Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/27/13
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1045 PM PDT SAT AUG 24 2013
NEW AVIATION DISCUSSION
.SYNOPSIS...
DRY WEATHER WITH NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES CAN
BE EXPECTED THROUGH SUNDAY. A MOIST AIR MASS FROM THE SOUTH WILL
BRING THE SLIGHT CHANCE OF THUNDERSTORMS TO THE LOS ANGELES COUNTY
MOUNTAINS AND ANTELOPE VALLEY MONDAY...THEN TO MUCH OF VENTURA AND
LOS ANGELES COUNTIES MONDAY NIGHT INTO TUESDAY. AN UPPER LEVEL
RIDGE OF HIGH PRESSURE WILL BUILD INTO SOUTHERN CALIFORNIA BY THE
MIDDLE TO END OF NEXT WEEK WITH ABOVE NORMAL TEMPERATURES
EXPECTED.
&&
.UPDATE...
ONSHORE FLOW REMAINS IN PLACE ACROSS THE AREA THIS EVENING ALONG
WITH A STUBBORN MARINE LAYER. THE LATEST MODEL SOLUTIONS CONTINUE
TO SUGGEST ONSHORE FLOW WEAKENING ACROSS THE AREA ON SUNDAY ALONG
WITH INCREASING 500 MB HEIGHTS. WITH THIS MIND...A WARMING TREND
REMAINS INTACT ACROSS THE AREA...ESPECIALLY ALONG THE COAST.
THE FORECAST WILL HAVE TO BE MONITORED FOR DEVELOPMENT AS
MOISTURE IS STARTING TO PUSH INTO THE HIGH DESERTS OF SOUTHERN
CALIFORNIA. CURRENTLY...THE PACKAGE HAS NO POPS OR WEATHER FOR THE
ANTELOPE VALLEY. HOWEVER...KVCV DEW POINTS HAVE SURGED INTO THE
LOWER 50S THIS HOUR...AND KL35 INTO THE 40S. MODEL SOLUTIONS
CONTINUE TO KEEP THE BEST MOISTURE AND INSTABILITY SOUTH AND EAST
OF THE AREA...BUT DEW POINT DEVELOPMENTS ARE STARTING TO BE
PROBLEMATIC. 13-KM RAP MODEL SOLUTION ARE ALSO STARTING HINT AT
THE POSSIBILITY OF CONVECTIVE STORM OVER THE EASTERN SAN GABRIEL
RANGE. THE NEXT SHIFT WILL BE BRIEFED ACCORDINGLY.
&&
.PREV DISCUSSION...
SHORT TERM...12Z MODELS TODAY STARTED TO SHOW A RETURN OF IVO
MOISTURE BACK INTO THE EASTERN PART OF OUR FORECAST AREA MONDAY
AND ESPECIALLY MONDAY NIGHT INTO TUESDAY. THE GFS AND GEM MODELS
HAD SHOWN THIS AT ONE TIME BUT BACKED OFF IN FAVOR OF THE TROF TO
THE NORTH USHERING IN MORE DRY AIR FROM THE SOUTHWEST AND PUSHING
THE MOISTURE EAST. THE NAM IS THE MOST AGGRESSIVE WITH THE
MOISTURE BUT ALL MODELS SHOW A PRETTY DRAMATIC INCREASE FROM THE
SOLUTIONS OVER THE LAST COUPLE DAYS. THIS COULD BE JUST A BRIEF
FLING WITH WETTER SOLUTIONS BEFORE WAGGING BACK TO A DRIER
SOLUTION TONIGHT OR SUNDAY BUT GIVEN THE CONSENSUS IT SEEMS
WARRANTED TO RE-INTRODUCE AT LEAST SOME LOW CHANCES OF
SHOWERS/STORMS TO LA/VENTURA COUNTIES MONDAY NIGHT INTO TUESDAY.
THE NAM ALSO SHOWS RESPECTABLE CAPE AS WELL AS K/LIFTED INDICES
DURING THAT TIME, THOUGH MODEL SOUNDINGS ACROSS SOUTHERN LA COUNTY
SEEMED TO SUGGEST MORE OF A STRATIFORM PRECIP EVENT
(SPRINKLES/LIGHT SHOWERS) RATHER THAN A CONVECTIVE ONE WITH
COOLING IN THE LOWER LVLS AND SOME WARMING ALOFT. PWATS INCREASE
TO AN IMPRESSIVE 1.75-2" MONDAY NIGHT AND EARLY TUESDAY FOR
LA/VENTURA COUNTIES WHILE 850 DEW POINTS INCREASE TO BETWEEN
12-14C. BY TUESDAY AFTERNOON PRECIP THREAT SHOULD BE CONFINED TO
THE MOUNTAINS WHERE THE MOST UNSTABLE AIR WILL BE.
LONG TERM...A BREAK EXPECTED IN THE MONSOON SURGE ON WEDNESDAY
BEFORE MORE MOISTURE ARRIVES STARTING THURSDAY AND CONTINUING INTO
THE WEEKEND. ADDED SOME TSTM CHANCES BACK TO THE MOUNTAINS AND
ANTELOPE VALLEY BUT LEAVING COASTAL/VALLEY AREAS DRY FOR NOW. AT
THE SAME TIME HIGH PRESSURE OVER THE SOUTHWEST IS EXPECTED TO
EXPAND OVER CALIFORNIA AND BRING A WARMING TREND TO THE AREA.
LOOKING BEYOND THAT THE NEXT TROPICAL CYCLONE IS EXPECTED TO
DEVELOP OFF SOUTHERN MEXICO AROUND THE MIDDLE OF NEXT WEEK AND
EVENTUALLY BRING YET ANOTHER SURGE OF MOISTURE TO THE AREA LATE
NEXT WEEKEND OR EARLY THE FOLLOWING WEEK. SO WE`RE LOOKING AT AN
EXTENDED PERIOD OF POTENTIALLY WARM AND MUGGY CONDITIONS, WHICH IS
TO BE EXPECTED THIS TIME OF YEAR.
&&
.AVIATION...
25/0545Z
SHALLOW 900 FOOT DEEP MARINE LAYER COMBINED WITH A WEAK EDDY WILL
BRING LIFR TO IFR CIGS TO THE COASTAL TAF SITES OVERNIGHT. ARRIVAL
TIMING COULD BE AS MUCH AS TWO HOURS OFF BUT BETTER CONFIDENCE IN
CLEARING TIMES.
KLAX...GOOD CONFIDENCE IN TAF CIGS COULD BOUNCE FROM LIFR TO IFR
BETWEEN 07Z-13Z. NOTE: PREVAILING 1/4SM VIS IS A RESULT OF THE
OBSERVATION DECKS ELEVATED TOWER LOCATION. TAF VIS REFLECTS THE
ACTUAL SFC VIS.
KBUR...HIGH CONFIDENCE IN CAVU TAF.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...HALL/MW
AVIATION...HALL
SYNOPSIS...SIRARD
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
918 PM PDT SAT AUG 24 2013
.SYNOPSIS...
DRY WEATHER WITH NEAR OR SLIGHTLY ABOVE NORMAL TEMPERATURES CAN
BE EXPECTED THROUGH SUNDAY. A MOIST AIR MASS FROM THE SOUTH WILL
BRING THE SLIGHT CHANCE OF THUNDERSTORMS TO THE LOS ANGELES COUNTY
MOUNTAINS AND ANTELOPE VALLEY MONDAY...THEN TO MUCH OF VENTURA AND
LOS ANGELES COUNTIES MONDAY NIGHT INTO TUESDAY. AN UPPER LEVEL
RIDGE OF HIGH PRESSURE WILL BUILD INTO SOUTHERN CALIFORNIA BY THE
MIDDLE TO END OF NEXT WEEK WITH ABOVE NORMAL TEMPERATURES
EXPECTED.
&&
.UPDATE...
ONSHORE FLOW REMAINS IN PLACE ACROSS THE AREA THIS EVENING ALONG
WITH A STUBBORN MARINE LAYER. THE LATEST MODEL SOLUTIONS CONTINUE
TO SUGGEST ONSHORE FLOW WEAKENING ACROSS THE AREA ON SUNDAY ALONG
WITH INCREASING 500 MB HEIGHTS. WITH THIS MIND...A WARMING TREND
REMAINS INTACT ACROSS THE AREA...ESPECIALLY ALONG THE COAST.
THE FORECAST WILL HAVE TO BE MONITORED FOR DEVELOPMENT AS
MOISTURE IS STARTING TO PUSH INTO THE HIGH DESERTS OF SOUTHERN
CALIFORNIA. CURRENTLY...THE PACKAGE HAS NO POPS OR WEATHER FOR THE
ANTELOPE VALLEY. HOWEVER...KVCV DEW POINTS HAVE SURGED INTO THE
LOWER 50S THIS HOUR...AND KL35 INTO THE 40S. MODEL SOLUTIONS
CONTINUE TO KEEP THE BEST MOISTURE AND INSTABILITY SOUTH AND EAST
OF THE AREA...BUT DEW POINT DEVELOPMENTS ARE STARTING TO BE
PROBLEMATIC. 13-KM RAP MODEL SOLUTION ARE ALSO STARTING HINT AT
THE POSSIBILITY OF CONVECTIVE STORM OVER THE EASTERN SAN GABRIEL
RANGE. THE NEXT SHIFT WILL BE BRIEFED ACCORDINGLY.
&&
.PREV DISCUSSION...
SHORT TERM...12Z MODELS TODAY STARTED TO SHOW A RETURN OF IVO
MOISTURE BACK INTO THE EASTERN PART OF OUR FORECAST AREA MONDAY
AND ESPECIALLY MONDAY NIGHT INTO TUESDAY. THE GFS AND GEM MODELS
HAD SHOWN THIS AT ONE TIME BUT BACKED OFF IN FAVOR OF THE TROF TO
THE NORTH USHERING IN MORE DRY AIR FROM THE SOUTHWEST AND PUSHING
THE MOISTURE EAST. THE NAM IS THE MOST AGGRESSIVE WITH THE
MOISTURE BUT ALL MODELS SHOW A PRETTY DRAMATIC INCREASE FROM THE
SOLUTIONS OVER THE LAST COUPLE DAYS. THIS COULD BE JUST A BRIEF
FLING WITH WETTER SOLUTIONS BEFORE WAGGING BACK TO A DRIER
SOLUTION TONIGHT OR SUNDAY BUT GIVEN THE CONSENSUS IT SEEMS
WARRANTED TO RE-INTRODUCE AT LEAST SOME LOW CHANCES OF
SHOWERS/STORMS TO LA/VENTURA COUNTIES MONDAY NIGHT INTO TUESDAY.
THE NAM ALSO SHOWS RESPECTABLE CAPE AS WELL AS K/LIFTED INDICES
DURING THAT TIME, THOUGH MODEL SOUNDINGS ACROSS SOUTHERN LA COUNTY
SEEMED TO SUGGEST MORE OF A STRATIFORM PRECIP EVENT
(SPRINKLES/LIGHT SHOWERS) RATHER THAN A CONVECTIVE ONE WITH
COOLING IN THE LOWER LVLS AND SOME WARMING ALOFT. PWATS INCREASE
TO AN IMPRESSIVE 1.75-2" MONDAY NIGHT AND EARLY TUESDAY FOR
LA/VENTURA COUNTIES WHILE 850 DEW POINTS INCREASE TO BETWEEN
12-14C. BY TUESDAY AFTERNOON PRECIP THREAT SHOULD BE CONFINED TO
THE MOUNTAINS WHERE THE MOST UNSTABLE AIR WILL BE.
LONG TERM...A BREAK EXPECTED IN THE MONSOON SURGE ON WEDNESDAY
BEFORE MORE MOISTURE ARRIVES STARTING THURSDAY AND CONTINUING INTO
THE WEEKEND. ADDED SOME TSTORM CHANCES BACK TO THE MOUNTAINS AND
ANTELOPE VALLEY BUT LEAVING COASTAL/VALLEY AREAS DRY FOR NOW. AT
THE SAME TIME HIGH PRESSURE OVER THE SOUTHWEST IS EXPECTED TO
EXPAND OVER CALIFORNIA AND BRING A WARMING TREND TO THE AREA.
LOOKING BEYOND THAT THE NEXT TROPICAL CYCLONE IS EXPECTED TO
DEVELOP OFF SOUTHERN MEXICO AROUND THE MIDDLE OF NEXT WEEK AND
EVENTUALLY BRING YET ANOTHER SURGE OF MOISTURE TO THE AREA LATE
NEXT WEEKEND OR EARLY THE FOLLOWING WEEK. SO WE`RE LOOKING AT AN
EXTENDED PERIOD OF POTENTIALLY WARM AND MUGGY CONDITIONS, WHICH IS
TO BE EXPECTED THIS TIME OF YEAR.
&&
.AVIATION...25/0000Z.
AT COASTAL TERMINALS...LIFR TO IFR CONDITIONS WILL REDEVELOP THROUGH
11Z...POSSIBLY LOWERING ONE CATEGORY BETWEEN 08Z AND 15Z ESPECIALLY
NORTH OF POINT CONCEPTION. VFR CONDITIONS SHOULD REDEVELOP BETWEEN
16Z AND 18Z. THERE IS A SLIGHT CHANCE THAT SUB-VFR CONDITIONS COULD
LINGER BEYOND 18Z.
KLAX...IFR CONDITIONS WILL LIKELY PERSIST THROUGH AT LEAST
04Z...THEN LOWER TO LIFR BETWEEN 04Z AND 08Z. THERE IS A 30 PERCENT
CHANCE OF VLIFR CONDITIONS BETWEEN 08Z AND 15Z. VFR CONDITIONS
SHOULD REDEVELOP BETWEEN 16Z AND 18Z. THERE IS A 20 PERCENT CHANCE
THAT SUB-VFR CONDITIONS LINGERING BEYOND 18Z.
KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
&&
$$
PUBLIC...HALL/MW
AVIATION...HALL
SYNOPSIS...SIRARD
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS TAUNTON MA
939 PM EDT MON AUG 26 2013
.SYNOPSIS...
SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY
AS A SERIES OF DISTURBANCES MOVE ACROSS NEW ENGLAND. DRY WEATHER
WILL FOLLOW LATER THIS WEEK WITH ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS POSSIBLE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
930 PM UPDATE...
ONLY CHANGE TO PREVIOUS FORECAST WAS TO INCREASE POPS ACROSS
SOUTHERN NH GIVEN UPSTREAM OBS ACROSS NORTHERN NY INTO VT. SO
EXPECTING MOST LOCATIONS IN SOUTHERN NH TO MEASURE SOME RAINFALL
TONIGHT. OTHERWISE EARLIER FORECAST ON TRACK.
THE CULPRIT FOR THE SHOWERS AND EMBEDDED TSTMS IS AN IMPRESSIVE
SHORT WAVE MOVING ACROSS LAKE ONTARIO AND NY STATE. LIGHTNING
HAS BEEN ON A DOWNWARD TREND PAST FEW HOURS. AT 930 PM DUAL POL
ESTIMATING MAX HRLY RNFL 0.8 TO 1.0 IN AROUND THE NORTHAMPTON
AREA. THIS COMBINED WITH PWATS NEAR 2.0 INCHES WILL YIELD A LOW
RISK OF MINOR POOR DRAINAGE FLOODING OVERNIGHT IN THE URBAN AREAS.
LATEST HRRR AND 12Z ECMWF SUGGEST STRONGEST FORCING FOR ASCENT
ACROSS PA/NY AND POSSIBLY INTO WESTERN MA AND CT GIVEN PROXIMITY
OF LFQ OF UPPER LEVEL JET STREAK...ENHANCING QG FORCING. THEREFORE
HEAVIEST RAINFALL LIKELY ACROSS WESTERN MA/CT AND POSSIBLY INTO
RI.
RISK OF STRONG STORMS VERY LOW WITH INSTAB AND SHEAR OUT OF PHASE
WITH EACH OTHER...BEST INSTABILITY ALOFT ACROSS NORTHERN NEW
ENGLAND...WHILE STRONGEST WIND FIELD ALOFT ACROSS PA/NY/NJ NEAR
LFQ OF UPPER JET.
WARM AND MUGGY OVERNIGHT WITH DEW PTS IN THE M60S TO L70S
PRECLUDING TEMPS FROM FALLING MUCH.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
TUESDAY...
ANY LEFTOVER SHOWERS/SCT TSTMS WILL EXIT ACROSS THE S COAST DURING
THE MORNING. HAVE LEFT IN LOW LIKELY POPS THERE EARLY...THEN WILL
STEADILY IMPROVE TOWARD MIDDAY. HOWEVER...WILL STILL BE UNDER
CYCLONIC FLOW ALOFT...SO STILL COULD SEE WIDELY SCT SHOWERS OR AN
ISOLD TSTM MAINLY ACROSS INLAND AREAS WITH FAIRLY GOOD INSTABILITY
IN PLACE. ONLY PROBLEM FOR ANY STRONGER STORMS TO DEVELOP WILL BE
LACK OF SHEAR AND WINDS AT THE SURFACE AND ALOFT REMAIN LIGHT. MAY
SEE BRIEF HEAVY DOWNPOURS WITH ANY SHOWER OR STORM. HIGHS WILL
REACH THE LOWER-MID 80S...EXCEPT THE MID-UPPER 70S ALONG THE
IMMEDIATE COAST.
TUESDAY NIGHT...
LONG WAVE TROUGHING REMAINS JUST E OF THE REGION...KEEPING JUST
ENOUGH CYCLONIC FLOW IN PLACE TO TRY TO ROTATE SOME WIDELY SCT
SHOWERS OR EVEN AN ISOLD TSTM TOWARD THE E COAST. OTHERWISE...ANY
SHOWERS/TSTMS INLAND SHOULD END WITHIN AN HOUR OR SO OF SUNSET.
WITH MUGGY AIRMASS REMAINING IN PLACE...EXPECT LOWS ONLY IN THE
60S ALONG WITH PATCHY FOG DEVELOPING MAINLY AFTER MIDNIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGHLIGHTS...
* UNSETTLED WEATHER EXPECTED WED AND THU
* DRY AND INCREASINGLY WARM WEATHER END OF THE WEEK
* UNSETTLED WEATHER RETURNS EARLY NEXT WEEK
MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE BROAD SCALE THOUGH THERE
ARE DEFINITELY DISCREPANCIES IN THE DETAILS...PARTICULARLY DURING
THE UNSETTLED PERIODS OF WEATHER. THE WPC IS OPTING FOR A BLEND OF
THE GEFS AND THE ECMWF ENSEMBLE MEANS WHICH ARE IN THE MIDDLE OF THE
SOLUTION ENVELOPE WHILE THE RESPECTIVE OPERATIONAL MODELS ARE
TRENDING TO THE OUTSIDE. THAT BEING SAID...WILL TRY TO USE AS MUCH
OF THE WPC FORECAST AS POSSIBLE TO INCORPORATE THE ENSEMBLE MEANS.
A SERIES OF LOW PRESSURE CENTERS WILL TRAVEL ALONG OR JUST SOUTH OF
40 N LATITUDE WEDNESDAY AND INTO THE MARITIMES THURSDAY AS HIGH
PRESSURE BUILDS INTO SOUTHERN NEW ENGLAND. HIGH PRESSURE WILL BE
THE DOMINANT WEATHER FEATURE FRIDAY AND SATURDAY THEN MOVES
OFFSHORE...ALLOWING LOW PRESSURE TO MOVE INTO QUEBEC AND BRINGING A
COLD FRONT THROUGH SOUTHERN NEW ENGLAND MONDAY.
WEDNESDAY AND THURSDAY...ONE OR MORE LOW PRESSURE CENTERS WILL MOVE
SOUTH OF SOUTHERN NEW ENGLAND...CONTINUING THE UNSETTLED WEATHER
OVER THE AREA TODAY AND TUESDAY. TRICKY FORECAST FOR SEVERE STORM
POTENTIAL. WHILE THERE IS MORE LIFT ON WEDNESDAY WITH LOW PRESSURE
NEARER TO SOUTHERN NEW ENGLAND...THE BETTER SHEAR AND COOLER
TEMPERATURES ALOFT COME ON THURSDAY WITH PLENTY OF INSTABILITY
AROUND BOTH DAYS. WILL HAVE TO CONTINUE TO MONITOR THE FORECAST FOR
THIS TIME PERIOD. TEMPERATURES SHOULD BE RIGHT AROUND TO JUST BELOW
NORMAL FOR LATE AUGUST.
FRIDAY AND SATURDAY...HIGH PRESSURE BUILDS INTO THE REGION AND WITH
IT COMES WARMER TEMPERATURES AS WELL. SOUTHWESTERLY TO WESTERLY
DOWNSLOPING FLOW WILL RESULT IN TEMPERATURES WELL ABOVE NORMAL
BRINGING ONE MORE SHOT OF SUMMER LIKE WEATHER TO THE AREA.
SUNDAY AND MONDAY...STRONG LOW PRESSURE MOVES THROUGH QUEBEC TO THE
MARITIMES BRINGING A COLD FRONT ACROSS SOUTHERN NEW ENGLAND MONDAY.
SHOWERS AND THUNDERSTORMS ARE POSSIBLE AHEAD OF THIS FRONT WITH THE
HEAT AND HUMIDITY STILL IN PLACE. MUCH OF THIS WILL DEPEND ON THE
SPEED OF THE FRONT...AMONG OTHER THINGS.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH TUESDAY NIGHT/...MODERATE CONFIDENCE.
TONIGHT...CIGS/VSBYS LOWER TO MVFR-IFR. EXPECT SHOWERS/SCT TSTMS
WITH LOCALLY HEAVY RAINFALL. SW WIND GUSTS UP TO 25 KT THROUGH
02-03Z ALONG S COAST.
TUESDAY...MVFR-IFR CIGS/VSBYS EARLY...SLOWLY IMPROVING TO VFR
FROM W-E. MVFR CIGS/VSBYS MAY LINGER ALONG E COAST THROUGH THE
DAY.
TUESDAY NIGHT...MAINLY VFR EARLY. CIGS LOWERING TO MVFR-IFR
MAINLY ACROSS E MA/RI. VSBYS LOWER TO MVFR-IFR IN PATCHY FOG.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WINDS BECOME LIGHT
ONSHORE LATE TONIGHT/TUE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
WEDNESDAY AND THURSDAY...MODERATE CONFIDENCE. MAINLY VFR.
MVFR/IFR CONDITIONS LIKELY IN ANY SHOWERS AND THUNDERSTORMS THAT
DEVELOP ALONG WITH POSSIBLE FOG WEDNESDAY NIGHT.
FRIDAY AND SATURDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE.
HAVE KEPT SMALL CRAFTS THROUGH TUESDAY. SW WIND GUSTS UP TO 25
KT ACROSS THE SOUTHERN WATERS THROUGH AROUND MIDNIGHT WILL
DIMINISH. ALREADY NOTING SEAS UP TO 6 FT AT SEVERAL OF THE
SOUTHERN BUOYS WHICH WILL SLOWLY SUBSIDE TUESDAY.
WILL SEE INCREASING CHANCE FOR SHOWERS/TSTMS TONIGHT AS WEAK LOW
PRES MOVES TOWARD THE WATERS. WILL SEE REDUCED VSBYS IN ANY
PRECIP ALONG WITH PATCHY FOG DEVELOPING. VSBYS WILL IMPROVE BY
AROUND MIDDAY TUESDAY AS THE FOG DISSIPATES AND PRECIP MOVES
OFFSHORE. WILL LIKELY SEE FOG REDEVELOP TUE NIGHT.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
WHILE WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT CRITERIA FROM
MID WEEK THROUGH THE END OF THE WEEK...THERE IS POTENTIAL FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY AND THURSDAY. ALSO
VISIBILITIES MAY BE LIMITED WEDNESDAY NIGHT IN PATCHY FOG.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
ANZ231>234.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT TUESDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...RLG/EVT
NEAR TERM...NOCERA/RLG/EVT
SHORT TERM...EVT
LONG TERM...RLG
AVIATION...RLG/EVT
MARINE...RLG/EVT
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
340 PM EDT SUN AUG 25 2013
.SYNOPSIS...19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS MUCH OF THE
CENTRAL AND EASTERN PORTIONS OF THE CONUS UNDER THE DOMAIN OF A
LARGE AND AMPLIFIED UPPER LEVEL RIDGE. THIS RIDGE CENTER/AXIS EXIST
NEAR AND JUST TO THE WEST OF THE MIDDLE MS VALLEY. FURTHER
DOWNSTREAM... LONGWAVE TROUGHING HAS EXITED THE EASTERN SEABOARD
WITH A WEAK EXTENSION OF THE TROUGH AXIS BACK TO THE SOUTHWEST
TOWARD THE FLORIDA PENINSULA. WV IMAGERY STILL SHOWS PLENTY OF
MID/HIGH LEVEL MOISTURE IN PLACE OVER THE PENINSULA...BUT AN AREA OF
MUCH DRIER AIR ALOFT AND DECENT SYNOPTIC SUPPRESSION CAN BE SEEN
OVER THE CAROLINAS/GEORGIA. THIS SYNOPTIC SETUP IS CURRENTLY MAKING
A VERY SLOW PUSH INTO NORTHERN FLORIDA...BUT GLOBAL GUIDANCE AGREES
ON A MORE SIGNIFICANT PUSH SOUTHWARD DOWN THE PENINSULA OCCURRING
LATER TONIGHT AND MONDAY MORNING. THIS ACTION WILL SCOUR OUT THE
DEEPER MOISTURE AND ALONG WITH INCREASING ANTI-CYCLONIC FLOW
ALOFT/DEEP LAYER SUPPRESSION WILL HELP TO BRING OUR RAIN CHANCES
BACK DOWN TO CLIMO NORMS...OR LESS...FOR THE EARLY PORTION OF THE
UPCOMING WORK WEEK.
AT THE SURFACE...STRONG RIDGE OF HIGH PRESSURE IS CENTERED OVER THE
MID-ATLANTIC/CAROLINAS AND WILL PROVIDE A NE TO EAST LOW LEVEL FLOW
THROUGH THE PERIOD AS IT SLOWLY SINKS SOUTH AND BEGINS TO WEAKEN.
&&
.SHORT TERM (TONIGHT THROUGH TUESDAY)...
LEFTOVER MID/LATE EVENING STORMS WILL SHIFT/RE-DEVELOP OFFSHORE
AFTER MIDNIGHT LEAVING THE LAND ZONES GENERALLY DRY AFTER 02-03Z.
THE LESS FAVORABLE CONDITIONS (FOR DEEP CONVECTION) PUSHING SOUTH
MAY KEEP THE BEST OFFSHORE STORM COVERAGE TO THE SOUTH OF TAMPA BAY
LATE TONIGHT INTO MONDAY MORNING...AND THIS CONTINUES TO BE A THEME
IN MANY OF THE LARGER SCALE PARAMETRIZED 12Z GUIDANCE.
MONDAY/MONDAY NIGHT...
DEEPER MOISTURE IS SHOWN TO EXIT SOUTH OF LEE/CHARLOTTE COUNTIES BY
EARLY AFTERNOON ALONG WITH THE LINGERING SYNOPTIC SUPPORT FROM THE
UPPER TROUGH. GFS IS ACTUALLY SHOWING SOME RATHER IMPRESSIVE DEEP
LAYER Q-VECTOR DIVERGENCE OVER THE REGION TOMORROW...WHICH WILL WORK
AGAINST ANOTHER ABNORMALLY WET AFTERNOON/EVENING. GIVEN THE FORECAST
ATMOSPHERIC COLUMN...A MORE CLIMO CHANCE POP (40-50%) STORM COVERAGE
CAN BE EXPECTED SOUTH OF I-4. WAS ORIGINALLY THINKING ONLY ISOLATED
/ SLIGHT CHANCE POPS FOR THE NATURE COAST...HOWEVER LATEST GUIDANCE
HAS A BIT MORE ATLANTIC MOISTURE IN THE LOWER TROP GETTING INTO THE
MIX FOR THESE NORTHERN ZONES. THEREFORE WILL KEEP POPS IN THE CHANCE
RANGE 30-40% FOR THE NATURE COAST...HOWEVER SHOWERS OVER THESE
NORTHERN COUNTIES ARE LIKELY TO BE MORE SHALLOW AND BRIEF IN NATURE
/ LIFE CYCLE DUE TO THE DRIER AIR ALOFT. THIS SHOULD LIMIT THE
RAINFALL QPF POTENTIAL...WHICH IS GOOD NEWS FOR AREAS THAT NEED SOME
TIME TO DRY OUT FROM THE SIGNIFICANT RAINFALL OF THE PAST SEVERAL
DAYS.
EVEN THE LOWER LEVEL ATLANTIC MOISTURE LOOKS NOW TO BE SCOURED OUT
MONDAY NIGHT WHICH SHOULD LEAD TO A DRY OVERNIGHT PERIOD AFTER ANY
ISOLATED MID EVENING SHOWERS PUSH OFFSHORE / DIMINISH. THE DRIER
COLUMN AND CLEARING SKIES MAY ALSO ALLOW FOR SOME "COOLER"
OVERNIGHT LOWS BY DAWN. WOULD NOT BE SURPRISED TO SEE PORTIONS OF
THE NATURE COAST AND INLAND SOUTH-CENTRAL ZONES REACH THE UPPER
60S. BREAK OUT THE COATS!
TUESDAY...
THE DRIER COLUMN IS WELL ENTRENCHED FOR THE AFTERNOON. DURING THE
FORECAST PROCESS YESTERDAY...WAS CONCERNED WITH THE INFLUENCE OF AN
UPPER LOW THAT THE GFS WAS TRYING TO CLOSE OFF NEAR THE SW FLORIDA
COAST. LAST COUPLE OF GFS RUNS HAVE COME AROUND MORE TO THE ECMWF
SOLUTION...WHICH IS LATER AND LOCATED CLOSER TO THE BAHAMAS. THIS
TREND SUGGESTS THAT THIS FEATURE WILL HAVE LITTLE INFLUENCE ON OUR
LOCAL WEATHER THROUGH THE SHORT TERM PERIOD (IF EVER). WILL STILL
HAVE LIGHT EASTERLY FLOW ON TUESDAY WHICH GENERALLY IS FAVORABLE FOR
CONVECTION ALONG THE FL WEST COAST. HOWEVER...GIVEN THE DRY COLUMN
ALOFT AND GENERAL ANTI-CYCLONIC NATURE OF THE FLOW ALOFT...WILL KEEP
THE TYPICAL SPATIAL POP PATTERN FOR CONVECTION IN EASTERLY
FLOW...BUT DROP THE RAIN CHANCES DOWN CLOSER TO THE ECMWF MOS
GUIDANCE NUMBERS. DESPITE THE DRIER AIR...THE GFS MOS NUMBERS SEEM
TOO LOW FOR EASTERLY FLOW AND WILL DISREGARD FOR NOW.
AFTERNOON/EVENING RAIN CHANCES WILL FEATURE 30-40% SOUTH OF TAMPA
BAY...AND 20-30% FOR THE I-4 CORRIDOR NORTHWARD ALONG THE NATURE
COAST...WHERE THE PROXIMITY TO THE UPPER RIDGE WILL PROVIDE THE
GREATEST DEGREE OF SYNOPTIC SUPPRESSION.
&&
.LONG TERM (WEDNESDAY-SUNDAY)...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT SHOWING THE HIGH PRESSURE
RIDGE AXIS ACROSS NORTH FLORIDA TO START THE DAY WEDNESDAY...WITH
THE AXIS SHIFTING STEADILY SOUTHWARD INTO SOUTH FLORIDA BY FRIDAY
EVENING. THE RIDGE AXIS WILL REMAIN ACROSS SOUTH FLORIDA AND THE
FLORIDA STRAIGHTS OVER THE UPCOMING WEEKEND AS A TROUGH OF LOW
PRESSURE STALLS OUT ALONG THE NORTHERN GULF COAST. OVERALL...EXPECT
ISOLATED/SCATTERED MAINLY AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS WEDNESDAY THROUGH FRIDAY. SHOULD SEE AN INCREASE IN
SHOWER/THUNDERSTORM COVERAGE OVER THE UPCOMING WEEKEND AS DEEPER
MOISTURE ASSOCIATED WITH THE TROUGH OF LOW PRESSURE PUSHES SOUTHWARD
INTO THE AREA. TEMPERATURES ARE EXPECTED TO RUN CLOSE TO CLIMO
THROUGH THE LONG TERM PERIODS.
&&
.AVIATION...
BKN MID/HIGH CLOUDS THROUGH THE EVENING...WITH VCNTY TSRA UNTIL 02Z.
BETWEEN 21Z-00Z TEMPO MVFR VSBY/CIG IN TSRA WITH LCL IFR PSBL. HIGH
PRESSURE BUILDING IN TO THE NORTH WILL PROVIDE AN E-NE
FLOW...KEEPING THE SEA BREEZE CLOSE TO THE COAST THIS
AFTERNOON...THROUGH MON.
&&
.MARINE...
A STRONG RIDGE OF HIGH PRESSURE CURRENTLY CENTERED NEAR THE
MID-ATLANTIC STATES WILL SLOWLY WEAKEN AS IT SETTLES SOUTHWARD
TOWARD THE EASTERN GULF OF MEXICO DURING THE NEXT SEVERAL DAYS. THE
POSITION OF THIS RIDGE WILL BE FAVORABLE THE NEXT COUPLE OF NIGHTS
FOR ENHANCED EASTERLY FLOW THAT WILL LINGER INTO THE EARLY MORNING
HOURS. WINDS WILL BE STRONGEST AND POTENTIALLY APPROACH CAUTIONARY
LEVELS AT TIMES TO THE NORTH OF TARPON SPRINGS. BY MIDWEEK THE
RIDGE WILL APPROACH THE AREA ALLOW THE GRADIENT AND RESULTING WINDS
TO DIMINISH WELL BELOW HEADLINE CRITERIA.
&&
.FIRE WEATHER...
HIGH PRESSURE WELL TO OUR NORTH WILL SLOWLY SLIDE SOUTHWARD THROUGH
THE EARLY PORTION OF THE WEEK. DRIER AIR ALOFT WILL RESULT IN A MORE
TYPICAL DISTRIBUTION OF AFTERNOON AND EVENING STORMS THE NEXT
SEVERAL DAYS COMPARED TO THE WIDESPREAD ACTIVITY SEEN IN PAST DAYS.
DESPITE THE DRIER AIR ALOFT...NO SIGNIFICANT PUSH OF DRIER AIR IN
THE LOWER LEVELS IS EXPECTED AND RELATIVE HUMIDITY VALUES ARE
FORECAST TO REMAIN WELL ABOVE CRITICAL LEVELS. AT THIS TIME...NO
SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH THE MIDDLE
OF THE WEEK.
&&
.HYDROLOGY...
THE CYPRESS CREEK AT WORTHINGTON GARDENS IS THE ONLY RIVER CURRENTLY
EXPECTED TO REACH FLOOD STAGE. AS OF 3PM...WATER LEVEL IS AT 7.4
FEET WITH FLOOD STAGE REACHED AT 8 FEET. THE RIVER IS EXPECTED TO
REACH FLOOD STAGE LATE IN THE DAY ON MONDAY OR EARLY TUESDAY. WATER
LEVELS ON THE HORSE CREEK NEAR ARCADIA REMAIN HIGH...BUT THE RIVER
IS EXPECTED TO STAY JUST BELOW FLOOD STAGE OVER THE NEXT FEW DAYS.
HOWEVER ANY HEAVY PERSISTENT RAINFALL FROM AFTERNOON SHOWERS AND
THUNDERSTORMS OVER THESE BASINS COULD CAUSE WATER LEVELS TO RISE
MORE THAN CURRENTLY FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 90 75 91 / 30 40 20 30
FMY 74 90 73 91 / 30 50 30 40
GIF 72 91 72 92 / 20 40 20 30
SRQ 74 90 74 91 / 30 40 30 30
BKV 71 90 70 91 / 20 40 20 30
SPG 77 90 78 90 / 30 40 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM...JELSEMA
AVIATION...RUDE
HYDROLOGY...MCKAUGHAN
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1105 AM EDT SUN AUG 25 2013
.LATE MORNING UPDATE...
OVERALL CLOUD COVER IS A BIT MORE ROBUST THAN ORIGINALLY EXPECTED
THANKS IN PART TO CONVECTIVE BLOW-OFF FROM ALL THE STORMS
OFFSHORE THIS MORNING. HAVE LOWERED HIGH TEMPS A COUPLE OF DEGREES
TO ACCOUNT FOR THE PARTIAL LOSS OF INSOLATION DURING THESE PEAK
HEATING HOURS. THE WEAKER HEATING MAY ALSO HAVE A NEGATIVE IMPACT ON
THE STRENGTH OF THE SEA-BREEZE. UPPER 80S WATER TEMPS AND UPPER 80S
TEMPS DON`T LEAD TO MUCH OF A DISCONTINUITY. WILL HAVE TO SEE JUST
HOW ANY LOSS OF SEA-BREEZE STRENGTH WILL IMPACT THE AFTERNOON
CONVECTION. SURE THERE ARE STILL PLENTY OF RESIDUAL BOUNDARIES OUT
THERE FROM ALL THE ACTIVITY THE PAST FEW DAYS TO GET SOME ACTIVITY
GOING...BUT THE LOSS OR WEAKNESS OF THIS MAIN MECHANISM WOULD LIKELY
HAVE A NEGATIVE IMPACT ON THE FOCUS FOR RISING MOTION. AT THE VERY
LEAST WOULD EXPECT A TEMPORAL DELAY IN GOOD CONVECTIVE COVERAGE
COMPARED TO PREVIOUS DAYS.
&&
.MID MORNING UPDATE (REST OF TODAY THROUGH MONDAY)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS MUCH OF THE CENTRAL AND
EASTERN PORTIONS OF THE CONUS UNDER THE DOMAIN OF A LARGE AND
AMPLIFIED UPPER LEVEL RIDGE. THIS RIDGE CENTER/AXIS EXIST NEAR AND
JUST TO THE WEST OF THE MIDDLE MS VALLEY. FURTHER DOWNSTREAM...
LONGWAVE TROUGHING HAS EXITED THE EASTERN SEABOARD WITH A WEAK
EXTENSION OF THE TROUGH AXIS BACK TO THE SOUTHWEST TOWARD THE
FLORIDA PENINSULA. WV IMAGERY STILL SHOWS PLENTY OF MID/HIGH LEVEL
MOISTURE IN PLACE OVER THE PENINSULA TODAY...BUT AN AREA OF MUCH
DRIER AIR ALOFT AND DECENT SYNOPTIC SUPPRESSION CAN BE SEEN OVER THE
CAROLINAS/GEORGIA. THIS SYNOPTIC SETUP WILL MAKE A PUSH INTO
NORTHERN FLORIDA LATER TODAY...BUT GLOBAL GUIDANCE AGREES ON A MORE
SIGNIFICANT PUSH SOUTHWARD DOWN THE PENINSULA OCCURRING TONIGHT AND
MONDAY MORNING. THIS ACTION WILL SCOUR OUT THE DEEPER MOISTURE AND
ALONG WITH INCREASING ANTI-CYCLONIC FLOW ALOFT/DEEP LAYER
SUPPRESSION WILL HELP TO BRING OUR RAIN CHANCES BACK DOWN TO CLIMO
NORMS...OR LESS...FOR THE EARLY PORTION OF THE UPCOMING WORK WEEK.
AT THE SURFACE...STRONG RIDGE OF HIGH PRESSURE IS CENTERED OVER THE
MID-ATLANTIC/CAROLINAS AND WILL PROVIDE A NE TO EAST LOW LEVEL FLOW
THROUGH THE PERIOD AS IT SLOWLY SINKS SOUTH AND BEGINS TO WEAKEN.
REST OF TODAY...WELL DEFINED LAND BREEZE AIDED BY THE SYNOPTIC E/NE
FLOW IS RESULTING IN PLENTY OF LOW LEVEL CONVERGENCE OFFSHORE THIS
MORNING. THIS CONVERGENCE ALONG WITH THE DEEP MOISTURE AND WEAK
SYNOPTIC SUPPORT FOR LIFT OVERHEAD IS MAKING FOR AN ACTIVE MORNING
IN TERMS OF THUNDERSTORMS AWAY FROM THE COAST. MARINERS STAYING
CLOSE TO THE COAST THIS MORNING SHOULD BE OK...BUT ANYONE PLANNING
TO GO FURTHER OFFSHORE BEYOND 15-20 MILES SHOULD EXPECT THE
OCCASIONAL ROUGHER WEATHER. THIS ACTIVITY WILL WEAKEN/DIMINISH
SOMEWHAT INTO THE AFTERNOON AS THE LAND-BREEZE COLLAPSES.
HOWEVER...DUE TO THE FAVORABLE ENVIRONMENT ALOFT...PROB WILL NOT
COMPLETELY DISAPPEAR AS OFTEN HAPPENS IN THE SUMMER.
BIT OF A DIFFICULT FORECAST PATTERN FOR THE LAND ZONES...ESPECIALLY
FOR THOSE AREA NORTH OF TAMPA BAY. LESS FAVORABLE ATMOSPHERIC
CONDITIONS TO SUPPORT NUMEROUS STORMS WILL BE SLIDING SOUTH TOWARD
THE AREA DURING THE DAY...BUT IT IS BE A CLOSE CALL WHETHER IT
ARRIVES IN TIME THIS AFTERNOON TO REALLY MAKE AN IMPACT FOR PLACES
LIKE LEVY/CITRUS/SUMTER/HERNANDO. THERE CERTAINLY WILL BE A DECREASE
IN DEEP MOISTURE FOR THESE AREA BY LATE IN THE DAY...HOWEVER THESE
MOISTURE/PW GRADIENTS CAN ALSO BE THE FOCUS FOR CONVECTIVE ACTIVITY.
WITH THIS IN MIND...WILL NOT GET TOO DETAILED WITH THE FORECAST AND
KEEP CHANCE POP WORDING NORTH OF TAMPA BAY...AND LIKELY POP WORDING
FURTHER SOUTH WITHIN THE ZONE OF DEEPEST MOISTURE AND UPPER LEVEL
TROUGH SUPPORT.
MID-LEVEL LAPSE RATES ARE NOTHING IMPRESSIVE TODAY WHICH SHOULD KEEP
THE CHANCES FOR SEVERE STORMS GENERALLY DOWN. HOWEVER...ONCE AGAIN
THE CONCERN WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINS OVER
SATURATED SOILS DUE TO WEAK WIND FIELDS AND RESULTING SLOW STORM
MOTION. WE DO HAVE SOME STRONGER FLOW TOWARD THE TOP OF THE TROP
TODAY...BUT ONLY THE TALLEST OF STORMS WILL REALLY BE ABLE TO FEEL
THIS IMPACT...WITH THE MAJORITY OF THE STORMS MASS COLUMN DEVELOPING
WITHIN A WEAK FLOW PATTERN.
EVENING STORMS WILL SHIFT/RE-DEVELOP OFFSHORE AFTER MIDNIGHT LEAVING
THE LAND ZONES GENERALLY DRY AFTER 02-03Z. THE LESS FAVORABLE
CONDITIONS (FOR DEEP CONVECTION) PUSHING SOUTH MAY KEEP THE BEST
OFFSHORE STORM COVERAGE TO THE SOUTH OF TAMPA BAY LATE TONIGHT INTO
MONDAY MORNING COMPARED TO TODAY...AND THIS SEEMS TO BE A THEME IN
MANY OF THE LARGER SCALE PARAMETRIZED GUIDANCE.
MONDAY...
DEEPER MOISTURE IS SHOWN TO EXIT SOUTH OF LEE/CHARLOTTE COUNTIES BY
EARLY AFTERNOON ALONG WITH THE LINGERING SYNOPTIC SUPPORT FROM THE
UPPER TROUGH. GFS IS ACTUALLY SHOWING SOME RATHER IMPRESSIVE
Q-VECTOR DIVERGENCE OVERHEAD FOR MUCH OF THE REGION TOMORROW
WHICH WILL WORK AGAINST ANOTHER ABNORMALLY WET AFTERNOON/EVENING.
WILL BE CURIOUS TO SEE WHAT KIND OF POPS COME OUT WITH THE 12Z
PACKAGE...BUT CAN NOT SEE GOING ANY HIGHER THAN WHAT IS CURRENTLY IN
THE GRIDS. GIVEN THE FORECAST ATMOSPHERIC COLUMN...A MORE CLIMO
CHANCE POP (40-50%) TYPE STORM COVERAGE CAN BE EXPECTED SOUTH OF
I-4...AND BELOW CLIMO (20-30%) POP COVERAGE FURTHER NORTH THROUGH
THE NATURE COAST.
ENJOY YOUR SUNDAY!
&&
.AVIATION...
LOW CIGS AND PATCHY BR AVOIDED THE TAF TERMINALS THIS MORNING.
OTHERWISE EXPECT VFR UNTIL THIS AFTERNOON WHEN VCNTY SHRA/TSRA FORM
DURING A 19Z-02Z WINDOW...WITH SOME TEMPO MVFR/LCL IFR PSBL. HIGH
PRESSURE BUILDING IN TO THE NORTH WILL PROVIDE A NE FLOW THAT KEEPS
THE AFTERNOON SEA BREEZE CLOSE TO THE COAST.
&&
.MARINE...
A STRONG RIDGE OF HIGH PRESSURE WELL TO OUR NORTH ALONG THE
MID-ATLANTIC STATES WILL PROVIDE AN EASTERLY WIND FLOW THROUGH THE
EARLY NEXT WEEK. THE GRADIENT IS EXPECTED TO RELAX ENOUGH THIS
AFTERNOON TO PROVIDE FOR AN ONSHORE SEA BREEZE TO DEVELOP. THE RIDGE
TO OUR NORTH WILL TAKE A POSITION BY TONIGHT AND MONDAY NIGHT TO
PROVIDE ENHANCED EASTERLY FLOW EACH NIGHT INTO THE EARLY MORNING
HOURS. WINDS MAY AT TIMES APPROACH CAUTIONARY LEVELS...ESPECIALLY TO
THE NORTH OF TARPON SPRINGS.
&&
.FIRE WEATHER...
NO CONCERNS OVERALL. SOME PATCHY GROUND FOG IS POSSIBLE AROUND
SUNRISE EACH DAY IN NORMALLY FOG-PRONE AREAS AND THOSE THAT
RECEIVE RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 75 90 75 / 60 40 30 30
FMY 89 73 88 72 / 60 40 60 20
GIF 90 72 90 72 / 60 30 40 30
SRQ 88 74 89 73 / 60 40 40 30
BKV 89 71 91 69 / 50 40 20 20
SPG 88 76 89 77 / 60 40 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
915 AM EDT SUN AUG 25 2013
.UPDATE (REST OF TODAY THROUGH MONDAY)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS MUCH OF THE CENTRAL AND
EASTERN PORTIONS OF THE CONUS UNDER THE DOMAIN OF A LARGE AND
AMPLIFIED UPPER LEVEL RIDGE. THIS RIDGE CENTER/AXIS EXIST NEAR AND
JUST TO THE WEST OF THE MIDDLE MS VALLEY. FURTHER DOWNSTREAM...
LONGWAVE TROUGHING HAS EXITED THE EASTERN SEABOARD WITH A WEAK
EXTENSION OF THE TROUGH AXIS BACK TO THE SOUTHWEST TOWARD THE
FLORIDA PENINSULA. WV IMAGERY STILL SHOWS PLENTY OF MID/HIGH LEVEL
MOISTURE IN PLACE OVER THE PENINSULA TODAY...BUT AN AREA OF MUCH
DRIER AIR ALOFT AND DECENT SYNOPTIC SUPPRESSION CAN BE SEEN OVER THE
CAROLINAS/GEORGIA. THIS SYNOPTIC SETUP WILL MAKE A PUSH INTO
NORTHERN FLORIDA LATER TODAY...BUT GLOBAL GUIDANCE AGREES ON A MORE
SIGNIFICANT PUSH SOUTHWARD DOWN THE PENINSULA OCCURRING TONIGHT AND
MONDAY MORNING. THIS ACTION WILL SCOUR OUT THE DEEPER MOISTURE AND
ALONG WITH INCREASING ANTI-CYCLONIC FLOW ALOFT/DEEP LAYER
SUPPRESSION WILL HELP TO BRING OUR RAIN CHANCES BACK DOWN TO CLIMO
NORMS...OR LESS...FOR THE EARLY PORTION OF THE UPCOMING WORK WEEK.
AT THE SURFACE...STRONG RIDGE OF HIGH PRESSURE IS CENTERED OVER THE
MID-ATLANTIC/CAROLINAS AND WILL PROVIDE A NE TO EAST LOW LEVEL FLOW
THROUGH THE PERIOD AS IT SLOWLY SINKS SOUTH AND BEGINS TO WEAKEN.
REST OF TODAY...WELL DEFINED LAND BREEZE AIDED BY THE SYNOPTIC E/NE
FLOW IS RESULTING IN PLENTY OF LOW LEVEL CONVERGENCE OFFSHORE THIS
MORNING. THIS CONVERGENCE ALONG WITH THE DEEP MOISTURE AND WEAK
SYNOPTIC SUPPORT FOR LIFT OVERHEAD IS MAKING FOR AN ACTIVE MORNING
IN TERMS OF THUNDERSTORMS AWAY FROM THE COAST. MARINERS STAYING
CLOSE TO THE COAST THIS MORNING SHOULD BE OK...BUT ANYONE PLANNING
TO GO FURTHER OFFSHORE BEYOND 15-20 MILES SHOULD EXPECT THE
OCCASIONAL ROUGHER WEATHER. THIS ACTIVITY WILL WEAKEN/DIMINISH
SOMEWHAT INTO THE AFTERNOON AS THE LAND-BREEZE COLLAPSES.
HOWEVER...DUE TO THE FAVORABLE ENVIRONMENT ALOFT...PROB WILL NOT
COMPLETELY DISAPPEAR AS OFTEN HAPPENS IN THE SUMMER.
BIT OF A DIFFICULT FORECAST PATTERN FOR THE LAND ZONES...ESPECIALLY
FOR THOSE AREA NORTH OF TAMPA BAY. LESS FAVORABLE ATMOSPHERIC
CONDITIONS TO SUPPORT NUMEROUS STORMS WILL BE SLIDING SOUTH TOWARD
THE AREA DURING THE DAY...BUT IT IS BE A CLOSE CALL WHETHER IT
ARRIVES IN TIME THIS AFTERNOON TO REALLY MAKE AN IMPACT FOR PLACES
LIKE LEVY/CITRUS/SUMTER/HERNANDO. THERE CERTAINLY WILL BE A DECREASE
IN DEEP MOISTURE FOR THESE AREA BY LATE IN THE DAY...HOWEVER THESE
MOISTURE/PW GRADIENTS CAN ALSO BE THE FOCUS FOR CONVECTIVE ACTIVITY.
WITH THIS IN MIND...WILL NOT GET TOO DETAILED WITH THE FORECAST AND
KEEP CHANCE POP WORDING NORTH OF TAMPA BAY...AND LIKELY POP WORDING
FURTHER SOUTH WITHIN THE ZONE OF DEEPEST MOISTURE AND UPPER LEVEL
TROUGH SUPPORT.
MID-LEVEL LAPSE RATES ARE NOTHING IMPRESSIVE TODAY WHICH SHOULD KEEP
THE CHANCES FOR SEVERE STORMS GENERALLY DOWN. HOWEVER...ONCE AGAIN
THE CONCERN WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINS OVER
SATURATED SOILS DUE TO WEAK WIND FIELDS AND RESULTING SLOW STORM
MOTION. WE DO HAVE SOME STRONGER FLOW TOWARD THE TOP OF THE TROP
TODAY...BUT ONLY THE TALLEST OF STORMS WILL REALLY BE ABLE TO FEEL
THIS IMPACT...WITH THE MAJORITY OF THE STORMS MASS COLUMN DEVELOPING
WITHIN A WEAK FLOW PATTERN.
EVENING STORMS WILL SHIFT/RE-DEVELOP OFFSHORE AFTER MIDNIGHT LEAVING
THE LAND ZONES GENERALLY DRY AFTER 02-03Z. THE LESS FAVORABLE
CONDITIONS (FOR DEEP CONVECTION) PUSHING SOUTH MAY KEEP THE BEST
OFFSHORE STORM COVERAGE TO THE SOUTH OF TAMPA BAY LATE TONIGHT INTO
MONDAY MORNING COMPARED TO TODAY...AND THIS SEEMS TO BE A THEME IN
MANY OF THE LARGER SCALE PARAMETRIZED GUIDANCE.
MONDAY...
DEEPER MOISTURE IS SHOWN TO EXIT SOUTH OF LEE/CHARLOTTE COUNTIES BY
EARLY AFTERNOON ALONG WITH THE LINGERING SYNOPTIC SUPPORT FROM THE
UPPER TROUGH. GFS IS ACTUALLY SHOWING SOME RATHER IMPRESSIVE
Q-VECTOR DIVERGENCE OVERHEAD FOR MUCH OF THE REGION TOMORROW
WHICH WILL WORK AGAINST ANOTHER ABNORMALLY WET AFTERNOON/EVENING.
WILL BE CURIOUS TO SEE WHAT KIND OF POPS COME OUT WITH THE 12Z
PACKAGE...BUT CAN NOT SEE GOING ANY HIGHER THAN WHAT IS CURRENTLY IN
THE GRIDS. GIVEN THE FORECAST ATMOSPHERIC COLUMN...A MORE CLIMO
CHANCE POP (40-50%) TYPE STORM COVERAGE CAN BE EXPECTED SOUTH OF
I-4...AND BELOW CLIMO (20-30%) POP COVERAGE FURTHER NORTH THROUGH
THE NATURE COAST.
ENJOY YOUR SUNDAY!
&&
.AVIATION...
LOW CIGS AND PATCHY BR AVOIDED THE TAF TERMINALS THIS MORNING.
OTHERWISE EXPECT VFR UNTIL THIS AFTERNOON WHEN VCNTY SHRA/TSRA FORM
DURING A 19Z-02Z WINDOW...WITH SOME TEMPO MVFR/LCL IFR PSBL. HIGH
PRESSURE BUILDING IN TO THE NORTH WILL PROVIDE A NE FLOW THAT KEEPS
THE AFTERNOON SEA BREEZE CLOSE TO THE COAST.
&&
.MARINE...
A STRONG RIDGE OF HIGH PRESSURE WELL TO OUR NORTH ALONG THE
MID-ATLANTIC STATES WILL PROVIDE AN EASTERLY WIND FLOW THROUGH THE
EARLY NEXT WEEK. THE GRADIENT IS EXPECTED TO RELAX ENOUGH THIS
AFTERNOON TO PROVIDE FOR AN ONSHORE SEA BREEZE TO DEVELOP. THE RIDGE
TO OUR NORTH WILL TAKE A POSITION BY TONIGHT AND MONDAY NIGHT TO
PROVIDE ENHANCED EASTERLY FLOW EACH NIGHT INTO THE EARLY MORNING
HOURS. WINDS MAY AT TIMES APPROACH CAUTIONARY LEVELS...ESPECIALLY TO
THE NORTH OF TARPON SPRINGS.
&&
.FIRE WEATHER...
NO CONCERNS OVERALL. SOME PATCHY GROUND FOG IS POSSIBLE AROUND
SUNRISE EACH DAY IN NORMALLY FOG-PRONE AREAS AND THOSE THAT
RECEIVE RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 75 90 75 / 60 40 30 30
FMY 89 73 88 72 / 60 40 60 20
GIF 90 72 90 72 / 60 30 40 30
SRQ 88 74 89 73 / 60 40 40 30
BKV 89 71 91 69 / 50 40 20 20
SPG 88 76 89 77 / 60 40 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS BOISE ID
914 PM MDT MON AUG 26 2013
.DISCUSSION...DEEPER MONSOON MOISTURE IS WELL DEFINED ON EVENING
SATELLITE PICS...ARCING FROM THE DESERT SW...THROUGH S-CENTRAL
IDAHO AND INTO W-CENTRAL MT. THE CLOUD COVER LIKELY CAPPED THE
ATMOSPHERE THIS AFTERNOON LIMITING CONVECTIVE ACTIVITY TO MOSTLY
CUMULUS BUILDUPS AND A FEW SHOWERS OVER THE BOISE MTNS. THE 18Z
MODELS INITIALIZED TO FAR SOUTH AND EAST WITH THIS MOISTURE
PLUME...THOUGH RECENT RUNS OF THE HRRR MODEL HAVE CAPTURED IT
AND SHOW THE CLOUDS PULLING EAST EARLY TUESDAY MORNING. ONLY
CHANGE TO THE FORECAST FOR TONIGHT WAS AN INCREASE IN CLOUD COVER
OVER S-CENTRAL IDAHO ZONES. THE RIM FIRE AMONG OTHERS IN CENTRAL
CA CONTINUED TO PUMP OUT THE SMOKE TODAY...SO NO MAJOR CHANGES
IN SMOKEY/HAZY CONDITIONS IN THE NEXT 24 HOURS.
&&
.AVIATION...VFR. SMOKE FROM CALIFORNIA FIRES WILL CONTINUE TO MOVE
OVER THE AREA WITH SMOKE LAYERS AOA 10K FT AND WILL PERSIST THROUGH
WEDNESDAY. ISOLATED THUNDERSTORMS WILL DEVELOP TUESDAY AFTERNOON AND
EVENING. AND ON WEDNESDAY SCATTERED THUNDERSTORMS WILL DEVELOP.
THUNDERSTORMS WILL IMPACT THE FOLLOWING AREAS...MOUNTAINS OF SW IDAHO
AND THE WESTERN MAGIC VALLEY. SURFACE WINDS SOUTHERLY 5 TO 15 KTS.
WINDS ALOFT SOUTHWEST 20 KTS AT 10K FT MSL.
&&
.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH WEDNESDAY...SHORT WAVE WHICH ROLLED NE
THROUGH OREGON YESTERDAY TEMPORARILY PUSHED THE BULK OF THE MONSOON
MOISTURE TO OUR EAST TODAY. IN ITS WAKE...A DRIER AND MORE STABLE
SOUTHWEST FLOW RESULTED IN JUST SOME SCATTERED CUMULUS CLOUDS ACROSS
SE OREGON AND THE HIGHER TERRAIN OF SW IDAHO SO FAR THIS AFTERNOON.
STILL COULD BE JUST ENOUGH INSTABILITY FOR ISOLATED CONVECTION SOUTH
OF TWIN FALLS AND EAST OF MCCALL AND IDAHO CITY THE REMAINDER OF
THIS AFTERNOON THROUGH THIS EVENING. A MOIST MONSOON SURGE WILL MOVE
INTO SW IDAHO STARTING TUESDAY AND CONTINUING THROUGH WEDNESDAY.
PRECIPITABLE WATER VALUES WILL INCREASE TO WELL ABOVE NORMAL VALUES
ESPECIALLY OVER SOUTH-CENTRAL IDAHO...SOME OF WHICH IS A RESULT OF
REMNANTS FROM IVO. THE COMBINATION OF THE MOISTURE...UPPER LEVEL
SUPPORT WITH JET STREAM WINDS OF AROUND 60 KNOTS...AND INSTABILITY
WILL RESULT IN A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE
MAJORITY OF SOUTHWEST IDAHO. GUSTY WINDS AND LOCALLY HEAVY RAINFALL
WILL ACCOMPANY THE STRONGER STORMS. A DRIER SOUTHWEST FLOW WILL
REMAIN OVER SE OREGON THROUGH WEDNESDAY...WITH THE EXCEPTION OF FAR
SOUTHERN MALHEUR COUNTY WHICH WILL BE NEAR THE EDGE OF THE MONSOON.
TEMPERATURES WILL BE A LITTLE ABOVE NORMAL.
LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...ISOLATED MAINLY
AFTERNOON AND EVENING THUNDERSTORMS WILL CONTINUE THROUGH MONDAY
OVER THE CENTRAL IDAHO AND BOISE MOUNTAINS AND SOUTHWEST IDAHO
HIGHLANDS. THIS WEEKEND AND MONDAY ISOLATED THUNDERSTORMS ARE ALSO
POSSIBLE OVER EASTERN OREGON AS FAR SOUTH AS BAKER AND NORTHERN
HARNEY COUNTIES. THE MORE WESTERLY COMPONENT OF THE UPPER LEVEL FLOW
WILL HINDER THE NORTHWARD PUSH OF MONSOON MOISTURE...SO FUEL FOR
THUNDERSTORMS WILL HAVE TO COME FROM LESS MOIST AND MORE STABLE AIR
FROM OFF THE COAST. ABOVE NORMAL TEMPERATURES WILL PERSIST THROUGH
THE PERIOD...AS THE VERY WARM UPPER LEVEL RIDGE OVER THE SOUTHERN
ROCKIES AND GREAT PLAINS CONTINUES TO HOLD A COOL UPPER LEVEL TROUGH
OFFSHORE. MODEL SOLUTIONS DIFFER CONSIDERABLY ON TIMING THE TROUGH
INLAND...BUT THE ECMWF...WHICH STALLS THE TROUGH ALONG THE NORTHWEST
COAST...LOOKS MOST REASONABLE CONSIDERING THE STRENGTH OF THE RIDGE
AND THE LONG WAVELENGTH AND HIGH AMPLITUDE OF FEATURES OVER THE
NORTH PACIFIC AND NORTH AMERICA.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
EVENING IDZ402-403-421-423-424-426.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...DG
AVIATION.....RD
PREV SHORT TERM...BW
PREV LONG TERM....JT/WH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1121 AM MDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 912 AM MDT SUN AUG 25 2013
DECREASED WINDS A FEW KNOTS FOR THIS AFTERNOON BASED ON WINDS
MIXING DOWN FROM 700MB WHERE THE TOP OF THE MIXED LAYER WILL BE.
SO FAR THE DAY LOOKS VERY SIMILAR TO YESTERDAY. AM A BIT CONCERNED
WITH THE MORE SOUTH-SOUTHWEST DIRECTION OF THE WINDS AS THIS MAY
ALLOW DEW POINTS TO FALL A FEW MORE DEGREES THAN YESTERDAY. SO FAR
LOOKS LIKE WINDS/RELATIVE HUMIDITIES WILL BE VERY CLOSE TO MEETING
CRITICAL FIRE WEATHER CONDITIONS. AT THIS TIME...AND BASED ON WHAT
HAPPENED YESTERDAY...DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY
FIRE WEATHER PRODUCTS FOR THE AFTERNOON. THE RECENT RAINS ALSO ADD
MORE COMPLEXITY TO WHERE THE FUELS WILL BE FAVORABLE FOR RAPID
FIRE GROWTH AND WHERE THEY WONT BE. AT THIS POINT CHEYENNE TO
RAWLINS AND SHERMAN TO THOMAS COUNTIES AND RED WILLOW COUNTY LOOK
TO BE THE MOST FAVORABLE FOR CRITICAL FIRE WEATHER CONDITIONS.
WILL CONTINUE TO MONITOR IN CASE A FIRE WEATHER PRODUCT IS NEEDED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1120 AM MDT SUN AUG 25 2013
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. VERY SIMILAR CONDITIONS
IN PLAY TODAY COMPARED TO YESTERDAY. SOUTHERLY WINDS WILL REMAIN
GUSTY THROUGH THE AFTERNOON AND WELL INTO THE EVENING THEN RETURN
MID TO LATE MORNING MONDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...JJM
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
920 AM MDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 912 AM MDT SUN AUG 25 2013
DECREASED WINDS A FEW KNOTS FOR THIS AFTERNOON BASED ON WINDS
MIXING DOWN FROM 700MB WHERE THE TOP OF THE MIXED LAYER WILL BE.
SO FAR THE DAY LOOKS VERY SIMILAR TO YESTERDAY. AM A BIT CONCERNED
WITH THE MORE SOUTH-SOUTHWEST DIRECTION OF THE WINDS AS THIS MAY
ALLOW DEW POINTS TO FALL A FEW MORE DEGREES THAN YESTERDAY. SO FAR
LOOKS LIKE WINDS/RELATIVE HUMIDITIES WILL BE VERY CLOSE TO MEETING
CRITICAL FIRE WEATHER CONDITIONS. AT THIS TIME...AND BASED ON WHAT
HAPPENED YESTERDAY...DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY
FIRE WEATHER PRODUCTS FOR THE AFTERNOON. THE RECENT RAINS ALSO ADD
MORE COMPLEXITY TO WHERE THE FUELS WILL BE FAVORABLE FOR RAPID
FIRE GROWTH AND WHERE THEY WONT BE. AT THIS POINT CHEYENNE TO
RAWLINS AND SHERMAN TO THOMAS COUNTIES AND RED WILLOW COUNTY LOOK
TO BE THE MOST FAVORABLE FOR CRITICAL FIRE WEATHER CONDITIONS.
WILL CONTINUE TO MONITOR IN CASE A FIRE WEATHER PRODUCT IS NEEDED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 529 AM MDT SUN AUG 25 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK...WITH ONLY PASSING HIGH CLOUDS. BREEZY CONDITIONS WILL
REDEVELOP THIS MORNING AND CONTINUE THROUGH AT LEAST THE EARLY
EVENING HOURS...POSSIBLY INTO THE OVERNIGHT AS TIGHT PRESSURE
GRADIENT REMAINS IN PLACE. STRONGEST WIND GUSTS WILL BE THIS
AFTERNOON WHEN GUSTS 30-35KT WILL BE POSSIBLE AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
531 AM MDT SUN AUG 25 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 529 AM MDT SUN AUG 25 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK...WITH ONLY PASSING HIGH CLOUDS. BREEZY CONDITIONS WILL
REDEVELOP THIS MORNING AND CONTINUE THROUGH AT LEAST THE EARLY
EVENING HOURS...POSSIBLY INTO THE OVERNIGHT AS TIGHT PRESSURE
GRADIENT REMAINS IN PLACE. STRONGEST WIND GUSTS WILL BE THIS
AFTERNOON WHEN GUSTS 30-35KT WILL BE POSSIBLE AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
254 AM MDT SUN AUG 25 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 254 AM MDT SUN AUG 25 2013
LITTLE IS GOING TO CHANGE REGARDING THE THE LARGE SCALE PATTERN
ACROSS THE CENTRAL US...WITH HOT/DRY CONDITIONS EXPECTED OVER OUR
CWA. LARGE H5 RIDGE REMAIN IN PLACE OVER THE CENTRAL CONUS...WITH
LATEST RAP ANALYSIS SHOWS 595DM CENTER ACROSS KS/MO STATE LINE.
GFS/NAM SHOW HEIGHTS CONTINUING TO RISE THROUGH THE DAY WITH
597-598DM CENTER BY 00Z THIS AFTERNOON.
WITH DRY/STABLE AIR MASS IN PLACE PRIMARY CONCERN WILL CONTINUE TO
BE HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS IN THE
WEST. STRONG LEE TROUGH WILL REMAIN IN PLACE THROUGH MONDAY...WITH
STRONG SOUTHERLY PRESSURE GRADIENT OVER OUR CWA. BREEZY TO WINDY
CONDITIONS ARE EXPECTED TODAY THROUGH MONDAY...WITH LATEST GUIDANCE
BEGINNING TO SHOW WINDY CONDITIONS FURTHER WEST WHERE LOWER RH
VALUES WILL BE. AT THIS POINT...IT APPEARS WE WILL BE JUST OUTSIDE
OF RFW CRITERIA FOR RH...THOUGH I COULDNT RULE OUT A FEW WESTERN
LOCATIONS FALLING JUST WITHIN LOCAL CRITERIA. I AM NOT PLANNING ON
ISSUING A WARNING AT THIS TIME DUE TO THE MARGINAL AND ISOLATED
NATURE OF THESE CONDITIONS. THERE IS ALSO A QUESTION REGARDING
FUELS...WITH ISOLATED PARTS OF OUR CWA HAVING RECEIVED QUITE A BIT
OF RAINFALL SINCE LATE JUNE DESPITE THE MAJORITY OF THE AREA
REMAINING IN DROUGHT. SATELLITE DERIVED GREENNESS PRODUCTS SHOW
PREDOMINANTLY GREEN FUELS OVER PARTS OF THE TRI-STATE AREA...THOUGH
THERE ARE PARTS OF MANY COUNTIES THAT FALL BELOW NORMAL GREENNESS
LEVELS. IF CONDITIONS WERE LESS MARGINAL...THE STATUS OF FUELS
MIGHT STILL PREEMPT ISSUANCE OF RFW FOR PARTS OF OUR CWA.
REGARDING HIGH/LOW TEMPS...I USED BIASES FROM SUN AS THE BASIS FOR
THE FORECAST THROUGH TUE WITH VERY SIMILAR AIR MASS IN PLACE EACH
DAY. I ALSO TRENDED LOW TEMPS UP FROM PREVIOUS FORECAST WITH
BREEZY WINDS LIKELY IMPACTING RADIATIONAL COOLING EACH NIGHT.
FORECAST IS STILL CALLING FOR UPPER 90S/LOW 100S EACH
AFTERNOON..AND BY MON/TUE I WOULDNT BE SURPRISED IF WE SAW A FEW
LOCATIONS COME WITHIN A FEW DEGREES OF RECORD HIGHS.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 254 AM MDT SUN AUG 25 2013
MUCH OF THE SAME FOR THE SECOND HALF OF THIS WEEK WITH HOT AND DRY
CONDITIONS CONTINUING. A BROAD H5 RIDGE CENTERED OVER KANSAS WILL BE
WELL-ESTABLISHED BY MID-WEEK. THIS RIDGE WILL GRADUALLY BUILD WEST
OVER THE REST OF THE WEEK...KEEPING THE SENSIBLE WX FAIRLY BENIGN.
THE ONLY INTERESTING FEATURE IS A WEAK VORT MAX THAT MAY MOVE ACROSS
EASTERN COLORADO INTO WESTERN KANSAS LATE THURSDAY. WHILE THERE WILL
BE SOME UPPER-LEVEL MOISTURE...SOUNDINGS APPEAR TOO STABLE TO
SUPPORT WIDESPREAD STORMS. THE OPERATIONAL GFS PRINTS OUT SOME QPF
IN WESTERN KANSAS FROM THIS...AS WELL AS JUST ONE OF THE TWELVE
ENSEMBLE PERTURBATIONS...SO HAVE LITTLE CONFIDENCE IN ANY PRECIP
BEING REALIZED. RIDGE CONTINUES DRIFTING WESTWARD OVER THE
WEEKEND WHILE AN UPPER LOW MOVING INTO THE PACIFIC NORTHWEST MAY
HELP TO WEAKEN THE RIDGE LATE IN THE WEEKEND. FOR NOW...NO PRECIP
CHANCES THROUGH SATURDAY AFTERNOON. FOR TEMPS...ALL GUIDANCE
CONTINUES TO TREND WARMER FOR THE PERIOD WITH 850MB TEMPS IN THE LOW
30S C. TEMPS WILL BE NEARLY THE SAME EVERY DAY...HIGHS IN THE MID TO
UPPER 90S AND LOWS IN THE MID 60S TO LOW 70S. HIGHS ARE NOT EXPECTED
TO BE RECORD BREAKING...BUT A FEW STATIONS COULD APPROACH RECORD
HIGHS ANY DAY OF THE EXTENDED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1154 PM MDT SAT AUG 24 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT MCK AND GLD.
SOUTH WINDS WILL INCREASE AND BECOME GUSTY DURING THE DAY ON
SUNDAY BETWEEN 14Z AND 23Z AND WILL LOSE THE GUSTS FOLLOWING SUNSET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JJM
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GRAY ME
917 PM EDT MON AUG 26 2013
.SYNOPSIS...
LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL TRACK INTO SOUTHERN
NEW ENGLAND TONIGHT THEN EASTWARD OFF CAPE COD ON TUESDAY. THIS
WILL LEAVE NORTHERN NEW ENGLAND IN A WARM AND HUMID AIR MASS WITH
ISOLATED SHOWERS AND THUNDERSTORMS. A WEAK DISTURBANCE WILL CROSS
THE REGION WEDNESDAY AND THURSDAY FOLLOWED BY A WEAK RIDGE OF HIGH
PRESSURE FRIDAY. A COLD FRONT WILL DROP SOUTH INTO THE REGION
FRIDAY NIGHT AND SATURDAY BEFORE RETURNING NORTH AS A WARM FRONT
FOR SUNDAY. A COLD FRONT WILL CROSS THE AREA ON MONDAY. &&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT RADAR TRENDS. HAVE LOWERED
POPS OVER MAINE DURING THE LATE EVENING HOURS TO ESSENTIALLY
ZERO...WHILE INCREASING POPS ACROSS FAR SOUTHERN NH. LARGE AREA OF
CONVECTION WILL CONTINUE TO HEAD SOUTHEAST AS PER LATEST HRRR RUNS
SUGGEST. MOST OF THE REGION WILL REMAIN DRY HOWEVER FOR MUCH OF THE
NIGHT.
HAVE ALSO MADE ADJUSTMENTS TO TEMPERATURE...DEW POINT AND CLOUD
COVER FOR THE NEXT FEW HOURS. THE REST OF THE GRIDDED PACKAGE WILL
REMAIN UNCHANGED.
PREV DISC...
AFTER SOME BREAKS IN THE CLOUDS SOUTHWEST OF THE HIGHER
TERRAIN THIS AFTERNOON, CLOUDS ARE STARTING TO FILL BACK IN. SKIES
SHOULD BE PARTLY TO MOSTLY CLOUDY TONIGHT WITH DEW POINT
TEMPERATURES IN THE 60S, SO PATCHY FOG IS LIKELY. THE MESOSCALE
CONVECTIVE SYSTEM IN WESTERN NEW YORK IS LIKELY TO TRACK THROUGH
SOUTHWESTERN NEW ENGLAND THIS EVENING AND REMAIN SOUTH OF THE
FORECAST AREA. A FEW LIGHT SHOWERS ARE POSSIBLE NEAR THE
MASSACHUSETTS BORDER TOWARD DAYBREAK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AFTER SOME BREAKS IN THE CLOUDS SOUTHWEST OF THE HIGHER TERRAIN
THIS AFTERNOON, CLOUDS ARE STARTING TO FILL BACK IN. SKIES SHOULD
BE PARTLY TO MOSTLY CLOUDY TONIGHT WITH DEW POINT TEMPERATURES IN
THE 60S, SO PATCHY FOG IS LIKELY. THE MESOSCALE CONVECTIVE SYSTEM
IN WESTERN NEW YORK IS LIKELY TO TRACK THROUGH SOUTHWESTERN NEW
ENGLAND THIS EVENING AND REMAIN SOUTH OF THE FORECAST AREA. A FEW
LIGHT SHOWERS ARE POSSIBLE NEAR THE MASSACHUSETTS BORDER TOWARD DAYBREAK.
&&
.SHORT TERM /TUESDAY NIGHT/...
THE WARM AND HUMID AIR MASS REMAINS IN PLACE ON TUESDAY, WITH
AMPLE INSTABILITY FOR THUNDER IN THE AFTERNOON AND EVENING -- IF
WE CAN COUNT ON THE MOUNTAINS TRIGGERING CONVECTION AS THERE
REALLY IS NO DYNAMIC FORCING EXPECTED. HAVE KEPT POPS AS LOW
CHANCE TUESDAY AND TUESDAY NIGHT WITH ONLY LIGHT PRECIPITATION
AMOUNTS EXPECTED. LOW PRESSURE BEGINS TO DEVELOP NEAR SOUTHEASTERN
NEW ENGLAND TUESDAY EVENING BUT SHOULDN`T AFFECT COASTAL NH/ME
UNTIL WEDNESDAY AT THE EARLIEST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THE MODELS ARE IN DECENT AGREEMENT THROUGH FRIDAY BEFORE DIFFERENCES
BEGIN TO EMERGE. THE UPPER HIGH WILL WEAKEN A BIT AND SHIFT FURTHER
WEST AS SERIES OF IMPULSES RIDE OVER THE TOP OF THE RIDGE. BY THE
END OF THE PERIOD...WE TRANSITION TO A HIGHER AMPLITUDE PATTERN
WITH A RIDGE OVER THE WEST-CENTRAL U.S. AND AN EASTERN TROUGH. WE
BEGIN THE PERIOD WITH AN IMPULSE DIVING OVER THE TOP OF THE RIDGE
INTO NEW ENGLAND FOR WEDNESDAY WITH A LINGERING TROUGH AND UNSETTLED
WEATHER INTO THURSDAY. ON FRIDAY...ONLY A SLIGHT CHANCE OF SHOWERS
AS WEAK RIDGING OCCURS AHEAD OF THE NEXT IMPULSE AND AN ASSOCIATED
COLD FRONT THAT DROPS INTO THE REGION FRIDAY NIGHT/EARLY SATURDAY
BEFORE RETURNING NORTH AS A WARM FRONT BY SUNDAY. A COLD FRONT
WILL CROSS THE AREA ON MONDAY.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...MVFR CEILINGS THIS EVENING WILL GIVE WAY TO SCATTERED
IFR/LIFR IN VALLEY FOG. VFR TUESDAY AND TUESDAY NIGHT EXCEPT WHERE
FOG DEVELOPS.
LONG TERM...
WED - THU...SCT MVFR IN SHOWERS AND TSTMS.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT ADVISORY
CRITERIA THROUGH WEDNESDAY.
LONG TERM...
FRI NIGHT - SAT...WINDS AND SEAS MAY APPROACH SMALL CRAFT OUTSIDE
THE BAYS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
428 PM EDT SUN AUG 25 2013
.SYNOPSIS...
A WARM FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT AND WILL
GRADUALLY CROSS THE REGION ON MONDAY FOLLOWED BY A WEAK COLD FRONT
MONDAY NIGHT. WEAK HIGH PRESSURE WILL BUILD OVER THE AREA ON
TUESDAY. LOW PRESSURE WILL APPROACH FROM THE WEST TUESDAY NIGHT
AND WILL PASS SOUTH OF NEW ENGLAND ON WEDNESDAY. A TROUGH OF LOW
PRESSURE WILL LINGER OVER THE REGION ON THURSDAY AS LOW PRESSURE
SHIFTS EAST INTO THE MARITIMES. THE TROUGH WILL SLOWLY MOVE SOUTH
THROUGH THE REGION ON FRIDAY. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT DEW POINT AND TEMPERATURES
OBSERVATIONS. CLOUDS WILL ALSO BE ENTERING THE FORECAST AREA
SHORTLY FROM THE WEST...WITH THE LATEST HRRR RUN TIMING ANY SHOWER
ACTIVITY WILL OCCUR AFTER MIDNIGHT OVER WESTERN ZONES.
PREV DISC...
INCREASING CLOUDS TONIGHT AS A WARM FRONT APPROACHES FROM THE
WEST. CONVECTIVE COMPLEX MOVING THROUGH EASTERN ONTARIO WILL DIE
OUT OVER WESTERN NEW YORK LATER THIS AFTERNOON AND THIS EVENING
BUT A FEW SHOWERS WILL EVENTUALLY MAKE IT INTO THE FORECAST AREA
GENERALLY AFTER MIDNIGHT. SHOULD SEE A MUCH WARMER NIGHT WITH LOWS
RANGING THROUGH THE 50S FROM NORTH TO SOUTH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
ANY LINGERING SHOWERS WILL PUSH SOUTH OF THE REGION MONDAY MORNING
AND MUCH OF THE DAY NOW LOOKS DRY WITH VARIABLE MID LEVEL CLOUDS.
MAY BE ENOUGH INSTABILITY IN SOUTHERN NEW HAMPSHIRE TO POP OFF AN
AFTERNOON SHOWER OR THUNDERSTORM BUT APPEARS BEST CAPES REMAIN
SOUTH AND WEST OF THE FORECAST AREA. EXPECT HIGH FROM THE MID 70S
TO NEAR 80.
WEAK COLD FRONT WILL DROP SOUTH THROUGH THE REGION MONDAY NIGHT.
MAY BE ENOUGH TO POP OFF AN ISOLATED SHOWER OR THUNDERSTORM BUT NOT
LOOKING FOR ANY WIDESPREAD ACTIVITY. WILL BE ANOTHER MILD NIGHT
WITH LOWS IN THE MID 50S TO LOWER 60S.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THE UPPER LEVEL TROF AND WEAK LOW/SFC WARM FRONT MOVE TO OUR E AND
SE BY 12Z TUESDAY ALLOWING WEAK HIGH PRESSURE UNDER AN UPPER LEVEL
RIDGE TO BUILD INTO THE REGION GIVING US FAIR AND VERY WARM WX FOR
TUESDAY INTO EARLY TUESDAY NIGHT. A BROAD LARGE SCALE UPPER LEVEL
RIDGE BUILDS OVER THE CENTRAL AND WRN U.S. ALLOWING A LONG WAVE TROF
TO CARVE OUT OVER THE ERN U.S. AS A SERIES OF WEAK UPPER LEVEL TROFS
MOVE INTO THE ERN U.S.
THIS WILL PROVIDE UNSETTLED WX FROM LATE TUESDAY NIGHT THRU
WEDNESDAY EVENING UNTIL A MORE ORGANIZED UPPER LEVEL TROF FORMS AND
FORCES LOW PRESSURE TO GAIN SOME STRENGTH WHILE MOVING FROM S OF THE
GULF OF MAINE OFF TO THE NE ON THURSDAY. DEPENDING ON HOW CLOSE THE
SFC LOW TRACKS WILL DETERMINE IF WE RECEIVE MORE ORGANIZED RAIN LATE
WEDNESDAY NIGHT THROUGH THURSDAY MORNING AND POSSIBLY INTO THE
AFTERNOON.
THE AXIS OF THE UPPER LEVEL TROF SHIFTS SLOWLY EAST BUT MAINTAINS A
CYCLONIC FLOW ALOFT THURSDAY NIGHT AND FRIDAY SO THAT SOME
INSTABILITY SHRA ARE POSSIBLE. GRADUALLY AN UPPER LEVEL RIDGE BUILDS
IN FRIDAY NIGHT AND SATURDAY ALLOWING HIGH PRESSURE TO APPROACH FROM
CANADA. THIS BRINGS DRIER AND COOLER WX FRIDAY NIGHT AND SATURDAY.
THE UPPER LEVEL RIDGE BREAKS DOWN AS A SHORT WAVE DRIVES EASTWARD
THRU THE RIDGE BRINGING WARMER AND MORE HUMID AIR /THUS INCREASING
INSTABILITY/ INTO THE REGION ALONG WITH ISOLD TO MAYBE SCT SHRA AND
TSTMS ON SUNDAY...EVEN THOUGH THE TROF IS WEAKENED AS IT MOVES THRU
THE UPPER LEVEL RIDGE AND THE ASSOCIATED WEAK SFC FRONT STAYS WELL
TO OUR NW.
GENERALLY USED BLEND OF GFS/NAM/MET/MAV/HPC QPF FOR PERIODS 4 AND 5
THEN A BLEND OF GFS40/GMOS/MEX FOR THE REST OF THE LONG TERM FCST.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
SHORT TERM...VFR TONIGHT THROUGH MONDAY. AREAS OF MVFR/IFR
CEILINGS MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH FRIDAY/...UNSETTLE WX LATE TUESDAY
NIGHT THRU THURSDAY AND POSSIBLY INTO FRIDAY WITH THE POTENTIAL
FOR MVFR/IFR CONDITIONS AT TIMES.
&&
.MARINE...
SHORT TERM...NO FLAGS.
LONG TERM /TUESDAY THROUGH FRIDAY/...WINDS AND SEAS EXPECTED TO
BE BELOW SCA CRITERIA DUE TO WEAK PRESSURE GRADIENT. HOWEVER...
PASSING LOW OUTSIDE OF THE COASTAL WATERS MAY STRENGTHEN ON
THURSDAY AND THURSDAY NIGHT THAT COULD PRODUCE CONDITIONS
APPROACHING SCA LEVELS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
715 PM EDT MON AUG 26 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 418 PM EDT MON AUG 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE
CENTERED OVER MO/KS RESULTING IN ACYC FLOW FROM THE NRN PLAINS
THROUGH THE UPPER MS VALLEY INTO THE GREAT LAKES. WAA IN ADVANCE OF
AN UPSTREAM SHORTWAVE TROUGH MOVING INTO SW NORTH DAKOTA SUPPORTED
AN AREA OF LIGHT TO MODERATE RAIN WITH ONLY ISOLD TSRA. AT THE
SFC...THE CONVECTION THIS MORNING HELPED PUSH THE WEAK FRONTAL
BOUNDARY INTO NRN WI AND EXTENDED FROM NEAR HYR TO GRB. TEMPS TO THE
SOUTH OF THE FRONT HAVE AGAIN CLIMBED TO AROUND 90 WHILE MORE
MODERATE READINGS IN THE LOW TO MID 80S PREVAILED TO THE NORTH.
DEWPOINTS THROUGH THE REGION WERE NEAR 70F WITH 12Z OBSERVED AND
FCST SOUNDINGS SHOWING PWAT VALUES AROUND 2.0 INCHES(200 PCT OF
NORMAL).
EXPECT THAT AS THE ND SHRTWV MOVES TO THE EAST AND WAA INCREASES
THIS EVENING...EXPECT SHRA/TSRA TO DEVELOP AND QUICKLY IN INCREASE
IN COVERAGE BY LATE EVENING IN THE VCNTY OF THE SFC-800 MB FRONT
FROM CNTRL MN INTO NW WI. EVEN THOUGH THE MODELS HAVE TRENDED
FARTHER SOUTH WITH THE PCPN AND SHOW THE MOST FAVORABLE 310K
ISENTROPIC LIFT REMAINING SOUTH OF THE CWA...THERE IS STILL
CONSIDERABLE UNCERTAINTY ON THE LOCATION OF THE STRONGEST CONVECTION.
MOST OF THE HIGHER RES MODELS KEEP NEARLY ALL THE PCPN SOUTH OF
THE CWA WHILE THE GFS/ECMWF AND HIGH RES RAPID REFRESH BRING PCPN
THROUGH MAINLY THE SW HALF OF THE CWA. SO...THE HIGHER POPS/QPF WERE
SHIFTED TO THE SOUTH WITH LOCATIONS ALONG THE WI BORDER SEEING THE
GREATEST POTENTIAL FOR STRONG TSRA.
WITH MUCAPE VALUES INTO THE 1000-1500 J/KG RANGE AND EFFECTIVE SHEAR
TO AROUND 30 KT...THERE IS THE POTENTIAL FOR MULTICELL CLUSTERS THAT
COULD PRODUCE VERY HEAVY RAIN AND LCL WIND DAMAGE...SIMILAR TO LAST
NIGHT. FCST CORFIDI VECTORS SUGGEST THAT STORM ELEMENTS SHOULD KEEP
ENOUGH FORWARD MOTION TO LIMIT POTENTIAL FOR EXCESSIVE RAINFALL.
HOWEVER...ONE TO TWO INCHES AMOUNTS MAY AGAIN BE COMMON ALONG THE
PATH OF HEAVIER CLUSTERS. ANY LEFTOVER SHRA/TSRA TUE MORNING OVER
MAINLY THE S CNTRL CWA IS EXPECTED TO DIMINISH AND SAG OFF TO THE SE
BY EARLY TO MID AFTERNOON.
WITH 850 MB TEMPS REMAINING AROUND 18C...MAX TEMPS SHOULD ALSO BE
SIMILAR TO TODAY WITH HIGHS INTO THE LOW TO MID 80S WITH SLIGHTLY
COOLER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 439 PM EDT MON AUG 26 2013
NO SIGNIFICANT RELIEF FROM THE WARM WEATHER. AVERAGE HIGH
TEMPERATURES THIS TIME OF YEAR ARE IN THE MID 70S FOR MUCH OF UPPER
MICHIGAN. TEMPERATURES SHOULD REMAIN 5-10F ABOVE NORMAL THROUGH THE
WEEKEND. WE CAN BASICALLY EXPECT QUIET WEATHER UNTIL THURSDAY
NIGHT...AS THE DOMINANT 500MB HIGH REMAINS OVER MUCH OF THE CENTRAL
AND SOUTHERN U.S. THE NEXT SHORTWAVE TO ROUND THE RIDGE IS CURRENTLY
MOVING IN OVER THE SW STATES...ALONG THE BAJA AND S CA SHORE THIS
AFTERNOON...HELPING PRODUCE A STRING OF SHOWERS AND A FEW
THUNDERSTORMS.
THE SHORTWAVE WILL TOP THE RIDGE ACROSS ND WEDNESDAY
AFTERNOON/EVENING...BEFORE PUSHING INTO N MN WEDNESDAY NIGHT/EARLY
THURSDAY. KEPT THE MENTION OF CHANCE RA AND SLIGHT CHANCE TS IN THE
FCST FOR THE FAR W THURSDAY AFTERNOON...SLIDING OVERHEAD THURSDAY
NIGHT...AND ENDING FRIDAY.
ANOTHER GOOD CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
SATURDAY AFTERNOON/EVENING THROUGH THE REST OF THE WEEKEND...IN
ADVANCE OF A DEEPENING SFC LOW ACROSS S CENTRAL CANADA. EXPECT THE
LOW TO SLIDE INTO ONTARIO SATURDAY NIGHT...AND EXIT INTO QUEBEC
SUNDAY AFTERNOON /AS SHOWN ON THE 26/12 ECMWF/. THE GFS IS ROUGHLY
12HRS SLOWER. BEHIND THE COLD FRONT THERE WILL LIKELY BE A
COOL-DOWN. IF NOTHING ELSE A TEMPORARY RETURN TO NEAR NORMAL
TEMPERATURES LOOK LIKELY MONDAY AFTERNOON. THE OPERATIONAL ECMWF
CAME IN WITH UPPER 50S TO MID 60S ON COOL NW FLOW. WHILE 50S DO NOT
LOOK ALL THAT LIKELY MID 60S WILL BE POSSIBLE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 715 PM EDT MON AUG 26 2013
EXPECT MOSTLY DRY/VFR CONDITIONS INTO THIS EVENING THEN LATER
TONIGHT MORE SHRA/TSRA COULD IMPACT THE REGION YET AGAIN.
HOWEVER...THE BEST CHANCE OF SHRA/TSRA IS EXPECTED TO REMAIN
FARTHER TO THE SOUTH AND WEST...WITH IWD SEEING THE GREATEST
SHRA/TSRA POTENTIAL AND MVFR CONDITIONS POSSIBLE. VCTS INCLUDED AT
IWD AS A START TO HINT AT THE EXPECTED TIMING OF THE SHRA/TSRA.
COULD END UP WITH SOME GROUNDFOG AT SAW DUE TO RAIN FROM YESTERDAY
AND LIGHT WINDS AND PUT IN MVFR VIS FOR THIS. VFR CONDITIONS
EXPECTED FOR ALL TAF SITES ON TUE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 418 PM EDT MON AUG 26 2013
WINDS LESS THAN 20 KTS EXPECTED ACROSS LK SUPERIOR MUCH OF THIS
WEEK. THE ONLY EXCEPTION WOULD BE WHEN STRONGER THUNDERSTORMS ROLL
ACROSS THE WRN LAKE AND PRODUCE STRONGER GUSTS...AS HAS BEEN SEEN
THE LAST SEVERAL DAYS. OTHER THAN THOSE THUNDERSTORMS...GIVEN THE
WARM AND HUMID AIRMASS IN PLACE ALONG WITH ADDITIONAL MOISTURE FROM
SHOWERS AND THUNDERSTORMS...AREAS OF DENSE FOG WILL BE THE OTHER
MAIN CONCERN THROUGH MUCH OF THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
351 PM EDT SUN AUG 25 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 350 PM EDT SUN AUG 25 2013
A WARM FRONT WILL MOVE EAST OF THE AREA THIS EVENING PUTTING
SOUTHWEST MICHIGAN IN WARM AND HUMID AIR UNTIL THE COLD FRONT
COMES THROUGH WEDNESDAY MORNING. EXPECT PERIODS OF THUNDERSTORMS
FROM MONDAY AFTERNOON INTO WEDNESDAY MORNING. FOR MOST OF THE AREA
THE GREATEST RISK OF SIGNIFICANT RAINFALL IS TUESDAY INTO TUESDAY
NIGHT. WARM DRY WEATHER WILL THEN PREVAIL UNTIL THE NEXT WARM
FRONT COMES THROUGH NEXT WEEKEND. THAT COULD BE THE HOTTEST
WEATHER OF THE SUMMER.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 350 PM EDT SUN AUG 25 2013
WE ARE WATCHING TWO SIGNIFICANT FEATURES THIS AFTERNOON... FIRST IS
THE POTENTIAL FOR THUNDERSTORMS ONCE WE ARE SOLIDLY IN THE WARM
AND HUMID AIR... THEN THE SECOND ISSUE IS JUST HOW HOT IT GET THE
NEXT TWO AFTERNOONS.
FIRST THE CONVECTION ISSUE. IT NOW SEEMS THE FRONTAL BOUNDARY OVER
THE UPPER PENINSULA WILL NOT MAKE MUCH PROGRESS SOUTH TONIGHT SO I
DO NOT EXPECT THE CONVECTION ASSOCIATED WITH IT TO MAKE MUCH
PROGRESS EITHER. THIS IS SHOWN BY THE NSSL AND SPC WAF... AND THE
HRRR MODELS AS WELL AS THE RAP MODEL. WELL THE CONVECTION WILL
MOVE SOUTH FROM WHERE IT IS BUT IT SHOULD NOT GET MUCH FATHER
SOUTH THEN ROUTE 10 BY MORNING SO I HAVE LOW CHANCE POPS UP THERE.
THAT IS BASED ON THE LOW LEVEL JET AXIS NOT GETTING MUCH FARTHER
SOUTH THAN CAD/HTL BY 12Z. NOTE THAT THERE ARE TWO PRIMARY
SHORTWAVES DRIVING ALL OF THIS. THIS FIRST ONE IS MOVING EAST WITH
THE CONVECTION NORTHEAST OF LAKE HURON. THE SECOND IS LESS
OBVIOUS BUT IS CURRENTLY OVER THE DAKOTAS AND HEADING EAST OVER
THE TOP OF THE UPPER RIDGE. IT IS THAT SHORTWAVE THAT WILL SPARK
THE CONVECTION OVER NRN WI AND THE UPPER PENINSULA THIS EVENING
INTO THE OVERNIGHT HOURS. THAT CONVECTION WILL DRIVE THE COLD
FRONT SOUTH TONIGHT AND MAY BRING THUNDERSTORMS TO OUR NORTHERN
CWA BY SUNRISE.
THIS LEAD SHORTWAVE CREATES A SORT OF COLD FRONT /WARM FRONT SET
UP. SO THE COLD FRONT TRAILING THE LEAD SHORTWAVE IS WHAT DIVES
THE CONVECTION SOUTH TONIGHT INTO MONDAY. THEN THE NEXT UPSTREAM
WAVE PUSHES IT ALL BACK NORTH AS A WARM FRONT MONDAY NIGHT. THERE
IS AN UPPER LEVEL JET ASSOCIATED WITH THIS SO I WOULD EXPECT
ANOTHER ROUND OF CONVECTION MONDAY NIGHT INTO TUESDAY MORNING WITH
THAT. HOWEVER... IF THE COLD FRONT DOES NOT GET TOO FAR SOUTH
MONDAY... THEN MOST OF THE STORMS SHOULD WELL NORTH OF INTERSTATE
96 MONDAY NIGHT.
FINALLY THE SHORTWAVE OVER NV CURRENTLY CLIMBS THE UPPER RIDGE AND
DIVES DOWN THE FRONT SIDE OF IT TUESDAY AND THAT BRINGS A MORE
SIGNIFICANT COLD FRONT THROUGH THE AREA BY EARLY WEDNESDAY. IT IS
THAT NV SHORTWAVE THAT I BELIEVE WILL BRING OUR BEST SHOT FOR SIGNIFICANT
RAINFALL. THIS WILL LIKELY BE IN THE TUESDAY AFTERNOON INTO
TUESDAY NIGHT TIME FRAME. IT WOULD BE THEN THAT THERE WOULD BE THE
GREATEST RISK OF STRONG TO SEVERE STORMS. DEEP LAYER SHEAR IS IN
THE 30 TO 40 KNOT RANGE DURING THAT TIME AND MIX LAYER CAPES
AROUND 1500 J/KG. WITH PRECIPITABLE WATER VALUES NEAR 2 INCHES
THERE IS LITTLE QUESTION IF WE GET THUNDERSTORMS MINOR FLOODING OF
AREAS WITH POOR DRAINAGE IS A REAL THREAT.
AS FOR HOW HOT IT WILL GET... THE 850 TEMPS ARE AROUND 21C MONDAY
AND TUESDAY. THAT WOULD SUPPORT HIGHS IN LOWER 90S FOR SURE. ALSO THE
1000/925 MB THICKNESS VALUES SUGGEST MID 90S ACTUALLY. THE ONLY
THING THAT WILL KEEP OUR TEMPERATURES FROM GETTING THAT WARM IS IF
THERE IS TO MUCH CONVECTIVE DEBRIS CLOUDS AROUND. WHICH IS A REAL
PROBLEM FOR THIS FORECAST AS THE COLD FRONT WILL COME CLOSE TO US
MONDAY AFTERNOON AND EARLY EVENING. MOS TEMP FORECASTS KEEP HIGHS IN
THE 80S BOTH DAY BUT GIVEN HOW WARM THE THICKNESS IS AND 850 TEMPS
I HAVE A REAL PROBLEM FORECASTING HIGHS SO LOW. SO WE HAVE TO WAIT
AND SEE JUST HOW MUCH CLOUDS GET GENERATED FROM THE UPSTREAM
CONVECTION TO SEE HOW HOT IT REALLY GETS THE NEXT TWO DAYS.
MEANWHILE I WILL GO WITH HIGHS IN THE LOWER 90S FOR NOW AND CALL
THAT GOOD.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 350 PM EDT SUN AUG 25 2013
THE GOING MID SUMMER-LIKE FORECAST AND MAINLY DRY CONDITIONS IN THE
LONG TERM CONTINUES TO LOOK ON TRACK.
WE CONTINUE TO EXPECT THAT THE FRONT SHOULD BE EXITING THE FCST AREA
TO THE SOUTH RIGHT AROUND 12Z WED. THIS OCCURS AS THE UPPER HEIGHTS
LOWER SLIGHTLY OVER THE AREA...AND NW FLOW ALOFT COMMENCES. THIS
WILL RESULT IN DRY CONDITIONS...TEMPS DROPPING A COUPLE OF DEGREES
AND SLIGHTLY LOWER HUMIDITY LEVELS AS WE COULD POTENTIALLY SEE ON
TUE. H850 TEMPS DROP TO AROUND 18-19C WHICH WOULD STILL SUPPORT
HIGHS IN THE MID 80S TO AROUND 90.
THE MODELS CONTINUE TO INDICATE SOME SORT OF MCS DEVELOPING TO OUR W
LATE THU AND MOVING SE ALONG THE UPPER RIDGE ON FRI. WE HAVE BETTER
CONFIDENCE AT THIS TIME THAT THIS COMPLEX WILL END UP SW OF THE AREA
CLOSER TO THE BETTER INSTABILITY SOUTH OF THE FRONT. VERY WARM AND
DRY CONDITIONS ARE EXPECTED ONCE AGAIN FOR FRI.
WE EXPECT TO SEE ANOTHER SURGE OF HEAT THEN BEGINNING NEXT WEEKEND.
WE WILL SEE THE UPPER RIDGE AXIS BUILD BACK OVER THE AREA BY NEXT
SUN AS SHORT WAVE ENERGY MOVING ACROSS CANADA WILL SHIFT IT E/SE.
INCREASING LOW LEVEL SW FLOW AHEAD OF THE SFC LOW WILL HELP TO
ADVECT THE HOT TEMPS OVER THE PLAINS OVER OUR AREA. H850 TEMPS ARE
FCST TO INCREASE TO THE LOWER 20S C BY NEXT SUN. WE COULD SEE MAX
TEMPS WELL INTO THE 90S IF THIS PLAYS OUT THIS WAY. WE HAVE GONE
SOMEWHAT CONSERVATIVE FOR NOW WITH HIGHS IN THE LOWER TO MID 90S.
THE TRANSITION OF THIS AIR MASS INTO THE AREA COULD BRING A LOW CHC
OF PCPN TO THE AREA ON SUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 126 PM EDT SUN AUG 25 2013
MAIN ITEMS OF CONCERN IN THE 18Z FCST CYCLE ARE CONVECTIVE CHCS LATE
IN THE PERIOD AND WIND GUST TRENDS.
THE ONLY CONCERN IN THE FIRST FEW HOURS OF THE 18Z FCSTS WILL BE
WIND GUSTS. STRONGER GRADIENT MOVING IN IS HELPING TO PRODUCE WIND
GUSTS AS HIGH AS 25 KNOTS THIS AFTERNOON. SOME HIGHER WINDS ARE IN
PLACE A COUPLE OF THOUSAND FEET UP DUE TO THE WARMER AIR ADVECTING
IN. WE EXPECT THE WIND GUSTS TO DIMINISH AROUND SUNSET TONIGHT OR
00-01Z. VFR CONDITIONS WILL RULE THROUGH THEN WITH ONLY A COUPLE
OF PATCHES OF 6K FT CLOUDS AND SOME THIN HIGH CLOUDS OVERHEAD.
THE VFR CONDITIONS WILL CONTINUE OVERNIGHT. WE ARE MONITORING THE
TRENDS FOR A FEW SHOWERS AND/OR STORMS TO SINK SOUTH INTO THE I-96
TERMINALS EXTREMELY LATE TONIGHT AND ON MON. A FAIR AMOUNT OF UNCERTAINTY
REGARDING THIS POTENTIAL PCPN EXISTS AS IT SHOULD BE WANING AS IT
APPROACHES. WE BELIEVE IT IS TOO LOW AT THIS POINT IN TIME TO HAVE
IN THE FCST PRIOR TO 18Z. WIND GUSTS WILL COME UP ON MON AND
CLOUDS WILL BECOME A LITTLE MORE WIDESPREAD. VFR CONDITIONS SHOULD
CONTINUE TO RULE UNLESS THE PCPN MAKES IT IN EARLIER.
&&
.MARINE...
ISSUED AT 350 PM EDT SUN AUG 25 2013
WITH THE WINDS IN THE BOUNDARY LAYER FORECAST TO BE 20 - 35 KNOTS
INTO MONDAY EVENING IT SEEMS MORE THAN REASONABLE TO KEEP THE
BEACH HAZARD STATEMENT GOING AND THE SMALL CRAFT ADVISORY.
&&
.HYDROLOGY...
ISSUED AT 350 PM EDT SUN AUG 25 2013
WHILE LARGE AREA HEAVY RAINFALL IS NOT EXPECTED... THERE IS LITTLE
QUESTION WITH ALL THE PRECIPITABLE WATER OVERHEAD THE NEXT 2-3
DAYS... IF WE DO SEE ANY THUNDERSTORMS SOME VERY HEAVY RAINFALL
SHOULD BE EXPECTED AS WELL AS LOCALIZED FLOODING IF THE STORMS
MOVE OVER AN URBAN AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH LATE MONDAY NIGHT FOR MIZ037-043-
050-056.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR LMZ846>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
401 PM CDT SUN AUG 25 2013
.SYNOPSIS...
ISSUED AT 359 PM CDT SUN AUG 25 2013
NOT MUCH HAS CHANGED IN THE UPPER LEVELS IN THE LAST 24 HRS...WITH A
598 DM HIGH CENTERED OVER MISSOURI THAT IS STILL FLANKED BY TROUGHS
ON EITHER COAST OF NOAM. ACROSS THE ROCKIES...WATER VAPOR IMAGERY IS
SHOWING A TROPICAL MOISTURE PLUME FROM THE REMNANTS OF AN ERN
PACIFIC TROPICAL SYSTEM CURRENTLY OVER THE BAJA PENINSULA THAT IS
NOW WORKING ITS WAY AROUND THE WRN PERIPHERY OF THE MISSOURI HIGHS
AND ALREADY MOVING UP INTO WYOMING...LIKELY REACHING THE UPPER MS
VALLEY MONDAY.
