO WHAT WAS IN
THERE FOR MAXES AND MADE ONLY SLIGHT ADJUSTMENTS. ONCE AGAIN FOR THE
MINS...IF WINDS END UP BEING LESS THAN CURRENTLY PREDICTED ADDITIONAL
COOLING WILL BE NEEDED.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 330 AM MDT FRI AUG 21 2015
THE EXTENDED PERIOD LOOKS TO BE MOSTLY DRY ALONG WITH NEAR TO ABOVE
NORMAL TEMPERATURES FOR THE AREA AS RIDGING INFLUENCES THE FORECAST.
ON MONDAY...AN UPPER LEVEL RIDGE CONTINUES TO BUILD INTO THE PLAINS
FOLLOWING THE SYSTEM PREDICTED TO IMPACT THE REGION THIS WEEKEND.
THE RIDGE AMPLIFIES AND MOVES EAST EARLY NEXT WEEK...WITH ITS AXIS
NEARING THE PLAINS ON WEDNESDAY. DRY CONDITIONS ARE EXPECTED DURING
THIS TIME FRAME.
MOISTURE RETURNS TO THE AREA WEDNESDAY AND THURSDAY AS A SHORTWAVE
MOVES ALONG THE PERSISTENT RIDGE. THIS DISTURBANCE LOOKS TO GENERATE
SHOWER AND THUNDERSTORM CHANCES WEDNESDAY NIGHT AND THURSDAY FOR
PORTIONS OF THE REGION.
AFTER SUNDAYS COOL DOWN...TEMPERATURES ARE EXPECTED TO QUICKLY
REBOUND IN THE EXTENDED PERIOD WITH HIGHS IN THE UPPER 80S TO LOW
90S AND LOWS IN THE UPPER 50S TO UPPER 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1000 PM MDT THU AUG 20 2015
FOR KGLD AND KMCK VFR CONDITIONS EXPECTED. SOUTH WINDS 7-11KTS AT
TAF ISSUANCE EXPECTED TO CONTINUE THROUGH 14Z OR SO BEFORE
INCREASING TO 12KT THRESHOLD AROUND 15Z. GUSTS TO 25KTS OR SO
EXPECTED FROM 17Z THROUGH SUNSET. AFTER SUNSET SUSTAINED SOUTH
WINDS AROUND 13KTS EXPECTED. WILL HAVE TO WATCH A SFC TROUGH/WIND
SHIFT LINE THAT IS FORECAST TO EXTEND FROM NEAR KIML TO KGLD/KITR
AROUND 00Z. CONVERGENCE ALONG THIS BOUNDARY AND AN UNSTABLE
AIRMASS SUGGEST AT LEAST ISOLATED THUNDERSTORMS POSSIBLE. GIVEN
THE LOW THREAT OF DIRECTLY IMPACTING THE TERMINAL (KGLD) WILL
LEAVE OUT OF THE FORECAST FOR NOW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...JBH
AVIATION...99
AREA FORECAST DISCUSSION
NWS JACKSON KY
1110 PM EDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 1110 PM EDT SAT AUG 22 2015
WATER VAPOR SAT AND MOST MODELS ARE CONTINUING TO SHOW MID LEVEL
WAVE PROGRESSING EAST INTO THE REGION. THAT SAID RIGHT NOW THINK
THE GFS HAS THE BEST HANDLE ON THE SYNOPTICS THIS EVENING...THE
NAM SEEMS A BIT TOO ROBUST WITH MOISTURE OVERALL. NOW RADAR HAS
SHOWN A FEW RETURNS TO THE SW AND INTO PORTIONS OF CENTRAL
KY...BUT MUCH OF THIS IS AT MOST SPRINKLES BASED ON THE HIGH
BASES/MOSTLY ABOVE 10 KFT. THEREFORE JUST ISSUED A GNOW TO COVER
THIS GIVEN THE FACT THAT THIS ACTIVITY IS LIKELY NOT MEASURING.
THE HRRR HAS CONTINUED TO WEAKEN ANY OF THE SHOWERS ACROSS CENTRAL
KY AND MIDDLE TN...SO DID NOT ADJUST THE POPS UP MUCH GIVEN THIS
TREND. MAINLY MADE SOME ADJUSTMENTS TO TEMP/DEWS/WINDS WITH LATEST
OBS.
UPDATE ISSUED AT 727 PM EDT SAT AUG 22 2015
SYNOPTICALLY WE CONTINUE TO HAVE HIGH PRESSURE CENTERED OFF TO THE
NE NEAR THE UPPER MID ATLANTIC REGION...BUT STILL KEEPING CONTROL
OF THE OVERALL SENSIBLE WEATHER HERE IN EASTERN KY. MODELS AND WV
IMAGERY INDICATE LEAD MID LEVEL WAVE SLOWLY MOVING EAST ACROSS THE
MIDDLE MISSISSIPPI RIVER VALLEY. THIS HAS SPARKED OFF SHOWERS AND
THUNDERSTORMS IN MIDDLE TN...WEST TN...WESTERN KY THAT ARE SLOWLY
MOVING NORTH AND EAST...HOWEVER THEY ARE LOSING STEAM AS THEY MOVE
NE WITH GENERALLY DRIER AIR IN PLACE AND HIGH PRESSURE NOSING
SOUTH. OVERALL THE CAMS SEEM TO KEEP THIS TREND THIS EVENING AS
WELL...ALSO THEY DO HAVE SOME SIGNAL OVERNIGHT/EARLY MORNING
SUNDAY AND WE ALREADY HAVE SLIGHT POPS IN THE SOUTH AND SOUTHEAST
TO MATCH. THEREFORE THINK POPS THIS EVENING/OVERNIGHT ARE IN GOOD
SHAPE IN REGARDS TO PREVIOUS FORECAST AND LATEST TRENDS. JUST SOME
MINOR UPDATES TO IN TEMPS/DEWS/WINDS WITH LATEST OBS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 340 PM EDT SAT AUG 22 2015
THIS AFTERNOON...A SHORTWAVE RIDGE WAS WORKING ACROSS THE REGION
DOWNSTREAM OF A SHORTWAVE NEARING THE MID MS AND LOWER OH VALLEYS.
ANOTHER MORE POTENT SHORTWAVE MEANWHILE IS WORKING FROM THE
NORTHERN ROCKIES INTO THE DAKOTAS. AT THE SFC...A LOW PRESSURE
SYSTEM PRECEDING THE MORE POTENT SHORTWAVE WAVE CENTERED OVER THE
NE SD AND NW MN AREA. THE LEAD SHORTWAVE WILL BRING INCREASING
MID AND HIGH MOISTURE LEADING TO AN INCREASE IN MID AND HIGH
CLOUDS THROUGH THE EVENING AND INTO THE OVERNIGHT. LOW LEVEL
MOISTURE WILL ALSO INCREASE A BIT AS WELL ESPECIALLY ACROSS THE
SOUTH. AS THE SHORTWAVE PASSES LATE TONIGHT A SHOWER OR TWO MAY
CREEP NORTH INTO THE SOUTHERN TIER OF COUNTIES FROM WAYNE
NORTHEAST TOWARD LETCHER.
MUCH OF SUNDAY FEATURE SOME HEIGHT RISES AND MOSTLY DRY WEATHER
IN BETWEEN THE DEPARTING INITIAL LEAD SHORTWAVE AND THE NEXT
APPROACHING SHORTWAVE AND THE COLD FRONT AS THE UPPER LEVEL LOW
AND SFC LOW PRESSURE CENTER MOVE INTO ONTARIO. THE SYSTEM WILL
GENERALLY BE RATHER MOISTURE STARVED AND INSTABILITY WILL BE
LIMITED DUE TO THE NON OPTIMAL TIMING OF THE COLD FRONT WHILE THE
BEST FORCING WILL ALSO PASS NORTH OF THE AREA. ANY CONVECTION
FROM LATE SUNDAY INTO SUNDAY NIGHT WILL LIKELY BE MAINLY ISOLATED
TO SCATTERED SHOWERS ALTHOUGH A FEW ISOLATED RUMBLES CANNOT BE
COMPLETELY RULED OUT. QPF FROM THIS SYSTEM SHOULD ALSO BE LIGHT
AND MANY LOCATIONS SHOULD REMAIN DRY THROUGH THE ENTIRE EVENT.
TEMPERATURES WILL MODERATE A FEW DEGREES FROM LAST NIGHTS
OVERNIGHT LOWS ALTHOUGH LESS CLOUD COVER IN THE NORTH AND
NORTHEAST SHOULD LEAD TO LOWER MIN T THERE...REACHING THE UPPER
50S FOR VALLEY LOCATIONS. AHEAD OF THE FRONT...WITH A WARMER START
AND WARM AIR ADVECTION AHEAD OF THE FRONT...TEMPERATURES SHOULD BE
A COUPLE DEGREES WARMER THAN TODAY ON AVERAGE. HOWEVER...HIGHS ON
SUNDAY SHOULD STILL BE NEAR NORMAL FOR THE LATTER PART OF AUGUST.
CLOUDS AND SOME PRECIP IN THE AREA AS THE FRONT BEGINS TO WORK
ACROSS EAST KY WILL LEAD TO AN EVEN MILDER NIGHT ON SUNDAY NIGHT.
HOWEVER...A RETURN TO BELOW NORMAL TEMPERATURES IS EXPECTED DURING
THE LONG TERM PERIOD.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 246 PM EDT SAT AUG 22 2015
SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION AS A COLD FRONT
DEPARTS TO OUR EAST ON MONDAY. A FEW SHOWERS WILL REMAIN IN THE
FORECAST MONDAY MORNING...BUT THE REST OF THE PERIOD WILL BE DRY
AS THE HIGH BECOMES DOMINANT. A VERY FALL LIKE PATTERN CAN BE
EXPECTED WITH COMFORTABLE DEWPOINTS AND TEMPERATURES RUNNING 5 TO
10 DEGREES BELOW NORMAL THROUGH MOST OF THE PERIOD...WITH THE
BIGGEST DEPARTURES OCCURRING AT NIGHT AS THE DRY AIRMASS ALLOWS
TEMPS TO FALL INTO THE 50S. SOME MODIFICATION WILL OCCUR IN THE
AIRMASS BY SATURDAY WITH TEMPS WARMING BACK TO NEAR NORMAL LEVELS
FOR THE END OF AUGUST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 742 PM EDT SAT AUG 22 2015
HIGH PRESSURE REMAINS IN CONTROL AND WILL KEEP THE TAF PERIOD VFR.
THERE ARE SOME MID AND HIGH LEVEL CLOUDS STREAMING ACROSS THE
REGION THIS AFTERNOON/EVENING...HOWEVER THESE HAVE BEEN ALL VFR.
THE OTHER FORECAST ISSUE WILL BE ANY POTENTIAL FOR SHOWERS AS LEAD
MID LEVEL WAVE APPROACHES FROM THE WEST. OVERALL TRENDS ON RADAR
THIS EVENING HAVE MUCH OF THE PRECIP FALLING APART AS IT MOVES
NORTH AND EAST. THE HIGH PRESSURE AND GENERALLY DRY AIR LIKELY
PLAYING IN OUR FAVOR. HOWEVER SINCE CONVECTIVE MODELS STILL HINT
AT SOME SHOWER POTENTIAL IN THE SOUTH HAVE KEPT THE VCSH MENTION
FOR LOZ/SME. INCREASES IN MOISTURE ARE PROBABLE IN RETURN FLOW
REGIME...SO KEPT CLOSE TO PREVIOUS TAF WITH INCREASING CLOUDS
OVERTIME. WINDS THROUGH THE TAF PERIOD WILL REMAIN LIGHT...BUT
WILL BEGIN TO SHIFT TO MORE OF A SOUTHERLY DIRECTION.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...JP
LONG TERM...ABE
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
936 PM EDT SAT AUG 22 2015
...FORECAST UPDATE...
ISSUED AT 930 PM EDT SAT AUG 22 2015
HAVE SOME LIGHT RETURNS ON RADAR ACROSS OUR SOUTHERN ZONES...BUT
LATEST KY MESONET DATA SHOWING NONE OF THIS IS REACHING THE GROUND.
DEWPOINTS HAVE RISEN HOWEVER DOWN THERE...SO SEEING SOME LOWER-LEVEL
MOISTENING. AS LEAD SHORTWAVE CROSSES THE REGION TONIGHT CANNOT RULE
OUT A FEW SPOTS GETTING A HUNDREDTH OR TWO OF PRECIP. ALSO WITH THE
INCREASE IN DEWPOINTS AND LIGHT WINDS WE MAY SEE SOME PATCHY FOG BY
DAYBREAK. UPDATED PRODUCTS OUT SHORTLY.
.SHORT TERM (NOW THROUGH SUNDAY NIGHT)...
ISSUED AT 215 PM EDT SAT AUG 22 2015
AS OF MID AFTERNOON...WATER VAPOR IMAGERY WITH 500MB HEIGHTS SHOWED
TWO FEATURES OF INTEREST IN THE SHORT TERM PERIOD. FIRST...A WEAK
SHORTWAVE WAS SKIRTING ACROSS MISSOURI/ARKANSAS/WESTERN TN WHILE A
MORE SIGNIFICANT SHORTWAVE TROUGH WAS ADVANCING THROUGH THE NORTHERN
PLAINS. AT THE SURFACE...HIGH PRESSURE CENTERED OVER BUFFALO NY WAS
PROVIDING THE LOWER OHIO VALLEY WITH COOL AND COMFORTABLE WEATHER
FOR MID AUGUST.
THIS EVENING...THE SOUTHERN SHORTWAVE TROUGH WILL SLOWLY APPROACH
MIDDLE TENNNESSEE AND WEAKEN BUT CURRENT RADAR TRENDS COMBINED WITH
VARIOUS HI-RES MODELS SUGGEST THAT LIGHT PRECIPITATION COULD SLIDE
ACROSS FAR SOUTHERN KENTUCKY. THE PRECIPITATION WILL BE WORKING INTO
A LESS FAVORABLE AIR MASS AND TIME OF DAY...BUT COULDN`T RULE OUT
SOME SPRINKLES OR LIGHT RAIN SHOWERS FOR A COUPLE HOURS ALONG THE
KY/TN BORDER. OTHERWISE...PLAN ON INCREASING CLOUDS FROM THE
SOUTHWEST FOR THE AREA AND PLEASANT EVENING TEMPERATURES. MILDER
LOWS TONIGHT THANKS TO MORE CLOUD COVER...RANGING FROM LOW TO MID
60S.
TRENDS IN THE MODEL DATA SUGGEST THAT THE NEXT SYSTEM SLATED TO COME
THROUGH SUNDAY WILL BE A FEW HOURS SLOWER THAN PREVIOUSLY THOUGHT.
AS THE UPPER LEVEL TROUGH PIVOTS THROUGH THE GREAT LAKES REGION...A
SURFACE LOW AND ITS COLD FRONT WILL APPROACH DURING THE DAY. THE
FRONT WILL LIKELY REACH SOUTHERN INDIANA AND WESTERN KENTUCKY BY MID
AFTERNOON...THEN CROSS THE AREA DURING THE LATE AFTERNOON TO LATE
EVENING HOURS.
A NARROW AXIS OF MODERATELY UNSTABLE AIR /1000 TO 1500 J/KG SBCAPE/
IS ANTICIPATED THANKS TO SOME /LIMITED/ MOISTURE RETURN. AN
INCREASING 300 MB JET AND THE UPPER TROUGH SWINGING THROUGH TO OUR
NORTH WILL AID IN THE DEVELOPMENT OF 25 TO 35 KTS OF 0-6 KM BULK
SHEAR. QUESTIONS REMAIN ON HOW MUCH INSTABILITY WILL BE REALIZED DUE
TO 1) MOSTLY CLOUDY SKIES AHEAD OF THE FRONT FROM ONGOING AND
MORNING CONVECTION TO OUR NORTH/WEST...2) MODEL DEWPOINTS OVERDONE
AND...3) SLOWER TIMING THAT LIMITS PEAK HEATING POTENTIAL.
SO...CONFIDENCE IS LOW TO MEDIUM FOR SEEING STRONGER STORMS. THE
HIGHEST CHANCE WOULD BE ACROSS SOUTHERN INDIANA AND NORTHERN
KENTUCKY...AND MAIN THREAT WOULD BE A STRONG DAMAGING WIND GUST. FOR
TIMING PURPOSES...HIGHEST CHANCES LOOKS TO BE FROM MID AFTERNOON TO
MID EVENING AS A BROKEN LINE OF CONVECTION MOVES WEST TO EAST.
OTHERWISE...PLAN ON A WARMER AND NOTICEABLY MUGGIER DAY WITH HIGHS
NEARING SEASONAL NORMALS /MID TO UPPER 80S/. WINDS WILL BECOME
SOUTHERLY...APPROACHING 10 TO 15 MPH AT TIMES DURING THE AFTERNOON.
THE FRONT MAKES A CLEAN SWEEP THROUGH INDIANA AND KENTUCKY SUNDAY
EVENING/NIGHT...USHERING IN A REINFORCING SHOT OF COOLER AND DRIER
AIR. MONDAY MORNING TEMPERATURES ARE LIKELY TO BE IN THE MID 50S
/WEST/ TO LOW AND MID 60S /EAST/.
.LONG TERM (MONDAY THROUGH SATURDAY)...
ISSUED AT 220 PM EDT SAT AUG 22 2015
STRONG RIDGING OVER THE WESTERN CONUS AND A STRONG UPPER LOW OVER
THE NORTHERN GREAT LAKES/SOUTHERN CANADA WILL DOMINATE THE UPPER
LEVEL PATTERN FOR MUCH OF THE UPCOMING WEEK. THIS WILL RESULT IN
DRY, UNSEASONABLY COOL CONDITIONS. EXPECT HIGH TEMPS TO RANGE
THROUGH THE MID 70S TO AROUND 80 MON-THU WITH LOWS IN THE 50S. A
FEW LOCATIONS MAY EVEN TOUCH THE UPPER 40S THU MORNING.
BY FRIDAY, THE UPPER LOW WILL MOVE OUT TO THE ATLANTIC ALLOWING
WARMER AIR TO CREEP BACK INTO THE OHIO VALLEY. WE`LL SEE A GRADUAL
WARMING TREND THROUGH THE 80S FRIDAY AND THROUGH THE WEEKEND. STILL
NO SIGNIFICANT CHANCES FOR RAIN OVER THE NEXT SEVERAL DAYS.
&&
.AVIATION (00Z TAF UPDATE)...
ISSUED AT 730 PM EDT SAT AUG 22 2015
HAVE A COUPLE OF DISTURBANCES FORECAST TO AFFECT OUR WEATHER THIS
PERIOD. THE FIRST IS BRINGING SOME SPRINKLES TO KBWG THIS HOUR...AS
WELL AS MID/HIGH CLOUDS. THE LATEST RAP SHOWS MORE CLOUD COVER
THROUGH THE NIGHT DOWN THERE...AND BASED ON CURRENT UPSTREAM TRENDS
WILL LEAN MORE TOWARD A PESSIMISTIC FORECAST AND GO MVFR A LITTLE
AFTER MIDNIGHT. OTHER SITES SHOULD REMAIN VFR AS THERE IS QUITE A
BIT OF DRY AIR TO OVERCOME NORTH AND EAST OF KBWG.
LATER IN THE PERIOD...A COLD FRONT WILL CROSS THE REGION. A FEW
SHOWERS/STORMS ARE FORECAST ALONG THIS FRONT AND HAVE ENOUGH
CONFIDENCE TO PUT IN A PROB30 GROUP AT KSDF FOR NOW. THINK THE OTHER
SITES WILL HOLD OFF TILL JUST AFTER THEIR TAF PERIODS.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........RJS
SHORT TERM.....ZBT
LONG TERM......AMS
AVIATION.......RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
731 PM EDT SAT AUG 22 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM (NOW THROUGH SUNDAY NIGHT)...
ISSUED AT 215 PM EDT SAT AUG 22 2015
AS OF MID AFTERNOON...WATER VAPOR IMAGERY WITH 500MB HEIGHTS SHOWED
TWO FEATURES OF INTEREST IN THE SHORT TERM PERIOD. FIRST...A WEAK
SHORTWAVE WAS SKIRTING ACROSS MISSOURI/ARKANSAS/WESTERN TN WHILE A
MORE SIGNIFICANT SHORTWAVE TROUGH WAS ADVANCING THROUGH THE NORTHERN
PLAINS. AT THE SURFACE...HIGH PRESSURE CENTERED OVER BUFFALO NY WAS
PROVIDING THE LOWER OHIO VALLEY WITH COOL AND COMFORTABLE WEATHER
FOR MID AUGUST.
THIS EVENING...THE SOUTHERN SHORTWAVE TROUGH WILL SLOWLY APPROACH
MIDDLE TENNNESSEE AND WEAKEN BUT CURRENT RADAR TRENDS COMBINED WITH
VARIOUS HI-RES MODELS SUGGEST THAT LIGHT PRECIPITATION COULD SLIDE
ACROSS FAR SOUTHERN KENTUCKY. THE PRECIPITATION WILL BE WORKING INTO
A LESS FAVORABLE AIR MASS AND TIME OF DAY...BUT COULDN`T RULE OUT
SOME SPRINKLES OR LIGHT RAIN SHOWERS FOR A COUPLE HOURS ALONG THE
KY/TN BORDER. OTHERWISE...PLAN ON INCREASING CLOUDS FROM THE
SOUTHWEST FOR THE AREA AND PLEASANT EVENING TEMPERATURES. MILDER
LOWS TONIGHT THANKS TO MORE CLOUD COVER...RANGING FROM LOW TO MID
60S.
TRENDS IN THE MODEL DATA SUGGEST THAT THE NEXT SYSTEM SLATED TO COME
THROUGH SUNDAY WILL BE A FEW HOURS SLOWER THAN PREVIOUSLY THOUGHT.
AS THE UPPER LEVEL TROUGH PIVOTS THROUGH THE GREAT LAKES REGION...A
SURFACE LOW AND ITS COLD FRONT WILL APPROACH DURING THE DAY. THE
FRONT WILL LIKELY REACH SOUTHERN INDIANA AND WESTERN KENTUCKY BY MID
AFTERNOON...THEN CROSS THE AREA DURING THE LATE AFTERNOON TO LATE
EVENING HOURS.
A NARROW AXIS OF MODERATELY UNSTABLE AIR /1000 TO 1500 J/KG SBCAPE/
IS ANTICIPATED THANKS TO SOME /LIMITED/ MOISTURE RETURN. AN
INCREASING 300 MB JET AND THE UPPER TROUGH SWINGING THROUGH TO OUR
NORTH WILL AID IN THE DEVELOPMENT OF 25 TO 35 KTS OF 0-6 KM BULK
SHEAR. QUESTIONS REMAIN ON HOW MUCH INSTABILITY WILL BE REALIZED DUE
TO 1) MOSTLY CLOUDY SKIES AHEAD OF THE FRONT FROM ONGOING AND
MORNING CONVECTION TO OUR NORTH/WEST...2) MODEL DEWPOINTS OVERDONE
AND...3) SLOWER TIMING THAT LIMITS PEAK HEATING POTENTIAL.
SO...CONFIDENCE IS LOW TO MEDIUM FOR SEEING STRONGER STORMS. THE
HIGHEST CHANCE WOULD BE ACROSS SOUTHERN INDIANA AND NORTHERN
KENTUCKY...AND MAIN THREAT WOULD BE A STRONG DAMAGING WIND GUST. FOR
TIMING PURPOSES...HIGHEST CHANCES LOOKS TO BE FROM MID AFTERNOON TO
MID EVENING AS A BROKEN LINE OF CONVECTION MOVES WEST TO EAST.
OTHERWISE...PLAN ON A WARMER AND NOTICEABLY MUGGIER DAY WITH HIGHS
NEARING SEASONAL NORMALS /MID TO UPPER 80S/. WINDS WILL BECOME
SOUTHERLY...APPROACHING 10 TO 15 MPH AT TIMES DURING THE AFTERNOON.
THE FRONT MAKES A CLEAN SWEEP THROUGH INDIANA AND KENTUCKY SUNDAY
EVENING/NIGHT...USHERING IN A REINFORCING SHOT OF COOLER AND DRIER
AIR. MONDAY MORNING TEMPERATURES ARE LIKELY TO BE IN THE MID 50S
/WEST/ TO LOW AND MID 60S /EAST/.
.LONG TERM (MONDAY THROUGH SATURDAY)...
ISSUED AT 220 PM EDT SAT AUG 22 2015
STRONG RIDGING OVER THE WESTERN CONUS AND A STRONG UPPER LOW OVER
THE NORTHERN GREAT LAKES/SOUTHERN CANADA WILL DOMINATE THE UPPER
LEVEL PATTERN FOR MUCH OF THE UPCOMING WEEK. THIS WILL RESULT IN
DRY, UNSEASONABLY COOL CONDITIONS. EXPECT HIGH TEMPS TO RANGE
THROUGH THE MID 70S TO AROUND 80 MON-THU WITH LOWS IN THE 50S. A
FEW LOCATIONS MAY EVEN TOUCH THE UPPER 40S THU MORNING.
BY FRIDAY, THE UPPER LOW WILL MOVE OUT TO THE ATLANTIC ALLOWING
WARMER AIR TO CREEP BACK INTO THE OHIO VALLEY. WE`LL SEE A GRADUAL
WARMING TREND THROUGH THE 80S FRIDAY AND THROUGH THE WEEKEND. STILL
NO SIGNIFICANT CHANCES FOR RAIN OVER THE NEXT SEVERAL DAYS.
&&
.AVIATION (00Z TAF UPDATE)...
ISSUED AT 730 PM EDT SAT AUG 22 2015
HAVE A COUPLE OF DISTURBANCES FORECAST TO AFFECT OUR WEATHER THIS
PERIOD. THE FIRST IS BRINGING SOME SPRINKLES TO KBWG THIS HOUR...AS
WELL AS MID/HIGH CLOUDS. THE LATEST RAP SHOWS MORE CLOUD COVER
THROUGH THE NIGHT DOWN THERE...AND BASED ON CURRENT UPSTREAM TRENDS
WILL LEAN MORE TOWARD A PESSIMISTIC FORECAST AND GO MVFR A LITTLE
AFTER MIDNIGHT. OTHER SITES SHOULD REMAIN VFR AS THERE IS QUITE A
BIT OF DRY AIR TO OVERCOME NORTH AND EAST OF KBWG.
LATER IN THE PERIOD...A COLD FRONT WILL CROSS THE REGION. A FEW
SHOWERS/STORMS ARE FORECAST ALONG THIS FRONT AND HAVE ENOUGH
CONFIDENCE TO PUT IN A PROB30 GROUP AT KSDF FOR NOW. THINK THE OTHER
SITES WILL HOLD OFF TILL JUST AFTER THEIR TAF PERIODS.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........ZBT
LONG TERM.........AMS
AVIATION..........RJS
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1051 PM CDT SAT AUG 22 2015
.UPDATE...UPDATED GFS AND LATEST HRRR CONFIRMS THAT THE SHORT
WAVE ENERGY HAS MOVED A BIT FURTHER SOUTH, SO REMOVED MENTION OF
SHOWERS INLAND FROM THE COASTAL MARSHES.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 819 PM CDT SAT AUG 22 2015/
UPDATE...IR IMAGERY SHOWING MID AND UPPER LEVEL CLOUD COVER WHICH
IS CONFIRMED BY THE EVENING SOUNDING. SOME JET ENERGY IS AVAILABLE
ACROSS THE NORTHERN ZONES LATE TNITE...ALSO SEEN ON THE IR IMAGERY
UPSTREAM OVER NORTH TEXAS. SHORT WAVE ENERGY REMAINS AVAILABLE
ACROSS THE SOUTHERN ZONES. CANNOT RULE OUT ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY TONIGHT SO ADDED MINIMAL POPS. TEMPS ON TRACK.
SWEENEY
PREV DISCUSSION... /ISSUED 652 PM CDT SAT AUG 22 2015/
AVIATION...
STORMS ARE MOVING TO THE NORTHEAST ACROSS SOUTH-CENTRAL LOUISIANA
THIS EVENING. LFT AND ARA WILL STILL HAVE A SLIGHT CHANCE FOR A
SHOWER/TSTMS OTHERWISE LCH/AEX AND BPT LOOK TO REMAIN CLEAR OF
STORMS THROUGH SUNRISE. STORM ENDING BEFORE MIDNIGHT.
K. KUYPER
PREV DISCUSSION... /ISSUED 312 PM CDT SAT AUG 22 2015/
DISCUSSION...
WEAK SFC HIGH OVER THE NE GULF PROVIDING FOR A LIGHT SE FLOW
ACROSS THE REGION. RADAR SHOWING SCT/NUM SHRA/TSRA ACROSS SE TX/C
AND S LA THIS AFTERNOON AS INSTABILITY REMAINS HIGH AND FAVORABLE
LOW LEVEL MOISTURE. WITH A BIT MORE COVERAGE THAN EXPECTED...BUMPED
UP POPS TO 60% FOR MAJORITY OF INLAND AREA NORTH OF THE INTRACOASTAL
WATERWAY THIS AFTERNOON. TEMPS ALL OVER THE PLACE FROM THE RAIN
COOLED 70S TO LOWER 90S ACROSS C LA WHERE THE RAIN HASN`T REACHED
YET. CONVECTION EXPECTED TO DIMINISH THIS EVENING AND THE
OVERNIGHT HOURS.
BY SUN...DRIER AIR ALOFT EXPECTED TO MINIMALIZE PRECIP CHANCES TO
20% DURING THE AFTERNOON. HIGHS IN THE MID 90S EXPECTED. WITH
HIGHER THAN NORMAL DEWPTS IN THE UPPER 70S DURING THE MORNING...TO
MID 70S DURING THE AFTERNOON...HEAT INDEX VALUES LIKELY TO RANGE
100-105 FOR MOST OF THE DAYLIGHT HOURS SUN. GENERALLY THE SAME
EXPECTED FOR MON AS WELL. HOWEVER...A DEEPENING LONGWAVE TROF OVER
THE C AND E U.S. EXPECTED TO ALLOW A COOL FRONT TO MOVE S ACROSS
THE REGION MON NIGHT AND TUE. PRECIP CHANCES EXPECTED TO INCREASE
BY MON AFTERNOON ACROSS OUR REGION...AND ALONG THE FROPA MON
NIGHT/TUE MORNING.
POST FRONTAL WX CONTINUES TO LOOK DRY FOR WED INTO THE REMAINDER
OF THE WEEK. OVERNIGHT TEMPS LIKELY TO BE IN THE 60S FOR MOST OF
THE REGION (EXCEPT COASTAL PARISHES/COUNTIES) FOR NEXT THU & FRI
MORNINGS. HIGHS STILL IN THE LOWER 90S...BUT WITH MUCH LOWER
DEWPTS IN THE 50S/60S...IT WILL BE MORE BEARABLE OUTSIDE.
DML
MARINE...
A LIGHT ONSHORE FLOW WILL PERSIST TONIGHT...BECOMING VARIABLE
SUNDAY AND MONDAY AS THE PRESSURE GRADIENT REMAINS WEAK. CHANCES
OF SHOWERS AND THUNDERSTORMS EXPECTED TO INCREASE AGAIN BY LATE
MONDAY INTO TUESDAY AS A COOL FRONT MOVES THROUGH THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 76 96 76 95 / 10 20 10 30
LCH 76 93 77 95 / 10 30 10 30
LFT 75 95 76 95 / 10 30 10 40
BPT 79 92 77 95 / 10 30 10 30
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
PUBLIC...11
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1238 PM CDT FRI AUG 21 2015
.DISCUSSION...
FOR THE 21/18Z TAF ISSUANCE.
&&
.AVIATION...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE TO SPREAD NORTH
DURING THE AFTERNOON HOURS. MAIN ACTIVITY HAS MOVED NORTH OF
KBPT...SO WILL JUST MENTION VCSH THERE. WILL HAVE PREVAILING
SHOWERS WITH VCTS FOR KLCH/KLFT/KARA THROUGH MID AFTERNOON
21/20Z...WITH ACTIVITY BEGINNING AT KAEX AROUND 21/19Z. UPPER
LEVEL DISTURBANCE WILL MOVE OFF TO THE NORTH LATE THIS
AFTERNOON...AND WITH LOSS OF DAYTIME HEATING...MOST OF THE
ACTIVITY WILL DISSIPATE BY 22/01Z...WITH VFR CONDITIONS THEN
EXPECTED FOR THE NIGHT...WITH EXCEPTION OF KAEX...WHERE SOME MVFR
PATCHY FOG MAY OCCUR NEAR DAYBREAK.
RUA
&&
.PREV DISCUSSION... /ISSUED 954 AM CDT FRI AUG 21 2015/
DISCUSSION...
NUM SHRA/TSRA BEGINNING TO MOVE ASHORE SE TX/SW LA IN ASSOCIATION
WITH THE NEXT UPPER LEVEL IMPULSE MOVING NE ACROSS THE TX COAST
THIS MORNING. THUS...HAD TO BUMP UP POPS AND QPF SIGNIFICANTLY
THIS MORNING...CLOSE TO HRRR GUIDANCE WHICH HAS A GOOD HANDLE ON
THIS SITUATION. ALSO INCLUDED HEAVY RAINFALL POSSIBLE AS THESE
WILL BE SOMEWHAT SLOWER MOVING. WITH THE INCREASED CLOUD COVER...AGREE
WITH HRRR AND LOWERED TEMPS ACROSS SE TX/SW LA. OTHERWISE...BUMPED
UP WINDS A BIT TO 10-15 KTS ACROSS THE COASTAL WATERS THIS MORNING
AS THIS SYSTEM MOVES ACROSS THE REGION. THATS ABOUT IT. UPDATES
ALREADY OUT.
DML
PREV DISCUSSION... /ISSUED 716 AM CDT FRI AUG 21 2015/
DISCUSSION...
FOR THE 12Z TAF PACKAGE.
AVIATION...
QUIETER NIGHT AND MORNING VERSUS THE PREVIOUS COUPLE OF
DAYS...THOUGH CONVECTIVE ACTIVITY HAS BEEN ON THE INCREASE OVER THE
COASTAL WATERS FOR THE PAST COUPLE OF HRS...ESPECIALLY OFF THE SE
TX/SW LA COASTS. LATEST HIGH RESOLUTION MODEL DATA DEPICTS THE
WELL DEFINED SHORTWAVE OVER THE MIDDLE TX COAST...AND ITS
ASSOCIATED CONVECTION...LIFTING NE THROUGH THE AREA LATER THIS
MORNING INTO THE AFTERNOON. VCTS WAS INSERTED AT EACH SITE BASED
ON THIS THINKING. RECENT PLUNGE IN VSBY AT KAEX IS EXPECTED TO BE
SHORT LIVED...PERHAPS AN HR OR SO. WILL CONTINUE TO MONITOR FOR A
POSSIBLE AMD. VFR EXPECTED TO PREVAIL OUTSIDE OF CONVECTION...AND
BY THIS EVENING AS ACTIVITY LIFTS NE OF THE AREA.
13
PREV DISCUSSION... /ISSUED 452 AM CDT FRI AUG 21 2015/
SYNOPSIS...
A NEARLY STATIONARY W-E ORIENTED SFC FRONT EXTENDS FM NE TX ACRS
NRN LA INTO CNTL MS. THE FRONT HAS BECOME A LITTLE MORE DIFFUSE
THE PAST SEVERAL HOURS...AS DEWPOINTS ALONG AND SOUTH OF THE
FRONTAL ZONE ARE IN THE LOWER TO MIDDLE 70S WITH COOLER AND DRIER
AIR LOCATED WELL BEHIND THE BOUNDARY ACRS NRN/CNTL ARK AND FAR N
MS.
THE LATEST WV IMAGERY AND UA ANALYSIS SHOWS MOISTURE ALOFT BEING
FUNNELED OVER THE REGION ON SWLY FLOW BETWEEN A TROF/WEAKNESS
OVER THE SRN PLAINS AND AN UPR RIDGE ACRS THE GULF OF MEXICO.
A LITTLE LESS CONVECTIVE ACTIVITY SO FAR TODAY THAN THE PAST
COUPLE OF MORNINGS...ALTHOUGH REGIONAL RADAR MOSAIC SHOWS SCT
SHOWERS AND A FEW TSTMS DEVELOPING OFF THE UPR TX COAST AND OVER
GALVESTON BAY WITH MORE ISOLATED ACTIVITY OVER OUR COASTAL WATERS
ZONES. FURTHER INLAND...A BAND OF LT TO MDT RAIN WAS LOCATED NEAR
THE FRONTAL BOUNDARY...FM JUST NORTH OF THE LAKES REGION OF SE TX
INTO PORTIONS OF WRN LA.
DISCUSSION...
THE FRONT WILL GRADUALLY WEAKEN AS IT LIFTS BACK NORTH LATER
TODAY. HOWEVER...ABUNDANT MOISTURE REMAINS OVER THE AREA AND WITH
THE LINGERING DISTURBANCE OR WEAKNESS ALOFT...EXPECT SCT
CONVECTION TO AGAIN DEVELOP TODAY. THIS ACTIVITY IS EXPECTED TO BE
MORE DIURNALLY DRIVEN...WITH THE SEABREEZE BOUNDARY AND THE
DISSIPATING FRONT FOCUSING CONVECTIVE DEVELOPMENT AS DAYTIME
HEATING GETS UNDERWAY. PRECIP WATER VALUES WILL REMAIN NEAR 2
INCHES...AND THIS SHOULD AGAIN ALLOW TSTMS TO BE EFFICIENT
RAINFALL PRODUCERS WITH HIGH RAIN RATES AT TIMES. CLOUDY SKIES ON
THURSDAY HELPED TO KEEP TEMPERATURES IN THE 80S...WITH SOME
LOCATIONS ONLY REACHING THE LOWER 80S. WHILE THIS MAY BE THE CASE
AGAIN TODAY...THINK CLOUD AND CONVECTIVE COVERAGE WILL BE A LITTLE
LESS AND OCCASIONAL PEEKS OF SUN SHOULD ALLOW TEMPERATURES TO RISE
TO NEAR 90 IN THE AFTN.
MEANWHILE...THE WEAKNESS ALOFT WILL MORE OR LESS LINGER OVER THE
REGION THROUGH THE WEEKEND EVEN AS THE HIGH OVER THE ERN GULF
BEGINS TO BUILD WEST. THERE WILL STILL BE A DAILY CHC FOR SHOWERS
OR STORMS SATURDAY AND SUNDAY BUT COVERAGE WILL BE LOWER AS
SLIGHTLY DRIER AIR BEGINS TO WORK INTO THE REGION. WITH LESS
CONVECTION AND CLOUDS...AFTN TEMPERATURES WILL BEGIN A WARMING
TREND.
BY EARLY NEXT WEEK...THE HIGH WILL RETROGRADE FURTHER WEST AS A
SHORTWAVE TROF DIGS OVER THE ERN STATES...WITH THE SYSTEM
GRADUALLY AMPLIFYING OVER THE CONUS. THIS WILL LEAD TO A DEEPENING
NLY FLOW THAT WILL PUSH A SFC FRONT INTO THE AREA BY TUESDAY. RAIN
CHCS WILL BUMP BACK UP IN ADVANCE OF THE FRONT MONDAY INTO
TUESDAY. GLOBAL MODELS ARE IN GENERAL AGREEMENT REGARDING THE
DEVELOPMENT OF THIS AMPLIFIED SYSTEM AND ASSOCIATED SFC
FROPA...AND KEEPING THE AREA UNDER A NLY FLOW ALOFT THROUGH THE
LATTER PART OF THE WEEK. SHOULD THIS SCENARIO PAN OUT...DRIER MORE
COMFORTABLE CONDITIONS CAN BE EXPECTED FROM WEDNESDAY THROUGH
FRIDAY WITH SLIGHTLY BELOW NORMAL LOWS IN THE UPPER 60S TO LOWER
70S AND HIGHS NEAR NORMAL IN THE LOWER 90S.
24
MARINE...
A LT TO OCCASIONALLY MDT ONSHORE FLOW AND LOW SEAS WILL PERSIST
THROUGH EARLY NEXT WEEK AS HIGH PRES CONTINUES TO RIDGE OVER THE
GULF. A LINGERING DISTURBANCE OVER THE REGION WILL ALLOW FOR SCT
SHOWERS AND TSTMS TODAY...BUT RAIN CHCS WILL DECREASE OVER THE
WEEKEND AS HIGH PRES BUILDS ALOFT. A FRONT WILL MOVE SOUTH INTO
THE AREA BY LATE MONDAY INTO TUESDAY...BRINGING ANOTHER CHC FOR
SHOWERS OR TSTMS. AT THIS TIME...MODEL GUIDANCE SHOWS THIS FRONT
MOVING SOUTH OVER THE COASTAL WATERS ZONES...WITH OFFSHORE FLOW
AND DRIER WEATHER POSSIBLE FOR THE MIDDLE AND LATTER PART OF NEXT
WEEK.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 92 74 94 75 / 70 20 30 10
LCH 85 77 90 77 / 60 20 30 10
LFT 87 76 91 76 / 70 20 30 10
BPT 84 77 90 77 / 80 20 30 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
954 AM CDT FRI AUG 21 2015
.DISCUSSION...
NUM SHRA/TSRA BEGINNING TO MOVE ASHORE SE TX/SW LA IN ASSOCIATION
WITH THE NEXT UPPER LEVEL IMPULSE MOVING NE ACROSS THE TX COAST
THIS MORNING. THUS...HAD TO BUMP UP POPS AND QPF SIGNIFICANTLY
THIS MORNING...CLOSE TO HRRR GUIDANCE WHICH HAS A GOOD HANDLE ON
THIS SITUATION. ALSO INCLUDED HEAVY RAINFALL POSSIBLE AS THESE
WILL BE SOMEWHAT SLOWER MOVING. WITH THE INCREASED CLOUD COVER...AGREE
WITH HRRR AND LOWERED TEMPS ACROSS SE TX/SW LA. OTHERWISE...BUMPED
UP WINDS A BIT TO 10-15 KTS ACROSS THE COASTAL WATERS THIS MORNING
AS THIS SYSTEM MOVES ACROSS THE REGION. THATS ABOUT IT. UPDATES
ALREADY OUT.
DML
&&
.PREV DISCUSSION... /ISSUED 716 AM CDT FRI AUG 21 2015/
DISCUSSION...
FOR THE 12Z TAF PACKAGE.
AVIATION...
QUIETER NIGHT AND MORNING VERSUS THE PREVIOUS COUPLE OF
DAYS...THOUGH CONVECTIVE ACTIVITY HAS BEEN ON THE INCREASE OVER THE
COASTAL WATERS FOR THE PAST COUPLE OF HRS...ESPECIALLY OFF THE SE
TX/SW LA COASTS. LATEST HIGH RESOLUTION MODEL DATA DEPICTS THE
WELL DEFINED SHORTWAVE OVER THE MIDDLE TX COAST...AND ITS
ASSOCIATED CONVECTION...LIFTING NE THROUGH THE AREA LATER THIS
MORNING INTO THE AFTERNOON. VCTS WAS INSERTED AT EACH SITE BASED
ON THIS THINKING. RECENT PLUNGE IN VSBY AT KAEX IS EXPECTED TO BE
SHORT LIVED...PERHAPS AN HR OR SO. WILL CONTINUE TO MONITOR FOR A
POSSIBLE AMD. VFR EXPECTED TO PREVAIL OUTSIDE OF CONVECTION...AND
BY THIS EVENING AS ACTIVITY LIFTS NE OF THE AREA.
13
PREV DISCUSSION... /ISSUED 452 AM CDT FRI AUG 21 2015/
SYNOPSIS...
A NEARLY STATIONARY W-E ORIENTED SFC FRONT EXTENDS FM NE TX ACRS
NRN LA INTO CNTL MS. THE FRONT HAS BECOME A LITTLE MORE DIFFUSE
THE PAST SEVERAL HOURS...AS DEWPOINTS ALONG AND SOUTH OF THE
FRONTAL ZONE ARE IN THE LOWER TO MIDDLE 70S WITH COOLER AND DRIER
AIR LOCATED WELL BEHIND THE BOUNDARY ACRS NRN/CNTL ARK AND FAR N
MS.
THE LATEST WV IMAGERY AND UA ANALYSIS SHOWS MOISTURE ALOFT BEING
FUNNELED OVER THE REGION ON SWLY FLOW BETWEEN A TROF/WEAKNESS
OVER THE SRN PLAINS AND AN UPR RIDGE ACRS THE GULF OF MEXICO.
A LITTLE LESS CONVECTIVE ACTIVITY SO FAR TODAY THAN THE PAST
COUPLE OF MORNINGS...ALTHOUGH REGIONAL RADAR MOSAIC SHOWS SCT
SHOWERS AND A FEW TSTMS DEVELOPING OFF THE UPR TX COAST AND OVER
GALVESTON BAY WITH MORE ISOLATED ACTIVITY OVER OUR COASTAL WATERS
ZONES. FURTHER INLAND...A BAND OF LT TO MDT RAIN WAS LOCATED NEAR
THE FRONTAL BOUNDARY...FM JUST NORTH OF THE LAKES REGION OF SE TX
INTO PORTIONS OF WRN LA.
DISCUSSION...
THE FRONT WILL GRADUALLY WEAKEN AS IT LIFTS BACK NORTH LATER
TODAY. HOWEVER...ABUNDANT MOISTURE REMAINS OVER THE AREA AND WITH
THE LINGERING DISTURBANCE OR WEAKNESS ALOFT...EXPECT SCT
CONVECTION TO AGAIN DEVELOP TODAY. THIS ACTIVITY IS EXPECTED TO BE
MORE DIURNALLY DRIVEN...WITH THE SEABREEZE BOUNDARY AND THE
DISSIPATING FRONT FOCUSING CONVECTIVE DEVELOPMENT AS DAYTIME
HEATING GETS UNDERWAY. PRECIP WATER VALUES WILL REMAIN NEAR 2
INCHES...AND THIS SHOULD AGAIN ALLOW TSTMS TO BE EFFICIENT
RAINFALL PRODUCERS WITH HIGH RAIN RATES AT TIMES. CLOUDY SKIES ON
THURSDAY HELPED TO KEEP TEMPERATURES IN THE 80S...WITH SOME
LOCATIONS ONLY REACHING THE LOWER 80S. WHILE THIS MAY BE THE CASE
AGAIN TODAY...THINK CLOUD AND CONVECTIVE COVERAGE WILL BE A LITTLE
LESS AND OCCASIONAL PEEKS OF SUN SHOULD ALLOW TEMPERATURES TO RISE
TO NEAR 90 IN THE AFTN.
MEANWHILE...THE WEAKNESS ALOFT WILL MORE OR LESS LINGER OVER THE
REGION THROUGH THE WEEKEND EVEN AS THE HIGH OVER THE ERN GULF
BEGINS TO BUILD WEST. THERE WILL STILL BE A DAILY CHC FOR SHOWERS
OR STORMS SATURDAY AND SUNDAY BUT COVERAGE WILL BE LOWER AS
SLIGHTLY DRIER AIR BEGINS TO WORK INTO THE REGION. WITH LESS
CONVECTION AND CLOUDS...AFTN TEMPERATURES WILL BEGIN A WARMING
TREND.
BY EARLY NEXT WEEK...THE HIGH WILL RETROGRADE FURTHER WEST AS A
SHORTWAVE TROF DIGS OVER THE ERN STATES...WITH THE SYSTEM
GRADUALLY AMPLIFYING OVER THE CONUS. THIS WILL LEAD TO A DEEPENING
NLY FLOW THAT WILL PUSH A SFC FRONT INTO THE AREA BY TUESDAY. RAIN
CHCS WILL BUMP BACK UP IN ADVANCE OF THE FRONT MONDAY INTO
TUESDAY. GLOBAL MODELS ARE IN GENERAL AGREEMENT REGARDING THE
DEVELOPMENT OF THIS AMPLIFIED SYSTEM AND ASSOCIATED SFC
FROPA...AND KEEPING THE AREA UNDER A NLY FLOW ALOFT THROUGH THE
LATTER PART OF THE WEEK. SHOULD THIS SCENARIO PAN OUT...DRIER MORE
COMFORTABLE CONDITIONS CAN BE EXPECTED FROM WEDNESDAY THROUGH
FRIDAY WITH SLIGHTLY BELOW NORMAL LOWS IN THE UPPER 60S TO LOWER
70S AND HIGHS NEAR NORMAL IN THE LOWER 90S.
24
MARINE...
A LT TO OCCASIONALLY MDT ONSHORE FLOW AND LOW SEAS WILL PERSIST
THROUGH EARLY NEXT WEEK AS HIGH PRES CONTINUES TO RIDGE OVER THE
GULF. A LINGERING DISTURBANCE OVER THE REGION WILL ALLOW FOR SCT
SHOWERS AND TSTMS TODAY...BUT RAIN CHCS WILL DECREASE OVER THE
WEEKEND AS HIGH PRES BUILDS ALOFT. A FRONT WILL MOVE SOUTH INTO
THE AREA BY LATE MONDAY INTO TUESDAY...BRINGING ANOTHER CHC FOR
SHOWERS OR TSTMS. AT THIS TIME...MODEL GUIDANCE SHOWS THIS FRONT
MOVING SOUTH OVER THE COASTAL WATERS ZONES...WITH OFFSHORE FLOW
AND DRIER WEATHER POSSIBLE FOR THE MIDDLE AND LATTER PART OF NEXT
WEEK.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 92 74 94 75 / 70 20 30 10
LCH 85 77 90 77 / 60 20 30 10
LFT 87 76 91 76 / 70 20 30 10
BPT 84 77 90 77 / 80 20 30 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
PUBLIC...08
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
810 AM CDT FRI AUG 21 2015
...SOUNDING DISCUSSION...
WINDS THROUGHOUT THE ATMOSPHERE ARE FROM THE SOUTHWEST ALLOWING
FOR MOISTURE TO REMAIN OVER THE AREA WITH A PRECIPITABLE WATER
VALUE OVER 2 INCHES. A SURFACE INVERSION AND LIGHT WINDS HAVE
ALLOWED FOR SOME FOG TO FORM WITH VISIBILITIES BEING REDUCED
GENERALLY BETWEEN 5 TO 10 MILES WHERE IT HAS FORMED. GOOD BOUNDARY
LAYER MIXING WILL OCCUR WITH MAINLY CLEAR SKIES THROUGH MID-
MORNING ALLOWING THE INVERSION TO BE REMOVED. THE CONVECTIVE
TEMPERATURE OF 86 SHOULD BE REACHED ACROSS MOST OF THE AREA AROUND
NOON TODAY AND THE 12Z HRRR SHOWS CONVECTION INCREASING IN
COVERAGE EARLY THIS AFTERNOON.
12Z BALLOON INFO: A ROUTINE FLIGHT THIS MORNING THAT LASTED 103
MINUTES. THE BALLOON REACHED A HEIGHT OF 21.5 MILES ABOVE THE
GROUND BURSTING JUST EAST OF ABITA SPRINGS 10 MILES DOWNRANGE FROM
THE OFFICE.
ANSORGE
&&
.PREV DISCUSSION... /ISSUED 340 AM CDT FRI AUG 21 2015/
SHORT TERM...
COLD FRONT STALLED OVER SOUTHERN ARK THIS MORNING WILL BEGIN TO
MOVE BACK TO THE NORTH LATER TODAY. THIS FRONT WILL BE REPLACED
WITH A SECOND FRONT MOVING INTO THE SOUTHERN ARK AREA MONDAY. THIS
SYSTEM WILL STALL FOR ABOUT 12 HOURS BEFORE MOVING SOUTHWARD ONCE
AGAIN MON NIGHT. THE AERA OF SH/TS WILL BE DEVELOPING ALONG THE
PREFRONTAL TROUGH THAT MOVES OUT AHEAD OF THE ACTUAL COLD FRONT. THIS
WILL SEND A GOOD ROUND OF SH/TS THROUGH THE AREA LATE MONDAY AND
POSSIBLY THROUGH MONDAY NIGHT. THE FRONT WILL BE ROUGHLY 10 TO 12 HOURS
BEHIND THE PREFRONTAL TROUGH AND SHOULD MOVE THROUGH LATE TUESDAY.
THIS WILL BE NOTICED AS DP TEMPS WILL DROP BACK INTO THE LOWER
60S. THIS IS STILL SEVERAL DAYS AWAY. BUT THE UPPER LONG WAVE
TROUGH DROPS INTO THE AREA AS WHAT IS LEFT OF DANNY IS BEING
PICKED UP BY IT. THIS SETS SOME HIGHER CONFIDENCE IN THIS FRONT
MAKING IT THROUGH THE AREA SINCE THE MOVEMENT OF ONE AREA OF LARGE
SCALE MASS MOVES NORTH SOMETHING EQUAL WILL NEED TO MOVE SOUTH OR
VICE VERSA. THE ONLY OTHER THING TO WATCH FOR WITH THIS SCENARIO
WILL BE THE POSSIBILITY OF SOME STRONG OR SEVERE TS ACTIVITY
MONDAY EVENING. WILL FIND BETTER TIMING AND STRENGTH OF THIS
SCENARIO WITH FUTURE FCASTS.
LONG TERM...
IF THE COLD FRONT MOVES THROUGH AND CLEARS THE AREA...WED THROUGH
THE REMAINDER OF THE WEEK IS LOOKING FANTASTIC.
AVIATION...
VFR CONDITIONS WILL GENERALLY PREVAIL THROUGH THE PERIOD. MVFR CIGS
MAY DEVELOP FOR A COUPLE HOURS NEAR DAYBREAK. WINDS WILL GENERALLY
REMAIN LESS THAN 10 KTS...EXCEPT FOR IN THE VICINITY OF SHOWERS AND
THUNDERSTORMS. SCATTERED CONVECTION IS EXPECTED TO DEVELOP THIS
AFTERNOON AND TEMPO GROUPS HAVE BEEN INCLUDED AT MOST SITES DURING
THE 18Z TO 22Z TIME FRAME.
MARINE...
GENERALLY TRANQUIL CONDITIONS WILL PREVAIL THROUGH THE PERIOD AS
WINDS ARE EXPECTED TO REMAIN 10 KNOTS OR LESS WITH WAVES NO HIGHER
THAN 2 FEET. ONLY REAL EXCEPTION WILL BE IN THE VICINITY OF
SCATTERED SHOWERS AND THUNDERSTORMS...WHERE STRONGER WINDS AND
ROUGHER SEAS WILL BE POSSIBLE. A WEAK FRONTAL BOUNDARY IS EXPECTED
TO SLIDE THROUGH THE AREA AND RESULT IN PREVAILING OFFSHORE FLOW BY
WEDNESDAY.
DECISION SUPPORT...
DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 89 73 94 74 / 60 20 40 10
BTR 92 74 94 75 / 60 20 40 10
ASD 90 75 91 76 / 60 20 40 10
MSY 90 77 91 77 / 50 20 40 10
GPT 90 78 90 78 / 50 20 30 10
PQL 90 77 90 77 / 50 20 30 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1051 PM EDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 1051 PM EDT SAT AUG 22 2015
SKIES REMAIN CLEAR ACROSS OUR ENTIRE CWA LATE THIS EVENING BETWEEN HIGH
PRESSURE CENTERED EAST OF MICHIGAN AND A STRONG COLD FRONT NOW
MOVING INTO THRU THE UPPER MISSISSIPPI VALLEY. LONG LINE OF
STRONG/SVR CONVECTION REMAINS ALONG AND JUST AHEAD OF THE FRONT.
LEADING EDGE OF THIS CONVECTION IS STILL WELL WEST OF OUR CWA OVER
WRN WISCONSIN. LATEST NAM12...RAP13 AND HRRR ALL SUGGEST THAT THIS
CONVECTION WILL NOT REACH OUR CWA UNTIL AFTER 12...ACTUALLY MORE
TOWARD 15Z. DO EXPECT SOME INCREASE IN MID/HIGH CLOUDS FOR THE FAR
WRN SECTIONS OF OUR CWA OVERNIGHT AS ASSOCIATED CLOUD COVER
REMAINS CLOSE TO THE FRONT ITSELF.
&&
.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 328 PM EDT SAT AUG 22 2015
HIGH IMPACT WEATHER: NONE
OVERVIEW...THE MAIN CONCERN WITH THE FORECAST PACKAGE IS THE STORMS
SYSTEM WEST OF US. THE MAIN LOW IS CURRENTLY SOUTH OF LAKE WINNIPEG,
WITH A WARM FRONT THAT JUTS EAST, IN NW ONTARIO, AND A COLD FRONT
THAT STRETCHES SOUTH INTO EASTERN NORTH DAKOTA, TO A SFC LOW IN
SOUTH DAKOTA, THEN SOUTHWEST THROUGH NEBRASKA AND WEST BACK INTO THE
INTERMOUNTAIN WEST. AT 500 MB, THE TROUGH TO THE WEST, JUST BEHIND
THE SFC LOW, HAS AN AXIS THAT RUNS ALONG THE MONTANA/ND BOARDER AND
ANOTHER SHORTWAVE TROUGH MOVING THROUGH THE UPPER MISSISSIPPI
VALLEY.
OTHERWISE HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WITH THE
RETURN FLOW JUST GETTING INTO THE UPPER GREAT LAKES, AND WARMING THE
REGION AND PROVIDING THE MOISTURE.
TONIGHT...ISOLATED RAIN SHOWERS IN NE LOWER WILL CONTINUE UNTIL
ABOUT SUN DOWN, SINCE THE MAIN REASON IS FROM THE DIURNAL CU. AS
THESE DIMINISH, THE CLOUDS WILL BEGIN TO CLEAR OUT AS WELL PRODUCING
A MAINLY QUIET, CLEAR SKY, WITH A LIGHT WARM BREEZE OVERNIGHT.
TEMPERATURES DON`T LOOK LIKE THEY WILL FALL MUCH AS THE RETURN FLOW
CONTINUES PUMP WARM AIR INTO THE REGION. IT COULD ALSO HAPPEN THAT
THE TEMPERATURES FALL A BIT, AND FLAT LINE IN THE MID TO UPPER 60S
OVERNIGHT, BUT IT SEEMS THAT TEMPERATURES WILL FALL INTO THE LOWER
TO MID 60S FIRST. AFTER 09Z, WE SHOULD START TO SEE SOME HIGHER
CLOUDS ADVANCING INTO THE WESTERN COUNTIES AHEAD OF THE SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH COLD FRONT. THERE IS A SMALL CHANCE
THAT A SHOWER MAY RUN INTO MANISTEE OR FRANKFORT BETWEEN 09Z AND
12Z, BUT THINK THAT THE MOISTURE AND INSTABILITY LOOKS WEAK AT THIS
POINT, SO WILL KEEP IT TO THE WEST SIDE OF LAKE MICHIGAN.
&&
.SHORT TERM...(SUNDAY THROUGH TUESDAY)
ISSUED AT 328 PM EDT SAT AUG 22 2015
HIGH IMPACT WEATHER: STRONGER STORMS SUNDAY...WATERSPOUT POTENTIAL
MONDAY-MONDAY NIGHT.
PATTERN OVERVIEW/FORECAST: LONG WAVE TROUGH HAS SET UP SHOP ACROSS
WESTERN CANADA...DIPPING INTO THE NRN CONUS COURTESY OF TWO DISTINCT
WAVES ROTATING THROUGH THE LARGER SCALE MEAN TROUGH. ONE PRONOUNCED
WAVE IN THE GULF OF ALASKA DELIVERING ACTIVE WEATHER TO THE WEST
COAST OF CANADA. SECOND STRONG WAVE (AND OUR MORE IMMEDIATE CONCERN)
ADVANCING THROUGH THE NRN PLAINS/SOUTH-CENTRAL CANADA REGION. STRONG
UPPER JET STREAK IS DIGGING INTO THE BACKSIDE OF THE WAVE AS A WEDGE
OF SUBSTANTIALLY COLDER AIR DIVES THROUGH THE NRN ROCKIES AND
HEADING INTO THE NRN PLAINS (AND EVENTUALLY...US). CORRESPONDING
DEEPENING SFC LOW IS LOCATED OVER THE DAKOTAS AND ATTENDING COLD
FRONT STRETCHING BACK INTO THE ROCKIES.
NRN PLAINS WAVE IS FORECAST TO GO "NEGATIVE TILT" AND CARVE OUT A
RATHER IMPRESSIVE (AND PSEUDO-CUTOFF) CLOSED LOW OVER THE GREAT
LAKES HEADING INTO MONDAY. THIS WILL DELIVER A RATHER UNSEASONABLY
COLD POCKET OF AIR TO THE GREAT LAKES AND MIDWEST (SREF GUIDANCE
DELIVERS A CORE OF +2C TO +4C 850 MB AIR RIGHT OVER NRN MICHIGAN
MONDAY NIGHT INTO TUESDAY). HOWEVER...MEAN LONG WAVE TROUGH IS
FORECAST TO REMAIN LARGELY ACROSS WESTERN (OR NORTHWESTERN) NOAM
THROUGH THE UPCOMING WEEK...SUGGESTING OUR IMPENDING DIVE INTO EARLY
FALL-LIKE WEATHER WILL BE SHORT LIVED AND SHOULD EVENTUALLY
TRANSITION BACK OUT TO MORE SEASONABLE READINGS BY LATE IN THE WEEK.
SUNDAY...NEGATIVELY TILTED SHORT WAVE TROUGH AXIS WILL BE SWINGING
UP THROUGH THE WESTERN GREAT LAKES/NRN MICHIGAN THROUGH THE COURSE
OF THE DAY. PARENT OCCLUDING LOW PRESSURE CENTER ADVANCES SLOWLY
INTO ONTARIO WITH ATTENDING OCCLUDING/COLD FRONT SLIDING ACROSS THE
CWA...MAINLY DURING THE AFTERNOON PER CURRENT GUIDANCE TIMING. AHEAD
OF THE FRONT...NARROW AXIS OF MOISTURE/INSTABILITY WILL BE NOSING UP
THROUGH THE CWA AHEAD OF THE FRONT AND THERE SHOULD BE PLENTY OF
FORCING (UPPER LEVEL HEIGHT FALLS AND LOW LEVEL CONVERGENCE) TO
MARCH A TIGHT NARROW CORRIDOR OF SHOWERS AND THUNDERSTORMS ACROSS
THE CWA...LATE MORNING THROUGH THE AFTERNOON. HAVE ADDED SOME 3-
HOURLY TIMING DETAIL TO THE FORECAST FOR SUNDAY BUT OF COURSE THAT
IS SUBJECT TO CHANGE. BUT IN ESSENCE...ANTICIPATED SHOWERS/STORMS TO
IMPACT THE WESTERN HALF OF THE CWA THROUGH MIDDAY AND EASTERN HALF
DURING THE AFTERNOON INTO EARLY EVENING.
SEVERE WEATHER POTENTIAL...DECENT FORCING AND MODESTLY STRONGER
WINDS ALOFT/30-40 KNOTS 0-6KM BULK SHEAR COULD SUPPORT SOME STRONGER
UPDRAFTS PARTICULARLY DOWN TOWARD SAGINAW BAY INTO SRN LOWER
MICHIGAN. INSTABILITY IS NOT SO IMPRESSIVE HOWEVER...BUT GIVEN THE
STRONG DYNAMICS/KINEMATICS...CERTAINLY CANNOT RULE OUT A MARGINAL
SEVERE WEATHER THREAT TOMORROW AFTERNOON...ESPECIALLY ACROSS THE
S/SE PART OF THE CWA WHERE BEST INSTABILITY AND STRONGER SHEAR
WILL BE FOUND.
SUNDAY NIGHT-TUESDAY...SIMPLY STATED...TURNING FALL-LIKE WITH RAIN
SHOWERS. SORT OF A TRANSITION PERIOD SUNDAY NIGHT THROUGH EARLY
MONDAY AS COLD FRONT AND NARROW LINE OF SHOWERS/STORMS EXIT ACROSS
LAKE HURON EARLY SUNDAY EVENING...AND WE GET SOME SEMBLANCE OF A DRY
SLOT SLIPPING THROUGH THE REGION THROUGH MONDAY MORNING. CORE OF
COLDEST AIR ARRIVES MONDAY NIGHT...BUT INITIAL COLD ADVECTION BEHIND
THE FRONT DROPS LOW LEVEL TEMPS (H8) TO AROUND 7C SUNDAY NIGHT. AND
WITH SOME BETTER MOISTURE STARTING TO ROTATE THROUGH UPPER
MICHIGAN/NRN LAKE MICHIGAN...WILL PROBABLY SEE SOME LAKE
EFFECT/ENHANCED RAIN SHOWERS GET GOING AS EARLY AS SUNDAY NIGHT
THROUGH MONDAY MORNING.
BUT THE REALLY GOOD STUFF WILL RAMP UP LATER MONDAY AND MONDAY
NIGHT AS SECONDARY SFC TROUGH/COLD FRONT SWINGS THROUGH USHERING
IN EVEN COLDER AIR (<4C) AND (MORE IMPORTANTLY) SOME QG-FORCING
FOR ASCENT AND BETTER MOISTURE. LAKE EFFECT/HEATING INDUCED RAIN
SHOWERS SHOULD REALLY TAKE OFF MONDAY AFTERNOON AND PERSIST
THROUGH MONDAY NIGHT AS WELL AS MUCH OF TUESDAY. WILL CARRY SOME
HEFTY POPS ACROSS MUCH OF THE CWA THROUGH THAT TIME WITH AN
EMPHASIS ACROSS THE USUAL W-NW LAKE EFFECT AREAS. DON/T HAVE SMALL
HAIL/GRAUPEL MENTIONED JUST YET BECAUSE THE NEEDED INSTABILITY
JUST DOESN/T APPEAR TO BE THERE. BUT SOMETHING TO KEEP IN MIND AS
WELL.
TEMPS...STILL RELATIVELY WARM ON SUNDAY. COLDER AIR SPILLS IN SUNDAY
NIGHT AND WE THEN STRUGGLE IN THE 60S BOTH MONDAY AND TUESDAY FOR
MOST AREAS. TUESDAY IS THE "COLDEST" AND I WOULDN/T BE SURPRISED TO
SEE A FEW SPOTS (GAYLORD) NOT MAKE IT OUT OF THE 50S (HAVE UNDERCUT
ALL GUIDANCE MAX TEMPS FOR TUESDAY).
&&
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 328 PM EDT SAT AUG 22 2015
RAIN CHANCES WILL BEGIN TO DIMINISH FOR EASTERN PARTS OF THE STATE
TUESDAY NIGHT GOING INTO WEDNESDAY AS THE CUTOFF LOW OVER ONTARIO
LIFTS INTO QUEBEC. HOWEVER...WILL HAVE TO DIVERGE A BIT FROM BLENDED
MODEL GUIDANCE GOING INTO THURSDAY FOR WESTERN PORTIONS OF THE
STATE. WITH SUFFICIENT MOISTURE LOOKING TO STAY AROUND...AND H8
TEMPS REMAINING LOW ENOUGH FOR LAKE PROCESSES TO KICK IN...WILL ADD
CHANCE POPS FOR SOME POSSIBLE LAKE EFFECT SHOWERS TO STICK AROUND
THROUGH THURSDAY. WILL ALSO LEAVE CHANCE POPS OVER THE WEEKEND...AS
A QUICK MOVING SHORTWAVE DIVING THROUGH CANADA AND A COLD FRONT
ATTENDANT TO LOW PRESSURE NEAR HUDSON BAY TRANSITING THE AREA COULD
HELP TO KICK OFF SOME SHOWERS. AFTER A COUPLE OF COOL
DAYS...TEMPERATURES SHOULD MODERATE THROUGH THE EXTENDED PERIOD
GETTING BACK TO NEAR NORMAL FOR MOST AREAS BY SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 700 PM EDT SAT AUG 22 2015
VFR CONDITIONS WILL HOLD ON ACROSS ALL NRN LWR MICHIGAN TAF SITES
THRU TONIGHT...ALTHOUGH MID AND HIGH CLOUDS WILL GRADUALLY
INCREASE FROM WEST TO EAST OVERNIGHT AHEAD OF AN APPROACHING
STRONG COLD FRONT. ALSO...LLWS WILL DEVELOP OVERNIGHT AS LOW
LEVELS DECOUPLE AND WINDS JUST OFF THE DECK STRENGTHEN AHEAD OF
THE COLD FRONT. WIDESPREAD SHOWERS AND THUNDERSTORMS WILL ARRIVE
ACROSS NW LWR MICHIGAN (PLN/TVC/MBL) JUST AFTER 12Z SUNDAY ALONG
AND AHEAD OF THAT COLD FRONT. SOME STRONG/POSSIBLY SVR STORMS ARE
POSSIBLE. CONVECTION WILL REACH FAR NE LWR MICHIGAN (APN) BY EARLY
AFTERNOON AS THE FRONT SWEEPS THRU THE REGION.
&&
.MARINE...
ISSUED AT 328 PM EDT SAT AUG 22 2015
TONIGHT THROUGH MONDAY...WINDS TONIGHT WILL BEGIN TO INCREASE
ESPECIALLY AFTER 06Z/SUN AS THE SFC HIGH MOVES EAST AND THE GRADIENT
TIGHTENS THROUGH THE NIGHT. BY SUNDAY MORNING (AROUND 12Z) THE WINDS
SHOULD BE HIGH ENOUGH ALONG THE LAKE MICHIGAN AND SHORE AND IN
WHITEFISH BAY FOR SMALL CRAFT ADVISORIES. WITH THE COLD FRONT MOVING
ACROSS THE LAKE SUNDAY MORNING, AND THEN ACROSS NORTHERN MICHIGAN
DURING THE DAY, WILL EXPECT THAT LAKE HURON WILL GET IN ON THE ACT,
SO SMALL CRAFT ADVISORIES WILL BE ADDED FOR THERE AS WELL. THE
ADVISORIES WILL CONTINUE INTO THE NIGHT POST-FRONTAL, ALTHOUGH WITH
THE SFC LOW MOVING OVER LAKE SUPERIOR, THE GRADIENT WILL SLACKEN SO
THE SMALL CRAFT WON`T BE NEEDED FOR WHITEFISH BAY AND THE ST. MARY`S
RIVER. IT LOOKS LIKE WE WILL PROBABLY NEED TO CONTINUE THE
ADVISORIES INTO MONDAY AS THE GRADIENT STILL LOOKS FAIRLY TIGHT OVER
N LOWER.
IN ADDITION TO THE GUSTY WINDS/HIGHER WAVES...AN UNSEASONABLY COLD
AIRMASS WILL SLIP ACROSS THE GREAT LAKES MONDAY THROUGH
TUESDAY...DELIVERING WIDESPREAD LAKE EFFECT RAIN SHOWERS.
WATERSPOUTS WILL ALSO BE A POSSIBILITY WITH THE BEST TIMEFRAME
LOOKING TO BE MONDAY AFTERNOON THROUGH MONDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM 11 AM SUNDAY TO 6 AM EDT MONDAY FOR
LHZ345>349.
LM...SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO 6 AM EDT MONDAY FOR
LMZ323-341-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO MIDNIGHT EDT SUNDAY
NIGHT FOR LSZ321-322.
&&
$$
UPDATE...MLR
NEAR TERM...JSL
SHORT TERM...ADAM
LONG TERM...ALM
AVIATION...MLR
MARINE...ADAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EDT FRI AUG 21 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 316 PM EDT FRI AUG 21 2015
WEATHER REMAINS QUIET INTO SATURDAY WITH WARMING TREND. IN THE REAL
NEAR TERM...TRYING TO FIGURE OUT IF THE HRRR AND RAP SHOWING A FEW
BLIPS ON THE MODELED REFLECTIVITY ARE REALISTIC. REGIONAL RADAR LOOP
HAS SHOWN ISOLD ECHOES OVER NORTHERN WI...BUT ONLY OBS SHOWING LGT
RAIN ARE OVER WCNTRL WI CLOSER TO MUCAPES OF A FEW HUNDRED J/KG.
ANOTHER AGITATED AREA OF MID CLOUDS AND ISOLD SHRA IS OVER MN
ARROWHEAD. MAIN SHORTWAVE DRIVING THAT AREA OF WX IS LIFTING OVER
NORTHERN ONTARIO INSTEAD OF TOWARD UPR MICHIGAN. OVER THE CWA REST
OF THIS AFTN...HRRR AND RAP SOUNDINGS SHOW NARROW LAYER OF MOISTURE
AROUND H7 WITH DRY AIR BLO AND ABOVE. GOING TO KEEP IT DRY WITH JUST
INCREASING MID CLOUDS LATE THIS AFTN INTO THE EVENING.
FOR REST OF SHORT TERM...STRONG UPPER LEVEL TROUGH OVER SOUTHERN
BRITISH COLUMBIA THIS AFTN DIGS ACROSS ROCKIES OF ALBERTA AND
MONTANA TONIGHT INTO SATURDAY MORNING WITH SFC TROUGH OVER MONTANA
THIS AFTN DEEPENING TO A 995-1000MB SFC LOW OVER DAKOTAS BY 12Z
SATURDAY. SINCE SFC LOW AND COLD FRONT REMAIN TO THE WEST OF UPR
MICHIGAN THROUGH EARLY SATURDAY EVENING...APPEARS TO BE A
DRY...WARM...AND WINDY DAY IN THE WARM SECTOR OF THE SFC LOW. WINDS
HAVE POTENTIAL TO BE QUITE GUSTY WITH EASILY 25-30 KTS IN THE MIXED
LAYER ON SATURDAY AFTN. IN ADDITION...PRESSURE GRADIENT WILL BE
TIGHT AS UPR MICHIGAN IS BETWEEN THE APPROACHING SFC LOW AND
DEPARTING HIGH OVER THE LOWER GREAT LAKES. DECENT AGREEMENT FM
NAM/GFS/GEM-REGIONAL ON THE WINDS/WIND GUSTS FOR SATURDAY. COULD SEE
WIND GUSTS 30 TO POSSIBLY 40 MPH DURING PEAK HEATING ON SATURDAY
AFTN.
THERE IS A CAVEAT FOR THE MIXING STRENGTH THOUGH. NOT A LOT OF CLOUD
COVER EXPECTED AS MOST MID CLOUDS THAT MOVE THROUGH INTO EARLY THIS
EVENING WILL BE NORTH AND EAST OF THE AREA ON SATURDY. YET...LIKELY
WILL SEE FILTERED OR DIMMED SUNSHINE AS WIDESPREAD AREA OF SMOKE
ALOFT OVER THE ROCKIES AND PLAINS TODAY /25KFT AGL PER MANUAL SFC
OBS FM DAKOTAS TO MINNESOTA/ MOVES OVER THE UPPER GREAT LAKES BASED
ON EXPECTED WINDS IN THE SMOKE LAYER /H4-H3/. ALWAYS TOUGH TO
PREDICT EXACT COVERAGE AND THICKNESS OF SMOKE LAYER...BUT GIVEN ALL
THE SMOKE UPSTREAM THIS AFTN...TRENDED HIGHER ON THE SKY COVER TO AT
LEAST GO PARTLY CLOUDY INSTEAD OF SUNNY. DURING OTHER BOUTS EARLIER
THIS SUMMER WITH SMOKE ALOFT...MIXING WAS HELD DOWN MORE THAN WHAT
YOU WOULD NORMALLY EXPECT...SO THAT MAY OCCUR AGAIN. BASED ON
FORECAST H85 TEMPS OF 16-18C...TEMPS SHOULD REACH THE 80S AWAY FM
LAKE MICHIGAN. CAPPED READINGS IN THE LOW TO MID 80S...WARMEST ALONG
LK SUPERIOR DUE TO STRONG/GUSTY SOUTH WINDS PROVIDING DOWNSLOPING
WARMING. TEMPS NEAR LK MICHIGAN WILL REACH UPPER 70S. WILL BE BUMPY
AGAIN FOR WINDS/WAVES ON NORTHERN LK MICHIGAN ESPECIALLY ON SATURDAY
AFTN DUE TO THE INCREASING SOUTH WINDS. PROBABLY WILL NEED ANOTHER
SMALL CRAFT ADVISORY FOR THE MARINE INTERESTS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 401 PM EDT FRI AUG 21 2015
THE END OF THE WEEKEND WILL BE FAIRLY ACTIVE WEATHER WISE...WITH
ANOTHER AUTUMN LIKE COLD FRONT MOVING THROUGH THE AREA ON SUNDAY.
THE MODELS ARE IN GOOD AGREEMENT ON TIMING OF THE FRONTAL PASSAGE
ACROSS THE AREA BEING SUNDAY MORNING...WITH MUCH COOLER AIR MOVING
ACROSS THE AREA LATER SUNDAY NIGHT INTO MONDAY AS THE UPPER LOW
SETTLES JUST NORTH OF LAKE SUPERIOR. AS SUCH...WILL KEEP LIKELY POPS
SPREADING WEST TO EAST LATER SATURDAY NIGHT INTO SUNDAY MORNING. DUE
TO THE TIMING OF THE FRONTAL PASSAGE DURING THE NIGHT AND EARLY
MORNING HOURS...DO NOT EXPECT WIDESPREAD THUNDERSTORM ACTIVITY.
HOWEVER...CANNOT RULE OUT STORMS DEVELOPING OVER MN EARLY SAT
EVENING WITH THE RESIDUAL MOVING INTO UPPER MI OVERNIGHT. AS
SUCH...WILL KEEP THUNDER CHANCES IN THE FORECAST AHEAD OF THE FRONT.
AFTER FROPA...EXPECT SCATTERED RAIN SHOWERS IN THE CYCLONIC
FLOW...ALTHOUGH THERE WILL LIKELY BE A LULL IN THE PCPN IMMEDIATELY
BEHIND THE COLD FRONT SUNDAY IN THE DRY SLOT. BEST CHANCES FOR
SHOWER ACTIVITY WILL BE LATER SUNDAY NIGHT INTO MONDAY DOWNWIND OF
LAKE SUPERIOR WHERE SOME LAKE EFFECT RAIN IS POSSIBLE DUE TO 850MB
TEMPS DROPPING TO +4C YIELDING LAKE INDUCED INSTABILITY WITH WATER
TEMPS AROUND +15C ESPECIALLY ACROSS THE WESTERN BASIN. AS
SUCH...WILL MAINTAIN NUMEROUS RAIN SHOWERS FOR SUNDAY NIGHT AND
MONDAY FOR NORTHWEST UPPER MICHIGAN AND SCATTERED SHOWERS ELSEWHERE.
TEMPERATURES ON SUNDAY WILL LIKELY DROP DURING THE DAY WHILE TEMPS
ON MONDAY WILL BE LUCKY TO RISE OUT OF THE 50S. IN FACT...WITH 850MB
TEMPS BEING SO COLD...IF IT REMAINS CLOUDY ALL DAY THERE MAY BE SPOT
OR TWO THAT STAYS IN THE UPPER 40S/LOWER 50S ON MONDAY.
REGARDLESS...MONDAY WILL FEEL QUITE LIKE AUTUMN WITH BREEZY
CONDITIONS AND COOL TEMPERATURES.
WITH THE UPPER LOW BECOME CLOSED OFF NORTH OF THE AREA...WE WILL SEE
PERSISTING DEEP CYCLONIC NW FLOW THROUGH TUESDAY WITH DEEP MOISTURE
REMAINING ACROSS THE AREA. WILL NEED TO MAINTAIN SCATTERED SHOWERS
MONDAY NIGHT CLOSER TO LAKE SUPERIOR...THEN SLOWLY TAPERING FROM
WEST TO EAST DURING THE DAY ON TUESDAY AS THE UPPER LOW IS FORECAST
TO MOVE EAST YIELDING TO CONFLUENT NW FLOW ALOFT. QUIET BUT STILL
COOL WEATHER EXPECTED ON WEDNESDAY WITH HIGH PRESSURE IN CONTROL AND
UPPER HEIGHTS RISE. NEXT CHANCE FOR PRECIPITATION WILL BE LATE
THURSDAY INTO FRIDAY MORNING WITH THE NEXT SYSTEM MOVING THROUGH THE
NW FLOW ALOFT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 215 PM EDT FRI AUG 21 2015
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD. SCATTERED MID
CLOUDS THIS AFTN AND A THICK SMOKE LAYER ALOFT TONIGHT INTO
SATURDAY. GUSTY SOUTH WINDS AT KIWD REST OF THE AFTN WILL GIVE WAY
TO LOW-LEVEL WIND SHEAR BY MIDNIGHT TONIGHT AS WINDS DIMINISH AT THE
SFC. WINDS WILL ALSO BECOME GUSTY FOR A TIME AT KSAW THIS AFTN AS
WELL. EXPECT STRONG AND GUSTY SOUTH WINDS AT ALL TAF SITES ON
SATURDAY ONCE LOW-LEVEL INVERSION BREAKS BY MID MORNING. WIND GUSTS
SATURDAY AFTN COULD TOP OUT NEAR 30 KTS AT KIWD AND KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 316 PM EDT FRI AUG 21 2015
S WINDS INCREASE TO 25 KTS TONIGHT UNDER SHARPENING PRES GRADIENT
BETWEEN THE DEPARTING RIDGE AND A DEEP LOW PRESSURE SYSTEM MOVING
FROM THE NORTHERN PLAINS INTO ONTARIO. MAY SEE GUSTS TO 30 KTS OVER
EASTERN LK SUPERIOR ON SATURDAY AFTN. STEADY S WINDS WILL VEER
TOWARD THE W FOLLOWING A COLD FRONTAL PASSAGE ON LATE SAT NIGHT/SUN
AND INCREASE UP TO 30 KTS. DEPENDING ON THE INTENSITY OF A LOW
PRESSURE SYSTEM MOVING SLOWLY NE THRU ONTARIO...THERE COULD BE SOME
MARGINAL GALES TO 35 KTS AT TIMES ON SUN INTO MON WITH THE ARRIVAL
OF COOLER AIR/MORE DESTABILIZATION OVER THE RELATIVELY WARM LAKE
WATERS AS THE FLOW CONTINUES TO VEER TO THE NW UNDER TIGHT PRES
GRADIENT AHEAD OF APPROACHING HI PRES RIDGE FROM THE NORTHERN
PLAINS. AS THE HI MOVES CLOSER AND THE GRADIENT SLACKENS...EXPECT
WINDS TO DIMINISH LATER TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...MRD
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
317 PM EDT FRI AUG 21 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 316 PM EDT FRI AUG 21 2015
WEATHER REMAINS QUIET INTO SATURDAY WITH WARMING TREND. IN THE REAL
NEAR TERM...TRYING TO FIGURE OUT IF THE HRRR AND RAP SHOWING A FEW
BLIPS ON THE MODELED REFLECTIVITY ARE REALISTIC. REGIONAL RADAR LOOP
HAS SHOWN ISOLD ECHOES OVER NORTHERN WI...BUT ONLY OBS SHOWING LGT
RAIN ARE OVER WCNTRL WI CLOSER TO MUCAPES OF A FEW HUNDRED J/KG.
ANOTHER AGITATED AREA OF MID CLOUDS AND ISOLD SHRA IS OVER MN
ARROWHEAD. MAIN SHORTWAVE DRIVING THAT AREA OF WX IS LIFTING OVER
NORTHERN ONTARIO INSTEAD OF TOWARD UPR MICHIGAN. OVER THE CWA REST
OF THIS AFTN...HRRR AND RAP SOUNDINGS SHOW NARROW LAYER OF MOISTURE
AROUND H7 WITH DRY AIR BLO AND ABOVE. GOING TO KEEP IT DRY WITH JUST
INCREASING MID CLOUDS LATE THIS AFTN INTO THE EVENING.
FOR REST OF SHORT TERM...STRONG UPPER LEVEL TROUGH OVER SOUTHERN
BRITISH COLUMBIA THIS AFTN DIGS ACROSS ROCKIES OF ALBERTA AND
MONTANA TONIGHT INTO SATURDAY MORNING WITH SFC TROUGH OVER MONTANA
THIS AFTN DEEPENING TO A 995-1000MB SFC LOW OVER DAKOTAS BY 12Z
SATURDAY. SINCE SFC LOW AND COLD FRONT REMAIN TO THE WEST OF UPR
MICHIGAN THROUGH EARLY SATURDAY EVENING...APPEARS TO BE A
DRY...WARM...AND WINDY DAY IN THE WARM SECTOR OF THE SFC LOW. WINDS
HAVE POTENTIAL TO BE QUITE GUSTY WITH EASILY 25-30 KTS IN THE MIXED
LAYER ON SATURDAY AFTN. IN ADDITION...PRESSURE GRADIENT WILL BE
TIGHT AS UPR MICHIGAN IS BETWEEN THE APPROACHING SFC LOW AND
DEPARTING HIGH OVER THE LOWER GREAT LAKES. DECENT AGREEMENT FM
NAM/GFS/GEM-REGIONAL ON THE WINDS/WIND GUSTS FOR SATURDAY. COULD SEE
WIND GUSTS 30 TO POSSIBLY 40 MPH DURING PEAK HEATING ON SATURDAY
AFTN.
THERE IS A CAVEAT FOR THE MIXING STRENGTH THOUGH. NOT A LOT OF CLOUD
COVER EXPECTED AS MOST MID CLOUDS THAT MOVE THROUGH INTO EARLY THIS
EVENING WILL BE NORTH AND EAST OF THE AREA ON SATURDY. YET...LIKELY
WILL SEE FILTERED OR DIMMED SUNSHINE AS WIDESPREAD AREA OF SMOKE
ALOFT OVER THE ROCKIES AND PLAINS TODAY /25KFT AGL PER MANUAL SFC
OBS FM DAKOTAS TO MINNESOTA/ MOVES OVER THE UPPER GREAT LAKES BASED
ON EXPECTED WINDS IN THE SMOKE LAYER /H4-H3/. ALWAYS TOUGH TO
PREDICT EXACT COVERAGE AND THICKNESS OF SMOKE LAYER...BUT GIVEN ALL
THE SMOKE UPSTREAM THIS AFTN...TRENDED HIGHER ON THE SKY COVER TO AT
LEAST GO PARTLY CLOUDY INSTEAD OF SUNNY. DURING OTHER BOUTS EARLIER
THIS SUMMER WITH SMOKE ALOFT...MIXING WAS HELD DOWN MORE THAN WHAT
YOU WOULD NORMALLY EXPECT...SO THAT MAY OCCUR AGAIN. BASED ON
FORECAST H85 TEMPS OF 16-18C...TEMPS SHOULD REACH THE 80S AWAY FM
LAKE MICHIGAN. CAPPED READINGS IN THE LOW TO MID 80S...WARMEST ALONG
LK SUPERIOR DUE TO STRONG/GUSTY SOUTH WINDS PROVIDING DOWNSLOPING
WARMING. TEMPS NEAR LK MICHIGAN WILL REACH UPPER 70S. WILL BE BUMPY
AGAIN FOR WINDS/WAVES ON NORTHERN LK MICHIGAN ESPECIALLY ON SATURDAY
AFTN DUE TO THE INCREASING SOUTH WINDS. PROBABLY WILL NEED ANOTHER
SMALL CRAFT ADVISORY FOR THE MARINE INTERESTS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 407 AM EDT FRI AUG 21 2015
ALTHOUGH THE WEEKEND WL START ON A DRY AND WARMER NOTE...ANOTHER
POTENT SHRTWV DRIFTING E THRU THE NRN PLAINS TOWARD THE UPR LKS WL
BRING AN UNSETTLED PERIOD OF WX TO THE CWA LATE SAT NGT INTO EARLY
NEXT WEEK. TIMING/IMPACTS OF THIS DISTURBANCE ARE THE PRIMARY FOCUS
FOR THIS SHIFT. RIGHT NOW...THE ACCOMPANYING DYNAMIC FORCING LOOKS
SUFFICIENT TO JUSTIFY A PERIOD OF SOME HI LIKELY POPS AHEAD OF
ATTENDANT COLD FROPA FOR LATE SAT NGT THRU SUN DESPITE CONCERNS ON
MSTR INFLOW THAT WL LIMIT TS CHCS.
SAT...UPR MI WL REMAIN DOMINATED BY LARGE SCALE SUBSIDENCE/DRY
AIRMASS ASSOCIATED WITH SLOWLY EXITING UPR RDG TO THE E OF POTENT
SHRTWV MOVING INTO THE NRN PLAINS. GUSTY S FLOW BTWN SFC HI PRES
DRIFTING INTO THE MID ATLANTIC STATES AND LO PRES NEAR THE CNDN
BORDER/ATTENDANT COLD FNT MOVING INTO MN LATER IN THE DAY IS FCST TO
LIFT H85 TEMPS TO 16-18C...SUPPORTING HI TEMPS WELL INTO THE 80S
AWAY FM THE COOLING INFLUENCE OF LK MI WITH A GOOD DEAL OF SUNSHINE.
SAT NGT...ARRIVAL OF WARM CONVEYOR BELT MSTR RIBBON/SFC COLD FNT
OVER THE W HALF LATE SAT NGT AHEAD OF SHRTWV MOVING INTO MN WL BRING
A RETURN OF SHOWERS/SOME TS TO THAT AREA. DESPITE THE STRENGTH OF
THE INCOMING SHRTWV/SLY FLOW AHEAD OF THE FNT...OVERALL MSTR INFLOW
INTO UPR MI IS FCST TO BE SOMEWHAT LIMITED AND FOCUSED TO THE S IN
WI SO THAT ONLY A NARROW BAND OF PWAT ARND 1.50 INCHES IS SHOWN TO
MOVE INTO THE W OVERNGT. ARRIVAL OF THE FNT DURING PERIOD OF
NOCTURNAL COOLING WL ALSO BE A LIMITING FACTOR...WITH FCST MUCAPE NO
HIER THAN ABOUT 500-600 J/KG. BUT WITH 12HR H5 HGT FALLS UP TO 100M
AHEAD OF THE APRCHG SHRTWV THAT IS FCST TO BECOME CUTOFF AT H5...DID
RETAIN LIKELY POPS UNDER THE WARM CONVEYOR BELT. THE E HALF SHOULD
REMAIN DRY CLOSER TO DEPARTING SFC HI PRES TO THE E.
SUN...STRONG SHRTWV IS FCST TO DRIFT ONLY SLOWLY E THRU NRN MN...
PUSHING COLD FNT/WARM CONVEYOR BELT MSTR RIBBON TO NEAR NEWBERRY
LATE IN THE DAY. BAND OF SHOWERS WITH EMBEDDED TS IN PRESENCE OF
SOME DAYTIME HEATING WL DRIFT ACRS UPR MI ALONG THIS FNT UNDER AREA
OF SUPPORTING DEEP LYR QVECTOR CNVGC THAT MAY BE ENHANCED BY ANOTHER
DISTURBANCE ROTATING ARND THE SLOW MOVING CUTOFF H5 LO. ARRIVAL OF
SOME DEEP LYR QVECTOR DVGC/DRY SLOTTING WL DIMINISH THE SHOWER CHCS
W-E BEHIND THE FROPA...BUT AREA OF WRAP ARND LO-MID LVL MSTR IN
CONCERT WITH DAYTIME HEATING/UPSLOPE LLVL CYC W FLOW ARND LO PRES IN
ONTARIO MAY RESULT IN SOME MORE SHOWERS OVER THE W HALF IN THE AFTN.
H85 TEMPS ARE FCST TO FALL TO 6-8C OVER THE W HALF IN THE AFTN...SO
TEMPS MAY ACTUALLY FALL IN THAT AREA. THE 00Z NAM MODEL IS QUITE A
BIT SLOWER ON THE FROPA TIMING THAN THE OTHER MODELS AND WAS NOT
UTILIZED PER NCEP PREFERENCE.
SUN NGT THRU TUE...UPR MI IS FCST TO BE DOMINATED BY DEEP... STRONG
CYC NW FLOW OF COOL AIR ANRD STACKED CLOSED LO EXITING ONLY SLOWLY
TO THE ENE THRU ONTARIO. H85 TEMPS WL BE WITHIN A FEW DEGREES OF
5C...RESUTLING IN SOME COOL WX THAT WL BE MORE TYPICAL OF EARLY
FALL. GUSTY WINDS WITH H925 WINDS UP TO 30-35 KTS WL MAKE THE AIR
FEEL EVEN COOLER. COMBINATION OF THE SHARP CYC FLOW...POTENTIAL
EMBEDDED SHRTWVS ROTATING ARND THE CLOSED LO AND COOLNESS OF THE
AIRMASS OVER THE RELATIVELY WARM LK WATERS /WATER TEMPS OVER THE
OPEN WATERS OF WRN LK SUP ARE 15-17C/ WL RESULT IN NMRS SHOWERS...
ESPECIALLY OVER THE HIER TERRAIN OF THE NW HALF. GOING LIKELY POPS
IN THIS AREA SEEM ON TRACK. DAYTIME HEATING ON MON WL LIKELY RESULT
IN SCT SHOWERS EVEN AWAY FM THAT AREA. AS UPR HGTS GRDLY RISE ON TUE
AND THE LLVL CYC FLOW BEGINS TO WEAKEN ON TUE WITH THE CLOSER APRCH
OF TRAILING HI PRES...POPS/CLDS/GUSTY WINDS WL DIMINISH.
EXTENDED...TRAILING HI PRES WL BRING A DRY...SEASONABLE PERIOD ON
TUE NGT THRU WED NGT UNDER RISING HGTS TO THE E OF BLDG UPR RDG IN
THE PLAINS. DEPENDING ON HOW QUICKLY ANOTHER SHRTWV RIDES OVER THIS
RDG...SHOWER/TS CHCS MAY RETURN AS EARLY AS NEXT THU ALONG WITH SOME
WARMER WX.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 215 PM EDT FRI AUG 21 2015
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD. SCATTERED MID
CLOUDS THIS AFTN AND A THICK SMOKE LAYER ALOFT TONIGHT INTO
SATURDAY. GUSTY SOUTH WINDS AT KIWD REST OF THE AFTN WILL GIVE WAY
TO LOW-LEVEL WIND SHEAR BY MIDNIGHT TONIGHT AS WINDS DIMINISH AT THE
SFC. WINDS WILL ALSO BECOME GUSTY FOR A TIME AT KSAW THIS AFTN AS
WELL. EXPECT STRONG AND GUSTY SOUTH WINDS AT ALL TAF SITES ON
SATURDAY ONCE LOW-LEVEL INVERSION BREAKS BY MID MORNING. WIND GUSTS
SATURDAY AFTN COULD TOP OUT NEAR 30 KTS AT KIWD AND KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 316 PM EDT FRI AUG 21 2015
S WINDS INCREASE TO 25 KTS TONIGHT UNDER SHARPENING PRES GRADIENT
BETWEEN THE DEPARTING RIDGE AND A DEEP LOW PRESSURE SYSTEM MOVING
FROM THE NORTHERN PLAINS INTO ONTARIO. MAY SEE GUSTS TO 30 KTS OVER
EASTERN LK SUPERIOR ON SATURDAY AFTN. STEADY S WINDS WILL VEER
TOWARD THE W FOLLOWING A COLD FRONTAL PASSAGE ON LATE SAT NIGHT/SUN
AND INCREASE UP TO 30 KTS. DEPENDING ON THE INTENSITY OF A LOW
PRESSURE SYSTEM MOVING SLOWLY NE THRU ONTARIO...THERE COULD BE SOME
MARGINAL GALES TO 35 KTS AT TIMES ON SUN INTO MON WITH THE ARRIVAL
OF COOLER AIR/MORE DESTABILIZATION OVER THE RELATIVELY WARM LAKE
WATERS AS THE FLOW CONTINUES TO VEER TO THE NW UNDER TIGHT PRES
GRADIENT AHEAD OF APPROACHING HI PRES RIDGE FROM THE NORTHERN
PLAINS. AS THE HI MOVES CLOSER AND THE GRADIENT SLACKENS...EXPECT
WINDS TO DIMINISH LATER TUE INTO WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...KC
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DULUTH MN
1231 AM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 1228 AM CDT FRI AUG 21 2015
UPDATED AVIATION SECTION BELOW.
UPDATE ISSUED AT 636 PM CDT THU AUG 20 2015
UPDATED AVIATION SECTION BELOW. CLOUD COVER FORECAST IS CURRENTLY
ON TRACK AND EXPECT TO LOSE A LOT OF THE REMAINING CLOUD COVER
BETWEEN NOW AND 02Z...SETTING US UP FOR A FAIRLY GOOD RADIATIONAL
COOLING NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CDT THU AUG 20 2015
SHOWERS/DRIZZLE ENDING ACROSS THE ARROWHEAD EARLY THIS AFTERNOON
GIVING WAY TO SUNNY AND JUST BELOW SEASONABLE TEMPERATURES ACROSS
THE REGION. CLEAR SKIES AND NEAR-CALM WIND TONIGHT WITH A HIGH
PRESSURE BUILDING IN WILL LEAD TO COOL OVERNIGHT LOWS. SUNNY
AND WARMER ON FRIDAY WITH HIGHS NEAR 80.
ON THE SYNOPTIC SCALE THE BROAD LOW PRESSURE SYSTEM THAT BROUGHT
INTENSE RAINFALL TO THE REGION EARLIER THIS WEEK IS FINALLY
DEPARTING TO THE NORTHEAST. BEHIND THIS SOME LOW-LEVEL RIDGING WILL
BUILD IN TO THE UPPER MIDWEST AS A HIGH PRESSURE BUILDS FROM THE
TENNESSEE TO OHIO RIVER VALLEY. WARM AIR ADVECTION WILL RAMP UP DUE
TO WEST/SOUTHWESTERLY WINDS AT LOW LEVELS TONIGHT INTO TOMORROW. IN
ADDITION...A WEAK WARM FRONT ON THE LEADING EDGE OF THE WARM AIR
ADVECTION WILL MOVE ACROSS MANITOBA INTO NORTHWEST ONTARIO...WHICH
MAY GRAZE THE BORDERLAND WITH SOME SHOWERS OVERNIGHT. WHILE THERE IS
NOT MUCH SUPPORT FROM THE GLOBAL MODEL SUITE AS FAR AS QPF
GOES...MOST MODELS INDICATE THE NECESSARY FORCING WILL BE THERE FOR
A FEW SHOWERS. THE LATEST HRRR RUNS ARE ALSO SUPPORTIVE OF THIS
IDEA...SO INCLUDED SOME LOW POPS UP ALONG THE INTERNATIONAL FALLS
REGION. ON FRIDAY THE LOW-LEVEL RIDGING FLATTENS OUT WITH WEST-
SOUTHWEST FLOW ALOFT RESULTING IN CONTINUED WARM AIR ADVECTION. FOR
REFERENCE...THE 850MB TEMP FROM THIS MORNINGS 12Z SOUNDING AT
INTERNATIONAL FALLS WAS 3.1C...AND THE MODEL CONSENSUS IS FOR THIS
TO RISE TO ABOUT 18C BY FRIDAY AFTERNOON.
TONIGHT...GRADUALLY CLEARING SKIES WITH PATCHY FOG POSSIBLE. WINDS
BECOMING NEAR-CALM IN THE EVENING WHICH SHOULD ALLOW FOR FOG TO
DEVELOP...ESPECIALLY IN NORTHWEST WISCONSIN WHERE THE HEAVIEST
RAINFALL HAS FALLEN OVER THE PAST FEW DAYS. GUIDANCE NOT VERY
SUPPORTIVE OF THE FOG IDEA WHICH IS PROBABLY DUE TO THE DRIER AIR
MOVING IN FROM THE WEST...BUT WITH A WEAK RIDGE OVER THE REGION
TEMPS WILL FALL RAPIDLY AND AT LEAST PATCHY RADIATION FOG SHOULD
DEVELOP. LATER IN THE NIGHT...AFTER MIDNIGHT...SOME HIGH CLOUDS MAY
MOVE IN ACROSS FAR NORTH-CENTRAL MINNESOTA...AND POSSIBLY A SHOWER
OR TWO IN THE INTERNATIONAL FALLS REGION. FOG MAY DISSIPATE BEFORE
SUNRISE IF WINDS PICK UP BY EARLY FRIDAY MORNING...THIS WILL DEPEND
ON THE TIMING OF THE RIDGE AXIS BUT THINKING BY SUNRISE FOG SHOULD
BE GONE EVERYWHERE EXCEPT FOR NORTHERN WISCONSIN NEAR THE UP. LOWS
IN THE LOW/MID 40S TO LOW 50S.
FRIDAY...MOSTLY SUNNY...WARM...AND BREEZY. WINDS OUT OF THE SOUTH AT
10 TO 15 MPH WITH GUSTS TO NEAR 25 MPH. THERE MAY BE AN ISOLATED
SHOWER IN THE MORNING ACROSS THE BORDERLAND...BUT OTHERWISE DRY.
HIGHS IN THE UPPER 70S TO LOW 80S.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU AUG 20 2015
THE MAIN CONCERN FOR THE EXTENDED IS THE THREAT FOR SEVERE WEATHER
SATURDAY AFTERNOON AND NIGHT.
THE SOUTHERLY FLOW CONTINUES ACROSS THE FORECAST AREA FRIDAY NIGHT
OUT AHEAD OF THE SYSTEM. THE NAM AND ECMWF ARE SIMILAR WITH TAKING
THE CENTER ACROSS NORTHERN MN WITH THE GFS KEEPING NORTH OF THE
INTERNATIONAL BORDER. BASED ON CURRENT TRENDS AND PERFORMANCE OF
THE MODELS WITH THE LAST STORM...WILL GO WITH A MIXTURE OF NAM/ECMWF
FOR SOLUTION. THE COLD FRONT WILL ENTER WESTERN LATE SATURDAY
MORNING AND ACROSS THE TWIN PORTS LATE SATURDAY EVENING.
THUNDERSTORMS WILL DEVELOP SATURDAY MORNING IN WRN MN AND MOVE EAST
DURING THE DAY. SPC DAY 3 OUTLOOK INDICATES A SLIGHT RISK MAINLY
EAST OF HIGHWAY 53/I-35 IN MN WITH MARGINAL RISK ACROSS MOST OF THE
REST OF THE FORECAST AREA. AS INDICATED BY THE MID SHIFT...THERE
WILL BE A RISK FOR SEVERE THUNDERSTORMS IN THE AFTERNOON BUT MAY BE
FOCUSED FURTHER WEST IN MN. IT STILL LOOKS LIKE A MCS MAY DEVELOP
LATER IN THE AFTERNOON. IT WILL BE ANOTHER HEAVY RAIN EVENT WITH
PWATS IN THE 1.5 TO 2.0 INCHES EXPECTED ACROSS THE FORECAST AREA.
STORM TOTAL QPF FORECAST IS FOR 1-1.5 INCHES FROM INL TO BRD WITH
0.50 TO 0.75 INCHES FURTHER EAST BY SUNDAY MORNING.
SIMILAR TO THE PAST SYSTEM...MUCH COOLER AIR WILL PUSH INTO THE
REGION WITH SOME SHOWERS ON SUNDAY. HIGHS WILL BE IN THE 60S INTO
THE MIDDLE OF THE WEEK WITH 45-55 AT NIGHT. A SHORTWAVE WILL PASS
THROUGH THE REGION ON THURSDAY BRINGING A POSSIBILITY OF A
THUNDERSTORM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1228 AM CDT FRI AUG 21 2015
SURFACE RIDGE OF HIGH PRESSURE SLIDING EAST ACROSS THE AREA
OVERNIGHT...WITH SOUTHWEST RETURN FLOW SETTING UP FOR TOMORROW.
MAINLY VFR CONDITIONS AT THIS TIME WITH LIGHT AND VARIABLE WINDS.
FOG HAS ALREADY DEVELOPED AT KHIB...AND EXPECT THIS TO SPREAD TO
ALL TERMINALS IN THE NEXT FEW HOURS. I EXPECT KHYR...KDLH AND KHIB
TO BE AFFECTED WITH IFR CONDITIONS AND CEILINGS THROUGH
APPROXIMATELY 12Z...WITH MVFR CONDITIONS AT KINL AND KBRD AS SOUTH
WINDS SHOULD INCREASE THERE AFTER 09Z AND HELP MIX OUT THE FOG.
FOG TO DISSIPATE IN THE 11-14Z TIME RANGE AND RETURN TO VFR
CONDITIONS FOR THE REMAINDER OF THE TAF PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 62 79 55 65 / 20 40 80 30
INL 60 80 53 63 / 20 70 80 60
BRD 64 81 54 65 / 20 70 60 30
HYR 62 81 55 67 / 10 10 70 30
ASX 61 84 57 69 / 10 10 80 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
UPDATE...LE
SHORT TERM...JJM
LONG TERM...STEWART
AVIATION...LE
AREA FORECAST DISCUSSION
NWS GLASGOW MT
947 AM MDT FRI AUG 21 2015
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY...
MORNING UPDATE...
