Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/22/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
943 AM MST THU AUG 20 2015
.SYNOPSIS...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY FROM
TUCSON EAST AND SOUTH THROUGH TONIGHT. INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL THEN BEGIN FRIDAY WITH THE BEST
CHANCE OF WIDESPREAD RAINFALL EARLY NEXT WEEK. THE INCREASED
MOISTURE WILL ALSO KEEP DAYTIME TEMPERATURES CLOSE TO SEASONAL
AVERAGES FRIDAY INTO EARLY NEXT WEEK.
&&
.DISCUSSION...SATELLITE IMAGERY WAS SHOWING SOME CLOUDS ALREADY
STARTING TO BUILD UP ACROSS FAR SOUTHEAST ARIZONA AND IN THE WHITE
MOUNTAINS THIS MORNING. MOISTURE WILL CONTINUE TO INCREASE TODAY AND
MORE SO THIS WEEKEND. THAT SAID...CHANCES OF RAIN WILL BE GOING UP
GRADUALLY STARTING TODAY. CURRENT FORECAST APPEARED TO HANDLE THE
TRENDS WELL...SO NO UPDATES NECESSARY THIS MORNING. PLEASE REFER TO
THE ADDITIONAL SECTIONS FOR MORE DETAILS.
&&
.AVIATION...VALID THRU 21/12Z.
FEW-SCT CLOUDS ABV 12K FT. AFT 20/21Z SCT TO LOCALLY BKN 8-10K FT
AND SCT-BKN LYRS AOA 12K FT. CHANCE FOR -SHRA/-TSRA FROM KTUS SOUTH
AND EAST...WITH AN EMPHASIS ON THE SOUTHERN TERMINALS KOLS AND KDUG.
BRIEF MVFR CONDITIONS AND GUSTY WINDS MAY BE POSSIBLE NEAR STRONGER
TSRA. OTHERWISE...WINDS WILL GENERALLY BE LIGHT AND TERRAIN DRIVEN
UNDER 10 KTS EXCEPT WLY 6-13KTS 20/21Z THRU 21/03Z. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOISTURE WILL START TO INCREASE TODAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS POSSIBLE...MAINLY SOUTHERN AREAS. THEN
THE MOISTURE AND THUNDERSTORMS CHANCES WILL INCREASE AND SPREAD
THROUGHOUT SOUTHEAST ARIZONA THROUGH THE WEEKEND INTO EARLY NEXT
WEEK. WINDS WILL BE TYPICAL FOR MID AUGUST AND GENERALLY LESS THAN
15 MPH THEN THE WIND WILL BECOME EASTERLY MONDAY AND TUESDAY...BUT
AGAIN GENERALLY REMAINING 15 MPH OR LESS.
&&
.PREV DISCUSSION...BASED ON VARIOUS NWP SOLUTIONS...THERE WERE NO
SIGNIFICANT ADJUSTMENTS TO THE INHERITED GRIDDED DATA
POP/WEATHER/TEMP FIELDS FOR THIS FORECAST ISSUANCE. HIGH PRESSURE
ALOFT CENTERED NEAR THE NRN BAJA CALIFORNIA COAST WILL WEAKEN INTO
THIS WEEKEND. THE DRY NWLY FLOW GENERALLY IN THE 700-300MB LAYER
WILL TRANSITION TO LIGHT WLY FLOW FRI AND CONTINUE SAT.
FOR TODAY AND TONIGHT...SEVERAL HRRR SOLUTIONS SUGGEST AN EARLY
START TO SHOWER/TSTM ACTIVITY...PERHAPS BY 18Z-19Z SOUTH-TO-
SOUTHEAST OF TUCSON AND ESPECIALLY FAVORING SANTA CRUZ/SWRN COCHISE
COUNTIES BY MID-AFTERNOON. MEANWHILE...THERE SHOULD BE ENOUGH
MOISTURE TO JUSTIFY ISOLATED SHOWERS/TSTMS THIS AFTERNOON INTO
TONIGHT FROM TUCSON EAST TO THE NEW MEXICO BORDER. PRECIP-FREE
CONDITIONS WILL CONTINUE ACROSS WRN PIMA COUNTY.
20/00Z GFS/ECMWF/CMC SUGGEST THAT PRECIP COVERAGE SHOULD INCREASE
STARTING FRI FOLLOWED BY SCATTERED TO PERHAPS NUMEROUS SHOWERS/
TSTMS...ESPECIALLY SUN INTO MON NIGHT OR SO. THIS SCENARIO SEEMS
REASONABLE GIVEN THAT THE MID AND UPPER FLOW IS PROGGED TO BECOME
ELY/SELY STARTING SUN AND CONTINUING EARLY NEXT WEEK. HAVE NOTED
SOME DISCREPANCIES BETWEEN THE GFS/ECMWF SOLUTIONS FOR EARLY NEXT
WEEK. IN GENERAL...THE 20/00Z GFS TRENDED SOMEWHAT DRIER VERSUS
PREVIOUS GFS SOLUTIONS FOR QPF/S SUN-MON...AND THE 20/00Z ECMWF WAS
MARKEDLY MORE ROBUST WITH QPF/S FOR MON-TUE VERSUS THE 20/00Z GFS.
BASED ON THESE DIFFERENCES...OPTED TO MAKE ONLY VERY MINOR
MODIFICATIONS TO THE GRIDDED DATA POPS SUN-TUE. AT THIS TIME...
APPEARS THAT THE BEST COVERAGE OF SHOWERS/TSTMS SHOULD OCCUR ROUGHLY
SUN AFTERNOON INTO MON NIGHT...OR PERHAPS EARLY TUE. THEREAFTER...
THE GFS TRANSITIONED THE UPPER HIGH CENTER FROM NEAR THE FOUR
CORNERS REGION INTO SERN NEW MEXICO/WEST TEXAS NEXT WED. SWLY FLOW
ALOFT ASSOCIATED WITH THIS SCENARIO WOULD CONFINE SHOWERS/TSTMS
MAINLY TO ERN SECTIONS BY NEXT WED. HOWEVER...THE ECMWF MAINTAINED
THE UPPER HIGH TO BE CENTERED NEAR THE FOUR CORNERS. SLY/SELY FLOW
ALOFT ASSOCIATED WITH THIS SCENARIO WOULD KEEP PRECIP CHANCES HIGHER
FURTHER WWD VERSUS THE GFS SOLUTION. THE UPSHOT...ISOLATED TO
SCATTERED SHOWERS/TSTMS AREA-WIDE NEXT WED...WITH HIGHER POPS ACROSS
GREENLEE/GRAHAM/COCHISE COUNTIES.
HIGH TEMPS TODAY WILL BE QUITE SIMILAR TO TEMPS ACHIEVED WED... AND
WILL CONTINUE TO AVERAGE ABOUT 2-5 DEGS F ABOVE NORMAL. SOME MINOR
COOLING WILL THEN OCCUR FRI FOLLOWED BY NEAR NORMAL DAYTIME TEMPS
FOR MUCH OF THE AREA SAT-TUE. HIGH TEMPS SHOULD TREND UPWARD AND
GENERALLY A FEW DEGS ABOVE NORMAL NEXT WED.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS TUCSON AZ
405 AM MST THU AUG 20 2015
.SYNOPSIS...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS MAINLY FROM
TUCSON EAST AND SOUTH THROUGH TONIGHT. INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL THEN BEGIN FRIDAY WITH THE BEST
CHANCE OF WIDESPREAD RAINFALL EARLY NEXT WEEK. THE INCREASED
MOISTURE WILL ALSO KEEP DAYTIME TEMPERATURES CLOSE TO SEASONAL
AVERAGES FRIDAY INTO EARLY NEXT WEEK.
&&
.DISCUSSION...IR SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATED CLEAR SKIES ACROSS MUCH OF SE ARIZONA AT THIS TIME. THE
EXCEPTION WAS SOME CIRRIFORM CLOUDINESS MAINLY ACROSS THE WHITE
MOUNTAINS...AND SOME MID-LEVEL CLOUDS NEAR THE INTERNATIONAL BORDER
ADJACENT SANTA CRUZ/COCHISE COUNTIES. CLOUD TOPS ASSOCIATED WITH A
CONVECTIVE COMPLEX OVER EAST CENTRAL SONORA HAVE BEEN WARMING DURING
THE PAST 1-2 HOURS. THIS SYSTEM LIKELY SENT AN OUTFLOW NWD...WITH
LIGHTNING DETECTED DURING THE PAST 60-90 MINUTES IN NERN SONORA SW
OF DOUGLAS.
BASED ON VARIOUS NWP SOLUTIONS...THERE WERE NO SIGNIFICANT
ADJUSTMENTS TO THE INHERITED GRIDDED DATA POP/WEATHER/TEMP FIELDS
FOR THIS FORECAST ISSUANCE. HIGH PRESSURE ALOFT CENTERED NEAR THE
NRN BAJA CALIFORNIA COAST WILL WEAKEN INTO THIS WEEKEND. THE DRY
NWLY FLOW GENERALLY IN THE 700-300MB LAYER WILL TRANSITION TO
LIGHT WLY FLOW FRI AND CONTINUE SAT.
FOR TODAY AND TONIGHT...SEVERAL HRRR SOLUTIONS SUGGEST AN EARLY
START TO SHOWER/TSTM ACTIVITY...PERHAPS BY 18Z-19Z SOUTH-TO-
SOUTHEAST OF TUCSON AND ESPECIALLY FAVORING SANTA CRUZ/SWRN COCHISE
COUNTIES BY MID-AFTERNOON. MEANWHILE...THERE SHOULD BE ENOUGH
MOISTURE TO JUSTIFY ISOLATED SHOWERS/TSTMS THIS AFTERNOON INTO
TONIGHT FROM TUCSON EAST TO THE NEW MEXICO BORDER. PRECIP-FREE
CONDITIONS WILL CONTINUE ACROSS WRN PIMA COUNTY.
20/00Z GFS/ECMWF/CMC SUGGEST THAT PRECIP COVERAGE SHOULD INCREASE
STARTING FRI FOLLOWED BY SCATTERED TO PERHAPS NUMEROUS SHOWERS/
TSTMS...ESPECIALLY SUN INTO MON NIGHT OR SO. THIS SCENARIO SEEMS
REASONABLE GIVEN THAT THE MID AND UPPER FLOW IS PROGGED TO BECOME
ELY/SELY STARTING SUN AND CONTINUING EARLY NEXT WEEK. HAVE NOTED
SOME DISCREPANCIES BETWEEN THE GFS/ECMWF SOLUTIONS FOR EARLY NEXT
WEEK. IN GENERAL...THE 20/00Z GFS TRENDED SOMEWHAT DRIER VERSUS
PREVIOUS GFS SOLUTIONS FOR QPF/S SUN-MON...AND THE 20/00Z ECMWF WAS
MARKEDLY MORE ROBUST WITH QPF/S FOR MON-TUE VERSUS THE 20/00Z GFS.
BASED ON THESE DIFFERENCES...OPTED TO MAKE ONLY VERY MINOR
MODIFICATIONS TO THE GRIDDED DATA POPS SUN-TUE. AT THIS TIME...
APPEARS THAT THE BEST COVERAGE OF SHOWERS/TSTMS SHOULD OCCUR ROUGHLY
SUN AFTERNOON INTO MON NIGHT...OR PERHAPS EARLY TUE. THEREAFTER...
THE GFS TRANSITIONED THE UPPER HIGH CENTER FROM NEAR THE FOUR
CORNERS REGION INTO SERN NEW MEXICO/WEST TEXAS NEXT WED. SWLY FLOW
ALOFT ASSOCIATED WITH THIS SCENARIO WOULD CONFINE SHOWERS/TSTMS
MAINLY TO ERN SECTIONS BY NEXT WED. HOWEVER...THE ECMWF MAINTAINED
THE UPPER HIGH TO BE CENTERED NEAR THE FOUR CORNERS. SLY/SELY FLOW
ALOFT ASSOCIATED WITH THIS SCENARIO WOULD KEEP PRECIP CHANCES HIGHER
FURTHER WWD VERSUS THE GFS SOLUTION. THE UPSHOT...ISOLATED TO
SCATTERED SHOWERS/TSTMS AREA-WIDE NEXT WED...WITH HIGHER POPS ACROSS
GREENLEE/GRAHAM/COCHISE COUNTIES.
HIGH TEMPS TODAY WILL BE QUITE SIMILAR TO TEMPS ACHIEVED WED...
AND WILL CONTINUE TO AVERAGE ABOUT 2-5 DEGS F ABOVE NORMAL. SOME
MINOR COOLING WILL THEN OCCUR FRI FOLLOWED BY NEAR NORMAL DAYTIME
TEMPS FOR MUCH OF THE AREA SAT-TUE. HIGH TEMPS SHOULD TREND UPWARD
AND GENERALLY A FEW DEGS ABOVE NORMAL NEXT WED.
&&
.AVIATION...VALID THRU 21/06Z.
FEW-SCT CLOUDS ABV 12K FT. AFT 20/21Z SCT TO LOCALLY BKN 8-10K FT
AND SCT-BKN LYRS AOA 12K FT. CHANCE FOR -SHRA/-TSRA FROM KTUS SOUTH
AND EAST...WITH AN EMPHASIS ON THE SOUTHERN TERMINALS KOLS AND KDUG.
BRIEF MVFR CONDITIONS AND GUSTY WINDS MAY BE POSSIBLE NEAR STRONGER
TSRA. OTHERWISE...WINDS WILL GENERALLY BE LIGHT AND TERRAIN DRIVEN
UNDER 10 KTS EXCEPT WLY 6-13KTS 20/21Z THRU 21/03Z. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...MOISTURE WILL START TO INCREASE TODAY WITH ISOLATED
SHOWERS AND THUNDERSTORMS POSSIBLE...MAINLY SOUTHERN AREAS. THEN
THE MOISTURE AND THUNDERSTORMS CHANCES WILL INCREASE AND SPREAD
THROUGHOUT SOUTHEAST ARIZONA THROUGH THE WEEKEND INTO EARLY NEXT
WEEK. WINDS WILL BE TYPICAL FOR MID AUGUST AND GENERALLY LESS THAN
15 MPH THEN THE WIND WILL BECOME EASTERLY MONDAY AND TUESDAY...BUT
AGAIN GENERALLY REMAINING 15 MPH OR LESS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
AVIATION/FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1045 PM EDT FRI AUG 21 2015
.UPDATE...
SHOWERS HAVE DISSIPATED FOR NOW. WITH THE MOIST AIR MASS AND LINGERING
MARGINAL INSTABILITY...HAVE EXTENDED A SLIGHT CHANCE OF SHOWERS AND
A FEW THUNDERSTORMS THROUGH THE NIGHT. OTHERWISE NO CHANGES.
41
PREVIOUS...
.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...
00Z UPDATE...
CONVECTION HAS DIMINISHED AND MAY NOT AFFECT THE TAF SITES DURING
THE NIGHT...ALTHOUGH A SLIGHT CHANCE REMAINS IN THE FORECAST.
EXPECTING VFR OVERNIGHT BUT THERE COULD BE SOME MVFR FOG TOWARD 09Z.
DIURNAL CUMULUS SATURDAY WITH A SLIGHT CHANCE OF AFTERNOON CONVECTION.
VARIABLE OR LIGHT NORTHWEST WINDS OVERNIGHT AND NORTHWEST TO NORTH
WINDS SATURDAY LESS THAN 10KT.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM TO HIGH ON ALL ELEMENTS.
41
&&
.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...41
LONG TERM....BDL
AVIATION...41
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
750 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...
00Z UPDATE...
CONVECTION HAS DIMINISHED AND MAY NOT AFFECT THE TAF SITES DURING
THE NIGHT...ALTHOUGH A SLIGHT CHANCE REMAINS IN THE FORECAST.
EXPECTING VFR OVERNIGHT BUT THERE COULD BE SOME MVFR FOG TOWARD 09Z.
DIURNAL CUMULUS SATURDAY WITH A SLIGHT CHANCE OF AFTERNOON CONVECTION.
VARIABLE OR LIGHT NORTHWEST WINDS OVERNIGHT AND NORTHWEST TO NORTH
WINDS SATURDAY LESS THAN 10KT.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM TO HIGH ON ALL ELEMENTS.
41
&&
.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...41
LONG TERM....BDL
AVIATION...41
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
359 PM EDT THU AUG 20 2015
.SYNOPSIS...
DEEP MOISTURE WILL REMAIN IN THE FORECAST AREA THROUGH FRIDAY.
A WEAK FRONT APPROACHING FROM THE NORTHWEST WILL MOVE INTO THE
AREA TONIGHT AND REMAIN NEAR THE REGION DURING THE REST OF THE
WEEKEND. THERE WILL BE A CONTINUED CHANCE OF SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
CONVERGENCE ASSOCIATED WITH A PREFRONTAL TROUGH AND HEATING WILL
HELP CAUSE THUNDERSTORMS INTO THE EVENING. SOME CONTINUED
CONVERGENCE NEAR THE WEAK FRONT MOVING INTO THE AREA SUPPORTS A
CONTINUED CHANCE OVERNIGHT. THE MIDAFTERNOON WATER VAPOR IMAGERY
SHOWED SOME DRYING OVER THE AREA INDICATING WE ARE BETWEEN AREAS
OF UPPER-LEVEL LIFT. BELIEVE SOME UPPER-LEVEL LIFT WILL OVERSPREAD
THE REGION TONIGHT AS INDICATED BY WATER VAPOR IMAGERY TRENDS AND
MODEL GUIDANCE SHOWING SHORTWAVE TROUGHS MOVING INTO THE H5 RIDGE
EARLY AND AGAIN TOWARD MORNING. THE HRRR DISPLAYED SCATTERED
COVERAGE INTO THE EVENING. THE SPC WRF SHOWED NUMEROUS SHOWERS AND
THUNDERSTORMS TONIGHT. WE LEANED TOWARD THE HIGHER GUIDANCE POPS.
THE MAIN FORECAST PROBLEM THROUGH TONIGHT IS THE THREAT OF HEAVY
RAIN BECAUSE OF PRECIPITABLE WATER NEAR 2 INCHES AND POSSIBLE
TRAINING. THERE IS LESS OF A DAMAGING WIND THREAT WITH A FORECAST
SOUNDING CLOSE TO MOIST ADIABATIC. THE HIGH MOISTURE FAVORED THE
WARMER TEMPERATURE GUIDANCE TONIGHT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
BELIEVE THE DIFFUSE FRONT WILL REMAIN STALLED NEAR THE FORECAST
AREA. MOISTURE MAY BECOME MORE SHALLOW...ESPECIALLY IN THE NORTH.
THE NAM INDICATED LESS DRYING COMPARED TO THE GFS. THE PATTERN
FAVORS THE SLOWER TIMING AND WE LEANED TOWARD THE HIGHER MOS
POPS...MAINLY IN THE SOUTH PART WHERE EXPECT MORE MOISTURE AND
GREATER CONVERGENCE ASSOCIATED WITH THE WEAK FRONT.
PRECIPITABLE WATER REMAINING NEAR 2 INCHES INDICATES A
CONTINUED THREAT OF THUNDERSTORMS WITH LOCALLY HEAVY RAIN. USED
THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST AND
WARMER GUIDANCE FOR THE LOW TEMPERATURE BECAUSE OF THE RECENT BIAS
AND MOIST AIR MASS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
MOISTURE ASSOCIATED WITH THE REMNANTS OF THE FRONT SHOULD
CONTINUE THROUGH SUNDAY. THE GFS AND ECMWF DISPLAY ANOTHER FRONT
MOVING INTO THE AREA MONDAY WITH THIS FEATURE LINGERING NEAR THE
AREA DURING THE REST OF THE MEDIUM-RANGE PERIOD. HOWEVER...DEEPER
MOISTURE APPEARS TO REMAIN EAST OF THE FORECAST AREA AHEAD OF THE
UPPER TROUGH. THE GFS...ECMWF...AND EKD MOS HAVE POPS OF 20 TO 30
PERCENT THROUGH THE PERIOD.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS EXPECTED FOR MUCH OF THE PERIOD...WITH
RESTRICTIONS POSSIBLE IN AFTERNOON AND EVENING CONVECTION.
CONVERGENCE AHEAD OF AN APPROACHING FRONTAL BOUNDARY COMBINED
WITH DIURNAL HEATING AND ELEVATED MOISTURE WILL PROMOTE CONVECTION
THIS AFTERNOON AND EVENING. MOST OF THE CONVECTION SO FAR HAS BEEN
EAST OF CAE/CUB/AGS/DNL...BUT EXPECT MORE COVERAGE FURTHER WEST
LATER THIS AFTERNOON AND EVENING DUE TO INCREASED UPPER ENERGY.
HAVE ONLY INCLUDED A TEMPO GROUP FOR THUNDERSTORMS AT OGB AS
CONFIDENCE IN TIMING AND COVERAGE REMAINS TOO LOW TO INCLUDE AT
OTHER TAF SITES. THE FRONTAL BOUNDARY WILL CROSS THE TAF SITES
OVERNIGHT WITH CONVECTION DIMINISHING. CANNOT RULE OUT
RESTRICTIONS IN STRATUS/FOG EARLY FRIDAY ALTHOUGH A 20-KNOT LOW
LEVEL JET SHOULD LIMIT FOG POTENTIAL. WINDS WILL BE OUT OF THE
WEST-SOUTHWEST AT 5 TO 10 KNOTS THROUGH THIS EVENING AND WILL
ROTATE TO NORTHERLY OVERNIGHT AS THE FRONT MOVES INTO THE AREA.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN ON FRIDAY AS THE
FRONT LINGERS NEAR THE AREA.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE FRIDAY IN
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1038 AM EDT THU AUG 20 2015
.SYNOPSIS...
DEEP MOISTURE WILL REMAIN IN THE FORECAST AREA THROUGH FRIDAY.
A WEAK FRONT APPROACHING FROM THE NORTHWEST WILL MOVE INTO THE
AREA TONIGHT AND REMAIN NEAR THE REGION DURING THE REST OF THE
WEEKEND. THERE WILL BE A CONTINUED CHANCE OF SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS MORNING/S ANALYSIS SHOWED A COLD FRONT ALONG THE MOUNTAINS. A
PREFRONTAL TROUGH EXTENDED THROUGH WESTERN SOUTH CAROLINA
SOUTHWARD INTO EASTERN GEORGIA. A TONGUE OF HIGHER DEW POINT
TEMPERATURES EXTENDED FROM COASTAL GEORGIA NORTHWESTWARD INTO THE
CENTRAL SAVANNAH RIVER AREA. THE HRRR DISPLAYED DEVELOPMENT FIRST
IN THIS AREA EARLY THIS AFTERNOON WHICH APPEARS REASONABLE BECAUSE
OF CONVERGENCE INTO THE PREFRONTAL TROUGH AND HIGHER MOISTURE.
THIS MORNING/S WATER VAPOR IMAGERY SHOWED SOME MID-LEVEL DRYING
INDICATED WE MAY REMAIN BETWEEN GREATER UPPER-LEVEL LIFT THIS
AFTERNOON. FORECASTED CHANCE POPS NORTH TO LIKELY IN THE CSRA THIS
AFTERNOON. THE SPC WRF DISPLAYED CONSIDERABLE COVERAGE OF SHOWERS
AND THUNDERSTORMS TONIGHT WHICH MAY BE CORRECT BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE WEAK FRONT MOVING INTO THE AREA
AND SOME UPPER-LEVEL LIFT AHEAD OF THE NEXT SHORTWAVE TROUGH.
THE MAIN FORECAST PROBLEM THROUGH TONIGHT IS THE THREAT OF HEAVY
RAIN BECAUSE OF PRECIPITABLE WATER NEAR 2 INCHES AND POSSIBLE
TRAINING. THERE IS LESS OF A DAMAGING WIND THREAT WITH A FORECAST
SOUNDING CLOSE TO MOIST ADIABATIC.
USED THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST
TODAY. THE HIGH MOISTURE FAVORED THE WARMER TEMPERATURE GUIDANCE
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
BELIEVE THE DIFFUSE FRONT WILL REMAIN STALLED NEAR THE
FORECAST AREA. MOISTURE MAY BECOME MORE SHALLOW...ESPECIALLY IN
THE NORTH. THE NAM INDICATED LESS DRYING COMPARED TO THE GFS. THE
PATTERN FAVORS THE SLOWER TIMING AND WE LEANED TOWARD THE HIGHER
MOS POPS. PRECIPITABLE WATER REMAINING NEAR 2 INCHES INDICATES A
CONTINUED THREAT OF THUNDERSTORMS WITH LOCALLY HEAVY RAIN. USED
THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST AND
WARMER GUIDANCE FOR THE LOW TEMPERATURE BECAUSE OF THE RECENT BIAS
AND MOIST AIR MASS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MOISTURE ASSOCIATED WITH THE REMNANTS OF THE FRONT SHOULD
CONTINUE THROUGH SUNDAY. THE GFS AND ECMWF DISPLAY ANOTHER FRONT
MOVING INTO THE AREA MONDAY WITH THIS FEATURE LINGERING NEAR THE
AREA DURING THE REST OF THE MEDIUM-RANGE PERIOD. HOWEVER...DEEPER
MOISTURE APPEARS TO REMAIN EAST OF THE FORECAST AREA AHEAD OF THE
UPPER TROUGH. THE GFS...ECMWF...AND EKD MOS HAVE POPS OF 20 TO 30
PERCENT THROUGH THE PERIOD.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS EXPECTED FOR MUCH OF THE PERIOD...WITH LOW
CONFIDENCE IN RESTRICTIONS IN AFTERNOON AND EVENING CONVECTION.
MAIN CONCERN TODAY IS POTENTIAL FOR AFTERNOON CONVECTION...WITH
FRONTAL BOUNDARY APPROACHING FROM THE NORTHWEST CONVECTION WILL BE
POSSIBLE THIS AFTERNOON AND EVENING. CONFIDENCE IN TIMING AND
COVERAGE REMAINS TOO LOW TO INCLUDE IN TAFS. CONVECTION WILL
DIMINISH WITH SUNSET AND THE FRONTAL BOUNDARY CROSSING THE TAF
SITES OVERNIGHT. WINDS WILL BE OUT OF THE WEST-SOUTHWEST TODAY AT
5 TO 10 KNOTS AND WILL ROTATE TO NORTHERLY OVERNIGHT AS THE FRONT
MOVES INTO THE AREA.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE FRIDAY MORNING
IN FOG AND/OR STRATUS...AND SCATTERED MAINLY AFTERNOON AND
EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
928 AM EDT THU AUG 20 2015
.SYNOPSIS...
DEEP MOISTURE WILL REMAIN IN THE FORECAST AREA THROUGH FRIDAY.
A WEAK FRONT APPROACHING FROM THE NORTHWEST WILL MOVE INTO THE
AREA TONIGHT AND REMAIN NEAR THE REGION DURING THE REST OF THE
WEEKEND. THERE WILL BE A CONTINUED CHANCE OF SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS MORNING/S ANALYSIS SHOWED A COLD FRONT ALONG THE MOUNTAINS. A
PREFRONTAL TROUGH EXTENDED THROUGH WESTERN SOUTH CAROLINA
SOUTHWARD INTO EASTERN GEORGIA. A TONGUE OF HIGHER DEW POINT
TEMPERATURES EXTENDED FROM COASTAL GEORGIA NORTHWESTWARD INTO THE
CENTRAL SAVANNAH RIVER AREA. THE HRRR DISPLAYED DEVELOPMENT FIRST
IN THIS AREA EARLY THIS AFTERNOON WHICH APPEARS REASONABLE BECAUSE
OF CONVERGENCE INTO THE PREFRONTAL TROUGH AND HIGHER MOISTURE.
THIS MORNING/S WATER VAPOR IMAGERY SHOWED SOME MID-LEVEL DRYING
INDICATED WE MAY REMAIN BETWEEN GREATER UPPER-LEVEL LIFT THIS
AFTERNOON. FORECASTED CHANCE POPS NORTH TO LIKELY IN THE CSRA THIS
AFTERNOON. THE SPC WRF DISPLAYED CONSIDERABLE COVERAGE OF SHOWERS
AND THUNDERSTORMS TONIGHT WHICH MAY BE CORRECT BECAUSE OF
CONVERGENCE ASSOCIATED WITH THE WEAK FRONT MOVING INTO THE AREA
AND SOME UPPER-LEVEL LIFT AHEAD OF THE NEXT SHORTWAVE TROUGH.
THE MAIN FORECAST PROBLEM THROUGH TONIGHT IS THE THREAT OF HEAVY
RAIN BECAUSE OF PRECIPITABLE WATER NEAR 2 INCHES AND POSSIBLE
TRAINING. THERE IS LESS OF A DAMAGING WIND THREAT WITH A FORECAST
SOUNDING CLOSE TO MOIST ADIABATIC.
USED THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST
TODAY. THE HIGH MOISTURE FAVORED THE WARMER TEMPERATURE GUIDANCE
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
BELIEVE THE DIFFUSE FRONT WILL REMAIN STALLED NEAR THE
FORECAST AREA. MOISTURE MAY BECOME MORE SHALLOW...ESPECIALLY IN
THE NORTH. THE NAM INDICATED LESS DRYING COMPARED TO THE GFS. THE
PATTERN FAVORS THE SLOWER TIMING AND WE LEANED TOWARD THE HIGHER
MOS POPS. PRECIPITABLE WATER REMAINING NEAR 2 INCHES INDICATES A
CONTINUED THREAT OF THUNDERSTORMS WITH LOCALLY HEAVY RAIN. USED
THE GUIDANCE CONSENSUS FOR THE HIGH TEMPERATURE FORECAST AND
WARMER GUIDANCE FOR THE LOW TEMPERATURE BECAUSE OF THE RECENT BIAS
AND MOIST AIR MASS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MOISTURE ASSOCIATED WITH THE REMNANTS OF THE FRONT SHOULD
CONTINUE THROUGH SUNDAY. THE GFS AND ECMWF DISPLAY ANOTHER FRONT
MOVING INTO THE AREA MONDAY WITH THIS FEATURE LINGERING NEAR THE
AREA DURING THE REST OF THE MEDIUM-RANGE PERIOD. HOWEVER...DEEPER
MOISTURE APPEARS TO REMAIN EAST OF THE FORECAST AREA AHEAD OF THE
UPPER TROUGH. THE GFS...ECMWF...AND EKD MOS HAVE POPS OF 20 TO 30
PERCENT THROUGH THE PERIOD.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS EXPECTED FOR MUCH OF THE PERIOD...WITH LOW
CONFIDENCE IN RESTRICTION IN AFTERNOON AND EVENING CONVECTION.
MID CLOUDS HAVE PERSISTED OVERNIGHT RESULTING IN LESS FOG AND
STRATUS FORMATION THIS MORNING. NEXT CONCERN WILL BE POTENTIAL FOR
AFTERNOON CONVECTION...WITH FRONTAL BOUNDARY APPROACHING FROM THE
NORTHWEST CONVECTION WILL BE POSSIBLE THIS AFTERNOON AND EVENING.
CONFIDENCE IN TIMING AND COVERAGE REMAINS TOO LOW TO INCLUDE IN
TAFS. CONVECTION WILL DIMINISH WITH SUNSET AND THE FRONTAL
BOUNDARY CROSSING THE TAF SITES OVERNIGHT.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE FRIDAY MORNING
IN FOG AND/OR STRATUS...AND SCATTERED MAINLY AFTERNOON AND
EVENING THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
653 PM CDT FRI AUG 21 2015
...UPDATED AVIATION SECTION...
.SHORT TERM...(THIS EVENING THROUGH Saturday)
ISSUED AT 233 PM CDT FRI AUG 21 2015
A few weak shortwaves were moving into the Central and Southern
Plains this afternoon from Colorado. The stronger one is moving into
the Oklahoma and Texas Panhandle, then into western Oklahoma this
afternoon and evening. The other one is forecast to move across
Nebraska and northern Kansas tonight. Some scattered thunderstorms
will continue mainly south and east of Dodge City later this
afternoon and evening, with another area possibly moving towards
Scott City to the I-70 corridor late tonight. Will continue with
small pops to cover for now. Some model solutions suggest an MCS
moving southeastward toward Dodge City by around midnight, but
question is how fast will the thunderstorms fall apart after
sunset in northwest Kansas with a fairly good warm capping
inversion in place. As far as severe potential goes for tonight,
if storms can persist across northwest Kansas and move towards
Dodge City, some may be marginally severe early this evening, but
after sunset should be below severe limits with fairly weak layer
wind shear. South winds of 12 to 22 mph will persist tonight under
partly cloudy to mostly cloudy skies. Overnight lows will be in
the mid to upper 60s.
For Saturday, a strong upper level shortwave trough will be moving
east from the Intermountain West and into the Northern Plains and
part of the Central Plains of Nebraska and northern Kansas. This
feature will push a cold front into northwest Kansas by evening.
Some storms along and just ahead of the front could be marginally
severe from near Syracuse to Scott City and Wakeeney by late
afternoon. Highs look to be in the low to mid 90s with south winds
of 15 to 25 mph ahead of the cold front.
.LONG TERM...(Saturday NIGHT THROUGH Friday)
ISSUED AT 307 PM CDT FRI AUG 21 2015
For Saturday night, a cold front will continue to drop southeastward
across western Kansas as a strong shortwave trough moves east. Will
continue to carry 60 to 70 percent chances for showers and
thunderstorms. Some storms could be marginally severe in the evening
and some with heavy rainfall potential. The storms should end by
Sunday morning early at Medicine Lodge. South winds will shift to
the north at 15 to 25 mph with the front. Lows will be in the mid to
upper 60s under mostly cloudy skies.
For the period of Sunday into next Thursday, storm chances will be
minimal. Cool surface high pressure will be in control on Sunday,
then a trough of low pressure will persist in the lee of the Rockies
into Thursday with low level moisture moving back into western
Kansas. Highs will warm from around 80 on Sunday, then back into the
upper 80s to around 90 into Thursday. Lows in the 50s on Monday
morning warm back into the 60s.
The chances for thunderstorms increase next Friday into the Weekend,
as as an upper ridge begins to break down across the Intermountain
West and chances for MCS (mesoscale convective systems) activity
moves over the top of the ridge into the Central Plains.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Saturday EVENING)
ISSUED AT 651 PM CDT FRI AUG 21 2015
Significant differences exist between he convective allowing models
this evening, perhaps enhanced by low level jet dynamics. TEMPO
periods for convection may need to be added or amended to TAF sites
GCK and DDC if the HRRR or 4 km NAM models verify even closely. The
ARW is far less aggressive and really doesn`t produce convection.
Southerly surface winds will be the prevailing direction with
gustiness diurnally.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 66 92 60 79 / 30 10 60 10
GCK 65 94 60 79 / 20 20 60 0
EHA 64 95 61 78 / 10 10 40 10
LBL 66 95 63 79 / 20 10 50 10
HYS 68 93 58 81 / 20 30 50 0
P28 69 93 65 81 / 30 10 60 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Kruse
LONG TERM...Kruse
AVIATION...Russell
AREA FORECAST DISCUSSION
NWS JACKSON KY
315 AM EDT THU AUG 20 2015
.UPDATE...
ISSUED AT 315 AM EDT THU AUG 20 2015
UPDATED FOR PRECIP TRENDS. AN AREA OF SHOWERS IS SLOWLY MAKING
PROGRESS TOWARD THE AREA FROM THE WEST AND WILL BRING MANY
LOCATIONS PRECIP OVERNIGHT. PRECIP WILL CUT OFF FROM WEST TO EAST
ON THURSDAY. BASED ON 00Z MODELS...HAVE TRIMMED DOWN POPS A BIT
FASTER ON THURSDAY.
UPDATE ISSUED AT 1055 PM EDT WED AUG 19 2015
CONVECTION HAS FILLED IN ACROSS EASTERN TENNESSEE AND PORTIONS OF
SOUTHEAST KENTUCKY OVER THE PAST HOUR. HAVE INCREASED POPS TO
ACCOUNT FOR THIS ACTIVITY. MORE DEVELOPMENT IS ALSO OCCURRING BACK
ACROSS WESTERN KENTUCKY OUT AHEAD OF THE APPROACHING COLD FRONT.
HAVE MADE SOME MINOR ADJUSTMENTS IN THE POPS THROUGH THE REST OF
THE NIGHT...BASED ON THE LATEST RADAR AND HIGHER RESOLUTION MODEL
TRENDS. THIS WILL KEEP MAINLY LIKELY POPS ACROSS THE AREA THROUGH
DAWN AS THE FRONT APPROACHES FROM THE WEST AND NORTHWEST.
UPDATE ISSUED AT 819 PM EDT WED AUG 19 2015
FRESHENED UP THE HOURLY POPS ACCORDING TO THE LATEST RADAR TRENDS.
A CLUSTER OF SHOWERS AND STORMS IS CURRENTLY ALIGNED NEAR THE I-75
CORRIDOR...WITH MORE WIDESPREAD CONVECTION DOWN IN TENNESSEE. THE
LATEST HRRR YIELDS A GENERAL WEAKENING TREND THROUGH EARLY THIS
EVENING...WITH OUR SOUTHWEST SEEING THE BEST AREAL COVERAGE
THROUGH THIS EVENING. HAVE USED A BLEND OF THE HRRR AND GENERAL
EXTRAPOLATION FROM THE MOSAIC RADAR FOR THE POPS OVER THE NEXT
SEVERAL HOURS...BEFORE BLENDING INTO THE INHERITED FORECAST.
UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 311 PM EDT WED AUG 19 2015
AREA OF LOW PRESSURE CONTINUES TO PUSH NORTHEAST ACROSS THE
NORTHERN GREAT LAKES...WITH A TRAILING COLD FRONT STRETCHING BACK
SOUTH ACROSS ILLINOIS AND MISSOURI THIS AFTERNOON. THIS FRONT WILL
BE THE FOCUS FOR OUR WEATHER OVER THE NEXT 18 TO 24 HOURS AS IT
CONTINUES TO PUSH EAST. PLENTY OF MOISTURE CONTINUES TO REMAIN
AHEAD OF THE ADVANCING FRONT...LEADING TO SCATTERED TO NUMEROUS
SHOWERS AND STORMS ACROSS MUCH OF THE OHIO RIVER VALLEY. ORGANIZED
AREA OF SHOWERS AND STORMS HAS JUST ABOUT CLEARED OUR NORTHEAST
COUNTIES...WITH A LULL SPREADING OVER THE AREA.
HOWEVER...ADDITIONAL ISOLATED SHOWERS AND A FEW STORMS ARE
STARTING OT POP UP IN SOUTH CENTRAL KENTUCKY. THIS ACTIVITY WILL
CONTINUE TO FILL IN AND DEVELOPMENT THROUGH THE EVENING.
HOWEVER...AS INSTABILITY DECREASES WITH SUNSET THIS EVENING...WE
COULD SEE MUCH OF THE ACTIVITY OUT THERE NOW DIE OFF EXCEPT FOR
THE MORE ORGANIZED CLUSTERS OF STORMS. FOR EASTERN
KENTUCKY...THERE DOESN`T APPEAR TO BE ANY ADDITIONAL ORGANIZED
STORMS HEADING OUR WAY...SO IT LOOKS LIKE WE SHOULD SEE A LULL
INTO THE OVERNIGHT HOURS. HOWEVER...COLD FRONT WILL MOVE LATE
TONIGHT AND AROUND DAYBREAK...WITH SHOWERS AND STORMS INCREASING
IN COVERAGE. THIS FRONT WILL CROSS THE AREA TOMORROW
MORNING...BEFORE EXITING BY THURSDAY AFTERNOON. SEVERE THREAT
SHOULD REMAIN LOW GIVEN THE FRONT COMING THROUGH DURING THE
MORNING HOURS WITH LACK OF STRONGER SURFACE INSTABILITY. AS THE
FRONT EXITS BY MID AFTERNOON ON THURSDAY...PRECIPITATION THREAT
WILL END. COOLER AND LESS HUMID CONDITIONS WILL SPREAD IN BEHIND
THE FRONT...SETTING THE STAGE FOR A MUCH COOLER NIGHT FOR THURSDAY
NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 311 PM EDT WED AUG 19 2015
THE WEATHER STARTS OUT FAIRLY BENIGN EARLY FRIDAY MORNING AS A SFC
HIGH PRESSURE BUILDS INTO THE REGION BEHIND A COLD FRONTAL PASSAGE.
THIS WILL ALLOW FOR COOLER...DRIER AIR TO FILTER INTO THE REGION
KEEPING CLOUDS TO A MINIMUM AND DEW POINTS IN THE 50S TO LOWER 60S.
IN FACT...FRIDAY WILL BE A BEAUTIFUL SUMMER DAY WITH HIGHS IN THE
MID TO UPPER 70S AND LOW HUMIDITY.
BY SUNDAY...AN UPPER LEVEL LOW DEVELOPS ALONG THE CANADIAN/US BORDER
MOVING MAINLY EWD. AN ASSOCIATED SFC LOW DEVELOPS PULLING A COLD
FRONT TO ITS SOUTH ACROSS THE CENTRAL U.S. ON MONDAY.
HOWEVER...THESE FEATURES SHOULD STAY WELL TO OUR NORTH AND LIMIT THE
FORCING...AND THE PRECIP...AS THE FRONT MOVES THROUGH EASTERN KY ON
MONDAY.
HIGH PRESSURE WILL BUILD INTO THE REGION ONCE AGAIN AFTER THE
FRONTAL PASSAGE ON MONDAY...ALLOWING FOR COOLER AND DRIER WEATHER TO
END THE PERIOD. TEMPERATURES THROUGHOUT THE EXTENDED WILL BE AT OR
BELOW NORMAL VALUES WITH HIGHS GENERALLY IN THE UPPER 70S AND LOW
80S...AND LOWS IN THE 50S TO LOW 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 315 AM EDT THU AUG 20 2015
CONDITIONS WERE LARGELY VFR AT THE START OF THE PERIOD...WITH MVFR
AT A FEW PLACES. THERE WERE A FEW LIGHT SHOWERS...WITH A GREATER
CONCENTRATION ABOUT TO MOVE IN FROM THE WEST. THESE SHOWERS WERE
AHEAD OF A COLD FRONT WHICH WILL MOVE THROUGH ON THURSDAY MORNING.
A DROP TO MVFR AND LOCALIZED IFR IS EXPECTED OVERNIGHT AS SHOWERS
DEVELOP AND MOVE IN. DRY WEATHER AND VFR SHOULD RETURN FROM NW TO
SE DURING THE COURSE OF THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM...JVM
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
749 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 749 PM EDT FRI AUG 21 2015
DRY AIR MASS WILL LINGER AT THE LOW LEVELS THRU THIS FCST PERIOD...
RESULTING IN VFR CONDITIONS AT KIWD/KCMX/KSAW. ONE ITEM OF NOTE WILL
BE THE THICK SMOKE LAYER WELL ALOFT THAT HAS ORIGINATED FROM THE
FOREST FIRES IN THE PACIFIC NW. OTHERWISE...TIGHTENING PRES GRADIENT
BTWN HIGH PRES OVER THE LOWER GREAT LAKES VCNTY AND A VIGOROUS LOW
PRES SYSTEM DEVELOPING OVER THE DAKOTAS WILL RESULT IN LLWS TONIGHT
AT KIWD/KSAW AS NOCTURNAL INVERSION DEVELOPS. WITH ONSET OF DAYTIME
HEATING SAT...WINDS WILL BECOME GUSTY FROM THE S AT ALL TERMINALS.
HIGHEST GUSTS TO AROUND 30KT WILL OCCUR SAT AFTN AT KIWD/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...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
752 PM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 748 PM CDT FRI AUG 21 2015
UPDATED TO INCLUDE 00Z AVIATION DISCUSSION BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 408 PM CDT FRI AUG 21 2015
ACCAS EARLIER THIS MORNING EVOLVED ENE AND A FEW SHOWERS DEVELOPED
THROUGH THE SOUTH METRO AND HAVE SINCE PUSHED INTO WESTERN
WISCONSIN. THESE WILL CONTINUE EAST OVER THE NEXT 2-3 HOURS AND
FIZZLE. THE SMOKE WE`VE SEEN OVERSPREAD THE AREA WILL LIKELY REMAIN
IN PLACE THROUGH THE REST OF THE EVENING...AND POSSIBLY LONGER.
SOME OF IT MAY GET WRAPPED UP IN THE CIRCULATION OF THE APPROACHING
LOW PRESSURE SYSTEM...WHICH MEANS WE COULD SEE BOUTS OF IT THROUGH
SUNDAY.
CONFIDENCE IS INCREASING IN THE FORECAST FOR POTENTIALLY SEVERE
THUNDERSTORMS TOMORROW. THE SHORT TERM PERIOD ENDS AT 7PM
SATURDAY...SO FOR DETAILS ABOUT THE FORECAST FOR SATURDAY NIGHT AND
BEYOND...SEE THE LONG TERM DISCUSSION BELOW.
CURRENTLY...AN UPPER TROUGH DIGGING INTO THE PACIFIC NORTHWEST IS
DEVELOPING A LOW PRESSURE SYSTEM ACROSS WYOMING/MONTANA. THIS
VIGOROUS WAVE WILL DIG FURTHER TONIGHT AS THE LOW PUSHES EAST INTO
THE WESTERN DAKOTAS AND DEEPENS TO AROUND 994-996MB...AN ANOMALOUSLY
DEEP LOW PRESSURE SYSTEM FOR THIS TIME OF YEAR. THE LOW TRACK IS
EXPECTED TO GO FROM NORTHWESTERN SOUTH DAKOTA THROUGH NORTHWESTERN MN
BY LATE TOMORROW AFTERNOON.
AS THIS SYSTEM APPROACHES EARLY TOMORROW MORNING...STRONG THETA-E
ADVECTION IN SOUTHWESTERLY LOW LEVEL FLOW MAY PRODUCE ISOLATED
SHOWERS THROUGH THE MORNING IF THE MOISTURE INFLOW AND LIFT CAN
OVERCOME THE DRY WARM AIR ASSOCIATED WITH THE BUILDING CAP WELL OUT
AHEAD OF THE COLD FRONT. INTRODUCED ISOLATED SHOWERS AS CAMS
INDICATE THIS BROAD ASCENT AND COULD ACHIEVE SATURATION AND LEAD TO
SOME SHOWERS. OTHERWISE...SIMPLY A SHARP INCREASE IN CLOUD COVER IS
EXPECTED. BY MID MORNING....THE COLD FRONT WILL STILL BE IN THE
DAKOTAS...BUT THE DEEP LOW PUSHING CLOSER WILL TIGHTEN THE PRESSURE
GRADIENT ACROSS THE AREA AND STRONG SOUTHERLY WINDS ARE STILL
EXPECTED. SUSTAINED WIND SPEEDS OF 20-30 MPH WITH GUSTS NEAR 35 MPH
POSSIBLE.
BY THE AFTERNOON...THE FRONT WILL PUSH INTO WESTERN MN...WITH 2000-
3000 J/KG OF SBCAPE AHEAD OF THE FRONT. LOW LEVEL SHEAR IS
STRONG...WITH A MID AFTERNOON LOW LEVEL JET PRODUCING 850-900MB
WINDS AROUND 50 KNOTS...AND EFFICIENT MOISTURE TRANSPORT. SURFACE
DEW POINTS WILL QUICKLY APPROACH 70 DEGREES AHEAD OF THE FRONT. THE
UPPER LEVEL DIVERGENCE COUPLED WITH LOW LEVEL WAA AND MOISTURE
ADVECTION IN ADDITION TO THE VIGOROUS WAVE AN PV BOOT ALL INDICATE
THE STRONG BROAD ASCENT NEEDED TO EVENTUALLY OVERCOME THE CAP THAT
WILL DEVELOP IN THE MORNING WILL ALLOW POTENTIALLY STRONG
THUNDERSTORMS TO DEVELOP BY MID AFTERNOON IN WESTERN MN. WITH THE
LARGE SCALE STRONG ASCENT...THE STORMS SHOULD QUICKLY CONGEAL INTO A
LINE OF THUNDERSTORMS AS THEY APPROACH THE TWIN CITIES METRO.
TIMING HAS BEEN CONSISTENT WITH THE CAMS...SO STILL EXPECTING THE
STORMS TO REACH THE FAR WEST METRO AROUND 5-6PM. ONCE THEY DO
CONGEAL INTO A LINE...DAMAGING WIND WILL BE THE PRIMARY THREAT...BUT
SEVERE HAIL AND A FEW TORNADOES ARE POSSIBLE....ESPECIALLY EARLIER
WHEN DISCRETE CELLS CAN GET GOING INITIALLY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 408 PM CDT FRI AUG 21 2015
BY 00Z THE LINE OF SHOWERS AND THUNDERSTORMS SHOULD BE NEAR THE
INTERSTATE 35 CORRIDOR...AND BY 06Z EAST OF THE AREA. THE SEVERE
THREAT LESSENS WITH EASTWARD PROGRESSION INTO WI...BUT STILL
ADEQUATE INSTABILITY/SHEAR TO WARRANT A SLIGHT RISK INTO THE
EVENING HOURS.
COULD SEE SOME WRAP-AROUND SHOWERS AS FAR SOUTH AS THE INTERSTATE
94 CORRIDOR OVERNIGHT AND SUNDAY AS THE NEGATIVELY TILTED TROUGH
LIFTS INTO NORTHWESTERN ONTARIO. A TIGHT SFC PRESSURE GRADIENT
WILL ALSO RESULT...LEADING TO GUSTY WESTERLY WINDS ON SUNDAY. COOL
TEMPERATURES WILL ALSO RESULT...WITH HIGHS IN THE 60S ON SUNDAY
AND MONDAY...WHICH IS 10 TO 15 DEGREES BELOW NORMAL.
WESTERN MID LEVEL RIDGING GRADUALLY BUILDS TOWARD THE CENTRAL
CONUS DURING THE UPCOMING WEEK. TEMPERATURES WILL SLOWLY
MODERATE...ON AVERAGE 2-3 DEGREES PER DAY. THIS WILL MEAN WE WILL
GET BACK TO NEAR NORMAL TEMPERATURES ON THURSDAY...WHEN HIGHS WILL
RANGE FROM 75-80 DEGREES.
REALLY WILL NOT SEE MUCH IN THE WAY OF PRECIPITATION AGAIN UNTIL
POSSIBLY LATE THURSDAY...WHEN FLATTENING OF THE MID LEVEL RIDGE
OCCURS AND MID LEVEL ENERGY MOVES OVERHEAD IN CONJUNCTION WITH THE
ARRIVAL OF A WEAK SURFACE TROUGH. HAVE INCLUDED 30-40 POPS IN THE
THURSDAY-FRIDAY TIME FRAME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 748 PM CDT FRI AUG 21 2015
FORECAST THOUGHTS HAVEN/T CHANGED MUCH FROM EARLIER TAFS. DID BACK
OFF A BIT ON INTRODUCTION OF SUB 10K AGL CEILINGS TO DELAY BASED
ON LATEST SATELLITE IMAGERY AND RAP OUTPUT. HOWEVER... STILL
EXPECT SOME VFR CEILINGS TO WORK INTO THE AREA ON SATURDAY PRIOR
TO CHANCES FOR PCPN LATER IN THE DAY. ALSO SLIGHTLY DELAYED
CHANCES FOR SHRA/TSRA GIVEN LATEST HIGH RESOLUTION MODEL OUTPUT
AND EXPECTED FROPA TIMING. INCREASED WIND GUSTS SLIGHTLY DURING
THE DAY GIVEN EXPECTED DEGREE OF MIXING AND STRONG WINDS IN THE
FORECAST PROFILES.
KMSP...MAIN CONCERNS ARE STRONG SOUTHERLY WIND GUSTS EXPECTED FOR
MUCH OF THE DAY PRIOR TO FROPA IN THE EVENING. SHRA/TSRA FOR A 2
HOUR OR SO WINDOW LOOKS PRETTY CERTAIN... WITH SOME QUESTION
REMAINING ON THE EXACT TIMING... BUT BEST CHANCE STILL LOOKS TO BE
AROUND OR SHORTLY AFTER 00Z.
/OUTLOOK FOR KMSP/
SAT OVERNIGHT...VFR. W WINDS 10 TO 20 KT.
SUN...MVFR EARLY THEN VFR. CHC -SHRA. WIND W AT 15G25KT
MON...VFR. WIND NW AT 15G25KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
UPDATE...
SHORT TERM...SPD
LONG TERM...LS
AVIATION...
AREA FORECAST DISCUSSION
NWS DULUTH MN
331 PM CDT THU AUG 20 2015
.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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 330 PM CDT THU AUG 20 2015
VFR CONDTIONS THIS AFTERNOON AT THE BRD/HIB/INL SITES. DLH TAF WILL
BE MVFR IMPROVING TO VFR BY LATE AFTERNOON. HYR TAF WILL STAY MVFR-
IFR THROUGH 00Z WHEN IT WILL IMPROVE TO VFR. OVERNIGHT...FOG WILL
LIKELY FORM DUE TO THE LIGHT WINDS/CLEAR SKIES/MOISTURE FROM THE
PAST DAYS RAINS AND WILL LOWER CONDTIONS TO MVFR-IFR THROUGH
12Z. CONDITIONS WILL IMPROVE TO VFR AT ALL SITES BY MID-MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 51 78 62 79 / 0 0 20 40
INL 47 82 60 80 / 20 20 20 70
BRD 52 82 64 81 / 0 0 20 70
HYR 48 79 62 81 / 0 10 10 10
ASX 47 80 61 84 / 0 0 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ148.
&&
$$
SHORT TERM...JJM
LONG TERM...STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1042 PM CDT FRI AUG 21 2015
.UPDATE:
ISSUED AT 934 PM CDT FRI AUG 21 2015
CLOUDS OVER WESTERN MISSOURI WILL GRADUALLY SPREAD EAST LATER THIS
EVENING AND OVERNIGHT AHEAD OF A WEAK SHORTWAVE TROUGH CURRENTLY
OVER NORTHEAST KANSAS. STILL EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP OVER THE MISSOURI COUNTIES AFTER MIDNIGHT
AS THE LATEST RUNS OF THE RAP CONTINUE TO SHOW DECENT LOW LEVEL MOISTURE
CONVERGENCE DEVELOPING AHEAD OF THIS SHORTWAVE. THIS IS ALSO
SUPPORTED BY THE LATEST RUNS OF THE CAMS WHICH ALSO SHOW
CONVECTION DEVELOPING OVERNIGHT OVER THE WESTERN HALF OF THE CWA.
OTHERWISE...GOING LOW TEMPERATURES STILL LOOK GOOD.
BRITT
&&
.SHORT TERM: (THROUGH LATE TONIGHT)
ISSUED AT 258 PM CDT FRI AUG 21 2015
AN APPROACHING SHORTWAVE FROM THE PLAINS COUPLED WITH SOUTH-
SOUTHWESTERLY WINDS BRINGING INCREASING LOW LEVEL MOISTURE INTO
OUR AREA WILL LEAD TO CONVECTION DEVELOPING AND MOVING FROM
SOUTHWEST MO INTO CENTRAL AND SOUTHEAST MO LATE TONIGHT...WEST
AND SOUTHWEST OF STL. LOW TEMPERATURES TONIGHT SHOULD BE A LITTLE
WARMER THAN THE PREVIOUS TWO NIGHTS DUE TO INCREASED CLOUD COVER
AND SOUTHEASTERLY SURFACE WINDS ON THE WESTERN PERIPHERY OF THE
SURFACE RIDGE OVER THE OHIO VALLEY REGION.
GKS
.LONG TERM: (SATURDAY THROUGH NEXT FRIDAY)
ISSUED AT 258 PM CDT FRI AUG 21 2015
CONVECTION WILL CONTINUE SATURDAY MORNING INTO THE AFTERNOON
MAINLY ACROSS CENTRAL AND SOUTHEAST MO...ALONG AND WEST OF THE
MISSISSIPPI RIVER. IT APPEARS THAT THE CONVECTION WILL DISSIPATE
OR AT LEAST WEAKEN AS IT MOVES INTO SOUTHWEST IL AND ENCOUNTERS
SLIGHTLY LESS LOW LEVEL MOISTURE AND INSTABILITY. THERE MAY BE A
BRIEF BREAK IN THE PRECIPITATION THREAT DURING THE LATE AFTERNOON
AND EARLY EVENING HOURS...THEN A LARGE AREA OF CONVECTION WILL
DROP SOUTHEASTWARD INTO OUR AREA FROM THE PLAINS LATE SATURDAY
EVENING AND OVERNIGHT. A DEEP UPPER LEVEL TROUGH...LOW WILL MOVE
EASTWARD THROUGH THE NORTHERN PLAINS AND SEND A COLD FRONT
SOUTHEASTWARD THROUGH OUR FORECAST AREA LATE SATURDAY NIGHT AND
SUNDAY MORNING. THE GFS MODEL IS THE FASTEST WITH THE
FRONT...WHILE THE ECMWF IS A LITTLE SLOWER...AND THE NAM IS THE
SLOWEST. THE CONVECTION WILL LIKELY WEAKEN SOME IS IT DROPS
SOUTHEASTWARD THROUGH OUR AREA LATE SATURDAY NIGHT INTO SUNDAY
MORNING WITH THE MODELS DEPICTING DECREASING QPF. EVEN IF THE
SLOWER PROGRESSION OF THE FRONT WOULD VERIFY IT APPEARS THAT THE
SHOWERS AND STORMS WILL BE CONFINED TO SOUTHEAST MO AND SOUTHWEST
IL BY SUNDAY AFTERNOON AS COOLER AND DRIER AIR FILTERS INTO
NORTHEAST AND CENTRAL MO AS WELL AS WEST CENTRAL ILLINOIS SUNDAY
AFTERNOON AFTER THE PASSAGE OF THE COLD FRONT. THE PRECIPITATION
SHOULD COMPLETELY SHIFT SOUTHEAST OF OUR FORECAST AREA BY SUNDAY
EVENING AS THE UPPER LEVEL LOW MOVES EASTWARD THROUGH THE GREAT
LAKES REGION AND A LARGE SURFACE RIDGE BUILDS EASTWARD INTO MO
BEHIND THE COLD FRONT. UNSEASONABLY COOL CONDITIONS ALONG WITH LOW
HUMIDITIES ARE EXPECTED SUNDAY NIGHT INTO THE FIRST PORTION OF THE
NEXT WORK WEEK WITH NORTHWEST MID-UPPER LEVEL FLOW AND AS A LARGE
SURFACE RIDGE MOVES ONLY SLOWLY EASTWARD THROUGH THE REGION.
SHOULD EVENTUALLY SEE A GRADUAL WARMING TREND FOR THE LATTER
PORTION OF THE WORK WEEK AS UPPER LEVEL HEIGHTS BEGIN TO RISE AND
THE SURFACE WINDS BECOME SOUTHERLY AS THE SURFACE RIDGE FINALLY
SHIFTS EAST OF OUR AREA. THE CHANCE OF PRECIPITATION MAY RETURN
TO OUR AREA BY THE END OF THE EXTENDED FORECAST AS MOISTURE MOVES
BACK INTO OUR AREA WITH THE POTENTIAL FOR NORTHWEST FLOW
SHORTWAVES AND ANOTHER COLD FRONT DROPPING SOUTHEASTWARD INTO THE
REGION.
GKS
&&
.AVIATION: (FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1034 PM CDT FRI AUG 21 2015
SURFACE RIDGE CONTINUES TO MOVE OFF TO THE EAST WITH LOW LEVEL
MOISTURE ON THE INCREASE. SC HAS DEVELOPED OVER SOUTHWESTERN
MISSOURI AND CONTINUES TO ADVECT NORTHWARD TOWARDS FORECAST AREA.
LOW END VFR DECK TO MOVE INTO KCOU BY 06Z SATURDAY THEN INTO REST
OF TAF SITES TOWARDS DAYBREAK. AS FOR PRECIPITATION CHANCES, WILL
SEE ACTIVITY DEVELOP OVER CENTRAL MO AND TRACK TO THE EAST. STILL
HARD TO PIN DOWN COVERAGE AND IF IT WILL MAKE IT INTO STL METRO
AREA, SO KEPT VCTS MENTION FOR NOW. ACTIVITY TO DIMINISH BY MID
MORNING SATURDAY. OTHERWISE, WINDS TO PERSIST FROM THE SOUTHEAST
TO SOUTH.
SPECIFICS FOR KSTL:
SURFACE RIDGE CONTINUES TO MOVE OFF TO THE EAST WITH LOW LEVEL
MOISTURE ON THE INCREASE. SC HAS DEVELOPED OVER SOUTHWESTERN
MISSOURI AND CONTINUES TO ADVECT NORTHWARD TOWARDS FORECAST AREA.
LOW END VFR DECK TO MOVE INTO KSTL BY 10Z SATURDAY. AS FOR
PRECIPITATION CHANCES, WILL SEE ACTIVITY DEVELOP OVER CENTRAL MO
AND TRACK TO THE EAST. STILL HARD TO PIN DOWN COVERAGE AND IF IT
WILL MAKE IT INTO STL METRO AREA, SO KEPT VCTS MENTION FOR NOW
AFTER 14Z SATURDAY. ACTIVITY TO DIMINISH BY 18Z SATURDAY.