AT THE SFC A TROUGH OF LOW PRESSURE WAS SITUATED FROM CENTRAL SODAK
NE TO NEAR INL. STRONG PRESSURE GRADIENT IS STILL IN PLACE...WITH
BREEZY SOUTHWEST WINDS CONTINUING. WITH TEMPS IN THE LOW TO MID 90S
AND DEWPS IN THE LOW TO MID 70S...STARTING TO SEE HEAT INDICES CLIMB
TO OVER 100 DEGREES...WITH VALUES OF MLCAPE UP SAFELY IN THE HEALTHY
RANGE BETWEEN 3500 AND 6000 J/KG.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 359 PM CDT SUN AUG 25 2013
AS CAN BE IMAGINED...WITH A CAPPED...WEAKLY FORCED...HIGH CAPE
ENVIRONMENT...CONFIDENCE IS STILL QUITE LOW ON WHERE/IF CONVECTION
WILL FIRE LATER THIS EVENING. ONE THING IS FOR SURE...PRESENCE OF
ENOUGH INSTABILITY IS NOT AN ISSUE!
WHEN LOOKING AT THE SPC MESO ANALYSIS AND SATELLITE ALONG
WITH A FEW INSTABILITY/MOISTURE TRANSPORT FIELDS FROM THE
DETERMINISTIC MODELS YOU CAN GET A SENSE OF HOW THINGS SHOULD TRY TO
UNFOLD THIS EVENING. FROM THE MESO ANALYSIS SIDE OF THINGS...THERE
IS A GRADIENT IN THE MLCAPE FIELD ACROSS CENTRAL MN...WHICH IS
COINCIDENT WITH THE NRN EDGE OF THE STEEPER MID LEVEL LAPSE RATES
ASSOCIATED WITH AN EML AND STRONGER CAPPING. JUST NORTH OF THE
MLCAPE GRADIENT...THE 20Z ANALYSIS SHOWS H7 DEWPOINTS BETTER THAN
10C ACROSS THE SRN END OF THE DLH/FGF FORECAST AREAS. WITHIN THIS
ZONE OF HIGHER MOISTURE AT H7 MOISTURE...A SHALLOW CU FIELD HAS
DEVELOPED BENEATH A FEW BITS OF ACCUS THAT STRETCH FROM AROUND
FERGUS FALLS OVER TOWARD DULUTH. BEST GUESS RIGHT NOW IS THAT IF
STORMS ARE TO DEVELOP...IT WILL BE WITHIN THIS ZONE...LIKELY CLOSER
TO 00Z.
IN ADDITION...MODELS SHOW THE LLJ AND ASSOCIATED MOISTURE ADVECTION
VEERING SOME AND SAGGING SOUTH THROUGH THE NIGHT. THE AREA OF CLOUDS
REFERENCED ABOVE ALSO SITS ON THE NRN EDGE OF THE MAIN MOISTURE
TRANSPORT PLUME AT H85...WHICH MOST GUIDANCE SHOW COMING DOWN TO
ABOUT I-94 OVERNIGHT. IF SOMETHING CAN GET GOING...THE PRESENCE OF
THE LLJ SHOULD KEEP THE ACTIVITY GOING THROUGH MUCH OF THE NIGHT.
WITH THE RAP AND MOST OTHER MODELS SHOWING THE STRONGEST MOISTURE
TRANSPORT IN THE H85-H7 LAYER RESIDING OVER ERN MN/WRN
WI...CONTINUED TO ADVERTISE LIKELY POPS IN ERN AREAS...THAT TAIL OFF
TO LOW CHANCE POPS IN THE WEST FOR TONIGHT.
FROM THE SEVERE END OF THINGS...AN ENVIRONMENT ASSOCIATED WITH HIGH
MOISTURE CONTENT /PWATS CURRENT NEAR 2 INCHES/...DEEP MELTING
LAYERS...AND WEAK SHEAR MEANS LARGE HAIL WILL BE TOUGH TO COME BY.
HOWEVER...VALUES OF DCAPE UP AROUND 1500 J/KG INDICATES THE WIND
POTENTIAL IS CERTAINLY STILL THERE IF WE CAN GET ANY DEEP MOIST
CONVECTION GOING.
WHAT HAPPENS TONIGHT WILL GO A LONG WAY IN DETERMINING WHERE ANY
POTENTIAL CONVECTION CAN FIRE UP MONDAY AFTERNOON. THE QUESTION FOR
TOMORROW IS FAR SOUTH CAN THE BOUNDARY SLOWLY HEADING FOR CENTRAL MN
MAKE IT TONIGHT. IF WE DO SEE A GOOD AMOUNT OF CONVECTION
OVERNIGHT...THEN THERE IS A GOOD CHANCE THAT THE BOUNDARY CAN MAKE
IT DOWN TO ABOUT I-94. IF WE DO NOT SEE MUCH CONVECTION
TONIGHT...THEN IN ALL LIKELIHOOD...THE BOUNDARY WILL REMAIN NORTH OF
THE MPX AREA...WITH ANOTHER DAY OF CAPED SUNNY SKIES ENSUING. THE
NAM/SREF WOULD SUPPORT THE SRN IDEA...WHILE THE GFS/ECMWF/GEM GO
NORTH. FOR NOW WENT WITH CHANCE POPS AFTER 21Z FOR AREAS NORTH OF
I-94. FROM THE SEVERE PERSPECTIVE...ABOUT THE ONLY THING DIFFERENT
ABOUT MONDAY COMPARED TO TODAY IS THAT THE BELT OF STRONGER
WESTERLIES WILL HAVE SAGGED SOUTH A BIT MORE...INCREASING THE AMOUNT
OF DEEP LAYER SHEAR...WHICH WILL MAKE THE RISK OF LARGE HAIL A BIT
HIGHER OWING TO THE CHANCE OF GETTING AT LEAST WEAK SUPERCELL
STRUCTURES GOING.
LAST STOP IS WITH TEMPERATURES. OVERNIGHT...EXPECT CENTRAL MN TO
COOL A FEW DEGREES MORE THAN THEY DID LAST NIGHT AS THE PRESSURE
GRADIENT WEAKENS...ALLOWING FOR SOME RADIATIONAL COOLING TONIGHT.
STILL...WITH DEWPS AROUND 70...MOST PLACES SHOULD STILL STAY ABOVE
THAT MARK. FOR THE TWIN CITIES AND PLACES FARTHER SOUTH/EAST...WINDS
WILL REMAIN IN PLACE /THOUGH NOT AS STRONG AS LAST NIGHT/...WHICH
WILL KEEP SOME FORM OF MIXING GOING AND ONCE AGAIN MAKE IT A
STRUGGLE FOR A LOT OF PLACES TO DROP BELOW 80 WITHOUT THE HELP OF
RAIN.
FOR HIGHS TOMORROW...925-850 MB TEMPS ACTUALLY INCREASE A DEGREE OR
TWO AS COMPARED TO TODAY...WHICH WOULD THEORETICALLY MEAN WE COULD
GET A DEGREE OR TWO WARMER. HOWEVER...THERE IS THE POTENTIAL FOR A
BIG BUST WITH HIGHS TOMORROW DEPENDING ON WHAT HAPPENS WITH STORMS
TONIGHT. IF WE DO END UP SEEING FAIRLY WIDESPREAD AND ROBUST
CONVECTION OVERNIGHT...THIS WOULD LIKELY LEAVE BEHIND PLENTY OF
DEBRIS COLD COVER...PUTTING A DAMPER ON TEMPERATURES. THE HIRES NMM
EAST DOES EXACTLY THAT WITH CONVECTION OVERNIGHT. THE RESULTING
CLOUD COVER IT GENERATED FOR THE NEXT DAY RESULTED IN IT ONLY
GENERATING HIGHS IN THE MID/UPPER 80S. AT THE OTHER END OF THE
SCALE...A NIGHT OF LITTLE CONVECTION WILL RESULT IN ANOTHER DAY OF
LOTS OF SUN. IN THAT CASE...THEN HIGHS TOMORROW WOULD BE A DEGREE OR
TWO WARMER THAN TODAY...WITH HIGHS IN THE MID/UPPER 90S AND A FEW
100 DEGREE READINGS NOT OUT OF THE QUESTION IN WRN MN. AT ANY
RATE...DID NOT SEE ANYTHING GLARING CHANGE WITH THE TEMP FORECAST
TODAY THAT REQUIRED ANY CHANGES IN THE GOING HEAT HEADLINES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 359 PM CDT SUN AUG 25 2013
LONG TERM TRENDS CONTINUE TO SHOW HOT AND HUMID CONDITIONS WILL
CONTINUE THROUGH AT LEAST TUESDAY. LOCATION OF FRONTAL BOUNDARY
MONDAY NIGHT WILL DETERMINE TO WHAT EXTENT/LOCATION CONVECTIVE ACTIVITY
WILL DEVELOP OVER THE CWA. VARIOUS DETERMINISTIC MODELS SHOW THIS
BOUNDARY LIFTING SLOWLY BACK NORTH MONDAY NIGHT AND INTO TUESDAY
AS WEAK COOL FRONT/SURFACE LOW MOVES THROUGH THE AREA. WILL
CONTINUE THE CHANCE POPS OVER THE NORTHEAST THIRD OF THE AREA FOR
TUESDAY...WHICH SHOULD EXIT THE CWA BY TUESDAY EVENING. EXPECT
TEMPERATURES TO RANGE IN THE MID/SOME UPPER 90S AND DEWPOINTS
POOLING AHEAD OF BOUNDARY INTO THE LOWER 70S. HEAT INDEX VALUES
WILL RANGE 100F TO 105F WITH THE CURRENT HEAT ADVISORY/WARNING
STILL LOOKING GOOD CONTINUING THROUGH TUESDAY.
SOME COOLING BEHIND THE FRONT LINGERING INTO FRIDAY...MAINLY OVER
THE EASTERN PORTION OF THE CWA. RIDGING ALOFT DEVELOPS THEREAFTER
WITH SURFACE FRONT MEANDERING OVER CENTRAL MINNESOTA AGAIN INTO
THE WEEKEND. THE 12Z ECMWF IS SLOWER BUILDING THE UPPER RIDGE TO
THE EAST...WITH THE MAIN SURGE COMING NEXT SUNDAY. THE GFS BUILDS
IN NORTH BY SATURDAY. WILL GO ALONG WITH PRESENT TREND OF BRINGING
THE 90S BACK INTO THE AREA FOR SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1249 PM CDT SUN AUG 25 2013
BIGGEST SOURCE OF UNCERTAINTY REMAINS WITH IF/WHERE CONVECTION
WILL BE THIS EVENING/OVERNIGHT. LOOKING AT WHERE THE WEAK SFC
TROUGH MENTIONED IN THE UPDATE IS EXPECTED TO BE...ALONG WITH
FORECAST LLJ PLACEMENT...PROBABILITY FOR SEEING CONVECTION TONIGHT
WILL BE BEST ALONG/NORTH OF 94. CONFIDENCE IN STORMS TONIGHT STILL
LOW ENOUGH THAT HELD ANY TS MENTION TO A VC OR PROB30. WITH THAT
TROUGH SETTLING INTO CENTRAL MN OVERNIGHT...WINDS THERE WILL CALM
DOWN CONSIDERABLY...AND WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S
HZ/BR WILL LIKELY BECOME AN ISSUE TOWARD SUNRISE THERE.
KMSP...12Z TAF STILL LOOKED GOOD FOR TIMING OF ANY CONVECTION THIS
EVENING. CONFIDENCE HAS NOT INCREASED ENOUGH TO GO WITH ANYTHING
MORE THAN THE PROB30 AT THIS POINT. IF WE DO NOT SEE ANY
CONVECTION OVERNIGHT...THEN THE HIGH MOISTURE CONTENT AT LOWER
LEVELS WILL LIKELY LEAD TO SOME MINOR ISSUES WITH HAZE MONDAY
MORNING. ANY CONVECTION POSSIBILITIES MONDAY AFTERNOON WILL DEPEND
HEAVILY ON HOW FAR SOUTH ANY CONVECTION TONIGHT CAN PUSH THE
BOUNDARY HEADING FOR CENTRAL MN. THIS FAR OUT...HAVE LEFT ANY
ADDITIONAL TS MENTION OUT...BUT WILL BE SOMETHING TO KEEP AN EYE
ON.
/OUTLOOK FOR KMSP/
TUE...VFR. WIND SW 5-10 KT...BECOMING W/NW IN AFTERNOON.
WED...VFR. WIND NE 5 KT.
THU...VFR. ISOLD SHRA/TS POSSIBLE. WINDS SE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ054>070-073>078-082>085-091>093.
HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ041>045-
047>053.
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ014>016-
023>028.
&&
$$
SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
1242 PM CDT SUN AUG 25 2013
.UPDATE...
HAVE JUST SENT OUT AN UPDATE TO ACCOUNT FOR RECENT AND EXPECTED
CONVECTIVE TRENDS. INSTABILITY IS BUILDING ACROSS THE REGION TODAY
WITH MARGINAL SHEAR OF 30 TO 40 KTS. WE ALSO HAVE A FAIRLY DECENT
CAP...WITH 700MB TEMPS OF 10C PLUS OVER MOST OF THE FORECAST AREA.
WE ARE GOING TO NEED A DECENT TRIGGER TO GET PAST ALL THAT.
SURFACE FEATURES AT THIS TIME ARE A LITTLE TOO WEAK...BUT THERE IS
A WEAK SHORTWAVE ON VISIBLE SATELLITE IMAGERY OVER NORTHERN SOUTH
DAKOTA...ASSOCIATED WITH A WEAK ENHANCEMENT ON WV SATELLITE
IMAGERY THAT MAY PROVIDE JUST ENOUGH LIFT TO GENERATE STORMS. IT
SHOULD BE MOVING INTO THE SOUTHWESTERN PORTIONS OF THE FORECAST
AREA AROUND 01Z THIS EVENING. IT WILL BE MOVING OVER THE VERY
UNSTABLE AIRMASS OVER EASTERN SOUTH DAKOTA HERE IN THE NEXT FEW
HOURS...SO IF IT IS GOING TO BE ABLE TO GENERATE CONVECTION WE
SHOULD KNOW SOON.
&&
.PREV DISCUSSION... /ISSUED 729 AM CDT SUN AUG 25 2013/
AVIATION...12Z TAF ISSUANCE...
STORMS WILL MOVE NEAR THE KHIB SITE EARLY MORNING SO HAVE INCLUDED
A VCTS THRU 14Z. OTHERWISE VFR CONDITIONS ARE EXPECTED TODAY. A WEAK
FRONT.. OR WINDSHIFT BDRY... WILL SINK SOUTH LATER TODAY FROM THE
BORDERLAND TOWARDS THE TWIN PORTS. THUNDERSTORMS ARE POSSIBLE ALONG
THIS BDRY LATER TODAY AND CONTINUING THIS EVENING. THERE IS A
POSSIBILITY THAT THE CONVECTION MAY HAVE A TOUGH TIME INITIATING
GIVEN THE EXTENT OF WARM AIR ALOFT. GIVEN LOWER CONFIDENCE IN
CONVECTION WE WILL USE PROB 30 BEGINNING LATE TODAY AT
KBRD/KDLH/KHYR TERMINALS. MAJORITY OF CONVECTION IS EXPECTED TO
REMAIN SOUTH OF KINL THIS PERIOD.
PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 25 2013/
UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. IT WILL BE HUMID WITH DEWPOINTS IN THE
UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY THE
SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE
WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.POINT TEMPS/POPS...
DLH 69 89 68 87 / 50 40 50 40
INL 61 88 67 86 / 0 40 60 30
BRD 69 94 72 91 / 50 40 50 20
HYR 71 92 71 92 / 60 50 50 30
ASX 69 85 68 86 / 50 40 50 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY UNTIL 9 PM CDT MONDAY FOR MNZ033>038.
WI...HEAT ADVISORY UNTIL 9 PM CDT MONDAY FOR WIZ001>004-006>009.
LS...NONE.
&&
$$
SHORT TERM...LE
AREA FORECAST DISCUSSION...CORRECTED
NWS DULUTH MN
729 AM CDT SUN AUG 25 2013
.AVIATION...12Z TAF ISSUANCE...
STORMS WILL MOVE NEAR THE KHIB SITE EARLY MORNING SO HAVE INCLUDED
A VCTS THRU 14Z. OTHERWISE VFR CONDITIONS ARE EXPECTED TODAY. A WEAK
FRONT.. OR WINDSHIFT BDRY... WILL SINK SOUTH LATER TODAY FROM THE
BORDERLAND TOWARDS THE TWIN PORTS. THUNDERSTORMS ARE POSSIBLE ALONG
THIS BDRY LATER TODAY AND CONTINUING THIS EVENING. THERE IS A
POSSIBILITY THAT THE CONVECTION MAY HAVE A TOUGH TIME INITIATING
GIVEN THE EXTENT OF WARM AIR ALOFT. GIVEN LOWER CONFIDENCE IN
CONVECTION WE WILL USE PROB 30 BEGINNING LATE TODAY AT
KBRD/KDLH/KHYR TERMINALS. MAJORITY OF CONVECTION IS EXPECTED TO
REMAIN SOUTH OF KINL THIS PERIOD.
&&
.PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 25 2013/
UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. IT WILL BE HUMID WITH DEWPOINTS IN THE
UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY THE
SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE
WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
AVIATION...CANNON
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
642 AM CDT SUN AUG 25 2013
.AVIATION...12Z TAF ISSUANCE...
STORMS WILL MOVE NEAR THE KHIB SITE EARLY MORNING SO HAVE INCLUDED
A VCTS THRU 14Z. OTHERWISE VFR CONDITIONS ARE EXPECTED TODAY. A WEAK
FRONT.. OR WINDSHIFT BDRY... WILL SINK SOUTH LATER TODAY FROM THE
BORDERLAND TOWARDS THE TWIN PORTS. THUNDERSTORMS ARE POSSIBLE ALONG
THIS BDRY LATER TODAY AND CONTINUING THIS EVENING. THERE IS A
POSSIBILITY THAT THE CONVECTION MAY HAVE A TOUGH TIME INITIATING
GIVEN THE EXTENT OF WARM AIR ALOFT. GIVEN LOWER CONFIDENCE IN
CONVECTION WE WILL USE PROB 30 BEGINNING LATE TODAY AT
KBRD/KDLH/KHYR TERMINALS. MAJORITY OF CONVECTION IS EXPECTED TO
REMAIN SOUTH OF KINL THIS PERIOD.
&&
.PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 25 2013/
UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. DULUTH MAY BREAK IT`S RECORD HIGH FOR THE
DATE...WHICH IS 90...AND INTERNATIONAL FALLS WILL BE CLOSE WITH
IT`S RECORD HIGH TODAY OF 92. IT WILL BE HUMID WITH DEWPOINTS IN
THE UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY
THE SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS DULUTH MN
604 AM CDT SUN AUG 25 2013
.UPDATE...
WE`VE HAD TO UPDATE GRIDS/PRODUCTS THIS MORNING TO ADD MORE
SHOWERS/STORMS ACROSS THE NORTHLAND FOR THE NEXT FEW HOURS. RADAR HAS
SHOWN AN INCREASE IN COVERAGE OVER CENTRAL MINNESOTA AND OVER
CROW WING/AITKIN COUNTIES. SOME STRONG STORMS WILL REMAIN POSSIBLE
FOR A COUPLE MORE HOURS. THE LATEST 08Z HRRR AS WELL AS THE
NMM/ARW HIRES MODELS SUGGEST MUCH OF THESE SHOWERS/STORMS WILL
DISSIPATE BY MID-LATE MORNING. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOWER THAN NORMAL SINCE THEY ARE NOT DOING A GOOD JOB
WITH THE CURRENT CONVECTION.
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT SUN AUG 25 2013/
SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. DULUTH MAY BREAK IT`S RECORD HIGH FOR THE
DATE...WHICH IS 90...AND INTERNATIONAL FALLS WILL BE CLOSE WITH
IT`S RECORD HIGH TODAY OF 92. IT WILL BE HUMID WITH DEWPOINTS IN
THE UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY
THE SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
AVIATION...06Z TAF ISSUANCE.
VFR CONDITIONS WILL PREVAIL MOST OF THE FCST PERIOD EXCEPT IN THE
NRN TIER OF MN WHERE LOCAL MVFR/IFR MAY OCCUR IN LOWER CLOUD
DEVELOPMENT AND HEAVIER STORMS EARLY THIS MORNING. A WEAK SFC BDRY
WILL TRY TO PUSH SOUTH ACROSS THE AREA TODAY. MID LVL WARMTH
SHOULD MAKE CONVECTION TOUGH TO DEVELOP. AMENDMENTS MAY BE
REQUIRED GIVEN UNCERTAINTY OF CONVECTIVE DEVELOPMENT. LLWS AT
KBRD/KHYR AS 45/50KT LLJ TRANSLATES EAST THROUGH 12Z.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM....CANNON
AREA FORECAST DISCUSSION
NWS DULUTH MN
349 AM CDT SUN AUG 25 2013
.SHORT TERM...THROUGH EARLY MONDAY EVENING.
HOT AND HUMID CONDITIONS WILL COVER MUCH OF THE NORTHLAND TODAY.
THE LARGE UPPER HIGH OVER THE CENTRAL CONUS WILL REMAIN THROUGH
THE SHORT TERM...WITH A COUPLE DIFFERENT FEATURES MOVING THROUGH
BRINGING A THREAT FOR SHOWERS/STORMS.
AS OF 0830Z...A FEW THUNDERSTORMS WERE OCCURRING OVER FAR NORTHERN
MINNESOTA DUE TO A PASSING WAVE AND WAA WITH SOUTHWESTERLY LLJ.
KDLH`S VWP SHOWED 35 KT AT 925MB WITH WEST WINDS AT 850MB OF 50
KT. STRONG THUNDERSTORMS WERE OCCURRING OVER EASTERN NORTH DAKOTA
IN AN AREA OF LOW LEVEL CONVERGENCE ALONG A WEAK FRONTAL BOUNDARY.
THE AIRMASS IS PLENTY UNSTABLE THIS MORNING WITH MUCAPES OF
1000-2000J/KG AND MLCAPES OF 500-1500J/KG. WARM LOW-MID LEVEL
TEMPS COVERED THE CWA...WITH THE MODELS SHOWING 700MB TEMPS OF +10
TO +12C. THE 00Z KINL SOUNDING HAD +11C AT 700MB. WE EXPECT THE
NORTHERN MINNESOTA SHOWERS/STORMS TO CONTINUE EAST EARLY THIS
MORNING...WITH SOUTHWARD DEVELOPMENT LOOKING LESS LIKELY. THE LOW
LEVEL CONVERGENT AREA AS FORECAST BY THE RAP AT 925MB...MAY ALLOW
FOR SOME ADDITIONAL DEVELOPMENT OVER PORTIONS OF OUR
WEST/SOUTHWEST PRIOR TO 12Z...BUT MORE LIKELY AFTER THAT TIME.
THERE WILL BE A BATTLE BETWEEN THE LIFT FROM THE APPROACHING
TROUGH AND THE WARM MID LEVEL TEMPS TODAY. WE DO KEEP SOME LOW
POPS OVER CENTRAL PORTIONS OF THE CWA...THEN INCREASE FURTHER
LATER THIS AFTERNOON WITH MAX HEATING...THE LOW LEVEL TROUGH AND
PERHAPS A WEAK WAVE ALL CONTRIBUTING TO LIFT. THE STORMS COULD BE
SEVERE OVER THE SOUTHERN HALF OF THE NORTHLAND THIS AFTERNOON INTO
TONIGHT.
WE STILL EXPECT HIGHS TO REACH THE LOWER TO MIDDLE NINETIES OVER
MUCH OF THE NORTHLAND. DULUTH MAY BREAK IT`S RECORD HIGH FOR THE
DATE...WHICH IS 90...AND INTERNATIONAL FALLS WILL BE CLOSE WITH
IT`S RECORD HIGH TODAY OF 92. IT WILL BE HUMID WITH DEWPOINTS IN
THE UPPER SIXTIES TO LOWER SEVENTIES. WE KEPT THE HEAT ADVISORY
THE SAME. AREAS AROUND LAKE SUPERIOR...EXCEPT FOR PERHAPS UP INTO
COASTAL COOK COUNTY...WILL ALSO BE HOT TODAY DUE TO OFFSHORE WINDS.
MONDAY WILL REMAIN HOT WITH HIGHS FROM THE UPPER EIGHTIES TO LOWER
NINETIES. AREAS ALONG LAKE SUPERIOR WILL BE COOLER THOUGH...AS AN
ONSHORE FLOW DEVELOPS DUE TO LOW PRESSURE OUT TO THE WEST AND A
WEAK HIGH TO THE EAST. A WARM FRONT WILL BE DRAPED FROM WEST TO
EAST ACROSS THE NORTHLAND. WE INTRODUCED SOME POPS ALONG THIS
FEATURE OVER ALL BUT FAR NORTHERN MINNESOTA ON MONDAY. CONVERGENCE
IS WEAK...BUT WE CAN`T RULE OUT SOME THUNDERSTORM DEVELOPMENT WITH
PEAK HEATING.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY.
A LARGE SFC/MID LVL RIDGE WILL PREVAIL OVER THE SRN PLAINS THROUGH
THE WEEK WITH UNUSUALLY HOT AND MUGGY WEATHER EXPECTED ACROSS THE
NORTHLAND. THE HEAT WILL BE TEMPERED BRIEFLY BY THE PASSAGE OF A
FRONTAL SYSTEM MON NIGHT AND EARLY TUESDAY. THIS WILL BE THE BEST
CHANCE FOR MUCH NEEDED PRECIP ACROSS THE CTRL/SRN CWA. HOWEVER...THE
PRESENCE OF THE ANOMALOUS RIDGE AT MID LVLS WITH AN ASSOCIATED MID
LVL WARM LAYER MAKES THE CONVECTIVE OPPORTUNITIES QUESTIONABLE. MOST
LIKELY AREA WILL BE NRN MN ZONES AHEAD OF WARM FRONTAL BDRY MONDAY
NIGHT AND ON NRN FRINGES OF NORTHWARD ADVECTING MID LVL CAP. SFC
COLD FRONT WILL PASS THROUGH TUESDAY HOWEVER EXTENSIVE CIN IS
EXPECTED BY EARLY AFTN SO POPS LOWERED. HIGH PRESSURE IS EXPECTED TO
PASS ACROSS THE AREA WED/WED NIGHT. A TEMPORARY REDUCTION IN
HUMIDITY SHOULD OCCUR BEFORE SFC HIGH MOVES EAST THURSDAY.
HEAT/HUMIDITY INCREASE LATE WEEK INTO WEEKEND AS WARM ADVECTION
RESUMES. LOW POPS LATE WEEK AND INTO WEEKEND AS UPPER JET REMAINS
NORTH OF CWA AND MAIN CONVECTION CHANCES ARE POSITIONED NORTH AND
WEST OF CWA.
&&
.AVIATION...06Z TAF ISSUANCE.
VFR CONDITIONS WILL PREVAIL MOST OF THE FCST PERIOD EXCEPT IN THE
NRN TIER OF MN WHERE LOCAL MVFR/IFR MAY OCCUR IN LOWER CLOUD
DEVELOPMENT AND HEAVIER STORMS EARLY THIS MORNING. A WEAK SFC BDRY
WILL TRY TO PUSH SOUTH ACROSS THE AREA TODAY. MID LVL WARMTH
SHOULD MAKE CONVECTION TOUGH TO DEVELOP. AMENDMENTS MAY BE
REQUIRED GIVEN UNCERTAINTY OF CONVECTIVE DEVELOPMENT. LLWS AT
KBRD/KHYR AS 45/50KT LLJ TRANSLATES EAST THROUGH 12Z.
&&
.POINT TEMPS/POPS...
DLH 92 69 89 68 / 40 50 20 50
INL 87 61 88 67 / 20 10 10 60
BRD 96 69 94 72 / 30 50 20 40
HYR 94 71 92 71 / 40 60 20 50
ASX 93 69 85 68 / 40 50 20 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
MNZ033>038.
WI...HEAT ADVISORY FROM 11 AM THIS MORNING TO 9 PM CDT MONDAY FOR
WIZ001>004-006>009.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM....CANNON
AVIATION...CLC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
256 PM EDT SUN AUG 25 2013
.SYNOPSIS...
AN APPROACHING FRONTAL SYSTEM WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT AND MONDAY. DRY WEATHER IS FORECAST FOR
TUESDAY...BUT MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
TUESDAY NIGHT AND WEDNESDAY AS ANOTHER COLD FRONT MOVES THROUGH
THE REGION. AFTER THIS FRONT PASSES BY...FAIR WEATHER IS EXPECTED
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
UDPATED THE NEAR TEAM TO BRING POPS IN ERLR FROM THE MCS THAT IS
MOVING ACRS ONT AND QUE AND THE NERN GREAT LAKES. THE HRRR HAS
BEEN SHOWING THAT THIS PRECIP WILL GET INTO NC AND EC NY BETWEEN
1Z AND 6Z WITH THE RAP NOW SPEEDING THE ARRIVAL UP TOO OVER THE
OTHER MODELS. SINCE THESE ARE RAPID UPDATE CYCLE MODELS AND THE
RADAR TRENDS ARE CLSR TO THESE MODELS I NOW BRING IN PRECIP MUCH
ERLR IN LINE WITH KBUF/S RECENT UPDATE. OTHERWISE...NO OTHER
CHANGES THRU MONDAY.
PREVIOUS DSCN BELOW...
VISIBLE SATL IMAGERY SHOWS SCT CUMULUS FORMING WITH INSOLATION.
SOME CIRRUS FROM AN UPSTREAM MCS OVER NRN AND CNTRL ONTARIO AND
THE UPPER LAKES WILL STREAM SOUTHEASTWARD FOR THE REST OF THE
AFTERNOON....THUS SKIES WILL BE PS TO MS. CANADIAN RADAR LOOP
SHOWS AN MCS WITH SHOWERS AND THUNDERSTORMS TRACKING SEWRD ACRS
GEORGIAN BAY AND TWD SERN ONTARIO INTO WRN QUEBEC. CONVECTION
ALLOWING MESOSCALE MODELS ...WRF-NMM, WRF-ARW AND HRRR ALL SHOW
THE SRN EDGE OF THE PRECIPITATION SHIELD WITH THIS MCS SKIRTING
ACRS NRN AND ERN NY TONIGHT WITH ELEVATED INSTABILITY REMAINING ON
THE BACK EDGE OF THE MCS AS IT WORKS SEWRD. THE MAIN QUESTION IS
TIMING. LATEST WRF-NMM AND WRF-ARW BOTH HAVE SHRA AND TSRA
ARRIVING AFTER 6Z...MAINLY 9-12Z ACRS NC NY SEWRD TO THE
CATSKILLS. THE HRRR ON THE OTHER HAND HAS THE PRECIP SHIELD AND
SOME TSRA ARRIVING MUCH ERLR...SPREADING FROM NC NY SOUTHWARD TO
THE CATSKILLS AND EVEN NE PA BETWEEN 1Z AND 6Z ABT 4-6 HOURS
SOONER. TTHE NAM...GFS AND CANADIAN ALL BRING SOME LIGHT PRECIP
INTO THESE AREAS LATE TONIGHT WITH THE RUC A LITTLE FASTER ON THE
ARRIVAL OF THE PRECIP. THUS THE HRRR AND THE RUC TO A LESSER
EXTENT AERE ON AN ISLAND BY THEMSELVES. HOWEVER...JUDGING BY
LATEST RADAR LOOP IT LOOKS LIKE THE HRRR HAS THE BEST HANDLE...BUT
THIS IS A MAJOR DEPARTURE FROM ERLR FCSTS AND ALL OTHER MODEL
GUIDC AND SOUNDINGS INDICATE THAT IT IS VERY DRY BELOW 10000 FEET.
SO FOR NOW WILL HAVE CHC POPS NRN AND ERN CWA INCREASING AFTR
6Z...BUT WILL RE-EVALUATE AND MAY HAVE TO BUMP UP POPS ERLR. I WUD
LIKE TO SEE RADAR TRENDS ON THE SRN EDGE OF THIS MCS AND IF THE
PRECIP IS REACHING THE GRND NEXT COUPLE HOURS.
FOR MONDAY...AN UPPER LEVEL WAVE WILL MOVE EASTWARD TWD NY AND PA
IN THE NW UPPER LEVEL FLO PATTERN. CONVECTION ALLOWING
MODELS...ESPECIALLY THE WRF-NMM, AND WRF-ARW AS WELL AS THE NAM
AND HIGHER RES CANADIAN ALL INDICATE SOME POTENTIAL FOR TRAINING
THUNDERSTORMS AS THE LL FLOW WILL BE W-NW AND FAIRLY ALIGNED WITH
THE UPPER LEVEL FLO. BOTH THE CANADIAN AND NAM HAVE A WELL
DEVELOPED JET ENTRANCE REGION CIRCULATION FOR OUR AREA WHEREAS THE
ERLR EURO AND 12Z GFS REALLY DON/T. MODEL CAPES ARE AVERAGING
ARND 1000 J/KG OR SO WITH MODEST SHEAR VALUES...GENERALLY 25 TO 30
KNOTS IN THE LOWEST 6 KM WITH MOST OF THE SHEAR ACTUALLY BETWEEN 0
AND 3 KM. I CAN EASILY SEE AN MCS EVOLVING OVER OUR REGION MON PM
AND...IN ITS WAKE SOME TRAINING STORMS WITH LOCALLY HEAVY RAINS.
FOR NOW...THINK LIKELY POPS ARE ON ORDER MON PM. THERE IS WAY TOO
MUCH UNCERTAINTY AS TO HEAVY RAINFALL POTENTIAL. NAM AND CMC GIVE
THE REGION A STRIPE OF 1-2 INCHES OF RAIN WHICH SHUDN/T BE MUCH OF
A PROBLEM AT ALL. HOWEVER WILL ALERT FUTURE SHIFTS FOR POTENTIAL
TO RAISE SITUATIONAL AWARENESS. AS FOR SEVERE POTENTIAL...THERE CUD BE
SOME LOCALLY DAMAGING WINDS...BUT AT THIS POINT IT LOOKS LIKE THE
CAPE AND SHEAR FALL SHORT OF WHAT WE WOULD EXPECT FOR AN OUTBREAK.
SPC CONCURS IN THEIR DAY 2 OUTLOOK.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
I KEPT TUESDAY DRY AS NY AND PA IS IN BETWEEN SYSTEMS WITH A SMALL
BUBBLE HIGH OVERHD. ALL SYNOPTIC MODELS INDICATE THAT THE MAJORITY
OF THE DAY IS DRY WITH JUST A FEW HUNDRENTHS POSSIBLE IN THE SW
AND FAR NE PART OF OUR CWA.
FOR WEDNESDAY...MODELS ARE IN AGREEMENT THAT ANOTHER MCS AND SHRT
WAVE WILL AFFECT THE REGION. MODEL TIMING AND PLACEMENT IS
UNCERTAIN THIS FAR OUT. SO I HAVE GENERIC CHC POPS FOR SHRA AND
TSRA TO COVER IN LINE WITH NEIGHBORING OFFICES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
NO MAJOR CHANGES TO THIS PART OF THE FORECAST. THE BROAD...AND
HOT LATE SEASON RIDGE OVER MUCH OF THE WESTERN AND CNTRL CONUS IS
STILL EXPECTED TO EXPAND INTO THE NORTHEAST BY THE END OF THE
PERIOD WITH REGIONAL HIGH TEMPERATURES EXPECTED TO RISE WELL INTO
THE MID 80S OVER NEXT WEEKEND.
THE ADVERTISED FRONTAL SYSTEM...POSSIBLY ACCOMPANIED BY A COMPLEX
SECONDARY LOW DEVELOPMENT ON THE BOUNDARY...IS STILL FORECAST TO
BE MOVING EAST OF THE AREA IN THE WEDNESDAY NIGHT-THURSDAY TIME
FRAME. THE FORECAST WILL STILL FEATURE DECREASING POPS WITH TIME
INTO THURSDAY...THEN WITH THE BROAD RIDGE IN PLACE THURSDAY NIGHT
AND NEXT WEEKEND LOOKS RAIN FREE AND WARMER AT THIS TIME.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
FOR A GENERALLY VFR SITUATION...THIS FORECAST HAS SOME INTERESTING
WRINKLES BUILT IN. A RATHER STUBBORN THUNDERSTORM COMPLEX MOVING
THROUGH THE UPPER GREAT LAKES REGION THIS AFTERNOON LOOKS TO BE
TARGETING OUR TERMINALS FOR THIS EVENING. THE SYSTEM WILL LOSE A LOT
OF IT`S CONVECTIVE PUNCH AS IT PULLS AWAY FROM THE SOURCE REGION
OF BEST INSTABILITY OVER THE UPPER MIDWEST AND WESTERN ONTARIO...BUT
WILL STILL LIKELY BRING IN SOME MID LVL CIGS AND POSSIBLE SHOWERS.
LINEAR EXTRAPOLATION BRINGS THE LEADING EDGE OF SYSTEM INTO THE
KSYR-KRME-KITH AREAS TOWARD 00Z WITH SHOWER POTENTIAL FOR A FEW
HOURS THEREAFTER. NOT SURE IF MUCH RAIN WILL REACH THE GROUND AS
LAYERS BETWEEN 5K-10K FT ARE PRETTY DRY. COULD TURN OUT TO BE JUST
INSIGNIFICANT -SHRA FROM THE MID DECK.
LATER ON TONIGHT...THE SWLY FLOW ALOFT DOES TEND TO MOISTEN UP THE
LOWER LEVELS OF THE ATMOSPHERE WITH CIGS PROBABLY LOWERING INTO
THE 5 KFT RANGE BY MORNING. THERE STANDS TO BE ANOTHER ROUND OF
SHOWERS DEVELOPING TOWARD MORNING AS MINOR UPPER LEVEL IMPULSES
MOVE THROUGH THE NORTHWESTERLY JET LEVEL FLOW. MVFR SHOULD BE
LIMITED TO MAYBE SOME LIGHT FOG AT KELM...ALTHOUGH THERE IS SOME
CHANCE FOR LOWER CIGS IN ANY RAIN SHOWERS, BUT THE CONFIDENCE FOR
INCLUDING THAT IN THE FORECAST IS PRETTY LOW.
WINDS GENERALLY LIGHT SOUTHWEST...OR VARIABLE DRAINAGE FLOW IS
EXPECTED THROUGH TONIGHT...THEN INCREASING SW-W UP TO 10 KTS ON
MONDAY.
OUTLOOK...
MON...VFR. OCNL SHRA. CHC TSRA IN PM.
TUE...VFR. CHC SHRA/TSRA PM. LOCAL MVFR.
WED...VFR. SHRA/TSRA LIKELY. CHC MVFR.
THU...VFR.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
226 PM EDT SUN AUG 25 2013
.SYNOPSIS...
AN APPROACHING FRONTAL SYSTEM WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT AND MONDAY. DRY WEATHER IS FORECAST FOR
TUESDAY...BUT MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
TUESDAY NIGHT AND WEDNESDAY AS ANOTHER COLD FRONT MOVES THROUGH
THE REGION. AFTER THIS FRONT PASSES BY...FAIR WEATHER IS EXPECTED
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
VISIBLE SATL IMAGERY SHOWS SCT CUMULUS FORMING WITH INSOLATION.
SOME CIRRUS FROM AN UPSTREAM MCS OVER NRN AND CNTRL ONTARIO AND
THE UPPER LAKES WILL STREAM SOUTHEASTWARD FOR THE REST OF THE
AFTERNOON....THUS SKIES WILL BE PS TO MS. CANADIAN RADAR LOOP
SHOWS AN MCS WITH SHOWERS AND THUNDERSTORMS TRACKING SEWRD ACRS
GEORGIAN BAY AND TWD SERN ONTARIO INTO WRN QUEBEC. CONVECTION
ALLOWING MESOSCALE MODELS ...WRF-NMM, WRF-ARW AND HRRR ALL SHOW
THE SRN EDGE OF THE PRECIPITATION SHIELD WITH THIS MCS SKIRTING
ACRS NRN AND ERN NY TONIGHT WITH ELEVATED INSTABILITY REMAINING
ON THE BACK EDGE OF THE MCS AS IT WORKS SEWRD. THE MAIN QUESTION
IS TIMING. LATEST WRF-NMM AND WRF-ARW BOTH HAVE SHRA AND TSRA
ARRIVING AFTER 6Z...MAINLY 9-12Z ACRS NC NY SEWRD TO THE
CATSKILLS. THE HRRR ON THE OTHER HAND HAS THE PRECIP SHIELD AND
SOME TSRA ARRIVING MUCH ERLR...SPREADING FROM NC NY SOUTHWARD TO
THE CATSKILLS AND EVEN NE PA BETWEEN 1Z AND 6Z ABT 4-6 HOURS
SOONER. TTHE NAM...GFS AND CANADIAN ALL BRING SOME LIGHT PRECIP
INTO THESE AREAS LATE TONIGHT WITH THE RUC A LITTLE FASTER ON THE
ARRIVAL OF THE PRECIP. THUS THE HRRR AND THE RUC TO A LESSER
EXTENT AERE ON AN ISLAND BY THEMSELVES. HOWEVER...JUDGING BY LATEST RADAR
LOOP IT LOOKS LIKE THE HRRR HAS THE BEST HANDLE...BUT THIS IS A
MAJOR DEPARTURE FROM ERLR FCSTS AND ALL OTHER MODEL GUIDC AND
SOUNDINGS INDICATE THAT IT IS VERY DRY BELOW 10000 FEET. SO FOR
NOW WILL HAVE CHC POPS NRN AND ERN CWA INCREASING AFTR 6Z...BUT
WILL RE-EVALUATE AND MAY HAVE TO BUMP UP POPS ERLR. I WUD LIKE TO
SEE RADAR TRENDS ON THE SRN EDGE OF THIS MCS AND IF THE PRECIP IS
REACHING THE GRND NEXT COUPLE HOURS.
FOR MONDAY...AN UPPER LEVEL WAVE WILL MOVE EASTWARD TWD NY AND PA
IN THE NW UPPER LEVEL FLO PATTERN. CONVECTION ALLOWING
MODELS...ESPECIALLY THE WRF-NMM, AND WRF-ARW AS WELL AS THE NAM
AND HIGHER RES CANADIAN ALL INDICATE SOME POTENTIAL FOR TRAINING
THUNDERSTORMS AS THE LL FLOW WILL BE W-NW AND FAIRLY ALIGNED WITH
THE UPPER LEVEL FLO. BOTH THE CANADIAN AND NAM HAVE A WELL
DEVELOPED JET ENTRANCE REGION CIRCULATION FOR OUR AREA WHEREAS THE
ERLR EURO AND 12Z GFS REALLY DON/T. MODEL CAPES ARE AVERAGING
ARND 1000 J/KG OR SO WITH MODEST SHEAR VALUES...GENERALLY 25 TO 30
KNOTS IN THE LOWEST 6 KM WITH MOST OF THE SHEAR ACTUALLY BETWEEN 0
AND 3 KM. I CAN EASILY SEE AN MCS EVOLVING OVER OUR REGION MON PM
AND...IN ITS WAKE SOME TRAINING STORMS WITH LOCALLY HEAVY RAINS.
FOR NOW...THINK LIKELY POPS ARE ON ORDER MON PM. THERE IS WAY TOO
MUCH UNCERTAINTY AS TO HEAVY RAINFALL POTENTIAL. NAM AND CMC GIVE
THE REGION A STRIPE OF 1-2 INCHES OF RAIN WHICH SHUDN/T BE MUCH OF
A PROBLEM AT ALL. HOWEVER WILL ALERT FUTURE SHIFTS FOR POTENTIAL
TO RAISE SITUATIONAL AWARENESS. AS FOR SEVERE POTENTIAL...THERE CUD BE
SOME LOCALLY DAMAGING WINDS...BUT AT THIS POINT IT LOOKS LIKE THE
CAPE AND SHEAR FALL SHORT OF WHAT WE WOULD EXPECT FOR AN OUTBREAK.
SPC CONCURS IN THEIR DAY 2 OUTLOOK.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LINGERING SHRA/TSRA PSBL MON EVNG AS FNTL SYSTEM DEPARTS AND WEAK
HI PRES BUILDS INTO THE RGN. NAM/GFS PROFILES BOTH SHOW FAIRLY SIG
LOW LVL MSTR BEHIND THIS BNDRY PERSISTING INTO TUE MRNG...WHICH
SHUD BURN OFF BY LATE MRNG LEAVING PS SKIES.
THE NXT S/WV AND FNTL SYSTEM APRCHS TUE NGT. ALL MDLS SUGGEST MCS
POTNL BUT THERE ARE SIG DIFFS W/RESPECT TO THE TRACK OF THE SFC
LOW/MCS. GFS/NAM SUGGEST A MORE SWD TRACK OF THE LOW AND
MCS...WHILE THE EURO/GEM INDICATE A MORE NRLY TRACK. NO DOUBT
LATER FCSTS WILL BE TWEAKED AS WE GET CLOSER TO THE EVENT...SO FOR
NOW WENT WITH MOS POPS (CHC) FOR THESE TIME PDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
NO MAJOR CHANGES TO THIS PART OF THE FORECAST. THE BROAD...AND
HOT LATE SEASON RIDGE OVER MUCH OF THE WESTERN AND CNTRL CONUS IS
STILL EXPECTED TO EXPAND INTO THE NORTHEAST BY THE END OF THE
PERIOD WITH REGIONAL HIGH TEMPERATURES EXPECTED TO RISE WELL INTO
THE MID 80S OVER NEXT WEEKEND.
THE ADVERTISED FRONTAL SYSTEM...POSSIBLY ACCOMPANIED BY A COMPLEX
SECONDARY LOW DEVELOPMENT ON THE BOUNDARY...IS STILL FORECAST TO
BE MOVING EAST OF THE AREA IN THE WEDNESDAY NIGHT-THURSDAY TIME
FRAME. THE FORECAST WILL STILL FEATURE DECREASING POPS WITH TIME
INTO THURSDAY...THEN WITH THE BROAD RIDGE IN PLACE THURSDAY NIGHT
AND NEXT WEEKEND LOOKS RAIN FREE AND WARMER AT THIS TIME.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
FOR A GENERALLY VFR SITUATION...THIS FORECAST HAS SOME INTERESTING
WRINKLES BUILT IN. A RATHER STUBBORN THUNDERSTORM COMPLEX MOVING
THROUGH THE UPPER GREAT LAKES REGION THIS AFTERNOON LOOKS TO BE
TARGETING OUR TERMINALS FOR THIS EVENING. THE SYSTEM WILL LOSE A LOT
OF IT`S CONVECTIVE PUNCH AS IT PULLS AWAY FROM THE SOURCE REGION
OF BEST INSTABILITY OVER THE UPPER MIDWEST AND WESTERN ONTARIO...BUT
WILL STILL LIKELY BRING IN SOME MID LVL CIGS AND POSSIBLE SHOWERS.
LINEAR EXTRAPOLATION BRINGS THE LEADING EDGE OF SYSTEM INTO THE
KSYR-KRME-KITH AREAS TOWARD 00Z WITH SHOWER POTENTIAL FOR A FEW
HOURS THEREAFTER. NOT SURE IF MUCH RAIN WILL REACH THE GROUND AS
LAYERS BETWEEN 5K-10K FT ARE PRETTY DRY. COULD TURN OUT TO BE JUST
INSIGNIFICANT -SHRA FROM THE MID DECK.
LATER ON TONIGHT...THE SWLY FLOW ALOFT DOES TEND TO MOISTEN UP THE
LOWER LEVELS OF THE ATMOSPHERE WITH CIGS PROBABLY LOWERING INTO
THE 5 KFT RANGE BY MORNING. THERE STANDS TO BE ANOTHER ROUND OF
SHOWERS DEVELOPING TOWARD MORNING AS MINOR UPPER LEVEL IMPULSES
MOVE THROUGH THE NORTHWESTERLY JET LEVEL FLOW. MVFR SHOULD BE
LIMITED TO MAYBE SOME LIGHT FOG AT KELM...ALTHOUGH THERE IS SOME
CHANCE FOR LOWER CIGS IN ANY RAIN SHOWERS, BUT THE CONFIDENCE FOR
INCLUDING THAT IN THE FORECAST IS PRETTY LOW.
WINDS GENERALLY LIGHT SOUTHWEST...OR VARIABLE DRAINAGE FLOW IS
EXPECTED THROUGH TONIGHT...THEN INCREASING SW-W UP TO 10 KTS ON
MONDAY.
OUTLOOK...
MON...VFR. OCNL SHRA. CHC TSRA IN PM.
TUE...VFR. CHC SHRA/TSRA PM. LOCAL MVFR.
WED...VFR. SHRA/TSRA LIKELY. CHC MVFR.
THU...VFR.
FRI...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...JAB
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
138 PM EDT SUN AUG 25 2013
.SYNOPSIS...
AN APPROACHING FRONTAL SYSTEM WILL BRING A SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT AND MONDAY. DRY WEATHER IS FORECAST FOR
TUESDAY...BUT MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
TUESDAY NIGHT AND WEDNESDAY AS ANOTHER COLD FRONT MOVES THROUGH
THE REGION. AFTER THIS FRONT PASSES BY...FAIR WEATHER IS EXPECTED
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
VISIBLE SATL IMAGERY SHOWS SCT CUMULUS FORMING WITH INSOLATION.
SOME CIRRUS FROM AN UPSTREAM MCS OVER NRN AND CNTRL ONTARIO AND
THE UPPER LAKES WILL STREAM SOUTHEASTWARD FOR THE REST OF THE
AFTERNOON....THUS SKIES WILL BE PS TO MS. CANADIAN RADAR LOOP
SHOWS AN MCS WITH SHOWERS AND THUNDERSTORMS TRACKING SEWRD ACRS
GEORGIAN BAY AND TWD SERN ONTARIO INTO WRN QUEBEC. CONVECTION
ALLOWING MESOSCALE MODELS ...WRF-NMM, WRF-ARW AND HRRR ALL SHOW
THE SRN EDGE OF THE PRECIPITATION SHIELD WITH THIS MCS SKIRTING
ACRS NRN AND ERN NY TONIGHT WITH ELEVATED INSTABILITY REMAINING
ON THE BACK EDGE OF THE MCS AS IT WORKS SEWRD. THE MAIN QUESTION
IS TIMING. LATEST WRF-NMM AND WRF-ARW BOTH HAVE SHRA AND TSRA
ARRIVING AFTER 6Z...MAINLY 9-12Z ACRS NC NY SEWRD TO THE
CATSKILLS. THE HRRR ON THE OTHER HAND HAS THE PRECIP SHIELD AND
SOME TSRA ARRIVING MUCH ERLR...SPREADING FROM NC NY SOUTHWARD TO
THE CATSKILLS AND EVEN NE PA BETWEEN 1Z AND 6Z ABT 4-6 HOURS
SOONER. TTHE NAM...GFS AND CANADIAN ALL BRING SOME LIGHT PRECIP
INTO THESE AREAS LATE TONIGHT WITH THE RUC A LITTLE FASTER ON THE
ARRIVAL OF THE PRECIP. THUS THE HRRR AND THE RUC TO A LESSER
EXTENT AERE ON AN ISLAND BY THEMSELVES. HOWEVER...JUDGING BY LATEST RADAR
LOOP IT LOOKS LIKE THE HRRR HAS THE BEST HANDLE...BUT THIS IS A
MAJOR DEPARTURE FROM ERLR FCSTS AND ALL OTHER MODEL GUIDC AND
SOUNDINGS INDICATE THAT IT IS VERY DRY BELOW 10000 FEET. SO FOR
NOW WILL HAVE CHC POPS NRN AND ERN CWA INCREASING AFTR 6Z...BUT
WILL RE-EVALUATE AND MAY HAVE TO BUMP UP POPS ERLR. I WUD LIKE TO
SEE RADAR TRENDS ON THE SRN EDGE OF THIS MCS AND IF THE PRECIP IS
REACHING THE GRND NEXT COUPLE HOURS.
FOR MONDAY...AN UPPER LEVEL WAVE WILL MOVE EASTWARD TWD NY AND PA
IN THE NW UPPER LEVEL FLO PATTERN. CONVECTION ALLOWING
MODELS...ESPECIALLY THE WRF-NMM, AND WRF-ARW AS WELL AS THE NAM
AND HIGHER RES CANADIAN ALL INDICATE SOME POTENTIAL FOR TRAINING
THUNDERSTORMS AS THE LL FLOW WILL BE W-NW AND FAIRLY ALIGNED WITH
THE UPPER LEVEL FLO. BOTH THE CANADIAN AND NAM HAVE A WELL
DEVELOPED JET ENTRANCE REGION CIRCULATION FOR OUR AREA WHEREAS THE
ERLR EURO AND 12Z GFS REALLY DON/T. MODEL CAPES ARE AVERAGING
ARND 1000 J/KG OR SO WITH MODEST SHEAR VALUES...GENERALLY 25 TO 30
KNOTS IN THE LOWEST 6 KM WITH MOST OF THE SHEAR ACTUALLY BETWEEN 0
AND 3 KM. I CAN EASILY SEE AN MCS EVOLVING OVER OUR REGION MON PM
AND...IN ITS WAKE SOME TRAINING STORMS WITH LOCALLY HEAVY RAINS.
FOR NOW...THINK LIKELY POPS ARE ON ORDER MON PM. THERE IS WAY TOO
MUCH UNCERTAINTY AS TO HEAVY RAINFALL POTENTIAL. NAM AND CMC GIVE
THE REGION A STRIPE OF 1-2 INCHES OF RAIN WHICH SHUDN/T BE MUCH OF
A PROBLEM AT ALL. HOWEVER WILL ALERT FUTURE SHIFTS FOR POTENTIAL
TO RAISE SITUATIONAL AWARENESS. AS FOR SEVERE POTENTIAL...THERE CUD BE
SOME LOCALLY DAMAGING WINDS...BUT AT THIS POINT IT LOOKS LIKE THE
CAPE AND SHEAR FALL SHORT OF WHAT WE WOULD EXPECT FOR AN OUTBREAK.
SPC CONCURS IN THEIR DAY 2 OUTLOOK.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LINGERING SHRA/TSRA PSBL MON EVNG AS FNTL SYSTEM DEPARTS AND WEAK
HI PRES BUILDS INTO THE RGN. NAM/GFS PROFILES BOTH SHOW FAIRLY SIG
LOW LVL MSTR BEHIND THIS BNDRY PERSISTING INTO TUE MRNG...WHICH
SHUD BURN OFF BY LATE MRNG LEAVING PS SKIES.
THE NXT S/WV AND FNTL SYSTEM APRCHS TUE NGT. ALL MDLS SUGGEST MCS
POTNL BUT THERE ARE SIG DIFFS W/RESPECT TO THE TRACK OF THE SFC
LOW/MCS. GFS/NAM SUGGEST A MORE SWD TRACK OF THE LOW AND
MCS...WHILE THE EURO/GEM INDICATE A MORE NRLY TRACK. NO DOUBT
LATER FCSTS WILL BE TWEAKED AS WE GET CLOSER TO THE EVENT...SO FOR
NOW WENT WITH MOS POPS (CHC) FOR THESE TIME PDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
4 AM SUN UPDATE... NOT MUCH CHG TO THE PREV FCST...AS EC/GFS/WPC
CONSENSUS STILL SHOWS AN EXPANSIVE SUBTROP UPR RIDGE TO BE THE
MAIN WX INFLUENCE OVER MUCH OF THE CONUS THIS PD. ALTHOUGH THIS
RIDGE IS INITIALLY CENTERED OVER THE MIDDLE OF THE COUNTRY AT MID-
WEEK (START OF THE PD)...IT IS PROGGED TO SLOWLY EXPAND EWD WITH
TIME BY NEXT WEEKEND. AS A RESULT...SEASONABLE TEMPS WED-FRI
(HIGHS FROM THE MID 70S-LWR 80S) SHOULD WARM MORE SOLIDLY INTO THE
80S THEREAFTER.
AS FOR THE DAILY SENSIBLE WX...A COLD FRNTL BNDRY IS STILL
EXPECTED TO CROSS NY/PA FROM NW TO SE SOMETIME LTR WED OR EARLY
THU...WITH SHWRS/TSTMS ALG AND AHD OF THIS FEATURE. AS THIS SYSTEM
IS STILL SVRL DAYS AWAY...WE`LL CONTINUE TO ADVERTISE CHC POPS FOR
NOW ON WED AND WED NGT...DECREASING WITH TIME BY THU. FROM FRI
THROUGH NEXT WEEKEND...RAIN-FREE CONDS LOOK PROBABLE...WITH
RIDGING BUILDING IN BOTH SFC AND ALOFT.
PREV DISC... ECMWF AND GFS IN PRETTY GOOD AGREEMENT REGARDING A
STRONG RIDGE BUILDING THROUGHOUT THE CENTRAL U.S. AND EVENTUALLY
SPREADING ITS INFLUENCE EASTWARD.
A TROF WILL EXTEND ACROSS THE GREAT LAKES TUESDAY NIGHT, WITH AN
ASSOCIATED SFC CYCLONE AND COLD FRONT PROGGED TO PULL THROUGH
NY/PA ON WEDNESDAY. CHANCE TO SCATTERED THUNDERSTORM COVERAGE IS
FORECAST THROUGH WEDNESDAY.
A DRY NORTHWEST FLOW WILL DEVELOP FOR THURSDAY AND FRIDAY, AS THE
PLAINS RIDGE BUILDS THROUGH OHIO AND MICHIGAN. FAIR WEATHER AND
MAINLY CLEAR SKIES ARE FORECAST FOR NY/PA.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
12Z SUN UPDATE... ONGOING FOG AT KELM SHOULD BURN OFF BY ARND 14Z.
OTHWS...VFR WILL CONTINUE TO PREVAIL.
WE MAY SEE A FEW SHWRS IN THE VICINITY OF KRME/KSYR TWDS 10-12Z
MON...BUT PROBABILITIES DON`T SEEM HIGH ENUF TO MAKE MENTION OF
THIS IN THE TERMINALS ATTM.
OUTLOOK...
MON THROUGH WED...ALTHOUGH VFR CONDS ARE PROBABLE THE MAJORITY OF
THE TIME...PERIODIC SHWRS/TSTMS ARE PSBL (MOST LIKELY DURG THE
AFTN/EVE HRS). ANY SUCH SHWR/TSTM COULD BRIEFLY PRODUCE
RESTRICTIVE CONDS.
BY THU...GENERALLY VFR CONDS ARE EXPECTED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...
LONG TERM...DJP/MLJ
AVIATION...KAH/MLJ
AREA FORECAST DISCUSSION
NWS BISMARCK ND
949 PM CDT MON AUG 26 2013
.UPDATE...
ISSUED AT 946 PM CDT MON AUG 26 2013
AS OF 245 UTC...ONE LAST STORM REMAINS ACROSS NORTH CENTRAL NORTH
DAKOTA NEAR MOHALL. OTHERWISE...THUNDERSTORM ACTIVITY HAS QUICKLY
DIMINISHED WITH SUNSET AND THE LACK OF A LOW LEVEL JET. DID ADD
FOG TO MOST OF NORTHWEST AND CENTRAL NORTH DAKOTA GIVEN LIGHT
WINDS AND THE VERY HIGH HUMIDITY LEVELS IN PLACE.
UPDATE ISSUED AT 600 PM CDT MON AUG 26 2013
AS OF 2245 UTC...STRONG TO SEVERE THUNDERSTORMS CONTINUE TO
INTENSIFY ACROSS FAR NORTHEAST MONTANA THROUGH DUNN COUNTY IN
NORTH DAKOTA ALONG A WEAK CONVERGENCE LINE. ML CAPE VALUES NEAR
2500 J/KG ARE ANALYZED ALONG THIS LINE ON THE SPC RAPV2
MESOANALYSIS...WHICH APPEARS TO BE HANDLING THE CURRENT
ENVIRONMENT BETTER THAN THE RAPV1. GIVEN DEEP LAYER SHEAR OF 40
KTS...SUPERCELLS ARE LIKELY. THE PRIMARY THREATS ARE DAMAGING
WINDS WITH DOWNDRAFT CAPE VALUES NEAR 1200 J/KG. GIVEN THE HIGH
FREEZING LEVELS AND PWATS...HAIL SURVIVABILITY IS LIMITED. ALSO
MONITORING LOCATIONS NEAR THE SOUTH DAKOTA BORDER ALONG ANOTHER
CONVERGENCE LINE IN A SIMILIAR ENVIRONMENT...WITH THE LATEST 21
UTC HRRR CONTINUING TO SUGGEST CONTINUED GROWTH OF CONVECTION THAT
HAS BEEN INITIATING OVER THE PAST HOUR FOR THESE AREAS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 324 PM CDT MON AUG 26 2013
MAIN CONCERNS THIS SHORT TERM WILL BE THUNDERSTORMS. BROAD FEATURES
INCLUDE A LARGE AND PERSISTENT RIDGE IN THE UPPER ATMOSPHERE. ON THE
WESTERN SIDE OF THE RIDGE A TROPICAL PLUME IS IDENTIFIED ON THE
WATER VAPOR IMAGE. A WEAK SHORTWAVE NOW MOVING THROUGH NORTHEAST
WYOMING WILL SUPPORT CONVECTION THIS EVENING AND OVERNIGHT. AS THE
SHORT WAVE TROUGH TRANSITS ACROSS THE RIDGE EXPECT AN INCREASE IN
THUNDERSTORMS ...WHICH SO FAR TODAY APPEAR TO BY LIMITED BY THE WARM
MID LEVEL TEMPERATURES. WITH THE ADDED LIFT FROM THE SHORTWAVE
EXPECT THUNDERSTORMS TO BECOME MORE ACTIVE LATE THIS AFTERNOON AND
EVENING...MAINLY SOUTH CENTRAL AND SOUTHEAST. MULTIPLE WEAK OUTFLOW
BOUNDARIES EXIST ACROSS THE SOUTH CENTRAL...AND CLOUDS ACROSS NORTH
DAKOTA SUPPORTING DIFFERENTIAL HEATING AND ENHANCING THE THERMAL
BOUNDARY.
TONIGHT...THUNDERSTORM THREAT WILL MOVE EAST. ENDED THE CHANCE OF
THUNDERSTORMS AFTER 1 AM. SOUTHEAST UPSLOPE FLOW AND WEAK SHORTWAVE
ENERGY IN FLOW ALOFT WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS
SOUTHWEST TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CDT MON AUG 26 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THE OVERALL UPPER LEVEL PATTERN REMAINS NEARLY UNCHANGED WITH A
CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND DETERMINISTIC
MODELS. FINER DETAILS CONTINUE TO COME TO A CONSENSUS AMONG THE
MODELS EARLY IN THE PERIOD...BUT SIGNIFICANT DIFFERENCES STILL EXIST
OVER THE WEEKEND AND EARLY NEXT WEEK. EXCEPT FOR A FEW ADJUSTMENTS
TO BUMP UP POPS WHERE MODELS ARE MORE IN LINE...STILL UTILIZED A
MODEL BLEND SOLUTION FOR POPS DURING MOST OF THE LONG TERM PERIOD.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BETTER THUNDERSTORM CHANCES
APPEAR IN STORE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WHEN A FEW
UPPER LEVEL WAVES MOVE INTO THE NORTHERN PLAINS AND TEMPORARILY
BREAKS DOWN THE UPPER LEVEL RIDGE. DETERMINISTIC MODELS INDICATE
INCREASED WARM ADVECTION WEDNESDAY AFTERNOON AND EVENING AHEAD OF
SURFACE LOW PRESSURE THAT DEVELOPS OVER THE WESTERN DAKOTAS. POPS
ARE GREATEST WEDNESDAY IN THE WEST HALF DURING THE DAY...WITH HIGHER
CHANCE POPS SPREADING EAST WEDNESDAY NIGHT AS THE INCREASED WARM
ADVECTION AND COOLING UPPER LEVEL TEMPERATURES WITH THE SHORTWAVES
SHOULD SUSTAIN CONVECTION AS IT TRANSLATES EAST.
THURSDAY AND THURSDAY NIGHT...THE LAST OF THIS ROUND OF UPPER LEVEL
SHORTWAVE ENERGY IMPULSES IS PROGGED TO MOVE EAST ACROSS THE STATE
THURSDAY BEFORE EXITING THE REGION THURSDAY AFTERNOON/NIGHT. UPPER
LEVEL RIDGING QUICKLY REBOUNDS ON THURSDAY NIGHT.
FRIDAY THROUGH MONDAY...THE MODELS IN GENERAL KEEP THE UPPER LEVEL
RIDGE ESTABLISHED OVER THE CENTRAL US THROUGH THE WEEKEND. THE
MODELS DIFFER AFTER THIS...WITH THE ECMWF KEEPING THE RIDGE IN PLACE
WHILE THE GFS SOLUTION DEPICTS THE RIDGE BROADENING AND MOVING EAST.
THUS WILL CONTINUE WITH A MODEL BLEND HERE WHICH GIVES MAINLY SLIGHT
CHANCE POPS EACH DAY.
TEMPERATURES SHOULD REMAIN ABOVE AVERAGE THROUGH SATURDAY WITH HIGHS
MAINLY 85-90 NORTH TO LOW TO MID 90S SOUTH. THE MODEL BLEND HINTS OF
TEMPERATURES MOVING BACK TOWARDS SEASONABLE SUNDAY/MONDAY WITH HIGHS
75-85 NORTH AND IN THE 80S SOUTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 948 PM CDT MON AUG 26 2013
MVFR TO IFR FOG IS POSSIBLE ACROSS MUCH OF WESTERN AND CENTRAL
NORTH DAKOTA TONIGHT INTO TUESDAY MORNING. THEREAFTER...VFR
CONDITIONS ARE FORECAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
521 PM CDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 520 PM CDT SUN AUG 25 2013
QUICK UPDATE TO INCREASE AND EXPAND POPS ACROSS WESTERN AND
CENTRAL NORTH DAKOTA FOR THE REMAINDER OF THE EVENING AND
OVERNIGHT. SURFACE BASED CONVECTION HAS BEEN INCREASING ACROSS
SOUTHWEST NORTH DAKOTA AND NORTHWEST SOUTH DAKOTA SINCE 2130 UTC
GIVEN THE LOSS OF CAPPING AND INCREASING UPPER LEVEL FORCING WITH
THE SHORTWAVE ENTERING WESTERN NORTH DAKOTA EVIDENT ON THE LATEST
WATER VAPOR IMAGERY. DEEP LAYER SHEAR ON THE ORDER OF 30-35 KTS
SUPPORTS THE POTENTIAL FOR PERHAPS A SUPERCELL OR TWO...WITH ML
CAPE VALUES AROUND 1500 J/KG. WHILE HIGH FREEZING LEVELS LIMIT THE
HAIL THREAT...DOWNDRAFT CAPE VALUES NEAR 1400 J/KG SUGGEST A
DAMAGING WIND THREAT WITH THE STRONGER STORMS. THE 18 UTC NAM AND
20 UTC HRRR ARE HANDLING THE CONVECTION WELL...WITH THE HRRR
SUGGESTING THE CONVECTION WILL PROPAGATE INTO BISMARCK AND MANDAN
LATER TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 317 PM CDT SUN AUG 25 2013
LATE SUNDAY AFTERNOON...SURFACE HIGH PRESSURE WAS ACROSS SOUTHERN
MANITOBA. A WEAK COLD FRONT WAS SLIDING SOUTH ACROSS CENTRAL NORTH
DAKOTA. ON SATELLITE...WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
MOVE THROUGH WYOMING INTO CENTRAL MONTANA. THIS FEATURE IS
SUPPORTING CONVECTION ACROSS EASTERN MONTANA. SOME SHOWERS AND
ISOLATED THUNDERSTORMS SHOULD ENTER WEST CENTRAL AND NORTHWEST NORTH
DAKOTA LATE THIS AFTERNOON AND EVENING. THEN PROGRESSIVELY TRACKED
THE SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS INTO WESTERN NORTH
DAKOTA OVERNIGHT AND INTO CENTRAL NORTH DAKOTA MONDAY. WITH THE
BASIC RIDGE PATTERN IN PLACE OVER THE CENTRAL AND NORTHERN
PLAINS...CONTINUED WARM TEMPERATURES EXPECTED ON MONDAY...HOWEVER
WITH COLD FRONT BRINGING A SLIGHT RELIEF WITH HIGHS IN THE UPPER 80S
NORTH TO LOWER 90S SOUTH ON MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 317 PM CDT SUN AUG 25 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. THAT RETROGRADES FROM THE
MISSOURI VALLEY WEST INTO THE SOUTHERN PLAINS THROUGH THE PERIOD.
NORTH DAKOTA WILL REMAIN NEAR THE APEX OF THE RIDGE THROUGH THE LONG
TERM FORECAST PERIOD...WHICH WILL CONTINUE TO INDICATE ABOVE AVERAGE
DAYTIME HIGH TEMPERATURES. SOUTHERN PORTIONS OF THE CWA COULD FLIRT
WITH HEAT ADVISORY CRITERIA LATER IN THE WEEK. IN ADDITION...ALMOST
DAILY THUNDERSTORM CHANCES CAN BE EXPECTED WITH HIGH CAPES EVERY DAY
BUT A STRONG CAP LIMITING CONVECTION.
THE DETERMINISTIC MODELS CONTINUE TO ADVERTISE A FEW...MORE
SIGNIFICANT...WAVES WORKING THROUGH THE MEAN RIDGE AND BRINGING
BETTER PRECIPITATION CHANCES. ON MONDAY AND INTO MONDAY NIGHT THE
ECMWF/GEM APPEAR STRONGER WITH A WAVE MOVING INTO NORTH DAKOTA AND
BRING QPF ACROSS THE NORTH. THE SOUTH MAY REMAIN CAPPED UNDER WARM
MID LEVEL TEMPERATURES.
WAVES CONTINUE TO WORK THROUGH THE MEAN RIDGE ON WEDNESDAY THROUGH
SATURDAY BUT TIMING AND PLACEMENT DIFFERENCES CONTINUE BETWEEN
MODELS AND MODEL RUNS. THEREFORE WILL CONTINUE TO UTILIZE A BLENDED
SOLUTION FOR PRECIPITATION. THIS WILL MEAN BETTER CHANCES WEDNESDAY
THROUGH THURSDAY AFTERNOON...THEN CHANCES ARE ON AND OFF FRIDAY
NIGHT THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 310 PM CDT SUN AUG 25 2013
AT 3 PM CDT...A COLD FRONT EXTENDED ACROSS CENTRAL NORTH DAKOTA. THE
FRONT IS FORECAST TO SLIDE SOUTH TONIGHT. A SHORTWAVE TROUGH IS
IDENTIFIED ON SATELLITE MOVING INTO EASTERN MONTANA. WIDELY
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE INTO WESTERN
NORTH DAKOTA IMPACTING KISN/KDIK THIS EVENING. HOWEVER...TOO WIDELY
SCATTERED TO MENTION TSRA AT THIS TIME. AS THE SHORTWAVE MOVES
THROUGH WESTERN NORTH DAKOTA TONIGHT AND MONDAY WILL SEE PROGRESSIVE
EASTWARD CHANCE OF THUNDERSTORMS. AGAIN...TO UNCERTAIN AT THIS
TIME...BUT WILL USE VCTS TO INDICATE GENERAL SENSE OF THUNDERSTORMS.
VFR EXPECTED AT ALL TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...JV
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1209 PM CDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 1155 AM CDT SUN AUG 25 2013
AT NOON CDT...A WEAK FRONTAL BOUNDARY ACROSS NORTHERN NORTH DAKOTA
IS FORECAST TO SLIDE SLOWLY SOUTH. LITTLE WEATHER WITH THIS
FEATURE AS IT LIES BENEATH AN H500 RIDGE. WATER VAPOR IMAGERY IS
TRACKING A SHORTWAVE MOVING NORTHEAST UP THE WESTERN PORTION OF
THE RIDGE WHICH SHOULD SUPPORT SOME CONVECTION ACROSS WESTERN NORTH
DAKOTA LATER TONIGHT. FOR THIS UPDATE...REMOVED THE SLIGHT CHANCE
FOR THUNDERSTORMS SOUTHEAST. WILL LEAVE TEMPS/WINDS AS IS.
UPDATE ISSUED AT 1000 AM CDT SUN AUG 25 2013
WEAK HIGH PRESSURE PATTERN OVER THE STATE THIS MORNING WITH A WEAK
TROUGH OF LOW PRESSURE LINGERING ACROSS SOUTH CENTRAL AND
SOUTHEAST NORTH DAKOTA. THIS COULD BE THE FOCUS FOR AN ISOLATED
THUNDERSTORM THIS MORNING. WILL RE EVALUATE THE POTENTIAL FOR THE
AFTERNOON...FOR NOW LEFT A SLIGHT CHANCE THUNDERSTORMS SOUTHEAST
THIS MORNING WHERE HRRR MODEL GENERATES ISOLATED CONVECTION. ARE
OF CLOUDS IN CENTRAL/EASTERN MONTANA APPEAR TO BE ASSOCIATED WITH
A SHORT WAVE CENTERED IN WESTERN WYOMING MOVING NORTHEAST. THE
RIDGE MAY PREVENT THE CLOUDS AND SHOWERS/THUNDERSTORMS FROM MAKING
MUCH EASTWARD ADVANCEMENT INTO WESTERN NORTH DAKOTA THIS
AFTERNOON... ALTHOUGH NEW NAM GENERATES SOME THUNDERSTORMS AFTER 3
PM. DON`T HAVE ENOUGH CONFIDENCE TO MOVE UP THE TIME TABLE FORM
THIS EVENING INTO THE IS AFTERNOON.
UPDATE ISSUED AT 644 AM CDT SUN AUG 25 2013
MAINLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS
MORNING. HIGH PRESSURE OVER THE WEST WITH DRIER AIR WORKING INTO
THE AREA ALLOWED TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE
50S. MEANWHILE A LOW PRESSURE TROUGH REMAINS FROM CENTRAL SOUTH
DAKOTA INTO EAST CENTRAL NORTH DAKOTA WITH MUCH HIGHER HUMIDITIES.
TEMPERATURES HERE HAVE ONLY FALLEN INTO THE UPPER 60S AND LOWER
70S. NO SIGNIFICANT CHANGES TO THE FORECAST THIS UPDATE. DID KEEP
A SLIGHT CHANCE OF THUNDER OVER THE SOUTHEAST NEAR THE WEAK
SURFACE TROUGH. LATEST 06 UTC NAM IS INDICATING LIGHT QPF ENTERING
INTO THE WEST LATER THIS AFTERNOON. WILL LEAVE THIS OUT OF THE
FORECAST FOR NOW BUT WILL LET THE DAY SHIFT MONITOR.
&&
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 303 AM CDT SUN AUG 25
2013
MAIN HIGHLIGHT IN THE SHORT TERM WILL BE ANOTHER HOT DAY WITH
HIGHS WELL INTO THE 90S...HOWEVER THUNDERSTORMS WILL BE CONFINED
TO FAR SOUTH CENTRAL NORTH DAKOTA AND THE SOUTHERN JAMES RIVER
VALLEY.
EARLY THIS MORNING...THE LATEST LOCAL RADAR SHOWS A LINE OF
SHOWERS AND THUNDERSTORMS INITIATING ALONG A FRONTAL BOUNDARY/LOW
CONVERGENCE ZONE...STRETCHING FROM CORSON COUNTY IN SOUTH DAKOTA
NORTHEAST BETWEEN BURLEIGH AND EMMONS COUNTY AND INTO STUTSMAN
COUNTY. WATER VAPOR INDICATIVE OF A SHORTWAVE MOVING THROUGH
CENTRAL NORTH DAKOTA EARLY THIS MORNING PROVIDING THE LIFT NEEDED
TO SUSTAIN AND REDEVELOP THE PRECIPITATION. A COUPLE OF THE
THUNDERSTORMS HAVE COME CLOSE TO SEVERE CRITERIA...AND WILL
CONTINUE TO MONITOR.
FOR TODAY...UPPER LEVEL RIDGING CENTERED OVER CENTRAL KANSAS
COMBINED WITH AN UPPER TROUGH ALONG THE WEST COAST...WILL MAINTAIN
A SOUTHWEST FLOW INTO NORTH DAKOTA. A COUPLE OF SHORTWAVES ARE
FORECAST TO SLIDE ACROSS THE NORTHERN BORDER WITH LITTLE OR NO
AFFECT IN TERMS OF PRECIPITATION. THE AFOREMENTIONED FRONTAL
BOUNDARY IS FORECAST TO SHIFT A BIT FURTHER SOUTH TODAY...INTO
NORTHERN SOUTH DAKOTA. HOWEVER A SHORTWAVE MOVING OUT FROM
COLORADO IS FORECAST TO MOVE INTO CENTRAL SOUTH DAKOTA THIS
AFTERNOON. THIS SHOULD LEAD TO ISOLATED THUNDERSTORMS IN OUR
SOUTHEAST ZONES CLOSEST TO THE FRONT. ELSEWHERE EXPECT MOSTLY
SUNNY...DRY..AND HOT CONDITIONS WITH HIGHS 90F TO 98F. HEAT
INDICES ARE FORECAST IN THE MID TO UPPER 90S IN OUR SOUTH CENTRAL
ZONES AND WILL CONTINUE TO MENTION THIS IN THE HAZARDOUS WEATHER
OUTLOOK.
FOR SUNDAY NIGHT...LEE SIDE TROUGH DEVELOPS IN SOUTHEAST MONTANA
AS A COUPLE OF SHORTWAVES ARRIVE VIA THE SOUTHWEST FLOW INTO
WESTERN NORTH DAKOTA. HAVE MENTIONED ISOLATED THUNDERSTORMS WEST
SUNDAY NIGHT WITH DRY CONDITIONS CENTRAL. LOWS WILL AGAIN BE IN
THE 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 303 AM CDT SUN AUG 25 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. THAT RETROGRADES FROM THE
MISSOURI VALLEY WEST INTO THE SOUTHERN PLAINS THROUGH THE PERIOD.
NORTH DAKOTA WILL REMAIN NEAR THE APEX OF THE RIDGE THROUGH THE
WHICH WILL CONTINUE TO INDICATE VERY WARM DAYTIME HIGH TEMPERATURES.
SOUTHERN PORTIONS OF THE CWA COULD FLIRT WITH HEAT ADVISORY
CRITERIA ON MONDAY AND AGAIN LATER IN THE WEEK. IN ADDITION...
ALMOST DAILY THUNDERSTORM CHANCES CAN BE EXPECTED WITH HIGH CAPES
EVERY DAY BUT A STRONG CAP LIMITING CONVECTION.
THE DETERMINISTIC MODELS CONTINUE TO ADVERTISE A FEW...MORE
SIGNIFICANT...WAVES WORKING THROUGH THE MEAN RIDGE AND BRINGING
BETTER PRECIPITATION CHANCES. ON MONDAY THE ECMWF/GEM APPEAR
STRONGER WITH A WAVE MOVING INTO NORTH DAKOTA AND BRING QPF ACROSS
THE NORTH. THE SOUTH WILL LIKELY REMAIN CAPPED UNDER WARM MID
LEVEL TEMPERATURES. THE GFS IS STRONGER WITH THE RIDGING OVER THE
AREA AND KEEPS PRECIPITATION MAINLY NORTH OF THE BORDER.
WAVES CONTINUE TO WORK THROUGH THE MEAN RIDGE ON WEDNESDAY THROUGH
FRIDAY BUT TIMING AND PLACEMENT DIFFERENCES INCREASE WITH LESS
CONSENSUS BETWEEN THE MODELS EXISTS THAN THE MODEL RUNS FROM 24
HOURS AGO. THEREFORE WILL CONTINUE TO UTILIZE A BLENDED SOLUTION
FOR PRECIPITATION. MODELS DO INDICATE AT LEAST A TEMPORARY
BREAKDOWN OF THE UPPER RIDGE LATE IN THE PERIOD WITH THE ECMWF A
GOOD 18 TO 24 HOURS QUICKER TO BRING PRECIPITATION CHANCES AND
COOLER TEMPERATURES TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1155 AM CDT SUN AUG 25 2013
AT NOON CDT...A REGION OF HIGH PRESSURE ACROSS SOUTHERN CANADA AND
NORTHERN NORTH DAKOTA WILL BRING VFR CONDITIONS TO THE REGION
THROUGH THE 18Z TAF PERIOD. A WEAK FRONTAL BOUNDARY WILL MOVE TO
SOUTHEAST MONTANA AND SOUTHERN NORTH DAKOTA SUNDAY NIGHT. A
SHORTWAVE TROUGH ACROSS WYOMING INTO SOUTHERN MONTANA WILL BE THE
FEATURES THAT FOCUS SCATTERED THUNDERSTORMS ACROSS WESTERN NORTH
DAKOTA LATE TONIGHT INTO MONDAY MORNING WEST. THIS WILL IMPACT
KDIK-KBIS-KMOT-KISN AFTER 06Z. WILL HANDLE WITH VCTS AS THREAT
FAIRLY ISOLATED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1001 AM CDT SUN AUG 25 2013
.UPDATE...
ISSUED AT 1000 AM CDT SUN AUG 25 2013
WEAK HIGH PRESSURE PATTERN OVER THE STATE THIS MORNING WITH A WEAK
TROUGH OF LOW PRESSURE LINGERING ACROSS SOUTH CENTRAL AND
SOUTHEAST NORTH DAKOTA. THIS COULD BE THE FOCUS FOR AN ISOLATED
THUNDERSTORM THIS MORNING. WILL RE EVALUATE THE POTENTIAL FOR THE
AFTERNOON...FOR NOW LEFT A SLIGHT CHANCE THUNDERSTORMS SOUTHEAST
THIS MORNING WHERE HRRR MODEL GENERATES ISOLATED CONVECTION. ARE
OF CLOUDS IN CENTRAL/EASTERN MONTANA APPEAR TO BE ASSOCIATED WITH
A SHORT WAVE CENTERED IN WESTERN WYOMING MOVING NORTHEAST. THE
RIDGE MAY PREVENT THE CLOUDS AND SHOWERS/THUNDERSTORMS FROM MAKING
MUCH EASTWARD ADVANCEMENT INTO WESTERN NORTH DAKOTA THIS
AFTERNOON... ALTHOUGH NEW NAM GENERATES SOME THUNDERSTORMS AFTER 3
PM. DON`T HAVE ENOUGH CONFIDENCE TO MOVE UP THE TIME TABLE FORM
THIS EVENING INTO THE IS AFTERNOON.
UPDATE ISSUED AT 644 AM CDT SUN AUG 25 2013
MAINLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA THIS
MORNING. HIGH PRESSURE OVER THE WEST WITH DRIER AIR WORKING INTO
THE AREA ALLOWED TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE
50S. MEANWHILE A LOW PRESSURE TROUGH REMAINS FROM CENTRAL SOUTH
DAKOTA INTO EAST CENTRAL NORTH DAKOTA WITH MUCH HIGHER HUMIDITIES.
TEMPERATURES HERE HAVE ONLY FALLEN INTO THE UPPER 60S AND LOWER
70S. NO SIGNIFICANT CHANGES TO THE FORECAST THIS UPDATE. DID KEEP
A SLIGHT CHANCE OF THUNDER OVER THE SOUTHEAST NEAR THE WEAK
SURFACE TROUGH. LATEST 06 UTC NAM IS INDICATING LIGHT QPF ENTERING
INTO THE WEST LATER THIS AFTERNOON. WILL LEAVE THIS OUT OF THE
FORECAST FOR NOW BUT WILL LET THE DAY SHIFT MONITOR.
&&
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 303 AM CDT SUN AUG 25
2013
MAIN HIGHLIGHT IN THE SHORT TERM WILL BE ANOTHER HOT DAY WITH
HIGHS WELL INTO THE 90S...HOWEVER THUNDERSTORMS WILL BE CONFINED
TO FAR SOUTH CENTRAL NORTH DAKOTA AND THE SOUTHERN JAMES RIVER
VALLEY.
EARLY THIS MORNING...THE LATEST LOCAL RADAR SHOWS A LINE OF
SHOWERS AND THUNDERSTORMS INITIATING ALONG A FRONTAL BOUNDARY/LOW
CONVERGENCE ZONE...STRETCHING FROM CORSON COUNTY IN SOUTH DAKOTA
NORTHEAST BETWEEN BURLEIGH AND EMMONS COUNTY AND INTO STUTSMAN
COUNTY. WATER VAPOR INDICATIVE OF A SHORTWAVE MOVING THROUGH
CENTRAL NORTH DAKOTA EARLY THIS MORNING PROVIDING THE LIFT NEEDED
TO SUSTAIN AND REDEVELOP THE PRECIPITATION. A COUPLE OF THE
THUNDERSTORMS HAVE COME CLOSE TO SEVERE CRITERIA...AND WILL
CONTINUE TO MONITOR.
FOR TODAY...UPPER LEVEL RIDGING CENTERED OVER CENTRAL KANSAS
COMBINED WITH AN UPPER TROUGH ALONG THE WEST COAST...WILL MAINTAIN
A SOUTHWEST FLOW INTO NORTH DAKOTA. A COUPLE OF SHORTWAVES ARE
FORECAST TO SLIDE ACROSS THE NORTHERN BORDER WITH LITTLE OR NO
AFFECT IN TERMS OF PRECIPITATION. THE AFOREMENTIONED FRONTAL
BOUNDARY IS FORECAST TO SHIFT A BIT FURTHER SOUTH TODAY...INTO
NORTHERN SOUTH DAKOTA. HOWEVER A SHORTWAVE MOVING OUT FROM
COLORADO IS FORECAST TO MOVE INTO CENTRAL SOUTH DAKOTA THIS
AFTERNOON. THIS SHOULD LEAD TO ISOLATED THUNDERSTORMS IN OUR
SOUTHEAST ZONES CLOSEST TO THE FRONT. ELSEWHERE EXPECT MOSTLY
SUNNY...DRY..AND HOT CONDITIONS WITH HIGHS 90F TO 98F. HEAT
INDICES ARE FORECAST IN THE MID TO UPPER 90S IN OUR SOUTH CENTRAL
ZONES AND WILL CONTINUE TO MENTION THIS IN THE HAZARDOUS WEATHER
OUTLOOK.
FOR SUNDAY NIGHT...LEE SIDE TROUGH DEVELOPS IN SOUTHEAST MONTANA
AS A COUPLE OF SHORTWAVES ARRIVE VIA THE SOUTHWEST FLOW INTO
WESTERN NORTH DAKOTA. HAVE MENTIONED ISOLATED THUNDERSTORMS WEST
SUNDAY NIGHT WITH DRY CONDITIONS CENTRAL. LOWS WILL AGAIN BE IN
THE 60S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 303 AM CDT SUN AUG 25 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. THAT RETROGRADES FROM THE
MISSOURI VALLEY WEST INTO THE SOUTHERN PLAINS THROUGH THE PERIOD.
NORTH DAKOTA WILL REMAIN NEAR THE APEX OF THE RIDGE THROUGH THE
WHICH WILL CONTINUE TO INDICATE VERY WARM DAYTIME HIGH TEMPERATURES.
SOUTHERN PORTIONS OF THE CWA COULD FLIRT WITH HEAT ADVISORY
CRITERIA ON MONDAY AND AGAIN LATER IN THE WEEK. IN ADDITION...
ALMOST DAILY THUNDERSTORM CHANCES CAN BE EXPECTED WITH HIGH CAPES
EVERY DAY BUT A STRONG CAP LIMITING CONVECTION.
THE DETERMINISTIC MODELS CONTINUE TO ADVERTISE A FEW...MORE
SIGNIFICANT...WAVES WORKING THROUGH THE MEAN RIDGE AND BRINGING
BETTER PRECIPITATION CHANCES. ON MONDAY THE ECMWF/GEM APPEAR
STRONGER WITH A WAVE MOVING INTO NORTH DAKOTA AND BRING QPF ACROSS
THE NORTH. THE SOUTH WILL LIKELY REMAIN CAPPED UNDER WARM MID
LEVEL TEMPERATURES. THE GFS IS STRONGER WITH THE RIDGING OVER THE
AREA AND KEEPS PRECIPITATION MAINLY NORTH OF THE BORDER.
WAVES CONTINUE TO WORK THROUGH THE MEAN RIDGE ON WEDNESDAY THROUGH
FRIDAY BUT TIMING AND PLACEMENT DIFFERENCES INCREASE WITH LESS
CONSENSUS BETWEEN THE MODELS EXISTS THAN THE MODEL RUNS FROM 24
HOURS AGO. THEREFORE WILL CONTINUE TO UTILIZE A BLENDED SOLUTION
FOR PRECIPITATION. MODELS DO INDICATE AT LEAST A TEMPORARY
BREAKDOWN OF THE UPPER RIDGE LATE IN THE PERIOD WITH THE ECMWF A
GOOD 18 TO 24 HOURS QUICKER TO BRING PRECIPITATION CHANCES AND
COOLER TEMPERATURES TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 1000 AM CDT SUN AUG 25 2013
AT 9 AM CDT...WEAK REGION OF HIGH PRESSURE COVERED NORTH DAKOTA.
SKIES WERE CLEAR AND VFR CONDITIONS PREVAILED. LITTLE WILL CHANGE
TODAY AS VFR IS EXPECTED TO CONTINUE. SCATTERED SHOWERS AND
THUNDERSTORMS ARE FORECAST TO MOVE INTO WESTERN NORTH DAKOTA LATE
THIS EVENING AND OVERNIGHT. SOME THUNDERSTORMS MAY IMPACT KISN-
KDIK AFTER 08Z/3 AM USING THE VCTS TO DESCRIBE THE THREAT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS TULSA OK
1211 PM CDT SUN AUG 25 2013
.DISCUSSION...
THE 18Z TAF DISCUSSION IS INCLUDED BELOW.
&&
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL BENEATH A MID AND UPPER LEVEL RIDGE OF
HIGH PRESSURE. THE ONLY EXCEPTION WILL BE SOME LIGHT MVFR FOG AT
KBVO...KRVS AND THE W/NW AR TAF SITES AROUND 12Z IN THE MORNING.
SHRA/TSRA CHANCES ARE TOO LOW TO MENTION IN THE TAFS.
LACY
&&
.PREV DISCUSSION... /ISSUED 904 AM CDT SUN AUG 25 2013/
DISCUSSION...
ANOTHER HOT AND HUMID DAY IS IN STORE FOR EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS WITH MID/UPPER RIDGING IN CONTROL. 12Z UPPER
AIR DATA INDICATES 500MB HEIGHTS ARE RISING AND SOME 700MB
MOISTURE REMAINS AT LITTLE ROCK...SHREVEPORT AND FORT WORTH. THIS
WOULD SUGGEST THE BEST POTENTIAL FOR ISOLATED AFTERNOON
SHOWERS/STORMS WILL BE OVER THE HIGH TERRAIN OF SOUTHEAST OKLAHOMA
AND/OR WEST CENTRAL ARKANSAS AND DOWN NEAR THE RED RIVER. COVERAGE
OF PRECIP YESTERDAY WAS VERY LOW...AND WITH THE RISING UPPER
HEIGHTS THAT WILL LIKELY NOT CHANGE TODAY. THE LATEST HRRR SHOWS
HINTS OF ISOLATED DEVELOPMENT DOWN IN THAT REGION. WILL ELECT TO
CARRY SILENT 10 POPS THERE...AND WILL MONITOR THE CU FIELD LATER
TODAY TO SEE IF AN INCREASE IS WARRANTED IN SPOTS.
LACY
PREV DISCUSSION... /ISSUED 320 AM CDT SUN AUG 25 2013/
DISCUSSION...
A LARGE UPPER RIDGE WILL REMAIN PARKED OVER THE AREA THROUGH THE
ENTIRE FORECAST PERIOD. THE GFS IS QUICKER THAN THE ECMWF TO BEGIN
TO BREAK DOWN THE RIDGE NEXT WEEKEND INTO THE FIRST WEEK OF
SEPTEMBER WHICH IS A REVERSAL FROM MODEL RUNS A COUPLE DAYS AGO.
IN THE MEANTIME...HOT WEATHER WITH VERY LITTLE CHANCE OF RAIN WILL
PREVAIL. TEMPERATURES WILL SLOWLY INCH UP LATER THIS WEEK...LIKELY
PEAKING ON FRIDAY OR SATURDAY. STAYED CLOSE TO GUIDANCE
TEMPERATURES THE NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 94 74 94 74 / 0 0 0 0
FSM 94 73 94 73 / 10 0 0 0
MLC 94 73 95 73 / 10 10 10 0
BVO 94 69 94 69 / 0 0 0 0
FYV 91 67 90 67 / 10 0 0 0
BYV 91 69 90 69 / 0 0 0 0
MKO 94 71 93 71 / 0 0 0 0
MIO 91 71 93 71 / 0 0 0 0
F10 94 73 93 73 / 0 0 0 0
HHW 96 72 96 72 / 10 10 10 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...30
AREA FORECAST DISCUSSION
NWS TULSA OK
904 AM CDT SUN AUG 25 2013
.DISCUSSION...
ANOTHER HOT AND HUMID DAY IS IN STORE FOR EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS WITH MID/UPPER RIDGING IN CONTROL. 12Z UPPER
AIR DATA INDICATES 500MB HEIGHTS ARE RISING AND SOME 700MB
MOISTURE REMAINS AT LITTLE ROCK...SHREVEPORT AND FORT WORTH. THIS
WOULD SUGGEST THE BEST POTENTIAL FOR ISOLATED AFTERNOON
SHOWERS/STORMS WILL BE OVER THE HIGH TERRAIN OF SOUTHEAST OKLAHOMA
AND/OR WEST CENTRAL ARKANSAS AND DOWN NEAR THE RED RIVER. COVERAGE
OF PRECIP YESTERDAY WAS VERY LOW...AND WITH THE RISING UPPER
HEIGHTS THAT WILL LIKELY NOT CHANGE TODAY. THE LATEST HRRR SHOWS
HINTS OF ISOLATED DEVELOPMENT DOWN IN THAT REGION. WILL ELECT TO
CARRY SILENT 10 POPS THERE...AND WILL MONITOR THE CU FIELD LATER
TODAY TO SEE IF AN INCREASE IS WARRANTED IN SPOTS.
LACY
&&
.PREV DISCUSSION... /ISSUED 320 AM CDT SUN AUG 25 2013/
DISCUSSION...
A LARGE UPPER RIDGE WILL REMAIN PARKED OVER THE AREA THROUGH THE
ENTIRE FORECAST PERIOD. THE GFS IS QUICKER THAN THE ECMWF TO BEGIN
TO BREAK DOWN THE RIDGE NEXT WEEKEND INTO THE FIRST WEEK OF
SEPTEMBER WHICH IS A REVERSAL FROM MODEL RUNS A COUPLE DAYS AGO.
IN THE MEANTIME...HOT WEATHER WITH VERY LITTLE CHANCE OF RAIN WILL
PREVAIL. TEMPERATURES WILL SLOWLY INCH UP LATER THIS WEEK...LIKELY
PEAKING ON FRIDAY OR SATURDAY. STAYED CLOSE TO GUIDANCE
TEMPERATURES THE NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 94 74 94 72 / 0 0 0 0
FSM 94 73 94 71 / 10 0 0 0
MLC 94 73 94 71 / 10 10 10 0
BVO 93 69 93 67 / 0 0 0 0
FYV 91 67 91 65 / 10 0 0 0
BYV 91 68 91 66 / 0 0 0 0
MKO 93 72 93 70 / 0 0 0 0
MIO 91 71 91 69 / 0 0 0 0
F10 93 73 93 71 / 0 0 0 0
HHW 96 73 96 71 / 10 10 10 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
419 PM EDT SUN AUG 25 2013
.SYNOPSIS...
DRIER HIGH PRESSURE WILL PERSIST THROUGH MIDWEEK BEFORE AN UPPER
LEVEL DISTURBANCE AND AN ASSOCIATED SURFACE COLD FRONT MOVE THROUGH
THE REGION ON THURSDAY. THIS WILL BRING THE GREATEST CHANCES FOR
SHOWERS AND THUNDERSTORMS FOR THE WEEK. WEAK HIGH PRESSURE WILL
RETURN IN THE FRONTS WAKE FOR THE START OF NEXT WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
4 PM UPDATE...LITTLE CHANGE EXCEPT TO TOUCH UP SKY...TEMPS AND
DEWPTS FROM LATEST OBS. LATEST RAP DOES PRODUCE SOME LIGHT PRECIP
THIS AFTN IN THE SMOKIES BUT SATELLITE TRENDS SUGGEST THE SCATTERED
CLOUD COVER THERE IS TOO SHALLOW FOR PRECIP. WILL HOLD ON TO DRY
FCST.
AS OF 140 PM EDT SUNDAY...THE PATTERN WILL TRANSITION FROM ONE OF
COLD AIR DAMMING...WITH A FAIRLY TIGHT SFC PRESSURE GRADIENT AND
MODERATE LLVL ADVECTION OF DRY AND COOL AIR...TO ONE WITH A BROAD
RIDGE OF HIGH PRESSURE COVERING THE ENTIRE REGION. THIS WILL SHUT
OFF THE COLD ADVECTION...RESULTING IN MODERATING TEMPERATURES AND
NEARLY CALM WINDS TONIGHT AND MONDAY. THE DEWPOINTS SHOULD STILL
REMAIN LOW WITH SUBSIDENCE ACROSS THE SE STATES. THERE WILL BE SOME
UPSLOPE INDUCED STRATO-CU MUCH OF THE NIGHT ALONG THE BLUE RIDGE.
TOMORROW WE SHOULD SEE A WIDESPREAD CU FIELD DEVELOP ACROSS THE
REGION DURING THE LATE MORNING AND AFTERNOON HOURS.
TONIGHT/S FORECAST LOW TEMPERATURE OF 58 DEGREES AT CHARLOTTE...IF
IT VERIFIES...WILL BE THE COOLEST READING SINCE JUNE 15TH. AND WHILE
CHARLOTTE DID SEE A COUPLE READINGS IN THE 50S LAST AUGUST...THEY
HADN/T SEE READINGS IN THE 50S DURING THIS MONTH SINCE 2004 BEFORE
THAT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AT 150 PM EDT SUNDAY...AN UPPER RIDGE WILL BE CENTERED OVER THE
MIDDLE OF THE NATION MONDAY EVENING...WHILE AN UPPER TROUGH AXIS
REMAINS OFF THE EAST COAST. THE UPPER TROUGH AXIS RETROGRESSES
CLOSER TO THE COAST BY WEDNESDAY....SUCH THAT HEIGHTS FALL ALONG HE
EASTERN SEABOARD.
A SHORTWAVE TROUGH WILL DROP INTO THE ATLANTIC TROUGH MONDAY
NIGHT...CROSSING THE NORTHEAST USA. ANOTHER...WEAKER SHORTWAVE WILL
FOLLOW SUIT LATE TUESDAY AND CROSS THE MID ATLANTIC REGION...AND A
THIRD SYSTEM CROSS THE CAROLINAS ON WEDNESDAY.
WEAKENING HIGH PRESSURE WILL BE IN PLACE OVER THE CAROLINAS AND GA
ON MONDAY NIGHT. MODEL TIME HEIGHTS SHOW VERY DRY AIR BETWEEN 850 MB
AND 300 MB...WITH LIMITED LOW LEVEL MOISTURE. ON TUESDAY A SURFACE
TROUGH IS EXPECTED TO FORM IN THE LEE OF THE MOUNTAINS AS THE
SURFACE HIGH MOVES WEST ACROSS THE GULF STATES...WHILE BOTH LOW AND
MID LEVEL MOISTURE INCREASE FROM THE NORTH AHEAD OF A COLD FRONT
APPROACHING THE OH RIVER VALLEY. THE LEE TROUGH PERSISTS INTO
WEDNESDAY...WHILE THE MODELS CONTINUE TO SHOW A RELATIVE DRY
LAYER...ALBEIT SLOWLY MOISTENING...BETWEEN AROUND 600 MB AND 800 MB.
PRECIPITATION IS NOT EXPECTED ON MONDAY NIGHT THROUGH TUESDAY NIGHT
WITH INITIALLY DRY MID LEVELS...AND PRONOUNCED SUBSIDENCE INVERSION.
PRECIPITATION CHANCES INCREASE ON WEDNESDAY WITH INCREASING MOISTURE
AND INSTABILITY...AND COOLING ALOFT...BUT WILL STILL REMAIN IN THE
CHANCE CATEGORY. TEMPERATURES WILL WARM FROM SLIGHTLY BELOW NORMAL
MONDAY NIGHT...TO NEAR NORMAL FROM TUESDAY THROUGH WEDNESDAY...AS
THE AIR MASS MODIFIES...AND HIGH PRESSURE MOVES OFF TO THE
WEST...INTRODUCING A LIGHT WESTERLY DOWNSLOPE FLOW COMPONENT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 130 PM EDT SUNDAY...THE MEDIUM RANGE PICKS UP AT 00Z ON
THURSDAY WITH THE LARGE UPPER RIDGE CENTERED OVER THE CENTRAL CONUS
AND NORTHERN STREAM UPPER TROFFING OVER SOUTHEASTERN CANADA. THE
UPPER RIDGE IS EXPECTED TO REMAIN LARGELY IN PLACE IF NOT SLIDE A
BIT WESTWARD OVER THE NEXT FEW DAYS AND THEN FLATTEN OVER THE
WEEKEND. THIS WILL RESULT IN MINOR HEIGHT FALLS AND A FEW WEAK
SHORTWAVES MOVING OVER THE FCST ARE ON THURS AND FRI. AT THE SFC...A
TRAILING COLD FRONT WILL MOVE INTO THE CWFA EARLY IN THE DAY AND
BRING A PLUME OF DEEPER MOISTURE WITH IT. MODELS INDICATE THAT THE
FRONT SHOULD BE MOVING OFF THE SE COAST BY LATE THURS/EARLY FRI WITH
ANOTHER CANADIAN SFC HIGH BRINGING WEAK NLY LOW LVL FLOW IN THE
FRONTS WAKE. OVER THE WEEKEND...AS THE HIGH MOVES NE OF THE
REGION...WINDS WILL LIKELY BECOME NEAR CALM AND THEN EVENTUALLY SLY
AS THE BERMUDA HIGH TRIES TO REGAIN ITS INFLUENCE. POPS AND QPF WERE
REDUCED A BIT ON THURS AS THE LATEST MODEL RUNS ARE SUGGESTING A
DRIER OVERALL FROPA. OTHERWISE...I STILL CARRY DIURNAL CHANCE TO
SLIGHT CHANCE POPS FOR FRI AND SLIGHT CHANCE FOR SAT AND SUN. I
BUMPED UP HIGH TEMPS A DEGREE OR 2 FOR THURS AND FRI WITH VALUES NOW
AROUND CLIMO. VALUES WILL LIKELY DROP A FEW DEGREES FOR SAT AND SUN
WITH LOWER THICKNESSES ANTICIPATED.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
AT KCLT /21Z UPDATE/...A DEEP LAYER RIDGE OF HIGH PRESSURE WILL
REMAIN OVER THE REGION THROUGH THE VALID PERIOD OF THE TAF. THE
GRADIENT WILL WEAKEN AS THE CENTER OF THE RIDGE MOVES
OVERHEAD...RESULTING IN A LONG PERIOD OF CALM WINDS TONIGHT AND
MONDAY MORNING. WINDS THIS AFTN SHOULD REMAIN OUT OF THE NE AT
5-8KTS...WITH A FEW GUSTS TO 10-15 KT PER TDWR WINDS JUST OFF THE
SFC. SCT TO BKN CU IN THE 4-6KFT RANGE SHOULD PERSIST UNTIL AROUND 6
PM AT WHICH TIME THEY SHOULD DISSIPATE.