CHANGE TO THE FORECAST FOR THIS MORNING WERE FOCUSED ON SPORADIC
QPF BLOTCHES WHICH ARE SHOWING UP IN VARIOUS MODELS IN DIFFERENT
PLACES ACROSS THE CWA. WITH THE STALLED FRONTAL BOUNDARY ISOLATED
RAIN SHOWERS WILL BE POSSIBLE BUT PLACEMENT FOR THESE SHOWERS IS
GENERALLY UNKNOWN. BEST GUESS WOULD BE FORMATIONS OVER THE
CENTRAL MONTANA MOUNTAINS WERE LIGHT RAIN SHOWERS WOULD THEN
WANDER IN TO THE WESTERN ZONES OF THE CWA... BUT THEN THE RAP AND
HRRR BOTH SHOW A SHOWER FORMING OVER THE BIG SHEEP HILLS. SO EVEN
EASTERN ZONES ARE NOT OUT OF THE QUESTION TO RECEIVE VERY LIGHT
PRECIP THIS AFTERNOON. WITH A SLIGHT REWORKING OF WIND GRIDS THIS
AFTERNOON ALSO SAW THE WINDS AHEAD OF THE FRONT FALLING OFF TO
LESS THAN 10 KTS AT TIMES. HOWEVER... DIRECTLY BEHIND THE FRONT
WINDS RAMP UP FAST AND STRONG. SO... HAVE NOT TOUCHED ANY OF THE
HAZARD PRODUCTS IN ANTICIPATION OF THE KICK UP OVERNIGHT. GAH
PREVIOUS SHORT TERM DISCUSSION...
UPPER LEVEL TROUGH CURRENTLY MOVING ACROSS BRITISH COLUMBIA WILL
MOVE ACROSS EASTERN MONTANA TONIGHT AND SATURDAY. TO THE EAST...
LOW PRESSURE SYSTEM WILL DEVELOP OVER EASTERN MONTANA TODAY AND
MOVE EAST INTO NORTH DAKOTA THIS EVENING. THIS WILL DRAG A COLD
FRONT ACROSS EASTERN MONTANA THIS AFTERNOON AND EARLY EVENING.
LOOK FOR VERY WARM TEMPERATURES AND LOW RH AHEAD OF THE FRONT
TODAY. WITH GUSTY WEST WINDS EXPECTED BEHIND THE FRONT IN THE WEST
THIS AFTERNOON... WILL KEEP RED FLAG WARNING IN EFFECT. SEE FIRE
WEATHER DISCUSSION FOR MORE INFORMATION. THE DRY AIR MASS WILL
ALSO BRING A DRY FRONTAL PASSAGE FOR THE MOST PART. UNSTABLE AIR
MASS IN THE EAST MAY ALLOW FOR A SLIGHT CHANCE OF THUNDERSTORMS
THIS AFTERNOON.
A TIGHT SURFACE GRADIENT WILL DEVELOP THIS EVENING BETWEEN THE
LOW PRESSURE SYSTEM IN NORTH DAKOTA AND A SURFACE HIGH IN
ALBERTA. THIS WILL ALLOW GUSTY NORTHWEST WINDS TO DEVELOP. WILL
ISSUE A LAKE WIND ADVISORY FOR FORT PECK LAKE STARTING AT 21Z (3
PM MDT). MOISTURE WITH THIS SYSTEM WILL BE PRIMARILY IN THE UPPER
TROUGH. WILL INCREASE THE CHANCES OF SHOWERS FROM WEST TO EAST
TONIGHT AS THE UPPER TROUGH MOVES INTO THE AREA. AIR MASS MAY BE
UNSTABLE ENOUGH FOR AN ISOLATED THUNDERSTORM THIS EVENING.
THE UPPER TROUGH MOVES INTO THE DAKOTAS SATURDAY AFTERNOON WHILE
THE SURFACE LOW MOVES INTO MINNESOTA. MOISTURE ASSOCIATED WITH
THE UPPER TROUGH WILL BRING RAIN SHOWERS TO MOST OF THE FORECAST
AREA DURING THE MORNING AND IN THE EAST IN THE AFTERNOON. TIGHT
SURFACE GRADIENT REMAINS SO IT WILL BE WINDY WITH NW WINDS 20 TO
35 MPH. MUCH COLDER AIR MASS WILL BE IN PLACE WITH HIGHS 55 TO 65
OR ABOUT 30 DEGREES COLDER THAN TODAY.
HIGH PRESSURE BUILDS INTO EASTERN MONTANA SATURDAY NIGHT
DIMINISHING THE WINDS AND CLEARING THE SKIES. WITH COLDER AIR MASS
IN PLACE...SOME AREAS WILL HAVE LOWS IN THE 30S.
HIGH PRESSURE REMAINS OVER EASTERN MONTANA ON SUNDAYS WITH MOSTLY
SUNNY SKIES AND WARMER TEMPERATURES. FORRESTER
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD BEGINS SUNDAY NIGHT WITH AN UPPER LEVEL RIDGE
IN PLACE OVER THE WEST. THE RIDGE AXIS WILL BE ALIGNED WITH THE
NORTHERN ROCKIES INITIALLY. THE AXIS MOVES OVER NORTHEAST MONTANA
AROUND MONDAY NIGHT...WHICH WILL ALLOW DESERT AIR TO CREEP NORTH
INTO THE LOCAL REGION. THIS WILL SEND TEMPERATURES ABOVE NORMAL
BEGINNING TUESDAY.
BY WEDNESDAY A SHORT-WAVE DISTURBANCE RIDES THE RIDGE NORTH INTO
WYOMING...UNDER-CUTTING MONTANA. MODELS SHOW SOME LOCAL INSTABILITY
DEVELOPING LATE WEDNESDAY INTO THURSDAY. THEN FRIDAY ANOTHER
EMBEDDED BUT WEAKER DISTURBANCE COULD CONTINUE THE CHANCE FOR
THUNDERSTORMS AND RAIN SHOWERS.
OVERALL...EXPECT INITIALLY NORMAL TEMPERATURES THAT INCREASE TO
ABOVE AVERAGE FOR THE MOST OF THE PERIOD. ALSO EXPECT DRY
CONDITIONS UNTIL MID-WEEK. SCT
&&
.AVIATION...
FLIGHT CATEGORY: VFR INITIALLY... MVFR/IFR BY THE END OF THE
CYCLE.
SYNOPSIS: A SURFACE TROUGH AND STALLED FRONT WILL BRING ABOUT
VEERING WIND SHIFTS. ISOLATED SHOWERS COULD ALSO FORM ON THESE
BOUNDARIES THIS AFTERNOON BUT CHANCE ARE TOO LOW TO INCLUDE IN
THE TAFS.
STORM SYSTEM: A COMPACT STORM SYSTEM WILL MOVE THROUGH THE REGION
TONIGHT BRINGING RAIN SHOWERS AND SOME THUNDERSTORMS...ALONG WITH
GUSTY NORTHWEST WIND. EXPECT CEILINGS AND VISIBILITY CONDITIONS
TO BECOME MVFR/IFR BY OR AFTER 12Z. CONDITIONS WILL BEGIN TO IMPROVE
SATURDAY NIGHT.
HAZE: CLOUDS WILL BE MIXED WITH SMOKE FROM WILD FIRES IN THE
WEST...PRODUCING A HAZY OVERCAST AT TIMES.
WINDS: FROM THE EAST AND SOUTHEAST AT LESS THAN 10 KTS THIS
MORNING... VEERING TO THE WEST THIS AFTERNOON AND INCREASING TO 10
TO 15 KTS.... THEN FURTHER VEERING TO THE NORTHWEST OVERNIGHT AND
INCREASING TO 20-30KT WHEN A STRONG COLD FRONT MOVES THROUGH THE
AREA.
GAH/SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM MDT SATURDAY
FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL
AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.
RED FLAG WARNING FROM NOON TODAY TO MIDNIGHT TONIGHT FOR FIRE
WEATHER ZONES 134...135...136...AND 137.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1001 AM PDT FRI AUG 21 2015
.SYNOPSIS...HAZY CONDITIONS WILL CONTINUE OVER THE NEXT FEW DAYS DUE
TO SMOKE PASSING THROUGH THE AREA FROM CALIFORNIA WILDFIRES. A WEAK
PUSH OF MOISTURE WILL LEAD TO SLIGHT CHANCES FOR THUNDERSTORMS OVER
MAINLY THE HIGHER TERRAIN SOUTH OF INTERSTATE 15 FRIDAY AND
SATURDAY. DEEPER MOISTURE ARRIVES MONDAY AND COULD LINGER THROUGH
MID WEEK WHICH WILL RESULT IN INCREASING COVERAGE OF SHOWERS AND
STORMS. &&
.UPDATE...EXTENSIVE AREA OF SMOKE/HAZE VISIBLE OFF SATELLITE
COVERING MUCH OF INYO COUNTY AND SOUTHERN NEVADA. VISIBILITY SHOULD
IMPROVE THROUGHOUT THE DAY DUE TO A DEEPER MIXED LAYER.
BASED ON THE HRRR AND 12Z NAM/GFS REMOVED MENTION OF THUNDERSTORMS
FROM THE HIGHER TERRAIN OF SOUTHERN NEVADA AND MUCH OF MOHAVE COUNTY
TODAY. LEFT SLIGHT CHANCE MENTION FOR THE FAR NORTHEAST CORNER OF
MOHAVE COUNTY.
&&
.PREV DISCUSSION...150 AM PDT FRI AUG 21 2015
.SHORT TERM...THROUGH MONDAY NIGHT.
CLEAR SKIES DOMINATE THE FORECAST AREA EARLY THIS MORNING BUT THICK
SMOKE CONTINUES TO BE PROBLEMATIC ACROSS THE OWENS VALLEY. I
ANTICIPATE THE SMOKE WILL CONTINUE TO BE PREVAIL ACROSS THE OWENS
VALLEY AGAIN TODAY...ESPECIALLY FROM BISHOP SOUTHWARD TO OLANCHA.
ELSEWHERE...HAZE REMAINS POSSIBLE AS SMOKE FROM CALIFORNIA WILDFIRES
DRIFTS WEST...THROUGH AFTERNOON BREEZY CONDITIONS MAY HELP MIX OUT
THE HAZE AS IT DID THURSDAY...IMPROVING THE AIR QUALITY SOMEWHAT.
THE BIGGEST CONCERN IN THE SHORT TERM PERIOD BESIDES THE SMOKE
REVOLVES AROUND THUNDERSTORM CHANCES. MOISTURE HAS BEEN SEEPING
INTO THE AREA UNDER A SOUTHERLY FLOW IN THE LOWER LEVELS OF THE
ATMOSPHERE. DEWPOINTS EARLY THIS MORNING HAVE REACHED NEAR 60
DEGREES AT BULLHEAD CITY AND NEEDLES...AND MID 60S IN LAKE HAVASU.
FURTHER SOUTH...THE DEWPOINT IN YUMA HAS SHOT UP TO 75F AND VAD WIND
PROFILER DATA INDICATES A SOUTHERLY FLOW OF 15-20KTS IN THE LOWER 4K
FEET OF THE ATMOSPHERE DRIVING THIS DEEPER MOISTURE NORTHWARD. WHILE
MUCH OF THIS MOISTURE WILL MIX OUT WITH DAYTIME HEATING...THERE
SHOULD STILL BE ENOUGH MOISTURE TO KICK OFF SOME ISOLATED CONVECTION
ALONG THE HIGHER TERRAIN OF MOHAVE...EXTREME EASTERN SAN
BERNARDINO...AND SOUTHERN CLARK COUNTIES THIS AFTERNOON AND EVENING.
TROUBLE WILL BE THE LACK OF ANY SUBSTANCIAL TRIGGERING MECHANISM TO
GET THINGS GOING. EARLY MORNING RUNS OF THE HRRR DO NOT PAINT A VERY
PROMISING PICTURE FOR STORMS TODAY AND MOST MODEL GUIDANCE DOESNT
DEVELOP ACTIVITY DESPITE THE INSTABILITY PRESENT. OPTED TO MAINTAIN
THE SLIGHT CHANCE...TERRAIN ORIENTED POPS BUT CONFIDENCE IN
DEVELOPMENT IS NOT REAL HIGH. SIMILAR OUTLOOK FOR SATURDAY WITH
MARGINAL MOISTURE AND INSABILITY PRESENT...BUT NO REAL TRIGGER.
ON SUNDAY...ANY DISCERNIBLE INSTABILITY GETS SHIFTED FURTHER EAST
INTO FAR EASTERN MOHAVE COUNTY...SO KEPT POPS LIMITED TO THOSE FAR
EASTERN ZONES AND CONDITIONS DRY ELSEWHERE. TEMPERATURES FRIDAY
THROUGH THE WEEKEND WILL AVERAGE 3 TO 6 DEGREES ABOVE NORMAL.
ON MONDAY...LEADING EDGE OF DEEPER MONSOON MOISTURE BEGINS TO LIFT
INTO NORTHWEST ARIZONA AND EASTERN CALIFORNIA. BETTER MOISTURE AT
THIS POINT LOOKS TO ARRIVE OVERNIGHT AND INTO TUESDAY BUT SOME
ACTIVITY MAY BREAK OUT IN MOHAVE...EASTERN SAN BERNARDINO...AND THE
HIGHER TERRAIN OF CLARK COUNTIES AND MAINTAINED POPS IN THESE AREAS.
.LONG TERM...TUESDAY THROUGH FRIDAY.
MODELS HAVE COME INTO BETTER LARGE SCALE AGREEMENT FOR MUCH OF THE
PERIOD...BUT IMPORTANT DETAIL DIFFERENCES REMAIN. FOR TUESDAY...THE
GFS LOOKS MUCH LIKE ITS PREVIOUS RUNS...BUT THE ECMWF DEPICTS THE
FOUR CORNERS HIGH CENTER JUST A BIT FARTHER WEST...WHICH DELAYS THE
MOISTURE RETURN AND SENDS HIGH TEMPERATURES ZOOMING BACK UP TO NEAR
EXCESSIVE HEAT CRITERIA. WHILE THIS IS A POSSIBILITY...BELIEVE IT
HAS A LOW PROBABILITY OF OCCURRENCE GIVEN MODEL TRENDS OVER THE PAST
SEVERAL DAYS...AND HAVE GIVEN IT LITTLE WEIGHT IN THE FORECAST. THE
GFS SOLUTION...WHICH SUGGESTS PRECIP CHANCES ROUGHLY NEAR AND EAST
OF LAS VEGAS...WAS PREFERRED. FOR WEDNESDAY AND THURSDAY...MODELS
HAVE COME INTO MUCH BETTER AGREEMENT WITH AMPLIFICATION OF BOTH THE
NORTHERN STREAM LOW NEAR THE BRITISH COLUMBIA COAST AND THE RIDGE
EXTENDING NORTH INTO SASKATCHEWAN FROM THE FOUR CORNERS HIGH. THIS
LEAVES OUR CWA IN MOIST SOUTHERLY FLOW ON WEDNESDAY...TRANSITIONING
INTO A SLIGHTLY DRIER SOUTHWEST FLOW ON THURSDAY AS TROUGHING IN THE
EAST PACIFIC STRETCHES ALL THE WAY DOWN BELOW 30N. THERE IS
DISAGREEMENT ON HOW TO EVOLVE THIS TROUGHING ON FRIDAY...BUT DECENT
CONSENSUS THAT OUR SENSIBLE WEATHER WILL CHANGE LITTLE...WITH
SOUTHWEST FLOW BRINGING MINIMAL PRECIP CHANCES BUT PERHAPS NOT
STRONG ENOUGH TO SCOUR OUT LOW LEVEL MOISTURE...ESPECIALLY OVER
MOHAVE COUNTY.
&&
.AVIATION...FOR MCCARRAN...LIGHT SOUTHERLY DRAINAGE WINDS EXPECTED
EARLY IN THE MORNING BEFORE BECOMING LIGHT AND VARIABLE SUNRISE
THROUGH AROUND 17Z. A PERIOD OF SOUTHEAST WINDS OF 9-12KTS IS
POSSIBLE BETWEEN 17Z AND 20Z BEFORE SOUTH-SOUTHWEST WINDS TAKE OVER
IN THE AFTERNOON WITH GUSTS TO 25KTS. HAZY CONDITIONS REMAIN
POSSIBLE.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...AREAS OF HAZE EXPECTED MAINLY NORTH OF INTERSTATE 40
AGAIN TODAY WITH SMOKE MOST CONCENTRATED NEAR THE SIERRA AND OWENS
VALLEY. SMOKE MAY LOCALLY REDUCE VISIBILITIES TO BELOW 4 MILES.
OTHERWISE...BREEZY SOUTH WINDS OF 12-18 KTS WITH GUSTS TO 25KTS
EXPECTED ACROSS THE AREA IN THE AFTERNOON. SLIGHT CHANCES FOR
ISOLATED THUNDERSTORMS EXIST IN THE HIGHER TERRAIN MAINLY SOUTH AND
EAST OF KLAS THIS AFTERNOON.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE...PIERCE
SHORT TERM...OUTLER
LONG TERM...MORGAN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
150 AM PDT FRI AUG 21 2015
.SYNOPSIS...HAZY CONDITIONS WILL CONTINUE OVER THE NEXT FEW DAYS DUE
TO SMOKE PASSING THROUGH THE AREA FROM CALIFORNIA WILDFIRES. A WEAK
PUSH OF MOISTURE WILL LEAD TO SLIGHT CHANCES FOR THUNDERSTORMS OVER
MAINLY THE HIGHER TERRAIN SOUTH OF INTERSTATE 15 FRIDAY AND
SATURDAY. DEEPER MOISTURE ARRIVES MONDAY AND COULD LINGER THROUGH
MID WEEK WHICH WILL RESULT IN INCREASING COVERAGE OF SHOWERS AND
STORMS. &&
.SHORT TERM...THROUGH MONDAY NIGHT.
CLEAR SKIES DOMINATE THE FORECAST AREA EARLY THIS MORNING BUT THICK
SMOKE CONTINUES TO BE PROBLEMATIC ACROSS THE OWENS VALLEY. I
ANTICIPATE THE SMOKE WILL CONTINUE TO BE PREVAIL ACROSS THE OWENS
VALLEY AGAIN TODAY...ESPECIALLY FROM BISHOP SOUTHWARD TO OLANCHA.
ELSEWHERE...HAZE REMAINS POSSIBLE AS SMOKE FROM CALIFORNIA WILDFIRES
DRIFTS WEST...THROUGH AFTERNOON BREEZY CONDITIONS MAY HELP MIX OUT
THE HAZE AS IT DID THURSDAY...IMPROVING THE AIR QUALITY SOMEWHAT.
THE BIGGEST CONCERN IN THE SHORT TERM PERIOD BESIDES THE SMOKE
REVOLVES AROUND THUNDERSTORM CHANCES. MOISTURE HAS BEEN SEEPING
INTO THE AREA UNDER A SOUTHERLY FLOW IN THE LOWER LEVELS OF THE
ATMOSPHERE. DEWPOINTS EARLY THIS MORNING HAVE REACHED NEAR 60
DEGREES AT BULLHEAD CITY AND NEEDLES...AND MID 60S IN LAKE HAVASU.
FURTHER SOUTH...THE DEWPOINT IN YUMA HAS SHOT UP TO 75F AND VAD WIND
PROFILER DATA INDICATES A SOUTHERLY FLOW OF 15-20KTS IN THE LOWER 4K
FEET OF THE ATMOSPHERE DRIVING THIS DEEPER MOISTURE NORTHWARD. WHILE
MUCH OF THIS MOISTURE WILL MIX OUT WITH DAYTIME HEATING...THERE
SHOULD STILL BE ENOUGH MOISTURE TO KICK OFF SOME ISOLATED CONVECTION
ALONG THE HIGHER TERRAIN OF MOHAVE...EXTREME EASTERN SAN
BERNARDINO...AND SOUTHERN CLARK COUNTIES THIS AFTERNOON AND EVENING.
TROUBLE WILL BE THE LACK OF ANY SUBSTANCIAL TRIGGERING MECHANISM TO
GET THINGS GOING. EARLY MORNING RUNS OF THE HRRR DO NOT PAINT A VERY
PROMISING PICTURE FOR STORMS TODAY AND MOST MODEL GUIDANCE DOESNT
DEVELOP ACTIVITY DESPITE THE INSTABILITY PRESENT. OPTED TO MAINTAIN
THE SLIGHT CHANCE...TERRAIN ORIENTED POPS BUT CONFIDENCE IN
DEVELOPMENT IS NOT REAL HIGH. SIMILAR OUTLOOK FOR SATURDAY WITH
MARGINAL MOISTURE AND INSABILITY PRESENT...BUT NO REAL TRIGGER.
ON SUNDAY...ANY DISCERNIBLE INSTABILITY GETS SHIFTED FURTHER EAST
INTO FAR EASTERN MOHAVE COUNTY...SO KEPT POPS LIMITED TO THOSE FAR
EASTERN ZONES AND CONDITIONS DRY ELSEWHERE. TEMPERATURES FRIDAY
THROUGH THE WEEKEND WILL AVERAGE 3 TO 6 DEGREES ABOVE NORMAL.
ON MONDAY...LEADING EDGE OF DEEPER MONSOON MOISTURE BEGINS TO LIFT
INTO NORTHWEST ARIZONA AND EASTERN CALIFORNIA. BETTER MOISTURE AT
THIS POINT LOOKS TO ARRIVE OVERNIGHT AND INTO TUESDAY BUT SOME
ACTIVITY MAY BREAK OUT IN MOHAVE...EASTERN SAN BERNARDINO...AND THE
HIGHER TERRAIN OF CLARK COUNTIES AND MAINTAINED POPS IN THESE AREAS.
.LONG TERM...TUESDAY THROUGH FRIDAY.
MODELS HAVE COME INTO BETTER LARGE SCALE AGREEMENT FOR MUCH OF THE
PERIOD...BUT IMPORTANT DETAIL DIFFERENCES REMAIN. FOR TUESDAY...THE
GFS LOOKS MUCH LIKE ITS PREVIOUS RUNS...BUT THE ECMWF DEPICTS THE
FOUR CORNERS HIGH CENTER JUST A BIT FARTHER WEST...WHICH DELAYS THE
MOISTURE RETURN AND SENDS HIGH TEMPERATURES ZOOMING BACK UP TO NEAR
EXCESSIVE HEAT CRITERIA. WHILE THIS IS A POSSIBILITY...BELIEVE IT
HAS A LOW PROBABILITY OF OCCURRENCE GIVEN MODEL TRENDS OVER THE PAST
SEVERAL DAYS...AND HAVE GIVEN IT LITTLE WEIGHT IN THE FORECAST. THE
GFS SOLUTION...WHICH SUGGESTS PRECIP CHANCES ROUGHLY NEAR AND EAST
OF LAS VEGAS...WAS PREFERRED. FOR WEDNESDAY AND THURSDAY...MODELS
HAVE COME INTO MUCH BETTER AGREEMENT WITH AMPLIFICATION OF BOTH THE
NORTHERN STREAM LOW NEAR THE BRITISH COLUMBIA COAST AND THE RIDGE
EXTENDING NORTH INTO SASKATCHEWAN FROM THE FOUR CORNERS HIGH. THIS
LEAVES OUR CWA IN MOIST SOUTHERLY FLOW ON WEDNESDAY...TRANSITIONING
INTO A SLIGHTLY DRIER SOUTHWEST FLOW ON THURSDAY AS TROUGHING IN THE
EAST PACIFIC STRETCHES ALL THE WAY DOWN BELOW 30N. THERE IS
DISAGREEMENT ON HOW TO EVOLVE THIS TROUGHING ON FRIDAY...BUT DECENT
CONSENSUS THAT OUR SENSIBLE WEATHER WILL CHANGE LITTLE...WITH
SOUTHWEST FLOW BRINGING MINIMAL PRECIP CHANCES BUT PERHAPS NOT
STRONG ENOUGH TO SCOUR OUT LOW LEVEL MOISTURE...ESPECIALLY OVER
MOHAVE COUNTY.
&&
.AVIATION...FOR MCCARRAN...LIGHT SOUTHERLY DRAINAGE WINDS EXPECTED
EARLY IN THE MORNING BEFORE BECOMING LIGHT AND VARIABLE SUNRISE
THROUGH AROUND 17Z. A PERIOD OF SOUTHEAST WINDS OF 9-12KTS IS
POSSIBLE BETWEEN 17Z AND 20Z BEFORE SOUTH-SOUTHWEST WINDS TAKE OVER
IN THE AFTERNOON WITH GUSTS TO 25KTS. HAZY CONDITIONS REMAIN
POSSIBLE.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...AREAS OF HAZE EXPECTED MAINLY NORTH OF INTERSTATE 40
AGAIN TODAY WITH SMOKE MOST CONCENTRATED NEAR THE SIERRA AND OWENS
VALLEY. SMOKE MAY LOCALLY REDUCE VISIBILITIES TO BELOW 4 MILES.
OTHERWISE...BREEZY SOUTH WINDS OF 12-18 KTS WITH GUSTS TO 25KTS
EXPECTED ACROSS THE AREA IN THE AFTERNOON. SLIGHT CHANCES FOR
ISOLATED THUNDERSTORMS EXIST IN THE HIGHER TERRAIN MAINLY SOUTH AND
EAST OF KLAS THIS AFTERNOON.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM...OUTLER
LONG TERM...MORGAN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
331 PM MDT FRI AUG 21 2015
.SYNOPSIS...
HIGH PRESSURE ALOFT WILL GRADUALLY BUILD OVER THE AREA THROUGH
SATURDAY WITH DAYTIME TEMPERATURES REMAINING ABOVE NORMALS. BEST
THUNDERSTORM COVERAGE WILL REMAIN FOCUSED OVER THE HIGHER TERRAIN
AND SOUTHWEST SATURDAY AFTERNOON AND EVENING. THEREAFTER...ANOTHER
SEASONABLY STRONG BACKDOOR FRONT WILL BOOST STORM COVERAGE ON
SUNDAY ESPECIALLY FOR THE WESTERN AND SOUTHERN HALVES OF THE
STATE. DAYTIME TEMPERATURES WILL DOWNWARD AGAIN...ESPECIALLY
ACROSS THE EASTERN PLAINS WHERE HIGH TEMPERATURES ARE FORECAST TO
BE BELOW NORMAL AND A GOOD 15 TO 25 DEGREES COOLER AS COMPARED TO
SATURDAY. LOOKING AHEAD...AFTER A RELATIVELY ACTIVE DAY ON MONDAY
A GRADUAL WARMING AND DRYING TREND WILL DOMINATE MUCH OF NEXT WEEK
WITH STORM COVERAGE WANING EACH DAY THROUGH WEEK/S END.
&&
.DISCUSSION...
SUBTLE WAVE ALOFT/ASSOCIATED JET MAX TO TRANSLATE EAST OF THE
AREA BY EARLY EVENING. LOOKS TO BE VISUAL EVIDENCE OF SUBSIDENCE
EFFECTS IN THE IMMEDIATE FOUR CORNERS REGION. WILL NEED TO
CAREFULLY MONITOR THE FAR NE...EC/SE PLAINS NEXT SEVERAL HOURS.
A FAIRLY ATYPICAL SURFACE DRYLINE IN THE PROCESS OF SHARPENING
EAST OF DES MOINES TO SANTA ROSA TO FORT SUMNER LINE /SFC DEW
POINTS IN THE MID 20S TO MID 30S WEST OF THE DRYLINE WHILE MID 50S
TO NEAR 60 COMMON TO THE EAST/ WITH A MORE DIFFUSE W-E GRADIENT
OVER THE SOUTHEAST PLAINS. THIS BOUNDARY WILL LIKELY FOCUS A FEW
STRONG IF NOT BRIEFLY SEVERE STORMS LATER THIS AFTERNOON INTO
EARLY EVENING.
OTHERWISE...BETTER MOISTURE PROFILES CONTINUE OVER SC/SW ZONES
WHERE WE/LL CONTINUE TO FOCUS THE HIGHEST POPS. STORM MOTIONS
GENERALLY TOWARD THE SE AT 15-20 KTS...AND COULD SEE A FEW PULSE
STRONG STORMS WITH LOCALIZED GUSTY WINDS AND OF COURSE CG
LIGHTNING THE MAIN THREATS.
CONCEPTUAL MODEL WOULD ARGUE FOR A PRETTY QUIET PERIOD AFTER
MIDNIGHT AS 500MB HEIGHTS SLOWLY BUILD FROM SW TO NE. BUT THE
GFS/NAM AND NOT SURPRISINGLY HRRR REDEVELOP VERY ISOLATED QPF
OVER THE WEST ESPECIALLY NORTHWEST. THIS MAY BE IN RESPONSE TO YET
ANOTHER SPEED MAX WITHIN THE BASE OF YET ANOTHER VIGOROUS
SHORTWAVE TROUGH THAT WILL CROSS THE CENTRAL/NORTHERN ROCKIES LATE
TONIGHT. BEST GUESS IS WE COULD SEE SOME MID-LEVEL CLOUDINESS AND
VIRGA SHOWERS/SPRINKLES DURING THE OVERNIGHT BUT HIGHLY DOUBT WE
WOULD SEE A REPEAT OF EARLY MORNING T-STORMS.
GOING INTO SATURDAY NIGHT AND SUNDAY...FOCUS WILL BE ON THE
INCOMING BACKDOOR COLD FRONT THAT WILL FOLLOW IN WAKE OF THE ABOVE
MENTIONED SHORTWAVE. TIMING OF THE FRONT SIMILAR TO PREVIOUS
THINKING...INTO THE NORTHEAST SATURDAY EVENING PRESSING SOUTH AND
WEST OVERNIGHT SATURDAY NIGHT INTO MIDDAY SUNDAY. LOOKS PRETTY
COOL/STABLE ONCE AGAIN FOR THE NORTHEAST PLAINS...WITH THE FOCUS
FOR CONVECTIVE PRECIP SHIFTING WEST AND SOUTH. THE MODELS HONESTLY
LOOK A LITTLE UNDERCOOKED ON QPF FOR SUNDAY PM ESPECIALLY FOR
AREAS BETWEEN THE DIVIDE AND EAST SLOPES OF THE CENTRAL MOUNTAIN
CHAIN BUT THE CURRENT AIR MASS HAS NOT FULLY RECOVERED FROM THE
LAST DRYING EVENT AND NOT A TREMENDOUSLY MOIST AIR MASS BEING
USHERED IN WITH THIS FRONT. WILL SHOW AN UPWARD TREND IN POP
COVERAGE FOR SUNDAY...BUT GENERALLY NOT AS DRY AT THE NAM WOULD
SUGGEST.
WARMER ON MONDAY AND WITH ANY ADDITIONAL MOISTURE INPUT
ASSOCIATED WITH THE BACKDOOR PUSH WE EXPECT A DECENT INCREASE IN
T-STORM ACTIVITY. 500MB HIGH CENTER GENERALLY EXPECTED OVER THE
FOUR CORNERS OR PERHAPS A BIT EAST. STEERING WINDS WILL BE WEAK
BUT GENERALLY FROM N TO S...SO NOT ALL BAD NEWS FOR THE RIO GRANDE
VALLEY...NE AND CENTRAL HIGH PLAINS. RIDGE ALOFT FORECAST TO
STRENGTHEN TUE INTO MID-WEEK BEFORE SHIFTING WESTWARD LATE WEEK.
PROBABLY ANOTHER BACKDOOR COLD FRONT IN OUR FUTURE LATE THU OR
FRI. KJ
&&
.FIRE WEATHER...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WITH WETTING RAIN
WILL CONTINUE DEVELOPING THROUGHOUT THE AFTERNOON INTO THE EVENING
ACROSS THE SOUTHWEST....SOUTH CENTRAL AND NORTHERN MOUNTAINS AND
PORTIONS OF THE FAR EASTERN PLAINS. GUSTY AND ERRATIC WINDS WILL
FOLLOW STORMS THAT PRODUCE OUTFLOW BOUNDARIES.
SATURDAY WILL SEE ISOLATED TO SCATTERED STORMS FAVORING HIGH TERRAIN
AREAS...WITH ABOVE NORMAL TEMPERATURES...HIGHER MIN RH VALUES IN THE
SOUTHWEST MOUNTAINS WITH 5 HAINES VALUES ACROSS THE NORTHEAST AND
EAST CENTRAL PLAINS. EXPECT BREEZY TO MODERATE WEST NORTHWEST WINDS
DURING THE DAY.
LATE SATURDAY INTO EARLY SUNDAY...A POTENT BACK DOOR FRONT WILL
INVADE THE NORTHEAST...COOLING TEMPERATURES 5 TO 15 DEGREES BELOW
NORMAL CENTRAL AND EAST WHILE WETTING RAIN CHANCES AND MIN RH VALUES
TREND UPWARD CENTRAL AND WEST. EAST CANYON WINDS COULD PEAK 35 TO 45
MPH EARLY SUNDAY ALONG THE CENTRAL MOUNTAINS AS THE BACK DOOR FRONT
PUSHES THROUGH THE GAPS TOWARD THE CONTINENTAL DIVIDE. BREEZY TO
MODERATE EAST WINDS WILL CONTINUE THROUGHOUT THE DAY...BECOMING
SOUTHEASTERLY BY THE LATE AFTERNOON...EARLY EVENING AS THE FRONT
WASHES OUT.
SO FAR...MODELS LOOK TO AGREE WITH A VERY ACTIVE MONDAY AS THE GFS
HAS THE UPPER LEVEL HIGH OVER THE STATE WITH STORMS FAVORING CENTRAL
AND WESTERN AREAS WHILE THE ECMWF HAS THE HIGH OVER THE GREAT BASIN
AND IS MORE BULLISH FOR ACTIVITY TO FAVOR CENTRAL AND EASTERN AREAS.
BY TUESDAY...GFS HAS THE HIGH LINGERING OVER THE STATE WHILE THE
ECMWF HAS THE HIGH HOVERING OVER THE FOUR CORNERS REGION.
OTHERWISE...TEMPERATURES LOOK TO REBOUND MONDAY AND TUESDAY IN THE
EAST BECOMING ABOVE NORMAL BY THE MIDWEEK.
GOOD TO EXCELLENT VENT RATES TODAY AND SATURDAY. BECOMING POOR
CENTRAL AND NORTH SUNDAY...IMPROVING IN THE EAST MONDAY THROUGH
WEDNESDAY. 32
&&
.AVIATION...
18Z TAF CYCLE
SCT CIGS CURRENTLY DEVELOPING ACROSS MUCH OF WESTERN AND CENTRAL
NEW MEXICO. LOOK FOR SHRA/TSRA ACTIVITY TO FAVOR THE
SOUTHWEST...NORTHERN AND SOUTH CENTRAL MTNS THIS AFTERNOON. HAD
LOW CONFIDENCE OF VCTS...SO KEPT VCSH FOR KABQ/KAEG...KSAF AND
KROW. EXPECT BREEZY TO MODERATE NORTHWEST WINDS BETWEEN 19 AND 00Z
ACROSS WESTERN AND CENTRAL AREAS. COULD SEE STORM CHANCES CONTINUE
AFTER SUNSET ACROSS THE SOUTHWEST MTNS AND THE FAR EASTERN PLAINS.
CML
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 60 91 59 90 / 10 5 10 10
DULCE........................... 48 85 49 84 / 10 10 10 20
CUBA............................ 53 82 53 80 / 10 20 10 20
GALLUP.......................... 55 86 54 86 / 30 20 20 30
EL MORRO........................ 52 82 51 80 / 30 20 20 50
GRANTS.......................... 55 84 53 80 / 30 20 20 20
QUEMADO......................... 56 82 54 80 / 30 30 30 40
GLENWOOD........................ 58 85 58 85 / 30 30 30 60
CHAMA........................... 47 79 47 77 / 10 40 20 30
LOS ALAMOS...................... 59 84 57 79 / 10 30 30 40
PECOS........................... 57 83 56 75 / 10 20 20 40
CERRO/QUESTA.................... 51 80 50 77 / 10 20 10 30
RED RIVER....................... 43 69 44 65 / 10 40 20 60
ANGEL FIRE...................... 46 72 46 67 / 10 20 30 40
TAOS............................ 46 84 50 78 / 10 20 10 20
MORA............................ 53 80 51 71 / 10 20 20 40
ESPANOLA........................ 57 89 56 84 / 10 10 10 10
SANTA FE........................ 60 85 58 79 / 10 20 10 20
SANTA FE AIRPORT................ 58 88 57 82 / 10 10 10 10
ALBUQUERQUE FOOTHILLS........... 64 90 63 84 / 20 10 10 10
ALBUQUERQUE HEIGHTS............. 67 92 64 86 / 20 10 10 10
ALBUQUERQUE VALLEY.............. 62 93 62 88 / 20 10 10 10
ALBUQUERQUE WEST MESA........... 65 94 63 88 / 10 10 10 10
LOS LUNAS....................... 64 93 62 87 / 20 10 10 10
RIO RANCHO...................... 65 93 63 87 / 10 10 10 10
SOCORRO......................... 66 94 63 89 / 20 10 20 10
SANDIA PARK/CEDAR CREST......... 58 86 57 79 / 20 20 10 20
TIJERAS......................... 57 88 56 80 / 20 10 10 10
MORIARTY/ESTANCIA............... 54 88 53 79 / 10 10 10 20
CLINES CORNERS.................. 58 85 54 75 / 10 10 10 20
GRAN QUIVIRA.................... 60 86 59 79 / 20 10 10 30
CARRIZOZO....................... 63 90 62 81 / 20 10 20 20
RUIDOSO......................... 60 82 56 74 / 20 30 30 30
CAPULIN......................... 57 84 53 73 / 10 20 30 10
RATON........................... 54 89 52 79 / 10 20 20 20
SPRINGER........................ 54 90 54 78 / 10 20 20 20
LAS VEGAS....................... 55 87 52 74 / 10 20 10 20
CLAYTON......................... 62 93 57 76 / 10 10 20 10
ROY............................. 59 90 56 73 / 10 20 20 10
CONCHAS......................... 64 96 61 78 / 10 10 20 10
SANTA ROSA...................... 62 95 61 79 / 10 10 20 10
TUCUMCARI....................... 65 98 63 79 / 10 10 20 10
CLOVIS.......................... 64 96 62 80 / 20 10 20 20
PORTALES........................ 65 96 64 81 / 20 10 20 20
FORT SUMNER..................... 66 97 64 79 / 10 10 20 10
ROSWELL......................... 68 101 67 86 / 20 10 20 30
PICACHO......................... 64 93 63 80 / 20 20 20 20
ELK............................. 63 86 61 76 / 20 20 20 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
41
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
601 PM EDT FRI AUG 21 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTHWARD FROM THE EASTERN GREAT LAKES
THIS WEEKEND BRINGING DRIER WEATHER. ANOTHER COLD FRONT WILL
APPROACH FROM THE WEST TUESDAY WITH SCATTERED SHOWERS AND STORMS
RETURNING TO THE FORECAST. FRONT STALLS IN THE AREA DURING THE
MIDDLE OF THE WEAK AND SLOWLY DISSIPATES. DRIER AIR MAY MOVE INTO
THE AREA FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 530 PM FRIDAY...THIS UPDATE WAS CONCERNED WITH THE
INCREASED DEVELOPMENT OF CONVECTION ACROSS THE FA. MAINLY ITS A
RESULT OF THE INTERACTION BETWEEN THE SEA BREEZE DRIFTING
INLAND... AND THE COOL FRONT DROPPING/DRIFTING SE-WARD. HAVE A
WIDE RANGE OF POPS ACROSS THE FA...MUCH OF IT ASSOCIATED WITH THE
LATEST 88D TRENDS IN REGARD TO LATEST CONVECTIVE DEVELOPMENT AND
MOVEMENT. HAVE ALSO UPPED QPF DUE TO WHAT THE LATEST 88DS ARE
SPITTING OUT... AND ESPECIALLY WITH CURRENT AND PROGGED 2.00 THRU
2.25 INCH PRECIPITABLE WATER RANGES.
PREVIOUS........................................................
AS OF 3 PM FRIDAY... THE COLD FRONT REMAINS TOUGH TO PICK OUT BUT
BASED ON THE LATEST OBS INCLUDING WINDS AND DEWPOINT DEPRESSIONS
IT APPEARS THAT THE FRONT IS BISECTING THE CWA FROM NE TO SW. IT
APPEARS TO BE MERGING WITH THE SEA BREEZE FRONT OVER OUR NC
COUNTIES...WHICH FURTHER COMPLICATES LOCATING THE COLD FRONT.
CONVECTION HAS FINALLY COMMENCED WITH ISOLATED SHOWERS FORMING IN
THE VICINITY OF THE COLD FRONT/SEA BREEZE FRONT CONGLOMERATION.
EXPECT THAT THIS FRONTAL FEATURE WILL CONTINUE TO BE THE FOCUS FOR
SCATTERED CONVECTION FOR THE REMAINDER OF THE AFTERNOON AND INTO
THE EVENING HOURS...WITH ACTIVITY SHUTTING DOWN BY AROUND MIDNIGHT
AS THIS IS ALL PRIMARILY DIURNALLY DRIVEN.
A CONSENSUS OF GUIDANCE GIVES US A NORTH TO SOUTH TEMPERATURE
GRADIENT...WITH LOWER 70S UP NORTH AND MID 70S TO THE SOUTH...AND
ALSO MID 70S AT THE COAST.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...REMAINS OF WEAK FRONT OFF THE NC COAST AT THE
START OF THE PERIOD WILL EXTEND WEST ACROSS NORTHERN SC. ALTHOUGH
THE FRONT WILL BECOME QUITE DIFFUSE BY MIDDAY STILL THINK PRECIP
CHANCES WILL REMAIN ELEVATED ACROSS PORTIONS OF SC. HIGH PRESSURE
BUILDING IN FROM THE NORTH HELPS KEEP PRESSURE GRADIENT
WEAK...WITH WEAK SEA BREEZE DEVELOPMENT IN THE AFTERNOON MASKING
THE FRONT. MOISTURE POOLING ALONG THE FRONT COUPLED WITH DIURNAL
HEATING IS LIKELY TO LEAD TO DEVELOPMENT OF AFTERNOON SHOWERS AND
THUNDERSTORMS. HAVE MAINTAINED INHERITED CHC TO SLIGHT CHC POP
ACROSS ILM SC COUNTIES. PRECIP SHOULD BE WEAKER AND DIURNAL IN
NATURE SO ONCE SUN SETS DEBRIS CLOUD WILL LINGER BUT PRECIP
COVERAGE SHOULD RAPIDLY DECREASE. TEMPERATURES SAT AND SAT NIGHT
WILL BE NEAR CLIMO.
WEAK SURFACE RIDGING REMAINS OVER THE EAST COAST SUN WITH MID
LEVEL FLOW ALOFT BECOMING PROGRESSIVE. WEAK SHORTWAVE MOVES ACROSS
THE SOUTHEAST LATER IN THE DAY...ACCOMPANIED BY AN INCREASED IN
MID LEVEL MOISTURE. THE CORE OF THE SHORTWAVE PASSES SOUTH OF THE
FORECAST AREA BUT PVA AHEAD OF IT COULD GENERATE SOME LATE
AFTERNOON/EVENING CONVECTION ACROSS MAINLY THE SC COUNTIES. WILL
CARRY AFTERNOON EVENING SLIGHT CHC/CHC POP TO COVER THE PASSAGE OF
THE WAVE. DEPENDING ON THE SPEED OF THE WAVE CONVECTION COULD
LINGER INTO THE OVERNIGHT PERIOD...BUT WEAK SUBSIDENCE FOLLOWING
THE SHORTWAVE SHOULD END ANY CONVECTION BY DAY BREAK. TEMPERATURES
WILL REMAIN NEAR CLIMO SUN AND SUN NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 330 PM FRIDAY...SHORTWAVE WILL PUSH A COLD FRONT INTO THE
CAROLINAS BUT IT LOOKS LIKE THIS FRONT WILL BECOME WASHED OUT AND
LINGER JUST SOUTH OR OVER THE COASTAL CAROLINAS. A MID TO UPPER
TROUGH DIGGING DOWN FROM THE GREAT LAKES WILL ALIGN WITH THIS
SHORTWAVE LEAVING A DEEP TROUGH DOWN THE EAST COAST THROUGH MUCH
OF THE UPCOMING WEEK. THE WINDS VEER AROUND TO THE NORTH
ALOFT...BUT OVERALL REMAIN QUITE LIGHT AND VARIABLE WITHOUT MUCH
OF A DRIVING FORCE TO THE FRONT. EXPECT GREATEST CHC OF PCP
FARTHER INLAND ON MON AFTN AND SHOULD PUSH TOWARD THE COAST ON
TUES. THIS BOUNDARY ALONG WITH LOCALIZED CONVERGENCE ALONG SEA
BREEZE AND PIEDMONT TROUGH FURTHER INLAND WILL CONTRIBUTE TO
DIURNAL CU DEVELOPMENT AND CONVECTIVE ACTIVITY. THE MODELS ARE NOT
GENERATING TOO MUCH IN THE WAY OF QPF AND DO NOT EXPECT CONVECTION
TO BE TOO WIDESPREAD...BUT LOCALIZED HEAVIER AMT ARE LIKELY IN
STRONGER STORMS. ANOTHER SHORTWAVE WILL ROTATE AROUND MAIN TROUGH
AND SHOULD ADVECT DRIER AIR IN FROM THE NORTHWEST BY THURS INTO
FRI. PCP WATER VALUES UP CLOSER TO 1.75 INCHES WILL FALL DOWN
BELOW 1.5 INCHES THURS INTO FRI PRIMARILY OVER INLAND TO NORTHWEST
PORTIONS OF AREA. ESSENTIALLY EXPECT AN EXTENDED PERIOD OF
UNSETTLED WEATHER WITH CU DEVELOPMENT EACH AFTN AS WELL AS DEBRIS
CLOUDS AND GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS.
THE INCREASED CHC OF CLOUDS AND CONVECTION ALONG WITH LOWERING OF
H5 HEIGHT AND LOW LEVEL THICKNESSES WILL KEEP TEMPS NEAR OR BELOW
NORMAL AFTER MONDAY.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...FRONT SEEMS TO BE STALLED OVER THE SOUTHERN PORTION
OF THE CWA. WINDS ARE NEARLY CALM...WITH A WEAK NORTHERLY
COMPONENT THAT WILL BE REPLACED WITH A SOUTHEAST SEA BREEZE THIS
AFTERNOON. THE HRRR DOES HAVE SOME WEAK CONVECTION WITH THE
RESULTANT...ENOUGH FOR A VCSH MENTION. LIGHT WINDS TONIGHT WITH
SOME STRATUS LIKELY RETURNING AFTER 06Z. SATURDAY...BECOMING VFR
WITH NORTHEAST FLOW. ISOLATED CONVECTION IS EXPECTED...MAINLY
ALONG THE RESULTANT AND OVER THE WESTERN PORTION OF THE CWA WHERE
THE DEEPER MOISTURE WILL RESIDE.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 530 PM FRIDAY...THIS UPDATE CONCERNED WITH INCREASING
CONVECTIVE POPS...MAINLY CLOSER TO SHORE DUE TO THE PCPN MOVING
OFF THE MAINLAND. OTHERWISE...MAINTAINED THE BASICALLY VARIABLE
WIND DIRECTION AT 10 KT OR LESS AHEAD OF THE COOL FRONT THIS
EVENING. WINDS SHOULD ALL BECOME NE-ENE AFTER MIDNIGHT...WITH
SPEEDS AROUND 10 KT. THE SFC PG DOES TIGHTEN AFTER THE CFP...BUT
ITS DELAYED UNTIL DAYLIGHT SAT.
PREVIOUS.....................................................
AS OF 3 PM FRIDAY...WINDS WILL STAY LIGHT THROUGH THE NEAR
TERM...BECOMING VARIABLE AT TIMES AS A COLD FRONT STALLS IN THE
VICINITY. THESE LIGHT WINDS WILL KEEP SEAS MANAGEABLE...AT RIGHT
AROUND 2 FT THROUGH THE PERIOD.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...HIGH PRESSURE TO THE NORTH WILL BUILD SOUTH
WITH WEAK FRONT DISSIPATING OVER OR JUST EAST OF THE WATERS
SATURDAY. HIGH PRESSURE REMAINS IN CONTROL THROUGH THE PERIOD WITH
WEAK GRADIENT KEEPING WINDS LIGHT. INITIALLY WINDS WILL BE FROM
THE NORTH-NORTHEAST BUT VEER TO SOUTHERLY DURING SAT. WINDS REMAIN
SOUTHERLY THROUGH THE END OF THE PERIOD WITH SLIGHT INCREASES EACH
AFTERNOON DUE TO SEA BREEZE DEVELOPMENT. SEAS WILL RUN 2 TO 3
FT.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 330 PM FRIDAY...WINDS WILL HAVE A GREATER SOUTHERLY
COMPONENT ON MONDAY AS COLD FRONT APPROACHES THE AREA. OVERALL
EXPECT A LIGHTER PREVAILING WIND FLOW DOMINATED BY LAND/SEA BREEZE
AS A COLD FRONT DROPS SOUTH AND WEAKENS. DIURNAL FLUCTUATIONS ARE
EXPECTED WITH A SPIKE IN WINDS AND CHOPPIER SEAS EACH AFTN. AS
FRONT LINGERS CLOUDS AND PCP MAY PLAY A ROLE EACH DAY IN STRENGTH
OF SEA BREEZE. SEAS WILL BE PRIMARILY 2 TO 3 FT WITH A LONGER
PERIOD UP TO 12 SEC SE SWELL MIXING IN MON NIGHT THROUGH MID WEEK
FROM VERY DISTANT TROPICAL SYSTEM OUT IN THE TROPICAL ATLANTIC.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...III
NEAR TERM...DCH/REK
SHORT TERM...III
LONG TERM...RGZ
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
357 PM EDT FRI AUG 21 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTHWARD FROM THE EASTERN GREAT LAKES
THIS WEEKEND BRINGING DRIER WEATHER. ANOTHER COLD FRONT WILL
APPROACH FROM THE WEST TUESDAY WITH SCATTERED SHOWERS AND STORMS
RETURNING TO THE FORECAST. FRONT STALLS IN THE AREA DURING THE
MIDDLE OF THE WEAK AND SLOWLY DISSIPATES. DRIER AIR MAY MOVE INTO
THE AREA FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 3 PM FRIDAY... THE COLD FRONT REMAINS TOUGH TO PICK OUT BUT
BASED ON THE LATEST OBS INCLUDING WINDS AND DEWPOINT DEPRESSIONS
IT APPEARS THAT THE FRONT IS BISECTING THE CWA FROM NE TO SW. IT
APPEARS TO BE MERGING WITH THE SEA BREEZE FRONT OVER OUR NC
COUNTIES...WHICH FURTHER COMPLICATES LOCATING THE COLD FRONT.
CONVECTION HAS FINALLY COMMENCED WITH ISOLATED SHOWERS FORMING IN
THE VICINITY OF THE COLD FRONT/SEA BREEZE FRONT CONGLOMERATION.
EXPECT THAT THIS FRONTAL FEATURE WILL CONTINUE TO BE THE FOCUS FOR
SCATTERED CONVECTION FOR THE REMAINDER OF THE AFTERNOON AND INTO
THE EVENING HOURS...WITH ACTIVITY SHUTTING DOWN BY AROUND MIDNIGHT
AS THIS IS ALL PRIMARILY DIURNALLY DRIVEN.
A CONSENSUS OF GUIDANCE GIVES US A NORTH TO SOUTH TEMPERATURE
GRADIENT...WITH LOWER 70S UP NORTH AND MID 70S TO THE SOUTH...AND
ALSO MID 70S AT THE COAST.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...REMAINS OF WEAK FRONT OFF THE NC COAST AT THE
START OF THE PERIOD WILL EXTEND WEST ACROSS NORTHERN SC. ALTHOUGH
THE FRONT WILL BECOME QUITE DIFFUSE BY MIDDAY STILL THINK PRECIP
CHANCES WILL REMAIN ELEVATED ACROSS PORTIONS OF SC. HIGH PRESSURE
BUILDING IN FROM THE NORTH HELPS KEEP PRESSURE GRADIENT
WEAK...WITH WEAK SEA BREEZE DEVELOPMENT IN THE AFTERNOON MASKING
THE FRONT. MOISTURE POOLING ALONG THE FRONT COUPLED WITH DIURNAL
HEATING IS LIKELY TO LEAD TO DEVELOPMENT OF AFTERNOON SHOWERS AND
THUNDERSTORMS. HAVE MAINTAINED INHERITED CHC TO SLIGHT CHC POP
ACROSS ILM SC COUNTIES. PRECIP SHOULD BE WEAKER AND DIURNAL IN
NATURE SO ONCE SUN SETS DEBRIS CLOUD WILL LINGER BUT PRECIP
COVERAGE SHOULD RAPIDLY DECREASE. TEMPERATURES SAT AND SAT NIGHT
WILL BE NEAR CLIMO.
WEAK SURFACE RIDGING REMAINS OVER THE EAST COAST SUN WITH MID
LEVEL FLOW ALOFT BECOMING PROGRESSIVE. WEAK SHORTWAVE MOVES ACROSS
THE SOUTHEAST LATER IN THE DAY...ACCOMPANIED BY AN INCREASED IN
MID LEVEL MOISTURE. THE CORE OF THE SHORTWAVE PASSES SOUTH OF THE
FORECAST AREA BUT PVA AHEAD OF IT COULD GENERATE SOME LATE
AFTERNOON/EVENING CONVECTION ACROSS MAINLY THE SC COUNTIES. WILL
CARRY AFTERNOON EVENING SLIGHT CHC/CHC POP TO COVER THE PASSAGE OF
THE WAVE. DEPENDING ON THE SPEED OF THE WAVE CONVECTION COULD
LINGER INTO THE OVERNIGHT PERIOD...BUT WEAK SUBSIDENCE FOLLOWING
THE SHORTWAVE SHOULD END ANY CONVECTION BY DAY BREAK. TEMPERATURES
WILL REMAIN NEAR CLIMO SUN AND SUN NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 330 PM FRIDAY...SHORTWAVE WILL PUSH A COLD FRONT INTO THE
CAROLINAS BUT IT LOOKS LIKE THIS FRONT WILL BECOME WASHED OUT AND
LINGER JUST SOUTH OR OVER THE COASTAL CAROLINAS. A MID TO UPPER
TROUGH DIGGING DOWN FROM THE GREAT LAKES WILL ALIGN WITH THIS
SHORTWAVE LEAVING A DEEP TROUGH DOWN THE EAST COAST THROUGH MUCH OF
THE UPCOMING WEEK. THE WINDS VEER AROUND TO THE NORTH ALOFT...BUT
OVERALL REMAIN QUITE LIGHT AND VARIABLE WITHOUT MUCH OF A DRIVING
FORCE TO THE FRONT. EXPECT GREATEST CHC OF PCP FARTHER INLAND ON MON
AFTN AND SHOULD PUSH TOWARD THE COAST ON TUES. THIS BOUNDARY ALONG
WITH LOCALIZED CONVERGENCE ALONG SEA BREEZE AND PIEDMONT TROUGH
FURTHER INLAND WILL CONTRIBUTE TO DIURNAL CU DEVELOPMENT AND
CONVECTIVE ACTIVITY. THE MODELS ARE NOT GENERATING TOO MUCH IN THE
WAY OF QPF AND DO NOT EXPECT CONVECTION TO BE TOO WIDESPREAD...BUT
LOCALIZED HEAVIER AMTS ARE LIKELY IN STRONGER STORMS. ANOTHER
SHORTWAVE WILL ROTATE AROUND MAIN TROUGH AND SHOULD ADVECT DRIER AIR
IN FROM THE NORTHWEST BY THURS INTO FRI. PCP WATER VALUES UP CLOSER
TO 1.75 INCHES WILL FALL DOWN BELOW 1.5 INCHES THURS INTO FRI
PRIMARILY OVER INLAND TO NORTHWEST PORTIONS OF AREA. ESSENTIALLY
EXPECT AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH CU DEVELOPMENT
EACH AFTN AS WELL AS DEBRIS CLOUDS AND GOOD CHANCES FOR SHOWERS AND
THUNDERSTORMS.
THE INCREASED CHC OF CLOUDS AND CONVECTION ALONG WITH LOWERING OF H5
HEIGHT AND LOW LEVEL THICKNESSES WILL KEEP TEMPS NEAR OR BELOW
NORMAL AFTER MONDAY.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...FRONT SEEMS TO BE STALLED OVER THE SOUTHERN PORTION
OF THE CWA. WINDS ARE NEARLY CALM...WITH A WEAK NORTHERLY
COMPONENT THAT WILL BE REPLACED WITH A SOUTHEAST SEA BREEZE THIS
AFTERNOON. THE HRRR DOES HAVE SOME WEAK CONVECTION WITH THE
RESULTANT...ENOUGH FOR A VCSH MENTION. LIGHT WINDS TONIGHT WITH
SOME STRATUS LIKELY RETURNING AFTER 06Z. SATURDAY...BECOMING VFR
WITH NORTHEAST FLOW. ISOLATED CONVECTION IS EXPECTED...MAINLY
ALONG THE RESULTANT AND OVER THE WESTERN PORTION OF THE CWA WHERE
THE DEEPER MOISTURE WILL RESIDE.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM FRIDAY...WINDS WILL STAY LIGHT THROUGH THE NEAR
TERM...BECOMING VARIABLE AT TIMES AS A COLD FRONT STALLS IN THE
VICINITY. THESE LIGHT WINDS WILL KEEP SEAS MANAGEABLE...AT RIGHT
AROUND 2 FT THROUGH THE PERIOD.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...HIGH PRESSURE TO THE NORTH WILL BUILD SOUTH
WITH WEAK FRONT DISSIPATING OVER OR JUST EAST OF THE WATERS
SATURDAY. HIGH PRESSURE REMAINS IN CONTROL THROUGH THE PERIOD WITH
WEAK GRADIENT KEEPING WINDS LIGHT. INITIALLY WINDS WILL BE FROM
THE NORTH-NORTHEAST BUT VEER TO SOUTHERLY DURING SAT. WINDS REMAIN
SOUTHERLY THROUGH THE END OF THE PERIOD WITH SLIGHT INCREASES EACH
AFTERNOON DUE TO SEA BREEZE DEVELOPMENT. SEAS WILL RUN 2 TO 3
FT.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 330 PM FRIDAY...WINDS WILL HAVE A GREATER SOUTHERLY COMPONENT
ON MONDAY AS COLD FRONT APPROACHES THE AREA. OVERALL EXPECT A
LIGHTER PREVAILING WIND FLOW DOMINATED BY LAND/SEA BREEZE AS A COLD
FRONT DROPS SOUTH AND WEAKENS. DIURNAL FLUCTUATIONS ARE EXPECTED
WITH A SPIKE IN WINDS AND CHOPPIER SEAS EACH AFTN. AS FRONT LINGERS
CLOUDS AND PCP MAY PLAY A ROLE EACH DAY IN STRENGTH OF SEA BREEZE.
SEAS WILL BE PRIMARILY 2 TO 3 FT WITH A LONGER PERIOD UP TO 12 SEC
SE SWELL MIXING IN MON NIGHT THROUGH MID WEEK FROM VERY DISTANT
TROPICAL SYSTEM OUT IN THE TROPICAL ATLANTIC.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK
SHORT TERM...III
LONG TERM...RGZ
AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
130 PM EDT FRI AUG 21 2015
.SYNOPSIS...
A COLD FRONT WILL WAVER ACROSS THE AREA TODAY...BRINGING A
RENEWED CHANCE FOR SHOWERS AND THUNDERSTORMS. MOSTLY SUNNY AND
SEASONABLE WEATHER WILL FOLLOW FOR THE WEEKEND BEHIND THIS FRONT.
WARMER AND MORE HUMID AIR WILL RETURN NEXT WEEK AHEAD OF A COLD
FRONT WHICH WILL APPROACH ON TUESDAY...AND THEN STALL ACROSS THE
AREA THROUGH THURSDAY BRINGING COOLER AND UNSETTLED CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM FRIDAY...AS EXPECTED...STILL WAITING ON THE FIRST
SIGNIFICANT CONVECTION OF THE DAY TO FIRE OFF. AN EXTENSIVE CU
FIELD HAS DEVELOPED HOWEVER...AND GIVEN STRONG HEATING AND A MOIST
COLUMN WILL LIKELY SEE OUR FIRST SHOWERS OF THE DAY FORM SOON.
RETAINING CHANCE POPS FOR THIS AFTERNOON/EVENING. PREVIOUS
DISCUSSIONS FOLLOW:
HARD TO PICK OUT THE FRONT THIS MORNING. BASED ON WIND DIRECTIONS
IT APPEARS TO BE WAVERING ACROSS THE AREA AND MAY BE JUST OFFSHORE
AT THIS TIME. ANALYSIS OF MORNING SOUNDING DATA SHOWS A VERY MOIST
ATMOSPHERE WITH DEWPOINTS WELL IN THE 70S AND P/W VALUES
APPROACHING 2.25 INCHES. NAM IS STILL LIKING SCATTERED CONVECTION
THIS AFTERNOON...ESPECIALLY NEAR THE COAST...ALTHOUGH THE HRRR
CONTINUES IN A MORE MODEST VEIN...WITH ISOLATED SEA-BREEZE
CONVECTION FIRING UP THIS AFTERNOON. KEEPING PRESENT CHANCE POPS
IN PLACE AS WITH SUCH A MOIST COLUMN IT WILL NOT TAKE MUCH TO KICK
OFF CONVECTION. PREVIOUS DISCUSSION FOLLOWS:
DESPITE GREAT MODEL-TO-MODEL CONSISTENCY 24 HOURS AGO THE COLD
FRONT IS LAGGING THOSE PROGS BY NEARLY 100 MILES THIS MORNING. AT
6 AM THE FRONT APPEARS TO LIE ROUGHLY ALONG A LINE FROM
ELIZABETHTOWN AND WHITEVILLE TO MYRTLE BEACH AND GEORGETOWN. THIS
IS ANALYZED MORE BY PRESSURE THAN WIND SINCE WINDS ARE NEARLY CALM
ON EITHER SIDE OF THE BOUNDARY. THE FRONT SHOULD CROSS THE NORTH
CAROLINA BEACHES IN THE NEXT 1-2 HOURS...BUT WITH LITTLE WIND
BEHIND THE FRONT THERE WILL BE NO SIGNIFICANT AIRMASS CHANGE.
TEMPERATURES RISING INTO THE LOWER 90S INLAND THIS AFTERNOON
SHOULD TRIGGER A SEABREEZE WHICH WILL MOVE THE EFFECTIVE LOCATION
OF THE FRONT BACK INLAND DUE TO DEVELOPING ONSHORE WINDS ALONG THE
COAST.
WITH DEWPOINTS HOLDING IN THE LOWER 70S SURFACE-BASED INSTABILITY
SHOULD GROW TO 1000-2000 J/KG THIS AFTERNOON. SYNOPTIC AND FINE-
SCALE MODELS ALL SHOW THE POTENTIAL FOR AT LEAST SCATTERED SHOWERS
AND STORMS THIS AFTERNOON...MOST NUMEROUS NEAR THE COAST WHERE
SEABREEZE-ENHANCED CONVERGENCE WILL ASSIST THE GROWING CUMULUS
CLOUDS. FORECAST POPS RANGE FROM 20 PERCENT INLAND TO 30-40 PERCENT
ON THE COAST. LIGHT TROPOSPHERIC WINDS MEAN ANY CONVECTION WILL
LIKELY BE DISORGANIZED PULSE-TYPE WITH NO SIGNIFICANT POTENTIAL FOR
SEVERE WEATHER.
DAYTIME CLOUDS WILL BE SLOW TO CLEAR TONIGHT ESPECIALLY ACROSS SOUTH
CAROLINA WHERE A MID-LEVEL DISTURBANCE IS PROGGED TO MOVE IN FROM
THE WEST DURING THE EVENING HOURS. THIS SHOULD SPREAD MID-LEVEL
CLOUDS EASTWARD TOWARD THE COAST. A SMALL CHANCE OF SHOWERS AND
STORMS WILL BE MAINTAINED OVERNIGHT ACROSS THE PEE DEE REGION DUE TO
THE MOISTURE ADVECTING EASTWARD...AND OVERNIGHT LOWS HAVE BEEN
ADJUSTED UPWARD DUE TO LESS RADIATIONAL COOLING EXPECTED.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A BEAUTIFUL WKND IN STORE AS A COLD FRONT WILL
BE WELL SOUTH OF THE AREA...LEAVING DRYING AND MOSTLY SUNNY
CONDITIONS FOR SATURDAY AND SUNDAY. SATURDAY STILL HAS A CHANCE FOR
SOME ISOLATED SHOWERS/TSTMS ACROSS THE SOUTHERN TIER OF ZONES WHERE
PWATS WILL BE HIGHER AND THE FRONT WILL STILL BE IN THE
VICINITY...POTENTIALLY INTERACTING WITH A WEAK SHORTWAVE MOVING IN
FROM THE MIDLANDS OF SC...BUT NOT EXPECTING WIDESPREAD OR HEAVY
CONVECTION...AND INTENSITY/COVERAGE WILL DECREASE THROUGH THE
AFTN/EVE ON THE DRY ADVECTION. SUNDAY STILL SHAPING UP TO BE A
GORGEOUS DAY...ALTHOUGH FLOW IS PROGGED TO RETURN TO THE SW
EARLIER THAN PREVIOUSLY. THIS WILL CAUSE TEMPS TO BE
WARMER...ALONG WITH SLIGHTLY HIGHER HUMIDITY THAN PREVIOUSLY
FORECAST...BUT STILL EXPECT BRIGHT SUNSHINE AND A GREAT LATE-
AUGUST DAY.
TEMPS SATURDAY WILL BE AROUND SEASONABLE LEVELS AS COOL ADVECTION IS
LACKING BEHIND THE FRONT. EXPECT HIGHS AROUND 87 FAR NW TO ABOUT 90
ALONG THE SOUTHERN TIER. MAX TEMPS ON SUNDAY WILL BE ABOUT 1-3
DEGREES WARMER EVERYWHERE. SUB-CLIMO MINS SATURDAY NIGHT THANKS TO
THE DRY COLUMN...AND LOWS WILL DROP INTO THE REFRESHING
CATEGORY...DROPPING INTO THE MID 60S WELL NW TO AROUND 70 AT THE
COAST. MORE TYPICAL MINS SUNDAY NIGHT WITH LOWS A DEGREE OR TWO
EITHER SIDE OF 70.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 AM FRIDAY...MID-LEVEL FLOW TO BECOME ANOMALOUSLY AMPLIFIED
FOR AUGUST MUCH OF THE UPCOMING WEEK AS A LARGE TROUGH DEVELOPS
ACROSS THE EAST WITH A BIG RIDGE BLOSSOMING OVER THE MTN WEST.
ALTHOUGH MONDAY WILL FEATURE WARM TEMPS...POSSIBLY ABOVE
NORMAL...WITH TYPICAL SUMMERTIME CONVECTION CHANCES...THIS IS
LOOKING TO BE THE ONE ABOVE-NORMAL DAY OF THE PERIOD. THEREAFTER A
COLD FRONT DROPS INTO THE CAROLINAS AND STALLS THROUGH MID-WEEK
BEFORE FINALLY GETTING PUSHED SOUTH LATE WED INTO THU. THIS WILL
CREATE AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH GOOD CHANCES FOR
SHOWERS AND THUNDERSTORMS...ALONG WITH SUB-CLIMO TEMPS THANKS TO
LOWERED THICKNESSES WITHIN THE TROUGH COMBINING WITH CLOUDS AND
PRECIP. HARD TO SAY THE ENTIRE TUE-THU PERIOD WILL BE WET AND
CLOUDY...BUT AT LEAST A GOOD PORTION OF EACH DAY LOOKS TO BE
UNSETTLED WITH HIGHS SLIGHTLY BELOW CLIMO AND LOWS SLIGHTLY ABOVE AS
DIURNAL RANGES BECOME COMPRESSED
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...FRONT SEEMS TO BE STALLED OVER THE SOUTHERN PORTION
OF THE CWA. WINDS ARE NEARLY CALM...WITH A WEAK NORTHERLY
COMPONENT THAT WILL BE REPLACED WITH A SOUTHEAST SEA BREEZE THIS
AFTERNOON. THE HRRR DOES HAVE SOME WEAK CONVECTION WITH THE
RESULTANT...ENOUGH FOR A VCSH MENTION. LIGHT WINDS TONIGHT WITH
SOME STRATUS LIKELY RETURNING AFTER 06Z. SATURDAY...BECOMING VFR
WITH NORTHEAST FLOW. ISOLATED CONVECTION IS EXPECTED...MAINLY
ALONG THE RESULTANT AND OVER THE WESTERN PORTION OF THE CWA WHERE
THE DEEPER MOISTURE WILL RESIDE.
EXTENDED OUTLOOK...PREDOMINATELY VFR WITH SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM FRIDAY...LIGHT AND VARIABLE WINDS WITH 2 FT WAVES
CONTINUE OVER THE WATERS THIS AFTERNOON AS A COLD FRONT WAVERS IN
THE VICINITY. NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE.
PREVIOUS DISCUSSION FOLLOWS:
SLOW-MOVING COLD FRONT SHOULD MOVE OFF THE BEACHES SHORTLY AFTER
SUNRISE THIS MORNING. WESTERLY WINDS IN ADVANCE OF THE FRONT WILL
VEER NORTHERLY LATER THIS MORNING BUT WITH NO INCREASE IN WIND
SPEED. BY THIS AFTERNOON THE TYPICAL SEABREEZE CIRCULATION SHOULD
OVERWHELM WHAT LITTLE WIND EXISTS BEHIND THE FRONT...WITH ONSHORE
WINDS 10 KNOTS OR LESS EXPECTED ALL ALONG THE COAST. ENOUGH
MOISTURE WILL REMAIN BEHIND THE FRONT THAT A FEW SHOWERS AND
STORMS SHOULD FIRE UP DURING THE AFTERNOON HOURS NEAR THE COAST
ALONG THE SEABREEZE BOUNDARY. STEERING WINDS ALOFT WILL BE LIGHT
AND FROM THE NORTHWEST...PERHAPS PUSHING ANY OF THIS ISOLATED
SHOWER/STORM ACTIVITY OUT ACROSS THE BEACHES AND INTO THE COASTAL
WATERS.
A NORTH-NORTHEAST WIND WILL GRADUALLY INCREASE LATE TONIGHT...
REACHING 10-15 KNOTS LATE. SEAS SHOULD AVERAGE ONLY 2 FEET TODAY AND
TONIGHT...PERHAPS BUILDING TO 3 FEET IN EXPOSED WATERS LATE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...HIGH PRESSURE RIDGING DOWN THE COAST BEHIND A
COLD FRONT WILL CREATE N/NE WINDS SATURDAY AND THE FIRST HALF OF
SUNDAY. THE GRADIENT ASSOCIATED WITH THIS HIGH PRESSURE IS WEAK...SO
WIND SPEEDS WILL BE 10 KTS OR LESS FROM THIS DIRECTION...AFTER A
BRIEF SURGE UP TO 15 KTS EARLY SATURDAY. LATE SUNDAY...RETURN FLOW
WILL BEGIN TO REDEVELOP AS WINDS SHIFT BACK AROUND TO THE SW BUT AT
CONTINUED LIGHT SPEEDS. WAVE HEIGHTS WILL BE 2-3 FT EARLY DURING THE
RESIDUAL NE SURGE...BUT FALL TO 1-2 FT SATURDAY AFTN AND PERSIST AT
THESE AMPLITUDES THROUGH THE WIND SHIFT AND INTO THE END OF THE
PERIOD
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...SW WINDS AHEAD OF A COLD FRONT WILL INCREASE
STEADILY DURING MONDAY...RISING UP TOWARDS 15 KTS LATE IN THE DAY.
AS THE COLD FRONT APPROACHES WINDS WILL EASE A BIT MONDAY
NIGHT...BUT THIS FRONT WILL LIKELY NOT REACH THE WATERS DURING
TUESDAY AND INSTEAD STALL JUST INLAND. THIS WILL CONTINUE S/SW WINDS
TUESDAY AT 10-15 KTS. SEAS WILL BE PRIMARILY 2-3 FT THROUGH THE
PERIOD WITH A SE GROUND SWELL AND WEAK WIND WAVE COMPRISING THE
SPECTRUM. LATE MONDAY AND INTO TUESDAY...SOME 12-SEC PERIOD SWELL
FROM DISTANT TROPICAL SYSTEMS MAY ENTER THE SPECTRUM...BUT WILL BE
AT 1 FT OR LESS IN AMPLITUDE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...REK/TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DL
MARINE...REK/TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1020 AM EDT FRI AUG 21 2015
.SYNOPSIS...
A COLD FRONT WILL WAVER ACROSS THE AREA TODAY...BRINGING A
RENEWED CHANCE FOR SHOWERS AND THUNDERSTORMS. MOSTLY SUNNY AND
SEASONABLE WEATHER WILL FOLLOW FOR THE WEEKEND BEHIND THIS FRONT.
WARMER AND MORE HUMID AIR WILL RETURN NEXT WEEK AHEAD OF A COLD
FRONT WHICH WILL APPROACH ON TUESDAY...AND THEN STALL ACROSS THE
AREA THROUGH THURSDAY BRINGING COOLER AND UNSETTLED CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM FRIDAY...HARD TO PICK OUT THE FRONT THIS MORNING.
BASED ON WIND DIRECTIONS IT APPEARS TO BE WAVERING ACROSS THE AREA
AND MAY BE JUST OFFSHORE AT THIS TIME. ANALYSIS OF MORNING
SOUNDING DATA SHOWS A VERY MOIST ATMOSPHERE WITH DEWPOINTS WELL IN
THE 70S AND P/W VALUES APPROACHING 2.25 INCHES. NAM IS STILL
LIKING SCATTERED CONVECTION THIS AFTERNOON...ESPECIALLY NEAR THE
COAST...ALTHOUGH THE HRRR CONTINUES IN A MORE MODEST VEIN...WITH
ISOLATED SEA-BREEZE CONVECTION FIRING UP THIS AFTERNOON. KEEPING
PRESENT CHANCE POPS IN PLACE AS WITH SUCH A MOIST COLUMN IT WILL
NOT TAKE MUCH TO KICK OFF CONVECTION. PREVIOUS DISCUSSION FOLLOWS:
DESPITE GREAT MODEL-TO-MODEL CONSISTENCY 24 HOURS AGO THE COLD
FRONT IS LAGGING THOSE PROGS BY NEARLY 100 MILES THIS MORNING. AT
6 AM THE FRONT APPEARS TO LIE ROUGHLY ALONG A LINE FROM
ELIZABETHTOWN AND WHITEVILLE TO MYRTLE BEACH AND GEORGETOWN. THIS
IS ANALYZED MORE BY PRESSURE THAN WIND SINCE WINDS ARE NEARLY CALM
ON EITHER SIDE OF THE BOUNDARY. THE FRONT SHOULD CROSS THE NORTH
CAROLINA BEACHES IN THE NEXT 1-2 HOURS...BUT WITH LITTLE WIND
BEHIND THE FRONT THERE WILL BE NO SIGNIFICANT AIRMASS CHANGE.
TEMPERATURES RISING INTO THE LOWER 90S INLAND THIS AFTERNOON
SHOULD TRIGGER A SEABREEZE WHICH WILL MOVE THE EFFECTIVE LOCATION
OF THE FRONT BACK INLAND DUE TO DEVELOPING ONSHORE WINDS ALONG THE
COAST.
WITH DEWPOINTS HOLDING IN THE LOWER 70S SURFACE-BASED INSTABILITY
SHOULD GROW TO 1000-2000 J/KG THIS AFTERNOON. SYNOPTIC AND FINE-
SCALE MODELS ALL SHOW THE POTENTIAL FOR AT LEAST SCATTERED SHOWERS
AND STORMS THIS AFTERNOON...MOST NUMEROUS NEAR THE COAST WHERE
SEABREEZE-ENHANCED CONVERGENCE WILL ASSIST THE GROWING CUMULUS
CLOUDS. FORECAST POPS RANGE FROM 20 PERCENT INLAND TO 30-40 PERCENT
ON THE COAST. LIGHT TROPOSPHERIC WINDS MEAN ANY CONVECTION WILL
LIKELY BE DISORGANIZED PULSE-TYPE WITH NO SIGNIFICANT POTENTIAL FOR
SEVERE WEATHER.
DAYTIME CLOUDS WILL BE SLOW TO CLEAR TONIGHT ESPECIALLY ACROSS SOUTH
CAROLINA WHERE A MID-LEVEL DISTURBANCE IS PROGGED TO MOVE IN FROM
THE WEST DURING THE EVENING HOURS. THIS SHOULD SPREAD MID-LEVEL
CLOUDS EASTWARD TOWARD THE COAST. A SMALL CHANCE OF SHOWERS AND
STORMS WILL BE MAINTAINED OVERNIGHT ACROSS THE PEE DEE REGION DUE TO
THE MOISTURE ADVECTING EASTWARD...AND OVERNIGHT LOWS HAVE BEEN
ADJUSTED UPWARD DUE TO LESS RADIATIONAL COOLING EXPECTED.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A BEAUTIFUL WKND IN STORE AS A COLD FRONT WILL
BE WELL SOUTH OF THE AREA...LEAVING DRYING AND MOSTLY SUNNY
CONDITIONS FOR SATURDAY AND SUNDAY. SATURDAY STILL HAS A CHANCE FOR
SOME ISOLATED SHOWERS/TSTMS ACROSS THE SOUTHERN TIER OF ZONES WHERE
PWATS WILL BE HIGHER AND THE FRONT WILL STILL BE IN THE
VICINITY...POTENTIALLY INTERACTING WITH A WEAK SHORTWAVE MOVING IN
FROM THE MIDLANDS OF SC...BUT NOT EXPECTING WIDESPREAD OR HEAVY
CONVECTION...AND INTENSITY/COVERAGE WILL DECREASE THROUGH THE
AFTN/EVE ON THE DRY ADVECTION. SUNDAY STILL SHAPING UP TO BE A
GORGEOUS DAY...ALTHOUGH FLOW IS PROGGED TO RETURN TO THE SW
EARLIER THAN PREVIOUSLY. THIS WILL CAUSE TEMPS TO BE
WARMER...ALONG WITH SLIGHTLY HIGHER HUMIDITY THAN PREVIOUSLY
FORECAST...BUT STILL EXPECT BRIGHT SUNSHINE AND A GREAT LATE-
AUGUST DAY.
TEMPS SATURDAY WILL BE AROUND SEASONABLE LEVELS AS COOL ADVECTION IS
LACKING BEHIND THE FRONT. EXPECT HIGHS AROUND 87 FAR NW TO ABOUT 90
ALONG THE SOUTHERN TIER. MAX TEMPS ON SUNDAY WILL BE ABOUT 1-3
DEGREES WARMER EVERYWHERE. SUB-CLIMO MINS SATURDAY NIGHT THANKS TO
THE DRY COLUMN...AND LOWS WILL DROP INTO THE REFRESHING
CATEGORY...DROPPING INTO THE MID 60S WELL NW TO AROUND 70 AT THE
COAST. MORE TYPICAL MINS SUNDAY NIGHT WITH LOWS A DEGREE OR TWO
EITHER SIDE OF 70.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MID-LEVEL FLOW TO BECOME ANOMALOUSLY AMPLIFIED
FOR AUGUST MUCH OF THE UPCOMING WEEK AS A LARGE TROUGH DEVELOPS
ACROSS THE EAST WITH A BIG RIDGE BLOSSOMING OVER THE MTN WEST.
ALTHOUGH MONDAY WILL FEATURE WARM TEMPS...POSSIBLY ABOVE
NORMAL...WITH TYPICAL SUMMERTIME CONVECTION CHANCES...THIS IS
LOOKING TO BE THE ONE ABOVE-NORMAL DAY OF THE PERIOD. THEREAFTER A
COLD FRONT DROPS INTO THE CAROLINAS AND STALLS THROUGH MID-WEEK
BEFORE FINALLY GETTING PUSHED SOUTH LATE WED INTO THU. THIS WILL
CREATE AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH GOOD CHANCES FOR
SHOWERS AND THUNDERSTORMS...ALONG WITH SUB-CLIMO TEMPS THANKS TO
LOWERED THICKNESSES WITHIN THE TROUGH COMBINING WITH CLOUDS AND
PRECIP. HARD TO SAY THE ENTIRE TUE-THU PERIOD WILL BE WET AND
CLOUDY...BUT AT LEAST A GOOD PORTION OF EACH DAY LOOKS TO BE
UNSETTLED WITH HIGHS SLIGHTLY BELOW CLIMO AND LOWS SLIGHTLY ABOVE AS
DIURNAL RANGES BECOME COMPRESSED
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...COLD FRONT PUSHING SOUTH THROUGH THE REGION AT THIS
TIME. NO WEATHER ASSOCIATED WITH IT...JUST A WIND SHIFT TO THE
NORTHWEST. THE HRRR MODEL HAS ISOLATED CONVECTION POPPING UP THIS
AFTERNOON...BUT THAT IS A BIT OF A STRETCH AS THERE WILL NOT BE MUCH
MOISTURE TO WORK WITH. WINDS CONTINUE TO VEER TO THE NORTHEAST BY
AFTERNOON. LIGHT WINDS OVERNIGHT WITH LITTLE OR NO FOG EXPECTED.
EXTENDED OUTLOOK...VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM FRIDAY...LIGHT AND VARIABLE WINDS WITH 2 FT WAVES
OVER THE WATERS THIS MORNING AS A COLD FRONT WAVERS IN THE
VICINITY. NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE.
PREVIOUS DISCUSSION FOLLOWS:
SLOW-MOVING COLD FRONT SHOULD MOVE OFF THE BEACHES SHORTLY AFTER
SUNRISE THIS MORNING. WESTERLY WINDS IN ADVANCE OF THE FRONT WILL
VEER NORTHERLY LATER THIS MORNING BUT WITH NO INCREASE IN WIND
SPEED. BY THIS AFTERNOON THE TYPICAL SEABREEZE CIRCULATION SHOULD
OVERWHELM WHAT LITTLE WIND EXISTS BEHIND THE FRONT...WITH ONSHORE
WINDS 10 KNOTS OR LESS EXPECTED ALL ALONG THE COAST. ENOUGH
MOISTURE WILL REMAIN BEHIND THE FRONT THAT A FEW SHOWERS AND
STORMS SHOULD FIRE UP DURING THE AFTERNOON HOURS NEAR THE COAST
ALONG THE SEABREEZE BOUNDARY. STEERING WINDS ALOFT WILL BE LIGHT
AND FROM THE NORTHWEST...PERHAPS PUSHING ANY OF THIS ISOLATED
SHOWER/STORM ACTIVITY OUT ACROSS THE BEACHES AND INTO THE COASTAL
WATERS.
A NORTH-NORTHEAST WIND WILL GRADUALLY INCREASE LATE TONIGHT...
REACHING 10-15 KNOTS LATE. SEAS SHOULD AVERAGE ONLY 2 FEET TODAY AND
TONIGHT...PERHAPS BUILDING TO 3 FEET IN EXPOSED WATERS LATE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...HIGH PRESSURE RIDGING DOWN THE COAST BEHIND A
COLD FRONT WILL CREATE N/NE WINDS SATURDAY AND THE FIRST HALF OF
SUNDAY. THE GRADIENT ASSOCIATED WITH THIS HIGH PRESSURE IS WEAK...SO
WIND SPEEDS WILL BE 10 KTS OR LESS FROM THIS DIRECTION...AFTER A
BRIEF SURGE UP TO 15 KTS EARLY SATURDAY. LATE SUNDAY...RETURN FLOW
WILL BEGIN TO REDEVELOP AS WINDS SHIFT BACK AROUND TO THE SW BUT AT
CONTINUED LIGHT SPEEDS. WAVE HEIGHTS WILL BE 2-3 FT EARLY DURING THE
RESIDUAL NE SURGE...BUT FALL TO 1-2 FT SATURDAY AFTN AND PERSIST AT
THESE AMPLITUDES THROUGH THE WIND SHIFT AND INTO THE END OF THE
PERIOD
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...SW WINDS AHEAD OF A COLD FRONT WILL INCREASE
STEADILY DURING MONDAY...RISING UP TOWARDS 15 KTS LATE IN THE DAY.
AS THE COLD FRONT APPROACHES WINDS WILL EASE A BIT MONDAY
NIGHT...BUT THIS FRONT WILL LIKELY NOT REACH THE WATERS DURING
TUESDAY AND INSTEAD STALL JUST INLAND. THIS WILL CONTINUE S/SW WINDS
TUESDAY AT 10-15 KTS. SEAS WILL BE PRIMARILY 2-3 FT THROUGH THE
PERIOD WITH A SE GROUND SWELL AND WEAK WIND WAVE COMPRISING THE
SPECTRUM. LATE MONDAY AND INTO TUESDAY...SOME 12-SEC PERIOD SWELL
FROM DISTANT TROPICAL SYSTEMS MAY ENTER THE SPECTRUM...BUT WILL BE
AT 1 FT OR LESS IN AMPLITUDE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...REK/TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DL
MARINE...REK/TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
636 AM EDT FRI AUG 21 2015
.SYNOPSIS...
A COLD FRONT WILL WAVER ACROSS THE AREA TODAY BRINGING A RENEWED
CHANCE FOR SHOWERS AND THUNDERSTORMS. MOSTLY SUNNY AND SEASONABLE
WEATHER WILL FOLLOW FOR THE WEEKEND BEHIND THIS FRONT. WARMER AND
MORE HUMID AIR WILL RETURN NEXT WEEK AHEAD OF A COLD FRONT WHICH
WILL APPROACH ON TUESDAY...AND THEN STALL ACROSS THE AREA THROUGH
THURSDAY BRINGING COOLER AND UNSETTLED CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...DESPITE GREAT MODEL-TO-MODEL CONSISTENCY 24
HOURS AGO THE COLD FRONT IS LAGGING THOSE PROGS BY NEARLY 100 MILES
THIS MORNING. AT 6 AM THE FRONT APPEARS TO LIE ROUGHLY ALONG A LINE
FROM ELIZABETHTOWN AND WHITEVILLE TO MYRTLE BEACH AND GEORGETOWN.
THIS IS ANALYZED MORE BY PRESSURE THAN WIND SINCE WINDS ARE NEARLY
CALM ON EITHER SIDE OF THE BOUNDARY. THE FRONT SHOULD CROSS THE
NORTH CAROLINA BEACHES IN THE NEXT 1-2 HOURS...BUT WITH LITTLE WIND
BEHIND THE FRONT THERE WILL BE NO SIGNIFICANT AIRMASS CHANGE.
TEMPERATURES RISING INTO THE LOWER 90S INLAND THIS AFTERNOON SHOULD
TRIGGER A SEABREEZE WHICH WILL MOVE THE EFFECTIVE LOCATION OF THE
FRONT BACK INLAND DUE TO DEVELOPING ONSHORE WINDS ALONG THE COAST.
WITH DEWPOINTS HOLDING IN THE LOWER 70S SURFACE-BASED INSTABILITY
SHOULD GROW TO 1000-2000 J/KG THIS AFTERNOON. SYNOPTIC AND FINE-
SCALE MODELS ALL SHOW THE POTENTIAL FOR AT LEAST SCATTERED SHOWERS
AND STORMS THIS AFTERNOON...MOST NUMEROUS NEAR THE COAST WHERE
SEABREEZE-ENHANCED CONVERGENCE WILL ASSIST THE GROWING CUMULUS
CLOUDS. FORECAST POPS RANGE FROM 20 PERCENT INLAND TO 30-40 PERCENT
ON THE COAST. LIGHT TROPOSPHERIC WINDS MEAN ANY CONVECTION WILL
LIKELY BE DISORGANIZED PULSE-TYPE WITH NO SIGNIFICANT POTENTIAL FOR
SEVERE WEATHER.
DAYTIME CLOUDS WILL BE SLOW TO CLEAR TONIGHT ESPECIALLY ACROSS SOUTH
CAROLINA WHERE A MID-LEVEL DISTURBANCE IS PROGGED TO MOVE IN FROM
THE WEST DURING THE EVENING HOURS. THIS SHOULD SPREAD MID-LEVEL
CLOUDS EASTWARD TOWARD THE COAST. A SMALL CHANCE OF SHOWERS AND
STORMS WILL BE MAINTAINED OVERNIGHT ACROSS THE PEE DEE REGION DUE TO
THE MOISTURE ADVECTING EASTWARD...AND OVERNIGHT LOWS HAVE BEEN
ADJUSTED UPWARD DUE TO LESS RADIATIONAL COOLING EXPECTED.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A BEAUTIFUL WKND IN STORE AS A COLD FRONT WILL
BE WELL SOUTH OF THE AREA...LEAVING DRYING AND MOSTLY SUNNY
CONDITIONS FOR SATURDAY AND SUNDAY. SATURDAY STILL HAS A CHANCE FOR
SOME ISOLATED SHOWERS/TSTMS ACROSS THE SOUTHERN TIER OF ZONES WHERE
PWATS WILL BE HIGHER AND THE FRONT WILL STILL BE IN THE
VICINITY...POTENTIALLY INTERACTING WITH A WEAK SHORTWAVE MOVING IN
FROM THE MIDLANDS OF SC...BUT NOT EXPECTING WIDESPREAD OR HEAVY
CONVECTION...AND INTENSITY/COVERAGE WILL DECREASE THROUGH THE
AFTN/EVE ON THE DRY ADVECTION. SUNDAY STILL SHAPING UP TO BE A
GORGEOUS DAY...ALTHOUGH FLOW IS PROGGED TO RETURN TO THE SW
EARLIER THAN PREVIOUSLY. THIS WILL CAUSE TEMPS TO BE
WARMER...ALONG WITH SLIGHTLY HIGHER HUMIDITY THAN PREVIOUSLY
FORECAST...BUT STILL EXPECT BRIGHT SUNSHINE AND A GREAT LATE-
AUGUST DAY.
TEMPS SATURDAY WILL BE AROUND SEASONABLE LEVELS AS COOL ADVECTION IS
LACKING BEHIND THE FRONT. EXPECT HIGHS AROUND 87 FAR NW TO ABOUT 90
ALONG THE SOUTHERN TIER. MAX TEMPS ON SUNDAY WILL BE ABOUT 1-3
DEGREES WARMER EVERYWHERE. SUB-CLIMO MINS SATURDAY NIGHT THANKS TO
THE DRY COLUMN...AND LOWS WILL DROP INTO THE REFRESHING
CATEGORY...DROPPING INTO THE MID 60S WELL NW TO AROUND 70 AT THE
COAST. MORE TYPICAL MINS SUNDAY NIGHT WITH LOWS A DEGREE OR TWO
EITHER SIDE OF 70.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MID-LEVEL FLOW TO BECOME ANOMALOUSLY AMPLIFIED
FOR AUGUST MUCH OF THE UPCOMING WEEK AS A LARGE TROUGH DEVELOPS
ACROSS THE EAST WITH A BIG RIDGE BLOSSOMING OVER THE MTN WEST.
ALTHOUGH MONDAY WILL FEATURE WARM TEMPS...POSSIBLY ABOVE
NORMAL...WITH TYPICAL SUMMERTIME CONVECTION CHANCES...THIS IS
LOOKING TO BE THE ONE ABOVE-NORMAL DAY OF THE PERIOD. THEREAFTER A
COLD FRONT DROPS INTO THE CAROLINAS AND STALLS THROUGH MID-WEEK
BEFORE FINALLY GETTING PUSHED SOUTH LATE WED INTO THU. THIS WILL
CREATE AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH GOOD CHANCES FOR
SHOWERS AND THUNDERSTORMS...ALONG WITH SUB-CLIMO TEMPS THANKS TO
LOWERED THICKNESSES WITHIN THE TROUGH COMBINING WITH CLOUDS AND
PRECIP. HARD TO SAY THE ENTIRE TUE-THU PERIOD WILL BE WET AND
CLOUDY...BUT AT LEAST A GOOD PORTION OF EACH DAY LOOKS TO BE
UNSETTLED WITH HIGHS SLIGHTLY BELOW CLIMO AND LOWS SLIGHTLY ABOVE AS
DIURNAL RANGES BECOME COMPRESSED
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...COLD FRONT PUSHING SOUTH THROUGH THE REGION AT THIS
TIME. NO WEATHER ASSOCIATED WITH IT...JUST A WIND SHIFT TO THE
NORTHWEST. THE HRRR MODEL HAS ISOLATED CONVECTION POPPING UP THIS
AFTERNOON...BUT THAT IS A BIT OF A STRETCH AS THERE WILL NOT BE MUCH
MOISTURE TO WORK WITH. WINDS CONTINUE TO VEER TO THE NORTHEAST BY
AFTERNOON. LIGHT WINDS OVERNIGHT WITH LITTLE OR NO FOG EXPECTED.
EXTENDED OUTLOOK...VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...SLOW-MOVING COLD FRONT SHOULD MOVE OFF THE
BEACHES SHORTLY AFTER SUNRISE THIS MORNING. WESTERLY WINDS IN
ADVANCE OF THE FRONT WILL VEER NORTHERLY LATER THIS MORNING BUT WITH
NO INCREASE IN WIND SPEED. BY THIS AFTERNOON THE TYPICAL SEABREEZE
CIRCULATION SHOULD OVERWHELM WHAT LITTLE WIND EXISTS BEHIND THE
FRONT...WITH ONSHORE WINDS 10 KNOTS OR LESS EXPECTED ALL ALONG THE
COAST. ENOUGH MOISTURE WILL REMAIN BEHIND THE FRONT THAT A FEW
SHOWERS AND STORMS SHOULD FIRE UP DURING THE AFTERNOON HOURS NEAR
THE COAST ALONG THE SEABREEZE BOUNDARY. STEERING WINDS ALOFT WILL BE
LIGHT AND FROM THE NORTHWEST...PERHAPS PUSHING ANY OF THIS ISOLATED
SHOWER/STORM ACTIVITY OUT ACROSS THE BEACHES AND INTO THE COASTAL
WATERS.
A NORTH-NORTHEAST WIND WILL GRADUALLY INCREASE LATE TONIGHT...
REACHING 10-15 KNOTS LATE. SEAS SHOULD AVERAGE ONLY 2 FEET TODAY AND
TONIGHT...PERHAPS BUILDING TO 3 FEET IN EXPOSED WATERS LATE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...HIGH PRESSURE RIDGING DOWN THE COAST BEHIND A
COLD FRONT WILL CREATE N/NE WINDS SATURDAY AND THE FIRST HALF OF
SUNDAY. THE GRADIENT ASSOCIATED WITH THIS HIGH PRESSURE IS WEAK...SO
WIND SPEEDS WILL BE 10 KTS OR LESS FROM THIS DIRECTION...AFTER A
BRIEF SURGE UP TO 15 KTS EARLY SATURDAY. LATE SUNDAY...RETURN FLOW
WILL BEGIN TO REDEVELOP AS WINDS SHIFT BACK AROUND TO THE SW BUT AT
CONTINUED LIGHT SPEEDS. WAVE HEIGHTS WILL BE 2-3 FT EARLY DURING THE
RESIDUAL NE SURGE...BUT FALL TO 1-2 FT SATURDAY AFTN AND PERSIST AT
THESE AMPLITUDES THROUGH THE WIND SHIFT AND INTO THE END OF THE
PERIOD
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...SW WINDS AHEAD OF A COLD FRONT WILL INCREASE
STEADILY DURING MONDAY...RISING UP TOWARDS 15 KTS LATE IN THE DAY.
AS THE COLD FRONT APPROACHES WINDS WILL EASE A BIT MONDAY
NIGHT...BUT THIS FRONT WILL LIKELY NOT REACH THE WATERS DURING
TUESDAY AND INSTEAD STALL JUST INLAND. THIS WILL CONTINUE S/SW WINDS
TUESDAY AT 10-15 KTS. SEAS WILL BE PRIMARILY 2-3 FT THROUGH THE
PERIOD WITH A SE GROUND SWELL AND WEAK WIND WAVE COMPRISING THE
SPECTRUM. LATE MONDAY AND INTO TUESDAY...SOME 12-SEC PERIOD SWELL
FROM DISTANT TROPICAL SYSTEMS MAY ENTER THE SPECTRUM...BUT WILL BE
AT 1 FT OR LESS IN AMPLITUDE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...43
MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
630 AM EDT FRI AUG 21 2015
.SYNOPSIS...
A COLD FRONT WILL WAVER ACROSS THE AREA TODAY BRINGING A RENEWED
CHANCE FOR SHOWERS AND THUNDERSTORMS. MOSTLY SUNNY AND SEASONABLE
WEATHER WILL FOLLOW FOR THE WEEKEND BEHIND THIS FRONT. WARMER AND
MORE HUMID AIR WILL RETURN NEXT WEEK AHEAD OF A COLD FRONT WHICH
WILL APPROACH ON TUESDAY...AND THEN STALL ACROSS THE AREA THROUGH
THURSDAY BRINGING COOLER AND UNSETTLED CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...DESPITE GREAT MODEL-TO-MODEL CONSISTENCY 24
HOURS AGO THE COLD FRONT IS LAGGING THOSE PROGS BY NEARLY 100 MILES
THIS MORNING. AT 3 AM THE FRONT APPEARS TO LIE ROUGHLY ALONG
INTERSTATE 95...MOVING EASTWARD TOWARD THE COAST AT A SLOW PACE. THE
FRONT SHOULD CROSS THE BEACHES SHORTLY AFTER SUNRISE...BUT WITH
LITTLE WIND BEHIND THE FRONT THERE WILL BE NO SIGNIFICANT AIRMASS
CHANGE. TEMPERATURES RISING INTO THE LOWER 90S INLAND THIS AFTERNOON
SHOULD TRIGGER A SEABREEZE WHICH WILL MOVE THE EFFECTIVE LOCATION OF
THE FRONT BACK INLAND DUE TO DEVELOPING ONSHORE WINDS ALONG THE
COAST.
WITH DEWPOINTS HOLDING IN THE LOWER 70S SURFACE-BASED INSTABILITY
SHOULD GROW TO 1000-2000 J/KG THIS AFTERNOON. SYNOPTIC AND FINE-
SCALE MODELS ALL SHOW THE POTENTIAL FOR AT LEAST SCATTERED SHOWERS
AND STORMS THIS AFTERNOON...MOST NUMEROUS NEAR THE COAST WHERE
SEABREEZE-ENHANCED CONVERGENCE WILL ASSIST THE GROWING CUMULUS
CLOUDS. FORECAST POPS RANGE FROM 20 PERCENT INLAND TO 40 PERCENT ON
THE COAST. LIGHT TROPOSPHERIC WINDS MEAN ANY CONVECTION WILL LIKELY
BE DISORGANIZED PULSE-TYPE WITH NO SIGNIFICANT POTENTIAL FOR SEVERE
WEATHER.
DAYTIME CLOUDS WILL BE SLOW TO CLEAR TONIGHT ESPECIALLY ACROSS SOUTH
CAROLINA WHERE A MID-LEVEL DISTURBANCE IS PROGGED TO MOVE IN FROM
THE WEST DURING THE EVENING HOURS. THIS SHOULD SPREAD MID-LEVEL
CLOUDS EASTWARD TOWARD THE COAST. A SMALL CHANCE OF SHOWERS AND
STORMS WILL BE MAINTAINED OVERNIGHT ACROSS THE PEE DEE REGION DUE TO
THE MOISTURE ADVECTING EASTWARD...AND OVERNIGHT LOWS HAVE BEEN
ADJUSTED UPWARD DUE TO LESS RADIATIONAL COOLING EXPECTED.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A BEAUTIFUL WKND IN STORE AS A COLD FRONT WILL
BE WELL SOUTH OF THE AREA...LEAVING DRYING AND MOSTLY SUNNY
CONDITIONS FOR SATURDAY AND SUNDAY. SATURDAY STILL HAS A CHANCE FOR
SOME ISOLATED SHOWERS/TSTMS ACROSS THE SOUTHERN TIER OF ZONES WHERE
PWATS WILL BE HIGHER AND THE FRONT WILL STILL BE IN THE
VICINITY...POTENTIALLY INTERACTING WITH A WEAK SHORTWAVE MOVING IN
FROM THE MIDLANDS OF SC...BUT NOT EXPECTING WIDESPREAD OR HEAVY
CONVECTION...AND INTENSITY/COVERAGE WILL DECREASE THROUGH THE
AFTN/EVE ON THE DRY ADVECTION. SUNDAY STILL SHAPING UP TO BE A
GORGEOUS DAY...ALTHOUGH FLOW IS PROGGED TO RETURN TO THE SW
EARLIER THAN PREVIOUSLY. THIS WILL CAUSE TEMPS TO BE
WARMER...ALONG WITH SLIGHTLY HIGHER HUMIDITY THAN PREVIOUSLY
FORECAST...BUT STILL EXPECT BRIGHT SUNSHINE AND A GREAT LATE-
AUGUST DAY.
TEMPS SATURDAY WILL BE AROUND SEASONABLE LEVELS AS COOL ADVECTION IS
LACKING BEHIND THE FRONT. EXPECT HIGHS AROUND 87 FAR NW TO ABOUT 90
ALONG THE SOUTHERN TIER. MAX TEMPS ON SUNDAY WILL BE ABOUT 1-3
DEGREES WARMER EVERYWHERE. SUB-CLIMO MINS SATURDAY NIGHT THANKS TO
THE DRY COLUMN...AND LOWS WILL DROP INTO THE REFRESHING
CATEGORY...DROPPING INTO THE MID 60S WELL NW TO AROUND 70 AT THE
COAST. MORE TYPICAL MINS SUNDAY NIGHT WITH LOWS A DEGREE OR TWO
EITHER SIDE OF 70.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MID-LEVEL FLOW TO BECOME ANOMALOUSLY AMPLIFIED
FOR AUGUST MUCH OF THE UPCOMING WEEK AS A LARGE TROUGH DEVELOPS
ACROSS THE EAST WITH A BIG RIDGE BLOSSOMING OVER THE MTN WEST.
ALTHOUGH MONDAY WILL FEATURE WARM TEMPS...POSSIBLY ABOVE
NORMAL...WITH TYPICAL SUMMERTIME CONVECTION CHANCES...THIS IS
LOOKING TO BE THE ONE ABOVE-NORMAL DAY OF THE PERIOD. THEREAFTER A
COLD FRONT DROPS INTO THE CAROLINAS AND STALLS THROUGH MID-WEEK
BEFORE FINALLY GETTING PUSHED SOUTH LATE WED INTO THU. THIS WILL
CREATE AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH GOOD CHANCES FOR
SHOWERS AND THUNDERSTORMS...ALONG WITH SUB-CLIMO TEMPS THANKS TO
LOWERED THICKNESSES WITHIN THE TROUGH COMBINING WITH CLOUDS AND
PRECIP. HARD TO SAY THE ENTIRE TUE-THU PERIOD WILL BE WET AND
CLOUDY...BUT AT LEAST A GOOD PORTION OF EACH DAY LOOKS TO BE
UNSETTLED WITH HIGHS SLIGHTLY BELOW CLIMO AND LOWS SLIGHTLY ABOVE AS
DIURNAL RANGES BECOME COMPRESSED
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...COLD FRONT PUSHING SOUTH THROUGH THE REGION AT THIS
TIME. NO WEATHER ASSOCIATED WITH IT...JUST A WIND SHIFT TO THE
NORTHWEST. THE HRRR MODEL HAS ISOLATED CONVECTION POPPING UP THIS
AFTERNOON...BUT THAT IS A BIT OF A STRETCH AS THERE WILL NOT BE MUCH
MOISTURE TO WORK WITH. WINDS CONTINUE TO VEER TO THE NORTHEAST BY
AFTERNOON. LIGHT WINDS OVERNIGHT WITH LITTLE OR NO FOG EXPECTED.
EXTENDED OUTLOOK...VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...A SLOW-MOVING COLD FRONT SHOULD MOVE OFF THE
BEACHES SHORTLY AFTER SUNRISE THIS MORNING. WESTERLY WINDS IN
ADVANCE OF THE FRONT WILL VEER NORTHERLY THIS MORNING BUT WITH NO
INCREASE IN WIND SPEED. BY THIS AFTERNOON THE TYPICAL SEABREEZE
CIRCULATION SHOULD OVERWHELM WHAT LITTLE WIND EXISTS BEHIND THE
FRONT...WITH ONSHORE WINDS 10 KNOTS OR LESS EXPECTED ALL ALONG THE
COAST. ENOUGH MOISTURE WILL REMAIN BEHIND THE FRONT THAT SCATTERED
SHOWERS AND STORMS SHOULD FIRE UP DURING THE AFTERNOON HOURS NEAR
THE COAST ALONG THE SEABREEZE BOUNDARY. STEERING WINDS ALOFT WILL BE
LIGHT AND FROM THE NORTHWEST...PERHAPS PUSHING ANY SHOWERS AND
STORMS OUT ACROSS THE BEACHES AND INTO THE COASTAL WATERS.