OTHERWISE, WINDS TO PERSIST FROM THE SOUTHEAST TO SOUTH.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
935 PM CDT FRI AUG 21 2015
.UPDATE:
ISSUED AT 934 PM CDT FRI AUG 21 2015
CLOUDS OVER WESTERN MISSOURI WILL GRADUALLY SPREAD EAST LATER THIS
EVENING AND OVERNIGHT AHEAD OF A WEAK SHORTWAVE TROUGH CURRENTLY
OVER NORTHEAST KANSAS. STILL EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP OVER THE MISSOURI COUNTIES AFTER MIDNIGHT
AS THE LATEST RUNS OF THE RAP CONTINUE TO SHOW DECENT LOW LEVEL MOISTURE
CONVERGENCE DEVELOPING AHEAD OF THIS SHORTWAVE. THIS IS ALSO
SUPPORTED BY THE LATEST RUNS OF THE CAMS WHICH ALSO SHOW
CONVECTION DEVELOPING OVERNIGHT OVER THE WESTERN HALF OF THE CWA.
OTHERWISE...GOING LOW TEMPERATURES STILL LOOK GOOD.
BRITT
&&
.SHORT TERM: (THROUGH LATE TONIGHT)
ISSUED AT 258 PM CDT FRI AUG 21 2015
AN APPROACHING SHORTWAVE FROM THE PLAINS COUPLED WITH SOUTH-
SOUTHWESTERLY WINDS BRINGING INCREASING LOW LEVEL MOISTURE INTO
OUR AREA WILL LEAD TO CONVECTION DEVELOPING AND MOVING FROM
SOUTHWEST MO INTO CENTRAL AND SOUTHEAST MO LATE TONIGHT...WEST
AND SOUTHWEST OF STL. LOW TEMPERATURES TONIGHT SHOULD BE A LITTLE
WARMER THAN THE PREVIOUS TWO NIGHTS DUE TO INCREASED CLOUD COVER
AND SOUTHEASTERLY SURFACE WINDS ON THE WESTERN PERIPHERY OF THE
SURFACE RIDGE OVER THE OHIO VALLEY REGION.
GKS
.LONG TERM: (SATURDAY THROUGH NEXT FRIDAY)
ISSUED AT 258 PM CDT FRI AUG 21 2015
CONVECTION WILL CONTINUE SATURDAY MORNING INTO THE AFTERNOON
MAINLY ACROSS CENTRAL AND SOUTHEAST MO...ALONG AND WEST OF THE
MISSISSIPPI RIVER. IT APPEARS THAT THE CONVECTION WILL DISSIPATE
OR AT LEAST WEAKEN AS IT MOVES INTO SOUTHWEST IL AND ENCOUNTERS
SLIGHTLY LESS LOW LEVEL MOISTURE AND INSTABILITY. THERE MAY BE A
BRIEF BREAK IN THE PRECIPITATION THREAT DURING THE LATE AFTERNOON
AND EARLY EVENING HOURS...THEN A LARGE AREA OF CONVECTION WILL
DROP SOUTHEASTWARD INTO OUR AREA FROM THE PLAINS LATE SATURDAY
EVENING AND OVERNIGHT. A DEEP UPPER LEVEL TROUGH...LOW WILL MOVE
EASTWARD THROUGH THE NORTHERN PLAINS AND SEND A COLD FRONT
SOUTHEASTWARD THROUGH OUR FORECAST AREA LATE SATURDAY NIGHT AND
SUNDAY MORNING. THE GFS MODEL IS THE FASTEST WITH THE
FRONT...WHILE THE ECMWF IS A LITTLE SLOWER...AND THE NAM IS THE
SLOWEST. THE CONVECTION WILL LIKELY WEAKEN SOME IS IT DROPS
SOUTHEASTWARD THROUGH OUR AREA LATE SATURDAY NIGHT INTO SUNDAY
MORNING WITH THE MODELS DEPICTING DECREASING QPF. EVEN IF THE
SLOWER PROGRESSION OF THE FRONT WOULD VERIFY IT APPEARS THAT THE
SHOWERS AND STORMS WILL BE CONFINED TO SOUTHEAST MO AND SOUTHWEST
IL BY SUNDAY AFTERNOON AS COOLER AND DRIER AIR FILTERS INTO
NORTHEAST AND CENTRAL MO AS WELL AS WEST CENTRAL ILLINOIS SUNDAY
AFTERNOON AFTER THE PASSAGE OF THE COLD FRONT. THE PRECIPITATION
SHOULD COMPLETELY SHIFT SOUTHEAST OF OUR FORECAST AREA BY SUNDAY
EVENING AS THE UPPER LEVEL LOW MOVES EASTWARD THROUGH THE GREAT
LAKES REGION AND A LARGE SURFACE RIDGE BUILDS EASTWARD INTO MO
BEHIND THE COLD FRONT. UNSEASONABLY COOL CONDITIONS ALONG WITH LOW
HUMIDITIES ARE EXPECTED SUNDAY NIGHT INTO THE FIRST PORTION OF THE
NEXT WORK WEEK WITH NORTHWEST MID-UPPER LEVEL FLOW AND AS A LARGE
SURFACE RIDGE MOVES ONLY SLOWLY EASTWARD THROUGH THE REGION.
SHOULD EVENTUALLY SEE A GRADUAL WARMING TREND FOR THE LATTER
PORTION OF THE WORK WEEK AS UPPER LEVEL HEIGHTS BEGIN TO RISE AND
THE SURFACE WINDS BECOME SOUTHERLY AS THE SURFACE RIDGE FINALLY
SHIFTS EAST OF OUR AREA. THE CHANCE OF PRECIPITATION MAY RETURN
TO OUR AREA BY THE END OF THE EXTENDED FORECAST AS MOISTURE MOVES
BACK INTO OUR AREA WITH THE POTENTIAL FOR NORTHWEST FLOW
SHORTWAVES AND ANOTHER COLD FRONT DROPPING SOUTHEASTWARD INTO THE
REGION.
GKS
&&
.AVIATION: (FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 730 PM CDT FRI AUG 21 2015
MOSTLY CLEAR SKIES WITH WINDS BECOMING LIGHT AND
SOUTHEASTERLY/EASTERLY THIS EVENING. THEN AS NEXT SHORTWAVE
APPROACHES REGION LATE TONIGHT, WILL SEE AN INCREASE IN MOISTURE
WITH WARM FRONT DEVELOPING OVER SOUTHERN PORTIONS OF FORECAST
AREA. SOME SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP OVER
SOUTHWEST MO AND TRACK TO THE EAST AND NORTHEAST, SO KEPT VCTS
MENTION AT KCOU AFTER 09Z SATURDAY. OTHERWISE, CIGS TO LOWER TO
LOW END VFR THROUGH REST OF TAF PERIOD. ACTIVITY THAT DOES DEVELOP
SHOULD REMAIN SOUTH OF KUIN AS WELL AS STL METRO AREA, SO NO
MENTION IN THESE TAFS FOR NOW. AS FOR THE LIGHT WINDS, TO VEER TO
THE SOUTH AND PICKUP TO AROUND 10KTS BY MID MORNING ON SATURDAY.
SPECIFICS FOR KSTL:
MOSTLY CLEAR SKIES WITH WINDS BECOMING LIGHT AND
EASTERLY THIS EVENING. THEN AS NEXT SHORTWAVE APPROACHES REGION
LATE TONIGHT, WILL SEE AN INCREASE IN MOISTURE WITH WARM FRONT
DEVELOPING OVER SOUTHERN PORTIONS OF FORECAST AREA. SOME SHOWERS
AND THUNDERSTORMS EXPECTED TO DEVELOP OVER SOUTHWEST MO AND TRACK
TO THE EAST AND NORTHEAST, BUT SHOULD REMAIN SOUTH AND SOUTHWEST
OF METRO AREA. OTHERWISE, CIGS TO LOWER TO LOW END VFR THROUGH
REST OF TAF PERIOD. AS FOR THE LIGHT WINDS, TO VEER TO THE SOUTH
AND PICKUP TO AROUND 10KTS BY 16Z SATURDAY.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1226 AM CDT THU AUG 20 2015
.SHORT TERM...(This Evening through Friday Night)
Issued at 400 PM CDT WED AUG 19 2015
Can`t beat this weather...October in mid August. Better enjoy it
while it lasts.
Deep upper trough extending from MN through eastern KS into OK will
continue tracking east tonight. Water vapor imagery shows a weak
vorticity max dropping down the back side of the trough across
western IA. Widely scattered instability showers have popped as a
result. HRRR trend supports low-end slight chance PoPs over northern
MO until about sunset. Most likely only sprinkles. Otherwise,
heating based stratocu cloud cover from NE into the CWA should
dissipate with loss of daytime heating and leave skies cloud free by
midnight. Could be flirting with record lows tomorrow morning. MCI
record min is 53 and STJ is 48.
Temperatures will rebound, but remain below average on Thursday,
before returning closer to seasonal on Friday. Warming will be the
result of the cooler/drier air being pulled away as the upper trough
moves east vs return flow from a retreating surface high. But even
the warm-up will be pleasant by summer standards as dewpoints will
remain in the 50s on Thursday and only increase into the lower 60s
on Saturday. Sure beats the upper 60s to lower 70s which occur so
often this time of year.
Will leave the forecast rain-free through Friday except for a token
slight chance PoP over far northwest MO late Thursday night.
Rain chances begin to ramp up late Friday night into Saturday
morning as stronger isentropic ascent tied to increasing low-level
moisture and development of the nocturnal low-level jet.
.LONG TERM...(Saturday through Wednesday)
Issued at 400 PM CDT WED AUG 19 2015
The GFS, European, and Canadian models are all in good agreement
that this weekend will see a pattern very similar to the pattern
that moved through the area the past couple days. The models depict
an upper level trough will develop and slide east over the northern
states through the weekend. An associated cold front will advance
across the Central Plains ahead of the trough. The models show the
best chance for storms will be Saturday night into Sunday as the
upper level trough moves over the Dakotas and the cold front moves
through the forecast area. Initially, convection will occur across
MN and IA earlier Saturday evening before spreading further south
into the forecast area as the cold front interacts with increasing
moisture ahead of and along the front. Severe potential would be
limited if showers or cloud cover linger throughout the day on
Saturday as these could restrict surface heating and convection
later in the evening. Just like today, showers could linger on
Sunday morning after the passage of the cold front. Also,
temperatures will be lower than normal for August on Sunday into
Monday, and dry conditions will prevail after the lingering showers
dissipate on Sunday. Temperatures gradually increase throughout the
early part of the work week as upper level high pressure slowly
builds over the Plains.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1225 AM CDT THU AUG 20 2015
VFR conditions are expected to dominate the terminals for the next
24 hours. Only issue there might be a bit of steam fog from the
Missouri River for the KSTJ terminal around sunrise. Otherwise,
expect winds to remain under 10 knots from the southwest.
&&
.CLIMATE...
Issued at 400 PM CDT WED AUG 19 2015
Record low temperature/date for August 19th...
Kansas City (MCI) 53/1950
St. Joseph (STJ) 48/1981
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...HEC
AVIATION...Cutter
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
944 PM MDT FRI AUG 21 2015
.UPDATE...
CONVECTION WANING AND SHORT TERM MODELS INDICATE THIS TREND WILL
CONTINUE...THEREFORE TRIMMED BACK EVENING POPS AND REMOVED MENTION
OF STRONG STORMS IN THE FAR EASTERN PLAINS. UPDATED ZFP ALREADY
TRANSMITTED.
&&
.PREV DISCUSSION...609 PM MDT FRI AUG 21 2015...
.AVIATION...
00Z TAF CYCLE
OUTFLOW BOUNDARY COLLISIONS ARE GOING TO BE THE MAIN DRIVER OF NEW
CONVECTION THRU THE EVENING. A FEW STRONG TO SEVERE STORMS ARE
POSSIBLE NEAR THE TX BORDER WITH LARGE HAIL AND DAMAGING WIND
GUSTS. STORMS ACROSS NORTHERN NM SHOULD START TO DIMINISH WITH
SUNSET...THOUGH STORMS ACROSS WEST CENTRAL NM MAY PERSIST WELL
INTO THE EVE. ANOTHER ROUND OF SHRA/TSRA IS EXPECTED ON
SAT...FAVORING THE SOUTHERN TIER OF THE CWA ONCE AGAIN. LOCALLY
HEAVY RAIN...SMALL HAIL AND GUSTY WINDS WILL BE THE MAIN THREATS.
34
&&
.PREV DISCUSSION...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
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
609 PM MDT FRI AUG 21 2015
.AVIATION...
00Z TAF CYCLE
OUTFLOW BOUNDARY COLLISIONS ARE GOING TO BE THE MAIN DRIVER OF NEW
CONVECTION THRU THE EVENING. A FEW STRONG TO SEVERE STORMS ARE
POSSIBLE NEAR THE TX BORDER WITH LARGE HAIL AND DAMAGING WIND
GUSTS. STORMS ACROSS NORTHERN NM SHOULD START TO DIMINISH WITH
SUNSET...THOUGH STORMS ACROSS WEST CENTRAL NM MAY PERSIST WELL
INTO THE EVE. ANOTHER ROUND OF SHRA/TSRA IS EXPECTED ON
SAT...FAVORING THE SOUTHERN TIER OF THE CWA ONCE AGAIN. LOCALLY
HEAVY RAIN...SMALL HAIL AND GUSTY WINDS WILL BE THE MAIN THREATS.
34
&&
.PREV DISCUSSION...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
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1030 AM EDT THU AUG 20 2015
.SYNOPSIS...
A STRONG AND SLOW MOVING COLD FRONT WILL CROSS THE AREA TODAY WHICH
WILL BRING SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN AND POSSIBLY
GUSTY WINDS. COOLER AND DRIER AIR WILL RETURN BEHIND THE COLD FRONT
BRINGING SEASONABLE AND PLEASANT WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1000 AM... A LINE OF SHOWERS AND THUNDERSTORMS HAS DEVELOPED
ALONG OF THE FRONT ACROSS NORTHWESTERN PENNSYLVANIA NORTHWARD TO
SOUTHERN ONTARIO AND IS HEADING TOWARD WESTERN NEW YORK. THIS IS
FEATURE IS WELL CAPTURED BY THE HRRR AND IS FORECAST TO MOVE ACROSS
THE NIAGARA FRONTIER AND WESTERN NEW YORK THROUGH MIDDAY AND THE
AFTERNOON.
WITH THE RISK OF HEAVY RAIN...THE THREAT FOR FLASH FLOODING
CONTINUES ACROSS THE AREA. PWATS FROM 00Z SOUNDINGS AT DTX/ILN RUN
1.75 TO 2 INCHES...WITH A 35KT 850MB FLOW SET TO ADVECT THIS WARM
AND MOIST AIRMASS INTO OUR REGION TODAY. THE TIMING OF THE FRONTAL
PASSAGE IS ALSO FAVORABLE SINCE IT WILL ALLOW FOR DESTABILIZATION
FROM DAYTIME HEATING AHEAD OF THE FRONT...ESPECIALLY IN EASTERN
PORTIONS OF THE CWA. 00Z RUNS OF THE NAM/RGEM/GFS CAPTURE THESE
TRENDS WITH FORECAST WIND FIELDS SUGGESTING THE POTENTIAL FOR
TRAINING CELLS. THE AREA OF GREATEST CONCERN IS EASTERN PORTIONS OF
THE CWA WHERE THERE WILL BE MORE TIME FOR THE ATMOSPHERE TO
DESTABILIZE AND WHERE STORMS MAY DEVELOP ACROSS SOUTH-CENTRAL NEW
YORK AND INTERSECT THE SLOW MOVING FRONT EAST OR SOUTHEAST OF LAKE
ONTARIO. A CONSENSUS OF HIGH RESOLUTION GUIDANCE (4KM OR LESS) KEYS
ON THIS AREA...AND OTHER GUIDANCE SEEMS TO SUPPORT THIS IDEA. THERE
STILL IS A POTENTIAL FOR FLASH FLOODING ELSEWHERE SO THE UPDATE WILL
KEEP THE FLASH FLOOD WATCH IN EFFECT...BUT FEEL THE AREA MOST LIKELY
TO SEE THE GREATEST RAINFALL EXTENDS FROM WAYNE TO LEWIS COUNTIES.
IT IS ALSO WORTH NOTING THAT FFG IS FAIRLY HIGH IN MANY AREAS AND
EXACTLY WHERE HEAVY RAIN FALLS WILL PLAY A ROLE IN WHERE FLASH
FLOODING OCCURS. URBAN AREAS AND AREAS WITH STEEP TERRAIN TEND TO BE
MOST VULNERABLE.
A SECONDARY CONCERN IS TODAY IS THE POTENTIAL FOR SEVERE WEATHER.
FORECAST WIND PROFILES SUGGEST A FAIR AMOUNT OF WIND SHEAR AHEAD OF
THE FRONT...PRIMARILY UNIDIRECTIONAL SPEED SHEAR BELOW 850MB. CAPE
WILL BE LIMITED...GENERALLY ONLY 500 J/KG...BUT SOUNDINGS ARE VERY
MOIST WITH A TALL AND SKINNY CAPE. THIS MAY PRODUCE SOME STRONGER
STORMS WITH WINDS THE PRIMARY THREAT. LCLS WILL BE LOW AND
DIRECTIONAL SHEAR MAY BE LOCALLY ENHANCED NEAR EASTERN LAKE ONTARIO
SO EVEN AN ISOLATED TORNADO CANNOT BE RULED OUT IF STRONGER STORMS
DO DEVELOP.
OTHERWISE...THE FORECAST WILL USE CONSENSUS TIMING WITH HIGH
CONFIDENCE IN MEASURABLE PRECIPITATION DUE TO THE FOCUS PROVIDED
BY THE FRONTAL BOUNDARY. SHOWERS AND THUNDERSTORMS WILL LINGER
EAST OF LAKE ONTARIO INTO THE EVENING HOURS. TEMPERATURES WILL BE
ABOVE NORMAL AGAIN TODAY...ESPECIALLY IN EASTERN PORTIONS OF THE
CWA DUE THE THE LATER FROPA IN THESE AREAS.
MUCH COOLER AIR WILL MOVE INTO THE REGION TONIGHT WITH TEMPERATURES
FALLING INTO THE MID 50S TO LOWER 60S BY DAYBREAK. THE COMBINATION
OF A SHORTWAVE AND COOLER TEMPERATURES ALOFT MAY BE JUST ENOUGH
FOR SOME LAKE ENHANCED CLOUDS OR SHOWERS E AND NE OF THE LAKES
LATE TONIGHT. OTHERWISE...EXPECT CLEARING SKIES BEHIND THE FRONT
WITH SOME PATCHY RADIATION FOG POSSIBLE WHERE WINDS DROP OFF.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
NO CHANGES TO CURRENT FORECAST. PREVIOUS DISCUSSION...
HIGH PRESSURE WILL DOMINATE THE FORECAST INTO THIS WEEKEND WITH DRY
WEATHER AND CONSIDERABLY MORE COMFORTABLE TEMPERATURES AND HUMIDITY
LEVELS ACROSS WESTERN AND CENTRAL NEW YORK. MODELS SHOW THIS SURFACE
HIGH QUICKLY BUILDING IN BEHIND THE COLD FRONT DEPARTING ACROSS NEW
ENGLAND ON FRIDAY. THE ONLY EXCEPTION TO THE DRY CONDITIONS MAY BE
FRIDAY MORNING ON THE IMMEDIATE HEELS OF THE COLD FRONT WITH A
CHANCE FOR SOME LIMITED LAKE EFFECT SHOWERS EAST OF LAKES ERIE AND
ONTARIO. 850MB TEMPERATURES ACROSS THE LAKES ARE FORECAST TO DIP
BRIEFLY DOWN TO OR SLIGHTLY BELOW +8 TO +10C WHICH WOULD SUPPORT SOME
LAKE INDUCED INSTABILITY. MOISTURE IS FORECAST TO BE VERY LIMITED
WITH SOUNDINGS SHOWING VERY DRY AIR ABOVE 5KFT. THERE MAY BE ONLY
ENOUGH MOISTURE FOR LAKE EFFECT CLOUDS EAST OF THE LAKES WITH
SCATTERED DIURNAL CUMULUS DEVELOPING WELL INLAND OF THE LAKES.
THE ARRIVAL OF COOLER AIR ALOFT BEHIND THE COLD FRONT WILL KEEP HIGH
TEMPERATURES LIMITED TO THE LOW TO MID 70S FRIDAY THEN MID TO UPPER
70S SATURDAY AS 850MB TEMPS CLIMB BACK ABOVE +12C. DEWPOINTS IN THE
UPPER 40S TO LOW 50S WILL PROVIDE COMFORTABLE HUMIDITY LEVELS WITH
OVERNIGHT LOWS ALSO DIPPING INTO THE 50S EACH NIGHT WITH UPPER 40S
POSSIBLE ACROSS THE INTERIOR SOUTHERN TIER.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
WHILE FAIR AND DRY WEATHER IS EXPECTED TO LINGER INTO
SUNDAY...FORECAST MODELS INCLUDING THE GEFS ENSEMBLES SHOW A
SLIGHTLY ANOMALOUS 500MB TROUGH DIPPING ACROSS THE GREAT LAKES
REGION EARLY NEXT WEEK. THIS TROUGH LOOKS TO BE LED IN BY A WEAK
COLD FRONT CROSSING NEW YORK MONDAY FOLLOWED BY SEASONABLY COOL
TEMPERATURES TUESDAY AND WEDNESDAY.
A CHANCE OF SHOWERS AND THUNDERSTORMS HAS BEEN FEATURED ALONG THIS
FRONT MONDAY THEN SOME LAKE EFFECT SHOWERS MAY AGAIN BECOME POSSIBLE
MONDAY NIGHT AS 850MB TEMPERATURES DIP BACK INTO THE THE SINGLE
DIGITS OVER THE VERY WARM LAKES. HIGH TEMPERATURES IN THE MID 70S TO
AROUND 80 ON SUNDAY AND MONDAY LOOK TO BE FOLLOWED BY HIGHS CLOSER
TO 70 TUESDAY AND WEDNESDAY. THE 00Z GFS SHOWS SOME SHOWERS MAY BE
POSSIBLE IN THE COOL UNSTABLE AIRMASS TUESDAY BUT HAVE LEFT POPS
AT SLIGHT CHANCE FOR NOW AS THE 00Z ECMWF IS DRIER.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
CONDITIONS WILL DETERIORATE TODAY AS A STRONG UPPER LEVEL TROUGH
AND ASSOCIATED COLD FRONT APPROACHES THE AREA WITH SHOWERS AND
THUNDERSTORMS DEVELOPING AHEAD OF THE FRONT. SHOWERS AND
THUNDERSTORMS SHOULD BE SCATTERED IN NATURE WELL AHEAD OF THE
FRONT...BUT THERE SHOULD BE SOLID LINE THAT MOVES THROUGH LATE
THIS MORNING THROUGH THIS EVENING WHICH WILL PRODUCE PERIODS OF
MVFR/IFR CONDITIONS WHICH WILL SPREAD FROM WEST TO EAST THROUGH
TODAY.
CONDITIONS SHOULD IMPROVE RATHER QUICKLY BEHIND THE FRONT THIS
EVENING...HOWEVER SOME PATCHY IFR FOG IS POSSIBLE IN SOME SPOTS
LATE TONIGHT...WITH THE GREATEST POTENTIAL FOR THIS IN VALLEY
LOCATIONS SUCH AS JHW.
OUTLOOK...
FRIDAY THROUGH SUNDAY...VFR.
MONDAY...VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SOUTHERLY WINDS WILL PICK UP IN ADVANCE OF A COLD FRONT THROUGH THIS
MORNING...AND THEN WINDS WILL SHIFT TO THE SOUTHWEST BEHIND THE
FRONT THIS AFTERNOON AND EVENING. COOLER AIR BEHIND THE FRONT
SHOULD ENHANCE MIXING WITH AIR TEMPERATURES FORECAST TO DROP BELOW
THE LAKE TEMPERATURES. THIS WILL REQUIRE SMALL CRAFT ADVISORIES
FOR MOST OF THE WATERS...PRIMARILY FOR WINDS PRE- FRONTAL...AND
FOR WINDS AND WAVE ACTION BEHIND THE FRONT. THERE WILL ALSO BE
SHOWERS AND THUNDERSTORMS WITH THE FRONT WHICH MAY PRODUCE LOCALLY
HIGHER WINDS/WAVES.
LOOK FOR WINDS AND WAVES TO SUBSIDE FRIDAY AS HIGH PRESSURE MOVES
ACROSS THE LAKES IN THE WAKE OF THE FRONT WITH TRANQUIL WEATHER
LASTING THROUGH THE WEEKEND BEFORE A WEAKER FRONT CROSSES THE REGION
MONDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH LATE
TONIGHT FOR NYZ006>008.
FLASH FLOOD WATCH THROUGH THIS EVENING FOR NYZ001>005-010>014-
019>021-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LEZ020.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LOZ042>045.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL/WCH
SHORT TERM...FRANKLIN/SMITH
LONG TERM...SMITH
AVIATION...APFFEL
MARINE...APFFEL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
143 PM EDT THU AUG 20 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY ACROSS THE AREA TONIGHT INTO FRIDAY
CONTINUING A GOOD CHANCE FOR THUNDERSTORMS. SUNNY AND SEASONABLE
WEATHER IS EXPECTED 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.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM THURSDAY...SCATTERED THUNDERSTORMS APPROACHING
WILLIAMSBURG AND FLORENCE COUNTIES FROM THE WEST AT THIS
TIME...WHILE THE REST OF THE FORECAST AREA REMAINS QUIET...LIKELY
DUE TO EXTENSIVE CLOUD COVER THIS MORNING. FORECAST REMAINS ON
TRACK WITH SCATTERED CONVECTION PROGGED FOR THIS AFTERNOON
EVENING. PREVIOUS DISCUSSION FOLLOWS:
12Z CHS SOUNDING SHOULD BE REPRESENTATIVE OF THE AIRMASS TODAY.
MODIFIED FOR HEATING...EXPECT LI TO -4C AND MLCAPE TO 1400 J/KG.
PRECIPITABLE WATER JUST OVER 2 INCHES WILL COMBINE WITH
DESTABILIZATION THIS AFTERNOON TO PRODUCE AN ENVIRONMENT
SUPPORTIVE OF CONVECTION WITH THE POTENTIAL FOR LOCALLY HEAVY
DOWNPOURS. EXTENSIVE MORNING CLOUD COVER WILL LIMIT THE RATE OF
DESTABILIZATION AND COULD RESULT IN LESS COVERAGE THAN THE CURRENT
FORECAST INDICATES. LATEST HRRR DOES HINT AT THIS AS WELL. MAY
TWEAK THE POPS A BIT AND KEEP THE ENTIRE CWA IN THE 40-50 PERCENT
RANGE...BUT WILL ALSO HAVE TO WATCH A WEAKENING 500 MB SHORTWAVE
MOVING ACROSS UPSTATE SC THIS MORNING WHICH MAY ENHANCE THE
COVERAGE DURING THE AFTERNOON.
SCATTERED SHOWERS AND STORMS MAY LINGER THROUGH THE EVENING HOURS AS
THE COLD FRONT ENTERS THE EASTERN CAROLINAS. COOLING AT THE SURFACE
PLUS WARMING TEMPERATURES ALOFT SHOULD CAP OFF THE ATMOSPHERE TO
CONVECTION BY LATE EVENING WITH ONLY AN ISOLATED SHOWER OR TWO
POSSIBLE AFTER MIDNIGHT NEAR THE COAST. COMPARED TO MODEL SOLUTIONS
A FEW DAYS AGO THIS NOW LOOKS LIKE A CLEAN FRONTAL PASSAGE WITH
NORTHERLY SURFACE WINDS DEVELOPING OVERNIGHT ALL THE WAY DOWN TO THE
BEACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...COLD FRONT WILL WAVER NEAR THE CWA ON
FRIDAY BEFORE WEAKENING WELL SOUTH ON SATURDAY. THIS CREATES AN
UNSETTLED FRIDAY...BUT VERY NICE WEATHER FOR THE WEEKEND.
WEAK SHORTWAVE RIDGING OVERHEAD TO START THE PERIOD WILL INHIBIT
RAPID PROGRESSION OF A COLD FRONT WHICH WILL BE NEAR THE COAST
FRIDAY MORNING. WHILE MID-LEVEL RIDGING WILL WEAKEN THROUGH THE
DAY...THIS FLOW ALOFT WILL IMPEDE THE FRONT ENOUGH THAT IT WILL
REMAIN DRAPED IN THE VICINITY...SLOWING EVEN FURTHER AS IT
COMBINES WITH THE EXPECTED SEA BREEZE DURING THE AFTN. THIS HYBRID
FRONT/SEA BREEZE WILL SERVE AS A FOCUS FOR CONVECTION FRIDAY
AFTN/EVE...AND SREF PROBS RISE ABOVE 90% FOR 6-HR PRECIP TOTALS
ABOVE 0.01 INCHES ACROSS THE EASTERN THIRD OF THE CWA. WILL RAMP
POP UPWARDS TO HIGH- CHC FOR THE COASTAL COUNTIES AND A BIT INLAND
FROM THERE...BUT MAINTAIN JUST SCHC/VERY LOW CHC WELL INLAND WHERE
DRIER AIR WILL BE WORKING IN BEHIND THE FRONT. LATE FRIDAY AND
INTO FRIDAY NIGHT AS THE SEA BREEZE WEAKENS AND THE MID-LEVEL
RIDGE DISSIPATES...THE FRONT WILL MAKE ITS FINAL PUSH AND BE
ALIGNED NE TO SW BUT SOUTH OF THE CWA BY SATURDAY MORNING. THIS
WILL LEAVE COOLER AND MUCH DRIER AIR IN PLACE SATURDAY...WITH
PWATS FALLING TO AROUND 1.25 INCHES AT THE END OF THE PERIOD. WILL
MAINTAIN JUST A VERY SCHC FOR SHOWERS FAR SE ZONES...ESPECIALLY THE
FIRST HALF OF THE DAY...BUT OTRW EXPECT A DRY AND PLEASANT
SATURDAY.
TEMPS BOTH AFTNS WILL BE SIMILAR THANKS TO THE LACK OF COOL
ADVECTION ASSOCIATED WITH THE FRONT. HIGHS FRIDAY WILL RANGE FROM
AROUND 88 AT THE COAST TO 92 WELL INLAND...AND JUST A DEGREE OR SO
COOLER ON SATURDAY. LOWS BOTH NIGHTS WILL DROP TO NEAR SEASONABLE
LEVELS...A DEGREE OR TWO EITHER SIDE OF 70...ALTHOUGH SATURDAY NIGHT
WILL BE THE COOLER OF THE TWO.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 AM THURSDAY...ATYPICAL LATE AUGUST WEATHER TO START THE
PERIOD...BUT FOR THE BETTER...AS BRIGHT SUNSHINE WILL COMBINE WITH
LOW HUMIDITY TO MAKE SUNDAY A BEAUTIFUL DAY ACROSS THE AREA WITH
TEMPS NEAR SEASONABLE NORMS. BY MONDAY...RETURN FLOW WILL REDEVELOP
LOCALLY AS HIGH PRESSURE SPINS OFFSHORE AND A COLD FRONT APPROACHES
FROM THE WEST. MONDAY WILL LIKELY FEATURE ABOVE CLIMO TEMPS BUT WITH
INCREASING HUMIDITY AND AT LEAST ISOLATED CONVECTION POTENTIAL. FOR
THE LATTER HALF OF THE EXTENDED...THAT COLD FRONT IS BEING DRIVEN
SOUTHWARD BY SOME VORT ENERGY ROTATING AROUND THE SOUTHERN PERIPHERY
OF AN ANOMALOUSLY STRONG UPPER LOW OVER SE CANADA...WILL LIKELY
STALL ACROSS THE AREA. THIS WILL CREATE A PERIOD OF UNSETTLED
WEATHER FOR TUE/WED WITH TEMPS AROUND CLIMO LEVELS FOR HIGHS...BUT
POTENTIALLY VERY WARM OVERNIGHT LOWS DUE TO CLOUD COVER.
&&
.AVIATION /17Z THURSDAY THROUGH MONDAY/...
AS OF 18Z...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECT
THE REST OF TODAY AHEAD OF AN APPROACHING COLD FRONT POTENTIALLY
CREATING BRIEF PERIODS OF MVFR. OTHERWISE EXPECT VFR.
LATEST RADAR IMAGERY DEPICTS SHRA/TSRA ACTIVITY BEGINNING TO
INCREASE ACROSS THE AREA. THIS WILL CONTINUE THROUGH THIS AFTERNOON
AND INTO THE NIGHT HOURS AHEAD OF AN APPROACHING COLD FRONT. WEST-
SOUTHWEST WINDS WILL CONTINUE TO INCREASE OVER THE NEXT COUPLE OF
HOURS AS WELL...UP TO AROUND 12 KTS OR LESS. OVERNIGHT...ANY
LINGERING ACTIVITY WILL TAPER OFF AND WINDS WILL BECOME LIGHT OUT OF
THE WEST-NORTHWEST. LIGHT FOG IS POSSIBLE BEFORE DAYBREAK ON
FRIDAY...THUS HAVE INTRODUCED TEMPO GROUPS. FRIDAY MORNING...COLD
FRONT WILL BE PUSHING THROUGH THE AREA...WITH VFR BEHIND IT AND
LIGHT NORTHERLY WINDS THROUGH MIDDAY.
EXTENDED OUTLOOK...VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM THURSDAY...LATEST OBS SHOW LIGHT SOUTHWESTERLY WINDS
WITH SEAS IN THE 2 FT RANGE. FORECAST REMAINS IN GOOD SHAPE.
PREVIOUS DISCUSSION FOLLOWS:
A WEAK RIDGE OF HIGH PRESSURE EAST OF THE BAHAMAS WILL BREAK DOWN
TODAY AS A COLD FRONT APPROACHES FROM THE WEST. THIS FRONT IS
BEING DRIVEN EASTWARD BY LOW PRESSURE NEAR LAKE SUPERIOR. THE
FRONT SHOULD REACH THE BEACHES OF NORTH AND SOUTH CAROLINA AFTER
MIDNIGHT TONIGHT...PASSING WELL OFF THE COAST BEFORE DAYBREAK.
COMPARED TO MODEL SOLUTIONS JUST A COUPLE DAYS AGO THIS IS A MUCH
CLEANER AND MORE DRAMATIC FRONTAL PASSAGE...RATHER UNUSUAL FOR
MID-AUGUST.
SOUTHWEST WINDS AROUND 10 KNOTS TODAY WILL INCREASE TO 10-15 KT THIS
EVENING...BUT SHOULD VEER NORTHERLY AFTER MIDNIGHT AS THE FRONT
PUSHES THROUGH.
UNTIL THE FRONT ARRIVES...A WARM AND HUMID AIRMASS SHOULD GENERATE
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AT THE COAST.
STEERING WINDS ARE FROM THE WEST...MEANING THESE STORMS WILL GET
BLOWN OUT PAST THE BEACHES AND SHOULD AFFECT THE NEARSHORE WATERS.
REDUCED VISIBILITY IN HEAVY RAINFALL...GUSTY WINDS...AND FREQUENT
LIGHTNING ARE ALL EXPECTED THIS AFTERNOON WITH THESE STORMS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...COLD FRONT WILL BE NEAR THE COAST MUCH OF
FRIDAY AS IT WAVERS IN THE VICINITY THANKS TO MID-LEVEL RIDGING AND
WEAK STEERING FLOW. WITH THIS FRONT NEAR THE COASTAL WATERS ALL
DAY...WINDS WILL BE LIGHT BUT FEATURE A VARIETY OF DIRECTIONS...AND
THUS THE WAVE SPECTRUM WILL BE COMPRISED OF MANY WAVE GROUPS WITH
LOW AMPLITUDE...CREATING SEAS OF 1-2 FT. FRIDAY NIGHT THIS FRONT
WILL FINALLY GET A PUSH SOUTH AS HIGH PRESSURE EXPANDS FROM THE
NORTHEAST...AND THIS WILL CREATE NE WINDS AROUND 10 KTS ACROSS THE
WATERS...PERSISTING THROUGH SATURDAY. THIS MORE PRONOUNCED WIND
DIRECTION ALONG WITH HIGHER SPEEDS WILL DRIVE WAVE HEIGHTS SLIGHTLY
HIGHER...REACHING 1-3 FT FRIDAY NIGHT THROUGH SATURDAY NIGHT WITH A
NE WIND WAVE BECOMING PREDOMINANT.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...LIGHT NORTH WINDS SUNDAY WILL GRADUALLY VEER
TO THE SW BY MONDAY AS RETURN FLOW REDEVELOPS LOCALLY. SPEEDS SUNDAY
WILL BE LESS THAN 10 KTS...BUT MAY INCREASE TO 10-15 KTS DURING
MONDAY AS THE GRADIENT TIGHTENS AHEAD OF A COLD FRONT APPROACHING
FROM THE NW. SEAS WILL BE NEARLY ENTIRELY WIND-WAVE DRIVEN THIS
PERIOD...RISING FROM 1-2 FT SUNDAY TO 2-3 FT MONDAY...ALTHOUGH SOME
LONG PERIOD BACK-SWELL ASSOCIATED WITH A LOW PRESSURE NEAR BERMUDA
MAY BEGIN TO ENTER THE SPECTRUM VERY LATE IN THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...REK/TRA/CRM
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...SGL
MARINE...REK/TRA/JDW/CRM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1017 AM EDT THU AUG 20 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY ACROSS THE AREA TONIGHT INTO FRIDAY
CONTINUING A GOOD CHANCE FOR THUNDERSTORMS. SUNNY AND SEASONABLE
WEATHER IS EXPECTED 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.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM THURSDAY...12Z CHS SOUNDING SHOULD BE REPRESENTATIVE
OF THE AIRMASS TODAY. MODIFIED FOR HEATING...EXPECT LI TO -4C AND
MLCAPE TO 1400 J/KG. PRECIPITABLE WATER JUST OVER 2 INCHES WILL
COMBINE WITH DESTABILIZATION THIS AFTERNOON TO PRODUCE AN
ENVIRONMENT SUPPORTIVE OF CONVECTION WITH THE POTENTIAL FOR
LOCALLY HEAVY DOWNPOURS. EXTENSIVE MORNING CLOUD COVER WILL LIMIT
THE RATE OF DESTABILIZATION AND COULD RESULT IN LESS COVERAGE THAN
THE CURRENT FORECAST INDICATES. LATEST HRRR DOES HINT AT THIS
AS WELL. MAY TWEAK THE POPS A BIT AND KEEP THE ENTIRE CWA IN THE
40-50 PERCENT RANGE...BUT WILL ALSO HAVE TO WATCH A WEAKENING 500
MB SHORTWAVE MOVING ACROSS UPSTATE SC THIS MORNING WHICH MAY
ENHANCE THE COVERAGE DURING THE AFTERNOON.
SCATTERED SHOWERS AND STORMS MAY LINGER THROUGH THE EVENING HOURS AS
THE COLD FRONT ENTERS THE EASTERN CAROLINAS. COOLING AT THE SURFACE
PLUS WARMING TEMPERATURES ALOFT SHOULD CAP OFF THE ATMOSPHERE TO
CONVECTION BY LATE EVENING WITH ONLY AN ISOLATED SHOWER OR TWO
POSSIBLE AFTER MIDNIGHT NEAR THE COAST. COMPARED TO MODEL SOLUTIONS
A FEW DAYS AGO THIS NOW LOOKS LIKE A CLEAN FRONTAL PASSAGE WITH
NORTHERLY SURFACE WINDS DEVELOPING OVERNIGHT ALL THE WAY DOWN TO THE
BEACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...COLD FRONT WILL WAVER NEAR THE CWA ON
FRIDAY BEFORE WEAKENING WELL SOUTH ON SATURDAY. THIS CREATES AN
UNSETTLED FRIDAY...BUT VERY NICE WEATHER FOR THE WEEKEND.
WEAK SHORTWAVE RIDGING OVERHEAD TO START THE PERIOD WILL INHIBIT
RAPID PROGRESSION OF A COLD FRONT WHICH WILL BE NEAR THE COAST
FRIDAY MORNING. WHILE MID-LEVEL RIDGING WILL WEAKEN THROUGH THE
DAY...THIS FLOW ALOFT WILL IMPEDE THE FRONT ENOUGH THAT IT WILL
REMAIN DRAPED IN THE VICINITY...SLOWING EVEN FURTHER AS IT
COMBINES WITH THE EXPECTED SEA BREEZE DURING THE AFTN. THIS HYBRID
FRONT/SEA BREEZE WILL SERVE AS A FOCUS FOR CONVECTION FRIDAY
AFTN/EVE...AND SREF PROBS RISE ABOVE 90% FOR 6-HR PRECIP TOTALS
ABOVE 0.01 INCHES ACROSS THE EASTERN THIRD OF THE CWA. WILL RAMP
POP UPWARDS TO HIGH- CHC FOR THE COASTAL COUNTIES AND A BIT INLAND
FROM THERE...BUT MAINTAIN JUST SCHC/VERY LOW CHC WELL INLAND WHERE
DRIER AIR WILL BE WORKING IN BEHIND THE FRONT. LATE FRIDAY AND
INTO FRIDAY NIGHT AS THE SEA BREEZE WEAKENS AND THE MID-LEVEL
RIDGE DISSIPATES...THE FRONT WILL MAKE ITS FINAL PUSH AND BE
ALIGNED NE TO SW BUT SOUTH OF THE CWA BY SATURDAY MORNING. THIS
WILL LEAVE COOLER AND MUCH DRIER AIR IN PLACE SATURDAY...WITH
PWATS FALLING TO AROUND 1.25 INCHES AT THE END OF THE PERIOD. WILL
MAINTAIN JUST A VERY SCHC FOR SHOWERS FAR SE ZONES...ESPECIALLY THE
FIRST HALF OF THE DAY...BUT OTRW EXPECT A DRY AND PLEASANT
SATURDAY.
TEMPS BOTH AFTNS WILL BE SIMILAR THANKS TO THE LACK OF COOL
ADVECTION ASSOCIATED WITH THE FRONT. HIGHS FRIDAY WILL RANGE FROM
AROUND 88 AT THE COAST TO 92 WELL INLAND...AND JUST A DEGREE OR SO
COOLER ON SATURDAY. LOWS BOTH NIGHTS WILL DROP TO NEAR SEASONABLE
LEVELS...A DEGREE OR TWO EITHER SIDE OF 70...ALTHOUGH SATURDAY NIGHT
WILL BE THE COOLER OF THE TWO.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...ATYPICAL LATE AUGUST WEATHER TO START THE
PERIOD...BUT FOR THE BETTER...AS BRIGHT SUNSHINE WILL COMBINE WITH
LOW HUMIDITY TO MAKE SUNDAY A BEAUTIFUL DAY ACROSS THE AREA WITH
TEMPS NEAR SEASONABLE NORMS. BY MONDAY...RETURN FLOW WILL REDEVELOP
LOCALLY AS HIGH PRESSURE SPINS OFFSHORE AND A COLD FRONT APPROACHES
FROM THE WEST. MONDAY WILL LIKELY FEATURE ABOVE CLIMO TEMPS BUT WITH
INCREASING HUMIDITY AND AT LEAST ISOLATED CONVECTION POTENTIAL. FOR
THE LATTER HALF OF THE EXTENDED...THAT COLD FRONT IS BEING DRIVEN
SOUTHWARD BY SOME VORT ENERGY ROTATING AROUND THE SOUTHERN PERIPHERY
OF AN ANOMALOUSLY STRONG UPPER LOW OVER SE CANADA...WILL LIKELY
STALL ACROSS THE AREA. THIS WILL CREATE A PERIOD OF UNSETTLED
WEATHER FOR TUE/WED WITH TEMPS AROUND CLIMO LEVELS FOR HIGHS...BUT
POTENTIALLY VERY WARM OVERNIGHT LOWS DUE TO CLOUD COVER.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...PATCHY AREAS OF MVFR THIS MORNING DUE TO FOG...WITH
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED
TODAY AND THIS EVENING AHEAD OF AN APPROACHING COLD FRONT.
LATEST RADAR IMAGERY REMAINS FAIRLY QUIET THIS MORNING WITH ISOLATED
PATCHES OF -DZ IN SOME LOCATIONS. OBSERVATIONS REPORT PATCHY AREAS
OF FOG WHICH ARE CREATING MVFR. EXPECT THESE CONDITIONS TO IMPROVE
OVER THE NEXT HOUR OR TWO. WILL SEE INCREASING SOUTH-SOUTHWEST WINDS
THROUGH THE MORNING HOURS...REACHING TO AOB 12 KTS BY THIS
AFTERNOON. ISOLATED TO SCATTERED SHRA/TSRA EXPECTED THROUGHOUT THE
DAY INTO THE EVENING HOURS AHEAD OF AN APPROACHING COLD
FRONT...INITIALIZING AT THE COAST LATE MORNING AND MOVING INLAND.
OVERNIGHT...ANY LINGERING ACTIVITY WILL TAPER OFF AND WINDS WILL
BECOME LIGHT AS THE COLD FRONT MOVES INTO THE FORECAST AREA.
LIGHT FOG IS POSSIBLE BEFORE DAYBREAK ON FRIDAY.
EXTENDED OUTLOOK...VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH THE WEEKEND.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM THURSDAY...A WEAK RIDGE OF HIGH PRESSURE EAST OF
THE BAHAMAS WILL BREAK DOWN TODAY AS A COLD FRONT APPROACHES FROM
THE WEST. THIS FRONT IS BEING DRIVEN EASTWARD BY LOW PRESSURE NEAR
LAKE SUPERIOR. THE FRONT SHOULD REACH THE BEACHES OF NORTH AND
SOUTH CAROLINA AFTER MIDNIGHT TONIGHT...PASSING WELL OFF THE COAST
BEFORE DAYBREAK. COMPARED TO MODEL SOLUTIONS JUST A COUPLE DAYS
AGO THIS IS A MUCH CLEANER AND MORE DRAMATIC FRONTAL
PASSAGE...RATHER UNUSUAL FOR MID-AUGUST.
SOUTHWEST WINDS AROUND 10 KNOTS TODAY WILL INCREASE TO 10-15 KT THIS
EVENING...BUT SHOULD VEER NORTHERLY AFTER MIDNIGHT AS THE FRONT
PUSHES THROUGH.
UNTIL THE FRONT ARRIVES...A WARM AND HUMID AIRMASS SHOULD GENERATE
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AT THE COAST.
STEERING WINDS ARE FROM THE WEST...MEANING THESE STORMS WILL GET
BLOWN OUT PAST THE BEACHES AND SHOULD AFFECT THE NEARSHORE WATERS.
REDUCED VISIBILITY IN HEAVY RAINFALL...GUSTY WINDS...AND FREQUENT
LIGHTNING ARE ALL EXPECTED THIS AFTERNOON WITH THESE STORMS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...COLD FRONT WILL BE NEAR THE COAST MUCH OF
FRIDAY AS IT WAVERS IN THE VICINITY THANKS TO MID-LEVEL RIDGING AND
WEAK STEERING FLOW. WITH THIS FRONT NEAR THE COASTAL WATERS ALL
DAY...WINDS WILL BE LIGHT BUT FEATURE A VARIETY OF DIRECTIONS...AND
THUS THE WAVE SPECTRUM WILL BE COMPRISED OF MANY WAVE GROUPS WITH
LOW AMPLITUDE...CREATING SEAS OF 1-2 FT. FRIDAY NIGHT THIS FRONT
WILL FINALLY GET A PUSH SOUTH AS HIGH PRESSURE EXPANDS FROM THE
NORTHEAST...AND THIS WILL CREATE NE WINDS AROUND 10 KTS ACROSS THE
WATERS...PERSISTING THROUGH SATURDAY. THIS MORE PRONOUNCED WIND
DIRECTION ALONG WITH HIGHER SPEEDS WILL DRIVE WAVE HEIGHTS SLIGHTLY
HIGHER...REACHING 1-3 FT FRIDAY NIGHT THROUGH SATURDAY NIGHT WITH A
NE WIND WAVE BECOMING PREDOMINANT.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...LIGHT NORTH WINDS SUNDAY WILL GRADUALLY VEER
TO THE SW BY MONDAY AS RETURN FLOW REDEVELOPS LOCALLY. SPEEDS SUNDAY
WILL BE LESS THAN 10 KTS...BUT MAY INCREASE TO 10-15 KTS DURING
MONDAY AS THE GRADIENT TIGHTENS AHEAD OF A COLD FRONT APPROACHING
FROM THE NW. SEAS WILL BE NEARLY ENTIRELY WIND-WAVE DRIVEN THIS
PERIOD...RISING FROM 1-2 FT SUNDAY TO 2-3 FT MONDAY...ALTHOUGH SOME
LONG PERIOD BACK-SWELL ASSOCIATED WITH A LOW PRESSURE NEAR BERMUDA
MAY BEGIN TO ENTER THE SPECTRUM VERY LATE IN THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...CRM/TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...SGL
MARINE...TRA/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1252 AM EDT THU AUG 20 2015
.SYNOPSIS...
UNSETTLED WEATHER WILL CONTINUE THROUGH THURSDAY. A WEAK COLD
FRONT WILL MOVE ACROSS THE AREA FRIDAY. LESS COVERAGE OF SHOWERS
AND THUNDERSTORMS CAN BE EXPECTED FRIDAY THROUGH EARLY NEXT WEEK
WITH TYPICAL LATE SUMMERTIME TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 1000 PM THURSDAY...THE LARGE INLAND CONVECTIVE BLOBS CONTINUE
TO DECAY EARLY THIS MORNING...WHILE A VERY FEW SHOWERS HAVE RECENTLY
DEVELOPED ACROSS COASTAL NORTH CAROLINA. THIS IS ALL WELL-HANDLED IN
THE EVENING SHIFT`S FORECAST AND NO SIGNIFICANT CHANGES ARE NEEDED
WITH THIS EARLY-MORNING NEAR-TERM UPDATE. FORECAST LOWS WERE BUMPED
UP A DEGREE OR TWO BASED ON LATEST TEMPERATURES. DISCUSSION FROM
1000 PM FOLLOWS...
THE BRUNT OF A LARGE CONVECTIVE COMPLEX WAS PASSING BY TO OUR N WITH
THE SOUTHERN PORTION OF THIS AREA OF THUNDERSTORMS MOVING ACROSS A
PORTION OF THE FORECAST AREA... BASICALLY N OF A FLO TO CPC TO
BURGAW LINE. THE OVERALL INTENSITY OF RAINFALL CONTINUES TO DIMINISH
AND ALTHOUGH A BRIEF HEAVY DOWNPOUR IS POSSIBLE...OVERALL RAINFALL
RATES GOING FORWARD WILL NOT BE SIGNIFICANT HERE FOR THE REMAINDER
OF THE NIGHT.
ANOTHER MUCH SMALLER BATCH OF THUNDERSTORMS WAS ONGOING TO OUR SW
ACROSS SOUTHERN SOUTH CAROLINA. THE NORTHERN PERIPHERY OF THIS
AREA OF STORMS MAY SKIRT PORTIONS OF WILLIAMSBURG AND GEORGETOWN
COUNTIES...12-2 AM. A HEAVY DOWNPOUR IS POSSIBLE...BUT SEVERE
WEATHER IS NOT EXPECTED.
I AM INCLINED TO THINK THAT WE WILL GET SOME REDEVELOPMENT OF
CONVECTION OVER THE WARM OCEAN WATERS LATE TONIGHT AND EARLY THU
MORNING AS HAS BEEN THE CASE FOR THE LAST FEW NIGHTS. THE HIGH
RESOLUTION HRRR MODEL IS FINALLY BEGINNING TO SETTLE ON SUCH A
SOLUTION. IF THIS CONVECTION DOES INDEED MATERIALIZE...IT MAY
SKIRT PORTIONS OF THE COAST...MAINLY FROM THE GRAND STRAND THROUGH
CAPE FEAR EARLY IN THE MORNING.
GIVEN THE EXTENT AND MAGNITUDE OF THE RAINFALL TODAY AND TONIGHT...
WILL CONTINUE TO INCLUDE PATCHY LATE NIGHT FOG ACROSS PORTIONS OF
THE AREA.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...A MID LEVEL CYCLONE WILL MOVE ACROSS THE
GREAT LAKES WITH A BROAD ZONAL FLOW PUSHING A COLD FRONT ACROSS
THE AREA EARLY FRIDAY. BY THE END OF THE PERIOD MID LEVEL HIGH
PRESSURE BUILDS BACK IN FROM THE SOUTH WITH ANY APPRECIABLE
AFFECTS FROM THE FRONT BASICALLY GONE. FOR THURSDAY...WEAK SURFACE
TROUGHING WILL STILL RESIDE ACROSS THE AREA AND GOOD CHANCE POPS
REMAIN IN THE FORECAST. POPS DECREASE SOMEWHAT FOR FRIDAY AS THE
WEAK FRONT HAS A SIGNIFICANT SUBSIDENCE INVERSION IN THE 700-850MB
LAYER WHICH WILL MAKE CONVECTIVE DEVELOPMENT MORE CHALLENGING THAN
PREVIOUS DAYS. THERE REMAINS A VERY MOIST PROFILE HOWEVER AND
LOWER CHANCE POPS SHOULD BE A GOOD COMPROMISE. TEMPERATURES CHANGE
LITTLE THROUGH THE PERIOD WITH HIGHS IN THE 90S AND LOWS IN THE
70S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...COLD FRONT AND ITS ASSOCIATED MOISTURE
BOTH MOVING OFF THE COAST EARLY SATURDAY FOR A RAIN FREE WEEKEND
DESPITE SOME LAGGING UPPER LEVEL ENERGY PASSING THROUGH SUNDAY AND
SUNDAY NIGHT. MOISTURE RETURN WILL BEGIN GRADUALLY ON MONDAY AS A
PIEDMONT TROUGH DEVELOPS AND A MID LEVEL SHEAR LINE REMAINS ABOVE
THE AREA. COLD FRONT AND HEALTHY UPPER TROUGH DROP INTO THE AREA
TUESDAY AND WEDNESDAY AND LIKELY BRINGING SOME PRETTY UNSETTLED
WEATHER. OUR BEACHES MAY EVEN BEGIN SEEING SOME DANNY SWELLS EARLY
NEXT WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...SHOWERS CONTINUE EARLY THIS MORNING. HI RESOLUTION
MODELS SUGGEST RAIN DYING OFF AND ENDING SHORTLY...PERHAPS SHIFTING
OFFSHORE BY DAYBREAK. EXPECT BROKEN CLOUD COVER AT KFLO/KLBT TO
TEMPER ANY POTENTIAL FOG ...ALTHOUGH CANT TOTALLY RULE OUT BRIEF
MVFR VSBYS. SOME MID LEVEL LIFT SUGGESTS POTENTIAL ISOLATED SHOWERS
COULD CONTINUE. AT THE COASTAL TERMINALS DO NOT EXPECT ANY FOG
ISSUES THIS MORNING. SOME LIFT IN THE PRE-DAWN HOURS SUGGEST SHOWER
ACTIVITY AT KILM BECOMING MORE WIDESPREAD IN THE MID MORNING HOURS
ALL COASTAL TERMINALS WITH VCTS LIKELY. CONVECTION WORKS INLAND BY
AFTERNOON. WINDS WILL BE SW-W EARLY BECOMING SW BY MID-LATE MORNING.
EXTENDED OUTLOOK...VFR...WITH SCATTERED SHOWERS AND THUNDERSTORMS
THROUGH FRIDAY.
&&
.MARINE... NEAR TERM /THROUGH TONIGHT/...
AS OF 1245 AM THURSDAY...VIRTUALLY NO CHANGES WERE NEEDED TO THE
FORECAST WITH THIS EARLY-MORNING NEAR-TERM UPDATE. DISCUSSION FROM
1000 PM WEDNESDAY FOLLOWS...
SOUTHWEST WINDS WILL REMAIN ACROSS THE WATERS THROUGH THE NIGHT.
WIND SPEEDS WILL BE UP TO 15 KT. SEAS 2 TO 3 FT. A 8 TO 9 SECOND ESE
SWELL WILL REMAIN AND IN THE COMING DAYS THIS SWELL WILL ONLY
INCREASE IN STRENGTH. WE SHOULD AGAIN SEE CONVECTION DEVELOPING
ACROSS THE WATERS WITH THE APPROACH OF DAYBREAK THU.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...THE PIEDMONT TROUGH WILL BECOME MORE A
LITTLE BETTER DEFINED THURSDAY AND WIND FIELDS WILL SHOULD RESPOND
WITH A SOUTHWEST FLOW OF 10-15 KNOTS...MOSTLY IN THE LOWER END OF
THE RANGE. A WEAK FRONT WILL PUSH ACROSS THE WATERS EARLY FRIDAY
WITH THE FRONT AND THE LAND BREEZE PROVIDING A BRIEF OFFSHORE
FLOW. BY LATER IN THE DAY LIGHT AND VARIABLE WINDS DEVELOP UNDER A
WEAK PRESSURE PATTERN. AS FOR SEAS...GENERALLY 2-3 FEET THROUGH
THE PERIOD.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...NORTHEAST WINDS ON SATURDAY AS COLD FRONT
SLOWLY MOVES OFF TO OUR SOUTH. WITH NO BIG PUSH OF HIGH PRESSURE
BEHIND THIS BOUNDARY WIND SPEEDS WILL REMAIN VERY LIGHT. NORTHEAST
OR EAST WINDS ON SUNDAY AS THE BOUNDARY DISSIPATES SOUTH OF THE
AREA. A MORE TYPICAL SOUTHWESTERLY WIND SHOULD RETURN ON MONDAY AS A
PIEDMONT TROUGH BEGINS TO DEVELOP.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RJD/TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
951 PM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 947 PM CDT FRI AUG 21 2015
MINOR CHANGES WERE DONE TO THE GRIDS TO INCREASE WINDS A BIT IN SE
ND AS LOW LEVEL JET GOING GOING AND TO INCREASE DEW PTS AS THEY
ARE CLIMBING A BIT HIGHER IN SOME AREAS THAN FCST. OVERALL THOUGH
MONITORING HRRR AND OTHER VERY SHORT RANGE COVECTIVE MODELS STILL
INDICATES ABOUT A 40 KT LOW LEVEL JET INTO ERN ND OVERNIGHT...AND
RAP MODEL ESPECIALLY HAS ONE AREA OF ENHANCED INSTABILITY MOVING
INTO SE ND TO THE CENTRAL RRV 09Z-10Z PERIOD. BUT BEST MOISTURE
SATURATION IS MORE NORTH OF THE WARM FRONT WHICH IS LOCATED NR THE
INTL BORDER. THUS HRRR HAS BEST COVERAGE OF ANY STORMS MORE TOWARD
WINNIPEG. ANOTHER PIECE OF A STRONGER LOW LEVEL JET OVER NEBRASKA
AND SOME MODELS BREAK OUT TSTMS IN SCNTRL SD WITH THIS. SO OVERALL
NOT SEEING CLEAR CUT SIGNS OF LATE NIGHT CONVECTION IN ERN ND/RRV
BUT STILL WAY TO MANY VARIABLES TO REMOVE. THUS CONTINUING WITH
LOW POPS.
UPDATE ISSUED AT 638 PM CDT FRI AUG 21 2015
THICKER HIGH CLOUDS REMAIN OVER THE NRN RRV INTO NW MN WITH CLEAR
SKIES DVL-FARGO SOUTHWARD...THOUGH SOME HIGH LEVEL SMOKE. BETTER
MID-HIGH LEVEL MOISTURE IN A BAND FROM CNTRL MONTANA ACROSS NW ND
INTO MANITOBA. IN THIS AREA IS WHERE THE THREAT FOR A FEW SHOWERS
WILL BE THIS EVENING...WHICH IS WEST AND NORTH OF OUR AREA. MAIN
THREAT WILL BE LATER TONIGHT TO SEE IF INCREASING 850 MB JET
COMBINED WITH 850 MOISTURE AND INSTABILITY INCREASE CAN BE ENOUGH
TO GENERATE SOME STORMS IN CNTRL ND OR INTO THE DVL REGION. HRRR
MODEL STILL SHOWING THAT POTENTIAL. SO FAR FCST OK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 25
THE MAIN CHALLENGE WILL BE SEVERE POTENTIAL ON SATURDAY...RAIN
THEN WIND. MODELS HAVE COME INTO PRETTY GOOD AGREEMENT WITH THIS
SYSTEM...WITH THE GFS/ECMWF VERY SIMILAR WITH ALL FIELDS.
FOR TONIGHT...A LLJ WILL INCREASE TO ABOUT 30-40KT INTO NE SD
AROUND 6-9Z. THERE WILL ALSO BE A FAIRLY RAPID INCREASE TO MID
LEVEL MOISTURE AND INSTABILITY...WITH SHOWALTERS FALLING INTO THE
-6 TO -8C RANGE ALONG WITH 850MB CAPE OF AROUND 2000 J/KG.
THEREFORE...WILL MENTION LOW POPS IN THE SOUTH AND LOW CHANCE POPS
IN THE NW FOR ELEVATED SHOWERS AND STORMS LATE TONIGHT.
ON SATURDAY...A STRONG COLD FRONT AND SFC LOW WILL MOVE TO NEAR
THE RED RIVER VALLEY IN THE 18-21Z TIMEFRAME...THEN RACE INTO THE
EASTERN ZONES AROUND 00-03Z. THERE WILL BE STRONG INSTABILITY
PARAMETERS WITH MLCAPE OF NEAR 3000 J/KG IF WE CAN GET SFC
DEWPOINTS INTO THE MID/UPPER 60S. THE STRONGER DEEP LAYERED SHEAR
DOES LAG THE WARM SECTOR SOME...BUT GIVEN STRONG WAVE/FORCING AND
SFC CONVERGENCE NEAR THE FRONT...EXPECT SOME SEVERE STORMS. THE
BEST COVERAGE FOR SEVERE STORMS SHOULD OCCUR EAST OF THE VALLEY.