ELSEWHERE...THE WEATHER PATTERN IS THE SAME AS AT KCLT WITH SIMILAR
CONDITIONS AT THE OTHER AIRFIELDS. ONE POSSIBLE EXCEPTION IS AT
KAVL. THEY SHOULD FALL UNDER THEIR CROSSOVER TEMPERATURE LATER
TONIGHT. CERTAINLY PARTS OF THE FRENCH BROAD VALLEY WILL SEE
FOG...BUT IT/S NEVER AN EASY CALL AT KAVL. I LIKED THE MID SHIFT/S
2SM AND SCT005 SO I RETAINED THAT IN THE FORECAST.
OUTLOOK...A DRY PATTERN IS EXPECTED THROUGH TUESDAY AS HIGH PRESSURE
BUILDS IN FROM THE NORTH AND PERSISTS. MOISTURE WILL START TO RETURN
AHEAD OF A FRONT APPROACHING FROM THE NW DURING MID AND LATE WEEK.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% LOW 56% HIGH 86%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...MCAVOY/WIMBERLEY
SHORT TERM...JAT
LONG TERM...JPT
AVIATION...MCAVOY/WIMBERLEY
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
814 PM CDT MON AUG 26 2013
.UPDATE...
NO MAJOR UPDATES THIS EVENING. STORMS STILL POSSIBLE ACROSS THE
FAR NORTHERN CWA OVERNIGHT. TEMPERATURES LOOK FINE.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH THURSDAY MORNING
CURRENT SURFACE ANALYSIS SHOWS A WEAK SURFACE LOW CENTERED OVER
THE KPIR AREA...WITH A WARM FRONT EXTENDING THROUGH KABR AND
K8D3 AND INTO WEST CENTRAL MINNESOTA. MODELS ARE SHOWING AN
ELONGATED AREA OF SHEARED OUT VORTICITY WORKING ITS WAY UP AND
OVER THE RIDGE. AREAS SOUTH OF THE WARM FRONT WILL LIKELY BE TOO
CAPPED FOR ANY CONVECTION TO DEVELOP /THE 700 MB TEMPERATURE OFF
THE MORNING KABR SOUNDING WAS 14 C/...HOWEVER CHANCES ARE DECENT
NORTH OF THE FRONT. THIS LOOKS LIKE IT WILL BE MAINLY OUR FAR
NORTHERN CWA TONIGHT. WITH OVER 2000 J/KG OF ML CAPE AND 40 TO 50
KTS OF 0-6 KM SHEAR PRESENT THIS EVENING...THERE IS CERTAINLY THE
CHANCE FOR ISOLATED SEVERE STORMS ALONG OUR NORTH. THE MOST RECENT
RUNS OF THE HRRR MODEL SEEM TO BE HANDLING THE SCENARIO
WELL...DEVELOPING STORMS ACROSS THE FAR NORTHWEST LATER THIS
AFTERNOON...AND THEN TRACKING ADDITIONAL ISOLATED SUPERCELLS ALONG
THE ND/SD BORDER BEFORE DROPPING THE CONVECTION INTO OUR FAR
NORTHEAST CWA LATER TONIGHT.
HOT TEMPERATURES CONTINUE TO AFFECT THE REGION THROUGH THE
REMAINDER OF THE SHORT TERM. MODEL 850 MB TEMPERATURES DO COOL
SLIGHTLY TUESDAY...WITH PERHAPS SOME DRIER AIR TRYING TO WORK INTO
THE REGION TUESDAY AND WEDNESDAY. HOWEVER...WITH MORE OF A NORTH
TO NORTHEAST SURFACE FLOW ON TUESDAY AND THEN WINDS SWITCHING BACK
TO THE SOUTHEAST ON WEDNESDAY...VERY SKEPTICAL ON DEWPOINTS DROPPING
MUCH LOWER THAN THE LOW TO MID 60S. HEAT INDICES DO APPEAR TO
REMAIN BELOW THE 100 DEGREE MARK HOWEVER. AS THE UPPER HIGH
WOBBLES AROUND THE CENTRAL PLAINS ADDITIONAL SHORTWAVE ENERGY IS
PROGGED TO MOVE ACROSS THE NORTHERN PLAINS. MODELS HAVE BEEN
FAIRLY CONSISTENT WITH THUNDERSTORM CHANCES ACROSS OUR WEST
TUESDAY NIGHT...AND THEN ACROSS OUR NORTH AND EAST ON WEDNESDAY
NIGHT AND THURSDAY MORNING. A 20 TO 30 KT LLJ IS ALSO PROGGED TO
SET UP ON WEDNESDAY NIGHT AND THURSDAY MORNING...ALTHOUGH AT THIS
POINT THE NOSE OF THE LLJ LOOKS TO BE PUSHING MORE INTO NORTH
DAKOTA...SO BETTER CHANCES STILL SEEM TO BE NORTH OF OUR CWA. WITH
ANY STORMS THAT CAN DEVELOP OVER THE NEXT COUPLE OF DAYS...ISOLATED
SEVERE STORMS ARE CERTAINLY POSSIBLE.
.LONG TERM...THURSDAY THROUGH MONDAY
THE UPPER RIDGE CONTINUES TO DOMINATE THE PATTERN AT THE START OF
THE EXTENDED. SAT/SUN THERE IS A SLIGHT FLATTENING OF THE RIDGE
SHOWN ON BOTH THE ECMWF AND THE GFS. HOWEVER BY MONDAY THE MODELS
DIVERGE WITH PLACEMENT OF THE RIDGE LEAVING FORECASTER CONFIDENCE
LOW OVER THE LABOR DAY WEEKEND.
MAIN CHALLENGE WILL BE DETERMINING TIMING AND PLACEMENT OF ANY WAVES
THAT RIDE OVER THE RIDGE. STUCK CLOSE TO ALLBLEND DUE TO
UNCERTAINTY AND CURRENTLY HAVE SOME POPS MENTIONED FOR THURSDAY
AND THEN AGAIN SAT/SUN. TEMPERATURES WILL BE VERY WARM WITH HIGHS
IN THE 90S AS LONG AS THE RIDGE HOLDS. WHEN IT FLATTENS OR MOVES
EAST...TEMPS SHOULD FALL ACCORDINGLY BACK CLOSER TO NORMAL.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
OTHER THAN SOME LATE NIGHT FOG AT KABR/KATY IT SHOULD BE VFR AT
ALL TAFS OVERNIGHT. THERE IS SOME CHC FOR CONVECTION AT KMBG THIS
EVENING. MOST ACTIVITY SHOULD END BEFORE MIDNIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TDK
SHORT TERM...SERR
LONG TERM...WISE
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
613 PM CDT MON AUG 26 2013
.UPDATE...
AVIATION DISCUSSION HAS BENN UPDATED.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH THURSDAY MORNING
CURRENT SURFACE ANALYSIS SHOWS A WEAK SURFACE LOW CENTERED OVER
THE KPIR AREA...WITH A WARM FRONT EXTENDING THROUGH KABR AND
K8D3 AND INTO WEST CENTRAL MINNESOTA. MODELS ARE SHOWING AN
ELONGATED AREA OF SHEARED OUT VORTICITY WORKING ITS WAY UP AND
OVER THE RIDGE. AREAS SOUTH OF THE WARM FRONT WILL LIKELY BE TOO
CAPPED FOR ANY CONVECTION TO DEVELOP /THE 700 MB TEMPERATURE OFF
THE MORNING KABR SOUNDING WAS 14 C/...HOWEVER CHANCES ARE DECENT
NORTH OF THE FRONT. THIS LOOKS LIKE IT WILL BE MAINLY OUR FAR
NORTHERN CWA TONIGHT. WITH OVER 2000 J/KG OF ML CAPE AND 40 TO 50
KTS OF 0-6 KM SHEAR PRESENT THIS EVENING...THERE IS CERTAINLY THE
CHANCE FOR ISOLATED SEVERE STORMS ALONG OUR NORTH. THE MOST RECENT
RUNS OF THE HRRR MODEL SEEM TO BE HANDLING THE SCENARIO
WELL...DEVELOPING STORMS ACROSS THE FAR NORTHWEST LATER THIS
AFTERNOON...AND THEN TRACKING ADDITIONAL ISOLATED SUPERCELLS ALONG
THE ND/SD BORDER BEFORE DROPPING THE CONVECTION INTO OUR FAR
NORTHEAST CWA LATER TONIGHT.
HOT TEMPERATURES CONTINUE TO AFFECT THE REGION THROUGH THE
REMAINDER OF THE SHORT TERM. MODEL 850 MB TEMPERATURES DO COOL
SLIGHTLY TUESDAY...WITH PERHAPS SOME DRIER AIR TRYING TO WORK INTO
THE REGION TUESDAY AND WEDNESDAY. HOWEVER...WITH MORE OF A NORTH
TO NORTHEAST SURFACE FLOW ON TUESDAY AND THEN WINDS SWITCHING BACK
TO THE SOUTHEAST ON WEDNESDAY...VERY SKEPTICAL ON DEWPOINTS DROPPING
MUCH LOWER THAN THE LOW TO MID 60S. HEAT INDICES DO APPEAR TO
REMAIN BELOW THE 100 DEGREE MARK HOWEVER. AS THE UPPER HIGH
WOBBLES AROUND THE CENTRAL PLAINS ADDITIONAL SHORTWAVE ENERGY IS
PROGGED TO MOVE ACROSS THE NORTHERN PLAINS. MODELS HAVE BEEN
FAIRLY CONSISTENT WITH THUNDERSTORM CHANCES ACROSS OUR WEST
TUESDAY NIGHT...AND THEN ACROSS OUR NORTH AND EAST ON WEDNESDAY
NIGHT AND THURSDAY MORNING. A 20 TO 30 KT LLJ IS ALSO PROGGED TO
SET UP ON WEDNESDAY NIGHT AND THURSDAY MORNING...ALTHOUGH AT THIS
POINT THE NOSE OF THE LLJ LOOKS TO BE PUSHING MORE INTO NORTH
DAKOTA...SO BETTER CHANCES STILL SEEM TO BE NORTH OF OUR CWA. WITH
ANY STORMS THAT CAN DEVELOP OVER THE NEXT COUPLE OF DAYS...ISOLATED
SEVERE STORMS ARE CERTAINLY POSSIBLE.
.LONG TERM...THURSDAY THROUGH MONDAY
THE UPPER RIDGE CONTINUES TO DOMINATE THE PATTERN AT THE START OF
THE EXTENDED. SAT/SUN THERE IS A SLIGHT FLATTENING OF THE RIDGE
SHOWN ON BOTH THE ECMWF AND THE GFS. HOWEVER BY MONDAY THE MODELS
DIVERGE WITH PLACEMENT OF THE RIDGE LEAVING FORECASTER CONFIDENCE
LOW OVER THE LABOR DAY WEEKEND.
MAIN CHALLENGE WILL BE DETERMINING TIMING AND PLACEMENT OF ANY WAVES
THAT RIDE OVER THE RIDGE. STUCK CLOSE TO ALLBLEND DUE TO
UNCERTAINTY AND CURRENTLY HAVE SOME POPS MENTIONED FOR THURSDAY
AND THEN AGAIN SAT/SUN. TEMPERATURES WILL BE VERY WARM WITH HIGHS
IN THE 90S AS LONG AS THE RIDGE HOLDS. WHEN IT FLATTENS OR MOVES
EAST...TEMPS SHOULD FALL ACCORDINGLY BACK CLOSER TO NORMAL.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
OTHER THAN SOME LATE NIGHT FOG AT KABR/KATY IT SHOULD BE VFR AT
ALL TAFS OVERNIGHT. THERE IS SOME CHC FOR CONVECTION AT KMBG THIS
EVENING. MOST ACTIVITY SHOULD END BEFORE MIDNIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BROWN-BUFFALO-
CLARK-CODINGTON-DAY-DEUEL-FAULK-GRANT-HAMLIN-HAND-HUGHES-
HYDE-LYMAN-MARSHALL-ROBERTS-SPINK.
MN...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BIG STONE-TRAVERSE.
&&
$$
UPDATE...TDK
SHORT TERM...SERR
LONG TERM...WISE
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
310 PM CDT SUN AUG 25 2013
.DISCUSSION...
NORTHWEST GULF OF MEXICO DEEP TROPICAL MOISTURE CONTINUES TO
SPREAD SLOWLY WESTWARD INTO THE TEXAS COAST AS UPPER LEVEL
RIDGING STRENGTHENS TO OUR NORTH. AS ANTICIPATED...ACTIVITY
OVER THE GULF WATERS IS WEAKENING/DISSIPATING THIS AFTERNOON
WHILE INLAND`S STRONGEST STORMS REMAIN GENERALLY CONFINED TO
NEAR AND SOUTH OF INTERSTATE 10. PREVIOUS FORECASTS FROM THE
LAST FEW DAYS THAT HAVE BEEN CALLING FOR UP TO AN INCH OR TWO
OF RAIN FROM SUNDAY THROUGH TUESDAY WITH THE GREATEST CONCENTRATION
ACROSS COASTAL COUNTIES AND ESPECIALLY OFFSHORE STILL LOOKS ON
TRACK WITH THE NEXT SET OF STORMS EXPECTED TO DEVELOP LATER THIS
EVENING AND ON THROUGH THE OVERNIGHT HOURS NEAR THE COAST AND JUST
OFFSHORE. ACTIVITY SHOULD WORK ITS WAY INLAND DURING THE DAY
TOMORROW...BUT THE GREATEST RAINFALL TOTALS ARE STILL ANTICIPATED
TO BE NEAR THE COAST AND OFFSHORE. ANOTHER NOT SO HOT LATE AUGUST
DAY IS EXPECTED UNDER ABUNDANT CLOUD COVER ON MONDAY. TUESDAY
SHOULD BE OUR LAST CHANCE OF RAIN FOR THE WEEK AS THIS SYSTEM
WORKS ITS WAY TO OUR WEST AND NORTHWEST AND UPPER LEVEL RIDGING
AND ASSOCIATED SUBSIDENCE BUILDS ACROSS SOUTHEAST TEXAS. THIS
PATTERN CHANGE TRANSLATES TO BACK TO NEAR NORMAL LATE AUGUST
TEMPERATURES FOR THE ENTIRE AREA. 42
&&
.MARINE...
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING ALMOST ALL
DAY TODAY OVER THE WATERS. THIS IS IN RESPONSE TO A WEAK TROPICAL
WAVE WITH ITS AXIS LOCATED JUST SOUTH OF THE LAKE CHARLES AREA.
WINDS HAVE BEEN AROUND SCEC CRITERIA FOR THE NEARSHORE WATERS WHILE
BELOW CRITERIA PAST 20 NM. THE WAVE AXIS WILL CONTINUE TO NUDGE
WESTWARD TONIGHT AS A SHORTWAVE AT 500 MB APPROACHES. SHOWERS AND
THUNDERSTORMS WILL BE LIKELY MONDAY AND THEN BEGIN TO WANE EARLY
TUESDAY AS THE WAVE AXIS MOVES AWAY. 23
&&
.PREV DISCUSSION... /ISSUED 1251 PM CDT SUN AUG 25 2013/
DISCUSSION...
SEE AVIATION FOR 18Z TAF ISSUANCE.
AVIATION...
OVERVIEW...RAIN CONFINED TO THE COAST TODAY WITH MVFR DECKS ACROSS
MOST OF SOUTHEAST TEXAS. ANOTHER BAND OF RAIN HAS DEVELOPED ALONG
SOUTHERN LAKE CHARLES CWA BORDER AND IS MOVING TOWARDS THE WEST. A
VORTICITY MAXIMUM ASSOCIATED WITH A SHORTWAVE WILL APPROACH THE
COAST MONDAY. GFS/ NAM/ ECMWF HAVE THE FEATURE MOVING INLAND A
TAD BEFORE 11Z WITH THE RAP BEING THE MOST PROGRESSIVE BRINGING
THE SHORTWAVE IN AROUND 3Z MONDAY.
KCLL/KUTS/KCXO...RAIN SHOULD FOR THE MOST PART REMAIN SOUTH OF
THESE TAF SITES WITH MOSTLY BROKEN MVFR CLOUDS. LOOKS LIKE BULK OF
RAIN MONDAY WILL ALSO BE SOUTH OF THESE TAF SITES. A SLIGHT
DEVIATION IN THE TRACK OF THE SHORTWAVE COULD ALTER THE QPF FIELD
THOUGH. WILL HAVE TO CLOSELY MONITOR SITUATION AND ADJUST
ACCORDINGLY.
KIAH/KHOU...CHANCE FOR SCATTERED SHOWERS TO AFFECT THE TERMINALS
THIS AFTERNOON AS REDEVELOPMENT IS ALREADY OCCURRING OFF TO THE
EAST. MOSTLY LIKELY THESE SITES WILL REMAIN IN MVFR CIGS FOR MOST
OF TODAY. THERE MIGHT BE A SLIGHT BREAK THIS EVENING INTO EARLY
MORNING BEFORE THE NEXT ROUND OF CONVECTION APPROACHES. TIMING OF
THE SHORTWAVE IS AGAIN CRUCIAL HERE AS A SLIGHTLY MORE PROGRESSIVE
MOVING SHORTWAVE WOULD FAVOR RAIN STARTING AROUND 6Z WITH THE
GLOBAL MODELS BEING MUCH SLOWER WITH THE TIMING OF THE RAINFALL.
KLBX/KSGR/KGLS...PRECIP IN ONGOING AT KGLS WITH PRECIP LIKELY AT
KLBX AND KSGR. THESE SITES WILL BE THE FIRST LOCATIONS TO SEE THE
RAINFALL MONDAY MORNING ALSO AS THE SHORTWAVE MOVES IN FROM THE
EAST.
23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 74 96 75 / 20 30 10 20 10
HOUSTON (IAH) 75 90 75 95 75 / 30 40 20 30 10
GALVESTON (GLS) 79 88 80 91 81 / 60 60 30 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 10 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...42
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1251 PM CDT SUN AUG 25 2013
.DISCUSSION...
SEE AVIATION FOR 18Z TAF ISSUANCE.
&&
.AVIATION...
OVERVIEW...RAIN CONFINED TO THE COAST TODAY WITH MVFR DECKS ACROSS
MOST OF SOUTHEAST TEXAS. ANOTHER BAND OF RAIN HAS DEVELOPED ALONG
SOUTHERN LAKE CHARLES CWA BORDER AND IS MOVING TOWARDS THE WEST. A
VORTICITY MAXIMUM ASSOCIATED WITH A SHORTWAVE WILL APPROACH THE
COAST MONDAY. GFS/ NAM/ ECMWF HAVE THE FEATURE MOVING INLAND A
TAD BEFORE 11Z WITH THE RAP BEING THE MOST PROGRESSIVE BRINGING
THE SHORTWAVE IN AROUND 3Z MONDAY.
KCLL/KUTS/KCXO...RAIN SHOULD FOR THE MOST PART REMAIN SOUTH OF
THESE TAF SITES WITH MOSTLY BROKEN MVFR CLOUDS. LOOKS LIKE BULK OF
RAIN MONDAY WILL ALSO BE SOUTH OF THESE TAF SITES. A SLIGHT
DEVIATION IN THE TRACK OF THE SHORTWAVE COULD ALTER THE QPF FIELD
THOUGH. WILL HAVE TO CLOSELY MONITOR SITUATION AND ADJUST
ACCORDINGLY.
KIAH/KHOU...CHANCE FOR SCATTERED SHOWERS TO AFFECT THE TERMINALS
THIS AFTERNOON AS REDEVELOPMENT IS ALREADY OCCURRING OFF TO THE
EAST. MOSTLY LIKELY THESE SITES WILL REMAIN IN MVFR CIGS FOR MOST
OF TODAY. THERE MIGHT BE A SLIGHT BREAK THIS EVENING INTO EARLY
MORNING BEFORE THE NEXT ROUND OF CONVECTION APPROACHES. TIMING OF
THE SHORTWAVE IS AGAIN CRUCIAL HERE AS A SLIGHTLY MORE PROGRESSIVE
MOVING SHORTWAVE WOULD FAVOR RAIN STARTING AROUND 6Z WITH THE
GLOBAL MODELS BEING MUCH SLOWER WITH THE TIMING OF THE RAINFALL.
KLBX/KSGR/KGLS...PRECIP IN ONGOING AT KGLS WITH PRECIP LIKELY AT
KLBX AND KSGR. THESE SITES WILL BE THE FIRST LOCATIONS TO SEE THE
RAINFALL MONDAY MORNING ALSO AS THE SHORTWAVE MOVES IN FROM THE
EAST.
23
&&
.PREV DISCUSSION... /ISSUED 1029 AM CDT SUN AUG 25 2013/
DISCUSSION...
DEEP MOISTURE CONTINUES TO SLOWLY FILTER INTO SOUTHEAST TEXAS
FROM THE EAST THIS MORNING IN ASSOCIATION WITH A NORTHWESTERN
GULF OF MEXICO DISTURBANCE. PER WATER VAPOR SATELLITE LOOP...
A MUCH DRIER AIR MASS IS MOVING INTO THE NORTHERN PORTIONS OF
OUR AREA...AND THIS IS EXPECTED TO KEEP THE MAJORITY OF SPOTS
GENERALLY ALONG AND NORTH OF INTERSTATE ON THE DRY SIDE TODAY.
RECENT RADAR TRENDS HAVE ACTIVITY WEAKENING NEAR THE COAST AND
OFFSHORE...SO HAVE MADE SOME DOWNWARD POP ADJUSTMENTS TO AREA
FORECASTS FOR THE REST OF THE DAY. ALSO...SHAVED OFF SEVERAL
DEGREES FROM THIS AFTERNOON`S HIGH TEMPERATURES BASED ON THE
ANTICIPATED EXTRA CLOUD COVER. 42
PREV DISCUSSION... /ISSUED 419 AM CDT SUN AUG 25 2013/
DISCUSSION...
ONGOING FCST HAS BEEN LEFT LARGELY UNCHANGED. DEEPER MOISTURE IS
MOVING INTO THE UPPER TEXAS COASTAL WATERS AND COUNTIES FROM THE
EAST. EXPECT PERIODS OF SHRA/TSRA ACROSS THE SRN PARTS OF THE
REGION THRU THE DAY WITH BEST COVERAGE SOUTH OF I-10. DID KNOCK
POPS DOWN ACROSS FAR NORTHERN COUNTIES WHERE COMPETITION FROM
UPPER RIDGE IS MORE PRONOUNCED. WE`LL PROBABLY SEE A BREAK IN MOST
PRECIP LATE IN THE AFTN AND EARLY THIS EVENING FOLLOWED BY
WIDESPREAD REDEVELOPMENT OFFSHORE AND ALONG THE COAST TONIGHT AND
MON MORNING. COVERAGE WILL THEN GRADUALLY EXPAND INLAND INTO THE
SW HALF OF THE REGION DURING THE DAY. EXPECTING THE BEST COVERAGE
IN THE COUNTIES SW/W OF THE METRO AREA (THAT NEED THE RAINFALL THE
MOST).
CHANCES OF RAINFALL WILL DIMINISH ON TUE/WED AS MOISTURE AXIS
GRADUALLY PUSHES OUT OF THE REGION. BY LATE WED & THURS RAIN
CHANCES WILL BE CLOSE TO NIL AS PW`S DROP AND UPPER RIDGE REALLY
REESTABLISHES ITSELF OVERHEAD. TEMPS SHOULD CLIMB BACK INTO THE
UPPER 90S TO NEAR 100 AT SOME LOCATIONS DURING THE 2ND HALF OF THE
WEEK. 47
TROPICS...
NHC IS WATCHING THE WAVE OFF THE YUCATAN COAST AND CURRENTLY
GIVING IT A 60% CHANCE OF DEVELOPMENT. THIS SYSTEM WILL MOST
LIKELY NOT AFFECT SE TX WX AND PROBABLY BE A MEXICO ISSUE. 47
MARINE...
CONVECTION SLATED TO INCREASE/MOVE INTO THE AREA TODAY AS THE WEAK
TROPICAL WAVE EDGES CLOSER. THIS SYSTEM WILL ALSO HELP TO SLIGHTLY
INCREASE WINDS OVER THE COASTAL WATERS AND HAVE ISSUED SMALL CRAFT
EXERCISE CAUTION FLAGS FOR THIS AFTN. THESE FLAGS MIGHT NEED TO BE
EXTENDED INTO TONIGHT. THESE STRONGER EASTERLY WINDS MAY ALSO HAVE
IMPACTS ON LOCAL TIDES (WHICH ARE CURRENTLY RUNNING ABOUT 1-1.5 FT
ABOVE NORMAL). 41
AVIATION...
PER SHORT-RANGE MODELS WE SHOULD HAVE A VERY DISTINCT LINE OF HAVE
AND HAVE NOTS WITH RESPECT TO PCPN. THE BOUNDARY LOOKS TO BE RIGHT
ALONG I-10. AS SUCH NO REAL ARGUMENTS WITH THE GOING TAF SET UP OF
KEEPING THE MENTION OF VCTS PRIMARILY SOUTH OF HOU. WILL HAVE SOME
ISSUES WITH SUN NIGHT/OVERNIGHT INTO MON WITH THE RE-START OF PCPN
AS THE WEAK TROPICAL WAVE CONTINUES TO AFFECT OUR WX. 41
SMOKE...
ERLY TRANSPORT WINDS WILL CONTINUE TO BRING SOME SMOKE INTO THE
HOUSTON/GALVESTON & SURROUNDING AREAS FROM AN ONGOING WILDFIRE IN
SOUTHERN JEFFERSON COUNTY (NEAR CLAM LAKE). HOPEFULLY THIS FIRE
WILL ENCOUNTER SOME RAINFALL TODAY AND LESSEN IMPACTS.
BUT...YES...THAT`S WHAT MANY OF US ARE SEEING AND SMELLING THIS
MORNING. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 74 96 75 / 20 30 10 20 10
HOUSTON (IAH) 75 90 75 95 75 / 30 40 20 30 10
GALVESTON (GLS) 79 88 80 91 81 / 60 60 30 40 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 10 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: MATAGORDA BAY...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1158 PM CDT SAT AUG 24 2013
.UPDATE...
06Z TAF DISCUSSION IN AVIATION SECTION.
&&
.AVIATION...
KCLL/KUTS/KCXO...SHOULD HAVE VFR CIGS TONIGHT WITH MAYBE AN HOUR
OR SO OF 5SM AT KCXO IN THE MORNING BUT WILL NOT MENTION IN TAF.
CONVECTION WILL BE MAIN ISSUE TOMORROW AS TROPICAL WAVE MOVES
INLAND SLOWLY. MAY SEE A FEW SHOWERS A KCXO BUT THINK MAJORITY OF
CONVECTION STAYS SOUTH OF THESE TERMINALS. OVERALL NOT MUCH CHANGE
FROM THE 00Z TAF THINKING.
KIAH/KHOU/KSGR...EXPECT VFR CIGS TONIGHT BUT INCREASING CLOUDS
THROUGH THE MORNING. MAIN ISSUE WILL BE THE ONSET OF CONVECTION
WITH TROPICAL WAVE MOVING INLAND. TROPICAL MOISTURE MAY BE SLOW TO
MOVE INLAND SO THINK KIAH WILL BE ON EDGE OF CONVECTION. LOOKS
LIKE THE 00Z MODEL RUNS ARE IN LINE WITH CURRENT TAF THINKING. DID
TWEAK TIMING A BIT AND ADDED VCTS FOR KSGR/KHOU FOR EARLY
AFTERNOON HOURS. ALSO INCREASED WIND FOR AFTERNOON AS PRESSURE
GRADIENT TIGHTENS.
KLBX/KGLS...MAIN ISSUE WILL BE SHRA DEVELOPING IN THE MORNING AND
MOVING INLAND AS TROPICAL WAVE MOVES INLAND. WILL START VCSH AT
09Z FOR BOTH TERMINALS THEN DEVELOPING VCTS BY 15Z WITH MORE
DAYTIME HEATING AND INCREASED TROPICAL MOISTURE. THINK THERE COULD
BE A GOOD PERIOD OF SCT TSRA FOR BOTH TERMINALS FROM 15-21Z. FOR
NOW WILL LEAVE VCTS GIVEN SCT NATURE OF CONVECTION. POSSIBLE TO
TEMPO TSRA WITH APPROACHING CONVECTIVE CELLS.
39
&&
.PREV DISCUSSION... /ISSUED 1004 PM CDT SAT AUG 24 2013/
UPDATE...
POPS AND WEATHER GRIDS FOR TONIGHT AND SUNDAY.
DISCUSSION...
EQUIPMENT ISSUE OF NOTE...THE GALVESTON TEMPERATURE IS TOO COOL.
TECHNICIANS WILL CHECK OUT THE EQUIPMENT SOMETIME DURING THE NEXT
24 TO 48 HOURS.
00Z ANALYSIS AND MODEL FORECASTS PLACE THE EASTERLY WAVE OVER THE
NORTHERN GULF ALONG THE LA COAST INTO THE CENTRAL GULF OF MEXICO.
BOTH THE RAP AND NAM12 700 TO 300 MEAN LAYER FORECAST SHOWS THAT A
SMALLER LOW PRESSURE TROUGH WILL APPROACH THE UPPER TEXAS COAST
OVERNIGHT TONIGHT WITH THE MAIN WAVE THEN MOVING TO ALONG THE
COAST DURING THE MID MORNING SUNDAY. BOTH MODELS KEEP THE BEST
LAYER MOISTURE AND LIFT ALONG THE INTERSTATE 10 CORRIDOR SOUTH
DURING THE MIDDAY AND AFTERNOON PERIOD. THE RIDGE TO THE NORTH MAY
BE TOO MUCH FOR THE WAVE TO OVERCOME. EXPECT THE MAIN BULK OF THE
RAIN CHANCES WILL OCCUR ALONG AND EAST OF THE WAVE AXIS...AND
THERE MAY WELL BE A FAIRLY BIG DISCONTINUITY BETWEEN NO TO
ISOLATED COVERAGE AND BE BULK OF THE ACTIVITY. FOR THAT REASON
WILL ADJUST THE POPS DOWNWARD OVER THE INLAND AREAS TONIGHT AND
FROM THE INTERSTATE 10 CORRIDOR NORTHWARD ON SUNDAY. ADJUSTED THE
POPS SLIGHTLY DOWNWARD ELSEWHERE AS WELL BOTH PERIODS.
40
PREV DISCUSSION... /ISSUED 642 PM CDT SAT AUG 24 2013/
DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.
AVIATION...
KCLL/KUTS/KCXO...OVER SHOULD HAVE VFR CIGS WITH MAYBE AN HOUR OR
SO OF 5SM AT KCXO IN THE MORNING BUT WILL NOT MENTION IN TAF.
CONVECTION WILL BE MAIN ISSUE TOMORROW AS TROPICAL WAVE MOVES
INLAND SLOWLY. MAY SEE A FEW SHOWERS A KCXO BUT THINK MAJORITY OF
CONVECTION STAYS SOUTH OF THESE TERMINALS.
KIAH/KHOU/KSGR...EXPECT VFR CIGS TONIGHT BUT INCREASING CLOUDS
THROUGH THE MORNING. MAIN ISSUE WILL BE THE ONSET OF CONVECTION
WITH TROPICAL WAVE MOVING INLAND. TROPICAL MOISTURE MAY BE SLOW TO
MOVE INLAND SO THINK KIAH WILL BE ON EDGE OF CONVECTION. WILL
MENTION VCSH FOR ALL TAFS STARTING EARLIER IN THE DAY FOR
KHOU/KSGR AND IN THE AFTERNOON FOR KIAH. WILL NEED TO EVALUATE
VCTS FOR KHOU/KSGR FOR 17Z-20Z TIME FRAME FOR 06Z TAFS BASED ON
00Z MODEL RUNS. RIGHT NOW MORE CONFIDENT IN TS FOR KHOU/KSGR THAN
KIAH. THINK 00Z MODEL RUNS WILL GIVE BETTER IDEA. ALSO INCREASED
WIND FOR AFTERNOON AS PRESSURE GRADIENT TIGHTENS.
KLBX/KGLS...MAIN ISSUE WILL BE SHRA DEVELOPING IN THE MORNING AND
MOVING INLAND AS TROPICAL WAVE MOVES INLAND. WILL START VCSH AT
09Z FOR BOTH TERMINALS THEN DEVELOPING VCTS BY 15Z WITH MORE
DAYTIME HEATING AND INCREASED TROPICAL MOISTURE. THINK THERE COULD
BE A GOOD PERIOD OF SCT TSRA FOR BOTH TERMINALS FROM 15-21Z. WILL
HOLD OFF ON TEMPO TSRA AND USE 00Z MODELS TO EVALUATE IF THERE
WILL BE A TIME FRAME FOR MORE PRONOUNCED TSRA.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 94 75 94 74 / 10 30 20 40 20
HOUSTON (IAH) 77 92 75 91 75 / 10 40 40 50 20
GALVESTON (GLS) 79 87 79 87 80 / 30 50 60 60 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AREA FORECAST DISCUSSION
NWS SPOKANE WA
237 PM PDT Sun Aug 25 2013
.SYNOPSIS...
The moist southwest flow the region has been in over the past week
or so will once again bring the chance for showers and
thunderstorms this afternoon into the overnight hours. As we move
into the work week precipitation chances will diminish with only the
higher terrain having a decent chance for activity. Another
weather system over the weekend will raise chances for widespread
precipitation once again.
&&
.DISCUSSION...
Tonight through Monday evening: The big picture includes a large
ridge of high pressure centered near Missouri and a large trof of
low pressure over the northeast Pacific. The semi-permanent trof
has been providing the Pacific Northwest with a busy
pattern...namely disturbances rotating around the base and
bringing enhanced chances of precipitation to the region. The most
recent upper level wave is evident on water vapor satellite
imagery moving inland near the California/Oregon coast. Clouds are
streaming ahead of this system throughout the inland northwest.
More importantly showers and thunderstorms are developing over
Oregon that will migrate toward the inland northwest this evening.
Overnight convection: isolated to scattered thunderstorms (some
severe this afternoon) in Oregon will eventually morph into a
large rain shield with embedded thunderstorms as it moves into
central and eastern Washington. The concern with our thermal
profile is the potential for a gust front along and ahead of the
line of storms. The latest runs of the HRRR support this with a
large band of rain and possible gust front heading north across
the state late this evening through the late night hours. We have
increased our chances of precipitation with this feature as well
as added wording about the potential for gusty winds. With each
run of the HRRR, the speeds of the storms are increasing so will
have to monitor close this evening and update as necessary. Still
some weak elevated instability remains on the back side of the
wave so a few showers still possible overnight.
Monday: Weather pattern quiets down for most of the region as the
next wave approaches Monday. The majority of the energy associated
with this wave will affect the northwest part of the state leaving
the inland northwest under partly cloudy skies with just a few
showers and thunderstorms possible in the afternoon and evening.
The exception will be near the Cascade crest where scattered
showers and isolated thunderstorms will again develop in the
afternoon and evening hours. The relatively quick storm motion
with these storms as well as tonights activity will minimize the
threat of flooding. Precipitable water values remain 120-180% of
normal for this time of the year so what isolated activity does
develop will be wet...minimizing the potential for dry lightning
strikes. /AB
Monday Night through Thursday Evening...The Inland Northwest will be
sandwiched between the trough of low pressure moving south toward
along the BC coast and a hefty ridge of high pressure anchored
over the central portion of the country. The tug-of-war will be
pulled to the slightly retrograding ridge for Tuesday and
especially Wednesday, and the temperature forecast shows this with
readings 5 to 8 degrees above normal by midweek. After that, a
disturbance rounding the trough will begin the breakdown of the
ridge for our region, and opening the door for the weekend system
to follow on its heels. Cooling temperatures closer to normal
Thursday also look likely as a front traverses eastern Washington
and the Idaho panhandle.
As far as precipitation goes, the Cascades should remain under the
influence of the trough and any minor shortwave that moves over
western Washington Tuesday and Wednesday. Precipitation chances
were not changed much from previous forecasts, which keeps slight
chances along and just east of the crest. Farther east, there may
be a few showers/thunderstorms that move north in the monsoonal
flow, although these chances look to be highest south and east of
the ID panhandle. As the shortwave on Thursday moves east,
slightly higher chances will exist over mainly the higher terrain,
although some of the precipitation may move into the valleys. ty
Thursday Night through Saturday Night: Starting the period we will
be in the never ending SW flow that will continue to bring chances
of showers and t-storms mainly in the higher elevations. The
system will send a final frontal wave through Friday afternoon into
the overnight that will bring a good chance for rain and
thunderstorms for the Cascades...the NE Mtns of WA and the ID
Panhandle. Models are finally showing the persistent trough and
associated low pressure system will eject into the region next
weekend. Where models lack consistency is the track and exact
timing of the system passage. The GFS would bring the system
onshore on the Oregon coast whereas the EC would bring it onshore
on the Washington coast. Regardless the region will see widespread
rain showers and the threat for thunderstorms. Models are showing
a pretty good amount of associated moisture with the system and
when it reaches the Cascades rain will be expected. With the
Cascades expected to receive a fair amount of rain we will have
to monitor the area for Hydrology concerns. With the exit of the
system comes more uncertainties...the EC quickly exits the system
Monday whereas the GFS has the system stall over the region
bringing a much more prolonged period of precipitation. With the
event still almost a week away we have time to refine the
details...but overall next weekend looks to be wet.
Concerning other aspects of the forecast...winds look to kick up
during the daytime periods but should not bring any problems.
Temperatures will be cooling down as our flow shifts to more
westerly rather than the southwest flow. As of right now
temperatures look to drop back into the 70s and 80s by the weekend.
/Fliehman
&&
.AVIATION...
18Z TAFS: Shower activity diminished this morning with VFR and
light winds prevailing for all TAF locations. Minor diurnal wind
shifts expected late this morning through the early afternoon
hours as a more potent short wave approaches the region from the
southwest. This wave will bring a renewed threat of showers and
thunderstorms overnight. Updated from prob30 to tempo for chances
of showers tonight and may have to add a new FM group with later
updates to capture the onset of precipitation. Ceiling and
visibility generally expected to remain high with the exception
of the stronger thunderstorms embedded within tonights activity.
/Brown
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 59 79 58 83 60 88 / 50 20 10 10 10 10
Coeur d`Alene 57 79 55 83 57 88 / 50 20 10 10 10 10
Pullman 51 80 51 85 52 88 / 50 20 10 10 10 10
Lewiston 62 87 62 92 63 95 / 40 20 10 10 10 10
Colville 55 82 53 86 53 91 / 40 20 20 10 10 10
Sandpoint 53 77 50 81 50 86 / 50 20 20 10 10 10
Kellogg 56 78 56 83 56 86 / 50 20 20 10 10 10
Moses Lake 59 82 58 86 59 89 / 30 20 10 10 10 10
Wenatchee 62 81 62 85 64 88 / 40 20 10 10 10 10
Omak 60 82 58 85 59 89 / 30 30 20 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1049 PM CDT MON AUG 26 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...
ISSUED AT 745 PM CDT MON AUG 26 2013
TO ADD TO A RECENT UPDATE...A NORTHWEST SURFACE BOUNDARY AND LIKELY
A WARM FRONT WAS NOW DEVELOPING FROM AROUND RPD TO CWA TO GRB.
SURFACE DEW POINTS WERE INCREASING ALONG AND NEAR THE BOUNDARY
WITH SOUTHEAST WINDS NOTED NORTH OF THE FRONT AND SOUTHWEST AND
WARMER TEMPERATURES SOUTH. CONVECTION SOUTH OF DLH MAY TEND TO
WORK ALONG THIS BOUNDARY LATER TONIGHT...BUT STORMS SO FAR
UPSTREAM FAIRLY SCATTERED OVER MINNESOTA FOR A FOCUS OF HEAVY RAIN.
UPDATE
ISSUED AT 713 PM CDT MON AUG 26 2013
CONVECTION ONGOING AROUND THE DLH AREA AND POINTS WEST AS A SHORT
WAVE RIDES OVER THE RIDGE THIS EVENING. EARLY TRENDS AROUND DLH
SHOWS THE STRONGER CONVECTION SOUTHWEST OF DLH NEAR THE CAP EDGE
AND DEVELOPING SOUTHEAST ALONG THIS CAP EDGE WHICH EXTENDS SOUTH
NEAR OR ALONG THE WI/MN BORDER. MORE WIDESPREAD CONVECTION NOTED NORTH
AND EAST OF DLH MOVING EAST IN THE WESTERLY FLOW. FIRST ISSUE IS
HEAVY RAIN POTENTIAL OVERNIGHT FOR A CONSIDERATION OF A FLASH
FLOOD WATCH. HEAVY RAIN FELL OVER LINCOLN AND WESTERN MARATHON
COUNTIES LAST NIGHT...AND SO THERE IS CONCERN OF MORE RAIN IN THIS
AREA. AT THIS TIME THE MORE SATURATED AIR MASS AS PER CU FIELD
THIS AFTERNOON LIES A BIT NORTH. AS A RESULT CONVECTION SHOULD
SPREAD FAIRLY RAPIDLY INTO NORTH CENTRAL WISCONSIN THIS EVENING.
WILL MONITOR SOUTHWARD PROGRESSION FOR ANY FFA HEADLINE FOR
LINCOLN AND MARATHON COUNTIES.
&&
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
MESO ANALYSIS PAGE INDICATED CAPES OF 2000/3000 J/KG AND SURFACE
BASED CONVECTIVE INHIBITION LESS THAN 50 J/KG ACROSS
NORTH-CENTRAL WISCONSIN. THERE IS A DIFFERENTIAL HEATING
BOUNDARY SET UP ACROSS NORTH CENTRAL INTO NORTHEAST WISCONSIN
THIS AFTERNOON THAT MAY BE A FOCUS FOR CONVECTION LATE THIS
AFTERNOON AND THIS EVENING. TEMPERATURES WERE IN THE LOWER TO
MIDDLE 80S ACROSS THE NORTH AND IN THE LOWER TO MIDDLE 90S SOUTH
OF THE BOUNDARY.
TRYING TO TIME CONVECTIVE COMPLEX TONIGHT AND TUESDAY WILL BE THE
MAIN PROBLEM. SINCE THE HRRR MESOSCALE MODEL DID WELL OVERNIGHT
AND THIS MORNING...WILL FOLLOW THIS MODEL FOR CONVECTIVE TRENDS
TONIGHT INTO TUESDAY MORNING. THE HRRR MODEL INDICATED A CLUSTER
OF SHOWERS AND STORMS WOULD DEVELOP AND MOVE ACROSS THE AREA
LATER THIS AFTERNOON THROUGH MID EVENING...THEN A BREAK IN THE
ACTION UNTIL CONVECTIVE COMPLEX MOVES ACROSS THE AREA AFTER
MIDNIGHT THROUGH MID TUESDAY MORNING. LATEST REGIONAL RADARS INDICATED
CONVECTION WAS TRYING TO FIRE ACROSS WESTERN WISCONSIN AT 1945Z.
AFTER THE CONVECTIVE COMPLEX EXITS THE AREA BY LATE TUESDAY
MORNING...BOUNDARY LURKING NEARBY. STILL SOME UNCERTAINTY
ON HOW CONVECTION WILL EVOLVE TOMORROW AFTERNOON AFTER THE
MORNING CONVECTION. PLENTY OF HEAT AND HUMIDITY AVAILABLE
FOR STRONG OR SEVERE STORMS LATER TOMORROW AFTERNOON. HIGHS
WILL RANGE FROM THE MIDDLE 80S NORTH TO THE LOWER TO MIDDLE 90S
SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
TEMPERATURES AND PCPN TRENDS ARE THE PRIMARY FCST CONCERNS.
THE COLD FRONT AND WEAK S/W TROF SHOULD GENERATE SCT STG/SVR TSTMS
OVER OUR SE COUNTIES ON TUESDAY EVG...FOLLOWED BY DRY CONDITIONS
FOR THE OVERNIGHT HOURS.
HIGH PRESSURE WILL BRING DRIER AND A LITTLE COOLER WEATHER TO THE
REGION WEDS INTO THU MORNING...BUT RETURN FLOW ON THE NW PERIPHERY
OF THE HIGH MAY BRING PCPN BACK INTO OUR NW COUNTIES BY THURSDAY
AFTERNOON. A WARM AND FAIRLY HUMID AIR MASS SHOULD RETURN TO
THE FORECAST AREA INTO THE WEEKEND...UNTIL A COLD FRONT MOVES
THROUGH ON SUNDAY OR SUNDAY NIGHT. SO...SMALL PCPN CHANCES WILL
CONTINUE DURING THE PERIOD.
MODELS HAVE A BIG DISPARITY IN H8 TEMPS NEXT MONDAY...WITH THE
ECMWF SHOWING A MUCH MORE AMPLIFIED UPPER LEVEL PATTERN AND
MUCH COOLER TEMPS THAN THE GFS/GEFS. NOTICE THAT THE 12Z ECMWF
WAS NOT QUITE AS COLD AS THE PREV RUN...AND IS CLOSER TO THE
ECMWF ENSEMBLE MEAN...SO A COMPROMISE IS IN ORDER. HAVE GONE
WITH SOME MODEST COOLING ON MONDAY...BUT NOTHING AS DRASTIC
AS THE ECMWF SHOWS.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1049 PM CDT MON AUG 26 2013
MAINLY STRATIFORM TYPE PRECIPITATION WITH EMBEDDED
STORMS OVER NORTH CENTRAL WISCONSIN CONTINUES TO SPREAD SOUTHEAST
OVERNIGHT. SCATTERED MVFR CIGS AND VSBYS WITH SHOWERS AND STORMS
OVERNIGHT WITH PERHAPS POCKETS OF IFR CIGS LATE TONIGHT OVER NORTH
CENTRAL WISCONSIN. WITH THE FRONT STILL GRADUALLY DROPPING SOUTH
ON TUESDAY...SCATTERED MVFR CIGS AND VSBYS DUE TO CONVECTION WILL
CONTINUE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 AM CDT TUESDAY FOR WIZ018-030.
&&
$$
UPDATE.........TDH
SHORT TERM.....ECKBERG
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
928 PM CDT MON AUG 26 2013
.UPDATE...
NO CHANGES TO THE FORECAST FOR TONIGHT/TUESDAY AT THIS TIME. HEAT
ADVISORY LOOKS ON TRACK WITH AFTERNOON HIGHS IN THE LOWER 90S AND
MAX HEAT INDEX VALUES IN THE LOWER 100S FOR ALL EXCEPT THE NORTHEAST
MKX FORECAST AREA.
THERE IS A SURFACE FRONT THAT EXTENDS FROM LOW PRESSURE OVER SOUTH
DAKOTA THROUGH CENTRAL MN...NORTHWEST/WEST CENTRAL WI AND DOWN TO
AROUND THE SHEBOYGAN AREA. JUST NORTH OF THE SURFACE FRONT LIES AN
850MB TEMPERATURE GRADIENT THROUGH NORTH CENTRAL MN AND NORTHERN
WI...COINCIDENT WITH THE NOSE OF THE SOUTHWEST LOW LEVEL JET...500MB
VORTICITY ADVECTION AND THE LEADING EDGE OF A WESTERLY 45 KNOT 500MB
WIND MAX. THESE CONDITIONS ARE SUPPORTING CONVECTION THAT IS
CONGEALING INTO A MESOSCALE CONVECTIVE COMPLEX WITH COOLING CLOUD
TOPS PER INFRARED SATELLITE IMAGERY.
THE 00Z HRRR CONTINUES TO INITIATE CONVECTION OVER EAST CENTRAL WI
THIS EVENING AND MOVE IT EAST...POSSIBLY CLIPPING FOND DU LAC AND
SHEBOYGAN IN THE NORTHEAST MKX FORECAST AREA. NOT SEEING SIGNS OF
THIS DEVELOPING QUITE YET BUT CANNOT RULE IT OUT GIVEN THE VICINITY
OF THE FRONT AND HIGH PRECIPITABLE WATER AND ELEVATED CAPE OF
1600-1800 J/KG.
THE TRAILING STORMS OVER NORTH CENTRAL WI AND ANY CONVECTION BEHIND
THAT ARE EXPECTED TO TRACK EAST-SOUTHEAST TONIGHT WITH THE VEERING
LOW LEVEL JET AND COULD CLIP THE MKX FORECAST AREA LATE
TONIGHT/TUESDAY MORNING. THUS...CHANCES FOR STORMS IN THE NORTHEAST
HALF OF THE FORECAST AREA SEEM REASONABLE.
&&
.AVIATION/06Z TAFS/...
THERE WILL BE A CHANCE FOR SHOWERS AND STORMS AFTER MIDNIGHT TONIGHT
INTO TUESDAY MORNING AND AGAIN TUESDAY AFTERNOON. THE BEST CHANCE
WILL BE NORTHEAST OF A LONE ROCK TO KENOSHA LINE. OTHERWISE...
PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE DAY TUESDAY.
SIMILAR TO MONDAY MORNING...CONVECTION OVERNIGHT AND/OR TOMORROW MAY
KICK OUT AN OUTFLOW BOUNDARY AND RESULT IN A WIND SWITCH FOR A
COUPLE HOURS. OTHERWISE...SOUTHWEST WINDS WILL CONTINUE THROUGH TUE
AFTERNOON.
A COLD FRONT WILL SLOWLY DROP SOUTHWESTWARD THROUGH SOUTHERN WI
TUESDAY NIGHT. ANY AFTERNOON CONVECTION ALONG THIS FRONT WILL
DIMINISH DURING THE EVENING AND LIKELY GO THROUGH SOUTHWEST WI DRY.
WINDS WILL BECOME NORTHEAST TO NORTH BEHIND THIS FRONT.
&&
.PREV DISCUSSION... /ISSUED 330 PM CDT MON AUG 26 2013/
SHORT TERM...
TONIGHT AND TUESDAY...FORECAST CONFIDENCE MEDIUM
SHOULD BE QUIET LATE THIS AFTERNOON INTO EARLY EVENING. AFTER
THAT...WILL BE MONITORING THE POTENTIAL FOR CONVECTION ACROSS
NORTHEAST PORTIONS OF THE FORECAST AREA. ALREADY SEEING SOME
ACTIVITY IN NORTHWEST WISCONSIN...AND THINK MORE DEVELOPMENT WILL
OCCUR INTO THE EVENING WITHIN TIGHTEST THERMAL GRADIENT ALOFT FROM
NORTHWEST TO EAST-CENTRAL WISCONSIN. MODELS NOT IN GREAT AGREEMENT
WITH TIMING OF CONVECTION THROUGH TOMORROW...SO GENERALLY JUST KEPT
CHANCE POPS GOING IN THE NORTHEAST THE WHOLE TIME.
OTHER ISSUES ARE TEMPERATURES AND HEAT INDICES FOR TOMORROW. SIMILAR
TO EARLIER TODAY...THERE COULD BE PRECIP ALONG WITH A LARGE AREA OF
CONVECTIVE DEBRIS THROUGH A GOOD PART OF THE DAY. EVEN SO...WITH
VERY WARM TEMPS ALOFT...IT WILL NOT TAKE MUCH SUNSHINE TO BOOST
TEMPS QUITE A BIT. SO...OPTED TO KEEP HIGH TEMPS SIMILAR TO WHAT HAS
BEEN IN THE FORECAST. THIS RESULTS IN HEAT INDICES IN THE MID 90S TO
LOW 100S ACROSS THE FORECAST AREA. WITH FAIRLY WIDESPREAD VALUES OF
AT LEAST 100 DEGREES...DECIDED TO GO WITH A HEAT ADVISORY FOR A GOOD
PORTION OF THE AREA...LEAVING OUT NORTHEAST COUNTIES BECAUSE OF THE
CONVECTIVE POTENTIAL.
TUESDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
A WEAK COLD FRONT WILL SLIDE SLOWLY SWD THROUGH THE AREA TUE
NIGHT. SCT TSTORMS WILL LIKELY BE ONGOING OVER EAST CENTRAL WI
DURING THE DAY AND WILL LIKELY LINGER INTO THE EVENING...GIVEN A
VORTICITY MAXIMUM TRACKING ACROSS THAT AREA AND CONTINUED MOISTURE
TRANSPORT FROM THE LLJ. ADDITIONAL TSTORM DEVELOPMENT IS POSSIBLE
TO THE SOUTH BUT CHANCES ARE LOW GIVEN THE TRACK OF THE VORT MAX
TO THE NORTH AND A WEAKENING LOW LEVEL JET AS IT SHIFTS SWD.
A LGT NELY FLOW WILL BRING A SOMEWHAT COOLER AND DRIER AIRMASS TO
SRN WI ON WED. HIGH PRESSURE WILL THEN BUILD INTO THE AREA WED NT
AND THU. TEMPS WILL COOL TO NEAR SEASONAL NORMAL WED NT GIVEN THE
GOOD RADIATIONAL COOLING CONDITIONS. 925 MB TEMPS AROUND 24C WILL
SUPPORT UPPER 80 TEMPS FOR BOTH WED-THU. ONSHORE FLOW WILL KEEP
HIGH TEMPS IN THE LOWER 80S NEAR THE LAKE.
LONG TERM...
THURSDAY NIGHT THROUGH LABOR DAY...FORECAST CONFIDENCE MEDIUM
A BROAD UPPER RIDGE WILL CONTINUE OVER THE SOUTH CENTRAL USA
THROUGH THE PERIOD. A WEAK WAVE OF SFC LOW PRESSURE APPROACHING FROM
THE NRN PLAINS WILL BRING CHANCES OF TSTORMS FROM THU NT INTO SAT.
VERY WARM...HUMID...AND UNSTABLE CONDITIONS WILL CONTINUE DURING THIS
TIME.
STRONG CYCLOGENESIS WILL THEN ENSUE ACROSS SRN CANADA WITH
THE ECMWF FASTER AND STRONGER WITH THE EVOLUTION THAN THE CANADIAN
OR GFS. A CONSENSUS WOULD BRING A COLD FRONT...POSSIBLY DRY...THROUGH
THE REGION SUN NT WITH SOME COOLING OF THE TEMPS FOR LABOR DAY.
THERE IS A LARGE RANGE IN TEMP POSSIBILITIES FOR LABOR DAY AT
THIS TIME AND BELIEVE TEMPS WILL LIKELY TREND DOWNWARD AS WE
APPROACH LABOR DAY.
AVIATION/00Z TAFS/...
THERE WILL BE A CHANCE FOR SHOWERS AND STORMS AGAIN TONIGHT INTO
TUESDAY...THE BEST CHANCE NORTHEAST OF A LONE ROCK TO KENOSHA LINE.
OTHERWISE...PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE DAY
TUESDAY.
SIMILAR TO EARLIER TODAY...CONVECTION TONIGHT AND/OR TOMORROW MAY
KICK OUT AN OUTFLOW BOUNDARY AND RESULT IN A WIND SWITCH FOR A
COUPLE HOURS. OTHERWISE...SOUTHWEST WINDS WILL CONTINUE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR WIZ046-056-057-
062>072.
LM...NONE.
&&
$$
UPDATE...MRC
TONIGHT/TUESDAY AND AVIATION/MARINE...DDV
TUESDAY NIGHT THROUGH MONDAY...GEHRING
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
748 PM CDT MON AUG 26 2013
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 745 PM CDT MON AUG 26 2013
TO ADD TO A RECENT UPDATE...A NORTHWEST SURFACE BOUNDARY AND LIKELY
A WARM FRONT WAS NOW DEVELOPING FROM AROUND RPD TO CWA TO GRB.
SURFACE DEW POINTS WERE INCREASING ALONG AND NEAR THE BOUNDARY
WITH SOUTHEAST WINDS NOTED NORTH OF THE FRONT AND SOUTHWEST AND
WARMER TEMPERATURES SOUTH. CONVECTION SOUTH OF DLH MAY TEND TO
WORK ALONG THIS BOUNDARY LATER TONIGHT...BUT STORMS SO FAR
UPSTREAM FAIRLY SCATTERED OVER MINNESOTA FOR A FOCUS OF HEAVY RAIN.
UPDATE
ISSUED AT 713 PM CDT MON AUG 26 2013
CONVECTION ONGOING AROUND THE DLH AREA AND POINTS WEST AS A SHORT
WAVE RIDES OVER THE RIDGE THIS EVENING. EARLY TRENDS AROUND DLH
SHOWS THE STRONGER CONVECTION SOUTHWEST OF DLH NEAR THE CAP EDGE
AND DEVELOPING SOUTHEAST ALONG THIS CAP EDGE WHICH EXTENDS SOUTH
NEAR OR ALONG THE WI/MN BORDER. MORE WIDESPREAD CONVECTION NOTED NORTH
AND EAST OF DLH MOVING EAST IN THE WESTERLY FLOW. FIRST ISSUE IS
HEAVY RAIN POTENTIAL OVERNIGHT FOR A CONSIDERATION OF A FLASH
FLOOD WATCH. HEAVY RAIN FELL OVER LINCOLN AND WESTERN MARATHON
COUNTIES LAST NIGHT...AND SO THERE IS CONCERN OF MORE RAIN IN THIS
AREA. AT THIS TIME THE MORE SATURATED AIR MASS AS PER CU FIELD
THIS AFTERNOON LIES A BIT NORTH. AS A RESULT CONVECTION SHOULD
SPREAD FAIRLY RAPIDLY INTO NORTH CENTRAL WISCONSIN THIS EVENING.
WILL MONITOR SOUTHWARD PROGRESSION FOR ANY FFA HEADLINE FOR
LINCOLN AND MARATHON COUNTIES.
&&
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
MESO ANALYSIS PAGE INDICATED CAPES OF 2000/3000 J/KG AND SURFACE
BASED CONVECTIVE INHIBITION LESS THAN 50 J/KG ACROSS
NORTH-CENTRAL WISCONSIN. THERE IS A DIFFERENTIAL HEATING
BOUNDARY SET UP ACROSS NORTH CENTRAL INTO NORTHEAST WISCONSIN
THIS AFTERNOON THAT MAY BE A FOCUS FOR CONVECTION LATE THIS
AFTERNOON AND THIS EVENING. TEMPERATURES WERE IN THE LOWER TO
MIDDLE 80S ACROSS THE NORTH AND IN THE LOWER TO MIDDLE 90S SOUTH
OF THE BOUNDARY.
TRYING TO TIME CONVECTIVE COMPLEX TONIGHT AND TUESDAY WILL BE THE
MAIN PROBLEM. SINCE THE HRRR MESOSCALE MODEL DID WELL OVERNIGHT
AND THIS MORNING...WILL FOLLOW THIS MODEL FOR CONVECTIVE TRENDS
TONIGHT INTO TUESDAY MORNING. THE HRRR MODEL INDICATED A CLUSTER
OF SHOWERS AND STORMS WOULD DEVELOP AND MOVE ACROSS THE AREA
LATER THIS AFTERNOON THROUGH MID EVENING...THEN A BREAK IN THE
ACTION UNTIL CONVECTIVE COMPLEX MOVES ACROSS THE AREA AFTER
MIDNIGHT THROUGH MID TUESDAY MORNING. LATEST REGIONAL RADARS INDICATED
CONVECTION WAS TRYING TO FIRE ACROSS WESTERN WISCONSIN AT 1945Z.
AFTER THE CONVECTIVE COMPLEX EXITS THE AREA BY LATE TUESDAY
MORNING...BOUNDARY LURKING NEARBY. STILL SOME UNCERTAINTY
ON HOW CONVECTION WILL EVOLVE TOMORROW AFTERNOON AFTER THE
MORNING CONVECTION. PLENTY OF HEAT AND HUMIDITY AVAILABLE
FOR STRONG OR SEVERE STORMS LATER TOMORROW AFTERNOON. HIGHS
WILL RANGE FROM THE MIDDLE 80S NORTH TO THE LOWER TO MIDDLE 90S
SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
TEMPERATURES AND PCPN TRENDS ARE THE PRIMARY FCST CONCERNS.
THE COLD FRONT AND WEAK S/W TROF SHOULD GENERATE SCT STG/SVR TSTMS
OVER OUR SE COUNTIES ON TUESDAY EVG...FOLLOWED BY DRY CONDITIONS
FOR THE OVERNIGHT HOURS.
HIGH PRESSURE WILL BRING DRIER AND A LITTLE COOLER WEATHER TO THE
REGION WEDS INTO THU MORNING...BUT RETURN FLOW ON THE NW PERIPHERY
OF THE HIGH MAY BRING PCPN BACK INTO OUR NW COUNTIES BY THURSDAY
AFTERNOON. A WARM AND FAIRLY HUMID AIR MASS SHOULD RETURN TO
THE FORECAST AREA INTO THE WEEKEND...UNTIL A COLD FRONT MOVES
THROUGH ON SUNDAY OR SUNDAY NIGHT. SO...SMALL PCPN CHANCES WILL
CONTINUE DURING THE PERIOD.
MODELS HAVE A BIG DISPARITY IN H8 TEMPS NEXT MONDAY...WITH THE
ECMWF SHOWING A MUCH MORE AMPLIFIED UPPER LEVEL PATTERN AND
MUCH COOLER TEMPS THAN THE GFS/GEFS. NOTICE THAT THE 12Z ECMWF
WAS NOT QUITE AS COLD AS THE PREV RUN...AND IS CLOSER TO THE
ECMWF ENSEMBLE MEAN...SO A COMPROMISE IS IN ORDER. HAVE GONE
WITH SOME MODEST COOLING ON MONDAY...BUT NOTHING AS DRASTIC
AS THE ECMWF SHOWS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 619 PM CDT MON AUG 26 2013
CONVECTION WEST OF DLH WILL SPREAD AND DEVELOP INTO
NORTHERN WISCONSIN THIS EVENING ALONG AND NORTH OF A BOUNDARY
EXTENDING FROM DLH TO AIG. AS A RESULT EXPECT ISOLD CONVECTION
THIS EVENING TO BECOME MORE WIDESPREAD LATER THIS EVENING.
CONVECTION WILL LIKELY DEVELOP SOUTHWARD LATE TONIGHT INTO CENTRAL
WISCONSIN WITH SATURATION SOUTH OF THE BOUNDARY. CONVECTION MORE
THAN LIKELY TO BE ONGOING IN THE MORNING ALONG THE BOUNDARY BEFORE
DIMINISHING ACROSS THE NORTH AS THE FRONT SHIFTS SOUTH.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........TDH
SHORT TERM.....ECKBERG
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
714 PM CDT MON AUG 26 2013
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 713 PM CDT MON AUG 26 2013
CONVECTION ONGOING AROUND THE DLH AREA AND POINTS WEST AS A SHORT
WAVE RIDES OVER THE RIDGE THIS EVENING. EARLY TRENDS AROUND DLH
SHOWS THE STRONGER CONVECTION SOUTHWEST OF DLH NEAR THE CAP EDGE
AND DEVELOPING SOUTHEAST ALONG THIS CAP EDGE WHICH EXTENDS SOUTH
NEAR OR ALONG THE WI/MN BORDER. MORE WIDESPREAD CONVECTION NOTED NORTH
AND EAST OF DLH MOVING EAST IN THE WESTERLY FLOW. FIRST ISSUE IS
HEAVY RAIN POTENTIAL OVERNIGHT FOR A CONSIDERATION OF A FLASH
FLOOD WATCH. HEAVY RAIN FELL OVER LINCOLN AND WESTERN MARATHON
COUNTIES LAST NIGHT...AND SO THERE IS CONCERN OF MORE RAIN IN THIS
AREA. AT THIS TIME THE MORE SATURATED AIR MASS AS PER CU FIELD
THIS AFTERNOON LIES A BIT NORTH. AS A RESULT CONVECTION SHOULD
SPREAD FAIRLY RAPIDLY INTO NORTH CENTRAL WISCONSIN THIS EVENING.
WILL MONITOR SOUTHWARD PROGRESSION FOR ANY FFA HEADLINE FOR
LINCOLN AND MARATHON COUNTIES.
&&
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
MESO ANALYSIS PAGE INDICATED CAPES OF 2000/3000 J/KG AND SURFACE
BASED CONVECTIVE INHIBITION LESS THAN 50 J/KG ACROSS
NORTH-CENTRAL WISCONSIN. THERE IS A DIFFERENTIAL HEATING
BOUNDARY SET UP ACROSS NORTH CENTRAL INTO NORTHEAST WISCONSIN
THIS AFTERNOON THAT MAY BE A FOCUS FOR CONVECTION LATE THIS
AFTERNOON AND THIS EVENING. TEMPERATURES WERE IN THE LOWER TO
MIDDLE 80S ACROSS THE NORTH AND IN THE LOWER TO MIDDLE 90S SOUTH
OF THE BOUNDARY.
TRYING TO TIME CONVECTIVE COMPLEX TONIGHT AND TUESDAY WILL BE THE
MAIN PROBLEM. SINCE THE HRRR MESOSCALE MODEL DID WELL OVERNIGHT
AND THIS MORNING...WILL FOLLOW THIS MODEL FOR CONVECTIVE TRENDS
TONIGHT INTO TUESDAY MORNING. THE HRRR MODEL INDICATED A CLUSTER
OF SHOWERS AND STORMS WOULD DEVELOP AND MOVE ACROSS THE AREA
LATER THIS AFTERNOON THROUGH MID EVENING...THEN A BREAK IN THE
ACTION UNTIL CONVECTIVE COMPLEX MOVES ACROSS THE AREA AFTER
MIDNIGHT THROUGH MID TUESDAY MORNING. LATEST REGIONAL RADARS INDICATED
CONVECTION WAS TRYING TO FIRE ACROSS WESTERN WISCONSIN AT 1945Z.
AFTER THE CONVECTIVE COMPLEX EXITS THE AREA BY LATE TUESDAY
MORNING...BOUNDARY LURKING NEARBY. STILL SOME UNCERTAINTY
ON HOW CONVECTION WILL EVOLVE TOMORROW AFTERNOON AFTER THE
MORNING CONVECTION. PLENTY OF HEAT AND HUMIDITY AVAILABLE
FOR STRONG OR SEVERE STORMS LATER TOMORROW AFTERNOON. HIGHS
WILL RANGE FROM THE MIDDLE 80S NORTH TO THE LOWER TO MIDDLE 90S
SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
TEMPERATURES AND PCPN TRENDS ARE THE PRIMARY FCST CONCERNS.
THE COLD FRONT AND WEAK S/W TROF SHOULD GENERATE SCT STG/SVR TSTMS
OVER OUR SE COUNTIES ON TUESDAY EVG...FOLLOWED BY DRY CONDITIONS
FOR THE OVERNIGHT HOURS.
HIGH PRESSURE WILL BRING DRIER AND A LITTLE COOLER WEATHER TO THE
REGION WEDS INTO THU MORNING...BUT RETURN FLOW ON THE NW PERIPHERY
OF THE HIGH MAY BRING PCPN BACK INTO OUR NW COUNTIES BY THURSDAY
AFTERNOON. A WARM AND FAIRLY HUMID AIR MASS SHOULD RETURN TO
THE FORECAST AREA INTO THE WEEKEND...UNTIL A COLD FRONT MOVES
THROUGH ON SUNDAY OR SUNDAY NIGHT. SO...SMALL PCPN CHANCES WILL
CONTINUE DURING THE PERIOD.
MODELS HAVE A BIG DISPARITY IN H8 TEMPS NEXT MONDAY...WITH THE
ECMWF SHOWING A MUCH MORE AMPLIFIED UPPER LEVEL PATTERN AND
MUCH COOLER TEMPS THAN THE GFS/GEFS. NOTICE THAT THE 12Z ECMWF
WAS NOT QUITE AS COLD AS THE PREV RUN...AND IS CLOSER TO THE
ECMWF ENSEMBLE MEAN...SO A COMPROMISE IS IN ORDER. HAVE GONE
WITH SOME MODEST COOLING ON MONDAY...BUT NOTHING AS DRASTIC
AS THE ECMWF SHOWS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 619 PM CDT MON AUG 26 2013
CONVECTION WEST OF DLH WILL SPREAD AND DEVELOP INTO
NORTHERN WISCONSIN THIS EVENING ALONG AND NORTH OF A BOUNDARY
EXTENDING FROM DLH TO AIG. AS A RESULT EXPECT ISOLD CONVECTION
THIS EVENING TO BECOME MORE WIDESPREAD LATER THIS EVENING.
CONVECTION WILL LIKELY DEVELOP SOUTHWARD LATE TONIGHT INTO CENTRAL
WISCONSIN WITH SATURATION SOUTH OF THE BOUNDARY. CONVECTION MORE
THAN LIKELY TO BE ONGOING IN THE MORNING ALONG THE BOUNDARY BEFORE
DIMINISHING ACROSS THE NORTH AS THE FRONT SHIFTS SOUTH.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........TDH
SHORT TERM.....ECKBERG
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
620 PM CDT MON AUG 26 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
MESO ANALYSIS PAGE INDICATED CAPES OF 2000/3000 J/KG AND SURFACE
BASED CONVECTIVE INHIBITION LESS THAN 50 J/KG ACROSS
NORTH-CENTRAL WISCONSIN. THERE IS A DIFFERENTIAL HEATING
BOUNDARY SET UP ACROSS NORTH CENTRAL INTO NORTHEAST WISCONSIN
THIS AFTERNOON THAT MAY BE A FOCUS FOR CONVECTION LATE THIS
AFTERNOON AND THIS EVENING. TEMPERATURES WERE IN THE LOWER TO
MIDDLE 80S ACROSS THE NORTH AND IN THE LOWER TO MIDDLE 90S SOUTH
OF THE BOUNDARY.
TRYING TO TIME CONVECTIVE COMPLEX TONIGHT AND TUESDAY WILL BE THE
MAIN PROBLEM. SINCE THE HRRR MESOSCALE MODEL DID WELL OVERNIGHT
AND THIS MORNING...WILL FOLLOW THIS MODEL FOR CONVECTIVE TRENDS
TONIGHT INTO TUESDAY MORNING. THE HRRR MODEL INDICATED A CLUSTER
OF SHOWERS AND STORMS WOULD DEVELOP AND MOVE ACROSS THE AREA
LATER THIS AFTERNOON THROUGH MID EVENING...THEN A BREAK IN THE
ACTION UNTIL CONVECTIVE COMPLEX MOVES ACROSS THE AREA AFTER
MIDNIGHT THROUGH MID TUESDAY MORNING. LATEST REGIONAL RADARS INDICATED
CONVECTION WAS TRYING TO FIRE ACROSS WESTERN WISCONSIN AT 1945Z.
AFTER THE CONVECTIVE COMPLEX EXITS THE AREA BY LATE TUESDAY
MORNING...BOUNDARY LURKING NEARBY. STILL SOME UNCERTAINTY
ON HOW CONVECTION WILL EVOLVE TOMORROW AFTERNOON AFTER THE
MORNING CONVECTION. PLENTY OF HEAT AND HUMIDITY AVAILABLE
FOR STRONG OR SEVERE STORMS LATER TOMORROW AFTERNOON. HIGHS
WILL RANGE FROM THE MIDDLE 80S NORTH TO THE LOWER TO MIDDLE 90S
SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
TEMPERATURES AND PCPN TRENDS ARE THE PRIMARY FCST CONCERNS.
THE COLD FRONT AND WEAK S/W TROF SHOULD GENERATE SCT STG/SVR TSTMS
OVER OUR SE COUNTIES ON TUESDAY EVG...FOLLOWED BY DRY CONDITIONS
FOR THE OVERNIGHT HOURS.
HIGH PRESSURE WILL BRING DRIER AND A LITTLE COOLER WEATHER TO THE
REGION WEDS INTO THU MORNING...BUT RETURN FLOW ON THE NW PERIPHERY
OF THE HIGH MAY BRING PCPN BACK INTO OUR NW COUNTIES BY THURSDAY
AFTERNOON. A WARM AND FAIRLY HUMID AIR MASS SHOULD RETURN TO
THE FORECAST AREA INTO THE WEEKEND...UNTIL A COLD FRONT MOVES
THROUGH ON SUNDAY OR SUNDAY NIGHT. SO...SMALL PCPN CHANCES WILL
CONTINUE DURING THE PERIOD.
MODELS HAVE A BIG DISPARITY IN H8 TEMPS NEXT MONDAY...WITH THE
ECMWF SHOWING A MUCH MORE AMPLIFIED UPPER LEVEL PATTERN AND
MUCH COOLER TEMPS THAN THE GFS/GEFS. NOTICE THAT THE 12Z ECMWF
WAS NOT QUITE AS COLD AS THE PREV RUN...AND IS CLOSER TO THE
ECMWF ENSEMBLE MEAN...SO A COMPROMISE IS IN ORDER. HAVE GONE
WITH SOME MODEST COOLING ON MONDAY...BUT NOTHING AS DRASTIC
AS THE ECMWF SHOWS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 619 PM CDT MON AUG 26 2013
CONVECTION WEST OF DLH WILL SPREAD AND DEVELOP INTO
NORTHERN WISCONSIN THIS EVENING ALONG AND NORTH OF A BOUNDARY
EXTENDING FROM DLH TO AIG. AS A RESULT EXPECT ISOLD CONVECTION
THIS EVENING TO BECOME MORE WIDESPREAD LATER THIS EVENING.
CONVECTION WILL LIKELY DEVELOP SOUTHWARD LATE TONIGHT INTO CENTRAL
WISCONSIN WITH SATURATION SOUTH OF THE BOUNDARY. CONVECTION MORE
THAN LIKELY TO BE ONGOING IN THE MORNING ALONG THE BOUNDARY BEFORE
DIMINISHING ACROSS THE NORTH AS THE FRONT SHIFTS SOUTH.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ECKBERG
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
346 PM CDT SUN AUG 25 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 346 PM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL TONIGHT
THROUGH TUESDAY AND HEAT INDEX VALUES.
LATEST SURFACE OBSERVATIONS PLACED A WARM FRONT EXTENDING FROM
SOUTHEAST NORTH DAKOTA THROUGH NORTHERN MINNESOTA...STRETCHING
EAST OVER SOUTHERN LAKE SUPERIOR. WATER VAPOR IMAGERY AND RAP 500 MB
ANALYSIS SHOWED HIGH PRESSURE CENTERED ALONG THE KANSAS/MISSOURI BORDER
WITH A FLATTENING RIDGE EXTENDING NORTH INTO THE UPPER MISSISSIPPI RIVER
VALLEY. A FEW SUBTLE SHORTWAVES NOTED...THE FIRST WAS LOCATED OVER
THE EASTERN DAKOTAS AND ANOTHER...SLIGHTLY STRONGER WAVE...WAS
MOVING INTO EASTERN MONTANA. THE WARM FRONT AND THESE TWO WAVES WILL
BE THE MAIN FEATURES TO KEEP A CLOSE EYE ON THROUGH MONDAY MORNING.
ALSO...A PLUME OF MONSOONAL MOISTURE WAS STREAMING NORTHWARD THROUGH
THE DESERT SOUTHWEST AND INTO WESTERN NEBRASKA/SOUTH DAKOTA...HEADING EAST.
THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE WARM FRONT THIS
EVENING...THEN MOVE SOUTHWARD OVERNIGHT. IT APPEARS THAT THE STORMS
WILL INITIATE OVER EAST CENTRAL MINNESOTA INTO NORTHWEST WISCONSIN
THEN SHIFT SOUTHWARD WITH TIME DURING THE OVERNIGHT HOURS
POTENTIALLY IMPACTING AREAS NORTH OF INTERSTATE 90. CAPE VALUES
ARE RATHER IMPRESSIVE LATE THIS AFTERNOON OVER THESE AREAS...WITH
TEMPERATURES IN THE UPPER 90S AND DEWPOINTS IN THE LOWER 70S
PRODUCING 3500 TO 4000 J/KG OF SURFACE BASED CAPE. SHEAR ISN/T
OVERLY IMPRESSIVE WITH 0-6KM BULK SHEAR VALUES OF AROUND 30
KTS...MAINLY NORTH OF INTERSTATE 94. HOWEVER...THE SHEAR IS FOCUSED
IN THE 0-3 KM LAYER WHICH WOULD FAVOR THE POTENTIAL FOR LINEAR STORM
STRUCTURES WITH DAMAGING WINDS. THE HIGH INSTABILITY OVER THE AREA
SHOULD OVERCOME THE LACK OF STRONG SHEAR...LEADING TO THE POTENTIAL
FOR SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS. STRONG
850 MB MOISTURE TRANSPORT FOCUSES INTO THE WARM FRONT TONIGHT WHICH
COULD POTENTIALLY LEAD TO REPEATED ROUNDS OF THUNDERSTORMS ALONG IT.
PRECIPITABLE WATER VALUES INCREASE TO 2.0 TO 2.3 INCHES
TONIGHT...WHICH IS AROUND 230 PERCENT OF NORMAL. ALSO...WARM CLOUD
DEPTHS INCREASE TO AROUND 4.7 KM. ANY THUNDERSTORMS THAT DEVELOP IN
THIS AIRMASS WILL BE VERY EFFICIENT RAIN PRODUCERS. THESE FACTORS
COULD LEAD TO FLASH FLOODING OVER PORTIONS OF NORTHERN AND NORTH
CENTRAL WISCONSIN TONIGHT INTO EARLY MONDAY MORNING. CONFIDENCE ON
SEVERE THUNDERSTORM POTENTIAL IS HIGHEST NORTH AND EAST OF INTERSTATE
94 TONIGHT. A STRONG CAP ALONG AND SOUTH OF THESE AREAS SHOULD LIMIT
HOW FAR SOUTH CONVECTION CAN BUILD. CANNOT RULE OUT THE STORMS
MAKING IT TO THE INTERSTATE 90 CORRIDOR BUT THEY SHOULD QUICKLY
DISSIPATE IF THEY MAKE IT ANY FURTHER SOUTH AND ENCOUNTER THE
STRONG CAP.
SHOWERS AND STORMS SHOULD QUICKLY TAPER OFF EARLY MONDAY MORNING AS
MOISTURE TRANSPORT WEAKENS. DEPENDING ON HOW THE OVERNIGHT
CONVECTION PLAYS OUT...THE WARM FRONT LOOKS TO BE ORIENTED JUST
NORTH OF THE INTERSTATE 94 CORRIDOR BY LATE MONDAY MORNING INTO
MONDAY AFTERNOON. MLCAPE VALUES INCREASE INTO THE 2000 TO 3500 J/KG
RANGE ALONG THE FRONT BY MID AFTERNOON ON MONDAY. 0-6 KM BULK SHEAR
VALUES HOVER AROUND 30 KTS OVER MUCH OF NORTHERN AND CENTRAL
WISCONSIN MONDAY AFTERNOON INTO MONDAY EVENING WHICH WOULD FAVOR
SEVERE MULTICELL STORMS. WITH THE HIGH CAPE VALUES NEAR THE WARM
FRONT...CANNOT RULE OUT A FEW SUPERCELL STRUCTURES ESPECIALLY OVER
NORTHWEST INTO NORTH CENTRAL WISCONSIN. ALSO FORECAST MODELS SUGGEST
THERE COULD BE JUST ENOUGH 0-1 KM SHEAR TO SUPPORT AN ISOLATED
TORNADO OR TWO NEAR THE WARM FRONT. OTHERWISE...THE STORMS WILL BE
CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS...AND HEAVY
RAINFALL. THE SHOWERS AND STORMS WILL CONTINUE INTO MONDAY NIGHT
WITH THE HIGHEST CHANCES MAINLY ALONG AND NORTHEAST OF INTERSTATE
94.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 346 PM CDT SUN AUG 25 2013
SHOWERS AND STORMS WILL BE ONGOING TUESDAY MORNING...MAINLY ALONG
AND EAST OF THE MISSISSIPPI RIVER. A WEAK COLD FRONT IS EXPECTED TO
SWEEP ACROSS THE REGION TUESDAY AFTERNOON. A FEW SHOWERS AND STORMS
CANNOT BE RULED OUT ALONG THE FRONT TUESDAY AFTERNOON INTO TUESDAY
EVENING...BUT IT APPEARS A CAP WILL HOLD STRONG FOR AREAS WEST OF
THE MISSISSIPPI RIVER...WITH A CHANCE OF SHOWERS AND STORMS OVER MUCH
OF WESTERN INTO CENTRAL WISCONSIN. 925MB TEMPERATURES COOL INTO THE
22 TO 25 C RANGE IN THE WAKE OF THE FRONT. SO WE SHOULD SEE A VERY
SMALL RELIEF FROM THE HEAT WITH HEAT INDEX VALUES FALLING INTO THE
MID TO UPPER 90S. SURFACE HIGH PRESSURE SETTLES OVERHEAD ON THURSDAY
BRINGING SOME SLIGHTLY COOLER AIR WITH IT...WITH 925MB TEMPERATURES
FALLING TO AROUND 23 C...PRODUCING HIGHS IN THE UPPER 80S TO AROUND
90. THE HIGH SLIDES OFF TO THE EAST ON FRIDAY AS A WARM FRONT PUSHES
EAST OUT OF THE NORTHERN/CENTRAL PLAINS. WEAK SHORTWAVES ARE EXPECTED
TO INTERACT WITH THE FRONT BRINGING CHANCES FOR SHOWERS AND STORMS TO
THE AREA FROM THURSDAY AFTERNOON THROUGH FRIDAY NIGHT. MODEL
SOLUTIONS START TO DIVERGE SATURDAY INTO SUNDAY ON TIMING OF THESE
SHORTWAVES SO CONFIDENCE LOW ON PRECIPITATION CHANCES SATURDAY INTO
SUNDAY. TEMPERATURES ARE EXPECTED TO WARM SLIGHTLY FOR THE WEEKEND
WITH HIGHS CLIMBING INTO THE UPPER 80S TO LOWER 90S...DEPENDING ON
TIMING OF THE SHORTWAVES AND ANY SHOWERS AND STORM ASSOCIATED WITH
THEM. 850MB TEMPERATURE STANDARDIZED ANOMALIES HOVER AROUND PLUS 2
THIS WEEKEND THROUGH EARLY NEXT WEEK SO WILL HAVE TO KEEP A CLOSE
WATCH ON THE POTENTIAL FOR HEAT HEADLINES WITH THE POSSIBILITY OF
SEEING NEAR RECORD HEAT FOR THESE DATES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1215 PM CDT SUN AUG 25 2013
BREEZY SOUTHWEST WINDS TO CONTINUE THROUGH EARLY THIS EVENING
BEFORE SUBSIDING AFTER SUNSET...OTHERWISE VFR CONDITIONS WILL
PREVAIL. ATTENTION THEN TURNS TO INCREASING CONFIDENCE OF A
THUNDERSTORM COMPLEX DEVELOPING ACROSS CENTRAL MN INTO NORTHWEST
WI THIS EVENING...THEN MOVING SOUTHEAST THROUGH THE AREA
OVERNIGHT/EARLY MONDAY MORNING. QUESTION WILL BE HOW FAR SOUTH
THIS COMPLEX OF STORMS GETS/POTENTIAL OF AFFECTING TAF SITES/ BEFORE
SHUNTING EAST MONDAY MORNING. FOR NOW...HAVE CONTINUED A VCTS
MENTION AT KRST/KLSE TAF SITES IN THE 09-15Z TIME FRAME. MODEL
SOUNDINGS SHOWING THAT THIS CONVECTION/STORMS WILL BE ELEVATED IN
NATURE WITH CLOUD BASES GENERALLY AOA 8KFT. LOOKING FOR THIS
COMPLEX OF STORMS TO SHIFT EAST OF THE AREA AFTER 15Z WITH VFR
CONDITIONS EXPECTED.
&&
.CLIMATE...
ISSUED AT 346 PM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ079-
086>088-094>096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...DAS
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1215 PM CDT SUN AUG 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES TODAY AND THUNDERSTORM
POTENTIAL TONIGHT.
...CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
ALONG THE WEST COAST OF NORTH AMERICA AND STRONG SUBTROPICAL
RIDGING ENCOMPASSING KANSAS AND MISSOURI. AROUND THE RIDGING...
MONSOONAL MOISTURE AND SHORTWAVES WERE EMANATING FROM BAJA
CALIFORNIA / WHERE TROPICAL DEPRESSION IVO WAS LOCATED / NORTH-
NORTHEAST INTO THE DAKOTAS. ONE SUCH MONSOONAL SHORTWAVE...ENHANCED
BY CONVECTION...WAS TRACKING ACROSS NORTHERN ONTARIO. THE
CONVECTION WITH THIS SHORTWAVE EXTENDS SOUTH INTO NORTHERN MN AND
UPPER MI...BEING FED WITH MOISTURE BY A 35-50KT 850MB JET SEEN ON
VWP AND PROFILER DATA EXTENDING FROM NEBRASKA INTO WESTERN LAKE
SUPERIOR. EVEN A FEW STRAY SHOWERS EXTEND SOUTH INTO TREMPEALEAU
COUNTY. REGARDING THE MOISTURE...GOES DERIVED PRECIPITABLE WATER
IMAGERY SHOWED VALUES OF 1.5-2 INCHES ACROSS MUCH OF THE UPPER
MIDWEST. THE CONVECTION IS ALSO RIDING ALONG THE EDGE OF A HOT
AIRMASS ENCOMPASSING THE CENTRAL AND NORTHERN PLAINS AS WELL AS
THE UPPER MIDWEST. RAP SHOWED 700MB TEMPS OF 12C OR HIGHER FROM
DULUTH MN BACK INTO WESTERN NEBRASKA. MEANWHILE...DOWN AT
850MB...READINGS RANGED FROM 20-22C OVER THE FORECAST AREA TO
26-28C IN SOUTH DAKOTA. THE WARM AIRMASS EXTENDS DOWN TO THE
SURFACE...WHERE OVER THE FORECAST AREA...A SOUTH BREEZE AND
DEWPOINTS IN THE UPPER 60S TO LOW 70S HAS KEPT TEMPS AT OR ABOVE
70F. ALSO OF NOTE AT THE SURFACE IS A LOW PRESSURE TROUGH FROM
INTERNATIONAL FALLS MN SOUTHWEST TO PHILLIP SOUTH DAKOTA.
...HAZARDS...
1. HEAT ADVISORY REMAINS ON TRACK FOR TODAY AND IN FACT HEAT
INDICES MAY END UP HIGHER.
2. POTENTIAL CONVECTION TONIGHT COULD POSE A SEVERE RISK...
PRIMARILY NORTH OF I-90. ISOLATED LARGE HAIL AND DAMAGING WINDS
MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
25.00Z MODELS ARE IN VERY GOOD AGREEMENT SHOWING THAT A WEAK
500MB RIDGE AXIS PRESENT ACROSS MN WILL FLATTEN OUT TODAY...THEN
REBUILDS OVER THE DAKOTAS AHEAD OF A MORE DYNAMIC SHORTWAVE
LIFTING OUT OF ARIZONA INTO WYOMING. WITHIN THE 500MB
FLOW...MODELS SUGGEST A MONSOONAL SHORTWAVE SOMEWHERE IN NORTHWEST
COLORADO OR EASTERN WYOMING CURRENTLY TO CROSS CENTRAL MN AND
NORTHERN WI TONIGHT.
...DETAILS...
THE FLATTENING OF THE 500MB FLOW TODAY WILL HELP TO SPREAD MORE OF
THE WARMTH SEEN OVER SOUTH DAKOTA EASTWARD. 850MB TEMPS CLIMB TO
21-23C WHILE DOWN AT 925MB THEY JUMP TO 26-28C. MIXING TO THE 850MB
TEMPS WHICH SEEMS QUITE REASONABLE GIVEN THAT WE SHOULD HAVE FULL
SUN AND A BREEZY SOUTHWEST WIND YIELDS HIGHS IN THE LOW TO MID 90S.
NOTICED THAT THE RAP IS EVEN WARMER...SUGGESTING HIGHS OF 95-100.
THE REASON IS DUE TO SUPERADIABATIC EFFECTS...WHICH LOOK A BIT
OVERDONE. WITH DEWPOINTS HOVERING IN THE UPPER 60S TO LOWER 70S ALL
DAY...HEAT INDICES SHOULD TOP OUT BETWEEN 97-102.
NOW THE BIGGER QUESTION IS CONVECTION CHANCES FOR LATE THIS
AFTERNOON INTO TONIGHT. A COUPLE OF SCENARIOS EXIST...
1. THE 25.00Z NAM QUICKLY ERODES THE CAP BETWEEN 18-21Z FROM DULUTH
INTO WESTERN UPPER MI...PERHAPS CAUSED BY AN OUTFLOW BOUNDARY
EMANATING FROM CURRENT CONVECTION TRACKING ACROSS LAKE SUPERIOR.
THIS CONVECTION THEN DIVES SOUTH INTO NORTHERN SECTIONS OF THE
FORECAST AREA DURING THE EVENING INTO THE 850MB MOISTURE TRANSPORT
AXIS...FOLLOWING CORFIDI VECTORS. THE CONVECTION EVENTUALLY WANES
AFTER MIDNIGHT AS THE CAP RESTRENGTHENS. CONCERNED THAT THE NAM...IN
PARTICULAR ITS BMJ CONVECTIVE SCHEME...MAY BE ERODING THE CAP TOO
QUICKLY.
2. THE 25.00Z GFS...24.12Z ECMWF...THE BULK OF THE 25.03Z SREF
MEMBERS AND 25.00Z HIRES-ARW GENERALLY WAIT TO BREAK OUT CONVECTION
UNTIL AFTER 00Z ACROSS CENTRAL MN INTO NORTHERN WI...WHICH THEN
DROPS SOUTH MORE INTO THE FORECAST AREA AFTER 06Z. AGAIN THE
CONVECTION DIVES INTO THE 850MB MOISTURE TRANSPORT AXIS...FOLLOWING
CORFIDI VECTORS. ADDITIONALLY...THESE MODELS SUGGEST THAT SHORTWAVE
COMING OUT OF NORTHWEST COLORADO AND EASTERN WYOMING COULD BE AN
ENHANCING PLAYER.
3. THE 24.12Z HIRES-ARW...25.00Z CANADIAN...UKMET AND ECMWF HAVE THE
ONLY CONVECTION OCCURRING ACROSS NORTHERN WI AND UPPER MI TONIGHT...
ON THE NOSE OF THE 850MB MOISTURE TRANSPORT. THEY SUGGESTS THE CAP
HOLDS FOR LATE THIS AFTERNOON THROUGH TONIGHT...DIFFERENT FROM
EITHER OF THE ABOVE 2 SCENARIOS.
WHICH OF THE ABOVE 3 SCENARIOS PANS OUT BASICALLY DEPENDS ON THE
STRENGTH OF THE CAP. FOR NOW LEANED TOWARDS SCENARIO NUMBER 2 AS IT
HAS THE STRONGEST CONSENSUS...THOUGH CANNOT COMPLETELY RULE OUT
NUMBER 3. THEREFORE...HAVE LIMITED PRECIPITATION CHANCES TO NO MORE
THAN 50. THE SECOND SCENARIO ALSO POSES A MARGINAL SEVERE RISK NORTH
OF I-90...GIVEN 0-6 KM SHEAR VALUES REACHING 25-30 KT AND STRONG
INSTABILITY. MULTICELLS SEEM TO BE THE MOST LIKELY STORM MODE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN AUG 25 2013
...HAZARDS...
1. HEAT. HEAT ADVISORIES CONTINUE TO LOOK SOLID FOR MONDAY AND
TUESDAY...AND THERE IS EVEN SOME CONCERN WE MAY HAVE TO UPGRADE
PORTIONS OF THE AREA TO EXCESSIVE HEAT WARNING ON TUESDAY. THE
ADVISORY MAY ALSO HAVE TO BE EXTENDED INTO WEDNESDAY SOUTH OF
I-90. ANOTHER ROUND OF HEAT HAZARDS ARE POSSIBLE FOR LABOR DAY
WEEKEND.
2. STORMS. POTENTIAL FOR SOME SEVERE WEATHER MONDAY NIGHT IF THE
25.00Z NAM/GFS ARE CORRECT WITH ANOTHER THUNDERSTORM COMPLEX MOVING
THROUGH. ISOLATED LARGE HAIL AND DAMAGING WINDS MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
THE SUBTROPICAL HIGH CENTERED OVER KANSAS AND MISSOURI REMAINS
PROGGED TO RETROGRADE WESTWARD TO SIT MOSTLY OVER KANSAS FOR
TUESDAY THROUGH THURSDAY. THIS RETROGRESSION IS CAUSED BY DEEPER
TROUGHING GRADUALLY FORMING OVER NEW ENGLAND. WHAT HAS BEEN
PROBLEMATIC IS AFTER THURSDAY. 24.12Z ECMWF KEPT A NORTHWEST FLOW
PATTERN GOING OVER THE FORECAST AREA FOR FRIDAY AND SATURDAY AS
THE TROUGH PERSISTS IN NEW ENGLAND. HOWEVER...THE NEW 25.00Z ECMWF
GOES ALONG WITH THE 25.00Z GFS TO ALLOW THE SUBTROPICAL HIGH AND
ASSOCIATED RIDGING TO SHIFT EAST QUICKER. THIS MEANS THAT HEAT
ISSUES ARE MORE LIKELY FOR LABOR DAY WEEKEND.
...PRECIPITATION DETAILS...
ALL INDICATIONS ARE THAT SHOULD CONVECTION FROM TONIGHT SHOULD
WEAKEN MONDAY MORNING DUE TO DIMINISHING MOISTURE TRANSPORT.
MAINTAINED 20-40 PERCENT CHANCES MAINLY ACROSS WI FOR THE
CONVECTION. THESE CHANCES SHIFT TO NORTH OF I-94 FOR THE AFTERNOON
WHERE THE REMNANT OUTFLOW/WARM FRONTAL BOUNDARY MAY SERVE AS A
TRIGGER FOR RENEWED CONVECTIVE DEVELOPMENT. OF COURSE...SHOULD THE
UKMET/CANADIAN/ECMWF PAN OUT...MONDAY WILL BE DRY. 20-40 PERCENT
CHANCES CONTINUE MONDAY NIGHT AND TUESDAY...GENERALLY ALONG AND
NORTH OF I-94...WHERE ANOTHER THUNDERSTORM COMPLEX MAY SLIDE
ACROSS AS INDICATED BY THE 25.00Z NAM/GFS. THESE STORMS WILL ALSO
HAVE THAT STRONGER SHORTWAVE LIFTING OUT OF WYOMING AT 12Z
MONDAY...HEADING INTO CENTRAL/NORTHERN MN BY 12Z TUESDAY FORCING
IT. NOTE THAT THE 25.00Z ECMWF/CANADIAN/UKMET ARE FARTHER NORTH
WITH THIS COMPLEX...SO MONDAY NIGHT AND TUESDAY COULD BE DRY AS
WELL...THUS THE 20-40 PERCENT CHANCES. SIMILAR TO TONIGHT...SHOULD
THE COMPLEX ROLL THROUGH...CANNOT RULE OUT SOME SEVERE WEATHER
POTENTIAL WITH THEM. COLD FRONTAL PASSAGE OCCURS TUESDAY NIGHT BUT
INDICATIONS ARE THAT THE AIRMASS MAY BE TOO CAPPED TO ALLOW ANY
CONVECTION WITH IT. IN FACT MOST MODELS ARE DRY. THEREFORE REDUCED
CHANCES SUCH THAT ONLY A 20 PERCENT CHANCE IS LEFT CLOSER TOWARDS
CENTRAL WI TO BLEND WITH NEIGHBORING OFFICES. WEDNESDAY STILL
LOOKS DRY WITH THE FRONT SOUTH OF THE AREA. SMALL CHANCES OF
STORMS RETURN THURSDAY THROUGH FRIDAY AS THE FRONT COMES BACK AS A
WARM FRONT. DRY CONDITIONS ARE ANTICIPATED SATURDAY WITH THE AREA
IN THE WARM SECTOR.
...TEMPERATURE DETAILS...
ON MONDAY...EVEN IF THERE ARE STORMS DISSIPATING IN THE MORNING
AND NEW ONES FIRE LATER IN THE DAY...ALL INDICATIONS ARE THAT
THERE WILL STILL BE PLENTY OF TIME FOR TEMPERATURES TO RECOVER.
925 AND 850MB TEMPS ARE ABOUT 1C HIGHER COMPARED TO TODAY...THUS
ANTICIPATING HIGHS 1-2 F HIGHER. UPPER 60S/LOW 70S DEWPOINTS STILL
SEEM REASONABLE RESULTING IN 100-105 HEAT INDICES.
TUESDAY STILL LOOKS LIKE THE HOTTEST DAY AS 925-850MB WINDS VEER
MORE WESTERLY...REALLY ADVECTING THE CORE OF THE HOT AIR OVER SOUTH
DAKOTA AND NEBRASKA AT US. 925MB TEMPS CLIMB TO AROUND 30C OVER MOST
OF THE FORECAST AREA WHICH IS USUALLY A GOOD CORRELATION FOR 100F
TEMPS. RAISED HIGHS A LITTLE MORE AND FURTHER INCREASES MAY BE
REQUIRED. DEWPOINTS LOOK LIKE THEY SHOULD HOLD THROUGH
EVAPOTRANSPORATION IN THE UPPER 60S/LOW 70S...WHICH MEANS HEAT
INDICES COULD CROSS THE 105 WARNING THRESHOLD IN SOME SPOTS.
WEDNESDAY IS BECOMING A BIT MORE CONCERNING AS THE 25.00Z ECMWF/GFS
ARE NOT AS QUICK BRINGING IN THE COOLER AIR BEHIND THE COLD FRONT.
925MB TEMPS STILL GET UP TO 28C OR HIGHER. THUS...INCREASED HIGHS A
FEW DEGREES TO SHOW UPPER 80S TO LOW 90S. THESE MAY NEED TO BE
INCREASED MORE...WHICH WOULD PROMPT AN EXTENSION OF THE HEAT
ADVISORY ANOTHER DAY.
THURSDAY AND FRIDAY WILL BE THE COOLEST DAYS...RELATIVELY SPEAKING
AS 925MB TEMPS ONLY COOL TO 25-27C. THEN IF THE NEW 25.00Z ECMWF AND
GFS ARE CORRECT...THESE CLIMB RIGHT BACK UP TO EVEN WARMER THAN THE
CURRENT HEAT STRETCH...TO 30-32C FOR SATURDAY AND SUNDAY. IF THIS
OCCURS...WE COULD EASILY BE LOOKING AT 100 DEGREE HEAT NEXT WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1215 PM CDT SUN AUG 25 2013
BREEZY SOUTHWEST WINDS TO CONTINUE THROUGH EARLY THIS EVENING
BEFORE SUBSIDING AFTER SUNSET...OTHERWISE VFR CONDITIONS WILL
PREVAIL. ATTENTION THEN TURNS TO INCREASING CONFIDENCE OF A
THUNDERSTORM COMPLEX DEVELOPING ACROSS CENTRAL MN INTO NORTHWEST
WI THIS EVENING...THEN MOVING SOUTHEAST THROUGH THE AREA
OVERNIGHT/EARLY MONDAY MORNING. QUESTION WILL BE HOW FAR SOUTH
THIS COMPLEX OF STORMS GETS/POTENTIAL OF AFFECTING TAF SITES/ BEFORE
SHUNTING EAST MONDAY MORNING. FOR NOW...HAVE CONTINUED A VCTS
MENTION AT KRST/KLSE TAF SITES IN THE 09-15Z TIME FRAME. MODEL
SOUNDINGS SHOWING THAT THIS CONVECTION/STORMS WILL BE ELEVATED IN
NATURE WITH CLOUD BASES GENERALLY AOA 8KFT. LOOKING FOR THIS
COMPLEX OF STORMS TO SHIFT EAST OF THE AREA AFTER 15Z WITH VFR
CONDITIONS EXPECTED.
&&
.CLIMATE...
ISSUED AT 330 AM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ079-
086>088-094>096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1147 AM CDT SUN AUG 25 2013
UPDATED UPDATE/AVIATION PORTION FOR 18Z TAF ISSUANCE
.UPDATE...
ISSUED AT 1129 AM CDT SUN AUG 25 2013
LATEST MESO ANALYSIS INDICATED THINGS WERE SETTING UP ACROSS
NORTHERN WISCONSIN AND UPPER MICHIGAN LATE THIS MORNING. SURFACE
BASED CAPES WERE ALREADY BETWEEN 2000 AND 3000 J/KG...DCAPES WERE
AT 1000/1500 J/KG AND LIFTED INDICES OF -4 TO -6 C AND 0-6KM SHEAR
OF 30 TO 35 KNOTS. ALSO...IMPRESSIVE POOLING OF DEW POINTS AROUND
850MB...ALONG WITH MOISTURE CONVERGENCE NOTED ON THE SPC MESOANALYSIS
PAGE.
INCREASING LOW LEVEL JET LATER THIS AFTERNOON ALONG WITH ALL THE
HEAT AND HUMIDITY WILL PROVIDE AMPLE SUPPORT FOR STRONG TO SEVERE
THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON OR EARLY THIS EVENING
ACROSS NORTHERN WISCONSIN. THE STORMS WILL GRADUALLY SAG SOUTHWARD
ACROSS THE REMAINDER OF THE AREA DURING THE EVENING INTO EARLY
MONDAY MORNING. MODIFIED SOUNDINGS AT RHINELANDER INDICATED 3000
TO 3500 J/KG OF CAPE...WET BULB HEIGHTS NEAR TWELVE THOUSAND FEET
AND WINDEX VALUES OF 45 TO 55 KNOTS. DESPITE BEING LATER IN THE
EVENING OR EARLY MONDAY MORNING...ENOUGH 0-6 KM SHEAR SUPPORT THE
POTENTIAL FOR SOME DAMAGING WINDS OR LARGE HAIL ACROSS THE FOX
VALLEY AND LAKESHORE REGION. ALSO...TORRENTIAL RAIN WILL BE ACCOMPANIED
BY SOME OF THE STORMS THAT COULD PRODUCE LOCALIZED FLOODING.
LOOKING AHEAD TO MONDAY...CONVECTION TONIGHT COULD HAVE A BIG IMPACT
ON MAXIMUM TEMPERATURES WHICH IS PROBLEMATIC FOR HEAT HEADLINES. WILL
NEED TO ASSESS THIS FOR THE AFTERNOON PACKAGE.
.SHORT TERM...TODAY...TONIGHT...AND MONDAY
ISSUED AT 500 AM CDT SUN AUG 25 2013
UPPER RIDGE CONTINUES TO FLATTEN OVER THE WESTERN GREAT LAKES AS
SHORT WAVE IMPULSE MOVES EAST ACROSS NORTHERN LAKE SUPERIOR THIS
MORNING. FOR THE MOST PART...SHORT RANGE MODELS INCLUDING THE HRRR
AND RAP DID A RATHER LOUSY JOB HANDLING STRONGER CONVECTION NORTH
OF WISCONSIN...AS WELL AS LIGHTER SCATTERED SHOWER ACTIVITY MOVING
ACROSS CENTRAL AND NORTHERN WISCONSIN EARLY THIS MORNING. SCATTERED
SHOWER AND ISOLATED THUNDERSHOWER ACTIVITY OVER THE FORECAST AREA
APPEARS TO BE ASSOCIATED WITH VERY WEAK UPPER-LEVEL IMPULSE...MODEST
WAA AND NEAR EASTERN EDGE OF ROBUST CAP EXTENDING FROM CENTRAL
MINNESOTA INTO NORTHWEST WISCONSIN. THIS ACTIVITY WILL CONTINUE TO
PUSH ACROSS THE FORECAST AREA THIS MORNING AND SHOULD REMAIN
SCATTERED AND LIGHT IN INTENSITY. ACTIVITY EXPECTED TO BE EAST OF
THE FORECAST AREA BY AROUND 15Z.