A NORTH-NORTHEAST WIND WILL GRADUALLY INCREASE LATE
TONIGHT...REACHING 10-15 KNOTS LATE. SEAS SHOULD AVERAGE ONLY 2 FEET
TODAY AND TONIGHT...PERHAPS BUILDING TO 3 FEET IN EXPOSED WATERS
LATE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...HIGH PRESSURE RIDGING DOWN THE COAST BEHIND A
COLD FRONT WILL CREATE N/NE WINDS SATURDAY AND THE FIRST HALF OF
SUNDAY. THE GRADIENT ASSOCIATED WITH THIS HIGH PRESSURE IS WEAK...SO
WIND SPEEDS WILL BE 10 KTS OR LESS FROM THIS DIRECTION...AFTER A
BRIEF SURGE UP TO 15 KTS EARLY SATURDAY. LATE SUNDAY...RETURN FLOW
WILL BEGIN TO REDEVELOP AS WINDS SHIFT BACK AROUND TO THE SW BUT AT
CONTINUED LIGHT SPEEDS. WAVE HEIGHTS WILL BE 2-3 FT EARLY DURING THE
RESIDUAL NE SURGE...BUT FALL TO 1-2 FT SATURDAY AFTN AND PERSIST AT
THESE AMPLITUDES THROUGH THE WIND SHIFT AND INTO THE END OF THE
PERIOD
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...SW WINDS AHEAD OF A COLD FRONT WILL INCREASE
STEADILY DURING MONDAY...RISING UP TOWARDS 15 KTS LATE IN THE DAY.
AS THE COLD FRONT APPROACHES WINDS WILL EASE A BIT MONDAY
NIGHT...BUT THIS FRONT WILL LIKELY NOT REACH THE WATERS DURING
TUESDAY AND INSTEAD STALL JUST INLAND. THIS WILL CONTINUE S/SW WINDS
TUESDAY AT 10-15 KTS. SEAS WILL BE PRIMARILY 2-3 FT THROUGH THE
PERIOD WITH A SE GROUND SWELL AND WEAK WIND WAVE COMPRISING THE
SPECTRUM. LATE MONDAY AND INTO TUESDAY...SOME 12-SEC PERIOD SWELL
FROM DISTANT TROPICAL SYSTEMS MAY ENTER THE SPECTRUM...BUT WILL BE
AT 1 FT OR LESS IN AMPLITUDE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...43
MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1208 PM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 1210 PM CDT FRI AUG 21 2015
SMOKE CONTINUES TO SLOW TEMP RISE TODAY...AND WILL LOWER A FEW
MORE DEGREES FOR ALL AREAS. OTHERWISE...NO OTHER CHANGES NEEDED
TODAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
FORECAST CHALLENGES WILL BE SEVERE THREAT SATURDAY AS WELL AS RAINFALL
AMOUNTS MAINLY THIS WEEKEND AND TEMPERATURES/WIND. MODELS OVERALL
IN PRETTY GOOD AGREEMENT THROUGH THE PERIOD AND WILL USE MODEL
BLEND.
CURRENT SHORTWAVE PROPAGATING EAST ACROSS SW MB INTO ONTARIO THIS
MORNING. ASSOCIATED AREA OF SHRA/ISOLD T ON NOSE OF LOW LEVEL JET
IN WARM ADVECTION ZONE. ALTHOUGH INSTABILITY AND CAPE MINIMAL A
FEW LIGHTNING STRIKES OCCURRING. CURRENT HRRR WEAKENS PCPN
THROUGH THE MORNING AND OUT OF THE FA BY MID MORNING. WILL
MAINTAIN LOW POPS BASED ON SHORT TERM MODEL GUIDANCE. THE
REMAINDER OF THIS AFTERNOON SHOULD REMAIN DRY. CONTINUED WARM
ADVECTION WILL SET UP WARM FRONTAL BOUNDARY ALONG THE
INTERNATIONAL BORDER BY THIS EVENING. WITH FA IN WARM SECTOR
TEMPERATURES SHOULD RECOVER WELL WITH MOST AREAS ABOVE AVERAGE.
TONIGHT MORE SIGNIFICANT WAVE CURRENTLY OVER BC WILL DIG INTO THE
NORTHERN ROCKIES. ASSOCIATED SURFACE LOW WILL ORGANIZE OVER THE
WESTERN DAKOTAS WITH SW-NE ORIENTED BOUNDARY SETTING UP LATER IN
THE NIGHT. WILL CONTINUE WITH CHANCE POPS ALONG THIS BOUNDARY.
TEMPERATURES WILL REMAIN MILD OVERNIGHT.
SURFACE LOW WILL LIFT NE SATURDAY AS WAVE APPROACHES. AS IT DOES
ASSOCIATED COLD FRONT WILL FOLLOW LOW AND BE ORIENTED CLOSE TO THE
VALLEY BY PRIME HEATING. CONVECTIVE PARAMETERS FAVORABLE FOR
SEVERE STORMS ALONG AND AHEAD OF THE BOUNDARY SO SEVERE POTENTIAL
WILL HINGE ON JUST WHERE BOUNDARY SETS UP. DEGREE OF CLOUD COVER
WILL GOVERN TEMPERATURES WITH COOLEST READINGS OVER THE FAR NW
WHICH WILL BE BEHIND THE COLD FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
UPPER TROUGH CLOSES OFF SATURDAY NIGHT AS IT LIFTS NE. WRAP
AROUND/DEF ZONE RAIN WILL FOLLOW. AT THIS POINT MODEL GUIDANCE
SUGGESTS THAT THE BEST POTENTIAL FOR RAIN WILL BE OVER THE
NORTHERN 2/3RD OF THE FA.
SUNDAY WILL BE WINDY AND COOLER WITH DEF ZONE PCPN BAND SHIFTING
EAST ACROSS THE FA. COOLER COLUMN AND CLOUDS WILL HOLD
TEMPERATURES DOWN.
RAIN WILL MOVE OUT OF THE NE FA SUNDAY NIGHT. WINDS TO DIMINISH
BUT WILL BE A COOL NIGHT WITH MINIMUM TEMPERATURES IN THE 40S.
LONG WAVE TROUGHS WERE OFF THE WESTERN CANADIAN COAST AND THE GREAT
LAKES WITH A FLAT RIDGE OVER MT. PATTERN AMPLIFIES WITH A TROUGH
OVER THE EASTERN PACIFIC/WESTERN CANADA AND RIDGING INTO THE
NORTHERN PLAINS BY THE END OF THE PERIOD.
GFS AND ECMWF WERE IN BETTER AGREEMENT WITH TODAYS MODEL RUN THROUGH
THE PERIOD. THE ECMWF WAS SLIGHTLY FASTER THAN THE GFS. THE ECMWF
WAS VACILLATING AROUND A POINT WHILE THE GFS WAS TRENDING SLOWER
OVER THE LAST COUPLE MODEL RUNS.
NO CHANGE TO HIGH TEMPS FOR MON. HIGH TEMPS WERE DECREASED A DEGREE
OR TWO FOR TUE AND WED, AND INCREASED ZERO TO FOUR DEGREES FOR THU
FORM YESTERDAYS PACKAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1210 PM CDT FRI AUG 21 2015
VFR CONDITIONS FCST TO CONTINUE THROUGH THE PERIOD WITH MAINLY MID
AND HIGH LEVEL CIGS. SFC HIGH PRESSURE WILL RETREAT THIS AFTERNOON
AND EVENING...WITH WINDS BECOMING SOUTHERLY FROM 10 TO 20 MPH AHEAD
OF DEVELOPING LOW PRESSURE MOVG ACROSS THE HIGH PLAINS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...HOPPES/VOELKER
AVIATION...HOPKINS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 AM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 955 AM CDT FRI AUG 21 2015
WE ARE GETTING SMOKE INTO THE REGION...AND THIS WILL IMPACT HIGH
TEMPS SOME TODAY. WE WILL LOWER TEMPS TODAY ABOUT 2-4 DEGREES
GIVEN THICKER HIGH LEVEL SMOKE. OTHERWISE...NO OTHER MAJOR CHANGES
NEEDED.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
FORECAST CHALLENGES WILL BE SEVERE THREAT SATURDAY AS WELL AS RAINFALL
AMOUNTS MAINLY THIS WEEKEND AND TEMPERATURES/WIND. MODELS OVERALL
IN PRETTY GOOD AGREEMENT THROUGH THE PERIOD AND WILL USE MODEL
BLEND.
CURRENT SHORTWAVE PROPAGATING EAST ACROSS SW MB INTO ONTARIO THIS
MORNING. ASSOCIATED AREA OF SHRA/ISOLD T ON NOSE OF LOW LEVEL JET
IN WARM ADVECTION ZONE. ALTHOUGH INSTABILITY AND CAPE MINIMAL A
FEW LIGHTNING STRIKES OCCURRING. CURRENT HRRR WEAKENS PCPN
THROUGH THE MORNING AND OUT OF THE FA BY MID MORNING. WILL
MAINTAIN LOW POPS BASED ON SHORT TERM MODEL GUIDANCE. THE
REMAINDER OF THIS AFTERNOON SHOULD REMAIN DRY. CONTINUED WARM
ADVECTION WILL SET UP WARM FRONTAL BOUNDARY ALONG THE
INTERNATIONAL BORDER BY THIS EVENING. WITH FA IN WARM SECTOR
TEMPERATURES SHOULD RECOVER WELL WITH MOST AREAS ABOVE AVERAGE.
TONIGHT MORE SIGNIFICANT WAVE CURRENTLY OVER BC WILL DIG INTO THE
NORTHERN ROCKIES. ASSOCIATED SURFACE LOW WILL ORGANIZE OVER THE
WESTERN DAKOTAS WITH SW-NE ORIENTED BOUNDARY SETTING UP LATER IN
THE NIGHT. WILL CONTINUE WITH CHANCE POPS ALONG THIS BOUNDARY.
TEMPERATURES WILL REMAIN MILD OVERNIGHT.
SURFACE LOW WILL LIFT NE SATURDAY AS WAVE APPROACHES. AS IT DOES
ASSOCIATED COLD FRONT WILL FOLLOW LOW AND BE ORIENTED CLOSE TO THE
VALLEY BY PRIME HEATING. CONVECTIVE PARAMETERS FAVORABLE FOR
SEVERE STORMS ALONG AND AHEAD OF THE BOUNDARY SO SEVERE POTENTIAL
WILL HINGE ON JUST WHERE BOUNDARY SETS UP. DEGREE OF CLOUD COVER
WILL GOVERN TEMPERATURES WITH COOLEST READINGS OVER THE FAR NW
WHICH WILL BE BEHIND THE COLD FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
UPPER TROUGH CLOSES OFF SATURDAY NIGHT AS IT LIFTS NE. WRAP
AROUND/DEF ZONE RAIN WILL FOLLOW. AT THIS POINT MODEL GUIDANCE
SUGGESTS THAT THE BEST POTENTIAL FOR RAIN WILL BE OVER THE
NORTHERN 2/3RD OF THE FA.
SUNDAY WILL BE WINDY AND COOLER WITH DEF ZONE PCPN BAND SHIFTING
EAST ACROSS THE FA. COOLER COLUMN AND CLOUDS WILL HOLD
TEMPERATURES DOWN.
RAIN WILL MOVE OUT OF THE NE FA SUNDAY NIGHT. WINDS TO DIMINISH
BUT WILL BE A COOL NIGHT WITH MINIMUM TEMPERATURES IN THE 40S.
LONG WAVE TROUGHS WERE OFF THE WESTERN CANADIAN COAST AND THE GREAT
LAKES WITH A FLAT RIDGE OVER MT. PATTERN AMPLIFIES WITH A TROUGH
OVER THE EASTERN PACIFIC/WESTERN CANADA AND RIDGING INTO THE
NORTHERN PLAINS BY THE END OF THE PERIOD.
GFS AND ECMWF WERE IN BETTER AGREEMENT WITH TODAYS MODEL RUN THROUGH
THE PERIOD. THE ECMWF WAS SLIGHTLY FASTER THAN THE GFS. THE ECMWF
WAS VACILLATING AROUND A POINT WHILE THE GFS WAS TRENDING SLOWER
OVER THE LAST COUPLE MODEL RUNS.
NO CHANGE TO HIGH TEMPS FOR MON. HIGH TEMPS WERE DECREASED A DEGREE
OR TWO FOR TUE AND WED, AND INCREASED ZERO TO FOUR DEGREES FOR THU
FORM YESTERDAYS PACKAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 639 AM CDT FRI AUG 21 2015
CIGS ASSOCIATED WITH SHRA OVER THE NORTHERN FA REMAIN IN THE MID
LEVELS WITH CLEARING REACHING THE NORTHERN VALLEY. EXPECT MID
LEVEL CIGS TO EXIT THE FA BY LATE MORNING WITH VFR CONDITIONS
CONTINUING THROUGH THE REMAINDER OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...HOPPES/VOELKER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
644 AM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 639 AM CDT FRI AUG 21 2015
SHRA SHRINKING IN COVERAGE AND CONFINED TO NW MN EAST OF NORTHERN
VALLEY. NO LTG STRIKES IN THE LAST FEW HOURS SO TRANSITIONED BACK
TO SHRA. MADE SOME MINOR POP ADJUSTMENTS THROUGH THE REMAINDER OF
THE MORNING WITH NO OTHER FORECAST CHANGES.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
FORECAST CHALLENGES WILL BE SEVERE THREAT SATURDAY AS WELL AS RAINFALL
AMOUNTS MAINLY THIS WEEKEND AND TEMPERATURES/WIND. MODELS OVERALL
IN PRETTY GOOD AGREEMENT THROUGH THE PERIOD AND WILL USE MODEL
BLEND.
CURRENT SHORTWAVE PROPAGATING EAST ACROSS SW MB INTO ONTARIO THIS
MORNING. ASSOCIATED AREA OF SHRA/ISOLD T ON NOSE OF LOW LEVEL JET
IN WARM ADVECTION ZONE. ALTHOUGH INSTABILITY AND CAPE MINIMAL A
FEW LIGHTNING STRIKES OCCURRING. CURRENT HRRR WEAKENS PCPN
THROUGH THE MORNING AND OUT OF THE FA BY MID MORNING. WILL
MAINTAIN LOW POPS BASED ON SHORT TERM MODEL GUIDANCE. THE
REMAINDER OF THIS AFTERNOON SHOULD REMAIN DRY. CONTINUED WARM
ADVECTION WILL SET UP WARM FRONTAL BOUNDARY ALONG THE
INTERNATIONAL BORDER BY THIS EVENING. WITH FA IN WARM SECTOR
TEMPERATURES SHOULD RECOVER WELL WITH MOST AREAS ABOVE AVERAGE.
TONIGHT MORE SIGNIFICANT WAVE CURRENTLY OVER BC WILL DIG INTO THE
NORTHERN ROCKIES. ASSOCIATED SURFACE LOW WILL ORGANIZE OVER THE
WESTERN DAKOTAS WITH SW-NE ORIENTED BOUNDARY SETTING UP LATER IN
THE NIGHT. WILL CONTINUE WITH CHANCE POPS ALONG THIS BOUNDARY.
TEMPERATURES WILL REMAIN MILD OVERNIGHT.
SURFACE LOW WILL LIFT NE SATURDAY AS WAVE APPROACHES. AS IT DOES
ASSOCIATED COLD FRONT WILL FOLLOW LOW AND BE ORIENTED CLOSE TO THE
VALLEY BY PRIME HEATING. CONVECTIVE PARAMETERS FAVORABLE FOR
SEVERE STORMS ALONG AND AHEAD OF THE BOUNDARY SO SEVERE POTENTIAL
WILL HINGE ON JUST WHERE BOUNDARY SETS UP. DEGREE OF CLOUD COVER
WILL GOVERN TEMPERATURES WITH COOLEST READINGS OVER THE FAR NW
WHICH WILL BE BEHIND THE COLD FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
UPPER TROUGH CLOSES OFF SATURDAY NIGHT AS IT LIFTS NE. WRAP
AROUND/DEF ZONE RAIN WILL FOLLOW. AT THIS POINT MODEL GUIDANCE
SUGGESTS THAT THE BEST POTENTIAL FOR RAIN WILL BE OVER THE
NORTHERN 2/3RD OF THE FA.
SUNDAY WILL BE WINDY AND COOLER WITH DEF ZONE PCPN BAND SHIFTING
EAST ACROSS THE FA. COOLER COLUMN AND CLOUDS WILL HOLD
TEMPERATURES DOWN.
RAIN WILL MOVE OUT OF THE NE FA SUNDAY NIGHT. WINDS TO DIMINISH
BUT WILL BE A COOL NIGHT WITH MINIMUM TEMPERATURES IN THE 40S.
LONG WAVE TROUGHS WERE OFF THE WESTERN CANADIAN COAST AND THE GREAT
LAKES WITH A FLAT RIDGE OVER MT. PATTERN AMPLIFIES WITH A TROUGH
OVER THE EASTERN PACIFIC/WESTERN CANADA AND RIDGING INTO THE
NORTHERN PLAINS BY THE END OF THE PERIOD.
GFS AND ECMWF WERE IN BETTER AGREEMENT WITH TODAYS MODEL RUN THROUGH
THE PERIOD. THE ECMWF WAS SLIGHTLY FASTER THAN THE GFS. THE ECMWF
WAS VACILLATING AROUND A POINT WHILE THE GFS WAS TRENDING SLOWER
OVER THE LAST COUPLE MODEL RUNS.
NO CHANGE TO HIGH TEMPS FOR MON. HIGH TEMPS WERE DECREASED A DEGREE
OR TWO FOR TUE AND WED, AND INCREASED ZERO TO FOUR DEGREES FOR THU
FORM YESTERDAYS PACKAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 639 AM CDT FRI AUG 21 2015
CIGS ASSOCIATED WITH SHRA OVER THE NORTHERN FA REMAIN IN THE MID
LEVELS WITH CLEARING REACHING THE NORTHERN VALLEY. EXPECT MID
LEVEL CIGS TO EXIT THE FA BY LATE MORNING WITH VFR CONDITIONS
CONTINUING THROUGH THE REMAINDER OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...VOELKER
LONG TERM...HOPPES/VOELKER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
352 AM CDT FRI AUG 21 2015
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
FORECAST CHALLENGES WILL BE SEVERE THREAT SATURDAY AS WELL AS RAINFALL
AMOUNTS MAINLY THIS WEEKEND AND TEMPERATURES/WIND. MODELS OVERALL
IN PRETTY GOOD AGREEMENT THROUGH THE PERIOD AND WILL USE MODEL
BLEND.
CURRENT SHORTWAVE PROPAGATING EAST ACROSS SW MB INTO ONTARIO THIS
MORNING. ASSOCIATED AREA OF SHRA/ISOLD T ON NOSE OF LOW LEVEL JET
IN WARM ADVECTION ZONE. ALTHOUGH INSTABILITY AND CAPE MINIMAL A
FEW LIGHTNING STRIKES OCCURRING. CURRENT HRRR WEAKENS PCPN
THROUGH THE MORNING AND OUT OF THE FA BY MID MORNING. WILL
MAINTAIN LOW POPS BASED ON SHORT TERM MODEL GUIDANCE. THE
REMAINDER OF THIS AFTERNOON SHOULD REMAIN DRY. CONTINUED WARM
ADVECTION WILL SET UP WARM FRONTAL BOUNDARY ALONG THE
INTERNATIONAL BORDER BY THIS EVENING. WITH FA IN WARM SECTOR
TEMPERATURES SHOULD RECOVER WELL WITH MOST AREAS ABOVE AVERAGE.
TONIGHT MORE SIGNIFICANT WAVE CURRENTLY OVER BC WILL DIG INTO THE
NORTHERN ROCKIES. ASSOCIATED SURFACE LOW WILL ORGANIZE OVER THE
WESTERN DAKOTAS WITH SW-NE ORIENTED BOUNDARY SETTING UP LATER IN
THE NIGHT. WILL CONTINUE WITH CHANCE POPS ALONG THIS BOUNDARY.
TEMPERATURES WILL REMAIN MILD OVERNIGHT.
SURFACE LOW WILL LIFT NE SATURDAY AS WAVE APPROACHES. AS IT DOES
ASSOCIATED COLD FRONT WILL FOLLOW LOW AND BE ORIENTED CLOSE TO THE
VALLEY BY PRIME HEATING. CONVECTIVE PARAMETERS FAVORABLE FOR
SEVERE STORMS ALONG AND AHEAD OF THE BOUNDARY SO SEVERE POTENTIAL
WILL HINGE ON JUST WHERE BOUNDARY SETS UP. DEGREE OF CLOUD COVER
WILL GOVERN TEMPERATURES WITH COOLEST READINGS OVER THE FAR NW
WHICH WILL BE BEHIND THE COLD FRONT.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 21 2015
UPPER TROUGH CLOSES OFF SATURDAY NIGHT AS IT LIFTS NE. WRAP
AROUND/DEF ZONE RAIN WILL FOLLOW. AT THIS POINT MODEL GUIDANCE
SUGGESTS THAT THE BEST POTENTIAL FOR RAIN WILL BE OVER THE
NORTHERN 2/3RD OF THE FA.
SUNDAY WILL BE WINDY AND COOLER WITH DEF ZONE PCPN BAND SHIFTING
EAST ACROSS THE FA. COOLER COLUMN AND CLOUDS WILL HOLD
TEMPERATURES DOWN.
RAIN WILL MOVE OUT OF THE NE FA SUNDAY NIGHT. WINDS TO DIMINISH
BUT WILL BE A COOL NIGHT WITH MINIMUM TEMPERATURES IN THE 40S.
LONG WAVE TROUGHS WERE OFF THE WESTERN CANADIAN COAST AND THE GREAT
LAKES WITH A FLAT RIDGE OVER MT. PATTERN AMPLIFIES WITH A TROUGH
OVER THE EASTERN PACIFIC/WESTERN CANADA AND RIDGING INTO THE
NORTHERN PLAINS BY THE END OF THE PERIOD.
GFS AND ECMWF WERE IN BETTER AGREEMENT WITH TODAYS MODEL RUN THROUGH
THE PERIOD. THE ECMWF WAS SLIGHTLY FASTER THAN THE GFS. THE ECMWF
WAS VACILLATING AROUND A POINT WHILE THE GFS WAS TRENDING SLOWER
OVER THE LAST COUPLE MODEL RUNS.
NO CHANGE TO HIGH TEMPS FOR MON. HIGH TEMPS WERE DECREASED A DEGREE
OR TWO FOR TUE AND WED, AND INCREASED ZERO TO FOUR DEGREES FOR THU
FORM YESTERDAYS PACKAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1149 PM CDT THU AUG 20 2015
SCATTERED MID AND HIGH LEVEL CLOUDS MAINLY NE ND/NW MN WITH SHORT
WAVE MOVING THRU MANITOBA OVERNIGHT INTO FRIDAY MORNING. SCATTERED
CIRRUS IN SE ND/WCNTRL MN. SOUTH WINDS 8 TO 15 KTS WITH A FEW
GUSTS AT TIMES THRU FRIDAY....PICKING UP FRI EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...VOELKER
LONG TERM...HOPPES/VOELKER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
146 AM EDT FRI AUG 21 2015
.SYNOPSIS...
A COLD FRONT HAS MOVED EAST OF THE AREA WITH COOLER AND DRIER AIR
SETTLING OVER THE AREA BEHIND IT. A SURFACE AREA OF HIGH PRESSURE
TO OUR WEST WILL MOVE INTO THE AREA FRIDAY AND LINGER THROUGH THE
WEEKEND. THE NEXT CHANCE FOR RAIN WILL BE SUNDAY NIGHT INTO MONDAY
WHEN A COLD FRONT ARRIVES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPPER TROUGH WILL LIFT ACROSS THE CENTRAL GREAT LAKES OVERNIGHT.
THERE WILL BE SOME INCREASED LIFT OVER THE LAKE AS THE COOLER AIR
ARRIVES IN THE WAKE OF THE TROUGH. THERE COULD BE A FEW SHOWERS
THAT DEVELOP FROM THE ERIE AREA NORTHWARD INTO NY STATE. HOWEVER
THE MAIN IMPACT WILL BE AN INCREASE OF CLOUD COVER FROM CLEVELAND
TO ERIE THROUGH THE EVENING.
PREVIOUS DISCUSSION...
THE WATER VAPOR SATELLITE IMAGERY DISTINCTLY DEFINES THE TROUGH
OVER THE UPPER LAKES AND THE DRIER AIR FILTERING INTO THE OHIO
VALLEY ALOFT. AT THE SURFACE HIGH PRESSURE OVER THE PLAINS WILL
SLIDE EAST OVERNIGHT AND LINGER OVER THE AIR INTO THE WEEKEND. DEW
POINTS HAVE DROPPED 10-15F SINCE THIS MORNING...WHICH WILL SUPPORT
NOTABLY COOLER TEMPERATURES OVERNIGHT. NCAR ENSEMBLES ALONG WITH
THE RUC ARE SUGGESTING DEW POINTS INTO THE UPPER 40S
OVERNIGHT...HOWEVER NOT SEEING ANY 40S UPSTREAM OR NEAR THE AREA
DESPITE A FAIR AMOUNT OF AFTERNOON MIXING. WITH DEW POINTS IN THE
LOW TO MID 50S...MOSTLY CLEAR SKIES...AND WINDS TAPERING OFF AFTER
DARK...WILL KEEP TEMPERATURES IN THE LOW TO MID 50S OVERNIGHT.
ONLY FLY IN THE OINTMENT WILL BE ANY POTENTIAL DEVELOPMENT OVER
THE LAKE AS THE H850 AND WATER TEMPERATURES DIFFER BY ABOUT 14C.
THE BEST CHANCE FOR ANYTHING TO DEVELOP WILL BE BETWEEN 06 AND 15Z
FRI...BUT AT THIS TIME WILL KEEP ONLY ISOLATED RAIN OVER THE
EASTERN PORTIONS OF THE LAKE AND NOT INTO ERIE PA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS THE HIGH BUILDS OVERHEAD FRIDAY ANY LAKE ACTIVITY WILL BE SHUT
DOWN BY THE DRIER AIR AND THE SINKING INVERSION. LOOK FOR SUNNY
SKIES AND TEMPERATURES IN THE 70S. THE HIGH WILL SHIFT EAST ON
SATURDAY WHICH WILL SUPPORT SOME WEAK RETURN FLOW WHICH WILL
CONTINUE INTO SUNDAY. MEANWHILE THE NW FLOW ALOFT WILL TURN TO
THE SW WITH WARMER TEMPERATURES ADVECTING IN WITH H850 REACHING
12C WHICH WILL TRANSLATE INTO GRADUAL WARMING AT THE SURFACE. THE
NEXT CHANCE FOR PRECIPITATION WILL BE ASSOCIATED WITH ANOTHER MID
LEVEL TROUGH MOVING OUT OF THE ROCKIES. AN ASSOCIATED COLD FRONT
WILL REACH THE AREA SUNDAY NIGHT AND WITH WARMER/MOIST AIR AND AN
INCREASE IN THE LOW LEVEL JET CAN`T RULE OUT SOME THUNDERSTORMS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
A COLD FRONT WILL BE MOVING THROUGH THE EASTERN EDGE OF THE AREA
MONDAY MORNING ALONG WITH A FEW LINGERING SHOWERS. COLD ADVECTION
WILL OVERSPREAD THE REGION IN THE WAKE OF THE COLD FRONT. THE
UPPER AIR PATTERN WILL EXHIBIT A LONG WAVE TROUGH OVER ONTARIO
EARLY IN THE EXTENDED WITH THIS FEATURE LIFTING FARTHER NORTH AND
ALLOWING A MORE ZONAL FLOW TO DEVELOP. BELOW NORMAL TEMPERATURES
ARE EXPECTED WITH GENERALLY DRY CONDITIONS BUT A FEW SHOWERS ARE
POSSIBLE WEDNESDAY AFTERNOON AND EVENING MAINLY OVER NORTHWEST PA
WHERE A MOIST CYCLONIC FLOW ALOFT ALONG WITH WELL MIXED ADIABATIC
CONDITIONS ARE EXPECTED.
CONDITIONS WILL WARM ON THURSDAY AND FRIDAY AS THE 850 MB
TEMPERATURES RISE TO MORE SEASONAL LEVELS AND MORE SUNSHINE
PREVAILS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
SYNOPTIC AND LAKE EFFECT CLOUDS PRIMARILY AROUND 6K FEET WILL
PERIODICALLY PASS OVER SITES NEAREST TO THE LAKESHORE. KERI COULD
BRIEFLY SEE A 3.5K FOOT CIG DEVELOP BY DAYBREAK. CLOUDS WILL
BEGIN TO BREAK UP FRIDAY AFTERNOON AS HIGH PRESSURE MOVES IN FROM
THE SW. DIURNAL CU IS THEN LIKELY TO DEVELOP ACROSS NEOH AND NWPA.
THE WIND WILL GRADUALLY DIMINISH THROUGH THE DAY AS THE HIGH
APPROACHES. FRIDAY NIGHT THE WIND WILL BECOME LIGHT AND VARIABLE
IN THE EAST WITH THE HIGH OVERHEAD...AND SOUTHERLY IN THE WEST.
OUTLOOK...NON VFR CONDITIONS POSSIBLE SUNDAY NIGHT WITH THE PASSAGE
OF A COLD FRONT AND POSSIBLE SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SMALL CRAFT CONDITIONS PREVAIL IN THE WAKE OF THE COLD
FRONT THAT HAS SWEPT EAST THROUGH THE REGION. A RATHER STRONG
PRESSURE GRADIENT FOR SUMMER ALONG WITH COLD ADVECTION ALOFT WILL
ALLOW MIXING OF HIGHER MOMENTUM AIR TO THE SURFACE. WITH 850 MB
TEMPERATURES EXPECTED TO DROP TO NEAR 10C AND LAKE SURFACE
TEMPERATURES FROM 22-24C... NEAR ADIABATIC LAPSE RATE IS EXPECTED
OVER THE LAKE WHICH WILL PERMIT DEEP MIXING AND STRONGER WINDS TO
PREVAIL. WILL CONTINUE WITH SMALL CRAFT ADVISORY THROUGH 08Z EAST
OF THE ISLANDS. IT MAY NEED TO BE EXTENDED SLIGHTLY LONGER IN THE
EASTERN HALF OF THE LAKE WHERE THE STRONGER PRESSURE GRADIENT WILL
LINGER.
HIGH PRESSURE WILL GRADUALLY BUILD SOUTH OF THE LAKE FRIDAY AND THEN
REMAIN OVER THE REGION INTO THE WEEKEND. WINDS WILL CONTINUE TO
DIMINISH FRIDAY AND BE LIGHT ON SATURDAY. SOUTHERLY WINDS WILL
INCREASE ON SUNDAY AS ANOTHER FRONTAL BOUNDARY APPROACHES WITH ITS
PASSAGE EXPECTED SUNDAY NIGHT. SMALL CRAFT CONDITIONS WILL LIKELY
DEVELOP IN THE WAKE OF THAT FRONTAL PASSAGE GIVEN THE COOLING ALOFT
DOWN TO JUST BELOW 10C AT 850 MB. WINDS WILL DECREASE ON TUESDAY AS
HIGH PRESSURE BUILDS INTO THE REGION.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
LEZ144>149.
&&
$$
SYNOPSIS...JAMISON
NEAR TERM...JAMISON/MULLEN
SHORT TERM...JAMISON
LONG TERM...LAPLANTE
AVIATION...MAYERS
MARINE...ADAMS/LAPLANTE
AREA FORECAST DISCUSSION
NWS NORMAN OK
600 PM CDT FRI AUG 21 2015
.AVIATION...
EXPECT TO SEE SOME SHWR/TSTMS IMPACT MOST SITES LATER THIS EVENING
WITH ASSOCAITED MVFR CONDITIONS. WITH VFR RETURNING OVERNIGHT AND
CONT THROUGH THE DAY ON SATURDAY. MUCH LIKE TODAY... SOUTH WINDS
WILL INCREASE DURING THE DAY SATURDAY WITH GUSTS OF 20 TO 25KTS
EXPECTED BY LATE MORNING INTO THE AFTN HOURS.
30
&&
.PREV DISCUSSION... /ISSUED 218 PM CDT FRI AUG 21 2015/
.DISCUSSION...
PRIMARY FORECAST CONCERN LIES WITH THUNDERSTORM CHANCES THIS EVENING
AND OVERNIGHT.
CURRENTLY... STOUT MID-LEVEL SHORT WAVE CONTINUES TO DIG ACROSS NERN
NM/SERN CO INTO THE NRN PANHANDLES. AHEAD OF THIS WAVE... WAA HAS
INCREASED ACROSS WRN N TX INTO WRN OK... IN RESPONSE... LL CLOUDS
CONTINUE TO DISSIPATE ACROSS NRN TX/SRN INTO CENTRAL OK. FROM 15Z
FORWARD... EACH PROGRESSIVE RUN OF THE HRRR HAS BECOME MORE
AGGRESSIVE WITH CONVECTIVE DEVELOPMENT OVER THE ERN PANHANDLES AND
ACROSS WRN OK/WRN N TX INTO CENTRAL/SOUTH CENTRAL OK OVERNIGHT.
TIMING HAS BEEN RELATIVELY CONSISTENT FROM RUN TO RUN... AND SIMILAR
TO TRADITIONAL GUIDANCE FROM THE NAM/GFS/ECMWF. WITH THAT SAID...
CURRENT EXPECTATIONS IS FOR INITIAL CONVECTION TO DEVELOP OVER THE
NRN TX PH/OK PH BETWEEN 21-23Z (4-6 PM CDT)... MOVING E/SE INTO WRN
OK THROUGH 23-01Z (6-8 PM CDT). WITH CLEARING SKIES... INSTABILITY
WILL INCREASE ACROSS THE WRN TX PH/WRN OK... 1000 TO 1500 J/KG ALONG
WITH 30 TO 40KTS OF DEEP LAYER SHEAR. ASCENT FOR FORCING IS CONFINED
TO THE MID-LEVELS... 850/700MB... THEREFORE... EXPECT CONVECTION TO
BE ELEVATED... AND BUFR SOUNDINGS SUPPORT THIS... WITH LCLS BETWEEN
2000 TO 3000 FT AGL. PRIMARY CONCERN WILL BE LARGE HAIL... POSSIBLY
UP TO GOLF BALL SIZE... DAMAGING WINDS UP TO 60 MPH AND FREQUENT
LIGHTNING. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE... WITH PWATS IN
THE 75TH PERCENTILE... 1.40-1.60IN... HOWEVER... THE MID-LEVEL SHORT
WAVE IS MOVING AT A DECENT CLIP... SO HYDRO IMPACTS SHOULD BE
MINIMAL AS STORMS WILL BE MOVING OUT QUICKLY THROUGH THE EARLY
MORNING HOURS OF SATURDAY.
SATURDAY MORNING... THE CHANCE FOR STRONG TO SEVERE STORMS WILL WANE
QUICKLY THROUGH MIDNIGHT... WITH SCATTERED CONVECTION CONTINUING
ACROSS CENTRAL INTO ERN OK THROUGH DAWN. MOST OF THE REMAINING
STORMS WILL STILL RETAIN THE ABILITY TO PRODUCE 40 MPH GUSTS AND
FREQUENT LIGHTNING.
LATE SATURDAY MORNING AND AFTERNOON... SOME LINGERING SHOWERS MAY
HANG AROUND... BUT DRY WEATHER CAN BE EXPECTED AS WAA INCREASES
AGAIN AHEAD OF COLD FRONT THAT WILL BE MOVING IN FROM THE NW DURING
THE AFTN IN RESPONSE TO A STRONG H500 SHORT WAVE SWINGING ACROSS THE
NRN PLAINS. THIS FRONT WILL DROP S/SE INTO THE SRN PLAINS SAT NIGHT
THROUGH SUN MORNING... BRINGING A GOOD CHANCE OF PRECIP TO THE
REGION OVERNIGHT AS PWATS WILL RANGE FROM 1.5 TO 1.70IN AHEAD OF THE
FRONT OVERNIGHT. GUIDANCE REMAINS IN DECENT AGREEMENT... WITH THE
FRONT MOVING FAIRLY QUICKLY... PUSHING TO THE RED RIVER THROUGH
EARLY/MID MORNING. PRECIP AMOUNTS BETWEEN 0.50 AND 1.00 IN... WITH
THE BEST CHANCES ACROSS NRN OK OVERNIGHT. NO SEVERE WEATHER IS
EXPECTED AT THIS TIME... ALTHOUGH A FEW STRONGER STORMS MAY BE
CAPABLE OF 40 TO 45 MPH GUSTS.
AFTER SUNDAY... THE H500 RIDGE WILL CONTINUE TO BUILD OVER THE SWRN
U.S... WITH GOOD CONSISTENCY BETWEEN RUNS OVER THE PAST FEW DAYS.
THIS WILL BODE WELL FOR TEMPS ACROSS THE REGION... KEEPING THE SRN
PLAINS NEAR NORMAL... WITH HIGHS IN THE UPPER 80S/LOWER 90S INTO
NEXT WEEK. HOWEVER... RESIDING UNDER THE ERN EDGE OF THE RIDGE...
THERE WILL BE A NEAR DAILY CHANCE OF ISOLATED TO SCATTERED
THUNDERSTORMS ACROSS THE REGION IN RESPONSE TO A SERIES OF SHORT
WAVES TRAVERSING THE LARGER RIDGE THROUGH THE END OF NEXT WEEK. THE
BEST CHANCE FOR PRECIP NEXT WEEK WILL BE MON INTO TUE AS THE WEEKEND
FRONT LIFTS TOWARD THE RED RIVER AS A WEAK WARM FRONT... BRINGING A
CHANCE OF SHOWERS AND THUNDERSTORMS TO TEXOMA AND WRN AND CENTRAL OK.
JTK
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 71 92 71 84 / 40 10 60 30
HOBART OK 71 96 72 85 / 60 10 40 30
WICHITA FALLS TX 74 97 75 93 / 40 10 20 40
GAGE OK 69 94 65 80 / 60 0 60 20
PONCA CITY OK 72 91 67 82 / 40 20 70 10
DURANT OK 73 94 75 93 / 40 10 10 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
218 PM CDT FRI AUG 21 2015
.DISCUSSION...
PRIMARY FORECAST CONCERN LIES WITH THUNDERSTORM CHANCES THIS EVENING
AND OVERNIGHT.
CURRENTLY... STOUT MID-LEVEL SHORT WAVE CONTINUES TO DIG ACROSS NERN
NM/SERN CO INTO THE NRN PANHANDLES. AHEAD OF THIS WAVE... WAA HAS
INCREASED ACROSS WRN N TX INTO WRN OK... IN RESPONSE... LL CLOUDS
CONTINUE TO DISSIPATE ACROSS NRN TX/SRN INTO CENTRAL OK. FROM 15Z
FORWARD... EACH PROGRESSIVE RUN OF THE HRRR HAS BECOME MORE
AGGRESSIVE WITH CONVECTIVE DEVELOPMENT OVER THE ERN PANHANDLES AND
ACROSS WRN OK/WRN N TX INTO CENTRAL/SOUTH CENTRAL OK OVERNIGHT.
TIMING HAS BEEN RELATIVELY CONSISTENT FROM RUN TO RUN... AND SIMILAR
TO TRADITIONAL GUIDANCE FROM THE NAM/GFS/ECMWF. WITH THAT SAID...
CURRENT EXPECTATIONS IS FOR INITIAL CONVECTION TO DEVELOP OVER THE
NRN TX PH/OK PH BETWEEN 21-23Z (4-6 PM CDT)... MOVING E/SE INTO WRN
OK THROUGH 23-01Z (6-8 PM CDT). WITH CLEARING SKIES... INSTABILITY
WILL INCREASE ACROSS THE WRN TX PH/WRN OK... 1000 TO 1500 J/KG ALONG
WITH 30 TO 40KTS OF DEEP LAYER SHEAR. ASCENT FOR FORCING IS CONFINED
TO THE MID-LEVELS... 850/700MB... THEREFORE... EXPECT CONVECTION TO
BE ELEVATED... AND BUFR SOUNDINGS SUPPORT THIS... WITH LCLS BETWEEN
2000 TO 3000 FT AGL. PRIMARY CONCERN WILL BE LARGE HAIL... POSSIBLY
UP TO GOLF BALL SIZE... DAMAGING WINDS UP TO 60 MPH AND FREQUENT
LIGHTNING. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE... WITH PWATS IN
THE 75TH PERCENTILE... 1.40-1.60IN... HOWEVER... THE MID-LEVEL SHORT
WAVE IS MOVING AT A DECENT CLIP... SO HYDRO IMPACTS SHOULD BE
MINIMAL AS STORMS WILL BE MOVING OUT QUICKLY THROUGH THE EARLY
MORNING HOURS OF SATURDAY.
SATURDAY MORNING... THE CHANCE FOR STRONG TO SEVERE STORMS WILL WANE
QUICKLY THROUGH MIDNIGHT... WITH SCATTERED CONVECTION CONTINUING
ACROSS CENTRAL INTO ERN OK THROUGH DAWN. MOST OF THE REMAINING
STORMS WILL STILL RETAIN THE ABILITY TO PRODUCE 40 MPH GUSTS AND
FREQUENT LIGHTNING.
LATE SATURDAY MORNING AND AFTERNOON... SOME LINGERING SHOWERS MAY
HANG AROUND... BUT DRY WEATHER CAN BE EXPECTED AS WAA INCREASES
AGAIN AHEAD OF COLD FRONT THAT WILL BE MOVING IN FROM THE NW DURING
THE AFTN IN RESPONSE TO A STRONG H500 SHORT WAVE SWINGING ACROSS THE
NRN PLAINS. THIS FRONT WILL DROP S/SE INTO THE SRN PLAINS SAT NIGHT
THROUGH SUN MORNING... BRINGING A GOOD CHANCE OF PRECIP TO THE
REGION OVERNIGHT AS PWATS WILL RANGE FROM 1.5 TO 1.70IN AHEAD OF THE
FRONT OVERNIGHT. GUIDANCE REMAINS IN DECENT AGREEMENT... WITH THE
FRONT MOVING FAIRLY QUICKLY... PUSHING TO THE RED RIVER THROUGH
EARLY/MID MORNING. PRECIP AMOUNTS BETWEEN 0.50 AND 1.00 IN... WITH
THE BEST CHANCES ACROSS NRN OK OVERNIGHT. NO SEVERE WEATHER IS
EXPECTED AT THIS TIME... ALTHOUGH A FEW STRONGER STORMS MAY BE
CAPABLE OF 40 TO 45 MPH GUSTS.
AFTER SUNDAY... THE H500 RIDGE WILL CONTINUE TO BUILD OVER THE SWRN
U.S... WITH GOOD CONSISTENCY BETWEEN RUNS OVER THE PAST FEW DAYS.
THIS WILL BODE WELL FOR TEMPS ACROSS THE REGION... KEEPING THE SRN
PLAINS NEAR NORMAL... WITH HIGHS IN THE UPPER 80S/LOWER 90S INTO
NEXT WEEK. HOWEVER... RESIDING UNDER THE ERN EDGE OF THE RIDGE...
THERE WILL BE A NEAR DAILY CHANCE OF ISOLATED TO SCATTERED
THUNDERSTORMS ACROSS THE REGION IN RESPONSE TO A SERIES OF SHORT
WAVES TRAVERSING THE LARGER RIDGE THROUGH THE END OF NEXT WEEK. THE
BEST CHANCE FOR PRECIP NEXT WEEK WILL BE MON INTO TUE AS THE WEEKEND
FRONT LIFTS TOWARD THE RED RIVER AS A WEAK WARM FRONT... BRINGING A
CHANCE OF SHOWERS AND THUNDERSTORMS TO TEXOMA AND WRN AND CENTRAL OK.
JTK
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 71 92 71 84 / 40 10 60 30
HOBART OK 71 96 72 85 / 60 10 40 30
WICHITA FALLS TX 74 97 75 93 / 40 10 20 40
GAGE OK 69 94 65 80 / 60 0 60 20
PONCA CITY OK 72 91 67 82 / 40 20 70 10
DURANT OK 73 94 75 93 / 40 10 10 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
124 AM EDT FRI AUG 21 2015
.SYNOPSIS...
HIGH PRESSURE OVER THE OHIO VALLEY WILL BUILD EAST INTO
PENNSYLVANIA TODAY AND REMAIN OVER THE REGION THROUGH THE UPCOMING
WEEKEND. A COLD FRONT WILL MOVE THROUGH THE AREA ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
WET GROUND...CLEARING SKIES AND A LIGHT WIND PROMOTING PATCHY
DENSE FOG ACROSS CENTRAL PA EARLY THIS AM. 11-3.9U SATL IMAGERY
SHOWING THE FOG IS MOST PREVALENT ACROSS THE EASTERN HALF OF THE
STATE...WHERE THE HEAVIEST RAIN FELL. NEAR TERM MDL SFC RH FIELDS
IMPLY THIS WILL REMAIN THE CASE THROUGH DAWN.
TEMPS ON TRACK TO BOTTOM OUT FROM THE L50S ACROSS THE NW
MTNS...TO THE L-M 60S IN THE FAR SE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
THE FRONT IS EXPECTED TO SLOW AND EVENTUALLY STALL OUT AS IT
NEARS THE MID ATLC COAST...IN RESPONSE TO STRONG N. ATLC UPPER
RIDGE AND UPPER/NON-TROPICAL LOW NEAR BERMUDA. THERE IS SOME
CONCERN THAT THE EASTERN MOST PORTIONS OF OUR FORECAST ZONES
COULD SEE LINGERING CLOUDS AND A SHOWER....BUT I USED THE HRRR TO
DOWNPLAY THIS SCENARIO AS LOW PW AIR MOVES IN.
SKIES SHOULD BECOME MOSTLY SUNNY ACROSS CENTRAL AND SOUTHERN
PENN...WHILE PERIODS OF BKN-OVC STRATO CU WILL LIKELY FORM ACROSS
THE NRN MTNS OF PENN WITH EVEN A FEW SPRINKLES POSSIBLE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A RELATIVELY QUIET STRETCH OF WEATHER IS IN STORE THROUGH THIS
WEEKEND AND MUCH OF NEXT WEEK. PWATS WILL DROP TO -1SD FRI AND
REMAIN THAT WAY THRU THE WEEKEND...WHICH WILL BE A NICE CHANGE FROM
THE MUGGY AIRMASS WE SAW MUCH OF THE PAST WEEK.
IN ALL...THE WEEKEND LOOKS PLEASANT WITH LOW HUMIDITY AND
TEMPERATURES RUNNING A FEW DEGREES BELOW LATE-AUGUST NORMALS. THE
ONLY POTENTIAL FLY IN THE OINTMENT IS A WEAK AREA OF LOW PRESSURE
OFF THE MID-ATLANTIC COAST THAT COULD TRY TO PUSH A BIT OF
CLOUDINESS WESTWARD INTO EASTERN PA ON SUNDAY.
A WEAKENING COLD FRONT WILL CROSS THE COMMONWEALTH ON
MONDAY...ACCOMPANIED BY AN OUTSIDE CHC FOR A FEW SHRA/TSRA.
BEHIND THE FRONT...THE MIDDLE OF NEXT WEEK SHOULD SEE A RETURN TO
LOW HUMIDITY AND SLIGHTLY BELOW NORMAL TEMPS.
&&
.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
GIVEN THE COPIOUS AMOUNTS OF WIDESPREAD PRECIPITATION THIS
AFTERNOON AND EVENING AND THE CLEARING SKIES AND WEAK FLOW EXPECT
FOR LOW STRATOCU AND PATCHY DENSE FOG TO DEVELOP OVERNIGHT. IN THE
11U-3.9U THERE IS A LINE OF DRY AIR MOVING IN WHICH WILL LIMIT AND
PREVENT FOG/LOW STRATOCU DEVELOPMENT. IPT HAS DECOUPLED WITH LIFR
CIGS AND VSBYS. GIVEN THE WESTERLY FLOW EXPECT WESTERN AND CENTRAL
TAF SITES TO HAVE PERIODS OF IFR FROM 06Z TO 13Z WITH MVFR TO
POSSIBLY VFR IN THE INTERIM. AS THE REGION MIXES OUT AFTER
SUNRISE AND DRY AIR MIXES DOWN ANY AREAS OF 1/2SM VSBY FOG WILL
TEND TO MVFR BETWEEN 12Z TO 15Z BEFORE BECOMING VFR ACROSS ALL OF
CENTRAL AND SOUTHERN PENN.
OUTLOOK...
SAT-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...LAMBERT/STEINBUGL
LONG TERM...EVANEGO
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
516 PM EDT FRI AUG 21 2015
.SYNOPSIS...
H PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTH...THOUGH MUCH
DRYING IN THE WAKE OF THE FRONTAL PASSAGE IS UNLIKELY. ANOTHER COLD
FRONT WILL CROSS THE REGION ON MONDAY...WITH A MUCH DRIER PERIOD
STARTING ON TUESDAY. ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
WILL RETURN BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 510PM FRIDAY...AREA IS CURRENTLY CLEAR OF ALL BUT THE LIGHTEST
ISOLATED SHOWERS. LATEST HRRR ALSO HAS NO NEW CONVECTION IN THE
NEAR FUTURE. CONVECTION THAT EARLIER CAMS HAD BY 18Z HAS NOT
MATERIALIZED. HAVE THUS LOWERED THE PRECIP. FORECAST FOR THE NEXT 6
HOURS.
AS OF 200 PM...HIGH PRESSURE CONTINUES TO RIDGE DOWN THE EAST
COAST IN A WEDGE-LIKE CONFIGURATION. SFC FRONT NOW STRETCHES FROM
MIDDLE GA THRU THE SC MIDLANDS...WITH NE WINDS AND RELATIVELY DRY
DEWPTS ACRS MOST OF THE AREA. PATCHY MIDLEVEL CLOUDS REMAIN ACRS
MUCH OF THE CWFA RESULTING FROM A WEAK VORT MAX DRIFTING ACRS THE
AREA. THIS DECK APPEARS THINNER THAN IT DID LATE THIS MRNG...AND AS
THE VORT MAX CONTINUES TO MOVE EAST IT SHOULD FOLLOW. A SHALLOW CU
FIELD HAS QUICKLY BROKEN OUT AS SUNSHINE RETURNS...PARTICULARLY
OVER THE MTNS OF SW NC AND NE GA...AND NOW THE UPPER SAVANNAH
RIVER VALLEY. A COUPLE SHOWERS ARE ALSO SEEN ON RADAR TO OUR
WEST. SHORT RANGE CAM GUIDANCE HAS GENERALLY OVERDONE THE STATE
OF CONVECTION THIS MORNING POSSIBLY BECAUSE THEY UNDERESTIMATED
THE RESTRICTED WARMING ASSOC WITH THE CLOUD COVER. THE HRRR HAS
TRENDED TOWARD MORE ISOLATED COVERAGE. SEEING THE RATHER WEAK
ACTIVITY UPSTREAM SUPPORTS MAINLY ISOLD RANGE POPS THIS AFTN. A
SECOND VORT MAX OVER NRN ALABAMA WILL ARRIVE THIS EVENING...AND
ENOUGH ELEVATED INSTABILITY AND LOW LEVEL MOISTURE WILL STILL BE
PRESENT FOR ISOLATED CONVECTION TO OCCUR TONIGHT OVER MUCH OF THE
AREA. DESPITE HIGH PRESSURE ALREADY HAVING BEGUN TO SETTLE INTO THE
AREA AS OF THIS AFTERNOON...APPRECIABLE DRYING DOES NOT OCCUR UNTIL
TOMORROW. ANY CONVECTIVE SHOWERS THAT OCCUR THIS AFTN OR TONIGHT ARE
LIKELY TO PRODUCE HIGH RAINFALL RATES. MIN TEMPS WILL BE SLIGHTLY
ABOVE CLIMO TONIGHT WITH A FAIR AMOUNT OF CLOUD COVER...GIVEN THE
UPPER DISTURBANCE AND MOIST FLOW INTO THE BLUE RIDGE.
SUBSIDENCE CAPPING IS EXPECTED TO KEEP CONVECTION ISOLATED OR
TOTALLY AT BAY OVER MUCH OF THE NC PIEDMONT ON SATURDAY...AND
SCATTERED AT BEST AROUND THE FRINGES OF THE AIRMASS /IN THE MTNS
AND SAVANNAH VALLEY/. THE ARRIVAL OF DRIER AIR ALOFT IMPLIES
GUSTY/STRONG WINDS MAY BE OF A BIT MORE CONCERN...AND HEAVY RAIN
A BIT LESS. MAX TEMPS AGAIN WILL BE SLIGHTLY BELOW NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM EDT FRIDAY...THE SHORT TERM FCST PERIOD INITIALIZES
SATURDAY EVENING WITH THE UPPER PATTERN HIGHLIGHTED BY AN EASTERN
GULF ANTICYCLONE...WHILE A SHORTWAVE TROF SLIDES THROUGH THE
MIDSOUTH...WITH A DEEPER LONGWAVE TROF ADVECTING OVER THE UPPER
MIDWEST. AT THE SFC...RELATIVELY DRIER NORTHERLY FLOW WILL PREVAIL
OVER THE WESTERN CAROLINAS AND NORTHEAST GEORGIA CONSEQUENT OF
ELONGATED HIGH PRESSURE MOVING EAST OF THE SOUTHERN/CENTRAL APPS.
MODELS HINT AT ISOLATED/SCATTERED CONVECTION POSSIBLE AT FCST
INITIALIZATION ACROSS THE AREA...HOWEVER MAINLY FOCUSED OVER
THE NC/GA HIGH TERRAIN AND THE UPPER SAVANNAH RIVER VALLEY.
EXPECTING THE UPPER SHORT WAVE TO ADVECT FURTHER EAST THROUGH
THE NIGHT WARRANTING MENTIONABLE POPS THROUGH MORNING OVER THE
WEST...SPREADING EAST AND INCREASING INTO THE AFTERNOON. THUS THE
FCST FEATURES CHANCE POPS DURING THE DAY ON SUNDAY.
MEANWHILE...A COLD FRONT WILL BE MOVING THROUGH THE MID MISSISSIPPI
RIVER VALLEY INTO THE OHIO VALLEY BY EARLY MONDAY MORNING...ENTERING
THE NC HIGH TERRAIN LATE AFTERNOON TO EARLY EVENING MONDAY.
STILL SOME UNCERTAINTY AS TO HOW UNSTABLE THE AIRMASS WILL BE OUT
AHEAD OF THE FRONT HOWEVER WITH THE LATEST THE NAM COMING IN MORE SO
THAN PREVIOUS RUNS. THUS...WOULDNT BE SURPRISED TO SEE CONVECTION
IN THE WARM SECTOR MONDAY AFTERNOON AHEAD/ALONG THE FRONT.
FORTUNATELY...THE MOST ENHANCED UPPER WIND FIELD WILL BE WELL TO
THE NORTH ALONG WITH THE PRIMARY UPPER LOW. THEREFORE SOUNDINGS
FAVOR MORE OF A HAIL AND HYDRO THREAT AT THIS TIME...WITH EVEN THAT
BEING ISOLATED. POPS ON MONDAY WILL FEATURE CHANCE LEVELS OVER THE
HIGH TERRAIN TAPERING TO SLIGHT CHANCE LEVELS EAST ALONG THE I77
CORRIDOR. AS FOR HURRICANE DANNY...LATEST ADVISORY ISSUANCE FROM
NHC INDICATES SOME WEAKENING THIS WEEKEND AS IT ENCOUNTERS DRIER
AIR WITH THE CENTER OF CIRCULATION JUST OFF THE EAST COAST OF PUERTO
RICO BY MONDAY AFTERNOON...LIKELY IN THE FORM OF A TROPICAL STORM.
TEMPERATURES THROUGH THE PERIOD WILL SLOWLY MODERATE...WITH NEAR
NORMAL HIGHS FCST ON SUNDAY AND HIGHS JUST ABOVE NORMAL ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
OF 200 PM FRIDAY...OVERALL MODEL AGREEMENT FOR THE MEDIUM RANGE
IS ABOVE AVERAGE. THE UPPER PATTERN WILL CONTINUE TO AMPLIFY...WITH
A SUBSTANTIAL RIDGE STILL IN PLACE OVER THE WESTERN CONUS AND A
RAPIDLY DEEPENING TROUGH OVER THE EAST. AT THE SURFACE...THE
APPROACHING FRONTAL BOUNDARY WILL MOVE THROUGH THE CWFA AT THE
BEGINNING OF THE PERIOD. DESPITE THE FRONTAL PASSAGE COINCIDING WITH
PEAK HEATING...DEEP NORTHWESTERLY FLOW WILL DRIVE SOME LEVEL OF
DRYING BEFORE THE BOUNDARY ARRIVES. MODERATE INSTABILITY IS POSSIBLE
IN THE HIGHER TERRAIN...BUT IS UNIMPRESSIVE ELSEWHERE. THOUGH THERE
IS SOME QPF RESPONSE AS THE FRONT PASSES...A LACK OF DEEP MOISTURE
AND LESS THAN THRILLING SHEAR PROFILES SHOULD KEEP CHANCES OF
CONVECTION TO NO MORE THAN CHANCE OUTSIDE THE MOUNTAINS...AND
HIGH-END CHANCE IN THE HIGHER TERRAIN.
AN UNUSUALLY QUIET PERIOD...ESPECIALLY FOR THE END OF SUMMER...WILL
ARRIVE AFTER THE FRONT CROSSES THE CWA. A SURFACE HIGH WILL BUILD IN
FROM THE OHIO RIVER VALLEY...AND PWATS DROP TO WELL BELOW NORMAL. A
NORTHERLY COMPONENT IS MAINTAINED IN THE SURFACE WINDS FOR ALMOST
THE ENTIRE MEDIUM RANGE...SO KEEP A "SILENT 10" POP IN EACH
AFTERNOON FOR THE MAJORITY OF THE AREA. SLIGHT CHANCE POPS WERE USED
BORDERING COLUMBIA`S AREA...WITH ANY CHANCE AT CONVECTION FOLLOWING
THE BETTER INSTABILITY. THE UPPER PATTERN WILL FLATTEN OUT BY THE
END OF NEXT WEEK...AND THE INFLUENCE OF ATLANTIC HIGH PRESSURE WILL
BUILD BACK IN. THIS INFLUENCE WILL BE REFLECTED IN A SLIGHT
MOISTENING DUE TO AN INCREASED SOUTHERLY FLOW AT THE SURFACE. MAX
AND MIN TEMPS WILL BE NEAR CLIMO THROUGH THE PERIOD.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...VFR. A PASSING UPPER DISTURBANCE THIS AFTERNOON
WILL MAINTAIN A FAIR AMOUNT OF HIGH CLOUD COVER AND LIMIT
DESTABILIZATION...SO EVEN THOUGH LOW VFR CU WILL DEVELOP THEY
ARE UNLIKELY TO BECOME DEEP ENOUGH FOR ANY PRECIP TO RESULT. HIGH
PRESSURE WILL CONTINUE TO BUILD DOWN THE EAST COAST REINFORCING
NELY WINDS...THOUGH THEY ARE EXPECTED TO VEER SLIGHTLY SOUTH OF
EAST FOR A TIME THIS EVENING. A SECOND DISTURBANCE ARRIVING TONIGHT
WILL BRING ADDITIONAL CLOUD COVER AND A BETTER CHANCE FOR LIGHT
SHOWERS...BOTH OF WHICH ARE EXPECTED TO CAUSE LITTLE IMPACT. WINDS
WILL RETURN TO NE AFTER DAYBREAK.
ELSEWHERE...IN THE WAKE OF ONE UPPER DISTURBANCE...HIGHER CLOUDS
SHOULD MOVE EAST AND RETURNING SUNSHINE WILL ALLOW CUMULUS TO
BUILD IN THEIR WAKE. ISOLD TO WIDELY SCATTERED SHRA AND PERHAPS
A TSRA OR TWO HAS PROMPTED A VCSH MENTION AT KGSP/KGMU. A SECOND
DISTURBANCE ARRIVING TONIGHT WILL BRING BETTER CHANCES TO MOST OF
THE AREA...BUT STILL ONLY VCSH WORTHY AT BEST. SOME FOG IS EXPECTED
IN MTN VALLEYS AND IN THE SAVANNAH RIVER VALLEY...TAKING KAVL/KAND
DOWN TO MVFR IN THE EARLY MRNG. POPS DIMINISH AFTER DAYBREAK AS
THE DISTURBANCE DEPARTS...BEFORE RAMPING UP AGAIN TOWARD MIDDAY
WITH DIURNAL DESTABILIZATION. WINDS WILL REFLECT THE HIGH PRESSURE
RIDGING DOWN THE EAST SIDE OF THE APPALACHIANS IN A REGIME SIMILAR
TO A CAD WEDGE...MAINLY NE OVER THE PIEDMONT AND SE AT KAVL.
OUTLOOK...DRY HIGH PRESSURE WILL MAINTAIN LOW POTENTIAL FOR MORNING
RESTRICTIONS THROUGH THE WEEKEND. A RETURN TO A TYPICAL DIURNAL
CYCLE OF CONVECTION MAY OCCUR EARLY NEXT WEEK AS A COLD FRONT
ARRIVES FROM THE NORTHWEST.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 87%
KAVL HIGH 96% HIGH 100% HIGH 90% HIGH 82%
KHKY HIGH 100% HIGH 100% LOW 55% MED 72%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 95%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...WIMBERLEY/WJM
SHORT TERM...CDG
LONG TERM...LEV
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
237 PM EDT FRI AUG 21 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTH...THOUGH
MUCH DRYING IN THE WAKE OF THE FRONTAL PASSAGE IS UNLIKELY.
ANOTHER COLD FRONT WILL CROSS THE REGION ON MONDAY...WITH A MUCH
DRIER PERIOD STARTING ON TUESDAY. ISOLATED AFTERNOON SHOWERS AND
THUNDERSTORMS WILL RETURN BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 230 PM...HIGH PRESSURE CONTINUES TO RIDGE DOWN THE EAST
COAST IN A WEDGE-LIKE CONFIGURATION. SFC FRONT NOW STRETCHES FROM
MIDDLE GA THRU THE SC MIDLANDS...WITH NE WINDS AND RELATIVELY DRY
DEWPTS ACRS MOST OF THE AREA. PATCHY MIDLEVEL CLOUDS REMAIN ACRS
MUCH OF THE CWFA RESULTING FROM A WEAK VORT MAX DRIFTING ACRS THE
AREA. THIS DECK APPEARS THINNER THAN IT DID LATE THIS MRNG...AND AS
THE VORT MAX CONTINUES TO MOVE EAST IT SHOULD FOLLOW. A SHALLOW CU
FIELD HAS QUICKLY BROKEN OUT AS SUNSHINE RETURNS...PARTICULARLY
OVER THE MTNS OF SW NC AND NE GA...AND NOW THE UPPER SAVANNAH
RIVER VALLEY. A COUPLE SHOWERS ARE ALSO SEEN ON RADAR TO OUR
WEST. SHORT RANGE CAM GUIDANCE HAS GENERALLY OVERDONE THE STATE
OF CONVECTION THIS MORNING POSSIBLY BECAUSE THEY UNDERESTIMATED
THE RESTRICTED WARMING ASSOC WITH THE CLOUD COVER. THE HRRR HAS
TRENDED TOWARD MORE ISOLATED COVERAGE. SEEING THE RATHER WEAK
ACTIVITY UPSTREAM SUPPORTS MAINLY ISOLD RANGE POPS THIS AFTN. A
SECOND VORT MAX OVER NRN ALABAMA WILL ARRIVE THIS EVENING...AND
ENOUGH ELEVATED INSTABILITY AND LOW LEVEL MOISTURE WILL STILL BE
PRESENT FOR ISOLATED CONVECTION TO OCCUR TONIGHT OVER MUCH OF THE
AREA. DESPITE HIGH PRESSURE ALREADY HAVING BEGUN TO SETTLE INTO THE
AREA AS OF THIS AFTERNOON...APPRECIABLE DRYING DOES NOT OCCUR UNTIL
TOMORROW. ANY CONVECTIVE SHOWERS THAT OCCUR THIS AFTN OR TONIGHT ARE
LIKELY TO PRODUCE HIGH RAINFALL RATES. MIN TEMPS WILL BE SLIGHTLY
ABOVE CLIMO TONIGHT WITH A FAIR AMOUNT OF CLOUD COVER...GIVEN THE
UPPER DISTURBANCE AND MOIST FLOW INTO THE BLUE RIDGE.
SUBSIDENCE CAPPING IS EXPECTED TO KEEP CONVECTION ISOLATED OR
TOTALLY AT BAY OVER MUCH OF THE NC PIEDMONT ON SATURDAY...AND
SCATTERED AT BEST AROUND THE FRINGES OF THE AIRMASS /IN THE MTNS
AND SAVANNAH VALLEY/. THE ARRIVAL OF DRIER AIR ALOFT IMPLIES
GUSTY/STRONG WINDS MAY BE OF A BIT MORE CONCERN...AND HEAVY RAIN
A BIT LESS. MAX TEMPS AGAIN WILL BE SLIGHTLY BELOW NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM EDT FRIDAY...THE SHORT TERM FCST PERIOD INITIALIZES
SATURDAY EVENING WITH THE UPPER PATTERN HIGHLIGHTED BY AN EASTERN
GULF ANTICYCLONE...WHILE A SHORTWAVE TROF SLIDES THROUGH THE
MIDSOUTH...WITH A DEEPER LONGWAVE TROF ADVECTING OVER THE UPPER
MIDWEST. AT THE SFC...RELATIVELY DRIER NORTHERLY FLOW WILL PREVAIL
OVER THE WESTERN CAROLINAS AND NORTHEAST GEORGIA CONSEQUENT OF
ELONGATED HIGH PRESSURE MOVING EAST OF THE SOUTHERN/CENTRAL APPS.
MODELS HINT AT ISOLATED/SCATTERED CONVECTION POSSIBLE AT FCST
INITIALIZATION ACROSS THE AREA...HOWEVER MAINLY FOCUSED OVER
THE NC/GA HIGH TERRAIN AND THE UPPER SAVANNAH RIVER VALLEY.
EXPECTING THE UPPER SHORT WAVE TO ADVECT FURTHER EAST THROUGH
THE NIGHT WARRANTING MENTIONABLE POPS THROUGH MORNING OVER THE
WEST...SPREADING EAST AND INCREASING INTO THE AFTERNOON. THUS THE
FCST FEATURES CHANCE POPS DURING THE DAY ON SUNDAY.
MEANWHILE...A COLD FRONT WILL BE MOVING THROUGH THE MID MISSISSIPPI
RIVER VALLEY INTO THE OHIO VALLEY BY EARLY MONDAY MORNING...ENTERING
THE NC HIGH TERRAIN LATE AFTERNOON TO EARLY EVENING MONDAY.
STILL SOME UNCERTAINTY AS TO HOW UNSTABLE THE AIRMASS WILL BE OUT
AHEAD OF THE FRONT HOWEVER WITH THE LATEST THE NAM COMING IN MORE SO
THAN PREVIOUS RUNS. THUS...WOULDNT BE SURPRISED TO SEE CONVECTION
IN THE WARM SECTOR MONDAY AFTERNOON AHEAD/ALONG THE FRONT.
FORTUNATELY...THE MOST ENHANCED UPPER WIND FIELD WILL BE WELL TO
THE NORTH ALONG WITH THE PRIMARY UPPER LOW. THEREFORE SOUNDINGS
FAVOR MORE OF A HAIL AND HYDRO THREAT AT THIS TIME...WITH EVEN THAT
BEING ISOLATED. POPS ON MONDAY WILL FEATURE CHANCE LEVELS OVER THE
HIGH TERRAIN TAPERING TO SLIGHT CHANCE LEVELS EAST ALONG THE I77
CORRIDOR. AS FOR HURRICANE DANNY...LATEST ADVISORY ISSUANCE FROM
NHC INDICATES SOME WEAKENING THIS WEEKEND AS IT ENCOUNTERS DRIER
AIR WITH THE CENTER OF CIRCULATION JUST OFF THE EAST COAST OF PUERTO
RICO BY MONDAY AFTERNOON...LIKELY IN THE FORM OF A TROPICAL STORM.
TEMPERATURES THROUGH THE PERIOD WILL SLOWLY MODERATE...WITH NEAR
NORMAL HIGHS FCST ON SUNDAY AND HIGHS JUST ABOVE NORMAL ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM FRIDAY...OVERALL MODEL AGREEMENT FOR THE MEDIUM
RANGE IS ABOVE AVERAGE. THE UPPER PATTERN WILL CONTINUE TO
AMPLIFY...WITH A SUBSTANTIAL RIDGE STILL IN PLACE OVER THE WESTERN
CONUS AND A RAPIDLY DEEPENING TROUGH OVER THE EAST. AT THE
SURFACE...THE APPROACHING FRONTAL BOUNDARY WILL MOVE THROUGH THE
CWFA AT THE BEGINNING OF THE PERIOD. DESPITE THE FRONTAL PASSAGE
COINCIDING WITH PEAK HEATING...DEEP NORTHWESTERLY FLOW WILL DRIVE
SOME LEVEL OF DRYING BEFORE THE BOUNDARY ARRIVES. MODERATE
INSTABILITY IS POSSIBLE IN THE HIGHER TERRAIN...BUT IS
UNIMPRESSIVE ELSEWHERE. THOUGH THERE IS SOME QPF RESPONSE AS THE
FRONT PASSES...A LACK OF DEEP MOISTURE AND LESS THAN THRILLING
SHEAR PROFILES SHOULD KEEP CHANCES OF CONVECTION TO NO MORE THAN
CHANCE OUTSIDE THE MOUNTAINS...AND HIGH-END CHANCE IN THE HIGHER
TERRAIN.
AN UNUSUALLY QUIET PERIOD...ESPECIALLY FOR THE END OF SUMMER...WILL
ARRIVE AFTER THE FRONT CROSSES THE CWA. A SURFACE HIGH WILL BUILD IN
FROM THE OHIO RIVER VALLEY...AND PWATS DROP TO WELL BELOW NORMAL. A
NORTHERLY COMPONENT IS MAINTAINED IN THE SURFACE WINDS FOR ALMOST
THE ENTIRE MEDIUM RANGE...SO KEEP A "SILENT 10" POP IN EACH
AFTERNOON FOR THE MAJORITY OF THE AREA. SLIGHT CHANCE POPS WERE USED
BORDERING COLUMBIA`S AREA...WITH ANY CHANCE AT CONVECTION FOLLOWING
THE BETTER INSTABILITY. THE UPPER PATTERN WILL FLATTEN OUT BY THE
END OF NEXT WEEK...AND THE INFLUENCE OF ATLANTIC HIGH PRESSURE WILL
BUILD BACK IN. THIS INFLUENCE WILL BE REFLECTED IN A SLIGHT
MOISTENING DUE TO AN INCREASED SOUTHERLY FLOW AT THE SURFACE. MAX
AND MIN TEMPS WILL BE NEAR CLIMO THROUGH THE PERIOD.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...VFR. A PASSING UPPER DISTURBANCE THIS AFTERNOON
WILL MAINTAIN A FAIR AMOUNT OF HIGH CLOUD COVER AND LIMIT
DESTABILIZATION...SO EVEN THOUGH LOW VFR CU WILL DEVELOP THEY
ARE UNLIKELY TO BECOME DEEP ENOUGH FOR ANY PRECIP TO RESULT. HIGH
PRESSURE WILL CONTINUE TO BUILD DOWN THE EAST COAST REINFORCING
NELY WINDS...THOUGH THEY ARE EXPECTED TO VEER SLIGHTLY SOUTH OF
EAST FOR A TIME THIS EVENING. A SECOND DISTURBANCE ARRIVING TONIGHT
WILL BRING ADDITIONAL CLOUD COVER AND A BETTER CHANCE FOR LIGHT
SHOWERS...BOTH OF WHICH ARE EXPECTED TO CAUSE LITTLE IMPACT. WINDS
WILL RETURN TO NE AFTER DAYBREAK.
ELSEWHERE...IN THE WAKE OF ONE UPPER DISTURBANCE...HIGHER CLOUDS
SHOULD MOVE EAST AND RETURNING SUNSHINE WILL ALLOW CUMULUS TO
BUILD IN THEIR WAKE. ISOLD TO WIDELY SCATTERED SHRA AND PERHAPS
A TSRA OR TWO HAS PROMPTED A VCSH MENTION AT KGSP/KGMU. A SECOND
DISTURBANCE ARRIVING TONIGHT WILL BRING BETTER CHANCES TO MOST OF
THE AREA...BUT STILL ONLY VCSH WORTHY AT BEST. SOME FOG IS EXPECTED
IN MTN VALLEYS AND IN THE SAVANNAH RIVER VALLEY...TAKING KAVL/KAND
DOWN TO MVFR IN THE EARLY MRNG. POPS DIMINISH AFTER DAYBREAK AS
THE DISTURBANCE DEPARTS...BEFORE RAMPING UP AGAIN TOWARD MIDDAY
WITH DIURNAL DESTABILIZATION. WINDS WILL REFLECT THE HIGH PRESSURE
RIDGING DOWN THE EAST SIDE OF THE APPALACHIANS IN A REGIME SIMILAR
TO A CAD WEDGE...MAINLY NE OVER THE PIEDMONT AND SE AT KAVL.
OUTLOOK...DRY HIGH PRESSURE WILL MAINTAIN LOW POTENTIAL FOR MORNING
RESTRICTIONS THROUGH THE WEEKEND. A RETURN TO A TYPICAL DIURNAL
CYCLE OF CONVECTION MAY OCCUR EARLY NEXT WEEK AS A COLD FRONT
ARRIVES FROM THE NORTHWEST.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 91%
KAVL HIGH 99% HIGH 100% HIGH 80% HIGH 86%
KHKY HIGH 100% HIGH 100% HIGH 82% MED 70%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 94%
KAND HIGH 100% HIGH 100% HIGH 97% HIGH 97%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...WIMBERLEY
SHORT TERM...CDG
LONG TERM...LEV
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
212 PM EDT FRI AUG 21 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTH...THOUGH
MUCH DRYING IN THE WAKE OF THE FRONTAL PASSAGE IS UNLIKELY.
ANOTHER COLD FRONT WILL CROSS THE REGION ON MONDAY...WITH A MUCH
DRIER PERIOD STARTING ON TUESDAY. ISOLATED AFTERNOON SHOWERS AND
THUNDERSTORMS WILL RETURN BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 200 PM...PATCHY MIDLEVEL CLOUDS REMAIN ACRS MUCH OF THE
CWFA RESULTING FROM A WEAK VORT MAX DRIFTING ACRS THE AREA. THIS
DECK APPEARS THINNER THAN IT DID LATE THIS MRNG...AND AS THE VORT
MAX CONTINUES TO MOVE EAST IT SHOULD FOLLOW. A SHALLOW CU FIELD
HAS QUICKLY BROKEN OUT AS SUNSHINE RETURNS...PARTICULARLY OVER
THE MTNS OF SW NC AND NE GA...AND NOW THE UPPER SAVANNAH RIVER
VALLEY. A COUPLE SHOWERS ARE ALSO SEEN ON RADAR TO OUR WEST. SHORT
RANGE CAM GUIDANCE HAS GENERALLY OVERDONE THE STATE OF CONVECTION
THIS MORNING POSSIBLY BECAUSE THEY UNDERESTIMATED THE RESTRICTED
WARMING ASSOC WITH THE CLOUD COVER. THE HRRR HAS TRENDED TOWARD
MORE ISOLATED COVERAGE. SEEING THE RATHER WEAK ACTIVITY UPSTREAM
SUPPORTS MAINLY ISOLD RANGE POPS THIS AFTN. A SECOND VORT MAX
OVER NRN ALABAMA WILL ARRIVE THIS EVENING...AND ENOUGH ELEVATED
INSTABILITY AND LOW LEVEL MOISTURE WILL STILL BE PRESENT FOR
ISOLATED CONVECTION TO OCCUR TONIGHT OVER MUCH OF THE AREA.
MORE DETAILS TO COME IN DISCUSSION WITH AFTN PACKAGE DURING THE
NEXT HOUR.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM EDT FRIDAY...THE SHORT TERM FCST PERIOD INITIALIZES
SATURDAY EVENING WITH THE UPPER PATTERN HIGHLIGHTED BY AN EASTERN
GULF ANTICYCLONE...WHILE A SHORTWAVE TROF SLIDES THROUGH THE
MIDSOUTH...WITH A DEEPER LONGWAVE TROF ADVECTING OVER THE UPPER
MIDWEST. AT THE SFC...RELATIVELY DRIER NORTHERLY FLOW WILL PREVAIL
OVER THE WESTERN CAROLINAS AND NORTHEAST GEORGIA CONSEQUENT OF
ELONGATED HIGH PRESSURE MOVING EAST OF THE SOUTHERN/CENTRAL APPS.
MODELS HINT AT ISOLATED/SCATTERED CONVECTION POSSIBLE AT FCST
INITIALIZATION ACROSS THE AREA...HOWEVER MAINLY FOCUSED OVER
THE NC/GA HIGH TERRAIN AND THE UPPER SAVANNAH RIVER VALLEY.
EXPECTING THE UPPER SHORT WAVE TO ADVECT FURTHER EAST THROUGH
THE NIGHT WARRANTING MENTIONABLE POPS THROUGH MORNING OVER THE
WEST...SPREADING EAST AND INCREASING INTO THE AFTERNOON. THUS THE
FCST FEATURES CHANCE POPS DURING THE DAY ON SUNDAY.
MEANWHILE...A COLD FRONT WILL BE MOVING THROUGH THE MID MISSISSIPPI
RIVER VALLEY INTO THE OHIO VALLEY BY EARLY MONDAY MORNING...ENTERING
THE NC HIGH TERRAIN LATE AFTERNOON TO EARLY EVENING MONDAY.
STILL SOME UNCERTAINTY AS TO HOW UNSTABLE THE AIRMASS WILL BE OUT
AHEAD OF THE FRONT HOWEVER WITH THE LATEST THE NAM COMING IN MORE SO
THAN PREVIOUS RUNS. THUS...WOULDNT BE SURPRISED TO SEE CONVECTION
IN THE WARM SECTOR MONDAY AFTERNOON AHEAD/ALONG THE FRONT.
FORTUNATELY...THE MOST ENHANCED UPPER WIND FIELD WILL BE WELL TO
THE NORTH ALONG WITH THE PRIMARY UPPER LOW. THEREFORE SOUNDINGS
FAVOR MORE OF A HAIL AND HYDRO THREAT AT THIS TIME...WITH EVEN THAT
BEING ISOLATED. POPS ON MONDAY WILL FEATURE CHANCE LEVELS OVER THE
HIGH TERRAIN TAPERING TO SLIGHT CHANCE LEVELS EAST ALONG THE I77
CORRIDOR. AS FOR HURRICANE DANNY...LATEST ADVISORY ISSUANCE FROM
NHC INDICATES SOME WEAKENING THIS WEEKEND AS IT ENCOUNTERS DRIER
AIR WITH THE CENTER OF CIRCULATION JUST OFF THE EAST COAST OF PUERTO
RICO BY MONDAY AFTERNOON...LIKELY IN THE FORM OF A TROPICAL STORM.
TEMPERATURES THROUGH THE PERIOD WILL SLOWLY MODERATE...WITH NEAR
NORMAL HIGHS FCST ON SUNDAY AND HIGHS JUST ABOVE NORMAL ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM FRIDAY...OVERALL MODEL AGREEMENT FOR THE MEDIUM
RANGE IS ABOVE AVERAGE. THE UPPER PATTERN WILL CONTINUE TO
AMPLIFY...WITH A SUBSTANTIAL RIDGE STILL IN PLACE OVER THE WESTERN
CONUS AND A RAPIDLY DEEPENING TROUGH OVER THE EAST. AT THE
SURFACE...THE APPROACHING FRONTAL BOUNDARY WILL MOVE THROUGH THE
CWFA AT THE BEGINNING OF THE PERIOD. DESPITE THE FRONTAL PASSAGE
COINCIDING WITH PEAK HEATING...DEEP NORTHWESTERLY FLOW WILL DRIVE
SOME LEVEL OF DRYING BEFORE THE BOUNDARY ARRIVES. MODERATE
INSTABILITY IS POSSIBLE IN THE HIGHER TERRAIN...BUT IS
UNIMPRESSIVE ELSEWHERE. THOUGH THERE IS SOME QPF RESPONSE AS THE
FRONT PASSES...A LACK OF DEEP MOISTURE AND LESS THAN THRILLING
SHEAR PROFILES SHOULD KEEP CHANCES OF CONVECTION TO NO MORE THAN
CHANCE OUTSIDE THE MOUNTAINS...AND HIGH-END CHANCE IN THE HIGHER
TERRAIN.
AN UNUSUALLY QUIET PERIOD...ESPECIALLY FOR THE END OF SUMMER...WILL
ARRIVE AFTER THE FRONT CROSSES THE CWA. A SURFACE HIGH WILL BUILD IN
FROM THE OHIO RIVER VALLEY...AND PWATS DROP TO WELL BELOW NORMAL. A
NORTHERLY COMPONENT IS MAINTAINED IN THE SURFACE WINDS FOR ALMOST
THE ENTIRE MEDIUM RANGE...SO KEEP A "SILENT 10" POP IN EACH
AFTERNOON FOR THE MAJORITY OF THE AREA. SLIGHT CHANCE POPS WERE USED
BORDERING COLUMBIA`S AREA...WITH ANY CHANCE AT CONVECTION FOLLOWING
THE BETTER INSTABILITY. THE UPPER PATTERN WILL FLATTEN OUT BY THE
END OF NEXT WEEK...AND THE INFLUENCE OF ATLANTIC HIGH PRESSURE WILL
BUILD BACK IN. THIS INFLUENCE WILL BE REFLECTED IN A SLIGHT
MOISTENING DUE TO AN INCREASED SOUTHERLY FLOW AT THE SURFACE. MAX
AND MIN TEMPS WILL BE NEAR CLIMO THROUGH THE PERIOD.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...VFR. A PASSING UPPER DISTURBANCE THIS AFTERNOON
WILL MAINTAIN A FAIR AMOUNT OF HIGH CLOUD COVER AND LIMIT
DESTABILIZATION...SO EVEN THOUGH LOW VFR CU WILL DEVELOP THEY
ARE UNLIKELY TO BECOME DEEP ENOUGH FOR ANY PRECIP TO RESULT. HIGH
PRESSURE WILL CONTINUE TO BUILD DOWN THE EAST COAST REINFORCING
NELY WINDS...THOUGH THEY ARE EXPECTED TO VEER SLIGHTLY SOUTH OF
EAST FOR A TIME THIS EVENING. A SECOND DISTURBANCE ARRIVING TONIGHT
WILL BRING ADDITIONAL CLOUD COVER AND A BETTER CHANCE FOR LIGHT
SHOWERS...BOTH OF WHICH ARE EXPECTED TO CAUSE LITTLE IMPACT. WINDS
WILL RETURN TO NE AFTER DAYBREAK.
ELSEWHERE...IN THE WAKE OF ONE UPPER DISTURBANCE...HIGHER CLOUDS
SHOULD MOVE EAST AND RETURNING SUNSHINE WILL ALLOW CUMULUS TO
BUILD IN THEIR WAKE. ISOLD TO WIDELY SCATTERED SHRA AND PERHAPS
A TSRA OR TWO HAS PROMPTED A VCSH MENTION AT KGSP/KGMU. A SECOND
DISTURBANCE ARRIVING TONIGHT WILL BRING BETTER CHANCES TO MOST OF
THE AREA...BUT STILL ONLY VCSH WORTHY AT BEST. SOME FOG IS EXPECTED
IN MTN VALLEYS AND IN THE SAVANNAH RIVER VALLEY...TAKING KAVL/KAND
DOWN TO MVFR IN THE EARLY MRNG. POPS DIMINISH AFTER DAYBREAK AS
THE DISTURBANCE DEPARTS...BEFORE RAMPING UP AGAIN TOWARD MIDDAY
WITH DIURNAL DESTABILIZATION. WINDS WILL REFLECT THE HIGH PRESSURE
RIDGING DOWN THE EAST SIDE OF THE APPALACHIANS IN A REGIME SIMILAR
TO A CAD WEDGE...MAINLY NE OVER THE PIEDMONT AND SE AT KAVL.
OUTLOOK...DRY HIGH PRESSURE WILL MAINTAIN LOW POTENTIAL FOR MORNING
RESTRICTIONS THROUGH THE WEEKEND. A RETURN TO A TYPICAL DIURNAL
CYCLE OF CONVECTION MAY OCCUR EARLY NEXT WEEK AS A COLD FRONT
ARRIVES FROM THE NORTHWEST.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 91%
KAVL HIGH 99% HIGH 100% HIGH 80% HIGH 86%
KHKY HIGH 100% HIGH 100% HIGH 82% MED 70%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 94%
KAND HIGH 100% HIGH 100% HIGH 97% HIGH 97%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...WIMBERLEY
SHORT TERM...CDG
LONG TERM...LEV
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
1114 AM EDT FRI AUG 21 2015
.DISCUSSION...
POST-FRONTAL HIGH PRESSURE FILLING INTO THE REGION. DEW POINTS
GETTING A LITTLE LOWER AHEAD OF SCHEDULE...ACROSS THE BOARD...SO
LOWERED DEW POINTS 1-3 DEG AS NEEDED. ALSO STRATOCUMULUS DECK
ACROSS NORTHERN ALABAMA AND MIDDLE TENNESSEE WILL BE SPREADING
ACROSS OUR SOUTHERN COUNTIES...LOWERED MAX TEMPS 1-2 DEG IN THOSE
AREAS. KEEPING SWRN COUNTIES DRY WITH THIS UPDATE FOR THIS
AFTERNOON. DON`T THINK SHOWERS IN MISSISSIPPI WILL MAKE IN FIRST
PERIOD...AND HRRR HAS THEM FADING ANYWAY. ALSO...MODEL SOUNDINGS
DON`T LOOK FAVORABLE FOR CONVECTIVE DEVELOPMENT...COOLER SURFACE
UNDER CLOUD COVER AND DRIER AIR ALOFT THAT WOULD GET ENTRAINED.
WILL KEEP LIGHT POPS IN EXTREME SE COUNTIES FOR NOW DUE TO POSSIBLE
EXTRA OROGRAPHIC LIFT THERE.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 84 68 87 67 / 10 10 10 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 84 65 86 65 / 10 10 10 20
OAK RIDGE, TN 85 63 86 64 / 10 0 10 20
TRI CITIES AIRPORT, TN 84 59 84 61 / 10 0 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
GM
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
807 PM CDT SAT AUG 22 2015
.UPDATE...
THE OUTFLOW BOUNDARY ALONG THE EASTERN RED RIVER COUNTIES HAS
DISSIPATED AND WINDS HAVE RETURNED TO THE SOUTH. ALL HI-RES
MODELS DO NOT SHOW ANY CONVECTION IN THE CWA OVERNIGHT AND HAVE
REMOVED POPS AREA WIDE.
TTU WRF AND HRRR MODELS DO NOT BRING THE FRONT SOUTH OF THE RED
RIVER UNTIL LATE SUNDAY AFTERNOON. THUS WE HAVE LOWERED POPS
TO 20 PERCENT SUNDAY MORNING ALONG THE RED RIVER VALLEY...AND
20-30 PERCENT SUNDAY AFTERNOON ALONG AND NORTH OF I-20. THE MOST
FAVORED AREA FOR CONVECTION SUNDAY AFTERNOON AND EVENING SHOULD BE
THOSE COUNTIES EAST OF A GAINESVILLE TO DENTON LINE. 75
&&
.AVIATION...
/ISSUED 706 PM CDT SAT AUG 22 2015/
/00Z TAFS/
CONCERNS: MINOR WITH POSSIBLE MVFR CIGS BETWEEN 12Z-15Z AT WACO...
OTHERWISE VFR.
A WEAK COLD FRONT SHOULD MOVE ACROSS THE RED RIVER LATE SUN
NIGHT/EARLY MON MORNING...WITH MODELS SHOWING VARY DEGREES OF
PUSH. IT WILL BE A CHALLENGE ON FUTURE TAFS GOING INTO SUNDAY. WE
MUST CONSIDER POSSIBLE ISOLATED-SCATTERED CONVECTIVE CHANCES NEAR
AND NE OF DFW AREA AIRPORTS NEAR THE COLD FRONT DURING THIS
PERIOD AS WELL. E/LL FINE TUNE THE FRONT AND POTENTIAL CONVECTION
AS WE HEAD INTO SUNDAY ON FUTURE FORECASTS.
SE WINDS 10-15 KTS WILL BECOME S NEAR 15 KTS BY MIDDAY SUNDAY...WITH
UNCERTAINTY ON WIND SPEED/DIRECTION LATER SUNDAY NIGHT/MONDAY MORNING
WITH THE POTENTIAL WEAK COLD FROPA.
05/
&&
.PREV DISCUSSION... /ISSUED 324 PM CDT SAT AUG 22 2015/
A COMPLEX OF THUNDERSTORMS ASSOCIATED WITH A SHORT WAVE WILL
CONTINUE MOVING ACROSS EXTREME EASTERN OKLAHOMA AND ARKANSAS
THIS AFTERNOON. SOME OF THESE STORMS WILL MOVE SOUTHEAST OF THE
MAIN COMPLEX ON AN OUTFLOW BOUNDARY AND AFFECT THE NORTHEAST ZONES
THROUGH LATE AFTERNOON.
A FEW SHOWERS AND THUNDERSTORMS ARE ALSO POSSIBLE ACROSS THE
SOUTHEAST ZONES OF NORTH TEXAS THROUGH SUNSET WHERE MOISTURE AND
INSTABILITY ARE THE MOST ABUNDANT. THIS ACTIVITY SHOULD DISSIPATE
WITH THE LOSS OF SURFACE HEATING.
AFTER SUNSET...A QUIET...WARM AND HUMID NIGHT IS STORE WITH
OVERNIGHT LOWS FROM THE MID 70S TO AROUND 80.
A COLD FRONT WILL MOVE ACROSS THE CENTRAL PLAINS OVERNIGHT AND
SUNDAY MORNING AND REACH THE RED RIVER AROUND MIDDAY. WEAK
FORCING FOR ASCENT MAY RESULT IN A FEW SHOWERS AND THUNDERSTORMS
ACROSS THE NORTHERN HALF OF NORTH TEXAS SUNDAY AFTERNOON/SUNDAY
NIGHT. HOWEVER...WEAK LARGE SCALE SUBSIDENCE MAY LIMIT OR EVEN
PREVENT STORMS FROM FORMING. THEREFORE...WE WILL KEEP ONLY 20 TO
30 PERCENT POPS IN THE FORECAST.
THE COLD FRONT WILL MOVE SLOWLY THROUGH NORTH TEXAS MONDAY THROUGH
TUESDAY AND WILL WARRANT THE MENTION OF SOME LOW POPS. THE FRONT
WILL ALSO BRING A FEW MORE CLOUDS BUT ONLY SLIGHTLY COOLER
TEMPERATURES.
UPPER LEVEL HIGH PRESSURE WILL REMAIN CENTERED OVER ARIZONA AND
NEW MEXICO WEDNESDAY THROUGH THE WEEKEND WHICH WILL KEEP NORTH
TEXAS IN DRY NORTH TO NORTHWEST FLOW ALOFT. THE EXTENDED MODELS
HAVE BEEN ADVERTISING A WEAK SHORT WAVE ON THE NORTHEASTERN
PERIPHERY OF THE UPPER RIDGE APPROACHING THE RED RIVER ON FRIDAY.
HOWEVER...MOISTURE SHOULD BE VERY LIMITED WHEN THE SHORT WAVE
ARRIVES AND PRECIPITATION SEEMS UNLIKELY AT THIS TIME.
SEASONABLY WARM TEMPERATURES ARE EXPECTED WEDNESDAY THROUGH THE
WEEKEND WITH HIGHS IN THE LOWER AND MIDDLE 90S AND LOWS IN THE
70S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 98 75 95 74 / 5 20 20 20 20
WACO, TX 78 99 77 99 74 / 5 5 5 20 20
PARIS, TX 74 95 72 91 69 / 10 40 40 20 20
DENTON, TX 78 97 70 92 71 / 5 20 30 20 20
MCKINNEY, TX 77 97 73 93 69 / 5 30 30 20 20
DALLAS, TX 80 99 77 96 76 / 5 20 20 20 20
TERRELL, TX 78 99 73 97 71 / 5 20 20 20 20
CORSICANA, TX 78 98 76 99 75 / 5 10 10 20 20
TEMPLE, TX 76 98 76 99 75 / 0 5 5 20 10
MINERAL WELLS, TX 74 99 71 94 70 / 5 10 20 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/75
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
641 PM CDT SAT AUG 22 2015
.AVIATION...
/00Z TAFS/
MVFR stratus likely along the I-20 corridor, affecting KSOA and
KJCT late tonight through mid morning Sunday. Otherwise VFR with
southeast to south winds 12 KTs or less.
&&
.PREV DISCUSSION... /ISSUED 318 PM CDT SAT AUG 22 2015/
SHORT TERM...
(Tonight and Sunday)
A few diurnal thunderstorms have developed over the Davis Mountains
this afternoon with only sparse cu field and a few high clouds over
West Central TX. Temperatures have warmed into the mid/upper 90s
with dewpoints holding in the low/mid 60s. Generally quiet weather
conditions are expected tonight across the area with the cu field
dissipating with the setting sun. The HRRR has been insistent on
developing some convection west of San Angelo late this afternoon,
but this solution has been dismissed as an outlier, especially given
the lack of a focused cu field this afternoon. Tonight, expect
temperatures to drop into the mid 70s with southerly winds remaining
in the 6-12 mph range. Winds could become gusty for a few hours
tonight, especially in the higher terrain as the low-level jet sets
up.
A weak cold front will move south into the Big Country on Sunday.
The general consensus is that this front will move as far south as a
Sterling City to Eastland line by early afternoon, likely stalling
out for the remainder of the day. Temperatures are expected to be a
few degrees cooler (low/mid 90s) behind this boundary, with highs
likely in the mid/upper 90s to the south. Scattered showers and
thunderstorms are expected to develop during the afternoon in the
vicinity of this cold front. While organized severe weather is not
anticipated, high cloud bases will yield a potential microburst
environment.
Johnson
LONG TERM...
(Sunday night through Saturday)
A weak cold front will be located across the Big Country Sunday
evening, then slowly move south. Along and behind the front,
isolated to scattered showers will be possible, with the best chance
north of Interstate 20. The front will slowly progress south
reaching the Concho Valley/Heartland Monday morning. The front will
serve as the focus for additional isolated showers and thunderstorms
on Monday, mainly north of a Mertzon, to Menard, to Mason line.
Much of the rest of the extended forecast will be characterized by
an upper level ridge centered over the Desert Southwest, with West
Central Texas in northwest to north flow aloft. The forecast
generally looks to remain dry, but given the northerly flow aloft,
any embedded upper level shortwave troughs (disturbances) could
result in at least isolated convection for portions of the area. The
first opportunity for showers and thunderstorms will be Tuesday as
disturbance in the northwest flow aloft traverses the area. This is
depicted most aggressively by the ECMWF, with the best PoPs across
the eastern half of the area. The next opportunity for rainfall will
be Friday into next weekend, as another cold front approaches the
area. The best PoPs look to be across the Big Country at this time.
In conclusion, the timing and strength of any disturbances is hard
to pinpoint this far in advance, but the overall theme for the
upcoming week is for dry conditions to persist.
Temperatures through much of the upcoming work week will be above
normal. Highs will generally be in the mid to upper 90s, although a
few locations may approach the century mark, especially during the
first part of the week. Overnight lows will generally be in the 70s,
with a few locations dropping into the upper 60s.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 76 97 73 94 / 5 20 30 20
San Angelo 76 101 74 98 / 5 10 10 20
Junction 75 99 74 98 / 5 5 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
99/99/04
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
603 PM CDT FRI AUG 21 2015
.DISCUSSION...SEE 00Z AVIATION DISCUSSION.
&&
.AVIATION...CONVECTION COMING TO AN END AND/OR MOVING OUT OF
AREA. THINK KLRD WILL NOT SEE ANYTHING...BUT WILL MAKE ANY CHANGE
IF NEEDED. THINK WITH MID/HIGH CLOUD COVER STILL EXPECTED...MVFR
CIGS MAY BE HARD TO COME BY EXCEPT AT KVCT...WHERE MVFR CIGS
COULD RESULT DUE TO SUSTAINED FLOW FROM THE GULF. OTHERWISE...WILL
KEEP MVFR CIGS (TEMPO) IN KALI AND KLRD BEFORE 14Z (NEXT
FORECASTER CAN DECIDE)...THEN SHOULD HAVE VFR. WITH TROUGH TO
EAST AND WINDS KICKING UP...THINK CONVECTION WILL BE VERY LIMITED.
WILL MENTION VCSH/VCTS FOR KVCT AND KCRP WHERE MOISTURE IS BETTER
BUT NOTHING ANYWHERE ELSE (AND NO TEMPOS OR PROB30). SOUTH WINDS
KICK UP ON SATURDAY AFTER 15Z...AND BECOME SSE IN THE AFTERNOON
BEHIND THE SEA-BREEZE.
&&
.PREV DISCUSSION... /ISSUED 329 PM CDT FRI AUG 21 2015/
SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...ATMOSPHERE HAS
RECENTLY RECOVERED FROM CONVECTION EARLIER THIS MORNING. SHOWERS
AND THUNDERSTORMS ARE NOW BEGINNING TO DEVELOP ALONG THE SEA
BREEZE. A FEW OF THESE THUNDERSTORMS HAVE THE POTENTIAL TO BECOME
STRONG AS MLCAPES ARE AOA 2000 J/KG PER SPC MESOANALYSIS PAGE.
GUSTY WINDS AND LOCALLY HEAVY DOWNPOURS WOULD BE THE MAIN IMPACTS
FROM THESE STORMS. MOST OF THIS ACTIVITY SHOULD BE DIURNALLY
DRIVEN AND LATEST RUN OF THE HRRR SUPPORTS THIS. WILL ONLY CARRY
20 POPS AFTER 00Z. AS WITH THE LAST COUPLE OF MORNINGS...
CONVECTION MAY REDEVELOP OVER THE GULF WATERS LATE TONIGHT INTO
EARLY SATURDAY MORNING. SHOWERS AND STORMS WILL THEN MOVE INLAND
WITH SEA BREEZE DURING THE AFTERNOON...WHICH IS HANDLED WELL IN
THE CURRENT FORECAST. TEMPERATURES WILL REBOUND ON SATURDAY WITH
HIGHS NEAR 100 OVER THE RIO GRANDE PLAINS TO LOWER/MIDDLE 90S
ACROSS THE COASTAL BEND. OVERNIGHT LOWS WILL CONTINUE TO BE ON THE
WARM SIDE...WITH TEMPS IN THE MID/UPPER 70S AND LOWER 80S ALONG
THE IMMEDIATE COAST.
LONG TERM (SUNDAY THROUGH FRIDAY)...MID LEVEL HIGH PRESSURE ACROSS
THE DESERT SOUTHWEST AND ACROSS THE GULF BEGIN TO MERGE TOGETHER
ACROSS THE SOUTHERN PLAINS SUNDAY...ALLOWING FOR RIDGING TO BUILD
ACROSS SOUTH TEXAS. REMNANTS OF THE EARLIER TROUGH LIFT TO THE NORTH
AND EAST...BUT SEND OUT AN IMPULSE OF ENERGY SOUTHWARD MONDAY. AT
THE SURFACE...LOW PRESSURE ACROSS THE HIGH PLAINS SWINGS EAST
PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS AND GREAT LAKES
REGION. ALTHOUGH THE MAIN FRONT IS NOT EXPECTED TO MOVE THROUGH
SOUTH TEXAS...WITH THE MID LEVEL IMPULSE WILL AIDING IN FURTHER
SOUTHEASTWARD PROGRESSION OF THE FRONT...AND HIGH PRESSURE WILL
BEGIN TO BUILD INTO THE SOUTHERN STATES. MOISTURE POOLING ALONG THE
SOUTHERN PERIPHERY OF THE HIGH WITH PWATS NEAR 1.9 INCHES...WILL
BRING RAIN CHANCES TUESDAY AND WEDNESDAY. THIS BOUNDARY WILL ALLOW
FOR WINDS TO BECOME LIGHT AND VARIABLE BY TUESDAY...WITH THE COASTAL
PLAINS WINDS MORE INFLUENCED ON DIURNAL THERMAL DIFFERENCES...WITH A
LIGHT LAND BREEZE OVERNIGHT SWITCHING OUT OF THE EAST TO SOUTHEAST
IN THE AFTERNOON DUE TO THE SEA BREEZE. A MORE PERSISTENT
SOUTHEASTERLY FLOW WILL REDEVELOP HEADING INTO THURSDAY NIGHT.
NOTICEABLE DIURNAL FLUCTUATIONS WITH TEMPERATURES ARE ALSO
EXPECTED...ESPECIALLY AFTER WEDNESDAY...AS THE DRIER AIR AND CLEARER
SKIES SHOULD CONTINUE TO ALLOW DAYTIME TEMPS TO REACH INTO THE MID
TO UPPER 90S AND ALSO RESULT IN OVERNIGHT LOWS DIPPING INTO THE
LOWER 70S.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 79 93 79 94 76 / 20 20 10 20 10
VICTORIA 76 94 76 96 75 / 20 30 10 20 10
LAREDO 78 100 78 101 77 / 20 20 10 10 10
ALICE 76 96 76 96 75 / 20 30 10 20 10
ROCKPORT 80 91 81 91 79 / 20 20 10 20 10
COTULLA 77 99 77 100 76 / 20 20 10 10 10
KINGSVILLE 78 95 78 96 76 / 20 20 10 20 10
NAVY CORPUS 80 89 81 91 80 / 20 20 10 20 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
GW/86...LONG TERM
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
335 PM CDT FRI AUG 21 2015
.SHORT TERM...
(Tonight and Saturday)
Skies were mostly sunny across West Central Texas this afternoon
with south winds of 10 to 15 mph. The conditions were humid with
dewpoints in the 60s at 19Z. Temperatures across the area were in
the lower to mid 90s. Keeping an eye on a vort max (per WV
imagery) over southeast Colorado, with subtle trough axis
extending south into west Texas.
The combination of mid and upper ascent from the upper level
feature, moderate instability and a surface trough will lead to
scattered thunderstorms developing across the Texas Panhandle and
South Plains late this afternoon and evening. All of the
convective allowing models (TX Tech WRF, HRRR and 4km NMM)
indicate scattered cells merging into a few small convective
complexes and moving east-southeast toward western Oklahoma and
northwest Texas this evening into the early morning hours. The Big
Country has the best chance of seeing thunderstorms tonight,
mainly after 02Z. A few storms may produce strong wind gusts along
with dangerous lightning. Going with slight chance to chance Pops
generally north of Sterling City to Brownwood line for tonight,
with the highest numbers north of the I-20 corridor. Lows will be
70 to 75.
For Saturday, going with a dry and hot forecast as low level
southerly flow will persist. Highs will be 95 to 100. There will
be widespread low clouds across much of the area during the
morning, mostly dissipating by 17Z.
21
.LONG TERM...
(Saturday night through Friday)
Generally quiet weather conditions are anticipated Saturday night.
The low-level jet will intensify by mid-evening, keeping southerly
winds up at 10-15 mph overnight. This will help maintain a moist
boundary layer and keep overnight lows in the mid 70s. We may also
see low stratus develop over the Hill Country, but its northward
extent should remain limited. A cold front will move south across
the South Plains early Sunday and is expected to move into the Big
Country during the afternoon hours. Temperatures across the Big
Country will depend on how fast (and how far south) the front
advances on Sunday afternoon, but for now it appears that highs
will be in the mid to upper 90s across most of the area.
There is a chance for showers and thunderstorms, mainly along and
north of the front (across the Big Country), Sunday afternoon.
This boundary is forecast to move slowly south Sunday night and
early Monday, eventually stalling between I-10 and I-20. Again,
the best rain chances will be focused along and north of the
front. However, with an east-northeast steering flow, slight
chance PoPs were warranted farther south and west of the boundary,
covering most of the CWA. Temperatures should be a few degrees
cooler on Monday, and may need to be lowered a few degrees
further.
Rain chances will continue areawide on Tuesday as the quasi-
stationary front persists over the CWA. Temperatures should again
be in the vicinity of climatology with lows in the low/mid 70s
and highs in the mid 90s. By midweek, the subtropical ridge is
expected to become the dominate synoptic feature over the High
Plains. This should result in dry conditions Wednesday and
Thursday, with temperatures likely moving back into the mid/upper
90s. Both the ECMWF and GFS indicate a fairly potent shortwave
moving southeast into the Southern Plains Thursday night into
Friday. This could result in additional rain chances, but the
forecast was left dry for now. Will continue to watch how this
feature is handled by subsequent model runs.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 73 98 75 96 / 20 5 5 20
San Angelo 73 100 75 99 / 10 5 0 10
Junction 73 97 75 98 / 10 5 0 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
21/25
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
329 PM CDT FRI AUG 21 2015
.SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...ATMOSPHERE HAS
RECENTLY RECOVERED FROM CONVECTION EARLIER THIS MORNING. SHOWERS
AND THUNDERSTORMS ARE NOW BEGINNING TO DEVELOP ALONG THE SEA
BREEZE. A FEW OF THESE THUNDERSTORMS HAVE THE POTENTIAL TO BECOME
STRONG AS MLCAPES ARE AOA 2000 J/KG PER SPC MESOANALYSIS PAGE.