IT IS INTERESTING TO NOTE THAT THE NAM HAS MORE OF A CLOSED SFC
LOW NEAR KGFK AROUND 21Z...MOVING INTO NW MN THEREAFTER. SHOULD
THIS OCCUR...THEN THE TORNADO THREAT WOULD INCREASE NEAR AND NORTH
OF THIS LOW...SO SOMETHING TO WATCH. TEMPS WILL LIKELY REMAIN IN
THE 70S FOR THE MOST PART GIVEN CLOUDS AND THE COLD FRONT.
ON SAT NIGHT...WINDS WILL INCREASE AND EXPECT A DEFORMATION
SHOWER/RAIN BAND TO DEVELOP IN THE NORTH OVERNIGHT. SOME AREAS
COULD GET AN INCH OR MORE OF RAIN NEAR HEAVIER PERSISTENT SHOWERS
IN THE NORTH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 250 PM CDT FRI AUG 21 2015
ON SUNDAY...IT WILL BE COOL...WINDY WITH MAINLY MORNING SHOWERS
IN THE NORTH AND EAST. TEMPS WILL BE WELL BELOW NORMAL ALONG WITH
STRONG WINDS. THERE WILL BE ABOUT 45-50KT TO MIX FROM THE NW...SO
WE MAY NEED A WINDY ADVISORY HEADLINE FOR THE VALLEY AND POINTS
WEST...BUT STILL TIME TO IRON OUT THESE DETAILS OUT.
FOR MONDAY...IT WILL BE DRY AND COOL WITH TEMPS BELOW NORMAL.
FOR MONDAY NIGHT THROUGH THURSDAY...MODELS WERE IN GOOD
AGREEMENT ON POSITIONING OF UPPER AIR AND SFC FEATURES THIS RUN.
SFC HIGH PRESSURE IS FORECAST TO BE OVER THE AREA WITH THE AXIS
CENTERED OVER THE RED RIVER VALLEY...AND SLOWLY DRIFT SE THRU THE
PERIOD. OTHERWISE...THE UPPER RIDGE OVER THE INTERMOUNTAIN WEST
CONTINUES TO BUILD AND SHIFT E THRU THE PERIOD. THIS IS EXPECTED
TO BRING A RETURN TO WARMER TEMPERATURES...WITH MAINLY 80S WEST
AND UPPER 70S EAST. A FEW SHORT WAVES WILL PROPAGATE THRU THE
FLOW...BRINGING A FEW CHANCES FOR PCPN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 638 PM CDT FRI AUG 21 2015
CHANGEABLE PERIOD COMING UP...WITH MAIN QUESTION BEING TIMING OF
ANY SHOWERS AND STORMS LATE TONIGHT INTO SATURDAY. HARD TO TIME
THINGS THAT FAR OUT SO BUT IN TEMPO GROUPS WHEN THINKING IS BEST
CHANCE FOR ANY SHOWERS/STORMS. WILL NEED TO WATCH FOR A GUSTY
SOUTH-SOUTHEAST WIND OVERNIGHT INTO FARGO AND A GUSTY SOUTH-
SOUTHEAST WIND OVER THE RRV INTO NW MN SATURDAY DAYTIME AHD OF
COLD FRONT. WINDY WEST-NORTHWEST WINDS BEHIND COLD FRONT ENTERING
DVL REGION SAT AFTN AND RRV LATE AFTN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...HOPKINS/DK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
702 PM EDT THU AUG 20 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 FRIDAY 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 /FRIDAY 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 /18Z THURSDAY THROUGH TUESDAY/...
COOL AIR ALOFT WILL SUPPORT LAKE EFFECT CLOUDS TONIGHT AND FRI
MORNING OVER LAKE ERIE. A TROUGH MOVING EAST ACROSS LAKE ERIE WILL
CAUSE THE MEAN LOW LEVEL WINDS TO VEER TO WNW WHICH WILL PROBABLY
PRODUCE SCT TO BKN CONDITIONS AT ERI LATE TONIGHT AND FRI MORNING.
HIGH PRESSURE PUSHES NE OVER OH FOR FRI AFTERNOON WHICH SHOULD
LEAD TO SLOW DISSIPATION OF THE LAKE EFFECT CLOUDS FRI AFTERNOON.
DAYTIME HEATING MAY PRODUCE SCT CU IN OTHER PARTS OF THE EAST BY
MIDDAY FRI BUT THIS CU WILL DISSIPATE BY EARLY EVENING.
WINDS WILL CONTINUE TO DIMINISH NEXT FEW HOURS AS TEMPS COOL AND
AIRMASS STABILIZES EXCEPT WINDS MAY CONTINUE TO RUN 8 TO 10 KNOTS AT
ERI FOR MUCH OF THE NIGHT.
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. 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 FRIDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...JAMISON
NEAR TERM...JAMISON/MULLEN
SHORT TERM...JAMISON
LONG TERM...LAPLANTE
AVIATION...ADAMS
MARINE...LAPLANTE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
334 PM EDT THU AUG 20 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 /THROUGH TONIGHT/...
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 /FRIDAY 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 /18Z THURSDAY THROUGH TUESDAY/...
A COLD FRONT HAS MOVED EAST OF THE TAF SITES AND IS NOW IN
WESTERN NY AND PA. SCATTERED TO BROKEN CUMULUS DECK NEAR
3000-4000FT HAS DEVELOPED IN THE WAKE OF THE FRONT WITH SOMEWHAT
THICKER CLOUDS IN THE LEE OF LAKE MICHIGAN WHICH WILL SPREAD TO
NEAR TOL THIS AFTERNOON. SOUTHWEST WINDS OF 15-25 KNOTS WILL
DIMINISH TOWARD SUNSET AS DRIER AIR CONTINUES TO OVERSPREAD THE
REGION. DO NOT EXPECT FOG OVERNIGHT EXCEPT AT KYNG WHERE MORE
RAIN FELL AND THAT REGION IS MORE PRONE TO GET EARLY MORNING FOG
IN THE LATE SUMMER/EARLY AUTUMN MORNINGS. EXPECT VFR CONDITIONS
FRIDAY AND THROUGH THE WEEKEND.
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. 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 FRIDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...JAMISON
NEAR TERM...JAMISON
SHORT TERM...JAMISON
LONG TERM...LAPLANTE
AVIATION...LAPLANTE
MARINE...LAPLANTE
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
913 PM CDT FRI AUG 21 2015
.UPDATE...
AREA OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO MOVE ACROSS
PARTS OF NORTHERN OK. ADDITIONAL SHOWERS/STORMS MAY BE POSSIBLE
OVERNIGHT AS A DISTURBANCE MOVES ACROSS THE REGION. HOWEVER...
CHANCES OF ADDITIONAL ACTIVITY SEEM LOWER SO HAVE LOWERED POPS IN
SOME AREAS FOR THIS EVENING AND OVERNIGHT. UPDATES OUT SOON.
&&
.PREV DISCUSSION... /ISSUED 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 / 30 10 60 30
HOBART OK 71 96 72 85 / 20 10 40 30
WICHITA FALLS TX 74 97 75 93 / 30 10 20 40
GAGE OK 68 94 65 80 / 20 0 60 20
PONCA CITY OK 70 91 67 82 / 50 20 70 10
DURANT OK 73 94 75 93 / 30 10 10 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
25/30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
230 AM EDT THU AUG 20 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION THURSDAY INTO
THURSDAY NIGHT. LOWER HUMIDITY AND MAINLY DRY WEATHER WILL RETURN
TO MOST OF CENTRAL PA FRIDAY THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWER ACTIVITY IS FADING WITH THE LOSS OF HEATING AND INCREASED
STABILITY. THE HRRR CONTINUES WITH THE IDEA OF SCATTERED
ACTIVITY MEANDERING ABOUT FOR THE OVERNIGHT SO WHILE I LOWERED
POPS...I DID NOT ELIMINATE THE MENTION OF RAIN ALTOGETHER. IT DOES
LOOK LIKE MOST AREAS WILL REMAIN RAIN FREE FOR THE REST OF THE
NIGHT HOWEVER.
THE OVERNIGHT PERIOD WILL REMAIN WARM AND MUGGY WITH LOWS IN THE
UPPER 60S TO LOW 70S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
AN INCREASE IN CYCLONIC FLOW ALOFT AHEAD OF IMPRESSIVE MID LEVEL
CYCLONE FOR THIS TIME OF YEAR OVER THE UPPER GREAT LAKES REGION...
AND STRENGTHENING OF THE S-SE LLJ SHOULD RESULT IN AN INCREASE IN
SHOWER ACTIVITY ONCE AGAIN AFTER 12Z. A BLEND OF NEAR AND SHORT
TERM MODEL QPF TARGETS AN AXIS OF PCPN FROM THE SRN DELMARVA INTO
ERN PA WHICH MAY BE ENHANCED BY SSERLY FEED OF ATLANTIC
MOISTURE.
THE SFC COLD FRONT IS FORECASTED TO MOVE THROUGH THE CENTRAL
MOUNTAINS BY LATE AFTERNOON AND THE SUSQUEHANNA VALLEY THURSDAY
EVENING.
THE BEST SHEAR VALUES LOOK TO BE NORTH AND WEST OF THE SPINE OF
THE APPALACHIANS WITH THE SREF INDICATING A 70% PROBABILITY OF
SHEAR GREATER THAN 30 KTS IN THE NORTHWEST MOUNTAINS AND WESTERN
LAURELS LATE TOMORROW AFTERNOON. SURFACE CAPE VALUES WILL RANGE
FROM 1000 TO 2000 J/KG IN THE AFTERNOON.
THE BIGGEST CONCERN FOR THURSDAY IS THE THREAT FOR FLASH FLOODING
AS WE HAVE ANOMALOUSLY HIGH PWATS BETWEEN TWO AND THREE STANDARD
DEVIATIONS ABOVE NORMAL. RFC FFG MOSAIC INDICATES THAT AMTS ARE
HIGHEST /2 TO 4 INCHES OVER A 6-HOUR PERIOD/ WHERE WE EXPECT THE
HEAVIEST RAIN TO FALL - ACROSS THE ERN HALF OF THE CWA THURSDAY
AFTERNOON AND NIGHT.
MODEL/ENSEMBLE CONSENSUS QPF STILL POINTS TWD JUST UNDER ONE INCH
ACROSS THE WESTERN PART OF THE CWA...AND 1-1.5 INCHES ACROSS THE
EAST...WITH OBVIOUSLY SOME HIGHER NARROW-BANDED 2+ INCH TOTALS.
HIGH TEMPERATURES ON THURSDAY WILL REMAIN MILD RANGING FORM THE
MID 70S IN THE NORTHWEST MOUNTAINS TO THE LOW 80S ACROSS THE LOWER
SUSQUEHANNA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE WILL BE IN CONTROL ACROSS MOST OF THE AREA THIS
WEEKEND...AND PROVIDE GENERALLY FAIR WEATHER WITH SLIGHTLY BELOW
TO NEAR-AVERAGE TEMPS. THE NEXT COLD FRONT IS FCST TO ARRIVE ON
MONDAY BEFORE ANOTHER PUSH OF COOLER AND DRIER AIR FOR TUESDAY.
THE DAY2-3 FRONTAL BOUNDARY WILL LINGER OFF THE NORTHEAST/MID-
ATLC COAST THIS WEEKEND AND MAY TRY TO DRIFT WWD WITH TIME. MODEL
CONSENSUS HAS PUSHED N-S PCPN AXIS FARTHER OFF THE COAST AND
THEREFORE WILL ONLY KEEP SCHC POPS ACROSS THE FAR ERN ZONES ON
SUNDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
MOIST SERLY FLOW COMBINING WITH COOLING OF BLYR TO PRODUCE
EXPANDING STRATUS ACROSS CENTRAL PA EARLY THIS AM. CLIMATOLOGY IN
THIS SCENARIO...AS WELL AS SREF OUTPUT...INDICATE LIKELY IFR CIGS
EARLY THIS MORNING AT THE HIGH TERRAIN AIRFIELDS OF KBFD AND KJST
AND PRIMARILY MVFR ELSEWHERE. HOWEVER...CAN/T RULE OUT A PERIOD OF
IFR CIGS AT KAOO/KUNV ARND 08Z-12Z.
PERSISTENT SERLY FLOW SHOULD KEEP THE STRATUS IN PLACE ACROSS
CENTRAL PA TODAY. HOWEVER...MDL SOUNDINGS SUPPORT SOME MODEST
IMPROVEMENT BY LATE AM TODAY...WITH MANY LOCATIONS REMAINING IN
THE MVFR CATEGORY AND KMDT/KLNS POSSIBLY BECOMING VFR. FOCUS FOR
THIS AFTN/EVENING WILL SHIFT TOWARD APPROACHING COLD FRONT...WHICH
WILL PRODUCE LOCALLY HEAVY SHRA/TSRA AS IT PUSHES EAST ACROSS THE
REGION. MOST LOCATIONS WILL LIKELY EXPERIENCE BRIEF IFR REDUCTIONS
AS THESE SHRA/TSRA PASS THRU...DESPITE MORE FAVORABLE PREDOMINANT
CONDS.
A RETURN TO VFR CONDS APPEARS LIKELY ACROSS THE WESTERN HALF OF PA
BY 00Z FRIDAY...AS A DRIER WEST FLOW ARRIVES IN WAKE OF FRONT.
HOWEVER...THE SLOW MOVING FRONT COULD CREATE LINGERING SHRA AND
POSSIBLE REDUCTIONS INTO THE EVENING OVER THE EASTERN HALF OF THE
STATE.
OUTLOOK...
FRI...AM FOG POSS KBFD.
SAT-MON...NO SIG WX EXPECTED.
&&
.HYDROLOGY...
AN ELEVATED RISK OF VERY LOCALIZED FLASH FLOODING WILL EXIST THURSDAY
INTO THURSDAY NIGHT...MAINLY ACROSS THE EASTERN HALF OF PENN.
NARROW...NORTH-SOUTH BANDS OF HEAVY TO LOCALLY EXCESSIVE RAINFALL
ARE POSSIBLE WHICH MAY RESULT IN SOME FLASH FLOODING AND SHARP
RISES ON SMALL STREAMS/CREEKS. AT THIS TIME CONFIDENCE IS LOW IN
DETERMINING THE EXACT LOCATION OF THE HEAVIEST RAIN BUT THE LARGE
SCALE PATTERN AND ATMOS MOISTURE IS SUPPORTIVE OF 2+ INCH AMOUNTS
IN A SHORT DURATION.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...GARTNER/STEINBUGL
AVIATION...FITZGERALD
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1033 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 10:25 PM FRIDAY...A FEW LIGHT SHOWERS HAVE DEVELOPED OVER
WESTERN NORTH CAROLINA WHICH MAY REFLECT SOME WEAK FORCING IN
ADVANCE OF A WEAK VORTICITY MAX THAT IS MOVING TOWARDS THE AREA.
SOME WIDELY SCATTERED RAIN SHOWERS WILL REMAIN POSSIBLE THROUGH THE
NIGHT AND INTO THE MORNING HOURS.
AS OF 745 PM FRIDAY...AREA IS ENTIRELY CLEAR OF ANY RADAR ECHOES AT
THE MOMENT WITH LIGHT AND VARIABLE WINDS AND PARTLY CLOUD SKIES.
CONVECTIVE ACTIVITY INDICATED BY CAMS WAS OVERDONE BY THE MODELS.
CURRENT EXPECTATIONS ARE FOR NO PRECIP THROUGH 5Z AT LEAST. AFTER
5Z...A WEAK SHORTWAVE EMBEDDED IN THE SOUTHWESTERLY FLOW ALOFT MAY
KICK-OFF A FEW WIDELY SCATTERED AND WEAK SHOWERS...ESPECIALLY IN
EASTERN PARTS OF THE CWA WHICH HAS SLIGHTLY BETTER MOISTURE. A
BETTER CHANCE FOR PRECIPITATION WILL BE SATURDAY AFTERNOON AS THE
MAIN SHORTWAVE APPROACHES FROM THE WEST.
AS OF 510 PM 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 /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...GOOD VFR CONDITIONS THIS EVENING AS CONVECTIVE ACTIVITY
FORECAST BY HIGH-RES MODELS WAS OVERDONE. A WEAK SHORTWAVE EMBEDDED
IN SOUTHWESTERLY FLOW COULD LEAD TO SOME SHOWER ACTIVITY LATER
TONIGHT...BUT COVERAGE WOULD BE WIDELY SCATTERED. SOME RH INCREASE
AROUND THE 5000 FT LEVEL WITH BKN SKIES DUE TO THE PASSING SHORT
WAVE TOMORROW MORNING...THIS IS FOLLOWED BY AN IMPROVED CEILING AS
THE WAVE PASSES IN THE LATE AFTERNOON AND WHICH IS THEN FOLLOWED BY
SOME POSSIBLE CONVECTIVE SHOWER ACTIVITY COMING IN FROM THE WEST
AFTER 00Z AS THE MAIN SHORTWAVE APPROACHES.
ELSEWHERE...GOOD VFR CONDITIONS THIS EVENING AS CONVECTIVE ACTIVITY
FORECAST BY HIGH-RES MODELS WAS OVERDONE. A WEAK SHORTWAVE EMBEDDED
IN SOUTHWESTERLY FLOW COULD LEAD TO SOME SHOWER ACTIVITY LATER
TONIGHT...BUT COVERAGE WOULD BE WIDELY SCATTERED. SOME RH INCREASE
AROUND THE 5000 FT LEVEL WITH BKN SKIES DUE TO THE PASSING SHORT
WAVE TOMORROW MORNING...MODELS SHOW AN INCREASE IN CONVECTIVE
ACTIVITY TOMORROW AFTERNOON AS A MORE SIGNIFICANT SHORTWAVE
APPROACHES FROM THE WEST. GFS HAS ACTIVITY BEGINNING EARLIER IN
AREAS TO THE SOUTH...AND MOST AREAS BY 0Z. SOME FOG IS POSSIBLE IN
LOW LYING AREAS...ESPECIALLY 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...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT HIGH 100% HIGH 97% HIGH 98% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 83% HIGH 100%
KAVL HIGH 100% MED 68% HIGH 81% HIGH 95%
KHKY HIGH 100% MED 75% HIGH 88% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 92% HIGH 100%
KAND HIGH 100% HIGH 91% HIGH 97% 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...WJM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
748 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 745 PM FRIDAY...AREA IS ENTIRELY CLEAR OF ANY RADAR ECHOES AT
THE MOMENT WITH LIGHT AND VARIABLE WINDS AND PARTLY CLOUD SKIES.
CONVECTIVE ACTIVITY INDICATED BY CAMS WAS OVERDONE BY THE MODELS.
CURRENT EXPECTATIONS ARE FOR NO PRECIP THROUGH 5Z AT LEAST. AFTER
5Z...A WEAK SHORTWAVE EMBEDDED IN THE SOUTHWESTERLY FLOW ALOFT MAY
KICK-OFF A FEW WIDELY SCATTERED AND WEAK SHOWERS...ESPECIALLY IN
EASTERN PARTS OF THE CWA WHICH HAS SLIGHTLY BETTER MOISTURE. A
BETTER CHANCE FOR PRECIPITATION WILL BE SATURDAY AFTERNOON AS THE
MAIN SHORTWAVE APPROACHES FROM THE WEST.
AS OF 510 PM 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 /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...GOOD VFR CONDITIONS THIS EVENING AS CONVECTIVE ACTIVITY
FORECAST BY HIGH-RES MODELS WAS OVERDONE. A WEAK SHORTWAVE EMBEDDED
IN SOUTHWESTERLY FLOW COULD LEAD TO SOME SHOWER ACTIVITY LATER
TONIGHT...BUT COVERAGE WOULD BE WIDELY SCATTERED. SOME RH INCREASE
AROUND THE 5000 FT LEVEL WITH BKN SKIES DUE TO THE PASSING SHORT
WAVE TOMORROW MORNING...THIS IS FOLLOWED BY AN IMPROVED CEILING AS
THE WAVE PASSES IN THE LATE AFTERNOON AND WHICH IS THEN FOLLOWED BY
SOME POSSIBLE CONVECTIVE SHOWER ACTIVITY COMING IN FROM THE WEST
AFTER 00Z AS THE MAIN SHORTWAVE APPROACHES.
ELSEWHERE...GOOD VFR CONDITIONS THIS EVENING AS CONVECTIVE ACTIVITY
FORECAST BY HIGH-RES MODELS WAS OVERDONE. A WEAK SHORTWAVE EMBEDDED
IN SOUTHWESTERLY FLOW COULD LEAD TO SOME SHOWER ACTIVITY LATER
TONIGHT...BUT COVERAGE WOULD BE WIDELY SCATTERED. SOME RH INCREASE
AROUND THE 5000 FT LEVEL WITH BKN SKIES DUE TO THE PASSING SHORT
WAVE TOMORROW MORNING...MODELS SHOW AN INCREASE IN CONVECTIVE
ACTIVITY TOMORROW AFTERNOON AS A MORE SIGNIFICANT SHORTWAVE
APPROACHES FROM THE WEST. GFS HAS ACTIVITY BEGINNING EARLIER IN
AREAS TO THE SOUTH...AND MOST AREAS BY 0Z. SOME FOG IS POSSIBLE IN
LOW LYING AREAS...ESPECIALLY 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...
23-05Z 05-11Z 11-17Z 17-18Z
KCLT HIGH 100% HIGH 100% HIGH 94% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 91%
KAVL HIGH 100% HIGH 83% HIGH 89% MED 75%
KHKY HIGH 100% HIGH 100% LOW 39% MED 75%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...WIMBERLEY/WJM
SHORT TERM...CDG
LONG TERM...LEV
AVIATION...WJM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
135 PM EDT THU AUG 20 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY
BRINGING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS. IN THE
FRONTS WAKE...SOME DRYING IS EXPECTED OVER THE WEEKEND. ANOTHER WEAK
FRONT APPROACHES THE CAROLINAS ON MONDAY WITH HIGH PRESSURE MOVING
OVER THE REGION BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 135 PM...CONVECTION BEGINNING ACROSS THE CWFA AND WILL ONLY
INCREASE IN COVERAGE THRU THE REST OF THE AFTERNOON. GOING FCST HAS
THIS COVERED WITH ONLY MINOR UPDATES NEEDED FOR CURRENT CONDITIONS.
AS OF 1040 AM...SKIES CLEARING OUT FROM WEST TO EAST ACROSS THE
AREA. HOWEVER...CU BEGINNING TO DEVELOP IN THE CLEARED AREA AS
HEATING BEGINS. EXPECT THE CU TO CONTINUE TO INCREASE THRU THE DAY.
STILL LOOKS LIKE ANOTHER ROUND OF AT LEAST SCT CONVECTION TODAY
GIVEN THE UNSTABLE ATMOSPHERE AND THE COLD FRONT APPROACHING FROM
THE NW. OLDER CAM GUIDANCE WAS SUGGESTING POSSIBLY LESS COVERAGE
TODAY. HOWEVER...LATEST RUNS SHOW GOOD COVERAGE...BUT DO SUGGEST NE
GA AND THE UPSTATE MAY STILL HAVE LOWER COVERAGE THAN NC. WILL NOT
ADJUST POP FOR THE AFTERNOON...BUT DID SLOW DEVELOPMENT GIVEN THE
LACK OF CURRENT COVERAGE AND PREVIOUS QUICK ONSET. STILL EXPECT
MODERATE INSTABILITY WITH EFFECTIVE SHEAR APPROACHING MODERATE
LEVELS AS WELL. DCAPE WILL NOT BE EXCEPTIONALLY HIGH...BUT LOOKS TO
BE OVER 500 J/KG. THEREFORE...SEVERE STORMS POSSIBLE AGAIN. WITH PW
VALUES APPROACHING 2 INCHES...ISOLATED FLOODING WILL ALSO BE
POSSIBLE. HIGHS WILL BE TRICKY...ESPECIALLY GIVEN THE MORNING
CLEARING...BUT CURRENT VALUES SHUD BE CLOSE.
AS OF 630 AM THURSDAY...ONLY ISOLATED SHOWERS CONTINUE FOR THE
UPDATE...SO HAVE REDUCED POPS SIGNIFICANTLY THROUGH THE MORNING. AS
MENTIONED BELOW...HIRES GUIDANCE CONTINUES TO NOT BE VERY EXCITED
ABOUT CONVECTIVE POTENTIAL THIS AFTERNOON THOUGH SYNOPTIC MODELS
CONTINUE TO PAINT CONVECTIVE PRECIP ACROSS THE AREA. WITH THIS
UNCERTAINTY AND GIVEN PERSISTENCE TRENDS...MADE ONLY MINOR
ADJUSTMENTS TO AFTERNOON POPS.
AS OF 230 AM THURSDAY...BENIGN CONDITIONS AT AFD TIME...BUT THIS
AFTER QUITE AN EVENTFUL EVENING YESTERDAY. WARM RAIN PROCESSES AND
TRAINING CELLS RESULTED IN ANOTHER 5+ INCHES OF RAIN ACROSS PORTIONS
OF UNION COUNTY NC WHERE SOME SIGNIFICANT FLASH FLOODING WAS
REPORTED. GOOSE CREEK REMAINS HIGH WITH ONE POINT STILL IN FLOOD AT
AFD TIME.
ONTO THE FORECAST...DEEP UPPER TROUGH STRETCHING DOWN THE
MISSISSIPPI WILL BEGIN TO LIFT INTO THE GREAT LAKES AND SOUTHEAST
CANADA TODAY...WITH AN OCCLUDED COLD FRONT PUSHING TOWARD THE
SOUTHERN APPALACHIANS. THE SOUTHERN EDGE OF THE FRONT IS PROGGED TO
PUSH THROUGH THE FORECAST AREA TONIGHT BUT WASH OUT QUICKLY.
DEWPOINTS BY SUNRISE FRIDAY WILL ACTUALLY DROP INTO THE UPPER 60S
ACROSS THE UPSTATE WITH SOME UPPER 50S IN THE MOUNTAINS. WE WILL
ALSO SEE LOW TEMPERATURES A COUPLE OF DEGREES COOLER THAN WE HAVE
BEEN EXPERIENCING LATELY...BUT THE DECREASE IN DEWPOINTS WILL NOT BE
QUITE QUICK ENOUGH TO BRING LOWS DOWN TO SEASONAL NORMALS JUST YET.
ANOTHER WEAK SHORTWAVE DIVING TOWARD THE OHIO VALLEY TONIGHT...WITH
A FAIRLY POTENT VORT LOBE...WILL SERVE TO PULL UP ADDITIONAL
MOISTURE AS SURFACE PATTERN TRANSITIONS TO HIGH PRESSURE.
BIGGEST CONCERN OF THE NEAR TERM WILL BE CHANCE OF ADDITIONAL
CONVECTION TODAY. WITH THE APPROACH AND PASSAGE OF THE COLD FRONT...
CERTAINLY THERE IS ENOUGH SYNOPTIC FORCING...AND WITH PW VALUES
REMAINING GENERALLY AT OR ABOVE 2 INCHES...WE SHOULD CONTINUE TO SEE
FAIRLY EFFICIENT RAIN PRODUCERS. NOT GOOD NEWS FOR FOLKS THAT
EXPERIENCED SOME SIGNIFICANT RAINFALL AMOUNTS AND RESULTING FLASH
FLOODING LAST NIGHT. LUCKILY SBCAPE VALUES GENERALLY REMAIN BELOW
1000 J/KG SO CONVECTIVE INTENSITY SHOULD NOT BE QUITE AS BAD AS
YESTERDAY. ALL THAT SAID...HI-RES GUIDANCE NOT PARTICULARLY
IMPRESSED WITH CONVECTIVE POTENTIAL FOR THIS AFTERNOON. HRRR ONLY
HAS ISOLATED CONVECTION AT BEST EVEN THROUGH 20Z. WRF NMM AND ARW
REFLECTIVITY GUIDANCE ON PAR WITH THE HRRR. WITH THAT...KEPT POPS AT
CHANCE AT BEST ACROSS THE UPSTATE AND MOST OF THE NC PIEDMONT...WITH
LIKELIES IN THE MOUNTAINS. CONFIDENCE NOT PARTICULARLY HIGH SO WILL
HAVE TO MONITOR THROUGH THE DAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 310 AM EDT THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH THE UPPER TROF LIFTING NE OF THE GREAT LAKES AS HEIGHTS
BEGIN TO RISE OVER THE SE REGION. THIS PATTERN WILL PERSIST INTO THE
MEDIUM RANGE WITH VARIOUS LOBES OF SHORTWAVE ENERGY APPROACHING THE
CWFA FROM THE WEST OVER THE WEEKEND. IN ADDITION...ANOTHER COMPACT
UPPER TROF WILL DIG DOWN OVER THE US/CANADA BORDER OVER THE WEEKEND
AND MOVE ACROSS THE GREAT LAKES BY THE START OF THE MEDIUM RANGE.
ON FRIDAY...THE SFC HIGH GRADUALLY SLIDES EASTWARD AND THEN NE THRU
THE DAY AND EVENING WITH LOW LVL DRYING AS THE BNDY LAYER FLOW
BECOMES MORE NLY. THE GFS SOLUTION CONTINUES TO BE THE DRIEST MODEL
OVERALL WITH THE NAM BEING THE WETTEST. REGARDLESS OF MODEL
CHOICE...THE TREND IS FOR DRIER PROFILES AND LESS INFLUENCE FROM THE
GULF AS WE MOVE INTO SAT. ON SATURDAY...THE SFC HIGH SLIDES A BIT
FARTHER NE AND UP OVER NEW ENGLAND AS SOME WEAK WEDGING APPEARS TO
BRIEFLY DEVELOP OVER THE CAROLINAS. ANY WEDGING IS EXPECTED TO BE
SHORT LIVED WITH THE LOW LVL FLOW BECOMING WEAKER SAT AFTERNOON AND
EVENING. THE PERIOD ENDS EARLY SUN WITH THE NEXT COLD FRONT STILL
WELL TO OUR WEST AND MOSTLY LIGHT AND VRB FLOW OVER THE CWFA. AS FOR
THE SENSIBLE FCST...THE BEST CHANCES FOR ADDITIONAL PRECIP WILL BE
ON FRI WITH LOWER CHANCES FOR SAT AND SUN. MAX TEMPS WILL STRUGGLE
TO GET REACH CLIMO WHILE MIN TEMPS SHOULD START OUT ABOUT A CATEGORY
ABOVE AND COOL AROUND 2 TO 4 DEGREES THRU THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 255 AM EDT THURSDAY...THE MEDIUM RANGE FCST BEGINS AT 12Z ON
SUNDAY WITH FLAT UPPER RIDGING OVER THE GULF OF MEX AND ANOTHER
UPPER TROF DIGGING DOWN OVER MINNESOTA AND THE WESTERN GREAT LAKES.
OVER THE REMAINDER OF THE PERIOD...THE LONG RANGE MODELS GRADUALLY
MOVE THE TROF EASTWARD AND EVENTUALLY LIFT IT NE OF NEW ENGLAND. THE
LATEST 00Z RUN OF THE GFS REMAINS FASTER WITH THE TROFS PROGRESSION
COMPARED TO THE ECMWF...HOWEVER THEY ARE MORE SIMILAR THAN BEFORE
WITH BOTH MODELS DEVELOPING A CLOSED LOW BY EARLY NEXT WEEK. THE
UPPER RIDGING WILL REAMPLIFY OVER THE CENTRAL CONUS IN THE TROFS
WAKE BY MID TO LATE NEXT WEEK WITH THE GFS STILL QUITE A BIT MORE
ROBUST WITH THE RIDGE. AT THE SFC...LINGERING HIGH PRESSURE WILL BE
IN PLACE OVER THE REGION ON SUNDAY. ANOTHER COLD FRONT WILL APPROACH
THE CWFA LATE SUN/EARLY MON AND MOVE ACROSS THE CWFA DURING THE DAY.
THE GFS CONTINUES TO BE FASTER AND A BIT DRIER OVERALL WITH THE
FROPA COMPARED TO THE ECMWF...YET BOTH MODELS ARE LOOKING PRETTY DRY
AT THIS POINT. ANOTHER HIGH WILL PUSH INTO THE REGION BEHIND THE
FRONT ON TUES AND LINGER THRU THE REMAINDER OF THE MEDIUM RANGE.
AS FOR THE SENSIBLE WX...NO SIGNIFICANT CHANGES WERE NEEDED WITH A
SLIGHT TO SOLID CHANCE POP EACH DAY AND TEMPS JUST ABOVE NORMAL FOR
LATE AUGUST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...CONVECTION ALREADY DEVELOPING IN THE GENERAL AREA...SO
WILL KEEP THE TEMPO FOR TSRA AT 18Z-22Z. DID NOT ADD ANY MENTION
AFTER...BUT IT IS CERTAINLY POSSIBLE THEY COULD LINGER INTO THE
EARLY EVENING. OTHERWISE...FCST GENERALLY ON TRACK WITH DEVELOPING
LOW VFR CU WHICH BECOME STRATOCU DURING THE EVENING AND LINGER INTO
THE DAY FRIDAY. WITH THE COLD FRONT COMING THRU THIS EVENING...
WINDS WILL SHIFT FROM SW TO WNW THEN N THRU THE EVENING WITH NE WIND
FRI MORN. THIS WILL KEEP FOG AT BAY...AND LACK OF VERY LOW LEVEL
MOISTURE SHUD KEEP CIGS AT LOW VFR.
ELSEWHERE...SIMILAR TRENDS TO KCLT...BUT SLIGHTLY DIFFERENT WIND
SHIFT TIMING. ALSO...KAVL SEEMS TO HAVE THE BEST CHC OF ANY
RESTRICTIONS OVERNIGHT. HAVE GONE WITH MVFR FOG AND TEMPO IFR FOG
AND CIGS. COULD BE LESS IN THE WAY OF FOG AND MORE STRATUS...BUT AT
LEAST IFR LOOKS LIKELY. COULD BE ISOLATED TO LOW END SCT CONVECTION
DEVELOPING FRI...BUT CHC TOO LOW AND TIMING TOO UNCERTAIN TO INCLUDE.
OUTLOOK...DRY HIGH PRESSURE BUILDING IN FROM THE NORTH WILL LIMIT
RESTRICTIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL LOW 57% LOW 55% HIGH 100% HIGH 83%
KHKY LOW 57% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...RWH/TDP
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1047 AM EDT THU AUG 20 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY
BRINGING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS. IN THE
FRONTS WAKE...SOME DRYING IS EXPECTED OVER THE WEEKEND. ANOTHER WEAK
FRONT APPROACHES THE CAROLINAS ON MONDAY WITH HIGH PRESSURE MOVING
OVER THE REGION BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1040 AM...SKIES CLEARING OUT FROM WEST TO EAST ACROSS THE
AREA. HOWEVER...CU BEGINNING TO DEVELOP IN THE CLEARED AREA AS
HEATING BEGINS. EXPECT THE CU TO CONTINUE TO INCREASE THRU THE DAY.
STILL LOOKS LIKE ANOTHER ROUND OF AT LEAST SCT CONVECTION TODAY
GIVEN THE UNSTABLE ATMOSPHERE AND THE COLD FRONT APPROACHING FROM
THE NW. OLDER CAM GUIDANCE WAS SUGGESTING POSSIBLY LESS COVERAGE
TODAY. HOWEVER...LATEST RUNS SHOW GOOD COVERAGE...BUT DO SUGGEST NE
GA AND THE UPSTATE MAY STILL HAVE LOWER COVERAGE THAN NC. WILL NOT
ADJUST POP FOR THE AFTERNOON...BUT DID SLOW DEVELOPMENT GIVEN THE
LACK OF CURRENT COVERAGE AND PREVIOUS QUICK ONSET. STILL EXPECT
MODERATE INSTABILITY WITH EFFECTIVE SHEAR APPROACHING MODERATE
LEVELS AS WELL. DCAPE WILL NOT BE EXCEPTIONALLY HIGH...BUT LOOKS TO
BE OVER 500 J/KG. THEREFORE...SEVERE STORMS POSSIBLE AGAIN. WITH PW
VALUES APPROACHING 2 INCHES...ISOLATED FLOODING WILL ALSO BE
POSSIBLE. HIGHS WILL BE TRICKY...ESPECIALLY GIVEN THE MORNING
CLEARING...BUT CURRENT VALUES SHUD BE CLOSE.
AS OF 630 AM THURSDAY...ONLY ISOLATED SHOWERS CONTINUE FOR THE
UPDATE...SO HAVE REDUCED POPS SIGNIFICANTLY THROUGH THE MORNING. AS
MENTIONED BELOW...HIRES GUIDANCE CONTINUES TO NOT BE VERY EXCITED
ABOUT CONVECTIVE POTENTIAL THIS AFTERNOON THOUGH SYNOPTIC MODELS
CONTINUE TO PAINT CONVECTIVE PRECIP ACROSS THE AREA. WITH THIS
UNCERTAINTY AND GIVEN PERSISTENCE TRENDS...MADE ONLY MINOR
ADJUSTMENTS TO AFTERNOON POPS.
AS OF 230 AM THURSDAY...BENIGN CONDITIONS AT AFD TIME...BUT THIS
AFTER QUITE AN EVENTFUL EVENING YESTERDAY. WARM RAIN PROCESSES AND
TRAINING CELLS RESULTED IN ANOTHER 5+ INCHES OF RAIN ACROSS PORTIONS
OF UNION COUNTY NC WHERE SOME SIGNIFICANT FLASH FLOODING WAS
REPORTED. GOOSE CREEK REMAINS HIGH WITH ONE POINT STILL IN FLOOD AT
AFD TIME.
ONTO THE FORECAST...DEEP UPPER TROUGH STRETCHING DOWN THE
MISSISSIPPI WILL BEGIN TO LIFT INTO THE GREAT LAKES AND SOUTHEAST
CANADA TODAY...WITH AN OCCLUDED COLD FRONT PUSHING TOWARD THE
SOUTHERN APPALACHIANS. THE SOUTHERN EDGE OF THE FRONT IS PROGGED TO
PUSH THROUGH THE FORECAST AREA TONIGHT BUT WASH OUT QUICKLY.
DEWPOINTS BY SUNRISE FRIDAY WILL ACTUALLY DROP INTO THE UPPER 60S
ACROSS THE UPSTATE WITH SOME UPPER 50S IN THE MOUNTAINS. WE WILL
ALSO SEE LOW TEMPERATURES A COUPLE OF DEGREES COOLER THAN WE HAVE
BEEN EXPERIENCING LATELY...BUT THE DECREASE IN DEWPOINTS WILL NOT BE
QUITE QUICK ENOUGH TO BRING LOWS DOWN TO SEASONAL NORMALS JUST YET.
ANOTHER WEAK SHORTWAVE DIVING TOWARD THE OHIO VALLEY TONIGHT...WITH
A FAIRLY POTENT VORT LOBE...WILL SERVE TO PULL UP ADDITIONAL
MOISTURE AS SURFACE PATTERN TRANSITIONS TO HIGH PRESSURE.
BIGGEST CONCERN OF THE NEAR TERM WILL BE CHANCE OF ADDITIONAL
CONVECTION TODAY. WITH THE APPROACH AND PASSAGE OF THE COLD FRONT...
CERTAINLY THERE IS ENOUGH SYNOPTIC FORCING...AND WITH PW VALUES
REMAINING GENERALLY AT OR ABOVE 2 INCHES...WE SHOULD CONTINUE TO SEE
FAIRLY EFFICIENT RAIN PRODUCERS. NOT GOOD NEWS FOR FOLKS THAT
EXPERIENCED SOME SIGNIFICANT RAINFALL AMOUNTS AND RESULTING FLASH
FLOODING LAST NIGHT. LUCKILY SBCAPE VALUES GENERALLY REMAIN BELOW
1000 J/KG SO CONVECTIVE INTENSITY SHOULD NOT BE QUITE AS BAD AS
YESTERDAY. ALL THAT SAID...HI-RES GUIDANCE NOT PARTICULARLY
IMPRESSED WITH CONVECTIVE POTENTIAL FOR THIS AFTERNOON. HRRR ONLY
HAS ISOLATED CONVECTION AT BEST EVEN THROUGH 20Z. WRF NMM AND ARW
REFLECTIVITY GUIDANCE ON PAR WITH THE HRRR. WITH THAT...KEPT POPS AT
CHANCE AT BEST ACROSS THE UPSTATE AND MOST OF THE NC PIEDMONT...WITH
LIKELIES IN THE MOUNTAINS. CONFIDENCE NOT PARTICULARLY HIGH SO WILL
HAVE TO MONITOR THROUGH THE DAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 310 AM EDT THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH THE UPPER TROF LIFTING NE OF THE GREAT LAKES AS HEIGHTS
BEGIN TO RISE OVER THE SE REGION. THIS PATTERN WILL PERSIST INTO THE
MEDIUM RANGE WITH VARIOUS LOBES OF SHORTWAVE ENERGY APPROACHING THE
CWFA FROM THE WEST OVER THE WEEKEND. IN ADDITION...ANOTHER COMPACT
UPPER TROF WILL DIG DOWN OVER THE US/CANADA BORDER OVER THE WEEKEND
AND MOVE ACROSS THE GREAT LAKES BY THE START OF THE MEDIUM RANGE.
ON FRIDAY...THE SFC HIGH GRADUALLY SLIDES EASTWARD AND THEN NE THRU
THE DAY AND EVENING WITH LOW LVL DRYING AS THE BNDY LAYER FLOW
BECOMES MORE NLY. THE GFS SOLUTION CONTINUES TO BE THE DRIEST MODEL
OVERALL WITH THE NAM BEING THE WETTEST. REGARDLESS OF MODEL
CHOICE...THE TREND IS FOR DRIER PROFILES AND LESS INFLUENCE FROM THE
GULF AS WE MOVE INTO SAT. ON SATURDAY...THE SFC HIGH SLIDES A BIT
FARTHER NE AND UP OVER NEW ENGLAND AS SOME WEAK WEDGING APPEARS TO
BRIEFLY DEVELOP OVER THE CAROLINAS. ANY WEDGING IS EXPECTED TO BE
SHORT LIVED WITH THE LOW LVL FLOW BECOMING WEAKER SAT AFTERNOON AND
EVENING. THE PERIOD ENDS EARLY SUN WITH THE NEXT COLD FRONT STILL
WELL TO OUR WEST AND MOSTLY LIGHT AND VRB FLOW OVER THE CWFA. AS FOR
THE SENSIBLE FCST...THE BEST CHANCES FOR ADDITIONAL PRECIP WILL BE
ON FRI WITH LOWER CHANCES FOR SAT AND SUN. MAX TEMPS WILL STRUGGLE
TO GET REACH CLIMO WHILE MIN TEMPS SHOULD START OUT ABOUT A CATEGORY
ABOVE AND COOL AROUND 2 TO 4 DEGREES THRU THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 255 AM EDT THURSDAY...THE MEDIUM RANGE FCST BEGINS AT 12Z ON
SUNDAY WITH FLAT UPPER RIDGING OVER THE GULF OF MEX AND ANOTHER
UPPER TROF DIGGING DOWN OVER MINNESOTA AND THE WESTERN GREAT LAKES.
OVER THE REMAINDER OF THE PERIOD...THE LONG RANGE MODELS GRADUALLY
MOVE THE TROF EASTWARD AND EVENTUALLY LIFT IT NE OF NEW ENGLAND. THE
LATEST 00Z RUN OF THE GFS REMAINS FASTER WITH THE TROFS PROGRESSION
COMPARED TO THE ECMWF...HOWEVER THEY ARE MORE SIMILAR THAN BEFORE
WITH BOTH MODELS DEVELOPING A CLOSED LOW BY EARLY NEXT WEEK. THE
UPPER RIDGING WILL REAMPLIFY OVER THE CENTRAL CONUS IN THE TROFS
WAKE BY MID TO LATE NEXT WEEK WITH THE GFS STILL QUITE A BIT MORE
ROBUST WITH THE RIDGE. AT THE SFC...LINGERING HIGH PRESSURE WILL BE
IN PLACE OVER THE REGION ON SUNDAY. ANOTHER COLD FRONT WILL APPROACH
THE CWFA LATE SUN/EARLY MON AND MOVE ACROSS THE CWFA DURING THE DAY.
THE GFS CONTINUES TO BE FASTER AND A BIT DRIER OVERALL WITH THE
FROPA COMPARED TO THE ECMWF...YET BOTH MODELS ARE LOOKING PRETTY DRY
AT THIS POINT. ANOTHER HIGH WILL PUSH INTO THE REGION BEHIND THE
FRONT ON TUES AND LINGER THRU THE REMAINDER OF THE MEDIUM RANGE.
AS FOR THE SENSIBLE WX...NO SIGNIFICANT CHANGES WERE NEEDED WITH A
SLIGHT TO SOLID CHANCE POP EACH DAY AND TEMPS JUST ABOVE NORMAL FOR
LATE AUGUST.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT...LOW CLOUDS CLEARED QUICKER THAN EXPECTED THIS MORNING...
BUT EXPECT MVFR CU TO DEVELOP WITH THE EARLIER THAN EXPECTED
HEATING. STILL EXPECT AFTERNOON TSRA...BUT THE CURRENT TIMING MAY
NEED TO BE ADJUSTED AS DEVELOPMENT HAS BEEN SLOWER. WINDS GENERALLY
SW 5KT OR LESS THROUGH MOST OF THE PERIOD...BUT SHIFTING NW AS THE
FRONT APPROACHES AND MOVES THROUGH. CURRENT TIMING IS AROUND 05Z.
FOR NOW...VFR FOR FRIDAY MORNING BUT HIGHLY DEPENDENT ON CONVECTIVE
COVERAGE AND AMOUNT OF PRECIP THIS AFTERNOON/EVENING.
ELSEWHERE...SIMILAR TRENDS TO KCLT...BUT QUICKER ONSET OF MVFR CU.
WILL LIKELY SEE ANOTHER ROUND OF LOW CIGS FRIDAY MORNING...BUT
ACTUAL RESTRICTIONS WILL DEPEND ON CONVECTIVE COVERAGE AND AMOUNT OF
PRECIP RECEIVED THIS AFTERNOON AND EVENING. INTRODUCED RESTRICTIONS
AT KAVL BUT OTHERWISE WILL HAVE TO MONITOR TRENDS FOR TODAY.
OUTLOOK...LINGERING LOW LEVEL MOISTURE MAY RESULT IN RESTRICTIONS IN
FOG/STRATUS EARLY FRIDAY. DRY HIGH PRESSURE BUILDING IN FROM THE
NORTH WILL LIMIT RESTRICTIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-12Z
KCLT MED 74% HIGH 100% HIGH 100% HIGH 100%
KGSP MED 72% HIGH 100% HIGH 100% HIGH 100%
KAVL LOW 56% HIGH 88% HIGH 97% HIGH 81%
KHKY MED 68% HIGH 100% HIGH 95% MED 70%
KGMU MED 68% HIGH 100% HIGH 100% HIGH 100%
KAND MED 74% 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...JPT
NEAR TERM...RWH/TDP
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...RWH/TDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
736 AM EDT THU AUG 20 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY
BRINGING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS. IN THE
FRONTS WAKE...SOME DRYING IS EXPECTED OVER THE WEEKEND. ANOTHER WEAK
FRONT APPROACHES THE CAROLINAS ON MONDAY WITH HIGH PRESSURE MOVING
OVER THE REGION BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...ONLY ISOLATED SHOWERS CONTINUE FOR THE
UPDATE...SO HAVE REDUCED POPS SIGNIFICANTLY THROUGH THE MORNING. AS
MENTIONED BELOW...HIRES GUIDANCE CONTINUES TO NOT BE VERY EXCITED
ABOUT CONVECTIVE POTENTIAL THIS AFTERNOON THOUGH SYNOPTIC MODELS
CONTINUE TO PAINT CONVECTIVE PRECIP ACROSS THE AREA. WITH THIS
UNCERTAINTY AND GIVEN PERSISTENCE TRENDS...MADE ONLY MINOR
ADJUSTMENTS TO AFTERNOON POPS.
AS OF 230 AM THURSDAY...BENIGN CONDITIONS AT AFD TIME...BUT THIS
AFTER QUITE AN EVENTFUL EVENING YESTERDAY. WARM RAIN PROCESSES AND
TRAINING CELLS RESULTED IN ANOTHER 5+ INCHES OF RAIN ACROSS PORTIONS
OF UNION COUNTY NC WHERE SOME SIGNIFICANT FLASH FLOODING WAS
REPORTED. GOOSE CREEK REMAINS HIGH WITH ONE POINT STILL IN FLOOD AT
AFD TIME.
ONTO THE FORECAST...DEEP UPPER TROUGH STRETCHING DOWN THE
MISSISSIPPI WILL BEGIN TO LIFT INTO THE GREAT LAKES AND SOUTHEAST
CANADA TODAY...WITH AN OCCLUDED COLD FRONT PUSHING TOWARD THE
SOUTHERN APPALACHIANS. THE SOUTHERN EDGE OF THE FRONT IS PROGGED TO
PUSH THROUGH THE FORECAST AREA TONIGHT BUT WASH OUT QUICKLY.
DEWPOINTS BY SUNRISE FRIDAY WILL ACTUALLY DROP INTO THE UPPER 60S
ACROSS THE UPSTATE WITH SOME UPPER 50S IN THE MOUNTAINS. WE WILL
ALSO SEE LOW TEMPERATURES A COUPLE OF DEGREES COOLER THAN WE HAVE
BEEN EXPERIENCING LATELY...BUT THE DECREASE IN DEWPOINTS WILL NOT BE
QUITE QUICK ENOUGH TO BRING LOWS DOWN TO SEASONAL NORMALS JUST YET.
ANOTHER WEAK SHORTWAVE DIVING TOWARD THE OHIO VALLEY TONIGHT...WITH
A FAIRLY POTENT VORT LOBE...WILL SERVE TO PULL UP ADDITIONAL
MOISTURE AS SURFACE PATTERN TRANSITIONS TO HIGH PRESSURE.
BIGGEST CONCERN OF THE NEAR TERM WILL BE CHANCE OF ADDITIONAL
CONVECTION TODAY. WITH THE APPROACH AND PASSAGE OF THE COLD FRONT...
CERTAINLY THERE IS ENOUGH SYNOPTIC FORCING...AND WITH PW VALUES
REMAINING GENERALLY AT OR ABOVE 2 INCHES...WE SHOULD CONTINUE TO SEE
FAIRLY EFFICIENT RAIN PRODUCERS. NOT GOOD NEWS FOR FOLKS THAT
EXPERIENCED SOME SIGNIFICANT RAINFALL AMOUNTS AND RESULTING FLASH
FLOODING LAST NIGHT. LUCKILY SBCAPE VALUES GENERALLY REMAIN BELOW
1000 J/KG SO CONVECTIVE INTENSITY SHOULD NOT BE QUITE AS BAD AS
YESTERDAY. ALL THAT SAID...HI-RES GUIDANCE NOT PARTICULARLY
IMPRESSED WITH CONVECTIVE POTENTIAL FOR THIS AFTERNOON. HRRR ONLY
HAS ISOLATED CONVECTION AT BEST EVEN THROUGH 20Z. WRF NMM AND ARW
REFLECTIVITY GUIDANCE ON PAR WITH THE HRRR. WITH THAT...KEPT POPS AT
CHANCE AT BEST ACROSS THE UPSTATE AND MOST OF THE NC PIEDMONT...WITH
LIKELIES IN THE MOUNTAINS. CONFIDENCE NOT PARTICULARLY HIGH SO WILL
HAVE TO MONITOR THROUGH THE DAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 310 AM EDT THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH THE UPPER TROF LIFTING NE OF THE GREAT LAKES AS HEIGHTS
BEGIN TO RISE OVER THE SE REGION. THIS PATTERN WILL PERSIST INTO THE
MEDIUM RANGE WITH VARIOUS LOBES OF SHORTWAVE ENERGY APPROACHING THE
CWFA FROM THE WEST OVER THE WEEKEND. IN ADDITION...ANOTHER COMPACT
UPPER TROF WILL DIG DOWN OVER THE US/CANADA BORDER OVER THE WEEKEND
AND MOVE ACROSS THE GREAT LAKES BY THE START OF THE MEDIUM RANGE.
ON FRIDAY...THE SFC HIGH GRADUALLY SLIDES EASTWARD AND THEN NE THRU
THE DAY AND EVENING WITH LOW LVL DRYING AS THE BNDY LAYER FLOW
BECOMES MORE NLY. THE GFS SOLUTION CONTINUES TO BE THE DRIEST MODEL
OVERALL WITH THE NAM BEING THE WETTEST. REGARDLESS OF MODEL
CHOICE...THE TREND IS FOR DRIER PROFILES AND LESS INFLUENCE FROM THE
GULF AS WE MOVE INTO SAT. ON SATURDAY...THE SFC HIGH SLIDES A BIT
FARTHER NE AND UP OVER NEW ENGLAND AS SOME WEAK WEDGING APPEARS TO
BRIEFLY DEVELOP OVER THE CAROLINAS. ANY WEDGING IS EXPECTED TO BE
SHORT LIVED WITH THE LOW LVL FLOW BECOMING WEAKER SAT AFTERNOON AND
EVENING. THE PERIOD ENDS EARLY SUN WITH THE NEXT COLD FRONT STILL
WELL TO OUR WEST AND MOSTLY LIGHT AND VRB FLOW OVER THE CWFA. AS FOR
THE SENSIBLE FCST...THE BEST CHANCES FOR ADDITIONAL PRECIP WILL BE
ON FRI WITH LOWER CHANCES FOR SAT AND SUN. MAX TEMPS WILL STRUGGLE
TO GET REACH CLIMO WHILE MIN TEMPS SHOULD START OUT ABOUT A CATEGORY
ABOVE AND COOL AROUND 2 TO 4 DEGREES THRU THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 255 AM EDT THURSDAY...THE MEDIUM RANGE FCST BEGINS AT 12Z ON
SUNDAY WITH FLAT UPPER RIDGING OVER THE GULF OF MEX AND ANOTHER
UPPER TROF DIGGING DOWN OVER MINNESOTA AND THE WESTERN GREAT LAKES.
OVER THE REMAINDER OF THE PERIOD...THE LONG RANGE MODELS GRADUALLY
MOVE THE TROF EASTWARD AND EVENTUALLY LIFT IT NE OF NEW ENGLAND. THE
LATEST 00Z RUN OF THE GFS REMAINS FASTER WITH THE TROFS PROGRESSION
COMPARED TO THE ECMWF...HOWEVER THEY ARE MORE SIMILAR THAN BEFORE
WITH BOTH MODELS DEVELOPING A CLOSED LOW BY EARLY NEXT WEEK. THE
UPPER RIDGING WILL REAMPLIFY OVER THE CENTRAL CONUS IN THE TROFS
WAKE BY MID TO LATE NEXT WEEK WITH THE GFS STILL QUITE A BIT MORE
ROBUST WITH THE RIDGE. AT THE SFC...LINGERING HIGH PRESSURE WILL BE
IN PLACE OVER THE REGION ON SUNDAY. ANOTHER COLD FRONT WILL APPROACH
THE CWFA LATE SUN/EARLY MON AND MOVE ACROSS THE CWFA DURING THE DAY.
THE GFS CONTINUES TO BE FASTER AND A BIT DRIER OVERALL WITH THE
FROPA COMPARED TO THE ECMWF...YET BOTH MODELS ARE LOOKING PRETTY DRY
AT THIS POINT. ANOTHER HIGH WILL PUSH INTO THE REGION BEHIND THE
FRONT ON TUES AND LINGER THRU THE REMAINDER OF THE MEDIUM RANGE.
AS FOR THE SENSIBLE WX...NO SIGNIFICANT CHANGES WERE NEEDED WITH A
SLIGHT TO SOLID CHANCE POP EACH DAY AND TEMPS JUST ABOVE NORMAL FOR
LATE AUGUST.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AT KCLT...SEEING QUITE A BIT OF IFR CIGS AROUND CLT SO WILL START
THE TAF WITH MVFR TEMPO IFR FOR A COUPLE OF HOURS. SLOW LIFTING
TREND THROUGH THE MORNING BUT SHOULD BE VFR AROUND 15Z OR SO. BEST
TIMING FOR AFTERNOON TSRA IS 18-22Z SO INCLUDED TEMPO FOR THAT.
WINDS GENERALLY SW 5KT OR LESS THROUGH MOST OF THE PERIOD...BUT
SHIFTING NW AS THE FRONT APPROACHES AND MOVES THROUGH. CURRENT
TIMING IS AROUND 05Z. FOR NOW...VFR FOR FRIDAY MORNING BUT HIGHLY
DEPENDENT ON CONVECTIVE COVERAGE AND AMOUNT OF PRECIP THIS
AFTERNOON/EVENING.
ELSEWHERE...OVERALL SIMILAR TREND TO KCLT BUT WITH SLOWER LIFTING TO
CIGS THIS MORNING. IN ADDITION TO TEMPO TSRA 18-22Z AT ALL SITES...
WENT VCTS FOR KAVL/KHKY AS THE FRONT APPROACHES. WILL LIKELY SEE
ANOTHER ROUND OF LOW CIGS FRIDAY MORNING...BUT ACTUAL RESTRICTIONS
WILL DEPEND ON CONVECTIVE COVERAGE AND AMOUNT OF PRECIP RECEIVED
THIS AFTERNOON AND EVENING. INTRODUCED RESTRICTIONS AT KAVL BUT
OTHERWISE WILL HAVE TO MONITOR TRENDS FOR TODAY.
OUTLOOK...LINGERING LOW LEVEL MOISTURE MAY RESULT IN RESTRICTIONS IN
FOG/STRATUS EARLY FRIDAY. DRY HIGH PRESSURE BUILDING IN FROM THE
NORTH WILL LIMIT RESTRICTIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-06Z
KCLT MED 78% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 83% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 78% LOW 55% LOW 55% HIGH 93%
KHKY HIGH 89% MED 60% HIGH 100% HIGH 83%
KGMU MED 64% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 83% 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...JPT
NEAR TERM...TDP
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
453 AM EDT THU AUG 20 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY
BRINGING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS. IN THE
FRONTS WAKE...SOME DRYING IS EXPECTED OVER THE WEEKEND. ANOTHER WEAK
FRONT APPROACHES THE CAROLINAS ON MONDAY WITH HIGH PRESSURE MOVING
OVER THE REGION BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM THURSDAY...BENIGN CONDITIONS AT AFD TIME...BUT THIS
AFTER QUITE AN EVENTFUL EVENING YESTERDAY. WARM RAIN PROCESSES AND
TRAINING CELLS RESULTED IN ANOTHER 5+ INCHES OF RAIN ACROSS PORTIONS
OF UNION COUNTY NC WHERE SOME SIGNIFICANT FLASH FLOODING WAS
REPORTED. GOOSE CREEK REMAINS HIGH WITH ONE POINT STILL IN FLOOD AT
AFD TIME.
ONTO THE FORECAST...DEEP UPPER TROUGH STRETCHING DOWN THE
MISSISSIPPI WILL BEGIN TO LIFT INTO THE GREAT LAKES AND SOUTHEAST
CANADA TODAY...WITH AN OCCLUDED COLD FRONT PUSHING TOWARD THE
SOUTHERN APPALACHIANS. THE SOUTHERN EDGE OF THE FRONT IS PROGGED TO
PUSH THROUGH THE FORECAST AREA TONIGHT BUT WASH OUT QUICKLY.
DEWPOINTS BY SUNRISE FRIDAY WILL ACTUALLY DROP INTO THE UPPER 60S
ACROSS THE UPSTATE WITH SOME UPPER 50S IN THE MOUNTAINS. WE WILL
ALSO SEE LOW TEMPERATURES A COUPLE OF DEGREES COOLER THAN WE HAVE
BEEN EXPERIENCING LATELY...BUT THE DECREASE IN DEWPOINTS WILL NOT BE
QUITE QUICK ENOUGH TO BRING LOWS DOWN TO SEASONAL NORMALS JUST YET.
ANOTHER WEAK SHORTWAVE DIVING TOWARD THE OHIO VALLEY TONIGHT...WITH
A FAIRLY POTENT VORT LOBE...WILL SERVE TO PULL UP ADDITIONAL
MOISTURE AS SURFACE PATTERN TRANSITIONS TO HIGH PRESSURE.
BIGGEST CONCERN OF THE NEAR TERM WILL BE CHANCE OF ADDITIONAL
CONVECTION TODAY. WITH THE APPROACH AND PASSAGE OF THE COLD FRONT...