LOOKING FARTHER UPSTREAM...MORE SCATTERED THUNDERSTORM ACTIVITY
HAS DEVELOPED OVER WESTERN MINNESOTA AHEAD OF FRONTAL BOUNDARY
OVER THE DAKOTAS. MAJORITY OF THE GUIDANCE SUGGESTS THAT THIS
ACTIVITY WILL BEGIN TO SINK MORE SSE ACROSS CENTRAL MINNESOTA
LATER THIS MORNING AND GRADUALLY WEAKEN AS IT CONTINUES TO
PROPAGATE AWAY FROM FRONTAL BOUNDARY. HOWEVER LATEST RADAR TRENDS
SHOWING MORE OF AN EASTWARD MOVEMENT AND IF THIS ACTIVITY HOLDS
TOGETHER IT MAY IMPACT THE NORTHWEST PORTION OF THE FORECAST AREA
LATE THIS MORNING. WILL NEED TO KEEP AN EYE ON THIS ACTIVITY THIS
MORNING. FOR NOW WILL STICK TO CURRENT THINKING THAT THIS
ACTIVITY SHOULD WEAKEN BEFORE IT REACHES THE FORECAST AREA. THUS
IT APPEARS THAT FORECAST AREA STILL ON TRACK FOR A HOT AND
INCREASINGLY HUMID DAY. DID NOT MAKE ANY CHANGES TO PREVIOUS MAX
TEMPERATURE FORECAST FOR TODAY THUS STILL EXPECT TEMPS TO REACH
THE 90-95 DEGREE RANGE OVER THE WESTERN PORTION OF THE FORECAST
AREA WITH READINGS NEAR 90 ACROSS THE NORTH WOODS. DID ADJUST
DEW POINTS DOWN A DEGREE OR TWO THIS AFTERNOON WITH ANTICIPATED
AFTERNOON MIXING. THUS HEAT INDICES WILL BE GENERALLY IN 95 TO 100
DEGREE RANGE WITH HIGHEST VALUES OVER THE WESTERN PORTION OF THE
FORECAST AREA THIS AFTERNOON.
FOR THIS EVENING AND TONIGHT...QUESTION THEN BECOMES WHEN AND
WHERE THUNDERSTORM ACTIVITY WILL FIRE AS SHORTWAVE IMPULSE HEADS
EAST TOWARD THE WESTERN GREAT LAKES AND FRONTAL BOUNDARY
APPROACHES. ALTHOUGH THERE HAS BEEN A VARIETY OF SOLUTIONS AS TO
HOW THE SCENARIO WILL PLAY OUT...SEEMS THAT A WEAK CONSENSUS OF
THE GUIDANCE SUGGESTS THAT THUNDERSTORM ACTIVITY WILL DEVELOP NEAR
THE WISCONSIN-MICHIGAN BORDER...ALONG AND AHEAD OF FRONTAL
BOUNDARY FORECAST TO DRIFT SSE INTO NORTHERN WISCONSIN THIS
EVENING. THIS BOUNDARY MAY ALSO GET SOME REINFORCEMENT FROM LAKE
SUPERIOR BREEZE. THIS ACTIVITY SHOULD THEN SAG SOUTHWARD ACROSS
THE FORECAST AREA OVERNIGHT INTO MONDAY MORNING. SHOULD BE PLENTY
OF INSTABILITY OVER THE FORECAST AREA SUNDAY EVENING WITH MLCAPES
AROUND 3000 J/KG. BEST DEEP LAYER SHEAR TO SUSTAIN UPDRAFTS WILL
BE OVER THE NORTHERN HALF OF THE FORECAST AREA. SPC ADDED MOST
OF THE FORECAST AREA INTO A SLIGHT RISK FOR SEVERE LATE THIS
AFTERNOON AND INTO THE LATE EVENING HOURS WHICH SEEMS REASONABLE.
PRIMARY THREAT APPEARS TO BE DAMAGING WINDS AND PERHAPS SOME
LARGE HAIL. MODELS VARY AS TO THE TIMING THE CONVECTION WILL
FIRE...BEST GUESS IS SOMETIME IN THE 23-02Z TIME FRAME WITH
ACTIVITY MOVING SOUTH OR SOUTHEAST ACROSS THE FORECAST AREA TOWARD
MIDNIGHT. WILL ALSO NEED TO KEEP AN EYE ON A LOCALLY HEAVY
RAINFALL THREAT...ESPECIALLY IF ACTIVITY CAN TRAIN FROM WEST TO
EAST ALONG FRONTAL BOUNDARY LATER TONIGHT.
MORE UNCERTAINTY FOR MONDAY AS MODELS DIVERGE ON HOW LONG ACTIVITY
WILL PERSIST ALONG FRONTAL BOUNDARY EXPECTED TO BE LOCATED
SOMEWHERE OVER NORTHERN WISCONSIN. LOCATION OF RESIDUAL
THUNDERSTORM OUTFLOW IS ALSO A FACTOR AS TO WHERE ADDITIONAL
CONVECTION MAY FIRE AGAIN DURING THE DAY ON MONDAY. FOR NOW KEPT
BROAD BRUSH CHANCE POPS ACROSS THE ENTIRE FORECAST AREA. MAX TEMPS
ON MONDAY WILL BE DEPENDENT ON RESIDUAL CLOUD
COVER...PRECIPITATION AND LOCATION OF FRONTAL BOUNDARY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
ISSUED AT 501 AM CDT SUN AUG 25 2013
WHILE THE CNTRL CONUS UPR RDG TO REMAIN THE MAIN WEATHER FEATURE
THRU MUCH OF THE UPCOMING WEEK...ITS SLOW RETROGRESSION FROM THE
MID-MS VALLEY TO THE CNTRL HI PLAINS WL ALLOW THE MEAN FLOW TO
TURN NW BY THU AND BRING SLIGHTLY COOLER/DRIER CONDITIONS TO NE
WI. MAIN FCST EMPHASIS TO BE THRU MID-WEEK AS A FRONTAL BOUNDARY
MOVES THRU AN UNSTABLE AIR MASS AND SETS THE STAGE FOR TSTMS. A
FEW OF THESE STORMS MAY BECOME STRONG TO SEVERE WITH LOCALLY HEAVY
RAINFALL. TEMPS TO REMAIN WELL ABOVE NORMAL TIL FURTHER NOTICE...
ESPECIALLY THRU THU.
PLENTY OF QUESTIONS LINGER FOR TUE STARTING WITH WHERE (IF) MON
NGT`S CONVECTION TO BE LOCATED...WHERE THE NRN WI FRONTAL BOUNDARY
TO RESIDE...WL ADDITIONAL PCPN DEVELOP ON THE EDGE OF THE CAP AND
COULD ANY OF THESE STORMS TURN SEVERE? THE KEY APPEARS TO BE THE
MON NGT CONVECTION SINCE IF IT WERE TO DEVELOP...MORE CLOUDS AND
BRIEF STABILIZATION WOULD OCCUR. IF THIS CONVECTION STAYS TO THE
NORTH...THIS WOULD ALLOW TEMPS TO SOAR ONCE AGAIN AND ALLOW THE
ATMOSPHERE TO REALLY DESTABILIZE BY THE AFTERNOON. TO TOP ALL OF
THIS OFF...THE MDLS BRING A WEAK SFC TROF INTO WI. HARD TO FATHOM
NOT SEEING ANY PCPN MON NGT...THUS HAVE SIDED WITH MENTIONING A
HIGHER POP ON TUE ACROSS FAR NE WI WHERE THE WEAKER CAP WL EXIST.
SEVERE POTENTIAL TO BE DICTATED BY HOW WARM WE CAN GET AND WHETHER
THAT APPROACHING WEAK SFC TROF CAN GENERATE ENUF LIFT TO BREAK THE
CAP. IF THE CAP IS BROKEN...WE COULD SEE A ROUND OF STRONG TO
SEVERE STORMS WITH LARGE HAIL...DAMAGING WINDS AND TORRENTIAL
DOWNPOURS.
SHWR/TSTM THREAT WOULD CARRYOVER INTO TUE EVENING UNTIL THE SFC
TROF EXITS THE AREA AND A WEAK AREA OF HI PRES BEGINS TO BUILD
ACROSS THE UPR MS VALLEY. ONLY CHANGE TO THIS PART OF THE FCST WAS
TO FOCUS PCPN CHCS TO THE EVENING WITH A CLEARING TREND FOR THE
OVRNGT HOURS. BY THE MIDDLE OF THE WEEK...THE UPR RDG IS PROGGED
TO HAVE RETROGRADED BACK TOWARD THE CNTRL PLAINS WTH THE MEAN FLOW
OVER THE GREAT LAKES TURNING MORE NW. WEAK HI PRES TO BE SITUATED
OVER THE WRN GREAT LAKES REGION ON WED...THUS A DECENT AMOUNT OF
SUNSHINE IS ANTICIPATED. 8H TEMPS TO STILL BE AROUND +20C...SO
TEMPS WL REMAIN RATHER WARM WITH A MINOR DROP IN DEW POINTS BEHIND
THE DEPARTED SFC TROF.
THERE ARE NOW CONCERNS FOR THU`S DRY FCST AS THE MDLS ARE
INDICATING THE NEXT MID-LEVEL SHORTWAVE TROF TO BE ROUNDING THE
CNTRL CONUS UPR RDG AND DIVING SE TOWARD WI. NOT SURE AT THIS
POINT WHETHER THIS POTENTIAL CONVECTION WOULD IMPACT ALL OF NE WI
OR DIVE SE ENUF TO ONLY AFFECT CNTRL WI. AT THIS POINT...FOLLOWED
THE CONSENSUS SOLUTION WHICH BRINGS A SLIGHT CHC POP TO MUCH OF
THE FCST AREA. TEMPS FOR WED LOOK TO BE SIMILAR TO WED WITH PLENTY
OF 80S TO GO AROUND.
ANOTHER AREA OF HI PRES IS EXPECTED TO BUILD SWD FROM CANADA
DURING THE THU NGT/FRI TIME PERIOD. DO NOT CARE FOR THE MINIMAL
POP ADVERTISED BY THE CONSENSUS SOLUTION AND PREFER TO GO DRY FOR
FRI WITH TEMPS GENERALLY IN THE 80-85 DEG RANGE. RETURN FLOW THEN
SETS UP OVER THE REGION NEXT WEEKEND WHICH WL LEAD TO WARMER
TEMPS...AN UPTICK IN HUMIDITY LEVELS AND THE POSSIBILITY OF WAA-
INDUCED PCPN CHCS. ATTM...ANY PCPN APPEARS TO BE WIDELY SCT AT
BEST WITH NO FOCUSING MECHANISM PRESENT.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1127 AM CDT SUN AUG 25 2013
STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS
NORTH-CENTRAL WISCONSIN LATE THIS AFTERNOON OR EARLY THIS EVENING...
THEN SAG SOUTHWARD ACROSS THE AREA DURING THE EVENING INTO EARLY
MONDAY MORNING. SOME OF THE STRONGER STORMS COULD PRODUCE GUSTS
OVER 50 KNOTS AND HAIL OVER 1 INCH IN DIAMETER. 12Z TAFS SEEMED
TO HAVE A PRETTY GOOD HANDLE ON TIMING OF CONVECTION AND WILL MAKE
SOME MINOR ADJUSTMENTS THERE. GREATEST RISK OF SEVERE WEATHER SHOULD
BE NORTH AND WEST OF THE FOX VALLEY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........ECKBERG
SHORT TERM.....ESB
LONG TERM......KALLAS
AVIATION.......ECKBERG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
653 AM CDT SUN AUG 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES TODAY AND THUNDERSTORM
POTENTIAL TONIGHT.
...CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
ALONG THE WEST COAST OF NORTH AMERICA AND STRONG SUBTROPICAL
RIDGING ENCOMPASSING KANSAS AND MISSOURI. AROUND THE RIDGING...
MONSOONAL MOISTURE AND SHORTWAVES WERE EMANATING FROM BAJA
CALIFORNIA / WHERE TROPICAL DEPRESSION IVO WAS LOCATED / NORTH-
NORTHEAST INTO THE DAKOTAS. ONE SUCH MONSOONAL SHORTWAVE...ENHANCED
BY CONVECTION...WAS TRACKING ACROSS NORTHERN ONTARIO. THE
CONVECTION WITH THIS SHORTWAVE EXTENDS SOUTH INTO NORTHERN MN AND
UPPER MI...BEING FED WITH MOISTURE BY A 35-50KT 850MB JET SEEN ON
VWP AND PROFILER DATA EXTENDING FROM NEBRASKA INTO WESTERN LAKE
SUPERIOR. EVEN A FEW STRAY SHOWERS EXTEND SOUTH INTO TREMPEALEAU
COUNTY. REGARDING THE MOISTURE...GOES DERIVED PRECIPITABLE WATER
IMAGERY SHOWED VALUES OF 1.5-2 INCHES ACROSS MUCH OF THE UPPER
MIDWEST. THE CONVECTION IS ALSO RIDING ALONG THE EDGE OF A HOT
AIRMASS ENCOMPASSING THE CENTRAL AND NORTHERN PLAINS AS WELL AS
THE UPPER MIDWEST. RAP SHOWED 700MB TEMPS OF 12C OR HIGHER FROM
DULUTH MN BACK INTO WESTERN NEBRASKA. MEANWHILE...DOWN AT
850MB...READINGS RANGED FROM 20-22C OVER THE FORECAST AREA TO
26-28C IN SOUTH DAKOTA. THE WARM AIRMASS EXTENDS DOWN TO THE
SURFACE...WHERE OVER THE FORECAST AREA...A SOUTH BREEZE AND
DEWPOINTS IN THE UPPER 60S TO LOW 70S HAS KEPT TEMPS AT OR ABOVE
70F. ALSO OF NOTE AT THE SURFACE IS A LOW PRESSURE TROUGH FROM
INTERNATIONAL FALLS MN SOUTHWEST TO PHILLIP SOUTH DAKOTA.
...HAZARDS...
1. HEAT ADVISORY REMAINS ON TRACK FOR TODAY AND IN FACT HEAT
INDICES MAY END UP HIGHER.
2. POTENTIAL CONVECTION TONIGHT COULD POSE A SEVERE RISK...
PRIMARILY NORTH OF I-90. ISOLATED LARGE HAIL AND DAMAGING WINDS
MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
25.00Z MODELS ARE IN VERY GOOD AGREEMENT SHOWING THAT A WEAK
500MB RIDGE AXIS PRESENT ACROSS MN WILL FLATTEN OUT TODAY...THEN
REBUILDS OVER THE DAKOTAS AHEAD OF A MORE DYNAMIC SHORTWAVE
LIFTING OUT OF ARIZONA INTO WYOMING. WITHIN THE 500MB
FLOW...MODELS SUGGEST A MONSOONAL SHORTWAVE SOMEWHERE IN NORTHWEST
COLORADO OR EASTERN WYOMING CURRENTLY TO CROSS CENTRAL MN AND
NORTHERN WI TONIGHT.
...DETAILS...
THE FLATTENING OF THE 500MB FLOW TODAY WILL HELP TO SPREAD MORE OF
THE WARMTH SEEN OVER SOUTH DAKOTA EASTWARD. 850MB TEMPS CLIMB TO
21-23C WHILE DOWN AT 925MB THEY JUMP TO 26-28C. MIXING TO THE 850MB
TEMPS WHICH SEEMS QUITE REASONABLE GIVEN THAT WE SHOULD HAVE FULL
SUN AND A BREEZY SOUTHWEST WIND YIELDS HIGHS IN THE LOW TO MID 90S.
NOTICED THAT THE RAP IS EVEN WARMER...SUGGESTING HIGHS OF 95-100.
THE REASON IS DUE TO SUPERADIABATIC EFFECTS...WHICH LOOK A BIT
OVERDONE. WITH DEWPOINTS HOVERING IN THE UPPER 60S TO LOWER 70S ALL
DAY...HEAT INDICES SHOULD TOP OUT BETWEEN 97-102.
NOW THE BIGGER QUESTION IS CONVECTION CHANCES FOR LATE THIS
AFTERNOON INTO TONIGHT. A COUPLE OF SCENARIOS EXIST...
1. THE 25.00Z NAM QUICKLY ERODES THE CAP BETWEEN 18-21Z FROM DULUTH
INTO WESTERN UPPER MI...PERHAPS CAUSED BY AN OUTFLOW BOUNDARY
EMANATING FROM CURRENT CONVECTION TRACKING ACROSS LAKE SUPERIOR.
THIS CONVECTION THEN DIVES SOUTH INTO NORTHERN SECTIONS OF THE
FORECAST AREA DURING THE EVENING INTO THE 850MB MOISTURE TRANSPORT
AXIS...FOLLOWING CORFIDI VECTORS. THE CONVECTION EVENTUALLY WANES
AFTER MIDNIGHT AS THE CAP RESTRENGTHENS. CONCERNED THAT THE NAM...IN
PARTICULAR ITS BMJ CONVECTIVE SCHEME...MAY BE ERODING THE CAP TOO
QUICKLY.
2. THE 25.00Z GFS...24.12Z ECMWF...THE BULK OF THE 25.03Z SREF
MEMBERS AND 25.00Z HIRES-ARW GENERALLY WAIT TO BREAK OUT CONVECTION
UNTIL AFTER 00Z ACROSS CENTRAL MN INTO NORTHERN WI...WHICH THEN
DROPS SOUTH MORE INTO THE FORECAST AREA AFTER 06Z. AGAIN THE
CONVECTION DIVES INTO THE 850MB MOISTURE TRANSPORT AXIS...FOLLOWING
CORFIDI VECTORS. ADDITIONALLY...THESE MODELS SUGGEST THAT SHORTWAVE
COMING OUT OF NORTHWEST COLORADO AND EASTERN WYOMING COULD BE AN
ENHANCING PLAYER.
3. THE 24.12Z HIRES-ARW...25.00Z CANADIAN...UKMET AND ECMWF HAVE THE
ONLY CONVECTION OCCURRING ACROSS NORTHERN WI AND UPPER MI TONIGHT...
ON THE NOSE OF THE 850MB MOISTURE TRANSPORT. THEY SUGGESTS THE CAP
HOLDS FOR LATE THIS AFTERNOON THROUGH TONIGHT...DIFFERENT FROM
EITHER OF THE ABOVE 2 SCENARIOS.
WHICH OF THE ABOVE 3 SCENARIOS PANS OUT BASICALLY DEPENDS ON THE
STRENGTH OF THE CAP. FOR NOW LEANED TOWARDS SCENARIO NUMBER 2 AS IT
HAS THE STRONGEST CONSENSUS...THOUGH CANNOT COMPLETELY RULE OUT
NUMBER 3. THEREFORE...HAVE LIMITED PRECIPITATION CHANCES TO NO MORE
THAN 50. THE SECOND SCENARIO ALSO POSES A MARGINAL SEVERE RISK NORTH
OF I-90...GIVEN 0-6 KM SHEAR VALUES REACHING 25-30 KT AND STRONG
INSTABILITY. MULTICELLS SEEM TO BE THE MOST LIKELY STORM MODE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN AUG 25 2013
...HAZARDS...
1. HEAT. HEAT ADVISORIES CONTINUE TO LOOK SOLID FOR MONDAY AND
TUESDAY...AND THERE IS EVEN SOME CONCERN WE MAY HAVE TO UPGRADE
PORTIONS OF THE AREA TO EXCESSIVE HEAT WARNING ON TUESDAY. THE
ADVISORY MAY ALSO HAVE TO BE EXTENDED INTO WEDNESDAY SOUTH OF
I-90. ANOTHER ROUND OF HEAT HAZARDS ARE POSSIBLE FOR LABOR DAY
WEEKEND.
2. STORMS. POTENTIAL FOR SOME SEVERE WEATHER MONDAY NIGHT IF THE
25.00Z NAM/GFS ARE CORRECT WITH ANOTHER THUNDERSTORM COMPLEX MOVING
THROUGH. ISOLATED LARGE HAIL AND DAMAGING WINDS MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
THE SUBTROPICAL HIGH CENTERED OVER KANSAS AND MISSOURI REMAINS
PROGGED TO RETROGRADE WESTWARD TO SIT MOSTLY OVER KANSAS FOR
TUESDAY THROUGH THURSDAY. THIS RETROGRESSION IS CAUSED BY DEEPER
TROUGHING GRADUALLY FORMING OVER NEW ENGLAND. WHAT HAS BEEN
PROBLEMATIC IS AFTER THURSDAY. 24.12Z ECMWF KEPT A NORTHWEST FLOW
PATTERN GOING OVER THE FORECAST AREA FOR FRIDAY AND SATURDAY AS
THE TROUGH PERSISTS IN NEW ENGLAND. HOWEVER...THE NEW 25.00Z ECMWF
GOES ALONG WITH THE 25.00Z GFS TO ALLOW THE SUBTROPICAL HIGH AND
ASSOCIATED RIDGING TO SHIFT EAST QUICKER. THIS MEANS THAT HEAT
ISSUES ARE MORE LIKELY FOR LABOR DAY WEEKEND.
...PRECIPITATION DETAILS...
ALL INDICATIONS ARE THAT SHOULD CONVECTION FROM TONIGHT SHOULD
WEAKEN MONDAY MORNING DUE TO DIMINISHING MOISTURE TRANSPORT.
MAINTAINED 20-40 PERCENT CHANCES MAINLY ACROSS WI FOR THE
CONVECTION. THESE CHANCES SHIFT TO NORTH OF I-94 FOR THE AFTERNOON
WHERE THE REMNANT OUTFLOW/WARM FRONTAL BOUNDARY MAY SERVE AS A
TRIGGER FOR RENEWED CONVECTIVE DEVELOPMENT. OF COURSE...SHOULD THE
UKMET/CANADIAN/ECMWF PAN OUT...MONDAY WILL BE DRY. 20-40 PERCENT
CHANCES CONTINUE MONDAY NIGHT AND TUESDAY...GENERALLY ALONG AND
NORTH OF I-94...WHERE ANOTHER THUNDERSTORM COMPLEX MAY SLIDE
ACROSS AS INDICATED BY THE 25.00Z NAM/GFS. THESE STORMS WILL ALSO
HAVE THAT STRONGER SHORTWAVE LIFTING OUT OF WYOMING AT 12Z
MONDAY...HEADING INTO CENTRAL/NORTHERN MN BY 12Z TUESDAY FORCING
IT. NOTE THAT THE 25.00Z ECMWF/CANADIAN/UKMET ARE FARTHER NORTH
WITH THIS COMPLEX...SO MONDAY NIGHT AND TUESDAY COULD BE DRY AS
WELL...THUS THE 20-40 PERCENT CHANCES. SIMILAR TO TONIGHT...SHOULD
THE COMPLEX ROLL THROUGH...CANNOT RULE OUT SOME SEVERE WEATHER
POTENTIAL WITH THEM. COLD FRONTAL PASSAGE OCCURS TUESDAY NIGHT BUT
INDICATIONS ARE THAT THE AIRMASS MAY BE TOO CAPPED TO ALLOW ANY
CONVECTION WITH IT. IN FACT MOST MODELS ARE DRY. THEREFORE REDUCED
CHANCES SUCH THAT ONLY A 20 PERCENT CHANCE IS LEFT CLOSER TOWARDS
CENTRAL WI TO BLEND WITH NEIGHBORING OFFICES. WEDNESDAY STILL
LOOKS DRY WITH THE FRONT SOUTH OF THE AREA. SMALL CHANCES OF
STORMS RETURN THURSDAY THROUGH FRIDAY AS THE FRONT COMES BACK AS A
WARM FRONT. DRY CONDITIONS ARE ANTICIPATED SATURDAY WITH THE AREA
IN THE WARM SECTOR.
...TEMPERATURE DETAILS...
ON MONDAY...EVEN IF THERE ARE STORMS DISSIPATING IN THE MORNING
AND NEW ONES FIRE LATER IN THE DAY...ALL INDICATIONS ARE THAT
THERE WILL STILL BE PLENTY OF TIME FOR TEMPERATURES TO RECOVER.
925 AND 850MB TEMPS ARE ABOUT 1C HIGHER COMPARED TO TODAY...THUS
ANTICIPATING HIGHS 1-2 F HIGHER. UPPER 60S/LOW 70S DEWPOINTS STILL
SEEM REASONABLE RESULTING IN 100-105 HEAT INDICES.
TUESDAY STILL LOOKS LIKE THE HOTTEST DAY AS 925-850MB WINDS VEER
MORE WESTERLY...REALLY ADVECTING THE CORE OF THE HOT AIR OVER SOUTH
DAKOTA AND NEBRASKA AT US. 925MB TEMPS CLIMB TO AROUND 30C OVER MOST
OF THE FORECAST AREA WHICH IS USUALLY A GOOD CORRELATION FOR 100F
TEMPS. RAISED HIGHS A LITTLE MORE AND FURTHER INCREASES MAY BE
REQUIRED. DEWPOINTS LOOK LIKE THEY SHOULD HOLD THROUGH
EVAPOTRANSPORATION IN THE UPPER 60S/LOW 70S...WHICH MEANS HEAT
INDICES COULD CROSS THE 105 WARNING THRESHOLD IN SOME SPOTS.
WEDNESDAY IS BECOMING A BIT MORE CONCERNING AS THE 25.00Z ECMWF/GFS
ARE NOT AS QUICK BRINGING IN THE COOLER AIR BEHIND THE COLD FRONT.
925MB TEMPS STILL GET UP TO 28C OR HIGHER. THUS...INCREASED HIGHS A
FEW DEGREES TO SHOW UPPER 80S TO LOW 90S. THESE MAY NEED TO BE
INCREASED MORE...WHICH WOULD PROMPT AN EXTENSION OF THE HEAT
ADVISORY ANOTHER DAY.
THURSDAY AND FRIDAY WILL BE THE COOLEST DAYS...RELATIVELY SPEAKING
AS 925MB TEMPS ONLY COOL TO 25-27C. THEN IF THE NEW 25.00Z ECMWF AND
GFS ARE CORRECT...THESE CLIMB RIGHT BACK UP TO EVEN WARMER THAN THE
CURRENT HEAT STRETCH...TO 30-32C FOR SATURDAY AND SUNDAY. IF THIS
OCCURS...WE COULD EASILY BE LOOKING AT 100 DEGREE HEAT NEXT WEEKEND.
&&
.AVIATION...THROUGH TONIGHT
ISSUED AT 650 AM CDT SUN AUG 25 2013
THE LOW LEVEL WIND SHEAR AT KLSE WILL DISSIPATE BY 25.14Z AS
DIURNAL MIXING OCCURS AND NOCTURNAL JET WEAKENS. WITH WINDS
ALREADY GUSTING INTO THE 25 KNOT RANGE AT KRST...TOOK THE LOW
LEVEL WIND SHEER OUT OF THE TAF AT 12Z.
FROM 25.14Z THROUGH 26.02Z...THE SOUTHWEST WINDS WILL GUST INTO
THE 20 TO 30 KNOT RANGE.
FOR LATE TONIGHT...THE MAIN QUESTION IS WHETHER A THUNDERSTORM
COMPLEX WILL MOVE SOUTH TO THE INTERSTATE 90 CORRIDOR. BOTH THE
NAM AND GFS SUGGEST THAT THIS WILL BE POSSIBILITY. MEANWHILE THE
GEM AND ECMWF SUGGEST THAT IT WILL STAY NORTH OF THE AREA. WITH
THIS UNCERTAINTY JUST ADDED A VCTS AFTER 26.09Z AT BOTH TAF SITES.
IF THESE STORMS DO MOVE INTO THE AREA...THERE WILL BE A
POSSIBILITY THAT THEY COULD PRODUCE WIND DAMAGE AND LARGE HAIL.
&&
.CLIMATE...
ISSUED AT 330 AM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ017-029-032>034-041>044-053>055-061.
MN...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-086>088-094>096.
IA...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...AJ
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND MONDAY
ISSUED AT 500 AM CDT SUN AUG 25 2013
UPPER RIDGE CONTINUES TO FLATTEN OVER THE WESTERN GREAT LAKES AS
SHORT WAVE IMPULSE MOVES EAST ACROSS NORTHERN LAKE SUPERIOR THIS
MORNING. FOR THE MOST PART...SHORT RANGE MODELS INCLUDING THE HRRR
AND RAP DID A RATHER LOUSY JOB HANDLING STRONGER CONVECTION NORTH
OF WISCONSIN...AS WELL AS LIGHTER SCATTERED SHOWER ACTIVITY MOVING
ACROSS CENTRAL AND NORTHERN WISCONSIN EARLY THIS MORNING. SCATTERED
SHOWER AND ISOLATED THUNDERSHOWER ACTIVITY OVER THE FORECAST AREA
APPEARS TO BE ASSOCIATED WITH VERY WEAK UPPER-LEVEL IMPULSE...MODEST
WAA AND NEAR EASTERN EDGE OF ROBUST CAP EXTENDING FROM CENTRAL
MINNESOTA INTO NORTHWEST WISCONSIN. THIS ACTIVITY WILL CONTINUE TO
PUSH ACROSS THE FORECAST AREA THIS MORNING AND SHOULD REMAIN
SCATTERED AND LIGHT IN INTENSITY. ACTIVITY EXPECTED TO BE EAST OF
THE FORECAST AREA BY AROUND 15Z.
LOOKING FARTHER UPSTREAM...MORE SCATTERED THUNDERSTORM ACTIVITY
HAS DEVELOPED OVER WESTERN MINNESOTA AHEAD OF FRONTAL BOUNDARY
OVER THE DAKOTAS. MAJORITY OF THE GUIDANCE SUGGESTS THAT THIS
ACTIVITY WILL BEGIN TO SINK MORE SSE ACROSS CENTRAL MINNESOTA
LATER THIS MORNING AND GRADUALLY WEAKEN AS IT CONTINUES TO
PROPAGATE AWAY FROM FRONTAL BOUNDARY. HOWEVER LATEST RADAR TRENDS
SHOWING MORE OF AN EASTWARD MOVEMENT AND IF THIS ACTIVITY HOLDS
TOGETHER IT MAY IMPACT THE NORTHWEST PORTION OF THE FORECAST AREA
LATE THIS MORNING. WILL NEED TO KEEP AN EYE ON THIS ACTIVITY THIS
MORNING. FOR NOW WILL STICK TO CURRENT THINKING THAT THIS
ACTIVITY SHOULD WEAKEN BEFORE IT REACHES THE FORECAST AREA. THUS
IT APPEARS THAT FORECAST AREA STILL ON TRACK FOR A HOT AND
INCREASINGLY HUMID DAY. DID NOT MAKE ANY CHANGES TO PREVIOUS MAX
TEMPERATURE FORECAST FOR TODAY THUS STILL EXPECT TEMPS TO REACH
THE 90-95 DEGREE RANGE OVER THE WESTERN PORTION OF THE FORECAST
AREA WITH READINGS NEAR 90 ACROSS THE NORTHWOODS. DID ADJUST
DEWPOINTS DOWN A DEGREE OR TWO THIS AFTERNOON WITH ANTICIPATED
AFTERNOON MIXING. THUS HEAT INDICES WILL BE GENERALLY IN 95 TO 100
DEGREE RANGE WITH HIGHEST VALUES OVER THE WESTERN PORTION OF THE
FORECAST AREA THIS AFTERNOON.
FOR THIS EVENING AND TONIGHT...QUESTION THEN BECOMES WHEN AND
WHERE THUNDERSTORM ACTIVITY WILL FIRE AS SHORTWAVE IMPULSE HEADS
EAST TOWARD THE WESTERN GREAT LAKES AND FRONTAL BOUNDARY
APPROACHES. ALTHOUGH THERE HAS BEEN A VARIETY OF SOLUTIONS AS TO
HOW THE SCENARIO WILL PLAY OUT...SEEMS THAT A WEAK CONSENSUS OF
THE GUIDANCE SUGGESTS THAT THUNDERSTORM ACTIVITY WILL DEVELOP NEAR
THE WISCONSIN-MICHIGAN BORDER...ALONG AND AHEAD OF FRONTAL
BOUNDARY FORECAST TO DRIFT SSE INTO NORTHERN WISCONSIN THIS
EVENING. THIS BOUNDARY MAY ALSO GET SOME REINFORCEMENT FROM LAKE
SUPERIOR BREEZE. THIS ACTIVITY SHOULD THEN SAG SOUTHWARD ACROSS
THE FORECAST AREA OVERNIGHT INTO MONDAY MORNING. SHOULD BE PLENTY
OF INSTABILITY OVER THE FORECAST AREA SUNDAY EVENING WITH MLCAPES
AROUND 3000 J/KG. BEST DEEP LAYER SHEAR TO SUSTAIN UPDRAFTS WILL
BE OVER THE NORTHERN HALF OF THE FORECAST AREA. SPC ADDED MOST
OF THE FORECAST AREA INTO A SLIGHT RISK FOR SEVERE LATE THIS
AFTERNOON AND INTO THE LATE EVENING HOURS WHICH SEEMS REASONABLE.
PRIMARY THREAT APPEARS TO BE DAMAGING WINDS AND PERHAPS SOME
LARGE HAIL. MODELS VARY AS TO THE TIMING THE CONVECTION WILL
FIRE...BEST GUESS IS SOMETIME IN THE 23-02Z TIME FRAME WITH
ACTIVITY MOVING SOUTH OR SOUTHEAST ACROSS THE FORECAST AREA TOWARD
MIDNIGHT. WILL ALSO NEED TO KEEP AN EYE ON A LOCALLY HEAVY
RAINFALL THREAT...ESPECIALLY IF ACTIVITY CAN TRAIN FROM WEST TO
EAST ALONG FRONTAL BOUNDARY LATER TONIGHT.
MORE UNCERTAINTY FOR MONDAY AS MODELS DIVERGE ON HOW LONG ACTIVITY
WILL PERSIST ALONG FRONTAL BOUNDARY EXPECTED TO BE LOCATED
SOMEWHERE OVER NORTHERN WISCONSIN. LOCATION OF RESIDUAL
THUNDERSTORM OUTFLOW IS ALSO A FACTOR AS TO WHERE ADDITIONAL
CONVECTION MAY FIRE AGAIN DURING THE DAY ON MONDAY. FOR NOW KEPT
BROAD BRUSH CHANCE POPS ACROSS THE ENTIRE FORECAST AREA. MAX TEMPS
ON MONDAY WILL BE DEPENDENT ON RESIDUAL CLOUD
COVER...PRECIPITATION AND LOCATION OF FRONTAL BOUNDARY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY
ISSUED AT 501 AM CDT SUN AUG 25 2013
WHILE THE CNTRL CONUS UPR RDG TO REMAIN THE MAIN WEATHER FEATURE
THRU MUCH OF THE UPCOMING WEEK...ITS SLOW RETROGRESSION FROM THE
MID-MS VALLEY TO THE CNTRL HI PLAINS WL ALLOW THE MEAN FLOW TO
TURN NW BY THU AND BRING SLIGHTLY COOLER/DRIER CONDITIONS TO NE
WI. MAIN FCST EMPHASIS TO BE THRU MID-WEEK AS A FRONTAL BOUNDARY
MOVES THRU AN UNSTABLE AIR MASS AND SETS THE STAGE FOR TSTMS. A
FEW OF THESE STORMS MAY BECOME STRONG TO SEVERE WITH LOCALLY HEAVY
RAINFALL. TEMPS TO REMAIN WELL ABOVE NORMAL TIL FURTHER NOTICE...
ESPECIALLY THRU THU.
PLENTY OF QUESTIONS LINGER FOR TUE STARTING WITH WHERE (IF) MON
NGT`S CONVECTION TO BE LOCATED...WHERE THE NRN WI FRONTAL BOUNDARY
TO RESIDE...WL ADDITIONAL PCPN DEVELOP ON THE EDGE OF THE CAP AND
COULD ANY OF THESE STORMS TURN SEVERE? THE KEY APPEARS TO BE THE
MON NGT CONVECTION SINCE IF IT WERE TO DEVELOP...MORE CLOUDS AND
BRIEF STABILIZATION WOULD OCCUR. IF THIS CONVECTION STAYS TO THE
NORTH...THIS WOULD ALLOW TEMPS TO SOAR ONCE AGAIN AND ALLOW THE
ATMOSPHERE TO REALLY DESTABILIZE BY THE AFTERNOON. TO TOP ALL OF
THIS OFF...THE MDLS BRING A WEAK SFC TROF INTO WI. HARD TO FATHOM
NOT SEEING ANY PCPN MON NGT...THUS HAVE SIDED WITH MENTIONING A
HIGHER POP ON TUE ACROSS FAR NE WI WHERE THE WEAKER CAP WL EXIST.
SEVERE POTENTIAL TO BE DICTATED BY HOW WARM WE CAN GET AND WHETHER
THAT APPROACHING WEAK SFC TROF CAN GENERATE ENUF LIFT TO BREAK THE
CAP. IF THE CAP IS BROKEN...WE COULD SEE A ROUND OF STRONG TO
SEVERE STORMS WITH LARGE HAIL...DAMAGING WINDS AND TORRENTIAL
DOWNPOURS.
SHWR/TSTM THREAT WOULD CARRYOVER INTO TUE EVENING UNTIL THE SFC
TROF EXITS THE AREA AND A WEAK AREA OF HI PRES BEGINS TO BUILD
ACROSS THE UPR MS VALLEY. ONLY CHANGE TO THIS PART OF THE FCST WAS
TO FOCUS PCPN CHCS TO THE EVENING WITH A CLEARING TREND FOR THE
OVRNGT HOURS. BY THE MIDDLE OF THE WEEK...THE UPR RDG IS PROGGED
TO HAVE RETROGRADED BACK TOWARD THE CNTRL PLAINS WTH THE MEAN FLOW
OVER THE GREAT LAKES TURNING MORE NW. WEAK HI PRES TO BE SITUATED
OVER THE WRN GREAT LAKES REGION ON WED...THUS A DECENT AMOUNT OF
SUNSHINE IS ANTICIPATED. 8H TEMPS TO STILL BE AROUND +20C...SO
TEMPS WL REMAIN RATHER WARM WITH A MINOR DROP IN DEW POINTS BEHIND
THE DEPARTED SFC TROF.
THERE ARE NOW CONCERNS FOR THU`S DRY FCST AS THE MDLS ARE
INDICATING THE NEXT MID-LEVEL SHORTWAVE TROF TO BE ROUNDING THE
CNTRL CONUS UPR RDG AND DIVING SE TOWARD WI. NOT SURE AT THIS
POINT WHETHER THIS POTENTIAL CONVECTION WOULD IMPACT ALL OF NE WI
OR DIVE SE ENUF TO ONLY AFFECT CNTRL WI. AT THIS POINT...FOLLOWED
THE CONSENSUS SOLUTION WHICH BRINGS A SLIGHT CHC POP TO MUCH OF
THE FCST AREA. TEMPS FOR WED LOOK TO BE SIMILAR TO WED WITH PLENTY
OF 80S TO GO AROUND.
ANOTHER AREA OF HI PRES IS EXPECTED TO BUILD SWD FROM CANADA
DURING THE THU NGT/FRI TIME PERIOD. DO NOT CARE FOR THE MINIMAL
POP ADVERTISED BY THE CONSENSUS SOLUTION AND PREFER TO GO DRY FOR
FRI WITH TEMPS GENERALLY IN THE 80-85 DEG RANGE. RETURN FLOW THEN
SETS UP OVER THE REGION NEXT WEEKEND WHICH WL LEAD TO WARMER
TEMPS...AN UPTICK IN HUMIDITY LEVELS AND THE POSSIBILITY OF WAA-
INDUCED PCPN CHCS. ATTM...ANY PCPN APPEARS TO BE WIDELY SCT AT
BEST WITH NO FOCUSING MECHANISM PRESENT.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 501 AM CDT SUN AUG 25 2013
GENERALLY VFR CONDITIONS TODAY. SCATTERED THUNDERSTORM ACTIVITY
WILL BEGIN TO SPREAD FROM NORTHWEST TO SOUTHEAST ACROSS THE
FORECAST AREA TONIGHT...HOWEVER CONFIDENCE LOW AS TO WHEN
CONVECTION WILL FIRE THIS EVENING AND HOW FAR SOUTH IT WILL
PROPAGATE OVERNIGHT. BEST CHANCE FOR MVFR CONDITIONS ASSOCIATED WITH
SCATTERED THUNDERSTORM ACTIVITY WILL BE AT NORTHERN TAF SITES AFTER
03Z.
.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ESB
LONG TERM......KALLAS
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
330 AM CDT SUN AUG 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SUN AUG 25 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES TODAY AND THUNDERSTORM
POTENTIAL TONIGHT.
...CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING
ALONG THE WEST COAST OF NORTH AMERICA AND STRONG SUBTROPICAL
RIDGING ENCOMPASSING KANSAS AND MISSOURI. AROUND THE RIDGING...
MONSOONAL MOISTURE AND SHORTWAVES WERE EMANATING FROM BAJA
CALIFORNIA / WHERE TROPICAL DEPRESSION IVO WAS LOCATED / NORTH-
NORTHEAST INTO THE DAKOTAS. ONE SUCH MONSOONAL SHORTWAVE...ENHANCED
BY CONVECTION...WAS TRACKING ACROSS NORTHERN ONTARIO. THE
CONVECTION WITH THIS SHORTWAVE EXTENDS SOUTH INTO NORTHERN MN AND
UPPER MI...BEING FED WITH MOISTURE BY A 35-50KT 850MB JET SEEN ON
VWP AND PROFILER DATA EXTENDING FROM NEBRASKA INTO WESTERN LAKE
SUPERIOR. EVEN A FEW STRAY SHOWERS EXTEND SOUTH INTO TREMPEALEAU
COUNTY. REGARDING THE MOISTURE...GOES DERIVED PRECIPITABLE WATER
IMAGERY SHOWED VALUES OF 1.5-2 INCHES ACROSS MUCH OF THE UPPER
MIDWEST. THE CONVECTION IS ALSO RIDING ALONG THE EDGE OF A HOT
AIRMASS ENCOMPASSING THE CENTRAL AND NORTHERN PLAINS AS WELL AS
THE UPPER MIDWEST. RAP SHOWED 700MB TEMPS OF 12C OR HIGHER FROM
DULUTH MN BACK INTO WESTERN NEBRASKA. MEANWHILE...DOWN AT
850MB...READINGS RANGED FROM 20-22C OVER THE FORECAST AREA TO
26-28C IN SOUTH DAKOTA. THE WARM AIRMASS EXTENDS DOWN TO THE
SURFACE...WHERE OVER THE FORECAST AREA...A SOUTH BREEZE AND
DEWPOINTS IN THE UPPER 60S TO LOW 70S HAS KEPT TEMPS AT OR ABOVE
70F. ALSO OF NOTE AT THE SURFACE IS A LOW PRESSURE TROUGH FROM
INTERNATIONAL FALLS MN SOUTHWEST TO PHILLIP SOUTH DAKOTA.
...HAZARDS...
1. HEAT ADVISORY REMAINS ON TRACK FOR TODAY AND IN FACT HEAT
INDICES MAY END UP HIGHER.
2. POTENTIAL CONVECTION TONIGHT COULD POSE A SEVERE RISK...
PRIMARILY NORTH OF I-90. ISOLATED LARGE HAIL AND DAMAGING WINDS
MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
25.00Z MODELS ARE IN VERY GOOD AGREEMENT SHOWING THAT A WEAK
500MB RIDGE AXIS PRESENT ACROSS MN WILL FLATTEN OUT TODAY...THEN
REBUILDS OVER THE DAKOTAS AHEAD OF A MORE DYNAMIC SHORTWAVE
LIFTING OUT OF ARIZONA INTO WYOMING. WITHIN THE 500MB
FLOW...MODELS SUGGEST A MONSOONAL SHORTWAVE SOMEWHERE IN NORTHWEST
COLORADO OR EASTERN WYOMING CURRENTLY TO CROSS CENTRAL MN AND
NORTHERN WI TONIGHT.
...DETAILS...
THE FLATTENING OF THE 500MB FLOW TODAY WILL HELP TO SPREAD MORE OF
THE WARMTH SEEN OVER SOUTH DAKOTA EASTWARD. 850MB TEMPS CLIMB TO
21-23C WHILE DOWN AT 925MB THEY JUMP TO 26-28C. MIXING TO THE 850MB
TEMPS WHICH SEEMS QUITE REASONABLE GIVEN THAT WE SHOULD HAVE FULL
SUN AND A BREEZY SOUTHWEST WIND YIELDS HIGHS IN THE LOW TO MID 90S.
NOTICED THAT THE RAP IS EVEN WARMER...SUGGESTING HIGHS OF 95-100.
THE REASON IS DUE TO SUPERADIABATIC EFFECTS...WHICH LOOK A BIT
OVERDONE. WITH DEWPOINTS HOVERING IN THE UPPER 60S TO LOWER 70S ALL
DAY...HEAT INDICES SHOULD TOP OUT BETWEEN 97-102.
NOW THE BIGGER QUESTION IS CONVECTION CHANCES FOR LATE THIS
AFTERNOON INTO TONIGHT. A COUPLE OF SCENARIOS EXIST...
1. THE 25.00Z NAM QUICKLY ERODES THE CAP BETWEEN 18-21Z FROM DULUTH
INTO WESTERN UPPER MI...PERHAPS CAUSED BY AN OUTFLOW BOUNDARY
EMANATING FROM CURRENT CONVECTION TRACKING ACROSS LAKE SUPERIOR.
THIS CONVECTION THEN DIVES SOUTH INTO NORTHERN SECTIONS OF THE
FORECAST AREA DURING THE EVENING INTO THE 850MB MOISTURE TRANSPORT
AXIS...FOLLOWING CORFIDI VECTORS. THE CONVECTION EVENTUALLY WANES
AFTER MIDNIGHT AS THE CAP RESTRENGTHENS. CONCERNED THAT THE NAM...IN
PARTICULAR ITS BMJ CONVECTIVE SCHEME...MAY BE ERODING THE CAP TOO
QUICKLY.
2. THE 25.00Z GFS...24.12Z ECMWF...THE BULK OF THE 25.03Z SREF
MEMBERS AND 25.00Z HIRES-ARW GENERALLY WAIT TO BREAK OUT CONVECTION
UNTIL AFTER 00Z ACROSS CENTRAL MN INTO NORTHERN WI...WHICH THEN
DROPS SOUTH MORE INTO THE FORECAST AREA AFTER 06Z. AGAIN THE
CONVECTION DIVES INTO THE 850MB MOISTURE TRANSPORT AXIS...FOLLOWING
CORFIDI VECTORS. ADDITIONALLY...THESE MODELS SUGGEST THAT SHORTWAVE
COMING OUT OF NORTHWEST COLORADO AND EASTERN WYOMING COULD BE AN
ENHANCING PLAYER.
3. THE 24.12Z HIRES-ARW...25.00Z CANADIAN...UKMET AND ECMWF HAVE THE
ONLY CONVECTION OCCURRING ACROSS NORTHERN WI AND UPPER MI TONIGHT...
ON THE NOSE OF THE 850MB MOISTURE TRANSPORT. THEY SUGGESTS THE CAP
HOLDS FOR LATE THIS AFTERNOON THROUGH TONIGHT...DIFFERENT FROM
EITHER OF THE ABOVE 2 SCENARIOS.
WHICH OF THE ABOVE 3 SCENARIOS PANS OUT BASICALLY DEPENDS ON THE
STRENGTH OF THE CAP. FOR NOW LEANED TOWARDS SCENARIO NUMBER 2 AS IT
HAS THE STRONGEST CONSENSUS...THOUGH CANNOT COMPLETELY RULE OUT
NUMBER 3. THEREFORE...HAVE LIMITED PRECIPITATION CHANCES TO NO MORE
THAN 50. THE SECOND SCENARIO ALSO POSES A MARGINAL SEVERE RISK NORTH
OF I-90...GIVEN 0-6 KM SHEAR VALUES REACHING 25-30 KT AND STRONG
INSTABILITY. MULTICELLS SEEM TO BE THE MOST LIKELY STORM MODE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN AUG 25 2013
...HAZARDS...
1. HEAT. HEAT ADVISORIES CONTINUE TO LOOK SOLID FOR MONDAY AND
TUESDAY...AND THERE IS EVEN SOME CONCERN WE MAY HAVE TO UPGRADE
PORTIONS OF THE AREA TO EXCESSIVE HEAT WARNING ON TUESDAY. THE
ADVISORY MAY ALSO HAVE TO BE EXTENDED INTO WEDNESDAY SOUTH OF
I-90. ANOTHER ROUND OF HEAT HAZARDS ARE POSSIBLE FOR LABOR DAY
WEEKEND.
2. STORMS. POTENTIAL FOR SOME SEVERE WEATHER MONDAY NIGHT IF THE
25.00Z NAM/GFS ARE CORRECT WITH ANOTHER THUNDERSTORM COMPLEX MOVING
THROUGH. ISOLATED LARGE HAIL AND DAMAGING WINDS MAIN HAZARDS.
...SYNOPTIC OVERVIEW...
THE SUBTROPICAL HIGH CENTERED OVER KANSAS AND MISSOURI REMAINS
PROGGED TO RETROGRADE WESTWARD TO SIT MOSTLY OVER KANSAS FOR
TUESDAY THROUGH THURSDAY. THIS RETROGRESSION IS CAUSED BY DEEPER
TROUGHING GRADUALLY FORMING OVER NEW ENGLAND. WHAT HAS BEEN
PROBLEMATIC IS AFTER THURSDAY. 24.12Z ECMWF KEPT A NORTHWEST FLOW
PATTERN GOING OVER THE FORECAST AREA FOR FRIDAY AND SATURDAY AS
THE TROUGH PERSISTS IN NEW ENGLAND. HOWEVER...THE NEW 25.00Z ECMWF
GOES ALONG WITH THE 25.00Z GFS TO ALLOW THE SUBTROPICAL HIGH AND
ASSOCIATED RIDGING TO SHIFT EAST QUICKER. THIS MEANS THAT HEAT
ISSUES ARE MORE LIKELY FOR LABOR DAY WEEKEND.
...PRECIPITATION DETAILS...
ALL INDICATIONS ARE THAT SHOULD CONVECTION FROM TONIGHT SHOULD
WEAKEN MONDAY MORNING DUE TO DIMINISHING MOISTURE TRANSPORT.
MAINTAINED 20-40 PERCENT CHANCES MAINLY ACROSS WI FOR THE
CONVECTION. THESE CHANCES SHIFT TO NORTH OF I-94 FOR THE AFTERNOON
WHERE THE REMNANT OUTFLOW/WARM FRONTAL BOUNDARY MAY SERVE AS A
TRIGGER FOR RENEWED CONVECTIVE DEVELOPMENT. OF COURSE...SHOULD THE
UKMET/CANADIAN/ECMWF PAN OUT...MONDAY WILL BE DRY. 20-40 PERCENT
CHANCES CONTINUE MONDAY NIGHT AND TUESDAY...GENERALLY ALONG AND
NORTH OF I-94...WHERE ANOTHER THUNDERSTORM COMPLEX MAY SLIDE
ACROSS AS INDICATED BY THE 25.00Z NAM/GFS. THESE STORMS WILL ALSO
HAVE THAT STRONGER SHORTWAVE LIFTING OUT OF WYOMING AT 12Z
MONDAY...HEADING INTO CENTRAL/NORTHERN MN BY 12Z TUESDAY FORCING
IT. NOTE THAT THE 25.00Z ECMWF/CANADIAN/UKMET ARE FARTHER NORTH
WITH THIS COMPLEX...SO MONDAY NIGHT AND TUESDAY COULD BE DRY AS
WELL...THUS THE 20-40 PERCENT CHANCES. SIMILAR TO TONIGHT...SHOULD
THE COMPLEX ROLL THROUGH...CANNOT RULE OUT SOME SEVERE WEATHER
POTENTIAL WITH THEM. COLD FRONTAL PASSAGE OCCURS TUESDAY NIGHT BUT
INDICATIONS ARE THAT THE AIRMASS MAY BE TOO CAPPED TO ALLOW ANY
CONVECTION WITH IT. IN FACT MOST MODELS ARE DRY. THEREFORE REDUCED
CHANCES SUCH THAT ONLY A 20 PERCENT CHANCE IS LEFT CLOSER TOWARDS
CENTRAL WI TO BLEND WITH NEIGHBORING OFFICES. WEDNESDAY STILL
LOOKS DRY WITH THE FRONT SOUTH OF THE AREA. SMALL CHANCES OF
STORMS RETURN THURSDAY THROUGH FRIDAY AS THE FRONT COMES BACK AS A
WARM FRONT. DRY CONDITIONS ARE ANTICIPATED SATURDAY WITH THE AREA
IN THE WARM SECTOR.
...TEMPERATURE DETAILS...
ON MONDAY...EVEN IF THERE ARE STORMS DISSIPATING IN THE MORNING
AND NEW ONES FIRE LATER IN THE DAY...ALL INDICATIONS ARE THAT
THERE WILL STILL BE PLENTY OF TIME FOR TEMPERATURES TO RECOVER.
925 AND 850MB TEMPS ARE ABOUT 1C HIGHER COMPARED TO TODAY...THUS
ANTICIPATING HIGHS 1-2 F HIGHER. UPPER 60S/LOW 70S DEWPOINTS STILL
SEEM REASONABLE RESULTING IN 100-105 HEAT INDICES.
TUESDAY STILL LOOKS LIKE THE HOTTEST DAY AS 925-850MB WINDS VEER
MORE WESTERLY...REALLY ADVECTING THE CORE OF THE HOT AIR OVER SOUTH
DAKOTA AND NEBRASKA AT US. 925MB TEMPS CLIMB TO AROUND 30C OVER MOST
OF THE FORECAST AREA WHICH IS USUALLY A GOOD CORRELATION FOR 100F
TEMPS. RAISED HIGHS A LITTLE MORE AND FURTHER INCREASES MAY BE
REQUIRED. DEWPOINTS LOOK LIKE THEY SHOULD HOLD THROUGH
EVAPOTRANSPORATION IN THE UPPER 60S/LOW 70S...WHICH MEANS HEAT
INDICES COULD CROSS THE 105 WARNING THRESHOLD IN SOME SPOTS.
WEDNESDAY IS BECOMING A BIT MORE CONCERNING AS THE 25.00Z ECMWF/GFS
ARE NOT AS QUICK BRINGING IN THE COOLER AIR BEHIND THE COLD FRONT.
925MB TEMPS STILL GET UP TO 28C OR HIGHER. THUS...INCREASED HIGHS A
FEW DEGREES TO SHOW UPPER 80S TO LOW 90S. THESE MAY NEED TO BE
INCREASED MORE...WHICH WOULD PROMPT AN EXTENSION OF THE HEAT
ADVISORY ANOTHER DAY.
THURSDAY AND FRIDAY WILL BE THE COOLEST DAYS...RELATIVELY SPEAKING
AS 925MB TEMPS ONLY COOL TO 25-27C. THEN IF THE NEW 25.00Z ECMWF AND
GFS ARE CORRECT...THESE CLIMB RIGHT BACK UP TO EVEN WARMER THAN THE
CURRENT HEAT STRETCH...TO 30-32C FOR SATURDAY AND SUNDAY. IF THIS
OCCURS...WE COULD EASILY BE LOOKING AT 100 DEGREE HEAT NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1111 PM CDT SAT AUG 24 2013
BUFKIT SOUNDINGS CONTINUE TO POINT TO AN INCREASING LOW LEVEL JET
THIS EVENING...WITH ABOUT 45 KTS BY 1500-2000 FT THROUGH 12-13Z OR
SO. SEE CONFIRMATION OF THIS IN RECENT VAD/PROFILER WINDS. WILL
CONTINUE THE MENTION OF LLWS IN THE TAFS AS A RESULT.
TIGHT PRESSURE GRADIENT PERSISTS INTO SUNDAY NIGHT...WITH LATE
MORNING/AFTERNOON MIXING RESULTING IN SOME HIGHER GUSTS. CONDITIONS
WILL STAY VFR WITH ONLY A FEW HIGH CLOUDS.
SUNDAY NIGHT...A SHORTWAVE TROUGH WILL TRACK EASTWARD ACROSS
SOUTHERN CANADA...BUT LAY A WEST-EAST RUNNING SFC FRONT OVER THE
REGION. INTERACTION WITH THE LOW LEVEL JET AND SOME INSTABILITY WILL
RESULT IN SHRA/TS ALONG AND NORTH OF THE BOUNDARY...WHICH THE MODELS
SUGGEST WILL SINK SOUTH OVERNIGHT...POTENTIALLY IMPACTING KRST/KLSE.
THIS TREND HAS BEEN RATHER CONSISTENT IN THE NAM/GFS/ECMWF OVER
THEIR PAST FEW RUNS...BUT NOT SURE HOW FAR SOUTH THIS PCPN WILL MAKE
IT BEFORE A WEAKENING LOW LEVEL JET RESULTS IN A DECREASE IN AREAL
COVERAGE. CLOUDS WILL BE ON THE INCREASE...BUT NORTH-SOUTH RUNNING
X-SECTIONS AND SOUNDINGS KEEP ANY CIGS VFR.
&&
.CLIMATE...
ISSUED AT 330 AM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
SUN 8/25 97/1948 97/1948
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ017-029-032>034-041>044-053>055-061.
MN...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-086>088-094>096.
IA...HEAT ADVISORY FROM NOON TODAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS TAUNTON MA
152 AM EDT TUE AUG 27 2013
.SYNOPSIS...
SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY
AS A SERIES OF DISTURBANCES MOVE ACROSS NEW ENGLAND. DRY WEATHER
WILL FOLLOW LATER THIS WEEK WITH ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS POSSIBLE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
2 AM UPDATE...
NOT MUCH CHANGE FROM PREVIOUS FORECAST. IMPRESSIVE SHORT WAVE OVER
NY STATE CONTINUES TO GENERATE WIDESPREAD SHOWERS WITH LOCALLY
HEAVY RAIN ACROSS MUCH OF NY INTO NEW ENGLAND. BULK OF RAIN MISSES
SOUTHEAST NH AND NORTHEAST MA OVERNIGHT. EARLIER DISCUSSION BELOW.
------------------------------------------------------------------
PWATS NEAR 2.0 INCHES WILL YIELD A LOW RISK OF MINOR POOR
DRAINAGE FLOODING OVERNIGHT IN THE URBAN AREAS. LATEST HRRR AND
12Z ECMWF SUGGEST STRONGEST FORCING FOR ASCENT ACROSS PA/NY AND
POSSIBLY INTO WESTERN MA AND CT GIVEN PROXIMITY OF LFQ OF UPPER
LEVEL JET STREAK...ENHANCING QG FORCING. THEREFORE HEAVIEST
RAINFALL LIKELY ACROSS WESTERN MA/CT AND POSSIBLY INTO RI.
RISK OF STRONG STORMS VERY LOW WITH INSTAB AND SHEAR OUT OF PHASE
WITH EACH OTHER...BEST INSTABILITY ALOFT ACROSS NORTHERN NEW
ENGLAND...WHILE STRONGEST WIND FIELD ALOFT ACROSS PA/NY/NJ NEAR
LFQ OF UPPER JET.
WARM AND MUGGY OVERNIGHT WITH DEW PTS IN THE M60S TO L70S
PRECLUDING TEMPS FROM FALLING MUCH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
TUESDAY...
ANY LEFTOVER SHOWERS/SCT TSTMS WILL EXIT ACROSS THE S COAST DURING
THE MORNING. HAVE LEFT IN LOW LIKELY POPS THERE EARLY...THEN WILL
STEADILY IMPROVE TOWARD MIDDAY. HOWEVER...WILL STILL BE UNDER
CYCLONIC FLOW ALOFT...SO STILL COULD SEE WIDELY SCT SHOWERS OR AN
ISOLD TSTM MAINLY ACROSS INLAND AREAS WITH FAIRLY GOOD INSTABILITY
IN PLACE. ONLY PROBLEM FOR ANY STRONGER STORMS TO DEVELOP WILL BE
LACK OF SHEAR AND WINDS AT THE SURFACE AND ALOFT REMAIN LIGHT. MAY
SEE BRIEF HEAVY DOWNPOURS WITH ANY SHOWER OR STORM. HIGHS WILL
REACH THE LOWER-MID 80S...EXCEPT THE MID-UPPER 70S ALONG THE
IMMEDIATE COAST.
TUESDAY NIGHT...
LONG WAVE TROUGHING REMAINS JUST E OF THE REGION...KEEPING JUST
ENOUGH CYCLONIC FLOW IN PLACE TO TRY TO ROTATE SOME WIDELY SCT
SHOWERS OR EVEN AN ISOLD TSTM TOWARD THE E COAST. OTHERWISE...ANY
SHOWERS/TSTMS INLAND SHOULD END WITHIN AN HOUR OR SO OF SUNSET.
WITH MUGGY AIRMASS REMAINING IN PLACE...EXPECT LOWS ONLY IN THE
60S ALONG WITH PATCHY FOG DEVELOPING MAINLY AFTER MIDNIGHT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS...
* UNSETTLED WEATHER EXPECTED WED AND THU
* DRY AND INCREASINGLY WARM WEATHER END OF THE WEEK
* UNSETTLED WEATHER RETURNS EARLY NEXT WEEK
MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE BROAD SCALE THOUGH THERE
ARE DEFINITELY DISCREPANCIES IN THE DETAILS...PARTICULARLY DURING
THE UNSETTLED PERIODS OF WEATHER. THE WPC IS OPTING FOR A BLEND OF
THE GEFS AND THE ECMWF ENSEMBLE MEANS WHICH ARE IN THE MIDDLE OF THE
SOLUTION ENVELOPE WHILE THE RESPECTIVE OPERATIONAL MODELS ARE
TRENDING TO THE OUTSIDE. THAT BEING SAID...WILL TRY TO USE AS MUCH
OF THE WPC FORECAST AS POSSIBLE TO INCORPORATE THE ENSEMBLE MEANS.
A SERIES OF LOW PRESSURE CENTERS WILL TRAVEL ALONG OR JUST SOUTH OF
40 N LATITUDE WEDNESDAY AND INTO THE MARITIMES THURSDAY AS HIGH
PRESSURE BUILDS INTO SOUTHERN NEW ENGLAND. HIGH PRESSURE WILL BE
THE DOMINANT WEATHER FEATURE FRIDAY AND SATURDAY THEN MOVES
OFFSHORE...ALLOWING LOW PRESSURE TO MOVE INTO QUEBEC AND BRINGING A
COLD FRONT THROUGH SOUTHERN NEW ENGLAND MONDAY.
WEDNESDAY AND THURSDAY...ONE OR MORE LOW PRESSURE CENTERS WILL MOVE
SOUTH OF SOUTHERN NEW ENGLAND...CONTINUING THE UNSETTLED WEATHER
OVER THE AREA TODAY AND TUESDAY. TRICKY FORECAST FOR SEVERE STORM
POTENTIAL. WHILE THERE IS MORE LIFT ON WEDNESDAY WITH LOW PRESSURE
NEARER TO SOUTHERN NEW ENGLAND...THE BETTER SHEAR AND COOLER
TEMPERATURES ALOFT COME ON THURSDAY WITH PLENTY OF INSTABILITY
AROUND BOTH DAYS. WILL HAVE TO CONTINUE TO MONITOR THE FORECAST FOR
THIS TIME PERIOD. TEMPERATURES SHOULD BE RIGHT AROUND TO JUST BELOW
NORMAL FOR LATE AUGUST.
FRIDAY AND SATURDAY...HIGH PRESSURE BUILDS INTO THE REGION AND WITH
IT COMES WARMER TEMPERATURES AS WELL. SOUTHWESTERLY TO WESTERLY
DOWNSLOPING FLOW WILL RESULT IN TEMPERATURES WELL ABOVE NORMAL
BRINGING ONE MORE SHOT OF SUMMER LIKE WEATHER TO THE AREA.
SUNDAY AND MONDAY...STRONG LOW PRESSURE MOVES THROUGH QUEBEC TO THE
MARITIMES BRINGING A COLD FRONT ACROSS SOUTHERN NEW ENGLAND MONDAY.
SHOWERS AND THUNDERSTORMS ARE POSSIBLE AHEAD OF THIS FRONT WITH THE
HEAT AND HUMIDITY STILL IN PLACE. MUCH OF THIS WILL DEPEND ON THE
SPEED OF THE FRONT...AMONG OTHER THINGS.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH TUESDAY NIGHT/...MODERATE CONFIDENCE.
IFR/LIFR IN RAIN SHOWERS ACROSS CT/RI AND SOUTH OF I-90 IN MA.
CONVERSELY VFR OVER NORTHEAST MA AND SOUTHEAST MA. RAIN SHIELD AND
LOW CIGS/VSBYS SLIDE SOUTHEAST TODAY WITH IMPROVING TO VFR FROM NW
TO SE AS THE DAY PROGRESSES. NEW SHOWERS/TSTMS WITH ISOLATED/WIDELY
SCATTERED IN AREAL COVERAGE ARE POSSIBLE ACROSS WESTERN CT/MA AND
SOUTHWEST NH THIS AFTERNOON. IFR IN LOW CLOUDS/VSBYS MAY LINGER MUCH
OF THE DAY OVER NANTUCKET/CAPE COD AND ISLANDS.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. HEAVIEST RAIN STAYS
SOUTHWEST OF TERMINAL.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. IMPROVING WEATHER THIS
AFTERNOON.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
WEDNESDAY AND THURSDAY...MODERATE CONFIDENCE. MAINLY VFR.
MVFR/IFR CONDITIONS LIKELY IN ANY SHOWERS AND THUNDERSTORMS THAT
DEVELOP ALONG WITH POSSIBLE FOG WEDNESDAY NIGHT.
FRIDAY AND SATURDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE.
HAVE KEPT SMALL CRAFTS THROUGH TUESDAY. SW WIND GUSTS UP TO 25
KT ACROSS THE SOUTHERN WATERS THROUGH AROUND MIDNIGHT WILL
DIMINISH. ALREADY NOTING SEAS UP TO 6 FT AT SEVERAL OF THE
SOUTHERN BUOYS WHICH WILL SLOWLY SUBSIDE TUESDAY.
WILL SEE INCREASING CHANCE FOR SHOWERS/TSTMS TONIGHT AS WEAK LOW
PRES MOVES TOWARD THE WATERS. WILL SEE REDUCED VSBYS IN ANY
PRECIP ALONG WITH PATCHY FOG DEVELOPING. VSBYS WILL IMPROVE BY
AROUND MIDDAY TUESDAY AS THE FOG DISSIPATES AND PRECIP MOVES
OFFSHORE. WILL LIKELY SEE FOG REDEVELOP TUE NIGHT.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
WHILE WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT CRITERIA FROM
MID WEEK THROUGH THE END OF THE WEEK...THERE IS POTENTIAL FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY AND THURSDAY. ALSO
VISIBILITIES MAY BE LIMITED WEDNESDAY NIGHT IN PATCHY FOG.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
ANZ254>256.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT THIS MORNING FOR ANZ235-
237.
&&
$$
SYNOPSIS...RLG/EVT
NEAR TERM...NOCERA/RLG/EVT
SHORT TERM...EVT
LONG TERM...RLG
AVIATION...NOCERA/RLG
MARINE...RLG/EVT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
400 AM CDT TUE AUG 27 2013
.DISCUSSION...
324 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE TODAY`S HEAT...THEN
TEMPS/POPS AS WE TEETER ON THE PERIPHERY OF UNSEASONABLY STRONG LATE
SUMMER UPPER HOT DOME INTO THE WEEKEND.
THE CARCASS OF SUNDAY NIGHT`S MCS PROVIDED A SHROUD OF FAIRLY DENSE
CIRRUS OVER THE AREA MONDAY AFTERNOON HOLDING TEMPS ABOUT 2-4F
COOLER THAN EXPECTED. ONCE AGAIN EARLY THIS MORNING MCS ACTIVITY IS
FESTERING ABOUT TO OUR NORTH ON THE PERIPHERY OF THE UPPER RIDGE.
CONVECTIVELY ENHANCED VORT DRIVING THIS MCS APPEARS TO BE PUSHING
INTO NORTHERN PORTIONS OF LAKE MICHIGAN ALREADY WITH BACK EDGE OF
CIRRUS SHIELD MOVING INTO NW WISCONSIN. HRRR SEEMS TO HAVE A GOOD
HANDLE ON ONGOING CONVECTIVE TRENDS AND IT...ALONG WITH THE MAJORITY
OF THE OTHER GUIDANCE...SUGGESTS THAT TODAY`S CIRRUS DEBRIS WILL
CLEAR OUT BY EARLY AFTERNOON AND ALLOW FOR STRONG HEATING TO TAKE
PLACE...ESPECIALLY NORTHWESTERN CWA. LOW LEVEL THERMAL RIDGE
MOVING INTO THE AREA WITH 925MB TEMPS PROGGED TO RISE TO 26-28C
NORTHWESTERN CWA WHICH WOULD EASILY SUPPORT MIDDLE IF NOT UPPER
90S. IN THE PAST HOUR CONVECTION HAS FLARED OVER NORTHEAST MINNESOTA
WHICH IS CONCERNING AS 850-300MB THICKNESS SUGGESTS THAT COULD SINK
SOUTHWARD AND SPREAD MORE CIRRUS ACROSS THE AREA TODAY.
GIVEN POTENTIAL FOR DEBRIS CLOUDINESS TO LINGER AGAIN TODAY SPLIT
THE DIFFERENCE FOR HIGHS BETWEEN WHAT PROGGED 925MB TEMPS WOULD
SUPPORT AND WHAT CLIMO INFLUENCED MOS NUMBERS FORECAST. ASSUMING
DEWPOINTS DON`T MIX OUT AND ASSUMING CIRRUS CLEARS OUT THEN WE WOULD
GET CLOSE TO THE 105F HEAT INDEX ADVISORY CRITERIA THIS AFTERNOON
NORTH/NORTHWEST AREAS. GIVEN A FORECAST OF CONDITIONS NOT MEETING
CRITERIA AND LOW CONFIDENCE IN THEM EVEN GETTING AS BAD AS I HAVE IN
THE GRIDS...WOULD NOT NORMALLY ISSUE AN ADVISORY...BUT WITH
HEADLINES OUT FOR AREAS NORTH/WEST OF OUR CWA AND POTENTIAL FOR NEAR
RECORD HIGHS DECIDED TO MAKE THE W/W/A MAP PRETTY AND HOIST AN
ADVISORY FOR NORTH CENTRAL ILLINOIS. IF TRENDS THIS MORNING SUGGEST
THAT CIRRUS WONT BE A BIG DEAL THEN DAY SHIFT COULD CONSIDER
EXTENDING THE ADVISORY FARTHER EAST INTO THE CHICAGO AREA.
ANOTHER SHORTWAVE OVER THE EASTERN DAKOTAS THIS MORNING IS PROGGED
TO RIDE THE RIM OF THE RIDGE EAST INTO WISCONSIN THIS AFTERNOON AND
WILL PROBABLY RE-IGNITE THUNDERSTORMS TO OUR NORTH THIS AFTERNOON
WITH THESE STORMS POTENTIALLY CLIPPING OUR NORTHERN AND NORTHEASTERN
CWA THIS EVENING AS THE MOVE SOUTHEASTWARD. MODERATELY STRONG MID
LEVEL FLOW AND FAIRLY STRONG INSTABILITY (ASSUMING TDS DONT MIX OUT)
COULD SUPPORT A LOW END SEVERE THREAT WITH ANY STORMS THAT DO
MEANDER INTO OUR CWA TONIGHT.
LAKE ENHANCED COLD FRONT WILL MOVE INTO THE CWA EARLY WEDNESDAY
MORNING PROGRESSING SOUTHWARD INTO OUR SOUTHERN CWA BY AFTERNOON.
BETTER FORCING ALOFT SHOULD REMAIN TO OUR EAST BUT AM CONCERNED THAT
MOISTURE/INSTABILITY POOLING AND LOW LEVEL CONVERGENCE ALONG THE
FRONT COULD BE ENOUGH TO KICK OFF A THUNDERSTORM WEDNESDAY
AFTERNOON. SLIGHTLY COOLER AIR MASS WILL FILTER IN BEHIND THE
FRONT...WITH COOLING MOST NOTICEABLE NEAR LAKE MICHIGAN. AHEAD OF THE
FRONT WILL BE ANOTHER STEAMY DAY AND WITH BETTER DEWPOINT POOLING
COULD ACTUALLY END UP BEING HOTTER/MORE HUMID IN OUR SOUTHERN CWA
TOMORROW THAN TODAY...BUT THAT WILL HINGE ON THE AMOUNT OF
CLOUDINESS SOMETHING WHICH WILL BE MORE EASILY DIAGNOSED TONIGHT.
LOW LEVEL BAROCLINIC ZONE HANGS UP IN THE NEIGHBORHOOD THROUGH THE
END OF THE WEEK WITH WEAK NORTHWEST FLOW IMPULSES LIKELY TO RIPPLE
AROUND THE PERIPHERY OF THE HEAT DOME MEANS AT LEAST SOME POTENTIAL
FOR THUNDERSTORMS TONIGHT UNTIL STRONG COLD FRONT MOVES THROUGH THIS
WEEKEND. HAVE KEPT FORECAST DRY FOR NOW WEDNESDAY NIGHT THROUGH
THURSDAY BUT NW FLOW`S LIKE THIS ARE NOTORIOUS FOR PRODUCING
"SURPRISES" SO STAY TUNED!
HEADING INTO THE SECOND HALF OF THE LABOR DAY WEEKEND THE DIFFERENCE
BETWEEN THE 27/00Z RUN OF THE ECMWF WHEN COMPARED TO THE 25/12Z RUN
IS ABOUT AS DRAMATIC I`VE EVER SEEN IN THE WARM SEASON. FOR DAYS
MEDIUM RANGE MODELS HAD BEEN ADVERTISING RECORD BREAKING HEAT AND
NOW AFTER STARTING TO TREND SHARPLY COLDER WITH THE 26/12Z RUN THE
LATEST ECMWF NOW FORECASTS NEAR RECORD COLD TEMPERATURES BY MONDAY
WITH H8 TEMPS NEARING 0C! THE REMAINDER OF THE MEDIUM RANGE MODELS
HAVE BEEN TRENDING TOWARD THIS EARLIER FROPA/STRONG COLD PUSH
SOLUTION BUT STILL LAG WELL BEHIND THE UNSEASONABLY COLD ECMWF. IF
ECMWF WERE TO VERIFY WITH THIS INTENSE COOL SNAP THEN OUR FORECAST
WILL LIKELY TAKE A COUPLE MORE CYCLES TO CATCH UP WITH SUCH AN
ABRUPT CHANGE BUT HAVE TRENDED TEMPS DOWN SIGNIFICANTLY FROM THE
INITIALIZED ALLBLEND GUIDANCE...THOUGH IF LATEST EC VERIFIES HIGHS
MONDAY WOULD LIKELY BE IN THE 60S! NEEDLESS TO SAY FORECAST
CONFIDENCE IN THIS TIME PERIOD WILL REMAIN LOW UNTIL WE BEGIN TO SEE
MODELS CONVERGE ON A SOLUTION AND REMAIN MORE STABLE FROM RUN TO RUN.
IZZI
&&
.CLIMATE...
HERE ARE THE RECORD HIGHS FOR TUESDAY...
CHICAGO ROCKFORD
TUESDAY 97 (1973) 97 (1953)
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* SLIGHT CHANCE FOR SCT SHRA/TSRA THIS EVENING.
JEE
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE IS OVER THE SOUTHEAST US WHILE LOW PRESSURE IS OVER
SOUTH DAKOTA. THE LOW PRESSURE WILL TRACK ACROSS MN AND WI TODAY
BEFORE DRIFTING SOUTHEAST OVER NORTHERN IL AND IN THIS EVENING AND
TONIGHT. CURRENTLY HIGH LEVEL CLOUD COVER IS SINKING SOUTH FROM A
CONVECTIVE COMPLEX OVER NORTHERN WI...BUT THE CONVECTION WILL
REMAIN WELL NORTH OF THE TERMINALS.
SW WIND GUSTS WILL ONCE AGAIN INCREASE BY MID MORNING WITH
SLIGHTLY STRONGER SUSTAINED SPEEDS THAN YESTERDAY...ARND 12KT.
GUSTS WILL BE ARND 18KT WITH OCNL GUSTS ARND 20KT ESPECIALLY LATE
THIS AFTN. GUSTS DIMINISH THIS EVENING AS THE LOWS COLD FRONT
APPROACHES FROM THE NORTH. FOR WINDS...THINKING WINDS WILL BEGIN
TO VEER TO THE NW LATE TONIGHT ARND 10Z.
FOR PRECIP...GUIDANCE SUGGESTS ISOL-SCT SHRA/TSRA WILL DEVELOP
AROUND THE EASTERN TERMINALS BTWN 00 AND 06Z BUT STILL THINKING
THE MAJORITY OF SHRA/TSRA WILL REMAIN NORTH AND EAST OF THE
TERMINALS CLOSER TO THE FORCING ALOFT. AS SUCH KEPT THE TAFS DRY
FOR NOW...BUT THAT MAY CHANGE IF SHRA/TSRA ARE MORE PLENTIFUL THAN
EXPECTED.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN SCT SHRA/TSRA THIS EVENING BTWN 00 AND
06Z...BUT MEDIUM CONFIDENCE IN SHRA/TSRA REMAINING OUTSIDE OF
TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...SLIGHT CHANCE TSRA OVERNIGHT.
FRIDAY...SLIGHT CHANCE TSRA.
SATURDAY AND SUNDAY...VFR.
MDB
&&
.MARINE...
225 AM CDT
LOW PRESSURE OVER SOUTH DAKOTA THIS MORNING WILL PASS OVER THE LAKE
TODAY WITH ITS COLD FRONT SLIDING DOWN THE LAKE TONIGHT. AS SUCH
GUSTY SW WINDS ARE ONCE AGAIN EXPECTED OVER THE SOUTHERN HALF OF THE
LAKE TODAY WITH LIGHTER EAST WINDS OVER THE NORTHERN HALF. WINDS
TURN NW TO N BEHIND THE FRONT TONIGHT THEN AS THE HIGH SETTLES IN
OVER THE REGION...WINDS BECOME LIGHT AND VARIABLE. THE HIGH SHIFTS
EAST THURSDAY NIGHT WITH WINDS BECOMING SOUTH ON FRIDAY. LIGHT
WINDS ARE EXPECTED THROUGH THE END OF THIS WEEK...BUT A STRONG LOW
FORMS OVER SASKATCHEWAN FRIDAY NIGHT. GUIDANCE SUGGESTS THE LOW
WILL PASS NORTH OF LAKE MICHIGAN BUT STRONG NW WINDS ARND 30 KT ARE
EXPECTED BEHIND THE LOWS COLD FRONT SUNDAY NIGHT INTO MONDAY
ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011...NOON
TUESDAY TO 8 PM TUESDAY.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
324 AM CDT TUE AUG 27 2013
.DISCUSSION...
324 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE TODAY`S HEAT...THEN
TEMPS/POPS AS WE TEETER ON THE PERIPHERY OF UNSEASONABLY STRONG LATE
SUMMER UPPER HOT DOME INTO THE WEEKEND.
THE CARCASS OF SUNDAY NIGHT`S MCS PROVIDED A SHROUD OF FAIRLY DENSE
CIRRUS OVER THE AREA MONDAY AFTERNOON HOLDING TEMPS ABOUT 2-4F
COOLER THAN EXPECTED. ONCE AGAIN EARLY THIS MORNING MCS ACTIVITY IS
FESTERING ABOUT TO OUR NORTH ON THE PERIPHERY OF THE UPPER RIDGE.
CONVECTIVELY ENHANCED VORT DRIVING THIS MCS APPEARS TO BE PUSHING
INTO NORTHERN PORTIONS OF LAKE MICHIGAN ALREADY WITH BACK EDGE OF
CIRRUS SHIELD MOVING INTO NW WISCONSIN. HRRR SEEMS TO HAVE A GOOD
HANDLE ON ONGOING CONVECTIVE TRENDS AND IT...ALONG WITH THE MAJORITY
OF THE OTHER GUIDANCE...SUGGESTS THAT TODAY`S CIRRUS DEBRIS WILL
CLEAR OUT BY EARLY AFTERNOON AND ALLOW FOR STRONG HEATING TO TAKE
PLACE...ESPECIALLY NORTHWESTERN CWA. LOW LEVEL THERMAL RIDGE
MOVING INTO THE AREA WITH 925MB TEMPS PROGGED TO RISE TO 26-28C
NORTHWESTERN CWA WHICH WOULD EASILY SUPPORT MIDDLE IF NOT UPPER
90S. IN THE PAST HOUR CONVECTION HAS FLARED OVER NORTHEAST MINNESOTA
WHICH IS CONCERNING AS 850-300MB THICKNESS SUGGESTS THAT COULD SINK
SOUTHWARD AND SPREAD MORE CIRRUS ACROSS THE AREA TODAY.
GIVEN POTENTIAL FOR DEBRIS CLOUDINESS TO LINGER AGAIN TODAY SPLIT
THE DIFFERENCE FOR HIGHS BETWEEN WHAT PROGGED 925MB TEMPS WOULD
SUPPORT AND WHAT CLIMO INFLUENCED MOS NUMBERS FORECAST. ASSUMING
DEWPOINTS DON`T MIX OUT AND ASSUMING CIRRUS CLEARS OUT THEN WE WOULD
GET CLOSE TO THE 105F HEAT INDEX ADVISORY CRITERIA THIS AFTERNOON
NORTH/NORTHWEST AREAS. GIVEN A FORECAST OF CONDITIONS NOT MEETING
CRITERIA AND LOW CONFIDENCE IN THEM EVEN GETTING AS BAD AS I HAVE IN
THE GRIDS...WOULD NOT NORMALLY ISSUE AN ADVISORY...BUT WITH
HEADLINES OUT FOR AREAS NORTH/WEST OF OUR CWA AND POTENTIAL FOR NEAR
RECORD HIGHS DECIDED TO MAKE THE W/W/A MAP PRETTY AND HOIST AN
ADVISORY FOR NORTH CENTRAL ILLINOIS. IF TRENDS THIS MORNING SUGGEST
THAT CIRRUS WONT BE A BIG DEAL THEN DAY SHIFT COULD CONSIDER
EXTENDING THE ADVISORY FARTHER EAST INTO THE CHICAGO AREA.
ANOTHER SHORTWAVE OVER THE EASTERN DAKOTAS THIS MORNING IS PROGGED
TO RIDE THE RIM OF THE RIDGE EAST INTO WISCONSIN THIS AFTERNOON AND
WILL PROBABLY RE-IGNITE THUNDERSTORMS TO OUR NORTH THIS AFTERNOON
WITH THESE STORMS POTENTIALLY CLIPPING OUR NORTHERN AND NORTHEASTERN
CWA THIS EVENING AS THE MOVE SOUTHEASTWARD. MODERATELY STRONG MID
LEVEL FLOW AND FAIRLY STRONG INSTABILITY (ASSUMING TDS DONT MIX OUT)
COULD SUPPORT A LOW END SEVERE THREAT WITH ANY STORMS THAT DO
MEANDER INTO OUR CWA TONIGHT.
LAKE ENHANCED COLD FRONT WILL MOVE INTO THE CWA EARLY WEDNESDAY
MORNING PROGRESSING SOUTHWARD INTO OUR SOUTHERN CWA BY AFTERNOON.
BETTER FORCING ALOFT SHOULD REMAIN TO OUR EAST BUT AM CONCERNED THAT
MOISTURE/INSTABILITY POOLING AND LOW LEVEL CONVERGENCE ALONG THE
FRONT COULD BE ENOUGH TO KICK OFF A THUNDERSTORM WEDNESDAY
AFTERNOON. SLIGHTLY COOLER AIR MASS WILL FILTER IN BEHIND THE
FRONT...WITH COOLING MOST NOTICEABLE NEAR LAKE MICHIGAN. AHEAD OF THE
FRONT WILL BE ANOTHER STEAMY DAY AND WITH BETTER DEWPOINT POOLING
COULD ACTUALLY END UP BEING HOTTER/MORE HUMID IN OUR SOUTHERN CWA
TOMORROW THAN TODAY...BUT THAT WILL HINGE ON THE AMOUNT OF
CLOUDINESS SOMETHING WHICH WILL BE MORE EASILY DIAGNOSED TONIGHT.
LOW LEVEL BAROCLINIC ZONE HANGS UP IN THE NEIGHBORHOOD THROUGH THE
END OF THE WEEK WITH WEAK NORTHWEST FLOW IMPULSES LIKELY TO RIPPLE
AROUND THE PERIPHERY OF THE HEAT DOME MEANS AT LEAST SOME POTENTIAL
FOR THUNDERSTORMS TONIGHT UNTIL STRONG COLD FRONT MOVES THROUGH THIS
WEEKEND. HAVE KEPT FORECAST DRY FOR NOW WEDNESDAY NIGHT THROUGH
THURSDAY BUT NW FLOW`S LIKE THIS ARE NOTORIOUS FOR PRODUCING
"SURPRISES" SO STAY TUNED!
HEADING INTO THE SECOND HALF OF THE LABOR DAY WEEKEND THE DIFFERENCE
BETWEEN THE 27/00Z RUN OF THE ECMWF WHEN COMPARED TO THE 25/12Z RUN
IS ABOUT AS DRAMATIC I`VE EVER SEEN IN THE WARM SEASON. FOR DAYS
MEDIUM RANGE MODELS HAD BEEN ADVERTISING RECORD BREAKING HEAT AND
NOW AFTER STARTING TO TREND SHARPLY COLDER WITH THE 26/12Z RUN THE
LATEST ECMWF NOW FORECASTS NEAR RECORD COLD TEMPERATURES BY MONDAY
WITH H8 TEMPS NEARING 0C! THE REMAINDER OF THE MEDIUM RANGE MODELS
HAVE BEEN TRENDING TOWARD THIS EARLIER FROPA/STRONG COLD PUSH
SOLUTION BUT STILL LAG WELL BEHIND THE UNSEASONABLY COLD ECMWF. IF
ECMWF WERE TO VERIFY WITH THIS INTENSE COOL SNAP THEN OUR FORECAST
WILL LIKELY TAKE A COUPLE MORE CYCLES TO CATCH UP WITH SUCH AN
ABRUPT CHANGE BUT HAVE TRENDED TEMPS DOWN SIGNIFICANTLY FROM THE
INITIALIZED ALLBLEND GUIDANCE...THOUGH IF LATEST EC VERIFIES HIGHS
MONDAY WOULD LIKELY BE IN THE 60S! NEEDLESS TO SAY FORECAST
CONFIDENCE IN THIS TIME PERIOD WILL REMAIN LOW UNTIL WE BEGIN TO SEE
MODELS CONVERGE ON A SOLUTION AND REMAIN MORE STABLE FROM RUN TO RUN.
IZZI
&&
.CLIMATE...
HERE ARE THE RECORD HIGHS FOR TUESDAY...
CHICAGO ROCKFORD
TUESDAY 97 (1973) 97 (1953)
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SLIGHT CHANCE FOR SCT SHRA/TSRA THIS EVENING.
JEE
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE IS OVER THE SOUTHEAST US WHILE LOW PRESSURE IS OVER
SOUTH DAKOTA. THE LOW PRESSURE WILL TRACK ACROSS MN AND WI TODAY
BEFORE DRIFTING SOUTHEAST OVER NORTHERN IL AND IN THIS EVENING AND
TONIGHT. CURRENTLY HIGH LEVEL CLOUD COVER IS SINKING SOUTH FROM A
CONVECTIVE COMPLEX OVER NORTHERN WI...BUT THE CONVECTION WILL
REMAIN WELL NORTH OF THE TERMINALS.
SW WIND GUSTS WILL ONCE AGAIN INCREASE BY MID MORNING WITH
SLIGHTLY STRONGER SUSTAINED SPEEDS THAN YESTERDAY...ARND 12KT.
GUSTS WILL BE ARND 18KT WITH OCNL GUSTS ARND 20KT ESPECIALLY LATE
THIS AFTN. GUSTS DIMINISH THIS EVENING AS THE LOWS COLD FRONT
APPROACHES FROM THE NORTH. FOR WINDS...THINKING WINDS WILL BEGIN
TO VEER TO THE NW LATE TONIGHT ARND 10Z.
FOR PRECIP...GUIDANCE SUGGESTS ISOL-SCT SHRA/TSRA WILL DEVELOP
AROUND THE EASTERN TERMINALS BTWN 00 AND 06Z BUT STILL THINKING
THE MAJORITY OF SHRA/TSRA WILL REMAIN NORTH AND EAST OF THE
TERMINALS CLOSER TO THE FORCING ALOFT. AS SUCH KEPT THE TAFS DRY
FOR NOW...BUT THAT MAY CHANGE IF SHRA/TSRA ARE MORE PLENTIFUL THAN
EXPECTED.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN SCT SHRA/TSRA THIS EVENING BTWN 00 AND
06Z...BUT MEDIUM CONFIDENCE IN SHRA/TSRA REMAINING OUTSIDE OF
TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...SLIGHT CHANCE TSRA OVERNIGHT.
FRIDAY...SLIGHT CHANCE TSRA.
SATURDAY AND SUNDAY...VFR.
MDB
&&
.MARINE...
225 AM CDT
LOW PRESSURE OVER SOUTH DAKOTA THIS MORNING WILL PASS OVER THE LAKE
TODAY WITH ITS COLD FRONT SLIDING DOWN THE LAKE TONIGHT. AS SUCH
GUSTY SW WINDS ARE ONCE AGAIN EXPECTED OVER THE SOUTHERN HALF OF THE
LAKE TODAY WITH LIGHTER EAST WINDS OVER THE NORTHERN HALF. WINDS
TURN NW TO N BEHIND THE FRONT TONIGHT THEN AS THE HIGH SETTLES IN
OVER THE REGION...WINDS BECOME LIGHT AND VARIABLE. THE HIGH SHIFTS
EAST THURSDAY NIGHT WITH WINDS BECOMING SOUTH ON FRIDAY. LIGHT
WINDS ARE EXPECTED THROUGH THE END OF THIS WEEK...BUT A STRONG LOW
FORMS OVER SASKATCHEWAN FRIDAY NIGHT. GUIDANCE SUGGESTS THE LOW
WILL PASS NORTH OF LAKE MICHIGAN BUT STRONG NW WINDS ARND 30 KT ARE
EXPECTED BEHIND THE LOWS COLD FRONT SUNDAY NIGHT INTO MONDAY
ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011...NOON
TUESDAY TO 8 PM TUESDAY.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
357 AM CDT TUE AUG 27 2013
.SYNOPSIS...
ISSUED AT 349 AM CDT TUE AUG 27 2013
LARGE...NEARLY STATIONARY UPPER LEVEL HIGH CENTERED OVER EASTERN KS
AND MO AND DOME OF UNSEASONABLY WARM AIR ALOFT CONTINUES TO DOMINATE
THE SYNOPTIC WEATHER PICTURE. TONIGHT/S PRIMARY MCS...ROUNDING THE
TOP OF THE RIDGE WAS EVIDENT ON SATELLITE AND RADAR IMAGERY MOVING
INTO WESTERN LOWER MI...WHILE ADDITIONAL THUNDERSTORMS WERE
DEVELOPING FURTHER UPSTREAM NEAR DLH. AN ASSOCIATED SHIELD OF THIN
CI WAS COVERING MUCH OF EASTERN IA AND NORTHERN IL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED OVER EASTERN SD WITH A SURFACE
COLD FRONT/TROUGH REACHING EAST-NORTHEAST ACROSS CENTRAL MN AND
WI. SURFACE TEMPERATURES WERE IN THE LOWER TO MID 70S WITH
DEWPOINTS IN THE MID 60S TO AROUND 70 OVER THE FORECAST AREA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT TUE AUG 27 2013
FOCUS IS ON POTENTIALLY RECORD BREAKING HEAT TODAY AS THERMAL RIDGE
ALOFT OVERHEAD WILL SUPPORT THE HOTTEST TEMPERATURES SO FAR OF
THE ON-GOING HEAT WAVE. DEEP MIXING AHEAD OF THE APPROACHING
FRONT IN THE NORTHERN PLAINS AND UPPER MS VALLEY WILL TAP INTO THE
THERMAL RIDGE OF 850 TEMPERATURES IN THE RANGE OF 22 TO 23 DEGREES
C. THIS SUPPORTS HIGHS IN THE MID TO UPPER 90S...AND CONTINUES A
TREND OF 1 TO 3 DEGREES DAY TO DAY WARMING TREND SINCE THE
WEEKEND. BASED ON VERIFICATION...WILL CONTINUE TO BUFFER MAXES
ALONG THE MORE MOIST HIGHWAY 20 CORRIDOR DOWN A DEGREE OR TWO. THE
KEY TO HOW HIGH THE HEAT INDEX GETS WILL BE HOW SURFACE DEWPOINTS
RESPOND TO STRONGER WINDS AND DEEP MIXING TODAY. FORECAST MODELS
ARE IN A COUPLE DIFFERENT CAMPS...WITH THE RAP SUGGESTING DRYING
OUT TO THE UPPER 50S TO LOWER 60 BY AFTERNOON...WHILE THE BULK OF
OTHER SHORT TERM MODELS ARE MUCH MORE MOIST WITH SOME SUGGESTING
POOLING OF LOWER TO MID 70S ACROSS THE NORTH. BASED ON
VERIFICATION FROM YESTERDAY HERE AND UPSTREAM IN THE
PLAINS...DEWPOINTS WILL MORE LIKELY RISE A FEW DEGREES EARLY THIS
MORNING...THEN SETTLE IN THE INTO THE MID TO UPPER 60S IN THE
AFTERNOON AS SW WINDS INCREASE TO 10 TO 15 MPH. UNLIKE
YESTERDAY...THE CLOUD SHIELD FROM THE NOCTURNAL CONVECTION SHOULD
BE OUT OF THE REGION BY MID MORNING...YIELDING NEAR FULL SUNSHINE
FOR THE AFTERNOON. HOWEVER...WILL NEED TO WATCH THE NW WI COMPLEX TRENDS
CLOSELY...AS THIS COULD POSSIBLY LEAD TO ANOTHER CI SHIELD IF IT
REMAINS STRONG...FOR LATER THIS MORNING.
HEAT INDEX READINGS THUS ARE EXPECTED TO REACH 100 TO 104 BY EARLY
AFTERNOON OVER MUCH OF THE FORECAST AREA...WITH A GENERAL GRADIENT
FROM LOWER VALUES EAST TO HIGHER WEST AND NW. THE ON-GOING HEAT
ADVISORY WILL THUS REMAIN INTACT...AND IS EXTENDED INTO WED AS
COVERED IN THE LONG TERM AFD SEGMENT.
RECORD TEMPERATURES...AS MENTIONED IN THE CLIMATE SEGMENT
BELOW...APPEAR TO BE MOST AT RISK AT CID AND BRL.
VERY WARM AND HUMID CONDITIONS WILL THEN PREVAIL TONIGHT AS THE
SURFACE COOL FRONT SETTLES SOUTH TO ROUGHLY ALONG THE I-80 CORRIDOR
BY DAWN. ASSOCIATED MOISTURE POOLING AND LIGHT WINDS WILL MAKE FOR
UNCOMFORTABLE CONDITIONS. TEMPERATURES WILL BE IN THE UPPER 70S
TO LOWER 80 FOR MUCH OF THE NIGHT...COOLING TO LOWS AROUND SUNRISE
IN THE LOWER TO MID 70S. THERE IS A LOW POTENTIAL FOR CONVECTION
ALONG THIS BOUNDARY...BUT ANYTHING THAT DEVELOPS WILL LIKELY STAY
WELL EAST OF THE FORECAST AREA...WHERE THE CAP WILL BE WEAKER AND
HAVE KEPT MENTIONABLE POPS OUT OF THE FORECAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 349 AM CDT TUE AUG 27 2013
FORECAST FOCUS ON HOT AND HUMID WEATHER INTO THE WEEKEND BUT THEN
MUCH COOLER BY LABOR DAY.
WEDNESDAY THROUGH SATURDAY...HAVE EXTENDED THE HEAT ADVISORY FOR
MOST OF THE CWA INTO EARLY WEDNESDAY EVENING. A WEAK BACK DOOR COLD
FRONT WILL PUSH ACROSS THE CWA BUT THE MAIN IMPACT WILL BE TO POOL
HIGHER DEWPOINTS ALONG THE BOUNDARY. MOST OF THE CWA WILL HAVE
AFTERNOON TEMPERATURES IN THE LOWER TO MID 90S WITH DEWPOINTS IN THE
LOWER 70S CREATING HEAT INDEX VALUES OF 100 TO 104. THE EXCEPTION
WILL BE OUR FAR NORTH AND NORTHEAST COUNTIES WHERE TEMPERATURES AND
DEWPOINTS WILL BE SOMEWHAT LOWER BEHIND THE FRONT.
THERE WILL BE A BRIEF BREAK ON THURSDAY WITH NORTHEAST WINDS BEHIND
THE FRONT KEEPING HEAT INDEX VALUES BELOW ADVISORY CRITERIA. HOWEVER
BY FRIDAY THE WEAK FRONT RETURNS AS A WARM FRONT AND LIFTS TO OUR
NORTHEAST BRINGING DEWPOINTS BACK INTO THE LOWER 70S AND HIGHS IN
THE LOWER TO MID 90S. HEAT INDEX VALUES WILL ONCE AGAIN PUSH INTO
THE 100 TO 104 RANGE AND THIS COULD POSSIBLY CONTINUE INTO SATURDAY.
THERE ARE SMALL CHANCES OF THUNDERSTORMS FOR BOTH THURSDAY NIGHT AND
FRIDAY NIGHT...BUT CONFIDENCE IS LOW. THIS IS BASED ON THE
OPERATIONAL MODELS INDICATING RIDGE RIDERS MOVING ACROSS THE UPPER
MIDWEST BUT THE BULK OF THE STORMS SHOULD REMAIN ACROSS MN AND WI.
SUNDAY AND LABOR DAY...THE ECMWF FOR 3 STRAIGHT RUNS HAS SHOWN THE
PLUNGE OF MUCH COOLER TEMPERATURES INTO THE MIDWEST AND GREAT LAKES.
IN FACT...THIS MODEL BRINGS THE 2C 850 MB TEMPERATURE LINE TO NEAR
CHICAGO ON LABOR DAY. CONFIDENCE GROWING THAT THIS IS FOR REAL AS
THE GFS/GEM ARE ALSO ON BOARD WITH THIS DEEPENING TROUGH IN THE
EAST...BUT NOT NEARLY AS COLD AS THE ECMWF. THE STRONG COLD FRONT
SHOULD PUSH INTO THE DVN CWA SOMETIME ON SUNDAY AND THE OPERATIONAL
MODELS SUGGEST THE POTENTIAL FOR AT LEAST ISOLATED TO SCATTERED
THUNDERSTORMS ACCOMPANYING THE FRONT...SUNDAY AFTERNOON OR EVENING.
FOR NOW THE GRIDS ARE DRY BUT LATER SHIFTS WILL NEED TO RE-EVALUATE
THE CHANCES OF THUNDERSTORMS. SURROUNDING OFFICES CONSENSUS WAS TO
LOWER TEMPERATURES ON SUNDAY AND LABOR DAY WITH THE FRONT STRONGER
AND ARRIVING SOONER THAN EARLIER DEPICTED.
AT THIS POINT IN THE GAME LABOR DAY LOOKS VERY PLEASANT WITH
COMFORTABLE HUMIDITY AND MAXIMUM TEMPERATURES IN THE 80S...ACTUALLY
AROUND 80 IN OUR FAR NORTHEAST CWA.
THIS COOLER AIR IS SHORT LIVED AS IT APPEARS THE HEAT AND HUMIDITY
QUICKLY RETURN BY THE MIDDLE OF NEXT WEEK.
HAASE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1132 PM CDT MON AUG 26 2013
VFR CONDITIONS AND SOUTH TO SOUTHWESTERLY WINDS WILL PERSIST
THROUGH TUESDAY EVENING. THERE IS STILL A LOW THREAT OF 3-5SM
VSBYS IF FOG AROUND SUNRISE ESPECIALLY WEST OF THE MISSISSIPPI
RIVER WHERE THE HIGH CLOUDS WILL BE THIN. A WEAK COLD FRONT WILL
SAG SOUTH INTO NORTHEAST IOWA AND SOUTHERN WISCONSIN BY LATE
TUESDAY EVENING.
&&
.CLIMATE...
ISSUED AT 349 AM CDT TUE AUG 27 2013
RECORD HIGHS FOR AUGUST 27...
MOLINE.........97 IN 1976
CEDAR RAPIDS...97 IN 1955
DUBUQUE........94 IN 1895
BURLINGTON.....97 IN 1955
RECORD HIGHS FOR AUGUST 28...
MOLINE.........96 IN 1953
CEDAR RAPIDS...96 IN 1955
DUBUQUE........97 IN 1984
BURLINGTON.....96 IN 1945
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR BUCHANAN-DELAWARE-
DUBUQUE-JACKSON.
HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR BENTON-CEDAR-CLINTON-
DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-
LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR HANCOCK-HENDERSON-
MCDONOUGH-MERCER-ROCK ISLAND-WARREN.
HEAT ADVISORY FROM NOON TODAY TO 10 PM CDT THIS EVENING FOR
CARROLL-JO DAVIESS-STEPHENSON.
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT WEDNESDAY FOR BUREAU-
HENRY IL-PUTNAM-WHITESIDE.
MO...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...HAASE
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS GOODLAND KS
225 AM MDT TUE AUG 27 2013
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 222 AM MDT TUE AUG 27 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE SCALE RIDGE STILL
IN PLACE ACROSS THE CENTRAL CONUS. THERE HAS BEEN A GENERAL
WEAKENING OF THE RIDGE CENTER...WITH CURRENT MAX HEIGHT AROUND
595/596DM. A SHORTWAVE TROUGH OVER EASTERN TEXAS SHOWS GOOD
REFLECTION IN BOTH WV AND HEIGHT FIELD AND COULD BE A MINOR FACTOR
IN TEMPS ON WED.
WITH RIDGE WELL ENTRENCHED OVER OUR CWA...THERE WILL BE VERY LITTLE
CHANGE IN THE HOT/DRY CONDITIONS. MODELS SHOW THE SHORTWAVE TROUGH
OVER EASTERN TEXAS ROUNDING SOUTH AND THEN WESTERN EDGE OF THE RIDGE
CENTER THROUGH WED NIGHT. AS HAS BEEN THE CASE THE LAST FEW
DAYS...THERE SHOULD BE GOOD FORCING AND AT LEAST SOME ELEVATED
INSTABILITY WITH THIS FEATURE. MODEL SOUNDINGS STILL SHOW DEEP DRY
AIR MASS IN PLACE...SO OTHER THAN A BRIEF INCREASE IN CLOUDS AND
SLIGHTLY COOLER TEMPS ALOFT I AM NOT ANTICIPATING PRECIP WITH THIS
FEATURE OVER OUR CWA. GENERAL TREND WILL BE A WEAKENING OF THE LEE
TROUGH WITH GRADIENT SHIFTING EASTWARD. THIS SHOULD SUPPORT LESS
WINDY CONDITIONS THROUGH THE REST OF THE FORECAST PERIOD...THOUGH A
FEW GUSTS IN THE 20-30MPH CANT BE RULED OUT THIS AFTERNOON WITH PEAK
MIXING.
REGARDING TEMPS THROUGH THURSDAY...IT LOOKS LIKE A CONTINUATION OF
THE LAST FEW DAYS WITH HIGHS GENERALLY IN THE UPPER 90S/LOW 100S. THE
ONE EXCEPTION WILL BE WED WHEN HIGHS MAY BE ABOUT 5-7F
COOLER...WHICH STILL PUTS HIGHS ACROSS THE CWA IN THE MID-UPPER 90S
FOR MANY LOCATIONS.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 222 AM MDT TUE AUG 27 2013
MEDIUM RANGE MODEL CONSENSUS IS FOR GRADUAL SLIGHT WEAKENING OF THE
UPPER RIDGE EARLY IN EXTENDED PERIOD. A RELATIVELY SIGNIFICANT
SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN PLAINS AND GREAT LAKES
REGION OVER THE WEEKEND ALONG THE NORTHERN EDGE OF THE RIDGE. AN
ASSOCIATED COLD FRONT WILL MOVE SOUTH/SOUTHWESTWARD TOWARD THE AREA.