GUSTY WINDS AND LOCALLY HEAVY DOWNPOURS WOULD BE THE MAIN IMPACTS
FROM THESE STORMS. MOST OF THIS ACTIVITY SHOULD BE DIURNALLY
DRIVEN AND LATEST RUN OF THE HRRR SUPPORTS THIS. WILL ONLY CARRY
20 POPS AFTER 00Z. AS WITH THE LAST COUPLE OF MORNINGS...
CONVECTION MAY REDEVELOP OVER THE GULF WATERS LATE TONIGHT INTO
EARLY SATURDAY MORNING. SHOWERS AND STORMS WILL THEN MOVE INLAND
WITH SEA BREEZE DURING THE AFTERNOON...WHICH IS HANDLED WELL IN
THE CURRENT FORECAST. TEMPERATURES WILL REBOUND ON SATURDAY WITH
HIGHS NEAR 100 OVER THE RIO GRANDE PLAINS TO LOWER/MIDDLE 90S
ACROSS THE COASTAL BEND. OVERNIGHT LOWS WILL CONTINUE TO BE ON THE
WARM SIDE...WITH TEMPS IN THE MID/UPPER 70S AND LOWER 80S ALONG
THE IMMEDIATE COAST.
&&
.LONG TERM (SUNDAY THROUGH FRIDAY)...MID LEVEL HIGH PRESSURE ACROSS
THE DESERT SOUTHWEST AND ACROSS THE GULF BEGIN TO MERGE TOGETHER
ACROSS THE SOUTHERN PLAINS SUNDAY...ALLOWING FOR RIDGING TO BUILD
ACROSS SOUTH TEXAS. REMNANTS OF THE EARLIER TROUGH LIFT TO THE NORTH
AND EAST...BUT SEND OUT AN IMPULSE OF ENERGY SOUTHWARD MONDAY. AT
THE SURFACE...LOW PRESSURE ACROSS THE HIGH PLAINS SWINGS EAST
PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS AND GREAT LAKES
REGION. ALTHOUGH THE MAIN FRONT IS NOT EXPECTED TO MOVE THROUGH
SOUTH TEXAS...WITH THE MID LEVEL IMPULSE WILL AIDING IN FURTHER
SOUTHEASTWARD PROGRESSION OF THE FRONT...AND HIGH PRESSURE WILL
BEGIN TO BUILD INTO THE SOUTHERN STATES. MOISTURE POOLING ALONG THE
SOUTHERN PERIPHERY OF THE HIGH WITH PWATS NEAR 1.9 INCHES...WILL
BRING RAIN CHANCES TUESDAY AND WEDNESDAY. THIS BOUNDARY WILL ALLOW
FOR WINDS TO BECOME LIGHT AND VARIABLE BY TUESDAY...WITH THE COASTAL
PLAINS WINDS MORE INFLUENCED ON DIURNAL THERMAL DIFFERENCES...WITH A
LIGHT LAND BREEZE OVERNIGHT SWITCHING OUT OF THE EAST TO SOUTHEAST
IN THE AFTERNOON DUE TO THE SEA BREEZE. A MORE PERSISTENT
SOUTHEASTERLY FLOW WILL REDEVELOP HEADING INTO THURSDAY NIGHT.
NOTICEABLE DIURNAL FLUCTUATIONS WITH TEMPERATURES ARE ALSO
EXPECTED...ESPECIALLY AFTER WEDNESDAY...AS THE DRIER AIR AND CLEARER
SKIES SHOULD CONTINUE TO ALLOW DAYTIME TEMPS TO REACH INTO THE MID
TO UPPER 90S AND ALSO RESULT IN OVERNIGHT LOWS DIPPING INTO THE
LOWER 70S.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 79 93 79 94 76 / 20 20 10 20 10
VICTORIA 76 94 76 96 75 / 20 30 10 20 10
LAREDO 78 100 78 101 77 / 20 20 10 10 10
ALICE 76 96 76 96 75 / 20 30 10 20 10
ROCKPORT 80 91 81 91 79 / 20 20 10 20 10
COTULLA 77 99 77 100 76 / 20 20 10 10 10
KINGSVILLE 78 95 78 96 76 / 20 20 10 20 10
NAVY CORPUS 80 89 81 91 80 / 20 20 10 20 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TB/78...SHORT TERM
CB/85...LONG TERM
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
319 PM CDT FRI AUG 21 2015
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...UPPER LEVEL TROUGH
REMAINS OVER THE AREA PUMPING IN HIGH LEVELS OF MOISTURE INTO THE
AREA. IN FACT...12Z BRO SOUNDING SHOWED PWATS OF 2.3 INCHES. EARLY
MORNING MID/HIGH CLOUDS STUNTED DIURNAL TEMPERATURE RISE IN THE
MID/LOWER VALLEY SO ADJUSTED HOURLY TEMPERATURE GRIDS DOWN AND
SHAVED A DEGREE OF THE HIGHS. STILL EXPECT 90S TODAY WITH UPPER 90S
OUT IN OUR WESTERN SECTIONS. CUMULUS FIELD IS SLOW TO DEVELOP AND IS
NOW BECOMING AGITATED ACROSS THE RANCHLANDS OF BROOKS AND EASTERN
JIM HOGG COUNTIES. IN THE VALLEY...JUST NOW BEGINNING TO SEE CUMULUS
DEVELOPMENT UNDERNEATH REMAINING MID/HIGH CLOUD DECKS. MOS GUIDANCE
HAS LOWERED POPS IN THE VALLEY AND HAVE FOLLOWED SUIT AND HAVE LEFT
INHERITED POPS AS IS FOR THIS AFTERNOON. HRRR SHOWS DEVELOPMENT
IMMINENT IN THE RANCHLANDS WITH SHOWERS/STORMS MOVING WESTWARD WITH
TIME INTO OUR WESTERN SECTIONS EARLY THIS EVENING BEFORE DISSIPATING
BY MID EVENING. OVERNIGHT CONVECTION WILL DEVELOP OVER THE COASTAL
WATERS BUT SHOULD NOT BE AS WIDESPREAD AS LAST NIGHT. LOW/MID CLOUDS
EXPECTED TO DEVELOP OVERNIGHT WITH MOSTLY CLOUDY SKIES BY DAYBREAK
HOLDING UP LOW TEMPERATURES CLOSER TO 80 DEGREES IN THE VALLEY.
UPPER TROUGH WEAKENS SATURDAY AND BEING REPLACED BY EXPANDING UPPER
LEVEL RIDGING AND LOWER PWATS LEADING TO LOWER CHANCES FOR
PRECIPITATION SATURDAY AND SATURDAY NIGHT. TIME HEIGHTS AND CROSS
SECTIONS DEPICT MAINLY LOW LEVEL MOISTURE WITH A DRYING MID LEVEL
COLUMN. THERE IS A CHANCE FOR A FEW SHOWERS SATURDAY BUT SHOULD
REMAIN ISOLATED. THERE WILL AN UPTICK IN THE WINDS WITH SFC HIGH
PRESSURE IN THE NORTHERN GULF AND LOW PRESSURE ACROSS THE HIGH
PLAINS. HIGH TEMPERATURES WILL BE WARMER AS WELL WITH HIGHS AROUND
100 IN THE FAR WEST TO MID 90S IN THE LOWER VALLEY.
.LONG TERM /SUNDAY THROUGH FRIDAY/...THE 500 MB RIDGING WILL
BUILD OVER THE REGION THROUGHOUT NEXT WEEK AS TROFFING BUILDS
OVER THE EASTERN STATES. THE GFS PRODUCES A DRIER SOLUTION VERSUS
THE ECMWF WITH THE EURO MODEL BRINGING A PRETTY STRONG 500 MB VORT
MAX AROUND THE EAST SIDE OF THE RIDGE WHICH CRANKS OUT MUCH HIGHER
POPS FOR THE RGV AROUND MIDWEEK. THE GFS HAS BEEN CONSISTENTLY DRY
OVER THE LAST SEVERAL RUNS SO AM A LITTLE SCEPTICAL OF THE WETTER
ECMWF SOLUTION AT THIS TIME. WILL SEE IF FUTURE RUNS OF THE ECMWF
MAINTAIN THE WET BIAS BEFORE JUMPING TO HIGHER POPS IN THE LONGER
RANGE. SO WILL GO WITH SLGT CHC POPS AT THIS TIME. SINCE
CONFIDENCE LEVEL IN THE LONGER RANGE NUMERICAL GUIDANCE IS A BIT
LOWER TODAY WILL OPT FOR A GENERAL BLEND OF THE GFS MEX MOS TEMPS
AND THE ECMWF TEMPS.
&&
.MARINE...NOW THROUGH SATURDAY NIGHT...SEAS WERE NEAR 3 FEET WITH
SOUTHEAST WINDS NEAR 14 KNOTS AT BUOY020 THIS AFTERNOON. MODERATE
SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL WATERS AS HIGH
PRESSURE ACROSS THE NORTHERN GULF OF MEXICO AND LOW PRESSURE ACROSS
WEST TEXAS WILL KEEP A STEADY SOUTHEAST WIND GOING ACROSS THE
COASTAL WATERS. WINDS AND SEAS WILL BE HIGHER IN AND AROUND AND
SHOWERS AND STORMS.
SUNDAY THROUGH WEDNESDAY...A STATIONARY FRONT WILL DRIFT SOUTH
OVER THE GULF COAST AND THE NORTHERN GULF OF MEXICO THROUGHOUT
EARLY NEXT WEEK. AS THIS FRONT SAGS SOUTHWARDS THE PGF WILL WEAKEN
SOMEWHAT ALLOWING FOR FAIRLY LOW WINDS AND SEAS TO PREVAIL ACROSS
THE BAY AND GULF WATERS. NO SCA CONDITIONS EXPECTED THROUGH
WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 80 94 80 92 / 20 20 10 10
BROWNSVILLE 79 94 79 93 / 20 20 10 10
HARLINGEN 79 97 79 96 / 20 20 10 10
MCALLEN 79 98 80 99 / 20 20 10 10
RIO GRANDE CITY 78 99 78 100 / 30 20 10 10
SOUTH PADRE ISLAND 81 88 81 87 / 20 20 10 20
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...55
LONG TERM...60
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1237 PM CDT FRI AUG 21 2015
.AVIATION...
AFTER SPENDING MUCH OF THE MORNING IN IFR CONDITIONS ACROSS THE
I-35 CORRIDOR AND MVFR CONDITIONS AT DRT CLOUDS ARE BEGINNING TO
BREAK. AS OF A FEW MOMENTS AGO MVFR CONDITIONS NOW PREVAIL AT ALL
4 TERMINALS. THESE CIGS SHOULD STICK AROUND FOR ANOTHER HOUR OR
TWO BUT CLOUDS ARE THINNING FROM WEST TO EAST SO VFR CONDITIONS
SHOULD BREAK OUT AT ALL TERMINALS BY 20Z.
MORNING RAINFALL HAS MOVED NORTH OF AUS AND PRECIPITATION TO THE
SOUTH OF AUS AND EAST OF SAT SHOWS SIGNS OF WEAKENING. WILL NOT
CARRY ANY MENTION OF PRECIPITATION IN THE AFTERNOON TAFS AS
CHANCES WILL BE DECREASING THROUGH THE DAY.
WINDS WILL BE SOUTHEASTERLY THROUGH THE TAF PERIOD. WITH THE SUN
HELPING TO MIX OUT SOME MOISTURE THIS AFTERNOON SHOULD NOT SEE A
REPEAT OF THIS MORNINGS CIGS. WILL SEE MORNING MVFR STRATUS THOUGH
BEGINNING AROUND 09Z AND BREAKING AROUND 17Z SATURDAY MORNING AT
THE I-35 TERMINALS. DRT MAY SEE SOME HIGH END MVFR STRATUS AS
WELL.
&&
.PREV DISCUSSION... /ISSUED 935 AM CDT FRI AUG 21 2015/
UPDATE...
EARLY MORNING SHOWERS AND THUNDERSTORMS OVER THE COASTAL AREAS HAS
SENT AN OUTFLOW THAT GENERATED SHOWERS AND THUNDERSTORMS OVER THE
EASTERN PARTS OF SOUTH CENTRAL TEXAS. HAVE BOOSTED POPS 10 TO 20
PERCENT ACROSS AREAS EAST OF I-35 TO ACROSS THE AUSTIN AREA INTO
THE NORTHEASTERN HILL COUNTRY. DUE TO CLOUDS AND RAIN LINGERING
INTO THE AFTERNOON DUE TO BEING ON THE EASTERN SIDE OF THE MID TO
UPPER LEVEL SHEAR AXIS...HAVE ALSO LOWERED TEMPERATURES SLIGHTLY.
REMAINDER OF SOUTH CENTRAL TEXAS FORECAST IS ON TRACK.
PREV DISCUSSION... /ISSUED 650 AM CDT FRI AUG 21 2015/
AVIATION.../12Z TAF CYCLE/
LOWER CIGS HAVE FILLED IN AS EXPECTED THIS MORNING WITH WIDESPREAD
MVFR WITH INTERMINGLED IFR CONDITIONS PRESENT ACROSS CENTRAL TAF
SITES WITH KDRT MVFR AS WELL. AMPLE MOISTURE IN THE LOWER LAYERS WILL
TAKE SOME TIME TO MIX OUT THROUGH 15-17Z WITH A GRADUAL IMPROVEMENT
THROUGH MVFR TO EVENTUAL VFR FALL ALL SITES BY LATE MORNING TO EARLY
AFTERNOON. A COMPLEX OF SHOWERS AND STORMS IS MOVING INLAND NEAR
KVCT BUT WILL LIKELY MISS THE CENTRAL SITES. FEEL MOST SCATTERED
ACTIVITY WILL REMAIN SOUTHEAST OF THE MAIN TERMINALS AND HAVE
REFRAINED FROM VCTS WORDING THIS TAF CYCLE. TRENDS WILL NEED TO BE
MONITORED HOWEVER FOR POSSIBLE INCLUSION ON 18Z CYCLE. SURFACE WINDS
ARE LIGHT AND VARIABLE CURRENTLY BUT WILL PICK UP TO 10-15 KT THIS
AFTN FROM THE SOUTHEAST TO SOUTH DIRECTION.
PREV DISCUSSION... /ISSUED 333 AM CDT FRI AUG 21 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...
A N-S ORIENTED SHEAR AXIS MOST NOTABLE IN THE MID LEVELS OVER S TX
AND ADJACENT AREAS OF NERN MEXICO SHOULD BRING ANOTHER DAY OF
CONVECTION AND MODERATED DAYTIME TEMPERATURES FOR THE EASTERN
HALF OF SOUTH CENTRAL TX. WHILE THE FRONTAL ZONE THAT BROUGHT WELL
BELOW NORMAL MAX TEMPS TO THE AREA THURSDAY HAS RETREATED
NORTH...SOME COASTAL TROUGHING IS STILL NOTED NEAR CRP...AND A
SMALL COMPLEX OF STORMS CONFIRMS THE UNSTABLE ENVIRONMENT THAT
COULD SPREAD INLAND LATER THIS MORNING. RAPID REFRESH MODEL RUNS
DEPICT EARLY DESTABILIZATION NEAR AND EAST OF I-35 TODAY...BUT
EARLIER RUNS OF THE HRRR WERE SHOWN TO BE TOO AGGRESSIVE WITH
CONVECTION IN THE PRE-DAWN HOURS. ADDITIONAL MOISTURE AND POSSIBLE
INSTABILITY IS MOVING IN FROM NW FLOW ALOFT FROM WEST TX...BUT
WITH ONLY THE 00Z NSSL WRF MODEL SHOWING AN IMPACT OVER OUR
WESTERN COUNTIES VERSUS SEVERAL THAT DO NOT...WILL STICK WITH THE
CONSENSUS POPS FOR THE SERN TWO-THIRDS OF THE FORECAST AREA.
BLENDED GUIDANCES CONTAIN ARTIFACTS OF EARLIER FORECAST HIGHER
TEMPS...SO OPTED FOR A BLEND OF MAV/MET FOR HIGHS.
MODEL RUN TO RUN TRENDS IN THE EARLY PERIODS SHOW MORE SHEAR THAN
EARLIER RUNS...SO WILL FOLLOW THIS TREND TO KEEP A SLIGHTLY LESS
STABLE PICTURE FOR OUR SOUTHERN/WRN COUNTIES FOR SATURDAY.
INCREASED RIDGING AND DRY AIR ENTRAINMENT FROM THE NORTH SHOULD
PRECLUDE CONVECTION OVER MOST OF SOUTH CENTRAL TEXAS...BUT THE
WESTWARD SHIFTING SHEAR AXIS SHOULD PULL SOME MOISTURE WITH IT TO
BRING A SLIGHT CHANCE OF DAYTIME CONVECTION OVER THE RIO GRANDE
PLAINS. MEANWHILE SOUTHERN PARTS OF THE COASTAL PLAINS LOSE THE
CYCLONIC SHEAR BUT MAINTAIN LOCALLY HIGHER PWAT VALUES FOR ONE
MORE DAY. WILL FAVOR THE GFS BASED GUIDANCE FOR WARMER TEMPS TO
REGAIN CONTROL OVER CENTRAL TX WHERE THE DRIER AND MORE STABLE MID-
LEVEL AIR MOVES IN.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE BRIEF BREAK FROM THE HEAT IS ALL BUT FORGOTTEN BY SUNDAY. THE
GFS AND ECMWF BOTH BUILD A STRONG RIDGE OVER THE SOUTHERN ROCKIES
WITH AN AXIS THAT EXTENDS SE ACROSS CENTRAL TX. WILL SHADE TOWARD
THE HIGHER MEX GUIDANCE ON MAXES SUNDAY THROUGH WEDNESDAY AS
AUGUST RAINS HAVE BEEN MOSTLY TOO SPARSE TO PROVIDE FEEDBACK
THROUGH SOIL AND VEGETATION. LATE MONDAY THROUGH DAYTIME
WEDNESDAY...THERE IS A SIGNAL FOR MID-LEVEL MOISTURE POOLING TO
SPREAD SOUTH FROM NORTH TX AS NORTHERLY FLOW INCREASES ALOFT. THUS
WILL SHADE TOWARD THE SLIGHTLY MORE UNSTABLE ECMWF OVER THE
SLIGHTLY DRIER GFS FOR THOSE DAYS. LITTLE OR NO CONVECTION IS
SHOWN BY EITHER MODEL FOR THE REMAINDER OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 91 76 98 77 99 / 40 10 10 - -
AUSTIN BERGSTROM INTL AIRPORT 92 73 97 75 98 / 40 10 10 - -
NEW BRAUNFELS MUNI AIRPORT 92 75 98 76 98 / 30 10 10 - -
BURNET MUNI AIRPORT 92 74 97 75 98 / 20 10 10 - -
DEL RIO INTL AIRPORT 96 76 98 78 99 / 10 - 20 - -
GEORGETOWN MUNI AIRPORT 92 76 96 76 98 / 40 10 10 - 10
HONDO MUNI AIRPORT 95 74 96 75 97 / 20 10 10 - -
SAN MARCOS MUNI AIRPORT 92 75 98 76 99 / 30 10 10 - -
LA GRANGE - FAYETTE REGIONAL 91 76 96 76 98 / 50 20 20 10 10
SAN ANTONIO INTL AIRPORT 93 76 97 77 98 / 30 10 10 - -
STINSON MUNI AIRPORT 93 76 98 77 99 / 30 20 10 - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...TREADWAY
SYNOPTIC/GRIDS...04
PUBLIC SERVICE/DATA COLLECTION...10
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1236 PM CDT FRI AUG 21 2015
.DISCUSSION...UPDATED FOR 18Z AVIATION.
&&
.AVIATION...LATEST RUN OF THE HRRR RE-DEVELOPS SHOWERS AND
THUNDERSTORMS ACROSS SOUTH TEXAS THIS AFTERNOON. WILL HANDLE THE
POTENTIAL FOR CONVECTION WITH VCTS REMARKS FOR NOW AND WILL AMEND
AS NECESSARY. VFR CONDITIONS INITIALLY WILL THEN TRANSITION TO
MVFR LEVELS OVERNIGHT INTO EARLY SATURDAY MORNING. LOW CLOUDS
SHOULD MIX OUT AROUND 14Z/15Z WITH A RETURN TO VFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 905 AM CDT FRI AUG 21 2015/
DISCUSSION...INCREASED POPS ACROSS THE MIDDLE TEXAS COASTAL
WATERS AND IMMEDIATE COASTAL COUNTIES BASED ON LATEST RADAR
TRENDS.
PREV DISCUSSION... /ISSUED 645 AM CDT FRI AUG 21 2015/
DISCUSSION...NOTE AVIATION DISCUSSION BELOW.
AVIATION...A MIXTURE OF VFR/MVFR CEILINGS WL PERSIST THIS MORNING
DRG AND OUTSIDE OF ISOLATED/SCATTERED SHOWERS OVER THE COASTAL
BEND/OFFSHORE. CONTINUE TO ANTICIPATE THE DEVELOPMENT OF
SCATTERED SHOWERS AND THUNDERSTORMS DRG THE LATE MORNING/AFTERNOON
OVER LAND MAINLY EAST OF U.S. ROUTE 281. EXPECT CONVECTION TO
THEN MOVE GENERALLY WEST OF U.S. ROUTE 281 DRG THE EVENING.
NOCTURNAL CONVECTION EXPECTED AGAIN OVERNIGHT NEAR THE
COAST/OFFSHORE. GENERALLY LGT/VARIABLE WIND EARLY THIS MORNING
TRANSITIONING TO MODERATE ONSHORE FLOW DRG THE MID/LATE AFTN
HOURS TODAY. BECOMING LGT AGAIN OVERNIGHT.
PREV DISCUSSION... /ISSUED 601 AM CDT FRI AUG 21 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...CONVECTION EARLY THIS
MORNING OVER THE MSA/ERN CWA NEAR A SFC TROUGH. GFS/NAM
STREAMLINES DEPICT AN UPPER TROUGH AXIS OVER THE ERN CWA. GOES
SOUNDER DPI PWAT SUGGEST COPIOUS MSTR OVER THE CWA/MSA. NAM
PREDICTS SIGNIFICANT CAPE/LOW CIN THIS AFTN. EXPECT THE
COMBINATION OF THE UPPER SYSTEM/MSTR/INSTABILITY/SEA BREEZE TO
RESULT IN SCATTERED CONVECTION TODAY. EXPECT CONVECTION TO SHIFT
TO THE WRN CWA DRG THE EVENING. CONCUR WITH THE GFS/NAM WHICH
MAINTAINS THE UPPER PATTERN TONIGHT/SATURDAY. THUS EXPECT NOCTURAL
CONVECTION TO DEVELOP AGAIN OVER THE MSA OVERNIGHT/EARLY SATURDAY
FOLLOWED BY AFTN CONVECTION OVER THE CWA.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...THE UPPER LEVEL
TROUGH AXIS IS PROGD TO SHIFT FARTHER W SAT NIGHT/SUN WITH HIGH
PRESSURE BUILDING ACROSS S TX FROM THE NE AND E. THIS WILL BRING
DRIER AIR TO S TX...BUT STILL SUFFICIENT MOISTURE FOR ISOLD SEA
BREEZE CONVECTION SUN AFTERNOON. THE HIGH PRESSURE ALOFT IS PROGD TO
REMAIN IN CONTROL THROUGH THE REMAINDER OF NEXT WEEK WITH ONLY ISOLD
CONVECTION EXPECTED ON TUE ACROSS THE NE AND E CWA DUE TO A WEAK
SHORT WAVE ROUNDING THE SE PERIPHERY OF THE RIDGE.
OTHERWISE...GENERALLY DRY FCST FOR THE EXTENDED. TEMPS ARE EXPECTED
TO BE NEAR NORMAL NEXT WEEK ALONG WITH A WEAK TO OCCASIONALLY MOD
ONSHORE FLOW. MODELS DO SHOW VERY LIGHT OFFSHORE WINDS EACH
NIGHT/EARLY MORNING THROUGH MUCH OF NEXT WEEK WHICH WILL HELP KEEP
MN TEMPS A TAD COOLER THAN THIS PAST WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 78 93 79 94 78 / 20 20 10 20 10
VICTORIA 76 94 76 95 76 / 20 30 10 20 10
LAREDO 78 99 78 101 77 / 20 20 10 10 10
ALICE 76 96 77 96 76 / 20 30 10 20 10
ROCKPORT 80 90 81 91 80 / 20 20 10 20 10
COTULLA 75 98 76 100 76 / 20 20 10 10 10
KINGSVILLE 77 95 78 95 77 / 20 20 10 20 10
NAVY CORPUS 80 89 81 90 80 / 20 20 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TB/78...AVIATION
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
935 AM CDT FRI AUG 21 2015
.UPDATE...
EARLY MORNING SHOWERS AND THUNDERSTORMS OVER THE COASTAL AREAS HAS
SENT AN OUTFLOW THAT GENERATED SHOWERS AND THUNDERSTORMS OVER THE
EASTERN PARTS OF SOUTH CENTRAL TEXAS. HAVE BOOSTED POPS 10 TO 20
PERCENT ACROSS AREAS EAST OF I-35 TO ACROSS THE AUSTIN AREA INTO
THE NORTHEASTERN HILL COUNTRY. DUE TO CLOUDS AND RAIN LINGERING
INTO THE AFTERNOON DUE TO BEING ON THE EASTERN SIDE OF THE MID TO
UPPER LEVEL SHEAR AXIS...HAVE ALSO LOWERED TEMPERATURES SLIGHTLY.
REMAINDER OF SOUTH CENTRAL TEXAS FORECAST IS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 650 AM CDT FRI AUG 21 2015/
AVIATION.../12Z TAF CYCLE/
LOWER CIGS HAVE FILLED IN AS EXPECTED THIS MORNING WITH WIDESPREAD
MVFR WITH INTERMINGLED IFR CONDITIONS PRESENT ACROSS CENTRAL TAF
SITES WITH KDRT MVFR AS WELL. AMPLE MOISTURE IN THE LOWER LAYERS WILL
TAKE SOME TIME TO MIX OUT THROUGH 15-17Z WITH A GRADUAL IMPROVEMENT
THROUGH MVFR TO EVENTUAL VFR FALL ALL SITES BY LATE MORNING TO EARLY
AFTERNOON. A COMPLEX OF SHOWERS AND STORMS IS MOVING INLAND NEAR
KVCT BUT WILL LIKELY MISS THE CENTRAL SITES. FEEL MOST SCATTERED
ACTIVITY WILL REMAIN SOUTHEAST OF THE MAIN TERMINALS AND HAVE
REFRAINED FROM VCTS WORDING THIS TAF CYCLE. TRENDS WILL NEED TO BE
MONITORED HOWEVER FOR POSSIBLE INCLUSION ON 18Z CYCLE. SURFACE WINDS
ARE LIGHT AND VARIABLE CURRENTLY BUT WILL PICK UP TO 10-15 KT THIS
AFTN FROM THE SOUTHEAST TO SOUTH DIRECTION.
PREV DISCUSSION... /ISSUED 333 AM CDT FRI AUG 21 2015/
SHORT TERM (TODAY THROUGH SATURDAY)...
A N-S ORIENTED SHEAR AXIS MOST NOTABLE IN THE MID LEVELS OVER S TX
AND ADJACENT AREAS OF NERN MEXICO SHOULD BRING ANOTHER DAY OF
CONVECTION AND MODERATED DAYTIME TEMPERATURES FOR THE EASTERN
HALF OF SOUTH CENTRAL TX. WHILE THE FRONTAL ZONE THAT BROUGHT WELL
BELOW NORMAL MAX TEMPS TO THE AREA THURSDAY HAS RETREATED
NORTH...SOME COASTAL TROUGHING IS STILL NOTED NEAR CRP...AND A
SMALL COMPLEX OF STORMS CONFIRMS THE UNSTABLE ENVIRONMENT THAT
COULD SPREAD INLAND LATER THIS MORNING. RAPID REFRESH MODEL RUNS
DEPICT EARLY DESTABILIZATION NEAR AND EAST OF I-35 TODAY...BUT
EARLIER RUNS OF THE HRRR WERE SHOWN TO BE TOO AGGRESSIVE WITH
CONVECTION IN THE PRE-DAWN HOURS. ADDITIONAL MOISTURE AND POSSIBLE
INSTABILITY IS MOVING IN FROM NW FLOW ALOFT FROM WEST TX...BUT
WITH ONLY THE 00Z NSSL WRF MODEL SHOWING AN IMPACT OVER OUR
WESTERN COUNTIES VERSUS SEVERAL THAT DO NOT...WILL STICK WITH THE
CONSENSUS POPS FOR THE SERN TWO-THIRDS OF THE FORECAST AREA.
BLENDED GUIDANCES CONTAIN ARTIFACTS OF EARLIER FORECAST HIGHER
TEMPS...SO OPTED FOR A BLEND OF MAV/MET FOR HIGHS.
MODEL RUN TO RUN TRENDS IN THE EARLY PERIODS SHOW MORE SHEAR THAN
EARLIER RUNS...SO WILL FOLLOW THIS TREND TO KEEP A SLIGHTLY LESS
STABLE PICTURE FOR OUR SOUTHERN/WRN COUNTIES FOR SATURDAY.
INCREASED RIDGING AND DRY AIR ENTRAINMENT FROM THE NORTH SHOULD
PRECLUDE CONVECTION OVER MOST OF SOUTH CENTRAL TEXAS...BUT THE
WESTWARD SHIFTING SHEAR AXIS SHOULD PULL SOME MOISTURE WITH IT TO
BRING A SLIGHT CHANCE OF DAYTIME CONVECTION OVER THE RIO GRANDE
PLAINS. MEANWHILE SOUTHERN PARTS OF THE COASTAL PLAINS LOSE THE
CYCLONIC SHEAR BUT MAINTAIN LOCALLY HIGHER PWAT VALUES FOR ONE
MORE DAY. WILL FAVOR THE GFS BASED GUIDANCE FOR WARMER TEMPS TO
REGAIN CONTROL OVER CENTRAL TX WHERE THE DRIER AND MORE STABLE MID-
LEVEL AIR MOVES IN.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE BRIEF BREAK FROM THE HEAT IS ALL BUT FORGOTTEN BY SUNDAY. THE
GFS AND ECMWF BOTH BUILD A STRONG RIDGE OVER THE SOUTHERN ROCKIES
WITH AN AXIS THAT EXTENDS SE ACROSS CENTRAL TX. WILL SHADE TOWARD
THE HIGHER MEX GUIDANCE ON MAXES SUNDAY THROUGH WEDNESDAY AS
AUGUST RAINS HAVE BEEN MOSTLY TOO SPARSE TO PROVIDE FEEDBACK
THROUGH SOIL AND VEGETATION. LATE MONDAY THROUGH DAYTIME
WEDNESDAY...THERE IS A SIGNAL FOR MID-LEVEL MOISTURE POOLING TO
SPREAD SOUTH FROM NORTH TX AS NORTHERLY FLOW INCREASES ALOFT. THUS
WILL SHADE TOWARD THE SLIGHTLY MORE UNSTABLE ECMWF OVER THE
SLIGHTLY DRIER GFS FOR THOSE DAYS. LITTLE OR NO CONVECTION IS
SHOWN BY EITHER MODEL FOR THE REMAINDER OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 91 76 98 77 99 / 40 10 10 - -
AUSTIN BERGSTROM INTL AIRPORT 92 73 97 75 98 / 40 10 10 - -
NEW BRAUNFELS MUNI AIRPORT 92 75 98 76 98 / 30 10 10 - -
BURNET MUNI AIRPORT 92 74 97 75 98 / 20 10 10 - -
DEL RIO INTL AIRPORT 96 76 98 78 99 / 10 - 20 - -
GEORGETOWN MUNI AIRPORT 92 76 96 76 98 / 40 10 10 - 10
HONDO MUNI AIRPORT 95 74 96 75 97 / 20 10 10 - -
SAN MARCOS MUNI AIRPORT 92 75 98 76 99 / 30 10 10 - -
LA GRANGE - FAYETTE REGIONAL 91 76 96 76 98 / 50 20 20 10 10
SAN ANTONIO INTL AIRPORT 93 76 97 77 98 / 30 10 10 - -
STINSON MUNI AIRPORT 93 76 98 77 99 / 30 20 10 - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...TREADWAY
SYNOPTIC/GRIDS...04
PUBLIC SERVICE/DATA COLLECTION...10
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
333 AM CDT FRI AUG 21 2015
.SHORT TERM (TODAY THROUGH SATURDAY)...
A N-S ORIENTED SHEAR AXIS MOST NOTABLE IN THE MID LEVELS OVER S TX
AND ADJACENT AREAS OF NERN MEXICO SHOULD BRING ANOTHER DAY OF
CONVECTION AND MODERATED DAYTIME TEMPERATURES FOR THE EASTERN
HALF OF SOUTH CENTRAL TX. WHILE THE FRONTAL ZONE THAT BROUGHT WELL
BELOW NORMAL MAX TEMPS TO THE AREA THURSDAY HAS RETREATED
NORTH...SOME COASTAL TROUGHING IS STILL NOTED NEAR CRP...AND A
SMALL COMPLEX OF STORMS CONFIRMS THE UNSTABLE ENVIRONMENT THAT
COULD SPREAD INLAND LATER THIS MORNING. RAPID REFRESH MODEL RUNS
DEPICT EARLY DESTABILIZATION NEAR AND EAST OF I-35 TODAY...BUT
EARLIER RUNS OF THE HRRR WERE SHOWN TO BE TOO AGGRESSIVE WITH
CONVECTION IN THE PRE-DAWN HOURS. ADDITIONAL MOISTURE AND POSSIBLE
INSTABILITY IS MOVING IN FROM NW FLOW ALOFT FROM WEST TX...BUT
WITH ONLY THE 00Z NSSL WRF MODEL SHOWING AN IMPACT OVER OUR
WESTERN COUNTIES VERSUS SEVERAL THAT DO NOT...WILL STICK WITH THE
CONSENSUS POPS FOR THE SERN TWO-THIRDS OF THE FORECAST AREA.
BLENDED GUIDANCES CONTAIN ARTIFACTS OF EARLIER FORECAST HIGHER
TEMPS...SO OPTED FOR A BLEND OF MAV/MET FOR HIGHS.
MODEL RUN TO RUN TRENDS IN THE EARLY PERIODS SHOW MORE SHEAR THAN
EARLIER RUNS...SO WILL FOLLOW THIS TREND TO KEEP A SLIGHTLY LESS
STABLE PICTURE FOR OUR SOUTHERN/WRN COUNTIES FOR SATURDAY.
INCREASED RIDGING AND DRY AIR ENTRAINMENT FROM THE NORTH SHOULD
PRECLUDE CONVECTION OVER MOST OF SOUTH CENTRAL TEXAS...BUT THE
WESTWARD SHIFTING SHEAR AXIS SHOULD PULL SOME MOISTURE WITH IT TO
BRING A SLIGHT CHANCE OF DAYTIME CONVECTION OVER THE RIO GRANDE
PLAINS. MEANWHILE SOUTHERN PARTS OF THE COASTAL PLAINS LOSE THE
CYCLONIC SHEAR BUT MAINTAIN LOCALLY HIGHER PWAT VALUES FOR ONE
MORE DAY. WILL FAVOR THE GFS BASED GUIDANCE FOR WARMER TEMPS TO
REGAIN CONTROL OVER CENTRAL TX WHERE THE DRIER AND MORE STABLE MID-
LEVEL AIR MOVES IN.
&&
.LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE BRIEF BREAK FROM THE HEAT IS ALL BUT FORGOTTEN BY SUNDAY. THE
GFS AND ECMWF BOTH BUILD A STRONG RIDGE OVER THE SOUTHERN ROCKIES
WITH AN AXIS THAT EXTENDS SE ACROSS CENTRAL TX. WILL SHADE TOWARD
THE HIGHER MEX GUIDANCE ON MAXES SUNDAY THROUGH WEDNESDAY AS
AUGUST RAINS HAVE BEEN MOSTLY TOO SPARSE TO PROVIDE FEEDBACK
THROUGH SOIL AND VEGETATION. LATE MONDAY THROUGH DAYTIME
WEDNESDAY...THERE IS A SIGNAL FOR MID-LEVEL MOISTURE POOLING TO
SPREAD SOUTH FROM NORTH TX AS NORTHERLY FLOW INCREASES ALOFT. THUS
WILL SHADE TOWARD THE SLIGHTLY MORE UNSTABLE ECMWF OVER THE
SLIGHTLY DRIER GFS FOR THOSE DAYS. LITTLE OR NO CONVECTION IS
SHOWN BY EITHER MODEL FOR THE REMAINDER OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 94 76 98 77 99 / 20 10 10 - -
AUSTIN BERGSTROM INTL AIRPORT 93 73 97 75 98 / 30 10 10 - -
NEW BRAUNFELS MUNI AIRPORT 94 75 98 76 98 / 30 10 10 - -
BURNET MUNI AIRPORT 93 74 97 75 98 / 10 10 10 - -
DEL RIO INTL AIRPORT 96 76 98 78 99 / 10 - 20 - -
GEORGETOWN MUNI AIRPORT 92 76 96 76 98 / 20 10 10 - 10
HONDO MUNI AIRPORT 95 74 96 75 97 / 20 10 10 - -
SAN MARCOS MUNI AIRPORT 93 75 98 76 99 / 30 10 10 - -
LA GRANGE - FAYETTE REGIONAL 93 76 96 76 98 / 40 20 20 10 10
SAN ANTONIO INTL AIRPORT 93 76 97 77 98 / 30 10 10 - -
STINSON MUNI AIRPORT 94 76 98 77 99 / 30 20 10 - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...ALLEN
SYNOPTIC/GRIDS...OAKS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1242 PM CDT FRI AUG 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT FRI AUG 21 2015
MOST OF THE FORECAST TIME THIS MORNING WAS ENSURING WE WERE ON TRACK
WITH RAIN CHANCES IN THE RETURN FLOW TODAY....CLOUDS ON
SATURDAY...BUT MAINLY THE SATURDAY NIGHT THUNDERSTORM THREATS AND
ANY MESSAGING THAT WILL BE NEEDED FOR THOSE OUTDOORS.
CURRENT OBSERVATIONAL DATA AS OF 21.07Z INDICATES NW-SE ORIENTED
CLOUD BANDING AROUND 10KFT ACROSS CENTRAL MN ASSOCIATED WITH
FRONTOGENESIS IN THE 800-900 MB LAYER PER LATEST RAP ANALYSIS.
TSRA AND LIGHTNING IN NWRN IA ON THE NOSE OF THE LOW-LEVEL JET PER
88D VWPS AND RAP ANALYSIS. SPC MESOANALYSIS SHOWING THAT TSRA IS
ON THE NORTHERN EXTENT OF THE MUCAPE REGION /ONLY ABOUT 250 J/KG
THERE/.
GOES FOG PRODUCT AND SURFACE OBSERVATIONS SHOW A LOWER CLOUD FIELD
OVER OK/TX SOUTH IN A RICH MOIST POOL OF SURFACE DEWPOINTS OVER
65F...AND 925MB DEWPOINTS AT 18C PER 21.00Z RAOBS. WILL HAVE TO
WATCH THIS AREA AS IT ADVECTS NORTHWARD AHEAD OF THE FRONT THAT IS
MOVING IN FOR SATURDAY NIGHT...ASSOCIATED WITH THE SHORTWAVE
TROUGH NOW WORKING SOUTHWARD THROUGH BRITISH COLUMBIA /PER GOES
WATER VAPOR/. RAP ANALYSIS INDICATES THIS SPINNER HAS A TROPOPAUSE
FOLD DOWN TO ROUGHLY 750 MB...SO A POTENT VORTEX.
SHORT TERM GUIDANCE SUPPORTS EVOLVING THE FRONTOGENESIS AND THE
LOW-LEVEL JET NOSE CONVERGENCE NORTHEAST THROUGH THE FIRST PORTION
OF TODAY INTO NRN WI BY AFTERNOON. THERE WILL LIKELY BE VERY LIGHT
RADAR RETURNS AND PER 00Z RAOB DATA...SOME PRETTY DRY AIR TO
OVERCOME BELOW THE ACCAS CLOUD BASE /10KFT/. FOR NOW...HAVE KEPT
THE HIGHER PROBABILITY DRY FORECAST. SPRINKLES OR AN ISOLATED
WETTING SHOWER MAY BE POSSIBLE WITH FORCING EVOLUTION NEWRD.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT FRI AUG 21 2015
NO BIG CHANGES DURING THIS PERIOD.
SOUTHWESTERLY FLOW WILL PREVAIL SATURDAY AND PRE-FRONTALLY WILL
NEED TO WATCH THE SURGE OF 925 MB MOISTURE NORTHWARD TONIGHT.
CONSENSUS 21.00Z GUIDANCE SUGGESTS THIS TONGUE REMAINS WEST OF THE
AREA UNTIL FRONT ARRIVES SAT EVENING. HAVE INCREASED WIND GUSTS
SATURDAY WITH STRONGER LOW-LEVEL WIND FIELD SUGGESTED AND MIXING
DEPTH INTO THE 35-38KT CONSENSUS 900MB WINDS.
TIMING IS ABOUT THE SAME AS PREVIOUS FORECASTS FOR FRONT TO
BECOME ACTIVE TO THE WEST OF THE AREA LATER SATURDAY. THIS FRONT
IS ASSOCIATED WITH THE BRITISH COLUMBIA SHORTWAVE AS IT DIGS
SOUTHEAST INTO CENTRAL MN...THEN EJECTS NORTHEAST OVER DULUTH.
THUS...THE AREA ISNT DIRECTLY HIT BY THE MID-UPPER TROPOSPHERIC
FORCING...WHICH FAVORS BETTER CONVECTION TO EJECT NORTHEAST...BUT
BROAD ASCENT FROM LARGE SCALE FORCING IS OVER THE AREA. THE CAPE
AXIS IS VERY NARROW...RIGHT ALONG THE FRONT...WITH A STOUT CAP OUT
AHEAD SUGGESTED. MUCAPE HAS REMARKABLE DROP SUGGESTED IN THE
MODEL GUIDANCE FROM 7PM TO 1 AM...ABOUT 2500 IN PEAK HEATING WEST
OF THE FORECAST AREA...TO ABOUT 750 J/KG BY 1 AM ON THE MISS
RIVER. THE WESTERN FORECAST AREAS OF NERN IA AND SERN MN HAVE THE
MOST POTENTIAL FOR SEVERE STORMS FOR A SMALL WINDOW SATURDAY
EVENING AS THE STORMS WEAKEN HEADING EAST. SPC DAY 2 RISK HAS
SHIFTED THE SLIGHT RISK EAST INTO THAT AREA...BUT NOT TOO MUCH HAS
CHANGED. MODEST 0-3KM WIND SHEAR WOULD FAVOR LINE SEGMENTS
PROMOTING DAMAGING WINDS. THE 0-3KM SHEAR VECTOR IS ALIGNED
PERPENDICULAR TO THE FRONT OR CONVECTIVE LINE...PROMOTING BETTER
COLD POOL MAINTENANCE.
SEVERE THREAT DEPENDS ON TIMING OF THE FRONT AND STORMS. ARRIVAL
IN THE EARLY EVENING WOULD FAVOR HIGHER SEVERE STORM CHANCES PER
HIGHER CAPE IN MODEST LOW-LEVEL SHEAR. CONSENSUS MODEL GUIDANCE IS
A MID-LATER EVENING APPROACH OF STORMS IN NERN IA AND SERN MN
WITH STORMS JUST PAST PEAK AND INTO WEAKENING STAGE...WITH COLD
POOLS THAT COULD PROBABLY PRODUCE ISOLATED WIND DAMAGE. WILL TAKE
A SLIGHT STEP UP IN MESSAGING MOVING TO STRONG TO ISOLATED SEVERE
STORMS.
A COOL FIRST HALF OF THE WEEK IN NORTHWEST FLOW WITH DRIER
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1242 PM CDT FRI AUG 21 2015
MAIN TAF CONCERNS ARE WINDY CONDITIONS AT BOTH TAF SITES THROUGH TAF
PERIOD. LATEST METARS INDICATE SOUTH TO SOUTHWEST WINDS HAVE
INCREASED TO 15 KNOTS WITH GUST OF 20 TO 28 KNOTS ACROSS THE AREA.
DUE TO FULL SUN THIS AFTERNOON...WINDS WILL MIX DOWN FROM ALOFT AND
CONTINUE TO BE SUSTAINED AT 15 TO 17 KNOTS WITH GUSTS 25 TO 30 KNOTS
AT BOTH RST/LSE TAF SITES. WINDS WILL SLACK OFF A BIT AFTER 00Z WITH
SUNSET. HOWEVER...SUSTAINED WINDS ARE EXPECTED TO BE AROUND 15 KNOTS
THROUGH THE NIGHT TIME HOURS. PRESSURE GRADIENT TIGHTENS AHEAD OF AN
APPROACHING COLD FRONT SATURDAY AND EXPECT WINDS TO INCREASE AFTER
12Z AT BOTH RST/LSE TAF SITES. SUSTAINED WINDS OF 15 KNOTS WILL
PREVAIL AND GUSTS 25 TO 30 KNOTS...AND POTENTIALLY GUST TO AROUND
35 KNOTS AT RST TAF SITE LATE IN THE TAF PERIOD. VFR CONDITIONS
WILL PREVAIL THROUGH THE TAF PERIODS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
655 AM CDT FRI AUG 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT FRI AUG 21 2015
MOST OF THE FORECAST TIME THIS MORNING WAS ENSURING WE WERE ON TRACK
WITH RAIN CHANCES IN THE RETURN FLOW TODAY....CLOUDS ON
SATURDAY...BUT MAINLY THE SATURDAY NIGHT THUNDERSTORM THREATS AND
ANY MESSAGING THAT WILL BE NEEDED FOR THOSE OUTDOORS.
CURRENT OBSERVATIONAL DATA AS OF 21.07Z INDICATES NW-SE ORIENTED
CLOUD BANDING AROUND 10KFT ACROSS CENTRAL MN ASSOCIATED WITH
FRONTOGENESIS IN THE 800-900 MB LAYER PER LATEST RAP ANALYSIS.
TSRA AND LIGHTNING IN NWRN IA ON THE NOSE OF THE LOW-LEVEL JET PER
88D VWPS AND RAP ANALYSIS. SPC MESOANALYSIS SHOWING THAT TSRA IS
ON THE NORTHERN EXTENT OF THE MUCAPE REGION /ONLY ABOUT 250 J/KG
THERE/.
GOES FOG PRODUCT AND SURFACE OBSERVATIONS SHOW A LOWER CLOUD FIELD
OVER OK/TX SOUTH IN A RICH MOIST POOL OF SURFACE DEWPOINTS OVER
65F...AND 925MB DEWPOINTS AT 18C PER 21.00Z RAOBS. WILL HAVE TO
WATCH THIS AREA AS IT ADVECTS NORTHWARD AHEAD OF THE FRONT THAT IS
MOVING IN FOR SATURDAY NIGHT...ASSOCIATED WITH THE SHORTWAVE
TROUGH NOW WORKING SOUTHWARD THROUGH BRITISH COLUMBIA /PER GOES
WATER VAPOR/. RAP ANALYSIS INDICATES THIS SPINNER HAS A TROPOPAUSE
FOLD DOWN TO ROUGHLY 750 MB...SO A POTENT VORTEX.
SHORT TERM GUIDANCE SUPPORTS EVOLVING THE FRONTOGENESIS AND THE
LOW-LEVEL JET NOSE CONVERGENCE NORTHEAST THROUGH THE FIRST PORTION
OF TODAY INTO NRN WI BY AFTERNOON. THERE WILL LIKELY BE VERY LIGHT
RADAR RETURNS AND PER 00Z RAOB DATA...SOME PRETTY DRY AIR TO
OVERCOME BELOW THE ACCAS CLOUD BASE /10KFT/. FOR NOW...HAVE KEPT
THE HIGHER PROBABILITY DRY FORECAST. SPRINKLES OR AN ISOLATED
WETTING SHOWER MAY BE POSSIBLE WITH FORCING EVOLUTION NEWRD.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT FRI AUG 21 2015
NO BIG CHANGES DURING THIS PERIOD.
SOUTHWESTERLY FLOW WILL PREVAIL SATURDAY AND PRE-FRONTALLY WILL
NEED TO WATCH THE SURGE OF 925 MB MOISTURE NORTHWARD TONIGHT.
CONSENSUS 21.00Z GUIDANCE SUGGESTS THIS TONGUE REMAINS WEST OF THE
AREA UNTIL FRONT ARRIVES SAT EVENING. HAVE INCREASED WIND GUSTS
SATURDAY WITH STRONGER LOW-LEVEL WIND FIELD SUGGESTED AND MIXING
DEPTH INTO THE 35-38KT CONSENSUS 900MB WINDS.
TIMING IS ABOUT THE SAME AS PREVIOUS FORECASTS FOR FRONT TO
BECOME ACTIVE TO THE WEST OF THE AREA LATER SATURDAY. THIS FRONT
IS ASSOCIATED WITH THE BRITISH COLUMBIA SHORTWAVE AS IT DIGS
SOUTHEAST INTO CENTRAL MN...THEN EJECTS NORTHEAST OVER DULUTH.
THUS...THE AREA ISNT DIRECTLY HIT BY THE MID-UPPER TROPOSPHERIC
FORCING...WHICH FAVORS BETTER CONVECTION TO EJECT NORTHEAST...BUT
BROAD ASCENT FROM LARGE SCALE FORCING IS OVER THE AREA. THE CAPE
AXIS IS VERY NARROW...RIGHT ALONG THE FRONT...WITH A STOUT CAP OUT
AHEAD SUGGESTED. MUCAPE HAS REMARKABLE DROP SUGGESTED IN THE
MODEL GUIDANCE FROM 7PM TO 1 AM...ABOUT 2500 IN PEAK HEATING WEST
OF THE FORECAST AREA...TO ABOUT 750 J/KG BY 1 AM ON THE MISS
RIVER. THE WESTERN FORECAST AREAS OF NERN IA AND SERN MN HAVE THE
MOST POTENTIAL FOR SEVERE STORMS FOR A SMALL WINDOW SATURDAY
EVENING AS THE STORMS WEAKEN HEADING EAST. SPC DAY 2 RISK HAS
SHIFTED THE SLIGHT RISK EAST INTO THAT AREA...BUT NOT TOO MUCH HAS
CHANGED. MODEST 0-3KM WIND SHEAR WOULD FAVOR LINE SEGMENTS
PROMOTING DAMAGING WINDS. THE 0-3KM SHEAR VECTOR IS ALIGNED
PERPENDICULAR TO THE FRONT OR CONVECTIVE LINE...PROMOTING BETTER
COLD POOL MAINTENANCE.
SEVERE THREAT DEPENDS ON TIMING OF THE FRONT AND STORMS. ARRIVAL
IN THE EARLY EVENING WOULD FAVOR HIGHER SEVERE STORM CHANCES PER
HIGHER CAPE IN MODEST LOW-LEVEL SHEAR. CONSENSUS MODEL GUIDANCE IS
A MID-LATER EVENING APPROACH OF STORMS IN NERN IA AND SERN MN
WITH STORMS JUST PAST PEAK AND INTO WEAKENING STAGE...WITH COLD
POOLS THAT COULD PROBABLY PRODUCE ISOLATED WIND DAMAGE. WILL TAKE
A SLIGHT STEP UP IN MESSAGING MOVING TO STRONG TO ISOLATED SEVERE
STORMS.
A COOL FIRST HALF OF THE WEEK IN NORTHWEST FLOW WITH DRIER
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 650 AM CDT FRI AUG 21 2015
WARM AIR ADVECTION AND SOME MOISTURE TRANSPORT WILL CONTINUE TO
PRODUCE A SCATTERED TO BROKEN MID DECK OF CLOUDS ACROSS THE AREA
TODAY...AND THEN SKIES WILL CLEAR. WITH DIURNAL MIXING TODAY...
THE SUSTAINED SOUTH WINDS WILL CLIMB INTO THE 10 TO 20 KNOTS...
AND THE WINDS WILL GUST INTO THE 20 TO 30 KNOT RANGE. THE WINDS
WILL THEN SUBSIDE QUICKLY THIS EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
318 AM CDT FRI AUG 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 318 AM CDT FRI AUG 21 2015
MOST OF THE FORECAST TIME THIS MORNING WAS ENSURING WE WERE ON TRACK
WITH RAIN CHANCES IN THE RETURN FLOW TODAY....CLOUDS ON
SATURDAY...BUT MAINLY THE SATURDAY NIGHT THUNDERSTORM THREATS AND
ANY MESSAGING THAT WILL BE NEEDED FOR THOSE OUTDOORS.
CURRENT OBSERVATIONAL DATA AS OF 21.07Z INDICATES NW-SE ORIENTED
CLOUD BANDING AROUND 10KFT ACROSS CENTRAL MN ASSOCIATED WITH
FRONTOGENESIS IN THE 800-900 MB LAYER PER LATEST RAP ANALYSIS.
TSRA AND LIGHTNING IN NWRN IA ON THE NOSE OF THE LOW-LEVEL JET PER
88D VWPS AND RAP ANALYSIS. SPC MESOANALYSIS SHOWING THAT TSRA IS
ON THE NORTHERN EXTENT OF THE MUCAPE REGION /ONLY ABOUT 250 J/KG
THERE/.
GOES FOG PRODUCT AND SURFACE OBSERVATIONS SHOW A LOWER CLOUD FIELD
OVER OK/TX SOUTH IN A RICH MOIST POOL OF SURFACE DEWPOINTS OVER
65F...AND 925MB DEWPOINTS AT 18C PER 21.00Z RAOBS. WILL HAVE TO
WATCH THIS AREA AS IT ADVECTS NORTHWARD AHEAD OF THE FRONT THAT IS
MOVING IN FOR SATURDAY NIGHT...ASSOCIATED WITH THE SHORTWAVE
TROUGH NOW WORKING SOUTHWARD THROUGH BRITISH COLUMBIA /PER GOES
WATER VAPOR/. RAP ANALYSIS INDICATES THIS SPINNER HAS A TROPOPAUSE
FOLD DOWN TO ROUGHLY 750 MB...SO A POTENT VORTEX.
SHORT TERM GUIDANCE SUPPORTS EVOLVING THE FRONTOGENESIS AND THE
LOW-LEVEL JET NOSE CONVERGENCE NORTHEAST THROUGH THE FIRST PORTION
OF TODAY INTO NRN WI BY AFTERNOON. THERE WILL LIKELY BE VERY LIGHT
RADAR RETURNS AND PER 00Z RAOB DATA...SOME PRETTY DRY AIR TO
OVERCOME BELOW THE ACCAS CLOUD BASE /10KFT/. FOR NOW...HAVE KEPT
THE HIGHER PROBABILITY DRY FORECAST. SPRINKLES OR AN ISOLATED
WETTING SHOWER MAY BE POSSIBLE WITH FORCING EVOLUTION NEWRD.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 318 AM CDT FRI AUG 21 2015
NO BIG CHANGES DURING THIS PERIOD.
SOUTHWESTERLY FLOW WILL PREVAIL SATURDAY AND PRE-FRONTALLY WILL
NEED TO WATCH THE SURGE OF 925 MB MOISTURE NORTHWARD TONIGHT.
CONSENSUS 21.00Z GUIDANCE SUGGESTS THIS TONGUE REMAINS WEST OF THE
AREA UNTIL FRONT ARRIVES SAT EVENING. HAVE INCREASED WIND GUSTS
SATURDAY WITH STRONGER LOW-LEVEL WIND FIELD SUGGESTED AND MIXING
DEPTH INTO THE 35-38KT CONSENSUS 900MB WINDS.
TIMING IS ABOUT THE SAME AS PREVIOUS FORECASTS FOR FRONT TO
BECOME ACTIVE TO THE WEST OF THE AREA LATER SATURDAY. THIS FRONT
IS ASSOCIATED WITH THE BRITISH COLUMBIA SHORTWAVE AS IT DIGS
SOUTHEAST INTO CENTRAL MN...THEN EJECTS NORTHEAST OVER DULUTH.
THUS...THE AREA ISNT DIRECTLY HIT BY THE MID-UPPER TROPOSPHERIC
FORCING...WHICH FAVORS BETTER CONVECTION TO EJECT NORTHEAST...BUT
BROAD ASCENT FROM LARGE SCALE FORCING IS OVER THE AREA. THE CAPE
AXIS IS VERY NARROW...RIGHT ALONG THE FRONT...WITH A STOUT CAP OUT
AHEAD SUGGESTED. MUCAPE HAS REMARKABLE DROP SUGGESTED IN THE
MODEL GUIDANCE FROM 7PM TO 1 AM...ABOUT 2500 IN PEAK HEATING WEST
OF THE FORECAST AREA...TO ABOUT 750 J/KG BY 1 AM ON THE MISS
RIVER. THE WESTERN FORECAST AREAS OF NERN IA AND SERN MN HAVE THE
MOST POTENTIAL FOR SEVERE STORMS FOR A SMALL WINDOW SATURDAY
EVENING AS THE STORMS WEAKEN HEADING EAST. SPC DAY 2 RISK HAS
SHIFTED THE SLIGHT RISK EAST INTO THAT AREA...BUT NOT TOO MUCH HAS
CHANGED. MODEST 0-3KM WIND SHEAR WOULD FAVOR LINE SEGMENTS
PROMOTING DAMAGING WINDS. THE 0-3KM SHEAR VECTOR IS ALIGNED
PERPENDICULAR TO THE FRONT OR CONVECTIVE LINE...PROMOTING BETTER
COLD POOL MAINTENANCE.
SEVERE THREAT DEPENDS ON TIMING OF THE FRONT AND STORMS. ARRIVAL
IN THE EARLY EVENING WOULD FAVOR HIGHER SEVERE STORM CHANCES PER
HIGHER CAPE IN MODEST LOW-LEVEL SHEAR. CONSENSUS MODEL GUIDANCE IS
A MID-LATER EVENING APPROACH OF STORMS IN NERN IA AND SERN MN
WITH STORMS JUST PAST PEAK AND INTO WEAKENING STAGE...WITH COLD
POOLS THAT COULD PROBABLY PRODUCE ISOLATED WIND DAMAGE. WILL TAKE
A SLIGHT STEP UP IN MESSAGING MOVING TO STRONG TO ISOLATED SEVERE
STORMS.
A COOL FIRST HALF OF THE WEEK IN NORTHWEST FLOW WITH DRIER
CONDITIONS AND BELOW NORMAL TEMPERATURES...WARMING LATE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1128 PM CDT THU AUG 20 2015
VFR CONDITIONS EXPECTED.
AS SURFACE RIDGE QUICKLY PASSES TONIGHT...ALREADY SEEING RESPONSE OF
APPROACHING SHORT WAVE TROUGH COMING THROUGH CENTRAL PLAINS. LOW
LEVEL JET ACROSS WESTERN IOWA INTO MINNESOTA IS HELPING WITH
FRONTOGENETIC BAND SETTING UP IN THE FORM OF MID LEVEL CLOUDS THAT
HAVE FORMED ACROSS MINNESOTA LAST FEW HOURS. LOW LEVEL MOISTURE
TRANSPORT HAS ALSO LED TO SOME CLOUDS AND ISOLATED SHOWERS FURTHER
WEST. GIVEN SUCH DRY AIRMASS AND ONLY MODEST LIFT WITH WAVE...
WILL NOT INTRODUCE ANY RAIN.
THIS FOCUS AREA SHIFTS EAST OF THE AREA AFTER DAYBREAK FRIDAY...SO
OUTSIDE OF A FEW DAYTIME CUMULUS CLOUDS THAT COULD FORM...LOOKING AT
A TRANQUIL AVIATION PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...SHEA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1108 PM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 856 PM CDT SAT AUG 22 2015
THE BAND OF SHOWERS AND ISOLATED STORMS ACROSS EAST CENTRAL IL HAS
DISSIPATED, WHILE A FEW SHOWERS LINGER CLOSER TO THE CENTER OF THE
SHORTWAVE SOUTH OF HIGHWAY 50. THE MAIN CONCERN THE REST OF THE
NIGHT WILL SHIFT TO THE APPROACHING COLD FRONT, THAT IS PROJECTED
TO REACH OUR WESTERN COUNTIES LATER TONIGHT. THE LATEST HRRR AND
RAP GUIDANCE SHOW A DIMINISHING TREND IN THE LINE OF STORMS AS
THEY MOVE ACROSS ILLINOIS. THE TIMING OF THE FRONTS ARRIVAL LENDS
CREDENCE TO THAT TREND, WITH LOW INSTABILITY AND WEAKENING SHEAR
PROFILES EARLY SUNDAY MORNING. WE WILL KEEP THE PROGRESSION OF A
BAND OF CHANCE POPS ACROSS OUR COUNTIES FROM WEST TO EAST LATE
TONIGHT AND SUNDAY MORNING. CONFIDENCE IS LOWERING IN A SOLID
LINE OF SHOWERS/STORMS, WITH A MORE BROKEN LINE LOOKING MORE
LIKELY.
THE DIURNAL SWING TONIGHT WILL BE TEMPERED BY INCREASING CLOUD
COVER AHEAD OF THE STORMS, AND FROM CLOUDS ASSOCIATED WITH THE
SHORTWAVE IN SOUTHERN IL. WILL KEEP LOWS IN THE MID-UPPER 60S, AS
DEWPOINTS BEGIN TO CLIMB THROUGH THE 60S.
MAIN UPDATE TONIGHT WAS TO THE WEATHER GRIDS THIS EVENING, AND TO
INCREASE CLOUD COVER TONIGHT. OTHERWISE, THE FORECAST GRIDS LOOK
REASONABLE FOR NOW.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT SAT AUG 22 2015
A WEAKENING AREA OF SHOWERS AND ISOLATED THUNDERSTORMS SOUTHWEST OF
EFFINGHAM WERE AHEAD OF A SHORT WAVE TROF OVER CENTRAL MO/AR. THIS
CONVECTION WILL CONTINUE TO WEAKEN AS IT TRACKS ENE INTO SOUTHEAST
IL DURING REST OF THIS AFTERNOON AND EARLY EVENING BEFORE SUNSET.
HIGHEST POPS WERE OVER SHELBY...EFFINGHAM AND CLAY COUNTIES. MOST OF
CENTRAL IL SHOULD STAY DRY THROUGH THIS EVENING WITH PARTLY TO
MOSTLY CLOUDY SKIES. A 997 MB LOW PRESSURE OVER EAST CENTRAL ND HAS
A COLD FRONT EXTENDING INTO EASTERN SD/NEBRASKA AND NW KS. MODELS
TAKE COLD FRONT EAST TOWARD THE IA/IL BORDER AND CENTRAL MO BY 12Z/7
AM SUNDAY. CHANCES OF SHOWERS AND THUNDERSTORMS INCREASE OVER IL
RIVER VALLEY AFTER 06Z/1 AM TONIGHT AND REACH AS FAR EAST AS I-57 BY
12Z/SUNDAY WITH SLIGHT POPS IN EASTERN IL LATE TONIGHT. SPC KEEPS
MARGINAL RISK OF SEVERE STORMS WEST OF CWA (FROM QUAD CITIES TO
QUINCY WEST) TONIGHT. NUDGED LOWS UP A TAD OVERNIGHT INTO THE MID TO
UPPER 60S DUE TO MORE CLOUD COVER AND SE WINDS. COOLEST LOWS IN THE
LOWER 60S AROUND DANVILLE WHERE MET/MAV HAVE 62F.
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 256 PM CDT SAT AUG 22 2015
THERE WILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS TO START THE DAY
SUNDAY ACROSS CENTRAL AND SOUTHEAST ILLINOIS AS A COLD FRONT BEGINS
TO PUSH INTO THE AREA FROM THE NORTHWEST. THE EARLY ARRIVAL OF THE
FRONT, WHICH SHOULD EXIT THE FORECAST AREA INTO INDIANA DURING THE
AFTERNOON EVEN IN THE SLOWER MODEL SOLUTIONS, WILL PRECLUDE
SIGNIFICANT PRE FRONTAL INSTABILITY. GUIDANCE STILL SUGGESTS CAPE
VALUES REACHING AROUND 2500 J/KG IN THE FAR EAST/SOUTHEAST PORTION
OF THE FORECAST AREA, BUT CORRESPONDING BULK SHEAR VALUES ARE STILL
RATHER WEAK AND TOP OUT AROUND 25 KTS. SO, DO NOT EXPECT MORE THAN
SCATTERED SHOWERS/STORMS ACROSS THE FORECAST AREA AHEAD OF THE
FRONT, WITH PRECIPITATION QUICKLY ENDING FROM WEST TO EAST DURING
THE AFTERNOON AS THE FRONT SWEEPS THROUGH.
THE UPPER LEVEL FLOW ACROSS THE AREA TRENDS NORTHWESTERLY BEHIND
SUNDAY`S SYSTEM, ALBEIT MOSTLY NEUTRAL LOCALLY, AS UPPER RIDGING
BUILDS THROUGH THE ROCKIES. THIS UPPER FLOW PATTERN IS ACCOMPANIED
BY HIGH PRESSURE AT THE SURFACE MORE OFTEN THAN NOT, AND THESE
FEATURES SHOULD HELP KEEP CONDITIONS QUIET AND SLIGHTLY COOLER THAN
NORMAL. MODEL GUIDANCE NOT IN VERY GOOD AGREEMENT IN WHEN THE NEXT
DISTURBANCE OF CONSEQUENCE WILL IMPACT THE AREA IN THIS FLOW REGIME,
BUT IT DOES NOT APPEAR AS THOUGH IT WILL ARRIVE MUCH SOONER THAN
NEXT SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1107 PM CDT SAT AUG 22 2015
A FEW SHOWERS PERSISTED EAST OF CMI LATE THIS EVENING, WITH DRY
CONDITIONS EVERYWHERE ELSE ACROSS THE FORECAST AREA THE LAST
COUPLE OF HOURS. THAT ACTIVITY SHOULD DISSIPATE AS IT MOVES INTO
INDIANA.
CLOUD HEIGHTS DIPPED TO MVFR AT BMI...WITH VFR LEVELS AT ALL
OTHER TERMINAL SITES. UPSTREAM TRENDS SHOW VFR CONDITIONS SHOULD
RETURN FOR SEVERAL HOURS BEFORE THE RAIN REACHES NEAR PIA TO SPI.
THEN CLOUD HEIGHTS COULD DIP BACK TO MVFR AS THE LINE OF SHOWERS
AND STORMS MOVE ACROSS THE AREA. AS THE COLD FRONT MOVES ACROSS
ILLINOIS, A LINE OF SHOWERS/STORMS WILL AFFECT THE TERMINAL SITES
WITHIN A GENERAL WINDOW OF 3-5 HOURS. NO SEVERE WEATHER IS
EXPECTED, AS SHEAR VALUES REMAIN LOW, AND INSTABILITY MARGINAL.
THE SPEED OF THE FRONT SHOULD PUT MOST OF THE PRECIP EAST OF THE
TERMINAL SITES BEFORE PEAK AFTERNOON HEATING, ALSO REDUCING THE
CHANCES OF PARTICULARLY STRONG STORMS NEAR THE TAF LOCATIONS.
FORECAST SOUNDINGS SUPPORT RAPID CLEARING DEVELOPING SUNDAY
AFTERNOON FROM WEST TO EAST, REACHING CMI BY 21Z.
WINDS WILL START OUT SOUTHEAST AT LESS THAN 10KT, THEN BECOME
SOUTH AHEAD OF THE LINE OF PRECIP. ONCE THE COLD FRONT PASSES
SUNDAY MORNING, WINDS WILL BECOME W-NW AND INCREASE TO 10-15KT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHIMON
SHORT TERM...07
LONG TERM...BAK
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
344 AM EDT SUN AUG 23 2015
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW
&&
.SYNOPSIS...
ISSUED AT 344 AM EDT SUN AUG 23 2015
SCATTERED THUNDERSTORMS WILL ACCOMPANY A STRONG COLD
FRONT LATER TODAY. THE FRONT WILL SHIFT EAST QUICKLY THIS
EVENING...WITH HIGH PRESSURE REESTABLISHING OVER THE OHIO VALLEY.
DRY AND PLEASANT WEATHER IS EXPECTED FOR THE ENTIRE WEEK AS THE HIGH
REMAINS THE DOMINANT WEATHER FEATURE.
&&
.NEAR TERM /TODAY/...
ISSUED AT 344 AM EDT SUN AUG 23 2015
ISOLATED SHOWERS HAVE DEVELOPED ACROSS THE WESTERN HALF OF THE
FORECAST AREA EARLY THIS MORNING AS A WEAK UPPER WAVE MOVES ACROSS
THE REGION. THE INCREASED CLOUD COVER ASSOCIATED WITH THE WAVE ALOFT
WAS KEEPING TEMPS WARMER THIS MORNING. 07Z TEMPS WERE LARGELY IN THE
60S.
THE INITIAL UPPER WAVE ACROSS THE AREA WILL SHIFT EAST PRIOR TO
DAYBREAK. COULD SEE ISOLATED SHOWERS OVER THE NEXT 2-3 HOURS BEFORE
AXIS OF DRIER AIR IMMEDIATELY BEHIND THE WAVE NOTED OFF WATER VAPOR
IMAGERY MOVES IN FROM THE WEST. SHOULD ALSO SEE A DECREASE IN CLOUDS
TOWARDS DAYBREAK WITH THE ARRIVAL OF THE DRIER AIR AS WELL.
THE FOCUS THEN TURNS TO THE APPROACH OF A COLD FRONT FROM THE WEST
LATER TODAY. CONVECTION ALONG THE BOUNDARY IS STEADILY WEAKENING
EARLY THIS MORNING OVER IOWA AND NORTHERN MISSOURI AND SHOULD
CONTINUE TO DO SO THROUGH SUNRISE AS THE STORMS MOVE INTO A LESS
FAVORABLE AIRMASS. MID AND HIGH LEVEL REMNANT CLOUD DEBRIS FROM
STORMS OVER THE MID MISSISSIPPI VALLEY WILL DRIFT INTO THE REGION
AFTER DAYBREAK...BUT EXPECT MOST AREAS WILL REMAIN DRY THROUGH
MIDDAY.
SCATTERED CONVECTION WILL REFIRE ALONG THE FRONT AS IT MOVES THROUGH
THE FORECAST AREA DURING THE AFTERNOON. THIN AXIS OF DEEPER MOISTURE
WITH PRECIP WATER VALUES AROUND 1.50 INCHES WILL ADVECT INTO THE
REGION IMMEDIATELY AHEAD OF THE BOUNDARY. THE DEEPER MOISTURE WILL
COMBINE WITH PEAK MLCAPE VALUES AT 1000-1500 J/KG...LOW LEVEL
CONVERGENCE AND BL SHEAR VALUES BRIEFLY PEAKING NEAR 30KTS AS THE
PRIMARY CATALYSTS IN CONVECTIVE DEVELOPMENT DURING THE AFTERNOON.
THERE ARE MITIGATING FACTORS IN PLAY THOUGH HOWEVER. DESPITE
DIFFLUENCE ALOFT...STRONGER UPPER FORCING WILL REMAIN DISPLACED TO
THE NORTH OF THE AREA IN CLOSER PROXIMITY TO THE UPPER LOW. MODEL
SOUNDINGS FROM BOTH THE OP GFS AND THE RAP HINT AT A WEAK CAPPING
INVERSION PRESENT NEAR 10KFT WITH LARGELY POOR LAPSE RATES WHICH
WOULD LIMIT AVAILABLE INSTABILITY AND CONVECTIVE COVERAGE. NAM MODEL
SOUNDINGS PRESENT LITTLE IN THE WAY OF CAPPING AND CONSEQUENTLY
GREATER AVAILABLE INSTABILITY DURING THE AFTERNOON...BUT THIS
SOLUTION IS NOT PREFERRED AS CLOSER ANALYSIS INDICATES THAT IT IS
LIKELY OVERDOING BOTH SURFACE TEMPS AND DEWPOINTS LATER TODAY.
TAKING ALL OF THIS INTO ACCOUNT...HAVE TRENDED TOWARDS A CONSENSUS
SOLUTION LED BY THE HI RES SUITE OF THE HRRR...RAP AND WRF WHICH
BRING A NARROW YET BROKEN CONVECTIVE LINE QUICKLY ACROSS THE
FORECAST AREA PRIMARILY BETWEEN 18Z AND 00Z. HIGHEST POPS WILL BE
EMPLOYED OVER THE NORTHEAST HALF OF THE FORECAST AREA WHERE
INSTABILITY WILL BE GREATEST AND INTERACT WITH BEST SHEAR AND
MOISTURE. STORMS ARE LIKELY TO DISRUPT OUTDOOR ACTIVITIES
BRIEFLY...WITH GUSTY WINDS AND LIGHTNING...AND POSSIBLY HAIL.
STRONGER CELLS WILL HAVE THE POTENTIAL FOR AN ISOLATED SEVERE RISK
WITH DAMAGING WINDS AND LARGE HAIL...ESPECIALLY NORTH AND EAST OF
THE INDY METRO. STORMS WILL END RAPIDLY WITH THE FRONTAL PASSAGE BY
EARLY EVENING.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE FOR HIGHS CONSIDERING
INCREASING CLOUDS AND STORMS FOR THE AFTERNOON. EXPECTING GENERALLY
LOW TO MID 80S.
&&
.SHORT TERM /|TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 344 AM EDT SUN AUG 23 2015
FORECAST CHALLENGES ARE MINOR THROUGH THE SHORT TERM...AS STRONG
HIGH PRESSURE BUILDS IN WITH DRY...PLEASANT WEATHER THROUGH MIDWEEK.
HELD ONTO A LOW CHANCE POPS OVER FAR EASTERN COUNTIES FOR A FEW
HOURS THIS EVENING TO ACCOUNT FOR ANY LINGERING CONVECTION AS THE
COLD FRONT SWEEPS OFF TO THE EAST. EXPECT THE ENTIRE FORECAST AREA
WILL BE DRY BY 02-03Z AT THE LATEST.
STRONG UPPER LOW BY LATE AUGUST STANDARDS WILL PINWHEEL SLOWLY
THROUGH THE GREAT LAKES...MAINTAINING A BROAD TROUGH WITH COOL
CYCLONIC FLOW OVER THE REGION THROUGH MIDWEEK. EXPECT PLENTY OF
SUNSHINE BOTH MONDAY AND TUESDAY WITH DIURNAL AFTERNOON CU IN THE
COLD ADVECTION REGIME. CU WILL DISSIPATE NEAR SUNSET BOTH
DAYS...SETTING THE STAGE FOR MAINLY CLEAR SKIES AT NIGHT WITH COOL
TEMPERATURES. ALL IN ALL...A VERY PLEASANT STRETCH OF WEATHER
UPCOMING FOR MUCH OF THIS WEEK.
TEMPS...UTILIZED A MOS BLEND FOR HIGHS MONDAY...THEN TRENDED TOWARDS
WARMER MAVMOS GUIDANCE FOR TUESDAY. HIGHS WILL RUN ABOUT 5-10
DEGREES BELOW NORMAL BOTH DAYS IN THE 70S. SHOULD SEE A NICE RURAL-
URBAN SPLIT IN OVERNIGHT TEMPS WITH POTENTIAL FOR NORMAL COOL SPOTS
ACROSS THE FORECAST AREA TO FALL INTO THE 40S...ESPECIALLY
EARLY TUESDAY MORNING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 223 AM EDT SUN AUG 23 2015
GUIDANCE CONTINUES TO DEPICT A DRY AND COOL EXTENDED PORTION OF THE
FORECAST...ALTHOUGH WITH SOME MODERATION OF TEMPERATURES BACK TOWARD
NORMAL NEAR THE END OF THE PERIOD.
MODELS NOW SHOW A STRONGER SURFACE RIDGE ACROSS THE AREA LATE IN THE
WEEK...WHICH WOULD PREVENT FRONTAL ZONE FROM MAKING IT INTO THE AREA
UNTIL AFTER THE SEVEN DAY FORECAST PERIOD. CAN GO WITH A DRY
FORECAST THROUGHOUT THE EXTENDED.
BLENDED INITIALIZATION HANDLED THIS WELL AND ONLY MINOR TWEAKS WERE
REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 23/06Z TAFS/...
ISSUED AT 1230 AM EDT SUN AUG 23 2015
SOME SCATTERED CLOUD COVER AROUND 050 EXPECTED OVERNIGHT...WITH
LAYERED CLOUD ABOVE THAT LEVEL. LIFT...MOISTURE ADVECTION...AND
HEATING AFTER SUNRISE ON SUNDAY SHOULD ALLOW FOR THE DEVELOPMENT OF
CEILINGS IN THE 030-050 RANGE BY MID TO LATE MORNING SUNDAY.
POTENTIAL EXISTS FOR SCATTERED CONVECTION TOWARDS/AFTER 231800Z AS A
COLD FRONT APPROACHES THE AREA.
LIGHT SURFACE WINDS OVERNIGHT WILL BECOME 200-230 DEGREES AT 8-12
KTS BY MIDDAY SUNDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM...NIELD
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
137 AM EDT SUN AUG 23 2015
.SYNOPSIS...
ISSUED AT 331 PM EDT SAT AUG 22 2015
DRY CONDITIONS WILL PREVAIL INTO EARLY SUNDAY AS HIGH PRESSURE
MOVES EAST OF THE REGION. SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO ACCOMPANY A COLD FRONT AS IT SWEEPS ACROSS THE AREA
SUNDAY AFTERNOON INTO EARLY SUNDAY EVENING...WITH COOLER AND
DRIER AIR FILTERING BACK INTO THE REGION EARLY NEXT WEEK. LOWS
TONIGHT WILL DROP INTO THE MID 50S TO LOW 60S...WITH HIGHS ON
SUNDAY RANGING BETWEEN THE UPPER 70S AND LOW 80S.
&&
.UPDATE...
ISSUED AT 127 AM EDT SUN AUG 23 2015
REMNANTS OF MID LEVEL WAVE IN MISSOURI WAS PUSHING THROUGH THE
AREA WITH A FEW SHOWERS NOW MOVING INTO FAR SW COUNTIES. DRY
AIRMASS IS LIKELY LIMITING HOW MUCH IS REACHING THE GROUND...BUT
STILL APPEARS ENOUGH TO WARRANT THROWING IN SOME 15 TO 20 POPS FOR
A FEW HOURS. HRRR SEEMS TO HANDLE THIS FAIRLY WELL AND TRACKS IT
EAST WITH A WEAKENING TREND SO WILL FOLLOW ITS LEAD BUT WATCH FOR
CHANGES IN TRENDS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 331 PM EDT SAT AUG 22 2015
A SMALLER SCALE/CONVECTIVELY AIDED MID LEVEL TROUGH ACROSS
MISSOURI WILL DAMPEN EASTWARD THROUGH THE OHIO VALLEY TONIGHT.
DEEPER MOISTURE/PRECIP CHANCES WITH THIS FEATURE WILL REMAIN WELL
SSW OF THE LOCAL AREA WITH ONLY A GRADUAL INCREASE IN MID-HIGH
LEVEL CLOUDS ANTICIPATED AS WEAK WAA ENSUES ON BACKSIDE OF EXITING
SFC HIGH.
A VIGOROUS/DEEPENING UPPER LEVEL SYSTEM JUST ENTERING THE NORTHERN
PLAINS WILL CLOSE OFF INTO FAR SOUTHWEST ONTARIO BY LATER SUNDAY-
SUNDAY NIGHT. AN UNDERCUTTING SHORTWAVE WILL TAKE ON A NEGATIVE TILT
AS IT LIFTS NE THROUGH THE WESTERN/NORTHERN LAKES DURING THIS
TIME...FORCING A RELATIVELY STRONG SFC COLD FRONT THROUGH THE AREA
SUNDAY AFTN-EARLY EVE. MORE FOCUSED DEEP LAYER FORCING WITH THE
AFOREMENTIONED WAVE WILL PASS NNW OF THE IWX CWA...THOUGH INCREASING
UPPER LEVEL DIVERGENCE AND WEAK HEIGHT FALLS/SHOT OF PV ADVECTION
EXPECTED ACROSS AT LEAST NORTHERN ZONES BY LATE MORNING-AFTN. THIS
IN TANDEM WITH FAVORABLE DIURNAL TIMING, DECENT DEPTH TO LOW LEVEL
FRONT/CONVERGENCE, AND AMPLE PRE-FRONTAL MOISTURE RETURN (850 MB
DEWPOINTS 14-15C & PWATS NEAR 1.5 INCHES WITHIN NARROW THETA-E
RIDGE) SHOULD ALLOW AT LEAST SCATTERED CONVECTION TO FIRE
CENTRAL/WESTERN ZONES IN THE AFTN...SHIFTING INTO EASTERN ZONES LATE
AFTN-EARLY EVE. ALSO RETAINED LOW CHANCE POPS ACROSS NORTHWESTERN
ZONES SUNDAY MORNING GIVEN POTENTIAL FOR WEAKENING UPSTREAM
ACTIVITY TO SURVIVE INTO MORE STABLE AIR.
THERE REMAINS A LOW RISK FOR A FEW SEVERE STORMS GIVEN EXPECTATIONS
FOR 1000-1500 J/KG OF MLCAPE AND 30-40 KTS OF EFFECTIVE SHEAR.
STRONGER FLOW LAGGING POST-FRONTAL, MEAGER MID-LEVEL LAPSE
RATES/FORCING, AND POTENTIAL FOR MORNING CLOUDS TO LIMIT SFC
HEATING SHOULD PRECLUDE A MORE WIDESPREAD EVENT.
OTHERWISE...TEMPS REMAIN SEASONABLE WITH ONLY MINOR TWEAKS MADE.
&&
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM EDT SAT AUG 22 2015
IN THE WAKE OF THE COLD FRONT SUNDAY COLD ADVECTION AND PRONOUNCED
BOUNDARY LAYER PRESSURE GRADIENT SUPPORTS STRONG W TO WNW WINDS OVER
THE FORECAST AREA...ESPECIALLY AS THE BOUNDARY LAYER MIXES OUT.
ADDITIONLLY WITH THE TROF AND ASSOCIATED SURFACE LOW SHIFTING SLOWLY
EASTWARD...EXPECT GUSTS TO INCREASE AS WELL.
LAKE MICHIGAN WATER TEMPS ARE QUITE WARM NOW AND THIS WILL BE ENOUGH
TO FAVOR SLIGHT CHANCE/ISOLD SHRA IN BERRIEN/CASS COUNTIES.
ADDITIONALLY THIS CLOUDS WILL OVERSPREAD THE REGION AS CU FIELD
FORMS IN THE COLD POOL.
WITH THE FETCH ACROSS LAKE MICHIGAN...WIND AND WAVES OVER THE NEAR
SHORE WATERS WILL PERSIST AS WELL. WHILE IT IS EARLY TO INCLUDE
MENTION OF SURF/BEACH HAZARDS...DO EXPECT TO SEE DANGEROUS SURF
CONDITIONS AND WILL NEED TO MONITOR FOR POSSIBLE BEACH HAZARD
HEADLINES.
GRADIENT RELAXES DURING THE EVENING/OVERNIGHT MONDAY INTO TUESDAY.
COOL/DRY AIR REMAINS IN PLACE THROUGH THE REST OF THE EXTENDED.
MODELS ALL HINT THAT THERE WILL BE SHORTWAVES RIPPLING THROUGHT THE
WESTERLIES AND THROUGH THE MEAN TROF OVER THE GREAT LAKES...HOWEVER
PLACEMENT/TIMING/INTENSITY ARE WAY TOO NEBULOUS TO SPECIFICALLY NAIL
DOWN ANY PRECIPITATION CHANCES. MODEL CONSENSUS SUGGESTS THAT BY
NEXT WEEKEND THERE COULD BE ANOTHER CHANCE OF SHOWERS...AND FOR
CONSISTENCY...HAVE INCLUDED SLIGHT CHANCE/CHANCE POP FOR FRIDAY
NIGHT/SATURDAY. THIS IS A VERY PESSIMISTIC FORECAST...AND IT IS
DOUBTFUL THAT THE 24 HOUR PERIOD WILL BE A WASHOUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 127 AM EDT SUN AUG 23 2015
TAF SITES SHOULD REMAIN DRY INTO MID MORNING SUNDAY BEFORE AN
APPROACHING COLD FRONT BRINGS AT LEAST A NARROW WINDOW OF SHOWERS
AND STORMS. CONVECTION WILL DEVELOP NEAR OR JUST TO THE WEST OF
KSBN AND THEN INTENSIFY AS IT MOVES EAST. MAY BE SOME THUNDER AT
KSBN BUT HIGHER CONFIDENCE AT KFWA TO WARRANT ADDING A TEMPO
GROUP. LATER AMENDMENTS WILL BE NEEDED AS EVOLUTION OF UPSTREAM
CONVECTION BECOMES CLEARER.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 7 PM EDT
TUESDAY FOR LMZ043-046.
&&
$$
UPDATE...FISHER
SYNOPSIS...STEINWEDEL
SHORT TERM...STEINWEDEL
LONG TERM...LEWIS
AVIATION...FISHER
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AREA FORECAST DISCUSSION
NWS JACKSON KY
210 AM EDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 1110 PM EDT SAT AUG 22 2015
WATER VAPOR SAT AND MOST MODELS ARE CONTINUING TO SHOW MID LEVEL
WAVE PROGRESSING EAST INTO THE REGION. THAT SAID RIGHT NOW THINK
THE GFS HAS THE BEST HANDLE ON THE SYNOPTICS THIS EVENING...THE
NAM SEEMS A BIT TOO ROBUST WITH MOISTURE OVERALL. NOW RADAR HAS
SHOWN A FEW RETURNS TO THE SW AND INTO PORTIONS OF CENTRAL
KY...BUT MUCH OF THIS IS AT MOST SPRINKLES BASED ON THE HIGH
BASES/MOSTLY ABOVE 10 KFT. THEREFORE JUST ISSUED A GNOW TO COVER
THIS GIVEN THE FACT THAT THIS ACTIVITY IS LIKELY NOT MEASURING.
THE HRRR HAS CONTINUED TO WEAKEN ANY OF THE SHOWERS ACROSS CENTRAL
KY AND MIDDLE TN...SO DID NOT ADJUST THE POPS UP MUCH GIVEN THIS
TREND. MAINLY MADE SOME ADJUSTMENTS TO TEMP/DEWS/WINDS WITH LATEST
OBS.
UPDATE ISSUED AT 727 PM EDT SAT AUG 22 2015
SYNOPTICALLY WE CONTINUE TO HAVE HIGH PRESSURE CENTERED OFF TO THE
NE NEAR THE UPPER MID ATLANTIC REGION...BUT STILL KEEPING CONTROL
OF THE OVERALL SENSIBLE WEATHER HERE IN EASTERN KY. MODELS AND WV
IMAGERY INDICATE LEAD MID LEVEL WAVE SLOWLY MOVING EAST ACROSS THE
MIDDLE MISSISSIPPI RIVER VALLEY. THIS HAS SPARKED OFF SHOWERS AND
THUNDERSTORMS IN MIDDLE TN...WEST TN...WESTERN KY THAT ARE SLOWLY
MOVING NORTH AND EAST...HOWEVER THEY ARE LOSING STEAM AS THEY MOVE
NE WITH GENERALLY DRIER AIR IN PLACE AND HIGH PRESSURE NOSING
SOUTH. OVERALL THE CAMS SEEM TO KEEP THIS TREND THIS EVENING AS
WELL...ALSO THEY DO HAVE SOME SIGNAL OVERNIGHT/EARLY MORNING
SUNDAY AND WE ALREADY HAVE SLIGHT POPS IN THE SOUTH AND SOUTHEAST
TO MATCH. THEREFORE THINK POPS THIS EVENING/OVERNIGHT ARE IN GOOD
SHAPE IN REGARDS TO PREVIOUS FORECAST AND LATEST TRENDS. JUST SOME
MINOR UPDATES TO IN TEMPS/DEWS/WINDS WITH LATEST OBS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 340 PM EDT SAT AUG 22 2015
THIS AFTERNOON...A SHORTWAVE RIDGE WAS WORKING ACROSS THE REGION
DOWNSTREAM OF A SHORTWAVE NEARING THE MID MS AND LOWER OH VALLEYS.
ANOTHER MORE POTENT SHORTWAVE MEANWHILE IS WORKING FROM THE
NORTHERN ROCKIES INTO THE DAKOTAS. AT THE SFC...A LOW PRESSURE
SYSTEM PRECEDING THE MORE POTENT SHORTWAVE WAVE CENTERED OVER THE
NE SD AND NW MN AREA. THE LEAD SHORTWAVE WILL BRING INCREASING
MID AND HIGH MOISTURE LEADING TO AN INCREASE IN MID AND HIGH
CLOUDS THROUGH THE EVENING AND INTO THE OVERNIGHT. LOW LEVEL
MOISTURE WILL ALSO INCREASE A BIT AS WELL ESPECIALLY ACROSS THE
SOUTH. AS THE SHORTWAVE PASSES LATE TONIGHT A SHOWER OR TWO MAY
CREEP NORTH INTO THE SOUTHERN TIER OF COUNTIES FROM WAYNE
NORTHEAST TOWARD LETCHER.
MUCH OF SUNDAY FEATURE SOME HEIGHT RISES AND MOSTLY DRY WEATHER
IN BETWEEN THE DEPARTING INITIAL LEAD SHORTWAVE AND THE NEXT
APPROACHING SHORTWAVE AND THE COLD FRONT AS THE UPPER LEVEL LOW
AND SFC LOW PRESSURE CENTER MOVE INTO ONTARIO. THE SYSTEM WILL
GENERALLY BE RATHER MOISTURE STARVED AND INSTABILITY WILL BE
LIMITED DUE TO THE NON OPTIMAL TIMING OF THE COLD FRONT WHILE THE
BEST FORCING WILL ALSO PASS NORTH OF THE AREA. ANY CONVECTION
FROM LATE SUNDAY INTO SUNDAY NIGHT WILL LIKELY BE MAINLY ISOLATED
TO SCATTERED SHOWERS ALTHOUGH A FEW ISOLATED RUMBLES CANNOT BE
COMPLETELY RULED OUT. QPF FROM THIS SYSTEM SHOULD ALSO BE LIGHT
AND MANY LOCATIONS SHOULD REMAIN DRY THROUGH THE ENTIRE EVENT.
TEMPERATURES WILL MODERATE A FEW DEGREES FROM LAST NIGHTS
OVERNIGHT LOWS ALTHOUGH LESS CLOUD COVER IN THE NORTH AND
NORTHEAST SHOULD LEAD TO LOWER MIN T THERE...REACHING THE UPPER
50S FOR VALLEY LOCATIONS. AHEAD OF THE FRONT...WITH A WARMER START
AND WARM AIR ADVECTION AHEAD OF THE FRONT...TEMPERATURES SHOULD BE
A COUPLE DEGREES WARMER THAN TODAY ON AVERAGE. HOWEVER...HIGHS ON
SUNDAY SHOULD STILL BE NEAR NORMAL FOR THE LATTER PART OF AUGUST.
CLOUDS AND SOME PRECIP IN THE AREA AS THE FRONT BEGINS TO WORK
ACROSS EAST KY WILL LEAD TO AN EVEN MILDER NIGHT ON SUNDAY NIGHT.
HOWEVER...A RETURN TO BELOW NORMAL TEMPERATURES IS EXPECTED DURING
THE LONG TERM PERIOD.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 246 PM EDT SAT AUG 22 2015
SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION AS A COLD FRONT
DEPARTS TO OUR EAST ON MONDAY. A FEW SHOWERS WILL REMAIN IN THE
FORECAST MONDAY MORNING...BUT THE REST OF THE PERIOD WILL BE DRY
AS THE HIGH BECOMES DOMINANT. A VERY FALL LIKE PATTERN CAN BE
EXPECTED WITH COMFORTABLE DEWPOINTS AND TEMPERATURES RUNNING 5 TO
10 DEGREES BELOW NORMAL THROUGH MOST OF THE PERIOD...WITH THE
BIGGEST DEPARTURES OCCURRING AT NIGHT AS THE DRY AIRMASS ALLOWS
TEMPS TO FALL INTO THE 50S. SOME MODIFICATION WILL OCCUR IN THE
AIRMASS BY SATURDAY WITH TEMPS WARMING BACK TO NEAR NORMAL LEVELS
FOR THE END OF AUGUST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 209 AM EDT SUN AUG 23 2015
HIGH PRESSURE CONTINUES TO SLIDE OFF TO THE NORTHEAST OVERNIGHT.
HIGH CLOUDS ARE MAKING THEIR WAY ACROSS THE REGION...AS WELL AS A
FEW MID LEVEL CLOUDS...AHEAD OF AN APPROACHING COLD FRONT. WHILE
RADAR RETURNS CONTINUE TO APPEAR ON THE RADAR...MOST OF THIS
MOISTURE IS IN THE HIGH LEVELS AND WILL NOT MAKE IT TO THE GROUND.
AS SUCH...DID NOT MENTION ANY VCSH OR SHRA DURING THE EARLY
MORNING PERIOD. DURING THE DAY TODAY...CLOUDS WILL CONTINUE TO
BUILD DOWN. EXPECT MOST STATIONS TO STAY AT OR ABOVE VFR
CIGS...BUT A FEW PLACES MAY SEE SOME PERIODS OF MVFR. THE COLD
FRONT...AS WELL AS THE BEST RAIN/THUNDERSTORMS CHANCES...WILL
MOVE ACROSS THE REGION TOMORROW NIGHT...LATE IN THE TAF PERIOD.
CIGS WILL LIKELY BE REDUCED TO MVFR AT TIMES BY TOMORROW EVENING.
AND GIVEN THE EXPECTED SPOTTY NATURE OF THE
SHOWERS/THUNDERSTORMS...AND THE FACT THEY WILL OCCUR SO LATE IN
THE PERIOD WHEN UNCERTAINTY IS HIGHER...DID NOT INCLUDE MENTION OF
ANY PRECIP AT THIS TIME. WINDS WILL TRANSITION FROM SE TO WESTERLY
DURING THE PERIOD...BUT SHOULD REMAIN LIGHT...LESS THAN 5KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...JP
LONG TERM...ABE
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1156 PM CDT SAT AUG 22 2015
.AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE OVERNIGHT HOURS ALTHOUGH SOME
BR WILL BE POSSIBLE AT TAF LCTNS TWRDS SR.
&&
.PREV DISCUSSION... /ISSUED 1051 PM CDT SAT AUG 22 2015/
UPDATE...UPDATED GFS AND LATEST HRRR CONFIRMS THAT THE SHORT
WAVE ENERGY HAS MOVED A BIT FURTHER SOUTH, SO REMOVED MENTION OF
SHOWERS INLAND FROM THE COASTAL MARSHES.
SWEENEY
PREV DISCUSSION... /ISSUED 819 PM CDT SAT AUG 22 2015/
UPDATE...IR IMAGERY SHOWING MID AND UPPER LEVEL CLOUD COVER WHICH
IS CONFIRMED BY THE EVENING SOUNDING. SOME JET ENERGY IS AVAILABLE
ACROSS THE NORTHERN ZONES LATE TNITE...ALSO SEEN ON THE IR IMAGERY
UPSTREAM OVER NORTH TEXAS. SHORT WAVE ENERGY REMAINS AVAILABLE
ACROSS THE SOUTHERN ZONES. CANNOT RULE OUT ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY TONIGHT SO ADDED MINIMAL POPS. TEMPS ON TRACK.
SWEENEY
PREV DISCUSSION... /ISSUED 652 PM CDT SAT AUG 22 2015/
AVIATION...
STORMS ARE MOVING TO THE NORTHEAST ACROSS SOUTH-CENTRAL LOUISIANA
THIS EVENING. LFT AND ARA WILL STILL HAVE A SLIGHT CHANCE FOR A
SHOWER/TSTMS OTHERWISE LCH/AEX AND BPT LOOK TO REMAIN CLEAR OF
STORMS THROUGH SUNRISE. STORM ENDING BEFORE MIDNIGHT.
K. KUYPER
PREV DISCUSSION... /ISSUED 312 PM CDT SAT AUG 22 2015/
DISCUSSION...
WEAK SFC HIGH OVER THE NE GULF PROVIDING FOR A LIGHT SE FLOW
ACROSS THE REGION. RADAR SHOWING SCT/NUM SHRA/TSRA ACROSS SE TX/C
AND S LA THIS AFTERNOON AS INSTABILITY REMAINS HIGH AND FAVORABLE
LOW LEVEL MOISTURE. WITH A BIT MORE COVERAGE THAN EXPECTED...BUMPED
UP POPS TO 60% FOR MAJORITY OF INLAND AREA NORTH OF THE INTRACOASTAL
WATERWAY THIS AFTERNOON. TEMPS ALL OVER THE PLACE FROM THE RAIN
COOLED 70S TO LOWER 90S ACROSS C LA WHERE THE RAIN HASN`T REACHED
YET. CONVECTION EXPECTED TO DIMINISH THIS EVENING AND THE
OVERNIGHT HOURS.
BY SUN...DRIER AIR ALOFT EXPECTED TO MINIMALIZE PRECIP CHANCES TO
20% DURING THE AFTERNOON. HIGHS IN THE MID 90S EXPECTED. WITH
HIGHER THAN NORMAL DEWPTS IN THE UPPER 70S DURING THE MORNING...TO
MID 70S DURING THE AFTERNOON...HEAT INDEX VALUES LIKELY TO RANGE
100-105 FOR MOST OF THE DAYLIGHT HOURS SUN. GENERALLY THE SAME
EXPECTED FOR MON AS WELL. HOWEVER...A DEEPENING LONGWAVE TROF OVER
THE C AND E U.S. EXPECTED TO ALLOW A COOL FRONT TO MOVE S ACROSS
THE REGION MON NIGHT AND TUE. PRECIP CHANCES EXPECTED TO INCREASE
BY MON AFTERNOON ACROSS OUR REGION...AND ALONG THE FROPA MON
NIGHT/TUE MORNING.
POST FRONTAL WX CONTINUES TO LOOK DRY FOR WED INTO THE REMAINDER
OF THE WEEK. OVERNIGHT TEMPS LIKELY TO BE IN THE 60S FOR MOST OF
THE REGION (EXCEPT COASTAL PARISHES/COUNTIES) FOR NEXT THU & FRI
MORNINGS. HIGHS STILL IN THE LOWER 90S...BUT WITH MUCH LOWER
DEWPTS IN THE 50S/60S...IT WILL BE MORE BEARABLE OUTSIDE.
DML
MARINE...
A LIGHT ONSHORE FLOW WILL PERSIST TONIGHT...BECOMING VARIABLE
SUNDAY AND MONDAY AS THE PRESSURE GRADIENT REMAINS WEAK. CHANCES
OF SHOWERS AND THUNDERSTORMS EXPECTED TO INCREASE AGAIN BY LATE
MONDAY INTO TUESDAY AS A COOL FRONT MOVES THROUGH THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 76 96 76 95 / 10 20 10 30
LCH 76 93 77 95 / 10 30 10 30
LFT 75 95 76 95 / 10 30 10 40
BPT 79 92 77 95 / 10 30 10 30
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
AVIATION...04
AREA FORECAST DISCUSSION
NWS CARIBOU ME
433 AM EDT SUN AUG 23 2015
.SYNOPSIS...
THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS A WARM FRONT
TODAY THROUGH MONDAY. A SLOW MOVING FRONTAL SYSTEM IS EXPECTED
APPROACH THE REGION FROM THE WEST ON TUESDAY AND CROSS THE AREA ON
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CHALLENGE THIS TERM WILL BE TSTMS AND HEAVY RAIN POTENTIAL.
THE LATEST RADAR LOOP SHOWED WIDELY SCATTERED SHOWERS MOVING
NORTH ACROSS THE COASTAL AREAS FROM THE GULF OF MAINE. THESE
SHOWERS WERE DISSIPATED AS THEY MOVED INTO DRIER AIR ACROSS
CENTRAL AND NORTHERN MAINE. SOME FOG HAD SETUP MAINLY AWAY FROM
THE COAST AS CLEARING, COOLING AND WET GROUND ALLOWED FOR THE FOG
DEVELOPMENT. KEPT FOG IN THE FORECAST THROUGH EARLY MORNING.
SURFACE ANALYSIS SHOWED TROF OR WEAK FRONTAL BOUNDARY DRAPED
ACROSS THE DOWNEAST REGION. THIS FEATURE IS FORECAST TO LIFT
NORTHWARD TODAY W/MORE HUMID AIR OVERSPREADING THE REGION AS LOW
PRES LIFTS NE ACROSS THE WESTERN ATLC. THE 00Z NAM AND HRRR 3KM
HAD THINGS INITIALIZED WELL. USED THIS BLEND FOR TODAY`S FORECAST
W/PRECIP LIFTING FROM S TO N.
SHOWERS WILL MOVE FROM S TO N TODAY. HIGH PRES ANCHORED OVER THE
NW ATLC WILL ACT AS A BLOCK INITIALLY AS PRECIP DIES OUT HITTING A
DRY AND STABLE AIRMASS IN PLACE ACROSS THE NORTH AND WEST. FURTHER
S ACROSS CENTRAL AND DOWNEAST AREAS, SOUNDING DATA SHOWED THE
COLUMN MOISTENING THROUGH 700MBS W/INCREASING INSTABILITY. SB
CAPES OF 500-1000 JOULES ARE FORECAST TO SETUP THIS AFTERNOON
ACROSS THE AFOREMENTIONED AREAS. PWATS ARE 1.7+ W/LIS DOWN TO -2
TO -3. 0-6KM SHEAR IS WEAK < 10 KTS. A WARM CLOUD LAYER W/HIGH
FREEZING LEVELS(13-14K FT) WILL LEAD TO LOADING OF PRECIP
W/POTENTIAL FOR HEAVY TO TORRENTIAL RAINFALL IN SPOTS. DECIDED TO
STAY W/TSTMS THIS AFTERNOON INTO THE EVENING AND ADDED HEAVY
RAINFALL WORDING.
SHOWERS AND SOME TSTMS ARE EXPECTED TO SPREAD INTO NORTHERN AND
WESTERN MAINE TONIGHT. SOUNDING DATA SHOWED MOST OF THE CONVECTION
TO BE ELEVATED W/THE HIGHEST THREAT ACROSS THE HOULTON AND
MILLINOCKET REGION W/LESS INSTABILITY FURTHER N. ONCE AGAIN HEAVY
RAIN THREAT CONTINUES. DOWNEAST AND COASTAL AREAS WILL BECOME MORE
STABLE W/FOG AND DRIZZLE. USED A CONSENSUS BLEND ON THE QPF DUE
TO LOW CONFIDENCE IN PLACEMENT OF HEAVIER RAINFALL AMOUNTS. SOME
AREAS COULD DEFINITELY PICK AN INCH OR MORE OF RAIN IN TSTMS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
UNSETTLED WX PATTERN CONTINUES FOR THE START OF THE WORK WEEK.
EXPECT THE CHANCE FOR SHOWERS AND AFTERNOON THUNDERSTORMS BOTH
MONDAY AND AGAIN ON TUESDAY AS A TROF OF LOW PRESSURE TRACKS
SLOWLY EAST FROM THE GREAT LAKES REGION. HIGH TEMPERATURES BOTH
MONDAY AND TUESDAY WILL RANGE FROM THE MID TO UPPER 70S. IT WILL
ALSO CONTINUE TO FEEL ON THE MUGGY SIDE WITH DEW POINT EXPECTED TO
REMAIN IN THE 60S BOTH DAYS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
TUESDAY NIGHT WILL SEE THE THREAT FOR SHOWERS AND EVENING
THUNDERSTORMS AS A LEAD SHORT WAVE AHEAD OF THE APPROACHING UPPER
TROF MOVES ACROSS THE REGION. UNSETTLED WEATHER WITH CONTINUED
CHANCES FOR SHOWERS AND AFTERNOON THUNDERSTORMS WILL CONTINUE INTO
THURSDAY EVENING AS THE TROF SWINGS ACROSS THE REGION. HIGH
PRESSURE WILL BUILD IN FOR FRIDAY. A COLD FRONT WILL CROSS THE
REGION SATURDAY.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: IFR/LIFR FOR SOME OF THE TERMINALS(KPQI-KHUL) THIS
MORNING DUE TO FOG. ACROSS KBGR AND KBHB, VFR ATTM. EXPECTING KBGR
AND KBHB TO DROP TO MVFR AND THEN IFR LATER THIS MORNING INTO THE
AFTERNOON AND HOLD AT IFR TONIGHT. THE NORTHERN TERMINALS WILL
IMPROVE TO VFR AFTER 12Z AND STAY THERE THROUGH THE AFTERNOON.