CERTAINLY THERE IS ENOUGH SYNOPTIC FORCING...AND WITH PW VALUES
REMAINING GENERALLY AT OR ABOVE 2 INCHES...WE SHOULD CONTINUE TO SEE
FAIRLY EFFICIENT RAIN PRODUCERS. NOT GOOD NEWS FOR FOLKS THAT
EXPERIENCED SOME SIGNIFICANT RAINFALL AMOUNTS AND RESULTING FLASH
FLOODING LAST NIGHT. LUCKILY SBCAPE VALUES GENERALLY REMAIN BELOW
1000 J/KG SO CONVECTIVE INTENSITY SHOULD NOT BE QUITE AS BAD AS
YESTERDAY. ALL THAT SAID...HI-RES GUIDANCE NOT PARTICULARLY
IMPRESSED WITH CONVECTIVE POTENTIAL FOR THIS AFTERNOON. HRRR ONLY
HAS ISOLATED CONVECTION AT BEST EVEN THROUGH 20Z. WRF NMM AND ARW
REFLECTIVITY GUIDANCE ON PAR WITH THE HRRR. WITH THAT...KEPT POPS AT
CHANCE AT BEST ACROSS THE UPSTATE AND MOST OF THE NC PIEDMONT...WITH
LIKELIES IN THE MOUNTAINS. CONFIDENCE NOT PARTICULARLY HIGH SO WILL
HAVE TO MONITOR THROUGH THE DAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 310 AM EDT THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH THE UPPER TROF LIFTING NE OF THE GREAT LAKES AS HEIGHTS
BEGIN TO RISE OVER THE SE REGION. THIS PATTERN WILL PERSIST INTO THE
MEDIUM RANGE WITH VARIOUS LOBES OF SHORTWAVE ENERGY APPROACHING THE
CWFA FROM THE WEST OVER THE WEEKEND. IN ADDITION...ANOTHER COMPACT
UPPER TROF WILL DIG DOWN OVER THE US/CANADA BORDER OVER THE WEEKEND
AND MOVE ACROSS THE GREAT LAKES BY THE START OF THE MEDIUM RANGE.
ON FRIDAY...THE SFC HIGH GRADUALLY SLIDES EASTWARD AND THEN NE THRU
THE DAY AND EVENING WITH LOW LVL DRYING AS THE BNDY LAYER FLOW
BECOMES MORE NLY. THE GFS SOLUTION CONTINUES TO BE THE DRIEST MODEL
OVERALL WITH THE NAM BEING THE WETTEST. REGARDLESS OF MODEL
CHOICE...THE TREND IS FOR DRIER PROFILES AND LESS INFLUENCE FROM THE
GULF AS WE MOVE INTO SAT. ON SATURDAY...THE SFC HIGH SLIDES A BIT
FARTHER NE AND UP OVER NEW ENGLAND AS SOME WEAK WEDGING APPEARS TO
BRIEFLY DEVELOP OVER THE CAROLINAS. ANY WEDGING IS EXPECTED TO BE
SHORT LIVED WITH THE LOW LVL FLOW BECOMING WEAKER SAT AFTERNOON AND
EVENING. THE PERIOD ENDS EARLY SUN WITH THE NEXT COLD FRONT STILL
WELL TO OUR WEST AND MOSTLY LIGHT AND VRB FLOW OVER THE CWFA. AS FOR
THE SENSIBLE FCST...THE BEST CHANCES FOR ADDITIONAL PRECIP WILL BE
ON FRI WITH LOWER CHANCES FOR SAT AND SUN. MAX TEMPS WILL STRUGGLE
TO GET REACH CLIMO WHILE MIN TEMPS SHOULD START OUT ABOUT A CATEGORY
ABOVE AND COOL AROUND 2 TO 4 DEGREES THRU THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 255 AM EDT THURSDAY...THE MEDIUM RANGE FCST BEGINS AT 12Z ON
SUNDAY WITH FLAT UPPER RIDGING OVER THE GULF OF MEX AND ANOTHER
UPPER TROF DIGGING DOWN OVER MINNESOTA AND THE WESTERN GREAT LAKES.
OVER THE REMAINDER OF THE PERIOD...THE LONG RANGE MODELS GRADUALLY
MOVE THE TROF EASTWARD AND EVENTUALLY LIFT IT NE OF NEW ENGLAND. THE
LATEST 00Z RUN OF THE GFS REMAINS FASTER WITH THE TROFS PROGRESSION
COMPARED TO THE ECMWF...HOWEVER THEY ARE MORE SIMILAR THAN BEFORE
WITH BOTH MODELS DEVELOPING A CLOSED LOW BY EARLY NEXT WEEK. THE
UPPER RIDGING WILL REAMPLIFY OVER THE CENTRAL CONUS IN THE TROFS
WAKE BY MID TO LATE NEXT WEEK WITH THE GFS STILL QUITE A BIT MORE
ROBUST WITH THE RIDGE. AT THE SFC...LINGERING HIGH PRESSURE WILL BE
IN PLACE OVER THE REGION ON SUNDAY. ANOTHER COLD FRONT WILL APPROACH
THE CWFA LATE SUN/EARLY MON AND MOVE ACROSS THE CWFA DURING THE DAY.
THE GFS CONTINUES TO BE FASTER AND A BIT DRIER OVERALL WITH THE
FROPA COMPARED TO THE ECMWF...YET BOTH MODELS ARE LOOKING PRETTY DRY
AT THIS POINT. ANOTHER HIGH WILL PUSH INTO THE REGION BEHIND THE
FRONT ON TUES AND LINGER THRU THE REMAINDER OF THE MEDIUM RANGE.
AS FOR THE SENSIBLE WX...NO SIGNIFICANT CHANGES WERE NEEDED WITH A
SLIGHT TO SOLID CHANCE POP EACH DAY AND TEMPS JUST ABOVE NORMAL FOR
LATE AUGUST.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AT KCLT...OVERALL NO CHANGE TO THINKING FOR THE KCLT TAF FOR THE 09Z
AMD. GUIDANCE SEEMS LESS PESSIMISTIC IN DEVELOPMENT OF MVFR
RESTRICTIONS THIS MORNING BUT FOR NOW WILL LEAVE TAF AS-IS GIVEN
NEARBY OBS. EXPECT IMPROVING CONDITIONS AFTER 14-15Z OR SO...WITH
ANOTHER ROUND OF TSRA POSSIBLE THIS AFTERNOON SO HAVE INTRODUCED
PROB30. WINDS GENERALLY SW THROUGH THE PERIOD BELOW 5KT...THOUGH
COULD SEE VRB GUSTY WINDS IN/NEAR TSRA.
ELSEWHERE...STILL SOME -SHRA ESPECIALLY ON FOR KAVL/KHKY/KAND
POSSIBLE ON AND OFF THE NEXT FEW HOURS. ALREADY SEEING INTERMITTENT
IFR CONDITIONS AT KAVL/KHKY AND THIS WILL CONTINUE THROUGH THE
MORNING HOURS. WILL PROBABLY SEE AT LEAST MVFR CONDITIONS...IF NOT
BRIEF IFR...AT THE UPSTATE TAFS TOWARD SUNRISE AS WELL. EXPECTED
IMPROVING CONDITIONS AFTER 14-15Z OR SO...WITH ANOTHER ROUND OF TSRA
POSSIBLE THIS AFTERNOON. KEPT PROB30 FOR KAVL/KHKY AND INTRODUCED IT
AT UPSTATE TAFS. WINDS GENERALLY SW THROUGH THE PERIOD BELOW 5KT...
THOUGH COULD SEE VRB GUSTY WINDS IN/NEAR TSRA.
OUTLOOK...A COLD FRONT WILL PUSH THROUGH THE AREA LATE THURSDAY AND
THURSDAY NIGHT. ASSOCIATED SHOWERS/THUNDERSTORMS ARE EXPECTED TO END
THURSDAY NIGHT. LINGERING LOW LEVEL MOISTURE MAY RESULT IN
RESTRICTIONS IN FOG/STRATUS EARLY FRIDAY. DRY HIGH PRESSURE BUILDING
IN FROM THE NORTH WILL LIMIT RESTRICTIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-06Z
KCLT HIGH 82% HIGH 96% HIGH 100% HIGH 100%
KGSP HIGH 87% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 72% HIGH 100% HIGH 100% HIGH 100%
KHKY MED 74% HIGH 100% HIGH 100% HIGH 100%
KGMU MED 67% HIGH 100% HIGH 100% HIGH 100%
KAND MED 72% HIGH 90% 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...JPT
NEAR TERM...TDP
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
324 AM EDT THU AUG 20 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY
BRINGING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS. IN THE
FRONTS WAKE...SOME DRYING IS EXPECTED OVER THE WEEKEND. ANOTHER WEAK
FRONT APPROACHES THE CAROLINAS ON MONDAY WITH HIGH PRESSURE MOVING
OVER THE REGION BEHIND THE FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM THURSDAY...BENIGN CONDITIONS AT AFD TIME...BUT THIS
AFTER QUITE AN EVENTFUL EVENING YESTERDAY. WARM RAIN PROCESSES AND
TRAINING CELLS RESULTED IN ANOTHER 5+ INCHES OF RAIN ACROSS PORTIONS
OF UNION COUNTY NC WHERE SOME SIGNIFICANT FLASH FLOODING WAS
REPORTED. GOOSE CREEK REMAINS HIGH WITH ONE POINT STILL IN FLOOD AT
AFD TIME.
ONTO THE FORECAST...DEEP UPPER TROUGH STRETCHING DOWN THE
MISSISSIPPI WILL BEGIN TO LIFT INTO THE GREAT LAKES AND SOUTHEAST
CANADA TODAY...WITH AN OCCLUDED COLD FRONT PUSHING TOWARD THE
SOUTHERN APPALACHIANS. THE SOUTHERN EDGE OF THE FRONT IS PROGGED TO
PUSH THROUGH THE FORECAST AREA TONIGHT BUT WASH OUT QUICKLY.
DEWPOINTS BY SUNRISE FRIDAY WILL ACTUALLY DROP INTO THE UPPER 60S
ACROSS THE UPSTATE WITH SOME UPPER 50S IN THE MOUNTAINS. WE WILL
ALSO SEE LOW TEMPERATURES A COUPLE OF DEGREES COOLER THAN WE HAVE
BEEN EXPERIENCING LATELY...BUT THE DECREASE IN DEWPOINTS WILL NOT BE
QUITE QUICK ENOUGH TO BRING LOWS DOWN TO SEASONAL NORMALS JUST YET.
ANOTHER WEAK SHORTWAVE DIVING TOWARD THE OHIO VALLEY TONIGHT...WITH
A FAIRLY POTENT VORT LOBE...WILL SERVE TO PULL UP ADDITIONAL
MOISTURE AS SURFACE PATTERN TRANSITIONS TO HIGH PRESSURE.
BIGGEST CONCERN OF THE NEAR TERM WILL BE CHANCE OF ADDITIONAL
CONVECTION TODAY. WITH THE APPROACH AND PASSAGE OF THE COLD FRONT...
CERTAINLY THERE IS ENOUGH SYNOPTIC FORCING...AND WITH PW VALUES
REMAINING GENERALLY AT OR ABOVE 2 INCHES...WE SHOULD CONTINUE TO SEE
FAIRLY EFFICIENT RAIN PRODUCERS. NOT GOOD NEWS FOR FOLKS THAT
EXPERIENCED SOME SIGNIFICANT RAINFALL AMOUNTS AND RESULTING FLASH
FLOODING LAST NIGHT. LUCKILY SBCAPE VALUES GENERALLY REMAIN BELOW
1000 J/KG SO CONVECTIVE INTENSITY SHOULD NOT BE QUITE AS BAD AS
YESTERDAY. ALL THAT SAID...HI-RES GUIDANCE NOT PARTICULARLY
IMPRESSED WITH CONVECTIVE POTENTIAL FOR THIS AFTERNOON. HRRR ONLY
HAS ISOLATED CONVECTION AT BEST EVEN THROUGH 20Z. WRF NMM AND ARW
REFLECTIVITY GUIDANCE ON PAR WITH THE HRRR. WITH THAT...KEPT POPS AT
CHANCE AT BEST ACROSS THE UPSTATE AND MOST OF THE NC PIEDMONT...WITH
LIKELIES IN THE MOUNTAINS. CONFIDENCE NOT PARTICULARLY HIGH SO WILL
HAVE TO MONITOR THROUGH THE DAY.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 310 AM EDT THURSDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
FRIDAY WITH THE UPPER TROF LIFTING NE OF THE GREAT LAKES AS HEIGHTS
BEGIN TO RISE OVER THE SE REGION. THIS PATTERN WILL PERSIST INTO THE
MEDIUM RANGE WITH VARIOUS LOBES OF SHORTWAVE ENERGY APPROACHING THE
CWFA FROM THE WEST OVER THE WEEKEND. IN ADDITION...ANOTHER COMPACT
UPPER TROF WILL DIG DOWN OVER THE US/CANADA BORDER OVER THE WEEKEND
AND MOVE ACROSS THE GREAT LAKES BY THE START OF THE MEDIUM RANGE.
ON FRIDAY...THE SFC HIGH GRADUALLY SLIDES EASTWARD AND THEN NE THRU
THE DAY AND EVENING WITH LOW LVL DRYING AS THE BNDY LAYER FLOW
BECOMES MORE NLY. THE GFS SOLUTION CONTINUES TO BE THE DRIEST MODEL
OVERALL WITH THE NAM BEING THE WETTEST. REGARDLESS OF MODEL
CHOICE...THE TREND IS FOR DRIER PROFILES AND LESS INFLUENCE FROM THE
GULF AS WE MOVE INTO SAT. ON SATURDAY...THE SFC HIGH SLIDES A BIT
FARTHER NE AND UP OVER NEW ENGLAND AS SOME WEAK WEDGING APPEARS TO
BRIEFLY DEVELOP OVER THE CAROLINAS. ANY WEDGING IS EXPECTED TO BE
SHORT LIVED WITH THE LOW LVL FLOW BECOMING WEAKER SAT AFTERNOON AND
EVENING. THE PERIOD ENDS EARLY SUN WITH THE NEXT COLD FRONT STILL
WELL TO OUR WEST AND MOSTLY LIGHT AND VRB FLOW OVER THE CWFA. AS FOR
THE SENSIBLE FCST...THE BEST CHANCES FOR ADDITIONAL PRECIP WILL BE
ON FRI WITH LOWER CHANCES FOR SAT AND SUN. MAX TEMPS WILL STRUGGLE
TO GET REACH CLIMO WHILE MIN TEMPS SHOULD START OUT ABOUT A CATEGORY
ABOVE AND COOL AROUND 2 TO 4 DEGREES THRU THE PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 255 AM EDT THURSDAY...THE MEDIUM RANGE FCST BEGINS AT 12Z ON
SUNDAY WITH FLAT UPPER RIDGING OVER THE GULF OF MEX AND ANOTHER
UPPER TROF DIGGING DOWN OVER MINNESOTA AND THE WESTERN GREAT LAKES.
OVER THE REMAINDER OF THE PERIOD...THE LONG RANGE MODELS GRADUALLY
MOVE THE TROF EASTWARD AND EVENTUALLY LIFT IT NE OF NEW ENGLAND. THE
LATEST 00Z RUN OF THE GFS REMAINS FASTER WITH THE TROFS PROGRESSION
COMPARED TO THE ECMWF...HOWEVER THEY ARE MORE SIMILAR THAN BEFORE
WITH BOTH MODELS DEVELOPING A CLOSED LOW BY EARLY NEXT WEEK. THE
UPPER RIDGING WILL REAMPLIFY OVER THE CENTRAL CONUS IN THE TROFS
WAKE BY MID TO LATE NEXT WEEK WITH THE GFS STILL QUITE A BIT MORE
ROBUST WITH THE RIDGE. AT THE SFC...LINGERING HIGH PRESSURE WILL BE
IN PLACE OVER THE REGION ON SUNDAY. ANOTHER COLD FRONT WILL APPROACH
THE CWFA LATE SUN/EARLY MON AND MOVE ACROSS THE CWFA DURING THE DAY.
THE GFS CONTINUES TO BE FASTER AND A BIT DRIER OVERALL WITH THE
FROPA COMPARED TO THE ECMWF...YET BOTH MODELS ARE LOOKING PRETTY DRY
AT THIS POINT. ANOTHER HIGH WILL PUSH INTO THE REGION BEHIND THE
FRONT ON TUES AND LINGER THRU THE REMAINDER OF THE MEDIUM RANGE.
AS FOR THE SENSIBLE WX...NO SIGNIFICANT CHANGES WERE NEEDED WITH A
SLIGHT TO SOLID CHANCE POP EACH DAY AND TEMPS JUST ABOVE NORMAL FOR
LATE AUGUST.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AT KCLT...TSRA HAS MOVED OUT FOR THE NIGHT. HOWEVER...DUE TO HIGH
MOISTURE LEVELS AND RAIN FROM YESTERDAY...EXPECT SOME MVFR VSBYS TO
DEVELOP THROUGH JUST AFTER SUNRISE...WITH MVFR CIGS POSSIBLE AS
WELL. CANNOT RULE OUT LOWER CIGS/VSBY BUT CONFIDENCE NOT
PARTICULARLY HIGH. EXPECTED IMPROVING CONDITIONS AFTER 14-15Z OR
SO...WITH ANOTHER ROUND OF TSRA POSSIBLE THIS AFTERNOON SO HAVE
INTRODUCED PROB30. WINDS GENERALLY SW THROUGH THE PERIOD BELOW
5KT...THOUGH COULD SEE VRB GUSTY WINDS IN/NEAR TSRA.
ELSEWHERE...STILL SOME -SHRA ESPECIALLY ON FOR KAVL/KHKY/KAND
POSSIBLE ON AND OFF THE NEXT FEW HOURS. ALREADY SEEING INTERMITTENT
IFR CONDITIONS AT KAVL/KHKY AND THIS WILL CONTINUE THROUGH THE
MORNING HOURS. WILL PROBABLY SEE AT LEAST MVFR CONDITIONS...IF NOT
BRIEF IFR...AT THE UPSTATE TAFS TOWARD SUNRISE AS WELL. EXPECTED
IMPROVING CONDITIONS AFTER 14-15Z OR SO...WITH ANOTHER ROUND OF TSRA
POSSIBLE THIS AFTERNOON. KEPT PROB30 FOR KAVL/KHKY AND INTRODUCED IT
AT UPSTATE TAFS. WINDS GENERALLY SW THROUGH THE PERIOD BELOW 5KT...
THOUGH COULD SEE VRB GUSTY WINDS IN/NEAR TSRA.
OUTLOOK...A COLD FRONT WILL PUSH THROUGH THE AREA LATE THURSDAY AND
THURSDAY NIGHT. ASSOCIATED SHOWERS/THUNDERSTORMS ARE EXPECTED TO END
THURSDAY NIGHT. LINGERING LOW LEVEL MOISTURE MAY RESULT IN
RESTRICTIONS IN FOG/STRATUS EARLY FRIDAY. DRY HIGH PRESSURE BUILDING
IN FROM THE NORTH WILL LIMIT RESTRICTIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-06Z
KCLT HIGH 86% HIGH 84% HIGH 100% HIGH 100%
KGSP HIGH 90% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 71% HIGH 92% HIGH 100% HIGH 100%
KHKY MED 68% HIGH 92% HIGH 100% HIGH 100%
KGMU MED 73% HIGH 92% HIGH 100% HIGH 100%
KAND MED 73% HIGH 83% 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...JPT
NEAR TERM...TDP
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
140 AM EDT THU AUG 20 2015
.SYNOPSIS...
A WEAK FRONT WILL APPROACH THE AREA ON THURSDAY...PRECEDED BY
SHOWERS AND THUNDERSTORMS. SOME DRYING IS EXPECTED OVER THE WEEKEND.
ANOTHER WEAK FRONT APPROACHES OUR AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 750 PM WED...THUNDERSHOWER ACTIVITY IS BEGINNING TO SETTLE
DOWN AS EXPECTED WITH THE ONLY HEAVY STORM IN THE AREA CONTINUING
OVER UNION COUNTY WITH CONTINUED MODERATE TO HEAVY RAINFALL FOR THE
NEXT HOUR OR TWO. ALL BUT LIGHT ACTIVITY IS EXPECTED TO END IN THE
NEXT 2 OR 3 HOURS. SOME AREAS HAVE RECEIVED VERY HEAVY RAINFALL
TODAY AND YESTERDAY WHICH IS LEADING TO SIGNIFICANT LOCALIZED
FLOODING. CHANCES FOR MORE RAIN CONTINUE TOMORROW...THOUGH THE
PROBABILITY OF PRECIP. IS NOT AS HIGH AS WAS SEEN TODAY.
AS OF 510 PM WED...UPDATED FORECAST TO CONCENTRATE PRECIPITATION TO
EASTERN PARTS OF THE CWA PER RADAR TRENDS AND HRRR GUIDANCE. RADAR
HAS HAD HEAVIEST COVERAGE OF THUNDERSTORMS MOVING EASTWARD WITH SOME
RESIDUAL ACTIVITY ELSEWHERE. HEAVIER STORMS OVER EASTERN PARTS OF
THE CWA AGREES WITH HIGHER CAPE ANALYSIS IN THAT AREA. RAINFALL
AMOUNTS WILL CONTINUE TO BE GENEROUS...GIVEN HIGH PRECIPITABLE
WATER. SHOWERS WILL BEGIN TO TAPER AFTER 3Z THIS EVENING.
AS OF 230 PM WED...RADAR CONTINUES TO SHOW INCREASING COVERAGE AND
EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE AREA THROUGH
THE AFTERNOON. SOME MORE STRATIFORM TYPE PRECIP WITH EMBEDDED
THUNDER MAY LINGER INTO THE EVENING HOURS OVER EASTERN AREAS. SPC
MESOANAL SHOWING CAPES IN THE 2000-3000J/KG RANGE OUTSIDE THE
MOUNTAINS. ALSO...THE DCAPE HIGHER TODAY THAN PREVIOUS DAYS NOW
HAVING INCREASED TO OVER 1000J EASTERN AREAS. HENCE...SEVERE STORM
CHANCES HIGHER THIS AFTERNOON AND WE SHOULD SEE SEVERAL PULSE SEVERE
STORMS. THE SEVERE THREAT WILL BE ALONG SIDE THE LOCALIZED HYDRO
THREAT.
IN REGARD TO THE BIG PICTURE...A VORT MAX IS FORECAST TO MOVE ACROSS
THE AREA DURING THE LATE AFTERNOON AND EVENING HOURS WHICH IS THE
PRIMARY TRIGGER OF THE NUMEROUS SHOWERS AND STORMS. NVA BEHIND THIS
FEATURE SHOULD RESULT IN A LULL IN PRECIP COVERAGE DURING THE
OVERNIGHT HOURS. MINIMUM TEMPS ARE EXPECTED TO BE ABOUT A CATEGORY
ABOVE CLIMO.
ON THURSDAY...A DEEP UPPER TROUGH SWINGING THROUGH THE GREAT LAKES
WILL PUSH A COLD FRONT SOUTHEASTWARD AND IT IS FORECAST TO REACH THE
MOUNTAINS DURING THE AFTERNOON. WITH DEEP LAYER MOISTURE STILL IN
PLACE...THERE STILL SHOULD BE DECENT COVERAGE OF SHOWERS AND
THUNDERSTORMS IN THE MOUNTAINS. HOWEVER EAST OF THE MOUNTAINS...WITH
FLOW BECOMING MORE ZONAL/DOWNSLOPE THE COVERAGE SHOULD BE SCT. MODEL
FORECAST SOUNDINGS ALSO INDICATE LESS CAPE...SO SEVERE THREAT
APPEARS ON THE LOW END. MAX TEMPS WILL BE NEAR TO CLIMO.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
AS OF 200 PM EDT WEDNESDAY...THE SHORT TERM FCST PERIOD INITIALIZES
THURSDAY EVENING AMIDST AN ONGOING COLD FRONTAL INTRUSION.
THE UPPER PATTERN WILL BE HIGHLIGHTED BY A DEEP NEGATIVELY TILTED
LONGWAVE TROF EJECTING THROUGH THE GREAT LAKES WHILE BROAD RIDGING
PREVAILS OVER THE DEEP SOUTH AND EASTERN GULF. AS STATED ABOVE...A
COLD FRONT WILL BE WORKING ITS WAY INTO/THROUGH THE NC HIGH TERRAIN
BY THURSDAY EVENING WITH DEEP SOUTHWESTERLY FLOW PREVAILING OUT
AHEAD. IN RESPONSE...EXPECTING ONGOING CONVECTION IN THE WARM
SECTOR AT FCST INITIALIZATION POSSIBLY AIDED BY ENHANCED SHEARING
AND VORT ADVECTION ALOFT. SHORT TERM GUIDANCE IS NOW IN BETTER
AGREEMENT WITH REGARDS TO THE TRACK/DEPTH OF THE FRONTAL PASSAGE
WITH BOTH THE GFS/NAM ALONG WITH THE ECMWF PUSHING THE BOUNDARY
SOUTH OF THE CWFA...LIKELY WASHING OUT OVER THE LOWCOUNTRY/MIDLANDS
BY MID MORNING FRIDAY.
BROAD SFC HIGH PRESSURE IS FCST TO ADVECT IN FROM THE MIDWEST
INTO THE OHIO VALLEY JUST BEHIND THE FRONT...BEFORE SLIDING OVER
THE SOUTHERN/CENTRAL APPS LATER IN THE DAY. AS A RESULT...DRIER
NORTHERLY FLOW WILL WARRANT DECREASED PRECIPITATION POTENTIAL
AND PARTLY CLOUDY SKIES ACROSS MUCH OF WESTERN NC. DUE TO CLOSER
PROXIMITY TO ANY REMNANT FRONTAL MOISTURE...LOCATIONS ALONG AND
SOUTH OF THE I85 CORRIDOR WILL SEE SLIGHTLY HIGH PROBABILITIES AND
THUS PARTLY/MOSTLY CLOUDY SKIES. NEVERTHELESS...PROFILES ARE NOT
SUPPORTIVE OF ANY DEEP CONVECTION AT THIS TIME THEREFORE NOTHING
MORE THAN GARDEN VARIETY SHOWERS WITH PERHAPS A FEW RUMBLES OF
THUNDER ARE EXPECTED. SATURDAY IS SHAPING UP TO BE THE NICEST DAY
OF THE PERIOD WITH MODELS INDICATING FURTHER DRY AIR INTRUSION
AS THE ABOVE MENTIONED SURFACE RIDGE MOVES EAST OF THE APPS.
MOSGUIDE AND TO SOME EXTENT EVEN THE RAW NAM INDICATES DEWPOINTS
IN THE UPPER 50S ACROSS NORTHWEST NC INCREASING TO THE LOWER 60S
ALONG THE I85 CORRIDOR. THUS EXPECTING MOSTLY SUNNY TO PARTLY
CLOUDY SKIES AND TEMPERATURES A FEW DEGREES BELOW NORMAL ALLOWING
FOR A BEAUTIFUL MID/LATE AUGUST DAY. THAT SAID...NAM GUID DOES
FAVORS AT LEAST SOME CHANCE FOR LOW END DESTABILIZATION OVER THE
SOUTHWEST NC MOUNTAINS AND NORTHEAST GA...THEREFORE WILL INCLUDE
POPS TO ACCOUNT FOR SUCH WITH MAX HEATING ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AT 230 PM EDT WEDNESDAY...ON SUNDAY AN UPPER RIDGE WILL BE OVER THE
WESTERN USA...WITH A MEAN TROUGH OVER THE EAST. THE PATTERN
AMPLIFIES SLIGHTLY INTO TUESDAY AS A CLOSED UPPER LOW CROSSES SOUTH
CENTRAL CANADA. THE PATTERN DEAMPLIFIES SLIGHTLY BY THURSDAY AS THE
CANADIAN LOW APPROACHES THE ATLANTIC....BY WHICH TIME SOME
PROGRESSION TAKES PLACE...AND THE UPPER TROUGH REACHES THE EASTERN
SEABOARD...WHILE THE RIDGE UPSTREAM CROSSES THE PLAINS AND EXTENDS
INTO THE GULF STATES.
AT THE SURFACE...SUNDAY STARTS OUT WITH HIGH PRESSURE ALONG THE
EASTERN SEABOARD...WITH A COLD FRONT UPSTREAM FORM THE GREAT LAKES
TO THE SOUTHERN PLAINS. THIS FRONT REACHES THE SOUTHERN APPALACHIANS
ON MONDAY...MOVING TO THE COASTAL PLAIN BY TUESDAY...WHERE IT STALLS
AND REMAINS INTO WEDNESDAY. OUR AREA CAN EXPECT AN ACTIVE PATTERN
AHEAD OF AND ALONG THE FRONT...WITH A DRYING TREND IN THE
WAKE OF THE FRONT. AT THIS TIME...PRECIPITATION AMOUNTS ARE NOT
EXPECTED TO BE EXCESSIVE AS THE FRONT DOES NOT STALL UNTIL EAST OF
OUR AREA. TEMPERATURES WILL RUN NEAR NORMAL.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...TSRA HAS MOVED OUT FOR THE NIGHT. HOWEVER...DUE TO HIGH
MOISTURE LEVELS AND RAIN FROM YESTERDAY...EXPECT SOME MVFR VSBYS TO
DEVELOP THROUGH JUST AFTER SUNRISE...WITH MVFR CIGS POSSIBLE AS
WELL. CANNOT RULE OUT LOWER CIGS/VSBY BUT CONFIDENCE NOT
PARTICULARLY HIGH. EXPECTED IMPROVING CONDITIONS AFTER 14-15Z OR
SO...WITH ANOTHER ROUND OF TSRA POSSIBLE THIS AFTERNOON SO HAVE
INTRODUCED PROB30. WINDS GENERALLY SW THROUGH THE PERIOD BELOW
5KT...THOUGH COULD SEE VRB GUSTY WINDS IN/NEAR TSRA.
ELSEWHERE...STILL SOME -SHRA ESPECIALLY ON FOR KAVL/KHKY/KAND
POSSIBLE ON AND OFF THE NEXT FEW HOURS. ALREADY SEEING INTERMITTENT
IFR CONDITIONS AT KAVL/KHKY AND THIS WILL CONTINUE THROUGH THE
MORNING HOURS. WILL PROBABLY SEE AT LEAST MVFR CONDITIONS...IF NOT
BRIEF IFR...AT THE UPSTATE TAFS TOWARD SUNRISE AS WELL. EXPECTED
IMPROVING CONDITIONS AFTER 14-15Z OR SO...WITH ANOTHER ROUND OF TSRA
POSSIBLE THIS AFTERNOON. KEPT PROB30 FOR KAVL/KHKY AND INTRODUCED IT
AT UPSTATE TAFS. WINDS GENERALLY SW THROUGH THE PERIOD BELOW 5KT...
THOUGH COULD SEE VRB GUSTY WINDS IN/NEAR TSRA.
OUTLOOK...A COLD FRONT WILL PUSH THROUGH THE AREA LATE THURSDAY AND
THURSDAY NIGHT. ASSOCIATED SHOWERS/THUNDERSTORMS ARE EXPECTED TO END
THURSDAY NIGHT. LINGERING LOW LEVEL MOISTURE MAY RESULT IN
RESTRICTIONS IN FOG/STRATUS EARLY FRIDAY. DRY HIGH PRESSURE BUILDING
IN FROM THE NORTH WILL LIMIT RESTRICTIONS THROUGH THE WEEKEND.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-00Z
KCLT HIGH 100% LOW 51% HIGH 95% HIGH 100%
KGSP HIGH 100% MED 68% HIGH 100% LOW 57%
KAVL HIGH 100% LOW 56% HIGH 100% HIGH 100%
KHKY HIGH 87% HIGH 85% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 80% HIGH 100% LOW 57%
KAND HIGH 87% LOW 46% HIGH 95% LOW 57%
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...JAT
NEAR TERM...LG/WJM
SHORT TERM...CDG
LONG TERM...JAT
AVIATION...TDP
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
956 AM EDT THU AUG 20 2015
.DISCUSSION...
A BAND OF SHOWERS ALONG THE COLD FRONT IS MAKING SLOW EASTWARD
PROGRESS...AND REFLECTIVITY TRENDS SHOW DECREASING INTESITY TO THE
RAINFALL. THE HRRR CONTINUES THIS WEAKENING TREND INTO THE
AFTERNOON. THE 12Z RNK AND FFC SOUNDINGS SHOW VERY LITTLE
INSTABILITY TO SUPPORT THUNDERSTORMS TODAY. THERE HAS BEEN SOME
HEATING WITH A LACK OF CLOUD COVER THIS MORNING NEAR THE
MOUNTAINS...SO THIS MIGHT STILL AID SOME THUNDERSTORMS THIS
AFTERNOON IN THAT AREA...BUT COVERAGE SHOULD BE LIMITED TO
ISOLATED. WILL UPDATE TO ADJUST POPS AND QPF BASED ON THESE TRENDS.
THE LATEST MODEL AND RADAR TRENDS SUGGEST THAT THE FRONT WILL BE
NEAR OUR EASTERN BORDER AROUND 00Z AND TO OUR EAST BY MIDNIGHT...SO
THE UPDATE WILL BRING POPS TO AN END MORE QUICKLY. THIS WILL
NECESSITATE SOME CHANGES TO THE FRIDAY PERIOD...REMOVING ALL POPS
FROM FRIDAY IN THE DRY AND STABLE ENVIRONMENT BEHIND THE FRONT.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1044 PM CDT FRI AUG 21 2015
.UPDATE...
Made some minor updates to decrease pops down to 20 percent
over Haskell and Throckmorton counties and extend 20-30 pops
slightly farther into Sterling and Irion counties for tonight.
Latest HRRR models indicates storms near Lamesa may move into
extreme NW portions of the Concho Valley before dissipating.
&&
.PREV DISCUSSION... /ISSUED 620 PM CDT FRI AUG 21 2015/
AVIATION...
/00Z TAFS/
Look for stratus to develop across much of West Central Texas
overnight. Models indicate MVFR ceilings are likely, mainly south
of Interstate 20, by sunrise tomorrow morning. Conditions should
return to VFR around noon tomorrow.
PREV DISCUSSION... /ISSUED 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.
&&
$$
99/04
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
934 PM CDT FRI AUG 21 2015
.UPDATE...
WE ARE DROPPING POPS THIS EVENING THROUGH 1AM...THEN LOWERING POPS
TO 20 PERCENT THROUGH 7 AM ALONG THE RED RIVER VALLEY AND OVER
THE NORTHWEST COUNTIES. HAVE ALSO TRIMMED THE SOUTHEAST COUNTIES
SOME AND EXPANDED THE RAIN-FREE AREA SIGNIFICANTLY. LATEST
TTU WRF...HRRR AND NAM12 HAVE ALL BACKED OFF ON OVERNIGHT
PRECIPITATION.
THE ONLY AREA OF ACTIVITY THAT COULD JUSTIFY HIGHER POPS IS OVER
WEST TEXAS...SOUTHWEST OF AMARILLO...BUT IT DOES NOT SHOW MUCH
SIGN OF HOLDING TOGETHER PER RADAR AND HI-RES MODELS. THE ACTIVITY
FARTHER SOUTH...NORTH OF MIDLAND...IS EXPECTED TO TRACK SOUTHEAST
THROUGH 06Z/1AM...BUT THEN WEAKEN BEFORE PASSING EAST OF SAN
ANGELO. 75
&&
.AVIATION...
/ISSUED 651 PM CDT FRI AUG 21 2015/
/00Z TAFS/
CONCERNS: LOW MVFR CIGS FROM NEAR SUNRISE TO MID-LATE MORNING AND
LOW CONVECTIVE CHANCES FOR DFW METRO AIRPORTS THAT SAME TIME FRAME.
SHORTWAVE DISTURBANCES WILL MOVE OUT OF NE NEW MEXICO AND TX/OK
PANHANDLES TONIGHT WHILE GENERATING SCATTERED CONVECTION INTO NW
TEXAS BY MID-LATE EVENING. HOW MUCH CONVECTION BLOOMS TONIGHT AND
DISSIPATES AFTER DAYBREAK IS IN QUESTION...AS THE HRRR MODEL IS
THE MOST AGGRESSIVE ON SUCH OCCURRENCE VERSUS THE TTU AND LOCAL
WRF MODELS AND NAM MODEL. WITH CONFIDENCE SHAKY REGARDING
CONVECTIVE EVOLUTION TO THE NW OVERNIGHT...WILL ONLY ADVERTISE
VCSH FROM SUNRISE TO LATE MORNING AT DFW AIRPORTS AND MONITOR
THROUGH THE EVENING FOR ANY POSSIBLE CHANGES TO ADD THUNDER AND
BETTER COVERAGE IF NEED BE.
A MOIST BOUNDARY LAYER WILL LIKELY COOL ENOUGH FOR AT LEAST BROKEN
MVFR STRATUS ACROSS ALL THE AIRPORTS FROM 10Z-12Z TO 15Z...WITH
WACO HAVING THE HIGHER CONFIDENCE OVER DFW METRO AIRPORTS. HAVE
MAINTAINED A 3-6 HOUR PD OF MVFR CIGS AT ALL NORTH TEXAS AIRPORTS
EARLY SATURDAY MORNING. 05/
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT FRI AUG 21 2015/
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE MORNING COMPLEX OF
STORMS IN SOUTHEAST TEXAS WILL CONTINUE TO WEAKEN THROUGH LATE
AFTERNOON AS THEY MOVE NORTH/NORTHEAST INTO DRIER AIR. WILL KEEP
SOME LOW POPS IN PLACE MAINLY ACROSS THE EASTERN HALF OF THE
REGION THROUGH SUNSET TO ACCOUNT FOR THIS ACTIVITY.
THE NEXT WEATHER MAKER IN THE FORM OF A FAST MOVING SHORT WAVE
TROUGH IS CURRENTLY ON THE MOVE ACROSS NEW MEXICO AND SOUTHEAST
COLORADO. THIS SYSTEM IS ALREADY PRODUCING NUMEROUS SHOWERS AND
THUNDERSTORMS. WE EXPECT THE STORMS TO FORM INTO A CONVECTIVE
COMPLEX ACROSS THE PANHANDLE AND MOVE SOUTHEAST TOWARD NORTH TEXAS
THIS EVENING/OVERNIGHT. THE COMPLEX IS PROGGED BY THE NAM...HRR
AND TEXAS TECH WRF TO REACH THE NORTHWEST ZONES AFTER MIDNIGHT.
THE STORMS SHOULD WEAKEN THROUGH THE MORNING HOURS SATURDAY AS THE
SHORT WAVE EXITS THE REGION AND LARGE SCALE SUBSIDENCE INCREASES.
SATURDAY AFTERNOON WILL BE MOSTLY SUNNY AND HOT WITH AFTERNOON
HIGHS IN THE MIDDLE AND UPPER 90S.
UPPER LEVEL HIGH PRESSURE WILL REMAIN CENTERED OVER WEST TEXAS AND
NEW MEXICO SATURDAY NIGHT THROUGH SUNDAY WHILE A STRONG UPPER
TROUGH MOVES ACROSS THE NORTHERN PLAINS. THE EASTWARD MOVEMENT OF
THE UPPER TROUGH WILL ALLOW A COLD FRONT TO SLIDE SOUTH THROUGH THE
CENTRAL PLAINS AND ACROSS THE RED RIVER ON SUNDAY. THE FRONT WILL
LOSE MUCH OF ITS PUNCH AS THE UPPER TROUGH SURGES TOWARD THE
GREAT LAKES REGION. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT WITH A SLOW SOUTHWARD MOVEMENT OF THE FRONT ACROSS
NORTH TEXAS SUNDAY THROUGH TUESDAY. WE EXPECT SHOWERS AND
THUNDERSTORMS TO ACCOMPANY THE FRONT BUT WILL KEEP COVERAGE
SCATTERED SINCE THE BOUNDARY WILL BE QUITE SHALLOW AND LARGE SCALE
FORCING WILL BE NEGLIGIBLE.
TEMPERATURES ASSOCIATED WITH THE COLD FRONT WILL ONLY BE SLIGHTLY
COOLER THAN THE PRE-FRONTAL TEMPS WITH AFTERNOON HIGHS STILL
REACHING THE 90S SUNDAY THROUGH TUESDAY.
THE COLD FRONT WILL FINALLY MOVE SOUTH OF THE FORECAST AREA
TUESDAY NIGHT AS A LONG WAVE TROUGH TAKES SHAPE ACROSS THE EASTERN
HALF OF THE NATION. DRY AIR WILL DEEPEN ACROSS THE REGION AND
THIS WILL BRING AN END TO THE PRECIPITATION CHANCES.
POST-FRONTAL HIGH TEMPERATURES WEDNESDAY THROUGH FRIDAY WILL BE
SEASONALLY WARM WITH HIGHS MAINLY IN THE MIDDLE 90S. THE DRIER
AIR WILL KEEP OVERNIGHT TEMPS A BIT COOLER OVERALL WITH LOWS
RANGING FROM THE UPPER 60S TO THE LOWER 70S. 79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 76 97 79 97 78 / 10 10 5 20 20
WACO, TX 77 96 78 98 75 / 10 10 0 10 10
PARIS, TX 71 93 74 97 73 / 10 20 5 20 30
DENTON, TX 77 95 78 95 75 / 10 10 5 20 20
MCKINNEY, TX 76 93 75 96 73 / 10 10 5 20 20
DALLAS, TX 77 95 78 98 79 / 10 10 5 20 20
TERRELL, TX 75 93 75 98 74 / 10 10 5 10 10
CORSICANA, TX 75 96 75 99 75 / 10 10 5 10 10
TEMPLE, TX 74 98 75 98 74 / 10 10 0 10 10
MINERAL WELLS, TX 74 95 74 96 73 / 10 20 5 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/75
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
651 PM CDT FRI AUG 21 2015
.AVIATION...
/00Z TAFS/
CONCERNS: LOW MVFR CIGS FROM NEAR SUNRISE TO MID-LATE MORNING AND
LOW CONVECTIVE CHANCES FOR DFW METRO AIRPORTS THAT SAME TIME FRAME.
SHORTWAVE DISTURBANCES WILL MOVE OUT OF NE NEW MEXICO AND TX/OK
PANHANDLES TONIGHT WHILE GENERATING SCATTERED CONVECTION INTO NW
TEXAS BY MID-LATE EVENING. HOW MUCH CONVECTION BLOOMS TONIGHT AND
DISSIPATES AFTER DAYBREAK IS IN QUESTION...AS THE HRRR MODEL IS
THE MOST AGGRESSIVE ON SUCH OCCURRENCE VERSUS THE TTU AND LOCAL
WRF MODELS AND NAM MODEL. WITH CONFIDENCE SHAKY REGARDING
CONVECTIVE EVOLUTION TO THE NW OVERNIGHT...WILL ONLY ADVERTISE
VCSH FROM SUNRISE TO LATE MORNING AT DFW AIRPORTS AND MONITOR
THROUGH THE EVENING FOR ANY POSSIBLE CHANGES TO ADD THUNDER AND
BETTER COVERAGE IF NEED BE.
A MOIST BOUNDARY LAYER WILL LIKELY COOL ENOUGH FOR AT LEAST BROKEN
MVFR STRATUS ACROSS ALL THE AIRPORTS FROM 10Z-12Z TO 15Z...WITH
WACO HAVING THE HIGHER CONFIDENCE OVER DFW METRO AIRPORTS. HAVE
MAINTAINED A 3-6 HOUR PD OF MVFR CIGS AT ALL NORTH TEXAS AIRPORTS
EARLY SATURDAY MORNING.
05/
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT FRI AUG 21 2015/
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE MORNING COMPLEX OF
STORMS IN SOUTHEAST TEXAS WILL CONTINUE TO WEAKEN THROUGH LATE
AFTERNOON AS THEY MOVE NORTH/NORTHEAST INTO DRIER AIR. WILL KEEP
SOME LOW POPS IN PLACE MAINLY ACROSS THE EASTERN HALF OF THE
REGION THROUGH SUNSET TO ACCOUNT FOR THIS ACTIVITY.
THE NEXT WEATHER MAKER IN THE FORM OF A FAST MOVING SHORT WAVE
TROUGH IS CURRENTLY ON THE MOVE ACROSS NEW MEXICO AND SOUTHEAST
COLORADO. THIS SYSTEM IS ALREADY PRODUCING NUMEROUS SHOWERS AND
THUNDERSTORMS. WE EXPECT THE STORMS TO FORM INTO A CONVECTIVE
COMPLEX ACROSS THE PANHANDLE AND MOVE SOUTHEAST TOWARD NORTH TEXAS
THIS EVENING/OVERNIGHT. THE COMPLEX IS PROGGED BY THE NAM...HRR
AND TEXAS TECH WRF TO REACH THE NORTHWEST ZONES AFTER MIDNIGHT.
THE STORMS SHOULD WEAKEN THROUGH THE MORNING HOURS SATURDAY AS THE
SHORT WAVE EXITS THE REGION AND LARGE SCALE SUBSIDENCE INCREASES.
SATURDAY AFTERNOON WILL BE MOSTLY SUNNY AND HOT WITH AFTERNOON
HIGHS IN THE MIDDLE AND UPPER 90S.
UPPER LEVEL HIGH PRESSURE WILL REMAIN CENTERED OVER WEST TEXAS AND
NEW MEXICO SATURDAY NIGHT THROUGH SUNDAY WHILE A STRONG UPPER
TROUGH MOVES ACROSS THE NORTHERN PLAINS. THE EASTWARD MOVEMENT OF
THE UPPER TROUGH WILL ALLOW A COLD FRONT TO SLIDE SOUTH THROUGH THE
CENTRAL PLAINS AND ACROSS THE RED RIVER ON SUNDAY. THE FRONT WILL
LOSE MUCH OF ITS PUNCH AS THE UPPER TROUGH SURGES TOWARD THE
GREAT LAKES REGION. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT WITH A SLOW SOUTHWARD MOVEMENT OF THE FRONT ACROSS
NORTH TEXAS SUNDAY THROUGH TUESDAY. WE EXPECT SHOWERS AND
THUNDERSTORMS TO ACCOMPANY THE FRONT BUT WILL KEEP COVERAGE
SCATTERED SINCE THE BOUNDARY WILL BE QUITE SHALLOW AND LARGE SCALE
FORCING WILL BE NEGLIGIBLE.
TEMPERATURES ASSOCIATED WITH THE COLD FRONT WILL ONLY BE SLIGHTLY
COOLER THAN THE PRE-FRONTAL TEMPS WITH AFTERNOON HIGHS STILL
REACHING THE 90S SUNDAY THROUGH TUESDAY.
THE COLD FRONT WILL FINALLY MOVE SOUTH OF THE FORECAST AREA
TUESDAY NIGHT AS A LONG WAVE TROUGH TAKES SHAPE ACROSS THE EASTERN
HALF OF THE NATION. DRY AIR WILL DEEPEN ACROSS THE REGION AND
THIS WILL BRING AN END TO THE PRECIPITATION CHANCES.
POST-FRONTAL HIGH TEMPERATURES WEDNESDAY THROUGH FRIDAY WILL BE
SEASONALLY WARM WITH HIGHS MAINLY IN THE MIDDLE 90S. THE DRIER
AIR WILL KEEP OVERNIGHT TEMPS A BIT COOLER OVERALL WITH LOWS
RANGING FROM THE UPPER 60S TO THE LOWER 70S.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 76 97 79 97 78 / 20 20 5 20 20
WACO, TX 77 96 78 98 75 / 20 10 0 10 10
PARIS, TX 71 93 74 97 73 / 30 20 5 20 30
DENTON, TX 77 95 78 95 75 / 30 20 5 20 20
MCKINNEY, TX 76 93 75 96 73 / 20 20 5 20 20
DALLAS, TX 77 95 78 98 79 / 20 20 5 20 20
TERRELL, TX 75 93 75 98 74 / 20 20 5 10 10
CORSICANA, TX 75 96 75 99 75 / 20 10 5 10 10
TEMPLE, TX 74 98 75 98 74 / 10 10 0 10 10
MINERAL WELLS, TX 74 95 74 96 73 / 30 20 5 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/79
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
624 PM CDT FRI AUG 21 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...A STABLE ATMOSPHERE TO PROVIDE A VFR SKY MUCH OF THE
NIGHT FOR MOST OF THE REGION. SOME MVFR CIGS TO DEVELOP OVER THE
CENTRAL REGIONS OF DEEP SOUTH TEXAS AFTER MIDNIGHT WITH KMFE
POSSIBLY BEING IMPACTED FOR A FEW HOURS. HIGH RESOLUTION MODELS
SUGGEST A MODERATE CHANCE OF MVFR A FEW HOURS EITHER SIDE OF
SUNRISE ALONG THE HIGHWAY 69C/281 CORRIDOR. THERE IS LOWER
PROBABILITY AND LOWER CONFIDENCE OF MVFR CIGS DEVELOPING EAST IN
THE VICINITY OF KHRL AND KBRO. VFR TO PREVAIL SATURDAY. LIGHT
SOUTHEAST WINDS TO INCREASE SATURDAY AFTERNOON WITH SOME GUSTS
BETWEEN 20-25KNOTS.
&&
.PREV DISCUSSION... /ISSUED 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
59...AVIATION/SHORT TERM
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
620 PM CDT FRI AUG 21 2015
.AVIATION...
/00Z TAFS/
Look for stratus to develop across much of West Central Texas
overnight. Models indicate MVFR ceilings are likely, mainly south
of Interstate 20, by sunrise tomorrow morning. Conditions should
return to VFR around noon tomorrow.
&&
.PREV DISCUSSION... /ISSUED 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.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1156 PM CDT WED AUG 19 2015
.AVIATION...
/06Z TAF/ A BROAD SWATH OF SHOWERS ALONG THE I-20 CORRIDOR WILL
PERSIST THROUGH 12Z AND SAG SOUTHWARD AS BEST LOW/MID LEVEL
FORCING GRADUALLY SHIFTS TOWARD CENTRAL TEXAS OVERNIGHT. SOME WEAK
INSTABILITY STILL EXISTS ACROSS THE REGION NORTH OF THE COLD
FRONT WHICH SWEPT THROUGH THE AREA TODAY. HOWEVER..WITH LIGHTNING
OCCURRENCE AND INTENSITY VERY LOW...WILL LEAVE MENTION OF THUNDER
OUT OF NEXT TAF ISSUANCES. A FEW SHOWERS MAY LINGER IN THE
METROPLEX AND WACO THROUGH DAYBREAK...BUT BELIEVE MOST
PRECIPITATION WILL BE SOUTH OF ALL N TEXAS AIRPORTS BY LATE THURS
MORNING. CONFIDENCE IN ADDITIONAL SIGNIFICANT SHOWER ACTIVITY WAS
NOT SUBSTANTIAL ENOUGH TO INCLUDE MENTION AFTER 10Z.
AS SHOWERS CONTINUE (OR IN THE CASE OF KACT: DEVELOP)...EXPECT
LOWER ATMOSPHERIC LAYERS TO BECOME SATURATED IN A FEW HOURS...PRODUCING
MVFR CIGS AFTER 08Z AT MOST SITES. SKIES SHOULD TRANSITION TO BKN
VFR CONDITIONS BY AROUND 15Z THURS...THEN EVENTUALLY SCATTERING
OUT AFTER NOON AS DRIER AIR BUILDS IN FROM THE NE.
NORTHEASTERLY LOW LEVEL WIND FLOW WILL GRADUALLY VEER TO AN
EASTERLY DIRECTION BY LATE THURSDAY MORNING...AVERAGING 7-10KTS AT
MOST SITES.
BRADSHAW
&&
.UPDATE...
A STRONG SURFACE COLD FRONT WILL CONTINUE MOVING THROUGH OUR
CENTRAL TEXAS COUNTIES THIS EVENING AND TOWARD THE TEXAS UPPER
COAST THROUGH THURSDAY MORNING. MEANWHILE...A SHORTWAVE TROUGH
ALOFT WILL SHIFT EASTWARD OVER THE AREA TONIGHT WITH THE 850MB
FRONT CURRENTLY TO OUR NORTHWEST MOVING THROUGH BY MORNING.
THE COMBINATION OF WEAK WAA OVER THE TOP OF THE 850MB FRONT...
RICH MOISTURE IN THE 850-700MB COLUMN ON THE 00Z FWD SOUNDING AND
FORCING FROM THE SHORTWAVE WILL RESULT IN MOSTLY LIGHT SHOWERS
ACROSS THE NORTH INTO THE PRE-DAWN HOURS WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS IN VICINITY OF THE SURFACE COLD FRONT ACROSS THE
SOUTHEAST COUNTIES OVERNIGHT AND EARLY THURSDAY MORNING. DRIER AND
COOLER AIR SHOULD CONTINUE TO FILTER IN FROM THE NORTH AND NORTHWEST
WITH PRECIPITATION CHANCES ENDING ACROSS THE IMMEDIATE RED RIVER
VALLEY SHORTLY AFTER MIDNIGHT AS THE SHORTWAVE TROUGH AXIS AND
ELEVATED FRONT ROTATE THROUGH. AREAS NORTH OF I-20 SHOULD CLEAR
OUT FIRST WITH MANY AREAS SEEING COMFORTABLY COOL MORNING LOWS
FROM THE MID 50S TO LOWER 60S...WITH MID 60S TO LOWER 70S FURTHER
SOUTH.
WILL HOLD CHANCE POPS FOR THE ENTIRE AREA OVERNIGHT WITH BEST
CHANCES ACROSS OUR SOUTHEAST COUNTIES WHERE MOISTURE...INSTABILITY
AND FORCING WILL SUSTAIN THE LONGEST. NO SEVERE WEATHER IS
EXPECTED. CLEARING OF CLOUDS AND ASSOCIATED PRECIPITATION SHOULD
CONTINUE INTO THURSDAY...AS THE SHORTWAVE TROUGH CONTINUES
PROGRESSING EAST.
05/
&&
.SYNOPSIS...
THE MAIN STORY WITH THIS FORECAST PACKAGE WILL BE THE COOLER
WEATHER AND RAIN CHANCES OVER THE NEXT 12-24 HOURS. A RETURN TO
WARM CONDITIONS IS EXPECTED LATER THIS WEEK AND THROUGH THE
WEEKEND WITH LOWER CHANCES FOR PRECIPITATION.
&&
.SHORT TERM (TONIGHT THROUGH FRIDAY)...
A VERY DIFFICULT FORECAST EXISTS WITH SOME DIFFERENCES BETWEEN
BOTH HI-RES AND COARSE MODEL SOLUTIONS. AS IS OFTEN THE
CASE...NUMERICAL WEATHER PREDICTION OFTEN STRUGGLES WITH EVENTS
THAT ARE EITHER WEAKLY FORCED OR PRIMARILY DRIVEN BY MESOSCALE
PHENOMENON. IN THE CASE OF TODAY...A BULK OF THE LARGE SCALE
FORCING FOR ASCENT WAS DISPLACED WELL TO THE NORTH OF
NORTH/CENTRAL TEXAS AND THE MAIN FOCUSING MECHANISMS FOR WHAT RAIN
DID FALL THIS MORNING AND THIS AFTERNOON WERE OUTFLOW BOUNDARIES
FROM PREVIOUS CONVECTION ACROSS OK AND THE TX PANHANDLE.
MOST OF THE CONVECTION THIS AFTERNOON ON AREA RADARS APPEAR TO BE
ALONG THE FRONT WHERE SUFFICIENT LOW LEVEL CONVERGENCE IS
OCCURRING. WITH THE FRONT STARTING TO QUICKLY MOVE SOUTHWARD MOST
OF THIS ACTIVITY IS SHORT LIVED AS IT IS BEING UNDERCUT BY THE
SHALLOWER/COOLER AIR.
FOR THE REST OF THE AFTERNOON AND TONIGHT...STILL FEEL CONFIDENT
ENOUGH THAT THERE WILL BE A COUPLE OF AREAS THAT COULD SEE SOME
MEASURABLE PRECIPITATION. THE FIRST WILL BE ALONG OUR SOUTHEAST
ZONES NEAR THE SFC-925 MB FRONT LATER THIS AFTERNOON AND INTO
TONIGHT. MOST COARSE MODELS /EXCLUDING THE NAM/ SUGGEST THAT SOME
LOW LEVEL FRONTOGENESIS WILL OCCUR AND SHOULD YIELD ISOLATED TO
SCATTERED CONVECTION. THE OVERALL SEVERE POTENTIAL SEEMS
RELATIVELY LOW...BUT GIVEN THE UNSTABLE AIRMASS AHEAD OF THE
FRONT...WOULD NOT RULE OUT A STRONG DOWNBURST OR TWO. THERE MAY BE
A SMALL HAIL RISK WITH CONVECTION NEAR THE FRONT...BUT THINK THAT
CONVECTION IS BECOMING UNDERCUT TOO QUICKLY BEFORE HAIL PRODUCTION
CAN OCCUR.
THE SECOND AREA WITH A SLIGHTLY HIGHER CHANCE FOR PRECIPITATION
WILL BE ALONG AND NORTH OF THE INTERSTATE 20 CORRIDOR WHERE 850 MB
FRONTOGENETIC FORCING IS BEING ADVERTISED. PER THE TTU WRF AND
LATEST HRRR SOME AREAS OF ISOLATED TO WIDELY SCATTERED ACTIVITY IS
EXPECTED TO DEVELOP DURING THE OVERNIGHT HOURS INTO EARLY THURSDAY
MORNING. CLOSER TO SUNRISE...THIS ACTIVITY SHOULD SHIFT SOUTHWARD
AS DRIER AIR WORKS ITS WAY IN FROM THE NORTH. CURRENTLY THINK THAT
SOME SKIES ACROSS OUR IMMEDIATE RED RIVER ZONES MAY CLEAR ENOUGH
TO ALLOW FOR SOME DECENT COOLING. WITH THE CONTINUED NORTH
WINDS...THIS SHOULD ALLOW TEMPERATURES TO FALL INTO THE 60S WITH
PERHAPS EVEN A FEW UPPER 50S ALONG THE RED RIVER.
FOR THURSDAY AND THURSDAY NIGHT...THE HIGHEST RAIN CHANCES WILL
REMAIN DOWN ALONG OUR SOUTHEASTERN ZONES WHERE THE FRONT WILL
STALL AND BEGIN TO LOSE ITS BAROCLINICITY. MAX TEMPERATURES WILL
DEPEND ON THE AMOUNT OF SUNSHINE THAT CAN FILTER IN TO HELP OFFSET
SOME OF THE COLD AIR ADVECTION. IN GENERAL THINK THAT HIGHS WILL
CLIMB INTO THE LOW TO MID 80S...EXCEPT ACROSS FAR SOUTHEASTERN
ZONES WHERE UPPER 80S MAY BE POSSIBLE...ESPECIALLY IF THE FRONT
STALLS FURTHER NORTH THAN CURRENT EXPECTATIONS. WITH THE ZONAL
FLOW ALOFT ACROSS THE CENTRAL PLAINS...LOW LEVEL FLOW SHOULD TURN
AROUND TO THE EAST AND EVENTUALLY SOUTHEAST LATE THURSDAY NIGHT
INTO FRIDAY. HELD ON TO SOME LINGERING SLIGHT CHANCE POPS ACROSS
EASTERN ZONES WITH THE MOIST EAST FLOW AS ADVERTISED BY THE ECMWF
AND GFS. INSTABILITY APPEARS MEAGER...BUT WENT AHEAD AND MENTIONED
AN ISOLATED THUNDERSTORM OR TWO IN THE WORDED FORECASTS.
FOR FRIDAY...ANOTHER UPPER WAVE LOOKS TO MOVE EASTWARD OUT FROM
THE INTERMOUNTAIN WEST. THERE IS SOME WEAK LARGE SCALE ASCENT AS
EVIDENCED BY SOME UPPER LEVEL PV ACROSS THE NORTHERN AND
NORTHEASTERN ZONES. AS A RESULT...RETAINED INHERITED SLIGHT CHANCE
POPS ON FRIDAY. WITH THE RETURN TO THE SOUTH FLOW...EXPECT AN
INCREASE IN LOW LEVEL MOISTURE AND AN INCREASE IN THE
TEMPERATURES AS WELL. TEMPERATURES WILL CLIMB BACK TOWARDS
SEASONAL NORMS ON FRIDAY...OUTSIDE ANY PRECIPITATION THAT OCCURS.
&&
.LONG TERM (SATURDAY AND SUNDAY)...
FOR SATURDAY AND SUNDAY...MAINTAINED SLIGHT CHANCES FOR
PRECIPITATION ACROSS NORTHERN AND EASTERN ZONES WITH THESE AREAS
REMAINING ON THE NORTHERN AND EASTERN FRINGES OF A BUILDING MID
LEVEL RIDGE. HIGH TEMPERATURES SHOULD CLIMB INTO THE 90S AREA
WIDE ON SATURDAY. BOTH THE GFS AND ECMWF ADVERTISE A WEAK
BACKDOOR COLD FRONT SOMETIME LATE SUNDAY. THE RIDGE SHOULD
GRADUALLY WEAKEN ON ITS EASTERN PERIPHERY WHICH MAY ALLOW FOR THE
DEVELOPMENT OF SOME PRECIPITATION ALONG THE FRONT. AS A
RESULT...HAVE INTRODUCED LOW CHANCE POPS MAINLY ALONG THE RED
RIVER AND ACROSS EASTERN ZONES FOR SUNDAY AND INTO THE DAY ON
MONDAY. THERE ARE SOME DISCREPANCIES BETWEEN THE GFS AND THE ECMWF
IN THE LONG TERM WITH REGARDS TO HOW FAR SOUTH THIS NEXT COLD
FRONT WILL SWEEP SO CONFIDENCE IS NOT HIGH ENOUGH TO DEVIATE TOO
FAR FROM A CONSENSUS/BLENDED FORECAST.