THE NEW 00Z ECMWF IS STRONGER WITH THIS SHORTWAVE AND PROGRESSES THE
COLD FRONT FURTHER SOUTHWEST INTO OUR AREA LATE SUNDAY INTO MONDAY.
THE GFS IS LESS AGGRESSIVE WITH SOUTH/SOUTHWEST PROGRESSION OF THE
COLD FRONT BUT DOES SHOW AN INCREASE IN DEEP MOISTURE ACROSS THE
AREA SUNDAY AND MONDAY WITH PWAT VALUES SLIGHTLY EXCEEDING
CLIMATOLOGY. THIS IS ENOUGH TO JUSTIFY KEEPING AT LEAST A VERY LOW
POP IN THE NORTHERN PORTION OF THE FORECAST AREA SUNDAY AND MONDAY.
BY LATE MONDAY A MORE HIGHLY AMPLIFIED PATTERN EVOLVES WITH UPPER
RIDGE STRENGTHENING ONCE AGAIN OVER THE PLAINS BETWEEN PACIFIC
NORTHWEST TROUGH AND DEEPENING TROUGH OVER THE EASTERN CONUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1106 PM MDT MON AUG 26 2013
VFR CONDITIONS ARE EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF
PERIOD. WINDS AT KMCK WILL GRADUALLY DIMINISH OVERNIGHT.
OTHERWISE...WINDS ON TUESDAY WILL NOT BE AS STRONG AS THE PAST FEW
DAYS WITH THE SURFACE TROUGH MOVING INTO THE AREA AND REDUCING THE
PRESSURE GRADIENT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...024
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
354 AM EDT TUE AUG 27 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 418 PM EDT MON AUG 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE
CENTERED OVER MO/KS RESULTING IN ACYC FLOW FROM THE NRN PLAINS
THROUGH THE UPPER MS VALLEY INTO THE GREAT LAKES. WAA IN ADVANCE OF
AN UPSTREAM SHORTWAVE TROUGH MOVING INTO SW NORTH DAKOTA SUPPORTED
AN AREA OF LIGHT TO MODERATE RAIN WITH ONLY ISOLD TSRA. AT THE
SFC...THE CONVECTION THIS MORNING HELPED PUSH THE WEAK FRONTAL
BOUNDARY INTO NRN WI AND EXTENDED FROM NEAR HYR TO GRB. TEMPS TO THE
SOUTH OF THE FRONT HAVE AGAIN CLIMBED TO AROUND 90 WHILE MORE
MODERATE READINGS IN THE LOW TO MID 80S PREVAILED TO THE NORTH.
DEWPOINTS THROUGH THE REGION WERE NEAR 70F WITH 12Z OBSERVED AND
FCST SOUNDINGS SHOWING PWAT VALUES AROUND 2.0 INCHES(200 PCT OF
NORMAL).
EXPECT THAT AS THE ND SHRTWV MOVES TO THE EAST AND WAA INCREASES
THIS EVENING...EXPECT SHRA/TSRA TO DEVELOP AND QUICKLY IN INCREASE
IN COVERAGE BY LATE EVENING IN THE VCNTY OF THE SFC-800 MB FRONT
FROM CNTRL MN INTO NW WI. EVEN THOUGH THE MODELS HAVE TRENDED
FARTHER SOUTH WITH THE PCPN AND SHOW THE MOST FAVORABLE 310K
ISENTROPIC LIFT REMAINING SOUTH OF THE CWA...THERE IS STILL
CONSIDERABLE UNCERTAINTY ON THE LOCATION OF THE STRONGEST CONVECTION.
MOST OF THE HIGHER RES MODELS KEEP NEARLY ALL THE PCPN SOUTH OF
THE CWA WHILE THE GFS/ECMWF AND HIGH RES RAPID REFRESH BRING PCPN
THROUGH MAINLY THE SW HALF OF THE CWA. SO...THE HIGHER POPS/QPF WERE
SHIFTED TO THE SOUTH WITH LOCATIONS ALONG THE WI BORDER SEEING THE
GREATEST POTENTIAL FOR STRONG TSRA.
WITH MUCAPE VALUES INTO THE 1000-1500 J/KG RANGE AND EFFECTIVE SHEAR
TO AROUND 30 KT...THERE IS THE POTENTIAL FOR MULTICELL CLUSTERS THAT
COULD PRODUCE VERY HEAVY RAIN AND LCL WIND DAMAGE...SIMILAR TO LAST
NIGHT. FCST CORFIDI VECTORS SUGGEST THAT STORM ELEMENTS SHOULD KEEP
ENOUGH FORWARD MOTION TO LIMIT POTENTIAL FOR EXCESSIVE RAINFALL.
HOWEVER...ONE TO TWO INCHES AMOUNTS MAY AGAIN BE COMMON ALONG THE
PATH OF HEAVIER CLUSTERS. ANY LEFTOVER SHRA/TSRA TUE MORNING OVER
MAINLY THE S CNTRL CWA IS EXPECTED TO DIMINISH AND SAG OFF TO THE SE
BY EARLY TO MID AFTERNOON.
WITH 850 MB TEMPS REMAINING AROUND 18C...MAX TEMPS SHOULD ALSO BE
SIMILAR TO TODAY WITH HIGHS INTO THE LOW TO MID 80S WITH SLIGHTLY
COOLER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 354 AM EDT TUE AUG 27 2013
WEDNESDAY CONTINUES TO LOOK LIKE A BREAK FROM THE PERIOD OF ACTIVE
WEATHER THAT HAS BEEN AFFECTING THE UPPER GREAT LAKES REGION. THIS
IS DUE TO THE MAIN SHORTWAVE ROUNDING THE UPPER RIDGE MOVING THROUGH
EASTERN ONTARIO AND A HIGH PRESSURE RIDGE NOSING SOUTH OVER THE AREA
FROM A HIGH OVER HUDSON BAY. THIS HIGH WILL INFLUENCE OUR WEATHER
INTO WEDNESDAY NIGHT.
SINCE THE HIGH IS PROVIDING PLENTY OF DRY AIR ALOFT...THE FORECAST
COMES DOWN TO THE NEAR SURFACE FEATURES. IN THIS CASE...THE LOW
LEVEL WINDS HAVE A LARGE AFFECT ON THE WEATHER FOR WEDNESDAY
MORNING...AS THE LIGHT NORTHERLY FLOW WILL LIKELY PUSH FOG OVER THE
AREA FROM LAKE SUPERIOR. THERE WAS A DECENT AMOUNT OF FOG OVER
EASTERN LAKE SUPERIOR THIS PAST EVENING...SO AS LONG AS THAT
CONTINUES TODAY...WOULD EXPECT IT TO BE AFFECTING THE AREA TONIGHT
INTO WEDNESDAY MORNING. THE WINDS ARE FAIRLY LIGHT DURING THAT
PERIOD...SO THAT MAY LIMIT THE INLAND EXTENT ALTHOUGH CLEARING
SKIES TONIGHT WILL AID IN DEVELOPMENT FOR INLAND LOCATIONS. WILL
CONTINUE THE IDEA STARTED SEVERAL DAYS AGO FOR THE FOG ON WEDNESDAY
MORNING...WITH THE THICKEST FOG NEAR LAKE SUPERIOR...THE HIGHER
TERRAIN OF THE NORTH CENTRAL AND KEWEENAW...ALONG WITH THE EAST
WHERE THE FOG IS CURRENTLY THE THICKEST. ONCE DIURNAL HEATING TAKES
HOLD...WOULD EXPECT THE FOG TO DIMINISH AND MIX OUT THROUGH THE
MORNING WITH ONLY A FEW LOW BASED STRATOCU REMAINING TOWARDS EARLY
AFTERNOON. WILL CONTINUE THAT IDEA FOR THE SKY GRIDS ON WEDNESDAY.
OTHERWISE...WITH THE INCREASING SUNSHINE...SHOULD BE ANOTHER ABOVE
NORMAL DAY ACROSS THE AREA. HIGHS WILL RANGE FROM MID 70S NEAR LAKE
SUPERIOR TO MID 80S TOWARDS THE WISCONSIN BORDER WHERE THERE WILL BE
GREATER SUNSHINE.
WEDNESDAY NIGHT SHOULD BE DRY BUT THE NEXT SHORTWAVE WILL
APPROACHING THE AREA FROM NORTH DAKOTA ON THURSDAY. DID LINGER THE
FOG OVER LAKE SUPERIOR INTO WEDNESDAY NIGHT SINCE THE NORTHERLY FLOW
IS FAIRLY LIGHT AND THE EXPECTED DEWPOINTS UPSTREAM ARE IN THE LOW
60S. THIS WON/T BE THAT MUCH DRIER AND THE LIMITED MIXING MAY KEEP
FOG AROUND. IF THAT OCCURS...IT MAY HOLD ON INTO THURSDAY OR BEYOND
DUE TO THE LIGHT WINDS.
DEFINITELY SEEMS LIKE BETTER AGREEMENT IN GFS/ECMWF ON THE TRACK OF
THE SHORTWAVE ACROSS UPPER MICHIGAN AND NORTHERN WISCONSIN THURSDAY
AFTERNOON INTO THURSDAY NIGHT. LIKE TONIGHT...BEST 850-700MB
WAA/MOISTURE TRANSPORT IS FOCUSED JUST TO THE SOUTHWEST OF OUR
CWA. THAT LINES UP WELL WITH THE LOCATION OF THE BEST INSTABILITY
(1000-1500 J/KG OF MUCAPE IN NORTHERN WISCONSIN) AND LOW LEVEL JET.
THUS...WOULD THINK WE WILL BE ON THE NORTHERN SIDE OF THE BEST
PRECIPITATION AND WILL RUN CHANCE POPS OVER THE SOUTHWEST HALF OF
THE CWA THURSDAY NIGHT INTO FRIDAY MORNING.
THIS SHORTWAVE WILL DEPART AND PUT THE AREA UNDER ANOTHER WEAK
CANADIAN HIGH PRESSURE RIDGE FOR FRIDAY AFTERNOON INTO FRIDAY
NIGHT. MODELS DIFFER GREATLY FOR THE LABOR DAY WEEKEND ON HOW TO
HANDLE THE NEXT COUPLE OF WAVES EXITING THE TROUGH OFF THE PACIFIC
NORTHWEST AND THE BROAD LOW PRESSURE SYSTEM MOVING ACROSS THE AREA.
THERE HAS BEEN A TREND OVER THE LAST DAY OF HEADING TOWARDS MORE
NORMAL TEMPERATURES WITH THE BREAK DOWN OF THE NORTHERN SIDE OF THE
UPPER RIDGE. WILL START TRENDING TEMPERATURES DOWN...BUT NOT AS LOW
AS THE 26-12Z ECMWF WHICH HAD HIGHS IN THE 60S FOR SUNDAY AND
MONDAY. LATE ARRIVING 00Z ECMWF IS EVEN COLDER WITH 0C 850MB TEMPS
OVER THE KEWEENAW AT 00Z MONDAY AND MUCH OF THE CWA AT 12Z. THIS
WOULD END UP GIVING HIGHS IN THE 50S AND THE POTENTIAL FOR LAKE
ENHANCED CLOUDS ON MONDAY WITH A STRONG UPPER TROUGH MOVING THROUGH.
DEFINITELY SOMETHING TO WATCH OVER THE COMING DAYS. WITH THE WIDE
SPREAD ON TIMING/LOCATION OF PRECIPITATION FOR THE WEEKEND...WILL
JUST CONTINUE A CONSENSUS OF THE MODELS WITH SLIGHT AND LOW CHANCE
POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 354 AM EDT TUE AUG 27 2013
SHRA/TSRA WILL IMPACT THE REGION OVERNIGHT AT IWD AND AT SAW WITH
POSSIBLE MVFR CONDITIONS. CMX SHOULD REMAIN DRY OVERNIGHT. VFR
CONDITIONS EXPECTED FOR ALL TAF SITES ON TUE AND TUE NIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 AM EDT TUE AUG 27 2013
LIMITED PRESSURE GRADIENTS ACROSS LAKE SUPERIOR SHOULD KEEP WINDS
BELOW 20KTS THROUGH THE FORECAST PERIOD. FOG EXPANDED ACROSS EASTERN
LAKE SUPERIOR YESTERDAY AND WOULD EXPECT IT TO SPREAD WEST ACROSS
THE REST OF THE LAKE TODAY WITH HIGH DEWPOINTS AND THE SHOWERS THAT
ARE MOVING THROUGH. AS WINDS TURN TO THE NORTH TONIGHT...EXPECT THE
FOG TO PUSH SOUTH THROUGH WEDNESDAY MORNING AND THEN DIMINISH SOME
AS SLIGHTLY DRIER CANADIAN AIR MOVES SOUTH OVER THE LAKE THROUGH
WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1203 AM CDT TUE AUG 27 2013
.UPDATE...
ISSUED AT 1203 AM CDT TUE AUG 27 2013
LATEST LOCAL/REGIONAL RADAR SHOWS A DECAYING AREA OF SHOWERS AND
ISOLATED THUNDERSTORMS OVER THE TURTLE MOUNTAINS WITH ISOLATED
SHOWERS NEAR RICE LAKE AND MAX IN WARD AND MCLEAN COUNTIES. WATER
VAPOR IMAGERY SHOWS NORTH DAKOTA ON THE PERIMETER OF AN UPPER
RIDGE CENTERED OVER SOUTHEAST NEBRASKA. SEVERAL SHORTWAVES WILL
CONTINUE TO ROTATE AROUND THE HIGH AND SCOOT THROUGH NORTH DAKOTA.
THE HRRR MODEL IS CAPTURING A BROKEN AREA OF SHOWERS IN SOUTH
CENTRAL MONTANA ASSOCIATED WITH ANOTHER SHORTWAVE. THIS IS
FORECAST TO SHIFT INTO WESTERN NORTH DAKOTA BY AROUND 12Z. HAVE
ADJUSTED POPS TO ACCOUNT FOR THIS. OTHERWISE WILL MAINTAIN THE
MOSTLY CLEAR TO PARTLY CLOUDY SKIES OVERNIGHT WITH PATCHY FOG.
UPDATE ISSUED AT 946 PM CDT MON AUG 26 2013
AS OF 245 UTC...ONE LAST STORM REMAINS ACROSS NORTH CENTRAL NORTH
DAKOTA NEAR MOHALL. OTHERWISE...THUNDERSTORM ACTIVITY HAS QUICKLY
DIMINISHED WITH SUNSET AND THE LACK OF A LOW LEVEL JET. DID ADD
FOG TO MOST OF NORTHWEST AND CENTRAL NORTH DAKOTA GIVEN LIGHT
WINDS AND THE VERY HIGH HUMIDITY LEVELS IN PLACE.
UPDATE ISSUED AT 600 PM CDT MON AUG 26 2013
AS OF 2245 UTC...STRONG TO SEVERE THUNDERSTORMS CONTINUE TO
INTENSIFY ACROSS FAR NORTHEAST MONTANA THROUGH DUNN COUNTY IN
NORTH DAKOTA ALONG A WEAK CONVERGENCE LINE. ML CAPE VALUES NEAR
2500 J/KG ARE ANALYZED ALONG THIS LINE ON THE SPC RAPV2
MESOANALYSIS...WHICH APPEARS TO BE HANDLING THE CURRENT
ENVIRONMENT BETTER THAN THE RAPV1. GIVEN DEEP LAYER SHEAR OF 40
KTS...SUPERCELLS ARE LIKELY. THE PRIMARY THREATS ARE DAMAGING
WINDS WITH DOWNDRAFT CAPE VALUES NEAR 1200 J/KG. GIVEN THE HIGH
FREEZING LEVELS AND PWATS...HAIL SURVIVABILITY IS LIMITED. ALSO
MONITORING LOCATIONS NEAR THE SOUTH DAKOTA BORDER ALONG ANOTHER
CONVERGENCE LINE IN A SIMILIAR ENVIRONMENT...WITH THE LATEST 21
UTC HRRR CONTINUING TO SUGGEST CONTINUED GROWTH OF CONVECTION THAT
HAS BEEN INITIATING OVER THE PAST HOUR FOR THESE AREAS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 324 PM CDT MON AUG 26 2013
MAIN CONCERNS THIS SHORT TERM WILL BE THUNDERSTORMS. BROAD FEATURES
INCLUDE A LARGE AND PERSISTENT RIDGE IN THE UPPER ATMOSPHERE. ON THE
WESTERN SIDE OF THE RIDGE A TROPICAL PLUME IS IDENTIFIED ON THE
WATER VAPOR IMAGE. A WEAK SHORTWAVE NOW MOVING THROUGH NORTHEAST
WYOMING WILL SUPPORT CONVECTION THIS EVENING AND OVERNIGHT. AS THE
SHORT WAVE TROUGH TRANSITS ACROSS THE RIDGE EXPECT AN INCREASE IN
THUNDERSTORMS ...WHICH SO FAR TODAY APPEAR TO BY LIMITED BY THE WARM
MID LEVEL TEMPERATURES. WITH THE ADDED LIFT FROM THE SHORTWAVE
EXPECT THUNDERSTORMS TO BECOME MORE ACTIVE LATE THIS AFTERNOON AND
EVENING...MAINLY SOUTH CENTRAL AND SOUTHEAST. MULTIPLE WEAK OUTFLOW
BOUNDARIES EXIST ACROSS THE SOUTH CENTRAL...AND CLOUDS ACROSS NORTH
DAKOTA SUPPORTING DIFFERENTIAL HEATING AND ENHANCING THE THERMAL
BOUNDARY.
TONIGHT...THUNDERSTORM THREAT WILL MOVE EAST. ENDED THE CHANCE OF
THUNDERSTORMS AFTER 1 AM. SOUTHEAST UPSLOPE FLOW AND WEAK SHORTWAVE
ENERGY IN FLOW ALOFT WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS
SOUTHWEST TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CDT MON AUG 26 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THE OVERALL UPPER LEVEL PATTERN REMAINS NEARLY UNCHANGED WITH A
CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND DETERMINISTIC
MODELS. FINER DETAILS CONTINUE TO COME TO A CONSENSUS AMONG THE
MODELS EARLY IN THE PERIOD...BUT SIGNIFICANT DIFFERENCES STILL EXIST
OVER THE WEEKEND AND EARLY NEXT WEEK. EXCEPT FOR A FEW ADJUSTMENTS
TO BUMP UP POPS WHERE MODELS ARE MORE IN LINE...STILL UTILIZED A
MODEL BLEND SOLUTION FOR POPS DURING MOST OF THE LONG TERM PERIOD.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BETTER THUNDERSTORM CHANCES
APPEAR IN STORE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WHEN A FEW
UPPER LEVEL WAVES MOVE INTO THE NORTHERN PLAINS AND TEMPORARILY
BREAKS DOWN THE UPPER LEVEL RIDGE. DETERMINISTIC MODELS INDICATE
INCREASED WARM ADVECTION WEDNESDAY AFTERNOON AND EVENING AHEAD OF
SURFACE LOW PRESSURE THAT DEVELOPS OVER THE WESTERN DAKOTAS. POPS
ARE GREATEST WEDNESDAY IN THE WEST HALF DURING THE DAY...WITH HIGHER
CHANCE POPS SPREADING EAST WEDNESDAY NIGHT AS THE INCREASED WARM
ADVECTION AND COOLING UPPER LEVEL TEMPERATURES WITH THE SHORTWAVES
SHOULD SUSTAIN CONVECTION AS IT TRANSLATES EAST.
THURSDAY AND THURSDAY NIGHT...THE LAST OF THIS ROUND OF UPPER LEVEL
SHORTWAVE ENERGY IMPULSES IS PROGGED TO MOVE EAST ACROSS THE STATE
THURSDAY BEFORE EXITING THE REGION THURSDAY AFTERNOON/NIGHT. UPPER
LEVEL RIDGING QUICKLY REBOUNDS ON THURSDAY NIGHT.
FRIDAY THROUGH MONDAY...THE MODELS IN GENERAL KEEP THE UPPER LEVEL
RIDGE ESTABLISHED OVER THE CENTRAL US THROUGH THE WEEKEND. THE
MODELS DIFFER AFTER THIS...WITH THE ECMWF KEEPING THE RIDGE IN PLACE
WHILE THE GFS SOLUTION DEPICTS THE RIDGE BROADENING AND MOVING EAST.
THUS WILL CONTINUE WITH A MODEL BLEND HERE WHICH GIVES MAINLY SLIGHT
CHANCE POPS EACH DAY.
TEMPERATURES SHOULD REMAIN ABOVE AVERAGE THROUGH SATURDAY WITH HIGHS
MAINLY 85-90 NORTH TO LOW TO MID 90S SOUTH. THE MODEL BLEND HINTS OF
TEMPERATURES MOVING BACK TOWARDS SEASONABLE SUNDAY/MONDAY WITH HIGHS
75-85 NORTH AND IN THE 80S SOUTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1203 AM CDT TUE AUG 27 2013
PATCHY FOG WITH BRIEF IFR/MVFR VSBYS CAN BE EXPECTED AT
KMOT/KBIS/KJMS THROUGH 13Z TUESDAY. OTHERWISE SCT/BKN VFR CIGS
NEXT 24HR. ISOLATED SHOWERS AND THUNDERSTORMS REMAIN A POSSIBILITY
AS WELL.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...WAA
LONG TERM...JV
AVIATION...KS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
552 AM EDT TUE AUG 27 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEASTERN STATES WILL REMAIN IN PLACE
THROUGH MIDWEEK. LOW PRESSURE WILL MOVE EAST ACROSS THE LOWER
GREAT LAKES TONIGHT AND DRAG A WEAK COLD FRONT SOUTH THROUGH THE
AREA ON WEDNESDAY. HIGH PRESSURE WILL RETURN TO THE AREA TOWARD
THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
WIDELY SCATTERED SHOWERS ACROSS THE AREA EARLY THIS MORNING BUT
MOSTLY WEST FROM FDY AREA TO MNN MOVING SOUTH. MAIN ISSUE FOR
TODAY WILL BE THE MCS MOVING SOUTHEAST THROUGH WI. CIRRUS WILL
MOVE INTO NWRN OHIO BY 4 TO 5AM WILL HRRR BRINGING DYING COMPLEX
INTO THE AREA 12-15Z. BROUGHT LIKELY POPS TO THE AREA FROM KCLE TO
KTOL BY 15Z WITH CHANCE POPS ELSEWHERE. INCREASED POPS TO LIKELY
SOUTHEAST AS SYSTEM DROPS SOUTHEAST THROUGH THE AREA. THROUGH THE
AFTERNOON DROPPED POPS BACK TO CHANCE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TONIGHT FOLLOWED SREF/NAM BLEND WHICH SHOWS A DEVELOPING OR
POSSIBLY ONGOING CONVECTIVE SYSTEM TO OUR NORTHWEST THAT WILL DROP
ACROSS THE AREA THROUGH THE EVENING AND EARLY OVERNIGHT HOURS.
WENT A BIT AGGRESSIVE ON POPS WITH CATEGORICAL POPS ACROSS A LARGE
PORTION OF THE AREA. WILL CONTINUE THIS INTO EARLY WEDNESDAY AS A
WEAK COLD FRONT DROPS THROUGH THE AREA BEFORE DROPPING BACK TO
LIKELY/CHANCE DURING THE AFTERNOON. WEDNESDAY NIGHT AND THURSDAY
DRIER MORE STABLE AIR MOVES IN FROM THE NORTH BEHIND THE COLD
FRONT. CONTINUE DRY THURSDAY NIGHT. FRIDAY PUT IN A SLIGHT CHANCE
WHICH WILL OF COURSE NOT SHOW UP IN THE TEXT. A BIT CONCERNED
ABOUT INCREASING MOISTURE FROM THE NORTHWEST WITH A SHORT WAVE
SHOWING UP IN THE NWLY FLOW ALOFT. INCREASED POPS TO CHANCE NRN
FRINGE FRIDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE AT THE SURFACE WILL BUILD TO THE EAST COAST BY
SATURDAY ALLOWING MOISTURE TO START TO CREEP BACK NORTH INTO THE
REGION WITH A LIGHT SOUTHERLY RETURN FLOW DEVELOPING. THE WESTERN
HALF OF THE FORECAST AREA WILL SEE AT LEAST A CHANCE OF
THUNDERSTORMS WITH SOME INSTABILITY AND SHORTWAVE ENERGY CONTINUING
TO ROUND THE UPPER LEVEL RIDGE. MODELS ARE IN FAIR AGREEMENT WITH
THE 00Z CYCLE IN SHOWING A STRONGER TROUGH ATTEMPTING TO DAMPEN THE
RIDGE OVER THE GREAT LAKES ON SUNDAY WHICH SHOULD YIELD BETTER
CHANCES OF SHOWERS AND THUNDERSTORMS. CONFIDENCE IS LOW IN TIMING
AND PATTERN EVOLUTION THAT FAR OUT SO WILL JUST CARRY A 30 POP FOR
NOW. TEMPERATURES WILL BE ABOVE NORMAL OVER THE WEEKEND WITH A
COOLING TREND FOR EARLY NEXT WEEK AS A COLD FRONT PUSHES SOUTH
ACROSS THE AREA.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE TODAY
AS THE ATMOSPHERE CONTINUES TO MOISTEN. EARLY MORNING HZ/BR ALSO
POSSIBLE 09-13Z WITH INCREASING DEWPOINTS. EARLY THIS MORNING WE
ARE WATCHING A COMPLEX OF THUNDERSTORMS OVER NE WISCONSIN WHICH
WILL TAKE AIM AT NRN OHIO AFTER 12Z. EXPECTING THIS COMPLEX TO
UNDERGO SOME WEAKENING AS IT APPROACHES. REMNANTS OF THIS FEATURE
WILL RESULT IN ADDITIONAL STORM DEVELOPMENT EARLY THIS AFTERNOON
AND HAVE INCLUDED A VCTS IN ALL SITES. TIMING REMAINS IN QUESTION
BUT EXPECT PRETTY GOOD CHANCES FOR A THUNDERSTORM AT SOME POINT
THIS AFTERNOON...ESPECIALLY AT CLE/MFD/CAK/YNG WITH THE POTENTIAL
FOR SOME THUNDERSTORMS TO BE STRONG TO SEVERE.
MODELS ARE IN PRETTY GOOD AGREEMENT THAT WE ARE LOOKING FOR ANOTHER
ROUND OF THUNDERSTORMS TOWARDS THE END OF THE TAF CYCLE (04-12Z) AS
LOW PRESSURE TRACKS THROUGH THE SOUTHERN GREAT LAKES. THESE
THUNDERSTORMS COULD ONCE AGAIN BE STRONG WITH HEAVY RAINFALL
POSSIBLE.
OUTLOOK...MVFR PROBABLE WITH SHRA/TSRA BR TUESDAY AFTERNOON THROUGH
WEDNESDAY.
&&
.MARINE...
WINDS ON LAKE ERIE WILL MAINTAIN A WESTERLY COMPONENT AT 15 KNOTS OR
LESS TODAY. MULTIPLE ROUNDS OF THUNDERSTORMS ARE POSSIBLE ON THE
LAKE OVER THE NEXT 24 HOURS...ESPECIALLY TONIGHT AS A WAVE OF LOW
PRESSURE MOVES THROUGH THE SOUTHERN GREAT LAKES. THE AREA IS IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS THROUGH TONIGHT. THIS SYSTEM
WILL PULL A COLD FRONT SOUTH ACROSS THE LAKE BEHIND IT ON WEDNESDAY
WITH WINDS SHIFTING TO THE NORTH AT 10-15 KNOTS INTO THURSDAY.
THE NORTHERLY FLOW WILL RESULT IN SOME INCREASE IN WAVE CONDITIONS
IN THE NEARSHORE WATERS AS WAVES BUILD TO 1 TO 3 FEET ON THURSDAY.
HIGH PRESSURE WILL LIGHT WINDS AND WAVES WILL RETURN ON FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
401 AM EDT TUE AUG 27 2013
.SYNOPSIS...
WEAK SHORTWAVES CROSSES TODAY...UNDER NORTHWEST FLOW ALOFT. COLD
FRONT CROSSES WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE VISITS
BRIEFLY FRIDAY BEFORE PATTERN REPEATS.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH LEVEL CLOUDS ASSOCIATED WITH A DYING MCS ACROSS LAKE MICHIGAN
WILL COVER THE AREA THIS MORNING. NORTHWEST FLOW ALOFT...AND
EMBEDDED SHORTWAVES ARE EVIDENT IN VORT MAX FIELD ON H5 CHARTS.
ALTHOUGH IT LOOKS LIKE CONVECTIVE FEEDBACK...PIECES OF ENERGY
LOOKS REAL ACTING AS FORCING MECHANISMS.
THE HRRR MODEL BRINGS REMNANTS OF GREAT LAKES MCS OVER CKB...EKN
AND NORTHEAST MOUNTAINS THIS AFTERNOON. ANOTHER SHORTWAVE IS
EVIDENT IN H5 CHARTS APPROACHING THE AREA FROM THE NORTHWEST
WEDNESDAY.
NAM AND RUC MODELS SUGGEST AFTERNOON AND EVENING CONVECTION IN QPF
AND SFC CAPE FIELDS ALTHOUGH THE LATER LOOKS OVERDONE BY THE NAM
WITH DEWPOINTS IN THE LOW TO MID 70S. AN AREA OF DEEP LAYERED
SHEAR MOVES INTO SOUTHEAST OH AND PORTIONS OF WV THIS AFTERNOON.
EXPECT CONVECTIVE INITIATION WITH FEW STORMS BUT DO NOT EXPECT
THEM TO BECOME SEVERE.
CODED SKY AND POP GRIDS PER LATEST SATELLITE AND RADAR IMAGES. MID
LEVEL CLOUDS ADVECTING FROM THE NORTHWEST ACROSS SOUTHEAST OHIO
SITES SUCH AS PKB AND HTS EARLY THIS MORNING.
USED THE CONS MOS FOR TEMPERATURE THROUGH THE PERIOD.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ACTIVE WEATHER MAINLY THE FIRST HALF OF THE SHORT TERM PERIOD...WITH
PRECIP CHANCES AND POSSIBLE SUBSEQUENT HYDRO ISSUES PRIMARILY WED
AND WED NIGHT.
WEDNESDAY...AREA REMAINS UNDER NORTHWEST FLOW ALOFT WHILE AT THE SFC
SOUTHWEST WINDS IN PLACE. THOUGH DIFFS EXIST WITH STRENGTH AND
PLACEMENT...CONSENSUS OF NWP OUTPUT IS IN FAIRLY DECENT AGREEMENT
DRAGGING A COUPLE OF VORT MAXES ACROSS THE NORTHEASTERN ZONES FROM
NW TO SE ON WED. FIRST RIPPLE PUSHES INTO THE AREA RIGHT AROUND 12Z
WED AND OVER THE CENTRAL PART OF THE AREA BY 18Z WED. APPEARS THE
BEST OVERALL MOISTURE DEPTH NOT REALLY CO-LOCATED WITH BEST OVERALL
FORCING INITIALLY...WITH THE BEST MOISTURE OVER THE NE ZONES AND
BETTER DYNAMIC FORCING STILL TO THE WEST AND NORTHWEST AT 12Z WED.
HOWEVER OMEGA FIELDS INDICATE AMPLE LIFT THROUGH A DEEP LAYER ACROSS
THE NE ZONES AND WITH PLENTY OF MOISTURE IN PLACE WILL CONTINUE
CATEGORICAL POPS NE ZONES AT THE OUTSET. EXPECT SHOWERS AND
THUNDERSTORMS TO QUICKLY RAMP UP ACROSS THE NORTH AND NW ZONES AS
WELL DURING THE MORNING HOURS WITH THE APPROACH OF THE
AFOREMENTIONED VORT MAX AND ITS ASSOC LIFT...AS WELL AS LARGE SCALE
FORCING FOR ASCENT. BY THE AFTERNOON HOURS THE NEXT VORT MAX ON
NORTHWEST FLOW ALOFT PUSHES INTO THE NW ZONES BY 00Z THU. MODELS
STILL DIFFER ON THE PLACEMENT OF THE ASSOC SFC LOW...ALTHOUGH THEY
ARE TRYING TO COME CLOSER TOGETHER. STILL...LATEST NAM DEPICTS SFC
LOW STILL WELL WEST NEAR CINCINNATI AT 00Z THU WHILE OP GUIDANCE HAS
IT FURTHER EAST/NORTHEAST IN THE AREA OF OUR SE OHIO ZONES. GEFS
MEAN AND ITS MEMBERS SUPPORT THE FURTHER EAST SOLN AS DOES THE SREF
MEAN AND THUS WILL LEAN THE FORECAST IN THIS DIRECTION...WITH THE
LOW AND FRONT ENTERING INTO NW ZONES BY 00Z THU. ALL IN ALL WILL
CONTINUE TO TREND HIGHEST POPS FROM THE NE ZONES TOWARDS THE CENTRAL
AND SOUTHERN ZONES BY 00Z THU. EXPANDED THE COVERAGE OF CATEGORICAL
POPS TO INCLUDE GENERALLY LOCATIONS ALONG AND NORTHEAST OF A
BKW-CRW-PERRY COUNTY OH LINE AS IN THE END MOST IF NOT ALL OF THOSE
LOCATIONS SHOULD SEE SOME MEASURABLE RAINFALL BY DAY/S END ON
WEDNESDAY...THOUGH PINPOINTING THE TIMING ISN/T QUITE SO
STRAIGHTFORWARD. QPF AMOUNTS STILL RUNNING AROUND 0.75IN TO
1.00IN...AND WITH 3-HR FFG GUIDANCE AROUND 2 INCHES THERE IS CONCERN
FOR THE POSSIBILITY OF FLASH FLOODING. STILL NOT QUITE ENOUGH
CONFIDENCE TO ISSUE A WATCH AT THIS POINT AND WILL LET THE DAYSHIFT
TAKE ONE MORE LOOK AT IT. WILL CONTINUE HYDRO CONCERN MENTION
HOWEVER IN HWO AND DID GO AHEAD AND INCLUDE HEAVY RAIN WORDING IN
THE WX GRIDS WED.
PRECIP EXPECTED TO COME TO AN END FROM NW TO SE OVERNIGHT WED NIGHT
AS THE FRONT SWEEPS ACROSS THE AREA. MOST LOCATIONS WILL BE DRY ON
THURSDAY WITH THE FRONT WELL EAST OF THE AREA UNDER A PARTLY CLOUDY
SKY AND HIGHS GENERALLY IN THE MID 80S FOR LOWLAND LOCATIONS. WILL
KEEP INHERITED SLIGHT CHANCE AND LOW CHANCE POPS FOR THE
EAST/SOUTHEAST HIGH TERRAIN WITH A DECENT SLUG OF LLVL MOISTURE
REMAINING ALONG WITH SFC CONVERGENCE ON THE RIDGETOPS PROGGED.
THURSDAY NIGHT ALL LOCATIONS SHOULD DRY OUT WITH THE LOSS OF DAYTIME
HEATING. SFC HIGH PRESSURE CONTINUES TO MOVE EASTWARD AWAY FROM THE
AREA WITH RETURN SOUTHEAST FLOW SETTING UP. THIS...ALONG WITH
ANOTHER S/W TROUGH AND ASSOC VORT MAX MOVING INTO THE NORTHERN ZONES
BY AND AFTER 06Z FRI LENDS SOME POTENTIAL FOR LIGHT SHOWER
REDEVELOPMENT ON THE EAST SLOPES TOWARDS THE DAWN HOURS FRIDAY
MORNING. WILL LEAVE FORECAST DRY FOR NOW.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
GENERALLY FOLLOWED HPC IN EXTENDED WHICH WILL FEATURE QUIETER AND
DRIER WX DESPITE CONTINUING NW FLOW ALOFT. TEMPS RUNNING IN MID
80S AND LOWS GENERALLY IN 60S. GUIDANCE CONT TO RUN ON WARM
SIDE...AS HAS BEEN THE CASE MUCH OF THIS SUMMER. THINK WITH WET
GROUNDS THIS SEASON...FELT HEDGING A LITTLE BELOW GUIDANCE WAS
WARRANTED.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS BECOMING MVFR AT MOST PLACES PER BOUNDARY LAYER
FLOW FROM 10-15 KNOTS PREVENTING FOG FORMATION. THE EXCEPTION WILL
BE EKN...AND OTHER PROTECTED VALLEYS WHICH COULD EXPERIENCE DENSE FOG
FOR IFR CONDITIONS FROM 09-12Z.
RADAR IMAGES SHOW A WEAK LINE OF LIGHT SHOWERS MOVING SOUTH ACROSS
SOUTHEAST OH. THESE RAIN ACTIVITY SEEMS TO BE DIMINISHING AND
DYING WHILE WEAKLY REDEVELOP ALONG A DEFORMATION ZONE. DO NOT
EXPECT MUCH IMPACT WITH THIS FEATURE. AN ASSOCIATED LOW TO MID
STRATUS DECK WITH LIGHT RAIN SHOWERS COULD PROVIDE BRIEF PERIODS
OF MVFR/IFR ALONG THROUGH 09-12Z MAINLY HTS AND PKB.
RECOGNIZE NORTHWEST FLOW AND EMBEDDED SHORTWAVES AT H5 PATTERN
TODAY. EXPECT SERIES OF THUNDERSTORM COMPLEXES DEVELOPING AND
SPREADING SOUTHEAST DURING THE AFTERNOON AND EVENING PERIODS.
INCLUDED VCTS AT THE END OF TAF.
BKW REMAINS AMD NOT SKED ON ACCOUNT OF COMMUNICATION ISSUES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY
THIS AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 08/27/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY L L L L L H M M H H H H
HTS CONSISTENCY L L L L L M H H H H H H
BKW CONSISTENCY M M M M M H H M M M M M
EKN CONSISTENCY L L L L L H H M M H H H
PKB CONSISTENCY L L L L L H H H H H M H
CKB CONSISTENCY L L L L L M H H H H M H
AFTER 06Z WEDNESDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS TUESDAY AND WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KMC/30
NEAR TERM...ARJ
SHORT TERM...30
LONG TERM...30
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
333 AM EDT TUE AUG 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE SOUTHEASTERN STATES THE FIRST
HALF OF THE WEEK. MEANWHILE A WEAK FRONT WILL SAG SOUTH ACROSS
THE EASTERN GREAT LAKES THIS EVENING. AN AREA OF LOW PRESSURE
WILL MOVE EAST ACROSS THE LAKES ON TUESDAY NIGHT AND DRAG A COLD
FRONT SOUTH ACROSS THE AREA ON WEDNESDAY. HIGH PRESSURE WILL
RETURN TO THE AREA FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
WIDELY SCATTERED SHOWERS ACROSS THE AREA EARLY THIS MORNING BUT
MOSTLY WEST FROM FDY AREA TO MNN MOVING SOUTH. MAIN ISSUE FOR
TODAY WILL BE THE MCS MOVING SOUTHEAST THROUGH WI. CIRRUS WILL
MOVE INTO NWRN OHIO BY 4 TO 5AM WILL HRRR BRINGING DYING COMPLEX
INTO THE AREA 12-15Z. BROUGHT LIKELY POPS TO THE AREA FROM KCLE TO
KTOL BY 15Z WITH CHANCE POPS ELSEWHERE. INCREASED POPS TO LIKELY
SOUTHEAST AS SYSTEM DROPS SOUTHEAST THROUGH THE AREA. THROUGH THE
AFTERNOON DROPPED POPS BACK TO CHANCE.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
TONIGHT FOLLOWED SREF/NAM BLEND WHICH SHOWS A DEVELOPING OR
POSSIBLY ONGOING CONVECTIVE SYSTEM TO OUR NORTHWEST THAT WILL DROP
ACROSS THE AREA THROUGH THE EVENING AND EARLY OVERNIGHT HOURS.
WENT A BIT AGGRESSIVE ON POPS WITH CATEGORICAL POPS ACROSS A LARGE
PORTION OF THE AREA. WILL CONTINUE THIS INTO EARLY WEDNESDAY AS A
WEAK COLD FRONT DROPS THROUGH THE AREA BEFORE DROPPING BACK TO
LIKELY/CHANCE DURING THE AFTERNOON. WEDNESDAY NIGHT AND THURSDAY
DRIER MORE STABLE AIR MOVES IN FROM THE NORTH BEHIND THE COLD
FRONT. CONTINUE DRY THURSDAY NIGHT. FRIDAY PUT IN A SLIGHT CHANCE
WHICH WILL OF COURSE NOT SHOW UP IN THE TEXT. A BIT CONCERNED
ABOUT INCREASING MOISTURE FROM THE NORTHWEST WITH A SHORT WAVE
SHOWING UP IN THE NWLY FLOW ALOFT. INCREASED POPS TO CHANCE NRN
FRINGE FRIDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE AT THE SURFACE WILL BUILD TO THE EAST COAST BY
SATURDAY ALLOWING MOISTURE TO START TO CREEP BACK NORTH INTO THE
REGION WITH A LIGHT SOUTHERLY RETURN FLOW DEVELOPING. THE WESTERN
HALF OF THE FORECAST AREA WILL SEE AT LEAST A CHANCE OF
THUNDERSTORMS WITH SOME INSTABILITY AND SHORTWAVE ENERGY CONTINUING
TO ROUND THE UPPER LEVEL RIDGE. MODELS ARE IN FAIR AGREEMENT WITH
THE 00Z CYCLE IN SHOWING A STRONGER TROUGH ATTEMPTING TO DAMPEN THE
RIDGE OVER THE GREAT LAKES ON SUNDAY WHICH SHOULD YIELD BETTER
CHANCES OF SHOWERS AND THUNDERSTORMS. CONFIDENCE IS LOW IN TIMING
AND PATTERN EVOLUTION THAT FAR OUT SO WILL JUST CARRY A 30 POP FOR
NOW. TEMPERATURES WILL BE ABOVE NORMAL OVER THE WEEKEND WITH A
COOLING TREND FOR EARLY NEXT WEEK AS A COLD FRONT PUSHES SOUTH
ACROSS THE AREA.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE TODAY
AS THE ATMOSPHERE CONTINUES TO MOISTEN. EARLY MORNING HZ/BR ALSO
POSSIBLE 09-13Z WITH INCREASING DEWPOINTS. EARLY THIS MORNING WE
ARE WATCHING A COMPLEX OF THUNDERSTORMS OVER NE WISCONSIN WHICH
WILL TAKE AIM AT NRN OHIO AFTER 12Z. EXPECTING THIS COMPLEX TO
UNDERGO SOME WEAKENING AS IT APPROACHES. REMNANTS OF THIS FEATURE
WILL RESULT IN ADDITIONAL STORM DEVELOPMENT EARLY THIS AFTERNOON
AND HAVE INCLUDED A VCTS IN ALL SITES. TIMING REMAINS IN QUESTION
BUT EXPECT PRETTY GOOD CHANCES FOR A THUNDERSTORM AT SOME POINT
THIS AFTERNOON...ESPECIALLY AT CLE/MFD/CAK/YNG WITH THE POTENTIAL
FOR SOME THUNDERSTORMS TO BE STRONG TO SEVERE.
MODELS ARE IN PRETTY GOOD AGREEMENT THAT WE ARE LOOKING FOR ANOTHER
ROUND OF THUNDERSTORMS TOWARDS THE END OF THE TAF CYCLE (04-12Z) AS
LOW PRESSURE TRACKS THROUGH THE SOUTHERN GREAT LAKES. THESE
THUNDERSTORMS COULD ONCE AGAIN BE STRONG WITH HEAVY RAINFALL
POSSIBLE.
OUTLOOK...MVFR PROBABLE WITH SHRA/TSRA BR TUESDAY AFTERNOON THROUGH
WEDNESDAY.
&&
.MARINE...
WINDS ON LAKE ERIE WILL MAINTAIN A WESTERLY COMPONENT AT 15 KNOTS OR
LESS TODAY. MULTIPLE ROUNDS OF THUNDERSTORMS ARE POSSIBLE ON THE
LAKE OVER THE NEXT 24 HOURS...ESPECIALLY TONIGHT AS A WAVE OF LOW
PRESSURE MOVES THROUGH THE SOUTHERN GREAT LAKES. THE AREA IS IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS THROUGH TONIGHT. THIS SYSTEM
WILL PULL A COLD FRONT SOUTH ACROSS THE LAKE BEHIND IT ON WEDNESDAY
WITH WINDS SHIFTING TO THE NORTH AT 10-15 KNOTS INTO THURSDAY.
THE NORTHERLY FLOW WILL RESULT IN SOME INCREASE IN WAVE CONDITIONS
IN THE NEARSHORE WATERS AS WAVES BUILD TO 1 TO 3 FEET ON THURSDAY.
HIGH PRESSURE WILL LIGHT WINDS AND WAVES WILL RETURN ON FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1229 AM CDT TUE AUG 27 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH THURSDAY MORNING
CURRENT SURFACE ANALYSIS SHOWS A WEAK SURFACE LOW CENTERED OVER
THE KPIR AREA...WITH A WARM FRONT EXTENDING THROUGH KABR AND
K8D3 AND INTO WEST CENTRAL MINNESOTA. MODELS ARE SHOWING AN
ELONGATED AREA OF SHEARED OUT VORTICITY WORKING ITS WAY UP AND
OVER THE RIDGE. AREAS SOUTH OF THE WARM FRONT WILL LIKELY BE TOO
CAPPED FOR ANY CONVECTION TO DEVELOP /THE 700 MB TEMPERATURE OFF
THE MORNING KABR SOUNDING WAS 14 C/...HOWEVER CHANCES ARE DECENT
NORTH OF THE FRONT. THIS LOOKS LIKE IT WILL BE MAINLY OUR FAR
NORTHERN CWA TONIGHT. WITH OVER 2000 J/KG OF ML CAPE AND 40 TO 50
KTS OF 0-6 KM SHEAR PRESENT THIS EVENING...THERE IS CERTAINLY THE
CHANCE FOR ISOLATED SEVERE STORMS ALONG OUR NORTH. THE MOST RECENT
RUNS OF THE HRRR MODEL SEEM TO BE HANDLING THE SCENARIO
WELL...DEVELOPING STORMS ACROSS THE FAR NORTHWEST LATER THIS
AFTERNOON...AND THEN TRACKING ADDITIONAL ISOLATED SUPERCELLS ALONG
THE ND/SD BORDER BEFORE DROPPING THE CONVECTION INTO OUR FAR
NORTHEAST CWA LATER TONIGHT.
HOT TEMPERATURES CONTINUE TO AFFECT THE REGION THROUGH THE
REMAINDER OF THE SHORT TERM. MODEL 850 MB TEMPERATURES DO COOL
SLIGHTLY TUESDAY...WITH PERHAPS SOME DRIER AIR TRYING TO WORK INTO
THE REGION TUESDAY AND WEDNESDAY. HOWEVER...WITH MORE OF A NORTH
TO NORTHEAST SURFACE FLOW ON TUESDAY AND THEN WINDS SWITCHING BACK
TO THE SOUTHEAST ON WEDNESDAY...VERY SKEPTICAL ON DEWPOINTS DROPPING
MUCH LOWER THAN THE LOW TO MID 60S. HEAT INDICES DO APPEAR TO
REMAIN BELOW THE 100 DEGREE MARK HOWEVER. AS THE UPPER HIGH
WOBBLES AROUND THE CENTRAL PLAINS ADDITIONAL SHORTWAVE ENERGY IS
PROGGED TO MOVE ACROSS THE NORTHERN PLAINS. MODELS HAVE BEEN
FAIRLY CONSISTENT WITH THUNDERSTORM CHANCES ACROSS OUR WEST
TUESDAY NIGHT...AND THEN ACROSS OUR NORTH AND EAST ON WEDNESDAY
NIGHT AND THURSDAY MORNING. A 20 TO 30 KT LLJ IS ALSO PROGGED TO
SET UP ON WEDNESDAY NIGHT AND THURSDAY MORNING...ALTHOUGH AT THIS
POINT THE NOSE OF THE LLJ LOOKS TO BE PUSHING MORE INTO NORTH
DAKOTA...SO BETTER CHANCES STILL SEEM TO BE NORTH OF OUR CWA. WITH
ANY STORMS THAT CAN DEVELOP OVER THE NEXT COUPLE OF DAYS...ISOLATED
SEVERE STORMS ARE CERTAINLY POSSIBLE.
.LONG TERM...THURSDAY THROUGH MONDAY
THE UPPER RIDGE CONTINUES TO DOMINATE THE PATTERN AT THE START OF
THE EXTENDED. SAT/SUN THERE IS A SLIGHT FLATTENING OF THE RIDGE
SHOWN ON BOTH THE ECMWF AND THE GFS. HOWEVER BY MONDAY THE MODELS
DIVERGE WITH PLACEMENT OF THE RIDGE LEAVING FORECASTER CONFIDENCE
LOW OVER THE LABOR DAY WEEKEND.
MAIN CHALLENGE WILL BE DETERMINING TIMING AND PLACEMENT OF ANY WAVES
THAT RIDE OVER THE RIDGE. STUCK CLOSE TO ALLBLEND DUE TO
UNCERTAINTY AND CURRENTLY HAVE SOME POPS MENTIONED FOR THURSDAY
AND THEN AGAIN SAT/SUN. TEMPERATURES WILL BE VERY WARM WITH HIGHS
IN THE 90S AS LONG AS THE RIDGE HOLDS. WHEN IT FLATTENS OR MOVES
EAST...TEMPS SHOULD FALL ACCORDINGLY BACK CLOSER TO NORMAL.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
OTHER THAN POSSIBLE LATE NIGHT MVFR FOG AT KABR/KATY...VFR
CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH TUESDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SERR
LONG TERM...WISE
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 336 AM CDT TUE AUG 27 2013
AREA RADARS CONTINUE TO SHOW STORMS FORM OVER MN AND MOVE INTO/
THROUGH NORTHERN WI. SO FAR STORMS HAVE NOT TRAINED OVER SAME
LOCATION WITH HEAVY RAIN FALLING IN NARROW BANDS. STORMS NOW OVER
NW WI...TO MOVE INTO CWA AFT 10Z. WILL NEED TO BE WATCHED AS SHEAR
INCREASING OVER NORTHERN WI ATTM. STORMS NOT EXPECTED INTO FFA AREA
UNTIL 12Z OR AFTER...SO HAVE DECIDED TO DROP HEADLINE. MAIN ISSUE
OF THIS FORECAST IS PCPN TRENDS.
FORCING FOR STORMS OVERNIGHT FGEN/WAA SHIFTING EAST WITH 850 WINDS
BECOMING WESTERLY BY MORNING. TODAYS FORCING TO BE MORE TIED INTO
RIDGE RIDING DISTURBANCES AND LOCATION OF BOUNDARY. MODELS SUGGEST
BOUNDARY TO SHIFT SLOWLY SOUTH THROUGH CWA TODAY. HRRR NOT DOING
TO BAD ATTM...WITH CURRENT PCPN NORTH. HRRR TRENDS TO DIMINISH
PCPN DURING MORNING HOURS...THEN REDEVELOP OVER REGION FROM
MARINETTE TO TOMAHAWK BY MID AFTERNOON. AGAIN AREA IN SLIGHT RISK
FOR SEVERE WITH SIG INSTABILITY.
HIGH PRESSURE TO BUILD INTO STATE LATER TONIGHT AND WED...BRINGING A
BRIEF DRYING TREND.
TEMPS TODAY AGAIN HIGHLY DEPENDENT ON CLOUDS. WINDS BECOME A BIT
MORE ONSHORE TOO AS BOUNDARY SHIFTS SOUTH. HAVE TRENDED A BIT
COOLER NORTH AND FAR EAST...STAYING CLOSE TO YESTERDAYS READINGS.
AGAIN HEAT INDEX READINGS HIT 100 FOR COUPLE HOURS FAR SOUTHWEST
CWA. WILL STAY WITH SPS TO HIGHLIGHT AND NOT ISSUE ANY HEADLINE.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 336 AM CDT TUE AUG 27 2013
MDLS ARE IN GENERAL AGREEMENT ON THE LONG-RANGE MEAN FLOW ACROSS
THE CONUS WITH UPR TROFS JUST OFF THE WEST COAST AND WRN ATLANTIC
WITH AN UPR RDG SITUATED OVER THE CNTRL/SRN PLAINS. QUESTIONS
ARISE BY LATE IN THE WEEKEND WHETHER THE UPR RDG WL REMAIN
SOMEWHAT FLAT OR BUILD NWD THRU THE ROCKIES AS AN UPR TROF DIGS
TOWARD THE NE CONUS. AFTER A BRIEF RESPITE FROM THE HEAT/HUMIDITY
WED NGT/THU...RETURN FLOW MAKES A COMEBACK BRINGING PCPN CHCS BACK
TO THE REGION THU NGT/FRI WITH SEVERAL OTHER CHCS FOR PCPN THRU
THE UPCOMING WEEKEND.
NE WI TO REMAIN ON THE WRN FRINGE OF THE SFC HI THRU WED NGT...
THEREBY KEEPING WINDS LIGHT AND LEADING TO THE POTENTIAL OF MORE
FOG. THE EXACT EXTENT OF THE FOG IS A BIT UNCERTAIN AS MID AND UPR
LEVEL CLOUDS COULD BE MOVING INTO CNTRL WI AFTER MIDNGT AS WAA
BEGINS TO SPREAD NE FROM THE MIDWEST. HAVE KEPT FOG PATCHY FOR NOW
WITH MIN TEMPS RANGING FROM THE UPR 50S TO LWR 60S NORTH...60 TO
65 DEGS ELSEWHERE.
AS THE SFC HI DRIFTS TOWARD THE ERN GREAT LAKES ON THU...RETURN
FLOW SETS UP ACROSS WI WITH DEW POINTS STARTING TO CREEP UP ONCE
AGAIN. IN ADDITION...MDLS ARE SHOWING A SHORTWAVE TROF TOPPING THE
UPR RDG AND SLIDING E-SE TOWARD THE WRN GREAT LAKES BY LATE IN THE
DAY. BETWEEN THE LIFT FROM THE WAA AND THE START OF MID-LEVEL
FORCING FROM THE SHORTWAVE TROF...CANNOT RULE OUT A FEW SHWRS OR
TSTMS OVER CNTRL WI DURING THE AFTERNOON. AWAY FROM THE IMMEDIATE
LAKESHORE...EXPECT MAX TEMPS TO GENERALLY REACH THE LWR TO MID 80S.
THE SHORTWAVE TROF IS FCST TO MOVE SE INTO THE GREAT LAKES REGION
THU NGT AND HELP TO DRAG A WEAK FRONTAL BOUNDARY INTO NRN WI DURING
THE OVRNGT HOURS. WHILE INSTABILITY IS MARGINAL...SHEAR IS FAIRLY
STRONG TO SUSTAIN UPDRAFTS AND THERE IS A DIFFLUENT FLOW ALOFT
ADDING TO THE LIFT. PREFER TO GO WITH A MORE UNIFORM HI CHC POP
FOR NE WI...BUT BELIEVE THAT NRN PARTS OF THE STATE WOULD SEE
HIGHER QPF AMOUNTS AS FORCING A BIT STRONGER DUE TO THE PROXIMITY
OF THE SHORTWAVE TROF. THIS FRONTAL BOUNDARY WL SLOWLY SAG THRU WI
ON FRI...BUT BEGIN TO SLOW DOWN AS IT ENCOUNTERS THE EDGE OF THE
BROAD CNTRL/SRN PLAINS UPR RDG. A CONTINUED CHC OF SHWRS/TSTMS
ACROSS THE FCST AREA IS NECESSARY...ALTHO THE NORTH MAY SEE THE
PCPN COME TO AN END DURING THE AFTERNOON IF THE BOUNDARY CAN SLIP
FAR ENUF TO THE SOUTH. ANTICIPATED CLOUDS SHOULD HELP TO HOLD
TEMPS IN CHECK...BUT WITH 8H TEMPS STILL NEAR +20C...ANOTHER DAY
IN THE LWR TO MID 80S CAN BE EXPECTED.
THE MAIN QUESTION FOR THE FRI NGT/SAT TIME FRAME IS WHETHER THIS
BOUNDARY WL PUSH FAR ENUF SOUTH BEFORE STALLING TO AVOID THE
MENTIONING OF MORE PCPN. MDLS HAVE VARIOUS SOLUTIONS HERE...BUT
THE LATEST TRENDS DO SHOW THIS BOUNDARY SAGGING FAR ENUF TO AT
LEAST MINIMIZE THE PCPN CHCS OVER THE NORTH. NOT ENUF CONFIDENCE
TO COMPLETELY PULL THE POPS...BUT AT LEAST WL ATTEMPT TO TIER POPS
MORE FROM SOUTH TO NORTH.
A LOT OF UNCERTAINTY REMAINS FOR THE SUNDAY PERIOD AS THE ECMWF
BUILDS THE UPR RDG NWD THRU THE ROCKIES FASTER THAN THE OTHER
MDLS. THE ECMWF`S SOLUTION WOULD SEND A CDFNT THRU WI ABOUT 12
HOURS FASTER...THUS CLEARING THINGS OUT FOR SUNDAY AS OPPOSED TO A
SUNDAY FROPA ADVERTISED BY THE GFS/GEM. SINCE THIS IS MAJOR
PATTERN CHANGE...FULLY EXPECT THE MDLS TO WAFFLE ON TIMING OF THIS
FROPA...THUS HAVE FOLLOWED THE CONSENSUS MDL SOLUTION WHICH KEEPS
A LOW POP IN THE FCST THRU SUNDAY. A LARGE AREA OF HI PRES IS THEN
FCST TO BUILD INTO THE REGION FOR MON AND BRING COOLER/MUCH DRIER
AIR TO NE WI.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1049 PM CDT MON AUG 26 2013
MAINLY STRATIFORM TYPE PRECIPITATION WITH EMBEDDED
STORMS OVER NORTH CENTRAL WISCONSIN CONTINUES TO SPREAD SOUTHEAST
OVERNIGHT. SCATTERED MVFR CIGS AND VSBYS WITH SHOWERS AND STORMS
OVERNIGHT WITH PERHAPS POCKETS OF IFR CIGS LATE TONIGHT OVER NORTH
CENTRAL WISCONSIN. WITH THE FRONT STILL GRADUALLY DROPPING SOUTH
ON TUESDAY...SCATTERED MVFR CIGS AND VSBYS DUE TO CONVECTION WILL
CONTINUE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
316 AM CDT TUE AUG 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT TUE AUG 27 2013
..CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER
TROUGH JUST OFF THE PACIFIC NORTHWEST COAST AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUE TO ROTATE AROUND THE RIDGE...TRACKING FROM ARIZONA INTO THE
DAKOTAS AND THE FORECAST AREA. PRECIPITABLE WATER VALUES MAX OUT IN
THE 2-2.25 INCH RANGE FROM CENTRAL MN INTO NORTHERN WI PER RAP
ANALYSIS. CLUSTERS OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
MONSOONAL SHORTWAVES AS WELL AS 850MB-700MB MOISTURE TRANSPORT HAVE
BEEN TRACKING THROUGH THIS PRECIPITABLE WATER MAX. BLOWOFF FROM THIS
CONVECTION ENCOMPASSES MUCH OF THE FORECAST AREA. AIRMASS IS VERY
WARM ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THE 00Z MPX RAOB
REPORTED A 25C 850MB TEMP AND 27C 925MB TEMP...WHICH TRANSLATED TO A
HIGH YESTERDAY OF 97F AT MSP. BETWEEN THE HOT TEMPERATURES
YESTERDAY...THE BLOWOFF...A LIGHT SOUTHERLY BREEZE AND DEWPOINTS
HOLDING IN THE LOW 70S...TEMPERATURES HAVE STRUGGLED TO DROP THIS
MORNING. READINGS ARE STILL MAINLY BETWEEN 75 AND 80. SURFACE
PRESSURE ANALYSIS SHOWED LOW PRESSURE NEAR MONTEVIDEO MN...WITH A
WARM FRONT STRETCHING INTO TAYLOR COUNTY AND A COLD FRONT BACK INTO
CHAMBERLAIN SOUTH DAKOTA.
..HAZARDS..
1. HEAT. HAVE KEPT ALL GOING HAZARDS INTACT. CONSIDERED UPGRADING
FLOYD...CHICKASAW AND FAYETTE COUNTIES TO EXCESSIVE HEAT
WARNING...BUT HEAT INDICES APPEAR MARGINAL TO DO SO.
2. STORMS. SEVERE POTENTIAL...PARTICULARLY THIS AFTERNOON NORTH AND
EAST OF I-94.
3. FOG LATE TONIGHT...WHICH COULD END UP BEING DENSE...ESPECIALLY
WHERE IT RAINS.
..SYNOPTIC OVERVIEW..
THE SUBTROPICAL RIDGE OVER KANSAS AND MISSOURI IS PROGGED TO STAY
PUT THROUGH TONIGHT. HOWEVER...A CHANGE IN THE UPPER AIR PATTERN IS
TO HAVE SOME RIDGE BUILD NORTH TONIGHT INTO THE DAKOTAS. THIS...IN
TURN...HELPS TO TURN THE FLOW MORE NORTHWESTERLY OVER THE FORECAST
AREA. A SERIES OF MONSOONAL SHORTWAVES ROTATING AROUND THE RIDGE ARE
FORECAST TO COME THROUGH NORTHEASTERN PORTIONS OF THE FORECAST AREA
THROUGH TONIGHT...HELPING TO PUSH THE SURFACE LOW AND COLD FRONT
SOUTHEAST THROUGH THE ENTIRE AREA BY 12Z WEDNESDAY.
..DETAILS..
PRECIPITATION...WITH 850MB AND 700MB MOISTURE TRANSPORT FOCUSED INTO
THE AREA NORTHEAST OF I-94 THIS MORNING...THERE REMAINS POTENTIAL
FOR CONVECTION JUST FROM THIS THERMODYNAMIC FORCING. HOWEVER...THINK
THE GREATER POTENTIAL FOR CONVECTION WILL COME THIS AFTERNOON AS A
SHORTWAVE PRESENTLY WEST OF FARGO COMES THROUGH CENTRAL WISCONSIN AT
PEAK HEATING. VERY GOOD MODEL CONSENSUS FOR CONVECTION TO OCCUR
NORTHEAST OF I-94 IN THE AFTERNOON...WITH EVEN A POSSIBILITY OF IT
EXTENDING BACK TOWARDS LA CROSSE. THIS CONVECTION WILL SLIDE
SOUTHEAST OF THE AREA DURING THE EVENING...WITH ALL OF IT LIKELY OUT
BY 03Z. DRY CONDITIONS ARE EXPECTED ELSEWHERE DUE TO CAPPING AND
LIMITED CONVERGENCE ON THE COLD FRONT...AND DRY CONDITIONS ARE
ANTICIPATED ONCE THE FRONT PASSES AS SUBSIDENCE AND DRYING WORK IN.
SEVERE POTENTIAL...0-6KM SHEAR IS DECENT IN THE MORNING...35-45 KT
NORTHEAST OF I-94. HOWEVER...NOT ANTICIPATING MUCH OF THE MORNING
CONVECTION TO BE ABLE TO UTILIZE THIS SHEAR. DURING THE AFTERNOON
WHEN CAPE IS AT ITS HIGHEST...THE 0-6KM SHEAR IS WEAKENING TO 30-35
KT. NONETHELESS...WITH MLCAPES OF 2000-2500 FT COMBINING WITH THIS
SHEAR SHOULD ALLOW FOR SOME STORM ORGANIZATION...LIKELY IN THE FORM
OF MULTICELLS WITH A SUPERCELL POSSIBLE. FREEZING LEVELS UP NEAR
16000 FT SHOULD LIMIT HAIL...BUT CERTAINLY DAMAGING WINDS AND VERY
HEAVY RAIN ARE POSSIBLE GIVEN THE UNSEASONABLY WARM...MOIST
ENVIRONMENT.
HEAT...925MB TEMPERATURES TODAY ARE PROGGED VERY SIMILAR TO
YESTERDAY AHEAD OF THE COLD FRONTAL PASSAGE...RUNNING BETWEEN
27-29C. SO WE SHOULD SEE READINGS THAT ARE SIMILAR AS WELL. AROUND
CHARLES CITY THE READINGS APPROACH 30C...SO IT IS POSSIBLE THEY WILL
END UP A LITTLE WARMER.
LASTLY...A POTENTIAL ISSUE TO DEAL WITH LATE IN THE NIGHT IS FOG.
THE FRONT THAT COMES THROUGH TONIGHT IS QUITE SHALLOW AND STRUGGLES
TO GET THESE HIGHER DEWPOINTS OUT OF HERE. WITH COOLER AIR COMING IN
BEHIND THE FRONT AND LIGHT SURFACE WINDS...WE MAY END UP WITH SOME
SHALLOW FOG...PARTICULARLY SOUTHWEST OF I-94. SREF VISIBILITY PROGS
SHOW THIS NICELY. HAVE RAISED THE FOG COVERAGE AND WILL HAVE TO
WATCH FOR POSSIBLE DENSE FOG.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE AUG 27 2013
..HAZARDS..
1. HEAT. DEWPOINTS LOOK A LITTLE BIT HIGHER FOR WEDNESDAY...THOUGH
TEMPERATURES WILL NOT BE NEARLY AS WARM THE PAST FEW DAYS.
THEREFORE...HEAT INDICES ONLY TOP OUT IN THE 90S...JUST BELOW
ADVISORY CRITERIA. FARTHER AHEAD...AN ADVISORY IS LOOKING MORE
LIKELY FOR FRIDAY...PARTICULARLY NORTHEAST IOWA AND FAR SOUTHWEST
WI. NO ADVISORIES NEEDED NOW FOR THE WEEKEND.
..SYNOPTIC OVERVIEW..
27.00Z MODEL GUIDANCE IN GOOD AGREEMENT SHOWING THAT THE SUBTROPICAL
RIDGE OVER KANSAS AND MISSOURI WILL RETROGRADE WESTWARD INTO THE
FOUR CORNERS REGION BY SATURDAY. THE LAST COUPLE OF DAYS MODELS HAD
SUGGESTED THAT THE RIDGE WOULD HEAD BACK EAST. HOWEVER...THIS IS NOW
DELAYED BECAUSE OF A SHORTWAVE TROUGH COMING OUT OF SOUTHWEST CANADA
ON FRIDAY THAT ENDS UP DIGGING INTO THE GREAT LAKES REGION ON
SUNDAY. THE 26.00Z ECMWF WAS FIRST TO SHOW THIS AND NOW ALL MODELS
HAVE CAPTURED ONTO THE IDEA. THE ONLY QUESTION NOW IS TIMING AND
AMPLIFICATION OF THIS TROUGH...WHICH THERE IS A DECENT SPREAD ON
COME SUNDAY.
..DETAILS..
WITH THE FRONTAL BOUNDARY SOUTH OF THE AREA ON WEDNESDAY AND HIGH
PRESSURE IN PLACE...HAVE CONTINUED THE DRY FORECAST. AS MENTIONED IN
THE HAZARDS SECTION...HIGHER DEWPOINTS DOES RAISE CONCERN FOR
EXTENSION IN THE HEAT ADVISORY. HOWEVER...925MB TEMPS OF 25-27C WILL
RESULT IN COOLER HIGHS...KEEPING HEAT INDICES BELOW ADVISORY LEVEL.
A SERIES OF SHORTWAVES ARE PROGGED TO COME ACROSS THE NORTHERN
PLAINS AND INTO THE NORTHERN GREAT LAKES REGION WEDNESDAY NIGHT
THROUGH FRIDAY. THE SHORTWAVES WEDNESDAY NIGHT AND THURSDAY ARE
PROGGED TO HELP BRING THE COLD FRONT BACK TOWARDS US...AND
ISENTROPIC LIFT/MOISTURE TRANSPORT OVER THE FRONT RESULTS IN CONCERN
FOR CONVECTION. THE GREATEST CHANCES FOR CONVECTION WEDNESDAY NIGHT
AND THURSDAY WILL TRACK JUST NORTH OF THE AREA...CLOSER TO THE
SHORTWAVES...BUT THE ISENTROPIC LIFT COULD SPREAD SOME SHOWERS AND
THUNDERSTORMS DOWN INTO THE FORECAST AREA...ESPECIALLY WEST OF THE
MS RIVER AND OVER NORTH CENTRAL WISCONSIN. HAVE CONTINUED 20-30
PERCENT CHANCES. THESE CHANCES GRADUALLY ENCOMPASS MORE OF THE AREA
HEADING INTO THURSDAY NIGHT AND ESPECIALLY FRIDAY. ON FRIDAY...
MODELS ARE IN GOOD AGREEMENT SHOWING A SHORTWAVE COMING THROUGH
CENTRAL MN AND SOUTHEAST INTO THE FORECAST AREA AT THE TIME OF PEAK
HEATING. 0-6KM SHEAR ONLY PROGGED 20-25 KT...SO NOT THINKING SEVERE
AT THIS TIME. TEMPERATURES WILL COOL DOWN BRIEFLY ON THURSDAY
BETWEEN CLOUDS/POTENTIAL CONVECTION AND 925MB TEMPS OF 22-26C.
HOWEVER...TEMPERATURES LOOK TO SHOOT BACK UP ON FRIDAY AHEAD OF THAT
SHORTWAVE COMING THROUGH. COOLING WILL OCCUR FRIDAY NIGHT WITH
PASSAGE OF THE SHORTWAVE TROUGH.
HEADING INTO LABOR DAY WEEKEND...WARM AIR COULD TRY TO SURGE BACK
INTO THE AREA ON SATURDAY...AHEAD OF THE MORE POTENT SHORTWAVE
TROUGH CROSSING SOUTH CENTRAL CANADA. ONLY HAVE SOME VERY LOW
CHANCES OF PRECIPITATION IN...MAINLY TOWARDS CENTRAL WISCONSIN WHERE
ISENTROPIC LIFT LOOKS GREATEST. BIGGEST CONCERN COMES SUNDAY AND
MONDAY WITH HOW MUCH COLD AIR COMES IN BEHIND THE COLD FRONT
ASSOCIATED WITH THE SHORTWAVE TROUGH...ALONG WITH TIMING TOO. 27.00Z
ECMWF IS VERY AGGRESSIVE DIVING 925MB TEMPS DOWN TO 6C BY 12Z
MONDAY. COMPARE THIS TO THE 27.00Z GFS WHICH ARE 16-20C...DRAMATIC
DIFFERENCE. THUS...TEMPERATURE FORECASTS ARE LOW CONFIDENCE. GIVEN
THE COOLER SIGNAL IN THE ECMWF...FELT IT WAS APPROPRIATE TO LOWER
HIGHS...LOWS AND DEWPOINTS FOR SUNDAY THROUGH MONDAY NIGHT ABOUT 5
OR SO DEGREES FROM THE PREVIOUS FORECAST. RAIN CHANCES LOOK MINIMAL
FOR SUNDAY THROUGH MONDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1123 PM CDT MON AUG 26 2013
A WARM FRONT JUST NORTH OF THE I-94 CORRIDOR WILL KEEP KRST/KLSE
IN MORE OF A CAPPED ENVIRONMENT THROUGH TUESDAY...MEANING THAT
WARM AIR ALOFT SHOULD INHIBIT CONVECTION. VFR CONDITIONS EXPECTED AS A
RESULT WITH JUST SOME MID-LEVEL CLOUD COVER FROM CONVECTIVE
DEBRIS TO THE NORTH. OTHERWISE...SURFACE WINDS EXPECTED TO REMAIN
OUT OF THE SOUTH- SOUTHWEST AT 10-15KT WITH SOME LATE MORNING
THROUGH AFTERNOON GUSTINESS UP AROUND 20KT OR SO. A WEAK COLD
FRONT IS THEN EXPECTED TO SLIP INTO THE AREA TUESDAY EVENING. ANY
CONVECTION ASSOCIATED WITH THIS FRONTAL PASSAGE IS EXPECTED TO
REMAIN EAST OF THE MISSISSIPPI RIVER AND MAINLY ALONG AND NORTH OF
I-94. KLSE COULD GET BRUSHED BY SOME OF THIS SHRA/TS
ACTIVITY...BUT CONFIDENCE IS VERY LOW AT THIS POINT SO WILL LEAVE
OUT FOR NOW. OTHERWISE...LOOK FOR A WINDSHIFT FROM THE SOUTHWEST
TO THE NORTHWEST IN THE 23-01Z TIME FRAME AT KRST/KLSE. VFR
CONDITIONS ARE EXPECTED TO PREVAIL THROUGH TUESDAY EVENING.
&&
.CLIMATE...
ISSUED AT 334 PM CDT MON AUG 26 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR WIZ017-029-034-
042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR WIZ032-033-
041.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR MNZ086-087-094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR MNZ079-088-
096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
850 AM MST TUE AUG 27 2013
&&
.SYNOPSIS...
OVERALL PRECIPITATION CHANCES WILL DECREASE SLIGHTLY TODAY AND
WEDNESDAY AS DRIER AIR ATTEMPTS TO SETTLE OVER THE REGION FROM THE
EAST....HOWEVER RESIDUAL MOISTURE WILL STILL SUPPORT A FEW STORMS.
A LARGER DISTURBANCE WILL MOVE INTO THE REGION AND REESTABLISH MORE
EXTENSIVE THUNDERSTORM ACTIVITY THURSDAY AND FRIDAY. WITH THE
EXCEPTION OF SOME WARMING TO NEAR AVERAGE LEVELS THE NEXT COUPLE
DAYS...TEMPERATURES WILL GENERALLY REMAIN BELOW THE SEASONAL NORMAL.
&&
.DISCUSSION...
A MUCH QUIETER MORNING ACROSS OUR CWA WHEN COMPARED TO ALL OF
YESTERDAY/S ACTIVITY OVER SOUTH-CENTRAL ARIZONA. THE DISTURBANCE
THAT TRIGGERED THE STORMS YESTERDAY EVENING HAS NOW MOVING RAPIDLY
NORTHWARD INTO UTAH...WITH JUST SOME LEFT-OVER SHOWERS AND A FEW TS
BEING DETECTED ON RADAR OVER THE WESTERN 1/2 OF THE FLAGSTAFF CWA.
BASED ON CURRENT OBSERVATIONS AND RADAR TRENDS...HAVE REDUCED POPS
TO JUST SLIGHT CHANCE ONES OVER LA PAZ AND EXTREME NORTHWEST
MARICOPA COUNTIES FOR THE REMAINDER OF THE MORNING AND EARLY
AFTERNOON HOURS.
GIVEN THE LAST FEW RUNS OF THE HIGH-RES HRRR MODEL...WHICH DID VERY
WELL FORECASTING YESTERDAY/S CONVECTIVE ACTIVITY...AND NOW IS
FORECASTING VERY LITTLE...OR NO CONVECTIVE DEVELOPMENT FOR TODAY AND
TONIGHT...THERE IS NOW EVEN GREATER CONFIDENCE THAT THIS
AFTERNOON/EVENING SHOULD BE A PRETTY QUIET ONE. THUS...HAVE LEFT THE
SHORT-TERM GRIDS FOR THE AFTERNOON/EVENING ALONE...WHICH ARE
FORECASTING JUST A SLIGHT CHANCE FOR STORMS OVER MOST AREAS OF OUR
CWA.
&&
.PREVIOUS DISCUSSION...
EARLY THIS MORNING...AN EASTERLY WAVE WAS PROPAGATING NORTH INTO
SWRN NEW MEXICO WITH THE RIGHT REAR JET DIVERGENCE FIELD LIFTING
INTO NRN ARIZONA. THE PLUME OF DEEP TROPICAL MOISTURE OVER CNTRL/WRN
ARIZONA WAS BECOMING PINCHED BY ADVECTION OF DRIER MID LEVEL AIR
FROM BOTH THE EAST AND WEST PER WV IMAGERY. THIS SCENARIO WAS
ALREADY BEING SEEN IN 00Z/03Z REGIONAL SOUNDING DATA WITH MIXING
RATIOS IN THE H7-H8 LAYER FALLING BELOW 10 G/KG. DESPITE THIS...THE
COMBINATION OF SFC HEATING...MOISTURE ALOFT...AND FAVORABLE ASCENT
SUPPORTED THUNDERSTORM FORMATION ALONG OUTFLOWS AT LOWER ELEVATIONS
THROUGH THE EVENING HOURS.
OPERATIONAL AND HI RES MODELS ONCE AGAIN INDICATE LESSER ACTIVITY
THIS AFTERNOON AND EVENING IN THE WAKE OF THE WAVE PASSAGE AND
GENERAL DRYING TREND THROUGH THE ATMOSPHERIC COLUMN. OF COURSE...THE
SAME 00Z MODELS YESTERDAY FAILED TO CAPTURE THE EXTENT OF ACTIVITY
LAST EVENING...AND IT WASNT UNTIL 12Z INITIALIZATIONS THAT A
SOMEWHAT BETTER OUTCOME WAS ADVERTISED. WITH RESIDUAL MOISTURE LEFT
IN BOTH THE LOWER BOUNDARY LAYER AND MID LEVELS...STILL CANNOT
DISCOUNT ANY PULSING STORM ACTIVITY TODAY...THOUGH MORE ORGANIZED OR
PERSISTENT ACTIVITY SHOULD BE LACKING. OTHERWISE...TEMPERATURES
SHOULD REBOUND TO NEAR AVERAGE LEVELS THIS AFTERNOON...WITH THE
FORECAST TAILORED TOWARDS RAW MODEL CONSENSUS.
OVERALL MOISTURE PROFILES WILL ONLY CHANGE SLIGHTLY WEDNESDAY...WITH
SFC-H7 MIXING RATIOS IN THAT MARGINALLY SUPPORTIVE 10-12 G/KG RANGE.
HOWEVER...BETTER DYNAMICAL ASCENT ON THE LEADING EDGE OF AN EASTERLY
WAVE AND A CORRESPONDING RENEWED PUSH OF DEEPER MOISTURE WILL BEGIN
TO ENTER SERN ARIZONA...HELPING ORGANIZE MORE ROBUST THUNDERSTORM
DEVELOPMENT. BIGGEST QUESTION REMAINS WHETHER THE ATMOSPHERE AT
LOWER ELEVATIONS OF CNTRL ARIZONA WILL ALLOW FOR MORE THAN DECAYING
OUTFLOWS. KEPT RELATIVELY MODEST POPS AWAITING THE MAIN BRUNT OF THE
WAVE AND MOISTURE FLUX BEYOND WEDNESDAY EVENING.
OPERATIONAL MODELS CONTINUE TO SUGGEST A VERY WELL DEFINED
EASTERLY WAVE...PRONOUNCED UPPER DIFLUENCE...AND THICK TROPICAL
MOISTURE PROGRESSING INTO THE FORECAST AREA THURSDAY AND FRIDAY.
PARTIALLY THE REMNANT CIRCULATION OF OLD ATLANTIC TROPICAL CYCLONE
FERNAND COMBINED WITH A SOUTHEAST PACIFIC MOISTURE
TAP...PRECIPITATION MAY COME IN WAVES WITH AN INITIAL BAND OF
ELEVATED LIFT PRECEDING THE WAVE...THEN DIURNAL CONVECTIVELY
GENERATED STORMS. TIMING AND LOCATION UNCERTAINTIES STILL PRECLUDE A
MUCH STRONGER POP MENTION FOR ANY SPECIFIC TIME FRAME...HOWEVER
MODEL SOUNDING FORECASTS OF PROLONGED PERIODS OF PWATS GREATER THAN
2.0 INCHES AND BOUNDARY LAYER MIXING RATIOS AOA 15 G/KG SUGGEST SOME
AMOUNT OF PRECIPITATION WILL BE INEVITABLE SOMETIME DURING THE
THURSDAY/FRIDAY TIME FRAME ACROSS MUCH OF THE CWA.
FORECAST UNCERTAINTY BEGINS TO GROW OVER THE WEEKEND...AS ECMWF
FORECASTS BEGIN TO SCOUR OUT SOME MOISTURE WHILE RETROGRADING
RIDGING AND SUBSIDENCE INTO THE REGION...WHILE GFS FORECASTS
MAINTAIN WEAK PERTURBATIONS AND FAVORABLE MOIST VERTICAL MOTION
PROFILES. EITHER SCENARIO APPEARS EQUALLY LIKELY AT THIS TIME...AND
COULD NOT JUSTIFY ADVERTISING A FORECAST TERRIBLY FAR FROM
CLIMATOLOGY GIVEN THE OVERALL UNCERTAINTY AND LOWER FORECAST
CONFIDENCE.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
BROKEN MID AND HIGH CLOUDS WILL GRADUALLY THIN AND BECOME MORE
SCATTERED THROUGHOUT THE MORNING HOURS. WINDS ARE EXPECTED TO
INCREASE OUT OF THE SOUTHEAST BY MID TO LATE MORNING AND BECOME
GUSTY AT TIMES BEFORE DIMINISHING LATE THIS AFTERNOON. THERE WILL
STILL BE A POSSIBILITY OF ISOLATED SHOWERS AND THUNDERSTORMS LATE
THIS AFTERNOON AND EVENING...BUT DEFINITELY LESSER CHANCES THAN
YESTERDAY.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FEW TO SCATTERED MID AND HIGH LEVEL CLOUDS ARE EXPECTED THROUGH THE
TAF PERIOD WITH WINDS LESS THAN 10 KNOTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
ANOTHER ACTIVE MONSOON PERIOD IS EXPECTED FROM THURSDAY ONWARD INTO
THE WEEKEND AS DEEP SOUTHERLY FLOW IMPORTS COPIOUS MOISTURE INTO THE
REGION...WITH EMBEDDED WEATHER DISTURBANCES HELPING TO ENHANCE
CONVECTIVE ACTIVITY...WITH A GOOD CHANCE OF WIDESPREAD WETTING RAINS
ACROSS THE ENTIRE DESERT SOUTHWEST. MINIMUM HUMIDITY VALUES ARE
EXPECTED TO ONLY FALL INTO THE 30 TO 40 PERCENT RANGE ACROSS THE
LOWER DESERTS...AND INTO THE 40 TO 55 PERCENT RANGE ACROSS THE
HIGHER ELEVATIONS EACH DAY...WITH EXCELLENT OVERNIGHT RECOVERIES.
THUNDERSTORM ACTIVITY WILL DECREASE SOMEWHAT ON MONDAY AS STRONG
RIDGING BEGINS TO BUILD IN FROM THE EAST. WINDS ARE EXPECTED TO
REMAIN ON THE LIGHT SIDE THROUGH THE PERIOD...EXCEPT NEAR
THUNDERSTORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/MO
AVIATION....KUHLMAN
FIRE WEATHER...PERCHA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
912 AM MDT TUE AUG 27 2013
.UPDATE...FORECAST LOOKS ON TRACK WITH SOMEWHAT LOWER
PRECIPITABLE WATER BUT HIGHER CAPES OFF 500-1000 J/KG. THE 12Z
DENVER SOUNDING DOES SHOW A RATHER STRONG SUBSIDENCE INVERSION
NEAR 520 MB...BUT WITH SUFFICIENT HEATING AND LOW LEVEL MOISTURE
WE SHOULD BE ABLE TO POP THROUGH THE CAP. HIGHEST COVERAGE OF
STORMS WILL UNDOUBTEDLY BEING ALONG THE FRONT RANGE
MOUNTAINS/FOOTHILLS... WITH CHANCES DECREASING RATHER QUICKLY TO
THE EAST. BEST CHANCE OF ANY STORMS MOVING OFF THE FOOTHILLS WOULD
BE FROM THE WESTERN SUBURBS OF DENVER TOWARD FORT COLLINS AND
NORTHERN WELD COUNTY GIVEN STRONGER SUBSIDENCE INVERSION TOWARD
THE SOUTHEAST. LATEST RAP AND HRRR RUNS ALSO SUPPORT THIS.
&&
.AVIATION...CURRENT FORECAST LOOKS GOOD. MOST THUNDERSTORMS WILL
REMAIN CONFINED TO LOCATIONS IN/NEAR THE FOOTHILLS WITH NORTHWEST
APPROACH GATE HAVING THUNDERSTORMS 18Z-03Z...AND SCATTERED STORMS
AT SOUTHWEST APPROACH GATE. AT THE AIRPORTS...KBJC WOULD SEE A
LITTLE BETTER CHANCE OF -TSRA AND GUSTY OUTFLOW WINDS TO AROUND
30-35 KTS...WHILE LOWER CHANCE FARTHER AWAY FROM THE FOOTHILLS AT
KDEN AND KAPA.
&&
.HYDROLOGY...LOCALLY HEAVY RAIN STILL POSSIBLE FROM STRONGER
STORMS THIS AFTERNOON AND EVENING DUE TO A LITTLE HIGHER CAPE.
STRONGEST STORMS WOULD BE CAPABLE OF PRODUCING 0.50 TO 1.0 INCH
IN 20-30 MINUTES...AND THUS SOME MINOR FLOODING THREAT IN
FOOTHILL BURN SCARS.
&&
.PREV DISCUSSION... /ISSUED 328 AM MDT TUE AUG 27 2013/
SHORT TERM...ANOTHER REPEAT OF THE PAST FEW DAYS IS EXPECTED AS
AN UPPER LEVEL HIGH CONTINUES TO RESIDE OVER THE MIDDLE OF THE
COUNTRY. AIRMASS DRIES A LITTLE WITH PRECIPITABLE WATER VALUES
TOPPING OUT AROUND AN INCH. INSTABILITY WILL INCREASE TO WITH
VALUES UP TO 1000 J/KG OVER THE HIGHER TERRAIN AND FRONT RANGE.
EVEN THOUGH THE AIRMASS DRIES A LITTLE...STORMS MAY BE ABLE TO
PRODUCE MORE HEAVY AND PERHAPS SMALL HAIL BECAUSE OF THE BETTER
INSTABILITY LEADING TO STRONGER UPDRAFTS.
SCATTERED STORMS WILL DEVELOP OVER THE HIGHER TERRAIN ONCE AGAIN
THIS AFTERNOON. SCATTERED TO ISOLATED STORMS ARE EXPECTED ALONG THE
FRONT RANGE LATE THIS AFTERNOON AND EARLY EVENING. WARM AIR ALOFT
WILL CAP CONVECTION OVER THE EASTERN PLAINS AGAIN.
DRIER MOVING INTO THE AREA WILL LEAD TO MOSTLY CLEAR SKIES AFTER
MIDNIGHT. LOWS WILL REMAIN ABOVE NORMAL DUE TO THE WARM AIRMASS WITH
LOWS IN THE UPPER 50S TO MID 60S.
LONG TERM...AT 12Z WEDNESDAY...MODELS SHOW THE CENTER OF AN UPPER
RIDGE OVER WEST CENTRAL MISSOURI. IT MOVES LITTLE THROUGH
THURSDAY...THEN THE CENTER REDEVELOPS OVER COLORADO THURSDAY
NIGHT. THE MODELS CONTINUE TO SHOW A WEAK UPPER LOW CIRCULATION
WITHIN THE RIDGE...WEDNESDAY THROUGH THURSDAY. IT IS MAINLY
LOCATED OVER WESTERN KANSAS. THE FLOW ALOFT FOR THE CWA IS WEAK
AND NORTH OR NORTHEASTERLY MUCH OF THE FOUR PERIODS DUE THE WEAK
UPPER LOW. THERE IS NO SYNOPTIC SCALE ENERGY TO SPEAK OF ALL FOUR
PERIODS. FOR MOISTURE...IT DEFINITELY DRIES OUT SOMEWHAT WEDNESDAY
AND THURSDAY. PRECIPITABLE WATER VALUES ARE IN THE 0.60 TO 0.80
INCH RANGE OVER THE PLAINS WEDNESDAY THROUGH THURSDAY NIGHT. THE
BOUNDARY LAYER DEW POINTS ARE PROGGED TO STAY IN THE 40S F OVER
MUCH OF THE CWA ALL FOUR PERIODS. THERE IS SOME CAPE AROUND LATE
DAY WEDNESDAY...MOSTLY IN THE MOUNTAINS AND FOOTHILLS...WITH
NEARLY NONE OVER THE PLAINS. THURSDAY IS SIMILAR. THE LAPSE RATE
FIELDS SHOW A FAIRLY DECENT MID LEVEL CAP IN PLACE OVER THE PLAINS
FOR SURE LATE DAY WEDNESDAY AND LATE DAY THURSDAY. IT IS MORE
PRONOUNCED ON THE GFS. THE QPF FIELDS HAVE SOME MEASURABLE
RAINFALL OVER THE MOUNTAINS AND FOOTHILLS LATE DAY WEDNESDAY. JUST
A TAD LESS FOR LATE DAY THURSDAY. THERE IS NOTHING OVER THE PLAINS
BOTH DAYS. FOR POPS WILL STICK WITH 20-30%S IN THE MOUNTAINS AND
FOOTHILLS LATE DAY WEDNESDAY AND LATE DAY THURSDAY. FOR
TEMPERATURES...WEDNESDAY`S HIGHS LOOK PRETTY CLOSE TO TODAY`S
EXPECTED READINGS. THURSDAY HIGHS COME UP 0-1.5 C FROM
WEDNESDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY...THE
UPPER RIDGE IS CENTERED OVER COLORADO ALL FOUR DAYS. MOISTURE
INCREASES SOMEWHAT...ESPECIALLY ON SUNDAY AND MONDAY. TEMPERATURES
DO STAY ABOVE NORMAL.
AVIATION...SIMILAR CONDITIONS AS THE PAST FEW DAYS WILL PREVAIL
TODAY WITH ISOLATED THUNDERSTORMS POSSIBLE BETWEEN 22Z AND 03Z. THE
STORMS WILL BE SHORT LIVED WITH BRIEF HEAVY RAIN...SMALL HAIL AND
WIND GUSTS TO 40 KNOTS POSSIBLE WITH THE STORMS. OUTSIDE OF
THUNDERSTORMS...LIGHT WINDS WILL PREVAIL TODAY.
HYDROLOGY...MOISTURE DECREASES A LITTLE TODAY...BUT THE INSTABILITY
WILL INCREASE. THE STORMS THAT DO FORM MAY HAVE A BETTER CHANCE OF
PRODUCING HEAVY. STORMS ARE EXPECT TO BE SHORT LIVED WITH UP TO ONE
INCH OF RAIN POSSIBLE WITH THE STRONGEST STORMS IN 20 MINUTES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....RJK
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
909 AM CDT TUE AUG 27 2013
.DISCUSSION...
324 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE TODAY`S HEAT...THEN
TEMPS/POPS AS WE TEETER ON THE PERIPHERY OF UNSEASONABLY STRONG LATE
SUMMER UPPER HOT DOME INTO THE WEEKEND.
THE CARCASS OF SUNDAY NIGHT`S MCS PROVIDED A SHROUD OF FAIRLY DENSE
CIRRUS OVER THE AREA MONDAY AFTERNOON HOLDING TEMPS ABOUT 2-4F
COOLER THAN EXPECTED. ONCE AGAIN EARLY THIS MORNING MCS ACTIVITY IS
FESTERING ABOUT TO OUR NORTH ON THE PERIPHERY OF THE UPPER RIDGE.
CONVECTIVELY ENHANCED VORT DRIVING THIS MCS APPEARS TO BE PUSHING
INTO NORTHERN PORTIONS OF LAKE MICHIGAN ALREADY WITH BACK EDGE OF
CIRRUS SHIELD MOVING INTO NW WISCONSIN. HRRR SEEMS TO HAVE A GOOD
HANDLE ON ONGOING CONVECTIVE TRENDS AND IT...ALONG WITH THE MAJORITY
OF THE OTHER GUIDANCE...SUGGESTS THAT TODAY`S CIRRUS DEBRIS WILL
CLEAR OUT BY EARLY AFTERNOON AND ALLOW FOR STRONG HEATING TO TAKE
PLACE...ESPECIALLY NORTHWESTERN CWA. LOW LEVEL THERMAL RIDGE
MOVING INTO THE AREA WITH 925MB TEMPS PROGGED TO RISE TO 26-28C
NORTHWESTERN CWA WHICH WOULD EASILY SUPPORT MIDDLE IF NOT UPPER
90S. IN THE PAST HOUR CONVECTION HAS FLARED OVER NORTHEAST MINNESOTA
WHICH IS CONCERNING AS 850-300MB THICKNESS SUGGESTS THAT COULD SINK
SOUTHWARD AND SPREAD MORE CIRRUS ACROSS THE AREA TODAY.
GIVEN POTENTIAL FOR DEBRIS CLOUDINESS TO LINGER AGAIN TODAY SPLIT
THE DIFFERENCE FOR HIGHS BETWEEN WHAT PROGGED 925MB TEMPS WOULD
SUPPORT AND WHAT CLIMO INFLUENCED MOS NUMBERS FORECAST. ASSUMING
DEWPOINTS DON`T MIX OUT AND ASSUMING CIRRUS CLEARS OUT THEN WE WOULD
GET CLOSE TO THE 105F HEAT INDEX ADVISORY CRITERIA THIS AFTERNOON
NORTH/NORTHWEST AREAS. GIVEN A FORECAST OF CONDITIONS NOT MEETING
CRITERIA AND LOW CONFIDENCE IN THEM EVEN GETTING AS BAD AS I HAVE IN
THE GRIDS...WOULD NOT NORMALLY ISSUE AN ADVISORY...BUT WITH
HEADLINES OUT FOR AREAS NORTH/WEST OF OUR CWA AND POTENTIAL FOR NEAR
RECORD HIGHS DECIDED TO MAKE THE W/W/A MAP PRETTY AND HOIST AN
ADVISORY FOR NORTH CENTRAL ILLINOIS. IF TRENDS THIS MORNING SUGGEST
THAT CIRRUS WONT BE A BIG DEAL THEN DAY SHIFT COULD CONSIDER
EXTENDING THE ADVISORY FARTHER EAST INTO THE CHICAGO AREA.
ANOTHER SHORTWAVE OVER THE EASTERN DAKOTAS THIS MORNING IS PROGGED
TO RIDE THE RIM OF THE RIDGE EAST INTO WISCONSIN THIS AFTERNOON AND
WILL PROBABLY RE-IGNITE THUNDERSTORMS TO OUR NORTH THIS AFTERNOON
WITH THESE STORMS POTENTIALLY CLIPPING OUR NORTHERN AND NORTHEASTERN
CWA THIS EVENING AS THE MOVE SOUTHEASTWARD. MODERATELY STRONG MID
LEVEL FLOW AND FAIRLY STRONG INSTABILITY (ASSUMING TDS DONT MIX OUT)
COULD SUPPORT A LOW END SEVERE THREAT WITH ANY STORMS THAT DO
MEANDER INTO OUR CWA TONIGHT.
LAKE ENHANCED COLD FRONT WILL MOVE INTO THE CWA EARLY WEDNESDAY
MORNING PROGRESSING SOUTHWARD INTO OUR SOUTHERN CWA BY AFTERNOON.
BETTER FORCING ALOFT SHOULD REMAIN TO OUR EAST BUT AM CONCERNED THAT
MOISTURE/INSTABILITY POOLING AND LOW LEVEL CONVERGENCE ALONG THE
FRONT COULD BE ENOUGH TO KICK OFF A THUNDERSTORM WEDNESDAY
AFTERNOON. SLIGHTLY COOLER AIR MASS WILL FILTER IN BEHIND THE
FRONT...WITH COOLING MOST NOTICEABLE NEAR LAKE MICHIGAN. AHEAD OF THE
FRONT WILL BE ANOTHER STEAMY DAY AND WITH BETTER DEWPOINT POOLING
COULD ACTUALLY END UP BEING HOTTER/MORE HUMID IN OUR SOUTHERN CWA
TOMORROW THAN TODAY...BUT THAT WILL HINGE ON THE AMOUNT OF
CLOUDINESS SOMETHING WHICH WILL BE MORE EASILY DIAGNOSED TONIGHT.
LOW LEVEL BAROCLINIC ZONE HANGS UP IN THE NEIGHBORHOOD THROUGH THE
END OF THE WEEK WITH WEAK NORTHWEST FLOW IMPULSES LIKELY TO RIPPLE
AROUND THE PERIPHERY OF THE HEAT DOME MEANS AT LEAST SOME POTENTIAL
FOR THUNDERSTORMS TONIGHT UNTIL STRONG COLD FRONT MOVES THROUGH THIS
WEEKEND. HAVE KEPT FORECAST DRY FOR NOW WEDNESDAY NIGHT THROUGH
THURSDAY BUT NW FLOW`S LIKE THIS ARE NOTORIOUS FOR PRODUCING
"SURPRISES" SO STAY TUNED!
HEADING INTO THE SECOND HALF OF THE LABOR DAY WEEKEND THE DIFFERENCE
BETWEEN THE 27/00Z RUN OF THE ECMWF WHEN COMPARED TO THE 25/12Z RUN
IS ABOUT AS DRAMATIC I`VE EVER SEEN IN THE WARM SEASON. FOR DAYS
MEDIUM RANGE MODELS HAD BEEN ADVERTISING RECORD BREAKING HEAT AND
NOW AFTER STARTING TO TREND SHARPLY COLDER WITH THE 26/12Z RUN THE
LATEST ECMWF NOW FORECASTS NEAR RECORD COLD TEMPERATURES BY MONDAY
WITH H8 TEMPS NEARING 0C! THE REMAINDER OF THE MEDIUM RANGE MODELS
HAVE BEEN TRENDING TOWARD THIS EARLIER FROPA/STRONG COLD PUSH
SOLUTION BUT STILL LAG WELL BEHIND THE UNSEASONABLY COLD ECMWF. IF
ECMWF WERE TO VERIFY WITH THIS INTENSE COOL SNAP THEN OUR FORECAST
WILL LIKELY TAKE A COUPLE MORE CYCLES TO CATCH UP WITH SUCH AN
ABRUPT CHANGE BUT HAVE TRENDED TEMPS DOWN SIGNIFICANTLY FROM THE
INITIALIZED ALLBLEND GUIDANCE...THOUGH IF LATEST EC VERIFIES HIGHS
MONDAY WOULD LIKELY BE IN THE 60S! NEEDLESS TO SAY FORECAST
CONFIDENCE IN THIS TIME PERIOD WILL REMAIN LOW UNTIL WE BEGIN TO SEE
MODELS CONVERGE ON A SOLUTION AND REMAIN MORE STABLE FROM RUN TO RUN.
IZZI
&&
.CLIMATE...
HERE ARE THE RECORD HIGHS FOR TUESDAY...
CHICAGO ROCKFORD
TUESDAY 97 (1973) 97 (1953)
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NO CONCERNS IN THE NEAR TERM.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS OVER THE SOUTHEAST US WHILE LOW PRESSURE IS OVER
EASTERN SD/SOUTHERN MN. THE LOW PRESSURE WILL TRACK ACROSS MN AND
WI TODAY BEFORE DRIFTING OVER LAKE MICHIGAN AND MI THIS EVENING/TONIGHT.
HIGH LEVEL CLOUD COVER FROM A DYING COMPLEX OVER MI HAS SPREAD
ACROSS THE REGION AND WE MAY GET ANOTHER ROUND OF HIGH LEVEL
CLOUDS FROM A SECOND CONVECTIVE SYSTEM OVER NORTHERN WI.
SW WIND GUSTS WILL ONCE AGAIN INCREASE BY MID MORNING WITH
SLIGHTLY STRONGER SUSTAINED SPEEDS THAN YESTERDAY...ARND 12KT.
GUSTS WILL BE ARND 18KT WITH OCNL GUSTS ARND 20KT ESPECIALLY LATE
THIS AFTN. GUSTS DIMINISH THIS EVENING AS THE LOWS COLD FRONT
APPROACHES FROM THE NORTH. THINKING WINDS WILL BEGIN TO VEER TO
THE NW LATE TONIGHT BECOMING N TO NNE TOMORROW MORNING.
FOR PRECIP...GUIDANCE CONTINUES TO INDICATE ISOL-SCT SHRA/TSRA
WILL DEVELOP TO THE NORTH AND EAST OF THE TERMINALS THIS EVENING
AND OVERNIGHT. THEREFORE KEPT THE TAFS DRY. IF STORMS WERE TO
REACH ANY OF THE TERMINALS...IT NOW LOOKS LIKE GYY WOULD BE THE
BEST BET.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA TRENDS AROUND THE TERMINALS
TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR PSBL.
THURSDAY...SCHC SHRA/TSRA OVERNIGHT
FRIDAY AND SATURDAY...CHC SHRA/TSRA.
SUNDAY AND MONDAY...VFR.
JEE
&&
.MARINE...
225 AM CDT
LOW PRESSURE OVER SOUTH DAKOTA THIS MORNING WILL PASS OVER THE LAKE
TODAY WITH ITS COLD FRONT SLIDING DOWN THE LAKE TONIGHT. AS SUCH
GUSTY SW WINDS ARE ONCE AGAIN EXPECTED OVER THE SOUTHERN HALF OF THE
LAKE TODAY WITH LIGHTER EAST WINDS OVER THE NORTHERN HALF. WINDS
TURN NW TO N BEHIND THE FRONT TONIGHT THEN AS THE HIGH SETTLES IN
OVER THE REGION...WINDS BECOME LIGHT AND VARIABLE. THE HIGH SHIFTS
EAST THURSDAY NIGHT WITH WINDS BECOMING SOUTH ON FRIDAY. LIGHT
WINDS ARE EXPECTED THROUGH THE END OF THIS WEEK...BUT A STRONG LOW
FORMS OVER SASKATCHEWAN FRIDAY NIGHT. GUIDANCE SUGGESTS THE LOW
WILL PASS NORTH OF LAKE MICHIGAN BUT STRONG NW WINDS ARND 30 KT ARE
EXPECTED BEHIND THE LOWS COLD FRONT SUNDAY NIGHT INTO MONDAY
ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011 UNTIL 8 PM
TUESDAY.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
703 AM CDT TUE AUG 27 2013
.DISCUSSION...
324 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE TODAY`S HEAT...THEN
TEMPS/POPS AS WE TEETER ON THE PERIPHERY OF UNSEASONABLY STRONG LATE
SUMMER UPPER HOT DOME INTO THE WEEKEND.
THE CARCASS OF SUNDAY NIGHT`S MCS PROVIDED A SHROUD OF FAIRLY DENSE
CIRRUS OVER THE AREA MONDAY AFTERNOON HOLDING TEMPS ABOUT 2-4F
COOLER THAN EXPECTED. ONCE AGAIN EARLY THIS MORNING MCS ACTIVITY IS
FESTERING ABOUT TO OUR NORTH ON THE PERIPHERY OF THE UPPER RIDGE.
CONVECTIVELY ENHANCED VORT DRIVING THIS MCS APPEARS TO BE PUSHING
INTO NORTHERN PORTIONS OF LAKE MICHIGAN ALREADY WITH BACK EDGE OF
CIRRUS SHIELD MOVING INTO NW WISCONSIN. HRRR SEEMS TO HAVE A GOOD
HANDLE ON ONGOING CONVECTIVE TRENDS AND IT...ALONG WITH THE MAJORITY
OF THE OTHER GUIDANCE...SUGGESTS THAT TODAY`S CIRRUS DEBRIS WILL
CLEAR OUT BY EARLY AFTERNOON AND ALLOW FOR STRONG HEATING TO TAKE
PLACE...ESPECIALLY NORTHWESTERN CWA. LOW LEVEL THERMAL RIDGE
MOVING INTO THE AREA WITH 925MB TEMPS PROGGED TO RISE TO 26-28C
NORTHWESTERN CWA WHICH WOULD EASILY SUPPORT MIDDLE IF NOT UPPER
90S. IN THE PAST HOUR CONVECTION HAS FLARED OVER NORTHEAST MINNESOTA
WHICH IS CONCERNING AS 850-300MB THICKNESS SUGGESTS THAT COULD SINK
SOUTHWARD AND SPREAD MORE CIRRUS ACROSS THE AREA TODAY.