MVFR CONDITIONS ARRIVE ACROSS KHUL THIS EVENING AND THEN TO IFR BY
MIDNIGHT W/KPQI-KCAR-KFVE DROPPING TO MVFR BY LATE EVENING AND
THEN IFR OVERNIGHT. TSTMS W/CLOUD TO GROUND LIGHTNING AND HEAVY
RAINFALL ARE POSSIBLE THIS AFTERNOON INTO TONIGHT.
SHORT TERM: VFR CONDITIONS WILL PREVAIL MOST OF THE TIME BUT
MVFR/IFR IS POSSIBLE IN PATCHY NIGHTTIME/EARLY MORNING FOG AS WELL
AS SCT SHOWERS/TSTMS.
&&
.MARINE...
NEAR TERM: A 3 FOOT SWELLS OUT ON THE WATERS ATTM IS EXPECTED TO
BUILD TO AROUND 4 FT THIS AFTERNOON. SWELLS ARE EXPECTED TO BUILD
TO A RANGE OF 4-5 FT TONIGHT. WINDS WILL REMAIN LIGHT 10 KTS OR
LESS RIGHT INTO TONIGHT. FOG WILL HAMPER NAVIGATION FROM TIME TO
TIME. TSTMS ARE POSSIBLE LATER THIS AFTERNOON INTO THE EVENING.
SHORT TERM: WIND/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY
LEVEL.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1250 AM EDT SUN AUG 23 2015
.SYNOPSIS...
THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS A WARM FRONT
TODAY THROUGH MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE: SOME SHOWERS MOVING ACROSS THE OUTER ISLANDS OF
THE COAST PER THE LATEST RADAR LOOP. DECIDED TO BRING POPS AND
TIMING UP A BIT BASED ON THE LATEST RADAR. THE RAP & HRRR 3KM
MODEL DOING OK W/THIS SETUP. MESO ANALYSIS SHOWED AN INVERTED TROF
ALIGNED ACROSS THE COAST NOSING UP INTO EASTERN SECTION. LAPS DATA
HAD SOME LLVL CONVERGENCE IN THE AFOREMENTIONED REGION WHICH WILL
ALLOW SHOWERS TO STAY IN TACT. ATMOSPHERE LOOKS TOO STABLE FOR
TSTMS ATTM PER THE LAPS SHOWING LIFTED INDICES ABOVE 0. SOME FOG
SHOWING UP ON THE COAST AND INLAND AS WELL. DAYCREW HAD THIS
HANDLED WELL. ADJUSTED THE HRLY TEMPS TO BRING THEM UP SOME ACROSS
THE DOWNEAST AND COAST GIVEN CLOUDS AND SHOWERS. FURTHER N AND W,
BASICALLY CLEAR W/READINGS IN THE MID TO UPPER 50S.
FRONTAL BOUNDARY WILL BEGIN TO LIFT BACK NORTH THROUGH TODAY.
HAVE NOTED THE 12Z GUIDANCE WAS FASTER IN BRINGING THIS FRONT
THROUGH, SO HAVE SHIFTED THE CHANCES FOR SHOWERS FURTHER NORTH BY
THE AFTERNOON; MAINLY ALONG AND SOUTH OF A HOULTON TO GREENVILLE
LINE. SB CAPES ARE PROGGED TO REACH 800-1200 J/KG, SO
THUNDERSTORMS WILL BE A POSSIBILITY AWAY FROM THE COAST. 0-6KM
SHEAR ISN`T ALL THAT IMPRESSIVE, SO STRONG STORMS AREN`T EXPECTED.
HOWEVER, PWATS WILL ONCE AGAIN INCREASE TO 1.75 INCHES OR MORE ON
THE SOUTH SIDE OF THE FRONT, SO HEAVY RAIN WILL BE A THREAT.
STEERING FLOW WILL BE FAIRLY LIGHT, SO SLOW MOVING CELLS WILL BE A
CONCERN. HIGHS WILL MAINLY BE IN THE UPPER 70S TO AROUND 80.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
THE FA WILL REMAIN IN A BROAD SW TO NE FLOW REGIME HI ALF AHEAD OF
A STRONG UPPER TROF/CLOSED LOW OVR THE MIDWEST FROM SUN NGT THRU
TUE...WITH SEVERAL WEAK S/WV IMPULSES TO IMPACT THE FA. FOR THIS
REASON...WE DO NOT LOWER POPS BLO CHC EVEN DURG THE LATE NGT AND
MORN HRS...BUT WE DO INCREASE POPS INTO THE LIKELY CATEGORY DURG
THE LATE AFTN AND ERLY EVE HRS MON AND TUE TO ACCOUNT FOR SOME
DIURNAL HTG ADDING TO SBCAPES WHICH COULD REACH AS HI AS 600 TO
1000 J/KG. FOR THIS REASON...WE ADDED CHC TSTMS WITH CHC AND ABV
POPS DURG THESE HRS. ALTHOUGH WE DO NOT ADVERTISE ENHANCED WORDING
FOR HVY RNFL ATTM...IT WILL LIKELY BE INCLUDED ONCE THIS PTN OF
THE FCST APCHS THE NEAR TERM...GIVEN THE POTENTIAL HI PWATS AND
THE DIFFLUENT FLOW ALF PATTERN WHICH BOTH FAVOR DEEP ENOUGH CNVCTN
FOR HI RNFL RATES WITH SHWRS/TSTMS. HI AND LOW TEMPS WILL CONT ABV
AVG...BUT WILL SLOWLY TAPER BACK TO CLOSER TO NORMAL SEASONAL
VALUES BY TUE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A SLOW MOVING UPPER LEVEL TROUGH WILL APPROACH FROM THE GREAT LAKES
DURING THE MID WEEK PERIOD THEN SLOWLY TRACK ACROSS THE REGION
THROUGH THURSDAY BRINGING UNSETTLED WEATHER. TUESDAY NIGHT AND
WEDNESDAY WILL BE MOSTLY CLOUDY WITH SOME SCATTERED SHOWERS AND
PERHAPS A THUNDERSTORM, ESPECIALLY ACROSS CENTRAL AND NORTHERN
AREAS. CLOUDS AND SCATTERED SHOWERS WILL CONTINUE INTO THURSDAY OVER
CENTRAL AND NORTHERN AREAS WHILE THE DOWNEAST REGION MAY HAVE SOME
BREAKS OF SUNSHINE. THE TROUGH SHOULD WEAKEN AND MOVE OUT TO THE
NORTHEAST ON FRIDAY ALLOWING WEAK SURFACE RIDGING TO BRING PARTIAL
CLEARING OVER THE AREA AND SEASONABLE TEMPS. THE DRY WEATHER MAY
LAST INTO SATURDAY BEFORE ENOUGH TROUGH, DIGGING DOWN FROM CENTRAL
CANADA, APPROACHES WITH A CHANCE FOR SHOWERS ON SUNDAY.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: 1030PM UPDATE: GIVEN IFR CIGS AT KRKD AND LOWERING CIGS
VISIBLE ALONG THE COAST ON WEBCAMS BEFORE SUNSET, EXPECT THAT
CONDITIONS ARE LOWERING AT KBHB. OTHERWISE, PATCHY FOG HAS BEEN
NOTED IN INTERIOR AREAS, BUT NOT CURRENTLY EXPECTED TO BE
PREVAILING CONDITIONS OUTSIDE OF COASTAL AND DOWN EAST AREAS.
MAINTAIN VFR CONDITIONS FOR 4 NORTHERN TERMINALS.
730PM UPDATE: KBHB OBS STILL DOWN, SO USED OBS FM
OTHER COASTAL ZONE SITES TO ESTIMATE SOME BORDERLINE MVFR CIGS
CURRENTLY. EXPECT AT LEAST IFR CIGS TO DEVELOP FOR KBHB, AND IFR
VIS IS CERTAINLY A POSSIBILITY. EXPECT MVFR CIGS AND BORDERLINE
IFR VIS IN KBGR BY 06Z, WITH IMPROVEMENT AT BOTH SRN TERMINALS
AFTER SUNRISE. KEPT VFR CONDITIONS AT NRN TERMINALS THROUGH THE
PERIOD, AND KEPT RAIN OUT OF NRN SITES, EXCEPT SHWRS AT KHUL
LATER IN THE AFTERNOON.
ORIGINAL DISCUSSION: VFR CONDITIONS AT THE NORTHERN TERMINALS
THROUGH THE PERIOD, THOUGH SOME MVFR IN LOCALIZED FOG LATE
TONIGHT/EARLY SUNDAY. KBHB AND KBGR WILL ONCE AGAIN DROP TO
IFR/LIFR AFTER 06Z TONIGHT IN FOG.
SHORT TERM: THE AVG CLG/VSBY FOR THIS PTN OF THE FCST FROM SUN NGT
THRU TUE WILL BE MVFR FOR ALL THE TAF SITES WITH PERIODIC SHWRS...
LIKELY LOWERING TO IFR LATE AT NGT WITH PATCHY FOG...AND POSSIBLE
RISING TO AS HIGH AS LOW VFR BETWEEN SHWRS DURING AFTN AND ERLY
EVE HRS.
&&
.MARINE...
NEAR TERM: NO HEADLINES WILL BE NEEDED ACROSS THE WATERS TONIGHT
OR SUNDAY. THE CONCERN REMAINS AREAS OF DENSE FOG, WHICH WILL
REDUCE VISIBILITY TO BELOW 1SM AT TIMES.
SHORT TERM: NO HDLNS ANTICIPATED ATTM...ALTHOUGH WV HTS COULD APCH
5 FT OVR OUTER MOST WATERS LATE SUN NGT THRU MON WITH A MDT SWELL
COMPONENT. PATCHY...MSLY NGT AND MORN MARINE FOG CAN ALSO BE
XPCTD. WE WENT WITH ABOUT 90 PERCENT OF WW3 WV GUIDANCE FOR THE
OUTER MZS AND 65 TO 85 PERCENT FOR NEAR SHORE WATERS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 AM EDT SUN AUG 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EDT SUN AUG 23 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW POTENT SHRTWV/
CUTOFF H5 LO DRIFTING INTO WRN MN. THIS DISTURBANCE CAUSED 12Z-24Z
H5/H3 HGT FALLS OF 150M/220M AT BISMARCK. SHARPLY DIFFLUENT UPR
FLOW/AREA OF DPVA AND SHARP DEEP LYR QVECTOR CNVGC IN ADVANCE OF
THIS FEATURE AND OVER ATTENDANT COLD FNT/WARM CONVEYOR BELT MSTR
RIBBON /00Z PWAT 1.50 INCH TO AS HI AS 1.93 INCH AT INL WITHIN THIS
MSTR BAND/ IS SUPPORTING BAND OF SCT-NMRS SHOWERS/TS STRETCHING FM
THE MN ARROWHEAD/ADJOINING ONTARIO THRU WRN LK SUP INTO THE MID MS
RIVER VALLEY. THE 00Z GRB RAOB WAS RELATIVELY DRY AND CAPPED...SO
THE WX OVER UPR MI IN ADVANCE OF THE FNT/SHOWERS HAS BEEN RELATIVELY
QUIET EXCEPT FOR GUSTY S WINDS UNDER THE TIGHT PRES GRADIENT BTWN
RETREATING HI PRES OVER THE NE STATES AND 995MB SFC LO DRIFTING NEWD
IN NW ONTARIO. AS THE SHOWERS HAVE MOVED E TOWARD UPR MI INTO
THIS MORE STABLE AIRMASS IN THE PRESENCE OF NOCTURNAL COOLING...THE
LTG INTENSITY HAS DIMINISHED. LOOKING FARTHER TO THE W...A WELL
DEFINED DRY SLOT HAS ENDED THE PCPN FARTHER W IN MN...BUT MORE
SHOWERS AND EVEN A FEW TS ARE EVIDENT OVER THE DAKOTAS MOVING INTO
FAR WRN MN UNDER SHARP COMMA HEAD CLD MASS ASSOCIATED WITH THE
SHRTWV.
MAIN FCST CONCERNS TODAY WL BE ON TIMING/COVERAGE OF WARM CONVEYOR
BELT SHOWERS/TS AND THEN WRAP ARND MSTR/SHOWERS TNGT AS CUTOFF LO IN
MN DRIFTS TO THE E AND OVER NRN LK SUP BY 12Z MON. STRONG WNW WINDS
WL IMPACT MAINLY THE WRN ZNS LATE TODAY/TNGT UNDER THE TIGHTER PRES
GRADIENT ON THE SW FLANK OF DEEP SFC LO PRES STACKED UNDER THE
CLOSED UPR LO.
TODAY...AS CLOSED/STACKED LO DRIFTS TO JUST NW OF THUNDER BAY BY
00Z...SFC COLD FNT IS FCST TO REACH IWD BY 12Z...CENTRAL UPR MI BY
18Z AND THEN NEWBERRY BY 00Z. AREA OF DPVA/DEEP LYR QVECTOR CNVGC
AND SHARP UPR DVGC IN LEFT EXIT OF SUPPORTING H3 JET MAX MOVING E ON
THE SRN FLANK OF THE CLOSED LO OVER THE WARM CONVEYOR BELT MSTR
RIBBON AHEAD OF THE FNT SHOULD SUPPORT RELATIVELY NARROW BAND OF
NMRS SHOWERS. EXPECT THESE SHOWERS...WITH SOME EMBEDDED TS
MAINTAINED BY HEALTHY DYNAMIC FORCING DESPITE MODEST MUCAPE NO MORE
THAN 200-400 J/KG...TO SWING W-E ACRS THE CWA WITH THE FNT. ARRIVAL
OF DRY SLOTTING BEHIND THE FROPA/WARM CONVEYOR BELT WL BRING A QUICK
DIMINISHING TREND TO THE PCPN. SOME PREVIOUS MODELS HAD SUGGESTED
DAYTIME HEATING IN THE PRESENCE OF LINGERING DEEP LYR QVECTOR CNVGC
WITHIN THE DRY SLOT MIGHT RESULT IN MORE INSTABILITY SHOWERS/TS...
BUT FCST SDNGS NOW INDICATE THE DRYING WL BE TOO OVERWHELMING. AREA
OF BACKWASH MSTR UNDER CYC W FLOW NOW PUSHING INTO WRN MN WL THEN
OVERSPREAD THE W HALF. AS H85 TEMPS FALL TOWARD 5-6C OVER THE W BY
00Z IN THE STRONG LLVL CAA...LLVL LAPSE RATES WL INCRS AND ALLOW FOR
EXTENSIVE SC/SOME SHOWERS/MORE EFFICIENT MIXING OF 30-35KT H925 W
WINDS TO THE SFC. TEMPS ARE LIKELY TO FALL THIS AFTN OVER THE W WITH
THE CAA/CLDY SKIES.
TNGT...THE CLOSED/STACKED LO IS FCST TO DRIFT SLOWLY SE AND OVER NRN
LK SUP BY 12Z MON. THE TIGHTER PRES GRADIENT/H925 W WINDS UP TO 30-
35KTS UNDER THE H85 THERMAL TROF ON THE SW FLANK OF THE SFC LO ARE
FCST TO IMPACT MAINLY THE W AND SCENTRAL CWA AND RESULT IN SOME
GUSTY WINDS...ESPECIALLY AT EXPOSED LOCATIONS NEAR LK SUP. H85 TEMPS
AS LO AS 2-4C /WATER TEMPS OVER WRN LK SUP ARE AS HI AS 15-17C/
ADVECTING INTO THE FAR W WL SUPPORT SOME LK EFFECT SHOWERS OVER
MAINLY THE HIER TERRAIN OF THE NW HALF.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 312 AM EDT SUN AUG 23 2015
THE NEARLY VERTICALLY STACKED SURFACE AND UPPER LOW AT 12Z MONDAY
WILL BE SLOWLY MOVING EAST ACROSS NORTHERN ONTARIO AND WILL CONTINUE
THAT PATH THROUGH TUESDAY NIGHT BEFORE FINALLY BECOMING CAUGHT UP IN
THE NORTHERN STREAM FLOW AND QUICKLY LIFTING NORTHEAST THROUGH
QUEBEC ON WEDNESDAY/THURSDAY. THIS WILL LEAD TO A VERY FALL LIKE
START TO THE WORK WEEK WITH BREEZY WEST-NORTHWEST WINDS...PERIODS OF
LAKE EFFECT/ENHANCED RAIN AND TEMPERATURES WELL BELOW NORMAL.
WITH ABUNDANT MOISTURE WRAPPING AROUND THE UPPER/SURFACE
LOW...EXPECT PLENTY OF LOW CLOUDS (AND SCATTERED TO NUMEROUS
SHOWERS) ACROSS THE U.P. FOR MONDAY INTO AT LEAST WEDNESDAY MORNING.
THE MAIN QUESTION WILL BE HOW COLD THE 850MB TEMPS WILL BE TO THE
SOUTHWEST OF THE LOW IN ONTARIO. MODELS VARY IN THE EXACT
VALUE...WITH THE NAM THE COLDEST AT 0-1C AND THE REST IN THE 2.5-4C
RANGE FOR MONDAY AND THEN GRADUALLY WARMING THROUGH TUESDAY. THE
EXACT VALUE DOESN/T MATTER TOO MUCH...AS THE TEMPERATURES ALOFT WILL
BE COLD ENOUGH FOR LAKE ENHANCED/EFFECT RAIN WITH WESTERN LAKE
SUPERIOR TEMPERATURES AROUND 15-17C. THEREFORE...WILL SHOW LIKELY TO
DEFINITE VALUES FOR THE FAVORED WEST-NORTHWEST WIND AREAS ON MONDAY
AND TRANSITION TO MORE NORTHWESTERLY FOR MONDAY NIGHT INTO TUESDAY.
IN ADDITION...WILL HAVE THE HIGHEST POPS OVER THE FAVORED UPSLOPE
LOCATIONS FOR THE MONDAY INTO TUESDAY PERIOD (AREAS FROM THE SPINE
OF THE KEWEENAW THROUGH IRONWOOD). THAT UPSLOPE FORCING WILL BE DUE
TO THE WEST-NORTHWEST WINDS ON MONDAY AND THEN TRANSITION TO MORE
NORTHWESTERLY ON MONDAY NIGHT AS THE SURFACE-850MB LOW SHIFTS EAST
AND CLOSER TO JAMES BAY AND THE SURFACE TROUGH MOVES EAST ACROSS THE
UPPER GREAT LAKES. THAT NORTHWESTERLY LOW LEVEL FLOW WILL CONTINUE
INTO WEDNESDAY...POTENTIALLY TURNING A LITTLE MORE NORTH-NORTHWEST.
THE STRONGEST WINDS WILL OCCUR MONDAY INTO MONDAY NIGHT (GUSTS OF 20-
30KTS OVER THE WESTERN U.P.) WITH THE TIGHTEST PRESSURE GRADIENT AS
THE SURFACE LOW IS JUST TO THE NORTH OF LAKE SUPERIOR. THEN THE
WINDS WILL GRADUALLY DIMINISH TUESDAY INTO WEDNESDAY AS THE LOW
WEAKENS/BROADENS AS IT MOVES INTO NORTHEAST ONTARIO.
THE THIRD ITEM OF NOTE TO START THE WEEK WILL BE THE VERY FALL LIKE
HIGHS ACROSS THE AREA ON MONDAY. WITH PLENTY OF CLOUDS AND
SHOWERS...HAVE OPTED TO FOLLOW THE RAW MODELS FOR HIGHS ON
MONDAY...WHICH GIVES LOW-MID 50S OVER THE WEST AND MID-UPPER 50S
OVER THE EAST. THIS IS ABOUT 20 DEGREES BELOW NORMAL AND IN SOME
AREAS THEY WILL BE NEARING RECORD COLD HIGH TEMPERATURES. THE RECORD
FOR OUR OFFICE IS 56 DEGREES (1978/1971) AND WE WILL BE NEAR THAT
BOTH AT MIDNIGHT TONIGHT AND AGAIN WITH THE HIGH ON MONDAY
AFTERNOON. LOOKING AT THE TIME SHIFTED COOP DATA (NEED TO USE 8/25
VALUES)...MANY SITES HAVE RECORD VALUES IN THE 50S AND SOME OF THE
MORE NOTABLE ONES ARE...IRONWOOD 55 IN 1915...HOUGHTON 53 IN 1987
(MIDNIGHT-MIDNIGHT)...IRON MOUNTAIN 59 IN 1940...MUNISING 57 IN
1940...AND 55 IN NEWBERRY IN 1917. THUS...WITH THE GOING FORECAST
HIGH TEMPERATURES...THERE WILL BE SEVERAL SPOTS THAT WILL BE NEAR
RECORD LOW MAXIMUM VALUES. TEMPERATURES WILL WARM A FEW DEGREES FOR
TUESDAY...BUT HIGHS WILL STILL BE IN THE UPPER 50S AND LOWER 60S.
DRY AIR FROM THE HIGH BUILDING INTO THE PLAINS ON WEDNESDAY WILL
FINALLY BRING AN END TO THE PROLONGED PERIOD OF CLOUDS AND SHOWERS
FROM WEST TO EAST ON WEDNESDAY (ALTHOUGH THE CLOUDS MAY LINGER OVER
THE FAR EAST INTO THE EVENING HOURS). THAT HIGH PRESSURE RIDGE WILL
MOVE OVER THE AREA WEDNESDAY NIGHT AND REMAIN INTO THURSDAY.
CLEARING SKIES AND LIGHT WINDS ON WEDNESDAY NIGHT WILL LEAD TO A
GOOD RADIATIONAL COOLING NIGHT ACROSS THE AREA AND HAVE LOWER LOWS
SOME FROM THE PREVIOUS FORECAST (CLOSER TO THE MEX AND GEM VALUES
WHICH TEND TO PERFORM BETTER IN THOSE SITUATIONS). ABUNDANT SUNSHINE
ON THURSDAY WILL LEAD TO HIGHS RETURNING TO MORE NORMAL VALUES FOR
LATE AUGUST.
FINALLY...A COLD FRONT WILL DROP SOUTHEAST ACROSS THE UPPER GREAT
LAKES LATE THURSDAY NIGHT INTO FRIDAY...BRINGING A CHANCE FOR
SHOWERS/THUNDERSTORMS TO THE U.P.. THINK THE COVERAGE/AMOUNTS WILL
LIMITED DUE TO THE LACK OF RETURN FLOW AND EXISTING DRY AIR.
THUS...WON/T GO MORE THAN LOW CHANCE POPS FOR NOW AS THE FRONT MOVES
THROUGH. A WEAK RIDGE LOOKS TO MOVE OVER THE AREA FOR SATURDAY
BEHIND THE FRONT AND SHOULD LEAD TO A DRY DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 124 AM EDT SUN AUG 23 2015
S-SW WINDS WILL REMAIN GUSTY INTO THE OVERNIGHT TO 25-30KT THEN
SLOWLY DIMINISH PRIOR TO DAYBREAK SUNDAY...BEFORE INCREASING AGAIN
BEHIND A COLD FRONTAL PASSAGE. EXPECT VFR CONDITIONS TO LOWER TO
MVFR LATE TONIGHT WITH THE ARRIVAL OF SHRA/TSRA ALONG APPROACHING
COLD FRONT FROM THE W. ALTHOUGH SOME BRIEF IMPROVEMENT TO VFR MAY
HAPPEN AT IWD LATE SUN MORNING AND AT SAW IN THE AFTERNOON...WRAP
AROUND MOISTURE AND SCATTERED LAKE-ENHANCED SHRA WILL LIKELY BRING
CEILINGS BACK TO MVFR BY LATE AFTERNOON/SUN EVENING AT IWD AND CMX
IN ONSHORE WESTERLY FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 312 AM EDT SUN AUG 23 2015
A FALL LIKE LOW PRESSURE SYSTEM CURRENTLY TO THE NORTH OF THE LAKE
OF THE WOODS WILL BRING WINDY CONDITIONS TO LAKE SUPERIOR THROUGH
THE FIRST HALF OF THE UPCOMING WORK WEEK AS IT SLOWLY MOVES EAST
ACROSS NORTHERN ONTARIO. GUSTY SOUTHERLY WINDS WILL CONTINUE THIS
MORNING AHEAD OF A COLD FRONT OVER WESTERN LAKE SUPERIOR...BUT AS
IT MOVES EAST ACROSS THE REST OF THE LAKE TODAY IT WILL SHIFT WINDS
TO THE WEST AND LEAD TO GALES TO 35 KNOTS FOR PORTIONS OF WESTERN
LAKE SUPERIOR THIS AFTERNOON AND EXPANDING ACROSS THE REST OF
THE WESTERN HALF OF THE LAKE TONIGHT AND CONTINUING INTO MONDAY.
WITH THE LOW SLOWLY WEAKENING MONDAY NIGHT INTO TUESDAY AS IT NEARS
JAMES BAY...THE WINDS WILL GRADUALLY DIMINISH AND TURN TO THE
NORTHWEST. HIGH PRESSURE WILL BUILD OVER THE UPPER GREAT LAKES
REGION FOR WEDNESDAY AND THURSDAY..WHICH WILL LOWER WINDS BELOW
20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 2 PM EDT /1 PM CDT/ THIS AFTERNOON TO 8 PM EDT
/7 PM CDT/ MONDAY FOR LSZ162-263-264.
GALE WARNING FROM 2 AM TO 8 PM EDT MONDAY FOR LSZ265.
GALE WARNING FROM 8 PM THIS EVENING TO 5 PM EDT MONDAY FOR
LSZ243-244.
GALE WARNING FROM 8 AM EDT /7 AM CDT/ TO 5 PM EDT /4 PM CDT/
MONDAY FOR LSZ240>242.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...VOSS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT SUN AUG 23 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 330 AM EDT SUN AUG 23 2015
A COLD FRONT WILL MOVE EAST THROUGH LOWER MICHIGAN TODAY BRINGING A
PERIOD OF SHOWERS AND THUNDERSTORMS AND USHERING IN FALL LIKE
WEATHER. COOL AND BREEZY CONDITIONS WITH CONSIDERABLE CLOUDINESS AND
SCATTERED SHOWERS CAN BE EXPECTED MONDAY THROUGH WEDNESDAY WITH
HIGHS STRUGGLING TO REACH 70 DEGREES.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 330 AM EDT SUN AUG 23 2015
THE FOCUS IN THE SHORT TERM CONTINUES TO BE ON CONVECTIVE POTENTIAL
TODAY AND THE MARGINAL RISK OF A FEW STRONG TO SEVERE STORMS.
LATEST GUIDANCE SHOWS A RATHER NARROW NORTH-SOUTH ORIENTED BAND OF
INSTABILITY... ONLY ABOUT 50 MILES WIDE... MARCHING EAST THROUGH THE
AREA TODAY AHEAD OF APPROACHING SFC COLD FRONT. MU CAPES WITHIN THIS
BAND MAX OUT AROUND 1000 J/KG...REACHING THE LAKESHORE AROUND NOON
AND EXITING THE LANSING/JACKSON AREA AROUND 6-7 PM.
HIGH POPS FOR SHOWERS AND TSTMS...GREATER THAN 60-70 PCT...APPEAR TO
BE IN ORDER TODAY AS SHORTWAVE ROTATES TROUGH BASE OF INCREASINGLY
NEGATIVELY TILTED UPR TROUGH PIVOTING NE THROUGH MN/WI. HOWEVER
THERE IS ONLY ABOUT A 3-4 HOUR WINDOW WHEN SHOWERS AND TSTMS WILL BE
IMPACTING ANY GIVEN LOCATION.
AS FAR AS SEVERE WEATHER POTENTIAL... MARGINAL IS CERTAINLY THE
APPROPRIATE TERM. THE BETTER STRONG DEEP LAYER SHEAR IN EXCESS OF
50 KTS LAGS BEHIND THE COLD FRONT... BUT STILL ROUGHLY 35 KTS IS
PROGGED TO BE CONICIDENT WITH THE NARROW RIBBON OF INSTABILITY AND
THIS DOES SUPPORT THE POTENTIAL FOR A FEW ORGANIZED STORMS. RUC FCST
SOUNDINGS SHOW SKINNY CAPE PROFILES AND MARGINAL MID LEVEL LAPSE
RATES OF ONLY AROUND 6 C/KM SUGGESTING WEAK UPDRAFT POTENTIAL.
BELIEVE THE MAIN THREAT FOR A FEW STRONG OR PERHAPS SEVERE CELLS TO
DEVELOP IS EAST OF HIGHWAY 131 THIS AFTERNOON. THIS IS WHERE BETTER
CHANCE OF STONGER INSOLATION EXISTS THAT COULD OVERCOME WEAK CIN AND
YIELD DECENT SFC BASED INSTABILITY. MAIN THREAT IS LOCALIZED
DAMAGING WIND GUSTS.
THE REST OF THE FCST IS PRETTY STRAIGHTFORWARD. DEEP CYCLONIC FLOW
AND STRONG COLD ADVECTION... COMBINED WITH LAKE INDUCED
INSTABILITY... WILL YIELD EXTENSIVE STRATO CUMULUS CLOUDS MONDAY
INTO TUESDAY ALONG WITH SCATTERED TO NUMERSOU RAIN SHOWERS.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM EDT SUN AUG 23 2015
THE TREND OVER THE PAST DAY HAS BEEN FOR THE COOLER AIR AND RAIN
SHOWER ACTIVITY TO LINGER OVER THE AREA A BIT LONGER INTO THE LONG
TERM. THIS OCCURS AS THE UPPER LOW HOLDS IN FOR AT LEAST ANOTHER DAY
AND IS REINFORCED BY ADDITIONAL SHORT WAVE ACTIVITY DIVING IN ON ITS
BACKSIDE. THIS WILL HOLD SHOWER ACTIVITY INTO WED ALONG WITH TEMPS
STRUGGLING TO REACH 70 WITH H850 TEMPS REMAINING BELOW 8C.
LATEST MODEL TRENDS DO PUSH OUT THE LOW BY THU AND ALLOW THE AREA TO
DRY OUT AND TEMPS TO MODERATE A BIT AS WE BECOME UNDER THE INFLUENCE
OF THE CONFLUENCE DOWNSTREAM OF THE UPPER RIDGE AXIS TO OUR WEST.
THIS DRY WEATHER COULD LAST INTO FRI...HOWEVER THE CHC OF RAIN WILL
BE GRADUALLY INCREASING THROUGH FRI AND FRI NIGHT.
THE INCREASE IN RAIN CHCS THROUGH FRI AND FRI NIGHT AND INTO SAT
COMES AS A RESULT OF ADDITIONAL SHORT WAVE ENERGY DIVING SE OUT OF
CANADA AND BRINGING A COLD FRONT IN. THERE ARE SOME DISCREPANCIES
WITH REGARD TO THE TIMING DEPENDING ON THE POTENTIAL DEVELOPMENT OF
THE WAVE INTO A LOW VIA THE ECMWF. WE ARE NOT BETTING ON THIS
SOLUTION YET AS THE EURO TENDS TO OVERDEVELOP DEVELOPING SYSTEMS.
SOME WARMER AIR WILL COME IN AHEAD OF THIS WAVE AND ASSOCIATED SFC
FRONT FOR EARLY NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 152 AM EDT SUN AUG 23 2015
OUR MAIN FOCUS WITH THIS SET OF FCSTS CONTINUES TO BE THE SHOWERS
AND STORMS THAT ARE EXPECTED TO ACCOMPANY THE COLD FRONT MAINLY
THIS AFTERNOON INTO EARLY THIS EVENING.
THE WEATHER SHOULD BE QUIET UNTIL THE RAIN MOVES IN WITH VFR
CONDITIONS EXPECTED THROUGH MOST OF THE MORNING. WE ARE EXPECTING
THAT THE SHOWERS WILL BEGIN TO MOVE IN ACROSS THE LAKESHORE TOWARD
LATE MORNING...AND THEN SPREAD EAST THROUGH THE AFTERNOON. WE ARE
EXPECTING MAINLY SHOWERS FOR THE WRN TERMINALS WITH A CHC OF
THUNDER. THE ERN TERMINALS WILL HAVE A BETTER THREAT FOR THUNDER
WITH SOME DIURNAL HEATING. MVFR WILL BE LIKELY IN THE
SHOWERS/STORMS WITH SOME SPOTTY IFR POSSIBLE.
SHOWERS/STORMS WILL LIKELY MOVE OUT AFTER ONLY IMPACTING ANY ONE
LOCATION FOR A FEW HOURS. IT LOOKS LIKE ALL OF THE RAIN SHOULD BE
EAST OF THE TERMINALS BY 23-00Z. SKIES WILL CLEAR AND SOME GUSTY
WINDS WILL BE POSSIBLE BEFORE SUNSET. WINDS SHOULD THEN DECOUPLE.
&&
.MARINE...
ISSUED AT 330 AM EDT SUN AUG 23 2015
NO CHANGES ARE PLANNED TO THE ONGOING MARINE HEADLINES. INITIALLY
WINDS GET CRANKING THIS MORNING OUT OF THE SOUTH AHEAD OF THE COLD
FRONT... CAUSING HIGHEST WAVES NORTH OF HOLLAND. THEN THE WEST WINDS
BEHIND THE FRONT YIELD WIDESPREAD 6-8 FOOTERS AREA WIDE TONIGHT
THROUGH MONDAY NIGHT. THE OTHER MARINE CONCERN IS FOR WATERSPOUT
POTENTIAL ON TUESDAY AS THE WIND SPEEDS DIMINISH A BIT.
&&
.HYDROLOGY...
ISSUED AT 1111 AM EDT SAT AUG 22 2015
CONCERNS FOR FLOODING REMAIN LOW OVER THE NEXT WEEK.
RAIN CHANCES ARE FAIRLY LIMITED TO SUNDAY WITH MONDAY INTO
TUESDAY MAINLY BEING THE LIGHT AND SCATTERED VARIETY. TOTALS
CONTINUE TO BE IN THE BALLPARK OF HALF AN INCH FOR THE PERIOD
SPANNING SUNDAY TO TUESDAY. DRY WEATHER SETTLES IN AGAIN ONCE THE
SYSTEM DEPARTS TO THE NORTH AND EAST. RAINFALL IS EXPECTED TO DO
NOTHING MORE THAN A BENEFICIAL SOAKING FOR THE FORECAST AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT FROM 8 AM EDT THIS MORNING THROUGH
MONDAY EVENING FOR MIZ037-043-050-056-064-071.
LM...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 8 PM EDT MONDAY
FOR LMZ844>849.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...JAM
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS GAYLORD MI
205 AM EDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 1051 PM EDT SAT AUG 22 2015
SKIES REMAIN CLEAR ACROSS OUR ENTIRE CWA LATE THIS EVENING BETWEEN HIGH
PRESSURE CENTERED EAST OF MICHIGAN AND A STRONG COLD FRONT NOW
MOVING INTO THRU THE UPPER MISSISSIPPI VALLEY. LONG LINE OF
STRONG/SVR CONVECTION REMAINS ALONG AND JUST AHEAD OF THE FRONT.
LEADING EDGE OF THIS CONVECTION IS STILL WELL WEST OF OUR CWA OVER
WRN WISCONSIN. LATEST NAM12...RAP13 AND HRRR ALL SUGGEST THAT THIS
CONVECTION WILL NOT REACH OUR CWA UNTIL AFTER 12...ACTUALLY MORE
TOWARD 15Z. DO EXPECT SOME INCREASE IN MID/HIGH CLOUDS FOR THE FAR
WRN SECTIONS OF OUR CWA OVERNIGHT AS ASSOCIATED CLOUD COVER
REMAINS CLOSE TO THE FRONT ITSELF.
&&
.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 328 PM EDT SAT AUG 22 2015
HIGH IMPACT WEATHER: NONE
OVERVIEW...THE MAIN CONCERN WITH THE FORECAST PACKAGE IS THE STORMS
SYSTEM WEST OF US. THE MAIN LOW IS CURRENTLY SOUTH OF LAKE WINNIPEG,
WITH A WARM FRONT THAT JUTS EAST, IN NW ONTARIO, AND A COLD FRONT
THAT STRETCHES SOUTH INTO EASTERN NORTH DAKOTA, TO A SFC LOW IN
SOUTH DAKOTA, THEN SOUTHWEST THROUGH NEBRASKA AND WEST BACK INTO THE
INTERMOUNTAIN WEST. AT 500 MB, THE TROUGH TO THE WEST, JUST BEHIND
THE SFC LOW, HAS AN AXIS THAT RUNS ALONG THE MONTANA/ND BOARDER AND
ANOTHER SHORTWAVE TROUGH MOVING THROUGH THE UPPER MISSISSIPPI
VALLEY.
OTHERWISE HIGH PRESSURE CENTERED OVER THE LOWER GREAT LAKES WITH THE
RETURN FLOW JUST GETTING INTO THE UPPER GREAT LAKES, AND WARMING THE
REGION AND PROVIDING THE MOISTURE.
TONIGHT...ISOLATED RAIN SHOWERS IN NE LOWER WILL CONTINUE UNTIL
ABOUT SUN DOWN, SINCE THE MAIN REASON IS FROM THE DIURNAL CU. AS
THESE DIMINISH, THE CLOUDS WILL BEGIN TO CLEAR OUT AS WELL PRODUCING
A MAINLY QUIET, CLEAR SKY, WITH A LIGHT WARM BREEZE OVERNIGHT.
TEMPERATURES DON`T LOOK LIKE THEY WILL FALL MUCH AS THE RETURN FLOW
CONTINUES PUMP WARM AIR INTO THE REGION. IT COULD ALSO HAPPEN THAT
THE TEMPERATURES FALL A BIT, AND FLAT LINE IN THE MID TO UPPER 60S
OVERNIGHT, BUT IT SEEMS THAT TEMPERATURES WILL FALL INTO THE LOWER
TO MID 60S FIRST. AFTER 09Z, WE SHOULD START TO SEE SOME HIGHER
CLOUDS ADVANCING INTO THE WESTERN COUNTIES AHEAD OF THE SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH COLD FRONT. THERE IS A SMALL CHANCE
THAT A SHOWER MAY RUN INTO MANISTEE OR FRANKFORT BETWEEN 09Z AND
12Z, BUT THINK THAT THE MOISTURE AND INSTABILITY LOOKS WEAK AT THIS
POINT, SO WILL KEEP IT TO THE WEST SIDE OF LAKE MICHIGAN.
&&
.SHORT TERM...(SUNDAY THROUGH TUESDAY)
ISSUED AT 328 PM EDT SAT AUG 22 2015
HIGH IMPACT WEATHER: STRONGER STORMS SUNDAY...WATERSPOUT POTENTIAL
MONDAY-MONDAY NIGHT.
PATTERN OVERVIEW/FORECAST: LONG WAVE TROUGH HAS SET UP SHOP ACROSS
WESTERN CANADA...DIPPING INTO THE NRN CONUS COURTESY OF TWO DISTINCT
WAVES ROTATING THROUGH THE LARGER SCALE MEAN TROUGH. ONE PRONOUNCED
WAVE IN THE GULF OF ALASKA DELIVERING ACTIVE WEATHER TO THE WEST
COAST OF CANADA. SECOND STRONG WAVE (AND OUR MORE IMMEDIATE CONCERN)
ADVANCING THROUGH THE NRN PLAINS/SOUTH-CENTRAL CANADA REGION. STRONG
UPPER JET STREAK IS DIGGING INTO THE BACKSIDE OF THE WAVE AS A WEDGE
OF SUBSTANTIALLY COLDER AIR DIVES THROUGH THE NRN ROCKIES AND
HEADING INTO THE NRN PLAINS (AND EVENTUALLY...US). CORRESPONDING
DEEPENING SFC LOW IS LOCATED OVER THE DAKOTAS AND ATTENDING COLD
FRONT STRETCHING BACK INTO THE ROCKIES.
NRN PLAINS WAVE IS FORECAST TO GO "NEGATIVE TILT" AND CARVE OUT A
RATHER IMPRESSIVE (AND PSEUDO-CUTOFF) CLOSED LOW OVER THE GREAT
LAKES HEADING INTO MONDAY. THIS WILL DELIVER A RATHER UNSEASONABLY
COLD POCKET OF AIR TO THE GREAT LAKES AND MIDWEST (SREF GUIDANCE
DELIVERS A CORE OF +2C TO +4C 850 MB AIR RIGHT OVER NRN MICHIGAN
MONDAY NIGHT INTO TUESDAY). HOWEVER...MEAN LONG WAVE TROUGH IS
FORECAST TO REMAIN LARGELY ACROSS WESTERN (OR NORTHWESTERN) NOAM
THROUGH THE UPCOMING WEEK...SUGGESTING OUR IMPENDING DIVE INTO EARLY
FALL-LIKE WEATHER WILL BE SHORT LIVED AND SHOULD EVENTUALLY
TRANSITION BACK OUT TO MORE SEASONABLE READINGS BY LATE IN THE WEEK.
SUNDAY...NEGATIVELY TILTED SHORT WAVE TROUGH AXIS WILL BE SWINGING
UP THROUGH THE WESTERN GREAT LAKES/NRN MICHIGAN THROUGH THE COURSE
OF THE DAY. PARENT OCCLUDING LOW PRESSURE CENTER ADVANCES SLOWLY
INTO ONTARIO WITH ATTENDING OCCLUDING/COLD FRONT SLIDING ACROSS THE
CWA...MAINLY DURING THE AFTERNOON PER CURRENT GUIDANCE TIMING. AHEAD
OF THE FRONT...NARROW AXIS OF MOISTURE/INSTABILITY WILL BE NOSING UP
THROUGH THE CWA AHEAD OF THE FRONT AND THERE SHOULD BE PLENTY OF
FORCING (UPPER LEVEL HEIGHT FALLS AND LOW LEVEL CONVERGENCE) TO
MARCH A TIGHT NARROW CORRIDOR OF SHOWERS AND THUNDERSTORMS ACROSS
THE CWA...LATE MORNING THROUGH THE AFTERNOON. HAVE ADDED SOME 3-
HOURLY TIMING DETAIL TO THE FORECAST FOR SUNDAY BUT OF COURSE THAT
IS SUBJECT TO CHANGE. BUT IN ESSENCE...ANTICIPATED SHOWERS/STORMS TO
IMPACT THE WESTERN HALF OF THE CWA THROUGH MIDDAY AND EASTERN HALF
DURING THE AFTERNOON INTO EARLY EVENING.
SEVERE WEATHER POTENTIAL...DECENT FORCING AND MODESTLY STRONGER
WINDS ALOFT/30-40 KNOTS 0-6KM BULK SHEAR COULD SUPPORT SOME STRONGER
UPDRAFTS PARTICULARLY DOWN TOWARD SAGINAW BAY INTO SRN LOWER
MICHIGAN. INSTABILITY IS NOT SO IMPRESSIVE HOWEVER...BUT GIVEN THE
STRONG DYNAMICS/KINEMATICS...CERTAINLY CANNOT RULE OUT A MARGINAL
SEVERE WEATHER THREAT TOMORROW AFTERNOON...ESPECIALLY ACROSS THE
S/SE PART OF THE CWA WHERE BEST INSTABILITY AND STRONGER SHEAR
WILL BE FOUND.
SUNDAY NIGHT-TUESDAY...SIMPLY STATED...TURNING FALL-LIKE WITH RAIN
SHOWERS. SORT OF A TRANSITION PERIOD SUNDAY NIGHT THROUGH EARLY
MONDAY AS COLD FRONT AND NARROW LINE OF SHOWERS/STORMS EXIT ACROSS
LAKE HURON EARLY SUNDAY EVENING...AND WE GET SOME SEMBLANCE OF A DRY
SLOT SLIPPING THROUGH THE REGION THROUGH MONDAY MORNING. CORE OF
COLDEST AIR ARRIVES MONDAY NIGHT...BUT INITIAL COLD ADVECTION BEHIND
THE FRONT DROPS LOW LEVEL TEMPS (H8) TO AROUND 7C SUNDAY NIGHT. AND
WITH SOME BETTER MOISTURE STARTING TO ROTATE THROUGH UPPER
MICHIGAN/NRN LAKE MICHIGAN...WILL PROBABLY SEE SOME LAKE
EFFECT/ENHANCED RAIN SHOWERS GET GOING AS EARLY AS SUNDAY NIGHT
THROUGH MONDAY MORNING.
BUT THE REALLY GOOD STUFF WILL RAMP UP LATER MONDAY AND MONDAY
NIGHT AS SECONDARY SFC TROUGH/COLD FRONT SWINGS THROUGH USHERING
IN EVEN COLDER AIR (<4C) AND (MORE IMPORTANTLY) SOME QG-FORCING
FOR ASCENT AND BETTER MOISTURE. LAKE EFFECT/HEATING INDUCED RAIN
SHOWERS SHOULD REALLY TAKE OFF MONDAY AFTERNOON AND PERSIST
THROUGH MONDAY NIGHT AS WELL AS MUCH OF TUESDAY. WILL CARRY SOME
HEFTY POPS ACROSS MUCH OF THE CWA THROUGH THAT TIME WITH AN
EMPHASIS ACROSS THE USUAL W-NW LAKE EFFECT AREAS. DON/T HAVE SMALL
HAIL/GRAUPEL MENTIONED JUST YET BECAUSE THE NEEDED INSTABILITY
JUST DOESN/T APPEAR TO BE THERE. BUT SOMETHING TO KEEP IN MIND AS
WELL.
TEMPS...STILL RELATIVELY WARM ON SUNDAY. COLDER AIR SPILLS IN SUNDAY
NIGHT AND WE THEN STRUGGLE IN THE 60S BOTH MONDAY AND TUESDAY FOR
MOST AREAS. TUESDAY IS THE "COLDEST" AND I WOULDN/T BE SURPRISED TO
SEE A FEW SPOTS (GAYLORD) NOT MAKE IT OUT OF THE 50S (HAVE UNDERCUT
ALL GUIDANCE MAX TEMPS FOR TUESDAY).
&&
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 328 PM EDT SAT AUG 22 2015
RAIN CHANCES WILL BEGIN TO DIMINISH FOR EASTERN PARTS OF THE STATE
TUESDAY NIGHT GOING INTO WEDNESDAY AS THE CUTOFF LOW OVER ONTARIO
LIFTS INTO QUEBEC. HOWEVER...WILL HAVE TO DIVERGE A BIT FROM BLENDED
MODEL GUIDANCE GOING INTO THURSDAY FOR WESTERN PORTIONS OF THE
STATE. WITH SUFFICIENT MOISTURE LOOKING TO STAY AROUND...AND H8
TEMPS REMAINING LOW ENOUGH FOR LAKE PROCESSES TO KICK IN...WILL ADD
CHANCE POPS FOR SOME POSSIBLE LAKE EFFECT SHOWERS TO STICK AROUND
THROUGH THURSDAY. WILL ALSO LEAVE CHANCE POPS OVER THE WEEKEND...AS
A QUICK MOVING SHORTWAVE DIVING THROUGH CANADA AND A COLD FRONT
ATTENDANT TO LOW PRESSURE NEAR HUDSON BAY TRANSITING THE AREA COULD
HELP TO KICK OFF SOME SHOWERS. AFTER A COUPLE OF COOL
DAYS...TEMPERATURES SHOULD MODERATE THROUGH THE EXTENDED PERIOD
GETTING BACK TO NEAR NORMAL FOR MOST AREAS BY SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 157 AM EDT SUN AUG 23 2015
...STORMS AND PERIODS OF MVFR ON THE WAY...
A WEDGE OF DRY AIR WILL WORK INTO THE REGION THROUGH DAYBREAK
KEEPING SKIES CLEAR. A COLD FRONT THEN PUSHES THROUGH NRN MICHIGAN
THROUGH THE DAY BRINGING A BAND OF SHOWERS AND STORMS...A FEW OF
WHICH MAY BE ABLE TO BECOME SEVERE WITH DAMAGING WINDS BEING THE
MAIN THREAT...SOME STRONGER CELLS COULD PRODUCE SOME HAIL. THIS
BAND ARRIVES NW LOWER MID TO LATE MORNING...AND ACROSS APN MID TO
LATE AFTERNOON. THE BAND OF SHOWERS AS WELL AS IN THE COOL AIR
BEHIND THE FRONT WILL BRING PERIODIC MVFR CIGS AND VSBYS. SUNDAY
NIGHT CONTINUED COOLING WILL BRING THE DEVELOPMENT OF LAKE EFFECT
RAIN SHOWERS TO PLN.
S/SW WINDS WILL BE GUSTY INITIALLY AHEAD OF THE FRONT...LONGEST
PERIOD OF GUSTINESS ACROSS APN. GUSTS MAY DISAPPEAR FOR AWHILE
WITHIN THE BAND OF RAIN...BUT WILL PICK UP AGAIN BEHIND THE FRONT
OUT OF THE W/NW. THIS GUSTY CONDITION WILL CONTINUE ACROSS NW
LOWER THROUGH SUNDAY NIGHT.
&&
.MARINE...
ISSUED AT 328 PM EDT SAT AUG 22 2015
TONIGHT THROUGH MONDAY...WINDS TONIGHT WILL BEGIN TO INCREASE
ESPECIALLY AFTER 06Z/SUN AS THE SFC HIGH MOVES EAST AND THE GRADIENT
TIGHTENS THROUGH THE NIGHT. BY SUNDAY MORNING (AROUND 12Z) THE WINDS
SHOULD BE HIGH ENOUGH ALONG THE LAKE MICHIGAN AND SHORE AND IN
WHITEFISH BAY FOR SMALL CRAFT ADVISORIES. WITH THE COLD FRONT MOVING
ACROSS THE LAKE SUNDAY MORNING, AND THEN ACROSS NORTHERN MICHIGAN
DURING THE DAY, WILL EXPECT THAT LAKE HURON WILL GET IN ON THE ACT,
SO SMALL CRAFT ADVISORIES WILL BE ADDED FOR THERE AS WELL. THE
ADVISORIES WILL CONTINUE INTO THE NIGHT POST-FRONTAL, ALTHOUGH WITH
THE SFC LOW MOVING OVER LAKE SUPERIOR, THE GRADIENT WILL SLACKEN SO
THE SMALL CRAFT WON`T BE NEEDED FOR WHITEFISH BAY AND THE ST. MARY`S
RIVER. IT LOOKS LIKE WE WILL PROBABLY NEED TO CONTINUE THE
ADVISORIES INTO MONDAY AS THE GRADIENT STILL LOOKS FAIRLY TIGHT OVER
N LOWER.
IN ADDITION TO THE GUSTY WINDS/HIGHER WAVES...AN UNSEASONABLY COLD
AIRMASS WILL SLIP ACROSS THE GREAT LAKES MONDAY THROUGH
TUESDAY...DELIVERING WIDESPREAD LAKE EFFECT RAIN SHOWERS.
WATERSPOUTS WILL ALSO BE A POSSIBILITY WITH THE BEST TIMEFRAME
LOOKING TO BE MONDAY AFTERNOON THROUGH MONDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EDT MONDAY
FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 6 AM EDT MONDAY
FOR LMZ323-341-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO MIDNIGHT EDT
TONIGHT FOR LSZ321-322.
&&
$$
UPDATE...MLR
NEAR TERM...JSL
SHORT TERM...ADAM
LONG TERM...ALM
AVIATION...SMD
MARINE...ADAM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
119 AM CDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 119 AM CDT SUN AUG 23 2015
WINDS CONTINUE TO SLOWLY DIMINISH IN WESTERN PARTS OF THE
STATE...WHILE THE STRONGER WINDS HAVE NOW REACHED AREAS FROM THE
TURTLE MOUNTAINS TO THE JAMES RIVER VALLEY. ALLOWED THE WIND
HEADLINES TO EXPIRE IN MUCH OF THE WEST AND CENTRAL...BUT OPTED
TO HOLD ONTO THE WIND ADVISORY INTO SUNDAY AFTERNOON IN OUR EAST.
MOMENTUM TRANSFER FROM BUFR SOUNDINGS SUGGEST WINDS WILL CONTINUE
AT ADVISORY LEVELS FROM THE TURTLE MOUNTAINS THROUGH THE JAMES
RIVER VALLEY INTO SUNDAY AFTERNOON. THERE COULD BE A BRIEF
DECREASE IN WINDS TOWARDS SUNRISE...BUT WINDS SHOULD PICK UP AGAIN
AS MIXING INCREASES. THIS LINES UP WELL WITH THE CURRENT HEADLINE
IN PLACE FROM FGF.
BLENDED IN CURRENT CONDITIONS AND RAN A TIME LAGGED ENSEMBLE OF
THE HRRR FOR POPS. THIS CONTINUES A GRADUAL DECREASE IN
PRECIPITATION CHANCES FROM WEST TO EAST EARLY THIS MORNING.
UPDATE ISSUED AT 1008 PM CDT SAT AUG 22 2015
QUICK UPDATE TO EXPIRE THE WIND HAZARDS IN THE WEST. ALSO UPDATED
POPS BASED ON LATEST RADAR TRENDS.
UPDATE ISSUED AT 833 PM CDT SAT AUG 22 2015
CURRENTLY...UPPER LEVEL LOW IS SITUATED BETWEEN BISMARCK AND
JAMESTOWN...WITH THE SURFACE LOW WELL TO THE EAST. STRONG PRESSURE
RISES OVER WESTERN MINNESOTA BEHIND THE SURFACE FRONT...AND ALSO
OVER NORTHWEST NORTH DAKOTA BEHIND THE UPPER LEVEL LOW. A SMALL
AREA OF PRESSURE FALLS ASSOCIATED WITH THE UPPER LOW CURRENTLY
RESIDE OVER SOUTH CENTRAL NORTH DAKOTA INTO THE JAMES RIVER
VALLEY. THINK ONCE THIS TRACKS OFF TO THE EAST...WE WILL STILL
SEE SOME STRONG WINDS ACROSS CENTRAL NORTH DAKOTA LATE THIS
EVENING. WILL THEY BE HWW CRITERIA? PROBABLY NOT WITH GUSTS BUT
THINK WE COULD STILL SEE SOME SUSTAINED WINDS AROUND TO 40 MPH.
CURRENT HWW FOR THE SOUTHWEST AND SOUTH CENTRAL EXPIRES AT 10 PM.
THINK ITS SAFE TO LET THE HWW EXPIRE AT 10 ACROSS THE
SOUTHWEST...THIS IS WHEN THE WIND ADVISORY ALSO EXPIRES IN THE
NORTHWEST. COULD EXPIRE THE HWW IN THE SOUTH CENTRAL AND REPLACE
IT WITH A WIND ADVISORY. BUT WHAT WE WILL DO IS EXTEND THE HWW IN
THE SOUTH CENTRAL THROUGH 06Z (1 AM CDT). THINK THE POTENTIAL IS
STILL THERE FOR SOME STRONG WINDS...PLUS THINK THIS WOULD CUT
SOME OF THE CONFUSION OF EXPIRING ONE HAZARD AND ISSUING ANOTHER.
FARTHER TO THE EAST...WILL ALSO EXTEND THE WIND ADVISORY IN THE
EAST THROUGH 09Z (4 AM CDT).
HAVE ADJUSTED POPS BASED ON LATEST ITERATIONS OF THE RAP/HRRR.
THIS LINES UP WELL WITH CURRENT TRENDS. IT WOULD ALSO END
PRECIPITATION IN THE TURTLE MOUNTAINS AND JAMES RIVER BASIN A FEW
HOURS EARLIER THAN PREVIOUSLY FORECAST. ALL IN ALL...A WET AND
WINDY FORECAST ACROSS CENTRAL NORTH DAKOTA. HOWEVER...THE RAIN HAS
ENDED IN THE FAR WEST AND WINDS ARE STARTING TO DIMINISH.
UPDATE ISSUED AT 644 PM CDT SAT AUG 22 2015
SURFACE LOW PRESSURE IN NORTHERN MINNESOTA WITH UPPER LEVEL LOW
TRACKING THROUGH CENTRAL NORTH DAKOTA. MAIN UPDATE WAS TO ADJUST
POPS BASED ON CURRENT RADAR AND EXTRAPOLATION. CURRENTLY A PRETTY
LARGE DRY SLOT OVER CENTRAL AND EASTERN NORTH DAKOTA.
HOWEVER...MOISTURE ASSOCIATED WITH THE UPPER LOW OVER WESTERN
NORTH DAKOTA IS JUST MAKING ITS WAY TO THE HIGHWAY 83 CORRIDOR AND
WILL CONTINUE TO TRACK EASTWARD THIS EVENING. WINDS REMAIN STRONG
WITH THE TIGHT PRESSURE GRADIENT. THE UPPER LOW IS PRODUCING SOME
PRESSURE FALLS OVER CENTRAL NORTH DAKOTA WHICH IS HINDERING THE
STRONGER WINDS...BUT AS THE LOW MOVES EAST...ADDITIONAL PRESSURE
RISES ARE POISED TO MOVE INTO CENTRAL NORTH DAKOTA. THUS EXPECT
WINDS TO REMAIN STRONG OR EVEN PICK UP ACROSS CENTRAL NORTH DAKOTA
THIS EVENING. NO CHANGES TO THE CURRENT HAZARDS. PNS WAS SENT
EARLIER WITH HIGHEST GUSTS THROUGH 5 PM CDT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 333 PM CDT SAT AUG 22 2015
WILL UPGRADE THE WIND ADVISORY TO A HIGH WIND WARNING SOUTH
CENTRAL FOR THE REST OF THE AFTERNOON AND THIS EVENING. MODEL
SOUNDINGS SHOW THE BEST MOMENTUM TRANSFER WILL BEGIN LATE THIS
AFTERNOON AND THIS EVENING SOUTH CENTRAL. WITH THE DRY SLOT
SHOWING UP IN SAT IMAGES FEEL THIS WILL BE REALIZED MAINLY EARL
THIS EVENING SOUTH CENTRAL. OTHERWISE REMAINDER OF THE ADVISORY
REMAINS IN EFFECT FOR THIS EVENING NORTH THROUGH THE EAST.
ON SUNDAY...WINDS WILL BE GREATLY DIMINISHED AND SKIES WILL BE
CLEARING.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 333 PM CDT SAT AUG 22 2015
THE STRONG LOW PRESSURE SYSTEM ASSOCIATED WITH THE WINDY AND SHOWERY
DAY SATURDAY AND SATURDAY NIGHT...WITH WINDS CONTINUING
SUNDAY...WILL BE EXITING THE REGION. THEN A WESTERN RIDGE BUILDS
BRINGING SEASONABLE AUGUST WEATHER TO OUR AREA THROUGH THE UPCOMING
WEEK.
SUNDAY EVENING THE STRONG LOW PRESSURE SYSTEM IS FORECAST TO BE
CENTERED OVER SOUTHWESTERN ONTARIO...WITH HIGH PRESSURE SETTLING
OVER THE DAKOTAS THROUGH THE NIGHT. LIGHT WINDS AND CLEAR SKIES WILL
ALLOW TEMPERATURES TO DROP INTO THE 40S ACROSS MUCH OF WESTERN AND
CENTRAL NORTH DAKOTA...WITH A FEW AREAS POSSIBLY DIPPING INTO THE
UPPER 30S.
THE BUILDING WESTERN RIDGE WILL BRING A WARMING TREND...WITH HIGHS
MONDAY FROM 70 TO 80...TO 80 TO 90 BY THURSDAY. ON THURSDAY AND
FRIDAY THERE IS A CHANCE OF THUNDERSTORMS WITH SOME UPPER LEVEL
ENERGY IMPULSES MOVING THROUGH THE RIDGE ACROSS THE CENTRAL
ROCKIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 119 AM CDT SUN AUG 23 2015
CONDITIONS SHOULD CONTINUE TO IMPROVE FROM WEST TO EAST EARLY THIS
SUNDAY MORNING. SHOWERS WITH REDUCED VISIBILITIES WILL CONTINUE AT
KJMS FOR ANOTHER COUPLE HOURS...WITH VFR CONDITIONS THEN EXPECTED.
WINDS SHOULD REMAIN GUSTY THROUGH SUNDAY AFTERNOON...BUT WILL
DIMINISH SUNDAY EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR NDZ005-013-023-
025-036-037-047-048-050-051.
&&
$$
UPDATE...CK
SHORT TERM...WAA
LONG TERM...JV
AVIATION...CK
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1137 PM CDT SAT AUG 22 2015
.AVIATION...
/06Z TAFS/
CONCERNS: NONE. HAVE REMOVED MVFR CIGS AT WACO AFTER 12Z SUNDAY AS
IT APPEARS BOUNDARY LAYER FLOW IS TOO WEAK AND LAYER IS TOO DRY
FOR STRATUS IN THE MORNING. OTHERWISE...VFR WITH S-SE FLOW 10-15
KTS THROUGHOUT.
AS FOR POSSIBLE WEAK COLD FROPA...MODELS DISAGREE QUITE A BIT WITH
THE GFS WAY FASTER THAN THE ECMWF OR NAM MOS GUIDANCE. BEING THERE
THE FRONT WILL LOST UPPER SUPPORT AND STRONG AUGUST HEATING...HAVE
OPTED FOR THE LATTER TWO GUIDANCES WHICH IS WELL BEYOND THE 30 HR
PERIOD FOR DFW. CONVECTIVE CHANCES 24 HOURS WILL BE TOO ISOLATED
AND SHOULD REMAIN CLOSER TO THE RED RIVER VALLEY FOR ANY MENTION
AT DFW AIRPORTS.
05/
&&
.UPDATE...
THE OUTFLOW BOUNDARY ALONG THE EASTERN RED RIVER COUNTIES HAS
DISSIPATED AND WINDS HAVE RETURNED TO THE SOUTH. ALL HI-RES
MODELS DO NOT SHOW ANY CONVECTION IN THE CWA OVERNIGHT AND HAVE
REMOVED POPS AREA WIDE.
TTU WRF AND HRRR MODELS DO NOT BRING THE FRONT SOUTH OF THE RED
RIVER UNTIL LATE SUNDAY AFTERNOON. THUS WE HAVE LOWERED POPS
TO 20 PERCENT SUNDAY MORNING ALONG THE RED RIVER VALLEY...AND
20-30 PERCENT SUNDAY AFTERNOON ALONG AND NORTH OF I-20. THE MOST
FAVORED AREA FOR CONVECTION SUNDAY AFTERNOON AND EVENING SHOULD BE
THOSE COUNTIES EAST OF A GAINESVILLE TO DENTON LINE. 75
&&
.PREV DISCUSSION... /ISSUED 324 PM CDT SAT AUG 22 2015/
A COMPLEX OF THUNDERSTORMS ASSOCIATED WITH A SHORT WAVE WILL
CONTINUE MOVING ACROSS EXTREME EASTERN OKLAHOMA AND ARKANSAS
THIS AFTERNOON. SOME OF THESE STORMS WILL MOVE SOUTHEAST OF THE
MAIN COMPLEX ON AN OUTFLOW BOUNDARY AND AFFECT THE NORTHEAST ZONES
THROUGH LATE AFTERNOON.
A FEW SHOWERS AND THUNDERSTORMS ARE ALSO POSSIBLE ACROSS THE
SOUTHEAST ZONES OF NORTH TEXAS THROUGH SUNSET WHERE MOISTURE AND
INSTABILITY ARE THE MOST ABUNDANT. THIS ACTIVITY SHOULD DISSIPATE
WITH THE LOSS OF SURFACE HEATING.
AFTER SUNSET...A QUIET...WARM AND HUMID NIGHT IS STORE WITH
OVERNIGHT LOWS FROM THE MID 70S TO AROUND 80.
A COLD FRONT WILL MOVE ACROSS THE CENTRAL PLAINS OVERNIGHT AND
SUNDAY MORNING AND REACH THE RED RIVER AROUND MIDDAY. WEAK
FORCING FOR ASCENT MAY RESULT IN A FEW SHOWERS AND THUNDERSTORMS
ACROSS THE NORTHERN HALF OF NORTH TEXAS SUNDAY AFTERNOON/SUNDAY
NIGHT. HOWEVER...WEAK LARGE SCALE SUBSIDENCE MAY LIMIT OR EVEN
PREVENT STORMS FROM FORMING. THEREFORE...WE WILL KEEP ONLY 20 TO
30 PERCENT POPS IN THE FORECAST.
THE COLD FRONT WILL MOVE SLOWLY THROUGH NORTH TEXAS MONDAY THROUGH
TUESDAY AND WILL WARRANT THE MENTION OF SOME LOW POPS. THE FRONT
WILL ALSO BRING A FEW MORE CLOUDS BUT ONLY SLIGHTLY COOLER
TEMPERATURES.
UPPER LEVEL HIGH PRESSURE WILL REMAIN CENTERED OVER ARIZONA AND
NEW MEXICO WEDNESDAY THROUGH THE WEEKEND WHICH WILL KEEP NORTH
TEXAS IN DRY NORTH TO NORTHWEST FLOW ALOFT. THE EXTENDED MODELS
HAVE BEEN ADVERTISING A WEAK SHORT WAVE ON THE NORTHEASTERN
PERIPHERY OF THE UPPER RIDGE APPROACHING THE RED RIVER ON FRIDAY.
HOWEVER...MOISTURE SHOULD BE VERY LIMITED WHEN THE SHORT WAVE
ARRIVES AND PRECIPITATION SEEMS UNLIKELY AT THIS TIME.
SEASONABLY WARM TEMPERATURES ARE EXPECTED WEDNESDAY THROUGH THE
WEEKEND WITH HIGHS IN THE LOWER AND MIDDLE 90S AND LOWS IN THE
70S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 98 75 95 74 / 5 20 20 20 20
WACO, TX 78 99 77 99 74 / 5 5 5 20 20
PARIS, TX 74 95 72 91 69 / 10 30 40 20 20
DENTON, TX 78 97 70 92 71 / 5 20 30 20 20
MCKINNEY, TX 77 97 73 93 69 / 5 30 30 20 20
DALLAS, TX 80 99 77 96 76 / 5 20 20 20 20
TERRELL, TX 78 99 73 97 71 / 5 20 20 20 20
CORSICANA, TX 78 98 76 99 75 / 5 10 10 20 20
TEMPLE, TX 76 98 76 99 75 / 0 5 5 20 10
MINERAL WELLS, TX 74 99 71 94 70 / 5 10 20 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/75
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1133 PM CDT SAT AUG 22 2015
.AVIATION...
/06Z TAFS/
Low to mid 70s dew points in the Hill Country were advecting
northward toward the I-10 corridor at 5Z, and expect to see
stratus with MVFR ceilings at KSOA and KJCT for 2-3 hours after
sunrise. An isolated shower or thunderstorm possible a weak cold
front approaches KABI late Sunday evening, but the best potential
will be Monday. Will not include VCTS at KABI due to sparse
thunderstorm coverage.
&&
.PREV DISCUSSION... /ISSUED 641 PM CDT SAT AUG 22 2015/
AVIATION...
/00Z TAFS/
MVFR stratus likely along the I-20 corridor, affecting KSOA and
KJCT late tonight through mid morning Sunday. Otherwise VFR with
southeast to south winds 12 KTs or less.
PREV DISCUSSION... /ISSUED 318 PM CDT SAT AUG 22 2015/
SHORT TERM...
(Tonight and Sunday)
A few diurnal thunderstorms have developed over the Davis Mountains
this afternoon with only sparse cu field and a few high clouds over
West Central TX. Temperatures have warmed into the mid/upper 90s
with dewpoints holding in the low/mid 60s. Generally quiet weather
conditions are expected tonight across the area with the cu field
dissipating with the setting sun. The HRRR has been insistent on
developing some convection west of San Angelo late this afternoon,
but this solution has been dismissed as an outlier, especially given
the lack of a focused cu field this afternoon. Tonight, expect
temperatures to drop into the mid 70s with southerly winds remaining
in the 6-12 mph range. Winds could become gusty for a few hours
tonight, especially in the higher terrain as the low-level jet sets
up.
A weak cold front will move south into the Big Country on Sunday.
The general consensus is that this front will move as far south as a
Sterling City to Eastland line by early afternoon, likely stalling
out for the remainder of the day. Temperatures are expected to be a
few degrees cooler (low/mid 90s) behind this boundary, with highs
likely in the mid/upper 90s to the south. Scattered showers and
thunderstorms are expected to develop during the afternoon in the
vicinity of this cold front. While organized severe weather is not
anticipated, high cloud bases will yield a potential microburst
environment.
Johnson
LONG TERM...
(Sunday night through Saturday)
A weak cold front will be located across the Big Country Sunday
evening, then slowly move south. Along and behind the front,
isolated to scattered showers will be possible, with the best chance
north of Interstate 20. The front will slowly progress south
reaching the Concho Valley/Heartland Monday morning. The front will
serve as the focus for additional isolated showers and thunderstorms
on Monday, mainly north of a Mertzon, to Menard, to Mason line.
Much of the rest of the extended forecast will be characterized by
an upper level ridge centered over the Desert Southwest, with West
Central Texas in northwest to north flow aloft. The forecast
generally looks to remain dry, but given the northerly flow aloft,
any embedded upper level shortwave troughs (disturbances) could
result in at least isolated convection for portions of the area. The
first opportunity for showers and thunderstorms will be Tuesday as
disturbance in the northwest flow aloft traverses the area. This is
depicted most aggressively by the ECMWF, with the best PoPs across
the eastern half of the area. The next opportunity for rainfall will
be Friday into next weekend, as another cold front approaches the
area. The best PoPs look to be across the Big Country at this time.
In conclusion, the timing and strength of any disturbances is hard
to pinpoint this far in advance, but the overall theme for the
upcoming week is for dry conditions to persist.
Temperatures through much of the upcoming work week will be above
normal. Highs will generally be in the mid to upper 90s, although a
few locations may approach the century mark, especially during the
first part of the week. Overnight lows will generally be in the 70s,
with a few locations dropping into the upper 60s.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 76 97 73 94 / 5 20 30 20
San Angelo 76 101 74 98 / 5 10 10 20
Junction 75 99 74 98 / 5 5 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
301 AM CDT SUN AUG 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT SUN AUG 23 2015
MOST OF THE FORECAST SHIFT WAS SPENT TRYING TO BUILD IN DETAILS ON
THE TRENDS IN THE WEATHER FROM THE STRONG CYCLONE OVER THE
NORTHERN PART OF THE REGION. OVERALL...DIDNT GET THE STRENGTH OF
STORMS OUT OF THE SYSTEM...AND MARGINAL WIND SHEAR AT BEST AND
THIN INSTABILITY TONGUE HAD MUCH TO DO WITH THAT.
GOES WATER VAPOR SHOWING THE VIGOROUS SHORTWAVE TROUGH EJECTING
E-NE TOWARD KDLH AT 07Z WITH DEFORMATION PRECIPITATION SEEN ACROSS
ND IN REGIONAL RADARS. LOCALLY...THE COLD FRONT IS PUSHING TOWARD
ERN WI WITH LIGHT SHRA AHEAD OF THE FRONT AND SOME POST-FRONTAL
SHRA ABOUT A COUNTY FURTHER WEST. MULTIPLE FRONTOGENETIC BANDS
INDICATED IN THE RAP IN THE LOWER LEVELS. THESE WILL CONTINUE EAST
AND OUT OF THE FORECAST AREA DURING THE EARLY MORNING HOURS.
CLOUDS AND LOW-LEVEL SECONDARY TROUGH/FRONTAL AXIS ALONG
MN/DAKOTAS BORDER IS SHIFTING TOWARD THE AREA AS WELL. AS THE
SURFACE LOW SHIFTS EAST THROUGH SOUTHERN MANITOBA TODAY AND
FILLS...MANY OF THE FORCING FEATURES WEAKEN...INCLUDING THE
MN TROUGH AXIS AND CONVERGENCE ALONG IT. THE SYSTEM BECOMES A
BROAD CYCLONIC FLOW SCENARIO WITH ONLY A WEAK REMNANT TROUGH
AFFECTING NRN WI LATER THIS MORNING AND AFTERNOON. HAVE BROUGHT
SOME ISO-SCT SHRA BACK IN ALONG AND NORTH OF I-94 FOR MAINLY THE
17-22Z WINDOW. THERE IS SOME SUGGESTION IN THE HI-RES MODELS THAT
THIS COULD ALSO AFFECT CENTRAL WI. HAVE ALSO CONTINUED AFTERNOON
WIND GUSTS OF 25-35 MPH...REMAINING BELOW WIND ADVISORY CRITERIA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN AUG 23 2015
CONFIDENCE IS ABOVE AVERAGE THROUGH THURSDAY WITH QUIET WEATHER
EXPECTED AND BELOW NORMAL TEMPERATURES. ALONG AND NORTH OF I-94
TEMPERATURES WILL BE MUCH BELOW NORMAL. MONDAY WILL BE THE
COLDEST DAY BEFORE MODERATION SLOWLY OCCURS...ESPECIALLY WEDNESDAY
ON. HAVE LOWERED THE TEMPERATURES IN THE NORTH DOWN A NOTCH INTO
THE UPPER 50S FOR HIGHS MONDAY AS THE COLD AIR POCKET SLIPS
THROUGH UNDER THICK CLOUDS.
ON MONDAY..MAY HAVE TO TREND TOWARD HIGHER SHRA CHANCES NORTHEAST OF
I-94 MONDAY AFTERNOON DEPENDING ON THE TRACK OF WELL AGREED UPON
SHORTWAVE TROUGH ENERGY. THIS WAVE IS ACTUALLY THE CURRENT MN
VORTEX ROTATING AROUND THE LONGER WAVE TROUGH AND BACK IN FROM THE
NORTH MONDAY. CURRENTLY THE TRACK APPEARS TO FAVOR NORTHEASTERN WI
FOR SHRA...BUT WILL KEEP WATCH AS DIURNAL TIMING IS IDEAL FOR
ENHANCED SHRA COVERAGE. MONDAY AGAIN WILL SEE GUSTY NORTHWEST
WINDS OF 25-30 MPH IN THE AFTERNOON.
RIDGE BUILDING THEN BEGINS AND DOMINATES THROUGH THURSDAY.
SOME DIFFERENCES SHOW UP FRIDAY AND INTO SATURDAY. SOME RETURN
FLOW WARMING OCCURS AND THE GFS IS MORE AGGRESSIVE WITH RIDGE
BUILDING OVER THE NORTHERN CONUS. THE 23.00Z CANADIAN/ECMWF AND
21.18Z DGEX SOLUTIONS ARE AT ODDS WITH THE 23.00Z GFS...AS THEY
ALL HAVE A CUTOFF LOW DRIFTING E/SE THROUGH NEB/IA LATE IN THE
WEEK. HOWEVER...THE 23.00Z GEFS DOES HAVE SOME MEMBERS THAT PICK
UP ON THE LOW AS WELL...SO IT LOOKS LIKE THAT MAY BE A BETTER
SOLUTION FOR LATE WEEK. THIS WOULD BRING SOME RAIN CHANCES
POSSIBLY CLOSE OR INTO THE AREA. WILL HAVE TO LET THIS ALL SHAKE
OUT...AND WENT WITH CONSENSUS BLEND WHICH TURNS INTO SLIGHT
CHANCES FOR RAIN AND HIGHS RETURNING TO NEAR NORMAL BY SATURDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1137 PM CDT SAT AUG 22 2015
MAINLY MVFR TO VFR CONDITIONS AS COLD FRONT PUSHES THROUGH AREA
OVERNIGHT. AREA OF SHOWERS AND THUNDERSTORMS ALONG AND BEHIND FRONT
HAS GENERATED SOME LOCALIZED IFR CONDITIONS...BUT THIS ENTIRE AREA
WILL SWING THROUGH THE NEXT FEW HOURS. THERE WILL BE A BRIEF DRY
SLOT TO CONTEND WITH...BUT THEN SOME CLOUDS TO DEAL WITH ON BACK
SIDE OF SHORT WAVE AS IT CONTINUES EAST. HAVE ATTEMPTED TO TIME THIS
INTO TAF SITES BUT NOT OVERLY CONFIDENT HOW FAR SOUTH CLOUD SHIELD
WILL GET OR LAST.
STRONG WEST TO NORTHWEST WINDS ON BACK SIDE OF SYSTEM AS WELL ON
SUNDAY...BUT SKIES SHOULD CLEAR AND WINDS SHOULD SUBSIDE HEADING
INTO SUNDAY EVENING LEADING UP TO AN EXTENDED PERIOD OF VFR WEATHER
IT APPEARS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...SHEA
AREA FORECAST DISCUSSION...CORRECTED
NWS PHOENIX AZ
455 AM MST SUN AUG 23 2015
.SYNOPSIS...
HIGH PRESSURE WILL BECOME REESTABLISHED TO OUR EAST...RESULTING IN
HIGHER THAN NORMAL RAIN CHANCES ACROSS THE LOWER DESERTS THROUGH
TUESDAY. DRIER CONDITIONS WILL RETURN BY MIDWEEK ALONG WITH ABOVE
NORMAL TEMPERATURES. WELL ABOVE NORMAL TEMPERATURES ARE POSSIBLE BY
NEXT WEEKEND.
&&
.DISCUSSION...
LATEST RAP STREAMLINE ANALYSIS SHOWS THE SUBTROPICAL RIDGE WEAKENING
ACROSS THE BAJA PENINSULA AND MIGRATING EASTWARD...RESULTING IN A
CESSATION OF THE PERSISTENT WESTERLY FLOW. A VERY WEAK STEERING FLOW
WILL DEVELOP TODAY FOLLOWED BY A REVERSAL IN THE WINDS TO LIGHT
EASTERLY BY TONIGHT. MEANWHILE...A VORT MAX ASSOCIATED WITH AN
INVERTED TROUGH IS EVIDENT NEAR THE BOOTHEEL OF NM. THIS SETUP IS
FAVORABLE FOR THUNDERSTORM ACTIVITY ACROSS EASTERN AND SOUTHEASTERN
AZ TODAY WITH PROPAGATION TO THE WEST INTO SOUTH-CENTRAL AZ THIS
EVENING.
CONVECTIVELY PARAMETERIZED MODELS SUCH AS THE GFS...ECMWF AND NMM-B
SUGGEST SOME POTENTIAL FOR THUNDERSTORMS ACROSS THE LOWER DESERTS
INCLUDING THE PHOENIX AREA. HOWEVER...CONSENSUS AMONG THE CONVECTIVE
ALLOWING WRFS IS THAT CONVERGING OUTFLOW BOUNDARIES WILL PRODUCE ONLY
ISOLATED CONVECTION ACROSS THE PHOENIX AREA...BUT WITH PERHAPS HIGHER
PROBABILITIES ACROSS THE SOUTHWEST DESERTS. MOST LIKELY IMPACT
TONIGHT IS BLOWING DUST...THOUGH THE POTENTIAL CERTAINLY EXISTS FOR
THUNDERSTORMS CONTAINING STRONG WINDS AND DOWNBURSTS...PARTICULARLY
ACROSS PORTIONS OF MARICOPA AND PINAL COUNTIES. WITH THE INVERTED
TROUGH DRAPED ACROSS THE LOWER DESERTS OVERNIGHT...CONVECTION ALSO
CANNOT BE RULED OUT THROUGH MONDAY MORNING.
BEST CHANCE FOR PRECIPITATION APPEARS TO BE MONDAY AS THE MONSOON
HIGH DRIFTS TOWARDS THE FOUR CORNERS RESULTING IN A MOIST
SOUTHEASTERLY FLOW. MODELS ALSO INDICATE THAT THE 250 MB HIGH
DISPLACED TO THE SOUTH WILL PRODUCE A DIFLUENT AND DIVERGENT
PATTERN IN THE UPPER LEVELS...HELPING TO PROVIDE ASCENT WHICH MAY
OFFSET ANY LACK OF INSTABILITY DUE TO THE WIDESPREAD CLOUDINESS.
THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL PERSIST TUESDAY BUT
WILL SHIFT SOMEWHAT TO THE WEST. LATEST MODELS SUGGEST THAT SEVERAL
TRAILING VORT MAXES AND MCVS WILL PROVIDE ASCENT IN A RELATIVELY
STRONG AND MOIST SOUTHERLY FLOW. THE FOCUS FOR PRECIPITATION WILL
SHIFT NORTHWARD WEDNESDAY AS THE AFOREMENTIONED TROUGH ACCELERATES
NORTHEASTWARD AROUND THE ANTICYCLONE IN NM.
GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE RIDGE WILL AGAIN MIGRATE TO
OUR SOUTH LATE IN THE WEEK...RESULTING IN A SOUTHWESTERLY FLOW AND A
RETURN TO WARMER AND DRIER CONDITIONS. ABOVE NORMAL TEMPERATURES ARE
LIKELY BEGINNING THURSDAY WITH HIGHS IN THE PHOENIX AREA POTENTIALLY
REACHING 110 DEGREES AGAIN BY NEXT SATURDAY...AND EVEN WARMER ACROSS
SOUTHEASTERN CA. THIS COULD BE THE WARMEST AUGUST ON RECORD FOR BOTH
PHOENIX AND YUMA AND THE PERIOD OF ABOVE NORMAL TEMPERATURES TO END
THE MONTH MAY HELP CLINCH THE TOP SPOT FOR BOTH LOCATIONS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
MOSTLY CLEAR SKIES AND TYPICAL AM EASTERLY WINDS TO PERSIST THRU
MIDDAY. WINDS TO GRADUALLY SWING AROUND TO W-SW PSBLY AN HOUR OR TWO
EARLIER THAN THEIR USUAL EARLY AFTN WINDOW...PSBLY AS EARLY AS
23/18Z. TODAY BEGINS A SEVERAL-DAY RETURN PERIOD OF MORE FAVORABLE
MONSOON STORM CHANCES ACROSS THE LOWER DESERTS AND SURVIVING INTO
CORNERS OF THE PHX METRO TO START. HI-RES MODEL GUIDANCE AND EARLY
AM CCFP INDICATE STORMS TO DEVELOP FIRST ALONG THE MOGOLLON RIM BY
MIDDAY AND AN HOUR OR TWO LATER ACROSS SE AZ.
INITIAL BEST GUESS AT TIMING THE FIRST...IN A POTENTIAL FEW...OUTFLOW
INTRUSION...COULD BE BETWEEN THE 24/00-02Z WINDOW FROM EAST-
NORTHEAST. ADDITIONAL OUTFLOW PUSH FROM THE SOUTH COULD EXPAND INTO
THE PHX METRO POST 02Z...ALONG WITH ISO. POP-UP SHOWER AND STORM
ACTIVITY WITH ITS PASSAGE. GNLY OPENED WITH VCSH AROUND 24/02-03Z
TIMEFRAME FOR THE TERMINALS. VSBY REDUCTION IS PSBL EITHER IN
SUSPENDED/LOFTED DUST OR A MORE CONSOLIDATED OUTFLOW AND THICKER
DUST...BUT HELD OFF FROM INCLUDING VSBY REDUCTION IN THE 12Z TAF
PACKAGE ATTM. DEPENDING ON WHERE THE OUTFLOW ORIGINATES WILL HAVE
BEARING ON WHAT AMOUNT...IF ANY...DUST IT MANAGES TO PICK UP.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES AND PERSISTENT SOUTH TO SOUTHEASTERLY WINDS
FORECAST FOR THE WESTERN TERMINALS TODAY AND THIS EVENING. STORM
ACTIVITY SHOULD STAY WILL TO THE EAST ACROSS AZ THIS
AFTN/EVENING...WITH SOME PSBL HIGH LEVEL DEBRIS CLOUD IN LATER INTO
THE OVERNIGHT FOR KBLH.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MONSOON MOISTURE LEVELS AND HUMIDITIES WILL PERSIST TUESDAY AND
WEDNESDAY AS A SERIES OF UPPER LEVEL DISTURBANCES MOVE IN FROM THE
SOUTHEAST. THESE DISTURBANCES WILL SUPPORT ELEVATED CHANCES FOR MORE
WIDESPREAD AND SUBSTANTIAL STORM DEVELOPMENT REGION-WIDE...WITH
STORM CHANCES REACHING BEYOND THE CO RIVER VALLEY. MIN RH VALUES
WILL GENERALLY RANGE BETWEEN 20 TO 30 PERCENT WITH GOOD OVERNIGHT
RECOVERY. OUTSIDE OF THUNDERSTORM OUTFLOW AND VICINITY WINDS...SFC
WINDS WILL BEGIN TO FOLLOW TYPICAL DIURNAL/DRAINAGE DRIVEN TRENDS. A
DRAW DOWN OF MONSOON MOISTURE IS STILL FORECAST TOWARDS THE END OF
THE WEEK...BUT MAY OCCUR AT A SLOWER RATE THAN ORIGINALLY THOUGHT.
THE UPPER RIDGE WILL GRADUALLY POSITION ITSELF TO DRAW IN DRIER
WESTERLY FLOW ALOFT...RELEGATING STORM CHANCES BACK ACROSS THE
EASTERN AZ AND THE HIGHER TERRAIN. AS THE AIRMASS SLOWLY DRIES
OUT...DAYTIME TEMPERATURES WILL RISE TO ABOVE NORMAL VALUES AND IN
SOME OF THE SOUTHEAST CA FIRE ZONES PUSH THE 110F MARK BY THE
WEEKEND.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
313 AM MST SUN AUG 23 2015
.SYNOPSIS...
HIGH PRESSURE WILL BECOME REESTABLISHED TO OUR EAST...RESULTING IN
HIGHER THAN NORMAL RAIN CHANCES ACROSS THE LOWER DESERTS THROUGH
TUESDAY. DRIER CONDITIONS WILL RETURN BY MIDWEEK ALONG WITH ABOVE
NORMAL TEMPERATURES. WELL ABOVE NORMAL TEMPERATURES ARE POSSIBLE BY
NEXT WEEKEND.
&&
.DISCUSSION...
LATEST RAP STREAMLINE ANALYSIS SHOWS THE SUBTROPICAL RIDGE WEAKENING
ACROSS THE BAJA PENINSULA AND MIGRATING EASTWARD...RESULTING IN A
CESSATION OF THE PERSISTENT WESTERLY FLOW. A VERY WEAK STEERING FLOW
WILL DEVELOP TODAY FALLOWED BY A REVERSAL IN THE WINDS TO LIGHT
EASTERLY BY TONIGHT. MEANWHILE...A VORT MAX ASSOCIATED WITH AN
INVERTED TROUGH IS EVIDENT NEAR THE BOOTHEEL OF NM. THIS SETUP IS
FAVORABLE FOR THUNDERSTORM ACTIVITY ACROSS EASTERN AND SOUTHEASTERN
AZ TODAY WITH PROPAGATION TO THE WEST INTO SOUTH-CENTRAL AZ THIS
EVENING.
CONVECTIVELY PARAMETERIZED MODELS SUCH AS THE GFS...ECMWF AND NMM-B
SUGGEST SOME POTENTIAL FOR THUNDERSTORMS ACROSS THE LOWER DESERTS
INCLUDING THE PHOENIX AREA. HOWEVER...CONSENSUS AMONG THE CONVECTIVE
ALLOWING WRFS IS THAT CONVERGING OUTFLOW BOUNDARIES WILL PRODUCE ONLY
ISOLATED CONVECTION ACROSS THE PHOENIX AREA...BUT WITH PERHAPS HIGHER
PROBABILITIES ACROSS THE SOUTHWEST DESERTS. MOST LIKELY IMPACT
TONIGHT IS BLOWING DUST...THOUGH THE POTENTIAL CERTAINLY EXISTS FOR
THUNDERSTORMS CONTAINING STRONG WINDS AND DOWNBURSTS...PARTICULARLY
ACROSS PORTIONS OF MARICOPA AND PINAL COUNTIES. WITH THE INVERTED
TROUGH DRAPED ACROSS THE LOWER DESERTS OVERNIGHT...CONVECTION ALSO
CANNOT BE RULED OUT THROUGH MONDAY MORNING.
BEST CHANCE FOR PRECIPITATION APPEARS TO BE MONDAY AS THE MONSOON
HIGH DRIFTS TOWARDS THE FOUR CORNERS RESULTING IN A MOIST
SOUTHEASTERLY FLOW. MODELS ALSO INDICATE THAT THE 250 MB HIGH
DISPLACED TO THE SOUTH WILL PRODUCE A DIFLUENT AND DIVERGENT
PATTERN IN THE UPPER LEVELS...HELPING TO PROVIDE ASCENT WHICH MAY
OFFSET ANY LACK OF INSTABILITY DUE TO THE WIDESPREAD CLOUDINESS.
THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL PERSIST TUESDAY BUT
WILL SHIFT SOMEWHAT TO THE WEST. LATEST MODELS SUGGEST THAT SEVERAL
TRAILING VORT MAXES AND MCVS WILL PROVIDE ASCENT IN A RELATIVELY
STRONG AND MOIST SOUTHERLY FLOW. THE FOCUS FOR PRECIPITATION WILL
SHIFT NORTHWARD WEDNESDAY AS THE AFOREMENTIONED TROUGH ACCELERATES
NORTHEASTWARD AROUND THE ANTICYCLONE IN NM.
GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE RIDGE WILL AGAIN MIGRATE TO
OUR SOUTH LATE IN THE WEEK...RESULTING IN A SOUTHWESTERLY FLOW AND A
RETURN TO WARMER AND DRIER CONDITIONS. ABOVE NORMAL TEMPERATURES ARE
LIKELY BEGINNING THURSDAY WITH HIGHS IN THE PHOENIX AREA POTENTIALLY
REACHING 110 DEGREES AGAIN BY NEXT SATURDAY...AND EVEN WARMER ACROSS
SOUTHEASTERN CA. THIS COULD BE THE WARMEST AUGUST ON RECORD FOR BOTH
PHOENIX AND YUMA AND THE PERIOD OF ABOVE NORMAL TEMPERATURES TO END
THE MONTH MAY HELP CLINCH THE TOP SPOT FOR BOTH LOCATIONS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
ONCE AGAIN CONVECTION LOOKS TO BE FOCUSED WELL TO THE EAST/SOUTHEAST
OF THE GREATER PHOENIX AREA THIS EVENING...AS PERSISTENT WESTERLY
STEERING FLOW WILL HINDER THE PROGRESS OF ANY STORM THAT TRIES TO
DEVELOP OR MOVE WESTWARD AND THREATEN THE CENTRAL DESERTS AND THE
PHOENIX AREA. MOISTURE IS DOWN SLIGHTLY WITH SURFACE DEWPOINTS
MOSTLY IN THE 50S AND WE HAVE SEEN LESS CUMULUS IN THE AREA AS
COMPARED TO 24 HOURS AGO. NO MENTION OF THUNDER WILL BE IN THE AREA
TAFS TONIGHT...JUST FEW TO SCT HIGH BASED CU AND A BIT OF CIRRUS
DEBRIS CLOUDS LATER IN THE EVENING AND OVERNIGHT.
SOME HI-RES MODEL GUIDANCE SUGGESTED OUTFLOW WINDS MAY MOVE INTO THE
PHOENIX AREA AFTER 7 PM...BUT GIVEN HOW FAR AWAY FROM PHOENIX THE
STORMS CURRENTLY ARE...CONFIDENCE IN THIS IS LOW. HAVE REMOVED THE
TEMPO GROUP FOR A SOUTHEAST WIND SHIFT THIS EVENING AT KPHX BUT LEFT
IT IN FOR KIWA. CANNOT RULE OUT A WIND SHIFT TO THE SOUTHEAST LATER
THIS EVENING BUT ODDS ARE SOMEWHAT LOW THAT IT WILL OCCUR. OTHERWISE
WINDS SHOULD STAY GENERALLY WEST TIL LATE IN THE EVENING ESPECIALLY
AT KPHX.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
PERSISTENCE WIND AND CIG FORECAST FOR THE WESTERN TERMINALS WITH
BREEZY SOUTHERLY WINDS FOR KBLH...SOUTHEASTERLY WINDS FOR KIPL AND
SKC FOR THE 00Z TAF PERIOD.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
MONSOON MOISTURE LEVELS AND HUMIDITIES WILL PERSIST THROUGH MIDWEEK.
STORM CHANCES WILL CONTINUE FOR THE HIGHER TERRAIN LOCALES FOR
SUNDAY BEFORE EXPANDING INTO THE LOWER DESERT ELEVATIONS BY THE
EARLY WORK WEEK AS SOME UPPER LEVEL DISTURBANCES PASS THROUGH THE
AREA AND SUPPORT THE POTENTIAL FOR MORE WIDESPREAD STORM
DEVELOPMENT. DAYTIME HUMIDITIES WILL RANGE FROM THE 20 TO 30 PERCENT
RANGE WHILE MAKING GOOD OVERNIGHT RECOVERIES. OUTSIDE OF
THUNDERSTORM OUTFLOW AND VICINITY WINDS...SFC WINDS TO MAINTAIN
DAYTIME HEADINGS 10 TO 20 MPH WHILE BECOMING DOWN DRAINAGE/DOWN
VALLEY IN THE OVERNIGHTS. A DRAW DOWN OF MONSOON MOISTURE AND
INTRUSION OF WESTERLY FLOW ALOFT WILL RELEGATE STORM CHANCES BACK
ACROSS EASTERN AZ FOR THE LATTER PART OF THE WEEK...WHILE
TEMPERATURES ALSO BEGIN TO WARM TO ABOVE NORMAL VALUES.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...CB
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
945 AM MDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 945 AM MDT SUN AUG 23 2015
UPDATED TO ADD AREAS OF SMOKE AND HAZE FOR TODAY TO AREAS ALONG
THE LOWER EASTERN SLOPES...WEST OF THE I-25 CORRIDOR...WITH LOW
LEVEL UPSLOPE FLOW AND MID LEVEL INVERSIONS LIKELY KEEPING PAC
NORTHWEST SMOKE...BROUGHT IN BY LAST NIGHTS COLD FRONT...IN PLACE.
UPDATE ISSUED AT 743 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER AND POPS TO REFLECT CURRENT
SATELLITE AND RADAR. LOADED LATEST OBSERVATIONS INTO FRONT END OF
FORECAST GRIDS.
UPDATE ISSUED AT 647 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER PER SATELLITE AND LOADED LATEST
OBSERVATIONS INTO FRONT END OF FORECAST GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM MDT SUN AUG 23 2015
...THUNDERSTORMS MAINLY MOUNTAINS TODAY...
COLD FRONT HAS PUSHED A MASS OF RELATIVELY COOL STABLE AIR SOUTH
ACROSS THE PLAINS...WITH WIDESPREAD MID LEVEL CLOUDS ACROSS THE
EASTERN MOUNTAINS AND PLAINS BUT NO PRECIPITATION. THE MOUNTAINS
AND HIGH VALLEYS TO THE WEST REMAIN CLEAR TO PARTLY CLOUDY...WITH
SOME MOSTLY CLOUDY SKIES OVER THE EASTERN SAN JUANS.
FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW THE ONLY REAL PROSPECTS
FOR THUNDERSTORMS TO BE OVER THE MOUNTAINS AND HIGH VALLEYS. THE
PLAINS SOUNDINGS SHOW A STRONG CAP. OF NOTE...HOWEVER...ARE RUNS OF
THE EXPERIMENTAL HRRR AND...TO A LESSER EXTENT...THE 4KM NSSL
WRF...THAT SHOW SOME CONVECTION MOVING OFF THE MOUNTAINS AND ACROSS
THE I-25 CORRIDOR...MAINLY BETWEEN 4 PM AND 8 PM. NOT SURE IF THIS
WILL HAPPEN GIVEN THE STRONG CAP INDICATED IN THE FORECAST SOUNDINGS
BUT SOMETHING TO KEEP AN EYE ON. PROBABLY WHAT THESE MODELS ARE
DOING IS DEVELOPING ELEVATED CONVECTION...AND TRACKING IT SOUTHEAST
ACROSS THE PLAINS...ABOVE THE STABLE AIR. USUALLY WHEN THIS
HAPPENS...HOWEVER...ANY ELEVATED CONVECTION DIES OUT ONCE IT MOVES
OVER THE STABLE AIR. SO...SUSPECT THIS IS WHAT WILL HAPPEN.
PRIMARY THREATS FROM STORMS OVER THE MOUNTAINS AND HIGH VALLEYS
TODAY WILL BE LIGHTNING AND WIND GUSTS TO AROUND 40 MPH. THERE
COULD ALSO BE SOME SPOTTY HEAVY RAIN OUT THERE.
TEMPERATURES BEHIND THE COLD FRONT WILL BE ABOUT 15-20 DEGREES
COOLER OVER THE EAST TODAY WITH COMFORTABLE HIGHS RANGING FROM THE
MID 70S TO MID 80S. FOR THE MOUNTAINS AND HIGH VALLEYS...NOT QUITE
AS MUCH COOLING...RANGING FROM JUST A COUPLE DEGREES COOLER IN SOME
AREAS UP TO ABOUT 10 DEGREES COOLER IN OTHERS. HIGH VALLEY
TEMPERATURES SHOULD RANGE FORM THE 70S TO LOWER 80S WITH MOUNTAIN
READINGS MOSTLY IN THE 60S AND 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 534 AM MDT SUN AUG 23 2015
.MONDAY AND TUESDAY...UPPER RIDGE REMAINS OVERHEAD WITH A MODEST
AMOUNT OF MID LEVEL MOISTURE OVER THE REGION. BEST CHANCES FOR
DIURNAL CONVECTION WILL BE OVER AND NEAR THE MOUNTAINS. WITH WEAK
WINDS ALOFT...ANTICIPATE CONVECTION WILL HAVE DIFFICULTY MOVING
OFF OF THE HIGHER TERRAIN. NAM CONTINUES TO SHOW SOME INCREASED
CAPE NEAR THE KANSAS BORDER DURING THE AFTERNOON AND EVENING.
GIVEN THE LACK OF A SHORTWAVE...MAINTAINED SILENT POPS OVER THE
PLAINS. WARM WEATHER CONTINUES WITH HIGHS ABOVE AVERAGE ON BOTH
DAYS.
.WEDNESDAY AND THURSDAY...AN UPPER TROUGH WILL APPROACH THE WEST
COAST INCREASING THE INFLUX OF MONSOON MOISTURE INTO THE REGION.
LATEST SIMULATIONS HAVE WEDNESDAY BEING THE WETTEST DAY OVER AND
NEAR THE MOUNTAINS WITH GREATEST AMOUNT OF MOISTURE. GFS AND EC
DEVELOP A TROUGH OVER THE REGION WHICH SLOWLY MOVES EAST ON
THURSDAY. WITH THE TROUGH NEAR THE KANSAS BORDER BY THURSDAY
AFTERNOON...CHANCES FOR CONVECTION WILL INCREASE NEAR THE KANSAS
BORDER. HAVE CONCERNS THAT THE CONVECTIVE PARAMETERIZATION COULD
BE INFLUENCING THE DEVELOPMENT OF THIS TROUGH...WHICH COULD AFFECT
THE LOCATION...TIMING AND STRENGTH OF CONVECTION.
.FRIDAY AND SATURDAY...MODELS HAVE DIFFERENCES IN THE SPEED OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. GENERAL TREND
WILL BE TO TURN FLOW ALOFT MORE SOUTHWESTERLY BRINGING DRIER AIR
ALOFT INTO THE REGION. GRIDS GENERALLY HAVE ISOLATED TO SCATTERED
CONVECTION MOSTLY CONFINED TO THE MOUNTAINS WITH TEMPERATURE NEAR
OR ABOVE NORMAL. --PGW--
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 534 AM MDT SUN AUG 23 2015
COLD FRONT HAS BROUGHT WIDESPREAD MID LEVEL CLOUDS TO THE EASTERN
MOUNTAINS AND PLAINS THIS MORNING. THE FRONT HAS EVEN PUSHED LOW
CLOUDS UP INTO PARTS OF THE UPPER ARKANSAS RIVER VALLEY. SKIES OVER
THE SAN LUIS VALLEY AND SOUTHWEST MOUNTAINS ARE GENERALLY CLEAR OR
PARTLY CLOUDY...ALTHOUGH SKIES OVER THE SAN JUANS ARE MOSTLY CLOUDY.
LITTLE OR NO PRECIPITATION ACROSS THE FLIGHT AREA AT THIS TIME BUT
THERE ARE SOME POCKETS OF MVFR/IFR/LIFR CLOUDS OVER THE CENTRAL AND
EASTERN MOUNTAINS...AND THE UPPER ARKANSAS RIVER VALLEY. OUTSIDE
OF THE LOW CLOUDS...CONDITIONS ARE VFR THIS MORNING.
MUCH OF THE CLOUDINESS SHOULD DISSIPATE WITHIN A FEW HOURS OF
SUNRISE THIS MORNING. THEN...AFTER ABOUT 17Z...ISOLATED
THUNDERSTORMS WILL START TO DEVELOP OVER THE MOUNTAINS AND HIGH
VALLEYS...INCREASING IN COVERAGE THROUGH THE AFTERNOON...ESPECIALLY
OVER THE SOUTHERN PORTIONS OF THE MOUNTAINS AND SAN LUIS VALLEY.
A FEW STORMS COULD DRIFT OVER THE I-25 CORRIDOR BETWEEN ROUGHLY
22Z AND 02Z...BUT THESE ARE EXPECTED TO BE ISOLATED AND WEAK
DUE TO A RELATIVELY COOL...STABLE AIRMASS SITUATED OVER THE PLAINS.
GENERALLY VFR ACROSS THE FLIGHT AREA TODAY AND TONIGHT...ALTHOUGH
LOCAL MVFR/IFR/LIFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWER OR
THUNDERSTORM ACTIVITY.
FOR KCOS AND KPUB...STRATUS CLOUD BASES THIS MORNING EXPECTED TO
REMAIN HIGH ENOUGH FOR VFR. NO THUNDERSTORMS IN FORECAST FOR THESE
2 SITES IN THE AFTERNOON AS THE AIRMASS SHOULD BE TOO STABLE. FOR
KALS...NO STRATUS DECK THIS MORNING...BUT COULD BE SOME
THUNDERSTORMS IN THE AFTERNOON. THUS...12Z ISSUANCE OF TAFS WILL
INCLUDE MENTION OF VCTS AFTER 21Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...LW
LONG TERM...PGW
AVIATION...LW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
745 AM MDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 743 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER AND POPS TO REFLECT CURRENT
SATELLITE AND RADAR. LOADED LATEST OBSERVATIONS INTO FRONT END OF
FORECAST GRIDS.
UPDATE ISSUED AT 647 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER PER SATELLITE AND LOADED LATEST
OBSERVATIONS INTO FRONT END OF FORECAST GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM MDT SUN AUG 23 2015
...THUNDERSTORMS MAINLY MOUNTAINS TODAY...
COLD FRONT HAS PUSHED A MASS OF RELATIVELY COOL STABLE AIR SOUTH
ACROSS THE PLAINS...WITH WIDESPREAD MID LEVEL CLOUDS ACROSS THE
EASTERN MOUNTAINS AND PLAINS BUT NO PRECIPITATION. THE MOUNTAINS
AND HIGH VALLEYS TO THE WEST REMAIN CLEAR TO PARTLY CLOUDY...WITH
SOME MOSTLY CLOUDY SKIES OVER THE EASTERN SAN JUANS.
FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW THE ONLY REAL PROSPECTS
FOR THUNDERSTORMS TO BE OVER THE MOUNTAINS AND HIGH VALLEYS. THE
PLAINS SOUNDINGS SHOW A STRONG CAP. OF NOTE...HOWEVER...ARE RUNS OF
THE EXPERIMENTAL HRRR AND...TO A LESSER EXTENT...THE 4KM NSSL
WRF...THAT SHOW SOME CONVECTION MOVING OFF THE MOUNTAINS AND ACROSS
THE I-25 CORRIDOR...MAINLY BETWEEN 4 PM AND 8 PM. NOT SURE IF THIS
WILL HAPPEN GIVEN THE STRONG CAP INDICATED IN THE FORECAST SOUNDINGS
BUT SOMETHING TO KEEP AN EYE ON. PROBABLY WHAT THESE MODELS ARE
DOING IS DEVELOPING ELEVATED CONVECTION...AND TRACKING IT SOUTHEAST
ACROSS THE PLAINS...ABOVE THE STABLE AIR. USUALLY WHEN THIS
HAPPENS...HOWEVER...ANY ELEVATED CONVECTION DIES OUT ONCE IT MOVES
OVER THE STABLE AIR. SO...SUSPECT THIS IS WHAT WILL HAPPEN.
PRIMARY THREATS FROM STORMS OVER THE MOUNTAINS AND HIGH VALLEYS
TODAY WILL BE LIGHTNING AND WIND GUSTS TO AROUND 40 MPH. THERE
COULD ALSO BE SOME SPOTTY HEAVY RAIN OUT THERE.