BAIN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 67 84 73 93 77 / 40 20 10 20 10
WACO, TX 69 83 74 94 76 / 30 30 20 10 5
PARIS, TX 63 79 64 89 73 / 40 20 20 30 30
DENTON, TX 63 82 69 93 76 / 40 10 10 20 20
MCKINNEY, TX 64 81 69 92 76 / 40 20 10 30 20
DALLAS, TX 68 85 74 94 78 / 40 20 10 20 10
TERRELL, TX 66 81 72 92 76 / 40 30 20 20 10
CORSICANA, TX 68 82 73 93 76 / 30 30 20 20 10
TEMPLE, TX 70 86 73 94 75 / 40 30 20 10 5
MINERAL WELLS, TX 64 83 70 94 75 / 40 20 10 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
66
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
248 PM CDT THU AUG 20 2015
.TONIGHT AND FRIDAY... FORECAST CONFIDENCE...HIGH
CLOUDS WILL SLOWLY CLEAR OUT DURING THE EVENING AND OVERNIGHT HOURS
AS A 500 MB SHORTWAVE TROUGH EVENTUALLY MAKES ITS WAY OFF TO THE
NORTH AND EAST. NAM AND RAP BUFKIT SOUNDINGS INDICATE A FAIRLY DRY
PROFILE BY 06Z TONIGHT. OVERNIGHT CLEARING...ALONG WITH CALMER
WINDS...WILL LEAD TO SOME DECENT ADIABATIC COOLING. LOWS TONIGHT
LOOK TO REACH PRIMARILY INTO THE LOWER TO MID 50S ACROSS SOUTHERN
WISCONSIN...WITH SOME ISOLATED LOCATIONS REACHING INTO THE UPPER
40S.
ONCE THE SHORTWAVE MOVES OFF TO THE EAST...A MORE ZONAL MID-LEVEL
FLOW WILL MOVE INTO THE REGION...KEEPING CONDITIONS QUIET. A PUSH OF
FEW TO SCATTERED LOW-LEVEL CLOUDS COULD APPEAR BY SUNRISE FRIDAY AS
A SURGE OF LOW-LEVEL MOISTURE MAKES ITS WAY INTO THE REGION.
ADDITIONALLY...SOME PATCHY FOG IS POSSIBLE ALONG THE WISCONSIN RIVER
VALLEY DURING THE EARLY MORNING HOURS FRIDAY. EXPECT QUIET
CONDITIONS DURING THE DAY FRIDAY AS NEGATIVE VORTICITY ADVECTION AND
SFC HIGH PRESSURE WILL BE IN CONTROL OVER THE REGION. SSW WINDS WILL
BECOME GUSTY AGAIN DURING THE DAY FRIDAY...ALTHOUGH NOT AS STRONG AS
WINDS FROM THURSDAY.
.FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE IS HIGH.
HIGH PRESSURE WILL REMAIN ANCHORED OVER THE EASTERN GREAT
LAKES...KEEPING US DRY THROUGH SATURDAY. WE SHOULD SEE SOME
RADIATIVE COOLING FRIDAY NIGHT...BUT IT WILL BE TEMPERED BY SOME
DECENT WINDS AND MIXING JUST ABOVE THE BOUNDARY LAYER. A TROUGH OF
LOW PRESSURE AND IS ASSOCIATED COLD FRONT WILL APPROACH THE REGION
ON SATURDAY...TIGHTENING UP THE PRESSURE GRADIENT ACROSS THE
FORECAST AREA. LOOK FOR SOUTHERLY WINDS TO INCREASE AND BECOME
QUITE GUSTY IN THE AFTERNOON. TEMPS SHOULD CLIMB INTO THE LOWER
AND MID 80S.
.SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
THE TROUGH/CDFNT TO THE WEST WILL PUSH INTO SOUTHERN WISCONSIN
AFTER MIDNIGHT SATURDAY NIGHT. THE MODELS SHOW BETTER SUPPORT
THROUGH A DEEP LAYER UPSTREAM...BUT IT WEAKENS AS THE SFC TROUGH
MOVES IN. GIVEN THE LATE TIMING OF THE TROUGH ARRIVAL AND THE
WEAKENING SUPPORT...I/LL BE SOMEWHAT CONSERVATIVE IN PRECIP
CHANCES AS IT TRACKS EAST THROUGH SUNDAY MORNING. THE BEST CHANCE
FOR RAIN WILL BE WEST AND NORTH OF MADISON LATE SATURDAY NIGHT
INTO SUNDAY MORNING. WEAKER CHANCES ALONG THE WI/IL BORDER AND THE
SOUTHEAST.
THE TROUGH AND CDFNT WILL EXIT EASTERN WISCONSIN DURING THE EARLY
AFTERNOON WITH COOLER AND DRIER AIR MOVING RIGHT BACK IN.
.MONDAY THROUGH THURSDAY...FORECAST CONFIDENCE IS HIGH.
BIG CANADIAN HIGH PRESSURE BUILDS IN FOR MUCH OF NEXT WEEK. EXPECT
DRY CONDITIONS WITH HIGHS IN THE 70S AND LOWS IN THE 50S. WE MIGHT
SEE ANOTHER TROUGH APPROACH LATE IN THE WEEK FOR A CHANCE OF RAIN.
LOTS OF MODEL UNCERTAINTY WITH THAT.
&&
.AVIATION/00Z TAFS/...
EXPECT VFR CIGS AND VSBYS TONIGHT AS AN AREA OF LOW PRESSURE SLOWLY
MAKES ITS WAY OFF TO THE NORTH AND EAST. THE LAST OF THE LOW- TO MID-
LEVEL CLOUDS WILL SLOWLY MOVE OUT BY THE EARLY EVENING. WINDS WILL
WEAKEN THIS EVENING AS SFC PRESSURE GRADIENT WEAKENS AND THE
BOUNDARY LAYER DECOUPLES. WINDS WILL BECOME MORE NORTHWESTERLY THIS
EVENING AS THE AREA OF LOW PRESSURE MOVES OFF TO THE EAST. THERE
COULD BE SOME PATCHY FOG DEVELOPING JUST WEST OF THE MSN TAF SITE IN
THE WISCONSIN RIVER VALLEY...BUT NOT FORECAST TO AFFECT THE MSN AREA
DIRECTLY. GUSTY WINDS WILL RETURN FROM THE SOUTH-SOUTHWEST DURING
THE DAY FRIDAY.
&&
.MARINE...
SMALL CRAFT ADVISORY FOR ALL NEARSHORE ZONES WILL CONTINUE UNTIL 00Z
TONIGHT AS WINDS WILL WEAKEN BY THAT TIME DUE TO WEAKENING SFC
PRESSURE GRADIENT. WINDS WILL EVENTUALLY VEER FROM THE WEST THIS
EVENING TO A MORE NORTHWESTERLY DIRECTION. NEARSHORE WINDS WILL
ABATE TONIGHT...BUT EXPECT GUSTY SSW WINDS TO RETURN DURING THE
DAY FRIDAY...ALTHOUGH NOT EXPECTED TO REACH SMALL CRAFT ADVISORY
CRITERIA.
&&
.BEACHES...
BREEZY WESTERLY WINDS WILL PERSIST UNTIL EARLY EVENING. WIND SPEEDS
WILL MOSTLY BE BETWEEN 15 TO 25 MPH. SWIM RISK WILL BE LOW DUE TO
MORE OF AN OFFSHORE WIND EXPECTED. GUSTY SOUTH-SOUTHWEST WINDS ARE
EXPECTED TO RETURN DURING THE DAY FRIDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/FRIDAY AND AVIATION/MARINE...JTS
FRIDAY NIGHT THROUGH THURSDAY...DAVIS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1020 AM CDT THU AUG 20 2015
.UPDATE...
LINGERING SCATTERED SHOWERS WILL CONTINUE INTO THE LATE MORNING
HOURS AS 500 MB SHORTWAVE TROUGH AND ASSOCIATED SFC LOW PRESSURE
IS SITUATED TO OUR NORTH. HOWEVER...SHORTWAVE WILL MOVE OFF TO THE
NORTH AND EAST...DIMINISHING SHOWER ACTIVITY BY THE AFTERNOON AND
SLOWLY CLEARING OUT SKIES BY THE LATE AFTERNOON AND EVENING.
WESTERLY WINDS WILL REMAIN GUSTY THIS AFTERNOON WITH GOOD
BOUNDARY LAYER MOMENTUM TRANSPORT ACCORDING TO RAP AND NAM BUFKIT
SOUNDINGS. WINDS WILL SLOWLY SHIFT TO A MORE NORTHWESTERLY
DIRECTION THIS AFTERNOON AND EVENING AS LOW PRESSURE SHIFTS TO THE
EAST.
&&
.AVIATION/18Z TAFS/...
VCSH WILL COME TO AN END LATE THIS MORNING AND AFTERNOON AS AN
AREA OF LOW PRESSURE TO OUR NORTH WILL SLOWLY MOVE ITS WAY TO THE
NORTH AND EAST. AS LOW PRESSURE MOVES AWAY...SKIES WILL SLOWLY
CLEAR OUT AND CIG HEIGHTS WILL IMPROVE BY AFTERNOON. WESTERLY WINDS
WILL STAY GUSTY THIS AFTERNOON AS BUFKIT RAP AND NAM SOUNDINGS
INDICATE GOOD MOMENTUM TRANSPORT IN THE BOUNDARY LAYER...BUT WILL
WEAKEN BY THE EVENING HOURS AS SFC PRESSURE GRADIENT WEAKENS AND
BOUNDARY LAYER DECOUPLES. WINDS ARE EXPECTED TO VEER SLIGHTLY
FROM THE NORTHWEST THIS AFTERNOON AND EVENING.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT THU AUG 20 2015/
TODAY AND TONIGHT... FORECAST CONFIDENCE - HIGH.
MID-LEVEL SHORT WAVE ROTATING AROUND UPPER LOW PRODUCING SCATTERED
-SHRA AND SPRINKLES...MAINLY OVER NRN AND PARTS OF EASTERN CWA
OVERNIGHT. -SHRA WL CONTINUE TO DIMINISH THROUGH 12Z BUT SOME
LINGERING SPRINKLES ARE POSSIBLE AS LOW PRESSURE TROF LINGERS OVER
AREA THRU MID-MRNG. THERMAL TROF AND WEAK COLD AIR ADVECTION WL
CONTINUE TO BRING STRATUS TO MOST OF THE AREA THRU THE MORNING.
HOWEVER UPPER LOW WL BE WEAKENING AND SHIFTING NORTHEAST THRU THE
DAY IN RESPONSE TO UPSTREAM WEAK KICKER SYSTEM CROSSING SRN
CANADA. WITH THERMAL TROF SHIFTING EAST AND THINNING COLUMN
MOISTURE... EXPECT DECREASING CLOUDS FROM WEST TO EAST FROM LATE
MRNG THRU THE EARLY EVE.
ANOTHER BREEZY DAY IS EXPECTED DUE TO LINGERING PRESSURE GRADIENT
BUT WINDS WILL DROP OFF RAPIDLY WITH LOSS OF INSOLATION EARLY THIS
EVENING. MOSTLY CLEAR SKIES AND LIGHTER SFC WINDS WILL ALLOW TEMPS
TO FALL INTO THE UPPER 40S TO LOWER 50S MOST AREAS...WHICH WILL BE
THE COOLEST NIGHT SINCE EARLY JULY. LIGHTER BOUNDARY LAYER WINDS
ACROSS THE WESTERN CWA SHOULD ALLOW VALLEY FOG TO DEVELOP AFTER
MIDNIGHT. MID-LEVEL CLOUDS WILL INCREASE ACROSS FAR WESTERN CWA
LATE TONIGHT DUE TO UPSTREAM MID-LEVEL WARM AIR ADVECTION SURGE.
FRIDAY AND SATURDAY...FORECAST CONFIDENCE...HIGH
HIGH PRESSURE CENTERED TO THE EAST OF WISCONSIN WILL BRING VERY
PLEASANT WEATHER TO THE FORECAST AREA FRIDAY AND SATURDAY. MID
LEVEL WARM ADVECTION MAY BRING SOME CLOUDS FOR FRIDAY
MORNING...DIMINISHING IN THE AFTERNOON. LOOKS LIKE PLENTY OF
SUNSHINE THEN SATURDAY. HIGHS BOTH DAYS WILL BE WITHIN A COUPLE
DEGREES OF NORMAL IN THE UPPER 70S AND LOW 80S. SOUTHERLY WINDS
WILL BE A BIT BREEZY ON THE WESTERN EDGE OF THE HIGH.
SATURDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
A COLD FRONT IS EXPECTED TO BRING A CHANCE FOR SHOWERS AND STORMS
TO THE FORECAST AREA SATURDAY NIGHT INTO SUNDAY. MODELS ARE IN
PRETTY GOOD AGREEMENT THAT THE BEST CHANCE WILL BE BETWEEN
MIDNIGHT SATURDAY NIGHT AND NOON SUNDAY.
DRY WEATHER IS THEN EXPECTED THROUGH WEDNESDAY UNDER HIGH
PRESSURE.
SHOULD SEE HIGH TEMPS A COUPLE TO FEW DEGREES BELOW NORMAL VALUES
FOR THE FIRST HALF OF NEXT WEEK.
AVIATION/12Z TAFS/...
STILL EXPECT MOSTLY MVFR CIGS THIS MRNG AS LOW PRESSURE OVER LAKE
SUPERIOR PUSHES NORTHWARD INTO SRN CANADA. LATEST SFC OBS AND 11-
3.9 MICRON IMAGERY SHOWING SOME THIN SPOTS AND HOLES IN THE STRATUS
FIELD BRUSHING FAR SRN WI. HIGHER CIGS MAY BRIEFLY AFFECT TAF SITES
FOR AN HOUR OR TWO EARLY THIS MRNG. ALSO...SCATTERED -SHRA AND
SPRINKLES WILL DIMINISH THIS MRNG. DEEPER MOISTURE AND THERMAL TROF
SHIFT EWD TODAY SO STILL EXPECT DECREASE IN CLOUD COVER AND RAISING
CIGS THIS AFTN AND EARLY EVE.
MARINE...
EXPECT ANOTHER DAY OF GUSTY SOUTHWEST WINDS VEERING TO THE WEST THIS
MORNING AS LOW PRESSURE MOVES FROM NEAR LAKE SUPERIOR ACROSS
SOUTHERN CANADA TOWARD HUDSON BAY. SEVERAL TUGS MOVING NORTH IN THE
NEARSHORE WATERS OF LAKE MICHIGAN HAVE REPORTED SUSTAINED WINDS OF
18 TO 20 KNOTS OVER THE LAST SEVERAL HOURS. FREQUENT GUSTS TO
AROUND 25 KTS ARE EXPECTED TO REDEVELOP LATER THIS MORNING
CONTINUING THRU THE AFTN. HENCE THE SMALL CRAFT ADVISORY WILL
REMAIN IN EFFECT THRU 00Z. THE GUSTY WEST WINDS WILL DIMINISH
RAPIDLY EARLY THIS EVE.
BEACHES...
ANOTHER BREEZY DAY LIES AHEAD FOR BEACHES ALONG LAKE MICHIGAN. THE
SWIM RISK HOWEVER WILL BE LOW DUE TO MORE OF AN OFFSHORE WEST WIND
EXPECTED...RESULTING IN WAVE HEIGHTS OF 1 TO 3 FEET. MORNING CLOUDS
WILL GRADUALLY CLEAR IN THE AFTN/EARLY EVE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...JTS
TODAY/TONIGHT AND AVIATION/MARINE...MBK
FRIDAY THROUGH WEDNESDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
603 AM CDT THU AUG 20 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT THU AUG 20 2015
MAIN FORECAST CONCERNS ARE ON LINGERING LIGHT RAIN SHOWERS THIS
MORNING AND CLOUD TRENDS THROUGH THE DAY AS LOW PRESSURE EXITS.
LATEST WATER VAPOR IMAGERY EARLY THIS MORNING SHOWED UPPER LEVEL LOW
PRESSURE OVER SOUTHWEST ONTARIO LIFTING NORTHEAST. A TRAILING
TROUGH ACROSS THE UPPER MISSISSIPPI RIVER VALLEY WILL GRADUALLY
PROGRESS NORTHEAST TODAY. ISOLATED SHOWERS AND PATCHY DRIZZLE WILL
CONTINUE THIS MORNING MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER
ACROSS WESTERN INTO CENTRAL WISCONSIN . WE SHOULD SEE THIS
ACTIVITY TAPER OFF BY MID MORNING AND EXIT TO THE NORTHEAST BY
EARLY THIS AFTERNOON. LATEST IR IMAGERY AND SURFACE OBSERVATIONS
SHOW CLOUDS WERE CLEARING WEST OF THE INTERSTATE 35 CORRIDOR IN
SOUTHERN MINNESOTA/NORTHERN IOWA. HOWEVER..TAKING A LOOK UPSTREAM
TO THE NORTHWEST A FAIRLY EXPANSIVE CLOUD DECK REMAINED AND IS
EXPECTED TO MOVE SOUTHEAST AS MOISTURE CONTINUES TO WRAP AROUND
THE TROUGH. THIS WILL CREATE A CHALLENGING CLOUD FORECAST FOR
TODAY. FORECAST GUIDANCE IS TRYING TO PUSH THE CLOUDS EAST FAIRLY
QUICKLY THIS MORNING INTO THIS AFTERNOON AND IN FACT SEEMS A
LITTLE TOO FAST GIVEN OBSERVATIONS THIS MORNING. HAVE SLOWED THE
CLEARING TREND IN CLOUD COVER TODAY WITH CLEARING EXPECTED TO
APPROACH THE MISSISSIPPI RIVER FROM THE WEST BY EARLY THIS
AFTERNOON. WE SHOULD THEN SEE A GRADUAL DECREASE IN CLOUD COVER
ACROSS WESTERN INTO CENTRAL WISCONSIN THROUGH THE AFTERNOON INTO
THE EARLY EVENING HOURS. PLAN ON HIGHS TODAY RANGING FROM AROUND
60 ACROSS NORTHERN WISCONSIN TO THE UPPER 60S TO LOWER 70S ACROSS
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA. A WEAK RIDGE THEN BUILDS
IN TONIGHT WITH QUIET WEATHER EXPECTED. A WEAK SHORTWAVE MOVES
THROUGH OVERNIGHT BRINGING SOME SCATTERED TO BROKEN CLOUD COVER TO
THE AREA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 316 AM CDT THU AUG 20 2015
MAIN FORECAST CONCERNS ARE ON GUSTY SOUTHERLY WINDS ON SATURDAY THEN
FOCUS TURNS TO THUNDERSTORM CHANCES LATE SATURDAY AFTERNOON
THROUGH SATURDAY NIGHT.
SOUTHERLY FLOW INCREASES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY
ON FRIDAY AS THE PRESSURE GRADIENT TIGHTENS BETWEEN HIGH PRESSURE
CENTERER OVER THE EASTERN GREAT LAKES/NEW ENGLAND AND LOW PRESSURE
DEVELOPING OVER THE NORTHERN PLAINS. IT WILL BE BREEZY ON FRIDAY
WITH SOUTH WINDS OF 11 TO 17 MPH WITH GUSTS APPROACHING 28 MPH
DURING THE AFTERNOON HOURS. LOOK FOR HIGHS TO REBOUND INTO THE MID
70S TO AROUND 80. THE PRESSURE GRADIENT WILL CONTINUE TO STRENGTHEN
ON SATURDAY AS A COLD FRONT AND TROUGH APPROACH FROM THE WEST. IT
WILL BE A WINDY DAY ACROSS THE REGION WITH SOUTH WINDS OF 15 TO 25
MPH WITH GUSTS APPROACHING 35 MPH IN OPEN AREAS. WE SHOULD SEE
INCREASING MOISTURE AHEAD OF THE COLD FRONT ALLOWING 0-1 MUCAPE
VALUES TO CLIMB INTO THE 1000 TO 2000 J/KG RANGE WEST OF THE
MISSISSIPPI RIVER. THUNDERSTORMS LOOK TO INITIATE SATURDAY
AFTERNOON NEAR THE INTERSTATE 35 CORRIDOR THEN PUSH EAST INTO
EASTERN MINNESOTA/IOWA. THE CAPE THEN REALLY STARTS TO WANE AS THE
STORMS PROGRESS EAST DURING THE LATE MORNING INTO THE OVERNIGHT
HOURS. ITS INTERESTING TO NOTE THAT STRONGER SHEAR ATTEMPTS TO
CATCH UP TO THE CAPE AXIS SATURDAY EVENING WHICH COULD CREATE A
WINDOW OF OPPORTUNITY FOR A FEW STRONG TO PERHAPS SEVERE STORMS
WEST OF THE MISSISSIPPI RIVER. 0-3 KM BULK SHEAR VALUES INCREASE
TO 30 TO 35 KTS ACROSS THESE AREAS. IF THIS OCCURS...THE MAIN
HAZARD FROM ANY STRONG TO POSSIBLY SEVERE STORMS WOULD BE SOME
DAMAGING WIND GUSTS. THE FRONT WILL SWEEP THOUGH THE FORECAST AREA
THEN SATURDAY NIGHT...EXITING BY EARLY SATURDAY MORNING. THE UPPER
TROUGH THEN SWINGS THROUGH ON SUNDAY AND MAY PRODUCE SCATTERED
SHOWERS ACROSS WESTERN INTO CENTRAL WISCONSIN. HIGH PRESSURE THEN
BUILDS INTO THE REGION MONDAY INTO WEDNESDAY WITH DRY AND QUIET
WEATHER EXPECTED. WILL HAVE TO KEEP AN EYE ON VALLEY FOG POTENTIAL
WEDNESDAY AND POSSIBLY THURSDAY MORNINGS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 603 AM CDT THU AUG 20 2015
SATELLITE IMAGERY THIS MORNING SHOWS THE BACK EDGE OF THE CLOUDS
MAY BE ADVANCING TO THE NORTHEAST A LITTLE QUICKER THAN EXPECTED.
THE 20.09Z RAP SEEMS TO HAVE A DECENT HANDLE ON THIS AND INDICATES
KRST SHOULD SCATTERED OUT BY MID MORNING. KLSE COULD SCATTER OUT
LATE THIS MORNING...BUT SOMEWHAT CONCERNED THAT THE WESTERN EDGE
OF THE CLOUDS COULD SLOW DOWN OR EXPAND AS THE HEATING CREATES
SOME OMEGA THROUGH THE MOISTURE FIELD. BASED ON THIS...WILL HOLD
THE CLOUDS IN UNTIL EARLY AFTERNOON AT KLSE BUT BY THIS TIME
EXPECT THEM TO BE VFR. THE NORTHWEST WINDS WILL BE A BIT GUSTY
UNTIL THE GRADIENT RELAXES LATE THIS AFTERNOON. HIGH PRESSURE
BUILDS IN TONIGHT FOR CLEAR SKIES. NOT EXPECTING ANY VALLEY FOG AS
THE 20.06Z NAM CONTINUES TO SHOW WINDS OF 15 TO 20 KNOTS AT THE
TOP OF THE LOW LEVEL INVERSION AND ALSO DOES NOT SATURATE BELOW
THE INVERSION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1108 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 MINIMUMS 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 AFTERNOON/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 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1036 PM MDT FRI AUG 21 2015
DRY NORTHWEST FLOW WITH VFR EXPECTED ACROSS FLIGHT AREA THROUGH
18Z SATURDAY. AFTER 18Z...ISOLATED THUNDERSTORMS WILL BEGIN TO
DEVELOP OVER THE MOUNTAINS. FROM 21Z TO 03Z...A COLD FRONT WILL
PUSH SOUTH FROM THE PALMER DIVIDE INTO NEW MEXICO TRIGGERING A FEW
SHOWERS AND THUNDERSTORMS. AFTER 03Z...THE FRONT WILL PUSH WEST
THROUGH THE EASTERN MOUNTAINS INTO THE WESTERN MOUNTAINS AND HIGH
VALLEYS...CONTINUING TO TRIGGER A FEW SHOWERS OR THUNDERSTORMS.
GENERALLY VFR EXPECTED TO CONTINUE ACROSS THE FLIGHT AREA BEHIND
FRONTAL PASSAGE SATURDAY AFTERNOON AND EVENING. HOWEVER...LOCAL
MVFR/IFR CONDITIONS WILL BE POSSIBLE IN SHOWERS AND THUNDERSTORMS.
ADDITIONALLY...THERE COULD BE SOME AREAS OF MVFR/IFR STRATUS
BEHIND THE FRONT...ESPECIALLY IN AND NEAR THE MOUNTAINS LATE
SATURDAY AND SATURDAY EVENING.
FOR KCOS...GENERALLY VFR UNTIL 21Z...THEN POSSIBLE THUNDERSTORMS
DEVELOPING WITH LOCAL MVFR/IFR FOLLOWING FRONTAL PASSAGE. FOR
KPUB...GENERALLY VFR UNTIL 23Z...THEN POSSIBLE THUNDERSTORMS
DEVELOPING FOLLOWING FRONTAL PASSAGE. FOR KALS...POSSIBLE VCTS
BEGINNING AFTER 21Z...WITH FRONTAL PASSAGE THERE 03Z-06Z SATURDAY
EVENING.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...LW
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
135 AM EDT SAT AUG 22 2015
.UPDATE...
/ISSUED AT 1045 PM EDT FRI AUG 21 2015/
SHOWERS HAVE DISSIPATED FOR NOW. WITH THE MOIST AIR MASS AND
LINGERING MARGINAL INSTABILITY...HAVE EXTENDED A SLIGHT CHANCE OF
SHOWERS AND A FEW THUNDERSTORMS THROUGH THE NIGHT. OTHERWISE NO
CHANGES.
41
PREVIOUS...
.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...
06Z UPDATE...
PATCHY FOG AND PATCHES OF LOW IFR/MVFR STRATUS IS EXPECTED TO
DEVELOP EARLY THIS MORNING BY 09Z...BUT THINKING THE GREATEST THREAT
OF THIS WILL BE SOUTH OF ATL. EXPECT SOME BKN MID LEVEL CIGS BY 14-
15Z WITH INITIAL DAYTIME HEATING. THESE CIGS THEN SCT BY 18Z SAT.
MODELS SHOW AN UPPER DISTURBANCE APPROACHING THE STATE LATE SAT...
WARRANTING A PROB30 -TSRA 21Z SAT THRU 01Z SUN. LIGHT NNE WINDS THIS
MORNING WILL BACK MORE NNW BY 15-17Z SAT... AND HOLD NNW THRU SAT
EVENING. WINDS VEER MORE NNE BY 05-06Z SUN. SPEEDS 7KTS OR LESS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM TO HIGH ON ALL ELEMENTS.
39
&&
.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...41/39
LONG TERM....BDL
AVIATION...39
AREA FORECAST DISCUSSION
NWS LINCOLN IL
330 AM CDT SAT AUG 22 2015
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
MOST OF OUR AREA STILL UNDER THE INFLUENCE OF HIGH PRESSURE WHICH
HAS SHIFTED INTO SOUTHEAST OHIO EARLY THIS MORNING. MEANWHILE TO
OUR SOUTHWEST...A WEAK SHORTWAVE WAS TRACKING EAST ACROSS WESTERN
MISSOURI WITH SHORT TERM MODELS CONTINUING TO SUGGEST SHOWERS AND
STORMS WILL EXPAND IN COVERAGE EARLY THIS MORNING AS THE UPPER LEVEL
WAVE TRACKS EAST. HOWEVER...BOTH THE RAP-13 AND HRRR MODELS HAVE
OVERDONE THE PRECIP ACROSS SOUTHWEST MISSOURI EARLY THIS
MORNING...ESPECIALLY COMPARED TO WHAT IS ACTUALLY OCCURRING NOW.
FORECAST SOUNDINGS INDICATE A BIT MORE CLOUD COVER OVER OUR WEST AND
SOUTHWEST COUNTIES AHEAD OF THE AFOREMENTIONED WAVE TODAY WITH SOME
850 MB MOISTURE CONVERGENCE SEEN ON THE MODELS THIS MORNING OVER
PARTS OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...ESPECIALLY LATE
THIS MORNING...TOWARDS 18Z. HAVE ADDED SOME SLIGHT CHANCE POPS OVER
FAR WEST AND SOUTHWEST IL FOR THIS MORNING INTO EARLY THIS AFTERNOON
JUST AHEAD OF THE WEAKENING UPPER WAVE. FURTHER EAST AND NORTH...
LESS CLOUD COVER SHOULD ALLOW AFTERNOON TEMPS TO RISE INTO THE LOW
TO MID 80S BASED OFF THE RAP SOUNDINGS.
&&
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
RAIN CHANCES INCREASING OVERNIGHT AND INTO TOMORROW AS A COLD FRONT
APPROACHES THE FORECAST AREA. PASSAGE OF THE COLD FRONT EXPECTED IN
THE EARLY MORNING HOURS THROUGH MIDDAY. WITH A LACK OF DIURNAL
HEATING IN THE AIRMASS OUT AHEAD OF THE BOUNDARY, HAVE PULLED THE
MAX TEMPS DOWN A COUPLE DEGREES. SOUTHEAST MAY REMAIN SOMEWHAT
WARMER FOR SUNDAYS HIGHS AND ILX WILL LIKELY HAVE QUITE A GRADIENT
OVER THE REGION. WITH THE GENERAL EARLINESS OF THE SYSTEM, LITTLE TO
NO SEVERE WEATHER IS EXPECTED. BEHIND THE COLD FRONT, HIGH PRESSURE
BUILDS BACK IN AT THE SURFACE. IN THE COOLER AIRMASS, THE TEMPS WILL
REMAIN SLIGHTLY BELOW NORMAL THROUGH MIDWEEK...BUT TRENDING WARMER.
THE WARM TREND WILL BE ENHANCED EVEN FURTHER AS THE HIGH PRESSURE
RIDGE AXIS SLIPS OFF TO THE EAST AND THE SFC WINDS BECOME MORE
SOUTHERLY AHEAD OF THE NEXT FRONT. AT THIS POINT, SOLUTIONS ARE NOT
CONSISTENT IN THE MODELS AND THE SUPERBLEND IS AN AMALGAM OF BOTH
THE WETTER SOLUTION AND THE MORE SPARSE WITH THE QPF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1149 PM CDT FRI AUG 21 2015
VFR AVIATION WEATHER CONDITIONS EXPECTED THROUGH THE 06Z TAF
VALID TIME, BUT AFTERNOON AND EVENING CLOUDS WILL BECOME MORE
PROMINENT AS MID AND UPPER LEVEL MOISTURE INCREASES AHEAD OF AN
APPROACHING COLD FRONT. CLEAR SKIES ARE EXPECTED TONIGHT AND
TOMORROW MORNING, ALTHOUGH SOME LIGHT MVFR FOG COULD DEVELOP IN
EASTERN IL LATE TONIGHT NEAR CMI, PER THE LATEST HRRR OUTPUT.
LOOK FOR WINDS TO BE S-SW AT 5-7KT THE REST OF THE NIGHT, THEN
INCREASE FROM THE SE SATURDAY MORNING, WITH GUSTS TO 16-18KT FOR
THE NW TERMINALS OF PIA/BMI.
EVEN THOUGH THE NEXT COLD FRONT IS SLATED TO ARRIVE LATE SATURDAY
NIGHT INTO SUNDAY MORNING, FORECAST SOUNDINGS ARE POINTING TOWARD
AN OVERCAST SKY /5K FT/ BEFORE 06Z AT PIA AND BMI, AND POSSIBLY
10K FT CEILING ELSEWHERE. RAIN SHOULD HOLD OFF UNTIL AFTER 06Z,
BUT CAN`T RULE OUT SPRINKLES LATE IN THIS TAF PERIOD.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1149 PM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 908 PM CDT FRI AUG 21 2015
HIGH SURFACE PRESSURE WILL CONTINUE TO DRIFT EAST OF ILLINOIS
OVERNIGHT, BUT WILL STILL MAINTAIN CONTROL OF THE WEATHER OVER THE
NEXT 24 HOURS. SOUTH TO SOUTHEAST WINDS AT 5-8 MPH ARE EXPECTED
TONIGHT. THE STEADY WINDS SHOULD HELP TO KEEP FOG AT BAY, DESPITE
CLEAR SKIES AND LOW TEMPS EXPECTED TO DROP INTO THE MID TO UPPER
50S (NEAR THE AFTERNOON DEWPOINT TEMPS).
THE FORECAST GRIDS LOOK IN GOOD SHAPE, AND NO CHANGES WERE NEEDED
FOR TONIGHT AND TOMORROW.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 253 PM CDT FRI AUG 21 2015
FAIR WEATHER EXPECTED TONIGHT THANKS TO 1021 MB HIGH PRESSURE OVER
IN/KY/OH BORDER THAT MOVES INTO THE EASTERN GREAT LAKES BY MIDDAY
SAT. SCATTERED CUMULUS CLOUDS OVER CENTRAL AND SOUTHEAST IL THIS
AFTERNOON TO DISSIPATE AT SUNSET LEAVING FAIR SKIES. SOUTH WINDS 5
TO 15 MPH TO ALSO DIMINISH LIGHT AFTER SUNSET. LOWS OVERNIGHT OF 55-
60F WITH COOLEST READINGS IN EASTERN IL CLOSER TO HIGH PRESSURE
RIDGE AND WHERE WINDS WILL BE LIGHTEST. A WEAK SHORT WAVE EJECTS OUT
OF CENTRAL PLAINS INTO MO OVERNIGHT KEEPING ISOLATED SHOWERS AND
THUNDERSTORMS SW OF IL. SOME VERY PATCHY SHALLOW GROUND FOG COULD
DEVELOP LATE TONIGHT NEAR RIVERS/STREAMS IN SOUTHEAST IL BUT
COVERAGE TOO LIMITED TO MENTION IN FORECAST.
.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 253 PM CDT FRI AUG 21 2015
AN EXTENDED PERIOD OF REMARKABLY QUIET AND PLEASANT LATE AUGUST
WEATHER IS ON TAP ACROSS CENTRAL AND SOUTHEAST ILLINOIS. THERE IS
ONLY ONE SIGNIFICANT THREAT OF RAINFALL OVER THE NEXT SEVERAL DAYS,
AND THIS IS ASSOCIATED WITH THE PASSAGE OF A COLD FRONT ON SUNDAY.
MODEL AGREEMENT HAS TIGHTENED UP WITH THE FRONTAL TIMING, HAVING IT
SWEEP FROM WEST TO EAST ACROSS THE FORECAST AREA DURING THE DAYTIME
HOURS ON SUNDAY. THE TIMING OF THE FRONT IS NOT CONDUCIVE TO
SIGNIFICANT SHOWER/STORM COVERAGE OR INTENSITY. THE BEST CHANCE OF
PRECIPITATION IS LATE SATURDAY NIGHT INTO SUNDAY MORNING ACROSS THE
WESTERN HALF OF THE FORECAST AREA, WITH THE DAYTIME HOURS SUNDAY
ENCOMPASSING THE BEST CHANCES FOR THE EASTERN HALF OF THE FORECAST
AREA. SEVERE STORM CHANCES ON SUNDAY ALSO APPEAR LOW DUE TO THE
EARLIER ARRIVAL OF THE FRONT (LESS CHANCE FOR DIURNAL
DESTABILIZATION), AND WEAK SHEAR (BULK SHEAR GENERALLY LESS THAN 25
KTS).
OUTSIDE OF HAVING THIS FRONT IN THE VICINITY, THE REMAINDER OF THE
PRE AND POST FRONTAL PORTION OF THIS FORECAST IS EXPECTED TO BE
DOMINATED BY HIGH PRESSURE AT THE SURFACE, AND NEUTRAL TO WEAKLY
CYCLONIC FLOW ALOFT. THIS PATTERN SHOULD KEEP TEMPERATURES AT LEAST
SLIGHTLY BELOW NORMAL FOR LATE AUGUST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1149 PM CDT FRI AUG 21 2015
VFR AVIATION WEATHER CONDITIONS EXPECTED THROUGH THE 06Z TAF
VALID TIME, BUT AFTERNOON AND EVENING CLOUDS WILL BECOME MORE
PROMINENT AS MID AND UPPER LEVEL MOISTURE INCREASES AHEAD OF AN
APPROACHING COLD FRONT. CLEAR SKIES ARE EXPECTED TONIGHT AND
TOMORROW MORNING, ALTHOUGH SOME LIGHT MVFR FOG COULD DEVELOP IN
EASTERN IL LATE TONIGHT NEAR CMI, PER THE LATEST HRRR OUTPUT.
LOOK FOR WINDS TO BE S-SW AT 5-7KT THE REST OF THE NIGHT, THEN
INCREASE FROM THE SE SATURDAY MORNING, WITH GUSTS TO 16-18KT FOR
THE NW TERMINALS OF PIA/BMI.
EVEN THOUGH THE NEXT COLD FRONT IS SLATED TO ARRIVE LATE SATURDAY
NIGHT INTO SUNDAY MORNING, FORECAST SOUNDINGS ARE POINTING TOWARD
AN OVERCAST SKY /5K FT/ BEFORE 06Z AT PIA AND BMI, AND POSSIBLY
10K FT CEILING ELSEWHERE. RAIN SHOULD HOLD OFF UNTIL AFTER 06Z,
BUT CAN`T RULE OUT SPRINKLES LATE IN THIS TAF PERIOD.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHIMON
SHORT TERM...07
LONG TERM...BAK
AVIATION...SHIMON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
344 AM CDT SAT AUG 22 2015
.SHORT TERM /TODAY/...
ISSUED AT 327 AM CDT SAT AUG 22 2015
A VERY POTENT 500MB TROUGH WILL CONTINUE TO DEEPEN THROUGHOUT THE
DAY AS EJECTS OUT OF THE NORTHERN ROCKIES INTO THE DAKOTAS THIS
AFTERNOON. THE SURFACE LOW LOOKS TO DEVELOP AND STRENGTHEN OVER
THE EASTERN PORTIONS OF THE DAKOTAS WITH A SHARP COLD FRONT
EXTENDING SOUTHWARD INTO NEBRASKA BY MIDDAY TODAY AND THEN
TRANSITION SOUTHEAST INTO NORTHWEST IOWA LATE IN THE PERIOD.
TROUGH BECOMES NEGATIVELY TILTED BY AROUND 00Z SUNDAY. THERE IS A
LOW POTENTIAL FOR SOME ELEVATED STORMS TO TRY AND DEVELOP OVER
WESTERN TO NORTHWEST PORTIONS OF IOWA AHEAD OF THE COLD
FRONT...BUT WITH A VERY STRONG CAP IN PLACE...HAVE LOW CONFIDENCE
WITH ANYTHING WIDESPREAD AND THUS ANY SEVERE WX PRIOR TO THE FROPA
AND LEFT FORECAST DRY UNTIL 21Z.
THE HIRES 22.00Z ARW/NMM...22.00Z NSSL-WRF...22.05Z HRRR AND COUPLE
MEMBERS OF THE 22.03Z HOPWRF ALL SUGGEST CONVECTIVE INITIATION B/T
21-23Z OVER FAR NORTHWEST IOWA. ACROSS THE WEST TO NORTHWEST
SECTIONS OF THE FORECAST AREA...DEEP LAYER SHEAR INCREASES TO 40-45
KNOTS PAST 21Z WITH 0-1KM AND 0-3KM SHEAR BOTH IN THE 20-30 KNOT
RANGE. STRONG SURFACE BASE CAPE INCREASES TO 3000-3800 J/KG WITH
STEEP LAPSE RATES IN THE 7.5-8 C/KM RANGE. LCL HEIGHTS AROUND 600M
IN THE WARM SECTOR AND EXPECTING DISCRETE SUPERCELLS WITH INITIATION
THIS AFTERNOON. HOWEVER...THE MOST LIKELY SCENARIO IS STORMS LOOK TO
QUICKLY EVOLVE INTO QLCS SQUALL LINE BY TIME THEY MOVE INTO THE
FORECAST AREA. THERE IS A POTENTIAL FOR SUPERCELLS TO CREEP INTO THE
FAR WESTERN TO NORTHWESTERN EDGES OF THE FORECAST AREA (DENISON TO
ESTHERVILLE LINE) PRIOR TO THE SQUALL LINE EVOLUTION...AND HAVE POPS
INTRODUCED BY 21Z. ALL MODES OF SEVERE WEATHER POSSIBLE LATE THIS
AFTERNOON...WITH TORNADIC AND LARGE HAIL POTENTIAL UPON INITIATION
AND THEN MORE LIKELY DAMAGING WINDS WITH THE SUPERCELLS EVOLVING
INTO QLCS. CERTAINLY CANNOT RULE TORNADIC POTENTIAL WITHIN THE QLCS
LATE IN THE PERIOD. REGARDLESS...HAVE SEVERE MENTIONED PAST 21Z IN
THE FAR NORTHWEST TO COINCIDE WITH SPC ENHANCED RISK AREA.
.LONG TERM /TONIGHT THROUGH FRIDAY/...
ISSUED AT 327 AM CDT SAT AUG 22 2015
ONGOING SEVERE WEATHER AND HEAVY RAINFALL EXPECTED EARLY IN THE
FIRST PERIOD. SEVERAL FACTORS POINT TO A ROBUST LINE OF CONVECTION
THIS EVENING. A STRONG COLD FRONT WITH IMPRESSIVE SFC CONVERGENCE
...STRONG INSTABILITY/HIGH PRECIPITABLE WATER AND APPROACHING H500
WAVE WILL COMBINE TO ENHANCE CONVECTION THROUGH AT LEAST 06Z. MAIN
CONCERNS AFTER 02Z WILL BE THREAT FOR WIND/HAIL AND HEAVY RAINFALL.
GFS BUFR SOUNDINGS AT 00Z SHOW 0-3KM SRH ABOUT 200-300 J/KG AT
KDSM AS THE LINE REACHES CENTRAL IA AT THAT TIME WITH STORM RELATIVE
HELICITY WEAKENING TOWARD 06Z IN THE SOUTHEAST. SBCAPE IS PROGGED
TO BE 2750 WITH LCL OF NEAR 692M/2000FT. INITIALLY THE THREAT
THROUGH ABOUT I35 WILL STILL INCLUDE THE RISK OF A TORNADO THOUGH
ANY DISCRETE SUPERCELLS IN THE LATE AFTERNOON SHOULD BE EVOLVING
INTO A MORE LINEAR AND ACCELERATING LINE OF STORMS AS IT MOVES
MORE RAPIDLY SOUTHEAST WITH TIME. THROUGH THE EVENING HOURS THE
THREAT FOR SEVERE WEATHER WILL GRADUALLY WEAKEN AS BOTH CAPE AND
HELICITY BEGIN TO LESSEN WITH TIME. THE OTHER CONCERN WITH THIS
EVENT WILL BE BRIEF BUT VERY HEAVY RAINFALL. SUBJECTIVE 00Z
SATURDAY H850 ANALYSIS THIS EVENING SHOWS A +15C PLUME OF MOISTURE
FROM THE TEXAS COAST UP INTO CENTRAL/WESTERN NEBRASKA. THE GFS IS
FORECASTING PRECIPITABLE WATER OF UP TO 1.7 INCHES ALONG THE
BOUNDARY IN WESTERN IA AT 18Z...AND A MORE BROAD AREA OF 1.75 TO
AROUND 2 INCHES FROM CENTRAL THROUGH SOUTHEAST IA FROM 00-06Z
TONIGHT. THIS COMBINED WITH AN EXPECTED WARM CLOUD DEPTH OF
3600-3800M (>12KFT) OVER WESTERN IOWA...INCREASING TO OVER 4000M
(>13KFT) FROM TAMA TO DECATUR COUNTY BY 06Z WILL PROMOTE
INCREASINGLY EFFICIENT RAINFALL AS THE LINE BECOMES MORE ORGANIZED
AND 0-6KM BULK SHEAR 50-60KTS BEHIND THE BOUNDARY CATCHES UP TO
THE LINE FROM 03-06Z. NMM MOISTURE CONVERGENCE AND MOISTURE
TRANSPORT VECTORS ARE BOTH MAXIMIZED AT THIS TIME OVER
CENTRAL/SOUTHERN IOWA. FOR NOW AM ANTICIPATING AT LEAST A PERIOD
OF 1-2 HOURS OF 1-2 INCH RAINFALL/HOUR MAINLY FROM 03-06Z FROM
NEAR AMES SOUTHWEST TO CRESTON/LAMONI OR GENERALLY SOUTH OF
HIGHWAY 30 AND ALONG AND WEST OF I35. CURRENT 1HR GRIDDED FLASH
FLOOD GUIDANCE IS RUNNING ABOUT 1.75 TO NEARLY 2 INCHES OVER MOST
OF THIS REGION AND HIGH ENOUGH TO AVOID A HEADLINE FOR FLASH
FLOODING. HOWEVER...THE TIMING OF THE RAINFALL AND LIKELIHOOD THAT
IT WILL FALL DURING THE LATE EVENING HOURS ON A WEEKEND EVENING
OVER URBAN AREAS IS A CONCERN. PONDING OF WATER AND SOME STREET
FLOODING COULD BE A PROBLEM ACROSS MOSTLY URBAN AREAS. EVENTUALLY
THE LINE WILL BE NEARLY OUT OF THE AREA BY 10-13Z AS THE FORWARD
MOTION TAKES IT INTO NORTHERN MO AND SOUTHEAST IA BY 13Z.
THE REMAINDER OF THE FORECAST IS FAIRLY BENIGN. ONCE THE VIGOROUS
H500 TROUGH MOVE EAST INTO THE GREAT LAKES SUNDAY INTO MONDAY MUCH
COOLER AND DRIER WEATHER WILL BE EXPECTED FROM SUNDAY THROUGH
TUESDAY. A GRADUAL WARMING TREND IS EXPECTED FROM WEDNESDAY THROUGH
FRIDAY WITH A WEAK WAVE IMPACTING THE REGION ON THURSDAY. HIGHS WILL
WARM FROM THE LOWER TO MID 70S EARLY IN THE PERIOD TO THE MID 70S TO
LOWER 80S LATE IN THE PERIOD. LOWS RECOVER FROM THE 40S/50S TO THE
50S/60S LATER IN THE PERIOD.
&&
.AVIATION...22/06Z
ISSUED AT 1158 PM CDT FRI AUG 21 2015
LOW VFR OR MVFR CEILINGS MAY ENTER WESTERN SITES NEAR 12Z...THOUGH
HAVE NOT INCLUDED MENTION ATTM DUE TO UNCERTAINTIES. WINDS WILL
REMAIN SOUTHERLY AND WILL BE GUSTY DURING THE DAY SATURDAY WITH
GUSTS UP TO 30KTS POSSIBLE. BOUNDARY WILL BEGIN TO IMPACT SITES
NEAR 00Z...BRINGING CHANCES FOR TSRA TO SITES. TSRA MAY BRING
MVFR OR LOWER CEILINGS AND VISIBILITIES FOR END OF PERIOD...WITH
WINDS BECOMING WESTERLY BEHIND BOUNDARY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS TOPEKA KS
320 AM CDT SAT AUG 22 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SAT AUG 22 2015
THIS MORNING, MULTIPLE PIECES OF EMBEDDED VORTICITY MAXIMA IN THE
MID LEVELS WERE PROGRESSING EASTWARD THROUGH THE PLAINS. STRONGER
ISENTROPIC UPGLIDE HAD DEVELOPED A CLUSTER OF STORMS OVER FAR
NORTHERN OK INTO SOUTHEAST KS. THERE IS A SMALL CHANCE THE REMNANT
OUTFLOW FROM THIS CLUSTER WILL DEVELOP SCT SHOWERS/ISO THUNDER
OVER FAR EAST CENTRAL KS THROUGH SUNRISE. WHAT IS MORE LIKELY IS
DRY CONDITIONS AND OVERCAST SKIES THROUGH THE MORNING BEFORE
SUBSIDENCE CLEARS CLOUD DECK EASTWARD BY THE AFTERNOON. HIGH TEMPS
TODAY ARE STILL ON TRACK TO BE A FEW DEGREES WARMER IN THE UPPER
80S TO LOWER 90S. RAISED DEWPOINT TEMPS THIS AFTERNOON AS MOST
SHORT TERM GUIDANCE ADVECTS READINGS IN THE LOWER 70S, ESPECIALLY
OVER FAR EASTERN KANSAS. THE RESULT OF THE HIGHER MOISTURE WILL
LIKELY ALLOW FOR HIGHER INSTABILITY TO BUILD UNDER A DECENT EML
THROUGH THE AFTERNOON. THIS CAPPING INVERSION SHOULD INHIBIT
DEVELOPMENT UNTIL THE COLD FRONT APPROACHES FROM NEBRASKA. BELIEVE
THE NAM REMAINS ON THE HIGH BIAS WITH MID 70S DEWPOINTS AND CAPE
PEAKING NEAR 4000 J/KG, HOWEVER WOULD NOT BE SURPRISED TO SEE MOST
AREAS IN THE 2500 TO 3500 J/KG CATEGORY BY 4 PM. GIVEN THE SETUP,
SEVERE WEATHER POTENTIAL REMAINS LIKELY BEGINNING LATE THIS
AFTERNOON INTO THE EVENING HOURS. DETAILS TO FOLLOW.
WITH THE STRONG CAPPING INVERSION IN PLACE DURING THE AFTERNOON, THE
MAIN AREA OF ASCENT TO LIFT THESE SFC PARCELS WILL FOCUS ALONG THE
COLD FRONT THAT IS CURRENTLY TRACKING SOUTHEAST FROM NORTHERN CO TO
CENTRAL SD. THIS FRONT WILL QUICKLY TRAVERSE NEBRASKA THROUGH THE
DAY, WITH ALL GUIDANCE DEVELOPING QPF NEAR THE FRONT BETWEEN 5 PM
AND 7 PM ACROSS COUNTIES NEAR THE KS AND NE BORDER. SHORT AND MID
TERM GUIDANCE IS STILL IN GOOD AGREEMENT IN FORMING A LINE OF
CONVECTION THAT QUICKLY RACES SOUTHEAST THROUGH NORTHEAST KS DURING
THE EVENING AND OVERNIGHT PERIODS. RAP AND NAM FORECAST SOUNDINGS
SHOW NICELY CURVED HODOGRAPHS WITH 0-3 KM SRH VALUES AT OR ABOVE 150
M2/S2 WHILE LOW LEVEL SHEAR MAXIMIZES NEAR 20 KTS. IF STORMS ARE
ABLE TO FORM IN THIS ENVIRONMENT DURING THE LATE AFTERNOON/EARLY
EVENING TIME FRAME, THERE IS A POSSIBILITY FOR AN ISOLATED TORNADO
TO FORM, ESPECIALLY LOCATIONS NORTH OF INTERSTATE 70 WHERE BETTER
WIND PROFILES EXIST. OTHERWISE, STEEP MID LEVEL LAPSE RATES AND
AMPLE MUCAPE WILL CARRY THE SEVERE POTENTIAL FOR LARGE HAIL AND
DAMAGING WIND GUSTS ACROSS THE ENTIRE CWA. BRIEF HEAVY RAINFALL IS
EXPECTED WITH SOME AREAS PICKING UP OVER AN INCH BY SUNRISE. THE
MAIN CHANGE WITH THIS UNSEASONABLY STRONG SYSTEM IS ADJUSTING WINDS
AND TEMPS AS THE SPEED OF THE FRONT IS A BIT FASTER THAN PREVIOUS
RUNS. THIS MAY ALSO FURTHER HEIGHTEN THE STRONG WIND POTENTIAL.
SUBSIDENCE AND CLEAR SKIES MOVE IN QUICKLY BEHIND THE LINE, OPTING
FOR LOWER TEMPS IN THE LOWER 50S NORTH TO LOW 60S SOUTH SAT
MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT AUG 22 2015
THE COLD FRONT IS EXPECTED TO BE THROUGH THE FORECAST AREA BY
SUNDAY MORNING. THEREFORE THE PRECIP SHOULD BE OVER AS COLD AIR
ADVECTION STABILIZES THE ATMOSPHERE. HIGHS SUNDAY SHOULD BE IN
THE MID AND UPPER 70S DUE TO THE COLD AIR ADVECTION. MONDAY
MORNING SHOULD BE THE COOLEST AS THE CENTER OF THE SURFACE RIDGE
PASSES THROUGH THE AREA. WITH CLEAR SKIES AND LIGHT WINDS, LOWS
ARE EXPECTED TO DROP TO THE LOWER 50S OR AROUND 50.
NEXT WEEK SHOULD BE QUIET FOR THE MOST PART. MODELS CONTINUE TO
AMPLIFY AN UPPER RIDGE JUST WEST OF THE FORECAST AREA. THIS
BLOCKING PATTERN MAKES IT DIFFICULT FOR ANY WAVE OF SUBSTANCE TO
AFFECT THE FORECAST AREA, AND THERE IS LITTLE CONFIDENCE IN THE
GFS SOLUTIONS AND THE TRANSIENT VORT MAXIMUM IT DEVELOPS. HAVE
LEANED MORE TOWARDS THE ECMWF WHICH AT A LOWER RESOLUTION, TENDS
TO KEEP WEAK NORTHWESTERLY FLOW WITHOUT THE SMALL SCALE
PERTURBATIONS THROUGH MID WEEK. BY FRIDAY, THE ECMWF/GFS/CANADIAN
SEEM TO BRING A LITTLE BETTER DEFINED WAVE OVER THE TOP OF THE
UPPER RIDGE WITH A WEAK BOUNDARY. BECAUSE OF THIS HAVE SOME SMALL
POPS IN FOR THURSDAY NIGHT AND FRIDAY. MODELS SHOW A SIMILAR
AIRMASS RESIDING OVER THE AREA THROUGH THE WEEK. SO AFTER A COOL
START ON MONDAY, TEMPS SHOULD MODERATE WITH RISING HEIGHTS. HIGHS
ARE FORECAST TO BE IN THE 80S WHILE LOWS GRADUALLY TREND WARMER
FROM THE MID 50S TUESDAY TO THE MID 60S FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1145 PM CDT FRI AUG 21 2015
LOW STRATUS ASSOCIATED WITH OUTFLOW FROM CONVECTION OVER SOUTH
CENTRAL KS IS MOVING NORTHWARD TOWARD TERMINALS. WILL CARRY THIS
OVERNIGHT ALONG WITH SOME HAZE BUT BREAKS UP QUICKLY IN THE
MORNING. FRONT MOVES IN LATE IN THE PERIOD BUT CONFIDENCE IS HIGH
ENOUGH TO START A PREVAILING GROUP.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BOWEN
LONG TERM...WOLTERS
AVIATION...67
AREA FORECAST DISCUSSION
NWS CARIBOU ME
416 AM EDT SAT AUG 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION AND STALL ACROSS DOWNEAST MAINE
THIS AFTERNOON WHILE HIGH PRESSURE BUILDS IN BRIEFLY ACROSS THE
NORTHERN AREAS. THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS
A WARM FRONT SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 07Z...HEAVY RAIN SHIFTED INTO SE AROOSTOOK COUNTY AND
EASTWARD INTO WESTERN NEW BRUNSWICK. ANOTHER SMALLER BATCH OF RAIN
HAD MOVE INTO SOUTHERN PISCATAQUIS COUNTY, BUT NOT NEARLY AS
HEAVY AS FRIDAY NIGHT. SURFACE ANALYSIS HAD THE COLD FRONT SLOWLY
WORKING ITS WAY E ACROSS WESTERN MAINE. AREAS OF FOG ALONG THE
IMMEDIATE COAST THIS MORNING. THE LATEST RUN OF THE HRRR KM AND
RAP HAD A GOOD HANDLE ON THINGS ATTM KEEPING HIGHER POPS OVER
EASTERN AREAS THIS MORNING INTO THE AFTERNOON AS THE FRONT SAGS ESE
AND THEN STALLS ACROSS DOWNEAST MAINE COAST. LLVL CONVERGENCE AND
SOME WEAK MID LEVEL FORCING WILL ALLOW FOR SHOWERS TO CONTINUE
ACROSS THE AFOREMENTIONED AREAS INTO EARLY EVENING. INSTABILITY IS
THERE ESPECIALLY FOR WASHINGTON AND HANCOCK COUNTY. SOUNDING DATA
SUPPORTED SBCAPES OF 500-800 JOULES AND LIS DOWN TO -3 W/PWATS OF
1.8+ INCHES. LOW/MID LEVEL LAPSE RATES OF 6.2 C/KM EXPECTED, SO
TSTM POTENTIAL IS THERE. HIGH FREEZING LEVELS AND WBZS(14K FT)
WILL ALLOW FOR ANY TSTMS TO CONTAIN HEAVY RAINFALL. 0-6KM SHEAR
AROUND 12 KTS W/SW FLOW THROUGH 700MBS WILL ALSO ALLOW ANY STORMS
TO TRAIN OVER THE SAME AREAS. THIS ALL HINGES ON HEATING
POTENTIAL WHICH COULD BE DELAYED FOR A WHILE. THEREFORE, DECIDED
TO CARRY TSTMS FOR THE DOWNEAST ESPECIALLY HANCOCK AND WASHINGTON
COUNTY BUT LEFT OUT ENHANCED WORDING ATTM. WILL TAKE ANOTHER LOOK
AT THINGS W/6 AM UPDATE. FURTHER NORTH ACROSS PISCATAQUIS AND
AROOSTOOK COUNTY, DRIER W/SOME PARTIAL CLEARING EXPECTED.
FOR TONIGHT, THE FRONT LOOKS AS THOUGH IT TRIES TO BUCKLE BACK TO
THE NORTH AS A WEAL UPPER LOW LIFTS ACROSS THE WESTERN ATLC. SHOWERS
EXPECTED TO EDGE A BIT FURTHER NNE INTO CENTRAL PENOBSCOT AND
NORTHERN WASHINGTON COUNTY. FURTHER N AND W., DRIER AND A BIT
COOLER OVERNIGHT. FOG LOOKS TO BE A THREAT OVERNIGHT ESPECIALLY
WHERE RAINFALL OCCURRED. TEMPERATURES ARE EXPECTED TO BE IN THE
UPPER 50S TO LOWER 60S NORTH AND WEST W/MID 60S FOR THE DOWNEAST
AND COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
LOW PRESSURE WILL MEANDER ACROSS THE NW ATLANTIC DURING SUNDAY AS
AN AREA OF HIGH PRESSURE MOVES EAST ACROSS THE MARITIMES. A MOIST
EAST TO SOUTHEAST FLOW AROUND THESE SYSTEMS WILL KEEP A CHANCE OF
SHOWERS AND PERHAPS AN AFTERNOON TSTM TO MAINLY PORTIONS OF
CENTRAL AND DOWN EAST MAINE SUNDAY AFTERNOON. THE LOW WILL SLOWLY
START TO DRIFT EAST MONDAY NIGHT THROUGH TUESDAY. MOISTURE
ASSOCIATED WITH AN APPROACHING TROF FROM THE GREAT LAKES REGION
WILL CONTINUE THE THREAT OF SHOWERS THROUGH MONDAY ALONG WITH THE
CHANCE FOR A FEW AFTERNOON THUNDERSTORMS. HIGH TEMPERATURES BOTH
SUNDAY AND MONDAY WILL BE IN THE MID TO NEAR 80 DEGREES. LOWS
SUNDAY NIGHT WILL BE IN THE 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
UNSETTLED WEATHER CONDITIONS WILL PERSIST THROUGH THURSDAY AS A
TROF OF LOW PRESSURE TO OUR WEST SLOWLY CROSSES THE REGION THROUGH
THURSDAY. THIS WILL BRING A CONTINUED THREAT FOR SHOWERS THROUGH
THURSDAY. WE SHOULD START TO DRY OUT A BIT BY THURSDAY NIGHT AND
FRIDAY BEFORE ANOTHER SYSTEM BRINGS THE CHANCE FOR SHOWERS BY NEXT
WEEKEND.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MVFR FOR KBGR AND IFR/LIFR KBHB THIS MORNING W/VFR
ACROSS THE NORTHERN TERMINALS. SOME IMPROVEMENT EXPECTED FOR KBHB
TO MVFR LATER THIS AFTERNOON. KBGR COULD DROP BACK TO IFR THIS
MORNING BEFORE RECOVERING BACK TO MVFR AND POSSIBLY VFR THIS
AFTERNOON. ACROSS THE NORTH, PERIODS OF MVFR EXPECTED THIS MORNING
W/A RECOVERY TO VFR. FOG POTENTIAL FOR TONIGHT COULD ALLOW
CONDITIONS TO GO TO MVFR NORTH OF KBHB WHILE KBHB DOWN TO IFR.
SHORT TERM: CONDITIONS WILL VARY AT TIMES THROUGH THE PERIOD FROM
VFR DOWN TO IFR IN SHOWERS AND PATCHY MAINLY NIGHTTIME FOG.
&&
.MARINE...
NEAR TERM: NO HEADLINES EXPECTED THIS TERM. SSE SWELL OF 2 FT OUT
THERE ATTM AND A SLIGHT BUILD IN WAVE HEIGHTS EXPECTED TONIGHT.
WINDS WILL REMAIN 10 KTS OR LESS W/FOG A NUISANCE TO NAVIGATION.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS THROUGH THE PERIOD.
&&
.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
103 AM EDT SAT AUG 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT BEFORE HIGH PRESSURE
BUILDS IN BRIEFLY FOR SATURDAY. THE COLD FRONT WILL THEN RETURN
NORTH AS A WARM FRONT SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1245 AM UPDATE: HEAVY RAIN AXIS EXTENDING FROM NE AROOSTOOK COUNTY
DOWN THROUGH PENOBSCOT AND PISCATAQUIS COUNTY HAD SHIFTED E PER
THE LATEST RADAR LOOP. TSTMS HELPING W/TEH HEAVY RAINFALL
W/REPORTS OF OVER 5 INCHES IN GUILFORD SINCE LATE AFTERNOON.