GIVEN POTENTIAL FOR DEBRIS CLOUDINESS TO LINGER AGAIN TODAY SPLIT
THE DIFFERENCE FOR HIGHS BETWEEN WHAT PROGGED 925MB TEMPS WOULD
SUPPORT AND WHAT CLIMO INFLUENCED MOS NUMBERS FORECAST. ASSUMING
DEWPOINTS DON`T MIX OUT AND ASSUMING CIRRUS CLEARS OUT THEN WE WOULD
GET CLOSE TO THE 105F HEAT INDEX ADVISORY CRITERIA THIS AFTERNOON
NORTH/NORTHWEST AREAS. GIVEN A FORECAST OF CONDITIONS NOT MEETING
CRITERIA AND LOW CONFIDENCE IN THEM EVEN GETTING AS BAD AS I HAVE IN
THE GRIDS...WOULD NOT NORMALLY ISSUE AN ADVISORY...BUT WITH
HEADLINES OUT FOR AREAS NORTH/WEST OF OUR CWA AND POTENTIAL FOR NEAR
RECORD HIGHS DECIDED TO MAKE THE W/W/A MAP PRETTY AND HOIST AN
ADVISORY FOR NORTH CENTRAL ILLINOIS. IF TRENDS THIS MORNING SUGGEST
THAT CIRRUS WONT BE A BIG DEAL THEN DAY SHIFT COULD CONSIDER
EXTENDING THE ADVISORY FARTHER EAST INTO THE CHICAGO AREA.
ANOTHER SHORTWAVE OVER THE EASTERN DAKOTAS THIS MORNING IS PROGGED
TO RIDE THE RIM OF THE RIDGE EAST INTO WISCONSIN THIS AFTERNOON AND
WILL PROBABLY RE-IGNITE THUNDERSTORMS TO OUR NORTH THIS AFTERNOON
WITH THESE STORMS POTENTIALLY CLIPPING OUR NORTHERN AND NORTHEASTERN
CWA THIS EVENING AS THE MOVE SOUTHEASTWARD. MODERATELY STRONG MID
LEVEL FLOW AND FAIRLY STRONG INSTABILITY (ASSUMING TDS DONT MIX OUT)
COULD SUPPORT A LOW END SEVERE THREAT WITH ANY STORMS THAT DO
MEANDER INTO OUR CWA TONIGHT.
LAKE ENHANCED COLD FRONT WILL MOVE INTO THE CWA EARLY WEDNESDAY
MORNING PROGRESSING SOUTHWARD INTO OUR SOUTHERN CWA BY AFTERNOON.
BETTER FORCING ALOFT SHOULD REMAIN TO OUR EAST BUT AM CONCERNED THAT
MOISTURE/INSTABILITY POOLING AND LOW LEVEL CONVERGENCE ALONG THE
FRONT COULD BE ENOUGH TO KICK OFF A THUNDERSTORM WEDNESDAY
AFTERNOON. SLIGHTLY COOLER AIR MASS WILL FILTER IN BEHIND THE
FRONT...WITH COOLING MOST NOTICEABLE NEAR LAKE MICHIGAN. AHEAD OF THE
FRONT WILL BE ANOTHER STEAMY DAY AND WITH BETTER DEWPOINT POOLING
COULD ACTUALLY END UP BEING HOTTER/MORE HUMID IN OUR SOUTHERN CWA
TOMORROW THAN TODAY...BUT THAT WILL HINGE ON THE AMOUNT OF
CLOUDINESS SOMETHING WHICH WILL BE MORE EASILY DIAGNOSED TONIGHT.
LOW LEVEL BAROCLINIC ZONE HANGS UP IN THE NEIGHBORHOOD THROUGH THE
END OF THE WEEK WITH WEAK NORTHWEST FLOW IMPULSES LIKELY TO RIPPLE
AROUND THE PERIPHERY OF THE HEAT DOME MEANS AT LEAST SOME POTENTIAL
FOR THUNDERSTORMS TONIGHT UNTIL STRONG COLD FRONT MOVES THROUGH THIS
WEEKEND. HAVE KEPT FORECAST DRY FOR NOW WEDNESDAY NIGHT THROUGH
THURSDAY BUT NW FLOW`S LIKE THIS ARE NOTORIOUS FOR PRODUCING
"SURPRISES" SO STAY TUNED!
HEADING INTO THE SECOND HALF OF THE LABOR DAY WEEKEND THE DIFFERENCE
BETWEEN THE 27/00Z RUN OF THE ECMWF WHEN COMPARED TO THE 25/12Z RUN
IS ABOUT AS DRAMATIC I`VE EVER SEEN IN THE WARM SEASON. FOR DAYS
MEDIUM RANGE MODELS HAD BEEN ADVERTISING RECORD BREAKING HEAT AND
NOW AFTER STARTING TO TREND SHARPLY COLDER WITH THE 26/12Z RUN THE
LATEST ECMWF NOW FORECASTS NEAR RECORD COLD TEMPERATURES BY MONDAY
WITH H8 TEMPS NEARING 0C! THE REMAINDER OF THE MEDIUM RANGE MODELS
HAVE BEEN TRENDING TOWARD THIS EARLIER FROPA/STRONG COLD PUSH
SOLUTION BUT STILL LAG WELL BEHIND THE UNSEASONABLY COLD ECMWF. IF
ECMWF WERE TO VERIFY WITH THIS INTENSE COOL SNAP THEN OUR FORECAST
WILL LIKELY TAKE A COUPLE MORE CYCLES TO CATCH UP WITH SUCH AN
ABRUPT CHANGE BUT HAVE TRENDED TEMPS DOWN SIGNIFICANTLY FROM THE
INITIALIZED ALLBLEND GUIDANCE...THOUGH IF LATEST EC VERIFIES HIGHS
MONDAY WOULD LIKELY BE IN THE 60S! NEEDLESS TO SAY FORECAST
CONFIDENCE IN THIS TIME PERIOD WILL REMAIN LOW UNTIL WE BEGIN TO SEE
MODELS CONVERGE ON A SOLUTION AND REMAIN MORE STABLE FROM RUN TO RUN.
IZZI
&&
.CLIMATE...
HERE ARE THE RECORD HIGHS FOR TUESDAY...
CHICAGO ROCKFORD
TUESDAY 97 (1973) 97 (1953)
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* WINDS BECOMING N TO NNE ARND 8KT WEDNESDAY MORNING.
JEE
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS OVER THE SOUTHEAST US WHILE LOW PRESSURE IS OVER
EASTERN SD/SOUTHERN MN. THE LOW PRESSURE WILL TRACK ACROSS MN AND
WI TODAY BEFORE DRIFTING OVER LAKE MICHIGAN AND MI THIS EVENING/TONIGHT.
HIGH LEVEL CLOUD COVER FROM A DYING COMPLEX OVER MI HAS SPREAD
ACROSS THE REGION AND WE MAY GET ANOTHER ROUND OF HIGH LEVEL
CLOUDS FROM A SECOND CONVECTIVE SYSTEM OVER NORTHERN WI.
SW WIND GUSTS WILL ONCE AGAIN INCREASE BY MID MORNING WITH
SLIGHTLY STRONGER SUSTAINED SPEEDS THAN YESTERDAY...ARND 12KT.
GUSTS WILL BE ARND 18KT WITH OCNL GUSTS ARND 20KT ESPECIALLY LATE
THIS AFTN. GUSTS DIMINISH THIS EVENING AS THE LOWS COLD FRONT
APPROACHES FROM THE NORTH. THINKING WINDS WILL BEGIN TO VEER TO
THE NW LATE TONIGHT BECOMING N TO NNE TOMORROW MORNING.
FOR PRECIP...GUIDANCE CONTINUES TO INDICATE ISOL-SCT SHRA/TSRA
WILL DEVELOP TO THE NORTH AND EAST OF THE TERMINALS THIS EVENING
AND OVERNIGHT. THEREFORE KEPT THE TAFS DRY. IF STORMS WERE TO
REACH ANY OF THE TERMINALS...IT NOW LOOKS LIKE GYY WOULD BE THE
BEST BET.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN SCT SHRA/TSRA THIS EVENING BTWN 00 AND
06Z...BUT MEDIUM-HIGH CONFIDENCE IN SHRA/TSRA REMAINING OUTSIDE
OF TERMINALS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR PSBL.
THURSDAY...SCHC SHRA/TSRA OVERNIGHT
FRIDAY AND SATURDAY...CHC SHRA/TSRA.
SUNDAY AND MONDAY...VFR.
JEE
&&
.MARINE...
225 AM CDT
LOW PRESSURE OVER SOUTH DAKOTA THIS MORNING WILL PASS OVER THE LAKE
TODAY WITH ITS COLD FRONT SLIDING DOWN THE LAKE TONIGHT. AS SUCH
GUSTY SW WINDS ARE ONCE AGAIN EXPECTED OVER THE SOUTHERN HALF OF THE
LAKE TODAY WITH LIGHTER EAST WINDS OVER THE NORTHERN HALF. WINDS
TURN NW TO N BEHIND THE FRONT TONIGHT THEN AS THE HIGH SETTLES IN
OVER THE REGION...WINDS BECOME LIGHT AND VARIABLE. THE HIGH SHIFTS
EAST THURSDAY NIGHT WITH WINDS BECOMING SOUTH ON FRIDAY. LIGHT
WINDS ARE EXPECTED THROUGH THE END OF THIS WEEK...BUT A STRONG LOW
FORMS OVER SASKATCHEWAN FRIDAY NIGHT. GUIDANCE SUGGESTS THE LOW
WILL PASS NORTH OF LAKE MICHIGAN BUT STRONG NW WINDS ARND 30 KT ARE
EXPECTED BEHIND THE LOWS COLD FRONT SUNDAY NIGHT INTO MONDAY
ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011...NOON
TUESDAY TO 8 PM TUESDAY.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1140 AM EDT TUE AUG 27 2013
.SYNOPSIS...
ISSUED AT 1140 AM EDT TUE AUG 27 2013
A FRONTAL BOUNDARY WILL IMPACT THE REGION OVER THE NEXT 24 TO 36
HOURS. ALONG AND NORTH OF IT...CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL EXIST INTO TONIGHT...ESPECIALLY ACROSS MUCH OF
LOWER MICHIGAN INTO PARTS OF NORTHERN INDIANA AND NORTHWESTERN
OHIO. SOUTH OF THE FRONT...HOT AND HUMID CONDITIONS WILL PREVAIL
WITH LITTLE CHANCE OF RAIN.
&&
.UPDATE...
ISSUED AT 1140 AM EDT TUE AUG 27 2013
NO SIG CHANGES TO FORECAST PLANNED AT THIS TIME.
FOCUS OF FORECAST INTO THIS AFTERNOON WILL BE ON 2ND COMPLEX OF
SHOWERS/STORMS MOVING INTO LWR MI AND SEVERAL OUTFLOW BOUNDARIES
ACROSS THE REGION.
AREA OF SHOWERS AND A FEW STORMS MOVING INTO NW LWR MICHIGAN WAS
SHOWING SIGNS OF WEAKENING PER LATEST RADAR TRENDS AND WARMING
CLOUD TOPS. THIS SHOULD CONTINUE TO TRACK SE AND REMAIN GENERALLY
NE OF THE AREA FOLLWOWING THE EDGE OF THE THETA E RIDGE FROM
MUSKEGON TOWARDS ANN ARBOR. HRRR HAS BEEN SPORADICALLY INDICATING
SOME ADDITIONAL DEVELOPMENT ON THE SW FLANK OF THIS AREA THAT
WOULD CLIP NE AREAS BUT LATEST RUNS HAVE BACKED OFF. MAIN FOCUS
MAY END UP BEING ASSOCIATED OUTFLOW DROPPING SE ACROSS
CENTRAL/SOUTHERN WISCONSIN. THIS WILL ARRIVE IN THE AREA THIS
AFTERNOON AS PEAK HEATING IS UNDERWAY. AT THIS POINT..CAN`T
JUSTIFY ANY POPS CHANGES IN EITHER DIRECTION AS MUCH LIKE
YESTERDAY THERE APPEAR TO BE NO OVERALL EFFECT ON SFC FLOW OR LIFT
PER OBSERVATIONS INDICATING NO CONVERGENCE OR EVEN CLOUD COVER
ASSOCIATED WITH IT.
IN TERMS OF TEMPS...SLIGHT LOWERING OF TEMPS MAY BE NEEDED NE BUT
WITH SKIES TRYING TO CLEAR OUT AND MAIN PUSH OF NEXT ROUND OF
CONVECTION LIKELY STAYING FURTHER NORTH...MAY BE ABLE TO SQUEEZE
UP MID/UPR 80S YET.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EDT TUE AUG 27 2013
CHALLENGES TODAY AND TONIGHT CENTER AROUND DEVELOPMENT...TIMING...
LOCATION AND SEVERITY OF THUNDERSTORMS. THUNDERSTORMS HAVE BEEN
FORMING AND TRACKING OVERNIGHT ALONG A LOW LEVEL THETA E RIDGE WHERE
THETA E CONVERGENCE HAS BEEN OCCURRING. AN EMBEDDED SHORT WAVE WILL
TOP THE RIDGE EARLY TODAY AND WILL DESCENT SOUTHEAST ACROSS THE
WESTERN GREAT LAKES REGION. A NUMBER OF FACTOR SHOULD COME TOGETHER
FOR THUNDERSTORMS AS LOW LEVEL THETA E INCREASES AHEAD OF A WEAK
FRONT. ALTHOUGH MID LEVEL LAPSE RATES GENERALLY UNFAVORABLE FOR
CONVECTION...SOME SUPPORT FROM AN EXIT REGION OF AN UPPER LEVEL
JET...LOW LEVEL CONVERGENCE...AND FAVORABLE LOW LEVEL INSTABILITY
SHOULD AID IN STORM DEVELOPMENT. STRONG TO POSSIBLY SEVERE STORMS
SHOULD OCCUR ESPECIALLY OVER FAR NORTH AND NORTHEAST AREAS INCLUDE
COLDWATER AND HILLSDALE. OTHERWISE...KEPT TEMPERATURES HOT
TODAY...BACKED OFF A LITTLE WITH HIGHS OVER FAR NORTHEAST AREAS
WHERE CLOUDS AND STORMS MAY KEEP TEMPERATURES FROM REACHING 90
DEGREES.
&&
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 441 AM EDT TUE AUG 27 2013
A SHEARED VORTICITY MAXIMUM WILL CONTINUE TO TOP PERSISTENT LONGWAVE
UPPER RIDGE ACROSS CENTRAL CONUS INTO WEDNESDAY MORNING...ALLOWING
FOR SLIGHT DAMPENING OF MID LEVEL HEIGHTS ACROSS THE SOUTHERN GREAT
LAKES. MAINTENANCE OF UPPER LEVEL RIDGE AXIS POSITION...AND EVEN
SLIGHT RETROGRESSION INTO WEDNESDAY MORNING WILL ALLOW FOR A MORE
FAVORABLE MCS TRACK INTO ESPECIALLY NORTHEAST PORTIONS OF THE AREA.
AXIS OF MORE ENHANCED LOW LEVEL MOISTURE POOLING (PWATS AROUND 2
INCHES) WILL ALSO BE DRAWN SOUTHWARD WITH THE COOL FRONT EARLY
WEDNESDAY ENHANCING EARLY MORNING PRECIP CHANCES.
DRYING TREND EXPECTED BY MID MORNING WEDNESDAY WITH LOW CONFIDENCE
ON MESOSCALE DETAILS FOR REMAINDER OF THE DAY GIVEN IMPACTS FROM
MORNING CLOUDS AND POTENTIAL PRECIP. STRONGER MID LEVEL SHORT WAVE
WILL LIKELY DROP SOUTHEAST INTO THE LOWER OHIO VALLEY DURING THE
AFTERNOON WITH ANY ADDITIONAL UPSTREAM MID LEVEL FORCING HARD TO
LATCH ONTO AT THIS FORECAST DISTANCE AND LIKELY WEAK IN NATURE.
PERSISTENCE OF MID/UPPER RIDGE WILL ALSO KEEP SOME RATHER WEAK MID
LEVEL LAPSE RATES IN PLACE ACROSS THE REGION. PRESENCE OF POOLED
FRONTAL MOISTURE SHOULD ALLOW FOR WEAK TO NO SBCIN IN THE
AFTERNOON...BUT RESIDUAL CONVECTIVE DEBRIS AND LOW LEVEL TEMPERATURE
TRENDS WILL BE IMPORTANT IN RESOLVING EXACT MAGNITUDE OF
INSTABILITY/CIN. A POCKET OF AT LEAST MODERATE AFTERNOON SURFACE
BASED INSTABILITY MAY DEVELOP ACROSS SOUTHERN HALF OF THE AREA IN
THE AFTERNOON...AND GIVEN ALL ABOVE FACTORS SLIGHT CHANCE TO LOW
CHANCE TSRA POPS STILL SEEM TO BE IN ORDER. SEVERE THREAT WILL BE
LIMITED BY WEAK MID LEVEL LAPSE RATES AND MARGINAL SHEAR
PROFILES...WITH MODELS GENERALLY INDICATING BELT OF SLIGHTLY
STRONGER MID/UPPER FLOW SHIFTING SOUTHEAST OF THE AREA IN THE
AFTERNOON. THE OTHER CONCERN FOR WEDNESDAY WILL BE ON TEMPERATURES
PARTICULARLY ACROSS THE SOUTH IN ADVANCE OF THE FRONT. POOLED LOWER
70S DEW POINTS APPEAR TO BE A GOOD POSSIBILITY...AND WITH FORECASTED
HIGHS IN THE LOWER 90S...PEAK AFTERNOON HEAT INDICES COULD REACH
INTO THE MID 90S...AND INTO THE UPPER 90S FAR SOUTH IF SOME
INSOLATION CAN BE REALIZED.
COOLER AND LESS HUMID CONDITIONS FOR THURSDAY...ALTHOUGH
TEMPERATURES STILL EXPECTED ABOVE NORMAL GIVEN SHALLOW AND WEAK
NATURE OF COOL FRONT. MODELS CONTINUE TO SUGGEST UPPER RIDGE AXIS TO
RETROGRADE SLIGHTLY WESTWARD WITH RENEWED WARM ADVECTION/THETA
ADVECTION FORCING WORKING IN FROM THE WEST FOR THE FRIDAY/SATURDAY
PERIOD. MUCH TOO EARLY TO RESOLVE TIMING OF FAST MOVING SHORT WAVES
RIDING DOWN THE RIDGE...BUT 20-30 POPS MAINTAINED THROUGH THIS
PERIOD GIVEN LARGE SCALE PATTERN SUPPORT.
FORECAST CONFIDENCE QUITE LOW FOR SUNDAY AND BEYOND WITH MEDIUM
RANGE MODELS SHOWING SOME RUN TO RUN VOLATILITY AS OF LATE.
INTERESTINGLY...00Z GFS HAS MADE A SHARP TURN TOWARD THE IDEA OF
PAST FEW RUNS OF THE ECMWF IN MORE AGGRESSIVELY DIGGING LARGE SCALE
UPPER TROUGH ACROSS SOUTHEAST CANADA/NORTHEAST CONUS FOR THE LATE
SUNDAY/MONDAY PERIOD...WITH A VERY COOL AIR MASS DROPPING INTO THE
GREAT LAKES REGION. EC REMAINS IN OUTLIER IN COMPARISON TO GFS/GEFS
WITH DEPTH OF THIS TROUGH BUT GIVEN AT LEAST A TREND TO CONVERGING
SOLUTIONS HAVE STEERED FORECAST TOWARD THIS COOLER IDEA MENTIONED IN
PREVIOUS DISCUSSION. SOME CHANCE OF PRECIP WOULD LIKELY ACCOMPANY
ASSOCIATED COLD FRONT...BUT WITH LARGE RUN TO RUN DIFFERENCES WILL
KEEP DAYS 6/7 DRY FOR THIS PACKAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 650 AM EDT TUE AUG 27 2013
ACTIVE PATTERN OF CONVECTION TO CONTINUE THIS PERIOD AROUND
NORTHERN PERIPHERY OF PERSISTENT CENTRAL CONUS UPPER RIDGE. ONE
MCS CONTINUES TO DECAY ACROSS LOWER MICHIGAN...AND ANY
PRECIPITATION THROUGH THE MORNING SHOULD REMAIN NORTH AND EAST OF
THE TERMINALS. THE NEXT UPPER LEVEL SHORT WAVE ROUNDING THE RIDGE
HAS AIDED IN THE INITIATION OF NEW CONVECTION ACROSS NORTHERN
WISCONSIN. CONVECTION WILL LIKELY EXPAND SOUTHEAST FROM NORTHERN
WISCONSIN THROUGH THE DAY...AND INTO NORTHERN INDIANA THIS
EVENING. BEST CHANCES OF THUNDERSTORMS APPEAR TO BE JUST EAST OF
TERMINALS...BUT SCATTERED COVERAGE IS A POSSIBILITY AT BOTH
TERMINALS FROM MID EVENING INTO THE OVERNIGHT AND HAVE INCLUDED
VCTS MENTION AT THIS FORECAST DISTANCE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...FISHER
SHORT TERM...SKIPPER
LONG TERM...MARSILI
AVIATION...MARSILI
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
622 AM CDT TUE AUG 27 2013
.SYNOPSIS...
ISSUED AT 357 AM CDT TUE AUG 27 2013
LARGE...NEARLY STATIONARY UPPER LEVEL HIGH CENTERED OVER EASTERN KS
AND MO AND DOME OF UNSEASONABLY WARM AIR ALOFT CONTINUES TO DOMINATE
THE SYNOPTIC WEATHER PICTURE. TONIGHT/S PRIMARY MCS...ROUNDING THE
TOP OF THE RIDGE WAS EVIDENT ON SATELLITE AND RADAR IMAGERY MOVING
INTO WESTERN LOWER MI...WHILE ADDITIONAL THUNDERSTORMS WERE
DEVELOPING FURTHER UPSTREAM NEAR DLH. AN ASSOCIATED SHIELD OF THIN
CI WAS COVERING MUCH OF EASTERN IA AND NORTHERN IL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED OVER EASTERN SD WITH A SURFACE
COLD FRONT/TROUGH REACHING EAST-NORTHEAST ACROSS CENTRAL MN AND
WI. SURFACE TEMPERATURES WERE IN THE LOWER TO MID 70S WITH
DEWPOINTS IN THE MID 60S TO AROUND 70 OVER THE FORECAST AREA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE AUG 27 2013
FOCUS IS ON POTENTIALLY RECORD BREAKING HEAT TODAY AS THERMAL RIDGE
ALOFT OVERHEAD WILL SUPPORT THE HOTTEST TEMPERATURES SO FAR OF
THE ON-GOING HEAT WAVE. DEEP MIXING AHEAD OF THE APPROACHING
FRONT IN THE NORTHERN PLAINS AND UPPER MS VALLEY WILL TAP INTO THE
THERMAL RIDGE OF 850 TEMPERATURES IN THE RANGE OF 22 TO 23 DEGREES
C. THIS SUPPORTS HIGHS IN THE MID TO UPPER 90S...AND CONTINUES A
TREND OF 1 TO 3 DEGREES DAY TO DAY WARMING TREND SINCE THE
WEEKEND. BASED ON VERIFICATION...WILL CONTINUE TO BUFFER MAXES
ALONG THE MORE MOIST HIGHWAY 20 CORRIDOR DOWN A DEGREE OR TWO. THE
KEY TO HOW HIGH THE HEAT INDEX GETS WILL BE HOW SURFACE DEWPOINTS
RESPOND TO STRONGER WINDS AND DEEP MIXING TODAY. FORECAST MODELS
ARE IN A COUPLE DIFFERENT CAMPS...WITH THE RAP SUGGESTING DRYING
OUT TO THE UPPER 50S TO LOWER 60 BY AFTERNOON...WHILE THE BULK OF
OTHER SHORT TERM MODELS ARE MUCH MORE MOIST WITH SOME SUGGESTING
POOLING OF LOWER TO MID 70S ACROSS THE NORTH. BASED ON
VERIFICATION FROM YESTERDAY HERE AND UPSTREAM IN THE
PLAINS...DEWPOINTS WILL MORE LIKELY RISE A FEW DEGREES EARLY THIS
MORNING...THEN SETTLE IN THE INTO THE MID TO UPPER 60S IN THE
AFTERNOON AS SW WINDS INCREASE TO 10 TO 15 MPH. UNLIKE
YESTERDAY...THE CLOUD SHIELD FROM THE NOCTURNAL CONVECTION SHOULD
BE OUT OF THE REGION BY MID MORNING...YIELDING NEAR FULL SUNSHINE
FOR THE AFTERNOON. HOWEVER...WILL NEED TO WATCH THE NW WI COMPLEX TRENDS
CLOSELY...AS THIS COULD POSSIBLY LEAD TO ANOTHER CI SHIELD IF IT
REMAINS STRONG...FOR LATER THIS MORNING.
HEAT INDEX READINGS THUS ARE EXPECTED TO REACH 100 TO 104 BY EARLY
AFTERNOON OVER MUCH OF THE FORECAST AREA...WITH A GENERAL GRADIENT
FROM LOWER VALUES EAST TO HIGHER WEST AND NW. THE ON-GOING HEAT
ADVISORY WILL THUS REMAIN INTACT...AND IS EXTENDED INTO WED AS
COVERED IN THE LONG TERM AFD SEGMENT.
RECORD TEMPERATURES...AS MENTIONED IN THE CLIMATE SEGMENT
BELOW...APPEAR TO BE MOST AT RISK AT CID AND BRL.
VERY WARM AND HUMID CONDITIONS WILL THEN PREVAIL TONIGHT AS THE
SURFACE COOL FRONT SETTLES SOUTH TO ROUGHLY ALONG THE I-80 CORRIDOR
BY DAWN. ASSOCIATED MOISTURE POOLING AND LIGHT WINDS WILL MAKE FOR
UNCOMFORTABLE CONDITIONS. TEMPERATURES WILL BE IN THE UPPER 70S
TO LOWER 80 FOR MUCH OF THE NIGHT...COOLING TO LOWS AROUND SUNRISE
IN THE LOWER TO MID 70S. THERE IS A LOW POTENTIAL FOR CONVECTION
ALONG THIS BOUNDARY...BUT ANYTHING THAT DEVELOPS WILL LIKELY STAY
WELL EAST OF THE FORECAST AREA...WHERE THE CAP WILL BE WEAKER AND
HAVE KEPT MENTIONABLE POPS OUT OF THE FORECAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CDT TUE AUG 27 2013
FORECAST FOCUS ON HOT AND HUMID WEATHER INTO THE WEEKEND BUT THEN
MUCH COOLER BY LABOR DAY.
WEDNESDAY THROUGH SATURDAY...HAVE EXTENDED THE HEAT ADVISORY FOR
MOST OF THE CWA INTO EARLY WEDNESDAY EVENING. A WEAK BACK DOOR COLD
FRONT WILL PUSH ACROSS THE CWA BUT THE MAIN IMPACT WILL BE TO POOL
HIGHER DEWPOINTS ALONG THE BOUNDARY. MOST OF THE CWA WILL HAVE
AFTERNOON TEMPERATURES IN THE LOWER TO MID 90S WITH DEWPOINTS IN THE
LOWER 70S CREATING HEAT INDEX VALUES OF 100 TO 104. THE EXCEPTION
WILL BE OUR FAR NORTH AND NORTHEAST COUNTIES WHERE TEMPERATURES AND
DEWPOINTS WILL BE SOMEWHAT LOWER BEHIND THE FRONT.
THERE WILL BE A BRIEF BREAK ON THURSDAY WITH NORTHEAST WINDS BEHIND
THE FRONT KEEPING HEAT INDEX VALUES BELOW ADVISORY CRITERIA. HOWEVER
BY FRIDAY THE WEAK FRONT RETURNS AS A WARM FRONT AND LIFTS TO OUR
NORTHEAST BRINGING DEWPOINTS BACK INTO THE LOWER 70S AND HIGHS IN
THE LOWER TO MID 90S. HEAT INDEX VALUES WILL ONCE AGAIN PUSH INTO
THE 100 TO 104 RANGE AND THIS COULD POSSIBLY CONTINUE INTO SATURDAY.
THERE ARE SMALL CHANCES OF THUNDERSTORMS FOR BOTH THURSDAY NIGHT AND
FRIDAY NIGHT...BUT CONFIDENCE IS LOW. THIS IS BASED ON THE
OPERATIONAL MODELS INDICATING RIDGE RIDERS MOVING ACROSS THE UPPER
MIDWEST BUT THE BULK OF THE STORMS SHOULD REMAIN ACROSS MN AND WI.
SUNDAY AND LABOR DAY...THE ECMWF FOR 3 STRAIGHT RUNS HAS SHOWN THE
PLUNGE OF MUCH COOLER TEMPERATURES INTO THE MIDWEST AND GREAT LAKES.
IN FACT...THIS MODEL BRINGS THE 2C 850 MB TEMPERATURE LINE TO NEAR
CHICAGO ON LABOR DAY. CONFIDENCE GROWING THAT THIS IS FOR REAL AS
THE GFS/GEM ARE ALSO ON BOARD WITH THIS DEEPENING TROUGH IN THE
EAST...BUT NOT NEARLY AS COLD AS THE ECMWF. THE STRONG COLD FRONT
SHOULD PUSH INTO THE DVN CWA SOMETIME ON SUNDAY AND THE OPERATIONAL
MODELS SUGGEST THE POTENTIAL FOR AT LEAST ISOLATED TO SCATTERED
THUNDERSTORMS ACCOMPANYING THE FRONT...SUNDAY AFTERNOON OR EVENING.
FOR NOW THE GRIDS ARE DRY BUT LATER SHIFTS WILL NEED TO RE-EVALUATE
THE CHANCES OF THUNDERSTORMS. SURROUNDING OFFICES CONSENSUS WAS TO
LOWER TEMPERATURES ON SUNDAY AND LABOR DAY WITH THE FRONT STRONGER
AND ARRIVING SOONER THAN EARLIER DEPICTED.
AT THIS POINT IN THE GAME LABOR DAY LOOKS VERY PLEASANT WITH
COMFORTABLE HUMIDITY AND MAXIMUM TEMPERATURES IN THE 80S...ACTUALLY
AROUND 80 IN OUR FAR NORTHEAST CWA.
THIS COOLER AIR IS SHORT LIVED AS IT APPEARS THE HEAT AND HUMIDITY
QUICKLY RETURN BY THE MIDDLE OF NEXT WEEK.
HAASE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 622 AM CDT TUE AUG 27 2013
CONDITIONS WILL REMAIN VFR TODAY WITH SOUTHWEST WINDS BECOMING
GUSTY DURING THE AFTERNOON FROM 13 TO 20 KTS. A WEAK FRONT WILL
DROP SOUTH INTO THE REGION TONIGHT. MOISTURE POOLING ALONG THIS
BOUNDARY WILL LIKELY LEAD TO SOME MORNING FOG...ESPECIALLY AT CID
AND DBQ. FOR NOW...HAVE GONE WITH PREVAILING MVFR VISIBILITIES
AROUND 8Z TO 9Z TUESDAY MORNING. THERE IS A POTENTIAL FOR PERIODS
LOWER VISIBILITIES INTO IFR RANGE...WHICH MAY BE INCLUDED IN
LATER FORECASTS IF CONFIDENCE INCREASES.
&&
.CLIMATE...
ISSUED AT 357 AM CDT TUE AUG 27 2013
RECORD HIGHS FOR AUGUST 27...
MOLINE.........97 IN 1976
CEDAR RAPIDS...97 IN 1955
DUBUQUE........94 IN 1895
BURLINGTON.....97 IN 1955
RECORD HIGHS FOR AUGUST 28...
MOLINE.........96 IN 1953
CEDAR RAPIDS...96 IN 1955
DUBUQUE........97 IN 1984
BURLINGTON.....96 IN 1945
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR BUCHANAN-DELAWARE-
DUBUQUE-JACKSON.
HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR BENTON-CEDAR-CLINTON-
DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-
LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR HANCOCK-HENDERSON-
MCDONOUGH-MERCER-ROCK ISLAND-WARREN.
HEAT ADVISORY FROM NOON TODAY TO 10 PM CDT THIS EVENING FOR
CARROLL-JO DAVIESS-STEPHENSON.
HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT WEDNESDAY FOR BUREAU-
HENRY IL-PUTNAM-WHITESIDE.
MO...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...HAASE
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
528 AM MDT TUE AUG 27 2013
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 222 AM MDT TUE AUG 27 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE SCALE RIDGE STILL
IN PLACE ACROSS THE CENTRAL CONUS. THERE HAS BEEN A GENERAL
WEAKENING OF THE RIDGE CENTER...WITH CURRENT MAX HEIGHT AROUND
595/596DM. A SHORTWAVE TROUGH OVER EASTERN TEXAS SHOWS GOOD
REFLECTION IN BOTH WV AND HEIGHT FIELD AND COULD BE A MINOR FACTOR
IN TEMPS ON WED.
WITH RIDGE WELL ENTRENCHED OVER OUR CWA...THERE WILL BE VERY LITTLE
CHANGE IN THE HOT/DRY CONDITIONS. MODELS SHOW THE SHORTWAVE TROUGH
OVER EASTERN TEXAS ROUNDING SOUTH AND THEN WESTERN EDGE OF THE RIDGE
CENTER THROUGH WED NIGHT. AS HAS BEEN THE CASE THE LAST FEW
DAYS...THERE SHOULD BE GOOD FORCING AND AT LEAST SOME ELEVATED
INSTABILITY WITH THIS FEATURE. MODEL SOUNDINGS STILL SHOW DEEP DRY
AIR MASS IN PLACE...SO OTHER THAN A BRIEF INCREASE IN CLOUDS AND
SLIGHTLY COOLER TEMPS ALOFT I AM NOT ANTICIPATING PRECIP WITH THIS
FEATURE OVER OUR CWA. GENERAL TREND WILL BE A WEAKENING OF THE LEE
TROUGH WITH GRADIENT SHIFTING EASTWARD. THIS SHOULD SUPPORT LESS
WINDY CONDITIONS THROUGH THE REST OF THE FORECAST PERIOD...THOUGH A
FEW GUSTS IN THE 20-30MPH CANT BE RULED OUT THIS AFTERNOON WITH PEAK
MIXING.
REGARDING TEMPS THROUGH THURSDAY...IT LOOKS LIKE A CONTINUATION OF
THE LAST FEW DAYS WITH HIGHS GENERALLY IN THE UPPER 90S/LOW 100S. THE
ONE EXCEPTION WILL BE WED WHEN HIGHS MAY BE ABOUT 5-7F
COOLER...WHICH STILL PUTS HIGHS ACROSS THE CWA IN THE MID-UPPER 90S
FOR MANY LOCATIONS.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 222 AM MDT TUE AUG 27 2013
MEDIUM RANGE MODEL CONSENSUS IS FOR GRADUAL SLIGHT WEAKENING OF THE
UPPER RIDGE EARLY IN EXTENDED PERIOD. A RELATIVELY SIGNIFICANT
SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN PLAINS AND GREAT LAKES
REGION OVER THE WEEKEND ALONG THE NORTHERN EDGE OF THE RIDGE. AN
ASSOCIATED COLD FRONT WILL MOVE SOUTH/SOUTHWESTWARD TOWARD THE AREA.
THE NEW 00Z ECMWF IS STRONGER WITH THIS SHORTWAVE AND PROGRESSES THE
COLD FRONT FURTHER SOUTHWEST INTO OUR AREA LATE SUNDAY INTO MONDAY.
THE GFS IS LESS AGGRESSIVE WITH SOUTH/SOUTHWEST PROGRESSION OF THE
COLD FRONT BUT DOES SHOW AN INCREASE IN DEEP MOISTURE ACROSS THE
AREA SUNDAY AND MONDAY WITH PWAT VALUES SLIGHTLY EXCEEDING
CLIMATOLOGY. THIS IS ENOUGH TO JUSTIFY KEEPING AT LEAST A VERY LOW
POP IN THE NORTHERN PORTION OF THE FORECAST AREA SUNDAY AND MONDAY.
BY LATE MONDAY A MORE HIGHLY AMPLIFIED PATTERN EVOLVES WITH UPPER
RIDGE STRENGTHENING ONCE AGAIN OVER THE PLAINS BETWEEN PACIFIC
NORTHWEST TROUGH AND DEEPENING TROUGH OVER THE EASTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 528 AM MDT TUE AUG 27 2013
VFR CONDITIONS WILL OCCUR THROUGH THE TAF PERIOD. A SURFACE
TROUGH WILL BE LOCATED NEAR BOTH SITES TODAY AND THIS WILL ALLOW
FOR A WEAKER PRESSURE GRADIENT AND LIGHTER WINDS AS COMPARED TO
THE PREVIOUS TWO DAYS. SOME OCCASIONAL GUSTS BETWEEN 15 AND 20 ARE
POSSIBLE THIS AFTERNOON THROUGH EARLY EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS JACKSON KY
652 AM EDT TUE AUG 27 2013
.UPDATE...
ISSUED AT 652 AM EDT TUE AUG 27 2013
FORECAST IS ON TRACK THIS MORNING...SO NO CHANGES WARRANTED. IT IS
INTERESTING TO NOTE THAT THE LATEST HRRR RUN DOES HINT AT SOME SHOWER
ACTIVITY DRIFTING INTO FAR NORTHEASTERN KENTUCKY THIS EVENING (AFTER
20Z). CONFIDENCE IS STILL WEAK TO INTRODUCE POPS AT THIS TIME...BUT
MAY NEED TO TAKE A CLOSER LOOK AT THE NEED FOR RAIN CHANCES LATER
THIS MORNING IF THE MODELS REMAIN INSISTENT ON BRINGING SOME RAIN
INTO THE AREA.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 257 AM EDT TUE AUG 27 2013
SURFACE/MID/UPPER LEVEL RIDGING WILL CONTINUE TO PROVIDE ANOTHER
QUIET WEATHER DAY ACROSS EASTERN KENTUCKY TODAY. THERE IS A MCS
DROPPING SOUTHEAST ACROSS NORTHERN LAKE MICHIGAN THIS MORNING. THIS
SYSTEM WILL LIKELY WEAKEN AND DISSIPATE AFTER SUNRISE...BUT
SHOWERS/STORMS COULD REDEVELOP ASSOCIATED WITH THE MCV THIS AFTERNOON
INTO THIS EVENING. FORTUNATELY...THE TRAJECTORY SHOULD KEEP THIS
COMPLEX TO OUR NORTHEAST...ALLOWING US TO ENJOY ANOTHER PRECIPITATION
FREE DAY AS OUR AREA REMAINS CAPPED. THE QUIET CONDITIONS WILL
PERSIST INTO TONIGHT WITH MORE VALLEY FOG ANTICIPATED AS DEW POINTS
CONTINUE TO CREEP UPWARDS. A SHORTWAVE TROUGH WILL DROP SOUTHEAST AS
THE RIDGE BREAKS DOWN ON WEDNESDAY. THE TIMING REMAINS IN QUESTION
WITH THIS SYSTEM...BUT OPTING TO GO WITH A COMPROMISE WHICH WOULD
BRING THE SYSTEM INTO EASTERN KENTUCKY LATE IN THE DAY. THIS SHOULD
ALLOW FOR MAINLY A DRY DAY FOR WEDNESDAY WITH THE THREAT OF RAIN
ARRIVING LATE. THERE IS SOME WIND SHEAR PRESENT WEDNESDAY EVENING AND
WITH MODEST INSTABILITY...WE COULD SEE A MARGINAL THREAT FOR
STRONG/DAMAGING WINDS AS SHOWERS AND STORMS PUSH SOUTH/SOUTHEAST.
WILL CONTINUE TO CUT 5 TO 6 DEGREES OFF OF MOS GUIDANCE AS IT HAS
REMAINED MUCH TOO WARM OVER THE PAST SEVERAL DAYS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 455 AM EDT TUE AUG 27 2013
A COLD FRONT WITH A WEAK LOW PRESSURE WAVE ALONG IT WILL DROP SOUTH
THROUGH THE AREA WEDNESDAY NIGHT AND THURSDAY MORNING UNDER NW FLOW
ALOFT. THE OCCURRENCE OF PRECIP REMAINS PROBLEMATIC...WITH CONVECTION
NEEDING TO OVERCOME FAIRLY WARM MID LEVEL TEMPS. IT IS MOST LIKELY
FURTHER TO OUR EAST WITH LIFT BEING AIDED ALONG A WARM FRONT. WILL
CARRY 20-40 PERCENT POPS LOCALLY. PRECIP COULD LINGER INTO THURSDAY
MORNING AS THE FRONTS EXITS TO THE SOUTH. THE EXTENT OF DRYING BEHIND
THE FRONT NOW LOOKS TO BE MUCH MORE IN QUESTION...WITH MODEL RUNS
FROM MONDAY NIGHT ONLY INDICATING MODEST DRYING. IT SHOULD BE ENOUGH
TO RESULT IN DRY WEATHER FROM LATE THURSDAY THROUGH FRIDAY NIGHT.
HOWEVER...THE THREAT OF SHOWERS AND STORMS RETURNS ALREADY ON
SATURDAY AS A STRONG UPPER RIDGE CENTERED TO OUR WEST WEAKENS AND
MID LEVELS COOL SLIGHTLY...AND OUR LOW LEVEL FLOW BEGINS TO PICK UP
FROM THE S AND SW AND BRINGS SLIGHTLY MORE MOIST LOW LEVEL AIR BACK
INTO THE AREA. HAVE USED SLIGHT CHANCE POPS ON SATURDAY AND AGAIN
SUNDAY INTO SUNDAY NIGHT. THE WARM/MOIST ADVECTION PERSISTS INTO
MONDAY...WHEN ANOTHER COLD FRONT APPROACHES FROM THE NW. HAVE USED A
LOW CHANCE POP WITH THE APPROACH OF THE FRONT ON MONDAY. TEMPS WILL
BE VERY WARM THROUGH THE PERIOD...BUT BASED ON A MODEL BLEND...HAVE
UNDERCUT GFS MEXMOS A BIT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 652 AM EDT TUE AUG 27 2013
AFTER SOME MORNING VALLEY FOG...VFR CONDITIONS WILL RETURN BY MID
MORNING AND PERSIST THROUGH THE REMAINDER OF THE DAY AND INTO
TONIGHT. MORE VALLEY FOG IS ANTICIPATED TONIGHT...WITH SOME MVFR
VISIBILITIES DEVELOPING AT KSME AND KLOZ AGAIN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1124 AM EDT TUE AUG 27 2013
.UPDATE...
MORNING CONVECTION HAS SINCE MOVED OFF TO THE SOUTHEAST...LEAVING
SE MI INBETWEEN TWO AREAS OF CONVECTION. THE AREA OF CONCERN FOR
THIS AFTERNOON IS THE ONGOING CONVECTION CURRENTLY MOVING OVER
NORTHERN LOWER MICHIGAN. PRECIP FROM THE UPSTREAM MCS HAS BEEN
DIMINISHING AS IT MOVES INTO DRIER AIR AS SEEN ON THE 12Z APX
SOUNDING. LATEST HRRR RUN CONTINUES TO ADVERTISE THE PROGRESSION
OF CONVECTION ACROSS SE MI...WITH REDEVELOPMENT OF STORMS AFTER
00Z. LATEST MESOANALYSIS AND SATELLITE DOES SHOW MORE MODEST CAPE
VALUES OVER WESTERN PORTIONS OF MICHIGAN WHERE CLOUDS HAVE BEEN
ABLE TO BREAK. THE BETTER CHANCE FOR SEVERE WEATHER IS STILL
EXPECTED TO BE AFTER 00Z...HOWEVER THIS WILL BE DEPENDENT ON HOW
CURRENT SHOWERS HOLD TOGETHER THROUGH THE EARLY AFTERNOON AND
AMOUNT OF INSTABILITY THAT BUILDS ACROSS THE AREA THIS EVENING. STILL
LOOKING AT MAIN THREATS WITH ANY STORMS BEING WINDS AND HEAVY
RAIN.
&&
.AVIATION...ISSUED 710 AM EDT TUE AUG 27 2013
//DISCUSSION...
THUNDERSTORM COMPLEX WILL CONTINUE ACROSS SOUTHEAST MICHIGAN THIS
MORNING. MAIN THREAT FOR THUNDERSTORMS CURRENTLY ANCHORED ALONG THE
LEAD EDGE OF THIS COMPLEX WILL PULL EAST OF ALL TERMINALS OVER THE
NEXT HOUR. A PERIOD OF RAINFALL WITH SOME EMBEDDED THUNDER WILL
LINGER THROUGH LATE MORNING...PROVIDING A WINDOW FOR SOME
INTERMITTENT MVFR VISIBILITY RESTRICTIONS. THE EXISTENCE OF A MOIST
AND WEAKLY UNSTABLE ENVIRONMENT WILL MAINTAIN THE CHANCE FOR
THUNDERSTORM DEVELOPMENT BOTH UPSTREAM AND OVERHEAD FROM MID
AFTERNOON INTO TONIGHT. ANOTHER THUNDERSTORM COMPLEX CURRENTLY
DROPPING SOUTHEAST ACROSS NORTHERN WISCONSIN WILL BE WORTH
MONITORING. OTHERWISE THE HIGHER PROBABILITY FOR GREATER
THUNDERSTORM COVERAGE APPEARS TO BE FOCUSED THIS EVENING AND EARLY
TONIGHT...AND WILL TARGET THIS PERIOD WITH A PROB MENTION.
FOR DTW...ONGOING THUNDERSTORM ACTIVITY WILL REMAIN IN THE VICINITY
OF THE TERMINAL THROUGH THE LATTER HALF OF THE MORNING. POTENTIAL
FOR ADDITIONAL ACTIVITY FROM LATE AFTERNOON INTO THE EARLY PART OF
TONIGHT. AT THIS STAGE...WILL GO AHEAD AN HIGHLIGHT THE MOST
FAVORED TIMEFRAME /AFTER 02Z/.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN THUNDERSTORMS THIS MORNING.
* LOW CONFIDENCE IN THUNDERSTORM POTENTIAL THIS AFTERNOON THROUGH
TONIGHT.
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FT WEDNESDAY
MORNING.
&&
.PREV DISCUSSION...ISSUED 347 AM EDT TUE AUG 27 2013
SHORT TERM... TODAY AND TONIGHT
LARGER SCALE ENVIRONMENT REMAINS VIRTUALLY A CARBON COPY OF THAT
NOTED 24 HOURS AGO...SE MICHIGAN RESIDING ALONG THE NORTHEAST FLANK
OF STRONG UPPER RIDGING ANCHORED OVER THE CENTRAL PLAINS.
WELL-DEFINED THETA-E/MOISTURE AXIS EMANATING SOUTHEAST OF THE MAIN
MOISTURE PLUME SITUATED OVER THE UPPER MS VALLEY NOW DRAPED ACROSS
FAR SOUTHEAST MICHIGAN. EARLY DAY FOCUS TARGETS THE INBOUND
CONVECTIVE COMPLEX CURRENTLY WORKING ACROSS NORTHERN LAKE MICHIGAN.
RECENT RADAR/SATELLITE TRENDS AND HI RES MODEL GUIDANCE SUGGEST SOME
FORM OF THIS COMPLEX WILL WORK ACROSS SE MICHIGAN THIS MORNING
/MAINLY M-59 NORTHWARD/. WHILE THE ARRAY OF MODEL GUIDANCE PROVIDE
A MIXED SIGNAL ON THE RESPONSE...THERE IS A MORE CONCERTED EXPANSION
NOTED AS THE ASSOCIATED MID LEVEL WAVE WORKS ACROSS THE EXISTING
HIGHER THETA-E PLUME. THE MORNING TIMING IS CERTAINLY NOT
IDEAL...BUT RECENT SPC MESOANALYSIS DOES REVEAL ROUGHLY 1000 J/KG OF
EXISTING MUCAPE ALONG AND SOUTHWEST OF A TRI-CITIES TO MOUNT CLEMENS
LINE. THIS WILL SUPPORT A HIGHER END POP /ESPECIALLY NORTH/...WITH
A SMALL WINDOW FOR A FEW STRONGER CELLS TO EMERGE BEFORE THE ENTIRE
COMPLEX EXITS TO THE SOUTHEAST BY LATE MORNING.
BRIEF PERIOD OF SUBSIDENCE AND SOME LAGGING RESIDENCE TIME TO THE
ASSOCIATED CIRRUS CANOPY WILL CONTAIN THE DEGREE OF DESTABILIZATION
FOR A PERIOD OF TIME INTO MIDDAY. HOWEVER...RENEWED THETA-E/WARM
AIR ADVECTION WILL COMMENCE IN THE WAKE OF THIS WAVE AS SOUTHWEST
LOW LEVEL FLOW STRENGTHENS THROUGH THE AFTERNOON AND EVENING. THIS
WILL BE SUFFICIENT FOR A SOLID LATE DAY DIURNAL RESPONSE...HIGHS
SETTLING INTO THE MIDDLE AND UPPER 80S. MUCH LIKE THIS PAST
EVENING...THIS PROCESS ALONE MAY PROVE ADEQUATE TOWARD GENERATING
WIDELY SCATTERED CONVECTION AS INSTABILITY BUILDS. A FIRM CAP WILL
REMAIN PROBLEMATIC...SO BETTER COVERAGE WOULD BE A STRUGGLE UNDER
THIS ENVIRONMENT. THERE IS SUPPORT FOR ANOTHER RIDGE CRESTING
SHORTWAVE TO ANCHOR ANOTHER ROUND OF CONVECTION ACROSS THE UPPER MS
VALLEY AT THE SAME TIME. SLIGHTLY BETTER DIURNAL DYNAMIC RESPONSE
ATTENDANT WITH THIS WAVE...WITH MAINTENANCE AND POSSIBLE UPSCALE
GROWTH EXPECTED ALONG THE MAIN INSTABILITY GRADIENT BACKED BY A
30-35 KNOT VEERING LOW LEVEL JET. 850-300 MB MEAN FLOW AND
PROJECTED CORFIDI VECTORS AGAIN PRESENT LOWER MICHIGAN IN A
FAVORABLE DOWNSTREAM POSITION...MOST FAVORED TIME TONIGHT WITHIN THE
00Z-07Z WINDOW. ORGANIZED CONVECTION BEHIND BULK SHEAR VALUES IN
EXCESS 30 KNOTS WILL BRING THE RISK OF STRONGER WIND GUSTS. A HIGH
PWAT AIRMASS WILL ALSO CONTRIBUTE TO POSSIBLE LOCALLY HEAVY
RAINFALL.
LONG TERM...WEDNESDAY THROUGH MONDAY
WEATHER OVER MICHIGAN WILL CONTINUE TO BE DOMINATED BY FLOW OVER THE
TOP OF THE LARGE UPPER RIDGE OVER THE CENTRAL PLAINS...BEFORE WE
START TO SEE SOME NORTHERN STREAM CONTRIBUTIONS OVER THE HOLIDAY
WEEKEND.
AREA OF LOW PRESSURE AND WEAK FRONT WILL CONTINUE TO DROP THROUGH
SOUTHERN LOWER MICHIGAN WEDNESDAY MORNING. GFS FORECAST SOUNDINGS
FOR DTW START TO SHOW SIGNIFICANT DRYING AND A CAP FORMING AS HIGH
PRESSURE BUILDS IN AFTER 18Z...AND WILL KEEP LOW CHANCES FOR
SHOWERS/TSTORMS ALONG/SOUTH OF M-59 ONLY THROUGH MID-DAY. MODELS
THEN REMAIN IN STRONG AGREEMENT WITH SURFACE HIGH PRESSURE BUILDING
INTO THE CENTRAL GREAT LAKES WEDNESDAY NIGHT THROUGH
THURSDAY...KEEPING THE WEATHER DRY. AIRMASS WILL REMAIN WARM EVEN
BEHIND THE FRONT WITH H850 TEMPERATURES ONLY COOLING TO 16-18 C FOR
WEDNESDAY AND THURSDAY. WITH GOOD INSOLATION THIS SHOULD KEEP
TEMPERATURES IN THE LOW AND MID 80S BOTH DAYS...SLIGHTLY COOLER
OVER THE THUMB WHERE FLOW WILL BE OFF LAKE HURON.
MODELS HAVE THEN KEYED IN ON A SHORTWAVE WITH ORIGINS OVER THE
DESERT SOUTHWEST THEN RIDING ATOP THE RIDGE AND ACROSS NORTHERN
MICHIGAN LATE THURSDAY NIGHT AND FRIDAY. THIS SETUP INITIALLY LOOKS
SLIGHTLY SIMILAR TO TODAY...A FRONT SETTLING IN OVER MICHIGAN AS
UPPER ENERGY OVER CANADA PUSHES SURFACE LOW PRESSURE TOWARDS THE
AREA. THERE ARE STILL QUITE A FEW DIFFERENCES BETWEEN THE MODELS
HOWEVER...BUT THE GENERAL IDEA IS FOR THIS INITIAL WAVE AND
POTENTIALLY A FEW OTHERS TO RIDE OVER THE FRONTAL BOUNDARY THAT WILL
BE DRAPED OVER THE REGION. THIS WILL PROVIDE A CHANCE FOR SHOWERS
AND THUNDERSTORMS FRIDAY AND SATURDAY. THE BIG DIFFERENCE BETWEEN
TODAY`S PATTERN AND THE SET-UP FOR LATER IN THE WEEK WILL BE A
FAIRLY STRONG UPPER TROUGH PUSHING THROUGH CENTRAL CANADA AND
ARRIVING INTO THE GREAT LAKES ON EITHER SATURDAY OR SUNDAY. WHILE
GFS AND EURO DIFFER WITH THE OVERALL SET-UP AND TIMING...THEY DO
AGREE WITH PUSHING A STRONG COLD FRONT DOWN ACROSS THE AREA ON
SUNDAY...PROVIDING A CONTINUATION OF CHANCES FOR SHOWERS/TSTORMS.
DRIER AIRMASS SHOULD WORK INTO THE AREA BEHIND THE FRONT...GFS
ACTUALLY HAS A SECONDARY FRONT DROPPING THROUGH ON MONDAY NOW AS
HIGH PRESSURE SETTLES DOWN INTO THE AREA. TEMPERATURES LOOK TO
REMAIN WARM WITH ABOVE NORMAL TEMPERATURES INTO THE
WEEKEND...ALTHOUGH CONVECTION COULD LIMIT HEATING AT TIMES.
TEMPERATURES SHOULD THEN COOL BEHIND THE FRONT FOR LABOR DAY...WITH
CURRENT FORECAST CARRYING MAX TEMPS ONLY IN THE 70S.
MARINE...
MOIST AND UNSTABLE ENVIRONMENT WILL SUPPORT THUNDERSTORM DEVELOPMENT
THROUGH TONIGHT. OUTSIDE OF THIS THUNDERSTORM RISK...MARINE
CONDITIONS WILL REMAIN QUITE FAVORABLE THROUGH WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SS
AVIATION.....MR
SHORT TERM...MR
LONG TERM....HLO
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DULUTH MN
1054 AM CDT TUE AUG 27 2013
.UPDATE...
AT 1045AM/1545Z...THERE WAS A FRONT STRETCHING FROM WEST TO EAST
JUST SOUTH OF THE FORECAST AREA. THE SOUTHERN FORECAST AREA HAD
CLOUDY SKIES...WHILE THE NORTHERN HALF WAS SUNNY. THERE WAS LITTLE
IF ANY WIND ACROSS THE NORTHLAND. TEMPERATURES WERE IN THE 70S.
I UPDATED THE FORECAST THROUGH THIS EVENING...FOCUSING ON CLOUD
COVER AND THE CHANCES OF SHOWERS AND STORMS. BASED ON THE LATEST
MODELS...ESPECIALLY THE HRRR AND RAP13 MODELS...I BELIEVE THERE
ARE EVEN LOWER CHANCES OF SHOWERS AND STORMS ACROSS THE SOUTHERN
AND SOUTHEASTERN FORECAST AREA THAN PREVIOUSLY FORECASTED. I
LOWERED THE CHANCES OF PCPN...AND MOSTLY CONFINED THE CHANCES
THROUGH THE AFTERNOON TO NW WISCONSIN. IF ANY STORMS DO
DEVELOP...THERE COULD BE A FEW STRONG STORMS WITH SMALL HAIL.
THE CLOUD COVER ACROSS THE SOUTHERN FORECAST AREA IS MOSTLY
REMNANTS FROM MORNING FOG. IT SHOULD CONTINUE TO LIFT AND BREAK
APART THROUGH EARLY THIS AFTERNOON. OTHERWISE...THE NORTHLAND CAN
EXPECT MOSTLY TO PARTLY SUNNY SKIES BY MID AFTERNOON.
TEMPERATURES SHOULD STILL BE QUITE HOT TODAY WITH HIGHS MOSTLY IN
THE UPPER 80S AND LOW 90S EXCEPT CLOSER TO LAKE SUPERIOR. HEAT
INDICES WILL BE AROUND 95 DEGREES ACROSS THE FAR SOUTHERN FORECAST
AREA FOR A BRIEF TIME DURING THE MID TO LATE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 644 AM CDT TUE AUG 27 2013/
AVIATION...12Z TAF ISSUANCE...
WIDESPREAD LOW STRATUS WITH BR/FG THIS MORNING AS UNUSUALLY MOIST
AIR REACHES SATURATION AT SFC. EXPECT IMPROVEMENT AT MOST SITES BY
14Z TO 15Z AS SUNSHINE WORKS ON EVAPORATION OF LOW STRATUS LAYER.
OTHERWISE VFR THROUGH THE DAY ALTHOUGH SPOTTY CONVECTION MAY
REDEVELOP NEAR KDLH/KHYR/KBRD TERMINALS. EXPECT FOG/BR TO
REDEVELOP THIS EVENING AND MAY NEED TO LOWER VIS/CIGS IN NEXT TAF
FCST.
PREV DISCUSSION... /ISSUED 335 AM CDT TUE AUG 27 2013/
SHORT TERM...THROUGH EARLY WEDNESDAY AFTERNOON.
A FRONTAL BOUNDARY WAS DRAPED ACROSS THE REGION THIS
MORNING...FROM SOUTH DAKOTA ACROSS CENTRAL MINNESOTA INTO NORTHERN
WISCONSIN. THIS FEATURE HAS BEEN THE FOCUS FOR CONTINUED
THUNDERSTORMS OVERNIGHT...ALTHOUGH THERE FINALLY DOES SEEM TO BE A
BACK EDGE. LITTLE WAS OCCURRING ACROSS AITKIN/ITASCA
COUNTIES...WITH MOST OF THE STORMS OVER FAR NORTHERN WISCONSIN
BACK INTO THE TWIN PORTS/MOOSE LAKE AREAS. A LARGE AREA OF PWAT
VALUES AROUND 2 INCHES WAS OVER THE AREA WITH FGEN AIDING IN
FORCING. WE EXPECT ADDITIONAL SHOWERS AND STORMS TO FORM OVERNIGHT
INTO THIS MORNING. THE AREA OF STORMS WAS SINKING SOUTHWARD
SOME...SO WE WILL CONTINUE THE FLASH FLOOD WATCH FOR A COUPLE MORE
HOURS AT LEAST. AREAS OVER FAR NORTHERN WISCONSIN CONTINUE TO GET
RAIN...HEAVY IN SPOTS. THE HEAVIEST RAIN TONIGHT SO FAR APPEARS TO
BE OVER THE SANDIER SOILS OF BAYFIELD/DOUGLAS COUNTIES. WE`LL HAVE
TO MONITOR THOUGH...AND MAY NEED TO ISSUE A FLOOD ADVISORY. THERE
IS STILL A SMALL SEVERE THREAT THIS MORNING...MAINLY OVER
NORTHWEST WISCONSIN...WITH DAMAGING WINDS BEING THE MAIN THREAT. A
SMALL SEVERE THREAT WILL LINGER OVER OUR EASTERN WISCONSIN ZONES
INTO THE AFTERNOON AS WELL.
THIS AFTERNOON...THE LOW WILL MOVE EAST AND SOUTH OF THE CWA. IT
WILL REMAIN VERY WARM AND HUMID THOUGH WITH TEMPERATURES IN THE
UPPER EIGHTIES TO LOWER NINETIES. AN ONSHORE WIND OR RAIN WILL
KEEP AREAS AROUND LAKE SUPERIOR INCLUDING THE SOUTH SHORE COOLER.
WE DID NOT ISSUE ANY HEAT ADVISORIES TODAY...AS HEAT INDICES WILL
MAINLY BE IN THE LOWER TO MIDDLE NINETIES.
WE EXPECT IT TO BE DRY TONIGHT WITH SOME FOG POSSIBLE.
WE ALSO KEPT IT DRY ON WEDNESDAY WITH WEAK HIGH PRESSURE IN
CONTROL. IT WILL BE WARM...WITH HIGHS IN THE UPPER EIGHTIES TO
LOWER NINETIES. IT WILL AGAIN BE COOLER AROUND LAKE SUPERIOR.
EXTENDED FORECAST...WEDNESDAY NIGHT THROUGH TUESDAY...
CWA WILL REMAIN UNDERNEATH THE SRN EDGE OF THE WESTERLIES THROUGH
THE WEEK BEFORE CHANGES ARE ADVERTISED BY MED RANGE NWP. ECMWF WAS
OUTLIER YESTERDAY IN ITS AMPLIFICATION OF THE UPPER TROF OVER AND
EAST OF THE REGION THIS WEEKEND. THE GFS/GEM ARE NOW TRENDING IN
THAT DIRECTION AS WELL. CONFIDENCE IS INCREASING THAT AFTER THE
HEAT/HUMIDITY THIS WEEK A RETURN TO CLIMO AND PERHAPS BLO CLIMO
CONDITIONS WILL OCCUR LATE THIS WEEKEND AND EARLY NEXT WEEK.
UNTIL THEN ANOTHER ROUND OF CONVECTIVE ACTIVITY SHOULD OCCUR
THUR/FRIDAY AS A SHORTWAVE TROF TRAVERSES THE NRN FRINGE OF THE
UPPER RIDGE. AS USUAL THE TIMING OF THE SPECIFICS RELATED TO AN
MCC/MCS DEVELOPMENT ARE NOT A HIGH CONFIDENCE ENDEAVOR AT THIS
POINT. THE INITIAL ESTIMATE IS THAT A WARM ADVECTION REGIME WILL
INCREASE INSTABILITY THURSDAY. GEM/GFS/EC POSITION GREATEST PERIOD
OF 85H MSTR TRANSPORT OVER CWA BETWEEN 18Z THUR-06Z FRIDAY.
CONVECTION SHOULD MOVE EAST OF THE CWA FRIDAY WITH DECREASING POPS
WEST TO EAST. AT THIS POINT THE UPPER FLOW BEGINS TO SHIFT TO UPPER
RIDING OVER THE WRN CONUS AND TROUGHING OVER THE ERN GTLKS. TO
ASSIST THIS TRANSFORMATION...A MIGRATORY SHORTWAVE WILL DESCEND
ACROSS THE REGION AMIDST DEEPENING UPPER TROUGH AND SWING A FAIRLY
STRONG COLD FRONT ACROSS THE CWA SATURDAY NIGHT. FCST MAX TEMPS
SATURDAY MAY NEED SIGNIFICANT ADJUSTMENT DUE TO POTENTIAL OF
PREFRONTAL COMPRESSION AND ADVECTION OF SIGNIFICANT LOW LVL THERMAL
RIDGE AHEAD OF STRONG FRONT. EC FCST 85H TEMPS DROP FROM 18C TO 2C
OVER NRN MN ZONES FROM 0Z SUN TO 0Z MON. GEM/GFS ARE MUCH LESS
AGGRESSIVE IN MAGNITUDE BUT DO LOWER TEMPS SUBSTANTIALLY. SHOULD SEE
A POTENTIAL FOR CONVECTION AHEAD OF FRONT SATURDAY EVENING. MAY BE
BLUSTERY BEHIND FRONT SUNDAY BASED ON FCST KINEMATICS AND MECHANICAL
MIXING IN BDRY LYR SUNDAY AFTERNOON. PLEASANT WX APPEARS MORE
PROBABLE WE HEAD INTO THE NEW WEEK.
&&
.POINT TEMPS/POPS...
DLH 82 63 86 65 / 10 10 0 10
INL 86 58 87 64 / 0 0 0 20
BRD 92 65 91 68 / 10 0 0 30
HYR 87 62 90 65 / 30 10 0 10
ASX 79 62 83 62 / 20 10 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1129 AM EDT TUE AUG 27 2013
.SYNOPSIS...
WEAK SHORTWAVES CROSSES TODAY...UNDER NORTHWEST FLOW ALOFT. COLD
FRONT CROSSES WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE VISITS
BRIEFLY FRIDAY BEFORE PATTERN REPEATS.
&&
.NEAR TERM /THROUGH TONIGHT/...
1115 AM UPDATE. ADJUSTED LIKELY POPS TO POTENTIAL NEW MCS
DEVELOPMENT UPSTREAM FAIRLY EARLY THIS AFTERNOON...THEN DROPPING
SOUTH SOUTHEAST.
PREVIOUS DISCUSSION...
HIGH LEVEL CLOUDS ASSOCIATED WITH A DYING MCS ACROSS LAKE MICHIGAN
WILL COVER THE AREA THIS MORNING. NORTHWEST FLOW ALOFT...AND
EMBEDDED SHORTWAVES ARE EVIDENT IN VORT MAX FIELD ON H5 CHARTS.
ALTHOUGH IT LOOKS LIKE CONVECTIVE FEEDBACK...PIECES OF ENERGY
LOOKS REAL ACTING AS FORCING MECHANISMS.
THE HRRR MODEL BRINGS REMNANTS OF GREAT LAKES MCS OVER CKB...EKN
AND NORTHEAST MOUNTAINS THIS AFTERNOON. ANOTHER SHORTWAVE IS
EVIDENT IN H5 CHARTS APPROACHING THE AREA FROM THE NORTHWEST
WEDNESDAY.
NAM AND RUC MODELS SUGGEST AFTERNOON AND EVENING CONVECTION IN QPF
AND SFC CAPE FIELDS ALTHOUGH THE LATER LOOKS OVERDONE BY THE NAM
WITH DEWPOINTS IN THE LOW TO MID 70S. AN AREA OF DEEP LAYERED
SHEAR MOVES INTO SOUTHEAST OH AND PORTIONS OF WV THIS AFTERNOON.
EXPECT CONVECTIVE INITIATION WITH FEW STORMS BUT DO NOT EXPECT
THEM TO BECOME SEVERE.
CODED SKY AND POP GRIDS PER LATEST SATELLITE AND RADAR IMAGES. MID
LEVEL CLOUDS ADVECTING FROM THE NORTHWEST ACROSS SOUTHEAST OHIO
SITES SUCH AS PKB AND HTS EARLY THIS MORNING.
USED THE CONS MOS FOR TEMPERATURE THROUGH THE PERIOD.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ACTIVE WEATHER MAINLY THE FIRST HALF OF THE SHORT TERM PERIOD...WITH
PRECIP CHANCES AND POSSIBLE SUBSEQUENT HYDRO ISSUES PRIMARILY WED
AND WED NIGHT.
WEDNESDAY...AREA REMAINS UNDER NORTHWEST FLOW ALOFT WHILE AT THE SFC
SOUTHWEST WINDS IN PLACE. THOUGH DIFFS EXIST WITH STRENGTH AND
PLACEMENT...CONSENSUS OF NWP OUTPUT IS IN FAIRLY DECENT AGREEMENT
DRAGGING A COUPLE OF VORT MAXES ACROSS THE NORTHEASTERN ZONES FROM
NW TO SE ON WED. FIRST RIPPLE PUSHES INTO THE AREA RIGHT AROUND 12Z
WED AND OVER THE CENTRAL PART OF THE AREA BY 18Z WED. APPEARS THE
BEST OVERALL MOISTURE DEPTH NOT REALLY CO-LOCATED WITH BEST OVERALL
FORCING INITIALLY...WITH THE BEST MOISTURE OVER THE NE ZONES AND
BETTER DYNAMIC FORCING STILL TO THE WEST AND NORTHWEST AT 12Z WED.
HOWEVER OMEGA FIELDS INDICATE AMPLE LIFT THROUGH A DEEP LAYER ACROSS
THE NE ZONES AND WITH PLENTY OF MOISTURE IN PLACE WILL CONTINUE
CATEGORICAL POPS NE ZONES AT THE OUTSET. EXPECT SHOWERS AND
THUNDERSTORMS TO QUICKLY RAMP UP ACROSS THE NORTH AND NW ZONES AS
WELL DURING THE MORNING HOURS WITH THE APPROACH OF THE
AFOREMENTIONED VORT MAX AND ITS ASSOC LIFT...AS WELL AS LARGE SCALE
FORCING FOR ASCENT. BY THE AFTERNOON HOURS THE NEXT VORT MAX ON
NORTHWEST FLOW ALOFT PUSHES INTO THE NW ZONES BY 00Z THU. MODELS
STILL DIFFER ON THE PLACEMENT OF THE ASSOC SFC LOW...ALTHOUGH THEY
ARE TRYING TO COME CLOSER TOGETHER. STILL...LATEST NAM DEPICTS SFC
LOW STILL WELL WEST NEAR CINCINNATI AT 00Z THU WHILE OP GUIDANCE HAS
IT FURTHER EAST/NORTHEAST IN THE AREA OF OUR SE OHIO ZONES. GEFS
MEAN AND ITS MEMBERS SUPPORT THE FURTHER EAST SOLN AS DOES THE SREF
MEAN AND THUS WILL LEAN THE FORECAST IN THIS DIRECTION...WITH THE
LOW AND FRONT ENTERING INTO NW ZONES BY 00Z THU. ALL IN ALL WILL
CONTINUE TO TREND HIGHEST POPS FROM THE NE ZONES TOWARDS THE CENTRAL
AND SOUTHERN ZONES BY 00Z THU. EXPANDED THE COVERAGE OF CATEGORICAL
POPS TO INCLUDE GENERALLY LOCATIONS ALONG AND NORTHEAST OF A
BKW-CRW-PERRY COUNTY OH LINE AS IN THE END MOST IF NOT ALL OF THOSE
LOCATIONS SHOULD SEE SOME MEASURABLE RAINFALL BY DAY/S END ON
WEDNESDAY...THOUGH PINPOINTING THE TIMING ISN/T QUITE SO
STRAIGHTFORWARD. QPF AMOUNTS STILL RUNNING AROUND 0.75IN TO
1.00IN...AND WITH 3-HR FFG GUIDANCE AROUND 2 INCHES THERE IS CONCERN
FOR THE POSSIBILITY OF FLASH FLOODING. STILL NOT QUITE ENOUGH
CONFIDENCE TO ISSUE A WATCH AT THIS POINT AND WILL LET THE DAYSHIFT
TAKE ONE MORE LOOK AT IT. WILL CONTINUE HYDRO CONCERN MENTION
HOWEVER IN HWO AND DID GO AHEAD AND INCLUDE HEAVY RAIN WORDING IN
THE WX GRIDS WED.
PRECIP EXPECTED TO COME TO AN END FROM NW TO SE OVERNIGHT WED NIGHT
AS THE FRONT SWEEPS ACROSS THE AREA. MOST LOCATIONS WILL BE DRY ON
THURSDAY WITH THE FRONT WELL EAST OF THE AREA UNDER A PARTLY CLOUDY
SKY AND HIGHS GENERALLY IN THE MID 80S FOR LOWLAND LOCATIONS. WILL
KEEP INHERITED SLIGHT CHANCE AND LOW CHANCE POPS FOR THE
EAST/SOUTHEAST HIGH TERRAIN WITH A DECENT SLUG OF LLVL MOISTURE
REMAINING ALONG WITH SFC CONVERGENCE ON THE RIDGETOPS PROGGED.
THURSDAY NIGHT ALL LOCATIONS SHOULD DRY OUT WITH THE LOSS OF DAYTIME
HEATING. SFC HIGH PRESSURE CONTINUES TO MOVE EASTWARD AWAY FROM THE
AREA WITH RETURN SOUTHEAST FLOW SETTING UP. THIS...ALONG WITH
ANOTHER S/W TROUGH AND ASSOC VORT MAX MOVING INTO THE NORTHERN ZONES
BY AND AFTER 06Z FRI LENDS SOME POTENTIAL FOR LIGHT SHOWER
REDEVELOPMENT ON THE EAST SLOPES TOWARDS THE DAWN HOURS FRIDAY
MORNING. WILL LEAVE FORECAST DRY FOR NOW.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
GENERALLY FOLLOWED HPC IN EXTENDED WHICH WILL FEATURE QUIETER AND
DRIER WX DESPITE CONTINUING NW FLOW ALOFT. TEMPS RUNNING IN MID
80S AND LOWS GENERALLY IN 60S. GUIDANCE CONT TO RUN ON WARM
SIDE...AS HAS BEEN THE CASE MUCH OF THIS SUMMER. THINK WITH WET
GROUNDS THIS SEASON...FELT HEDGING A LITTLE BELOW GUIDANCE WAS
WARRANTED.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
16Z TUESDAY THRU 12Z WEDNESDAY...
MVFR CEILINGS/HAZE TIL AROUND 18Z...THEN VFR CEILINGS OUTSIDE OF
ANTICIPATED MCS REDEVELOPMENT JUST NORTH OF OUR AREA BY
19Z...DROPPING SOUTH SOUTHEAST REMAINDER OF AFTERNOON...REACHING
SOUTHEAST PORTIONS OF AREA BY 00Z. EXPECT SOUTHWEST PORTIONS OF AREA
INCLUDING HTS TO ESCAPE THIS. OTHERWISE...WILL CARRY PREVAILING
SHRA/TSRA FROM NORTHWEST TO SOUTHEAST FOR ABOUT A 3 HOUR PERIOD AT
OTHER TAF SITES. EXPECT RAPID WEAKENING SHORTLY AFTER 00Z...OF WHICH
AN MVFR CEILING MAY FORM BEHIND THE DYING COMPLEX.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY
THIS AFTERNOON AND EVENING...ALONG WITH DEVELOPMENT OF OVERNIGHT
STRATUS/FOG.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY M M H H H H M M M H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H M H H H H H M M H H H
EKN CONSISTENCY M H H H H H H H H H H H
PKB CONSISTENCY H H H H M H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z WEDNESDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KMC/JMV/30
NEAR TERM...ARJ/JMV
SHORT TERM...30
LONG TERM...30
AVIATION...ARJ/JMV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
959 AM EDT TUE AUG 27 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE OVER THE GULF STATES AND UPPER LEVEL HIGH
PRESSURE IN THE CENTRAL PLAINS WILL DOMINATE THE WEATHER MAP FOR
THE NEXT FEW DAYS. A COLD FRONT WILL TRACK FROM THE WESTERN GREAT
LAKES THROUGH THE OHIO VALLEY ON WEDNESDAY. BEHIND THIS...HIGH
PRESSURE AT THE SURFACE WILL SETTLE OVER NORTHERN OHIO FOR A DRIER
YET STILL WARM PERIOD AT THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID LEVEL RIDGE CENTERED OVER THE CENTRAL UNITED STATES WILL KEEP
OUR REGION IN NORTHWEST FLOW ALOFT. REMNANT MCS CURRENTLY DROPPING
DOWN ACROSS NORTHERN OHIO SHOULD CONTINUE TO WEAKEN THROUGH THE
REST OF THIS MORNING BUT SOME ISOLATED SHOWER/THUNDERSTORM
ACTIVITY WILL LIKELY AFFECT OUR FAR NORTHEAST. DEBRIS CLOUDS
ASSOCIATED WITH THIS WILL LINGER ACROSS AT LEAST THE NORTHEAST HALF
OF OUR FA INTO EARLY AFTERNOON. THIS WILL RESULT IN SOME
UNCERTAINTY AS TO HOW MUCH DESTABILIZATION WE WILL SEE LATER THIS
AFTERNOON. WOULD EXPECT CLOUDS TO THIN/DISSIPATE ENOUGH TO ALLOW
FOR SOME RECOVERY THOUGH...RANGING FROM THE UPPER 80S NORTHEAST TO
NEAR 90 POSSIBLY LOWER 90S ACROSS OUR FAR SOUTHWEST. THIS WILL
RESULT IN ML CAPES IN THE 1500 TO POSSIBLY AS HIGH 2500 J/KG
RANGE LATE THIS AFTERNOON...WITH A SOUTHWEST TO NORTHEAST GRADIENT
ACROSS OUR AREA. BIG QUESTION IS TRACK/TIMING/INTENSITY OF
SECONDARY REMNANT MCS NOW PUSHING DOWN INTO NORTHERN MI. LATEST
NAM/RAP SUGGESTING THE BEST ACTIVITY ASSOCIATED WITH THIS WILL
REMAIN MORE OFF TO OUR NORTHEAST WHILE THE LATEST HRRR IS
INDICATING IT MAY TRACK A LITTLE FARTHER WEST LATE THIS AFTERNOON.
THINK BEST GUESS WOULD BE THAT IT WILL TRACK DOWN ALONG THE
NORTHEAST EDGE OF THE BETTER INSTABILITY GRADIENT...WHICH WOULD
ALLOW FOR IT TO AFFECT AT LEAST OUR NORTHEASTERN AREAS. AS A
RESULT...WILL BUMP UP POPS ACROSS ABOUT THE NORTHEAST THIRD OF
OUR FA...BUT STILL KEEP THEM IN THE HIGH CHANCE CATEGORY DUE TO
THE UNCERTAINTY. BEST DEEP AND MID LAYER SHEAR WILL ALSO REMAIN
ALONG AND NORTHEAST OF OUR FA LATER TODAY SO EXPECT BEST CHANCE
FOR ANY SEVERE STORMS THROUGH THIS AFTERNOON TO BE ACROSS OUR
NORTHEASTERN. THE PRIMARY SEVERE THREAT WOULD BE DAMAGING WINDS
AND POSSIBLY LARGE HAIL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
IF IT WAS NOT STATED IN THE NEAR TERM...MODELS ARE NOT HANDLING
THE ONGOING WEATHER WELL AND DIFFER VASTLY IN THEIR INTERPRETATION
OF THE STATE OF THE WEATHER IN THE SHORT TERM. THE HIGH
TEMPERATURES REACHING INTO THE 90S AND INCREASED MOISTURE THROUGH
THE PERIOD WILL LEAD TO INCREASED THREAT FOR STORMS...ESPECIALLY
ON WEDNESDAY AS A FAIRLY PREDICTABLE COLD FRONT WORKS THROUGH THE
OHIO VALLEY AND SPARKS CONVECTIVE ACTIVITY.
THE LIKELY CHANCES OF STORMS IN THE LATE AFTERNOON AND EVENING
WERE NOT AS CUT AND DRY AS I WOULD PREFER TO CARRY SO POPS WERE
LOWERED FOR THIS TIME TO JUST CHANCE. THE BETTER CHANCE FOR
SHOWERS ON WEDNESDAY WILL OCCUR IN THE NORTHEAST BUT COULD BE
COMPROMISED BY CLOUD COVER LIMITING THE SURFACE BASED INSTABILITY
THAT WILL BE NECESSARY FOR STORMS TO PROGRESS. THIS CLOUD COVER
WILL ALSO PUT THE DAYS HIGH TEMPERATURES IN QUESTION WHERE THE
FORECAST UPPER 80S COULD BE 5 DEGREES TOO HIGH OR SO.
DRIER AIR IN THE WAKE OF THE COLD FRONT WILL BE THE DIFFERENCE IN
THE AIRMASS...NOT NECESSARILY COLDER TEMPERATURES.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
NUMERICAL MODEL SOLNS SHOWING WEAK PERTURBATIONS DROPPING SE
AROUND THE PERIPHERY OF THE MID LEVEL RIDGE. THEREFORE...CAN NOT
RULE OUT VERY LOW POP/ISOLD SHOWERS/THUNDERSTORMS TOWARD THE END
OF THE WEEK INTO NEXT WEEKEND. THESE FEATURES ARE WEAK AND
DIFFICULT TO TIME...AND WITH PROB BEING SO LOW WILL MAINTAIN DRY
FCST THRU FRIDAY NIGHT AND THEN ONLY ALLOW A SLIGHT CHANCE MAINLY
ACROSS THE WEST SATURDAY AFTN. ON SUNDAY A LITTLE MORE SIGNIFICANT
S/W MAY LEAD TO PRECIPITATION. WILL CONTINUE TO LIMIT POPS TO
CHANCE CATEGORY WITH THIS FEATURE. TEMPERATURES REMAIN CLOSE TO 10
DEGREES ABOVE NORMAL WITH HIGHS SAT/SUN UPPER 80S NE TO LOWER 90S
SW.
DETERMINISTIC NUMERICAL MODEL SOLNS HAVE BEEN DIFFERING ON HOW MUCH
THE MID/UPR LEVEL RIDGE PUSHES BACK EAST INTO THE OHIO VALLEY. 00Z
GFS BEING MORE AGGRESSIVE WITH THE RIDGE THAN THE ECMWF AND WAS
HOLDING THE SFC FRONT TO OUR NORTH...WHILE ECMWF WAS PUSHING THE
FRONT THRU ON MONDAY. 12Z DETERMINISTIC GFS RUN HAS TRENDED MORE
TOWARD THE ECMWF...SO WILL ALLOW FOR AN INCREASE IN POPS DURG THE
DAY MONDAY TO ACCOUNT FOR THIS FRONT. TEMPERATURES SLIGHTLY COOLER
MONDAY WITH HIGHS RANGING FROM MID 80S NORTH TO UPPER 80S SOUTH.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
SHRA THAT HAD BEEN DROPPING S TOWARDS KCMH/KLCK EARLY THIS MORNING HAS
SLIPPED TO THE EAST WHILE IT WEAKENED. ADDITIONAL CONVECTION
CONTINUES TO DEVELOP OVER MI AND NW OH. EXPECT THIS CONVECTION TO
DROP SE TODAY AS THE ERN EDGE OF THE H5 RIDGE BREAKS DOWN.
LATEST RUNS OF ALL MODELS TRY AND KEEP THE MAJORITY OF THE PCPN E
OF THE TAFS. THE 00Z NAM IS AN OUTLIER AS IT IS AGGRESSIVE IN
REDEVELOPING CONVECTION ACROSS THE REGION TODAY. BASED ON THE
LATEST RADAR LOOP...IT LOOKS LIKE THE MODELS MAY BE TOO FAR E THIS
AFTN. SO WENT WITH A VCTS AT KCMH/KLCK BEGINNING AT 16Z AND BUILT
THE SCT CONVECTION WWD INTO KILN BY 18Z. KEPT THE WRN TAFS DRY
ATTM.
OVERNIGHT TONIGHT NW FLOW CONTINUES...AS A BACKDOOR CDFNT DROPS
TOWARDS THE REGION. COULD SEE SOME SCT CONVECTION OVERNIGHT. THE
CHC LOOKS LOW ENUF TO KEEP KCVG/KLUK DRY OVERNIGHT.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...JGL
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
801 AM EDT TUE AUG 27 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEASTERN STATES WILL REMAIN IN PLACE
THROUGH MIDWEEK. LOW PRESSURE WILL MOVE EAST ACROSS THE LOWER
GREAT LAKES TONIGHT AND DRAG A WEAK COLD FRONT SOUTH THROUGH THE
AREA ON WEDNESDAY. HIGH PRESSURE WILL RETURN TO THE AREA TOWARD
THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...BASED ON RADAR TRENDS WAS ABLE TO MAKE SIGNIFICANT
CHANGES TO POPS. HAVE A HIGH DEGREE OF CONFIDENCE THAT THE
REMNANTS FROM THE MCS WILL DROP ACROSS MUCH OF THE AREA THROUGH
THE MORNING HOURS. ALSO SHOWERS/THUNDERSTORMS HAVE DEVELOPED
AHEAD OF THE MAIN CONVECTION IN THE KCLE AREA AND OVER THE LAKE AS
WELL AS FAR NWRN OHIO. BOOSTED POPS TO NEAR 100 PERCENT MUCH OF
THE AREA FOR AT LEAST THE MORNING. STILL THINKING WE GET A
RELATIVE BREAK THIS AFTERNOON...BUT STILL A CHANCE...AHEAD OF
ANOTHER ROUND TONIGHT.
ORIGINAL...WIDELY SCATTERED SHOWERS ACROSS THE AREA EARLY THIS
MORNING BUT MOSTLY WEST FROM FDY AREA TO MNN MOVING SOUTH. MAIN
ISSUE FOR TODAY WILL BE THE MCS MOVING SOUTHEAST THROUGH WI.
CIRRUS WILL MOVE INTO NWRN OHIO BY 4 TO 5AM WILL HRRR BRINGING
DYING COMPLEX INTO THE AREA 12-15Z. BROUGHT LIKELY POPS TO THE
AREA FROM KCLE TO KTOL BY 15Z WITH CHANCE POPS ELSEWHERE.
INCREASED POPS TO LIKELY SOUTHEAST AS SYSTEM DROPS SOUTHEAST
THROUGH THE AREA. THROUGH THE AFTERNOON DROPPED POPS BACK TO
CHANCE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TONIGHT FOLLOWED SREF/NAM BLEND WHICH SHOWS A DEVELOPING OR
POSSIBLY ONGOING CONVECTIVE SYSTEM TO OUR NORTHWEST THAT WILL DROP
ACROSS THE AREA THROUGH THE EVENING AND EARLY OVERNIGHT HOURS.
WENT A BIT AGGRESSIVE ON POPS WITH CATEGORICAL POPS ACROSS A LARGE
PORTION OF THE AREA. WILL CONTINUE THIS INTO EARLY WEDNESDAY AS A
WEAK COLD FRONT DROPS THROUGH THE AREA BEFORE DROPPING BACK TO
LIKELY/CHANCE DURING THE AFTERNOON. WEDNESDAY NIGHT AND THURSDAY
DRIER MORE STABLE AIR MOVES IN FROM THE NORTH BEHIND THE COLD
FRONT. CONTINUE DRY THURSDAY NIGHT. FRIDAY PUT IN A SLIGHT CHANCE
WHICH WILL OF COURSE NOT SHOW UP IN THE TEXT. A BIT CONCERNED
ABOUT INCREASING MOISTURE FROM THE NORTHWEST WITH A SHORT WAVE
SHOWING UP IN THE NWLY FLOW ALOFT. INCREASED POPS TO CHANCE NRN
FRINGE FRIDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE AT THE SURFACE WILL BUILD TO THE EAST COAST BY
SATURDAY ALLOWING MOISTURE TO START TO CREEP BACK NORTH INTO THE
REGION WITH A LIGHT SOUTHERLY RETURN FLOW DEVELOPING. THE WESTERN
HALF OF THE FORECAST AREA WILL SEE AT LEAST A CHANCE OF
THUNDERSTORMS WITH SOME INSTABILITY AND SHORTWAVE ENERGY CONTINUING
TO ROUND THE UPPER LEVEL RIDGE. MODELS ARE IN FAIR AGREEMENT WITH
THE 00Z CYCLE IN SHOWING A STRONGER TROUGH ATTEMPTING TO DAMPEN THE
RIDGE OVER THE GREAT LAKES ON SUNDAY WHICH SHOULD YIELD BETTER
CHANCES OF SHOWERS AND THUNDERSTORMS. CONFIDENCE IS LOW IN TIMING
AND PATTERN EVOLUTION THAT FAR OUT SO WILL JUST CARRY A 30 POP FOR
NOW. TEMPERATURES WILL BE ABOVE NORMAL OVER THE WEEKEND WITH A
COOLING TREND FOR EARLY NEXT WEEK AS A COLD FRONT PUSHES SOUTH
ACROSS THE AREA.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
SCATTERED SHOWERS AND THUNDERSTORMS ARE DEVELOPING IN THE CLEVELAND
VICINITY AHEAD OF A LARGER COMPLEX OF SHOWERS AND THUNDERSTORMS
MOVING SOUTHEAST OUT OF MICHIGAN. THIS COMPLEX WILL MOVE SOUTHEAST
ACROSS THE AREA THROUGH ABOUT 15Z WITH AN AREA OF RAIN LINGERING FOR
A COUPLE MORE HOURS BEHIND IT. SOME SITES WILL GUST TO 25-30 KNOTS
WITH THE THUNDERSTORMS.
THIS WILL HELP TO STABILIZE THE AREA FOR A PERIOD OF TIME THIS
AFTERNOON. IT IS SOMEWHAT UNCERTAIN IF THUNDERSTORMS WILL RE-DEVELOP
THIS AFTERNOON AND WILL DEPEND ON THE DEGREE OF CLEARING AND
LINGERING OUTFLOW BOUNDARIES. BEST CHANCES WILL BE IN NW OHIO AFTER
21Z. LOW PRESSURE WILL MOVE THROUGH THE SOUTHERN GREAT LAKES
REGION TONIGHT BRINGING ANOTHER COMPLEX OF SHOWERS AND
THUNDERSTORMS AFTER 04Z. SOME THUNDERSTORMS MAY BE STRONG WITH
HEAVY RAIN OVERNIGHT.
OUTLOOK...MVFR POSSIBLE IN SHOWERS WEDNESDAY MORNING.
&&
.MARINE...
WINDS ON LAKE ERIE WILL MAINTAIN A WESTERLY COMPONENT AT 15 KNOTS OR
LESS TODAY. MULTIPLE ROUNDS OF THUNDERSTORMS ARE POSSIBLE ON THE
LAKE OVER THE NEXT 24 HOURS...ESPECIALLY TONIGHT AS A WAVE OF LOW
PRESSURE MOVES THROUGH THE SOUTHERN GREAT LAKES. THE AREA IS IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS THROUGH TONIGHT. THIS SYSTEM
WILL PULL A COLD FRONT SOUTH ACROSS THE LAKE BEHIND IT ON WEDNESDAY
WITH WINDS SHIFTING TO THE NORTH AT 10-15 KNOTS INTO THURSDAY.
THE NORTHERLY FLOW WILL RESULT IN SOME INCREASE IN WAVE CONDITIONS
IN THE NEARSHORE WATERS AS WAVES BUILD TO 1 TO 3 FEET ON THURSDAY.
HIGH PRESSURE WILL LIGHT WINDS AND WAVES WILL RETURN ON FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
625 AM EDT TUE AUG 27 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEASTERN STATES WILL REMAIN IN PLACE
THROUGH MIDWEEK. LOW PRESSURE WILL MOVE EAST ACROSS THE LOWER
GREAT LAKES TONIGHT AND DRAG A WEAK COLD FRONT SOUTH THROUGH THE
AREA ON WEDNESDAY. HIGH PRESSURE WILL RETURN TO THE AREA TOWARD
THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...BASED ON RADAR TRENDS WAS ABLE TO MAKE SIGNIFICANT
CHANGES TO POPS. HAVE A HIGH DEGREE OF CONFIDENCE THAT THE
REMNANTS FROM THE MCS WILL DROP ACROSS MUCH OF THE AREA THROUGH
THE MORNING HOURS. ALSO SHOWERS/THUNDERSTORMS HAVE DEVELOPED
AHEAD OF THE MAIN CONVECTION IN THE KCLE AREA AND OVER THE LAKE AS
WELL AS FAR NWRN OHIO. BOOSTED POPS TO NEAR 100 PERCENT MUCH OF
THE AREA FOR AT LEAST THE MORNING. STILL THINKING WE GET A
RELATIVE BREAK THIS AFTERNOON...BUT STILL A CHANCE...AHEAD OF
ANOTHER ROUND TONIGHT.
ORIGINAL...WIDELY SCATTERED SHOWERS ACROSS THE AREA EARLY THIS
MORNING BUT MOSTLY WEST FROM FDY AREA TO MNN MOVING SOUTH. MAIN
ISSUE FOR TODAY WILL BE THE MCS MOVING SOUTHEAST THROUGH WI.
CIRRUS WILL MOVE INTO NWRN OHIO BY 4 TO 5AM WILL HRRR BRINGING
DYING COMPLEX INTO THE AREA 12-15Z. BROUGHT LIKELY POPS TO THE
AREA FROM KCLE TO KTOL BY 15Z WITH CHANCE POPS ELSEWHERE.
INCREASED POPS TO LIKELY SOUTHEAST AS SYSTEM DROPS SOUTHEAST
THROUGH THE AREA. THROUGH THE AFTERNOON DROPPED POPS BACK TO
CHANCE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
TONIGHT FOLLOWED SREF/NAM BLEND WHICH SHOWS A DEVELOPING OR
POSSIBLY ONGOING CONVECTIVE SYSTEM TO OUR NORTHWEST THAT WILL DROP
ACROSS THE AREA THROUGH THE EVENING AND EARLY OVERNIGHT HOURS.
WENT A BIT AGGRESSIVE ON POPS WITH CATEGORICAL POPS ACROSS A LARGE
PORTION OF THE AREA. WILL CONTINUE THIS INTO EARLY WEDNESDAY AS A
WEAK COLD FRONT DROPS THROUGH THE AREA BEFORE DROPPING BACK TO
LIKELY/CHANCE DURING THE AFTERNOON. WEDNESDAY NIGHT AND THURSDAY
DRIER MORE STABLE AIR MOVES IN FROM THE NORTH BEHIND THE COLD
FRONT. CONTINUE DRY THURSDAY NIGHT. FRIDAY PUT IN A SLIGHT CHANCE
WHICH WILL OF COURSE NOT SHOW UP IN THE TEXT. A BIT CONCERNED
ABOUT INCREASING MOISTURE FROM THE NORTHWEST WITH A SHORT WAVE
SHOWING UP IN THE NWLY FLOW ALOFT. INCREASED POPS TO CHANCE NRN
FRINGE FRIDAY NIGHT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HIGH PRESSURE AT THE SURFACE WILL BUILD TO THE EAST COAST BY
SATURDAY ALLOWING MOISTURE TO START TO CREEP BACK NORTH INTO THE
REGION WITH A LIGHT SOUTHERLY RETURN FLOW DEVELOPING. THE WESTERN
HALF OF THE FORECAST AREA WILL SEE AT LEAST A CHANCE OF
THUNDERSTORMS WITH SOME INSTABILITY AND SHORTWAVE ENERGY CONTINUING
TO ROUND THE UPPER LEVEL RIDGE. MODELS ARE IN FAIR AGREEMENT WITH
THE 00Z CYCLE IN SHOWING A STRONGER TROUGH ATTEMPTING TO DAMPEN THE
RIDGE OVER THE GREAT LAKES ON SUNDAY WHICH SHOULD YIELD BETTER
CHANCES OF SHOWERS AND THUNDERSTORMS. CONFIDENCE IS LOW IN TIMING
AND PATTERN EVOLUTION THAT FAR OUT SO WILL JUST CARRY A 30 POP FOR
NOW. TEMPERATURES WILL BE ABOVE NORMAL OVER THE WEEKEND WITH A
COOLING TREND FOR EARLY NEXT WEEK AS A COLD FRONT PUSHES SOUTH
ACROSS THE AREA.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE TODAY
AS THE ATMOSPHERE CONTINUES TO MOISTEN. EARLY MORNING HZ/BR ALSO
POSSIBLE 09-13Z WITH INCREASING DEWPOINTS. EARLY THIS MORNING WE
ARE WATCHING A COMPLEX OF THUNDERSTORMS OVER NE WISCONSIN WHICH
WILL TAKE AIM AT NRN OHIO AFTER 12Z. EXPECTING THIS COMPLEX TO
UNDERGO SOME WEAKENING AS IT APPROACHES. REMNANTS OF THIS FEATURE
WILL RESULT IN ADDITIONAL STORM DEVELOPMENT EARLY THIS AFTERNOON
AND HAVE INCLUDED A VCTS IN ALL SITES. TIMING REMAINS IN QUESTION
BUT EXPECT PRETTY GOOD CHANCES FOR A THUNDERSTORM AT SOME POINT
THIS AFTERNOON...ESPECIALLY AT CLE/MFD/CAK/YNG WITH THE POTENTIAL
FOR SOME THUNDERSTORMS TO BE STRONG TO SEVERE.
MODELS ARE IN PRETTY GOOD AGREEMENT THAT WE ARE LOOKING FOR ANOTHER
ROUND OF THUNDERSTORMS TOWARDS THE END OF THE TAF CYCLE (04-12Z) AS
LOW PRESSURE TRACKS THROUGH THE SOUTHERN GREAT LAKES. THESE
THUNDERSTORMS COULD ONCE AGAIN BE STRONG WITH HEAVY RAINFALL
POSSIBLE.
OUTLOOK...MVFR PROBABLE WITH SHRA/TSRA BR TUESDAY AFTERNOON THROUGH
WEDNESDAY.
&&
.MARINE...
WINDS ON LAKE ERIE WILL MAINTAIN A WESTERLY COMPONENT AT 15 KNOTS OR
LESS TODAY. MULTIPLE ROUNDS OF THUNDERSTORMS ARE POSSIBLE ON THE
LAKE OVER THE NEXT 24 HOURS...ESPECIALLY TONIGHT AS A WAVE OF LOW
PRESSURE MOVES THROUGH THE SOUTHERN GREAT LAKES. THE AREA IS IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS THROUGH TONIGHT. THIS SYSTEM
WILL PULL A COLD FRONT SOUTH ACROSS THE LAKE BEHIND IT ON WEDNESDAY
WITH WINDS SHIFTING TO THE NORTH AT 10-15 KNOTS INTO THURSDAY.
THE NORTHERLY FLOW WILL RESULT IN SOME INCREASE IN WAVE CONDITIONS
IN THE NEARSHORE WATERS AS WAVES BUILD TO 1 TO 3 FEET ON THURSDAY.
HIGH PRESSURE WILL LIGHT WINDS AND WAVES WILL RETURN ON FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...KEC
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
644 AM CDT TUE AUG 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT TUE AUG 27 2013
..CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER
TROUGH JUST OFF THE PACIFIC NORTHWEST COAST AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUE TO ROTATE AROUND THE RIDGE...TRACKING FROM ARIZONA INTO THE
DAKOTAS AND THE FORECAST AREA. PRECIPITABLE WATER VALUES MAX OUT IN
THE 2-2.25 INCH RANGE FROM CENTRAL MN INTO NORTHERN WI PER RAP
ANALYSIS. CLUSTERS OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
MONSOONAL SHORTWAVES AS WELL AS 850MB-700MB MOISTURE TRANSPORT HAVE
BEEN TRACKING THROUGH THIS PRECIPITABLE WATER MAX. BLOWOFF FROM THIS
CONVECTION ENCOMPASSES MUCH OF THE FORECAST AREA. AIRMASS IS VERY
WARM ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THE 00Z MPX RAOB
REPORTED A 25C 850MB TEMP AND 27C 925MB TEMP...WHICH TRANSLATED TO A
HIGH YESTERDAY OF 97F AT MSP. BETWEEN THE HOT TEMPERATURES
YESTERDAY...THE BLOWOFF...A LIGHT SOUTHERLY BREEZE AND DEWPOINTS
HOLDING IN THE LOW 70S...TEMPERATURES HAVE STRUGGLED TO DROP THIS
MORNING. READINGS ARE STILL MAINLY BETWEEN 75 AND 80. SURFACE
PRESSURE ANALYSIS SHOWED LOW PRESSURE NEAR MONTEVIDEO MN...WITH A
WARM FRONT STRETCHING INTO TAYLOR COUNTY AND A COLD FRONT BACK INTO
CHAMBERLAIN SOUTH DAKOTA.
..HAZARDS..
1. HEAT. HAVE KEPT ALL GOING HAZARDS INTACT. CONSIDERED UPGRADING
FLOYD...CHICKASAW AND FAYETTE COUNTIES TO EXCESSIVE HEAT
WARNING...BUT HEAT INDICES APPEAR MARGINAL TO DO SO.
2. STORMS. SEVERE POTENTIAL...PARTICULARLY THIS AFTERNOON NORTH AND
EAST OF I-94.
3. FOG LATE TONIGHT...WHICH COULD END UP BEING DENSE...ESPECIALLY
WHERE IT RAINS.
..SYNOPTIC OVERVIEW..
THE SUBTROPICAL RIDGE OVER KANSAS AND MISSOURI IS PROGGED TO STAY
PUT THROUGH TONIGHT. HOWEVER...A CHANGE IN THE UPPER AIR PATTERN IS
TO HAVE SOME RIDGE BUILD NORTH TONIGHT INTO THE DAKOTAS. THIS...IN
TURN...HELPS TO TURN THE FLOW MORE NORTHWESTERLY OVER THE FORECAST
AREA. A SERIES OF MONSOONAL SHORTWAVES ROTATING AROUND THE RIDGE ARE
FORECAST TO COME THROUGH NORTHEASTERN PORTIONS OF THE FORECAST AREA
THROUGH TONIGHT...HELPING TO PUSH THE SURFACE LOW AND COLD FRONT
SOUTHEAST THROUGH THE ENTIRE AREA BY 12Z WEDNESDAY.
..DETAILS..
PRECIPITATION...WITH 850MB AND 700MB MOISTURE TRANSPORT FOCUSED INTO
THE AREA NORTHEAST OF I-94 THIS MORNING...THERE REMAINS POTENTIAL
FOR CONVECTION JUST FROM THIS THERMODYNAMIC FORCING. HOWEVER...THINK
THE GREATER POTENTIAL FOR CONVECTION WILL COME THIS AFTERNOON AS A
SHORTWAVE PRESENTLY WEST OF FARGO COMES THROUGH CENTRAL WISCONSIN AT
PEAK HEATING. VERY GOOD MODEL CONSENSUS FOR CONVECTION TO OCCUR
NORTHEAST OF I-94 IN THE AFTERNOON...WITH EVEN A POSSIBILITY OF IT
EXTENDING BACK TOWARDS LA CROSSE. THIS CONVECTION WILL SLIDE
SOUTHEAST OF THE AREA DURING THE EVENING...WITH ALL OF IT LIKELY OUT
BY 03Z. DRY CONDITIONS ARE EXPECTED ELSEWHERE DUE TO CAPPING AND
LIMITED CONVERGENCE ON THE COLD FRONT...AND DRY CONDITIONS ARE
ANTICIPATED ONCE THE FRONT PASSES AS SUBSIDENCE AND DRYING WORK IN.
SEVERE POTENTIAL...0-6KM SHEAR IS DECENT IN THE MORNING...35-45 KT
NORTHEAST OF I-94. HOWEVER...NOT ANTICIPATING MUCH OF THE MORNING
CONVECTION TO BE ABLE TO UTILIZE THIS SHEAR. DURING THE AFTERNOON
WHEN CAPE IS AT ITS HIGHEST...THE 0-6KM SHEAR IS WEAKENING TO 30-35
KT. NONETHELESS...WITH MLCAPES OF 2000-2500 FT COMBINING WITH THIS
SHEAR SHOULD ALLOW FOR SOME STORM ORGANIZATION...LIKELY IN THE FORM
OF MULTICELLS WITH A SUPERCELL POSSIBLE. FREEZING LEVELS UP NEAR
16000 FT SHOULD LIMIT HAIL...BUT CERTAINLY DAMAGING WINDS AND VERY
HEAVY RAIN ARE POSSIBLE GIVEN THE UNSEASONABLY WARM...MOIST
ENVIRONMENT.
HEAT...925MB TEMPERATURES TODAY ARE PROGGED VERY SIMILAR TO
YESTERDAY AHEAD OF THE COLD FRONTAL PASSAGE...RUNNING BETWEEN
27-29C. SO WE SHOULD SEE READINGS THAT ARE SIMILAR AS WELL. AROUND
CHARLES CITY THE READINGS APPROACH 30C...SO IT IS POSSIBLE THEY WILL
END UP A LITTLE WARMER.
LASTLY...A POTENTIAL ISSUE TO DEAL WITH LATE IN THE NIGHT IS FOG.