TEMPERATURES BEHIND THE COLD FRONT WILL BE ABOUT 15-20 DEGREES
COOLER OVER THE EAST TODAY WITH COMFORTABLE HIGHS RANGING FROM THE
MID 70S TO MID 80S. FOR THE MOUNTAINS AND HIGH VALLEYS...NOT QUITE
AS MUCH COOLING...RANGING FROM JUST A COUPLE DEGREES COOLER IN SOME
AREAS UP TO ABOUT 10 DEGREES COOLER IN OTHERS. HIGH VALLEY
TEMPERATURES SHOULD RANGE FORM THE 70S TO LOWER 80S WITH MOUNTAIN
READINGS MOSTLY IN THE 60S AND 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 534 AM MDT SUN AUG 23 2015
.MONDAY AND TUESDAY...UPPER RIDGE REMAINS OVERHEAD WITH A MODEST
AMOUNT OF MID LEVEL MOISTURE OVER THE REGION. BEST CHANCES FOR
DIURNAL CONVECTION WILL BE OVER AND NEAR THE MOUNTAINS. WITH WEAK
WINDS ALOFT...ANTICIPATE CONVECTION WILL HAVE DIFFICULTY MOVING
OFF OF THE HIGHER TERRAIN. NAM CONTINUES TO SHOW SOME INCREASED
CAPE NEAR THE KANSAS BORDER DURING THE AFTERNOON AND EVENING.
GIVEN THE LACK OF A SHORTWAVE...MAINTAINED SILENT POPS OVER THE
PLAINS. WARM WEATHER CONTINUES WITH HIGHS ABOVE AVERAGE ON BOTH
DAYS.
.WEDNESDAY AND THURSDAY...AN UPPER TROUGH WILL APPROACH THE WEST
COAST INCREASING THE INFLUX OF MONSOON MOISTURE INTO THE REGION.
LATEST SIMULATIONS HAVE WEDNESDAY BEING THE WETTEST DAY OVER AND
NEAR THE MOUNTAINS WITH GREATEST AMOUNT OF MOISTURE. GFS AND EC
DEVELOP A TROUGH OVER THE REGION WHICH SLOWLY MOVES EAST ON
THURSDAY. WITH THE TROUGH NEAR THE KANSAS BORDER BY THURSDAY
AFTERNOON...CHANCES FOR CONVECTION WILL INCREASE NEAR THE KANSAS
BORDER. HAVE CONCERNS THAT THE CONVECTIVE PARAMETERIZATION COULD
BE INFLUENCING THE DEVELOPMENT OF THIS TROUGH...WHICH COULD AFFECT
THE LOCATION...TIMING AND STRENGTH OF CONVECTION.
.FRIDAY AND SATURDAY...MODELS HAVE DIFFERENCES IN THE SPEED OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. GENERAL TREND
WILL BE TO TURN FLOW ALOFT MORE SOUTHWESTERLY BRINGING DRIER AIR
ALOFT INTO THE REGION. GRIDS GENERALLY HAVE ISOLATED TO SCATTERED
CONVECTION MOSTLY CONFINED TO THE MOUNTAINS WITH TEMPERATURE NEAR
OR ABOVE NORMAL. --PGW--
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 534 AM MDT SUN AUG 23 2015
COLD FRONT HAS BROUGHT WIDESPREAD MID LEVEL CLOUDS TO THE EASTERN
MOUNTAINS AND PLAINS THIS MORNING. THE FRONT HAS EVEN PUSHED LOW
CLOUDS UP INTO PARTS OF THE UPPER ARKANSAS RIVER VALLEY. SKIES OVER
THE SAN LUIS VALLEY AND SOUTHWEST MOUNTAINS ARE GENERALLY CLEAR OR
PARTLY CLOUDY...ALTHOUGH SKIES OVER THE SAN JUANS ARE MOSTLY CLOUDY.
LITTLE OR NO PRECIPITATION ACROSS THE FLIGHT AREA AT THIS TIME BUT
THERE ARE SOME POCKETS OF MVFR/IFR/LIFR CLOUDS OVER THE CENTRAL AND
EASTERN MOUNTAINS...AND THE UPPER ARKANSAS RIVER VALLEY. OUTSIDE
OF THE LOW CLOUDS...CONDITIONS ARE VFR THIS MORNING.
MUCH OF THE CLOUDINESS SHOULD DISSIPATE WITHIN A FEW HOURS OF
SUNRISE THIS MORNING. THEN...AFTER ABOUT 17Z...ISOLATED
THUNDERSTORMS WILL START TO DEVELOP OVER THE MOUNTAINS AND HIGH
VALLEYS...INCREASING IN COVERAGE THROUGH THE AFTERNOON...ESPECIALLY
OVER THE SOUTHERN PORTIONS OF THE MOUNTAINS AND SAN LUIS VALLEY.
A FEW STORMS COULD DRIFT OVER THE I-25 CORRIDOR BETWEEN ROUGHLY
22Z AND 02Z...BUT THESE ARE EXPECTED TO BE ISOLATED AND WEAK
DUE TO A RELATIVELY COOL...STABLE AIRMASS SITUATED OVER THE PLAINS.
GENERALLY VFR ACROSS THE FLIGHT AREA TODAY AND TONIGHT...ALTHOUGH
LOCAL MVFR/IFR/LIFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWER OR
THUNDERSTORM ACTIVITY.
FOR KCOS AND KPUB...STRATUS CLOUD BASES THIS MORNING EXPECTED TO
REMAIN HIGH ENOUGH FOR VFR. NO THUNDERSTORMS IN FORECAST FOR THESE
2 SITES IN THE AFTERNOON AS THE AIRMASS SHOULD BE TOO STABLE. FOR
KALS...NO STRATUS DECK THIS MORNING...BUT COULD BE SOME
THUNDERSTORMS IN THE AFTERNOON. THUS...12Z ISSUANCE OF TAFS WILL
INCLUDE MENTION OF VCTS AFTER 21Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LW
SHORT TERM...LW
LONG TERM...PGW
AVIATION...LW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
650 AM MDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 647 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER PER SATELLITE AND LOADED LATEST
OBSERVATIONS INTO FRONT END OF FORECAST GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM MDT SUN AUG 23 2015
...THUNDERSTORMS MAINLY MOUNTAINS TODAY...
COLD FRONT HAS PUSHED A MASS OF RELATIVELY COOL STABLE AIR SOUTH
ACROSS THE PLAINS...WITH WIDESPREAD MID LEVEL CLOUDS ACROSS THE
EASTERN MOUNTAINS AND PLAINS BUT NO PRECIPITATION. THE MOUNTAINS
AND HIGH VALLEYS TO THE WEST REMAIN CLEAR TO PARTLY CLOUDY...WITH
SOME MOSTLY CLOUDY SKIES OVER THE EASTERN SAN JUANS.
FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW THE ONLY REAL PROSPECTS
FOR THUNDERSTORMS TO BE OVER THE MOUNTAINS AND HIGH VALLEYS. THE
PLAINS SOUNDINGS SHOW A STRONG CAP. OF NOTE...HOWEVER...ARE RUNS OF
THE EXPERIMENTAL HRRR AND...TO A LESSER EXTENT...THE 4KM NSSL
WRF...THAT SHOW SOME CONVECTION MOVING OFF THE MOUNTAINS AND ACROSS
THE I-25 CORRIDOR...MAINLY BETWEEN 4 PM AND 8 PM. NOT SURE IF THIS
WILL HAPPEN GIVEN THE STRONG CAP INDICATED IN THE FORECAST SOUNDINGS
BUT SOMETHING TO KEEP AN EYE ON. PROBABLY WHAT THESE MODELS ARE
DOING IS DEVELOPING ELEVATED CONVECTION...AND TRACKING IT SOUTHEAST
ACROSS THE PLAINS...ABOVE THE STABLE AIR. USUALLY WHEN THIS
HAPPENS...HOWEVER...ANY ELEVATED CONVECTION DIES OUT ONCE IT MOVES
OVER THE STABLE AIR. SO...SUSPECT THIS IS WHAT WILL HAPPEN.
PRIMARY THREATS FROM STORMS OVER THE MOUNTAINS AND HIGH VALLEYS
TODAY WILL BE LIGHTNING AND WIND GUSTS TO AROUND 40 MPH. THERE
COULD ALSO BE SOME SPOTTY HEAVY RAIN OUT THERE.
TEMPERATURES BEHIND THE COLD FRONT WILL BE ABOUT 15-20 DEGREES
COOLER OVER THE EAST TODAY WITH COMFORTABLE HIGHS RANGING FROM THE
MID 70S TO MID 80S. FOR THE MOUNTAINS AND HIGH VALLEYS...NOT QUITE
AS MUCH COOLING...RANGING FROM JUST A COUPLE DEGREES COOLER IN SOME
AREAS UP TO ABOUT 10 DEGREES COOLER IN OTHERS. HIGH VALLEY
TEMPERATURES SHOULD RANGE FORM THE 70S TO LOWER 80S WITH MOUNTAIN
READINGS MOSTLY IN THE 60S AND 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 534 AM MDT SUN AUG 23 2015
.MONDAY AND TUESDAY...UPPER RIDGE REMAINS OVERHEAD WITH A MODEST
AMOUNT OF MID LEVEL MOISTURE OVER THE REGION. BEST CHANCES FOR
DIURNAL CONVECTION WILL BE OVER AND NEAR THE MOUNTAINS. WITH WEAK
WINDS ALOFT...ANTICIPATE CONVECTION WILL HAVE DIFFICULTY MOVING
OFF OF THE HIGHER TERRAIN. NAM CONTINUES TO SHOW SOME INCREASED
CAPE NEAR THE KANSAS BORDER DURING THE AFTERNOON AND EVENING.
GIVEN THE LACK OF A SHORTWAVE...MAINTAINED SILENT POPS OVER THE
PLAINS. WARM WEATHER CONTINUES WITH HIGHS ABOVE AVERAGE ON BOTH
DAYS.
.WEDNESDAY AND THURSDAY...AN UPPER TROUGH WILL APPROACH THE WEST
COAST INCREASING THE INFLUX OF MONSOON MOISTURE INTO THE REGION.
LATEST SIMULATIONS HAVE WEDNESDAY BEING THE WETTEST DAY OVER AND
NEAR THE MOUNTAINS WITH GREATEST AMOUNT OF MOISTURE. GFS AND EC
DEVELOP A TROUGH OVER THE REGION WHICH SLOWLY MOVES EAST ON
THURSDAY. WITH THE TROUGH NEAR THE KANSAS BORDER BY THURSDAY
AFTERNOON...CHANCES FOR CONVECTION WILL INCREASE NEAR THE KANSAS
BORDER. HAVE CONCERNS THAT THE CONVECTIVE PARAMETERIZATION COULD
BE INFLUENCING THE DEVELOPMENT OF THIS TROUGH...WHICH COULD AFFECT
THE LOCATION...TIMING AND STRENGTH OF CONVECTION.
.FRIDAY AND SATURDAY...MODELS HAVE DIFFERENCES IN THE SPEED OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. GENERAL TREND
WILL BE TO TURN FLOW ALOFT MORE SOUTHWESTERLY BRINGING DRIER AIR
ALOFT INTO THE REGION. GRIDS GENERALLY HAVE ISOLATED TO SCATTERED
CONVECTION MOSTLY CONFINED TO THE MOUNTAINS WITH TEMPERATURE NEAR
OR ABOVE NORMAL. --PGW--
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 534 AM MDT SUN AUG 23 2015
COLD FRONT HAS BROUGHT WIDESPREAD MID LEVEL CLOUDS TO THE EASTERN
MOUNTAINS AND PLAINS THIS MORNING. THE FRONT HAS EVEN PUSHED LOW
CLOUDS UP INTO PARTS OF THE UPPER ARKANSAS RIVER VALLEY. SKIES OVER
THE SAN LUIS VALLEY AND SOUTHWEST MOUNTAINS ARE GENERALLY CLEAR OR
PARTLY CLOUDY...ALTHOUGH SKIES OVER THE SAN JUANS ARE MOSTLY CLOUDY.
LITTLE OR NO PRECIPITATION ACROSS THE FLIGHT AREA AT THIS TIME BUT
THERE ARE SOME POCKETS OF MVFR/IFR/LIFR CLOUDS OVER THE CENTRAL AND
EASTERN MOUNTAINS...AND THE UPPER ARKANSAS RIVER VALLEY. OUTSIDE
OF THE LOW CLOUDS...CONDITIONS ARE VFR THIS MORNING.
MUCH OF THE CLOUDINESS SHOULD DISSIPATE WITHIN A FEW HOURS OF
SUNRISE THIS MORNING. THEN...AFTER ABOUT 17Z...ISOLATED
THUNDERSTORMS WILL START TO DEVELOP OVER THE MOUNTAINS AND HIGH
VALLEYS...INCREASING IN COVERAGE THROUGH THE AFTERNOON...ESPECIALLY
OVER THE SOUTHERN PORTIONS OF THE MOUNTAINS AND SAN LUIS VALLEY.
A FEW STORMS COULD DRIFT OVER THE I-25 CORRIDOR BETWEEN ROUGHLY
22Z AND 02Z...BUT THESE ARE EXPECTED TO BE ISOLATED AND WEAK
DUE TO A RELATIVELY COOL...STABLE AIRMASS SITUATED OVER THE PLAINS.
GENERALLY VFR ACROSS THE FLIGHT AREA TODAY AND TONIGHT...ALTHOUGH
LOCAL MVFR/IFR/LIFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWER OR
THUNDERSTORM ACTIVITY.
FOR KCOS AND KPUB...STRATUS CLOUD BASES THIS MORNING EXPECTED TO
REMAIN HIGH ENOUGH FOR VFR. NO THUNDERSTORMS IN FORECAST FOR THESE
2 SITES IN THE AFTERNOON AS THE AIRMASS SHOULD BE TOO STABLE. FOR
KALS...NO STRATUS DECK THIS MORNING...BUT COULD BE SOME
THUNDERSTORMS IN THE AFTERNOON. THUS...12Z ISSUANCE OF TAFS WILL
INCLUDE MENTION OF VCTS AFTER 21Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LW
SHORT TERM...LW
LONG TERM...PGW
AVIATION...LW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
535 AM MDT SUN AUG 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM MDT SUN AUG 23 2015
...THUNDERSTORMS MAINLY MOUNTAINS TODAY...
COLD FRONT HAS PUSHED A MASS OF RELATIVELY COOL STABLE AIR SOUTH
ACROSS THE PLAINS...WITH WIDESPREAD MID LEVEL CLOUDS ACROSS THE
EASTERN MOUNTAINS AND PLAINS BUT NO PRECIPITATION. THE MOUNTAINS
AND HIGH VALLEYS TO THE WEST REMAIN CLEAR TO PARTLY CLOUDY...WITH
SOME MOSTLY CLOUDY SKIES OVER THE EASTERN SAN JUANS.
FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW THE ONLY REAL PROSPECTS
FOR THUNDERSTORMS TO BE OVER THE MOUNTAINS AND HIGH VALLEYS. THE
PLAINS SOUNDINGS SHOW A STRONG CAP. OF NOTE...HOWEVER...ARE RUNS OF
THE EXPERIMENTAL HRRR AND...TO A LESSER EXTENT...THE 4KM NSSL
WRF...THAT SHOW SOME CONVECTION MOVING OFF THE MOUNTAINS AND ACROSS
THE I-25 CORRIDOR...MAINLY BETWEEN 4 PM AND 8 PM. NOT SURE IF THIS
WILL HAPPEN GIVEN THE STRONG CAP INDICATED IN THE FORECAST SOUNDINGS
BUT SOMETHING TO KEEP AN EYE ON. PROBABLY WHAT THESE MODELS ARE
DOING IS DEVELOPING ELEVATED CONVECTION...AND TRACKING IT SOUTHEAST
ACROSS THE PLAINS...ABOVE THE STABLE AIR. USUALLY WHEN THIS
HAPPENS...HOWEVER...ANY ELEVATED CONVECTION DIES OUT ONCE IT MOVES
OVER THE STABLE AIR. SO...SUSPECT THIS IS WHAT WILL HAPPEN.
PRIMARY THREATS FROM STORMS OVER THE MOUNTAINS AND HIGH VALLEYS
TODAY WILL BE LIGHTNING AND WIND GUSTS TO AROUND 40 MPH. THERE
COULD ALSO BE SOME SPOTTY HEAVY RAIN OUT THERE.
TEMPERATURES BEHIND THE COLD FRONT WILL BE ABOUT 15-20 DEGREES
COOLER OVER THE EAST TODAY WITH COMFORTABLE HIGHS RANGING FROM THE
MID 70S TO MID 80S. FOR THE MOUNTAINS AND HIGH VALLEYS...NOT QUITE
AS MUCH COOLING...RANGING FROM JUST A COUPLE DEGREES COOLER IN SOME
AREAS UP TO ABOUT 10 DEGREES COOLER IN OTHERS. HIGH VALLEY
TEMPERATURES SHOULD RANGE FORM THE 70S TO LOWER 80S WITH MOUNTAIN
READINGS MOSTLY IN THE 60S AND 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 534 AM MDT SUN AUG 23 2015
.MONDAY AND TUESDAY...UPPER RIDGE REMAINS OVERHEAD WITH A MODEST
AMOUNT OF MID LEVEL MOISTURE OVER THE REGION. BEST CHANCES FOR
DIURNAL CONVECTION WILL BE OVER AND NEAR THE MOUNTAINS. WITH WEAK
WINDS ALOFT...ANTICIPATE CONVECTION WILL HAVE DIFFICULTY MOVING
OFF OF THE HIGHER TERRAIN. NAM CONTINUES TO SHOW SOME INCREASED
CAPE NEAR THE KANSAS BORDER DURING THE AFTERNOON AND EVENING.
GIVEN THE LACK OF A SHORTWAVE...MAINTAINED SILENT POPS OVER THE
PLAINS. WARM WEATHER CONTINUES WITH HIGHS ABOVE AVERAGE ON BOTH
DAYS.
.WEDNESDAY AND THURSDAY...AN UPPER TROUGH WILL APPROACH THE WEST
COAST INCREASING THE INFLUX OF MONSOON MOISTURE INTO THE REGION.
LATEST SIMULATIONS HAVE WEDNESDAY BEING THE WETTEST DAY OVER AND
NEAR THE MOUNTAINS WITH GREATEST AMOUNT OF MOISTURE. GFS AND EC
DEVELOP A TROUGH OVER THE REGION WHICH SLOWLY MOVES EAST ON
THURSDAY. WITH THE TROUGH NEAR THE KANSAS BORDER BY THURSDAY
AFTERNOON...CHANCES FOR CONVECTION WILL INCREASE NEAR THE KANSAS
BORDER. HAVE CONCERNS THAT THE CONVECTIVE PARAMETERIZATION COULD
BE INFLUENCING THE DEVELOPMENT OF THIS TROUGH...WHICH COULD AFFECT
THE LOCATION...TIMING AND STRENGTH OF CONVECTION.
.FRIDAY AND SATURDAY...MODELS HAVE DIFFERENCES IN THE SPEED OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. GENERAL TREND
WILL BE TO TURN FLOW ALOFT MORE SOUTHWESTERLY BRINGING DRIER AIR
ALOFT INTO THE REGION. GRIDS GENERALLY HAVE ISOLATED TO SCATTERED
CONVECTION MOSTLY CONFINED TO THE MOUNTAINS WITH TEMPERATURE NEAR
OR ABOVE NORMAL. --PGW--
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 534 AM MDT SUN AUG 23 2015
COLD FRONT HAS BROUGHT WIDESPREAD MID LEVEL CLOUDS TO THE EASTERN
MOUNTAINS AND PLAINS THIS MORNING. THE FRONT HAS EVEN PUSHED LOW
CLOUDS UP INTO PARTS OF THE UPPER ARKANSAS RIVER VALLEY. SKIES OVER
THE SAN LUIS VALLEY AND SOUTHWEST MOUNTAINS ARE GENERALLY CLEAR OR
PARTLY CLOUDY...ALTHOUGH SKIES OVER THE SAN JUANS ARE MOSTLY CLOUDY.
LITTLE OR NO PRECIPITATION ACROSS THE FLIGHT AREA AT THIS TIME BUT
THERE ARE SOME POCKETS OF MVFR/IFR/LIFR CLOUDS OVER THE CENTRAL AND
EASTERN MOUNTAINS...AND THE UPPER ARKANSAS RIVER VALLEY. OUTSIDE
OF THE LOW CLOUDS...CONDITIONS ARE VFR THIS MORNING.
MUCH OF THE CLOUDINESS SHOULD DISSIPATE WITHIN A FEW HOURS OF
SUNRISE THIS MORNING. THEN...AFTER ABOUT 17Z...ISOLATED
THUNDERSTORMS WILL START TO DEVELOP OVER THE MOUNTAINS AND HIGH
VALLEYS...INCREASING IN COVERAGE THROUGH THE AFTERNOON...ESPECIALLY
OVER THE SOUTHERN PORTIONS OF THE MOUNTAINS AND SAN LUIS VALLEY.
A FEW STORMS COULD DRIFT OVER THE I-25 CORRIDOR BETWEEN ROUGHLY
22Z AND 02Z...BUT THESE ARE EXPECTED TO BE ISOLATED AND WEAK
DUE TO A RELATIVELY COOL...STABLE AIRMASS SITUATED OVER THE PLAINS.
GENERALLY VFR ACROSS THE FLIGHT AREA TODAY AND TONIGHT...ALTHOUGH
LOCAL MVFR/IFR/LIFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWER OR
THUNDERSTORM ACTIVITY.
FOR KCOS AND KPUB...STRATUS CLOUD BASES THIS MORNING EXPECTED TO
REMAIN HIGH ENOUGH FOR VFR. NO THUNDERSTORMS IN FORECAST FOR THESE
2 SITES IN THE AFTERNOON AS THE AIRMASS SHOULD BE TOO STABLE. FOR
KALS...NO STRATUS DECK THIS MORNING...BUT COULD BE SOME
THUNDERSTORMS IN THE AFTERNOON. THUS...12Z ISSUANCE OF TAFS WILL
INCLUDE MENTION OF VCTS AFTER 21Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LW
LONG TERM...PGW
AVIATION...LW
AREA FORECAST DISCUSSION...CORRECTED
NWS PUEBLO CO
444 AM MDT SUN AUG 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 444 AM MDT SUN AUG 23 2015
...THUNDERSTORMS MAINLY MOUNTAINS TODAY...
COLD FRONT HAS PUSHED A MASS OF RELATIVELY COOL STABLE AIR SOUTH
ACROSS THE PLAINS...WITH WIDESPREAD MID LEVEL CLOUDS ACROSS THE
EASTERN MOUNTAINS AND PLAINS BUT NO PRECIPITATION. THE MOUNTAINS
AND HIGH VALLEYS TO THE WEST REMAIN CLEAR TO PARTLY CLOUDY...WITH
SOME MOSTLY CLOUDY SKIES OVER THE EASTERN SAN JUANS.
FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW THE ONLY REAL PROSPECTS
FOR THUNDERSTORMS TO BE OVER THE MOUNTAINS AND HIGH VALLEYS. THE
PLAINS SOUNDINGS SHOW A STRONG CAP. OF NOTE...HOWEVER...ARE RUNS OF
THE EXPERIMENTAL HRRR AND...TO A LESSER EXTENT...THE 4KM NSSL
WRF...THAT SHOW SOME CONVECTION MOVING OFF THE MOUNTAINS AND ACROSS
THE I-25 CORRIDOR...MAINLY BETWEEN 4 PM AND 8 PM. NOT SURE IF THIS
WILL HAPPEN GIVEN THE STRONG CAP INDICATED IN THE FORECAST SOUNDINGS
BUT SOMETHING TO KEEP AN EYE ON. PROBABLY WHAT THESE MODELS ARE
DOING IS DEVELOPING ELEVATED CONVECTION...AND TRACKING IT SOUTHEAST
ACROSS THE PLAINS...ABOVE THE STABLE AIR. USUALLY WHEN THIS
HAPPENS...HOWEVER...ANY ELEVATED CONVECTION DIES OUT ONCE IT MOVES
OVER THE STABLE AIR. SO...SUSPECT THIS IS WHAT WILL HAPPEN.
PRIMARY THREATS FROM STORMS OVER THE MOUNTAINS AND HIGH VALLEYS
TODAY WILL BE LIGHTNING AND WIND GUSTS TO AROUND 40 MPH. THERE
COULD ALSO BE SOME SPOTTY HEAVY RAIN OUT THERE.
TEMPERATURES BEHIND THE COLD FRONT WILL BE ABOUT 15-20 DEGREES
COOLER OVER THE EAST TODAY WITH COMFORTABLE HIGHS RANGING FROM THE
MID 70S TO MID 80S. FOR THE MOUNTAINS AND HIGH VALLEYS...NOT QUITE
AS MUCH COOLING...RANGING FROM JUST A COUPLE DEGREES COOLER IN SOME
AREAS UP TO ABOUT 10 DEGREES COOLER IN OTHERS. HIGH VALLEY
TEMPERATURES SHOULD RANGE FORM THE 70S TO LOWER 80S WITH MOUNTAIN
READINGS MOSTLY IN THE 60S AND 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 444 AM MDT SUN AUG 23 2015
.MONDAY AND TUESDAY...UPPER RIDGE REMAINS OVERHEAD WITH A MODEST
AMOUNT OF MID LEVEL MOISTURE OVER THE REGION. BEST CHANCES FOR
DIURNAL CONVECTION WILL BE OVER AND NEAR THE MOUNTAINS. WITH WEAK
WINDS ALOFT...ANTICIPATE CONVECTION WILL HAVE DIFFICULTY MOVING
OFF OF THE HIGHER TERRAIN. NAM CONTINUES TO SHOW SOME INCREASED
CAPE NEAR THE KANSAS BORDER DURING THE AFTERNOON AND EVENING.
GIVEN THE LACK OF A SHORTWAVE...MAINTAINED SILENT POPS OVER THE
PLAINS. WARM WEATHER CONTINUES WITH HIGHS ABOVE AVERAGE ON BOTH
DAYS.
.WEDNESDAY AND THURSDAY...AN UPPER TROUGH WILL APPROACH THE WEST
COAST INCREASING THE INFLUX OF MONSOON MOISTURE INTO THE REGION.
LATEST SIMULATIONS HAVE WEDNESDAY BEING THE WETTEST DAY OVER AND
NEAR THE MOUNTAINS WITH GREATEST AMOUNT OF MOISTURE. GFS AND EC
DEVELOP A TROUGH OVER THE REGION WHICH SLOWLY MOVES EAST ON
THURSDAY. WITH THE TROUGH NEAR THE KANSAS BORDER BY THURSDAY
AFTERNOON...CHANCES FOR CONVECTION WILL INCREASE NEAR THE KANSAS
BORDER. HAVE CONCERNS THAT THE CONVECTIVE PARAMETERIZATION COULD
BE INFLUENCING THE DEVELOPMENT OF THIS TROUGH...WHICH COULD AFFECT
THE LOCATION...TIMING AND STRENGTH OF CONVECTION.
.FRIDAY AND SATURDAY...MODELS HAVE DIFFERENCES IN THE SPEED OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. GENERAL TREND
WILL BE TO TURN FLOW ALOFT MORE SOUTHWESTERLY BRINGING DRIER AIR
ALOFT INTO THE REGION. GRIDS GENERALLY HAVE ISOLATED TO SCATTERED
CONVECTION MOSTLY CONFINED TO THE MOUNTAINS WITH TEMPERATURE NEAR
OR ABOVE NORMAL. --PGW--
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 444 AM MDT SUN AUG 23 2015
COLD FRONT HAS BROUGHT WIDESPREAD MID LEVEL CLOUDS TO THE EASTERN
MOUNTAINS AND PLAINS THIS MORNING. THE FRONT HAS EVEN PUSHED LOW
CLOUDS UP INTO PARTS OF THE UPPER ARKANSAS RIVER VALLEY. SKIES OVER
THE SAN LUIS VALLEY AND SOUTHWEST MOUNTAINS ARE GENERALLY CLEAR OR
PARTLY CLOUDY...ALTHOUGH SKIES OVER THE SAN JUANS ARE MOSTLY CLOUDY.
LITTLE OR NO PRECIPITATION ACROSS THE FLIGHT AREA AT THIS TIME BUT
THERE ARE SOME POCKETS OF MVFR/IFR/LIFR CLOUDS OVER THE CENTRAL AND
EASTERN MOUNTAINS...AND THE UPPER ARKANSAS RIVER VALLEY. OUTSIDE
OF THE LOW CLOUDS...CONDITIONS ARE VFR THIS MORNING.
MUCH OF THE CLOUDINESS SHOULD DISSIPATE WITHIN A FEW HOURS OF
SUNRISE THIS MORNING. THEN...AFTER ABOUT 17Z...ISOLATED
THUNDERSTORMS WILL START TO DEVELOP OVER THE MOUNTAINS AND HIGH
VALLEYS...INCREASING IN COVERAGE THROUGH THE AFTERNOON...ESPECIALLY
OVER THE SOUTHERN PORTIONS OF THE MOUNTAINS AND SAN LUIS VALLEY.
A FEW STORMS COULD DRIFT OVER THE I-25 CORRIDOR BETWEEN ROUGHLY
22Z AND 02Z...BUT THESE ARE EXPECTED TO BE ISOLATED AND WEAK
DUE TO A RELATIVELY COOL...STABLE AIRMASS SITUATED OVER THE PLAINS.
GENERALLY VFR ACROSS THE FLIGHT AREA TODAY AND TONIGHT...ALTHOUGH
LOCAL MVFR/IFR/LIFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWER OR
THUNDERSTORM ACTIVITY.
FOR KCOS AND KPUB...STRATUS CLOUD BASES THIS MORNING EXPECTED TO
REMAIN HIGH ENOUGH FOR VFR. NO THUNDERSTORMS IN FORECAST FOR THESE
2 SITES IN THE AFTERNOON AS THE AIRMASS SHOULD BE TOO STABLE. FOR
KALS...NO STRATUS DECK THIS MORNING...BUT COULD BE SOME
THUNDERSTORMS IN THE AFTERNOON. THUS...12Z ISSUANCE OF TAFS WILL
INCLUDE MENTION OF VCTS AFTER 21Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LW
LONG TERM...PGW
AVIATION...LW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
935 AM EDT SUN AUG 23 2015
.UPDATE...
CURRENT-THIS AFTERNOON...HIGH PRESSURE STRETCHING FROM VIRGINIA TO
MISSISSIPPI RIDGES OVER FLORIDA. CURRENT(9AM) WEATHER ROUNDUP
INDICATING CALM TO LIGHT W THROUGH NE WINDS. WINDS BECOME NORTH TO
NORTHEAST LATE MORNING AS WINDS OFF THE SURFACE MIX DOWN. SEA
BREEZES AT THE COAST EARLY AFTERNOON PUSH INLAND THE REST OF THE
DAY. PRECIPITABLE WATER VALUES AVERAGING AROUND 2 INCHES NORTH HALF
OF FLORIDA. THE 12Z SOUNDINGS INDICATED THAT THE TEMPERATURES ALOFT
WERE STILL QUICK WARM WITH -6C AT 500MB AND 10 TO 12C AT 700MB.
THESE NUMBERS SUPPORT CHANCE/SCATTERED AFTERNOON POPS WHICH THE
CURRENT FORECAST INDICATES.
WILL UPDATE THE VARIOUS WINDS GRIDS FOR THE AFTERNOON AND BACKFILL
THE GRIDS BEFORE 12Z.
&&
.AVIATION...SYNOPTIC/MESOSCALE SETUP LOOKS SIMILAR TO SAT WITH
PERHAPS A TOUGH MORE LOW LEVEL NE FLOW BUT STEERING WINDS OUT OF THE
NORTH ONCE AGAIN. HRRR ALSO SHOWS DIURNAL CONVECTIVE EVOLUTION VERY
SIMILAR TO SATURDAY. CONSEQUENTLY...EXPECT ISOLD TS TO SET UP WEST
OF THE DAB-SUA CORRIDOR AROUND 17Z...WITH SEA BREEZE CARRYING THE
ACTIVITY WELL INLAND AFTER 19Z. POPS SUPPORT MENTION OF VCTS...16Z-
19Z FOR THE COAST...AND 18Z-23Z FOR THE INTERIOR...WITH VARIANCE IN
TIMING DEPENDING ON THE LOCATION.
&&
.MARINE... CURRENT-THIS AFTERNOON...BUOYS RECORDING NW-NNE WINDS 5
TO 10 KNOTS AND 1 TO 2 FOOT SEAS. NEARSHORE WINDS TO BECOME ONSHORE
AND PICK UP TO AROUND 10 KNOTS ONCE THE SEA BREEZES KICK IN AND PUSH
INLAND.
CURRENT MARINE FORECAST SHOWS THE TRANSITION AND SPEEDS TO BE UPDATE
ALONG WITH ZONES(ON LAND) WINDS.
&&
IMPACT WX/AVIATION...CRISTALDI
UPDATES/FORECASTS....WIMMER
&&
.PREVIOUS DISCUSSION... /ISSUED 340 AM EDT SUN AUG 23 2015/
TONIGHT...ONSHORE WINDS WILL WEAKEN TONIGHT AND BECOME LIGHT. ENOUGH
DRYING IS ANTICIPATED TO KEEP POPS OUT OF THE FORECAST.
MON-MON NIGHT...AN ELONGATED SHORTWAVE TROUGH IN THE MID-LEVELS
ACROSS THE DEEP SOUTH EARLY IN THE PERIOD WILL SLIDE DOWN INTO THE
CENTRAL FLORIDA PENINSULA DURING THE DAY AND WEAKEN. WEAK HIGH
PRESSURE WILL BE OVER ECFL AS A WEAK FRONTAL BOUNDARY SETS UP OVER
THE GULF COAST STATES AND ACROSS THE SOUTHEAST U.S. LIGHT/VARIABLE
EARLY MORNING WINDS WILL BECOME LIGHT NNE/NE THROUGH THE DAY. THE
ECSB WILL DEVELOP AND MOVE INLAND WITH ONLY A SMALL THREAT FOR A
SHOWER/STORM OVER COASTAL COUNTIES WITH POPS INCREASING TO AROUND 30
PERCENT OVER THE INTERIOR THROUGH THE AFTERNOON/EARLY EVENING. STORM
STEERING FLOW REMAINS LIGHT NORTHERLY. MID-LEVEL TEMPERATURES REMAIN
WARM (700/500MB +10C/-5C RESPECTIVELY). WINDS WILL BECOME LIGHT
AGAIN MON NIGHT. HIGHS FORECAST IN THE L90S ALONG THE COAST AND M90S
INTO THE INTERIOR. OVERNIGHT LOWS WELL INTO THE 70S STILL.
TUE-TUE NIGHT...UPPER TROUGHING DEEPENS OVER THE EASTERN CONUS AS
UPPER RIDGING AMPLIFIES OVER THE DESERT SOUTHWEST/ROCKY MOUNTAINS.
THIS WILL ALLOW FOR A MORE UNIFORM SWRLY FLOW IN THE MID/UPPER
LEVELS TO BEGIN TO DEVELOP ACROSS THE FLORIDA PENINSULA. THE WEAK
FRONTAL BOUNDARY TO THE NORTH REMAINS QUASI-STATIONARY ACROSS THE
NORTH GULF/NORTH FLORIDA. LIGHT SW/WSW FLOW WILL BE FOUND OVER ECFL
DURING THE MORNING/EARLY AFTERNOON WITH WINDS BACKING ESE/SE NEAR
THE COAST WITH SEA BREEZE DEVELOPMENT. MID-LEVEL TEMPERATURES
SLIGHTLY COOLER AT 500MB WITH STORM MOTION OUT OF THE W/NW AROUND 5
MPH. PRECIPITATION CHANCES INCREASE TO 40 PERCENT INTERIOR AND 20-30
PERCENT TOWARD THE EAST COAST.
WED-SAT...UPPER TROUGHING PERSISTS INTO THE EXTENDED BUT DOES BEGIN
TO WEAKEN LATE IN THE WEEK. THE AFOREMENTIONED WEAK SURFACE BOUNDARY
TO THE NORTH REMAINS IN PLACE WITH DEEP LAYER MOISTURE POOLING
ALONG/AHEAD OF IT. THE GFS BRINGS SOME DRIER AIR INTO THE AREA FROM
THE NORTH ON THU INTO SAT BUT THIS WILL BE DEPENDENT ON THE FRONT TO
THE NORTH EITHER MOVING FURTHER SOUTH/DISSIPATING ALTOGETHER. FOR
NOW WITH THE SWRLY STORM MOTION THROUGH THE PERIOD BELIEVE HIGH END
CHANCE TO LIKELY POPS APPROPRIATE FOR ALMOST EACH AFTERNOON/EARLY
EVENING WITH THE EASTERN PENINSULA HAVING GREATEST CHANCES THROUGH
THIS PERIOD. COOLER AIR ALOFT (500MB/-7C TO -8C) IS FORECAST. SOME
SORT OF ECSB DEVELOPMENT IS FORECAST EACH DAY BUT INLAND MOVEMENT
LIKELY SLOWED BY SWRLY FLOW OFF OF THE SURFACE. PRECIPITABLE WATER
VALUES IN UPWARDS OF 2 INCHES ALONG AND SOUTH OF THE SURFACE
BOUNDARY.
&&
.AVIATION...
LOCAL MVFR PRESENTLY ALONG THE COAST IN/NEAR SHOWERS...WILL BECOME
MORE COMMON THROUGH SUNRISE. THERE IS A SLIGHT CHANCE FOR IFR IN
SOME OF THE SHOWERS THAT MOVE ONSHORE. ONCE DAYTIME HEATING KICKS
IN BY LATE MORNING...SCATTERED SHOWERS/ISOLATED STORMS WILL FORM
JUST INLAND ALONG THE SEA BREEZE BOUNDARY. SOME OF THESE COULD
AFFECT COASTAL TERMINALS. BY 18Z-20Z THE CONVECTION SHOULD SHIFT
WELL INLAND...WITH INTERIOR TERMINALS HAVING A CHANCE FOR STORMS
UNTIL 22-24Z.
&&
.MARINE...
TODAY-TONIGHT...EAST/NORTHEAST WINDS 5-10 KNOTS ARE FORECAST TO
BECOME NORTHEAST 10 KNOTS BY THIS AFTERNOON AND EVEN 10-15 KNOTS
OFFSHORE AS A SLIGHT SURGE OCCURS. SEAS WILL BE 2-3 FEET EXCEPT
3-4 FEET OFFSHORE AND PERIODS LOWERING TO 5-6 SECONDS WILL PRODUCE
MORE CHOP THAN WE HAVE HAD RECENTLY.
THE PRESSURE GRADIENT WILL WEAKEN OVERNIGHT WITH WINDS DROPPING
TO 5-10 KNOTS. THERE WILL BE SOME MARINE SHOWERS AND A FEW
STORMS...ESPECIALLY BUILDING SOUTHWARD TO THE WATERS AROUND
CANAVERAL THIS MORNING. LATEST RADAR TRENDS AND MODEL OUTPUT
SUGGEST THE SOUTHERN WATERS SHOULD HAVE MORE ISOLATED ACTIVITY.
MON-THU...THE PRESSURE GRADIENT WILL REMAIN FAIRLY WEAK WITH WIND
SPEEDS STILL FORECAST AOB 10 KTS ON AVERAGE. OVERNIGHT/MORNING WILL
LIKELY SEE AN OFFSHORE WIND COMPONENT DEVELOP WITH AN ONSHORE BREEZE
FORMING EACH AFTERNOON WITH SLOW PUSH INLAND. SHOWER/STORM CHANCES
STILL FAIRLY ISOLD MON/TUE BUT BEGIN TO PICK UP WED INTO THE
EXTENDED WITH OFFSHORE STEERING FLOW IN THE AFTERNOON/EVENING WED-
THU. SEAS STILL AOB 3 FT BUT LOCALLY HIGHER INVOF OF SHOWERS/STORMS.
BOATERS ON INLAND LAKES WILL AGAIN NEED TO KEEP AN EYE TO THE SKY IN
THE AFTERNOON/EARLY EVENING FOR DEVELOPING/APPROACHING
SHOWERS/STORMS AS PRECIPITATION CHANCES GO UP.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 74 92 74 / 30 10 20 20
MCO 93 75 94 75 / 40 10 30 20
MLB 91 76 92 75 / 30 10 20 10
VRB 90 74 91 74 / 30 10 10 10
LEE 94 76 94 77 / 40 10 30 20
SFB 93 75 94 76 / 40 10 30 20
ORL 93 76 95 77 / 40 10 30 20
FPR 91 74 92 74 / 30 10 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1030 AM EDT SUN AUG 23 2015
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 344 AM EDT SUN AUG 23 2015
SCATTERED THUNDERSTORMS WILL ACCOMPANY A STRONG COLD
FRONT LATER TODAY. THE FRONT WILL SHIFT EAST QUICKLY THIS
EVENING...WITH HIGH PRESSURE REESTABLISHING OVER THE OHIO VALLEY.
DRY AND PLEASANT WEATHER IS EXPECTED FOR THE ENTIRE WEEK AS THE HIGH
REMAINS THE DOMINANT WEATHER FEATURE.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 936 AM EDT SUN AUG 23 2015
FOCUS FOR TODAY IS THE APPROACH OF A COLD FRONT FROM THE WEST
LATER THIS AFTERNOON. SCATTERED CONVECTION WILL REFIRE ALONG THE
FRONT AS IT MOVES THROUGH THE FORECAST AREA DURING THE AFTERNOON.
THIN AXIS OF DEEPER MOISTURE WITH PRECIP WATER VALUES AROUND 1.50
INCHES WILL ADVECT INTO THE REGION IMMEDIATELY AHEAD OF THE
BOUNDARY. THE DEEPER MOISTURE WILL COMBINE WITH PEAK MLCAPE VALUES
AT 1000-1500 J/KG...LOW LEVEL CONVERGENCE AND BL SHEAR VALUES
BRIEFLY PEAKING NEAR 30KTS AS THE PRIMARY CATALYSTS IN CONVECTIVE
DEVELOPMENT DURING THE AFTERNOON.
THERE ARE MITIGATING FACTORS IN PLAY THOUGH HOWEVER. DESPITE
DIFFLUENCE ALOFT...STRONGER UPPER FORCING WILL REMAIN DISPLACED TO
THE NORTH OF THE AREA IN CLOSER PROXIMITY TO THE UPPER LOW. MODEL
SOUNDINGS FROM BOTH THE OP GFS AND THE RAP HINT AT A WEAK CAPPING
INVERSION PRESENT NEAR 10KFT WITH LARGELY POOR LAPSE RATES WHICH
WOULD LIMIT AVAILABLE INSTABILITY AND CONVECTIVE COVERAGE. NAM MODEL
SOUNDINGS PRESENT LITTLE IN THE WAY OF CAPPING AND CONSEQUENTLY
GREATER AVAILABLE INSTABILITY DURING THE AFTERNOON...BUT THIS
SOLUTION IS NOT PREFERRED AS CLOSER ANALYSIS INDICATES THAT IT IS
LIKELY OVERDOING BOTH SURFACE TEMPS AND DEWPOINTS LATER TODAY.
TAKING ALL OF THIS INTO ACCOUNT...HAVE TRENDED TOWARDS A CONSENSUS
SOLUTION LED BY THE HI RES SUITE OF THE HRRR...RAP AND WRF WHICH
BRING A NARROW YET BROKEN CONVECTIVE LINE QUICKLY ACROSS THE
FORECAST AREA PRIMARILY BETWEEN 18Z AND 00Z. HIGHEST POPS WILL BE
EMPLOYED OVER THE NORTHEAST HALF OF THE FORECAST AREA WHERE
INSTABILITY WILL BE GREATEST AND INTERACT WITH BEST SHEAR AND
MOISTURE. STORMS ARE LIKELY TO DISRUPT OUTDOOR ACTIVITIES
BRIEFLY...WITH GUSTY WINDS AND LIGHTNING...AND POSSIBLY HAIL.
STRONGER CELLS WILL HAVE THE POTENTIAL FOR AN ISOLATED SEVERE RISK
WITH DAMAGING WINDS AND LARGE HAIL...ESPECIALLY NORTH AND EAST OF
THE INDY METRO. STORMS WILL END RAPIDLY WITH THE FRONTAL PASSAGE BY
EARLY EVENING.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE FOR HIGHS CONSIDERING
INCREASING CLOUDS AND STORMS FOR THE AFTERNOON. EXPECTING GENERALLY
LOW TO MID 80S.
&&
.SHORT TERM /|TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 344 AM EDT SUN AUG 23 2015
FORECAST CHALLENGES ARE MINOR THROUGH THE SHORT TERM...AS STRONG
HIGH PRESSURE BUILDS IN WITH DRY...PLEASANT WEATHER THROUGH MIDWEEK.
HELD ONTO A LOW CHANCE POPS OVER FAR EASTERN COUNTIES FOR A FEW
HOURS THIS EVENING TO ACCOUNT FOR ANY LINGERING CONVECTION AS THE
COLD FRONT SWEEPS OFF TO THE EAST. EXPECT THE ENTIRE FORECAST AREA
WILL BE DRY BY 02-03Z AT THE LATEST.
STRONG UPPER LOW BY LATE AUGUST STANDARDS WILL PINWHEEL SLOWLY
THROUGH THE GREAT LAKES...MAINTAINING A BROAD TROUGH WITH COOL
CYCLONIC FLOW OVER THE REGION THROUGH MIDWEEK. EXPECT PLENTY OF
SUNSHINE BOTH MONDAY AND TUESDAY WITH DIURNAL AFTERNOON CU IN THE
COLD ADVECTION REGIME. CU WILL DISSIPATE NEAR SUNSET BOTH
DAYS...SETTING THE STAGE FOR MAINLY CLEAR SKIES AT NIGHT WITH COOL
TEMPERATURES. ALL IN ALL...A VERY PLEASANT STRETCH OF WEATHER
UPCOMING FOR MUCH OF THIS WEEK.
TEMPS...UTILIZED A MOS BLEND FOR HIGHS MONDAY...THEN TRENDED TOWARDS
WARMER MAVMOS GUIDANCE FOR TUESDAY. HIGHS WILL RUN ABOUT 5-10
DEGREES BELOW NORMAL BOTH DAYS IN THE 70S. SHOULD SEE A NICE RURAL-
URBAN SPLIT IN OVERNIGHT TEMPS WITH POTENTIAL FOR NORMAL COOL SPOTS
ACROSS THE FORECAST AREA TO FALL INTO THE 40S...ESPECIALLY
EARLY TUESDAY MORNING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 223 AM EDT SUN AUG 23 2015
GUIDANCE CONTINUES TO DEPICT A DRY AND COOL EXTENDED PORTION OF THE
FORECAST...ALTHOUGH WITH SOME MODERATION OF TEMPERATURES BACK TOWARD
NORMAL NEAR THE END OF THE PERIOD.
MODELS NOW SHOW A STRONGER SURFACE RIDGE ACROSS THE AREA LATE IN THE
WEEK...WHICH WOULD PREVENT FRONTAL ZONE FROM MAKING IT INTO THE AREA
UNTIL AFTER THE SEVEN DAY FORECAST PERIOD. CAN GO WITH A DRY
FORECAST THROUGHOUT THE EXTENDED.
BLENDED INITIALIZATION HANDLED THIS WELL AND ONLY MINOR TWEAKS WERE
REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 23/15Z KIND TAF UPDATE/...
ISSUED AT 1030 AM EDT SUN AUG 23 2015
MINOR TWEAKS MADE TO KIND TAF TO BETTER MATCH CURRENT CONDITIONS.
NO OTHER CHANGES ARE NEEDED AT THIS TIME.
PREVIOUS AVIATION DUSCUSSION FOLLOWS...
MAINLY VFR THROUGH THE PERIOD...ALTHOUGH MVFR OR WORSE COULD BRIEFLY
DEVELOP IN SHOWERS OR STORMS.
COLD FRONT WILL SWEEP ACROSS THE AREA LATER TODAY...AND SCATTERED
SHOWERS AND STORMS MAY DEVELOP ALONG IT. FOR NOW HAVE INSERTED VCSH
MENTION AND WILL ALLOW LATER PACKAGES TO REFINE AS DETAILS EMERGE.
BEST CHANCE FOR STORMS WOULD LIKELY BE IN 18-00Z TIME FRAME.
WINDS MAY GUST TO NEAR 20KT AT TIMES TODAY OUT OF THE SOUTHWEST.
OTHERWISE WINDS WILL BECOME LIGHT AND NORTHWESTERLY IN THE WAKE OF
THE FRONT THIS EVENING.
NO SIGNIFICANT OBSTRUCTIONS TO VISIBILITY OUTSIDE OF STORMS
ANTICIPATED DURING THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM...NIELD
AVIATION...NIELD/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
953 AM EDT SUN AUG 23 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 344 AM EDT SUN AUG 23 2015
SCATTERED THUNDERSTORMS WILL ACCOMPANY A STRONG COLD
FRONT LATER TODAY. THE FRONT WILL SHIFT EAST QUICKLY THIS
EVENING...WITH HIGH PRESSURE REESTABLISHING OVER THE OHIO VALLEY.
DRY AND PLEASANT WEATHER IS EXPECTED FOR THE ENTIRE WEEK AS THE HIGH
REMAINS THE DOMINANT WEATHER FEATURE.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 936 AM EDT SUN AUG 23 2015
FOCUS FOR TODAY IS THE APPROACH OF A COLD FRONT FROM THE WEST
LATER THIS AFTERNOON. SCATTERED CONVECTION WILL REFIRE ALONG THE
FRONT AS IT MOVES THROUGH THE FORECAST AREA DURING THE AFTERNOON.
THIN AXIS OF DEEPER MOISTURE WITH PRECIP WATER VALUES AROUND 1.50
INCHES WILL ADVECT INTO THE REGION IMMEDIATELY AHEAD OF THE
BOUNDARY. THE DEEPER MOISTURE WILL COMBINE WITH PEAK MLCAPE VALUES
AT 1000-1500 J/KG...LOW LEVEL CONVERGENCE AND BL SHEAR VALUES
BRIEFLY PEAKING NEAR 30KTS AS THE PRIMARY CATALYSTS IN CONVECTIVE
DEVELOPMENT DURING THE AFTERNOON.
THERE ARE MITIGATING FACTORS IN PLAY THOUGH HOWEVER. DESPITE
DIFFLUENCE ALOFT...STRONGER UPPER FORCING WILL REMAIN DISPLACED TO
THE NORTH OF THE AREA IN CLOSER PROXIMITY TO THE UPPER LOW. MODEL
SOUNDINGS FROM BOTH THE OP GFS AND THE RAP HINT AT A WEAK CAPPING
INVERSION PRESENT NEAR 10KFT WITH LARGELY POOR LAPSE RATES WHICH
WOULD LIMIT AVAILABLE INSTABILITY AND CONVECTIVE COVERAGE. NAM MODEL
SOUNDINGS PRESENT LITTLE IN THE WAY OF CAPPING AND CONSEQUENTLY
GREATER AVAILABLE INSTABILITY DURING THE AFTERNOON...BUT THIS
SOLUTION IS NOT PREFERRED AS CLOSER ANALYSIS INDICATES THAT IT IS
LIKELY OVERDOING BOTH SURFACE TEMPS AND DEWPOINTS LATER TODAY.
TAKING ALL OF THIS INTO ACCOUNT...HAVE TRENDED TOWARDS A CONSENSUS
SOLUTION LED BY THE HI RES SUITE OF THE HRRR...RAP AND WRF WHICH
BRING A NARROW YET BROKEN CONVECTIVE LINE QUICKLY ACROSS THE
FORECAST AREA PRIMARILY BETWEEN 18Z AND 00Z. HIGHEST POPS WILL BE
EMPLOYED OVER THE NORTHEAST HALF OF THE FORECAST AREA WHERE
INSTABILITY WILL BE GREATEST AND INTERACT WITH BEST SHEAR AND
MOISTURE. STORMS ARE LIKELY TO DISRUPT OUTDOOR ACTIVITIES
BRIEFLY...WITH GUSTY WINDS AND LIGHTNING...AND POSSIBLY HAIL.
STRONGER CELLS WILL HAVE THE POTENTIAL FOR AN ISOLATED SEVERE RISK
WITH DAMAGING WINDS AND LARGE HAIL...ESPECIALLY NORTH AND EAST OF
THE INDY METRO. STORMS WILL END RAPIDLY WITH THE FRONTAL PASSAGE BY
EARLY EVENING.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE FOR HIGHS CONSIDERING
INCREASING CLOUDS AND STORMS FOR THE AFTERNOON. EXPECTING GENERALLY
LOW TO MID 80S.
&&
.SHORT TERM /|TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 344 AM EDT SUN AUG 23 2015
FORECAST CHALLENGES ARE MINOR THROUGH THE SHORT TERM...AS STRONG
HIGH PRESSURE BUILDS IN WITH DRY...PLEASANT WEATHER THROUGH MIDWEEK.
HELD ONTO A LOW CHANCE POPS OVER FAR EASTERN COUNTIES FOR A FEW
HOURS THIS EVENING TO ACCOUNT FOR ANY LINGERING CONVECTION AS THE
COLD FRONT SWEEPS OFF TO THE EAST. EXPECT THE ENTIRE FORECAST AREA
WILL BE DRY BY 02-03Z AT THE LATEST.
STRONG UPPER LOW BY LATE AUGUST STANDARDS WILL PINWHEEL SLOWLY
THROUGH THE GREAT LAKES...MAINTAINING A BROAD TROUGH WITH COOL
CYCLONIC FLOW OVER THE REGION THROUGH MIDWEEK. EXPECT PLENTY OF
SUNSHINE BOTH MONDAY AND TUESDAY WITH DIURNAL AFTERNOON CU IN THE
COLD ADVECTION REGIME. CU WILL DISSIPATE NEAR SUNSET BOTH
DAYS...SETTING THE STAGE FOR MAINLY CLEAR SKIES AT NIGHT WITH COOL
TEMPERATURES. ALL IN ALL...A VERY PLEASANT STRETCH OF WEATHER
UPCOMING FOR MUCH OF THIS WEEK.
TEMPS...UTILIZED A MOS BLEND FOR HIGHS MONDAY...THEN TRENDED TOWARDS
WARMER MAVMOS GUIDANCE FOR TUESDAY. HIGHS WILL RUN ABOUT 5-10
DEGREES BELOW NORMAL BOTH DAYS IN THE 70S. SHOULD SEE A NICE RURAL-
URBAN SPLIT IN OVERNIGHT TEMPS WITH POTENTIAL FOR NORMAL COOL SPOTS
ACROSS THE FORECAST AREA TO FALL INTO THE 40S...ESPECIALLY
EARLY TUESDAY MORNING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 223 AM EDT SUN AUG 23 2015
GUIDANCE CONTINUES TO DEPICT A DRY AND COOL EXTENDED PORTION OF THE
FORECAST...ALTHOUGH WITH SOME MODERATION OF TEMPERATURES BACK TOWARD
NORMAL NEAR THE END OF THE PERIOD.
MODELS NOW SHOW A STRONGER SURFACE RIDGE ACROSS THE AREA LATE IN THE
WEEK...WHICH WOULD PREVENT FRONTAL ZONE FROM MAKING IT INTO THE AREA
UNTIL AFTER THE SEVEN DAY FORECAST PERIOD. CAN GO WITH A DRY
FORECAST THROUGHOUT THE EXTENDED.
BLENDED INITIALIZATION HANDLED THIS WELL AND ONLY MINOR TWEAKS WERE
REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 23/12Z TAFS/...
ISSUED AT 713 AM EDT SUN AUG 23 2015
MAINLY VFR THROUGH THE PERIOD...ALTHOUGH MVFR OR WORSE COULD BRIEFLY
DEVELOP IN SHOWERS OR STORMS.
COLD FRONT WILL SWEEP ACROSS THE AREA LATER TODAY...AND SCATTERED
SHOWERS AND STORMS MAY DEVELOP ALONG IT. FOR NOW HAVE INSERTED VCSH
MENTION AND WILL ALLOW LATER PACKAGES TO REFINE AS DETAILS EMERGE.
BEST CHANCE FOR STORMS WOULD LIKELY BE IN 18-00Z TIME FRAME.
WINDS MAY GUST TO NEAR 20KT AT TIMES TODAY OUT OF THE SOUTHWEST.
OTHERWISE WINDS WILL BECOME LIGHT AND NORTHWESTERLY IN THE WAKE OF
THE FRONT THIS EVENING.
NO SIGNIFICANT OBSTRUCTIONS TO VISIBILITY OUTSIDE OF STORMS
ANTICIPATED DURING THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM...NIELD
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
713 AM EDT SUN AUG 23 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 344 AM EDT SUN AUG 23 2015
SCATTERED THUNDERSTORMS WILL ACCOMPANY A STRONG COLD
FRONT LATER TODAY. THE FRONT WILL SHIFT EAST QUICKLY THIS
EVENING...WITH HIGH PRESSURE REESTABLISHING OVER THE OHIO VALLEY.
DRY AND PLEASANT WEATHER IS EXPECTED FOR THE ENTIRE WEEK AS THE HIGH
REMAINS THE DOMINANT WEATHER FEATURE.
&&
.NEAR TERM /TODAY/...
ISSUED AT 344 AM EDT SUN AUG 23 2015
ISOLATED SHOWERS HAVE DEVELOPED ACROSS THE WESTERN HALF OF THE
FORECAST AREA EARLY THIS MORNING AS A WEAK UPPER WAVE MOVES ACROSS
THE REGION. THE INCREASED CLOUD COVER ASSOCIATED WITH THE WAVE ALOFT
WAS KEEPING TEMPS WARMER THIS MORNING. 07Z TEMPS WERE LARGELY IN THE
60S.
THE INITIAL UPPER WAVE ACROSS THE AREA WILL SHIFT EAST PRIOR TO
DAYBREAK. COULD SEE ISOLATED SHOWERS OVER THE NEXT 2-3 HOURS BEFORE
AXIS OF DRIER AIR IMMEDIATELY BEHIND THE WAVE NOTED OFF WATER VAPOR
IMAGERY MOVES IN FROM THE WEST. SHOULD ALSO SEE A DECREASE IN CLOUDS
TOWARDS DAYBREAK WITH THE ARRIVAL OF THE DRIER AIR AS WELL.
THE FOCUS THEN TURNS TO THE APPROACH OF A COLD FRONT FROM THE WEST
LATER TODAY. CONVECTION ALONG THE BOUNDARY IS STEADILY WEAKENING
EARLY THIS MORNING OVER IOWA AND NORTHERN MISSOURI AND SHOULD
CONTINUE TO DO SO THROUGH SUNRISE AS THE STORMS MOVE INTO A LESS
FAVORABLE AIRMASS. MID AND HIGH LEVEL REMNANT CLOUD DEBRIS FROM
STORMS OVER THE MID MISSISSIPPI VALLEY WILL DRIFT INTO THE REGION
AFTER DAYBREAK...BUT EXPECT MOST AREAS WILL REMAIN DRY THROUGH
MIDDAY.
SCATTERED CONVECTION WILL REFIRE ALONG THE FRONT AS IT MOVES THROUGH
THE FORECAST AREA DURING THE AFTERNOON. THIN AXIS OF DEEPER MOISTURE
WITH PRECIP WATER VALUES AROUND 1.50 INCHES WILL ADVECT INTO THE
REGION IMMEDIATELY AHEAD OF THE BOUNDARY. THE DEEPER MOISTURE WILL
COMBINE WITH PEAK MLCAPE VALUES AT 1000-1500 J/KG...LOW LEVEL
CONVERGENCE AND BL SHEAR VALUES BRIEFLY PEAKING NEAR 30KTS AS THE
PRIMARY CATALYSTS IN CONVECTIVE DEVELOPMENT DURING THE AFTERNOON.
THERE ARE MITIGATING FACTORS IN PLAY THOUGH HOWEVER. DESPITE
DIFFLUENCE ALOFT...STRONGER UPPER FORCING WILL REMAIN DISPLACED TO
THE NORTH OF THE AREA IN CLOSER PROXIMITY TO THE UPPER LOW. MODEL
SOUNDINGS FROM BOTH THE OP GFS AND THE RAP HINT AT A WEAK CAPPING
INVERSION PRESENT NEAR 10KFT WITH LARGELY POOR LAPSE RATES WHICH
WOULD LIMIT AVAILABLE INSTABILITY AND CONVECTIVE COVERAGE. NAM MODEL
SOUNDINGS PRESENT LITTLE IN THE WAY OF CAPPING AND CONSEQUENTLY
GREATER AVAILABLE INSTABILITY DURING THE AFTERNOON...BUT THIS
SOLUTION IS NOT PREFERRED AS CLOSER ANALYSIS INDICATES THAT IT IS
LIKELY OVERDOING BOTH SURFACE TEMPS AND DEWPOINTS LATER TODAY.
TAKING ALL OF THIS INTO ACCOUNT...HAVE TRENDED TOWARDS A CONSENSUS
SOLUTION LED BY THE HI RES SUITE OF THE HRRR...RAP AND WRF WHICH
BRING A NARROW YET BROKEN CONVECTIVE LINE QUICKLY ACROSS THE
FORECAST AREA PRIMARILY BETWEEN 18Z AND 00Z. HIGHEST POPS WILL BE
EMPLOYED OVER THE NORTHEAST HALF OF THE FORECAST AREA WHERE
INSTABILITY WILL BE GREATEST AND INTERACT WITH BEST SHEAR AND
MOISTURE. STORMS ARE LIKELY TO DISRUPT OUTDOOR ACTIVITIES
BRIEFLY...WITH GUSTY WINDS AND LIGHTNING...AND POSSIBLY HAIL.
STRONGER CELLS WILL HAVE THE POTENTIAL FOR AN ISOLATED SEVERE RISK
WITH DAMAGING WINDS AND LARGE HAIL...ESPECIALLY NORTH AND EAST OF
THE INDY METRO. STORMS WILL END RAPIDLY WITH THE FRONTAL PASSAGE BY
EARLY EVENING.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE FOR HIGHS CONSIDERING
INCREASING CLOUDS AND STORMS FOR THE AFTERNOON. EXPECTING GENERALLY
LOW TO MID 80S.
&&
.SHORT TERM /|TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 344 AM EDT SUN AUG 23 2015
FORECAST CHALLENGES ARE MINOR THROUGH THE SHORT TERM...AS STRONG
HIGH PRESSURE BUILDS IN WITH DRY...PLEASANT WEATHER THROUGH MIDWEEK.
HELD ONTO A LOW CHANCE POPS OVER FAR EASTERN COUNTIES FOR A FEW
HOURS THIS EVENING TO ACCOUNT FOR ANY LINGERING CONVECTION AS THE
COLD FRONT SWEEPS OFF TO THE EAST. EXPECT THE ENTIRE FORECAST AREA
WILL BE DRY BY 02-03Z AT THE LATEST.
STRONG UPPER LOW BY LATE AUGUST STANDARDS WILL PINWHEEL SLOWLY
THROUGH THE GREAT LAKES...MAINTAINING A BROAD TROUGH WITH COOL
CYCLONIC FLOW OVER THE REGION THROUGH MIDWEEK. EXPECT PLENTY OF
SUNSHINE BOTH MONDAY AND TUESDAY WITH DIURNAL AFTERNOON CU IN THE
COLD ADVECTION REGIME. CU WILL DISSIPATE NEAR SUNSET BOTH
DAYS...SETTING THE STAGE FOR MAINLY CLEAR SKIES AT NIGHT WITH COOL
TEMPERATURES. ALL IN ALL...A VERY PLEASANT STRETCH OF WEATHER
UPCOMING FOR MUCH OF THIS WEEK.
TEMPS...UTILIZED A MOS BLEND FOR HIGHS MONDAY...THEN TRENDED TOWARDS
WARMER MAVMOS GUIDANCE FOR TUESDAY. HIGHS WILL RUN ABOUT 5-10
DEGREES BELOW NORMAL BOTH DAYS IN THE 70S. SHOULD SEE A NICE RURAL-
URBAN SPLIT IN OVERNIGHT TEMPS WITH POTENTIAL FOR NORMAL COOL SPOTS
ACROSS THE FORECAST AREA TO FALL INTO THE 40S...ESPECIALLY
EARLY TUESDAY MORNING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 223 AM EDT SUN AUG 23 2015
GUIDANCE CONTINUES TO DEPICT A DRY AND COOL EXTENDED PORTION OF THE
FORECAST...ALTHOUGH WITH SOME MODERATION OF TEMPERATURES BACK TOWARD
NORMAL NEAR THE END OF THE PERIOD.
MODELS NOW SHOW A STRONGER SURFACE RIDGE ACROSS THE AREA LATE IN THE
WEEK...WHICH WOULD PREVENT FRONTAL ZONE FROM MAKING IT INTO THE AREA
UNTIL AFTER THE SEVEN DAY FORECAST PERIOD. CAN GO WITH A DRY
FORECAST THROUGHOUT THE EXTENDED.
BLENDED INITIALIZATION HANDLED THIS WELL AND ONLY MINOR TWEAKS WERE
REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 23/12Z TAFS/...
ISSUED AT 713 AM EDT SUN AUG 23 2015
MAINLY VFR THROUGH THE PERIOD...ALTHOUGH MVFR OR WORSE COULD BRIEFLY
DEVELOP IN SHOWERS OR STORMS.
COLD FRONT WILL SWEEP ACROSS THE AREA LATER TODAY...AND SCATTERED
SHOWERS AND STORMS MAY DEVELOP ALONG IT. FOR NOW HAVE INSERTED VCSH
MENTION AND WILL ALLOW LATER PACKAGES TO REFINE AS DETAILS EMERGE.
BEST CHANCE FOR STORMS WOULD LIKELY BE IN 18-00Z TIME FRAME.
WINDS MAY GUST TO NEAR 20KT AT TIMES TODAY OUT OF THE SOUTHWEST.
OTHERWISE WINDS WILL BECOME LIGHT AND NORTHWESTERLY IN THE WAKE OF
THE FRONT THIS EVENING.
NO SIGNIFICANT OBSTRUCTIONS TO VISIBILITY OUTSIDE OF STORMS
ANTICIPATED DURING THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM...NIELD
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS GOODLAND KS
414 AM MDT SUN AUG 23 2015
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 406 AM MDT SUN AUG 23 2015
FORECAST CONCERNS WILL BE TEMPERATURES...AND LOW CHANCE FOR
PRECIPITATION AT THE END OF THIS PERIOD. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO NORTH AMERICA.
AT JET LEVEL..MODELS STARTED OUT FINE. AT MID LEVELS...THE MODELS
WERE CLOSE WITH THE GFS/CANADIAN DOING A LITTLE BETTER THAN THE
UKMET...NAM AND ECMWF. THE SREF WAS DOING A LITTLE BETTER THAN THE
ECMWF ON THE SURFACE WIND AND PRESSURE PATTERN. THE ECMWF WAS
DOING A LITTLE BETTER THAN THE CANADIAN...NAM AND GFS ON THE LOW
LEVEL THERMAL FIELD.
DESPITE CLOSE SOLUTIONS ALOFT FROM MONDAY INTO TUESDAY NIGHT...
MODELS HANDLE THE SURFACE PATTERN DIFFERENTLY WHICH DEPENDING ON
WHICH SOLUTION IS CORRECT COULD HAVE MAJOR AFFECTS ON THE FORECAST.
SO FORECAST CONFIDENCE IS BELOW AVERAGE DURING THIS TIME PERIOD.
TODAY/TONIGHT...INITIAL PROBLEM WILL BE TO SEE IF ANY NOCTURNAL
CONVECTION WILL BE AROUND IN THE MORNING. 00Z NAM WAS CATCHING THE
ISOLATED PRECIPITATION OVER THE WEST CENTRAL PORTION OF THE AREA
DURING THE MID AND LATE EVENING WITH A LITTLE LEFT OVER THE FAR
SOUTHERN PORTION AT 12Z. THE LATEST RAP WAS SHOWING THE SAME THING.
WILL CONTINUE TO WATCH TRENDS BUT IT DOES LOOK LIKE ALL THUNDERSTORMS
WILL BE SOUTH OF THE AREA AT THE BEGINNING OF THE DAY.
IT LOOKS LIKE WARM AIR ADVECTION ALOFT HAS SPREAD A THICKER MID DECK
OF CLOUD COVER OVER THE AREA. IT DOES LOOK LIKE THESE CLOUDS WILL
THEN OUT BY LATE MORNING. IF THEY CHOOSE TO HANG ON LONGER THEN
THE MAXES MAY BE IMPACTED. LIGHT AND VARIABLE TO LIGHT UPSLOPE
WINDS WILL TRANSITION TO A SOUTHERLY FLOW MAINLY OVER THE WESTERN
PORTION BY LATE IN THE AFTERNOON. MUCH COOLER AIR MASS AND
UNFAVORABLE WIND FIELD WILL MAKE FOR A COOL DAY WITH GUIDANCE IN
CLOSE AGREEMENT. LIGHT SOUTHERLY WINDS TONIGHT. AGAIN GUIDANCE
PRETTY CLOSE AND TENDED TO GO TOWARD THE COOLER GUIDANCE.
MONDAY/MONDAY NIGHT... MODELS DISAGREE ON HOW MUCH TO WARM UP THE
MAXES. SURFACE RIDGE WILL BE MOVING TO THE EAST WITH THE LEE TROUGH
DEVELOPING TO THE WEST. THERE SHOULD BE NO DOWNSLOPE COMPONENT TO
THE WINDS AND BELIEVE AT THIS TIME THAT THE WARMER GFS/MAV AND
CANADIAN ARE TOO WARM. TENDED TO GO IN THE MIDDLE OF THE TWO
EXTREMES.
THIS IS WHERE THE FORECAST STARTS GETTING MORE INTERESTING AND
UNCERTAIN. MODELS DISAGREE ON EXACTLY WHERE BUT THEY ALL INDICATE A
WEAK JET PROVIDING SOME LIFT ACROSS THE AREA FROM THE LATE EVENING
INTO THE OVERNIGHT HOURS. MODELS SHOW A SHORTWAVE TROUGH MOVING
ACROSS THE AREA AT THAT TIME WITH A DECENT BAROCLINIC ZONE ACROSS
THE EASTERN ZONES. MOISTURE DEFINITELY APPEARS TO BE A PROBLEM BUT
THERE LOOKS TO BE A LOT OF ELEVATED CAPE WITH THE ELEVATED CINH
POSSIBLY BEING OVERCOME. ONLY MODELS SHOWING SOME QPF ARE THE GFS
AND THE ENSEMBLE MEAN. AT THIS TIME WILL PUT IN A SLIGHT CHANCE OF
THUNDERSTORMS AFTER MIDNIGHT.
IN RETURN FLOW DURING THE NIGHT...THE 00Z NAM SHOWED AN INCREASE IN
BOUNDARY LAYER. THE 06Z NAM BACKED OFF THAT SOLUTION. WAS THINKING
OF PUTTING IN PATCHY FOG. BUT NOW WILL NOT AND WILL ONLY INCREASE
CLOUD COVER.
TUESDAY/TUESDAY NIGHT...WHATEVER STRATUS IS AROUND IS GONE BY LATE
MORNING. AT THIS TIME WILL LEAVE THE MENTION OF ANY THUNDERSTORMS
OUT DURING THE MORNING SINCE THIS IS UNCERTAIN AND IT LOOKS LIKE
WHAT LITTLE PRECIPITATION THERE IS WILL BE TO OUR EAST.
MODELS INDICATE THAT SOME KIND OF JET LIFT WILL BE AROUND THROUGH
THE ENTIRE DAY WITH SOME SHIFT TOWARD THE WESTERN PORTION OF THE
AREA LATE IN THE DAY. DURING THE NIGHT...SOME KIND OF JET
LIFT...MAINLY THE RIGHT REAR QUADRANT...MOVES FROM THE WESTERN AND
CENTRAL PORTION OF THE AREA IN THE EVENING INTO THE EASTERN PORTION
DURING THE OVERNIGHT HOURS.
AT THE SAME TIME THE MID LEVEL RIDGE BUILDS INTO THE AREA WITH RIDGE
ROUGHLY CENTERED OVER THE CENTRAL AND WESTERN PORTIONS OF OUR AREA.
MODELS WANT TO TRY TO PUSH A 700 MB SHORTWAVE INTO THE WESTERN
PORTION DURING THE AFTERNOON AND OVERNIGHT HOURS. BECAUSE A COUPLE
OF THE MODELS WANT TO PUT A BOUNDARY ACROSS THE CENTER OF OUR
AREA...UNDERNEATH A RIDGE WHICH DOES SEEM REASONABLE AT THIS
TIME...THOSE MODELS WANT TO PRODUCE PRECIPITATION OVER THE AREA. IF
ANY PRECIPITATION WOULD DEVELOP TO OUR WEST...NOT SURE HOW FAR EAST
IT WOULD GET DUE TO THE SLOW STORM MOTION.
IT IS A LITTLE DISCONCERTING THAT A NUMBER OF MODELS ARE PRODUCING
LIGHT QPF IN A SCENARIO WITH VERY LITTLE LIFT. SO AS NOT TOO WAFFLE
WILL KEEP THE THUNDERSTORMS OUT OF THE FORECAST BUT THIS PERIOD WILL
NEED TO BE LOOKED AT CLOSE AGAIN.
MODELS ARE ALL OVER THE PLACE WITH WHAT TO DO AT THE SURFACE. THE
GFS...CANADIAN AND TO A LESSER EXTENT THE ECMWF WANT TO DRAPE A
BOUNDARY ACROSS OUR AREA WITH EAST WINDS ACROSS A MAJORITY OF OUR
AREA. OTHER MODELS HAVE SOUTHEASTERLY WINDS. DID NOT WANT TO WARM UP
THINGS TOO MUCH...ESPECIALLY AS MUCH AS THE GFS/MAV WANTED TO
DO...WITH OTHER GUIDANCE COOLER. WENT TOWARD THAT COOLER GUIDANCE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 406 AM MDT SUN AUG 23 2015
WEST TO NORTHWEST FLOW ALOFT WILL CONTINUE AS THE UPPER LEVEL RIDGE
MOVES SOUTH AND WEST OF THE REGION IN THE BEGINNING OF THE EXTENDED
PERIOD. SHOWERS AND THUNDERSTORMS CANNOT BE RULED OUT WEDNESDAY
NIGHT THROUGH THE WEEKEND AS PERTURBATIONS MOVE ALONG THE RIDGE AND
THE HEIGHT FIELD APPEARS TO WEAKEN.
MODELS HAVE BEEN HINTING THAT A STRONGER WAVE WILL SLOWLY MOVE ALONG
THE PERIPHERY OF THE RIDGE FROM COLORADO/WYOMING SOUTHEAST INTO THE
HIGH PLAINS WEDNESDAY NIGHT THROUGH FRIDAY AS MOISTURE INCREASES.
THIS LOOKS TO GENERATE PRECIP CHANCES DURING THIS TIME FRAME WITH
THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS ON THURSDAY AND
THURSDAY NIGHT. MOSTLY DRY CONDITIONS RETURN IN TIME FOR THE WEEKEND
AS THE RIDGE MOVES EASTWARD TOWARDS THE PLAINS BEHIND THE
DISTURBANCE. STRENGTH OF THE RIDGE WILL DETERMINE IF THESE PRECIP
CHANCES HOLD UP AS THE PERIOD GETS CLOSER.
A DECREASE IN TEMPERATURES IS CURRENTLY EXPECTED WEDNESDAY THROUGH
THE END OF THE WORK WEEK WITH HIGHS IN THE LOW TO MID 80S ON FRIDAY
BEFORE INCREASING OVER THE WEEKEND. LOW TEMPERATURES WILL FOLLOW
SUITE...DROPPING INTO THE MID 50S TO LOW 60S BY FRIDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1129 PM MDT SAT AUG 22 2015
VISIBILITIES HAVE IMPROVED ACROSS THE CENTRAL HIGH PLAINS REGION
AS THE COLD FRONT MOVES FURTHER TO THE SOUTHEAST AND HIGH PRESSURE
CONTINUES TO PUSH IN AT THE SURFACE BEHIND THE COLD FRONT.
EXPECT CONDITIONS TO REMAIN VFR THROUGH THE TAF PERIOD AT MCK AND
GLD WITH SCATTERED LOW TO MID CLOUDS AND ISOLATED SHOWERS AND
THUNDERSTORMS TO MOVE ACROSS THE REGION MAINLY SOUTH OF THE TAF
SITES. EXPECT WINDS TO SLACKEN AND BECOME VARIABLE AS THE CENTER
OF THE SURFACE HIGH MOVES ACROSS THE REGION AROUND 18Z SUNDAY WITH
WINDS TURNING TO THE SOUTHEAST AND REMAINING LIGHT AS THE HIGH
MOVES INTO THE SOUTHERN PLAINS AND RETURN FLOW SETS UP ACROSS THE
CENTRAL HIGH PLAINS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...JBH
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS CARIBOU ME
951 AM EDT SUN AUG 23 2015
.SYNOPSIS...
THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS A WARM FRONT
TODAY THROUGH MONDAY. A SLOW MOVING FRONTAL SYSTEM IS EXPECTED
APPROACH THE REGION FROM THE WEST ON TUESDAY AND CROSS THE AREA ON
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
950 AM UPDATE...SHOWERS ARE HAVING A HARD TIME MAKING TOO ONSHORE
THIS MORNING, LIKELY DUE TO DRIER AIR NORTH OF THE SURFACE
BOUNDARY WHICH STILL LIES OFF THE COAST. HAVE SLOWED THE ARRIVAL
OF SHOWERS THIS MORNING ACCORDINGLY. HAVE ALSO MADE ADJUSTMENTS TO
HIGH TEMPERATURES ACROSS DOWNEAST AS SOME AREAS HAVE SEEN MORE SUN
THAN PREVIOUSLY EXPECTED, ALLOWING TEMPERATURES TO RISE MORE
QUICKLY. OTHERWISE THE FORECAST PRETTY MUCH REMAINS THE SAME.
PERVIOUS DISCUSSION...SURFACE ANALYSIS SHOWED TROF OR WEAK
FRONTAL BOUNDARY DRAPED ACROSS THE DOWNEAST REGION. THIS FEATURE
IS FORECAST TO LIFT NORTHWARD TODAY W/MORE HUMID AIR OVERSPREADING
THE REGION AS LOW PRES LIFTS NE ACROSS THE WESTERN ATLC. THE 00Z
NAM AND HRRR 3KM HAD THINGS INITIALIZED WELL. USED THIS BLEND FOR
TODAY`S FORECAST W/PRECIP LIFTING FROM S TO N.
SHOWERS WILL MOVE FROM S TO N TODAY. HIGH PRES ANCHORED OVER THE
NW ATLC WILL ACT AS A BLOCK INITIALLY AS PRECIP DIES OUT HITTING A
DRY AND STABLE AIRMASS IN PLACE ACROSS THE NORTH AND WEST. FURTHER
S ACROSS CENTRAL AND DOWNEAST AREAS, SOUNDING DATA SHOWED THE
COLUMN MOISTENING THROUGH 700MBS W/INCREASING INSTABILITY. SB
CAPES OF 500-1000 JOULES ARE FORECAST TO SETUP THIS AFTERNOON
ACROSS THE AFOREMENTIONED AREAS. PWATS ARE 1.7+ W/LIS DOWN TO -2
TO -3. 0-6KM SHEAR IS WEAK < 10 KTS. A WARM CLOUD LAYER W/HIGH
FREEZING LEVELS(13-14K FT) WILL LEAD TO LOADING OF PRECIP
W/POTENTIAL FOR HEAVY TO TORRENTIAL RAINFALL IN SPOTS. DECIDED TO
STAY W/TSTMS THIS AFTERNOON INTO THE EVENING AND ADDED HEAVY
RAINFALL WORDING.
SHOWERS AND SOME TSTMS ARE EXPECTED TO SPREAD INTO NORTHERN AND
WESTERN MAINE TONIGHT. SOUNDING DATA SHOWED MOST OF THE CONVECTION
TO BE ELEVATED W/THE HIGHEST THREAT ACROSS THE HOULTON AND
MILLINOCKET REGION W/LESS INSTABILITY FURTHER N. ONCE AGAIN HEAVY
RAIN THREAT CONTINUES. DOWNEAST AND COASTAL AREAS WILL BECOME MORE
STABLE W/FOG AND DRIZZLE. USED A CONSENSUS BLEND ON THE QPF DUE
TO LOW CONFIDENCE IN PLACEMENT OF HEAVIER RAINFALL AMOUNTS. SOME
AREAS COULD DEFINITELY PICK AN INCH OR MORE OF RAIN IN TSTMS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
UNSETTLED WX PATTERN CONTINUES FOR THE START OF THE WORK WEEK.
EXPECT THE CHANCE FOR SHOWERS AND AFTERNOON THUNDERSTORMS BOTH
MONDAY AND AGAIN ON TUESDAY AS A TROF OF LOW PRESSURE TRACKS
SLOWLY EAST FROM THE GREAT LAKES REGION. HIGH TEMPERATURES BOTH
MONDAY AND TUESDAY WILL RANGE FROM THE MID TO UPPER 70S. IT WILL
ALSO CONTINUE TO FEEL ON THE MUGGY SIDE WITH DEW POINT EXPECTED TO
REMAIN IN THE 60S BOTH DAYS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
TUESDAY NIGHT WILL SEE THE THREAT FOR SHOWERS AND EVENING
THUNDERSTORMS AS A LEAD SHORT WAVE AHEAD OF THE APPROACHING UPPER
TROF MOVES ACROSS THE REGION. UNSETTLED WEATHER WITH CONTINUED
CHANCES FOR SHOWERS AND AFTERNOON THUNDERSTORMS WILL CONTINUE INTO
THURSDAY EVENING AS THE TROF SWINGS ACROSS THE REGION. HIGH
PRESSURE WILL BUILD IN FOR FRIDAY. A COLD FRONT WILL CROSS THE
REGION SATURDAY.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: IFR/LIFR FOR SOME OF THE TERMINALS(KPQI-KHUL) THIS
MORNING DUE TO FOG. ACROSS KBGR AND KBHB, VFR ATTM. EXPECTING KBGR
AND KBHB TO DROP TO MVFR AND THEN IFR LATER THIS MORNING INTO THE
AFTERNOON AND HOLD AT IFR TONIGHT. THE NORTHERN TERMINALS WILL
IMPROVE TO VFR AFTER 12Z AND STAY THERE THROUGH THE AFTERNOON.
MVFR CONDITIONS ARRIVE ACROSS KHUL THIS EVENING AND THEN TO IFR BY
MIDNIGHT W/KPQI-KCAR-KFVE DROPPING TO MVFR BY LATE EVENING AND
THEN IFR OVERNIGHT. TSTMS W/CLOUD TO GROUND LIGHTNING AND HEAVY
RAINFALL ARE POSSIBLE THIS AFTERNOON INTO TONIGHT.
SHORT TERM: VFR CONDITIONS WILL PREVAIL MOST OF THE TIME BUT
MVFR/IFR IS POSSIBLE IN PATCHY NIGHTTIME/EARLY MORNING FOG AS WELL
AS SCT SHOWERS/TSTMS.
&&
.MARINE...
NEAR TERM: A 3 FOOT SWELLS OUT ON THE WATERS ATTM IS EXPECTED TO
BUILD TO AROUND 4 FT THIS AFTERNOON. SWELLS ARE EXPECTED TO BUILD
TO A RANGE OF 4-5 FT TONIGHT. WINDS WILL REMAIN LIGHT 10 KTS OR
LESS RIGHT INTO TONIGHT. FOG WILL HAMPER NAVIGATION FROM TIME TO
TIME. TSTMS ARE POSSIBLE LATER THIS AFTERNOON INTO THE EVENING.
SHORT TERM: WIND/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY
LEVEL.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HASTINGS/HEWITT/DUDA
MARINE...HASTINGS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
651 AM EDT SUN AUG 23 2015
.SYNOPSIS...
THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS A WARM FRONT
TODAY THROUGH MONDAY. A SLOW MOVING FRONTAL SYSTEM IS EXPECTED
APPROACH THE REGION FROM THE WEST ON TUESDAY AND CROSS THE AREA ON
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE...ADJUSTED THE POPS AND SHOWERS BACK BY A FEW HRS
THIS MORNING AS THE RADAR SHOWED SHOWERS MOVING IN FROM THE GULF
OF MAINE DISSIPATING AS THEY MOVE N. MORE SHOWERS BEGINNING TO
MAKE THEIR WAY TO THE COAST AND LOOK AS THOUGH THEY WILL HOLD
TOGETHER AS THEY MOVE INLAND. KEPT FOG IN A FEW HRS LONGER AS SOME OBS
SHOWED VSBYS DOWN 1SM OR LESS IN FOG. FOG SHOULD DISSIPATE AFTER
8 AM.
SURFACE ANALYSIS SHOWED TROF OR WEAK FRONTAL BOUNDARY DRAPED
ACROSS THE DOWNEAST REGION. THIS FEATURE IS FORECAST TO LIFT
NORTHWARD TODAY W/MORE HUMID AIR OVERSPREADING THE REGION AS LOW
PRES LIFTS NE ACROSS THE WESTERN ATLC. THE 00Z NAM AND HRRR 3KM
HAD THINGS INITIALIZED WELL. USED THIS BLEND FOR TODAY`S FORECAST
W/PRECIP LIFTING FROM S TO N.
SHOWERS WILL MOVE FROM S TO N TODAY. HIGH PRES ANCHORED OVER THE
NW ATLC WILL ACT AS A BLOCK INITIALLY AS PRECIP DIES OUT HITTING A
DRY AND STABLE AIRMASS IN PLACE ACROSS THE NORTH AND WEST. FURTHER
S ACROSS CENTRAL AND DOWNEAST AREAS, SOUNDING DATA SHOWED THE
COLUMN MOISTENING THROUGH 700MBS W/INCREASING INSTABILITY. SB
CAPES OF 500-1000 JOULES ARE FORECAST TO SETUP THIS AFTERNOON
ACROSS THE AFOREMENTIONED AREAS. PWATS ARE 1.7+ W/LIS DOWN TO -2
TO -3. 0-6KM SHEAR IS WEAK < 10 KTS. A WARM CLOUD LAYER W/HIGH
FREEZING LEVELS(13-14K FT) WILL LEAD TO LOADING OF PRECIP
W/POTENTIAL FOR HEAVY TO TORRENTIAL RAINFALL IN SPOTS. DECIDED TO
STAY W/TSTMS THIS AFTERNOON INTO THE EVENING AND ADDED HEAVY
RAINFALL WORDING.
SHOWERS AND SOME TSTMS ARE EXPECTED TO SPREAD INTO NORTHERN AND
WESTERN MAINE TONIGHT. SOUNDING DATA SHOWED MOST OF THE CONVECTION
TO BE ELEVATED W/THE HIGHEST THREAT ACROSS THE HOULTON AND
MILLINOCKET REGION W/LESS INSTABILITY FURTHER N. ONCE AGAIN HEAVY
RAIN THREAT CONTINUES. DOWNEAST AND COASTAL AREAS WILL BECOME MORE
STABLE W/FOG AND DRIZZLE. USED A CONSENSUS BLEND ON THE QPF DUE
TO LOW CONFIDENCE IN PLACEMENT OF HEAVIER RAINFALL AMOUNTS. SOME
AREAS COULD DEFINITELY PICK AN INCH OR MORE OF RAIN IN TSTMS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
UNSETTLED WX PATTERN CONTINUES FOR THE START OF THE WORK WEEK.
EXPECT THE CHANCE FOR SHOWERS AND AFTERNOON THUNDERSTORMS BOTH
MONDAY AND AGAIN ON TUESDAY AS A TROF OF LOW PRESSURE TRACKS
SLOWLY EAST FROM THE GREAT LAKES REGION. HIGH TEMPERATURES BOTH
MONDAY AND TUESDAY WILL RANGE FROM THE MID TO UPPER 70S. IT WILL
ALSO CONTINUE TO FEEL ON THE MUGGY SIDE WITH DEW POINT EXPECTED TO
REMAIN IN THE 60S BOTH DAYS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
TUESDAY NIGHT WILL SEE THE THREAT FOR SHOWERS AND EVENING
THUNDERSTORMS AS A LEAD SHORT WAVE AHEAD OF THE APPROACHING UPPER
TROF MOVES ACROSS THE REGION. UNSETTLED WEATHER WITH CONTINUED
CHANCES FOR SHOWERS AND AFTERNOON THUNDERSTORMS WILL CONTINUE INTO
THURSDAY EVENING AS THE TROF SWINGS ACROSS THE REGION. HIGH
PRESSURE WILL BUILD IN FOR FRIDAY. A COLD FRONT WILL CROSS THE
REGION SATURDAY.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: IFR/LIFR FOR SOME OF THE TERMINALS(KPQI-KHUL) THIS
MORNING DUE TO FOG. ACROSS KBGR AND KBHB, VFR ATTM. EXPECTING KBGR
AND KBHB TO DROP TO MVFR AND THEN IFR LATER THIS MORNING INTO THE
AFTERNOON AND HOLD AT IFR TONIGHT. THE NORTHERN TERMINALS WILL
IMPROVE TO VFR AFTER 12Z AND STAY THERE THROUGH THE AFTERNOON.
MVFR CONDITIONS ARRIVE ACROSS KHUL THIS EVENING AND THEN TO IFR BY
MIDNIGHT W/KPQI-KCAR-KFVE DROPPING TO MVFR BY LATE EVENING AND
THEN IFR OVERNIGHT. TSTMS W/CLOUD TO GROUND LIGHTNING AND HEAVY
RAINFALL ARE POSSIBLE THIS AFTERNOON INTO TONIGHT.
SHORT TERM: VFR CONDITIONS WILL PREVAIL MOST OF THE TIME BUT
MVFR/IFR IS POSSIBLE IN PATCHY NIGHTTIME/EARLY MORNING FOG AS WELL
AS SCT SHOWERS/TSTMS.
&&
.MARINE...
NEAR TERM: A 3 FOOT SWELLS OUT ON THE WATERS ATTM IS EXPECTED TO
BUILD TO AROUND 4 FT THIS AFTERNOON. SWELLS ARE EXPECTED TO BUILD
TO A RANGE OF 4-5 FT TONIGHT. WINDS WILL REMAIN LIGHT 10 KTS OR
LESS RIGHT INTO TONIGHT. FOG WILL HAMPER NAVIGATION FROM TIME TO
TIME. TSTMS ARE POSSIBLE LATER THIS AFTERNOON INTO THE EVENING.
SHORT TERM: WIND/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY
LEVEL.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1001 AM EDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 939 AM EDT SUN AUG 23 2015
COLD FRONT AND THUNDERSTORMS ASSOCIATED WITH THE FRONT IS MAKING
PROGRESS TO AND ACROSS LAKE MICHIGAN AT THE MOMENT. UPDATED THE
POPS TO SLOW THE TIMING DOWN JUST A BIT BASED ON THE RADAR TRENDS
AND THE HRRR WHICH SEEMED TO LINE UP PRETTY WELL AT 11Z WITH THE
CURRENT TRENDS. WILL CONTINUE TO UPDATE AGGRESSIVELY WITH THE
TIMING OVER THE NEXT FEW HOURS AS THE FRONT MOVES ACROSS THE
REGION. LATER HRRR RUNS SEEM TO GO ALONG AS WELL WITH THE CURRENT
RADAR TRENDS FROM KGRB AND KAPX. OTHERWISE, TEMPERATURES SEEM TO
BE FALLING ALONG WITH THE CURRENT THINKING.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 326 AM EDT SUN AUG 23 2015
HIGH IMPACT WEATHER: BAND OF SHOWERS AND STORMS. A FEW SEVERE
POSSIBLE.
SYNOPTIC PATTERN AND OBSERVATIONS:
EARLY MORNING ANALYSIS..A VERY IMPRESSIVE SHORTWAVE HAS CLOSED OFF
WHILE WORKING INTO MN. THE ASSOCIATED SFC LOW PRESSURE WAS FILLING
IN WESTERN ONTARIO...WITH A COLD FRONT DRAPED SOUTHWARD THROUGH NW
WISCONSIN AND IA. A BAND OF SHOWERS AND STORMS CONTINUES TO SLOWLY
PROGRESS EAST...WITHIN AXIS OF HIGH THETA-E AND SUPPORTED BY A SWATH
OF UPPER LEVEL DIVERGENCE IN A DOUBLE JET STRUCTURE. LAPSE RATES NOT
IMPRESSIVE...BUT DYNAMICAL FORCING IS ENOUGH TO CONTINUE STORMS INTO
THE NIGHT. ACROSS NRN MICHIGAN...AN EARLIER WING OF HIGHER THETA-E
AT 850MB HAS SLOWLY LIFTED NNE...WHILE A CORRIDOR OF DRIER/LOWER
THETA-E WAS WORKING INTO THE REGION. SKIES WERE CLEAR WITH ONLY SOME
THIN CIRRUS ENCROACHING. TEMPERATURES WERE IN THE 60S.
SYNOPTIC PATTERN EVOLUTION AND ASSOCIATED WEATHER:
QUITE A CHANGE IN THE WEATHER IS IN STORE. FIRST OFF...THE UPSTREAM
COLD FRONT WILL CROSS NRN MICHIGAN MID-LATE MORNING THROUGH EARLY
THIS EVENING. ONE VORTICITY MAX WILL LIFT NE INTO THE WESTERN CWA
THIS MORNING...AND ANOTHER THIS AFTERNOON...ROUNDING THE BASE OF THE
CLOSED/NEGATIVELY TILTED UPPER TROUGH. WE DO GET INTO SOME UPPER
DIVERGENCE WITH A LEFT FRONT EXIT REGION...OF A JET ON THE SRN
PERIPHERY OF THE UPPER TROUGH...BUT FORCING MAINLY APPLIED BY DPVA
AND LOW LEVEL CONVERGENCE. LAPSE RATES ARE LESS THAN DESIRABLE AT
5.5 TO 6.0 C/KM. SFC BASED DEW POINTS WILL ONLY BE IN THE MIDDLE 50S
WITHIN THE DRIER AIR/SWATH OF LOWER THETA-E AIR...BUT DEW POINTS
WILL POOL IN THE LOWER HALF OF THE 60S ALONG THE FRONT WHICH ARRIVES
MID-LATE MORNING ACROSS THE WESTERN CWA...AND THIS AFTERNOON ACROSS
NE LOWER. HEATING WILL BE DIFFICULT TO COME BY IN THE WESTERN
CWA...WITH CLOUDS INCREASING TOO EARLY FOR MUCH HEATING WHERE HIGHS
WILL BE IN THE LOWER 70S. ACROSS NE LOWER...SUNSHINE WILL BE ABLE TO
WARM TEMPERATURES INTO THE UPPER 70S AROUND 80F. BY THE TIME THE
FRONT ARRIVES WITH THE BETTER LOW LEVEL MOISTURE...CAPE WILL BE IN
THE 800-1200 J/KM RANGE. NOT OVERLAY FANTASTIC...AND 0-6 KM BULK
SHEAR WITH THE STORMS WILL BE MARGINAL FOR ANY ORGANIZED
CONVECTION...25-30KTS. ALL-IN-ALL...A FEW STORMS MAY BE ABLE TO
BECOME SEVERE...MAINLY M-32 SOUTH AND MOSTLY EAST OF I-75. DAMAGING
WINDS THE MAIN THREAT...BUT STRONGER CELLS WILL BE ABLE TO PRODUCE
AT LEAST SOME HAIL.
BEHIND THE FRONT...SOME SCATTERED SHOWERS ARE LIKELY...BUT DEEPER
MOISTURE STRIPS OUT WITH A POSSIBLE A PERIOD OF CLEARING. COOLER LOW
LEVEL AIR AND DEEPER LOWER LEVEL MOISTURE ADVECTION THROUGH THE
NIGHT. THE DEEPEST MOISTURE WILL REMAIN TO OUR NW...BUT WE HAVE
ENOUGH OVERNIGHT TO COMBINE WITH H8 TEMPS CRASHING INTO THE SINGLE
DIGITS FOR THE DEVELOPMENT OF LAKE EFFECT RAIN SHOWERS. NOT ONLY
THAT...BUT THE INSTABILITY DEEPENS OVER THE LAKES (500-700 J/KG) AND
THERE WILL BE AT LEAST A CHANCE FOR A RUMBLE OF THUNDER OR TWO. THIS
WILL PRIMARILY BE WSW FLOW REGIMES...ACROSS FAR NW LOWER...THROUGH
THE STRAITS...AND OVER TO DRUMMOND ISLAND.
HIGHS WILL RANGE FROM THE LOWER 70S WEST TO THE UPPER 70S EAST. LOWS
TONIGHT GENERALLY IN THE MIDDLE 50S AND GUSTY ALONG THE LAKE
MICHIGAN COAST.
&&
.SHORT TERM...(MONDAY THROUGH TUESDAY NIGHT)
ISSUED AT 326 AM EDT SUN AUG 23 2015
HIGH IMPACT WEATHER POTENTIAL: BESIDES JUST BEING DOWNRIGHT CHILLY
MONDAY AND TUESDAY...STILL MONITORING WATERSPOUT POTENTIAL FOR BOTH
THESE DAYS (WHICH WILL BE COVERED IN THE MARINE SECTION TO FOLLOW).
PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: PATTERN GETTING SET TO
BECOME QUITE THE AMPLIFIED ONE...WITH MAIN PLAYER DRIVING SUCH
AMPLIFICATION BEING STRONG UPPER JET CORE/ATTENDANT MID LEVEL WAVE
DIGGING INTO THE UPPER MISSISSIPPI VALLEY EARLY THIS MORNING. THIS
SYSTEM WILL HELP CARVE OUT AN ANOMALOUSLY DEEP (FOR THE TIME OF YEAR
AT LEAST) AND CHILLY MID LEVEL LOW...WHICH WILL CENTER ITSELF RIGHT
OVER THE NORTHERN LAKES AND SOUTHERN CANADA THROUGH AT LEAST THE
FIRST HALF OF THIS UPCOMING WORK WEEK.
PRIMARY FORECAST CONCERNS/CHALLENGES: ADDRESSING MULTIPLE PERIODS OF
LAKE ENHANCED SHOWERS. TEMPERATURE TRENDS THROUGH THE FORECAST.
ADDRESSING WATERSPOUT POTENTIAL.
DETAILS: UPPER LEVEL LOW...CHECK. COOL TEMPERATURES...CHECK. GUSTY
WINDS...CHECK. LAKE ENHANCED RAIN SHOWERS...CHECK. YUP...IT ALL ADDS
UP...OCTOBER WEATHER HERE IN THE END OF AUGUST. THAT`S MONDAY`S AND
TUESDAY`S WEATHER FOLKS...AND EVEN A COOL WEATHER FAN LIKE MYSELF
HAS TO SAY ITS NOT LOOKING PLEASANT. BLAME IT ALL ON THAT CURRENT
MINNESOTA WAVE...WITH IT AND A NICE UPPER LEVEL COUPLED JET HELPING
CARVE OUT THAT DEEP LOW MENTIONED EARLIER. DEEP CYCLONIC FLOW AROUND
IT...COUPLED WITH EXCELLENT LOW LEVEL MOISTURE AND PERIODS OF UPWARD
QG SUPPORT WILL BE MORE THAN ENOUGH TO KICK OFF SOME SHOWERS. ADD IN
INCREASING LAKE MOISTURE CONTRIBUTION AS H8 TEMPS FALL INTO THE MID
SINGLE DIGITS AND DIURNALLY DRIVEN ENHANCEMENT AWAY FROM THE
LAKES...AND NUMEROUS TO WIDESPREAD SHOWERS APPEARS A PRETTY GOOD
BET. DAYTIME FORECASTER TRENDED TOWARD THIS MORE WET LOOKING
SCENARIO...AND SIMPLY SEE NO REASON TO DEVIATE FROM IT. IT IS NOT
COMPLETELY OUT OF THE QUESTION FOR SOME LAKE PRODUCED THUNDERSTORMS
...PARTICULARLY MONDAY AND MONDAY EVENING WHEN NAM-WRF BUFKIT
SOUNDINGS SHOW IN EXCESS OF 500 J/KG OF LAKE INDUCED CAPE AND
EQUILIBRIUM LEVELS OVER 20 KFT. IF STORMS DO FORM...SOME SMALL HAIL
IS INDEED POSSIBLE WITH WET BULB ZERO HEIGHTS AT ONLY ABOUT 6KFT.
AS MENTIONED...IT`S GONNA BE DOWNRIGHT CHILLY FOR AUGUST...WITH
CLOUDS...SHOWERS...AND AN UNSEASONABLY COOL AIRMASS KEEPING HIGHS
MOSTLY IN THE 60S. AS HAS BEEN MENTIONED THE LAST FEW DAYS...COULD
EASILY SEE PARTS OF EASTERN UPPER AND THE HIGHLAND OF NORTHERN LOWER
FAILING TO BREAK 60 DEGREES...ESPECIALLY ON TUESDAY. IT REALLY WON`T
MATTER...WITH PRETTY GUSTY WINDS MAKING IT FEEL IN THE 50S ACROSS
MUCH OF THE AREA.
&&
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT SUN AUG 23 2015
WHILE SLOWLY WANING...TROUGHING AND COOL WEATHER CONTINUE TO
DOMINATE HEADING RIGHT INTO WEDNESDAY. LAKE PROCESSES WILL
CONTINUE...ALTHOUGH SLOWLY WEAKENING WITH TIME AS COLD CORE
ANOMALIES RELAX AND FORCING DEPARTS. ANY BREAK LATER WEDNESDAY
NIGHT AND THURSDAY WILL BE SHORT- LIVED AS FAST MOVING WAVE DIVES
THROUGH NORTHWEST FLOW ALOFT...WITH IT AND ITS ATTENDANT COLD
FRONT RETURNING A SHOWER THREAT FRIDAY INTO THE START OF SATURDAY.
WHILE NOT NEAR AS COOL AS EARLIER IN THE WEEK... TEMPERATURES WILL
CONTINUE TO RUN AT LEAST A FEW DEGREES BELOW NORMAL.
MARINE...STILL CONCERNED ABOUT WATERSPOUT POTENTIAL...ESPECIALLY
LATER MONDAY INTO MONDAY NIGHT WHEN LAKE-INDUCED CAPE IS
MAXIMIZED...PERHAPS EXCEEDING 500 J/KG WITH EQUILIBRIUM LEVELS UP
NEAR 20KFT. WHILE THIS MAY BE A TOUCH AGGRESSIVE...WITH DEEP
TROUGHING AND SEVERAL WAVES/SURFACE TROUGHS TO ENHANCE
CONVERGENCE...GOTTA BELIEVE THERE IS SOME POTENTIAL. WILL NOT
INTRODUCE THIS WORDING TO THE OFFICIAL FORECAST JUST YET...USING THE
LATEST HAZARDOUS WEATHER OUTLOOK TO EXPRESS THIS CONCERN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 641 AM EDT SUN AUG 23 2015
...BAND OF SHOWERS WITH A FEW STORMS AND PERIODS OF MVFR ON THE
WAY...
A WEDGE OF DRY AIR OVER THE REGION WILL ALLOW FOR A SUNNY START TO
THE DAY. A COLD FRONT THEN PUSHES THROUGH NRN MICHIGAN THROUGH
THE DAY BRINGING A BAND OF SHOWERS AND A HANDFUL OF STORMS...A
FEW OF WHICH HAVE A SLIGHT CHANCE OF BECOMING SEVERE ACROSS APN.
THE PRIMARY THREAT IS DAMAGING WINDS...SOME STRONGER CELLS COULD
PRODUCE SOME HAIL. THIS BAND ARRIVES IN NW LOWER LATE THIS
MORNING...AND ACROSS APN LATE AFTERNOON/EARLY EVENING. PERIODS OF
MVFR CIGS AND POSSIBLY VSBY WILL ACCOMPANY THE BAND OF
SHOWERS...AS WILL ALSO BE POSSIBLE IN THE COOL AIR BEHIND THE
FRONT. CONTINUED COOLING TONIGHT WILL BRING THE DEVELOPMENT OF
LAKE EFFECT RAIN SHOWERS TO PLN.
S/SW WINDS WILL BE GUSTY INITIALLY AHEAD OF THE FRONT...LONGEST
PERIOD OF GUSTINESS ACROSS APN. GUSTS MAY DISAPPEAR FOR AWHILE
WITHIN THE BAND OF RAIN...BUT WILL PICK UP AGAIN BEHIND THE FRONT
OUT OF THE W/NW. THIS GUSTY CONDITION WILL CONTINUE ACROSS NW
LOWER THROUGH TONIGHT.
&&
.MARINE...
ISSUED AT 326 AM EDT SUN AUG 23 2015
SOUTHERLY WINDS ARE INCREASING ACROSS THE LAKES AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE REGION TODAY AND THIS
EVENING. ADVISORY LEVEL GUSTS ARE EXPECTED AT ALL NEARSHORES...BUT
AS WE REMAIN IN A TIGHT GRADIENT BEHIND THE FRONT...IN STRONG COLD
ADVECTION...ADVISORY LEVEL GUSTS ARE A BETTER BET. THE FRONT WILL
BRING A BAND OF SHOWERS AND STORMS...SOME OF WHICH MAY BE STRONG
WITH SOME GUSTY WINDS AND HAIL. STRONG COLD ADVECTION CONTINUES INTO
MONDAY WITH LAKE EFFECT RAIN SHOWERS (AND A FEW RUMBLES OF THUNDER
AGAIN POSSIBLE). OTHER ISSUES COME ABOUT...LIKE THE NEED TO MONITOR
FOR POSSIBLE WATERSPOUTS...ESPECIALLY LATER MONDAY THROUGH TUESDAY.