DECIDED TO MOVE RAIN AXIS A BIT EASTWARD MATCHING UP W/THE RADAR
AND THE LATEST RUN OF THE HRRR 3KM MODEL. SOME ROADS IN GUILFORD
WERE STARTING TO FLOOD AND A FLASH FLOOD WARNING WAS ISSUED
EARLIER FOR THIS REGION. THE FLOOD ADVISORY REMAINS IN EFFECT FOR
SOUTHERN PISCATAQUIS COUNTY UNTIL 2AM .
BY DAYBREAK THE FRONT WILL STRETCH FROM ROUGHLY HOULTON TO DOVER-
FOXCROFT. AREAS SOUTH OF THIS BOUNDARY WILL ONCE AGAIN BE IN VERY
MUGGY AIR, WITH AREAS OF LOCALLY DENSE FOG EXPECTED. NORTH OF THE
FRONT, SLIGHTLY DRIER AIR WILL BEGIN TO WORK IN LATE TONIGHT.
HOWEVER, THERE WILL BE ENOUGH LINGER LOW-LEVEL MOISTURE,
ESPECIALLY WHERE RAIN FALLS, FOR FOG TO DEVELOP.
THE FRONT WILL CONTINUE ITS SLOW TREK TOWARD THE COAST LATER TODAY.
SHOWERS WILL ONCE AGAIN BE THE RULE AHEAD OF THE FRONT, ALONG WITH
ISOLATED THUNDERSTORMS. BEHIND THE FRONT, DRIER AIR WILL ALLOW FOR
PARTLY SUNNY SKIES AND SLIGHTLY LOWER DEWPOINTS. HIGHS WILL MAINLY
BE IN THE MID AND UPPER 70S AREAWIDE, A LITTLE COOLER ALONG THE
IMMEDIATE COAST.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
WHATS LEFT OF THE COLD FRONT WILL BECOME STATIONARY JUST OFF THE
DOWNEAST COAST SAT NGT INTO SUN WHILE SFC LOW PRES OVR THE ATLC
WELL E OF THE MID ATLC STATES SLOWLY MEANDERS EWRD AND WEAKENS.
THIS WILL LEAVE THE FA IN A WEAK FLOW REGIME WHERE INITIALLY LEFT
OVR LLVL MOISTURE WILL CONTRIBUTE TO A MSLY DIURNALLY DRIVEN CHANCE
OF SHWRS/TSTMS MSLY OVR THE SE PTN OF THE FA SUN AFTN INTO EVE.
SHWRS AND TSTMS SHOULD DIMINISH LATE SUN NGT WITH THE LOSS OF
HTG.
THE POTENTIAL OF SHWRS AND A CHC OF TSTMS WILL XTND FURTHER N TO
CVR ALL OF THE FA BY MON AFTN AS WEAK S/WV ENERGY FROM A DEEP
UPPER TROF OVR THE MIDWEST REACHES THE FA. FOR BOTH SUN AFTN/EVE
AND MON AFTN/ERLY EVE...FCST LOW END MAX SBCAPES SUPPORTS A CHC OF
TSTMS...WITH LCLY HVY RN THE MAIN CONCERN ATTM. WILL HOLD OFF ON
ANY ENHANCED TSTM WORDING FOR NOW WITH SHWRS/TSTMS XPCTD IN THE
NEAR TERM. POPS OVR THE FA WERE DERIVED FROM BLENDED MODEL/WPC
6 HRLY QPF AMOUNTS...WITH THE HIGHEST LIKELY POPS XPCTD ACROSS
NRN/CNTRL PTNS OF THE FA MON AFTN.
OTHERWISE...LATE NGT PATCHY FOG IS XPCTD BOTH SAT NGT AND SUN
NGT OVR THE FA...MOST LIKELY LASTING LONGEST INTO THE MORN OVR
DOWNEAST AREAS. BOTH HI AND LOW TEMPS WILL CONT ABV NORMAL WITH
DWPT TEMPS MSLY REMAINING IN THE 60S FOR ALL...XCPT HI TRRN LCTNS
THRU THE SHORT TERM.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A RETURN OF A LONGWAVE TROUGH IN THE EAST WILL RESULT IN SLIGHTLY
COOLER AND MORE UNSETTLED CONDITIONS BEGINNING DURING THE MIDWEEK
PERIOD. A FRONTAL BOUNDARY STALLED OVER THE AREA WILL BRING MOSTLY
CLOUDY CONDITIONS MONDAY NIGHT INTO TUESDAY WITH SOME SHOWERS
POSSIBLE, AND MAYBE A FEW SCATTERED THUNDERSTORMS. THE BEST
CHANCE FOR SHOWERS WILL BE OVER THE NORTH. SHOWERS WILL CONTINUE
TO BE POSSIBLE WEDNESDAY, MAINLY OVER THE NORTH, WHILE DOWNEAST
AREAS HAVE PARTIAL CLEARING ON WEDNESDAY AS LOW PRESSURE TRACKS
WELL TO OUR NORTH AND THE FRONTAL BOUNDARY BEGINS TO LIFT NORTH A
LITTLE. SHORTWAVE RIDGING SHOULD THEN BRING CLEARING THROUGHOUT
THE AREA ON THURSDAY AS THE FRONT MOVES AWAY TO THE NORTH. FRIDAY
MAY BEGIN WITH SOME SUNSHINE OVER THE REGION. ANOTHER TROUGH
APPROACHING FROM THE WEST WILL THEN BRING INCREASING CLOUDS AND A
CHANCE FOR SHOWERS, MAINLY NORTH, LATE FRIDAY. SHOWERS WILL BE
POSSIBLE FRIDAY NIGHT WITH A FRONTAL PASSAGE BEFORE DRY AIR
BRINGS A RETURN FOR SOME SUNSHINE FOR THE WEEKEND.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: 11PM UPDATE: KBHB AT LIFR CIGS, AND FOG APPEARS TO BE
ROLLING IN WITH VIS DOWN TO IFR LEVELS. MAINTAIN LIFR CIGS AND IFR
VIS THRU 13Z, WITH IFR CIGS THROUGH 17Z. KBGR ALSO HAS LIFR CIGS
AND VIS IS DROPPING TOWARD IFR AS WELL. KEEP IFR CONDITIONS AT
KBGR THROUGH 16Z, WITH VIS IMPROVING BY 13Z. NORTHERN TERMINALS
HAVE DRIFTED IN AND OUT OF IFR VIS AND CIGS WITH BOUTS OF HEAVY
RAIN, BUT FOR NOW ONLY BRING KHUL DOWN TO IFR CIGS, WITH OTHER 3
TERMINALS DOWN TO MVFR THRU THE NIGHT.
WIDESPREAD IFR/LOCAL LIFR EXPECTED KBGR, AND KBHB IN
FOG THIS EVENING AND OVERNIGHT. FURTHER NORTH, MVFR WITH
OCCASIONAL IFR DUE TO SHOWERS IS EXPECTED. HOWEVER, LOCALLY LOWER
CONDITIONS IN FOG IS ALSO POSSIBLE AT THE NORTHERN SITES.
CONDITIONS WILL IMPROVE AT THE NORTHERN TERMINALS DURING THE DAY
SATURDAY, BUT IFR CONDITIONS WILL LIKELY HOLD ON A GOOD PART OF
THE MORNING, ESPECIALLY AT KBHB. SHOWERS AND ISOLATED
THUNDERSTORMS ARE ALSO POSSIBLE AT KHUL, KBGR, AND KBHB TOMORROW,
WITH LOCAL MVFR POSSIBLE IN HEAVIER ACTIVITY.
SHORT TERM: IFR LATE NGT INTO ERLY MORN BOTH SAT NGT/SUN MORN AND
SUN AFTN/MON MORN ALL TAF SITES. OTHERWISE MVFR TO LOW VFR CLGS...AND
ATTMS MVFR VSBYS DURG THE AFTN AND EVE HRS IN TSTMS AND HEAVIER
SHWRS.
&&
.MARINE...
NEAR TERM: AREAS TO WIDESPREAD DENSE FOG EXPECTED TO PERSIST
OFFSHORE AS THE MAIN HAZARD IN NEAR TERM FOR THE MARINE ZONES.
WINDS REMAIN LIGHT AND ONSHORE, WITH COMBINED SEAS OF 2 TO 3 FT,
MOSTLY SWELL.
SHORT TERM: NO HDLNS ANTICIPATED...WITH AT LEAST PATCHY MARINE FOG
CVRG POSSIBLE SAT NGT AND SUN NGT. WV HTS WILL MSLY BE 3 TO 4 FT
OVR THE OUTER MZS WATERS WITH 1 TO 2 FT ACROSS THE INNER BAY/HARBOR
WATERS...WITH A MDT SWELL COMPONENT. KEPT CLOSE TO WW3 GUIDANCE
THIS UPDATE...WITH ABOUT A 25 PERCENT REDUCTION ALG THE IMMEDIATE
COAST.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 AM EDT SAT AUG 22 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 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 127 AM EDT SAT AUG 22 2015
DRY AIR MASS WILL LINGER AT THE LOW LEVELS THRU THIS FCST PERIOD...
RESULTING IN VFR CONDITIONS AT KIWD/KCMX/KSAW. ONE ITEM OF NOTE WILL
BE THE THICK SMOKE LAYER WELL ALOFT OVER THE AREA THAT HAS
ORIGINATED FROM THE FOREST FIRES IN THE PACIFIC NW. OTHERWISE...
TIGHTENING PRES GRADIENT BTWN HIGH PRES OVER THE LOWER GREAT LAKES
VCNTY AND A VIGOROUS LOW PRES SYSTEM DEVELOPING OVER THE DAKOTAS
WILL RESULT IN LLWS OVERNIGHT AT ALL TERMINALS. WITH ONSET OF
DAYTIME HEATING...WINDS WILL BECOME GUSTY FROM THE S. HIGHEST GUSTS
TO AROUND 30KT WILL OCCUR THIS AFTN AT KIWD/KSAW. APPROACHING COLD
FRONT ASSOCIATED WITH THE AFOREMENTIONED LOW PRES SYSTEM WILL SPREAD
SHRA AND PERHAPS SOME THUNDER TO NEAR KIWD AT THE END OF THE FCST
PERIOD.
&&
.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...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
250 AM PDT SAT AUG 22 2015
.SYNOPSIS...HAZY CONDITIONS OVER MUCH OF THE AREA WILL IMPROVE OVER
THE WEEKEND AS SMOKE FROM CALIFORNIA WILDFIRES IS STEERED TOWARD
CENTRAL NEVADA. A SHALLOW PUSH OF MOISTURE WILL LEAD TO SLIGHT
CHANCES FOR THUNDERSTORMS OVER MAINLY THE HIGHER TERRAIN OF LINCOLN
AND NORTHERN MOHAVE COUNTIES THIS WEEKEND. DEEPER MOISTURE ARRIVES
EARLY NEXT WEEK AND COULD LINGER THROUGH MID WEEK WHICH WILL RESULT
IN INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS. &&
.SHORT TERM...THROUGH MONDAY NIGHT.
ANOTHER SEASONABLY WARM AND MOSTLY DRY DAY IS EXPECTED ACROSS THE
REGION TODAY. ONE NOTABLE CHANGE OVER YESTERDAY IS THAT DESPITE A
MODEST MOISTURE INCREASE AND INSTABILITY ACROSS THE AREA
YESTERDAY...NO THUNDERSTORMS WERE ABLE TO FORM DUE TO LARGE SCALE
SUBSIDENCE OVER THE REGION. THINGS TODAY LOOK A LITTLE MORE
PROMISING AS A WEAK SHORTWAVE WILL BE LIFTING ACROSS THE AREA THIS
AFTERNOON AND INTERACTING WITH SOME OF THE MARGINAL INSTABILITY THAT
IS IN PLACE ACROSS MAINLY LINCOLN AND NORTHERN MOHAVE COUNTIES.
EARLY MORNING RUNS OF THE HRRR BREAK OUT ISOLATED STORMS ACROSS
LINCOLN COUNTY BETWEEN 1PM AND 2PM AND WITH THE WEAK SHORT WAVE
PUSHING THROUGH...THERE SHOULD BE JUST ENOUGH LIFT TO SUPPORT THIS.
THE LOWER ATMOSPHERE ESPECIALLY IN LINCOLN COUNTY IS STILL A BIT
DRY...SO GUSTY DOWNBURST WINDS AND LIGHTNING ACCOMPANIED BY LITTLE
RAIN WILL BE THE PRIMARY THREATS. OTHERWISE...FORECAST OUTSIDE OF
THE ABOVE MENTIONED AREAS WILL BE DRY.
ON SUNDAY...ANY THUNDERSTORM ACTIVITY LOOKS TO BE CONFINED TO FAR
EASTERN MOHAVE COUNTY BEFORE A STRONGER PUSH OF MONSOON MOISTURE
NUDGES INTO THE AREA ON MONDAY. PRECIPITABLE WATER VALUES BY MONDAY
AFTERNOON RISE INTO THE INCH TO INCH AND A HALF RANGE ACROSS THE
LOWER COLORADO RIVER VALLEY...AND THIS MOISTURE CONTENT ADVECTS
NORTHWARD OVERNIGHT INTO SOUTHERN NEVADA AND EASTERN CALIFORNIA. THE
ARRIVAL OF THIS DEEPER MOISTURE (AIDED BY A RATHER VIGOROUS INVERTED
TROUGH) MAY ALLOW FOR NOCTURNAL CONVECTION MONDAY NIGHT ACROSS AREAS
SOUTH OF INTERSTATE 15. HEAVY RAIN AND STRONG WINDS WILL BE THE
PRIMARY THREATS WITH STORMS MONDAY AND MONDAY NIGHT.
.LONG TERM...TUESDAY THROUGH FRIDAY.
THE LATEST OPERATIONAL MODEL RUNS REMAIN IN GOOD LARGE SCALE
AGREEMENT THIS EVENING FOR THE LONG TERM PERIOD. BOTH THE 00Z RUNS
OF THE GFS AND ECMWF REMAIN CONSISTENT WITH PREVIOUS RUNS REGARDING
THE TIMING AND STRENGTH OF A WELL-DEFINED VORTICITY MAX THAT IS
PROGGED TO BE IN THE PROCESS OF TRAVERSING EASTERN PORTIONS OF THE
CWA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. AS MENTIONED IN THE
PREVIOUS DISCUSSION...THE ECMWF CONTINUES TO PLACE THE CENTER OF THE
FOUR CORNERS HIGH FURTHER WEST THAN THE GFS DOES...LEADING TO A
SLIGHT DELAY IN MOISTURE RETURN AND YIELDING MUCH WARMER
TEMPERATURES TUESDAY ONWARD. DESPITE THE DIFFERENCES IN EXACT
DETAIL...RAISED THUNDERSTORM CHANCES ACROSS THE EASTERN HALF OF THE
FORECAST AREA TUESDAY AND WEDNESDAY TO ACCOUNT FOR THIS FEATURE AND
THE INCREASE IN MOISTURE ACROSS THE AREA. THE MOST FAVORABLE LOCALES
FOR THUNDERSTORMS THROUGH THIS PERIOD APPEARS TO BE MOHAVE COUNTY AT
THIS TIME...THOUGH ACTIVITY COULD POSSIBLY STRETCH AS FAR WEST AS
PORTIONS OF SAN BERNARDINO...INYO...AND NYE COUNTIES.
A WARMUP IN AFTERNOON HIGH TEMPERATURES IS EXPECT FOR THE LATTER
PART OF THE WEEK...AS THE CENTER OF HIGH PRESSURE RETROGRADES
WESTWARD THROUGH THE END OF THE WEEK. WITH NO APPRECIABLE DRY
SOUTHWESTERLY TO WESTERLY FLOW PROGGED OVER THE AREA...THE
LIKELIHOOD OF LOW TO MID-LEVEL MOISTURE GETTING SCOURED OUT IS
LOW...THUS MITIGATING THE AMOUNT OF WARMING THAT WILL OCCUR AS THE
HIGH MOVES OVER THE AREA. FOR THIS REASON...DECIDED TO LEAN AWAY
FROM THE EMWF OUTPUTS THAT CONTINUE TO APPROACH EXCESSIVE HEAT
CRITERIA BY THE WEEKS END. HOWEVER...HAVE BUMPED UP INHERITED TEMPS
FOR THURSDAY THROUGH SATURDAY...INDICATING A GRADUAL WARMUP TO ABOVE
AVERAGE HIGHS BY THE WEEKEND. OTHERWISE...GENERALLY DRY CONDITIONS
ARE EXPECTED.
&&
.AVIATION...FOR MCCARRAN...LIGHTER WINDS EXPECTED TODAY COMPARED TO
YESTERDAY WITH LIGHT AND VARIABLE WINDS FAVORING EASTERLY COMPONENTS
EXPECTED FROM 15Z-21Z BEFORE TRANSITIONING TO A MORE SOUTH-SOUTHWEST
DIRECTION BY 00Z WITH SPEEDS IN THE 9-12KT RANGE WITH GUSTS TO
20KTS. CONFIDENCE IN THE TIMING OF THOSE STRONGER WINDS IS LOW AND
MAY OCCUR AS EARLY AS 21Z OR AS LATE AS 00Z. GUSTY WINDS SHOULD
TAPER OFF AFTER 3Z.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GENERALLY FAIR WEATHER EXPECTED ACROSS THE AREA WITH
AREAS OF SMOKE AND HAZE ESPECIALLY ACROSS INYO COUNTY AND OWENS
VALLEY REGION. AFTERNOON BREEZES OF 10-15KTS WITH GUSTS TO 20KTS ARE
EXPECTED OUT OF THE SOUTH AFTER 21Z AND PERSISTING THROUGH 3Z.
ISOLATED THUNDERSTORMS ARE POSSIBLE NORTH OF LAS VEGAS IN LINCOLN
COUNTY AND ALSO ACROSS FAR NORTHWEST ARIZONA. &&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...PULLIN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1146 PM MDT FRI AUG 21 2015
.AVIATION...
06Z TAF CYCLE
SCATTERED SHOWERS AND A FEW TSTMS WILL CONTINUE ACROSS THE WEST
CENTRAL HIGHLANDS FOR A FEW MORE HOURS AT LEAST. COULD BE A FEW
GUSTS TO 35KTS...AND BRIEF MODERATE RAIN. ANOTHER ROUND OF TSTMS
IS EXPECTED ON SATURDAY...GENERALLY FAVORING THE HIGH TERRAIN AND
SOUTHERN PORTIONS OF THE CWA. CONFIDENCE IS LOW THAT ANY TAF SITE
WILL BE AFFECTED...BUT DID INCLUDE VCTS MENTION AT KROW. STORM
MOTION WILL BE TOWARD THE SE AT 10 TO 20KTS. A STRONG COLD FRONT
WILL PLOW DOWN THE EASTERN PLAINS SATURDAY NIGHT AND THRU THE
CENTRAL MTN CHAIN. BREEZY TO WINDY CONDITIONS WILL FOLLOW THE
FRONT INCLUDING GUSTY CANYON WINDS AT KABQ AND KSAF.
34
&&
.PREV DISCUSSION...944 PM MDT FRI AUG 21 2015...
.UPDATE...
CONVECTION WANING AND SHORT TERM MODELS INDICATE THIS TREND WILL
CONTINUE...THEREFORE TRIMMED BACK EVENING POPS AND REMOVED MENTION
OF STRONG STORMS IN THE FAR EASTERN PLAINS. UPDATED ZFP ALREADY
TRANSMITTED.
&&
.PREV DISCUSSION...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
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
147 AM EDT SAT AUG 22 2015
.SYNOPSIS...
HIGH PRESSURE WILL BRING SEASONABLE AND PLEASANT WEATHER FOR THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE REGION ON MONDAY
WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE WILL BE CENTERED ACROSS OUR REGION OVERNIGHT WITH
FAIR WEATHER AND LIGHT WINDS. THERE MAY BE SOME ISOLATED LAKE
EFFECT CLOUDS NEAR THE IMMEDIATE LAKE SHORES...BUT FOR THE MOST
PART SKIES SHOULD BE CLEAR. THIS SHOULD ALLOW FOR GOOD RADIATIONAL
COOLING AND SOME FOG IN THE SOUTHERN TIER AND NORTH COUNTRY
VALLEYS.
HIGH PRESSURE WILL SLOWLY DRIFT ACROSS NEW ENGLAND SATURDAY WITH
PLENTIFUL SUNSHINE AND LIGHT WINDS. HIGHS IN THE MID 70S ARE
EXPECTED SATURDAY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
HIGH PRESSURE WILL DOMINATE THE FORECAST THIS WEEKEND. A VERY DRY
AIRMASS PER FORECAST SOUNDINGS WILL PROMOTE RAIN-FREE WEATHER AND
PLENTIFUL SUNSHINE ALONG WITH COMFORTABLE TEMPERATURES AND HUMIDITY
LEVELS ACROSS WESTERN AND CENTRAL NEW YORK. HIGHS ON SUNDAY ARE
EXPECTED TO BE NEAR 80. OVERNIGHT LOWS SLIDE BACK INTO THE MID TO
UPPER 50S SATURDAY NIGHT WHILE MILDER OVERNIGHT TEMPS ARE EXPECTED
SUNDAY NIGHT WITH WARM AIR ADVECTION OCCURRING AHEAD OF AN
APPROACHING COLD FRONT.
THE COLD FRONT WILL CROSS WESTERN AND CENTRAL NEW YORK DURING THE
DAY ON MONDAY. VERY LIMITED MOISTURE CONFINED TO BELOW 10KFT WILL
PRECLUDE ANYTHING HIGHER THAN CHANCE POPS AT THIS TIME. WILL GO WITH
SHOWERS IN THE MORNING...TRANSITIONING TO CHANCE THUNDERSTORMS IN
THE AFTERNOON WITH A SECONDARY MID LEVEL TROUGH BRINGING ANOTHER
ROUND OF INSTABILITY DURING THE AFTERNOON.
MOISTURE LINGERS FOLLOWING THE FRONT ON MONDAY NIGHT WITH SKIES
SKIES REMAINING PARTLY TO MOSTLY CLOUDY. COLD ADVECTION WILL DROP
OVERNIGHT TEMPS TO THE 50S...EVEN UPPER 40S INLAND ACROSS THE
SOUTHERN TIER.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
FOLLOWING THE PASSAGE OF THE COLD FRONT...MODELS ARE SHOWING AN
ANOMALOUSLY DEEP 500MB CLOSED LOW SPINNING NORTH OF THE GREAT LAKES
ON TUESDAY THEN LIFTING NORTHEAST INTO NORTHWESTERN QUEBEC BY
THURSDAY MORNING.
AS THE LOW MOVES ACROSS EASTERN ONTARIO...IT WILL SWING A TROUGH
AXIS OVER WESTERN AND NORTH-CENTRAL NEW YORK TUESDAY AND WEDNESDAY.
850MB TEMPERATURES ARE FORECAST TO DROP BACK INTO THE SINGLE DIGITS
/NEAR 2SD BELOW NORMAL/ LEADING TO SOME LAKE EFFECT CLOUDS AND A
CHANCE OF SHOWERS TUESDAY AND TUESDAY NIGHT. THE FOLLOWING MIDLEVEL
TROUGH THEN MAY LEAD TO A CHANCE OF MORE WIDESPREAD SYNOPTIC RAIN
SHOWERS WEDNESDAY AS IT SLIDES ACROSS THE EASTERN GREAT LAKES.
MODELS ARE THEN CONSISTENT WITH BUILDING HIGH PRESSURE BACK OVER THE
FORECAST AREA BY THURSDAY. TEMPERATURES WILL RUN SEASONABLY COOL
THROUGH MUCH OF NEXT WEEK WITH THE COLDER AIR ALOFT. ANOTHER WAVE
THROUGH THE BROAD UPPER TROUGH WILL BRING A COLD FRONT CLOSE TO THE
AREA ON FRIDAY WITH SOME WARMING SOUTHWESTERLY FLOW AND A CHANCE OF
LATE DAY THUNDERSTORMS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN ACROSS THE REGION TODAY AND TONIGHT.
THE ONLY REAL CONCERN FOR AVIATION WILL BE THE POTENTIAL FOR
RADIATION FOG THROUGH THIS MORNING AND AGAIN TONIGHT. THE BEST
CHANCE FOR THIS WILL BE AT JHW WITH SLIGHTLY BETTER THAN A 50-50
CHANCE FOR 2SM OR LESS VSBY TOWARD DAYBREAK THIS MORNING.
ELSEWHERE WILL PROBABLY REMAIN VFR...HOWEVER DID ADD A TEMPO GROUP
FOR LIGHT FOG AT IAG DUE TO A NARROWING TEMP/DEW POINT SPREAD AND
FORECAST LOW MOISTURE IN NAM BUFKIT AND HRRR GUIDANCE.
OTHERWISE...HIGH CONFIDENCE IN VFR CONDITIONS FROM MID-MORNING
TODAY THROUGH THIS EVENING.
OUTLOOK...
SUNDAY...VFR.
MONDAY...MAINLY VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS.
TUESDAY AND WEDNESDAY...VFR.
&&
.MARINE...
HIGH PRESSURE WILL BUILD ACROSS THE AREA THROUGH THE WEEKEND
BRINGING MAINLY LIGHT WINDS AND WAVES TO THE LOWER GREAT LAKES...
WITH VERY SEASONABLE TEMPERATURES AND PLENTIFUL SUNSHINE. A COLD
FRONT WILL APPROACH ON MONDAY... BRINGING THE NEXT CHANCE FOR SOME
STRONGER WINDS/WAVES AND SHOWERS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CHURCH/FRANKLIN
NEAR TERM...APFFEL/CHURCH/FRANKLIN
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...APFFEL
MARINE...CHURCH/FRANKLIN
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1146 PM CDT FRI AUG 21 2015
.UPDATE...
ISSUED AT 1141 PM CDT FRI AUG 21 2015
MAIN IDEAS FROM PREV UPDATE ON TRACK. WARM FRONT FROM SOUTH OF
WINNIPEG TO THE ROLLA ND WITH T-STORMS INCREASING NORTH OF THIS
FRONT OVER MANITOBA. VERY SHORT RANGE CONVECTIVE MODELS DO NOT
HAVE ANY LATE NIGHT CONVECTION IN SE ND/NE SD IN AREA OF LOW LEVEL
JET AND INSTABILITY GRADIENT. STILL LEFT IN THREAT IN THE 09-12Z
AS JUST TOO UNCERTAIN BUT LACK OF DEEP MOISTURE MAY BE INHIBITOR
AS WELL AS MAIN FOCUS OF LOW LEVEL JET IS IN SE MANITOBA AND THE
OTHER MORE SO IN SE SD. EITHER WAY DO EXPECT ISOLD-SCAT SHOWERS
AND T-STORMS TO SPREAD INTO CNTRL ND/DVL REGION LATER TONIGHT INTO
SATURDAY MORNING. COVERAGE OF ACTIVITY DURING THE DAY AHD OF THE
FRONT IS STILL IN QUESTION UNTIL LATE AFTN WHEN TSTMS SHOULD FORM
ALONG THE FRONT EAST OF THE RRV. WRAPAROUND RAINS BEGIN IN DVL
BASIN MID AFTN AND SPREAD EAST.
UPDATE ISSUED AT 947 PM CDT FRI AUG 21 2015
MINOR CHANGES WERE DONE TO THE GRIDS TO INCREASE WINDS A BIT IN SE
ND AS LOW LEVEL JET GOING GOING AND TO INCREASE DEW PTS AS THEY
ARE CLIMBING A BIT HIGHER IN SOME AREAS THAN FCST. OVERALL THOUGH
MONITORING HRRR AND OTHER VERY SHORT RANGE COVECTIVE MODELS STILL
INDICATES ABOUT A 40 KT LOW LEVEL JET INTO ERN ND OVERNIGHT...AND
RAP MODEL ESPECIALLY HAS ONE AREA OF ENHANCED INSTABILITY MOVING
INTO SE ND TO THE CENTRAL RRV 09Z-10Z PERIOD. BUT BEST MOISTURE
SATURATION IS MORE NORTH OF THE WARM FRONT WHICH IS LOCATED NR THE
INTL BORDER. THUS HRRR HAS BEST COVERAGE OF ANY STORMS MORE TOWARD
WINNIPEG. ANOTHER PIECE OF A STRONGER LOW LEVEL JET OVER NEBRASKA
AND SOME MODELS BREAK OUT TSTMS IN SCNTRL SD WITH THIS. SO OVERALL
NOT SEEING CLEAR CUT SIGNS OF LATE NIGHT CONVECTION IN ERN ND/RRV
BUT STILL WAY TO MANY VARIABLES TO REMOVE. THUS CONTINUING WITH
LOW POPS.
UPDATE ISSUED AT 638 PM CDT FRI AUG 21 2015
THICKER HIGH CLOUDS REMAIN OVER THE NRN RRV INTO NW MN WITH CLEAR
SKIES DVL-FARGO SOUTHWARD...THOUGH SOME HIGH LEVEL SMOKE. BETTER
MID-HIGH LEVEL MOISTURE IN A BAND FROM CNTRL MONTANA ACROSS NW ND
INTO MANITOBA. IN THIS AREA IS WHERE THE THREAT FOR A FEW SHOWERS
WILL BE THIS EVENING...WHICH IS WEST AND NORTH OF OUR AREA. MAIN
THREAT WILL BE LATER TONIGHT TO SEE IF INCREASING 850 MB JET
COMBINED WITH 850 MOISTURE AND INSTABILITY INCREASE CAN BE ENOUGH
TO GENERATE SOME STORMS IN CNTRL ND OR INTO THE DVL REGION. HRRR
MODEL STILL SHOWING THAT POTENTIAL. SO FAR FCST OK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 25
THE MAIN CHALLENGE WILL BE SEVERE POTENTIAL ON SATURDAY...RAIN
THEN WIND. MODELS HAVE COME INTO PRETTY GOOD AGREEMENT WITH THIS
SYSTEM...WITH THE GFS/ECMWF VERY SIMILAR WITH ALL FIELDS.
FOR TONIGHT...A LLJ WILL INCREASE TO ABOUT 30-40KT INTO NE SD
AROUND 6-9Z. THERE WILL ALSO BE A FAIRLY RAPID INCREASE TO MID
LEVEL MOISTURE AND INSTABILITY...WITH SHOWALTERS FALLING INTO THE
-6 TO -8C RANGE ALONG WITH 850MB CAPE OF AROUND 2000 J/KG.
THEREFORE...WILL MENTION LOW POPS IN THE SOUTH AND LOW CHANCE POPS
IN THE NW FOR ELEVATED SHOWERS AND STORMS LATE TONIGHT.
ON SATURDAY...A STRONG COLD FRONT AND SFC LOW WILL MOVE TO NEAR
THE RED RIVER VALLEY IN THE 18-21Z TIMEFRAME...THEN RACE INTO THE
EASTERN ZONES AROUND 00-03Z. THERE WILL BE STRONG INSTABILITY
PARAMETERS WITH MLCAPE OF NEAR 3000 J/KG IF WE CAN GET SFC
DEWPOINTS INTO THE MID/UPPER 60S. THE STRONGER DEEP LAYERED SHEAR
DOES LAG THE WARM SECTOR SOME...BUT GIVEN STRONG WAVE/FORCING AND
SFC CONVERGENCE NEAR THE FRONT...EXPECT SOME SEVERE STORMS. THE
BEST COVERAGE FOR SEVERE STORMS SHOULD OCCUR EAST OF THE VALLEY.
IT IS INTERESTING TO NOTE THAT THE NAM HAS MORE OF A CLOSED SFC
LOW NEAR KGFK AROUND 21Z...MOVING INTO NW MN THEREAFTER. SHOULD
THIS OCCUR...THEN THE TORNADO THREAT WOULD INCREASE NEAR AND NORTH
OF THIS LOW...SO SOMETHING TO WATCH. TEMPS WILL LIKELY REMAIN IN
THE 70S FOR THE MOST PART GIVEN CLOUDS AND THE COLD FRONT.
ON SAT NIGHT...WINDS WILL INCREASE AND EXPECT A DEFORMATION
SHOWER/RAIN BAND TO DEVELOP IN THE NORTH OVERNIGHT. SOME AREAS
COULD GET AN INCH OR MORE OF RAIN NEAR HEAVIER PERSISTENT SHOWERS
IN THE NORTH.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 250 PM CDT FRI AUG 21 2015
ON SUNDAY...IT WILL BE COOL...WINDY WITH MAINLY MORNING SHOWERS
IN THE NORTH AND EAST. TEMPS WILL BE WELL BELOW NORMAL ALONG WITH
STRONG WINDS. THERE WILL BE ABOUT 45-50KT TO MIX FROM THE NW...SO
WE MAY NEED A WINDY ADVISORY HEADLINE FOR THE VALLEY AND POINTS
WEST...BUT STILL TIME TO IRON OUT THESE DETAILS OUT.
FOR MONDAY...IT WILL BE DRY AND COOL WITH TEMPS BELOW NORMAL.
FOR MONDAY NIGHT THROUGH THURSDAY...MODELS WERE IN GOOD
AGREEMENT ON POSITIONING OF UPPER AIR AND SFC FEATURES THIS RUN.
SFC HIGH PRESSURE IS FORECAST TO BE OVER THE AREA WITH THE AXIS
CENTERED OVER THE RED RIVER VALLEY...AND SLOWLY DRIFT SE THRU THE
PERIOD. OTHERWISE...THE UPPER RIDGE OVER THE INTERMOUNTAIN WEST
CONTINUES TO BUILD AND SHIFT E THRU THE PERIOD. THIS IS EXPECTED
TO BRING A RETURN TO WARMER TEMPERATURES...WITH MAINLY 80S WEST
AND UPPER 70S EAST. A FEW SHORT WAVES WILL PROPAGATE THRU THE
FLOW...BRINGING A FEW CHANCES FOR PCPN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1141 PM CDT FRI AUG 21 2015
MADE FEW CHANGES FROM 00Z TAF SUITE. KEPT TEMP GROUPS SHOWING BEST
TIME PERIOD FOR ANY CONVECTION IN THE RRV AND NW MN TAF SITES SAT
AFTN. GUSTY SOUTH-SOUTHEAST WINDS AT TIMES...ESP FARGO...THEN
INCREASING NORTHWEST WINDS DVL REGION SAT MID AFTN SPREADING EAST
SAT NIGHT. EXPECT MVFR CIGS AND MAYBE IFR CIGS TO SPREAD INTO NE
ND/RRV SAT NIGHT WITH WRAPAROUND RAIN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...HOPKINS/DK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
204 AM EDT SAT AUG 22 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 TODAY/...
AS OF 2 AM...SEEING A FEW SMALL/LIGHT SHOWERS DEVELOP NEAR THE BLUE
RIDGE...LIKELY IN RESPONSE TO A LOW LEVEL EASTERLY FLOW...AS WELL AS
AN UPPER SPEED MAX THAT IS MOVING ACROSS THE AREA ATTM. INTRODUCED
SMALL CHANCES FOR SHOWERS OVERNIGHT ACROSS ROUGHLY THE EASTERN HALF
OF THE AREA...MAINLY AS A NOD TO THE MESOSCALE MODELS AS MUCH AS
ANYTHING (ALTHOUGH THESE APPEAR TO BE SIGNIFICANTLY OVERDOING THE
PRECIP). MIN TEMPS SHOULD AVERAGE ABOUT A CATEGORY ABOVE CLIMO.
AS OF 10:25 PM FRIDAY...A FEW LIGHT SHOWERS HAVE DEVELOPED OVER
WESTERN NORTH CAROLINA WHICH MAY REFLECT SOME WEAK FORCING IN
ADVANCE OF A WEAK VORTICITY MAX THAT IS MOVING TOWARDS THE AREA.
SOME WIDELY SCATTERED RAIN SHOWERS WILL REMAIN POSSIBLE THROUGH THE
NIGHT AND INTO THE MORNING HOURS.
AS OF 745 PM FRIDAY...AREA IS ENTIRELY CLEAR OF ANY RADAR ECHOES AT
THE MOMENT WITH LIGHT AND VARIABLE WINDS AND PARTLY CLOUD SKIES.
CONVECTIVE ACTIVITY INDICATED BY CAMS WAS OVERDONE BY THE MODELS.
CURRENT EXPECTATIONS ARE FOR NO PRECIP THROUGH 5Z AT LEAST. AFTER
5Z...A WEAK SHORTWAVE EMBEDDED IN THE SOUTHWESTERLY FLOW ALOFT MAY
KICK-OFF A FEW WIDELY SCATTERED AND WEAK SHOWERS...ESPECIALLY IN
EASTERN PARTS OF THE CWA WHICH HAS SLIGHTLY BETTER MOISTURE. A
BETTER CHANCE FOR PRECIPITATION WILL BE SATURDAY AFTERNOON AS THE
MAIN SHORTWAVE APPROACHES FROM THE WEST.
AS OF 510 PM 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 /TONIGHT 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 /06Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...SMALL/ISOLATED SHOWERS ARE EXPECTED TO
CONTINUE DEVELOPING THROUGH MUCH OF THE EARLY MORNING...MAINLY NEAR
KHKY AND PERHAPS KCLT. HOWEVER...ONLY FELT THE NEED TO INCLUDE A
VCSH AT KHKY...AS PART OF THE IMPETUS FOR THESE SHOWERS WILL BE A
MOIST EASTERLY LOW LEVEL UPSLOPE FLOW. SPEAKING OF WHICH...THIS
AND ATTENDANT POTENTIAL FOR LOW CIGS WILL BE THE PRIMARY CONCERN
FOR THIS PERIOD. THERE IS NO REAL DEFINITIVE CONSENSUS IN GUIDANCE
SOURCES AS TO HOW LOW CIGS WILL GET LATER THIS MORNING...BUT FELT
STRONGLY ENOUGH ABOUT THE POTENTIAL TO INCLUDE MVFR CIGS AT MOST
TERMINALS BY AROUND DAYBREAK. ALSO CONCERNED ABOUT THE FOG POTENTIAL
NEAR KAVL...BUT AS USUAL...THIS IS NOT CLEAR CUT...ESP IN LIGHT OF
AN AREA OF HIGH CLOUDS THAT IS EXPECTED TO OVERSPREAD THE NC MTNS BY
AROUND 09Z. THEREFORE OPTED FOR CATEGORICAL MVFR CONDITIONS...WITH
TEMPOS FOR LOW MVFR CONDITIONS THERE TOWARD DAYBREAK.
OTHERWISE...FORECASTING THE POTENTIAL FOR DIURNAL CONVECTION THIS
AFTERNOON IS EVERY BIT AS PROBLEMATIC AS IT WAS YESTERDAY...WHEN
GUIDANCE DEPICTED A STRONG CONSENSUS OF SCT/NUMEROUS CONVECTION
ACROSS UPSTATE SC AND THE NC MTNS... YET VIRTUALLY NOTHING
OCCURRED. THE SAME HINDRANCES WILL EXIST TODAY...NAMELY IN THE FORM
OF MORNING CLOUD COVER THAT WILL LIMIT INSTABILITY. NEVERTHELESS...
WITH THE APPROACH OF AN UPPER AIR DISTURBANCE ANTICIPATED THIS
AFTERNOON...OPTED TO INCLUDE A VCSH AT KAVL. THE OTHER TERMINALS
WILL RECEIVE CLOSER SCRUTINY FOR CONVECTIVE POTENTIAL FOR THE 12Z
TAFS...ALTHOUGH IT DOES APPEAR THAT KCLT WILL MOST LIKELY BE FREE
OF CONVECTION THIS PM.
OUTLOOK...DIURNAL CONVECTIVE CHANCES AND POTENTIAL FOR MORNING
FOG/STRATUS...ESP IN THE MTN VALLEYS WILL PERSIST INTO MONDAY. A
COLD FRONT IS EXPECTED TO BRING DRIER AIR INTO THE AREA BY
TUE...LIKELY BRINGING AN END TO CONVECTIVE AND MORNING RESTRICTION
CHANCES FOR AT LEAST A COUPLE OF DAYS.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 92% MED 72% HIGH 100% HIGH 100%
KGSP HIGH 93% MED 78% HIGH 95% HIGH 100%
KAVL LOW 55% MED 74% HIGH 81% HIGH 80%
KHKY HIGH 94% MED 66% HIGH 87% HIGH 100%
KGMU HIGH 93% MED 75% HIGH 97% HIGH 100%
KAND HIGH 81% MED 68% 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...JDL/WIMBERLEY/WJM
SHORT TERM...CDG
LONG TERM...LEV
AVIATION...JDL
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
119 AM CDT SAT AUG 22 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
MOSTLY HIGH CLOUDS ACROSS THE CWA LATE TONIGHT. RADAR IMAGES
INDICATED ISOLATED SHOWERS ACROSS THE COASTAL SECTIONS. CEILINGS
WERE NEAR 3400FT AT KPIL. VISIBILITIES WERE NEAR 5SM WITH LIGHT
RAIN AND FOG AT KPIL. EXPECT VFR CONDITIONS TO PREVAIL THE REST OF
TONIGHT INTO SAT MORNING EVEN AS LOW TO MID LEVEL MOISTURE REMAINS
RELATIVELY HIGH ACROSS THE AREA. A WEAK INVERTED 500MB TROUGH
ACROSS NORTHEAST MEXICO MAY ALLOW ISOLATED SHOWERS TO DEVELOP
ACROSS PORTIONS OF THE RIO GRANDE VALLEY SAT MORNING.
&&
.PREV DISCUSSION... /ISSUED 624 PM CDT FRI AUG 21 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...A STABLE ATMOSPHERE TO PROVIDE A VFR SKY MUCH OF THE
NIGHT FOR MOST OF THE REGION. SOME MVFR CIGS TO DEVELOP OVER THE
CENTRAL REGIONS OF DEEP SOUTH TEXAS AFTER MIDNIGHT WITH KMFE
POSSIBLY BEING IMPACTED FOR A FEW HOURS. HIGH RESOLUTION MODELS
SUGGEST A MODERATE CHANCE OF MVFR A FEW HOURS EITHER SIDE OF
SUNRISE ALONG THE HIGHWAY 69C/281 CORRIDOR. THERE IS LOWER
PROBABILITY AND LOWER CONFIDENCE OF MVFR CIGS DEVELOPING EAST IN
THE VICINITY OF KHRL AND KBRO. VFR TO PREVAIL SATURDAY. LIGHT
SOUTHEAST WINDS TO INCREASE SATURDAY AFTERNOON WITH SOME GUSTS
BETWEEN 20-25KNOTS.
PREV DISCUSSION... /ISSUED 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 SKEPTICAL 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.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
61/52
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1153 PM CDT FRI AUG 21 2015
.AVIATION...
/06Z TAFS/
Latest model data indicate stratus still likely for much of West
Central Texas tonight. Based on the latest satellite imagery,
stratus onset for Junction and Brady may be an hour earlier than
previous thinking. Thus, slight timing adjustments for those two
terminals appear best this cycle. Return to VFR still looks
likely around noon tomorrow.
&&
.PREV DISCUSSION... /ISSUED 1044 PM CDT FRI AUG 21 2015/
UPDATE...
Made some minor updates to decrease pops down to 20 percent
over Haskell and Throckmorton counties and extend 20-30 pops
slightly farther into Sterling and Irion counties for tonight.
Latest HRRR models indicates storms near Lamesa may move into
extreme NW portions of the Concho Valley before dissipating.
PREV DISCUSSION... /ISSUED 620 PM CDT FRI AUG 21 2015/
AVIATION...
/00Z TAFS/
Look for stratus to develop across much of West Central Texas
overnight. Models indicate MVFR ceilings are likely, mainly south
of Interstate 20, by sunrise tomorrow morning. Conditions should
return to VFR around noon tomorrow.
PREV DISCUSSION... /ISSUED 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.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
913 AM MDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 913 AM MDT SAT AUG 22 2015
COLD FRONT IS A LITTLE AHEAD OF SCHEDULE AND ALREADY REACHING
THE NORTHERN BORDER AREA. THERE IS AN UNSEASONABLY STRONG PRESSURE
SURGE BEHIND THIS FRONT...BUT AT THE SAME TIME FRONT WILL BE
RUNNING INTO BETTER MIXING AND DAYTIME HEATING WHICH COULD ALLOW
FRONT TO WASH OUT A BIT. AS A RESULT...CHALLENGING WIND FORECAST
BETWEEN WEST/NORTHWEST OVER THE MOUNTAINS AND NORTH/NORTHEAST
ACROSS THE PLAINS. HRRR AND RAP MODELS APPEAR OVER MIXED AT THIS
POINT WHICH IS A TYPICAL BIAS...AND BELIEVE BASED ON REAL DATA
UPSTREAM THAT THE FRONT WILL HAVE ENOUGH STRENGTH TO BACK INTO/UP
AGAINST THE FRONT RANGE FOOTHILLS. MADE A FEW ADJUSTMENTS TO
TEMPS/DIURNAL TRENDS AND WINDS ON THE PLAINS BASED ON THESE
EXPECTATIONS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 300 AM MDT SAT AUG 22 2015
STRONG UPPER LEVEL TROF AND ASSOCIATED COLD FRONT WILL SWEEP
ACROSS THE NORTHERN HIGH PLAINS AND ROCKY MOUNTAIN REGION THIS
AFTERNOON. CURRENT COLD FRONTAL LOCATION IS ACROSS NORTHERN
WYOMING AND EXPECTED INTO FAR NORTHERN COLORADO BORDER AREAS BY
MID MORNING AND THEN INTO DENVER AREA AND POINTS SOUTH THIS
AFTERNOON. DECENT PRESSURE RISES WITH THIS FRONT AND WIND GUSTS IN
THE 25-40KT RANGE. WINDS WON`T BE QUITE THAT STRONG IN COLORADO
BUT CERTAINLY IN THE 15-30KT RANGE LOOKS REASONABLE AS BEST
PRESSURE RISES WILL SHIFT INTO NEBRASKA. THE BRUNT OF THE
MOISTURE AND LIFT WITH THIS TROF WILL REMAIN WELL NORTH AND EAST
OF COLORADO BUT THERE COULD BE SOME SHOWERS ACROSS THE PALMER
DIVIDE AND SOUTHERN PORTIONS OF CWA. BEHIND THE COLD FRONT...DRY
AND STABLE AIRMASS WILL MOVE IN WITH CLEARING SKIES TONIGHT AS
TEMPERATURES DROP INTO 40S AND LOWER 50S ACROSS THE PLAINS.
WITH THE UPPER TROF TRAJECTORY COULD ALSO CONTINUE TO SEE
SMOKE/HAZY CONDITIONS FROM FIRES ACROSS THE PACIFIC NORTHWEST.
SOME OBSERVATIONS SITES IN WYOMING AND SOUTH DAKOTA AND OBSERVING
SMOKE AND HAZE. CURRENT WEATHER GRIDS ALREADY HAVE THIS ADDRESSED
SO NO CHANGES NEEDED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM MDT SAT AUG 22 2015
AN UNSEASONABLY STRONG UPPER TROUGH MOVING ALONG THE U.S./CANADIAN
BORDER SWEEPS OUT OVER THE NORTHERN GREAT PLAINS ON SUNDAY AS THE
FLATTENED UPPER RIDGE OVER THE 4-CORNERS REGION REGAINS SOME
AMPLITUDE. THIS KEEPS THE FORECAST AREA UNDER THE INFLUENCE OF A
GENERALLY DRY NORTHWEST FLOW...AND WITH THIS FLOW REACHING UP OVER
THE PACIFIC NORTHWEST...WE COULD CONTINUE TO SEE HAZY SKIES AROUND
HERE BUT PERHAPS LESS OPAQUE AS THE LOW-LEVEL FLOW IS FORECAST TO
SHIFT TO A LESS SMOKEY S-SWLY COMPONENT IN THE AFTERNOON. SUCH A
FLOW WILL AID IN WARMING THE POST-FRONTAL AIRMASS PARTICULARLY ON
THE PALMER DIVIDE AND SOUTHERN PORTIONS OF THE I-25 URBAN CORRIDOR
INCLUDING THE GREATER DENVER METRO AREA WHERE HIGH TEMPERATURES WILL
BE NEAR AVERAGE FOR THE DATE. FARTHER OUT ON THE PLAINS SEE LITTLE
CHANGE IN TEMPERATURE FROM THE DAY BEFORE WITH HIGHS SEVERAL DEGS
BELOW AVERAGE. FROM AFTERNOON INTO THE OVERNIGHT HOURS MODELS SHOW
FURTHER STRENGTHENING OF THE UPPER RIDGE AND AS BUILDS NORTHWARD SO
WILL MID/HIGH-LEVEL MOISTURE. COULD SEE A FEW LIGHT RAIN SHOWERS/T-
STORMS PRODUCING GUSTY WINDS OVER THE HIGH TERRAIN ACRS SWRN
SECTIONS OF THE CWA BY EVENING. OTHERWISE DRY CONDITIONS WILL
PREVAIL.
ON MONDAY...FURTHER AMPLIFICATION OF THE UPPER RIDGE AND A SLIGHT
EASTWARD SHIFT SHOULD BEGIN TO DIVERT MORE OF THE SMOKE FROM PAC
NORTHWEST WILDFIRES AWAY FROM THE FRONT RANGE. HOWEVER IT MAY BE
LESS APPARENT AS SKIES WILL LIKELY CONTAIN MORE CLOUDS AS
SUBTROPICAL MOISTURE FLOWS UP FROM THE 4-CORNERS REGION. NOT LOOKING
FOR A BUNCH OF CLOUDS AND THE CHANCE FOR MEASURABLE PRECIP SHOULD
REMAIN LOW ESPLY EAST OF THE MTNS. WARMING ALOFT SHOULD CAP T-STORM
DEVELOPMENT ON THE PLAINS. THIS SAME WARMING ALOFT WILL BE REFLECTED
AT THE SURFACE BY HIGH TEMPERATURES 4-7 DEG F WARMER THAN THE DAY
BEFORE. THE BIGGEST CHANGE IN TEMPERATURE WILL OCCUR ACRS THE NERN
CORNER OF THE CWA WHERE CLOUD COVER LESS EVIDENT.
FOR TUESDAY AND WEDNESDAY...MODELS SHOW THE UPPER RIDGE CONTINUING
TO MIGRATE EAST WHICH OPENS UP THE REGION TO INCREASINGLY MOIST SWLY
FLOW. AREAS EAST OF THE MTNS SHOULD NOT SEE MUCH IMPACT FROM THIS
INFLUX OF MOISTURE OTHER THAN MORE AFTERNOON/EVENING CLOUD COVER AND
PERHAPS A SLIGHTLY BETTER CHANCE OF LATE DAY T-STORMS MAINLY ALONG
THE FRONT RANGE. MTN AREAS WILL HAVE A BETTER CHANCE FOR T-STORMS
DURING THE PERIOD ESPLY WEDNESDAY WHEN MODELS SHOW A WEAK UPPER AIR
DISTURBANCE PASSING OVER THE AREA. WILL STICK WITH PRECIP CHANCES IN
THE 30-50 PCT RANGE IN THE HIGH COUNTRY WITH 10-20 PCT AT LOWER
ELEVATIONS. TEMPERATURES BOTH DAYS LITTLE CHANGED FROM MONDAY AND
STILL SLIGHTLY ABOVE AVERAGE FOR THE DATE.
THURSDAY AND FRIDAY...MEDIUM RANGE MODELS AGREE IN RETROGRADING THE
UPPER RIDGE AS THE UPPER AIR DISTURBANCE SLOWLY DROPS SEWRD OVER
NERN COLORADO DURING THE DAY THURSDAY. LEADING THE DISTURBANCE WILL
BE A WEAK COLD FRONT WHICH FIRST USHER DRY AIR DOWN FROM WY ON NWLY
WINDS THEN SHIFTS TO AN UPSLOPE FLOW WHICH MAY STIMULATE T-STORM
FORMATION OVER AND ALONG THE FRONT RANGE BY THE AFTERNOON AS THE
UPPER AIR DISTURBANCE PASSES BY. BY FRIDAY COULD SEE THE UPPER RIDGE
BUILDING BACK OVER THE STATE AND AS IT DOES RETURNING THE AREA TO
NWLY FLOW ALOFT. THIS COULD AGAIN BLOW IN MORE SMOKE FROM THE
PACIFIC NW WILDFIRES. OTHERWISE FRIDAY SHOULD BE THE DRIER DAY...
WITH TEMPERATURES BOTH DAYS NEAR AVERAGE.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 913 AM MDT SAT AUG 22 2015
EXPECT A FRONT OR AT LEAST AN INITIAL SURGE TO REACH KDEN BY 18Z
AND KBJC/KAPA BY 19Z-20Z. THIS SHOULD TURN WINDS MORE NORTHERLY
AND INCREASE GUSTS TO 25 KTS WITH A FEW GUSTS TO 30 KNOTS FOR A
COUPLE HOURS BY EARLY/MID AFTERNOON. ISOLATED THUNDERSTORMS ARE
EXPECTED TO BE CONFINED TO POINTS JUST SOUTH OF THE DENVER METRO
AREA AND FRONT RANGE AIRPORTS...MAINLY OVER THE PALMER DIVIDE AREA
22Z-02Z. SOME SMOKE/HAZE REPORTED BEHIND THE FRONT THIS MORNING IN
WYOMING SO COULD SEE A FEW HOURS OF VISIBILITIES DROPPING TO 4-5SM
LATER THIS AFTERNOON/EVENING. WILL CONTINUE TO MONITOR
PROGRESSION OF SMOKE.
&&
.FIRE WEATHER...
ISSUED AT 913 AM MDT SAT AUG 22 2015
THERE WILL STILL BE A NARROW CORRIDOR OF VERY WARM AND DRY AIR
LOCATED OVER THE MOUNTAINS AND HIGH VALLEYS OF NORTH CENTRAL
COLORADO TODAY. UPSTREAM RIVERTON AND GRAND JUNCTION SOUNDINGS
SHOWED A DRY AIRMASS AND SUFFICIENT WINDS ALOFT. DAYTIME HEATING
AND MIXING WILL LEAD TO INCREASING WINDS AND RED FLAG CONDITIONS
IN ZONES 211...213...217...AND 218 THROUGH MUCH OF THE AFTERNOON
WHERE FUELS ARE DRIEST. HAVE ISSUED A RED FLAG WARNING FOR THOSE
LOCATIONS...BUT CONDITIONS WILL IMPROVE BY 6 TO 7 PM AT THE
LATEST. COLD FRONT MOVING ACROSS THE PLAINS AND SHOULD BACK INTO
THE LOWER FOOTHILLS THROUGH THE AFTERNOON. ZONES 215 AND 216
MARGINAL FOR RED FLAG CONDITIONS BUT STILL SOME THREAT THERE BUT
MAINLY OVER EXPOSED HIGHER RIDGES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ211-213-217-
218.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...ENTREKIN
LONG TERM...BAKER
AVIATION...BARJENBRUCH
FIRE WEATHER...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
1036 AM EDT SAT AUG 22 2015
.UPDATE...
NO MAJOR CHANGES FOR THIS UPDATE. TWEAKED POPS FOR THIS MORNING TO
BETTER REFLECT WHAT IS CURRENT SHOWING ON RADAR. THE HRRR IS
STILL SHOWING SOME THUNDERSTORM ACTIVITY THIS AFTERNOON. THIS
MORNINGS SOUNDING DOES SHOW WARM TEMPERATURE OF -4.9C AT 500MB.
ALSO, THE FREEZING LEVEL IS OVER 16000FT. THE NCAPE IS .14,
INDICATING STORMS LIFE MAY BE A COMBINATION OF SOME PULSE TYPE
STORMS, AND A FEW CELLS THAT HAVE A SOMEWHAT LONGER LIFE SPAN. THE
PWATS ARE JUST OVER 2 INCHES, WHICH MEANS, TYPICAL HEAVY RAIN.
HOWEVER, THE STORM MOTION WILL FAIRLY SLOW, BEING LESS THAN 10KTS.
HOWEVER, MOST OF THE ACTIVITY SHOULD BE IN THE INTERIOR, SO ANY
URBAN FLOODING, EVEN MINOR, LOOKS TO BE AT A VERY LOW RISK. BUT,
IF STORMS DO DEVELOP A LITTLE FURTHER EAST, IT COULD LEAD TO
PONDING OF WATER ON ROADWAYS AND POOR DRAINAGE AREAS. OTHERWISE,
LOOKING AT TYPICAL GARDEN VARIETY THUNDERSTORMS, WITH AN ISOLATED
STRONG STORM POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 752 AM EDT SAT AUG 22 2015/
AVIATION...
HIGH PRESSURE, TO THE NORTHWEST, WILL KEEP THE WIND OUT OF THE NORTH
TO NORTHEAST TODAY. THE ATLANTIC SEA BREEZE WILL DEVELOP IN THE
EARLY AFTERNOON. THIS WILL HELP TO CAUSE THUNDERSTORMS TO DEVELOP.
MOST OF THE STORMS SHOULD BE WEST OF THE TAF SITES, ALTHOUGH THERE
IS STILL A CHANCE OVER THE AIRPORTS,, SO HAVE A VCTS IN THE TAFS
FOR THE AFTERNOON AND EVENING HOURS. VFR CONDITIONS ARE EXPECTED
THROUGH THE TAF PERIOD, WITH BRIEF IFR UNDER HEAVY RAIN AND
THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 325 AM EDT SAT AUG 22 2015/
DISCUSSION...
RIDGE OF HIGH PRESSURE OVER THE EASTERN GULF AND FLORIDA WILL
DOMINATE THE REGION THROUGH SUNDAY. THIS WILL FOCUS AFTERNOON
CONVECTION ACROSS THE INTERIOR AND GULF COAST. ISOLATED MORNING
TSTORMS ARE POSSIBLE ACROSS THE EAST COAST METRO. THE MAIN TSTORM
IMPACTS WILL BE LIGHTNING STRIKES AND HEAVY DOWNPOURS.
WINDS THIS MORNING ARE OFFSHORE OUT OF THE NW AND LIGHT ACROSS THE
EAST COAST METRO AND NEAR SHORE ATLANTIC WATERS. AS CUMULUS
DEVELOPS THIS MORNING...THIS OFFSHORE WIND FLOW CONVERGING ONTO
THE SYNOPTIC ENE WIND FLOW...COULD RESULT IN A FEW WATERSPOUTS
FORMING OVER THE ATLANTIC AND BISCAYNE BAY THIS MORNING.
INTERESTINGLY...NRL/NAVY AEROSOL MODEL SHOWS THAT SKIES COULD
BECOME SOMEWHAT HAZY ACROSS SOUTH FL TODAY AND INTO EARLY NEXT
WEEK...BUT NOT FROM SAHARAN DUST, RATHER SULFATE/POLLUTANTS FROM
THE MAINLAND/DEEP SOUTH SPREADING SOUTH DOWN THE PENINSULA.
THE AFOREMENTIONED RIDGE WILL BE REPLACED BY A TROUGH DIGGING
INTO THE EASTERN SEABOARD EARLY-MID NEXT WEEK. THIS WILL RESULT
IN A MORE SW STEERING WIND ALBEIT RATHER LIGHT. FOLLOWED A CLIMO
PATTERN OF DIURNAL CONVECTION EACH DAY WITH FOCUS OVER THE
INTERIOR EACH DAY. GFS IS MORE AMPLIFIED LATE NEXT WEEK WHILE
ECMWF NUDGES IN A RIDGE...SO FLOW PATTERN IS MORE UNCERTAIN THEN.
HURRICANE DANNY IS FORECAST TO CONTINUE TO WEAKEN AS IT HAS DRY
AIR, WIND SHEAR, AND POSSIBLY LAND INTERACTION AHEAD OF IT. GLOBAL
MODELS DEGENERATE DANNY INTO AN OPEN WAVE. WE WILL CONTINUE TO
MONITOR DANNY`S PROGRESS, BUT FOR NOW A CLIMO FORECAST NEXT WEEK
IS LOOKING PRUDENT. /GREGORIA
MARINE...
A NORTHEASTERLY WIND WILL PREVAIL INTO EARLY NEXT WEEK WITH SPEEDS
AVERAGING 10 KT OR LESS. SEAS WILL BUILD SLIGHTLY...BUT STILL BE
LESS THAN 4 FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 93 80 92 78 / 20 20 30 10
FORT LAUDERDALE 91 80 91 80 / 20 20 40 20
MIAMI 93 80 93 79 / 20 20 50 30
NAPLES 91 79 92 77 / 40 40 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...13/SI
LONG TERM....60/BD
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 1045 AM CDT SAT AUG 22 2015
WILL NEED TO UPDATE THE FORECAST TO INCREASE CHANCES OF SHOWERS
AND POSSIBLE THUNDERSTORMS IN OUR SW COUNTIES FROM SPRINGFIELD
LATE THIS MORNING AND EARLY AFTERNOON. ALSO INCREASED CLOUD COVER
INTO EARLY AFTERNOON ESPECIALLY SW OF I-74. SHOWERS WERE AS FAR NE
AS SCOTT AND MORGAN COUNTIES AT 1040 AM WITH THUNDERSTORMS AROUND
ST LOUIS. THIS CONVECTION WAS DRIFTING NE AND WEAKENING AND SHOULD
CONTINUE TO WEAKEN NEXT FEW HOURS AS IT MOVES ACROSS OUR SW THIRD
OF CWA. MOST OF THIS CONVECTION SHOULD DISSIPATE BY MID AFTERNOON
WITH CLOUDS BREAK UP DURING THE MID/LATE AFTERNOON. HIGHS IN THE
LOW TO MID 80S THIS AFTERNOON.