THE FRONT THAT COMES THROUGH TONIGHT IS QUITE SHALLOW AND STRUGGLES
TO GET THESE HIGHER DEWPOINTS OUT OF HERE. WITH COOLER AIR COMING IN
BEHIND THE FRONT AND LIGHT SURFACE WINDS...WE MAY END UP WITH SOME
SHALLOW FOG...PARTICULARLY SOUTHWEST OF I-94. SREF VISIBILITY PROGS
SHOW THIS NICELY. HAVE RAISED THE FOG COVERAGE AND WILL HAVE TO
WATCH FOR POSSIBLE DENSE FOG.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE AUG 27 2013
..HAZARDS..
1. HEAT. DEWPOINTS LOOK A LITTLE BIT HIGHER FOR WEDNESDAY...THOUGH
TEMPERATURES WILL NOT BE NEARLY AS WARM THE PAST FEW DAYS.
THEREFORE...HEAT INDICES ONLY TOP OUT IN THE 90S...JUST BELOW
ADVISORY CRITERIA. FARTHER AHEAD...AN ADVISORY IS LOOKING MORE
LIKELY FOR FRIDAY...PARTICULARLY NORTHEAST IOWA AND FAR SOUTHWEST
WI. NO ADVISORIES NEEDED NOW FOR THE WEEKEND.
..SYNOPTIC OVERVIEW..
27.00Z MODEL GUIDANCE IN GOOD AGREEMENT SHOWING THAT THE SUBTROPICAL
RIDGE OVER KANSAS AND MISSOURI WILL RETROGRADE WESTWARD INTO THE
FOUR CORNERS REGION BY SATURDAY. THE LAST COUPLE OF DAYS MODELS HAD
SUGGESTED THAT THE RIDGE WOULD HEAD BACK EAST. HOWEVER...THIS IS NOW
DELAYED BECAUSE OF A SHORTWAVE TROUGH COMING OUT OF SOUTHWEST CANADA
ON FRIDAY THAT ENDS UP DIGGING INTO THE GREAT LAKES REGION ON
SUNDAY. THE 26.00Z ECMWF WAS FIRST TO SHOW THIS AND NOW ALL MODELS
HAVE CAPTURED ONTO THE IDEA. THE ONLY QUESTION NOW IS TIMING AND
AMPLIFICATION OF THIS TROUGH...WHICH THERE IS A DECENT SPREAD ON
COME SUNDAY.
..DETAILS..
WITH THE FRONTAL BOUNDARY SOUTH OF THE AREA ON WEDNESDAY AND HIGH
PRESSURE IN PLACE...HAVE CONTINUED THE DRY FORECAST. AS MENTIONED IN
THE HAZARDS SECTION...HIGHER DEWPOINTS DOES RAISE CONCERN FOR
EXTENSION IN THE HEAT ADVISORY. HOWEVER...925MB TEMPS OF 25-27C WILL
RESULT IN COOLER HIGHS...KEEPING HEAT INDICES BELOW ADVISORY LEVEL.
A SERIES OF SHORTWAVES ARE PROGGED TO COME ACROSS THE NORTHERN
PLAINS AND INTO THE NORTHERN GREAT LAKES REGION WEDNESDAY NIGHT
THROUGH FRIDAY. THE SHORTWAVES WEDNESDAY NIGHT AND THURSDAY ARE
PROGGED TO HELP BRING THE COLD FRONT BACK TOWARDS US...AND
ISENTROPIC LIFT/MOISTURE TRANSPORT OVER THE FRONT RESULTS IN CONCERN
FOR CONVECTION. THE GREATEST CHANCES FOR CONVECTION WEDNESDAY NIGHT
AND THURSDAY WILL TRACK JUST NORTH OF THE AREA...CLOSER TO THE
SHORTWAVES...BUT THE ISENTROPIC LIFT COULD SPREAD SOME SHOWERS AND
THUNDERSTORMS DOWN INTO THE FORECAST AREA...ESPECIALLY WEST OF THE
MS RIVER AND OVER NORTH CENTRAL WISCONSIN. HAVE CONTINUED 20-30
PERCENT CHANCES. THESE CHANCES GRADUALLY ENCOMPASS MORE OF THE AREA
HEADING INTO THURSDAY NIGHT AND ESPECIALLY FRIDAY. ON FRIDAY...
MODELS ARE IN GOOD AGREEMENT SHOWING A SHORTWAVE COMING THROUGH
CENTRAL MN AND SOUTHEAST INTO THE FORECAST AREA AT THE TIME OF PEAK
HEATING. 0-6KM SHEAR ONLY PROGGED 20-25 KT...SO NOT THINKING SEVERE
AT THIS TIME. TEMPERATURES WILL COOL DOWN BRIEFLY ON THURSDAY
BETWEEN CLOUDS/POTENTIAL CONVECTION AND 925MB TEMPS OF 22-26C.
HOWEVER...TEMPERATURES LOOK TO SHOOT BACK UP ON FRIDAY AHEAD OF THAT
SHORTWAVE COMING THROUGH. COOLING WILL OCCUR FRIDAY NIGHT WITH
PASSAGE OF THE SHORTWAVE TROUGH.
HEADING INTO LABOR DAY WEEKEND...WARM AIR COULD TRY TO SURGE BACK
INTO THE AREA ON SATURDAY...AHEAD OF THE MORE POTENT SHORTWAVE
TROUGH CROSSING SOUTH CENTRAL CANADA. ONLY HAVE SOME VERY LOW
CHANCES OF PRECIPITATION IN...MAINLY TOWARDS CENTRAL WISCONSIN WHERE
ISENTROPIC LIFT LOOKS GREATEST. BIGGEST CONCERN COMES SUNDAY AND
MONDAY WITH HOW MUCH COLD AIR COMES IN BEHIND THE COLD FRONT
ASSOCIATED WITH THE SHORTWAVE TROUGH...ALONG WITH TIMING TOO. 27.00Z
ECMWF IS VERY AGGRESSIVE DIVING 925MB TEMPS DOWN TO 6C BY 12Z
MONDAY. COMPARE THIS TO THE 27.00Z GFS WHICH ARE 16-20C...DRAMATIC
DIFFERENCE. THUS...TEMPERATURE FORECASTS ARE LOW CONFIDENCE. GIVEN
THE COOLER SIGNAL IN THE ECMWF...FELT IT WAS APPROPRIATE TO LOWER
HIGHS...LOWS AND DEWPOINTS FOR SUNDAY THROUGH MONDAY NIGHT ABOUT 5
OR SO DEGREES FROM THE PREVIOUS FORECAST. RAIN CHANCES LOOK MINIMAL
FOR SUNDAY THROUGH MONDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 642 AM CDT TUE AUG 27 2013
A COLD FRONT WILL PROVIDE A CHANCE OF SHOWERS AND THUNDERSTORMS
GENERALLY NORTH AND EAST OF INTERSTATE 94. AS A RESULT...DID NOT
INCLUDE THESE IN EITHER TAF SITE. SOUTHWEST WINDS OF AROUND
10 KNOTS WILL SHIFT TO WEST AROUND 27.23Z...AND THEN BECOME
NORTHWEST AND DECREASE TO AROUND 5 KNOTS AFTER 28.03Z.
FOR THE PAST 3 DAYS...THE SREF HAS INDICATED THAT WIDESPREAD FOG
WILL DEVELOP ACROSS THE AREA. SOME OF MOS VALUES INDICATE THAT
THIS FOG MAY BECOME DENSE. HOWEVER LIGHT NORTHEAST AND EAST WINDS
ALOFT ARE NORMALLY NOT THAT FAVORABLE FOR DENSE FOG. AS A RESULT...
JUST LOWERED IT DOWN TO 1 MILE AT THIS TIME.
&&
.CLIMATE...
ISSUED AT 334 PM CDT MON AUG 26 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR WIZ017-029-034-
042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR WIZ032-033-
041.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR MNZ086-087-094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR MNZ079-088-
096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
634 AM CDT TUE AUG 27 2013
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 336 AM CDT TUE AUG 27 2013
AREA RADARS CONTINUE TO SHOW STORMS FORM OVER MN AND MOVE INTO/
THROUGH NORTHERN WI. SO FAR STORMS HAVE NOT TRAINED OVER SAME
LOCATION WITH HEAVY RAIN FALLING IN NARROW BANDS. STORMS NOW OVER
NW WI...TO MOVE INTO CWA AFT 10Z. WILL NEED TO BE WATCHED AS SHEAR
INCREASING OVER NORTHERN WI ATTM. STORMS NOT EXPECTED INTO FFA AREA
UNTIL 12Z OR AFTER...SO HAVE DECIDED TO DROP HEADLINE. MAIN ISSUE
OF THIS FORECAST IS PCPN TRENDS.
FORCING FOR STORMS OVERNIGHT FGEN/WAA SHIFTING EAST WITH 850 WINDS
BECOMING WESTERLY BY MORNING. TODAYS FORCING TO BE MORE TIED INTO
RIDGE RIDING DISTURBANCES AND LOCATION OF BOUNDARY. MODELS SUGGEST
BOUNDARY TO SHIFT SLOWLY SOUTH THROUGH CWA TODAY. HRRR NOT DOING
TO BAD ATTM...WITH CURRENT PCPN NORTH. HRRR TRENDS TO DIMINISH
PCPN DURING MORNING HOURS...THEN REDEVELOP OVER REGION FROM
MARINETTE TO TOMAHAWK BY MID AFTERNOON. AGAIN AREA IN SLIGHT RISK
FOR SEVERE WITH SIG INSTABILITY.
HIGH PRESSURE TO BUILD INTO STATE LATER TONIGHT AND WED...BRINGING A
BRIEF DRYING TREND.
TEMPS TODAY AGAIN HIGHLY DEPENDENT ON CLOUDS. WINDS BECOME A BIT
MORE ONSHORE TOO AS BOUNDARY SHIFTS SOUTH. HAVE TRENDED A BIT
COOLER NORTH AND FAR EAST...STAYING CLOSE TO YESTERDAYS READINGS.
AGAIN HEAT INDEX READINGS HIT 100 FOR COUPLE HOURS FAR SOUTHWEST
CWA. WILL STAY WITH SPS TO HIGHLIGHT AND NOT ISSUE ANY HEADLINE.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 336 AM CDT TUE AUG 27 2013
MDLS ARE IN GENERAL AGREEMENT ON THE LONG-RANGE MEAN FLOW ACROSS
THE CONUS WITH UPR TROFS JUST OFF THE WEST COAST AND WRN ATLANTIC
WITH AN UPR RDG SITUATED OVER THE CNTRL/SRN PLAINS. QUESTIONS
ARISE BY LATE IN THE WEEKEND WHETHER THE UPR RDG WL REMAIN
SOMEWHAT FLAT OR BUILD NWD THRU THE ROCKIES AS AN UPR TROF DIGS
TOWARD THE NE CONUS. AFTER A BRIEF RESPITE FROM THE HEAT/HUMIDITY
WED NGT/THU...RETURN FLOW MAKES A COMEBACK BRINGING PCPN CHCS BACK
TO THE REGION THU NGT/FRI WITH SEVERAL OTHER CHCS FOR PCPN THRU
THE UPCOMING WEEKEND.
NE WI TO REMAIN ON THE WRN FRINGE OF THE SFC HI THRU WED NGT...
THEREBY KEEPING WINDS LIGHT AND LEADING TO THE POTENTIAL OF MORE
FOG. THE EXACT EXTENT OF THE FOG IS A BIT UNCERTAIN AS MID AND UPR
LEVEL CLOUDS COULD BE MOVING INTO CNTRL WI AFTER MIDNGT AS WAA
BEGINS TO SPREAD NE FROM THE MIDWEST. HAVE KEPT FOG PATCHY FOR NOW
WITH MIN TEMPS RANGING FROM THE UPR 50S TO LWR 60S NORTH...60 TO
65 DEGS ELSEWHERE.
AS THE SFC HI DRIFTS TOWARD THE ERN GREAT LAKES ON THU...RETURN
FLOW SETS UP ACROSS WI WITH DEW POINTS STARTING TO CREEP UP ONCE
AGAIN. IN ADDITION...MDLS ARE SHOWING A SHORTWAVE TROF TOPPING THE
UPR RDG AND SLIDING E-SE TOWARD THE WRN GREAT LAKES BY LATE IN THE
DAY. BETWEEN THE LIFT FROM THE WAA AND THE START OF MID-LEVEL
FORCING FROM THE SHORTWAVE TROF...CANNOT RULE OUT A FEW SHWRS OR
TSTMS OVER CNTRL WI DURING THE AFTERNOON. AWAY FROM THE IMMEDIATE
LAKESHORE...EXPECT MAX TEMPS TO GENERALLY REACH THE LWR TO MID 80S.
THE SHORTWAVE TROF IS FCST TO MOVE SE INTO THE GREAT LAKES REGION
THU NGT AND HELP TO DRAG A WEAK FRONTAL BOUNDARY INTO NRN WI DURING
THE OVRNGT HOURS. WHILE INSTABILITY IS MARGINAL...SHEAR IS FAIRLY
STRONG TO SUSTAIN UPDRAFTS AND THERE IS A DIFFLUENT FLOW ALOFT
ADDING TO THE LIFT. PREFER TO GO WITH A MORE UNIFORM HI CHC POP
FOR NE WI...BUT BELIEVE THAT NRN PARTS OF THE STATE WOULD SEE
HIGHER QPF AMOUNTS AS FORCING A BIT STRONGER DUE TO THE PROXIMITY
OF THE SHORTWAVE TROF. THIS FRONTAL BOUNDARY WL SLOWLY SAG THRU WI
ON FRI...BUT BEGIN TO SLOW DOWN AS IT ENCOUNTERS THE EDGE OF THE
BROAD CNTRL/SRN PLAINS UPR RDG. A CONTINUED CHC OF SHWRS/TSTMS
ACROSS THE FCST AREA IS NECESSARY...ALTHO THE NORTH MAY SEE THE
PCPN COME TO AN END DURING THE AFTERNOON IF THE BOUNDARY CAN SLIP
FAR ENUF TO THE SOUTH. ANTICIPATED CLOUDS SHOULD HELP TO HOLD
TEMPS IN CHECK...BUT WITH 8H TEMPS STILL NEAR +20C...ANOTHER DAY
IN THE LWR TO MID 80S CAN BE EXPECTED.
THE MAIN QUESTION FOR THE FRI NGT/SAT TIME FRAME IS WHETHER THIS
BOUNDARY WL PUSH FAR ENUF SOUTH BEFORE STALLING TO AVOID THE
MENTIONING OF MORE PCPN. MDLS HAVE VARIOUS SOLUTIONS HERE...BUT
THE LATEST TRENDS DO SHOW THIS BOUNDARY SAGGING FAR ENUF TO AT
LEAST MINIMIZE THE PCPN CHCS OVER THE NORTH. NOT ENUF CONFIDENCE
TO COMPLETELY PULL THE POPS...BUT AT LEAST WL ATTEMPT TO TIER POPS
MORE FROM SOUTH TO NORTH.
A LOT OF UNCERTAINTY REMAINS FOR THE SUNDAY PERIOD AS THE ECMWF
BUILDS THE UPR RDG NWD THRU THE ROCKIES FASTER THAN THE OTHER
MDLS. THE ECMWF`S SOLUTION WOULD SEND A CDFNT THRU WI ABOUT 12
HOURS FASTER...THUS CLEARING THINGS OUT FOR SUNDAY AS OPPOSED TO A
SUNDAY FROPA ADVERTISED BY THE GFS/GEM. SINCE THIS IS MAJOR
PATTERN CHANGE...FULLY EXPECT THE MDLS TO WAFFLE ON TIMING OF THIS
FROPA...THUS HAVE FOLLOWED THE CONSENSUS MDL SOLUTION WHICH KEEPS
A LOW POP IN THE FCST THRU SUNDAY. A LARGE AREA OF HI PRES IS THEN
FCST TO BUILD INTO THE REGION FOR MON AND BRING COOLER/MUCH DRIER
AIR TO NE WI.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 627 AM CDT TUE AUG 27 2013
MAIN ISSUE IS TIMING AND LOCATION OF THUNDERSTORMS. AFTER MORNING
STORMS EXIT...EXPECT LULL WITH NEW STORMS DEVELOPING FOR THIS
AFTERNOON IN VCNTY OF SFC BOUNDARY EXPECTED TO BE IN AREA BETWEEN
TOMAHAWK AND MARINETTE. BOUNDARY AND STORMS EXPECTED TO MOVE SOUTH
THROUGH REGION BY LATE EVENING. LINGERING MOISTURE AND LIGHT WINDS
TO LEAD TO FOG FORMATION LATE TONIGHT.&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......TE
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
205 PM MST TUE AUG 27 2013
&&
.SYNOPSIS...
THUNDERSTORMS CHANCES WILL BE REDUCING BY SOMEWHAT DRIER AIR WORKING
ITS WAY IN FROM THE EAST THROUGH THE DAY ON WEDNESDAY...WITH JUST
ISOLATED STORMS FORECAST OVER THE LOWER DESERTS OF SOUTH CENTRAL
ARIZONA. AN INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED
BEGINNING WEDNESDAY EVENING...WITH EVEN A BIGGER INCREASE ON
THURSDAY AND FRIDAY AS A WEATHER DISTURBANCE APPROACHES FROM THE
SOUTH. NEAR NORMAL TEMPERATURES ON WEDNESDAY ARE EXPECTED TO FALL TO
BELOW NORMAL VALUES ON THURSDAY AND FRIDAY.
&&
.DISCUSSION...
LATEST VISUAL SATELLITE AND RADAR IMAGERY IS NOW SHOWING ISOLATED
SHOWERS AND THUNDERSTORMS DEVELOPING OVER SOUTHEAST...AND THE HIGHER
ELEVATIONS OF SOUTH-CENTRAL AND NORTHERN ARIZONA. HOWEVER...LATEST
IR IMAGERY CONTINUES TO SHOW DRIER AIR CONTINUING TO TRY TO PITCH
OFF/MIX OUT THE PLUME OF DEEP TROPICAL MOISTURE THAT IS STILL
STRETCHED FROM NORTH TO SOUTH OVER CENTRAL ARIZONA. ALSO...SURFACE
OBS ARE SHOWING SOMEWHAT DRIER AIR IS MOVING INTO SOUTHEAST AND
EAST-CENTRAL ARIZONA...WITH THE DEWPOINT AT TUCSON NOW DOWN TO 52F
FROM THE MID TO UPPER 60S EARLY THIS MORNING. LATEST HRRR MODEL RUN
CONTINUES TO DISSIPATE VIRTUALLY ANY CONVECTIVE ACTIVITY THAT TRIES
TO FORM BEFORE IT CAN MAKE ITS WAY INTO SOUTH-CENTRAL ARIZONA.
THUS...EVEN THOUGH THERE IS CERTAINLY STILL A CHANCE FOR AN ISOLATED
THUNDERSTORM ANYWHERE IN OUR CWA THIS AFTERNOON OR
EVENING...CURRENTLY BELIEVE THAT ANY ACTIVITY THAT DOES DEVELOP WILL
NOT LAST LONG...AND WE WILL CERTAINLY NOT SEE ANYTHING CLOSE TO THE
AMOUNT OF ACTIVITY THAT WE SAW LAST NIGHT
AFTER WHAT WILL BE LIKELY A QUIET MORNING TOMORROW...AN UPRAMPING IN
MONSOON ACTIVITY CONTINUES TO BE IN THE CARDS STARTING TOMORROW
EVENING...AND ESPECIALLY ON THURSDAY AND FRIDAY. LATEST MODEL OUTPUT
CONTINUES TO BRING ANOTHER PLUME OF TROPICAL MOISTURE NORTHWARD INTO
THE REGION AS A STRONG EASTERLY WAVE...THAT IS LIKELY THE REMAINS OF
TROPICAL STORM FERNAND...MOVES NORTHWESTWARD JUST OFF THE WEST COAST
OF MEXICO...EVENTUALLY ENDING OFF THE COAST OF SOUTHERN CA BY EARLY
SATURDAY. THE BIGGEST DIFFERENCES BETWEEN THE MODELS IS THE TIMING
OF THE ARRIVAL OF THE DEEP MOISTURE...WITH THE NAM BEGINNING TO MOVE
IT INTO SOUTHERN ARIZONA BY LATE WEDNESDAY NIGHT...AND THE GFS AND
ECMWF NOT MOVING IT IN UNTIL THURSDAY MORNING. THERE ARE ALSO
DIFFERENCES IN THE AMOUNT OF MOISTURE THAT IS IMPORTED INTO THE
REGION...WITH THE GFS AND NAM PUSHING PWAT VALUES INTO THE 2.00-2.40
INCH RANGE...AND THE ECMWF ONLY PUSHING VALUES INTO THE 1.75-2.00
RANGE. EITHER WAY...IT LOOKS LIKE THAT ANOTHER ROUND OF WIDESPREAD
WETTING RAINS IS LIKELY OVER THE REGION...WITH THE MOISTURE-RICH
ENVIRONMENT LIKELY LEADING TO LOCALLY HEAVY DOWNPOURS AND POSSIBLE
LOCAL FLOODING ISSUES. TEMPERATURES ON THURSDAY AND FRIDAY QUITE
LIKELY WILL BE KEPT IN THE 90S ACROSS THE LOWER DESERTS BY ALL THE
CLOUDS AND RAIN THAT IS EXPECTED OVER THE REGION...WITH PERHAPS SOME
ISOLATED AREAS NOT GETTING OUT OF THE 80S ON AT LEAST ONE OF THE
DAYS.
FORECAST UNCERTAINTY CONTINUES TO BE AN ISSUE OVER THE WEEKEND...AS
ECMWF FORECASTS BEGINNING TO SCOUR OUT SOME MOISTURE WHILE
RETROGRADING RIDGING AND SUBSIDENCE INTO THE REGION...WHILE GFS
FORECASTS MAINTAIN WEAK PERTURBATIONS AND FAVORABLE MOIST VERTICAL
MOTION PROFILES. EITHER SCENARIO APPEARS EQUALLY LIKELY AT THIS
TIME...AND COULD NOT JUSTIFY ADVERTISING A FORECAST TERRIBLY FAR
ABOVE CLIMATOLOGY GIVEN THE OVERALL UNCERTAINTY AND LOWER FORECAST
CONFIDENCE.
&&
.AVIATION...
ALTHOUGH THE ATMOSPHERE OVER THE SOUTHCENTRAL DESERTS WAS WORKED
OVER FAIRLY HEAVILY LAST NIGHT...WITH WIDESPREAD THUNDERSTORM RAINS
COOLING THE BOUNDARY LAYER...MESOANALYSIS GRAPHICS SHOW HIGH CAPE
VALUES DEVELOPING FROM WESTERN MARICOPA COUNTY SOUTH AND EAST INTO
PIMA COUNTY. SUFFICIENT SUNSHINE OVER SERN AZ HAS ALLOWED CONVECTION
TO BEGIN DEVELOPING AGAIN AND STEERING FLOW IS AGAIN FROM THE
SOUTHEAST.
CENTRAL DESERT TAFS DO NOT REFLECT A THUNDERSTORM THREAT AT THIS
TIME...HOWEVER POTENTIAL IS GROWING THAT ISOLATED STORMS MAY DEVELOP
AND MOVE INTO THE AIRFIELDS LATER THIS AFTERNOON...PROBABLY AFTER 4
PM...AND BRING GUSTY WINDS AND HEAVY RAIN ONCE AGAIN. USUALLY IT IS
VERY HARD TO GET TWO CONSECUTIVE ACTIVE WEATHER DAYS IN THE SAME
AREA BUT WE ARE STILL QUITE MOIST AND INSTABILITY IS GROWING. WE
WILL CONTINUE TO MONITOR THE GROWING THREAT...AND WILL UPDATE THE
TAFS TO INCLUDE VCTS OR TEMPO TSRA SHOULD THE CHANCE FOR STORMS
CONTINUE TO INCREASE.
THERE WILL BE INCREASING CHANCES FOR AFTN/EVE THUNDERSTORMS IN THE
CENTRAL DESERTS TOMORROW...AND THEN INTO THE DAY ON THURSDAY AS
TROPICAL MOISTURE FROM FERNAND MOVES INTO THE AREA.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FEW TO SCATTERED MID AND HIGH LEVEL CLOUDS ARE EXPECTED THROUGH THE
TAF PERIOD WITH WINDS LESS THAN 10 KNOTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
TROPICAL MOISTURE FROM FORMER TROPICAL STORM FERNAND WILL SWEEP INTO
THE REGION FROM THE SOUTHEAST ON FRIDAY...LEADING TO A GOOD CHANCE
OF SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAIN. MOISTURE WILL
LINGER THROUGH THE WEEKEND...LEADING TO AN ELEVATED THREAT OF
THUNDERSTORMS...AND THEN THIN SOMEWHAT EARLY NEXT WEEK AS NORMAL
MONSOONAL CONDITIONS WILL PREVAIL. MINIMUM RELATIVE HUMIDITIES WILL
BE VERY HIGH THROUGH THE WEEKEND...MOSTLY GREATER THAN 30 PERCENT
OVER THE DESERTS...AND THEN WILL FALL INTO THE 20S BY MONDAY.
TEMPERATURES WILL REMAIN BELOW SEASONAL NORMALS THROUGH THE FIVE DAY
PERIOD. WINDS WILL BE GENERALLY ON THE LIGHT SIDE EACH DAY FOLLOWING
NORMAL DIURNAL TENDENCIES WITH TYPICAL AFTERNOON GUSTINESS...
ESPECIALLY OVER FAVORED HIGHER TERRAIN LOCATIONS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/MO
AVIATION....CB
FIRE WEATHER...CB
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
1205 PM MST TUE AUG 27 2013
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
OVERALL PRECIPITATION CHANCES WILL DECREASE SLIGHTLY TODAY AND
WEDNESDAY AS DRIER AIR ATTEMPTS TO SETTLE OVER THE REGION FROM THE
EAST....HOWEVER RESIDUAL MOISTURE WILL STILL SUPPORT A FEW STORMS.
A LARGER DISTURBANCE WILL MOVE INTO THE REGION AND REESTABLISH MORE
EXTENSIVE THUNDERSTORM ACTIVITY THURSDAY AND FRIDAY. WITH THE
EXCEPTION OF SOME WARMING TO NEAR AVERAGE LEVELS THE NEXT COUPLE
DAYS...TEMPERATURES WILL GENERALLY REMAIN BELOW THE SEASONAL NORMAL.
&&
.DISCUSSION...
A MUCH QUIETER MORNING ACROSS OUR CWA WHEN COMPARED TO ALL OF
YESTERDAY/S ACTIVITY OVER SOUTH-CENTRAL ARIZONA. THE DISTURBANCE
THAT TRIGGERED THE STORMS YESTERDAY EVENING HAS NOW MOVING RAPIDLY
NORTHWARD INTO UTAH...WITH JUST SOME LEFT-OVER SHOWERS AND A FEW TS
BEING DETECTED ON RADAR OVER THE WESTERN 1/2 OF THE FLAGSTAFF CWA.
BASED ON CURRENT OBSERVATIONS AND RADAR TRENDS...HAVE REDUCED POPS
TO JUST SLIGHT CHANCE ONES OVER LA PAZ AND EXTREME NORTHWEST
MARICOPA COUNTIES FOR THE REMAINDER OF THE MORNING AND EARLY
AFTERNOON HOURS.
GIVEN THE LAST FEW RUNS OF THE HIGH-RES HRRR MODEL...WHICH DID VERY
WELL FORECASTING YESTERDAY/S CONVECTIVE ACTIVITY...AND NOW IS
FORECASTING VERY LITTLE...OR NO CONVECTIVE DEVELOPMENT FOR TODAY AND
TONIGHT...THERE IS NOW EVEN GREATER CONFIDENCE THAT THIS
AFTERNOON/EVENING SHOULD BE A PRETTY QUIET ONE. THUS...HAVE LEFT THE
SHORT-TERM GRIDS FOR THE AFTERNOON/EVENING ALONE...WHICH ARE
FORECASTING JUST A SLIGHT CHANCE FOR STORMS OVER MOST AREAS OF OUR
CWA.
&&
.PREVIOUS DISCUSSION...
EARLY THIS MORNING...AN EASTERLY WAVE WAS PROPAGATING NORTH INTO
SWRN NEW MEXICO WITH THE RIGHT REAR JET DIVERGENCE FIELD LIFTING
INTO NRN ARIZONA. THE PLUME OF DEEP TROPICAL MOISTURE OVER CNTRL/WRN
ARIZONA WAS BECOMING PINCHED BY ADVECTION OF DRIER MID LEVEL AIR
FROM BOTH THE EAST AND WEST PER WV IMAGERY. THIS SCENARIO WAS
ALREADY BEING SEEN IN 00Z/03Z REGIONAL SOUNDING DATA WITH MIXING
RATIOS IN THE H7-H8 LAYER FALLING BELOW 10 G/KG. DESPITE THIS...THE
COMBINATION OF SFC HEATING...MOISTURE ALOFT...AND FAVORABLE ASCENT
SUPPORTED THUNDERSTORM FORMATION ALONG OUTFLOWS AT LOWER ELEVATIONS
THROUGH THE EVENING HOURS.
OPERATIONAL AND HI RES MODELS ONCE AGAIN INDICATE LESSER ACTIVITY
THIS AFTERNOON AND EVENING IN THE WAKE OF THE WAVE PASSAGE AND
GENERAL DRYING TREND THROUGH THE ATMOSPHERIC COLUMN. OF COURSE...THE
SAME 00Z MODELS YESTERDAY FAILED TO CAPTURE THE EXTENT OF ACTIVITY
LAST EVENING...AND IT WASNT UNTIL 12Z INITIALIZATIONS THAT A
SOMEWHAT BETTER OUTCOME WAS ADVERTISED. WITH RESIDUAL MOISTURE LEFT
IN BOTH THE LOWER BOUNDARY LAYER AND MID LEVELS...STILL CANNOT
DISCOUNT ANY PULSING STORM ACTIVITY TODAY...THOUGH MORE ORGANIZED OR
PERSISTENT ACTIVITY SHOULD BE LACKING. OTHERWISE...TEMPERATURES
SHOULD REBOUND TO NEAR AVERAGE LEVELS THIS AFTERNOON...WITH THE
FORECAST TAILORED TOWARDS RAW MODEL CONSENSUS.
OVERALL MOISTURE PROFILES WILL ONLY CHANGE SLIGHTLY WEDNESDAY...WITH
SFC-H7 MIXING RATIOS IN THAT MARGINALLY SUPPORTIVE 10-12 G/KG RANGE.
HOWEVER...BETTER DYNAMICAL ASCENT ON THE LEADING EDGE OF AN EASTERLY
WAVE AND A CORRESPONDING RENEWED PUSH OF DEEPER MOISTURE WILL BEGIN
TO ENTER SERN ARIZONA...HELPING ORGANIZE MORE ROBUST THUNDERSTORM
DEVELOPMENT. BIGGEST QUESTION REMAINS WHETHER THE ATMOSPHERE AT
LOWER ELEVATIONS OF CNTRL ARIZONA WILL ALLOW FOR MORE THAN DECAYING
OUTFLOWS. KEPT RELATIVELY MODEST POPS AWAITING THE MAIN BRUNT OF THE
WAVE AND MOISTURE FLUX BEYOND WEDNESDAY EVENING.
OPERATIONAL MODELS CONTINUE TO SUGGEST A VERY WELL DEFINED
EASTERLY WAVE...PRONOUNCED UPPER DIFLUENCE...AND THICK TROPICAL
MOISTURE PROGRESSING INTO THE FORECAST AREA THURSDAY AND FRIDAY.
PARTIALLY THE REMNANT CIRCULATION OF OLD ATLANTIC TROPICAL CYCLONE
FERNAND COMBINED WITH A SOUTHEAST PACIFIC MOISTURE
TAP...PRECIPITATION MAY COME IN WAVES WITH AN INITIAL BAND OF
ELEVATED LIFT PRECEDING THE WAVE...THEN DIURNAL CONVECTIVELY
GENERATED STORMS. TIMING AND LOCATION UNCERTAINTIES STILL PRECLUDE A
MUCH STRONGER POP MENTION FOR ANY SPECIFIC TIME FRAME...HOWEVER
MODEL SOUNDING FORECASTS OF PROLONGED PERIODS OF PWATS GREATER THAN
2.0 INCHES AND BOUNDARY LAYER MIXING RATIOS AOA 15 G/KG SUGGEST SOME
AMOUNT OF PRECIPITATION WILL BE INEVITABLE SOMETIME DURING THE
THURSDAY/FRIDAY TIME FRAME ACROSS MUCH OF THE CWA.
FORECAST UNCERTAINTY BEGINS TO GROW OVER THE WEEKEND...AS ECMWF
FORECASTS BEGIN TO SCOUR OUT SOME MOISTURE WHILE RETROGRADING
RIDGING AND SUBSIDENCE INTO THE REGION...WHILE GFS FORECASTS
MAINTAIN WEAK PERTURBATIONS AND FAVORABLE MOIST VERTICAL MOTION
PROFILES. EITHER SCENARIO APPEARS EQUALLY LIKELY AT THIS TIME...AND
COULD NOT JUSTIFY ADVERTISING A FORECAST TERRIBLY FAR FROM
CLIMATOLOGY GIVEN THE OVERALL UNCERTAINTY AND LOWER FORECAST
CONFIDENCE.
&&
.AVIATION...
ALTHOUGH THE ATMOSPHERE OVER THE SOUTHCENTRAL DESERTS WAS WORKED
OVER FAIRLY HEAVILY LAST NIGHT...WITH WIDESPREAD THUNDERSTORM RAINS
COOLING THE BOUNDARY LAYER...MESOANALYSIS GRAPHICS SHOW HIGH CAPE
VALUES DEVELOPING FROM WESTERN MARICOPA COUNTY SOUTH AND EAST INTO
PIMA COUNTY. SUFFICIENT SUNSHINE OVER SERN AZ HAS ALLOWED CONVECTION
TO BEGIN DEVELOPING AGAIN AND STEERING FLOW IS AGAIN FROM THE
SOUTHEAST.
CENTRAL DESERT TAFS DO NOT REFLECT A THUNDERSTORM THREAT AT THIS
TIME...HOWEVER POTENTIAL IS GROWING THAT ISOLATED STORMS MAY DEVELOP
AND MOVE INTO THE AIRFIELDS LATER THIS AFTERNOON...PROBABLY AFTER 4
PM...AND BRING GUSTY WINDS AND HEAVY RAIN ONCE AGAIN. USUALLY IT IS
VERY HARD TO GET TWO CONSECUTIVE ACTIVE WEATHER DAYS IN THE SAME
AREA BUT WE ARE STILL QUITE MOIST AND INSTABILITY IS GROWING. WE
WILL CONTINUE TO MONITOR THE GROWING THREAT...AND WILL UPDATE THE
TAFS TO INCLUDE VCTS OR TEMPO TSRA SHOULD THE CHANCE FOR STORMS
CONTINUE TO INCREASE.
THERE WILL BE INCREASING CHANCES FOR AFTN/EVE THUNDERSTORMS IN THE
CENTRAL DESERTS TOMORROW...AND THEN INTO THE DAY ON THURSDAY AS
TROPICAL MOISTURE FROM FERNAND MOVES INTO THE AREA.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FEW TO SCATTERED MID AND HIGH LEVEL CLOUDS ARE EXPECTED THROUGH THE
TAF PERIOD WITH WINDS LESS THAN 10 KNOTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
ANOTHER ACTIVE MONSOON PERIOD IS EXPECTED FROM THURSDAY ONWARD INTO
THE WEEKEND AS DEEP SOUTHERLY FLOW IMPORTS COPIOUS MOISTURE INTO THE
REGION...WITH EMBEDDED WEATHER DISTURBANCES HELPING TO ENHANCE
CONVECTIVE ACTIVITY...WITH A GOOD CHANCE OF WIDESPREAD WETTING RAINS
ACROSS THE ENTIRE DESERT SOUTHWEST. MINIMUM HUMIDITY VALUES ARE
EXPECTED TO ONLY FALL INTO THE 30 TO 40 PERCENT RANGE ACROSS THE
LOWER DESERTS...AND INTO THE 40 TO 55 PERCENT RANGE ACROSS THE
HIGHER ELEVATIONS EACH DAY...WITH EXCELLENT OVERNIGHT RECOVERIES.
THUNDERSTORM ACTIVITY WILL DECREASE SOMEWHAT ON MONDAY AS STRONG
RIDGING BEGINS TO BUILD IN FROM THE EAST. WINDS ARE EXPECTED TO
REMAIN ON THE LIGHT SIDE THROUGH THE PERIOD...EXCEPT NEAR
THUNDERSTORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/MO
AVIATION....CB
FIRE WEATHER...PERCHA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
244 PM CDT TUE AUG 27 2013
.DISCUSSION...
324 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE TODAY`S HEAT...THEN
TEMPS/POPS AS WE TEETER ON THE PERIPHERY OF UNSEASONABLY STRONG LATE
SUMMER UPPER HOT DOME INTO THE WEEKEND.
THE CARCASS OF SUNDAY NIGHT`S MCS PROVIDED A SHROUD OF FAIRLY DENSE
CIRRUS OVER THE AREA MONDAY AFTERNOON HOLDING TEMPS ABOUT 2-4F
COOLER THAN EXPECTED. ONCE AGAIN EARLY THIS MORNING MCS ACTIVITY IS
FESTERING ABOUT TO OUR NORTH ON THE PERIPHERY OF THE UPPER RIDGE.
CONVECTIVELY ENHANCED VORT DRIVING THIS MCS APPEARS TO BE PUSHING
INTO NORTHERN PORTIONS OF LAKE MICHIGAN ALREADY WITH BACK EDGE OF
CIRRUS SHIELD MOVING INTO NW WISCONSIN. HRRR SEEMS TO HAVE A GOOD
HANDLE ON ONGOING CONVECTIVE TRENDS AND IT...ALONG WITH THE MAJORITY
OF THE OTHER GUIDANCE...SUGGESTS THAT TODAY`S CIRRUS DEBRIS WILL
CLEAR OUT BY EARLY AFTERNOON AND ALLOW FOR STRONG HEATING TO TAKE
PLACE...ESPECIALLY NORTHWESTERN CWA. LOW LEVEL THERMAL RIDGE
MOVING INTO THE AREA WITH 925MB TEMPS PROGGED TO RISE TO 26-28C
NORTHWESTERN CWA WHICH WOULD EASILY SUPPORT MIDDLE IF NOT UPPER
90S. IN THE PAST HOUR CONVECTION HAS FLARED OVER NORTHEAST MINNESOTA
WHICH IS CONCERNING AS 850-300MB THICKNESS SUGGESTS THAT COULD SINK
SOUTHWARD AND SPREAD MORE CIRRUS ACROSS THE AREA TODAY.
GIVEN POTENTIAL FOR DEBRIS CLOUDINESS TO LINGER AGAIN TODAY SPLIT
THE DIFFERENCE FOR HIGHS BETWEEN WHAT PROGGED 925MB TEMPS WOULD
SUPPORT AND WHAT CLIMO INFLUENCED MOS NUMBERS FORECAST. ASSUMING
DEWPOINTS DON`T MIX OUT AND ASSUMING CIRRUS CLEARS OUT THEN WE WOULD
GET CLOSE TO THE 105F HEAT INDEX ADVISORY CRITERIA THIS AFTERNOON
NORTH/NORTHWEST AREAS. GIVEN A FORECAST OF CONDITIONS NOT MEETING
CRITERIA AND LOW CONFIDENCE IN THEM EVEN GETTING AS BAD AS I HAVE IN
THE GRIDS...WOULD NOT NORMALLY ISSUE AN ADVISORY...BUT WITH
HEADLINES OUT FOR AREAS NORTH/WEST OF OUR CWA AND POTENTIAL FOR NEAR
RECORD HIGHS DECIDED TO MAKE THE W/W/A MAP PRETTY AND HOIST AN
ADVISORY FOR NORTH CENTRAL ILLINOIS. IF TRENDS THIS MORNING SUGGEST
THAT CIRRUS WONT BE A BIG DEAL THEN DAY SHIFT COULD CONSIDER
EXTENDING THE ADVISORY FARTHER EAST INTO THE CHICAGO AREA.
ANOTHER SHORTWAVE OVER THE EASTERN DAKOTAS THIS MORNING IS PROGGED
TO RIDE THE RIM OF THE RIDGE EAST INTO WISCONSIN THIS AFTERNOON AND
WILL PROBABLY RE-IGNITE THUNDERSTORMS TO OUR NORTH THIS AFTERNOON
WITH THESE STORMS POTENTIALLY CLIPPING OUR NORTHERN AND NORTHEASTERN
CWA THIS EVENING AS THE MOVE SOUTHEASTWARD. MODERATELY STRONG MID
LEVEL FLOW AND FAIRLY STRONG INSTABILITY (ASSUMING TDS DONT MIX OUT)
COULD SUPPORT A LOW END SEVERE THREAT WITH ANY STORMS THAT DO
MEANDER INTO OUR CWA TONIGHT.
LAKE ENHANCED COLD FRONT WILL MOVE INTO THE CWA EARLY WEDNESDAY
MORNING PROGRESSING SOUTHWARD INTO OUR SOUTHERN CWA BY AFTERNOON.
BETTER FORCING ALOFT SHOULD REMAIN TO OUR EAST BUT AM CONCERNED THAT
MOISTURE/INSTABILITY POOLING AND LOW LEVEL CONVERGENCE ALONG THE
FRONT COULD BE ENOUGH TO KICK OFF A THUNDERSTORM WEDNESDAY
AFTERNOON. SLIGHTLY COOLER AIR MASS WILL FILTER IN BEHIND THE
FRONT...WITH COOLING MOST NOTICEABLE NEAR LAKE MICHIGAN. AHEAD OF THE
FRONT WILL BE ANOTHER STEAMY DAY AND WITH BETTER DEWPOINT POOLING
COULD ACTUALLY END UP BEING HOTTER/MORE HUMID IN OUR SOUTHERN CWA
TOMORROW THAN TODAY...BUT THAT WILL HINGE ON THE AMOUNT OF
CLOUDINESS SOMETHING WHICH WILL BE MORE EASILY DIAGNOSED TONIGHT.
LOW LEVEL BAROCLINIC ZONE HANGS UP IN THE NEIGHBORHOOD THROUGH THE
END OF THE WEEK WITH WEAK NORTHWEST FLOW IMPULSES LIKELY TO RIPPLE
AROUND THE PERIPHERY OF THE HEAT DOME MEANS AT LEAST SOME POTENTIAL
FOR THUNDERSTORMS TONIGHT UNTIL STRONG COLD FRONT MOVES THROUGH THIS
WEEKEND. HAVE KEPT FORECAST DRY FOR NOW WEDNESDAY NIGHT THROUGH
THURSDAY BUT NW FLOW`S LIKE THIS ARE NOTORIOUS FOR PRODUCING
"SURPRISES" SO STAY TUNED!
HEADING INTO THE SECOND HALF OF THE LABOR DAY WEEKEND THE DIFFERENCE
BETWEEN THE 27/00Z RUN OF THE ECMWF WHEN COMPARED TO THE 25/12Z RUN
IS ABOUT AS DRAMATIC I`VE EVER SEEN IN THE WARM SEASON. FOR DAYS
MEDIUM RANGE MODELS HAD BEEN ADVERTISING RECORD BREAKING HEAT AND
NOW AFTER STARTING TO TREND SHARPLY COLDER WITH THE 26/12Z RUN THE
LATEST ECMWF NOW FORECASTS NEAR RECORD COLD TEMPERATURES BY MONDAY
WITH H8 TEMPS NEARING 0C! THE REMAINDER OF THE MEDIUM RANGE MODELS
HAVE BEEN TRENDING TOWARD THIS EARLIER FROPA/STRONG COLD PUSH
SOLUTION BUT STILL LAG WELL BEHIND THE UNSEASONABLY COLD ECMWF. IF
ECMWF WERE TO VERIFY WITH THIS INTENSE COOL SNAP THEN OUR FORECAST
WILL LIKELY TAKE A COUPLE MORE CYCLES TO CATCH UP WITH SUCH AN
ABRUPT CHANGE BUT HAVE TRENDED TEMPS DOWN SIGNIFICANTLY FROM THE
INITIALIZED ALLBLEND GUIDANCE...THOUGH IF LATEST EC VERIFIES HIGHS
MONDAY WOULD LIKELY BE IN THE 60S! NEEDLESS TO SAY FORECAST
CONFIDENCE IN THIS TIME PERIOD WILL REMAIN LOW UNTIL WE BEGIN TO SEE
MODELS CONVERGE ON A SOLUTION AND REMAIN MORE STABLE FROM RUN TO RUN.
IZZI
&&
.CLIMATE...
HERE ARE THE RECORD HIGHS FOR TUESDAY...
CHICAGO ROCKFORD
TUESDAY 97 (1973) 97 (1953)
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NO CONCERNS IN THE NEAR TERM.
* SHOWERS/TS POSSIBLE LATE THIS EVENING.
* FROPA LATE TONIGHT WITH WINDS TURNING THE NORTHWEST...AND
EVENTUALLY NORTHEAST EARLY WEDNESDAY MORNING.
* MVFR/IFR CEILINGS POSSIBLE EARLY WEDNESDAY MORNING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
HIGH LEVEL CIRRUS IS THE DOMINANT CLOUD COVER EARLY THIS AFTERNOON
WHILE SOUTHWEST WINDS GUST IN THE UPPER TEENS. THESE CURRENT
PREVAILING CONDITIONS WILL REMAIN THIS AFTERNOON AND FOR A
PORTION OF THE EARLY EVENING AS A TROUGH OF LOW PRESSURE AND
ASSOCIATED FRONTAL BOUNDARY APPROACH FROM THE NORTHWEST. AS THIS
SYSTEM APPROACHES...SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ALONG
AND OUT AHEAD OF IT THIS EVENING. ALTHOUGH...WITH COVERAGE OF
THESE STORMS APPEARING TO BE SPOTTY...HAVE ONLY MADE MENTION OF VC
AT THIS TIME. THIS WILL LIKELY NEED TO BE REFINED AS THE TIME
DRAWS NEAR LATER THIS EVENING. WITH FROPA OVERNIGHT...EXPECT
SOUTHWEST WINDS TO FLOP OVER TO THE NORTHWEST AND THEN NORTH
NORTHEAST WEDNESDAY MORNING...WITH THESE WINDS TO THEN PREVAIL FOR
THE REMAINDER OF THE FORECAST PERIOD. CONTINUE TO MONITOR THE
POTENTIAL FOR LOW CEILINGS EARLY WEDNESDAY MORNING...POSSIBLY MVFR
AND EVEN IFR. THESE LOWER CEILINGS CURRENTLY RESIDE WELL TO THE
NORTH...BUT WILL HAVE THE POTENTIAL TO MOVE SOUTH DOWN THE LAKE
OVERNIGHT. IF THEY DO MAKE IT DOWN TO THE TERMINALS...EXPECT THEM
TO BE MORE TRANSIENT WITH ANY LOWER CEILINGS NOT EXPECTED TO BE
TOO LONG LASTING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE WITH SHOWERS/TS TRENDS LATER THIS EVENING.
* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH POSSIBLE MVFR/IFR CEILINGS EARLY
WEDNESDAY MORNING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR PSBL.
THURSDAY...SCHC SHRA/TSRA OVERNIGHT
FRIDAY AND SATURDAY...CHC SHRA/TSRA.
SUNDAY AND MONDAY...VFR.
JEE
&&
.MARINE...
242 PM CDT
A BROAD TROUGH STRETCHES ACROSS LAKE MICHIGAN THIS AFTERNOON WITH
GENERALLY SOUTHERLY WINDS ACROSS THE LAKE. AS THE TROUGH SAGS
SOUTHEAST OVER THE NEXT 24 HOURS...WINDS WILL TURN NORTHERLY AS HIGH
PRESSURE BUILDS OVER MINNESOTA AND WISCONSIN WITH WINDS PICKING BACK
UP INTO THE 15 TO 20 KT RANGE. WINDS THEN DIMINISH WEDNESDAY NIGHT
AND THURSDAY AS THE HIGH MOVES OVER LAKE MICHIGAN. ANOTHER FRONT
WILL PASS OVER LAKE MICHIGAN ON SUNDAY...WITH THE GRADIENT
TIGHTENING SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS OVER
ONTARIO. WINDS MAY INCREASE FOR A PERIOD INTO THE 30 KT RANGE
MONDAY...THEN DIMINISH MONDAY NIGHT INTO TUESDAY AS THE HIGH
BUILDS SOUTH OVER THE GREAT LAKES.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011 UNTIL 8 PM
TUESDAY.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
113 PM CDT TUE AUG 27 2013
.DISCUSSION...
324 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE TODAY`S HEAT...THEN
TEMPS/POPS AS WE TEETER ON THE PERIPHERY OF UNSEASONABLY STRONG LATE
SUMMER UPPER HOT DOME INTO THE WEEKEND.
THE CARCASS OF SUNDAY NIGHT`S MCS PROVIDED A SHROUD OF FAIRLY DENSE
CIRRUS OVER THE AREA MONDAY AFTERNOON HOLDING TEMPS ABOUT 2-4F
COOLER THAN EXPECTED. ONCE AGAIN EARLY THIS MORNING MCS ACTIVITY IS
FESTERING ABOUT TO OUR NORTH ON THE PERIPHERY OF THE UPPER RIDGE.
CONVECTIVELY ENHANCED VORT DRIVING THIS MCS APPEARS TO BE PUSHING
INTO NORTHERN PORTIONS OF LAKE MICHIGAN ALREADY WITH BACK EDGE OF
CIRRUS SHIELD MOVING INTO NW WISCONSIN. HRRR SEEMS TO HAVE A GOOD
HANDLE ON ONGOING CONVECTIVE TRENDS AND IT...ALONG WITH THE MAJORITY
OF THE OTHER GUIDANCE...SUGGESTS THAT TODAY`S CIRRUS DEBRIS WILL
CLEAR OUT BY EARLY AFTERNOON AND ALLOW FOR STRONG HEATING TO TAKE
PLACE...ESPECIALLY NORTHWESTERN CWA. LOW LEVEL THERMAL RIDGE
MOVING INTO THE AREA WITH 925MB TEMPS PROGGED TO RISE TO 26-28C
NORTHWESTERN CWA WHICH WOULD EASILY SUPPORT MIDDLE IF NOT UPPER
90S. IN THE PAST HOUR CONVECTION HAS FLARED OVER NORTHEAST MINNESOTA
WHICH IS CONCERNING AS 850-300MB THICKNESS SUGGESTS THAT COULD SINK
SOUTHWARD AND SPREAD MORE CIRRUS ACROSS THE AREA TODAY.
GIVEN POTENTIAL FOR DEBRIS CLOUDINESS TO LINGER AGAIN TODAY SPLIT
THE DIFFERENCE FOR HIGHS BETWEEN WHAT PROGGED 925MB TEMPS WOULD
SUPPORT AND WHAT CLIMO INFLUENCED MOS NUMBERS FORECAST. ASSUMING
DEWPOINTS DON`T MIX OUT AND ASSUMING CIRRUS CLEARS OUT THEN WE WOULD
GET CLOSE TO THE 105F HEAT INDEX ADVISORY CRITERIA THIS AFTERNOON
NORTH/NORTHWEST AREAS. GIVEN A FORECAST OF CONDITIONS NOT MEETING
CRITERIA AND LOW CONFIDENCE IN THEM EVEN GETTING AS BAD AS I HAVE IN
THE GRIDS...WOULD NOT NORMALLY ISSUE AN ADVISORY...BUT WITH
HEADLINES OUT FOR AREAS NORTH/WEST OF OUR CWA AND POTENTIAL FOR NEAR
RECORD HIGHS DECIDED TO MAKE THE W/W/A MAP PRETTY AND HOIST AN
ADVISORY FOR NORTH CENTRAL ILLINOIS. IF TRENDS THIS MORNING SUGGEST
THAT CIRRUS WONT BE A BIG DEAL THEN DAY SHIFT COULD CONSIDER
EXTENDING THE ADVISORY FARTHER EAST INTO THE CHICAGO AREA.
ANOTHER SHORTWAVE OVER THE EASTERN DAKOTAS THIS MORNING IS PROGGED
TO RIDE THE RIM OF THE RIDGE EAST INTO WISCONSIN THIS AFTERNOON AND
WILL PROBABLY RE-IGNITE THUNDERSTORMS TO OUR NORTH THIS AFTERNOON
WITH THESE STORMS POTENTIALLY CLIPPING OUR NORTHERN AND NORTHEASTERN
CWA THIS EVENING AS THE MOVE SOUTHEASTWARD. MODERATELY STRONG MID
LEVEL FLOW AND FAIRLY STRONG INSTABILITY (ASSUMING TDS DONT MIX OUT)
COULD SUPPORT A LOW END SEVERE THREAT WITH ANY STORMS THAT DO
MEANDER INTO OUR CWA TONIGHT.
LAKE ENHANCED COLD FRONT WILL MOVE INTO THE CWA EARLY WEDNESDAY
MORNING PROGRESSING SOUTHWARD INTO OUR SOUTHERN CWA BY AFTERNOON.
BETTER FORCING ALOFT SHOULD REMAIN TO OUR EAST BUT AM CONCERNED THAT
MOISTURE/INSTABILITY POOLING AND LOW LEVEL CONVERGENCE ALONG THE
FRONT COULD BE ENOUGH TO KICK OFF A THUNDERSTORM WEDNESDAY
AFTERNOON. SLIGHTLY COOLER AIR MASS WILL FILTER IN BEHIND THE
FRONT...WITH COOLING MOST NOTICEABLE NEAR LAKE MICHIGAN. AHEAD OF THE
FRONT WILL BE ANOTHER STEAMY DAY AND WITH BETTER DEWPOINT POOLING
COULD ACTUALLY END UP BEING HOTTER/MORE HUMID IN OUR SOUTHERN CWA
TOMORROW THAN TODAY...BUT THAT WILL HINGE ON THE AMOUNT OF
CLOUDINESS SOMETHING WHICH WILL BE MORE EASILY DIAGNOSED TONIGHT.
LOW LEVEL BAROCLINIC ZONE HANGS UP IN THE NEIGHBORHOOD THROUGH THE
END OF THE WEEK WITH WEAK NORTHWEST FLOW IMPULSES LIKELY TO RIPPLE
AROUND THE PERIPHERY OF THE HEAT DOME MEANS AT LEAST SOME POTENTIAL
FOR THUNDERSTORMS TONIGHT UNTIL STRONG COLD FRONT MOVES THROUGH THIS
WEEKEND. HAVE KEPT FORECAST DRY FOR NOW WEDNESDAY NIGHT THROUGH
THURSDAY BUT NW FLOW`S LIKE THIS ARE NOTORIOUS FOR PRODUCING
"SURPRISES" SO STAY TUNED!
HEADING INTO THE SECOND HALF OF THE LABOR DAY WEEKEND THE DIFFERENCE
BETWEEN THE 27/00Z RUN OF THE ECMWF WHEN COMPARED TO THE 25/12Z RUN
IS ABOUT AS DRAMATIC I`VE EVER SEEN IN THE WARM SEASON. FOR DAYS
MEDIUM RANGE MODELS HAD BEEN ADVERTISING RECORD BREAKING HEAT AND
NOW AFTER STARTING TO TREND SHARPLY COLDER WITH THE 26/12Z RUN THE
LATEST ECMWF NOW FORECASTS NEAR RECORD COLD TEMPERATURES BY MONDAY
WITH H8 TEMPS NEARING 0C! THE REMAINDER OF THE MEDIUM RANGE MODELS
HAVE BEEN TRENDING TOWARD THIS EARLIER FROPA/STRONG COLD PUSH
SOLUTION BUT STILL LAG WELL BEHIND THE UNSEASONABLY COLD ECMWF. IF
ECMWF WERE TO VERIFY WITH THIS INTENSE COOL SNAP THEN OUR FORECAST
WILL LIKELY TAKE A COUPLE MORE CYCLES TO CATCH UP WITH SUCH AN
ABRUPT CHANGE BUT HAVE TRENDED TEMPS DOWN SIGNIFICANTLY FROM THE
INITIALIZED ALLBLEND GUIDANCE...THOUGH IF LATEST EC VERIFIES HIGHS
MONDAY WOULD LIKELY BE IN THE 60S! NEEDLESS TO SAY FORECAST
CONFIDENCE IN THIS TIME PERIOD WILL REMAIN LOW UNTIL WE BEGIN TO SEE
MODELS CONVERGE ON A SOLUTION AND REMAIN MORE STABLE FROM RUN TO RUN.
IZZI
&&
.CLIMATE...
HERE ARE THE RECORD HIGHS FOR TUESDAY...
CHICAGO ROCKFORD
TUESDAY 97 (1973) 97 (1953)
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NO CONCERNS IN THE NEAR TERM.
* SHOWERS/TS POSSIBLE LATE THIS EVENING.
* FROPA LATE TONIGHT WITH WINDS TURNING THE NORTHWEST...AND
EVENTUALLY NORTHEAST EARLY WEDNESDAY MORNING.
* MVFR/IFR CEILINGS POSSIBLE EARLY WEDNESDAY MORNING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
HIGH LEVEL CIRRUS IS THE DOMINANT CLOUD COVER EARLY THIS AFTERNOON
WHILE SOUTHWEST WINDS GUST IN THE UPPER TEENS. THESE CURRENT
PREVAILING CONDITIONS WILL REMAIN THIS AFTERNOON AND FOR A
PORTION OF THE EARLY EVENING AS A TROUGH OF LOW PRESSURE AND
ASSOCIATED FRONTAL BOUNDARY APPROACH FROM THE NORTHWEST. AS THIS
SYSTEM APPROACHES...SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ALONG
AND OUT AHEAD OF IT THIS EVENING. ALTHOUGH...WITH COVERAGE OF
THESE STORMS APPEARING TO BE SPOTTY...HAVE ONLY MADE MENTION OF VC
AT THIS TIME. THIS WILL LIKELY NEED TO BE REFINED AS THE TIME
DRAWS NEAR LATER THIS EVENING. WITH FROPA OVERNIGHT...EXPECT
SOUTHWEST WINDS TO FLOP OVER TO THE NORTHWEST AND THEN NORTH
NORTHEAST WEDNESDAY MORNING...WITH THESE WINDS TO THEN PREVAIL FOR
THE REMAINDER OF THE FORECAST PERIOD. CONTINUE TO MONITOR THE
POTENTIAL FOR LOW CEILINGS EARLY WEDNESDAY MORNING...POSSIBLY MVFR
AND EVEN IFR. THESE LOWER CEILINGS CURRENTLY RESIDE WELL TO THE
NORTH...BUT WILL HAVE THE POTENTIAL TO MOVE SOUTH DOWN THE LAKE
OVERNIGHT. IF THEY DO MAKE IT DOWN TO THE TERMINALS...EXPECT THEM
TO BE MORE TRANSIENT WITH ANY LOWER CEILINGS NOT EXPECTED TO BE
TOO LONG LASTING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE WITH SHOWERS/TS TRENDS LATER THIS EVENING.
* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH POSSIBLE MVFR/IFR CEILINGS EARLY
WEDNESDAY MORNING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR PSBL.
THURSDAY...SCHC SHRA/TSRA OVERNIGHT
FRIDAY AND SATURDAY...CHC SHRA/TSRA.
SUNDAY AND MONDAY...VFR.
JEE
&&
.MARINE...
225 AM CDT
LOW PRESSURE OVER SOUTH DAKOTA THIS MORNING WILL PASS OVER THE LAKE
TODAY WITH ITS COLD FRONT SLIDING DOWN THE LAKE TONIGHT. AS SUCH
GUSTY SW WINDS ARE ONCE AGAIN EXPECTED OVER THE SOUTHERN HALF OF THE
LAKE TODAY WITH LIGHTER EAST WINDS OVER THE NORTHERN HALF. WINDS
TURN NW TO N BEHIND THE FRONT TONIGHT THEN AS THE HIGH SETTLES IN
OVER THE REGION...WINDS BECOME LIGHT AND VARIABLE. THE HIGH SHIFTS
EAST THURSDAY NIGHT WITH WINDS BECOMING SOUTH ON FRIDAY. LIGHT
WINDS ARE EXPECTED THROUGH THE END OF THIS WEEK...BUT A STRONG LOW
FORMS OVER SASKATCHEWAN FRIDAY NIGHT. GUIDANCE SUGGESTS THE LOW
WILL PASS NORTH OF LAKE MICHIGAN BUT STRONG NW WINDS ARND 30 KT ARE
EXPECTED BEHIND THE LOWS COLD FRONT SUNDAY NIGHT INTO MONDAY
ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011 UNTIL 8 PM
TUESDAY.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1110 AM CDT TUE AUG 27 2013
.DISCUSSION...
324 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE TODAY`S HEAT...THEN
TEMPS/POPS AS WE TEETER ON THE PERIPHERY OF UNSEASONABLY STRONG LATE
SUMMER UPPER HOT DOME INTO THE WEEKEND.
THE CARCASS OF SUNDAY NIGHT`S MCS PROVIDED A SHROUD OF FAIRLY DENSE
CIRRUS OVER THE AREA MONDAY AFTERNOON HOLDING TEMPS ABOUT 2-4F
COOLER THAN EXPECTED. ONCE AGAIN EARLY THIS MORNING MCS ACTIVITY IS
FESTERING ABOUT TO OUR NORTH ON THE PERIPHERY OF THE UPPER RIDGE.
CONVECTIVELY ENHANCED VORT DRIVING THIS MCS APPEARS TO BE PUSHING
INTO NORTHERN PORTIONS OF LAKE MICHIGAN ALREADY WITH BACK EDGE OF
CIRRUS SHIELD MOVING INTO NW WISCONSIN. HRRR SEEMS TO HAVE A GOOD
HANDLE ON ONGOING CONVECTIVE TRENDS AND IT...ALONG WITH THE MAJORITY
OF THE OTHER GUIDANCE...SUGGESTS THAT TODAY`S CIRRUS DEBRIS WILL
CLEAR OUT BY EARLY AFTERNOON AND ALLOW FOR STRONG HEATING TO TAKE
PLACE...ESPECIALLY NORTHWESTERN CWA. LOW LEVEL THERMAL RIDGE
MOVING INTO THE AREA WITH 925MB TEMPS PROGGED TO RISE TO 26-28C
NORTHWESTERN CWA WHICH WOULD EASILY SUPPORT MIDDLE IF NOT UPPER
90S. IN THE PAST HOUR CONVECTION HAS FLARED OVER NORTHEAST MINNESOTA
WHICH IS CONCERNING AS 850-300MB THICKNESS SUGGESTS THAT COULD SINK
SOUTHWARD AND SPREAD MORE CIRRUS ACROSS THE AREA TODAY.
GIVEN POTENTIAL FOR DEBRIS CLOUDINESS TO LINGER AGAIN TODAY SPLIT
THE DIFFERENCE FOR HIGHS BETWEEN WHAT PROGGED 925MB TEMPS WOULD
SUPPORT AND WHAT CLIMO INFLUENCED MOS NUMBERS FORECAST. ASSUMING
DEWPOINTS DON`T MIX OUT AND ASSUMING CIRRUS CLEARS OUT THEN WE WOULD
GET CLOSE TO THE 105F HEAT INDEX ADVISORY CRITERIA THIS AFTERNOON
NORTH/NORTHWEST AREAS. GIVEN A FORECAST OF CONDITIONS NOT MEETING
CRITERIA AND LOW CONFIDENCE IN THEM EVEN GETTING AS BAD AS I HAVE IN
THE GRIDS...WOULD NOT NORMALLY ISSUE AN ADVISORY...BUT WITH
HEADLINES OUT FOR AREAS NORTH/WEST OF OUR CWA AND POTENTIAL FOR NEAR
RECORD HIGHS DECIDED TO MAKE THE W/W/A MAP PRETTY AND HOIST AN
ADVISORY FOR NORTH CENTRAL ILLINOIS. IF TRENDS THIS MORNING SUGGEST
THAT CIRRUS WONT BE A BIG DEAL THEN DAY SHIFT COULD CONSIDER
EXTENDING THE ADVISORY FARTHER EAST INTO THE CHICAGO AREA.
ANOTHER SHORTWAVE OVER THE EASTERN DAKOTAS THIS MORNING IS PROGGED
TO RIDE THE RIM OF THE RIDGE EAST INTO WISCONSIN THIS AFTERNOON AND
WILL PROBABLY RE-IGNITE THUNDERSTORMS TO OUR NORTH THIS AFTERNOON
WITH THESE STORMS POTENTIALLY CLIPPING OUR NORTHERN AND NORTHEASTERN
CWA THIS EVENING AS THE MOVE SOUTHEASTWARD. MODERATELY STRONG MID
LEVEL FLOW AND FAIRLY STRONG INSTABILITY (ASSUMING TDS DONT MIX OUT)
COULD SUPPORT A LOW END SEVERE THREAT WITH ANY STORMS THAT DO
MEANDER INTO OUR CWA TONIGHT.
LAKE ENHANCED COLD FRONT WILL MOVE INTO THE CWA EARLY WEDNESDAY
MORNING PROGRESSING SOUTHWARD INTO OUR SOUTHERN CWA BY AFTERNOON.
BETTER FORCING ALOFT SHOULD REMAIN TO OUR EAST BUT AM CONCERNED THAT
MOISTURE/INSTABILITY POOLING AND LOW LEVEL CONVERGENCE ALONG THE
FRONT COULD BE ENOUGH TO KICK OFF A THUNDERSTORM WEDNESDAY
AFTERNOON. SLIGHTLY COOLER AIR MASS WILL FILTER IN BEHIND THE
FRONT...WITH COOLING MOST NOTICEABLE NEAR LAKE MICHIGAN. AHEAD OF THE
FRONT WILL BE ANOTHER STEAMY DAY AND WITH BETTER DEWPOINT POOLING
COULD ACTUALLY END UP BEING HOTTER/MORE HUMID IN OUR SOUTHERN CWA
TOMORROW THAN TODAY...BUT THAT WILL HINGE ON THE AMOUNT OF
CLOUDINESS SOMETHING WHICH WILL BE MORE EASILY DIAGNOSED TONIGHT.
LOW LEVEL BAROCLINIC ZONE HANGS UP IN THE NEIGHBORHOOD THROUGH THE
END OF THE WEEK WITH WEAK NORTHWEST FLOW IMPULSES LIKELY TO RIPPLE
AROUND THE PERIPHERY OF THE HEAT DOME MEANS AT LEAST SOME POTENTIAL
FOR THUNDERSTORMS TONIGHT UNTIL STRONG COLD FRONT MOVES THROUGH THIS
WEEKEND. HAVE KEPT FORECAST DRY FOR NOW WEDNESDAY NIGHT THROUGH
THURSDAY BUT NW FLOW`S LIKE THIS ARE NOTORIOUS FOR PRODUCING
"SURPRISES" SO STAY TUNED!
HEADING INTO THE SECOND HALF OF THE LABOR DAY WEEKEND THE DIFFERENCE
BETWEEN THE 27/00Z RUN OF THE ECMWF WHEN COMPARED TO THE 25/12Z RUN
IS ABOUT AS DRAMATIC I`VE EVER SEEN IN THE WARM SEASON. FOR DAYS
MEDIUM RANGE MODELS HAD BEEN ADVERTISING RECORD BREAKING HEAT AND
NOW AFTER STARTING TO TREND SHARPLY COLDER WITH THE 26/12Z RUN THE
LATEST ECMWF NOW FORECASTS NEAR RECORD COLD TEMPERATURES BY MONDAY
WITH H8 TEMPS NEARING 0C! THE REMAINDER OF THE MEDIUM RANGE MODELS
HAVE BEEN TRENDING TOWARD THIS EARLIER FROPA/STRONG COLD PUSH
SOLUTION BUT STILL LAG WELL BEHIND THE UNSEASONABLY COLD ECMWF. IF
ECMWF WERE TO VERIFY WITH THIS INTENSE COOL SNAP THEN OUR FORECAST
WILL LIKELY TAKE A COUPLE MORE CYCLES TO CATCH UP WITH SUCH AN
ABRUPT CHANGE BUT HAVE TRENDED TEMPS DOWN SIGNIFICANTLY FROM THE
INITIALIZED ALLBLEND GUIDANCE...THOUGH IF LATEST EC VERIFIES HIGHS
MONDAY WOULD LIKELY BE IN THE 60S! NEEDLESS TO SAY FORECAST
CONFIDENCE IN THIS TIME PERIOD WILL REMAIN LOW UNTIL WE BEGIN TO SEE
MODELS CONVERGE ON A SOLUTION AND REMAIN MORE STABLE FROM RUN TO RUN.
IZZI
&&
.CLIMATE...
HERE ARE THE RECORD HIGHS FOR TUESDAY...
CHICAGO ROCKFORD
TUESDAY 97 (1973) 97 (1953)
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NO CONCERNS IN THE NEAR TERM.
RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS OVER THE SOUTHEAST US WHILE LOW PRESSURE IS OVER
EASTERN SD/SOUTHERN MN. THE LOW PRESSURE WILL TRACK ACROSS MN AND
WI TODAY BEFORE DRIFTING OVER LAKE MICHIGAN AND MI THIS EVENING/TONIGHT.
HIGH LEVEL CLOUD COVER FROM A DYING COMPLEX OVER MI HAS SPREAD
ACROSS THE REGION AND WE MAY GET ANOTHER ROUND OF HIGH LEVEL
CLOUDS FROM A SECOND CONVECTIVE SYSTEM OVER NORTHERN WI.
SW WIND GUSTS WILL ONCE AGAIN INCREASE BY MID MORNING WITH
SLIGHTLY STRONGER SUSTAINED SPEEDS THAN YESTERDAY...ARND 12KT.
GUSTS WILL BE ARND 18KT WITH OCNL GUSTS ARND 20KT ESPECIALLY LATE
THIS AFTN. GUSTS DIMINISH THIS EVENING AS THE LOWS COLD FRONT
APPROACHES FROM THE NORTH. THINKING WINDS WILL BEGIN TO VEER TO
THE NW LATE TONIGHT BECOMING N TO NNE TOMORROW MORNING.
FOR PRECIP...GUIDANCE CONTINUES TO INDICATE ISOL-SCT SHRA/TSRA
WILL DEVELOP TO THE NORTH AND EAST OF THE TERMINALS THIS EVENING
AND OVERNIGHT. THEREFORE KEPT THE TAFS DRY. IF STORMS WERE TO
REACH ANY OF THE TERMINALS...IT NOW LOOKS LIKE GYY WOULD BE THE
BEST BET.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA TRENDS AROUND THE TERMINALS
TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR PSBL.
THURSDAY...SCHC SHRA/TSRA OVERNIGHT
FRIDAY AND SATURDAY...CHC SHRA/TSRA.
SUNDAY AND MONDAY...VFR.
JEE
&&
.MARINE...
225 AM CDT
LOW PRESSURE OVER SOUTH DAKOTA THIS MORNING WILL PASS OVER THE LAKE
TODAY WITH ITS COLD FRONT SLIDING DOWN THE LAKE TONIGHT. AS SUCH
GUSTY SW WINDS ARE ONCE AGAIN EXPECTED OVER THE SOUTHERN HALF OF THE
LAKE TODAY WITH LIGHTER EAST WINDS OVER THE NORTHERN HALF. WINDS
TURN NW TO N BEHIND THE FRONT TONIGHT THEN AS THE HIGH SETTLES IN
OVER THE REGION...WINDS BECOME LIGHT AND VARIABLE. THE HIGH SHIFTS
EAST THURSDAY NIGHT WITH WINDS BECOMING SOUTH ON FRIDAY. LIGHT
WINDS ARE EXPECTED THROUGH THE END OF THIS WEEK...BUT A STRONG LOW
FORMS OVER SASKATCHEWAN FRIDAY NIGHT. GUIDANCE SUGGESTS THE LOW
WILL PASS NORTH OF LAKE MICHIGAN BUT STRONG NW WINDS ARND 30 KT ARE
EXPECTED BEHIND THE LOWS COLD FRONT SUNDAY NIGHT INTO MONDAY
ESPECIALLY OVER THE SOUTHERN HALF OF THE LAKE.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011 UNTIL 8 PM
TUESDAY.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1250 PM CDT TUE AUG 27 2013
.SYNOPSIS...
ISSUED AT 357 AM CDT TUE AUG 27 2013
LARGE...NEARLY STATIONARY UPPER LEVEL HIGH CENTERED OVER EASTERN KS
AND MO AND DOME OF UNSEASONABLY WARM AIR ALOFT CONTINUES TO DOMINATE
THE SYNOPTIC WEATHER PICTURE. TONIGHT/S PRIMARY MCS...ROUNDING THE
TOP OF THE RIDGE WAS EVIDENT ON SATELLITE AND RADAR IMAGERY MOVING
INTO WESTERN LOWER MI...WHILE ADDITIONAL THUNDERSTORMS WERE
DEVELOPING FURTHER UPSTREAM NEAR DLH. AN ASSOCIATED SHIELD OF THIN
CI WAS COVERING MUCH OF EASTERN IA AND NORTHERN IL. AT THE
SURFACE...LOW PRESSURE WAS CENTERED OVER EASTERN SD WITH A SURFACE
COLD FRONT/TROUGH REACHING EAST-NORTHEAST ACROSS CENTRAL MN AND
WI. SURFACE TEMPERATURES WERE IN THE LOWER TO MID 70S WITH
DEWPOINTS IN THE MID 60S TO AROUND 70 OVER THE FORECAST AREA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE AUG 27 2013
FOCUS IS ON POTENTIALLY RECORD BREAKING HEAT TODAY AS THERMAL RIDGE
ALOFT OVERHEAD WILL SUPPORT THE HOTTEST TEMPERATURES SO FAR OF
THE ON-GOING HEAT WAVE. DEEP MIXING AHEAD OF THE APPROACHING
FRONT IN THE NORTHERN PLAINS AND UPPER MS VALLEY WILL TAP INTO THE
THERMAL RIDGE OF 850 TEMPERATURES IN THE RANGE OF 22 TO 23 DEGREES
C. THIS SUPPORTS HIGHS IN THE MID TO UPPER 90S...AND CONTINUES A
TREND OF 1 TO 3 DEGREES DAY TO DAY WARMING TREND SINCE THE
WEEKEND. BASED ON VERIFICATION...WILL CONTINUE TO BUFFER MAXES
ALONG THE MORE MOIST HIGHWAY 20 CORRIDOR DOWN A DEGREE OR TWO. THE
KEY TO HOW HIGH THE HEAT INDEX GETS WILL BE HOW SURFACE DEWPOINTS
RESPOND TO STRONGER WINDS AND DEEP MIXING TODAY. FORECAST MODELS
ARE IN A COUPLE DIFFERENT CAMPS...WITH THE RAP SUGGESTING DRYING
OUT TO THE UPPER 50S TO LOWER 60 BY AFTERNOON...WHILE THE BULK OF
OTHER SHORT TERM MODELS ARE MUCH MORE MOIST WITH SOME SUGGESTING
POOLING OF LOWER TO MID 70S ACROSS THE NORTH. BASED ON
VERIFICATION FROM YESTERDAY HERE AND UPSTREAM IN THE
PLAINS...DEWPOINTS WILL MORE LIKELY RISE A FEW DEGREES EARLY THIS
MORNING...THEN SETTLE IN THE INTO THE MID TO UPPER 60S IN THE
AFTERNOON AS SW WINDS INCREASE TO 10 TO 15 MPH. UNLIKE
YESTERDAY...THE CLOUD SHIELD FROM THE NOCTURNAL CONVECTION SHOULD
BE OUT OF THE REGION BY MID MORNING...YIELDING NEAR FULL SUNSHINE
FOR THE AFTERNOON. HOWEVER...WILL NEED TO WATCH THE NW WI COMPLEX TRENDS
CLOSELY...AS THIS COULD POSSIBLY LEAD TO ANOTHER CI SHIELD IF IT
REMAINS STRONG...FOR LATER THIS MORNING.
HEAT INDEX READINGS THUS ARE EXPECTED TO REACH 100 TO 104 BY EARLY
AFTERNOON OVER MUCH OF THE FORECAST AREA...WITH A GENERAL GRADIENT
FROM LOWER VALUES EAST TO HIGHER WEST AND NW. THE ON-GOING HEAT
ADVISORY WILL THUS REMAIN INTACT...AND IS EXTENDED INTO WED AS
COVERED IN THE LONG TERM AFD SEGMENT.
RECORD TEMPERATURES...AS MENTIONED IN THE CLIMATE SEGMENT
BELOW...APPEAR TO BE MOST AT RISK AT CID AND BRL.
VERY WARM AND HUMID CONDITIONS WILL THEN PREVAIL TONIGHT AS THE
SURFACE COOL FRONT SETTLES SOUTH TO ROUGHLY ALONG THE I-80 CORRIDOR
BY DAWN. ASSOCIATED MOISTURE POOLING AND LIGHT WINDS WILL MAKE FOR
UNCOMFORTABLE CONDITIONS. TEMPERATURES WILL BE IN THE UPPER 70S
TO LOWER 80 FOR MUCH OF THE NIGHT...COOLING TO LOWS AROUND SUNRISE
IN THE LOWER TO MID 70S. THERE IS A LOW POTENTIAL FOR CONVECTION
ALONG THIS BOUNDARY...BUT ANYTHING THAT DEVELOPS WILL LIKELY STAY
WELL EAST OF THE FORECAST AREA...WHERE THE CAP WILL BE WEAKER AND
HAVE KEPT MENTIONABLE POPS OUT OF THE FORECAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CDT TUE AUG 27 2013
FORECAST FOCUS ON HOT AND HUMID WEATHER INTO THE WEEKEND BUT THEN
MUCH COOLER BY LABOR DAY.
WEDNESDAY THROUGH SATURDAY...HAVE EXTENDED THE HEAT ADVISORY FOR
MOST OF THE CWA INTO EARLY WEDNESDAY EVENING. A WEAK BACK DOOR COLD
FRONT WILL PUSH ACROSS THE CWA BUT THE MAIN IMPACT WILL BE TO POOL
HIGHER DEWPOINTS ALONG THE BOUNDARY. MOST OF THE CWA WILL HAVE
AFTERNOON TEMPERATURES IN THE LOWER TO MID 90S WITH DEWPOINTS IN THE
LOWER 70S CREATING HEAT INDEX VALUES OF 100 TO 104. THE EXCEPTION
WILL BE OUR FAR NORTH AND NORTHEAST COUNTIES WHERE TEMPERATURES AND
DEWPOINTS WILL BE SOMEWHAT LOWER BEHIND THE FRONT.
THERE WILL BE A BRIEF BREAK ON THURSDAY WITH NORTHEAST WINDS BEHIND
THE FRONT KEEPING HEAT INDEX VALUES BELOW ADVISORY CRITERIA. HOWEVER
BY FRIDAY THE WEAK FRONT RETURNS AS A WARM FRONT AND LIFTS TO OUR
NORTHEAST BRINGING DEWPOINTS BACK INTO THE LOWER 70S AND HIGHS IN
THE LOWER TO MID 90S. HEAT INDEX VALUES WILL ONCE AGAIN PUSH INTO
THE 100 TO 104 RANGE AND THIS COULD POSSIBLY CONTINUE INTO SATURDAY.
THERE ARE SMALL CHANCES OF THUNDERSTORMS FOR BOTH THURSDAY NIGHT AND
FRIDAY NIGHT...BUT CONFIDENCE IS LOW. THIS IS BASED ON THE
OPERATIONAL MODELS INDICATING RIDGE RIDERS MOVING ACROSS THE UPPER
MIDWEST BUT THE BULK OF THE STORMS SHOULD REMAIN ACROSS MN AND WI.
SUNDAY AND LABOR DAY...THE ECMWF FOR 3 STRAIGHT RUNS HAS SHOWN THE
PLUNGE OF MUCH COOLER TEMPERATURES INTO THE MIDWEST AND GREAT LAKES.
IN FACT...THIS MODEL BRINGS THE 2C 850 MB TEMPERATURE LINE TO NEAR
CHICAGO ON LABOR DAY. CONFIDENCE GROWING THAT THIS IS FOR REAL AS
THE GFS/GEM ARE ALSO ON BOARD WITH THIS DEEPENING TROUGH IN THE
EAST...BUT NOT NEARLY AS COLD AS THE ECMWF. THE STRONG COLD FRONT
SHOULD PUSH INTO THE DVN CWA SOMETIME ON SUNDAY AND THE OPERATIONAL
MODELS SUGGEST THE POTENTIAL FOR AT LEAST ISOLATED TO SCATTERED
THUNDERSTORMS ACCOMPANYING THE FRONT...SUNDAY AFTERNOON OR EVENING.
FOR NOW THE GRIDS ARE DRY BUT LATER SHIFTS WILL NEED TO RE-EVALUATE
THE CHANCES OF THUNDERSTORMS. SURROUNDING OFFICES CONSENSUS WAS TO
LOWER TEMPERATURES ON SUNDAY AND LABOR DAY WITH THE FRONT STRONGER
AND ARRIVING SOONER THAN EARLIER DEPICTED.
AT THIS POINT IN THE GAME LABOR DAY LOOKS VERY PLEASANT WITH
COMFORTABLE HUMIDITY AND MAXIMUM TEMPERATURES IN THE 80S...ACTUALLY
AROUND 80 IN OUR FAR NORTHEAST CWA.
THIS COOLER AIR IS SHORT LIVED AS IT APPEARS THE HEAT AND HUMIDITY
QUICKLY RETURN BY THE MIDDLE OF NEXT WEEK.
HAASE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1246 PM CDT TUE AUG 27 2013
VFR CONDITIONS TO CONTINUE WITH FAIR SKIES...VERY WARM AND HUMID
CONDITIONS. SOUTHWEST WINDS OF 10 TO 20 MPH WILL BECOME LIGHT
WESTERLY TONIGHT. A WEAK BACK DOOR COOL FRONT WILL PASS ACROSS THE
TERMINALS BETWEEN 28/12-18Z...SHIFTING THE WINDS TO THE NORTHEAST
AT 5 TO 10 MPH. SKIES WILL REMAIN FAIR AFTER THE FRONT PASSES.
&&
.CLIMATE...
ISSUED AT 357 AM CDT TUE AUG 27 2013
RECORD HIGHS FOR AUGUST 27...
MOLINE.........97 IN 1976
CEDAR RAPIDS...97 IN 1955
DUBUQUE........94 IN 1895
BURLINGTON.....97 IN 1955
RECORD HIGHS FOR AUGUST 28...
MOLINE.........96 IN 1953
CEDAR RAPIDS...96 IN 1955
DUBUQUE........97 IN 1984
BURLINGTON.....96 IN 1945
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR BUCHANAN-DELAWARE-
DUBUQUE-JACKSON.
HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR BENTON-CEDAR-CLINTON-
DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-
LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR CARROLL-JO
DAVIESS-STEPHENSON.
HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR BUREAU-HANCOCK-
HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-
WARREN-WHITESIDE.
MO...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...HAASE
AVIATION...NICHOLS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1055 AM MDT TUE AUG 27 2013
.SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)
ISSUED AT 222 AM MDT TUE AUG 27 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE SCALE RIDGE STILL
IN PLACE ACROSS THE CENTRAL CONUS. THERE HAS BEEN A GENERAL
WEAKENING OF THE RIDGE CENTER...WITH CURRENT MAX HEIGHT AROUND
595/596DM. A SHORTWAVE TROUGH OVER EASTERN TEXAS SHOWS GOOD
REFLECTION IN BOTH WV AND HEIGHT FIELD AND COULD BE A MINOR FACTOR
IN TEMPS ON WED.
WITH RIDGE WELL ENTRENCHED OVER OUR CWA...THERE WILL BE VERY LITTLE
CHANGE IN THE HOT/DRY CONDITIONS. MODELS SHOW THE SHORTWAVE TROUGH
OVER EASTERN TEXAS ROUNDING SOUTH AND THEN WESTERN EDGE OF THE RIDGE
CENTER THROUGH WED NIGHT. AS HAS BEEN THE CASE THE LAST FEW
DAYS...THERE SHOULD BE GOOD FORCING AND AT LEAST SOME ELEVATED
INSTABILITY WITH THIS FEATURE. MODEL SOUNDINGS STILL SHOW DEEP DRY
AIR MASS IN PLACE...SO OTHER THAN A BRIEF INCREASE IN CLOUDS AND
SLIGHTLY COOLER TEMPS ALOFT I AM NOT ANTICIPATING PRECIP WITH THIS
FEATURE OVER OUR CWA. GENERAL TREND WILL BE A WEAKENING OF THE LEE
TROUGH WITH GRADIENT SHIFTING EASTWARD. THIS SHOULD SUPPORT LESS
WINDY CONDITIONS THROUGH THE REST OF THE FORECAST PERIOD...THOUGH A
FEW GUSTS IN THE 20-30MPH CANT BE RULED OUT THIS AFTERNOON WITH PEAK
MIXING.
REGARDING TEMPS THROUGH THURSDAY...IT LOOKS LIKE A CONTINUATION OF
THE LAST FEW DAYS WITH HIGHS GENERALLY IN THE UPPER 90S/LOW 100S. THE
ONE EXCEPTION WILL BE WED WHEN HIGHS MAY BE ABOUT 5-7F
COOLER...WHICH STILL PUTS HIGHS ACROSS THE CWA IN THE MID-UPPER 90S
FOR MANY LOCATIONS.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 222 AM MDT TUE AUG 27 2013
MEDIUM RANGE MODEL CONSENSUS IS FOR GRADUAL SLIGHT WEAKENING OF THE
UPPER RIDGE EARLY IN EXTENDED PERIOD. A RELATIVELY SIGNIFICANT
SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN PLAINS AND GREAT LAKES
REGION OVER THE WEEKEND ALONG THE NORTHERN EDGE OF THE RIDGE. AN
ASSOCIATED COLD FRONT WILL MOVE SOUTH/SOUTHWESTWARD TOWARD THE AREA.
THE NEW 00Z ECMWF IS STRONGER WITH THIS SHORTWAVE AND PROGRESSES THE
COLD FRONT FURTHER SOUTHWEST INTO OUR AREA LATE SUNDAY INTO MONDAY.
THE GFS IS LESS AGGRESSIVE WITH SOUTH/SOUTHWEST PROGRESSION OF THE
COLD FRONT BUT DOES SHOW AN INCREASE IN DEEP MOISTURE ACROSS THE
AREA SUNDAY AND MONDAY WITH PWAT VALUES SLIGHTLY EXCEEDING
CLIMATOLOGY. THIS IS ENOUGH TO JUSTIFY KEEPING AT LEAST A VERY LOW
POP IN THE NORTHERN PORTION OF THE FORECAST AREA SUNDAY AND MONDAY.
BY LATE MONDAY A MORE HIGHLY AMPLIFIED PATTERN EVOLVES WITH UPPER
RIDGE STRENGTHENING ONCE AGAIN OVER THE PLAINS BETWEEN PACIFIC
NORTHWEST TROUGH AND DEEPENING TROUGH OVER THE EASTERN CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1052 AM MDT TUE AUG 27 2013
VFR CONDITIONS WILL CONTINUE FOR KGLD AND KMCK FOR THE NEXT 24
HOURS AS A RIDGE CONTINUES OVER THE PLAINS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...FS
AREA FORECAST DISCUSSION
NWS JACKSON KY
140 PM EDT TUE AUG 27 2013
.UPDATE...
ISSUED AT 130 PM EDT TUE AUG 27 2013
UPDATED THE FORECAST TO ADD SOME ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TO THE FORECAST FOR TODAY AND TONIGHT. THE NAM BUFR
SOUNDING FOR JKL FOR TODAY WAS SHOWING CAPE ABOVE 2K JOULES AND LOTS
OF INSTABILITY. THE AIRMASS IS PRIMED AND WAITING FOR A TRIGGER. ALSO
MADE SOME CHANGES FOR WEDNESDAY AND WEDNESDAY NIGHT TO BETTER MATCH
UP WITH NEIGHBORING OFFICES. THE REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 652 AM EDT TUE AUG 27 2013
FORECAST IS ON TRACK THIS MORNING...SO NO CHANGES WARRANTED. IT IS
INTERESTING TO NOTE THAT THE LATEST HRRR RUN DOES HINT AT SOME SHOWER
ACTIVITY DRIFTING INTO FAR NORTHEASTERN KENTUCKY THIS EVENING (AFTER
20Z). CONFIDENCE IS STILL WEAK TO INTRODUCE POPS AT THIS TIME...BUT
MAY NEED TO TAKE A CLOSER LOOK AT THE NEED FOR RAIN CHANCES LATER
THIS MORNING IF THE MODELS REMAIN INSISTENT ON BRINGING SOME RAIN
INTO THE AREA.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 257 AM EDT TUE AUG 27 2013
SURFACE/MID/UPPER LEVEL RIDGING WILL CONTINUE TO PROVIDE ANOTHER
QUIET WEATHER DAY ACROSS EASTERN KENTUCKY TODAY. THERE IS A MCS
DROPPING SOUTHEAST ACROSS NORTHERN LAKE MICHIGAN THIS MORNING. THIS
SYSTEM WILL LIKELY WEAKEN AND DISSIPATE AFTER SUNRISE...BUT
SHOWERS/STORMS COULD REDEVELOP ASSOCIATED WITH THE MCV THIS AFTERNOON
INTO THIS EVENING. FORTUNATELY...THE TRAJECTORY SHOULD KEEP THIS
COMPLEX TO OUR NORTHEAST...ALLOWING US TO ENJOY ANOTHER PRECIPITATION
FREE DAY AS OUR AREA REMAINS CAPPED. THE QUIET CONDITIONS WILL
PERSIST INTO TONIGHT WITH MORE VALLEY FOG ANTICIPATED AS DEW POINTS
CONTINUE TO CREEP UPWARDS. A SHORTWAVE TROUGH WILL DROP SOUTHEAST AS
THE RIDGE BREAKS DOWN ON WEDNESDAY. THE TIMING REMAINS IN QUESTION
WITH THIS SYSTEM...BUT OPTING TO GO WITH A COMPROMISE WHICH WOULD
BRING THE SYSTEM INTO EASTERN KENTUCKY LATE IN THE DAY. THIS SHOULD
ALLOW FOR MAINLY A DRY DAY FOR WEDNESDAY WITH THE THREAT OF RAIN
ARRIVING LATE. THERE IS SOME WIND SHEAR PRESENT WEDNESDAY EVENING AND
WITH MODEST INSTABILITY...WE COULD SEE A MARGINAL THREAT FOR
STRONG/DAMAGING WINDS AS SHOWERS AND STORMS PUSH SOUTH/SOUTHEAST.
WILL CONTINUE TO CUT 5 TO 6 DEGREES OFF OF MOS GUIDANCE AS IT HAS
REMAINED MUCH TOO WARM OVER THE PAST SEVERAL DAYS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 455 AM EDT TUE AUG 27 2013
A COLD FRONT WITH A WEAK LOW PRESSURE WAVE ALONG IT WILL DROP SOUTH
THROUGH THE AREA WEDNESDAY NIGHT AND THURSDAY MORNING UNDER NW FLOW
ALOFT. THE OCCURRENCE OF PRECIP REMAINS PROBLEMATIC...WITH CONVECTION
NEEDING TO OVERCOME FAIRLY WARM MID LEVEL TEMPS. IT IS MOST LIKELY
FURTHER TO OUR EAST WITH LIFT BEING AIDED ALONG A WARM FRONT. WILL
CARRY 20-40 PERCENT POPS LOCALLY. PRECIP COULD LINGER INTO THURSDAY
MORNING AS THE FRONTS EXITS TO THE SOUTH. THE EXTENT OF DRYING BEHIND
THE FRONT NOW LOOKS TO BE MUCH MORE IN QUESTION...WITH MODEL RUNS
FROM MONDAY NIGHT ONLY INDICATING MODEST DRYING. IT SHOULD BE ENOUGH
TO RESULT IN DRY WEATHER FROM LATE THURSDAY THROUGH FRIDAY NIGHT.
HOWEVER...THE THREAT OF SHOWERS AND STORMS RETURNS ALREADY ON
SATURDAY AS A STRONG UPPER RIDGE CENTERED TO OUR WEST WEAKENS AND
MID LEVELS COOL SLIGHTLY...AND OUR LOW LEVEL FLOW BEGINS TO PICK UP
FROM THE S AND SW AND BRINGS SLIGHTLY MORE MOIST LOW LEVEL AIR BACK
INTO THE AREA. HAVE USED SLIGHT CHANCE POPS ON SATURDAY AND AGAIN
SUNDAY INTO SUNDAY NIGHT. THE WARM/MOIST ADVECTION PERSISTS INTO
MONDAY...WHEN ANOTHER COLD FRONT APPROACHES FROM THE NW. HAVE USED A
LOW CHANCE POP WITH THE APPROACH OF THE FRONT ON MONDAY. TEMPS WILL
BE VERY WARM THROUGH THE PERIOD...BUT BASED ON A MODEL BLEND...HAVE
UNDERCUT GFS MEXMOS A BIT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 130 PM EDT TUE AUG 27 2013
VFR CONDITIONS SHOULD PERSIST THROUGH THE REMAINDER OF THE DAY AND
INTO TONIGHT. THERE MAY BE SOME TEMPO MVFR VICINITY OF THE STRONGER
SHOWERS AND THUNDERSTORMS. SOME SHOWERS ARE ALREADY POPPING UP IN
FLOYD AND PIKE COUNTIES THIS AFTERNOON. THEY SHOULD BE ISOLATED TO
SCATTERED. THERE IS LOTS OF POTENTIAL ENERGY IN THESE STORMS...SO
THERE COULD BE SOME STRONGER THAN NORMAL LLWS WITH THESE
THUNDERSTORMS. GOING WITH PERSISTENCE FOR THE FOG TONIGHT. THERE
SHOULD ONLY BE MVFR FOR A SHORT TIME IN THE MORNING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
431 PM EDT TUE AUG 27 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 428 PM EDT TUE AUG 27 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW FLOW THROUGH THE NRN GREAT
LAKES ATOP A MID/UPPER LEVEL RIDGE CENTERED OVER MO/KS/AR. NO
SHORTWAVE TROUGHS WERE NOTED UPSTREAM THAT ARE LIKELY TO HAVE A
SIGNIFICANT AFFECT ON UPPER MICHIGAN. AT THE SFC...A WEAK
TROUGH/FRONT EXTENDED FROM NEAR MNM TO MSP WITH WEAK HIGH PRES TO
THE NW OF LAKE SUPERIOR BRINGING LIGHT NE LOW LEVEL FLOW ACROSS LAKE
SUPERIOR. PERSISTENT LOW CLOUDS OVER THE SRN HLF OF THE CWA...HAVE LIMITED
TEMPS AND RESULTANT INSTABILITY DESPITE DEWPOINTS REMAINING AROUND
70. THE LAKE BREEZE FRONT INTO NRN UPPER MI HAS PRODUCED MAINLY JUST
TCU WITH ONLY A FEW SPRINKLES. WHILE THE TSRA ALONG THE 900-700 MB
FGEN ZONE THROUGH S CNTRL UPPER MI HAD MOVED INTO NRN LAKE
MI...ADDITIONAL TSRA WERE DEVELOPING IN NE WI JUST TO THE NORTH OF
THE FRONT WHERE MLCAPE VALUES HAD CLIMBED INTO THE 2K-3K J/KG RANGE.
EXPECT MAINLY JUST ISOLD SHRA AND POSSIBLY A TSRA OVER CNTRL UPPER
MI ALONG THE LAKE BREEZE BOUNDARY LATE THIS AFTERNOON AND EVENING
WHERE INSTABILITY WAS MORE MODEST...ONLY TO NEAR 500-1000 J/KG. THE
STRONGER TSRA ALONG THE FRONT MAY JUST BRUSH THE FAR SRN CWA NEAR
MNM EARLY BUT SHOULD SAG SOUTH OF THE AREA BY 21Z-22Z. ADDITIONAL
ELEVATED SHRA/TSRA NEAR ESC LATE THIS AFTERNOON IN THE AREA OF
WAA/ISENTROPIC LIFT SHOULD ALSO MOVE OFF TO THE SE BY THIS EVENING.
LARGER SCALE SUBSIDENCE WILL THEN TAKE OVER TONIGHT AS WEAK TO
MODERATE 700-300 MB QVECTOR DIV AND SFC HIGH PRES BUILDS OVER THE
AREA. WITH THE LIGHT WINDS AND ABUNDANT LOW LEVEL MOISTURE...AREAS
OF FOG/STRATUS ARE EXPECTED TO DEVELOP. WITH ONLY WEAK DRY ADVECTION
AND DEWPOINTS ONLY DROPPING INTO THE LOWER TO MID 60S...MIN TEMPS
WILL REMAIN WELL ABOVE NORMAL. THE NNE LOW LEVEL FLOW TONIGHT INTO
EARLY WED COULD ALSO BRING FOG/STRATUS INTO LOCATIONS ALONG LAKE
SUPERIOR. AFTER DAYTIME HEATING BURNS OFF ANY LINGERING LOW
CLOUDS...SUNSHINE SHOULD PUSH INLAND TEMPS INTO THE LOWER TO MID 80S
WITH LOWER READINGS IN THE MID TO UPPER 70S ALONG LAKE SUPERIOR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 428 PM EDT TUE AUG 27 2013
SFC HIGH OVERHEAD WEDNESDAY NIGHT SLOWLY SINKING SE THROUGH
FRIDAY...AS A WEAK FRONTAL TROUGH LINGERS ACROSS CENTRAL AND S
ONTARIO. WEDNESDAY NIGHT INTO THURSDAY MORNING STILL LOOK DRY...OUT
AHEAD OF THE NEXT SHORTWAVE OVER S ONTARIO ROUNDING THE SIGNIFICANT
RIDGE DOMINATING MUCH OF THE CENTRAL U.S. IT STILL LOOKS LIKE THE
BEST CHANCE FOR CONVECTION AND MODERATE RAIN WILL BE ALONG AND S OF
THE WI BORDER THURSDAY NIGHT.
LARGE HIGH PRESSURE OVER CENTRAL CANADA WILL SHIFT ACROSS N
ONTARIO ON FRIDAY...LEAVING UPPER MI IN BETWEEN -2 TO -6C AIR OVER S
HUDSON BAY HOTTER 22-25C TEMPERATURES OVER THE CENTRAL PLAINS. WITH
A SERIES OF WEAKER DISTURBANCES SWINGING IN FROM THE NW IT WILL BE
DIFFICULT TO KEEP THE MENTION OF SHOWERS AND THUNDERSTORMS OUT OF
THE FCST FOR FRIDAY AND FRIDAY NIGHT...ALTHOUGH THE LATEST MODEL
GUIDANCE DOES SUGGEST THAT IT COULD BE TRIMMED BACK A BIT MORE THAN
MY LAST MINUTE 20Z UPDATE.
THE SFC LOW CENTERED OVER THE PLAINS WILL SINK TO OUR S ON SATURDAY.
THIS WILL RESTRICT MUCH OF THE HOTTER AIR FROM PUSH ACROSS THE UPPER
GREAT LAKES. THE MAIN STORY WILL BE THE DEEPENING SFC LOW OVER LAKE
WINNIPEG FRIDAY NIGHT/SATURDAY MORNING MOVING ACROSS CENTRAL AND S
ONTARIO SATURDAY NIGHT /BOTTOMING OUT PRESSURE WISE AROUND 997MB/.
THE COLD FRONT IS EXPECTED TO DRAG ACROSS W AND CENTRAL UPPER MI
OVERNIGHT...AND EXIT E UPPER MI SUNDAY MORNING.
THE 27/00Z ECMWF LOOKS TO BE QUICKER AND DEEPER STILL WITH THE
TIMING OF THE 500MB TROUGH SWINGING ACROSS S CENTRAL CANADA AND
SUPPRESSING THE DOMINANT RIDGE TO THE 4-CORNERS REGION...AND IS A
SIGNIFICANT OUTLIER COMPARED TO THE GFS ENSEMBLE MEMBERS. WITH THE
TROUGH FORMING A FULL-FLEDGED LOW OVER SE CANADA MONDAY/MONDAY
NIGHT...UPPER MI WILL BE ABLE TO GET SOME RELIEF FROM THE HEAT.
SINGLE DIGIT 850MB TEMPS WILL SLIDE IN SUNDAY NIGHT...WITH BOTH 12Z
RUNS OF THE ECMWF AND GFS SHOWING 4C MONDAY MORNING.
THE COOLER TEMPERATURES WILL BE SHORT LIVED AS THE HIGH AMPLITUDE
500MB RIDGE OVER THE SOUTHERN STATES EXTENDS ACROSS THE ROCKIES ON
MONDAY...AND PUSHES ACROSS THE N PLAINS/S CENTRAL CANADA AND EDGES
ACROSS THE UPPER GREAT LAKES ON TUESDAY. LOOK FOR 70S AND POSSIBLY
80S TO RETURN AGAIN BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 137 PM EDT TUE AUG 27 2013
DAYTIME HEATING HAS HELPED LIFT CIGS INTO THE MVFR RANGE.
ONCE WINDS BECOME MORE NORTHERLY LATER TODAY...EXPECT LOWER MVFR
CLOUDS TO LOWER TO IFR WITH ADDITIONAL MOISTURE OFF LK SUPERIOR
UPSLOPING INTO KIWD. CONDITIONS MAY LOWER FURTHER THERE TONIGHT.
AS WINDS TURN OFF LK SUPERIOR AT KSAW TONIGHT...CONDITIONS ARE ALSO
EXPECTED TO LOWER TO IFR AT SAW WITH MOIST UPSLOPE FLOW. ENOUGH LOW
LEVEL MOISTURE IS EXPECTED TO LINGER AT CMX WITH LIGHT WINDS AND SOME
RADIATIONAL COOLING FOR CONDITIONS TO DROP BACK INTO THE VLIFR RANGE
TONIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT TUE AUG 27 2013
LIMITED PRESSURE GRADIENTS ACROSS LAKE SUPERIOR SHOULD KEEP WINDS
BELOW 20KTS THROUGH THE FORECAST PERIOD. AREAS OF FOG WILL PERSIST
ACROSS MUCH OF LAKE SUPERIOR WITH HIGH DEWPOINTS OVER THE REGION.
AS WINDS TURN TO THE NORTH TONIGHT...EXPECT THE FOG TO PUSH SOUTH
THROUGH WEDNESDAY MORNING AND THEN DIMINISH SOME AS SLIGHTLY DRIER
CANADIAN AIR MOVES SOUTH OVER THE LAKE THROUGH WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
358 PM EDT TUE AUG 27 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 358 PM EDT TUE AUG 27 2013
AN AREA OF THUNDERSTORMS WILL PRECEDE THE COLD FRONT EARLY
TONIGHT. SOME STORMS MAY HAVE DAMAGING WINDS AND LARGE HAIL FROM
THESE STORMS. ALSO VERY HEAVY RAINFALL IS POSSIBLE AS THE LINE OF
STORMS MOVES THROUGH THE AREA.
A LARGE CANADIAN HIGH MOVES ACROSS THE AREA WEDNESDAY INTO
THURSDAY BEFORE ANOTHER FRONTAL WAVE MOVES THROUGH THE AREA FRIDAY
WITH A CHANCE OF SCATTERED THUNDERSTORMS. TEMPERATURES WILL
CONTINUE TO BE WARMER THAN NORMAL THROUGH SUNDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 358 PM EDT TUE AUG 27 2013
THE MAIN ISSUE WITH THIS FORECAST IS THE RISK OF STRONG TO SEVERE
STORMS EARLY THIS EVENING AND ALSO THE POTENTIAL FOR FLOODING AS
THE ATMOSPHERE IS VERY MOIST AHEAD OF THE COLD FRONT.