SIMPLE PATTERN RECOGNITION OF ANOMALOUSLY DEEP MID AND UPPER LEVEL
LOW CENTERED NEARBY THIS TIME OF YEAR SURE SUPPORTS SUCH. EARLY
INDICATIONS OF SEVERAL VORT LOBES/ATTENDANT SURFACE TROUGHS ROTATING
AROUND PARENT CIRCULATION...FURTHER ENHANCING LOW LEVEL CONVERGENCE.
LAKE INDUCED EQUILIBRIUM LEVELS SOARING TO OVER 20 KFT DURING THIS
PERIOD...WHICH FAVORS UPPER LEVEL LOW ASSOCIATED WATERSPOUTS PER THE
SZILAGYI WATERSPOUT NOMOGRAM. WILL STILL NOT SPECIFICALLY INTRODUCE
THIS POTENTIAL IN THE FORECAST...BUT VERY WELL MAY NEED TO IN LATER
FORECASTS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ008-015-016-
019>021-025-031.
LH...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LSZ321-322.
&&
$$
UPDATE...JSL
NEAR TERM...SMD
SHORT TERM...MSB
LONG TERM...MSB
AVIATION...SMD
MARINE...SMD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT SUN AUG 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EDT SUN AUG 23 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW POTENT SHRTWV/
CUTOFF H5 LO DRIFTING INTO WRN MN. THIS DISTURBANCE CAUSED 12Z-24Z
H5/H3 HGT FALLS OF 150M/220M AT BISMARCK. SHARPLY DIFFLUENT UPR
FLOW/AREA OF DPVA AND SHARP DEEP LYR QVECTOR CNVGC IN ADVANCE OF
THIS FEATURE AND OVER ATTENDANT COLD FNT/WARM CONVEYOR BELT MSTR
RIBBON /00Z PWAT 1.50 INCH TO AS HI AS 1.93 INCH AT INL WITHIN THIS
MSTR BAND/ IS SUPPORTING BAND OF SCT-NMRS SHOWERS/TS STRETCHING FM
THE MN ARROWHEAD/ADJOINING ONTARIO THRU WRN LK SUP INTO THE MID MS
RIVER VALLEY. THE 00Z GRB RAOB WAS RELATIVELY DRY AND CAPPED...SO
THE WX OVER UPR MI IN ADVANCE OF THE FNT/SHOWERS HAS BEEN RELATIVELY
QUIET EXCEPT FOR GUSTY S WINDS UNDER THE TIGHT PRES GRADIENT BTWN
RETREATING HI PRES OVER THE NE STATES AND 995MB SFC LO DRIFTING NEWD
IN NW ONTARIO. AS THE SHOWERS HAVE MOVED E TOWARD UPR MI INTO
THIS MORE STABLE AIRMASS IN THE PRESENCE OF NOCTURNAL COOLING...THE
LTG INTENSITY HAS DIMINISHED. LOOKING FARTHER TO THE W...A WELL
DEFINED DRY SLOT HAS ENDED THE PCPN FARTHER W IN MN...BUT MORE
SHOWERS AND EVEN A FEW TS ARE EVIDENT OVER THE DAKOTAS MOVING INTO
FAR WRN MN UNDER SHARP COMMA HEAD CLD MASS ASSOCIATED WITH THE
SHRTWV.
MAIN FCST CONCERNS TODAY WL BE ON TIMING/COVERAGE OF WARM CONVEYOR
BELT SHOWERS/TS AND THEN WRAP ARND MSTR/SHOWERS TNGT AS CUTOFF LO IN
MN DRIFTS TO THE E AND OVER NRN LK SUP BY 12Z MON. STRONG WNW WINDS
WL IMPACT MAINLY THE WRN ZNS LATE TODAY/TNGT UNDER THE TIGHTER PRES
GRADIENT ON THE SW FLANK OF DEEP SFC LO PRES STACKED UNDER THE
CLOSED UPR LO.
TODAY...AS CLOSED/STACKED LO DRIFTS TO JUST NW OF THUNDER BAY BY
00Z...SFC COLD FNT IS FCST TO REACH IWD BY 12Z...CENTRAL UPR MI BY
18Z AND THEN NEWBERRY BY 00Z. AREA OF DPVA/DEEP LYR QVECTOR CNVGC
AND SHARP UPR DVGC IN LEFT EXIT OF SUPPORTING H3 JET MAX MOVING E ON
THE SRN FLANK OF THE CLOSED LO OVER THE WARM CONVEYOR BELT MSTR
RIBBON AHEAD OF THE FNT SHOULD SUPPORT RELATIVELY NARROW BAND OF
NMRS SHOWERS. EXPECT THESE SHOWERS...WITH SOME EMBEDDED TS
MAINTAINED BY HEALTHY DYNAMIC FORCING DESPITE MODEST MUCAPE NO MORE
THAN 200-400 J/KG...TO SWING W-E ACRS THE CWA WITH THE FNT. ARRIVAL
OF DRY SLOTTING BEHIND THE FROPA/WARM CONVEYOR BELT WL BRING A QUICK
DIMINISHING TREND TO THE PCPN. SOME PREVIOUS MODELS HAD SUGGESTED
DAYTIME HEATING IN THE PRESENCE OF LINGERING DEEP LYR QVECTOR CNVGC
WITHIN THE DRY SLOT MIGHT RESULT IN MORE INSTABILITY SHOWERS/TS...
BUT FCST SDNGS NOW INDICATE THE DRYING WL BE TOO OVERWHELMING. AREA
OF BACKWASH MSTR UNDER CYC W FLOW NOW PUSHING INTO WRN MN WL THEN
OVERSPREAD THE W HALF. AS H85 TEMPS FALL TOWARD 5-6C OVER THE W BY
00Z IN THE STRONG LLVL CAA...LLVL LAPSE RATES WL INCRS AND ALLOW FOR
EXTENSIVE SC/SOME SHOWERS/MORE EFFICIENT MIXING OF 30-35KT H925 W
WINDS TO THE SFC. TEMPS ARE LIKELY TO FALL THIS AFTN OVER THE W WITH
THE CAA/CLDY SKIES.
TNGT...THE CLOSED/STACKED LO IS FCST TO DRIFT SLOWLY SE AND OVER NRN
LK SUP BY 12Z MON. THE TIGHTER PRES GRADIENT/H925 W WINDS UP TO 30-
35KTS UNDER THE H85 THERMAL TROF ON THE SW FLANK OF THE SFC LO ARE
FCST TO IMPACT MAINLY THE W AND SCENTRAL CWA AND RESULT IN SOME
GUSTY WINDS...ESPECIALLY AT EXPOSED LOCATIONS NEAR LK SUP. H85 TEMPS
AS LO AS 2-4C /WATER TEMPS OVER WRN LK SUP ARE AS HI AS 15-17C/
ADVECTING INTO THE FAR W WL SUPPORT SOME LK EFFECT SHOWERS OVER
MAINLY THE HIER TERRAIN OF THE NW HALF.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 312 AM EDT SUN AUG 23 2015
THE NEARLY VERTICALLY STACKED SURFACE AND UPPER LOW AT 12Z MONDAY
WILL BE SLOWLY MOVING EAST ACROSS NORTHERN ONTARIO AND WILL CONTINUE
THAT PATH THROUGH TUESDAY NIGHT BEFORE FINALLY BECOMING CAUGHT UP IN
THE NORTHERN STREAM FLOW AND QUICKLY LIFTING NORTHEAST THROUGH
QUEBEC ON WEDNESDAY/THURSDAY. THIS WILL LEAD TO A VERY FALL LIKE
START TO THE WORK WEEK WITH BREEZY WEST-NORTHWEST WINDS...PERIODS OF
LAKE EFFECT/ENHANCED RAIN AND TEMPERATURES WELL BELOW NORMAL.
WITH ABUNDANT MOISTURE WRAPPING AROUND THE UPPER/SURFACE
LOW...EXPECT PLENTY OF LOW CLOUDS (AND SCATTERED TO NUMEROUS
SHOWERS) ACROSS THE U.P. FOR MONDAY INTO AT LEAST WEDNESDAY MORNING.
THE MAIN QUESTION WILL BE HOW COLD THE 850MB TEMPS WILL BE TO THE
SOUTHWEST OF THE LOW IN ONTARIO. MODELS VARY IN THE EXACT
VALUE...WITH THE NAM THE COLDEST AT 0-1C AND THE REST IN THE 2.5-4C
RANGE FOR MONDAY AND THEN GRADUALLY WARMING THROUGH TUESDAY. THE
EXACT VALUE DOESN/T MATTER TOO MUCH...AS THE TEMPERATURES ALOFT WILL
BE COLD ENOUGH FOR LAKE ENHANCED/EFFECT RAIN WITH WESTERN LAKE
SUPERIOR TEMPERATURES AROUND 15-17C. THEREFORE...WILL SHOW LIKELY TO
DEFINITE VALUES FOR THE FAVORED WEST-NORTHWEST WIND AREAS ON MONDAY
AND TRANSITION TO MORE NORTHWESTERLY FOR MONDAY NIGHT INTO TUESDAY.
IN ADDITION...WILL HAVE THE HIGHEST POPS OVER THE FAVORED UPSLOPE
LOCATIONS FOR THE MONDAY INTO TUESDAY PERIOD (AREAS FROM THE SPINE
OF THE KEWEENAW THROUGH IRONWOOD). THAT UPSLOPE FORCING WILL BE DUE
TO THE WEST-NORTHWEST WINDS ON MONDAY AND THEN TRANSITION TO MORE
NORTHWESTERLY ON MONDAY NIGHT AS THE SURFACE-850MB LOW SHIFTS EAST
AND CLOSER TO JAMES BAY AND THE SURFACE TROUGH MOVES EAST ACROSS THE
UPPER GREAT LAKES. THAT NORTHWESTERLY LOW LEVEL FLOW WILL CONTINUE
INTO WEDNESDAY...POTENTIALLY TURNING A LITTLE MORE NORTH-NORTHWEST.
THE STRONGEST WINDS WILL OCCUR MONDAY INTO MONDAY NIGHT (GUSTS OF 20-
30KTS OVER THE WESTERN U.P.) WITH THE TIGHTEST PRESSURE GRADIENT AS
THE SURFACE LOW IS JUST TO THE NORTH OF LAKE SUPERIOR. THEN THE
WINDS WILL GRADUALLY DIMINISH TUESDAY INTO WEDNESDAY AS THE LOW
WEAKENS/BROADENS AS IT MOVES INTO NORTHEAST ONTARIO.
THE THIRD ITEM OF NOTE TO START THE WEEK WILL BE THE VERY FALL LIKE
HIGHS ACROSS THE AREA ON MONDAY. WITH PLENTY OF CLOUDS AND
SHOWERS...HAVE OPTED TO FOLLOW THE RAW MODELS FOR HIGHS ON
MONDAY...WHICH GIVES LOW-MID 50S OVER THE WEST AND MID-UPPER 50S
OVER THE EAST. THIS IS ABOUT 20 DEGREES BELOW NORMAL AND IN SOME
AREAS THEY WILL BE NEARING RECORD COLD HIGH TEMPERATURES. THE RECORD
FOR OUR OFFICE IS 56 DEGREES (1978/1971) AND WE WILL BE NEAR THAT
BOTH AT MIDNIGHT TONIGHT AND AGAIN WITH THE HIGH ON MONDAY
AFTERNOON. LOOKING AT THE TIME SHIFTED COOP DATA (NEED TO USE 8/25
VALUES)...MANY SITES HAVE RECORD VALUES IN THE 50S AND SOME OF THE
MORE NOTABLE ONES ARE...IRONWOOD 55 IN 1915...HOUGHTON 53 IN 1987
(MIDNIGHT-MIDNIGHT)...IRON MOUNTAIN 59 IN 1940...MUNISING 57 IN
1940...AND 55 IN NEWBERRY IN 1917. THUS...WITH THE GOING FORECAST
HIGH TEMPERATURES...THERE WILL BE SEVERAL SPOTS THAT WILL BE NEAR
RECORD LOW MAXIMUM VALUES. TEMPERATURES WILL WARM A FEW DEGREES FOR
TUESDAY...BUT HIGHS WILL STILL BE IN THE UPPER 50S AND LOWER 60S.
DRY AIR FROM THE HIGH BUILDING INTO THE PLAINS ON WEDNESDAY WILL
FINALLY BRING AN END TO THE PROLONGED PERIOD OF CLOUDS AND SHOWERS
FROM WEST TO EAST ON WEDNESDAY (ALTHOUGH THE CLOUDS MAY LINGER OVER
THE FAR EAST INTO THE EVENING HOURS). THAT HIGH PRESSURE RIDGE WILL
MOVE OVER THE AREA WEDNESDAY NIGHT AND REMAIN INTO THURSDAY.
CLEARING SKIES AND LIGHT WINDS ON WEDNESDAY NIGHT WILL LEAD TO A
GOOD RADIATIONAL COOLING NIGHT ACROSS THE AREA AND HAVE LOWER LOWS
SOME FROM THE PREVIOUS FORECAST (CLOSER TO THE MEX AND GEM VALUES
WHICH TEND TO PERFORM BETTER IN THOSE SITUATIONS). ABUNDANT SUNSHINE
ON THURSDAY WILL LEAD TO HIGHS RETURNING TO MORE NORMAL VALUES FOR
LATE AUGUST.
FINALLY...A COLD FRONT WILL DROP SOUTHEAST ACROSS THE UPPER GREAT
LAKES LATE THURSDAY NIGHT INTO FRIDAY...BRINGING A CHANCE FOR
SHOWERS/THUNDERSTORMS TO THE U.P.. THINK THE COVERAGE/AMOUNTS WILL
LIMITED DUE TO THE LACK OF RETURN FLOW AND EXISTING DRY AIR.
THUS...WON/T GO MORE THAN LOW CHANCE POPS FOR NOW AS THE FRONT MOVES
THROUGH. A WEAK RIDGE LOOKS TO MOVE OVER THE AREA FOR SATURDAY
BEHIND THE FRONT AND SHOULD LEAD TO A DRY DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 727 AM EDT SUN AUG 23 2015
A BAND OF SHOWERS/PERHAPS AN EMBEDDED TS AHEAD OF A COLD FNT WL
RESULT IN A PERIOD OF MVFR CIGS TO CMX AND SAW THIS MRNG BEFORE
SURGE OF DRY AIR AHEAD OF VIGOROUS SHRTWV APRCHG FM THE W ALLOWS FOR
A PERIOD OF VFR CONDITIONS THAT WL BE MOVING INTO IWD AT TAF
ISSUANCE. BUT AREA OF MOISTER LLVL AIR MOVING E THRU MN WL BRING A
RETURN OF MVFR CIGS THIS AFTN AT IWD AND THEN CMX WITH INCRSG
UPSLOPE W WIND ARND DEEP LO PRES IN NW ONTARIO. GUSTY W WINDS AND
MVFR CONDITIONS WL DOMINATE IWD/CMX TNGT. DOWNSLOPE NATURE OF THIS
FLOW AT SAW SUGGESTS VFR WX WL PREDOMINATE THERE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 312 AM EDT SUN AUG 23 2015
A FALL LIKE LOW PRESSURE SYSTEM CURRENTLY TO THE NORTH OF THE LAKE
OF THE WOODS WILL BRING WINDY CONDITIONS TO LAKE SUPERIOR THROUGH
THE FIRST HALF OF THE UPCOMING WORK WEEK AS IT SLOWLY MOVES EAST
ACROSS NORTHERN ONTARIO. GUSTY SOUTHERLY WINDS WILL CONTINUE THIS
MORNING AHEAD OF A COLD FRONT OVER WESTERN LAKE SUPERIOR...BUT AS
IT MOVES EAST ACROSS THE REST OF THE LAKE TODAY IT WILL SHIFT WINDS
TO THE WEST AND LEAD TO GALES TO 35 KNOTS FOR PORTIONS OF WESTERN
LAKE SUPERIOR THIS AFTERNOON AND EXPANDING ACROSS THE REST OF
THE WESTERN HALF OF THE LAKE TONIGHT AND CONTINUING INTO MONDAY.
WITH THE LOW SLOWLY WEAKENING MONDAY NIGHT INTO TUESDAY AS IT NEARS
JAMES BAY...THE WINDS WILL GRADUALLY DIMINISH AND TURN TO THE
NORTHWEST. HIGH PRESSURE WILL BUILD OVER THE UPPER GREAT LAKES
REGION FOR WEDNESDAY AND THURSDAY..WHICH WILL LOWER WINDS BELOW
20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 2 PM EDT /1 PM CDT/ THIS AFTERNOON TO 8 PM EDT
/7 PM CDT/ MONDAY FOR LSZ162-263-264.
GALE WARNING FROM 2 AM TO 8 PM EDT MONDAY FOR LSZ265.
GALE WARNING FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO 5 PM EDT
/4 PM CDT/ MONDAY FOR LSZ240>244.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
919 AM CDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 918 AM CDT SUN AUG 23 2015
MINOR UPDATE TO INCREASE POPS/QPF AND ADJUST HOURLY AND MAX TEMPS
DOWN SLIGHTLY TO BETTER MATCH TRENDS. AREA OF SHOWERS HAS EXPANDED
OVER MN ZONES IN THE PAST FEW HOURS...SO HAVE INCREASED POPS OVER
THOSE AREAS. THINK SCATTERED VERY LIGHT SHOWERS WILL AFFECT NW WI
TOO...SO NUDGED POPS UP THERE AS WELL. TOOK QPF A LITTLE HIGHER...
ESPECIALLY THROUGH 18Z TO BETTER ACCOUNT FOR RADAR TRENDS. TEMPS
WERE NOT RECOVERING AS QUICKLY AS GOING FORECAST SUGGESTED...SO
TAMPED TEMPS DOWN AND CLOSER TO HRRR GUIDANCE.
UPDATE ISSUED AT 638 AM CDT SUN AUG 23 2015
UPDATED FOR THE NEW 12Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT SUN AUG 23 2015
THE STRONG SURFACE LOW OVER NORTHWEST ONTARIO WITH A COLD FRONT
EXTENDING SOUTH ACROSS THE FORECAST AREA AND DOWN INTO WESTERN
WISCONSIN AND INTO IOWA. A TROUGH AXIS ALSO EXTENDS DOWN INTO THE
RED RIVER VALLEY TO EASTERN SOUTH DAKOTA. ABOVE THIS...A TROWAL
EXTENDS INTO NORTHERN MINNESOTA WITH AN AREA OF SHOWERS AND SOME
THUNDERSTORMS. THE ASSOCIATED UPPER LOW IS OVER NORTHERN MINNESOTA.
THIS WHOLE SYSTEM WILL MOVE SLOWLY NORTHEAST TODAY AND
TONIGHT...BECOMING MORE STACKED WITH TIME AND MORE CUT OFF AT UPPER
LEVELS. THIS IS GOING TO LEAVE US WITH CYCLONIC FLOW AND PLENTY OF
SHOWERS AND CLOUD COVER. THE TROWAL IS GOING TO ROTATE ACROSS THE
NORTHERN FORECAST AREA TODAY...AND EVEN THIS EVENING BEFORE
WEAKENING OVERNIGHT. HAVE KEPT POPS HIGHEST ALONG THE NORTHERN
BORDER CLOSEST TO THE SURFACE LOW AND UNDER THE TROWAL...BUT TAPER
OFF TO DRY OR SLIGHT CHANCE TO THE SOUTH. THIS IS ALSO GOING TO
KEEP TEMPERATURES VERY COOL...WITH HIGHS ONLY IN THE UPPER 50S NORTH
TO LOW 60S SOUTH. THEN...TONIGHT THE CLOUD COVER IS GOING TO PULL
EAST SOME...AND ALONG WITH THE STRONG COLD AIR ADVECTION ALLOW
TEMPERATURES TO DROP INTO THE 40S OVERNIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 347 AM CDT SUN AUG 23 2015
A DEEP AREA OF LOW PRESSURE NORTH OF LAKE SUPERIOR WILL GRADUALLY
SHIFT INTO FAR NE ONTARIO FROM MONDAY MORNING THROUGH TUESDAY...THEN
HEAD INTO WESTERN QUEBEC ON WEDNESDAY. THIS LOW WILL CONTINUE TO
BRING THE NORTHLAND A PROLONGED PERIOD OF COOL AND BREEZY NORTHERLY
FLOW FOR THE EARLY PART OF THE WEEK...BUT WITH A TRANSITION TO SUNNY
AND SEASONABLY WARM WEATHER BY WEDNESDAY WHEN HIGH PRESSURE MOVES
INTO THE REGION. THIS WILL BRING A GRADUAL DAILY WARMING TREND INTO
THE MIDDLE OF THE WEEK...WITH HIGHS OF 10 TO 15 DEGREES BELOW NORMAL
ON MONDAY BECOMING NEAR NORMAL BY WEDNESDAY.
ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED OVER THE NORTHERN
AND EASTERN FORECAST AREA FOR MONDAY DUE TO THE DAYTIME HEATING AND
RESULTING LOW LEVEL LAPSE RATES. SHOWERS ARE ALSO POSSIBLE
TUESDAY...BUT MAINLY OVER THE ARROWHEAD.
SOUTHERLY RETURN FLOW WILL DEVELOP THURSDAY...CONTINUING THE WARMING
TREND. SUNNY SKIES AND THE SOUTHERLY BREEZE SHOULD ALLOW HIGHS TO
REACH SLIGHTLY ABOVE NORMAL. A SHORTWAVE TROUGH PASSAGE COULD BRING
SHOWERS AND STORMS LATE THURSDAY INTO FRIDAY.
THE MODELS ARE LACKING AGREEMENT FOR THE END OF THE WEEK. THE GFS
HAS A WARM FRONT NEAR THE SOUTHERN FORECAST AREA AND ASSOCIATED PCPN
FOR FRIDAY NIGHT AND SATURDAY...WHILE THE ECMWF HAS SURFACE HIGH
PRESSURE OVER MINNESOTA AND WISCONSIN WITH MOSTLY DRY WEATHER FOR
THE NORTHLAND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 638 AM CDT SUN AUG 23 2015
GUSTY WNW WINDS...IFR/MVFR CEILINGS...AND RAINS SHOWERS WILL
DEVELOP THIS MORNING AS AN UPPER LEVEL LOW OVER FAR NORTHERN
MINNESOTA LIFTS INTO NW ONTARIO. THE CEILINGS SHOULD LIFT FOR MOST
TERMINALS WITH A TRANSITION BACK TO VFR BY LATER THIS AFTERNOON.
HOWEVER...KINL WILL LIKELY REMAIN MVFR. WIND GUSTS COULD EXCEED 35
KNOTS THIS AFTERNOON AND EVENING AS COOL AIR POURS OUT OF
CANADA.
THE CEILINGS WILL LIKELY LOWER AGAIN TONIGHT BACK TO MVFR.
HOWEVER...KBRD WILL LIKELY CLEAR TO VFR. THE CEILINGS WILL INHIBIT
RADIATIONAL COOLING...AND COULD HELP MAINTAIN THE GUSTY WINDS WELL
INTO THE EVENING. WHEREAS THE WINDS SHOULD SIGNIFICANTLY WEAKEN AT
KBRD DUE TO THE CLEARING SKIES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 61 48 58 48 / 90 50 20 20
INL 59 43 56 45 / 90 80 30 0
BRD 63 49 66 48 / 60 10 0 0
HYR 62 48 60 47 / 50 20 10 0
ASX 65 48 59 51 / 60 30 20 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT MONDAY FOR LSZ121-140>148.
&&
$$
UPDATE...HUYCK
SHORT TERM...LE
LONG TERM...GROCHOCINSKI
AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
649 AM CDT SUN AUG 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT SUN AUG 23 2015
MOST OF THE FORECAST SHIFT WAS SPENT TRYING TO BUILD IN DETAILS ON
THE TRENDS IN THE WEATHER FROM THE STRONG CYCLONE OVER THE
NORTHERN PART OF THE REGION. OVERALL...DIDNT GET THE STRENGTH OF
STORMS OUT OF THE SYSTEM...AND MARGINAL WIND SHEAR AT BEST AND
THIN INSTABILITY TONGUE HAD MUCH TO DO WITH THAT.
GOES WATER VAPOR SHOWING THE VIGOROUS SHORTWAVE TROUGH EJECTING
E-NE TOWARD KDLH AT 07Z WITH DEFORMATION PRECIPITATION SEEN ACROSS
ND IN REGIONAL RADARS. LOCALLY...THE COLD FRONT IS PUSHING TOWARD
ERN WI WITH LIGHT SHRA AHEAD OF THE FRONT AND SOME POST-FRONTAL
SHRA ABOUT A COUNTY FURTHER WEST. MULTIPLE FRONTOGENETIC BANDS
INDICATED IN THE RAP IN THE LOWER LEVELS. THESE WILL CONTINUE EAST
AND OUT OF THE FORECAST AREA DURING THE EARLY MORNING HOURS.
CLOUDS AND LOW-LEVEL SECONDARY TROUGH/FRONTAL AXIS ALONG
MN/DAKOTAS BORDER IS SHIFTING TOWARD THE AREA AS WELL. AS THE
SURFACE LOW SHIFTS EAST THROUGH SOUTHERN MANITOBA TODAY AND
FILLS...MANY OF THE FORCING FEATURES WEAKEN...INCLUDING THE
MN TROUGH AXIS AND CONVERGENCE ALONG IT. THE SYSTEM BECOMES A
BROAD CYCLONIC FLOW SCENARIO WITH ONLY A WEAK REMNANT TROUGH
AFFECTING NRN WI LATER THIS MORNING AND AFTERNOON. HAVE BROUGHT
SOME ISO-SCT SHRA BACK IN ALONG AND NORTH OF I-94 FOR MAINLY THE
17-22Z WINDOW. THERE IS SOME SUGGESTION IN THE HI-RES MODELS THAT
THIS COULD ALSO AFFECT CENTRAL WI. HAVE ALSO CONTINUED AFTERNOON
WIND GUSTS OF 25-35 MPH...REMAINING BELOW WIND ADVISORY CRITERIA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN AUG 23 2015
CONFIDENCE IS ABOVE AVERAGE THROUGH THURSDAY WITH QUIET WEATHER
EXPECTED AND BELOW NORMAL TEMPERATURES. ALONG AND NORTH OF I-94
TEMPERATURES WILL BE MUCH BELOW NORMAL. MONDAY WILL BE THE
COLDEST DAY BEFORE MODERATION SLOWLY OCCURS...ESPECIALLY WEDNESDAY
ON. HAVE LOWERED THE TEMPERATURES IN THE NORTH DOWN A NOTCH INTO
THE UPPER 50S FOR HIGHS MONDAY AS THE COLD AIR POCKET SLIPS
THROUGH UNDER THICK CLOUDS.
ON MONDAY..MAY HAVE TO TREND TOWARD HIGHER SHRA CHANCES NORTHEAST OF
I-94 MONDAY AFTERNOON DEPENDING ON THE TRACK OF WELL AGREED UPON
SHORTWAVE TROUGH ENERGY. THIS WAVE IS ACTUALLY THE CURRENT MN
VORTEX ROTATING AROUND THE LONGER WAVE TROUGH AND BACK IN FROM THE
NORTH MONDAY. CURRENTLY THE TRACK APPEARS TO FAVOR NORTHEASTERN WI
FOR SHRA...BUT WILL KEEP WATCH AS DIURNAL TIMING IS IDEAL FOR
ENHANCED SHRA COVERAGE. MONDAY AGAIN WILL SEE GUSTY NORTHWEST
WINDS OF 25-30 MPH IN THE AFTERNOON.
RIDGE BUILDING THEN BEGINS AND DOMINATES THROUGH THURSDAY.
SOME DIFFERENCES SHOW UP FRIDAY AND INTO SATURDAY. SOME RETURN
FLOW WARMING OCCURS AND THE GFS IS MORE AGGRESSIVE WITH RIDGE
BUILDING OVER THE NORTHERN CONUS. THE 23.00Z CANADIAN/ECMWF AND
21.18Z DGEX SOLUTIONS ARE AT ODDS WITH THE 23.00Z GFS...AS THEY
ALL HAVE A CUTOFF LOW DRIFTING E/SE THROUGH NEB/IA LATE IN THE
WEEK. HOWEVER...THE 23.00Z GEFS DOES HAVE SOME MEMBERS THAT PICK
UP ON THE LOW AS WELL...SO IT LOOKS LIKE THAT MAY BE A BETTER
SOLUTION FOR LATE WEEK. THIS WOULD BRING SOME RAIN CHANCES
POSSIBLY CLOSE OR INTO THE AREA. WILL HAVE TO LET THIS ALL SHAKE
OUT...AND WENT WITH CONSENSUS BLEND WHICH TURNS INTO SLIGHT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 648 AM CDT SUN AUG 23 2015
AN UPPER LEVEL WILL MOVE NORTHEAST ACROSS NORTHERN MINNESOTA AND
WESTERN ONTARIO THROUGH TONIGHT. THIS LOW WILL PRODUCE A BROKEN
DECK OF MVFR CLOUDS THROUGH EARLY AFTERNOON...AND A 3 TO 5K DECK
OF CLOUDS FROM MID AFTERNOON INTO THE EVENING AT THE TAF SITES.
A TIGHT PRESSURE GRADIENT WILL PRODUCE SUSTAINED WEST WINDS OF
15 TO 25 KNOTS...AND WIND GUSTS IN THE 25 TO 35 KNOT RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATE
NWS TUCSON AZ
1150 AM MST SUN AUG 23 2015
.SYNOPSIS...CONDITIONS ARE STILL FAVORABLE FOR AN INCREASE IN THE
STRENGTH AND COVERAGE OF STORMS LATER TODAY AND MONDAY...ALTHOUGH
SOME VALLEY DEVELOPMENT WILL BE DELAYED. SOME STORMS WILL GENERATE
STRONG WINDS AND HEAVY RAIN. THE INCREASED MOISTURE WILL ALSO KEEP
DAYTIME TEMPERATURES CLOSER TO SEASONAL AVERAGES. FOR THE SECOND
HALF OF THE NEW WEEK...BUILDING HIGH PRESSURE WILL TEND TO SUPPRESS
THUNDERSTORM COVERAGE WHILE BRINGING HOTTER TEMPERATURES TO THE AREA.
&&
.UPDATE...THE 18Z SOUNDING HAS MAINTAINED A NICE WIND PROFILE WITH
DECENT STORM LEVEL FLOW AND BETTER SHEAR THAN RECENT DAYS. SIGNS OF
RECOVERY COMPARED TO 12Z WITH MODIFIED MIXED LAYER CAPE PUSHING 800
AND CONVECTIVE INHIBITION FALLING TO SLIGHTLY MORE MANAGEABLE
LEVELS. WHILE WE PROBABLY WON`T REACH CONVECTIVE INITIATION VERY
EASILY IN VALLEY LOCATIONS THE SOUNDING APPEARS TO BE RESPONSIVE
ENOUGH TO OUTFLOWS. OUR CURRENT FORECAST WILL STAND PAT WITH THE
IDEA OF SLOWER VALLEY DEVELOPMENT LARGELY DEPENDENT ON VIGOROUS
ORGANIZED OUTFLOW FROM THE EAST AND NORTHEAST. STILL LOOKING FOR
DUST BECOMING AN ISSUE WITH FAVORED AREAS MAINLY IN PINAL COUNTY AND
NORTHERN PORTIONS OF THE TOHONO O`ODHAM NATION. FORECAST UPDATE OUT
SHORTLY WILL FURTHER REDUCE THE CHANCE OF VALLEY STORMS IN THE
AFTERNOON HOURS FOR MANY LOCATIONS.
&&
.DISCUSSION...THE 12Z KTWC SOUNDING IS A BIT WORKED OVER AS
EXPECTED. CURRENT THINKING IS THAT IT WILL RECOVER ENOUGH FOR STRONG
EASTERLY/NORTHEASTERLY OUTFLOW TO FIRE CONVECTION ACROSS METRO
TUCSON AGAIN LATE IN THE AFTERNOON OR EARLY EVENING. WE WILL SEE HOW
THE ATMOSPHERE IS PROGRESSING WITH AN 18Z RELEASE IN A LITTLE WHILE.
LATEST HRRR CONTINUES TO BACK-PEDAL ON STORM CHANCES TODAY WHILE THE
12Z STANDARD GFS/NAM RUNS WERE MORE FAVORABLE SUSTAINING DEEP
OUTFLOW FROM THE EAST INTO LOWER DESERT LOCATIONS DURING LATE
AFTERNOON AND EVENING HOURS. THIS REMAINS OUR CURRENT FORECAST
SCENARIO PENDING THE PROGRESS REPORT FROM THE 18Z SOUNDING.
WE`RE ALSO LOOKING AT THE ORIENTATION OF THE EXPECTED OUTFLOWS FROM
CONVECTION IN EASTERN AREAS FOR POSSIBLE LARGE SCALE BLOWING DUST
CONCERNS...ESPECIALLY IN PINAL COUNTY.
PLEASE SEE THE PREVIOUS DISCUSSION FOR ADDITIONAL DETAILS.
&&
.AVIATION...VALID THRU 24/18Z.
MAINLY W OF KTUS...FEW-SCTD 8-12KFT OTRW CLR. FROM KTUS S AND E...
SCTD TO LCLY BKN CLOUDS AT 8-12K FT. AFT 23/19Z ISOLD TO SCTD
-SHRA/TS. AFT 24/00Z SCT-BKN 8-10K FT AREA WIDE WITH BKN LYRS ABV
AND SCT SHRA/TSRA. BRIEF MVFR CONDS...ALONG WITH STRONG GUSTY WINDS
POSSIBLE IN AN AROUND SHRA/TSRA. WINDS AWAY FROM STORMS GENERALLY
LIGHT AND TERRAIN DRIVEN. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...GOOD THUNDERSTORM CHANCES LATER TODAY WELL INTO
TONIGHT THEN AGAIN MONDAY AS A DISTURBANCE MOVES NW ACROSS THE
REGION. DECENT STORM CHANCES REMAIN TUESDAY INTO WEDNESDAY DUE TO
PLENTY OF MOISTURE LINGERING OVER THE REGION. AN UPPER RIDGE WILL
BUILD OVER THE AREA LATE IN THE WEEK INTO NEXT WEEKEND RESULTING IN
A SIGNIFICANT DECREASE IN SHOWER AND THUNDERSTORMS AND TEMPERATURES
RISING TO NEAR RECORD LEVELS FRIDAY ONWARD. OUTSIDE OF THUNDERSTORM
WINDS...WINDS WILL BE TYPICAL FOR MID AUGUST AND GENERALLY LESS THAN
15 MPH WITH AFTERNOON GUSTINESS.
&&
.DISCUSSION...WATER VAPOR IMAGERY...23/00Z UPPER-AIR PLOTS AND
LATEST MODEL DATA INDICATE THAT HIGH PRESSURE EXTENDS GENERALLY FROM
SRN CALIFORNIA/NRN BAJA ACROSS THE DESERT SOUTHWEST AND INTO NEW
MEXICO. TROUBLE WITH UPPER-AIR BALLOON LAUNCHES YESTERDAY AFTERNOON
RESULTED IN NO FLIGHT FOR KTWC AND A SHORT FLIGHT FROM KPSR (ONLY UP
TO AROUND 620MB)...SO NO PW INFO FROM THAT SOURCE. HOWEVER...THE U
OF A GPS PW VALUES SHOW AROUND 1.2 INCHES FOR TUS AND SIMILAR VALUES
FROM THE SATELLITE DERIVED BLENDED TOTAL PW IMAGERY. IR SATELLITE
IMAGERY SHOWS LINGERING CONVECTION WELL TO OUR EAST OVER SOUTH
CENTRAL NEW MEXICO...WITH MID TO HIGH LEVEL DEBRIS CLOUDS EXTENDING
WESTWARD INTO SOUTHEAST ARIZONA AS FAR AS THE TUCSON AREA. THESE
CLOUDS SHOW SIGNS OF ERODING.
MODELS INDICATE THAT THE HIGH SHIFTS TO A POSITION THAT EXTENDS FROM
ARIZONA THROUGH NEW MEXICO AND INTO EASTERN TEXAS TODAY. AS THIS
OCCURS FLOW WILL BECOME EAST TO SOUTHEAST WITH A WEAK DISTURBANCE
PROGGED TO MOVE ACROSS NORTHERN CHIHUAHUA MEXICO AND ACROSS THE
ARIZONA/SONORAN BORDER THIS AFTERNOON THROUGH LATE MONDAY AS IT
MOVES TOWARD THE LOWER COLORADO RIVER BASIN. MODELS ARE ADVERTISING
THE PW`S TO INCREASE TO AROUND 1.4-1.6 INCHES TODAY FOR TUCSON WITH
LESSER VALUES EAST. BY MONDAY VALUES EXPECTED TO RANGE FROM 1.2-1.4
INCHES EAST...1.5-1.6 INCHES CENTRAL AREAS AND 1.8-2.0 INCHES FOR
THE FAR WEST (AJO/ORGAN PIPE). WITH THE COMBO OF AMPLE MOISTURE AND
THE AFOREMENTIONED TRIGGERING MECHANISM OF THE WEAK VORT MAX
TRAVERSING SOUTHERN ARIZONA...EXPECT SCATTERED TO LOCALLY NUMEROUS
SHOWERS AND THUNDERSTORMS TODAY THROUGH MONDAY...WITH THE BEST
THREAT OCCURRING LATE THIS AFTERNOON AND THIS EVENING...BUT STILL A
DECENT THREAT AGAIN MONDAY AFTERNOON/EVENING.
BY TUESDAY RAIN CHANCES IN THE LOW END SCATTERED CATEGORY NEARLY
AREA WIDE AS THE WEAK DISTURBANCE MOVES UP THE COLORADO RIVER VALLEY
AS THE HIGH SHIFTS TO A POSITION OVER EASTERN COLORADO. SO...
WITHOUT THAT ENHANCEMENT STILL STORMS AROUND...BUT NOT AS NUMEROUS
AS WHAT IS EXPECTED FOR TODAY AND MONDAY.
BY WEDNESDAY THE HIGH IS EXPECTED TO MOVE TO NEW MEXICO/WEST TEXAS
WITH PW`S EXPECTED TO BE DOWN FROM PREVIOUS DAYS...GENERALLY IN THE
1.1 TO 1.4 INCH RANGE FOR EAST AND CENTRAL LOCATIONS.
FOR THURSDAY AND CONTINUING THROUGH SATURDAY...THE HIGH IS EXPECTED
TO SHIFT TO A POSITION NEARLY OVERHEAD OR JUST TO OUR SOUTH...GIVING
US A DRIER SOUTHWESTERLY FLOW ALOFT...WITH PW`S DROPPING TO AROUND
THE 1 INCH MARK BY SATURDAY. THAT SAID...I TWEAKED THE POP FORECAST
FOR LATE IN THE PERIOD TO GIVE US MAINLY ISOLATED TO LOW END
SCATTERED ACTIVITY MAINLY NEAR THE NEW MEXICO BORDER FOR FRIDAY AND
SATURDAY.
FOR TUCSON...HIGH TEMPS WILL GENERALLY BE NEAR NORMAL TODAY AND
MONDAY...THEN 1 TO 3 DEGS ABOVE NORMAL TUESDAY AND WEDNESDAY...THEN
5 TO 7 DEGS ABOVE NORMAL THURSDAY THROUGH SATURDAY. LOWS WILL RANGE
FROM 3 TO 6 DEGS ABOVE NORMAL...BUT THE WARMEST MORNINGS WILL LIKELY
OCCUR LATE NEXT WEEK AND WEEKEND.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE/DISCUSSION...MEYER
AVIATION/FIRE WEATHER...CERNIGLIA
PREVIOUS DISCUSSION...MOLLERE
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
945 AM MST SUN AUG 23 2015
.SYNOPSIS...
HIGH PRESSURE WILL BECOME REESTABLISHED TO OUR EAST...RESULTING IN
HIGHER THAN NORMAL RAIN CHANCES ACROSS THE LOWER DESERTS THROUGH
TUESDAY. DRIER CONDITIONS WILL RETURN BY MIDWEEK ALONG WITH ABOVE
NORMAL TEMPERATURES. WELL ABOVE NORMAL TEMPERATURES ARE POSSIBLE BY
NEXT WEEKEND.
&&
.DISCUSSION...
VERY COMPLEX FORECAST THROUGH THE NEXT 24 HOURS AS PATTERN
REALIGNMENT...SHIFTING AND VARIABLE STEERING FLOW...INSTABILITY
GRADIENTS...MOISTURE AVAILABILITY...AND INVERTED TROUGHING MAY BEGIN
TO COME TOGETHER TO ALLOW FOR ORGANIZED CONVECTION AND DEEPER
OUTFLOWS TO AFFECT THE FORECAST AREA.
1) WV IMAGERY AND OBJECTIVE ANALYSIS CLEARLY SHOW A STACKED ANTI-
CYCLONE NEAR THE NRN GULF OF CALIFORNIA THIS MORNING...WITH 12Z
REGIONAL SOUNDING SAMPLING VARIABLE TO PREDOMINANTLY NELY FLOW IN
THE H8-H5 LAYER. WITH THIS HIGH PRESSURE DOME REALIGNING TOWARDS THE
4-CORNERS...STEERING FLOW ALOFT SHOULD GENERALLY BACK TO AN E/SE
DIRECTION THIS EVENING...SUPPORTING WESTWARD MAINTENANCE OF ANY DEEP
OUTFLOWS GENERATED OVER ERN OR SERN ARIZONA.
2) 12Z KPSR AND KTWC SOUNDINGS ONCE AGAIN SHOWED GOOD 12 G/KG MIXING
RATIOS IN THE SFC-800MB LAYER...THOUGH DROPPING OFF ABOVE H7. MORE
BACKED FLOW IN THE H8-H5 LAYER SHOULD LESSEN THE EFFECTS OF DRY
MIXING INTO THE BOUNDARY LAYER THIS AFTERNOON...AND AN UPSTREAM SLUG
OF HIGHER MOISTURE (EVIDENCED BY ACCAS OVER ERN ARIZONA/WRN NEW
MEXICO) MAY INFUSE BETTER MOISTURE AROUND THE CRITICAL H7/MIXING
LAYER TOP LATER TODAY. HOWEVER...THIS CLOUD COVER AND CONVECTIVELY
CONTAMINATED ATMOSPHERE HAVE SIGNIFICANTLY REDUCED INSTABILITY OVER
ERN ARIZONA TODAY VERSUS THE PAST COUPLE DAYS.
3) A WEAK MIDLEVEL INVERTED TROUGH IS EVIDENT OVER NRN SONORA THIS
MORNING...WHICH COULD AID IN LARGE SCALE ASCENT LATER TODAY. SOME
MEASURE OF WLY JET STREAM FLOW IS NOTED IN OBJECTIVE
ANALYSIS...THOUGH SUBJECTIVELY IT APPEARS DIFLUENCE AT THIS LEVEL
MAY INCREASE THROUGH THE DAY IN SERN ARIZONA.
THE PREPONDERANCE OF HIGH RESOLUTION CONVECTIVE MODELS STILL SHOW
LIMITED CHANCES FOR PRECIPITATION BEYOND HIGHER ELEVATION LOCATIONS
OVER GILA/PINAL COUNTIES...BUT RATHER LONG REACHING OUTFLOW
BOUNDARIES MARCHING WEST THROUGH CNTRL (AND EVEN WRN) ARIZONA. BASED
ON SOUNDING AND MLCAPE ANALYSIS...COULD NOT SEE ANY JUSTIFICATION TO
INCREASE POPS...BUT RATHER MADE SOME SMALL DOWNWARD ADJUSTMENTS
AROUND THE PHOENIX METRO. STILL THINKING LARGEST IMPACT THIS EVENING
WOULD BE LOCALLY DENSE BLOWING DUST...WITH OUTFLOW BOUNDARIES
USHERING BETTER DEEP MOISTURE PROFILES SETTING THE STAGE FOR MORE
WIDESPREAD STORMS AND RAIN MONDAY AND TUESDAY. OTHERWISE IN THE
SHORT TERM...MADE SOME MINOR ADJUSTMENTS TO HOURLY TEMPERATURE AND
DEWPOINTS BASED ON OBSERVATIONAL TRENDS.
&&
.PREVIOUS DISCUSSION...
/455 AM MST SUN AUG 23 2015/
LATEST RAP STREAMLINE ANALYSIS SHOWS THE SUBTROPICAL RIDGE WEAKENING
ACROSS THE BAJA PENINSULA AND MIGRATING EASTWARD...RESULTING IN A
CESSATION OF THE PERSISTENT WESTERLY FLOW. A VERY WEAK STEERING FLOW
WILL DEVELOP TODAY FOLLOWED BY A REVERSAL IN THE WINDS TO LIGHT
EASTERLY BY TONIGHT. MEANWHILE...A VORT MAX ASSOCIATED WITH AN
INVERTED TROUGH IS EVIDENT NEAR THE BOOTHEEL OF NM. THIS SETUP IS
FAVORABLE FOR THUNDERSTORM ACTIVITY ACROSS EASTERN AND SOUTHEASTERN
AZ TODAY WITH PROPAGATION TO THE WEST INTO SOUTH-CENTRAL AZ THIS
EVENING.
CONVECTIVELY PARAMETERIZED MODELS SUCH AS THE GFS...ECMWF AND NMM-B
SUGGEST SOME POTENTIAL FOR THUNDERSTORMS ACROSS THE LOWER DESERTS
INCLUDING THE PHOENIX AREA. HOWEVER...CONSENSUS AMONG THE CONVECTIVE
ALLOWING WRFS IS THAT CONVERGING OUTFLOW BOUNDARIES WILL PRODUCE ONLY
ISOLATED CONVECTION ACROSS THE PHOENIX AREA...BUT WITH PERHAPS HIGHER
PROBABILITIES ACROSS THE SOUTHWEST DESERTS. MOST LIKELY IMPACT
TONIGHT IS BLOWING DUST...THOUGH THE POTENTIAL CERTAINLY EXISTS FOR
THUNDERSTORMS CONTAINING STRONG WINDS AND DOWNBURSTS...PARTICULARLY
ACROSS PORTIONS OF MARICOPA AND PINAL COUNTIES. WITH THE INVERTED
TROUGH DRAPED ACROSS THE LOWER DESERTS OVERNIGHT...CONVECTION ALSO
CANNOT BE RULED OUT THROUGH MONDAY MORNING.
BEST CHANCE FOR PRECIPITATION APPEARS TO BE MONDAY AS THE MONSOON
HIGH DRIFTS TOWARDS THE FOUR CORNERS RESULTING IN A MOIST
SOUTHEASTERLY FLOW. MODELS ALSO INDICATE THAT THE 250 MB HIGH
DISPLACED TO THE SOUTH WILL PRODUCE A DIFLUENT AND DIVERGENT
PATTERN IN THE UPPER LEVELS...HELPING TO PROVIDE ASCENT WHICH MAY
OFFSET ANY LACK OF INSTABILITY DUE TO THE WIDESPREAD CLOUDINESS.
THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL PERSIST TUESDAY BUT
WILL SHIFT SOMEWHAT TO THE WEST. LATEST MODELS SUGGEST THAT SEVERAL
TRAILING VORT MAXES AND MCVS WILL PROVIDE ASCENT IN A RELATIVELY
STRONG AND MOIST SOUTHERLY FLOW. THE FOCUS FOR PRECIPITATION WILL
SHIFT NORTHWARD WEDNESDAY AS THE AFOREMENTIONED TROUGH ACCELERATES
NORTHEASTWARD AROUND THE ANTICYCLONE IN NM.
GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE RIDGE WILL AGAIN MIGRATE TO
OUR SOUTH LATE IN THE WEEK...RESULTING IN A SOUTHWESTERLY FLOW AND A
RETURN TO WARMER AND DRIER CONDITIONS. ABOVE NORMAL TEMPERATURES ARE
LIKELY BEGINNING THURSDAY WITH HIGHS IN THE PHOENIX AREA POTENTIALLY
REACHING 110 DEGREES AGAIN BY NEXT SATURDAY...AND EVEN WARMER ACROSS
SOUTHEASTERN CA. THIS COULD BE THE WARMEST AUGUST ON RECORD FOR BOTH
PHOENIX AND YUMA AND THE PERIOD OF ABOVE NORMAL TEMPERATURES TO END
THE MONTH MAY HELP CLINCH THE TOP SPOT FOR BOTH LOCATIONS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
MOSTLY CLEAR SKIES AND TYPICAL AM EASTERLY WINDS TO PERSIST THRU
MIDDAY. WINDS TO GRADUALLY SWING AROUND TO W-SW PSBLY AN HOUR OR TWO
EARLIER THAN THEIR USUAL EARLY AFTN WINDOW...PSBLY AS EARLY AS
23/18Z. TODAY BEGINS A SEVERAL-DAY RETURN PERIOD OF MORE FAVORABLE
MONSOON STORM CHANCES ACROSS THE LOWER DESERTS AND SURVIVING INTO
CORNERS OF THE PHX METRO TO START. HI-RES MODEL GUIDANCE AND EARLY
AM CCFP INDICATE STORMS TO DEVELOP FIRST ALONG THE MOGOLLON RIM BY
MIDDAY AND AN HOUR OR TWO LATER ACROSS SE AZ.
INITIAL BEST GUESS AT TIMING THE FIRST...IN A POTENTIAL FEW...OUTFLOW
INTRUSION...COULD BE BETWEEN THE 24/00-02Z WINDOW FROM EAST-
NORTHEAST. ADDITIONAL OUTFLOW PUSH FROM THE SOUTH COULD EXPAND INTO
THE PHX METRO POST 02Z...ALONG WITH ISO. POP-UP SHOWER AND STORM
ACTIVITY WITH ITS PASSAGE. GNLY OPENED WITH VCSH AROUND 24/02-03Z
TIMEFRAME FOR THE TERMINALS. VSBY REDUCTION IS PSBL EITHER IN
SUSPENDED/LOFTED DUST OR A MORE CONSOLIDATED OUTFLOW AND THICKER
DUST...BUT HELD OFF FROM INCLUDING VSBY REDUCTION IN THE 12Z TAF
PACKAGE ATTM. DEPENDING ON WHERE THE OUTFLOW ORIGINATES WILL HAVE
BEARING ON WHAT AMOUNT...IF ANY...DUST IT MANAGES TO PICK UP.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY CLEAR SKIES AND PERSISTENT SOUTH TO SOUTHEASTERLY WINDS
FORECAST FOR THE WESTERN TERMINALS TODAY AND THIS EVENING. STORM
ACTIVITY SHOULD STAY WILL TO THE EAST ACROSS AZ THIS
AFTN/EVENING...WITH SOME PSBL HIGH LEVEL DEBRIS CLOUD IN LATER INTO
THE OVERNIGHT FOR KBLH.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
MONSOON MOISTURE LEVELS AND HUMIDITIES WILL PERSIST TUESDAY AND
WEDNESDAY AS A SERIES OF UPPER LEVEL DISTURBANCES MOVE IN FROM THE
SOUTHEAST. THESE DISTURBANCES WILL SUPPORT ELEVATED CHANCES FOR MORE
WIDESPREAD AND SUBSTANTIAL STORM DEVELOPMENT REGION-WIDE...WITH
STORM CHANCES REACHING BEYOND THE CO RIVER VALLEY. MIN RH VALUES
WILL GENERALLY RANGE BETWEEN 20 TO 30 PERCENT WITH GOOD OVERNIGHT
RECOVERY. OUTSIDE OF THUNDERSTORM OUTFLOW AND VICINITY WINDS...SFC
WINDS WILL BEGIN TO FOLLOW TYPICAL DIURNAL/DRAINAGE DRIVEN TRENDS. A
DRAW DOWN OF MONSOON MOISTURE IS STILL FORECAST TOWARDS THE END OF
THE WEEK...BUT MAY OCCUR AT A SLOWER RATE THAN ORIGINALLY THOUGHT.
THE UPPER RIDGE WILL GRADUALLY POSITION ITSELF TO DRAW IN DRIER
WESTERLY FLOW ALOFT...RELEGATING STORM CHANCES BACK ACROSS THE
EASTERN AZ AND THE HIGHER TERRAIN. AS THE AIRMASS SLOWLY DRIES
OUT...DAYTIME TEMPERATURES WILL RISE TO ABOVE NORMAL VALUES AND IN
SOME OF THE SOUTHEAST CA FIRE ZONES PUSH THE 110F MARK BY THE
WEEKEND.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MO/HIRSCH
AVIATION...NOLTE
FIRE WEATHER...NOLTE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
930 AM MST SUN AUG 23 2015
.SYNOPSIS...CONDITIONS ARE STILL FAVORABLE FOR AN INCREASE IN THE
STRENGTH AND COVERAGE OF STORMS LATER TODAY AND MONDAY...ALTHOUGH
SOME VALLEY DEVELOPMENT WILL BE DELAYED. SOME STORMS WILL GENERATE
STRONG WINDS AND HEAVY RAIN. THE INCREASED MOISTURE WILL ALSO KEEP
DAYTIME TEMPERATURES CLOSER TO SEASONAL AVERAGES. FOR THE SECOND
HALF OF THE NEW WEEK...BUILDING HIGH PRESSURE WILL TEND TO SUPPRESS
THUNDERSTORM COVERAGE WHILE BRINGING HOTTER TEMPERATURES TO THE AREA.
&&
.DISCUSSION...THE 12Z KTWC SOUNDING IS A BIT WORKED OVER AS
EXPECTED. CURRENT THINKING IS THAT IT WILL RECOVER ENOUGH FOR STRONG
EASTERLY/NORTHEASTERLY OUTFLOW TO FIRE CONVECTION ACROSS METRO
TUCSON AGAIN LATE IN THE AFTERNOON OR EARLY EVENING. WE WILL SEE HOW
THE ATMOSPHERE IS PROGRESSING WITH AN 18Z RELEASE IN A LITTLE WHILE.
LATEST HRRR CONTINUES TO BACK-PEDAL ON STORM CHANCES TODAY WHILE THE
12Z STANDARD GFS/NAM RUNS WERE MORE FAVORABLE SUSTAINING DEEP
OUTFLOW FROM THE EAST INTO LOWER DESERT LOCATIONS DURING LATE
AFTERNOON AND EVENING HOURS. THIS REMAINS OUR CURRENT FORECAST
SCENARIO PENDING THE PROGRESS REPORT FROM THE 18Z SOUNDING.
WE`RE ALSO LOOKING AT THE ORIENTATION OF THE EXPECTED OUTFLOWS FROM
CONVECTION IN EASTERN AREAS FOR POSSIBLE LARGE SCALE BLOWING DUST
CONCERNS...ESPECIALLY IN PINAL COUNTY.
PLEASE SEE THE PREVIOUS DISCUSSION FOR ADDITIONAL DETAILS.
&&
.AVIATION...VALID THRU 24/18Z.
MAINLY W OF KTUS...FEW-SCTD 8-12KFT OTRW CLR. FROM KTUS S AND E...
SCTD TO LCLY BKN CLOUDS AT 8-12K FT. AFT 23/19Z ISOLD TO SCTD
-SHRA/TS. AFT 24/00Z SCT-BKN 8-10K FT AREA WIDE WITH BKN LYRS ABV
AND SCT SHRA/TSRA. BRIEF MVFR CONDS...ALONG WITH STRONG GUSTY WINDS
POSSIBLE IN AN AROUND SHRA/TSRA. WINDS AWAY FROM STORMS GENERALLY
LIGHT AND TERRAIN DRIVEN. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...GOOD THUNDERSTORM CHANCES LATER TODAY WELL INTO
TONIGHT THEN AGAIN MONDAY AS A DISTURBANCE MOVES NW ACROSS THE
REGION. DECENT STORM CHANCES REMAIN TUESDAY INTO WEDNESDAY DUE TO
PLENTY OF MOISTURE LINGERING OVER THE REGION. AN UPPER RIDGE WILL
BUILD OVER THE AREA LATE IN THE WEEK INTO NEXT WEEKEND RESULTING IN
A SIGNIFICANT DECREASE IN SHOWER AND THUNDERSTORMS AND TEMPERATURES
RISING TO NEAR RECORD LEVELS FRIDAY ONWARD. OUTSIDE OF THUNDERSTORM
WINDS...WINDS WILL BE TYPICAL FOR MID AUGUST AND GENERALLY LESS THAN
15 MPH WITH AFTERNOON GUSTINESS. CERNIGLIA
&&
.DISCUSSION...WATER VAPOR IMAGERY...23/00Z UPPER-AIR PLOTS AND
LATEST MODEL DATA INDICATE THAT HIGH PRESSURE EXTENDS GENERALLY FROM
SRN CALIFORNIA/NRN BAJA ACROSS THE DESERT SOUTHWEST AND INTO NEW
MEXICO. TROUBLE WITH UPPER-AIR BALLOON LAUNCHES YESTERDAY AFTERNOON
RESULTED IN NO FLIGHT FOR KTWC AND A SHORT FLIGHT FROM KPSR (ONLY UP
TO AROUND 620MB)...SO NO PW INFO FROM THAT SOURCE. HOWEVER...THE U
OF A GPS PW VALUES SHOW AROUND 1.2 INCHES FOR TUS AND SIMILAR VALUES
FROM THE SATELLITE DERIVED BLENDED TOTAL PW IMAGERY. IR SATELLITE
IMAGERY SHOWS LINGERING CONVECTION WELL TO OUR EAST OVER SOUTH
CENTRAL NEW MEXICO...WITH MID TO HIGH LEVEL DEBRIS CLOUDS EXTENDING
WESTWARD INTO SOUTHEAST ARIZONA AS FAR AS THE TUCSON AREA. THESE
CLOUDS SHOW SIGNS OF ERODING.
MODELS INDICATE THAT THE HIGH SHIFTS TO A POSITION THAT EXTENDS FROM
ARIZONA THROUGH NEW MEXICO AND INTO EASTERN TEXAS TODAY. AS THIS
OCCURS FLOW WILL BECOME EAST TO SOUTHEAST WITH A WEAK DISTURBANCE
PROGGED TO MOVE ACROSS NORTHERN CHIHUAHUA MEXICO AND ACROSS THE
ARIZONA/SONORAN BORDER THIS AFTERNOON THROUGH LATE MONDAY AS IT
MOVES TOWARD THE LOWER COLORADO RIVER BASIN. MODELS ARE ADVERTISING
THE PW`S TO INCREASE TO AROUND 1.4-1.6 INCHES TODAY FOR TUCSON WITH
LESSER VALUES EAST. BY MONDAY VALUES EXPECTED TO RANGE FROM 1.2-1.4
INCHES EAST...1.5-1.6 INCHES CENTRAL AREAS AND 1.8-2.0 INCHES FOR
THE FAR WEST (AJO/ORGAN PIPE). WITH THE COMBO OF AMPLE MOISTURE AND
THE AFOREMENTIONED TRIGGERING MECHANISM OF THE WEAK VORT MAX
TRAVERSING SOUTHERN ARIZONA...EXPECT SCATTERED TO LOCALLY NUMEROUS
SHOWERS AND THUNDERSTORMS TODAY THROUGH MONDAY...WITH THE BEST
THREAT OCCURRING LATE THIS AFTERNOON AND THIS EVENING...BUT STILL A
DECENT THREAT AGAIN MONDAY AFTERNOON/EVENING.
BY TUESDAY RAIN CHANCES IN THE LOW END SCATTERED CATEGORY NEARLY
AREA WIDE AS THE WEAK DISTURBANCE MOVES UP THE COLORADO RIVER VALLEY
AS THE HIGH SHIFTS TO A POSITION OVER EASTERN COLORADO. SO...
WITHOUT THAT ENHANCEMENT STILL STORMS AROUND...BUT NOT AS NUMEROUS
AS WHAT IS EXPECTED FOR TODAY AND MONDAY.
BY WEDNESDAY THE HIGH IS EXPECTED TO MOVE TO NEW MEXICO/WEST TEXAS
WITH PW`S EXPECTED TO BE DOWN FROM PREVIOUS DAYS...GENERALLY IN THE
1.1 TO 1.4 INCH RANGE FOR EAST AND CENTRAL LOCATIONS.
FOR THURSDAY AND CONTINUING THROUGH SATURDAY...THE HIGH IS EXPECTED
TO SHIFT TO A POSITION NEARLY OVERHEAD OR JUST TO OUR SOUTH...GIVING
US A DRIER SOUTHWESTERLY FLOW ALOFT...WITH PW`S DROPPING TO AROUND
THE 1 INCH MARK BY SATURDAY. THAT SAID...I TWEAKED THE POP FORECAST
FOR LATE IN THE PERIOD TO GIVE US MAINLY ISOLATED TO LOW END
SCATTERED ACTIVITY MAINLY NEAR THE NEW MEXICO BORDER FOR FRIDAY AND
SATURDAY.
FOR TUCSON...HIGH TEMPS WILL GENERALLY BE NEAR NORMAL TODAY AND
MONDAY...THEN 1 TO 3 DEGS ABOVE NORMAL TUESDAY AND WEDNESDAY...THEN
5 TO 7 DEGS ABOVE NORMAL THURSDAY THROUGH SATURDAY. LOWS WILL RANGE
FROM 3 TO 6 DEGS ABOVE NORMAL...BUT THE WARMEST MORNINGS WILL LIKELY
OCCUR LATE NEXT WEEK AND WEEKEND.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
DISCUSSION...MEYER
AVIATION/FIRE WEATHER...CERNIGLIA
PREVIOUS DISCUSSION...MOLLERE
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1149 AM MDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 1149 AM MDT SUN AUG 23 2015
UPDATED TO EXTENT COVERAGE OF SHRA/TSRA ACROSS BACA COUNTY.
UPDATE ISSUED AT 945 AM MDT SUN AUG 23 2015
UPDATED TO ADD AREAS OF SMOKE AND HAZE FOR TODAY TO AREAS ALONG
THE LOWER EASTERN SLOPES...WEST OF THE I-25 CORRIDOR...WITH LOW
LEVEL UPSLOPE FLOW AND MID LEVEL INVERSIONS LIKELY KEEPING PAC
NORTHWEST SMOKE...BROUGHT IN BY LAST NIGHTS COLD FRONT...IN PLACE.
UPDATE ISSUED AT 743 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER AND POPS TO REFLECT CURRENT
SATELLITE AND RADAR. LOADED LATEST OBSERVATIONS INTO FRONT END OF
FORECAST GRIDS.
UPDATE ISSUED AT 647 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER PER SATELLITE AND LOADED LATEST
OBSERVATIONS INTO FRONT END OF FORECAST GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM MDT SUN AUG 23 2015
...THUNDERSTORMS MAINLY MOUNTAINS TODAY...
COLD FRONT HAS PUSHED A MASS OF RELATIVELY COOL STABLE AIR SOUTH
ACROSS THE PLAINS...WITH WIDESPREAD MID LEVEL CLOUDS ACROSS THE
EASTERN MOUNTAINS AND PLAINS BUT NO PRECIPITATION. THE MOUNTAINS
AND HIGH VALLEYS TO THE WEST REMAIN CLEAR TO PARTLY CLOUDY...WITH
SOME MOSTLY CLOUDY SKIES OVER THE EASTERN SAN JUANS.
FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW THE ONLY REAL PROSPECTS
FOR THUNDERSTORMS TO BE OVER THE MOUNTAINS AND HIGH VALLEYS. THE
PLAINS SOUNDINGS SHOW A STRONG CAP. OF NOTE...HOWEVER...ARE RUNS OF
THE EXPERIMENTAL HRRR AND...TO A LESSER EXTENT...THE 4KM NSSL
WRF...THAT SHOW SOME CONVECTION MOVING OFF THE MOUNTAINS AND ACROSS
THE I-25 CORRIDOR...MAINLY BETWEEN 4 PM AND 8 PM. NOT SURE IF THIS
WILL HAPPEN GIVEN THE STRONG CAP INDICATED IN THE FORECAST SOUNDINGS
BUT SOMETHING TO KEEP AN EYE ON. PROBABLY WHAT THESE MODELS ARE
DOING IS DEVELOPING ELEVATED CONVECTION...AND TRACKING IT SOUTHEAST
ACROSS THE PLAINS...ABOVE THE STABLE AIR. USUALLY WHEN THIS
HAPPENS...HOWEVER...ANY ELEVATED CONVECTION DIES OUT ONCE IT MOVES
OVER THE STABLE AIR. SO...SUSPECT THIS IS WHAT WILL HAPPEN.
PRIMARY THREATS FROM STORMS OVER THE MOUNTAINS AND HIGH VALLEYS
TODAY WILL BE LIGHTNING AND WIND GUSTS TO AROUND 40 MPH. THERE
COULD ALSO BE SOME SPOTTY HEAVY RAIN OUT THERE.
TEMPERATURES BEHIND THE COLD FRONT WILL BE ABOUT 15-20 DEGREES
COOLER OVER THE EAST TODAY WITH COMFORTABLE HIGHS RANGING FROM THE
MID 70S TO MID 80S. FOR THE MOUNTAINS AND HIGH VALLEYS...NOT QUITE
AS MUCH COOLING...RANGING FROM JUST A COUPLE DEGREES COOLER IN SOME
AREAS UP TO ABOUT 10 DEGREES COOLER IN OTHERS. HIGH VALLEY
TEMPERATURES SHOULD RANGE FORM THE 70S TO LOWER 80S WITH MOUNTAIN
READINGS MOSTLY IN THE 60S AND 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 534 AM MDT SUN AUG 23 2015
.MONDAY AND TUESDAY...UPPER RIDGE REMAINS OVERHEAD WITH A MODEST
AMOUNT OF MID LEVEL MOISTURE OVER THE REGION. BEST CHANCES FOR
DIURNAL CONVECTION WILL BE OVER AND NEAR THE MOUNTAINS. WITH WEAK
WINDS ALOFT...ANTICIPATE CONVECTION WILL HAVE DIFFICULTY MOVING
OFF OF THE HIGHER TERRAIN. NAM CONTINUES TO SHOW SOME INCREASED
CAPE NEAR THE KANSAS BORDER DURING THE AFTERNOON AND EVENING.
GIVEN THE LACK OF A SHORTWAVE...MAINTAINED SILENT POPS OVER THE
PLAINS. WARM WEATHER CONTINUES WITH HIGHS ABOVE AVERAGE ON BOTH
DAYS.
.WEDNESDAY AND THURSDAY...AN UPPER TROUGH WILL APPROACH THE WEST
COAST INCREASING THE INFLUX OF MONSOON MOISTURE INTO THE REGION.
LATEST SIMULATIONS HAVE WEDNESDAY BEING THE WETTEST DAY OVER AND
NEAR THE MOUNTAINS WITH GREATEST AMOUNT OF MOISTURE. GFS AND EC
DEVELOP A TROUGH OVER THE REGION WHICH SLOWLY MOVES EAST ON
THURSDAY. WITH THE TROUGH NEAR THE KANSAS BORDER BY THURSDAY
AFTERNOON...CHANCES FOR CONVECTION WILL INCREASE NEAR THE KANSAS
BORDER. HAVE CONCERNS THAT THE CONVECTIVE PARAMETERIZATION COULD
BE INFLUENCING THE DEVELOPMENT OF THIS TROUGH...WHICH COULD AFFECT
THE LOCATION...TIMING AND STRENGTH OF CONVECTION.
.FRIDAY AND SATURDAY...MODELS HAVE DIFFERENCES IN THE SPEED OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. GENERAL TREND
WILL BE TO TURN FLOW ALOFT MORE SOUTHWESTERLY BRINGING DRIER AIR
ALOFT INTO THE REGION. GRIDS GENERALLY HAVE ISOLATED TO SCATTERED
CONVECTION MOSTLY CONFINED TO THE MOUNTAINS WITH TEMPERATURE NEAR
OR ABOVE NORMAL. --PGW--
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1132 AM MDT SUN AUG 23 2015
MAINLY VFR CONDITIONS EXPECTED AT COS...PUB AND ALS OVER THE NEXT
24 HOURS...ALTHOUGH THERE COULD SOME AREAS OF REDUCED VISIBILITIES ALONG
AND WEST OF THE I-25 CORRIDOR THROUGH THE AFTERNOON AND EVENING...WITH
BREEZY SOUTH TO SOUTHEAST WINDS AND MID LEVEL INVERSIONS KEEPING SMOKE
FROM PAC NW WILDFIRES IN PLACE ALONG THE FRONT RANGE.
ISOLATED TO SCATTERED AFTERNOON AND EARLY EVENING STORMS EXPECTED
OVER AND NEAR THE HIGHER TERRAIN...WITH BEST CHANCES OF STORMS AFFECTING
TERMAINALS AT ALS. A FEW STORMS COULD TRY A MOVE EAST ONTO THE I-25
CORRIDOR...THOUGH ATMOSPHERE BEHIND LAST NIGHTS COLD FRONT LOOKS
BE TOO STABLE TO SUSTAIN STORMS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...LW
LONG TERM...PGW
AVIATION...MW
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1133 AM MDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 945 AM MDT SUN AUG 23 2015
UPDATED TO ADD AREAS OF SMOKE AND HAZE FOR TODAY TO AREAS ALONG
THE LOWER EASTERN SLOPES...WEST OF THE I-25 CORRIDOR...WITH LOW
LEVEL UPSLOPE FLOW AND MID LEVEL INVERSIONS LIKELY KEEPING PAC
NORTHWEST SMOKE...BROUGHT IN BY LAST NIGHTS COLD FRONT...IN PLACE.
UPDATE ISSUED AT 743 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER AND POPS TO REFLECT CURRENT
SATELLITE AND RADAR. LOADED LATEST OBSERVATIONS INTO FRONT END OF
FORECAST GRIDS.
UPDATE ISSUED AT 647 AM MDT SUN AUG 23 2015
ADJUSTED SHORT TERM SKY COVER PER SATELLITE AND LOADED LATEST
OBSERVATIONS INTO FRONT END OF FORECAST GRIDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 534 AM MDT SUN AUG 23 2015
...THUNDERSTORMS MAINLY MOUNTAINS TODAY...
COLD FRONT HAS PUSHED A MASS OF RELATIVELY COOL STABLE AIR SOUTH
ACROSS THE PLAINS...WITH WIDESPREAD MID LEVEL CLOUDS ACROSS THE
EASTERN MOUNTAINS AND PLAINS BUT NO PRECIPITATION. THE MOUNTAINS
AND HIGH VALLEYS TO THE WEST REMAIN CLEAR TO PARTLY CLOUDY...WITH
SOME MOSTLY CLOUDY SKIES OVER THE EASTERN SAN JUANS.
FORECAST SOUNDINGS FOR THIS AFTERNOON SHOW THE ONLY REAL PROSPECTS
FOR THUNDERSTORMS TO BE OVER THE MOUNTAINS AND HIGH VALLEYS. THE
PLAINS SOUNDINGS SHOW A STRONG CAP. OF NOTE...HOWEVER...ARE RUNS OF
THE EXPERIMENTAL HRRR AND...TO A LESSER EXTENT...THE 4KM NSSL
WRF...THAT SHOW SOME CONVECTION MOVING OFF THE MOUNTAINS AND ACROSS
THE I-25 CORRIDOR...MAINLY BETWEEN 4 PM AND 8 PM. NOT SURE IF THIS
WILL HAPPEN GIVEN THE STRONG CAP INDICATED IN THE FORECAST SOUNDINGS
BUT SOMETHING TO KEEP AN EYE ON. PROBABLY WHAT THESE MODELS ARE
DOING IS DEVELOPING ELEVATED CONVECTION...AND TRACKING IT SOUTHEAST
ACROSS THE PLAINS...ABOVE THE STABLE AIR. USUALLY WHEN THIS
HAPPENS...HOWEVER...ANY ELEVATED CONVECTION DIES OUT ONCE IT MOVES
OVER THE STABLE AIR. SO...SUSPECT THIS IS WHAT WILL HAPPEN.
PRIMARY THREATS FROM STORMS OVER THE MOUNTAINS AND HIGH VALLEYS
TODAY WILL BE LIGHTNING AND WIND GUSTS TO AROUND 40 MPH. THERE
COULD ALSO BE SOME SPOTTY HEAVY RAIN OUT THERE.
TEMPERATURES BEHIND THE COLD FRONT WILL BE ABOUT 15-20 DEGREES
COOLER OVER THE EAST TODAY WITH COMFORTABLE HIGHS RANGING FROM THE
MID 70S TO MID 80S. FOR THE MOUNTAINS AND HIGH VALLEYS...NOT QUITE
AS MUCH COOLING...RANGING FROM JUST A COUPLE DEGREES COOLER IN SOME
AREAS UP TO ABOUT 10 DEGREES COOLER IN OTHERS. HIGH VALLEY
TEMPERATURES SHOULD RANGE FORM THE 70S TO LOWER 80S WITH MOUNTAIN
READINGS MOSTLY IN THE 60S AND 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 534 AM MDT SUN AUG 23 2015
.MONDAY AND TUESDAY...UPPER RIDGE REMAINS OVERHEAD WITH A MODEST
AMOUNT OF MID LEVEL MOISTURE OVER THE REGION. BEST CHANCES FOR
DIURNAL CONVECTION WILL BE OVER AND NEAR THE MOUNTAINS. WITH WEAK
WINDS ALOFT...ANTICIPATE CONVECTION WILL HAVE DIFFICULTY MOVING
OFF OF THE HIGHER TERRAIN. NAM CONTINUES TO SHOW SOME INCREASED
CAPE NEAR THE KANSAS BORDER DURING THE AFTERNOON AND EVENING.
GIVEN THE LACK OF A SHORTWAVE...MAINTAINED SILENT POPS OVER THE
PLAINS. WARM WEATHER CONTINUES WITH HIGHS ABOVE AVERAGE ON BOTH
DAYS.
.WEDNESDAY AND THURSDAY...AN UPPER TROUGH WILL APPROACH THE WEST
COAST INCREASING THE INFLUX OF MONSOON MOISTURE INTO THE REGION.
LATEST SIMULATIONS HAVE WEDNESDAY BEING THE WETTEST DAY OVER AND
NEAR THE MOUNTAINS WITH GREATEST AMOUNT OF MOISTURE. GFS AND EC
DEVELOP A TROUGH OVER THE REGION WHICH SLOWLY MOVES EAST ON
THURSDAY. WITH THE TROUGH NEAR THE KANSAS BORDER BY THURSDAY
AFTERNOON...CHANCES FOR CONVECTION WILL INCREASE NEAR THE KANSAS
BORDER. HAVE CONCERNS THAT THE CONVECTIVE PARAMETERIZATION COULD
BE INFLUENCING THE DEVELOPMENT OF THIS TROUGH...WHICH COULD AFFECT
THE LOCATION...TIMING AND STRENGTH OF CONVECTION.
.FRIDAY AND SATURDAY...MODELS HAVE DIFFERENCES IN THE SPEED OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. GENERAL TREND
WILL BE TO TURN FLOW ALOFT MORE SOUTHWESTERLY BRINGING DRIER AIR
ALOFT INTO THE REGION. GRIDS GENERALLY HAVE ISOLATED TO SCATTERED
CONVECTION MOSTLY CONFINED TO THE MOUNTAINS WITH TEMPERATURE NEAR
OR ABOVE NORMAL. --PGW--
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1132 AM MDT SUN AUG 23 2015
MAINLY VFR CONDITIONS EXPECTED AT COS...PUB AND ALS OVER THE NEXT
24 HOURS...ALTHOUGH THERE COULD SOME AREAS OF REDUCED VISIBILITIES ALONG
AND WEST OF THE I-25 CORRIDOR THROUGH THE AFTERNOON AND EVENING...WITH
BREEZY SOUTH TO SOUTHEAST WINDS AND MID LEVEL INVERSIONS KEEPING SMOKE
FROM PAC NW WILDFIRES IN PLACE ALONG THE FRONT RANGE.
ISOLATED TO SCATTERED AFTERNOON AND EARLY EVENING STORMS EXPECTED
OVER AND NEAR THE HIGHER TERRAIN...WITH BEST CHANCES OF STORMS AFFECTING
TERMAINALS AT ALS. A FEW STORMS COULD TRY A MOVE EAST ONTO THE I-25
CORRIDOR...THOUGH ATMOSPHERE BEHIND LAST NIGHTS COLD FRONT LOOKS
BE TOO STABLE TO SUSTAIN STORMS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...LW
LONG TERM...PGW
AVIATION...MW
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
112 PM EDT SUN AUG 23 2015
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 344 AM EDT SUN AUG 23 2015
SCATTERED THUNDERSTORMS WILL ACCOMPANY A STRONG COLD
FRONT LATER TODAY. THE FRONT WILL SHIFT EAST QUICKLY THIS
EVENING...WITH HIGH PRESSURE REESTABLISHING OVER THE OHIO VALLEY.
DRY AND PLEASANT WEATHER IS EXPECTED FOR THE ENTIRE WEEK AS THE HIGH
REMAINS THE DOMINANT WEATHER FEATURE.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 936 AM EDT SUN AUG 23 2015
FOCUS FOR TODAY IS THE APPROACH OF A COLD FRONT FROM THE WEST
LATER THIS AFTERNOON. SCATTERED CONVECTION WILL REFIRE ALONG THE
FRONT AS IT MOVES THROUGH THE FORECAST AREA DURING THE AFTERNOON.
THIN AXIS OF DEEPER MOISTURE WITH PRECIP WATER VALUES AROUND 1.50
INCHES WILL ADVECT INTO THE REGION IMMEDIATELY AHEAD OF THE
BOUNDARY. THE DEEPER MOISTURE WILL COMBINE WITH PEAK MLCAPE VALUES
AT 1000-1500 J/KG...LOW LEVEL CONVERGENCE AND BL SHEAR VALUES
BRIEFLY PEAKING NEAR 30KTS AS THE PRIMARY CATALYSTS IN CONVECTIVE
DEVELOPMENT DURING THE AFTERNOON.
THERE ARE MITIGATING FACTORS IN PLAY THOUGH HOWEVER. DESPITE
DIFFLUENCE ALOFT...STRONGER UPPER FORCING WILL REMAIN DISPLACED TO
THE NORTH OF THE AREA IN CLOSER PROXIMITY TO THE UPPER LOW. MODEL
SOUNDINGS FROM BOTH THE OP GFS AND THE RAP HINT AT A WEAK CAPPING
INVERSION PRESENT NEAR 10KFT WITH LARGELY POOR LAPSE RATES WHICH
WOULD LIMIT AVAILABLE INSTABILITY AND CONVECTIVE COVERAGE. NAM MODEL
SOUNDINGS PRESENT LITTLE IN THE WAY OF CAPPING AND CONSEQUENTLY
GREATER AVAILABLE INSTABILITY DURING THE AFTERNOON...BUT THIS
SOLUTION IS NOT PREFERRED AS CLOSER ANALYSIS INDICATES THAT IT IS
LIKELY OVERDOING BOTH SURFACE TEMPS AND DEWPOINTS LATER TODAY.
TAKING ALL OF THIS INTO ACCOUNT...HAVE TRENDED TOWARDS A CONSENSUS
SOLUTION LED BY THE HI RES SUITE OF THE HRRR...RAP AND WRF WHICH
BRING A NARROW YET BROKEN CONVECTIVE LINE QUICKLY ACROSS THE
FORECAST AREA PRIMARILY BETWEEN 18Z AND 00Z. HIGHEST POPS WILL BE
EMPLOYED OVER THE NORTHEAST HALF OF THE FORECAST AREA WHERE
INSTABILITY WILL BE GREATEST AND INTERACT WITH BEST SHEAR AND
MOISTURE. STORMS ARE LIKELY TO DISRUPT OUTDOOR ACTIVITIES
BRIEFLY...WITH GUSTY WINDS AND LIGHTNING...AND POSSIBLY HAIL.
STRONGER CELLS WILL HAVE THE POTENTIAL FOR AN ISOLATED SEVERE RISK
WITH DAMAGING WINDS AND LARGE HAIL...ESPECIALLY NORTH AND EAST OF
THE INDY METRO. STORMS WILL END RAPIDLY WITH THE FRONTAL PASSAGE BY
EARLY EVENING.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE FOR HIGHS CONSIDERING
INCREASING CLOUDS AND STORMS FOR THE AFTERNOON. EXPECTING GENERALLY
LOW TO MID 80S.
&&
.SHORT TERM /|TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 344 AM EDT SUN AUG 23 2015
FORECAST CHALLENGES ARE MINOR THROUGH THE SHORT TERM...AS STRONG
HIGH PRESSURE BUILDS IN WITH DRY...PLEASANT WEATHER THROUGH MIDWEEK.
HELD ONTO A LOW CHANCE POPS OVER FAR EASTERN COUNTIES FOR A FEW
HOURS THIS EVENING TO ACCOUNT FOR ANY LINGERING CONVECTION AS THE
COLD FRONT SWEEPS OFF TO THE EAST. EXPECT THE ENTIRE FORECAST AREA
WILL BE DRY BY 02-03Z AT THE LATEST.
STRONG UPPER LOW BY LATE AUGUST STANDARDS WILL PINWHEEL SLOWLY
THROUGH THE GREAT LAKES...MAINTAINING A BROAD TROUGH WITH COOL
CYCLONIC FLOW OVER THE REGION THROUGH MIDWEEK. EXPECT PLENTY OF
SUNSHINE BOTH MONDAY AND TUESDAY WITH DIURNAL AFTERNOON CU IN THE
COLD ADVECTION REGIME. CU WILL DISSIPATE NEAR SUNSET BOTH
DAYS...SETTING THE STAGE FOR MAINLY CLEAR SKIES AT NIGHT WITH COOL
TEMPERATURES. ALL IN ALL...A VERY PLEASANT STRETCH OF WEATHER
UPCOMING FOR MUCH OF THIS WEEK.
TEMPS...UTILIZED A MOS BLEND FOR HIGHS MONDAY...THEN TRENDED TOWARDS
WARMER MAVMOS GUIDANCE FOR TUESDAY. HIGHS WILL RUN ABOUT 5-10
DEGREES BELOW NORMAL BOTH DAYS IN THE 70S. SHOULD SEE A NICE RURAL-
URBAN SPLIT IN OVERNIGHT TEMPS WITH POTENTIAL FOR NORMAL COOL SPOTS
ACROSS THE FORECAST AREA TO FALL INTO THE 40S...ESPECIALLY
EARLY TUESDAY MORNING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 223 AM EDT SUN AUG 23 2015
GUIDANCE CONTINUES TO DEPICT A DRY AND COOL EXTENDED PORTION OF THE
FORECAST...ALTHOUGH WITH SOME MODERATION OF TEMPERATURES BACK TOWARD
NORMAL NEAR THE END OF THE PERIOD.
MODELS NOW SHOW A STRONGER SURFACE RIDGE ACROSS THE AREA LATE IN THE
WEEK...WHICH WOULD PREVENT FRONTAL ZONE FROM MAKING IT INTO THE AREA
UNTIL AFTER THE SEVEN DAY FORECAST PERIOD. CAN GO WITH A DRY
FORECAST THROUGHOUT THE EXTENDED.
BLENDED INITIALIZATION HANDLED THIS WELL AND ONLY MINOR TWEAKS WERE
REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 23/1800Z TAF ISSUANCE/...
ISSUED AT 112 PM EDT SUN AUG 23 2015
MVFR CEILING AT TIMES WITH SCATTERED SHOWERS OR THUNDERSTORMS THIS AFTERNOON.
OTHERWISE...VFR FROM THIS EVENING ON.
A COLD FRONT NEAR A CHICAGO TO SAINT LOUIS LINE WILL PUSH ACROSS OUR REGION LATER
THIS AFTERNOON. SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL OCCUR ALONG AND
AHEAD OF THIS FRONT. MOST PLACES WHEN VCTS OR VCSH AS ANY SHOWERS OR THUNDERSTORMS
WILL BE BRIEF. WEATHER DEPICTION SHOWS SOME AREAS OF MVFR CEILINGS...BUT THIS
SHOULD RISE TO NEAR OR ABOVE 3 THOUSAND FEET BY LATE AFTERNOON. CLEARING WILL
OCCUR BEHIND COLD FRONT AND FROM MID TO LATE EVENING ON EXPECT VFR WITH MOSTLY
CLEAR SKIES AS DRIER AIR SPREADS INTO OUR REGION.
WINDS WILL BE FROM THE SOUTHWEST AHEAD OF THE FRONT UP TO 10 KNOTS AND GUSTS
TO 18 KNOTS. LIGHT WEST OR NORTHWEST WINDS WILL BE THE RULE TONIGHT. WINDS
MAY PICK UP A LITTLE BY MIDDAY MONDAY WITH SOME DAYTIME MIXING...BUT WIND
SPEEDS WILL BE LESS THAN 15 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM...NIELD
AVIATION...JH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1110 AM MDT SUN AUG 23 2015
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 406 AM MDT SUN AUG 23 2015
FORECAST CONCERNS WILL BE TEMPERATURES...AND LOW CHANCE FOR
PRECIPITATION AT THE END OF THIS PERIOD. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO NORTH AMERICA.
AT JET LEVEL..MODELS STARTED OUT FINE. AT MID LEVELS...THE MODELS
WERE CLOSE WITH THE GFS/CANADIAN DOING A LITTLE BETTER THAN THE
UKMET...NAM AND ECMWF. THE SREF WAS DOING A LITTLE BETTER THAN THE
ECMWF ON THE SURFACE WIND AND PRESSURE PATTERN. THE ECMWF WAS
DOING A LITTLE BETTER THAN THE CANADIAN...NAM AND GFS ON THE LOW
LEVEL THERMAL FIELD.
DESPITE CLOSE SOLUTIONS ALOFT FROM MONDAY INTO TUESDAY NIGHT...
MODELS HANDLE THE SURFACE PATTERN DIFFERENTLY WHICH DEPENDING ON
WHICH SOLUTION IS CORRECT COULD HAVE MAJOR AFFECTS ON THE FORECAST.
SO FORECAST CONFIDENCE IS BELOW AVERAGE DURING THIS TIME PERIOD.
TODAY/TONIGHT...INITIAL PROBLEM WILL BE TO SEE IF ANY NOCTURNAL
CONVECTION WILL BE AROUND IN THE MORNING. 00Z NAM WAS CATCHING THE
ISOLATED PRECIPITATION OVER THE WEST CENTRAL PORTION OF THE AREA
DURING THE MID AND LATE EVENING WITH A LITTLE LEFT OVER THE FAR
SOUTHERN PORTION AT 12Z. THE LATEST RAP WAS SHOWING THE SAME THING.
WILL CONTINUE TO WATCH TRENDS BUT IT DOES LOOK LIKE ALL THUNDERSTORMS
WILL BE SOUTH OF THE AREA AT THE BEGINNING OF THE DAY.
IT LOOKS LIKE WARM AIR ADVECTION ALOFT HAS SPREAD A THICKER MID DECK
OF CLOUD COVER OVER THE AREA. IT DOES LOOK LIKE THESE CLOUDS WILL
THEN OUT BY LATE MORNING. IF THEY CHOOSE TO HANG ON LONGER THEN
THE MAXES MAY BE IMPACTED. LIGHT AND VARIABLE TO LIGHT UPSLOPE
WINDS WILL TRANSITION TO A SOUTHERLY FLOW MAINLY OVER THE WESTERN
PORTION BY LATE IN THE AFTERNOON. MUCH COOLER AIR MASS AND
UNFAVORABLE WIND FIELD WILL MAKE FOR A COOL DAY WITH GUIDANCE IN
CLOSE AGREEMENT. LIGHT SOUTHERLY WINDS TONIGHT. AGAIN GUIDANCE
PRETTY CLOSE AND TENDED TO GO TOWARD THE COOLER GUIDANCE.
MONDAY/MONDAY NIGHT... MODELS DISAGREE ON HOW MUCH TO WARM UP THE
MAXES. SURFACE RIDGE WILL BE MOVING TO THE EAST WITH THE LEE TROUGH
DEVELOPING TO THE WEST. THERE SHOULD BE NO DOWNSLOPE COMPONENT TO
THE WINDS AND BELIEVE AT THIS TIME THAT THE WARMER GFS/MAV AND
CANADIAN ARE TOO WARM. TENDED TO GO IN THE MIDDLE OF THE TWO
EXTREMES.
THIS IS WHERE THE FORECAST STARTS GETTING MORE INTERESTING AND
UNCERTAIN. MODELS DISAGREE ON EXACTLY WHERE BUT THEY ALL INDICATE A
WEAK JET PROVIDING SOME LIFT ACROSS THE AREA FROM THE LATE EVENING
INTO THE OVERNIGHT HOURS. MODELS SHOW A SHORTWAVE TROUGH MOVING
ACROSS THE AREA AT THAT TIME WITH A DECENT BAROCLINIC ZONE ACROSS
THE EASTERN ZONES. MOISTURE DEFINITELY APPEARS TO BE A PROBLEM BUT
THERE LOOKS TO BE A LOT OF ELEVATED CAPE WITH THE ELEVATED CINH
POSSIBLY BEING OVERCOME. ONLY MODELS SHOWING SOME QPF ARE THE GFS
AND THE ENSEMBLE MEAN. AT THIS TIME WILL PUT IN A SLIGHT CHANCE OF
THUNDERSTORMS AFTER MIDNIGHT.
IN RETURN FLOW DURING THE NIGHT...THE 00Z NAM SHOWED AN INCREASE IN
BOUNDARY LAYER. THE 06Z NAM BACKED OFF THAT SOLUTION. WAS THINKING
OF PUTTING IN PATCHY FOG. BUT NOW WILL NOT AND WILL ONLY INCREASE
CLOUD COVER.
TUESDAY/TUESDAY NIGHT...WHATEVER STRATUS IS AROUND IS GONE BY LATE
MORNING. AT THIS TIME WILL LEAVE THE MENTION OF ANY THUNDERSTORMS
OUT DURING THE MORNING SINCE THIS IS UNCERTAIN AND IT LOOKS LIKE
WHAT LITTLE PRECIPITATION THERE IS WILL BE TO OUR EAST.
MODELS INDICATE THAT SOME KIND OF JET LIFT WILL BE AROUND THROUGH
THE ENTIRE DAY WITH SOME SHIFT TOWARD THE WESTERN PORTION OF THE
AREA LATE IN THE DAY. DURING THE NIGHT...SOME KIND OF JET
LIFT...MAINLY THE RIGHT REAR QUADRANT...MOVES FROM THE WESTERN AND
CENTRAL PORTION OF THE AREA IN THE EVENING INTO THE EASTERN PORTION
DURING THE OVERNIGHT HOURS.
AT THE SAME TIME THE MID LEVEL RIDGE BUILDS INTO THE AREA WITH RIDGE
ROUGHLY CENTERED OVER THE CENTRAL AND WESTERN PORTIONS OF OUR AREA.
MODELS WANT TO TRY TO PUSH A 700 MB SHORTWAVE INTO THE WESTERN
PORTION DURING THE AFTERNOON AND OVERNIGHT HOURS. BECAUSE A COUPLE
OF THE MODELS WANT TO PUT A BOUNDARY ACROSS THE CENTER OF OUR
AREA...UNDERNEATH A RIDGE WHICH DOES SEEM REASONABLE AT THIS
TIME...THOSE MODELS WANT TO PRODUCE PRECIPITATION OVER THE AREA. IF
ANY PRECIPITATION WOULD DEVELOP TO OUR WEST...NOT SURE HOW FAR EAST
IT WOULD GET DUE TO THE SLOW STORM MOTION.
IT IS A LITTLE DISCONCERTING THAT A NUMBER OF MODELS ARE PRODUCING
LIGHT QPF IN A SCENARIO WITH VERY LITTLE LIFT. SO AS NOT TOO WAFFLE
WILL KEEP THE THUNDERSTORMS OUT OF THE FORECAST BUT THIS PERIOD WILL
NEED TO BE LOOKED AT CLOSE AGAIN.
MODELS ARE ALL OVER THE PLACE WITH WHAT TO DO AT THE SURFACE. THE
GFS...CANADIAN AND TO A LESSER EXTENT THE ECMWF WANT TO DRAPE A
BOUNDARY ACROSS OUR AREA WITH EAST WINDS ACROSS A MAJORITY OF OUR
AREA. OTHER MODELS HAVE SOUTHEASTERLY WINDS. DID NOT WANT TO WARM UP
THINGS TOO MUCH...ESPECIALLY AS MUCH AS THE GFS/MAV WANTED TO
DO...WITH OTHER GUIDANCE COOLER. WENT TOWARD THAT COOLER GUIDANCE.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 406 AM MDT SUN AUG 23 2015
WEST TO NORTHWEST FLOW ALOFT WILL CONTINUE AS THE UPPER LEVEL RIDGE
MOVES SOUTH AND WEST OF THE REGION IN THE BEGINNING OF THE EXTENDED
PERIOD. SHOWERS AND THUNDERSTORMS CANNOT BE RULED OUT WEDNESDAY
NIGHT THROUGH THE WEEKEND AS PERTURBATIONS MOVE ALONG THE RIDGE AND
THE HEIGHT FIELD APPEARS TO WEAKEN.
MODELS HAVE BEEN HINTING THAT A STRONGER WAVE WILL SLOWLY MOVE ALONG
THE PERIPHERY OF THE RIDGE FROM COLORADO/WYOMING SOUTHEAST INTO THE
HIGH PLAINS WEDNESDAY NIGHT THROUGH FRIDAY AS MOISTURE INCREASES.
THIS LOOKS TO GENERATE PRECIP CHANCES DURING THIS TIME FRAME WITH
THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS ON THURSDAY AND
THURSDAY NIGHT. MOSTLY DRY CONDITIONS RETURN IN TIME FOR THE WEEKEND
AS THE RIDGE MOVES EASTWARD TOWARDS THE PLAINS BEHIND THE
DISTURBANCE. STRENGTH OF THE RIDGE WILL DETERMINE IF THESE PRECIP
CHANCES HOLD UP AS THE PERIOD GETS CLOSER.
A DECREASE IN TEMPERATURES IS CURRENTLY EXPECTED WEDNESDAY THROUGH
THE END OF THE WORK WEEK WITH HIGHS IN THE LOW TO MID 80S ON FRIDAY
BEFORE INCREASING OVER THE WEEKEND. LOW TEMPERATURES WILL FOLLOW
SUITE...DROPPING INTO THE MID 50S TO LOW 60S BY FRIDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1110 AM MDT SUN AUG 23 2015
VFR CONDITIONS ANTICIPATED AT BOTH SITES OVER THE NEXT 24 HOURS.
WITH A DRY ATMOSPHERE IN PLACE...SURFACE HIGH PRESSURE SLIDING
THROUGH AND A STOUT INVERSION...DO NOT ANTICIPATE ANY
PRECIPITATION. MID/UPPER CLOUDS MAY PASS THROUGH TODAY BEFORE
CLEAR SKIES BECOME DOMINANT TONIGHT. SOUTH WINDS RETURN LATE THIS
AFTERNOON AS A LEE TROUGH DEVELOPS ALONG THE COLORADO FRONT RANGE
AND SURFACE HIGH PRESSURE EXITS TO THE EAST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...JBH
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
601 PM EDT SUN AUG 23 2015
...UPDATED AVIATION DISCUSSION...
...FORECAST UPDATE...
ISSUED AT 455 PM EDT SUN AUG 23 2015
LATEST AMDAR DATA OUT OF KSDF INDICATE A FAIRLY STOUT CAP AT 700
MB...MORE REPRESENTATIVE OF THE CURRENT RUC FORECAST SOUNDING FOR
THIS HOUR THAN THE NAM. THAT SAME MODEL...AS WELL AS THE LATEST HRRR
TRY TO GET A SMALL LINE OF SCATTERED STORMS INTO OUR NORTH AND
NORTHEAST AFTER 23Z...CLOSE TO THE COLD FRONT. HAVE TRIMMED POPS
SOME TO ACCOUNT FOR THESE LOCATIONS. DRY AIR IN THE MID LEVELS AS
WELL AS NEAR THE SURFACE COULD MEAN SOME STRONGER WIND GUSTS OUT OF
THESE STORMS.
.SHORT TERM (NOW THROUGH MONDAY NIGHT)...
ISSUED AT 304 PM EDT SUN AUG 23 2015
AN UPPER LEVEL CLOSED LOW AND ASSOCIATED SURFACE LOW WILL SLOWLY
MOVE ACROSS SOUTHERN CANADA THROUGH THE SHORT TERM PERIOD, JUST TO
THE NORTH OF THE GREAT LAKES REGION. A COLD FRONT ASSOCIATED WITH
THIS SYSTEM WILL SWING THROUGH THE LOWER OHIO VALLEY THIS EVENING
INTO THE OVERNIGHT HOURS.
THE MAIN QUESTION FOR LATE THIS AFTERNOON INTO THE EVENING HOURS
WILL BE WHETHER STORMS WILL DEVELOP JUST AHEAD OF THE COLD FRONT AND
HOW STRONG THESE STORMS WILL BE. MUCH OF THE GUIDANCE CONTINUES TO
SHOW ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP AROUND 23-
0Z ACROSS THE WESTERN PORTION OF THE FORECAST AREA AND MOVE EASTWARD
THROUGH THE EVENING. AHEAD OF THE FRONT THERE WILL BE A CORRIDOR OF
INSTABILITY WITH 1000+ J/KG MUCAPE ACROSS WEST CENTRAL KY AND
SOUTHERN IN. IN ADDITION, THERE WILL BE BETTER EFFECTIVE SHEAR OF
POTENTIALLY 30 KNOTS OR SO ACROSS SOUTHERN INDIANA. THIS WILL WEAKEN
QUICKLY AFTER 0Z AND THE INSTABILITY WILL DECREASE. THEREFORE, THERE
IS A SMALL WINDOW OF OPPORTUNITY ALONG AND NORTH OF THE OHIO RIVER
WHERE SOME STRONG STORMS COULD DEVELOP. THE THREAT FROM ANY STRONGER
STORMS WOULD BE DAMAGING WIND GUSTS. THIS THREAT SHOULD DIMINISH
QUICKLY INTO THE EVENING AS WE LOSE THE SHEAR AND INSTABILITY.
THEREFORE, THINK MUCH OF CENTRAL KY WILL ONLY SEE SHOWERS AND
ISOLATED THUNDERSTORMS. HAVE KEPT COVERAGE FAIRLY LOW AS WELL.
STORMS SHOULD MOVE OUT OF EAST CENTRAL KENTUCKY BY 06Z OR SO AS THE
FRONT MOVES THROUGH THE REGION. MUCH DRIER AND COOLER AIR WILL
FILTER IN BEHIND THE FRONT. SKIES TOMORROW AND TOMORROW NIGHT SHOULD
BE MOSTLY CLEAR. LOWS TONIGHT WILL RANGE FROM THE MID 50S TO MID 60S
AND WILL DEPEND SOMEWHAT ON HOW FAST THE COLD AIR MOVES IN BEHIND
THE FRONT. HIGHS TOMORROW WILL BE QUITE A BIT COOLER IN THE UPPER
70S WITH LOWS TOMORROW NIGHT DIPPING INTO THE MID TO UPPER 50S.
.LONG TERM (TUESDAY THROUGH SUNDAY)...
ISSUED AT 305 PM EDT SUN AUG 23 2015
SFC HIGH PRESSURE AND A BROAD TROUGH OVER THE EASTERN CONUS
ASSOCIATED WITH A STRONG UPPER LOW OVER SOUTHERN CANADA WILL BRING
COOL, UNSEASONABLY DRY WEATHER FOR TUES-THU. HIGHS WILL RANGE FROM
THE MID 70S TO AROUND 80 WITH LOWS IN THE 50S TO AROUND 60. SOME OF
THE COLDEST LOCATIONS COULD TOUCH THE UPPER 40S WED MORNING.
BY THE END OF THE WEEK AND INTO THE WEEKEND, THIS PATTERN WILL BREAK
DOWN AS THE UPPER LOW EXITS CANADA TO THE EAST RESULTING IN A LESS
AMPLIFIED PATTERN OVER THE CONUS. WARM AIR WILL PUSH BACK NORTH
INTO THE OHIO VALLEY FOR THE END OF THE WEEK AND THROUGH THE WEEKEND
WITH HIGHS RISING INTO THE LOW TO MID 80S FRI-SUN. LOW TEMPS WILL
RANGE THROUGH THE 60S. BY THE WEEKEND WE MAY SEE A SHOT AT SOME
SHOWERS/STORMS DEPENDING ON IF WE ENTER MORE OF A NW FLOW WITH MCS`S
(GFS SOLN) OR IF A STRONG RIDGE QUICKLY BUILDS IN OVER THE OHIO
VALLEY WHICH MAY LEAVE US MORE DRY AND WARMER (ECMWF SOLN).
&&
.AVIATION (00Z TAF UPDATE)...
ISSUED AT 600 PM EDT SUN AUG 23 2015
HAVE A THIN LINE OF SHOWERS JUST WEST OF KSDF THIS HOUR. STILL NOT
CONFIDENT IN ITS SURVIVAL TO THE TERMINAL BASED ON LATEST AMDAR
SOUNDINGS...BUT WILL KEEP IN VICINITY STORMS FOR A FEW HOURS AT THE
BEGINNING OF THE TAFS. THINK THE LINE WILL BE WEAKER BY THE TIME IT
REACHES KBWG/KLEX...SO AS IN THE PREVIOUS FORECAST KEEPING THEM
SHOWERS ONLY. WILL AMEND AS WE SEE HOW CELLS DEVELOP. SKIES SHOULD
CLEAR QUICKLY BEHIND THE FRONT...WITH WINDS SWITCHING TO
NORTHWESTERLY FOR THE REST OF THE PERIOD.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........RJS
SHORT TERM.....EER
LONG TERM......AMS
AVIATION.......RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
456 PM EDT SUN AUG 23 2015
...FORECAST UPDATE...
ISSUED AT 455 PM EDT SUN AUG 23 2015
LATEST AMDAR DATA OUT OF KSDF INDICATE A FAIRLY STOUT CAP AT 700
MB...MORE REPRESENTATIVE OF THE CURRENT RUC FORECAST SOUNDING FOR
THIS HOUR THAN THE NAM. THAT SAME MODEL...AS WELL AS THE LATEST HRRR
TRY TO GET A SMALL LINE OF SCATTERED STORMS INTO OUR NORTH AND
NORTHEAST AFTER 23Z...CLOSE TO THE COLD FRONT. HAVE TRIMMED POPS
SOME TO ACCOUNT FOR THESE LOCATIONS. DRY AIR IN THE MID LEVELS AS
WELL AS NEAR THE SURFACE COULD MEAN SOME STRONGER WIND GUSTS OUT OF
THESE STORMS.
.SHORT TERM (NOW THROUGH MONDAY NIGHT)...
ISSUED AT 304 PM EDT SUN AUG 23 2015
AN UPPER LEVEL CLOSED LOW AND ASSOCIATED SURFACE LOW WILL SLOWLY
MOVE ACROSS SOUTHERN CANADA THROUGH THE SHORT TERM PERIOD, JUST TO
THE NORTH OF THE GREAT LAKES REGION. A COLD FRONT ASSOCIATED WITH
THIS SYSTEM WILL SWING THROUGH THE LOWER OHIO VALLEY THIS EVENING
INTO THE OVERNIGHT HOURS.
THE MAIN QUESTION FOR LATE THIS AFTERNOON INTO THE EVENING HOURS
WILL BE WHETHER STORMS WILL DEVELOP JUST AHEAD OF THE COLD FRONT AND
HOW STRONG THESE STORMS WILL BE. MUCH OF THE GUIDANCE CONTINUES TO
SHOW ISOLATED TO SCATTERED SHOWERS AND STORMS WILL DEVELOP AROUND 23-
0Z ACROSS THE WESTERN PORTION OF THE FORECAST AREA AND MOVE EASTWARD
THROUGH THE EVENING. AHEAD OF THE FRONT THERE WILL BE A CORRIDOR OF
INSTABILITY WITH 1000+ J/KG MUCAPE ACROSS WEST CENTRAL KY AND
SOUTHERN IN. IN ADDITION, THERE WILL BE BETTER EFFECTIVE SHEAR OF
POTENTIALLY 30 KNOTS OR SO ACROSS SOUTHERN INDIANA. THIS WILL WEAKEN
QUICKLY AFTER 0Z AND THE INSTABILITY WILL DECREASE. THEREFORE, THERE
IS A SMALL WINDOW OF OPPORTUNITY ALONG AND NORTH OF THE OHIO RIVER
WHERE SOME STRONG STORMS COULD DEVELOP. THE THREAT FROM ANY STRONGER
STORMS WOULD BE DAMAGING WIND GUSTS. THIS THREAT SHOULD DIMINISH
QUICKLY INTO THE EVENING AS WE LOSE THE SHEAR AND INSTABILITY.