&&
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
MOST OF OUR AREA STILL UNDER THE INFLUENCE OF HIGH PRESSURE WHICH
HAS SHIFTED INTO SOUTHEAST OHIO EARLY THIS MORNING. MEANWHILE TO
OUR SOUTHWEST...A WEAK SHORTWAVE WAS TRACKING EAST ACROSS WESTERN
MISSOURI WITH SHORT TERM MODELS CONTINUING TO SUGGEST SHOWERS AND
STORMS WILL EXPAND IN COVERAGE EARLY THIS MORNING AS THE UPPER LEVEL
WAVE TRACKS EAST. HOWEVER...BOTH THE RAP-13 AND HRRR MODELS HAVE
OVERDONE THE PRECIP ACROSS SOUTHWEST MISSOURI EARLY THIS
MORNING...ESPECIALLY COMPARED TO WHAT IS ACTUALLY OCCURRING NOW.
FORECAST SOUNDINGS INDICATE A BIT MORE CLOUD COVER OVER OUR WEST AND
SOUTHWEST COUNTIES AHEAD OF THE AFOREMENTIONED WAVE TODAY WITH SOME
850 MB MOISTURE CONVERGENCE SEEN ON THE MODELS THIS MORNING OVER
PARTS OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...ESPECIALLY LATE
THIS MORNING...TOWARDS 18Z. HAVE ADDED SOME SLIGHT CHANCE POPS OVER
FAR WEST AND SOUTHWEST IL FOR THIS MORNING INTO EARLY THIS AFTERNOON
JUST AHEAD OF THE WEAKENING UPPER WAVE. FURTHER EAST AND NORTH...
LESS CLOUD COVER SHOULD ALLOW AFTERNOON TEMPS TO RISE INTO THE LOW
TO MID 80S BASED OFF THE RAP SOUNDINGS.
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
RAIN CHANCES INCREASING OVERNIGHT AND INTO TOMORROW AS A COLD FRONT
APPROACHES THE FORECAST AREA. PASSAGE OF THE COLD FRONT EXPECTED IN
THE EARLY MORNING HOURS THROUGH MIDDAY. WITH A LACK OF DIURNAL
HEATING IN THE AIRMASS OUT AHEAD OF THE BOUNDARY, HAVE PULLED THE
MAX TEMPS DOWN A COUPLE DEGREES. SOUTHEAST MAY REMAIN SOMEWHAT
WARMER FOR SUNDAYS HIGHS AND ILX WILL LIKELY HAVE QUITE A GRADIENT
OVER THE REGION. WITH THE GENERAL EARLINESS OF THE SYSTEM, LITTLE TO
NO SEVERE WEATHER IS EXPECTED. BEHIND THE COLD FRONT, HIGH PRESSURE
BUILDS BACK IN AT THE SURFACE. IN THE COOLER AIRMASS, THE TEMPS WILL
REMAIN SLIGHTLY BELOW NORMAL THROUGH MIDWEEK...BUT TRENDING WARMER.
THE WARM TREND WILL BE ENHANCED EVEN FURTHER AS THE HIGH PRESSURE
RIDGE AXIS SLIPS OFF TO THE EAST AND THE SFC WINDS BECOME MORE
SOUTHERLY AHEAD OF THE NEXT FRONT. AT THIS POINT, SOLUTIONS ARE NOT
CONSISTENT IN THE MODELS AND THE SUPERBLEND IS AN AMALGAM OF BOTH
THE WETTER SOLUTION AND THE MORE SPARSE WITH THE QPF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 600 AM CDT SAT AUG 22 2015
TWO PRIMARY FORECAST CONCERNS THIS PERIOD. THE FIRST BEING HOW FAR
EAST THE CONVECTION OVER CENTRAL MISSOURI GOES THIS MORNING AND
WHETHER THE MORE ORGANIZED CONVECTION EXPECTED TO DEVELOP OUT IN
WESTERN IOWA LATE THIS AFTERNOON MAKES IT INTO OUR WESTERN TAF
SITES BY MIDNIGHT. OTHERWISE...MAINLY VFR CONDITIONS ARE EXPECTED
THIS FORECAST PERIOD. SOUNDING DATA DOES SUGGEST SOME LOWER VFR
CIGS (4000-6000 FEET) WILL TRACK EAST INTO SPI AND POSSIBLY DEC
LATER THIS MORNING WITH MOST OF THE SHORT TERM MODEL SOLUTIONS
INDICATING THAT THE LOWER CLOUD DECK WILL HAVE A DIFFICULT TIME
MAKING IT MUCH FURTHER EAST THAN DECATUR. A COLD FRONT WILL PUSH
EAST OUT OF THE MISSOURI VALLEY LATER THIS EVENING WITH A LINE
OF STORMS EXPECTED TO WEAKEN AFTER 03Z AS IT APPROACHES THE
MISSISSIPPI RIVER. WILL CARRY A VCTS IN THE 03Z-06Z TIME FRAME
FOR PIA AND SPI WITH LATER FORECAST TIMES FOR POINTS FURTHER
EAST LATE TONIGHT.
SURFACE WINDS WILL INCREASE FROM A SOUTHEAST DIRECTION TODAY WITH
SPEEDS OF 10 TO 15 KTS WITH AN OCCASIONAL HIGHER GUST APPROACHING
20 KTS POSSIBLE THIS AFTERNOON. SOUTHEAST WINDS OF 7 TO 12 KTS ARE
EXPECTED TONIGHT. FORECAST SOUNDINGS DO INDICATE THE POTENTIAL FOR
NON-CONVECTIVE LOW LEVEL WIND SHEAR LATE THIS EVENING WITH SURFACE
WINDS OUT OF THE SOUTHEAST AT 7 TO 12 KTS AND OUT OF THE SOUTHWEST
AT 25 TO 35 KTS AROUND 1200 FEET AGL. HOWEVER...WITH THE POTENTIAL
FOR CONVECTION TO BE MOVING INTO PARTS OF THE AREA AT THIS
TIME...WILL NOT ADD LLWS INTO THE FORECAST.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...07
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
601 AM CDT SAT AUG 22 2015
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
MOST OF OUR AREA STILL UNDER THE INFLUENCE OF HIGH PRESSURE WHICH
HAS SHIFTED INTO SOUTHEAST OHIO EARLY THIS MORNING. MEANWHILE TO
OUR SOUTHWEST...A WEAK SHORTWAVE WAS TRACKING EAST ACROSS WESTERN
MISSOURI WITH SHORT TERM MODELS CONTINUING TO SUGGEST SHOWERS AND
STORMS WILL EXPAND IN COVERAGE EARLY THIS MORNING AS THE UPPER LEVEL
WAVE TRACKS EAST. HOWEVER...BOTH THE RAP-13 AND HRRR MODELS HAVE
OVERDONE THE PRECIP ACROSS SOUTHWEST MISSOURI EARLY THIS
MORNING...ESPECIALLY COMPARED TO WHAT IS ACTUALLY OCCURRING NOW.
FORECAST SOUNDINGS INDICATE A BIT MORE CLOUD COVER OVER OUR WEST AND
SOUTHWEST COUNTIES AHEAD OF THE AFOREMENTIONED WAVE TODAY WITH SOME
850 MB MOISTURE CONVERGENCE SEEN ON THE MODELS THIS MORNING OVER
PARTS OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...ESPECIALLY LATE
THIS MORNING...TOWARDS 18Z. HAVE ADDED SOME SLIGHT CHANCE POPS OVER
FAR WEST AND SOUTHWEST IL FOR THIS MORNING INTO EARLY THIS AFTERNOON
JUST AHEAD OF THE WEAKENING UPPER WAVE. FURTHER EAST AND NORTH...
LESS CLOUD COVER SHOULD ALLOW AFTERNOON TEMPS TO RISE INTO THE LOW
TO MID 80S BASED OFF THE RAP SOUNDINGS.
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
RAIN CHANCES INCREASING OVERNIGHT AND INTO TOMORROW AS A COLD FRONT
APPROACHES THE FORECAST AREA. PASSAGE OF THE COLD FRONT EXPECTED IN
THE EARLY MORNING HOURS THROUGH MIDDAY. WITH A LACK OF DIURNAL
HEATING IN THE AIRMASS OUT AHEAD OF THE BOUNDARY, HAVE PULLED THE
MAX TEMPS DOWN A COUPLE DEGREES. SOUTHEAST MAY REMAIN SOMEWHAT
WARMER FOR SUNDAYS HIGHS AND ILX WILL LIKELY HAVE QUITE A GRADIENT
OVER THE REGION. WITH THE GENERAL EARLINESS OF THE SYSTEM, LITTLE TO
NO SEVERE WEATHER IS EXPECTED. BEHIND THE COLD FRONT, HIGH PRESSURE
BUILDS BACK IN AT THE SURFACE. IN THE COOLER AIRMASS, THE TEMPS WILL
REMAIN SLIGHTLY BELOW NORMAL THROUGH MIDWEEK...BUT TRENDING WARMER.
THE WARM TREND WILL BE ENHANCED EVEN FURTHER AS THE HIGH PRESSURE
RIDGE AXIS SLIPS OFF TO THE EAST AND THE SFC WINDS BECOME MORE
SOUTHERLY AHEAD OF THE NEXT FRONT. AT THIS POINT, SOLUTIONS ARE NOT
CONSISTENT IN THE MODELS AND THE SUPERBLEND IS AN AMALGAM OF BOTH
THE WETTER SOLUTION AND THE MORE SPARSE WITH THE QPF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 600 AM CDT SAT AUG 22 2015
TWO PRIMARY FORECAST CONCERNS THIS PERIOD. THE FIRST BEING HOW FAR
EAST THE CONVECTION OVER CENTRAL MISSOURI GOES THIS MORNING AND
WHETHER THE MORE ORGANIZED CONVECTION EXPECTED TO DEVELOP OUT IN
WESTERN IOWA LATE THIS AFTERNOON MAKES IT INTO OUR WESTERN TAF
SITES BY MIDNIGHT. OTHERWISE...MAINLY VFR CONDITIONS ARE EXPECTED
THIS FORECAST PERIOD. SOUNDING DATA DOES SUGGEST SOME LOWER VFR
CIGS (4000-6000 FEET) WILL TRACK EAST INTO SPI AND POSSIBLY DEC
LATER THIS MORNING WITH MOST OF THE SHORT TERM MODEL SOLUTIONS
INDICATING THAT THE LOWER CLOUD DECK WILL HAVE A DIFFICULT TIME
MAKING IT MUCH FURTHER EAST THAN DECATUR. A COLD FRONT WILL PUSH
EAST OUT OF THE MISSOURI VALLEY LATER THIS EVENING WITH A LINE
OF STORMS EXPECTED TO WEAKEN AFTER 03Z AS IT APPROACHES THE
MISSISSIPPI RIVER. WILL CARRY A VCTS IN THE 03Z-06Z TIME FRAME
FOR PIA AND SPI WITH LATER FORECAST TIMES FOR POINTS FURTHER
EAST LATE TONIGHT.
SURFACE WINDS WILL INCREASE FROM A SOUTHEAST DIRECTION TODAY WITH
SPEEDS OF 10 TO 15 KTS WITH AN OCCASIONAL HIGHER GUST APPROACHING
20 KTS POSSIBLE THIS AFTERNOON. SOUTHEAST WINDS OF 7 TO 12 KTS ARE
EXPECTED TONIGHT. FORECAST SOUNDINGS DO INDICATE THE POTENTIAL FOR
NON-CONVECTIVE LOW LEVEL WIND SHEAR LATE THIS EVENING WITH SURFACE
WINDS OUT OF THE SOUTHEAST AT 7 TO 12 KTS AND OUT OF THE SOUTHWEST
AT 25 TO 35 KTS AROUND 1200 FEET AGL. HOWEVER...WITH THE POTENTIAL
FOR CONVECTION TO BE MOVING INTO PARTS OF THE AREA AT THIS
TIME...WILL NOT ADD LLWS INTO THE FORECAST.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS DES MOINES IA
639 AM CDT SAT AUG 22 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
ISSUED AT 327 AM CDT SAT AUG 22 2015
A VERY POTENT 500MB TROUGH WILL CONTINUE TO DEEPEN THROUGHOUT THE
DAY AS EJECTS OUT OF THE NORTHERN ROCKIES INTO THE DAKOTAS THIS
AFTERNOON. THE SURFACE LOW LOOKS TO DEVELOP AND STRENGTHEN OVER
THE EASTERN PORTIONS OF THE DAKOTAS WITH A SHARP COLD FRONT
EXTENDING SOUTHWARD INTO NEBRASKA BY MIDDAY TODAY AND THEN
TRANSITION SOUTHEAST INTO NORTHWEST IOWA LATE IN THE PERIOD.
TROUGH BECOMES NEGATIVELY TILTED BY AROUND 00Z SUNDAY. THERE IS A
LOW POTENTIAL FOR SOME ELEVATED STORMS TO TRY AND DEVELOP OVER
WESTERN TO NORTHWEST PORTIONS OF IOWA AHEAD OF THE COLD
FRONT...BUT WITH A VERY STRONG CAP IN PLACE...HAVE LOW CONFIDENCE
WITH ANYTHING WIDESPREAD AND THUS ANY SEVERE WX PRIOR TO THE FROPA
AND LEFT FORECAST DRY UNTIL 21Z.
THE HIRES 22.00Z ARW/NMM...22.00Z NSSL-WRF...22.05Z HRRR AND
COUPLE MEMBERS OF THE 22.03Z HOPWRF ALL SUGGEST CONVECTIVE
INITIATION B/T 21-23Z OVER FAR NORTHWEST IOWA. ACROSS THE WEST TO
NORTHWEST SECTIONS OF THE FORECAST AREA...DEEP LAYER SHEAR
INCREASES TO 40-45 KNOTS PAST 21Z WITH 0-1KM AND 0-3KM SHEAR BOTH
IN THE 20-30 KNOT RANGE. STRONG SURFACE BASE CAPE INCREASES TO
3000-3800 J/KG WITH STEEP LAPSE RATES IN THE 7.5-8 C/KM RANGE. LCL
HEIGHTS AROUND 600M IN THE WARM SECTOR AND EXPECTING DISCRETE
SUPERCELLS WITH INITIATION THIS AFTERNOON. HOWEVER...THE MOST
LIKELY SCENARIO IS STORMS LOOK TO QUICKLY EVOLVE INTO QLCS SQUALL
LINE BY TIME THEY MOVE INTO THE FORECAST AREA. THERE IS A
POTENTIAL FOR SUPERCELLS TO CREEP INTO THE FAR WESTERN TO
NORTHWESTERN EDGES OF THE FORECAST AREA (DENISON TO ESTHERVILLE
LINE) PRIOR TO THE SQUALL LINE EVOLUTION...AND HAVE POPS
INTRODUCED BY 21Z. ALL MODES OF SEVERE WEATHER POSSIBLE LATE THIS
AFTERNOON...WITH TORNADIC AND LARGE HAIL POTENTIAL UPON INITIATION
AND THEN MORE LIKELY DAMAGING WINDS WITH THE SUPERCELLS EVOLVING
INTO QLCS. CERTAINLY CANNOT RULE TORNADIC POTENTIAL WITHIN THE
QLCS LATE IN THE PERIOD. REGARDLESS...HAVE SEVERE MENTIONED PAST
21Z IN THE FAR NORTHWEST TO COINCIDE WITH SPC ENHANCED RISK AREA.
.LONG TERM /TONIGHT THROUGH FRIDAY/...
ISSUED AT 327 AM CDT SAT AUG 22 2015
ONGOING SEVERE WEATHER AND HEAVY RAINFALL EXPECTED EARLY IN THE
FIRST PERIOD. SEVERAL FACTORS POINT TO A ROBUST LINE OF CONVECTION
THIS EVENING. A STRONG COLD FRONT WITH IMPRESSIVE SFC
CONVERGENCE ...STRONG INSTABILITY/HIGH PRECIPITABLE WATER AND
APPROACHING H500 WAVE WILL COMBINE TO ENHANCE CONVECTION THROUGH
AT LEAST 06Z. MAIN CONCERNS AFTER 02Z WILL BE THREAT FOR WIND/HAIL
AND HEAVY RAINFALL. GFS BUFR SOUNDINGS AT 00Z SHOW 0-3KM SRH ABOUT
200-300 J/KG AT KDSM AS THE LINE REACHES CENTRAL IA AT THAT TIME
WITH STORM RELATIVE HELICITY WEAKENING TOWARD 06Z IN THE
SOUTHEAST. SBCAPE IS PROGGED TO BE 2750 WITH LCL OF NEAR
692M/2000FT. INITIALLY THE THREAT THROUGH ABOUT I35 WILL STILL
INCLUDE THE RISK OF A TORNADO THOUGH ANY DISCRETE SUPERCELLS IN
THE LATE AFTERNOON SHOULD BE EVOLVING INTO A MORE LINEAR AND
ACCELERATING LINE OF STORMS AS IT MOVES MORE RAPIDLY SOUTHEAST
WITH TIME. THROUGH THE EVENING HOURS THE THREAT FOR SEVERE WEATHER
WILL GRADUALLY WEAKEN AS BOTH CAPE AND HELICITY BEGIN TO LESSEN
WITH TIME. THE OTHER CONCERN WITH THIS EVENT WILL BE BRIEF BUT
VERY HEAVY RAINFALL. SUBJECTIVE 00Z SATURDAY H850 ANALYSIS THIS
EVENING SHOWS A +15C PLUME OF MOISTURE FROM THE TEXAS COAST UP
INTO CENTRAL/WESTERN NEBRASKA. THE GFS IS FORECASTING PRECIPITABLE
WATER OF UP TO 1.7 INCHES ALONG THE BOUNDARY IN WESTERN IA AT
18Z...AND A MORE BROAD AREA OF 1.75 TO AROUND 2 INCHES FROM
CENTRAL THROUGH SOUTHEAST IA FROM 00-06Z TONIGHT. THIS COMBINED
WITH AN EXPECTED WARM CLOUD DEPTH OF 3600-3800M (>12KFT) OVER
WESTERN IOWA...INCREASING TO OVER 4000M (>13KFT) FROM TAMA TO
DECATUR COUNTY BY 06Z WILL PROMOTE INCREASINGLY EFFICIENT RAINFALL
AS THE LINE BECOMES MORE ORGANIZED AND 0-6KM BULK SHEAR 50-60KTS
BEHIND THE BOUNDARY CATCHES UP TO THE LINE FROM 03-06Z. NMM
MOISTURE CONVERGENCE AND MOISTURE TRANSPORT VECTORS ARE BOTH
MAXIMIZED AT THIS TIME OVER CENTRAL/SOUTHERN IOWA. FOR NOW AM
ANTICIPATING AT LEAST A PERIOD OF 1-2 HOURS OF 1-2 INCH
RAINFALL/HOUR MAINLY FROM 03-06Z FROM NEAR AMES SOUTHWEST TO
CRESTON/LAMONI OR GENERALLY SOUTH OF HIGHWAY 30 AND ALONG AND WEST
OF I35. CURRENT 1HR GRIDDED FLASH FLOOD GUIDANCE IS RUNNING ABOUT
1.75 TO NEARLY 2 INCHES OVER MOST OF THIS REGION AND HIGH ENOUGH
TO AVOID A HEADLINE FOR FLASH FLOODING. HOWEVER...THE TIMING OF
THE RAINFALL AND LIKELIHOOD THAT IT WILL FALL DURING THE LATE
EVENING HOURS ON A WEEKEND EVENING OVER URBAN AREAS IS A CONCERN.
PONDING OF WATER AND SOME STREET FLOODING COULD BE A PROBLEM
ACROSS MOSTLY URBAN AREAS. EVENTUALLY THE LINE WILL BE NEARLY OUT
OF THE AREA BY 10-13Z AS THE FORWARD MOTION TAKES IT INTO NORTHERN
MO AND SOUTHEAST IA BY 13Z.
THE REMAINDER OF THE FORECAST IS FAIRLY BENIGN. ONCE THE VIGOROUS
H500 TROUGH MOVE EAST INTO THE GREAT LAKES SUNDAY INTO MONDAY MUCH
COOLER AND DRIER WEATHER WILL BE EXPECTED FROM SUNDAY THROUGH
TUESDAY. A GRADUAL WARMING TREND IS EXPECTED FROM WEDNESDAY THROUGH
FRIDAY WITH A WEAK WAVE IMPACTING THE REGION ON THURSDAY. HIGHS WILL
WARM FROM THE LOWER TO MID 70S EARLY IN THE PERIOD TO THE MID 70S TO
LOWER 80S LATE IN THE PERIOD. LOWS RECOVER FROM THE 40S/50S TO THE
50S/60S LATER IN THE PERIOD.
&&
.AVIATION...22/12Z
ISSUED AT 636 AM CDT SAT AUG 22 2015
WINDY CONDITIONS EXPECTED LATER THIS MORNING INTO THE AFTERNOON
HOURS AS GOOD MIXING AND STRONG PRESSURE GRADIENT DEVELOP.
INCREASED SUSTAINED AND GUSTS ACROSS ALL TAF SITES. INTRODUCED IFR
VIS AND LOWER MVFR CIGS FOR LATE THIS AFTERNOON INTO THE EVENING
FOR TIMING OF STORMS. NO SEVERE WINDS MENTIONED ATTM BUT CERTAINLY
THE BEST POTENTIAL IS AT MCW/FOD/DSM. WEST TO NORTHWEST WINDS
DEVELOP BEHIND THE COLD FRONT LATE TONIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...PODRAZIK
...UPDATE TO AVIATION FORECAST DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SAT AUG 22 2015
THIS MORNING, MULTIPLE PIECES OF EMBEDDED VORTICITY MAXIMA IN THE
MID LEVELS WERE PROGRESSING EASTWARD THROUGH THE PLAINS. STRONGER
ISENTROPIC UPGLIDE HAD DEVELOPED A CLUSTER OF STORMS OVER FAR
NORTHERN OK INTO SOUTHEAST KS. THERE IS A SMALL CHANCE THE REMNANT
OUTFLOW FROM THIS CLUSTER WILL DEVELOP SCT SHOWERS/ISO THUNDER
OVER FAR EAST CENTRAL KS THROUGH SUNRISE. WHAT IS MORE LIKELY IS
DRY CONDITIONS AND OVERCAST SKIES THROUGH THE MORNING BEFORE
SUBSIDENCE CLEARS CLOUD DECK EASTWARD BY THE AFTERNOON. HIGH TEMPS
TODAY ARE STILL ON TRACK TO BE A FEW DEGREES WARMER IN THE UPPER
80S TO LOWER 90S. RAISED DEWPOINT TEMPS THIS AFTERNOON AS MOST
SHORT TERM GUIDANCE ADVECTS READINGS IN THE LOWER 70S, ESPECIALLY
OVER FAR EASTERN KANSAS. THE RESULT OF THE HIGHER MOISTURE WILL
LIKELY ALLOW FOR HIGHER INSTABILITY TO BUILD UNDER A DECENT EML
THROUGH THE AFTERNOON. THIS CAPPING INVERSION SHOULD INHIBIT
DEVELOPMENT UNTIL THE COLD FRONT APPROACHES FROM NEBRASKA. BELIEVE
THE NAM REMAINS ON THE HIGH BIAS WITH MID 70S DEWPOINTS AND CAPE
PEAKING NEAR 4000 J/KG, HOWEVER WOULD NOT BE SURPRISED TO SEE MOST
AREAS IN THE 2500 TO 3500 J/KG CATEGORY BY 4 PM. GIVEN THE SETUP,
SEVERE WEATHER POTENTIAL REMAINS LIKELY BEGINNING LATE THIS
AFTERNOON INTO THE EVENING HOURS. DETAILS TO FOLLOW.
WITH THE STRONG CAPPING INVERSION IN PLACE DURING THE AFTERNOON, THE
MAIN AREA OF ASCENT TO LIFT THESE SFC PARCELS WILL FOCUS ALONG THE
COLD FRONT THAT IS CURRENTLY TRACKING SOUTHEAST FROM NORTHERN CO TO
CENTRAL SD. THIS FRONT WILL QUICKLY TRAVERSE NEBRASKA THROUGH THE
DAY, WITH ALL GUIDANCE DEVELOPING QPF NEAR THE FRONT BETWEEN 5 PM
AND 7 PM ACROSS COUNTIES NEAR THE KS AND NE BORDER. SHORT AND MID
TERM GUIDANCE IS STILL IN GOOD AGREEMENT IN FORMING A LINE OF
CONVECTION THAT QUICKLY RACES SOUTHEAST THROUGH NORTHEAST KS DURING
THE EVENING AND OVERNIGHT PERIODS. RAP AND NAM FORECAST SOUNDINGS
SHOW NICELY CURVED HODOGRAPHS WITH 0-3 KM SRH VALUES AT OR ABOVE 150
M2/S2 WHILE LOW LEVEL SHEAR MAXIMIZES NEAR 20 KTS. IF STORMS ARE
ABLE TO FORM IN THIS ENVIRONMENT DURING THE LATE AFTERNOON/EARLY
EVENING TIME FRAME, THERE IS A POSSIBILITY FOR AN ISOLATED TORNADO
TO FORM, ESPECIALLY LOCATIONS NORTH OF INTERSTATE 70 WHERE BETTER
WIND PROFILES EXIST. OTHERWISE, STEEP MID LEVEL LAPSE RATES AND
AMPLE MUCAPE WILL CARRY THE SEVERE POTENTIAL FOR LARGE HAIL AND
DAMAGING WIND GUSTS ACROSS THE ENTIRE CWA. BRIEF HEAVY RAINFALL IS
EXPECTED WITH SOME AREAS PICKING UP OVER AN INCH BY SUNRISE. THE
MAIN CHANGE WITH THIS UNSEASONABLY STRONG SYSTEM IS ADJUSTING WINDS
AND TEMPS AS THE SPEED OF THE FRONT IS A BIT FASTER THAN PREVIOUS
RUNS. THIS MAY ALSO FURTHER HEIGHTEN THE STRONG WIND POTENTIAL.
SUBSIDENCE AND CLEAR SKIES MOVE IN QUICKLY BEHIND THE LINE, OPTING
FOR LOWER TEMPS IN THE LOWER 50S NORTH TO LOW 60S SOUTH SAT
MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT AUG 22 2015
THE COLD FRONT IS EXPECTED TO BE THROUGH THE FORECAST AREA BY
SUNDAY MORNING. THEREFORE THE PRECIP SHOULD BE OVER AS COLD AIR
ADVECTION STABILIZES THE ATMOSPHERE. HIGHS SUNDAY SHOULD BE IN
THE MID AND UPPER 70S DUE TO THE COLD AIR ADVECTION. MONDAY
MORNING SHOULD BE THE COOLEST AS THE CENTER OF THE SURFACE RIDGE
PASSES THROUGH THE AREA. WITH CLEAR SKIES AND LIGHT WINDS, LOWS
ARE EXPECTED TO DROP TO THE LOWER 50S OR AROUND 50.
NEXT WEEK SHOULD BE QUIET FOR THE MOST PART. MODELS CONTINUE TO
AMPLIFY AN UPPER RIDGE JUST WEST OF THE FORECAST AREA. THIS
BLOCKING PATTERN MAKES IT DIFFICULT FOR ANY WAVE OF SUBSTANCE TO
AFFECT THE FORECAST AREA, AND THERE IS LITTLE CONFIDENCE IN THE
GFS SOLUTIONS AND THE TRANSIENT VORT MAXIMUM IT DEVELOPS. HAVE
LEANED MORE TOWARDS THE ECMWF WHICH AT A LOWER RESOLUTION, TENDS
TO KEEP WEAK NORTHWESTERLY FLOW WITHOUT THE SMALL SCALE
PERTURBATIONS THROUGH MID WEEK. BY FRIDAY, THE ECMWF/GFS/CANADIAN
SEEM TO BRING A LITTLE BETTER DEFINED WAVE OVER THE TOP OF THE
UPPER RIDGE WITH A WEAK BOUNDARY. BECAUSE OF THIS HAVE SOME SMALL
POPS IN FOR THURSDAY NIGHT AND FRIDAY. MODELS SHOW A SIMILAR
AIRMASS RESIDING OVER THE AREA THROUGH THE WEEK. SO AFTER A COOL
START ON MONDAY, TEMPS SHOULD MODERATE WITH RISING HEIGHTS. HIGHS
ARE FORECAST TO BE IN THE 80S WHILE LOWS GRADUALLY TREND WARMER
FROM THE MID 50S TUESDAY TO THE MID 60S FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 634 AM CDT SAT AUG 22 2015
SCT TSRA THIS MORNING IS EXPECTED TO REMAIN SOUTH OF TERMINALS
WITH NO IMPACTS. SOUTHERLY WINDS INCREASE ABOVE 10 KTS AFT 16Z
WITH GUSTS COMMONLY ABOVE 20 KTS. CONFIDENCE IS HIGH IN A LINE OF
TSRA FORMING ALONG A COLD FRONT, TRACKING SOUTHEAST OVER TERMINALS
IN THE 03Z TO 05Z TIME FRAME. MVFR CONDITIONS ARE LIKELY AND MAY
OCCASIONALLY BE IFR OR LOWER WITHIN A HEAVIER SHOWER. WINDS QUICKLY
VEER TO THE NORTH WITH SEVERE WIND GUSTS POSSIBLE WITHIN CONVECTION.
ALL ACTIVITY CLEARS TERMINALS AFT 09Z WITH RETURN TO VFR.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BOWEN
LONG TERM...WOLTERS
AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1005 AM EDT SAT AUG 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION AND STALL ACROSS DOWNEAST MAINE
THIS AFTERNOON WHILE HIGH PRESSURE BUILDS IN BRIEFLY ACROSS THE
NORTHERN AREAS. THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS
A WARM FRONT SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1005 AM UPDATE...THE FRONT REMAINS POISED ACROSS DOWNEAST MAINE
THIS MORNING AND WILL CONTINUE TO VERY SLOWLY MOVE SOUTH THROUGH
THE DAY. SCATTERED SHOWERS ARE CURRENTLY RIDING UP JUST AHEAD OF
THE FRONT. THE LATEST HRRR IS DOING A PRETTY GOOD JOB WITH MODELED
RADAR, AND IT KEEPS SHOWERS WITH ISOLATED THUNDER ACROSS DOWNEAST
THROUGH THE EVENING. IT HINTS THAT THE GREATEST CONCENTRATION WILL
BE ACROSS NORTHERN PORTIONS OF WASHINGTON AND HANCOCK COUNTIES,
WITH POSSIBLE TRAINING CELLS. HAVE THEREFORE INCREASED POPS IN
THESE AREAS TO LIKELY FOR THE AFTERNOON. OTHERWISE, JUST MADE
SLIGHT ADJUSTMENTS TO THE SKY COVER. NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...SURFACE ANALYSIS HAD THE COLD FRONT SLOWLY
WORKING ITS WAY E ACROSS WESTERN MAINE. AREAS OF FOG ALONG THE
IMMEDIATE COAST THIS MORNING. THE LATEST RUN OF THE HRRR KM AND
RAP HAD A GOOD HANDLE ON THINGS ATTM KEEPING HIGHER POPS OVER
EASTERN AREAS THIS MORNING INTO THE AFTERNOON AS THE FRONT SAGS
ESE AND THEN STALLS ACROSS DOWNEAST MAINE COAST. LLVL CONVERGENCE
AND SOME WEAK MID LEVEL FORCING WILL ALLOW FOR SHOWERS TO CONTINUE
ACROSS THE AFOREMENTIONED AREAS INTO EARLY EVENING. INSTABILITY IS
THERE ESPECIALLY FOR WASHINGTON AND HANCOCK COUNTY. SOUNDING DATA
SUPPORTED SBCAPES OF 500-800 JOULES AND LIS DOWN TO -3 W/PWATS OF
1.8+ INCHES. LOW/MID LEVEL LAPSE RATES OF 6.2 C/KM EXPECTED, SO
TSTM POTENTIAL IS THERE. HIGH FREEZING LEVELS AND WBZS(14K FT)
WILL ALLOW FOR ANY TSTMS TO CONTAIN HEAVY RAINFALL. 0-6KM SHEAR
AROUND 12 KTS W/SW FLOW THROUGH 700MBS WILL ALSO ALLOW ANY STORMS
TO TRAIN OVER THE SAME AREAS. THIS ALL HINGES ON HEATING POTENTIAL
WHICH COULD BE DELAYED FOR A WHILE. THEREFORE, DECIDED TO CARRY
TSTMS FOR THE DOWNEAST ESPECIALLY HANCOCK AND WASHINGTON COUNTY
BUT LEFT OUT ENHANCED WORDING ATTM. WILL TAKE ANOTHER LOOK AT
THINGS W/6 AM UPDATE. FURTHER NORTH ACROSS PISCATAQUIS AND
AROOSTOOK COUNTY, DRIER W/SOME PARTIAL CLEARING EXPECTED.
FOR TONIGHT, THE FRONT LOOKS AS THOUGH IT TRIES TO BUCKLE BACK TO
THE NORTH AS A WEAL UPPER LOW LIFTS ACROSS THE WESTERN ATLC. SHOWERS
EXPECTED TO EDGE A BIT FURTHER NNE INTO CENTRAL PENOBSCOT AND
NORTHERN WASHINGTON COUNTY. FURTHER N AND W., DRIER AND A BIT
COOLER OVERNIGHT. FOG LOOKS TO BE A THREAT OVERNIGHT ESPECIALLY
WHERE RAINFALL OCCURRED. TEMPERATURES ARE EXPECTED TO BE IN THE
UPPER 50S TO LOWER 60S NORTH AND WEST W/MID 60S FOR THE DOWNEAST
AND COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
LOW PRESSURE WILL MEANDER ACROSS THE NW ATLANTIC DURING SUNDAY AS
AN AREA OF HIGH PRESSURE MOVES EAST ACROSS THE MARITIMES. A MOIST
EAST TO SOUTHEAST FLOW AROUND THESE SYSTEMS WILL KEEP A CHANCE OF
SHOWERS AND PERHAPS AN AFTERNOON TSTM TO MAINLY PORTIONS OF
CENTRAL AND DOWN EAST MAINE SUNDAY AFTERNOON. THE LOW WILL SLOWLY
START TO DRIFT EAST MONDAY NIGHT THROUGH TUESDAY. MOISTURE
ASSOCIATED WITH AN APPROACHING TROF FROM THE GREAT LAKES REGION
WILL CONTINUE THE THREAT OF SHOWERS THROUGH MONDAY ALONG WITH THE
CHANCE FOR A FEW AFTERNOON THUNDERSTORMS. HIGH TEMPERATURES BOTH
SUNDAY AND MONDAY WILL BE IN THE MID TO NEAR 80 DEGREES. LOWS
SUNDAY NIGHT WILL BE IN THE 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
UNSETTLED WEATHER CONDITIONS WILL PERSIST THROUGH THURSDAY AS A
TROF OF LOW PRESSURE TO OUR WEST SLOWLY CROSSES THE REGION THROUGH
THURSDAY. THIS WILL BRING A CONTINUED THREAT FOR SHOWERS THROUGH
THURSDAY. WE SHOULD START TO DRY OUT A BIT BY THURSDAY NIGHT AND
FRIDAY BEFORE ANOTHER SYSTEM BRINGS THE CHANCE FOR SHOWERS BY NEXT
WEEKEND.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MVFR FOR KBGR AND IFR/LIFR KBHB THIS MORNING W/VFR
ACROSS THE NORTHERN TERMINALS. SOME IMPROVEMENT EXPECTED FOR KBHB
TO MVFR LATER THIS AFTERNOON. KBGR COULD DROP BACK TO IFR THIS
MORNING BEFORE RECOVERING BACK TO MVFR AND POSSIBLY VFR THIS
AFTERNOON. ACROSS THE NORTH, PERIODS OF MVFR EXPECTED THIS MORNING
W/A RECOVERY TO VFR. FOG POTENTIAL FOR TONIGHT COULD ALLOW
CONDITIONS TO GO TO MVFR NORTH OF KBHB WHILE KBHB DOWN TO IFR.
SHORT TERM: CONDITIONS WILL VARY AT TIMES THROUGH THE PERIOD FROM
VFR DOWN TO IFR IN SHOWERS AND PATCHY MAINLY NIGHTTIME FOG.
&&
.MARINE...
NEAR TERM: NO HEADLINES EXPECTED THIS TERM. SSE SWELL OF 2 FT OUT
THERE ATTM AND A SLIGHT BUILD IN WAVE HEIGHTS EXPECTED TONIGHT.
WINDS WILL REMAIN 10 KTS OR LESS W/FOG A NUISANCE TO NAVIGATION.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS THROUGH THE PERIOD.
&&
.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
704 AM EDT SAT AUG 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION AND STALL ACROSS DOWNEAST MAINE
THIS AFTERNOON WHILE HIGH PRESSURE BUILDS IN BRIEFLY ACROSS THE
NORTHERN AREAS. THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS
A WARM FRONT SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
655 AM UPDATE...ADJUSTED SKY AND TEMPS TO MATCH WITH THE LATEST
CONDITIONS. RADAR SHOWED LINE OF SHOWERS MOVING NE THROUGH HANCOCK
AND WASHINGTON COUNTY. ADJUSTED THE POPS A BIT FURTHER N TO
ACCOUNT FOR RADAR LOOP SHOWING PRECIP MOVING INTO SE AROOSTOOK
COUNTY.
SURFACE ANALYSIS HAD THE COLD FRONT SLOWLY WORKING ITS WAY E
ACROSS WESTERN MAINE. AREAS OF FOG ALONG THE IMMEDIATE COAST THIS
MORNING. THE LATEST RUN OF THE HRRR KM AND RAP HAD A GOOD HANDLE
ON THINGS ATTM KEEPING HIGHER POPS OVER EASTERN AREAS THIS MORNING
INTO THE AFTERNOON AS THE FRONT SAGS ESE AND THEN STALLS ACROSS
DOWNEAST MAINE COAST. LLVL CONVERGENCE AND SOME WEAK MID LEVEL
FORCING WILL ALLOW FOR SHOWERS TO CONTINUE ACROSS THE
AFOREMENTIONED AREAS INTO EARLY EVENING. INSTABILITY IS THERE
ESPECIALLY FOR WASHINGTON AND HANCOCK COUNTY. SOUNDING DATA
SUPPORTED SBCAPES OF 500-800 JOULES AND LIS DOWN TO -3 W/PWATS OF
1.8+ INCHES. LOW/MID LEVEL LAPSE RATES OF 6.2 C/KM EXPECTED, SO
TSTM POTENTIAL IS THERE. HIGH FREEZING LEVELS AND WBZS(14K FT)
WILL ALLOW FOR ANY TSTMS TO CONTAIN HEAVY RAINFALL. 0-6KM SHEAR
AROUND 12 KTS W/SW FLOW THROUGH 700MBS WILL ALSO ALLOW ANY STORMS
TO TRAIN OVER THE SAME AREAS. THIS ALL HINGES ON HEATING POTENTIAL
WHICH COULD BE DELAYED FOR A WHILE. THEREFORE, DECIDED TO CARRY
TSTMS FOR THE DOWNEAST ESPECIALLY HANCOCK AND WASHINGTON COUNTY
BUT LEFT OUT ENHANCED WORDING ATTM. WILL TAKE ANOTHER LOOK AT
THINGS W/6 AM UPDATE. FURTHER NORTH ACROSS PISCATAQUIS AND
AROOSTOOK COUNTY, DRIER W/SOME PARTIAL CLEARING EXPECTED.
FOR TONIGHT, THE FRONT LOOKS AS THOUGH IT TRIES TO BUCKLE BACK TO
THE NORTH AS A WEAL UPPER LOW LIFTS ACROSS THE WESTERN ATLC. SHOWERS
EXPECTED TO EDGE A BIT FURTHER NNE INTO CENTRAL PENOBSCOT AND
NORTHERN WASHINGTON COUNTY. FURTHER N AND W., DRIER AND A BIT
COOLER OVERNIGHT. FOG LOOKS TO BE A THREAT OVERNIGHT ESPECIALLY
WHERE RAINFALL OCCURRED. TEMPERATURES ARE EXPECTED TO BE IN THE
UPPER 50S TO LOWER 60S NORTH AND WEST W/MID 60S FOR THE DOWNEAST
AND COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
LOW PRESSURE WILL MEANDER ACROSS THE NW ATLANTIC DURING SUNDAY AS
AN AREA OF HIGH PRESSURE MOVES EAST ACROSS THE MARITIMES. A MOIST
EAST TO SOUTHEAST FLOW AROUND THESE SYSTEMS WILL KEEP A CHANCE OF
SHOWERS AND PERHAPS AN AFTERNOON TSTM TO MAINLY PORTIONS OF
CENTRAL AND DOWN EAST MAINE SUNDAY AFTERNOON. THE LOW WILL SLOWLY
START TO DRIFT EAST MONDAY NIGHT THROUGH TUESDAY. MOISTURE
ASSOCIATED WITH AN APPROACHING TROF FROM THE GREAT LAKES REGION
WILL CONTINUE THE THREAT OF SHOWERS THROUGH MONDAY ALONG WITH THE
CHANCE FOR A FEW AFTERNOON THUNDERSTORMS. HIGH TEMPERATURES BOTH
SUNDAY AND MONDAY WILL BE IN THE MID TO NEAR 80 DEGREES. LOWS
SUNDAY NIGHT WILL BE IN THE 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
UNSETTLED WEATHER CONDITIONS WILL PERSIST THROUGH THURSDAY AS A
TROF OF LOW PRESSURE TO OUR WEST SLOWLY CROSSES THE REGION THROUGH
THURSDAY. THIS WILL BRING A CONTINUED THREAT FOR SHOWERS THROUGH
THURSDAY. WE SHOULD START TO DRY OUT A BIT BY THURSDAY NIGHT AND
FRIDAY BEFORE ANOTHER SYSTEM BRINGS THE CHANCE FOR SHOWERS BY NEXT
WEEKEND.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MVFR FOR KBGR AND IFR/LIFR KBHB THIS MORNING W/VFR
ACROSS THE NORTHERN TERMINALS. SOME IMPROVEMENT EXPECTED FOR KBHB
TO MVFR LATER THIS AFTERNOON. KBGR COULD DROP BACK TO IFR THIS
MORNING BEFORE RECOVERING BACK TO MVFR AND POSSIBLY VFR THIS
AFTERNOON. ACROSS THE NORTH, PERIODS OF MVFR EXPECTED THIS MORNING
W/A RECOVERY TO VFR. FOG POTENTIAL FOR TONIGHT COULD ALLOW
CONDITIONS TO GO TO MVFR NORTH OF KBHB WHILE KBHB DOWN TO IFR.
SHORT TERM: CONDITIONS WILL VARY AT TIMES THROUGH THE PERIOD FROM
VFR DOWN TO IFR IN SHOWERS AND PATCHY MAINLY NIGHTTIME FOG.
&&
.MARINE...
NEAR TERM: NO HEADLINES EXPECTED THIS TERM. SSE SWELL OF 2 FT OUT
THERE ATTM AND A SLIGHT BUILD IN WAVE HEIGHTS EXPECTED TONIGHT.
WINDS WILL REMAIN 10 KTS OR LESS W/FOG A NUISANCE TO NAVIGATION.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS THROUGH THE PERIOD.
&&
.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 LAS VEGAS NV
846 AM PDT SAT AUG 22 2015
.SYNOPSIS...HAZY CONDITIONS OVER MUCH OF THE AREA WILL IMPROVE OVER
THE WEEKEND AS SMOKE FROM CALIFORNIA WILDFIRES IS STEERED TOWARD
CENTRAL NEVADA. A SHALLOW PUSH OF MOISTURE WILL LEAD TO SLIGHT
CHANCES FOR THUNDERSTORMS OVER MAINLY THE HIGHER TERRAIN OF LINCOLN
AND NORTHERN MOHAVE COUNTIES THIS WEEKEND. DEEPER MOISTURE ARRIVES
EARLY NEXT WEEK AND COULD LINGER THROUGH MID WEEK WHICH WILL RESULT
IN INCREASING COVERAGE OF SHOWERS AND THUNDERSTORMS.
&&
.UPDATE...MINOR MID LEVEL WAVE OVER SOUTHERN CALIFORNIA PROGGED TO
CONTINUE EAST INTO SOUTHERN NEVADA THIS AFTERNOON. ADDITIONAL LIFT
PROVIDED BY WAVE SHOULD BE ENOUGH FOR ISOLATED SHOWERS/THUNDERSTORMS
PRIMARILY OVER EASTERN LINCOLN COUNTY AND NORTHERN MOHAVE COUNTY
THIS AFTERNOON/EARLY EVENING. HRRR AND HI-RES MODELS SUPPORT CURRENT
POPS SO NO UPDATE NEEDED.
AS FOR SMOKE FROM THE ROUGH FIRE. A SLIGHT SHIFT IN THE WINDS LOOKS
TO HAVE TAKEN MUCH OF THE SMOKE FROM YESTERDAY NORTHEAST INTO
CENTRAL NEVADA. BISHOP AND TONOPAH HAVE BEEN REPORTING VISIBILITIES
BETWEEN 7 AND 10 MILES MOST OF THE NIGHT.
&&
.PREV DISCUSSION...250 AM PDT SAT AUG 22 2015
.SHORT TERM...THROUGH MONDAY NIGHT.
ANOTHER SEASONABLY WARM AND MOSTLY DRY DAY IS EXPECTED ACROSS THE
REGION TODAY. ONE NOTABLE CHANGE OVER YESTERDAY IS THAT DESPITE A
MODEST MOISTURE INCREASE AND INSTABILITY ACROSS THE AREA
YESTERDAY...NO THUNDERSTORMS WERE ABLE TO FORM DUE TO LARGE SCALE
SUBSIDENCE OVER THE REGION. THINGS TODAY LOOK A LITTLE MORE
PROMISING AS A WEAK SHORTWAVE WILL BE LIFTING ACROSS THE AREA THIS
AFTERNOON AND INTERACTING WITH SOME OF THE MARGINAL INSTABILITY THAT
IS IN PLACE ACROSS MAINLY LINCOLN AND NORTHERN MOHAVE COUNTIES.
EARLY MORNING RUNS OF THE HRRR BREAK OUT ISOLATED STORMS ACROSS
LINCOLN COUNTY BETWEEN 1PM AND 2PM AND WITH THE WEAK SHORT WAVE
PUSHING THROUGH...THERE SHOULD BE JUST ENOUGH LIFT TO SUPPORT THIS.
THE LOWER ATMOSPHERE ESPECIALLY IN LINCOLN COUNTY IS STILL A BIT
DRY...SO GUSTY DOWNBURST WINDS AND LIGHTNING ACCOMPANIED BY LITTLE
RAIN WILL BE THE PRIMARY THREATS. OTHERWISE...FORECAST OUTSIDE OF
THE ABOVE MENTIONED AREAS WILL BE DRY.
ON SUNDAY...ANY THUNDERSTORM ACTIVITY LOOKS TO BE CONFINED TO FAR
EASTERN MOHAVE COUNTY BEFORE A STRONGER PUSH OF MONSOON MOISTURE
NUDGES INTO THE AREA ON MONDAY. PRECIPITABLE WATER VALUES BY MONDAY
AFTERNOON RISE INTO THE INCH TO INCH AND A HALF RANGE ACROSS THE
LOWER COLORADO RIVER VALLEY...AND THIS MOISTURE CONTENT ADVECTS
NORTHWARD OVERNIGHT INTO SOUTHERN NEVADA AND EASTERN CALIFORNIA. THE
ARRIVAL OF THIS DEEPER MOISTURE (AIDED BY A RATHER VIGOROUS INVERTED
TROUGH) MAY ALLOW FOR NOCTURNAL CONVECTION MONDAY NIGHT ACROSS AREAS
SOUTH OF INTERSTATE 15. HEAVY RAIN AND STRONG WINDS WILL BE THE
PRIMARY THREATS WITH STORMS MONDAY AND MONDAY NIGHT.
.LONG TERM...TUESDAY THROUGH FRIDAY.
THE LATEST OPERATIONAL MODEL RUNS REMAIN IN GOOD LARGE SCALE
AGREEMENT THIS EVENING FOR THE LONG TERM PERIOD. BOTH THE 00Z RUNS
OF THE GFS AND ECMWF REMAIN CONSISTENT WITH PREVIOUS RUNS REGARDING
THE TIMING AND STRENGTH OF A WELL-DEFINED VORTICITY MAX THAT IS
PROGGED TO BE IN THE PROCESS OF TRAVERSING EASTERN PORTIONS OF THE
CWA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. AS MENTIONED IN THE
PREVIOUS DISCUSSION...THE ECMWF CONTINUES TO PLACE THE CENTER OF THE
FOUR CORNERS HIGH FURTHER WEST THAN THE GFS DOES...LEADING TO A
SLIGHT DELAY IN MOISTURE RETURN AND YIELDING MUCH WARMER
TEMPERATURES TUESDAY ONWARD. DESPITE THE DIFFERENCES IN EXACT
DETAIL...RAISED THUNDERSTORM CHANCES ACROSS THE EASTERN HALF OF THE
FORECAST AREA TUESDAY AND WEDNESDAY TO ACCOUNT FOR THIS FEATURE AND
THE INCREASE IN MOISTURE ACROSS THE AREA. THE MOST FAVORABLE LOCALES
FOR THUNDERSTORMS THROUGH THIS PERIOD APPEARS TO BE MOHAVE COUNTY AT
THIS TIME...THOUGH ACTIVITY COULD POSSIBLY STRETCH AS FAR WEST AS
PORTIONS OF SAN BERNARDINO...INYO...AND NYE COUNTIES.
A WARMUP IN AFTERNOON HIGH TEMPERATURES IS EXPECT FOR THE LATTER
PART OF THE WEEK...AS THE CENTER OF HIGH PRESSURE RETROGRADES
WESTWARD THROUGH THE END OF THE WEEK. WITH NO APPRECIABLE DRY
SOUTHWESTERLY TO WESTERLY FLOW PROGGED OVER THE AREA...THE
LIKELIHOOD OF LOW TO MID-LEVEL MOISTURE GETTING SCOURED OUT IS
LOW...THUS MITIGATING THE AMOUNT OF WARMING THAT WILL OCCUR AS THE
HIGH MOVES OVER THE AREA. FOR THIS REASON...DECIDED TO LEAN AWAY
FROM THE ECMWF OUTPUTS THAT CONTINUE TO APPROACH EXCESSIVE HEAT
CRITERIA BY THE WEEKS END. HOWEVER...HAVE BUMPED UP INHERITED TEMPS
FOR THURSDAY THROUGH SATURDAY...INDICATING A GRADUAL WARMUP TO ABOVE
AVERAGE HIGHS BY THE WEEKEND. OTHERWISE...GENERALLY DRY CONDITIONS
ARE EXPECTED.
&&
.AVIATION...FOR MCCARRAN...LIGHTER WINDS EXPECTED TODAY COMPARED TO
YESTERDAY WITH LIGHT AND VARIABLE WINDS FAVORING EASTERLY COMPONENTS
EXPECTED FROM 15Z-21Z BEFORE TRANSITIONING TO A MORE SOUTH-SOUTHWEST
DIRECTION BY 00Z WITH SPEEDS IN THE 9-12KT RANGE WITH GUSTS TO
20KTS. CONFIDENCE IN THE TIMING OF THOSE STRONGER WINDS IS LOW AND
MAY OCCUR AS EARLY AS 21Z OR AS LATE AS 00Z. GUSTY WINDS SHOULD
TAPER OFF AFTER 3Z.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GENERALLY FAIR WEATHER EXPECTED ACROSS THE AREA WITH
AREAS OF SMOKE AND HAZE ESPECIALLY ACROSS INYO COUNTY AND OWENS
VALLEY REGION. AFTERNOON BREEZES OF 10-15KTS WITH GUSTS TO 20KTS ARE
EXPECTED OUT OF THE SOUTH AFTER 21Z AND PERSISTING THROUGH 3Z.
ISOLATED THUNDERSTORMS ARE POSSIBLE NORTH OF LAS VEGAS IN LINCOLN
COUNTY AND ALSO ACROSS FAR NORTHWEST ARIZONA.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE...PIERCE
SHORT TERM/AVIATION...OUTLER
LONG TERM...PULLIN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
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AREA FORECAST DISCUSSION
NWS BISMARCK ND
935 AM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 923 AM CDT SAT AUG 22 2015
WINDS GENERALLY IN THE ADVISORY CRITERIA SOUTHWEST SO FAR TODAY.
WILL KEEP THE HIGH WIND WARNING GOING AS EXPECT THE GRADIENT WIND
TO INCREASE. ADJUSTED THE POPS TO FIT THE CURRENT SHOWERS. SEEING
FAIRLY WIDESPREAD SHOWERS NORTH CENTRAL WITH SCATTERED T. EXPECT
THE SHOWERS TO FILL IN WITH TIME WEST AND SOUTH CENTRAL.
UPDATE ISSUED AT 638 AM CDT SAT AUG 22 2015
GIVEN SATELLITE AND RADAR TRENDS THROUGH 1130 UTC...THE 06 UTC
NAM AND NAM CONUS NEST...AND 09-10 UTC HRRR ITERATIONS...REDUCED
POPS FOR THIS MORNING INTO THE AFTERNOON SOUTH CENTRAL AND INTO
THE JAMES RIVER VALLEY IN ASSOCIATION WITH THE DRY SLOT.
HOWEVER...THESE AREAS ARE EXPECTED TO BE IMPACTED BY DEFORMATION
ZONE RAINFALL BY LATE AFTERNOON/EARLY EVENING AND INTO THE NIGHT.
NO CHANGES TO WIND HEADLINES AT THIS TIME. HOWEVER...THE 06 UTC
GFS/NAM 0.5 KM WIND FIELDS SUGGEST 50 KT OR GREATER GUSTS MAY BE
POSSIBLE ACROSS A WIDER PORTION OF THE AREA LATE THIS AFTERNOON
AND THROUGH THE EVENING. SHOULD THIS TREND CONTINUE...AN EXPANSION
OF THE HIGH WIND WARNING MAY BE NEEDED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SAT AUG 22 2015
CURRENT SURFACE ANALYSIS PLACES COLD FRONT WORKING ITS WAY INTO
THE WESTERN DAKOTAS. UPPER LEVEL ANALYSIS PLACES SOUTHWEST FLOW
OVER THE NORTHERN PLAINS WHILE TROF WORKS ITS WAY OUT OF THE
NORTHERN ROCKIES TOWARDS THE PLAINS. INITIAL WAVE LIFTING AHEAD OF
THE TROUGH CONTINUES TO PRODUCE SOME SHOWERS WITH A FEW
THUNDERSTORMS OVER WESTERN PORTIONS OF NORTH DAKOTA.
FOR TODAY...COLD FRONT WILL CONTINUE TO ADVANCE THROUGH THE AREA
WITH NORTHWEST WINDS INCREASING IN ITS WAKE. STRONGEST WINDS WILL
BE OVER SOUTHWEST NORTH DAKOTA WHERE GREATEST PRESSURE RISES ARE
EXPECTED BY AROUND MID-DAY. THE GUSTY WINDS WILL CONTINUE TO
SPREAD EASTERLY THROUGH CENTRAL NORTH DAKOTA BY LATE AFTERNOON.
PRECIPITATION WILL CONTINUE TO DEVELOP AND SPREAD THROUGH THE AREA
AS TROUGH MAKES ITS ADVANCE INTO THE AREA...WITH THE GREATEST
PRECIPITATION CHANCES/AMOUNTS EXPECTED TO BE OVER THE NORTHERN
PORTIONS OF THE STATE. WILL KEEP SOME MENTION OF THUNDER IN
THROUGH THE PERIOD...THOUGH EXPECT THE STRONGER STORMS TO REMAIN
TO THE EAST OF THE AREA WHERE GREATEST INSTABILITY IS NOTED AHEAD
OF THE FRONT.
FOR TONIGHT...WINDS ARE EXPECTED TO PEAK IN THE EARLY EVENING OVER
CENTRAL NORTH DAKOTA WHEN STRONGEST PRESSURE RISES FOR THAT AREA
MOVE THROUGH. LATEST FORECAST SOUNDINGS KEEP MIXING THE STRONGER
WINDS DOWN THROUGH THE EVENING HOURS SO HAVE EXTENDED THE TIMING
OF THE WIND ADVISORY OVER THAT AREA. OTHERWISE...PRECIPITATION
SHIELD WILL TRACK FROM WEST TO EAST WITH CONDITIONS STARTING TO
DRY OUT OVER THE WEST IN THE EVENING. A FEW CLAPS OF THUNDER WILL
REMAIN POSSIBLE IN THE EARLY EVENING...WITH ONLY SHOWERS EXPECTED
BY LATE EVENING/OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 315 AM CDT SAT AUG 22 2015
A RETURN TO NOMINAL LATE AUGUST SENSIBLE WEATHER HIGHLIGHTS THE
EXTENDED FORECAST.
GIVEN GOOD AGREEMENT AMONGST THE 00 UTC DETERMINISTIC AND ENSEMBLE
SUITES...WILL USE A BLEND FOR ALL FIELDS. OVERALL...AFTER A COOL
AND BREEZY SUNDAY IN THE WAKE OF THE STORM SYSTEM FROM THE SHORT
TERM...A RETURN TO RATHER NORMAL CONDITIONS ARE EXPECTED NEXT
WEEK AS AN INTERMOUNTAIN WEST RIDGE AMPLIFIES. HOWEVER...THE TREND
IN THE 00 UTC CONSENSUS IS FOR THE RIDGE AXIS TO A BIT FURTHER
WEST THAN PREVIOUS RUNS...RESULTING IN A COOLER...ALBEIT NEAR
NORMAL...FORECAST FOR TEMPERATURES FOR NEXT WEEK COMPARED TO
PREVIOUS FORECAST ITERATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 638 AM CDT SAT AUG 22 2015
A STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE DAKOTAS TODAY.
WIDESPREAD SHOWERS SPREADING NORTHWEST TO SOUTHEAST BRINGING MVFR
CEILINGS AND VISIBILITIES...LOWERING TO IFR BY THIS EVENING AND
INTO TONIGHT. VERY STRONG NORTHWEST WINDS OF 25 TO 35 KTS WITH
GUSTS OF 40-50KTS ARE ALSO EXPECTED TO DEVELOP FROM WEST TO EAST
TODAY INTO TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 1 AM
CDT /MIDNIGHT MDT/ SUNDAY FOR NDZ002>005-010>013-019>023-025-
034>037-042-045>048-050-051.
HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR NDZ031>033-040-
041-043-044.
WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR NDZ001-009-017-
018.
&&
$$
UPDATE...WAA
SHORT TERM...JJS
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
646 AM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 638 AM CDT SAT AUG 22 2015
GIVEN SATELLITE AND RADAR TRENDS THROUGH 1130 UTC...THE 06 UTC
NAM AND NAM CONUS NEST...AND 09-10 UTC HRRR ITERATIONS...REDUCED
POPS FOR THIS MORNING INTO THE AFTERNOON SOUTH CENTRAL AND INTO
THE JAMES RIVER VALLEY IN ASSOCIATION WITH THE DRY SLOT.
HOWEVER...THESE AREAS ARE EXPECTED TO BE IMPACTED BY DEFORMATION
ZONE RAINFALL BY LATE AFTERNOON/EARLY EVENING AND INTO THE NIGHT.
NO CHANGES TO WIND HEADLINES AT THIS TIME. HOWEVER...THE 06 UTC
GFS/NAM 0.5 KM WIND FIELDS SUGGEST 50 KT OR GREATER GUSTS MAY BE
POSSIBLE ACROSS A WIDER PORTION OF THE AREA LATE THIS AFTERNOON
AND THROUGH THE EVENING. SHOULD THIS TREND CONTINUE...AN EXPANSION
OF THE HIGH WIND WARNING MAY BE NEEDED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SAT AUG 22 2015
CURRENT SURFACE ANALYSIS PLACES COLD FRONT WORKING ITS WAY INTO
THE WESTERN DAKOTAS. UPPER LEVEL ANALYSIS PLACES SOUTHWEST FLOW
OVER THE NORTHERN PLAINS WHILE TROF WORKS ITS WAY OUT OF THE
NORTHERN ROCKIES TOWARDS THE PLAINS. INITIAL WAVE LIFTING AHEAD OF
THE TROUGH CONTINUES TO PRODUCE SOME SHOWERS WITH A FEW
THUNDERSTORMS OVER WESTERN PORTIONS OF NORTH DAKOTA.
FOR TODAY...COLD FRONT WILL CONTINUE TO ADVANCE THROUGH THE AREA
WITH NORTHWEST WINDS INCREASING IN ITS WAKE. STRONGEST WINDS WILL
BE OVER SOUTHWEST NORTH DAKOTA WHERE GREATEST PRESSURE RISES ARE
EXPECTED BY AROUND MID-DAY. THE GUSTY WINDS WILL CONTINUE TO
SPREAD EASTERLY THROUGH CENTRAL NORTH DAKOTA BY LATE AFTERNOON.
PRECIPITATION WILL CONTINUE TO DEVELOP AND SPREAD THROUGH THE AREA
AS TROUGH MAKES ITS ADVANCE INTO THE AREA...WITH THE GREATEST
PRECIPITATION CHANCES/AMOUNTS EXPECTED TO BE OVER THE NORTHERN
PORTIONS OF THE STATE. WILL KEEP SOME MENTION OF THUNDER IN
THROUGH THE PERIOD...THOUGH EXPECT THE STRONGER STORMS TO REMAIN
TO THE EAST OF THE AREA WHERE GREATEST INSTABILITY IS NOTED AHEAD
OF THE FRONT.