THE COMBINATION OF SHORTWAVE... AN 80 KNOT SPEED MAX ON THE POLAR
JET DIVING SOUTHEAST ACROSS LAKE HURON...AN ASSOCIATED 30 KNOT
LOW LEVEL JET NEAR AND SOUTH OF INTERSTATE 96 FEEDING INTO THE
ASSOCIATED FRONTAL WAVE DIVING SOUTHEAST FROM EASTERN MINNESOTA
WILL FEED ON THE 250O J/KG OF MIXED LAYER CAPE OVER SOUTHERN AND
CENTRAL LOWER MICHIGAN THIS EVENING TO BRING THE POTENTIAL FOR
STRONG TO SEVERE STORMS THIS EVENING OVER MOST OF SOUTHWEST LOWER
MICHIGAN. THERE IS A DIFFERENTIAL HEATING BOUNDARY NEAR ROUTE
10...SOUTH OF WHICH ANY STORMS WOULD BE SURFACE BASED THIS
EVENING. AS THE LINE OF STORMS OVER NORTHWEST LOWER MICHIGAN MOVES
SOUTH OF ROUTE 10 I WOULD EXPECT THE STORMS TO INTENSIFY. WHILE
THE SURFACE WINDS ARE NOT ALL THAT STRONG INTO THE FRONT... THERE
IS A DRY LAYER OF AIR BELOW 800 MB...SEEN ON BOTH THE RAP AND NAM
SOUNDINGS THAT WOULD SUPPORT VERY STRONG WINDS FROM THESE STORMS.
ALSO THERE IS THE THREAT FOR LOCALIZED FLOODING AS PRECIPITABLE
WATER VALUES ARE OVER 2 INCHES WHICH IS MORE THAN 2 STANDARD
DEVIATIONS FROM NORMAL. SO EVEN THROUGH THE STORMS WILL BE MOVING
AROUND 35 TO 40 KNOTS...THE RAIN MAY BE HEAVY ENOUGH TO CAUSE
FLOODING IN URBAN AREA OR AREAS WITH POOR DRAINAGE. ALSO MOST OF
OUR NORTHERN CWA HAD OVER A HALF INCH OF RAIN LAST NIGHT...SOME
AREAS HAD OVER 1 1/2 INCHES SO THE SOIL IS RATHER WET THERE
ALREADY.
ONCE THE STORMS MOVE THROUGH LATER THIS EVENING DRIER AIR MOVES IN
BEHIND THE FRONT BUT THERE IS SOME LOW LEVEL MOISTURE THAT WRAPS
AROUND THE SYSTEM SO EVEN THROUGH THE STORMS SHOULD END... THE
REAL CLEARING OF THE SKY MY TAKE UNTIL MID DAY WEDNESDAY.
HIGH PRESSURE WILL BRING MOSTLY CLEAR SKIES AND LOWER DEW POINTS
WEDNESDAY NIGHT INTO THURSDAY. ANOTHER FRONTAL WAVE MAY BRING MORE
THUNDERSTORMS TO THE AREA LATER THURSDAY NIGHT.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 358 PM EDT TUE AUG 27 2013
UNSEASONABLY WARM AND HUMID CONDITIONS ARE ANTICIPATED FRIDAY AND
SATURDAY. THERE IS A SMALL CHC OF A SHOWER OR STORM FRIDAY AS A WEAK
SHORTWAVE MAY MOVE IN FROM THE WNW AND COMBINE WITH WEAK INSTABILITY
TO CAUSE DEVELOPMENT OF A SHOWER OR TWO.
A BETTER CHANCE FOR SHOWERS AND STORMS SHOULD COME SATURDAY THROUGH
SATURDAY NIGHT ALONG AND OUT AHEAD OF THE APPROACHING COLD FRONT. NW
FLOW CAA WILL COMMENCE BEHIND THE FRONT ON SUNDAY BUT MAX TEMPS
SUNDAY SHOULD STILL REACH THE UPPER 70S TO LOWER 80S. HOWEVER BY
LABOR DAY AND FOR TUESDAY IT WILL BE MUCH COOLER WITH MAX TEMPS
LIKELY STRUGGLING TO REACH THE LOWER 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY)
ISSUED AT 1255 PM EDT TUE AUG 27 2013
VFR CONDITIONS ARE ANTICIPATED AT ALL THE TERMINALS THIS AFTERNOON.
THUNDERSTORMS ARE EXPECTED TO DEVELOP FROM NORTH TO SOUTH DURING THE
EARLY TO MID EVENING HOURS TONIGHT... MOST LIKELY IMPACTING KMKG TOWARD
22Z... KGRR AND KLAN BY AROUND 00Z AND THE TERMINALS ALONG THE I-94
CORRIDOR BY 01Z-02Z. THESE STORMS MAY CONTAIN GUSTY WINDS...
FREQUENT LIGHTNING AND VERY HEAVY DOWNPOURS.
THE STORMS WILL MOVE OUT LATE THIS EVENING BUT SHOWERS WILL LINGER
OVERNIGHT ALONG WITH DEVELOPMENT OF SOME LOW CLOUDS AND FOG THAT
WILL CAUSE CONDITIONS TO DETERIORATE TO MVFR THEN IFR. CONDITIONS
WILL IMPROVE SLOWLY FROM IFR TO MVFR DURING THE MID TO LATE MORNING
HOURS WEDNESDAY.
&&
.MARINE...
ISSUED AT 358 PM EDT TUE AUG 27 2013
WINDS SHOULD BECOME NORTH AND BE ON THE LIGHT SIDE BEHIND THE
COLD FRONT WEDNESDAY INTO THURSDAY SO I DO NOT SEE MUCH OF AN
ISSUE WITH HAVING TO HAVE A SMALL CRAFT ADVISORY AT THIS POINT.
&&
.HYDROLOGY...
ISSUED AT 358 PM EDT TUE AUG 27 2013
GIVEN THE HIGH PRECIPITABLE WATER VALUES IN THE ATMOSPHERE AHEAD
OF THE COLD FRONT THERE IS THE POTENTIAL FOR FLOODING OF AREAS
WITH POOR DRAINAGE. SOME LOCALIZED AREAS COULD SEE OVER AN INCH OF
RAIN IN LESS THAN AN HOUR WITH THE STRONGER STORMS... THAT SORT OF
RAINFALL RATE WOULD BE A PROBLEM IN URBAN AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
129 PM EDT TUE AUG 27 2013
.AVIATION...
//DISCUSSION...
CONVECTION STILL ONGOING OVER NORTHERN LOWER MICHIGAN AND CONTINUES
TO SLOWLY MOVE TO THE SOUTHEAST AS IT DIMINISHES. MBS STANDS THE
BEST CHANCE AT SEEING PRECIPITATION THIS AFTERNOON AND HAVE INCLUDED
THAT IN THE TAF. EXPECTING STORMS TO RE-FIRE AFTER 00Z AS AREAS OF
VORTICITY CONTINUE TO SLIDE DOWN OVER THE UPPER LEVEL RIDGE AND THE
LOW LEVEL JET GETS GOING THIS EVENING...AS WHAT HAS BEEN SEEN THE
PAST FEW DAYS. TIMING OF STORMS STILL LOOKING TO BE IN THE 03Z TO
06Z TIMEFRAME FOR DTW/YIP/DET...WITH SCATTERED SHOWERS OVERNIGHT.
MAIN THREATS WITH STORMS WILL BE WINDS AND HEAVY RAIN. MAIN
CHALLENGE WITH RESPECT TO SEVERE WEATHER REMAINS ON WHETHER THE
CLOUDS CAN THIN ENOUGH TO ALLOW FOR INCREASED INSTABILITY ACROSS THE
AREA.
FOR DTW...SHOWERS AND STORMS FROM UPSTREAM MCS EXPECTED TO CONTINUE
TO DIMINISH AS IT MOVES TO THE SOUTHEAST. THERE IS SLIGHT POTENTIAL
FOR SOME OF THE SHOWERS TO HOLD TOGETHER...HOWEVER CONFIDENCE IS TOO
LOW AT THIS POINT TO MENTION IN THE TAFS FOR THE AFTERNOON AND WILL
CONTINUE TO MONITOR TRENDS. CLOUDS WILL REMAIN WITH CONVECTION
EXPECTED TO REDEVELOP AROUND 03Z.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN THUNDERSTORM POTENTIAL AFTER 00Z.
* MEDIUM CONFIDENCE IN CEILINGS FALLING BELOW 5000 FT WEDNESDAY
MORNING.
&&
.PREV DISCUSSION...ISSUED 1124 AM EDT TUE AUG 27 2013
UPDATE...
MORNING CONVECTION HAS SINCE MOVED OFF TO THE SOUTHEAST...LEAVING
SE MI INBETWEEN TWO AREAS OF CONVECTION. THE AREA OF CONCERN FOR
THIS AFTERNOON IS THE ONGOING CONVECTION CURRENTLY MOVING OVER
NORTHERN LOWER MICHIGAN. PRECIP FROM THE UPSTREAM MCS HAS BEEN
DIMINISHING AS IT MOVES INTO DRIER AIR AS SEEN ON THE 12Z APX
SOUNDING. LATEST HRRR RUN CONTINUES TO ADVERTISE THE PROGRESSION
OF CONVECTION ACROSS SE MI...WITH REDEVELOPMENT OF STORMS AFTER
00Z. LATEST MESOANALYSIS AND SATELLITE DOES SHOW MORE MODEST CAPE
VALUES OVER WESTERN PORTIONS OF MICHIGAN WHERE CLOUDS HAVE BEEN
ABLE TO BREAK. THE BETTER CHANCE FOR SEVERE WEATHER IS STILL
EXPECTED TO BE AFTER 00Z...HOWEVER THIS WILL BE DEPENDENT ON HOW
CURRENT SHOWERS HOLD TOGETHER THROUGH THE EARLY AFTERNOON AND
AMOUNT OF INSTABILITY THAT BUILDS ACROSS THE AREA THIS EVENING. STILL
LOOKING AT MAIN THREATS WITH ANY STORMS BEING WINDS AND HEAVY
RAIN.
PREV DISCUSSION...ISSUED 347 AM EDT TUE AUG 27 2013
SHORT TERM... TODAY AND TONIGHT
LARGER SCALE ENVIRONMENT REMAINS VIRTUALLY A CARBON COPY OF THAT
NOTED 24 HOURS AGO...SE MICHIGAN RESIDING ALONG THE NORTHEAST FLANK
OF STRONG UPPER RIDGING ANCHORED OVER THE CENTRAL PLAINS.
WELL-DEFINED THETA-E/MOISTURE AXIS EMANATING SOUTHEAST OF THE MAIN
MOISTURE PLUME SITUATED OVER THE UPPER MS VALLEY NOW DRAPED ACROSS
FAR SOUTHEAST MICHIGAN. EARLY DAY FOCUS TARGETS THE INBOUND
CONVECTIVE COMPLEX CURRENTLY WORKING ACROSS NORTHERN LAKE MICHIGAN.
RECENT RADAR/SATELLITE TRENDS AND HI RES MODEL GUIDANCE SUGGEST SOME
FORM OF THIS COMPLEX WILL WORK ACROSS SE MICHIGAN THIS MORNING
/MAINLY M-59 NORTHWARD/. WHILE THE ARRAY OF MODEL GUIDANCE PROVIDE
A MIXED SIGNAL ON THE RESPONSE...THERE IS A MORE CONCERTED EXPANSION
NOTED AS THE ASSOCIATED MID LEVEL WAVE WORKS ACROSS THE EXISTING
HIGHER THETA-E PLUME. THE MORNING TIMING IS CERTAINLY NOT
IDEAL...BUT RECENT SPC MESOANALYSIS DOES REVEAL ROUGHLY 1000 J/KG OF
EXISTING MUCAPE ALONG AND SOUTHWEST OF A TRI-CITIES TO MOUNT CLEMENS
LINE. THIS WILL SUPPORT A HIGHER END POP /ESPECIALLY NORTH/...WITH
A SMALL WINDOW FOR A FEW STRONGER CELLS TO EMERGE BEFORE THE ENTIRE
COMPLEX EXITS TO THE SOUTHEAST BY LATE MORNING.
BRIEF PERIOD OF SUBSIDENCE AND SOME LAGGING RESIDENCE TIME TO THE
ASSOCIATED CIRRUS CANOPY WILL CONTAIN THE DEGREE OF DESTABILIZATION
FOR A PERIOD OF TIME INTO MIDDAY. HOWEVER...RENEWED THETA-E/WARM
AIR ADVECTION WILL COMMENCE IN THE WAKE OF THIS WAVE AS SOUTHWEST
LOW LEVEL FLOW STRENGTHENS THROUGH THE AFTERNOON AND EVENING. THIS
WILL BE SUFFICIENT FOR A SOLID LATE DAY DIURNAL RESPONSE...HIGHS
SETTLING INTO THE MIDDLE AND UPPER 80S. MUCH LIKE THIS PAST
EVENING...THIS PROCESS ALONE MAY PROVE ADEQUATE TOWARD GENERATING
WIDELY SCATTERED CONVECTION AS INSTABILITY BUILDS. A FIRM CAP WILL
REMAIN PROBLEMATIC...SO BETTER COVERAGE WOULD BE A STRUGGLE UNDER
THIS ENVIRONMENT. THERE IS SUPPORT FOR ANOTHER RIDGE CRESTING
SHORTWAVE TO ANCHOR ANOTHER ROUND OF CONVECTION ACROSS THE UPPER MS
VALLEY AT THE SAME TIME. SLIGHTLY BETTER DIURNAL DYNAMIC RESPONSE
ATTENDANT WITH THIS WAVE...WITH MAINTENANCE AND POSSIBLE UPSCALE
GROWTH EXPECTED ALONG THE MAIN INSTABILITY GRADIENT BACKED BY A
30-35 KNOT VEERING LOW LEVEL JET. 850-300 MB MEAN FLOW AND
PROJECTED CORFIDI VECTORS AGAIN PRESENT LOWER MICHIGAN IN A
FAVORABLE DOWNSTREAM POSITION...MOST FAVORED TIME TONIGHT WITHIN THE
00Z-07Z WINDOW. ORGANIZED CONVECTION BEHIND BULK SHEAR VALUES IN
EXCESS 30 KNOTS WILL BRING THE RISK OF STRONGER WIND GUSTS. A HIGH
PWAT AIRMASS WILL ALSO CONTRIBUTE TO POSSIBLE LOCALLY HEAVY
RAINFALL.
LONG TERM...WEDNESDAY THROUGH MONDAY
WEATHER OVER MICHIGAN WILL CONTINUE TO BE DOMINATED BY FLOW OVER THE
TOP OF THE LARGE UPPER RIDGE OVER THE CENTRAL PLAINS...BEFORE WE
START TO SEE SOME NORTHERN STREAM CONTRIBUTIONS OVER THE HOLIDAY
WEEKEND.
AREA OF LOW PRESSURE AND WEAK FRONT WILL CONTINUE TO DROP THROUGH
SOUTHERN LOWER MICHIGAN WEDNESDAY MORNING. GFS FORECAST SOUNDINGS
FOR DTW START TO SHOW SIGNIFICANT DRYING AND A CAP FORMING AS HIGH
PRESSURE BUILDS IN AFTER 18Z...AND WILL KEEP LOW CHANCES FOR
SHOWERS/TSTORMS ALONG/SOUTH OF M-59 ONLY THROUGH MID-DAY. MODELS
THEN REMAIN IN STRONG AGREEMENT WITH SURFACE HIGH PRESSURE BUILDING
INTO THE CENTRAL GREAT LAKES WEDNESDAY NIGHT THROUGH
THURSDAY...KEEPING THE WEATHER DRY. AIRMASS WILL REMAIN WARM EVEN
BEHIND THE FRONT WITH H850 TEMPERATURES ONLY COOLING TO 16-18 C FOR
WEDNESDAY AND THURSDAY. WITH GOOD INSOLATION THIS SHOULD KEEP
TEMPERATURES IN THE LOW AND MID 80S BOTH DAYS...SLIGHTLY COOLER
OVER THE THUMB WHERE FLOW WILL BE OFF LAKE HURON.
MODELS HAVE THEN KEYED IN ON A SHORTWAVE WITH ORIGINS OVER THE
DESERT SOUTHWEST THEN RIDING ATOP THE RIDGE AND ACROSS NORTHERN
MICHIGAN LATE THURSDAY NIGHT AND FRIDAY. THIS SETUP INITIALLY LOOKS
SLIGHTLY SIMILAR TO TODAY...A FRONT SETTLING IN OVER MICHIGAN AS
UPPER ENERGY OVER CANADA PUSHES SURFACE LOW PRESSURE TOWARDS THE
AREA. THERE ARE STILL QUITE A FEW DIFFERENCES BETWEEN THE MODELS
HOWEVER...BUT THE GENERAL IDEA IS FOR THIS INITIAL WAVE AND
POTENTIALLY A FEW OTHERS TO RIDE OVER THE FRONTAL BOUNDARY THAT WILL
BE DRAPED OVER THE REGION. THIS WILL PROVIDE A CHANCE FOR SHOWERS
AND THUNDERSTORMS FRIDAY AND SATURDAY. THE BIG DIFFERENCE BETWEEN
TODAY`S PATTERN AND THE SET-UP FOR LATER IN THE WEEK WILL BE A
FAIRLY STRONG UPPER TROUGH PUSHING THROUGH CENTRAL CANADA AND
ARRIVING INTO THE GREAT LAKES ON EITHER SATURDAY OR SUNDAY. WHILE
GFS AND EURO DIFFER WITH THE OVERALL SET-UP AND TIMING...THEY DO
AGREE WITH PUSHING A STRONG COLD FRONT DOWN ACROSS THE AREA ON
SUNDAY...PROVIDING A CONTINUATION OF CHANCES FOR SHOWERS/TSTORMS.
DRIER AIRMASS SHOULD WORK INTO THE AREA BEHIND THE FRONT...GFS
ACTUALLY HAS A SECONDARY FRONT DROPPING THROUGH ON MONDAY NOW AS
HIGH PRESSURE SETTLES DOWN INTO THE AREA. TEMPERATURES LOOK TO
REMAIN WARM WITH ABOVE NORMAL TEMPERATURES INTO THE
WEEKEND...ALTHOUGH CONVECTION COULD LIMIT HEATING AT TIMES.
TEMPERATURES SHOULD THEN COOL BEHIND THE FRONT FOR LABOR DAY...WITH
CURRENT FORECAST CARRYING MAX TEMPS ONLY IN THE 70S.
MARINE...
MOIST AND UNSTABLE ENVIRONMENT WILL SUPPORT THUNDERSTORM DEVELOPMENT
THROUGH TONIGHT. OUTSIDE OF THIS THUNDERSTORM RISK...MARINE
CONDITIONS WILL REMAIN QUITE FAVORABLE THROUGH WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SS
UPDATE.......SS
SHORT TERM...MR
LONG TERM....HLO
MARINE.......MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1245 PM CDT TUE AUG 27 2013
.AVIATION...18Z TAF ISSUANCE...
LOW CLOUDS CONTINUE TO ERODE ACROSS THE SRN TERMINALS...FROM BRD
TO HYR THIS MORNING...AND SHOULD BECOME VFR BY 19/20Z. WILL SEE
SCATTERED CONVECTIVE CU FIELD THIS AFTERNOON...EVENTUALLY
DISSIPATE BY THE EVENING AND FOG/LOW CLOUDS DEVELOP AROUND OR JUST
AFTER MIDNIGHT. WITH LIGHT WINDS AND MOSTLY CLEAR SKIES ALL
AROUND...FOG EXPECTED AT ALL FCST TERMINALS...WITH LIFR VSBYS AND
CIGS THROUGH 12/14Z.
&&
.PREV DISCUSSION... /ISSUED 1054 AM CDT TUE AUG 27 2013/
UPDATE...
AT 1045AM/1545Z...THERE WAS A FRONT STRETCHING FROM WEST TO EAST
JUST SOUTH OF THE FORECAST AREA. THE SOUTHERN FORECAST AREA HAD
CLOUDY SKIES...WHILE THE NORTHERN HALF WAS SUNNY. THERE WAS LITTLE
IF ANY WIND ACROSS THE NORTHLAND. TEMPERATURES WERE IN THE 70S.
I UPDATED THE FORECAST THROUGH THIS EVENING...FOCUSING ON CLOUD
COVER AND THE CHANCES OF SHOWERS AND STORMS. BASED ON THE LATEST
MODELS...ESPECIALLY THE HRRR AND RAP13 MODELS...I BELIEVE THERE
ARE EVEN LOWER CHANCES OF SHOWERS AND STORMS ACROSS THE SOUTHERN
AND SOUTHEASTERN FORECAST AREA THAN PREVIOUSLY FORECASTED. I
LOWERED THE CHANCES OF PCPN...AND MOSTLY CONFINED THE CHANCES
THROUGH THE AFTERNOON TO NW WISCONSIN. IF ANY STORMS DO
DEVELOP...THERE COULD BE A FEW STRONG STORMS WITH SMALL HAIL.
THE CLOUD COVER ACROSS THE SOUTHERN FORECAST AREA IS MOSTLY
REMNANTS FROM MORNING FOG. IT SHOULD CONTINUE TO LIFT AND BREAK
APART THROUGH EARLY THIS AFTERNOON. OTHERWISE...THE NORTHLAND CAN
EXPECT MOSTLY TO PARTLY SUNNY SKIES BY MID AFTERNOON.
TEMPERATURES SHOULD STILL BE QUITE HOT TODAY WITH HIGHS MOSTLY IN
THE UPPER 80S AND LOW 90S EXCEPT CLOSER TO LAKE SUPERIOR. HEAT
INDICES WILL BE AROUND 95 DEGREES ACROSS THE FAR SOUTHERN FORECAST
AREA FOR A BRIEF TIME DURING THE MID TO LATE AFTERNOON.
PREV DISCUSSION... /ISSUED 644 AM CDT TUE AUG 27 2013/
AVIATION...12Z TAF ISSUANCE...
WIDESPREAD LOW STRATUS WITH BR/FG THIS MORNING AS UNUSUALLY MOIST
AIR REACHES SATURATION AT SFC. EXPECT IMPROVEMENT AT MOST SITES BY
14Z TO 15Z AS SUNSHINE WORKS ON EVAPORATION OF LOW STRATUS LAYER.
OTHERWISE VFR THROUGH THE DAY ALTHOUGH SPOTTY CONVECTION MAY
REDEVELOP NEAR KDLH/KHYR/KBRD TERMINALS. EXPECT FOG/BR TO
REDEVELOP THIS EVENING AND MAY NEED TO LOWER VIS/CIGS IN NEXT TAF
FCST.
PREV DISCUSSION... /ISSUED 335 AM CDT TUE AUG 27 2013/
SHORT TERM...THROUGH EARLY WEDNESDAY AFTERNOON.
A FRONTAL BOUNDARY WAS DRAPED ACROSS THE REGION THIS
MORNING...FROM SOUTH DAKOTA ACROSS CENTRAL MINNESOTA INTO NORTHERN
WISCONSIN. THIS FEATURE HAS BEEN THE FOCUS FOR CONTINUED
THUNDERSTORMS OVERNIGHT...ALTHOUGH THERE FINALLY DOES SEEM TO BE A
BACK EDGE. LITTLE WAS OCCURRING ACROSS AITKIN/ITASCA
COUNTIES...WITH MOST OF THE STORMS OVER FAR NORTHERN WISCONSIN
BACK INTO THE TWIN PORTS/MOOSE LAKE AREAS. A LARGE AREA OF PWAT
VALUES AROUND 2 INCHES WAS OVER THE AREA WITH FGEN AIDING IN
FORCING. WE EXPECT ADDITIONAL SHOWERS AND STORMS TO FORM OVERNIGHT
INTO THIS MORNING. THE AREA OF STORMS WAS SINKING SOUTHWARD
SOME...SO WE WILL CONTINUE THE FLASH FLOOD WATCH FOR A COUPLE MORE
HOURS AT LEAST. AREAS OVER FAR NORTHERN WISCONSIN CONTINUE TO GET
RAIN...HEAVY IN SPOTS. THE HEAVIEST RAIN TONIGHT SO FAR APPEARS TO
BE OVER THE SANDIER SOILS OF BAYFIELD/DOUGLAS COUNTIES. WE`LL HAVE
TO MONITOR THOUGH...AND MAY NEED TO ISSUE A FLOOD ADVISORY. THERE
IS STILL A SMALL SEVERE THREAT THIS MORNING...MAINLY OVER
NORTHWEST WISCONSIN...WITH DAMAGING WINDS BEING THE MAIN THREAT. A
SMALL SEVERE THREAT WILL LINGER OVER OUR EASTERN WISCONSIN ZONES
INTO THE AFTERNOON AS WELL.
THIS AFTERNOON...THE LOW WILL MOVE EAST AND SOUTH OF THE CWA. IT
WILL REMAIN VERY WARM AND HUMID THOUGH WITH TEMPERATURES IN THE
UPPER EIGHTIES TO LOWER NINETIES. AN ONSHORE WIND OR RAIN WILL
KEEP AREAS AROUND LAKE SUPERIOR INCLUDING THE SOUTH SHORE COOLER.
WE DID NOT ISSUE ANY HEAT ADVISORIES TODAY...AS HEAT INDICES WILL
MAINLY BE IN THE LOWER TO MIDDLE NINETIES.
WE EXPECT IT TO BE DRY TONIGHT WITH SOME FOG POSSIBLE.
WE ALSO KEPT IT DRY ON WEDNESDAY WITH WEAK HIGH PRESSURE IN
CONTROL. IT WILL BE WARM...WITH HIGHS IN THE UPPER EIGHTIES TO
LOWER NINETIES. IT WILL AGAIN BE COOLER AROUND LAKE SUPERIOR.
EXTENDED FORECAST...WEDNESDAY NIGHT THROUGH TUESDAY...
CWA WILL REMAIN UNDERNEATH THE SRN EDGE OF THE WESTERLIES THROUGH
THE WEEK BEFORE CHANGES ARE ADVERTISED BY MED RANGE NWP. ECMWF WAS
OUTLIER YESTERDAY IN ITS AMPLIFICATION OF THE UPPER TROF OVER AND
EAST OF THE REGION THIS WEEKEND. THE GFS/GEM ARE NOW TRENDING IN
THAT DIRECTION AS WELL. CONFIDENCE IS INCREASING THAT AFTER THE
HEAT/HUMIDITY THIS WEEK A RETURN TO CLIMO AND PERHAPS BLO CLIMO
CONDITIONS WILL OCCUR LATE THIS WEEKEND AND EARLY NEXT WEEK.
UNTIL THEN ANOTHER ROUND OF CONVECTIVE ACTIVITY SHOULD OCCUR
THUR/FRIDAY AS A SHORTWAVE TROF TRAVERSES THE NRN FRINGE OF THE
UPPER RIDGE. AS USUAL THE TIMING OF THE SPECIFICS RELATED TO AN
MCC/MCS DEVELOPMENT ARE NOT A HIGH CONFIDENCE ENDEAVOR AT THIS
POINT. THE INITIAL ESTIMATE IS THAT A WARM ADVECTION REGIME WILL
INCREASE INSTABILITY THURSDAY. GEM/GFS/EC POSITION GREATEST PERIOD
OF 85H MSTR TRANSPORT OVER CWA BETWEEN 18Z THUR-06Z FRIDAY.
CONVECTION SHOULD MOVE EAST OF THE CWA FRIDAY WITH DECREASING POPS
WEST TO EAST. AT THIS POINT THE UPPER FLOW BEGINS TO SHIFT TO UPPER
RIDING OVER THE WRN CONUS AND TROUGHING OVER THE ERN GTLKS. TO
ASSIST THIS TRANSFORMATION...A MIGRATORY SHORTWAVE WILL DESCEND
ACROSS THE REGION AMIDST DEEPENING UPPER TROUGH AND SWING A FAIRLY
STRONG COLD FRONT ACROSS THE CWA SATURDAY NIGHT. FCST MAX TEMPS
SATURDAY MAY NEED SIGNIFICANT ADJUSTMENT DUE TO POTENTIAL OF
PREFRONTAL COMPRESSION AND ADVECTION OF SIGNIFICANT LOW LVL THERMAL
RIDGE AHEAD OF STRONG FRONT. EC FCST 85H TEMPS DROP FROM 18C TO 2C
OVER NRN MN ZONES FROM 0Z SUN TO 0Z MON. GEM/GFS ARE MUCH LESS
AGGRESSIVE IN MAGNITUDE BUT DO LOWER TEMPS SUBSTANTIALLY. SHOULD SEE
A POTENTIAL FOR CONVECTION AHEAD OF FRONT SATURDAY EVENING. MAY BE
BLUSTERY BEHIND FRONT SUNDAY BASED ON FCST KINEMATICS AND MECHANICAL
MIXING IN BDRY LYR SUNDAY AFTERNOON. PLEASANT WX APPEARS MORE
PROBABLE WE HEAD INTO THE NEW WEEK.
&&
.POINT TEMPS/POPS...
DLH 63 86 65 80 / 10 0 10 40
INL 58 87 64 79 / 0 0 20 50
BRD 65 91 68 86 / 0 0 30 50
HYR 62 90 65 82 / 10 0 10 30
ASX 62 83 62 79 / 10 0 10 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
215 PM EDT TUE AUG 27 2013
.SYNOPSIS...
WEAK SHORTWAVES CROSSES TODAY...UNDER NORTHWEST FLOW ALOFT. COLD
FRONT CROSSES WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE VISITS
BRIEFLY FRIDAY BEFORE PATTERN REPEATS.
&&
.NEAR TERM /THROUGH TONIGHT/...
1115 AM UPDATE. ADJUSTED LIKELY POPS TO POTENTIAL NEW MCS
DEVELOPMENT UPSTREAM FAIRLY EARLY THIS AFTERNOON...THEN DROPPING
SOUTH SOUTHEAST.
PREVIOUS DISCUSSION...
HIGH LEVEL CLOUDS ASSOCIATED WITH A DYING MCS ACROSS LAKE MICHIGAN
WILL COVER THE AREA THIS MORNING. NORTHWEST FLOW ALOFT...AND
EMBEDDED SHORTWAVES ARE EVIDENT IN VORT MAX FIELD ON H5 CHARTS.
ALTHOUGH IT LOOKS LIKE CONVECTIVE FEEDBACK...PIECES OF ENERGY
LOOKS REAL ACTING AS FORCING MECHANISMS.
THE HRRR MODEL BRINGS REMNANTS OF GREAT LAKES MCS OVER CKB...EKN
AND NORTHEAST MOUNTAINS THIS AFTERNOON. ANOTHER SHORTWAVE IS
EVIDENT IN H5 CHARTS APPROACHING THE AREA FROM THE NORTHWEST
WEDNESDAY.
NAM AND RUC MODELS SUGGEST AFTERNOON AND EVENING CONVECTION IN QPF
AND SFC CAPE FIELDS ALTHOUGH THE LATER LOOKS OVERDONE BY THE NAM
WITH DEWPOINTS IN THE LOW TO MID 70S. AN AREA OF DEEP LAYERED
SHEAR MOVES INTO SOUTHEAST OH AND PORTIONS OF WV THIS AFTERNOON.
EXPECT CONVECTIVE INITIATION WITH FEW STORMS BUT DO NOT EXPECT
THEM TO BECOME SEVERE.
CODED SKY AND POP GRIDS PER LATEST SATELLITE AND RADAR IMAGES. MID
LEVEL CLOUDS ADVECTING FROM THE NORTHWEST ACROSS SOUTHEAST OHIO
SITES SUCH AS PKB AND HTS EARLY THIS MORNING.
USED THE CONS MOS FOR TEMPERATURE THROUGH THE PERIOD.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ACTIVE WEATHER MAINLY THE FIRST HALF OF THE SHORT TERM PERIOD...WITH
PRECIP CHANCES AND POSSIBLE SUBSEQUENT HYDRO ISSUES PRIMARILY WED
AND WED NIGHT.
WEDNESDAY...AREA REMAINS UNDER NORTHWEST FLOW ALOFT WHILE AT THE SFC
SOUTHWEST WINDS IN PLACE. THOUGH DIFFS EXIST WITH STRENGTH AND
PLACEMENT...CONSENSUS OF NWP OUTPUT IS IN FAIRLY DECENT AGREEMENT
DRAGGING A COUPLE OF VORT MAXES ACROSS THE NORTHEASTERN ZONES FROM
NW TO SE ON WED. FIRST RIPPLE PUSHES INTO THE AREA RIGHT AROUND 12Z
WED AND OVER THE CENTRAL PART OF THE AREA BY 18Z WED. APPEARS THE
BEST OVERALL MOISTURE DEPTH NOT REALLY CO-LOCATED WITH BEST OVERALL
FORCING INITIALLY...WITH THE BEST MOISTURE OVER THE NE ZONES AND
BETTER DYNAMIC FORCING STILL TO THE WEST AND NORTHWEST AT 12Z WED.
HOWEVER OMEGA FIELDS INDICATE AMPLE LIFT THROUGH A DEEP LAYER ACROSS
THE NE ZONES AND WITH PLENTY OF MOISTURE IN PLACE WILL CONTINUE
CATEGORICAL POPS NE ZONES AT THE OUTSET. EXPECT SHOWERS AND
THUNDERSTORMS TO QUICKLY RAMP UP ACROSS THE NORTH AND NW ZONES AS
WELL DURING THE MORNING HOURS WITH THE APPROACH OF THE
AFOREMENTIONED VORT MAX AND ITS ASSOC LIFT...AS WELL AS LARGE SCALE
FORCING FOR ASCENT. BY THE AFTERNOON HOURS THE NEXT VORT MAX ON
NORTHWEST FLOW ALOFT PUSHES INTO THE NW ZONES BY 00Z THU. MODELS
STILL DIFFER ON THE PLACEMENT OF THE ASSOC SFC LOW...ALTHOUGH THEY
ARE TRYING TO COME CLOSER TOGETHER. STILL...LATEST NAM DEPICTS SFC
LOW STILL WELL WEST NEAR CINCINNATI AT 00Z THU WHILE OP GUIDANCE HAS
IT FURTHER EAST/NORTHEAST IN THE AREA OF OUR SE OHIO ZONES. GEFS
MEAN AND ITS MEMBERS SUPPORT THE FURTHER EAST SOLN AS DOES THE SREF
MEAN AND THUS WILL LEAN THE FORECAST IN THIS DIRECTION...WITH THE
LOW AND FRONT ENTERING INTO NW ZONES BY 00Z THU. ALL IN ALL WILL
CONTINUE TO TREND HIGHEST POPS FROM THE NE ZONES TOWARDS THE CENTRAL
AND SOUTHERN ZONES BY 00Z THU. EXPANDED THE COVERAGE OF CATEGORICAL
POPS TO INCLUDE GENERALLY LOCATIONS ALONG AND NORTHEAST OF A
BKW-CRW-PERRY COUNTY OH LINE AS IN THE END MOST IF NOT ALL OF THOSE
LOCATIONS SHOULD SEE SOME MEASURABLE RAINFALL BY DAY/S END ON
WEDNESDAY...THOUGH PINPOINTING THE TIMING ISN/T QUITE SO
STRAIGHTFORWARD. QPF AMOUNTS STILL RUNNING AROUND 0.75IN TO
1.00IN...AND WITH 3-HR FFG GUIDANCE AROUND 2 INCHES THERE IS CONCERN
FOR THE POSSIBILITY OF FLASH FLOODING. STILL NOT QUITE ENOUGH
CONFIDENCE TO ISSUE A WATCH AT THIS POINT AND WILL LET THE DAYSHIFT
TAKE ONE MORE LOOK AT IT. WILL CONTINUE HYDRO CONCERN MENTION
HOWEVER IN HWO AND DID GO AHEAD AND INCLUDE HEAVY RAIN WORDING IN
THE WX GRIDS WED.
PRECIP EXPECTED TO COME TO AN END FROM NW TO SE OVERNIGHT WED NIGHT
AS THE FRONT SWEEPS ACROSS THE AREA. MOST LOCATIONS WILL BE DRY ON
THURSDAY WITH THE FRONT WELL EAST OF THE AREA UNDER A PARTLY CLOUDY
SKY AND HIGHS GENERALLY IN THE MID 80S FOR LOWLAND LOCATIONS. WILL
KEEP INHERITED SLIGHT CHANCE AND LOW CHANCE POPS FOR THE
EAST/SOUTHEAST HIGH TERRAIN WITH A DECENT SLUG OF LLVL MOISTURE
REMAINING ALONG WITH SFC CONVERGENCE ON THE RIDGETOPS PROGGED.
THURSDAY NIGHT ALL LOCATIONS SHOULD DRY OUT WITH THE LOSS OF DAYTIME
HEATING. SFC HIGH PRESSURE CONTINUES TO MOVE EASTWARD AWAY FROM THE
AREA WITH RETURN SOUTHEAST FLOW SETTING UP. THIS...ALONG WITH
ANOTHER S/W TROUGH AND ASSOC VORT MAX MOVING INTO THE NORTHERN ZONES
BY AND AFTER 06Z FRI LENDS SOME POTENTIAL FOR LIGHT SHOWER
REDEVELOPMENT ON THE EAST SLOPES TOWARDS THE DAWN HOURS FRIDAY
MORNING. WILL LEAVE FORECAST DRY FOR NOW.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
GENERALLY FOLLOWED HPC IN EXTENDED WHICH WILL FEATURE QUIETER AND
DRIER WX DESPITE CONTINUING NW FLOW ALOFT. TEMPS RUNNING IN MID
80S AND LOWS GENERALLY IN 60S. GUIDANCE CONT TO RUN ON WARM
SIDE...AS HAS BEEN THE CASE MUCH OF THIS SUMMER. THINK WITH WET
GROUNDS THIS SEASON...FELT HEDGING A LITTLE BELOW GUIDANCE WAS
WARRANTED.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
18Z TUESDAY THRU 18Z WEDNESDAY...
GENERALLY VFR CEILINGS OUTSIDE OF ANTICIPATED MCS REDEVELOPMENT JUST
NORTH OF OUR AREA BY 19Z...DROPPING SOUTHEAST REMAINDER OF
AFTERNOON...REACHING EAST PORTIONS OF AREA BY 00Z. MAIN EFFECT OF
THE COMPLEX WILL BE IN THE PKB...CKB...EKN...TERMINALS. SO WILL
CARRY PREVAILING SHRA.TSRA THESE TERMINAL AND VCTS ELSEWHERE.
EXPECT RAPID WEAKENING SHORTLY AFTER 00Z...OF WHICH AN MVFR CEILING
MAY FORM BEHIND THE DYING COMPLEX.
DIFFICULT TO PROJECT THE NEXT IF ANY MCS LATER TONIGHT...BUT WILL
REDO THE SAME AREA AFTER 06Z FOR ORGANIZED CONVECTION. WILL KEEP
MOSTLY VFR OVERNIGHT THOSE AREAS THAT DO NOT RECEIVE RAIN...DUE TO
EXPECTED CLOUDS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY
THRU THE PERIOD...ALONG WITH DEVELOPMENT OF OVERNIGHT STRATUS/FOG.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H M M M M M H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H M M M M H H H H H H H
CKB CONSISTENCY H H H H H H H H H M H H
AFTER 18Z WEDNESDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS WEDNESDAY
AFTERNOON...MAINLY SOUTH.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KMC/JMV/30
NEAR TERM...ARJ/JMV
SHORT TERM...30
LONG TERM...30
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
141 PM EDT TUE AUG 27 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE OVER THE GULF STATES AND UPPER LEVEL HIGH
PRESSURE IN THE CENTRAL PLAINS WILL DOMINATE THE WEATHER MAP FOR
THE NEXT FEW DAYS. A COLD FRONT WILL TRACK FROM THE WESTERN GREAT
LAKES THROUGH THE OHIO VALLEY ON WEDNESDAY. BEHIND THIS...HIGH
PRESSURE AT THE SURFACE WILL SETTLE OVER NORTHERN OHIO FOR A DRIER
YET STILL WARM PERIOD AT THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID LEVEL RIDGE CENTERED OVER THE CENTRAL UNITED STATES WILL KEEP
OUR REGION IN NORTHWEST FLOW ALOFT. REMNANT MCS CURRENTLY DROPPING
DOWN ACROSS NORTHERN OHIO SHOULD CONTINUE TO WEAKEN THROUGH THE
REST OF THIS MORNING BUT SOME ISOLATED SHOWER/THUNDERSTORM
ACTIVITY WILL LIKELY AFFECT OUR FAR NORTHEAST. DEBRIS CLOUDS
ASSOCIATED WITH THIS WILL LINGER ACROSS AT LEAST THE NORTHEAST HALF
OF OUR FA INTO EARLY AFTERNOON. THIS WILL RESULT IN SOME
UNCERTAINTY AS TO HOW MUCH DESTABILIZATION WE WILL SEE LATER THIS
AFTERNOON. WOULD EXPECT CLOUDS TO THIN/DISSIPATE ENOUGH TO ALLOW
FOR SOME RECOVERY THOUGH...RANGING FROM THE UPPER 80S NORTHEAST TO
NEAR 90 POSSIBLY LOWER 90S ACROSS OUR FAR SOUTHWEST. THIS WILL
RESULT IN ML CAPES IN THE 1500 TO POSSIBLY AS HIGH 2500 J/KG
RANGE LATE THIS AFTERNOON...WITH A SOUTHWEST TO NORTHEAST GRADIENT
ACROSS OUR AREA. BIG QUESTION IS TRACK/TIMING/INTENSITY OF
SECONDARY REMNANT MCS NOW PUSHING DOWN INTO NORTHERN MI. LATEST
NAM/RAP SUGGESTING THE BEST ACTIVITY ASSOCIATED WITH THIS WILL
REMAIN MORE OFF TO OUR NORTHEAST WHILE THE LATEST HRRR IS
INDICATING IT MAY TRACK A LITTLE FARTHER WEST LATE THIS AFTERNOON.
THINK BEST GUESS WOULD BE THAT IT WILL TRACK DOWN ALONG THE
NORTHEAST EDGE OF THE BETTER INSTABILITY GRADIENT...WHICH WOULD
ALLOW FOR IT TO AFFECT AT LEAST OUR NORTHEASTERN AREAS. AS A
RESULT...WILL BUMP UP POPS ACROSS ABOUT THE NORTHEAST THIRD OF
OUR FA...BUT STILL KEEP THEM IN THE HIGH CHANCE CATEGORY DUE TO
THE UNCERTAINTY. BEST DEEP AND MID LAYER SHEAR WILL ALSO REMAIN
ALONG AND NORTHEAST OF OUR FA LATER TODAY SO EXPECT BEST CHANCE
FOR ANY SEVERE STORMS THROUGH THIS AFTERNOON TO BE ACROSS OUR
NORTHEASTERN. THE PRIMARY SEVERE THREAT WOULD BE DAMAGING WINDS
AND POSSIBLY LARGE HAIL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
IF IT WAS NOT STATED IN THE NEAR TERM...MODELS ARE NOT HANDLING
THE ONGOING WEATHER WELL AND DIFFER VASTLY IN THEIR INTERPRETATION
OF THE STATE OF THE WEATHER IN THE SHORT TERM. THE HIGH
TEMPERATURES REACHING INTO THE 90S AND INCREASED MOISTURE THROUGH
THE PERIOD WILL LEAD TO INCREASED THREAT FOR STORMS...ESPECIALLY
ON WEDNESDAY AS A FAIRLY PREDICTABLE COLD FRONT WORKS THROUGH THE
OHIO VALLEY AND SPARKS CONVECTIVE ACTIVITY.
THE LIKELY CHANCES OF STORMS IN THE LATE AFTERNOON AND EVENING
WERE NOT AS CUT AND DRY AS I WOULD PREFER TO CARRY SO POPS WERE
LOWERED FOR THIS TIME TO JUST CHANCE. THE BETTER CHANCE FOR
SHOWERS ON WEDNESDAY WILL OCCUR IN THE NORTHEAST BUT COULD BE
COMPROMISED BY CLOUD COVER LIMITING THE SURFACE BASED INSTABILITY
THAT WILL BE NECESSARY FOR STORMS TO PROGRESS. THIS CLOUD COVER
WILL ALSO PUT THE DAYS HIGH TEMPERATURES IN QUESTION WHERE THE
FORECAST UPPER 80S COULD BE 5 DEGREES TOO HIGH OR SO.
DRIER AIR IN THE WAKE OF THE COLD FRONT WILL BE THE DIFFERENCE IN
THE AIRMASS...NOT NECESSARILY COLDER TEMPERATURES.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
NUMERICAL MODEL SOLNS SHOWING WEAK PERTURBATIONS DROPPING SE
AROUND THE PERIPHERY OF THE MID LEVEL RIDGE. THEREFORE...CAN NOT
RULE OUT VERY LOW POP/ISOLD SHOWERS/THUNDERSTORMS TOWARD THE END
OF THE WEEK INTO NEXT WEEKEND. THESE FEATURES ARE WEAK AND
DIFFICULT TO TIME...AND WITH PROB BEING SO LOW WILL MAINTAIN DRY
FCST THRU FRIDAY NIGHT AND THEN ONLY ALLOW A SLIGHT CHANCE MAINLY
ACROSS THE WEST SATURDAY AFTN. ON SUNDAY A LITTLE MORE SIGNIFICANT
S/W MAY LEAD TO PRECIPITATION. WILL CONTINUE TO LIMIT POPS TO
CHANCE CATEGORY WITH THIS FEATURE. TEMPERATURES REMAIN CLOSE TO 10
DEGREES ABOVE NORMAL WITH HIGHS SAT/SUN UPPER 80S NE TO LOWER 90S
SW.
DETERMINISTIC NUMERICAL MODEL SOLNS HAVE BEEN DIFFERING ON HOW MUCH
THE MID/UPR LEVEL RIDGE PUSHES BACK EAST INTO THE OHIO VALLEY. 00Z
GFS BEING MORE AGGRESSIVE WITH THE RIDGE THAN THE ECMWF AND WAS
HOLDING THE SFC FRONT TO OUR NORTH...WHILE ECMWF WAS PUSHING THE
FRONT THRU ON MONDAY. 12Z DETERMINISTIC GFS RUN HAS TRENDED MORE
TOWARD THE ECMWF...SO WILL ALLOW FOR AN INCREASE IN POPS DURG THE
DAY MONDAY TO ACCOUNT FOR THIS FRONT. TEMPERATURES SLIGHTLY COOLER
MONDAY WITH HIGHS RANGING FROM MID 80S NORTH TO UPPER 80S SOUTH.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
REMNANTS OF EARLIER MCS OVER NORTHEAST OHIO HAVE PRETTY MUCH
DISSIPATED BUT A FAIR AMOUNT OF DEBRIS CLOUDINESS IS LINGERING
ACROSS OUR AREA THIS AFTERNOON. AS A RESULT...TEMPERATURES AND
INSTABILITY ARE STRUGGLING SOMEWHAT TO RECOVER. MODELS ARE HAVING A
DIFFICULT TIME RESOLVING HOW TO HANDLE POSSIBLE REDEVELOPMENT
LATER TODAY INTO TONIGHT WITH THE REMNANTS OF THE SECONDARY MCS PUSHING
DOWN ACROSS LOWER MICHIGAN. THE 12Z GFS/NAM/CMC ARE GENERALLY
KEEPING THE BEST ACTIVITY WITH THIS OFF TO OUR NORTHEAST..BUT
SOME OF THE HIGHER RES MODELS ARE SUGGESTING SOME DEVELOPMENT
FARTHER WEST INTO THE BETTER INSTABILITY. WILL GO AHEAD AND ALLOW
FOR A VCTS FOR KCMH/KLCK HEADING INTO THIS EVENING TO COVER THE
THREAT. TOUGH TO RULE OUT AN ISOLATED CHANCE AT THE OTHER TAF
SITES BUT WILL LEAVE THEM DRY DUE TO THE LOW PROBABILITY/UNCERTAINTY.
A COLD FRONT WILL SAG SOUTHEAST TOWARD THE AREA LATER TONIGHT INTO
WEDNESDAY MORNING. AHEAD OF THIS A DEVELOPING WESTERLY LOW JET
WILL NOSE INTO NORTHERN OHIO LATE TONIGHT. THIS COULD LEAD TO SOME
ADDITIONAL REDEVELOPMENT ACROSS OUR NORTH BUT THE BETTER FORCING
APPEARS TO REMAIN TO OUR NORTHEAST. WILL THEREFORE TREND TOWARD A
DRIER SOLUTION AND JUST ALLOW FOR A VCSH AT KCMH/KLCK LATE IN THE
TAF PERIOD.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...JGL
SHORT TERM...FRANKS
LONG TERM...AR
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
340 PM CDT TUE AUG 27 2013
.SHORT TERM...(Tonight and Wednesday)
Isolated shower activity will be ending this evening, as an easterly
wave moves northwest. HRRR model seems to have been the better
model, indicating rapid weakening showers this afternoon. The NAM
and GFS models had more extensive coverage this afternoon over the
Big Country and Concho Valley. In any case...all models show
precipitation ending by early evening with loss of the suns heating.
Some patchy stratus possible late tonight and early Wednesday
morning...due to moist vegetation and light winds. Temperatures
rebound into the lower and mid 90s Wednesday with dry conditions and
and mostly sunny skies.
.LONG TERM...(Thursday through Tuesday)
Dry and hot weather to prevail through the weekend.
The ECMWF and the GFS are still in good agreement, indicating that
once the wave moves out of the area tomorrow, the upper level high
pressure will settle back into the area. With the high dominating
the weather across the southern plains, looks like dry conditions
will prevail. The center of the high pressure will shift from the
mid Mississippi Valley on Wednesday, to Texas on Thursday, and into
the southern Rockies for the weekend. Since we dont see the center
of the high sit directly over West Central Texas, temperatures are
more likely to be in the mid and upper 90s to near 100 rather than
something much warmer. But in any case, dry and warmer than normal
conditions will be the rule.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 71 95 71 97 72 / 10 5 5 5 5
San Angelo 70 93 70 96 71 / 10 5 5 5 5
Junction 70 93 70 95 70 / 10 5 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/07
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
326 PM CDT TUE AUG 27 2013
.SHORT TERM...
TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.
HEAT ADVISORY REMAINS IN EFFECT UNTIL 01Z WEDNESDAY. SEVERAL
AUTOMATED SITES HAVE ALREADY REACHED THE 100 DEGREE HEAT INDEX
VALUE...AND MORE SHOULD REACH OVER THE NEXT FEW HOURS. GOOD MIXING
WITH SOUTHWEST WINDS HAVE HELPED TEMPERATURES RISE INTO THE LOWER TO
MID 90S. MADISON MAY GET CLOSE TO RECORD HIGH OF 95.
COLD FRONT IS EXPECTED TO SHIFT SOUTHWARD THROUGH THE AREA MAINLY
THIS EVENING. HRRR AND WRF 4KM MODELS NOW BRING THE FRONT THROUGH
THE AREA BETWEEN 00Z AND 06Z WEDNESDAY. THE HRRR IS SHOWING LITTLE
IN THE WAY OF ANY SHOWER/STORM ACTIVITY...WITH THE WRF 4KM MODEL
SHOWING A BROKEN LINE OF WEAK TO MODERATE SHOWERS/A FEW STORMS WITH
THE FRONT. UPWARD VERTICAL MOTION WITH THE FRONT IS EXPECTED TO BE
SOMEWHAT WEAK...WITH THE NAM TOO AGGRESSIVE WITH LOW LEVEL
FRONTOGENESIS RESPONSE.
500MB VORTICITY MAXIMUM OVER NORTHERN WISCONSIN IS EXPECTED TO SLIDE
SOUTHEAST AND CLIP THE NORTHEAST PORTIONS OF THE FORECAST AREA LATE
THIS AFTERNOON AND EARLY THIS EVENING. ADJUSTED AREA FORECAST
SOUNDINGS SHOWING CAP NEARLY MIXING OUT BY 22Z TUESDAY...WITH AT
LEAST 2000 J/KG MEAN LAYER CAPE AND DEEP LAYER SHEAR OF 30 TO 40
PLUS KNOTS...BEST SHEAR TOWARD SHEBOYGAN. SOME INDICATION FOR
ROTATING STORMS PER SPC SSEO PAGE AS WELL. IF CONVECTION DOES
DEVELOP...SEVERE STORMS ARE POSSIBLE GIVEN THESE PARAMETERS...WITH
STRONG WINDS AND LARGE HAIL THE MAIN HAZARDS. SEE LATEST SPC DAY 1
OUTLOOK AND RECENT MESOSCALE DISCUSSION FOR MORE INFORMATION.
GIVEN SOME UNCERTAINTY WITH HOW MUCH CONVECTION WILL
FORM...CONTINUED CHANCE POPS IN THE NORTHERN AND EASTERN PORTIONS OF
THE AREA...CLOSEST TO THE PASSING 500MB VORTICITY MAXIMUM AND BETTER
SHEAR.
WARM TEMPERATURES REMAIN ACROSS THE AREA AFTER FRONTAL PASSAGE LATER
TONIGHT INTO WEDNESDAY...AS WELL AS DEW POINTS IN THE UPPER 60S TO
LOWER 70S. SOME CONCERN WITH CLOUDS OVER NORTHERN WISCONSIN WILL
PUSH SOUTHWARD LATER TONIGHT AND LINGER INTO WEDNESDAY. BROUGHT IN
THESE CLOUDS LATER TONIGHT...BUT MIXED THEM OUT WEDNESDAY. WINDS
WILL SHIFT TO THE NORTH NORTHEAST DURING LATER TONIGHT INTO
WEDNESDAY. ANY FOG THAT DEVELOPS SHOULD REMAIN PATCHY...THOUGH GIVEN
HIGH DEW POINTS MAY BECOME MORE WIDESPREAD. LATER SHIFTS WILL HAVE
TO MONITOR.
QUIET WEATHER IS EXPECTED WEDNESDAY...WITH SOME DIURNAL CUMULUS
POSSIBLE IN THE AFTERNOON. HIGHS WILL STILL REACH WELL INTO THE 80S
AWAY FROM THE LAKE...WITH AROUND 80 NEAR IT.
WEDNESDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM
THE BROAD UPPER RIDGE WILL BE CENTERED OVER THE SOUTH CENTRAL USA THROUGH
THE PERIOD WITH NW FLOW ALOFT OVER WI. AT THE SFC...HIGH PRESSURE
WILL PREVAIL OVER SRN WI WED NT AND THU...BUT HIGH CLOUDS WILL
INCREASE ON THU AS A SLOW MOVING WAVE OF LOW PRESSURE APPROACHES
FROM THE NW. THE HIGH CLOUDS MAY KEEP TEMPS DOWN JUST A LITTLE FOR
THU...BUT STILL A WARM AND HUMID DAY.
A SLOW MOVING WAVE OF LOW PRESSURE WILL THEN TRACK ACROSS THE
REGION FROM THU NT INTO FRI...BUT ON SOME MODELS COULD LINGER INTO
SAT. A COUPLE WEAK VORTICITY MAXIMUMS WILL HELP GUIDE THE LOW SEWD
DURING THIS PERIOD. BEST TIME PERIOD FOR PCPN CHANCES IS THU NT
AND FRI WHEN LOW TO MID LEVEL WARM ADVECTION AND FRONTOGENESIS
AFFECTS THE REGION. SHOWALTER INDICES INCREASE TO -4C FOR LATE THU
NT WHILE LIS FOR FRI COULD REACH -8C. EXPECT THIS LIFT AND
INSTABILITY TO OVERCOME WEAK CAPPING SO POPS MAX OUT AROUND 50-60
PERCENT EITHER THU NT OR FRI. LOW POPS THEN LINGER INTO SATURDAY
SINCE LOW COLD BE SLOW TO DEPART. MAX HEAT INDICES DURING THIS
TIME WILL RANGE FROM THE MID 80S TO MID 90S WITH GREATEST HEAT
OVER SOUTH CENTRAL WI. SOME COOLING IS EXPECTED EACH DAY IN FAR
ERN WI VIA THE LAKE MI LAKE BREEZE.
.LONG TERM...
SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM
EXTENDED MODELS CONTINUE TO PRODUCE STRONG CYCLOGENESIS OVER SRN
CANADA FOR THE WEEKEND. THE LOW WILL MOVE EAST ACROSS SRN CANADA
WITH THE TRAILING COLD FRONT EXPECTED TO ARRIVE OVER SRN WI EITHER
SUN OR SUN NT. MODELS ARE STILL HAVING A DIFFICULT TIME ON THE
STRENGTH OF COOLING WITH THE FROPA BUT OVERALL MUCH COOLER TEMPS
ARE EXPECTED FOR EARLY NEXT WEEK COMPARED TO A COUPLE DAYS AGO.
HIGH TEMPS IN THE 70S ARE FORECAST FOR LABOR DAY AND TUE. POPS
CHANCES REMAIN LOW WITH THE MOSTLY DRY FROPA AND THEN DRY AFTER
FROPA.
&&
.AVIATION/00Z TAFS/...
PREVAILING VFR CONDITIONS EXPECTED THROUGH
THIS EVENING...WITH MVFR/IFR VISIBILITIES POSSIBLE IN ANY STORMS
WITH PASSING COLD FRONT. FOG WITH MVFR/IFR VISIBILITIES POSSIBLE
BETWEEN 06Z AND 14Z WEDNESDAY. VFR CONDITIONS RETURN FOR THE REST OF
WEDNESDAY...AS HIGH PRESSURE MOVES INTO THE REGION.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE BETWEEN 00Z AND 06Z
WEDNESDAY AT TAF SITES...BEST CHANCES AT THE EASTERN SITES. SOME
UNCERTAINTY IF STORMS WILL FORM AND HOW WIDESPREAD THEY WILL BE...SO
WILL LEAVE VICINITY WORDING IN TAFS FOR NOW. MVFR/IFR VISIBILITIES
POSSIBLE WITH ANY STORMS...ALONG WITH GUSTY WINDS AND HAIL.
GUSTY SOUTHWEST WINDS ARE EXPECTED INTO EARLY THIS EVENING...BEFORE
COLD FRONT PUSHES SOUTH THROUGH THE AREA BETWEEN 00Z AND 06Z
WEDNESDAY. LIGHT WINDS SHIFT TO THE NORTH NORTHEAST BEHIND THE
FRONT...THEN REMAIN NORTH NORTHEAST THROUGH WEDNESDAY. MODERATE
NORTH NORTHEAST WINDS ARE EXPECTED AT THE EASTERN TAF SITES BY
WEDNESDAY AFTERNOON.
&&
.MARINE...PATCHY FOG SEEMS TO HAVE MIXED OUT ON WEB CAMERAS AT
SHEBOYGAN AND PORT WASHINGTON...WITH MODERATE SOUTH WINDS MIXING
THIS FOG OUT. GUSTY WINDS AT MARINE OBSERVATION SITES ARE AT SMALL
CRAFT CRITERIA...BUT THESE SHOULD BEGIN TO WEAKEN SHORTLY...SO WILL
NOT ISSUE AN ADVISORY.
SHOULD SEE AT LEAST PATCHY FOG DEVELOP LATER TONIGHT INTO EARLY
WEDNESDAY WITH MOIST AIRMASS OVER THE COOL LAKE WATERS. SOME
POTENTIAL FOR MORE WIDESPREAD FOG DURING THIS TIME.
KEPT CHANCE WORDING FOR SHOWERS AND THUNDERSTORMS THROUGH THIS
EVENING. SOME UNCERTAINTY WITH IF AND HOW WIDESPREAD STORMS WILL
BE...GIVEN WEAK COLD FRONT MOVING THROUGH. SEVERE STORMS WITH STRONG
WINDS AND LARGE HAIL ARE POSSIBLE IF ANY STORMS DO DEVELOP. QUICK
WIND SHIFT TO THE NORTH NORTHEAST IS EXPECTED WITH THE FRONTAL
PASSAGE LATER THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR WIZ046-047-051-052-
056>060-062>072.
LM...NONE.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...WOOD
WEDNESDAY NIGHT THROUGH TUESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1239 PM CDT TUE AUG 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT TUE AUG 27 2013
..CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER
TROUGH JUST OFF THE PACIFIC NORTHWEST COAST AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUE TO ROTATE AROUND THE RIDGE...TRACKING FROM ARIZONA INTO THE
DAKOTAS AND THE FORECAST AREA. PRECIPITABLE WATER VALUES MAX OUT IN
THE 2-2.25 INCH RANGE FROM CENTRAL MN INTO NORTHERN WI PER RAP
ANALYSIS. CLUSTERS OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
MONSOONAL SHORTWAVES AS WELL AS 850MB-700MB MOISTURE TRANSPORT HAVE
BEEN TRACKING THROUGH THIS PRECIPITABLE WATER MAX. BLOWOFF FROM THIS
CONVECTION ENCOMPASSES MUCH OF THE FORECAST AREA. AIRMASS IS VERY
WARM ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THE 00Z MPX RAOB
REPORTED A 25C 850MB TEMP AND 27C 925MB TEMP...WHICH TRANSLATED TO A
HIGH YESTERDAY OF 97F AT MSP. BETWEEN THE HOT TEMPERATURES
YESTERDAY...THE BLOWOFF...A LIGHT SOUTHERLY BREEZE AND DEWPOINTS
HOLDING IN THE LOW 70S...TEMPERATURES HAVE STRUGGLED TO DROP THIS
MORNING. READINGS ARE STILL MAINLY BETWEEN 75 AND 80. SURFACE
PRESSURE ANALYSIS SHOWED LOW PRESSURE NEAR MONTEVIDEO MN...WITH A
WARM FRONT STRETCHING INTO TAYLOR COUNTY AND A COLD FRONT BACK INTO
CHAMBERLAIN SOUTH DAKOTA.
..HAZARDS..
1. HEAT. HAVE KEPT ALL GOING HAZARDS INTACT. CONSIDERED UPGRADING
FLOYD...CHICKASAW AND FAYETTE COUNTIES TO EXCESSIVE HEAT
WARNING...BUT HEAT INDICES APPEAR MARGINAL TO DO SO.
2. STORMS. SEVERE POTENTIAL...PARTICULARLY THIS AFTERNOON NORTH AND
EAST OF I-94.
3. FOG LATE TONIGHT...WHICH COULD END UP BEING DENSE...ESPECIALLY
WHERE IT RAINS.
..SYNOPTIC OVERVIEW..
THE SUBTROPICAL RIDGE OVER KANSAS AND MISSOURI IS PROGGED TO STAY
PUT THROUGH TONIGHT. HOWEVER...A CHANGE IN THE UPPER AIR PATTERN IS
TO HAVE SOME RIDGE BUILD NORTH TONIGHT INTO THE DAKOTAS. THIS...IN
TURN...HELPS TO TURN THE FLOW MORE NORTHWESTERLY OVER THE FORECAST
AREA. A SERIES OF MONSOONAL SHORTWAVES ROTATING AROUND THE RIDGE ARE
FORECAST TO COME THROUGH NORTHEASTERN PORTIONS OF THE FORECAST AREA
THROUGH TONIGHT...HELPING TO PUSH THE SURFACE LOW AND COLD FRONT
SOUTHEAST THROUGH THE ENTIRE AREA BY 12Z WEDNESDAY.
..DETAILS..
PRECIPITATION...WITH 850MB AND 700MB MOISTURE TRANSPORT FOCUSED INTO
THE AREA NORTHEAST OF I-94 THIS MORNING...THERE REMAINS POTENTIAL
FOR CONVECTION JUST FROM THIS THERMODYNAMIC FORCING. HOWEVER...THINK
THE GREATER POTENTIAL FOR CONVECTION WILL COME THIS AFTERNOON AS A
SHORTWAVE PRESENTLY WEST OF FARGO COMES THROUGH CENTRAL WISCONSIN AT
PEAK HEATING. VERY GOOD MODEL CONSENSUS FOR CONVECTION TO OCCUR
NORTHEAST OF I-94 IN THE AFTERNOON...WITH EVEN A POSSIBILITY OF IT
EXTENDING BACK TOWARDS LA CROSSE. THIS CONVECTION WILL SLIDE
SOUTHEAST OF THE AREA DURING THE EVENING...WITH ALL OF IT LIKELY OUT
BY 03Z. DRY CONDITIONS ARE EXPECTED ELSEWHERE DUE TO CAPPING AND
LIMITED CONVERGENCE ON THE COLD FRONT...AND DRY CONDITIONS ARE
ANTICIPATED ONCE THE FRONT PASSES AS SUBSIDENCE AND DRYING WORK IN.
SEVERE POTENTIAL...0-6KM SHEAR IS DECENT IN THE MORNING...35-45 KT
NORTHEAST OF I-94. HOWEVER...NOT ANTICIPATING MUCH OF THE MORNING
CONVECTION TO BE ABLE TO UTILIZE THIS SHEAR. DURING THE AFTERNOON
WHEN CAPE IS AT ITS HIGHEST...THE 0-6KM SHEAR IS WEAKENING TO 30-35
KT. NONETHELESS...WITH MLCAPES OF 2000-2500 FT COMBINING WITH THIS
SHEAR SHOULD ALLOW FOR SOME STORM ORGANIZATION...LIKELY IN THE FORM
OF MULTICELLS WITH A SUPERCELL POSSIBLE. FREEZING LEVELS UP NEAR
16000 FT SHOULD LIMIT HAIL...BUT CERTAINLY DAMAGING WINDS AND VERY
HEAVY RAIN ARE POSSIBLE GIVEN THE UNSEASONABLY WARM...MOIST
ENVIRONMENT.
HEAT...925MB TEMPERATURES TODAY ARE PROGGED VERY SIMILAR TO
YESTERDAY AHEAD OF THE COLD FRONTAL PASSAGE...RUNNING BETWEEN
27-29C. SO WE SHOULD SEE READINGS THAT ARE SIMILAR AS WELL. AROUND
CHARLES CITY THE READINGS APPROACH 30C...SO IT IS POSSIBLE THEY WILL
END UP A LITTLE WARMER.
LASTLY...A POTENTIAL ISSUE TO DEAL WITH LATE IN THE NIGHT IS FOG.
THE FRONT THAT COMES THROUGH TONIGHT IS QUITE SHALLOW AND STRUGGLES
TO GET THESE HIGHER DEWPOINTS OUT OF HERE. WITH COOLER AIR COMING IN
BEHIND THE FRONT AND LIGHT SURFACE WINDS...WE MAY END UP WITH SOME
SHALLOW FOG...PARTICULARLY SOUTHWEST OF I-94. SREF VISIBILITY PROGS
SHOW THIS NICELY. HAVE RAISED THE FOG COVERAGE AND WILL HAVE TO
WATCH FOR POSSIBLE DENSE FOG.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 316 AM CDT TUE AUG 27 2013
..HAZARDS..
1. HEAT. DEWPOINTS LOOK A LITTLE BIT HIGHER FOR WEDNESDAY...THOUGH
TEMPERATURES WILL NOT BE NEARLY AS WARM THE PAST FEW DAYS.
THEREFORE...HEAT INDICES ONLY TOP OUT IN THE 90S...JUST BELOW
ADVISORY CRITERIA. FARTHER AHEAD...AN ADVISORY IS LOOKING MORE
LIKELY FOR FRIDAY...PARTICULARLY NORTHEAST IOWA AND FAR SOUTHWEST
WI. NO ADVISORIES NEEDED NOW FOR THE WEEKEND.
..SYNOPTIC OVERVIEW..
27.00Z MODEL GUIDANCE IN GOOD AGREEMENT SHOWING THAT THE SUBTROPICAL
RIDGE OVER KANSAS AND MISSOURI WILL RETROGRADE WESTWARD INTO THE
FOUR CORNERS REGION BY SATURDAY. THE LAST COUPLE OF DAYS MODELS HAD
SUGGESTED THAT THE RIDGE WOULD HEAD BACK EAST. HOWEVER...THIS IS NOW
DELAYED BECAUSE OF A SHORTWAVE TROUGH COMING OUT OF SOUTHWEST CANADA
ON FRIDAY THAT ENDS UP DIGGING INTO THE GREAT LAKES REGION ON
SUNDAY. THE 26.00Z ECMWF WAS FIRST TO SHOW THIS AND NOW ALL MODELS
HAVE CAPTURED ONTO THE IDEA. THE ONLY QUESTION NOW IS TIMING AND
AMPLIFICATION OF THIS TROUGH...WHICH THERE IS A DECENT SPREAD ON
COME SUNDAY.
..DETAILS..
WITH THE FRONTAL BOUNDARY SOUTH OF THE AREA ON WEDNESDAY AND HIGH
PRESSURE IN PLACE...HAVE CONTINUED THE DRY FORECAST. AS MENTIONED IN
THE HAZARDS SECTION...HIGHER DEWPOINTS DOES RAISE CONCERN FOR
EXTENSION IN THE HEAT ADVISORY. HOWEVER...925MB TEMPS OF 25-27C WILL
RESULT IN COOLER HIGHS...KEEPING HEAT INDICES BELOW ADVISORY LEVEL.
A SERIES OF SHORTWAVES ARE PROGGED TO COME ACROSS THE NORTHERN
PLAINS AND INTO THE NORTHERN GREAT LAKES REGION WEDNESDAY NIGHT
THROUGH FRIDAY. THE SHORTWAVES WEDNESDAY NIGHT AND THURSDAY ARE
PROGGED TO HELP BRING THE COLD FRONT BACK TOWARDS US...AND
ISENTROPIC LIFT/MOISTURE TRANSPORT OVER THE FRONT RESULTS IN CONCERN
FOR CONVECTION. THE GREATEST CHANCES FOR CONVECTION WEDNESDAY NIGHT
AND THURSDAY WILL TRACK JUST NORTH OF THE AREA...CLOSER TO THE
SHORTWAVES...BUT THE ISENTROPIC LIFT COULD SPREAD SOME SHOWERS AND
THUNDERSTORMS DOWN INTO THE FORECAST AREA...ESPECIALLY WEST OF THE
MS RIVER AND OVER NORTH CENTRAL WISCONSIN. HAVE CONTINUED 20-30
PERCENT CHANCES. THESE CHANCES GRADUALLY ENCOMPASS MORE OF THE AREA
HEADING INTO THURSDAY NIGHT AND ESPECIALLY FRIDAY. ON FRIDAY...
MODELS ARE IN GOOD AGREEMENT SHOWING A SHORTWAVE COMING THROUGH
CENTRAL MN AND SOUTHEAST INTO THE FORECAST AREA AT THE TIME OF PEAK
HEATING. 0-6KM SHEAR ONLY PROGGED 20-25 KT...SO NOT THINKING SEVERE
AT THIS TIME. TEMPERATURES WILL COOL DOWN BRIEFLY ON THURSDAY
BETWEEN CLOUDS/POTENTIAL CONVECTION AND 925MB TEMPS OF 22-26C.
HOWEVER...TEMPERATURES LOOK TO SHOOT BACK UP ON FRIDAY AHEAD OF THAT
SHORTWAVE COMING THROUGH. COOLING WILL OCCUR FRIDAY NIGHT WITH
PASSAGE OF THE SHORTWAVE TROUGH.
HEADING INTO LABOR DAY WEEKEND...WARM AIR COULD TRY TO SURGE BACK
INTO THE AREA ON SATURDAY...AHEAD OF THE MORE POTENT SHORTWAVE
TROUGH CROSSING SOUTH CENTRAL CANADA. ONLY HAVE SOME VERY LOW
CHANCES OF PRECIPITATION IN...MAINLY TOWARDS CENTRAL WISCONSIN WHERE
ISENTROPIC LIFT LOOKS GREATEST. BIGGEST CONCERN COMES SUNDAY AND
MONDAY WITH HOW MUCH COLD AIR COMES IN BEHIND THE COLD FRONT
ASSOCIATED WITH THE SHORTWAVE TROUGH...ALONG WITH TIMING TOO. 27.00Z
ECMWF IS VERY AGGRESSIVE DIVING 925MB TEMPS DOWN TO 6C BY 12Z
MONDAY. COMPARE THIS TO THE 27.00Z GFS WHICH ARE 16-20C...DRAMATIC
DIFFERENCE. THUS...TEMPERATURE FORECASTS ARE LOW CONFIDENCE. GIVEN
THE COOLER SIGNAL IN THE ECMWF...FELT IT WAS APPROPRIATE TO LOWER
HIGHS...LOWS AND DEWPOINTS FOR SUNDAY THROUGH MONDAY NIGHT ABOUT 5
OR SO DEGREES FROM THE PREVIOUS FORECAST. RAIN CHANCES LOOK MINIMAL
FOR SUNDAY THROUGH MONDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1239 PM CDT TUE AUG 27 2013
THE MAIN FOCUS AT THE TAF SITES IS WITH WHETHER ANY STORMS WILL
DEVELOP THIS AFTERNOON AHEAD OF A COLD FRONT...FOLLOWED BY THE
POTENTIAL FOR FOG TONIGHT. AN UNSTABLE ATMOSPHERE HAS DEVELOPED
AHEAD OF A COLD FRONT RUNNING EAST TO WEST FROM NORTHEAST
WISCONSIN TO CENTRAL MINNESOTA. THERE IS A CHANCE FOR CONVECTION
TO DEVELOP ALONG THE FRONT THIS AFTERNOON...MAINLY IN CENTRAL TO
EASTERN WISCONSIN AND AWAY FROM THE TAF SITES. HIGHER CONFIDENCE
EXISTS IN THE DEVELOPMENT OF FOG TONIGHT BEHIND THE COLD FRONT.
HUMIDITY LOOKS LIKE IT STAYS UP EVEN BEHIND THE FRONT WHILE
TEMPERATURES ARE DROPPING. WITH CLEAR SKIES AND LIGHT
WINDS...EXPECT THAT THIS COMBINATION WILL LEAD TO SOME FOG
DEVELOPMENT OVERNIGHT WITH CONDITIONS DROPPING TO IFR OR LOWER
BETWEEN 8-14Z.
&&
.CLIMATE...
ISSUED AT 334 PM CDT MON AUG 26 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR WIZ017-029-034-
042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR WIZ032-033-
041.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR MNZ086-087-094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR MNZ079-088-
096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1222 PM CDT TUE AUG 27 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 336 AM CDT TUE AUG 27 2013
AREA RADARS CONTINUE TO SHOW STORMS FORM OVER MN AND MOVE INTO/
THROUGH NORTHERN WI. SO FAR STORMS HAVE NOT TRAINED OVER SAME
LOCATION WITH HEAVY RAIN FALLING IN NARROW BANDS. STORMS NOW OVER
NW WI...TO MOVE INTO CWA AFT 10Z. WILL NEED TO BE WATCHED AS SHEAR
INCREASING OVER NORTHERN WI ATTM. STORMS NOT EXPECTED INTO FFA AREA
UNTIL 12Z OR AFTER...SO HAVE DECIDED TO DROP HEADLINE. MAIN ISSUE
OF THIS FORECAST IS PCPN TRENDS.
FORCING FOR STORMS OVERNIGHT FGEN/WAA SHIFTING EAST WITH 850 WINDS
BECOMING WESTERLY BY MORNING. TODAYS FORCING TO BE MORE TIED INTO
RIDGE RIDING DISTURBANCES AND LOCATION OF BOUNDARY. MODELS SUGGEST
BOUNDARY TO SHIFT SLOWLY SOUTH THROUGH CWA TODAY. HRRR NOT DOING
TO BAD ATTM...WITH CURRENT PCPN NORTH. HRRR TRENDS TO DIMINISH
PCPN DURING MORNING HOURS...THEN REDEVELOP OVER REGION FROM
MARINETTE TO TOMAHAWK BY MID AFTERNOON. AGAIN AREA IN SLIGHT RISK
FOR SEVERE WITH SIG INSTABILITY.
HIGH PRESSURE TO BUILD INTO STATE LATER TONIGHT AND WED...BRINGING A
BRIEF DRYING TREND.
TEMPS TODAY AGAIN HIGHLY DEPENDENT ON CLOUDS. WINDS BECOME A BIT
MORE ONSHORE TOO AS BOUNDARY SHIFTS SOUTH. HAVE TRENDED A BIT
COOLER NORTH AND FAR EAST...STAYING CLOSE TO YESTERDAYS READINGS.
AGAIN HEAT INDEX READINGS HIT 100 FOR COUPLE HOURS FAR SOUTHWEST
CWA. WILL STAY WITH SPS TO HIGHLIGHT AND NOT ISSUE ANY HEADLINE.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 336 AM CDT TUE AUG 27 2013
MDLS ARE IN GENERAL AGREEMENT ON THE LONG-RANGE MEAN FLOW ACROSS
THE CONUS WITH UPR TROFS JUST OFF THE WEST COAST AND WRN ATLANTIC
WITH AN UPR RDG SITUATED OVER THE CNTRL/SRN PLAINS. QUESTIONS
ARISE BY LATE IN THE WEEKEND WHETHER THE UPR RDG WL REMAIN
SOMEWHAT FLAT OR BUILD NWD THRU THE ROCKIES AS AN UPR TROF DIGS
TOWARD THE NE CONUS. AFTER A BRIEF RESPITE FROM THE HEAT/HUMIDITY
WED NGT/THU...RETURN FLOW MAKES A COMEBACK BRINGING PCPN CHCS BACK
TO THE REGION THU NGT/FRI WITH SEVERAL OTHER CHCS FOR PCPN THRU
THE UPCOMING WEEKEND.
NE WI TO REMAIN ON THE WRN FRINGE OF THE SFC HI THRU WED NGT...
THEREBY KEEPING WINDS LIGHT AND LEADING TO THE POTENTIAL OF MORE
FOG. THE EXACT EXTENT OF THE FOG IS A BIT UNCERTAIN AS MID AND UPR
LEVEL CLOUDS COULD BE MOVING INTO CNTRL WI AFTER MIDNGT AS WAA
BEGINS TO SPREAD NE FROM THE MIDWEST. HAVE KEPT FOG PATCHY FOR NOW
WITH MIN TEMPS RANGING FROM THE UPR 50S TO LWR 60S NORTH...60 TO
65 DEGS ELSEWHERE.
AS THE SFC HI DRIFTS TOWARD THE ERN GREAT LAKES ON THU...RETURN
FLOW SETS UP ACROSS WI WITH DEW POINTS STARTING TO CREEP UP ONCE
AGAIN. IN ADDITION...MDLS ARE SHOWING A SHORTWAVE TROF TOPPING THE
UPR RDG AND SLIDING E-SE TOWARD THE WRN GREAT LAKES BY LATE IN THE
DAY. BETWEEN THE LIFT FROM THE WAA AND THE START OF MID-LEVEL
FORCING FROM THE SHORTWAVE TROF...CANNOT RULE OUT A FEW SHWRS OR
TSTMS OVER CNTRL WI DURING THE AFTERNOON. AWAY FROM THE IMMEDIATE
LAKESHORE...EXPECT MAX TEMPS TO GENERALLY REACH THE LWR TO MID 80S.
THE SHORTWAVE TROF IS FCST TO MOVE SE INTO THE GREAT LAKES REGION
THU NGT AND HELP TO DRAG A WEAK FRONTAL BOUNDARY INTO NRN WI DURING
THE OVRNGT HOURS. WHILE INSTABILITY IS MARGINAL...SHEAR IS FAIRLY
STRONG TO SUSTAIN UPDRAFTS AND THERE IS A DIFFLUENT FLOW ALOFT
ADDING TO THE LIFT. PREFER TO GO WITH A MORE UNIFORM HI CHC POP
FOR NE WI...BUT BELIEVE THAT NRN PARTS OF THE STATE WOULD SEE
HIGHER QPF AMOUNTS AS FORCING A BIT STRONGER DUE TO THE PROXIMITY
OF THE SHORTWAVE TROF. THIS FRONTAL BOUNDARY WL SLOWLY SAG THRU WI
ON FRI...BUT BEGIN TO SLOW DOWN AS IT ENCOUNTERS THE EDGE OF THE
BROAD CNTRL/SRN PLAINS UPR RDG. A CONTINUED CHC OF SHWRS/TSTMS
ACROSS THE FCST AREA IS NECESSARY...ALTHO THE NORTH MAY SEE THE
PCPN COME TO AN END DURING THE AFTERNOON IF THE BOUNDARY CAN SLIP
FAR ENUF TO THE SOUTH. ANTICIPATED CLOUDS SHOULD HELP TO HOLD
TEMPS IN CHECK...BUT WITH 8H TEMPS STILL NEAR +20C...ANOTHER DAY
IN THE LWR TO MID 80S CAN BE EXPECTED.
THE MAIN QUESTION FOR THE FRI NGT/SAT TIME FRAME IS WHETHER THIS
BOUNDARY WL PUSH FAR ENUF SOUTH BEFORE STALLING TO AVOID THE
MENTIONING OF MORE PCPN. MDLS HAVE VARIOUS SOLUTIONS HERE...BUT
THE LATEST TRENDS DO SHOW THIS BOUNDARY SAGGING FAR ENUF TO AT
LEAST MINIMIZE THE PCPN CHCS OVER THE NORTH. NOT ENUF CONFIDENCE
TO COMPLETELY PULL THE POPS...BUT AT LEAST WL ATTEMPT TO TIER POPS
MORE FROM SOUTH TO NORTH.
A LOT OF UNCERTAINTY REMAINS FOR THE SUNDAY PERIOD AS THE ECMWF
BUILDS THE UPR RDG NWD THRU THE ROCKIES FASTER THAN THE OTHER
MDLS. THE ECMWF`S SOLUTION WOULD SEND A CDFNT THRU WI ABOUT 12
HOURS FASTER...THUS CLEARING THINGS OUT FOR SUNDAY AS OPPOSED TO A
SUNDAY FROPA ADVERTISED BY THE GFS/GEM. SINCE THIS IS MAJOR
PATTERN CHANGE...FULLY EXPECT THE MDLS TO WAFFLE ON TIMING OF THIS
FROPA...THUS HAVE FOLLOWED THE CONSENSUS MDL SOLUTION WHICH KEEPS
A LOW POP IN THE FCST THRU SUNDAY. A LARGE AREA OF HI PRES IS THEN
FCST TO BUILD INTO THE REGION FOR MON AND BRING COOLER/MUCH DRIER
AIR TO NE WI.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1213 PM CDT TUE AUG 27 2013
COLD FRONT ACROSS NORTHERN WISCONSIN WILL SAG SOUTHWARD ACROSS THE
AREA THIS AFTERNOON INTO EARLY THIS EVENING. CONVECTION ALREADY HAS
BROKEN OUT ACROSS FAR NORTHEAST WISCONSIN...THE CENTRAL AND NORTHERN
BAY OF GREEN BAY AND UPPER MICHIGAN. STORMS WILL CONTINUE TO FIRE
ALONG COLD FRONT AS IT DROPS SOUTHWARD THIS AFTERNOON AND EVENING.
SOME OF THE STORMS COULD CONTAIN LARGE AND WIND GUSTS OVER 50 KNOTS.
FOR THE 18Z TAFS...TRIED TO TIME THE BEST CHANCES FOR STORMS FROM
18Z-22Z AT KRHI TO 23Z-02Z AT KATW AS THE CLUSTER OF STORMS IS EXPECTED
TO DROP SOUTHWARD. OVERNIGHT...LOOK FOR AT LEAST IFR CONDITIONS ACROSS
MUCH OF THE AREA. CONDITIONS COULD REACH AIRPORT MINIMUMS DUE TO LOW
CLOUDS AND FOG. ANY LOW CLOUDS AND FOG SHOULD GRADUALLY IMPROVE
WEDNESDAY MORNING AS HIGH PRESSURE BUILDS INTO THE STATE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......KALLAS
AVIATION.......ECKBERG
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1209 PM CDT TUE AUG 27 2013
.UPDATE...ADDED THE REST OF THE FORECAST AREA TO THE HEAT
ADVISORY...IN EFFECT FROM NOON UNTIL 8 PM THIS EVENING. HRRR AND
WRF 4KM MODELS SHOWING SOUTHWEST WINDS PICKING UP DURING THE
AFTERNOON...WITH AN INCREASING PRESSURE GRADIENT. SOME GUSTS UP
TO 20 KNOTS OR SO ARE EXPECTED. THIS SHOULD HELP TEMPERATURES RISE
QUICKLY INTO THE LOWER TO MID 90S IN MOST OF THE AREA THIS
AFTERNOON. DEW POINTS POOLING IN THE LOWER 70S NEAR THE ADVANCING
COLD FRONT LATER THIS AFTERNOON SHOULD PREVENT MIX OUT OF THE DEW
POINTS.
THUS...HEAT INDEX VALUES OF AROUND 100 TO 105 ARE EXPECTED. SOME
AREAS RIGHT ALONG THE LAKESHORE MAY EXPERIENCE COOLER TEMPERATURES
WITH SOUTH SOUTHEAST WINDS AT TIMES...BUT SOUTHWEST WINDS AND THE
HOT HUMID CONDITIONS SHOULD LINGER ACROSS MOST OF THE AREA.
REMOVED THUNDER CHANCES FROM FORECAST IN THE FAR NORTH AND
NORTHEAST UNTIL LATER THIS AFTERNOON...AS THE COLD FRONT SHIFTS
SOUTHWARD TOWARD THE AREA. HRRR AND WRF 4KM MODELS BRING THE FRONT
THROUGH THE AREA BETWEEN 22Z TUESDAY AND 03Z WEDNESDAY. THESE
MODELS ARE SHOWING A MAINLY DRY FRONTAL PASSAGE. UPWARD VERTICAL
MOTION WITH THE FRONT IS SOMEWHAT WEAK...WITH THE NAM TOO
AGGRESSIVE WITH LOW LEVEL FRONTOGENESIS RESPONSE.
500MB VORTICITY MAXIMUM OVER EAST CENTRAL MINNESOTA IS EXPECTED TO
SLIDE SOUTHEAST THROUGH CENTRAL TO SOUTHEAST WISCONSIN DURING THE
AFTERNOON AND EARLY EVENING. ADJUSTED AREA FORECAST SOUNDINGS
SHOWING CAP MIXING OUT BY 21Z TO 22Z TUESDAY...WITH 1000 TO 1500
J/KG MEAN LAYER CAPE AND DEEP LAYER SHEAR OF 30 TO 35 KNOTS. SOME
INDICATION FOR ROTATING STORMS PER SPC SSEO PAGE AS WELL. IF
CONVECTION DOES DEVELOP...SEVERE STORMS ARE POSSIBLE GIVEN THESE
PARAMETERS...WITH STRONG WINDS AND LARGE HAIL THE MAIN HAZARDS.
FOR NOW...GIVEN SOME UNCERTAINTY WITH HOW MUCH CONVECTION WILL
FORM...CONTINUED CHANCE POPS IN THE NORTH AND EAST...CLOSEST TO
THE PASSING 500MB VORTICITY MAXIMUM.
&&
.AVIATION/18Z TAFS/...PREVAILING VFR CONDITIONS EXPECTED THIS
AFTERNOON AND THIS EVENING...WITH MVFR/IFR VISIBILITIES POSSIBLE
IN ANY STORMS WITH PASSING COLD FRONT. FOG WITH MVFR/IFR
VISIBILITIES POSSIBLE BETWEEN 06Z AND 14Z WEDNESDAY. VFR
CONDITIONS RETURN FOR THE REST OF WEDNESDAY...AS HIGH PRESSURE
MOVES INTO THE REGION.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE BETWEEN 22Z
TUESDAY AND 03Z WEDNESDAY AT TAF SITES...BEST CHANCES AT THE
EASTERN SITES. SOME UNCERTAINTY IF STORMS WILL FORM AND HOW
WIDESPREAD THEY WILL BE...SO WILL LEAVE VICINITY WORDING IN
EASTERN SITES FOR NOW. MVFR/IFR VISIBILITIES POSSIBLE WITH ANY
STORMS...ALONG WITH GUSTY WINDS AND HAIL.
GUSTY SOUTHWEST WINDS ARE EXPECTED THIS AFTERNOON INTO EARLY THIS
EVENING...BEFORE COLD FRONT PUSHES SOUTH THROUGH THE AREA BETWEEN
00Z AND 03Z WEDNESDAY. MODERATE WINDS SHIFT TO THE NORTH
NORTHEAST BEHIND THE FRONT...THEN BECOME LIGHT AND REMAIN NORTH
NORTHEAST THROUGH WEDNESDAY.
&&
.MARINE...PATCHY FOG SEEN ON WEB CAMERAS AT SHEBOYGAN AND MAINLY
AT PORT WASHINGTON...WITH MOIST AIRMASS OVER COOL SHORELINE
WATERS. INCREASING SOUTH WINDS SHOULD HELP MIX OUT THIS FOG BY
EARLY THIS AFTERNOON.
KEPT CHANCE WORDING FOR SHOWERS AND THUNDERSTORMS LATE THIS
AFTERNOON AND EARLY THIS EVENING. SOME UNCERTAINTY WITH IF AND HOW
WIDESPREAD STORMS WILL BE...GIVEN WEAK COLD FRONT MOVING THROUGH.
SEVERE STORMS WITH STRONG WINDS AND LARGE HAIL ARE POSSIBLE IF
ANY STORMS DO DEVELOP.
&&
.PREV DISCUSSION... /ISSUED 310 AM CDT TUE AUG 27 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM.
THE TWO MAIN ISSUES FOR TODAY INTO TONIGHT WILL BE THE HEAT AND THE
POTENTIAL FOR THUNDERSTORMS...WITH SOME POSSIBLY SEVERE.
CONVECTION TO OUR NORTH/NORTHEAST EARLY THIS MORNING WILL TRACK OFF
TO THE SOUTHEAST BY SUNRISE WITH THINGS LOOKING DRY INTO THE EARLY
AFTERNOON. THIS SHOULD GIVE THE CONVECTIVE DEBRIS PLENTY OF TIME TO
CLEAR OUT AND TEMPS TO RECOVER. AN IMPRESSIVE 925MB THERMAL RIDGE
IS PROGD TO PEAK OUT AROUND 28-29C ACROSS THE SOUTH BY LATE
AFTERNOON. THIS IS A FEW DEGREES HIGHER THAN YESTERDAY. DEW POINTS
SHOULD BE IN THE LOWER 70S AND THE COMBO STILL GIVES US HEAT INDICES
OF AROUND 100 ACROSS THE CURRENT HEAT ADVISORY AREA. THE NORTHEAST
FORECAST AREA SHOULD BE A FEW DEGREES COOLER DUE TO THE PROXIMITY TO
THE EARLY CONVECTION AND THE SUPPRESSED BAROCLINIC ZONE IN THAT AREA.
A COLD FRONT CURRENTLY STRETCHING FROM CENTRAL MN INTO NORTHERN
WISCONSIN WILL SAG TO ABOUT A TWIN CITIES TO GRB LINE BY 18Z...THEN
REACHING OUR NORTHERN CWA BY 00Z...AND SOUTH OF THE AREA BY AROUND
06Z. A MID LEVEL SHORT WAVE WILL BE ROUNDING THE TOP OF THE
RIDGE...MOVING THROUGH THE AREA DURING THE LATE AFTERNOON AND
EVENING. CAPES ARE EXPECTED TO CLIMB TO ABOUT 2500J/KG THIS
AFTERNOON WITH DEEP LAYER 0-6KM SHEAR ON THE ORDER OF 40KTS. THINGS
SHOULD BE CAPPED OFF ACROSS THE SOUTHWEST CWA...BUT THE NORTHEAST
HALF...NOT SO MUCH. SOME OF THE HI RES MODELS SHOW POTENTIAL FOR
STRONG STORM DEVELOPMENT FROM ABOUT MID AFTERNOON INTO THE EVENING
AND SPC HAS OUTLOOKED THE NE HALF IN A SLIGHT RISK. WILL KEEP THE
CHCY POPS FOR NOW AS THERE IS PLENTY OF UNCERTAINTY. IN FACT...THE
GFS KEEPS MOST ACTIVITY NORTH AND EAST OF THE FORECAST AREA.
WILL DRY IT OUT AFTER 06Z TONIGHT WITH COOLER TEMPS COMING IN BEHIND
THE DEPARTING FRONT FOR WEDNESDAY.
WEDNESDAY - CONFIDENCE...MEDIUM
SURFACE/850 RIDGING TAKES HOLD AS FRONTAL BOUNDARY SAGS SOUTH. NNE
FLOW BRINGS ONLY SUBTLE RELIEF FROM THE HEAT AND HUMIDITY. 925 TEMPS
STILL PROGGD INTO THE LOW-MID 20S CELSIUS AND DEW POINTS PROGGED
INTO THE UPPER 60S TO LOW 70S. APPEARS THE MORE DRAMATIC RELIEF WILL
BE NEAR LAKE MICHIGAN WITH THE COOLER TEMPS MORE LIKELY THERE GIVEN
THE WIND TRAJECTORY OFF THE LAKE.
THURSDAY - CONFIDENCE...MEDIUM
LINGERING HIGH PRESSURE IN CONTROL WITH BETTER RETURN FLOW AND
RENEWED BAROCLINICITY ACROSS ERN IA/ERN MN AND PORTIONS OF WRN AND
NRN WI. HOTTEST AIRMASS ACROSS IA/MN.
THURSDAY NIGHT AND FRIDAY - CONFIDENCE...MEDIUM
BROADLY ANTICYCLONIC 500 MILLIBAR FLOW TRANSITIONS TO MORE OF AN
ACTIVE NW FLOW REGIME WITH SHORTWAVE ENERGY KNOCKING DOWN THE RIDGE.
IN ADDITION...WARM AIR ADVECTION KICKS IN. 850/925 THERMAL GRADIENT
TIGHT IN THE MORNING THEN THERMAL RIDGE BECOMES PREDOMINANT IN THE
AFTERNOON. TOASTY READINGS ONCE AGAIN WITH 925 TEMPS INTO THE 26-29C
RANGE DURING PEAK HEATING ONCE REMNANT CLOUD DEBRIS ERODES.
CONSENSUS AMONGST OFFICES WAS TO BOOST HIGHS. WILL MAINTAIN SOME
POPS INTO THE AFTERNOON WITH WEAK SHORTWAVE ACTIVITY IN THE FLOW AND
UNSTABLE AIRMASS WITH CAPES OVER 1K J/KG. SOME CONCERN THAT CAP IN
THE SW MAY HAVE A SAY WITH 700 TEMPS PUSHING 12C. GFS PRECIP FIELDS
MAY BE OVERDONE HOWEVER EVEN THE ECMWF IS HINTING AT AFTERNOON
DEVELOPMENT. CAP PRETTY WEAK ON BUFKIT SOUNDINGS. WITH SURFACE/850
FRONT PUSHING IN FROM THE NORTH LATER IN THE DAY AND INTO THE
EVENING HOURS ANY CAP WILL LIKELY ERODE WITH ENOUGH LOW LEVEL
FORCING COMING INTO PLAY.
SATURDAY - CONFIDENCE...MEDIUM
LINGERING BAROCLINICITY NECESSITATES A CONTINUATION OF POPS. STILL A
SWIFT UPPER FLOW WITH POTENTIAL FOR A SHORTWAVE TO AID IN VERTICAL
MOTION AS WELL.
SUNDAY AND LABOR DAY - CONFIDENCE...MEDIUM
MAIN FOCUS IS ON ARRIVAL OF COOLER AIRMASS. MAY NEED TO EXTEND
SMALL POPS INTO SUNDAY MORNING WITH FRONTAL TIMING UNCERTAIN BUT
FOR NOW WILL GO WITH DRY FORECAST BUT PREFERRED ECMWF KEEPS MAIN
FOCUS TO OUR SOUTH AND EAST AS THE MORNING WEARS ON. 00Z ECMWF
HAS MAINTAINED THE 12Z SOLUTION OF SHOWING A MORE AMPLIFIED UPPER
AIR PATTERN WITH COOL SURGE ARRIVING SUNDAY NIGHT. LABOR DAY HAS
THE POTENTIAL TO BE QUITE COOL ESPECIALLY LAKESIDE. AFTERNOON 925
TEMPS ARE RUNNING 11C IN THE EAST TO 15C IN THE WEST WITH A NORTH
OR NORTHEAST WIND. CONSENSUS WITH SURROUNDING OFFICES WAS TO GO
WITH THE COOLER HPC TEMPS VERSUS THE WARMER ALLBLEND SOLUTION.
AVIATION/12Z TAFS/...GENERALLY LOOKING AT VFR CONDITIONS THROUGH THIS
EVENING. A COLD FRONT WILL BE APPROACHING FROM THE NORTH LATER
THIS AFTERNOON AND EVENING. THIS FRONT COULD BE THE FOCUS FOR
STRONG TO SEVERE STORMS...MAINLY FOR THE KMKE/KENW/KUES TAF SITES.
OUT TOWARD KMSN...THINGS MAY BE CAPPED OFF WITH LITTLE RISK OF
THUNDERSTORMS WITH THE FRONTAL PASSAGE. CONSISTENT WITH
THUNDERSTORMS...WE COULD SEE A BRIEF PERIOD OF MVFR CONDITIONS AS
STORMS MOVE THROUGH. FROPA AT MADISON IS EXPECTED AROUND 05Z AND
MILWAUKEE ABOUT 07Z.
IT APPEARS WE COULD SEE SOME MVFR CIGS/VSBYS ARRIVE BEHIND THE FRONT
LATE TONIGHT DUE TO WEAK COLD ADVECTION AND THE POSSIBILITY OF WINDS
TURNING ONSHORE ALONG LAKE MICHIGAN.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR WIZ046-047-051-052-
056>060-062>072.
LM...NONE.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...DAVIS
WEDNESDAY THROUGH MONDAY...COLLAR
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
334 PM MDT TUE AUG 27 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM MDT TUE AUG 27 2013
CURRENT KCYS RADAR LOOP SHOWS SOME SHALLOW CONVECTION DEVELOPING
OVER THE LARAMIE RANGE AND MOVING NORTHEAST INTO THE HIGH PLAINS
OF WYOMING THIS AFTERNOON. BELIEVE CONVECTION WILL BE MAINLY RAIN
SHOWERS WITH A FEW ISOLATED STRIKES OF LIGHTNING. THIS IS DUE TO
DRY AIR ALOFT MOVING THROUGH MOST OF THE FORECAST AREA
TODAY...WHICH IS DEPICTED WELL ON THE WATERVAPOR LOOP THIS
AFTERNOON. THIS DRY AIR ON THE WESTERN SIDE OF THE MAIN UPPER
LEVEL HIGH OVER KANSAS/MISSOURI WILL REMAIN OVER THE FORECAST AREA
THROUGH THURSDAY.
THE RIDGE AXIS EXTENDING NORTHEASTWARD FROM THE MAIN UPPER LEVEL
HIGH WILL PUSH ACROSS THE AREA ON WEDNESDAY. ALTHOUGH THE GFS IS
STILL MORE AGGRESSIVE WITH DEVELOPING AFTERNOON TSTORMS NEAR AND WEST
OF THE LARAMIE...BELIEVE THE DRY AIR AND SUBSIDENCE ALOFT WILL
GREATLY SUPPRESS COVERAGE OF THESE TSTORMS. KEPT POP BETWEEN 15 TO 25
PERCENT FOR THE LOWER ELEVATIONS AND UP TO 40 PERCENT FOR THE
MOUNTAINS. LOWERED POP BELOW 10 PERCENT EAST OF A LINE FROM
CHEYENNE TO ALLIANCE. HOT TEMPERATURES WILL CONTINUE AND SPREAD
WESTWARD INTO SOUTHEAST WYOMING ON WEDNESDAY WITH HIGHS IN THE LOW
TO MID 90S POSSIBLE. NEAR RECORD HIGHS AROUND 100 ARE EXPECTED
ACROSS WESTERN NEBRASKA...ALTHOUGH THE CURRENT RECORDS ARE ON THE
HIGH SIDE AT SIDNEY AND CHADRON...SO DO NOT EXPECT ANY RECORD
HIGHS WEDNESDAY. THURSDAY WILL LIKELY BE THE HOTTEST DAY OF THE
WEEK AS THE UPPER LEVEL HIGH SHIFTS WESTWARD INTO THE CENTRAL
ROCKIES. DUE TO EVEN MORE MIDLEVEL SUBSIDENCE...ANY SHOWERS AND
TSTORMS WILL BE BRIEF AND CONFINED TO THE MOUNTAINS. MODELS SHOW
LI/S ABOVE ZERO ACROSS MOST OF THE AREA...SO EXPECT MAINLY DRY
CONDITIONS ACROSS THE HIGH PLAINS WITH HIGHS BETWEEN 90 TO 100.
KEPT POP BELOW 10 PERCENT OUTSIDE OF THE MOUNTAINS AND HIGHEST
VALLEYS WEST OF THE LARAMIE RANGE.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 PM MDT TUE AUG 27 2013
LONG TERM LOOKS UNSEASONABLY WARM AS BOTH THE GFS AND ECMWF SHOW
THE MID-CONUS RIDGE MOVING WEST INTO COLORADO AND STICKING AROUND
FOR THE NEXT WEEK OR SO.
700MB TEMPERATURES REMAIN AT +16 TO +18C THROUGH SUNDAY MORNING.
LOOKING AT UPPER 90S AND NEAR 100 HIGHS FOR THE PANHANDLE AND
AREAS IN SOUTHEAST WYOMING EAST OF THE LARAMIE RANGE/MID TO UPPER
80S WEST. MAINLY DRY ACROSS THE CWFA...BUT CAN NOT RULE OUT
AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS FORMING OVER
THE MOUNTAINS AND THEN MOVING OFF ONTO THE PLAINS. DID
HOWEVER...REDUCE POPS FROM PREVIOUS FORECASTS.
LOOKS LIKE MONSOONAL MOISTURE RETURNS TUESDAY AS A PACIFIC STORM
SYSTEM MOVES INTO WASHINGTON STATE. THE LOW THEN MOVES NORTHEAST
INTO ALBERTA...BUT IT DOES HELP THE UPPER RIDGE AXIS TO MOVE OFF
TO THE EAST INTO THE WESTERN DAKOTAS. WE SHOULD SEE A SLIGHT COOL
DOWN IN TEMPERATURES AS THIS OCCURS WITH INCREASED CLOUD
COVER...POP CHANCES AND COOLING 700MB TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1051 AM MDT TUE AUG 27 2013
VFR CONDITIONS FOR OUR NEBRASKA PANHANDLE AIRPORTS AND RAWLINS
THROUGH THE NEXT 24 HOURS. LATEST HRRR FORECAST...WHICH HANDLED
CONVECTION YESTERDAY PRETTY WELL...HAS GREATEST CONCENTRATION OF
SHOWERS AND THUNDERSTORMS OVER ALBANY COUNTY AND KLAR. DOES BRING
SHOWERS AND THUNDERSTORMS INTO THE CHEYENNE AREA LATER THIS
AFTERNOON...AFTER ABOUT 23Z OR SO. SO TIMED CONVECTION BASED ON
THIS GUIDANCE. CONVECTION SHOULD COME TO AN END QUICKLY AFTER
SUNSET.
&&
.FIRE WEATHER...
ISSUED AT 147 PM MDT TUE AUG 27 2013
FIRE WEATHER CONCERNS WILL BE MINIMAL THROUGH THE WEEK WITH
DAYTIME HUMIDITIES GENERALLY REMAINING ABOVE 20 PERCENT...WITH
GREAT OVERNIGHT RECOVERIES. THE ONLY CONCERN WILL BE OVER THE NEXT
FEW DAYS WITH NEAR RECORD HIGH TEMPERATURES EXPECTED OVER THE HIGH
PLAINS. IF THE BOUNDARY LAYER MIXES A BIT HIGHER THAN MODEL
SOUNDINGS SUGGEST...LOCALLY LOWER HUMIDITIES AROUND 15 PERCENT ARE
POSSIBLE WITH HOT TEMPERATURES DUE TO THE DRIER AIR ALOFT. WINDS
WILL BE OCCASIONALLY GUSTY WEDNESDAY AFTERNOON...BUT DO NOT EXPECT
GUSTS TO APPROACH 30 MPH. NOT MUCH OF A PATTERN CHANGE
ANTICIPATED OVER THE NEXT 7 DAYS AS A STUBBORN UPPER LEVEL HIGH
WILL REMAIN NEARLY STATIONARY BETWEEN THE CENTRAL ROCKIES AND
CENTRAL GREAT PLAINS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...TJT