THEREFORE, THINK MUCH OF CENTRAL KY WILL ONLY SEE SHOWERS AND
ISOLATED THUNDERSTORMS. HAVE KEPT COVERAGE FAIRLY LOW AS WELL.
STORMS SHOULD MOVE OUT OF EAST CENTRAL KENTUCKY BY 06Z OR SO AS THE
FRONT MOVES THROUGH THE REGION. MUCH DRIER AND COOLER AIR WILL
FILTER IN BEHIND THE FRONT. SKIES TOMORROW AND TOMORROW NIGHT SHOULD
BE MOSTLY CLEAR. LOWS TONIGHT WILL RANGE FROM THE MID 50S TO MID 60S
AND WILL DEPEND SOMEWHAT ON HOW FAST THE COLD AIR MOVES IN BEHIND
THE FRONT. HIGHS TOMORROW WILL BE QUITE A BIT COOLER IN THE UPPER
70S WITH LOWS TOMORROW NIGHT DIPPING INTO THE MID TO UPPER 50S.
.LONG TERM (TUESDAY THROUGH SUNDAY)...
ISSUED AT 305 PM EDT SUN AUG 23 2015
SFC HIGH PRESSURE AND A BROAD TROUGH OVER THE EASTERN CONUS
ASSOCIATED WITH A STRONG UPPER LOW OVER SOUTHERN CANADA WILL BRING
COOL, UNSEASONABLY DRY WEATHER FOR TUES-THU. HIGHS WILL RANGE FROM
THE MID 70S TO AROUND 80 WITH LOWS IN THE 50S TO AROUND 60. SOME OF
THE COLDEST LOCATIONS COULD TOUCH THE UPPER 40S WED MORNING.
BY THE END OF THE WEEK AND INTO THE WEEKEND, THIS PATTERN WILL BREAK
DOWN AS THE UPPER LOW EXITS CANADA TO THE EAST RESULTING IN A LESS
AMPLIFIED PATTERN OVER THE CONUS. WARM AIR WILL PUSH BACK NORTH
INTO THE OHIO VALLEY FOR THE END OF THE WEEK AND THROUGH THE WEEKEND
WITH HIGHS RISING INTO THE LOW TO MID 80S FRI-SUN. LOW TEMPS WILL
RANGE THROUGH THE 60S. BY THE WEEKEND WE MAY SEE A SHOT AT SOME
SHOWERS/STORMS DEPENDING ON IF WE ENTER MORE OF A NW FLOW WITH MCS`S
(GFS SOLN) OR IF A STRONG RIDGE QUICKLY BUILDS IN OVER THE OHIO
VALLEY WHICH MAY LEAVE US MORE DRY AND WARMER (ECMWF SOLN).
&&
.AVIATION (18Z TAF UPDATE)...
ISSUED AT 114 PM EDT SUN AUG 23 2015
DRY CONDITIONS WITH SOUTHWESTERLY WINDS ARE EXPECTED THROUGH THE
REMAINDER OF THE AFTERNOON. FOR THIS EVENING A COLD FRONT WILL
APPROACH AND MOVE THROUGH THE TAF SITES. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS FRONT. SDF STILL LOOKS
TO STAND THE BEST CHANCE TO SEE ANY THUNDERSTORMS THIS EVENING SO
WILL PUT VCTS IN THERE. OTHERWISE THE LINE WILL BE WEAKENING AS IT
MOVES THROUGH LEX AND BWG AND CHANCES OF THUNDERSTORMS SEEM SLIM, SO
WILL CARRY VCSH. IN THE WAKE OF THE FRONT SKIES WILL CLEAR QUICKLY.
WINDS WILL BE OUT OF THE NORTHWEST AT 5-7 KNOTS TOMORROW.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........RJS
SHORT TERM.....EER
LONG TERM......AMS
AVIATION.......EER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
629 PM EDT SUN AUG 23 2015
.SYNOPSIS...
A FRONTAL BOUNDARY WILL LIFT NORTHWARD ACROSS THE REGION OVERNIGHT
INTO MONDAY. A SLOW MOVING COLD FRONT WILL APPROACH MONDAY NIGHT
THROUGH TUESDAY...THEN BEGIN TO CROSS THE REGION TUESDAY NIGHT
THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
606 PM UPDATE: CHGS THIS UPDATE INCLUDE MENTIONING HEAVIER
SHWRS...ISOLD TSTMS AND PATCHY FOG ACROSS THE NRN HLF THE FA FOR
LATER TNGT AND THEN INCREASING CVR OF FOG OVR COASTAL AND INTERIOR
DOWNEAST PTNS OF THE FA FOR LATE TNGT.
RADAR CONTS TO SHOW SHWRS AND OCNL ISOLD TSTMS MOVG N ALG THE
LEADING EDGE OF A SFC WARM FRONT. MOST MODEL GUIDANCE SUGGESTS
CONTD NNW PROGRESSION OF THIS ACTIVITY INTO THE REST OF THE FA
LATER TNGT...WITH SOME UNCERTAINTY OF SHWR INTENSITY...WITH THE
LATEST HRRR FCST HRLY SIM RADAR REF INITIALLY OVERDONE BASED
ON LATEST ACTUAL RADAR REF RETURNS. SO FOR NOW...WILL RELY ON
LONGER RANGE MODELS WHICH ALSO SHOW AN INCREASE IN SHWR CVRG
AND PERHAPS INTENSITY ACROSS THE N LATER TNGT...BUT FOR NOW WILL
KEEP MAX POPS IN THE HI LIKELY CAT.
OTHERWISE...FCST HRLY TEMPS WERE UPDATED THRU THE OVRNGT TO MSLY
UNCHGD FCST LOWS MON MORN AT 6 AM BASED ON ACTUAL OBSVD HI TEMPS
AND 5 PM HRLY TEMPS. ADJUSTMENTS TO HI TRRN MAX/MIN TEMPS WERE
ALSO MADE THRU THE REST OF THE FCST.
ORGNL DISC: SHOWERS AND ISOLATED THUNDERSTORMS ARE GRADUALLY
BECOMING MORE NUMEROUS ACROSS PORTIONS OF DOWNEAST MAINE THIS
AFTERNOON, WHICH WILL CONTINUE INTO THE EVENING HOURS. THESE
SHOWERS ARE ASSOCIATED WITH A FRONTAL BOUNDARY WHICH WILL LIFT
NORTHWARD ACROSS THE STATE THIS EVENING AND OVERNIGHT. THERE`S
LOTS OF MOISTURE ON THE SOUTH SIDE OF THE BOUNDARY, WITH PWATS
ALREADY EXCEEDING 1.75 INCHES ALONG THE COAST. AS SUCH, HEAVY RAIN
WILL BE A CONCERN THROUGH THE EVENING HOURS. IN ADDITION, THE FLOW
AT THE SURFACE AND ALOFT IS FAIRLY WEAK, SO THE INDIVIDUAL CELLS
WILL BE SLOW-MOVING. ALTHOUGH SURFACE INSTABILITY WILL WANE AFTER
SUNSET, MODEL GUIDANCE INDICATES THERE`LL ENOUGH ELEVATED
INSTABILITY TO ALLOW FOR THE RISK OF THUNDER TO CONTINUE.
FOR MONDAY...THE BOUNDARY WILL LIFT NORTH OF THE SAINT JOHN VALLEY,
AND EXPECT SHOWERS WILL BE ONGOING AT DAYBREAK, ESPECIALLY OVER
NORTHERN MAINE. AN UPPER LEVEL LOW WILL BEGIN TO APPROACH FROM THE
GREAT LAKES REGION DURING THE DAY. THIS PUTS NORTHERN NEW ENGLAND IN
AN AREA OF UPPER LEVEL DIFFLUENCE, WHICH COMBINED WITH PLENTIFUL
MOISTURE WILL KEEP SCATTERED SHOWERS AROUND THROUGH THE DAY. SB
CAPES OF 500-1000 J/KG WILL BE ENOUGH TO ALLOW FOR THUNDERSTORMS.
HIGHS WILL BE IN THE MID 70S TO AROUND 80.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AN UPPER LEVEL TROF WILL REMAIN WEST OF THE REGION...WITH UPPER
LEVEL RIDGING ACROSS THE MARITIMES...MONDAY NIGHT THROUGH
WEDNESDAY. A COLD/OCCLUDED FRONT WILL MOVE SLOWLY EAST ACROSS NEW
ENGLAND MONDAY NIGHT THROUGH TUESDAY...THEN BEGIN TO CROSS THE
FORECAST AREA TUESDAY NIGHT THROUGH WEDNESDAY. UNSETTLED
CONDITIONS WILL OCCUR ACROSS THE REGION IN ADVANCE OF THE FRONT
AND ALONG THE FRONT. GENERALLY EXPECT MOSTLY CLOUDY SKIES ALONG
WITH A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE REGION
MONDAY NIGHT THROUGH TUESDAY. SHOWER/THUNDERSTORM CHANCES WILL
THEN INCREASE TUESDAY NIGHT AND WEDNESDAY ALONG THE FRONT.
HOWEVER...THE EXACT TIMING OF THE FRONT AND LOCATION OF THE
HEAVIER PRECIPITATION IS STILL UNCERTAIN. TEMPERATURES WILL BE AT
NEAR NORMAL LEVELS TUESDAY/WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
A SLOW MOVING UPPER LEVEL TROUGH WILL TRUDGE THROUGH NORTHERN NEW
ENGLAND WEDNESDAY NIGHT INTO FRIDAY WITH SHOWERS AND ISOLATED
THUNDERSTORMS. EXPECT HIGH TEMPERATURES TO BE SLIGHTLY BELOW TO
NEAR NORMAL WITH LOW TEMPERATURES NEAR TO SLIGHTLY ABOVE NORMAL DUE
TO EXTENSIVE CLOUD COVER.
SEASONALLY STRONG ZONAL/WESTERLY FLOW MOVES INTO THE REGION FOR
FRIDAY AND NEXT WEEKEND. A BAROCLINIC ZONE SEPARATES A LATE SUMMER
AIRMASS OVER THE MID ATLANTIC AND SOUTHERN NEW ENGLAND FROM A MUCH
COOLER REGIME ACROSS QUEBEC. THE MEDIUM RANGE MODELS BRING A SERIES
OF DISTURBANCES WITH DISTINCT BAROCLINIC LEAVES NEAR NORTHERN MAINE
DURING THIS TIME PERIOD. THE EXACT POSITIONS OF THESE LEAVES WILL
DETERMINE WHETHER THE REGION EXPERIENCES MOSTLY DRY OR UNSETTLED
RAINY WEATHER. FORECAST CONFIDENCE IS LOW 5 TO 7 DAYS OUT.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: VFR CONDITIONS WILL PREVAIL THROUGH ABOUT 00Z, THOUGH
LOCAL MVFR WILL BE POSSIBLE IN SHOWERS/ISOLATED THUNDERSTORMS AT
KBGR AND KBHB UNTIL THEN. THEREAFTER, THE PRECIPITATION WILL LIFT
INTO NORTHERN MAINE WITH WIDESPREAD MVFR AT THE NORTHERN SITES.
THE SOUTHERN TERMINALS WILL DROP TO IFR/POSSIBLE LIFR AFTER 06Z IN
FOG. CONDITIONS WILL IMPROVE TO MVFR AFTER 14Z MONDAY, AND THE
NORTHERN SITES WILL REMAIN MVFR AS WELL.
SHORT TERM: VARIABLE CONDITIONS WILL OCCUR WITH ANY
SHOWERS/THUNDERSTORMS OR PATCHY FOG MONDAY NIGHT THROUGH THURSDAY.
OTHERWISE...VFR CONDITIONS ARE EXPECTED MONDAY NIGHT THROUGH
THURSDAY. VFR CONDITIONS ARE EXPECTED FRIDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES WILL BE NEEDED OVER THE WATERS TONIGHT OR
MONDAY. SWELLS WILL BUILD TO AROUND 4 FEET THIS EVENING AND
OVERNIGHT, BUT SEAS ARE EXPECTED TO REMAIN BELOW 5 FEET. FOG WILL
ONCE AGAIN RESTRICT VISIBILITY OVER THE WATERS OVERNIGHT INTO
MONDAY MORNING.
SHORT TERM: WINDS/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS MONDAY NIGHT THROUGH WEDNESDAY. VISIBILITIES WILL BE
REDUCED IN SHOWERS AND FOG LATER TUESDAY THROUGH WEDNESDAY. COULD
ALSO HAVE A CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORCROSS
LONG TERM...OKULSKI
AVIATION...VJN/NORCROSS
MARINE...VJN/NORCROSS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1258 PM EDT SUN AUG 23 2015
.SYNOPSIS...
THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS A WARM FRONT
TODAY THROUGH MONDAY. A SLOW MOVING FRONTAL SYSTEM IS EXPECTED
APPROACH THE REGION FROM THE WEST ON TUESDAY AND CROSS THE AREA ON
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1255 PM UPDATE...A BAND OF SHOWERS WITH ISOLATED THUNDER IS SLOWLY
SLIDING NORTHWARD THROUGH SOUTHERN PENOBSCOT AND INTO SOUTHERN
PISCATAQUIS COUNTIES. EAST OF THIS AREA, ACTIVITY HAS BEEN SLOW TO
DEVELOP. HOWEVER, THERE`S ANOTHER AREA OF SHOWERS AND
THUNDERSTORMS THAT HAVE POPPED UP ALONG COASTAL NEW BRUNSWICK.
EXPECT THAT THIS CONVECTION WILL CONTINUE TO DEVELOP WESTWARD THIS
AFTERNOON. THE LATEST SPC MESOANALYSIS SHOWS SB CAPES ACROSS
DOWNEAST MAINE IS NOW 500-1500 J/KG, SO PLENTY OF INSTABILITY FOR
THIS CONVECTION TO FIRE UP. PWATS IN THIS AREA ARE ALSO
INCREASING TO ABOVE 1.5 INCHES. AS SUCH EXPECT ANY SHOWERS WILL
HAVE THE CABABILITY OF PRODUCING HEAVY RAINFALL. MINIMAL FLOW
MEANS THEY`LL BE SLOW MOVING AS WELL. HAVE MADE ADJUSTMENTS TO
POPS, SKY, AND TEMPS TO BRING ALL INTO BETTER AGREEMENT WITH
CURRENT RADAR/SATELLITE/SURFACE OBS TRENDS.
PREVIOUS DISCUSSION...SURFACE ANALYSIS SHOWED TROF OR WEAK
FRONTAL BOUNDARY DRAPED ACROSS THE DOWNEAST REGION. THIS FEATURE
IS FORECAST TO LIFT NORTHWARD TODAY W/MORE HUMID AIR OVERSPREADING
THE REGION AS LOW PRES LIFTS NE ACROSS THE WESTERN ATLC. THE 00Z
NAM AND HRRR 3KM HAD THINGS INITIALIZED WELL. USED THIS BLEND FOR
TODAY`S FORECAST W/PRECIP LIFTING FROM S TO N.
SHOWERS WILL MOVE FROM S TO N TODAY. HIGH PRES ANCHORED OVER THE
NW ATLC WILL ACT AS A BLOCK INITIALLY AS PRECIP DIES OUT HITTING A
DRY AND STABLE AIRMASS IN PLACE ACROSS THE NORTH AND WEST. FURTHER
S ACROSS CENTRAL AND DOWNEAST AREAS, SOUNDING DATA SHOWED THE
COLUMN MOISTENING THROUGH 700MBS W/INCREASING INSTABILITY. SB
CAPES OF 500-1000 JOULES ARE FORECAST TO SETUP THIS AFTERNOON
ACROSS THE AFOREMENTIONED AREAS. PWATS ARE 1.7+ W/LIS DOWN TO -2
TO -3. 0-6KM SHEAR IS WEAK < 10 KTS. A WARM CLOUD LAYER W/HIGH
FREEZING LEVELS(13-14K FT) WILL LEAD TO LOADING OF PRECIP
W/POTENTIAL FOR HEAVY TO TORRENTIAL RAINFALL IN SPOTS. DECIDED TO
STAY W/TSTMS THIS AFTERNOON INTO THE EVENING AND ADDED HEAVY
RAINFALL WORDING.
SHOWERS AND SOME TSTMS ARE EXPECTED TO SPREAD INTO NORTHERN AND
WESTERN MAINE TONIGHT. SOUNDING DATA SHOWED MOST OF THE CONVECTION
TO BE ELEVATED W/THE HIGHEST THREAT ACROSS THE HOULTON AND
MILLINOCKET REGION W/LESS INSTABILITY FURTHER N. ONCE AGAIN HEAVY
RAIN THREAT CONTINUES. DOWNEAST AND COASTAL AREAS WILL BECOME MORE
STABLE W/FOG AND DRIZZLE. USED A CONSENSUS BLEND ON THE QPF DUE
TO LOW CONFIDENCE IN PLACEMENT OF HEAVIER RAINFALL AMOUNTS. SOME
AREAS COULD DEFINITELY PICK AN INCH OR MORE OF RAIN IN TSTMS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
UNSETTLED WX PATTERN CONTINUES FOR THE START OF THE WORK WEEK.
EXPECT THE CHANCE FOR SHOWERS AND AFTERNOON THUNDERSTORMS BOTH
MONDAY AND AGAIN ON TUESDAY AS A TROF OF LOW PRESSURE TRACKS
SLOWLY EAST FROM THE GREAT LAKES REGION. HIGH TEMPERATURES BOTH
MONDAY AND TUESDAY WILL RANGE FROM THE MID TO UPPER 70S. IT WILL
ALSO CONTINUE TO FEEL ON THE MUGGY SIDE WITH DEW POINT EXPECTED TO
REMAIN IN THE 60S BOTH DAYS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
TUESDAY NIGHT WILL SEE THE THREAT FOR SHOWERS AND EVENING
THUNDERSTORMS AS A LEAD SHORT WAVE AHEAD OF THE APPROACHING UPPER
TROF MOVES ACROSS THE REGION. UNSETTLED WEATHER WITH CONTINUED
CHANCES FOR SHOWERS AND AFTERNOON THUNDERSTORMS WILL CONTINUE INTO
THURSDAY EVENING AS THE TROF SWINGS ACROSS THE REGION. HIGH
PRESSURE WILL BUILD IN FOR FRIDAY. A COLD FRONT WILL CROSS THE
REGION SATURDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: IFR/LIFR FOR SOME OF THE TERMINALS(KPQI-KHUL) THIS
MORNING DUE TO FOG. ACROSS KBGR AND KBHB, VFR ATTM. EXPECTING KBGR
AND KBHB TO DROP TO MVFR AND THEN IFR LATER THIS MORNING INTO THE
AFTERNOON AND HOLD AT IFR TONIGHT. THE NORTHERN TERMINALS WILL
IMPROVE TO VFR AFTER 12Z AND STAY THERE THROUGH THE AFTERNOON.
MVFR CONDITIONS ARRIVE ACROSS KHUL THIS EVENING AND THEN TO IFR BY
MIDNIGHT W/KPQI-KCAR-KFVE DROPPING TO MVFR BY LATE EVENING AND
THEN IFR OVERNIGHT. TSTMS W/CLOUD TO GROUND LIGHTNING AND HEAVY
RAINFALL ARE POSSIBLE THIS AFTERNOON INTO TONIGHT.
SHORT TERM: VFR CONDITIONS WILL PREVAIL MOST OF THE TIME BUT
MVFR/IFR IS POSSIBLE IN PATCHY NIGHTTIME/EARLY MORNING FOG AS WELL
AS SCT SHOWERS/TSTMS.
&&
.MARINE...
NEAR TERM: A 3 FOOT SWELLS OUT ON THE WATERS ATTM IS EXPECTED TO
BUILD TO AROUND 4 FT THIS AFTERNOON. SWELLS ARE EXPECTED TO BUILD
TO A RANGE OF 4-5 FT TONIGHT. WINDS WILL REMAIN LIGHT 10 KTS OR
LESS RIGHT INTO TONIGHT. FOG WILL HAMPER NAVIGATION FROM TIME TO
TIME. TSTMS ARE POSSIBLE LATER THIS AFTERNOON INTO THE EVENING.
SHORT TERM: WIND/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY
LEVEL.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HASTINGS/HEWITT/DUDA
MARINE...HASTINGS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
444 PM EDT SUN AUG 23 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 401 PM EDT SUN AUG 23 2015
12Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW POTENT SHRTWV/
CUTOFF H5 LO LIFTING NORTH OF THE MN ARROWHEAD THIS AFTERNOON INTO
ONTARIO. THIS POTENT SYSTEM CAUSED 00Z-12Z H5 HGT FALLS OF 160M AT
KINL AND 120-140M HGT FALLS OVER UPPER MI. STRONG UPPER
DIFFLUENCE/DPVA AND DEEP LAYER QVECTOR CONVERGENCE AHEAD OF THIS
FEATURE AND AHEAD OF THE ASSOCIATED COLD FRONTAL PASSAGE RESULTED IN
A LINE OF HEAVY SHOWERS AND STRONG STORMS MOVING ACROSS UPPER MI
THIS MORNING INTO THE AFTERNOON HOURS. THE MAIN LINE OF SHOWERS HAS
EXITED E OF MOST OF THE CWA...BUT THERE WAS STILL SOME LINGERING
SCATTERED SHOWERS AHEAD OF THE FRONTAL BOUNDARY WHICH WAS
APPROXIMATELY ALONG A LINE FROM MUNISING TO GARDEN IN PAST HOUR.
SOME SCATTERED SHOWERS WERE ALSO BEGINNING TO WORK INTO THE FAR WRN
CWA THIS PAST HOUR WITH WRAPAROUND MOISTURE MOVING IN ON BACKSIDE OF
ONTARIO LOW.
TONIGHT AND MONDAY...SCATTERED SHOWERS OVER THE EASTERN THIRD OF THE
CWA SHOULD END BETWEEN 22-00Z THIS EVENING AS FRONT EXITS THE AREA.
ATTENTION WILL THEN TURN TO WRAPAROUND MOISTURE AND STRONG COLD
ADVECTION ON THE BACKSIDE OF NEARLY VERICALLY STACKED LOW PRESSURE
SYSTEM DRIFTING SLOWLY EAST FROM ONTARIO ACROSS THE UPPER GREAT
LAKES REGION. THIS DEEPER MOISTURE AND COLD ADVECTION WILL LEAD TO
LAKE ENHANCED RAIN SHOWERS FOR AREAS DOWNWIND OF LAKE SUPERIOR IN A
WNW WIND FLOW. 8H TEMPS DROPPING TO 3C WEST AND 5-6C EAST LATE
TONIGHT IN A WESTERLY FLOW WILL LEAD TO AN INCREASE IN COVERAGE OF
LAKE EFFECT RAIN SHOWERS LATE TONIGHT OVER THE WRN U.P. AND EVEN
CARRYING INTO THE HURON MOUNTAINS AS CONVECTIVE BOUNDARY LAYER WINDS
INCREASE TOWARD 30KTS BEHIND THE SYSTEM. THE COLD ADVECTION WILL
RESULT IN LAKE DELTA-T VALUES 10-13C SUFFICIENT FOR LAKE ENHANCED
RAIN IN STRONGLY CYCLONIC WESTERLY FLOW. WILL CONTINUE LIKELY TO
CATEGORICAL POPS OVER THESE AREAS TONIGHT INTO MONDAY. WINDS VEERING
MORE NW DURING THE DAY ON MONDAY WILL BRING LAKE EFFECT RAIN SHOWERS
INTO ERN COUNTIES OF UPPER MI SO HAVE CORRESPONDINGLY BUMPED UP POPS
THERE TO HIGH LIKELY/CATEGORICAL ON MONDAY AS WELL. THE REST OF THE
CWA WILL SEE ISOLD TO SCT LAKE EFFECT SHOWERS LATE TONIGHT INTO
MONDAY.
TEMPS WILL BE DROPPING QUICKLY TONIGHT WITH THE CAA IN THE WAKE OF
THE SYSTEM. EXPECT LOWS RANGING FROM THE UPPER 40S INTERIOR WEST TO
MID 50S NEAR THE GREAT LAKES SHORELINES. MONDAY WILL FEEL MORE LIKE
OCTOBER AS TEMPS ONLY RISE A FEW DEGREES WITH MOST READINGS STAYING
IN THE 50S. RECORD LOW MAXIMUM TEMPS ON MONDAY WILL BE IN JEOPARDY
AT A NUMBER OF SITES.
DEEP MIXING FROM COLD ADVECTION WILL ALLOW FOR BREEZY CONDITIONS
ACROSS THE CWA THROUGH MUCH OF THE PERIOD. IT WILL BE WINDY OVER THE
KEWEENAW PENINSULA (ESPECIALLY THE PORTAGE CANAL) WITH THE FAVORED
WESTERLY WIND DIRECTION AND MORE UNSTABLE FLOW OFF LAKE SUPERIOR SO
EXPECT THE POTENTIAL FOR WINDS GUSTING 35-40 MPH AT SOME OF THE MORE
EXPOSED LOCATIONS OVER THE KEWEENAW.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 443 PM EDT SUN AUG 23 2015
DAMP AND FALL-LIKE CONDITIONS WILL GIVE WAY TO MODERATION TOWARD
MORE SEASONAL WEATHER BY THU INTO THE WEEKEND. A DEEP CLOSED MID-
UPPER LEVEL LOW JUST EAST OF LAKE SUPERIOR AT 00Z/TUE WILL GRAUDALLY
FILL AND MOVE TO QUEBEC BY WED. RIDGING WILL THEN PUSH BACK TOWARD
THE WESTERN LAKES BY THU INTO THE WEEKEND.
MON NIGHT INTO TUE...DEEP MOIST CYCLONIC FLOW IN THE WAKE OF THE MID
LEVEL LOW WILL BRING SCT/ISOLD -SHRA TO MOST OF THE CWA.
HOWEVER...WITH 850 MB TEMPS INTO THE 3C-5C RANGE AND LAKE WATER
TEMPS NEAR 16C...LAKE ENHANCED RAIN WILL BRING MORE SIGNFICANT
RAIN...WITH LIKELY TO CATEGORICAL POPS...TO LOCATIONS FAVORED BY WNW
LOW LEVEL FLOW SUCH AS NW UPPER MI AND AREAS EAST OF MARQUETTE.
UPSLOPE FLOW WILL ALSO HELP TO BOOST PCPN AMOUNTS OVER THE HIGHER
TERRAIN. HIGH TEMPS WILL REMAIN IN THE UPPER 50S OVER THE NW HALF TO
THE LOW AND MID 60S OVER THE SOUTH.
TUE NIGHT AND WED...AS THE MID LEVEL LOW SHIFTS TO THE EAST...MODELS
SUGGEST THAT LOW LEVEL WINDS WILL GRADUALLY VEER TO THE NNW AS 850
TEMPS CLIMB TO NEAR 7C BY 12Z/WED. THIS SHOULD BRING GREATER -SHRA
COVERAGE INTO N CNTRL UPPER MI EVEN AS THE AMOUNTS DIMINISH. EXPECT
THE PCPN TO DIMINISH AND END WED AS THE DEEP MOISTURE SHIFTS TO THE
EAST. MAX TEMPS ARE EXPECTED REBOUND BACK INTO THE MID TO UPPER 60S.
WED NIGHT INTO THU...WITH FAVORABLE RADIATIONAL COOLING CONDITIONS
AS THE SFC RIDGE BUILDS INTO THE AREA AND PWAT VALUES BLO 0.5
INCH...EXPECT INLAND MIN TEMPS INTO THE MID 40S INLAND. ABUNDANT
SUNSHINE THU SHOULD PUSH TEMPS BACK TO SEASONAL AVERAGES IN THE
LOWER TO MID 70S.
FRI-SUN...UNCERTAINTY INCREASES DUE TO MODEL DIFFERENCES IN HANDLING
THE POSITION OF THE SFC FRONT AND IMPACT OF A SHRTWV MOVING OUT OF
THE PLAINS. EXPECT TEMPS NEAR OR ABOVE NORMAL WITH HIGHS INTO THE
MID AND UPPER 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM EDT SUN AUG 23 2015
THE BAND OF SHOWERS/THUNDERSTORMS AHEAD OF A COLD FRONT HAS ALREADY
EXITED E OF THE TAF SITES. DRIER AIR IMMEDIATELY BEHIND THE COLD
FRONT HAS RESULTED IN A PERIOD OF VFR CONDITIONS AT KIWD AND KCMX IN
THE WAKE OF SHOWERS AND WILL RESULT IN A PERIOD OF VFR CONDITIONS AT
KSAW AS WELL THIS AFTERNOON. BUT AN AREA OF MOISTER LLVL AIR WRAPPING
BACK INTO THE REGION FM NRN MN WL BRING A RETURN OF MVFR CIGS THIS
AFTN AT IWD AND CMX WITH INCRSG UPSLOPE W WIND ARND DEEP LO PRES IN
NW ONTARIO. GUSTY W WINDS NEAR 30 KTS AND MVFR CONDITIONS WL
DOMINATE IWD/CMX TNGT. STRONG WINDS MAY ALSO ALLOW SOME SCT SHRA AND
PREDOMINANT MVFR CONDITIONS TO CARRY E INTO KSAW BY THIS EVENING AS
WELL DESPITE DOWNSLOPE WEST FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 401 PM EDT SUN AUG 23 2015
A FALL LIKE LOW PRESSURE SYSTEM CURRENTLY TO THE NORTH OF THE LAKE
OF THE WOODS WILL BRING WINDY CONDITIONS TO LAKE SUPERIOR THROUGH
THE FIRST HALF OF THE UPCOMING WORK WEEK AS IT SLOWLY MOVES EAST
ACROSS NORTHERN ONTARIO. GUSTY SOUTHERLY WINDS WILL CONTINUE THIS
MORNING AHEAD OF A COLD FRONT OVER WESTERN LAKE SUPERIOR...BUT AS
IT MOVES EAST ACROSS THE REST OF THE LAKE TODAY IT WILL SHIFT WINDS
TO THE WEST AND LEAD TO GALES TO 35 KNOTS FOR PORTIONS OF WESTERN
LAKE SUPERIOR THIS AFTERNOON AND EXPANDING ACROSS THE REST OF
THE WESTERN HALF OF THE LAKE TONIGHT AND CONTINUING INTO MONDAY.
WITH THE LOW SLOWLY WEAKENING MONDAY NIGHT INTO TUESDAY AS IT NEARS
JAMES BAY...THE WINDS WILL GRADUALLY DIMINISH AND TURN TO THE
NORTHWEST. HIGH PRESSURE WILL BUILD OVER THE UPPER GREAT LAKES
REGION FOR WEDNESDAY AND THURSDAY..WHICH WILL LOWER WINDS BELOW
20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 8 PM EDT /7 PM CDT/ MONDAY FOR LSZ162-263-264.
GALE WARNING FROM 2 AM TO 8 PM EDT MONDAY FOR LSZ265.
GALE WARNING FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO 5 PM EDT
/4 PM CDT/ MONDAY FOR LSZ240>244.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLB
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EDT SUN AUG 23 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 401 PM EDT SUN AUG 23 2015
12Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW POTENT SHRTWV/
CUTOFF H5 LO LIFTING NORTH OF THE MN ARROWHEAD THIS AFTERNOON INTO
ONTARIO. THIS POTENT SYSTEM CAUSED 00Z-12Z H5 HGT FALLS OF 160M AT
KINL AND 120-140M HGT FALLS OVER UPPER MI. STRONG UPPER
DIFFLUENCE/DPVA AND DEEP LAYER QVECTOR CONVERGENCE AHEAD OF THIS
FEATURE AND AHEAD OF THE ASSOCIATED COLD FRONTAL PASSAGE RESULTED IN
A LINE OF HEAVY SHOWERS AND STRONG STORMS MOVING ACROSS UPPER MI
THIS MORNING INTO THE AFTERNOON HOURS. THE MAIN LINE OF SHOWERS HAS
EXITED E OF MOST OF THE CWA...BUT THERE WAS STILL SOME LINGERING
SCATTERED SHOWERS AHEAD OF THE FRONTAL BOUNDARY WHICH WAS
APPROXIMATELY ALONG A LINE FROM MUNISING TO GARDEN IN PAST HOUR.
SOME SCATTERED SHOWERS WERE ALSO BEGINNING TO WORK INTO THE FAR WRN
CWA THIS PAST HOUR WITH WRAPAROUND MOISTURE MOVING IN ON BACKSIDE OF
ONTARIO LOW.
TONIGHT AND MONDAY...SCATTERED SHOWERS OVER THE EASTERN THIRD OF THE
CWA SHOULD END BETWEEN 22-00Z THIS EVENING AS FRONT EXITS THE AREA.
ATTENTION WILL THEN TURN TO WRAPAROUND MOISTURE AND STRONG COLD
ADVECTION ON THE BACKSIDE OF NEARLY VERICALLY STACKED LOW PRESSURE
SYSTEM DRIFTING SLOWLY EAST FROM ONTARIO ACROSS THE UPPER GREAT
LAKES REGION. THIS DEEPER MOISTURE AND COLD ADVECTION WILL LEAD TO
LAKE ENHANCED RAIN SHOWERS FOR AREAS DOWNWIND OF LAKE SUPERIOR IN A
WNW WIND FLOW. 8H TEMPS DROPPING TO 3C WEST AND 5-6C EAST LATE
TONIGHT IN A WESTERLY FLOW WILL LEAD TO AN INCREASE IN COVERAGE OF
LAKE EFFECT RAIN SHOWERS LATE TONIGHT OVER THE WRN U.P. AND EVEN
CARRYING INTO THE HURON MOUNTAINS AS CONVECTIVE BOUNDARY LAYER WINDS
INCREASE TOWARD 30KTS BEHIND THE SYSTEM. THE COLD ADVECTION WILL
RESULT IN LAKE DELTA-T VALUES 10-13C SUFFICIENT FOR LAKE ENHANCED
RAIN IN STRONGLY CYCLONIC WESTERLY FLOW. WILL CONTINUE LIKELY TO
CATEGORICAL POPS OVER THESE AREAS TONIGHT INTO MONDAY. WINDS VEERING
MORE NW DURING THE DAY ON MONDAY WILL BRING LAKE EFFECT RAIN SHOWERS
INTO ERN COUNTIES OF UPPER MI SO HAVE CORRESPONDINGLY BUMPED UP POPS
THERE TO HIGH LIKELY/CATEGORICAL ON MONDAY AS WELL. THE REST OF THE
CWA WILL SEE ISOLD TO SCT LAKE EFFECT SHOWERS LATE TONIGHT INTO
MONDAY.
TEMPS WILL BE DROPPING QUICKLY TONIGHT WITH THE CAA IN THE WAKE OF
THE SYSTEM. EXPECT LOWS RANGING FROM THE UPPER 40S INTERIOR WEST TO
MID 50S NEAR THE GREAT LAKES SHORELINES. MONDAY WILL FEEL MORE LIKE
OCTOBER AS TEMPS ONLY RISE A FEW DEGREES WITH MOST READINGS STAYING
IN THE 50S. RECORD LOW MAXIMUM TEMPS ON MONDAY WILL BE IN JEOPARDY
AT A NUMBER OF SITES.
DEEP MIXING FROM COLD ADVECTION WILL ALLOW FOR BREEZY CONDITIONS
ACROSS THE CWA THROUGH MUCH OF THE PERIOD. IT WILL BE WINDY OVER THE
KEWEENAW PENINSULA (ESPECIALLY THE PORTAGE CANAL) WITH THE FAVORED
WESTERLY WIND DIRECTION AND MORE UNSTABLE FLOW OFF LAKE SUPERIOR SO
EXPECT THE POTENTIAL FOR WINDS GUSTING 35-40 MPH AT SOME OF THE MORE
EXPOSED LOCATIONS OVER THE KEWEENAW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 312 AM EDT SUN AUG 23 2015
THE NEARLY VERTICALLY STACKED SURFACE AND UPPER LOW AT 12Z MONDAY
WILL BE SLOWLY MOVING EAST ACROSS NORTHERN ONTARIO AND WILL CONTINUE
THAT PATH THROUGH TUESDAY NIGHT BEFORE FINALLY BECOMING CAUGHT UP IN
THE NORTHERN STREAM FLOW AND QUICKLY LIFTING NORTHEAST THROUGH
QUEBEC ON WEDNESDAY/THURSDAY. THIS WILL LEAD TO A VERY FALL LIKE
START TO THE WORK WEEK WITH BREEZY WEST-NORTHWEST WINDS...PERIODS OF
LAKE EFFECT/ENHANCED RAIN AND TEMPERATURES WELL BELOW NORMAL.
WITH ABUNDANT MOISTURE WRAPPING AROUND THE UPPER/SURFACE
LOW...EXPECT PLENTY OF LOW CLOUDS (AND SCATTERED TO NUMEROUS
SHOWERS) ACROSS THE U.P. FOR MONDAY INTO AT LEAST WEDNESDAY MORNING.
THE MAIN QUESTION WILL BE HOW COLD THE 850MB TEMPS WILL BE TO THE
SOUTHWEST OF THE LOW IN ONTARIO. MODELS VARY IN THE EXACT
VALUE...WITH THE NAM THE COLDEST AT 0-1C AND THE REST IN THE 2.5-4C
RANGE FOR MONDAY AND THEN GRADUALLY WARMING THROUGH TUESDAY. THE
EXACT VALUE DOESN/T MATTER TOO MUCH...AS THE TEMPERATURES ALOFT WILL
BE COLD ENOUGH FOR LAKE ENHANCED/EFFECT RAIN WITH WESTERN LAKE
SUPERIOR TEMPERATURES AROUND 15-17C. THEREFORE...WILL SHOW LIKELY TO
DEFINITE VALUES FOR THE FAVORED WEST-NORTHWEST WIND AREAS ON MONDAY
AND TRANSITION TO MORE NORTHWESTERLY FOR MONDAY NIGHT INTO TUESDAY.
IN ADDITION...WILL HAVE THE HIGHEST POPS OVER THE FAVORED UPSLOPE
LOCATIONS FOR THE MONDAY INTO TUESDAY PERIOD (AREAS FROM THE SPINE
OF THE KEWEENAW THROUGH IRONWOOD). THAT UPSLOPE FORCING WILL BE DUE
TO THE WEST-NORTHWEST WINDS ON MONDAY AND THEN TRANSITION TO MORE
NORTHWESTERLY ON MONDAY NIGHT AS THE SURFACE-850MB LOW SHIFTS EAST
AND CLOSER TO JAMES BAY AND THE SURFACE TROUGH MOVES EAST ACROSS THE
UPPER GREAT LAKES. THAT NORTHWESTERLY LOW LEVEL FLOW WILL CONTINUE
INTO WEDNESDAY...POTENTIALLY TURNING A LITTLE MORE NORTH-NORTHWEST.
THE STRONGEST WINDS WILL OCCUR MONDAY INTO MONDAY NIGHT (GUSTS OF 20-
30KTS OVER THE WESTERN U.P.) WITH THE TIGHTEST PRESSURE GRADIENT AS
THE SURFACE LOW IS JUST TO THE NORTH OF LAKE SUPERIOR. THEN THE
WINDS WILL GRADUALLY DIMINISH TUESDAY INTO WEDNESDAY AS THE LOW
WEAKENS/BROADENS AS IT MOVES INTO NORTHEAST ONTARIO.
THE THIRD ITEM OF NOTE TO START THE WEEK WILL BE THE VERY FALL LIKE
HIGHS ACROSS THE AREA ON MONDAY. WITH PLENTY OF CLOUDS AND
SHOWERS...HAVE OPTED TO FOLLOW THE RAW MODELS FOR HIGHS ON
MONDAY...WHICH GIVES LOW-MID 50S OVER THE WEST AND MID-UPPER 50S
OVER THE EAST. THIS IS ABOUT 20 DEGREES BELOW NORMAL AND IN SOME
AREAS THEY WILL BE NEARING RECORD COLD HIGH TEMPERATURES. THE RECORD
FOR OUR OFFICE IS 56 DEGREES (1978/1971) AND WE WILL BE NEAR THAT
BOTH AT MIDNIGHT TONIGHT AND AGAIN WITH THE HIGH ON MONDAY
AFTERNOON. LOOKING AT THE TIME SHIFTED COOP DATA (NEED TO USE 8/25
VALUES)...MANY SITES HAVE RECORD VALUES IN THE 50S AND SOME OF THE
MORE NOTABLE ONES ARE...IRONWOOD 55 IN 1915...HOUGHTON 53 IN 1987
(MIDNIGHT-MIDNIGHT)...IRON MOUNTAIN 59 IN 1940...MUNISING 57 IN
1940...AND 55 IN NEWBERRY IN 1917. THUS...WITH THE GOING FORECAST
HIGH TEMPERATURES...THERE WILL BE SEVERAL SPOTS THAT WILL BE NEAR
RECORD LOW MAXIMUM VALUES. TEMPERATURES WILL WARM A FEW DEGREES FOR
TUESDAY...BUT HIGHS WILL STILL BE IN THE UPPER 50S AND LOWER 60S.
DRY AIR FROM THE HIGH BUILDING INTO THE PLAINS ON WEDNESDAY WILL
FINALLY BRING AN END TO THE PROLONGED PERIOD OF CLOUDS AND SHOWERS
FROM WEST TO EAST ON WEDNESDAY (ALTHOUGH THE CLOUDS MAY LINGER OVER
THE FAR EAST INTO THE EVENING HOURS). THAT HIGH PRESSURE RIDGE WILL
MOVE OVER THE AREA WEDNESDAY NIGHT AND REMAIN INTO THURSDAY.
CLEARING SKIES AND LIGHT WINDS ON WEDNESDAY NIGHT WILL LEAD TO A
GOOD RADIATIONAL COOLING NIGHT ACROSS THE AREA AND HAVE LOWER LOWS
SOME FROM THE PREVIOUS FORECAST (CLOSER TO THE MEX AND GEM VALUES
WHICH TEND TO PERFORM BETTER IN THOSE SITUATIONS). ABUNDANT SUNSHINE
ON THURSDAY WILL LEAD TO HIGHS RETURNING TO MORE NORMAL VALUES FOR
LATE AUGUST.
FINALLY...A COLD FRONT WILL DROP SOUTHEAST ACROSS THE UPPER GREAT
LAKES LATE THURSDAY NIGHT INTO FRIDAY...BRINGING A CHANCE FOR
SHOWERS/THUNDERSTORMS TO THE U.P.. THINK THE COVERAGE/AMOUNTS WILL
LIMITED DUE TO THE LACK OF RETURN FLOW AND EXISTING DRY AIR.
THUS...WON/T GO MORE THAN LOW CHANCE POPS FOR NOW AS THE FRONT MOVES
THROUGH. A WEAK RIDGE LOOKS TO MOVE OVER THE AREA FOR SATURDAY
BEHIND THE FRONT AND SHOULD LEAD TO A DRY DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM EDT SUN AUG 23 2015
THE BAND OF SHOWERS/THUNDERSTORMS AHEAD OF A COLD FRONT HAS ALREADY
EXITED E OF THE TAF SITES. DRIER AIR IMMEDIATELY BEHIND THE COLD
FRONT HAS RESULTED IN A PERIOD OF VFR CONDITIONS AT KIWD AND KCMX IN
THE WAKE OF SHOWERS AND WILL RESULT IN A PERIOD OF VFR CONDITIONS AT
KSAW AS WELL THIS AFTERNOON. BUT AN AREA OF MOISTER LLVL AIR WRAPPING
BACK INTO THE REGION FM NRN MN WL BRING A RETURN OF MVFR CIGS THIS
AFTN AT IWD AND CMX WITH INCRSG UPSLOPE W WIND ARND DEEP LO PRES IN
NW ONTARIO. GUSTY W WINDS NEAR 30 KTS AND MVFR CONDITIONS WL
DOMINATE IWD/CMX TNGT. STRONG WINDS MAY ALSO ALLOW SOME SCT SHRA AND
PREDOMINANT MVFR CONDITIONS TO CARRY E INTO KSAW BY THIS EVENING AS
WELL DESPITE DOWNSLOPE WEST FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 401 PM EDT SUN AUG 23 2015
A FALL LIKE LOW PRESSURE SYSTEM CURRENTLY TO THE NORTH OF THE LAKE
OF THE WOODS WILL BRING WINDY CONDITIONS TO LAKE SUPERIOR THROUGH
THE FIRST HALF OF THE UPCOMING WORK WEEK AS IT SLOWLY MOVES EAST
ACROSS NORTHERN ONTARIO. GUSTY SOUTHERLY WINDS WILL CONTINUE THIS
MORNING AHEAD OF A COLD FRONT OVER WESTERN LAKE SUPERIOR...BUT AS
IT MOVES EAST ACROSS THE REST OF THE LAKE TODAY IT WILL SHIFT WINDS
TO THE WEST AND LEAD TO GALES TO 35 KNOTS FOR PORTIONS OF WESTERN
LAKE SUPERIOR THIS AFTERNOON AND EXPANDING ACROSS THE REST OF
THE WESTERN HALF OF THE LAKE TONIGHT AND CONTINUING INTO MONDAY.
WITH THE LOW SLOWLY WEAKENING MONDAY NIGHT INTO TUESDAY AS IT NEARS
JAMES BAY...THE WINDS WILL GRADUALLY DIMINISH AND TURN TO THE
NORTHWEST. HIGH PRESSURE WILL BUILD OVER THE UPPER GREAT LAKES
REGION FOR WEDNESDAY AND THURSDAY..WHICH WILL LOWER WINDS BELOW
20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 8 PM EDT /7 PM CDT/ MONDAY FOR LSZ162-263-264.
GALE WARNING FROM 2 AM TO 8 PM EDT MONDAY FOR LSZ265.
GALE WARNING FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO 5 PM EDT
/4 PM CDT/ MONDAY FOR LSZ240>244.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
142 PM EDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 134 PM EDT SUN AUG 23 2015
LINE OF THUNDERSTORMS IS MOVING ACROSS N LOWER ATTM, WITH THE
A MORE STRATIFORM PORTION IN E UPPER. NO CHANGES EXPECTED DURING
THE NEXT HOUR OR TWO IN THE FORECAST AS IT LOOKS LIKE THE STORM
TIMING IS ABOUT WHAT WE HAVE IN THE FORECAST.
UPDATE ISSUED AT 939 AM EDT SUN AUG 23 2015
COLD FRONT AND THUNDERSTORMS ASSOCIATED WITH THE FRONT IS MAKING
PROGRESS TO AND ACROSS LAKE MICHIGAN AT THE MOMENT. UPDATED THE
POPS TO SLOW THE TIMING DOWN JUST A BIT BASED ON THE RADAR TRENDS
AND THE HRRR WHICH SEEMED TO LINE UP PRETTY WELL AT 11Z WITH THE
CURRENT TRENDS. WILL CONTINUE TO UPDATE AGGRESSIVELY WITH THE
TIMING OVER THE NEXT FEW HOURS AS THE FRONT MOVES ACROSS THE
REGION. LATER HRRR RUNS SEEM TO GO ALONG AS WELL WITH THE CURRENT
RADAR TRENDS FROM KGRB AND KAPX. OTHERWISE, TEMPERATURES SEEM TO
BE FALLING ALONG WITH THE CURRENT THINKING.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 326 AM EDT SUN AUG 23 2015
HIGH IMPACT WEATHER: BAND OF SHOWERS AND STORMS. A FEW SEVERE
POSSIBLE.
SYNOPTIC PATTERN AND OBSERVATIONS:
EARLY MORNING ANALYSIS..A VERY IMPRESSIVE SHORTWAVE HAS CLOSED OFF
WHILE WORKING INTO MN. THE ASSOCIATED SFC LOW PRESSURE WAS FILLING
IN WESTERN ONTARIO...WITH A COLD FRONT DRAPED SOUTHWARD THROUGH NW
WISCONSIN AND IA. A BAND OF SHOWERS AND STORMS CONTINUES TO SLOWLY
PROGRESS EAST...WITHIN AXIS OF HIGH THETA-E AND SUPPORTED BY A SWATH
OF UPPER LEVEL DIVERGENCE IN A DOUBLE JET STRUCTURE. LAPSE RATES NOT
IMPRESSIVE...BUT DYNAMICAL FORCING IS ENOUGH TO CONTINUE STORMS INTO
THE NIGHT. ACROSS NRN MICHIGAN...AN EARLIER WING OF HIGHER THETA-E
AT 850MB HAS SLOWLY LIFTED NNE...WHILE A CORRIDOR OF DRIER/LOWER
THETA-E WAS WORKING INTO THE REGION. SKIES WERE CLEAR WITH ONLY SOME
THIN CIRRUS ENCROACHING. TEMPERATURES WERE IN THE 60S.
SYNOPTIC PATTERN EVOLUTION AND ASSOCIATED WEATHER:
QUITE A CHANGE IN THE WEATHER IS IN STORE. FIRST OFF...THE UPSTREAM
COLD FRONT WILL CROSS NRN MICHIGAN MID-LATE MORNING THROUGH EARLY
THIS EVENING. ONE VORTICITY MAX WILL LIFT NE INTO THE WESTERN CWA
THIS MORNING...AND ANOTHER THIS AFTERNOON...ROUNDING THE BASE OF THE
CLOSED/NEGATIVELY TILTED UPPER TROUGH. WE DO GET INTO SOME UPPER
DIVERGENCE WITH A LEFT FRONT EXIT REGION...OF A JET ON THE SRN
PERIPHERY OF THE UPPER TROUGH...BUT FORCING MAINLY APPLIED BY DPVA
AND LOW LEVEL CONVERGENCE. LAPSE RATES ARE LESS THAN DESIRABLE AT
5.5 TO 6.0 C/KM. SFC BASED DEW POINTS WILL ONLY BE IN THE MIDDLE 50S
WITHIN THE DRIER AIR/SWATH OF LOWER THETA-E AIR...BUT DEW POINTS
WILL POOL IN THE LOWER HALF OF THE 60S ALONG THE FRONT WHICH ARRIVES
MID-LATE MORNING ACROSS THE WESTERN CWA...AND THIS AFTERNOON ACROSS
NE LOWER. HEATING WILL BE DIFFICULT TO COME BY IN THE WESTERN
CWA...WITH CLOUDS INCREASING TOO EARLY FOR MUCH HEATING WHERE HIGHS
WILL BE IN THE LOWER 70S. ACROSS NE LOWER...SUNSHINE WILL BE ABLE TO
WARM TEMPERATURES INTO THE UPPER 70S AROUND 80F. BY THE TIME THE
FRONT ARRIVES WITH THE BETTER LOW LEVEL MOISTURE...CAPE WILL BE IN
THE 800-1200 J/KM RANGE. NOT OVERLAY FANTASTIC...AND 0-6 KM BULK
SHEAR WITH THE STORMS WILL BE MARGINAL FOR ANY ORGANIZED
CONVECTION...25-30KTS. ALL-IN-ALL...A FEW STORMS MAY BE ABLE TO
BECOME SEVERE...MAINLY M-32 SOUTH AND MOSTLY EAST OF I-75. DAMAGING
WINDS THE MAIN THREAT...BUT STRONGER CELLS WILL BE ABLE TO PRODUCE
AT LEAST SOME HAIL.
BEHIND THE FRONT...SOME SCATTERED SHOWERS ARE LIKELY...BUT DEEPER
MOISTURE STRIPS OUT WITH A POSSIBLE A PERIOD OF CLEARING. COOLER LOW
LEVEL AIR AND DEEPER LOWER LEVEL MOISTURE ADVECTION THROUGH THE
NIGHT. THE DEEPEST MOISTURE WILL REMAIN TO OUR NW...BUT WE HAVE
ENOUGH OVERNIGHT TO COMBINE WITH H8 TEMPS CRASHING INTO THE SINGLE
DIGITS FOR THE DEVELOPMENT OF LAKE EFFECT RAIN SHOWERS. NOT ONLY
THAT...BUT THE INSTABILITY DEEPENS OVER THE LAKES (500-700 J/KG) AND
THERE WILL BE AT LEAST A CHANCE FOR A RUMBLE OF THUNDER OR TWO. THIS
WILL PRIMARILY BE WSW FLOW REGIMES...ACROSS FAR NW LOWER...THROUGH
THE STRAITS...AND OVER TO DRUMMOND ISLAND.
HIGHS WILL RANGE FROM THE LOWER 70S WEST TO THE UPPER 70S EAST. LOWS
TONIGHT GENERALLY IN THE MIDDLE 50S AND GUSTY ALONG THE LAKE
MICHIGAN COAST.
&&
.SHORT TERM...(MONDAY THROUGH TUESDAY NIGHT)
ISSUED AT 326 AM EDT SUN AUG 23 2015
HIGH IMPACT WEATHER POTENTIAL: BESIDES JUST BEING DOWNRIGHT CHILLY
MONDAY AND TUESDAY...STILL MONITORING WATERSPOUT POTENTIAL FOR BOTH
THESE DAYS (WHICH WILL BE COVERED IN THE MARINE SECTION TO FOLLOW).
PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: PATTERN GETTING SET TO
BECOME QUITE THE AMPLIFIED ONE...WITH MAIN PLAYER DRIVING SUCH
AMPLIFICATION BEING STRONG UPPER JET CORE/ATTENDANT MID LEVEL WAVE
DIGGING INTO THE UPPER MISSISSIPPI VALLEY EARLY THIS MORNING. THIS
SYSTEM WILL HELP CARVE OUT AN ANOMALOUSLY DEEP (FOR THE TIME OF YEAR
AT LEAST) AND CHILLY MID LEVEL LOW...WHICH WILL CENTER ITSELF RIGHT
OVER THE NORTHERN LAKES AND SOUTHERN CANADA THROUGH AT LEAST THE
FIRST HALF OF THIS UPCOMING WORK WEEK.
PRIMARY FORECAST CONCERNS/CHALLENGES: ADDRESSING MULTIPLE PERIODS OF
LAKE ENHANCED SHOWERS. TEMPERATURE TRENDS THROUGH THE FORECAST.
ADDRESSING WATERSPOUT POTENTIAL.
DETAILS: UPPER LEVEL LOW...CHECK. COOL TEMPERATURES...CHECK. GUSTY
WINDS...CHECK. LAKE ENHANCED RAIN SHOWERS...CHECK. YUP...IT ALL ADDS
UP...OCTOBER WEATHER HERE IN THE END OF AUGUST. THAT`S MONDAY`S AND
TUESDAY`S WEATHER FOLKS...AND EVEN A COOL WEATHER FAN LIKE MYSELF
HAS TO SAY ITS NOT LOOKING PLEASANT. BLAME IT ALL ON THAT CURRENT
MINNESOTA WAVE...WITH IT AND A NICE UPPER LEVEL COUPLED JET HELPING
CARVE OUT THAT DEEP LOW MENTIONED EARLIER. DEEP CYCLONIC FLOW AROUND
IT...COUPLED WITH EXCELLENT LOW LEVEL MOISTURE AND PERIODS OF UPWARD
QG SUPPORT WILL BE MORE THAN ENOUGH TO KICK OFF SOME SHOWERS. ADD IN
INCREASING LAKE MOISTURE CONTRIBUTION AS H8 TEMPS FALL INTO THE MID
SINGLE DIGITS AND DIURNALLY DRIVEN ENHANCEMENT AWAY FROM THE
LAKES...AND NUMEROUS TO WIDESPREAD SHOWERS APPEARS A PRETTY GOOD
BET. DAYTIME FORECASTER TRENDED TOWARD THIS MORE WET LOOKING
SCENARIO...AND SIMPLY SEE NO REASON TO DEVIATE FROM IT. IT IS NOT
COMPLETELY OUT OF THE QUESTION FOR SOME LAKE PRODUCED THUNDERSTORMS
...PARTICULARLY MONDAY AND MONDAY EVENING WHEN NAM-WRF BUFKIT
SOUNDINGS SHOW IN EXCESS OF 500 J/KG OF LAKE INDUCED CAPE AND
EQUILIBRIUM LEVELS OVER 20 KFT. IF STORMS DO FORM...SOME SMALL HAIL
IS INDEED POSSIBLE WITH WET BULB ZERO HEIGHTS AT ONLY ABOUT 6KFT.
AS MENTIONED...IT`S GONNA BE DOWNRIGHT CHILLY FOR AUGUST...WITH
CLOUDS...SHOWERS...AND AN UNSEASONABLY COOL AIRMASS KEEPING HIGHS
MOSTLY IN THE 60S. AS HAS BEEN MENTIONED THE LAST FEW DAYS...COULD
EASILY SEE PARTS OF EASTERN UPPER AND THE HIGHLAND OF NORTHERN LOWER
FAILING TO BREAK 60 DEGREES...ESPECIALLY ON TUESDAY. IT REALLY WON`T
MATTER...WITH PRETTY GUSTY WINDS MAKING IT FEEL IN THE 50S ACROSS
MUCH OF THE AREA.
&&
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 326 AM EDT SUN AUG 23 2015
WHILE SLOWLY WANING...TROUGHING AND COOL WEATHER CONTINUE TO
DOMINATE HEADING RIGHT INTO WEDNESDAY. LAKE PROCESSES WILL
CONTINUE...ALTHOUGH SLOWLY WEAKENING WITH TIME AS COLD CORE
ANOMALIES RELAX AND FORCING DEPARTS. ANY BREAK LATER WEDNESDAY
NIGHT AND THURSDAY WILL BE SHORT- LIVED AS FAST MOVING WAVE DIVES
THROUGH NORTHWEST FLOW ALOFT...WITH IT AND ITS ATTENDANT COLD
FRONT RETURNING A SHOWER THREAT FRIDAY INTO THE START OF SATURDAY.
WHILE NOT NEAR AS COOL AS EARLIER IN THE WEEK... TEMPERATURES WILL
CONTINUE TO RUN AT LEAST A FEW DEGREES BELOW NORMAL.
MARINE...STILL CONCERNED ABOUT WATERSPOUT POTENTIAL...ESPECIALLY
LATER MONDAY INTO MONDAY NIGHT WHEN LAKE-INDUCED CAPE IS
MAXIMIZED...PERHAPS EXCEEDING 500 J/KG WITH EQUILIBRIUM LEVELS UP
NEAR 20KFT. WHILE THIS MAY BE A TOUCH AGGRESSIVE...WITH DEEP
TROUGHING AND SEVERAL WAVES/SURFACE TROUGHS TO ENHANCE
CONVERGENCE...GOTTA BELIEVE THERE IS SOME POTENTIAL. WILL NOT
INTRODUCE THIS WORDING TO THE OFFICIAL FORECAST JUST YET...USING THE
LATEST HAZARDOUS WEATHER OUTLOOK TO EXPRESS THIS CONCERN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN AUG 23 2015
MVFR TO POSSIBLE IFR NEAR THE THUNDERSTORMS. THE BACK EDGE OF THE
STORMS IS NEARING TVC AT THE MOMENT AND IS THROUGH MBL. WILL
EXPECT THAT THE STORMS WILL BE OF THE LAKE HURON SHORE BY 00Z.
AFTER THAT, SIGNIFICANT COOLING WILL TAKE PLACE, ESPECIALLY AT 850
MB. THE COOLING WILL LEAD TO RAIN SHOWERS LATER TONIGHT. AS THE
COLDER AIR SPREADS MORE INTO NORTHERN MICHIGAN, THE RAIN SHOWERS
WILL CONTINUE TO SPREAD OUT OVER NW LOWER MICHIGAN. WITH THE RAIN
SHOWERS IT LOOKS LIKE MVFR CIGS, AND OCCASIONAL MVFR VSBYS.
&&
.MARINE...
ISSUED AT 326 AM EDT SUN AUG 23 2015
SOUTHERLY WINDS ARE INCREASING ACROSS THE LAKES AHEAD OF AN
APPROACHING COLD FRONT...WHICH WILL CROSS THE REGION TODAY AND THIS
EVENING. ADVISORY LEVEL GUSTS ARE EXPECTED AT ALL NEARSHORES...BUT
AS WE REMAIN IN A TIGHT GRADIENT BEHIND THE FRONT...IN STRONG COLD
ADVECTION...ADVISORY LEVEL GUSTS ARE A BETTER BET. THE FRONT WILL
BRING A BAND OF SHOWERS AND STORMS...SOME OF WHICH MAY BE STRONG
WITH SOME GUSTY WINDS AND HAIL. STRONG COLD ADVECTION CONTINUES INTO
MONDAY WITH LAKE EFFECT RAIN SHOWERS (AND A FEW RUMBLES OF THUNDER
AGAIN POSSIBLE). OTHER ISSUES COME ABOUT...LIKE THE NEED TO MONITOR
FOR POSSIBLE WATERSPOUTS...ESPECIALLY LATER MONDAY THROUGH TUESDAY.
SIMPLE PATTERN RECOGNITION OF ANOMALOUSLY DEEP MID AND UPPER LEVEL
LOW CENTERED NEARBY THIS TIME OF YEAR SURE SUPPORTS SUCH. EARLY
INDICATIONS OF SEVERAL VORT LOBES/ATTENDANT SURFACE TROUGHS ROTATING
AROUND PARENT CIRCULATION...FURTHER ENHANCING LOW LEVEL CONVERGENCE.
LAKE INDUCED EQUILIBRIUM LEVELS SOARING TO OVER 20 KFT DURING THIS
PERIOD...WHICH FAVORS UPPER LEVEL LOW ASSOCIATED WATERSPOUTS PER THE
SZILAGYI WATERSPOUT NOMOGRAM. WILL STILL NOT SPECIFICALLY INTRODUCE
THIS POTENTIAL IN THE FORECAST...BUT VERY WELL MAY NEED TO IN LATER
FORECASTS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ008-015-016-
019>021-025-031.
LH...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LSZ321-322.
&&
$$
UPDATE...JSL
NEAR TERM...SMD
SHORT TERM...MSB
LONG TERM...MSB
AVIATION...JSL
MARINE...SMD
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1239 PM CDT SUN AUG 23 2015
.UPDATE...
ISSUED AT 1228 PM CDT SUN AUG 23 2015
ANOTHER UPDATE FOR POPS/QPF/TEMPS TO MATCH TRENDS. HELD ONTO CLOUD
COVER IN THE SOUTH AND WEST A BIT LONGER WITH THIS UPDATE AS WELL. A
FEW AUTOMATED GAUGES WERE REPORTING MORE THAN FOUR TENTHS OF AN INCH
OF RAIN THIS MORNING AS THE SHOWERS MOVED THROUGH...SO NUDGED QPF
HIGHER. ALSO PUSHED THE HIGHER POPS A LITTLE FARTHER EASTWARD
THROUGH THIS AFTERNOON.
UPDATE ISSUED AT 918 AM CDT SUN AUG 23 2015
MINOR UPDATE TO INCREASE POPS/QPF AND ADJUST HOURLY AND MAX TEMPS
DOWN SLIGHTLY TO BETTER MATCH TRENDS. AREA OF SHOWERS HAS EXPANDED
OVER MN ZONES IN THE PAST FEW HOURS...SO HAVE INCREASED POPS OVER
THOSE AREAS. THINK SCATTERED VERY LIGHT SHOWERS WILL AFFECT NW WI
TOO...SO NUDGED POPS UP THERE AS WELL. TOOK QPF A LITTLE HIGHER...
ESPECIALLY THROUGH 18Z TO BETTER ACCOUNT FOR RADAR TRENDS. TEMPS
WERE NOT RECOVERING AS QUICKLY AS GOING FORECAST SUGGESTED...SO
TAMPED TEMPS DOWN AND CLOSER TO HRRR GUIDANCE.
UPDATE ISSUED AT 638 AM CDT SUN AUG 23 2015
UPDATED FOR THE NEW 12Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT SUN AUG 23 2015
THE STRONG SURFACE LOW OVER NORTHWEST ONTARIO WITH A COLD FRONT
EXTENDING SOUTH ACROSS THE FORECAST AREA AND DOWN INTO WESTERN
WISCONSIN AND INTO IOWA. A TROUGH AXIS ALSO EXTENDS DOWN INTO THE
RED RIVER VALLEY TO EASTERN SOUTH DAKOTA. ABOVE THIS...A TROWAL
EXTENDS INTO NORTHERN MINNESOTA WITH AN AREA OF SHOWERS AND SOME
THUNDERSTORMS. THE ASSOCIATED UPPER LOW IS OVER NORTHERN MINNESOTA.
THIS WHOLE SYSTEM WILL MOVE SLOWLY NORTHEAST TODAY AND
TONIGHT...BECOMING MORE STACKED WITH TIME AND MORE CUT OFF AT UPPER
LEVELS. THIS IS GOING TO LEAVE US WITH CYCLONIC FLOW AND PLENTY OF
SHOWERS AND CLOUD COVER. THE TROWAL IS GOING TO ROTATE ACROSS THE
NORTHERN FORECAST AREA TODAY...AND EVEN THIS EVENING BEFORE
WEAKENING OVERNIGHT. HAVE KEPT POPS HIGHEST ALONG THE NORTHERN
BORDER CLOSEST TO THE SURFACE LOW AND UNDER THE TROWAL...BUT TAPER
OFF TO DRY OR SLIGHT CHANCE TO THE SOUTH. THIS IS ALSO GOING TO
KEEP TEMPERATURES VERY COOL...WITH HIGHS ONLY IN THE UPPER 50S NORTH
TO LOW 60S SOUTH. THEN...TONIGHT THE CLOUD COVER IS GOING TO PULL
EAST SOME...AND ALONG WITH THE STRONG COLD AIR ADVECTION ALLOW
TEMPERATURES TO DROP INTO THE 40S OVERNIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 347 AM CDT SUN AUG 23 2015
A DEEP AREA OF LOW PRESSURE NORTH OF LAKE SUPERIOR WILL GRADUALLY
SHIFT INTO FAR NE ONTARIO FROM MONDAY MORNING THROUGH TUESDAY...THEN
HEAD INTO WESTERN QUEBEC ON WEDNESDAY. THIS LOW WILL CONTINUE TO
BRING THE NORTHLAND A PROLONGED PERIOD OF COOL AND BREEZY NORTHERLY
FLOW FOR THE EARLY PART OF THE WEEK...BUT WITH A TRANSITION TO SUNNY
AND SEASONABLY WARM WEATHER BY WEDNESDAY WHEN HIGH PRESSURE MOVES
INTO THE REGION. THIS WILL BRING A GRADUAL DAILY WARMING TREND INTO
THE MIDDLE OF THE WEEK...WITH HIGHS OF 10 TO 15 DEGREES BELOW NORMAL
ON MONDAY BECOMING NEAR NORMAL BY WEDNESDAY.
ISOLATED TO SCATTERED RAIN SHOWERS ARE EXPECTED OVER THE NORTHERN
AND EASTERN FORECAST AREA FOR MONDAY DUE TO THE DAYTIME HEATING AND
RESULTING LOW LEVEL LAPSE RATES. SHOWERS ARE ALSO POSSIBLE
TUESDAY...BUT MAINLY OVER THE ARROWHEAD.
SOUTHERLY RETURN FLOW WILL DEVELOP THURSDAY...CONTINUING THE WARMING
TREND. SUNNY SKIES AND THE SOUTHERLY BREEZE SHOULD ALLOW HIGHS TO
REACH SLIGHTLY ABOVE NORMAL. A SHORTWAVE TROUGH PASSAGE COULD BRING
SHOWERS AND STORMS LATE THURSDAY INTO FRIDAY.
THE MODELS ARE LACKING AGREEMENT FOR THE END OF THE WEEK. THE GFS
HAS A WARM FRONT NEAR THE SOUTHERN FORECAST AREA AND ASSOCIATED PCPN
FOR FRIDAY NIGHT AND SATURDAY...WHILE THE ECMWF HAS SURFACE HIGH
PRESSURE OVER MINNESOTA AND WISCONSIN WITH MOSTLY DRY WEATHER FOR
THE NORTHLAND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1228 PM CDT SUN AUG 23 2015
WIDESPREAD MVFR CIGS ACROSS THE REGION TODAY WITH A STRONG PUSH OF
COLD AIR FROM THE NORTH KEEPING A LAYER OF STRATO-CU AROUND
THROUGH AT LEAST THE NEXT 24 HOURS. COULD SEE A FEW SHOWERS MIXED
IN AT TIMES...ESPECIALLY FROM INL TO HIB TO HYR. GUSTY WEST/NW
WINDS WILL PERSIST THROUGH THE PERIOD AS WELL WITH NOT MUCH RELIEF
THROUGH THE OVERNIGHT HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 59 48 58 48 / 100 60 20 20
INL 57 43 56 45 / 100 70 30 0
BRD 61 49 66 48 / 60 20 0 0
HYR 61 48 60 47 / 80 30 10 0
ASX 64 48 59 51 / 100 40 20 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CDT MONDAY FOR LSZ121-140>148.
&&
$$
UPDATE...HUYCK
SHORT TERM...LE
LONG TERM...GROCHOCINSKI
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
331 PM CDT SUN AUG 23 2015
.DISCUSSION...
FRONTAL BOUNDARY IS CURRENTLY LOCATED OVER THE MO BOOTHEEL. THIS
FEATURE IS MOVING OUR WAY AND THERE MAY BE JUST ENOUGH INSTABILITY
IN PLACE TO ALLOW FOR REDEVELOPMENT OF SOME CONVECTIVE ACTIVITY
LATE THIS AFTERNOON AND INTO THIS EVENING...BEST CHANCE ALONG THE
PLATEAU. HRRR AND MODEL DATA BOTH CONCUR THAT SOME REDEVELOPMENT
IS POSSIBLE. STORMS SHOULD REMAIN BELOW STRONG LIMITS HOWEVER.
LATE TONIGHT...DRIER AIR WILL BEGIN WORKING IN. ENOUGH LOW LEVEL
MOISTURE MAY REMAIN SO AS TO PRODUCE SOME PATCHY FOG LATE ACROSS THE
PLATEAU AND SOUTH.
GOING FORWARD...SFC HIGH WILL BUILD IN AND BRING WITH IT A DRY
AIRMASS WITH BELOW NORMAL TEMPS. THERMAL TROUGHING WILL BE IN PLACE
WITH 850 MB TEMPS HOLDING GENERALLY IN THE 11C-14C RANGE. SO...WE
WILL SEE LOW TEMPERATURES IN THE 50S FOR MON NT AND TUES NT WITH
HIGHS IN THE LOWER 80S WEST OF PLATEAU. HUMIDITY LEVELS WILL BE LOW
WITH DEWPOINTS IN THE LOWER TO MID 50S.
IN THE EXT FCST...THERMAL TROUGH WILL REMAIN IN PLACE THROUGH
THURSDAY. SOUTHERLY RETURN FLOW NOT EXPECTED BEFORE FRIDAY SO WE
WILL SEE A CONTINUATION OF DRY CONDITIONS AND BELOW NORMAL TEMPS. A
WARMING TREND WILL COMMENCE BY SATURDAY AND SUNDAY AS UPPER RIDGING
BEGINS TO RETURN WITH THE THERMAL TROUGHING LIFTING OUT. HIGH TEMPS
BY SUNDAY WILL REACH BACK UP TOWARD THE UPPER 80S...WEST OF PLATEAU.
WILL OPT TO INCLUDE LOW POPS FOR SUNDAY AS JUST ENOUGH RETURN
MOISTURE LENDS A HAND TOWARD INCREASING OUR CAPE/CAP RATIOS.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 68 84 57 80 / 20 0 0 0
CLARKSVILLE 62 82 54 80 / 20 0 0 0
CROSSVILLE 66 79 53 77 / 30 10 0 0
COLUMBIA 67 84 56 81 / 20 0 0 0
LAWRENCEBURG 68 83 58 80 / 20 0 0 0
WAVERLY 63 83 55 80 / 20 0 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
236 PM CDT SUN AUG 23 2015
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
FOR THE REST OF THE AFTERNOON...MAY SEE A STRAY ISOLATED SHOWER OR
THUNDERSTORM IN LAVACA AND/OR DEWITT COUNTIES THIS AFTERNOON.
AMPLE INSTABILITY AND MOISTURE ARE PRESENT IN THE COASTAL PLAINS
FOR ISOLATED HEAVY THUNDERSTORMS BUT ARE LACKING MUCH OTHER THAN
HEATING TO GET PARCELS OFF THE SURFACE. NOT MUCH CAPPING IS
CURRENTLY PRESENT BUT LOW TO MID LEVEL WARMING WAS ADVERTISED IN
THE RAP SOUNDINGS SO THIS SHOULD STAY ISOLATED. ONLY MENTIONED
SOME ISO THUNDER WITH SUB 20 PERCENT POPS IN THIS VICINITY AS A
RESULT.
ISOLATED ACTIVITY IN MEXICO AND IN THE BIG BEND AREA SHOULD STAY
AWAY FROM THE CWA THIS AFTERNOON/EVENING. THE FRONTAL SYSTEM
RESPONSIBLE IS PROGGED TO BEGIN KNOCKING ON THE DOORSTEP MONDAY
MORNING AND SHOULD RESULT IN SOME CLOUD COVER AND SLIGHT CHANCE
POPS FOR THE NORTHERN THIRD OF THE AREA MONDAY. NOTHING HAZARDOUS
IS EXPECTED THOUGH.
&&
.LONG TERM (TUESDAY THROUGH SUNDAY)...
THE FOCUS OF THE LONG TERM IS ON THE PROSPECT FOR CHC POPS
TUESDAY. A COLD FRONT WILL PUSH SOUTHWARD ACROSS THE MS RIVER
VALLEY AND PROVIDE A SIMILAR PATTERN TO A FEW THIS SUMMER THAT
HAVE RESULTED IN APPRECIABLE RAINFALL FOR THE CWA. AS THE COLD
FRONT PROGRESSES WESTWARD INTO EAST TEXAS...MODELS ARE SHOWING
VARYING AMOUNTS OF QPF GENERATION...MOSTLY DUE TO DISAGREEMENT IN
AVAILABLE MOISTURE AND FRONTAL STRENGTH. THE MOST BULLISH MODEL AS
FAR AS QPF GENERATION GOES IS THE ECMWF AS IT CAPTURES REMNANT
MOISTURE UNDER THE RIDGE DUE TO THE FRONTAL SYSTEM CURRENTLY IN
PLACE. THE GFS DOES NOT PRESCRIBE TO THIS AT ALL AND THE NAM
GIVES AN EASTERN PREFERENCE WHERE MOISTURE IS MORE PLENTIFUL. HAVE
FAVORED THE NAM DEPICTION THIS PACKAGE AND WPC QPF SEEMS TO AGREE.
THEREFORE OPTED FOR THE CHC POPS TO MOSTLY ALONG AND EAST OF THE
I35 CORRIDOR AND NORTH OF THE I10 CORRIDOR. MAY NEED SOME
ADJUSTING FARTHER SOUTH OF THE COLD FRONT CAN PUSH A BIT FARTHER
SOUTH...WHICH IS POSSIBLE GIVEN PREVIOUS SYSTEMS WE HAVE SEEN SO
FAR.
BEYOND THE TUESDAY TIME FRAME...UPPER LEVEL RIDGE PATTERN IS IN
AGREEMENT IN BOTH EURO AND GFS MODELS. GFS ENSEMBLES SHOW
IMPRESSIVE AGREEMENT FROM PERTURBATION TO PERTURBATION AS WELL FOR
OVER 100 HOURS OUT. CONTINUE TO BE SKEPTICAL OF EURO ADVERTISEMENT
OF QPF STRETCHING FROM THE GULF INTO THE CWA THROUGH WEDNESDAY.
AN EAGLE EYE WILL ENSUE ON THE ECMWF ENTERING THE WEEK FOR
POSSIBLE WEDNESDAY CHANGES TO THE POP FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 76 99 77 100 75 / - 20 - 30 10
AUSTIN BERGSTROM INTL AIRPORT 74 99 75 99 73 / - 20 - 30 10
NEW BRAUNFELS MUNI AIRPORT 76 100 75 100 74 / - - - 20 -
BURNET MUNI AIRPORT 76 97 75 98 73 / - 20 10 30 10
DEL RIO INTL AIRPORT 77 100 77 101 76 / - - 0 10 0
GEORGETOWN MUNI AIRPORT 76 99 76 99 74 / - 20 10 30 10
HONDO MUNI AIRPORT 73 99 74 99 73 / - - 0 10 -
SAN MARCOS MUNI AIRPORT 76 99 76 99 74 / - - - 30 10
LA GRANGE - FAYETTE REGIONAL 77 99 76 99 74 / - - 10 30 10
SAN ANTONIO INTL AIRPORT 78 99 77 99 76 / - - - 20 -
STINSON MUNI AIRPORT 76 100 76 100 76 / - - 0 20 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...RUNYEN
SYNOPTIC/GRIDS...TB3
PUBLIC SERVICE/DATA COLLECTION...TREADWAY
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
102 PM CDT SUN AUG 23 2015
.AVIATION...
ISOLATED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS THE SOUTH
PLAINS OVER THE PAST HOUR WITH ACTIVITY EXPECTED TO CONTINUE IN
THE VICINITY OF KPVW AND KLBB THROUGH THE LATE AFTERNOON. MVFR
CIGS ARE EXPECTED TO ERODE BY MID AFTERNOON AT KPVW AND
KCDS...WIND GUSTS UP TO 25-30 MPH CAN BE EXPECTED WITH ANY
THUNDERSTORMS...WITH SUSTAINED WINDS OUT OF THE NORTHEAST AROUND
15 MPH AT ALL TERMINALS INTO THE EVENING.
&&
.PREV DISCUSSION... /ISSUED 1209 PM CDT SUN AUG 23 2015/
UPDATE...
A FEW SHOWERS AND T-STORMS ARE DEVELOPING ACROSS THE CENTRAL AND
EASTERN SOUTH PLAINS TO THE NORTH OF THE COLD FRONT WHICH IS JUST
EXITING OUR SRN ZONES. WE HAVE ADDED AN ISOLATED MENTION TO THE
FORECAST THROUGH THE AFTERNOON FOR ROUGHLY THE SRN 2/3RDS OF THE
FORECAST AREA. SOME BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE
UNDERNEATH THESE CELLS.
PREV DISCUSSION... /ISSUED 402 AM CDT SUN AUG 23 2015/
SHORT TERM...
CANADIAN FRONT AT 4 AM WAS MAKING STEADY PROGRESS SOUTH ACROSS THE
SOUTHERN PANHANDLE AND AT ITS PRESENT MOTION OF 25-30 MPH SHOULD
BE IN LUBBOCK BY SUNRISE. STRONGEST PRESSURE RISES WERE FOCUSING
ACROSS THE WESTERN PANHANDLE WHERE EARLIER DALHART OBSERVED LOWER
VISBYS AND BLOWING DUST FROM NORTHERLY GUSTS OVER 30 MPH. ASIDE
FROM A FEW SCANT SHOWERS AND STORMS IN THE ENHANCED POST-FRONTAL
UPSLOPE REGIME OF NERN NM...PRECIP CHANCES ARE SHAPING UP QUITE
POOR GIVEN AN OVERALL ABSENCE OF PRE AND POST-FRONTAL CLOUDS.
WORSE...REGIONAL VWP DATA SHOW THAT THE LLJ HAS VEERED SW /NOW
PARALLEL TO THE FRONT/ WHICH IS FURTHER HURTING OPPORTUNITIES FOR
DEEPER CONVERGENCE AND SATURATED ASCENT. IN LIGHT OF THESE
UNFAVORABLE FACTORS...EARLIER CHANCE POPS WERE SHOWN THE DOOR. AN
ERRANT SHOWER MAY STILL SNEAK INTO OUR NW ZONES FROM THE MORE
FAVORABLE NELY UPSLOPE FLOW IN ERN NM...BUT ODDS ARE LOOKING
QUITE LONG FOR MEASURABLE PRECIP THIS A.M.
THE FRONT IS LIKELY TO STALL IN THE PERMIAN BASIN THIS AFTERNOON
AS THE SURFACE HIGH HOLDS UP IN THE NRN PANHANDLE. ALTHOUGH NELY
WINDS WILL ADVECT AN AXIS OF RICH POST-FRONTAL DEWPOINTS INTO OUR
SERN COUNTIES FROM OKLAHOMA...MOST MODEL SOUNDINGS NORTH OF THE
FRONT SHOW TOO MUCH CINH EVEN WITH WARMER TEMPS FROM A REDUCED
COVERAGE OF CLOUDS. DID RETAIN A SLIVER OF LOW POPS IN OUR
SOUTHERN ROW OF COUNTIES GIVEN THEIR PROXIMITY TO THE BOUNDARY...
BUT EVEN THIS MAY BE TOO OPTIMISTIC. TONIGHT...SOME MODELS ARE
EAGER TO CONVECT IN A SHALLOW AND WEAK ISENTROPIC REGIME...THOUGH
THIS POSSIBILITY SEEMS OVERDONE GIVEN NO BACKGROUND ASSISTANCE AND
AN EASTERLY LLJ TAKING AIM WELL TO OUR SW ALONG THE UPPER TRANS
PECOS. A LINGERING SWATH OF MID-LEVEL MOISTURE EVIDENT ON WATER
VAPOR ACROSS SRN NM SEEMS A MORE LIKELY LOCATION FOR POPS IN THE
NEXT 24 HOURS...SO POPS TONIGHT WERE REMOVED OVER ALL BUT OUR FAR
SW COUNTIES. ASIDE FROM NUDGING HIGH TEMPS UPWARD TODAY...NO MAJOR
CHANGES TO TEMPS WERE NECESSARY.
LONG TERM...
CONCERNS ABOUT PRECIPITATION CHANCES CONTINUE INTO THE DAY MONDAY
AS THE STALLED BOUNDARY STARTS TO MOVE NORTHWARD AS A WARM FRONT
THROUGH THE DAY. AGAIN THERE IS A LACK OF ANY KIND OF SYNOPTIC
SCALE FORCING TO AID IN LIFTING PARCELS THROUGH THE DAY. AS THE
WARM FRONT MOVES ACROSS THE AREA...MODELS DO INCREASE MID-LEVEL
MOISTURE SOME RESULTING IN AT LEAST A BIT OF ELEVATED INSTABILITY
LATE IN THE AFTERNOON. WITH THE FRONT MOVING NORTHWARD THROUGH THE
DAY...ANY LOW-LEVEL FOCUS FOR STORM DEVELOPMENT WILL GRADUALLY
SHIFT NORTH AND EASTWARD AND HAVE DROPPED POPS AND ADJUSTED THEM
TO FAVOR THE ROLLING PLAINS BY MONDAY EVENING WHERE DEEPER
MOISTURE WILL RESIDE. THE NAM ALSO HOLDS THE FRONT UP ACROSS THE
ROLLING PLAINS INTO TUESDAY MORNING WITH WEAK PRESSURE RISES BUT
CONDITIONS WILL CONTINUE TO BECOME LESS AND LESS FAVORABLE THROUGH
THE DAY AS THE RIDGE BUILDS BACK EASTWARD AND AS A STRENGTHENING
UPPER- LEVEL JET DEVELOPS EAST OF THE FORECAST AREA INCREASING
SUBSIDENCE ALOFT AT THE SAME TIME.
FORECAST FOR THE MIDDLE PART OF THE WEEK IS SEASONABLY HOT AND DRY
WITH THE RIDGE GRADUALLY BUILDING IN ALOFT...WITH HEIGHTS AT THEIR
GREATEST ON TUESDAY AND WEDNESDAY. A SLIGHT SHIFT IN THE RIDGE TO
THE WEST IS STILL EXPECTED FOR THE END OF THE WEEK WHICH WILL
PLACE US IN NORTHWEST FLOW ALOFT. THERE ARE STILL INDICATIONS OF
A COUPLE OF SHORTWAVES MOVING SOUTHEAST ACROSS THE REGION FOR
THURSDAY NIGHT AND FRIDAY NIGHT WHICH COULD BRING A RETURN OF
SLIGHT CHANCE POPS BOTH THOSE DAYS ALONG WITH SLIGHTLY COOLER HIGH
TEMPERATURES. THE PROSPECTS FOR ANOTHER COOL FRONT FOR THE END OF
THE WEEK DO NOT LOOK QUITE AS GOOD AS THE GFS HAS BACKED OFF ON
THIS POSSIBILITY WHILE THE ECMWF HINTS AT A VERY WEAK BOUNDARY
ARRIVING SATURDAY.
JORDAN
LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
$$
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 58 86 62 91 / 10 20 10 10
TULIA 60 85 63 90 / 10 20 20 20
PLAINVIEW 60 85 64 91 / 10 20 10 20
LEVELLAND 63 86 65 91 / 10 20 10 10
LUBBOCK 63 87 66 92 / 10 20 10 20
DENVER CITY 65 87 65 91 / 20 20 10 10
BROWNFIELD 65 87 67 91 / 10 20 10 10
CHILDRESS 67 87 67 93 / 10 20 20 20
SPUR 67 88 67 94 / 10 20 20 20
ASPERMONT 71 92 71 96 / 10 20 20 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
Area Forecast Discussion
National Weather Service Midland/Odessa TX
1255 PM CDT SUN AUG 23 2015
.DISCUSSION...
Please see the 23/18Z forecast discussion below.
&&
.AVIATION...
VFR conditions will for the most part prevail across all area
terminals through 24/18Z. A quasi-stationary cold front
(presently extending from about 20 S KGDP - KINK - Lamesa) will
serve as the focus for scattered TSRA this afternoon, with
coverage extending into the evening as moist upglide commences
above this front after sunset. As such, have gone pessimistic at
KCNM, KHOB, and KINK where TEMPOs are warranted. MVFR visibility in
TSRA and wind gusts to 40 kts are possible at these locales.
Storms are firing over the Davis Mountains and may eventually
impact KFST during the late afternoon hours, with similar MVFR
visibility and wind gusts to 40 kts (maybe more here, depending on
how much heating occurs over the Pecos River valley). At this time
we don`t see a strong enough signal at KPEQ to introduce TEMPO
TSRA here, but will monitor. Less of a chance at KMAF, although a
few of the past HRRR runs indicate some spotty -SHRA/TSRA in the
late afternoon/evening hours over the Permian Basin. Bears watch.
Conditions will gradually improve around midnight local time, with
a lot of convective debris overhead. There are indications that
moist upslope on the east side of the Guadalupes/Delawares will
produce MVFR to IFR conditions toward daybreak Monday. Have kept
VFR conditions at KCNM and KPEQ and will await further data.
&&
.PREV DISCUSSION... /issued 626 AM CDT SUN AUG 23 2015/
DISCUSSION...
See 12z aviation discussion below.
AVIATION...
VFR conditions are expected for the next 24 hours. Showers and
thunderstorms are possible this afternoon across the area
especially for CNM and HOB. Light and variable winds will come
around to the north beginning this morning as a cold front moves
into the area around 15z. The strongest winds appear to be at CNM
and winds are expected to shift to the east this afternoon. Winds
will likely be variable with some gusts.
PREV DISCUSSION... /issued 415 AM CDT SUN AUG 23 2015/
DISCUSSION...
WV imagery shows an upper-lvl ridge extending across the srn CONUS,
from SoCal to the Florida. To the north, a trough was ejecting into
nrn MN. Closer to home, sfc obs and area radars show a cold front
moving thru the Texas Panhandle, trailing the trough. This feature
looks much weaker/shallower than last week`s front, w/only modest
pressure rises along the front. Models differ somewhat on how far
it makes it into the FA, w/the NAM bringing it into mid-CWA, whereas
the GFS and ECMWF stall it a little further north. Going w/the NAM,
it looks as though the front will stall diurnally this afternoon,
before retreating north just a little overnight as a 25-30kt LLJ
develops. This will be the main focus for convection, w/best chances
over SE NM along the front this afternoon. If the GFS pans out, SE
NM could see significant rainfall.
Otherwise, thicknesses should bottom out Monday, but temps will
remain above-normal Monday afternoon before the ridge intensifies
over the SW CONUS later in the week, pushing temps once more into
the upper 90s most locations. Unfortunately, models keep the theta-
e ridge to the west, affording little chances of rain in the
extended.
MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
$$
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
70
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
218 PM EDT SUN AUG 23 2015
.SYNOPSIS...
HIGH PRESSURE HEADS EAST TODAY WITH A COLD FRONT PRESSING INTO THE
OHIO AND TENNESSEE VALLEYS. THE FRONT MOVES ACROSS US
MONDAY...WITH A LARGE HIGH SHIFTING OVER THE NORTHERN PLAINS. THIS
HIGH WILL GIVE US LOWER HUMIDITIES FOR MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM EDT SUNDAY...
FOR TODAY...WE WILL SEE THE WESTERN FORECAST AREA REMAIN IN THE
HIGHER THETA-E AIR AHEAD OF A STRONGER SHORTWAVE OVER WESTERN TENN
THIS MORNING. THIS WAVE IS EXPECTED TO SHIFT EAST INTO THE SMOKYS/GA
AREA BY MID AFTERNOON. SW FLOW AHEAD OF IT WILL AID IN MOISTURE
ADVECTION. CLOUD COVER WILL BE PROBLEMATIC IN TERMS OF CONVECTION
BUT THINK WILL BE ENOUGH SUNSHINE TO ALLOW CONVECTIVE TEMPS TO BE
EXCEEDED...WITH THUNDERSTORMS A GOOD BET OVER THE NORTH CAROLINA
MOUNTAINS AND FOOTHILLS NW INTO SW VA/SRN WV BY LATE AFTERNOON.
WITH THE 10 AM UPDATE...DECREASED RAIN CHANCES FOR THE MORNING
ACROSS THE MOUNTAINS...WITH RAIN CHANCES INCREASING DURING THE
AFTERNOON. RAINFALL WILL BE MAINLY SHOWER ACTIVITY...BUT WITH A
FEW THUNDERSTORMS DEVELOPING AS WE APPROACH MAX AFTERNOON HEATING.
FOLLOWED A COMBINATION OF THE LOCAL WRF AND HRRR WEATHER FORECAST
MODELS...WHICH DEPICTS BEST LIFT AND CONCENTRATION OF SHOWERS AND
STORMS OVER THE MOUNTAINS SOUTH OF HIGHWAY 460...THEN START TO
BLEND IN THE 0Z GFS/NAM AFTER MID AFTERNOON. BELIEVE THE PIEDMONT
AREA EAST OF LYNCHBURG AND DANVILLE WILL SEE LITTLE TO NONE AS
AXIS OF SFC RIDGE KEEPS THINGS SUPPRESSED.
FOR HIGHS TODAY...MADE ONLY MINOR CHANGES TO THE TEMPERATURE
FORECAST BASED ON CLOUD COVER. EXPECT SEASONAL TEMPS FROM THE MID
TO UPPER 70S HIGHER TERRAIN OF NC TO LOWER 80S OVER MOST OF THE
WESTERN CWA...WITH MID TO UPPER 80S FROM ROANOKE EAST.
TONIGHT...THE UPPER WAVE PIVOTS EAST AND WE SHOULD SEE THINGS DRY
OUT. MAY STILL ALLOW FOR A FEW SHOWERS ALONG THE BLUE RIDGE LATE
EVENING. NEXT THREAT WILL BE MAINLY AFTER THIS PERIOD WITH THE COLD
FRONT MONDAY...SO HAVE SLIGHT CHANCE POPS INTO THE WV MOUNTAIN
AROUND DAWN MONDAY. SOME DIFFERENCES IN CLOUD COVER TONIGHT...BUT
OVERALL SHOULD BE CLEARING FOR MOST WITH CLOUDS INCREASING AGAIN
LATE IN THE WEST. LOWS WITH HUMIDITY STAYING UP WILL BE IN THE 60S.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 315 AM EDT SUNDAY...
THE UPPER PATTERN WILL BE FIRMLY ESTABLISHED IN AN AMPLIFIED EASTERN
TROF/WESTERN RIDGE WITH A CLOSED LOW MEANDERING THROUGH THE GREAT LAKES
REGION. THIS WILL KEEP THE HEAT LOCKED UP OUT WEST AND GIVE US SOME
PLEASANT LATE SUMMER WEATHER FOR THE MIDDLE OF THE WEEK. HOWEVER...TO
GET TO THIS PLEASANT WEATHER WE HAVE TO GET ON THE OTHER SIDE OF A COLD
FRONT BEING DRAGGED THROUGH THE REGION ON MONDAY BY A LARGE SURFACE LOW
OVER SOUTHERN CANADA.
THE FRONT WILL ARRIVE IN THE WEST A BIT TO EARLY TO ACCESS SIGNIFICANT
DIURNAL INSTABILITY...BUT AREAS EAST OF THE BLUE RIDGE WILL BE ABLE TO
HEAT UP CONSIDERABLY RIGHT AHEAD OF THE FRONT. THUS...EXPECT THE FRONT
WILL ENTER FROM THE WEST IN THE MORNING THEN JUMP TO THE LEE TROF EAST
OF THE BLUE RIDGE FOR THE AFTERNOON AND KEEP MOST OF THE CONVECTIVE
ACTIVITY ACROSS THE PIEDMONT. WILL INDICATE THIS IN THE GRIDS WITH
HIGHEST POPS EAST AND SOMEWHAT LOWER POPS THROUGH THE MIDDLE. THE
SEVERE THREAT IS LOW AS SUPPORTING SYNOPTIC DYNAMICS ARE LARGELY ABSENT
BUT THE AIRMASS WILL BE QUITE JUICY AHEAD OF THE FRONT SO LOCALLY HEAVY
RAIN WILL BE A POSSIBILITY. THE FRONT LOOKS TO PUSH OFF TO THE EAST
MONDAY EVENING FOLLOWED BY A LARGE HIGH PRESSURE SYSTEM BUILDING IN
FROM THE NORTHERN PLAINS.
TEMPERATURES ON MONDAY WILL WARM INTO THE LOWER 90S ACROSS THE PIEDMONT
AHEAD OF THE FRONT...BUT TO THE WEST READINGS WILL BE TEMPERED BY THE
EARLY ARRIVAL OF THE FRONT AND WILL PEAK IN THE UPPER 70S/AROUND 80.
HIGHS TUESDAY AND WEDNESDAY WILL BE SEASONABLE TO SLIGHTLY BELOW NORMAL
WITH LOW HUMIDITY. EXPECT LOW/MID 80S EAST AND GENERALLY MIDDLE 70S
WEST. THE COOLNESS BEHIND THE FRONT WILL REALLY BE FELT IN LOW
TEMPERATURES WITH READINGS NEAR 60 EAST TO LOWER 50S WEST AND SOME 40S
IN THE VALLEYS MAKING FOR DEPARTURES OF 5F TO 10F BELOW NORMAL.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 220 PM EDT SATURDAY...
AN UPPER LEVEL TROUGH WILL KEEP THE REGION RELATIVELY COOL AND DRY
THROUGH THE REST OF THE WEEK. THE TROUGH AXIS WILL REMAIN OVER THE
OHIO-TENN VALLEY WEDNESDAY...THEN PIVOT OVER THE APPALACHIANS ON
THURSDAY. IF ENOUGH MOISTURE IS AVAILABLE...A FEW MOUNTAIN SHOWERS
MAY DEVELOP THURSDAY AND MORE SCATTERED COVERAGE FRIDAY AND
SATURDAY AFTERNOON.
AVERAGE AFTERNOON TEMPERATURES WILL BE CLOSE TO SEASONAL LEVELS WITH
ABUNDANT SUNSHINE AND DRY AIR. OVERNIGHT LOWS WEDNESDAY AND THURSDAY
NIGHT WILL RUN COOLER THAN NORMAL BY 10F OR SO. OVERNIGHT LOWS WILL
DROP INTO THE 50S WITH SOME MOUNTAIN VALLEYS DIPPING INTO THE 40S.
OVERNIGHT LOWS WILL RETURN TO NORMAL BY THE WEEKEND.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 200 PM EDT SUNDAY...
RADAR INDICATES SCATTERED SHOWERS ACROSS THE HIGHLANDS OF NORTH
CAROLINA INTO WESTERN VIRGINIA AND EXTREME SOUTHEAST WEST VIRGINIA...
SO FAR ONLY PASSING NEAR KBLF. RAPID UPDATE MODELS INDICATE THAT A
FEW OF THESE SHOWERS WILL INTENSIFY INTO THUNDERSTORMS FROM TIME
TO TIME THROUGH EARLY EVENING...AS COVERAGE OF RAINFALL SPREADS
NORTH AND EAST...POTENTIALLY CLIPPING KLWB...KBCB AND PERHAPS
KROA DURING THE EVENING. MAIN CONCERN IS LOCALLY HEAVY RAIN WITH
THIS ACTIVITY...WHICH WILL REDUCE SURFACE VISIBILITIES TO LESS
THAN 1SM FOR BRIEF PERIODS OF TIME.
CONVECTION WILL FADE WITH LOSS OF HEATING DURING LATE EVENING.
OVERNIGHT...EXPECT ANOTHER ROUND OF PATCHY FOG...MAINLY IN THE
RIVER VALLEYS AND OVER AREAS THAT RECEIVED SIGNIFICANT RAINFALL
THIS AFTERNOON. MID LEVEL CLOUDS MOVING IN AHEAD OF AN
APPROACHING COLD FRONT WILL KEEP FOG LOCALIZED.
A COLD FRONT WILL PASS FROM WEST TO EAST ACROSS THE CENTRAL
APPALACHIANS ON MONDAY. 12Z MODEL GUIDANCE MAINTAINS ONLY MODEST
COVERAGE OF SHOWER ACTIVITY AHEAD OF THE FRONT...AND WITH LIMITED
INSTABILITY...THUNDERSTORM ACTIVITY IS EXPECTED TO BE ISOLATED TO
WIDELY SCATTERED AT BEST. OVERALL...VFR CONDITIONS ARE EXPECTED...
ALTHOUGH ANY LOCALLY HEAVY RAIN WILL REDUCE VISIBILITIES FOR BRIEF
PERIODS OF TIME. DRIER AIR WILL RETURN TO THE AREA WITH FRONTAL
PASSAGE...RESULTING IN A DECREASE IN CLOUD COVER.
EXTENDED AVIATION DISCUSSION...
SURFACE HIGH PRESSURE BUILDS INTO THE AREA FOR THE TUESDAY
THROUGH THURSDAY TIME PERIOD. MOST AREAS SHOULD EXPERIENCE VFR
CONDITIONS. LATE NIGHT/EARLY MORNING PATCHY FOG WILL BE
POSSIBLE...BUT ANY THAT FORMS SHOULD DISSIPATE QUICKLY AFTER
SUNRISE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...NF/WP
SHORT TERM...MBS
LONG TERM...RCS
AVIATION...NF/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1216 PM CDT SUN AUG 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT SUN AUG 23 2015
MOST OF THE FORECAST SHIFT WAS SPENT TRYING TO BUILD IN DETAILS ON
THE TRENDS IN THE WEATHER FROM THE STRONG CYCLONE OVER THE
NORTHERN PART OF THE REGION. OVERALL...DIDNT GET THE STRENGTH OF
STORMS OUT OF THE SYSTEM...AND MARGINAL WIND SHEAR AT BEST AND
THIN INSTABILITY TONGUE HAD MUCH TO DO WITH THAT.
GOES WATER VAPOR SHOWING THE VIGOROUS SHORTWAVE TROUGH EJECTING
E-NE TOWARD KDLH AT 07Z WITH DEFORMATION PRECIPITATION SEEN ACROSS
ND IN REGIONAL RADARS. LOCALLY...THE COLD FRONT IS PUSHING TOWARD
ERN WI WITH LIGHT SHRA AHEAD OF THE FRONT AND SOME POST-FRONTAL
SHRA ABOUT A COUNTY FURTHER WEST. MULTIPLE FRONTOGENETIC BANDS
INDICATED IN THE RAP IN THE LOWER LEVELS. THESE WILL CONTINUE EAST
AND OUT OF THE FORECAST AREA DURING THE EARLY MORNING HOURS.
CLOUDS AND LOW-LEVEL SECONDARY TROUGH/FRONTAL AXIS ALONG
MN/DAKOTAS BORDER IS SHIFTING TOWARD THE AREA AS WELL. AS THE
SURFACE LOW SHIFTS EAST THROUGH SOUTHERN MANITOBA TODAY AND
FILLS...MANY OF THE FORCING FEATURES WEAKEN...INCLUDING THE
MN TROUGH AXIS AND CONVERGENCE ALONG IT. THE SYSTEM BECOMES A
BROAD CYCLONIC FLOW SCENARIO WITH ONLY A WEAK REMNANT TROUGH
AFFECTING NRN WI LATER THIS MORNING AND AFTERNOON. HAVE BROUGHT
SOME ISO-SCT SHRA BACK IN ALONG AND NORTH OF I-94 FOR MAINLY THE
17-22Z WINDOW. THERE IS SOME SUGGESTION IN THE HI-RES MODELS THAT
THIS COULD ALSO AFFECT CENTRAL WI. HAVE ALSO CONTINUED AFTERNOON
WIND GUSTS OF 25-35 MPH...REMAINING BELOW WIND ADVISORY CRITERIA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN AUG 23 2015
CONFIDENCE IS ABOVE AVERAGE THROUGH THURSDAY WITH QUIET WEATHER
EXPECTED AND BELOW NORMAL TEMPERATURES. ALONG AND NORTH OF I-94
TEMPERATURES WILL BE MUCH BELOW NORMAL. MONDAY WILL BE THE
COLDEST DAY BEFORE MODERATION SLOWLY OCCURS...ESPECIALLY WEDNESDAY
ON. HAVE LOWERED THE TEMPERATURES IN THE NORTH DOWN A NOTCH INTO
THE UPPER 50S FOR HIGHS MONDAY AS THE COLD AIR POCKET SLIPS
THROUGH UNDER THICK CLOUDS.
ON MONDAY..MAY HAVE TO TREND TOWARD HIGHER SHRA CHANCES NORTHEAST OF
I-94 MONDAY AFTERNOON DEPENDING ON THE TRACK OF WELL AGREED UPON
SHORTWAVE TROUGH ENERGY. THIS WAVE IS ACTUALLY THE CURRENT MN
VORTEX ROTATING AROUND THE LONGER WAVE TROUGH AND BACK IN FROM THE
NORTH MONDAY. CURRENTLY THE TRACK APPEARS TO FAVOR NORTHEASTERN WI
FOR SHRA...BUT WILL KEEP WATCH AS DIURNAL TIMING IS IDEAL FOR
ENHANCED SHRA COVERAGE. MONDAY AGAIN WILL SEE GUSTY NORTHWEST
WINDS OF 25-30 MPH IN THE AFTERNOON.
RIDGE BUILDING THEN BEGINS AND DOMINATES THROUGH THURSDAY.
SOME DIFFERENCES SHOW UP FRIDAY AND INTO SATURDAY. SOME RETURN
FLOW WARMING OCCURS AND THE GFS IS MORE AGGRESSIVE WITH RIDGE
BUILDING OVER THE NORTHERN CONUS. THE 23.00Z CANADIAN/ECMWF AND
21.18Z DGEX SOLUTIONS ARE AT ODDS WITH THE 23.00Z GFS...AS THEY
ALL HAVE A CUTOFF LOW DRIFTING E/SE THROUGH NEB/IA LATE IN THE
WEEK. HOWEVER...THE 23.00Z GEFS DOES HAVE SOME MEMBERS THAT PICK
UP ON THE LOW AS WELL...SO IT LOOKS LIKE THAT MAY BE A BETTER
SOLUTION FOR LATE WEEK. THIS WOULD BRING SOME RAIN CHANCES
POSSIBLY CLOSE OR INTO THE AREA. WILL HAVE TO LET THIS ALL SHAKE
OUT...AND WENT WITH CONSENSUS BLEND WHICH TURNS INTO SLIGHT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1216 PM CDT SUN AUG 23 2015
A SFC THRU UPPER LEVEL LOW OVER SOUTHWEST ONT AT MID-DAY WILL MOVE
SLOWLY EAST ACROSS ONT THRU TONIGHT/MON. WESTERN EDGE OF THE MVFR/
VFR STRATO-CU DECK WRAPPED AROUND THE SOUTHWEST SIDE OF THIS LOW WAS
NEAR I-35 AT 17Z. DISTANCE-SPEED TOOL MOVES THIS EAST OF KRST
BETWEEN 20-21Z AND THRU KLSE AROUND 00Z THIS EVENING. ONCE THESE
CLOUDS EXIT...GOOD...BUT BREEZY/WINDY...VFR CONDITIONS EXPECTED THRU
TONIGHT/MON MORNING. WEST-NORTHWEST WINDS 15-20KT G25-30KT WILL
DIMINISH WITH SUNSET TO 10-15KTS FOR TONIGHT/EARLY MON MORNING. BY
MID MORNING DIURNAL WARMING/MIXING WILL INCREASE WINDS TO AROUND
30015G25KT. SOUNDINGS SHOWING AS MUCH AS 30-35KTS OF WIND IN THE TOP
OF THE MIXED LAYER BY LATE MORNING/EARLY MON AFTERNOON. WINDS AFTER
16-17Z MON INTO THE AFTERNOON HOURS EXPECTED TO BE AROUND 30020G30KT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BAUMGARDT
AVIATION.....RRS