FOR TONIGHT...WINDS ARE EXPECTED TO PEAK IN THE EARLY EVENING OVER
CENTRAL NORTH DAKOTA WHEN STRONGEST PRESSURE RISES FOR THAT AREA
MOVE THROUGH. LATEST FORECAST SOUNDINGS KEEP MIXING THE STRONGER
WINDS DOWN THROUGH THE EVENING HOURS SO HAVE EXTENDED THE TIMING
OF THE WIND ADVISORY OVER THAT AREA. OTHERWISE...PRECIPITATION
SHIELD WILL TRACK FROM WEST TO EAST WITH CONDITIONS STARTING TO
DRY OUT OVER THE WEST IN THE EVENING. A FEW CLAPS OF THUNDER WILL
REMAIN POSSIBLE IN THE EARLY EVENING...WITH ONLY SHOWERS EXPECTED
BY LATE EVENING/OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 315 AM CDT SAT AUG 22 2015
A RETURN TO NOMINAL LATE AUGUST SENSIBLE WEATHER HIGHLIGHTS THE
EXTENDED FORECAST.
GIVEN GOOD AGREEMENT AMONGST THE 00 UTC DETERMINISTIC AND ENSEMBLE
SUITES...WILL USE A BLEND FOR ALL FIELDS. OVERALL...AFTER A COOL
AND BREEZY SUNDAY IN THE WAKE OF THE STORM SYSTEM FROM THE SHORT
TERM...A RETURN TO RATHER NORMAL CONDITIONS ARE EXPECTED NEXT
WEEK AS AN INTERMOUNTAIN WEST RIDGE AMPLIFIES. HOWEVER...THE TREND
IN THE 00 UTC CONSENSUS IS FOR THE RIDGE AXIS TO A BIT FURTHER
WEST THAN PREVIOUS RUNS...RESULTING IN A COOLER...ALBEIT NEAR
NORMAL...FORECAST FOR TEMPERATURES FOR NEXT WEEK COMPARED TO
PREVIOUS FORECAST ITERATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 638 AM CDT SAT AUG 22 2015
A STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS THE DAKOTAS TODAY.
WIDESPREAD SHOWERS SPREADING NORTHWEST TO SOUTHEAST BRINGING MVFR
CEILINGS AND VISIBILITIES...LOWERING TO IFR BY THIS EVENING AND
INTO TONIGHT. VERY STRONG NORTHWEST WINDS OF 25 TO 35 KTS WITH
GUSTS OF 40-50KTS ARE ALSO EXPECTED TO DEVELOP FROM WEST TO EAST
TODAY INTO TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 1 AM
CDT /MIDNIGHT MDT/ SUNDAY FOR NDZ002>005-010>013-019>023-025-
034>037-042-045>048-050-051.
HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR NDZ031>033-040-
041-043-044.
WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR NDZ001-009-017-
018.
&&
$$
UPDATE...AYD
SHORT TERM...JJS
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
204 PM MDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 913 AM MDT SAT AUG 22 2015
COLD FRONT IS A LITTLE AHEAD OF SCHEDULE AND ALREADY REACHING
THE NORTHERN BORDER AREA. THERE IS AN UNSEASONABLY STRONG PRESSURE
SURGE BEHIND THIS FRONT...BUT AT THE SAME TIME FRONT WILL BE
RUNNING INTO BETTER MIXING AND DAYTIME HEATING WHICH COULD ALLOW
FRONT TO WASH OUT A BIT. AS A RESULT...CHALLENGING WIND FORECAST
BETWEEN WEST/NORTHWEST OVER THE MOUNTAINS AND NORTH/NORTHEAST
ACROSS THE PLAINS. HRRR AND RAP MODELS APPEAR OVER MIXED AT THIS
POINT WHICH IS A TYPICAL BIAS...AND BELIEVE BASED ON REAL DATA
UPSTREAM THAT THE FRONT WILL HAVE ENOUGH STRENGTH TO BACK INTO/UP
AGAINST THE FRONT RANGE FOOTHILLS. MADE A FEW ADJUSTMENTS TO
TEMPS/DIURNAL TRENDS AND WINDS ON THE PLAINS BASED ON THESE
EXPECTATIONS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 300 AM MDT SAT AUG 22 2015
STRONG UPPER LEVEL TROF AND ASSOCIATED COLD FRONT WILL SWEEP
ACROSS THE NORTHERN HIGH PLAINS AND ROCKY MOUNTAIN REGION THIS
AFTERNOON. CURRENT COLD FRONTAL LOCATION IS ACROSS NORTHERN
WYOMING AND EXPECTED INTO FAR NORTHERN COLORADO BORDER AREAS BY
MID MORNING AND THEN INTO DENVER AREA AND POINTS SOUTH THIS
AFTERNOON. DECENT PRESSURE RISES WITH THIS FRONT AND WIND GUSTS IN
THE 25-40KT RANGE. WINDS WON`T BE QUITE THAT STRONG IN COLORADO
BUT CERTAINLY IN THE 15-30KT RANGE LOOKS REASONABLE AS BEST
PRESSURE RISES WILL SHIFT INTO NEBRASKA. THE BRUNT OF THE
MOISTURE AND LIFT WITH THIS TROF WILL REMAIN WELL NORTH AND EAST
OF COLORADO BUT THERE COULD BE SOME SHOWERS ACROSS THE PALMER
DIVIDE AND SOUTHERN PORTIONS OF CWA. BEHIND THE COLD FRONT...DRY
AND STABLE AIRMASS WILL MOVE IN WITH CLEARING SKIES TONIGHT AS
TEMPERATURES DROP INTO 40S AND LOWER 50S ACROSS THE PLAINS.
WITH THE UPPER TROF TRAJECTORY COULD ALSO CONTINUE TO SEE
SMOKE/HAZY CONDITIONS FROM FIRES ACROSS THE PACIFIC NORTHWEST.
SOME OBSERVATIONS SITES IN WYOMING AND SOUTH DAKOTA AND OBSERVING
SMOKE AND HAZE. CURRENT WEATHER GRIDS ALREADY HAVE THIS ADDRESSED
SO NO CHANGES NEEDED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 AM MDT SAT AUG 22 2015
AN UNSEASONABLY STRONG UPPER TROUGH MOVING ALONG THE U.S./CANADIAN
BORDER SWEEPS OUT OVER THE NORTHERN GREAT PLAINS ON SUNDAY AS THE
FLATTENED UPPER RIDGE OVER THE 4-CORNERS REGION REGAINS SOME
AMPLITUDE. THIS KEEPS THE FORECAST AREA UNDER THE INFLUENCE OF A
GENERALLY DRY NORTHWEST FLOW...AND WITH THIS FLOW REACHING UP OVER
THE PACIFIC NORTHWEST...WE COULD CONTINUE TO SEE HAZY SKIES AROUND
HERE BUT PERHAPS LESS OPAQUE AS THE LOW-LEVEL FLOW IS FORECAST TO
SHIFT TO A LESS SMOKEY S-SWLY COMPONENT IN THE AFTERNOON. SUCH A
FLOW WILL AID IN WARMING THE POST-FRONTAL AIRMASS PARTICULARLY ON
THE PALMER DIVIDE AND SOUTHERN PORTIONS OF THE I-25 URBAN CORRIDOR
INCLUDING THE GREATER DENVER METRO AREA WHERE HIGH TEMPERATURES WILL
BE NEAR AVERAGE FOR THE DATE. FARTHER OUT ON THE PLAINS SEE LITTLE
CHANGE IN TEMPERATURE FROM THE DAY BEFORE WITH HIGHS SEVERAL DEGS
BELOW AVERAGE. FROM AFTERNOON INTO THE OVERNIGHT HOURS MODELS SHOW
FURTHER STRENGTHENING OF THE UPPER RIDGE AND AS BUILDS NORTHWARD SO
WILL MID/HIGH-LEVEL MOISTURE. COULD SEE A FEW LIGHT RAIN SHOWERS/T-
STORMS PRODUCING GUSTY WINDS OVER THE HIGH TERRAIN ACRS SWRN
SECTIONS OF THE CWA BY EVENING. OTHERWISE DRY CONDITIONS WILL
PREVAIL.
ON MONDAY...FURTHER AMPLIFICATION OF THE UPPER RIDGE AND A SLIGHT
EASTWARD SHIFT SHOULD BEGIN TO DIVERT MORE OF THE SMOKE FROM PAC
NORTHWEST WILDFIRES AWAY FROM THE FRONT RANGE. HOWEVER IT MAY BE
LESS APPARENT AS SKIES WILL LIKELY CONTAIN MORE CLOUDS AS
SUBTROPICAL MOISTURE FLOWS UP FROM THE 4-CORNERS REGION. NOT LOOKING
FOR A BUNCH OF CLOUDS AND THE CHANCE FOR MEASURABLE PRECIP SHOULD
REMAIN LOW ESPLY EAST OF THE MTNS. WARMING ALOFT SHOULD CAP T-STORM
DEVELOPMENT ON THE PLAINS. THIS SAME WARMING ALOFT WILL BE REFLECTED
AT THE SURFACE BY HIGH TEMPERATURES 4-7 DEG F WARMER THAN THE DAY
BEFORE. THE BIGGEST CHANGE IN TEMPERATURE WILL OCCUR ACRS THE NERN
CORNER OF THE CWA WHERE CLOUD COVER LESS EVIDENT.
FOR TUESDAY AND WEDNESDAY...MODELS SHOW THE UPPER RIDGE CONTINUING
TO MIGRATE EAST WHICH OPENS UP THE REGION TO INCREASINGLY MOIST SWLY
FLOW. AREAS EAST OF THE MTNS SHOULD NOT SEE MUCH IMPACT FROM THIS
INFLUX OF MOISTURE OTHER THAN MORE AFTERNOON/EVENING CLOUD COVER AND
PERHAPS A SLIGHTLY BETTER CHANCE OF LATE DAY T-STORMS MAINLY ALONG
THE FRONT RANGE. MTN AREAS WILL HAVE A BETTER CHANCE FOR T-STORMS
DURING THE PERIOD ESPLY WEDNESDAY WHEN MODELS SHOW A WEAK UPPER AIR
DISTURBANCE PASSING OVER THE AREA. WILL STICK WITH PRECIP CHANCES IN
THE 30-50 PCT RANGE IN THE HIGH COUNTRY WITH 10-20 PCT AT LOWER
ELEVATIONS. TEMPERATURES BOTH DAYS LITTLE CHANGED FROM MONDAY AND
STILL SLIGHTLY ABOVE AVERAGE FOR THE DATE.
THURSDAY AND FRIDAY...MEDIUM RANGE MODELS AGREE IN RETROGRADING THE
UPPER RIDGE AS THE UPPER AIR DISTURBANCE SLOWLY DROPS SEWRD OVER
NERN COLORADO DURING THE DAY THURSDAY. LEADING THE DISTURBANCE WILL
BE A WEAK COLD FRONT WHICH FIRST USHER DRY AIR DOWN FROM WY ON NWLY
WINDS THEN SHIFTS TO AN UPSLOPE FLOW WHICH MAY STIMULATE T-STORM
FORMATION OVER AND ALONG THE FRONT RANGE BY THE AFTERNOON AS THE
UPPER AIR DISTURBANCE PASSES BY. BY FRIDAY COULD SEE THE UPPER RIDGE
BUILDING BACK OVER THE STATE AND AS IT DOES RETURNING THE AREA TO
NWLY FLOW ALOFT. THIS COULD AGAIN BLOW IN MORE SMOKE FROM THE
PACIFIC NW WILDFIRES. OTHERWISE FRIDAY SHOULD BE THE DRIER DAY...
WITH TEMPERATURES BOTH DAYS NEAR AVERAGE.
&&
.AVIATION...(FOR THE TAFS THROUGH 00Z SUNDAY LATE AFTERNOON)
ISSUED AT 200 PM MDT SAT AUG 22 2015
ISOLATED SHOWERS AND THUNDERSTORMS WERE JUST A BIT FARTHER NORTH
THAN ANTICIPATED SO WILL SEE A LOW THREAT OF THUNDER IN THE DENVER
AREA AIRPORTS TIL 23Z...BUT MOSTLY LIGHT RAIN SHOWERS. OTHERWISE
HAZE/SMOKE IS REDUCING VSBY TO AROUND 5SM AND THIS SHOULD PERSIST
THROUGH THE EVENING.
&&
.FIRE WEATHER...
ISSUED AT 913 AM MDT SAT AUG 22 2015
THERE WILL STILL BE A NARROW CORRIDOR OF VERY WARM AND DRY AIR
LOCATED OVER THE MOUNTAINS AND HIGH VALLEYS OF NORTH CENTRAL
COLORADO TODAY. UPSTREAM RIVERTON AND GRAND JUNCTION SOUNDINGS
SHOWED A DRY AIRMASS AND SUFFICIENT WINDS ALOFT. DAYTIME HEATING
AND MIXING WILL LEAD TO INCREASING WINDS AND RED FLAG CONDITIONS
IN ZONES 211...213...217...AND 218 THROUGH MUCH OF THE AFTERNOON
WHERE FUELS ARE DRIEST. HAVE ISSUED A RED FLAG WARNING FOR THOSE
LOCATIONS...BUT CONDITIONS WILL IMPROVE BY 6 TO 7 PM AT THE
LATEST. COLD FRONT MOVING ACROSS THE PLAINS AND SHOULD BACK INTO
THE LOWER FOOTHILLS THROUGH THE AFTERNOON. ZONES 215 AND 216
MARGINAL FOR RED FLAG CONDITIONS BUT STILL SOME THREAT THERE BUT
MAINLY OVER EXPOSED HIGHER RIDGES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR COZ211-213-217-
218.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...ENTREKIN
LONG TERM...BAKER
AVIATION...BARJENBRUCH
FIRE WEATHER...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
318 PM EDT SAT AUG 22 2015
.SHORT TERM (TONIGHT-MON NIGHT)...
SURFACE HIGH PRESSURE REMAINS OVER THE CENTRAL AND WESTERN GULF
THROUGH THE WEEKEND, WITH SURFACE LOW PRESSURE/TROUGH EXTENDING
THROUGH THE WESTERN ATLANTIC AND OFF THE SE CONUS COAST. THIS
PATTERN WILL KEEP A NORTHEASTERLY COMPONENT IN THE WIND PROFILE,
BECOMING SOMEWHAT STRONGER INTO SUNDAY, AS A WEAK SHRTWV DIVES
SOUTH THROUGH OUR ATLANTIC WATERS TONIGHT.
FOR THIS AFTERNOON AND EVENING...H5 TEMPS HAVE WARMED 1.5C COMPARED
TO YESTERDAY`S 12Z RAOB. STORM MOTION CONTINUES TO BE SLOW FROM
THE NNE TO NE. THIS MAY ALLOW A FEW SHWS OR STORMS TO FORM IN THE
WESTERN SUBURBS, BUT THE FOCUS SHOULD AGAIN BE THE INTERIOR AND
THEN WEST COAST LATE DAY. PERHAPS A STRONGER WIND GUST BUT
SOUNDING PARAMETERS ARE NOT CONDUCIVE FOR STRONG STORMS TODAY.
ACTIVITY WANES AS USUAL THIS EVENING, BUT HRRR SHOWING SOME
DEVELOPMENT IN THE ATLANTIC WATERS AS THE WEAK DISTURBANCES DIVES
SOUTH TONIGHT. THIS COULD PUT A FEW SHWS OR STORMS ALONG THE
MIAMI-DADE/BROWARD COAST INTO TOMORROW MORNING.
SUNDAY...PERHAPS MORE OF A FOCUS ON THE SOUTHERN INTERIOR AND NOT AS
MUCH COVERAGE ON THE WEST COAST AS THE PAST FEW DAYS, WITH THE
STRONGER NORTHEASTERLY COMPONENT IN THE STORM MOTION, PERHAPS ENOUGH
TO PREVENT THE DURATION AND STRENGTH OF THE GULF BREEZE. BETTER
COVERAGE OF MORNING SHOWERS OR STORMS ALONG THE EAST COAST WITH
THE SRTWV OFFSHORE.
MONDAY...H5 CLOSED HIGH PRESSURE CURRENTLY OVER THE GULF OF MEXICO
RETROGRADES TO TEXAS AND THEN THE FOUR CORNERS REGION. SURFACE
TROUGH BEGINS BUILDING SOUTH ALONG THE EASTERN SEABOARD, ALTHOUGH
SURFACE HIGH PRESSURE AXIS BEGINS TO STRETCH ACROSS THE BAHAMAS
AGAIN, WHICH ADDS MORE EASTERLY COMPONENT TO THE SURFACE FLOW. OP
GFS POPS LOOK SUSPICIOUSLY LOW ACROSS THE INTERIOR WHICH IS
AFFECTING THE BLENDS, SO WILL ADJUST UPWARD. HOWEVER PWATS ARE
FORECAST TO DROP THIS DAY. H5 TEMPS AND H7-H5 LAPSE RATES STILL
UNIMPRESSIVE.
.LONG TERM (TUES-SAT)...
MID AND UPPER TROUGH TAKES OVER MUCH OF THE EASTERN CONUS THROUGH
THE PERIOD. SURFACE LOW PRESSURE WILL DEVELOP OVER NE FL OR SE GA
WED AND THURS. IN RESPONSE, H5 TEMPS WILL COOL AND H7-H5 LAPSE RATES
WILL BECOME MORE FAVORABLE. SO STORMS WILL BE STRONGER THAN WHAT
WE`VE EXPERIENCED THIS PAST WEEK. HOWEVER, SURFACE HIGH PRESSURE
WILL HOLD ON ACROSS THE WESTERN ATLANTIC AND THE BAHAMAS FOR A
WHILE, SUCH THAT SURFACE FLOW DOES NOT VEER TO THE SW UNTIL LATE
WEEK, AND THEN PERHAPS ONLY BRIEFLY.
NHC CONTINUES TO WEAKEN HURRICANE DANNY IN THEIR CURRENT FORECAST
INTO THE MIDDLE OF THE WEEK. HOWEVER, WE STILL NEED TO CONTINUE
TO MONITOR DANNY`S PROGRESS AND LATEST FORECASTS.
&&
.AVIATION...
WITH LIMITED INSTABILITY, CONVECTION IS HAVING A HARD TIME
GETTING GOING THIS AFTERNOON. THE HRRR STILL SHOWING SHOWERS AND
THUNDERSTORMS DEVELOPING THIS AFTERNOON. BUT, HAS BEEN OVERDOING
IT SO FAR. HAVE KEPT VCTS IN MOST TAFS, BUT AND CONVECTION WILL
LIKELY BE IN THE INTERIOR. SO, MOSTLY VFR THROUGH THE TAF PERIOD,
WITH WINDS BECOMING LIGHT AND VARIABLE TONIGHT, AS WELL AS SKIES
CLEARING LATER THIS EVENING.
&&
.MARINE...
A NORTHEASTERLY WIND WILL PREVAIL THROUGH MONDAY WITH SPEEDS
AVERAGING 10 KT OR LESS. SEAS WILL BUILD SLIGHTLY, BUT STILL BE LESS
THAN 4 FT. WINDS WILL VEER MORE TO THE EAST INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 80 92 78 92 / 40 30 10 20
FORT LAUDERDALE 80 91 80 91 / 50 40 10 20
MIAMI 79 93 79 91 / 40 50 20 20
NAPLES 78 93 78 92 / 40 40 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...21/KM
LONG TERM....21/KM
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
157 PM EDT SAT AUG 22 2015
.AVIATION...
WITH LIMITED INSTABILITY, CONVECTION IS HAVING A HARD TIME
GETTING GOING THIS AFTERNOON. THE HRRR STILL SHOWING SHOWERS AND
THUNDERSTORMS DEVELOPING THIS AFTERNOON. BUT, HAS BEEN OVERDOING
IT SO FAR. HAVE KEPT VCTS IN MOST TAFS, BUT AND CONVECTION WILL
LIKELY BE IN THE INTERIOR. SO, MOSTLY VFR THROUGH THE TAF PERIOD,
WITH WINDS BECOMING LIGHT AND VARIABLE TONIGHT, AS WELL AS SKIES
CLEARING LATER THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 1036 AM EDT SAT AUG 22 2015/
UPDATE...
NO MAJOR CHANGES FOR THIS UPDATE. TWEAKED POPS FOR THIS MORNING TO
BETTER REFLECT WHAT IS CURRENT SHOWING ON RADAR. THE HRRR IS
STILL SHOWING SOME THUNDERSTORM ACTIVITY THIS AFTERNOON. THIS
MORNINGS SOUNDING DOES SHOW WARM TEMPERATURE OF -4.9C AT 500MB.
ALSO, THE FREEZING LEVEL IS OVER 16000FT. THE NCAPE IS .14,
INDICATING STORMS LIFE MAY BE A COMBINATION OF SOME PULSE TYPE
STORMS, AND A FEW CELLS THAT HAVE A SOMEWHAT LONGER LIFE SPAN. THE
PWATS ARE JUST OVER 2 INCHES, WHICH MEANS, TYPICAL HEAVY RAIN.
HOWEVER, THE STORM MOTION WILL FAIRLY SLOW, BEING LESS THAN 10KTS.
HOWEVER, MOST OF THE ACTIVITY SHOULD BE IN THE INTERIOR, SO ANY
URBAN FLOODING, EVEN MINOR, LOOKS TO BE AT A VERY LOW RISK. BUT,
IF STORMS DO DEVELOP A LITTLE FURTHER EAST, IT COULD LEAD TO
PONDING OF WATER ON ROADWAYS AND POOR DRAINAGE AREAS. OTHERWISE,
LOOKING AT TYPICAL GARDEN VARIETY THUNDERSTORMS, WITH AN ISOLATED
STRONG STORM POSSIBLE.
PREV DISCUSSION... /ISSUED 752 AM EDT SAT AUG 22 2015/
AVIATION...
HIGH PRESSURE, TO THE NORTHWEST, WILL KEEP THE WIND OUT OF THE NORTH
TO NORTHEAST TODAY. THE ATLANTIC SEA BREEZE WILL DEVELOP IN THE
EARLY AFTERNOON. THIS WILL HELP TO CAUSE THUNDERSTORMS TO DEVELOP.
MOST OF THE STORMS SHOULD BE WEST OF THE TAF SITES, ALTHOUGH THERE
IS STILL A CHANCE OVER THE AIRPORTS,, SO HAVE A VCTS IN THE TAFS
FOR THE AFTERNOON AND EVENING HOURS. VFR CONDITIONS ARE EXPECTED
THROUGH THE TAF PERIOD, WITH BRIEF IFR UNDER HEAVY RAIN AND
THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 325 AM EDT SAT AUG 22 2015/
DISCUSSION...
RIDGE OF HIGH PRESSURE OVER THE EASTERN GULF AND FLORIDA WILL
DOMINATE THE REGION THROUGH SUNDAY. THIS WILL FOCUS AFTERNOON
CONVECTION ACROSS THE INTERIOR AND GULF COAST. ISOLATED MORNING
TSTORMS ARE POSSIBLE ACROSS THE EAST COAST METRO. THE MAIN TSTORM
IMPACTS WILL BE LIGHTNING STRIKES AND HEAVY DOWNPOURS.
WINDS THIS MORNING ARE OFFSHORE OUT OF THE NW AND LIGHT ACROSS THE
EAST COAST METRO AND NEAR SHORE ATLANTIC WATERS. AS CUMULUS
DEVELOPS THIS MORNING...THIS OFFSHORE WIND FLOW CONVERGING ONTO
THE SYNOPTIC ENE WIND FLOW...COULD RESULT IN A FEW WATERSPOUTS
FORMING OVER THE ATLANTIC AND BISCAYNE BAY THIS MORNING.
INTERESTINGLY...NRL/NAVY AEROSOL MODEL SHOWS THAT SKIES COULD
BECOME SOMEWHAT HAZY ACROSS SOUTH FL TODAY AND INTO EARLY NEXT
WEEK...BUT NOT FROM SAHARAN DUST, RATHER SULFATE/POLLUTANTS FROM
THE MAINLAND/DEEP SOUTH SPREADING SOUTH DOWN THE PENINSULA.
THE AFOREMENTIONED RIDGE WILL BE REPLACED BY A TROUGH DIGGING
INTO THE EASTERN SEABOARD EARLY-MID NEXT WEEK. THIS WILL RESULT
IN A MORE SW STEERING WIND ALBEIT RATHER LIGHT. FOLLOWED A CLIMO
PATTERN OF DIURNAL CONVECTION EACH DAY WITH FOCUS OVER THE
INTERIOR EACH DAY. GFS IS MORE AMPLIFIED LATE NEXT WEEK WHILE
ECMWF NUDGES IN A RIDGE...SO FLOW PATTERN IS MORE UNCERTAIN THEN.
HURRICANE DANNY IS FORECAST TO CONTINUE TO WEAKEN AS IT HAS DRY
AIR, WIND SHEAR, AND POSSIBLY LAND INTERACTION AHEAD OF IT. GLOBAL
MODELS DEGENERATE DANNY INTO AN OPEN WAVE. WE WILL CONTINUE TO
MONITOR DANNY`S PROGRESS, BUT FOR NOW A CLIMO FORECAST NEXT WEEK
IS LOOKING PRUDENT. /GREGORIA
MARINE...
A NORTHEASTERLY WIND WILL PREVAIL INTO EARLY NEXT WEEK WITH SPEEDS
AVERAGING 10 KT OR LESS. SEAS WILL BUILD SLIGHTLY...BUT STILL BE
LESS THAN 4 FT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 80 92 78 91 / 20 30 10 20
FORT LAUDERDALE 80 91 80 90 / 20 40 20 20
MIAMI 80 93 79 92 / 20 50 30 30
NAPLES 79 92 77 91 / 40 30 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...13/SI
LONG TERM....60/BD
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
403 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 /20Z SATURDAY THROUGH THURSDAY/...
CONVECTION APPEARS TO BE DONE AT KCHS BUT THERE IS INCREASING
CONFIDENCE IN SHOWERS AND TSTMS MOVING THROUGH THE KSAV TERMINAL
BETWEEN 21-00Z. AT THIS POINT WE MAINTAINED VICINITY TSRA BUT MAY
EVENTUALLY NEED TO AMEND TO INCLUDE PREVAILING TSRA. CONVECTION
SHOULD BE OUT OF THE AREA BY EARLY EVENING. THEN 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 LIKELY HAVE WET SOIL...FOG MAY VERY WELL SPREAD FARTHER
SOUTHEAST AND DROP VSBYS AT ONE OR BOTH TERMINALS INTO MVFR OR
LOWER. LATER SHIFTS WILL NEED TO REASSESS.
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...JRL/RJB
MARINE...JRL/RJB
AREA FORECAST DISCUSSION
NWS LINCOLN IL
100 PM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 1045 AM CDT SAT AUG 22 2015
WILL NEED TO UPDATE THE FORECAST TO INCREASE CHANCES OF SHOWERS
AND POSSIBLE THUNDERSTORMS IN OUR SW COUNTIES FROM SPRINGFIELD
LATE THIS MORNING AND EARLY AFTERNOON. ALSO INCREASED CLOUD COVER
INTO EARLY AFTERNOON ESPECIALLY SW OF I-74. SHOWERS WERE AS FAR NE
AS SCOTT AND MORGAN COUNTIES AT 1040 AM WITH THUNDERSTORMS AROUND
ST LOUIS. THIS CONVECTION WAS DRIFTING NE AND WEAKENING AND SHOULD
CONTINUE TO WEAKEN NEXT FEW HOURS AS IT MOVES ACROSS OUR SW THIRD
OF CWA. MOST OF THIS CONVECTION SHOULD DISSIPATE BY MID AFTERNOON
WITH CLOUDS BREAK UP DURING THE MID/LATE AFTERNOON. HIGHS IN THE
LOW TO MID 80S THIS AFTERNOON.
&&
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
MOST OF OUR AREA STILL UNDER THE INFLUENCE OF HIGH PRESSURE WHICH
HAS SHIFTED INTO SOUTHEAST OHIO EARLY THIS MORNING. MEANWHILE TO
OUR SOUTHWEST...A WEAK SHORTWAVE WAS TRACKING EAST ACROSS WESTERN
MISSOURI WITH SHORT TERM MODELS CONTINUING TO SUGGEST SHOWERS AND
STORMS WILL EXPAND IN COVERAGE EARLY THIS MORNING AS THE UPPER LEVEL
WAVE TRACKS EAST. HOWEVER...BOTH THE RAP-13 AND HRRR MODELS HAVE
OVERDONE THE PRECIP ACROSS SOUTHWEST MISSOURI EARLY THIS
MORNING...ESPECIALLY COMPARED TO WHAT IS ACTUALLY OCCURRING NOW.
FORECAST SOUNDINGS INDICATE A BIT MORE CLOUD COVER OVER OUR WEST AND
SOUTHWEST COUNTIES AHEAD OF THE AFOREMENTIONED WAVE TODAY WITH SOME
850 MB MOISTURE CONVERGENCE SEEN ON THE MODELS THIS MORNING OVER
PARTS OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...ESPECIALLY LATE
THIS MORNING...TOWARDS 18Z. HAVE ADDED SOME SLIGHT CHANCE POPS OVER
FAR WEST AND SOUTHWEST IL FOR THIS MORNING INTO EARLY THIS AFTERNOON
JUST AHEAD OF THE WEAKENING UPPER WAVE. FURTHER EAST AND NORTH...
LESS CLOUD COVER SHOULD ALLOW AFTERNOON TEMPS TO RISE INTO THE LOW
TO MID 80S BASED OFF THE RAP SOUNDINGS.
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 22 2015
RAIN CHANCES INCREASING OVERNIGHT AND INTO TOMORROW AS A COLD FRONT
APPROACHES THE FORECAST AREA. PASSAGE OF THE COLD FRONT EXPECTED IN
THE EARLY MORNING HOURS THROUGH MIDDAY. WITH A LACK OF DIURNAL
HEATING IN THE AIRMASS OUT AHEAD OF THE BOUNDARY, HAVE PULLED THE
MAX TEMPS DOWN A COUPLE DEGREES. SOUTHEAST MAY REMAIN SOMEWHAT
WARMER FOR SUNDAYS HIGHS AND ILX WILL LIKELY HAVE QUITE A GRADIENT
OVER THE REGION. WITH THE GENERAL EARLINESS OF THE SYSTEM, LITTLE TO
NO SEVERE WEATHER IS EXPECTED. BEHIND THE COLD FRONT, HIGH PRESSURE
BUILDS BACK IN AT THE SURFACE. IN THE COOLER AIRMASS, THE TEMPS WILL
REMAIN SLIGHTLY BELOW NORMAL THROUGH MIDWEEK...BUT TRENDING WARMER.
THE WARM TREND WILL BE ENHANCED EVEN FURTHER AS THE HIGH PRESSURE
RIDGE AXIS SLIPS OFF TO THE EAST AND THE SFC WINDS BECOME MORE
SOUTHERLY AHEAD OF THE NEXT FRONT. AT THIS POINT, SOLUTIONS ARE NOT
CONSISTENT IN THE MODELS AND THE SUPERBLEND IS AN AMALGAM OF BOTH
THE WETTER SOLUTION AND THE MORE SPARSE WITH THE QPF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1259 PM CDT SAT AUG 22 2015
SPI JUST HAD SPRINKLES PAST HOUR AS MAIN AREA OF SHOWERS AND
THUNDERSTORMS PASSING SOUTH OF SPI/DEC EARLY THIS AFTERNOON AS IT
IS PROJECTED TO WEAKEN ON EASTWARD TRACK. CEILINGS COULD LOWER TO
3-5K FT AT TIMES THIS AFTERNOON ESPECIALLY AT SPI AND DEC WITH
BROKEN VEIL OF MID/HIGH CLOUDS. A COLD FRONT OVER EASTERN DAKOTAS
INTO CENTRAL NEBRASKA TO TRACK EAST ACROSS CENTRAL IL DURING
SUNDAY MORNING. THERE IS A CHANCE OF SHOWERS AND ISOLATED
THUNDERSTORMS LATER TONIGHT INTO MID MORNING SUNDAY WITH BEST
CHANCES OF THUNDERSTORMS AT PIA FROM 09-12Z. SSE WINDS AROUND 10
KTS WITH GUSTS 14-18 KTS THIS AFTERNOON TO LIGHTEN UP THIS EVENING
AFTER SUNSET AND THEN TURN WNW 10-15 KTS BEHIND COLD FRONT BETWEEN
14-17Z SUNDAY MORNING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...07
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...07
AREA FORECAST DISCUSSION
NWS DES MOINES IA
110 PM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 108 PM CDT SAT AUG 22 2015
SEVERE WEATHER POTENTIAL REMAINS ON TRACK FOR LATER TODAY AND
TONIGHT. SFC COLD FRONT IS MOVING THROUGH THE EASTERN DAKOTAS AND
NEBRASKA EARLY THIS AFTERNOON. LATEST VISIBLE SATELLITE IMAGERY
SHOWS SOME AGITATE CUMULUS ALONG AND AHEAD OF THE BOUNDARY HOWEVER
THE AIRMASS REMAINS CAPPED THROUGH THE AREA. A VIGOROUS SHORT WAVE
IS TRAILING OVER TO THE WEST AND SHOULD CATCH UP TO THE BOUNDARY
BY MID TO LATE AFTERNOON. THIS SYSTEM HAS AN ASSOCIATED 90 KT
UPPER LEVEL JET AND COMBINED...WILL BRING STRONG QG FORCING AND
UPPER LEVEL DIVERGENCE ALONG WITH COOLING MID LEVELS THAT WILL
ERODE THE CAP AND FORCE ASCENT. IN ADDITION...INCREASING LOW TO
UPPER LEVEL SHEAR WILL OCCUR DURING THIS TIME SUPPORTING STRONG
ORGANIZED UPDRAFTS SUPPORTIVE OF SUPERCELLS INITIALLY AND BRING AN
INCREASING TORNADO THREAT. THE STORMS SHOULD EVOLVE INTO QLCS
LINEAR SYSTEM AS IT MOVES INTO CENTRAL IOWA. THE SYSTEM SHOULD
MAINTAIN AN ATTENDANT TORNADO THREAT WITH ESRH VALUES AT 200-300
M2/S2 AND 0-3 KM LINE NORMAL SHEAR NEAR 30KTS. DAMAGING WINDS TO
70 MPH WILL ALSO BE POSSIBLE ALONG WITH LARGE HAIL. TIMING
WISE...EXPECT THUNDERSTORMS TO DEVELOP OVER WESTERN IOWA ROUGHLY
4-5 PM THEN SPREAD EASTWARD THROUGH THE EVENING AND REACHING DSM
METRO IN THE 7-9 PM TIME WINDOW THEN TOWARDS THE EAST 9 PM-
MIDNIGHT.
&&
.SHORT TERM /TODAY/...
ISSUED AT 327 AM CDT SAT AUG 22 2015
A VERY POTENT 500MB TROUGH WILL CONTINUE TO DEEPEN THROUGHOUT THE
DAY AS EJECTS OUT OF THE NORTHERN ROCKIES INTO THE DAKOTAS THIS
AFTERNOON. THE SURFACE LOW LOOKS TO DEVELOP AND STRENGTHEN OVER
THE EASTERN PORTIONS OF THE DAKOTAS WITH A SHARP COLD FRONT
EXTENDING SOUTHWARD INTO NEBRASKA BY MIDDAY TODAY AND THEN
TRANSITION SOUTHEAST INTO NORTHWEST IOWA LATE IN THE PERIOD.
TROUGH BECOMES NEGATIVELY TILTED BY AROUND 00Z SUNDAY. THERE IS A
LOW POTENTIAL FOR SOME ELEVATED STORMS TO TRY AND DEVELOP OVER
WESTERN TO NORTHWEST PORTIONS OF IOWA AHEAD OF THE COLD
FRONT...BUT WITH A VERY STRONG CAP IN PLACE...HAVE LOW CONFIDENCE
WITH ANYTHING WIDESPREAD AND THUS ANY SEVERE WX PRIOR TO THE FROPA
AND LEFT FORECAST DRY UNTIL 21Z.
THE HIRES 22.00Z ARW/NMM...22.00Z NSSL-WRF...22.05Z HRRR AND
COUPLE MEMBERS OF THE 22.03Z HOPWRF ALL SUGGEST CONVECTIVE
INITIATION B/T 21-23Z OVER FAR NORTHWEST IOWA. ACROSS THE WEST TO
NORTHWEST SECTIONS OF THE FORECAST AREA...DEEP LAYER SHEAR
INCREASES TO 40-45 KNOTS PAST 21Z WITH 0-1KM AND 0-3KM SHEAR BOTH
IN THE 20-30 KNOT RANGE. STRONG SURFACE BASE CAPE INCREASES TO
3000-3800 J/KG WITH STEEP LAPSE RATES IN THE 7.5-8 C/KM RANGE. LCL
HEIGHTS AROUND 600M IN THE WARM SECTOR AND EXPECTING DISCRETE
SUPERCELLS WITH INITIATION THIS AFTERNOON. HOWEVER...THE MOST
LIKELY SCENARIO IS STORMS LOOK TO QUICKLY EVOLVE INTO QLCS SQUALL
LINE BY TIME THEY MOVE INTO THE FORECAST AREA. THERE IS A
POTENTIAL FOR SUPERCELLS TO CREEP INTO THE FAR WESTERN TO
NORTHWESTERN EDGES OF THE FORECAST AREA (DENISON TO ESTHERVILLE
LINE) PRIOR TO THE SQUALL LINE EVOLUTION...AND HAVE POPS
INTRODUCED BY 21Z. ALL MODES OF SEVERE WEATHER POSSIBLE LATE THIS
AFTERNOON...WITH TORNADIC AND LARGE HAIL POTENTIAL UPON INITIATION
AND THEN MORE LIKELY DAMAGING WINDS WITH THE SUPERCELLS EVOLVING
INTO QLCS. CERTAINLY CANNOT RULE TORNADIC POTENTIAL WITHIN THE
QLCS LATE IN THE PERIOD. REGARDLESS...HAVE SEVERE MENTIONED PAST
21Z IN THE FAR NORTHWEST TO COINCIDE WITH SPC ENHANCED RISK AREA.
.LONG TERM /TONIGHT THROUGH FRIDAY/...
ISSUED AT 327 AM CDT SAT AUG 22 2015
ONGOING SEVERE WEATHER AND HEAVY RAINFALL EXPECTED EARLY IN THE
FIRST PERIOD. SEVERAL FACTORS POINT TO A ROBUST LINE OF CONVECTION
THIS EVENING. A STRONG COLD FRONT WITH IMPRESSIVE SFC
CONVERGENCE ...STRONG INSTABILITY/HIGH PRECIPITABLE WATER AND
APPROACHING H500 WAVE WILL COMBINE TO ENHANCE CONVECTION THROUGH
AT LEAST 06Z. MAIN CONCERNS AFTER 02Z WILL BE THREAT FOR WIND/HAIL
AND HEAVY RAINFALL. GFS BUFR SOUNDINGS AT 00Z SHOW 0-3KM SRH ABOUT
200-300 J/KG AT KDSM AS THE LINE REACHES CENTRAL IA AT THAT TIME
WITH STORM RELATIVE HELICITY WEAKENING TOWARD 06Z IN THE
SOUTHEAST. SBCAPE IS PROGGED TO BE 2750 WITH LCL OF NEAR
692M/2000FT. INITIALLY THE THREAT THROUGH ABOUT I35 WILL STILL
INCLUDE THE RISK OF A TORNADO THOUGH ANY DISCRETE SUPERCELLS IN
THE LATE AFTERNOON SHOULD BE EVOLVING INTO A MORE LINEAR AND
ACCELERATING LINE OF STORMS AS IT MOVES MORE RAPIDLY SOUTHEAST
WITH TIME. THROUGH THE EVENING HOURS THE THREAT FOR SEVERE WEATHER
WILL GRADUALLY WEAKEN AS BOTH CAPE AND HELICITY BEGIN TO LESSEN
WITH TIME. THE OTHER CONCERN WITH THIS EVENT WILL BE BRIEF BUT
VERY HEAVY RAINFALL. SUBJECTIVE 00Z SATURDAY H850 ANALYSIS THIS
EVENING SHOWS A +15C PLUME OF MOISTURE FROM THE TEXAS COAST UP
INTO CENTRAL/WESTERN NEBRASKA. THE GFS IS FORECASTING PRECIPITABLE
WATER OF UP TO 1.7 INCHES ALONG THE BOUNDARY IN WESTERN IA AT
18Z...AND A MORE BROAD AREA OF 1.75 TO AROUND 2 INCHES FROM
CENTRAL THROUGH SOUTHEAST IA FROM 00-06Z TONIGHT. THIS COMBINED
WITH AN EXPECTED WARM CLOUD DEPTH OF 3600-3800M (>12KFT) OVER
WESTERN IOWA...INCREASING TO OVER 4000M (>13KFT) FROM TAMA TO
DECATUR COUNTY BY 06Z WILL PROMOTE INCREASINGLY EFFICIENT RAINFALL
AS THE LINE BECOMES MORE ORGANIZED AND 0-6KM BULK SHEAR 50-60KTS
BEHIND THE BOUNDARY CATCHES UP TO THE LINE FROM 03-06Z. NMM
MOISTURE CONVERGENCE AND MOISTURE TRANSPORT VECTORS ARE BOTH
MAXIMIZED AT THIS TIME OVER CENTRAL/SOUTHERN IOWA. FOR NOW AM
ANTICIPATING AT LEAST A PERIOD OF 1-2 HOURS OF 1-2 INCH
RAINFALL/HOUR MAINLY FROM 03-06Z FROM NEAR AMES SOUTHWEST TO
CRESTON/LAMONI OR GENERALLY SOUTH OF HIGHWAY 30 AND ALONG AND WEST
OF I35. CURRENT 1HR GRIDDED FLASH FLOOD GUIDANCE IS RUNNING ABOUT
1.75 TO NEARLY 2 INCHES OVER MOST OF THIS REGION AND HIGH ENOUGH
TO AVOID A HEADLINE FOR FLASH FLOODING. HOWEVER...THE TIMING OF
THE RAINFALL AND LIKELIHOOD THAT IT WILL FALL DURING THE LATE
EVENING HOURS ON A WEEKEND EVENING OVER URBAN AREAS IS A CONCERN.
PONDING OF WATER AND SOME STREET FLOODING COULD BE A PROBLEM
ACROSS MOSTLY URBAN AREAS. EVENTUALLY THE LINE WILL BE NEARLY OUT
OF THE AREA BY 10-13Z AS THE FORWARD MOTION TAKES IT INTO NORTHERN
MO AND SOUTHEAST IA BY 13Z.
THE REMAINDER OF THE FORECAST IS FAIRLY BENIGN. ONCE THE VIGOROUS
H500 TROUGH MOVE EAST INTO THE GREAT LAKES SUNDAY INTO MONDAY MUCH
COOLER AND DRIER WEATHER WILL BE EXPECTED FROM SUNDAY THROUGH
TUESDAY. A GRADUAL WARMING TREND IS EXPECTED FROM WEDNESDAY THROUGH
FRIDAY WITH A WEAK WAVE IMPACTING THE REGION ON THURSDAY. HIGHS WILL
WARM FROM THE LOWER TO MID 70S EARLY IN THE PERIOD TO THE MID 70S TO
LOWER 80S LATE IN THE PERIOD. LOWS RECOVER FROM THE 40S/50S TO THE
50S/60S LATER IN THE PERIOD.
&&
.AVIATION...22/18Z
ISSUED AT 108 PM CDT SAT AUG 22 2015
AVIATION CONCERNS WILL REVOLVE AROUND THUNDERSTORM CHANCES THROUGH
THE EVENING THEN GUSTY WINDS ON SUNDAY. LOCAL MVFR THROUGH THE
AFTERNOON THEN EXPECT THUNDERSTORMS TO DEVELOP OVER WRN IA AFT
21Z. STRONG THUNDERSTORM WIND GUSTS FROM THE WEST APPROACHING 50
KTS MAY OCCUR. EXPECT MVFR CIGS WITH THUNDERSTORMS POSSIBLE
DROPPING TO IFR IN LOCATIONS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DONAVON
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1244 PM EDT SAT AUG 22 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION AND STALL ACROSS DOWNEAST MAINE
THIS AFTERNOON WHILE HIGH PRESSURE BUILDS IN BRIEFLY ACROSS THE
NORTHERN AREAS. THE STALLED FRONT IS EXPECTED TO RETURN NORTH AS
A WARM FRONT SUNDAY INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1245 PM UPDATE...SCATTERED SHOWERS ARE ONGOING ACROSS MUCH OF
DOWNEAST MAINE, ESPECIALLY IN A BAND FROM DANFORTH DOWN THROUGH
BANGOR. THIS TREND WILL CONTINUE THROUGH THE AFTERNOON. THE LATEST
HRRR IS STILL SHOWING THAT THERE`LL BE MORE COVERAGE TOWARD
EVENING, THOUGH IT`S SHIFTED THE HIGHEST CONCENTRATION OF SHOWERS
A BIT FURTHER NORTH INTO SOUTHERN AROOSTOOK COUNTY. HAVE KEPT POPS
THE SAME FOR NOW, EXCEPT TRIMMED BACK TO ISOLATED SHOWERS FOR
SOUTHERN PISCATAQUIS COUNTY, WHERE NO SHOWERS ARE CURRENTLY
FALLING. NO OTHER CHANGES NEEDED.
PREVIOUS DISCUSSION...SURFACE ANALYSIS HAD THE COLD FRONT SLOWLY
WORKING ITS WAY E ACROSS WESTERN MAINE. AREAS OF FOG ALONG THE
IMMEDIATE COAST THIS MORNING. THE LATEST RUN OF THE HRRR KM AND
RAP HAD A GOOD HANDLE ON THINGS ATTM KEEPING HIGHER POPS OVER
EASTERN AREAS THIS MORNING INTO THE AFTERNOON AS THE FRONT SAGS
ESE AND THEN STALLS ACROSS DOWNEAST MAINE COAST. LLVL CONVERGENCE
AND SOME WEAK MID LEVEL FORCING WILL ALLOW FOR SHOWERS TO CONTINUE
ACROSS THE AFOREMENTIONED AREAS INTO EARLY EVENING. INSTABILITY IS
THERE ESPECIALLY FOR WASHINGTON AND HANCOCK COUNTY. SOUNDING DATA
SUPPORTED SBCAPES OF 500-800 JOULES AND LIS DOWN TO -3 W/PWATS OF
1.8+ INCHES. LOW/MID LEVEL LAPSE RATES OF 6.2 C/KM EXPECTED, SO
TSTM POTENTIAL IS THERE. HIGH FREEZING LEVELS AND WBZS(14K FT)
WILL ALLOW FOR ANY TSTMS TO CONTAIN HEAVY RAINFALL. 0-6KM SHEAR
AROUND 12 KTS W/SW FLOW THROUGH 700MBS WILL ALSO ALLOW ANY STORMS
TO TRAIN OVER THE SAME AREAS. THIS ALL HINGES ON HEATING POTENTIAL
WHICH COULD BE DELAYED FOR A WHILE. THEREFORE, DECIDED TO CARRY
TSTMS FOR THE DOWNEAST ESPECIALLY HANCOCK AND WASHINGTON COUNTY
BUT LEFT OUT ENHANCED WORDING ATTM. WILL TAKE ANOTHER LOOK AT
THINGS W/6 AM UPDATE. FURTHER NORTH ACROSS PISCATAQUIS AND
AROOSTOOK COUNTY, DRIER W/SOME PARTIAL CLEARING EXPECTED.
FOR TONIGHT, THE FRONT LOOKS AS THOUGH IT TRIES TO BUCKLE BACK TO
THE NORTH AS A WEAL UPPER LOW LIFTS ACROSS THE WESTERN ATLC. SHOWERS
EXPECTED TO EDGE A BIT FURTHER NNE INTO CENTRAL PENOBSCOT AND
NORTHERN WASHINGTON COUNTY. FURTHER N AND W., DRIER AND A BIT
COOLER OVERNIGHT. FOG LOOKS TO BE A THREAT OVERNIGHT ESPECIALLY
WHERE RAINFALL OCCURRED. TEMPERATURES ARE EXPECTED TO BE IN THE
UPPER 50S TO LOWER 60S NORTH AND WEST W/MID 60S FOR THE DOWNEAST
AND COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
LOW PRESSURE WILL MEANDER ACROSS THE NW ATLANTIC DURING SUNDAY AS
AN AREA OF HIGH PRESSURE MOVES EAST ACROSS THE MARITIMES. A MOIST
EAST TO SOUTHEAST FLOW AROUND THESE SYSTEMS WILL KEEP A CHANCE OF
SHOWERS AND PERHAPS AN AFTERNOON TSTM TO MAINLY PORTIONS OF
CENTRAL AND DOWN EAST MAINE SUNDAY AFTERNOON. THE LOW WILL SLOWLY
START TO DRIFT EAST MONDAY NIGHT THROUGH TUESDAY. MOISTURE
ASSOCIATED WITH AN APPROACHING TROF FROM THE GREAT LAKES REGION
WILL CONTINUE THE THREAT OF SHOWERS THROUGH MONDAY ALONG WITH THE
CHANCE FOR A FEW AFTERNOON THUNDERSTORMS. HIGH TEMPERATURES BOTH
SUNDAY AND MONDAY WILL BE IN THE MID TO NEAR 80 DEGREES. LOWS
SUNDAY NIGHT WILL BE IN THE 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
UNSETTLED WEATHER CONDITIONS WILL PERSIST THROUGH THURSDAY AS A
TROF OF LOW PRESSURE TO OUR WEST SLOWLY CROSSES THE REGION THROUGH
THURSDAY. THIS WILL BRING A CONTINUED THREAT FOR SHOWERS THROUGH
THURSDAY. WE SHOULD START TO DRY OUT A BIT BY THURSDAY NIGHT AND
FRIDAY BEFORE ANOTHER SYSTEM BRINGS THE CHANCE FOR SHOWERS BY NEXT
WEEKEND.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: MVFR FOR KBGR AND IFR/LIFR KBHB THIS MORNING W/VFR
ACROSS THE NORTHERN TERMINALS. SOME IMPROVEMENT EXPECTED FOR KBHB
TO MVFR LATER THIS AFTERNOON. KBGR COULD DROP BACK TO IFR THIS
MORNING BEFORE RECOVERING BACK TO MVFR AND POSSIBLY VFR THIS
AFTERNOON. ACROSS THE NORTH, PERIODS OF MVFR EXPECTED THIS MORNING
W/A RECOVERY TO VFR. FOG POTENTIAL FOR TONIGHT COULD ALLOW
CONDITIONS TO GO TO MVFR NORTH OF KBHB WHILE KBHB DOWN TO IFR.
SHORT TERM: CONDITIONS WILL VARY AT TIMES THROUGH THE PERIOD FROM
VFR DOWN TO IFR IN SHOWERS AND PATCHY MAINLY NIGHTTIME FOG.
&&
.MARINE...
NEAR TERM: NO HEADLINES EXPECTED THIS TERM. SSE SWELL OF 2 FT OUT
THERE ATTM AND A SLIGHT BUILD IN WAVE HEIGHTS EXPECTED TONIGHT.
WINDS WILL REMAIN 10 KTS OR LESS W/FOG A NUISANCE TO NAVIGATION.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS THROUGH THE PERIOD.
&&
.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 BISMARCK ND
106 PM CDT SAT AUG 22 2015
.UPDATE...
ISSUED AT 1259 PM CDT SAT AUG 22 2015
POPULATED THE POPS GRIDS WITH HRRR BLENDED MODEL WHICH SEEMED TO
CAPTURE THE NARROW DRY SLOT SOUTHWEST AT THIS TIME. LOWERED
TEMPERATURES ABOUT 2 DEGREES AS TEMPS WILL BE NEARLY STEADY OR
FALL A LITTLE WEST.
UPDATE ISSUED AT 923 AM CDT SAT AUG 22 2015
WINDS GENERALLY IN THE ADVISORY CRITERIA SOUTHWEST SO FAR TODAY.
WILL KEEP THE HIGH WIND WARNING GOING AS EXPECT THE GRADIENT WIND
TO INCREASE. ADJUSTED THE POPS TO FIT THE CURRENT SHOWERS. SEEING
FAIRLY WIDESPREAD SHOWERS NORTH CENTRAL WITH SCATTERED T. EXPECT
THE SHOWERS TO FILL IN WITH TIME WEST AND SOUTH CENTRAL.
UPDATE ISSUED AT 638 AM CDT SAT AUG 22 2015
GIVEN SATELLITE AND RADAR TRENDS THROUGH 1130 UTC...THE 06 UTC
NAM AND NAM CONUS NEST...AND 09-10 UTC HRRR ITERATIONS...REDUCED
POPS FOR THIS MORNING INTO THE AFTERNOON SOUTH CENTRAL AND INTO
THE JAMES RIVER VALLEY IN ASSOCIATION WITH THE DRY SLOT.
HOWEVER...THESE AREAS ARE EXPECTED TO BE IMPACTED BY DEFORMATION
ZONE RAINFALL BY LATE AFTERNOON/EARLY EVENING AND INTO THE NIGHT.
NO CHANGES TO WIND HEADLINES AT THIS TIME. HOWEVER...THE 06 UTC
GFS/NAM 0.5 KM WIND FIELDS SUGGEST 50 KT OR GREATER GUSTS MAY BE
POSSIBLE ACROSS A WIDER PORTION OF THE AREA LATE THIS AFTERNOON
AND THROUGH THE EVENING. SHOULD THIS TREND CONTINUE...AN EXPANSION
OF THE HIGH WIND WARNING MAY BE NEEDED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SAT AUG 22 2015
CURRENT SURFACE ANALYSIS PLACES COLD FRONT WORKING ITS WAY INTO
THE WESTERN DAKOTAS. UPPER LEVEL ANALYSIS PLACES SOUTHWEST FLOW
OVER THE NORTHERN PLAINS WHILE TROF WORKS ITS WAY OUT OF THE
NORTHERN ROCKIES TOWARDS THE PLAINS. INITIAL WAVE LIFTING AHEAD OF
THE TROUGH CONTINUES TO PRODUCE SOME SHOWERS WITH A FEW
THUNDERSTORMS OVER WESTERN PORTIONS OF NORTH DAKOTA.
FOR TODAY...COLD FRONT WILL CONTINUE TO ADVANCE THROUGH THE AREA
WITH NORTHWEST WINDS INCREASING IN ITS WAKE. STRONGEST WINDS WILL
BE OVER SOUTHWEST NORTH DAKOTA WHERE GREATEST PRESSURE RISES ARE
EXPECTED BY AROUND MID-DAY. THE GUSTY WINDS WILL CONTINUE TO
SPREAD EASTERLY THROUGH CENTRAL NORTH DAKOTA BY LATE AFTERNOON.
PRECIPITATION WILL CONTINUE TO DEVELOP AND SPREAD THROUGH THE AREA
AS TROUGH MAKES ITS ADVANCE INTO THE AREA...WITH THE GREATEST
PRECIPITATION CHANCES/AMOUNTS EXPECTED TO BE OVER THE NORTHERN
PORTIONS OF THE STATE. WILL KEEP SOME MENTION OF THUNDER IN
THROUGH THE PERIOD...THOUGH EXPECT THE STRONGER STORMS TO REMAIN
TO THE EAST OF THE AREA WHERE GREATEST INSTABILITY IS NOTED AHEAD
OF THE FRONT.
FOR TONIGHT...WINDS ARE EXPECTED TO PEAK IN THE EARLY EVENING OVER
CENTRAL NORTH DAKOTA WHEN STRONGEST PRESSURE RISES FOR THAT AREA
MOVE THROUGH. LATEST FORECAST SOUNDINGS KEEP MIXING THE STRONGER
WINDS DOWN THROUGH THE EVENING HOURS SO HAVE EXTENDED THE TIMING
OF THE WIND ADVISORY OVER THAT AREA. OTHERWISE...PRECIPITATION
SHIELD WILL TRACK FROM WEST TO EAST WITH CONDITIONS STARTING TO
DRY OUT OVER THE WEST IN THE EVENING. A FEW CLAPS OF THUNDER WILL
REMAIN POSSIBLE IN THE EARLY EVENING...WITH ONLY SHOWERS EXPECTED
BY LATE EVENING/OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 315 AM CDT SAT AUG 22 2015
A RETURN TO NOMINAL LATE AUGUST SENSIBLE WEATHER HIGHLIGHTS THE
EXTENDED FORECAST.
GIVEN GOOD AGREEMENT AMONGST THE 00 UTC DETERMINISTIC AND ENSEMBLE
SUITES...WILL USE A BLEND FOR ALL FIELDS. OVERALL...AFTER A COOL
AND BREEZY SUNDAY IN THE WAKE OF THE STORM SYSTEM FROM THE SHORT
TERM...A RETURN TO RATHER NORMAL CONDITIONS ARE EXPECTED NEXT
WEEK AS AN INTERMOUNTAIN WEST RIDGE AMPLIFIES. HOWEVER...THE TREND
IN THE 00 UTC CONSENSUS IS FOR THE RIDGE AXIS TO A BIT FURTHER
WEST THAN PREVIOUS RUNS...RESULTING IN A COOLER...ALBEIT NEAR
NORMAL...FORECAST FOR TEMPERATURES FOR NEXT WEEK COMPARED TO
PREVIOUS FORECAST ITERATIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1259 PM CDT SAT AUG 22 2015
HAZARDS TO AVIATION INCLUDE STRONG WEST TO NORTHWEST SURFACE WINDS
AND MVFR TO LOCAL IFR CONDITIONS IN SHOWERS. DEEP SURFACE LOW OVER
EASTERN NORTH DAKOTA WILL MOVE NORTHEAST BRINGING STRONG AND
GUSTY NORTHWEST WINDS OF 25 TO 45 KTS ACROSS WETS AND CENTRAL
NORTH DAKOTA. MVFR TO LOCAL IFR CONDITIONS IN CLOUDS AND SHOWERS
IMPROVING TO VFR AFTER 06Z MOST AREAS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ SUNDAY FOR
NDZ002>005-010>013-019>023-025-034>037-042-045>048-050-051.
HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR NDZ031>033-040-
041-043-044.
WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR NDZ001-009-017-
018.
&&
$$
UPDATE...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
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.
&&
$$
Johnson/Daniels
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1226 PM CDT SAT AUG 22 2015
.AVIATION...
/18Z TAFS/
Low stratus has eroded across the area, resulting in VFR
conditions. South winds have increased to 12-16 kts, with gusts
over 20 kts at times. Expect a few high-based Cu this afternoon,
dissipating around sunset. The HRRR model is developing a few
thunderstorms over the western Concho Valley by late afternoon,
but remains the outlier with dry conditions anticipated through
the period. A cold front will move south into the Big Country late
on Sunday, shifting winds to the northeast.
Johnson
&&
.PREV DISCUSSION... /ISSUED 657 AM CDT SAT AUG 22 2015/
AVIATION...
/12Z TAFS/
MVFR stratus will affect the southern terminals this morning,
otherwise VFR conditions will prevail today. Could see an
isolated shower or thunderstorm develop late this afternoon across
the southern terminals but coverage expected to be too limited
to mention at this time. Stratus is not expected to be as
widespread early Sunday morning and will only include a scattered
group across the southern terminals for now.
PREV DISCUSSION... /ISSUED 431 AM CDT SAT AUG 22 2015/
SHORT TERM...
(Today and Tonight)
Hot and dry conditions will prevail today as the upper level ridge
dominates. Some early morning low clouds will give way to mostly
sunny skies, with breezy south winds developing. Temperatures today
will be slightly above normal, with afternoon highs topping out in
the mid and upper 90s, coolest across far southern counties.
Tonight will be dry and warm, with some low clouds developing
across southern counties after midnight. Expect overnight lows in
the mid and upper 70s.
24
LONG TERM...
(Sunday through Friday)
An upper trough will move east into the upper Midwest by Sunday
morning, with associated cold front moving south into the Big
Country Sunday afternoon and evening. The weak cold front will
sag south into our central counties Sunday night before stalling.
Showers and thunderstorms will be possible along and behind the
front. Carrying 20-30 PoPs for the Big Country area along/north
of I-20 Sunday afternoon and evening, with slight chance PoP
expanding south into the northern Heartland and Concho Valley
Sunday night.
With presence of the weak boundary on Monday along with sufficient
instability and moisture, have 20-30 PoPs for showers and
thunderstorms with the higher rain chance northeast of a
Sweetwater to Brownwood line.
The models look to be somewhat in flip-flop mode for rain chances
on Tuesday. The 00Z GFS is much drier than the ECMWF, and what`s
left of the boundary by that time will be positioned across our
north or northeast counties. With collaborative considerations,
carrying slight chance PoP for our area on Tuesday, with low
confidence in any significant shower/thunderstorm activity.
Temperatures will be a few degrees cooler across the Big Country
on Monday and Tuesday, with little temperature change expected
for the southern half of our area. Highs in the mid to upper 90s
are expected Wednesday through Friday.
The upper high is progged to shift slowly southwest across New
Mexico on Wednesday, and into southern Arizona on Thursday. As
this upper high retreats to the Desert Southwest late in the week,
northwest flow aloft will develop over our area, allowing
shortwaves to drop southeast into the southern Plains and Texas.
The first of these may affect our area Thursday night into Friday.
With collaborative considerations, and awaiting model consistency,
have not added PoPs yet.
Although just beyond the scope of this forecast, a more potent
shortwave trough is progged to drop south into our area next
weekend along with a cold front, which would result in more
substantial rain chances.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 97 76 97 72 / 5 5 20 30
San Angelo 99 75 100 73 / 5 5 10 10
Junction 96 74 98 73 / 5 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
25